Spin resonance transport properties of a single Au atom in S–Au–S junction and Au–Au–Au junction

The spin transport properties of S–Au–S junction and Au–Au–Au junction between Au nanowires are investigated with density functional theory and the non-equilibrium Green's function. We mainly focus on the spin resonance transport properties of the center Au atom. The breaking of chemical bonds between anchor atoms and center Au atom significantly influences their spin transmission characteristics. We find the 0.8 eV orbital energy shift between anchor S atoms and the center Au atom can well protect the spin state stored in the S–Au–S junction and efficiently extract its spin state to the current by spin resonance mechanism, while the spin interaction of itinerant electrons and the valence electron of the center Au atom in the Au–Au–Au junction can extract the current spin information into the center Au atom. Fermi energy drift and bias-dependent spin filtering properties of the Au–Au–Au junction may transform information between distance, bias,and electron spin. Those unique properties make them potential candidates for a logical nanocircuit.     

Charged particle fluctuation in Au+Au collision

In this paper,we present the centrality,transverse momentum region and rapidity window size dependence of charged particle fluctuation from Relativistic Quantum Molecular Dynamics （RQMD） model.D Q,Γ Q and Φ Q all depend on the rapidity windows we chosen.ν ＋-,dyn is a promising observable in experiments,it weakly depends on the acceptance.The beam energy dependence of ν ＋-,dyn has been studied to present baseline prediction for net charge fluctuations in experiments.     

Relative Distribution of Au48 ～ Au52 in Au Plasma by Ionization Dynamics

The present work proposes a theoretical method called ionization dynamics to derive the ionic charge state distribution. Using relativistic quantum mechanics to calculate the energy level lifetime and average ionic lifetime of each ion, the first-order ionization rate constant can be obtained. Based on these data, from the solution of differential equations for consecutive-irreversible ionization reactions, one will be able to derive the ionic charge state distribution.The calculated average positive charge 49.24 of Au48 ～ Au52 and their relative distribution are in good agreement with the results of Lawrence Livermore National Laboratory.     

600A MeV Au+Au碰撞的挤压效应分析

对６００ＡＭｅＶＡｕ＋Ａｕ碰撞实验的挤压效应进行了研究．在方位角分布分析的基础上,完成了对挤压效应的定量测量,有效地消除了估计反应平面离散对测量结果的影响．     

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利用考虑l能级分裂的屏蔽氢离子模型(SHML),计算高温(T=200~300eV)、高密度(ρ=1g.cm-3)下纯元素Au、Ho、Gd、Sm、Nd、Sn、Ag的Rosseland平均不透明度,以及Au与这些元素混合后的Rosseland平均不透明度,其结果与DCA/UTA及STA模型计算结果吻合较好。     

600A MeV Au+Au碰撞的挤压效应分析

对600A MeV Au+Au碰撞实验的挤压效应进行了研究.在方位角分布分析的基础上,完成了对挤压效应的定量测量,有效地消除了估计反应平面离散对测量结果的影响.     

超相对论Au+Au碰撞中椭圆流的时间依赖

用相对论量子分子动力学(RQMD)模型模拟了质心系束能量为s_NN=200GeV的Au+Au非对心碰撞, 研究了椭圆流对末态粒子冻出时间的关系. 研究了在不同的阶段, 椭圆流对末态粒子位置的关系. 结果表明椭圆流随冻出时间的单调递减, 椭圆流对横向半径的关系随冻出时间发生变化. 用压力梯度对所得结果进行了分析. 径向速度用来表征压力梯度.     

RHIC能区Au+Au碰撞中HBT关联参数分析

利用相对论量子分子动力学模型RQMD,对RHIC能区s=200GeV/u Au+Au碰撞进行了2π干涉学分析,并讨论了HBT半径参数对横动量的依赖关系.研究表明,两粒子关联函数能够给出碰撞源在冻结时刻的时空拓扑信息,HBT半径参数能够较好地反映源的尺度和形状,但其对横动量的依赖关系并不能直接反映源的压缩性质,而是对粒子产生时源的空间–动量关联程度更为敏感.     

Nuclear Shadowing Effect on the K Factor in Au—Au Collisions

We investigate the nuclear shadowing effect on the K factor in the Drell-Yan process by introducing a Shadowing factor into the corresponding quantum chromodynamical αs order corrections.K factors for Au-Au collisions are calculated at the centre-of-mass system energies √s=60,130 and 200 GeV while the nuclear shadowing factor is taken into account.The numerical results indicate that the nuclear shadowing factor obviously raises the K value in the small x region,and for the same nucleon the K valus becomes smaller as the energy increases.The nuclear shadowing effect could be one reason for creating the non-constancy of the K factor.     

Au/Au2S复合纳米球壳微粒的发光特性

观测了金纳米球壳微粒（纳米级Au2S介质外包裹一层纳米级厚的金壳）的荧光光谱，与块状Au2S的荧光峰相比，金纳米球壳的荧光峰蓝移到蓝绿区域，蓝移的主要原因是核－壳纳米复合结构中的表面态和量子尺寸效应。     

Au diffusion in α-Ti

The solubility and diffusion of Au in -Ti have been studied in a 823–1023 K temperature range using the Rutherford backscattering technique. For this purpose we have implanted Au into -Ti samples. Our results show that the solubility of Au varies between 0.2 and 0.35 at.%. In addition, we found that the diffusion coefficients follow a normal Arrhenius behavior with Q=260 kJ/mol and D _o=1.9×10^–5 m²/s¹. These values are typical for a substitutional diffusion mechanism.     

Investigation of ultra-thin and flexible Au–Ag–Au transparent conducting electrode

The performance of ultra-thin Au–Ag–Au tri-layer film deposited thermally over a flexible substrate is investigated using structural, optical, mechanical and electrical-transport measurements. The optimum total thickness of the tri-layer for high transparency and conductivity is determined to be around 8 nm using a theoretical model. The Au–Ag–Au tri-layer shows maximum transmittance (≅ 62%) at wavelength 500 nm. XRD pattern shows peak corresponding to (111) plane of Au and/or Ag. Sheet resistance (≅ 10.42 Ω/□) measured at 300 K using four probe technique is stable up to 150 °C. Hall effect measurements show high conductivity (1.34 × 10⁵ (Ω cm)⁻¹), carrier concentration (2.48 × 10²³/cm³), and mobility (3.4 cm²/Vs). Scotch tape test confirms good adhesion of the film onto PET substrate. Bending-twisting tests using an indigenous apparatus indicate high resistance-stability even after 50,000 cycles. These results imply the viability of Au–Ag–Au tri-layer film as a transparent conducting electrode worth exploring for optoelectronic applications.     

Λ-超子在RHIC的Au+Au碰撞中的整体极化

We present the Λ-hyperon global polarization in Au+Au collisions at s_NN=62GeV and 200GeV measured with the STAR detector at RHIC. The observed Λ-hyperon global polarization is consistent with zero, what is in agreement with recent measurements of Λ global polarization, as well as φ(1020) and K^*0(892) vector mesons spin alignment with respect to the reaction plane. The possible dependence of the global polarization on relative azimuthal angle between the orbital momentum of the system and the hyperon 3-momentum is discussed. The corresponding systematic uncertainty due to detector acceptance is found to be less than 20%.     

RHIC能区Au+Au非对心碰撞中的事件形状

利用相对论量子分子动力学模型RQMD,结合2π干涉学分析,对RHIC能区s=200AGeV Au+Au非对心碰撞的事件形状进行了研究.研究表明,HBT参数可以反映事件在坐标空间的非对称性,而不能直接给出事件在动量空间的压力梯度.另外,HBT参数对横动量的依赖关系对系统的空间–动量关联较为敏感.     

Transverse momenta of high-η charged particles emitted in Au+Au collisions

This work demonstrates that the mean transverse momentum of charged particles at large pseudo-rapidities can be reliably derived from measurements of the complete charged-particle multiplicity distributions and using information from measurements of p _T spectra at mid-rapidity by applying energy conservation requirements. As an example, the mean p _T of charged particles emitted at η=4.6 is found to be 〈p _T 〉=0.305 GeV/c for the 0–3% most central Au+Au collisions at $\sqrt {s_{NN} } = 130$ GeV.     

飞秒激光微加工Au膜

飞秒激光微加工薄膜对于MEMS设备的制造是一个急需的技术。文章使用波长为775 nm的Ti: sapphire飞秒激光器(脉宽约为130 fs, 频率为1 000 Hz)研究厚度为4 μm的Au薄膜,在不同加工参数下的结构特性,发现单脉冲消融时消融直径随着脉冲能量的增大而增大。当单脉冲能量一定时,消融直径随着脉冲的个数变化不大。计算得到Au膜的单脉冲消融阈值为F_th＝0.7 J·cm-2,使用脉冲能量略大于阈值时,在薄膜上所划出的线为凸起状;当超过阈值时所得直线为凹起状。同时发现在脉冲能量一定时所得线宽随着加工速度的增加而减小;当加工速度一定时线宽随着能量的增加而增大。     

RHIC能区Au+Au碰撞中集合径向流的研究

利用相对论量子分子动力学模型RQMD,对RHIC能区s=200A GeV Au+Au碰撞的集体膨胀效应进行了研究,对散射粒子的横质量谱进行了分析.研究表明,在RHIC能区的重离子反应中存在有强的集合径向流.对单粒子谱的拟合结果给出Au+Au的源冻结温度为160MeV,平均径向流速度为0.6c.     

Au/Au同质结的高压水热合成及其光学性能研究

本文通过水热法合成了Au和Au/Au同质结纳米粒子,并用透射电子显微镜(TEM)和紫外可见吸收(UV-vis)光谱对所合成的单分散Au纳米粒子和Au/Au同质结纳米粒子进行了表征。我们的研究发现,十六烷基三甲基溴化铵(CTAB)在Au/Au同质结纳米粒子的合成中起着非常重要的作用,改变CTAB的加入量,Au纳米粒子由单分散Au纳米粒子变成Au/Au同质结纳米粒子。     

Baryonic Effect on χcJ Suppression in Au＋Au Collisions at RHIC Energies

We predict that χcJ mesons at low transverse momentum in the central rapidity region are almost dissociatedby nucleons and antinucleons in hadronic matter produced in central Au Au collisions at relativistic high-ioncollider (RHIC) energies √^sNN = 130 and 200 GeV. In the calculations the nucleon and antinucleon distributionsin hadronic matter are results of evolution from their freeze-out distributions which well fit the experimentaltransverse momentum spectra of proton and antiproton.     

RHIC能区Au+Au碰撞中椭圆流的横半径依赖

用RQMD模型模拟了质心系束能量为s_NN=200GeV的Au+Au非对心碰撞, 研究了椭圆流对末态粒子冻出位置的关系. 研究表明, 随着冻出半径的增加, 椭圆流逐渐增强, 在源的初始表面处达到最大值, 随着冻出半径的继续增加, 椭圆流逐渐减小. 椭圆流的这种变化趋势反映了随着半径的增加, 压力梯度在各个方向上不同的变化. 本文提出了利用平均径向速度分析压力梯度的方法.