Hamamatsu R1924A is one of the most widely used photomultiplier tubes(PMTs) in nuclear physics.Since the active base suitable for R1924A is still not available in market, an active base is designed for Hamamatsu R1924...Hamamatsu R1924A is one of the most widely used photomultiplier tubes(PMTs) in nuclear physics.Since the active base suitable for R1924A is still not available in market, an active base is designed for Hamamatsu R1924A PMT, and the test results at high counting rates are presented. The active bases with two different sets of resistor chains were tested and compared by a frequency-controlled green straw hat LED light. A stable signal output up to 100 kHz is achieved using frequency-controlled LED pulsed light. The temperature of bases, which reflects the power consumption and is crucial for applications in vacuum, is also monitored with the same LED pulsed light. The temperature of the active base with smaller resistances reaches about twice of that of the active base with larger resistances in the resistor chain. For the applications in vacuum, the active base with resistance between the two sets of resistor chains may be preferable.展开更多
Abstract： A new low-cost seismic isolation system based on spring tube bracings has been proposed and studied at the Structural and Earthquake Engineering Laboratory of Istanbul Technical University. Multiple compres...Abstract： A new low-cost seismic isolation system based on spring tube bracings has been proposed and studied at the Structural and Earthquake Engineering Laboratory of Istanbul Technical University. Multiple compression-type springs are positioned in a special cylindrical tube to obtain a symmetrical response in tension and compression-type axial loading. An isolation floor, which consists of pin-ended steel columns and spring tube bracings, is constructed at the foundation level or any intermediate level of the building. An experimental campaign with three stages was completed to evaluate the capability of the system. First, the behavior of the spring tubes subjected to axial displacement reversals with varying frequencies was determined. In the second phase, the isolation floor was assessed in the quasi-static tests. Finally, a scaled 3D steel frame was tested on the shake table using actual acceleration records. The transmitted acceleration to the floor levels is greatly diminished because of the isolation story, which effects longer period and higher damping. There are no stability and self- centering problems in the isolation floor.展开更多
Affected by external environmental factors and evolution of dam performance, dam seepage behavior shows nonlinear time-varying characteristics. In this study, to predict and evaluate the long-term development trend an...Affected by external environmental factors and evolution of dam performance, dam seepage behavior shows nonlinear time-varying characteristics. In this study, to predict and evaluate the long-term development trend and short-term fluctuation of the dam seepage behavior, two monitoring models were developed, one for the base flow effect and one for daily variation of dam seepage elements. In the first model, to avoid the influence of the time lag effect on the evaluation of seepage variation with the time effect component of seepage elements, the base values of the seepage element and the reservoir water level were extracted using the wavelet multi-resolution analysis method, and the time effect component was separated by the established base flow effect monitoring model. For the development of the daily variation monitoring model for dam seepage elements, all the previous factors, of which the measured time series prior to the dam seepage element monitoring time may have certain influence on the monitored results, were considered. Those factors that were positively correlated with the analyzed seepage element were initially considered to be the support vector machine(SVM) model input factors, and then the SVM kernel function-based sensitivity analysis was performed to optimize the input factor set and establish the optimized daily variation SVM model. The efficiency and rationality of the two models were verified by case studies of the water level of two piezometric tubes buried under the slope of a concrete gravity dam.Sensitivity analysis of the optimized SVM model shows that the influences of the daily variation of the upstream reservoir water level and rainfall on the daily variation of piezometric tube water level are processes subject to normal distribution.展开更多
The sulfide stress corrosion cracking（ SSC） performance of G3 and 028 nickel-based alloys w as studied using slow strain rate test（ SSRT） and the four-point bend（ FPB） test under simulated dow nhole conditions. ...The sulfide stress corrosion cracking（ SSC） performance of G3 and 028 nickel-based alloys w as studied using slow strain rate test（ SSRT） and the four-point bend（ FPB） test under simulated dow nhole conditions. The effect of high temperature,high H2 S / CO2 partial pressure,and the presence of sulfur on SSC susceptibility w as investigated. The G3 alloy w as found to have a higher SSC resistance than the 028 alloy. Presence of sulfur and temperature bear a strong influence on the SSC performance of the metals,particularly on the 028 alloy. The applicability of 028 and G3 alloys may be expanded and both could safely be used beyond the limits set by the ISO15156-3 standard.展开更多
The corrosion behavior of coatings of pure zinc and Zn-Al,Zn-Al-RE alloys in NaCl solu- tions was studied by salt-spray experiments,even corrosion experiments and electrochemical measurements of bi-directional polariz...The corrosion behavior of coatings of pure zinc and Zn-Al,Zn-Al-RE alloys in NaCl solu- tions was studied by salt-spray experiments,even corrosion experiments and electrochemical measurements of bi-directional polarization curves and a.c.impedance in weak polarization region consistent regularities were obtained by these different methods,viz.,the corrosion resistance of Zn could be enhanced by alloying it with Al,and particularly with Al-RE.The causes of enhancement of corrosion resistance by RE were also discussed.展开更多
目的检索、评价并整合国内外新生儿肠内营养胃管留置管理的相关证据。方法系统检索英国医学杂志最佳临床实践网、Up To Date、CINAHL、加拿大医学会临床实践指南网、国际指南网、WHO指南网、美国国立指南库、医脉通、Cochrane图书馆、Pu...目的检索、评价并整合国内外新生儿肠内营养胃管留置管理的相关证据。方法系统检索英国医学杂志最佳临床实践网、Up To Date、CINAHL、加拿大医学会临床实践指南网、国际指南网、WHO指南网、美国国立指南库、医脉通、Cochrane图书馆、PubMed、中国知网、中国生物医学文献数据库、万方数据库、维普等数据库等网站和数据库中关于新生儿肠内营养胃管留置管理的临床决策、推荐实践、证据总结、临床实践指南、技术报告、专家共识、系统评价,由2名研究者独立进行方法学质量评价后,根据主题对证据进行提取与汇总,检索时限为建库至2023年5月。结果共纳入14篇文献,包括指南2篇、证据总结1篇、系统评价5篇、专家共识3篇、最佳实践2篇、随机对照研究1篇。最后总结包括适应与禁忌、置管前的准备与评估、胃管位置验证、胃管固定、胃管维护5个方面的22条证据。结论本研究通过系统检索国内外高级别的循证资源,对新生儿肠内营养胃管留置的管理进行证据总结,所总结的新生儿肠内营养胃管留置管理证据全面、实用,可为规范新生儿胃管留置管理管理提供循证依据,保证新生儿肠内营养安全,提高新生儿护理质量。展开更多
基金supported by the National Natural Science Foundation of China(Nos.91426301 and 11075189)the Strategic Priority Research Program of the Chinese Academy of Sciences"ADS project"(No.XDA03030200)+2 种基金the Program for the CAS"Light of West China"(No.29Y601030)the US Department of Energy(No.DE-FG02-93ER40773)the program of the"visiting professorship of senior international scientists of the Chinese Academy of Sciences"for their support during his stay at the IMP
文摘Hamamatsu R1924A is one of the most widely used photomultiplier tubes(PMTs) in nuclear physics.Since the active base suitable for R1924A is still not available in market, an active base is designed for Hamamatsu R1924A PMT, and the test results at high counting rates are presented. The active bases with two different sets of resistor chains were tested and compared by a frequency-controlled green straw hat LED light. A stable signal output up to 100 kHz is achieved using frequency-controlled LED pulsed light. The temperature of bases, which reflects the power consumption and is crucial for applications in vacuum, is also monitored with the same LED pulsed light. The temperature of the active base with smaller resistances reaches about twice of that of the active base with larger resistances in the resistor chain. For the applications in vacuum, the active base with resistance between the two sets of resistor chains may be preferable.
基金Research Project 36997 of Istanbul Technical University Research Funds
文摘Abstract： A new low-cost seismic isolation system based on spring tube bracings has been proposed and studied at the Structural and Earthquake Engineering Laboratory of Istanbul Technical University. Multiple compression-type springs are positioned in a special cylindrical tube to obtain a symmetrical response in tension and compression-type axial loading. An isolation floor, which consists of pin-ended steel columns and spring tube bracings, is constructed at the foundation level or any intermediate level of the building. An experimental campaign with three stages was completed to evaluate the capability of the system. First, the behavior of the spring tubes subjected to axial displacement reversals with varying frequencies was determined. In the second phase, the isolation floor was assessed in the quasi-static tests. Finally, a scaled 3D steel frame was tested on the shake table using actual acceleration records. The transmitted acceleration to the floor levels is greatly diminished because of the isolation story, which effects longer period and higher damping. There are no stability and self- centering problems in the isolation floor.
基金supported by the National Natural Science Foundation of China(Grant No.51709021)the Open Foundation of the State Key Laboratory of Hydrology-Water Resources and Hydraulic Engineering(Grant No.2016491111)
文摘Affected by external environmental factors and evolution of dam performance, dam seepage behavior shows nonlinear time-varying characteristics. In this study, to predict and evaluate the long-term development trend and short-term fluctuation of the dam seepage behavior, two monitoring models were developed, one for the base flow effect and one for daily variation of dam seepage elements. In the first model, to avoid the influence of the time lag effect on the evaluation of seepage variation with the time effect component of seepage elements, the base values of the seepage element and the reservoir water level were extracted using the wavelet multi-resolution analysis method, and the time effect component was separated by the established base flow effect monitoring model. For the development of the daily variation monitoring model for dam seepage elements, all the previous factors, of which the measured time series prior to the dam seepage element monitoring time may have certain influence on the monitored results, were considered. Those factors that were positively correlated with the analyzed seepage element were initially considered to be the support vector machine(SVM) model input factors, and then the SVM kernel function-based sensitivity analysis was performed to optimize the input factor set and establish the optimized daily variation SVM model. The efficiency and rationality of the two models were verified by case studies of the water level of two piezometric tubes buried under the slope of a concrete gravity dam.Sensitivity analysis of the optimized SVM model shows that the influences of the daily variation of the upstream reservoir water level and rainfall on the daily variation of piezometric tube water level are processes subject to normal distribution.
文摘The sulfide stress corrosion cracking（ SSC） performance of G3 and 028 nickel-based alloys w as studied using slow strain rate test（ SSRT） and the four-point bend（ FPB） test under simulated dow nhole conditions. The effect of high temperature,high H2 S / CO2 partial pressure,and the presence of sulfur on SSC susceptibility w as investigated. The G3 alloy w as found to have a higher SSC resistance than the 028 alloy. Presence of sulfur and temperature bear a strong influence on the SSC performance of the metals,particularly on the 028 alloy. The applicability of 028 and G3 alloys may be expanded and both could safely be used beyond the limits set by the ISO15156-3 standard.
文摘The corrosion behavior of coatings of pure zinc and Zn-Al,Zn-Al-RE alloys in NaCl solu- tions was studied by salt-spray experiments,even corrosion experiments and electrochemical measurements of bi-directional polarization curves and a.c.impedance in weak polarization region consistent regularities were obtained by these different methods,viz.,the corrosion resistance of Zn could be enhanced by alloying it with Al,and particularly with Al-RE.The causes of enhancement of corrosion resistance by RE were also discussed.
文摘目的检索、评价并整合国内外新生儿肠内营养胃管留置管理的相关证据。方法系统检索英国医学杂志最佳临床实践网、Up To Date、CINAHL、加拿大医学会临床实践指南网、国际指南网、WHO指南网、美国国立指南库、医脉通、Cochrane图书馆、PubMed、中国知网、中国生物医学文献数据库、万方数据库、维普等数据库等网站和数据库中关于新生儿肠内营养胃管留置管理的临床决策、推荐实践、证据总结、临床实践指南、技术报告、专家共识、系统评价,由2名研究者独立进行方法学质量评价后,根据主题对证据进行提取与汇总,检索时限为建库至2023年5月。结果共纳入14篇文献,包括指南2篇、证据总结1篇、系统评价5篇、专家共识3篇、最佳实践2篇、随机对照研究1篇。最后总结包括适应与禁忌、置管前的准备与评估、胃管位置验证、胃管固定、胃管维护5个方面的22条证据。结论本研究通过系统检索国内外高级别的循证资源,对新生儿肠内营养胃管留置的管理进行证据总结,所总结的新生儿肠内营养胃管留置管理证据全面、实用,可为规范新生儿胃管留置管理管理提供循证依据,保证新生儿肠内营养安全,提高新生儿护理质量。
