高压下Al0.77Mn0.19Yb0.04合金准晶T相的形成及结构

利用静高压(4.2GPa)熔态(1300℃)淬火(10~2℃/S)方法,对含稀土的铝锰合金Al_(0.77)Mn_(0.10)Yb_(0.04)进行了研究。首次发现了准晶T相的形成。利用选区透射电子衍射技术,对合金中准晶态的结构对称性进行了观察和分析。根据X射线和电子衍射对其衍射峰进行了指标化。使用扫描电镜和能谱技术进行了成份分析。     

Conductance in normal metal/insulator/ferromagnetic superconductor tunnel junctions

In this paper, the superconducting order parameter and the energy spectrum of the Bogoliubov excitations are obtained from the Bogoliubov-de Gennes equation for a ferromagnetic superconductor (FS). In the framework of the Blonder-Tinkham-Klapwijk model, we present the differential conductance of the normal metal/insulator/FS junctions. It is shown that the exchange energy h in the FS can lead to the Zeeman splitting of the conductance peaks and the energy difference between the two splitting peaks is equal to 2h. The observation of such Zeeman splitting in the conductance spectrum can be taken as evidence for the coexistence between superconductivity and ferromagnetism.     

我国范围内多个再分析地表通量数据集的可信度分析

利用NCEP/NCAR(NCEP1)、NCEP/DOE(NCEP2)及ECMWF的再分析地表通量(感热和潜热通量)资料,以及由经验公式计算得出的我国地表通量的气候值(以下简称气候值),采用可视化分析、统计分析和天气气候学诊断方法,分析了三组再分析数据集的地表感热、潜热通量,以及基于地表热通量的鲍文比和地表热源在不同季节的空间分布和年变化,并与气候值做了比较.结果显示,尽管存在一些共同的问题(如三组再分析数据集潜热通量的值明显偏大),但不同再分析地表通量所反映的我国不同季节地表感、潜热通量的空间分布和年变化趋势与气候值的分布是一致的.总的来看,ECMWF再分析是最合理的,其次为NCEP2,最后为NCEP1.     

The effect of two-photon absorption and optical excitation area on the generation of THz radiation

It was found experimentally that the THz radiation throughput based on optical rectification is strongly related to the optical excitation size in a ZeTe emitter. The factors affecting the THz radiation throughput are investigated in detail both experimentally and theoretically. By taking into account optical rectification, diffraction and two-photon absorption effects, a theoretical model is established to describe the emitting field intensity of THz radiation. There is excellent agreement between the theoretical results and the experimental data under high excitation power. Both theoretical and experimental results demonstrate that there is a trade-off between these three effects for THz radiation, and that in order to increase the THz radiation throughput based on optical rectification, one should choose suitable excitation size under a given pump power.     

Synthesis of single crystalline GaN nanoribbons on sapphire (0001) substrates

Single crystalline GaN nanoribbons were synthesized through nitriding Ga₂O₃ thin films deposited on sapphire (0001) substrates by radio frequency magnetron sputtering. The component and structure of nanoribbons were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX), transmission electron microscopy (TEM) and high-resolution transmission electron microscopy (HRTEM). The flat and smooth ribbon-like nanostructures are high quality single crystalline hexagonal wurtzite GaN. The thickness and width-to-thickness ratio of the grown GaN nanoribbons are in the range of 8-15 nm and ∼5-10, respectively.     

Assembly of Ag（I） Polymers with Thioether-S Binding and Homochiral Helices

A novel coordination polymer [Ag(pyta)]n (pyta^-=4-pyridylthioacetate) containing bound thioether sulfurs and single-stranded helical chains has been synthesized and structurally characterized.     

大气环境下氦气等离子体中化学过程数值模拟

建立一个大气化学程序用以模拟大气压下（地面附近）或低压（高空）情况下混合气体（氦气中混入少量空气）中产生等离子体后的化学过程。给出了电子寿命和主要带电粒子的随时间演化图。电子寿命在大气压下要长于大气等离子体，但在低压情况下这个结论不成立。电子数密度在一很长一段时间内不服从指数衰减规律。     

Cr^4＋：YAG的可饱和吸收特性与被动Q开关性能研究

运用速率方程计算了Ｃｒ＾４＋：ＹＡＧ晶体的可饱和吸收特性参数，包括初始吸收系数，饱和吸收系数，饱和光强和损耗调制度，用Ｃｒ＾４＋：ＹＡＧ对脉冲和连续Ｎｄ：ＹＡＧ激光器进行了被动调Ｑ，在脉冲Ｎｄ：ＹＡＧ激光器上得到了８ｎｓ的调Ｑ激光脉冲，在连续Ｎｄ：ＹＡＧ激光器的调Ｑ中得到了间隔和幅度抖动小于５％的输出脉冲充列。     

Deterministic inventory model for deteriorating items with capacity constraint and time-proportional backlogging rate

In this paper, a deterministic inventory model for deteriorating items with two warehouses is developed. A rented warehouse is used when the ordering quantity exceeds the limited capacity of the owned warehouse, and it is assumed that deterioration rates of items in the two warehouses may be different. In addition, we allow for shortages in the owned warehouse and assume that the backlogging demand rate is dependent on the duration of the stockout. We obtain the condition when to rent the warehouse and provide simple solution procedures for finding the maximum total profit per unit time. Further, we use a numerical example to illustrate the model and conclude the paper with suggestions for possible future research.     

Copolymers of 2,5‐bis[(4‐methoxyphenyl) oxycarbonyl]styrene with n‐butyl acrylate: Design,synthesis, and characterization

A series of rod–coil diblock copolymers, consisting of poly{2,5‐bis[(4‐methoxyphenyl)oxycarbonyl]styrene} as a rigid segment and poly(n‐butyl acrylate) as a flexible part, were successfully prepared through two inverse procedures by atom transfer radical polymerization. The copolymers were characterized by ¹H NMR and gel permeation chromatography and had high molecular weights and relatively narrow polydispersities (polydispersity index < 1.20). All the block copolymers synthesized had two distinct glass‐transition temperatures according to differential scanning calorimetry. A polarizing optical microscopy investigation demonstrated the liquid crystallinity of the diblock copolymers. The self‐assembly behaviors in dilute solutions was studied by transmission electron microscopy. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 5935–5943, 2005