SOME RELATIONS ON PARAMETRIC LINEAR EULER SUMS

Weiguo Lu,Ce Xu,Jianing Zhou Korean Mathematical Society 2023 대한수학회보 Vol.60 No.4

Recently, Alzer and Choi [2] introduced and studied a set of the four linear Euler sums with parameters. These sums are parametric extensions of Flajolet and Salvy's four kinds of linear Euler sums [9]. In this paper, by using the method of residue computations, we will establish two explicit combined formulas involving two parametric linear Euler sums S⁺⁺_p,q (a, b) and S^+-_p,q (a, b) defined by Alzer and Choi, which can be expressed in terms of a linear combinations of products of trigonometric functions, digamma functions and Hurwitz zeta functions.

Research on 3D Human Motion Capture Algorithm for Online Physical Education Teaching

Weiguo Li,Yongli Yang,Jing Zhou,Zhipeng Li 대한전자공학회 2023 IEIE Transactions on Smart Processing & Computing Vol.12 No.2

This study proposes to use the gradient descent method in data fusion to solve the problem of low learning efficiency of online sports courses by optimizing the attitude calculation and combining gait detection and zero speed correction to form a three-dimensional human motion capture system. The system was applied to online physical education teaching to improve teaching quality. The performance of the optimized attitude calculation algorithm and the Kalman filter algorithm was compared. The results show that the error angle of the data-fusion-attitude calculation algorithm was 1.67°, which is better than the Kalman filter algorithm. In the empirical analysis of the 3D human motion capture system designed by the research, the system could correctly capture the real human motion trajectory. Moreover, comparative analysis of the online physical education courses showed that the satisfaction of the online physical education courses embedded in the system was 90.62, which was much higher than other online physical education courses. These results show that the optimized attitude calculation algorithm can better capture real human movements, and the human motion capture system composed of this can improve the learning effect of online physical education courses. This method opens up new ideas for online physical education teaching.

An Optimized Multi-load Wireless Power Transfer System with Constant Load Currents

Zhe Zhou,Weiguo Li,Chenwen Cheng,Zhanfeng Deng,Fangyi Li,Qiuyu Shi,Chris Mi 전력전자학회 2019 ICPE(ISPE)논문집 Vol.2019 No.5

This paper proposes a multi-load wireless power transfer (WPT) system using repeater coils. The repeater unit that contains two repeater units is designed. The series-parallel-series (SPS) compensation method is used for each repeater unit. The constant load current for all the loads can be obtained with suitable resonant condition when neglecting the coils’ parasitic resistances. A feasible coil structure is designed where the two repeater coils in the same repeater unit are both bipolar that are placed perpendicularly so that the coupling between them can be neglected. A ferrite plate is inserted between the two bipolar coils in each repeater unit to enhance the magnetic coupling between adjacent units. Moreover, the proposed system has been optimized so that the system efficiency can be improved. The simulation results are given to validate the effectiveness of the proposed WPT system.

CeO2-La2O3/ZSM-5 sorbents for high-temperature H2S removal

Jiang Wu,Weiguo Zhou,Dongjing Liu 한국화학공학회 2016 Korean Journal of Chemical Engineering Vol.33 No.6

Performance of CeO2-La2O3/ZSM-5 sorbents for sulfur removal was examined at temperature ranging from 500 oC to 700 oC. The sulfur capacity of 5Ce5La/ZSM-5 was much bigger than that of CeO2/ZSM-5. H2 had a negative impact on the sulfidation; however, CO had little influence on sulfur removal. The characterization results showed that CeO2 and La2O3 were well dispersed on ZSM-5 because of the intimate admixing of La2O3 and CeO2, the major sulfidation products were Ce2O2S and La2O2S, the XRD and SEM results revealed that ZSM-5 structure could remain intact during preparation and sulfidation process, the H2-TPR showed that the reducibility of CeO2 can be remarkably enhanced by addition of La.

Research progress and the prospect of CO2 hydrogenation with dielectric barrier discharge plasma technology

Zhang Ziyi,Ding Honglei,Zhou Qi,Pan Weiguo,Qiu Kaina,Mu Xiaotian,Ma Junchi,Zhang Kai,Zhao Yuetong 한국탄소학회 2023 Carbon Letters Vol.33 No.4

In recent years, people are increasingly interested in CO2 hydrogenation to produce value-added chemicals and fuels (CH4, CH3OH, etc.). In the quest for an efficient treatment in CO2 methanation and methanolization, several technologies have been practiced, and DBD plasma technology gain attention due to its easily handling, mild operating conditions, strong activation ability, and high product selectivity. In addition, its reaction mechanism and the effect of packing materials and reaction parameters are still controversial. To address these problems efficiently, a summary of the reaction mechanism is presented. A discussion on plasma-catalyzed CO2 hydrogenation including packing materials, reaction parameters, and optimizing methods is addressed. In this review, the overall status and recent findings in DBD plasma-catalyzed CO2 hydrogenation are presented, and the possible directions of future development are discussed.

Influences of weaving architectures and impact locations on the ballistic resistance of UHMWPE fabric

Zihan Zhu,Hu Zhou,Xiangshao Kong,Fang Liu,Yongqiang Zhang,Cheng Zheng,Weiguo Wu 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.12

This study is devoted to reveal the influence of weaving architectures and impact locations on the ballistic resistance of UHMWPE (ultrahigh high molecular weight polyethylene) fabrics. Firstly, a mesoscopic model of UHMWPE fabric is established and the accuracy of the numerical method is verified. Subsequently, the models with different weaving architectures are further established, and the impact resistance performances are evaluated. Finally, the influence factors on the fabric ballistic resistance is explored. It is proved that the ballistic resistance of UHMWPE fabric mainly dominated by the tensile strength of yarn under highvelocity impact. The plain fabric shows best anti-ballistic performance, while basket and woven fabric are slightly inferior. The damage pattern of fabrics with different weaving architectures changes greatly. In addition, this study proposes a residual impact velocity correction model for projectile based on the probability distribution of impact positions, which can better characterize the protective ability of fiber fabrics.

High Step-Down Multiple-Output LED Driver with the Current Auto-Balance Characteristic

Quanming Luo,Binxin Zhu,Weiguo Lu,Luowei Zhou 전력전자학회 2012 JOURNAL OF POWER ELECTRONICS Vol.12 No.4

A high step-down multiple-output LED driver is proposed in this paper. Firstly, the derivation of the driver with dual-output is presented and its operation principle and steady state performance are analyzed in detail. Secondly, a high step-down N-channel LED driver is proposed and its current auto-balance characteristic and step-down ratio are analyzed. Finally, an experimental prototype is built and the experimental results are given. The theoretical analysis and experimental results show that the proposed driver has the following virtues: First, if load balancing is achieved, the voltage gain is 1/N that of a Buck driver, where N is the number of channels. Second, each output automatically has an equal output current, without requiring more current close-loop control circuits than a Buck driver. Last, the voltage stresses of the switches and diodes are lower than those of a Buck driver, meaning that lower voltage switches and diodes can be used, and a higher efficiency can be expected.

Direct Current Control Method Based On One Cycle Controller for Double-Frequency Buck Converters

Quanming Luo,Shubo Zhi,Weiguo Lu,Luowei Zhou 전력전자학회 2012 JOURNAL OF POWER ELECTRONICS Vol.12 No.3

In this paper, a direct current control method based on a one-cycle controller (DCOCC) for double frequency buck converters (DF buck) is proposed. This control method can make the average current through the high frequency and low frequency inductors of a DF buck converter equal. This is similar to the average current control method. However, the design of the loop compensator is much easier when compared with the average current control. Since the average current though the high frequency and low frequency inductors is equivalent, the current stress of the high frequency switches and the switch losses are minimized. Therefore, the efficiency of the DF buck converter is improved. Firstly, the operation principle of DCOCC is described, then the small signal models of a one cycle controller and a DF buck converter are presented based on the state space average method. Eventually, a system block diagram of the DCOCC controlled DF buck is established and the compensator is designed. Finally, simulation and experiment results are given to verify the correction of the theory analysis.

STUDIES ON SYNTHESIS OF METHYL GLYCOLATE AND METHYL METHOXY ACETATE FROM THE COUPLING OF FORMALDEHYDE AND METHYL FORMATE

He, Dehua,Huang, Weiguo,Liu, Jinyao,Zhou, Mingxing,Zhu, Qiming 한국화학공학회 1998 Korean Journal of Chemical Engineering Vol.15 No.5

Catalytic performance of various acids in the coupling reaction of formaldehyde and methyl formate to produce methyl glycolate and methyl methoxy acetate has been studied. The influence of reaction conditions, such as catalyst amount, reaction temperature, reaction time, and molar ratio of formaldehyde to methyl formate, has also been investigated. The results showed that the acid strength had great influence on the reaction, namely, stronger acds had higher activities. It was also found that the reaction temperature and time had significant effect on the reaction, and the preferable conditions were quite different as different acids were used.

Direct Current Control Method Based On One Cycle Controller for Double-Frequency Buck Converters

Luo, Quanming,Zhi, Shubo,Lu, Weiguo,Zhou, Luowei The Korean Institute of Power Electronics 2012 JOURNAL OF POWER ELECTRONICS Vol.12 No.3

In this paper, a direct current control method based on a one-cycle controller (DCOCC) for double frequency buck converters (DF buck) is proposed. This control method can make the average current through the high frequency and low frequency inductors of a DF buck converter equal. This is similar to the average current control method. However, the design of the loop compensator is much easier when compared with the average current control. Since the average current though the high frequency and low frequency inductors is equivalent, the current stress of the high frequency switches and the switch losses are minimized. Therefore, the efficiency of the DF buck converter is improved. Firstly, the operation principle of DCOCC is described, then the small signal models of a one cycle controller and a DF buck converter are presented based on the state space average method. Eventually, a system block diagram of the DCOCC controlled DF buck is established and the compensator is designed. Finally, simulation and experiment results are given to verify the correction of the theory analysis.