碘化钠NaI(Tl)单晶闪烁探测器的应用

碘化钠NaI(Tl)单晶闪烁探测器由射线探测器、计算机多道、高压电源及线性放大器、计算机多道脉冲幅度分析器等部分组成。当放射源发出的γ射线进入闪烁体时,γ光子即与闪烁体中的原子、分子及晶体系统发生相互作用(如光电效应,康普顿散射和电子对效应等)。     

含Dzyaloshinski-Moriya相互作用的三量子位HeisenbergXX链的热纠缠

研究了外加磁场下具有Dzyaloshinski-Moriya(DM)各向异性反对称相互作用的三量子位Heisenberg XX链的对热纠缠以及在热平衡下用该链作为信道来传输未知的量子态。详细地给出了磁场、DM相互作用及温度对热纠缠和平均传输保真度的影响。结果表明:磁场和DM相互作用可以有效地调控对热纠缠;在温度较低情况下,关闭磁场和DM相互作用,顺铁磁链可以很好地用来做隐形传态的信道;纠缠不能完全反映平均传输保真度,相同的纠缠可以导致不同的平均传输保真度。     

Simple schemes for generation of W-type multipartite entangled states and realization of quantum- information concentration

We propose simple schemes for generating W-type multipartite entangled states in cavity quantum electrodynamics (CQED). Our schemes involve a largely detuned interaction of Λ-type three-level atoms with a single-mode cavity field and a classical laser, and both the symmetric and asymmetric W states can be created in a single step. Our schemes are insensitive to both the cavity decay and atomic spontaneous emission. With the above system, we also propose a scheme for realizing quantum-information concentration which is the reverse process of quantum cloning. In this scheme, quantum-information originally coming from a single qubit, but now distributed into many qubits, is concentrated back to a single qubit in only one step.     

跨声速离心压气机机匣处理扩稳研究

高增压技术是高升功率车用内燃机的主要技术瓶颈之一,其核心难点在于高压比离心压气机内部复杂跨声速流动导致稳定运行范围窄,无法满足车用工况在高压比条件下对稳定运行工作范围的要求。为拓宽跨声速离心压气机的稳定工作范围,利用全三维数值模拟研究了机匣处理几何参数对扩稳的作用规律及机理。试验结果表明,采用优化后的机匣处理结构,压气机稳定工作范围由20.8%提高到33.6%。     

Narrow Linewidth Tm^3＋-Doped Large Core Fiber Laser Based on a Femtosecond Written Fiber Bragg Grating

A diode laser （LD） clad-pumped narrow linewidth all-fiber Tm^3＋-doped fiber laser is reported with a maximal output power of 27W at 1.947μm. By successively splicing an LD pigtail fiber, a single-mode Tm^3＋-doped fiber, and a multi-mode Tm^3＋-doped fiber, the fiber laser has 70pm narrow linewidth output, and a high slope efficiency of nearly 47.5% with respect to the launched pump power. The high reflectivity fiber Bragg gratings, which are directly written into the single-mode Tm^3＋-doped fiber core by the 800nm femtosecond pulsed laser, act as the high reflectivity coupler. The output laser has diffraction-limited beam quality with a factor M^2 of 1.29, when the output laser power is nearly 27W.     

时滞变质品供应链的数量折扣协调模型

在由单个批发商与单个零售商组成的两级时滞变质品供应链中,分别建立分散决策和集中决策下供应链系统的单位时间利润函数,通过比较得到集中决策优于分散决策的条件。引入数量折扣契约对时滞变质品供应链进行协调,促使整个供应链系统实现集中决策下的最优状态。设计收益共享合同来合理分配协调后的利润增量,保证批发商和零售商的单位时间利润都比协调前有所增加,从而实现供应链系统的帕累托改善。最后,通过数值算例演示了两种决策模式的单位时间利润情况,并分析了关键参数对供应链系统及各成员企业单位时间利润水平的影响。     

L\"{u}roth展式中数字和的快速增长速度[英文]

我们研究L\"{u}roth展式中数字和的快速增长速度,并证明相关水平集的Hausdorff维数是满维的.     

甲磺酸培氟沙星与氯冉酸的荷移反应

利用甲磺酸培氟沙星与氯冉酸在甲醇介质发生荷移反应,建立了荷移分光光度法测定甲磺酸培氟沙星含量的方法。结果表明,荷移反应生成1∶1型配合物,最大吸收波长为530nm,甲磺酸培氟沙星线性范围为2.25×10-8—3.38×10-6mol/L浓度内,回收率为98.7%—101.4%。     

First-principles study on the geometric and electronic structures and phase transition of PbZr1-xTixO3 solid solutions

With first-principles virtual-crystal approximation calculations, we systematically investigate the geometric and elec- tronic structures as well as the phase transition of lead zirconate titanate (PbZr1-xTixO3 or PZT) as a function of Ti content for the whole range of 0 ≤ x Ti ≤ 1. It can be found that, with the increase of the Ti content, the PbZr1-xTixO3 solid solu- tions undergo a rhombohedral-to-tetragonal phase transition, which is consistent with the experimental results. In addition, we also show the evolution in geometric and electronic structures of rhombohedral and tetragonal PbZr1-x TixO3 with the increasing content of Ti.     

Large-Quantity Synthesis of Single-Crystalline Metal Indium Nano/Sub-Micron Wires

Large quantities of metal indium single-crystalline wires with diameters ranging from tens of nanometres to a few micrometres were synthesized on Si substrates. Unlike traditional methods for the fabrication of nanowires or nanorods, liquid indium was squeezed out of the pores and cracks from porous an InAlN layer to form the wires. Continuous pushing out of liquid metal indium under strength, lowering of liquid-solid interfaces and the confinement of the cracks all contribute to the growth of indium wires. Our experiments have shed some light on the possibility of synthesizing large quantities quasi-1D nano/sub-micron structures with specified cross-sectional geometry using the similar method.