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A Novel Ripple-Reduced DC-DC Converter
Yu Tao,Sung-Jun Park 전력전자학회 2009 JOURNAL OF POWER ELECTRONICS Vol.9 No.3
A DC/DC converter generally needs to work under high switching frequency when used as an adjustable power supply to reduce the size of magnetic elements such as inductors, transformers and capacitors, but with the rising of the switch frequency, the switch losses will increase and the efficiency will reduce. Recently, to solve these problems, research is actively being done on a soft switching method that can be applied under high frequency and on a PWM converter that can be applied under low frequency such as a multi-level topology. In this paper a novel DC-DC conversion method for reducing the ripple of output voltage is proposed. In the proposed converter, buck converters are connected in series to generate the output voltage. By using this method, the ripple of output voltage can be reduced compared to a conventional buck converter. Particularly when output voltage is low, the number of acting switching elements is less and the result of ripple reduction is more obvious. It is expected that the converter proposed in this paper could be very useful in the case of wide-range output voltage.
Design of Simple Controller for Minicar BLDC Motor Based on Low Cost Microprocessor
Yu Tao,Doo-Young Song,Zhang Lei,Sung-Jun Park,Tae-Uk Jung,Cheul-U Kim 전력전자학회 2007 전력전자학술대회 논문집 Vol.- No.-
If used to drive the minicar, the BLDC Motor has advantages of weightless, efficient, small-size and credibleness. In this paper at first the position detecting method for BLDC was introduced, secondly the simulation of control algorithm was done and at last the prototype controller based one chip processor MEGA48 was fabricated. The controller proposed has characteristic of cheap cost, reliable performance and totally meeting demands of minicarcontrol.
Effects of Influencing Factors on a Lab-Scale Device for Dynamic Scaling Mitigation
Tao Yu,Ying Wang,Jiayu Song,Baichun Wu,Xin Zhang,Chengtun Qu 한국전기전자재료학회 2021 Transactions on Electrical and Electronic Material Vol.22 No.6
To investigate the dynamic scaling properties of produced water from oil and gas fields, in this study, an experimental dynamic scaling mitigation device consisting of a filler cylinder, a sewage circulation device, and a heating device was designed. The effects of important factors, namely, initial concentration of scale-forming ions, contact time, temperature, and flow rate, on the dynamic scaling process were investigated using this device. The results obtained showed that the rate of scale adsorption on cotton fiber decreased gradually as the initial concentration of the scale-forming ions increased, and the scale adsorption rate peaked at 97.5% when the contact time was between 2 and 8 h. It was also observed that the maximum scale adsorption rate and amount corresponded to experimental temperatures of 50 and 40°C, respectively. Furthermore, the maximum scale adsorption rate was 94% at a flow rate of 60 L/h, while the scale adsorption amount peaked at a flow rate of 100 L/h. These results provide important guidelines for the establishment of a rapid measurement method for dynamic scaling in produced water from oil and gas fields and for the evaluation of water quality stability for water flooding extraction.
TAO-YU ZHOU,HUI WANG,XIAO-PING KANG,XIN-QUAN XIN 성균관대학교(자연과학캠퍼스) 성균나노과학기술원 2013 NANO Vol.8 No.4
A novel tree-like nano-cadmium sulfide (CdS) with the fractal feature is synthesized by solid-state reaction at room temperature from complex precursor with aminotrimethylenephosphonic acid (ATMP) as ligand. The obtained sample is the crystalline cubic beta cadmium sulfide. The tree is composed of nanorods with an average diameter of ca. 95 nm and a length of up to 100–650 nm. The nanorods grow in the asymmetrical "Y" shape. The amount of ATMP plays an important role in the formation of fractal structure. Nonlinear optical (NLO) measurements by the Z-scan technique exhibit that the tree-like fractal nano-CdS has the third-order nonlinear optical properties of both NLO absorption and NLO refraction with self-focusing effect and the optical limiting performance.
BLDC Motor Control System using ASK DC-link PLC Technology
Tao Yu,Sung-Geun Song,Se-Min Kim,Kwang-Heon Kim,Sung-Jun Park 한국조명·전기설비학회 2009 조명·전기설비학회논문지 Vol.23 No.3
Power line communication or power line canier (PLC) is a system for carrying data on a conductor and can also used for electric power transmission. Now the powers used in the motor drive system are mostly DC sources. Even AC powers in some systems are generated from DC sources by the inverter. It is can be forecasted that the DC-link PLC technology will be widely used in various industrial fields. In this paper a novel BLDC motor control system using ASK DC-link PLC technology is proposed. The characteristic of this system is that the communication only needs 2 DC lines and there are no additional lines to translate the reference signals. The number of signal cables can be minimized when the DC-link PLC method is applied in the multi motor control system and the slip ring design also be simplified when this method is applied in rotation machines. The proposed motor control system is clarified by the PSIM and MATLAB simulations and tested through the hardware prototype.
Tao Yu,Yanyan Yang,곽이성,송관규,김미연,이만휘,조재열 고려인삼학회 2017 Journal of Ginseng Research Vol.41 No.2
Background: Ginsenoside Rc (G-Rc) is one of the major protopanaxadiol-type saponins isolated from Panax ginseng, a well-known medicinal herb with many beneficial properties including anticancer, antiinflammatory, antiobesity, and antidiabetic effects. In this study, we investigated the effects of G-Rc on inflammatory responses in vitro and examined the mechanisms of these effects. Methods: The in vitro inflammation system used lipopolysaccharide-treated macrophages, tumor necrosis factor-a/interferon-g-treated synovial cells, and HEK293 cells transfected with various inducers of inflammation. Results: G-Rc significantly inhibited the expression of macrophage-derived cytokines, such as tumor necrosis factor-a and interleukin-1b. G-Rc also markedly suppressed the activation of TANK-binding kinase 1/IkB kinase ε/interferon regulatory factor-3 and p38/ATF-2 signaling in activated RAW264.7 macrophages, human synovial cells, and HEK293 cells. Conclusion: G-Rc exerts its anti-inflammatory actions by suppressing TANK-binding kinase 1/IkB kinase ε/interferon regulatory factor-3 and p38/ATF-2 signaling.
Kinetic and thermodynamic study of Eu(III) sorption on natural red earth in South China
Tao Yu,Wang-Suo Wu,Zhi-Rong Liu,Si-Wei Zhang,Zheng-Wei Nie 한국화학공학회 2013 Korean Journal of Chemical Engineering Vol.30 No.2
We did a kinetic and thermodynamic study of Eu(III) sorption on natural red earth (NRE) in South China as a function of contact time, pH values, ionic strength, humic acid (HA) and temperature under ambient conditions. Linear and nonlinear regression methods in selecting the optimum sorption isotherm were applied on the experimental data. The results suggest that sorption of Eu(III) on NRE can be described by a pseudo-second-order rate equation and strongly dependent on ionic strength at pH<7. Sorption of Eu(III) on NRE increased with increasing temperature,two-parameter and three-parameter isotherms were applied to analysis the equilibrium adsorption data, and a comparison of linear and nonlinear regression methods was done. The thermodynamic parameters (ΔH0, ΔS0 and ΔG0) of Eu(III)sorption on NRE at different temperatures were calculated from the temperature-dependent sorption isotherms, indicating that the sorption process of Eu(III) was spontaneous. The results showed that the nonlinear method is a better way to obtain the isotherm parameters and the data were in good agreement with the Freundlich isotherm model.