Formation of anisotropic polymer colloids by disparate relaxation times

We show that coupling between a fast and a slow relaxation time causes the spontaneous formation of protrusions in colloids made of cross-linked polymers. The volume of the protrusions can be controlled by adjusting the ratio between the relaxation times. This, in principle, results in particles with levels of anisotropy that can be made "to order".     

Analytical application of Cherenkov radiation

Studies were made to establish the possibilities and limitations of the photometric application of Cherenkov radiation. The colour quenching brought about by various coloured substances can be utilized for Cherenkov photometric measurements. The colour quenching is the strongest in the case of yellow, and the least strong for blue; accordingly, the slope of the linear logarithmic correlation between the efficiency and the concentration is higher for yellow than for blue. Glass and plastic vessels alike can be used for the measurements. The measurements have the greatest sensitivity in the case of the external standard. With the aid of an external standard, measurements of very high sensitivity can be made under isotope-free conditions.     

Reaction behaviour of monomeric β-ketoesters, 4. Polymer network formation by Michael reaction of multifunctional acetoacetates with multifunctional acrylates

Based on the Michael reaction of multifunctional acetoacetates with multiacrylates, in the presence or absence of dimethacrylates, tailor made matrix materials can be prepared. This can be achieved in a one- or two-step process. The Michael addition (first step) can be followed by radiation curing of excessive acrylate (second step).     

Exploring the complexity of aerosol particle properties and processes using single particle techniques

The complex interplay of processes that govern the size, composition, phase and morphology of aerosol particles in the atmosphere is challenging to understand and model. Measurements on single aerosol particles (2 to 100 μm in diameter) held in electrodynamic, optical and acoustic traps or deposited on a surface can allow the individual processes to be studied in isolation under controlled laboratory conditions. In particular, measurements can now be made of particle size with unprecedented accuracy (sub-nanometre) and over a wide range of timescales (spanning from milliseconds to many days). The physical state of a particle can be unambiguously identified and its composition and phase can be resolved with a high degree of spatial resolution. In this review, we describe the advances made in our understanding of aerosol properties and processes from measurements made of phase behaviour, hygroscopic growth, morphology, vapour pressure and the kinetics of water transport for single particles. We also show that studies of the oxidative aging of single particles, although limited in number, can allow the interplay of these properties to be investigated. We conclude by considering the contributions that single particle measurements can continue to make to our understanding of the properties and processes occurring in atmospheric aerosol.     

Conversion of N-aromatic amides to O-aromatic esters

[reaction: see text] N-Aromatic secondary amides can be transformed into O-aromatic esters in high yield via N-nitrosamide intermediates. The amides can be generated in situ from the corresponding aromatic amines or nitro compounds, and phenols can easily be made from the esters. The reaction can be modified by addition of methyl methacrylate or toluene at 0 degrees C to give polymerization or deamination, respectively. The rearrangement mechanism may involve radical formation and recombination.     

A NEW METHOD TO PREPARE BLUE MEMBRANE BY REMOVING THE CATIONS FROM THE PURPLE MEMBRANE BY ELECTROLYSIS

The purple membrane of Halobacterium halobium will change to the blue membrane when the cations bound to the membrane are removed. Here we introduce a new method to remove the cations by applying a moderate potential (20 V) between two platinum electrodes in a chamber containing a purple membrane solution. The purple membrane is deposited on the anode where the cations are removed by the low pH near this electrode due to the electrolysis of water. The blue membrane made by this method seems identical with blue membrane made by other methods but it can be made more quickly and in large quantities.     

PMMA型非线性光学膜的制备及其极化取向

采用封管反应, 以较高产率(80%以上)合成了一种PMMA型的极化非线性光学聚合物材料. 该材料具有很好的成膜性, 用电晕极化的方法使其旋涂膜中的生色团极化取向, 并利用偏振红外光谱和偏振紫外光谱等方法, 对膜中生色团极化前后的取向进行了研究.     

Acyl hydrazides as peptoid sub-monomers

The use of acyl hydrazides as peptoid sub-monomers is investigated. We demonstrate here that azapeptoids derived entirely from acyl hydrazides can be made conveniently and efficiently using standard peptoid sub-monomer chemistry. Structural studies reveal that the main chain amide bond in these molecules predominantly adopts a trans conformation. A high-quality one bead one compound library of tetramers was made by split and pool synthesis and we found that the identity of the molecule on a single bead could be determined by tandem MALDI mass spectrometry.     

PMMA基微流控芯片的准分子激光制备方法研究

采用准分子激光微加工技术在PMMA表面加工出了微混合器芯片.实验结果表明,采用准分子激光微加工技术可以加工出尺寸基本符合要求的、连续的、表面光洁度髙和边界整齐的微通道,可以加工出结构复杂的微流控芯片.     

Tungsten and molybdenum co-precipitation by α-benzoinoxime for activation analysis of tungsten

The co-precipitation of tungsten and molybdenum by α-benzoinoxime has been studied. Comparison of relative yields for both elements is made. Results showed coincidence and let conclude that molybdenum can be used as tracer to calculate sample to standard relative yield for tungsten. Analyses of water samples for tungsten were made and results were also presented.     

疏水催化剂用于水中氚回收的实验研究

本文简要介绍了自制的几种疏水催化剂的主要特性,采用这些催化剂进行了室温下的H—T同位素交换实验,初步考察了氢气流速对催化活性的影响。实验表明,催化剂的催化活性较高,能够用于室温下从氚水中回收氚。     

Voltammetric measurements with microelectrodes in low-conductivity systems

It is shown that voltammetric measurements can be made in solutions of low conductivity and low dielectric permitivity by using appropriate microelectrodes, the oxidation of ferrocene in toluene+ acetonitrile being used to explore the behaviour. At high concentrations of acetonitrile, measurements can be made at low or zero concentrations of supporting electrolyte; with decreasing concentration of acetonitrile, increasing concentrations of supporting electrolyte are required to determine the voltammetric curves. Simple corrections for ohmic potential drops in the solution can be applied but the procedures fail for solutions of very low dielectric permittivity, probably because of ion-pair formation near the electrode surface.     

电化学技术在选磷回水利用中的应用

研究表明,浮选磷矿的废水经电化学处理后可循环利用．通过改进的方法测定废水中悬浮颗粒的ζ电位和废水的透光率,可确立电化学处理的适宜参数．     

染料敏化纳米晶太阳能电池

半导体纳米晶颗粒形成的膜具有非常大的比表面积，其表面上可以吸附大量的染料分子，因而可以有效地吸收太阳光，并将其转化为电能。本文介绍了染料敏化纳米晶太阳能电池的基本原理以及电池的结构。从电池各个组成部分分别介绍了染料敏化纳米晶太阳能电池的发展及其研究现状。     

Infrared studies of cryogenic transitions in poly(ethylene terephthalate)

Measurements of infrared absorbance as a function of temperature down to 77°K have been made on poly(ethylene terephthalate). Transitions observed by other techniques such as torsion pendulum measurements are reflected in the infrared measurements by an abrupt change in the slope of the absorbance versus temperature. The infrared measurements are made on bands of known structural origin so the structures contributing to each transition can be determined. The β transition is shown by infrared to be a composite of two peaks with the lower-temperature portion arising from the amorphous regions and the higher-temperature portion from the crystalline regions.     

沙菜属三种经济藻类氨基酸与微量元素含量及其意义

首次报道了沙菜属Ｈｙｐｅｎａ３种经济藻类的１６种氨基酸和１２种元素的含量及其测定方法,结果显示有补益的微量元素含量较高,常见的１６种氨基酸含量也很齐全,提示其提取物可作食品添加剂,其粗品可作动物饲料添加剂。     

The role of 70-80% perchloric acid as oxygen donor and the oxidation potentials made available

A study has been made of the probable oxidation potentials provided by perchloric acid in the concentration range 70-80 %. The effect of acid concentration and temperature on the oxidation of chromium, vanadium, cerium, and manganese has been investigated. Available oxidation potentials appear to be 2.0-2.1 V or higher. The monohydrate of perchloric acid, HClO(4).H(2)O, containing 84.6% of perchloric acid, has been made commercially available and authorized for distribution by common carrier. It can be diluted to give acid concentrations from 73.6% (corresponding to HClO(4).2H(2)O) upwards. Perchloric acid mixed with sulphuric acid is equivalent to high concentrations of perchloric acid and can be used for dissolution of ores and destruction of organic matter.     

胶束荧光法测定维生素B_2含量

维生素B_2(核黄素)为人体内黄酶类辅基的组成部分,参与人体内的生物氧化作用。药典规定其含量测定用分光光度法,文献报道有高效液相色谱法、荧光法等。但因维生素B_2(V_(B2))遇光易分解,尤其在碱性水溶液中,极易变质。其降解产物为感光黄素,二氢核黄素,光化色素等,因此给测定的准确度和灵敏度造成一定的麻烦,为了提     

Incompletely symmetric non-bloch electron states in perfect cubic crystals. II. Density of states in the FCC lattice

The electron density of both the perturbed and unperturbed crystal can be made up of individual terms described by the basis functions of irreducible representations of the crystal point group. For the perfect FCC lattice, a detailed comparison was made between the density of states, calculated in terms of the LCAO wave functions classified according to representations of the crystal point group, and the density of states, provided by the Bloch theory.     

Raman-Spektroskopie und Molekülstruktur

The substitution pattern of benzene derivatives can be determined by means of a series of questions on characteristic Raman bands; frequency range, relative intensity, and degree of polarisation must be considered. Mono-, ortho-, meta-, and para-di-, and 1,3,5-tri-substituted derivatives can be recognised particularly well. Assignments made from Raman spectra appear to us to be more reliable than those obtained from characteristic infrared bands.