샘물의 구조성 발색과 바이오미메틱스 섬유

권오경,고재운,최영희,이상아,Kwon, Oh-Kyung,Kouh, Jae-Oon,Choi, Young-Hee,Lee, Sang-A 한국의류산업학회 2006 한국의류산업학회지 Vol.8 No.2

서혜부 탈장에서의 초음파 조영술

권오경,정진향,박진영,장수일,Kwon, Oh-Kyoung,Jung, Jin-Hyang,Park, Jin-Young,Chang, Soo-Il 대한소아외과학회 2002 소아외과 Vol.8 No.1

초음파 검사는 수술 전 탈장 진단을 위한 안전하고 간편한 진단방법으로 본 연구에서는 서혜부 탈장의 진단 시 초음파 검사의 정확도와 잠복 탈장에 대한 초음파의 진단적 의의를 확인하고자 하였다. 1999년 3월부터 2000년 1월까지 경북대학교 일반외과학 교실에서 이학적 검사상 서혜부 탈장이 의심되어 술 전 확인을 위해 초음파 검사를 실시한 82명의 남아 (편측성 70예, 양측성 12예)를 대상으로 하였다. 서혜부 탈장 확진을 위한 초음파 검사의 진단 기준은 1)장관 탈장, 2)교통성 음낭수종, 3)초상돌기 확장, 즉 내서혜륜 부위에서 초상돌기의 너비가 4 mm 이상되는 경우로 하였다. 서혜부 탈장의 임상적 증상이 있었던 94개서의 서혜부에 대한 초음파 검사 결과, 장관 탈장 31개 (33%), 교통성 음낭수종 18개 (19%), 초상돌기 확장 38개 (41%), 탈장이 없는 경우가 7개 (7%)였다. 임상적 증상이 없었던 70개소의 서혜부는 초음파 검사상 장관 탈장 4개 (6%), 5개 (7%), 교통성 음낭수종, 초상돌기 확장 11개 (16%), 탈장이 없는 경우가 50개 (70%) 였다. 편측성 탈장의 증상을 가진 환아 중 20예 (28%) 가 초음파 검사에서 이학적 검사상 발견되지 않은 반대측 탈장이 발견되었으며 이들 중 5 개 (7%)는 탈장 없는 것으로 진단되었다. 양측성 탈장을 가진 12예 중 2예가 초음파 검사상 편측성 탈장으로 진단되었다. 초음파 검사상 서혜부 탈장으로 진단된 모든 예에서 서혜부 탈정 교정수술을 시행하였다. 164개소의 서혜부 중 이학적 검사에 의해 137개가 정확하게 진단되었으며 27개가 오진이었으므로 이학적 검사의 정확도는 83.5%였다. 탈장 교정수술을 시행한 107개의 서혜부 중 초음파 검사상 탈장으로 정확하게 진단된 경우는 104개이고 오진된 경우는 3예로 초음파 검사의 정확도는 97.2% 였다. 초상돌기 확대의 경우는 탈장의 증상이 있었던 38개소 중 36개, 증상이 없었던 11개 중 10개로 잠복 탈장의 경우 초음파 진단의 민감도는 93.8%였다. 서혜부 탈장의 진단에 있어 초음파 검사는 비침습적이며 높은 정확도를 가진 진단 방법으로 이미 임상적 검사상 확진된 탈장의 경우 간과하고 지나갈 수 있는 반대측 서혜부 탈장의 진단에 유리하며 본 연구와 같이 내서혜륜의 정상 직경의 상한을 4 mm로 정하면 술 전에 잠복 탈장을 비교적 쉽게 진단할 수 있어 불필요한 반대측 탈장 교정 수술을 줄일 수 있는 장점이 있다. 이에 서혜부 탈장이 의심되는 환아에 있어 상용 검사로 초음파 검사를 제안하는 바이다. Between March 1999 and January 2000, 82 boys with the diagnosis of inguinal hernias (12 bilateral and 70 unilateral hernias), underwent Ultrasound (US) examination of both sides of the groin, a total of 164 inguinal imaging prior to surgery. The patients ages ranged from 3 days to 12 years with a mean of 32.6 months. Ninty four examinations were on the clinically symptomatic side and 70 were on the asymptomatic side. The US criteria for the diagnosis of an inguinal hernia were as follows: 1) visceral hernia, the presence of bowel loops, or omentum in the inguinal canal, 2) communicating hydrocele, the presence of fluid in the processus vaginalis, 3) widening of patent processus vaginalis at the level of internal inguinal ring. The width of patent processus vaginalis at the level of internal inguinal ring over 4 mm is considered an occult hernia. Among the 94 symptomatic groins, US findings showed 31 (33%) visceral hernias, 18 (19%) communicating hydroceles, and 38 (41%) widening of the internal inguinal ring, and 7 (7%) groins without abnormalities. In 70 asymptomatic groins, there were 4 (6%) visceral hernias, 5 (7%) communicating hydroceles, 11 (16%) widening of the internal inguinal ring, and 50 (70%) groins without abnormalities. Among the 70 asymptomatic groins there were US abnormalities in 20 (28%). One hundred and seven groins with positive US findings were surgically explored. Among 107 operated sites, the operative findings were compatible with the US diagnosis in 104, a sensitivity for US of 97.2%. In patients with US findings of widening of internal inguinal ring (>4 mm), there was patent processus vaginalis in 36 out of 38 symptomatic groins and 10 of 11 asymptomatic groins. The sensitivity of US to the operative findings in widening of internal inguinal ring was 93.8%. For visceral hernia and communicating hydrocele, the sensitivity of positive US findings was 100%. Ultrasonography for inguinal hernias appears to be a rapid, reliable, and noninvasive screening diagnostic tool with high positive specificity. Therefore, we recommend the use of US as a routine diagnostic tool in pediatric patients with inguinal hernias and hydroceles.

반복세탁 및 전단·인정변형에 따른 텐셀직물의 피로도

권오경,이창미,김묘향,박희웅,Kwon, Oh-Kyung,Yi, Chang-Mi,Kim, Myo-Hyang,Park, Hee-Ung 한국의류산업학회 1999 한국의류산업학회지 Vol.1 No.3

This study was conducted to examine the fatigue phenomenon of mechanical properties in tencel fabrics by repeated washing & shear and tensile deformation. The obtained results are as follows. After performing repeated shear tensile deformation, RT of tencel showed higher increase rate than that of cotton and rayon, whereas its WT and EM was a smaller decrease rate than that of them. This means that tencel's resistance to tensile deformation was the greatest. In the repeated washing and shear tensile deformation, tencel's 2HB, 2HG and 2HG5 showed a remarkable increase rate. In terms of deformation frequency, the greatest change rate appeared at the time of 1000 cycles of repeated shear tensile deformation and 15 times of repeated washing. In the hand value and THV, KOSHI showed a higher increase rate for tencel than for cotton and rayon in both repeated washing and shear tensile deformation, and NUMERI showed a higher increase rate. In the THV the change rate of rayon and cotton could be rarely seen but for tencel, it decreased. tencel's change rate of thermal insulation value by materials was 1.08%, and it increased as the washing frequency increased, compared to the grey fabrics, whereas the change rates of cotton and rayon were 0.74% and 0.22%, respectively. The qmax decreased in the order of cotton>tencel>rayon as the washing frequency increased.

Properties of Zn O Varistor Fabricated by Seed Grain Method

권오경,마재평,백수현,Kwon, Oh Kyung,Mah, Jae Pyung,Paek, Su Hyon The Institute of Electronics and Information Engin 1987 전자공학회논문지 Vol.24 No.3

We investgated I-V cahracteristics and relationship between microstructures and electrical properties in the specimens fabricated by seed grain method for low voltage Zn O varistor. Breaksown voltage was mainly dependent on seed grain size, and could be cntrolled to 10V/mm -15V/mm by sintering temperature and time. In non-seed grain method breakdown voltage generally agreed with final grain size, but did not always agree with it by the change of barrier phase distribution in case of the method using seed grains.

수직관 흡수기의 물질전달에 미치는 계면활성제의 영향

권오경,윤정인,윤재호,Kwon, Oh-Kyung,Yoon, Jung-In,Yun, Jae-Ho 대한기계학회 2003 大韓機械學會論文集B Vol.27 No.5

This study was concerned with the enhancement of mass transfer by surfactant added to the aqueous solution of LiBr. Different vertical inner tubes were tested with and without an additive of normal octyl alcohol. The test tubes were a bare tube, groove tube, corrugate tube and inserted spring tubes. The additive concentration of normal octyl alcohol as a surfactant is about 0.08mass%. The Sherwood number was measured as a function of film Reynolds number 20~200. The experimental results were compared with those which use no surfactant. The enhancement of mass transfer by Marangoni convection effect which was generated by addition of the surfactant is proved for each testing tube Especially, it is clarified that the tube with the spring has the highest enhancement effect. A correlation of the experimental mass transfer data for the bare, groove, corrugate and insert spring tubes results expressed as the form of Sh=cㆍ Re$_{f}$ $^{n}$ .

마직물 및 마혼방직물의 온열특성에 대한 흡습의 영향

권오경,이참미,성우경,Kwon, Oh-Kyung,Yi, Chang-Mi,Sung, Woo-Kyung 한국의류산업학회 1999 한국의류산업학회지 Vol.1 No.2

The thermal properies of the pure linen fabrics available in the market and linen blended woven fabrics were measured at the moisture content of 0%, 20%, 40% and 60% using KES-F7 system (Thermo Iabo II type). The experimental properties were statistically analyzed by the rate of water absorbent. The main results were as follows; There is a positive correlation between the thermal insulation value (TIV) and thickness of pure linen fabrics and linen blended woven fabrics by water absorption. Whereas an negative correlation exists between the TIV and cover factor. There is a high positive correlation among the thermal conductivity (k), thickness and weight of pure linen fabrics and linen blended woven fabrics by water absorption. Wherase a high negative correlation exist between the k and air' permeability (Ap). There is a high positive correlation between the feeling of warmth/coldness and bulk density of pure linen and linen blended woven fabrics by water absorption. Wherase a high negative correlation exists between the feeling of warmth/coldness and porosity. There is a negative correlation between TIV and $q_{max}$ of pure linen fabrics and linen blended woven fabrics. The higher the rate of water absorbent, the lower the TIV. This means that TIV decreases by water absorption. As for the thermal property by rate of water absorbent $q_{max}$ and k increase by water absorption and reach max-value at 60% rate of water absorbent. The TIV decreases by water absorption and has +value at 0% rate of water absorbent, whereas it has -value with a feeling of coldness at 20%, 40%. and 60% rate of water absorbent.

H₂O/LiBr+HO(CH₂)₃OH계 공냉형 이중효용 흡수식 냉방시스템의 사이클 해석

권오경,문춘근,윤정인,Kwon, Oh-Kyung,Moon, Choon-Geun,Yoon, Jung-In 대한기계학회 1999 大韓機械學會論文集B Vol.23 No.2

A cycle analysis was achieved to predict the characteristics by comprehensive modeling and simulation of an air-cooled, double-effect absorption system using a new $H_2O/LiBr+HO(CH_2)_3OH$ solution. The simulation results showed that the new working fluid may provide the crystallization limit 8% higher than the conventional $H_2O/LiBr$ solution. With a crystallization margin of 3wt%(weight%), the optimal solution distribution ratio was found in the range of 36 to 40%. Variation of cooling air Inlet temperature has a sensitive effect on the cooling COP and corrosion problem. The simulation of heat exchangers with UA value revealed that the absorber and the evaporator are relatively important for an air-cooled system compared with the condenser and the low temperature generator. The effect of cooling air flow rate, circulation weak solution flow rate and chilled water inlet temperature were also examined. The new working fluid may provide the COP approximately 5% higher than the conventional $H_2O/LiBr$ solution.

분산형 지열시스템의 운전조건에 따른 성능 분석

권오경(Oh-Kyung Kwon),박경우(Kyoung-Woo Park),박차식(Cha-Sik Park) 호서대학교 공업기술연구소 2011 공업기술연구 논문집 Vol.30 No.1

본 연구에서는 분산형 지열 시스템에 대하여 기존의 지열시스템과 운전방법에 따른 성능 특성을 비교하였다. 복합 건물군에 대한 부하패턴을 분석하기 위하여 호텔과 사무소 건물에 대한 계절별 시간당 부하패턴을 조사하여 이를 바탕으로 연간 냉난방 에너지 소비량을 계산하였다. 호텔과 사무소로 구성된 복합건물군에 분산형 지열 시스템을 적용시 동절기와 하절기의 지열열교환기를 설치시 최대 부하기준으로 난방 7.5%, 냉방 5.2%의 냉난방 부하 절감 효과를 나타내었다. 특히, 환절기에 용도별 건물에 따라 동시 냉난방을 가동할 경우 냉방 21%,난방 25%의 시스템 효율 향상시키는 것으로 나타났다. The oerformance of a small scale distributed type geothermal heat pump system was compared with that of a conventional geothermal heat pmnp system for complex building groups. The conqjlex building group combined a hotel building and an office building was considered to analyze cooling and heating load The cooling and heating load appeared diffeent pattern with building types, when installed the distnbuted type geothermal heat pump system, it came out that the total heat load in the complex building groups decreased by heating load 7.5% and cooling load 5.2%,respectively. In addition, the present heat pump system raised the cooling COP 21% and the heating COP 25% compared to performance of the conventional geothermal heat pump system in the change of seasons.

WSRF기반의 TIGRIS 그리드 MPI 서비스

권오경(Oh-Kyoung Kwon),함재균(Jaegyoon Hahm),이필우(Pill Woo Lee) 한국콘텐츠학회 2008 한국콘텐츠학회논문지 Vol.8 No.1

본 논문에서는 WSRF기반의 TIGRIS 그리드 MPI 서비스를 기술하고자 한다. 본 서비스는 그리드 환경에서 MPI 작업을 실행하는 서비스이다. 다양한 종류의 MPI 라이브러리와 이기종의 계산 자원을 지원한다. 서비스의 주요 기능은 다음과 같다. 첫째, WSRF 기반의 동일한 작업 실행 인터페이스를 제공함으로써 특정 MPI 라이브러리의 사용법을 알지 못해도 작업을 실행할 수 있다. 작업을 실행하기 위해서 OGF에서 제안한 작업 제출 언어인 JSDL를 이용하여 사용자는 작업 실행이 가능하다. 두 번째, 두 개 이상의 자원에서 동시에 MPI 작업을 실행가능하게 하는 그리드 MPI 라이브러리를 지원한다. 세 번째, 사용자가 컴파일을 미리 하지 않아도 자동으로 컴파일 및 실행할 수 있게 한다. 서비스는 WSRF를 지원하는 글로버스 툴킷 기반으로 구현되었으며, 사용자 인터페이스는 웹 포털 및 CLI(Command Line Interface)를 제공한다. In this paper, we describe TIGRIS Grid MPI Service, which is the WS-Resource Framework (WSRF) based services to enable an MPI job to be executed on Grid environments. It covers heterogeneous compute resources and diverse MPI libraries. The main functionalities are as follows. First, it allows an MPI user to seamlessly launch a job without knowing how to use the specific MPI library. Secondly, it executes an MPI job on the cross-site resources by supporting the Grid-enabled MPI library such as MPICH-G2. Thirdly, it enables the user to launch a job using the source code without compiling. The service is implemented on top of the services of Globus Toolkit. We provide the user interface as a web portal and CLI(Command Line Interface).

확산접합 콤팩트 열교환기의 성능에 관한 실험적 연구

권오경(Oh-Kyung Kwon),차동안(Dong-An Cha),최미진(Mi-Jin Choi),윤재호(Jae-Ho Yun) 대한기계학회 2008 대한기계학회 춘추학술대회 Vol.2008 No.11

The objectives of this paper are to study the characteristics of heat transfer and pressure drop of the micro channel heat exchangers using diffusion bonding technology. Four types of heat exchangers are designed and manufactured, which are straight type, long dot type, splited wavy type and straight double side type. Heat transfer and pressure drop performance of each heat exchangers are measured in various operating conditions, and compared each other. The results show that the (j/f)<SUP>1/3</SUP> performance of splited wavy type and long dot type increases about 10.3% and 6.1% at the Reynolds number 470 compared to that of straight type, respectively. On the other hand, (j/f)<SUP>1/3</SUP> performance of straight double side type decreases 19.7%.