检索结果-南通市图书馆

Journal of Materials Science & Technology 2011年第6期27卷 529-533页

作者： quan li xiaowei yin National Key Laboratory of Thermostructure Composite Materials Northwestern Polytechnical University Xi'an 710072 China

Porous silicon nitride ceramics（Si3N4） were fabricated by pressureless sintering using different particle size of silicon nitride ***2O3 was used as sintering *** to phase relationships in the ternary system Si3N4-SiO2-Lu2O3,porous Si3N4 ceramics with different phase composition were designed through the change of the content of SiO2 which was formed by the oxidation at 800℃ in *** Si3N4 with different phase compositions was obtained after sintering at 1800℃ in N2atmosphere.A small content of SiO2 favored the formation of secondary phase Lu4Si2O7N2,while large content of SiO2 favored the formation of secondary phase Lu2Si2O7 and *** Si3N4 ceramics with secondary phase Lu4Si2O7N2 had a flexural strength of 207 MPa,while that with secondary phase Si2N2O and Lu2Si2O7 had lower flexural strength.

关键词： Porous silicon nitride ceramics Secondary phase SiO2

quantum speedup and limitations on matroid property problems

在线全文

学校读者我要写书评

暂无评论

Frontiers of Computer Science 2024年第4期18卷 189-196页

作者： xiaowei HUANG Jingquan LUO Lvzhou li Institute of quantum Computing and Computer Theory School of Computer Science and EngineeringSun Yat-sen UniversityGuangzhou 510006China

Matroid theory has been developed to be a mature branch of mathematics and has extensive applications in combinatorial optimization,algorithm design and so *** the other hand,quantum computing has attracted much attention and has been shown to surpass classical computing on solving some computational ***,crossover studies of the two fields seem to be missing in the *** paper initiates the study of quantum algorithms for matroid property *** is shown that quadratic quantum speedup is possible for the calculation problem of finding the girth or the number of circuits(bases,flats,hyperplanes)of a matroid,and for the decision problem of deciding whether a matroid is uniform or Eulerian,by giving a uniform lower boundΩ■on the query complexity of all these *** the other hand,for the uniform matroid decision problem,an asymptotically optimal quantum algorithm is proposed which achieves the lower bound,and for the girth problem,an almost optimal quantum algorithm is given with query complexityO■.In addition,for the paving matroid decision problem,a lower boundΩ■on the query complexity is obtained,and an O■ quantum algorithm is presented.

关键词： quantum computing matroid quantum algorithm quantum query complexity

Harmonic State Space Based Impedance Modeling and Virtual Impedance Based Stability Enhancement Control for LCC-HVDC Systems

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Modern Power Systems and Clean Energy 2024年第1期12卷 287-298页

作者： Yifeng liu Xiaoping Zhou quan Chen Hanhang yin Lerong Hong Hao Tian ying Chen Siyuan li the College of Electrical and Information Engineering Hunan UniversityChangsha 410082China the Zhejiang Magtron Intelligent Technology limited Cooperation Jiaxing 314000China the State Grid Qianjiang Electric Power Company Qianjiang 433100China

line commutated converter based high-voltage direct-current(LCC-HVDC)transmissions are prone to harmonic oscillation under weak *** modeling is an effective method for assessing interaction ***,this paper proposes an improved calculation method for the DC voltage and AC currents of commutation stations to address the complex linearization of the commutation process and constructs an overall harmonic state-space(HSS)model of an *** on the HSS model,the closed-loop AC impedances on the LCC-HVDC sending and receiving ends are then derived and *** impedance characteristics of the LCC-HVDC are then analyzed to provide a physical explanation for the harmonic oscillation of the *** effects of the grid strength and control parameters on system stability are also *** improve the impedance characteristics and operating stability of the LCC-HVDC system,a virtual impedance based stability enhancement control is proposed,and a parameter design method is considered to ensure satisfactory phase margins at both the sending and receiving ***,simulation results are presented to verify the validity of the impedance model and virtual impedance based stability enhancement control.

关键词： line commutated converter based high-voltage direct-current(LCC-HVDC)transmission harmonic state space stability analysis harmonic oscillation virtual impedance

Self-propelled Leidenfrost droplets on femtosecond-laser-induced surface with periodic hydrophobicity gradient

在线全文

学校读者我要写书评

暂无评论

International Journal of Extreme Manufacturing 2024年第2期6卷 502-509页

作者： Bohong li Lan Jiang xiaowei li Zhipeng Wang Peng Yi Laser Micro/Nano Fabrication Laboratory School of Mechanical EngineeringBeijing Institute of TechnologyBeijingPeople’s Republic of China Beijing Institute of Technology Chongqing Innovation Center ChongqingPeople’s Republic of China Yangtze Delta Region Academy of Beijing Institute of Technology JiaxingPeople’s Republic of China

The controllable transfer of droplets on the surface of objects has a wide application prospect in the fields of microfluidic devices,fog collection and so *** Leidenfrost effect can be utilized to significantly reduce motion ***,the use of 3D structures limits the widespread application of self-propulsion based on Leidenfrost droplets in microelectromechanical *** manipulate Leidenfrost droplets,it is necessary to create 2D or quasi-2D *** this study,femtosecond laser is applied to fabricate a surface with periodic hydrophobicity gradient(SPHG),enabling directional self-propulsion of Leidenfrost *** field analysis within the Leidenfrost droplets reveals that the vapor layer between the droplets and the hot surface can be modulated by the SPHG,resulting in directional propulsion of the inner *** viscous force between the gas and liquid then drives the droplet to move.

关键词： self-propelled Leidenfrost droplets periodic hydrophobicity gradient femtosecond laser fabrication

Progress of gaseous arsenic removal from flue gas by adsorption:Experimental and theoretical calculations

在线全文

学校读者我要写书评

暂无评论

Journal of Environmental Sciences 2024年第2期136卷 470-485页

作者： Xuelei Yan Qingzhu li xiaowei Huang Bensheng li Shengtu li Qingwei Wang School of Metallurgy and Environment Central South UniversityChangsha 410083China National Engineering Research Centre for Control and Treatment of Heavy Metal Pollution Central South UniversityChangsha 410083China National Engineering Research Center for Rare Earth Materials General Research Institute for Non-Ferrous MetalsBeijing 100088China

Because of its high mobility and difficult capture,gaseous arsenic pollution control has become the focus of arsenic pollution *** mainly exists in the form of highly toxic As_(2)O_(3)in the flue ***,removing gaseous As_(2)O_(3)from flue gas is of great practical significance for arsenic pollution *** gaseous As_(2)O_(3)on the surface of adsorbents by physical or chemical adsorption is an effective way to reduce the content of arsenic in the flue gas and alleviate arsenic *** the past few decades,various adsorbents have been developed to capture gaseous As_(2)O_(3)in the flue gas,and their adsorption mechanisms have been studied in ***,it is necessary to review the strategies of arsenic removal from flue gas by adsorption,which can inspire further *** on summarizing the morphological distribution of gaseous As_(2)O_(3)in the flue gas,this review further summarizes the removal of gaseous As_(2)O_(3)by several adsorbents and the effect of temperature and the main components of the flue gas on arsenic *** addition,the mechanism of arsenic removal based on adsorption in the flue gas is discussed in depth through theoretical calculations,which is the particular focus of this ***,prospects based on the present research state of arsenic removal by adsorption are proposed to provide ideas for developing effective and stable adsorbents for arsenic removal from flue gas.

关键词： Gaseous arsenic Flue gas Adsorption Theoretical calculation Mechanism

Strain sensor on a chip for quantifying the magnitudes of tensile stress on cells

在线全文

学校读者我要写书评

暂无评论

Microsystems & Nanoengineering 2024年第3期10卷 305-315页

作者： Yuyin Zhang Yue Wang Hongze yin Jiahao Wang Na liu Songyi Zhong Long li quan Zhang Tao Yue School of Mechatronics Engineering and Automation Shanghai UniversityShanghaiChina School of Future Technology Shanghai UniversityShanghaiChina Key Laboratory of Advanced Manufacturing Technology of Zhejiang Province School of Mechanical EngineeringZhejiang UniversityHangzhouChina Shanghai Key Laboratory of Intelligent Manufacturing and Robotics Shanghai UniversityShanghaiChina Shanghai Institute of Intelligent Science and Technology Tongji UniversityShanghaiChina

During cardiac development,mechanotransduction from the in vivo microenvironment modulates cardiomyocyte growth in terms of the number,area,and arrangement ***,the response of cells to different degrees of mechanical stimuli is ***-on-a-chip,as a platform for investigating mechanical stress stimuli in cellular mimicry of the in vivo microenvironment,is limited by the lack of ability to accurately quantify externally induced ***,previous technology lacks the integration of external stimuli and feedback sensors in microfluidic platforms to obtain and apply precise amounts of external ***,we designed a cell stretching platform with an in-situ *** in-situ liquid metal sensors can accurately measure the mechanical stimulation caused by the deformation of the vacuum cavity exerted on *** platform was applied to human cardiomyocytes(AC16)under cyclic strain(5%,10%,15%,20 and 25%),and we found that cyclic strain promoted cell growth induced the arrangement of cells on the membrane to gradually unify,and stabilized the cells at 15%amplitude,which was even more effective after 3 days of *** platform’s precise control and measurement of mechanical forces can be used to establish more accurate in vitro microenvironmental models for disease modeling and therapeutic research.

关键词： stress deformation arrangement

3D-printed hierarchical porous and multidimensional conductive network based on conducting polymer/graphene oxide

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Materiomics 2024年第1期10卷 234-244页

作者： Cankun Gao Xiaoling Cui Caiyun Wang Mengya Wang Shumin Wu yin quan Peng Wang Dongni Zhao Shiyou li School of Petrochemical Technology Lanzhou University of TechnologyLanzhou730050China Key Laboratory of Low Carbon Energy and Chemical Engineering of Gansu Province Lanzhou730050China Gansu Engineering Laboratory of Cathode Material for lithium-ion Battery Baiyin730900China ARC Centre of Excellence for Electromaterials Science Intelligent Polymer Research InstituteUniversity of WollongongAIIM FacilityInnovation CampusNorth WollongongNSW2500Australia

Designing ultrathick and hierarchical electrodes is effective to deal with the challenge of high areal capacity and high power density for lithium-ion batteries(liBs)***,a thick electrode with hierarchical porous and multidimensional conductive network is fabricated by 3D printing tech-nology,in which both the conducting polymer of poly(3,4-ethylene dioxythiophene):polystyrene sul-fonate(PEDOT:PSS)and graphene oxide(GO)play the dual roles as binders and conductive *** a consequence,the 3D-printed thick electrode(~900 mm)with a mass loading of~47 mg/cm^(2) exhibits a good rate capability of 122 mA·h/g at 2 C,a high areal capacity of up to 5.8 mA·h/cm^(2),and stable cycling performance of~95%capacity retention after 100 ***,the C-O-S bond is further confirmed by the spectral analysis and the DFT calculation,which not only hinders the stack of nanosheets but enhances the mechanical stability and electronic conductivity of electrodes.A stable covalent multidi-mensional conductive network constructed by 3D-printing technology provides a new design strategy to improve the performance of liBs.

关键词： 3D printing PEDOT:PSS Thick electrodes Areal capacity lithium-ion batteries

Interference-induced suppression of particle emission from a Bose-Einstein condensate in lattice with time-periodic modulations

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Chinese Physics B 2024年第10期33卷 153-158页

作者： Long-quan Lai Zhao li School of Science Nanjing University of Posts and TelecommunicationsNanjing 210023China School of Electronic Engineering Chengdu Technological UniversityChengdu 611730China

Emission of matter-wave jets from a parametrically driven condensate has attracted significant experimental and theoretical attention due to the appealing visual effects and potential metrological *** this work,we investigate the collective particle emission from a Bose-Einstein condensate confined in a one-dimensional lattice with periodically modulated interparticle *** give the regimes for discrete modes,and find that the emission can be distinctly *** configuration induces a broad band,but few particles are ejected due to the interference of the matter *** further qualitatively model the emission process and demonstrate the short-time *** engineering provides a way to manipulate the propagation of particles and the corresponding dynamics of condensates in lattices,and may find application in the dynamical excitation control of other nonequilibrium problems with time-periodic driving.

关键词： Bose-Einstein condensate matter-wave jet periodic modulation

Measurement of acceleration and angular velocity of particles during a 3D silo discharge

在线全文

学校读者我要写书评

暂无评论

Particuology 2024年第9期92卷 61-71页

作者： Tongtong Mu Yiming li quan Chen Ran li Hui Yang College of Medical Instrument Shanghai University of Medicine and Health SciencesShanghai201318China School of Optical-Electrical and Computer Engineering University of Shanghai for Science and TechnologyShanghai200093China

Accurate measurement of the three-dimensional(3D)movement of discrete particles is crucial for comprehending complex granular rheology in *** this paper,the acceleration and angular velocity of particles in 3D silos are measured by using a spherical detector based on inertial technology and magnetic positioning *** acceleration of particles is the largest in the center of silos,which suggest that the resistance generated by friction and extrusion is the ***,the angular velocity distribution follows lognormal function except for particles near the *** correlation between acceleration and angular velocity is opposite in different flow *** reveals for the first time that the extent to which the resultant force on the particles affects their rotational motion is related to the flow *** results have practical significance for regulating the granular flow pattern and optimizing the structural design of silos.

关键词： Granularflow Silo Angular velocity Acceleration

High-precision X-ray characterization for basic materials in modern high-end integrated circuit

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

Journal of Semiconductors 2024年第7期45卷 12-24页

作者： Weiran Zhao Qiuqi Mo li Zheng Zhongliang li xiaowei Zhang Yuehui Yu National Key Laboratory of Materials for Integrated Circuits Shanghai Institute of Microsystem and Information TechnologyChinese Academy of SciencesShanghai 200050China School of Physical Science and Technology ShanghaiTech UniversityShanghai 201210China Shanghai Synchrotron Radiation Facility Shanghai Advanced Research InstituteChinese Academy of SciencesShanghai 201204China Beijing Synchrotron Radiation Facility Institute of High Energy PhysicsChinese Academy of ScienceBeijing 100049China

Semiconductor materials exemplify humanity's unwavering pursuit of enhanced performance,efficiency,and functionality in electronic *** its early iterations to the advanced variants of today,this field has undergone an extraordinary *** the reliability requirements of integrated circuits continue to increase,the industry is placing greater emphasis on the crystal ***,conducting a range of characterization tests on the crystals has become *** paper will examine the correlation between crystal quality,device performance,and production yield,emphasizing the significance of crystal characterization tests and the important role of high-precision synchrotron radiation X-ray topography characterization in semiconductor ***,we will cover the specific applications of synchrotron radiation characterization in the development of semiconductor materials.

关键词： X-ray topography synchrotron radiation semiconductor materials crystal defects