• Journal of the Korea Academia-Industrial cooperation Society
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• v.15 no.6
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• pp.3827-3831
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• 2014

This paper aims to solve the problem deterioration of power fuses. The deterioration of a power fuse is a cause of failure misoperation by a normal current flowing reduplicatively to fuse the element. An extension survey of a load feature rerating power fuse examined the power fuse deterioration removal, the cause of the deterioration of the power fuse, the front-after, and the thermal variation of the inside transformer room electric power equipment. The transformer showed an average improvement of $6[^{\circ}C]$. The temperature of the electrical line showed $7{\sim}8[^{\circ}C]$ improvement. The static condenser and direct reactor was $2{\sim}3[^{\circ}C]$ high-state maintenance the temperature and equipment syntonization relationship. In the subject of study $0.5{\sim}1.0[^{\circ}C]$ stabilizing three phase power fuse temperature differential was. Suggestion in the transformer room environment power equipment between the cause temperature happen elimination to deterioration of power fuse and temperature rise control.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2009.04b
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• pp.51-51
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• 2009

Thin Cross 초음파모터의 구조는 그림 1(a)와 같이 크로스형태의 얇은 스테이터에 윗면과 아랫면에 각각 8개의 압전세라믹이 부착된 형태이다. 압전세라믹의 분극방향은 로터와 접촉하는 스테이터의 중심부인 네 개의 타 점에서 순차적인 타원변위가 생성되도록 결정된다. 유한요소해석프로그램인 ATILA 5.2.4를 사용하여 최적설계된 모델을 제작하였고, 푸쉬풀 게이지, x-y 스테이지, rpm 메타, 토크 게이지를 이용하여 구동시스템을 구성하였다. 그림 1(b)는 마이크로컨트롤러(ATmega)를 이용한 구동 드라이버를 보여준다. 한 주기에서 1/4분주의 순차적인 네 개 의 구형파를 생성하고, 이를 push-pull회로를 통하여 90도의 위상차가 나는 정현파를 생성하여 초음파 모터의 구동 전원으로 사용한다. 피드백 회로인 맨코더와 AD 컨버터는 정속도 운전을 위해서 사용되었다. 제안된 구동드라이버를 이용하여 측정한 결과, 기존의 제품화된 드라이버와 비교하여도 특성의 큰 차이를 보이지 않았으며 피드백 회로를 통하여 부하변화에 따른 속도의 극심한 변화를 비교적 안정화 시킬 수 있었다. 입력전압을 증가시킬수록 속도는 선형적인 증가를 보였고 토크는 이와 반대로 감소하는 특성을 보였다. 피드백 제어회로가 없는 경우에는 프리로드 변화에 따른 극심한 속도 변화를 보였고, 피드백 제어를 하였을 경우에는 0.2~0.4[N]의 범위에서 정속도 운전이 가능함을 확인하였으며, 장시간의 운전에도 온도 및 속도특성이 안정적인 특성을 보였다.

• Journal of the Korean Institute of Intelligent Systems
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• v.23 no.2
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• pp.107-112
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• 2013

In the paper, velocity controller of switching module and temperature controller for the high-voltage static var compensator are proposed. Because of the continuous increase in demand for electric power, transmission and distribution facilities of power plant are required. There is a bottleneck problem of transportation routes according to new construction and expansion of power transmission facilities. Therefore there are researches to maximize the utilization of existing facilities and to increase transmission capacity without new construction. The previous static var compensator detects voltage of input circuit of power, switches the SCR directly and generates switching noise. The proposed method increases switching velocity and decreases noise using switching control based on the voltage between both sides of SCR. Also the proposed method enhance the stability using realtime temperature control for heating of the system from increase of switching velocity. We experiment the velocity and temperature control of the proposed high-voltage static var compensator in the real environment and verify the performance of the proposed system by applying in the real field.

• The Journal of the Convergence on Culture Technology
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• v.6 no.4
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• pp.591-598
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• 2020

Since COVID-19's 1st pandemic came in February 2020, the demand for telemedicine grew greatly that in most countries the deregulation for telemedicine policy have been implemented in more countries. Also in Korea, with the name of 'Non-face-to-face Treatment' telemedicine began to be approved. Telemedicine having strength in chronic disease management has been effective in more and more specialties along with the recent development of ICT that it is expected to contribute to the improvement of the quality of healthcare service and creation of new treatment model. On the contrary it may also exacerbate the distortion in the hospital healthcare service industry in Korea, which is the excessive tipping toward large hospitals. So the dual promotion policy approach in which the settlement of family doctors system extensively utilizing telemedicine for chronic disease management and the support for tertiary hospitals and hospitals focusing on treating foreign patients to provide quality service using telemedicine technology are pursued simultaneously are recommended.

• Journal of the Korean Chemical Society
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• v.24 no.2
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• pp.115-120
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• 1980

A kinetic study of the methanolysis of t-butylbromide and benzoylchloride in methanol-acetonitrile mixtures is reported. First order rate constants for the methanolysis of t-butyl bromide show maximum at $X_{MeOH}$=0.75∼0.9 and 25∼$50^{\circ}C$. Apparent second order rate constants for the methanolysis of benzoylchloride also show maximum at $X_{MeOH}$= 0.6∼0.95 and 12∼$26^{\circ}C$. The maximum rate is ascribed to the solvent structure change; the addition of acetonitrile to methanol perturbs the methanol structure increasing the free methanol molecules available to stabilize the transition state for the methanolysis of t-butylbromide and benzoylchloride. It has been shown that methanol acts as nucleophilic and electrophilic catalyst upon methanolysis of t-butylbromide and as electrophilic catalyst upon methanolysis of benzoylchloride.

• Journal of the Korea Institute of Information and Communication Engineering
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• v.23 no.2
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• pp.215-222
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• 2019

Advances in technologies about 3D (three-dimensional) printing and smart factory related issues will have the effect of reducing the cost of building a smart factory and making various types of service available. Manufacturers and service providers of small assets work with outside experts to provide small amounts of customized ordering services. If customers have to disclose their private information to subscribe to a new service, they may be reluctant to use it and the availability of developed technology may cause slow progress. We propose a new protocol for customized order service for smart factory. The proposed approach is designed to meet requirements of security and based on smart contract in IoT convergence network. We analyzed the requirements of the proposed approach which provided anonymity, privacy, fairness, and non-repudiation. We compared it with closely related studies to show originality and differences.

• Journal of Forest and Environmental Science
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• v.17 no.1
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• pp.29-36
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• 2001

Compared to other industries, pulp and paper industry use a lot of water. As a result, a large amount of the waste water is discharged in the pulp and paper industry. This study was investigated to prevent the environmental pollution terribly faced with our society nowadays. In the waste water of pulp and paper, there are so many things in the waste water, like fiber, filler, and other organic solvent etc. so we must remove them from our environment. This study was investigated to experiment on test of impressed filtration with the kind and quantity of coagulant and the variance of pressure. In this study, we used feds, alums. $CaCl_2$, polymer as a coagulant and these pressure was 49, 98, 147, 196kpa. According to this study, we measured the speed of filtration and turbidity, measuring filtrated water. According to the values, we know the fact that as the consistency of coagulant and pressure were high, the filtration was good.

• Korean Journal of Clinical Pharmacy
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• v.22 no.2
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• pp.167-175
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• 2012

Different studies have been conducted regarding caffeine as psychostimulant drugs and its effects as well as determination in various materials. Since, coffee and tea are most drinkable beverage in the world and their major constituent is caffeine. So, analysis of the effect of equal amount of caffeine in coffee and tea with respect to SD rats was studied. The present methodology was purposed to determine and validate caffeine amount in different brands of coffee and tea, and canvass locomotor and behavioral patterns of SD rats after administrating coffee and tea orally consisting of same amount of caffeine (10, 30 mg/kg). Determination of caffeine in different brands of coffee and tea and validation of caffeine were evaluated using HPLC. Depending upon different brands of tea and coffee, caffeine amount was altered. Meanwhile, amount of caffeine in tea was directly proportional to the temperature of liquid. Coffee and tea (Instant Maxim original coffee$^{(R)}$ and earl grey black tea$^{(R)}$) consisting 10, 30 mg/kg of caffeine were studied in SD rats for locomotor activity and behavioral patterns using Tru Scan 99. The locomotor activities of SD rats were increased after administration of coffee and tea consisting caffeine compared to water. The coffee consisted of higher amount of caffeine exhibited steep movement of SD rats. Similarly, rearing and scratching of SD rats as frequency and duration were increased in coffee and tea consisting caffeine compared with water. The study revealed that coffee and tea had effects in locomotor activity and behavioral patterns of SD rats.

• Journal of the Korean Vacuum Society
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• v.5 no.4
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• pp.284-291
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• 1996

We have implemented a fast pressure control system for the transport chamber of a high vacuum cluster tool for advance semiconductor fabrication and evaluated its performance. To overcome the typically slow response of mass flow controllers, the modified experimental method is used very effectively to optimize the pressure control procedure. We successfully obtained quite fast pressure control by adjusting the starting time and eht tuning constants by the Ziegler-Nichols method. In the transport pressure $10\times 10^{-5}$ torr, actual pressure control starts from 4 sec after an initial gas load of 2.1 sccm. As a result, optimum conditions for the tuning constants are the rise rate of 0.02 torr/sec, the lag time of 0.15 sec, and the sampling period of 0.5 sec. Then the settling time is about 9 sec within about $\pm$0.5% for the referenced value. This settling time is enhanced above 75 percents in comparison with conventional experimental method. To account for the experimental effects observed, a theoretical model was developed. This experimental result has a tendency to fit with the theoretical result of $\omega$=-1.0.

• Korean Journal of Plant Resources
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• v.14 no.1
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• pp.38-42
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• 2001

This study was conducted to stable direct sowing cultivation with seedling growth promotion by plant growth regulator treatment in onion seed(Allium cepa L.) The emergence percentage of soaked seed in BA, GA$_3$, and kinetin solution were higher than control seed, and those were 93.0, 94.3, 93.8%, respectively. The plant height was significant elongation in growth regulators treated seed, and those effects were high GA$_3$, kinetin and BA in the order, and the extend were high as increasing the growth regulator solution concentration in GA$_3$ and BA, and that was reverse in kinetin. The No. of leaf was increased in growth regulators treated seed, and the extend were similar among the growth regulators. The No. of root was increased significantly in growth regulators treated seed, and the extend were high in GA$_3$, BA and kinetin in the order.