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Howard: And now the Kung Pao Chicken. 这是宫保鸡丁。
-Leonard: Ah, yeah. Wow. 啊，好，哇。
-Raj: Smooth. 厉害。
-Howard: And finally, my Moo Shu Pork. 最后，是我的木须肉。
-Raj: Whoo-hoo! 哇塞!-Howard: Oh, there you have it, gentlemen. Our entire dinner unpacked by robot.好了,先生们,你们都看到了机器人已经把所有饭菜取出来了。
-Raj: And it only took 28 minutes. 仅仅花了28分钟时间。
-Sheldon: Impressive, but we must be cautious.真不错啊，不过我们得小心点。
-Howard: Why? 为什么?-Sheldon: Today, it's a Chinese food retrieval robot. Tomorrow, it travels back in time and tries to kill Sarah Connor.今天，这是个中餐传递机器人，明天，它会及时地穿越时空，回去谋杀Sarah Connor(终结者外传女主人公)。
-Leonard: I don't think that's going to happen, Sheldon.Sheldon 我可不相信会发生这样的事情。
-Sheldon: No one ever does. That's why it happens.。
没人相信所以才会发生啊。
-Penny: Hey. Is the food here? Ooh. What's that?嘿，外卖都到了? 哇，那是什么?-Howard: That, dear lady, is the Wolowitz Programmable Hand, designedfor extravehicular repairs on the International Space Station.专门为国际空间站的舱外维修而设计的。
我们应该谈谈宇宙英文作文英文：The universe is a fascinating topic that has intrigued humans for centuries. From the stars in the sky to the planets in our solar system, there is so much to explore and discover. As for me, I have always been interested in astronomy and the mysteries of the universe.One of the most interesting things about the universe is its sheer size. It's difficult to even comprehend just how vast it is. For example, our own Milky Way galaxy is estimated to contain between 100 and 400 billion stars. And that's just one galaxy out of countless others in the universe.Another fascinating aspect of the universe is the concept of black holes. These are areas in space where the gravitational pull is so strong that nothing, not even light, can escape. It's a mind-boggling concept, but it'salso something that scientists are still trying to understand.Of course, there are also many practical applicationsof studying the universe. For example, understanding the movements of celestial bodies can help us predict thingslike eclipses and meteor showers. And the study of space travel is essential for the future of humanity, as we continue to explore and potentially colonize other planets.Overall, the universe is a topic that never fails to inspire awe and wonder. Whether you're a casual stargazeror a professional astronomer, there is always something new and exciting to learn.中文：宇宙是一个令人着迷的话题，数百年来一直吸引着人类。
DESY02-096ISSN0418-9833 July2002Search for Excited Electrons at HERAH1CollaborationAbstractA search for excited electron(e∗)production is described in which the electroweak decayse∗→eγ,e∗→eZ and e∗→νW are considered.The data used correspond to anintegrated luminosity of120pb−1taken in e±p collisions from1994to2000with the H1detector at HERA at centre-of-mass energies of300and318GeV.No evidence for a signalis found.Mass dependent exclusion limits are derived for the ratio of the couplings to thecompositeness scale,f/Λ.These limits extend the excluded region to higher masses thanhas been possible in previous direct searches for excited electrons.To be submitted toPhysics Letters BC.Adloff33,V.Andreev24,B.Andrieu27,T.Anthonis4,A.Astvatsatourov35,A.Babaev23,J.B¨a hr35,P.Baranov24,E.Barrelet28,W.Bartel10,S.Baumgartner36,J.Becker37,M.Beckingham21,A.Beglarian34,O.Behnke13,A.Belousov24,Ch.Berger1,T.Berndt14,ot26,J.B¨o hme10,V.Boudry27,W.Braunschweig1,V.Brisson26,H.-B.Br¨o ker2,D.P.Brown10,D.Bruncko16,F.W.B¨u sser11,A.Bunyatyan12,34,A.Burrage18,G.Buschhorn25, L.Bystritskaya23,A.J.Campbell10,S.Caron1,F.Cassol-Brunner22,D.Clarke5,C.Collard4, J.G.Contreras7,41,Y.R.Coppens3,J.A.Coughlan5,M.-C.Cousinou22,B.E.Cox21,G.Cozzika9,J.Cvach29,J.B.Dainton18,W.D.Dau15,K.Daum33,39,M.Davidsson20,B.Delcourt26,N.Delerue22,R.Demirchyan34,A.De Roeck10,43,E.A.De Wolf4,C.Diaconu22,J.Dingfelder13,P.Dixon19,V.Dodonov12,J.D.Dowell3,A.Droutskoi23,A.Dubak25,C.Duprel2,G.Eckerlin10,D.Eckstein35,V.Efremenko23,S.Egli32,R.Eichler32, F.Eisele13,E.Eisenhandler19,M.Ellerbrock13,E.Elsen10,M.Erdmann10,40,e,W.Erdmann36, P.J.W.Faulkner3,L.Favart4,A.Fedotov23,R.Felst10,J.Ferencei10,S.Ferron27,M.Fleischer10,P.Fleischmann10,Y.H.Fleming3,G.Fl¨u gge2,A.Fomenko24,I.Foresti37,J.Form´a nek30,G.Franke10,G.Frising1,E.Gabathuler18,K.Gabathuler32,J.Garvey3,J.Gassner32,J.Gayler10,R.Gerhards10,C.Gerlich13,S.Ghazaryan4,34,L.Goerlich6,N.Gogitidze24,C.Grab36,V.Grabski34,H.Gr¨a ssler2,T.Greenshaw18,G.Grindhammer25, T.Hadig13,D.Haidt10,L.Hajduk6,J.Haller13,B.Heinemann18,G.Heinzelmann11,R.C.W.Henderson17,S.Hengstmann37,H.Henschel35,R.Heremans4,G.Herrera7,44,I.Herynek29,M.Hildebrandt37,M.Hilgers36,K.H.Hiller35,J.Hladk´y29,P.H¨o ting2,D.Hoffmann22,R.Horisberger32,A.Hovhannisyan34,S.Hurling10,M.Ibbotson21,C¸.˙Is¸sever7, M.Jacquet26,M.Jaffre26,L.Janauschek25,X.Janssen4,V.Jemanov11,L.J¨o nsson20,C.Johnson3,D.P.Johnson4,M.A.S.Jones18,H.Jung20,10,D.Kant19,M.Kapichine8,M.Karlsson20,O.Karschnick11,J.Katzy10,F.Keil14,N.Keller37,J.Kennedy18,I.R.Kenyon3, C.Kiesling25,P.Kjellberg20,M.Klein35,C.Kleinwort10,T.Kluge1,G.Knies10,B.Koblitz25, S.D.Kolya21,V.Korbel10,P.Kostka35,S.K.Kotelnikov24,R.Koutouev12,A.Koutov8,J.Kroseberg37,K.Kr¨u ger10,T.Kuhr11,mb3,ndon19,nge35,ˇs toviˇc ka35,30,ycock18,E.Lebailly26,A.Lebedev24,B.Leißner1,R.Lemrani10,V.Lendermann10,S.Levonian10,B.List36,E.Lobodzinska10,6,B.Lobodzinski6,10,A.Loginov23,N.Loktionova24,V.Lubimov23,S.L¨u ders37,D.L¨u ke7,10,L.Lytkin12,N.Malden21,E.Malinovski24,S.Mangano36,R.Maraˇc ek25,P.Marage4,J.Marks13,R.Marshall21,H.-U.Martyn1,J.Martyniak6,S.J.Maxfield18,D.Meer36,A.Mehta18,K.Meier14,A.B.Meyer11,H.Meyer33,J.Meyer10,S.Michine24,S.Mikocki6,stead18, S.Mohrdieck11,M.N.Mondragon7,F.Moreau27,A.Morozov8,J.V.Morris5,K.M¨u ller37, P.Mur´ın16,42,V.Nagovizin23,B.Naroska11,J.Naumann7,Th.Naumann35,P.R.Newman3, F.Niebergall11,C.Niebuhr10,O.Nix14,G.Nowak6,M.Nozicka30,B.Olivier10,J.E.Olsson10, D.Ozerov23,V.Panassik8,C.Pascaud26,G.D.Patel18,M.Peez22,E.Perez9,A.Petrukhin35, J.P.Phillips18,D.Pitzl10,R.P¨o schl26,I.Potachnikova12,B.Povh12,J.Rauschenberger11,P.Reimer29,B.Reisert25,C.Risler25,E.Rizvi3,P.Robmann37,R.Roosen4,A.Rostovtsev23, S.Rusakov24,K.Rybicki6,D.P.C.Sankey5,S.Sch¨a tzel13,J.Scheins10,F.-P.Schilling10,P.Schleper10,D.Schmidt33,D.Schmidt10,S.Schmidt25,S.Schmitt10,M.Schneider22,L.Schoeffel9,A.Sch¨o ning36,T.Sch¨o rner25,V.Schr¨o der10,H.-C.Schultz-Coulon7,C.Schwanenberger10,K.Sedl´a k29,F.Sefkow37,V.Shekelyan25,I.Sheviakov24,1L.N.Shtarkov24,Y.Sirois27,T.Sloan17,P.Smirnov24,Y.Soloviev24,D.South21,V.Spaskov8, A.Specka27,H.Spitzer11,R.Stamen7,B.Stella31,J.Stiewe14,I.Strauch10,U.Straumann37, S.Tchetchelnitski23,G.Thompson19,P.D.Thompson3,F.Tomasz14,D.Traynor19,P.Tru¨o l37, G.Tsipolitis10,38,I.Tsurin35,J.Turnau6,J.E.Turney19,E.Tzamariudaki25,A.Uraev23,M.Urban37,ik24,S.Valk´a r30,A.Valk´a rov´a30,C.Vall´e e22,P.Van Mechelen4,A.Vargas Trevino7,S.Vassiliev8,Y.Vazdik24,C.Veelken18,A.Vest1,A.Vichnevski8,K.Wacker7,J.Wagner10,R.Wallny37,B.Waugh21,G.Weber11,D.Wegener7,C.Werner13,N.Werner37, M.Wessels1,G.White17,S.Wiesand33,T.Wilksen10,M.Winde35,G.-G.Winter10,Ch.Wissing7,M.Wobisch10,E.-E.Woehrling3,E.W¨u nsch10,A.C.Wyatt21,J.ˇZ´aˇc ek30,J.Z´a leˇs´a k30,Z.Zhang26,A.Zhokin23,F.Zomer26,and M.zur Nedden251I.Physikalisches Institut der RWTH,Aachen,Germany a2III.Physikalisches Institut der RWTH,Aachen,Germany a3School of Physics and Space Research,University of Birmingham,Birmingham,UK b4Inter-University Institute for High Energies ULB-VUB,Brussels;Universiteit Antwerpen (UIA),Antwerpen;Belgium c5Rutherford Appleton Laboratory,Chilton,Didcot,UK b6Institute for Nuclear Physics,Cracow,Poland d7Institut f¨u r Physik,Universit¨a t Dortmund,Dortmund,Germany a8Joint Institute for Nuclear Research,Dubna,Russia9CEA,DSM/DAPNIA,CE-Saclay,Gif-sur-Yvette,France10DESY,Hamburg,Germany11Institut f¨u r Experimentalphysik,Universit¨a t Hamburg,Hamburg,Germany a12Max-Planck-Institut f¨u r Kernphysik,Heidelberg,Germany13Physikalisches Institut,Universit¨a t Heidelberg,Heidelberg,Germany a14Kirchhoff-Institut f¨u r Physik,Universit¨a t Heidelberg,Heidelberg,Germany a15Institut f¨u r experimentelle und Angewandte Physik,Universit¨a t Kiel,Kiel,Germany16Institute of Experimental Physics,Slovak Academy of Sciences,Koˇs ice,Slovak Republic e,f 17School of Physics and Chemistry,University of Lancaster,Lancaster,UK b18Department of Physics,University of Liverpool,Liverpool,UK b19Queen Mary and Westfield College,London,UK b20Physics Department,University of Lund,Lund,Sweden g21Physics Department,University of Manchester,Manchester,UK b22CPPM,CNRS/IN2P3-Univ Mediterranee,Marseille-France23Institute for Theoretical and Experimental Physics,Moscow,Russia l24Lebedev Physical Institute,Moscow,Russia e25Max-Planck-Institut f¨u r Physik,M¨u nchen,Germany26LAL,Universit´e de Paris-Sud,IN2P3-CNRS,Orsay,France27LPNHE,Ecole Polytechnique,IN2P3-CNRS,Palaiseau,France28LPNHE,Universit´e s Paris VI and VII,IN2P3-CNRS,Paris,France29Institute of Physics,Academy of Sciences of the Czech Republic,Praha,Czech Republic e,i 30Faculty of Mathematics and Physics,Charles University,Praha,Czech Republic e,i31Dipartimento di Fisica Universit`a di Roma Tre and INFN Roma3,Roma,Italy232Paul Scherrer Institut,Villigen,Switzerland33Fachbereich Physik,Bergische Universit¨a t Gesamthochschule Wuppertal,Wuppertal, Germany34Yerevan Physics Institute,Yerevan,Armenia35DESY,Zeuthen,Germany36Institut f¨u r Teilchenphysik,ETH,Z¨u rich,Switzerland j37Physik-Institut der Universit¨a t Z¨u rich,Z¨u rich,Switzerland j38Also at Physics Department,National Technical University,Zografou Campus,GR-15773 Athens,Greece39Also at Rechenzentrum,Bergische Universit¨a t Gesamthochschule Wuppertal,Germany40Also at Institut f¨u r Experimentelle Kernphysik,Universit¨a t Karlsruhe,Karlsruhe,Germany 41Also at Dept.Fis.Ap.CINVESTAV,M´e rida,Yucat´a n,M´e xico k42Also at University of P.J.ˇSaf´a rik,Koˇs ice,Slovak Republic43Also at CERN,Geneva,Switzerland44Also at Dept.Fis.CINVESTAV,M´e xico City,M´e xico ka Supported by the Bundesministerium f¨u r Bildung und Forschung,FRG,under contract numbers05H11GUA/1,05H11PAA/1,05H11PAB/9,05H11PEA/6,05H11VHA/7and 05H11VHB/5b Supported by the UK Particle Physics and Astronomy Research Council,and formerly by the UK Science and Engineering Research Councilc Supported by FNRS-FWO-Vlaanderen,IISN-IIKW and IWTd Partially Supported by the Polish State Committee for Scientific Research,grant no.2P0310318and SPUB/DESY/P03/DZ-1/99and by the German Bundesministerium f¨u r Bildung und Forschunge Supported by the Deutsche Forschungsgemeinschaftf Supported by VEGA SR grant no.2/1169/2001g Supported by the Swedish Natural Science Research Councili Supported by the Ministry of Education of the Czech Republic under the projectsINGO-LA116/2000and LN00A006,by GAUK grant no173/2000j Supported by the Swiss National Science Foundationk Supported by CONACyTl Partially Supported by Russian Foundation for Basic Research,grant no.00-15-965843Among the unexplained features of the Standard Model(SM)of particle physics is the exis-tence of three distinct generations of fermions and the hierarchy of their masses.One possible explanation for this is fermion substructure,with the constituents of the known fermions being strongly bound together by a new,as yet undiscovered force[1,2].A natural consequence of these models would be the existence of excited states of the known leptons and quarks.Assum-ing a compositeness scale in the TeV region,one would naively expect that the excited fermions have masses in the same energy region.However,the dynamics of the constituent level are un-known,so the lowest excited states could have masses of the order of only a few hundred GeV. Electron1-proton interactions at very high energies provide an excellent environment in which to search for excited fermions of thefirst generation.These excited electrons(e∗)could be singly produced through t-channelγand Z boson exchange.Their production cross-section and par-tial decay widths have been calculated using an effective Lagrangian[3,4]which depends on a compositeness mass scaleΛand on weight factors f and f′describing the relative coupling strengths of the excited lepton to the SU(2)L and U(1)Y gauge bosons,respectively.In this model the excited electron can decay to an electron or a neutrino via the radiation of a gauge boson(γ,W,Z)with branching ratios determined by the e∗mass and the coupling parameters f and f′.In most analyses[5–7]the assumption is made that these coupling parameters are of comparable strength and only the relationships f=+f′or f=−f′are considered.If a relationship between f and f′is assumed,the production cross-section and partial decay widths depend on two parameters only,namely the e∗mass and the ratio f/Λ.In this paper excited electrons are searched for in three samples of data taken by the H1 experiment from1994to2000with a total integrated luminosity of120pb−1.Thefirst sample consists of e+p data accumulated from1994to1997at positron and proton beam energies of27.5GeV and820GeV respectively,and corresponds to an integrated luminosity of37pb−1.A search for excited electrons using this sample of data has been previously published[8].The strategy for the selection of events has been modified from the procedures described in[8]to optimize the sensitivity to higher e∗masses.The two other samples were taken from1998 to2000with an electron or positron beam energy of27.5GeV and a proton beam energy of 920GeV.The integrated luminosities of the e−p and e+p samples are15pb−1and68pb−1, pared to previous H1results[8]the analysis presented here benefits from an increase in luminosity by a factor of more than three and an increase of the centre-of-mass energy from300GeV to318GeV.We search for all electroweak decays e∗→eγ,e∗→eZ and e∗→νW,considering the subsequent Z and W hadronic decay modes only.This leads tofinal states containing an electron and a photon,an electron and jets or jets with missing transverse energy induced by the neutrinos escaping from the detector.The Standard Model backgrounds which could mimic such signatures are neutral current Deep Inelastic Scattering(NC DIS),charged current Deep Inelastic Scattering(CC DIS),QED Compton scattering(or Wide Angle Bremsstrahlung W AB),photoproduction processes(γp)and lepton pair production via the two photon fusion process(γγ).The determination of the contribution of NC DIS processes is performed using two MonteCarlo samples which employ different models of QCD radiation.Thefirst was produced withthe DJANGO[9]event generator which includes QEDfirst order radiative corrections based onHERACLES[10].QCD radiation is implemented using ARIADNE[11]based on the ColourDipole Model[12].This sample,with an integrated luminosity of more than10times the exper-imental luminosity,is chosen to estimate the NC DIS contribution in the e∗→eγanalysis.The second sample was generated with the program RAPGAP[13],in which QEDfirst order radia-tive corrections are implemented as described above.RAPGAP includes the leading order QCDmatrix element and higher order radiative corrections are modelled by leading-log parton show-ers.This sample is used to determine potential NC DIS background in the e∗→νW֒→q¯q and e∗→eZ֒→q¯q searches,as RAPGAP describes better this particular phase space domain[8]. For both samples the parton densities in the proton are taken from the MRST[14]parametriza-tion which includes constraints from DIS measurements at HERA up to squared momentum transfers Q2=5000GeV2[15–18].Hadronisation is performed in the Lund string fragmenta-tion scheme using JETSET[19].The modelling of the CC DIS process is performed using the DJANGO program with MRST structure functions.While inelastic W AB is treated using the DJANGO generator,elastic and quasi-elastic W AB is simulated with the W ABGEN[20]event generator.Direct and resolvedγp processes including prompt photon production are generated with the PYTHIA[21]event generator.Finally theγγprocess is produced using the LPAIR generator[22].For the calculation of the e∗production cross-section and to determine the efficiencies,events have been generated with the COMPOS[23]generator based on the cross-section for-mulae given in reference[3]and the partial decay widths stated in reference[4].Initial stateradiation of a photon from the incoming electron is included.This generator uses the narrowwidth approximation(NW A)for the calculation of the production cross section and takes intoaccount the natural width for the e∗decay.For all values of f/Λrelevant to this analysis thisassumption is valid even at high e∗masses where the natural width of the e∗is of the order ofthe experimental resolution.To give an example,for M e∗=250GeV this resolution is equal to7GeV,10GeV,and12GeV for the eγ,eZ andνW decay modes,respectively.All Monte Carlo samples are subjected to a detailed simulation of the response of the H1detector.The detector components of the H1experiment[24]most relevant for this analysis arebriefly described in the following.Surrounding the interaction region is a system of drift andproportional chambers which covers the polar angle2range7◦<θ<176◦.The tracking sys-tem is surrounded by afinely segmented liquid argon(LAr)calorimeter covering the polar angle√range4◦<θ<154◦[25]with energy resolutions ofσE/E≃12%/E⊕2%for hadrons,obtained in test beam measurements[26,27].The tracking system and calorimeters are surrounded by a superconducting solenoid and an iron yoke instrumented with streamer tubes.Backgrounds not related to e+p or e−p collisions are rejected by requiring that a primary interaction vertex be reconstructed within±35cm of the nominal vertex position,by usingfilters based on the event topology and by requiring an event time which is consistent with the interaction time.Electromagnetic clusters are required to havemore than95%of their energy in the electromagnetic part of the calorimeter and to be isolated from other particles[28].They are further differentiated into electron and photon candidates using the tracking chambers.Jets with a minimum transverse momentum of5GeV are recon-structed from the hadronicfinal state using a cone algorithm adapted from the LUCELL schemein the JETSET package[19].Missing transverse energy(E misst )is reconstructed using the vec-tor sum of energy depositions in the calorimeter cells.The analysis presented in this paper is described extensively in[29].The e∗→eγchannel is characterized by two electromagnetic clusters in thefinal state. The main sources of background are the W AB process,NC DIS with photon radiation or a high energyπ0in a jet and the production of electron pairs viaγγfusion.Candidate events are selected with two electromagnetic clusters in the LAr calorimeter of transverse energy greater than20GeV and15GeV,respectively,and with a polar angle between0.1and2.2radians. The sum of the energies of the two clusters has to be greater than100GeV.If this sum is below 200GeV,the background is further suppressed by rejecting events with a total transverse energy of the two electromagnetic clusters lower than75GeV or with more than two tracks spatially associated to one of the clusters.The numbers of events passing the analysis cuts for the SM background processes and for the data in each of the three samples are given in Table1.About half of the background originates from NC DIS events with most of the remainder being due to W AB events.The efficiency for selecting the signal varies from85%for an e∗mass of150GeV to72%for an e∗mass of250GeV.As in all other channels the efficiencies are derived using samples of1000e∗events generated at different e∗masses.The various sources of systematic error are discussed later.Distributions of the invariant mass of the candidate electron-photon pairs of the three data samples together and for the SM expectation are shown in Fig.1a.Sample e−p920GeVChannel SM background SM background SM background e∗→eγ7.2±1.0±0.1 4.0±0.7±0.215.6±1.7±0.4 e∗→eZ֒→q¯q7.1±2.1±2.8 5.6±0.4±1.225.3±1.9±5.5 e∗→νW֒→q¯q 2.4±0.2±0.7 3.9±0.2±0.7 6.1±0.4±1.5 Table1:Number of candidate events observed in the three decay channels with the correspond-ing SM expectation and the uncertainties on the expectation(statistical and systematic error).The e∗→eZ֒→q¯q channel is characterized by an electromagnetic cluster with an associated track and two high transverse energy jets.The analysis for this channel uses a sample of events with at least two jets with a transverse energy above17GeV and16GeV,respectively,and an electron candidate with a transverse energy E e t>20GeV.These two jets and the electron must have polar angles smaller than2.2radians.Furthermore,to avoid possible double counting of events from the e∗→eγchannel,events with two electromagnetic clusters with transverse energies above10GeV and a total energy of the two clusters greater than100GeV are removed. The main SM contribution is NC DIS as photoproduction events do not yield a significant rate of electron candidates with large E e t.For20GeV<E e t<65GeV,a cut is made on the602468101214161820invariant mass (GeV)e v e n t s0510152025invariant mass (GeV)e v e n t s 012345678910invariant mass (GeV)e v e n t s Figure 1:Invariant mass spectra of candidate (a)eγpairs for the e ∗→eγanalysis,(b)elec-tron and two jets for the e ∗→eZ analysis and (c)neutrino and two jets for the e ∗→νW anal-ysis.Solid points correspond to the data and the histogram to the total expectation from different SM processes.electron polar angle.This ranges from θe <1.35for E e t =20GeV to θe <2.2radians for E e t =65GeV and depends linearly on E e t .The dijet invariant mass has to be in the range −15<M jj −M Z <7GeV .If there are more than two jets,the pair with invariant mass closest to the nominal Z boson mass is chosen as the Z candidate.The two jets chosen are ordered such that E jet 1t >E jet 2t .In many SM events the direction of jet 2is close to the proton direction.To ensure that this jet is well measured,an additional cut on its polar angle,θjet 2>0.2radians,7is applied if its transverse momentum is lower than30GeV.For an electron transverse energy 65GeV<E e t<85GeV two jets with an invariant mass M jj>M Z−30GeV are required. At very high transverse energy,E e t>85GeV,the contribution from NC DIS is very low and no further cuts on M jj are needed.The number of events which remain in the data after these cuts are summarized in Table1and compared with the expected SM contribution(mostly NC DIS events).The efficiency for selecting the signal varies from44%for an e∗mass of150GeV to 62%for an e∗mass of250GeV.Distributions of the invariant mass of the electron and the two jets are shown in Fig.1b for data and for the SM expectation.The e∗→νW֒→q¯q channel is characterized by two jets and missing transverse energy E miss t. The main background originates from CC DIS events with a moderate contribution from photo-production,whereas the NC DIS contribution is suppressed for large E misst .The analysis startsfrom a sample of events with at least two jets with transverse energies above17GeV and16GeV,missing transverse energy E misst >20GeV and no isolated electromagnetic cluster withtransverse energy above10GeV.The jets must have a polar angle below2.2radians.Jets in which the most energetic track enters the boundary region between two calorimeter modules and central jets(θ>0.5radians)are required to contain more than two tracks.This cut re-moves NC DIS events in which the scattered electron is misidentified as a jet.Only events with S=V apevents in a mass interval that varies with the width of the expected signal.At M e ∗=150GeV ,a width of the mass interval of 30GeV is chosen for the e ∗→eγdecay mode and 60GeV is chosen for the decay channels with two jets.Systematic uncertainties are taken into account as in [8].The limits on the product of the e ∗production cross-section and the decay branching ratio are shown in Fig.2.As stated in the introduction,most experiments give f/Λlimits under the assumptions f =+f ′and f =−f ′.The H1limits for each decay channel and after combi-nation of all decay channels are given as a function of the e ∗mass in Fig.3a,for the assumption f =+f ′.With this hypothesis the main contribution comes from the e ∗→eγchannel.The values of the limits for f/Λvary between 5×10−4and 10−2GeV −1for an e ∗mass ranging from 130GeV to 275GeV .These results improve significantly the previously published H1limits for e +p [8]collisions.The LEP experiments [5,6]and the ZEUS collaboration [7]have also reported on excited electron searches.Their limits are shown in Fig.3b.The LEP 2experiments have shown results in two mass domains.In direct searches for excited electrons limits up to a mass of about 200GeV are given.Above 200GeV their results are derived from indirect searches only.The H1limit extends the excluded region to higher masses than reached in previous direct searches.Figure 2:Upper limits at 95%confi-dence level on the product of the pro-duction cross-section σand the decaybranching ratio BR for excited elec-trons e ∗in the various electroweakdecay channels,e ∗→eγ(dashed line),e ∗→eZ ֒→q ¯q (dotted-dashedline)and e ∗→νW ֒→q ¯q (dotted line)as a function of the excited electronmass.The signal efficiencies used tocompute these limits have been deter-mined with events generated under theassumption f =+f ′.1010110e * mass (GeV)σ*B R (p b )More generally,limits on f/Λas a function of f ′/f are shown in Fig.4for three e ∗masses (150,200and 250GeV ).It is worth noting that excited electrons have vanishing electromag-netic coupling for f =−f ′.In this case the e ∗is produced through pure Z boson exchange.As a consequence the production cross-section for excited electrons at HERA is much smaller in the f =−f ′case than in the f =+f ′case.For e ∗masses between 150and 250GeV the ratio910101010e* mass (GeV)f /Λ (G e V -1)10101010e* mass (GeV)f /Λ (G e V -1)Figure 3:Exclusion limits on the coupling f/Λat 95%confidence level as a function of the mass of excited electrons with the assumption f =+f ′.(a)Limit for each decay channele ∗→eγ(dashed line),e ∗→eZ ֒→q ¯q (thick dotted-dashed line),e ∗→νW ֒→q ¯q (dotted line)and for the combination of the three channels (full line).It must be noted that a part of the data included in the present result were used to obtain the previous H1limit [8].(b)Comparison of this analysis with ZEUS results [7](dashed line)and LEP 2results on direct searches [5](dotted-dashed line)and on indirect searches [6](dotted line).of the cross-sections for f =+f ′and f =−f ′varies between 170and 900.For high e ∗masses and some values of the couplings,no limits are given because the natural width of the e ∗would become extremely large.In summary,a search for excited electron production was performed using all the e +p and e −p data accumulated by H1between 1994and 2000.No indication of a signal was found.New limits have been established as a function of the couplings and the excited electron mass for the conventional relationship between the couplings f =+f ′.The dependence of the f/Λlimit on the ratio f ′/f has been shown for the first time at HERA.The data presented here restrict excited electrons to higher mass values than has been possible previously in direct searches.We are grateful to the HERA machine group whose outstanding efforts have made and continue to make this experiment possible.We thank the engineers and technicians for their work in constructing and now maintaining the H1detector,our funding agencies for financial support,the DESY technical staff for continual assistance and the DESY directorate for the hospitality which they extend to the non-DESY members of the collaboration.10Figure 4:Exclusion lim-its on the coupling f/Λat 95%confidence level as a function of the ratio f ′/f for three different masses of the e ∗:150GeV (full line),200GeV (dotted line)and 250GeV (dashed line).10101010f //ff / Λ (G e V -1)References[1]H.Harari,Phys.Rep.104(1984)159.[2]F.Boudjema,A.Djouadi and J.L.Kneur,Z.Phys.C 57(1993)425.[3]K.Hagiwara,D.Zeppenfeld and S.Komamiya,Z.Phys.C 29(1985)115.[4]U.Baur,M.Spira and P.M.Zerwas,Phys.Rev.D 42(1990)815.[5]G.Abbiendi et al.[OPAL Collaboration],CERN-EP/2002-043,arXiv:hep-ex/0206061.Submitted to Phys.Lett.B [6]P.Abreu et al.[DELPHI Collaboration],Eur.Phys.J.C 8(1999)41[hep-ex/9811005].[7]S.Chekanov et al.[ZEUS Collaboration],DESY-01-132arXiv:hep-ex/0109018.[8]C.Adloff et al.,[H1Collaboration],Eur.Phys.J.C 17(2000)567[hep-ex/0007035].[9]G.A.Schuler and H.Spiesberger,in:Proceedings of Physics at HERA ,Hamburg 1991,V ol.3,pp.1419-1432.[10]A.Kwiatkowski,H.Spiesberger and H.J.M¨o hring,mun.69(1992)155.11[11]L.L¨o nnblad,mun.71(1992)15.[12]B.Andersson,G.Gustafson,L.L¨o nnblad and U.Pettersson,Z.Phys.C43(1989)625.[13]H.Jung,mun.86(1995)147.[14]A.D.Martin,R.G.Roberts,W.J.Stirling and R.S.Thorne,Eur.Phys.J.C4(1998)463.[hep-ph/9803445].[15]S.Aid et al.,[H1Collaboration],Nucl.Phys.B470(1996)3[hep-ex/9603004].[16]C.Adloff et al.,[H1Collaboration],Nucl.Phys.B497(1997)3[hep-ex/9703012].[17]M.Derrick et al.,[ZEUS Collaboration],Z.Phys.C69(1996)607[hep-ex/9510009].[18]M.Derrick et al.,[ZEUS Collaboration],Z.Phys.C72(1996)399[hep-ex/9607002].[19]T.Sj¨o strand,hep-ph/9508391,LU-TP-95-20,CERN-TH-7112-93-REV,August1995.[20]C.Berger and P.Kandel,Proceedings of the Workshop Monte Carlo generators for HERAPhysics,Hamburg1998-1999,pp.596-600,[hep-ph/9906541].[21]T.Sj¨o strand,mun.82(1994)74.[22]S.P.Baranov,O.D¨u nger,H.Shooshtari and J.A.Vermaseren,Proceedings of Physics atHERA,Hamburg1991,vol.3,pp.1478-1482.[23]T.K¨o hler,Proceedings of Physics at HERA,Hamburg1991,vol.3,pp.1526-1541.[24]I.Abt et al.,[H1Collaboration],Nucl.Instrum.Meth.A386(1997)310;ibid.348.[25]B.Andrieu et 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TPO63阅读-2Structure and Composition of Comets原文 (1)译文 (3)题目 (4)答案 (7)背景知识 (8)原文Structure and Composition of Comets①Astronomers now have a fairly good idea of what a comet really is.When it is far from the Sun,it is a very small object only a few kilometers across.It consists mainly of ices(water,methane,ammonia)with bits of dust embedded in it-a kind of dirty ice ball.As it approaches the Sun,radiation from the Sun vaporizes the icy matter and releases some of the dust.This forms a gigantic halo around the ice ball. This halo-called the coma extends out tens of thousands of kilometers from the icy core,which is the nucleus of the comet.Sunlight reflected off the dust particles makes the coma visible to observers on Earth.Ultraviolet radiation from the Sun breaks down the vapor molecules into their constituents.These components can be excited by absorbing radiation from the Sun.In returning to lower-energy states, the excited atoms and ions emit light,contributing to the luminosity of the coma.②When the comet gets even closer to the Sun,one of its most spectacular parts begins to form-the tail.Actually,there are two kinds of tails:the dust tail and the ion tail.The dust tail is produced by the light from the Sun reflecting off the dust particles in the coma.A photon carries momentum.In bouncing off a dust particle, it imparts a tiny,but perceptible,momentum change to the dust particle,driving it away from the coma.As the comet sweeps along its orbit,it leaves a curving trail of dust behind in its path.This visible dust tail can extend for tens or hundreds of millions of kilometers out from the nucleus.The dust tail is characterized by its gently curving shape and its yellowish color.③A different mechanism is responsible for the ion tail.Near the Sun,ultraviolet radiation from the Sun(solar wind)ionizes and excites the atoms in the coma.Asthe solar wind sweeps through the coma,the high-velocity charged particles of the solar wind interact with the electrically charged excited ions in the coma,driving them away from the head of the comet.In returning to lower-energy states,these excited ions emit photons and form a luminous,bluish-colored tail extending out from the comet directly away from the Sun.Since both kinds of tails are produced by radiation streaming out from the Sun,they extend out from the coma in the general direction away from the Sun.A comet may exhibit several tails of each kind.④Although the nucleus is of the order of a few kilometers in size,the diameter of the coma may be tens or hundreds of thousands of kilometers;the tails typically extend out tens or hundreds of millions of kilometers away from the coma.⑤A comet leaves a trail of matter behind it as it moves through the inner solar system.Some of this debris may get strewn across Earth's orbit around the Sun. When Earth passes through this part of its annual path,it sweeps through the dust trail.The particles enter Earth's atmosphere at high velocity.The air friction can cause one of these bits of matter to produce a brief streak of light as it burns up in the atmosphere.⑥Since a comet loses matter on each pass by the Sun,eventually it will be depleted to the point where it is no longer ets that approach the Sun have finite lifetimes.Given the typical sizes of comets and the typical rates at which they lose matter,astronomers have concluded that the lifetimes of comets with orbits that bring them near enough to the Sun to be seen from Earth are very much shorter than the age of the solar system.Where do the new comets come from to replace the old ones that dissipate and vanish from view?⑦Dutch astronomer Jan Oort proposed that a giant cloud of matter left over from the formation of the solar system surrounds the Sun and extends out to about 50,000astronomical units.This cloud contains large chunks of matter like the nuclei of comets.The gravitational influence of a passing star can be sufficient to perturb the orbit of one of these chunks to send it toward the inner solar system and bring it near the Sun.译文彗星的结构和组成①天文学家现在对彗星的真正含义有了相当好的了解。
初三英语太空探索与宇宙科学阅读理解25题1<背景文章>Mars Exploration: Past, Present and FutureMars has always fascinated scientists and space enthusiasts alike. In the past, several missions have been launched to explore the Red Planet. The Viking missions in the 1970s were among the first to land on Mars and conduct scientific experiments.These early missions provided valuable insights into the Martian atmosphere, surface features, and potential for life. Since then, many more missions have been sent to Mars. The Mars Reconnaissance Orbiter, for example, has been studying the planet from orbit, mapping its surface and looking for signs of water.Current research on Mars is focused on understanding its geology, climate, and potential habitability. Scientists are also looking for evidence of past or present life on Mars. Future plans include sending humans to Mars. This would be a major milestone in space exploration.However, there are many challenges to overcome before humans can set foot on Mars. These include the long journey time, radiation exposure, and the need for sustainable life support systems.1. The Viking missions were launched in ____.A. the 1960sB. the 1970sC. the 1980sD. the 1990s答案：B。
extremely large的单词-回复"Extremely Large" is an intriguing topic that encompasses a wide range of aspects. In this article, we will explore various aspects related to extreme largeness, touching upon subjects such as celestial bodies, infrastructure, artworks, and human achievements. Let's dive into the astonishing world of the extraordinarily immense.To begin with, one cannot discuss extreme largeness without mentioning the universe. The universe, with its countless galaxies, stars, and planets, is an unimaginably vast expanse. Scientists estimate that the observable universe spans approximately 93 billion light-years in diameter. This astronomical size leaves one awe-inspired, questioning humanity's place in such a colossal cosmos.Zooming in on celestial objects within the universe, we encounter supermassive black holes. Found at the centers of galaxies, these monstrous entities possess incredible mass, hence the term "supermassive." One such example is the black hole in the M87 galaxy, which was captured by the Event Horizon Telescope in 2019. This black hole has a mass equivalent to 6.5 billion times that of oursun, an astounding size that defies comprehension.Shifting our focus to a terrestrial scenario, infrastructure projects often showcase extreme largeness. One notable example is the Great Wall of China. Spanning over 13,000 miles, this architectural marvel is an enduring symbol of human grandeur and dedication. Built for defensive purposes, the Great Wall exemplifies the colossal efforts undertaken by ancient civilizations.Another striking feat of engineering is the Three Gorges Dam in China. Completed in 2006, it is the world's largest hydroelectric power station. The dam stretches over 1.4 miles in length and stands approximately 600 feet tall. Its construction required the relocation of millions of people and the taming of the mighty Yangtze River. This project stands as a testament to humanity's ability to reshape the natural world on an unprecedented scale.Transitioning from infrastructure to art, we encounter theawe-inspiring dimensions found in various artistic creations. The Sistine Chapel's frescoes by Michelangelo provide an excellent example of artistry on an overwhelmingly large scale. Covering an area of approximately 5,000 square feet, the intricate details andvibrant colors of these frescoes are truly breathtaking.Similarly, the work of Christo and Jeanne-Claude, renowned for their large-scale environmental installations, captivates viewers through sheer size and audacity. One of their most famous projects was "The Floating Piers" on Italy's Lake Iseo. This installation consisted of bright orange walkways extending over three kilometers, inviting visitors to experience the sensation of walking on water. The expansiveness of their installations challenges our perception of physical boundaries and encourages contemplation of the relationship between art and its surroundings.Lastly, human achievements themselves can be seen as manifestations of extreme largeness. From monumental breakthroughs in scientific research to record-breaking athletic feats, individuals continue to push the boundaries of what is considered possible. Think of explorers like Edmund Hillary and Tenzing Norgay, whose summiting of Mount Everest in 1953 marked a momentous achievement in human history. Their perseverance and determination against the immense scale of Earth's highest peak inspire awe and admiration.In conclusion, extreme largeness manifests in various forms throughout our universe and human creations. From themind-boggling expanses of the cosmos to the monumental feats of engineering, art, and human accomplishments, we are constantly confronted with the astonishment that comes with confronting the extraordinary. These examples remind us of the remarkable potential, ingenuity, and resilience of humanity when confronted with seemingly insurmountable scales. The exploration of extreme largeness challenges our perceptions, fuels our imaginations, and compels us to continually aspire towards greatness.。
武汉市2024 届高中毕业生二月调研考试英语试卷养成良好的答题习惯，是决定高考英语成败的决定性因素之一。
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命题&审题：武汉市教育科学研究院第一部分听力 ( 共两节，满分 3 0 分 )做题时，先将答案标在试卷上。
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1.What are the speakers probably doing?A.Discussing at work.B.Talking on phoneC.Driving on the way2.What will the man do next?A.Have a dessert.B.Pay the check.C.Ask for a beer.3.What do we know about the hamburger?A.It might go bad.B.It's good-lookingC.It looked funny4.What are the speakers mainly talking about?A.The sceneryB.The transport.C.The weather.5.How does the woman sound in the end?A.Glad.B.Surprised.C.Impatient.第二节(共15小题；每小题1.5分，满分22.5分)听下面5段对话或独白。
![[O II] as a tracer of current star formation](https://uimg.taocdn.com/708d8f1b964bcf84b9d57bc6.webp)
a r X i v :a s t r o -p h /0012485v 1 22 D e c 2000The Astrophysical Journal,000:000–000,2001(MS-52562-ApJ)Preprint typeset using L A T E X style emulateapj2[O II]AS A TRACER OF STAR FORMATION the[O ii]/Hαratio on luminosity.The NFGS sample consists of196nearby galax-ies,objectively selected from the CfA redshift catalog(CfA I,Huchra et al.1983)to span a large range of−14to−22in absolute B magnitude without mor-phological bias.The sample should therefore be rep-resentative of the galaxy population in the local uni-verse,subject only to the biases inherent in B selec-tion and the surface brightness limit of the Zwickycatalog.Our data include nuclear and integratedspectrophotometry(covering the range3550–7250at∼6˚A resolution),supplemented by U,B,R surfacephotometry from which we obtained total magni-tudes and colors.For the details of the galaxy se-lection and for the U,B,R photometry,we refer thereader to Jansen et al.(2000a);for a full descriptionof the spectrophotometric data we refer to Jansenet al.(2000b).Of the191normal(non-AGN dominated)galax-ies in the NFGS sample,141show Hαemission in their integrated spectra.We will concentrate,how-ever,on the118galaxies with HαEW≤−10˚A for which the[O ii]/Hαratios are reliable,and on the 85galaxies that also have EW(Hβ)≤−5˚A for which we can derive accurate Balmer decrements to cor-rect the observed emission linefluxes for reddening. Throughout the paper we correct observed emission linefluxes for Galactic extinction,estimated from the H i maps of Burstein&Heiles(1984)and listed in the RC3(de Vaucouleurs et al.1991).The wave-length dependence of the extinction is assumed to follow the optical interstellar extinction law of Nandy et al.(1975)(as tabulated in Seaton1979,but adopt-ing R V=A V/E(B−V)=3.1instead of3.2).Ob-served Balmer emission linefluxes have also been cor-rected for stellar absorption lines.We partially compensated for the stellar absorp-tion underlying the Hβemission by placing the limits of the measurement window well inside the absorp-tion trough,closely bracketing the emission line.We evaluated the residual absorption using the spectra of galaxies with no detectable emission.On average,an additional correction of1˚A(EW)was required.Sim-ilarly,for Hαwe found that a correction of1.5˚A was needed.After correction,afit to the data in a Hβversus Hαplot passes through the origin.Because we restrict our analysis to galaxies with moderate to strong emission lines,we are insensitive to the details of this procedure.This paper is organized as follows.In section2 we evaluate the range in the observed and reddening corrected[O ii]/Hαratio and its dependence on lumi-nosity,and we demonstrate the effect of differences in the excitation state of the interstellar medium(ISM). In§3we relate the observed[O ii]and Hαfluxes Fig.1—The logarithm of the ratio of the observed[O ii] and Hαemission linefluxes versus total absolute B magni-tude.Only data for the118galaxies with strong emission [EW(Hα)<−10˚A]are shown to ensure reliable emission line ratios.The plotting symbols are coded according to morpho-logical type,as indicated.Overlayed is a linear least-squares fit to the data points.The[O ii]/Hαratio decreases systemat-ically from∼1.5at M B=−14to∼0.3at M B=−21.to the ionizingflux and show that these results are consistent with previous studies.We briefly discuss the implications for the use of Hβas SFR tracer in §4.We discuss how to improve SFR estimates and present empirical corrections in§5.The implications for evolutionary studies are discussed in§6.We con-clude with a short summary(§7).2.VARIATION IN THE[O ii]/HαRATIOInfigure1we plot the ratio of the observed[O ii] and Hαemission linefluxes vs.total absolute B mag-nitude for the118galaxies with EW(Hα)<−10˚A. The Balmer emission linefluxes were corrected for stellar absorption,but neither Hαnor[O ii]are cor-rected for internal interstellar reddening.The ob-served[O ii]/Hαratio decreases systematically with increasing galaxy luminosity,from∼1.5at M B=−14 to∼0.3at M B=−21,but the range is large.At M B=−18,only a magnitude fainter than the char-acteristic absolute magnitude of the local luminos-ity function(M∗∼−19.2,de Lapparent,Geller,& Huchra1989;M∗∼−18.8,Marzke et al.1994),the observed[O ii]/Hαratios vary by a factor of∼7.JANSEN,FRANX,&FABRICANT3Fig.2—(a )Logarithm of the observed [O ii ]/H αratio versus total absolute B magnitude.Here and in the following panels we only include the 85galaxies with EW(H β)<−5˚A ,allowing us to measure the Balmer decrement,H α/H β,reliably.The plotting symbols are coded according to morphological type as in Fig.1.(b )Logarithm of the [O ii ]/H αratio after correction for interstellar reddening versus absolute B magnitude.The dependence on galaxy luminosity is greatly reduced after correction for reddening,and both the total scatter and the scatter around the best linear fit through the data has decreased.(c )Logarithm of the observed [O ii ]/H αratio versus color excess E(B −V ),determined from the observed Balmer decrement.The [O ii ]/H αratio decreases as the reddening increases.The line shows the relation expected for the adopted reddening curve.(d )Color excess E(B −V )versus absolute B rger reddening values tend to correspond to higher galaxy luminosities,although the range in E(B −V )at a given galaxy luminosity is large.A linear least-squares fit to the data points is overlayed.2.1.Effects of Reddening by DustTo evaluate the contribution of extinction to the variation in the [O ii ]/H αratio and to the ratio’s de-pendence on galaxy luminosity,we compute the color excess,E(B −V ),from the observed Balmer decre-ment,H α/H β.We assume an intrinsic ratio of 2.85(the Balmer decrement for case B recombination at T=104K and n e ∼102–104cm −3;Osterbrock 1989)and adopt the optical interstellar extinction law of Nandy et al.(1975)(as tabulated in Seaton 1979,but adopting R V =A V /E(B −V )=3.1instead of 3.2).This procedure results in a lower limit to the actual reddening,as the observed Balmer decrement will be4[O II]AS A TRACER OF STAR FORMATIONweighted to the regions of lowest line-of-sight extinc-tion(Kennicutt1998a).Other studies suggest,how-ever,that this approach gives a reasonable estimate of the extinction(e.g.,Calzetti,Kinney,&Storchi-Bergmann1994;Buat&Xu1996),except for the dustiest regions in a galaxy.Figure2a is the same asfigure1except that we include only the85galaxies with EW(Hβ)<−5˚A, where we could measure the Balmer decrement parison offigures1and2a indicates that exclusion of the galaxies with fainter Hβemission is unlikely to bias our discussion.Infigure2b we present reddening corrected ratios of the[O ii]and Hαemission linefluxes versus ab-solute B magnitude on the same scale asfigure2a. The dependence of[O ii]/Hαon galaxy luminosity de-creases markedly after correction for interstellar red-dening:the slope of a linear least-squaresfit to the data changes from0.087dex/mag to0.035dex/mag and both the total scatter and the scatter around the fit decrease from0.18to0.09dex and from0.12to 0.08dex1,respectively.This implies that more than half of the observed scatter in[O ii]/Hαmust be due to dust.The total variation in[O ii]/Hαdecreases from a factor∼7to∼3.Ratios of(observed)equivalent widths behave much like extinction correctedflux ratios,but their dependence on the stellar continuum introduces a de-pendence on the star formation history of the galaxy. If we use EW ratios rather than reddening corrected flux ratios infigure2b the scatter around the bestfit increases(0.11versus0.08dex)and the slope steep-ens slightly(0.043versus0.035dex/mag).To show the effect of reddening on the relative strengths of[O ii]and Hαmore directly,infigure2c we plot the logarithm of the observed[O ii]/Hαratio versus color excess E(B−V).Wefind a clear trend toward lower[O ii]/Hαratios in galaxies with larger interstellar reddening.This trend spans most of the total range in[O ii]/Hα.For reference we overlay the relation expected for the adopted reddening law,as-suming an intrinsic[O ii]/Hαratio of1(i.e.,fixing the zeropoint to log([O ii]/Hα)=0for E(B−V)=0). Although the data points do not exactly follow the expected relation,the correspondence is good.Infigure2d we plot color excess E(B−V)versus absolute B magnitude.More luminous galaxies tend to show more reddening than low luminosity galaxies. The scatter on this trend is very large,however. Thesefigures show that galaxy luminosity,internal reddening and the observed[O ii]/Hαline ratios are linked.The trend of[O ii]/Hαwith reddening has the smaller scatter.Reddening,therefore,is an im-portant factor in the observed trend of[O ii]/Hαwith M B,but it is not uniquely related to galaxy luminos-ity.2.2.Effect of Excitation and MetallicityThe luminosity dependence of the[O ii]/Hαratio does not disappear completely after correction for reddening.Might the variation in the reddening cor-rected[O ii]/Hαratios result from differences in the excitation state and metallicity of the ISM?Differ-ences in excitation and metallicity affect the relative strengths of the[O ii][O iii]and the hydrogen re-combination lines.Figure3a shows the reddening corrected[O ii]/Hβversus[O iii]λλ4959,5007/Hβflux ratios for the85 galaxy subsample.Here,we used Hβrather than Hα(note that Hα=2.85Hβafter reddening correction) to allow a direct comparison of the data with the theoretical predictions of McCall,Rybski,&Shields (1985)for the line ratios of H ii regions in galaxies as a function of metallicity.Along the track,the metal-licity is high at the lower left(low excitation)and low at the upper right(high excitation).The small systematic deviations(∼0.1dex)from the model are in the same sense that McCall et al.(1985)reported for their comparison of the model and observations. The scatter of0.06dex of the data around the model track is consistent with the errors in the data points. The residuals from the model track are not corre-lated with either absolute B magnitude,reddening E(B−V),galaxy color,or Hαemission line strength. The tight coupling between[O ii]/Hαand metal-licity can be demonstrated with the metallicity sensi-tive ratio log{([O ii]+[O iii]λλ4959,5007)/Hβ},com-monly denoted as R23(Pagel et al.1979;Edmunds& Pagel1984),which we use as a quantitative indica-tor of the oxygen abundance(Pagel1997;Kennicutt et al.2000).Infigure3b we plot the reddening cor-rected[O ii]/Hαratios versus R23.R23is computed using reddening correctedflux ratios.The metallic-ity measurements are degenerate for values of R23= log{([O ii]+[O iii])/Hβ}∼>0.75(metallicities lower than∼0.6times solar when adopting the expansion in R23given by Zaritsky,Kennicutt,&Huchra1994). This is indicated in thefigure by a dotted line.The[O ii]/Hαratio is strongly correlated with metallicity.For R23<0.75(where the metallicity de-termination is non-degenerate)we can approximate the dependence on metallicity with a linear relation: log([O ii]/Hα)cor=(0.82±0.03)R23−(0.48±0.02) The scatter around this relation is only0.023dex, consistent with little or no intrinsic error.1Throughout this paper we will express scatter in terms of the Median Absolute Deviation(MAD),defined as1JANSEN,FRANX,&FABRICANT5Fig.3—(a )Reddening corrected [O ii ]/H βversus [O iii ]λλ4959,5007/H βflux ratios.The theoretical sequence of McCall et al.(1985)is overlayed.The scatter of the data around the model curve is consistent with the errors in the data points.Low excitations are found at the lower left of the model curve,high excitations at the upper right.(b )Reddening corrected [O ii ]/H αratio versus the metallicity sensitive index R 23=log {([O ii ]+[O iii ])/H β}.The metallicity determination is degenerate for R 23∼>0.75(indicated by the dotted line).The [O ii ]/H αratio and the oxygen abundance are strongly correlated.The data points for R 23<0.75follow a well defined sequence with little or no intrinsic scatter.(c )R 23versus total absolute B magnitude.The dotted line indicates the degeneracy limit R 23=0.75.Thus,we identify metallicity as the underlying cause of the observed range in [O ii ]/H α,affecting this ratio both indirectly through the differential extinc-tion of the [O ii ]and H αlines,and directly,as shown above.In figure 3c we plot the metallicity sensitive R 23index versus absolute B magnitude to explicitly show the correlation of metallicity with luminosity.ING [O ii ]AND H αAS TRACERS OF THE SFRIn the following discussion we use the reddening corrected H αflux,H αo ,to parameterize the SFR since this H αflux is directly proportional to the ion-izing flux,F ion .In figure 4a we plot the ratio of the observed [O ii ]flux and the ionizing flux (H αo )versus the absolute B magnitude.A clear trend with luminosity is seen:6[O II ]AS A TRACER OF STARFORMATIONFig.4—(a )Logarithm of the ratio of observed [O ii ]flux to ionizing flux versus total absolute B magnitude.The zeropoint on the ordinate is arbitrary (see text).The plotting symbols are coded according to morphological type as in figure 1.The total range in [O ii ]obs /H αo spans 1.5orders of magnitude.(b )Logarithm of the ratio of observed H αflux to ionizing flux versus M B .Imperfect correction for reddening is a much more serious problem when using [O ii ](see figure 2a )than when using H α.the lowest luminosity galaxies have the largest ratio of [O ii ]to ionizing flux.Near the characteristic absolute B magnitude of the local galaxy luminosity function,M ∗∼−19,the [O ii ]/H αo ratio varies by a factor of ∼10.The total range spans a factor 25.The SFR derived from observed [O ii ]fluxes,in the absence of other information,will be uncertain by a factor of ∼5,if the calibration of Kennicutt (1992)and the median absolute magnitude of his sample is used as a reference (see section 3.1).Using reddening cor-rected instead of observed [O ii ]fluxes (see figure 2b )greatly reduces both the luminosity dependence and the scatter at a given luminosity:from 0.147to 0.035dex/mag and from 0.19dex to 0.08dex,respectively.The total range of the reddening corrected [O ii ]/H αo ratio spans 0.53dex (0.49dex,if we exclude one out-lying data point).As expected,reddening is a more significant source of error if [O ii ]rather than H αflux is used as a SFR tracer.In figure 4b we plot the ratio of the observed H αflux and the ionizing flux versus the absolute B magnitude for comparison.The total range in the ratio of the uncorrected and corrected H αflux spans 0.65dex (a factor of ∼4.5),less than one-fifth that found for [O ii ].But here as well reddening produces a trend with galaxy luminosity of 0.060dex/mag.parison with the LiteratureWe compare our measurements for the NFGS sam-ple with those of Kennicutt (1992a)in order totie them to previous absolute calibrations of [O ii ]and H αas SFR tracers.In figure 5we plot ob-served ([O ii ]+[O iii ]λ5007)/H αflux ratios versus ob-served [O iii ]λ5007/[O ii ]flux ratios for both samples.Whereas [O iii ]λ5007/[O ii ]is an excitation sensitive ratio,([O ii ]+[O iii ]λ5007)/H αis sensitive mainly to the oxygen abundance.The galaxies in both sam-ples follow similar trends.Gallagher et al.(1989)did not publish [O iii ]λ5007measuments for their sample,so we are unable to make a similar comparison with their sample.We did however compare the observed [O ii ]/H βflux ratios versus absolute B magnitude for both the NFGS and the Gallagher et al.(1989)sam-ple and found them to be consistent with one another.Kennicutt (1992a)noted that his SFR calibration for the observed L ([O ii ])emission line luminosity ex-ceeded that of Gallagher et al.(1989)by a factor of 3.Adopting the same IMF and conversion factor from H αto SFR for both samples reduces this difference to a factor of 1.57(Kennicutt 1998b).The remain-ing discrepancy he ascribed to excitation differences between the two samples.The median M B of Kennicutt’s sample is −19.3±1.4mag,that of Gallagher et al.is −16.9±2.0.Tak-ing this magnitude difference at face value,we ex-pect (see §3)a difference in the logarithm of the [O ii ]/H αo ratio of 2.4mag ·0.147dex/mag =0.353dex,i.e.,a factor of 2.25.This factor has the correct sign,i.e.,the SFR inferred from a given [O ii ]/H αo ratio is higher for Kennicutt’s sample than for the sample of Gallagher et al.The predicted differenceJANSEN,FRANX,&FABRICANT7Fig.5—Logarithm of the observed ([O ii ]+[O iii ]λ5007)/H αflux ratio versus the logarithm of the observed [O iii ]λ5007/[O ii ]ratio in the sample of Kennicutt (1992a)(labeled K’92)and in the NFGS sample (including the 118galaxies with EW(H α)<−10˚A ).The abscissa is an excitation sensitive ratio,whereas the ordinate is sensitive mainly to the oxygen abun-dance.The data points in both samples follow similar trends.Those data points in the present sample with errors in excess of 0.10dex are indicated by upper limits.is,however,somewhat larger than that actually ob-served.This might be due to the large scatter in the trends with M B ,or to the fact that Kennicutt could not account for the systematic variations in absorp-tion.4.IMPLICATIONS FOR H βAS A SFR TRACERIn section 2we showed that the observed [O ii ]/H αratios strongly depend on the amount of interstellar reddening.H βwill be seriously affected by redden-ing as well.Here we test H βas a quantitative star formation indicator.In figure 6a we plot the ratio of observed H βflux and the ionizing flux versus total absolute B mag-nitude for the 85galaxies with reliable H βmeasure-ments.The H β/H αo ratio varies systematically with luminosity,although not as strongly as the [O ii ]/H αo ratio.The slope of a linear fit to the data is 0.090dex/mag and the scatter around the fit is 0.132dex.The H β/H αo ratio decreases from 0.37at M B =−14to ∼0.09at M B =−21.In most cases where H βcan be secured,the [O iii ]λλ4959,5007lines will be available as well.Fig-ure 6b shows the ratio of the observed H βflux andthe ionizing flux versus the observed [O iii ]/H βra-tio.It is remarkable that for high values of [O iii ]/H βthe absorption is generally very small.The SFR can therefore be estimated relatively well,with a conver-sion constant very different from that for L ∗galax-ies.The scatter increases drastically for lower values of [O iii ]/H β,and the extinction becomes much more significant.When no direct reddening measurement is available (e.g.,when none of the other Balmer lines can be measured reliably)the ionizing flux can be re-trieved to ±0.12dex using the observed H βand [O iii ]fluxes for log([O iii ]/H β)∼>0.2.At smaller observed [O iii ]/H βratios figure 6b will be useful to estimate the likely range in ionizing flux corresponding to a H βmeasurement.5.IMPROVED SFR ESTIMATION AND EMPIRICALCORRECTIONSIn this section our goal is to derive empirical correc-tions to relate the observed [O ii ]emission line flux to the ionizing flux in those cases where H βis not avail-able.We start with the situation where only [O ii ]fluxes are available.As we found above,the correla-tion between absolute magnitude and [O ii ]/H αo (fig-ure 4a )gives an indication of whether a high or low normalization of the [O ii ]–SFR calibration is likely,and may be used to give a relative weight to a set of several normalizations as published in the literature.For instance,at low luminosities the lower normal-ization of Gallagher et al.(1989)for blue irregular galaxies is likely to be more appropriate.Kennicutt’s (1992a)higher normalization,on the other hand,will be a better choice for luminous galaxies.The scat-ter at a given absolute magnitude is a measure of the errors involved in the choice of calibration constant.The [O ii ]equivalent width,EW([O ii ]),can be used to estimate the likely range in the [O ii ]/H αo ratio.In figure 7a we plot the logarithm of the ratio of the observed [O ii ]flux and the reddening corrected H αflux versus the logarithm of (the nega-tive of)the EW([O ii ]).For EW([O ii ])≤−45˚A [i.e.,log {EW([O ii ])}≥1.65]the scatter in [O ii ]/H αo at a given EW([O ii ])is only 0.064dex and the ion-izing flux (and therefore the SFR)can be deter-mined well.The [O ii ]/H αo ratios for these large EW([O ii ])are high (1.04±0.30),and the star forma-tion would be overestimated by a factor of (1.7±0.5)if the SFR normalization for luminous galaxies were used.EW([O ii ])≤−45˚A are found predominantly in the lower luminosity,lower metallicity galaxies.For smaller EW([O ii ])we find a trend toward lower [O ii ]/H αo ratios,but the scatter in [O ii ]/H αo in-creases to an order of magnitude.We note that the lack of galaxies with small EW([O ii ])and large8[O II ]AS A TRACER OF STARFORMATIONFig.6—(a )Logarithm of the ratio of observed H βflux to the ionizing flux (reddening corrected H αflux)versus absolute B magnitude (including the 85galaxies with reliable H βmeasurements).The plotting symbols are coded according to morphological type as in figure 1.Upper limits are used to indicate data points with errors larger than 0.15dex.A linear least-squares fit to the data points is overlayed.The dotted line indicates the intrinsic Balmer decrement,H α/H β=2.85.As was seen for the [O ii ]/H αo ratio (figure 4a ),reddening creates a dependence on galaxy luminosity.(b )Logarithm of the ratio of the observed H βflux to the ionizing flux versus the logarithm of the observed [O iii ]/H βratio.These data can be used to estimate the ionizing flux and its error when both H βand [O iii ]can be measured reliably,but a direct reddening measurement is not available.For log([O iii ]/H β)∼>0.2little reddening is seen and the ionizing flux can be estimated accurately.[O ii ]/H αo ratios may be due to a selection effect:these galaxies are expected to have small EW(H β)and will drop out of the sample with reliable redden-ing corrections.Therefore,the scatter in [O ii ]/H αo ratio for small EW([O ii ])may be underestimated in figure 7a .Broadband colors help to distinguish galaxies that are particularly dusty.In figures 7b and c we plot the logarithm of the ratio of the observed [O ii ]flux to the reddening corrected H αflux versus the effec-tive (U −B )and (B −R )color,respectively.Our ef-fective colors are the average colors measured within the half-light radius in B .Whereas the range in [O ii ]/H αo for galaxies bluer than (U −B )e ∼−0.3or (B −R )e ∼0.95is only ∼0.5dex (a scatter of ∼0.12dex),redder galaxies occupy nearly the full range of observed [O ii ]/H αo .Again,the galaxies dominated by star formation have the highest [O ii ]/H αo ratios.The trends shown here are purely empirical,and the correlations do not have direct physical causes.It remains to be seen if they hold at higher redshifts.6.IMPLICATIONS FOR HIGHER REDSHIFTSIntermediate and high redshift spectroscopic studies like the Hawaii Deep Survey (Cowie et al.1994;Songaila et al.1994;Cowie et al.1996)and the Canada-France Redshift Survey (CFRS;Lilly et al.1995;Hammer et al.1997)have shown that the fraction of relatively bright galaxies with EW([O ii ])<−15˚A increases strongly with redshift.Hammer et al.(1997)showed that converting [O ii ]into a SFR using Kennicutt’s (1992)calibration leads to a production of long-lived stars in excess of the number observed at the present ing the Gallagher et al.(1989)calibration for blue galaxies instead implies that 75%of the present-day mass in stars have been produced since z ∼1.The lumi-nosities sampled in the CFRS survey are comparable to those in the present sample.Hammer et al.(1997)speculate that excitation and/or dust play a role,and our results confirm this.Cowie et al.(1997)found remarkably little extinc-tion in the bulk of the blue star forming galaxies at redshifts z >0.8.The results by Pettini et al.(1998)for a small sample of z ∼3Lyman break galaxies are consistent with this general picture,as their UV selected galaxies generally show low absorption com-pared to our L ∗galaxies.The one possible excep-tion,DSF 2237+116C2,is the reddest,most massive galaxy in their sample.These results indicate that the correlation of reddening and excitation with lu-minosity may change with look-back time,but the colors and equivalent widths might well remain effec-tive indicators of reddening.JANSEN,FRANX,&FABRICANT9Fig.7—(a )Logarithm of the ratio of the observed [O ii ]flux to the ionizing flux versus the logarithm of (the negative of)the [O ii ]equivalent width.Plotting symbols are coded according to morphological type as in figure 1.Upper limits are used to indicate data points with errors larger than 0.15dex.The upper left region may be depleted due to selection effects.(b )Logarithm of the ratio of the observed [O ii ]flux to the ionizing flux versus effective rest-frame (U −B )color.(c )Same as (b )but using effective rest-frame (B −R )color.The uncertainties in the SFR derived from [O ii ]are of the order of a factor of 3if no other information is available.7.SUMMARYWe have used spectrophotometry for 85emission line galaxies from the Nearby Field Galaxy Survey sample to investigate the dependence of the [O ii ]/H αratio on galaxy luminosity.Reddening and excitation differences are the main cause of the anti-correlation between [O ii ]/H αand galaxy luminosity.Both are strongly correlated with absolute magnitude and are likely caused by systematic variation in metallicity as a function of galaxy luminosity.Excitation models match the dust corrected line ratios within the accu-racy of our data.The total variation in the ratio of the observed [O ii ]flux to the reddening corrected H αflux is a factor 25.The observed difference between the [O ii ]–SFR calibrations of Gallagher et al.(1989)and Kenni-cutt (1992a)is in the sense expected from the differ-ence in galaxy luminosity between the two samples.We confirm the conjecture of Hammer et al.(1997)that systematic variations in reddening by dust play an important role when interpreting emission line strengths in terms of SFRs.When corrections for metallicity and dust are not possible,the use of [O ii ]fluxes to measure star forma-tion rates may result in an overestimate of a factor of 3if local calibrations for luminous galaxies are used.We show that H βis a significantly better tracer of star formation than [O ii ],and we discuss some em-pirical trends which may be useful in the high redshift regime.ACKNOWLEDGEMENTSThis work was supported by grants from the Uni-versity of Groningen,the Leiden Kerkhoven-Bosscha Fund,the Netherlands Organisation for Scientific Re-search (NWO),and by the Smithsonian Institution.We thank the CfA TAC for generously allocating time for this project over three years.R. 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第９卷㊀第２期２０２４年３月气体物理ＰＨＹＳＩＣＳＯＦＧＡＳＥＳＶｏｌ.９㊀Ｎｏ.２Ｍａｒ.２０２４㊀㊀ＤＯＩ:１０.１９５２７/ｊ.ｃｎｋｉ.２０９６￣１６４２.１０９８Ｍａｃｈ数和壁面温度对ＨｙＴＲＶ边界层转捩的影响章录兴ꎬ㊀王光学ꎬ㊀杜㊀磊ꎬ㊀余发源ꎬ㊀张怀宝(中山大学航空航天学院ꎬ广东深圳５１８１０７)ＥｆｆｅｃｔｓｏｆＭａｃｈＮｕｍｂｅｒａｎｄＷａｌｌＴｅｍｐｅｒａｔｕｒｅｏｎＨｙＴＲＶＢｏｕｎｄａｒｙＬａｙｅｒＴｒａｎｓｉｔｉｏｎＺＨＡＮＧＬｕｘｉｎｇꎬ㊀ＷＡＮＧＧｕａｎｇｘｕｅꎬ㊀ＤＵＬｅｉꎬ㊀ＹＵＦａｙｕａｎꎬ㊀ＺＨＡＮＧＨｕａｉｂａｏ(ＳｃｈｏｏｌｏｆＡｅｒｏｎａｕｔｉｃｓａｎｄＡｓｔｒｏｎａｕｔｉｃｓꎬＳｕｎＹａｔ￣ｓｅｎＵｎｉｖｅｒｓｉｔｙꎬＳｈｅｎｚｈｅｎ５１８１０７ꎬＣｈｉｎａ)摘㊀要:典型的高超声速飞行器流场存在着复杂的转捩现象ꎬ其对飞行器的性能有着显著的影响ꎮ针对ＨｙＴＲＶ这款接近真实高超声速飞行器的升力体模型ꎬ采用数值模拟方法ꎬ研究Ｍａｃｈ数和壁面温度对ＨｙＴＲＶ转捩的影响规律ꎮ采用课题组自研软件开展数值计算ꎬＭａｃｈ数的范围为３~８ꎬ壁面温度的范围为１５０~９００Ｋꎮ首先对γ￣Ｒｅ~θｔ转捩模型和ＳＳＴ湍流模型进行了高超声速修正:将压力梯度系数修正㊁高速横流修正引入到γ￣Ｒｅ~θｔ转捩模型ꎬ并对ＳＳＴ湍流模型闭合系数β∗和β进行可压缩修正ꎻ然后开展了网格无关性验证ꎬ通过与实验结果对比ꎬ确认了修正后的数值方法和软件平台ꎻ最终开展Ｍａｃｈ数和壁面温度对ＨｙＴＲＶ边界层转捩规律的影响研究ꎮ计算结果表明ꎬ转捩区域主要集中在上表面两侧㊁下表面中心线两侧ꎻ增大来流Ｍａｃｈ数ꎬ上下表面转捩起始位置均大幅后移ꎬ湍流区大幅缩小ꎬ但仍会存在ꎬ同时上表面层流区摩阻系数不断增大ꎬ下表面湍流区摩阻系数不断减小ꎻ升高壁面温度ꎬ上下表面转捩起始位置先前移ꎬ然后快速后移ꎬ最终湍流区先后几乎消失ꎮ关键词:转捩ꎻＨｙＴＲＶꎻ摩阻ꎻＭａｃｈ数ꎻ壁面温度㊀㊀㊀收稿日期:２０２３￣１２￣１３ꎻ修回日期:２０２４￣０１￣０２基金项目:国家重大项目(ＧＪＸＭ９２５７９)ꎻ广东省自然科学基金－面上项目(２０２３Ａ１５１５０１００３６)ꎻ中山大学中央高校基本科研业务费专项资金(２２ｑｎｔｄ０７０５)第一作者简介:章录兴(１９９８ )㊀男ꎬ硕士ꎬ主要研究方向为高超声速空气动力学ꎮＥ￣ｍａｉｌ:184****8082＠１６３.ｃｏｍ通信作者简介:张怀宝(１９８５ )㊀男ꎬ副教授ꎬ主要研究方向为空气动力学ꎮＥ￣ｍａｉｌ:ｚｈａｎｇｈｂ２８＠ｍａｉｌ.ｓｙｓｕ.ｅｄｕ.ｃｎ中图分类号:Ｖ２１１ꎻＶ４１１㊀㊀文献标志码:ＡＡｂｓｔｒａｃｔ:Ｔｈｅｒｅｉｓａｃｏｍｐｌｅｘｔｒａｎｓｉｔｉｏｎｐｈｅｎｏｍｅｎｏｎｉｎｔｈｅｆｌｏｗｆｉｅｌｄｏｆａｔｙｐｉｃａｌｈｙｐｅｒｓｏｎｉｃｖｅｈｉｃｌｅꎬｗｈｉｃｈｈａｓａｓｉｇｎｉｆｉ￣ｃａｎｔｉｍｐａｃｔｏｎｔｈｅｐｅｒｆｏｒｍａｎｃｅｏｆｔｈｅｖｅｈｉｃｌｅ.ＴｈｅｅｆｆｅｃｔｓｏｆＭａｃｈｎｕｍｂｅｒａｎｄｗａｌｌｔｅｍｐｅｒａｔｕｒｅｏｎｔｈｅｔｒａｎｓｉｔｉｏｎｏｆＨｙＴＲＶｗｅｒｅｓｔｕｄｉｅｄｂｙｎｕｍｅｒｉｃａｌｓｉｍｕｌａｔｉｏｎｍｅｔｈｏｄｓ.Ｔｈｅｓｅｌｆ￣ｄｅｖｅｌｏｐｅｄｓｏｆｔｗａｒｅｏｆｔｈｅｒｅｓｅａｒｃｈｇｒｏｕｐｗａｓｕｓｅｄｔｏｃａｒｒｙｏｕｔｎｕ￣ｍｅｒｉｃａｌｃａｌｃｕｌａｔｉｏｎｓ.ＴｈｅｒａｎｇｅｏｆＭａｃｈｎｕｍｂｅｒｗａｓ３~８ꎬａｎｄｔｈｅｒａｎｇｅｏｆｗａｌｌｔｅｍｐｅｒａｔｕｒｅｗａｓ１５０~９００Ｋ.Ｆｉｒｓｔｌｙꎬｔｈｅｈｙｐｅｒｓｏｎｉｃｃｏｒｒｅｃｔｉｏｎｓｏｆｔｈｅγ￣Ｒｅ~θｔｔｒａｎｓｉｔｉｏｎｍｏｄｅｌａｎｄｔｈｅＳＳＴｔｕｒｂｕｌｅｎｃｅｍｏｄｅｌｗｅｒｅｃａｒｒｉｅｄｏｕｔ.Ｔｈｅｐｒｅｓｓｕｒｅｇｒａｄｉｅｎｔｃｏｅｆｆｉｃｉｅｎｔｃｏｒｒｅｃｔｉｏｎａｎｄｔｈｅｈｉｇｈ￣ｓｐｅｅｄｃｒｏｓｓ￣ｆｌｏｗｃｏｒｒｅｃｔｉｏｎｗｅｒｅｉｎｔｒｏｄｕｃｅｄｉｎｔｏｔｈｅγ￣Ｒｅ~θｔｔｒａｎｓｉｔｉｏｎｍｏｄｅｌꎬａｎｄｔｈｅｃｏｍ￣ｐｒｅｓｓｉｂｉｌｉｔｙｃｏｒｒｅｃｔｉｏｎｓｏｆｔｈｅｃｌｏｓｕｒｅｃｏｅｆｆｉｃｉｅｎｔｓβ∗ａｎｄβｏｆｔｈｅＳＳＴｔｕｒｂｕｌｅｎｃｅｍｏｄｅｌｗｅｒｅｃａｒｒｉｅｄｏｕｔ.Ｔｈｅｎꎬｔｈｅｇｒｉｄｉｎ￣ｄｅｐｅｎｄｅｎｃｅｖｅｒｉｆｉｃａｔｉｏｎｗａｓｃａｒｒｉｅｄｏｕｔꎬａｎｄｔｈｅｍｏｄｉｆｉｅｄｎｕｍｅｒｉｃａｌｍｅｔｈｏｄａｎｄｓｏｆｔｗａｒｅｐｌａｔｆｏｒｍｗｅｒｅｃｏｎｆｉｒｍｅｄｂｙｃｏｍ￣ｐａｒｉｎｇｗｉｔｈｅｘｐｅｒｉｍｅｎｔａｌｒｅｓｕｌｔｓ.ＦｉｎａｌｌｙꎬｔｈｅｅｆｆｅｃｔｓｏｆＭａｃｈｎｕｍｂｅｒａｎｄｗａｌｌｔｅｍｐｅｒａｔｕｒｅｏｎｔｈｅｔｒａｎｓｉｔｉｏｎｌａｗｏｆｔｈｅＨｙＴＲＶｂｏｕｎｄａｒｙｌａｙｅｒｗｅｒｅｓｔｕｄｉｅｄ.Ｔｈｅｒｅｓｕｌｔｓｓｈｏｗｔｈａｔｔｈｅｔｒａｎｓｉｔｉｏｎａｒｅａｉｓｍａｉｎｌｙｃｏｎｃｅｎｔｒａｔｅｄｏｎｂｏｔｈｓｉｄｅｓｏｆｔｈｅｕｐｐｅｒｓｕｒｆａｃｅａｎｄｔｈｅｃｅｎｔｅｒｌｉｎｅｏｆｔｈｅｌｏｗｅｒｓｕｒｆａｃｅ.ＷｉｔｈｔｈｅｉｎｃｒｅａｓｅｏｆｔｈｅｉｎｃｏｍｉｎｇＭａｃｈｎｕｍｂｅｒꎬｔｈｅｓｔａｒｔｉｎｇｐｏｓｉｔｉｏｎｏｆｔｒａｎｓｉｔｉｏｎｏｎｔｈｅｕｐｐｅｒａｎｄｌｏｗｅｒｓｕｒｆａｃｅｓｉｓｇｒｅａｔｌｙｂａｃｋｗａｒｄꎬａｎｄｔｈｅｔｕｒｂｕｌｅｎｔｚｏｎｅｉｓｇｒｅａｔｌｙｒｅｄｕｃｅｄꎬｂｕｔｉｔｓｔｉｌｌｅｘ￣ｉｓｔｓ.Ａｔｔｈｅｓａｍｅｔｉｍｅꎬｔｈｅｆｒｉｃｔｉｏｎｃｏｅｆｆｉｃｉｅｎｔｏｆｔｈｅｌａｍｉｎａｒｆｌｏｗｚｏｎｅｏｎｔｈｅｕｐｐｅｒｓｕｒｆａｃｅｉｎｃｒｅａｓｅｓｃｏｎｔｉｎｕｏｕｓｌｙꎬａｎｄｔｈｅｆｒｉｃｔｉｏｎｃｏｅｆｆｉｃｉｅｎｔｏｆｔｈｅｔｕｒｂｕｌｅｎｔｚｏｎｅｏｎｔｈｅｌｏｗｅｒｓｕｒｆａｃｅｄｅｃｒｅａｓｅｓ.Ａｓｔｈｅｗａｌｌｔｅｍｐｅｒａｔｕｒｅｉｎｃｒｅａｓｅｓꎬｔｈｅｓｔａｒｔｉｎｇｐｏｓｉ￣ｔｉｏｎｏｆｔｒａｎｓｉｔｉｏｎｏｎｔｈｅｕｐｐｅｒａｎｄｌｏｗｅｒｓｕｒｆａｃｅｓｓｈｉｆｔｓｆｏｒｗａｒｄꎬｔｈｅｎｒａｐｉｄｌｙｓｈｉｆｔｓｂａｃｋｗａｒｄꎬａｎｄｆｉｎａｌｌｙｔｈｅｔｕｒｂｕｌｅｎｔｚｏｎｅａｌｍｏｓｔｄｉｓａｐｐｅａｒｓ.气体物理２０２４年㊀第９卷Ｋｅｙｗｏｒｄｓ:ｔｒａｎｓｉｔｉｏｎꎻＨｙＴＲＶꎻｆｒｉｃｔｉｏｎꎻＭａｃｈｎｕｍｂｅｒꎻｗａｌｌｔｅｍｐｅｒａｔｕｒｅ引㊀言高超声速飞行器具有突防能力强㊁打击范围广㊁响应迅速等显著优势ꎬ正逐渐成为各国空天竞争的热点[１]ꎮ高超声速飞行器边界层转捩是该类飞行器气动设计中的重要问题[２]ꎮ在边界层转捩过程中ꎬ流态由层流转变为湍流ꎬ飞行器的表面摩阻急剧增大到层流时的３~５倍ꎬ严重影响飞行器的气动性能与热防护系统ꎬ转捩还会导致飞行器壁面烧蚀㊁颤振加剧㊁飞行姿态控制难度大等一系列问题ꎬ对飞行器的飞行安全构成严重的威胁[３￣５]ꎬ开展高超声速飞行器边界层转捩研究具有十分重要的意义ꎮ影响边界层转捩的因素很多ꎬ例如ꎬＭａｃｈ数㊁Ｒｅｙｎｏｌｄｓ数㊁湍流强度㊁表面传导热等ꎮ在高超声速流动条件下ꎬ强激波㊁强逆压梯度㊁熵层等高超声速现象及其相互作用ꎬ会使得转捩流动的预测和研究难度进一步增大[６]ꎮ目前高超声速飞行器转捩数值模拟方法主要有直接数值模拟(ＤＮＳ)㊁大涡模拟(ＬＥＳ)和基于Ｒｅｙｎｏｌｄｓ平均Ｎａｖｉｅｒ￣Ｓｔｏｋｅｓ(ＲＡＮＳ)的转捩模型方法ꎬ由于前两种计算量巨大ꎬ难以推广到工程应用ꎬ基于Ｒｅｙｎｏｌｄｓ平均Ｎａｖｉｅｒ￣Ｓｔｏｋｅｓ的转捩模型在工程实践中应用最为广泛ꎬ其中γ￣Ｒｅ~θｔ转捩模型基于局部变量ꎬ与现代ＣＦＤ方法良好兼容ꎬ目前已经有多项研究尝试从一般性的流动问题拓展到高超声速流动转捩模拟[６￣９]ꎮ目前高超声速流动转捩的研究对象主要是结构相对简单的构型ꎮＭｃＤａｎｉｅｌ等[１０]研究了扩口直锥在高超声速流动条件下的转捩现象ꎮＰａｐｐ等[１１]研究了圆锥在高超声速流动条件下的转捩特性ꎮ美国和澳大利亚组织联合实施的ＨＩＦｉＲＥ计划[１２]ꎬ研究了圆锥形状的ＨＩＦｉＲＥ１和椭圆锥形的ＨＩＦｉＲＥ５的转捩问题ꎮ杨云军等[１３]采用数值模拟方法ꎬ分析了椭圆锥的转捩影响机制ꎬ并研究了Ｒｅｙｎｏｌｄｓ数对转捩特性的影响规律ꎮ另外ꎬ袁先旭等[１４]于２０１５年成功实施了圆锥体ＭＦ￣１航天模型飞行试验ꎮ以上对高超声速流动的转捩研究ꎬ都取得了比较理想的结果ꎬ然而所采用的模型都是圆锥㊁椭圆锥等简单几何外形ꎬ这与真实高超声速飞行器有较大差异ꎬ较难反映真实的转捩特性ꎮ为了有效促进对真实高超声速飞行器的转捩问题研究ꎬ中国空气动力研究与发展中心提出并设计了一款接近真实飞行器的升力体模型ꎬ即高超声速转捩研究飞行器(ｈｙｐｅｒｓｏｎｉｃｔｒａｎｓｉｔｉｏｎｒｅｓｅａｒｃｈｖｅｈｉｃｌｅꎬＨｙＴＲＶ)[１５]ꎬ模型详细的参数见参考文献[１６]ꎮＨｙＴＲＶ外形如图１所示ꎬ其整体外形较为复杂ꎬ不同区域发生转捩的情况也不尽相同ꎮ对ＨｙＴＲＶ的转捩问题研究能够显著提高对真实高超声速飞行器转捩特性的认识水平ꎮＬｉｕ等[１７]采用理论分析㊁数值模拟和风洞实验３种方法对ＨｙＴＲＶ的转捩特性进行了研究ꎻ陈坚强等[１５]分析了ＨｙＴＲＶ的边界层失稳特征ꎻＣｈｅｎ等[１８]对ＨｙＴＲＶ进行了多维线性稳定性分析ꎻＱｉ等[１９]在来流Ｍａｃｈ数６㊁攻角０ʎ的条件下对ＨｙＴＲＶ进行了直接数值模拟ꎻ万兵兵等[２０]结合风洞实验与飞行试验ꎬ利用ｅＮ方法预测了ＨｙＴＲＶ升力体横流区的转捩阵面形状ꎮ目前ꎬ相关研究主要集中在ＨｙＴＲＶ的稳定性特征及转捩预测两个方面ꎬ而对若干关键参数ꎬ特别是Ｍａｃｈ数和壁面温度对转捩的影响研究还比较少ꎮ(ａ)Ｆｒｏｎｔｖｉｅｗ(ｂ)Ｓｉｄｅｖｉｅｗ㊀㊀㊀图１㊀ＨｙＴＲＶ外形Ｆｉｇ.１㊀ＳｈａｐｅｏｆＨｙＴＲＶ基于此ꎬ本文采用数值模拟方法ꎬ应用课题组自研软件开展Ｍａｃｈ数和壁面温度对ＨｙＴＲＶ转捩流动的影响规律研究ꎮ１㊀数值方法１.１㊀控制方程和数值方法控制方程为三维可压缩ＲＡＮＳ方程ꎬ采用结构网格技术和有限体积方法ꎬ变量插值方法采用２阶ＭＵＳＣＬ格式ꎬ通量计算采用低耗散的通量向量差分Ｒｏｅ格式ꎬ黏性项离散采用中心格式ꎬ时间推进方法采用ＬＵ￣ＳＧＳ格式ꎮ壁面采用等温㊁无滑移壁面条件ꎬ入口采用Ｒｉｅｍａｎｎ远场边界条件ꎬ出口采用零梯度外推边界条件ꎮ１.２㊀γ￣Ｒｅ~θｔ转捩模型γ￣Ｒｅ~θｔ转捩模型是Ｍｅｎｔｅｒ等[２１ꎬ２２]于２００４年提０１第２期章录兴ꎬ等:Ｍａｃｈ数和壁面温度对ＨｙＴＲＶ边界层转捩的影响出的一种基于拟合公式的间歇因子转捩模型ꎬ在２００９年公布了完整的拟合公式及相关参数[２３]ꎮ许多学者也开发了相应的程序ꎬ并进行了大量的算例验证[２４￣２８]ꎬ证明了该模型具有较好的转捩预测能力ꎬ预测精度较高ꎻ通过合适的标定ꎬγ￣Ｒｅ~θｔ转捩模型可以适用于多种情况下的转捩模拟ꎮ该模型构建了关于间歇因子γ的输运方程和关于转捩动量厚度Ｒｅｙｎｏｌｄｓ数Ｒｅ~θｔ的输运方程ꎮ具体来说ꎬγ表示该位置是湍流流动的概率ꎬ取值范围为０<γ<１ꎮ关于γ的控制方程为Ə(ργ)Əｔ＋Ə(ρｕｊγ)Əｘｊ＝Ｐγ－Ｅγ＋ƏƏｘｊμ＋μｔσｆæèçöø÷ƏγƏｘｊéëêêùûúú其中ꎬＰγ为生成项ꎬＥγ为破坏项ꎮ关于Ｒｅ~θｔ的输运方程为Ə(ρＲｅ~θｔ)Əｔ＋Ə(ρｕｊＲｅ~θｔ)Əｘｊ＝Ｐθｔ＋ƏƏｘｊσθｔ(μ＋μｔ)ƏＲｅ~θｔƏｘｊéëêêùûúú其中ꎬＰθｔ为源项ꎬ其作用是使边界层外部的Ｒｅ~θｔ等于Ｒｅθｔꎬ定义式为Ｐθｔ＝ｃθｔρｔ(Ｒｅθｔ－Ｒｅ~θｔ)(１.０－Ｆθｔ)Ｒｅθｔ采用以下经验公式Ｒｅθｔ＝１１７３.５１－５８９ ４２８Ｔｕ＋０.２１９６Ｔｕ２æèçöø÷Ｆ(λθ)ꎬＴｕɤ０.３Ｒｅθｔ＝３３１.５０(Ｔｕ－０.５６５８)－０.６７１Ｆ(λθ)ꎬＴｕ>０.３ìîíïïïïＦ(λθ)＝１＋(１２.９８６λθ＋１２３.６６λ２θ＋４０５.６８９λ３θ)ｅ－(Ｔｕ１.５)１.５ꎬ㊀λθɤ０Ｆ(λθ)＝１＋０.２７５(１－ｅ－３５.０λθ)ｅ－(Ｔｕ０.５)ꎬλθ>０ìîíïïïï在实际计算中ꎬ通过γ￣Ｒｅ~θｔ转捩模型获得间歇因子ꎬ再通过间歇因子来控制ＳＳＴｋ￣ω湍流模型中湍动能的生成ꎮγ￣Ｒｅ~θｔ转捩模型与ＳＳＴｋ￣ω湍流模型耦合为Ə(ρｋ)Əｔ＋Ə(ρｕｊｋ)Əｘｊ＝γｅｆｆτｉｊƏｕｉƏｘｊ－ｍｉｎ(ｍａｘ(γｅｆｆꎬ０.１)ꎬ１.０)ρβ∗ｋω＋ƏƏｘｊμ＋μｔσｋæèçöø÷ƏｋƏｘｊéëêêùûúúƏ(ρω)Əｔ＋Ə(ρｕｊω)Əｘｊ＝γｖｔτｉｊƏｕｉƏｘｊ－βρω２＋ƏƏｘｊ(μ＋σωμｔ)ƏωƏｘｊéëêêùûúú＋２ρ(１－Ｆ１)σω２１ωƏｋƏｘｊƏωƏｘｊ模型中具体参数定义见文献[２３]ꎮ１.３㊀高超声速修正原始ＳＳＴ湍流模型及γ￣Ｒｅ~θｔ转捩模型都是基于不可压缩流动发展的ꎬ为了更好地预测高超声速流动转捩ꎬ本节引入了３种重要的高超声速修正方法ꎮ１.３.１㊀压力梯度修正压力梯度对边界层转捩的影响较大ꎬ在高Ｍａｃｈ数情况下ꎬ边界层厚度较大ꎬ进而影响压力梯度的大小ꎬ因此在模拟高超声速流动时应该考虑Ｍａｃｈ数对压力梯度的影响ꎮ本文采用张毅峰等[２９]提出的压力梯度修正方法ꎬ具体修正形式如下λᶄθ＝λθ１＋γᶄ－１２Ｍａｅæèçöø÷其中ꎬＭａｅ为边界层外缘Ｍａｃｈ数ꎬγᶄ为比热比ꎮ１.３.２㊀高速横流修正在原始γ￣Ｒｅ~θｔ转捩模型中ꎬ没有考虑横流不稳定性对转捩的影响ꎬ对于横流模态主导的转捩ꎬ原始转捩模型计算的结果并不理想ꎮＬａｎｇｔｒｙ等[３０]在２０１５年对γ￣Ｒｅ~θｔ转捩模型进行了低速横流修正ꎬ向星皓等[９]在Ｌａｎｇｔｒｙ低速横流修正的基础上ꎬ对高超声速椭圆锥转捩ＤＮＳ数据进行了拓展ꎬ提出了高速横流转捩判据ꎬ本文直接采用向星皓提出的高速横流转捩方法ꎮＬａｎｇｔｒｙ将横流强度引入转捩发生动量厚度Ｒｅｙｎｏｌｄｓ数输运方程中Ə(ρＲｅ~θｔ)Əｔ＋Ə(ρｕｊＲｅ~θｔ)Əｘｊ＝Ｐθｔ＋ＤＳＣＦ＋ƏƏｘｊσθｔ(μ＋μｔ)ƏＲｅ~θｔƏｘｊéëêêùûúú式中ꎬＤＳＣＦ为横流源项ꎬＬａｎｇｔｒｙ低速横流修正为ＤＳＣＦ＝ｃθｔρｔｃｃｒｏｓｓｆｌｏｗｍｉｎ(ＲｅＳＣＦ－Ｒｅ~θｔꎬ０.０)Ｆθｔ２其中ꎬＲｅＳＣＦ为低速横流判据ＲｅＳＣＦ＝θｔρＵｌｏｃａｌ０.８２æèçöø÷μ＝－３５.０８８ｌｎｈθｔæèçöø÷＋３１９.５１＋ｆ(＋ΔＨｃｒｏｓｓｆｌｏｗ)－ｆ(－ΔＨｃｒｏｓｓｆｌｏｗ)其中ꎬｈ为壁面粗糙度高度ꎬθｔ为动量厚度ꎬ１１气体物理２０２４年㊀第９卷ΔＨｃｒｏｓｓｆｌｏｗ是横流强度抬升项ꎮ向星皓提出的高速横流转捩判据ꎬ其中高速横流源项ＤＳＣＦ￣Ｈ为ＤＳＣＦ￣Ｈ＝ｃＣＦρｍｉｎ(ＲｅＳＣＦ￣Ｈ－Ｒｅ~θｔꎬ０)ＦθｔＲｅＳＣＦ￣Ｈ＝ＣＣＦ￣１ｌｎｈｌμ＋ＣＣＦ￣２＋(Ｈｃｒｏｓｓｆｌｏｗ)其中ꎬＣＣＦ￣１＝－９.６１８ꎬＣＣＦ￣２＝１２８.３３ꎻｌμ为粗糙度参考高度ꎬｌμ＝１μｍꎻｆ(Ｈｃｒｏｓｓｆｌｏｗ)为抬升函数ｆ(Ｈｃｒｏｓｓｆｌｏｗ)＝６００００.１０６６－ΔＨｃｒｏｓｓｆｌｏｗ＋５００００(０.１０６６－ΔＨｃｒｏｓｓｆｌｏｗ)２其中ꎬΔＨｃｒｏｓｓｆｌｏｗ与Ｌａｎｇｔｒｙ低速横流修正中保持一致ꎮ１.３.３㊀ＳＳＴ可压缩修正高超声速流动具有强可压缩性ꎬ所以在进行高超声速计算时ꎬ应该对湍流模型进行可压缩修正ꎮＳａｒｋａｒ[３１]提出了膨胀耗散修正ꎬ对ＳＳＴ湍流模型中的闭合系数β∗ꎬβ进行了可压缩修正ꎬＷｉｌｃｏｘ[３２]在Ｓａｒｋａｒ修正的基础上考虑了可压缩生成项产生时的延迟效应ꎬ使得可压缩修正在湍流Ｍａｃｈ数较小的近壁面关闭ꎬ在湍流Ｍａｃｈ数较大的自由剪切层打开ꎬ本文采用Ｗｉｌｃｏｘ提出的可压缩性修正β∗＝β∗０[１＋ξ∗Ｆ(Ｍａｔ)]β＝β０－β∗０ξ∗Ｆ(Ｍａｔ)其中ꎬβ０ꎬβ∗均为原始模型中的系数ꎬξ∗＝１.５ꎮＦ(Ｍａｔ)＝[Ｍａｔ－Ｍａｔ０]Ｈ(Ｍａｔ－Ｍａｔ０)Ｍａｔ０＝１/４ꎬＨ(ｘ)＝０ꎬｘɤ０１ꎬｘ>０{其中ꎬＭａｔ＝２ｋ/ａ为湍流Ｍａｃｈ数ꎬａ为当地声速ꎮ２㊀网格无关性验证及数值方法确认２.１㊀网格无关性验证计算采用３套网格ꎬ考虑到ＨｙＴＲＶ的几何对称性ꎬ生成３套半模网格ꎬ第１层网格高度为１ˑ１０－６ｍꎬ确保ｙ＋<１ꎬ流向ˑ法向ˑ周向的网格数分别为:网格１是３０１ˑ２０１ˑ２０１ꎬ网格２是３０１ˑ３０１ˑ２０１ꎬ网格３是４０１ˑ３８１ˑ２８１ꎮ全模下表面如图２所示ꎬ选取ｙ/Ｌ＝０中心线和ｘ/Ｌ＝０.５处ꎬ对比３套网格的表面摩阻系数ꎬ计算结果如图３所示ꎮ采用网格１时ꎬ表面摩阻系数分布与另外两个结果存在明显差异ꎻ而采用网格２和网格３时ꎬ表面摩阻系数曲线基本重合ꎬ表明在流向㊁法向和周向均满足网格无关性ꎬ后续数值计算采用网格２ꎮ图２㊀截取位置示意图Ｆｉｇ.２㊀Ｓｃｈｅｍａｔｉｃｄｉａｇｒａｍｏｆｔｈｅｉｎｔｅｒｃｅｐｔｉｏｎｌｏｃａｔｉｏｎ(ａ)Ｓｕｒｆａｃｅｆｒｉｃｔｉｏｎａｔｙ/Ｌ＝０(ｂ)Ｓｕｒｆａｃｅｆｒｉｃｔｉｏｎａｔｘ/Ｌ＝０.５图３㊀采用３套网格计算得到的摩阻对比Ｆｉｇ.３㊀Ｃｏｍｐａｒｉｓｏｎｏｆｔｈｅｆｒｉｃｔｉｏｎｄｒａｇｃａｌｃｕｌａｔｅｄｕｓｉｎｇｔｈｒｅｅｓｅｔｓｏｆｇｒｉｄｓ２.２㊀数值方法和自研软件的确认采用修正后的转捩模型对ＨｙＴＲＶ开展计算ꎬ计算工况为Ｍａ＝６ꎬ来流温度Ｔɕ＝９７Ｋꎬ单位２１第２期章录兴ꎬ等:Ｍａｃｈ数和壁面温度对ＨｙＴＲＶ边界层转捩的影响Ｒｅｙｎｏｌｄｓ数为Ｒｅ＝１.１ˑ１０７/ｍꎬ攻角α＝０ʎꎬ来流湍流度ＦＳＴＩ＝０.８％ꎬ壁面温度Ｔ＝３００Ｋꎮ为方便对比分析ꎬ计算结果与参考结果均采用上下对称形式布置ꎬ例如ꎬ图４是模型下表面计算结果与实验结果对比:对于下表面两侧转捩的起始位置ꎬ高超声速修正前的转捩位置在ｘ＝０.６８ｍ附近ꎬ高超声速修正后的计算结果与实验结果吻合良好ꎬ均在ｘ＝０.６０ｍ附近ꎬ并且湍流边界层区域形状基本一致ꎬ说明修正后的转捩模型能够较好地预测ＨｙＴＲＶ转捩的位置ꎮ(ａ)Ｃａｌｃｕｌａｔｉｏｎｏｆｔｈｅｆｒｉｃｔｉｏｎｄｉｓｔｒｉｂｕｔｉｏｎ(ｂｅｆｏｒｅｈｙｐｅｒｓｏｎｉｃｃｏｒｒｅｃｔｉｏｎ)(ｂ)Ｃａｌｃｕｌａｔｉｏｎｏｆｔｈｅｆｒｉｃｔｉｏｎｄｉｓｔｒｉｂｕｔｉｏｎ(ａｆｔｅｒｈｙｐｅｒｓｏｎｉｃｃｏｒｒｅｃｔｉｏｎ)(ｃ)Ｅｘｐｅｒｉｍｅｎｔａｌｒｅｓｕｌｔｓｏｆｔｈｅｈｅａｔｆｌｕｘｄｉｓｔｒｉｂｕｔｉｏｎ[１７]图４㊀下表面计算结果和实验结果对比Ｆｉｇ.４㊀Ｃｏｍｐａｒｉｓｏｎｏｆｔｈｅｃａｌｃｕｌａｔｅｄａｎｄｅｘｐｅｒｉｍｅｎｔａｌｒｅｓｕｌｔｓｏｎｔｈｅｌｏｗｅｒｓｕｒｆａｃｅ３㊀ＨｙＴＲＶ转捩的基本流动特性计算工况采用Ｍａ＝６ꎬ攻角α＝０ʎꎬ来流湍流度ＦＳＴＩ＝０.６％ꎬ分析ＨｙＴＲＶ转捩的基本流动特性ꎮ从图５可以看出ꎬ模型两侧和顶端均出现高压区ꎬ高压区之间为低压区ꎬ横截面上存在周向压力梯度ꎬ流动从高压区向低压区汇集ꎬ从而在下表面中心线附近和上表面两侧腰部区域均形成流向涡结构(见图６)ꎬ沿流动方向ꎬ高压区域逐渐扩大ꎬ流向涡结构的影响范围也越大ꎮ在流向涡结构的边缘位置ꎬ壁面附近的低速流体被抬升到外壁面区域ꎬ外壁面区域的高速流体又被带入到近壁面区域ꎬ进而导致流向涡结构边缘处壁面的摩阻显著增加ꎬ最终诱发转捩ꎬ这些流动特征与文献[１５]的结果一致ꎮ图７显示了上下表面摩阻的分布情况ꎬ其中上表面两侧区域在ｘ/Ｌ＝０.８０附近ꎬ摩阻显著增加ꎬ出现明显的转捩现象ꎬ转捩区域分布在两侧边缘位置ꎻ而下表面两侧区域在ｘ/Ｌ＝０.７５附近ꎬ也出现明显的转捩ꎬ转捩区域相对集中在中心线两侧ꎮ图５㊀不同截面位置处的压力云图Ｆｉｇ.５㊀Ｐｒｅｓｓｕｒｅｃｏｎｔｏｕｒｓａｔｄｉｆｆｅｒｅｎｔｃｒｏｓｓ￣ｓｅｃｔｉｏｎｌｏｃａｔｉｏｎｓ图６㊀不同截面位置处的流向速度云图Ｆｉｇ.６㊀Ｓｔｒｅａｍｗｉｓｅｖｅｌｏｃｉｔｙｃｏｎｔｏｕｒｓａｔｄｉｆｆｅｒｅｎｔｃｒｏｓｓ￣ｓｅｃｔｉｏｎｌｏｃａｔｉｏｎｓ３１气体物理２０２４年㊀第９卷(ａ)Ｕｐｐｅｒｓｕｒｆａｃｅ㊀㊀㊀㊀㊀(ｂ)Ｌｏｗｅｒｓｕｒｆａｃｅ图７㊀上下表面摩阻分布云图Ｆｉｇ.７㊀Ｆｒｉｃｔｉｏｎｃｏｅｆｆｉｃｉｅｎｔｃｏｎｔｏｕｒｓｏｎｔｈｅｕｐｐｅｒａｎｄｌｏｗｅｒｓｕｒｆａｃｅｓ４㊀不同Ｍａｃｈ数对ＨｙＴＲＶ转捩的影响保持来流湍流度ＦＳＴＩ＝０.６％不变ꎬＭａｃｈ数变化范围为３~８ꎮ图８是不同Ｍａｃｈ数条件下ＨｙＴＲＶ上下表面的摩阻分布云图ꎬ从图中可知ꎬ随着Ｍａｃｈ数的增加ꎬ上下表面的湍流区域均逐渐减少ꎬ其中上表面两侧转捩起始位置由ｘ/Ｌ＝０.５６附近后移至ｘ/Ｌ＝０.９２附近ꎬ下表面两侧转捩起始位置由ｘ/Ｌ＝０.４８附近后移至ｘ/Ｌ＝０.９９附近ꎬ上下表面两侧转捩起始位置均大幅后移ꎬ说明Ｍａｃｈ数对ＨｙＴＲＶ转捩的影响很大ꎮｕｐｐｅｒｓｕｒｆａｃｅ㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀ｌｏｗｅｒｓｕｒｆａｃｅ(ａ)Ｍａ＝３ｕｐｐｅｒｓｕｒｆａｃｅ㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀ｌｏｗｅｒｓｕｒｆａｃｅ(ｂ)Ｍａ＝４ｕｐｐｅｒｓｕｒｆａｃｅ㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀ｌｏｗｅｒｓｕｒｆａｃｅ(ｃ)Ｍａ＝５４１第２期章录兴ꎬ等:Ｍａｃｈ数和壁面温度对ＨｙＴＲＶ边界层转捩的影响ｕｐｐｅｒｓｕｒｆａｃｅ㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀ｌｏｗｅｒｓｕｒｆａｃｅ(ｄ)Ｍａ＝６ｕｐｐｅｒｓｕｒｆａｃｅ㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀ｌｏｗｅｒｓｕｒｆａｃｅ(ｅ)Ｍａ＝７ｕｐｐｅｒｓｕｒｆａｃｅ㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀ｌｏｗｅｒｓｕｒｆａｃｅ(ｆ)Ｍａ＝８图８㊀不同Ｍａｃｈ数条件下摩阻系数分布云图Ｆｉｇ.８㊀ＦｒｉｃｔｉｏｎｃｏｅｆｆｉｃｉｅｎｔｃｏｎｔｏｕｒｓａｔｄｉｆｆｅｒｅｎｔＭａｃｈｎｕｍｂｅｒｓ上表面选取图７中ｚ/Ｌ＝０.１２的位置ꎬ下表面选取ｚ/Ｌ＝０.１０的位置进行分析ꎮ从图９中可以分析出ꎬ随着Ｍａｃｈ数的增加ꎬ上表面转捩起始位置不断后移ꎬ当Ｍａｃｈ数增加到７时ꎬ由于湍流区的缩小ꎬ此处位置不再发生转捩ꎬ此外ꎬＭａｃｈ数越高层流区摩阻系数越大ꎻ下表面转捩起始位置也不断后移ꎬ当Ｍａｃｈ数增加到８时ꎬ此处位置不再发生转捩ꎬ此外ꎬＭａｃｈ数越高ꎬ湍流区的摩阻系数越小ꎬ这些结论与关于来流Ｍａｃｈ数对转捩位置影响的普遍研究结论一致ꎮ(ａ)Ｕｐｐｅｒｓｕｒｆａｃｅ㊀㊀㊀㊀㊀(ｂ)Ｌｏｗｅｒｓｕｒｆａｃｅ图９㊀不同位置摩阻系数随Ｍａｃｈ数的变化Ｆｉｇ.９㊀ＶａｒｉａｔｉｏｎｏｆｆｒｉｃｔｉｏｎｃｏｅｆｆｉｃｉｅｎｔｗｉｔｈＭａｃｈｎｕｍｂｅｒａｔｄｉｆｆｅｒｅｎｔｌｏｃａｔｉｏｎｓ５１气体物理２０２４年㊀第９卷５㊀不同壁面温度对ＨｙＴＲＶ转捩的影响保持来流湍流度ＦＳＴＩ＝０.６％及Ｍａ＝６不变ꎬ壁面温度的变化范围为１５０~９００Ｋꎮ图１０是不同壁面温度条件下ＨｙＴＲＶ上下表面的摩阻分布云图ꎬ可以看出随着壁面温度的增加ꎬ上表面两侧湍流区域先是缓慢扩大ꎬ在壁面温度为５００Ｋ时湍流区域快速缩小ꎬ增加到９００Ｋ时ꎬ已无明显湍流区域ꎻ下表面两侧湍流区域先是无明显变化ꎬ同样当壁面温度升高到５００Ｋ时ꎬ湍流区域快速缩小ꎬ当壁面温度升高到７００Ｋ时ꎬ两侧已经无明显的湍流区域ꎬ相比上表面两侧湍流区域ꎬ下表面湍流区域消失得更早ꎮ由此可以得出壁面温度对转捩的产生有较大的影响ꎬ壁面温度增加到一定程度将导致ＨｙＴＲＶ没有明显的转捩现象ꎮｕｐｐｅｒｓｕｒｆａｃｅ㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀ｌｏｗｅｒｓｕｒｆａｃｅ(ａ)Ｔ＝１５０Ｋｕｐｐｅｒｓｕｒｆａｃｅ㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀ｌｏｗｅｒｓｕｒｆａｃｅ(ｂ)Ｔ＝２００Ｋｕｐｐｅｒｓｕｒｆａｃｅ㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀ｌｏｗｅｒｓｕｒｆａｃｅ(ｃ)Ｔ＝３００Ｋｕｐｐｅｒｓｕｒｆａｃｅ㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀ｌｏｗｅｒｓｕｒｆａｃｅ(ｄ)Ｔ＝５００Ｋ６１第２期章录兴ꎬ等:Ｍａｃｈ数和壁面温度对ＨｙＴＲＶ边界层转捩的影响ｕｐｐｅｒｓｕｒｆａｃｅ㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀ｌｏｗｅｒｓｕｒｆａｃｅ(ｅ)Ｔ＝７００Ｋｕｐｐｅｒｓｕｒｆａｃｅ㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀㊀ｌｏｗｅｒｓｕｒｆａｃｅ(ｆ)Ｔ＝９００Ｋ图１０㊀不同壁面温度条件下摩阻系数分布云图Ｆｉｇ.１０㊀Ｆｒｉｃｔｉｏｎｃｏｅｆｆｉｃｉｅｎｔｃｏｎｔｏｕｒｓａｔｄｉｆｆｅｒｅｎｔｗａｌｌｔｅｍｐｅｒａｔｕｒｅｃｏｎｄｉｔｉｏｎｓ上表面选取ｚ/Ｌ＝０.１２５的位置ꎬ下表面选取ｚ/Ｌ＝０.１００的位置进行分析ꎮ从图１１中可以分析出ꎬ随着壁面温度的增加ꎬ上表面转捩起始位置先前移ꎬ当壁面温度增加到５００Ｋ时ꎬ转捩起始位置后移ꎬ转捩区长度逐渐增加ꎬ层流区域的摩阻系数逐渐增加ꎬ当壁面温度增加到７００Ｋ时ꎬ该位置已不再出现转捩ꎻ下表面转捩起始位置先小幅后移ꎬ当壁面温度增加到３００Ｋ时ꎬ转捩起始位置开始后移ꎬ当壁面温度增加到７００Ｋ时ꎬ由于湍流区域的减小ꎬ该位置不再发生转捩ꎮ(ａ)Ｕｐｐｅｒｓｕｒｆａｃｅ㊀㊀㊀㊀㊀(ｂ)Ｌｏｗｅｒｓｕｒｆａｃｅ图１１㊀不同位置摩阻系数随壁面温度的变化Ｆｉｇ.１１㊀Ｖａｒｉａｔｉｏｎｏｆｆｒｉｃｔｉｏｎｃｏｅｆｆｉｃｉｅｎｔｗｉｔｈｗａｌｌｔｅｍｐｅｒａｔｕｒｅａｔｄｉｆｆｅｒｅｎｔｌｏｃａｔｉｏｎｓ为进一步分析壁面温度的影响ꎬ本文分别在上下表面湍流区选取一点(０.９ꎬ０.０２９ꎬ０.１４)ꎬ(０.９７ꎬ－０.３４ꎬ０.１２)ꎬ分析边界层湍动能剖面ꎬ结果如图１２所示ꎮ从图中可以看到ꎬ随着壁面温度升高ꎬ边界层厚度先略微变厚ꎬ再变薄ꎬ当壁面温度升高到７００Ｋ时ꎬ边界层厚度迅速降低ꎮ这些结果与转捩位置先前移再后移的结论相符合ꎬ因为边界层厚度会影响不稳定波的时间和空间尺度ꎬ边界层厚度低时ꎬ不稳定波增长速度变慢ꎬ延迟转捩发生ꎮ需要指出的是ꎬ仅采用当前使用的方法ꎬ无法从更深层７１气体物理２０２４年㊀第９卷次揭示转捩反转的流动机理ꎬ而须另外借助稳定性分析方法ꎬ例如ꎬ使用ｅＮ方法开展基于模态的稳定性研究ꎮ文献[３３]采用该手段研究了大掠角平板钝三角翼随壁温比变化出现转捩反转的内在机理:壁温比升高促进横流模态和第１模态扰动增长ꎬ抑制第２模态发展ꎬ在第１㊁２模态联合作用影响下ꎬ出现转捩反转现象ꎮ我们将在后续开展进一步研究ꎮ(ａ)Ｕｐｐｅｒｓｕｒｆａｃｅ(ｂ)Ｌｏｗｅｒｓｕｒｆａｃｅ图１２㊀不同位置湍动能剖面随壁面温度的变化Ｆｉｇ.１２㊀Ｖａｒｉａｔｉｏｎｏｆｔｕｒｂｕｌｅｎｔｋｉｎｅｔｉｃｅｎｅｒｇｙｗｉｔｈｗａｌｌｔｅｍｐｅｒａｔｕｒｅａｔｄｉｆｆｅｒｅｎｔｌｏｃａｔｉｏｎｓ６㊀结论针对ＨｙＴＲＶ转捩问题ꎬ在Ｍａｃｈ数Ｍａ＝３~８ꎬ壁面温度Ｔ＝１５０~９００Ｋ的条件下ꎬ基于课题组自研软件ꎬ对γ￣Ｒｅ~θｔ转捩模型和ＳＳＴ湍流模型进行了高超声速修正ꎬ研究了Ｍａｃｈ数和壁面温度对ＨｙＴＲＶ转捩的影响ꎬ得出以下结论:１)经过高超声速修正后的γ￣Ｒｅ~θｔ转捩模型和ＳＳＴ湍流模型能够较为准确地预测ＨｙＴＲＶ转捩位置ꎬ并且湍流边界层区域形状与实验结果基本一致ꎻＨｙＴＲＶ存在多个不同的转捩区域ꎬ上表面两侧转捩区域分布在两侧边缘位置ꎬ下表面两侧转捩区域分布在中心线两侧ꎮ２)Ｍａｃｈ数的增加会导致上下表面转捩起始位置均大幅后移ꎬ湍流区大幅缩小ꎬ但当Ｍａｃｈ数增加到８时ꎬ湍流区仍然存在ꎬ并没有消失ꎻ上表面层流区摩阻不断增加ꎬ下表面湍流区摩阻不断减小ꎮ３)壁面温度的增加会导致上下表面转捩起始位置先前移ꎬ再后移ꎬ这与边界层厚度变化规律一致ꎬ当壁面温度增加到７００Ｋ时ꎬ下表面湍流区已经基本消失ꎬ当壁面温度增加到９００Ｋ时ꎬ上表面湍流区也基本消失ꎻ上表面在层流区域的摩阻系数逐渐增大ꎬ在湍流区的摩阻系数逐渐减小ꎮ致谢㊀感谢中国空气动力研究与发展中心和空天飞行空气动力科学与技术全国重点实验室提供的ＨｙＴＲＶ模型数据和实验数据ꎮ参考文献(Ｒｅｆｅｒｅｎｃｅｓ)[１]㊀ＯｂｅｒｉｎｇＩＩＩＨꎬＨｅｉｎｒｉｃｈｓＲＬ.Ｍｉｓｓｉｌｅｄｅｆｅｎｓｅｆｏｒｇｒｅａｔｐｏｗｅｒｃｏｎｆｌｉｃｔ:ｏｕｔｍａｎｅｕｖｅｒｉｎｇｔｈｅＣｈｉｎａｔｈｒｅａｔ[Ｊ].Ｓｔｒａ￣ｔｅｇｉｃＳｔｕｄｉｅｓＱｕａｒｔｅｒｌｙꎬ２０１９ꎬ３(４):３７￣５６. [２]ＣｈｅｎｇＣꎬＷｕＪＨꎬＺｈａｎｇＹＬꎬｅｔａｌ.Ａｅｒｏｄｙｎａｍｉｃｓａｎｄｄｙｎａｍｉｃｓｔａｂｉｌｉｔｙｏｆｍｉｃｒｏ￣ａｉｒ￣ｖｅｈｉｃｌｅｗｉｔｈｆｏｕｒｆｌａｐｐｉｎｇｗｉｎｇｓｉｎｈｏｖｅｒｉｎｇｆｌｉｇｈｔ[Ｊ].ＡｄｖａｎｃｅｓｉｎＡｅｒｏｄｙｎａｍｉｃｓꎬ２０２０ꎬ２(３):５.[３]ＢｅｒｔｉｎＪＪꎬＣｕｍｍｉｎｇｓＲＭ.Ｆｉｆｔｙｙｅａｒｓｏｆｈｙｐｅｒｓｏｎｉｃｓ:ｗｈｅｒｅｗｅᶄｖｅｂｅｅｎꎬｗｈｅｒｅｗｅᶄｒｅｇｏｉｎｇ[Ｊ].ＰｒｏｇｒｅｓｓｉｎＡｅｒｏｓｐａｃｅＳｃｉｅｎｃｅｓꎬ２００３ꎬ３９(６/７):５１１￣５３６. [４]陈坚强ꎬ涂国华ꎬ张毅锋ꎬ等.高超声速边界层转捩研究现状与发展趋势[Ｊ].空气动力学学报ꎬ２０１７ꎬ３５(３):３１１￣３３７.ＣｈｅｎＪＱꎬＴｕＧＨꎬＺｈａｎｇＹＦꎬｅｔａｌ.Ｈｙｐｅｒｓｎｏｎｉｃｂｏｕｎｄａｒｙｌａｙｅｒｔｒａｎｓｉｔｉｏｎ:ｗｈａｔｗｅｋｎｏｗꎬｗｈｅｒｅｓｈａｌｌｗｅｇｏ[Ｊ].ＡｃｔａＡｅｒｏｄｙｎａｍｉｃａＳｉｎｉｃａꎬ２０１７ꎬ３５(３):３１１￣３３７(ｉｎＣｈｉｎｅｓｅ).[５]段毅ꎬ姚世勇ꎬ李思怡ꎬ等.高超声速边界层转捩的若干问题及工程应用研究进展综述[Ｊ].空气动力学学报ꎬ２０２０ꎬ３８(２):３９１￣４０３.ＤｕａｎＹꎬＹａｏＳＹꎬＬｉＳＹꎬｅｔａｌ.Ｒｅｖｉｅｗｏｆｐｒｏｇｒｅｓｓｉｎｓｏｍｅｉｓｓｕｅｓａｎｄｅｎｇｉｎｅｅｒｉｎｇａｐｐｌｉｃａｔｉｏｎｏｆｈｙｐｅｒｓｏｎｉｃｂｏｕｎｄａｒｙｌａｙｅｒｔｒａｎｓｉｔｉｏｎ[Ｊ].ＡｃｔａＡｅｒｏｄｙｎａｍｉｃａＳｉｎｉｃａꎬ２０２０ꎬ３８(２):３９１￣４０３(ｉｎＣｈｉｎｅｓｅ).[６]ＺｈａｎｇＹＦꎬＺｈａｎｇＹＲꎬＣｈｅｎＪＱꎬｅｔａｌ.Ｎｕｍｅｒｉｃａｌｓｉ￣８１第２期章录兴ꎬ等:Ｍａｃｈ数和壁面温度对ＨｙＴＲＶ边界层转捩的影响ｍｕｌａｔｉｏｎｓｏｆｈｙｐｅｒｓｏｎｉｃｂｏｕｎｄａｒｙｌａｙｅｒｔｒａｎｓｉｔｉｏｎｂａｓｅｄｏｎｔｈｅｆｌｏｗｓｏｌｖｅｒｃｈａｎｔ２.０[Ｒ].ＡＩＡＡ２０１７￣２４０９ꎬ２０１７. [７]ＫｒａｕｓｅＭꎬＢｅｈｒＭꎬＢａｌｌｍａｎｎＪ.Ｍｏｄｅｌｉｎｇｏｆｔｒａｎｓｉｔｉｏｎｅｆｆｅｃｔｓｉｎｈｙｐｅｒｓｏｎｉｃｉｎｔａｋｅｆｌｏｗｓｕｓｉｎｇａｃｏｒｒｅｌａｔｉｏｎ￣ｂａｓｅｄｉｎｔｅｒｍｉｔｔｅｎｃｙｍｏｄｅｌ[Ｒ].ＡＩＡＡ２００８￣２５９８ꎬ２００８. [８]ＹｉＭＲꎬＺｈａｏＨＹꎬＬｅＪＬ.Ｈｙｐｅｒｓｏｎｉｃｎａｔｕｒａｌａｎｄｆｏｒｃｅｄｔｒａｎｓｉｔｉｏｎｓｉｍｕｌａｔｉｏｎｂｙｃｏｒｒｅｌａｔｉｏｎ￣ｂａｓｅｄｉｎｔｅｒｍｉｔ￣ｔｅｎｃｙ[Ｒ].ＡＩＡＡ２０１７￣２３３７ꎬ２０１７.[９]向星皓ꎬ张毅锋ꎬ袁先旭ꎬ等.Ｃ￣γ￣Ｒｅθ高超声速三维边界层转捩预测模型[Ｊ].航空学报ꎬ２０２１ꎬ４２(９):６２５７１１.ＸｉａｎｇＸＨꎬＺｈａｎｇＹＦꎬＹｕａｎＸＸꎬｅｔａｌ.Ｃ￣γ￣Ｒｅθｍｏｄｅｌｆｏｒｈｙｐｅｒｓｏｎｉｃｔｈｒｅｅ￣ｄｉｍｅｎｓｉｏｎａｌｂｏｕｎｄａｒｙｌａｙｅｒｔｒａｎｓｉｔｉｏｎｐｒｅｄｉｃｔｉｏｎ[Ｊ].ＡｃｔａＡｅｒｏｎａｕｔｉｃａｅｔＡｓｔｒｏｎａｕｔｉｃａＳｉｎｉｃａꎬ２０２１ꎬ４２(９):６２５７１１(ｉｎＣｈｉｎｅｓｅ).[１０]ＭｃＤａｎｉｅｌＲＤꎬＮａｎｃｅＲＰꎬＨａｓｓａｎＨＡ.Ｔｒａｎｓｉｔｉｏｎｏｎｓｅｔｐｒｅｄｉｃｔｉｏｎｆｏｒｈｉｇｈ￣ｓｐｅｅｄｆｌｏｗ[Ｊ].ＪｏｕｒｎａｌｏｆＳｐａｃｅｃｒａｆｔａｎｄＲｏｃｋｅｔｓꎬ２０００ꎬ３７(３):３０４￣３０９.[１１]ＰａｐｐＪＬꎬＤａｓｈＳＭ.Ｒａｐｉｄｅｎｇｉｎｅｅｒｉｎｇａｐｐｒｏａｃｈｔｏｍｏｄｅｌｉｎｇｈｙｐｅｒｓｏｎｉｃｌａｍｉｎａｒ￣ｔｏ￣ｔｕｒｂｕｌｅｎｔｔｒａｎｓｉｔｉｏｎａｌｆｌｏｗｓ[Ｊ].ＪｏｕｒｎａｌｏｆＳｐａｃｅｃｒａｆｔａｎｄＲｏｃｋｅｔｓꎬ２００５ꎬ４２(３):４６７￣４７５.[１２]ＪｕｌｉａｎｏＴＪꎬＳｃｈｎｅｉｄｅｒＳＰ.ＩｎｓｔａｂｉｌｉｔｙａｎｄｔｒａｎｓｉｔｉｏｎｏｎｔｈｅＨＩＦｉＲＥ￣５ｉｎａＭａｃｈ￣６ｑｕｉｅｔｔｕｎｎｅｌ[Ｒ].ＡＩＡＡ２０１０￣５００４ꎬ２０１０.[１３]杨云军ꎬ马汉东ꎬ周伟江.高超声速流动转捩的数值研究[Ｊ].宇航学报ꎬ２００６ꎬ２７(１):８５￣８８.ＹａｎｇＹＪꎬＭａＨＤꎬＺｈｏｕＷＪ.Ｎｕｍｅｒｉｃａｌｒｅｓｅａｒｃｈｏｎｓｕｐｅｒｓｏｎｉｃｆｌｏｗｔｒａｎｓｉｔｉｏｎ[Ｊ].ＪｏｕｒｎａｌｏｆＡｓｔｒｏｎａｕｔｉｃｓꎬ２００６ꎬ２７(１):８５￣８８(ｉｎＣｈｉｎｅｓｅ).[１４]袁先旭ꎬ何琨ꎬ陈坚强ꎬ等.ＭＦ￣１模型飞行试验转捩结果初步分析[Ｊ].空气动力学学报ꎬ２０１８ꎬ３６(２):２８６￣２９３.ＹｕａｎＸＸꎬＨｅＫꎬＣｈｅｎＪＱꎬｅｔａｌ.ＰｒｅｌｉｍｉｎａｒｙｔｒａｎｓｉｔｉｏｎｒｅｓｅａｒｃｈａｎａｌｙｓｉｓｏｆＭＦ￣１[Ｊ].ＡｃｔａＡｅｒｏｄｙｎａｍｉｃａＳｉｎｉｃａꎬ２０１８ꎬ３６(２):２８６￣２９３(ｉｎＣｈｉｎｅｓｅ).[１５]陈坚强ꎬ涂国华ꎬ万兵兵ꎬ等.ＨｙＴＲＶ流场特征与边界层稳定性特征分析[Ｊ].航空学报ꎬ２０２１ꎬ４２(６):１２４３１７.ＣｈｅｎＪＱꎬＴｕＧＨꎬＷａｎＢＢꎬｅｔａｌ.Ｃｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆｆｌｏｗｆｉｅｌｄａｎｄｂｏｕｎｄａｒｙ￣ｌａｙｅｒｓｔａｂｉｌｉｔｙｏｆＨｙＴＲＶ[Ｊ].ＡｃｔａＡｅｒｏｎａｕｔｉｃａｅｔＡｓｔｒｏｎａｕｔｉｃａＳｉｎｉｃａꎬ２０２１ꎬ４２(６):１２４３１７(ｉｎＣｈｉｎｅｓｅ).[１６]陈坚强ꎬ刘深深ꎬ刘智勇ꎬ等.用于高超声速边界层转捩研究的标模气动布局及设计方法.中国:１０９９６９３７４Ｂ[Ｐ].２０２１￣０５￣１８.ＣｈｅｎＪＱꎬＬｉｕＳＳꎬＬｉｕＺＹꎬｅｔａｌ.Ｓｔａｎｄａｒｄｍｏｄｅｌａｅｒｏ￣ｄｙｎａｍｉｃｌａｙｏｕｔａｎｄｄｅｓｉｇｎｍｅｔｈｏｄｆｏｒｈｙｐｅｒｓｏｎｉｃｂｏｕｎｄａｒｙｌａｙｅｒｔｒａｎｓｉｔｉｏｎｒｅｓｅａｒｃｈ.ＣＮꎬ１０９９６９３７４Ｂ[Ｐ].２０２１￣０５￣１８(ｉｎＣｈｉｎｅｓｅ).[１７]ＬｉｕＳＳꎬＹｕａｎＸＸꎬＬｉｕＺＹꎬｅｔａｌ.Ｄｅｓｉｇｎａｎｄｔｒａｎｓｉｔｉｏｎｃｈａｒａｃｔｅｒｉｓｔｉｃｓｏｆａｓｔａｎｄａｒｄｍｏｄｅｌｆｏｒｈｙｐｅｒｓｏｎｉｃｂｏｕｎｄａｒｙｌａｙｅｒｔｒａｎｓｉｔｉｏｎｒｅｓｅａｒｃｈ[Ｊ].ＡｃｔａＭｅｃｈａｎｉｃａＳｉｎｉｃａꎬ２０２１ꎬ３７(１１):１６３７￣１６４７.[１８]ＣｈｅｎＸꎬＤｏｎｇＳＷꎬＴｕＧＨꎬｅｔａｌ.Ｂｏｕｎｄａｒｙｌａｙｅｒｔｒａｎ￣ｓｉｔｉｏｎａｎｄｌｉｎｅａｒｍｏｄａｌｉｎｓｔａｂｉｌｉｔｉｅｓｏｆｈｙｐｅｒｓｏｎｉｃｆｌｏｗｏｖｅｒａｌｉｆｔｉｎｇｂｏｄｙ[Ｊ].ＪｏｕｒｎａｌｏｆＦｌｕｉｄＭｅｃｈａｎｉｃｓꎬ２０２２ꎬ９３８(４０８):Ａ８.[１９]ＱｉＨꎬＬｉＸＬꎬＹｕＣＰꎬｅｔａｌ.Ｄｉｒｅｃｔｎｕｍｅｒｉｃａｌｓｉｍｕｌａｔｉｏｎｏｆｈｙｐｅｒｓｏｎｉｃｂｏｕｎｄａｒｙｌａｙｅｒｔｒａｎｓｉｔｉｏｎｏｖｅｒａｌｉｆｔｉｎｇ￣ｂｏｄｙｍｏｄｅｌＨｙＴＲＶ[Ｊ].ＡｄｖａｎｃｅｓｉｎＡｅｒｏｄｙｎａｍｉｃｓꎬ２０２１ꎬ３(１):３１.[２０]万兵兵ꎬ陈曦ꎬ陈坚强ꎬ等.三维边界层转捩预测ＨｙＴＥＮ软件在高超声速典型标模中的应用[Ｊ].空天技术ꎬ２０２３(１):１５０￣１５８.ＷａｎＢＢꎬＣｈｅｎＸꎬＣｈｅｎＪＱꎬｅｔａｌ.ＡｐｐｌｉｃａｔｉｏｎｓｏｆＨｙＴＥＮｓｏｆｔｗａｒｅｆｏｒｐｒｅｄｉｃｔｉｎｇｔｈｒｅｅ￣ｄｉｍｅｎｓｉｏｎａｌｂｏｕｎｄａｒｙ￣ｌａｙｅｒｔｒａｎｓｉｔｉｏｎｉｎｔｙｐｉｃａｌｈｙｐｅｒｓｏｎｉｃｍｏｄｅｌｓ[Ｊ].ＡｅｒｏｓｐａｃｅＴｅｃｈｎｏｌｏｇｙꎬ２０２３(１):１５０￣１５８(ｉｎＣｈｉｎｅｓｅ). [２１]ＭｅｎｔｅｒＦＲꎬＬａｎｇｔｒｙＲＢꎬＬｉｋｋｉＳＲꎬｅｔａｌ.Ａｃｏｒｒｅｌａｔｉｏｎ￣ｂａｓｅｄｔｒａｎｓｉｔｉｏｎｍｏｄｅｌｕｓｉｎｇｌｏｃａｌｖａｒｉａｂｌｅｓ ＰａｒｔⅠ:ｍｏｄｅｌｆｏｒｍｕｌａｔｉｏｎ[Ｊ].ＪｏｕｒｎａｌｏｆＴｕｒｂｏｍａｃｈｉｎｅｒｙꎬ２００６ꎬ１２８(３):４１３￣４２２.[２２]ＬａｎｇｔｒｙＲＢꎬＭｅｎｔｅｒＦＲꎬＬｉｋｋｉＳＲꎬｅｔａｌ.Ａｃｏｒｒｅｌａｔｉｏｎ￣ｂａｓｅｄｔｒａｎｓｉｔｉｏｎｍｏｄｅｌｕｓｉｎｇｌｏｃａｌｖａｒｉａｂｌｅｓ ＰａｒｔⅡ:ｔｅｓｔｃａｓｅｓａｎｄｉｎｄｕｓｔｒｉａｌａｐｐｌｉｃａｔｉｏｎｓ[Ｊ].ＪｏｕｒｎａｌｏｆＴｕｒ￣ｂｏｍａｃｈｉｎｅｒｙꎬ２００６ꎬ１２８(３):４２３￣４３４.[２３]ＬａｎｇｔｒｙＲＢꎬＭｅｎｔｅｒＦＲ.Ｃｏｒｒｅｌａｔｉｏｎ￣ｂａｓｅｄｔｒａｎｓｉｔｉｏｎｍｏｄｅｌｉｎｇｆｏｒｕｎｓｔｒｕｃｔｕｒｅｄｐａｒａｌｌｅｌｉｚｅｄｃｏｍｐｕｔａｔｉｏｎａｌｆｌｕｉｄｄｙｎａｍｉｃｓｃｏｄｅｓ[Ｊ].ＡＩＡＡＪｏｕｒｎａｌꎬ２００９ꎬ４７(１２):２８９４￣２９０６.[２４]孟德虹ꎬ张玉伦ꎬ王光学ꎬ等.γ￣Ｒｅθ转捩模型在二维低速问题中的应用[Ｊ].航空学报ꎬ２０１１ꎬ３２(５):７９２￣８０１.ＭｅｎｇＤＨꎬＺｈａｎｇＹＬꎬＷａｎｇＧＸꎬｅｔａｌ.Ａｐｐｌｉｃａｔｉｏｎｏｆγ￣Ｒｅθｔｒａｎｓｉｔｉｏｎｍｏｄｅｌｔｏｔｗｏ￣ｄｉｍｅｎｓｉｏｎａｌｌｏｗｓｐｅｅｄｆｌｏｗｓ[Ｊ].ＡｃｔａＡｅｒｏｎａｕｔｉｃａｅｔＡｓｔｒｏｎａｕｔｉｃａＳｉｎｉｃａꎬ２０１１ꎬ３２(５):７９２￣８０１(ｉｎＣｈｉｎｅｓｅ).[２５]牟斌ꎬ江雄ꎬ肖中云ꎬ等.γ￣Ｒｅθ转捩模型的标定与应用[Ｊ].空气动力学学报ꎬ２０１３ꎬ３１(１):１０３￣１０９.ＭｏｕＢꎬＪｉａｎｇＸꎬＸｉａｏＺＹꎬｅｔａｌ.Ｉｍｐｌｅｍｅｎｔａｔｉｏｎａｎｄｃａｌｉｂｅｒａｔｉｏｎｏｆγ￣Ｒｅθｔｒａｎｓｉｔｉｏｎｍｏｄｅｌ[Ｊ].ＡｃｔａＡｅｒｏｄｙ￣ｎａｍｉｃａＳｉｎｉｃａꎬ２０１３ꎬ３１(１):１０３￣１０９(ｉｎＣｈｉｎｅｓｅ). [２６]郭隽ꎬ刘丽平ꎬ徐晶磊ꎬ等.γ￣Ｒｅ~θｔ转捩模型在跨声速涡轮叶栅中的应用[Ｊ].推进技术ꎬ２０１８ꎬ３９(９):１９９４￣２００１.９１气体物理２０２４年㊀第９卷ＧｕｏＪꎬＬｉｕＬＰꎬＸｕＪＬꎬｅｔａｌ.Ａｐｐｌｉｃａｔｉｏｎｏｆγ￣Ｒｅ~θｔｔｒａｎ￣ｓｉｔｉｏｎｍｏｄｅｌｉｎｔｒａｎｓｏｎｉｃｔｕｒｂｉｎｅｃａｓｃａｄｅｓ[Ｊ].ＪｏｕｒｎａｌｏｆＰｒｏｐｕｌｓｉｏｎＴｅｃｈｎｏｌｏｇｙꎬ２０１８ꎬ３９(９):１９９４￣２００１(ｉｎＣｈｉｎｅｓｅ).[２７]郑赟ꎬ李虹杨ꎬ刘大响.γ￣Ｒｅθ转捩模型在高超声速下的应用及分析[Ｊ].推进技术ꎬ２０１４ꎬ３５(３):２９６￣３０４.ＺｈｅｎｇＹꎬＬｉＨＹꎬＬｉｕＤＸ.Ａｐｐｌｉｃａｔｉｏｎａｎｄａｎａｌｙｓｉｓｏｆγ￣Ｒｅθｔｒａｎｓｉｔｉｏｎｍｏｄｅｌｉｎｈｙｐｅｒｓｏｎｉｃｆｌｏｗ[Ｊ].ＪｏｕｒｎａｌｏｆＰｒｏｐｕｌｓｉｏｎＴｅｃｈｎｏｌｏｇｙꎬ２０１４ꎬ３５(３):２９６￣３０４(ｉｎＣｈｉ￣ｎｅｓｅ).[２８]孔维萱ꎬ阎超ꎬ赵瑞.γ￣Ｒｅθ模式应用于高速边界层转捩的研究[Ｊ].空气动力学学报ꎬ２０１３ꎬ３１(１):１２０￣１２６.ＫｏｎｇＷＸꎬＹａｎＣꎬＺｈａｏＲ.γ￣Ｒｅθｍｏｄｅｌｒｅｓｅａｒｃｈｆｏｒｈｉｇｈ￣ｓｐｅｅｄｂｏｕｎｄａｒｙｌａｙｅｒｔｒａｎｓｉｔｉｏｎ[Ｊ].ＡｃｔａＡｅｒｏｄｙ￣ｎａｍｉｃａＳｉｎｉｃａꎬ２０１３ꎬ３１(１):１２０￣１２６(ｉｎＣｈｉｎｅｓｅ). [２９]张毅锋ꎬ何琨ꎬ张益荣ꎬ等.Ｍｅｎｔｅｒ转捩模型在高超声速流动模拟中的改进及验证[Ｊ].宇航学报ꎬ２０１６ꎬ３７(４):３９７￣４０２.ＺｈａｎｇＹＦꎬＨｅＫꎬＺｈａｎｇＹＲꎬｅｔａｌ.ＩｍｐｒｏｖｅｍｅｎｔａｎｄｖａｌｉｄａｔｉｏｎｏｆＭｅｎｔｅｒᶄｓｔｒａｎｓｉｔｉｏｎｍｏｄｅｌｆｏｒｈｙｐｅｒｓｏｎｉｃｆｌｏｗｓｉｍｕｌａｔｉｏｎ[Ｊ].ＪｏｕｒｎａｌｏｆＡｓｔｒｏｎａｕｔｉｃｓꎬ２０１６ꎬ３７(４):３９７￣４０２(ｉｎＣｈｉｎｅｓｅ).[３０]ＬａｎｇｔｒｙＲＢꎬＳｅｎｇｕｐｔａＫꎬＹｅｈＤＴꎬｅｔａｌ.Ｅｘｔｅｎｄｉｎｇｔｈｅγ￣Ｒｅθｔｃｏｒｒｅｌａｔｉｏｎｂａｓｅｄｔｒａｎｓｉｔｉｏｎｍｏｄｅｌｆｏｒｃｒｏｓｓｆｌｏｗｅｆｆｅｃｔｓ(Ｉｎｖｉｔｅｄ)[Ｒ].ＡＩＡＡ２０１５￣２４７４ꎬ２０１５. [３１]ＳａｒｋａｒＳ.Ｔｈｅｐｒｅｓｓｕｒｅ￣ｄｉｌａｔａｔｉｏｎｃｏｒｒｅｌａｔｉｏｎｉｎｃｏｍｐｒｅｓｓｉ￣ｂｌｅｆｌｏｗｓ[Ｊ].ＰｈｙｓｉｃｓｏｆＦｌｕｉｄｓＡꎬ１９９２ꎬ４(１２):２６７４￣２６８２.[３２]ＷｉｌｃｏｘＤＣ.Ｄｉｌａｔａｔｉｏｎ￣ｄｉｓｓｉｐａｔｉｏｎｃｏｒｒｅｃｔｉｏｎｓｆｏｒａｄｖａｎｃｅｄｔｕｒｂｕｌｅｎｃｅｍｏｄｅｌｓ[Ｊ].ＡＩＡＡＪｏｕｒｎａｌꎬ１９９２ꎬ３０(１１):２６３９￣２６４６.[３３]马祎蕾ꎬ余平ꎬ姚世勇.壁温对钝三角翼边界层稳定性及转捩影响[Ｊ].空气动力学学报ꎬ２０２０ꎬ３８(６):１０１７￣１０２６.ＭａＹＬꎬＹｕＰꎬＹａｏＳＹ.Ｅｆｆｅｃｔｏｆｗａｌｌｔｅｍｐｅｒａｔｕｒｅｏｎｓｔａｂｉｌｉｔｙａｎｄｔｒａｎｓｉｔｉｏｎｏｆｈｙｐｅｒｓｏｎｉｃｂｏｕｎｄａｒｙｌａｙｅｒｏｎａｂｌｕｎｔｄｅｌｔａｗｉｎｇ[Ｊ].ＡｃｔａＡｅｒｏｄｙｎａｍｉｃａＳｉｎｉｃａꎬ２０２０ꎬ３８(６):１０１７￣１０２６(ｉｎＣｈｉｎｅｓｅ).０２。
Unit 4 The Lady on Pemberton Street Review of Vocabulary for Unit 31. 转化2. 堆起来3. 影响4. 隔绝5. 随意的；偶然的6. 拆毁7. 时尚8. 处理掉9. 垃圾10. 可行性11. 一贯地12. 控制；抑制1. divert sidetrack2. stack to pile3. impact to influence4. insulate to prevent or reduce the transmission of electricity, heat, or sound to or from (a body, device, or region) by surrounding with a non-conducting material; protecthappening by accident or chance6. demolition destruction7. fad fashion; craze8. discard to get rid of as useless or undesirable9. garbage worthless, useless, or unwanted matter; rubbish discarded or waste matter 10. viability practicability (of living things) capable of normal growth and development11. consistently regularly; systematically12. hold down to restrain or controlSome related questions1. How is it alike to Unit 3 in theme?2. What is Mable like?a. she is at least in her 65, bright eyes between fierce and merry, thin but not frailb. she is a warm-hearted woman though sometimes tough with litter- throwers.c. Mable kept on sweeping the street regardless of the dreadful weather.About the storyProtecting the environment seems a big and sometimes abstract problem, but it does concern us all. With the disappearing of ozone layer above two poles, the frequent occurrence of acid rain and the sandstorm, environmental problems keptthe attention of the scientists as well as the mon people.The main idea of the textMable is definitely one of those people who consciously protect the environment. Her decades' practice of cleaning the block has inspired many people around her to pay more attention to the environment issues and be a conscious cleaner. Have you ever noticed any examples of environmental heroes around you?Text StructureRead the text thoroughly and prehend the discourse by dividing it into several parts: Mee t—the clean sweep—the alley gate—the block cleaning—the “debt〞Words and Phrases:Unit 4K ey Words1. dilapidated: collapsing2. reedy: shrill, loud and unpleasant to hear3. luscious: delicious, attractive4. genuinely: really, truly, authentically5. mence: start6. admonish: advise, persuade7. incongruous: inharmonious8. infectious: contagious9. festive: joyful10. skeletal: skinny, bony11. bativeness: aggressiveness12. insomnia: sleeplessness13. vacant: empty14. a rap at the door: a knock at the door 16. a sheaf of advertising circularsThe Lady on Pemberton Street潘伯敦街上的女士by Albert DiBartolomeo艾伯特▪迪巴特罗门Shortly after the author and his wife move to a house on a little street calledPemberton, they get acquainted with a special neighbor －Mable Howard, who has battled all her life against litter, decay and disorder to make life more enchanting in the neighborhood. Here is the moving story of Mable Howard, the beloved block captain.作者与妻子搬到一条叫作潘伯顿的小街上居住后不久,就结识了一位特殊的邻居-- 梅布尔▪霍华德。
AN HST ACS/WFC H IMAGING SURVEYOF NEARBY GALAXIESRolf A.JansenDept.of Physics and Astronomy,Arizona State University,Box871504,Tempe,AZ85287-1504 Email:Rolf.Jansen@Abstract Previous studies of nearby galaxies show large discrepancies between different star formation(SF)indicators on large(100pc,or even global)scales:thestrikingly complex interplay of young stars,dust and ionized gas are the primarycause of this variance.The few galaxies in the HST Archive with both H andmid-UV images show this complex geometry to extend down to pc scales.To provide a benchmark for understanding SF processes at spatial resolutionsthat are unattainable from the ground in normal and star-bursting,barred andnon-barred galaxies,I am conducting an H SNAPshot survey with ACS/WFCof24galaxies of all Hubble types,that are nearby but beyond the Local Groupand that were previously imaged with HST in the mid-UV and red.These data can be used to address a wide range of astrophysical problems,butthe immediate goals are to:(1)spatially resolve the dust clouds andfilamentswhich strongly affect mid-UV and H derived SF rates,(2)test how the large-scale correlation between H and mid-UVflux breaks down on pc scales,and(3)model the propagation of star formation by comparing the SF over time scalesof100Myr(via mid-UV)and5Myr(via H).This will(4)significantlyimprove our insight into,and calibration of SF in UV-bright galaxies at high,and into the cosmic SF history.Keywords:Galaxies:star formation—galaxies:ISM—galaxies:fundamental parameters —galaxies:nearbyQuantitative Star Formation TracersAccurate measurements of star formation(SF)in external galaxies based on tracers like the mid-UV continuum,H recombination line,[O]emission line,and radio continuum emission are hampered by systematic uncertainties due to the presence of interstellar dust.This dust is intermixed with interstellar gas and distributed in highly complex geometries down to scales that have only been resolved from the ground in the very nearest Lo-cal Group galaxies but are readilly apparent in HST images.In their ground-based spectrophotometric study,Jansen et al.showed strong2Figure1.H images of star-bursting dwarf(IBm)galaxy NGC1140obtained from the ground under good conditions(V ATT,Mt.Graham;=09)and obtained as part of the ACS/WFC SNAPshot survey.The large uncertainties and discrepancies in global SFR calibra-tions can only be resolved by studying the tracers most sensitive to dust in a diverse nearby galaxy sample at HST resolution.correlations between a galaxy’s Hubble type,wavelength-dependent morphology,luminosity and global emission line strengths of[O]and H (hence the global star formation rate[SFR]),demonstrating the need for a rel-atively large and varied galaxy sample.However,ground-based studies are significantly limited by the seeing(04),both in imaging and spectroscopy, and are therefore not suited for the study of individual SF sites beyond the Local Group.Since the emission emerging from a galaxy,especially in the UV,is dominated by regions of low obscuration and may itself depend on the SFR,the resulting large uncertainties and discrepancies in global SFR calibrations can only be resolved by studying the tracers most sensitive to dust in a diverse nearby galaxy sample at HST resolution.An ACS/WFC H SNAPshot survey of Nearby GalaxiesIn Cycles9+10,Windhorst et al.imaged a sample of89nearby galaxies with WFPC2in the mid-UV F300W and red F814Wfilters supplement-ing the17galaxies in the HST Archive for which such images were already available.The combined sample spans the Hubble sequence in morphologi-cal type,and is well represented in late-type/irregular,merging and interacting galaxies which are more common at higher redshifts.Jansen et al.are currently conducting an ACS/WFC H SNAPshot survey (PID#9892)of nearby galaxies selected from this sample.48nearby galax-ies were selected with km s,sampling different SF environments, for which sufficient S/N could be obtained in the F658N Hfilter in a par-HST/ACS H Images of Nearby Galaxies3 tial HST orbit,and without prior WFPC2H images of acceptable quality in the Archive.I chose to aim for the longer holes in the HST schedule(32–55min)to ensure well-exposed H images and sensitivity to faint extended emission,even though fewer such opportunities are available.It allowedfit-ting three WFC exposures within a SNAP visit and therefore to also obtain a short F625W()exposure for continuum subtraction and to aid in select-ing low-extinction sightlines(see below).As of this writing(May2004),19 galaxies were imaged and by the end of Cycle12this should be a random sub-set of50%of the pool of48targets.The ACS/WFC H SNAPshots provide both exquisite spatial resolution and spectral information in one of the most important atomic emission lines,that has not been mapped yet in a significant number of galaxies with HST images in both H and the mid-UV. Science goals for the H survey(1)Measure the intrinsic correlation of H and mid-UVflux as tracers of current high mass star formation,by distinguishing low and high extinction sight-lines at10pc spatial resolution.We will model the Lyman contin-uum luminosity and corresponding high-mass SFR for the the sight-lines with the very lowest extinction(as determined from comparison of the F300W, F625W,and F814W images)—taking into account possible changes in recent SF history or spatial propagation of the SF—and so constrain the ratio of H to mid-UVflux to be used in SF calibration at high.We will study whether that ratio varies as a function of a galaxy’s Hubble type,or whether it depends on(a)the distance from the galaxy center(e.g.,metallicity gradients),(b)the size or luminosity of a H-region,(c)local morphological structures,like bars, spiral arms,ridges,bubbles orfilaments,and(d)on the proximity to other H-regions.(2)Measure the effect of averaging over sight-lines with varying dust column densities on the derived star formation rates,calibrate lower resolution mea-surements,and model the SFR calibrations at higher redshifts.The effects of dust,age and metallicity are extremely difficult to disentangle.The high spatial resolution of ACS/WFC,however,helps significantly(its005pixels equal to10pc out to37Mpc).For the more extinguished sight-lines,we will test the interstellar extinction law with simple assumptions on the dust geometry,for a much larger and more varied sample of galaxies than entered these studies,using the intrinsic H–mid-UVflux-ratios measured along the most transparent sightlines as reference.We will then measure the impact of averaging over varying dust column densities on the derived SFRs and properly model the SFR calibration at high,taking into account the metal production history.Studies with this kind of detail have so far been possible only in Local Group galaxies.This study will complement the latter(which compared4Figure2.Detail of the full ACS/WFC H image of NGC1140centered on the high surface brightness“main body”or“bar”portion of the galaxy.Thefilamentary nature of the distribution of the H emission is apparent down to the smallest scales(5pc).UIT mid-and far-UV imagery with ground-based H at3resolution)by spatially resolving individual SF sites.(3)Investigate whether the stellar populations responsible for the mid-UV emission coincide spatially with those responsible for exciting the H I gas. Available(lower resolution)images of nearby galaxies show distinctive spatial distributions for H and mid-UV light.The high spatial resolution attainable with ACS/WFC allows us to examine to what extent this trend continues down to pc scales:because of different timescales probed by mid-UV and H light, this gives powerful insight into the mechanisms by which SF propagates within galaxies on time-scales100Myr.It also gives us the opportunity to study in detail the fraction of H emitted by diffuse ionized gas,and to study out-flows,bubbles and superbubbles driven by SNe that have recently exploded in or near H-regions(as seen in the H image of NGC5253).(4)Probe the faint end of the H II-region LF—do size and luminosity de-pend on galaxy type?.We will measure whether the faint-end slope of the H-region LF depends on galaxy morphology—and if so,how—and,by comparing diameters and luminosities,what fraction of H-regions is density bounded.For example,Kennicutt et al.and Caldwell et al.find system-atic changes in the shape of the H-region LF with Hubble type,as would re-sult from differences in the intrinsic molecular cloud mass spectrum.The high end of the mass spectrum is sensitive to shear due to differential rotation,andHST/ACS H Images of Nearby Galaxies5Figure3.Detail of the full ACS/WFC H image of NGC1140centered on the“tail”of the galaxy.The knots of star formation visible in the ground based image(Fig.1a)are resolved into the brightest stars and/or compact young clusters.so a dependence on Hubble type could naturally emerge.Beckman et al.find that the H-region LF in several disk galaxies with Cepheid distances shows “glitches”near an apparently invariant luminosity of L H.We will investigate to what extent these results are due to the limited spatial resolution in these studies.AcknowledgementsThe author gratefully acknowledges support from NASA grant GO-9892and thanks the team of co-Is of this program.References[1]Beckman et al.2000,AJ119,2728[2]Bell&de Jong2000,MNRAS312,497[3]Bell&Kennicutt2001,ApJ548,681[4]Bell et al.2002,ApJ565,994[5]Bell2002,ApJ577,150[6]Caldwell et al.1991,ApJ370,526[7]Calzetti et al.1994,ApJ429,582[8]Calzetti et al.1997,AJ114,1834[9]Calzetti2001,PASP113,1449[10]Cardelli et al.1989,ApJ345,245[11]Clarke&Oey2002,MNRAS337,1299[12]de Grijs et al.2001,AJ121,768[13]Jansen2000,Ph.D.Thesis(Univ.of Groningen)[14]Jansen et al.2000a,ApJS126,271[15]Jansen et al.2000b,ApJS126,331[16]Jansen et al.2001,ApJ551,825[17]Jansen et al.2004,ApJS(in prep.)[18]Kennicutt1983,ApJ272,54[19]Kennicutt et al.1989,ApJ337,761[20]Kennicutt1998,ARA&A36,189[21]Leitherer2001,in:“The Central kpc ofStarbursts and AGN”,p.457[22]Macri et al.2001,ApJ549,721[23]Martin1997,ApJ491,561[24]Martin&Kennicutt1997,ApJ483,698[25]Oey&Kennicutt1997,MNRAS291,827[26]Sullivan et al.2000,MNRAS312,442[27]Sullivan et al.2001,ApJ558,72[28]Windhorst et al.2002,ApJS143,113。
a r X i v :a s t r o -p h /0503258v 2 17 M a r 2005Mon.Not.R.Astron.Soc.000,1–??(2002)Printed 2February 2008(MN La T E X style file v2.2)The Redshift-Space Two Point Correlation Function ofELAIS-S1GalaxiesV.D’Elia,1E.Branchini, Franca,2V.Baccetti,2I.Matute,3F.Pozzi,4C.Gruppioni 51INAF-Osservatorio Astronomico di Roma via Frascati 33,Monteporzio-Catone (RM),I-00040Italy2Dipartimentodi Fisica,Universit´a degli Studi “Roma Tre”,Via della Vasca Navale 84,I-00146,Roma,Italy3Max-Planck Institut f¨u r extraterrestrische Physik (MPE),Giessenbachstrasse,Postfach 1312,85741Garching,Germany 4Dipartimento di Astronomia,Universit`a di Bologna,viale Berti Pichat 6,I-40127Bologna,Italy 5INAF-Osservatorio Astronomico di Bologna,via Ranzani 1,I-40127Bologna,ItalyReleased 2005January 14ABSTRACTWe investigate the clustering properties of galaxies in the recently completed ELAIS-S1redshift survey through their spatial two point autocorrelation function.We used a sub-sample of the ELAIS-S1catalog covering approximately 4deg 2and consisting of 148objects selected at 15µm with a flux >0.5mJy and redshift z <0.5.We detected a positive signal in the correlation function that,in the range of separations 1−10h −1Mpc is well approximated by a power law with a slope γ=1.4±0.25and a correlation length s 0=5.4±1.2h −1Mpc,at the 90%significance level.This result is in good agreement with the redshift-space correlation function measured in more local samples of mid infrared selected galaxies like the IRAS PSC z redshift survey.This suggests a lack of significant clustering evolution of infrared selected objects out to z =0.5that is further confirmed by the consistency found between the correlation functions measured in a local (z <0.2)and a distant (0.2<z <0.5)subsample of ELAIS-S1galaxies.We also confirm that optically selected galaxies in the local redshift surveys,especially those of the SDSS sample,are significantly more clustered than infrared objects.Key words:galaxies:clusters:general -galaxies:evolution -cosmology:observation -Large scale structure of Universe -infrared:galaxies1INTRODUCTIONInvestigating the redshift-space distribution of galaxies has long been regarded as a fundamental aspect of observational cosmology.The primary statistical tool for characterizing galaxy clustering is the spatial two point correlation func-tion,ξ(s )since,in the current paradigm of structure for-mation,the galaxy two-point correlation function is directly related to the initial power spectrum of mass density fluc-tuations.This is true as long as galaxies trace the underlying mass density field.However,it is now well established that the clustering of galaxies at low redshift depends on a vari-ety of factors,implying that not all types of galaxies can be regarded as unbiased mass tracers.The clustering of opti-cally selected galaxies has been found to depend on galaxy luminosity (Norberg et al.2002and reference therein),mor-phological and spectral type (Hermit et al.1996,Zehavi et al.2002,Magdwick et al.2003).On the other hand,the clustering of infrared selected galaxies seems to depend ontheir infrared color (Hawkins et al.2001)rather than on luminosity (Szapudi et al.2000).The evidence that different galaxy populations might give different biased pictures of the mass distribution has complicated but also enriched the interpretation of galaxy clustering.Indeed,the very fact that the spatial clustering of galaxies is related to their physical properties represents an important observational test for all theories of galaxy for-mation.In particular,strong constraints on galaxy evolution models can be obtained by measuring the relative clustering of different extragalactic objects as a function of redshifts,for which very deep galaxy samples are required.Several deep redshift surveys of optically selected galax-ies,like the Keck surveys of the GOODS-north (Wirth et al.2004)and GOODS-south (Vanzella et al.2004)fields and the DEEP2redshift survey (Davis et al.2003),are cur-rently being performed.First results based on early data look very promising indeed.The analysis of Coil et al.(2004)has shown that the two-point correlation function of DEEP2galaxies with a median redshift z =1.14is consistent with2V.D’Elia et al.that measured by Adelberger et al.(2003)in a very deep (z∼3)sample of Lyman break galaxies but is significantly smaller than the correlation measured in the local(z∼0) 2dF galaxy sample.Since2dF b j-selected galaxies are known to trace the underlying mass densityfield in a unbiased way (Verde et al.2002,Lahav et al.2002),the smaller correla-tion measured in DEEP2survey implies that this is not a strongly biased sample of objects either,since the clustering of the dark mass is expected to decrease with redshift in a similar way(Coil et al.2004).Mid-infrared selected galaxies also constitutes a very in-teresting population of objects since they are also known to trace the underlying mass distribution in the local universe in an almost unbiased fashion.More precisely,it has been found that thefluctuations in their number density,δg is related to the underlying mass overdensityfieldδm through a simple,linear biasing relationδg∼1.2δm(Tegmark,Zal-darriaga&Hamilton2001and Taylor et al.2002).Another reason why mid-infrared selection is interesting is that lu-minosity in this band is approximately proportional to star-formation rate(independent of dust),thus a mid-infrared sample of galaxies will highlight the distribution of star-formation activity at a particular epoch.Clearly,it would be very important to quantify the clustering evolution of mid-infrared selected objects and compare it with that of optically selected galaxies.This is indeed the main goal of this work in which we analyze the clustering properties of sample of mid-infrared selected galaxies extracted from the ELAIS redshift survey(Oliver et al.2000)and extend-ing out to a redshift z=0.5.According to La Franca et al.(2004),two main spectroscopic classes have been found to dominate the extragalactic population of these objects: star-forming galaxies(from absorbed to extreme starbursts:νLν(15µm)∼108−1011L⊙),which account for75%of the sources,and active galactic nuclei(excluded from this anal-ysis)which account for25%of the sources.About20%of the extragalactic ELAIS sources are dust-enshrouded star-burst galaxies,while passive galaxies are essentially absent from the sample.Our analysis is performed in redshift-space and thus complements the previous work of Gonzalez-Solares et al.. (2004)who measured the angular correlation properties of a similar sample of ELAIS galaxies that from which they have inferred their spatial correlation properties.The outline of this paper is as follows.In section2we describe the ELAIS-S1galaxy redshift survey that we an-alyze in this work.In section3we discuss our method of estimating the two-point correlation function,assess its ro-bustness and evaluate its statistical uncertainties.The main results are presented in section4,and discussed in section 5,in which we also draw our main conclusions.2THE ELAIS S1SAMPLEThe European Large-Area ISO survey(ELAIS,Oliver et al. 2000;Rowan-Robinson et al.2004)is the largest Open Time programme conducted by the ISO satellite(Kessler et al. 1996).It covers an area of12deg2,divided in fourfields (N1,N2and N3in the northern hemisphere and S1in the southern one)distributed across the sky in order to de-crease the biases due to cosmic variance.The survey bands are at6.7,15,90and170µm;the15µm one presents the highest density of galaxies(Serjeant et al.2000,Gruppioni et al.2002,La Franca et al.2004),making it the best choice for a study of their clustering properties.In this work we concentrate on the southern area,S1.This survey is made of nine raster observations,each covering40×40arcmin2.Thefinal analysis catalog at15µm in the S1field has been released by Lari et al.(2001) covering an area of2×2deg2centered atα(2000)=00h 34m44.4s,δ(2000)=−43◦28′12′′.It includes462mid-IR sources down to aflux limit of0.5mJy.We have restricted our analysis to a highly reliable subsample of406objects (La Franca et al.2004).A detailed description of the optical classification of the ELAIS-S1sources,size and completeness function of the ar-eas used in our study,as well as the observed counts for each class of sources(normal galaxies,Starburst galaxies and AGN)are presented by La Franca et al.(2004).The mea-sure of the evolution of star-forming galaxies has been inves-tigated by Pozzi et al.(2004)and Gruppioni et al.(2005), while afirst estimate of the luminosity function for type-1 AGN has been presented by Matute et al.(2002)1.The central raster,S1R5)which covers0.55deg2and reaches a20%completeness atfluxes of 0.7mJy,and b)the remaining area(S1R5raster and the remaining100galaxies to the surrounding areas S1R5raster.The continuous line histograms in both panels of Fig. 2shows the redshift distribution of the ELAIS-S1galaxies in the S1Rest(bottom)rasters.Gonzalez-Solares et al..(2004)have shown that the redshift distri-bution of ELAIS objects obtained from follow-up spectro-scopic observations and photometric redshifts is consistent with that predicted from the ELAIS luminosity function of Pozzi et al.(2004).This redshift distribution will used in the next section to estimate the galaxy correlation function and to construct the mock ELAIS catalogs.1Data and related papers about the ELAIS southern survey are available at:http://www.fis.uniroma3.it/∼ELAISMonthly Notices:L a T E X2εguide for authors3Figure 1.The angular distribution of ELAIS-S1sources.Thesolid square is the central raster S1R5raster(top panel)and in S1n RN RR(s) n R N RR(s)4V.D’Elia et al. w i=1H o z0dz′Ωm(1+z′)3+ΩΛ,(3)where r is the comoving distance,and then added the line of sight component of the particle peculiar velocity.Finally, a population of mock galaxies have been extracted from the particles through a Montecarlo rejection procedure designed to match the observed redshift distribution of real ELAIS galaxies in both the inner40×40arcmin2S1Rest-like samples.This procedure has been re-peated to obtain30mock ELAIS-S1samples,containing Figure3.Averageξ(s)measured in the30mock ELAIS-S1cata-logs(filled dots)and the rms scatter around the mean(errorbars). Open dots shows the“true”ξ(s)of all particles in the simulation contained in a region with the same volume of the ELAIS-S1 sample.The straight line represents the best power lawfit to the “true”ξ(s)in the range1−10h−1Mpc.The values of the best fit parameters are also shown.∼120objects each,for which we have evaluated the two-point correlation function.The mean redshift distribution of fake objects in the30catalogs is shown in of Fig.2(dashed line histogram)for the S1Rest(bot-tom)rastersThefilled dots in Fig.3shows the averageξ(s)in the 30mock catalogs.The errorbars represent the rms scatter around the mean values.They constitutes our estimate of er-rors in the measurement of two point correlation function of the real ELAIS-S1galaxies These errors account for cosmic variance and sample noise,that constitutes the main source of uncertainty.The large size of the sample guarantees that the’integral constraint’correction is only5%(Gonzalez-Solares et al.2004)and thus can be neglected in the error budget.The open dots in Fig.3shows the“true”ξ(s)of the simulation,measured by considering all particles in one of our ELAIS-like samples.The“true”ξ(s)is consistent with the averageξ(s)of the mocks,indicating that our method for estimatingξ(s)is indeed unbiased.The mock ELAIS-S1catalogs mimic the geometry and selection effects of the real sample and account for the spa-tial clustering and its evolution in aflatΛCDM universe. However,they are not guaranteed to reproduce the cluster-ing properties of the ISO galaxies unless,of course,these trace the underlying mass densityfield out to z=0.5.As we have verified a posteriori this is indeed the case, in the sense that the“true”ξ(s)in the range1−10h−1Mpc is well approximated by a power law whose bestfit param-eters,displayed in Fig.3are consistent within the errors with those determined in the analysis of the real ELAIS-S1 sample presented in the following section.Monthly Notices:La T E X 2εguide for authors5Figure 4.The redshift-space correlation function for the ELAIS-S1galaxy sample (filled dots).Error bars have been calculatedusing the 30ELAIS-like mock catalogs.The solid line represents the power law best fit ξ(s )=(s/s 0)−γto the data in the range 1−10h −1Mpc.The best fit parameters are indicated in the plot.4RESULTSThe filled dots plotted in Fig.4represent the two-point cor-relation function of the ELAIS-S1galaxies computed us-ing the LS estimator.The errorbars,evaluated from the 30ELAIS-S1mock catalogs,are the same shown in Fig.3.Clearly,ξ(s )is well approximated by a power law out to separations of 10h −1Mpc.In the range 1−10h −1Mpc the best fit power law model ξ(s )=(s/s 0)−γ,has a correlation length of s 0=5.4±1.2h −1Mpc and a slope γ=1.45±0.25,both determined at the 90%confidence level.Including the correlation of galaxy pairs at separation s =0.6h −1Mpc,also shown in the figure,does not modify this result appre-ciably.Breaking down the sample by redshift does not change results significantly either.Indeed,in the local sample com-posed by 82objects at z <0.2ξ(s )is still well approxi-mated by a power law in the range 1−10h −1Mpc with best fit parameters s 0=5.4±1.6h −1Mpc and γ=1.6±0.4.These values agree with those found for the distant sample of 66objects at at 0.2 z <0.5for which we have found s 0=5.1±1.6h −1Mpc and γ=1.4±0.4,Finally,we have verified that evaluating errors from 100bootstrap realizations of the ELAIS-S1sample rather than from the mock catalogss does not change significantly the results as the correlation length only decreases by ∼10%and the slope becomes ∼4%flatter.5DISCUSSION AND CONCLUSIONSIn this work we have evaluated the redshift-space two point correlation function of mid-infrared selected galaxies in the deep (z 0.5)ELAIS-S1catalog.We found a significant,positive correlation signal at separations 10h −1Mpc,where the two point correlation function is well approx-imated by a power law model ξ(s )=(s/s 0)−γwith a correlation length of s 0=5.4±1.2h −1Mpc and a slope γ=1.45±0.25,with errorbars referring to a 90%confi-dence level.These results have been obtained using the LS estimator for ξ(s )and by evaluating the errors from a set of 30mock ELAIS-S1catalogs.These results are robust,in the sense that they do not change significantly when varying the method of estimating ξ(s )(see section 3.1)or when using different strategies to assess the errors (sections 3.2and 4).It is interesting to compare our results with those obtained from similar analysis of galaxy clustering in redshift-space.Table 1shows our result together with the corresponding results obtained from some of the ma-jor galaxy redshift surveys,characterized by their pass-band/wavelength of selection (column 2)and the redshift ranges they cover (column 3).It is worth stressing that de-viations of the two point correlation function from a pure power law shape are more serious in redshift-space than in real-space,making it difficult to compare results obtained from the analyses of different galaxy samples.To ensure a fair comparison,all best fit parameters listed in columns 4and 5of Table 1refer to ranges of separations where all measured ξ(s )are well approximated by a power law.These ranges turned out to be very close to that of [1−10]h −1Mpc considered in our analysis,although some of the parameters in the Table have been obtained by pushing the estimate of ξ(s )down to scale as small as 0.1h −1Mpc (the 2dFGRS case)or up to separations as large as 16.4h −1Mpc (as in the case of the LCRS sample).Our results are fully consistent with those obtained from the analysis of the PSC z survey (Hawkins et al.2001),that consists of ∼15,000IRAS galaxies selected at 60µm ,i.e.in a mid-infrared band similar to that of ELAIS galaxies.This sample is,however,much more local than ours and thus the agreement between the two results indicates that the clustering properties of mid-infrared selected objects do not evolve significantly between z =0and z =0.3.This conclu-sion is corroborated by the consistency found between the two measurements of ξ(s )performed in the local (z <0.2)and distant (0.2 z <0.5)ELAIS-S1subsamples.Unfortu-nately,the large uncertainties in our estimate of ξ(s ),that mainly result from the sparseness of the ELAIS-S1galaxy catalog,do not allow to set strong constraints on the clus-tering evolution.The lack of significant evolution in the ELAIS galaxy clustering has already been noticed by Gonzalez-Solares et al.(2004).In their analysis,that consisted in deprojecting the angular correlation function of ELAIS galaxies via Lim-ber equation,they have measured a real-space two point cor-relation function with a slope (γ=2.04±0.18)and a corre-lation length (r 0=4.3+0.4−0.7h−1Mpc)that are fully consistent with those measured in the PSC z catalog (γ=2.04±0.18and r 0=∼3.7h −1Mpc,Jing,B¨o rner &Suto (2002)).It is worth stressing that difference between our result and that of Gonzalez-Solares et al.(2004)originates from systematic redshift space distortions that affect our analysis and result in a shallower slope and a larger correlation length of the two point-correlation function.Focusing on the mid-infrared objects is of considerable interest since they trace the underlying mass distribution in the local universe.The consistency that we have found6V.D’Elia et al.Table1.Clustering of Different Galaxy Redshift Surveys:the Parameters of the Power Law ModelELAIS-S1115µm0.0-0.55.40±1.201.45±0.25PSC z260µm0.004-0.14.77±0.201.30±0.04CfA23B-band0.0-0.05∼7.5∼1.6ORS4B-band0.0-0.0277.60±1.201.60±0.10LCRS5R-band0.033-0.156.3±0.31.86±0.03SDSS5r⋆-band0.019-0.13∼8.0∼1.22dFGRS6b j-band0.01-0.206.82±0.281.57±0.071This analysis2Hawkins et al.(2001)3de Lapparent,Geller&Huchra(1988)4Hermit et al.(1996)5Tucker et al.(1997)6Zehavi et al.(2002)7Hawkins et al.(2003)Monthly Notices:L a T E X2εguide for authors7 Verde,L.et al.2002,MNRAS,335,432Wirth,G.D.et al.2004,AJ,127,3121Zehavi,I.et al.2002,ApJ,571,172。
（宇宙）高中英语阅读短文《发现黑洞》及答案北京时间2019年4月10日21时，天文学家召开全球新闻发布会，宣布首次直接拍摄到黑洞的照片。
阅读题目，回答问题文本选自：The Guardian（卫报）Recently,scientists produced the first real image of a black hole,shining a light onone of the universe’s great mysteries,in a galaxy called Messier87.The image is not a photograph but an image created by the Event Horizon Telescope(EHT)ing a network of eight ground-based telescopes across the world,the EHT collected data to produce the image.The black hole itself is unseeable,as it’s impossible for light to escape from it;what we can see is its even thorizon.The EHT was also observing a black hole located at the centre of the Milky Way, but was unable to produce an image.While Messier87is furtheraway,it was easier to observe,due to its larger size.The golden ring is the event horizon,the moment an object approaching a black hole reaches a point of no return,unable to escape its gravitational pull.Objects that pass into the event horizon are thought to go through spaghettification（意大利面条化）,a process,first described by Stephen Hawking,in which they will be stretchedout like a piece of pasta by gravitational forces.Heino Falcke,professor of radio astronomy and astroparticle physics at Radboud University in Nijmegen,and chair of the EHT science council, says the image shows asilhouette（剪影）of the hole against the surrounding glow of the event horizon,all of the matter being pulled into the hole.At the centre of the black hole is a gravitational singularity, where all matter is crushed into an infinitely small space.The black hole lies55m light years away from us.It is around100bn km wide,larger than the entire solar system and6.5bn times the mass of our sun.Through creating an image of a black hole,something previously thought to be impossible,the EHT project has made a break through in the understanding ofblack holes,whose existence has long been difficult to prove.The image will help physicists to better understand how black holes work and images of the event horizon are particularly important for testing the theory of general relativity.1.What’s the text mainly about?A.The image of a black hole.B.The photo created by the EHT.C.The event horizon of the black hole.D.The introduction of the EHT project.2.How does EHT collect data?A.By producing the image of a black hole.0B.By studying the golden ring in the photo.C.By observing the center of the Milky Way.D.By using a network of eight ground-based telescopes.3.What do we know about the black hole fromthe text?A.Its image shows a silhouette of the event horizon.B.There is a possibility that light can escape from it.C.All matter is crushed into small space at its centre.D.Objects will be stretched out outside the event horizon.4.What does the last paragraph mainly present?A.Creating an image of a black hole is thought to be impossible.B.It’sstill hard for physicists to prove the existence of the black hole.C.The image will help physicists to test the theory of general relativity.D.The image of a black hole created by EHT project is highly significant.参考答案：ADCD生词及长难句1.Galaxy n.星系the galaxy银河系2.event horizon视界德国天文学家卡尔·史瓦西计算出一个巨大天体可扭曲周围空间，以至于连光都无法逃脱，这个特定的半径就是我们所致的史瓦西半径，也可以称之为“视界”。
让我们回到印第安纳波利斯And we're back at the final stretch of500英里大赛的角逐现场the Indianapolis 500.世界三大汽车赛事之一简称印第500盖·加涅正在逐步超越Guy Gagnéis gaining on the pack.这位年轻的法裔加拿大人The young French Canadian在印第赛车场的处子秀is making quite an impression就来了个惊艳登场in his debut here at the Motor Speedway.看了这么多年赛车In all my years of racing,我还从未见过如此具有天赋的赛车手I've never seen a driver with this much raw talent.但这是谁But what's this?突然杀出一匹黑马紧逼着加涅Out of nowhere, a dark horse is challenging Gagné.他极速猛冲He's gaining on the pack.抢入了直道And down the front stretch.升到第四第三现在冲到了第二Moving into fourth position... third... Now, second!驶到外圈冲向终点Going to the outside as they cross the bricks!看来最终的冠军是特搏And it looks like the winner is Turbo!太精彩了难以置信Amazing! Unbelievable!即时重放再播一次慢动作Instant replay. Again, in super slo-mo.欢迎回来赛车迷们Welcome back, race fans.我们将要采访的是尹第新秀盖·加涅We're here with Indy's brightest new star, Guy Gagné. 告诉大家盖Tell us, Guy,你为什么会成为一名赛车手what inspired you to become a race driver?你知道的丹You know, Dan,总会有那么一件事让你欢欣鼓舞everybody's got that one thing that makes them happy.对我来说那就是风驰电掣的速度And for me, it's terrifying, terrifying blazing speed.盖Guy!-请一个一个来-西奥- One at a time, please. - Theo!好请后面那位帅哥先说Yes, the handsome fellow in the back.你在做什么What are you doing?老样子全神贯注跑比赛What I've always done. Stay focused, try to run my race.赛车手都这样下一个问题That's all any driver can do. Next question.拜托你能不能回去睡觉Can you please go to sleep?我们明天还得工作呢We've got work tomorrow.睡觉有没有搞错Sleep? Are you kidding me?赢了这么重要的比赛我还激动着呢It takes hours to come down after a big race like this. 是当然好吧Yeah, I bet. Okay.他们是我冲刺的动力They are the fuel that keeps me running!盖当你初出茅庐的时候Guy, when you were just a rookie starting out in the Indy Lights, 是否梦想过有朝一日能登上冠军奖台did you ever dream that you'd be standing here today?当然父亲总是教导我Well, as my dear father always told me,没有遥不可及的梦想小人物也有"No dream is too big, and no dreamer-逐梦的权利-逐梦的权利- "Too small." - Too small.快去睡觉Sleep!起跑线集中精力全神贯注Head in the game. Head in the game.太棒了17分钟新纪录Yes! Seventeen minutes! That's a new record!西奥Theo!早上好Good morning.出发伙计们别落下Let's go, people! Pick it up!特搏准备超车Turbo, ready to make his move.你看到了吗她竟然挡我Did you see that? She cut me off!赛车欢乐多啊The joys of racing.怎么会有人不去欣赏How could anyone not see the appeal of watching a bunch of cars,一堆车绕好几个小时的圈圈呢drive around in circles for hours on end?左转再左转又左转Left turn! Left turn! Left turn!你的愚昧无知真让人悲哀Your ignorance saddens me to no end.左转我还要做些什么呢Left turn! "What do I do here?对了还是左转Oh, no, wait a minute. Left turn!"早上好切特Morning, Chet!最近怎么样莎莉How's it going, Sally?-早上好切特-早上好菲尔- Morning, Chet. - Morning, Phil.真是不幸Well, that's a shame.美好的菜园工作周又开始了And so begins another wonderful work week at the plant.伙计们今天要收获很多西红柿All right, people, we got a lot of tomatoes to harvest today.我们要采摘分类还要吃掉它们We got to pick them, we got to sort them, we got to eat them.但最重要的是我们要保证But most importantly, we got to be安全Safe.没错就爱听这句Yes! Music to my ears.快看她Look at her.曲线优美Nice curves.你这个秀色可餐的女神You are one giant, juicy temptress.大红美Big Red.指日可待Any day now.何年何月Any day now.熟过头的Overripe!熟过头的Overripe!熟过头的Overripe!不Oh, no.来吧Here we go.再试试Bring it on.这次休想Not this time.赛手们已于起跑线准备就绪And the cars are at the starting line.加涅排在首发位置Gagné's in the top pole position,驾驶印有一号标识的烂熟西红柿driving his trademark number one overripe tomato.他旁边的是跃跃欲试的新人特搏Next to him is that feisty young upstart, Turbo.先生们启动引擎Gentlemen, start your engines.加涅领先拐过第一个弯道Gagnérolls into the lead around the first turn特搏紧随其后驶向直道with Turbo hot on his tail into the straightaway.他又开始意淫了Hey, there he goes again.最后冲刺观众们沸腾了And down the homestretch, the crowd goes wild!加油特搏Go, Turbo!他们难分轩轾They're neck and neck!加涅特搏特搏加涅Gagné, Turbo! Turbo, Gagné!-看来冠军是... -特搏特搏特搏- And it looks like the winner is... - Turbo! Turbo! Turbo!好险So close!几乎同时越线It's a photo finish!熟过头的Overripe!好了好了别闹了All right, all right, knock it off.劝劝你弟弟切特要不我来说Talk to your brother, Chet. Or I will.我会去的卡尔I'm on it, Carl.下不为例This will not happen again.以前也这么说Heard that before.好吧Okay.开饭喽That's lunch!#p#分页标题#e#你这是自作自受知道吗You do this to yourself, you know.瞧瞧你I mean, look at you.他们怎么可能不取笑你How could they not make fun of you?你本身就是个笑话It's like you're almost forcing them.如果你不去想那些赛车什么的If you'd just quit it with the speed stuff...我做不到I can't help it.那是我的天性It's in me.不才不是什么天性No. It is not "In" You.谁说的Says who?大自然我们的母亲Nature. Mother Nature.听说过她吧Maybe you've heard of her?她赋予我们的天性不是速度西奥We all have our limitations, Theo.你就是个行动迟缓的悲剧And the sooner you accept the dull,愈早接受这个事实miserable reality of your existence,才会变得更加幸福the happier you'll be.你还真是会说话啊Wow. Aren't you just a little ray of sunshine?当心蜗牛杀手两点钟方向Heads up! Shell crusher, two o'clock!大家注意按照预演的做All right, people, you know the drill.缩壳快滚Tuck and roll!缩不进去我缩不进去Can't tuck. I can't tuck!西奥缩壳快滚Theo, tuck and roll!以前就说过我就不缩壳快滚We've been over this. I don't tuck and roll.你背着壳是有原因的缩进去You have a shell for a reason. Use it.缩你的You use it.拜托他都没看这边I mean, come on, he's not even looking this way.喂喝果汁那个好车啊Hey, Juice Box, nice tricycle!听见我说什么了吗You see what I'm saying?好了躲得好All right, good hustle.大家都躲得很好Good hustle, everybody!除了你Almost everybody.下班时间Quitting time!晚安吉姆晚安莎莉Good night, Jim! Night, Sally!晚安史蒂夫我不知道你叫什么Night, Steve! I don't know your name.我先走了再见I'm out of here! Bye!您现在收看的是《追风竞速》栏目You're watching Fast!由激动饮料赞助播出Sponsored by Adrenalode!激动在犹他和南达科塔州暂不合法Adrenalode, not legal in Utah and South Dakota.请不要在24小时内Do not exceed more than连续饮用超过两灌激动two cans of Adrenalode in a 24-hour period.请将激动远离火水和沙土Do not expose Adrenalode to flame, or to water, or to sand. 没错Yes!口感爽爆了That tastes awesome.欢迎回到"直击印第安纳波利斯"专题报道Welcome back to The Road to Indianapolis.我身边的是印第五连冠I'm here with five-time Indy champ,传奇车手盖·加涅the legendary Guy Gagné!我爱你盖I love you, Guy!告诉大家盖对那些可能Tell us, Guy, do you have any advice在家中电视机前的未来赛车手for the future racers out there你有什么建议呢who might be watching at home right now?天啊说我呢说我呢Oh, my gosh. That's me, that's me.每一场角逐Well, there comes a time in every race都会有这么个关键瞬间when a driver is forced to make that one,车手不得不做出抉择key, split-second decision.是减速退守还是勇往直前Fall behind, or push ahead.勇往直前Push ahead!是铤而走险放手一搏To take a chance and risk it all,还是稳扎稳打甘于失败or play it safe and suffer defeat.放手一搏盖Risk it all, Guy!但真正使冠军区别于普通车手的But what really separates the racers from the champions 快说Yes!唯一一点that one thing that使你卓尔不群的separates the ordinary from the extraordinary是什么What is it?那就是... That one thing is...不No!不别这样No, you didn't!不不不不不No! No! No! No! No!快回来电视Come back to me, TV!-只有做到... -管用了- Only you have your finger on the... - It's working!-早上好鲍勃-早上好莎莉- Morning, Bob. - Morning, Sally.早上好史蒂夫Morning, Steve.早... Morning...其实这是好事You know, this is good.是啊好事Yes, this is good.我觉得这是个重大进展I daresay we've had a breakthrough, here.电视没了你终于可以走出车库With that TV gone, you can finally get out of that garage 忘掉那些关于赛车的鬼话and put all that racing nonsense behind you.然后呢And do what?享受你的真实生活啊Start living your life.我有自己的生活吗I have a life?大红美Big Red?大红美Big Red!缩不进去我缩不进去I can't tuck. I can't tuck!-太棒了-终于熟了- Yes! - Finally!太好了我们可以一饱口福All right, let's chow down!大家慢着Hit the brakes, people.今天是剪草日It's Gardener Day.你们就这样放弃了You're quitting? Just like that?撑死胆大的饿死胆小的Hey, nothing ventured, nothing gained.你们这样是不对的That's a bad thing.每一场角逐"There comes a time in every race都会有这么个关键瞬间when a driver is forced to make that one,车手不得不做出抉择key, split-second decision."他说什么What did he just say?是铤而走险放手一搏"Take a chance and risk it all,还是稳扎稳打甘于失败or play it safe and suffer defeat."好了别疯言疯语了西奥Okay, enough with the crazy talk, Theo.离草坪远点回去工作Just step away from the grass and get back to work.西奥Theo!赛手们已于起跑线准备就绪And the cars are at the starting line.先生们启动引擎Gentlemen, start your engines.特搏凶残割草机又一次特搏处于领先And once again, it's Turbo out front.没有遥不可及的梦想No dream is too big.驶入快车道就在终点线In the high lane! At the stripe!看来冠军是And it looks like the winner is...缩壳快滚西奥缩壳快滚Tuck and roll, Theo! Tuck and roll!#p#分页标题#e#不No!你疯了吗Are you insane?你差点就没命了You could've gotten yourself killed!西奥你到底在想什么Theo, what were you thinking?我以为我能冲过去I thought I could get there.你什么时候才能清醒些When are you gonna wake up?许个愿I wish...我希望我能I wish I was...好险That was close.不Oh, no.太棒了Yeah!不不加油加速No, no, no! Come on! Faster!氧化亚氮不不不No, no, no!又怎么了What happened?干什么滚开Hey, hey, hey! Get out of here!我没死没死Not dead! Not dead!真是熏死我了It reeks in here.简直就像裹着一只臭袜子It's like wearing a hat made out of feet.总算到家了Home.很好All right.我没事I'm okay.有点不对劲That's peculiar.我这是怎么了Okay, what's happening to me?怎么回事是我身上的What? That's me!拜托别响了Come on! Stop it!安静安静Quiet, quiet!别响了别响了别响了Stop it! Stop it! Stop it!欢迎大家出席月度安全大会Welcome, everyone, to this monthly safety meeting.杰里就这么走了Well, there goes Jerry.现在有请切特讲话I'm going to hand things over to Chet, now,他要申明一些重要的安全新措施who has some important new policies to go over.非常感谢卡尔大家下午好Thank you very much, Carl. Good afternoon, everyone.很高兴为大家解读新"错"施I'm happy to "Poli-see" You all here today.好吧我先宣布几条激动人心的消息Okay. I would like to begin with some very exciting news.最新数据已经统计出来了The latest figures are in.意外砸伤事件下降了十五个百分点Accidental smashes were down 15 percent.做得好大家伙Well done, team.着名说唱乐队RUN-DMC的《棘手》摇滚的节奏很棘手It's tricky to rock a rhyme配合正确的时间正确的打奏To rock a rhyme that's right on time非常棘手十分棘手相当棘手It's tricky tricky tricky tricky tricky tricky你现在收听的是调频98.6动感嘻哈Yo, yo! You're listening to 98.6 where hip-hop... beats. 乐坛传奇人物汤姆·琼斯的《风流绅士》总算消停了Finally.怎么搞的What in the...救命啊Help!停下停下停下Stop! Stop, stop!妈妈Mom!棒极了Yeah!不Oh, no!为了准备防范乌鸦宣传周And so, in preparation for Crow Awareness Week,我宣布I'd just like to say...缩壳快滚Tuck and roll!不我没开玩笑缩壳快滚No, I'm not kidding! Tuck and roll!小心Look out!我承认Granted, yes,我承认存货遭到了一点点的破坏I admit that there's been a wee bit of damage to inventory, here,但请你们听我解释but if you'd just let me explain...开除You're fired!息怒卡尔再给他一次机会吧Whoa, okay, Carl, if you just give him one more chance,我保证他再也不... I promise that this will never, ever...没听懂是不你们被开除了You don't understand. You're fired.你们是复数你俩"You," Plural. Youse.你和他两个都是Y'all. Both of you!切特我很抱歉Chet. I'm so sorry.请相信我我不是故意的You have to believe me, I didn't mean for this to...我这一生All my life.我这一生都在护着你罩着你All my life, I've defended you, covered for you,和你坐一条船还替你背黑锅stood up for you, apologized for you,结果落得如此下场and this is what I get in return.被你的破船一起拖下水Dragged down with you on your sinking ship.还附送漂亮又舒适的船上躺椅西奥 A nice, comfy deck chair on the S.S. Theo!真有你的船长Aye-aye, Captain!我真的很抱歉I'm really sorry.你脑子有毛病吗What is wrong with you?我不知道我只记得那天晚上I don't know. All I know is, the other night,我站在101公路天桥上突然阴风四起I'm standing above the 101, and all of a sudden... 没叫你答听不出那是个反问句吗It was a rhetorical question!切特Chet!救命怎么到处都在转动Help! The world is moving!借过Coming through!这一定是在做梦我随时都会醒来的Okay, I'm gonna wake up any minute now.醒醒快醒醒Wake up! Wake up!墨西哥玉米卷零售切特Chet?别激动伙计们不是来真的吧Easy now, fellas. You really don't wanna do this.切特Chet!我死了吗我在天堂吗Am I dead? Is this heaven?天堂应该... I pictured it更干净才对cleaner.快点起来Come on, get up.西奥你也被乌鸦吃掉了Theo. The crows got you, too.什么没有切特What? No, Chet,不是乌鸦而是it wasn't the crows. It was...看看这地方Look at this place.-碎玻璃锈铁钉-深呼吸- Broken glass, rusty nails. - Breathe.-破盐罐子-别紧张- Discarded salt packets! - A few, yeah.这里简直是雷区It's like a minefield out here.不要我得了破伤风破伤风啊Oh, no. I've got tetanus. I've got tetanus.牙关都闭紧了My jaw is locking up.破伤风特征性表现切特冷静点没必要慌张Chet, will you calm down? There is no reason to panic. 一切都在控制中Everything's gonna be just fine.看看是谁来了晚上好小家伙们Well, well, well. Buenas noches, little amigos. 今天真是好运气This must be my lucky day.喂是我提托Hola. It's Tito.告诉大家我会带来的Hey, tell everyone I'm bringing it.哥俩好卷饼店这是什么地方What is this place?哈哈哈Well, well, well.你们最好还是报警吧Somebody better call the cops,#p#分页标题#e#因为我可要大杀四方啦because I'm about to make a killing.大杀什么Killing?他又带来了什么货色What'd he drag in this time?鞭索一定会生吞活剥他们Whiplash is going to eat them up.这会是一场屠杀It's gonna be a slaughter.板上钉俎上肉Mm-hmm, dead meat.我们要死了我们要挂了We're gonna die. We're gonna die.快点动作利索点Come on, come on. Now, hurry up.你离家有点远了吧乡下蜗牛 A little far from home aren't you, garden snail? 我看有人吓得尿裤子了Hey, I think we got a crier here.快点开始吧Let's do this!我赢定了要的就是这感觉I got this one! Oh, I got this one!来吧看我发威Come on! This is me!逃跑时间西奥Time to go, Theo.各就各位Ready预备Set跑Go!看它完了Look. He dead.卷饼哥找了只傻蜗牛Taco Man found dead snail.那是啥What?快闪Run!我的神啊Santa Maria!你刚才说你叫什么来着What did you say your name was again?我的大名是特搏My name is Turbo.我真想改个名字I wish I could rename myself.你在哪儿找到他的Where did you find him?你怎么做到的How did he do that?你从哪儿来的Where did you come from?喂你到底怎么做到的Hey, how'd you do that?西奥借一步说话Theo. A word, please.那个刚才真是Okay, that was帅呆了是吧Amazing, right?我还会更炫的招数看这个If you think that's something, check this out.把它关掉Turn it off!错打了远光灯抱歉Sorry. High beams. Sorry.咦还有这玩意儿That's a new one.没事的放心西奥你要挺住It's okay, it's okay, Theo. Just hang in there.等我们一到家就把你治好As soon as we get home, we're gonna get you fixed.什么我才不需要治疗What? I don't need to be fixed.我又没出什么问题切特There's nothing wrong with me, Chet.没什么问题你已经Nothing wrong with you? Well, you're变成个怪物了You're a freak of nature.我知道那不是很棒吗I know, I know! Isn't it great?西奥Theo!不瞒你说我更喜欢特搏这个名字You know what? I prefer "Turbo."意为涡轮增压机不管你是从哪个实验室逃出来的I don't know what crazy lab you escaped from你可帅呆了小伙伴酷毙了but you're amazing, Little Amigo. Amazing!提托Tito!稍等一下One second, please.看到那商标了吗写的什么Do you see that sign? What does it say?安杰洛Angelo写的是哥俩好卷饼It says, "Dos Bros Tacos."哥俩好提托不是老光棍卷饼"Dos" Bros, Tito. Not "Uno" Bro.你应该在门口兜售卷饼You're supposed to be out there, selling tacos,而不是搞什么蜗牛赛跑not racing snails.我知道但是这小家伙有点特别I know, but this little guy is something special.我告诉你安杰洛I'm telling you, Angelo,客人们会把这里挤得水泄不通the customers are gonna be lining up around the block.我已经预见了I can see it already.蜗牛赛跑趣味多美味卷饼不可少"Come for the snail racing, stay for the chimichangas." 你快点给我醒醒Get your head out of the clouds,提托痴人说梦到此为止Tito. It's enough with your crazy schemes.不要你是个卷饼天才安杰洛No! You're a taco genius, Angelo.而我的使命就是让你的卷饼举世闻名And it is my mission in life to share your gift with the world.没错你要做的第一件事Great. Then first thing in the morning,就是爬进卡车给我卖卷饼get in that truck and go sell some tacos.提托Tito.你确定吃饱了吗累了没You sure you had enough to eat? Are you tired?看这我给你铺好了床Here, I made up your bed.今晚可能有点凉Now, it might get a little chilly tonight.我给你暖了暖被褥So, I warmed up your blanket.好了舒服又温馨There you go. All comfy and cozy.祝你好梦小家伙明天早上见Sweet dreams, Little Amigo. I'll see you in the morning.他刚才是亲亲晚安了吗Did he really just kiss you goodnight?没错嫉妒吗He did. Jealous?问一下你怎么得到超速度的Question. What gives with the super-speed?喂你是机器人吗Hey, hey, you a robot?你有放射性吗老兄Are you radioactive, homie?会传染吗Is it contagious?离这孩子远点Give the kid some space.我是鞭索这是我的团队I'm Whiplash. And this here is my crew.我是滑痕I'm Skidmark!真爽Ah, yeah!我是烈火咝咝咝咝And I'm Burn. Sizzle, sizzle, uh-uh.我叫漂移是这里定基调的懂吗The name is Smoove Move. I set the tone around here, you dig?看好了就是现在Now check this. Right about now,我速度之快I'm moving so fast,让整个世界都陷入慢动作宝贝儿the whole world's going in slow motion, baby.下一秒隆重出场的是Here one second, gone the next.人称白色幻影的我They call me the White Shadow!因为太快你只能看到我的影子Because I'm so fast, all you see is my shadow.我不明白I don't get it.身形轻盈快如魅影I'm fast, like a shadow!但是你的影子明显和快没什么关系Yeah, but shadows, they're not inherently fast.白色幻影White Shadow.还是能看到你I can still see you.听着乡下蜗牛Listen, garden snail,很明显你有两把刷子you clearly got the skills to pay the bills.如果蜗牛也有刷子你的挺大If snails had to pay bills, that is.你有两把大刷子You would be able to pay them.没错刷子Yeah, bills.刷子挺好用孩子Paid in full, son.我来这是邀请你加入我的团队So, I'm here to invite you to join our crew.加入你的团队Join your crew?#p#分页标题#e#我的话很滑稽吗Did I say something humorous?不好意思只是你们大家你懂的I'm sorry. It's just that you guys are, you know,有点慢...吞吞的kind of slow-ish.过分一点都不给面子Really? To our faces?西奥你在干什么Theo, what are you doing?我当你放了个屁虽然我闻到了异味Now, I'm gonna pretend I didn't hear what I clearly just heard.闻到什么我什么都没闻到Heard what? I didn't hear anything.大家还是可以讲道理的是吧西奥Nothing out of order, did you, Theo?我是认真的I meant what I said.你最好别给我吹破牛皮Then you better put your money where your mouth is.蜗牛可吹不动牛的皮Snails don't have money.不然我们都会用刷子了是吧Otherwise, we'd be able to pay the bills. Remember?你打嘴仗还装什么有深度Your trash talk is needlessly complicated.是吗还是你的刷子烂到毛都掉光了Is it? Or is it that your unpaid bills are overdue?说够了吧看看你有什么能耐Enough talk. It's time for action.规则很简单第一个到达流星的It's simple. First one to the top of that shooting star星光广场就是赢家wins.就凭你们要上那里吗很好You guys? Way up there, huh? Awesome.不如我用本年历来帮你计时吧Let me get my calendar so I can time you.挺会说笑菜鸟You got jokes, rookie?尽管笑吧乡巴佬Laugh it up, garden snail.各就各位On your mark预备Get yourself set见识一下白色幻影的厉害Prepare to be White Shadowed!借个道Coming through!他们都疯了Those guys are crazy!他们真有意思Those guys are awesome.那个谁上来玩玩吧Hey, player! The party up here!我要怎么上去How do I get up there?再见Later!也借个道Coming through!谁才是慢吞吞的乡下蜗牛Who's "Slow-ish" Now, garden snail?改变就在今天Today, everything changes!史上最快蜗牛尽在哥俩好卷饼店提托你在做什么Tito, what are you doing?我在策划一个"卷新" Planning a "Taco-volution"!这是我想出来的妙点子It's a little concept that I came up with.当你把那两个词语组合When you combine the words"卷饼"和"创新" 我明白的"Taco" And "Revolution." I get it.但是那对卖卷饼有什么帮助吗But how is that supposed to help us sell tacos?耐心点老兄罗马不是一天建成的Patience, bro. Taco-volutions don't happen in a day. 下一站是洛城大河And next up on our tour is the L.A. River.它赫赫有名因为... Famous for its appearance...走走快走Get! Get out!对不起帕斯能递上来给我吗Sorry, Paz. Can you throw that up here?汽配店看我追上你看我追到你Coming to getcha! I'm coming to getcha!欢乐谷模型店再会Bye.你好Hey!欢乐谷模型店我是鲍比为您效劳Valley Hobby, this is Bobby, how can I help you?你拨错电话了没事No, you got the wrong number. Yeah, okay.看我不追上你That's what I'm talking about!想来个杰克逊五人组式美甲吗You want Jackson Five on your feet?每个脚趾都有One Jackson per toe.天王在故乡印第安纳州的家庭乐队好啊你随意发挥吧Sure, knock yourself out.完美无缺Can't get no better.好吧你的计划是什么Okay. So, what's your plan?和一群疯子蜗牛Stay here in this rundown strip mall?还有一个想用你推销墨西哥小吃的人With a bunch of lunatic snails,在这排破店铺子里混吃等死吗and a nutso taco man who is using you to sell Mexican food? 要是那样奶奶个熊把我弄死算了Because if that's your plan, then whoopty-skippy-do, sign me up!我耳朵根发痒你们是在谈论我吗My ears are burning. I hope you're not talking about me.你俩看起来关系不一般小家伙You two seem to have a special connection, Little Amigo, 这个看起来是小家伙朋友的蜗牛and Snail Who Seems To Be Friends With Little Amigo.她是你母亲吗Is this your mother?还是你姐姐Your sister?不用说了肯定是你女朋友Say no more. It's your girlfriend.她是个可人儿She's a cutie.女汉子Women.我得承认I have to admit,我真希望"卷新"现在就可以开始I was kind of hoping the taco-volution would've started by now.没道理啊It doesn't make sense.我的头脑加上你的速度With my brains and your speed,我们应该大有作为才对是吧we should be destined for greatness, right?我们得大张旗鼓一下小家伙We need to think big, Little Amigo.我是说广告脱口秀和展览会什么的I'm talking commercials, talk shows, county fairs.跳蚤市场不对Flea markets. No,是农贸市场错了是超市farmers' markets. No, supermarkets.总之是各种市就对了We'll cover all the markets.成人礼坚信礼毕业典礼Quinceanera, confirmations, graduations.印第500大奖赛The Indy 500.我想到了我们应该有自己的肥皂剧I got it. We can have our very own telenovela!印第500大奖赛什么才不What? No.就是这个切特This is it, Chet.我知道我们来这是有原因的I knew we ended up here for a reason.你能不能慢一点Will you just slow down for a second?慢开玩笑吗我的字典里没有慢Slow down? Are you kidding? I'm never going slow again!西奥停下Theo, stop.你要表达什么What are you trying to say?我要让他参加大奖赛I wanna enter him in the Indy 500.大奖赛你在胡说什么The Indy 500? What are you talking about?他在说什么What is he talking about?听着也许这听起来有点疯狂Now, look, I know it may sound a little crazy不不不提托这可不疯狂No, no, no, Tito, that doesn't sound crazy.哥俩好卷饼寿司那有点疯狂Dos Bros Tacos and Sushi. That was crazy.怎么会大家都爱寿司What? People love sushi.哥俩好卷饼亲猴乐园那也有点疯狂Dos Bros Tacos and Monkey Petting Zoo. That was crazy.#p#分页标题#e#孩子们很有爱大人们可太刻薄了The babies were cute. The adults were just so mean.卷饼超人和他的小弟油条人Taco Man and his sidekick, the Churro.那是真他娘的疯狂That was off-the-hook crazy!是疯狂到正点Crazy awesome.但这个计划提托But this, Tito?疯狂都只配给它提鞋This is in a category all by itself.安杰洛拜托了Angelo, please.我拜托你切特听我一句劝Come on, Chet. Just hear me out.西奥蜗牛不能参加汽车大奖赛Theo, a snail cannot race in a competition meant for cars. 规矩就是规矩There are rules.事实上我做了很多调查Actually, I've been doing a lot of research,没有规则禁止蜗牛参加比赛and there's nothing in the rules that says a snail can't enter the race.规则也没说海绵不可以参赛There's nothing that says this sponge can't enter the race either,但是那永远不可能发生but that doesn't mean it's ever gonna happen.几百万人都看这比赛Millions of people watch that race.我们会让小镇名扬天下的老兄This could put us on the map, bro.-有人可要忙工作了-拜托安杰洛- Trying to work, here. - Come on, Angelo.我们只需要两万美金的参赛费All we have to do is raise the $20,000 registration fee.什么What?-我在想只要卖了卡车-卖卡车- I figured, once we sell the truck - Sell the...你听听自己在说什么提托Are you even listening to yourself, Tito?你要把我们毕生积蓄花在一只蜗牛身上You want to invest our entire life savings in a snail!我告诉你这只蜗牛背负使命找到我们I'm telling you, this snail crawled into our lives for a reason.我觉得他就是我们的幸运星I think he could be our little shooting star.听到了吗切特那人相信我Did you hear that, Chet? This guy believes in me.那人和你一样都疯了That guy is as crazy as you are.你永远不会被允许参赛They'll never let you into that race.就算你能你连一圈都熬不过去And even if they did, you wouldn't survive one lap.可是安杰洛听我说Yeah, but Angelo, listen...-提托-西奥- Tito! - Theo!不是所有梦想都可以实现Not every dream is meant to come true.他说得没错Yeah, what he said.蜗牛参加印第500 真有你的 A snail in the Indy 500.下一步你又要做什么What will you think of next?别担心小家伙Don't worry, Little Amigo.我们总会筹到参赛费的We'll get that entrance fee somehow.有人觉得两万美金是一大笔钱Now, I know some people may say $20,000 sounds like a lot of money.那就是一大笔钱It is a lot of money.也有人说我肯定疯了And I know some people may say I'm crazy.但是But I say,当一只蜗牛以300公里的时速when a snail crawls into your life闯进你的生活at 200 miles an hour,要是不抓住这千载难逢的机会then you'd have to be crazy not to grab onto that shell,那才是真疯了and take a ride of a lifetime.如果你还没有被说服Now, in case you're still not convinced看看我精心设计的热血海报吧Boom! Check out my well-designed endorsement poster.你想说什么提托What's your point, Tito?我想说我们有机会将生活变得更美好My point is, we got a chance to change our lives for the better.把星光广场变得和梦想中一样美好To make Starlight Plaza the great place we all know it could be.那么现在Now, come on.准备好要赞助下一届大奖赛冠军了吗Who's ready to sponsor the next Indy 500 champion?抱歉提托我还有活儿要干Sorry, Tito, but I've got work to do.不你很闲你们都闲爆了No, you don't. None of you do.我真不明白那海报多牛逼啊I don't get it. That poster was awesome.干得不错你尽力了该回家了西奥Well, good try, you did your best. Time to go home, Theo.我们一定要去印第安纳波利斯切特We're going to Indianapolis, Chet.你就张着那小胖脸看好吧Don't you worry your chubby little face about that.准备好队员们All right, team.蜗动起来Snail up!下一站是洛城大河And next up on our tour is the L.A. River.旅游观光它因为经常在电影中出现而闻名Famous for its appearance in such movies as...白色幻影来也You've just been White Shadowed!。
arXiv:astro-ph/0404446v1 22 Apr 2004TheInterplayamongBlackHoles,StarsandISMinGalacticNucleiProceedingsIAUSymposiumNo.222,2004Th.StorchiBergmann,L.C.Ho&H.R.Schmitt,eds.c2004InternationalAstronomicalUnionDOI:00.0000/X000000000000000X
Large–andSmall–ScaleFeedbackinthe
StarburstCentersofGalaxies
DanielaCalzetti11SpaceTelescopeScienceInstitute,Baltimore,MD21218,USAemail:calzetti@stsci.edu
Abstract.TheinterplaybetweenstellarpopulationsandgasinlocalstarburstgalaxiesisanalyzedusingimagesfromtheHubbleSpaceTelescopetomaptheagesoftheyoungstellarcomponentsandtoisolatethecontributionofshocksonspatialscalesrangingfromafewtensofpcto∼1kpc.Theshockedgasrepresentsasmallfractionofthetotalionizedgasintheseobjects,yetitcanhaveprofoundeffectsonthelong–termevolutionofthestarburst,whichmayincludethetriggeringofnewstarformation.2D.Calzetti
largerscales,superwindsarebestinvestigatedonkpcscales,whileprobingtheinfluenceofglobalparametersinvolvesscalesoftensofkpc(galacticsizes)toMpc(interactions).Evenfortheclosestgalaxies,thesmall–to–intermediatescalesrelevantfortheinterac-tionfeedback–ISMareaccessibleonlyviahighangularresolutionobservations(e.g.,withtheHubbleSpaceTelescope),as10pc=0.4′′foragalaxyat5Mpcdistance.ThestudyreviewedhereinvolvesfourlocalstarburstgalaxiesobservedwiththeWideFieldPlanetaryCamera2ontheHST.Becauseoftheirintense-to-extremestarfor-mationrates,starburstgalaxiesarethesiteswherestellarfeedbackcanhaveitsmostdramaticinfluenceonthestructureandevolutionoftheISM(andsurroundingIGM;Heckman,Armus&Miley1990),andare,therefore,optimallaboratoriestoinvestigatemechanicalfeedback.Thefourgalaxiesinthepresentstudycoverarangeinluminosity,metallicity,starformationrate,andenvironment,buttheyareallcloserthan5Mpc(Ta-ble1).Thisinvestigationattemptsataddressingtheissueofthecouplingfeedback–ISM,anditsrelationtothedurationofthestarformingevent.Theproblemistackledfromtwofronts:stellarpopulationsandISMconditions.Theagesoftheyoung(300Myr)stellarclustersareusedtosetaminimumvaluetothedurationofthecurrentstarburstevent,whilemeasurementsoftheshockedgasprovideaconstraintonthefractionofstar-burstmechanicaloutputthatisrecoveredintheISMwithinasmalldistance(1kpc)ofthesiteofstarformation.
2.ChartingtheYoungStellarPopulationsinStarburstsThestarclusterpopulationsandthespatialdistributionsoftheirageswithinthestarburstsiteswereinvestigatedforthreeofthegalaxieslistedinTable1,NGC3077,NGC5236,andNGC5253(Harrisetal.2001,Harrisetal.2004).ForNGC5253,thedif-fusestarburstpopulationhadpreviouslybeenage-dated(Calzettietal.1997,Tremontietal.2001),which,combinedwiththemorerecentstudyofitsclusterpopulation,yieldsacompletepictureoftherecentstarformationhistoryinthisgalaxy.ImagesofthegalaxiesintheHST/WFPC2mediumandbroadfiltersUV,V,I,andintheHαandHβlineemissionprovideenoughangularresolutiontoidentifyclusters,andenoughcolorinformationtoage-datethem.Inparticular,twoage–sensitivediag-nostics,thecolor–colordiagramUV−VversusV−IandtheequivalentwidthofHα,werecombinedtoconstrainthemostlikelyageforeachstellarclusterand,assumingaSalpeterIMF,toassignamass(Figure1;Harrisetal.2001,Harrisetal.2004).Hα/HβTheInterplayamongBlackHoles,StarsandISMinGalacticNuclei3ratiomapswereusedtocorrectphotometryandfluxesfortheeffectsofdustredden-ing(Calzetti,Kinney&Storchi–Bergmann1994).Theclusterageswerethenre-mappedontothegalaxyimagestoderivethehistoryoftheclusterformationineachstarburst.Thetwodwarfgalaxies,NGC3077andNGC5253,showtime–extendedstarformation,spanningthelast100–300Myr,andavery‘chaotic’spatialdistributionoftheclusterages.Thissimilaritybetweenthetwogalaxiesiscounterbalancedbystrikingdifferences.InNGC3077,therearestarclustersasoldas300Myr,whileinNGC5253theoldestclustersunambiguouslydetectedintheHSTimagesdonotseemtobesignificantlyolderthan∼20Myr(Harrisetal.2004).Indeed,thetime–extendedstarformationhistoryforNGC5253isinferrednotfromitsclusters,butfromitsdiffusestellarpopulation,whosecolorsareconsistentwithconstantstarformationoverthepast∼100-200Myr(Calzettietal.1997).Thedearthof‘old’starclustersinNGC5253couldbecausedbyrapidclusterdissolutiontimescalesinthecenterofthegalaxy;byrescalingtheMilkyWaymodelofKim,Morris&Lee1999,Tremontietal.2001andHarrisetal.2004derivedis-solutiontimescalesintherange16–50MyrforNGC5253.Theseshorttimescalesaredrivenbythehighcentralvelocitydispersionmeasuredinthegalaxy(Caldwell&Phillips1989).AsmallervelocitydispersionmaybepresentinNGC3077,asinferredfrommolecularcloudvelocities(Walteretal.2002),implyinglongersurvivaltimesforitsclusters.Contrarytothedwarfs,thedistributionofthestellarclustersinthecenterofthegiantspiralNGC5236showsahighleveloforganization,possiblyareflectionofthedifferentdynamicalenvironment(presenceofabar)inthemassivegalaxy.TheUV–brightclustersaredistributedalongahalf–ringletsurroundingtheoptically–brightnucleus.Thedistributionoftheagesalsoshowsahighlevelofcorrelationinthestarformation,whichappearspropagatingintheS–Ndirectionandinside–outintheringlet(Harrisetal.2001,Puxley,Doyon&Ward1997).Thereisaclearpeakinthenumberofclustersinthenarrowagerange5–7Myr,withahandfulofolderclusters(upto∼50Myr).Althoughthediffusepopulationisgenerallyconsistentwithconstantstarformationoverthepast∼1Gyr,thesharpcut–offoftheclusteragesaround7Myrcouldstillbeexplainedwitheitherarecentstarburstorveryrapidclusterdissolutiontimescales(Harrisetal.2001).Independentlyofwhetherthecurrentstarburstinthegranddesignspiralisconfirmedtobeyoungerthan∼10Myr,aclearmechanismforthetriggeringandfeedingofthestarburst,i.e.gasinfallalongthemainbar,ispresentinNGC5236(Gallaisetal.1991).Nosuchobviousmechanismispresentinthetwodwarfgalaxies.Theirstarburstsmayhavebeentriggeredbypastinteractionswiththeircompanions(M81forNGC3077,andNGC5236forNGC5253),buttheseinteractionsoccurredafewhundredMyrago,andareunlikelytobethedirectcauseofthestarburstsobservedtoday.
