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141.
音乐课是一门艺术课。在音乐课教学中,教师如何有效地调控学生的注意力,激发学生的学习兴趣呢?笔者认为教师精湛的表演能达到以上两个目的。本文就音番教学中教师如何表演介绍笔者在教育教学实践中的探索。 相似文献
142.
A mathematical model of the dynamic behavior of countercurrent chromatography was proposed, and the model parameters, including the partition coefficient, the axial dispersion coefficient, the intraparticle diffusion coefficient and the external mass ransfer coefficient were calculated by the method of chromatogram moment analysis. Comparison of the experimental chromatograms of caffeine and theophylline determined in this work with the simulated curves computed by the proposed model showed fairly good agreement. Further, the difference between the average identified the partition coefficients by chromatogram moment analysis and the experimental values was small also, and the relationship between the external mass transfer rate and the linear velocity was similar to that obtained with solid-liquid chromatography. 相似文献
143.
Simple, reliable and sensitive analytical methods to determine anticariogenic agents, preservatives, and artificial sweeteners contained in commercial gargles are necessary for evaluating their effectiveness, safety, and quality. An ion chromatography (IC) method has been described to analyze simultaneously eight anions including fluoride, chloride, sulfate, phosphate,monofluorophosphate, glycerophosphate (anticariogenic agents), sorbate (a preservative), and saccharin (an artificial sweetener)in gargles. In this IC system, we applied a mobile phased gradient elution with KOH, separation by IonPac AS18 columns, and suppressed conductivity detection. Optimized analytical conditions were further evaluated for accuracy. The relative standard deviations (RSDs) of the inter-day's retention time and peak area of all species were less than 0.938% and 8.731%, respectively,while RSDs of 5-day retention time and peak area were less than 1.265% and 8.934%, respectively. The correlation coefficients for targeted analytes ranged from 0.999 7 to 1.000 0. The spiked recoveries for the anions were 90%~102.5%. We concluded that the method can be applied for comprehensive evaluation of commercial gargles. 相似文献
144.
根据胶原生物矿化的原理和方法,制备不同条件下的明胶生物矿化样品,通过红外光谱分析,发现磷酸钙、氯化镁的存在引起明胶分子中酰胺Ⅰ、Ⅱ、Ⅲ带显著褪化,明胶生物矿化与胶原生物矿化的紫外光谱曲线也有相似之处,表明明胶与钙、镁离子存在配位作用,明胶也可能作为生物矿化的模板材料。 相似文献
145.
146.
本研究利用溶胶-凝胶法,以硅胶为载体,制备了掺铕TiO2纳米光催化材料.重点研究了钆钛比、焙烧温度及镀膜次数不同时对产物的光催化活性的影响.并以太阳光作为光源,对甲基橙进行了光催化降解试验来评价制备的复合光催化材料的光催化性能.实验表明,其最佳铕钛比为1.0%,焙烧温度为550℃,镀膜次数为2次. 相似文献
147.
基于壳聚糖(CS) 与聚甲基丙烯酸(PMAA) 间的复合作用制备了CS 与PMAA的聚电解质复合型水凝胶. 利用荧光光谱研究CS 与PMAA 的相互作用,结果表明随介质环境pH 值的变化,凝胶中PMAA 的构象在压缩线团和伸展态之间变化,该凝胶具有溶解和释放稠环芳烃的能力,可望在稠环芳烃污水处理上获得应用. 相似文献
148.
149.
E. Raji Nair Swati Banerjee Satish Kumar M. V. R. Reddy B. C. Harinath 《Indian journal of clinical biochemistry : IJCB》2001,16(1):132-135
Proteins secreted into the culture medium byMycobacterium tuberculosis (M. tb) are shown to be source of antigens of immunodiagnostic interest. Anin vitro released 31 kDa antigen ESAS-7F isolated fromM.tb H37Ra culture filtrate by salt precipitation, SDS-PAGE and cation exchange fast protein liquid chromatography (FPLC) was shown
earlier to be a diagnostically important antigen fraction. In this report, we describe the isolation of ESAS-7F antigen using
monospecific antibody coupled to sepharose CL-4B column. The percentage recovery of ESAS-7F antigen using affinity chromatography
was approximately 8% of the total ES antigen proteins compared to 0.05% obtained by conventional purification steps using
salt precipitation, SDS-PAGE and FPLC. Similar seroreactivity was observed by the antigen isolated by both the methods in
indirect ELISA. Affinity chromatography helped in an increased recovery of ESAS-7F antigen and obviates the need for time
consuming conventional purification steps. 相似文献
150.
提出用铂工作电极安培检测器离子色谱法测定水和污水中微量肼的方法,试验了离子色谱仪的操作条件,包括淋洗液的浓度和流量、安培检测器的最佳施加电位,以及样品溶液酸度和干扰元素对测定的影响等.本方法测定的相对标准偏差低于10%,回收率在90%~95%,最低检出浓度为0.005mg/L.测定一个样品仅需5min. 相似文献