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알코올에 의한 간손상시 적혈구막 지질 과산화현상의 역할
김원호,김한수,강진경,백승운,박인서,문영명,전재윤,함기백,신용운,장학철,최홍재 대한소화기학회 1992 대한소화기학회지 Vol.24 No.2
The question of whether or not ethanol-induced liver injury is related to or accompanied by lipid peroxidation has been a subject of controversy. Short-term ethanol administration was shown by some to produce hepatic lipid peroxidation in rats, but very large doses of ethaol had to be used. Furthermore, some investigators failed to confirm these effects of ethanol. Fewer studies have explored the relationship between alcohol consumption and lipid peroxidation. In order to study this question and clarify the role of oxygen derived free radicals and lipid peroxidation of the RBC in inducing the alcoholic liver diseases, we measured the thiobarbituric acid reactivities in normal controls and patients with alcoholic liver disease. The subjects were divided into three groups according to the liver function tests and the amounts of alcohol drinking: group I-normal controls, group II-cases showing normal liver function test in spite of frequent alcohol drinking over 3 days per week and 45 g alcohol per one time, group III-patients with alcoholic liver disaesae, drinking alcohol over 4 times per week. The thiobarbituric acid reactive substances were measured as a marker of lipid peroxidation by the method of Uchiyama and Mihara. The colorimetric method was used by a measurment of malonyldialdehyde [MDA, nmole/㎖ (packed cells)] concentration. The results were as follows. The mean MDA concentrations of group Ⅲ was 1.67±1.01 nmol/㎖ (packed cells), which was significantly higher than those of group Ⅰ [0.73±1.02 nmol/㎖ (packed cells)] and group Ⅱ [1.01±0.39 nmol/㎖ (packed cells)]. The MDA concentrations was significantly correlated with total protein (r=0.47, p$lt;0.05), total cholesterol (r=0.49, p$lt;0.05), and frequency of alcohol drinking (r= 0.49, p$lt;0.05) in group Ⅲ. There was a significant difference in mean MDA concentration between the cases with normal serum albumin and cases with hypoalbumnemia in patients with alcoholic liver cirrhosis. These data suggest that lipid peroxidation might play a contributing role in the pathogenesis of alcoholic liver disease.
유한 배플 원통 진동체의 수중 방사 임피던스에 대한 실험적 연구
김원호,윤종락,Kim, Won-Ho,Yoon, Jong-Rak 한국음향학회 1994 韓國音響學會誌 Vol.13 No.2
본 논문에서는 원통형 압전 진동체에 대한 수중 방사 임피던스를 유한 배플 구조에서의 측정 결과와 무한 배플 구조에서의 이론 결과를 비교하여 방사 임피던스에 대한 배플의 영향을 규명하였다. 배플의 길이가 증가할수록 방사 임피던스의 측정치는 무한 배플에서의 이론치에 접하하며, 배플의 영항은 방사저항에서 보다 방사 리액턴스에서 더 지배적 임을 보인다. 따라서 음향 변환기의 설계시 무한 배플 구조에서의 방사 임피던스 이론 결과를 적용하기 위해서는 배플길이에 따른 임피던스의 보상이 수행되어야 한다. In this paper, the measured in-water radiation impedance of cylindrical piezoelectric radiator with finite baffle is compared to the existing theoretical result of that with infinite baffle and the effect of baffle on the radiation impedance is examined. Comparision between measurement and theoretical result of radiation impedance shows that the measured radiation impedance tends to be that of the infinite baffle as the baffle length increases. Another finding of the comparision in that the effect of baffle is more dominant in radiation reactance than in radiation resistance. Therefore, for the use of theoretical radiation impedance of infinite baffle on the design of acoustic transducer, the impedance compensation to the baffle length should conducted.