• Proceedings of the KIPE Conference
• /
• 2015.07a
• /
• pp.101-102
• /
• 2015

This paper is about the suggestion for the development in the commercialization for 3.6kW Class On-Board charger. It is suggesting non-insulation AC-DC Boost Power Factor correction circuit and insulation DC-DC resonant Converter for circuit design. In addition, Input AC voltage in the power supply is DCM control which can be designed to decrease the inductance for the inductor size to be reduced. DCM controls and Interleaved PFC can be designed to decrease the inductor size increasing the power conversions. Also, using the insulation DC-DC resonant converter, the efficiency can be increased. This system is verified using prototype hardware.

• Journal of Korea Technical Association of The Pulp and Paper Industry
• /
• v.42 no.5
• /
• pp.1-14
• /
• 2010

Bio-ethanol is a promising alternative energy source for reducing both consumption of crude oil and environmental pollution from renewable resources like lignocellulosic biomass such as wood, forest residuals, agricultural leftovers and urban wastes. Based on current technologies, the cost of ethanol production from lignocellulosic materials is relatively high, and the main challenges are the low yield and high cost of the hydrolysis process. Development of more efficient pretreatment technology (physical, chemical, physico-chemical, and biological pretreatment), integration of several microbiological conversions into fewer reactors, and increasing ethanol production capacity may decrease specific investment for ethanol producing plants. The purpose of pretreatment of lignocellulosic material is to improve the accessible surface area of cellulose for hydrolytic enzymes and enhance the conversion of cellulose to glucose and finally high yield ethanol production which is economic and environmental friendly.

• Journal of the Mineralogical Society of Korea
• /
• v.3 no.2
• /
• pp.65-71
• /
• 1990

Compositions and thermal changes of pyrrhotites from Ohtani and Uljin mines were examined by Arnold's method and DTA analysis. The results are as follow: 1) The compositions of hexagonal type pyrrhotite are in some range from 47.23-47.42 atom.% Fe in the Ohtani mine, and 47.40-47.64 atom.% Fe in the Uljin mine. 2) The compositions of hexagonal pyrrhotite with exsoluted lamellae of monoclinic pyrrhotite are in 47.35-47.50 atom.% Fe in the Ohtani mine, and 47.15-47.40 atom.% Fe in the Uljin mine. This fact does not agree with phase diagrams of Fe-S system shown by Nakazawa and Morimoto(1970) and Sugaki and Shima(1977). 3) DTA data show two endothermic peak corresponding to ${\gamma}$ and $\beta$ transformation. Sturctural conversions from order(intermediate) to disorder(high) forms occur at about $300^{\circ}C$ for hexagonal type and further lower temperature with increasing Fe-content.

• Proceedings of the Korean Information Science Society Conference
• /
• 2001.10a
• /
• pp.448-450
• /
• 2001

기존 종이책의 디지털 형태인 전자책은 종이책에 비해 인쇄와 유통, 저장 관리가 효율적이고, 멀티미디어 정보. 표현 등이 가능한 장점을 지니고 있기 때문에 향후 시장이 급성장할 것으로 예측되고 있다. 이와 같이 급성장한 전자책 시장을 위해 미국, 일본 등 세계 각국에서는 전자책 문서 표준을 제정하여 시장을 선점하고자 노력하고 있으며, 국내에서도 한국전자책컨소시엄(EBK)에서 지난 5월 전자책 문서표준으로 EBKS를 발표하였다. 이와 같이 전자책에 관한 여러 표준들이 존재함에 따라 각 표준을 따르는 전자책 들에 대한 상호호환의 문제가 발생하게 된다. 이러한 문제를 해결하기 위해서 본 논문에서는 EBKS를 중심으로 다른 전자책 문서표준 간의 변환기법에 대해 연구하였다. 이 변환기법은 향후 전자책 교환을 위한 필수적인 기술이 될 것이다.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2012.05a
• /
• pp.216-217
• /
• 2012

QM/MM 혼성 이론 방법인 ONIOM 계산을 통해, $CO_2$가 $B_N$-BNNT 벽면에서의 흡착 반응과 $H_2CO_3$로의 전환 반응 메커니즘을 규명함으로써 $B_N$-BNNT가 효과적인 $CO_2$ 흡착제와 $H_2CO_3$ 생성 반응 촉매로 개발 가능함을 확인하였다.

• Bulletin of the Korean Chemical Society
• /
• v.18 no.4
• /
• pp.433-438
• /
• 1997

(p-Methylbenzyl)-o-cyanopyridinium hexafluoroantimonate, a new catalyst, was synthesized by the reaction of o-cyanopyridine with α-bromo-p-xylene followed by exchange of counteranion with SbF6θ. We examined the effect of the catalyst on the bulk polymerization of tetrahydrofuran under various conditions. The catalytic activity was best in the presence of 1 : 1 of epichlorohydrin used as cocatalyst versus catalyst concentration. The resulting polymers had relatively low conversions in 1.0-40%. Their number average molecular weights were in the range of 800 to 5300. Propagation rate increased with increase in temperature according to an Arrhenius expression giving an activation energy of 62 KJ/mol. We also found catalyst proceeds via a cationic mechanism.

• Bulletin of the Korean Chemical Society
• /
• v.16 no.6
• /
• pp.507-511
• /
• 1995

Catalytic chlorination of chlorobenzene was studied in vapor phase using various solid-acid catalysts such as silica-alumina, alumina, zeolite and a modified clay prepared by impregnating bentonite with ferric chloride. The conversions of both chlorine gas and chlorobenzene showed high over silica-alumina, alumina and modified clay catalysts. However relatively large amounts of polychlorinated benzene derivatives were also observed. The active species of catalytic activity in chlorination of chlorobenzene in vapor phase were proved to be as Lewis acid sites by in-situ IR experiments. The strength of Lewis acid sites which were effective for the vapor-phase chlorination seemed to be having Hammett acidity Ho >-3.0. The selectivity to dichlorobenzenes was proved to be high over the zeolite catalyst due to their shape-selective properties. p-Dichlorobenzene or dichlorobenzene selectivities were improved more or less by changing the reaction conditions.

• Proceedings of the Korean Society of Propulsion Engineers Conference
• /
• 2012.05a
• /
• pp.414-415
• /
• 2012

Reforming catalyst of synthesis gas for GTL-FPSO process is presented in this paper. In the present study, the Ni foam catalyst was compared with the existing $Al_2O_3$ pellet catalyst. The SCR reaction on the catalyst was evaluated at the different temperature. The $CH_4$ conversions increased with the reactor temperature. Also, the Ni foam catalyst had a higher $CH_4$ conversion than a pellet catalyst.

• Nuclear Engineering and Technology
• /
• v.50 no.7
• /
• pp.1106-1111
• /
• 2018

Electromagnetic waves potentially have been used to heat overdense nuclear fusion plasmas through a double mode conversion from ordinary to slow extraordinary and finally to Electron Bernstein Wave (EBW) modes, OSXB. This scheme is efficient and has not any plasma density limit of electron cyclotron resonance heating due to cut-off layer. The efficiency of conversion depends on the isotropic launching angles of the microwaves with the plasma parameters. In this article, a two-step mode conversions of OSXB power transmission efficiency affected by the fast extraordinary (FX) loses at upper hybrid frequency are studied. In addition, the kinetic (hot) dispersion relation of a overdense plasma in a full wave analysis of a OSXB in Wendelstein 7X (W7-X) stellarator plasma has been numerically simulated. The influence of plasma dependent parameters such as finite Larmor radius, electron thermal velocity and electron cyclotron frequency are represented.

• International journal of advanced smart convergence
• /
• v.11 no.3
• /
• pp.79-84
• /
• 2022

Due to a series of online sex crimes cases and online class conversions caused by the spread of the coronavirus, alternatives to sex education in schools are urgently required. As a result of this study, the metaverse sex education platform was designed. Using this platform, learners are expected to cultivate correct adult awareness and digital citizenship. Within the metaverse platform, learners can participate more actively in learning. Instead of exposing one's name and face in a place dealing with sensitive gender issues, one can participate in education through his or her decorated avatar and participate in education much more actively than face-to-face education and express one's opinion through chat. In addition, education by level can be received regardless of time and place, which can have the effect of bridging the educational gap between urban and rural areas. In this paper, we propose a new sex education platform without time and space constraints by utilizing metaverse.