급냉응고/분말야금법으로 제조된 Al-Fe-V-Si 합금의 기계적 성질 (2) : 파괴기구에 관한 연구 Micromechanism of Fracture

이종철,이두영,이성학,김낙준 대한금속재료학회(대한금속학회) 1990 대한금속·재료학회지 Vol.28 No.4

This study is concerned with a correlation between the microstructure and the micromechanism of fracture processes in an RSP/PM Al-8.5Fe-1.3V-1.7Si alloy. The specimens were exposed to the temperatures ranging from 150℃ to 480℃ for 100 hours, followed by room temperature tensile tests, fracture toughness tests and void initiation tests. This RSP/PM Al alloy did not show any significant change in room temperature tensile strength, tensile elongation and fracture toughness even after exposure up to 425℃ for 100 hours. However, tensile elongation and fracture toughness decreased significantly after exposed to 480℃ for 100 hours. Detailed microstructructural analyses showed that the alloy ahs a band structure due to non-uniform distribution of the silicide dispersoids. After exposure to 480℃, the formation of θ-Al₃Fe phases occurs at band structure boundaries by the dissolution of coarse silicide dispersoids, resulting in a loss of ductility and fracture toughness. The micromechanical processes involved in void and microcrack formation were identified and quantified. The results are interpreted using a simplified ductile fracture initiation model based on the basic assumption that crack extention starts to occur at a certain critical strain over a microsturcturally significant critical distance. This model enables us to correlate fracture toughness and microstructure, confirming that the formation of θ-Al₃Fe phases is the main metallurgical factor which contributes to the embrittlement phenomenon after exposure to 480℃ for 100 hours.

내과 중환자실에서 위장관 출혈의 원인

이종철,김영호,문원,강태욱,김재준,박동일,최규완,백승운,이경수,류민규,이풍렬 대한소화기내시경학회 2000 Clinical Endoscopy Vol.21 No.4

Backgound/Aims: Gastrointestinal (GI) bleeding remains a common medical problem, with morbidity and mortality rates of GI bleeding in intensive care unit (ICU) believed to have remained unchanged. There has been no report about the etiology and clinical manifestation of GI bleeding in ICU in Korea. Therefore, we performed this study to determine the frequency, etiology, risk factors, and outcome of clinically significant GI bleeding that occurred after admission to ICU. Methods: We reviewed medical records of 1829 patients admitted to medical ICU in Samsung Medical Center from October 1994 to May 1999, Cases were enrolled the patients who developed GI bleeding more than 24 hours after admission to the medical ICU. The cases were compared with control populations: a set of ICU patients without GI bleeding matched with cases for age, gender, and length of ICU stay to evaluate the risk factors of GI bleeding. Results: Clinically significant GI bleeding, confirmed by endoscopy, occurred in 71 patients of 1,829 patients (3.9%) after a mean ICU stay of 14±2.6 days. Gastric ulcer bleeding was the most common source of GI bleeding, accounting for 29.6% of cases overall. There were no statistical differences in underlying disease, mechanical ventilator use, heparin or steroid use, prothrombin time, prophylactic drug use such as H₂. blocker and antacid use between cases and controls. However, thrombocytopenia (<50,000/mm³) was more common in cases who had GI bleeding than controls (P<0.05). Conclusions: Gastric ulcer was the most common cause of GI bleeding in ICU and careful attention was necessary to patients with thrombocytopenia (<50,000/mm³) in ICU.

민족문화영역의 관점에서 본 재중동포정책 방향

이종철 中央大學校 民族發展硏究院 2000 民族發展硏究 Vol.- No.4

競技力 水準別 테니스 競技內容 特性 比較

이종철,김재호,임차훈 단국대학교 2000 論文集 Vol.35 No.-

The purpose of this study is to compare the differencr performance levels of 2 big games ('98 US OPEN MEN'S FINAL, '98 KOREA GRANDPRIX VOCATIONAL FEDERATION MEN'S FINAL). We analyzed the important skills such as Service, Service return, Ground stroke, Volly, Passing shot and the results are as follow. 1. Total number of services are fewer in world class game than national class game, and winning percentage of service game, success for point ratio of first service, success ratio of first service, success for point ratio of second service are higher in world class game than national class game. 2. The number of services point happened more frequently in world class game than in national class game. Service point areas are distributed from left come to right corner properly in world class game, however, in national class game service point ar eas are concentrated only in the center or right corner. 3. Ground strokes were not almost tried in world class game, but ground stroke played an important roles in national class game. 4. The average rally by point was 1.94 times in world class game, and 7.6 times in national class game. 5. Volly was followed by service in world a class game, on the contraly, we couldn't see any patern in national class game. 6. There were much more of passing shot trial in world class game than in national class game, however, success for point is higher in world class game. 7. In general, they played offensively in order to get the point in a short time in world class game. Yet, they played defensively to get the point in a long time rally in a national class game.

심포지움 연제 : 심미회복과 협진치료

이종철 대한치주과학회 2005 대한치주과학회 학술대회자료집 Vol.2005 No.2

기능성 위장장애 환자의 위내용물 배출시간

이종철,박영태,최규완,조보연,고창순 대한핵의학회 1981 핵의학 분자영상 Vol.15 No.1

임신 및 각종 갑상선질환에서 갑상선 기능 판정에 관한 연구 : 혈청유리 T4의 진단적 의의에 관한 고찰 The diagnostic value of free thyroxine by RIA

이종철,유명희,윤휘중,신영태,정순일,조보연,이문호,이명철 대한핵의학회 1981 핵의학 분자영상 Vol.15 No.1

To evaluate the diagnostic accuracy of the measurement of free thyroxine(FT4) by radioimmunoassay, we measured free T4 and T4, T3, T3RU, TSH and TBG serum levels by radioimmunoassay in 18 healthy persons and 52 patients with various thyroid diseases and 11 normal pregnant women. The results are as follows. 1) In 19 cases of overt hyperthyroidism, T3, free T4 and FTI, T4/TBG ratio reflect hyperfunction in all cases. T4 is increased in 94%(18/19) and TBG and TSH are decreased in 79%(15/19). 2) In 8 patients with overt hypothyroidism, TSH is increased in all cases and free T4 and FTI is decreased in all cases. T4 is decreased in 87.5%(7/8), T3 is decreased in 75%(6/8) and T4/TBG ratio is decreased in 62.5%(5/8). 3) In 5 patients who are clinically in euthyroid state after treatment of hyperthyroidism, T4 free T4, FTI and TSH are in the normal range in all cases and T3 is normal in 60%(3/5) and slightly increased in 40%(2/5). 4) In 10 patients who showed clinically borderline hypothyroidism after treatment of hyperthyroidism, TSH is increased in all cases and free T4 and FTI are decreased in all cases, but T4 and T3, T4/TBG ratio are in the normal limit in all cases. So after treatment of hyperthyroidism, TSH, free T4 or FTI are recommended as optimal function test. 5) In normal pregnancy, free T4, FTI and T4/TBG ratio reflect normal function, but the other parameters unreliable due to the influence of increased TBG. Also TBG and TSH level in pregnancy is increased significantly compared with normal healthy control group. 6) The coefficients of correlation between T4 and FTI were 0.862(p〈0.001) and 0.685(p〈0.001) between free T4 and T4/TBG ratio. In most patients, diagnostic value of free T4 was comparable and even superior to FTI, so free T4 measurement can be used routinely with thyrotropin assay in the diagnosis of hypothyrodism or with T3 for the diagnosis of hyperthyroidism.

간질환 환자에 있어서 위내용물 배출시간 측정에 관한 연구

이종철,유대현,조석신 대한핵의학회 1989 핵의학 분자영상 Vol.23 No.1

상부 위장관 출혈을 동반한 위결핵 1예

이종철,김영호,이상수,문원,박동일,김재준,최규완,백승운,이풍렬,심상군,이경수,성인경,구진하,류봉춘 대한소화기내시경학회 2000 Clinical Endoscopy Vol.21 No.6

Gastric tuberculosis is quite rare and usually combined with pulmonary tuberculosis. Its diagnosis is so difficult as it is often unsuspected, We report a patient with gastric tuberculosis who presented with hematemesis in Korea, Upper endoscopy showed large, deep penetrating ulcer containing an exposed vessel and adherent clot in the body. Gastric biopsies revealed only chronic inflammation and no evidence of granuloma or malignancy. Diffuse mural thickening was noted on abdominal CT. The diagnosis was made postoperatively following gastrectomy for bleeding gastric ulcer. Microscopic examination of resected stomach showed peptic detritus and noncaseating granulomas. However, multiple caseating granulomas with Lagerhan's giant cells were found on the examination of lymph nodes. The patient was treated with antituberculous therapy for 12 months without any complications.

한국사회의 성격규정 논쟁 노트

이종철 건국대학교 상경대학 1987 商經論叢 Vol.- No.22