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压样机在γ核素样品制备过程中的应用
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作者 曾卫海 《中文科技期刊数据库(文摘版)工程技术》 2021年第2期299-300,共2页
环境监测样品多为粉末样或灰样,需要装入样品盒中才能测量。通常用的装样方法为人工压样法或震荡压样法,但两者都存在制备的样品与放射源介质体积或密度上有差异的缺陷,这将会引入测量误差。而用压样机压样可以有效避免这个问题,同时,... 环境监测样品多为粉末样或灰样,需要装入样品盒中才能测量。通常用的装样方法为人工压样法或震荡压样法,但两者都存在制备的样品与放射源介质体积或密度上有差异的缺陷,这将会引入测量误差。而用压样机压样可以有效避免这个问题,同时,经过高压压制后的样品由于样品体积减少,在部分情况下可以显著提高探测效率,降低探测限。 展开更多
关键词 环境监测 γ核素 压样机 制样 探测效率 误差
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Analysis and Prototyping of Multicellular DC-DC Transformer for Environmentally Friendly Data Centers
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作者 Yusuke Hayashi Tamotsu Ninomiya 《Journal of Energy and Power Engineering》 2016年第5期313-323,共11页
A multicellular DCX (dc-dc transformer) using unregulated cell converters has been proposed for the environmentally friendly data centers. The high speed cell converter with the switching frequency over MHz behaves ... A multicellular DCX (dc-dc transformer) using unregulated cell converters has been proposed for the environmentally friendly data centers. The high speed cell converter with the switching frequency over MHz behaves as an ideal transformer, and this behavior solves the voltage imbalance issue in the multicellular converter topology. The analysis of the unregulated cell converter is conducted by using the state space averaging method, and the operation condition for the ideal transformer is specified. The behavior of the multicellular DCX using the high speed cell converters has been also analyzed, and the voltage imbalance issue among cell converters is discussed quantitatively. A prototype of a 19.2 kW 384 V-384 V multicellular DCX using sixty-four unregulated cell converters is fabricated and the validity of the analyses is verified. 展开更多
关键词 DCX (dc-dc transformer) high frequency dc-dc converter ISOP (input series output parallel) IPOS (input parallel output series) state space averaging method.
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Triaxial mechanical creep behavior of sandstone 被引量:16
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作者 YANG Shengqi JIANG Yuzhou 《Mining Science and Technology》 EI CAS 2010年第3期339-349,共11页
Based on laboratory results of time-dependent mechanical behavior tests,we investigated short-term and mechanical creep behavior of sandstone,observed in conventional triaxial compression experiments at room temperatu... Based on laboratory results of time-dependent mechanical behavior tests,we investigated short-term and mechanical creep behavior of sandstone,observed in conventional triaxial compression experiments at room temperature,using a servo-controlled rheology testing machine.Given our short-term experimental test results,we confirmed deviatoric creep stress levels of sandstone.Multiple deviatoric stress levels were applied in steps to each sample.Each deviatoric stress level before the final failed deviatoric stress was maintained for 48 h or longer.Time-dependent variations of axial strains of sandstone samples are discussed and evaluated.During the creep tests,complete tertiary creep curves of sandstone were observed under failed deviatoric stress levels with different confining pressures.Slices of coal in sandstone samples can lead to distinct tertiary creep deformation failure. 展开更多
关键词 SANDSTONE CREEP experimental investigation tertiary creep creep failure
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Dynamic simulation of hydrokinetic hammer based on virtual prototyping technology
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作者 WANG Siyi WANG Qingyan 《Global Geology》 2009年第1期22-27,共6页
This study presented the specified steps of comprehensively analyzing the hydraulic-driven hammer system with the application of the Virtual Prototype Technology.By comparing the simulation results with experimental p... This study presented the specified steps of comprehensively analyzing the hydraulic-driven hammer system with the application of the Virtual Prototype Technology.By comparing the simulation results with experimental phenomena and data,the correctness of simulation analysis conclusion is verified.Meanwhile,by means of its perfect visualization,the internal work process which can not be seen before is simulated.The mechanism of some abnormal phenomena encountered during the experiment is explained. 展开更多
关键词 Virtual Prototype hydraulic-driven hammer dynamic simulation
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