温度对金属纳米线势能分布的影响

采用三维分子动力学模拟方法,以面心立方金属银为研究对象,基于Finnis-Sinclair型嵌入原子法(EAM)多体势,模拟研究了纳米线势能分布特征在常温下及其在不同温度直到熔化过程中的变化,给出了常温及不同温度银纳米线势能分布比例和势能分布函数.结果表明:常温下,纳米线高势能原子比例随纳米线横截面尺寸的减小而增大,势能分布函数曲线各峰位几乎与纳米线横截面尺寸无关;纳米线熔化前的势能分布函数曲线具有多个波峰,随着温度增加,峰数减少且峰位右移;熔化后,多峰特征消失,只有一个宽化的峰.     

两种调制方式下主从激光器同步性能的理论研究

 以单周期信号为例，数值模拟并讨论了注入频率和注入光场波动强度对主从式半导体激光器同步性能的影响。分别通过直接调制和外部调制两种方式获得单周期信号，并采用改进的参数——相似指数评价系统的同步性能。研究结果表明：当注入强度足够大时，系统实现注入锁定同步，外部调制的相似指数大于内部调制；注入强度恒定时，同步品质几乎不受调制指数的影响，而受调制频率的影响；由于内部、外部调制引起主激光器的输出反相，两种调制方式下同步品质随调制频率的变化趋势也相反。     

基体改进-石墨炉原子吸收光谱法测定海水样品中痕量的铜

用石墨炉原子吸收光谱法测定海水中痕量铜.对基体改进剂进行了筛选,采用HNO3-酒石酸体系,克服了海水基体的干扰,并对试剂进行了空白对照实验.在确定了升温程序的基础上,用标准加入法测定样品.使用国家标准溶液作为质控样,对方法的精密度和准确性做了验证.     

Cyclic Heating-Annealing and Boltzmann Distribution of Free Energies in a Spin-Glass System

Ergodicity of a spin-glass is broken at low temperatures; the system is trapped in one of many ergodic configurational domains. Transitions between different ergodic domains are achievable through a heating-annealing procedure. If this experiment is repeated infinite times, all ergodic configurational domains will be visited with frequences that decreasing exponentially with their free energies. The mean free energy density of a spin-glass system on a random graph is calculated based on this free energy Boltzmann distribution in the present work, by means of the cavity approach.     

用传输线和时域有限差分法计算电缆X射线响应

 介绍了时域传输线和时域有限差分两种计算电缆X射线瞬态响应的方法，并利用电缆芯线总电荷以及介质层的电荷分布，结合实验结果，分别给出了时域传输线模型中的电流源和时域有限差分模型中电流密度的计算方法。作为例子，在60 keV单能X射线垂直于电缆轴向辐照的条件下，采用两种方法计算了电缆两端接匹配负载时负载上的电流响应；采用传输线方法计算了不同能量X射线辐照电缆时的芯线负载电流响应。计算结果表明，两种方法计算的电缆X射线瞬态响应是一致的；电缆介质层中存在静电场；X射线能量不同时，电缆芯线负载电流存在最大值。计算中，电缆与X射线的作用采用蒙特卡罗方法计算。     

一种基于角谱理论的光学FRFT的数值模拟算法

以角谱传播理论和分数傅里叶变换(FRFT)的单透镜和双透镜光学实现单元为理论基础,提出了一种基于实际光学结构的光学FRFT的数值模拟算法,推导了该算法中采样间隔的选取方法,并利用Matlab语言编写了相应的处理程序,将该程序对方孔分数傅里叶变换的计算结果与实际实验结果相比较,结果表明该算法是实际光学结构在理想情况下的模拟,因此,该数值计算在一定程度上可以代替柱面镜对光场实现分数傅里叶变换,也可以为实际实验提供很好的参考和指导。     

Coherent Scattering of Light by Bose-Einstein Condensation in a Tight Confinement

We have observed strong scattering of a probe light by dilute Bose-Einstein condensate （BEC） ^87Rb gas in a tight magnetic trap. The scattering light forms fringes at the image plane. It is found that we can infer the real size of the condensation and the number of the atoms by modelling the imaging system. We present a quantitative calculation of light scattering by the condensed atoms. The calculation shows that the experimental results agree well with the prediction of the generalized diffraction theory, and thus we can directly observe the phase transition of BEC in a tight trap.     

甾族化合物~(13)CNMR谱化学位移定量构谱关系的研究

利用原子电性距离矢量(Atomic Electro-negativity Distance Vector,AEDV)和原子杂化状态指数(Atomic Hybridization State Index,AHSI)对203个甾族化合物中4434个碳原子进行结构表征并与其核磁共振碳谱(13CNMR)建立多元线性定量结构波谱相关(QSSR)模型,同时运用逐步回归结合统计检测对模型变量进行筛选,最后采用内部及外部双重验证的办法对所得模型稳定性能进行深入分析和检验,建模计算值、留一法(leave-one-out,LOO)交互校验(cross-validation,CV)预测值和外部样本预测值的复相关系数(R)分别为0.9574、0.9571和0.9537.其结果表明,AEDV,AHSI与13CNMR谱化学位移显著相关.     

Quantum Stackelberg Duopoly of Continuous Distributed Asymmetric Information

The minimal quantization structure is employed to investigate the quantum version of the Stackelberg duopoly with continuous distributed asymmetric information, i.e a continuous distribution while the second mover has the first mover has incomplete information that obeys complete information. It is found that the effects of the positive quantum entanglement on the outcomes exhibit many interesting features due to the information asymmetry. Moreover, although the first-mover advantage is counteracted by the information asymmetry, the positive quantum entanglement still enhances the first-mover advantage and improves the first-mover tolerance of the information asymmetry beyond the classical limit.     

Resonances in Positron-He Scattering

We present the results for resonances in positron-He scattering at low impact energy （19.3-24.0eV） by using the momentum space coupled-channel optical （CCO） method. The S-partial wave resonance at 20.16 eV is found for the first time.