Recovery of zinc and iron from high iron-bearing zinc calcine by selective reduction roasting

Junwei Han,Wei Liu,Wenqing Qin,Bing Peng,Kang Yang,Yongxing Zheng 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.22 No.-

A novel method to recover zinc and iron from high iron-bearing zinc calcine by reduction roasting-lowacid leaching-magnetic separation was proposed. The effects of roasting and leaching conditions wereinvestigated and their optimum conditions were established. Meanwhile, the mineralogical changesduring the processes were characterized by XRD, VSM, SEM and LPSA. The results show the ZnFe2O4 inthe calcine was decomposed into ZnO and Fe3O4, and about 92.6% Zn was extracted from the roastedcalcine with reporting most of iron as magnetite into the residue. Finally, more than 90% Fe wasrecovered from the residue by magnetic separation method.

Structure-activity correlations of LiNO3/Mg4AlO5.5 catalysts for glycerol carbonate synthesis from glycerol and dimethyl carbonate

Zhenmin Liu,Junwei Wang,Mao-qing Kang,Ning Yin,Xin-kui Wang,Yisheng Tan,Yulei Zhu 한국공업화학회 2015 Journal of Industrial and Engineering Chemistry Vol.21 No.1

MgAl hydrotalcite synthesized via co-precipitation method from magnesium and aluminum nitrateswas calcined to produce Mg4AlO5.5 mixed oxides. The oxides were modified by introducing LiNO3 andapplied to the synthesis of glycerol carbonate from glycerol and dimethyl carbonate. The research resultsindicated that LiNO3/Mg4AlO5.5 was an efficient catalyst for the synthesis of glycerol carbonate. The fullconversion of glycerol and 96.28% yield of glycerol carbonate were obtained after reacting at 80 8C for1.5 h in the presence of LiNO3/Mg4AlO5.5. The structure and properties of the catalysts were studied bymeans of XRD, TGA, BET, CO2-TPD and Hammett indicator method. It was found that the basic strengthand the basicity of the catalysts were enhanced after addition of LiNO3. Over Mg4AlO5.5 oxides, LiNO3 waseasily converted to LiAlO2 which constituted new strong basic sites. Too high basic strength and basicityof catalysts may improve the conversion of glycerol at the cost of GC selectivity reduction.

Solution and Estimate to the Angular Velocity of INS Formed only by Linear Accelerometers

Wu Junwei,Liu Jinfeng,Zhang Yunan,Yuan Na 한국항해항만학회 2006 한국항해항만학회 학술대회논문집 Vol.1 No.-

At present, most efforts tend to develop a INS which is only based linear accelerometers, because of the low cost micro-machining gyroscopes lack of the accuracy needed for precise navigation application and possible achieving the required levels of precise for micro-machining accelerometer. Although it was known in theory that a minimum of six accelerometers are required for a complete description of a rigid body motion, and any configuration of six accelerometers (except for a “measure zero” set of six-accelero-meter schemes) will work. Studies on the feasible configuration of GF-INS indicate that the errors of angular velocity resolved from the six accelerometers scheme are diverged with time or have multi solutions. The angular velocity errors are induced by the biases together with the position vectors of the accelerometers, therefore, in order to treat with the problem just mentioned, researchers have been doing many efforts, such as the extra three accelerometers or the magnetometers may be taken as the reference information, the extended Kalman filter (EKF) involved to make the angular velocity errors bound and be estimated, and so on. In this paper, the typical configurations of GF-INS are introduced; for each type GF-INS described, the solutions to the angular velocity and the specific force are derived and the characteristic is indicated; one of the corresponding extend Kalman filters are introduced to estimate the angular errors; parts of the simulation results are presented to verify the validity of the equations of angular velocity and specific force and the performance of extend Kalman filter.

Maximum Likelihood Recursive Generalized Extended Least Squares Estimation Methods for a Bilinear-parameter Systems with ARMA Noise Based on the Over-parameterization Model

Haibo Liu,Junwei Wang,Yan Ji 제어·로봇·시스템학회 2022 International Journal of Control, Automation, and Vol.20 No.8

Maximum likelihood methods have wide applications in system modeling and parameter estimation. For the purpose of improving the precision of parameter estimation, this paper presents a maximum likelihood recursive generalized extended least squares (ML-RLS) algorithm for a bilinear-parameter system with autoregressive moving average noise based on the over-parameterization identification model. An over-parameterization-based recursive generalized extended least squares algorithm is presented to show the effectiveness of the proposed ML-RLS algorithm for comparison. The simulation test shows that the proposed algorithm has a higher estimation accuracy than the recursive least squares algorithm.

基于UDMISS理论的中国移动医疗APP质量和用户满意度的关系研究

曹峻玮 ( Junwei Cao ),张贵花 ( Guihua Zhang ),刘栋 ( Dong Liu ) 사단법인 아시아문화학술원 2021 인문사회 21 Vol.12 No.3

移动医疗APP近几年在中国快速发展, 特别是随着COVID-19的爆发, 越来越多的人开始通过移动医疗APP在线获取医疗健康服务。本研究以移动医疗APP质量、用户对移动医疗APP熟悉程度为研究视角, 分析了影响用户满意度的因素。基于更新的信息系统成功理论(UDMISS), 考察已有的相关研究, 建立了包括3个维度、4个变量的研究模型, 提出了和研究相关的假设, 并对移动医疗APP用户进行问卷调查, 使用PLS-SEM以及SmartPls3.0对问卷数据进行分析, 对研究模型进行评价, 并且对提出的假设进行了验证。通过本研究期待为移动医疗APP企业的发展和营销提供理论基础和实践指导。 Mobile medical APP have developed rapidly in China in recent years, especially with the explosion of COVID-19, more and more people have started to access medical and health services online through mobile medical APP. This study analyzes the factors affecting user satisfaction by taking the quality of mHealth APP and users’ familiarity with mHealth APP as the research perspective. Based on the updated theory of information system success (UDMISS), the existing related studies were examined, a research model including 3 dimensions and 4 variables was established, hypotheses related to the study were proposed, and a questionnaire survey was conducted on mHealth APP users, and the questionnaire data were analyzed using PLS-SEM and SmartPls3.0 to evaluate the research model, and the proposed The hypotheses were validated. This study is expected to provide theoretical basis and practical guidance for the development and marketing of mobile medical APP companies.

Influence of post-pouring joint on long-term performance of steel-concrete composite beam

Dunwen Huang,Junwei Han,Xiaochun Liu,Shizhuo Zhang,Tao Chen 국제구조공학회 2018 Steel and Composite Structures, An International J Vol.28 No.1

The concrete bridge decks are usually precast and in-situ assembled with steel girders with post-pouring joint in the construction practice of super-wide steel-concrete composite beam. But the difference of concrete age between the precast slabs and the post-pouring joint has been not yet considered for the long-term performance analysis of this kind composite beam. A simply supported precast-assembled T-shaped beam was taken as an example to analyze the long-term performance of steel-concrete composite beam with post-pouring joint. Based on the deformation coordination conditions of the old-new concrete deck and steel girder, a theoretical model for the long-term behavior of precast-assembled composite beam is proposed in this paper according to age-adjusted effective modulus method. Then, the feasibility of the proposed model is verified by the available test data from the Gilbert's composite beams. Parametric studies were preformed to evaluate the influences of the cross-sectional area ratio of the post-pouring joint to the whole bridge deck, as well as the difference of concrete age between the precast slabs and the post-pouring joint, on the long-term performance of the composite beam. The results indicate that the traditional method without considering the age difference would seriously underestimate the effect of creep and shrinkage of concrete bridge decks. The concrete age difference between the precast slabs and the post-pouring joint should be demonstrated for the life cycle design and long-term performance analysis of precast-assembled steel-concrete composite beams.

Step-by-step identification of industrial robot dynamics model parameters and force-free control for robot teaching

Binrui Wang,Junwei Fang,Shunan Qi,Ling Wang,Xiaolong Liu,Haijun Ren 대한기계학회 2023 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.37 No.7

In order to solve the problem of lack of flexibility in direct teaching of industrial robots under complex working conditions, dynamic inertia term compensation is combined with the traditional force-free control algorithm to reduce the traction in the teaching process in this paper. Firstly, considering the multi-dimensional, strongly nonlinear and multi-parameter characteristics of the 6-DOF manipulator dynamic model, a step-by-step parameters identification method based on genetic algorithm is proposed. This method can effectively reduce the computational complexity and improve the optimization speed of industrial robot dynamic model identification. Secondly, based on the internal torque analysis of industrial robot joints, a forcefree compensation control algorithm based on the torque control is designed. Finally, the effectiveness of the step-by-step robot dynamic model parameter identification method is verified by a traction teaching experiment. In the verification experiment, the relative error rate between the predicted torque and the actual torque calculated from the identification results is 1.64 % to 5.99 %. After increasing the inertia term compensation, the traction force of the teaching process is reduced by 28.6 %. The experimental results show that the identification result is more accurate, and the proposed force-free control algorithm significantly improves the compliance of the teaching process.

An Adaptive Complementary Sliding-mode Control Strategy of Single-phase Voltage Source Inverters

Hou, Bo,Liu, Junwei,Dong, Fengbin,Mu, Anle The Korean Institute of Electrical Engineers 2018 Journal of Electrical Engineering & Technology Vol.13 No.1

In order to achieve the high quality output voltage of single-phase voltage source inverters, in this paper an Adaptive Complementary Sliding Mode Control (ACSMC) is proposed. Firstly, the dynamics model of the single-phase inverter with lumped uncertainty including parameter variations and external disturbances is derived. Then, the conventional Sliding Mode Control (SMC) and Complementary Sliding Mode Control (CSMC) are introduced separately. However, when system parameters vary or external disturbance occurs, the controlling performance such as tracking error, response speed et al. always could not satisfy the requirements based on the SMC and CSMC methods. Consequently, an ACSMC is developed. The ACSMC is composed of a CSMC term, a compensating control term and a filter parameters estimator. The compensating control term is applied to compensate for the system uncertainties, the filter parameters estimator is used for on-line LC parameter estimation by the proposed adaptive law. The adaptive law is derived using the Lyapunov theorem to guarantee the closed-loop stability. In order to decrease the control system cost, an inductor current estimator is developed. Finally, the effectiveness of the proposed controller is validated through Matlab/Simulink and experiments on a prototype single-phase inverter test bed with a TMS320LF28335 DSP. The simulation and experimental results show that compared to the conventional SMC and CSMC, the proposed ACSMC control strategy achieves more excellent performance such as fast transient response, small steady-state error, and low total harmonic distortion no matter under load step change, nonlinear load with inductor parameter variation or external disturbance.

An Adaptive Complementary Sliding-mode Control Strategy of Single-phase Voltage Source Inverters

Bo Hou,Junwei Liu,Fengbin Dong,Anle Mu 대한전기학회 2018 Journal of Electrical Engineering & Technology Vol.13 No.1

In order to achieve the high quality output voltage of single-phase voltage source inverters, in this paper an Adaptive Complementary Sliding Mode Control (ACSMC) is proposed. Firstly, the dynamics model of the single-phase inverter with lumped uncertainty including parameter variations and external disturbances is derived. Then, the conventional Sliding Mode Control (SMC) and Complementary Sliding Mode Control (CSMC) are introduced separately. However, when system parameters vary or external disturbance occurs, the controlling performance such as tracking error, response speed et al. always could not satisfy the requirements based on the SMC and CSMC methods. Consequently, an ACSMC is developed. The ACSMC is composed of a CSMC term, a compensating control term and a filter parameters estimator. The compensating control term is applied to compensate for the system uncertainties, the filter parameters estimator is used for on-line LC parameter estimation by the proposed adaptive law. The adaptive law is derived using the Lyapunov theorem to guarantee the closed-loop stability. In order to decrease the control system cost, an inductor current estimator is developed. Finally, the effectiveness of the proposed controller is validated through Matlab/Simulink and experiments on a prototype single-phase inverter test bed with a TMS320LF28335 DSP. The simulation and experimental results show that compared to the conventional SMC and CSMC, the proposed ACSMC control strategy achieves more excellent performance such as fast transient response, small steady-state error, and low total harmonic distortion no matter under load step change, nonlinear load with inductor parameter variation or external disturbance.

Research on Adaptive Sliding Mode Control of Simplified Supersonic Missile System with Three Kinds of Uncertain Parameters

Jinyong Yu,Junwei Lei,Di Liu,Zexue Li 보안공학연구지원센터 2016 International Journal of Hybrid Information Techno Vol.9 No.11

A new kind of adaptive sliding mode control method is proposed for simplified missile model of pitch channel with time varying and uncertain parameters. Sliding mode control is an effective method for coping with system uncertainties. Adaptive method is integrated with sliding mode method and a Lyapunov function is constructed to guarantee the whole system is stable. Through the theoretical analysis and numericala simulation, comparison between PID control and sliding mode control shows that the adaptive sliding mode control of the uncertain missile system has a better control effect. And with consideration of three kind of parameter uncertainties in simulation, sliding mode control has better robustness.