Measurement of the CP-violating Asymmetries in B0 - KS pi0 and of the Branching Fraction of

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High-statistics measurement of the pion form factor in the rho-meson energy range with the

a rXiv:h ep-e x /6121v329Ja n27High-statistics measurement of the pion form factor in the ρ-meson energy range with the CMD-2detector R.R.Akhmetshin a ,V.M.Aulchenko a,b ,V.Sh.Banzarov a ,L.M.Barkov a,b ,N.S.Bashtovoy a ,A.E.Bondar a,b ,D.V.Bondarev a,b ,A.V.Bragin a ,S.K.Dhawan d ,S.I.Eidelman a,b ,D.A.Epifanov a ,G.V.Fedotovich a,b ,N.I.Gabyshev a ,D.A.Gorbachev a ,A.A.Grebenuk a ,D.N.Grigoriev a,b ,V.W.Hughes d ,F.V.Ignatov a ,S.V.Karpov a ,V.F.Kazanin a,b ,B.I.Khazin a,b ,I.A.Koop a,b ,P.P.Krokovny a,b ,A.S.Kuzmin a,b ,I.B.Logashenko a,c ,P.A.Lukin a,b ,A.P.Lysenko a ,K.Yu.Mikhailov a ,ler c ,shtein a,b ,I.N.Nesterenko a,b ,M.A.Nikulin a ,V.S.Okhapkin a ,A.V.Otboev a ,E.A.Perevedentsev a,b ,A.S.Popov a ,S.I.Redin a ,B.L.Roberts c ,N.I.Root a ,A.A.Ruban a ,N.M.Ryskulov a ,A.G.Shamov a ,Yu.M.Shatunov a ,B.A.Shwartz a,b ,A.L.Sibidanov a ,V.A.Sidorov a ,A.N.Skrinsky a ,V.P.Smakhtin f ,I.G.Snopkov a ,E.P.Solodov a,b ,J.A.Thompson e ,Yu.V.Yudin a ,A.S.Zaitsev a,b ,S.G.Zverev aa Budker Institute of Nuclear Physics,630090,Novosibirsk,Russiab Novosibirsk State University,630090,Novosibirsk,Russiac Boston University,Boston,MA 02215,USAd Yale University,New Haven,CT 06511,USAe University of Pittsburgh,Pittsburgh,PA 15260,USAf Weizmann Institute of Science,76100,Rehovot,IsraelAbstractWe present a measurement of the pion form factor based on e +e −annihilation data from the CMD-2detector in the energy range 0.6<√1IntroductionMeasurement of the pion form factor|F(q2)|,or the cross section e+e−→π+π−,√in the center-of-mass(c.m.)energy rangeσ(e+e−→µ+µ−),(1) and has been an important topic in high energy physics since the quark model was established.Recent interest to the measurement of R(s)was stimulated by the measurement of the anomalous magnetic moment of the muon aµat BNL [1]with the unprecedented precision of0.54ppm.The measured value of aµis about2to3standard deviations above the Standard Model expectation,which could indicate the long-sought existence of New Physics.When integrated with—the leading order the proper kernel function,R(s)gives a value of a(had,LO)µhadronic contribution to aµ.The accuracy of the SM prediction,currently ≈0.55ppm[2],is dominated by the knowledge of R(s)at√s<1.4GeV has been studied at the electron-positron collider VEPP-2M[3](Novosibirsk,Russia).Two experiments,CMD-2 [4,5]and SND[6],started in1992and1995,respectively,and continued up to 2000,when the collider was shut down.The CMD-2detector consists of the drift chamber,the proportional Z-chamber,the barrel CsI calorimeter,the endcap BGO calorimeter and the muon range system.The drift chamber,Z-chamber and the endcap calorimeters are placed inside a thin superconducting solenoid with aﬁeld of1T.CMD-2collected e+e−→π+π−data atﬁve separate energy scans,starting from1994.Approximately106e+e−→π+π−events were selected for analysis.From analysis perspectives,the VEPP-2M energy range is naturally subdivided√into three intervals.In the energy range0.36<s<1.4GeV,covered in the1997run[8],is distinguished by therelatively small value of the e+e−→π+π−cross section.The bulk of the data√were collected in the energy range0.6<2Data Analysis2.1OverviewThe data were collected at29energy points covering the c.m.energy range √0.6<where a is theﬁnal state(a=ee,µµ,ππ,cosmic),N a is the number of events of the type a and f a(E+,E−)is the probability density function(p.d.f.)for an event of type a to have the energy depositions E+and E−.It is assumed that E+and E−are independent for events of the same type, therefore the p.d.f.can be factorized asf a(E+,E−)=f+a(E+)·f−a(E−),where f±a(E)are the energy deposition p.d.f.s for individual e±,µ±,π±and cosmic muons.This assumption is not entirely correct.The energy deposition depends on the calorimeter thickness seen by particle(≈8X0at900).Since the incident angles at which the two particles in theﬁnal state hit the calorimeter are nearly the same,that leads to a correlation between E+and E−.This eﬀect is corrected for by the recalibration of the energy deposition.The second source of the correlation is introduced by initial state radiation.This eﬀect will be discussed in more detail in section2.4.The overlap between the energy deposition of electrons and pions is rather small,which makes the described procedure very robust.However,the energy deposition of muons and pions is not that diﬀerent,therefore the small errors in the p.d.f.for these particles lead to a large correlated error for Nππand Nµµ. To avoid this problem,the ratio of the number ofµ+µ−pairs to the number of e+e−pairs isﬁxed during the minimization at the value calculated according to QED with radiative corrections and detection eﬃciencies taken into account:Nµµσee·(1+δee)εee,whereσare the Born cross-sections,δare the radiative corrections andεare the eﬃciencies.The speciﬁc form of the energy deposition functions(p.d.f.s)was evaluated in the variety of studies.P.d.f.s for electrons(positrons)and background muons were obtained with the specially selected subsets of data.P.d.f.s for minimum ionizing particles(muons and pions without nuclear interactions)were extracted from the simulation.The complete p.d.f.for pions with nuclear interactions taken into account was obtained from the analysis of the energy deposition of tagged pions coming from theφ(1020)→π+π−π0decay,a high-statistics mea-surement of which was performed at CMD-2in separate data taking runs[11]. In all cases,only the functional form of p.d.f.s wasﬁxed.The particular values of the function parameters were determined by the minimization procedure.To simplify theﬁnal error calculation,the likelihood function(2)is rewritten to have the following globalﬁt parameters:(N ee+Nµµ)and Nππ/(N ee+Nµµ) instead of N ee and Nππ(with Nµµ/N ee and N cosmicﬁxed).The pion form factor is calculated as:|Fπ|2=Nππσππ·(1+δππ)(1+∆N)(1+∆D)εππ·(1+∆sep)−∆3π,(3)4where the ratio Nππ/(N ee+Nµµ)is determined in the minimization of(2),σare the corresponding Born cross sections,integrated over theﬁducial volume,δare the radiative corrections,ǫare the detection eﬃciencies,∆D and∆N are the corrections for the pion losses caused by decays inﬂight and nuclear interactions,respectively,∆3πis the correction forω→π+π−π0background and∆sep is the correction for the systematic shift,introduced by the separation procedure.In the case of e+e−→π+π−,σππcorresponds to point-like pions.2.2EﬃciencyThe most signiﬁcant diﬀerence between1994-95and1998data analyses lies in the measurement of the detection eﬃciencyε.The eﬃciencyεis the product of the reconstruction eﬃciency and the trigger eﬃciency.For the1994-95data the reconstruction eﬃciency is high(≈97%–99%)and the same for all threeﬁnal states—studies showed that the diﬀerence does not exceed0.2%.Therefore,the eﬃciencies cancel in(3).In the run of1998the CMD-2drift chamber showed signs of aging.That led to a lower reconstruction eﬃciency and,more important,to diﬀerent values of the eﬃciency for the threeﬁnal states.This diﬀerence,if unaccounted for, would lead to a signiﬁcant systematic error on the form factor.Therefore,a direct measurement of the reconstruction eﬃciency for all types of collinear events was necessary.This measurement is based on a well-known technique.A test sample of collinear events is selected using criteria based on the calorimeter data,which are uncorrelated with the standard selection criteria based on the information from the tracking system.The eﬃciency is calculated as a fraction of test events, which passed the standard selection criteria for collinear events.The selection criteria for the test sample are the following:1.The event was triggered by the trackﬁnder.2.There are exactly two clusters in the calorimeter.3.There is a hit in the Z-chamber near each cluster.This requirement selectsthe clusters produced by a charged particle.4.The clusters are collinear if one takes into account the particle deﬂectionin the detector magneticﬁeld:|π−(Θ1+Θ2)|<0.1,||π−|ϕ1−ϕ2||−ϕ0|<0.1,whereΘandϕare the polar and azimuthal angles of the cluster and ϕ0is the expected azimuthal deﬂection angle of particles in the CMD-2 magneticﬁeld of1T.The test event sample is subdivided into three classes:5E 1, MeVE2,Me VFigure 1:Deﬁnition of three classes of test events1.For the e +e −→e +e −subset,the energy deposition of each cluster isbetween E min =(0.82·E B −40)and E max =(0.82·E B +50)MeV.2.For the e +e −→π+π−subset,the energy deposition of one cluster isbetween 70and 120MeV and the energy deposition of another cluster is between 120MeV and E min =(0.82·E B −40)MeV.3.For the e +e −→µ+µ−subset,the energy deposition of each cluster isbetween 70and 120MeV.The deﬁnitions of the three classes of test events are demonstrated in Fig.1.The e +e −→e +e −events have a unique signature of two high-energy clusters in the calorimeter,therefore this subset contains virtually no background.On the contrary,the e +e −→π+π−and e +e −→µ+µ−test samples contain a sig-niﬁcant contribution of cosmic muon background.To subtract the background,the additional requirement to have at least one reconstructed track was added to the selection criteria for test events.This cut rejects only ≈0.1%of events,and therefore does not introduce a signiﬁcant contribution to the systematic error of the eﬃciency measurement.For each class of the test events,the distributions of the z-coordinate of the track origin were collected for events which pass the standard selection criteria and for events which failed them.The distributions,shown in Fig.2,were ﬁtted with the combination of a Gaussian-like distribu-tion,which represents the beam-originating events,and a uniform distribution,which represents the background events.The eﬃciency for a particular class of test events is calculated asε=N passZ, cm 02000400060008000(a)Test “µµ”events which passed standardselection criteria Z, cm0200400600(b)Test “µµ”events which failed standard se-lection criteriaFigure 2:Position of the track origin along the beam axis.The distributions are the sum of the gaussian-like signal and the ﬂat background.where N pass and N fail ,obtained from the ﬁt,are the integrals of the Gaussian-like distributions for the cases,when test event pass and fail the standard selection criteria.The results of the eﬃciency measurement,εee and εππ,µµ/εee ,are shown in Fig.3.The wave-like structure of the eﬃciency as a function of energy is explained by varying conditions of data taking.The drift chamber performance was changing during the run,generally degrading with time as we scanned from higher to lower energies.Additional problems occurred during a long period when data were taken around the ωmeson mass.The e +e −→µ+µ−test sample in addition to e +e −→µ+µ−contains those e +e −→π+π−events,where both pions in the ﬁnal state interact as the minimum-ionizing particles (MIP).While it is possible to extract separate ef-ﬁciencies for e +e −→µ+µ−and e +e −→π+π−events,the results have poor statistical precision.Therefore,a diﬀerent approach was used.Since the dif-ference between µ-and π-signals in the drift chamber is much smaller than the diﬀerence between µ-and e -signals,the diﬀerence (εµµ−εππ)is much smaller than (εee −εππ).That allows us to measure the combined eﬃciency εMIP using the combined e +e −→µ+µ−and e +e −→π+π−test event samples,and then to extract the individual eﬃciencies εµµand εππ,applying a small correction estimated with the help of the GEANT simulation (Fig.4(a))to εMIP .The procedure described does not account for Bhabha events where the electron or positron in the ﬁnal state radiates a high-energy photon while passing the wall of the beam pipe or the inner part of the drift chamber.Such events mostly (>90%)disappear from the test sample,as they typically have more than two clusters in the calorimeter.This contribution to the Bhabha reconstruction ineﬃciency was evaluated in the separate simulation.It changes slowly from0.3%at√s =1000MeV (Fig.4(b)).The eﬃciency measurement was tested with the full GEANT simulation,where the e +e −→e +e −(γ),µ+µ−(γ),π+π−(γ)events were generated and7Beam Energy, MeV E f f i c i e n c y(a)Reconstruction eﬃciency for e +e −→e +e −events Beam Energy, MeVR a t i o ε(m i p )/ε(e e )(b)Ratio of combined reconstruction eﬃ-ciency of e +e −→µ+µ−and e +e −→π+π−events and eﬃciency of e +e −→e +e −eventsFigure 3:Measurement of the reconstruction eﬃciency for all types of collinear eventse +e −→π+π−and µ+µ−events separatelyand the combined eﬃciency e +e −events from the bremsstrahlung in the beam pipe materialFigure 4:Reconstruction eﬃciency measurement for the simulated data set8Beam Energy, MeV T r ig g e rE f f i ci e n cy,B ha b h a(a)Trigger eﬃciency for e +e −→e +e −events Beam Energy, MeVTrigge rEfficie ncyRatio ,Bhabha /(µµ,ππ)(b)Ratio of the trigger eﬃciency for e +e −→µ+µ−and e +e −→π+π−eventsand for e +e −→e +e −eventsFigure 5:Measurement of the trigger eﬃciencymixed together.The drift chamber performance in the simulation was tuned to represent adequately the performance seen with the data.The complete procedure described above was applied to the simulated data.It was found that the diﬀerence between the measured and the true eﬃciencies does not exceed 0.2%.The events used in the form factor analysis were triggered by the trackﬁnder —the dedicated track processor.The trackﬁnder generated positive decision when at least one track candidate was identiﬁed in the rmation about all identiﬁed candidates is saved in the raw data stream.The trigger eﬃciency measurement is based on the fact that there are two well-separated tracks in the ﬁnal ing one track to ensure the trigger,the eﬃciency for a single track was calculated as the probability for the trackﬁnder to identify a track candidate in the vicinity of the second track.The trigger eﬃciency εt was calculated from the single track eﬃciency ε1as εt =2ε1−ε21.The same three samples of testevents as for the reconstruction eﬃciency were used to measure the trigger eﬃciency.The contribution of the cosmic back-ground was subtracted using the Z -distribution of the track origin.The results of the measurement are shown in Fig.5.The trigger eﬃciency for e +e −→µ+µ−and e +e −→π+π−was found to be the same within 0.2%.The diﬀerence be-tween eﬃciencies for e +e −→e +e −and e +e −→π+π−events,important for theform factor analysis,is negligible for energies √Figure6:Radiative corrections forΘmin=1.1,|∆Θ|<0.25,|∆ϕ|<0.15. Solid points and line represent the results of the calculations with the detector resolution taken into account.Circles represent the results of the calculations with the“ideal”detector.2.3Radiative correctionsThe radiative correctionsδin(3)were calculated according to[12].The radia-tive corrections for e+e−→e+e−and e+e−→µ+µ−account for the radiation by the initial andﬁnal particles and for the eﬀects of the vacuum polarisation. The radiative corrections for e+e−→π+π−account for only the radiation by the initial andﬁnal particles.The calculation was performed using the fast Monte Carlo technique.The events have beenﬁrst generated with the weak cuts in the wide solid angle, then the angles of the particles were smeared with the detector resolution and,ﬁnally,the selection cuts were applied.The detector resolution was obtained from theﬁt of the experimental∆ϕand∆Θdistributions with the convolution of the ideal∆ϕand∆Θdistributions,obtained from the primary generator, and the detector response function.The results of the calculation are shown in Fig.6.It is clear that the contri-bution from the detector resolution is negligible for the standard data selection. It becomes much more important if stricter cuts are applied.As an indirect test of calculations,the whole data analysis procedure was repeated for diﬀerent cuts on∆Θ,∆ϕandΘmin.This test probes all pieces of the data analysis procedure.But since these cuts aﬀect the radiation corrections much stronger than any other contribution,such as the eﬃciency,the procedure mainly tests the radiative corrections.The results are shown in Fig.7.No changes outside the allowed limits were observed.10(ﬁducial volume)Figure7:Diﬀerence between the results of the form factor measurements per-formed with diﬀerent selection cuts.2.4Other correctionsThe corrections for the pion decay inﬂight∆D,for the nuclear interactions ofpions with the material of the beam pipe and the drift chamber∆N and for the e+e−→3πbackground∆3πwere calculated with the help of simulation.The values of the corrections are the same as those used for the94-95data analysis[9].One new correction,denoted as∆sep in(3),was applied to the98data set. An event where one of the original particles emits a hard photon is usually rejected because theﬁnal particles are not back-to-back.But if both initial particles radiate a hard photon,theﬁnal particles could stay back-to-back and therefore be accepted for the analysis.The eﬀect of this double bremsstrahlung on the selection eﬃciency was taken into account in the radiative correction calculation.But this eﬀect also introduces a correlation between the energy de-positions of twoﬁnal particles in the calorimeter,which introduces a systematic shift of the likelihoodﬁt results.Two approaches were used to take this eﬀect into account.Theﬁrst one,ap-plied in the analysis of the data above theϕ-meson,is based on the minimization of the modiﬁed likelihood function,where the correlation term is introduced[8]. The diﬀerent approach was used here.The correction to the results of the event separation was evaluated using the Monte Carlo simulation and applied to the ﬁnal result.The size of the correction is small(≈0.3%),so this simple approach does not introduce any sizable systematic uncertainty.The correction is shown in Fig.8.The same correction was evaluated when the double bremsstrahlung was switched oﬀin the Monte Carlo simulation.A signiﬁcantly smaller eﬀect was observed,which proves that the double bremsstrahlung is the main source of the shift.11Figure8:Correction∆sep for the correlation of the energy depositions of two particles due to the initial state radiationSource Contribution,%Total0.8Table1:Main sources of the systematic errors122.5Systematic errorsThe main sources of the systematic error are summarized in Table1.Some con-tributions have not changed since the94-95data analysis and are not discussed here,namely theﬁducial volume and the corrections for the pion losses.The event separation was tested with the help of simulation.In these studies the double bremsstrahlung was switched oﬀin the primary generator,as wasdiscussed in section2.4.We studied how the following contributions aﬀect the results:the calorimeter calibration,the initial andﬁnal state radiation,“dead”crystals in the calorimeter.The largest observed shift was about0.2%,whichwas taken as a systematic error estimate.The additional double bremsstrahlung correction is small,so it was assumed that it gives no contribution to the sys-tematic error.The systematic error of the eﬃciency measurement was discussed in detail in section2.2.We estimate this contribution to the systematic error to be lessthan0.5%.It should be noted that the diﬀerence between the reconstruction eﬃciencies for e+e−→e+e−and e+e−→π+π−events on average is≈2%and never exceeds5%.Therefore,the estimated0.5%suggests that this diﬀerenceis known to about25%.The absolute beam energy was determined from the value of the collider magneticﬁeld,which provided an accuracy better than∆E/E<10−3.The energy uncertainty leads to a0.3%systematic error of the contribution to thea(had,LO)µ,which we include in the total systematic error in Table1.The absoluteenergy scale can be calibrated with the measurement of the mass ofω-meson,theonly narrow resonance in the energy range under analysis.To do the calibration we performed aﬁt of the measured form factor in which theωmass was a freeﬁt parameter,and obtained Mω(these data)−Mω(PDG2006)=(0.4±0.3) MeV,or∆E/E≈(5±4)·10−4.An independent determination of theωmass with the same data set was performed in e+e−→π0γchannel[13].The result Mω(π0γ)−Mω(PDG2006)=(0.55±0.24)MeV,is consistent with our measurement.The contribution of the radiative corrections to the systematic error is deter-mined by the precision of the ratio(1+δππ)/(1+δee).The radiative correction to eachﬁnal state is known to0.2%or better.We’ve added the contributions from twoﬁnal states linearly to obtain0.4%as the total contribution.Taking the detector resolution into account does not change the results signiﬁcantly, therefore no additional contribution to the systematic error was added.3ResultsThe measured values of the pion form factor are shown in Table2.Only the statistical errors are shown.Also presented are the values of the bare e+e−→π+π−(γ)cross-section deﬁned asσ0ππ(γ)=πα2πΛ(s) ,13√600330.1±13.7630415.6±11.5660529.1±12.7690746.4±14.77201053.6±13.57501296.6±19.07601311.4±25.07641325.8±21.77701302.0±21.77741332.2±15.47781296.0±12.27801237.5±16.07811178.3±15.27821111.7±5.67831007.0±11.7784922.4±10.1786844.1±10.2790836.6±16.4794822.5±12.8800794.8±10.4810701.6±9.9820602.9±6.6840443.3±5.1880239.0±3.4920145.4±2.0940108.0±2.595097.2±2.195886.0±1.897078.0±1.8Table2:Results of the pion form factor measurement based on the CMD-21998 data.Only statistical errors are shown.14E C.M., MeV|F π|21020304050600700800900Figure 9:Fit of the pion form factor measured in this work15sured in this work with the previous measure-ments by CMD-2and SND.The values are shown relative to theﬁt of the CMD-21998 data.sured in this work with the KLOE measure-ment.Theﬁlled area shows the statistical er-ror and the lines show the systematic error of the KLOE data.Figure10:Comparison of the pion formfactor measured in this work with other measurementswhere the factor|1−Π(s)|2excludes the eﬀect of leptonic and hadronic vac-uum polarization and the factorΛ(s)provides a correction for theﬁnal state radiation.To obtain the parameters of theρ(770)meson,the measured form factor was ﬁtted with the same model,as was used in our previous measurement,which includes the contributions of theρ(770),ω(782)andρ(1450)and is based on the Gounaris-Sakurai parameterization of theρmeson:Fπ(s)=GSρ(770)(s)· 1+δe−iΦρωs1+β.It is assumed thatωdecays to2πthroughρ−ωmixing only.More details on this model and the values of allﬁxed parameters can be found in[9].The16ExperimentCMD-2,1994-1995dataCMD-2,1998data(this work)SNDKLOEs<958MeV.Theﬁrst error is statistical and the second is systematic.following parameters of theρ(770)andω(782)were obtained:Mρ=(775.97±0.46±0.70)MeV,Γρ=(145.98±0.75±0.50)MeV,Γ(ρ→e+e−)=(7.048±0.057±0.050)keV,B(ω→π+π−)=(1.46±0.12±0.02)%,Φρω=10.4◦±1.6◦±3.5◦,β=−0.0859±0.0030±0.0027.Theﬁrst error is statistical and the second is systematic taking into account thesystematic uncertainties of the data and the beam energy.These results are in good agreement with our previous measurement[9,10].It should be noted that in our parameterizationβrepresents the combined eﬀect of theρ(1450)and ρ(1700)and therefore cannot be used to obtain theρ(1450)→2πbranching ratio.The value of B(ω→π+π−)is calculated fromδassuming VDM relations andΓωee=(0.595±0.017)keV,as described in[9].Comparison between the results of this,our previous and the recently pub-lished SND measurement[14,15]is shown in Fig.10(a).The average diﬀerence between the two CMD-2results is(0.4%±0.6%±0.8%),while between the SND and this measurement it is(−1.2%±0.4%±1.5%),where theﬁrst error is statistical and the second is the uncorrelated systematic one.Recently the KLOE collaboration published theﬁrst measurement of the e+e−→π+π−cross-section[16]based on the analysis of the distribution of the invariant mass of two pions in the e+e−→π+π−+γISRﬁnal state(the initial state radiation or ISR approach).Comparison between the results of KLOE and our measurements is shown in Fig.10(b).Only the statistical errors areshown.There is some systematic diﬀerence between the results,particularly in √the energy rangeintegration of the experimental points using a trapezoidal method.All four mea-surements give consistent values of aππ,LO.In accordance with the discussion above,the CMD-2result based on this measurement(1998data)has better statistical error than the result based on our previous study.The combined uncertainty of the new measurement is about the same as before.This work is partially supported by the Russian Foundation for Basic Re-search,grants03-02-16477,03-02-16280,04-02-16217,04-02-16223,04-02-16434, 05-02-17169,06-02-16156,06-02-16445,06-02-26859and the U.S.National Sci-ence Foundation.References[1]G.W.Bennett et al.,Phys.Rev.D73(2006)072003.[2]M.Davier and W.J.Marciano,Annu.Rev.Nucl.Part.Sci.54(2004)115.[3]V.V.Anashin et al.,Preprint Budker INP84-114,Novosibirsk,1984.[4]E.V.Anashkin et al.,ICFA Instrumentation Bulletin5,18(1988).[5]E.V.Anashkin et al.,Instrum.Exp.Tech.49(2006)798(translated fromPrib.Tekh.Eksp.49(2006)63).[6]M.N.Achasov et al.,Nucl.Instrum.Meth.A449(2000)125.[7]V.M.Aulchenko et al.,JETP Lett.84(2006)413(translated from PismaZh.Eksp.Teor.Fiz.84(2006)491).[8]V.M.Aulchenko et al.,JETP Lett.82(2005)743(translated from PismaZh.Eksp.Teor.Fiz.82(2005)841).[9]R.R.Akhmetshin et al.,Phys.Lett.B527(2002)161.[10]R.R.Akhmetshin et al.,Phys.Lett.B578(2004)285.[11]R.R.Akhmetshin et al.,Phys.Lett.B642(2006)203.[12]A.B.Arbuzov et al.,Eur.Phys.J.C46(2006)689.[13]R.R.Akhmetshin et al.,Phys.Lett.B605(2005)26.[14]M.N.Achasov et al.,JETP101(2005)1053(translated from Zh.Eksp.Teor.Fiz.128(2005)1201).[15]M.N.Achasov et al.,JETP103(2006)380(translated from Zh.Eksp.Teor.Fiz.130(2006)437).[16]A.Aloisio et al.,Phys.Lett.B606(2005)12.18。

Diffusion on a solid surface Anomalous is normal

a r X i v :c o n d -m a t /0310589v 1 [c o n d -m a t .s t a t -m e c h ] 24 O c t 2003Diﬀusion on a solid surface:Anomalous is normalJ.M.Sancho 1,casta 2,K.Lindenberg 3,I.M.Sokolov 4and A.H.Romero 5(1)Departament d’Estructura i Constituents de la Mat`e ria,Facultat de F´ısica,Universitat de Barcelona,Diagonal 647,E-08028Barcelona,Spain (2)Departament de F´ısica Aplicada,Universitat Polit`e cnica de Catalunya Avinguda Dr.Mara˜n on 44,E-08028Barcelona,Spain.(3)Department of Chemistry and Biochemistry 0340,and Institute for Nonlinear Science,University of California,San Diego,La Jolla,California A.(4)Institut f¨u r Physik,Humboldt Universitæt zu Berlin,Newtonstr.15,12489Berlin,Germany.(5)Advanced Materials Department,IPICyT,Camino a la presa San Jos´e 2055,CP 78216,San Luis Potos´ı,SLP,M´e xico.(Dated:February 2,2008)We present a numerical study of classical particles diﬀusing on a solid surface.The particles’motion is modeled by an underdamped Langevin equation with ordinary thermal noise.The particle-surface interaction is described by a periodic or a random two dimensional potential.The model leads to a rich variety of diﬀerent transport regimes,some of which correspond to anomalous diﬀusion such as has recently been observed in experiments and Monte Carlo simulations.We show that this anomalous behavior is controlled by the friction coeﬃcient,and stress that it emerges naturally in a system described by ordinary canonical Maxwell-Boltzmann statistics.PACS:05.40-a,68.43.Jk,68.35.FxDiﬀusion of atoms,molecules,and clusters on solid surfaces occurs in a number of modern technologies in-volving self-assembled molecular ﬁlm growth,catalysis,and surface-bound nanostructures [1].The study of the motion of small and large organic molecules [2,3],and of adsorbed metal clusters composed of tens and even hundreds of atoms [4,5],has led to the unexpected ob-servation that,as with single atoms [6],long jumps may play a dominant role in these motions.Theoretical,numerical,and phenomenological discus-sions of surface diﬀusion have led to the clear understand-ing that jumps beyond nearest neighbors are ubiquitous in some parameter regimes [7].However,these studies focus on the fact that the motion is necessarily diﬀusive (which is the case at very long time scales).The possi-bility that jumps can be so long as to lead to superdiﬀu-sive motion over appreciable intermediate time scales is recognized as an interesting problem,but one in which L´e vy walks or ﬂights [8]are invoked as a model input.AlthoughL´e vy-walk-like behavior is clearly observed in Hamiltonian systems [9,10]and in microcanonical sim-ulations [10,11],it is generally believed that such a ﬁne signature of chaos is fully smeared away by thermal ﬂuc-tuations.In the present work we show that L´e vy-like statistics appear quite naturally over long time scales within the usual Langevin framework for underdamped motion in a periodic or a random potential.While a detailed analysis of surface diﬀusion requires extensive calculations (e.g.,ab initio ,or molecular dy-namics),even the most powerful currently available com-puters can not carry such calculations to anywhere near experimentally relevant time scales [12].Moreover,cur-rent experimental probes of the topography of surfaces,scanning tunneling microscopy and atomic force mi-croscopy,are usually carried out at relatively high tem-peratures,which leads to additional diﬃculties for ﬁrst-principles calculations.Therefore,simpler approaches are essential and valuable [7].We consider a generic model of classical particles mov-ing in a two-dimensional potential,under the action of thermal ﬂuctuations and dissipation,the important con-trol parameter being the friction coeﬃcient.In spite of the simplicity of the model,we ﬁnd that it is able to reproduce the entire range of experimentally and compu-tationally observed phenomena,from superdiﬀusion all the way to subdiﬀusion.The equation of motion of a particle of mass m on the surface ism ¨x=−∇V (x /λ)−µ˙x +ξ(t )(1)where λis the characteristic length scale of the poten-tial.The parameter µis the coeﬃcient of friction,andthe ξi (t )are mutually uncorrelated white noises that obey the ﬂuctuation-dissipation relation ξi (t )ξj (t ′) =2µk B T δij δ(t −t ′).We ﬁrst consider the nonseparable pe-riodic potentialV (x,y )=V 0cos πx λ cos πx λ,(2)where V 0is the barrier height at the saddle points.Equation (1)can be rewritten in scaled dimensionless variables,r x =x/λ,r y =y/λ,and s =mV 0.(3)We study four properties of the motion of the particle:the mean square displacement,the dependence of the diﬀusion coeﬃcient on friction,the probability density function of displacements,and the velocity power spec-trum.Normal diﬀusive behavior is characterized by a lin-ear time dependence of the mean square displacement,2−2020406080100−20020406080100−20−1010203040−40−30−20−1001020FIG.1:Left:A trajectory for γ=1over t =20,000time units.Right:A trajectory for γ=0.04over t =15,000time units.The period of the potential is λ=4.Note the diﬀerent scales in the two panels.r 2(s ) ∼s .Non-diﬀusive behavior shows a diﬀerent time dependence, r 2(s ) ∼s α,with α>1(<1)for superdiﬀusive (subdiﬀusive)motion.In Fig.1we show typical trajectories obtained for two friction coeﬃcients upon numerical simulation of the equations of motion with T =0.2(we use this value throughout).One (left panel)is for a large friction coeﬃcient,and the particle follows typical diﬀusive motion characterized by short steps of length ∼λand frequent changes in direction.The other (right panel)corresponds to a small friction coeﬃcient and clearly shows the preponderance of long (≫λ)tracks along cartesian coordinates.The evolution of r 2 averaged over 1000particles is shown in Fig.2for several friction coeﬃcients.For very long times the motion is diﬀusive,as expected,but for small γand at intermediate times there is clear superdif-fusive ballistic (α=2)behavior over several decades in time.This is reﬂective of the long straight stretches seen in the low-γtrajectory in Fig.1.We stress that this behavior has emerged naturally and has not required ex-plicit insertion of any but ordinary thermal ﬂuctuations in the model.Eventhough the motion of the particle may include long superdiﬀusive stretches,at long times the motion is necessarily diﬀusive.The dependence of the diﬀusion coeﬃcient on the friction for small and for large γcan be obtained analytically using the approximate relation D ≈ l 2 /2τ,where l 2 is the mean square size of a jump out of one well and into another,and τ−1is the mean jump rate (related to the familiar “mean escape rate”).In the overdamped regime,jumps typically occur from one well to a neighboring well,so l 2 ≈1.Familiar Kramers formulas can be used to obtain the mean escape rate [13],with the resultD ∼1γ22e −1γe −14γe −1long time asymptotic dynamics.The interesting inter-mediate dynamics in the low friction regime that gives rise to long stretches of ballistic motion is reﬂected in the probability distribution function(pdf)of particle dis-placements r.This pdf is shown in Fig.3forγ=0.0004 and tree diﬀerent time intervalsτs.For comparison,we also show a typical pdf for high damping(γ=1)at the intermediate time interval.In the high-γcurve the high-est maximum corresponds to no jumps(by far the most likely event at short times).The next is associated with jumps to a nearest neighbor well,and so on.In con-trast,the low-γcurves show a very diﬀerent behavior, with features strongly resembling those of a L´e vy-walk model[9,15]:a peak at small displacements,a power-law intermediate regime,and a side hump at high displace-ments.Each of these is a distinct signature of L´e vy-walk-like dynamics,but one must be cautious in the detailed interpretation of these components.The persistent small displacement peak is associated with long trapping peri-ods during which a particle does not move at all because its energy is not suﬃcient to overcome the barrier.The high displacement peak,which moves outward with ve-locity of order unity,is associated with ballistic motion of those particles that acquire enough energy to move (and lose it very slowly).Genuine L´e vy-walk dynamics also exhibit a low displacement peak and a superdiﬀu-sive peak separated by a power law behavior,but there are some important diﬀerences.First,our distribution reﬂects ballistic transport in the intermediate regime(in the language of Ref.[15],ballistic transport occurs when 0<α<1in the L´e vy model),whereas the regime where the L´e vy model shows the features we have described is associated with sub-ballistic(but still superdiﬀusive)be-havior(again,in the language of Ref.[15],the behavior when1<α<2).Second,the slope in our power law regime(approximately0.7)is not related to the expo-nentαin the mean square displacement as it is for the L´e vy walk(where the slope is4−α).Third,our side hump is strongly broadened whereas the side hump in the L´e vy-walk model is associated with motion at a single constant velocity.In our case the velocity varies accord-ing to the equilibrium Maxwell-Boltzmann distribution. Nevertheless,the qualitative features of our distribution track those of the L´e vy walk.Note that the existence of the pronounced side hump reﬂects the fact that the particles performing long steps(“ﬂights”)are those with a velocity in the tail of the Maxwellian distribution. Long ballistic excursions imply velocity correlations over considerable time intervals.The velocity power spectrum S(ω)= v(ω)v(−ω) for diﬀerent values ofγ√is shown in Fig.4.The pronounced peak atω0=πs10−410−310−210−110101<r 2>/4sFIG.6: r 2 /4s for a particle in the random potential for γ=0.0004(solid),0.008(dotted),0.04(dashed)and 0.8(dot-dashed).The straight-line segment has unit slope as a guide to the eye.Inset:Exponents αversus friction coeﬃcient γ.overdamped case [19],further theoretical and numerical support are needed to assess whether superdiﬀusion is the asymptotic behavior in the underdamped case.We summarize our ﬁndings.We have explored the be-havior of a particle in a two-dimensional potential de-scribed by ordinary Langevin dynamics under conditions of thermal equilibrium.In a periodic potential,in the underdamped regime,the motion of the particle includesa ballistic range that can extend over many decades of time.The pdf of the particle’s displacements under these conditions shows a structure strongly resembling one for L´e vy walks.This may explain a number of observations involving superdiﬀusive motion of organic molecules [3]and atomic clusters [5]on surfaces without the need to invoke extraordinary ﬂuctuations beyond the usual ther-mal description.The long-time behavior is diﬀusive in all cases,and we have been able to predict theoretically the dependence of the diﬀusion coeﬃcient on friction over essentially the entire range of values of the friction pa-rameter with no adjustable parameters .The situation in a random potential is even more complex,and exhibits a wide range of subdiﬀusive to superdiﬀusive regimes.Fur-ther analysis of the random potential case,and a more extensive presentation of the periodic problem,will be detailed elsewhere [20].This work was supported by the MCyT (Spain)under project BFM2003-07850,by the Engineering Research Program of the Oﬃce of Basic Energy Sciences at the U.S.Department of Energy under Grant No.DE-FG03-86ER13606,and by a grant from the University of California Institute for M´e xico and the United States (UC MEXUS)and the Consejo Nacional de Ciencia y Tecnolog´ıa de M´e xico (CoNaCyT).A.H.R.acknowledges support from Millennium Initiative,Conacyt-Mexico,under Grant W-8001.I.M.S.acknowledges the hospi-tality of the University of Barcelona under the CEPBA grant,as well as partial ﬁnancial support by the Fonds der Chemischen Industrie.[1]G.E.Poirier and E.D.Plyant,Science 272,1145(1996);T.Yokoyama et al.,Nature (London)413,619(2001);K.Ho,J.Chem.Phys.117,11033(2002);R.M.Tromp and J.B.Jannon,Surf.Rev.Lett.9,1565(2002).T.Ala-Nissila,R.Ferrando,and S.C.Ying,Adv.Phys.51,949(2002).[2]J.Wecksesser et al.,Surf.Sci.431168(1999);J.Weckesser,PhD Thesis,Swiss Federal Institute of Tech-nology,Laussane (2000).[3]M.Schunack et al.,Phys.Rev.Lett.88,156102(2002).[4]G.Ertl and H.-J.Freund,Phys.Today 52,32(1999).[5]W.D.Luedtke and ndman,Phys.Rev.Lett.82,3835(1999).[6]D.Cowell Senft and G.Ehrlich,Phys.Rev.Lett.74,294(1995);T.R.Linderoth et al.,Phys.Rev.Lett.78,4978(1997); A.P.Graham et al.,Phys.Rev.B 56,10567(1997);S-M Oh et al.,Phys.Rev.Lett.88,236102(2002).[7]K.D.Dobbs and D.J.Doren,J.Chem.Phys.97,3722(1992);R.Ferrando,R.Spadacini,and G.E.Tommei,Phys.Rev.E 48,2437(1993);L.Y.Chen,M.R.Baldan,and S.C.Ying,Phys.Rev.B 54,8856(1996);J.L Vega,R.Guantes,and S.Miret-Art´e s,Phys.Cem.Chem.Phys.4,4985(2002);R.Guantes et al.,J.Chem.Phys.119,2780(2003).[8]M.F.Shlesinger,G.M.Zaslavsky,and J.Klafter,Nature363,31(1993).[9]J.Klafter and G.Zumofen,Phys.Rev E 49,4873(1994).[10]J.L.Vega,R.Guantes,and S.Miret-Art´e s,J.Phys.Condens.Matter 14,6193(2002).[11]R.Guantes,J.L.Vega,and S.Miret-Art´e s,Phys.Rev.B 64,245415(2001).[12]A.Gross,Surf.Sci.Rep.31,235(1998).[13]P.H¨a nggi,P.Talkner,and M.Berkovec,Rev.Mod.Phys.62,251(1990).[14]J.M.Sancho,A.H.Romero and K.Lindenberg,J.Chem.Phys.109,9888,(1998).[15]J.Klafter and G.Zumofen,Physica A 196,102(1993).[16]J.Garc ´ıa-Ojalvo and J.M.Sancho,Noise in Spatially Ex-tended Systems (Springer,New York,1999).[17]H.A.Makse,S.Havlin,M.Schwartz,and H.E.Stanley,Phys.Rev.E 53,5445(1996);E.Koscielny-Bunde,A.Bunde,S.Havlin,E.Roman,Y.Goldreich,and H.J.Schellnhuber,Phys.Rev.Lett.81,729(1998).[18]A.H.Romero and J.M.Sancho,p.Phys.156,1(1999);A.H.Romero,J.M.Sancho,and K.Lindenberg,Fluct.and Noise Lett.2,L79(2002).[19]A.H.Romero and J.M.Sancho,Phys.Rev.E 58,2833(1998).[20]casta et al.,in preparation.。

主观社会地位与身心健康评述

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结果-SSS考虑了 SES法解释的社会和心理因-如果考
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主观社会地位可能导致抑郁性思维-在对拉丁裔年轻
人的一项研究中冋，与高主观社会地位的情况下相
比,参与者
，在主观社会地位的况下，自心和力
量显下降-可能反映了主观社会地位与心理健康关系
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测牛血清白蛋白

Multiwalled carbon nanotubes-ceramic electrode modiﬁed withsubstrate-selective imprinted polymer for ultra-trace detection of bovine serum albuminBhim Bali Prasad n ,Amrita Prasad,Mahavir Prasad TiwariAnalytical division,Department of Chemistry,Faculty of Science,Banaras Hindu University,Varanasi-221005,Indiaa r t i c l e i n f oArticle history:Received 21June 2012Received in revised form 23July 2012Accepted 25July 2012Available online 17August 2012Keywords:Molecularly imprinted polymer Porogen-waterBovine serum albuminMultiwalled carbon nanotubes-ceramic electrodeDifferential pulse voltammetrya b s t r a c tThis study describes the synthesis of a new class of substrate-selective molecularly imprinted polymer.This involved tetraethylene glycol 3-morpholin propionate acrylate (functional monomer)and bovine serum albumin (template)for polymerization in aqueous condition,using ‘‘surface grafting-from ’’approach directly on a vinyl exposed multiwalled carbon nanotubes-ceramic electrode.The analyte recapture at pH 6.8in aqueous environment simultaneously involved hydrophobically driven hydrogen bonds and ionic interactions between negatively charged bovine serum albumin and positively charged imprinted nanoﬁlm.The selectively encapsulated bovine serum albumin ﬁrst gets reduced at À0.9V and then oxidized within the cavity,without getting stripped off,to respond a differential pulse voltammetry signal.The limit of detection [0.42ng mL À1(3s ,RSD r 1.02%)]obtained was free from any cross-reactivity and matrix complications in aqueous,pharmaceutical,serum,and liquid milk samples.The proposed sensor can be used as a practical sensor for ultra-trace analysis of bovine serum albumin in clinical settings.&2012Elsevier B.V.All rights reserved.1.IntroductionBovine serum albumin (BSA)is one of serum albumins that attract many biochemical applications.It is a major component of bovine plasma (5g/100mL)and plasma accounts for about 40%of the body pool of albumin (Hilger et al.,1996).It is used as a stabilizing agent in enzymatic reactions and as a carrier protein in many vaccines and medicines (Balen,2002).On exposure to BSA due to consumption of bovine milk and meat,its affects are similar as that of a prime allergen (Restani et al.,2004).Although great effort has been made to reduce exposure to BSA in pharmaceutics to eliminate the threat of bovine spongiforum encephalopathy,least attentions have been paid to comprehend the human immune response owing to the lack of fool-proof immunological methods for the direct evaluation of either BSA or anti-BSA antibodies.A number of anti-rabies vaccines [Semple Vaccine (ARV),Puriﬁed Vero Cell Rabies Vaccine (PVRV-Verorab and Abhayrab),and Puriﬁed Chick Embryo Cell Vaccine (PCEC-Rabipur)]have BSA content in ppb (ng mL À1)level.On account of some known complications of neurological accidents and allergic reactions (Chakravaty,2001),it becomes imperative for quality testing of each batch of these vaccines beyond the statuaryobligations.BSA content should be less than 50ng mL À1per human dose according to WHO standards (Deshmukh et al.,2004).Several diseases like a rare kidney disease called membra-nous naphropathy (Debiec et al.,2011),bovine spongiforum encephalopathy (Deshmukh et al.,2004),insulin dependent diabetes mellitus (Persaud and Barranco-Mendoza,2004),and crutzﬁeld–jacob (Brown,2005),are known that may be developed due to anticipated BSA exposure to human.Therefore,the detec-tion of BSA has become a wide area of research in immunology and bio-analytical studies.Extensive investigations have been reported for the determi-nation of BSA that include ﬂuorimetry (Sun et al.,2008),quartz crystal microgravimetry (Lin et al.,2004),reverse-phase high performance liquid chromatography (RP-HPLC)(Hamidi and Zarei,2009),direct electroanalysis (Chiku et al.,2008a ),and biosensor detection (Zhang et al.,2012).However,some of these methodologies needed extensive sample pretreatment,while others suffered from low selectivity,poor sensitivity,and high instrumentation.Electrochemical detection of higher non-metal proteins (e.g.,albumin)is reportedly very less.This is due to the apparent complexity and strong adsorption of protein on the electrode surface which may lead signal depression to be unpre-dictable and irreproducible.Many molecularly imprinted poly-mers (MIPs)have been developed for BSA (Kryscioa and Peppasa,2012;Ran et al.,2012;Gai et al.,2011;Zhang et al.,2010),without revealing analytical aspects.Furthermore,the imprintingContents lists available at SciVerse ScienceDirectjournal homepage:/locate/biosBiosensors and Bioelectronics0956-5663/$-see front matter &2012Elsevier B.V.All rights reserved./10.1016/j.bios.2012.07.080nCorresponding author.Tel.:þ919451954449;fax:þ915422268127.E-mail address:prof.bbpd@ (B.B.Prasad).Biosensors and Bioelectronics 39(2013)236–243solvents(porogens)for MIP development routinely being used were organic solvents that might unfold the native BSA,even at pre-polymerization stage.Insofar as MIP-based sensors(Chen et al.,2012;Yu et al.,2010)dealing ultra-trace analysis of BSA are concerned,there were some false-positive contributions with considerable amount of non-speciﬁc interferences and cross-reactivity.Although the recent seminal work of surface imprinted chitosan coated multiwalled carbon nanotubes(MWCNTs)-based biosensors(Chen et al.,2012)revealed a high level of sensitivity, unfortunately it was found stable only at41C for15day.Thus, this cannot be recommended as a practical sensor for in-ﬁeld and clinical settings.MIPs are synthetic antibody mimics,formed by cross-linking of organic(or inorganic)polymers in the presence of an analyte (template),which yield recognitive polymer networks with speciﬁc binding pockets for the biomolecules.Considering the incompat-ibility between the protein and organic solvents and moreover, its unfolding(denaturation)in harsh chemical conditions,the substrate(whole protein)imprinting in biological benign condi-tions,maintaining the physiological status of protein,is rather challenging.Protein imprinting in neutral aqueous condition might be an alternative that has,however,been drawn limited attention till date,primarily because of water competition toward hydrogen bonding interactions(Lin et al.,2009;Yang et al.,2011).We are of the opinion that the concerted effects of hydrophobically driven hydrogen bonding and electrostatic interactions might rescue the situation and a stable MIP-template adduct formation in aqueous condition could be feasible for the substrate-selective imprinting of entire protein molecule,without its denaturation in the experi-mental conditions.Besides,surface imprinting can also be imbibed in such work to avoid the protein entrapment in the polymer matrix and to facilitate the analyte mass-transfer without any impediment or blocking effect(Turner et al.,2006).We have adopted this approach for theﬁrst time for BSA imprinting where imprinted chains were grown via free radical polymerization, directly on the surface of a vinyl exposed MWCNTs–ceramic electrode(MWCNTs-CE).For MIP development in aqueous med-ium,both monomer and cross-linker ought to be soluble in water. In the present work,a typical monomer,tetraethylene glycol-3-morpholine propionate acrylate(TEGMPA),and a cross-linker, diacryloyl urea(DAU),were synthesized,which are water-soluble.TEGMPA is consisted of two kinds of functional group: one is the acrylate,which could be polymerized by free radical chain growth process,linking the TEGMPA in the polymer network and the other the30amine which readily abstracts a proton from water in neutral condition.Nevertheless,taken an excess amount of TEGMPA,may lead to the generation of corresponding free radical,after reaction with ammonium persulphate(APS,initiator). This species may serve as a co-initiator(Wu et al.,2006;Yu et al., 2009)to expedite the polymerization process.The objective of such fabrication is to develop a water-compatible,highly sensitive,and selective tool for the detection of BSA in real samples.2.Experimental2.1.ReagentsAll chemicals were of analytical reagent grade and used without further puriﬁcation.Acryloyl chloride(AC),urea,BSA, and APS,were purchased from Loba Chemie(Mumbai,India). 3-(trimethoxysilyl)propyl methacrylate(TMPM),tetraethylene glycol diacrylate(TEGDA),morpholine,MWCNTs(internal dia-meter2–6nm,outer diameter10–15nm,length0.1–10m m, and purity490%),and interferents were obtained from CDH (Delhi,India)and Aldrich(Steinheim,Germany).Phosphate buffer solution(PBS,pH 6.8,ionic strength0.1M)was used as a supporting electrolyte.Standard stock solution of BSA (500m g mLÀ1)was prepared using deionized triple-distilled water(conducting range(0.06–0.07)Â10À6S cmÀ1).Human blood serum samples were collected from a local pathology laboratory and stored in a refrigerator at$41C,before use.The pharmaceutical sample analyzed was Rabipur(Rabies vaccine).2.2.ApparatusAll voltammetric measurements were carried out with a polarographic analyzer/stripping voltammometer[model264A, EG&G Princeton Applied Research(PAR),USA]in conjunction with an electrode assembly(PAR model303A)and a X–Y chart recorder(PAR model RE0089).A conventional three-electrode system was adopted where platinum wire was used as an auxiliary electrode,saturated Ag/AgCl electrode as a reference electrode,and MIP-modiﬁed MWCNTs-CE as a working electrode.Chronocoulometry measurements were performed on an electro-chemical analyzer(CH instruments USA,model1200A).FT-IR and NMR spectroscopic measurements were performed by Varian3100 FT/IR(USA)and JEOL AL300FT-NMR(Japan),respectively.Morpho-logical studies of bare and MIP-modiﬁed electrode surface were made using scanning electron microscope(SEM)[JEOL,JSM,Netherlands, Model840A].All experiments were carried out at25711C.2.3.Synthesis of TEGMPASynthesis of TEGMPA is similar to that of ethylene glycol 3-morpholine propionate acrylate(Yu et al.,2009).For this a mixture of1.3mL of morpholine(15mmol)dissolved in7.5mL methanol was added drop-wise in TEGDA(1.36mL,15mmol)at 0–51C,under magnetic stirring in nitrogen atmosphere.FT-IR was used to monitor the completion of the reaction.When the N–H peak at3515cmÀ1was disappeared,methanol was removed by rotatory evaporation.The product so obtained was identiﬁed by1H NMR as follows:1H NMR(D2O):d6.1(1H),d5.8(1H),d 6.4(1H),d3.7(4H),d(4H),d3.6(4H),d4.2(4H),d3.5(8H), d2.6–2.8(4H).2.4.Synthesis of cross-linker(1,3-diacryloyl urea,DAU)Preparation and characterization of cross-linker,DAU,are described elsewhere(Prasad et al.,2010).In brief,to alkaline solution of urea(1.8g urea/15mL1.0M NaOH)4.87mL AC was added drop-wise and heated for20min at801C.A crude white product was separated out(the completion of reaction was indicated by the disappearance of the pungent smell of AC)and this was re-crystallized with ethanol.2.5.Electrode preparationMWCNTs render biocompatibility to the ceramic electrode, besides inculcating electro-conductivity.Furthermore,CNTs are homogeneously dispersed in ceramic(sol–gel)matrix to improve stability as compared to pest or composite electrode.MWCNTs-CE surface is more amenable to‘‘surface grafting from’’approach for the growth of a nanometer thin MIPﬁlm(Prasad et al.,2011).Also,this electrode is reportedly best amongst other modiﬁed electrodes (carbon CE,carbon CE modiﬁed with MWCNTs)in terms of providing lower charging current and hence better signal/noise ratio(Prasad et al.,2011).For MWCNTs-CE preparation in this work, 1.0mL ethanol,1.0mL TMPM,0.5mL water,and10.0m L of0.1M HCl were mixed together for30min to obtain sol–gel,followed by a hand on mixing with100mg MWCNTs.The suitable amount of this homo-genized mixtures wasﬁlled in a glass tube(outer diameter0.4cm,B.B.Prasad et al./Biosensors and Bioelectronics39(2013)236–243237length 3.0cm)under physical pressure,and then left to dry for 48–72h at room temperature.Electrical contact was achieved by insert-ing a copper wire through the top via open tip of the glass tube.The bottom tip was ﬁrst smoothened and polished with an emery paper to obtain a bright surface and then rinsed with water.As many as three vinyl exposed MWCNTs-CEs were obtained from the entire reaction mixture.In order to optimize the concentration of double bonds at the surface of electrode,four additional MWCNTs-CE were prepared using MWCNTs (100mg)and the varying amount of sol–gel (50,100,150,and 200m L).The amount of double bonds at the vinyl exposed MWCNTs-CE surface was determined by a catalytic bromine addition reaction between Br 2(KBrO 3/KBr in acidic condition)and the prevalent double bonds catalyzed by HgCl 2.The excess Br 2was evaluated by the standard method of iodometric titration.This led the determination of actual amount of Br 2consumed by double bonds that is equivalent to the concentration of vinylic double bonds at the electrode surface [For details vide Supplementary Data Section (S.1)].2.6.Grafting of MIP on the exposed vinyl groups of MWCNTs-CE For grafting MIP on to the vinyl exposed MWCNTs-CE (Scheme 1),the pre-polymerization mixture [template (BSA,0.001mmol/2mL TDW),monomer (TEGMPA,0.02mmol/1.0mL TDW),cross-linker (DAU,0.2mmol/1.0mL TDW),and APS (10m L,20%w/v)]was mixed with 15.0mg of MWCNT-COOH.The whole content was purged with N 2gas for 10min,and 10m L of this solution was spin coated on the MWCNTs-CE surface at 1500rpm for 20s.The electrode was kept in a UV chamber at 381C for 3h (with intermittent heating at 10min interval)to initiate free radical polymerization.Note that continuous exposure of electrode in UV chamber was avoided just to safeguard against denaturation of protein.Similar procedure was also followed to prepare the non-imprinted (control)polymer i.e.,NIP-grafted electrodes in the absence of template (BSA).Template molecules were retrieved from the polymeric (MIP-template adduct)ﬁlm by stirring the modiﬁed electrode into 0.1M NaOH for 30min.The complete template removal was ensured until no voltammetric response of the template was noticed.2.7.Voltammetric procedureFor electrochemical measurement,the analyte was ﬁrst accumu-lated with stirring for 60s (accumulation time)in an open circuitand then after a negative potential of 0.9V vs.Ag/AgCl was imposed.After 15s equilibration time,differential pulse voltammetric (DPV)run was scanned from À0.7V to þ0.7V vs.Ag/AgCl using pulse amplitude of 25mV,pulse width 50ms,and scan rate 10mV s À1.Cyclic voltammograms (CVs)were also recorded in the potential window À0.7V to þ0.7V at different scan rates (10–200mV s À1).Since oxygen did not inﬂuence the voltammetry of analyte,any deaeration of the cell content was not required.All DPV runs for each concentration of test analyte were quantiﬁed using the method of standard addition.3.Results and discussion3.1.Evaluation of graft efﬁciency and its effect on surface imprinting The concentration of the double bonds per unit area of electrode surface (E ,mol/cm 2)is used to evaluate the graft efﬁciency,and this can be deﬁned as E ¼ðV b ÀV s ÞC2Að1Þwhere V b and V s,are the volumes (L )of Na 2S 2O 3standard solution consumed in the blank and sample experiments (in the absence and presence of electrode),respectively,C is the concentration of Na 2S 2O 3standard solution (mol/L),and A is the area of MWCNTs-CE (cm 2).From the above equation,graft efﬁciencies were calculated for four different electrodes obtained using varying amount of TMPM as shown in Fig.S1.A .This depicted an increase in graft efﬁciency with the increase of TMPM.Interestingly,of all electrodes prepared with different amounts (50m L,100m L,150m L,200m L)of TMPM and duly modiﬁed with MIP,MIP-modiﬁed MWCNTs-CE carrying 150m L of TMPM at prelimin-ary layer responded a highest current (Fig.S1.B )for BSA (7.59ng mL À1).At the surface of this MIP-modiﬁed MWCNTs-CE,optimized vinyl double bonds by the virtue of TMPM grafting might have induced the selective and high occurrence of imprinting polymerization,leading to form thin MIP layer consisted of max-imum number of recognition sites.Any amount lower than 150m L TMPM and thereby the less amount of vinyl groups led to the low efﬁciency of imprinting polymerization,at the surface of electrode.On the contrary,vinyl groups were so crowded at MWCNTs-CE surface that the excessive amount of TMPM (4150m L)always resulted in a low occurrence of imprinting polymerization,duetoScheme 1.Schematic representation of MIP-modiﬁed MWCNTs-CE fabrication.B.B.Prasad et al./Biosensors and Bioelectronics 39(2013)236–243238the possible steric hinderance or self-polymerization of surface vinyl groups.Hence,MWCNTs(100mg)mixed with150m L of TMPM might be considered to be the best optimized composition to obtain MWCNTs-CE for polymer chain growth with efﬁcient imprinting.3.2.Polymer characteristicsVinyl exposed MWCNTs-CE inherited a unique characteristics provided by the sol–gel matrix with excellent biocompatibility and CNTs with attractive electrochemical features.Herein,TMPM is sandwiched between MWCNTs and MIP;TMPM molecules on the one hand interacted with the hydrophobic side walls of nanotubes while on the other side covalently anchored the imprinted polymer network(Scheme1).The parts of nanotubes shielded by a chain of silicate particles,however,may not be electrochemically accessible. Nevertheless,the exposed(unshielded)parts of the nanotubes still remain intact and are readily accessible for solution species to serve as nano-electrodes(Gong et al.,2005).The ratio of template,mono-mer,and cross-linker needs to be optimized since the recognition ability of imprinted polymer is primarily dependent on both the print molecule and functional precursors of the polymer.Different tem-plate to monomer molar ratios(1:10,1:20,1:40,1:60,and1:80)were tested on MWCNTs-CEs;the optimized template-monomer stoichio-metry of1:20yielded a maximum DPV response for a known concentration(9.95ng mLÀ1)of BSA(Fig.S2.A).There are reportedly 18net negative charges on each BSA molecule(Carter and Ho,1994) in neutral medium.Consequently,functional monomers carrying the equivalent amount of positive charges are minimally required for charge compensation to ensure a stable self assembly of BSA-TEGMPA complex in pre-polymer mixture.Accordingly,this complex with1:20stoichiometry,[BSA.TEGMPA20]þþ,eventually led the pro-duction of a cationic polymer motif,[BSA.TEGMPA20]2nþ,for sub-strate imprinting on MWCNTs-CE surface.Any amount of TEGMPA less than0.02mmol revealed instability of the system responding lower current due to the increased heterogeneity in the structure. Furthermore,too many functional monomers excess than requisite for self assembly may lead non-speciﬁc analyte binding.The cross-linker amount could be an aided factor toward the stability of protein–monomer complex.In this work,the maximum development of DPV current response occurred when the cross-linker(DAU) amount0.2mmol was used with1:20complex.This is due to the improved stabilization of binding sites.The further increase of cross-linker should be avoided,since this may impede the template diffusion across the MIP motif,as was evinced by the declined response of BSA encapsulation(Fig.S2.B).In the polymerization, APS served as an initiator while monomer acted as an accelerator of the polymerization process in the capacity of co-initiator on abstrac-tion of proton and generation of initiating free radicals thereof,as shown in Fig.S3(Yu et al.,2009).Polymerization conditions have drastic impact on protein imprinting.The concerted effect of initiator and co-initiator in the form of two generated free radicals(Fig.S3) triggered the polymerization kinetics at low polymerization tempera-ture that helped avoiding protein denaturation on exposure to UV light.An optimum of381C polymerization temperature for3h,on intermittent exposure to UV light for10min interval,resulted in electrode modiﬁcation for optimum DPV current response(Fig.S2.C). Exceeding temperature above381C(Fig S2.D)might have induced conformational changes in BSA molecule(Takeda et al.,1989)that resulted in decreased DPV current.Also,at temperature lower than 381C,the polymerization process required longer time for complete reaction.3.3.Spectral and surface characterizationFT-IR(KBr)spectra(Fig.S4)of template,monomer,MIP,and MIP-adduct are comparatively examined to support the proposed binding mechanism(Fig.1)in aqueous medium.BSA is a large guest molecule with several exposed reactive functionalities,at its surface,for binding with the host MIP.Such bindings are suggested on the basis of downward shifts of IR bands of participating key groups.[For details,vide Supplementary Data Section S.2].An insight into the surface morphology of the modiﬁed surface of MWCNTs-CE was feasible through SEM images(Fig.2).The bare MWCNTs-CE showed distinctly visible nanotubes(Fig.2A). Surface of MIP-BSA adduct-modiﬁed MWCNTs-CE is relatively compact(Fig.2B).Upon template retrieval from this,the MIP-modiﬁed electrode(Fig.2C)revealed rather a rough surface and thereby a high surface area ofﬁlm,which is beneﬁcial for the adsorption of proteins.Fig.2D displays the side view of MIP modiﬁed MWCNTs-CE reﬂecting68.1nm thickness of coating layer[vide Supplementary Data Section S.3].3.4.Electrochemical behaviorFig.3A shows CV runs of1.99ng mLÀ1of BSA,recorded within the potential windowÀ0.7V toþ0.7V(vs.Ag/AgCl),after analyte accumulation for60s and subsequently exposing the MIP-modiﬁed MWCNTs-CE sensor atÀ0.9V for15s equilibration time.The bare(unmodiﬁed)electrode,however,responded only at a higher scan rate(Z100mV sÀ1)for the higher concentration of BSA(Z20.0ng mLÀ1),with broader and ill deﬁned features (Fig.3A,inset).The accumulation of analyte was favored owing to strong electrostatic interaction between positively charged MIP ﬁlm and negatively charged BSA molecule,irrespective of nega-tive accumulation potential rÀ0.9V imposed.The polarity on the modiﬁed MWCNTs-CE could drastically be altered on applying more negative potential(4À0.9V)which restricted analyte binding.BSA electrochemistry is reportedly conﬁned with the mini-mum of three redox active amino acid residues[Cystein(CYS),Fig.1.Suggested binding mechanism of BSA via multiple point electrostatic and hydrogen bonding interactions(BSA:monomer molar ratio1:20;for the sake of brevity,only a few monomeric units are shown)with the MIP motif.B.B.Prasad et al./Biosensors and Bioelectronics39(2013)236–243239tyrosine,and tryptophan (TRP)](Chiku et al.,2008b ).Besides,BSA redox reaction is also expected to take place on the sulphur double bonds in typical cases (Shao et al.,2005;Stankovich and Bard,1978).In the present instance,the electro-active groups of CYS,tyrosine and TRP are bound through H-bondings within the MIP cavities (Fig.1),and thus not free to take part in redox process in bound condition.Notably,BSA molecules are not stripped off the cavities owing to the strong electrostatic attraction between positively charged electrode and negatively charged template molecules on anodic scan.Since MIP particles are covalently linked with MWCNTs-CE,an apprehension of leaching of MIP adduct is ruled out during anodic scan.Accordingly,only option left for BSA oxidation is solely dependent upon the disulphide bonds.Disulphide bonds exposed at the surface of BSA were reduced initially at accumulation stage,given negative potential for the reduction.This process may thus be written as follows (Shao et al.,2005):Accumulation stage:(R–S ¼S–R)solution -(R–S ¼S–R)adsorbedCathodic reduction stage:(R–S ¼S–R)adsorbed þ2H þþ2e À-(R–SH–SH–R)adsorbed (at À0.9V)Anodic oxidation stage:(R–SH–SH–R)adsorbed -(R–S ¼S–R)adsorbed þ2H þþ2e ÀThe quasi-reversibility nature of the peaks is suggested by the corresponding D E p range,varying from 0.075V to 0.300V with the increase of scan rates (10–200mV s À1),and the value of I pa /I pcgreater than unity.The broad peak width at all scan rates indicates the strong adsorption of both reduced and oxidized species;pre and post-adsorption peaks are concealed within the drawn-out peaks (feeble pre-adsorption peaks,however,seen at high scan rates).The quasi-reversibility for this process was also conﬁrmed from the different slopes of I pa vs.n 1/2and I pc vs.n 1/2proﬁles as shown below:I pa ¼ð2:8970:21Þn 1=2þðÀ7:4971:84Þ,R 2¼0:98ð2ÞI pc ¼ð1:8970:15Þn 1=2þðÀ4:9371:34Þ,R 2¼0:98ð3ÞUnder these conditions of quasi-reversibility,it may be possi-ble to study the kinetics of the electrode reaction.Accordingly,the separation of peak potential,D E p ,should be a measure of the standard rate constant (K 0)for electron transfer process.These D E p values were introduced in the working curve described by Nicholson (1965)for obtaining the transfer parameter,c ,and then the value of K 0was estimated according to the following equation (Pad and Leddy,1995).C ¼K 0ðD oxi =D red Þa =2ðD oxi nFv =RT Þð4ÞTo estimate K 0from Eq.(4),the diffusion coefﬁcient (D )(assuming D ox ¼D red ¼D )was obtained from the chronocoulometry experiment.According to the integrated Cottrell equation (Bard and Faulker,2001),the relationship between Q and t 1/2(Anson plots)can be described as follows:Q ¼2nFACD 1=2t 1=2p À1=2þQ dl þQ ads ð5ÞQ ads ¼nFa G 0ð6ÞFig.2.SEM images of (A)unmodiﬁed MWCNTs-CE,(B)MIP-adduct modiﬁed MWCNTs-CE,(C)MIP modiﬁed MWCNTs-CE and (D)side view of modiﬁed MWCNTs-CE.B.B.Prasad et al./Biosensors and Bioelectronics 39(2013)236–243240where A is area of electrode (0.0827cm 2),C is the concentration (1.99ng mL À1)of BSA,Q dl is the double layer charge,Q ads is the faradic oxidative charge,and G 0is the surface coverage.For bare and modiﬁed electrodes,Q dl and total charge (Q dl þQ ads )were estimated from the respective intercepts of the Anson plots (Q and t 1/2)in the absence and presence of BSA.Accordingly,Q ads was calculated as 8.79Â10À6.Surface coverage can be obtained in terms of number of electron ‘n ’by the equation deﬁning Nerstian adsorbent layer (Hassen et al.,2007):I p ¼n 2F 24RT"#G 0A nð7ÞAccordingly,n and G 0were obtained to be 1.95and 5.59Â10À10mol cm À2,respectively.This reﬂects total surface coverage of speciﬁcally bound analyte (4.6Â10À11mol or 2.77Â1013molecules)to MIP cavities (each molecule per cavity).The slope of the Anson plot (0.346Â10À3m C s À1)revealed an estimate of 2.55Â10À2cm 2s À1for D .Substituting the D value (D ox ¼D red )the K 0values at different scan rates were calculated from Eq.(4)for different values of c [1.75(10mV s À1),0.17(20mV s À1),0.11(50mV s À1)]as 0.437,0.060,and 0.061cm s À1(mean K 0¼0.186cm s À1).The decrease in K 0represents sluggish kinetics of electron-transport for BSA oxidation with the increase of scan rate,under the adsorbed state of analyte in the domain of molecular cavities of imprinted polymer.Insofar as the sensitivity of the measurement is concerned,the DPV technique is better than CV at the scan rate,10mV s À1.This is because of the fact that an approximately 3.5-fold higher current is obtained in the sufﬁcient time scale of measurement,using pulse amplitude 25mV and pulse width 25ms.DPV runs (Fig.3B)showed symmetrical peaks for BSA detection in aqueous and real samples (serum,milk,and vaccine)with the MIP modiﬁed electrodes,without any matrix complication.NIP-modiﬁed electrodes did not respond to BSA in aqueous and pharmaceutical samples.However,some non-speciﬁc adsorption of BSA could be seen on NIP-modiﬁed electrode in serum samples which was easily removed simply by water washing (n ¼3,0.5mL).The reproducible regeneration of modiﬁed electrodes for the next use was feasible adapting the method of template retrieval (vide Section 2.6).Accordingly,the used electrode was regenerated by dipping in 0.1M NaOH solution for 30min,under stirred condition.The overall renewal of the modiﬁed electrode was conﬁrmed by DPV until no template residue was left in the modiﬁed ﬁlm to respond any voltammetric current.Any deformation of MIP cavities was ruled out after regeneration,as the renewed sensor always responded quantitative (100%)response of BSA in aqueous medium.In this work,any single modiﬁed electrode could be used for as many as 60consecutive runs,with quantitative recoveries,after regeneration by the method of template extraction (Fig.S5).Further-more,the reproducibility on a single electrode,which was renewed after each run,was examined by obtaining multiple DPV runs (Fig.3B,run c)for BSA (1.99ng mL À1)in aqueous medium.Insofar as electrode to electrode variation is concerned,a parallel measurement for BSA (2.89ng mL À1)in blood serum on three modiﬁed electrodes,prepared in the same ways in different batches,responded quantita-tive recoveries with RSD 1.5%(Fig.3B,run f).This indicates precision of the result as well as reproducibility in MIP sensor development.Notably,the multiple runs (Fig.3B,runs c and f)both in aqueous and blood serum samples obtained with the regenerated MIP-sensor,show requisite ruggedness of the sensor without revealing any medium effect and false-positives.3.5.Analyte adsorption behaviorThe Langmuir equation (Eq.(8))provides a relationship between the concentration (C )of BSA solution,and the amount of BSA adsorbed on the surface (!0)(Smiechowski et al.,2006):CG¼1B ads GmaxþCGmaxð8Þwhere B ads is the adsorption coefﬁcient and !max represents the maximum amount of protein that can adsorb on the surface.Thus,a linear equation C/G 0¼(0.003470.0003)Â1011C þ(0.046670.0029)(R 2¼0.984),for the plot of C/G 0vs.C is obtained.The intercept (equivalent to slope/B ads )of this equation suggests an estimate of adsorption coefﬁcient (B ads )to be 7.29Â109L mol À1.The Gibbs free energy of adsorption,D G ads can be estimated using equation (Wright et al.,2004):B ads ¼155:5exp ÀD G adsRTð9Þwhere 55.5represents the molar concentration of water (mol L À1)which was used as the solvent.The large negative value of D G ads (À66.23KJ mol À1)indicates spontaneous analyte adsorption on the MIP surface.The value of D G ,in the present case,is higher to that reported earlier for proteins (Smiechowski et al.,2006).3.6.Optimization of analytical parametersAs observed in CV measurement,the extent of analyte accu-mulation was negligibly affected by the negative polarization of modiﬁed MWCNTs-CE and accumulation was effective even atanFig.3.(A)CV runs of BSA (1.99ng mL À1)at different scan rates:(a)blank,10,(b)10,(c)20,(d)50,(e)100,and (f)200mV s À1at MIP modiﬁed MWCNTs-CE and unmodiﬁed MWCNTs-CE (inset).(B)DPV responses on MIP modiﬁed MWCNTs-CE run a for blank,runs c and d for BSA (1.99and 6.99ng mL À1)in aqueous medium,runs (f)and (g)for BSA (2.89and 4.91ng mL À1)in serum,run (i)for BSA (4.48ng mL À1)in vaccine,run (k)for BSA (5.25ng mL À1)in milk,runs (b),(e),(h),and (j)for BSA (20.0ng mL À1)at NIP modiﬁed MWCNTs-CE in aqueous,serum,pharmaceutical,and milk samples,respectively.B.B.Prasad et al./Biosensors and Bioelectronics 39(2013)236–243241。

Measurement of the flow structures in the wakes of

Measurement of theﬂow structures in the wakes of different typesof parachute canopiesSylvio Pasqualini1·Zheyan Jin1,2·Zhigang Yang2Received:28December2016/Revised:11April2017/Accepted:28June2017/Published online:14September2017©The Chinese Society of Theoretical and Applied Mechanics;Institute of Mechanics,Chinese Academy of Sciences and Springer-Verlag GmbH Germany2017Abstract We measuredﬂow structures with stereoscopic particle image velocimetry(stereo-PIV)in the turbulent wakes of three parachute canopies,which had the same sur-face area,but different geometries.The tested parachute canopies included ribbon canopy,8-branches canopy,and cross canopy.The obtained results showed that the geome-try of the parachute canopies had signiﬁcant inﬂuences on theﬂow structures in the wakes of these three canopies.In addition,the variation of Reynolds number did not lead to a dramatic change in the distributions of velocity,vorticity, Reynolds stress,and turbulent kinetic energy.Keywords Parachute canopies·Wake structures·Particle image velocimetry1IntroductionAs a type of aerodynamic decelerator,parachutes have been widely used in life-saving and recovery systems.Based on their geometries,parachutes can be classiﬁed into round parachutes,cross-type parachutes,and ribbon parachutes. Because most parachutes use fabric canopies,the fabric ﬂexibility results in apparent changes in the canopy geometry B Zheyan Jinzheyanjin@1School of Aerospace Engineering and Applied Mechanics, Tongji University,Shanghai200092,China2Shanghai Key Lab of Vehicle Aerodynamics and Vehicle Thermal Management Systems,Shanghai201804,China during both inﬂation and terminal descent phases[1].More-over,because of the fabric permeability,small airﬂow can go through the canopy surface.The unsteadyﬂow in the wake, together with theﬂexible fabric canopy,leads to unavoid-ableﬂuid–structure interaction[2].Further insight into the ﬂowﬁelds in the wakes of theﬂexible canopies not only allows us to have a better understanding of the unsteady aero-dynamics pertinent to the parachutes,but offers important knowledge for scientists to develop superior parachutes as well[3].Through the years,scientists have carried out extensive investigations into the aerodynamic characteristics of dif-ferent types of parachutes[4–16].For example,Peterson et al.[7]reported a review on the characteristics of parachute canopies from deployment phase to terminal descent phase. Furthermore,Levin and Shpund[8]changed the geometry of the cross parachute canopies to optimize their aerodynamic performance.In their work,Stein et al.[9]numerically inves-tigated the interactions between two approaching parachute canopies in a cluster of parachutes.Also,Ya˘g iz et al.[10] reported the inﬂuence of the geometry of three parachute canopies on the tangential force coefﬁcient.In their work, Johari and Levshin[11]studied the interaction of a line vor-tex aligned with the axis of fully inﬂated parachute canopies. Then,Han et al.[12]proposed multi-node models to calculate the shape of full-ﬁlled cross parachutes.The study by Xue et al.[13]numerically investigated the effects of suspension lines on theﬂowﬁeld around a rigid supersonic parachute mode.In addition,Xue et al.[14]performed3-D simula-tions to investigate the supersonicﬂow over rigid parachute models and focused on the effects of the trailing distances and the ratio of the diameter of capsule to canopy.The work of Gao et al.[15]presented theﬂuid–structure interaction(FSI) phenomenon of a parachute duringﬁnite mass inﬂation with226S.Pasqualini,etal.Fig.1Conﬁguration of the parachute models.a Ribbon.b 8-branches.cCrossFig.2The parachute model and forebody support structure in the wind tunnellow speed and altitude.Moreover,Gao et al.[16]performed the inﬂation simulations of a full-scale model disk-gap-band parachute from the Mars Science Laboratory (MSL)mission.Fig.4Illustrations of the laser sheet arrangement behind the cross parachute canopy.a Position A.b Position BRecently,some researchers have used particle image velocimetry (PIV)to carry out the ﬂow ﬁeld measure-ments on several types of parachute models.For example,Desabrais [17]investigated the ﬂow ﬁeld in the wake of a ﬂexible generic round parachute canopy.Also,Wer-net et al.[18]obtained the velocity distributions of the shock locations during the canopy shock oscillations on a rigid supersonic parachute model.In their work,Schairer et al.[19]conducted unsteady ﬂow measurements intheFig.3Experimental setupMeasurement of theﬂow structures in the wakes of different types of parachute canopies227wake of a tension-cone decelerator in the subsonicﬂow. The study by Sengupta et al.[20]measured the velocity ﬁeld upstream of the Orion drogue parachute model.More recently,by using stereoscopic particle image velocimetry (stereo-PIV),Jin et al.[21]studied the effect of Reynolds number onﬂow structures in the wake of a circular parachute canopy.In addition,Jin et al.[22]also investigated the inﬂuence of the arm ratio of the cross canopy on the wake structures in terms of velocity,vorticity,and Reynolds stress.Although much research has been performed on differ-ent parachute models in the past[1–22],the quantitative measurements to reveal theﬂow structures in the wakes of the parachute canopies with different geometries,but the same surface area have not yet been investigated.Since parachutes can be classiﬁed into different types based on their geometries,it would be interesting to know the effects of the geometry of theﬂexible parachute canopies on the ﬂow structures in their wakes.In this study,an experi-mental investigation was carried out to characterize the ﬂow structures in the wakes of three different parachute canopies by using stereo-PIV technique.All these three parachute canopies had the same surface area.The objec-tive of this study is to further our understanding of the unsteady aerodynamics related to theﬂexible parachutecanopies.Fig.5Instantaneous vorticity results when Re=33,314.a Ribbon.b8-branches.c Cross(position A).d Cross(position B)228S.Pasqualini,et al.2Experimental2.1Parachute modelsThree parachute models were made of the solid cloth of a usedpersonnel parachute(Fig.1).These models had the same sur-face area(S=0.015m2)and were named ribbon canopy, 8-branches canopy,and cross canopy,respectively.The con-structed length,the thickness,and the cloth density of thesecanopies was150.0mm,0.1mm,and34.92g·m−2,respec-tively.The arm ratio(i.e.,AR=L/W,where L is the lengthand W is the width)of the cross canopy was measured to be2.10.Figure2shows the inﬂated canopy and the supportingmount at the test section of the wind tunnel.Nylon suspension lines were used to attach the canopy to a forebody.The num-ber of nylon suspension lines for ribbon canopy,8-branches canopy,and cross canopy was28,24,20,respectively.The detailed information of forebody,suspension lines,stainless steel rods,and retention line has been given in our previous studies[21,22].2.2Experimental setupThe present experimental investigation was performed in a low speed wind tunnel.During the experiments,the speed of the incoming airﬂow,U∞,changed from3.36to7.50m·s−1. By using the constructed length of the canopy as the char-acteristic length,the Reynolds numbers varied in the range 33,314 Re 74,362.The current experimental setupisFig.6Streamlines and the ensemble-averaged normalized z-component of the velocity(U z/U∞)with Re=33,314.a Ribbon.b8-branches.c Cross(position A).d Cross(position B)Measurement of theﬂow structures in the wakes of different types of parachute canopies229shown in Fig.3,which has been described in our previous study[21,22].It should be noted that the angle displacement arrangement with the Scheimpﬂug condition was used in the present stereo-PIV measurements.In addition,in the images obtained by the charge coupled device(CCD)cameras,each pixel represented an actual distance of0.095mm.The inter-ested readers are referred to Refs.[21,22]for details.3Results and discussionsIn this study,the room temperature was kept at(21.5±0.5)◦C,while the relative humidity of the surrounding air was held at(62.0±2.0)%.In order to avoid the laser lights reﬂected by the parachute canopies,we did not record theﬂowﬁeld information immediately downstream of the parachute canopies.In addition,as shown in Fig.3,the apex of the parachute was chosen to be the origin of the coordinate system.A parameter,R,was deﬁned as the con-structed radius,which was half of the constructed length (L).The region of interest was selected at a region where 0.22R x 1.85R and−1.4R y 0.9R.Figure4illus-trates the laser sheet arrangement behind the cross parachute canopy.Position A represents theﬂow over arm and posi-tion B represents theﬂow through gap.For each case,the image acquisition rate of the stereo-PIV measurement was chosen at4.0Hz and it was different from the frequency of the“breathing”phenomenon of the parachute canopies.InFig.7Ensemble-averaged normalized x-component of the velocity(U x/U∞)with Re=33,314.a Ribbon.b8-branches.c Cross(position A).d Cross(position B)230S.Pasqualini,et al.addition,a sequence of 350stereo-PIV images was captured for each case.By following the procedures of the previous studies [21,22],the normalized Reynolds stress (¯τ)and turbulence kinetic energy (TKE)were deﬁned,the uncertainties of,which were about 5%.In addition,the time-averaged pro-jected areas of these parachute canopies were obtained to be less than 105.0cm 2,which meant that the blockage ratios were less than 4.2%.Figure 5shows the instantaneous vorticity distributions in the wakes of different types of parachute canopies at Reynolds number of 33,314.For all the canopies,vortices of different intensities appeared in their wakes.However,the vortices in the ribbon canopy case were found to have less vorticity than those of the other cases.Such a phenomenon might be because of the many small oriﬁces distributed on the surface of the ribbon canopy.When air ﬂow penetrates the ribbon canopy,they create many small-scale jet ﬂows,which induce vortices with relatively lower intensity.Simi-lar to the observation in Ref.[6],for the cross canopy,a larger turbulent wake was found in the ﬂow through gap (position B)in comparison with the ﬂow over arm (position A).In our results,concentrated vorticity regions could be found near the x -axis,which were because of the existence of retention line and should be neglected.Figure 6shows the streamlines and ensemble-averaged normalized z -component of the velocity (U z /U ∞)distri-butions in the wakes of these three parachute canopies at Reynolds number of 33,314.For all cases,a recirculation zone formed in the wake,which was similar to that of the circular parachute canopy case [21].However,the recircu-lation zone in the wake of the ribbon canopy seemed to be totally different from those of the other cases.It occurred at a further downstream region than the others.In addi-tion,the recirculation zone of the ﬂow over the arm of the cross canopy (position A)was smaller than that of the ﬂow through the gap (position B).Moreover,the distributions of the z -component of the velocity of the ribbon canopy were also dramatically different from those of the other cases.Because of the inﬂuence of the gravity of thecanopies,Fig.8The transverse proﬁles of ensemble-averaged normalized x -component of the velocity with x =1.5R .a Ribbon.b 8-branches.c Cross (position A).d Cross (position B)Measurement of theﬂow structures in the wakes of different types of parachute canopies231the retention line might not hold the parachute canopies perfectly horizontal,which could result in the asymmetry of the recirculation zones in the wakes of these parachute canopies.The ensemble-averaged normalized x-component of the velocity results(U x/U∞)in the wakes of different kinds of parachute canopies at Reynolds number of33,314are shown in Fig.7.In order to better explain the results,Z U x=0was used to represent the velocity zone conﬁned by U x/U∞=0. Generally speaking,three features can be observed from these results.Firstly,the center of the velocity zone Z U x=0 of the ribbon canopy located further downstream than those of the other cases.Secondly,as for the cross canopy,the size of the velocity zone Z U x=0of theﬂow through gap(position B)was much larger than that of theﬂow over arm(position A).Thirdly,the size of the velocity zone Z U x=0of theﬂow at either position A or position B of the cross parachute in the present study was smaller than that of the circular parachute tested by Jin et al.[21].The possible reason for such a phenomenon might be due to that the cross shape allowed the airﬂow to move around more easily than the circular shape.In the present study,the transverse proﬁles of the vari-ables in the wakes of different kinds of parachute canopies at different Reynolds numbers were also obtained and ana-lyzed.For example,at location where x=1.5R,the transverse proﬁles of x-component of the velocity are shown in Fig.8.The results indicated that the effect of the Reynolds number on the transverse proﬁles of the x-component of the velocity was insigniﬁcant for all thesecanopies. Fig.9Ensemble-averaged normalized vorticity(ωz L/U∞)with Re=33,314.a Ribbon.b8-branches.c Cross(position A).d Cross(position B)232S.Pasqualini,etal. Fig.10The transverse proﬁles of ensemble-averaged normalized vorticity where x=1.5R.a Ribbon.b8-branches.c Cross(position A).d Cross (position B)In addition,the minimum values of the x-component of the velocity for the ribbon canopy case were generally lower than those of the other canopies.In addition,the transverse proﬁles were not symmetrical with respect to the x-axis,which corresponded to the results in Figs.6 and7.Figure9shows the ensemble-averaged normalized vortic-ity distributions(ωz L/U∞)in the wakes of these parachute canopies at a Reynolds number of33,314.For all cases, the majority of the vorticity appeared near the area where y≈−1.0R and decayed rapidly.As for the cross canopy, the concentrated vorticity region at position A was located closer to the x-axis when compared to that at position B. Near the x-axis,two parallel concentrated vorticity regions appeared,which were induced by the existence of retention line and should be neglected.However,the error induced by the existence of retention line was more obvious at position B(Fig.9d)than that at position A(Fig.9c). The possible explanation for this phenomenon might be that the combination of the unsteady wakeﬂow and the ﬂexible canopy produced unavoidableﬂuid–structure inter-action between the canopy and the airﬂow.Since the canopy was restricted by the retention line,the strong interaction between the canopy and the airﬂow certainly induced the retention line to move.When the canopy was placed at dif-ferent positions,theﬂuid–structure interaction between the canopy and the airﬂow was different,which might induce the retention line to move in a different way.Since our stereo-PIV setup could only measure aﬁxed vertical region, the movement of the retention line in that region might be different,which led to the different results at the location where y≈0.Figure10shows transverse proﬁles of ensemble-averaged normalized vorticity at different Reynolds numbers.For all cases,a vorticity protrusion was present near the region with y≈−1.0R,which was corresponded to the vorticity concentrated region in Fig.9.When the Reynolds number increases,the ensemble-averaged normalized vorticity dis-tributions change rgeﬂuctuations appear in the normalized vorticity in the area with y≈0,due to the retention line.This should be neglected.Moreover,for all these cases,at the region where y≈−1.4R,the ensemble-Measurement of theﬂow structures in the wakes of different types of parachute canopies233 Fig.11Normalized Reynolds stress distributions when Re=33,314.a Ribbon.b8-branches.c Cross(position A).d Cross(position B)averaged normalized vorticity values reduced approximately to0.It should be noted that theﬂuctuations appeared in the transverse proﬁles of the vorticity.This phenomenon might be explained by two factors.Firstly,when Johari and Desabrais[1]studied the vortex shedding in the near wake of a circular parachute canopy,their mean vorticity ﬁeld was obtained by averaging1000instantaneousﬁelds. However,their vorticity results also presented aﬂuctuated feature.Thus,we think that the highly turbulent and unsteady characteristics of the wake of the canopy might play an important role.Secondly,the geometric difference between the different canopies in the present study and the round canopy[1]might be a reason,which led to a more turbulent ﬂow.The normalized Reynolds stress distributions in the wakes of these three canopies at a Reynolds number of33,314are shown in Fig.11.As can be seen,the Reynolds stress levels of the ribbon canopy were much lower than those of the other canopies.As for the cross canopy,at position A,the majority of the Reynolds stress appeared within the area where−1.0R y 1.0R and decayed rapidly.At position B,the regions with concen-trated Reynolds stress were further extended to the locations where|y|>1.0R.Lower values of the Reynolds stress were found at position B,compared to position A.It should be noted that the Reynolds stress distribution of the8-branches canopy was similar to that of the cross canopy at position A.The transverse proﬁles of normalized Reynolds stress in the wakes of the parachute canopies are shown in Fig.12.As expected,the Reynolds stress levels of the ribbon canopy were much lower than those of the other canopies and234S.Pasqualini,etal. Fig.12The transverse proﬁles of normalized Reynolds stress where x=1.5R.a Ribbon.b8-branches.c Cross(position A).d Cross(position B)the maximum absolute Reynolds stress value was about 0.015.Even though the transverse proﬁles of Reynolds stress of the8-branches canopy was similar to those of the cross canopy at position A,the Reynolds stress val-ues were relatively smaller.As for the cross canopy,the absolute Reynolds stress values at position A were rela-tively higher than those at position B where−1.0R< y<−0.6R.Moreover,for all these cases,at the region where y≈−1.4R,the Reynolds stress values reduced to be approximately0.Figure13shows the normalized turbulent kinetic energy results at a Reynolds number of33,314.As can be seen,the turbulent kinetic energy levels of the ribbon canopy were much lower than those of the other canopies.In addition, since theﬂow through gap formed a larger turbulent wake than theﬂow over arm(Figs.5and7),such a phenomenon was also reﬂected in TKE distributions.The inﬂuence region of TKE at position B(Fig.13d)was found to be larger than that at position A(Fig.13c).Moreover,as for the8-branches canopy,TKE concentrated in the region where−1.1R< y<−0.5R.In our results,dark regions could also be found near the x-axis,which were caused by the retention line and should be neglected.The transverse proﬁles of normalized turbulent kinetic energy are shown in Fig.14.The results also demonstrated that the TKE values of the ribbon canopy were smaller than those of the other canopies.The maximum TKE value for the ribbon canopy was found to be about0.04,while for other two canopies,the maximum TKE value was about 0.09.As for the8-branches canopy,the dependence of TKE on Reynolds number was minor,and the largest discrepan-cies between the case when Re=74,362and the other three cases appeared in the region where−1.0R<y<−0.6R. As for the cross canopy,the TKE values at position B were relatively higher than those at position A where−1.2R< y<−0.9R.Moreover,for all these cases,at the region where y≈−1.4R,the TKE values decreased to be less than0.015.These results clearly show that the geometry of the parachute canopies has apparent effects on the wakeﬂow structures.Regarding this,when designing a parachute canopy,it is recommended to perform a comprehensiveMeasurement of theﬂow structures in the wakes of different types of parachute canopies235 Fig.13Normalized turbulent kinetic energy distributions when Re=33,314.a Ribbon.b8-branches.c Cross(position A).d Cross(position B)investigation on theﬂow structures in the wake of the canopy. This helps to obtain a better understanding of the rela-tionship between the change of the canopy shape and the ﬁnal aerodynamic performance of the parachute.In addi-tion,data obtained in this paper can be used for validations of theoretical models and simulations in computationalﬂuid dynamics.4ConclusionsFlow structures in the wakes of three types of parachute canopies were investigated using stereo-PIV.These parachute canopies were fabricated with the same surface area,and their geometries included ribbon canopy,8-branches canopy,and cross canopy.We measured and analyzed bothﬂow through the gap and over the arm of the cross parachute. The obtained results showed that the variation of the geometry of the parachute canopies had signiﬁcant inﬂu-ences on theﬂow structures in the turbulent wakes of these canopies.The increase of Reynolds number does not lead to a dramatic variation in the distributions of the x-component of the velocity,vorticity,Reynolds stress,and turbulent kinetic energy in the wakes of these parachute canopies.The recirculation zone in the wake of the rib-bon canopy formed at a further downstream region than that of the others.In addition,the normalized Reynolds stress and normalized turbulent kinetic energy of the rib-bon canopy were found to be less than those of the others.123236S.Pasqualini,etal. Fig.14The transverse proﬁles of normalized TKE where x=1.5.a Ribbon.b8-branches.c Cross(position A).d Cross(position B)Acknowledgements This work was supported by the Science and Technology Commission of Shanghai Municipality(Grant 15ZR1442700)and the Fundamental Research Funds for the Central Universities.References1.Johari,H.,Desabrais,K.J.:V ortex shedding in the near wake of aparachute canopy.J.Fluid Mech.536,185–207(2005)2.Cockrell,D.J.:The aerodynamics of parachutes,AGARD-AG-295(1987)3.Maydew,R.C.,Peterson, C.W.:Design and testing of high-performance parachutes,AGARDograph319(1991)4.Jorgensen,D.S.:Cruciform parachute aerodynamics.[Ph.D.the-sis],University of Leicester,UK(1982)5.Shen,C.Q.,Cockrell,D.J.:Aerodynamic characteristics andﬂowaround cross parachutes in steady motion.J.Aircr.25,317–323 (1988)6.Shen,C.Q.,Cockrell,D.J.:Flow Field Characteristics Around Cup-like Bluff Bodies,Parachute Canopies,AIAA-91-0855-CP.AIAA, San Diego,CA(1991)7.Peterson,C.W.,Strickland,J.H.,Higuchi,H.:Theﬂuid dynamicsof parachute inﬂation.Annu.Rev.Fluid Mech.28,361–387(1996) 8.Levin,D.,Shpund,Z.:Canopy geometry effect on the aerodynamicbehavior of cross-type parachutes.J.Aircr.34,648–652(1997) 9.Stein,K.,Tezduyar,T.,Kumar,V.,et al.:Aerodynamic interactionsbetween parachute canopies.J.Appl.Mech.70,50–57(2003)10.Ya˘g iz,O.E.,Albayrak,K.,Yildirim,R.O.:Experimental investiga-tion of three rotating parachutes.J.Aircr.43,1574–1577(2006) 11.Johari,H.,Levshin,A.:Interaction of a line vortex with a roundparachute canopy.J.Fluid.Struct.25,1258–1271(2009)12.Han,Y.H.,Wang,Y.W.,Yang,C.X.,et al.:Numerical methods foranalyzing the aerodynamic characteristics of cross parachute with permeability.In:AIAA Aerodynamic Decelerator Systems(ADS) Conference,Florida,AIAA2013-1283,Mar25–28(2013)13.Xue,X.,Koyama,H.,Nakamura,Y.,et al.:Effects of suspensionline onﬂowﬁeld around a supersonic parachute.Aerosp.Sci.Tech-nol.43,63–70(2015)14.Xue,X.,Nishiyama,Y.,Nakamura,Y.,et al.:Parametric study onaerodynamic interaction of supersonic parachute system.AIAA J.53,2796–2801(2015)15.Gao,X.,Zhang,Q.,Tang,Q.:Fluid-structure interaction analysisof parachuteﬁnite mass inﬂation.Int.J.Aerosp.Eng.28,1438727 (2016)16.Gao,X.,Zhang,Q.,Tang,Q.:Numerical modelling of Marssupersonic disk-gap-band parachute inﬂation.Adv.Space Res.57, 2259–2272(2016)17.Desabrais,K.J.:Velocityﬁeld measurements in the near wake of aparachute canopy.[Ph.D.thesis],Mechanical Engineering Depart-ment,Worcester Polytechnic Institute,Worcester,MA,USA(2002) 18.Wernet,M.P.,Locke,R.J.,Wroblewski,A.:Application of stereoPIV on a supersonic parachute model.In:47th AIAA Aerospace Sciences Meeting,AIAA2007-0070,Jan5–8(2007)19.Schairer,E.T.,Heineck,J.T.,Walker,L.A.,et al.:Simultaneous,unsteady PIV and photogrammetry measurements of a tension-cone decelerator in subsonicﬂow.In:15th International Sympo-123Measurement of theﬂow structures in the wakes of different types of parachute canopies237sium on Applications of Laser Techniques to Fluid Mechanics, Lisbon,Portugal,July5–8(2010)20.Sengupta,A.,Longmire,E.,Ryan,M.,et al.:Performance of aconical ribbon drogue parachute in the wake of a subscale Orion command module.In:Aerospace Conference,2012IEEE,Big Sky, MT,Mar3–10(2012)21.Jin,Z.,Pasqualini,S.,Qin,B.:Experimental investigation of theeffect of Reynolds number on theﬂow structures in the wake of a circular parachute canopy.Acta Mech.Sin.30,361–369(2014) 22.Jin,Z.,Pasqualini,S.,Yang,Z.:Experimental investigation of theﬂow structures in the wake of a cross parachute canopy.Euro.J.Mech.B Fluids60,70–81(2016)123。

改良经外周中心静脉置管留置长度的体表测量方法研究

2019年第23卷第24期实用临床医药杂志Journal of Clinical Medicine in Practice• 11 •改良经外周中心静脉置管留置长度的体表测量方法研究张玲芳，陶志芳，陆婷，王富芳，樊爱东(江苏省苏北人民医院肿瘤科，江苏扬州，225001)摘要：目的探讨改良的通过上肢静脉经外周中心静脉置管（PICC)置人导管长度测量的方法对提高导管尖端位于上腔静脉下段与卡沃-心房交接处（CAJ)以上位置的准确率的效果。

方法将接受PICC的160例患者随机分为对照组80例与改良组80例。

对照组测量方法为从上肢预穿刺点沿静脉走向到右胸锁关节外侧缘至第三肋间；改良组测量方法为从上肢预穿刺点沿静脉走向到右胸锁关节外侧缘至胸骨角末端终点（胸骨角向下2.00 cn)。

置管成功后，根据患者的X胸片确定导管尖端位置，比较2组测量方法使导管尖端位于上腔静脉下段与CAJ以上的准确率。

结果改良组PICC导管置人患者的上腔静脉下段与CAJ以上的位置准确率是95.00%，高于对照组68.75%，差异有统计学意义（P<0.05)。

结论改良组的测量方法能够使经上肢PICC的留置长度预测更加准确，有效提高导管尖端到指定位置的成功率。

关键词：上腔静脉下段；卡沃-心房交接处；胸椎上缘处；经外周中心静脉置管；留置长度；测量方法中图分类号：R730.5 文献标志码：A文章编号：1672-2353(2019)24-011-03 D0I: 10. 7619/jcmp.201924004Body surface measurement method forindwelling length of modified peripherallyinserted central catheterZ H A N G L i n g f a n g，T A O Zhifang,L U T i n g，W A N G F u f a n g,F A N A i d o n g(Department of Oncology，Subei People's Hospital，Yangzhou，Jiangsu，225001)A B S T R A C T：Objective T o explore the efficacy of measurement method for indwelling lengthof modified peripherally inserted central catheter(P I C C)through the vein of the upper extremi increasing accuracy of catheterization between the lower part of the superior vena cava atrial junction (C A J).M e t h o d s A total of160 patients with P I C C were randomly divided into control group and treatment group，with80 cases in each group.T h e measurement for the control group was from the p re-puncture point in upper limb along the vein d o w n to the third intercostal space b eside the right s ternal joint，the measurement for the treatment group was from the pre-puncture pointin upper limb along the vein d o w n to the sternal angle end point(2.00 c m beside the lateral edge of the righ tsternosacral joint.After successful the catheter tip was determined according to the patient’s X c h e s t radiograph.T h e accur measurement methods w as compared in the position of the tip of the catheter between the lower part of the superior vena cava and the C A J.Results T h e accuracy of placement of P I C C tube in the position between the lower part of the superior vena cava and the C A J was 95. 00%in the treatment group，which was significantly higher than 68. 75%in the control group (P <0. 05). Conclusion T h emeasurement method in the treatment group is more accurate to predict the length of PI( ripheral vein of u pper extremity and reduce the risk of complications.K E Y W O R D S：lower part of the superior vena cava;Cavo-atrial junction；upper racic vertebrae;peripherally inserted central catheter；indwelling length；measurement method经外周置入中心静脉导管（P I C C)通常经上渗性药物，且并发症较少[1]。

ARoomofOnesOwn英文介绍及赏析

ARoomofOnesOwn英⽂介绍及赏析A Room of One’s Own V I R G I N I A W O O L FContextVirginia Woolf was born Virginia Stephen in 1882 into a prominent and intellectually well-connected family. Her formal education was limited, but she grew up reading voraciously from the vast library of her father, the critic Leslie Stephen. Her youth was a traumatic one, including the early deaths of her mother and brother, a history of sexual abuse, and the beginnings of a depressive mental illness that plagued her intermittently throughout her life and eventually led to her suicide in 1941. After her father's death in 1904, Virginia and her sister (the painter Vanessa Bell) set up residence in a neighborhood of London called Bloomsbury, where they fell into association with a circle of intellectuals that included such figures as Lytton Strachey, Clive Bell, Roger Fry, and later E.M. Forster. In 1912, Virginia married Leonard Woolf, with whom she ran a small but influential printing press. The highly experimental character of her novels, and their brilliant formal innovations, established Woolf as a major figure of British modernism. Her novels, which include To the Lighthouse, Mrs. Dalloway, and The Waves, are particularly concerned with the lives and experiences of women.In October 1928, Virginia Woolf was invited to deliver lectures at Newnham College and Girton College, which at that time were the only women's colleges at Cambridge. These talks, on the topic of Women and Fiction, were expanded and revised into A Room of One's Own, which was printed in 1929. The title has become a virtual cliché in our culture, a fact that testifies to the book's importance and its enduring influence. Perhaps the single most important work of feminist literary criticism, A Room of One's Own explores the historical and contextual contingencies of literary achievement.SummaryThe dramatic setting of A Room of One's Own is that Woolf has been invited to lecture on the topic of Women and Fiction. She advances the thesis that "a woman must have money and a room of her own if she is to write fiction." Her essay is constructed as a partly-fictionalized narrative of the thinking that led her to adopt this thesis. She dramatizes that mental process in the character of an imaginary narrator ("call me Mary Beton, Mary Seton, Mary Carmichael or by any name you please—it is not a matter of any importance") who is in her same position, wrestling with the same topic.The narrator begins her investigation at Oxbridge College, where she reflects on the different educational experiences available to men and women as well as on more material differences in their lives. She then spends a day in the British Library perusing the scholarship on women, all of which has written by men and all of which has been written in anger. Turning to history, she finds so little data about the everyday lives of women that she decides to reconstruct their existence imaginatively. The figure of Judith Shakespeare is generated as an example of the tragic fate a highly intelligent woman would have met with under those circumstances. In light of this background, she considers the achievements of the major women novelists of the nineteenth century and reflects on the importance of tradition to an aspiring writer. A survey of the current state of literature follows, conducted through a reading the first novel of one of the narrator's contemporaries. Woolf closes the essay with an exhortation to her audience of women to take up the tradition that has been so hardly bequeathed to them, and to increase the endowment for their own daughters.Character List"I" - The fictionalized author-surrogate ("call me Mary Beton, Mary Seton, Mary Carmichael or by any name you please—it is not a matter of any importance") whose process of reflection on the topic "women and fiction" forms the substance of the essay.The Narrator (In-Depth Analysis)The Beadle - An Oxbridge security official who reminds the narrator that only "Fellows and Scholars" are permitted on the grass; women must remain on the gravel path.Mary Seton - Student at Fernham College and friend of the narrator.Mary Beton - The narrator's aunt, whose legacy of five hundred pounds a year secures her niece's financial independence. (Mary Beton is also one of the names Woolf assigns to her narrator, whose identity, she says, is irrelevant.)Judith Shakespeare - The imagined sister of William Shakespeare, who suffers greatly and eventually commits suicide because she can find no socially acceptable outlets for her genius.Mary Carmichael - A fictitious novelist, contemporary with the narrator of Woolf's essay. In her first novel, she has "broken the sentence, broken the sequence" and forever changed the course of women's writing.Mr. A - An imagined male author, whose work is overshadowed by a looming self-consciousness and petulant self-assertiveness.Analysis of Major CharacterThe NarratorThe unnamed female narrator is the only major character in A Room of One’s Own. She refers to herself only as “I”; in chapter one of the text, she tells the reader to call her “Mary Beton, Mary Seton, Mary Carmichael or any other name you please . . . ”The narrator assumes each of these names at various points throughout the text. The constantly shifting nature of her identity complicates her narrative even more, since we must consider carefully who she is at any given moment. However, her shifting identity also gives her a more universal voice: by taking on different names and identities, the narrator emphasizes that her words apply to all women, not just herself.The dramatic setting for A Room of One’s Own is Woolf’s thought process in preparation for giving a lecture on the topic “women and fiction.” But the fictionalized narrator is distinct from the author Woolf. The narrator lends a storylike quality to the text, and she often blends fact and fiction to prove her points. Her liberty with factuality suggests that no irrefutable truth exists in the world—all truth is relative and subjective.The narrator is an erudite and engaging storyteller, and she uses the book to explore the multifaceted and rather complicated history of literary achievement. Her provocative inquiries into the status quo of literature force readers to question the widely held assumption that women are inferior writers, compared to men, and this is why there is a dearth of memorable literary works by women. This literary journey is highlighted by numerous actual journeys, such as the journey around Oxbridge College and her tour of the British library. She interweaves her journeys with her own theories about the world—including the principle of “incandescence.” Woolf defines incandescence as the state in which everything is personal burns away and what is left is the “nugget of pure truth” in the art. This is the ideal state in which everything is consumed in the in tensity and truth of one’s art. The narrator skillfully leads the reader through one of the most important works of feminist literary history to d ate. Themes, Motifs & SymbolsThemesThe Importance of MoneyFor the narrator of A Room of One’s Own, money is the primary element that prevents women from having a room of their own, and thus, having money is of the utmost importance. Because women do not have power, their creativity has been systematically stifled throughout the ages. The narrator writes, “Int ellectual freedom depends upon material things. Poetry depends upon intellectual freedom. And women have always been poor, not for two hundred years merely, but from the beginning of time . . .” She uses this quotation to explain why so few women have writ ten successful poetry. She believes that the writing of novels lends itself more easily to frequent starts and stops, so women are more likely to write novels than poetry: women must contend with frequent interruptions because they are so often deprived of a room of their own in which to write. Without money, the narrator implies, women will remain in second place to their creative male counterparts. The financial discrepancy between men and women at the time of Woolf’s writing perpetuated the myth that wom en were less successful writers.The Subjectivity of TruthIn A Room of One’s Own, the narrator argues that even history is subjective. What she seeks is nothing less than “the essenti al oil of truth,” but this eludes her, and she eventually concludes that no such thing exists. The narrator later writes, “When a subject is highly controversial, one cannot hope to tell the truth. One can only show how one came to hold whatever opinion one does hold.” To demonstrate the idea that opinion is the only thing that a person can actually “prove,” she fictionalizes her lecture, claiming, “Fiction is likely to contain more truth than fact.” Reality is not objective: rather, it is contingent up on the circumstances of one’s world. This argument complicates her narrativ e: Woolf forces her reader to question the veracity of everything she has presented as truth so far, and yet she also tells them that the fictional parts of any story contain more essential truth than the factual parts. With this observation she recasts the accepted truths and opinions of countless literary works.MotifsInterruptionsWhen the narrator is interrupted in A Room of One’s Own, she generally fails to regain her original concentration, suggesting that women without private spaces of their own, free of interruptions, are doomed to difficulty and even failure in their work. While the narrator is describing Oxbridge University in chapter one, her attention is drawn to a cat without a tail. The narrator finds this cat to be out of place, and she uses the sight of this cat to take her text in a different direction. The oddly jarring andincongruous sight of a cat without a tail—which causes the narrator to completely lose her train of thought—is an exercise in allowing the reader to experience what it might feel like to be a woman writer. Although the narrator goes on to make an interesting and valuable point about the atmosphere at her luncheon, she has lost her original point. This shift underscores her claim that women, who so often lack a room of their own and the time to write, cannot compete against the men who are not forced to struggle for such basic necessities.Gender InequalityThroughout A Room of One’s Own, the narrator emphasizes the fact that women are treated unequally in her society and that this is why they have produced less impressive works of writing than men. To illustrate her point, the narrator creates a woman named Judith Shakespeare, the imaginary twin sister of William Shakespeare. The narrator uses Judith to show how society systematically discriminates against women. Judith is just as talented as her brother William, but while his talents are recognized and encouraged by their family and the rest of their society, Judith’s are underestimated and explicitly deemphasi zed. Judith writes, but she is secretive and ashamed of it. She is engaged at a fairly young age; when she begs not to have to marry, her beloved father beats her. She eventually commits suicide. The narrator invents the tragic figure of Judith to prove that a woman as talented as Shakespeare could never have achieved such success. Talent is an essential component of Shakespeare’s success, but because women are treated so differently, a female Shakespeare would have fared quite differently even if she’d had as much talent as Shakespeare did.SymbolsA Room of One’s OwnThe central point of A Room of One’s Own is that every woman needs a room of her own—something men are able to enjoy without question. A room of her own would provide a woman with the time and the space to engage in uninterrupted writing time. During Woolf’s time, women rarely enjoyed these luxuries. They remained elusive to women, and, as a result, their art suffered. But Woolf is concerned with more than just the room itself. She uses the room as a symbol for many larger issues, such as privacy, leisure time, and financial independence, each of which is an essential component of the countless inequalities between men and women. Woolf predicts that until these inequalities are rectified, women will remain second-class citizens and their literary achievements will also be branded as such.。

Supersymmetric QCD Parity Nonconservation in Top Quark Pairs at the Tevatron

a r X i v :h e p -p h /9709275v 2 12 F eb 1998PKU-TP-97-20MSUHEP-70825THU-TP-97-08hep-ph/9709275Supersymmetric QCD Parity Nonconservation inTop Quark Pairs at the TevatronChong Sheng Li (a ),C.–P.Yuan (b ),Hong-Yi Zhou (c )(a )Department of Physics,Peking University,Beijing 100871,China (b )Department of Physics and Astronomy,Michigan State University,East Lansing,Michigan 48824,USA(c )Institute of Modern Physics and Department of Physics,Tsinghua University,Beijing 100084,ChinaABSTRACTIn the supersymmetry (SUSY)models,because of the mass diﬀerence between the left-and right-top squarks,the supersymmetric QCD in-teractions can generate parity violating eﬀects in the production of t ¯t pairs.We show that SUSY QCD radiative corrections to the parity vi-olating asymmetry in the production rates of the left-and right-handedtop quarks via the q ¯q →t ¯tprocess can reach about 3%at the Fermilab Tevatron with√1IntroductionIn a recent paper[1],we studied the parity violating asymmetry induced from the supersymmetric electroweak(SUSY EW)and Yukawa(SUSY Yukawa)corrections at the one loop level.Two classes of supersymmetry(SUSY)models were considered:the mini-mal supergravity(mSUGRA)models[2]and the minimal supersymmetric models(MSSM) with scenarios motivated by current data[3,4].After sampling a range of values of SUSY parameters in the region that might give large contributions to the parity-violating asym-metry A,and which are also consistent with either of the above two classes of models, we found that the asymmetry A due to the one-loop SUSY EW(αm2t/m2W)and SUSY Yukawa corrections for the production process q¯q→g→t¯t at the upgraded Tevatron is generally small,less than a few percent.However,the sign can be either positive or negative depending on the values of the SUSY parameters.(The eﬀect from the Standard Model(SM)weak corrections to this asymmetry is typically less than a fraction of percent [5,6].)In the supersymmetric Standard Model,some superparticles experience not only the electroweak interaction but also the strong interaction.Although the SM QCD interaction respects the discrete symmetries of charge conjugation(C)and parity(P),the SUSY QCD interactions for superparticles,in their mass eigenstates,need not be C and P invariant. (Needless to say,in the strong interaction eigenstates,the SUSY QCD interaction is C-and P-invariant.)For either the mSUGRA or the MSSM models,the masses of the left-stop(the supersymmetric partner of the left-handed top quark)and the right-stop can be noticeably diﬀerent due to the large mass of the top quark.This is a general feature of the supersymmetry models in which the electroweak symmetry is broken spontaneously via radiative corrections.Since both the left-stop and the right-stop contribute to the loop corrections for the t¯t pair production process q¯q,gg→t¯t,the diﬀerent masses of the top-squarks will induce a parity violating asymmetry.It is this eﬀect that we shall study in this paper.Because the t¯t pairs are produced predominantly via the QCD process q¯q→t¯t√at the Tevatron(a p¯p collider with CM energyThis amounts to a signal at∼90%c.l.(conﬁdence level)with2fb−1,or99%c.l.with10 fb−1.Thus,a study of A at the Tevatron could yield information about the allowed range of SUSY model parameter space.2SUSY QCD Corrections and Parity ViolationI.Squark mixingsIn the MSSM the mass eigenstates˜q1and˜q2of the squarks are related to the(strong) current eigenstates˜q L and˜q R via the mixing angleθ˜q by˜q1=˜q L cosθ˜q+˜q R sinθ˜q,˜q2=−˜q L sinθ˜q+˜q R cosθ˜q.(1) For the top squarks,the mixing angleθ˜t and the masses m˜t1,2can be calculated by diago-nalizing the following mass matrix[3],M2˜t = M2˜t L m t m LRm t m LR M2˜t R,M2˜t L =m2˜t L+m2t+(13sin2θW)cos(2β)m2Z,M2˜t R =m2˜t R+m2t+2N R+N L=σR−σLSome of the one loop scattering amplitudes of q ¯q →t ¯twere already presented in Refs.[10,11]for calculating the total production rates of t ¯tpairs.To calculate the parity violating asymmetry A in the t ¯tsystem,additional renormalized amplitudes are needed.In terms of the tree-level amplitude,M 0,and the next-to-leading order SUSY QCD corrections,δM ,the renormalized amplitudes at the one-loop level can be writtenas M =M 0+δM .Denote the momenta of the initial and the ﬁnal state particles asq l (p 4)¯q m (p 3)→t i (p 2)¯tj (p 1),and the Dirac four-spinor as u i ≡u (p i )(v i ≡v (p i ))for particle (anti-particle)i .Then,M 0=ig 2s (T c ji T clm )J 1·J 2/ˆs ,where J µ1=¯v (p 3)γµu (p 4)and J µ2=¯u (p 2)γµv (p 1);ˆs is the invariant mass of the t ¯t pair;g s and T c ij are the gauge coupling andthe generator of the group SU (3)c ,respectively.To calculate the parity violating asymmetry induced by the SUSY QCD eﬀects,we fol-low the method presented in Ref.[12],in which the asymmetry was calculated numerically using the helicity amplitude method.To obtain the renormalized scattering amplitudes,we adopt the dimensional regularization scheme to regulate the ultraviolet divergences and the on-mass-shell renormalization scheme [13]to deﬁne the input parameters.The SUSY QCD corrections to the scattering amplitudes arise from the vertex diagram,the gluon self-energy and the box diagrams,as well as the crossed-box diagrams.The renormalized amplitudes can be written asδM =δM v 1+δM v 2+δM s +δM DB +δM CB ,(4)where δM v 1and δM v 2are vertex corrections,δM s is the self-energy correction,and δM DB and δM CB are the contributions from the box diagrams and crossed-box diagrams,respec-tively.The results for these separate contributions are,δM v 1=ig 2s(T c ji T c lm )¯u (p 2)[F v 10·J 1+F v 11/J 1+/J 1/F v 13+/F v 14/J 1+/F v 16·J 1+(F Av 11/J 1+/J 1/F Av 13+/F Av 14/J 1+/F Av 16·J 1)γ5]v (p 1)/ˆs ,(5)δM v 2=ig 2s (T c ji T c lm )¯v (p 3)(F v 21/J 2+/F v 26·J 2)u (p 4)/ˆs ,(6)δM s =F s0M 0,(7)δM DB =ig 2s7δM CB=ig2s1ˆs=M t¯t.1As discussed in the previous section,the SUSY parameters relevant to our study arem˜t1,m˜t2,θ˜t(or m˜tL,m˜tR,m LR),m˜b R,m˜qL,R,and m˜g.To simplify our discussion,we assumem˜qL,R =m˜b R=m˜tL,so that there are only four SUSY parameters to be considered,m˜t1,m˜t2,θ˜t and m˜g.(The SU(2)L gauge symmetry requires that m2˜b L=m2˜t L.)The mSUGRA models predict radiative breaking of the electroweak gauge symmetryinduced by the large top quark mass.Consequently,it is possible to have large splitting in the masses of the left-stop and the right-stop,while the masses of all the other(left-or right-)squarks are about the same[17].For the MSSM models with scenarios motivated by current data[4],a light˜t1is likely to be the right-stop(˜t R),with a mass at the order of m W;the other squarks are heavier than˜t1.Since heavy superparticles decouple in loopcontributions,we expect that a lighter˜t1would induce a larger asymmetry.Because theparity-violating eﬀects from the SUSY QCD interactions arise from the mass diﬀerencebetween˜t1and˜t2,it is obvious from Eq.(1)that the largest parity violating eﬀect occurswhenθ˜t is±π/2for m˜tR≤m˜t L.Whenθ˜t=±π/4,the parity asymmetry should be zero. This is evident from the results shown in the Appendix,which indicate that the amplitudesthat contribute to A are all proportional to Z i=∓cos(2θ˜t).In either the mSUGRA or the MSSM models,the gluinos are usually as heavy as thelight squarks,on the order of a few hundred GeV.However,Farrar has argued[18]that lightgluinos are still a possibility.If gluinos are light,then a heavy top quark can decay into astop and a light gluino for m˜t1<(m t−m˜g)such that the branching ratio of t→bW+could show a large diﬀerence from that(∼100%)predicted by the SM.The CDF collaborationhas measured the branching ratio of t→bW+to be0.87+0.13−0.30+0.13−0.11[19].At the1σlevel,this implies that a50(90)GeV˜t1requires the mass of the gluino to be larger than about 120(80)GeV forθ˜t=±π/2.However,at the2σlevel(i.e.95%c.l.),there is no useful limit on the mass of the gluino.2To represent diﬀerent classes of SUSY models in which the parity-violating asymmetry induced by the SUSY QCD interactions can be large,we show in Table1four represen-tative sets of models.They are labeled by the set of parameters(m˜t1,m˜t2,θ˜t),which areequal to(50,1033,−1.38),(90,1033,−1.38),(50,558,−1.25)and(90,558,−1.25),respec-tively.(All the masses are in units of GeV.)Based upon Eq.(2),one can also label thesemodels by(m˜tL ,m˜tR,m LR),which are(1000,90,1100),(1000,118,1100),(500,40,520)and(500,88,520),respectively,forβ=π/4.It is interesting to note that for all the models listed in Table1,the asymmetry A is negative(i.e.σR<σL)for m˜g<200GeV,and its magnitude can be as large as 3%for models with light˜t1.The maximal|A|occurs when m˜g is about equal to(m t−m˜t1)because of the mass threshold enhancement.For m˜g>200GeV,the asymmetry A becomes positive,with a few percent in magnitude,and monotonically decreases as m˜g paring these results with those induced by the SUSY EW and SUSY Yukawa corrections[1],it is clear that SUSY QCD interactions can generate a relatively larger parity-violating asymmetry.The diﬀerential asymmetry A(M t¯t)also exhibits an interesting behaviour as a function of the t¯t invariant mass M t¯t.This is illustrated in Table2for theﬁrst SUSY model inTable1((m˜t1,m˜t2,θ˜t)=(50,1033,-1.38)).As shown,|A(M t¯t)|increases as M t¯t increasesfor m˜g<200GeV,which is similar to the eﬀects from the SUSY EW and SUSY YukawaTable1:Parity violating asymmetry A in p¯p→t¯t+X,as a function of m˜g,for four sets of SUSYmodels labeled by(m˜t1,m˜t2,θ˜t).m˜g(GeV)(90,1033,−1.38)(90,558,−1.25)-1.10%-0.98%-1.53%-1.40%-2.34%-2.21%-2.86%-2.89%-3.16%-3.43%-2.58%-2.80%-1.18%-1.30%0.99%0.82%1.60% 1.40%1.53% 1.35%1.27% 1.16%1.04%0.95%3Without the cuts in(10),the values of A for theﬁrst model in Table1are−1.0%,−2.65%,and +0.94%for m˜g=2,120,200GeV,respectively.4These apparent problems in Ref.[22]were also pointed out in Ref.[21].6Table2:The diﬀerential asymmetry A(M t¯t)and cross section dσ/d M t¯t(in unit of fb/GeV)as a function of M t¯t for theﬁrst SUSY model in Table1with various m˜g values.M t¯t(GeV)m˜g=120GeV358-0.73%16.3-0.42%36.60.95%31.4 378-1.63%29.0-0.67%38.7 2.12%34.2 398-2.17%27.2-0.82%35.0 3.67%32.4 425-2.64%22.8-1.13%24.1 1.05%20.0 475-3.40%13.8-1.47%13.7-0.62%10.8 525-3.81%7.9-1.76%7.7-1.71% 5.9 575-4.34% 4.4-3.26%0.032-4.66%0.024Table3:The SUSY QCD corrections(∆σ)to the q¯q→t¯t production rates at the Tevatron with √2501001201351501752002252502753001.170.26-0.04-0.18-0.87-0.49-0.020.330.300.240.190.16m˜g=200GeV and m˜t=m˜q=75GeV,we obtain a39%,in contrast to33%,correction in the total cross section without cuts.Including cuts in(10)only slightly increases the correction to40%.For completeness,in Table3we show the SUSY QCD corrections∆σto the q¯q→t¯t√production rates at the Tevatron withUp to now,we have only considered the one loop SUSY QCD eﬀects on the parity violating asymmetry A in t¯t pair production.Amusingly,the parity-violating asymmetry induced by the SUSY QCD interactions can also occur at the Born level.If gluinos are very light,of the order of1GeV,this asymmetry can be generated by the tree level process ˜g˜g→t¯t.Unfortunately,its production rate is smaller than the gg→t¯t rate,which is only about one tenth of the q¯q→t¯t rate at the Tevatron.Hence,it cannot be measured at the Tevatron.However,at the CERN Large Hadron Collider(LHC),the production rate of˜g˜g→t¯t is large enough to allow the measurement of the parity-violating asymmetry induced by the SUSY QCD interactions.The asymmetry in the production rates of t L¯t and t R¯t,generated by the˜g˜g fusion process alone,can reach about10%for M t¯t larger than about500GeV.We shall present its details and include the eﬀect from the gg and q¯q fusion processes in a future publication[23].This work is supported in part by the National Natural Science Foundation of China, and by the U.S.NSF grant PHY-9507683.AppendixWe give here the form factors for the matrix elements appearing in Eqs.(8)-(12). They are written in terms of the conventional one-,two-,three-and four-point scalar loop integrals deﬁned in Ref.[24].F v1µ= i=1,23αs12π[m˜g Y i((p2−p1)µC0/2−Cµ](−p2,k,m˜g,m˜t i,m˜t i)F v11= i=1,23αs3π[B1X i−2m t m˜g B′0Y i+2m2t B′1X i](m2t,m˜g,m˜t i)F v1µ3= i=1,23αs8π(−2X i)Cµν(−p2,k,m˜ti,m˜g,m˜g)8+ i=1,2αs8πZ i(C20+(m2t−m2˜g)C0)(−p2,k,m˜t i,m˜g,m˜g) + i=1,2αs8πZ i m t Cµ(−p2,k,m˜ti,m˜g,m˜g)F Av1µ4=−F Av1µ3F Av1µν6= i=1,23αs12πZ i[((p2−p1)νCµ/2−Cµν)](−p2,k,m˜g,m˜t i,m˜t i)F v21=3αs3πB1(m2q,m˜g,m˜q)F v2µν6=3αs6π[−(p2−p1)νCµ/2−Cµν](p4,−k,m˜g,m˜q,m˜q)F s0=3αs6−(m2˜g(B0+1)−2B22)/k2)(k2,m˜g,m˜g)−(B21+B1+14π (2B22(k2,m˜q,m˜q)−A0(m˜q))/k2−2B′22(0,m˜q,m˜q)F DB 1= i=1,2αs4π(m t X i+m˜g Y i)Dµ(−p2,p4,p3,m˜ti,m˜g,m˜q,m˜g)F DBµν3= i=1,2αs4πZ i(m2t−m2˜g)D0(−p2,p4,p3,m˜t i,m˜g,m˜q,m˜g)F DBµ5= i=1,2αsF DBµν6= i=1,2αs√√√√∂p2,B′1=∂B1(p2,m1,m2)∂p2,C20=gµνCµν−1References[1]C.S.Li,R.J.Oakes,J.M.Yang,and C.-P.Yuan,Phys.Lett.B398(1997)298.[2]For reviews,see H.P.Nilles,Phys.Rep.110(1984)1;P.Nath,R.Arnowitt and A.Chamseddine,Applied N=1Supergravity,ICTP series in Theoretical Physics,(World Scientiﬁc,1984);L.E.Ib´a˜n ez and G.G.Ross,in Perspectives on Higgs Physics,ed.G.L.Kane,(World Scientiﬁc,1993).[3]H.E.Haber and C.L.Kane,Phys.Rep.117(1985)75;J.F.Gunion and H.E.Haber,Nucl.Phys.B272(1986)1.[4]S.Ambrosanio,G.L.Kane,G.D.Kribs,S.P.Martin and S.Mrenna,Phys.Rev.Lett.76(1996)3498;S.Dimopoulos,M.Dine,S.Raby and S.Thomas,Phys.Rev.Lett.76(1996)3494.[5]Kao,dinsky and C.–P.Yuan,FSU-HEP-930508,1993(unpublished);DPFConf.1994:pp.713-716;Int.J Mod.Phys.A12(1997)1341.[6]C.Kao,Phys.Lett.B348(1995)155.[7]enen,J.Smith and W.L.van Neerven,Phys.Lett.B321(1994)254.[8]W.Beenakker,A.Denner,W.Hollik,R.Mertig,T.Sack and D.Wackeroth,Nucl.Phys.B411(1994)343.[9]D.Amidei and R.Brock,“Report of the T eV2000Study Group on Future ElectroWeakPhysics at the Tevatron”,Fermilab-Pub-96/082,and references therein.[10]J.M.Yang and C.S.Li,Phys.Rev.D52(1995)1541;C.S.Li,B.Q.Hu,J.M.Yang,and C.G.Hu,Phys.Rev.D52(1995)5014;Erratum,Phys.Rev.D53(1996)4112;C.S.Li,H.Y.Zhou,Y.L.Zhu,and J.M.Yang,Phys.Lett.B379(1996)135;J.M.Yang and C.S.Li,Phys.Rev.D54(1996)4380.[11]J.Kim,J.L.Lopez,D.V.Nanopoulos,and R.Rangarajan,Phys.Rev.D54(1996)4364;S.Catani et al.,Phys.Lett.B378(1996)329;T.Gehrmann et al.,Phys.Lett.B381(1996)221;J.A.Coarasa et al.,hep-ph/9607485;S.Frixione,hep-ph/9702287,to be published in Heavy Flavours II,World Scientiﬁc, Singapore.[12]G.L.Kane,dinsky and C.–P.Yuan,Phys.Rev.D45(1992)124.[13]A.Denner,Fortschr.Phys.,41,307(1993).[14]CDF Collaboration,Phys.Rev.Lett.74(1995)2626;DØCollaboration,Phys.Rev.Lett.74(1995)2632;L.Roberts,in the Proceedings of the28th International Conference on High Energy Physics,Warsaw,Poland,1996.[15]A.D.Martin,W.J.Stirling and R.G.Roberts,Phys.Lett.B354(1995)155.[16]i,J.Huston,S.Kuhlmann,F.Olness,J.Owens,D.Soper,W.K.Tung,H.Weerts,Phys.Rev.D55(1997)1280.[17]For example,see G.L.Kane,C.Kolda,L.Roszkowski,J.D.Wells Phys.Rev.D49(1994)6173;and references therein.[18]G.R.Farrar,hep-ph/9707467;and references therein.[19]By CDF Collaboration(J.Incandela for the collaboration),Nuovo Cim.109A(1996)741.[20]L.Clavelli and G.R.Goldstein,hep-ph/9708405.[21]Z.Sullivan,Phys.Rev.D56,451(1997).[22]S.Alam,K.Hagiwara,and S.Matsumoto,Phys.Rev.D55(1997)1307.[23]C.S.Li,P.Nadolsky,C.–P.Yuan and H.Y.Zhou,in preparation.[24]G.Passarino and M.Veltman,Nucl.Phys.B160(1979)151;G.´t Hooft and M.Veltman,Nucl.Phys.B153(1979)365.。

Test of $CPT$ Symmetry in $CP$-violating $B$ Decays

0 ¯0 > , p1 |Bd > +q1 |B d 0 ¯0 > , p2 |Bd > −q2 |B d
(1)
0 ¯0 where p1,2 and q1,2 are parameters of the Bd Bd mass matrix elements. For convenience, the
Γ 0 0 ¯0 > , > +˜ g+ (t)|B |Bd (t) > = e−(im+ 2 )t g+ (t)|Bd d
t 0 ¯0 > , ¯ 0 (t) > = e−(im+ Γ 2) g ˜− (t)|Bd > +g− (t)|B |B d d
Hale Waihona Puke (3)where∆Γ t ∆Γ t θ θ g± (t) = cos2 e±(i∆m− 2 ) 2 + sin2 e∓(i∆m− 2 ) 2 , 2 2 t ∆Γ t ∆Γ θ θ g ˜± (t) = sin cos e(i∆m− 2 ) 2 − e−(i∆m− 2 ) 2 e±iφ . 2 2
d d
In this work, we shall make an instructive analysis of the eﬀects of CP T violation on CP violating asymmetries in neutral B -meson decays. Both time-dependent and time-integrated CP asymmetries are calculated to meet various possible measurements at e+ e− B factories. We suggest several ways for distinguishing CP T violation from direct CP violation in B decay amplitudes and indirect CP violation via interference between decay and mixing. We show that it is diﬃcult to extract the CP T -violating information from the time-integrated ¯ 0 → ψKS and π + π − . measurements of neutral B decays to CP eigenstates such as B 0 /B

Measurement of the radiation field surrounding the Collider Detector at Fermilab

FERMILAB-Conf-04/010-EIEEE/NSS-MIC2003ConferencePortland,Oregon,October19-25,2003 Measurement of the radiationﬁeld surrounding the Collider Detector at FermilabKostas Kordas,Saverio D’Auria,Andy Hocker,Susan McGimpsey,Ludovic Nicolas,Richard J.Tesarek,and Steven Worm(CDF radiation monitoring group)Abstract—We present here theﬁrst direct and detailed mea-surements of the spatial distribution of the ionizing radiationsurrounding a hadron collider ing data from twodifferent exposures we measure the effect of additional shieldingon the radiationﬁeld around the Collider Detector at Fermilab(CDF).Employing a simple model we parameterize the ionizingradiationﬁeld surrounding the detector.Index Terms—Radiation measurement,ionizing radiation,ra-diationﬁeld,radiation damage.I.I NTRODUCTIONI N modern collider experiments,the supporting infrastructurelies external to the detector,but inside the radiation environ-ment surrounding the detector.The apparatus and its infrastruc-ture may be sensitive to both chronic and acute radiation doses.These doses induce additional detector occupancy,single-eventeffects in the supporting electronics,or even irreversible fail-ure.This sensitivity can lead to additional contamination ofphysics signals,corruption of the data,reduced reliability ofthe detector,or reduced detector lifetime[1].Knowledge ofthe spatial distribution,dose rate and sources of radiation are,therefore,critical components in the design and operation of anexperiment at a hadron collider.Most experiment designs haverelied on a combination of radiation damage measurements andcomputer simulations of the radiation environment[2],[3],[4].However,no substantial measurements of the radiationﬁeldsurrounding a collider detector exist in the literature.In this article,we present theﬁrst detailed measurement ofthe radiationﬁeld surrounding the Collider Detector at FermilabEE EE 0123Fig.2.The principle of thermal luminescence.Photon radiation brings the material in a meta-stable state,,with a long lifetime (left).Heating the material leads to emission of visible photons (right).with an energy of TeV .Protons travel along thedirection and collide with oncoming antiprotons at the center of the CDF detector at (see Fig.1).In the CDF cylindrical geometry we denote the distance from the beam line by ,and the azimuthal angle around the -axis by .A series of semiconductor and gaseous detectors,immersed in a T solenoidal magnetic ﬁeld within m of the beam line,measure charged particles produced at collisions.Out-side the tracking volume,calorimeters measure the total energy of neutral and charged particles from the proton-antiproton collisions.The calorimeters are surrounded by muon detectors.The number of collisions at the center of CDF is recorded by the Cherenkov Luminosity Counter (CLC)[5].On either side of the detector,scintillator counters surrounding the beam pipe record losses from protons and antiprotons ejected from the beam.Proton (antiproton)losses are deﬁned as the coin-cidence of a counter signal with a proton (antiproton)bunch crossing the plane of the scintillator on its way into the CDF detector.B.Thermal Luminescent DosimetersTwo types of Harshaw TLD chips are used for the radiation measurements.One type (TLD-700)is based on LiF and is sensitive to ionizing radiation.Ionizing radiation passing through the dosimeter brings the material in a meta-stable state with very long lifetime.Heating the TLD chip leads to a transition back to ground state accompanied by the emission of a photon (see Fig.2).The number of photons produced is proportional to the population in these meta-stable states,which is in turn proportional to the amount of ionizing radiation that has traversed the TLD chip.The other dosimeter type (TLD-600)is based on LiF and is sensitive to both ionizing radiation and low-energy neutrons (keV).The reaction Li H results in a transition to the meta-stable state discussed above,by means of the recoiling tritium (H)and helium ()nuclei.Dosimeters are grouped in two triplets,one of each TLD type,and put in cm cm holders made of mm thick FR-4(see Fig.3).The TLD’s are held in place bym thick kapton tape,and are subsequently placed in 160locations around the collision hall to accumulate radiation,on both the proton ()and the antiproton ()sidesFig.3.A mm thick FR-4TLD holder.TLD-700(round)and TLD-600(square)dosimeters are kept in place bym thick kapton tape.(see Fig.1):i)around the entrance points of the beams to the collision hall,at locations on each side,at cm,cm,,ii)on the horizontal and verticalbars supporting the Tevatron quadrupoles,at locations on each side,at cm,cm,,iii)on the face of the steel wheels hosting the forward muondetectors,atlocations on each side,at cm,cm,,iv)on the collision hallwalls running parallel to the beam line,at locations,atcm,cm,,v)on the racks hosting readout electronics for thesilicon tracking detectors,at locations,at cm,cm,,and vi)on the racks hostingpower supplies for the drift chamber tracker,at locations,at cm,cm,.C.Calibration and DosimetryWe calibrate the TLD response to ionizing radiation with a rad photon exposure from a Cs source [6].A calibration factor (in rad/nC)for each TLD chip is then determined by heating up the chip and measuring the light yield using a Harshaw model 2000TLD reader [7].A reproducibility of 1and a chip-to-chip variation of 3is observed.The response of the TLD-600chips to neutrons is calibrated with a rad exposure to a Cf source.We obtain a 10reproducability and a 15chip-to-chip variation.LiF TLD’s are known to exhibit non-linearity for doses above rad.In order to account for this behavior,we expose a small sample of TLD’s to doses up to krad and we measure a correction factor,deﬁned as the ratio of the received dose over the dose estimated from the linear-response assumption (see Fig.4).The dosimeters exposed around the CDF collision hall have measured doses in the range of 0.1rad to 1.2krad.We extract the ionizing radiation,(rad),each TLD-700chip has received due to its exposure in the collision hall,by using the expression:(1)where is the reading (nC)from this TLD chip,is thecalibration factor (rad/nC)for its response to ionizing radiation,1101010101010110101010Dose (rad)R e s p o n c e (n C )0.30.40.50.60.70.80.911.1110101010Predicted Dose (rad)C o r r e c t i o n F a c t o rFig.4.a)Response of TLD-700dosimeters to ionizing radiation as a function of received dose;note the super-linear behavior for doses above rad.b)The non-linearity correction factor as a function of the dose estimated from the linear-response assumption.TABLE IB EAM CONDITIONS AT CDF FOR THETHREETLD EXPOSURE PERIODS .Beam ()Period1)May -Jun.20028.16 1.4131.71.9256.43)Jan.-May 200361.57.5is the non-linearity correction factor,and is the background ionizing radiation dose measured by a number of control TLD-700chips which were not placed in the collision hall.Averaging the doses measured by the three TLD chips ina given holder,we obtain the ionizing radiation dose,,at the location of the TLD holder in study.D.Radiation measurements and effectiveness of shielding TLD measurements are taken during three different periods of the Tevatron operations.Table I shows the integrated beam conditions during the three exposure periods:the number of protons and antiprotons in the Tevatron,the number of lost beam particles recorded,and the number of collisions in terms of time-integrated luminosity,(corresponds to about interactions).The ﬁrst exposure period was a test period;only a partial set of TLDs was installed around the collision hall.We,therefore,focus our discussion to period 2(June to October 2002)and period 3(January to May 2003).During a break in the Tevatron operations in January 2003(just before period 3commenced),shielding was installed around the focusing quadrupoles on the proton side (see Fig.5).No shielding was installed on the antiproton side because the beam losses are much smaller (see Table I).In Figure 6we show the ratio of the dose rate,(dose per of collisions),in period 3over that of period 2at various locations.Each point on the plot is the weighted average of the ratios of the measurements in and for the given location.On the antiproton side,where no shielding was installed,the dose rates in period 3are not consistently highershieldingpmovable for tracker accesscollision pointFig.5.Elevation view of a quadrant of CDF,with the shielding installed around the focusing quadrupoles on the proton side,just before data-taking resumed at the end of January 2003(beginning of exposure period 3).Z (cm)R d o s e 3 / R d o s e 20.40.50.60.70.80.911.11.21.31.4Fig.6.Ratio (period 3over period 2)of ionizing radiation dose rates,(dose per of collisions),at various locations.or lower compared to period 2;the dose rates range from 20higher (at cm),to 22lower (at cm).On the proton side,where shielding was installed,the dose rates in period 3are systematically lower than in period 2;from 6(at cm)to 48(at cm),for an average reduction of 25.Assuming that the radiation at a given point is the linear super-position of contributions from beam losses and collisions,we can write the dose rate,,asZ (cm)R d o s e p / R d o s e p -0.60.811.21.41.61.82Fig.7.Ratio of dose rates on the proton side over the antiproton side,at variouslocations in exposure periods 2(circles)and 3(stars).If we assume that the collision contribution to the dose ()scales with the number of collisions,we expect thatis the same in periods 2and 3at the points where we perform our measurements.The fact that the dose rates are different in period 3than in period 2means that the rate of the loss contributions ()is different in the two periods (see Eqn.2).Therefore,we conclude that the 25reduction in dose rates on the proton side,quoted in the previous paragraph,is solely due to a reduction in the beam loss rates.Figure 7shows the ratio of the dose rates on the proton and antiproton sides,at several locations in periods 2(circles)and 3(stars).In both exposure periods,the dose rates on the proton side are usually higher than those on the antiproton side.In period 2asymmetries as high as are observed,whereas in period 3,when the shielding on the proton side was installed,this asymmetry is no more than .Given the symmetry of the CDF detector,we can assume that the dose contribution due to collisions does not exhibit a preference for positive values over negative values.Thus,we expect the dose rate asymmetry between the proton and antiproton sides to arise from an asymmetry in the rate of loss contributions (see Eqn.2).III.M ODELINGTHE RADIATION FIELDThe ionizing radiation measurements are parameterized using a model based on previous CDF measurements of the silicon radiation damage proﬁle [8]and direct radiation measurements in the CDF tracking volume [9].This model assumes cylindrical symmetry of the radiation around the beam line,with a radialdependence which follows a power law in,where is the distance from the beam line.For any point on a plane perpendicular to the beam axis at ,we write for the dose rateRadius (cm)D o s e /L u m i n o s i t y (r a d /p b -1)0.030.040.050.060.070.080.090.10.20.30.4200300400500600Fig.8.Dose rate (dose per of collisions)as a function of the distance from the beam line,for measurements at cm in exposure period 2.The data are ﬁtted to the radiation ﬁled model in Equation 3.(dose perof collisions),:(3)where is the absolute normalization,is the power lawexponent,andZ (cm)A (r a d /p b -1)Z (cm)10100.60.811.21.41.61.82Fig.9.Fit parameters of the radiation ﬁeld model in Equation 3(),for measurements in period 2;normalization (left)and power law exponent (right)as a function of .Z (cm)A (r a d /p b -1)Z (cm)10100.60.811.21.41.61.82Fig.10.Fit parameters of the radiation ﬁeld model in Equation 3(),for measurements in period 3;normalization (left)and power law exponent (right)as a function of .is used,ﬁts to the data yield exponents with a strong -dependence;in the collision hall hosting the CDF detector.We believe that our data can serve as a calibration point for simulations of the radiation environment in future hadron colliders.A CKNOWLEDGMENTThe authors would like to thank the people at Fermilab’s Radiation Physics Calibration Facility,the Silicon Detector Lab and CDF for their help in calibrating the TLD’s,placing them to the holders and installing them in CDF.Special thanks to Minjeong Kim and Fabio Happacher for the invaluable help in placing/harvesting the dosimeters,and to the radiation monitoring group at Argonne labs for letting us use their TLD reader when needed.R EFERENCES[1]R.J.Tesarek et al.,“Radiation effects in CDF switching power supplies”,CDF internal note 5903,May 2002,unpublished.[2]R.Blair et al.,“The CDF II detector Technical Design Report”,preprintFERMILAB-Pub-96/390-E ,October 1996,unpublished.[3]ATLAS Collaboration,“ATLAS Detector and Physics Performance Tech-nical Design Report,V ol.I”,CERN publication CERN/LHCC 99-14,European Center for Particle Physics,Geneva,Switzerland (1999);ATLAS Collaboration,“ATLAS First Level Trigger Technical Design Report”,CERN publication CERN-LHCC-98-14,European Center for Particle Physics,Geneva,Switzerland (1998).[4]CMS Collaboration,“CMS:The TRIDAS Project.Technical Design Re-port,V ol.1:The trigger systems”,CERN publication CERN-LHCC-2000-038,European Center for Particle Physics,Geneva,Switzerland (2000).[5] D.Acosta et al.,“The CDF Cherenkov luminosity monitor”,Nucl.Instr.and Meth.,vol.A461,pp.540-544,2001.[6] F.Krueger and S.Hawke,“Calibration and On-Axis Characterization ofthe Source Projector Facility at the Radiation Physics Calibration Facility”,Fermilab Radiation Physics internal note 121,January 1996,unpublished.[7]Harshaw Chemical Company,Harshaw model 2000TLD reader:ThermoRMP ,6801,Cochran Road,Solon,OH 44139,USA,2000.The model 2000TLD reader used for these measurements at Fermilab was modiﬁed to extend the reading cycle to 10second.[8] D.Amidei et al.,“The silicon vertex detector of the Collider Detector atFermilab”,Nucl.Instr.and Meth.,vol.A350,pp.73-130,1994.[9]R.J.Tesarek et al.,“Measurement of the radiation environment in theCDF tracking volume”,accepted for publication in Nucl.Instr.and Meth.A ,2003.。

Guide to the Expression of Uncertainty in Measurement

Input and Output Quantities
In the generic model Y = f(X1,…,XN), the measurand is denoted by Y
Also called the output quantity
The quantities X1,…,XN are called input quantities
Remember: the correction term or factor itself has uncertainty
A small residual systematic error generally remains after all known corrections have been applied
Benefits
Much flexibility in the guidance Provides a conceptual framework for
evaluating and expressing uncertainty Promotes the use of standard terminology and
Stated Purposes
Promote full information on how uncertainty statements are arrived at
Provide a basis for the international comparison of measurement results
Uncertainty is a more practical concept Evaluating uncertainty allows you to place a

短语pointto的中文是什么意思

短语pointto的中文是什么意思短语point to的中文是什么意思point to这一个短语，我们首先要清楚它的中文意思是。

为此店铺为大家带来短语point to的中文意思。

短语point to的中文意思英 [pɔint tu:] 美 [pɔɪnt tu]1. 指向：PHP4 使用指派运算子(=) 可复制(copy)物件;使用传参考方式,会指向(point to)相同的物件.2. 被继承的类别称为基底类别(base class)、父类别或超类别(superclass继承基底类别的新类别称为子类别(subclass)、衍生类别(derived class)或扩充类别.2. 指出：1.在听读字词时,能在课文中指出(point to)所听到的字. 2.在听读字词时,能念出(read aloud)课文中的字. NA 高年段语言能力(1)-听(Listening)1.能听懂日常对话中的关键字词(key words)和句子.3.能於阅读时,3. 指着：43.clear up放晴,整理; | 44.point to指着; | 45.stay the night过夜;4. 指向,指出：play with以......为消遣,玩弄 | point to指向,指出 | prevent from预防,防止短语point to的单语例句1. I listed a few I had seen but then made the point that the most valuable technology here at Expo is " people to people " technology.2. The scale of group buying in China has reached a point where cracks have started to surface.3. The repair work so far is by and large to the point.4. Bears point to forecasts by economists that show Japan will contract twice as much as the US this year.5. " The point is to act properly in accordance with the rules, " Abou pointed out.6. Even though Cage was fearful of his and his family's safety he never at any point contemplated using violence to get rid of the intruder.7. At that point, these independent women think it is time to call it a day.8. Passengers will have to call a hotline or go to a particular taxi calling point to get a taxi in the future.9. He also didn't rule out calling Petraeus to testify on Benghazi at some point.10. Campion plans to tell the story from Brawne's point of view.短语point to的双语例句1. Methods According to the dissection features of transverse process and transverse process anteroartery, we point out that should be paid attention to treat No.3 lumbar vertebral transverse process syndrome with loosening therapy.根据腰椎横突、横突前动脉的解剖关系，指出松解疗法在治疗腰三横突综合征的`注意点。

Method of measuring the parallelism of the wheels

专利名称：Method of measuring the parallelism of the wheels of the front and rear axles ofautomotive vehicles as well as the set-backangles between the wheels of the front axleand the crab-angles, and apparatus forcarrying out this method发明人：Coetsier, Paul André申请号：EP82400003.8申请日：19820105公开号：EP0063057A1公开日：19821020专利内容由知识产权出版社提供专利附图：摘要：method and apparatus for measuring the parallelism of the front and rear wheels of motor vehicles, as well as the set back, and the static, dynamic and back. - at the level of each front wheel (1, 2) has a horizontal arm (3, 4) for angular sensors (20, 21) connected by a reference line (9), and each arm carries a transmitter (22)(5) a brush light (7a, 14a) reflected on a mirror (8.12) carried by the rear wheel (13,15), and on a photosensitive cell (14, 24).we obtain the angles of parallel and set back from the angular values determined by the sensors (20, 21) for successive train robberies.the invention allows control and resolve a series of angular parameters conveniently with interesting ways are relatively inexpensive.申请人：Etablissements M. Muller & Cie地址：50-56, rue des Tournelles F-75140 Paris Cedex 03 FR国籍：FR代理机构：Tony-Durand, Serge (FR)更多信息请下载全文后查看。

Towards a measurement of $phi_3$

a r X i v :h e p -e x /0305026v 1 13 M a y 2003Presented at XXXVIII Rencontres De Moriond:Electroweak Interactions and Uniﬁed TheoriesLes Arcs,France,March 15–22,2003TOW ARDS A MEASUREMENT OF φ3S.K.SWAINDepartment of Physics and Astronomy,University of Hawaii at Manoa,Honolulu,HI,USAResults on the decays B −→D CP K −,¯B0→D (∗)0¯K (∗)0,B 0→D ∗∓π±and their charge conjugates using data collected at the Υ(4S )resonance with the Belle detector at the KEKB asymmetric e +e −storage ring are reported.The implications for the determination of the weak phase φ3are discussed.1B −→D CP K −The extraction of φ31,an angle of the Kobayashi-Maskawa triangle 2,is a challenging mea-surement even with modern high luminosity B factories.Recent theoretical work on B meson dynamics has demonstrated the direct accessibility of φ3using the process B −→DK −3,4.If the D 0is reconstructed as a CP eigenstate,the b →c and b →u processes interfere.This interference leads to direct CP violation as well as a characteristic pattern of branching frac-tions.However,the branching fractions for D meson decay modes to CP eigenstates are only of order 1%.Since CP violation through interference is expected to be small,a large numberof B decays is needed to extract φ3.Assuming the absence of D 0−¯D0mixing,the observables sensitive to CP violation that are used to extract the angle φ35are,A 1,2≡B (B −→D 1,2K −)−B (B +→D 1,2K +)1+r 2+2r cos δ′cos φ3R 1,2≡R D 1,2Figure1:∆E distributions for(a)B−→D fπ−,(b)B−→D f K−,(c)B−→D1π−,(d)B−→D1K−,(e)B−→D2π−and(f)B−→D2K−.Points with error bars are the data and the solid lines show theﬁt results. Table1:Signal yields,feed-acrosses and ratios of branching fractions.The errors on R D are statistical andsystematic,respectively.B(B−→D0π−)events events feed-acrosswhere the ratios R D1,2and R D0are deﬁned asB(B−→D1,2K−)+B(B+→D1,2K+)R D1,2=,B(B−→D0π−)+B(B+→¯D0π+)D1and D2are CP-even and CP-odd eigenstates of the neutral D meson,r denotes a ratio of amplitudes,r≡|A(B−→¯D0K−)/A(B−→D0K−)|,andδis their strong phase diﬀerence. Note that the asymmetries A1and A2have opposite signs.We reconstruct D0mesons in the following decay channels.For theﬂavor speciﬁc mode(denoted by D f),we use D0→K−π+8. For CP=+1modes,we use D1→K−K+andπ−π+while for CP=−1modes,we use D2→Table2:Yields,partial-rate charge asymmetries and90%C.L intervals for asymmetries.B±→D f K±165.4±14.5179.6±150.04±0.06±0.03−0.07<A f<0.15B±→D1K±22.1±6.125.0±6.50.06±0.19±0.04−0.26<A1<0.38B±→D2K±29.9±6.520.5±5.6−0.19±0.17±0.05−0.47<A2<0.11M bc (GeV/c2)E v e n t s /(0.002 G e V /c 2)∆E (GeV)E v e n t s /(0.01 G e V )Figure 2:∆E (left)and M bc (right)distributions for the ¯B0→D 0¯K (∗)0candidates.Points with errors represent the experimental data,hatched histograms show the D 0mass sidebands and curves are the results of the ﬁts.Table 3:Fit results,branching fractions or upper limits at 90%C.L and statistical signiﬁcances for ¯B0→¯D ∗0¯K (∗)0.¯B0→D 0¯K031.5+8.2−7.627.0+7.6−6.95.0+1.3−1.2±0.65.1σ¯B 0→D 0¯K ∗041.2+9.0−8.541.0+8.7−8.14.8+1.1−1.0±0.55.6σ¯B 0→D ∗0¯K 04.2+3.7−3.02.7+3.0−2.4<6.61.4σ¯B 0→D ∗0¯K ∗06.1+5.2−4.58.6+4.2−3.6<6.91.4σ¯B 0→¯D 0¯K ∗01.4+8.2−7.69.2+7.7−7.2<1.8−¯B 0→¯D∗0¯K ∗01.2+4.1−3.60.0+3.9−3.2<4.0−E 2beam−| p D + p h |2,where p D and p h are the momenta of D 0and K −/π−candidates and E beam is the beam energy in the c.m.frame.The second is the energy diﬀerence,∆E =E D +E h −E beam ,where E D is the energy of the D 0candidate,E h is the energy of the K −/π−candidate calculated from the measured momentum and assuming the pion mass,E h =-0.200.20.40.60.81∆z (µm)A (∆z )0.20.40.60.811.2050010001500200025003000Integrated luminosity (fb -1)δs i n (2φ1+φ3)30 fb -1KEKBJuly, 2001200 fb -1KEKB 20042000 fb -1Super-KEKBFigure 3:(Left)Distribution of the asymmetry,A (∆z ),as a function of ∆z for the data with the ﬁt curve overlaid.(Right)Error on sin(2φ1+φ3),as a function of integrated luminosity.15MeV /c 2and 25MeV /c 2of the nominal D 0mass,respectively.In each channel we further deﬁne a D 0mass sideband region,with width twice that of signal region.For the π0from the D 0→K −π+π0decay,we require that its momentum in the CM frame be greater than 0.4GeV /c in order to reduce combinatorial background.D ∗0mesons are reconstructed in the D ∗0→D 0π0decay mode.The mass diﬀerence between D ∗0and D 0candidates is requiredto be within 4MeV /c 2of the expected value.¯K∗0candidates are reconstructed from K −π+pairs with an invariant mass within 50MeV /c 2of the nominal ¯K∗0mass.We then combine D (∗)0candidates with K 0Sor ¯K ∗0to form B mesons.For the ﬁnal result using 78fb −1data,a simultaneous ﬁt to the ∆E distributions for the three D 0decay channels taking into account the corresponding detection eﬃciencies 10.The ﬁt result is shown in Fig.2.The signal yields from the ﬁtting and the branching fractions are shown in Table 3.3B 0−¯B0mixing with B 0(¯B 0)→D ∗∓π±partial reconstruction.Since both Cabibbo-favoured (B 0→D ∗−π+)and Cabibbo-suppressed (¯B0→D ∗−π+)decays contribute to the D ∗−π+ﬁnal state,a time-dependent analysis can be used to measure sin(2φ1+φ3).Since the ratio of amplitudes is expected to be small (∼0.02),the CP asymmetry will be hard to observe,but may be possible since the B 0→D ∗−π+decay rate is fairly large.A ﬁrst step towards this measurement is the extraction of the mixing parameter ∆m d from B 0→D ∗−π+.We use events with a partially reconstructed B 0(¯B0)→D ∗∓π±candidates and where the ﬂavor of the accompanying B meson is identiﬁed by the charge of the lepton from aB 0(¯B0)→X ∓l ±νdecay.The proper-time diﬀerence between the two B mesons is deter-mined from the distance between the two decay vertices (∆Z ).From a simultaneous ﬁt to the proper-time distributions for the same ﬂavor(SF)and opposite ﬂavor(OF)event samples,we measure the mass diﬀerence between the two mass eigenstates of the neutral B meson to be ∆m d =(0.509±0.017(stat )±0.020(sys ))ps −1.The result is obtained using 29.1fb −1data collected with Belle detector at KEKB.This is the ﬁrst direct measurement of ∆m d using the technique of partial reconstruction.Fig.3(left)shows the mixing asymmetry A (∆Z )as a func-tion of ∆Z whereA (∆Z )≡N OF (∆Z )−N SF (∆Z )AcknowledgmentsWe wish to thank the KEKB accelerator group for the excellent operation of the KEKB accel-erator.References1.Another naming convention,γ(=φ3),is also used in the literature.2.M.Kobayashi and T.Maskawa,Prog.Theor.Phys.49,652(1973).3.M.Gronau and D.Wyler,Phys.Lett.B265,172(1991);D.Atwood,I.Dunietz andA.Soni,Phys.Rev.Lett.78,3257(1997);4.M.Gronau,hep-ph/0211282;5.H.Quinn and A.I.Sanda,Euro.Phys.J.C15,626(2000);6.A.Bornheim et al.(CLEO Collab.),hep-ex/0302026,submitted to Phys.Rev.D.;7.A.Abashian et al.(Belle Collab.),Nucl.Instr.and Meth.A479,117(2002).8.Hereafter,the inclusion of the charge conjugate mode decay is implied unless otherwisestated.9.S.K.Swain and T.E.Browder et al.(Belle Collab.),hep-ex/0304032,submitted to Phys.Rev.D.;10.P.Krokovny et al.(Belle Collab.),Phys.Rev.Lett.90,141802(2003);11.Y.Zheng et al.(Belle Collab.),hep-ex/0211065,to appear in Phys.Rev.D.;12.K.Hagiwara et al.,Review of Particle Physics,Phys.Rev.D66,010001(2002);024********16M(π+π-) (GeV/c 2)E v e n t s / (1 M e V /c 2)024681012R vert (cm)E v e n t s / (2 c m )0246810121416cos θK*E v e n t s-202468101214M(K -π+) (GeV/c 2)E v e n t s / (10 M e V /c 2)05D *0K-00510D *0K-*0020D -0K-*0010-0.2-0.100.10.2D -*0K-*0∆E (GeV)E v e n t s /(0.01 G e V )。

Literate Programming 教程说明书

Literate Programming using nowebTerry TherneauOctober11,20191IntroductionLet us change or traditional attitude to the construction of pro-grams.Instead of imagining that our main task is to instruct acomputer what to do,let us concentrate rather on explaining to hu-mans what we want the computer to do.(Donald E.Knuth,1984).This is the purpose of literate programming(LP for short).It reverses the ususal notion of writing a computer program with a few included comments,to one of writing a document with some embedded code.The primary organization of the document can then revolve around explaining the algorithm and logic of the code.Many diﬀerent tools have been created for literate programming,and most have roots in the WEB system created by D.Knuth[2].Some of these have been language speciﬁc,e.g.CWEB or PascalWeb;this article focuses on Norman Ramsey’s noweb,an simple LP tool that is language agnostic[3,1].Most R users will already be familiar with the basic structure of a noweb document,since the noweb system was the inspiration or Sweave.2Why use LP for SDocumentation of code is often an afterthought,particularly in a high level language like S.Indeed,I have one colleague who proclaims his work to be “self-documenting code”and eschews comment lines.The counter argument is proven any time we look at someone else’s code(what are they doing?),and in fact by looking at any of our own code after a lapse of time.When we write code the thought process is from an overall structure to algorithm to R function to code;the result is clear and simple as long as that overall structure remains in our thought,but reconstructing that milleau is not easy given the code alone. For a larger project like a package,documentation is even more relevant.When I make a change to the survival package I ususallyﬁnd that the revision is2/3 increased commentary and only1/3modiﬁed code,and a major portion of the time was spent puzzling out details that once were obvious.My use of LP methods was motivated by the coxme package.This is the most mathematically challenging part of the surival suite,and due to the need1to use sparse matrix methods it is algorithmically complex as well.It was one of the better programming decisions I’ve made.The old adage“more haste,less speed”holds for R code in general,but for packages and complex algorithms in particular.Many of you will have had the experience of puzzling over a coding or mathematics issue,thenﬁnally going to a colleage for advice.Then,while explaining the problem to them a solution suddenly becomes clear.The act of explaining was the key.In the same way, writing down and organizing the program logic within a document will get one to the endpoint of a working and reliable program faster.The literate programming literature contains more and better stated argu-ments for the beneﬁt of this approach.3CodingLike an Sweaveﬁle,the nowebﬁle consists of interleaved text and code chunks, the format is nearly identical.Here is theﬁrst section of the coxme code(after the document’s header and and an introduction).\section{Main program}The[[coxme]]code starts with a fairly standard argument list.<<coxme>>=coxme<-function(formula,data,weights,subset,na.action,init,control,ties=c("efron","breslow"),varlist,vfixed,vinit,sparse=c(50,.02),x=FALSE,y=TRUE,refine.n=0,random,fixed,variance,...){time0<-proc.time()#debugging lineties<-match.arg(ties)Call<-match.call()<<process-standard-arguments>><<decompose-formula>><<build-control-structures>><<call-computation-routine>><<finish-up>>}The arguments to the function are described below,omitting those that are identical to the\Verb!coxph!function.\begin{description}\item...The typeset code looks like this:2coxme =coxme<-function(formula,data,weights,subset,na.action,init,control,ties=c("efron","breslow"),varlist,vfixed,vinit,sparse=c(50,.02),x=FALSE,y=TRUE,refine.n=0,random,fixed,variance,...){time0<-proc.time()#debugging lineties<-match.arg(ties)Call<-match.call()process-standard-argumentsdecompose-formulabuild-control-structurescall-computation-routinefinish-up}In theﬁnal pdf document each of the chunks is hyperlinked to any prior or later instances of that chunk name.The structure of a noweb document is very similar to Sweave.The basic rules are1.Code sections begin with the name of the chunk surrounded by anglebrackets:<<chunk-name>>=;text chunks begin with an ampersand@.The primary diﬀerence with Sweave is that the name is required—it is the key to organizing the code—whereas in Sweave it is optional and usually omitted.There are no options within the brackets.2.Code chunks can refer to other chunks by including their names in anglebrackets without the trailing=sign.These chunks can refer to others, which refer to others,etc.In the created code the indentation of a ref-erence is obeyed.For instance in the above example the reference to “<<finish-up>>”is indented four spaces;when the deﬁnition ofﬁnish-up is plugged in that portion as a whole will be moved over4spaces.When the<<finish-up>>chunk is deﬁned later in the document it starts at the left margin.As an author what this means is that you don’t have to remember the indentation from several pages ago,and the standard emacs indentation rules for R code work in each chunk de-novo.3.Code chunks can be in any order.4.The construct[[x<-3]]will cause the text in the interior of the bracketsto be set in the same font as a code chunk.5.Include\usepackage{noweb}in the latex document.It in turn makes useof the fancyvrb and hyperref packages.36.One can use either.Rnw or.nw as the suﬃx on source code.If theﬁrst isused then emacs will automatically set the default code mode to S,but is not as willing to recognize C code chunks.If the.nw suﬃx is used and you have a proper noweb mode installed1,the emacs menu bar(noweb:modes) can be used to set the default mode for the entireﬁle or for a chunk.The ability to refer to a chunk of code but then to defer its deﬁnition until later is an important feature.As in writing a textbook,it allows the author to concentrate on presenting the material in idea order rather than code order.To create the tex document,use the R command noweave(file)where“ﬁle”is the name of the.Rnw source.It is necessary to have a copy of noweb.sty available before running the latex or pdﬂatex command,a copy can be found in the inst directory of the distribution.Optional arguments to noweave areout The name of the outputﬁle.The default is the name of the inputﬁle,with theﬁle extension replaced by“.tex”.indent The number of spaces to indent code from the left margin.The default value is1.To extract a code chunk use the notangle command in R.Arguments are ﬁle the name of the.Rnw sourceﬁle.target the name of the chunk to extract.By default,notangle will extract the chunk named“*”,which is usually a dummy at the beginning of theﬁle that names all the top level chunks.If this is not found theﬁrst named chunk is extracted.During extraction any included chunks are pulled in and properly indented.out The name of the outputﬁle.By default this will be the inputﬁlename with theﬁle extension replaced by“.R”.For Unix users the stand alone noweb package is an alternative route.I was not able toﬁnd a simple installation process for MacIntosh,and no version of the package at all for Windows.For R users the package option is simpler, although the standalone package has a longer list of options.Many of these, however,are concerned with creating cross-references in the printed text,which is mostly obviated by the hyperlinks.The noweave program will create a texﬁle with the exact same number of lines as the input,which is a help when tracking back any latex error messages —almost.The R version fails at this if the@that ends a code chunk has other text after the ampersand on the same line.Most coders don’t do this so it is rarely an issue.1The phrase proper noweb mode requires some explanation.The classic nw mode for emacs has not been updated for years,and does not work properly in emacs22or higher.However, in versions2and earlier of ESS Rnw mode was built on top of nw mode,and ESS included a noweb.elﬁle that was updated to work with later emacs versions.If you are using ESS2.15, say,then noweb mode worksﬁne.The newer ESS version12created Rnw mode from scratch, does not include a nowebﬁle,and emacs reverts to the old,non-working nw code.44Incorporation into RIn my own packages,noweb sourceﬁles are placed in a noweb directory.Myown style,purely personal,is to have source codeﬁles that are fairly small,2to10pages,because Iﬁnd them easier to edit.I then include a Makeﬁle:below isan example for a project with one C program and several R functions.makefile =PARTS=main.Rnw\basic.Rnw\build.Rnw\formula.Rnw\varfun.Rnw varfun2.Rnw\fit.Rnw\ranef.Rnw\lmekin.Rnw\bdsmatrix.Rnwall:fun docfun:../R/all.R../src/bds.cdoc:../inst/doc/sourcecode.pdfR=R--vanilla--slave../R/all.R:all.nwecho"require(noweb);notangle(’all.nw’)">$(R)echo"#Automatically created from all.nw by noweb">tempcat temp all.R>$@../src/bds.c:all.nwecho"/*Automatically created from all.nw by noweb*/">tempecho"require(noweb):notangle(’all.nw’,target=’bds’,out=’bds.c’)">$(R)$cat temp bds.c>$@../inst/doc/sourcecode.pdf:all.nwecho"require(noweb);noweave(’all.nw’)">$(R)texi2dvi--pdf all.texmv all.pdf$@all.nw:$(PARTS)cat($PARTS)>all.nwclean:-rm all.nw all.log all.aux all.toc all.tex all.pdf-rm temp all.R bds.cTheﬁrstﬁle“main”contains the deﬁnition of<<*>>=early on<<*>>=5<<bdsmatrix>><<ghol>><<print.bdsmatrix>>...listing the top level chuncks deﬁned in each of my sub-ﬁles,which in turn contain all the R function deﬁnitions.For a more sophisticated Makeﬁle that creates each function as a separate.Rﬁle look at the source code for the coxme package on Rforge.One can add a conﬁgure script to the top level directory of the package to cause this Makeﬁle to be run automatically when the package is built.See the source code for the coxme library for an example which had input from several CRAN gurus.I found out that it is very hard to write a Makeﬁle that works across all the platforms that R runs on,and this one is not yet perfected for that task—though it does work on the Rforge servers.When submitting to CRAN my current strategy is to run make all locally to create the documentation and functions from the nowebﬁles,and not include a configureﬁle.I then do a standard submission process:R CMD build to make the tar.gzﬁle for submission,R CMD check to check it thoroughly,and then submit the tarﬁle. 5DocumentationThis document is written in noweb,and found in the vignettes directory of my source ing a nowebﬁle as a vignette is very unusual—this may be the only case that ever arises—since the goal of noweb is to document source code and the goal of vignettes is to document usage of the function.We made use of the vignetteEngines facility available in R version3in order to use noweb instead of Sweave as the default engine for the document.The noweb function itself is written(not surprisingly)in noweb,and the pdf form of the code can be found in the inst/doc directory.References[1]Johnson,Andrew L.and Johnson,Brad C.(1997).Literate Programmingusing noweb,Linux Journal,42:64–69.[2]Donald Knuth(1984).Literate Programming.The Computer Journal(British Programming Society),27(2):97–111.[3]Norman Ramsay(1994).Literate programming simpliﬁed.IEEE Software,11(5):97–105.6。

河北省2024-2025学年高三上学期9月月考英语试题

河北省2024-2025学年高三上学期9月月考英语试题一、听力选择题1．What will the man probably do next?A．Make a cake.B．Take part in a race.C．Stop at the supermarket. 2．What does the man advise the woman to do?A．Take a few risks.B．Watch out for potential dangers.C．Avoid harming the natural system.3．What does the man intend to do?A．Buy a house.B．Expand his house.C．Advertise his house. 4．What are the speakers talking about?A．Drink orders.B．Items on the menu.C．Their favorite fruit. 5．Who is Elle most likely to be?A．Elena’s sister.B．John’s daughter.C．John’s elder sister.听下面一段较长对话，回答以下小题。

6．What do we know about Rob Brown?A．He will graduate next year.B．He takes an interest in cooking.C．He’s dissatisfied with Stacy’s service.7．What problem does Stacy find out?A．Rob clicked the wrong birth date.B．Rob selected the wrong year for his class.C．Rob didn’t know how to register for the course.听下面一段较长对话，回答以下小题。

The measurement and model construction of complex permittivity of vegetation

The complex permittivity of targeted objects is an important factor that influences its microwave radiation and scattering characteristics. In the quantitative research of microwave remote sensing, the study of the dielectric properties of the vegetation to establish the relationship between its specific physical parameters and complex permittivity is fundamental. In this study, six categories of vegetation samples were collected at the city of Zhangye, a key research area of the Heihe watershed allied telemetry experimental research. The vector network analyzer E8362B was used to measure the complex permittivity of these samples from 0.2 to 20 GHz by the coaxial probe technique. The research focused mainly on the corn leaves, and an empirical model was established between the gravimetric moisture and the real/imaginary parts of complex permittivity at the main frequency points of microwave sensors. Furthermore, the empirical model and the classical Debye-Cole model were compared and verified by the measured data collected from the Huailai County of Hebei Province. The results show that the newlyestablished empirical model is more accurate and more practical as compared to the traditional Debye-Cole model. microwave remote sensing, dielectric model, complex permittivity, corn leaves, coaxial probe technique

天麻酸奶中天麻素和天麻苷元含量的测定

武汉轻工大学学报Journai of Wuhan Polytechnio University V c S.38Nr.5Oct.2019第38卷第5期2019年10月文章编号：2095N386(2019)05-0006-06DOI：10.3969/j.issn.2095N386.2019.05.002天麻酸奶中天麻素和天麻＜元含量的测定黄先敏，甘会廷,韩立乾,孙建美（昭通学院农学与生命科学学院，云南昭通657000）摘要:以实验所做出的天麻酸奶为试验材料，对其中的天麻素和天麻昔元的含量进行测定分析，为天麻酸奶的生产利用和推广提供理论依据。

实验结果显示天麻与乳酸菌共同发酵后，发酵物中仍含有天麻素和天麻昔元。

关键词:天麻酸奶;天麻素;天麻昔元;含量;反相高效液相色谱法中图分类号:TS201.2文献标识码：AMeasurement of gastrodin and gastrodigenin in Gastrodia elata Bl yoghurt HUANG Xian-min.,GAN Hui-ting,HAN Li-qian,SUN Jian-mei(College of Agriculturo and Life Science,Zhaotong University,Zhaotong,657000,China)Abstract：The Gastrodia elata BI yoghurt made in laboratoro was used as the experimentai materiai,O s mecsure the content of gastrodin and gastrodioenin in Gastrodia elata BI yoghui powdco,which provided a theoreticoi basis fof the production,utilization and promotion of Gastrodia elata BI yorhuri.AOs the co-femientation of Gastrodia elata BI and lactic acid bacteaa,tar femientation product stili contains gastrodin and gastrodiaenia.Key words:Gastrodia elata BI%gastrodin%gastrodiaenin%content%reversed phass high perfomianco liquia chroma-iogoaphy1引言天麻（Gastuodia elatr BI）是我国传统名贵中药［1］，已有千年的药用历史，被誉为“治风之神药”&2-'（天麻中含有天麻素⑷、天麻昔元［5］、巴利森昔&6'、对k基苯甲醛切、对k基苯甲酸［8'及天麻多糖［9］等多种活性物质，其中主要的活性物质为天麻素和天麻昔元&10N1'。

高中英语选择性必修第一册Unit4BodyLanguageAssessingYourProgress

一、根据首字母填写单词(单词拼写)1. Humans can feel a speaker’s emotion from the t________ of his words. (根据首字母单词拼写)2. I have no choice but to b________ you to correct my mistakes in the material I attach to the letter. （根据首字母单词拼写）3. When asking a question or making a request, we use the modal verbs, such as “could”, “would” and “may” to soften the t______. (根据首字母单词拼写)二、根据汉语意思填写单词(单词拼写)4. Don't speak to me in that __________ (语气；口吻) of voice. (根据汉语提示单词拼写)5. Smith was so impressed by what she had done that he ________(询问) the girl’s name. （根据汉语提示单词拼写）6. I will ________(询问) when to begin our lessons. (根据汉语提示单词拼写)三、完成句子7. Have you ____________ the school life?你适应学校生活了吗?8. They stopped and ____________ in amazement.他们停下来，惊讶地盯着他。

四、根据所给汉语提示填空9. ________(无论什么困难) he may meet with, he will carry on his plan. （根据汉语提示完成句子）10. If the child has to ________(向前倾)when walking with a loaded pack,it is too heavy. （根据汉语提示完成句子）11. When you share a story with your friends, you care a lot more about how they________(反应) it. （根据汉语提示完成句子）五、句型转换12. I like the cheerful tone of New Year’s Day. （同义句转换）→I like the cheerful _________ of New Year’s Day.六、汉译英（单词/短语）(翻译)13. 汉译英1. ________ vt.意味着;暗示2. ________ vt.察觉;看待;理解3. ________ n.教师;教育工作者;教育家联想①________ n.教育②________ vt.教育;训练③________ adj.教育的;有教育意义的④________ adj.受过良好教育的;有教养的4. ________ adv.几乎不;勉强才能;刚刚联想 ________ adj.赤裸的;光秃秃的;空的;最低限度的5. ________ vt.占据;占用派①________ n.占领;职业;工作②________ adj.忙于……的;已被占用的6. ________ vi.盯着看;凝视n.凝视搭配 ________盯着看;凝视7. ________ vt.分散(注意力);使分心联想①________ n.使人分心的事物②________ vt.吸引③ ________ n.吸引力;吸引人之物;喜爱8. ________ n.焦虑;担心;害怕派①________ adj.焦虑的;担心的;渴望的;急切的②________ adv.焦虑地;担忧地9. ________ adj.难堪的;尴尬的联想①________ vt.使窘迫;使尴尬②________ adj.令人尴尬的;使人难堪的③________ n.尴尬;难堪10. ________ adv.只是;仅仅;只不过联想 ________ adj.仅仅;只不过七、汉译英（整句）(翻译)14. 微笑被认为是表示友好的有效方式。