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HIRFL-CSR上全剥离同核异能态离子的寿命测量
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作者 曾奇 李小燕 +3 位作者 刘义保 张怀强 赵剑锟 李宏福 《东华理工大学学报(自然科学版)》 CAS 北大核心 2024年第5期474-481,共8页
高电荷态离子的寿命数据被广泛应用于核物理及核天体物理等多个研究领域,在核废料处理等应用领域具有潜在应用价值。在兰州重离子加速器装置(HIRFL-CSR)上建立了一套基于等时性质量谱仪测量全剥离同核异能态离子寿命的实验方法。该实验... 高电荷态离子的寿命数据被广泛应用于核物理及核天体物理等多个研究领域,在核废料处理等应用领域具有潜在应用价值。在兰州重离子加速器装置(HIRFL-CSR)上建立了一套基于等时性质量谱仪测量全剥离同核异能态离子寿命的实验方法。该实验方法在测量几十微秒到几百微秒时间尺度上发生的核衰变具有独特优势,尤其适用于开展全剥离同核异能态离子的衰变研究。飞行时间探测器记录离子的时间信号,通过这些时间信号可提取出每个离子的飞行时间信息并得到飞行时间与循环圈数的直线拟合残差。直线拟合残差就可以来鉴别衰变事件,基于衰变事件可得到全剥离同核异能态离子^(94)m Ru^(44+)的寿命。实验证明了基于储存环开展短寿命高电荷同核异能态离子衰变研究的可行性。 展开更多
关键词 兰州重离子加速器 等时性质量谱仪 全剥离离子 寿命核素寿命 94m Ru
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长寿命电气二次设备的加速试验方法 被引量:6
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作者 梁经宛 刘志远 +3 位作者 姜帅 牛强 席亚克 杜军 《电测与仪表》 北大核心 2014年第10期39-44,共6页
以继电保护装置为例对电气二次设备实际寿命进行了调研和分析,总结出目前影响电气二次设备寿命的主要因素、影响机理和相应的对策;重点以20年使用寿命为目标,利用影响因素结论构建了基于Weibull分布和Peck模型的应力-寿命加速试验方法,... 以继电保护装置为例对电气二次设备实际寿命进行了调研和分析,总结出目前影响电气二次设备寿命的主要因素、影响机理和相应的对策;重点以20年使用寿命为目标,利用影响因素结论构建了基于Weibull分布和Peck模型的应力-寿命加速试验方法,并根据贝尔实验室的推荐公式得出加速试验的基本参数。为验证电气二次设备寿命提供了试验的理论依据。 展开更多
关键词 寿命二次设备 应力一寿命加速寿命试验 WEIBULL分布 平均无故障时间
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提高电机复合模使用寿命的措施
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作者 甘立新 《机械工人(热加工)》 1994年第8期15-17,共3页
定、转子是电机的主要零部件之一。电机定、转子硅钢片槽形孔加工是影响电机生产的重要环节。为了提高生产效率,在冲床吨位足够的情况下,一般采用复合模冲制硅钢片槽形孔。然而复合模成本高,制造周期长,因此,复合模使用寿命直接影响到... 定、转子是电机的主要零部件之一。电机定、转子硅钢片槽形孔加工是影响电机生产的重要环节。为了提高生产效率,在冲床吨位足够的情况下,一般采用复合模冲制硅钢片槽形孔。然而复合模成本高,制造周期长,因此,复合模使用寿命直接影响到生产。 1.复合模的使用寿命 (1)复合模使用寿命是指冲压出所定质量范围内的产品件数,包括冲模修磨后的冲压件数。所定质量一般是指所允许的产品毛刺高度。 展开更多
关键词 电机 复合模 寿命寿命 定子 转子
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圆管在承受交变载荷时的裂纹扩展寿命分析
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作者 王芝斌 熊丁根 王伟伟 《建筑机械》 2019年第9期43-46,共4页
起重机结构设计中,常常使用圆管结构作为重要的疲劳受力构件,其结构又往往设有应力释放孔,以方便结构制作。本文使用断裂力学的方法,对此结构的裂纹扩展寿命及裂纹的扩展速度进行了详细分析。
关键词 起重机 管结构 裂纹扩展寿命寿命 裂纹扩展速度 断裂力学
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Fatigue behavior and life prediction of A7N01 aluminium alloy welded joint 被引量:7
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作者 刘雪松 张亮 +2 位作者 王林森 吴双辉 方洪渊 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2012年第12期2930-2936,共7页
Fatigue characteristics of A7N01 aluminium alloy welded joint were investigated and a fatigue crack initiation life-based model was proposed. The difference of fatigue crack initiation life among base metal, weld meta... Fatigue characteristics of A7N01 aluminium alloy welded joint were investigated and a fatigue crack initiation life-based model was proposed. The difference of fatigue crack initiation life among base metal, weld metal and heat affected zone (HAZ) is slight. Furthermore, the ratio of fatigue crack initiation life (Ni) to fatigue life to failure(Nf) is a material dependent parameter, 26.32%, 40.21% and 60.67% for base metal, HAZ and weld metal, respectively. Total fatigue life predicted using the presented model is in good agreement with the experimental data and that using Basquin’s model. The observation results of fatigue fracture surfaces, using scanning electron microscope (SEM), demonstrate that fatigue crack initiates from smooth surface due to welding process for weld metal, blowhole in HAZ causes fatigue crack initiation, and the crushed second phase particles play an important part in fatigue crack initiation in base metal. 展开更多
关键词 aluminium alloy A7N01 aluminum alloy welded joint crack initiation FATIGUE fatigue life life prediction
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Vacuum interrupter,high reliability component of distribution switches,circuit breakers and contactors 被引量:4
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作者 SLADE Paul G. MAYO Stephen +1 位作者 SMITH R.Kirkland TAYLOR Erik D. 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2007年第3期335-342,共8页
The use of vacuum interrupters(VIs)as the current interruption component for switches,circuit breakers,reclosers and contactors operating at distribution voltages has escalated since their introduction in the mid-1950... The use of vacuum interrupters(VIs)as the current interruption component for switches,circuit breakers,reclosers and contactors operating at distribution voltages has escalated since their introduction in the mid-1950’s.This electrical product has developed a dominating position for switching and protecting distribution circuits.VIs are even being introduced into switching products operating at transmission voltages.Among the reasons for the VI’s popularity are its compactness,its range of application,its low cost,its superb electrical and mechanical life and its ease of application.Its major advantage is its well-established reliability.In this paper we show how this reliability has been achieved by design,by mechanical life testing and by electrical performance testing.We introduce the“sealed for life”concept for the VI’s integrity.We discuss this in terms of what is meant by a practical leak rate for VIs with a life of over 30 years.We show that a simple high voltage withstand test is an easy and effective method for monitoring the long-term vacuum integrity.Finally we evaluate the need for routine inspection of this electrical product when it is used in adverse ambient environments. 展开更多
关键词 Vacuum interrupter (VI) RELIABILITY Mechanical life Electrical life
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Remaining useful life estimation based on Wiener degradation processes with random failure threshold 被引量:15
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作者 TANG Sheng-jin YU Chuan-qiang +3 位作者 FENG Yong-bao XIE Jian GAO Qin-he SI Xiao-sheng 《Journal of Central South University》 SCIE EI CAS CSCD 2016年第9期2230-2241,共12页
Remaining useful life(RUL) estimation based on condition monitoring data is central to condition based maintenance(CBM). In the current methods about the Wiener process based RUL estimation, the randomness of the fail... Remaining useful life(RUL) estimation based on condition monitoring data is central to condition based maintenance(CBM). In the current methods about the Wiener process based RUL estimation, the randomness of the failure threshold has not been studied thoroughly. In this work, by using the truncated normal distribution to model random failure threshold(RFT), an analytical and closed-form RUL distribution based on the current observed data was derived considering the posterior distribution of the drift parameter. Then, the Bayesian method was used to update the prior estimation of failure threshold. To solve the uncertainty of the censored in situ data of failure threshold, the expectation maximization(EM) algorithm is used to calculate the posteriori estimation of failure threshold. Numerical examples show that considering the randomness of the failure threshold and updating the prior information of RFT could improve the accuracy of real time RUL estimation. 展开更多
关键词 condition based maintenance remaining useful life wiener process random failure threshold BAYESIAN EM algorithm
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Bayesian framework for satellite rechargeable lithium battery synthesizing bivariate degradation and lifetime data 被引量:10
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作者 ZHANG Yang JIA Xiang GUO Bo 《Journal of Central South University》 SCIE EI CAS CSCD 2018年第2期418-431,共14页
Reliability and remaining useful life(RUL)estimation for a satellite rechargeable lithium battery(RLB)are significant for prognostic and health management(PHM).A novel Bayesian framework is proposed to do reliability ... Reliability and remaining useful life(RUL)estimation for a satellite rechargeable lithium battery(RLB)are significant for prognostic and health management(PHM).A novel Bayesian framework is proposed to do reliability analysis by synthesizing multisource data,including bivariate degradation data and lifetime data.Bivariate degradation means that there are two degraded performance characteristics leading to the failure of the system.First,linear Wiener process and Frank Copula function are used to model the dependent degradation processes of the RLB's temperature and discharge voltage.Next,the Bayesian method,in combination with Markov Chain Monte Carlo(MCMC)simulations,is provided to integrate limited bivariate degradation data with other congeneric RLBs'lifetime data.Then reliability evaluation and RUL prediction are carried out for PHM.A simulation study demonstrates that due to the data fusion,parameter estimations and predicted RUL obtained from our model are more precise than models only using degradation data or ignoring the dependency of different degradation processes.Finally,a practical case study of a satellite RLB verifies the usability of the model. 展开更多
关键词 rechargeable lithium battery Bayesian framework bivariate degradation lifetime data remaining useful life reliability evaluation
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Fatigue Life Assessment of Top Tensioned Risers Under Vortex-Induced Vibrations 被引量:11
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作者 LI Xiaomin GUO Haiyan MENG Fanshun 《Journal of Ocean University of China》 SCIE CAS 2010年第1期43-47,共5页
The fatigue life of top tensioned risers under vortex-induced vibrations (VIVs) with consideration of the effect of internal flowing fluid on the riser is analyzed in the time domain.The long-term stress histories of ... The fatigue life of top tensioned risers under vortex-induced vibrations (VIVs) with consideration of the effect of internal flowing fluid on the riser is analyzed in the time domain.The long-term stress histories of the riser under VIVs are calculated and the mean stresses,the number of stress cycles and amplitudes are determined by the rainflow counting method.The Palmgren-Miner rule for cumulative damage theory with a specified S-N curve is used to estimate the fatigue life of the riser.The corresponding numerical programs numerical simulation of vortex-induced vibrations (NSVIV) which can be used to calculate the VIV response and fatigue life of the riser are compiled.Finally the influences of the riser's parameters such as flexural rigidity,top tension and internal flow velocity on the fatigue life of the riser are analyzed in detail and some conclusions are drawn. 展开更多
关键词 top tensioned riser (TTR) internal flow vortex-induced vibration (VIV) fatigue life
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Real time remaining useful life prediction based on nonlinear Wiener based degradation processes with measurement errors 被引量:22
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作者 唐圣金 郭晓松 +3 位作者 于传强 周志杰 周召发 张邦成 《Journal of Central South University》 SCIE EI CAS 2014年第12期4509-4517,共9页
Real time remaining useful life(RUL) prediction based on condition monitoring is an essential part in condition based maintenance(CBM). In the current methods about the real time RUL prediction of the nonlinear degrad... Real time remaining useful life(RUL) prediction based on condition monitoring is an essential part in condition based maintenance(CBM). In the current methods about the real time RUL prediction of the nonlinear degradation process, the measurement error is not considered and forecasting uncertainty is large. Therefore, an approximate analytical RUL distribution in a closed-form of a nonlinear Wiener based degradation process with measurement errors was proposed. The maximum likelihood estimation approach was used to estimate the unknown fixed parameters in the proposed model. When the newly observed data are available, the random parameter is updated by the Bayesian method to make the estimation adapt to the item's individual characteristic and reduce the uncertainty of the estimation. The simulation results show that considering measurement errors in the degradation process can significantly improve the accuracy of real time RUL prediction. 展开更多
关键词 remaining useful life Wiener based degradation process measurement error nonlinear maximum likelihood estimation Bayesian method
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NAND flash service lifetime estimate with recovery effect and retention time relaxation 被引量:1
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作者 步凯 陈怡然 +2 位作者 徐晖 易伟 谢启友 《Journal of Central South University》 SCIE EI CAS 2014年第8期3205-3213,共9页
A service life model of NAND flash and threshold voltage shift process is proposed to calculate the service life and endurance.The relationships among achievable program/erase(P/E) cycles,recovery time,bad block rate ... A service life model of NAND flash and threshold voltage shift process is proposed to calculate the service life and endurance.The relationships among achievable program/erase(P/E) cycles,recovery time,bad block rate and storage time are analyzed.The achievable endurance and service life of a NAND flash are evaluated based on a flash cell degradation and recovery model by varying recovery time,badblock rate,and storage time.It is proposed to improve the service lifetime of solid state disk by both relaxing the bad block rate limitation and retention time while extending the recovery time.The results indicate that endurance can be improved by 17 times if the storage time guarantee is reduced from 10 a to 1 a with 105 s recovery time inserted between cycles. 展开更多
关键词 NAND flash ENDURANCE RETENTION recovery effect program/erase (P/E) cycle
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Longevity,Capital Formation and Economic Development 被引量:1
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作者 Zhang Qiong 1.School of Economics,Central University of Finance and Economics,Beijing 200084,China 2.School of Economics and Management,Tsinghua University,Beijing 100084 China 《Chinese Journal of Population,Resources and Environment》 2012年第1期53-63,共11页
Many researchers have concluded that longer life expectancies prompt increased investment in education,as a prolonged labor supply raises the rate of return on education.Besides explaining the empirical evidence behin... Many researchers have concluded that longer life expectancies prompt increased investment in education,as a prolonged labor supply raises the rate of return on education.Besides explaining the empirical evidence behind this conclusion(at an absolute level),there is another issue to be discussed:does time spent studying and working increase proportionally with higher longevity? Building on an extended life-cycle model,this paper shows that prolonged life expectancy will cause individuals to increase their time in education but may not warrant rises in labor input.Later we show that higher improvement rate of longevity rather than initial life expectancy will promote economic growth,even we exclude the mechanism of human capital formation,and only consider growth effects of higher improvement rate of life expectancy from physical capital investment. 展开更多
关键词 LONGEVITY EDUCATION labor supply economic development
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Quality-Oriented Facade Systems: Initial Investments vs. Global Cost Approach
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作者 Rachele Perego 《Journal of Civil Engineering and Architecture》 2016年第4期483-491,共9页
An analysis applied to an existing building considering the whole service life, regulated or, if any, measured, of energy/technological upgrading action does not only require initial investments to be taken into accou... An analysis applied to an existing building considering the whole service life, regulated or, if any, measured, of energy/technological upgrading action does not only require initial investments to be taken into account. Of course, such investments are significant and will have to be considered at a first stage, but it is not the only aspect to be considered. Provisions of Construction Procurement Guidance, No.7 Whole Life Costs state: "All procurement must be made solely on the basis of value for money in terms of the optimum combination of global costs--and not only initial investment costs--and quality to meet the user's requirements". 展开更多
关键词 Facade system initial investments global cost approach QUALITY convenience.
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Issues of an Ageing Population in European Union
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作者 Peter Cajka 《Journal of Environmental Science and Engineering(B)》 2012年第8期966-970,共5页
One of the main contemporary problems requiring urgent attention since its present and future repercussions on particular countries is the decrease of population and related problems of population ageing. The populati... One of the main contemporary problems requiring urgent attention since its present and future repercussions on particular countries is the decrease of population and related problems of population ageing. The population ageing is not a worldwide problem yet, it concerns mostly world developed countries. On the other hand, it is a known fact that the population ageing in developing countries will culminate in few decades and will be more dramatic as the current population ageing in the developed world. In the developed countries, the population ageing is cause by the prolonged human life and the decrease of natality. This trend is resulting from many factors that are related to the modernization of the society which caused the decrease in fertility and natality. The health care improvement resulted in the prolonged life expectancy and a better health condition of the population. The science advance prolonged the average life expectancy which is the main reason for the population ageing. 展开更多
关键词 Ageing population PENSION demographic growth/decline.
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Remaining Useful Life Prediction of Li-Po Batteries in UAVs Using Extended Kalman Filter 被引量:1
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作者 Darielson A. Souza Joao L. O. Tortes +3 位作者 Joao Paulo P. Gomes Leonardo R. Rodrigues Romulo N. de C.Almeida Vandilberto P. Pinto 《Journal of Mechanics Engineering and Automation》 2015年第12期687-690,共4页
The use of batteries in UAVs (unmanned aerial vehicles) has become common due to some advantages in comparison with internal combustion engines such as weight reduction and better power control. However, in these ve... The use of batteries in UAVs (unmanned aerial vehicles) has become common due to some advantages in comparison with internal combustion engines such as weight reduction and better power control. However, in these vehicles it is critical to monitor the RUL (remaining useful life) of the batteries. This information can be used, for instance, as a decision support tool to define which missions could be assigned to the UAV until the next battery recharge. This work presents a methodology to predict the RUL of Li-Po (Lithium-Polymer) batteries. The approach uses an extended Kalman filter and an exponential model for the degradation evolution. The proposed methodology uses time series of battery terminal voltages, assuming that the discharge occurs under a constant current condition. Different discharge current levels were considered.The results showed that the proposed methodology provides good results, despite its simplicity. 展开更多
关键词 Extended Kalman filter Li-Po battery RUL estimation UAV.
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Investigating the Life-Span of Cork Products through a Longitudinal ApproachmOverview of Two Years Results
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作者 Ana Carina Pereira Helena Pereira 《Journal of Environmental Science and Engineering(B)》 2013年第7期436-441,共6页
Products with long life-spans are generally acknowledged to have a significant contribution towards sustainability. This paper provides an overview and discussion of the two years results of a longitudinal study perfo... Products with long life-spans are generally acknowledged to have a significant contribution towards sustainability. This paper provides an overview and discussion of the two years results of a longitudinal study performed with users and several cork products. The research aimed to tackle the process of life-span, and the results include: (1) the identification and interrelation of the aspects influencing the life-span of the products; (2) the evolution of life-span over time; and (3) new knowledge and guidelines arising about the material. Overall, most cork products are still being used, have a very good life-span, and most issues arising are material related. 展开更多
关键词 Product life-span USERS longitudinal study cork products and materials.
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Ultralong-life and high-rate web-like Li4Ti5O12 anode for high-performance flexible lithium-ion batteries 被引量:18
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作者 Xianfu Wang Bin Liu +4 位作者 Xiaojuan Hou Qiufan Wang Wenwu Li Di Chen Guozhen Shen 《Nano Research》 SCIE EI CAS CSCD 2014年第7期1073-1082,共10页
Flexible lithium ion batteries (LIBs) have recently attracted increasing attention as they show unique promising advantages, such as flexibility, shape diversity, and light weight. Similar to conventional LIBs, flex... Flexible lithium ion batteries (LIBs) have recently attracted increasing attention as they show unique promising advantages, such as flexibility, shape diversity, and light weight. Similar to conventional LIBs, flexible LIBs with long cycle life and high-rate performance are very important for applications of high performance flexible electronics. Herein, we report a three-dimensional (3D) web-like binderfree Li4Ti5O12 (LTO) anode assembled from numerous 1D nanowires exhibiting excellent cycling performance with high capacities of 153 and 115 mA·h·g^-1 after 5,000 cycles at 2 C and 20 C, respectively, and excellent rate property with a capacity of 103 mA·h·g^-1 even at a very high current rate of 80 C. Surprisingly, a flexible full battery assembled from the web-like LTO nanostructure and LiMn2O4 (LMO) nanorods exhibited a high capacity of 125 mA·h·g^-1 at high current rate of 20 C, and showed excellent flexibility with little performance degradation even in seriously bent states. 展开更多
关键词 ultralong-life high-rate web-like Li4Ti5O12 anode flexible batteries
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A TWO-STAGE ESTIMATION ALGORITHM FOR A TYPE OF CURRENT STATUS DATA
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作者 Hui ZHAO Ningning JIANG 《Journal of Systems Science & Complexity》 SCIE EI CSCD 2012年第3期556-566,共11页
Success-failure life tests are widely used in reliability engineering research to evaluate the storage life of products, where the observed data are the current status data, usually summarized as the form of "binomia... Success-failure life tests are widely used in reliability engineering research to evaluate the storage life of products, where the observed data are the current status data, usually summarized as the form of "binomial life data". For this type of data, this paper proposes a two-stage algorithm to estimate some commonly used lifetime distributions. This Mgorithm is automatic, intuitively appealing and simple to implement. Simulation studies show that compared with some existing methods, the proposed algorithm is more stable and efficient, especially in small sample situations, and it can also be extended to deM with some complicated lifetime distributions. 展开更多
关键词 Current status data nonparametric maximum likelihood estimation success-failure lifetest.
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