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Evaluating Wealth Management Centers in the Pearl River Delta by Using Principal Component Analysis
Weijun Xu,Shaoying Huang,Zhiqiang Wang 보안공학연구지원센터 2015 International Journal of Smart Home Vol.9 No.12
Because of the rapid development and wealth accumulation in the Pearl River Delta (PRD), most of the cities in this area are motivated to establish wealth management centers (WMCs). We create an evaluation index system for assessing the development level of WMCs in cities in the PRD; we develop this system by selecting 20 indicators including gross regional production (GDP). Subsequently, we use panel data from 2010 to 2013 of nine cities in the PRD to evaluate the financial competitiveness of each of these cities through principal component analysis (PCA); we further analyze the pioneering roles of Guangzhou and Shenzhen in establishing WMCs in the PRD. The numerical analysis results reveal that Shenzhen and Guangzhou rank first and second, respectively, regarding financial competitiveness in the PRD, indicating that the two cities play a leading role in the establishment of WMCs in the PRD.
Weijun Fu,Feng-juan Xu,Wen-bo Guo,Mei Zhu,Chen Xu 대한화학회 2013 Bulletin of the Korean Chemical Society Vol.34 No.3
An efficient synthesis of 3-halofurans by the intramolecular cyclization of 2-(1-alkynyl)-2-alken-1-ones with cupric halide has been developed. A broad range of 3-chloro- and 3-bromofuran derivatives could be obtained in the present method in moderate to good yields. The 3-halofuran derivatives are potential synthetic intermediates for amplification of molecular complexity.
Influence of Gas Content on Performance Effect on Shunt Vane Type Aviation Fuel Pump
Zixuan Xu,Zhenggui Li,Weijun Wang,Qifan Wang,Yang Xu,Yibin Li 한국유체기계학회 2022 International journal of fluid machinery and syste Vol.15 No.1
In order to study the flow law of shunt vane type aviation fuel pump under the condition of gas-liquid mixture transportation, based on the RNG K-ε turbulence model and the Euler-Euler non-uniformity model, using the ANSYS CFX software to calculate an aviation fuel pump under different gas content conditions, and analyzing the flow of the fuel pump and the pressure law of the blade pressure. The research shows that the gas phase is mainly distributed in the front section of the long blade suction surface and the back section of the short blade pressure surface. The increased gas content will result in increased liquid velocity in the pump, which makes the gas phase gradually develop towards the suction surface of long and short blades and diffuse to the impeller flow path. The gas content mainly affects the pressure surface load of the fuel pump blades. The pressure load curve fluctuates at the relative position of the short blade (0.5-0.6) and long blade (0.3-0.6) as well as at the end of the blade and decreases with the increase in gas content. The change of pressure fluctuation of the blade is mainly reflected at the junction of long and short blades, and the pressure fluctuation amplitude of the front section of the short blade and middle section of the long blade fluctuates greatly. With the increase in gas content, the pressure fluctuation amplitude at each monitoring point reduces. The research results can provide some reference for the design of aviation fuel pumps.
Hongkai Guo,Hu Xu,Chengwen Zhao,Xiangzhong Hao,Ziyuan Yang,Weijun Xu 한국공업화학회 2022 Journal of Industrial and Engineering Chemistry Vol.108 No.-
Achieving high catalytic performance with the lowest cost possible cathode material is critical for electrocatalyticsynthesis of H2O2 by oxygen reduction reaction. In this work, we describe a method ofpreparing highly active yet stable graphite felt electrocatalysts containing ultrahigh-loading oxygen contentby using organic acid anodic modification. The results show that modified graphite felt surface wasmore hydrophilic and introduced a large amount of defect sites and oxygen-containing groups. Moreover,the influence of mass oxalic/citric acid ratio and oxidation time of graphite felt cathode were investigated. As a result, H2O2 electrogeneration was 1.6 times as much as that of virgin graphite felt counterpart at themass oxalic/citric acid ratio of 2:1 oxidation for 40 min. However, overoxidation also impaired the electricalproduction of H2O2 due to decarboxylation. Finally, the effect of cathode potential and reaction pHon graphite felt cathode was optimized. As for the modified graphite felt, the maximum accumulationrate of H2O2 reached 4.5 mg h1 cm2 at the conditions of 0.85 V (SCE), 0.4 L min1 O2 flow rate andpH = 3. In addition, it kept a stable performance for electrochemical generation of H2O2 during 8 cycles.
Research of high response control technology of a moving coil electromechanical converter
Gong Zhang,Zheng Xu,Weijun Wang,Zhichen Hou,Xing Gu,Ning Lin,Liangwei Luo,Jing Huang 제어로봇시스템학회 2016 제어로봇시스템학회 국제학술대회 논문집 Vol.2016 No.10
Electromechanical converters (EMCs) are regarded as the most widely employed linear motion mechanism in various industry driving fields. This study tries to improve the characteristics deficiency of a moving coil electro-mechanical converter (MC-EMC), such as the output electromagnetic force, response time and response speed, and based on the time constant and currents are effected by inductance and resistance of the transformation coils, the carrying current coils of MC-EMC are adopted a transformation of segmentation and combination. The mathematical model and simulation for the response time, displacement, output electromagnetic force, acceleration of MC-EMC are proposed respectively. Results show that compared coils in parallel divided into three sections with coils in single group, the displacement step response time is reduced from 14.6㎳ to 9.94㎳ the response speed is over doubled, and electromagnetic force is raised about 8 times, the acceleration is increased by 8.7 times, the peak response time is reduced about 0.5 times, which means the design MC-EMC could realize the performance of short response time and high electromagnetic force, and display good prospects.
Interaction Matrix Based Analysis and Asymptotic Cooperative Control of Multi-agent Systems
Zhicheng Hou,Jianxin Xu,Gong Zhang,Weijun Wang,Changsoo Han 제어·로봇·시스템학회 2020 International Journal of Control, Automation, and Vol.18 No.5
In this paper, we investigate a decentralized asymptotic cooperative control problem of multi-agent systems with leader-follower configuration. We firstly develop a new method using a proposed “interaction matrix” for the analysis of cooperation convergence of multi-agent systems, i.e. both consensus of the agents states and trajectory tracking of the whole group can be instantaneously concluded only by observing the minimum eigenvalue of the interaction matrix. For a multi-agent system, the external given desired trajectory can be partially obtained (through sensing or detecting) by the leaders, but higher-order derivatives such as acceleration and jerk of the desired trajectory cannot be obtained. In this case, by using some conventional control methods, the trajectory tracking performance is always not satisfactory when a trajectory varies aggressively w.r.t. time. For the sake of asymptotic tracking of an arbitrary given external trajectory of a multi-agent system, we develop a nonlinear cooperative controller based on the robust integral of signum of cooperative error (RISCE) technique, where the interaction matrix is used. The simulation results show asymptotic convergence of cooperation by using the proposed control, and better performance compared to composited nonlinear feedback based PD (CNF-PD) control.