荧光法研究对羧基苯偶氮基杯[8]芳烃与诺氟沙星的作用

合成了一种超分子探针对羧基苯偶氮基杯[8]芳烃(简称CPAC).利用荧光光谱法研究了溶液状态下该探针与诺氟沙星(简称NFLX)的相互作用.实验表明,两者之间存在较强烈的相互作用,CPAC与NFLX形成外式包结物,静态猝灭NFLX的荧光,CPAC的杯腔体与NFLX的喹啉环间的疏水作用是主要作用方式.测定了该反应的结合常数(K=6.38×105 L·mol-1)和结合比(n=1).实验发现,小牛胸腺DNA能夺取CPAC-NFLX体系中的CPAC,使NFLX游离,说明超分子化合物CPAC可用于诺氟沙星药物的储存和定点释控.     

Aggregation Behaviour of Cationic Diblock Copolymer （MTAC）10（BA）16： MesoDyn Simulation Study

The aggregation behaviour of an amphiphilic cationic block copolymer （MTAC）10（BA）16 in aqueous solution is investigated by MesoDyn simulation. Simulation results show that （MTAC）10 （BA）16 can form spherical, irregular and network aggregates with the increasing volume fraction. The time evolution of order parameter shows that the process of aggregate formation can be divided into diffusion control stage and hydrophobic interaction control stage, while the time evolution of energy indicates that the aggregate formation is driven by enthalpy but not entropy. The order parameter of the hydrophobic blocks BA increases with the increasing （MTAC）10（BA）16 concentration, while the time needed for system balance has the contrary trend.     

Experimental Study on Electrostatic with Two Guiding of Supersonic D20 Molecular Beam Charged Wires

We demonstrate the guiding of a supersonic heavy-water （D2O） molecular beam using a hollow electrostatic field generated by the combination of two parallel charged-wires and two grounded metal-plates, and report some new and preliminary experimental results. In the experiment, we detect the guiding signals by using the method of time-of-flight mass spectrum and study the dependence of the relative transmission of the beam guide on the guiding voltage. Our study shows that the relative transmission of the beam guide is increased linearly with increasing guiding voltage Vguid, and the number of the guided D20 molecules is at least increased by 89.4% when the guiding voltage is ＋20.0k V. Finally, some potential applications of our guiding scheme in the molecule optics are briefly discussed.     

Elastic Modulus and Hardness of Cr-Nb Nano-Multilayers

Cr-Nb nano-multilayered films with various modulation wavelengths A are prepared by e-gun evaporation and their mechanical properties are investigated. Cr and Nb both have bcc structures with large differences in lattice constants and Young＇s modulus, which are supposed to favour modulus enhancement. Nevertheless, nano-indention measurements show no enhancement for the modulus and a slight decrease for the hardness with decreasing A down to 5 nm. This is mainly due to counter-contribution to modulus from adjacent layers subjected to reverse strains, in agreement with recent theoretical study, while the decrease of hardness arises from grain boundary sliding. Interestingly, at A = 3 nm, the hardness of the film has an increase of 44% relative to the value of a rule of mixture, owing to the emergence of a new phase for reconciling the structure difference at the interfaces.     

Theoretical Investigation of Femtosecond-Resolved Photoelectron Spectrum of Na2 Molecules

Effect of laser fields on Na2 interaction potentials is studied by calculating the time-resolved photoelectron spectrum （TRPES） with the time-dependent wave-packet method. It is shown that the photoelectron spectrum at different delay times reflects the population in different electronic states. We inspect the periodicity of vibrational motion in neutral states, and map the vibrational wave-packet propagation in corresponding internuclear coordinate.     

4 ,4′-二巯基二苯醚分子的电子输运性质研究

利用从头算方法和弹性散射格林函数理论,研究了4 ,4′-二巯基二苯醚分子的电输运性质.计算表明,当外加偏压少于0 .9 V时,该分子器件不导电.当外加偏压进一步增加时,该分子器件的电导呈现出平台特征.由于中间氧原子的存在,相对于4 ,4′-二巯基联苯分子来说,该分子的导电特性较差.     

阿伏伽德罗（Avogadro，Amedeo,1776-1856）意大利物理学家（Physicist，Italy）

阿伏伽德罗出生于都灵的一个贵族家庭，毕生致力于原子论的研究。当时由于道尔顿和盖-吕萨克研的工作，近代原子论处于开创时期，阿伏伽德罗从盖-吕萨克定律得到启发，于1811年提出了一个对近代科学有深远影响的假说：在相同的温度和相同的压力条件下，相同体积中的任何气体总含有相同的分子个数。但他的这个假说却长期不为科学界所认同，主要原因是当时科学界还不能区别分子和原子，同时由于有些分子发生了离解，出现了一些阿伏伽德罗假说难以解释的情况。     

利用可调谐半导体激光光谱技术对含尘气体中NH3的测量

利用可调谐半导体激光吸收光谱技术(TDLAS)并结合波长调制,在近红外波段1531.7nm处对常温常压下的NH3进行浓度测量.在10 m的长程吸收池内得到了25×10-6的浓度信号,并且在25×10-5-400×10-6浓度范围内二次谐波信号与浓度具有良好的线性关系.讨论了粉尘颗粒对于二次谐波信号的干扰,并提出了利用激光强度线性拟合解决颗粒对气体测量干扰的方法.     

蒙特卡罗模拟四极阱中原子的参变激发

在中性原子的磁囚禁实验中,磁阱线圈的电流噪声会激发磁阱中的原子运动,势必对原子团的温度和寿命产生不可忽视的影响。对于非简谐阱,这种激发具有能量选择特性,它又取决于电流噪声的频谱分布。选择了实验中常用的四极阱为研究对象,用直接模拟蒙特卡罗方法来模拟四极阱中原子运动的参变激发现象,得到了原子温度与原子数损失随激发频率的变化关系,并进一步计算了两个共振峰处原子温度随调制时间和调制深度的变化曲线。此外,还研究了弹性碰撞速率对参变激发过程中原子温度上升的影响。这些结果对四极阱参变激发的实验有较好的参考价值。     

对DNA堆垛力的直接测试

DNA分子是一个科学家们非常关注的重要大分子。常见的双绞合DNA分子，它的内部具有两种特征性的作用力：一个是沿着双螺旋长度方向在碱基间的堆垛力；另一个是在反向碱基之间的配对力，配对力的大小会影响螺旋线的螺圈。从1990年起就一直对双绞合DNA分子的弹性数据进行测定，但测定出的数据中却很难将堆垛力与配对力区分开。