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采用外加电流对混凝土构件中钢筋快速锈蚀,通过材性试验探讨了锈蚀钢筋力学性能,通过锈蚀钢筋混凝土构件荷载试验,探讨了钢筋锈蚀程度对混凝土构件的承载力、刚度的影响,有效地评估了锈蚀钢筋混凝土构件承载力的降低程度和耐久性。 相似文献
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Mass discrimination mostly is an obstacle to accurate determination of inductively coupled plasma mass spectrometry (ICP-MS). It is the prevailing notion that mass bias in ICP-MS results from space-charge effects of high density ions form the behind of skimmer cone to the before of slot where a fraction of lighter isotopes fail to enter the mass analyzer. Neodymium isotopes was analyzed by a Nu Plasma multi-collector inductively coupled plasma mass spectrometer (MC-ICP-MS) to investigate the mass discrimination, respectively changing two crucial analytical parameters: the nebulizer flow and the x-coordinate of inductively coupled plasma, measuring the variety of the Ar40Ar40 molecular ions intensity and the exponential factor of mass discrimination. The curves indicate the presence of the secondly mechanism that lead to the heavier isotope depletion. It is maybe the plasma centrifuge effects, a concept proposed firstly by Qing-zhu Yin and Cin-Ty Lee. The two contrary mechanisms act on the ions and in theory the points should be exist where the two forces are equilibrium and the measurement results are the expectation values. 相似文献
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软土地层地下连续墙成槽护壁泥浆研究 总被引:1,自引:0,他引:1
含砂性土等软土地层地下连续墙成槽施工,基槽侧壁易扰动坍塌,影响地下连续墙施工质量。降低泥浆失水量、适当提高泥浆粘度和防塌是护壁成槽的关键。结合宁波轨道交通车站基坑地下连续墙成槽施工,采用部分水解聚丙烯酰胺(PHP)、聚丙烯腈钙(CPAN)和硝基腐植酸钾(NKHm)作为添加剂,根据正交试验测定泥浆性能优化配比。研究表明:PHP失水量小,泥皮薄;CPAN和NKHm对降失水量效果明显,粘度适中。将试验结果应用于工程实践,护壁效果好。 相似文献
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在环境分析及地球化学研究等工作中,有时需要对低浓度的稀有气体氪(Kr)和氙(Xe)进行定量分析.常用的分析仪器是气相色谱(GC)和专用气体质谱计.专用气体质谱计在对样品进行预处理后可达到很高的同位素比值分析精度,但是直接进样测定低浓度氪和氙样品浓度值的精度较低,价格昂贵、应用范围较窄.GC测量简单快速、仪器价格便宜,但是只能测定氪和氙的浓度,无法分析同位素丰度,而且检测限相对较高,难以胜任低于ppm浓度氪和氙样品定量分析的要求.电感耦合等离子体质谱计(ICP-MS)作为一种理想的多元素快速分析仪器,一般认为其不适合稀有气体分析.本文简要介绍本实验室发展的应用ICP-MS测定低浓度Kr和Xe的技术. 相似文献