Polymer resin library and the discovery of highly efficient polymer supported reagents and scavengers

Summary This paper is focused on the preparation of a library of highly efficient, tailor made, macroporous resins as supports for reagents and scavengers. From this library a macroporous resin, prepared with 40% cross-linking and with a porogen level of 300% in toluene gave a material superior to those presently available, and was shown to be highly efficient in the preparation of novel highly reactive polymer supported reagents, including scavengers and oxidants.     

New proof of two Berstein-Hilton theorems

With arguments of Homotopy Theory and without the assumption of finite type, we give short proofs of two classic theorems which deal with the co--type of a suspension and the homotopy class of a suspension map.

     

扬声器定心支片的非线性失真研究

本文在扬声器线性失真产生原因的分析基础上,设计了一种测量扬声器位移的新方法,并以大量的实验数据证明,大扬声器的结构中,定心支片的力学性能对扬声器非线性失真有极大地影响,指出于扬声器定心支片的研究,将有望成为一项新的课题。     

Analysis of the effect of malaria on lipid composition of rhesus plasma

The phospholipid distribution and the ratio of cholesterol-to-cholesterol ester have been determined for plasmas isolated from normal, fasted and P. knowlesi-infected rhesus monkeys. Compared to normal plasmas, the infected plasmas show phospholipid patterns with slight increases in phosphatidylcholine and larger decreases in lysophosphatidylcholine. The cholesterol-to-cholesterol ester ratio is always less than one in normal plasmas and greater than one for infected plasmas. There are no differences between samples isolated from fasting and non-fasting animals for any of the constituents examined.     

非导电微球悬浊系的介电谱弛豫机制的考察和界面信息的解析

研究了不同浓度电解质溶液中聚苯乙烯微球悬浊液的介电谱, 发现在40 Hz～110 MHz频率范围内出现了两个明显的弛豫. 在介电模型基础上对弛豫原因的理论分析结果表明, 千赫兹频域出现的弛豫是由粒子附近双电层中对离子的扩散所致, 兆赫兹附近出现的弛豫源于空间电荷在固/液界面的累积. 应用Hanai方法计算出体系内部的相参数, 获得了微球/溶液界面的电信息, 并给出了合理解释. 理论计算结果验证了模型和方法的适用性. 实验采用透析法调制样品, 有效地防止了体系内部粒子二次团聚的发生.     

Monomers containing substrate or inhibitor residues for copper amine oxidases and their hydrophilic beaded resins designed for enzyme interaction studies

Five styrenic monomers, four with aminoalkyl residues typical of copper containing amine oxidase substrates and one with a 2,6-dialkoxybenzylamine residue which mimics previously prepared selective substrate-like benzylamine oxidase inhibitors, have been synthesized and transformed into radical homopolymers, copolymers with N,N-dimethylacrylamide (DMAA), and hydrophilic beaded resins, designed for enzyme interaction studies aimed in finding new materials for highly biospecific chromatographic separations. The five monomers have given beaded resins of 125-500 μm swellable in water with a volume increase of 1200-1500%. The four aminoalkyl monomers have given water soluble copolymers some of which are good substrates of benzylamine oxidase (BAO), diamine oxidase (DAO) and lysyl oxidase (LO), up to 9.7 times better than elastin for LO.     

In‐Line Monitoring of Vinyl Chloride Suspension Polymerization with Near‐Infrared Spectroscopy, 1 – Analysis of Morphological Properties

It is demonstrated that during suspension polymerizations it is possible to monitor morphological characteristics of PVC resins such as bulk density, cold plasticizer absorption and average particle diameter in‐line and in real time using NIR spectroscopy. NIR spectra are obtained at different experimental conditions, showing that the spectra are sensitive to changes in the PVC properties. Standard mathematical procedures (partial least squares regression) are used to build empirical models and correlate the morphological properties with the obtained NIR spectra, allowing for monitoring of the PVC morphology in‐line and in real time.

     

Convectional, sedimentation, and drying dissipative structures of ethanol suspension of colloidal silica (110 nm in diameter) spheres

Convectional, sedimentation, and drying dissipative structural patterns formed in the course of drying ethanol suspensions of colloidal silica spheres (110 nm in diameter) were studied in a glass dish and a watch glass. Vigorous cell convectional flow was observed with the naked eye, and the patterns changed dynamically with time. Broad-ring-like sedimentation patterns were observed in the suspension state just before the suspension was dried up, and the principal macroscopic patterns of the drying patterns were also broad-ring, though the colorful and fine microscopic structures were observed from optical microscopy.     

Studies on lanthanoid sulphites: Part IV. Thermal decomposition of erbium sulphite trihydrate under various experimental conditions

Thermal behaviour of Er₂(SO₃)₃· 3H₃O has been studied by means of TG, DTG, DTA, DSC and EGA techniques. Experimental conditions were also varied, $\text{viz.}$ sample size, heating rate and the atmosphere.The dehydration starts slowly above 150°C but the release of water is rapid around 250°C. SO₂ gas is evolved slowly and simultaneously with H₂O. The anhydrous sulphite is formed below 300°C after which it decomposes through several reactions accompanied by a release of mainly SO₂, but also a small amount of SO₃ near 650°C. In air, there is a clear plateau in the TG curve between 600 and 800°C; the weight loss involved depends strongly on the sample size and heating rate, however. A plausible explanation for the plateau is the formation of a mixture of Er₂(SO₄)₃, Er₂O(SO₄)₂ and Er₂O₂SO₄. The next plateau around 900 – 1000°C corresponds to Er₂O(SO₄)₂ and Er₂O₂SO₄. In nitrogen atmosphere, the first plateau after the anhydrous sulphite appears later in the weight scale as compared to air. Although the position of the plateau corresponds to the sesquisulphide, it is according to X-ray diffraction results a mixture of Er₂O₂(SO₄) and Er₂O₃. In both air and nitrogen, the final reaction step above 1000°C is the formation of Er₂O₃.     

Rheology of water-in-water suspensions formed with lightly sulfonated ionomers

The formation and rheological properties of water-in-water suspensions formed by mixing a dilute nonaqueous solution containing a lightly sulfonated ionomer with an aqueous solution are described. The spheres formed via this process are composed of a very thin (approximately 2000 Å), ionically crosslinked gel membrane which separates the continuous aqueous phase from the encapsulated aqueous phase. The membrane itself is composed of the lightly sulfonated ionomer (i. e., sulfonated polystyrene) swollen with the nonaqueous solvent. Interestingly, surface tension measurements indicate that the sulfonated ionomer in this nonaqueous solvent has no significant interfacial activity. Viscometric measurements confirm that aqueous solvents containing these spheres have considerably enhanced viscosity even in the presence of high concentrations of a salt or acid. Thixotropic behavior is observed at low shear rates, whereas Newtonian behavior is observed at higher rates of shear (> 40 sec^–1). Cessation of stress reverts the viscosity to its initial value. Dilution studies show that the streamlines in the flowing exterior aqueous phase cause circulation of the aqueous fluid within the sphere. These results point to the fluid-like characteristics of the gel membrane, since transmission of the stress across the membrane is not dramatically inhibited. Comparison of the low shear rate data with the Mooney equation support these conclusion.