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Insights and reviews on battery lifetime prediction from research to practice
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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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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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Topology Driven Cooperative Self Scheduling for Improved Lifetime Maximization in WSN 被引量:1
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作者 G.Brindha P.Ezhilarasi 《Computer Systems Science & Engineering》 SCIE EI 2023年第4期445-458,共14页
In Wireless Sensor Network(WSN),scheduling is one of the important issues that impacts the lifetime of entire WSN.Various scheduling schemes have been proposed earlier to increase the lifetime of the network.Still,the... In Wireless Sensor Network(WSN),scheduling is one of the important issues that impacts the lifetime of entire WSN.Various scheduling schemes have been proposed earlier to increase the lifetime of the network.Still,the results from such methods are compromised in terms of achieving high lifetime.With this objective to increase the lifetime of network,an Efficient Topology driven Cooperative Self-Scheduling(TDCSS)model is recommended in this study.Instead of scheduling the network nodes in a centralized manner,a combined approach is proposed.Based on the situation,the proposed TDCSS approach performs scheduling in both the ways.By sharing the node statistics in a periodic manner,the overhead during the transmission of control packets gets reduced.This in turn impacts the lifetime of all the nodes.Further,this also reduces the number of idle conditions of each sensor node which is required for every cycle.The proposed method enables every sensor to schedule its own conditions according to duty cycle and topology constraints.Central scheduler monitors the network conditions whereas total transmissions occurs at every cycle.According to this,the source can infer the possible routes in a cycle and approximate the available routes.Further,based on the statistics of previous transmissions,the routes towards the sink are identified.Among the routes found,a single optimal route with energy efficiency is selected to perform data transmission.This cooperative approach improves the lifetime of entire network with high throughput performance. 展开更多
关键词 WSN SELF-SCHEDULING TDCSS SCHEDULING lifetime maximization quality of service
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Impacts of hydrogen annealing on the carrier lifetimes in p-type 4H-SiC after thermal oxidation
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作者 张锐军 洪荣墩 +11 位作者 韩景瑞 丁雄杰 李锡光 蔡加法 陈厦平 傅德颐 林鼎渠 张明昆 吴少雄 张宇宁 吴正云 张峰 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第6期60-65,共6页
Thermal oxidation and hydrogen annealing were applied on a 100μm thick Al-doped p-type 4H-Si C epitaxial wafer to modulate the minority carrier lifetime,which was investigated by microwave photoconductive decay(μ-PC... Thermal oxidation and hydrogen annealing were applied on a 100μm thick Al-doped p-type 4H-Si C epitaxial wafer to modulate the minority carrier lifetime,which was investigated by microwave photoconductive decay(μ-PCD).The minority carrier lifetime decreased after each thermal oxidation.On the contrary,with the hydrogen annealing time increasing to3 hours,the minority carrier lifetime increased from 1.1μs(as-grown)to 3.14μs and then saturated after the annealing time reached 4 hours.The increase of surface roughness from 0.236 nm to 0.316 nm may also be one of the reasons for limiting the further improvement of the minority carrier lifetimes.Moreover,the whole wafer mappings of minority carrier lifetimes before and after hydrogen annealing were measured and discussed.The average minority carrier lifetime was up to 1.94μs and non-uniformity of carrier lifetime reached 38%after 4-hour hydrogen annealing.The increasing minority carrier lifetimes could be attributed to the double mechanisms of excess carbon atoms diffusion caused by selective etching of Si atoms and passivation of deep-level defects by hydrogen atoms. 展开更多
关键词 4H-SIC carrier lifetime hydrogen annealing
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Fully relativistic many-body perturbation energies,transition properties,and lifetimes of lithium-like iron Fe XXIV
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作者 李双 赵敏 +2 位作者 刘国庆 胡昌宝 潘国柱 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第10期90-99,共10页
Employing the advanced relativistic configuration interaction(RCI)combined with the many-body perturbation theory(RMBPT)method,we report energies and lifetime values for the lowest 35 energy levels from the(1s^(2))nl ... Employing the advanced relativistic configuration interaction(RCI)combined with the many-body perturbation theory(RMBPT)method,we report energies and lifetime values for the lowest 35 energy levels from the(1s^(2))nl configurations(where the principal quantum number n=2–6 and the angular quantum number l=0,...,n-1)of lithium-like iron Fe XXIV,as well as complete data on the transition wavelengths,radiative rates,absorption oscillator strengths,and line strengths between the levels.Both the allowed(E1)and forbidden(magnetic dipole M1,magnetic quadrupole M2,and electric quadrupole E2)ones are reported.Through detailed comparisons with previous results,we assess the overall accuracies of present RMBPT results to be likely the most precise ones to date.Configuration interaction effects are found to be very important for the energies and radiative properties for the ion.The present RMBPT results are valuable for spectral line identification,plasma modeling,and diagnosing. 展开更多
关键词 relativistic many-body perturbation multi-reference configuration radiative rates lifetime
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Lifetime measurement of the 3d^(9) ^(2)D_(3/2) metastable level in Mo^(15+)at an electron beam ion trap
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作者 刘佳林 王银涛 +7 位作者 屠秉晟 黄良玉 司然 李冀光 张明武 傅云清 邹亚明 姚科 《Chinese Physics B》 SCIE EI CAS CSCD 2023年第10期400-404,共5页
An experimental measurement of the lifetime of 3d^(9) ^(2)D_(3/2) metastable level in Mo^(15+)is reported in this work.The Mo^(15+)ions are produced and trapped in an electron beam ion trap with a magnetic field of 0.... An experimental measurement of the lifetime of 3d^(9) ^(2)D_(3/2) metastable level in Mo^(15+)is reported in this work.The Mo^(15+)ions are produced and trapped in an electron beam ion trap with a magnetic field of 0.65 T.The decay photons emitted from 3d^(9) ^(2)D_(3/2) level are subsequently recorded via a cooled photomultiplier tube.Through meticulous scrutiny of potential systematic uncertainties affecting the measurement outcomes,we have determined the lifetime of Mo^(15+)3d^(9)2D_(3/2)metastable level to be 2.83(22)ms.The experimental result provides a clear distinguishment from existing calculations based on various theoretical approaches. 展开更多
关键词 lifetime measurement molybdenum ions metastable levels electron beam ion trap(EBIT)
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Carbides Formation in MarM247 Directional Solidified during Stress-Rupture Test at High Temperature
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作者 Daniel Moreno Itzik Mizrahi +3 位作者 Yuri Lipkin Vasiliy Zevin Elinor Itzhak Zion Harush 《Journal of Minerals and Materials Characterization and Engineering》 2023年第5期131-142,共12页
In our study, stress-rupture tests were conducted at elevated temperatures to examine the impact of high temperature on MarM247 LC (low carbon). Our main objective was to investigate the alterations in the microstruct... In our study, stress-rupture tests were conducted at elevated temperatures to examine the impact of high temperature on MarM247 LC (low carbon). Our main objective was to investigate the alterations in the microstructure, particularly the carbon precipitation, during long-term stress-rupture tests. It was observed that cracks developed near the sample neck, following the path of the carbides and the gamma matrix, rather than occurring in the gamma-gamma prime eutectic. This occurred despite the formation of carbides because of prolonged exposure to high temperature and load, and the crack propagation did not follow that path. Based on these findings, we suggest that a reduction in the carbon content of Mar-M247 LC can enhance the sample's lifespan when subjected to temperatures below 760˚C and a stress of 690 MPa. 展开更多
关键词 MarM247 Carbides stress-rupture High-Temperature CRACK-PROPAGATION
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Exciton radiative lifetime in CdSe quantum dots
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作者 Zhimin Ji Zhigang Song 《Journal of Semiconductors》 EI CAS CSCD 2023年第3期104-113,共10页
Colloidal CdSe quantum dots(QDs)are promising materials for solar cells because of their simple preparation pro-cess and compatibility with flexible substrates.The QD radiative recombination lifetime has attracted eno... Colloidal CdSe quantum dots(QDs)are promising materials for solar cells because of their simple preparation pro-cess and compatibility with flexible substrates.The QD radiative recombination lifetime has attracted enormous attention as it affects the probability of photogenerated charges leaving the QDs and being collected at the battery electrodes.However,the scaling law for the exciton radiative lifetime in CdSe QDs is still a puzzle.This article presents a novel explanation that recon-ciles this controversy.Our calculations agree with the experimental measurements of all three divergent trends in a broadened energy window.Further,we proved that the exciton radiative lifetime is a consequence of the thermal average of decays for all thermally accessible exciton states.Each of the contradictory size-dependent patterns reflects this trend in a specific size range.As the optical band gap increases,the radiative lifetime decreases in larger QDs,increases in smaller QDs,and is weakly depend-ent on size in the intermediate energy region.This study addresses the inconsistencies in the scaling law of the exciton life-time and gives a unified interpretation over a widened framework.Moreover,it provides valuable guidance for carrier separa-tion in the thin film solar cell of CdSe QDs. 展开更多
关键词 solar cells CdSe quantum dot radiative lifetime scaling law optical band gap exciton fine structure room temperat-ure
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Room-Temperature Phosphorescence and Lifetime of Fossil Resins (Amber) from Dominican Republic, Mexico, Baltic Sea, Myanmar, and Fushun, China
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作者 Zhiqing Zhang Yamei Wang Andy H.Shen 《宝石和宝石学杂志(中英文)》 CAS 2023年第4期111-119,共9页
Amber can emit room temperature phosphorescence(RTP)under the well-known 365 nm fluorescence ultraviolet light.This paper is devoted to the phosphorescence study of 20 pieces of amber materials from the Dominican Repu... Amber can emit room temperature phosphorescence(RTP)under the well-known 365 nm fluorescence ultraviolet light.This paper is devoted to the phosphorescence study of 20 pieces of amber materials from the Dominican Republic,Mexico,Baltic sea,Myanmar,and Fushun,China.The results show that amber from the same geographic origin has similar shape in phosphorescence spectra.However,the shape of the amber phosphorescence spectra varies depending on their different localities.Burmite(amber from Myanmar)and Fushun amber have a bright yellow phosphorescence with a long lifetime,while the Dominican and Mexican ones are weaker and last shorter.The irradiation of Baltic amber becomes faint or even inert.Phosphorescence spectral Gaussian fitting results suggest an emission maximum near 550 nm in most amber samples.Their phosphorescence lifetime,analyzed through the exponential function fitting,is up to 1 second in Burmite and Fushun samples,shorter in the Dominican and Mexican ones,about 0.230 s,and the shortest in Baltic amber,close to 0.151 s.These variations of phosphorescence lifetime and intensity are related to the relative geological ages of these amber.It indicated that the phosphorescence agent was probably formed during the long geological time.While the anomaly occurred in Baltic amber,the only one found in a sea secondary deposit form,it demonstrated that the terrestrial geological environment these amber preserved has prevented the phosphorescence agent to be deactivated. 展开更多
关键词 ossil resin AMBER room-temperature phosphorescence(RTP) phosphorescence lifetime
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Outdoor Air Quality Monitoring with Enhanced Lifetime-enhancing Cooperative Data Gathering and Relaying Algorithm (E-LCDGRA) Based Sensor Network
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作者 G.Pius Agbulu G.Joselin Retnar Kumar 《Journal of Computer Science Research》 2023年第1期13-20,共8页
The air continues to be an extremely substantial part of survival on earth.Air pollution poses a critical risk to humans and the environment.Using sensor-based structures,we can get air pollutant data in real-time.How... The air continues to be an extremely substantial part of survival on earth.Air pollution poses a critical risk to humans and the environment.Using sensor-based structures,we can get air pollutant data in real-time.However,the sensors rely upon limited-battery sources that are immaterial to be alternated repeatedly amid extensive broadcast costs associated with real-time applications like air quality monitoring.Consequently,air quality sensor-based monitoring structures are lifetime-constrained and prone to the untimely loss of connectivity.Effective energy administration measures must therefore be implemented to handle the outlay of power dissipation.In this study,the authors propose outdoor air quality monitoring using a sensor network with an enhanced lifetime-enhancing cooperative data gathering and relaying algorithm(E-LCDGRA).LCDGRA is a cluster-based cooperative event-driven routing scheme with dedicated relay allocation mechanisms that tackle the problems of event-driven clustered WSNs with immobile gateways.The adapted variant,named E-LCDGRA,enhances the LCDGRA algorithm by incorporating a non-beacon-aided CSMA layer-2 un-slotted protocol with a back-off mechanism.The performance of the proposed E-LCDGRA is examined with other classical gathering schemes,including IEESEP and CERP,in terms of average lifetime,energy consumption,and delay. 展开更多
关键词 Air quality CLUSTER Delay Energy lifetime WSN
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Temperature dependence of anisotropic stress-rupture properties of nickel-based single crystal superalloy SRR99 被引量:9
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作者 韩国明 杨彦红 +1 位作者 于金江 孙晓峰 《Transactions of Nonferrous Metals Society of China》 SCIE EI CAS CSCD 2011年第8期1717-1721,共5页
In order to reveal the temperature dependence of anisotropic stress?rupture behavior of SRR99 single crystal superalloys under conditions of temperature ranging from 650 to 1 040 °C and typical stresses,fracture... In order to reveal the temperature dependence of anisotropic stress?rupture behavior of SRR99 single crystal superalloys under conditions of temperature ranging from 650 to 1 040 °C and typical stresses,fracture morphologies and microstructure evolution were investigated by SEM and TEM.From the Larson-Miller curves,it is found that single crystal with [001] orientation has the optimum stress rupture property in comparison with [011] and [111] orientations at lower and intermediate temperature.With increasing temperature to 1 040 °C,stress-rupture properties of single crystals with three principal orientations tend to be equivalent.Based on the fracture surface and microstructural observations,superior stress?rupture behavior of single crystal with [001] orientation was rationalized and the effect of misorientation of single crystal on stress rupture property was also discussed. 展开更多
关键词 single crystal superalloy stress-rupture property ANISOTROPY deformation mechanism
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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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