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Analysis of the Internal Characteristics of a De ector Jet Servo Valve

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Chinese Journal of Mechanical Engineering 2019年第2期32卷 180-192页

作者： Hao Yan Yukai Ren Lei Yao lijing Dong School of Mechanical Electronic and Control Engineering Beijing Jiaotong University

In current research on deflector jet servo valves, the receiver pressure estimated using traditional two-dimensional simulation and theoretical calculation is always lower than the experimental data; therefore, credible information about the flow field in the prestage part of the valve can hardly be obtained. To investigate this issue and understand the internal characteristics of the deflector jet valve, a realistic numerical model is constructed and a three-dimensional simulation carried out that displays a complex flow pattern in the deflector jet structure. Then six phases of the flow pattern are presented, and the defects of the two-dimensional simulation are revealed. Based on the simulation results, it is found that the jet in the deflector has a longer core area and the fluid near the shunt wedge cannot resist the impact of the high-speed fluid. Therefore, two assumptions about the flow distribution are presented by which to construct a more complete theoretical model. The receiver pressure and prestage pressure gain are significantly enhanced in the calculations. Finally, special experiments on the prestage of the servo valve are performed, and the pressure performance of the numerical simulation and the theoretical calculation agree well with the experimental data. Finally, the internal mechanism described by the theoretical and numerical models is verified. From this research,more accurate numerical and theoretical models are proposed by which to figure out the internal characteristics of the deflector jet valve.

关键词： Deflector jet Servo valve Computational fluid dynamics(CFD) Numerical simulation

幼儿园教师的儿童户外运动安全规范能力体系构建

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幼儿教育 2024年第36期 21-26页

作者：杜丽静杨晓露绍兴文理学院教师教育学院浙江绍兴312000 ²延安大学西安创新学院教育学院陕西西安710100

本研究采用模糊德尔菲法构建了包括4个一级指标(教师事故预防、教师环境规划、教师活动实施、教师意外事件应急处置)、12个二级指标和44个三级指标的3-6岁儿童户外运动安全规范指标体系并确立权重,丰富了我国幼儿园教师的儿童户外运动... 详细信息

本研究采用模糊德尔菲法构建了包括4个一级指标(教师事故预防、教师环境规划、教师活动实施、教师意外事件应急处置)、12个二级指标和44个三级指标的3-6岁儿童户外运动安全规范指标体系并确立权重,丰富了我国幼儿园教师的儿童户外运动安全规范能力体系相关研究。

关键词： 3-6岁儿童户外运动幼儿园教师安全规范能力模糊德尔菲法

Surrounding Problem of Multi-agent Systems Under Arbitrary Topology

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Chinese Journal of Electronics 2020年第4期29卷 750-758页

作者： LIU Weifeng RU Xinfeng WEN Chenglin DONG lijing School of Automation Hangzhou Dianzi University School of Mechanical Electronic and Control Engineering Beijing Jiaotong University

This paper studies surrounding dynamically multi-targets with second-order integrator/nonlinear systems and continuous time-varying *** continuous time-varying topology refers to the continuous change of the topology rather than switching in several fixed *** multi-targets is an extension of containment *** distributed control algorithm is designed based on the containment control *** transforming the system of containment control into error stability, the condition that the error between multi-agent systems and multi-targets to be constant can be obtained by using the algebraic graph theory, matrix theory and Lyapunov function stability *** multiagent systems can dynamically surround multi-targets by designing the deviation ***, simulation experiments verify the effectiveness of the proposed algorithm.

关键词： Continuous time-varying topology Containment control Second-order integrator/nonlinear systems

Improving seeking precision by utilizing ghost imaging in a semi-active quadrant detection seeker

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Chinese Journal of Aeronautics 2021年第12期34卷 171-176页

作者： Siyuan WANG lijing LI Wen CHEN Mingjie SUN Department of Opto-electronic Engineering Beihang UniversityBeijing 100083China

Conventional semi-active laser guidance takes advantage of the laser designator to illuminate the stable and uniform laser spot on target *** seeker collects the reflected light by a quadrant detector and outputs the relative position information to guide the missile to the illuminating laser ***,the designation and guidance accuracy could be jeopardized by the randomly drifting of laser spot caused by the instability of designation platform and air *** this work,ghost imaging technique is adapted to a quadrant detector semi-active seeker by utilizing structured illumination on the *** a series of structured illumination masks,the signals from the quadrant detector are multiplexed to perform calculation of the target relative position as well as image reconstruction of the illuminated area *** target recognition methods could be further applied to the reconstructed image to calculate the designating error and correct the *** results of simulation and experiment demonstrate that the proposed method could improve the guidance accuracy in many circumstances which would lead to attacking deviation if conventional semi-active laser guidance is used.

关键词： Digital micro-mirror device Ghost imaging Guidance system Image acquisition Semi-active laser seeker

A General and Highly Selective Method for the Asymmetric Synthesis of Trifluoromethyl-Substituted α- and β-Aminophosphonates

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Chinese Journal of Chemistry 2013年第7期31卷 892-900页

作者： lijing Wang Qilong Shen Long Lu Key Laboratory of Organofluorine Chemistry Shanghai Institute of Organic Chemistry Chinese Academy of Sciences Shanghai 200032 China

A highly selective method for the asymmetric formation of trifluoromethyl-substituted α- and β-aminophos- phonates was described. The reaction proceeded with high yields and good to excellent diastereoselectivity. T... 详细信息

关键词： trifluoromethyl aminophosphonate asymmetric fluorine

A field experimental study of lignin sand stabilizing material(LSSM) extracted from spent-liquor of straw pulping paper mills

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Journal of Environmental Sciences 2005年第4期17卷 650-654页

作者： WANGHan-jie lijing LUXiao-zhen JINYong-can LaboratoryofRegionalClimate-EnvironmentResearchforTemperateEastAsia InstituteofAtmosphericPhysicsChineseAcademyofSciencesBeijing100085China NanjingForestry UniversityNanjing210037China

A new technique was introduced for sand stabilization and re-vegetation by use of lignin sand stabilizing material(LSSM). LSSM is a reconstructed organic compound with lignin as the most dominant component from the extracts of black-liquor issued by straw pulp paper mills. Unlike the polyvinyl acetate or foamed asphalt commonly used for dune stabilization, the new material is plant-friendly and can be used with virescence actions simultaneously. The field experimental study was conducted since 2001 in China's Northwest Ningxia Hui Autonomous Region and has been proved that LSSM is effective in stabilizing the fugitive dunes, making the arenaceous plants survive and the bare dune vegetative. The advisable solution concentration is 2% and the optimal field spraying quantity is 2 5 L/m^2 The soil nutrients of the stabilized and greened dune, such as organic matter, available phosphorous and total nitrogen are all increased compared with the control treatment, which is certainly helpful to the growth of arenaceous plants. The technique is worthwhile to be popularized because it is provided not only a new method for desertification control but also an outlet for cleaning contaminants issued from the straw paper mills.

关键词： experimental study lignin sand stabilizing material(LSSM) black-liquid straw pulp paper mills

Transport for Stochastic System with Infinite Locally Coupled Oscillators

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Communications in Theoretical Physics 2003年第3X期40卷 305-310页

作者： ZHAOYing-Kui lijing-Hui ZHAOXian-Geng GraduateSchoolofChinaAcademyofEngineeringPhysics P.O.Box2101Beijing100088China CenterforNonlinearStudies InstituteofAppliedPhysicsandComputationalMathematicsP.O.Box8009(28)Beijing100088China

We consider the transport of particles for spatially periodic system with infinite locally coupled oscillators dirven by additive and multiplicative noises.A formula of the probability current derived by us shows that the coupling among the infinite oscillators is an ingredinent for *** coupling of the oscillators can induce transport of particles in the absence of the correlation of the additive and multiplicative noises,even without the multiplicative noise.

关键词：随机系统粒子输运空间周期系统粒子动力学耦合振荡附加噪音乘性噪音

Selective laser melting of Al–8.5Fe–1.3V–1.7Si alloy: Investigation on the resultant microstructure and hardness

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Chinese Journal of Aeronautics 2015年第2期28卷 564-569页

作者： Zheng lijing Liu Yingying Sun Shaobo Zhang Hu School of Materials Science and Engineering Beihang University

This article presents the microstructure and hardness variation of an Al 8.5Fe-1.3V 1.7Si （wt%, FVS0812） alloy after selective laser melting （SLM） modification. Three zones were distinguished across the melting pool of the SLM-processed FVS0812 alloy： the laser melted zone （LMZ）, the melting pool border, and the heat affected zone （HAZ） in the previously deposited area around the melting pool. Inside the LMZ, either an extremely fine cellular-dendritic structure or a mixture zone of the α-Al matrix and nanoscale Al12（Fe,V）3Si particles appeared. With a decreased laser beam scanning speed, the cellular-dendritic structure zone within the LMZ shrank significantly while the mixture zone expanded. The α-Al and Al12（Fe,V）3Si mixture zone was also observed in the HAZ, but another phase, submicron θ-Al13Fe4 particles with rectangular or hexagonal shapes, formed along the melting pool border. Microhardness tests indicated that the hardness of the SLM-processed FVS0812 samples far exceeded that of the as-cast FVS0812 alloy.

关键词： Al-Fe-V-Si alloys Hardness Melting pool Microstructure Selective laser melting

New Bulb Turbine with Counter-rotating Tandem-runner

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Chinese Journal of Mechanical Engineering 2012年第5期25卷 919-925页

作者： HAN Fengqin YANG lijing YAN Shijie KUBOAT Takashi College of Electric Power South China University of Technology Guangzhou 510640 China Guangdong Technical College of Water Resources and Electric Engineering Guangzhou 510635 China

With the increasing demand for the clean sustainable power, the turbine design urgently turns to increase the capability significantly toward higher head for generating larger power. Currently, there are many studies in the field of the bulb turbine with single-stage runner, though reports about counter-rotating tandem-runner are rare. However, the further high-head application with the single-stage runner is very difficult to achieve due to the limit of the specific speed. In this paper, a new bulb turbine with the tandem-runner is designed in order to substantially increase the applicable limit toward higher head with larger power. A half of the net head is absorbed by the frontal runner which can generate output power, while the remaining half is absorbed by the rear runner. To generate the Euler energy required for the rear runner, the frontal runner has the counter-rotation against the rear runner so that the counter-rotating tandem-runner can meet the purpose of double head and power under the same size as the conventional bulb turbine. Supply and demand of Euler energy between the two runners are thoroughly optimized through the detailed flow analysis, in order to secure the stable operation. As a result, the interference of Euler energies between the outflow from the frontal runner and the inflow to the rear runner is confirmed to be very small on the counter-rotating interface between the two runners. The prediction method of on-cam performance between the two adjustable runners is also developed numerically, which provides optimal flow between the two runners. This research provides a theoretical basis for the optimal design and operation of the counter-rotating tandem-runner bulb turbines.

关键词： bulb turbine tandem-runner counter-rotating Euler energy power increase