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이희중 空軍士官學校 1989 論文集 Vol.26 No.-
This dissertation discusses some important theoretical problems which we ought to face when we describe the literary history. To this end, I, above all, study the fundamental differences between history and literary history. The concept of genre and period mainly constituting the literary history was minutely examined and the achievements of the contemporary Korean literary history, its limits and orientations were discussed reflectively.
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조영제를 이용한 다중시기 복부자기 공명 혈관 조영술에 있어서 디지털 감산 기법의유용성
이희중,염헌규,권재현,이상권,장용민,김용선,김용주,강덕식 대한영상의학회 2001 대한영상의학회지 Vol.45 No.2
목적: 복부 소화기계 혈관을 평가하기 위한 조영제를 이용한 다중시기 자기공명혈관 조영술 (magnetic resonance angiography. 이하 MRA)에 있어서 디지털 감산 기법의 유용성에 대해 알아보려 하였다. 대상과 방법: 소화기계 질환으로 조영제를 이용한 복부 MRA를 시행한 25명의 환자를 대상으로 하였다 MRA는 1.5-T MR 기기를 이용하여 3D turbo-FLASH 방법으로 시행하였다. 동맥기와 문맥기의 감산 MRA는 각각 동맥기 영상에서 비조영 영상, 문맥기 영상에서 동맥기 영상을 감산한 후 최대강도투사(maximum-intensity projection. 이하 MIP) 방법으로 3타원 재구성을 하여 얻었다. 감산과 비감산 MRA간의 전체적인 영상의 질을 비교하였고 동맥기와 문맥기 MRA에서 정상 소화기계 혈관의 보이는 정도를 분지 서열을 기준으로 점수화 하여 비교 분석하였다 또한 동맥의 이상분지와 문맥압 항진증 환자에서의 측부 혈관. 양성 혹은 악성 질환에 의해 폐쇄 또는 협착을 보인 비정상 문맥을 발견하는 정도를 함께 비교하였다 결과: 주관적인 영상의 질은 동맥기와 문맥기 모두 감산과 비감산 MRA간에 타이가 없었다 (p〉0.05). 동맥기 감산 MRA에서 비감산 MRA에 비해 좌위동맥과 상장간막동맥의 보다 말초의 분지가지 볼 수 있었으며 전테 대상 동맥의 평균에서도 감산 MRA에서 더 말초의 혈관가지 보였다(p〈0.05) 문맥기 감산 MRA에서는 상장간막정맥(p〈0.01), 비정맥(p〈0.05). 좌간문맥(p〈(0.05)에서 더 말초의 분지를 볼 수 있었으며 대상 정맥 전체의 평균에서도 더 말초 분지가보였다 (p〈0.01). 동맥의 이상분지가 있었던 7예,문맥의 폐쇄 또는종양 침범이 있었던 5 예는 감산 및 비감산 MRA에서 모두 발견되었다. 총 6명의 환자에서 문맥계의 측부 혈관이 발견되었으며 감산 MRA에서는 17개의 측부 혈관이 발견되었으나 비감산 MRA에서는 7개의 측부 혈관만 발견되었다. 결론: 조영제를 이용한 복부 MRA에 있어서 감산 기법은 영상의 질 저하가 없으면서 동맥과 문맥계 혈관을 감산 기법을 사용하지 않은 경우 보다 더 세밀하게 영상화할 수 있으며 특히 문맥 계의 측부 혈관의 발견에 우월하여 유용한 방법으로 생각된다 Purpose: To assess the usefulness of digital subtraction contrast-enhanced multi-phase magnetic resonance angiography (MRA) for evaluation of the vessels of the gastrointestinal system. Materials and Methods: Twenty-five patients who underwent abdominal MRA for evaluation of the vessels of the gastrointestinal system were included in this study MRA was performed using a 1.5-T scanner and the 3-D turbo-FLASH sequence. Subtraction images of the arterial and portal venous phases were obtained by subtracting arterial phase images from mask images and portal venous phase images from arterial phase images, respectively. Each set of images was processed using a maximum-intensity projection (MIP) algorithm to produce three-dimensional angiograms. We compared overall image quality and the visibility of normal and abnormal vessels between subtraction and non-subtraction MRA. Results: In terms of subjective image quality, subtraction and non-subtraction MRA was similar both the arterial and portal venous phases (p > 0.05). During the arterial phase, subtraction MRA visualized more peripheral branches of the left gastric and superior mesenteric arteries than non-subtraction MRA (p< 0.05), and during the portal venous phase, subtraction MRA demonstrated more peripheral branches of the superior mesenteric (p< 0.01), splenic (p< 0.05) and left portal vein (p< 0.05) than non-subtraction MRA. In addition, overall visibility of the arterial and portal venous branches was superior with subtraction MRAs than with non-subtraction MRA. Both of these detected all anomalous arterial branching (n = 5) and abnormal (encased or obstructed) portal veins (n = 5). Subtraction MRA visualized 17 portal venous collaterals in six patients, whereas non-sub-traction MRA visualized only seven collateral veins. Conclusion: In contrast-enhanced abdominal MRA, the digital subtraction technique permits visualization of more distal branches of the vessels of both the arterial and portal venous systems without significant degradation of image quality. The technique is particularly useful for the detection of portal venous collaterals in patients with portal hypertension.
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Step-Up 구조를 갖는 다층박막 초소형 구동소자의 초기변형 최소화에 관한 연구
이희중,강신일,Lee, Hee-Joong,Kang, Shin-Ill 대한기계학회 2002 大韓機械學會論文集A Vol.26 No.11
In the present study, a new anchor design was proposed to minimize the initial deflection of micro multi-layer cantilever beam with step-up structure, which is a key component of thin film micro-mirror array. It is important to minimize the initial deflection, caused by residual stress, because it reduces the performance of the actuation. Theoretical and experimental studies were conducted to examine the cause of the initial bending deflection. It was found that the bending deflection at the anchor of the cantilever beam was the primary source of initial deflection. Various anchor designs were proposed and the initial deflections for each design were calculated by finite element analysis. The analysis results were compared with experiments. To reduce the initial deflection a secondary support was added to the conventional structure. The optimal shapes were obtained by simulation and experiment. It was found from the analysis that the ratio or horizontal and vertical dimensions of secondary support was the governing factor, which affected the initial deflection.
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고온에 노출된 꼬막 (Tegillarca granosa; Linnaeus, 1758) 의 생리적 반응
이희중,송재희,정희도,박경일 한국패류학회 2021 The Korean Journal of Malacology Vol.37 No.1
This study examined the physiological responses of cockles exposed to thermal stress in order to optimize techniques for measurement of physiological alternations in cockles and understand the importance of thermal stress on summer mortality events. For these reasons, cockles acclimated to 25°C were exposed to 30°C, 35°C, or 40°C for 4h/day over eight days, and the condition index, nitric oxide (NO) concentration, burrowing rates and mortality rates were measured after each heat treatment. From the 1st day of exposure, and each day after, NO concentrations in cockles significantly increased when the temperatures was > 30°C. In contrast, decreases in phagocytosis rates were observed when specimens were exposed to 30°C from the 2nd day of exposure while the burrowing rates started to decline from the 6th day of exposure when exposed to > 35°C. In addition, the mortality rate of cockles exposed to 35°C for 5 days increased. This study confirmed that cockles exposed to temperatures above 30°C may experience physiological stress, possibly leading to death, depending on the exposure time.
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