检索结果-南通市图书馆

Dimensionless study on outlet flow characteristics of an air-driven booster

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) 2012年第6期13卷 481-490页

作者： Yan SHI mao-lin CAI School of Automation Science and Electrical Engineering Beihang UniversityBeijing 100191China

Air-driven boosters are widely used to obtain high-pressure gas. Through analysis of the boosting process of an air-driven booster, the basic mathematical model of working processes can be set up. By selecting the appropriate reference values, the basic mathematical model is transformed to a dimensionless expression. Using MATLAB/Simulink for simulation and studying the booster experimentally, the dimensionless outlet flow characteristics of the booster were obtained and the simulation results agree well with the experimental results. Through analysis, it can be seen that the dimensionless outlet flow of the booster is mainly determined by the dimensionless input pressure of the driving chamber, the dimensionless outlet condition pressure of the booster and the dimensionless area of the piston in the driving chamber. The dimensionless average outlet flow becomes larger with an increasing dimensionless input pressure of the driving chamber, but it becomes smaller with an increase in the dimen- sionless outlet condition pressure of the booster. Especially when the dimensionless outlet condition pressure is approximately 1.4, the dimensionless average outlet flow reaches zero. With an increase in the dimensionless area of the piston in the driving chamber, the dimensionless average outlet flow increases and peaks at approximately 1.89, and after this peak, it starts to decrease. This research can be referred to in the design of air-driven boosters.

关键词： Air-driven booster Outlet flow Pneumatic system Compressed air

On the stochastic dynamics of molecular conformation

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) 2007年第9期8卷 1401-1407页

作者： DENG mao-lin ZHU Wei-qiu Department of Mechanics State Key Laboratory of Fluid Power Transmission and Control Zhejiang University Hangzhou 310027 China

An important functioning mechanism of biological macromolecules is the transition between different conformed states due to thermal fluctuation. In the present paper, a biological macromolecule is modeled as two strands with side chains facing each other, and its stochastic dynamics including the statistics of stationary motion and the statistics of conformational transition is studied by using the stochastic averaging method for quasi Hamikonian systems. The theoretical results are confirmed with the results from Monte Carlo simulation.

关键词： Biological macromolecule Thermal fluctuation Stationary statistics Transition time Stochastic averaging method

Synthesis and Crystal Structure of Tetraaquacopper(II) Bis(5-fluorouracil-1-acetate) Tetrahydrate

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Structural Chemistry 2006年第5期25卷 562-566页

作者： WANG Wei-Dong HU mao-lin Hubei Key Laboratory of Bioanalytical Technique Hubei Normal University Huangshi Hubei 435002 China Department of Chemistry and Environmental Engineering Hubei Normal University Huangshi Hubei 435002 China School of Chemistry and Materials Science Wenzhou University Wenzhou 325027 China

The title compound, [Cu（C6H4N2O4F）2（H2O）4].4（H2O） I, has been hydrothermally synthesized and structurally determined by single-crystal X-ray diffraction method. It crystallizes in monoclinic, space group P21/c with a = 8.3041（17）, b = 12.045（2）, c = 11.077（2） A, β = 92.567（3）°, V= 1106.8（4） A^3, Mr = 581.89, Z= 2, Dc = 1.746 g/cm^3, F（000） = 598,μ（MoKa） = 1.090 mm^-1, the final R = 0.0296 and wR = 0.0806 for 3195 observed reflections with Ⅰ 〉 2σ（Ⅰ）. In the centrosymmetric compound I, each Cu（Ⅱ） ion is coordinated by six O atoms from two 5-fluorouracil-1-acetate anions and four water molecules, forming a six-coordinated octahedral environment. N-H…O and O-H…O hydrogen-bonding interactions are observed in the structure, leading to the formation of a three-dimensional network.

关键词： copper crystal structure 5-fluorouracil-1-acetate

Hydrothermal Synthesis and Crystal Structure of a Novel Polymolybdic(VI) Acid: {[H_3O]_2^+[Mo_2O_4(OH)_6]^(2-)}_n

在线全文

学校读者我要写书评

暂无评论

Chinese Journal of Structural Chemistry 2006年第6期25卷 653-656页

作者： WANG Wei-Dong HU mao-lin Hubei Key Laboratory of Bioanalytical Technique Hubei Normal University Huangshi Hubei 435002 China Department of Chemistry and Environmental Engineering Hubei Normal University Huangshi Hubei 435002China School of Chemistry and Materials Science Wenzhou University Wenzhou Zhejiang 325027 China

A novel supramolecular polymolybdic（VI） acid was unexpectedly synthesized by the reaction of sodium molybdate with 1,2,4,5-benzenetetracarboxylic and trichloroacetic acids in 1：1：1 molar ratio under hydrothermal condition. The crystal belongs to tetragonal with space group P4/mbm, a = 0.88867（17）, b = 0.88867（17）, c = 0.55676（15） nm, Z = 3, V = 0.43969（17） nm^3, Dc = 4.486 g/cm^3,μ = 4.365 mm^-1, F（000） = 576, R = 0.0273 and wR = 0.0679. In the crystal, the Mo（VI） atoms are six- and five-coordinated in distorted octahedral and trigonal bipyramidal geometries, respectively. Furthermore, these Mo（VI） atoms, bearing different coordinated environments, are bridged by OH groups with disorder O atoms to form a twodimensional framework with pentagonal grids. It is worthy of notice that these adjacent twodimensional frameworks are extended into a three-dimensional supramolecular array with pentagonal large cavities＇by Van Der Waals＇ forces and hydrogen bonding interactions.

关键词： polymolybdic acid hydrothermal synthesis crystal structure two-dimensional framework

Investigation on plume interference effect of solid propellant micro-thruster

在线全文

学校读者我要写书评

暂无评论

航空动力学报 2011年第9期26卷 2027-2031页

作者： ZHANG Bin mao Gen-wang HU Song-qi CHEN mao-lin （National Key Laboratory of Combustion Flow and Thermo-Structure College of Astronautics Northwestern Polytechnical University Xi＇an 710072 China

The three-dimensional numerical simulation of two-phase plume flow of solid propellant micro-thrusters was *** it was used to investigate the plume interference effect by combining the direct simulation Monte Carlo(DSMC) method for multi-component gas flow with the two-way coupling model for two-phase rarefied *** different space between the two micro-thrusters and different wall temperature,the plume interference effect was analyzed *** results show that under the plume interference effect the gas is compressed and the flow direction is changed,which resulted in the increasing of gas pressure and temperature;solid phase made no significant effect on the flow parameters of gas phase;with the rising of the space between the two micro-thrusters,the maximum pressure decreased and the maximum temperature increased in the domain under the plume interference effect;the wall temperature could influence the temperature of the gas which is extremely close to the wall,but not the gas pressure.

关键词： solid propellant micro-thruster plume interference effect two-phase plume flow catalytic decomposition specific impulse

Resveratrol Tetramers from the Roots of Ampelopsis sinica

在线全文

学校读者我要写书评

暂无评论

Chinese Chemical Letters 2001年第10期12卷 893-896页

作者： Na LI Xin LIU mao lin Institute of Materia Medica Chinese Academy of Medical Sciences&Peking Union Medical College1 Xian Nong Tan StreetBeijing 100050

A new resveratrol tetramer, sinicin A was isolated from the roots of Ampelopsis sinica, with four known tetramers: vitisin A, cis-vitisin B, ampelopsin H and hopeaphenol. The structure and stereochemistry of sinicin A... 详细信息

关键词： Ampelopsis sinica Vitaceae resveratrol tetramer

An Energy-Efficient LEACH Algorithm for Wireless Sensor Networks 36

在线全文

学校读者我要写书评

暂无评论

An Energy-Efficient LEACH Algorithm for Wireless Sensor Netw...

Air bubble breakup in shear water flows generated by a plug conduit:An experimental investigation

第36届中国控制会议

作者： lin mao Ying Zhang College of Information Engineering Shanghai Maritime University

ISBN: (纸本)9781538629185

With limited battery power of nodes,communication energy consumption is the main factor to affect the lifetime of wireless sensor *** is of great significance to design a communication protocol to prolong the lifetime of the *** this paper,an energy-efficient LEACH algorithm for wireless sensor networks is proposed,which takes the energy and position factors of each node into account to optimize the cluster head election and data transmission *** method introduces the current energy and position factors of the node into the threshold to further reduce the randomness of the cluster head’s *** the data transmission stage,some of the neighboring cluster heads are dedicated to be selected as the relay nodes to make the communication energy consumption *** simulation results show that the proposed algorithm has higher stability and longer lifetime of the network compared to LEACH and LEACH-C algorithms.

关键词： wireless sensor networks LEACH clustering energy consumption relay nodes

来源： cnki会议评论

在线全文

cnki会议

学校读者我要写书评

暂无评论

Journal of Hydrodynamics 2023年第6期35卷 1077-1088页

作者： Han Wu mao-lin Zhou Wei-lin Xu Wang-ru Wei Jian-bo Li State Key Laboratory of Hydraulics and Mountain River Engineering Sichuan UniversityChengdu610065China PowerChina Chengdu Engineering Corporation Limited Chengdu610072China

In the context of a sudden contraction plug conduit,the near-wall area experiences a significant shearing effect of water flow,however,the extent to which this shearing effect occurs in bubble-water flow and the related variation mechanisms of air bubble size and number remain *** study employs a model test method to investigate the diffusion process of bubble-water flow in a sudden contraction plug *** size and number of bubbles,as well as their distribution along the shearing section under varying initial air volume conditions,are studied in detail using a high-speed image acquisition *** experimental findings reveal a self-similar relationship between the number and size of bubbles and their cross-sectional distribution over *** bubble number and size vary in three stages,i.e.,quasi-suspension,shearing,and shearing completion *** direction perpendicular to the conduit exhibits peak values in bubble number distribution over the three stages,with peak value location varying with the near-wall *** time progresses,the peak value increases,and a larger initial air volume corresponds to a smaller distance of the peak value location from the *** size of air bubbles near the wall is consistent with the minimum diameter of air bubbles in shear flow and is hardly affected by the initial air *** results aid in comprehending the change law of two-phase water and air flow under a strong shearing effect in the plug conduit,and provide useful insights for hydraulic design in fluid engineering.

关键词： Air-water flows bubble properties air diffusion process plug conduits experimental study

An Inequality for the Perron Pair of an Irreducible and Symmetric Nonnegative Tensor with Application

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 the Operations Research Society of China 2017年第1期5卷 65-82页

作者： mao-lin Che Yi-Min Wei School of Mathematical Sciences Fudan UniversityShanghai 200433China School of Mathematical Sciences and Shanghai Key Laboratory of Contemporary Applied Mathematics Fudan UniversityShanghai 200433China

The main purpose of this paper is to consider the Perron pair of an irreducible and symmetric nonnegative tensor and the smallest eigenvalue of an irreducible and symmetric nonsingular *** analyze the analytical property of an algebraic simple eigenvalue of symmetric *** also derive an inequality about the Perron pair of nonnegative tensors based on plane stochastic *** finally consider the perturbation of the smallest eigenvalue of nonsingular M-tensors and design a strategy to compute its smallest *** verify our results via random numerical examples.

关键词： Nonnegative tensor Symmetric tensor Irreducible tensor M-Tensor H-Eigenpair An algebraic simple eigenvalue The Perron pair The smallest eigenvalue Perturbation