• Journal of Power Electronics
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• v.14 no.2
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• pp.257-264
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• 2014

A novel converter-free AC LED driver that is highly resistant to the fluctuation of AC voltage is proposed in this study. By removing large passive components, such as the bulky capacitor and the large-value inductor, the integration of the driver circuit is enhanced while the driving current remains stable. The proposed circuit provides LED lamps with a driving current that can follow the sinusoid waveform to obtain a very high power factor (PF) and low total harmonic distortion (THD). The LED input current produced by this driving current is insensitive to fluctuations in the AC voltage. Users will thus not feel that LED lamps are flashing during the fluctuation. Experiment results indicate that the proposed system can obtain PF of 0.999 and THD as low as 3.3% for a five-string 6 W LED load under 220 V at 50 Hz.

• Fisheries and Aquatic Sciences
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• v.3 no.1
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• pp.14-22
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• 2000

The relationship between the distribution of demersal fishes and that of the water masses was examined by using the catches data and hydrographic data in the Yellow Sea and the East China Sea on May 13-19, 1996 and May 10-17, 1997. During the study period, the dominant fish species were Cleisthenes pinetorum herzinsteini, Lophiomus setigerus and Pseudosciaena polyactis. These three low temperature water species accounted for $21-24\%$ of the total catches. The percentage of the low temperature water species was high in the Yellow Sea and the coastal area on the continental shelf of the East China Sea but was low in the vincinity of Kyushu during the study period. In the East China Sea, the isotherm of $15^{\circ}C$ at 50m, mid layer depth, was located more southeast in 1996 than in 1997. The bottom water temperature was about it lower in 1996 than in 1997. The direction of the detided current on the continental shelf of the East China Sea was southward in 1996 and northward in 1997. Yellow Sea Bottom Cold Water (YSBCW) strongly expanded to south in 1996 when the northward current was weak. But, Tsushima Warm Current (TSWC) strongly intruded into the continental shelf of the East China Sea in 1997. As YSBCW expanded strongly to south in 1996, the percentage of the low temperature water species relative to the total catches was high. But, TSWC strongly intruded and the percentage of low temperature water fishes was low in 1997.

• Asian-Australasian Journal of Animal Sciences
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• v.31 no.7
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• pp.984-991
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• 2018

The beef industry is an important part of livestock and meat production in China. China ranks third in the world for beef production. With the rapid development of the Chinese economy, beef consumption has grown rapidly, and beef consumption has been increasing with rising per capita gross domestic production. However, the domestic beef industry in China has not been able to keep pace with growth in consumption, making China a net importer of beef from other countries. Moreover, the volume of production has increased little despite rising demand. The slowing of growth in beef production in recent years has led to a sharp rise in beef prices. Domestic beef production and consumption is restricted by a shortage of beef cattle inventory. The Chinese beef industry is facing many technical problems including transformation of traditional practices, feeding and management systems, and genetic improvement of cattle breeds. The long-term, sustainable development of the Chinese beef industry is an important issue for China.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.63
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• pp.209-244
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• 2014

This research had a close look into the expected results for both Korea and China from the contextual background of their efforts on FTA. In reality, we have to admit that Korea-China FTA has gains and losses for both countries in different fields and industries. Therefore, we suggest that people should not be myopic on the FTA matters, but take long-term perspectives in order to increase the entire benefits for companies and the country. Both countries should be able to build up strategic, reciprocal cooperation. We emphasize that the current FTA negotiations with China can turn out threats, not opportunities, if we do not establish effective negotiation strategies. Furthermore, we argue that, if we know and understand Chinese negotiation culture in advance, we could react to their strategic actions still more effectively. All in all, we could say that the purpose of our research is, first of all, to investigate the antecedents and consequences of the current Korea-China FTA negotiations; second, to divulge the Chinese negotiation culture, to presume possible negotiation strategies on the part of the Chinese, and to envision possible strategic reactions on our part; third, to delineate value creations from the successful Korea-China FTA in the future.

• Journal of Society of Preventive Korean Medicine
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• v.17 no.1
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• pp.137-147
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• 2013

Objectives : This study aims to report current trend of Mibyeong health policy and service in China from interview of China Technology Research Group. Methods : China Technology Research Group visited Guanganmen hospital, Yanhuang Dongfang Company, Xinjingzhen health center, and Shanghai Shuguang hospital. With an interpreter, We had interviews about Mibyeong health service and policy trend, medical instrument, and research issue. Results :Mibyeong health service was performed based on KY3H system and collaboration with traditional Chinese medicine hospital. Mibyeong health service consists of diagnosis with nine constitutional type, health guide and preventive treatment. Community health center also provide Mibyeong health service, with cooperative treatment of traditional Chinese medicine and western medicine. China's Mibyeong health policy is established by Top-down decision, even though there is not enough evidence for providing health service to consumer. Through constitutional diagnosis, examinations, and treatment, huge data have been stacked; however, assessment and research based on these data are not processed well. Cooperative treatment of traditional Chinese medicine and western medicine is widely provided to patients, and their works are relatively well classified. Conclusions : China plays leading role in Mibyeong service and it seems to be developed more than Korea's. Further study is necessary to establish Mibyeong policy and health service in Korea.

• Journal of Power Electronics
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• v.19 no.6
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• pp.1554-1565
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• 2019

When grid voltage is unbalanced, the grid-connected output current and power of Virtual Synchronous Generators (VSGs) are distorted and quadratic. In order to improve the power quality of a grid connected to a VSG when the grid voltage is unbalanced, a comprehensive coordinated control strategy is proposed. The strategy uses the positive sequence current reference command obtained by a VSG in the balanced current control mode to establish a unified negative sequence current reference command analytical expression for the three objectives of current balance, active power constant and reactive power constant. In addition, based on the relative value of each target's volatility, a comprehensive wave function expression is established. By deriving the comprehensive wave function, the corresponding negative sequence current reference value is obtained. Therefore, the VSG can achieve the minimum comprehensive fluctuation under the premise that the three targets meet the requirements of grid connection, and the output power quality is improved. The effectiveness of the proposed control strategy is verified by simulation and experimental results.

• THE INTERNATIONAL COMMERCE & LAW REVIEW
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• v.22
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• pp.255-285
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• 2004

After more than 15 years of negotiations, China was finally able to achieve the WTO membership, opening up new trade opportunities for China as well as existing WTO members. China accepted a special safeguard mechanism as one of its WTO- plus commitments. And in response, Korea has since introduced China special safeguard rules, which in simple terms, allows an invocation of safeguard measures against Chinese product imports under more lapse conditions than would normally be allowed under the existing general safeguard rules. China also introduced new safeguard rules in November 2001 in an effort to increase transparency in its operation of safeguard measures. However, the current article contends that the new rules pose a serious threat to free trade in the form of the retaliation provision, which enables China to take unilateral retaliatory actions against safeguard measures on Chinese product imports, It indicates that the provision could be operated in an arbitrary manner as the US Super 301, and lead to infringements of WTO disciplines. This paper indicates that the foregoing elements could lead to mort trade disputes between Korea China regarding safeguard measures and subsequent retaliations on the hills of the so called the Garlic War. The current article goes on to offer policy recommendations toward deterring such disputes. First, it recommends a more active invocation of Korea's own retaliatory provision against China's unilateral actions at least to gain negotiating leverage. Second, it sites problems involving China's still conspicuous state-trading practices, and proposes to raise issues again China to induce more faithful implementation of WTO disciplines Final, it stresses the importance of preventing disputes before they arise, and suggests several specific preventive measures.

• Journal of Electrical Engineering and Technology
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• v.13 no.6
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• pp.2402-2411
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• 2018

Fluoronitriles-$CO_2$ gas mixtures are promising alternatives to $SF_6$ in environmentally-friendly gas-insulated transmission lines (GILs). Insulating gas heat transfer characteristics are of major significance for the current-carrying capacity design and operational state monitoring of GILs. In this paper, a three-dimensional calculation model was established for a GIL using the thermal-fluid coupled finite element method. The calculated results showed close agreement with experimentally measured data. The temperature distribution of a GIL filled with the Fluoronitriles-$CO_2$ mixture was obtained and compared with those of GILs filled with $CO_2$ and $SF_6$. Furthermore, the effects of the mixture ratio of the component gases and the gas pressure on the temperature rise and current-carrying capacity of the GIL were analyzed. Results indicated that the heat transfer performance of the Fluoronitriles-$CO_2$ gas mixture was better than that of $CO_2$ but worse than that of $SF_6$. When compared with $SF_6$, use of the Fluoronitriles-$CO_2$ gas mixture caused a reduction in the GIL's current-carrying capacity. In addition, increasing the Fluoronitriles gas component ratio or increasing the pressure of the insulating gas mixture could improve the heat dissipation and current-carrying capacity of the GIL. These research results can be used to design environmentally-friendly GILs containing Fluoronitriles-$CO_2$ gas mixtures.

• Journal of Power Electronics
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• v.18 no.2
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• pp.511-521
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• 2018

Proportional capacitor current feedback active damping (CCFAD) has a limited valid damping region in the discrete time domain as (0, $f_s/6$. However, the resonance frequency ($f_r$) of an LCL-type filter is usually designed to be less than half the sampling frequency ($f_s$) with the symmetry regular sampling method. Therefore, ($f_s/6$, $f_s/2$) becomes an invalid damping region. This paper proposes an improved CCFAD method to extend the valid damping region from (0, $f_s/6$ to (0, $f_s/2$), which covers all of the possible resonance frequencies in the design procedure. The full-valid damping region is obtained and the stability margin of the system is analyzed in the discrete time domain with the Nyquist criterion. Results show that the system can operate stably with the proposed CCFAD method when the resonance frequency is in the region (0, $f_s/2$). The performances at the steady and dynamic state are enhanced by the selected feedback coefficient H and controller gain $K_p$. Finally, the feasibility and effectiveness of the proposed CCFAD method are verified by simulation and experimental results.

• Membrane and Water Treatment
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• v.8 no.4
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• pp.381-393
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• 2017

The inorganic components in tobacco sheet extract have significant influence on the sensory taste of the cigars and the harmful component delivery in cigarette smoke. To identify the contributions of the divalent inorganic components on harmful components delivery in cigarette smoke, a self-made selective electrodialysis was assembled with monovalent ion-selective ion exchange membranes. The influences of current density and extract content on the desalination performance were investigated. Result indicates that the majorities chloride, nitrate, and sulfate ions were removed, comparing with 50-60% of potassium and only less than 10% of magnesium and calcium ions removed in the investigated current density. The permselectivity of the tested cations across the Selemion CSO cation exchange membranes follows the order: $K^+>Ca^{2+}>Mg^{2+}$. A current density of $15mA/cm^2$ is an optional choice by considering both the energy consumption and separation efficiency. When the extract contents are in the range of 7%-20%, the removal ratios the potassium ions are kept around 60%, while the removal ratios of the calcium and magnesium ions fluctuate in the range of 16-27% and 8-14%, respectively. The tobacco smoke experiments indicated that the divalent metal ions have dual roles for the harmful component delivery in cigarette smoke. The divalent potassium and calcium ions were unfavorable for the total particulate matter emission but beneficial to decrease the HCN delivery in the mainstream cigarette smoke. The selective electrodialysis is a robust technology to decrease the harmful component delivery in cigarette smoke.