Langevin Treatment of Atomic Coherence Effect on Hybrid Erbium doped Fiber Amplification

１　Ｉｎｔｒｏｄｕｃｔｉｏｎ　　Ｒｅｃｅｎｔｒｅｓｅａｒｃｈｏｎｔｈｅｅｆｆｅｃｔｓｏｆｏｐｔｉｃａｌｃｏｈｅｒｅｎｃｅｏｒｑｕａｎｔｕｍｉｎｔｅｒｆｅｒｅｎｃｅｈａｓａｄｖａｎｃｅｄｎｅｗｃｏｎｃｅｐｔｓｏｆｌａｓｅｒｗｉｔｈｏｕｔｉｎｖｅｒｓｉｏｎ［１,４］,ｅｌｅｃｔｒｏｍａｇｎｅｔｉｃａｌｌｙｉｎｄｕｃｅｄｔｒａｎｓｐａｒｅｎｃｙ［２］,ｅｎｈａｎｃｅｄｉｎｄｅｘｏｆｒｅｆｒａｃｔｉｏｎ［３］,ａｎｄｏｔｈｅｒｓ［５,６］．Ａｔｏｍｉｃｃｏｈｅｒｅｎｃｅａｎｄｌａｓｉｎｇｗｉｔｈｏｕｔ…     

碳化钨用作质子交换膜燃料电池催化剂载体的抗氧化性能

 采用还原碳化法制备了碳化钨样品,并用原位还原法担载Pt粒子得到Pt/WxCy催化剂. 利用计时电流技术对Pt/WxCy和常规Pt/C催化剂进行氧化处理,并用循环伏安法测试了氧化前后两种催化剂的电化学活性面积. 将两种催化剂制成单电池,对比研究了其氧化后的性能衰减. 结果表明, Pt/WxCy催化剂制成的单电池抗氧化能力显著高于普通Pt/C制成的单电池.     

剩余三阶色散对相位共轭偏振孤子的影响及其补偿

光学相位共轭中剩余三阶色散不利于共轭孤子的稳定传输,导致孤子脉冲具有更大的时间抖动.本文提出在传输线末采用具有正三阶色散的色散位移光纤补偿光学相位共轭中的剩余正三阶色散.数值结果证明了其可行性.同时也分析其补偿的物理机制.     

X射线衍射增强成像中的信息分离和信息处理

人们已经利用X射线的高穿透性,发展了较为成熟的X射线成像理论和技术. X射线成像已经广泛应用于众多领域.传统X射线成像受生物样品中组织间吸收系数差别较小和散射噪声较大两个因素的限制,不易利用这种方法获得生物组织的信息. 衍射增强成像方法不但能将有害的散射噪声滤除,而且能利用样品的折射信息, 是一种具有发展潜力的新成像方法. 本文利用衍射增强成像, 通过在摇摆曲线不同部位成像, 然后对信息处理, 得到了清晰的吸收像、消光(小角散射滤除)像、小角散射(角)宽度像和折射像,最后通过一定的算法将各种成分的像合成, 形成细节部位清晰的合成伪彩色像.     

温度变化对1.23 m望远镜光机系统的影响

为了实现1.23 m望远镜在环境温度从-35℃~+55 ℃变化范围内,光机系统的成像质量的指标要求,本文从原理上分析了温度变化对光机系统中光学元件面形准确度及相对位置关系的影响,推导出了主次镜间光学间隔变化与像面离焦量的比例关系.通过对1.23 m望远镜光学结构的像质分析,结合光机结构设计,搭建了适合环境温度变化的光机系统,从方案设计上满足了望远镜系统的成像要求.通过实际的成像实验,验证了温度变化导致的主次镜光学间隔变化对望远镜系统成像带来的离焦的影响,并给出了具体的温度补偿措施,即采取次镜调焦的方式,可满足具体观测实验的要求.同时,为今后1.23 m望远镜以及类似的大口径望远镜系统的实验和技术改造提出了切实可行的意见.     

Mechanisms Causing Ballistic Thermal Rectification

The mechanism causing the ballistic thermal rectification in the harmonic system is analytically studied. Using the conceptual model of a dephasing probe, we obtain that phase breaking is unnecessary to realize the ballistic thermal rectification. However, it can change the strength of rectification. Asymmetric phonon-phonon interac- tion inducing the energy exchange of the normal mode of vibration is necessary to realize the ballistic thermal rectification. Moreover, the quantum statistics of phonons in at least one thermal reservoir is crucial to guarantee the asymmetric phonon-phonon interaction.     

A universal projective synchronization of general autonomous chaotic system

This paper investigates the generalized projective synchronization in general autonomous chaotic system. A universal controller is designed and the effectiveness is verified via theoretical analysis and numerical simulations. The controller design is irrelevant to concrete system structure and initial values. It has strong robustness and broad application perspective.     

Mg/Ce-USY分子筛催化苯酚甲醇烷基化

采用Mg、Ce双金属对USY分子筛催化剂进行改性.通过XRD、SEM、N_2吸附-脱附、NH3-TPD、Py-FTIR和TG-DTA分析方法对催化剂进行了表征.结果表明,双金属改性并没有改变USY的孔道结构,活性组分均匀负载在USY分子筛表面;Mg的加入能够更好地促进Ce元素在USY表面的分散,改性金属元素之间的酸碱相互作用显著提高催化剂表面弱酸强度的L酸中心数量.将改性催化剂应用于苯酚甲醇烷基化反应,邻甲酚选择性达到68.7%,高于Ce-USY的42.4%.     

EFFICIENT NUMERICAL INTEGRATORS FOR HIGHLY OSCILLATORY DYNAMIC SYSTEMS BASED ON MODIFIED MAGNUS INTEGRATOR METHOD

Based on the Magnus integrator method established in linear dynamic systems, an efficiently improved modified Magnus integrator method was proposed for the second-order dynamic systems with time-dependent high frequencies. Firstly, the second-order dynamic system was reformulated as the first-order system and the frame of reference was transfered by introducing new variables so that highly oscillatory behaviour inherits from the entries in the meantime. Then the modified Magnus integrator method based on local linearization was appropriately designed for solving the above new form and some improved also were presented. Finally, numerical examples show that the proposed methods appear to be quite adequate for integration for highly oscillatory dynamic systems including Hamiltonian systems problem with long time and effectiveness     

蛋白质多态解折叠行为与稳定性Ⅱ:酶的多态解折叠行为

基于结构基元模型,进一步假设,由n个结构基元组成的蛋白酶,其活性中心由na(na?n)个结构基元组成,酶活性仅与组成活性中心的结构基元相关.由此,推导出适合于蛋白酶解折叠研究的变性曲线、解折叠结构基元平均自由能、物种分布等表达式.本文以盐酸胍诱导的卵清溶菌酶解折叠为例,通过荧光方法测定的溶菌酶解折叠曲线,得出卵清溶菌酶由2个结构基元组成,结构基元平均自由能?G0element(H2O)为48.47 kJ/mol.物种分布表明,酶活性随盐酸胍浓度的变化仅仅反映的是结构基元1(?-片结构域)的解折叠,而结构基元2(?-螺旋结构域)的解折叠反映在3.8~5.0 mol/L盐酸胍浓度范围内.结构基元模型既可描述蛋白酶多态解折叠的谱学行为,又可解释蛋白酶活性的两态性质.