전자장치 냉각을 위한 수직수로에서의 열-사이펀 비등실험

전진석,곽호영 중앙대학교 기술과학연구소 1989 기술과학연구소 논문집 Vol.19 No.-

As a result of continuing efforts to improve the circuit performance, the number of devices in the package such as VLSI and the speed of computation has been considerably increased. In fact, during the past two decades the heat flux at the chip level has increased by more than an order of magnitude. Therefore one of the problems faced by engineers who are designing computers, is how to cool the electronic hardware of the computer. The LSI or VLSI chips must be cooled in a manner that the maximum temperature of device junction dose not exceed 85℃ in order in order to keep the reliability. The method of "air cooling" is enough to cool the components such as tube or transistor because of their relatively low heat generation rate. But it is not enough to cool VLSI with such method. Recently "immersion cooling" is studied to solve that problem by many investigators because heat transfer is more effective than others. This paper describes an experimental study on boiling heat transfer between vertical isoflux plates with asymmetric heating with a dielectric fluid, FC-72. This study found that the channel width is not a significant parameter for immersion cooling with FC-72 and that the heat transfer from the vertical plates is more effective than the horizontal plates. And this study demonstrated the possibility of use of "immersion cooling" between narrow PCB's.

지형정보시스템을 이용한 임도노선의 선정에 관한 연구

全權石,麻鎬燮 경상대학교 농업생명과학연구원 2002 농업생명과학연구 Vol.36 No.2

임도망의 종합적인 계획을 위하여 지형정보시스템을 이용하여 경남 남해군에 위치한 금산주변의 국유림을 대상으로 몇가지 노선선정 기준에 따라 임도노선을 선정 하였다. 종단물매를 고려하여 임도망을 계획한 결과, 총연장 및 임도밀도는 20.41㎞, 6.92m/ha로 나타났으며, 일부구간의 노선이 대상지역의 경계영역과 인접하게 선정되어져 임업적 측면에서는 그 효율성이 떨어지는 경향이었다. 종단물매만을 고려한 임도망의경우 최소비용경로에 의한 격자별 누적비용은 10구역으로 구분되었으며, 이때 최고 누적비용은 종단물매만을 고려한 결과 22,548의 값을 가졌다. 비용에 의해 선정되어진 임도망을 1노선과 7노선은 시험림 3임반의 경계점에서 중복으로 노선이 선정되었으며, 중복선정된 2노선의 연장은 2.72㎞로 나타났다. 그리고 4노선과 5노선에서도 0.8㎞가 중복 선정되어 총 중복된 연장거리는 3.52㎞로서 다소 높게 나타났다. 구조적인 측면의 종단몰매와 생산적인 측면의 투자효과를 최대화하기 위하여 이들을 조합하여 노선을 계획한 결과 총연장 및 임도밀도는 21.15㎞, 7.17m/ha로서 구조적인 측면의 임도망 계획결과에 비하여 높게 나타났다. 종단물매와 임목축적을 고려한 임도망의 경우 최소 비용경로에 의한 격자별 누적비용은 9구역으로 구분되 이때 최고누적비용은 55.065의 값을 가졌다. 비용에 의해 선정되어진 임도망의 분석결과 3노선과 7노선은 3임반에서 일부구간이 중복선정되어 중복된 2노선의 연장은 0.95㎞이다. 그리고 4노선과 5노선에서도 구조적인 경우의 대안임도와 마찬가지로 0.8㎞가 중복 선정되어 총 중복된 연장거리는 1.73㎞로 나타났다. GIS 기법에 의한 임도망의 계획은 각 대안별 평가를 통하여 최종 의사결정자가 최적의 임도망을 선택할 수 있는 의사결정지원체계로서 중요한 정보를 제공할 수 있는 것으로 평가된다. The purpose of this study is to suggest the proper method for planning an optimal forest road network in mountains forest using geographic information system (GIS) in the National Forest of Mt. Kumsan at Namhae-gun, Gyungsangnam-do. In the forest road network planning by the minimum longitudinal gradient, The total length was 20.41 km, and road density was 6.94m/ha. Some of road alignment selected in out-line of study area. So, it appeared that forest road have a low effectiveness in yarding function. The division area of mesh by accumulative cost divide into 10 area. The maximum value by cost path was 22,548. The road length overlapped by cost path was more long than that of mixed with the minimum longitudinal gradient and the maximization of investment effect as 3.52 km. In the forest road network planning by mixed with the minimum longitudinal gradient and the maximization of investment effect, The total length was 21.15 km, and road density was higher than that of the minimum longitudinal gradient as 7.17m/ha. The some of forest road selected in out-line of study area. The division area of mesh by accumulative cost divide into 9 areas. The minimum vlue by cost path was 55,065. The road length overlapped by cost path was more short than that of the minimum longitudinal gradient as 1.73 km. So, it appeared that forest road has an high effectiveness in yarding function. Therefore, it was considered that the GIS could provide an effective and reasonable solutions for planning of optimal forest road network.

자은철광석으로부터 희토류광물 회수에 관한 연구

전호석,김준수,문영배,이재장 江原大學校 産業技術硏究所 2001 産業技術硏究 Vol.21 No.A

The separation of rare earths minerals is verb difficult because of their similar chemical properties. The rare earth minerals are used as the mixed rare earth minerals or the misch metal without separation to each element. However, the high purity rare earths are recently produced commercially to each element so they there are used as the materials for high tech. Based on the characterization results for the raw minerals, we have developed a combined process containing gravity seperation, magnetic severation and flotation. The result obtained from this study is monazite concentration of TREO grade 69.11% and Recovery 56.02%.

성균관대학교 멀티미디어 원격교육 시스템(배움 한마당) 개발에 관한 연구

김석수,권해문,이상권,김상진,전진호,황대준 成均館大學校 科學技術硏究所 1997 論文集 Vol.48 No.1

We propose SKKU Multimedia Distance Education System for distance education between nature science campus(Suwon) and social science campus(Seoul) in Sung Kyun Kwan University on DooRae (Distributed Object Oriented Multimedia Application Crafting Environment for Collaboration) framework (or platform). We support ONE : N study mode for a group lecture and discussion between two campus, and also we support mediation for floor mode of a group lecture and brain storming for floor mode of discussion. The communication portocol of this system is composed of TCP/IP and UDP, and the network type is composed of WAN(El line)for between the Suwon campus and Seoul campus, ATM LAN for each campus(local site). And, this system supports the application development of the collaborative multimedia environment connected with the various network in the CBM (Computer based Multimedia) based. Also, it does not restrict on space between a teacher(s) and a student(s) into cyberspace which made by network. This system has an interaction, late comer, a question and an answer, multi-session, application sharing and whiteboard which resembles chalkboard. Also, various supplementary functions such as video conference and voice conference for this system are what makes face-to-face education effective. Also it supports real or non-real type. The operation system developed on windows 95.

심첨부 비후 심근증에서 심근 내 미세 관상동맥의 혈류 예비력 평가 : 경흉부 도플러 심초음파를 이용한 연구 Study Using Transthoracic Doppler Echocardiography

윤호중,박철수,신재원,임상현,조은주,정해억,전희경,오용석,정욱성,김재형,최규보,홍순조 대한순환기학회 2004 Korean Circulation Journal Vol.34 No.3

하악골 골절 환자에 있어 수술후 합병증으로 발생한 골수염의 치험례

윤규호,전인성,신용길,박준호,허남오,방석준 大韓顎顔面成形再建外科學會 1996 Maxillofacial Plastic Reconstructive Surgery Vol.18 No.4

The term osteomyelitis literally means inflammation of bone marrow. It is described as an inflammatory condition of bone primarily engaging the medullary Following circulatory collapse and ischemia, the involved portions of the bone become necrotic. Cellulitis and osteomyelitis are the most frequent complications of fractures of the mandible and maxilla, because there is an abscessed tooth in the line of fracture. Since most fractures are compound fractures, infection may develop because of contact with oral secretions or outside air. The treatment of chronic osteomyelitis is still under debate. Some authors rely on antibiotics alone, while others advocate combination with surgery. But when infection occurs, establish proper drainage and administer antibiotics. Author treated a case of infected mandibular fracture with mandibular osteotomy, sequestrectomy, iliac bone graft and hyperbaric oxygen therapy, who had suffered suppurative osteomyelitis and mandibular nonunion following the open reduction of the mandibular fracture.

자력선별법에 의한 선탄의 탈황

이재장,전호석 江原大學校 産業技術硏究所 1995 産業技術硏究 Vol.15 No.-

Under the new environmental regulations announced by the government, utilities will have to cut their sulfur dioxide emissions by 60% from 1991 levels by the year of 1999. Sulfur dioxide emissions can be reduced prior to combustion by physical, chemical or biological coal cleaning. The new technology of high gradient magnetic separation (HGMS) offers the potential of economic separatoins of a variety of fine, weakly magnetic minerals including inorganic sulfur and many ash-forming minerals from coals. In the present paper, magnetic separation tests have been conducted on Korean anthracite and high-sulfur Chinese coal to investigate the feasibility of these techniques for reducing sulfur content from coals. In wet magnetic separation, the studied operating parameters include particle size, pH, matrix types, feed solids content, feed rate, number of cleaning stages and etc. The results shows that for wet separation, 60~70% of total sulfur was removed from coals with over 80% combustible recovery, on the other hand, for dry separation, 47.6% of total sulfur was removed from coals with 75% recovery.

Adaptive Feedback Linearization Control Based on Stator Fluxes Model for Induction Motors

Seok Ho Jeon  ,Jin Young Choi 제어로봇시스템학회 2002 Transaction on control, automation and systems eng Vol.4 No.4

Adaptive Feedback Linearization Control Based on Stator Fluxes Model for Induction Motors

Jeon, Seok-Ho,Park, Jin-Young Institute of Control 2002 Transaction on control, automation and systems eng Vol.4 No.4

This paper presents an adaptive feedback linearization control scheme for induction motors using stator fluxes. By using stator flukes as states, overparameterization is prevented and control inputs can be determined straightforwardly unlike in existing schemes. This approach leads to the decrease of the relative degree for the flux modulus and thus yields a simpler control algorithm than the prior results. In this paper. adaptation schemes are suggested to compensate for the variations of stator resistance. rotor resistance and load torque. In particular, the adaptation to the variation of stator resistance with a feedback linearization control is a new trial. In addition, to improve the convergence of rotor resistance estimation, the differences between stator currents and its estimates are used for the parameter adaptation. The simulations show that torque and flux are controlled independently and that the estimates of stator resistance, rotor resistance, and load torque converge to their true values. Actual experiments on a 3.7㎾ induction motor verify the effectiveness of the proposed method.

Preparation of column-shaped TiO2,SiOx nanoparticles by a diffusion flame reactor and their photocatalytic properties

Seok Ho Jeon,Tai Gyu Lee 한국공업화학회 2006 응용화학 Vol.10 No.1