Observation of contrast variations of a copper (Ⅱ) complex by scanning tunneling microscopy

This report presents experimental observations of dramatic variations in STM images of bis [1,3-DI(p-n-tetradecyloxyphenyl)propane-1,3-dionato]copper( Ⅱ） (abbreviated to C14O-Cu)physisorbed on HOPG as the bias voltage is changed .Several representative image patterns were obtained for the rich changes of the internal contrast of the molecule .Submolecular features of the molecular cores and the interdigitated alkyl parts are clearly visible.     

Study of β—amyloid adsorption and aggregation on graphite by STM and AFM

The scanning tunneling microscopy(STM) and the atomic force microscopy(AMF) have been applied to the direct study of the adsorption and aggregation of β-amyloid(1-42)(Aβ42)on the hydrophobic graphite surface.It was found that Aβ42 were preferentially adsorbed on graphite defects such as the edges.Aβ42 peptides self-assembled into intermediate protofibrils,which in turn self-associated to form fibrils.Usually,two or more fibrils intertwined to form the helical structure.These results will provide an important clue to studying the aggregation process of β-amyloid.     

NMR study on self-assembled cage complex of hexamethylenetetramine and cucurbit[n]urils

Self-assembled complexes between cage com-pounds cucurbit[n = 5—8]urils and hexamethylenetetramine were studied by using NMR techniques. Experimental results reveal that hexamethylenetetramine can lid cucurbit[5]uril to forming self-assembled capsules in which nothing is encap-sulated yet; the cavity of the cucurbit[7]uril can accommo-date a hexamethylenetetramine molecule to form a self- assembled host-guest inclusion. Moreover, both the cavity interaction of the cucurbit[7]uril with hexamethylenetetra-mine稨Cl and the portal interaction of the dipole carbonyl of the cucurbit[7]uril with hexamethylenetetramine稨Cl lead to form self-assembled capsules in which the hexamethylene-tetramine稨Cl are encapsulated in the hexamethylenetetra-mine稨Cl lidded cucurbit[7]uril. Although the structures of the portal and cavity to cucurbit[5]uril are similar, there is no obvious interaction between decamethylcucurbit[5]uril and hexamethylenetetramine, and also between cucurbit [6]uril or cucurbit[8]uril and hexamethylenetetramine.     

Measuring radial Young’s modulus of DNA by tapping mode AFM

Based on tapping mode AFM imaging, a method was demonstrated to evaluate compression elasticity of single double-stranded DNA （dsDNA） molecules in the force region. With images under ambient conditions, Young＇s moduli of dsDNA in compression were calculated. Results demonstrated that Young＇s moduli of dsDNA can be simply deduced according to the proposed model. The method can also be used to evaluate the compression elasticity of similar soft nanomaterials.     

超高时空分辨光谱学

结合作者工作介绍和总结了超高时间空间分辨光谱学及其在介观体系和纳米材料超快动力学研究中的应用. 首先简述了扫描近场光学显微镜工作原理; 然后介绍了结合近场显微镜和飞秒时间分辨光谱技术获得时空超高分辨光谱的方法; 对其中的一些具体科学问题进行了分析; 最后通过几个典型的例子说明了超高时空分辨光谱学的重要应用.     

柴油流动改进剂对柴油中蜡晶形态的影响

采用偏光显微镜研究了自行研制的AVM系列柴油流动改进剂对蜡晶形态的影响.结果表明,柴油流动性改进剂的加入,使柴油中的蜡晶变短变小,阻碍蜡晶相互连接搭桥成网.柴油流动性改进剂的加入量根据柴油组成不同,都应有一个最佳点.对于不同柴油,柴油流动性改进剂中各组成存在一个最佳配比,这一配比下的产物降滤效果最好,微观表现对蜡晶的改善也最明显.大量的数据表明,柴油的蜡晶变化图像与实测的数据相吻合.     

显微镜发展与物理学关系的研究

根据显微镜发展历程,列举了其中最具代表意义的三个阶段:光学显微镜,电子显微镜和扫描隧道显微镜。并指出每一个发展阶段都和物理学的发展密不可分。     

L-胱氨酸组装体的STM研究

利用隧道扫描显微镜在室温低真空条件下,在高定向裂解石墨表面对自组装L-胱氨酸及其脱水后状态进行探测.实验表明,吸附在HPOG表面的L-胱氨酸相对完全干燥的组装体表现出更加有序的吸附状态.通过比较含水和脱水样品的单体图形,分析了分子骨架以及内部二硫键的变化.疏水作用、针尖样品的作用以及分子间作用力是诱导样品有序排列的主要原因.高分辨的图形对于吸附在固体表面水溶生物样品的研究,获取分子内部信息很有意义.     

碱激发对粉煤灰活性的影响

研究了粉煤灰的物理化学特性,设计了四种方案对粉煤灰进行改性,旨在扩大粉煤灰的应用. 通过对比改性前后Na2SiO3-粉煤灰试块的强度,使粉煤灰在改性前后的反应速度通过试块的强度得以体现. 扫描电镜照片显示,在机械粉磨结合化学激发处理后,坚硬的外壳大部分被破坏. 27Al的核磁共振图谱显示宽峰变窄. 29Si的核磁共振谱表明,Q0消失,Q2增多,Q4减少. 说明加入强碱并同时机械粉磨可有效破坏粉煤灰的玻璃微珠外壳及硅铝网络结构,可增强粉煤灰的潜在活性.     

核磁共振中基于分子间多量子相干理论扩散行为的模拟

本文采用粒子随机行走模型结合分子间多量子相干理论模拟双组分核自旋体系溶液分子的表观扩散行为,将模拟得到溶液分子表观扩散率与溶液分子自扩散系数的关系,与理论预测结果进行比较,发现二者吻合得很好。