온도 유지시간 제어를 적용한 하이브리드 분말 압출 공정을 통한 요구 특성의 스퍼기어 제조

이경훈(Kyung Hun Lee),황대원(Dae Won Hwang),김병민(Byung Min Kim) 대한기계학회 2011 大韓機械學會論文集A Vol.35 No.8

본 연구는 압출 시 성형온도를 유지하여 Zn-22Al 합금분말의 성형성을 향상시키는 하이브리드 분말 압출 공정의 개발 및 온도 유지시간이 압출된 스퍼기어의 기계적 특성에 미치는 영향을 조사하기 위해 수행되었다. 피치원 지름 1.8mm 의 소형 스퍼기어는 압출온도 290, 300, 310℃에서 성형되었다. 볼밀시간 32h 의 Zn-22Al 합금분말을 압출온도 310℃에서 압출 시 표면 결함이 없는 소형 기어가 제조되었다. 경도분포는 기어 중심부와 치형부에서 불균일하였고 소결공정 후 내부 변형에너지의 차이로 인해 내부균열이 발생하였다. 위와 같은 문제를 해결하기 위해 온도 유지시간 제어를 이용한 하이브리드 압출 연구를 수행하였다. 압출된 스퍼기어의 평가는 압출하중, 비커스 경도 및 치수정밀도 측정을 통해 이루어졌다. 온도 유지시간 15min 에서 압출된 스퍼기어의 기계적 성질이 가장 우수하였다. In this study, a hybrid powder-extrusion process involving the control of temperature dwelling time for improving the formability of Zn-22Al powder was developed and the effect of dwelling time on the mechanical properties of a spur gear with a pitch circle having a diameter of 1.8 mm was investigated. General extrusion experiments were carried out at different temperatures such as 290, 300, and 310°C. Spur gears with good qualities and without any surface defects were obtained in the case of extrusion temperature of 310°C and ball-milling duration of 32 h. The Vickers hardness distribution was non-uniform, and after the sintering process, an internal crack was generated because of the different deformation energy between gear central part and teeth. To overcome the abovementioned problems, research on controlling the dwelling time of the extrusion temperature in the powder-extrusion process was carried out. Good-quality spur gears were obtained when the dwelling time was 15 min.

간질환환자의 위내용물 배출시간에 관한 연구

함준수(Joon Soo Hahm),이동후(Dong Hoo Lee),박경남(Kyung Nam Park),이민호(Min Ho Lee),이종철(Jong Chul Rhee),기춘석(Choon Suck Kee),유대현(Dae Hyun Yoo) 대한소화기학회 1989 대한소화기학회지 Vol.21 No.2

N/A Gastric emptying time(GET) is influenced by several factors, such as neura), hormonal and composi- tion and physiochemical properties of food. The patients with delayed GET have some upper gastrointestinal symptoms such as recurrent nausea, vomiting, postprandia! Bloating, anorexia, and iveight loss. And also, almost of acute hepatitis and a part of chronic ]iver disease patients have similar symptoms of the patients with delayed GET. Therefore We performed GET measurement in liver disease patients to identify the relationship between nonspecific upper gastrointestinal symp- toms and gastric emptying function. The resu]ts are as followings; 1) Total ]iver disease patients are 28 in number, composed of acute hepatitis 3, chronic hepatitis 18, liver cirrhosis 7. 2) The GET(T1/2) of liver disease patients was delayed significantly than that of the normal volunteers. (Mean+SE;120.8+6.6 vs 89.4+5.9 mins.) 3) The GET of the symptomatic patients (N = 20 ) ivas 128.3+6.8 mins (Mean+SE), and that of the asymptomatic patients (N =8) was 101.8+13.2 mins. The symptomatic patients have delayed GET in 10 patients and asymptomatic patients have delayed GET in 3. 4) The GET of the patients who have elevated serum transaminase level higher than twice of normal is delayed significantly than that of the patients who have serum transaminase level lower than twice of normal. (Mean+SE; 143.4+2.6 vs 110.0+7.4 mins.)

중골 골내지방종에 의한 병적골절 : 증례 보고 A Case Report

민경대,허일 순천향의학연구소;Soonchunhyang Medical Research Institute 2004 Journal of Soonchunhyang Medical Science Vol.10 No.2

Intraosseus lipoma is a very rare benign tumor of bone and most commonly reported in the metaphysis of the long bones. There are a few reports about intraosseus lipoma of the calcaneus but we cannot found the literature concerning the pathologic fracture caused by intraosseus lipoma of the calcaneus. A case of an intraosseus lipoma of the calcaneus causing pathologic fracture in 40-year-old male is described.

중족골 단축증 일단계 신연술 : 증례 보고 A Case Report

민경대,권혁룡 순천향의학연구소;Soonchunhyang Medical Research Institute 2004 Journal of Soonchunhyang Medical Science Vol.10 No.2

Congenital shortening of the matatarsal bone has both functional and cosmetic problems. The most widely used surgical correction techniques are either one-stage lengthening with intercalary bone graft or gradual lengthening by callotasis using external fixator. Authors present the case of 21-year-old female patient with brachymetatarsia who treated by one stage lengthening without bone graft or external fixator.

오차드그래스(Dactylis glomerata L.)의 품종에 따른 종자유래의 캘러스 형성률과, 캘러스 크기 및 식물체 재분화 효율의 비교

배은경,이인애,김기용,이병현,손대영,이효신,정민섭,조진기 Plant molecular biology and biotechnology research 2002 Plant molecular biology and biotechnology research Vol.2002 No.-

Comparison results of callus formation ratio from seed explants, callus sizes, regeneration ratios from callus and regeneration efficiency [calculated by following formular; callus formation ratio(%) × regeneration ratio(%)/100]for 27 ochardgrass (Dactylis glomerata L.)varieties imported and Hapsung 2 developed in Korea are as follows; 1. Among ochardgrass varieties showing more than 50% callus formation ratios, the descending order of callus formation ratio after bedding the seed explants for 4 weeks was 93>Sparta>Pizza>Condor>Lidaglo>Glorus>Hapsung2>Frode. 2. The callus sizes after bedding for 4 weeks were in the range of φ 0.43cm~4.2cm in which there was 10 times size difference between the largest one and the smallest one but most of them were between φ2.5cm~4cm. 3. The regeneration ratio from callus among varieties were in the range of 0~36% and descending order of the upper 6 varieties was Plano>Akimidori>Justus>Lidacta>Currie>Hall mark. 4. The regeneration efficiency which is calculated by the ratios of regeneration from seed explant numbers was between 0 to 17.4% among which Justus showed the highest value in the 4-week treatment. 5. The correlation between callus formation ratios and the callus sizes, callus formation ratios and regeneration efficiency, and callus sizes and regeneration efficiency were r=0.5765, r=0.6365 and r=0.6246, respectively in 4-week callus and all the correlations were significant on the 1% level. 6. In 6-week callus, the descending order callus formation ratios from seed sxplants for the best 6 varieties was Condor>Sparta>93M>Justus>Potomac>Lidaglo>Frode. 7. The callus sizes formed were between φ1.5~5.7cm in which Sparta, the largest one of φ5.7cm was five times larger than the smallest one. The callus size of the control variety. Hapsung 2 was φ3.8cm, which belonged to larger size. 8. Regeneration ratio showed a great deviation among varieties from 6-week old calli by showing from 0% to 100% in which all the calli were regenerated in Plano while no callus was regenerated in Juno, 9. The range of regeneration effciency was between 0~28% among varieties in which the values from 6-week callus treatment were larger than those from 4-week callus treatment. Especially, the value of Potomac in 6-week was 3 times larger than that in 4-week. 10. The correlation between callus formation ratios and the callus sizes, callus formation ratios and regeneration efficiency, and callus sizes and regeneration effciency were r=0.8369, r=0.6683 and r=0.5937, respectively in 6-week callus, and all the correlations were significant on the 1% level.

간경변 환자에서 Oro-cecal Transit Time의 측정

원경준,이준,변유미,조민근,조주연,서정균,김영대,박찬국,김만우 朝鮮大學校 附設 醫學硏究所 2008 The Medical Journal of Chosun University Vol.33 No.2

Background: Neurotransmitter like substances in the gut have been proposed to contribute to the overall portal systemic encephalopathy (PSE). The source of the ammonia in patients with PSE is mainly the small bowel, as a result of the conversion of glutamine in the diet to glutamate and ammonia. PSE is highly responsive to changes in diet, to antibiotic therapy and to ingestion of nondigestible disaccharides such as lactulose. This study was performed to evaluate the relationship between PSE and oro-cecal transit time. In addition, performed to evaluate the effect of severity, cause, complications of liver cirrhosis on oro-cecal transit time. Methods: Between August 2006 and February 2007, 48 cirrhotic patients consecutively was enrolled in study their oro-cecal transit time after informed consent was obtained. A non-invasive hydrogen breath test was used to study oro-cecal transit time (OCTT). Result: The OCTT were delayed in cirrhotic patients with PSE compared without PSE (123.3 ± 42.7 min vs 170.0 ± 58.3 min, p<0.05). OCTT tended to prolongate further as the damage in the liver got worse, nevertheless the result was statistically meaningless (p<0.111). Neither presence of ascites or cause of PSE had any influence on gastrointestinal transit. Conclusions: Cirrhotic patients with PSE have more delayed OCTT than without PSE. Further research is needed to find out the relationship between OCTT and severity of liver cirrhosis.

제 1형 신경섬유종증 환자에서 발생한 위장관 간질종양 1예

원경준,이준,변유미,조민근,한경택,김원,홍란,임성철,김경종,김영대,박찬국,김만우 朝鮮大學校 附設 醫學硏究所 2007 The Medical Journal of Chosun University Vol.32 No.2

Gastrointestinal stromal tumor (GIST) is the most common non-epithelial neoplasm arising in the gastrointestinal tract, but this tumor is rarely seen in association with type l neurofibromatosis (NFl) Generally, the majority of GISTs are isolated neoplasm and they are sporadically found in the stomach, but the GISTs in NFl patients are usually multiple and usually found in the small intestine. We report a case of multiple GISTs in the jejunum of a 63-year-old woman diagnosed as NFl accompanied by complication of gastrointestinal bleeding, In this case, Patient had multiple cafe-au lait spots and neurofibroma on skin and had freckling on axilla and groin, and then, we made a diagnosis of NFl. Gastrointestinal bleeding is controlled by resection of multiple GISTs. Generally, only 3-5% of all gastrointestinal bleeding comes from the small bowel. Causes of small intestinal bleeding are angiodysplasia, neoplasm, NSAIDs induced ulcer etc. but, If patients have NFl accompanied by complication of gastrointestinal bleeding, GISTs on small bowel must be considered.

중소기업형 통합일정관리 모듈의 개발

양성민,유대훈,송경동,강주선 경성대학교 생산기술연구소 1996 생산기술연구지 Vol.3 No.-

This research is performed for the purpose of helping small and medium enterprises in Pusan Korea through developing a Total Scheduling Module(TSM) considering their practical environments. The TSM consists of four sub-modules : a basic information sub-modules, a marketing information sub-module, an inventory control sub-module and a production control sub-module. And the TSM is developed for Network version under Client/Server environment.

한국판 대칭 및 정리정돈 성향 척도(K-SOAQ)의 표준화 연구

차경렬,임준석,박준영,이수영,김광욱,노대영,김세주,구민성,김찬형 大韓神經精神醫學會 2008 신경정신의학 Vol.47 No.3

Objectives : The Symmetry, Ordering and Arranging Questionnaire (SOAQ) has been reported as a valid tool for the assessment of symmetry, ordering and arranging compulsive behaviors of patients with obsessive compulsive disorder. It was introduced by Radomsky and Rachman in 2004. The aim of this study was to assess the reliability, validity and psychometric properties of the Korean-version of the SOAQ (K-SOAQ). Methods : Two hundreds twenty eight under-graduate college students were enrolled in this study. They were assessed with K-SOAQ, Obsessive-Compulsive Inventory-Revised (OCI-R), Beck Depression Inventory (BDI) and Beck Anxiety Inventory (BAI). Statistical analysis was done using calculation of Cronbach’s alpha, Spearman Correlation Coefficient and Principal Components Analysis. Results : There were no significant differences in sex, education, and total scores of BDI and BAI. The Cronbach’s alpha coefficient of K-SOAQ was high, Cronbach’s α=0.96. There was strong evidence for a one-factor solution, accounting for 60.3% of the variance. Convergent validity was examined through correlations between the SOAQ and the OCI-R (r=0.61). Divergent validity was examined through correlations between the SOAQ and two self report measures; BDI (r=0.12) and BAI (r=0.19). Conclusion : The K-SOAQ showed good reliability and validity for the assessment of severity of compulsive characteristics regarding symmetry, ordering and arranging. The K-SOAQ is a useful instrument for assessing compulsive symptoms related with symmetry, ordering and arranging in Korea.

국소 광적응 기능을 가지는 윤곽검출용 32×32 방사형 CMOS 시각칩의 설계 및 제조

박대식,박종호,김경문,이수경,김현수,김정환,이민호,신장규 한국센서학회 2002 센서학회지 Vol.11 No.2

국소 광적응 기능을 가지는 윤곽검출용 시각칩을 픽셀수 32x32의 방사형 구조로 CMOS 공정기술을 이용하여 설계 및 제조하였다. 생체의 망막은 넓은 범위의 입력 광강도에 대해서 물체의 윤곽을 검출할 수 있다. 본 연구에서는 시세포, 수평세포, 쌍극세포로 이루어진 망막의 윤곽검출 기능을 모델링하여 윤곽검출용 인공시각칩을 설계하였다. 국소 광적응을 위해, 입력 광강도에 따라 수용야의 크기를 국소적으로 바뀌게 하였다. 아울러 단위셀을 방사형으로 배치함으로써 영상데이터의 양을 감소시킴과 동시에 칩의 중심부분으로 갈수록 해상도가 높아지도록 설계하였다. 설계된 칩은 0.6 ㎛ double-poly triple-metal 표준 CMOS 공정기술을 이용하여 제조되었으며. HSPICE 시뮬레이션으로 성능을 최적화 시켰다. A 32x32 pixels foveated (linear-polar) stucture retina chip with the function of local-light adaptation for edge detection has been designed and fabricated using CMOS technology. Human retina can detect a wide range of light intensity. In this study, we use the biologically-inspired visual signal processing mechanism that consists of photoreceptors, horizontal cells, and bipolar cells in order to implement the function of edge detection in the retina chip. For a local-light adaptive function, the size of receptive field is changed locally according to the input light intensity. The spatial distribution of sensing pixels in the foveated retina chip has the advantages of selective reduction of image data and good resolution in central part to carry out the elaborate image processing with still enough resolution in the outer parts. The designed chip has been fabricated using standard 0.6 ㎛ double-poly triple-metal CMOS technology and optimized using HSPICE simulator.