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结合深厚软土地区地基加固工程,通过钻芯试验和单桩(复合地基)静载荷试验研究钉形水泥搅拌桩的承载特性。钻芯试验表明,桩身水泥土强度随深度增加而逐渐减小,深部水泥土强度随龄期增长较明显。单桩(复合地基)静载荷试验研究表明,扩大头部分的桩身轴力衰减速度比桩身下部快,桩深10 m处轴力非常小。单桩复合地基静载荷试验的桩身轴力衰减速度更快,而复合地基桩土应力比随荷载的增大而逐渐减小并趋于稳定。 相似文献
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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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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
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