A fluorescein-based probe with high selectivity to cysteine over homocysteine and glutathione

A fluorescent probe based on fluorescein displays excellent selectivity and sensitivity for cysteine and its application for bio-imaging is described.     

多孔有限大弹性薄板弯曲应力集中问题

应用弹性力学的复变函数理论,采用多保角变换的方法,推出了含有任意多孔有限大弹性薄板弯曲的多复变量应力函数的表达式.在内边界上进行复Fourier级数展开,在外边界采用配点法来确定应力函数的未知系数,从而计算有限大弹性薄板的应力场.本文以外边界为矩形,内边界为任意多椭圆孔的有限薄板为例,编制了相应的计算程序,进行了算例分析.结果表明本方法对处理多孔有限大弹性平面问题是简单且行之有效的.     

ADSORPTION BEHAVIOR OF AMINO ACIDS ON COPPER SURFACES

The major results of a series of our recent investigations on the adsorption of eight amino acids on Cu(001) and (111) surfaces are reviewed in the present paper. In all studied cases the molecules adsorb onto the surface in their anionic form. With the increase of the coverage three different 2D phases of the adsorbates, that is, the 2D lattice gas, intermediate, and solid phases, appear sequentially, although for few systems one or two of them do not appear. In both the 2D lattice gas and intermediate phases the molecules "stand" with their two oxygen "feet" on the surface and the intermolecular interactions are repulsive, although in the former they can diffuse frequently whereas in the latter they are discommensurate in one direction with the substrate. In the solid phase the molecules "lie" down on the surface to form commensurate superstructures. Adsorption of amino acids may often induce step faceting as well as bunching to form facets. Adsorption of L-lysine on Cu(001) may cause steps bunching to form facets with all the same chirality. Our preliminary results show that it is possible to manipulate individual molecules with the STM tip even at room temperature. These results may have applications in nano-materials, nano-technology, and very likely also in chiral separations or enantioselective heterogeneous catalysis.     

弹性波与单侧界面裂纹相互作用问题的边界元法

借助边界元法设计了一种迭代修正方法来求解单侧界面裂纹模型与弹性波的相互作用问题,作为对算法的检验,用这种方法我们具体地分析了平面简谐弹性波对一个单侧界面裂纹的入射,给出了裂纹面的接触形态及应力场.     

油田稳产措施规划数学模型

措施规划是油田开发领域的一项极为重要的工作,它对于延长油田稳产年限,合理地安排稳产措施是十分必要的.本文对措施规划的几类数学模型进行了分析,提出了对不确定性因素的处理--随机规划的建立与求解方法.     

苯系物扩散管气体标准物质的研制

按照ISO 6145—2003、ISO 6144—1998标准,研制了新型气体标准物质动态配气装置,实现了微机对动态配气装置主要参数数据的实时监控。用该装置研制了氮中微量苯系物扩散管气体标准物质,量值的相对扩展不确定度为2％-3％,并与静态容量法配气进行了比较。     

基于Flash cs3 AS的大学物理CAI课件开发

本文阐述了Flash cs3 AcdonScript课件的优势及如何利用Flashcs3中具有的强大编程功能的AetionScript脚本语言制作大学物理CAI课件。     

利用傅立叶变换红外光谱法检测一氧化氮纯气中的氧化亚氮杂质

利用傅立叶变换红外光谱法对一氧化氮纯气中的氧化亚氮进行了定性和定量分析。实验结果显示,在恒定条件下进样,分辨率为0.5cm^-1,扫描512次,选择2270～2130cm^-1范围内的特征吸收进行定量分析时可以得到良好的分析结果。利用双点法对氧化亚氮杂质进行定量计算;并对分析结果进行了严格的不确定度评定,为一氧化氮纯气中氧化亚氮的检测提供了一个全新的方法。     

Oxidative Desulfurization Activity of NIT Nitroxide Radical Modified Metallophthalocyanine

In the present study, metallophthalocyanines were modified with NIT nitroxide radicals through chemical bonds to prepare a series of metallophthalocyanines–NIT catalysts (MPcTcCl₈-NIT, M=Mn²⁺, Fe²⁺, Co²⁺, Ni²⁺, Cu²⁺ and Zn²⁺) applied for oxidative desulfurization of thiophene (T) in model fuel. The MPcTcCl₈-NIT catalysts were characterized by FTIR, UV-Vis, ESR, and XPS spectra. The oxidative desulfurization activity of MPcTcCl₈-NIT catalysts was studied in a biomimetic catalytic system using molecular O₂ as the oxidant. The MPcTcCl₈-NIT catalysts exhibited high catalytic activities for the oxidation of thiophene in model fuel. The desulfurization rate of ZnPcTcCl₈-NIT for thiophene reached to 99.61%, which was 20.53% higher than that of pure ZnPcTcCl₈ (79.08%) under room temperature and natural light. The results demonstrated that MPcTcCl₈-NIT catalysts could achieve more effective desulfurization rate under milder conditions than that of the metallophthalocyanines. The NIT nitroxide radicals also could improve the catalytic activity of metallophthalocyanine based on the synergistic oxidation effect. The stability experiments for ZnPcTcCl₈-NIT showed that the catalyst still had a high desulfurization rate of 92.37% after five times recycling. All these findings indicate that the application of MPcTcCl₈-NIT catalysts provides a potential new way for the desulfurization performance of thiophene in fuel.     

结构力学教学核心概念的精细研究——以力法为例

平衡、约束、柔度等是力学理论的基本核心概念,本文旨在建立一种更为强调核心概念精细分析与理解的教学理念,而不仅仅重视求解题目.分析了两个教学案例：一是对称结构的柔度矩阵可逆性证明,利用实功恒为正值这一原理推导出柔度矩阵行列式恒不为零的结论;二是力法求解桁架结构时切断和拆除同一杆件,典型方程及柔度系数发生变化,从而显示出基本方程的物理意义、广义位移等概念,这种精细研究对深入理解算法机理具有重要作用.探讨了力学概念精细研究对于教学的重要性.