共查询到19条相似文献,搜索用时 125 毫秒
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Au电极厚度对MgZnO紫外探测器性能的影响 总被引:1,自引:0,他引:1
利用分子束外延设备(MBE)制备了MgZnO薄膜.X射线衍射谱、紫外-可见透射光谱和X射线能谱表明薄膜具有单一六角相结构,吸收边为340 nm,Zn/Mg组分比为62:38.采用掩膜方法使用离子溅射设备,在MgZnO薄膜上制备了Au电极,并实现了Au-MgZnO-Au结构的紫外探测器.通过改变溅射时间,得到具有不同Au电极厚度的MgZnO紫外探测器.研究结果表明:随着Au电极厚度的增加,导电性先缓慢增加,再迅速增加,最后缓慢增加并趋于饱和;而Au电极的透光率则随厚度的增加呈线性下降.此外,随着Au电极厚度的增加,器件光响应度先逐渐增大,在Au电极厚度为28 nm时达到峰值,之后逐渐减小. 相似文献
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用强子–弦级联模型JPCIAE及相应的Monte Carlo事例产生器研究相对论性核–核碰撞中带电粒子多重数的赝快度密度对能量和中心度的依赖关系.无需另调任何模型参数的条件下,此模型可以同时较好地描述相对论性pp实验数据及PHOBOS和PHENIX实验组的Au+Au实验数据.本文指出:因〈Npart〉并非严格定义的物理量,致使实验上和理论上确定〈Npart〉有一定任意性,从而使得每参加者核子对的带电粒子赝快度密度随着〈Npart〉的增加可能逐渐增大,也可能逐渐减小,因此用它来区分粒子产生机制是欠妥的. 相似文献
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研究了碱土金属氧化物对Bi离子掺杂RO-Al2O3-SiO2 (R=Ca, Sr, Ba)玻璃近红外超宽带发光性质的影响. 结果表明: 玻璃样品在不同抽运源激发下都可检测到较强的近红外超宽带发光. 在808 nm激光激发下, 随着碱土金属离子半径的增加, Bi离子在1 300 nm附近的近红外发光强度显著增加, 荧光半高宽逐渐增加, 其荧光寿命最长可超过600 μms; 而在690 nm激光激发下, 随着碱土金属离子半径的增加, Bi离子在1 100 nm附近的近红外发光呈减弱趋势, 荧光半高宽逐渐增大, 半高宽最大可超过400 nm. 近红外发光可能源于两种不同形式铋的发光中心. 针对上述结果探讨了该玻璃体系中Bi离子近红外发光的机理. 相似文献
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利用时域有限差分法研究了Au纳米天线对GaSb纳米线的消光增强.通过分析不同形状Au纳米阵列的电场特性和光学特性,发现三角形为最优结构,并具有高强度共振吸收峰和高的电场增强倍数.分别对三角形尺寸和纳米线的间距进行调节,结果表明:随着尺寸由70nm增加到210nm,消光峰位从783nm单调增加到1 638nm,峰位强度和电场增强倍数逐渐增加,尺寸为210nm时的增强倍数为70nm时的6倍;随着间距由80nm增加到130nm,消光峰位从1 655nm减小到1 460nm,峰位强度和电场增强倍数略微减小.因此可通过先调节间距再调节尺寸的方法来设计Au纳米天线结构. 相似文献
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利用超高真空扫描隧道显微镜, 在低温(80 K)下研究了同分异构体分子Dy@C82在Au(111)表面的吸附与分子取向.在低覆盖度下,Dy@C82分子优先吸附于台阶边缘形成分子团簇与分子链结构.这种吸附取决于分子-衬底的相互作用,并存在多种不同的分子取向.增大分子覆盖度后,Dy@C82在金表面形成二维有序密排的单层膜结构.Dy@C82分子在金表面的取向倾向于其C2长轴与金表面近乎平行.具有三种取向的分子最具优势,而同种取向的分子组成许多局限于一个个小区域内的取向有序结构畴.随着覆盖度的增加,Dy@C82分子在Au(111)表面趋向于短程有序取向排列,这是由分子-衬底作用与分子间的偶极-偶极作用共同决定的. 相似文献
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按照夸克随机组合的简单组合模型, 本文通过分析得出重子反重子比率与夸克反夸克平均产生几率的关系. 进一步计算了相对论重离子碰撞过程中各种反粒子与粒子的比率, 不需要任何额外假定, 预言的比率与RHIC加速器√SNN=130GeV时Au+Au碰撞STAR实验的结果基本一致. 表明夸克组合模型能够解释相对论重离子碰撞过程的反粒子与粒子比率. 相似文献
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M. Zawisza 《Indian Journal of Physics》2011,85(7):1051-1056
Correlations between non-identical particles at small relative velocity probe asymmetries in the average space-time emission
points at freezeout [1]. Such asymmetries may arise from long-lived resonances, bulk collective effects, or differences in
the freezeout scenario for the different particle species. STAR has extracted pion-proton correlation functions from a high-statistics
dataset of Au+Au collisions at ?{sNN }\sqrt {s_{NN} } = 200 GeV. We present a femtoscopic analysis of this data for all combinations of charged pions and (anti-) protons, for
collisions of different centrality. The measurements are compared with calculations of a simple Blast-wave model, in which
asymmetries are driven only by collective flow, as well as with Therminator [2], which also accounts fully for resonance effects. 相似文献
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Effects of density-and momentum-dependent potentials in Au+Au collisions at intermediate energies 下载免费PDF全文
Based on an isospin-dependent transport model, the effects of the density-and momentum-dependent potentials are studied by simulating Au on Au collisions at 90, 120, 150 and 400 MeV/nucleon. It is found that the calculated results overestimate the experimental data on the directed flow and underestimate the data on the elliptic flow for protons. The impact of the density-and momentum-dependent potentials is observed in the mid-rapidity region of the final spectra. At 90 MeV/nucleon, the momentum-dependent potential has a larger impact on the observables than the density-dependent potential, and the elliptic flow has a higher value with the positive effective mass splitting. At 400 MeV/nucleon, however, the opposite is observed. The rapidity dependence of the elliptic flow for protons is sensitive to the symmetry energy. A soft symmetry energy corresponds to a higher value of the proton elliptic flow. 相似文献
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Ackermann KH Adams N Adler C Ahammed Z Ahmad S Allgower C Amsbaugh J Anderson M Anderssen E Arnesen H Arnold L Averichev GS Baldwin A Balewski J Barannikova O Barnby LS Baudot J Beddo M Bekele S Belaga VV Bellwied R Bennett S Bercovitz J Berger J Betts W Bichsel H Bieser F Bland LC Bloomer M Blyth CO Boehm J Bonner BE Bonnet D Bossingham R Botlo M Boucham A Bouillo N Bouvier S Bradley K Brady FP Braithwaite ES Braithwaite W Brandin A Brown RL Brugalette G Byrd C Caines H 《Physical review letters》2001,86(3):402-407
Elliptic flow from nuclear collisions is a hadronic observable sensitive to the early stages of system evolution. We report first results on elliptic flow of charged particles at midrapidity in Au+Au collisions at square root(S)NN = 130 GeV using the STAR Time Projection Chamber at the Relativistic Heavy Ion Collider. The elliptic flow signal, v2, averaged over transverse momentum, reaches values of about 6% for relatively peripheral collisions and decreases for the more central collisions. This can be interpreted as the observation of a higher degree of thermalization than at lower collision energies. Pseudorapidity and transverse momentum dependence of elliptic flow are also presented. 相似文献
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Within the framework of the UrQMD model, by tracing the number of initial quarks in protons, we study the elliptic flow of protons with 3, 2, 1, 0 initial quarks and anti-protons in Au+Au collisions at SNN~(1/2)= 7.7, 11.5, 39,200 GeV. The difference of elliptic flow between protons with 2, 1, 0 initial quarks and anti-protons is smaller than 0,or consistent with 0, respectively. The difference of elliptic flow between transported protons(with 3 initial quarks)and anti-protons is larger than 0 at 7.7, 11.5 and 39 GeV. This is in good agreement with the STAR results at 7.7 and 11.5 GeV, but overestimates the STAR results at 39 GeV. The yield of transported protons with 3 initial quarks is smaller than of protons with 2 and 1 initial quarks, and v_2 of all protons is much smaller than the STAR results. The observation of the v_2 difference of elliptic flow between transported protons and anti-protons in the UrQMD model partly explains the difference between protons and anti-protons observed in the Beam Energy Scan program at the Relativistic Heavy Ion Collider(RHIC). 相似文献
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Adcox K Adler SS Ajitanand NN Akiba Y Alexander J Aphecetche L Arai Y Aronson SH Averbeck R Awes TC Barish KN Barnes PD Barrette J Bassalleck B Bathe S Baublis V Bazilevsky A Belikov S Bellaiche FG Belyaev ST Bennett MJ Berdnikov Y Botelho S Brooks ML Brown DS Bruner N Bucher D Buesching H Bumazhnov V Bunce G Burward-Hoy J Butsyk S Carey TA Chand P Chang J Chang WC Chavez LL Chernichenko S Chi CY Chiba J Chiu M Choudhury RK Christ T Chujo T Chung MS Chung P Cianciolo V Cole BA D'Enterria DG 《Physical review letters》2002,89(21):212301
Two-particle azimuthal correlation functions are presented for charged hadrons produced in Au+Au collisions at the Relativistic Heavy Ion Collider (sqrt [s(NN)]=130 GeV). The measurements permit determination of elliptic flow without event-by-event estimation of the reaction plane. The extracted elliptic flow values (v2) show significant sensitivity to both the collision centrality and the transverse momenta of emitted hadrons, suggesting rapid thermalization and relatively strong velocity fields. When scaled by the eccentricity of the collision zone epsilon, the scaled elliptic flow shows little or no dependence on centrality for charged hadrons with relatively low p(T). A breakdown of this epsilon scaling is observed for charged hadrons with pT >1.0 GeV/c. 相似文献
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Eccentricity and elliptic flow at fixed centrality in Au+Au collisions at sNN=200 GeV in AMPT model 下载免费PDF全文
In this paper, elliptic flow is studied at fixed centrality in Au+Au collision at √sNN=200 GeV in the AMPT model. It is observed that with the participant increasing, elliptic flow has an increase or a decrease at different fixed impact parameter, but it does not have a trivial fluctuation. It is analyzed that the initial space anisotropy dominates the participant dependence of elliptic flow in near-central collisions(b=5 fm) and mid-central collisions(b=8 fm), while the interaction between particles can mainly answer for the behavior of elliptic flow with participant in peripheral collisions (b=12 fm). To distinguish the pure geometrical effect, elliptic flow scaled by initial eccentricity is studied. It is found that the ratio v2/ε increases with participant and reaches a saturation when the participant is large enough, indicating that the collision system may reach the local equilibrium. 相似文献
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R. Andrade A. dos Reis F. Grassi Y. Hama T. Kodama J. -Y. Ollitrault W. -L. Qian 《Indian Journal of Physics》2010,84(12):1657-1661
Hydrodynamics has been rather successful at describing results obtained in relativistic nuclear collisions at RHIC. Here we
show results obtained with NeXSPheRIO on Au+Au collisions and the less studied Cu+Cu collisions. We study elliptic flow and
its connection with eccentricity suggested by PHOBOS, as well as present elliptic flow fluctuations. We also show results
for directed flow and compare with PHOBOS and STAR data. 相似文献
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Afanasiev S Aidala C Ajitanand NN Akiba Y Alexander J Al-Jamel A Aoki K Aphecetche L Armendariz R Aronson SH Averbeck R Awes TC Azmoun B Babintsev V Baldisseri A Barish KN Barnes PD Bassalleck B Bathe S Batsouli S Baublis V Bauer F Bazilevsky A Belikov S Bennett R Berdnikov Y Bjorndal MT Boissevain JG Borel H Boyle K Brooks ML Brown DS Bucher D Buesching H Bumazhnov V Bunce G Burward-Hoy JM Butsyk S Campbell S Chai JS Chernichenko S Chiba J Chi CY Chiu M Choi IJ Chujo T Cianciolo V Cleven CR 《Physical review letters》2007,99(5):052301
Differential elliptic flow (v(2)) for phi mesons and (anti)deuterons (d)d is measured for Au+Au collisions at square root of sNN=200 GeV. The v(2) for phi mesons follows the trend of lighter pi+/- and K+/- mesons, suggesting that ordinary hadrons interacting with standard hadronic cross sections are not the primary driver for elliptic flow development. The v(2) values for (d)d suggest that elliptic flow is additive for composite particles. This further validation of the universal scaling of v(2) per constituent quark for baryons and mesons suggests that partonic collectivity dominates the transverse expansion dynamics. 相似文献