• 시멘트 심포지엄
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• 1호
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• pp.50-55
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• 1973

Improvement of grinding efficiency about open circuit grinding mill in cement production was investigated and the results were as follows; 1. Controlled the steel ball by charging ratio. 2. Raised the slot ratio from 3$\%$ to 4.5$\%$

• 대한전기학회논문지:전기기기및에너지변환시스템부문B
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• 제52권5호
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• pp.203-210
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• 2003

This paper describes high voltage and high energy density capacitor developed for pulsed power applications. The rated voltage of the developed capacitor is DC 22 [kV], the capacitance is 206 [$\mu$F] and the energy density is about 0.7 [kJ/kg]. Polypropylene film and kraft paper were used as the dielectrics. The ratio of the thickness of each dielectric material which consists of the composite dielectric structure, stacking factor and the termination method were determined by the charging and discharging tests on model capacitors. In terms of energy density, the developed capacitor has higher energy density compared with the products of foreign leading companies. In addition, it has been proved that the life expectancy can be more over 2000 shots through the charging and discharging test. The voltage reversal factor was 20%. This capacitor can be used as numerous discharge applications such as military, medical, industrial fields.

• 한국IT서비스학회지
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• 제19권3호
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• pp.89-100
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• 2020

The wireless power transmission market is growing at an average annual rate of 51.5% from $ 16.4 billion in 2015 to $ 131.1 billion in 2020. However, there are limitations to commercialization due to the development of standards and technologies. Thus, this study identified trends in standards and regulations by market and by country. The research collected and filtered a total of 69,488 worldwide wireless power transfer patents by June 2019 and extracted a total of 28,555 patents. Based on this, technology development status was analyzed and predicted. In this study, long-distance and short-range technology development with high technology development difficulty and low technology development ratio could lead to growth of the entire wireless charging market. It is analyzed that investment and policy preparation are necessary to secure source technology for long-distance / near technology development than China, Japan and Europe.

• 디지털콘텐츠학회 논문지
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• 제5권3호
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• pp.234-238
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• 2004

이동통신 시스템 설비는 크게 이동가입자의 접속을 위한 커버리지(Coverage)와 트래픽 증가시 소요되는 추가 트래픽 이용(Usage) 장비로 나눌 수 있으며, 이 분류에 따라 유선사업자가 이동사업자에게 지불하게 되는 접속료의 규모가 결정된다. 본 논문에서는 국내 유선사업자와 이동통신 사업자간의 접속료 산정을 위한 사전 작업으로서 투자요구에 따른 이동통신 시스템 설비를 분류하기 위한 새로운 기준을 제시한다. 새로이 제시하는 분류 기준에서는 시스템 설비의 용량(Erlang, throughput)과 가입자 수요를 이용하여 설비별로 커버리지의 비율을 적용함으로서 사업자간 양보를 통한 상호 합의점을 도출할 수 있다.

• 조명전기설비학회논문지
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• 제24권10호
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• pp.114-122
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• 2010

Today, effort to reduce greenhouse gas emissions is to be strengthened worldwide. And environment-friendly vehicle is being magnified because of energy saving and minimization of environmental pollution. In the future, the construction of EV charging facilities will be needed for Prevalence of EV in the Public Housing. So in this paper, we survey and analyze data of power usage and owned vehicles on the existing public housing according to season, day and time. And, we reviewed appropriate configuration ratio according to three kind of case. Besides, we calculate Prevalence Estimates of EV and utilization factor based on analysis result. And finally, we try to study for case model.

• Design & Manufacturing
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• 제12권3호
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• pp.55-59
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• 2018

In a multi-cavity mold having a runner layout of a fish bone structure, problems of unbalanced filling between cavities occur constantly. Unbalanced charging lowers the dimensional accuracy of a molded article and causes deformation after molding. To solve this problem, the gate size connected to each cavity is adjusted using the BGV (Balanced Gate Value) equation. In this paper, in order to solve the filling imbalance problem of the runner layout mold of fish bone structure through injection molding analysis study, we compared the charging imbalance phenomenon before and after improvement after adjusting the gate size by applying BGV equation. From the results of the molding analysis, the shrinkage ratio before and after the improvement of the molded article was improved by only about 0.08%. Based on these results, it was confirmed that the charging imbalance problem was not significantly improved even when the BGV equation was applied.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 춘계학술대회
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• pp.1499-1505
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• 2003

Rapid development of electronic technology requires small size, high density packaging and high power of electronic devices. So, in this paper, characteristics on oscillating heat pipe according to operating conditions(environment temperature, charging ratio of working fluid, inclination) based on experimental study was investigated. From the experimental results, $25^{\circ}C$environment temperature), R-141b(working fluid)40%(charging ratio) was best performace at others of inclination angle and The top heating mode of OCHP performed 80% efficiency of the bottom heating mode.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회B
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• pp.2369-2374
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• 2008

In the precision hot plate for wafer processing, the temperature uniformity of upper plate surface is one of the key factors affecting the quality of wafers. Precision hot plates require temperature variations less than ${\pm}1.5%$ during heating to $120^{\circ}C$. In this study, we have manufactured the flat plate heat pipe hot chuck of circle type(300mm) and investigated the operating characteristics of flat plate heat pipe hot chuck experimentally. Various liquids(aceton, FC-40, water) were used as the working fluid and charging ratio was changed($14{\sim}36\;vol.%$). Several cases were tested to improve temperature uniformity. Major working fluid to be investigated was water. Using water, various parameters such as charging ratio, wafer operation on-off time, different working fluids. In case of water, the temperature uniformity was ${\pm}1.5%$, response time of wafer were investigated.

• Journal of Advanced Marine Engineering and Technology
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• 제29권4호
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• pp.436-442
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• 2005

Rapid development of electronic technology requires small size, high density packaging and high power of electronic devices. In this paper, characteristics on oscillating heat pipe according to operating conditions (environment temperature, charging ratio of working fluid, inclination) based on experimental study was investigated From the experimental results $25^{\circ}C$(environment temperature) R-141b (working fluid) $40\%$ (charging ratio) was best performace at others of inclination angle and the top heating mode of OCHP performed $80\%$ efficiency of the bottom heating mode.

• International Journal of Air-Conditioning and Refrigeration
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• 제13권4호
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• pp.217-224
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• 2005

The purpose of this study was to develop a cooler/heater using a thermoelectric module combined with a parallel flow type pulsating heat pipe with R-142b as a working fluid. The experiment was performed for 16 thermoelectric modules (6A/15V, size: $40\times40\times4mm$), varying design parameters of the heat pipe (inclination angle, working fluid charging ratio, etc.). Experimental results indicate that the optimum charging ratio and the inclination angle of the parallel flow type pulsating heat pipe were $30\%$ by volume and $30^{\circ}$, respectively. The maximum cooler/heater capacity were 479 W (COP: 0.47) and 630 W (COP: 0.9), respectively.