检索结果-南通市图书馆

原子与分子物理学报 2025年第4期42卷 27-32页

作者： XU Jian-Qiang MA Zhao-Peng CHENG Si liu zhi-Cong ZHU Guang-Lai Department of Physics School of Physics and Electronic InformationAnhui Normal UniversityWuhu 241002China

The microstructures and thermodynamic properties of mixed systems comprising pyridinium ionic liquid[HPy][BF_(4)]and acetonitrile at different mole fractions were studied using molecular dynamics simulation in this *** following properties were determined:density,self-diffusion coefficient,excess molar volume,and radial distribution *** results show that with an increase in the mole fraction of[HPy][BF_(4)],the self-diffusion coefficient ***,the excess molar volume initially decreases,reaches a minimum,and then *** rules of radial distribution functions(RDFs)of characteristic atoms are *** increasing the mole fraction of[HPy][BF_(4)],the first peak of the RDFs of HA1-F decreases,while that of CT6-CT6 rises at first and then *** indicates that the solvent molecules affect the polar and non-polar regions of[HPy][BF_(4)]differently.

关键词： Pyridinium ionic liquids Thermodynamic properties Molecular dynamics simulation Radial distribution functions

Size focusing of colloidal quantum dots under high monomer concentration

在线全文

学校读者我要写书评

暂无评论

Nano Research 2022年第8期15卷 7622-7630页

作者： Huiyan liu zhi liu Chaodan Pu School of Physical Science and Technology ShanghaiTech UniversityShanghai 201210China

The diffusion-controlled growth mode is widely used to narrow the size distribution of colloidal quantum ***,this growth mode always suffers from size broadening at the later growth *** monitoring the growth process of CdS colloidal quantum dots,we show the size broadening is a result of different growth rates of CdS colloidal quantum dots(CQDs)with different *** concentration-dependent growth experiments demonstrate the different growth rates are caused by the different ligand permeabilities of CdS *** cubic ones have lower ligand permeability but higher saturated surface reaction rate than the noncubic ones,leading to unexpected narrower size distribution under higher monomer *** efficient narrowing can be obtained by the addition of chloride ions,which can increase the ligand permeability of all CdS CQDs,as well as the opposite discrepancies in ligand permeability and surface reaction between cubic and noncubic CdS *** photoluminescence(PL)full width at half maximum(FWHM)of CdS CQDs can be narrowed down to below 80 meV for PL peaks from 430 to 500 *** the inevitable usage of the ligands in the solution synthesis of colloidal nanocrystals,the influence of morphology difference on growth rate should be *** results can provide an alternative solution to realize size focusing for the synthesis of colloidal nanocrystals.

关键词： CdS quantum dots surface reaction monomer diffusion ligand permeability

Temperature Responsive 3D Structure of Rod-like Bionanoparticles Induced by Depletion Interaction

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

Chinese Journal of Polymer Science 2014年第10期32卷 1271-1271,1272-1275页

作者： zhi liu 牛忠伟 National Research Centre of Engineering Plastics Technical Institute of Physics and ChemistryChinese Academy of Sciences University of Chinese Academy of Sciences

Herein, we show that rod-like tobacco mosaic virus （TMV） can self-assemble into 3D bundled structures in aqueous solution using azobenzene modified Pluronics F127 block copolymers （Azo-F127） to induce depletion. The structures are characterized by both transmission electron microscopy and dynamic light scattering. The self-assembly process can be controlled reversibly by temperature. The formation of Azo-F127 hard spheres during the self-assembly is the main cause of this phenomenon.

关键词： Tobacco mosaic virus Pluronics Depletion interaction Self-assembly.

Fuzzy adaptive tracking control within the full envelope for an unmanned aerial vehicle

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Aeronautics 2014年第5期27卷 1273-1287页

作者： liu zhi Wang Yong Department of Automation Science and Electrical Engineering Beihang University

Motivated by the autopilot of an unmanned aerial vehicle（UAV） with a wide flight envelope span experiencing large parametric variations in the presence of uncertainties, a fuzzy adaptive tracking controller（FATC） is proposed. The controller consists of a fuzzy baseline controller and an adaptive increment, and the main highlight is that the fuzzy baseline controller and adaptation laws are both based on the fuzzy multiple Lyapunov function approach, which helps to reduce the conservatism for the large envelope and guarantees satisfactory tracking performances with strong robustness simultaneously within the whole envelope. The constraint condition of the fuzzy baseline controller is provided in the form of linear matrix inequality（LMI）, and it specifies the satisfactory tracking performances in the absence of uncertainties. The adaptive increment ensures the uniformly ultimately bounded（UUB） predication errors to recover satisfactory responses in the presence of uncertainties. Simulation results show that the proposed controller helps to achieve high-accuracy tracking of airspeed and altitude desirable commands with strong robustness to uncertainties throughout the entire flight envelope.

关键词： Flight control systems Full flight envelope Fuzzy adaptive tracking control Fuzzy multiple Lyapunov function Fuzzy T–S model Single hidden layer neural network

Late-model Ionic Clusters of KNO_3 and Their Configurations

在线全文

学校读者我要写书评

暂无评论

Chemical Research in Chinese Universities 2005年第5期21卷 587-591页

作者： SHI Lei YANG zhi liu zhi-qiang liu Shu-ying School of Public Health Jilin University Changchun 130021 P. R. China Changchun Institute of Applied Chemistry Chinese Academy of Sciences Changchun 130022 P. R. China

Late-model ionic clusters of KNO3 were formed under the conditions of electrospray ionization. A series of peaks of the ionic clusters could be observed in the electrospray ionization mass spectra（ESIMS）. The general formulae of the ionic clusters were deduced to be K^ ＋（ KNO3 ） m and NO3^-（ KNO3 ）m. By referring to the crystal structure of KNOs , the possible configurations of these new typical ionic clusters were speculated based on the calculated data by means of the Gaussian-94^x computer program.

关键词： Cluster KNO3 Configuration Gaussian-94^* computer program

NUMERICAL SIMULATION OF PROPAGATION AND BREAKING PROCESSES OF A FOCUSED WAVES GROUP

在线全文

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2012年第3期24卷 399-409页

作者： HUANG Zong-liu LIN Peng-zhi State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan University Chengdu 610065China

A two-dimensional numerical wave flume is developed to study the focused waves group propagation and the consequent breaking processes. The numerical model is based on the Reynolds-Averaged Navier-Stokes （PANS） equations, with the standard k - c turbulence model to simulate the turbulence effects. To track the complicated and broken free-surface, the Volume Of Fluid （VOF） method is employed. The numerical model combines the ＂Partial Cell Treatment （PCT）＂ method with the ＂Locally Relative Stationary （LRS）＂ concept to treat the moving wave paddle so that various waves can be generated directly in a fixed Cartesian grid system. The theoretical results of the linear and nonlinear waves are used to validate the numerical wave flume firstly, and then a plunging breaking wave created by a focused waves group is simulated. The numerical results are compared to the experimental data and other simulation results, with very good agreements. The turbulence intensity, the flow field and the energy dissipation in the breaking processes are analyzed based on the numerical results. It is shown that the present numerical model is efficient and accurate for studying the waves group generation, the waves packet propagation, and the wave breaking processes.

关键词： focused waves group plunging breaking Volume Of Fluid (VOF) k - ε turbulence model irregular wave maker

Influence of the Spudcan Angle on the Ultimate Bearing Capacity of Jack-up Platform

在线全文

学校读者我要写书评

暂无评论

China Ocean Engineering 2018年第4期32卷 476-481页

作者： ZHANG Qi-yi liu zhi-jie Department of Ocean Engineering College of EngineeringOcean University of ChinaQingdao 266100China Key Laboratory of Ocean Engineering of Shandong Province Qingdao 266100China

Jack-up platforms of the Ocean engineering structures always withstand the vertical gravity loads which are applied to the seabed by spudcan, so it is important to determine the bearing capacity and the penetration depth of the spudcan for its geometry. In fact, it is up to the deformation law and the failure modes of soil surrounding the spudcan which can calculate the ultimate bearing capacity of the spudcan foundation on the soil seabed. By using the finite element analysis software Abaqus, the deformation law of soil around the spudcan is analyzed in detail, and the failure modes of soil surrounding the spudcan foundation are achieved. At the same time, based on the limit equilibrium theory, by use of static permissible slip-line field, the ultimate bearing capacity of the spudcan foundation is analyzed and the lower limit solution is derived theoretically, and the effect of the spudcan angle on the ultimate bearing capacity is investigated. The numerical results are compared with those obtained by the theoretical formulas deduced in this paper. On the basis of the lower limit solutions in this paper, the effect of the spudcan angle on the ultimate bearing capacity is revealed, and a practical bearing capacity formula is given to take the effect of the spudcan angle into consideration.

关键词： spudcan lower limit analysis ultimate bearing capacity failure modes Abaqus

Influence of Prior Austenite Deformation and Non-Metallic Inclusions on Ferrite Formation in Low-Carbon Steels

在线全文

学校读者我要写书评

暂无评论

Journal of Iron and Steel Research International 2010年第6期17卷 36-42页

作者： ZHANG Chi XIA zhi-xin YANG zhi-gang liu zhi-hao Department of Materials Science and Engineering Tsinghua University Beijing 100084 China

Effects of prior austenite deformation and non-metallic inclusions on the ferrite nucleation and grain refine- ment of two kinds of low-carbon steels have been studied. The ferrite nucleation on MnS and V（C, N） is observed. The combination of thermomeehanical processes with adequate amounts of non-metallic inclusions formed in low-car- bon steels could effectively refine the grain size and the microstructure. Ferrite nucleated on the single MnS or V（C, N） inclusions and complex MnS＋V（C,N） inclusion. The proper addition of elements S and V could effectively promote the formation of ferrite and further refinement of ferrite grains.

关键词： austenite deformation non-metallic inclusion ferrite nucleation low-carbon steel

Regional Stability of Positive Switched Linear Systems with Multi-equilibrium Points

在线全文

学校读者我要写书评

暂无评论

International Journal of Automation and computing 2017年第2期14卷 213-220页

作者： zhi liu Yu-Zhen Wang School of Control Science and Engineering Shandong University Ji'nan 250061 China

This paper studies the regional stability for positive switched linear systems with multi-equilibrium points （PSLS-MEP）. First, a sufficient condition is presented for the regional stability of PSLS-MEP via a common linear Lyapunov function. Second, by establishing multiple Lyapunov functions, a dwell time based condition is proposed for the regional stability analysis. Third, a suprasphere which contains all equilibrium points is constructed as a stability region of the considered PSLS-MEP, which is less conservative than existing results. Finally, the study of an illustrative example shows that the obtained results are effective in the regional stability analysis of PSLS-MEP.

关键词： Regional stability positive switched linear system multi-equilibrium points common linear Lyapunov function multipleLyapunov function.

Automatic pattern acquisition from game records in GO

在线全文

学校读者我要写书评

暂无评论

The Journal of China Universities of Posts and Telecommunications 2007年第1期14卷 100-105页

作者： liu zhi-qing DOU Qing School of Software Engineering Beijing University of Posts and Telecommunications Beijing 100876 China

Computer programs of GO are typically constructed using a knowledge-based approach with heuristics and pattern matching because of enormous complexities of the game. In this approach, quantity, quality, and consistency of patterns used in computer programs of GO to a large extent determine the strengths of the programs. This study presents an effective method to acquire automatically comprehensive GO patterns from large collections of game records. Statistical usages of the patterns ensure consistency and quality of the patterns, which in turn can help improve the strengths of computer GO programs. Additionally, statistical usages of patterns from different sources of game records clearly show subtle and significant discrepancies among various types of GO players, and clarify certain myths in the playing of GO.

关键词： computer games automatic knowledge acquisition,spatial patterns recognition