a r X i v :h e p -e x /9908012v 3 3 A p r 2000Measurement of D ?±production
and the charm contribution to F 2
in deep inelastic scattering at HERA
ZEUS Collaboration Abstract The production of D ?±(2010)mesons in deep inelastic scattering has been measured in the ZEUS detector at HERA using an integrated luminosity of 37pb ?1.The decay channels D ?+→D 0π+(+c.c.),with D 0→K ?π+or D 0→K ?π?π+π+,have been used to identify the D mesons.The e +p cross section for inclusive D ?±production with 1 rises from ?10%at Q 2?1.8GeV 2to ?30%at Q 2?130GeV 2for x values in the range 10?4to 10?3. Eur.Phys.J.C 12(2000)35-52 The ZEUS Collaboration J.Breitweg,S.Chekanov,M.Derrick,D.Krakauer,S.Magill,B.Musgrave,A.Pellegrino, J.Repond,R.Stanek,R.Yoshida Argonne National Laboratory,Argonne,IL,USA p M.C.K.Mattingly Andrews University,Berrien Springs,MI,USA G.Abbiendi,F.Anselmo,P.Antonioli,G.Bari,M.Basile,L.Bellagamba,D.Boscherini1, A.Bruni,G.Bruni,G.Cara Romeo,G.Castellini2,L.Cifarelli3,F.Cindolo,A.Contin,N.Cop-pola,M.Corradi,S.De Pasquale,P.Giusti,G.Iacobucci4,https://www.doczj.com/doc/536338922.html,urenti,G.Levi,A.Margotti, T.Massam,R.Nania,F.Palmonari,A.Pesci,A.Polini,G.Sartorelli,Y.Zamora Garcia5, A.Zichichi University and INFN Bologna,Bologna,Italy f C.Amelung,A.Bornheim,I.Brock,K.Cob¨o ken,J.Crittenden,R.De?ner,M.Eckert6, H.Hartmann,K.Heinloth,E.Hilger,H.-P.Jakob,A.Kappes,U.F.Katz,R.Kerger,E.Paul, J.Rautenberg7, H.Schnurbusch,A.Stifutkin,J.Tandler,A.Weber,H.Wieber Physikalisches Institut der Universit¨a t Bonn,Bonn,Germany c D.S.Bailey,O.Barret,W.N.Cottingham,B.Foster8,G.P.Heath,H.F.Heath,J.D.McFall, D.Piccioni,J.Scott,R.J.Tapper H.H.Wills Physics Laboratory,University of Bristol,Bristol,U.K.o M.Capua,A.Mastroberardino,M.Schioppa,G.Susinno Calabria University,Physics Dept.and INFN,Cosenza,Italy f H.Y.Jeoung,J.Y.Kim,J.H.Lee,I.T.Lim,K.J.Ma,M.Y.Pac9 Chonnam National University,Kwangju,Korea h A.Caldwell,W.Liu,X.Liu, B.Mellado,J.A.Parsons,S.Ritz10,R.Sacchi,S.Sampson, F.Sciulli Columbia University,Nevis Labs.,Irvington on Hudson,N.Y.,USA q J.Chwastowski,A.Eskreys,J.Figiel,K.Klimek,K.Olkiewicz,M.B.Przybycie′n,P.Stopa, L.Zawiejski Inst.of Nuclear Physics,Cracow,Poland j L.Adamczyk11,B.Bednarek,K.Jele′n,D.Kisielewska,A.M.Kowal,T.Kowalski,M.Przyby-cie′n,E.Rulikowska-Zar?e bska,L.Suszycki,J.Zaj?a c Faculty of Physics and Nuclear Techniques,Academy of Mining and Metallurgy,Cracow,Poland j Z.Duli′n ski,A.Kota′n ski Jagellonian Univ.,Dept.of Physics,Cracow,Poland k L.A.T.Bauerdick,U.Behrens,J.K.Bienlein,C.Burgard,K.Desler,G.Drews,A.Fox-Murphy, U.Fricke,F.Goebel,P.G¨o ttlicher,R.Graciani,T.Haas,W.Hain,G.F.Hartner,D.Hasell12, K.Hebbel,K.F.Johnson13,M.Kasemann14,W.Koch,U.K¨o tz,H.Kowalski,L.Lindemann, B.L¨o hr,M.Mart′?nez,https://www.doczj.com/doc/536338922.html,ewski15,https://www.doczj.com/doc/536338922.html,ite,T.Monteiro16,M.Moritz,D.Notz,F.Peluc-chi,M.C.Petrucci,K.Piotrzkowski,M.Rohde,P.R.B.Saull,A.A.Savin,U.Schneekloth, O.Schwarzer17,F.Selonke,M.Sievers,S.Stonjek,E.Tassi,G.Wolf,U.Wollmer,C.Young-man,W.Zeuner Deutsches Elektronen-Synchrotron DESY,Hamburg,Germany B.D.Burow18, C.Coldewey,H.J.Grabosch, A.Lopez-Duran Viani, A.Meyer,K.M¨o nig, S.Schlenstedt,P.B.Straub DESY Zeuthen,Zeuthen,Germany G.Barbagli,E.Gallo,P.Pelfer University and INFN,Florence,Italy f G.Maccarrone,L.Votano INFN,Laboratori Nazionali di Frascati,Frascati,Italy f A.Bamberger,S.Eisenhardt19,P.Markun,H.Raach,S.W¨o l?e Fakult¨a t f¨u r Physik der Universit¨a t Freiburg i.Br.,Freiburg i.Br.,Germany c N.H.Brook20,P.J.Bussey,A.T.Doyle,S.W.Lee,N.Macdonald,G.J.McCance,D.H.Saxon, L.E.Sinclair,I.O.Skillicorn,E.Strickland,R.Waugh Dept.of Physics and Astronomy,University of Glasgow,Glasgow,U.K.o I.Bohnet,N.Gendner,U.Holm,A.Meyer-Larsen,H.Salehi,K.Wick Hamburg University,I.Institute of Exp.Physics,Hamburg,Germany c A.Garfagnini,I.Gialas21,L.K.Gladilin22,D.K?c ira23,R.Klanner,E.Lohrmann,G.Poelz, F.Zetsche Hamburg University,II.Institute of Exp.Physics,Hamburg,Germany c T.C.Bacon,J.E.Cole,G.Howell,https://www.doczj.com/doc/536338922.html,mberti24,K.R.Long,https://www.doczj.com/doc/536338922.html,ler,A.Prinias25,J.K.Sedg-beer,D.Sideris,A.D.Tapper,R.Walker Imperial College London,High Energy Nuclear Physics Group,London,U.K.o U.Mallik,S.M.Wang University of Iowa,Physics and Astronomy Dept.,Iowa City,USA p P.Cloth,D.Filges Forschungszentrum J¨u lich,Institut f¨u r Kernphysik,J¨u lich,Germany T.Ishii,M.Kuze,I.Suzuki26,K.Tokushuku27,S.Yamada,K.Yamauchi,Y.Yamazaki Institute of Particle and Nuclear Studies,KEK,Tsukuba,Japan g S.H.Ahn,S.H.An,S.J.Hong,S.B.Lee,S.W.Nam28,S.K.Park Korea University,Seoul,Korea h H.Lim,I.H.Park,D.Son Kyungpook National University,Taegu,Korea h F.Barreiro,J.P.Fern′a ndez, G.Garc′?a,C.Glasman29,J.M.Hern′a ndez30,https://www.doczj.com/doc/536338922.html,barga,J.del Peso, J.Puga,I.Redondo31,J.Terr′o n Univer.Aut′o noma Madrid,Depto de F′?sica Te′o rica,Madrid,Spain n F.Corriveau,D.S.Hanna,J.Hartmann32,W.N.Murray33,A.Ochs,S.Padhi,M.Riveline, D. G.Stairs,M.St-Laurent,M.Wing McGill University,Dept.of Physics,Montr′e al,Qu′e bec,Canada a,b T.Tsurugai Meiji Gakuin University,Faculty of General Education,Yokohama,Japan V.Bashkirov34,B.A.Dolgoshein Moscow Engineering Physics Institute,Moscow,Russia l G.L.Bashindzhagyan,P.F.Ermolov,Yu.A.Golubkov,L.A.Khein,N.A.Korotkova,I.A.Ko-rzhavina,V.A.Kuzmin,O.Yu.Lukina,A.S.Proskuryakov,L.M.Shcheglova35,A.N.Solomin35, S.A.Zotkin Moscow State University,Institute of Nuclear Physics,Moscow,Russia m C.Bokel,M.Botje,N.Br¨u mmer,J.Engelen,E.Ko?eman,P.Kooijman,A.van Sighem, H.Tiecke,N.Tuning,J.J.Velthuis,W.Verkerke,J.Vossebeld,L.Wiggers,E.de Wolf NIKHEF and University of Amsterdam,Amsterdam,Netherlands i D.Acosta36,B.Bylsma,L.S.Durkin,J.Gilmore,C.M.Ginsburg,C.L.Kim,T.Y.Ling,P.Ny-lander Ohio State University,Physics Department,Columbus,Ohio,USA p H.E.Blaikley,S.Boogert,R.J.Cashmore16,A.M.Cooper-Sarkar,R.C.E.Devenish,J.K.Ed-monds,J.Gro?e-Knetter37,N.Harnew,T.Matsushita,V.A.Noyes38,A.Quadt16,O.Ruske, M.R.Sutton,R.Walczak,D.S.Waters Department of Physics,University of Oxford,Oxford,U.K.o A.Bertolin,R.Brugnera,R.Carlin,F.Dal Corso,S.Dondana,U.Dosselli,S.Dusini,S.Li-mentani,M.Morandin,M.Posocco,L.Stanco,R.Stroili,C.Voci Dipartimento di Fisica dell’Universit`a and INFN,Padova,Italy f L.Iannotti39,B.Y.Oh,J.R.Okrasi′n ski,W.S.Toothacker,J.J.Whitmore Pennsylvania State University,Dept.of Physics,University Park,PA,USA q Y.Iga Polytechnic University,Sagamihara,Japan g G.D’Agostini,G.Marini,A.Nigro,M.Raso Dipartimento di Fisica,Univ.’La Sapienza’and INFN,Rome,Italy f C.Cormack,J.C.Hart,N.A.McCubbin,T.P.Shah Rutherford Appleton Laboratory,Chilton,Didcot,Oxon,U.K.o D.Epperson,C.Heusch,H.F.-W.Sadrozinski,A.Seiden,R.Wichmann,D.C.Williams University of California,Santa Cruz,CA,USA p N.Pavel Fachbereich Physik der Universit¨a t-Gesamthochschule Siegen,Germany c H.Abramowicz40,S.Dagan41,S.Kananov41,A.Kreisel,A.Levy41 Raymond and Beverly Sackler Faculty of Exact Sciences,School of Physics,Tel-Aviv University, Tel-Aviv,Israel e T.Abe,T.Fusayasu,M.Inuzuka,K.Nagano,K.Umemori,T.Yamashita Department of Physics,University of Tokyo,Tokyo,Japan g R.Hamatsu,T.Hirose,K.Homma42,S.Kitamura43,T.Nishimura Tokyo Metropolitan University,Dept.of Physics,Tokyo,Japan g M.Arneodo44,N.Cartiglia,R.Cirio,M.Costa,M.I.Ferrero,S.Maselli,V.Monaco,C.Peroni, M.Ruspa,A.Solano,A.Staiano Universit`a di Torino,Dipartimento di Fisica Sperimentale and INFN,Torino,Italy f M.Dardo II Faculty of Sciences,Torino University and INFN-Alessandria,Italy f D.C.Bailey,C.-P.Fagerstroem,R.Galea,T.Koop,G.M.Levman,J.F.Martin,R.S.Orr, S.Polenz,A.Sabetfakhri,D.Simmons University of Toronto,Dept.of Physics,Toronto,Ont.,Canada a J.M.Butterworth,C.D.Catterall,M.E.Hayes,E.A.Heaphy,T.W.Jones,https://www.doczj.com/doc/536338922.html,ne,B.J.West University College London,Physics and Astronomy Dept.,London,U.K.o J.Ciborowski,R.Ciesielski,G.Grzelak,R.J.Nowak,J.M.Pawlak,R.Pawlak,B.Smalska, T.Tymieniecka,A.K.Wr′o blewski,J.A.Zakrzewski,A.F.˙Zarnecki Warsaw University,Institute of Experimental Physics,Warsaw,Poland j M.Adamus,T.Gadaj Institute for Nuclear Studies,Warsaw,Poland j O.Deppe,Y.Eisenberg41,D.Hochman,U.Karshon41 Weizmann Institute,Department of Particle Physics,Rehovot,Israel d W.F.Badgett,D.Chapin,R.Cross,C.Foudas,S.Mattingly,D.D.Reeder,W.H.Smith, A.Vaiciulis45,T.Wildschek,M.Wodarczyk University of Wisconsin,Dept.of Physics,Madison,WI,USA p A.Deshpande,S.Dhawan,V.W.Hughes Yale University,Department of Physics,New Haven,CT,USA p S.Bhadra,W.R.Frisken,R.Hall-Wilton,M.Khakzad,S.Menary,W.B.Schmidke York University,Dept.of Physics,Toronto,Ont.,Canada a 1now visiting scientist at DESY 2also at IROE Florence,Italy 3now at Univ.of Salerno and INFN Napoli,Italy 4also at DESY 5supported by Worldlab,Lausanne,Switzerland 6now at BSG Systemplanung AG,53757St.Augustin 7drafted to the German military service 8also at University of Hamburg,Alexander von Humboldt Research Award 9now at Dongshin University,Naju,Korea 10now at NASA Goddard Space Flight Center,Greenbelt,MD20771,USA 11supported by the Polish State Committee for Scienti?c Research,grant No.2P03B14912 12now at Massachusetts Institute of Technology,Cambridge,MA,USA 13visitor from Florida State University 14now at Fermilab,Batavia,IL,USA 15now at ATM,Warsaw,Poland 16now at CERN 17now at ESG,Munich 18now an independent researcher in computing 19now at University of Edinburgh,Edinburgh,U.K. 20PPARC Advanced fellow 21visitor of Univ.of Crete,Greece,partially supported by DAAD,Bonn-Kz.A/98/16764 22on leave from MSU,supported by the GIF,contract I-0444-176.07/95 23supported by DAAD,Bonn-Kz.A/98/12712 24supported by an EC fellowship 25PPARC Post-doctoral fellow 26now at Osaka Univ.,Osaka,Japan 27also at University of Tokyo 28now at Wayne State University,Detroit 29supported by an EC fellowship number ERBFMBICT972523 30now at HERA-B/DESY supported by an EC fellowship No.ERBFMBICT982981 31supported by the Comunidad Autonoma de Madrid 32now at debis Systemhaus,Bonn,Germany 33now a self-employed consultant 34now at Loma Linda University,Loma Linda,CA,USA 35partially supported by the Foundation for German-Russian Collaboration DFG-RFBR (grant no.436RUS113/248/3and no.436RUS113/248/2) 36now at University of Florida,Gainesville,FL,USA 37supported by the Feodor Lynen Program of the Alexander von Humboldt foundation 38now with Physics World,Dirac House,Bristol,U.K. 39partly supported by Tel Aviv University 40an Alexander von Humboldt Fellow at University of Hamburg 41supported by a MINERVA Fellowship 42now at ICEPP,Univ.of Tokyo,Tokyo,Japan 43present address:Tokyo Metropolitan University of Health Sciences,Tokyo116-8551,Japan 44now also at Universit`a del Piemonte Orientale,I-28100Novara,Italy,and Alexander von Humboldt fellow at the University of Hamburg 45now at University of Rochester,Rochester,NY,USA a supported by the Natural Sciences and Engineering Research Council of Canada(NSERC) b supported by the FCAR of Qu′e bec,Canada c supporte d by th e German Federal Ministry for Education and Science, Research and Technology(BMBF),under contract numbers057BN19P, 057FR19P,057HH19P,057HH29P,057SI75I d supported by th e MINERVA Gesellschaft f¨u r Forschung GmbH,the German Israeli Foundation,and by the Israel Ministry of Science e supported by the German-Israeli Foundation,the Israel Science Foundation, the U.S.-Israel Binational Science Foundation,and by the Israel Ministry of Science f supported by the Italian National Institute for Nuclear Physics(INFN) g supported by the Japanese Ministry of Education,Science and Culture(the Monbusho)and its grants for Scienti?c Research h supported by the Korean Ministry of Education and Korea Science and Engi- neering Foundation i supported by the Netherlands Foundation for Research on Matter(FOM) j supported by the Polish State Committee for Scienti?c Research,grant No.115/E-343/SPUB/P03/154/98,2P03B03216,2P03B04616,2P03B10412, 2P03B03517,and by the German Federal Ministry of Education and Science, Research and Technology(BMBF) k supported by the Polish State Committee for Scienti?c Research(grant No. 2P03B08614and2P03B06116) l partially supported by the German Federal Ministry for Education and Science, Research and Technology(BMBF) m supported by the Fund for Fundamental Research of Russian Ministry for Science and Education and by the German Federal Ministry for Education and Science,Research and Technology(BMBF) n supported by the Spanish Ministry of Education and Science through funds provided by CICYT o supported by the Particle Physics and Astronomy Research Council p supported by the US Department of Energy q supported by the US National Science Foundation 1Introduction The?rst HERA measurements of the charm contribution,F cˉc2,to the proton structure function F2were reported by the H1and ZEUS collaborations from the analyses of their1994deep inelastic scattering(DIS)data sets[1,2].These early results,which were statistically limited, revealed a steep rise of F cˉc2as Bjorken-x decreases.At the lowest accessible x values,it was found that around25%of DIS events contained open charm,in contrast to the EMC?xed target measurements[3]in the high-x region where the charm contribution is small.Given the large charm content,the correct theoretical treatment of charm for F2analyses in the HERA regime has become essential.More detailed measurements of charm production will aid such analyses. The early results[1,2]suggested that the production dynamics of charmed mesons in ep collisions are dominated by the boson-gluon-fusion(BGF)mechanism shown in Fig.1.In this case,the reactions e+p→e+D?±X are sensitive to the gluon distribution in the proton[4]. The measurement of charm production can also provide tests of perturbative QCD(pQCD), in particular,tests of the hard scattering factorization theorem,which states that the same, universal,gluon distribution should contribute to both F2and F cˉc2.In addition,the presence of two large scales,namely,the virtuality of the exchanged boson(Q2)and the square of the charm-quark mass(m2c),provides a testing ground for resummation techniques. This paper reports a measurement of D?±(2010)production using the1996and1997data sets collected with the ZEUS detector,corresponding to an integrated luminosity of37pb?1. During this period,HERA collided E e=27.5GeV positrons with E p=820GeV protons, √ yielding a center-of-mass energy, mass,variable-?avor-number scheme(ZM-VFNS).In this scheme,the resummation of large logarithms of Q2/m2c[9,10]results in a charm density which is added as a fourth?avor and which is then evolved in the same way as the light quark densities.At intermediate Q2values, the two schemes need to be merged.One way in which this is done is described by ACOT[9] and by Collins[11].An alternative matching method has been proposed by MRST[12]. A third method for modelling D?±production has recently been suggested by BKL[13]. This tree-level pQCD calculation,applicable for p T≥m c,considers the hadronization of the (cˉq)-state into a D?,in contrast to hadronizing an isolated c-quark.The D?is created from both color singlet and color octet con?gurations of the light and heavy quarks.Results from e+e?annihilation imply that the octet contribution is small.However,the singlet contribution alone underestimates[13]the ZEUS data on the photoproduction of charm[14].This calculation has been extended to DIS charm production and is compared to the D?±data reported here. 3Experimental setup ZEUS is a multipurpose detector which has been described in detail elsewhere[15].The key component for this analysis is the central tracking detector(CTD)which operates in a magnetic ?eld of1.43T provided by a thin superconducting solenoid.The CTD[16]is a drift chamber consisting of72cylindrical layers,arranged in9superlayers covering the polar angle1region 15?<θ<164?.The transverse momentum resolution for full-length tracks isσ(p T)/p T= 0.0058p T 0.0065 0.0014/p T(p T in GeV).The CTD was also used to establish an interaction vertex for each event. The uranium-scintillator sampling calorimeter(CAL)surrounds the solenoid.The CAL is hermetic and consists of5918cells,each read out by two photomultiplier tubes.The CAL contains three parts,the forward(FCAL),barrel(BCAL)and rear(RCAL),with longitudinal segmentation into electromagnetic and hadronic sections.The energy resolutions,as measured in test beams,areσ/E=0.18/ E(GeV)for electrons and hadrons,re-spectively[17]. The position of positrons scattered close to the positron beam direction is determined by a scintillator strip detector(SRTD)[18].The luminosity was measured from the rate of the bremsstrahlung process,e+p→e+γp,where the photon is measured by a lead/scintillator calorimeter[19]located at Z=?107m in the HERA tunnel. 4Kinematics and reconstruction of variables The reaction e+(k)+p(P)→e+(k′)+X at?xed squared center-of-mass energy,s=(k+P)2, is described in terms of Q2=?q2=?(k?k′)2and Bjorken-x=Q2/(2P·q).The fractional energy transferred to the proton in its rest frame is y=Q2/(sx).The virtual photon(γ?)-proton center-of-mass energy W,given by W2=(q+P)2,is also used,see Fig.1. In neutral current(NC)e+p DIS,both the?nal-state positron,with energy E′e and angle θ′e,and the hadronic system(with a characteristic angleγh,which,in the simple quark-parton model,is the polar angle of the struck quark)can be measured.The scattered positron was identi?ed using an algorithm based on a neural network[20].CAL cells were combined to form clusters and combinations of these clusters and CTD tracks were used to reconstruct energy- ?ow objects(EFO’s)[21,22].For perfect detector resolution and acceptance,the quantity δ≡Σi(E i?p z,i)is equal to2E e(55GeV).Here,E i and p z,i are the energy and longitudinal component of the momentum assigned to the i-th EFO.The sum runs over all EFO’s including those assigned to the scattered positron. In the K2πanalysis,Q2was reconstructed from the scattered positron(Q2e)with the electron method[23]and y with the so-calledΣmethod[24] δhad yΣ= ,(2) W where p?(D?)is the D?±momentum in theγ?p center-of-mass frame.For the boost to theγ?p system,the virtual-photon vector was reconstructed using the double-angle(DA)estimator[23] of the scattered positron energy,E′DA.In this method,only the anglesθ′e andγh are used[25]. E′DA is less sensitive to radiative e?ects at the leptonic vertex than the scattered e+energy determined using the electron method. For the K4πanalysis,Q2,x and W were determined using the DA estimators(Q2DA,x DA and W DA). 5Monte Carlo simulation A GEANT3.13-based[26]Monte Carlo(MC)simulation program which incorporates the best current knowledge of the ZEUS detector and trigger was used to correct the data for detector and acceptance e?ects.The event generator used for the simulation of the QED radiation from the leptonic vertex was RAPGAP[27]interfaced to HERACLES4.1[28].The charm quarks were produced in the BGF process calculated at leading order(LO).The charm mass was set to1.5GeV.The GRV94HO[29]parton distribution functions(pdf’s)were used for the proton.Fragmentation was carried out using the Lund model[30],as implemented in JETSET 7.4[31],with the full parton shower option.The fraction of the original c-quark momentum which is carried by the D?±is determined from the‘SLAC’fragmentation function,which is equivalent to the Peterson model[32],with the fragmentation parameter?set to0.035[33]. The HERWIG5.9[34]event generator was also used,with the same pdf’s and c-quark mass as used in RAPGAP,to investigate the e?ects of fragmentation. Generated events with at least one D?+→D0π+s→(K?π+or K?π+π?π+)π+s(or c.c.) were selected.These events were then processed through the detector and trigger simulation and through the same reconstruction program as was used for the data. 6Event selection 6.1Trigger Events were selected online with a three-level trigger[15].At the?rst level(FLT),inclusive DIS events are triggered by the presence of an isolated electromagnetic cluster in the RCAL or any energy deposition in excess of3GeV in any electromagnetic section of the CAL[35]. During high-luminosity periods,when the rate was high,a coincidence with an FLT track was also required.Tracks at the FLT are de?ned as a series of CTD hits pointing to the nominal interaction point.The e?ciency of this trigger,with respect to the calorimeter-only trigger, was greater than99.5%and in good agreement with the MC simulation. At the second level,algorithms are applied to reduce the non-e+p background.The full event information is available at the third level trigger(TLT).At this level,events are accepted as DIS candidates if a high-energy scattered positron candidate is found within the CAL(‘in-clusive DIS trigger’).Because of the high rate of low-Q2events,this trigger was turned o?in the region around the RCAL beampipe during high-luminosity operation.For the K2πdecay channel,a D?-?nder(based on computing the Kππmass using tracking information and se-lecting loosely around the D?±mass)was available in the TLT.Events at low Q2were then kept by requiring a coincidence of an identi?ed scattered positron anywhere in the CAL and a tagged D?±candidate.This will be referred to as the‘D?trigger’. Using data selected from periods when both triggers were in use,the relative e?ciency of the D?trigger with respect to the inclusive DIS trigger is found to be about80%and independent of Q2,x,p T(D?)andη(D?)within the measured kinematic regions.The MC simulations reproduce this e?ciency to an accuracy better than the statistical accuracy of the data(≈2%). 6.2O?ine selection The DIS event selection was similar to that described in an earlier publication[36];namely,the selection required: ?a positron,as identi?ed by a neural network algorithm,with a corrected energy above10 GeV; ?the impact point of the scattered positron on the RCAL was required to lie outside the region26×14cm2centered on the RCAL beamline; ?40<δ<65GeV;and ?a Z-vertex position|Z vtx|<50cm. The DIS events were restricted to the kinematic region ?1 D?±candidates were reconstructed from CTD tracks which were assigned to the recon-structed event vertex.Only tracks with at least one hit in the third superlayer of the CTD were considered.This corresponds to an implicit requirement that p T>0.075GeV.Tracks were also required to have|η|<1.75,where the pseudorapidity is de?ned asη=?ln(tanθ D0→K?π+π?π+(+c.c.).The branching ratio for D0to Kπ(K3π)is0.0385±0.0009(0.076±0.004)[37].The remaining selection criteria were di?erent for the two?nal states and are discussed separately. 6.3Selection for the K2π?nal state Pairs of oppositely-charged tracks were?rst combined to form a D0candidate.Since no particle identi?cation was performed,the tracks were alternatively assigned the masses of a charged kaon and a charged pion.An additional slow track,with charge opposite to that of the kaon track and assigned the pion mass(πs),was combined with the D0candidate to form a D?±candidate. The combinatorial background for the K2πdecay channel was further reduced by requiring ?that the transverse momenta of the K and theπwere greater than0.4GeV,and that of theπs was greater than0.12GeV. In addition,the momentum ratio requirement ?p(D0)/p(πs)>8.0 was imposed.This requirement was used in the D?trigger to reduce the rate of candidate events with large?M≡(M Kππs?M Kπ),far from the signal region. The D?±kinematic region of the present analysis was de?ned as ?1.5 Finally,the signal regions for the mass of the D0candidate,M(D0),and?M were ?1.80 ?143 6.4Selection for the K4π?nal state Permutations of two negatively-and two positively-charged tracks were?rst combined to form a D0candidate.As for the K2πchannel,the tracks were alternatively assigned the masses of a charged kaon and a charged pion.An additional track,with charge opposite to that of the kaon track and assigned the pion mass(πs),was combined with the D0candidate to form a D?±candidate.The combinatorial background for the K4πdecay channel was reduced by requiring ?that the transverse momentum of the K and eachπwas greater than0.5and0.2GeV, respectively,and that of theπs was greater than0.15GeV. In addition,the momentum ratio requirement ?p(D0)/p(πs)>9.5 was imposed. The D?±kinematic region was de?ned as ?2.5 The signal regions for M(D0)and?M≡(M Kππππs?M Kπππ)were ?1.81 ?143 6.5Mass distributions Figures2(a)and(c)show the distributions of M(D0)for candidates with?M in the signal region for the two?nal states,while Figs.2(b)and(d)show the distributions of?M for candidates with M(D0)in the signal region.Clear signals are observed around the expected mass values. For the K2π?nal state,a?t to the M(D0)distribution of two Gaussians plus an exponen-tially falling background gives a peak at M(D0)=1863.2±0.8MeV and a width of23±2MeV. The second Gaussian around1.6GeV in Fig.2(a)originates primarily from D0decays to K?π+π0in which the neutral pion is not reconstructed.For the K4πchannel,the background level was determined by using the side-bands outside the?M signal region(see the dashed histogram in Fig.2(c))to make a M(D0)distribution.The?t to the M(D0)distribution,made by adding a Gaussian to the background distribution,yielded M(D0)=1862.7±1.5MeV and a width of20±2MeV.The deviations of the data from the?t,visible in the region just above the signal in Fig.2(c),are mostly due to the mass misassignments of the K andπcandidates with the same charge from D0decay.This was veri?ed by MC studies[38].The mass values found for the D0are consistent with the PDG[37]value of1864.6±0.5MeV. The solid curve in Fig.2(b)shows a binned maximum-likelihood?t to the?M distri-bution from the K2πchannel using a Gaussian plus a background of the form A(?M?mπ)B exp[C(?M?mπ)],where A,B and C are free parameters and mπis the pion mass. The?t to the K2πplot gives a peak at?M=145.44±0.05MeV,in good agreement with the PDG value of145.397±0.030MeV,and a width of0.79±0.05MeV,in agreement with the experimental resolution.The multiplicative exponential term is needed to describe the background suppression at large?M,which comes from the requirement on the momentum ratio p(D0)/p(πs). The solid curve in Fig.2(d)shows a?t of the?M distribution from the K4πchannel using a Gaussian plus a background distribution obtained from the side-bands outside the M(D0) signal region(see the dashed histogram in Fig.2(d)).The?t yields a peak at?M=145.61±0.05MeV and a width of0.78±0.07MeV. For the K2πchannel,the number of D?±events obtained from a?t to the?M distribution in the restricted region of Q2,y,p T(D?)andη(D?)is2064±72.The number of events in the K4πchannel is determined from the?M distribution using the side band method[14],which properly accounts for the combinatorial background and the background arising from the mass misassignments.The side bands,1.74 7Data characteristics The properties of the selected events are compared with those of the RAPGAP Monte Carlo simulation.All distributions shown are background-subtracted since they represent the number of signal events obtained by?tting the various mass distributions in a given bin.The data for the K2πchannel are shown in Figs.3and4as solid points and the RAPGAP simulation as shaded histograms.All MC plots are normalized to have the same area as the data distributions. Figure3shows histograms of E′e,θ′e,γh andδand Fig.4(a-c)displays the distributions of Q2e,x eΣand W eΣ.In general,reasonable agreement is observed between data and the MC simulation.Figure4(d-f)shows the transverse momentum,p T(D?),the pseudorapidity,η(D?), and the energy fraction carried by the D?±in theγ?p center-of-mass frame,x(D?).Although the p T(D?)spectrum of the data is well described,the MC pseudorapidity spectrum is shifted to lowerηcompared to the data and the x(D?)spectrum for the MC is shifted to slightly larger values.These discrepancies are examined in more detail below. The HERWIG[34]Monte Carlo was used for systematic studies.This MC describes the D?±di?erential distributions better than RAPGAP,but does not give as good agreement with the DIS variables as RAPGAP since it does not contain QED radiative e?ects. Photoproduction,where the?nal positron is scattered through very small angles and escapes undetected through the RCAL beamhole,is a possible background source.Hadronic activity in the RCAL can be wrongly identi?ed as the scattered positron,giving rise to fake DIS events. The e?ect was investigated using a large sample of photoproduced D?±events generated with the HERWIG MC.After the?nal selection cuts the photoproduction contamination is found to be less than1%,much smaller than the statistical error of the measurement,and so is neglected. The overall contribution to D?±production from b quark decays in the measured kinematic region is estimated to be less than2%,using HVQDIS with m b=4.5GeV and a hadronization fraction of b→D?of0.173[39].A similar study using RAPGAP yields an estimate of～1% at low Q2and less than3%at high Q2.Hence the contribution from b quark decays has been neglected. 8Systematic uncertainties The experimental systematic uncertainties in the cross section are grouped into several major categories: ?Systematic uncertainties related to the inclusive DIS selection of the events:variations were made in the y cut,the RCAL box cut,and the vertex position cut.In addition,for the K2π?nal state both Q2and y were determined using the DA method rather than using the eΣmethod.The combined variations resulted in a change of±1.5%to the nominal cross section.For the K4πchannel,the electron method was used rather than the DA method and the combined variations resulted in a change of±4.7%.?Systematic uncertainties in the D?±selection:for the K2π?nal state,the minimum transverse momentum of tracks used in the D?±reconstruction was raised and lowered by up to100MeV for the K andπand by25MeV for theπs and resulted in a±4.5% variation.The momentum ratio p(D0)/p(πs)was raised by+0.5and yielded a negligible change.For the K4πchannel,similar changes in the minimum transverse momenta and varying p(D0)/p(πs)by±0.5combine to give a±8.5%variation.?Systematic uncertainties related to the estimation of the number of events and back-ground uncertainty:for the K2πanalysis,aχ2?M-?t instead of a(binned)logarithmic-likelihood?t was performed.The M(D0)signal range,within which the?M distributions were?tted,was varied by±10MeV.These variations resulted in a change of±2.5%.For the K4πanalysis,the M(D0)signal range was also varied by±10MeV and the width of the side-bands used to estimate combinatorial background was varied.These variations resulted in a change of±5.8%. ?The systematic uncertainty related to the MC generator was estimated for the K2πanal-ysis by using the HERWIG MC generator to calculate the corrections for the cross section determination.This variation yields a change of-1.3%.The larger overall systematic un-certainty for the K4πchannel means that this systematic uncertainty was negligible for this channel. ?Since approximately10%of the D?±events[40]are produced through a di?ractive mech-anism which was not included in the Monte Carlo generators used to correct the data, acceptance corrections have also been obtained using a sample of di?ractive events gen-erated with RAPGAP.The di?erence in the global correction factor for the di?ractive events was less than10%.This yielded a1.3%variation in the overall cross section and was neglected. ?The systematic uncertainty related to the trigger for the K2π?nal state was estimated to be±1%by an analysis using only the inclusive DIS triggers and was neglected.?The overall normalization uncertainties due to the luminosity measurement error of ±1.65%,and those due to the D?±and D0decay branching ratios[37]were not included in the systematic uncertainties. The systematic uncertainties were added in quadrature.The total systematic uncertainty is less than the statistical error for most of the di?erential distributions and is of the same order as the statistical error for the integrated cross section. 9Cross sections The cross sections for a given observable Y were determined from the equation: dσ (3) A·L·B·?Y where N is the number of D?±events in a bin of?Y,A is the acceptance(including migrations, e?ciencies and radiative e?ects)for that bin,L is the integrated luminosity and B is the product of the appropriate branching ratios for the D?±and D0. The RAPGAP MC was used to estimate the acceptance.In the K2π(K4π)kinematic region the overall acceptance was25.4(18.0)%.The statistical error of the MC is negligible compared to that of the data. The measured cross section in the region1 σ(e+p→e+D?±X)=8.31±0.31(stat.)+0.30 ?0.50(syst.)nb, and for2.5 σ(e+p→e+D?±X)=3.65±0.36(stat.)+0.20 ?0.41(syst.)nb. These results are in good agreement with the HVQDIS[6]calculations of8.44and4.13nb, respectively.The parton distribution functions resulting from a ZEUS NLO QCD?t[41]to the ZEUS,NMC and BCDMS data were used in these calculations.In this?t,only the gluon and three light quark?avors were assumed to be present.HVQDIS fragments the charm quark to a D?±using the Peterson fragmentation function.For the above calculation,m c was set to1.4GeV,the Peterson fragmentation parameter?=0.035,and the mass factorization and renormalization scales were both set to 2Note that this procedure keeps the cross section in the overall phase space in p T(D?)andη(D?)equal to the HVQDIS result and is equivalent to applying the RAPGAP fragmentation to the HVQDIS charm quark prediction. 3Some double counting may occur between the NLO calculations and the parton shower,which contains resummed terms of all orders.This e?ect is estimated to be small from the calculations with the parton shower option in JETSET switched o?. (cˉq)-state.The relative weight of these color con?gurations has been taken from comparisons of the BKL calculation to the published ZEUS D?cross sections in photoproduction[14].The calculation shows reasonable agreement with these DIS data. Tables2and3give the resulting integrated cross sections binned in Q2and y for the K2πand K4π?nal states,respectively.The bin widths were chosen such that they contained of the order of100signal events.The resulting purity in each bin is better than70%.The resolutions in both Q2and y are better than10%in all bins.These bins were chosen to measure F cˉc2 as described in the next section.Tables2and3also show the HVQDIS predictions for the di?erent kinematic bins.The predictions are in good agreement with the data. The quantitative agreement obtained between data and the HVQDIS calculation displayed in Fig.5and Tables2and3represents a con?rmation of the hard scattering factorization theorem, in that the same gluon and three light-quark-?avor parton distributions describe both the ZEUS F2data and the D?±di?erential cross sections reported here.In view of the agreement observed here,the HVQDIS program can be used to extrapolate outside the accessible kinematic region to obtain the total D?±cross section. 10Extraction of F cˉc2 The charm contribution,F cˉc2,to the proton structure function F2can be related to the double di?erential cˉc cross section in x and Q2by d2σcˉc(x,Q2) xQ4{[1+(1?y)2]F cˉc2(x,Q2)?y2F cˉc L(x,Q2)}.(4) In this paper,the cˉc cross section is obtained by measuring the D?±production cross section and employing the hadronization fraction f(c→D?+)to derive the total charm cross section. Since only a limited kinematic region is accessible for the measurement of D?±,a prescription for extrapolating to the full kinematic phase space is needed.The contribution of F cˉc L(x,Q2)to the cross section in the measured Q2,y region is estimated from the NLO theoretical prediction[45] to be less than1%and is therefore neglected.Equation(4)de?nes F cˉc2as arising from events with one or more charm particles in the?nal state,but it is not a unique theoretical de?nition. It depends on the scheme and parton distributions[46]. In order to measure the contribution of charm to the inclusive F2,the integrated cross sections in the Q2and y kinematic bins of Tables2and3were extrapolated to the full p T(D?)andη(D?) phase space using HVQDIS with the RAPGAP-based fragmentation corrections discussed in the previous section.Typical extrapolation factors for the K2π(K4π)?nal state were between 4(10),at low Q2,and1.5(4),at high Q2.This procedure neglects the possibility of additional contributions outside the measured region due,for example,to intrinsic charm[47]. The extrapolated cross sections are converted into cˉc cross sections using the hadronization fraction of charm to D?+:f(c→D?+)=0.222±0.014±0.014[39].The use of this value from OPAL implicitly assumes that charm production in DIS and e+e?annihilation produces the same fractions of the various charm?nal-states.The production of charm bound states, such as e+p→e+J/ψX,is not accounted for when using the LEP c→D?+branching fraction. However,the inelastic J/ψcross section has been calculated[48]to be only2.5-4.5%of the total charm production cross section predicted by HVQDIS in the Q2,y range of this analysis. The elastic J/ψcross section has been measured in DIS[49]and is less than0.5%of the predicted total charm cross section in the range of that measurement.The9%uncertainty on the c→D?+hadronization is larger than that arising from these J/ψcontributions,which have consequently been neglected. The systematic uncertainty on the extrapolation of the measured D?±cross sections to the full p T(D?)andη(D?)phase space was investigated:varying the parameter m c by±0.15GeV gave a variation which was typically<5%;using the standard Peterson fragmentation parameter ?=0.035(instead of the RAPGAP fragmentation correction)yielded changes typically<15%; and using the GRV98HO pdf’s in the NLO calculation generally caused changes of<20%. If these uncertainties are added in quadrature,they are typically smaller than the statistical errors.However,the fact that the data are measured in a small part of the available phase space means that a realistic uncertainty on the extrapolation cannot be evaluated.Therefore these extrapolation uncertainties are not included in the systematic uncertainties discussed below. Since the structure function varies only slowly,it is assumed to be constant within a given Q2and y bin,so that the measured F cˉc2in a bin i is given by F cˉc2 meas (x i,Q2i)= σi,meas(e+p→D?X) 4m2c+Q2)have been used as for the HVQDIS calculation of the di?erential cross sections. 10.1Combination of F cˉc2from both decays Finally,the results from the two decay channels were combined in the eight common bins,tak-ing into account all systematic uncertainties.The combined value is a weighted average with weights according to the statistical precision of the individual measurements.The systematic uncertainties were assumed to be either uncorrelated or100%correlated between the analy-ses,as appropriate.All uncertainties concerning the DIS event selection were assumed to be correlated.Only the e?ect of the variation of the D0mass window and the changes in the p T requirements for the D0decay products were taken as uncorrelated.As in both analyses,the positive and negative errors were treated separately.The procedure leads to a gain in statistical precision of5-25%,compared to using only the K2πdecay channel. 10.2Results and discussion Table4and Fig.7display the F cˉc2values in the various Q2bins as a function of x.The structure function F cˉc2shows a rise with decreasing x at constant values of Q2.The rise becomes steeper at higher Q2. The curves in Fig.7represent the results of the NLO QCD calculation[45]with the ZEUS NLO QCD pdf’s.The central,solid curve corresponds to a charm quark mass of1.4GeV. Since good agreement was obtained between data and the HVQDIS calculation for the D?±di?erential cross sections and for the integrated cross sections shown in Tables2and3and since that calculation was used to extrapolate to the full kinematic range,the curves would be expected to describe the resulting values of F cˉc2.The total uncertainty in the calculation of F cˉc2,shown as the band of dashed curves around the solid curve,corresponds to the uncertainty propagated from the ZEUS NLO QCD?t and is dominated by the uncertainty in the charm quark mass,which was varied from1.2to1.6GeV. Figure8shows F cˉc2at constant x values as a function of Q2.Although the number of points is small,large scaling violations of the structure function are evident.The curves superimposed on the data are from the same calculation as shown in Fig.7. Figure9shows the ratio of F cˉc2to F2,the inclusive proton structure function,as a function of x in?xed-Q2bins.The curves superimposed on the data are again from the calculation used for Fig.7.The values of F2used to determine the ratio were taken from the ZEUS NLO QCD ?t at the same Q2and x for which F cˉc2is quoted.The error on F2is negligible in comparison to F cˉc2.The charm contribution to F2rises steeply with decreasing x.In the measured x region,F cˉc2accounts for<10%of F2at low Q2and x?5·10?4and rises to?30%of F2for Q2>11GeV2at the lowest x measured.The strong rise of F cˉc2at low values of x is similar to that of the gluon density and thus supports the hypothesis that charm production is dominated by the boson-gluon-fusion mechanism. 11Summary This paper presents an analysis of D?±production in DIS using the combined ZEUS1996and 1997data samples with an integrated luminosity of37pb?1,about ten times larger than in the previous ZEUS study.In addition,both the K2πand K4πdecay modes of the D?have been employed and their results combined.In the experimentally accessible region of1.5(2.5) ?0.50(sys)nb (3.65±0.36(stat)+0.20 ?0.41(sys)nb). QCD calculations of charm production based on the NLO boson-gluon-fusion process with three?avors of light quarks show excellent agreement with the overall cross section and with the Q2and y distributions.Theη(D?)and x(D?)distributions,however,cannot be reproduced with the standard Peterson fragmentation.Good agreement is obtained after a more appropriate c→D?+fragmentation,such as that in JETSET,is used. The quantitative agreement between the NLO pQCD calculations and the ZEUS data pro-vides a con?rmation of the hard scattering factorization theorem,whereby the same gluon density in the proton describes both the inclusive F2and the DIS production of charm. The charm contribution,F cˉc2,to the proton structure function F2was obtained using the NLO QCD calculation to extrapolate outside the measured p T(D?)andη(D?)https://www.doczj.com/doc/536338922.html,pared to the previous ZEUS study,the kinematic range has been extended down to Q2=1.8GeV2and up to Q2=130GeV2,with reduced uncertainties.The structure function F cˉc2exhibits large scaling violations,as well as a steep rise with decreasing x at constant Q2.For Q2>11GeV2 and x?10?3,the ratio of F cˉc2to F2is about0.3. 12Acknowledgements We thank the DESY Directorate for their strong support and encouragement.The remarkable achievements of the HERA machine group were essential for the successful completion of this work and are gratefully appreciated.We also acknowledge the many informative discussions we have had with J.Amundson,A.Berezhnoy,J.Collins,S.Fleming,B.Harris,F.Olness,C. Schmidt,J.Smith,W.K.Tung and A.Vogt. References [1]H1Collab.,C.Adlo?et al.,Z.Phys.C72,593(1996) [2]ZEUS Collab.,J.Breitweg et al.,Phys.Lett.B407,402(1997) [3]EMC Collab.,J.J.Aubert et al.,Nucl.Phys.B213,31(1983) [4]H1Collab.,C.Adlo?et al.,Nucl.Phys.B545,21(1999) [5]S.Nussinov,Phys.Rev.Lett.35,1672(1975) [6]B.W.Harris and J.Smith,Phys.Rev.D57,2806(1998) [7]B.W.Harris and J.Smith,Nucl.Phys.B452,109(1995);Phys.Lett.B353,535(1995) [8]https://www.doczj.com/doc/536338922.html,enen et al.,Nucl.Phys.B392,162(1993);ibid.,B392,229(1993) [9]M.A.G.Aivazis et al.,Phys.Rev.D50,3102(1994) [10]M.Buza et al.,Phys.Lett.B411,211(1997) [11]J.C.Collins,Phys.Rev.D58,094002(1998) [12]A.D.Martin et al.,Eur.Phys.J.C4,463(1998) [13]A.V.Berezhnoy,V.V.Kiselev and A.K.Likhoded,hep-ph/9901333v2(1999)and hep- ph/9905555(1999) [14]ZEUS Collab.,J.Breitweg et al.,Eur.Phys.J.C6,67(1999) [15]ZEUS Collab.,M.Derrick et al.,The ZEUS Detector,Status Report1993,DESY(1993) [16]N.Harnew et al.,Nucl.Instr.and Meth.A279,290(1989); B.Foster et al.,Nucl.Phys.B(Proc.Suppl.)32,181(1993); B.Foster et al.,Nucl.Instr.and Meth.A338,254(1994) [17]M.Derrick et al.,Nucl.Instr.and Meth.A309,77(1991); A.Andresen et al.,ibid.,101(1991); A.Caldwell et al.,ibid.A321,356(1992); A.Bernstein et al.,ibid.A336,23(1993) [18]A.Bamberger et al.,Nucl.Instr.and Meth.A401,63(1997) [19]J.Andruszk′o w et al.,DESY92-066(1992) [20]H.Abramowicz,A.Caldwell and R.Sinkus,Nucl.Instr.and Meth.A365,508(1995) [21]ZEUS Collab.,M.Derrick et al.,Eur.Phys.J.C1,81(1998);ibid.C6,43(1999) [22]G.Briskin,PhD Thesis,University of Tel Aviv,(1998)unpublished 实验方案 为满足目前纺织染整行业印染废水排放标准的要求，原有的处理工艺已无法满足当前的排放要求，需要对其进行提标改建。从而达到更低的排放要求。由于当前污水处理车间占地面积有限，新建场地较少。根据目前的实际情况，设计了如下小试实验方案： 方案1：基于完全混合活性污泥，根据镜检污泥结构、实际生化池泡沫等问题提出的PACT工艺，即：通过向活性污泥中投加粉末活性炭。一方面，改善污泥结构；另一方面，对生化池泡沫起到一定的吸附消泡，提高污水处理效果的方法。 控制节点：主要对活性炭的加入量以及污泥浓度等进行调控，连续运行观察试验效果及处理效率。 所需材料：活性炭 方案2：由于粉末活性炭的比表面积大，孔隙率小；吸附作用占主体；并且随着实验的进行，活性炭逐渐趋于饱和。受活性炭再生困难的影响，活性炭与活性污泥完全混合，随污泥排放逐渐流失，进而失去其可持续效果。针对此情况，提出向小试实验中投加悬浮载体，形成MBBR工艺，对污水进行强化处理。该 工艺是活性污泥法与生物膜法的结合，集活性污泥法运转灵活，生物膜法污泥浓度高、生物相丰富、可有效避免污泥膨胀等优势相结合。 控制节点与关键：启动过程填料添加过程，分次添加，每次添加以不拥堵为准，均匀分布于废水中，静置30 min；曝气，静置；添加填料（填料填充比例按照30%）；运行过程按照活性污泥法，污泥浓度与活性污泥法一致。填料无须冲洗；生化池出口以滤网或筛网拦截悬浮轻质填料；主要观察试验处理效果。 所需材料：轻质悬浮载体填料（鲍尔环、多面空心球、花环填料、全新PP 悬浮生物填料等） 方案3：从污水处理的整个污水处理工艺单元来看，退浆水经过了厌氧处理，进入调节池，然后与东西进水混合，由于东西进水的成分中依然含有一些难降解的成分需要进行预处理，建议对调节池的出水进行水解酸化处理后，然后进入后续单元；小试装置基于此原理设计了以调节池作为进水的实验流程。 大米进口流程 一、经营资质：中国企业要从事进口大米业务，除了一般经营性企业所必须 的工商、税务、对外贸易资格等手续外，在注册的营业范围内还应包括大米经营资格，具备卫生许可证。二、关税率： 1、大米是进口配额产品，配额内关税率1%，配额外关税率65%； 2、没有其他关税优惠规定；三、增值税率：13% 四、进口监管条件： 1、《关税配额证明》------由商务部签发； 2、进口商检------需申请标签备案。五、一般贸易方式的进口流程 1、配额申请 由于大米属于实施进口关税配额管理的商品（持有《关税配额证明》的征收1%进口关税，否则征收65%进口关税），每年11月份，向商务部申请下一年度进口关税配额证明，商务部根据本企业上一年度的进口情况进行审批。需提交的申请资料如下：A、申请表；B、申请报告；C、企业营业执照；D、对外采购订单。2、商标备案（中文注册商标） 此工作需要客户自行申请，到当地出入境检验检疫局领取标签审核申请表，并准备如下材料：A、企业营业执照； B、大米质量检验检疫报告（需将所需进口的大米样品由国家出入境检验检疫总局检验并出具检验报告）； C、国内经营企业的申请报告； D、生产厂商《生产许可证》复印件及译文（此证应由出产国当地官方机构出具）； E、生产厂商《卫生许可证》复印件及译文（此证应由出产国当地官方机构出具）； F、生产厂商《大米生产工艺流程》复印件及译文（只需要简单的大米生产工艺流程说明示意，并加盖企业印章或负责人签署）； G 、中文商标设计样张（保留原正面标签显示的外文，并在中文标签上 必须有对应译文，且中文品名字体要大于外文品名字体，中文必须是简体中文。样张必须是原样大小，可以是彩色打印件）。 ***注：中文商标样张（3张）；原标签及中文翻译件（各3张）------注明产地。 备齐以上资料，在货物抵达进口口岸前两个月，向当地出入境检验检疫局申请标签备案，通过当地出入境检验检疫局上报国家总局批准，发放《进口食品、化妆品标签备案凭证》，一款大米对应一个商标。如果一款大米再申请一个商标，大米的中文名称不得相同。3、进口商检 大米的进口手续是先商检后报关，假如商检未通过，货物不准入关，要被退运。商检所需提供的资料如下：A、商检报检单；B、标签备案凭证；C、成份表；D、中文商标样张；E、原标签及中文翻译件； F、国内经营企业的“卫生许可证”及“营业执照”复印件； G、出口国出具的《卫生许可证》、《生产许可证》复印件及译文； H、出口国出具的《卫生免疫证》、《原产地证》、《质量保证书》及译文；（随货文件，一批一证） I、对外采购合同、发票、装箱单； J、进口代理协议复印件； K、如果是采用木质包装的，要提供出口国的《木质包装熏蒸证明》；木 质包装上需有“IPPC”标识及熏蒸国家的条形码。 商检局要在口岸货物监管区对货物进行核对：包装是否符合标准，中文注册商标是否完备，还要对所提供的文件资料进行审核，另外，要对货物进行抽检，检验是否符合国家进口食品卫生标准。 ***注：需进口的大米应根据《食品标签通用标准》和有关规定加贴中文标签。 4、海关报关 完成以上工作后，即可向进口地海关申报，向海关申报需要提供如下资料： A、原厂发票； B、装箱单； C、原产地证； D、关税配额证明； E、提、运单； F、货物保险单； G、商检通关单； H、货物的付汇证明等价格资料；I、进口代理协议复印件。 声母d t 一、活动目标: 1、学习声母d t,能读准音认清形,并能正确书写。 2、能借用所学拼音d t与生活环境发生联系,培养幼儿的想象力、 二、活动准备: 教具:拼音卡片、课件、 学具:幼儿描红用书、铅笔盒 三、活动重点: 幼儿正确的发音 四、活动难点: 区分b d , f t 五、活动过程: (一) 激发兴趣 今天来了两个新的拼音宝宝,瞧瞧她们就是谁？一个就是b的兄弟d,一个就是f的兄弟t。 (二)指导认知 1、跟读d指导幼儿正确发音, 2、辨别形:b、d就是兄弟,虽然她们长的象,但也有不一样的地方,仔细瞧瞧它们那里不象,引导幼儿正确辨认d。 3、跟读t,并同样方法辨认f、t的相同点与不同点。让幼儿认准t的形。 4、瞧拼音课件,跟读d、t的发音, 5、游戏传卡复习d t的读音 (三)复习巩固 1、听老师口令举卡复习对d、t、b、f的认识。 2、听口令,用绳摆出d t 的外形、 (四)迁移运用 1、d像什么？t像什么？引导幼儿编儿歌:左下半圆d d d、竖弯加横t t t 。 2、 学习语境儿歌d t,在儿歌里寻找带d t的字宝宝。 3、瞧课件寻找带d t的图片。 (五)扩展放松: 1、教师书写d t笔顺、使幼儿认清d t的笔画及笔顺。认准它们在拼音四线格中的位置。 2、幼儿描红书写教师指导。 声母d、t与单韵母拼读 一、活动目标: 1、正确认读d、t的发音。 2、运用“两拼法”示意图学习d、t与单韵母组成的音节、 3、运用课件及图片激发幼儿拼读的兴趣。 二、活动准备: 教具准备:拼音课件、光盘、字卡 学具准备:幼儿用书与铅笔。 三、活动过程: (一)激发兴趣 复习儿歌:左下半圆d d d、竖弯加横t t t 。引发幼儿学习兴趣 (二)指导认知 1、以抽卡片的形式复习带调的单韵母 2、以笔顺的形式让幼儿区别学过的声母d、t 3、语境儿歌复习单韵母及生母的声与型。 4、回忆生活中还有那些字宝宝带有的声音？ 5、瞧课件丰富对d t 的音节的认识。 6、出示音节:尝试拼读。引导幼儿感悟音节拼读的方法;声母短而快、韵母响而长。 如:d ——a——da d——e——de d——i——di d——u——du 综合实验（二）（——生活污水处理系统实验） 实验方案 姓名： 学号： 班级： 实验时间： 一、实验目的： 1、掌握污水生化处理实验设计的一般方法； 2、掌握各处理工序的基本原理； 3、掌握根据不同出水水质指标要求所控制的运行条件及控制方法 4、了解对整套废水处理系统运行的调试、运行、控制方法； 5、要求掌握的技能和知识点：水处理实验方案的编制要点，浊度仪、pH计、溶解氧仪等的正确使用和操作；取样方法；实验数据记录、整理和分析方法。 二、实验原理： 初沉池： 初沉池可除去废水中的可沉物和漂浮物。废水经初沉后，约可去除可沉物、油脂和漂浮物的50%、BOD的20%，按去除单位质量BOD或固体物计算，初沉池是经济上最为节省的净化步骤，对于生活污水和悬浮物较高的工业污水均易采用初沉池预处理。 A2/O原理： 生物池通过曝气装置、推进器(厌氧段和缺氧段)及回流渠道的布置分成厌氧段、缺氧段、好氧段。在该工艺流程内，BOD5、SS和以各种形式存在的氮和磷将一一被去除。A2O生物脱氮除磷系统的活性污泥中，菌群主要由硝化菌和反硝化菌、聚磷菌组成。在好氧段，硝 化细菌将入流中的氨氮及有机氮氨化成的氨氮，通过生物硝化作用，转化成硝酸盐；在缺氧段，反硝化细菌将内回流带入的硝酸盐通过生物反硝化作用，转化成氮气逸入到大气中，从而达到脱氮的目的；在厌氧段，聚磷菌释放磷，并吸收低级脂肪酸等易降解的有机物；而在好氧段，聚磷菌超量吸收磷，并通过剩余污泥的排放，将磷除去。 A2O法又称AAO法，是英文Anaerobic-Anoxic-Oxic第一个字母的简称（厌氧-缺氧-好氧法），是一种常用的污水处理工艺，可用于二级污水处理或三级污水处理，以及中水回用，具有良好的脱氮除磷效果。 该法是20世纪70年代，由美国的一些专家在AO法脱氮工艺基础上开发的。 工艺流程 二次沉淀池 工程中常简称：二沉池 接纳废水二级处理的出水，用以去除生物悬浮固体的沉淀池。在 大米销售合同范本 篇一：大米购销合同 大米购销合同 甲方：重庆市九龙山米业有限责任公司 乙方：开县黄桷树食品超市 甲、乙双方本着平等、互惠、互利、共同发展的原则，就大米购销事宜达成如下协议： 一、合同期限自XX年8月29日起至XX年8月28日止； 二、产品名称：品种和数量、单价、规格、型号 1、产品名称：大米（籼米）； 2、品种：九龙山大米 3、单价：暂定元/kg ，以后每季度随市场行情变化而变化。 4、规格型号：5kg/ 袋/ 、10kg/ 袋、25kg/ 袋 5、产品数量：依据实际数量 三、产品的等级、质量、标准和检验方法产品的等级：一级， 保证袋装大米符合国家标准 GB1354-XX如果是农户供应的散装大米，保证大米无农药、无污染、优质、安全、卫生。 四、产品送货标准 甲方提供小样品两份，每袋5kg ，双方认可后签字封存， 双方各持一份样品，乙方凭样品收货 五、结算方式：甲方货物经乙方管理人员验收、安全质量合 格、数量金额无误后，双方当事人签字确认乙方法人代表签字后以转账或现金方式付款。 六、包装形式：编织袋，5kg/ 袋、10kg/ 袋、25kg/ 袋 七、交货地点：开县黄桷树超市 八、交货时间：双方约定时间送货； 九、运输方式：甲方用专用安全卫生运输车送货至乙方指定地点； 十、违约责任：甲乙双方任何一方违约，违约方应赔偿另一方因违约造成的一切经济损失。 十一、甲、乙双方从签字之日起生效，甲乙双方各执一份，具有同等法律效力。 甲方代表签字：乙方代表签字： XX年8月29日 篇二：大米销售合同绥化华天米业有限公司大米购销合同 甲方：绥化华天米业有限公司 乙方： 经甲、乙双方友好协商，自愿签订购销合同，就甲方出 售给乙方商品达成如下协议： 一、产品名称：。 二、质量标准：。 三、数量：吨。 四、价格：元/ 斤。 声母d、t教案 2、课中操。念儿歌： fó fó fó, 我有一尊大肚 fó， 圆圆脑门圆肚皮， 成天乐得笑呵呵。（边做动作边念。） 3、教学f的发音，认清形。 （1）听示范，发音要领：上牙轻轻地放在下唇上，摩擦一下发出音。 （2）读，学生跟读，教师正音。 （3）记忆形：谁能记住f的字形。（伞柄、拐杖）教口诀：伞柄朝上 f f f （4）指导书写。两笔写成，学生书空。 4、教学f和单韵母的拼音。 a：f—ā→fā（发现）；f—á→fá（缺乏、惩罚）；f—ǎ→fǎ（法国）；f—à→fà（头发） o： f—ò→fò（佛像） u：f—ū→fū（皮肤、夫人）；f—ú→fú（福气、符号）；f—ǔ→fǔ（抚摸、辅助）；f—ù→fù（父亲、附加） （二）教学声母d 1、师引出：鼓声“咚”的声母就是d，板书：d。 2、教学d的发音，记清形。 （1）听：教师示范发音，舌尖顶住上颚，堵住气流，然后舌尖突然离开，让气流冲出来。 （2）看：教师范读时的口形，发音部位。 （3）读：领读，齐读，正音。 （4）记：马蹄声响 d d d 像个反6 d d d 左下半圆 d d d 3、教学d的书写。 （1）范写：两笔写成，半圆也在2楼。 （2）书空：作业本上写三个。 4、教学d与单韵母组成的音节。 a：d—ā→dā（搭车、答应）；d—á→dá（回答、达到）；d—ǎ→dǎ（打架）；d—à→dà（大树） e: d—é→dé(得到、品德) i：d—ī→dī（低头、水滴）；d—í→dí（敌人、笛子）；d—ǐ→dǐ（抵达、底下）；d—ì→dì（地板） u：d—ū→dū（首都、监督）；d—ú→dú（读书、单独）；d—ǔ→dǔ（打赌）；d—ù→dù（肚子）（三）教学声母t 1、今天我们要学的第二个声母“t”的样子就像一把弯弯的伞柄。板书：t，将雨伞打开，伞面张开后，在伞柄上加一横，就是t了。 2、教学t的发音，记清形。 （1）看、听：用薄纸放在嘴前，示范d t的区别。（发t时，嘴里有一股气送出。）p、t一样。（2）读、记：领读、轮读、正音。顺口溜记：伞柄朝下t t t。 3、指导t的书写。 4、拼读t与单韵母组成的音节。 a：t—ā→tā（他们、倒塌）；t—ǎ→tǎ（宝塔）；t—à→tà（踏步） e: t—è→tè(特别) i：t—ī→tī（踢球、梯子）；t—í→tí（题目）；t—ǐ→tǐ（身体）；t—ì→tì（代替、鼻涕） u：t—ū→tū（突出、凹凸）；t—ú→tú（图片）；t—ǔ→tǔ（泥土）；t—ù→tù（兔子） 三、巩固练习 1、默写6个单韵母 2、给下列加横线的字注音 大米购销合同 售方：_ _________________ 合同编号： 购方：______________________ 签定地点： 签定时间： 一．产品名称/产品等级/产品包装/产地年份/数量/总金额： 二．质量要求/技术标准：符合GB1354-2009标准(大米中的名贵品种、杂交品种、中熟米和陆稻米以及其他特殊品种，由省、自治区、直辖市另订标准或按质量分别归属）。 三．交（提）货时间/地点/方式：2016年月日前全部货物从发运站装车发出，2016年月底前发到购方指定的目的站或目的地仓库：。发/到货日期以铁路货票或汽运单据印章的日期为准（运单收货人为售方，待购方按合同规定向售方付清全部货款后，售方将货权移交给购方） 四．运输方式及计费方法：铁路棚车运输。铁路棚车内交货。或者汽车运输，购方指定目的地仓库交货。到站后的一切费用由购方承担。 五．交货数量/合理损耗：允许分批交货。每批交货数量以该批货物的运单标注的数量为准。如货物在到达目的站时发现/出现较大的质量、数量问题，购方应通知售方人员到场共同商议处理方法。 六．验收方法及提出异议期限：质量如不符合本合同规定，购方在货到目的站5日内提出，并在15日内向售方补交由国家质检部门出具的检验报告作为凭证。在目的站/仓库提取检验的样品（每批货物不少于2份）将保留在质检人处。 七．结算方式及期限：合同签订后购方须向售方预付合同总额的50%货款，在每批货物到达本合同指定的目的站或目的地仓库后两个工作日内向售方付清该批货物的全部余款。每迟付壹日购方须另向售方支付该批货款总额0.5%的罚金，直至购方向售方付清全部货款。售方在收款后10个工作日内向购方开具增值税发票。 八．本合同在执行中如遇不可抗力的情况发生，双方协商解决。 九．违约责任：按合同法。如本合同在执行中出现问题，双方协商不成，须提请法院裁决。 十．其他约定事项：1、本合同在执行中，如遇产品数量、质量出现问题，购方不得以此作为拒付售方货款的理由。有关问题如应售方负责，购方可凭有效文件及按本合同第六条规定，另行向售方提出索赔。2、每批货物 绿色食品大米（NY/T419-2006） 中华人民共和国农业行业标准 NY/T419-2006 绿色食品大米 Green food – Rice 农业部2006-01-26发布2006-04-01实施 前言 本标准代替NY/T 419—2000《绿色食品大米》。 本标准与NY/T 419-2000《绿色食品大米》相比主要修改如下： ——删除了3 定义； ——删除5.2稻谷的碾米品质指标； ——删除5.3外观品质指标； ——修订了5.4蒸煮和营养品质指标 ——修订了5.5加工质量指标，其中黄米改为黄粒米； ——删除了甲拌磷、对硫磷、氯化苦、二硫化碳限量指标； ——增加了毒死蜱、甲基毒死蜱、三唑磷、甲胺磷、溴氰菊酯、溴甲烷、七氯、艾氏剂、狄氏剂指标的限量。 本标准由中华人民共和国农业部提出。 本标准由中国绿色食品发展中心归口。 本标准起草单位：农业部食品质量监督检验测试中心（佳木斯）。 本标准主要起草人：王南云、杜欣谊、韩国、卢宝华、牛兆红、贺显书、杨梅岩。 绿色食品大米 1 范围 本标准规定了绿色食品大米的分类、要求、试验方法、检验规则、标志、标签、包装、运输和贮存。 本标准适用于绿色食品大米。 2 规范性引用文件 下列文件中的条款通过本标准的引用而成为本标准的条款。凡是注日期的引用文件，其随后所有的修改单（不包括勘误的内容）或修订版均不适用于本标准，然而，鼓励根据本标准达成协议的各方研究是否可使用这些文件的最新版本。凡是不注日期的引用文件，其最新版本适用于本标准。 GB 191 包装储运图示标志 GB/T 5009.11 食品中总砷及无机砷的测定 GB/T 5009.12 食品中铅的测定 GB/T 5009.15 食品中镉的测定 GB/T 5009.17 食品中总汞及有机汞的测定 GB/T 5009.18 食品中氟的测定 GB/T 5009.19 食品中六六六、滴滴涕残留量的测定 泥泵房水位标高为301.85m，闭水试验用水量约为2746m3，沉降观测点标高在闭水试验的前一天进行测量。 10贮泥池1 建筑面积约为170㎡，池底标高为299.70m，工艺设计试水水位标高为303.70m，闭水试验用水量约为620m3，沉降观测点标高在闭水试验的前一天进行测量。 4、编制依据：《给排水构筑物施工及验收规范》（GBJ114-90）。 二、主要材料及要求 1、大功率潜水泵、胶管：要用于闭水试验时抽水用； 2、标尺：主要用于观察充水时水位变化情况； 3、刻度尺； 4、水位测针：由针体和针头两部分构成； 5、百分表； 6、电流表。 三.闭水试验应具备条件 1、水池闭水试验应在下列条件下进行： 1）池体的混凝土达到100%设计强度； 2）现浇钢筋混凝土水池的防水层、防腐层施工以及回填土以前； 3）装配式预应力混凝土水池施加预应力以后，保护层喷涂以前； 2、水池闭水试验前，应做好下列准备工作： 1）将池内清理干净，修补池内外的缺陷，临时封堵预留孔洞、预埋管口及进出水口等； 2）检查充水及排水闸门，不渗漏； 3）设置水位观测标尺； 4）标定水位测针； 5）准备现场测定蒸发量的设备； 6）充水的水源应采用清水并做好充水和放水系统的设施。 3、水池闭水试验前，应做好下列检查工作： 1)外观质量检查合格； 2)构筑物内清理完毕,无杂物积水现象； 3)全部预留孔洞封堵不得漏水，位于水池底板以下的管道应封堵坚固不得漏水，堵板承载力 经核算并大于水压力； 4)闭水试验所需材料设备进场,人员到位； 5）试验脚手架搭设完毕，并符合安全规定。 四.闭水试验程序 施工准备----清理检查内壁-----封堵预留洞口-----注水浸泡------检查外壁及预留洞口渗水情况 ------验收------缓慢放水 五、闭水试验方法 根据设计要求每个构筑物都必须在其主体结构混凝土达到100%设计强度后，并在防水层及防腐层施工前进行满水试验，用以考核检验污水处理构筑物的渗水量是否达到标准要求，以免污水渗漏，再次污染环境，而且也避免钢筋混凝土结构内钢筋遭受腐蚀，影响结构安全。这期间应注意闭水试验必须用清水(切忌用污水)，逐池缓慢地放水试验，发现渗漏点要做好标记。试水水位应放至正常使用的最高水位，经三个昼夜的观察、记录，无渗漏再逐步放水。 1、准备工作 充水之前首先将池内清理干净，以免充水后池内浮渣漂浮水面，影响测试精度。池内外缺陷要修补平整，对于预留孔洞，预埋管口及进出口等都要加以临时封堵，同时还必须严格检查充水及排水闸口，不得有渗漏现象发生，在完成上述工作后即可设置充水水位观测标尺，用以观察充水时水位所达到的深度，水位观测标尺可以用立于水池中部的塔尺，也可在池壁内侧弹线标注标高控制线，接下来就是做好充水和放水系统的准备，搭设测试平台及出入水池的人行通道。 2、充水 1）向水池内充水宜分三次进行：第一次充水为设计水深的1/3；第二次充水为设计水深的2/3；第三次充水至设计水深。对大、中型水池，可先充水至池壁底部的施工缝以上，检查底板的抗渗质量，当无明显渗漏时，再继续充水至第一次充水深度。 2）充水时的水位上升速度不宜超过2m/d。相邻两次充水的间隔时间，不应小于24h。 3）每次充水宜测读24h的水位下降值，计算渗水量，在充水过程中和充水以后，应对水池 汉语拼音d 教案 一 -教学目标： 1、复习巩固单韵母及标声调的单韵母的读法。 2、学会d 这个声母，能读准音，记清形，正确书写。 3、学会d与单韵母a、u相拼。 4、能够用d与单韵母相拼的音节练习组词或说话。 教学重点： 学会d 这个声母，能读准音，记清形，正确书写。 教学难点： 1、学会dg与单韵母a、u的拼读。 2、用与音节相应的汉字组词或说话。 活动准备： 拼音卡片、图片 教学过程： 一、谈话导入。 （1）老师：小朋友们好，又到了学习汉语拼音的时候了，我们再一起去漫游拼音王国，好吗？ 老师：那就让我们乘上这“快乐列车”出发吧！“小小火车开起来，轰隆轰隆，呜……” （2）老师：啊，我们到了。瞧，拼音王国朋友们已经在这里欢迎我们了。我们来和他们打个招呼吧。 二、读读练练（复习已学的单韵母和声母）。 （1）请同学们读一读单韵母。 （2）老师：呀，这几个朋友有一个共同的名称你们还记得吗？谁来告诉大家？（他们叫单韵母）单韵母有几个？（单韵母有６个）哪6个？（a、o、e、i、u、u） （3）小朋友真聪明，现在这些单韵母朋友已经戴好帽子排好队了，我们一起来点点名吧。（读带调的单韵母） （４）老师：小朋友们读得真好！再让我们一起坐上火车去请出我们的声母朋友吧！（出示已学的声母b、p、m、f小朋友们读一读） （５）老师：小朋友们真不错，记住了我们已学的声母朋友。今天老师又给你们带来了一位新的声母朋友，他究竟是谁呢？我们一起来认识他吧！ 二、学习声母d： 谈话过渡：听说拼音乐园正在举行一场有趣的游园活动，让我们去瞧瞧。（课件出现一马正在河边草地上跑情景图） １、看图，提示：你看到了什么？把你看到的情景告诉大家。马跑的声音是怎么样的？听声dedede，我们今天要认识的声母d，就藏在图中，你能找出来吗？（点击d从中拖出并闪烁） 2、教学d的发音。过渡；瞧，多么可爱的拼音朋友，你能向他打个招呼吗？ ⑴、学生尝试发音。 ⑵、教师范读，讲解发音要领，学生仔细观察。 ⑶、让学生自己感受舌尖的变化。 ⑷、领读，齐读，同桌互读，开火车读。 ３、辨别“d-b”的形。 幼儿园大班拼音教案：声母d、t的学习 (一)复习检查。 1、卡片认读声母：b p m f，这些字母我们称它们什么?(声母)声母一般都站在音节的最前面。 2、认读韵母卡片，这些字母我们称它们为什么?(单韵母)再人带调韵母，教师讲解：声调都标在韵母上面。 3、复习带调音节bá pá bà mā mù bù mǒ等。 4、认读生字和词语：爸、妈、我、爸爸、妈妈 (二)导入新课。 这节课，我们要学习两个声母和它们的拼音。比一比，看哪个小朋友最认真，最聪明，学得最好，读得最准。 (三)教学声母d。 1、看投影说话引出d：图上画了什么?它会发出什么声音?说话：鼓棒敲鼓，咚咚咚。 师引出：鼓声“咚”的声母就是d，板书：d。 2、教学d的发音，记清形。 (1)听：教师示范发音，舌尖顶住上颚，堵住气流，然后舌尖突然离开，让气流冲出来。 (2)看：教师范读时的口形，发音部位。 (3)读：领读，齐读，正音。 (4)记：马蹄声响 d d d 像个反6 d d d 左下半圆 d d d 3、教学d的书写。 (1)范写：两笔写成，半圆也在2楼。 (2)书空：作业本上写三个。 4、教学d与单韵母组成的音节。 (1)板书d，声母是→d。板书ì，韵母是→ì。声音不中断，紧接着带出ì，直呼→dì。板书：dì。 (2)开火车读di的四声，组词读。 (四)做课中操。 (五)教学声母t。 1、出示雨伞，引出t：请同学看弯弯的伞柄，今天我们要学的第二个声母“t”的样子就像一把弯弯的伞柄。板书：t，将雨伞打开，伞面张开后，在伞柄上加一横，就是t了。 2、教学t的发音，记清形。 (1)看、听：用薄纸放在嘴前，示范d t的区别。(发t时，嘴里有一股气送出。)p、t一样。 (2)读、记：领读、轮读、正音。顺口溜记：伞柄朝下t t t。 3、指导t的书写。 4、拼读t与单韵母组成的音节。 (1) t---ī---tī谁会读?t---ū---tū? (2)拼读ta te ti tu及四声连读。 (六)巩固复习。 1、卡片读d t。 2、对比读：b---p---d f---t (念顺口溜，做动作强化记忆。) 3、看实物猜字母。 拿一把小花伞，伞柄朝上，(f)，伞柄朝下，(t)，学生读字母。 形近声母b、p、d、q的教学设计 形近声母b、p、d、q的教学设计 使用教材：义务教育课程标准实验教科书语文一年级上册（语文出版社s 版） 一、教学目标 1、认知目标：学会声母b、p、d、q能够读准音，认清形。 2、能力目标：（1）能根据图意说简单的话，掌握声韵拼读方法，正确拼读b、p、d、q与单韵母a.o.e.i.u.ü组成的音节。 （2）会读bó bo pá po dǎbǎ dīdā 课本中出现的这四个音节词。 二、内容分析及说明 我依据我的教学经验和学生心里发展情况好动容易遗忘特点，充分利用教材资源，做出一个教学设想打破教学常规向拼音教学挑战，把学生易混淆的形近声母b、p、d、q整合在一个课时多渠道，学拼单，进行教学。玩中学，学中悟，让学生真正掌握区分这四个声母。 本课时分四部分，第一部分情境图，第二部分声母b、p、d、q读准音，认清形。第三部分拼读b、p、d、q与单韵母a.o.e.i.u.ü组成的音节，第四部分：区别记忆b、p、d、q，为了更好记忆区分这四个声母的儿歌和手势，本课时没安排书写，书写将在第二课时进行。 第一课时 一、复习巩固，激趣导入： 1、师：小朋友，看看老师今天给你们带来了什么？（出示写有6个单韵母的窗花剪纸卡片）谁读的好，老师就奖给谁？ （指名一人读，其它人齐读） 2、师：这6个单韵母拼音宝宝，小朋友，读得准确、洪亮。为了奖励你们老师给大家带来了一幅漂亮的图画，（课件出示课本8页2、3图），请小朋友们仔细观察，（1）这是什么地方？（2）图上都有谁？他们都在干什么？ （师相机板书音节bó bo pápó）用彩色粉画出b、p。 师：小朋友看一看这两个拼音宝宝我们学过吗？（学生回答）这就是我们这节课要认识的新拼音宝宝，声母b和p，板书：声母b.p。 声母d的教学 Revised by Hanlin on 10 January 2021 认识 d 教学目的: 1、学会声母d，读准音，认清形，正确书写。 2、学会声母d和单韵母的拼读，及带声调的拼读音节。 教学准备: 1、声母d的字母卡片。 2、声母d与单韵母相拼的卡片。 3、“摘苹果”的游戏挂图。 教学过程: 1、导入:(齐读6个单韵母和学过的声母b，p，m，f 复习) 2、老师:“看，今天，老师给小朋友带来了什么?”幼儿:(一匹马) 师:马在做什么动作呢? 幼:奔跑。 老师:那，马奔跑会发出什么声音呢请小朋友想一想来回答老师的问题 幼儿:“的，的，的 d d d ” 3、老师接着编出顺口溜:马蹄印子d d d 4、老师先读，幼儿跟读。(马蹄印子d d d) 5、老师一下子惊讶的表情:小朋友想一想，谁最聪明能想出d和我们学过的什么拼音相像呢? 幼儿踊跃的举手，( b---d ) 右下半圆b b b ，左下半圆d d d 师:1、“好，我们一起读。” 2、老师读前一句，幼儿读后一句。 6、书写格式: d有两笔写成，第一笔: 弯，第二笔:竖。 d写在第一格和第二格。 7、情境游戏。 A、出示挂图，一棵苹果树，树上有若干个大苹果(苹果里有声母d ，还有韵母a，i，e，u) B、请小朋友先单独指读，接着声母和韵母拼读。 C、“哇，好大的苹果呀，我们来做个摘苹果的游戏吧，看谁读得对，谁就把老师的苹果摘走。” D、请若干个小朋友来表演。 8、最后，请小朋友拿本字练一练。 教学反思 1、幼儿拼音教学要生活化，情境化。 2、以游戏和活动为主线，让幼儿动口，动脑，动手的多种感官协同参与。 3、创设生动有趣的情境，是提高幼儿学习拼音兴趣之有效的方法。在教学中，我感受到了“情境式”的教学模式，不仅适用于拼音教学，还能适用于算术思维教学和识字教学。这样，幼儿就能开心地“玩中学”。 **********工程 污水处理池满水试验方案 建设单位：***** 监理单位：*****工程咨询有限公司 施工单位：*****环保工程有限公司 编制日期：2015-2-25 污水处理池满水试验方案 一、工程概况 **********工程污水治理工程，按照施工验收规范要求，水池需进行满水试验。 污水处理工程所有水池均为有盖式矩形地埋式结构，池内空净尺寸分别为：处理池26.65×7.4×4.5米，设计蓄水深度3.7m，池底标高-5.0m，池顶标高-0.3m，有效蓄水量729.68m3；调节池、事故池30.1×7.4×5.3米，设计蓄水深度3.0m，池底标高-6.0m，池顶标高-0.50m，有效蓄水量668.22m3。 二、试验方案 试验用水要求使用清洁的自来水或地下水，以避免污染水池池壁，影响池壁抹灰及防水等下工序质量。经与甲方协调，根据工程情况，试验用水从厂区车间用水引入，分3次进行，每次连续注水不超过1/3。注水深度分别为处理池每次不超过1.25m、调节池事故池每次不超过1.0m。分别满足设计要求最高水位3.7m和3m。 按照规范要求，冲水的水位上升速度每天不得超过2米，同一池相邻两次注水间隔时间不小于24小时。水位超过施工缝和每次注水停止作为观察重点。注水到设计水面按照规范进行水池渗水量测量和计算，同时进行沉降观察。 三、试验程序 试验准备第一次注水观察记录第二次注水观察记录注水到设计水位沉降观察放、排水防腐装修 四、准备工作 1. 组织准备： 组建成立满水试验领导小组，试验小组全过程受甲方监理监督和核验。组长由项目经理担任，技术负责人担任副组长，组员有测量员、实验员、记录员和电工组成，配合工人2名。 2. 现场准备： （1）安装从临时水井至水池的管道，将水源引至水池内。 （2）池体混凝土达到设计强度后，防腐、装修和回填土之前，将池内清理干净，修补池内外的缺陷。临时封堵预留孔洞、预埋管口及进出水口等，并检查充水及排水闸门，不得渗漏。 （3）设置水位观测标尺。 （4）水池的预埋管与外部管道连接时，跨越基坑的管下填土应压实。 （5）布置好现场水池之间调水和排放水的水泵、管道、出口位置等设备、机具、材料。 3.物资准备： （1）水源：采用洁净的车间生产用水，每天用水量为466m3，按10%备用损耗水量，总备用水量约每天513m3。 （2）水泵：采用潜水式污水泵，水泵流量≥35m3/h，水泵功率5.5kw，数量2台，两座水池各使用一台。 （3）管道：管径DN100承压塑料管或钢管，长度160m；DN100软管10m。配套跨越基坑等架空管道支架。 （4）电气：开关箱20A，2台；铜芯电缆3×4+2.5，200米；碘钨灯 2.1.1 早籼米、籼糯米质量指标见表 1。 大米检验标准 GB 1354 — 86 本标准适用于收购、销售、调拨、储存、加工和岀口的商品大米。 1分类 1.1根据稻谷的分类方法分为三类: 1.1.1 籼米：用籼型非糯性稻谷制成的米。米粒一般呈长椭圆形或细长形。按其粒质和籼稻 收获季节分为以 下两种: 早籼米：腹白较大，硬质颗粒较少。 晚籼米：腹白较小，硬质颗粒较多。 1.1.2 粳米：用粳型非糯性稻谷制成的米。米粒一般呈椭圆形。按其粒质和粳稻收获季节分 为以下两种: 早粳米：腹白较大，硬质颗粒较少。 晚粳米：腹白较小，硬质颗粒较多。 1.1.3 糯米：用糯性稻谷制成的米。按其粒形分为以下两种: 籼糯米：用籼型糯性稻谷制成的米。米粒一般呈长椭圆形或细长形，乳白色，不透明；也有 的呈半透明状（俗称阴糯），粘性大。 粳糯米：用粳型糯性稻谷制成的米。米粒一般呈椭圆形，乳白色，不透明；也有呈半透明状 （俗称阴糯），粘性大。 1.3大米中的名贵品种、杂交品种、中熟米和陆稻米以及其他特殊品种，由省、 辖市另订标准或按质量分别归属。 2质量标准 2.1各类大米按加工精度分等。等级指标及其他质量指标见表1.2各类大米中混有其他类大米的总限度为 5.0 %。 自治区、直 1、表 2、表 3、表4。 2.1.2 晚灿米质量指标见表 2。 等级 加工精度 按实物标准样 最大限度杂质 碎米，％ 特等 对照检验留皮 程度 按实物标准样 标准 一等 对照检验留皮 程度 标准 按实物标准样 对照检验留皮 二等 程度 按实物标准样 标准 三等 对照检验留皮 程度 不完善 3.0 4.0 6.0 8.0 总量 其中: 矿物 0.25 0.30 0.40 0.45 色泽 水分 糠粉％ 质，％ 0.15 0.02 0.20 0.02 0.20 0.02 0.20 0.02 带壳稗 粒/kg 20 50 70 90 稻谷粒 粒/kg 总量 12 16 20 35.0 气味 其中: 小碎 2.5 14.0 口味 正常 鉴于目前的市场情况分析了解，从区域和档次两个方面对大米市场进行细分。 一、按区域分类 把大米产品定位于国内市场，同时国内市场又分为华南，华北，华东，华中，东北，西南，西北七大区域。 二、按档次分类 1、低档米市场整个市场充斥着低档大米，因为各个企业不用研发就能生产低档大米。从商超这个渠道来看，竞争最大，基本上各地区的商超里的低档订单，都在第一时间被抢走。低档大米的售价，平均在23元左右。 2、中档米市场中档米在研发上要投入一些资金，竞争比较激烈。而且中端市场的需求量也很大，在招投标中，有许多中端市场的订单。 3、高端市场高端米需要全部研发，所以很少会有人在第一年全部投入，这是一块大蛋糕，应该在第一年取得尽可能多的高端订单。 三、现实生活中的大米市场 1、中高档米市场。散装零售价位在每公斤6元以上主流价格带在每公斤6-12元有机大米售价每公斤18元抗疲劳的功能大米每公斤36元总体来看，每公斤10元以上的高价米在商超销售的销售总额的占比不到1% 最高端米市场一般诉求点：有机。 2、小包装米市场。主要是中高档品牌的包装米。有1公斤，2.5公斤，5公斤，10公斤，15公斤等等。有机大米和绿色大米一般以小包装米形式进行销售，而小包装米不一定就是有机大米和绿色大米。小包装米市场和中高档米的市场重叠。 3、有机米。有机大米是衡量大米质量标准的一个最高等级，也是无公害大米和绿色大米。所谓有机大米是在种植、收割、储藏、加工、包装等一系列过程中，有严格要求的国家标准，不允许使用任何化学合成的药物激素和对人体有害的化学物质，可以说是食品安全最高等级的大米。在栽种稻米的过程中，使用天然有机的栽种方式，完全采用自然农耕法，使用的肥料一定要是有机肥，而且种植的土壤政府有规定，要有三年都没有碰到一点化学农药，这样子做可以完全消除稻米内可能有的重金属，或者是毒素，可以达到完全没有污染的效果。 4、有机大米和绿色大米的区别绿色食品和有机食品虽然都是以环保、安全、健康为目标的可持续食品，代表着未来食品发展的方向，但是绿色食品和有机食品又有一定的区别。其中最重要的一个区别就是有机食品的标准比绿色食品高，被人称为“纯而又纯”的食品，它从基地到生产，从加工至上市都有着严格的要求。首先，有机食品在其生产和加工过程中绝对禁止使用农药、化肥、激素、转基因等人工合成物质，而绿色食品则允许有限制地使用这些物质。其次，有机食品的生产和加工要比绿色食品严格得多。最后，有机食品的生产和加工要比其他食品难得多，管理也严格得多。有机大米一般同时通过绿色大米认证。而绿色大米则不一定能通过有机大米认证。普通消费者，则没有把绿色大米和有机大米严格区分开。也对于有机大米认证和绿色大米认证不是很了解，普遍关注大米产地和大米品种。 中国七大区域中，华南，华北，华东的市场需求及人口数会相对大于华中，东北，西南及西北地区，且人均消费水平较高，中高档次产品接受度高。而华中，东北，西南及西北地区的人均消费水平较低，对高档大米接受度较低。 通过以上的市场分析，把产品定位如下： 1、在公司发展的三年内，驻足于国内市场的发展 2、三年内，先做华中，东北，西南及西北地区市场，在公司有初步的经营利润后，再利用公司利润提升产品档次，做华南，华北，华东区域 污水处理实验报告三篇 第1条 污水处理实验报告水处理实验报告名称沉淀管烘箱平衡曝气充氧装置恒温振荡器722分光光度计过滤和反冲洗装置ZR2-6混凝搅拌器型号规格备注水泵漏斗容量瓶移液管滴定管1/10000分析平衡空气压缩机课堂评分60测试结果实验报告评分40总分，水处理实验报告实验1自由沉降实验1实验目的1初步了解自由沉降颗粒的测试方法2进一步了解和掌握自由沉降的规律，根据测试结果绘制时间-沉降速率(te)-沉降速率(uE)和CT/c0 ~ u关系曲线。 第二个实验原理沉降指的是通过重力从液体中去除固体颗粒的过程。 根据液体中固体物质的浓度和性质，沉淀过程可分为四类:自由沉淀、絮凝沉淀、分层沉淀和压缩沉淀。 本实验旨在研究和探讨污水中非絮凝固体颗粒的自由沉淀规律。 如图所示，试验是用沉淀管进行的。 如果水深设置为h，颗粒的沉降速度u = h/t u = h/t可以在t 时间内下沉至h深度。 根据给定的时间t0，计算颗粒的沉降速度u0。 所有沉淀速度等于或大于u0的颗粒可在t0时完全去除。 如果原水悬浮物的浓度为c0(毫克/升)，则原水悬浮物的沉淀率为c0(毫克/升)。CT。经过T时间后，污水中剩余悬浮物的浓度(毫 克/升)h采样口高度(厘米)T采样时间(分钟)。公式中自由沉淀试验装置的三个实验装置和设备 1、沉降管、储水箱、水泵和搅拌装置 2、秒表、卷尺 3、用于测定悬浮物的设备分析天平、称重瓶、烘箱、滤纸、漏斗、漏斗架、量筒、烧杯等。 4、经水和高岭土处理的污水。 四个实验步骤1。将一定量的高岭土放入配水槽，启动搅拌机，充分搅拌。 2.取200毫升水样(测得的悬浮液浓度为c0)，确定取样管中取样口的位置。 3.启动水泵，将混合液打入沉降管至一定高度，停泵，停混合器，记录高度值。 启动秒表并开始记录建立时间。 4.时间为 当1 、3 、5 、10 、15 、20 、40 、60分钟时，分别从取样口抽取200毫升水，并测量悬浮物浓度(ct)。 5.每次取样时，应首先排出取样口中的积水，以减少误差。取样前后应测量沉淀管内液面至取样口的高度，并取两者的平均值进行计算。 6.在每个沉降时间测定水样的悬浮物浓度和固体含量。 首先，将烘箱调至105±1℃，将滤纸放入称量瓶中，打开盖子，将称量瓶放入105℃烘箱至恒重，称量重量，然后取出恒重滤纸， 经济观察报心力/文微信的朋友圈传播新知和谣言同样迅速。一篇名为《大米是垃圾食品之王》的文章，在朋友圈里拥有超过100万的阅读纪录，依据文中的观点，所谓的“现代营养学”看来，白米饭儿乎不含有蛋白质、脂肪、维生素、矿物质，只有淀粉，因此白米饭绝对符合垃圾食品的定义。 文章的科学性与否先不论证，有多少人因为这篇疯转的文章而远离米饭也未得而知，一个需要注意的事实是，作为超过半数以上中国人每日的主食，普通人对大米的研究与了解少得可怜。南米北面作为中国主食分野，饮食文化的完整与差异也大多在此框架内形成。主食的故事是有趣的边际话题，我们离土地越远，对食物就越多困惑。而千百年来的自然选择，乂留给我们什么样的影响？ 大米是垃圾食品？ “在美国，关于米和面孰优孰劣的争议其实一直存在，换句话说，针对大米的质疑从来 没有间断过。”张超在美国生活了许多年，刚到美国的时候，因为班上有泰国同学，大 家约着去吃泰国菜，一位美国同学鄙视地指着口米饭，“你们亚洲人怎么会喜欢吃这种 东西？白米饭最没有营养。”他说，一边取出自己带的燕麦酸奶一在营养学苛刻的数据 分析里，这玩意儿简直是“完美主食”，富含膳食纤维，还顺带促消化、刺激肠胃蠕 动，不让其他食材带来的脂肪在你体内囤积。 这是张超笫一次对自己二十儿年来仰赖的主食摄入产生怀疑。事实上，那些认为白米饭是垃圾食品的观点也有论据，在哈佛大学公共卫生学院营养学系的官网，根据食物营养与人体健康的关系，把日常食物排成了一座指导大众健康膳食的金字塔，分为“应该多吃”（金字塔底座）、“适量多吃”（第二层）、“适量少吃”（第三层）和“少吃或不吃”（金字塔顶尖）四大类。上面的确把口米饭放在“金字塔” 的塔尖，与红肉、加工肉类、牛油、含糖饮料、糖果、盐并列，认为应该少吃或不吃。而在20年前，同样是美国的膳食指南，大米还与面包谷物一起，被营养学家放在应该多吃的金字塔底座。 营养师刘纳看来，将大米完全妖魔化完全是断章取义，“首先需要明确一个概念, 我们现在所吃的，大部分是口米和精面，也就是经过精加工的大米与面粉，在我们营养学上，当劝导大家多吃杂粮的时候，会把这种大米作为一个反例，我们的确认为这种去皮去得很干净，磨得光滑漂亮的大米，提供了过多空洞的热量，而其他的营养成份只占到了36%。” 营养学的适用与否绝对是一个时代槪念。精米遭到排挤的同时，糙米得到了营养学家的一致追捧，它是指除了外壳之外都保留的全谷粒，含有皮层、糊粉层和胚芽的米，由于口感粗糙，质地紧密，煮起来也比较费时，在机械生产力欠发达，精米难得的年代，吃这种米被认为是贫穷的标志。糙米虽然不好吃，不过其中含有现代人的饮食中很缺乏的膳食纤维，还有相当多的维生素、矿物质，以及丰富的抗氧化剂。此外，还有含量不低的不饱和脂肪一看起来都是好东西，即使你并不了解这些名词的真正意义，也该在那些铺天盖地的食品广告里听过吧。 1 一月二月三月 产品名称数 量 金 额 利 润 产品 名称 数 量 金 额 利 润 产品 名称 数 量 金 额 利 润 合计 合 计 合 计 四月五月六月 产品名数 量 金 额 利 润 产 品 名 数 量 金 额 利 润 产 品 名 数 量 金 额 利 润 实验室实用手册 山东美泉环保科技有限公司 实验室 一、实验员守则 1、实验员必须严格遵守实验室的有关规定，按照试验程序进行操作。 2、详细的记录试验数据，注重试验的科学性，不得随意涂改与编造数据。 3、在试验中保持谨慎的态度，明确试验目的、内容与要求，做好实验记录。 4、及时了解新的实验方法和检测手段，提高工作效率。 5、了解药品的一般性质，合理选择和利用药品 6、注意实验室安全。了解和掌握一定的防火、防水、防爆知识，在离开实验室之前检查水电设施是否安全。 7、严禁在实验室内吃东西、吸烟等进行与实验无关的事情。 8、节约水、电及实验药品，不造成不必要的浪费。 9、保持实验室内环境卫生。 二、药品、试剂管理规则 1、将药品根据实验项目或同种盐类（如钾盐、钠盐、铵盐等）进行分分类整理，做好记录。 2、药品最好放在阴面通风的房间里，属于一般要求避光的，装在棕色瓶里即可；属于必须避光的，外层黑纸不要去掉。 3、剧毒或致癌物质（如汞盐、氰化钾、氧化砷、叠氮化合物等）及腐蚀性药品要放在保险柜内，非实验人员不得取用。 4、易燃或易挥发的溶剂不准用明火加热，可用水浴加热；不准在敞口容器中加热或蒸发；溶剂存放或使用地点距明火至3米以上。 5、某些强氧化剂如硝酸钾、硝酸铵、高氯酸（也属强腐蚀剂）、高氯酸钾（钠）、过硫酸盐等严禁与还原性物质如有机酸、木屑、硫化物糖类等接触。 6、药品取用要坚持“只出不进”的原则，以免污染药品。药品用完后放回原处，以便下次使用。 7、药品选用要根据用途，在分析监测中，除特殊规定外，一般选用分析纯。 8、试剂规格如下： 质量。 10、试液标签都应标明试液名称、浓度、配制日期、保存期限等。如发现试液有变色、沉淀、分解等,则应弃去重配。 11、试剂瓶的磨口塞必须与瓶口密合,以防杂质侵入和溶剂挥发。 12、碱性和浓盐类溶液勿贮于磨口塞玻璃瓶中，以免瓶塞与瓶口固结而不易打开，最好放在聚乙烯瓶中保存。遇光易变质的溶液应贮于棕色瓶中，暗处保存。废水处理实验方案
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