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Insights and reviews on battery lifetime prediction from research to practice 被引量:1
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作者 Xudong Qu Dapai Shi +5 位作者 Jingyuan Zhao Manh-Kien Tran Zhenghong Wang Michael Fowler Yubo Lian Andrew FBurke 《Journal of Energy Chemistry》 SCIE EI CAS CSCD 2024年第7期716-739,共24页
The rising demand for energy storage solutions,especially in the electric vehicle and renewable energy sectors,highlights the importance of accurately predicting battery health to enhance their longevity and reliabili... The rising demand for energy storage solutions,especially in the electric vehicle and renewable energy sectors,highlights the importance of accurately predicting battery health to enhance their longevity and reliability.This article comprehensively examines various methods used to forecast battery health,including physics-based models,empirical models,and equivalent circuit models,among others.It delves into the promise of data-driven prognostics,utilizing both conventional machine learning and cuttingedge deep neural network techniques.The advantages and limitations of hybrid models are thoroughly analyzed,with a focus on the benefits of integrating diverse data sources to improve prognostic precision.Through practical case studies,the article showcases the effectiveness and flexibility of these approaches.It also critically addresses the challenges encountered in applying battery health prognostics in realworld scenarios,such as issues of scalability,complexity,and data anomalies.Despite these challenges,the article underscores the emerging opportunities brought about by recent technological,academic,and research advancements.These include the development of digital twin models for batteries,the use of data-centric AI and standardized benchmarking,the potential integration of blockchain technology for enhanced data security and transparency,and the synergy between edge and cloud computing to boost data analysis and processing.The primary goal of this article is to enrich the understanding of current battery health prognostic techniques and to inspire further research aimed at overcoming existing hurdles and tapping into new opportunities.It concludes with a visionary perspective on future research directions and potential developments in this evolving field,encouraging both researchers and practitioners to explore innovative solutions. 展开更多
关键词 Batteries lifetime HEALTH Machine learning Deep learning Field Real world
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Fully relativistic energies,transition properties,and lifetimes of lithium-like germanium
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作者 Shuang Li Jing Zhou +2 位作者 Liu-Hong Zhu Xiu-Fei Mei Jun Yan 《Chinese Physics B》 SCIE EI CAS CSCD 2024年第10期52-61,共10页
Employing two fully relativistic methods,the multi-reference configuration Dirac-Hartree-Fock(MCDHF)methodand the relativistic many-body perturbation theory(RMBPT)method,we report energies and lifetime values for the ... Employing two fully relativistic methods,the multi-reference configuration Dirac-Hartree-Fock(MCDHF)methodand the relativistic many-body perturbation theory(RMBPT)method,we report energies and lifetime values for the lowest35 energy levels of the(1s^(2))nl configurations(where the principal quantum number n=2-6 and the angular quantum numberl=0,...,n-1)of lithium-like germanium(Ge XXX),as well as complete data on the transition wavelengths,radiativerates,absorption oscillator strengths,and line strengths between the levels.Both the allowed(E1)and forbidden(magneticdipole M1,magnetic quadrupole M2,and electric quadrupole E2)ones are reported.The results from the two methodsare consistent with each other and align well with previous accurate experimental and theoretical findings.We assess theoverall accuracies of present RMBPT results to be likely the most precise ones to date.The present fully relativistic resultsshould be helpful for soft x-ray laser research,spectral line identification,plasma modeling and diagnosing.The datasetspresented in this paper are openly available at https://doi.org/10.57760/sciencedb.j00113.00135. 展开更多
关键词 MULTI-REFERENCE Dirac-Hartree-Fock relativistic many-body perturbation radiative rate lifetime
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Gross Alpha and Beta Activities and Related Lifetime Risks Assessment Due to Ingestion of Drinking Water from Different Sources in the District of Abidjan, Cote d’Ivoire
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作者 Ponaho Claude Kezo Issa Konate Dabo Salif Ignace Agba 《World Journal of Nuclear Science and Technology》 CAS 2024年第1期86-96,共11页
Drinking good quality water is essential for better health. It is therefore essential to assess the radiological quality of all water consumed in the District of Abidjan in order to prevent related hazards. Thus, the ... Drinking good quality water is essential for better health. It is therefore essential to assess the radiological quality of all water consumed in the District of Abidjan in order to prevent related hazards. Thus, the objective of this study was to assess the risk of cancer due to the ingestion of alpha and beta emitting radionuclides in the different types of water consumed in the region. A total of 63 water samples with 43 tap water samples, 5 bottled mineral water and 15 sachet water samples was collected and taken to GAEC laboratory for analysis. The low background Gas-less Automatic Alpha/Beta counting system (Canberra iMatic<sup>TM</sup>) was used to determine alpha and beta activity concentrations. Activity concentrations of both gross alpha and gross beta obtained in water sample were respectively lower than the WHO recommended limits of 0.1 Bq/l and 1 Bq/l. Also, the annual effective dose and total equivalent effective dose found in mineral bottled water samples were higher than in other types of water. The assessment of radiological lifetime risk has shown values of cancer risk due to ingestion alpha and beta emitters lower than recommended limit. These results indicate that there is no health hazard associated to consumption of water in the District of Abidjan. 展开更多
关键词 Gross Alpha and Beta Activities Drinking Water Effective Dose Radiological lifetime Risks
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Omni-Channel Retailing and Firm Performance from a Customer Lifetime Value Perspective
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作者 Liu Xiangdong Mi Zhuang He Mingqin 《China Economist》 2024年第3期89-103,共15页
In the digital era,retailers are keen to find out whether omni-channel retailing helps improve long-term firm performance.In this paper,we employ machine learning techniques on a large consumption data set in order to... In the digital era,retailers are keen to find out whether omni-channel retailing helps improve long-term firm performance.In this paper,we employ machine learning techniques on a large consumption data set in order to measure customer lifetime value(CLV)as the basis for determining long-term firm performance,and we provide an empirical analysis of the relationship between omni-channel retailing and CLV.The results suggest that omni-channel retailing may effectively enhance CLV.Further analysis reveals that this process is influenced by heterogeneous consumer requirements and that significant differences exist in the extent to which the omni-channel transition may influence CLV depending on consumer preferences for diversity of commodities,sensitivity to the cost of contract performance,and sensitivity to warehousing costs.Hence,retailers should provide consumers with a complete portfolio of goods and services based on target consumers’heterogeneous requirements in order to increase omni-channel efficiency. 展开更多
关键词 Omni-channel retailing customer lifetime value machine learning heterogeneous consumer requirements
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Stochastic Ranking Improved Teaching-Learning and Adaptive Grasshopper Optimization Algorithm-Based Clustering Scheme for Augmenting Network Lifetime in WSNs
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作者 N Tamilarasan SB Lenin +1 位作者 P Mukunthan NC Sendhilkumar 《China Communications》 SCIE CSCD 2024年第9期159-178,共20页
In Wireless Sensor Networks(WSNs),Clustering process is widely utilized for increasing the lifespan with sustained energy stability during data transmission.Several clustering protocols were devised for extending netw... In Wireless Sensor Networks(WSNs),Clustering process is widely utilized for increasing the lifespan with sustained energy stability during data transmission.Several clustering protocols were devised for extending network lifetime,but most of them failed in handling the problem of fixed clustering,static rounds,and inadequate Cluster Head(CH)selection criteria which consumes more energy.In this paper,Stochastic Ranking Improved Teaching-Learning and Adaptive Grasshopper Optimization Algorithm(SRITL-AGOA)-based Clustering Scheme for energy stabilization and extending network lifespan.This SRITL-AGOA selected CH depending on the weightage of factors such as node mobility degree,neighbour's density distance to sink,single-hop or multihop communication and Residual Energy(RE)that directly influences the energy consumption of sensor nodes.In specific,Grasshopper Optimization Algorithm(GOA)is improved through tangent-based nonlinear strategy for enhancing the ability of global optimization.On the other hand,stochastic ranking and violation constraint handling strategies are embedded into Teaching-Learning-based Optimization Algorithm(TLOA)for improving its exploitation tendencies.Then,SR and VCH improved TLOA is embedded into the exploitation phase of AGOA for selecting better CH by maintaining better balance amid exploration and exploitation.Simulation results confirmed that the proposed SRITL-AGOA improved throughput by 21.86%,network stability by 18.94%,load balancing by 16.14%with minimized energy depletion by19.21%,compared to the competitive CH selection approaches. 展开更多
关键词 Adaptive Grasshopper Optimization Algorithm(AGOA) Cluster Head(CH) network lifetime Teaching-Learning-based Optimization Algorithm(TLOA) Wireless Sensor Networks(WSNs)
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Numerical and Experimental Study of Localized Lifetime Control LIGBT by High Dose He Ion Implantation 被引量:3
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作者 方健 唐新伟 +1 位作者 李肇基 张波 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2004年第9期1048-1054,共7页
A high speed LIGBT with localized lifetime control by using high dose and low en ergy helium implantation(LC-LIGBT) is proposed.Compared with conventional LIGB Ts,particle irradiation results show that trade-off relat... A high speed LIGBT with localized lifetime control by using high dose and low en ergy helium implantation(LC-LIGBT) is proposed.Compared with conventional LIGB Ts,particle irradiation results show that trade-off relationship between turn- off time and forward voltage drop is improved.At the same time,the forward volta ge drop and turn-off time of such device are researched,when localized lifetime control region place near the p+-n junction,even in p+ anode.The results s how for the first time,helium ions,which stop in the p+ anode,also contribute to the forward voltage drop increasing and turn-off time reducing. 展开更多
关键词 LIGBT localized lifetime control helium ion implantation
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One Method for Fast Gate Oxide TDDB Lifetime Prediction 被引量:1
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作者 赵毅 万星拱 徐向明 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2005年第12期2271-2274,共4页
A method for fast gate oxide TDDB lifetime prediction for process control monitors (PCM) is proposed. For normal TDDB lifetime prediction at operation voltage and temperature, we must ge(three lifetimes at relative... A method for fast gate oxide TDDB lifetime prediction for process control monitors (PCM) is proposed. For normal TDDB lifetime prediction at operation voltage and temperature, we must ge(three lifetimes at relative low stress voltages and operation temperature. Then we use these three lifetimes to project the TDDB lifetime at operation voltage and temperature via the E-model. This requires a very long time for measurement. With our new method,it can be calculated quickly by projecting the TDDB lifetime at operation voltage and temperature with measurement data at relatively high stress voltages. Our test case indicates that this method is very effective. And the result with our new method is very close to that with the normal TDDB lifetime prediction method. But the measurement time is less than 50s for one sample,less than 1/100000 of that with the normal prediction method. With this new method,we can monitor gate oxide TDDB lifetime on-line. 展开更多
关键词 TDDB lifetime PREDICTION
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The NBEE and NWEE classes of lifetime distributions and their properties
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作者 王冠军 《Journal of Southeast University(English Edition)》 EI CAS 2012年第2期251-255,共5页
A class of lifetime distributions, new better than equilibrium in expectation (NBEE), and its dual, new worse than equilibrium in expectation (NWEE), are studied based on the comparison of the expectations of life... A class of lifetime distributions, new better than equilibrium in expectation (NBEE), and its dual, new worse than equilibrium in expectation (NWEE), are studied based on the comparison of the expectations of lifetime X and its equilibrium Xo. The relationships of the NBEE (NWEE) and other lifetime distribution classes are discussed. It is proved that the NBEE is very large, and increasing failure rate (IFR), new better than used (NBU) and the L class are its subclasses. The closure properties under two kinds of reliability operations, namely, convolution and mixture, are investigated. Furthermore, a Poisson shock model and a special cumulative model are also studied, in which the necessary and sufficient conditions for the NBEE (NWEE) lifetime distribution of the systems are established. In the homogenous Poisson shock model, the system lifetime belongs to NBEE(NWEE) if and only if the corresponding discrete failure distribution belongs to the discrete NBEE(NWEE). While in the cumulative model, the system has an NBEE lifetime if and only if the stochastic threshold of accumulated damage is NBEE. 展开更多
关键词 lifetime distribution survival function closure property new better than equilibrium in expectation (NBEE) equilibrium distribution shock model cumulative damage model
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Probabilistic Lifetime Assessment of Marine Reinforced Concrete with Steel Corrosion and Cover Cracking 被引量:10
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作者 陆春华 金伟良 刘荣桂 《China Ocean Engineering》 SCIE EI 2011年第2期305-318,共14页
In order to study the durability behavior of marine reinforced concrete structure suffering from chloride attack, the structural service life is assumed to be divided into three critical stages, which can be character... In order to study the durability behavior of marine reinforced concrete structure suffering from chloride attack, the structural service life is assumed to be divided into three critical stages, which can be characterized by steel corrosion and cover cracking. For each stage, a calculated model used to predict the lifetime is developed. Based on the definition of durability limit state, a probabilistic lifetime model and its time-dependent reliability analytical method are proposed considering the random natures of influencing factors. Then, the probabilistic lifetime prediction models are applied to a bridge pier located in the Hangzhou Bay with Monte Carlo simulation. It is found that the time to corrosion initiation to follows a lognormal distribution, while that the time from corrosion initiation to cover cracking t~ and the time for crack to develop from hairline crack to a limit crack width t2 can be described by Weibull distributions. With the permitted failure probability of 5.0%, it is also observed that the structural durability lifetime mainly depends on the durability life to and that the percentage of participation of the life to to the total service life grows from 61.5% to 83.6% when the cover thickness increases from 40 mm to 80 mm. Therefore, for any part of the marine RC bridge, the lifetime predictions and maintenance efforts should also be directed toward controlling the stage of corrosion initiation induced by chloride ion. 展开更多
关键词 marine reinforced concrete chloride ingress steel corrosion cover cracking probabilistic lifetime
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Fluid-structure Interaction Analysis and Lifetime Estimation of a Natural Gas Pipeline Centrifugal Compressor under Near-choke and Near-surge Conditions 被引量:12
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作者 JU Yaping LIU Hui +2 位作者 YAO Ziyun XING Peng ZHANG Chuhua 《Chinese Journal of Mechanical Engineering》 SCIE EI CAS CSCD 2015年第6期1261-1268,共8页
Up to present, there have been no studies concerning the application of fluid-structure interaction(FSI) analysis to the lifetime estimation of multi-stage centrifugal compressors under dangerous unsteady aerodynami... Up to present, there have been no studies concerning the application of fluid-structure interaction(FSI) analysis to the lifetime estimation of multi-stage centrifugal compressors under dangerous unsteady aerodynamic excitations. In this paper, computational fluid dynamics(CFD) simulations of a three-stage natural gas pipeline centrifugal compressor are performed under near-choke and near-surge conditions, and the unsteady aerodynamic pressure acting on impeller blades are obtained. Then computational structural dynamics(CSD) analysis is conducted through a one-way coupling FSI model to predict alternating stresses in impeller blades. Finally, the compressor lifetime is estimated using the nominal stress approach. The FSI results show that the impellers of latter stages suffer larger fluctuation stresses but smaller mean stresses than those at preceding stages under near-choke and near-surge conditions. The most dangerous position in the compressor is found to be located near the leading edge of the last-stage impeller blade. Compressor lifetime estimation shows that the investigated compressor can run up to 102.7 h under the near-choke condition and 200.2 h under the near-surge condition. This study is expected to provide a scientific guidance for the operation safety of natural gas pipeline centrifugal compressors. 展开更多
关键词 three-stage pipeline centrifugal compressor natural gas aerodynamic performance structural durability lifetime estimation CHOKE SURGE
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Room-temperature continuous-wave operation of GaN-based blue-violet laser diodes with a lifetime longer than 1000h 被引量:5
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作者 Feng Liang Jing Yang +9 位作者 Degang Zhao Zongshun Liu Jianjun Zhu Ping Chen Desheng Jiang Yongsheng Shi Hai Wang Lihong Duan Liqun Zhang Hui Yang 《Journal of Semiconductors》 EI CAS CSCD 2019年第2期39-42,共4页
GaN-based continuous-wave operated blue-violet laser diodes(LDs) with long lifetime are demonstrated, which are grown on a c-plane GaN substrate by metal organic chemical vapor deposition with a 10 × 600 μm^2 ri... GaN-based continuous-wave operated blue-violet laser diodes(LDs) with long lifetime are demonstrated, which are grown on a c-plane GaN substrate by metal organic chemical vapor deposition with a 10 × 600 μm^2 ridge waveguide structure.The electrical and optical characteristics of a blue-violet LD are investigated under direct-current injection at room temperature(25 °C). The stimulated emission wavelength and peak optical power of the LD are around 413 nm and over 600 mW, respectively.In addition, the threshold current density and voltage are as small as 1.46 kA/cm^2 and 4.1 V, respectively. Moreover, the lifetime is longer than 1000 hours under room-temperature continuous-wave operation. 展开更多
关键词 GAN-BASED blue-violet laser DIODES long lifetime threshold voltage
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The Application of Neural Network in Lifetime Prediction of Concrete 被引量:7
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作者 钟珞 《Journal of Wuhan University of Technology(Materials Science)》 SCIE EI CAS 2002年第1期79-81,共3页
There are many difficulties in concrete endurance prediction, especially in accurate predicting service life of concrete engineering. It is determined by the concentration of S042-/ Mg2+ / Cl- /Ca2+ , reactionareas , ... There are many difficulties in concrete endurance prediction, especially in accurate predicting service life of concrete engineering. It is determined by the concentration of S042-/ Mg2+ / Cl- /Ca2+ , reactionareas , the cycles of freezing and dissolving, alternatives of dry and wet state, the kind of cement, etc. . In general , because of complexity itself and cognitive limitation, endurance prediction under sulphate erosion is still illegible and uncertain, so this paper adopts neural network technology to research this problem. Through analyzing , the paper sets up a 3 - levels neural network and a 4 - levels neural network to predict the endurance undersulphate erosion. The 3 - levels neural network includes 13 inputting nodes, 7 outputting nodes and 34 hidden nodes. The 4 - levels neural network also has 13 inputting nodes and 7 outputting nodes with two hidden levels which has 1 nodes and 8 nodes separately. In the end the paper give a example with laboratorial data and discussion the result and deviation. The paper shows that deviation results from some faults of training specimens; such as few training specimens and few distinctions among training specimens. So the more specimens should be collected to reduce data redundancy and improve the reliability of network analysis conclusion. 展开更多
关键词 neural network concrete structure lifetime prediction
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Residual lifetime prediction model of nonlinear accelerated degradation data with measurement error 被引量:12
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作者 Zhongyi Cai Yunxiang Chen +1 位作者 Qiang Zhang Huachun Xiang 《Journal of Systems Engineering and Electronics》 SCIE EI CSCD 2017年第5期1028-1038,共11页
For the product degradation process with random effect (RE), measurement error (ME) and nonlinearity in step-stress accelerated degradation test (SSADT), the nonlinear Wiener based degradation model with RE and ME is ... For the product degradation process with random effect (RE), measurement error (ME) and nonlinearity in step-stress accelerated degradation test (SSADT), the nonlinear Wiener based degradation model with RE and ME is built. An analytical approximation to the probability density function (PDF) of the product's lifetime is derived in a closed form. The process and data of SSADT are analyzed to obtain the relation model of the observed data under each accelerated stress. The likelihood function for the population-based observed data is constructed. The population-based model parameters and its random coefficient prior values are estimated. According to the newly observed data of the target product in SSADT, an analytical approximation to the PDF of its residual lifetime (RL) is derived in accordance with its individual degradation characteristics. The parameter updating method based on Bayesian inference is applied to obtain the posterior value of random coefficient of the RL model. A numerical example by simulation is analyzed to verify the accuracy and advantage of the proposed model. 展开更多
关键词 accelerated degradation test residual lifetime (RL) prediction measurement error random effect NONLINEARITY
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Lifetime Prolonging Algorithms for Underwater Sensor Networks 被引量:5
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作者 郭忠文 李之伟 于磊 《China Ocean Engineering》 SCIE EI 2006年第2期325-334,共10页
Underwater acoustic modem technology has attained a level of maturity to support underwater acoustic sensor networks (UASNs) which are generally formed by acoustically connected sensor nodes and a surface station pr... Underwater acoustic modem technology has attained a level of maturity to support underwater acoustic sensor networks (UASNs) which are generally formed by acoustically connected sensor nodes and a surface station providing a link to an on-shore control center. While many applications require long-term monitoring of the deployment area, the batterypowered network nodes limit the lifetime of UASNs. Therefore, designing a UASN that minimizes the power consumption while maximizing lifetime becomes a very difficult task. In this paper, a method is proposed to determine the optimum number of clnstens throngh combining an application-specific protocol architecture and underwater acoustic communication model so as to reduce the energy dissipation of UASNs. Deploying more sensor nodes which work alternately is another way to prolong the lifetime of UASNs, An algorithm is presented for selecting sensor nodes and putting them into operation in each round, ensuring the monitoring to the whole given area. The present results show that the algorithm can help prolong system lifetime remarkably when it is applied to other conventional approaches for sensor networks under the condition that the sensor node density is high. 展开更多
关键词 lifetime acoustic networks underwater sensor networks TELEMETRY
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Touschek lifetime study based on the precise bunch-by-bunch BCM system at SSRF 被引量:2
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作者 Fang-Zhou Chen Zhi-Chu Chen +4 位作者 Yi-Mei Zhou Ning Zhang Bo Gao Xing-Yi Xu Yong-Bin Leng 《Nuclear Science and Techniques》 SCIE CAS CSCD 2019年第9期126-133,共8页
Continuous tracking of bunch charges is the key to maintain stable operations in a storage ring in top-up mode. Recently, a precise bunch-by-bunch beam-current measurement (BCM) system has been developed at the Shangh... Continuous tracking of bunch charges is the key to maintain stable operations in a storage ring in top-up mode. Recently, a precise bunch-by-bunch beam-current measurement (BCM) system has been developed at the Shanghai Synchrotron Radiation Facility. To avoid the influence of longitudinal oscillation on the amplitudes of the sampling points, a method called two-point equilibrium sampling is introduced. The results, obtained during routine operation time, show that the relative resolution of the measurement of the bunch charges is better than 0.02%. With this high resolution, the new BCM system is able to monitor the bunch-by-bunch beam lifetime. By using the filling pattern information, the Touschek lifetime and the vacuum lifetime can also be calculated. In this paper, the principle of the new method and the experiments is presented in detail. 展开更多
关键词 Beam-current measurement Bunch-bybunch Touschek lifetime Vacuum lifetime SSRF
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Effects of Shot Peening Process on Thermal Cycling Lifetime of TBCs Prepared by EB-PVD 被引量:5
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作者 ZHOU Zhao-hui GONG Sheng-kai +3 位作者 LI He-fei XU Hui-bin ZHANG Chun-gang WANG Lu 《Chinese Journal of Aeronautics》 SCIE EI CAS CSCD 2007年第2期145-147,共3页
Conventional two-layered thermal barrier coatings (TBCs) are prepared by electron beam physical vapor deposition (EB-PVD) with ZrO2-8 wt% Y2O3 (8YSZ) as top coat and CoCrAlY as bond coat on disk-shaped Ni based ... Conventional two-layered thermal barrier coatings (TBCs) are prepared by electron beam physical vapor deposition (EB-PVD) with ZrO2-8 wt% Y2O3 (8YSZ) as top coat and CoCrAlY as bond coat on disk-shaped Ni based super-alloy. In this paper, three kinds of shot peening process with different lengths of operating time were adopted for bond coating. As a result, changes took place in its surface roughness and the surface micro-hardness. A thermal cycling test at 1 273 Kx55 rain and another at room temperature for 5 min were performed to study the effects of shot peening process on the thermal cycling lifetime of TBCs. It is found that a moderate shot peening process will be able to prolong the life time. The oxidation dynamic of the as-processed TBCs basically accords with the parabolic rule, and the oxidation test also attests to the spallation between YSZ and thermal growth oxide (TGO) responsible mainly for the failure of TBCs. 展开更多
关键词 thermal cycling lifetime shot peening thermal barrier coatings (TBCs)
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Study of the key factors affecting the triple grid lifetime of the LIPS-300 ion thruster 被引量:4
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作者 孙明明 王亮 +3 位作者 杨俊泰 温晓东 黄永杰 王蒙 《Plasma Science and Technology》 SCIE EI CAS CSCD 2018年第4期152-163,共12页
In order to ascertain the key factors affecting the lifetime of the triple grids in the LIPS-300 ion thruster,the thermal deformation,upstream ion density and component lifetime of the grids are simulated with finite ... In order to ascertain the key factors affecting the lifetime of the triple grids in the LIPS-300 ion thruster,the thermal deformation,upstream ion density and component lifetime of the grids are simulated with finite element analysis,fluid simulation and charged-particle tracing simulation methods on the basis of a 1500 h short lifetime test.The key factor affecting the lifetime of the triple grids in the LIPS-300 ion thruster is obtained and analyzed through the test results.The results show that ion sputtering erosion of the grids in 5 kW operation mode is greater than in the case of 3 kW.In 5 kW mode,the decelerator grid shows the most serious corrosion,the accelerator grid shows moderate corrosion,and the screen grid shows the least amount of corrosion.With the serious corrosion of the grids in 5 kW operation mode,the intercept current of the acceleration and deceleration grids increases substantially.Meanwhile,the cold gap between the accelerator grid and the screen grid decreases from 1 mm to 0.7 mm,while the cold gap between the accelerator grid and the decelerator grid increases from 1 mm to 1.25 mm after 1500 h of thruster operation.At equilibrium temperature with 5 k W power,the finite element method(FEM)simulation results show that the hot gap between the screen grid and the accelerator grid reduces to 0.2 mm.Accordingly,the hot gap between the accelerator grid and the decelerator grid increases to 1.5 mm.According to the fluid method,the plasma density simulated in most regions of the discharge chamber is 1?×?10;-8?×?10;m;.The upstream plasma density of the screen grid is in the range 6?×?10;-6?×?10;m;and displays a parabolic characteristic.The charged particle tracing simulation method results show that the ion beam current without the thermal deformation of triple grids has optimal perveance status.The ion sputtering rates of the accelerator grid hole and the decelerator hole are 5.5?×?10;kg s;and 4.28?×?10;kg s;,respectively,while after the thermal deformation of the triple grids,the ion beam current has over-perveance status.The ion sputtering rates of the accelerator grid hole and the decelerator hole are 1.41?×?10;kg s;and 4.1?×?10;kg s;,respectively.The anode current is a key factor for the triple grid lifetime in situations where the structural strength of the grids does not change with temperature variation.The average sputtering rates of the accelerator grid and the decelerator grid,which were measured during the 1500 h lifetime test in5 k W operating conditions,are 2.2?×?10;kg s;and 7.3?×?10;kg s;,respectively.These results are in accordance with the simulation,and the error comes mainly from the calculation distribution of the upstream plasma density of the grids. 展开更多
关键词 the triple grids lifetime ion thruster key factor
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Analysis of Numerical Simulation Results of LIPS-200 Lifetime Experiments 被引量:5
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作者 陈娟娟 张天平 +4 位作者 耿海 贾艳辉 孟伟 吴先明 孙安邦 《Plasma Science and Technology》 SCIE EI CAS CSCD 2016年第6期611-616,共6页
Accelerator grid structural and electron backstreaming failures are the most important factors affecting the ion thruster's lifetime.During the thruster's operation,Charge Exchange Xenon(CEX) ions are generated fr... Accelerator grid structural and electron backstreaming failures are the most important factors affecting the ion thruster's lifetime.During the thruster's operation,Charge Exchange Xenon(CEX) ions are generated from collisions between plasma and neutral atoms.Those CEX ions grid's barrel and wall frequently,which cause the failures of the grid system.In order to validate whether the 20 cm Lanzhou Ion Propulsion System(LIPS-200) satisfies China's communication satellite platform's application requirement for North-South Station Keeping(NSSK),this study analyzed the measured depth of the pit/groove on the accelerator grid's wall and aperture diameter's variation and estimated the operating lifetime of the ion thruster.Different from the previous method,in this paper,the experimental results after the 5500 h of accumulated operation of the LIPS-200 ion thruster are presented firstly.Then,based on these results,theoretical analysis and numerical calculations were firstly performed to predict the on-orbit lifetime of LIPS-200.The results obtained were more accurate to calculate the reliability and analyze the failure modes of the ion thruster.The results indicated that the predicted lifetime of LIPS-200's was about 13218.1 h which could satisfy the required lifetime requirement of 11000 h very well. 展开更多
关键词 LIPS-200 ion thruster accelerator grid structural failure electron backstreaming failure lifetime
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A new analytical model for thermal stresses in multi-phase materials and lifetime prediction methods 被引量:3
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作者 Ladislav Ceniga 《Acta Mechanica Sinica》 SCIE EI CAS CSCD 2008年第2期189-206,共18页
Based on the fundamental equations of the mechanics of solid continuum, the paper employs an analytical model for determination of elastic thermal stresses in isotropic continuum represented by periodically distribute... Based on the fundamental equations of the mechanics of solid continuum, the paper employs an analytical model for determination of elastic thermal stresses in isotropic continuum represented by periodically distributed spherical particles with different distributions in an infinite matrix, imaginarily divided into identical cells with dimensions equal to inter-particle distances, containing a central spherical particle with or without a spherical envelope on the particle surface. Consequently, the multi-particle-(envelope)- matrix system, as a model system regarding the analytical modelling, is applicable to four types of multi-phase materials. As functions of the particle volume fraction v, the inter-particle distances dl, d2, d3 along three mutually per- pendicular axes, and the particle and envelope radii, R1 and R2, respectively, the thermal stresses within the cell, are originated during a cooling process as a consequence of the difference in thermal expansion coefficients of phases rep- resented by the matrix, envelope and particle. Analytical-(experimental)-computational lifetime prediction methods for multi-phase materials are proposed, which can be used in engineering with appropriate values of parameters of real multi-phase materials. 展开更多
关键词 Thermal stress Multi-phase material lifetime prediction Analytical modelling
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Thermal decomposition kinetics and lifetime of the complex of Tb_2(BA)_6(PHEN)_2 被引量:2
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作者 ZHANGJianjun WANGRuifen +3 位作者 WANGShuping LIUHongmei LIJibiao BAIJihai 《Rare Metals》 SCIE EI CAS CSCD 2004年第2期126-130,共5页
The thermal behavior of Tb_2(BA)_6(PHEN)_2 (BA: benzoate, and PHEN:1,10-phenanthroline) in a static air atmosphere was investigated by TG-DTG, SEM and IR techniques.By the kinetic method of processing thermal analysis... The thermal behavior of Tb_2(BA)_6(PHEN)_2 (BA: benzoate, and PHEN:1,10-phenanthroline) in a static air atmosphere was investigated by TG-DTG, SEM and IR techniques.By the kinetic method of processing thermal analysis data put forward by Malek et al., it is definedthat the kinetic model for the first-step thermal decomposition is SB(m, n). The activation energyE for this step reaction is 99.07 kJ/mol, the entropy of activation ΔS~≠ is -84.72 J/mol, theenthalpy of activation ΔH~≠ is 94.26 kJ/mol, the free energy of activation ΔG~≠ is 144.77 kJ/moland the pre-exponential factor lnA is 20.93. The lifetime equation at mass-loss of 10% was deducedas lnτ = -29.0312 + 19760.83/T by isothermal thermogravimetric analysis. 展开更多
关键词 lifetime KINETICS benzoic acid terbium complex thermal decomposition
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