Probing the local structure and mechanical response of nanostructures using force modulation and nanofabrication

Nanostructures of self-assembled monolayers (SAMs) are designed and produced using coadsorption and nanografting techniques. Because the structures of these artificially engineered domains are predesigned and well-characterized, a systematic investigation is possible to study the mechanical responses to force modulation under atomic force microscope tips. Force modulation imaging reveals characteristic contrast sensitivity to changes in molecular-level packing, molecule chain lengths, domain boundaries, and surface chemical functionalities in SAMs. By means of actively tuning the driving frequency, the resonances at the tip-surface contact are selectively activated. Therefore, specific surface features, such as the edges of the domains and nanostructures or desired chemical functionalities, can be selectively enhanced in the amplitude images. These observations provide a new and active approach in materials characterization and the study of nanotribology using atomic force microscopy.     

无水醋酸镍与水杨醛肟固相配位反应的热化学研究

用新型的具有恒定温度环境的反应热量计，以６ｍｏｌ·ｄｍ－３ＨＣｌ溶液为量热溶剂，分别测定了ＨＳＡＯ，Ｎｉ（Ａｃ）２和Ｎｉ（ＳＡＯ）２，ＨＡｃ先后溶于该溶剂的溶解焓．设计了一个新的热化学循环，计算得到该配位反应的反应焓ΔｒＨ＝－８６．０７５ｋＪ·ｍｏｌ－１，并估算出了ΔｆＨ［Ｎｉ（ＳＡＯ）２，２９８Ｋ］＝－４０１．３３６ｋＪ·ｍｏｌ－１．     

制备高比表面积碳化硅的几种影响因素

采用溶胶凝胶法，以蔗糖和正硅酸乙酯(TEOS)为原料，草酸为TEOS水解的催化剂，制备均相碳化硅前驱体，在氩气氛和高温条件下(1 350～1 600 ℃)将碳化硅先驱体进行碳热还原，制备出高比表面积的SiC。考察了水/TEOS物质的量的比、碳/硅物质的量的比及镍盐等因素对碳化硅比表面积的影响。结果表明，当n_water/n_TEOS=7.5，n_C/n_Si=4时，适宜的镍催化剂(n_Ni/n_TEOS=0.005)，凝胶形成的时间最短，镍盐的加入可使碳热还原温度降低200 ℃。     

A new C21-steroidal glycoside from Cynanchum stauntonii

A new C21-steroidal glycoside with two known compounds were isolated from the root of Cynanchum Stauntonii.Based on thespectral analysis,including MS,1H NMR,13C NMR,DEPT,1H-1H COSY,13C-1H COSY,HMQC and HMBC,their chemicalstructures were determinated as glaucogenin-C 3-O-a-L-cymaropyranosyl-(1→4)-b-D-digitoxopyranosyl-(1→4)-β-D-canaropyranoside(1),stigmasterol(2)and ursolic acid(3).     

气相色谱质谱联用仪与微机的数据传输和处理

报道了一种用于气相色谱质谱联用仪和微机之间实现数据传输和处理的方法。方法可更有效地利用质谱仪采集的数据，解决了工作站处理数据的局限性。经数据格式转换，原始数据可以在微机上实现色谱峰再现，从而为色谱条件的优化和定量数据处理创造了条件。     

Photocatalytic Oxidation of Aniline in the Gas Phase Using Porous TiO2 Thin Films

The gas-phase photocatalytic oxidation of aniline on a new kind of porous nano-TiO₂ composite films is investigated. The composite film was prepared on glass fiber with the water glass as binders and dilute H₂SO₄ solution as solidifying reagent. The surface characters were observed by scanning electron microscope. The photocatalytic degradation of aniline on the composite films was carried out in a TiO₂/UV system. Some important factors affecting the photodegradation, such as the concentration of TiO₂, the initial concentration of aniline, and the existing water vapor, are also studied. The product of photocatalytic oxidation was detected by Fourier transform-Infrared. The partial intermediate products were absorbed on TiO₂ surface, which resulted in catalyst deactivation. But when it was irradiated under UV illumination or solar irradiation for some time, the catalyst could be reused without loss of catalytic activity. Translated from the Journal of Wuhan University (Natural Science Edition), 2005, 51(2) (in Chinese)     

氮化铁催化剂的制备及其苯胺催化加氢性能

用α－Ｆｅ２Ｏ３与氨气程序升温还原方法制备出不同温度氮气的氮化铁系列催化剂。通过ＸＲＤ测试对氮化过程中的晶相转变进行了分析。在中压反应装置上考察了氮化铁系列催化剂上苯胺加氢活性以及反应条件对苯胺加氢反应活性的影响。结果表明，在７００℃氮化制香的氮化铁催化剂显示有较高的苯胺加氢活性，在氢压为３．０ＭＰａ，温度为２５０℃，ｎ（Ｈ２）／ｎ（ｏｉｌ）＝１８，液体空速（ＷＨＳＶ）为０．３ｈ＾－１时，该催化剂     

A Minor New Flavone from Scutellaria baicalensis Georgi

A new flavone,6,2′-dihydroxy-5,7,8,6′-tetramethoxyflavone,was isolated from the roots of Scutellaria baicalensis. Its structure was established on the basis of spectral evidences.     

Cu-Zn-Sn体系富Sn区液相限的研究

近些年来,无铅低熔点填料日渐引起人们的兴趣,且将得到广泛的应用。Cu-Zn-Sn合金正是无铅低熔点填料的一种基本合金。该体系相图虽有一些报道,但他们的研究只涉及富铜区(>50Wt％)的液相限和等温截面(500℃)。我们颇感兴趣的富Sn区的液相限,尚未见文献报道,因此测定该体系富Sn区的液相限是必要的。关于Cu-Zn-Sn体系的三个相关二元体系,已有文献报道,也较成熟。对于Cu-Zn体系,富Zn区600℃以下存在两个转熔反应,其转熔点分别为Q(～88Wt％Zn,598℃),W(97.5-98.5Wt％Zn,424℃);Cu-Sn体系富Sn区有一个转熔反应,其转熔点