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991.
以二乙烯苯和双丙烯酸多缩乙二醇酯为交联剂、聚醋酸乙烯酯(PVAc)或它与醋酸丁酯(BAC)的混合物为致孔剂、BPO为引发剂,用悬浮聚合随后水解的方法制得了部分水解聚(丙烯酸甲酯-醋酸乙烯酯-甲基丙烯酸甲酯)[HP(MA-VAc-MMA)]多孔载体,研究了PVAc及(PVAc+BAC)用量、分子量及混合比对HP(MA-VAc-MMA)孔结构的影响。结果表明,当PVAc的M>2.5×105,PVAc/BAC为2.3,用量为10~20%时,可制得孔隙率较高,孔径分布较窄,孔表面积较大的多孔载体。这种载体适用于微生物固定化。 相似文献
992.
The quadruple complex formed by terbium with 4-chlorosalicylic acid (CSA), EDTA and cetyltrimethylammonium bromide (CTMAB) has been used for the sensitive spectrofluorometric determination of terbium in mixed rare earths. The effect of the experimental conditions on the fluorescence intensity was defined. Under the optimum conditions selected, the fluorescence intensity was linear with the terbium concentration in the range of 3.0 x 10(-8)-1.0 x 10(-5) mol/L with a detection limit of 8.0 x 10(-9) mol/L (S/N = 3). It has been satisfactory for the determination of terbium in mixed rare earths with good recovery. 相似文献
993.
后关系型数据库Caché的应用研究 总被引:3,自引:0,他引:3
对后关系型数据库Caché进行研究,首先分析了Caché的存取数据模型、Web架构以及CSP的工作原理,它提供了健壮的对象式数据存取、高性能的SQL查询和多维数据存取方式.然后用CSP开发一个简单的基于Web应用,来演示基于Caché数据库的Web应用开发.得出Caché能够加速Web应用开发,提高特殊事务处理的速度,加快对事务型数据的实时查询,系统维护工作小. 相似文献
994.
995.
Mariza Pires de Melo† Tania Cristina Pithon Curi Rui Curl Paolo Di Mascio Giuseppe Cilento 《Photochemistry and photobiology》1997,65(2):338-341
Peroxidase activity in neutrophils is higher than in thioglycollate macrophages, while in lymphocytes this enzyme activity is very low. Indole-3-acetic acid is oxidized by peroxidase and the role of this enzyme in the cytotoxic effect of the compound was evaluated by measuring oxygen consumption, light emission and cell death in neutrophils, macrophages and lymphocytes. The increase in light emission, oxygen consumption and rate of cell death in cells cultured in the presence of indole-3-acetic acid presented a direct correlation with the peroxidase activity of the cells as follows: neutrophils > thioglycollate macrophages > resident macrophages > lymphocytes. Indeed, in lymphocytes that possess very low peroxidase activity, indole-3-acetic acid did not result in an increase in light emission or oxygen consumption and it was not cytotoxic. 相似文献
996.
997.
非线性无穷时滞微分系统的稳定性 总被引:1,自引:0,他引:1
本文主要内容是:(1)在局部条件下,建立了一类具有无穷时滞的非线性的正、反向积分微分不等式;(2)结合常数变易法和Liapunov函数法(不必寻找P-函数),利用所建立的不等式研究了非线性无穷时滞微分系统的稳定性;(3)举例说明了本文定理的应用和优点。 相似文献
998.
Jun Lu Rui Huang Yong Chen Liangbin Li 《Journal of Polymer Science.Polymer Physics》2006,44(21):3148-3156
Morphologies of extended‐chain crystals with different characteristics were observed with scanning electron microscopy (SEM) in the high‐pressure crystallized polyethylene terephthalate/polycarbonate (PET/PC) blends. The crystals memorize their nucleation and growth process, which reveal an involvement of different mechanisms simultaneously. The presence of sliding diffusion during crystal thickening is indicated by a wedge shape of some crystals, while bent crystals suggest the occurrence of transesterification in the formation of the large extended‐chain crystals. The observation of two morphological features on one group of crystals shows that two mechanisms may work simultaneously. The connection between folded‐chain and extended‐chain crystals is demonstrated by the S‐shaped extended‐chain crystals as well as their direct morphological connection observed with SEM. Though transesterification plays the essential role in the formation of the large crystals, which acts in different aspects during the process, the thermodynamic driving force is the enthalpy gain associated with large crystals. This is a high‐pressure self‐assembly with a coupling between crystallization and transesterification, which may be instructive to grow such large crystals in similar polymer systems. © 2006 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 44: 3148–3156, 2006 相似文献
999.
In this paper, by applying a vector-valued inequality we obtained a decomposition theorem on Herz spaces over locally compact Vilenkin groups with new range 0 < q≤1. 相似文献
1000.
Evidence is presented in the literature that common fluorescence tracer/fuel mixtures used in engine experiments, 3-pentanone/isooctane
and biacetyl/isooctane, may decompose during extended use and storage. Investigations presented here show that preferential
evaporation of the tracer and not chemical decomposition is responsible for observed decreases in fluorescence signal strength
in these experiments. 相似文献