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입력속도제어를 통한 전후진 파워시프트 변속기 해석모델 변속성능 개선
홍원선 ( Won Sun Hong ),김수철 ( Su Chul Kim ),김경욱 ( Kyeoung Uk Kim ) 한국농업기계학회 2016 한국농업기계학회 학술발표논문집 Vol.21 No.2
전후진 파워시프트 변속기는 트랙터 이용 시 로더작업 등에 자주 사용되는 변속기의 한 부분이다. 전후진 파워시프트 변속기의 사용은 다양한 전후진 작업의 사용이 증가하면서 필요성이 급증하였으며, 이에 따라 트랙터 변속기의 공급 및 사용이 급증하였다. 그러나 잦은 방향 변속은 트랙터 차체에 충격을 주어 손상의 원인이 되며, 이는 작업자의 안전 및 몸에 불필요한 충격으로 건강에 무리가 된다. 이에 본 연구는 전후진 파워시프트 변속기 내부로 유입되는 속도를 제어함으로 방향 변속을 시 발생하는 변속 성능을 개선시키고자 해석모델을 개발하여 입력속도에 따른 변속성능개선 효과를 살펴보았다. 이를 위하여 전후진 파워시프트 변속기가 장착된 농용 트랙터를 대상으로 해석모델을 만들고, 입력속도 제어를 하여 변속성능이 향상됨을 확인하였다. 해석모델은 엔진, 클러치와 기어를 포함한 전후진 파워시프트 변속기, 피스톤, 댐핑 및 강성, 기어비, 비틀림댐핑계수, 마찰계수의 요소들로 구성되어있으며 대상 트랙터의 제원을 이용하였다. 엔진의 관성량, 마찰판의 마찰계수 등과 같이 제원을 통해 얻을 수 없는 수치는 시행착오법으로 구하였다. 완성된 해석모델은 실차 실험 결과와 비교하여 차량을 이상적으로 모방하는 것을 검증하였다. 대부분의 경우 입력속도 제어를 통한 변속성능의 개선 효과가 있었으나, 급작스러운 입력속도의감소나 증가는 제어 전의 변속성능보다 좋지 않았다. 초기입력속도가 클수록 변속충격의 개선정도는 큰 경향이 있었으나 변속시간은 개선의 효과가 크지 않았다.
정성희,정훈용,김태원,김청수,강경훈,송현순,황창연,명승재,양석균,홍원선,김진호,민영일,Jung Sung-Hee,Jung Hwoon-Yong,Kim Tae Won,Kim Chung Su,Kang Gyung Hoon,Song Hyun Sun,Hwang Chang Yeon,Myung Seung-Jae,Yang Suk-Kyun,Hong Weon-Seon,Kim J 대한위암학회 2002 대한위암학회지 Vol.2 No.1
Carcinomas of the stomach can spread to adjacent structure by local extension or metastasize to lymph nodes, peritoneum and distant organs. However, the incidence of metastatic bladder cancer originated at the stomach is very rare. A fifty-five year-old man admitted complaining of epigastric pain for 2 months. A large ulceroinfiltrative lesion was seen in the low body, which was confirmed poorly differentiated adenocarcinoma by histological examination. Abdominopelvic CT scan showed wall thickening at the greater curvature side of gastric body and urinary bladder. Urine cytology was negative. By transurethral resection of bladder, he was diagnosed as metastatic adenocarcinoma of the bladder. We report a case of stomach cancer with metastasis to urinry bladder.
양성 및 악성복수의 (惡性腹水) 의 감별에 있어서 복수 CEA 치 측정의 진단적 (診斷的) 의의
유병철 ( Byung Chul Yoo ),임정순 ( Jung Soon Im ),홍원선 ( Won Sun Hong ),윤용범 ( Yong Bum Yoon ),김정용 ( Chung Yong Kim ) 대한소화기학회 1981 대한소화기학회지 Vol.13 No.1
Cytologic examination of ascites has been widely used for the diagnosis of malignancy, but its sensitivity is limited, and false positive findings occur occasionally. Recently, it has been suggested that malignant ascites contains increased concentration of carcinoembryonic antigen. The present study analyzed CEA levels of serum and ascites in g9patients with benign or malignant ascites, and the results were as followings: The mean CEA level of R8 henign ascites was 2. () ng/ml with a standard deviation of I. 38ng/ml, and the highest CEA level did not exceed 10 ng/ml. Ascites CEA levels in Rl patients with malignant peritonitis(mean level with 142. 3 ng/ml) were significantly higher than in patients with benign ascites and in 18 patients the levels exceeded 10 ng/ml. In patients with primary liver cancer, ascites CEA levels were not higher significantly than in patients with benign ascites. 2 In the malignant peritonitis group, there was a good correlationship(correlation coeffic- ient; 0. V2) between serum and ascites CEA levels, and gastrointestinal tumors, usually cons- idered CEA-producers, tended most often to have increased CEA levels of ascites. 3. In the pl patients with malignant peritonitis, cytologic examination was positive in 10 patients(32%), whereas ascites CEA levels were above 10 ng/ml in 18 patients(58%). Combi- ning the two methods increased the diagnostic accuracy up to 77%. Fourteen of g1 malign- ant ascites were negative by cytologic examination and detected only by CEA assay of ascites. Weconcluded from these results that CEA assay of ascites is a useful diagnostic adjunct to cytologic examination in the differentiation of benign and malignant ascites.
김진천,홍원선,민영일,정훈용,하현권,양석균,정성애,유창식,이미화,원선영,김해련,최승목,김해경 대한소화기학회 1998 대한소화기학회지 Vol.30 No.4
Background/Aims: In recent years, the pattern of tuberculosis has been changed, demonstrating that extrapulrnonary tuberculosis appears to be increasing. The aim of this study was to investigate the clinical features to predict the factors related to the development of complications in patients with intestinal tuberculosis. Methods: A total of 95 patients with intestinal tuberculosis treated at the Asan Medical Center from June, 1989 to November, 1995 were included. The clinical characteristics of the patients cured by antituberculous medication alone were compared with those of patients who underwent operation due to complications developed during antituberculous medication. Results: Eighty one patients were treated with antituberculous drugs, among whom 66 patients(81%) were cured by antituberculous drugs alone. The reaining 15 patients(19%) received operations for the complications that developed during antituberculous medication. The median period from the beginning of antituberculous medication to the development of complications was 3 months. There was no significant difference in clinical features between the two groups except the location of the disease. Small bowel was evaluated radiologically in only 30 patients, of whom 15 patients revealed small bowel lesions. Six out of 15 patients(40%) with small bowel lesions had the perforation of bowel, while none of 15 patients(0%) without small bowel lesions experienced it(p$lt;0.05). Conclusions: Intestinal tuberculosis patients having small bowel lesions showed a tendency to develop bowel perforation more frequently than in those without small bowel involvement. However, to draw a definite conclusion whether small bowel involvement is the true risk factor for perforation, a prospective study should be performed.
윤광희,홍원선,민영일,정훈용,방성조,김해련,양석균,주연호,송병철,원선영 대한소화기학회 1999 대한소화기학회지 Vol.33 No.3
Autoimmune hemolytic anemia is a rare complication of ulcerative colitis. We experienced two cases of ulcerative colitis combined with autoimmune hemolytic anemia. A 17-year-old man and a 34-year old woman responded to steroid therapy very well. In discussion, we summarize the cases reported in English literatures with attention to the etiology and treatment of autoimmune hemolytic anemia.
Helicobacter pylori로부터 분리한 마이크로소옴의 ATPase 활성
김진호,김혜원,민영일,홍원선,명승재,양석균,정훈용,조형진,사공정,박승필 대한소화기학회 2000 대한소화기학회지 Vol.36 No.6
Background/Aims: Helicobacter pylori (H. pylori) is unique in its ability to persist in acidic environment. The main mechanisms to survive in low pH are to produce large amounts of urease and to have ATPases. This study was performed to invetigate the characteristics of ATPases of H. pylori. Methods: ATPase activity of microsomes prepared from H. pylori (ATCC 43504) was measured by enzyme-coupled assay. The effects of pH, sodium azide (NaN3), N,N-dicyclohexylcarbodiimide (DCCD), diethylstilbestrol (DES) and bafilomycin on the microsomal ATPase activities were determined. We also investigated the effect of nigericin on the ATPase activity. Results: The ATPase showed maximum activity at pH 5.5. The activitiy was decreased by 29%, 38% and 42% with the addition of NaN3, DCCD and DES, respectively. Bafilomycin had little effect on the ATPase activity. ATPase activity was decreased with the addition of DES dose-dependently, while it was increased by nigericin dose-dependently. Conclusions: These results suggest that cell membrane of H. pylori possesses two types of proton pumps, F-type and P-type ATPases, which act as H+ ATPase.
골수로의 원격전이를 동반한 위장의 저등위 점막연관성 림프조직림프종 2 예
김진호,장혜숙,민영일,홍원선,명승재,이미헌,양석균,강경훈,정훈용 대한소화기학회 2000 대한소화기학회지 Vol.36 No.5
Extranodal mucosa-associated lymphoid tissue (MALT) lymphoma constitutes most of the low-grade gastric lymphoma and almost 50% of all gastric lymphoma. The specific recirculation pattern might explain the tendencies of MALT lymphomas to remain localized and to recur preferentially within the gastrointestinal tract. It was known that the rate of gastric MALT lymphoma with bone marrow involvement was low, as less than 10%. We have experienced two patients who presented with nonspecific abdominal pain and dyspepsia. They were diagnosed to have gastric low-grade MALT lymphoma with bone marrow involvement at the time of presentation. The endoscopic findings showed irregular ulcerations. Microscopically, there was monotonous lymphoid infiltration with lymphoepithelial lesions which were consistent with low grade MALT lymphoma. Both patients showed H. pylori-associated chronic gastritis. The results of their bone marrow biopsy showed focal infiltration of neoplastic lymphoid cells. We report two cases of primary gastric low-grade MALT lymphoma with the bone marrow involvement.