Exact Solutions of Low-Dimensional Reaction-Diffusion Systems

竹材浸渍用酚醛树脂的合成及表征王春霞1,赵磊2,刘浩阳1,张长武1*,张晶1(1.黑龙江省木材科学研究所,黑龙江哈尔滨150081;2.东北林业大学,黑龙江哈尔滨150040)摘要:介绍了采用蒸馏法及分光光度法测定竹材游离苯酚含量的方法。

实验选用氢氧化钠作催化剂,采用一次逐步加入甲醛的方法合成低游离酚的水溶性酚醛树脂。

采用单因子试验方法分析了反应温度为55℃时保温过程中游离苯酚含量的变化情况,反应原料摩尔比、催化剂用量、分次加甲醛量对合成酚醛树脂游离苯酚的影响,确定优选的合成工艺为:反应温度55℃;保温反应时间60min;F/P 摩尔比2.3;NaOH 用量0.4;初次加甲醛量50%。

关键词:酚醛树脂;低游离酚;重组竹;浸渍中图分类号:TS 652文献标识码:Ａ文章编号:2095-2953(2012)08-0014-03Synthesis and Characterization of Phenolic Resin for Bamboo ImpregnationWANG Chun-xia 1,ZHAO Lei 2,LIU Hao-yang 1,ZHANG Chang-wu 1*,ZHANG Jing 1(1.Heilongjiang Timber Science Research Institute,Harbin Heilongjiang 150081,China;2.Northeast Forestry University,Harbin Heilongjiang 150040,China)Abstract :A m e tho d for o bta ining free phe nol fro m re s in thro ugh dis tilla tio n a nd de te rm ining the co nte nt o f fre e phe no l by m e a ns of a s pe ctro pho to m eter is intro duced.In the e xpe rim e nt,s o dium hydro xide is us e d a s a cata lys t and fo rm a ldehyde is a dded g ra dua lly to s ynthetiz e w ater-s o luble phe no lic res in with lo w fre e phe no l.A s ing le fa cto r e xpe rim enta l m e thod isus ed to a na lyz e the cha nge in the co nte nt o f fre e phe no l in the ins ula tio n proce s s w he n the re a ction tem pe ra ture is 55℃a nd the e ffe ct of rea cta nt m o la r ra tio ,re a ctio n te m pe ra ture a nd fo rm a lde hyde co nte nt o n thefre e phe no l in the s ynthetic pheno lic re s in to dete rm ine the optim a l s ynthe s is pro ce s s :re a ctio n tem pe ra ture ,55℃;ins ula tio n rea ctio n tim e ,60m in;F/P Mo o re ra tio ,2.3;Na OH a m o unt ,0.4;Initia l a dditio n a m o unt o f form a lde hyde ,50%.Key words :phe no lic re s in;lowfre ephe nol;reco ns olida te d ba m bo o ;im preg nation我国地处世界竹子分布中心,是世界上竹类资源最丰富的国家,现有纯竹林面积420万hm 2,其中毛竹林300万hm 2,小径杂竹林120万hm 2。

CorrespondenceSubmissions should be made via our electronic submission system at /thelancet/3Awasthi S, Peto R, Read S, Clark S, Pande V, Bundy D. Vitamin A supplementation every 6 months with retinol in 1 million pre-school children in north India: DEVTA,a cluster-randomised trial. Lancet 2013; 381: 1469–77.4Fisker AB, Bale C, Rodrigues A, et al.High-dose vitamin A with vaccination after 6 months of age: a randomized trial. Pediatrics 2014; 134: e739–48.5Mason JB, Benn CS, Sachdev H, West KP Jr, Palmer AC, Sommer A. Should universal distribution of high dose vitamin A to children cease? BMJ 2018; 360: k927.6Benn CS, Martins C, Rodrigues A, et al. The effect of vitamin A supplementation administered with missing vaccines during national immunization days in Guinea-Bissau. Int J Epidemiol 2009; 38: 304–11.7Fisker AB, Aaby P, Bale C, et al. Does the effect of vitamin A supplements depend onvaccination status? An observational study from Guinea-Bissau. BMJ Open 2012; 2: e000448.8Andersen A, Fisker AB, Rodrigues A, et al. National immunization campaigns with oral polio vaccine reduce all-cause mortality: a natural experiment within sevenrandomized trials. Front Public Health 2018; 6: 13.effect can vary by vaccination status, and vitamin A supplementation might be harm f ul in certain subgroups. Perhaps we should deplore that OPV campaigns are being stopped if they are associated with improved survival,8 but there seems to be no reason to fear that reducing vitamin A supplementation coverage will decrease overall survival. Is it not time to spend sparse resources more wisely?We declare no competing interests.*Christine Stabell Benn,Ane Bærent Fisker, Frank T Wieringa, Anna Coutsoudis, H P S Sachdev*********Research Centre for Vitamins and Vaccines, Bandim Health Project, Statens Serum Institut,2300 Copenhagen, Denmark (CSB, ABF); Odense Patient Data Explorative Network, Institute of Clinical Research, Odense University Hospital,University of Southern Denmark, Odense, Denmark (CSB, ABF); Bandim Health Project, IndepthNetwork, Bissau, Guinea-Bissau (CSB, ABF); UMR-204 Nutripass, French National Research Institute for Sustainable Development, Montpellier, France (FTW); Department of Paediatrics and Child Health, University KwaZulu-Natal, Durban, South Africa (AC); and Sitaram Bhartia Institute of Science and Research, New Delhi, India (HPSS)1 The Lancet. Vitamin A distribution in danger. Lancet 2018; 391: 1866.2Beaton GH, Martorell R, Aronson KJ, et al. Effectiveness of vitamin A supplementation in the control of young child morbidity and mortality in developing countries. Nutrition policy discussion paper no. 13. Geneva: United Nations, Administrative Committee on Coordination, Subcommittee on Nutrition, 1993.Vitamin A distribution in danger: should we worry?In an editorial (May 12, p1866),1 The Lancet supported UNICEF ’s call for action to prevent a drop in high-dose vitamin A supplementation cov e r a ge as the important delivery vehicles, the nation a l oral polio vaccine (OPV) campaigns, are coming to an end. This is reason a ble if vitamin A supplementation is an important intervention—but is it?The policy to provide vitamin A sup-p l ement a tion twice per year to chil-dren aged 6–59 months was based on eight trials from the late 1980s and early 1990s.2 However, results of two recent trials 3,4 published in 2013 and 2014 showed no effect of vitamin A supp l ementation on overall survival, and there are other reasons to quest i on the continuation of vitamin A supplementation.5ew studies have assessed the effect of vitamin A supplementation campaigns on survival. In Guinea-Bissau, the effect of these campaigns depended on vaccination status (table). Vitamin A supplementation was as-sociated with survival benefits when given with or after measles vaccine, but not with or after diphtheria-tetanus-pertussis vaccine.6,7 In an assessment of national campaigns, OPV campaigns were associated with survival benefits (mortality rate ratio 0·81, 95% CI 0·68–0·95), but campaigns with OPV plus vitamin A supplementation or vitamin A supplementation alone had no effect, with a mortality rate ratio of 1·10 (0·82–1·48) for OPV plus vitamin A supplement a tion, and 1·04 (0·80–1·35) for vitamin A supplementation alone.8To our knowledge, no other recent study has assessed the effect of vitamin A supplementation cam-paigns on survival. Therefore, the avail a ble data suggest that vitamin A supplemen-tation campaigns nowadays have no overall effect, theIn an editorial,1 the Editors lament the fact that vitamin A distribution has reached a 6-year low, according to a UNICEF report. However, vitamin A supplementation was never intended to be a long-term sustainable strategy, as reminded by Michael Latham,2 who called attention to the “great vitamin A fiasco” in 2010.Although the cost-effectiveness of vitamin A supplementation has been demonstrated in controlled trials, itsCorrespondencefield effectiveness is dependent on a regular distribution system. Moreover, more than one capsule yearly is needed. In Niger, we showed that the prevalence of low serum retinol among weaned children aged 2 years was nearly back to presupplementation levels only 3 months after vitamin A capsules were given (39·8% of children before supplementation, and 34·4% after 3 months; unpublished data).F ood-based measures are indeed imperative for sustained control of this deficiency. What is unique about vitamin A deficiency is that food solutions exist and are feasible, even in low-income populations. Some 20 years ago, Noel W Solomons3 concluded that red (unrefined) palm oil, the highest and most bioavailable plant source of provitamin A, did as well as vitamin A supplements. Red palm oil could do the work in most of sub-Saharan Africa, provided that it is not bleached during cooking and an efficient commercial distribution network is established. Our studies in non-producing areas of Burkina Faso showed that people were willing to buy red palm oil and that it was effective in significantly curbing vitamin A deficiency in mothers and children (before-and-after differ-ence in proportion of patients with deficiency: p<0·01 in children and p<0·001 in mothers).4,5 What is needed is the scaling-up of such relevant food-based interventions to take over from erratic vitamin A capsule distribution.I declare no competing interests.Hélène Delisle*************************** Department of Nutrition, Faculty of Medicine, University of Montreal, Montreal, QC H3C 3J7, Canada1 The Lancet. Vitamin A distribution in danger.Lancet 2018; 391: 1866.2 Latham M. The great vitamin A fiasco.World Nutr 2010; 1: 12–45.3 Solomons NW. Plant sources of vitamin A andhuman nutrition: red palm oil does the job.Nutr Rev 1998; 56: 309–22.4 Zagré NM, Delpeuch F, Traissac P, Delisle H.Red palm oil as a source of vitamin A formothers and children: impact of a pilotproject in Burkina Faso. Pub Health Nutr 2003;6: 733–42. 5 Delisle H. The nutritional value of red palm oil.In: Rival A (ed). Achieving sustainablecultivation of oil palm. Cambridge: Burleigh-Dodds Science Publishing, 2017: 217–31.Did Cro-Magnon 1 haveneurofibromatosistype 2?In their Correspondence to The Lancet(March 31, p1259),1 Philippe Charlierand colleagues infer that the Cro-Magnon 1 skull (Les Eyzies, F rance)had neurofibromatosis type 1 (NF1).Their diagnosis was based on a micro-CT scan examination and three-dimensional reconstruction of theskull, which permitted a detailedanalysis of the cranial fossil remains,including, in particular, the exactbone aspect of a round polycyclicosteolytic lesion on the right frontalbone (attributed to a progressive boneerosion secondary to a subcutaneousschwannoma) and the aspect and sizeof the cranial nerve foramina (showing“asymmetry of the size of the inter-nal auditory meatus” secondary to anacoustic schwannoma without ad-ditional foramina anomalies).1However, Charlier and colleaguesbased their diagnosis of NF1 on fea-tures belonging to the clinical andradiological phenotype of neuro-fibromatosis type 2 (NF2): indirectsigns of the presence of nodular(subcutaneous) schwannomas andschwannoma of the VIII cranial nerve.They stated that acoustic neurinomas(schwannomas) are more frequentin NF2, but have also been reportedin NF1 and that “cases of internalauditory meatus enlargement in NF1have also been described without anyassociated acoustic nerve tumour”. Wethink that, in this Cro-Magnon 1 skull,the diagnosis of NF1 is less well definedthan Charlier and colleagues attributeit.1 Unless the word schwannoma waswrongly attributed to a (subcutaneousfrontal) neurofibroma1 (in this re-spect, to support their NF1 diagnosis,the authors cite a study on bonemicro s tructure [and erosion], similarto that encountered in the Cro-Magnon frontal lesion, in NF1 bonedysplasia),2 there is apparently nogood rea s on to force this accuratemicro-CT reconstruction towards asomewhat mixed neurofibromatosisphenotype presenting with N2features, but being labelled as NF1. Amore likely diagnosis, according to theirretrospective micro-CT findings, couldbe that of NF2. An alternative diagnosis(hard to demonstrate) could be thatof mosaic NF2 (or schwannomatosis)based on the presence of a unilateral(right) subcutaneous schwannomaand an ipsilateral enlarged in-ternal auditory meatus. Previousattempts at rediagnosing NF2 (orschwannomatosis) phenotypes on thebasis of clinical and pathological reviewsof old portraits and specimens’ reportshave been made.3 On the basis of theabove considerations, the full facialreconstruction of the Cro-Magnonmale individual1 should not includethe additional smaller facial tumours(ie, the cutaneous neurofibromas),which belong to the NF1 phenotype.Previous CT scan reconstructions haveshown NF1 phenotypes on the basis ofstronger paleoradiological evidence.4Conversely, paleopathological diag-noses of NF1 on the basis of skull orpost-axial skeletal remains have beenattempted in the past,5 generating lesswell defined (weaker) NF1 phenotypesand causing (historical) confusion.We declare no competing interests.*Martino Ruggieri, Andrea D Praticò,Stefano Catanzaro, Stefano Palmucci,Agata Polizzi*******************Unit of Rare Diseases of the Nervous System inChildhood, Department of Clinical and ExperimentalMedicine, Section of Pediatrics and ChildNeuropsychiatry, University of Catania, 95124Catania, Italy (MR, ADP, SC); Radiology I Unit,Department of Medical and Surgical Sciences andAdvanced Technologies, University of Catania,Catania, Italy (SP); and National Centre for RareDiseases, Istituto Superiore di Sanità, Rome, Italy (AP)1 Charlier P, Benmoussa N, Froesch P,Huynh-Charlier I, Balzeau A. Did Cro-Magnon 1have neurofibromatosis type 1? Lancet 2018;391: 1259.。

a r X i v :h e p -p h /9901350v 1 19 J a n 1999On Exotic Solutions of the Atmospheric NeutrinoProblem.Paolo Lipari and Maurizio Lusignoli Dipartimento di Fisica,Universit`a di Roma “la Sapienza”,and I.N.F.N.,Sezione di Roma,P.A.Moro 2,I-00185Roma,Italy Abstract The measurements of the fluxes of atmospheric neutrinos give evidence for the disappearance of muon neutrinos.The determination of the dependence of the disappearance probability on the neutrino energy and trajectory allows in princi-ple to establish unambiguosly the existence of neutrino oscillations.Alternative mechanisms for the disappearance of the neutrinos have been proposed,but do not provide a viable description of the data,if one includes both events where the neu-trinos interact in the detector and ν–induced upward going muons.The proposed mechanisms differ in the energy dependence of the disappearance probability and the upward going muon data that are produced by high energy neutrinos give a crucial constraint.1IntroductionThe measurements of the fluxes of atmospheric neutrinos by the Super–Kamiokande (SK)experiment [1,2,3,4,5]show evidence for the disappearance of muon (anti)–neutrinos.The same indication comes from the older data of the Kamiokande [6]and IMB [7]ex-periments and the recent ones of Soudan–2[8].Also the results recently presented by the MACRO collaboration [9,10]indicate a suppression of the muon (anti)–neutrino flux.The simplest explanation of the data is the existence of νµ↔ντoscillations [1].In the framework of flavor oscillations one should consider the more general case of three flavors[11](with the Chooz experiment [12]giving important contraints to the electron neutrino transitions),and could also envisage more complex scenarios involving sterile states [13].We will not pursue these possibilities here,and we will adopt instead the simplest scenario of two–flavors oscillations as a prototype model that,as we will see,is able to describe successfully the experimental data.We will instead investigate if other forms of ‘new physics’beyond the standard model,different from standard flavor oscillations,can also provide a satisfactory description ofthe existing data.Indeed several other physical mechanisms have been proposed in the literature as viable explanations of the atmospheric neutrino data.In this work we will consider three of these models:neutrino decay[14],flavor changing neutral currents (FCNC)[15,16],and violations of the equivalence principle[17,18]or,equivalently, of Lorentz invariance[19].All these model have the common feature of‘disappearing’muon neutrinos,however the probability depends in different ways on the neutrino energy and path.To discriminate between these models a detailed study of the disappearance probability P and of its functional form is needed.In this work in contrast with previous analyses we will argue that the present data allow to exclude the three‘exotic’models,at least in their simplest form,as explanations of the atmospheric neutrino problem.This is mainly due to the difficulty that these models have tofit at the same time the SK data for leptons generated inside the detector (sub–and multi–GeV)and for up–going muons generated in the rock below it.2DataInfig.1,2and3we show(as data points with statistical error bars)the ratios between the SK data and their Montecarlo predictions calculated in the absence of oscillations or other form of‘new physics’beyond the standard model.Infig.1we show the data for the e–like contained events,infig.2forµ–like events produced in the detector,and infig.3for upward-going muon events,as a function of zenith angle of the detected lepton.In eachfigure we include four lines:the dotted line(a constant of level unity) corresponds to exact agreement between data and no–oscillation Montecarlo,including the absolute normalization.The dot–dashed lines correspond to the assumption that there is no deformation in the shape of the zenith angle distributions,but that one is allowed to change the normalization of each data sample independently.The values obtained are: 1.16for e–like sub-GeV,1.21for e–like multi-GeV,0.72forµ–like sub-GeV,0.74forµ–like multi-GeV,0.56for stopping upward-going muons,and0.92for passing upward-going muons.For two sets of data(sub-GeV and multi-GeVµ–like events)the constant shape fits give very poor descriptions(χ2=26for the sub-GeV and33for the multi-GeV for4 d.o.f).Also the zenith angle shape of the passing upward-going muons is not wellfitted by the no–oscillation Montecarlo(χ2=17for9degrees of freedom).The electron data do not show clear evidence of deformations,although the constant shapefit for the sub-GeV events(χ2=9.7for4d.o.f.)is rather poor.The normalizations of the different data sets are of course strongly correlated,and therefore it is not reasonable to let them vary independently.The other extreme option, that we will adopt in this work for simplicity,is to use one and the same parameter tofix the normalization of the six data samples.The result for constant shapes(i.e.assuming no‘new physics’beyond the standard model)is represented by the dashed lines infig.1, 2and3corresponding to a value0.84and a very poorχ2=280for34d.o.f.).The full lines in thefigures correspond to our bestfit assumingνµ↔ντoscillationswith maximal mixing.We define theχ2as follows:χ2= j N j−αN th j(N SK j,MC/N th j,0)L4Lτνoriginally noted by Wolfenstein[21].There are several theoretical models generically pre-dicting nondiagonal neutrino interactions with matter.In particular such models have been proposed as a possible consequence of R-parity violating interactions in supersym-metric models and suggested as solutions of both the solar[22,15]and atmospheric[15,16] neutrino problems.Let us call Vαβthe effective potential that arises from the forward scat-tering amplitude of a neutrino with a fermion f:να+f→νβ+f.In the standard model√Vµτ=Vτµ=0,and Vµµ=Vττ=2G FǫN f,and different diagonal elements(with Vττ−Vµµ=√sin2 G F2X f√4ǫ2+ǫ′2is proportional to the product of the neutrino energy and pathlength,whereas for the standardflavor oscillations it is the ratio of the same quantities that matters.Equations(2),(3),(5)and(7)are the disappearance probabilities for the four mech-anisms that we will confront with the experimental data.4Flavor OscillationsIt is interesting to discuss how the usualflavor oscillations can successfully reproduce the pattern of suppression measured for the different event samples.The events detected in one particular bin are produced by neutrinos with a predictable distribution of Eνand pathlength L,and therefore of L/Eν,the significant quantity inflavor oscillations.In fig.4,in the top panel we show as a function of L/Eνthe survival probability correspond-ing to maximal mixing and∆m2=3.2×10−3eV2(our bestfit point).Also shown with a dashed line is the survival probability for neutrino decay that we will discuss in the next section.In the second panel we show the L/Eνdistributions of sub–GeVµ–like events in the five zenith angle bins used by the SK collaboration:cosθµ∈[−1,−0.6],[−0.6,−0.2] [−0.2,+0.2],[0.2,0.6]and[0.6,1.0](corresponding to the thick solid,thick dashed,thin dot–dashed,thin dashed and thin solid line).In the third panel we show the corresponding distributions for multi-GeVµ–like events (same coding for the lines).In the fourth panel we show the L/Eνdistributions for upward going muons that stop in the detector in the zenith angle bins:cosθµ∈[−1,−0.8],[−0.8,−0.6][−0.6,−0.4], [−0.4,−0.2]and[−0.2,0.0]with the corresponding lines ordered from right(higher values of L/Eν)to left(lower values of L/Eν).In the last panel we show the same distributions for passing upward going muons in ten zenith angle bins,cosθµ∈[−1,−0.9],...,[−0.1,0.0].Some remarks can be useful for an understanding of the distributions shown infig.4. For the sub-GeV events,one can see that the parent neutrinos have L/Eνspread over a broad range of values.This is due to the poor correlation between the neutrino and muon directions θνµ ≃53◦.For multi-GeV data the distributions are much narrower,reflecting the tighter corre-lation between the neutrino and muon directions, θνµ ≃13◦.Note also that the peaks in the L/Eνdistributions corresponding to sub-GeV and multi-GeV events in the same zenith angle interval are at slightly different points because of the different energy of the parent neutrinos.For up–going stopping muons the width of the distribution is wider than in the multi-GeV case.The correlation between the muon and neutrino directions θνµ ≃10◦is actually better,but the width of the distribution reflects the wider energy range of the neutrinos contributing to this signal.Passing muons are nearly collinear with the parent neutrinos( θνµ ≃2.9◦),but the large energy range of the neutrinos that extend over nearly two decades(Eν≃10–103GeV)results in a wide L/Eνdistribution.All curves in the lower four panels offig.4are normalized to unit area.In order to obtain the suppression due to oscillations in a particular bin,one has to perform the integral:N osc j(sin22θ,∆m2)= dx dN0jup-going muons in a newfit,the bestfit point becomesτν/mν=10000Km/GeV(similar to the previous one),butχ2increases to the much higher value140.5.2Violation of the equivalence principlePerforming afit to the sub-GeV and multi-GeV data of Super Kamiokande with the disappearance probability given by(7)and with maximal mixing(θG=π/4),wefind a minimum in theχ2for a valueδ|φ|=4·10−4Km−1GeV−1(withα=1.10).Theχ2for thisfit is35for18d.o.f.,still a very significant improvement over the standard model case,but not as good as theflavor oscillations result.The survival probability given by our bestfit is shown in the top panel offig.5.The reason of the poorχ2can qualitatively be understood looking atfig.5.Thisfigure is the equivalent offig.4,in the sense that the four lower panels show the distributions in the variable that is relevant in this case,namely L·Eν.The distributions in this variable for the sub–GeV and multi–GeV events have shapes similar to the corresponding ones in L/Eν,because the width of the distributions is mostly determined by the spread in pathlength L.However the average value of the L·Eνof the sub–GeV events is lower than the corresponding one(same zenith angle bin)for multi–GeV events,the opposite of what happens in the L/Eνdistributions,seefig.4.Therefore,parameters describing well multi–GeV events will generally produce too low a suppression for sub–GeV events or viceversa.It can be argued(as the authors of reference[24]do)that taking into account sys-tematic uncertainties the model defined by equation(7)provides a goodfit to the data, however this is not the case if upward–going muons are included in the picture.This should be evident looking at the lower panels infig.5.Upward–going muons are pro-duced by high energy neutrinos and the frequent oscillations do imply a suppression by 50%of passing(and stopping)muons,with no deformation of the zenith angle distribu-tion.This is in disagreement with the corresponding data:in fact,trying tofit all the data together we obtain similar bestfit parameters,δ|φ|=4.5·10−4Km−1GeV−1and α=1.145,but with a very badχ2=142.7for32d.o.f.(the contribution of passing upward–going muon data being∼100).5.3Flavor Changing Neutral CurrentsIn the case of neutrino transitions produced byflavor changing neutral currents,the rˆo le of L/Eνis replaced by X,the column density.This has the fundamental consequence that there is no energy dependence of theflavor conversion.Moreover since air has a density much lower that the Earth’s,the transitions do not develop during the neutrino path in the atmosphere,and therefore down–going neutrinos are unaffected.Note also that there is not a simple relation between the zenith angleθνand the pathlength L because of fluctuations in the neutrino birth position.However,due the air low density,the zenith angleθνdoes define the column density X with a negligible error:the entire down–going hemisphere corresponds to X≃0and to a vanishing transition probability.Performing,as before,afit to the sub-GeV and multi-GeV data of Super Kamiokande with the disappearance probability given by(5)and assuming scattering offdown quarks andǫ′=0(that is maximal mixing),we obtain a bestfit valueǫ=0.4andα=1.08 corresponding to a minimumχ2=38.With increasingǫthe oscillations become more frequent,and essentially all valuesǫ>∼0.4give comparablefits,since for these large values the oscillations can be considered as averaged in the entire up–going hemisphere.The authors of reference[16],exploring the parameter space(ǫ,ǫ′)find two solutions: (a):(0.98,0.02)and(b):(0.08,0.07),that are plotted in the upper panels offig.6.The first solution corresponds to the one that we have found,considering the slow variation ofχ2withǫin the largeǫregion.Theχ2found by the authors of[16]is however better that what wefind,indeed as good as in theflavor oscillation model.We dofind thatfitting the muon data only,without considering the constraint on the normalization coming from the electron data,the FCNC model gives an excellent fit,indeed as good or better than theflavor oscillation model.The reason why,in our fitting procedure,the FCNC model gives not as good afit originates from the fact that the theoretical average value of the suppression for both sub–GeV and multi–GeV muon events for the bestfit parameters is≃0.75,corresponding to no suppression in the down–going hemisphere and∼0.5in the opposite one.The data[2,3]for the double ratio R=(µ/e)Data/(µ/e)MC:R sub=0.61±0.03±0.05,and R multi=0.66±0.06±0.08 indicate a larger average suppression.The allowance of a non perfect correlation between the normalizations of the muons and electron data samples would certainly reduce theχ2 value of ourfit.The inclusion of up–going muons among the data considered,again results in evidence against this model.We recall the fact that the passing muons are essentially collinear with the parent neutrinos and that the experimental zenith angle distribution does not exhibit large sharp features as those predicted for example by solution(b)of[16](see fig.6).Therefore the relative smoothness of the passing muon data allows to exclude a large range of values(ǫ,ǫ′)that correspond to few oscillations in the up–going hemisphere √(that is0.04<∼6Summary and conclusionsThe survival probability P(νµ→νµ)in the case of twoflavorνµ↔ντoscillations has a well defined dependence on the pathlength and energy of the neutrinos.In order to establish unambiguosly the existence of such oscillations it is necessary to study in detail these dependences.In the analysis of the events interacting in the detector,one can study a very wide range of pathlengths(10<∼L<∼104Km)but a much smaller range of neutrino energies close to1GeV(the sub–GeV and multi–GeV samples).Therefore it is not easy to obtain experimental information on the dependence of the survival probability on the neutrino energy.In fact models where the combination L/Eν(flavor oscillations),L·Eν(violations of the equivalence principle)and X≃L(flavor changing neutral currents)is the relevant variable for an oscillating transition probability,have been proposed as viable solutions of these data.Neutrino decay is also dependent on the ratio L/Eν,but with a different functional form.In this study wefind thatflavor oscillations provide a significantly betterfit to the sub–GeV and multi–GeV data samples than the exotic alternatives we have considered, however with a generous allowance for systematic uncertainties the alternative explana-tions can still be considered as viable.Including the upward going muons in thefit the alternative models are essentially ruled out.The upward–going muons are a set ofν–induced events corresponding to much larger Eν:for passing muons the median parent neutrino energy is approximately100GeV,with a significant contribution of neutrinos with energy as large as1TeV,and therefore are in principle a powerful handle to study the energy dependence of the neutrino survival probability.Ifflavor oscillations(where L/Eνis the significant variable)are the cause of the suppression of sub–GeV and multi–GeV muon events,the neutrinos producing passing upward going muons must also oscillate,but with a smaller suppression because of their larger energy;moreover,for the range of∆m2suggested by the lower energy data,one expects a moderate but detectable deformation of the zenith angle distribution.Both effects are detected.In the alternative exotic models we have studied here,high energy events,such as the passing upward–going muons,are suppressed much more(L·Eν)than or as much (X∼L)as the up–going multi–GeV events,in contrast to the experimental evidence.Also in the case of neutrino decay,the upward–going muon data are very poorlyfitted by the model.Of course if neutrino have different masses(and can decay)it is natural to expect oscillations in combination with decay.We have not explored this possibility,but we can conclude that decay cannot be the dominant form of muon neutrino disappearance.Two results of the measurements of upward going–muons are critically important to allow discrimination against exotic models and in favour of usual oscillations:•the stopping/passing(Data/Montecarlo)double ratio for the SK upward–going muons[5]is r=0.56,with a combined statistical and experimental systematic error of0.07.The theoretical uncertainty in the relative normalization of the two sets of data has been estimated as8%in[25];more conservatively the SK collabo-ration[5]has used13%.Quadratically combining the more conservative estimateof the theoretical uncertainty with the experimental errors,the resultingσr is0.1.Therefore the suppression for the high energy passing muons,is weaker than for thelower energy stopping ones at more than four sigma of significance,even allowingfor a rather large uncertainty in the theoretical prediction.This is in contrast with models that predict for the stopping/passing double ratio r a value of unity(flavorchanging neutral currents)or larger(violations of the equivalence principle).•The shape of the through–going upward–going muons zenith angle distribution shows indication of a deformation,although the no–distortion hypothesis(with freenormalization)has a probability close to5%.The deformation if present is a rather smooth one,and the distribution can be used to rule out models(such as FCNC with smallishǫ)that produce deep and marked features in the neutrino distribution (well mapped by the nearly collinear muons).The MACRO collaboration has also obtained results on upward–going muons[9],thatindicate the presence of an angular deformation compatible with the presence offlavor os-cillations(although the oscillationfit even if significantly better that the standard model fit is still rather poor).Preliminary results on events where upward–going muons are produced in(and exit from)the detector,and a second class of events that combines stopping upward–going muons and downward–going muons produced in the detector in-dicate a pattern of suppression that is only compatible with an oscillation probability that decreases with energy[10].Also the Kamiokande collaboration[26]has measured passing upward–going muonswith results in good agreement with Super–Kamiokande,while the Baksan collaboration [27]has obtained results not in good agreement.One should also note that the IMB col-laboration has in the past measured a stopping/passing ratio for upward–going muons in agreement with a no oscillation Montecarlo prediction[28](see[29]for a critical analysis).In conclusion,wefind that the present data on atmospheric neutrinos allow to deter-mine some qualitative features of the functional dependence of the disappearance probabil-ity for muon neutrinos.This probability(smeared by resolution effects)increases with the pathlength L producing the up/down asymmetry that is the strongest evidence for physics beyond the standard model.The difference in suppression between the sub(multi)–GeV muon events and the higher energy through–going muons indicates that the transition probability decreases with energy.These results are in agreement with the predictions ofνµ↔ντoscillations and in contrast with several alternative exotic models.Ifflavor oscillations are indeed the mechanism for the muon neutrinos disappearance,additional data with more statistics and resolution(in L and Eν)should allow to study in more detail the oscillatory structure of the transition probability as a function of the variable L/Eν,unambiguosly determining the physical phenomenon.It is natural to expect that the oscillations involve allflavors and that electron neutrinos participate in the oscillations (with a reduced mixing because of the Chooz limit).The resultingflavor conversions will have a more complex dependence on the neutrino path and energy Eν;the detection of these more subtle effects could become the next challenge for the experimentalists.References[1]Y.Fukuda et al(Super-Kamiokande collaboration),Phys.Rev.Lett.81,1562(1998)(also hep-ex/9807003).[2]Y.Fukuda et al(Super-Kamiokande collaboration),Phys.Lett.B433,9(1998)(also hep-ex/9803006).[3]Y.Fukuda et al(Super-Kamiokande collaboration),Phys.Lett.B43,33(1998)(also hep-ex/9805006).[4]The Super-Kamiokande Collaboration,hep-ex/9812014,submitted to PRL(1998).[5]Takaaki Kajita,for the Super-Kamiokande and Kamiokande collaborations,hep-ex/9810001,to appear in the proceedings of XVIII International Conference on Neutrino Physics and Astrophysics(Neutrino’98),Takayama,Japan,4-9June1998.[6]Kamiokande collaboration,K.S.Hirata et al,Phys.Lett.B205,416(1988),Phys.Lett.B280,146(1992);Kamiokande collaboration,Y.Fukuda et al,Phys.Lett.B335,237(1994).[7]IMB collaboration,D.Casper et 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S.T.Petcov,Phys.Lett.B260,154(1991);E.Roulet,Phys.Rev.D44,935(1991);V.Barger,R.J.N.Phillips and K.Whisnant,Phys.Rev.D44,1629(1991);P.I.Krastev and J.N.Bahcall,hep-ph/9703267(1997).[23]M.Mikheyev and A.Smirnov,Sov.J.Nucl.Phys.42,913(1986).[24]R.Foot,C.N.Leung and O.Yasuda,hep-ph/9809458[25]P.Lipari and M.Lusignoli,Phys.Rev.D57,3842(1998).[26]Kamiokande Collaboration,S.Hatakeyama et al,Phys.Rev.Lett.81,2016(1998).[27]Baksan Collaboration,M.M.Boliev et al,ICRC’95,Rome,Vol1,p.686;ibidem,p.722.[28]IMB collaboration,R.Becker-Szendy et al,Phys.Rev.Lett.69,1010(1992).[29]P.Lipari,M.Lusignoli,and F.Sartogo,Phys.Rev.Lett.74,4384(1995).Figure1:Ratio Data/Montecarlo for the e–like events of Super–Kamiokande.The dot–dashed lines are straight linefits(independent for each panel)to the data points;the dashed lines are the result of fitting all data(included infig.1,2and3)with a common normalization(α=0.84);the solid lines are the result of a calculation withνµ↔ντoscillations with our bestfit parameters for maximal mixing(∆m2=3.2×10−3eV2and a normalizationα=1.15).Figure2:Ratio Data/Montecarlo for theµ–like events of Super–Kamiokande.Seefig.1for a descritionof the lines.Figure3:Ratio Data/Montecarlo for passing and stopping upward–going muons in Super–Kamiokande.Seefig.1for a descrition of the lines.Figure4:Distributions in L/Eνfor the different event classes considered.In the top panel we show the survival probability P(νµ→νµ)for our bestfit withflavor oscillations to all data(solid line)andthe bestfit with neutrino decay to the sub–GeV and multi–GeV data(dashed line).Figure5:Distributions in L·Eνfor the different event classes considered.In the top panel we showthe survival probability P(νµ→νµ)for our bestfit to the sub–GeV and multi–GeV data.Figure6:Distributions in cosθνfor the different event classes considered.In the two top panels weshow the survival probability P(νµ→νµ)of the two bestfit points as calculated in[16].。

计算机专业英语教程（第四版）习题答案计算机专业英语教程(第四版)习题答案计算机专业英语（第四版）课后习题答案Unit 1 [Ex 1] Fb5E2RGbCAP [Ex 2] 1. input, storage, processing, and output 2. power; speed; 1. F 2. T 3. T 4. F 5. T 6. T 7. T 8. T 9. T 10.memoryp1EanqFDPw 3. central processing unit memoryDXDiTa9E3d 5. keyboard; [Ex 3] B. A. central processing unit; 1. F 2. D 2. monitor 3. G 4. C 5. B main memory; 6. A 7. E monitorRTCrpUDGiT 8. H5PCzVD7HxA 4. internal; primary;1. user3. data4. keyboard5. data processingjLBHrnAILg6. information [Ex 4] instructions7. computer8. memory 3. manipulates 4.1. input device2. screen, screen 5. retrievexHAQX74J0X 8. Function6. code7. hard copy[Ex. 5] 新处理器开始IT 技术的新时代New Processors Open New Era of IT Technologies Last week, Intel introduced to the public in Russia and other CIS countries a family of processors Intel Xeon E5-2600. They are more powerful and reliable and, importantly, are very economical in terms of energy consumption. Their1 / 30presence opens a new era in the field of IT technologies and means that the cloud technology is getting closer.LDAYtRyKfEThese processors are primarily designed for servers, data centers (DPC) and supercomputers. The emergence of this class of devices is not accidental. According to the regional director of Intel in Russia and other CIS states Dmitri Konash who spoke at the event, the market of IT-technology is developing so rapidly that, according to forecasts, by 2015 there will be 15 billion devices connected to the Internet, and over 3 billion of active users.Zzz6ZB2Ltk 上周，英特尔公司向俄罗斯和其它独联体国家的公众推出了英特尔Xeon E5-2600 系列处理器，它们更加强大可靠，尤其是在能量消耗方面更加经济实惠。