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基于改进C4.5算法的退役动力电池等级筛选研究

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电源技术 2022年第11期46卷 1318-1321页

作者：宋汶秦王海亮赵春娟王兴贵国网甘肃省电力公司经济技术研究院甘肃兰州730000 兰州理工大学电气工程与信息工程学院甘肃兰州730050

为充分发挥退役动力电池的剩余容量、降低对环境的影响,可将其应用于电网储能电站、新能源发电、光伏路灯等不同场合。但退役的动力电池在外观、容量、内阻等性能方面还存在着不一致性,在梯次利用前须对其进行等级筛选。首先,简单介绍了... 详细信息

为充分发挥退役动力电池的剩余容量、降低对环境的影响,可将其应用于电网储能电站、新能源发电、光伏路灯等不同场合。但退役的动力电池在外观、容量、内阻等性能方面还存在着不一致性,在梯次利用前须对其进行等级筛选。首先,简单介绍了C4.5决策树算法的基本原理;然后,针对传统C4.5算法存在运行效率较低的缺陷,以构建退役动力电池等级筛选决策树为对象,对其运算过程进行了简化,同时采用K折验证法对退役动力电池筛选决策树进行优化;最后,通过退役动力锂电池数据集验证改进算法的精确性和有效性。仿真结果表明,改进的等级筛选决策树不仅可以提高算法的执行效率,而且不影响等级分类结果的精确性。

关键词：退役动力电池等级筛选决策树执行效率精确性

Quantification of grain boundary effects on the geometrically necessary dislocation density evolution and strain hardening of polycrystalline Mg-4Al using in situ tensile testing in scanning electron microscope and HR-EBSD

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Journal of Magnesium and Alloys 2024年第5期12卷 1815-1829页

作者： Eunji song Mohsen Taheri Andani Amit Misra Department of Materials Science and Engineering University of MichiganAnn ArborMI 48109USA Department of Mechanical Engineering University of MichiganAnn ArborMI 48109USA Department of Mechanical Engineering Texas A&M UniversityCollege StationTX 77843USA

In situ tensile testing in a scanning electron microscope(SEM)in conjunction with high-resolution electron backscatter diffraction(HR-EBSD)under load was used to characterize the evolution of geometrically necessary dislocation(GND)densities at individual grain boundaries as a function of applied strain in a polycrystalline Mg-4Al *** increase in GND density was investigated at plastic strains of 0%,0.6%,2.2%,3.3% from the area including 76 grains and correlated with(i)geometric compatibility between slip systems across grain boundaries,and(ii)plastic *** develop expressions for the grain boundary GND density evolution as a function of plastic strain and plastic incompatibility,from which uniaxial tensile stress-strain response of polycrystalline Mg-4Al are computed and compared with experimental *** findings in this study contribute to understanding the mechanisms governing the strain hardening response of single-phase polycrystalline alloys and more reliable prediction of mechanical behaviors in diverse microstructures.

关键词： Mg-Al alloys Grain boundaries Geometrically necessary dislocations Strain gradient plasticity HR-EBSD

Mechanomedicine:From Mechanogenomics to Mechano-Immunoengineering

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医用生物力学 2024年第S1期 5-6页

作者： song Li Department of Bioengineering and Medicine University of California

Mechanobiology is a rapidly growing field that has expanded significantly over the past 40 years. There have been great examples of mechanobiology research on the cardiovascular, musculoskeletal, and respiratory systems. The field has evolved from the system level to the organ and tissue levels, and down to the cellular and molecular levels, benefiting from scientific progress and technological developments in molecular and cell biology, biomaterials, imaging techniques, and computational tools. Additionally, the interdisciplinary integration of mechanobiology with cell engineering, tissue engineering, and drug delivery has led to promising mechanomedicine applications in both therapeutics and ***, I will discuss two examples at the molecular and cellular levels:(1) mechanical regulation of epigenomics for cell reprogramming, and (2) engineering the mechanical properties of artificial antigen-presenting cells (APCs) for immune cell modulation and cancer *** memory of its identity is determined by the epigenetic state of the cells. However, how cells control the epigenetic state and thus cell fate is not well understood, and how mechanical factors such as surface topography, cell morphology,mechanical properties of the extracellular matrix (ECM), and the mechanical deformation of cells regulate the epigenetic state is not clear. In an early study, we showed that biophysical cues, in the form of parallel microgrooves on the surface of cell-adhesive substrates, can replace the effects of small-molecule epigenetic modifiers and significantly improve reprogramming efficiency from fibroblasts to induced pluripotent stem cells. The mechanism relies on the mechanomodulation of the cells’ epigenetic state through the activity of histone deacetylase and H3 methyltransferase. We also showed that microtopography promotes a mesenchymal-to-epithelial transition in adult fibroblasts. Nanofibrous scaffolds with aligned fiber orientation produce effects similar

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Transfer of Highest Weight Modules and Small Unipotent Representations

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Acta Mathematica Sinica,English Series 2024年第3期40卷 772-791页

作者： Hai An HE Jing song HUANG Kayue Daniel WONG Department of Mathematics College of SciencesShanghai UniversityShanghai 200444P.R.China Newtouch Center for Mathematics of Shanghai University Shanghai 200444P.R.China Mathematics Research Center School of Science and EngineeringThe Chinese University of Hong KongShenzhen 518172P.R.China

We study the transfer between small special unipotent representations for all equal rank real forms of type E_(6) and E_(7). As a consequence, one can verify these modules are unitarity using the results of Wallach an... 详细信息

关键词： Unipotent representations Wallach representations Transfer of unitary modules

Receptivity of Mack modes to localized unsteady blowing and suction in a chemical non-equilibrium hypersonic boundary layer

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Acta Mechanica Sinica 2024年第7期40卷 1-18页

作者： Qingjiang Yuan Runjie song Ming Dong State Key laboratory of Nonlinear Mechanics Institute of MechanicsChinese Academy of SciencesBeijing 100190China

This paper studies the local receptivity of the Mack-mode instability to localized unsteady blowing and suction(UBS)in a chem-ical non-equilibrium(CNE)hypersonic boundary *** five-species CNE model is employed,and the receptivity efficiency is formulated by use of the residual *** with the results for the calorically perfect gas(CPG)model,we find that the real-gas effect enhances the receptivity efficiency remarkably in the majority of the second-mode frequency band,and the enhancement is mainly attributed to the modification of the base flow due to the CNE effect,which is akin to the cold-wall effect in hypersonic boundary *** with the destabilizing role of the CNE effect on the Mack second mode,it is concluded that the CNE effect would lead to a greater linearly accumulated perturbation amplitude,implying premature of transition to turbulence in a high-enthalpy hypersonic boundary layer subject to localized perturbations.

关键词： Chemical non-equilibrium flow Boundary-layer instability Hypersonic Receptivity Transition to turbulence

Online Learning-Based Offloading Decision and Resource Allocation in Mobile Edge Computing-Enabled Satellite-Terrestrial Networks

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China Communications 2024年第3期21卷 230-246页

作者： Tong Minglei Li song Han Wanjiang Wang Xiaoxiang School of Information and Communication Engineering Beijing University of Posts and TelecommunicationsBeijing 100876China Key Laboratory of Universal Wireless Communications Ministry of EducationBeijing University of Posts and TelecommunicationsBeijing 100876China School of Information and Control Engineering China University of Mining and TechnologyXuzhou 221116China School of Computer Science(National Pilot Software Engineering School) Beijing University of Posts and TelecommunicationsBeijing 100876China

Mobile edge computing(MEC)-enabled satellite-terrestrial networks(STNs)can provide Internet of Things(IoT)devices with global computing ***,the network state information is uncertain or *** deal with this situation,we investigate online learning-based offloading decision and resource allocation in MEC-enabled STNs in this *** problem of minimizing the average sum task completion delay of all IoT devices over all time periods is *** decompose this optimization problem into a task offloading decision problem and a computing resource allocation problem.A joint optimization scheme of offloading decision and resource allocation is then proposed,which consists of a task offloading decision algorithm based on the devices cooperation aided upper confidence bound(UCB)algorithm and a computing resource allocation algorithm based on the Lagrange multiplier *** results validate that the proposed scheme performs better than other baseline schemes.

关键词： computing resource allocation mobile edge computing satellite-terrestrial networks task offloading decision

Integrability and solutions of a nonsymmetric discrete Korteweg-de Vries equation

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Communications in Theoretical Physics 2024年第2期76卷 45-50页

作者： Maebel Mesfun Da-jun Zhang song-lin Zhao Department of Mathematics Shanghai UniversityShanghai 200444China Newtouch Center for Mathematics of Shanghai University Shanghai 200444China Department of Applied Mathematics Zhejiang University of TechnologyHangzhou 310023China

In this paper,we present Lax pairs and solutions for a nonsymmetric lattice equation,which is a torqued version of the lattice potential Korteweg-de Vries *** nonsymmetric equation is special in the sense that it contains only one spacing parameter but consists of two consistent cubes with other integrable lattice *** such a multidimensionally consistent property we are able to derive its two Lax pairs and also construct solutions using B?cklund transformations.

关键词： discrete Korteweg-de Vries equation nonsymmetric multi-dimensional consistency Backlund transformation solution

Influence of Sub-Cloud Secondary Evaporation Effects on the Stable Isotopes in Precipitation of Urumqi Glacier No.1,Eastern Tianshan

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Journal of Earth Science 2024年第1期35卷 177-189页

作者： Mengyuan song Zhongqin Li Feiteng Wang Xin Zhang State Key Laboratory of Cryospheric Sciences Northwest Institute of Eco-Environment and ResourcesTianshan Glaciological StationChinese Academy of SciencesLanzhou 730000China College of Geography and Environmental Science Northwest Normal UniversityLanzhou 730000China College of Sciences Shihezi UniversityShihezi 832000China

In arid regions,the stable hydrogen and oxygen isotopic composition in raindrops is often modified by sub-cloud secondary evaporation when they descend from cloud base to ground through the unsaturated *** a result of kinetic fractionation,the slope and intercept of the δ^(2)H-δ^(18)O correlation equation *** variation of deuterium excess from cloud base to the ground is often used to quantitatively evaluate the influence of secondary evaporation effect on isotopes in *** on the event-based precipitation samples collected at Urumqi Glacier No.1,eastern Tianshan during four-year observation,the existence and impact of secondary evaporation effects were analyzed by the methods of isotope-evaporation *** high air temperature,small raindrop diameter and precipitation amount,and low relative humidity conditions,the remaining rate of raindrops is small and the change of deuterium excess is large relatively,and the slope and intercept of δ^(2)H-δ^(18)O correlation equation are much lower than those of Global Meteoric Water Line,which mean that the influence secondary evaporation on precipitation *** on the conditions of low air temperature,high relative humidity,heavy rainfall,and large raindrop diameter,the change of deuterium excess is small relatively and the remaining rate of raindrops is large,and the slope and intercept of δ^(2)H-δ^(18)O correlation equation increase,the secondary evaporation is *** isotope-evaporation model described a good linear correlation between changes of deuterium excess and evaporation proportion with the slope of 0.90‰/%,which indicated that an increase of 1%in evaporation may result in a decrease of deuterium excess about 0.90‰.

关键词： stable isotopes meteoric water line deuterium excess sub-cloud secondary evaporation effect precipitation glaciers

Centennial Analysis of Human Activity Intensity and Associated Historical Events in Heilongjiang River Sino-Russo Watershed

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Chinese Geographical Science 2024年第2期34卷 280-293页

作者： song Chaoxue LI Xiaoling HE Hongshi Michael SUNDE School of Geographical Sciences Northeast Normal UniversityChangchun 130024China School of Natural Resources University of MissouriColumbia 65211USA

Human activities in a transborder watershed are complex under the influence of domestic policies,international relations,and global *** the forces driving human activity change is important for the development of transborder *** this study,we used global historical land cover data,the hemeroby index model,and synthesized major historical events to analyze how human activity intensity changed in the Heilongjiang River(Amur River in Russia)watershed(HLRW).The results showed that there was a strong spatial heterogeneity in the variation of human activity intensity in the HLRW over the past century(1900-2016).On the Chinese side,the human activity intensity change shifted from the plain areas for agricultural reclamation to the mountainous areas for timber *** the Russian side,human activity intensity changes mostly concentrated along the Trans-Siberian Railway and the Baikal-Amur *** variation of human activity intensity tended to respond to regional events while regionalized variation tends to reflect national policy change or broad international *** similarities and differences between China and Russia in policies and positions in international events resulted in synchronous and asynchronous changes in human activity ***,policy shifts were often confined by the natural features of the *** results reveal the historical origins and fundamental connotations of watershed development and contribute to formulating regional management policies that coordinate population,eco-nomic,social,and environmental activities.

关键词： human activity intensity changes hemeroby index centennial scale Heilongjiang River(Amur River in Russia)watershed China Russia