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Nanoscale Morphology in Tensile Fracture of a Brittle Amorphous Ribbon

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Journal of Materials Science & Technology 2008年第5期24卷 745-749页

作者： Xifeng LI. kaifeng ZHANG Guofeng wang School of Materials Science and Engineering Harbin Institute of Technology Harbin 150001 China

The paper reports on the observation of nanoscale morphology on the tensile fracture surface of a brittle amorphous Fe-based ribbon. The formation of nanoscale damage cavity structure is a main characteristic morphology on the fracture surfaces. Approaching the ribbon boundary, these damage cavities assemble and form the nanoscale periodic corrugations, which are neither Wallner lines nor crack front waves. The periodic corrugations result from the interactions between the reflected elastic waves by the boundaries of amorphous ribbon and the stress fields of the crack tip.

关键词： Nanoscale periodic corrugation Damage cavity Tensile fracture Brittle amorphous ribbon

Finite-Element Simulation and Experimental Research of the Hot-Press Sintering of Nano-Sized Ceramic Powders

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Journal of Materials Science & Technology 2003年第Z1期19卷 40-42页

作者： Guoqing CHEN kaifeng ZHANG Guofeng wang Yandong YU Department of Materials Engineering Harbin Institute of Technology Harbin 150001 China Department of Materials Engineering Harbin Institute of Technology Harbin 150001 China Department of Materials Engineering Harbin Institute of Technology Harbin 150001 China Department of Materials Engineering Harbin Institute of Technology Harbin 150001 China

Numerical simulation of hot-press sintering of nano-sized ceramic powders was introduced by the commercial finite element code ***. The powder plastic model and the thermo-mechanical coupled quadrilateral element were developed and adopted in the simulation. The mechanical and thermal properties of the nano-sized alumina based powders were *** addition, the experimental research and numerical simulation of the sintering process of different initial densities were carried out. The stress state in sintering of green compacts with different initial densities was analyzed by the densification *** reason for the density fluctuations of as-sintered ceramic bulks was found out.

关键词： Sintering, Finite element method, Green compacts, Stress

In vitro thyroid disrupting effects of organic extracts from WWTPs in Beijing

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Journal of Environmental Sciences 2011年第4期23卷 671-675页

作者： Na Li Mei Ma kaifeng Rao Zijian wang State Key Laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China.

It is generally known that there are many endocrine disrupting compounds （EDCs） in the effluents from wastewater treatment plants （WWTPs）. Most research has focused on the occurrence of estrogenic or androgenic activities, while ignoring that there are environmental chemicals disrupting thyroid system, which is essential for growth and development in both humans and animals. In the present work, a two-hybrid yeast assay was conducted to evaluate the removal efficiencies of agonistic or antagonistic thyroid receptor （TR） mediated effects in different treatment processes of three WWTPs located in Beijing. We found no TR agonistic, but TR antagonistic activities in all processes from the WWTPs. The TR antagonistic activities in organic extracts of water samples were then calibrated regarding to a known TR-inhibitor, amiodarone hydrochloride （AH）. The observed concentration of TR disrupting substances ranged from 2.35 × 10 8 to 6.19 × 10 7 mol/L AH in Gaobeidian WWTP, 3.76 × 10 8 to 8.75 × 10 8 mol/L AH in Lugouqiao WWTP, and 4.80 × 10 9 to 2.55 × 10 8 mol/L AH in Beixiaohe WWTP. Of the three WWTPs, the removal rates were 92.7%, 42.2%, and 23.1% respectively. Industrial sewage may contain more TR disrupting substances compared with domestic sewage. The recipient waters were found to contain considerable concentrations of TR disrupting substances that may cause adverse effects on the exposed organisms.

关键词： recombinant yeast assay thyroid receptor wastewater

Physical investigation of subthreshold swing degradation behavior in negative capacitance FET

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Science China(Information Sciences) 2022年第6期65卷 241-246页

作者： Mengxuan YANG Qianqian HUANG kaifeng wang Chang SU Liang CHEN Yangyuan wang Ru HUANG Key Laboratory of Microelectronic Devices and Circuits (MOE) Institute of MicroelectronicsPeking University Beijing Laboratory of Future IC Technology and Science Peking University

Power consumption has become one of the bottlenecks limiting the future development of integrated circuits. Tunnel FETs(TFETs) and negative capacitance FETs(NCFETs) can break the subthreshold swing limitation(60 mV/dec at room temperature) of conventional metal-oxide-semiconductor field-effect transistor(MOSFET) to reduce the operating voltage and thus power consumption. However, induced by the band-to-band tunneling mechanism, TFETs have a subthreshold swing degradation issue and relatively low ON current. Although NCFETs with ferroelectric/dielectric gate stack can theoretically maintain a high ON current comparable to conventional MOSFET, the physical origin of sub-60 SS is controversial and the mechanism of switching behavior in NCFET is still not clear. In this work, by experimentally investigating the whole negative differential capacitance process and its gate voltage amplification coefficient, an intrinsic issue of SS degradation with increased gate voltage is also found in NCFET for the first time. Based on the physical investigation and simulation results, it is shown that the intrinsic SS degradation in NCFET is resulting from the instant dielectric polarization response. Both the decrease of dielectric thickness and the increase of dielectric constant may lead to the severer SS degradation, which is not favorable for scaled NCFETs.

关键词： ferroelectric negative differential capacitance effect polarization low power voltage amplification

A Fuzzy Hierarchical Strategy for Improving Frequency Regulation of Battery Energy Storage System

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Journal of Modern Power Systems and Clean Energy 2021年第4期9卷 689-698页

作者： kaifeng wang Ying Qiao Lirong Xie Jiaming Li Zongxiang Lu Huan Yang School of Electrical Engineering Xinjiang UniversityUrumqiChina State Key Laboratory of Control and Simulation of Power Systems Generation Equipments of Electrical Engineering Tsinghua UniversityBeijingChina

Battery energy storage systems(BESSs)can provide instantaneous support for frequency regulation(FR)because of their fast response ***,purely pursuing a better FR effect calls for continually rapid cycles of BESSs,which shortens their lifetime and deteriorates the operational *** coordinate the lifespan savings and the FR effect,this paper presents a control strategy for the FR of BESSs based on fuzzy logic and hierarchical *** fuzzy logic controller improves the effect of FR by adjusting the charging/discharging power of the BESS with a higher response speed and precision based on the area control error(ACE)signal and the change rate of ACE in a non-linear *** controllers effectively reduce the life loss by optimizing the depth of discharge,which ensures that the state of charge(SOC)of BESS is always in the optimal operating range,and the total FR cost is the lowest at this *** proposed method can achieve the optimal balance between ACE reduction and operational economy of *** effectiveness of the proposed strategy is verified in a two-area power system.

关键词： Battery energy storage system(BESS) frequency regulation(FR) coordinated control strategy optimal depth of discharge charging/discharging threshold

Enhanced photoelectrocatalytic decomplexation of Ni-EDTA and simultaneous recovery of metallic nickel via TiO_(2)/Ni-Sb-SnO_(2) bifunctional photoanode and activated carbon fiber cathode

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Journal of Environmental Sciences 2023年第4期126卷 198-210页

作者： Juanjuan Zhang Jing Luo Xu Zhao kaifeng wang Tengfei Xie Tongguang Xu Meng Qiao Key Laboratory of Drinking Water Science and Technology Research Center for Eco-Environmental SciencesChinese Academy of SciencesBeijing 100085China University of Chinese Academy of Sciences Beijing 100049China Beijing Drainage Group Co. Ltd.Beijing 100044China Beijing Engineering Research Center of Wastewater Resource Beijing 100124China Beijing Third Class Tobacco Supervision Station Beijing 101121China

In order to enhance Ni-EDTA decomplexation and Ni recovery via photoelectrocatalytic (PEC)process,TiO_(2)/Ni-Sb-SnO_(2)bifunctional electrode was fabricated as the photoanode and activated carbon fiber (ACF) was introduced as the *** a cell voltage of 3.5 V and initial solution pH of 6.3,the TiO_(2)/Ni-Sb-SnO_(2)bifunctional photoanode exhibited a synergetic effect on the decomplexation of Ni-EDTA with the pseudo-first-order rate constant of 0.01068 min^(-1)with 180 min by using stainless steel (SS) cathode,which was 1.5 and 2.4times higher than that of TiO_(2)photoanode and Ni-Sb-SnO_(2)anode,***,both the efficiencies of Ni-EDTA decomplexation and Ni recovery were improved to 98%from 86%and 73%from 41%after replacing SS cathode with ACF cathode,*** factors on Ni-EDTA decomplexation and Ni recovery were investigated and the efficiencies were favored at acidic condition,higher cell voltage and lower initial Ni-EDTA ***-EDTA was mainly decomposed via·OH radicals which generated via the interaction of O_(3),H_(2)O_(2),and UV irradiation in the contrasted PEC ***,the liberated Ni^(2+)ions which liberated from Ni-EDTA decomplexation were eventually reduced to metallic Ni on the ACF cathode ***,the stability of the constructed PEC system on Ni-EDTA decomplexation and Ni recovery was exhibited.

关键词： Photoelectrocatalytic TiO_(2)/Ni-Sb-SnO_(2)bifunctional photoanode Activated carbon fiber cathode Ni-EDTA decomplexation Ni recovery

Microstructure in the Semi-solid State and Mechanical Properties of AZ80 Magnesium Alloy Reheated from the As-cast and Extruded States

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Acta Metallurgica Sinica(English Letters) 2013年第4期26卷 473-482页

作者： Wenyong JIANG Tian CHEN Liping wang Yicheng FENG Yan ZHU kaifeng wang Jiapeng LUO Shouwei ZHANG College of Materials Science and Engineering Harbin University of Science and Technology

The multi-axial forging （MAF） process was introduced into the strain induced metal activation （SIMA） process to replace conventional forging. Microstructure evolution of MAF formed AZ80 magnesium alloy during partial remelting was investigated. Furthermore, the tensile mechanical properties for AZ80 magnesium alloy thixoextruded from the starting materials treated by MAF were determined. For comparison, as-cast AZ80 magnesium alloy was also thixoextruded. The results show that the SIMA route produced ideal, fine semi-solid microstructure, in which almost completely spheroidal primary solid grains had a little amount of entrapped liquid. The microstructure of the as-cast alloy in the semi-solid state is less spheroidized compared with the MAF alloy under the similar isothermal holding conditions. With prolonged holding time, the size of the solid grain increases and the degree of spheroidization is improved in the MAF formed alloys. However, the solid grain size of the as-cast alloys decreases initially, and then increases with further increasing temperature. The tensile mechanical properties for AZ80 magnesium alloy thixoextruded from the starting material produced by MAF are better than those of AZ80 magnesium alloy thixoextruded from the starting material produced by casting. The ultimate tensile strength, yield strength and elongation of the alloy thixoextruded from the starting material produced by MAF are 314 MPa, 238 MPa and 14%, respectively.

关键词： Magnesium alloy Microstructure Mechanical properties Partial remelting

Evaluation of infill well pattern based on the dynamic change of reservoirs during coalbed methane development

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Frontiers of Earth Science 2023年第3期17卷 646-660页

作者： Qian ZHANG Shuheng TANGI Songhang ZHANG Xinlu YAN kaifeng wang Tengfei JIA Zhizhen wang School of Energy Resources China University of Geosciences(Beijing)Beijing 100083China Coal Reservoir Laboratory of National Engineering Research Center of CBM Development&Utilization Beijing 100083China Beijing Key Laboratory of Unconventional Natural Gas Geological Evaluation and Development Engineering Beijing 100083China College of Mining Technology Taiyuan University of TechnologyTaiyuan 030024China

With the deepening of coalbed methane(CBM)exploration and development,the problem of low gas production has gradually become one of the main factors restricting the development of the CBM industry in *** well pattern deployment can improve the productivity of CBM wells and reduce the cost of production,while the reservoir changes of CBM wells play a important role for well pattern *** this study,the dynamic characteristics of the average reservoir pressure(ARP),permeability,and drainage radius during the development process of CBM wells are systematically analyzed,and predicted the production changes of well groups before and after infilling wells in combination with the characteristics of reservoir *** results show that the high gas production wells have a larger pressure drop,long drainage radius,and a large increase in *** the contrary,low gas production wells are characterized by small drainage radius,damaged permeability and difficult to *** productivity of infilled horizontal wells is predicted for two well groups with different productivity and reservoir dynamic *** infilling wells,the production of current wells has increased at different *** is predicted that the average gas production of low gas production well group H1 and middle gas production well group H2 will increase 1.64 and 2.09 times respectively after 3000 days production *** addition,the pressure interference between wells has increased significantly,and the overall gas production of the well group has greatly *** wells can achieve better development results in areas with superior CBM resources,recoverable reservoir permeability,and small drainage radius during the early production *** research results provide a reference for the later infill adjustment of CBM well patterns in the study area.

关键词： well pattern optimization reservoir dynamic variation infill well deployment coalbed methane Qinshui Basin

Susceptibility of male and female Japanese medaka （Oryzias latipes） to 2,4,6-trichlorophenol-induced micronuclei in peripheral erythrocytes

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Frontiers of Environmental Science & Engineering 2013年第1期7卷 77-84页

作者： Nannan LIU Mei MA Yiping XU Jinmiao ZHA kaifeng RAO Zijian wang State Key Laboratory of Environmental Aquatic Chemistry Research Center for Eco-Environmental Sciences Chinese Academy of Sciences Beijing 100085 China

2,4,6-trichlorophenol (2,4,6-TCP) is a widespread probable human carcinogen and has been proven to have genotoxicity in in vitro assays. However, little genotoxicity information and no micronuclei induction data for 2,4,6-TCP is available from in vivo tests, especially for sex-specific differences. Following a preliminary test, a piscine peripheral erythrocyte micronucleus assay was conducted on medaka (Oryzias latipes) after a 28-day exposure to 2,4,6-TCP. In the present study, the mean micronuclei (MNC) frequencies of all of the groups increased in a dose-dependent manner, which indicated the potential genotoxicity of 2,4,6-TCP. Moreover, males were found to be more susceptible compared with females after a 28-day exposure to 2,4,6-TCP in all of the dosed groups above 10 μg·L−1. This is the first report on the potential of micronuclei induction and a sex-susceptible effect in the peripheral erythrocytes of mature fish after 2,4,6-TCP in vivo exposure.

关键词： 2 4 6-trichlorophenol genotoxicity Japanese medaka piscine micronucleus test in peripheral erythrocytes gender difference