实时生物分子相互作用分析技术用于链霉亲和素-生物素化抗体的层层组装研究

使用生物分子相互作用分析 ( Biomolecular interaction analysis,BIA)技术实时监测了在链霉亲和素表面层层组装亲和素 -生物素化抗体多层膜的过程 ,结果表明 ,通过链霉亲和素与生物素之间的强亲和作用 ,能够在表面形成均一的多层膜 ,并用实时 BIA技术求得了每层蛋白质的表面浓度 .对于生物素化抗体 ,单层吸附表面浓度为 1 .32 ng/mm2 ;对于链霉亲和素 ,单层吸附表面浓度为 2 .93ng/mm2 .同时对蛋白质在表面的排列状态进行了探讨

Crystal form transition during heating of solvent-induced crystalline syndiotactic polystyrene

The phase transition of two kinds of solvent-induced crystalline syndiotactic polystyrene (sPS). gamma-sPS and delta(c)-sPS, has been studied via WAXD and DSC. gamma-sPS transform to a-sPS at 195-225 degrees C before melt during heating, whereas delta(e)-sPS transform to first gamma-sPS and then a-sPS at 100-200 degrees C and 200-215 degrees C, respectively. The transition of delta(e)-gamma and gamma-a occurs for below melting point of sPS indicates they are all solid-solid transition.

Molecular orientation of copper phthalocyanine in thin films and their gas-sensing properties

Copper phthalocyanine derivative Langmuir-Blodgett (LB) films were prepared by vertical dipping and horizontal lifting methods. Molecular orientation of copper phthalocyanine derivative in thin films was studied by polarized UV-Vis spectra. The relationship between the molecular orientation of copper phthalocyanine in LB films and their gas-sensing properties was investigated.

Electroluminescent properties of the Tris-(acetylsalicylate)-terbium (Tb(AS)(3))

The solubility of [Tris-(acetylsalicylate)-terbium] [Tb(AS)(3)] is improved to a greater extent than [Tris-(salicylate)-terbium] [Tb(Sal)(3)] following introduction of a flexible acetyl group. Th3+ binds with acetylsalicylate in solution at low pH value and the resultant Tb(AS)(3) has good solubility in chloroform. A Green EL device with the structure ITO/PVK/PVB:PBD: Tb(AS)(3)/ PBD/Al has been fabricated based on soluble Tb(AS)(3), in which Tb(AS)(3) was first used as an emissive center doped with PVK and PBD. The hole-transporting layer and the emissive layer were formed by spin coating. The device exhibited a highly pure characteristic green light of Tb3+. (C) 2001 Elsevier Science B.V. All rights reserved.

稀土基汽车尾气催化剂的催化活性研究

利用浸渍法制备了一系列含Ce La稀土助剂改性的Pt Rh三效催化剂 ,采用各种表征手段和高温抗硫水热老化实验 ,考察了Ce La稀土对Al2 O3 载体的热稳定性和催化剂活性的影响 .研究结果表明 ,稀土La2 O3 的添加主要改善了载体Al2 O3 的高温高比表面性能 ;而CeO2 的引入则明显地提高了CO和NO的催化转化活性 ,但对HC的转化几乎无影响 ,也促进了催化剂的抗硫水热老化性能 ,并且显著地拓宽了催化剂的三效窗口 .这主要归因于CeO2的添加 ,它改善了催化剂上CO ,HC和NO间的相互作用以及CeO2 所特有的储氧功能

Synthesis and characterization of (phenolphthalein/4,4 '-thiodiphenol) PES copolymers

Copolymers based on monomers phenolphthalein (PP)/4,4'-thiodiphenol (Bis-T)/4,4'-dichlorodiphenylsulfone (DCDPS) were prepared by a route involving the toluene, N-methyl-2-pyrrolidone and anhydrous potassium carbonate synthesis. The range of optimum reaction temperature was between 185 and 195 degrees C. The copolymers were characterized by C-13 NMR, differential scanning calorimetry (DSC) and torsion braid analysis. It was found that all of the copolymers were random and homogeneous and their glass transition temperatures (T-g) decreased linearly with an increase of Bis-T contents in the copolymers. The thermal stability determined by thermogravimetry analysis in air atmosphere indicated that the copolymer had better resistance to thermo-oxidative degradation. Dynamic mechanical measurement showed that (PP/Bis-T) PES copolymers containing 0-50 mol% of Bis-T components had two secondary relaxations. (C) 1998 Elsevier Science Ltd. All rights reserved.

Pd/C催化剂在处理NO反应中的催化行为

研究了不同活性炭负载的Pd催化剂在NO＋CO反应中和单独处理NO时的催化行为．结果表明，Pd的引入可大大提高催化活性，且活性与Pd含量呈顺变关系．不同的载体对催化剂活性有很大影响．在NO＋CO反应中，由煤质炭为载体制得的催化剂活性很高，在低于550K时NO即可达到100%转化，而在单独NO时，由山桃核炭制得的催化剂有较高的活性，在低于650K时NO可达到100%转化．催化剂活性的差异与活性炭表面性质有关．当反应体系中有还原物质CO存在时，活性炭作为载体，Pd在其上的分散对活性有重要影响；当体系中没有还原物质时，活性炭作为还原剂参与反应，这时活性炭本身的性质变得十分重要.

Single-chain single crystals of gutta-percha

Single-chain single crystals of gutta-percha have been observed by transmission electron microscopy of atomizer-sprayed particles deposited from a very dilute solution in chloroform onto a carbon film which had a filter paper wetted with ethanol in contact with its under side. Selected-area electron diffraction patterns of crystals having no definite crystal profiles showed that the crystals were of the low-melting crystalline form and that the chain segments in the single crystals were standing up from the substrate during crystallization. In cases of single crystals showing sharply defined crystal profiles, electron diffraction patterns showed that they were neither of the low-melting form nor the high-melting form. The structure of this new crystalline modification needs further studies.

Preparation and crystal structures of LaCl3(15-crown-5) and [LaCl2(phen)(H2O)(2)(mu-Cl)](2)center dot(15-crown-5)center dot MeCN

LaCl3(15-crown-5), I was prepared by the reaction of LaCl(3)nH(2)O with 15-crown-5 and bipy (2,2'-bipyridyl). [LaCl2(phen)(H2O)(2)(mu-Cl)](2) .(15-crown-5). MeCN, II, was crystallized from a mixture of LaC1(3) . nH(2)O, phen (1,10-phenanthroline) and 15-crown-5 in MeOH/MeCN, Crystal structures of these two complexes have been determined by X-ray methods. The La(III) ion in I is coordinated by three Cl anions and five oxygen atoms of a crown ether. The two metal ions in II are bridged by two Cl anions and the crown ligand is hydrogen-bonded to the coordinated water molecules to form polymeric... crown/cation/cation/crown... chains.

MEDIATORLESS HYDROGEN-PEROXIDE ELECTRODE BASED ON HORSERADISH-PEROXIDASE ENTRAPPED IN POLY(O-PHENYLENEDIAMINE)

A mediatorless H2O2 sensor based on coelectropolymerization of horse radish peroxidase (HRP) and o-phenylenediamine (o-PD) is described. The electrode responds to H2O2 in a few seconds and gives a current density of 73.3 nA 1 mu mol(-1) cm(-2) at -100 mV

PREPARATION AND PROPERTIES OF THREAD-THROUGH COPOLYMERS OF POLYETHYLENE WITH POLYISOPRENE

Graft copolymers of polyethylene (PE) with polyisoprene (PI) were synthesized through polymerization of ethylene in toluene solution of PI (cis-1,4-: 95%; 3,4-: 5%) using a homogeneous V(acac)3/Et3Al2Cl3 catalyst. Copolymers are formed when the growing po

COMPATIBILIZATION AND STRUCTURE OF POLY(PROPYLENE) NYLON-12 BLENDS

In this paper, scanning electron microscopy (SEM), differential scanning calorimetry (DSC) and wide-angle X-ray diffraction (WAXD) were used to study the structure and compatibilization of poly(propylene) (PP)/nylon-12 (PA 12) blends. The compatibilizatio

DSC AND C-13 NMR-STUDIES OF ETHYLENE-PROPENE COPOLYMERS PREPARED BY A HIGHLY-ACTIVE AND STEREOSPECIFIC CATALYST

Ethylene-propene copolymers (EPR) were synthesized at different feed compositions using a highly active and isospecific MgCl2-supported Ti-based catalyst. The thermal behavior of EPR was studied by differential scanning calorimetry, the heterogeneity by f

CATALYTIC BEHAVIOR OF METAL-IONS LOCATED AT DIFFERENT SITES OF HETEROPOLYCOMPOUNDS

It was discovered experimentally that heteropolymolybdophosphoric acids (HPA) with Keggin and Dawson structure are inactive for H2O2-decomposition, while their salts (Fe3+, Cu2+, Co2+ and Mn2+) all possess more activity. It could be concluded that the act