Quantum reflection of a Bose-Einstein condensate with a dark soliton from a step potential

We study dynamical behaviors of a Bose-Einstein condensate (BEC) containing a dark soliton reflected from potential wells and potential barriers, respectively. The orientation angle of the dark soliton and the width of the potential change play key roles on the reflection probability R_s. Variation of the reflection probability with respect to the orientation angle θ of the dark soliton can be well described by a cosine function R_s~cos[λ(θ-π/2)], where λ is a parameter determined by the width of the potential change. There are two characteristic lengths which determine the reflection properties. The dependence of the reflection probability on the width of the potential change shows distinct characters for potential wells and potential barriers. The length of the dark soliton determines the sensitive width of potential wells, whereas for potential barriers, the decay length of the matter wave in the region of the barrier qualifies the sensitive width of the barrier. The time evolution of the density profiles of the system during the reflection process is studied to disclose the different behaviors of matter waves in the region of the potential variation.     

一类非线性压缩生成的不变集的局部维数

本文以有界变差原理和有界畸变原理为工具,讨论了满足开集条件,且二次可微的一族递增的非线性压缩映射所产生的不变集的局部维数。     

氨基酸对映体的手性薄层色谱拆分

设计并制备了３,５－二硝基苯甲酰基取代的β－环糊精薄层色谱键合固定相,用于拆分丹磺酰化氨基酸对映体。该键合相合成方法简单,性能稳定,适用于正相和反相液相色谱。以乙腈－１％（ψ）乙酸三乙胺－乙酸为展开系统,８对丹磺酰化氨基酸对映体得到良好分离,对映异构体之间的相对比移植α为１．１８～１．６３。该文对色谱拆分机理及色谱分离条件进行了较详细的讨论。     

苦丁茶冬青挥发油成分的GC-MS分析

采用乙醚超声萃取-水蒸气蒸馏方法提取苦丁茶冬青的挥发油，用气相色谱-质谱联用分析，鉴定了挥发油中的57个成分，其中主要成分是醇、醛、酮、醚、脂肪酸、脂肪酸酯及含氧萜类等化合物。     

Quench Dynamics of Bose–Einstein Condensates in Boxlike Traps

By quenching the interatomic interactions, we investigate the nonequilibrium dynamics of two-dimensional Bose–Einstein condensates in boxlike traps with power-law potential boundaries. We show that ring dark solitons can be excited during the quench dynamics for both concave and convex potentials. The quench’s modulation strength and the steepness of the boundary are two major factors influencing the system’s evolution. In terms of the number of ring dark solitons excited in the condensate, five...     

DM-UKF混沌拟合破译混沌直接序列扩频通信

针对已有混沌直接序列扩频通信系统的破译算法在低扩频因子和较大多径衰落下无法有效破译信息码的问题,提出了一种基于双模型无迹卡尔曼滤波混沌拟合的破译算法.所提算法联合多模型滤波原理,利用信息符号为有限集的特点,针对其不同取值分别建立对应的滤波模型.各模型下滤波器并行工作,利用广义同步系统同时拟合原混沌系统并估计混沌直扩信号,通过估计误差确定最佳匹配滤波模型,从而得到信息符号的估计.进一步通过引入误差控制因子,增大了不同模型下估计误差的距离,不仅有利于信息符号判定,并且减小了噪声和多径衰落对破译结果的影响.理论推导和仿真结果均证明提出的算法优于已有破译算法.     

人卵透明带3基因片断hZ3.3的克隆及其在毕赤酵母中的表达

为了探讨透明带与精子的作用机制，人卵透明带3(human Zona Pellucida 3，hZP3)第19l位氨基酸到319位氨基酸之间的cDNA序列通过PCR方法扩增后，克隆到表达载体pPICZαA上，构建成重组质粒pPICZαA-hZ3．3。该质粒经SacⅠ线性化后电打孔转入Pichia pastoris酵母X-33中，用YPDS Zeocin^ 筛选高拷贝转化子，并用PCR分析鉴定目的基因片断与酵母基因组的整合，阳性转化子用0．5％甲醇诱导，表达目的蛋白。经SDS-PAGE凝胶电泳和Western-blot鉴定分析，结果表明目的基因成功表达，表达产物大小约为37kD。     

分歧点的多项式算子

针对在分歧点的计算过程中如何选择合适的扩展系统这一问题,本文通过研究折叠点,音叉式分歧点的多项式算子,利用逐项求导的方式,比较了它们的多项式算子,从而得出一个判断高阶折叠点和音叉点的统一的多项式算子,为解决分歧点计算过程中选择扩展系统的困难创造了条件.     

一步热聚合法制备Cu2O/CuO-g-C3N4吸附剂及其对甲基橙吸附的性能

用一步热聚合法制备了一种铜改性的石墨氮化碳吸附剂,并研究了其对甲基橙的吸附性能。以氧化亚铜、双氰胺为前驱体,以氯化胺作为气体模板,在高温下引发聚合获得了铜改性的石墨氮化碳吸附剂(Cu₂O/CuO-g-C₃N₄)。采用扫描电子显微镜(SEM)、X射线衍射(XRD)、X射线光电子能谱(XPS)及全自动比表面及孔隙度分析(BET)等对所制备吸附剂的组成和结构进行了表征,结果表明,该吸附剂由Cu、C、N和O共4种元素组成具有介孔结构的层状材料。引入铜氧化物以后,有效地扩展了g-C₃N₄的π共轭体系,有利于通过π-π作用吸附带有苯环结构的染料;Cu₂O/CuO-g-C₃N₄吸附剂具有多种孔径的介孔结构增大了其比表面积,为染料的吸附提供了足够的活性位点。通过优化吸附剂的制备条件、投加量、染料浓度、吸附时间、搅拌转速和pH等参数后,获得在最优条件下对甲基橙溶液的吸附率仅需25 min即可达到96.11%。进一步地,在常温常压下...     

LD Side-Pumped Passive Mode-Locked TEM_00 Nd:YAG Laser Based on SESAM

We report an LD side-pumped continuous-wave passive mode-locked Nd：YAG laser with a Z-type folded cavity based on a semiconductor saturable absorber mirror （SESAM）. The average output power 2.95 W of mode-locked laser with electro-optical conversion efficiency of 1.3% and high beam quality （Mx2=1.25 and My2=1.22） is achieved. The repetition rate of mode-locked pulse of 88 MHz with pulse energy of 34 nJ is obtained.