Hot carrier degradation and a new lifetime prediction model in ultra-deep sub-micron pMOSFET

The hot carrier effect （HCE） of an ultra-deep sub-micron p-channel metal–oxide semiconductor field-effect transistor （pMOSFET） is investigated in this paper. Experiments indicate that the generation of positively charged interface states is the predominant mechanism in the case of the ultra-deep sub-micron pMOSFET. The relation of the pMOSFET hot carrier degradation to stress time （t）, channel width （W ）, channel length （L）, and stress voltage （Vd ） is then discussed. Based on the relation, a lifetime prediction model is proposed, which can predict the lifetime of the ultra-deep sub-micron pMOSFET accurately and reflect the influence of the factors on hot carrier degradation directly.

Analysis and Modeling of Calendar Aging and Cycle Aging of LiCoO_(2)/Graphite Cells

Lithium-ion batteries are used in a wide range of applications.However,their cycle life suffers from the problem of capacity fade,which includes calendar and cycle aging.The effects of storage time,temperature and partial charge-discharge cycling on the capacity fade of Li-ion batteries are investigated in this study.The calendar aging and cycle aging are presented based on the storage and cycling experiment on LiCoO_(2)/graphite cells under different storage temperature and different ranges of state of charge(SOC).Based on the measurement data,a one-component and a double-component aging model are presented to respectively describe the capacity fade caused by calendar and cycle aging.The calendar aging of LiCoO_(2)/graphite batteries is mainly affected by temperature and SOC during the storage.Mean SOC and change in SOC(ΔSOC)are the main factors affecting battery degradation during cycling operation.

Application of Stochastic Optimization to Optimal Preventive Maintenance Problem

The contribution deals with the optimization of a sequential preventive maintenance schedule of a technical device. We are given an initial time-to-failure probability distribution, model of changes of this distribution after maintenance actions, as well as the costs of maintenance, of a device acquisition, and of the impact of failure. The maintenance timing and, eventually, its extent, are the matter of optimization. The objective of the contribution is two-fold: first, to formulate a proper (random) objective function evaluating the lifetime of the maintained device relatively to maintenance costs;second, to propose a numerical method searching for a maintenance policy optimizing selected characteristics of this objective function. The method is based on the MCMC random search combined with simulated annealing. It is also shown that such a method is rather universal for different problem specifications. The approach will be illustrated on an artificial example dealing with accelerated lifetime after each maintenance action.

Theoretical Studies on the Excited-state Properties of Ru(Ⅱ)Polypyridyl Complexes

Using DFT/TDDFT methods,the excited-state lifetimes of Ru（Ⅱ） polypyridyl complexes were computed accurately and the reason of Ru（Ⅱ） polypyridyl complexes with long excited-state lifetimes was explained by the electron-transfer distances and HOMO-LUMO gaps.Finally,the photovoltaic conversion efficiencies of complexes were predicted using DFT and docking methods.This work has provided methods of predicting the excited-state lifetimes and photovoltaic conversion efficiencies of Ru（Ⅱ） polypyridyl complexes.

锂离子电池加速老化:连接电池老化机制分析与寿命预测的桥梁

储能行业和新能源汽车的爆发式增长要求对锂离子电池的老化行为尤其是电池的寿命行为有更加深入的了解.准确地预测电池在各种工作条件下的使用寿命有助于优化电池的实际运行条件和延长电池的使用寿命,最终达到降低电池生命周期内总成本的目的.加速老化是一种经济高效的产品寿命评价方法,可以在短时间内获得大量的电池老化信息,快速预测锂离子电池在各种工作应力下的寿命特征.然而,基于加速老化进行电池寿命预测的前提是电池老化机理的一致性.本文综述了锂离子电池内各部件的老化机理和应力加速条件下的电池衰退机制以及相应的老化模式,为评价电池老化机理的一致性提供了参考.此外,本文还介绍了一些基于加速老化的电池寿命经验预测模型并为今后锂离子电池的加速老化研究提供了一些建议.