A plastic scintillating fiber position detector in vacuum for the test beam facility at BEPCⅡ-LINAC

Two plastic scintillating fiber position detectors for charged particles have been designed, built and installed inside the vacuum tube near two sides of the DM2 deflection magnet on the E3 beam line of the test beam facility at the BEPC-LINAC. A one-dimensional position resolution of sim 1 mm with a sensitive area of 60 mm×60 mm has been obtained for this detector.     

硫化学反应体系中的振荡与斑图形成

硫化学非线性反应体系是非线性化学的一个重要部分,在均相和反应扩散介质中均表现复杂自组织现象,尤其该类体系在前沿波作用、迷宫波及倍增分裂波研究和近几年斑图系统设计的突破起着关键作用。根据参与的物种数量将硫化学反应体系分为简单的两组分和三组分反应体系两大类。本文重点介绍了近三十年来这两类硫化学振荡器和反应-扩散斑图的研究进展,简述了该类反应体系在生物及其软物质领域的应用。最后,对硫化学振荡体系研究中存在的问题进行了探讨,并对今后的研究方向进行了展望。     

基于静力测量数据的随机梁式结构损伤识别

考虑模型误差和测量误差的影响,用概率的观念给出了静力荷载作用下梁式结构的模型误差和测量误差的定义,在此基础上,建立了关于损伤指数的随机控制方程.结合静力凝聚法和摄动法,给出了关于随机损伤指数的随机方程的求解方法.在获得随机损伤指数的解后,可通过结构损伤的概率定义对梁式结构损伤进行识别.最后利用几个数值算例验证了本文方法的有效性.     

Realization of double resonance for a bright frequency-tunable source of narrowband entangled photons

In this paper,we report an interesting phenomenon when precisely adjust the tuning crystal for double-resonance of a type-II configured parametric amplifier cavity,which is later verified as a cavity-enhanced effect in optics alignment.The theoretical result indicates that an angle accuracy error within 0.09 is necessary to achieve a high contrast ratio of 100:1 for a cavity with a finesse of about 205,which is crucial but high-demanding to get a high-quality narrowband entanglement source.Meanwhile,we figure out a method to release such a high requirement and get high visibility in a moderate-accuracy alignment.     

Evolution of Arbitrary States under Fock-Darwin Hamiltonian and a Time-Dependent Electric Field

The method of path integral is employed to calculate the time evolution of the eigenstates of a charged particle under the Fock-Darwin(FD) Hamiltonian subjected to a time-dependent electric field in the plane of the system.An exact analytical expression is established for the evolution of the eigenstates.This result then provides a general solution to the time-dependent Schro¨dinger equation.     

Unifying the crystallization behavior of hexagonal and square crystals with the phase-field-crystal model

By employing the phase-field-crystal models, the atomic crystallization process of hexagonal and square crystals is investigated with the emphasis on the growth mechanism and morphological change. A unified regime describing the crystallization behavior of both crystals is obtained with the thermodynamic driving force varying. By increasing the driving force, both crystals(in the steady-state) transform from a faceted polygon to an apex-bulged polygon, and then into a symmetric dendrite. For the faceted polygon, the interface advances by a layer-by-layer(LL) mode while for the apex-bulged polygonal and the dendritic crystals, it first adopts the LL mode and then transits into the multi-layer(ML)mode in the later stage. In particular, a shift of the nucleation sites from the face center to the area around the crystal tips is detected in the early growth stage of both crystals and is rationalized in terms of the relation between the crystal size and the driving force distribution. Finally, a parameter characterizing the complex shape change of square crystal is introduced.     

加磁场对GZO薄膜结构及光电性能的影响

采用射频磁控溅射法在玻璃基底上制备了Ga掺杂ZnO (GZO)薄膜,在传统磁控溅射系统中引入外加磁场,探究了磁场强度变化对GZO薄膜晶体结构和光电性能的影响.结果表明:所制得的GZO薄膜结构均为六角纤锌结构且在[002]方向沿C轴择优取向;外加磁场强度对薄膜的光电性能具有较大影响,在可见光范围内,薄膜的平均透光率超过93;,并出现了Moss-Burstein效应;薄膜的电学性能得到提升,其电阻率从4.96×10-3 Ω·cm降至3.17×10-4Ω·cm,霍尔迁移率从7.36cm2 ·V-1 ·S-1增至9.53 cm2·V-1·S-1.     

InAs/InxGa1－xSb二类超晶格红外探测器的吸收波长与电子-空穴波函数交叠的研究

运用包络函数模型和传输矩阵方法计算了二类超晶格的能级结构.考虑到InAs与In_xGa_1-xSb结合存在应变,在计算中InAs/In_xGa_1-xSb二类超晶格的带阶采用模型固体理论处理.因为吸收系数与电子-空穴波函数交叠成正比,所以研究了InAs/In_xGa_1-xSb二类超晶格红外探测器的吸收波 关键词： 二类超晶格 红外探测器 波函数的交叠 传输矩阵     

基于稳定Harris置信度的三步搜索数字稳像方法

提出一种基于稳定Harris角点置信度的三步搜索法数字稳像方法.采用三步搜索法策略进行运动参量的计算,对三步搜索法结果使用稳定Harris角点置信度进行约束,提升运动参量计算准确度.针对分辨率为320×240存在±40个像素范围内抖动的车载运动视频进行稳像处理,实验结果验证此方法有效可行.     

原子吸收光谱法测定龙葵果中微量元素的含量

采用炭化-湿式消解原子吸收光谱法测定龙葵果中的铜、铅、锌、镍、镓5种微量元素的含量,采用湿式消解原子荧光光谱法测定龙葵果中的锗的含量。龙葵果中Cu,Pb,Zn,Ni,Ga,Ge含量分别为13.82,2.51,35.62,2.86,0.016,0.16μg/g。龙葵果中各元素的回收率在99.08%—102.72%之间,RSD值在0.14%—2.78%之间,采用原子吸收光谱法测定几种微量元素稳定性好,结果准确可靠。作为药食两用的植物龙葵果含丰富的矿物质元素,对人体补充微量元素有较高的利用价值。