识别过渡金属离子的1,8-萘二甲酰亚胺多胺衍生物荧光传感器的研究

设计合成了用以检测过渡金属离子的荧光化学敏感器体系,它们是由1,8-萘二酰亚胺为荧光团,多胺衍生物为金属离子受体组成．在室温下对其光物理性质的研究中发现,在没有加入过渡金属离子时,由于体系内存在有效的光诱导电子转移过程使得荧光团的荧光被淬灭．加入过渡金属离子后,金属离子受体中的氮原子和过渡金属离子之间的配位作用阻断了光诱导电子转移过程,体系的荧光增强．不同的金属离子受体表现出了和过渡金属离子不同的配位识别能力,并且通过荧光的变化传递出受体-金属离子作用的信息．     

Structural and thermodynamic properties of AlB2 compound

We employ a first-principles plane wave method with the relativistic analytic pseudopotential of Hartwigsen, Goedecker and Hutter (HGH) scheme in the frame of DFT to calculate the equilibrium lattice parameters and the thermodynamic properties of AlB₂ compound with hcp structure. The obtained lattice parameters are in good agreement with the available experimental data and those calculated by others. Through the quasi-harmonic Debye model, obtained successfully are the dependences of the normalized lattice parameters a/a₀ and c/c₀ on pressure P, the normalized primitive cell volume V/V₀ on pressure P, the variation of the thermal expansion α with pressure P and temperature T, as well as the Debye temperature \Theta_D and the heat capacity C_V on pressure P and temperature T.     

The polar ionosphere at Zhongshan station on May 11, 1999, the day the solar wind almost disappeared

The solar wind almost disappeared on May 11, 1999: the solar wind plasma density and dynamic pressure were less than 1cm⁻³ and 0.1 nPa respectively, while the interplanetary magnetic field was northward. The polar ionospheric data observed by the multi-instruments at Zhongshan Station in Antarctica on such special event day was compared with those of the control day (May 14). It was shown that geomagnetic activity was very quiet on May 11 at Zhongshan. The magnetic pulsation, which usually occurred at about magnetic noon, did not appear. The ionosphere was steady and stratified, and the F₂ layer spread very little. The critical frequency of day-side F₂ layer, f₀F₂, was larger than that of control day, and the peak of f₀F₂ appeared 2 hours earlier. The ionospheric drift velocity was less than usual. There were intensive auroral E_s appearing at magnetic noon. All this indicates that the polar ionosphere was extremely quiet and geomagnetic field was much more dipolar on May 11. There were some signatures of auroral substorm before midnight, such as the negative deviation of the geomagnetic H component, accompanied with auroral E_s and weak Pc3 pulsation.

     

Analysis of Aperture Field of Circular Groove Guide Horn Antenna by Using FD-TD Method

This paper presents an instance of using FD-TD method to analyze the aperture field of circular groove guide horn antenna. This process is one part of a hybrid method to solve the radiation field of aperture antenna. To verify the calculated aperture field the radiation pattern is computed from it and compared with the measured one. Good agreement is reached.     

一类函数方程的稳定性及微商配置解

本文对一类重要的函数方程建立解稳定性定理,提出微商配置解,证明了收敛性.     

二维位置灵敏探测器输出图像畸变的修正

高分辨(e,2e)谱仪采用二维位置灵敏探测器同时对能量和角度进行多道测量.二维位置灵敏探测器由级联使用的微通道板和电阻阳极板组成,由于电阻阳极板的边缘效应和制造工艺的缺陷,测量得到的位置图像与实际图像总会有一定的形变,存在一定的非线性.本文针对高分辨(e,2e)谱仪二维位置灵敏探测器输出图像的“桶形”畸变及位置非线性,采用一种简易的冷刻法(用脉冲信号来模拟真实电子束团),检验了二维位置灵敏探测器的Gear型电阻阳极板的线性好坏,并用分割成小三角形的方法找出测量得到的畸变图像与原始真实图像的映射关系,再用此关系对其它测量得到的畸变图像进行修正,并对修正的结果进行了评估.通过修正,由“桶形”畸变所造成的图像扭曲得到明显改善.修正后的x方向非线性由修正前的2.1%变为0.59%.这种检验和修正方法对其它领域类似探测器输出图像的修正也有一定的指导意义.     

磁控溅射ZnO薄膜生长的等离子体发射光谱研究

通过反应磁控溅射过程中的等离子体发射光谱，研究了制备ZnO薄膜的沉积温度、氧气流量比例R=O₂/(O₂+Ar)对Zn和O原子发射光谱的影响，并结合ZnO薄膜的结构和物理性能，探讨了沉积温度在ZnO薄膜生长中的作用.研究结果显示：当R≥0.75%时， Zn的溅射产额随R的增加基本呈线性下降规律.当R介于10%—50%时，氧含量的变化相对平缓，有利于ZnO薄膜生长的稳定性控制.Zn原子发射光谱强度随沉积温度的变化可以分为三个阶段.当沉积温度低于250℃时，发射光谱强 关键词： ZnO 薄膜生长 反应磁控溅射 等离子体发射光谱     

〈111〉晶向冲击加载下单晶铜中纳米孔洞增长的早期动力学行为

利用分子动力学方法模拟计算了单晶铜中纳米孔洞在沿〈111〉晶向冲击加载下增长的早期过程.测量发现不同加载强度下等效孔洞半径随时间近似成线性变化.观测到单孔洞增长的两种位错生长机理：加载强度较低时，只在沿着冲击加载方向的孔洞顶点附近区域有位错的成核和运动；而随着加载强度超过一定阈值，在沿冲击加载和其垂直方向的孔洞顶点区域都观察到位错的成核和运动.在前一种机理作用下，孔洞只沿加载方向增长；在后一种机理作用下，孔洞同时沿加载和垂直于加载方向增长.分析孔洞表面原子的位移历史，发现沿加载及与其垂直方向的孔洞顶点沿径向的速度基本恒定，由此提出了一个孔洞生长模型，可以解释孔洞增长的线性生长规律. 关键词： 纳米孔洞 分子动力学 冲击加载 位错     

工科物理实验课程改革与实践

针对21世纪实验教学的要求,介绍了开展工科物理实验教学体系与教学内容改革的经验。     

New ligands for the Fe(III)‐mediated reverse atom transfer radical polymerization of methyl methacrylate

A series of (di)picolinic acids and their derivates are investigated as novel complexing tridentate or bidentate ligands in the iron‐mediated reverse atom transfer radical polymerization of methyl methacrylate in N,N‐dimethylformamide at 100 °C with 2,2′‐azobisisobutyrontrile as an initiator. The polymerization rates and polydispersity indices (1.32–1.8) of the resulting polymers are dependent on the structures of the ligands employed. Different iron complexes may be involved in iron‐mediated reverse atom transfer radical polymerization, depending on the type of acid used. ¹H NMR spectroscopy has been used to study the structure of the resulting polymers. Chain‐extension reactions have been performed to further confirm the living nature of this catalytic system. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 44: 2912–2921, 2006