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A New Approach of Feature Selection for Text Categorization

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Wuhan University Journal of Natural Sciences 2006年第5期11卷 1335-1339页

作者： CUI Zifeng XU Baowen zhang weifeng XU Junling School of Computer Science and Engineering Southeast University Nanjing 210096 Jiangsu China Department of Computer Science and Engineering Nanjing University of Posts and TelecommunicationsNanjing 210003 Jiangsu China

This paper proposes a new approach of feature selection based on the independent measure between features for text categorization. A fundamental hypothesis that occurrence of the terms in documents is independent of each other, widely used in the probabilistic models for text categorization （TC）, is discussed. However, the basic hypothesis is incom plete for independence of feature set. From the view of feature selection, a new independent measure between features is designed, by which a feature selection algorithm is given to ob rain a feature subset. The selected subset is high in relevance with category and strong in independence between features, satisfies the basic hypothesis at maximum degree. Compared with other traditional feature selection method in TC （which is only taken into the relevance account）, the performance of feature subset selected by our method is prior to others with experiments on the benchmark dataset of 20 Newsgroups.

关键词： feature selection independency CHI square test text categorization

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气肋式充气膜结构合理拱轴线研究

防护工程 2024年第3期46卷 39-44页

作者：王乾旭赵金龙任王军陈务军张伟锋上海交通大学空间结构研究中心军事科学院国防工程研究院军事科学院国防工程研究院目标易损性评估全国重点实验室

随着空间结构的兴起和发展，出现了越来越多的气肋式膜结构建筑。为更进一步设计和优化气肋式充气膜结构，研究了其拱轴线形式，利用Abaqus有限元软件进行数值模拟，分析不同内压、不同高度气肋及不同荷载工况作用时，不同形式拱轴线的... 详细信息

随着空间结构的兴起和发展，出现了越来越多的气肋式膜结构建筑。为更进一步设计和优化气肋式充气膜结构，研究了其拱轴线形式，利用Abaqus有限元软件进行数值模拟，分析不同内压、不同高度气肋及不同荷载工况作用时，不同形式拱轴线的气肋式膜结构的变形情况，结果表明：在相同竖向气肋高度下，雪荷载作用下抛物线拱为最佳形式；风荷载作用下悬链线拱气肋为最佳形式；随着竖向气肋高度的增加，3种形式气肋的结构位移均逐渐增大，半圆形拱气肋受其影响变形变化幅度最大，故工程上应尽量选择抛物线拱气肋与悬链线拱气肋。

关键词：气肋式膜结构有限元分析合理拱轴线

Realizing a“solid to solid”process via in situ cathode electrolyte interface(CEI)by solvent-in-salt electrolyte for Li-S batteries

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Nano Research 2023年第4期16卷 5018-5025页

作者： Jiajun Huang Mengli Tao weifeng zhang Guangli Zheng Li Du Zhiming Cui Xiujun Wang Zhenxing Liang Shijun Liao Huiyu Song Guangdong Provincial Key Laboratory of Fuel Cell Technology Guangzhou 510641China School of Chemistry and Chemical Engineering South China University of TechnologyGuangzhou 510641China

Lithium-sulfur batteries(LSBs)are regarded as the most promising next-generation energy system due to their high theoretical energy ***,LSBs suffer the“shuttle effect”if undergoing the solid-liquid-solid sulfur conversion process during ***,we design a solvent-in-salt(SIS)electrolyte with co-solvent vinylene carbonate(VC)to synthesize an in situ dense cathode electrolyte interface(CEI)and successfully change sulfur conversion into a solid-solid way to avoid shuttle effect by separating the contact of sulfur and ether *** CEI is formed at the beginning of first discharge by the combined action of SIS electrolyte and filmogen *** and simulations show that SIS electrolyte controls the initial formed lithium polysulfides(LiPSs)to stay very closely on the cathode surface,and then converts them into a dense CEI *** a result,Coulombic efficiency(above 99%)and cycling performance of LSBs are ***,the in situ dense CEI can nearly stop the self-discharge of LSBs,and enable the LSBs to work under a pretty lean electrolyte condition.

关键词： lithium-sulfur battery solid-solid conversion cathode electrolyte interface no-shuttle-effect

Synthesis, supramolecular structures and luminescent properties of quinacridone derivatives bearing carbazole groups

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Chinese Science Bulletin 2009年第10期54卷 1677-1684页

作者： ZHAO GuoLi FAN Yan HUO Cheng BIAN Hang SONG weifeng zhang JingYing WANG Yue State Key Laboratory of Supramolecular Structure and Materials College of Chemistry Jilin University Changchun 130012 China

The syntheses of three carbazyl-containing quinacridone derivatives, N,N’-di((N-carbazyl)-n-butyl) quinacridone (DCBQA), N,N’-di((N-carbazyl)-n-hexyl)quinacridone (DCHQA) and N,N’-di((N-carbazyl)-n-octyl)quinacridone (DCOQA), are reported, and the photoluminescent (PL) characteristics are pre- sented. The single crystal X-ray structures of DCBQA, DCHQA and DCOQA are investigated. The crystal of DCBQA is characterized by intermolecular π…π interactions between quinacridone cores and carbazole moieties resulting in the formation of DCBQA molecule layer, in which every quinacridone core is surrounded by four carbazole groups. In DCHQA crystal, molecules assemble into two kinds of oriented columns based on intermolecular π…π interactions between quinacridone cores. The DCOQA crystal displays intermolecular CH…π and hydrogen bonding interactions feature. In DCOQA solid, every quinacridone core is sandwiched by two alkyl chains from two adjacent DCOQA molecules and simultaneously linked together with two other quinacridone cores by hydrogen bonding interactions. The PL spectra of the three compounds in solution exhibit concentration-dependent properties and their PL quantum causes decrease with the increasing concentration.

关键词：吖啶酮衍生物超分子结构发光性能合成咔唑氢键相互作用喹吖啶酮浓度依赖性

Reheat effect on the improvement in efficiency of the turbine driven by pulse detonation

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Defence Technology（防务技术） 2024年第1期31卷 200-210页

作者： Junyu Liu Zhiwu Wang Zixu zhang Junlin Li weifeng Qin Jingjing Huang School of Power and Energy Northwestern Polytechnical UniversityXi’an 710072China Shenzhen Research Institute of Northwestern Polytechnical University Shenzhen 518057China Mechanical Engineering College Xi’an Shiyou UniversityXi’an 710065China

Due to the strong unsteadiness of pulse detonation,large flow losses are generated when the detonation wave interacts with the turbine blades,resulting in low turbine *** that the flow losses are dissipated into the gas as heat energy,some of them can be recycled during the expansion process in subsequent stages by the reheat effect,which should be helpful to improve the detonationdriven turbine *** this into account,this paper developed a numerical model of the detonation chamber coupled with a two-stage axial turbine,and a stoichiometric hydrogen-air mixture was *** improvement in turbine efficiency attributable to the reheat effect was calculated by comparing the average efficiency of the stages with the efficiency of the two-stage *** research indicated that the first stage was critical in suppressing the flow unsteadiness caused by pulse detonation,which stabilized the intake condition of the second stage and consequently allowed much of the flow losses from the first stage to be recycled,so that the efficiency of the two-stage turbine was *** a 95%confidence level,the efficiency improvement was stable at 4.5%—5.3%,demonstrating that the reheat effect is significant in improving the efficiency of the detonation-driven turbine.

关键词： Pulse detonation turbine engine Hydrogen detonation Turbine efficiency Reheat effect Multi-cycle detonation

Thymic Output: Influence Factors and Molecular Mechanism

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Cellular & Molecular Immunology 2006年第5期3卷 341-350页

作者： Rong Jin Jun zhang weifeng Chen Department of Immunology School of Basic Medical Sciences Peking University Health Science Center 38 Xue Yuan Road Beijing 100083 China

Thymus is a primary lymphoid organ, able to generate mature T cells that eventually colonize secondary lymphoid organs, and is therefore essential for peripheral T cell renewal. Recent data showed that normal thymocyte export can be altered by several influence factors including several chemokines, sphingosinel-phosphate （S1P）, transcription factors such as Foxjl, Kruppel-like transcription factor 2 （KLF2） and antigen stimulation, etc. In this review, we summarized the recent reports about study strategies, influence factors and possible molecular mechanisms in thymic output. Cellular ＆ Molecular Immunology.

关键词： RTE GPCR S 1 E homeostasis

Experimental realization of honeycomb borophene

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Science Bulletin 2018年第5期63卷 282-286页

作者： Wenbin Li Longjuan Kong Caiyun Chen Jian Gou Shaoxiang Sheng weifeng zhang Hui Li Lan Chen Peng Cheng Kehui Wu Institute of Physics Chinese Academy of Sciences Beijing 100190 China School of Physical Sciences University of Chinese Academy of Sciences Beijing 100049 China School of Physics and Electronics Henan University Kaifeng 475004 China Beijing Advanced Innovation Center for Soft Matter Science and Engineering Beijing University of Chemical Technology Beijing 100029 China Collaborative Innovation Center of Quantum Matter Beijing 100871 China

We report the successful preparation of a purely honeycomb,graphene-like borophene,by using an Al(11 1) surface as the substrate and molecular beam epitaxy(MBE) growth in ultrahigh *** tunneling microscopy(STM) images reveal perfect monolayer borophene with planar,non-buckled honeycomb lattice similar as *** calculations show that the honeycomb borophene on Al(1 1 1) is energetically ***,nearly one electron charge is transferred to each boron atom from the Al(1 1 1) substrate and stabilizes the honeycomb borophene structure,in contrast to the negligible charge transfer in case of borophene/Ag(1 1 1).The existence of honeycomb 2 D allotrope is important to the basic understanding of boron chemistry,and it also provides an ideal platform for fabricating boron-based materials with intriguing electronic properties such as Dirac states.

关键词： Borophene Honeycomb structure2 D materials

Electrolyte induced synergistic construction of cathode electrolyte interphase and capture of reactive free radicals for safer high energy density lithium-ion battery

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Journal of Energy Chemistry 2023年第12期87卷 207-214,I0006页

作者： Mengfei Ding Xuning Feng Yong Peng Jing Jing Tong Bowen Hou Yalan Xing weifeng zhang Li Wang Yu Wu Jiabin Lv Chunyan Luo Dejun Xiong Shichao zhang Minggao Ouyang School of Materials Science and Engineering Beihang UniversityBeijing 100191China State Key Laboratory of Intelligent Green Vehicle and Mobility Tsinghua UniversityBeijing 100084China School of Vehicle and Mobility Tsinghua UniversityBeijing 100084China School of Mechanical and Electronic Control Engineering Beijing Jiaotong UniversityBeijing 100044China Institute of Nuclear and New Energy Technology Tsinghua UniversityBeijing 100084China School of Materials Science and Engineering Beijing Institute of TechnologyBeijing 100081China Farasis Energy(GanZhou)Co.Ltd GanZhou 341000JiangxiChina

As the energy density of battery increases rapidly,lithium-ion batteries(LIBs)are facing serious safety issue with thermal runaway,which largely limits the large-scale applications of high-energy-density *** is generally agreed that the chemical crosstalk between the cathode and anode leads to thermal runaway of ***,a multifunctional high safety electrolyte is designed with synergistic construction of cathode electrolyte interphase and capture of reactive free radicals to limit the intrinsic pathway of thermal *** cathode electrolyte interphase not only resists the gas attack from the anode but suppresses the parasitic side reactions induced by *** the function of free radical capture has the ability of reducing heat release from thermal runaway of *** dual strategy improves the intrinsic safety of battery prominently that the triggering temperature of thermal runaway is increased by 24.4℃and the maximum temperature is reduced by 177.7℃.Simultaneously,the thermal runaway propagation in module can be ***,the electrolyte design balances the trade-off of electrochemical and safety performance of high-energy *** capacity retention of LiNi_(0.8)Co_(0.1)Mn_(0.1)O_(2)|graphite pouch cell has been significantly increased from 53.85%to 97.05%with higher coulombic efficiency of 99.94%at operating voltage extended up to 4.5 V for 200 ***,this work suggests a feasible strategy to mitigate the safety risk of high-energy-density LIBs without sacrificing electrochemical performances.

关键词： Lithium-ion battery Electrolyte Battery safety Thermal runaway

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自动包布V带硫化装置的设计与节能研究

机械制造与自动化 2024年第5期53卷 171-174页

作者：宋丽荣张卫锋咸静徐国庆王蕾青岛科技大学机电工程学院山东青岛266061

针对现有包布V带硫化装置的不足,开发一种新型包布V带硫化装置,将硫化的不同工序均布设置在可旋转的圆盘底座上,可实现套模、硫化、冷却与脱模自动循环且同步完成。通过对比分析本硫化装置与传统硫化罐蒸汽消耗量,得出本硫化装置硫化一... 详细信息

针对现有包布V带硫化装置的不足,开发一种新型包布V带硫化装置,将硫化的不同工序均布设置在可旋转的圆盘底座上,可实现套模、硫化、冷却与脱模自动循环且同步完成。通过对比分析本硫化装置与传统硫化罐蒸汽消耗量,得出本硫化装置硫化一罐包布V带可节省75%的能量。通过红外测温仪测量硫化罐体的温度分布,自动硫化的连续性降低了硫化罐温度的下降幅度,硫化开始20 s后即可达到未开盖时的温度场,进一步验证了本装置的节能效果。

关键词：包布V带硫化装置节能温度场