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Rare Metals 2021年第9期40卷 2440-2446页

作者： Shuai-Jin wu Zhao-Hui wu Sheng Fang Xiao-Peng Qi Bing Yu Juan-Yu Yang Grinm Group Co. Ltd.Beijing 100088China general Research Institute for Nonferrous Metals Beijing 100088China China Automotive Battery Research Institute Co. Ltd.Beijing 101407China

Silicon materials have attracted wide attention as negative materials due to exceptional gravimetric capacity and abundance. The strategy of using nano-silicon materials as structural units to construct nano/micro-structured silicon-based negative materials for lithium-ion batteries has come into sight in recent years. In order to provide guidance for the material structure design of micro-sized silicon-based negative materials in practical application, in this work, two commercialized nano/micro-structured silicon-based negative materials with a specific capacity of about 650 mAh·g^(-1) were investigated and compared in the aspects of material microstructure, electrochemical performance of half cells, and electrode morphological evolution during cycling. The cycling performance(with capacity retention ratio of about 17% higher after 100 cycles) and electrode structure maintenance of the embedded structure Si/C material are superior to those of core–shell Si/C material. This research can provide guidance on design and application of nano/micro-structured silicon-based negative materials.

关键词： Lithium-ion battery Negative materials Silicon-based materials Material structure

Influence of floc dynamic protection layer on alleviating ultrafiltration membrane fouling induced by humic substances

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Journal of Environmental Sciences 2020年第4期32卷 10-19页

作者： Baiwen Ma Siqi wu Bodong Wang Zenglu Qi Yaohui Bai Huijuan Liu Jiuhui Qu Ruijun wu Key Laboratory of Drinking Water Science and Technology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing100085China University of Chinese Academy of Sciences Beijing100049China School of Environmental and Municipal Engineering Xi’an University of Architecture and TechnologyXi'an710055China School of Environment State Key Joint Laboratory of Environment Simulation and Pollution ControlTsinghua UniversityBeijing100084China Research Center for Water Quality and Ecology Tsinghua UniversityBeijing100084China State Key Laboratory of Membrane Materials and Membrane Applications Tianjin Motimo Membrane Technology Co.Ltd.Tianjin300457China

Cake layer formation is inevitable over time for ultrafiltration(UF)membrane-based drinking water *** the cake layer is always considered to cause membrane fouling,it can also act as a"dynamic protection layer",as it further adsorbs pollutants and dramatically reduces their chance of getting to the membrane ***,the UF membrane fouling performance was investigated with pre-deposited loose flocs in the presence of humic acid(HA).The results showed that the floc dynamic protection layer played an important role in removing *** higher the solution pH,the more negative the floc charge,resulting in lower HA removal efficiency due to the electrostatic repulsion and large pore size of the floc *** decreasing solution pH,a positively charged floc dynamic protection layer was formed,and more HA molecules were *** potential reasons were ascribed to the smaller floc size,greater positive charge,and higher roughness of the floc ***,similar membrane fouling performance was also observed for the negative and positive floc dynamic protection layers due to their strong looseness *** addition,the molecular weight(MW)distribution of HA also played an important role in UF membrane fouling *** the small MW HA molecules,the chance of forming a loose cake layer was high with a negatively charged floc dynamic protection layer,while for the large MW HA molecules it was high with a positively charged floc dynamic protection *** a result,slight UF membrane fouling was induced.

关键词： Ultrafiltration Floc dynamic protection layer Humic substances Fouling alleviation

Understanding the efficient microwave absorption for Fe Co@ZnO flakes at elevated temperatures a combined experimental and theoretical approach

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Journal of Materials Science & Technology 2022年第30期125卷 212-221页

作者： Kangsen Peng Chuyang Liu Yuhan wu Gang Fang Guoyue Xu Yujing Zhang Chen wu Mi Yan School of Material Science and Technology Nanjing University of Aeronautics and AstronauticsNanjing 211106China School of Materials Science and Engineering Nanjing University of Science and TechnologyNanjing 210094China State Key Laboratory of Silicon Materials Zhejiang UniversityHangzhou 310027China

Considerable microwave absorption performance at elevated temperatures is highly demanded in both civil and military *** dielectric or magnetic absorbers are difficult to attain efficient and broadband microwave absorption at the high temperature range of 373 K-573 K,and the evolution mechanism of the microwave absorption is still unclear especially for the magnetic ***,ZnO coated flaky-FeCo composite is proposed to break through the bottleneck,which possesses microwave absorption(RLge of 298 K-573 K with a thickness of only~2 ***,attenuation mechanism and evolution of the microwave absorption properties for the FeCo@ZnO flaky material at elevated temperature has been clearly disclosed by the composition and microstructure characterizations,electromagnetic performance measurements and first principles calculations for the first ***,the Poynting vector,volume loss density,magnetic field(H)and electric field(E)are simulated by HFSS to understand the interaction between EM waves and the samples at different temperatures,further elaborating the attenuation mechanism in high-temperature *** study provides guidance in designing and developing high-temperature microwave absorbers for the next generation.

关键词： Zn O coated flaky-FeCo High-temperature microwave absorption First principles calculation HFSS simulation

Majorana modes in solid state systems and its dynamics

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Frontiers of physics 2018年第2期13卷 103-109页

作者： Qi Zhang Biao wu College of Science Zhejiang University of Technology Hangzhou 310014 China International Center for Quantum Materials School of Physics Peking University Beijing 100871 China Collaborative Innovation Center of Quantum Matter Beijing 100871 China Wilczek Quantum Center School of Physics and Astronomy Shanghai Jiao Tong University Shanghai 200240 China

We review the properties of Majorana fermions in particle physics and point out that Majorana modes in solid state systems are significantly different. The key reason is the concept of anti-particle in solid state systems is different from its counterpart in particle physics. We define Majorana modes as the eigenstates of Majorana operators and find that they can exist both at edges and in the bulk. According to our definition, only one single Majorana mode can exist in a system no matter at edges or in the bulk. Kitaev＇s spinless p-wave superconductor is used to illustrate our results and the dynamical behavior of the Majorana modes.

关键词： Majorana mode Majorana operator anti-particle Kitaev's model dynamical behavior

A Numerical Study of Densification Behavior of Silicon Carbide Matrix Composites in Isothermal Chemical Vapor Infiltration

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Journal of wuhan University of Technology(Materials Science) 2018年第6期33卷 1365-1371页

作者： GUAN Kang wu Jianqing CHENG Laifei School of Materials Science and Engineering South China University of Technology Science and Technology on Thermostructural Composite Materials Laboratory School of Materials Science and Engineering Northwestern Polytechnical University

We studied the characteristics of two-scale pore structure of preform in the deposition process and the mass transfer of reactant gas in dual-scale pores, and observed the physiochemical phenomenon associated with the reaction. Thereby, we established mathematical models on two scales, respectively, preform and reactor. These models were used for the numerical simulation of the process of ceramic matrix composites densified by isothermal chemical vapor infiltration(ICVI). The models were used to carry out a systematic study on the influence of process conditions and the preform structure on the densification behaviors. The most important findings of our study are that the processing time could be reduced by about 50% without compromising the quality of the material, if the processing temperature is 950-1 000 ℃ for the first 70 hours and then raised to 1 100 ℃.

关键词： isothermal chemical vapor infiltration ceramic matrix composites process parameters fiber preform structure densification behavior

2-(4-戊基苯甲酰)苯甲酸在C_6—C_8烷烃中溶解度的测定与关联

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化学工程 2014年第6期42卷 43-47页

作者：师新阁郭志武杨索和靳海波北京石油化工学院化工系北京102617 北京化工大学化学工程学院北京100029

2-(4-戊基苯甲酰)苯甲酸(ABB酸)是合成2-戊基蒽醌的重要中间体,简便高效地从反应混合物中分离纯的ABB酸是合成2-戊基蒽醌的关键步骤。文中采用液相色谱仪内标法测试了ABB酸质量浓度范围为0.9×10-9—21×10-9g/L标准液的峰面积,建立了AB... 详细信息

2-(4-戊基苯甲酰)苯甲酸(ABB酸)是合成2-戊基蒽醌的重要中间体,简便高效地从反应混合物中分离纯的ABB酸是合成2-戊基蒽醌的关键步骤。文中采用液相色谱仪内标法测试了ABB酸质量浓度范围为0.9×10-9—21×10-9g/L标准液的峰面积,建立了ABB酸质量浓度与峰面积的线性关系。利用该线性关系,采用平衡法实验测定了系列温度下,ABB酸在直链烷烃(正己烷、正庚烷、正辛烷)体积分数为0.750—0.875的直链烷烃/邻二氯苯混合液体系中的溶解度数据。ABB酸在混合溶剂中的溶解度随直链烷烃的体积分数增大而降低,随温度降低而降低。采用溶剂析出法从溶剂中分离ABB酸时,温度应低于283.15 K,直链烷烃的体积分数大于0.84,直链烷烃使用正己烷。使用修正的λ-h方程关联了实验数据,修正项具有普适性。所有结果均取3次测试结果的平均值。

关键词： 2-(4-戊基苯甲酰)苯甲酸溶解度固液平衡直链烷烃/邻二氯苯

超临界CO_2萃取老挝产鸡蛋花挥发油的研究

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中药材 2011年第5期34卷 789-794页

作者：肖新玉崔龙海周欣欣吴燕葛发欢广州中医药大学广东广州510405 中药提取分离过程现代化国家工程研究中心广东广州510240

首次采用正交试验设计对老挝产鸡蛋花挥发油的超临界CO2萃取工艺提取进行优化,并与水蒸气蒸馏法进行比较,得最佳萃取条件为:萃取压力25 MPa,萃取温度45℃;分离釜I压力12 MPa,温度55℃;分离釜Ⅱ压力6 MPa,温度30℃,在此工艺条件下的收率... 详细信息

首次采用正交试验设计对老挝产鸡蛋花挥发油的超临界CO2萃取工艺提取进行优化,并与水蒸气蒸馏法进行比较,得最佳萃取条件为:萃取压力25 MPa,萃取温度45℃;分离釜I压力12 MPa,温度55℃;分离釜Ⅱ压力6 MPa,温度30℃,在此工艺条件下的收率为5.8927%。应用气相色谱-质谱联用技术对鸡蛋花挥发油化学成分进行鉴定,用归一化法测定其相对含量。超临界萃取物主要成分有橙花叔醇、柳酸苄酯、邻苯二甲酸二异丁酯等53种化学成分,其中邻苯二甲酸二异丁酯含量高达66.11%,与水蒸气蒸馏法有较大差异。

关键词：鸡蛋花挥发油超临界CO2流体萃取法气相色谱-质谱

Interpretation and Translation of Metonymy in English and Chinese

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学术界 2014年第6期 259-265页

作者： wu Shuqiong School of Foreign Languages Southwest University of Political Science and Law Chongqing 401120

Metonymy is traditionally regarded as a figure of speech,which involves a relation of substitution. Accordingly,previous studies on metonymy translation mainly focused on the correspondence of metonymic structures between source text and target text. In cognitive linguistics,metonymy is viewed as an important cognitive mechanism of human being. Conceptual metonymy is embodied,ubiquitous and culture-specific in nature. Based on the translation theory of functional equivalence,this paper argues that the principle to judge the metonymy translation is not on the equivalence of words or expressions but the underlying metonymic thinking. The translation should try to help the target readers acquire the same cognitive experience as the readers of the original. In addition,metonymy translation should maintain the rhetorical function of metonymy in the source text. According to these principles,this paper has come up with four strategies for metonymy translation: literal translation,literal translation with explanatory note,converting the vehicle in the metonymy and free *** metonymy translation from the perspective of cognitive linguistics can throw a new light on translation.

关键词：翻译中国英语对应关系语言学文本解释性读者

Numerical simulation of humping phenomenon in high speed gas metal arc welding

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Frontiers of Materials Science 2011年第2期5卷 90-97页

作者： Ji CHEN Chuan-Song wu State Key Lab of Advanced Welding Production Technology Harbin Institute of Technology Harbin 150001 China Institute of Materials Joining Shandong University Jinan 250061 China

It is of great significance to obtain a thorough understanding of the physical mechanisms responsible for humping bead phenomenon in high speed gas metal arc welding （GMAW） in order to raise welding efficiency. Experiments were conducted to observe the weld pool behaviors in high speed GMAW, and it was found that both the severely deformed weld pool surface and strong backward flowing play a dominant role in humping bead formation. In this study, a mathematical model is developed to quantitatively analyze the forming mechanism of humping beads for high speed GMAW through considering both the momentum and heat content distribution of the backward flowing molten metal inside the weld pool. The transient development of temperature profiles in the weld pool with severe deformation demonstrates the humping bead forming process under some welding conditions. The predicted and measured humping bead dimensions are in agreement.

关键词： numerical simulation humping weld bead high-speed GMAW

On the Adjoint of Operator Matrices with Unbounded Entries II

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Acta Mathematica Sinica,English Series 2015年第6期31卷 995-1002页

作者： De Yu wu Alatancang CHEN School of Mathematical Sciences Inner Mongolia University Department of Mathematics Hohhot University for Nationalities

In this paper, the adjoint of a densely defined block operator matrix L=[A B C D] in a Hilbert space X ×X is studied and the sufficient conditions under which the equality L＊=[A＊ B＊ C＊ D＊] holds are obtained thr... 详细信息

关键词： Block operator matrix adjoint operator Frobenius-Schur factorization