장방형내 저온 단일 수평 원관 주위의 동결현상에 관한 실험적 연구

정현철,윤재원,장원택,전승배,이동석,김병철 朝鮮大學校 機械技術硏究所 2007 機械技術硏究 Vol.10 No.1

An experimental study on water in a rectangular cavity with a horizontal cooling tube was carried out to investigate the flow character and thermal behavior in the system. Each experiment was performed with variation of initial temperature and cooling tube temperature. When the cooling tube temperature was -4℃, the supercooling phenomenon was observed regardless of the initial water temperature. And the case of cooling tube temperature was -6℃ with initial temperature was below 4℃, the supercooling phenomenon was also observedin the large region of the test section. When the cooling tube temperature was -10℃, the local region of supercooling phenomenon was observed during the freezing process. And the higher initial temperature was, the higher supercooling degree and the less difference of the ice thickness between upward and downward was observed. It is shown that by controllingthe supercooling phenomena and the cooling tube temperature, it would lead to an increase efficiency of ice making.

수직 냉각면이 있는 정방형내 성층유체의 열적거동에 관한 실험적 연구

정현철,윤재원,장원택,전승배,이동석,김병철 朝鮮大學校 機械技術硏究所 2007 機械技術硏究 Vol.10 No.1

This study was investigated by experimentals on the thermal behavior of stratified fluids in the square cavity with the vertical cooling surface by variation of initial temperature and cooling surface temperature and concluded as follows: 1. When the cooling surface temperature of the square cavity was -4℃. the supercooling phenomena was occurred every times regardless initial temperature of fluids and when -6℃ freezing was begun with out supercooling phenomena. 2. The higher the initial temperature was, the longer supercooling phenomena duration was, and the longer the supercooling phnomena was, the higher the temperature of the upper fluids was. 3. When the supercooling phenomena of water was occurred, the rate of temperature decrease of silicon oil was higher and when there was no supercooling phenomena, it was almost same the rate of temperature decrease.

흰쥐에서 심정지후 Pentoxifylline이 뇌의 허혈-재관류 손상에 미치는 효과

정시경,김영민,오동렬,최경호,박승현,이운정,박규남,유은영,이원재,김세경 大韓應急醫學會 1999 대한응급의학회지 Vol.10 No.2

Background: Two major events occurring in the cerebral hemodynamics after successful resuscitation from cardiac arrest are reactive hyperemia and postischemic hypoperfusion. In this study, we examined the effect of Pentoxifylline(PTX) on the rat brain following cardiac arrest. Methods: Fourteen rats were anesthetized and artificially ventilated. Cardiac arrest was produced by chest compression and clamping of tracheal tube for 3 minutes in ketamine anesthetized rats. Circulation was restored by standard cardiopulmonary resuscitation methods. In 7 rats, PTX 10mg/kg was infused at 10min after cardiac arrest(PTX group). In the other 7 rats, same amount of normal saline was infused(control group). Results: In both groups, hemodynamic variables, neurologic deficit(ND) score and histopathologic findings of hippocampal CA1 neurons were observed. Hemodynamic variables and ND score were not significantly different between two groups. Delayed ischemic neurons of hippocampal CA1 were decreased in PTX group(2.2±2.4%) compared with control group(9.1±1.2%). Conclusions: We conclude that PTX prevented development of delayed ischemic neurons in hippocampal CA1 after cardiac arrest. PTX may be useful in emergency situations following cardiac arrest.

내시경적 점막절제술 후 발생한 위천공의 성공적인 보존적 치료 1예

양정채,박은하,이준행,이풍렬,김재준,백승운,이종철 대한내과학회 2004 대한내과학회지 Vol.66 No.5

위장관 천공은 내시경적 점막절제술 후 발생할 수 있는 중대한 합병증으로 현재까지 이에 대한 치료 방법은 정립되지 않은 상태이다. 본 증례는 점막층에 국한된 위선암에 대한 내시경적 점막절제술 후 위천공이 발생한 경우로서 아주 작은 미세천공(microperforation)이었고, 최근 시도되고 있는 내시경적 클립 시술의 적응이 되지 못했다. 하지만 임상적인 복막염 발생 및 진행의 징후가 보이지 않아 금식, 광범위 항생제 투여 등의 보존적 요법으로 치료를 시행하였고, 시술 일주일 후 복막염의 발생이나 진행 없이 호전되어 퇴원하였다. 본 증례는 내시경적 점막절제술 후 발생한 미세 천공의 제한적인 경우에 한하여 수술이나 내시경적 치료를 하지 않고 보존적 요법만으로 성공적인 치료를 시행한 예로 문헌고찰과 함께 보고하는 바이다. The serious complication after endoscopic mucosal resection (EMR) was bleeding and perforation. Most of bleedings could be controlled by endoscopic procedure. However, the strategy of treatment for perforation was not established. A 60- year-old man was admitted to our center for EMR of gastric adenomatous lesion. After EMR, perforation in stomach was detected by peumoperitoneum on plain upright chest X-ray. We treated with conservative management such as withholding of oral intake, adminstration of broad-spectrum antibiotics, parenteral nutrition and close monitoring. There were no worsening clinical sings of peritoneal inflammation except mild leukocytosis during the in-hospital course. On the third hospital day after EMR, the patient resumed oral intake. The seventh hospital day, he was discharged. Our experience showed that selected small microperforation in stomach after EMR could be treated by not endoscopic procedures or surgical interventions but conservative management.

광선추적과 스펙트럼에 대한 교사와 중학생의 개념 유형 분석

이재봉,남경운,손정우,이성묵 한국과학교육학회 2004 한국과학교육학회지 Vol.24 No.6

본 연구의 목적은 중학교 교사와 학생들을 대상으로 광선추적과 스펙트럼에 대한 교사와 학생의 개념 유형을 비교하는 것이다. 본 연구에서는 7학년 '빛 단원에서 가장 중요하다고 생각되는 핵심개념은 광선추적과 스펙트럼에 의해 파악할 수 있다고 전제하고, 이에 대한 교사와 학생의 개념 유형을 조사하였다. 연구 대상은 서울ㆍ경기지역 과학교사 10명과 이들에게 배운 학생 328명이다. 모든 검사문항은 광선추적법과 스펙트럼 방법을 적용하는 문항으로 구성하였다. 연구결과 광선추적과 스펙트럼에 대한 교사와 학생들의 개념유형에는 차이가 있었다. 또한 대부분의 교사와 학생들은 상이 생기는 근본원리에 대하여 정확하게 알지 못하였다. 광선추적법을 알지 못하여 반사와 굴절에 의한 상을 찾을 때, 물체에서 나온 두 개 이상의 광선을 그려서 상을 찾는 경우는 거의 없었고, 하나의 광선으로 임의의 위치에서 상을 찾거나 평소 암기하고 있던 상의 위치를 표시하였다. 그리고 색에 대하여는 교사와 학생들은 개념을 이해하지 못하고, 교사들은 학생들에게 원리에 대한 설명 없이 현상을 제시하였다. 즉 교사와 학생들은 색에 대해서 단순 암기하고 있었다. The purpose of this study is to understand the types of teacher and student's concept on ray-tracing and spectrum in middle school. This study suggest key-concepts that is most important to "Light" unit in the seven grades : the ray-tracing and the spectrum. We examined the types of teacher and student's concept. We selected 10 teacher and 328 students who had learned by 10 teachers in Seoul and Gyeonggi. The problems were composed with the question item regarding all ray-tracing or the spectrum. From the analysis, it was found that the types of teacher and student's concept on ray-tracing and spectrum is different. The most of teacher and student didn't understand the basic principle of image formation. In case of context about formation of image by reflection and refraction, because they don't know ray-tracing, they do not try to find the position of the image by drawing two rays. Most of them used one ray comes from the one position of the object and indicated the position of image by memorized position. Also almost there was not a case which uses a ray tracing accurately. In the case of understanding color, they didn't understand the concept of color(or spectrum) and teachers represented to students the color phenomena without explanation of principles. In the result teachers and students would learn color science by rote.

단백질흡착을 막는 소프트콘택트렌즈에 관한 연구

조종수,정영일,나재운,김성호 朝鮮大學校 1997 藥學硏究誌 Vol.18 No.2

양말단에 이크릴레이트를 갖는 폴리에틸렌글리콜 미크로마(PEG macromer)와 또한 PEG macromer와 폴리하이드록시에칠메타아크릴레이트[P(HEMA)] 혹은 폴리(하이드록시에칠메타아크릴레이트-하이드록시프로메타아크릴레이트-비닐피롤리돈)[P(HEMA-co-HPMA-co-NVP)]와 상호침투된 망상구조의 시료가 소프트콘텍트렌즈의 알부민의 흡착을 막기위하여 제조되었다. PEG macromer의 중합으로 macromer의 다관능성기로 인하여 가교된 겔이 형성되었다. P(HEMA-co-HPMA-co-NVP)/PEG IPN계 콘텍트렌즈에서 PEG분자량이 중가할수록 알부민의 흡착량은 감소되었다. 또한 IPN제조시의 PEG의 농도가 짙을수록 알부민의 흡착량은 감소되었다. PEG macromer와 IPN하기전의 P(HEMA)계 및 P(HEMA-co-HPMA-co-NVP)계의 콘텍트렌즈에 비하여 PEG macromer와 IPN함으로서 렌즈의 착용감이 훨씬 상승되었다. Poly(ethylene glycol)(PEG) macromers terminated with diacrylate groups and interpenetrating polymer networks(IPN) composed of poly(hydrowyethyl methacrylate)(PHEMA) or poly(hydrowyethyl methacrylate-co-hydroxypropyl methacrylate-co-N-vinyl pyrrolidone)[P(HEMA-co-HPMA-co-NVP)]and PEG macromer were synthesized with the aim of abtaining protein adsorption resistant soft contact lens. Polymerization of PEG macromer. Crosslinked p(HEMA)or P(HEMA-co-HPMA-co-NVP) chains were interpenetrated into the cross-linked three-dimensional networks of PEG. It was found that albumin adsorption onto the contact lens prepared by P(HEMA-co-HPMA-co-NVP)/PEG IPN decreases with an increase of molecular weight of PEG. Also, it was found that albumin adsorption onto the both contact lens decreases with an increase of concentration of PEG macromer in the IPN preparation. There are also more adequate in the biointerness for the contact lens by P(HEMA)/PEG IPN or P(HEMA-co-HPMA-co-NVP)/PEG IPN than that by P(HEMA) or P(HEMA-co-HPMA-co-NVP).

BER을 경감하기 위한 직접파와 지연파를 분리, 합성하는 시스템

洪性一,邊健植,鄭宗宇,朴在云 東亞大學校 附設 情報通信硏究所 1993 情報通信硏究所論文誌 Vol.1 No.1

본 논문에서는 다중 경로에 따른 수신신호의 노화, 특히 이동통신에 대해서 문제가 되는 페이딩 대책으로 직접파와 지연파를 분리, 합성하는 적응 배열 안테나 시스템을 제시하고 분리된 직접파 출력 또는 지연파 출력만을 이용하는 시스템보다 두 신호를 합성한 시스템의 BER이 개선됨을 제시하였다. 시뮬레이션을 행한 결과 적응 배열 안테나가 적절히 동작하는 상황에 대해서는 분리된 출력을 적응적 Weight 조정을 하여 합성함으로써 직접파만을 이용하는 것보다 오율이 향상됨이 확인되었다.

간세포암종에 대한 간동맥 화학색전술 후 발생한 급성호흡곤란증후군

조윤원,이정미,최자윤,유동훈,차라리,오혜원,김홍준,민현주,김현진,정운태,이옥재,하창윤,이선영 이화여자대학교 의과학연구소 2013 EMJ (Ewha medical journal) Vol.36 No.1

Transcatheter arterial chemoembolization (TACE) has become an effective alternative treatment strategy for patients with inoperable hepatocellular carcinoma (HCC). Although TACE is relatively safe, acute respiratory distress syndrome associated with pulmonary lipiodol embolism is a rare and potentially fatal complication. We report a rare case of acute respiratory distress syndrome after TACE for inoperable HCC. A 75-year-old man, with huge HCC in right lobe, was treated by TACE for the first time. Seven hours after uneventful TACE procedure, he felt dyspneic and his oxygen saturation recorded by pulse oximetry (SpO2) fell to 80% despite of applying non-rebreathing mask. He underwent mechanical ventilation with a protective ventilatory strategy. We experienced a case of acute respiratory distress syndrome after TACE for HCC.

반복적인 경련을 동반한 아이소니아지드(Isoniazid) 중독환자의 치험 1례

이환,오동렬,정시경,김영민,이운정,김세경,이원재,최경호 大韓應急醫學會 1999 대한응급의학회지 Vol.10 No.2

Isoniazid(Isonicotinic acid hydrazide) is an antimicrobial drug used since 1952 as a first line agent for the prophylaxis and treatment of tuberculosis. Isoniazid is well known for problems in population having a high prevalence of isoniazid use for prophylaxis or treatment of tuberculosis. But intentional or accidental isoniazid overdose is uncommon. The ingestion of toxic amounts of isoniazid causes recurrent seizures, profound metabolic acidosis, coma and even death. In adults, toxicity can occur with the acute ingestion of as little as 1.5g of isoniazid. Doses larger than 30mg per kg often produce seizures. When ingested in amounts of 80-150mg per kg or more, isoniazid can be rapid fatal. 40-year-old woman having previous pulmonary tuberculosis ingested 7gram of isoniazid(140mg/kg) to attempt suicide approximately 30 minutes prior to visit to our emergency medical center. She had recurrent generalized tonicclonic seizures and metabolic acidosis. We report one patient treated with pyridoxine, which was equivalent to the amount of isoniazid ingested and administered as a intravenous dose and oral dose

전해산성수를 이용한 새로운 내시경 소독 시스템(Cleantop WM-1??)의 소독효율

이준행,이풍렬,송재훈,이남용,임윤정,장재권,김영호,김재준,백승운,이종철,최규완 대한감염학회 2001 감염 Vol.33 No.2

Background : Electrolyzed acid water (EAW) is a new liquid chemical germicide containing a mixture of oxidizing species and prepared by mixing a small amount of salt with tap water in an electrolyzer. We attempted an in-use evaluation of the high-level disinfection capability of Cleantop WM-1□, a new endoscope reprocessing system using EAW. Methods : Forty-seven flexible endoscopes were randomly collected just after upper endoscopic examinations and were disinfected using Cleantop WM-1□. Parts of the endoscopes without contact to EAW were disinfected with 75% ethyl alcohol. Immediately after the disinfection procedure, samples were taken from the biopsy channel (S-1), tip of the insertion tube (S-2), the umbilical cord (S-3), and the angulation knob (S-4). Results : In EAW-disinfected parts of the endoscopes, the culture-positive rates were 4.3% (2/47) in S-1 samples and 12.8% (6/47) in S-2 samples. In ethyl alcohol-disinfected area, the culture-positive rates were 2.1% (1/47) in S-3 samples and 25.5% (12/47) in S-4 samples. The colony counts of culture-positive samples ranged from 1 to 144. Pseudomonas aerugi-nasa was recovered from the angulation knob of an endoscope, but other contaminating organisms were mostly : normal flora or opportunistic pathogens. Conclusion : Although part of the endoscopes disinfected with 75% ethyl alcohol were contaminated with more organisms than EAW-disinfected areas, Cleantop WM-1□ showed a relatively good disinfection efficacy in reprocessing patient-used endoscopes. (Korean J Infect Dis 33:133∼138, 2001)