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61.
Statistical studies of branched ester latex and paint properties 总被引:3,自引:0,他引:3
R. A. Prior W. R. Hinson O. W. Smith D. R. Bassett 《Progress in Organic Coatings》1996,29(1-4):209-224
Vinyl versatate, butyl acrylate and 2-ethylhexyl acrylate were compared as comonomer, for colloid-stabilized vinyl acetate latex polymers to assess their impact on latex coating properties. Vinyl versatate afforded advantages in scrub resistance, gloss, hydrophobicity and higher glass transition temperatures. Butyl acrylate developed better wet adhesion efficiency, gel content and hiding efficiency. 2-Ethylhexyl acrylate offered performance comparable to butyl acrylate in hiding efficiency, lowering copolymer glass transition temperatures, and gloss development. Combinations of these monomers, in many instances, afforded a better balance of performance properties than individual monomers alone. In the subject study, a simplex-centroid design was utilized to statistically map polymer compositions for determining the effect of comonomer composition on latex and paint film properties. In addition to developing contour maps of polymer and paint properties as a function of composition, a technique for studying structure-property relationships is presented. 相似文献
62.
In this paper the modelling, analysis and optimization of millimeter wave oscillatorsare investigated by using the a frequency-domain harmonic balance technique (FDHB), where theexternal-circuit impedances looking outside from the active device are calculated with a combinedtechnique of modes expansion, Galerkin, and collocation methods. The optimization results arein agreement with the experimental ones, which show the reliability of the presented model andoptimization. 相似文献
63.
Structure-activity studies of human tumour necrosis factors 总被引:3,自引:0,他引:3
Van Ostade Xaveer; Tavernier Jan; Fiers Walter 《Protein engineering, design & selection : PEDS》1994,7(1):5-12
The mechanism by which tumour necrosis factors (TNF and lymphotoxin,also called TNFß and TNFß respectively) exerttheir cytotoxic activity on many malignant cells, remains largelyunknown. Furthermore, the broad array of differentiation (geneinduction) and mitogenic activities towards many primary cellsis still a subject of intensive investigation. TNF is an importantmediator in inflammation, immune responses and infection-relatedphenomena and these activities contribute to the severe toxidtyseen when TNF is used as an anticancer agent. The first stepin the mechanism of action is the specific binding of the ligandto its receptors and dissection of the molecular mechanism involvedin this interaction is the subject of this review. The reasonsfor the interest in this aspect are obvious: first, the developmentof strong antagonistic TNF analogues can be useful in dampeningthe potentially lethal or debilitating effects of an overproductionof the cytokine (as in septic shock or rheumatoid arthritis).Secondly, since two distinct TNF receptors exist, constructionof TNF muteins that distinguish between both types may leadto derivatives of this plekrtropic agent with a more restrictedbiological activity pattern. Ideally, one would like to developa TNF mutant that has retained its cytotoxic action on tumourcells without inducing the deleterious systemic toxteity. Suchan optimized TNF molecule could become a potent anticancer agent 相似文献
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The semiconductor thin disk laser is a new type of semiconductor laser. This work gives the basic operation function of the semiconductor disk laser, and analyses the heat effect by the experimentally measured photoluminescence spectrum of the laser chip at different pump power and different temperatures. We can see that: with increasing pump power, the thermal effect of the gain material becomes seriously and causes the saturation of carrier lifetime, so the electron-hole pair created in the absorbtion lay... 相似文献
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68.
活性炭中甲烷水合物的生成动力学 总被引:6,自引:1,他引:5
在温度275.75-279.95K和压力5.6-9.6MPa的静置条件下,测定了14组甲烷水合物在活性炭中的生成动力学数据(压力-时间关系),分析了甲烷水合物在活性炭中生成的物理过程,结合边界层理论和结晶学原理,提出了单液膜传质控制机理的生成动力学模型,并求得了解析解,使用Levenberg-Marquardt方法拟合模型参数,模型预测值与实验值符合良好。 相似文献
69.
讨论了多重帐户问题在计算机网络管理中诸多弊端。提出以目录服务(Novell NDS)为基础,实现跨平台(NetWare、WindowsNT和Solaris)的帐刻统一管理的方案及详细实施实例。 相似文献
70.
Tatsuro Kijima Kouji Ohshima Hideo Kise 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1994,59(1):61-65
Racemic amino acid esters were optically resolved via hydrolysis in organic solvents by the catalysis of an industrial alkaline protease, “Alcalase”. The products which were composed mainly of L-amino acids were insoluble and easily separated by filtration. The activity of the enzyme and enantiomeric excess of the products were significantly dependent on the nature of solvent and the water content in the reaction media. Generally, high values of enantiomeric excess were obtained at low water contents. Many natural and unnatural amino acids were resolved by this method. 相似文献