Rational planning of spares configuration project is an effective approach to improve equipment availability as well as reduce life cycle cost （LCC）. With an analysis of various impacts on support system, the spares...Rational planning of spares configuration project is an effective approach to improve equipment availability as well as reduce life cycle cost （LCC）. With an analysis of various impacts on support system, the spares demand rate forecast model is constructed. According to systemic analysis method, spares support effectiveness evaluation indicators system is built, and then, initial spares configuration and optimization method is researched. To the issue of discarding and con-sumption for incomplete repairable items, its expected backorders function is approximated by Laplace demand distribution. Combining the （s-1, s） and （R, Q） inventory policy, the spares resup-ply model is established under the batch ordering policy based on inventory state, and the optimi-zation analysis flow for spares configuration is proposed. Through application on shipborne equipment spares configuration, the given scenarios are analyzed under two constraint targets：one is the support effectiveness, and the other is the spares cost. Analysis reveals that the result is consistent with practical regulation;therefore, the model＇s correctness, method＇s validity as well as optimization project＇s rationality are proved to a certain extent.展开更多
为了了解电缆在长时间使用后的健康状况,通过对数正态分布和Weibull分布两种分布函数来进行电缆状态的评估。先假定电缆的介电损耗与局部放电数据符合两种分布,借助于Matlab数值模拟软件对某供电公司近几年通过振荡波试验检测积累的老...为了了解电缆在长时间使用后的健康状况,通过对数正态分布和Weibull分布两种分布函数来进行电缆状态的评估。先假定电缆的介电损耗与局部放电数据符合两种分布,借助于Matlab数值模拟软件对某供电公司近几年通过振荡波试验检测积累的老化数据进行了拟合,并对两种拟合结果进行了对比分析。结果证明,对数正态分布更符合电缆老化参数的分布。设定了电缆状态的三个级别,通过建立状态评估模型,并使用该模型完成对某供电公司10 k V电缆的状态评估。研究成果有助于及时了解电缆在运行过程中的状态变化,并提出对应的检修计划。展开更多
A robust partial-state feedback asymptotic regulating control scheme is developed for a class of cascade systems with both nonlinear uncertainties and unknown control directions. A parameter separation technique is in...A robust partial-state feedback asymptotic regulating control scheme is developed for a class of cascade systems with both nonlinear uncertainties and unknown control directions. A parameter separation technique is introduced to separate the time-varying uncertainty and the unmeasurable state from nonlinear functions. Then, the Nussbaum-type gain method together with the idea of changing supply functions is adopted in the design of a smooth partial-state regulator that can ensure all the signals of the closed-loop system are globally uniformly bounded. Especially, the system state asymptotically converges to zero. The design procedure is illustrated through an example and the simulation results show that the controller is feasible and effective.展开更多
The lead acid battery has been a dominant device in large-scale energy storage systems since its invention in 1859.It has been the most successful commercialized aqueous electrochemical energy storage system ever sinc...The lead acid battery has been a dominant device in large-scale energy storage systems since its invention in 1859.It has been the most successful commercialized aqueous electrochemical energy storage system ever since.In addition,this type of battery has witnessed the emergence and development of modern electricity-powered society.Nevertheless,lead acid batteries have technologically evolved since their invention.Over the past two decades,engineers and scientists have been exploring the applications of lead acid batteries in emerging devices such as hybrid electric vehicles and renewable energy storage;these applications necessitate operation under partial state of charge.Considerable endeavors have been devoted to the development of advanced carbon-enhanced lead acid battery(i.e.,lead-carbon battery)technologies.Achievements have been made in developing advanced lead-carbon negative electrodes.Additionally,there has been significant progress in developing commercially available lead-carbon battery products.Therefore,exploring a durable,long-life,corrosion-resistive lead dioxide positive electrode is of significance.In this review,the possible design strategies for advanced maintenance-free lead-carbon batteries and new rechargeable battery configurations based on lead acid battery technology are critically reviewed.Moreover,a synopsis of the lead-carbon battery is provided from the mechanism,additive manufacturing,electrode fabrication,and full cell evaluation to practical applications.展开更多
基金co-supported by the General Armament Department Pre-research Foundation of China (Nos. 51304010206, 51327 020105)
文摘Rational planning of spares configuration project is an effective approach to improve equipment availability as well as reduce life cycle cost （LCC）. With an analysis of various impacts on support system, the spares demand rate forecast model is constructed. According to systemic analysis method, spares support effectiveness evaluation indicators system is built, and then, initial spares configuration and optimization method is researched. To the issue of discarding and con-sumption for incomplete repairable items, its expected backorders function is approximated by Laplace demand distribution. Combining the （s-1, s） and （R, Q） inventory policy, the spares resup-ply model is established under the batch ordering policy based on inventory state, and the optimi-zation analysis flow for spares configuration is proposed. Through application on shipborne equipment spares configuration, the given scenarios are analyzed under two constraint targets：one is the support effectiveness, and the other is the spares cost. Analysis reveals that the result is consistent with practical regulation;therefore, the model＇s correctness, method＇s validity as well as optimization project＇s rationality are proved to a certain extent.
文摘为了了解电缆在长时间使用后的健康状况,通过对数正态分布和Weibull分布两种分布函数来进行电缆状态的评估。先假定电缆的介电损耗与局部放电数据符合两种分布,借助于Matlab数值模拟软件对某供电公司近几年通过振荡波试验检测积累的老化数据进行了拟合,并对两种拟合结果进行了对比分析。结果证明,对数正态分布更符合电缆老化参数的分布。设定了电缆状态的三个级别,通过建立状态评估模型,并使用该模型完成对某供电公司10 k V电缆的状态评估。研究成果有助于及时了解电缆在运行过程中的状态变化,并提出对应的检修计划。
基金supported by the National Natural Science Foundation of China (No.60774010,60574080)the research startup Foundation of Qufu Normal University
文摘A robust partial-state feedback asymptotic regulating control scheme is developed for a class of cascade systems with both nonlinear uncertainties and unknown control directions. A parameter separation technique is introduced to separate the time-varying uncertainty and the unmeasurable state from nonlinear functions. Then, the Nussbaum-type gain method together with the idea of changing supply functions is adopted in the design of a smooth partial-state regulator that can ensure all the signals of the closed-loop system are globally uniformly bounded. Especially, the system state asymptotically converges to zero. The design procedure is illustrated through an example and the simulation results show that the controller is feasible and effective.
基金support from the National Natural Science Foundation of China(Nos.22108044,21573093,21975101)the Science and Technology Innovation Team Project of Jilin University(No.2017TD-31)+5 种基金the National Natural Science Foundation of China(No.21706038)the National Natural Science Foundation of China(No.22038004)the Natural Science Foundation for Guangdong Province(No.2019B151502038)the National Key Research and Development Plan(No.2018YFB1501503)the Research and Development Program in Key Fields of Guangdong Province(2020B1111380002)the financial support from the Guangdong Provincial Key Laboratory of Plant Resources Biorefinery(2021GDKLPRB07).
文摘The lead acid battery has been a dominant device in large-scale energy storage systems since its invention in 1859.It has been the most successful commercialized aqueous electrochemical energy storage system ever since.In addition,this type of battery has witnessed the emergence and development of modern electricity-powered society.Nevertheless,lead acid batteries have technologically evolved since their invention.Over the past two decades,engineers and scientists have been exploring the applications of lead acid batteries in emerging devices such as hybrid electric vehicles and renewable energy storage;these applications necessitate operation under partial state of charge.Considerable endeavors have been devoted to the development of advanced carbon-enhanced lead acid battery(i.e.,lead-carbon battery)technologies.Achievements have been made in developing advanced lead-carbon negative electrodes.Additionally,there has been significant progress in developing commercially available lead-carbon battery products.Therefore,exploring a durable,long-life,corrosion-resistive lead dioxide positive electrode is of significance.In this review,the possible design strategies for advanced maintenance-free lead-carbon batteries and new rechargeable battery configurations based on lead acid battery technology are critically reviewed.Moreover,a synopsis of the lead-carbon battery is provided from the mechanism,additive manufacturing,electrode fabrication,and full cell evaluation to practical applications.
