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254SMo奥氏体不锈钢的焊接 总被引:1,自引:0,他引:1
介绍了从瑞典进口的254SMo不锈钢板及其作为复层的复合钢板焊接工艺,并对如何保证焊接质量进行了阐述,该工艺经实践检验切实可行。 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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A method of determination for 93Zr/92Zr ratio by multi-collector inductively plasma mass spectrometry (MC-ICP-MS) was described in this paper. A 93Zr/92Zr ratio of (2.75±0.07)×10-5 was obtained in the original sample for AMS measurement and its relative standard error was 2.5%. Considered the contribute of above-thermal neutron, a calculated 93Zr/92Zr ratio of 2.56×10-5 was obtained and it was according with measurement of the result. The results showed that it can be used for AMS measurement standards sample preparation. A series 93Zr standards sample for AMS measurement were diluted by irradiated sample with enriched 92Zr. 相似文献
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采用DPPH法、ABTS法测定绶草不同有机溶剂萃取物的体外抗氧化活性,并用福林酚法测定其总酚含量。结果表明:绶草各溶剂萃取物均有明显的体外抗氧化活性,且呈剂量依赖性;各溶剂萃取物的抗氧化活性强弱及总酚含量大小顺序均为:乙酸乙酯萃取物正丁醇萃取物石油醚萃取物。说明绶草不同萃取物体外抗氧化活性与总酚含量呈正相关,其中乙酸乙酯萃取物的清除DPPH·及ABTS~+·的IC_(50)值分别为(45.270±0.005),(75.420±0.015)μg/mL,总酚含量为(13.861±0.002)%。 相似文献
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对挤压油膜阻尼器(SFD)在深孔加工中的应用进行了理论分析,采用短轴承近似按油膜理论求解了刀杆SFD的挤压油膜压力分布,按照达朗贝尔原理建立了刀杆轴颈 的运动微分方程,并在高精度内圆磨床上进行了磨削实验,实验表明SFD对磨床刀杆具有优良的减振性能。 相似文献
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高压共轨柴油机高海拔(低气压)燃烧特性 总被引:5,自引:0,他引:5
利用内燃机高原环境模拟试验台,对经过高海拔标定后的高压共轨柴油机进行了外特性试验,重点研究了高原环境条件(0~5,km)对低速和高速燃烧特性的影响.结果表明:该柴油机在低速下平均指示压力、最高燃烧压力、最大压力升高率和放热率峰值均随海拔的增加而减小;海拔每升高1,km,上述燃烧参数分别平均降低6.83%、7.03%、4.00%和3.92%.低速下最高燃烧压力点、放热率峰值点和放热率重心随海拔基本保持不变,最大压力升高率点后移.高速下平均指示压力和放热率峰值随海拔的增加而减小,海拔每升高1,km,分别降低2.59%和2.00%;最高燃烧压力随海拔基本保持不变,最高燃烧温度随海拔的增加而增高;最高燃烧压力点、最高燃烧温度点和放热率峰值点以及放热率重心前移.在高海拔高速工况下发生了燃烧压力振荡,造成噪声和机械负荷增大. 相似文献