Delocalization of quasiparticles in quasi-two-dimensional disordered superconductors with s-wave pairing

We investigate localization behavior of quasiparticles in disordered multi-plane superconductors with s-wave pairing. By introducing disorder with random site energies, the spatial fluctuations of Bogoliubov-de Gennes pairing potential are self-consistently determined. The size dependence of rescaled localization length for a long bar is calculated by using the transfer-matrix method. From the finite-size scaling analysis we show that there exists a critical point of the disorder strength W_c which separates the extended and localized quasiparticle states in such quasi-two-dimensional systems. The associated critical behavior is studied and the relationship of the results to the number of planes is discussed.     

Synthesis and characterization of a tetrazolate-bridged coordination framework encapsulating D2h-symmetric cyclic (H2O)4 cluster arrays

Reaction of 5,5'-(1,4-phenylene)bis(1H-tetrazole), which was prepared in two steps, with cadmium nitrate in DMF produced a three-dimensional framework with one-dimensional channels (35% void volume), in which unprecedented hydrogen-bond-supported D(2)(h)() tetrameric cyclic water clusters ranked.     

转基因棉花残体土壤降解特征的红外光谱研究

采用重铬酸钾容量法和红外光谱(FTIR)法分析了转基因抗虫棉花残体降解后的土壤腐殖质组分富里酸(FA)、胡敏酸(HA)和胡敏素(HM)的含量和结构特征.结果表明,棉花残体的降解使土壤各腐殖质组分含量增加,胡敏素的相对含量增加最大,胡敏酸次之,富里酸最小.与相应非转基因对照相比,转Bt基因棉花残体处理土壤各腐殖质组分含量...     

AlN纳米线宏观阵列的制备

借助二次模板法成功的合成了AlN纳米线宏观阵列,并进行了表征.主要研究CVD法制备有一定取向,直径均匀的AlN纳米线宏观阵列的过程.通过气相沉积法和利用PS球自组装模板制备了金属纳米颗粒模板;再以模板上的金属纳米颗粒作为催化剂,利用化学气相沉积在模板上合成AlN纳米线宏观阵列.借助SEM,TEM观察所得样品,AlN纳米线阵列面积约为0.3 mm×0.2 mm,直径和长度分布均匀,平均直径约为41 nm,平均长度为1.8 μm左右,分散密度和覆盖率大的六角结构AlN纳米线宏观阵列.得到了可控制备AlN纳米线 关键词： AlN纳米线阵列 模板法 CVD法 SEM     

基于物相与成分分析的中药炉甘石基源研究

通过对56批炉甘石样品的物相与成分分析,为增补水锌矿作为炉甘石基源矿物提供了依据。电子探针微区分析表明:炉甘石是一种复杂的矿物集合体,由水锌矿、菱锌矿、异极矿、白云石、方解石等多种散在共生的微小矿物颗粒共同构成;红外光谱结构分析的结果显示:市售炉甘石的主流矿物为水锌矿。炉甘石药用均为煅烧后入药,作为炉甘石基源的水锌矿与菱锌矿,经炮制后其化学成分均转变为氧化锌,两者化学本质相同。故在保证原矿品质的前提下,两者可共同作为炉甘石的基源矿物。     

基于多级组合棱镜提高激光中心波长检测精度的研究

为了在保证抗干扰能力不下降的条件下提高对激光中心波长的检测精度,设计了多级组合棱镜系统,并提出了多级组合棱镜的干涉条纹拼接处理方法及相位耦合的计算公式.通过计算多级组合棱镜的干涉图强度、光程差函数及光谱分辨率,分析了采用三块子棱镜的组合结构的光谱获取,给出了用于分段干涉条纹拼接的处理方法及步骤,最终光谱分辨率可达2.8...     

利用透射电镜衬度像变化判定位错环类型及注氢纯铁中形成的位错环分析

本文分两部分,第一部分研究了利用透射电镜衬度像变化判定材料中位错环类型的方法,即采用所谓inside-outside方法来判断位错环为空位型位错环或间隙型位错环. 第二部分讨论了加速器注氢纯铁在673—773 K时效后形成的位错环的类型. 关键词： 透射电镜 空位型位错环 间隙型位错环 氢     

自然电位测井的数学模型

自然电位测井是石油开发中一种常用而重要的测井方法。自然电位函数的数学模型可归结为具有间断交界面条件的椭圆型等位面边值问题,在交界面交汇点处,自然电位的跳跃通常不满足相容性条件,此时,这个边值问题不存在分块H1*解,不能使用有限元素法直接求解。本文介绍这一测井方法的数学模型及数值求解方法。     

Insights into the nature of X(3872) through B meson decays

We study the \begin{document}$ B_{c,u,d}\to X(3872)P $\end{document} decays in the perturbative QCD (PQCD) approach, involving the puzzling resonance \begin{document}$ X(3872) $\end{document}, where P represents a light pseudoscalar meson (K or π). Assuming \begin{document}$ X(3872) $\end{document} to be a \begin{document}$ 1^{++} $\end{document} charmonium state, we obtain the following results. (a) The branching ratios of the \begin{document}$ B^+_c\to X(3872)\pi^+ $\end{document} and \begin{document}$ B^+_c\to X(3872) K^+ $\end{document} decays are consistent with the results predicted by the covariant light-front approach within errors; however, they are larger than those given by the generalized factorization approach. (b) The branching ratio of the \begin{document}$ B^+\to X(3872)K^+ $\end{document} decay is predicted as \begin{document}$ (3.8^{+1.1}_{-1.0})\times10^{-4} $\end{document}, which is smaller than the previous PQCD calculation result but still slightly larger than the upper limits set by Belle and BaBar. Hence, we suggest that the\begin{document}$ B^{0,+}\to X(3872)K^{0,+} $\end{document} decays should be precisely measured by the LHCb and Belle II experiments to help probe the inner structure of \begin{document}$ X(3872) $\end{document}. (c) Compared with the \begin{document}$ B_{u,d}\to X(3872)K $\end{document}decays, the \begin{document}$ B_{u,d}\to X(3872)\pi $\end{document} decays have significantly smaller branching ratios, which drop to values as low as \begin{document}$ 10^{-6} $\end{document}. (d) The direct CP violations of these considered decays are small (\begin{document}$ 10^{-3}\sim 10^{-2} $\end{document}) because the penguin contributions are loop suppressed compared to the tree contributions. The mixing-induced CP violation of the \begin{document}$ B\to X(3872)K^0_S $\end{document} decay is highly consistent with the current world average value \begin{document}$ \sin2\beta=(69.9\pm1.7)$\end{document}%. Experimentally testing the results for the branching ratios and CP violations, including the implicit \begin{document}$S U(3)$\end{document} and isospin symmetries of these decays, helps probe the nature of \begin{document}$ X(3872) $\end{document}.     

离子束辅助沉积对类金刚石膜结构影响的计算机模拟

采用分子动力学(MD)模拟研究了离子束辅助沉积(1BAD)生长类金刚石(DLC)膜的物理过程.分 别选C₂分子和Ar离子作为沉积源和辅助沉积粒子.改变Ar的入射能量和到达比(A r／C)，研 究了它对DLC膜结构的影响.重点讨论了Ar辅助沉积引起表面原子的瞬间活性变化对薄膜结构 产生的影响.分析表明，由于Ar离子的轰击引起的能量和动量的传递，大大地增强了C原子在 表面的反冲动能及迁移概率，增加了合成薄膜的SP³键含量.研究结果和实验 观察一致，并从合成机理上给出了一些定量解释. 关键词： 类金刚石膜 离子束辅助沉积 分子动力学模拟