췌ㆍ담도질환의 내시경적 진단과 치료

김창덕 대한가정의학회 1994 Korean Journal of Family Medicine Vol.15 No.11

R407C의 온도구배와 과열도가 증발기 성능에 미치는 영향

김창덕,전창덕,이진호 대한설비공학회 2003 설비공학 논문집 Vol.15 No.10

R407C is considered as an alternative refrigerant of R22 for air conditioners. An experiment was carried out to investigate the characteristics of the evaporation heat transfer and pressure drop for refrigerant R407C flowing in a fin-and-tube heat exchanger used for commercial air-conditioning unit. The experimental data were useful in analyze the effects of the temperature glide and superheat for R407C. Test were conducted at the conditions of inlet refrigerant evaporation temperature of 7$^{\circ}C$, inlet air relative humidity of 50%, and refrigerant mass fluxes varying from 150 to 250 kg/m$^2$s. Representative results show that the heat exchanger performance for R407C evaporation is significantly affected by the change of the flow pattern from two-phase to super-heated vapor flow.

종격기종을 유발한 Mallory-Weiss 증후군 1 예

김창덕,현진해,주영만,황일순,천종철,김현위 대한내과학회 1989 대한내과학회지 Vol.36 No.2

Mediastinal emphysema may arise spontaneous or result from trauma. Esophageal perforation is the most common and important cause of mediastinal emphysema. Esophageal perforation may rarely occur in Boerhaave`s syndrome and Mallory-Weiss syndrome after vomiting. We experienced one case of Mallory-Weiss syndrome causing esophageal perforation and mediastinal emphysema. The patient was a 45-year-old male, who complained of vomiting, hematemesis and epigastric pain one day before admission. The gastroendoscopy revealed a deep hemorrhagic laceration (length, about 3㎝) in the mucosa of esophagogastric junction. The bleeding lesion was electrocoagulated. Two hours after electrocoagulation, he complained of dyspnea and retrosternal pain. So the roentgen examination (chest P-A and lateral view) was performed and revealed mediastinal emphysema and subcutaneous emphysema. He was transferred to chest surgery department and emergent operation was performed. So we report this case with review of literature.

만성 췌장염의 임상적 연구

김창덕,현진해,정문기 대한소화기학회 1998 대한소화기학회지 Vol.30 No.2

Background/Aims: Chronic pancreatitis is a chronic inflammatory process leading to destruction of exocrine tissue, fibrosis, and in some patients, loss of endocrine tissue. A multiplicity of causes may lead to chronic pancreatitis; however, chronic alcohol abuse appears to be the etiologic basis in 70-80% of adult patients. As the problem of chronic alcoholism has grown in the our country, the prevalence of chronic pancreatitis is increasing. However, few reliable studies have been performed concerning the clinical features of chronic pancreatitis in Korea. So we investigate the clinical characteristics and diagnostic accuracy of imaging studies in chronic pancreatitis. Methods: We analyzed the 91 patients with chronic pancreatitis who were diagnosed and managed at Anam Hospital, Korea University in Seoul frorn January 1988 to December 199i. Results: The sex incidence showed male predominance with a male to female ratio of 4.7:1 and peak age groups were 5th and 6th decades. Most common cause of chronic pancreatitis was chronic alcohol consumption(54.9%), and the other causes were biliary disease, anomaly of the pancreas, hyperlipidemia, and hyperparathyroidism. Cause was not identified in 20.9% of patients. Most of patients complaints abdominal pain(91%), and other eomplaints were indigestion(73.6%), weight loss (39.6%), jaundice(13.2%) or diarrhea(8.8%). Elevated serum amylase and fasting sugar level were shown in 39.6% and 29.7% of patients respectively. Sensitivity of abdorninal sonogram, CT scan, and ERCP were 59%, 78% and 89% in diagnosis of chronic pancreatitis respectively. CT scan was supetior to other methods in detection of pancreatic calcification and smail cystic lesions, and ERCP was superior to others in detection of minor ductal change. Twenty-one cases were accompanied by complications such as pseudocysts, biliary stenosis, duodenal obstruction, splenic vein thrombosis & pseudoaneurysm. Endoscopic treatment was given in 12 cases and surgical operation was performed in 19 cases due to complicaiton. Conclusions: Chronic alcohol comsumption is a major cause of chronic pancreatitis. CT and ERCP are essential diagnostic tool in evaluating morphological changes of chronic pancreatitis.

동일한 유입온도조건에서 R407C와 R22 적용 응축기의 특성비교

김창덕,전창덕,이진호 대한설비공학회 2003 설비공학 논문집 Vol.15 No.7

R407C is considered as an alternative refrigerant to R22 for air conditioners. An experimental investigation was made to study the characteristics of the condensation heat transfer and pressure drop for R407C flowing in a fin-and-tube heat exchanger used for commercial air-conditioning units. Experiments were carried out under the conditions of inlet refrigerant temperature of 6$0^{\circ}C$ and refrigerant mass flux varying from 150 to 250 kg/$m^2$s for refrigerant side. The inlet air has dry bulb temperature of 35$^{\circ}C$ , relative humidity of 50% and air velocity varying from 0.8 to 1.6 m/s. Experiments show that air velocity increased by 25% is needed for R407C than that of R22 for subcooling temperature of 5$^{\circ}C$, which resulted in air-side pressure drop increase of 28.8% for R407C as compared to R22. As a consequence, in order to provide the same design condition of a condenser, the fan requires higher electric-power consumption with R407C than that with R22.

응축기의 설계조건에서 공기측 열전달계수 및 압력강하 산출

김창덕,전창덕,이진호 대한설비공학회 2003 설비공학 논문집 Vol.15 No.3

An experimental study on the air-side pressure drop and heat transfer coefficient of slit fin-tube heat exchanger has been carried out. The data reduction methodology for air-side heat transfer coefficients in the literature is not based on a consistent approach. This paper focuses on new method of data reduction to obtain the air-side performance of fin-tube heat exchanger using R22 and recommends standard procedures for dry surface heat transfer estimation in fin-tube heat exchanger having refrigerant on the tube-side. Results are presented as plots of friction f-factor and Colburn j -factor against Reynolds number based on the fin collar outside diameter and compared with previous studies. The data covers a range of refrigerant mass fluxes of 150~250 kg/$m^2$s with air flows at velocity ranges from 0.6 m/s to 1.6 m/s.

SURFACE MODIFICATION OF POLY(ETHERETHERKETONE) FIBERS AND THEIR COATING WITH POLYPYRROLE

김창덕,Kurt E. Geckeler 한국고분자학회 1999 한국고분자학회 학술대회 연구논문 초록집 Vol.24 No.2

응축기의 설계조건에서 R22, R407C, R410A의압력강하 예측 및 실험

김창덕,박일환,이진호 대한설비공학회 2004 설비공학 논문집 Vol.16 No.1

An experimental study on the refrigerant-side pressure drop of slit fin-tube heat exchanger has been carried out. A comparison was made between the predictions of previously proposed empirical correlations and experimental data for the pressure drop on design conditions of condenser in micro-fin tube for R22 and its alternatives, R407C (R32/125/134a, 23/25/52 wt.%) and R410A (R32/125, 50/50 wt.%). Experiments were carried out under the conditions of inlet refrigerant temperature of 60℃ and mass fluxes varying from 150 to 250 kg/m2s for R22, R407C and R410A. The inlet air conditions are dry bulb temperature of 35℃, relative humidity of 40% and air velocity varying from 0.68 to 1.43 m/s. Experiments show that pressure drop for R410A and R407C were 17.8∼20.2% and 5∼6.8% lower than those of R22 respectively for the degree of subcooling of 5℃. For the mass fluxes of 200∼250 kg/m2s, the deviation between the experimental and predicted values for the pressure drop was less than ±20% for R22, R407C and R410A.

Oxynitride Films Deposition and Characteristics by Eximer Laser CVD

김창덕,김영호,신상우,김상영,성영권 대한전자공학회 1997 대한전자공학회 학술대회 Vol.1997 No.1

냉매의 불균일한 분배가 증발기의 성능에 미치는 영향

김창덕,이진호 대한설비공학회 2004 설비공학 논문집 Vol.16 No.3

An experimental investigation was conducted to study two-phase flow distribution in a T-type distributor of slit fin-and-tube heat exchanger using R22. A comparison was made between the predictions by previously proposed tube-by-tube method and experimental data for the heat transfer rate of evaporator. Experiments were carried out under the conditions of saturation temperature of 5℃ and mass flow rate varying from 0.6 to 1.2 kg/min. The inlet air has dry bulb temperature of 27℃, relative humidity of 50% and air velocity varying from 0.63 to 1.71 m/s. Experiment show that air velocity increased by 85.2% is need for T-type distributor with four outlet branches than that of two outlet branches under the superheat of 5℃, which resulted in air-side pressure drop increase of 130% for T-type distributor with four outlet branches as compared to two outlet branches.