头孢匹胺钠与牛血清白蛋白的相互作用机理及共存金属离子的影响

研究了不同温度下牛血清白蛋白(BSA)与头孢匹胺钠(CPMS)的相互作用及常见金属离子(Mg²⁺、Zn²⁺、Cu²⁺、Fe³⁺、Co²⁺、Ni²⁺)对BSA-CPMS体系的影响。结果表明:CPMS能使BSA的荧光发生猝灭,其过程为静态猝灭并伴有非辐射能量转移;CPMS通过静电引力与BSA结合,结合常数为10⁴数量级,结合位点数约为1;结合主要作用于BSA的亚结构ⅡA中,结合距离r≈2.60 nm。同步荧光光谱和圆二色谱(CD)均表明CPMS使BSA构象发生了变化。     

全光纤光子集成器件及系统

本文对全光纤光子集成器件与系统进行了较为全面地综述。结合我们的工作 ,对目前的研究热点 :光纤光栅、光纤激光器、光纤放大器、光纤光栅分插器与传感器等诸多光子器件以及由这些器件组成的波分复用通信系统进行了介绍和评述。一些新成果和新进展表明 ,这些光子器件与系统在当今和未来的光通信中将发挥重要作用。     

L波段MILO低真空下工作特性的粒子模拟与实验研究

 通过实验和粒子模拟相结合的方法对L波段MILO在低真空度下的工作特性进行了研究。实验和模拟中都观察到了低真空情况下MILO的功率增强和频率升高，在2 Pa内，粒子模拟中没有观察到脉冲缩短现象，实验上脉宽略有下降，但是辐射微波单脉冲能量增大，MILO工作性能在低真空下有一定提高。研究发现适量等离子体填充同样可以改善MILO工作性能。     

微柱高效液相色谱法测定烟草样品中铁钴镍铜锌锰

研究了用2(2喹啉偶氮)5二甲氨基酚(QADMAP)为柱前衍生试剂,以Waters XterraTMRP18(1.0mm×50mm,2.5μm)微柱为固定相,72%的甲醇(内含0.5%的乙酸)为流动相,高效液相色谱法分离,二极管矩阵检测器检测测定铁、钴、镍、铜、锌和锰的方法。根据信噪比(S/N=3)得各金属离子的检出限分别为:铁3μg·L-1、钴和铜4μg·L-1、镍2μg·L-1、锌5μg·L-1、锰8μg·L-1,方法用于烟草中痕量铁、钴、镍、铜、锌和锰的测定,相对标准偏差在1.6%～3.8%之间,回收率在93%～107%之间,结果满意。     

Spherical and Deformed Shell Closures in Superheavy nuclei

The structure of superheavy nuclei has been studied using the macroscopic-microscopic model. The macroscopic energy was calculated with the continuous medium model in which the energy is expressed as a function of nucleon densities. The deformations and structures of superheavy nuclei were systematically investigated. Calculations reproduce well the available data of experimental α-decay energies and half-lives. The investigation of single-particle levels shows that the shell structure is deformation and isospin dependent. Potential-energy-surface calculations display that superheavy nuclei have in general harder shapes than the nuclei of other mass regions.     

丝素蛋白膜在高电场下的介电性能

丝素蛋白的分子结构兼具软段和硬段,且其结构单元具有较大的偶极矩(3.5D),在介电储能领域可能具有应用潜力.本文表征了丝素蛋白薄膜的在高电场下的介电性能,并研究了丝素蛋白的分子结构与高电场下介电性能的关系.结果 显示,丝素蛋白的二级结构变化与其高场介电行为关系密切,β-折叠结构增加有利于提高击穿强度,降低介电损耗.通过...     

Synthesis of N-Squaramidoacids and Their Application in Asymmetric Borane Reduction of Prochiral Ketones

A series of novel N-squaramidoacid ligands were prepared conveniently. Without converting to corresponding amino alcohols, these ligands could be used in asymmetric borane reduction of prochiral aromatic ketones to give secondary alcohols in good to excellent enantiomeric excesses. The results showed that N-squaramidoacids are more efficient ligands than N-sulfonyl amino acids. N-Squaryl proline was proved to be an excellent ligand in this catalytic asymmetric process.     

核科学百年讲座第六讲核科学技术在医学中的应用

文章介绍了核医学的发展历史及其在医学中的重大应用，介绍了核医学诊断、治疗的原理、特点以及核医学的几个重要分支学科．通过介绍，展示了核科学技术在人类医疗事业中的重大作用．     

Synthesis and Crystal Structure of {Cu2(pdc)2(4,4′-bipy)(H2O)·(3H2O}2

The title compound {Cu2(pdc)2(4,4′-bipy)(H2O)(3H2O}2 1 (H2pdc = pyridine-2,6- dicarboxylic acid, also known as dipicolinic acid; 4,4′-bipy = 4,4′-bipyridine) has been synthesized by the hydrothermal reaction and its structure was determined by single-crystal X-ray diffraction. The crystal is of triclinic, space group Pī with a = 7.2278(3), b = 10.6259(4), c = 17.7614(6)A, α= 79.5990(10), β = 83.6300(10), γ = 71.8280(10)o, V = 1272.60(8)A3, C48H44Cu4N8O24, Mr = 1371.07, Z = 1, Dc = 1.789 g/cm3, μ = 1.747 mm-1, F(000) = 696, R = 0.0397 and wR = 0.1137 for 3938 observed reflections (I > 2σ(I)). There are two kinds of Cu coordination environments, and each central copper(II) atom is five-coordinated in a distorted square-based pyramidal coordination geo- metry. Four copper(II) atoms are linked by four pdc and two 4,4′-bipy ligands to form an annular rectangle structure. Extensive hydrogen-bonding interactions involving carboxylate O atoms as well as coordinated and free water molecules lead to the formation of a three-dimensional network struc- ture.     

基于合成孔径聚焦技术的混凝土断面二维成像方法研究

针对提高混凝土结构超声无损检测分辨率的需要,提出了两种处理方法。在对低频B扫描数据进行合成孔径聚焦处理时,由于低频探测信号时间宽度大,波包会被拉伸,发生波包变形现象,为此,引入波包分解技术来解决这个问题。波包分解技术实质是用一些模型参数去描述检测信号,可以避免对回波信号所有采样点进行处理,不仅解决了波包变形问题,而且可以简化计算。对于实验中商用超声传感器引起的余振问题,提出一种数字滤波的补偿方法,通过水浸方式采集数据建立传感器系统补偿模型,用于实际检测信号中振铃的抑制,可提高成像的时空分辨率。数值仿真和实验结果证明,采用这两种方法后内嵌目标定位理准确,成像分辨率明显提高。