A New Species of the Spider Genus Oxyopes from Guangxi, China (Araneae: Oxyopidae)

Junxia Zhang, Yongqiang Zhang, 김주필(Joo-Pil Kim) 한국거미연구소 2005 한국거미 Vol.21 No.1

중국의 Guangxi 지역에서 채집된 Oxyopes 속의 1 신종인 Oxyopes gaofengensis sp. nov을 보고한다. A new species of the genus Oxyopes collected from Guangxi Province, China, is illustrated and described here under the name of Oxyopes gaofengensis sp. nov.

New Discovery of The Female Asemonea sichanensis(Araneae, Salticidae) from China

Junxia Zhang, Huiming Chen, 김주필(Joo Pil Kim) 한국거미연구소 2004 한국거미 Vol.20 No.1

깡충거미과의 중국산 미기록종인 Asemonea sichanensis Song & Chai, 1992을 보고하고자 한다. The present paper deals with the salticid species Asemonea sichanensis Song et Chai, 1992, of which the female is newly discovered and reported here.

Model Predictive Power Control of a PWM Rectifier for Electromagnetic Transmitters

Zhang, Jialin,Zhang, Yiming,Guo, Bing,Gao, Junxia The Korean Institute of Power Electronics 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.3

Model predictive direct power control (MPDPC) is a widely recognized high-performance control strategy for a three-phase grid-connected pulse width modulation (PWM) rectifier. Unlike those of conventional grid-connected PWM rectifiers, the active and reactive powers of permanent magnet synchronous generator (PMSG)-connected PWM rectifiers, which are used in electromagnetic transmitters, cannot be calculated as the product of voltage and current because the back electromotive force (EMF) of the generator cannot be measured directly. In this study, the predictive power model of the rectifier is obtained by analyzing the relationship among flux, back EMF, active/reactive power, converter voltage, and stator current of the generator. The concept of duty cycle control in the proposed MPDPC is introduced by allocating a fraction of the control period for a nonzero vector and rest time for a zero vector. When nonzero vectors and their duration in the predefined cost function are simultaneously evaluated, the global power ripple minimization is obtained. Simulation and experimental results prove that the proposed MPDPC strategy with duty cycle control for the PMSG-connected PWM rectifier can achieve better control performance than the conventional MPDPC-SVM with grid-connected PWM rectifier.

Model Predictive Power Control of a PWM Rectifier for Electromagnetic Transmitters

Jialin Zhang,Yiming Zhang,Bing Guo,Junxia Gao 전력전자학회 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.3

Model predictive direct power control (MPDPC) is a widely recognized high-performance control strategy for a three-phase grid-connected pulse width modulation (PWM) rectifier. Unlike those of conventional grid-connected PWM rectifiers, the active and reactive powers of permanent magnet synchronous generator (PMSG)-connected PWM rectifiers, which are used in electromagnetic transmitters, cannot be calculated as the product of voltage and current because the back electromotive force (EMF) of the generator cannot be measured directly. In this study, the predictive power model of the rectifier is obtained by analyzing the relationship among flux, back EMF, active/reactive power, converter voltage, and stator current of the generator. The concept of duty cycle control in the proposed MPDPC is introduced by allocating a fraction of the control period for a nonzero vector and rest time for a zero vector. When nonzero vectors and their duration in the predefined cost function are simultaneously evaluated, the global power ripple minimization is obtained. Simulation and experimental results prove that the proposed MPDPC strategy with duty cycle control for the PMSG-connected PWM rectifier can achieve better control performance than the conventional MPDPC-SVM with grid-connected PWM rectifier.

Review of Research on Yoga Intervention and Health Promotion Based on Citespace - A Comparative Analysis between China and the United States

Chengfei Zhang,Junxia Zhang,Jianjiao Su,Shengjie Liu,Lu Zhang 아시아건강운동학회 2019 Journal of Asian Society for Health & Exercise Vol.1 No.2

In order to research and inquire the development of yoga intervention and health promotion deeply in China and to find out the differences between China and the United States. This research uses Citespace software to analyze the evolution vein, research hotspots, and module knowledge groups of yoga intervention and health promotion research in China and the United States from three aspects: basic information, keywords, and co-citation networks. On this basis, the research theme, formation and development trend of each module knowledge group is analyzed, and the comparative analysis of the research concept, research content and research trend of each module group is carried out. The results suggest that the United States is significantly better than China in terms of total number of publications, trends in publications, volume of journals, and authors" related publications. Plenty of differences do exist in research models, research hotspots, and research continuity between China and the United States. The comparison shows that the United States focuses on the medical value of yoga, while China focuses on the value of yoga exercise. The differences in research concepts between China and the United States have led to differences in research approach and development trends between China and the United States. This study has played a positive role in clarifying the development status of yoga intervention and health promotion in China which could accelerate future research.

Rigid-flexible hybrid modeling and dynamic simulation of three-coordinate heavy-load transfer vehicle

Junxia Jiang,Haipeng Liao,Yuxiao He,Xinyuan Zhang 대한기계학회 2022 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.36 No.1

The spent fuel in the nuclear radiation environment is generally transported by transfer vehicles, which are required to be able to run smoothly under high speed and high acceleration. In this paper, dynamic analysis and simulation of a new type of heavy-load transfer vehicle were carried out. Firstly, the design structure of the transfer vehicle was presented, and the theoretical calculation methods for the forces on the V-shaped rollers and the dynamic deflection of the column were proposed. Then the working space of the vehicle was analyzed. And the dynamic model of rigid bodies and flexible bodies were established according to the Lagrange equations. Moreover, the velocity and acceleration of main components and the contact forces of the V-shaped rollers were analyzed by using ADAMS, and the optimal control strategy was proposed. Finally, the motors output torque of the vehicle was tested to validate the accuracy of the theoretical analysis and simulation. The experimental results are in good agreement with the theoretical and simulation results, and the dynamic performance of the transfer vehicle meets the design requirements.

Design and Implementation of Portable NMR Probe Magnet

Gao Junxia,Zhang Yiming,Tian Jiashen 한국자기학회 2017 Journal of Magnetics Vol.22 No.1

The NMR’s probe consists of the static magnetic field generator (magnetic source) and the RF coil. It is very strict for the homogeneity of the static magnetic field intensity of the magnetic source, so the cost of the magnetic source is more expensive in the entire nuclear magnetic resonance instrument. The magnetic source generally consists of electromagnet, permanent magnet and superconducting magnet. The permanent magnet basically needs not to spend on operation and maintenance and its cost of manufacture is much cheaper than the superconducting magnet. Therefore, the permanent magnet may be the only choice for the static magnetic field device if we want to use the magnetic resonance instrument as an analyzer for production by reducing price. A new probe magnet was developed on the basis of the permanent magnet ring in this paper to provide a technological way for reducing the manufacturing cost, weight and volume of the existing nuclear magnetic resonance instrument (including MRI) probe.

Design of a Novel Integrated L-C-T for PSFB ZVS Converters

Jiashen Tian,Junxia Gao,Yiming Zhang 전력전자학회 2017 JOURNAL OF POWER ELECTRONICS Vol.17 No.4

To enhance the zero-voltage switching (ZVS) range and power density of the phase-shift full-bridge (PSFB) ZVS converters used in geophysical exploration, an additional resonant inductor is used as a leakage inductance and a blocking capacitor which is equivalent to interlayer capacitance is integrated into a novel integrated inductor-capacitor-transformer (L-C-T). The leakage inductance and equivalent interlayer capacitance of the novel integrated L-C-T are difficult to determine by conventional methods. To address this issue, this paper presents accurate and efficient methods to compute the leakage inductance and equivalent interlayer capacitance. Moreover, the accuracy of this methodology, which is based on electromagnetic energy and Lebedev’s method, is verified by an experimental analysis and a finite element analysis (FEA). Taking the problems of the novel integrated L-C-T into consideration, the losses of the integrated L-C-T are analyzed and the temperature rise of the integrated L-C-T is determined by FEA. Finally, a PSFB ZVS converter prototype with the novel integrated L-C-T is designed and tested.

A New Species of the Genus Psechrus from China(Araneae: Psechridae)

Chen Huiming,Zhang Junxia,Song Daxiang,Joo-Pil Kim 한국거미연구소 2002 한국거미 Vol.18 No.1

Hybrid Control Strategy of Phase-Shifted Full-Bridge LLC Converter Based on Digital Direct Phase-Shift Control

Guo, Bing,Zhang, Yiming,Zhang, Jialin,Gao, Junxia The Korean Institute of Power Electronics 2018 JOURNAL OF POWER ELECTRONICS Vol.18 No.3

A digital direct phase-shift control (DDPSC) method based on the phase-shifted full-bridge LLC (PSFB-LLC) converter is presented. This work combines DDPSC with the conventional linear control to obtain a hybrid control strategy that has the advantages of linear control and DDPSC control. The strategy is easy to realize and has good dynamic responses. The PSFB-LLC circuit structure is simple and works in the fixed frequency mode, which is beneficial to magnetic component design; it can realize the ZVS of the switch and the ZCS of the rectifier diode in a wide load range. In this work, the PSFB-LLC converter resonator is analyzed in detail, and the concrete realization scheme of the hybrid control strategy is provided by analyzing the state-plane trajectory and the time-domain model. Finally, a 3 kW prototype is developed, and the feasibility and effectiveness of the DDPSC controller and the hybrid strategy are verified by experimental results.