皂类液膜振荡器

实验发现了一类新型液膜振荡器,在油水两相之间进行成皂反应的过程中,界面附近出现了长时间规则的大幅度pH振荡,将W/O两相体系换成W1/O/W2三相体系,振幅从0.50 pH明显提高到2.88 pH.其中水相组成为CTAB溶液及NaOH溶液,油相组成为油酸的煤油溶液.同时,此类液膜振荡体系中亦存在明显的电势振荡和电导率振荡.为深入了解机理,进行了浓度影响测定,电极位置和种类的变化以及辅助实验等,提出了普遍化的机理,并进行了实验振荡曲线的拟合对比.这个机理指出,在膜反应批量进行的条件下,当反应速率与扩散成比例时,便会产生规则的周期现象.在一价皂液膜振荡器的基础上,通过替换或添加各种金属盐,形成了各类高价皂液膜振荡器,测定了反应过程中pH、电势及电导率的变化.经过同类化学振荡器的比较研究,结合金属离子与酸根之间的络合作用,得出了其中的一些规律.     

有机官能化MSU-x孔分子筛的界面特征

MSU- x是自 M41S系列介孔分子筛问世以来所合成的另一类新型介孔分子筛材料 ,它具有三维立体交叉排列的 " worm- like"孔道结构特征及采用中性模板剂、廉价无毒等诸多合成优点 [1～ 4],有着潜在的应用价值 .为了改善纯硅的介孔材料的表面和孔道性质 ,扩大其应用领域 ,除了在骨架引入金属离子或在其孔道中负载催化活性物质外 ,对介孔材料进行有机官能化制备无机-有机杂化材料改善其骨架和孔道性质是当前研究的热点之一 [5].正是由于活性有机基团的存在 ,使得这些材料可直接用于催化反应 ,或作为中间介质成为其它络合离子的主体 .由于有机基…     

电化学石英晶体微天平研究界面电场对DNA杂交的影响

采用电化学石英晶体微天平, 现场监测不同界面电场下完全匹配的靶标DNA和不完全匹配的靶标DNA分别与寡聚核苷酸探针分子杂交的过程. 结果表明, 电极表面荷正电时DNA表观杂交效率比电极表面荷负电时高, 但假阳性比较显著; 而电极表面荷负电时能有效地抑制错配杂交. 探讨了引入界面电场后探针分子取向和微观作用力对DNA杂交的影响.     

SiO2/α-FeOOH和SiO2/γ-Fe2O3微粒的界面研究

α－FeOOH微粒由于其表面高活性，在转变成γ－Fe2O3的热处理过程中容易烧结，一旦这种烧结现象发生，得到的γ－Fe2O3磁粉磁性能大大下降[1]．为了克服这一困难，目前采用在α-FeOOH微粒表面包敷有机物[2]和无机物[3]来隔离颗粒，阻止其聚集．其中SiO2表面包敷处理是最令人感兴趣的研究课题之一[4，5]．SiO2是一种难烙性的非磁性材料，它包敷在α-FeOOH微粒表面外，不仅可提高α－FeOOH转变成γ－Fe2O3的热处理温度，有利于得到外形完好、晶格完整的γ－Fe2O3磁粉，而且由包效层与内核之间的界面相互作用引起的表面各向异性常…     

Zero Current Potentiometry for Measuring the Interface Potential at the Electrode/Solution Interface. Theoretical and Experimental Study

A novel electrochemical approach has been proposed to measure the interface potential at the electrode/solution interface based on reconstructing the three‐electrode system of a potentiostat. In this work, the method was investigated both theoretically and experimentally. Mathematical expressions, describing current? potential characteristics, were derived. Zero current potential E_zcp was defined as the potential at which the current is zero based on linear sweep voltammetry, and was determined from the I? E curve to measure the interface potential. The experimental results obtained with the couples Fe(CN)₆^3?/Fe(CN)₆^4? and Co(NH₃)₆³⁺/Co(NH₃)₆²⁺ as examples agreed well with the theory. The proposed approach exhibits an excellent performance for measuring the interface potential due to the advantages of rapidity, high stability and accuracy.     

附加压力与分散系统的稳定性

较详细地讨论了附加压力与分散系统稳定性间的关系,指出分散相附加压力的降低是分散系统趋向稳定的根本原因。以乳状液为例,附加压力降低不仅减少了液滴间相互碰撞的概率,而且更重要的是,它与液滴表面形成牢固的保护膜密切相关。只有当液滴的附加压力趋近0时,分散系统才达到热力学上稳定的状态,此时乳状液已变成了微乳状液。上述讨论也基本适用于固/液分散系统。     

Wave propagation across a finite heterogeneous interphase modeled as an interface with material properties

Mechanical problems involving an interphase between two well-defined, and eventually different, materials are of interest. The aim of this paper is to present a simplified model that, for low frequency regime, is appropriate for this situation: an interface model with elastic and inertial properties. We present, together with the equations of motion, an identification procedure that is valid for any mass density profile along the thickness of the interphase. For evaluating the accuracy of the model, computations of the reflection coefficients in some relevant cases are shown. Besides, a finite element method is used as a benchmark for both the high and low frequency regimes. It is worth to be noted that the numerical test has been inspired by the problem of the interphase that is formed at the bone-implant boundary.     

Disjoining pressure and the film-height-dependent surface tension of thin liquid films: New insight from capillary wave fluctuations

In this paper we review simulation and experimental studies of thermal capillary wave fluctuations as an ideal means for probing the underlying disjoining pressure and surface tensions, and more generally, fine details of the Interfacial Hamiltonian Model. We discuss recent simulation results that reveal a film-height-dependent surface tension not accounted for in the classical Interfacial Hamiltonian Model. We show how this observation may be explained bottom-up from sound principles of statistical thermodynamics and discuss some of its implications.     

The secondary X-ray fluorescence and absorption near the interface of multi-material: Case of EDS microanalysis

A simple model is proposed to take into account secondary X-ray fluorescence and absorption effects near the interface. This model is based on the investigation of the shape change of the first derivative equation that can fit the sigmoidal EDS profile obtained when a high vacuum electron beam passes through the interface of two adjacent materials. The contribution of the photoelectric absorption of primary X-rays (characteristic and Bremsstrahlung) and the secondary fluorescence on the degradation of the X-ray spatial resolution can be easily quantified. The close agreement between the simulated (Monte Carlo simulation using the Casino software) and the experimental data serves to assess the reliability of this developed model.     

Interfacial mechano-chemical grafting in styrene-butadiene rubber/halloysite nanotubes composites

SBR/unmodified HNT composites were prepared by open-mill mixing and vulcanization. The results showed that HNT could decrease the scorch and optimum cure time, and play a significant role in reinforcing SBR vulcanizates. Mechano-chemical grafting at the interface between HNT and SBR was investigated by using infrared spectroscopy, X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM), solid-state ¹³C NMR spectra and bonded rubber content, etc. The results showed the shearing force during the mixing process can impel the grafting reaction of SBR onto the surfaces of HNT, which leads to interfacial chemical bonding between phenyl’s α-H of SBR and the surface groups of HNT with Si-OH or Al-OH. Thus, the mechanical properties of the composites were significantly enhanced.