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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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属性约简是粗糙集理论一项重要的应用,目前已广泛运用于机器学习和数据挖掘等领域,邻域粗糙集是粗糙集理论中处理连续型数据的一种重要方法.针对目前邻域粗糙集模型中属性约简存在的缺陷,构造一种基于邻域粗糙集的邻域粗糙熵模型,并基于此给出邻域粗糙联合熵、邻域粗糙条件熵和邻域粗糙互信息熵等概念.邻域粗糙互信息熵是评估属性集相关性的一种重要的方法,具有非单调性变化的特性,对此,提出一种基于邻域粗糙互信息熵的非单调性属性约简算法.实验分析表明,所提出算法不仅比目前已有的单调性属性约简算法具有更优越的属性约简结果,而且具有更高的约简效率. 相似文献