排序方式: 共有88条查询结果,搜索用时 156 毫秒
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非水光度滴定法测定钢中低碳 总被引:2,自引:0,他引:2
严恒太 《理化检验(化学分册)》1998,34(8):339-341
研究了非水滴定定碳法中非水吸收液的组成、指示剂的配比及滴定终点时溶液色泽的吸光度变化。结果表明,由乙醇、乙醇胺及不饱和多胺组成的非水体系对钢样燃烧时所释出的二氧化碳能最有效的吸收。试验选择了百里酚酞和茜素黄R的混合液为滴定指示剂,能给出敏锐的终点指示。在此基础上设计了一套非水定碳的自动分析装置。无论自动仪器或手工操作所得的分析结果都与标准值符合。方法应用于低含量碳的测定。 相似文献
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GE HanQing LENG Yan ZHANG FuMin PIAO JiaRui ZHOU ChangJiang & WANG Jun State Key Laboratory of Materials-Oriented Chemical Engineering College of Chemistry Chemical Engineering Nanjing University of Technology Nanjing China Petrochemical Research Institute PetroChina Company Ltd. Beijing 《中国科学B辑(英文版)》2009,(8)
Pyridine(Py)-modified Keggin-type vanadium-substituted heteropoly acids(PynPMo10V2O40,n=1 to 5) were prepared by a precipitation method as organic/inorganic hybrid catalysts for direct hydroxylation of benzene to phenol in a pressured batch reactor and their structures were detected by FT-IR.Among various catalysts,Py3PMo10V2O40 exhibits the highest catalytic activity(yield of phenol,11.5%),without observing the formation of catechol,hydroquinone and benzoquinone in the reaction with 80 vol% aqueous acetic ... 相似文献
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SUN HuanQuan XIAO HongYan & LIU XinHou Institute of Geological Science Shengli Oilfield Ltd.Co. Dongying China Key Laboratory of Photochemical Conversion Optoelectronic Materials Technical Institute of Physics Chemistry Chinese Academy of Sciences Beijing China 《中国科学B辑(英文版)》2011,(7)
Molecular dynamics simulations have been performed to investigate the structural properties of hydroxyl-substituted alkyl benzenesulfonate monolayers formed at the water/vapor and water/decane interfaces.We report a detailed study of the interfacial properties—liquid density profile,hydrogen bond structure,surfactant aggregate structure and order parameter—of the novel anionic surfactant,sodium 2-hydroxy-3-decyl-5-octylbenzenesulfonate(C10C8OHphSO3Na).Simulation results show that:with increasing number of s... 相似文献
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建立快速溶解硅铁及其合金的试验方法,并利用电感耦合等离子体发射光谱仪分析检测硅铁及其合金中微量元素及痕量元素,证明了快速溶解法的可行性.结果显示,方法的精密度及检测仪器重复性测量不确定度的结果均符合国家标准规定的允许偏差范围,说明快速溶解法具有一定推广价值和应用前景. 相似文献
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无氧铜是超导线材的重要原料及组成部分,超导组元组装前对无氧铜表面质量的要求很高,表面状态要呈现无氧铜粉红色的本色,光亮、均一,无肉眼可见的油、酸痕、水痕等存在,又要严控杂质含量,除去吸附水等,因此研究无氧铜表面洁净化清洗工艺具有重要意义.工艺研究要立足于既能符合表面质量要求,又适应工业规模生产,同时工艺过程稳定.清洗工艺的工艺流程包括前处理化学去油、酸洗、水洗、烘干等主要环节.本文就硝酸配合表面活性剂及缓蚀剂、双氧水配合硝酸酸洗工艺方案进行了试验研究和对比分析,并就清洗工艺中的化学去油、酸洗、水洗、烘干各环节工艺过程控制及整体控制要求进行了试验研究与分析.研究结果表明:⑴化学去油的彻底、洁净,是保证酸洗质量、效率及最终表面质量的必要条件;⑵通过扫描电镜和光电子能谱分析不同酸洗方案后的表面状态,表面状态和元素含量及分布具有同一性;⑶最终表面质量不仅由化学去油及酸洗环节决定,酸洗环节后的水洗及烘干环节也是保证最终表面质量的重要方面;⑷酸洗环节转入水洗环节、水洗环节转入烘干环节的环境控制和时间间隔控制也是保证最终表面质量的重要方面;⑸工艺过程控制中无氧铜表面工况条件及工况条件变化的均一性,有利于最终良好表面质量的形... 相似文献
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高性能内锡法Nb3Sn超导股线可用于国际热核聚变反应堆(ITER)磁体,股线加工过程中的断线问题是股线制备的关键技术之一.在股线的Sn组元中添加适量的Ti不但能够提高Sn的强度利于股线的长线加工;同时Ti元素的添加还可以提高热处理中Nb3Sn的成相速度,降低晶粒尺寸,提高股线的电磁特性.本文介绍了满足Nb3Sn超导股线制备要求的Sn-Ti合金的制备技术,分析了不同浇铸温度对铸锭的影响,对比了加工中Sn-Ti合金的微观组织变化,为我们制备满足ITER要求的Nb3Sn超导股线提供了重要的保障. 相似文献
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<正>The square soft-edge diaphragm with round angle is designed by Matlab,and is sent to a liquid crystal spatial light modulator by the computer.In order to obtain precompensation for the following laser system, local diaphragm transmission can be adjusted by feedback signals of surface-channel charge-coupled device (SCCD).This method can reduce the diffraction effect and realize no modulation,high stability,high homogeneity,and large scale laser beam.Several parameters of soft-edge diaphragms which affect the laser beam quality are studied systematically,and the optimized values are obtained.The method can avoid the serious modulation of hard edges and provide soft-edge diaphragms of different shapes in a fast and convenient way for the large scale laser beam system. 相似文献
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ShanminGao LiPang HongweiChe XiaopingZhou 《中国颗粒学报》2004,2(4):177-181
Nanocrystalline SnO2 was synthesized by direct mixing and grinding of SnCI4-5H2O and NaOH at room temperature, followed by calcination at different temperatures for different times in air. Product samples were characterized by X-ray diffraction and transmission electron microscope, revealing that the amorphous precursor SnO2 was transformed to crystals at 200℃ for 3h, and that the average particle size increased upon raising the calcining temperature or prolonging the calcining time. The mechanism of the phase transformation of the products is discussed. 相似文献
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