检索结果-南通市图书馆

Nanoparticle nucleation and coagulation in a mixing layer

在线全文

学校读者我要写书评

暂无评论

Acta Mechanica Sinica 2010年第4期26卷 521-529页

作者： jian-Zhong Lin Yan-hua Liu China Jiliang University 310018 Hangzhou China Department of Mechanics Zhejiang University310027 Hangzhou China

Numerical simulation of nanoparticle nucleation and coagulation in a mixing layer with sulfuric acid vapor binary system is performed using the large eddy simulation and the direct quadrature method of moment. The distributions of number concentration, volume concentration, and average diameter of nanoparticles are obtained. The results show that the coherent structures have an important effect on the distributions of number concentration, volume concentration and average diameter of nanoparticles via continuously transporting and diffusing the nanoparticles to the area of low particle concentration. In the streamwise direction, the number concentration of nanoparticles decreases, while the volume concentration and the average diameter increase. The distributions of number concentration, volume concentration and average diameter of nanoparticles are spatially inhomogeneous. The characteristic time of nucleation is shorter than that of coagulation. The nucleation takes place more easily in the area of low temperature because where the number concentration of nanoparticles is high, while the intensity of coagulation is mainly affected by the number concentration. Both nucleation and coagulation result in the variation of average diameter of nanoparticles.

关键词： Nanoparticles Nucleation - Coagulation Mixing layer Direct quadrature method of moment

Hand-eye calibration with a new linear decomposition algorithm

在线全文

学校读者我要写书评

暂无评论

Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2008年第10期9卷 1363-1368页

作者： Rong-hua LIANG jian-fei MAO College of Information Engineering Zhejiang University of Technology Hangzhou 310032 China

To solve the homogeneous transformation equation of the form AX=XB in hand-eye calibration, where X represents an unknown transformation from the camera to the robot hand, and A and B denote the known movement transformations associated with the robot hand and the camera, respectively, this paper introduces a new linear decomposition algorithm which consists of singular value decomposition followed by the estimation of the optimal rotation matrix and the least squares equation to solve the rotation matrix of X. Without the requirements of traditional methods that A and B be rigid transformations with the same rotation angle, it enables the extension to non-rigid transformations for A and B. The details of our method are given, together with a short discussion of experimental results, showing that more precision and robustness can be achieved.

关键词： Homogeneous transformation equation Singular value decomposition (SVD) Optimal rotation matrix Rigid transformations

S空位及非金属掺杂单层Bi_(2)S_(2)Se的第一性原理研究

在线全文

学校读者我要写书评

暂无评论

原子与分子物理学报 2025年第1期42卷 127-134页

作者：张建华王敏陈畅曹倩徐银湖北大学资源环境学院武汉430062

Bi_(2)S_(2)Se是一种新兴的具有优异光电性能的材料,因此受到了广泛的关注.本研究采用第一性原理方法和开源程序,研究了本征单层Bi_(2)S_(2)Se以及掺杂非金属元素X(X=P,Cl,Br和I)和S空位的体系的电子结构和光学特性.计算结果表明,改性... 详细信息

Bi_(2)S_(2)Se是一种新兴的具有优异光电性能的材料,因此受到了广泛的关注.本研究采用第一性原理方法和开源程序,研究了本征单层Bi_(2)S_(2)Se以及掺杂非金属元素X(X=P,Cl,Br和I)和S空位的体系的电子结构和光学特性.计算结果表明,改性后出现了晶格缺陷.含S空位和P、Cl、Br掺杂体系的带隙减少,而I掺杂体系的带隙增加.同时,含S空位和Cl、Br、I掺杂体系的费米能级穿过导带底,而P掺杂体系的费米能级穿过价带顶.所有改性体系在费米能级附近都出现了缺陷能级或杂质能级,表现出较高的可见光吸收能力和散射能力,改性体系的对可见光的吸收能力和散射能力有所增加.

关键词： Bi_(2)S_(2)Se 掺杂电子结构光学性质第一性原理

Determination of liquidus temperatures in high-alloyed Fe-C-Mn-Si- Al steels using differential thermal analysis

同方期刊数据库博看期刊评论

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2018年第5期25卷 546-553页

作者： Chang-ling Zhuang jian-hua Liu College of Materials and Metallurgy Guizhou UniversityGuiyang 550025 Guizhou China Engineering Research Institute University of Science andTechnology Beijing Beijing 100083 China

The liquidus temperature of the Fe-C-Mn-Si-Al alloy was investigated by using an improved differential thermal analysis method, which effectively tackles down the manganese evaporation in the course of differential thermal analysis experiments for high-manganese twinning-induced plasticity （TWIP） steels at high temperature. It was found that the liquidus temperature is more strongly dependent on the silicon content than expected. By considering the high manganese content in the Fe-C-Mn-Si-Al TWIP steels, the effect of carbon content on the depression coefficient of manganese should not be ignored, which has considerable impact on the liquidus temperature. An equation was summarized to effectively predict the liquidus temperature for a wide range of high-manganese steels. Meanwhile, the prediction results of the equation are consistent with the experimental results, as well as those results acquired from ThermoCalc.

关键词： TWIP steel Thermal analysis Liquidus temperature High-manganese steel

RATE OF CONVERGENCE OF SCHWARZ ALTERNATING METHOD FOR TIME-DEPENDENT CONVECTION-DIFFUSION PROBLEM

维普期刊数据库评论

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 Computational Mathematics 2002年第5期20卷 479-490页

作者： jian-wei Hu Cai-hua Wang School of Mathematical Sciences Nankai University300071 Tianjin China Laboratory of Computational Physics IAPCM100088 Beijing China Department of Mathematics Tianjin Normal University300073 Tianjin China

Presents a study that examined the application of an overlapping domain decomposition method to the solution of time-dependent convection-diffusion problems. Background on the Schwartz alternating procedure; Applicati... 详细信息

关键词： rate of convergence Schwarz alternating method convection-diffusion problem

Sensitivity of Sample for Simulation-Based Reliability Analysis Methods

在线全文

学校读者我要写书评

暂无评论

Computer Modeling in Engineering & Sciences 2021年第1期126卷 331-357页

作者： Xiukai Yuan jian gu Shaolong Liu School of Aerospace and Engineering Xiamen UniversityXiamen361005China Institute for Risk and Reliability Leibniz Universitat HannoverHannoverGermany

In structural reliability analysis,simulation methods are widely *** statistical characteristics of failure probability estimate of these methods have been well *** this study,the sensitivities of the failure probability estimate and its statistical characteristics with regard to sample,called‘contribution indexes’,are proposed to measure the contribution of *** contribution indexes in four widely simulation methods,i.e.,Monte Carlo simulation(MCS),importance sampling(IS),line sampling(LS)and subset simulation(SS)are derived and *** proposed contribution indexes of sample can provide valuable information understanding the methods deeply,and enlighten potential improvement of *** is found that the main differences between these investigated methods lie in the contribution indexes of the safety samples,which are the main factors to the efficiency of the ***,numerical examples are used to validate these findings.

关键词： Reliability analysis Monte Carlo simulation importance sampling line sampling subset simulation

Residual-Based False Data Injection Attacks Against Multi-Sensor Estimation Systems

维普期刊数据库评论

在线全文

维普期刊数据库

学校读者我要写书评

暂无评论

IEEE/CAA Journal of Automatica Sinica 2023年第5期10卷 1181-1191页

作者： Haibin guo jian Sun Zhong-hua Pang the National Key Laboratory of Autonomous Intelligent Unmanned Systems School of AutomationBeijing Institute of TechnologyBeijing 100081China the Beijing Institute of Technology Chongqing Innovation Center Chongqing 401120China the Key Laboratory of Fieldbus Technology and Automation of Beijing North China University of TechnologyBeijing 100144China

This paper investigates the security issue of multisensor remote estimation *** optimal stealthy false data injection(FDI)attack scheme based on historical and current residuals,which only tampers with the measurement residuals of partial sensors due to limited attack resources,is proposed to maximally degrade system estimation *** attack stealthiness condition is given,and then the estimation error covariance in compromised state is derived to quantify the system performance under *** optimal attack strategy is obtained by solving several convex optimization problems which maximize the trace of the compromised estimation error covariance subject to the stealthiness ***,due to the constraint of attack resources,the selection principle of the attacked sensor is provided to determine which sensor is attacked so as to hold the most impact on system ***,simulation results are presented to verify the theoretical analysis.

关键词： Cyber-physical systems(CPSs) false data injection(FDI)attacks remote state estimation stealthy attacks

RF design and study of a 325 MHz 7 Me V APF IH-DTL for an injector of a proton medical accelerator

在线全文

学校读者我要写书评

暂无评论

Nuclear Science and Techniques 2019年第9期30卷 34-46页

作者： Xuan Li Yue-Hu Pu Fan Yang Xiu-Cui Xie Qiang gu jian Qiao Ming-hua Zhao Shanghai Advanced Research Institute Chinese Academy of Sciences Shanghai 201210 China Shanghai Institute of Applied Physics Chinese Academy of Sciences Shanghai 201800 China University of Chinese Academy of Sciences Beijing 100049 China Shanghai APACTRON Particle Equipment Co. Ltd Shanghai 201800 China

A compact interdigital H-mode drift-tube linac (IH-DTL) with the alternating-phase-focusing (APF) method, working at 325 MHz was designed for an injector of a proton medical accelerator. When fed in with a proper RF (radio frequency) power, the DTL cavity could establish the corresponding electromagnetic field to accelerate the ‘‘proton bunches’’ from an input energy of 3 MeV to an output energy of 7 MeV successfully, without any additional radial focusing elements. The gap-voltage distribution which was obtained from the CST■ Microwave Studio software simulations of the axial electric field was compared with that from the beam dynamics, and the errors met the requirements within ± 5%. In this paper, the RF design procedure and key results of the APF IH-DTL, which include the main RF characteristics of the cavity, frequency sensitivities of the tuners, and coupling factor of the RF power input coupler are presented.

关键词： Proton therapy Proton medical accelerator Injector Drift-tube linac (DTL) Interdigital H-mode (IH) Alternating-phase-focusing (APF)

Seaweed glue as a novel polymer depressant for the selective separation of chalcopyrite and galena

在线全文

学校读者我要写书评

暂无评论

International Journal of Minerals,Metallurgy and Materials 2019年第12期26卷 1495-1503页

作者： Xiong Chen guo-hua gu Zhi-xiang Chen School of Minerals Processing and Bioengineering Central South University

The use of seaweed glue(SEG)as a novel polymer depressant for the separation of chalcopyrite from galena with butyl xanthate(BX)as a collector was studied through microflotation *** angle,adsorption,dynamic potential,and infrared spectral analyses were conducted to clarify the mechanism underlying the action of SEG on *** results of microflotation experiments indicated that chalcopyrite could be selectively separated from galena by using a SEG depressant concentration of 15 mg·L^-1,BX concentration of 10 mg·L^-1,and methyl isobutyl carbinol concentration of 8.5 mg·L^-1 at pH 8.0.A Cu concentrate with a grading of 23.68wt% was obtained at a recovery rate of 81.52% from mixed minerals with 8.29wt% Cu *** angle analysis showed that the effect of SEG on the wettability of galena was stronger than that on the wettability of ***,zeta potential,and FT-IR spectral analyses revealed that SEG and BX were coadsorbed on the surfaces of *** depressed galena by covering xanthate ions in the functional groups of-COO and mainly underwent weak physisorption on *** mechanisms account for the ability of SEG to depress galena effectively while enabling chalcopyrite flotation.

关键词： seaweed glue chalcopyrite galena flotation separation