排序方式: 共有142条查询结果,搜索用时 375 毫秒
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玻璃防雾技术的研究进展 总被引:5,自引:0,他引:5
本文简单介绍了玻璃表面防雾的几种基本原理,综述了国内外以防雾为目的的玻璃表面改性的研究进展,并对该技术的发展趋势做了论述。 相似文献
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在赤铁矿-石英浮选体系中疏水细菌的作用 总被引:1,自引:0,他引:1
最近报道的文献表明,微生物有可能作为浮选药剂。本研究将非病源性疏水暗红球细菌(Rhodococcus opacus,缩写为R.opacus)作为赤铁矿-石英体系中的浮选药剂。对经微生物预处理前后的矿物进行了电泳迁移率测定、接触角测定、扫描电镜分析和微量浮选试验。微生物与矿物的相互作用使得矿物表面化学性质发生明显变化。赤铁矿与石英混合物的微量浮选试验表明。通过生物预处理,浮选赤铁矿颗粒和抑制石英颗粒是可能的。在所测定的pH范围内,可用DLVO理论解释与生物作用后石英颗粒Zeta电位、接触角和浮选行为的变化。对于赤铁矿,该理论仅适于预测在有限的pH范围内的吸附现象。 相似文献
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通过对提高细菌纤维素产量的不同途径进行归纳对比,最终发现细菌纤维素产量的提高不仅依赖于培养基和工艺条件的优化,更取决于高溶氧、低剪切力培养方式及设备的改进。由代谢通量分析可知需通过遗传改造、诱变等方法,减少副产物生成,提高BC的产率。 相似文献
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Optimization of extraction and determination of emodin from Polygonum cuspidatum Sieb. et Zucc. products by HPLC-DAD 总被引:1,自引:0,他引:1
A uniform experimental design procedure was used to investigate the effects of some operating parameters on the extraction of emodin from Polygonum cuspidatum Sieb. et Zucc. products. Variables tested were volume ratio of material to solvent, size of material, extraction time and temperature and composition of extraction solvent (mixtures of acetone-water). Each variable was tested at seven levels; 7 experiments were performed in random order. Analyses of the extracts were performed by high-performance liquid chromatography with diode array detection(HPLC-DAD). Analytical responses were processed by using a forward regression analysis, in order to find polynomial function describing the relationship between variables and responses. For all the analytes the experimental conditions for providing the highest extraction yield inside the experimental domain considered were found. Finally, a simple, rapid and accurate analytical method was developed for the determination of emodin by high performance liquid chromatography. The separation is achieved within 25 rain on an ODS column using methanol and water as gradient mobiles. Emodin can be quantified by using external standard method detecting at 436 nm. Good linearity is obtained with correlation coefficient exceeding 0.9986 and the detection limit and the quantification limit are 1.53 and 3.23 mg/L respectively. This method shows good reproducibility for the quantification of the emodin with intra-day and inter-day relative standard deviation less than 2.3% and 5.6% respectively. Under optimized extraction conditions, the recovery of the standard is 96.5%. The validated method is successfully applied to quantify the emodin in seven Polygonum cuspidatum sieb. Et zucc. products, which provided an idea for the pre-treatment of determination of active compounds in traditional Chinese medicines. 相似文献
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卢红梅 《计算机光盘软件与应用》2013,(5)
目前在学校内,大家的生活节奏都非常的快,对于学生来说,需要不时的购买书籍来进行学习充电,传统意义上的去书店购买书籍,不仅费时费力,还会产生较多的花费。同时,学校内每年毕业生使用过的部分书籍无法得到有效的处理,而这部分书籍恰恰是在校学生学习中所需要的。因此,开发一个基于校园网络的网上书城就十分有必要。鉴于此,本文选择网上书城系统为研究对象,针对相关的设计问题进行了分析和阐述,希望本文的研究能够为相关领域提供一些借鉴和参考。 相似文献
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