제어체적 복사열정산을 위한 구분종좌표보간법의 오차 및 보정방안

차호진,송태호,Cha, Ho-Jin,Song, Tae-Ho 대한기계학회 2003 大韓機械學會論文集B Vol.27 No.6

The discrete ordinates interpolation method (DOIM) has shown good accuracy and versatile applicability for the radiation $problems^{(1,2)}$. The DOIM is a nonconservative method in that the intensity and temperature are computed only at grid points without considering control volumes. However, when the DOIM is used together with a finite volume algorithm such as $SIMPLER^{(3)}$, intensities at the control surfaces need to be calculated. For this reason, a 'quadratic' and a 'decoration' schemes are proposed and examined. They are applied to two kinds of radiation problem in one-dimensional geometries. In one problem, the intensity and temperature are calculated while the radiative heat source is given, and in the other, the intensity and the radiative heat source are computed with a given temperature field. The quadratic and the decoration schemes show very successful results. The quadratic scheme gives especially accurate results so that further decoration may not be needed. It is recommended that the quadratic and the decoration schemes may be used together, or, one of them may be applied for control volume radiative energy balance.

불규칙한 3차원 형상에 응용된 구분종좌표보간법

차호진,송태호,Cha, Ho-Jin,Song, Tae-Ho 대한기계학회 2000 大韓機械學會論文集B Vol.24 No.6

The Discrete Ordinates Interpolation Method (DOIM) is tested in three-dimensional enclosures. The radiative transfer equation (RTE) is solved for a linear source term and the DOIM is formulated for a gray medium. Several interpolation methods can be applied to the DOIM scheme. Among them, the interpolation method applicable to an unstructured grid system is discussed. In a regular hexahedron enclosure, radiative wall heat fluxes are calculated and compared with exact solutions. The enclosure has an absorbing, emitting and nonscattering medium and a constant temperature distribution. These results are obtained with varying optical depths (xD = 0.1, 1.0, 10.0). Also, the same calculations are performed in an irregular hexahedron enclosure. The DOIM is applied to an unstructured grid system as well as a structured grid system for the same regular hexahedron enclosure. They are compared with the exact solutions and the computational efficiencies are discussed. When compared with the analytic solutions, results of the DOIM are in good agreement for three-dimensional enclosures. Furthermore, the DOIM can be easily applied to the unstructured grid system, which proves the reliability and versatility of the DOIM.

위암환자의 수술전 , 후병기에 관한 임상적 비교 관찰 - 이학적소견 , 임상병리 검사소견 , 방사선학적 소견을 중심으로 -

최호순(Ho Soon Choi),배상철(Sang Cheol Bae),차호진(Ho Jin Cha),함준수(Jun Su Ham),이종철(Jong Chul Lee),이민호(Min Ho Lee),기춘석(Choon Suhk Kee),박경남(Kyung Nam Park) 대한내과학회 1987 대한내과학회지 Vol.33 No.2

N/A Gastric cancer is the most prevalent gastrointestinal tract malignancy in Korea. Although most effective treatment of gastric cancer is early detection and early resection of gastric cancer, but by the time the patient has symptoms, these tumors are usually advanced in stage. Gastric cancer staging methods for accessing surgical operability and resectability, the treatment planing and prognostic implications of gastric cancer patients are physical examination, liver function test, liver scan, abdominal ultrasonography, abdominal CT, angiography, lymphangiography, peritonioscopic examination, The reliability of physical examination, liver scan, abdominal ultrasonography and CT scan in preoperative staging of gastric cancer patients has been evaluated 77 patients with histopathologically proven stomach cancer (52 cases were performed ultrasonography, 24 cases were performed ultrasonography and CT scan). Who has admitted to department of internal medicine, college of Medicine, Han Yang university from December 1984 to June 1986. The results were as follows; 1) The mean age of gastric cancer was 56.6-year-old and the sex ratio of male to female was 3.3:1. 2) Preoperative staging of gastric cancer patients by physical examination and liver function test and UGI has no clinical significancy. 3) Liver scan, abdaminal ultrasonography and CT scan were 71.2% accurate, and 78% accurate, and 83.3% accurate, respectively, in detecting liver metastasis and sensitivity of liver scan, abdominal ultrasonography and CT scan in detecting liver metastasis were 77.7%, 34.3%, and 86.2% respectively (P<0.05). 4) Sensitivity of abdominal ultrasonography and CT scan in detecting lymph node metastasis were 20.3% and 65%, respectively (P<0.05). 5) Sensitivity of abdominal ultrasonography and CT scan in detecting other organs metastasis were 45% and 66.7%, respectively (P<0.05). 6) Metastasis to regional lymph node (14 patients), retroperitoneal lympho node, retrocrural lymph node, liver, pancrease, omentum and colon were well defined by CT scan than abdominal ultrasonography in 24 patients, 7) Diagnostic accuracy of CT scan staging was 66.7% (15/24) by correlation of surgical and pathological findings. 8) Although the usefulness of CT scan was limited in gastric wall-thick ness and differentiating lymph node metastasis from reactive lymph node hyperplasia, the pro-operative CT scan was useful in staging of gastric cancer and particularly in predicting metastasis to 1vmoh node and other organs.

강제대류에서 Vapor chamber heat sink의 열적 성능

김윤호(Yoon-Ho Kim),배수호(Soo-Ho Bae),차호진(Ho-jin Cha),구홍모(Hong-Mo Koo) 대한기계학회 2012 대한기계학회 춘추학술대회 Vol.2012 No.11

This paper presents thermal performance of vapor chamber heat sink under forced convection condition. Since the electronic industry has accelerated compact size, light-weight and highly integrated trend of electronic systems, thermal issues have been one of the most critical problems. A vapor chamber heat sink is one of the most efficient systems to improve the heat transfer performance without the increase of heat sink volume and fan flowrate. In order to evaluate thermal performance of vapor chamber heat sink, actual network device having CPU of high heat dissipation is chosen and temperature according to fan speed is measured. As a result, surface temperature of vapor chamber heat sink and CPU junction temperature shows good heat transfer performance with thermal resistance of less than 0.1℃/W. The thermal conductivity of vapor chamber is calculated about 5,000 W/mㆍK by using a CFD simulation.

후복막강내 충실성성숙성 기형종

박경남 ( Kyung Nam Park ),최호순 ( Ho Soon Choi ),기춘석 ( Choon Suhk Kee ),이중달 ( Jung Dal Lee ),박문향 ( Moon Hyang Park ),홍일 ( Il Hong ),차호진 ( Ho Jin Cha ) 대한소화기학회 1987 대한소화기학회지 Vol.19 No.2

A teratorna (C'reek teratos [):IonsterJ and onkoma [a swelling]) is a true tumor or neoplasm composed of multiple tissues of kinds foreign to the parts in which it arises, take different forms, either solid or cystic, and arise in an immediately prexial median or paramedian location. The retroperitoneal teratoma is a rare condition in only 10% of all retroperitoneal primary neoplasms. Among 10%, the incidence of malignant degeneration has been reported to be from 6 to 10 percent and mature solid retropertioneal teratoma is about 90 percent. About 200 cases has been recorded since Morgargnis first description in 1961. A 24-year-old woman complained left upper guadrant palpable mass. Roentgen study revealed typical conglomerated frame-like calcification in left abdomen. In addition to reporting a case of mature solid retroperioneal teratoma, we will present a review of the literature available on this subject.

이동통신 기지국 직접대기냉각용 에어필터의 성능평가실험

여국현(Kuk-Hyun Yeo),유경훈(Kyung-Hoon Yoo),차호진(Ho-Jin Cha),김용우(Yong-Woo Kim),최동규(Dong-Kyu Choi),이홍규(Henry Lee) 대한설비공학회 2006 대한설비공학회 학술발표대회논문집 Vol.2006 No.6

간 , 담도 및 췌장 : 췌장암의 임상적 고찰

기춘석(Choon Suhk Kee),박경남(Kyung Nam Park),이민호(Min Ho Lee),이종철(Jong Chul Lee),최호순(Ho Soon Choi),배상철(Sang Cheol Bae),차호진(Ho Jin Cha),함준수(Jun Su Ham) 대한소화기학회 1987 대한소화기학회지 Vol.19 No.2

N/A The diagnosis of pancreatic cancer is very difficult because the pancreas is located in the retroper- itoneum, symptoms are diverse, and physical findings are not specific. In the USA & western Europe, the incidence of pancreatic cancer has increased since 1930 and is the fourth most common cancer of all sites as a cause of death. Although recently, ERCP ultrasonogra phy (US) & computed tomography (CT) have been widely used for the diagnosis of pancreatic cancer is still difficult. The prognosis of pancreatic cancer is very poor because the retroperitoneal location of the cancer is unsuitable for diret palpation & the profuse lymphatics & venous drainage of the pancreas invite early & widespread dissemination of the tumor cells. In order to evaluate the incidence, epidemiology, clinical manifestations, laboratory findings & ERCP findings, the author analysed 91 cases of pancreatic cancer which were confirmed by surgery 8r ERCP at the Deparment of Internal Medicine, Hanyang University, College of Medicine between January 1972 & September 1986. The results were as follows 1) The pancreatic cancer was most prevalent in 6th & 7th decade (62.7%). Male to female ratio was 1.5:1, with male preponderance. 2) Epigastric pain was most common symptom complained (91%). Weight loss (88%), anorexia (61 %) & vomiting (42%) were also frequently noted in order of frequency. 3) The patient who had under 3 months duration of illness before confirmatory detection was found in 82.4% and those over 1 year duration in 4.4%. 4) The obstructive jaundice (23.1%) was the most common clinical impression of the patients followed by pancreatic cancer (16.4%), peptic ulcer disease (15.4%), pancreatitis (11%) & GB stone (5. Goyo). 5) In physical examination, hepatomegaly was palpable in 52% of patients. Jaundice (37%), abdominal mass (15%) & ascites (10%) were noted in order of frequency. 6) In laboratory findings, the elevated alkaline phophatase was most frequent in 79% of pathients. The elevated SGOT (62%), hyperbilirubinemia (55%) & anemia (32%) were frequently found in order of frequency. 7) In relation with diabetes mellitus, the patient of pancreatic cancer had the DM in 4%. The developmont of diabetes de novo is in 18%. 8) In the 91 patients who were diagnosed, the head of the pancreas was the most common site (68 %) of the tumor following by body (20%) & tail (12%). 9) Regional lymph node metastases were found in 57% & other metastaic sites were liver (53%), abdominal viscera (5%), adrenal (4%) & lung (3%) in order of frequency. 10) According to Fukumotos classification, the most common type was obstructive type (62.5%), followed by the stenosing type (29.1%), narrowing type (5.6%) & abnormal branching type (3.7%) 11) According to Takakis classification, Type 1 (obstruction or stenosis of the main pancreatic ctuct) was the most common (82.7%), followed by Type III (pancreatic dilatation) (9.3%), Type II (obstruction of Wirsung's duct or Santorini's duct) (4%), & Type IV (normal pancreatic duct) (4%).

이동통신 기지국 DAC용 에어필터의 성능분석실험

유경훈(Kyung-Hoon Yoo),여국현(Kuk-Hyun Yeo),차호진(Ho-Jin Cha),김용우(Yong-Woo Kim),최동규(Dong-Kyu Choi),이홍규(Henry Lee) 한국실내환경학회 2006 한국실내환경학회지 Vol.3 No.2

In recent European telecommunication base transceiver stations(BTS), a membrane laminated air filter is reported to replace a heat exchanger in order to cool internal digital units of BTS. The concept of using the air filter is for the direct ambient cooling (DAC) of BTS without heat loss generally found in the heat exchanger type BTS. In the present study, a performance evaluation experiment was conducted to investigate the pressure drop characteristics with dust loading and the particle collection efficiency of the air filter for the DAC of BTS. Finally, the long term operation lifetime of the air filter for BTS was suggested with a given fan rotation speed.

위염 및 소화성 궤양 환자에서 Aluminium Acetylglycyrrhetic Acid (Oriens�)의 치료효과

장현규,최호순,차호진,배상철,홍일,기춘석 최신의학사 1986 最新醫學 Vol.29 No.11

Cardiac Catabolic Factor 가 심장판막에 미치는 영향에 관한 연구

김경수,김정현,김성윤,임헌길,이정균,이방헌,강종명,차호진 대한내과학회 1987 대한내과학회지 Vol.32 No.1

It is recently known that the cultures of porcine heart valves & aorta secrete a factor that stimulate the degradation of cartilage matrix in a fashion similar that displayed by synovial catabolin. The heart valve factor also induces the release of chondroitin sulfate & hydroxyproline from isolated heart valve cultures. The present observations support the hypothesis that tissues producing catabolic factors may well be responsive to them and that these messengers may play a role in the cellular regulation of the degradation of intercellular macromolecules. We have investigated that the effect of cardiac catabolic factor on autologous or heterogous tissue by Masson`s trichrome stain and obtained following results. 1) The cardiac catabolic factors were released from the porcine heart valve media, the factors induced lysis its own intercellular matrix. 2) This cardiac catabolic factors showed the catabolic effect on human heart valve. 3) The porcine aorta showed resistance to cardiac catabolic factor. 4) The cardiac catabolic factors were not released from chordae tendineae & papillary muscle media.