Persistent currents in three-dimensional shell-doped nanorings

The persistent current in three-dimensional (P× N²) nanorings as a function of the unit cell number (P), the channel number (M = N²), surface disorder (ξ ), and temperature (T) is theoretically investigated in terms of rotational symmetry. On the whole, the typical current increases linearly with \sqrt M but decreases exponentially with P, while wide fluctuations exist therein. In the presence of surface disorder, the persistent current decreases with ξ in the regime of weak disorder but increases in the regime of strong disorder. In addition, it is found that the persistent current in perfect rings decreases exponentially with temperature even at T < T^*     

高效液相色谱-蒸发光散射检测法测定合成产物中的果糖棕榈酸酯

建立了反相高效液相色谱-蒸发光散射检测（HPLC-ELSD）测定合成产物中的果糖棕榈酸单酯和果糖棕榈酸双酯的方法。HPLC-ELSD条件为：反相Prevail C18色谱柱,柱温为30 ℃,流动相为乙酸乙酯-甲醇-水（体积比为59.4∶30∶10.6）,流速为1 mL/min,ELSD漂移管温度为73.8 ℃,载气流速为2 L/min。在该色谱条件下,果糖棕榈酸单酯及果糖棕榈酸双酯在进样量为1～15 μg时,与其峰面积的线性关系良好,相关系数r2均大于0.9996。     

Zygmund 空间到 Bloch 空间上径向导数算子与积分型算子的乘积

设$H(\mathbb{B})$为单位球上全纯函数类,研究了单位球上 Zygmund 空间到 Bloch 空间上径向导数算子$\Re$与积分型算子$I_\varphi^g$乘积的有界性和紧性, 这里 $$ I_\varphi^g f(z)=\int_0^1 \Re f(\varphi(tz))g(tz)\frac{{\rm d}t}{t},\quad z\in\mathbb{B}, $$ 其中$g\in H(\mathbb{B}),\ g(0)=0$, $\varphi$ 是$\mathbb{B}$上全纯自映射.     

基于特定网格计算环境的信任管理模型

基于信任管理引擎的信任管理模型,提出了信任管理是信任意向的获取、评估和实施的新定义,并应用于已有的一个新型网格安伞信任体系架构(NGST)中,将网格环境划分为多个自治域,每个自治域由一个信任代理处理本域所有信任关系的问题.在此环境下建立了域内信任管理模型,给出了安全性的形式分析与证明,利用凭证访问策略来保护协商双方的安全凭证中的敏感信息.结果表明,本文提出的信任管理模型是安全的,具备很好的自治性,并且能有效地将不良行为较多实体逐出自治域.     

话说中考“陷阱”题

中考中,根据学生认识上的片面性而设置的"陷阱"题常使一些考生深陷其中,出错率很高.如何透视考题"陷阱"?笔者在此介绍一些常见的"陷阱"设置方法,以期引起同学们重视.     

An encryption scheme based on phase-shifting digital holography and amplitude-phase disturbance

In this paper, we propose an encryption scheme based on phase-shifting digital interferometry. According to the original system framework, we add a random amplitude mask and replace the Fourier transform by the Fresnel transform.We develop a mathematical model and give a discrete formula based on the scheme, which makes it easy to implement the scheme in computer programming. The experimental results show that the improved system has a better performance in security than the original encryption method. Moreover, it demonstrates a good capability of anti-noise and anti-shear robustness.     

一个序号数列遍历性猜想的证明

1 引言--几个相关概念 由凸n(n≥3,n∈N)边形的边或对角线组成的n边封闭折线,称为n边星形.沿n边星形所在圈的某一方向(逆时针或顺时针)将它的顶点依次标号为1,2,…,bi,…,n,m+1,…,并约定bn+i与6i是同一顶点的标号.     

Resonance Transmission in Graphene-Nanoribbon-Based Quantum Dot and Superlattice

By using a decomposition elimination method for Green＇s function, the transport properties of Graphenenanoribbon-based quantum dot （QD） and/or QD superlattice are studied. It is shown that relatively small changes of both QD size and magnetic field intensity can induce strong variations in the electron transmission across the structure. For a QD device, electrons can be either totally reflected or totally transmitted through the QD region at some energies, and the quasibound peaks have been observed to have a small shift due to quasibound state energy varying. In the case of QD superlattice, the electrons within the miniband energy region can transmit through a device, similar to a QD device. Therefore, the transmission spectrum can be tailored to match with requirement by modulating the size of quantum dot and the number P of superlattice.     

一种耐高温聚苯并嗪的电化学合成

苯并噁嗪最先由 Holly和 Cope在 1 944年通过曼尼奇反应由苯酚、甲醛、胺合成而得 [1] .苯并嗪能够热聚合 .Ishida等 [2 ]在这方面做了大量工作 ,总结了热聚合苯并嗪的两种基本方法 .此外 ,某些苯并嗪还能象聚酚那样通过电化学方法沉积在金属表面形成聚合物来保护金属不受腐蚀[3] .但由于所得聚合物处于绝缘态 ,往往得不到自支撑的聚合物薄膜 .本文从乙腈 /氢氧化钠水溶液的混合溶液体系中成功地合成了一种新的自支撑的聚苯并嗪薄膜 ,其在空气中的热分解温度达 3 60℃ ,对酸、碱表现出很好的化学惰性 ,是一种很好的电极防腐材料 .…