가성 장폐쇄로 발현한 부신경절종 1 예

김용태,이기업,박건춘,송영기,이문호,유은실,이준호,진태선 대한내과학회 1991 대한내과학회지 Vol.40 No.5

Phenochromocytoma is a catecholamine-secreting tumor, most of which grow at the adrenal gland. About 109p Of pheochromocytomas are detected at the extra-adrenal chromaffine tissues and are called paraganglioma. The main symptoms of pheochromacytoma include hypertension, headache, palpitation, and sweating. Gastrointestinal symptoms such as abdominal pain, constipation, and vomiting are found in 20∼40% of patients with pheochromocytoma, but these are usually overlooked because of the severe, prominant cardiovascular symptoms. Intestinal pseudo-obstruction without hypertension in pheochromocytoma is very rarely found. It is caused by the decreased motility of the intestine and the over-contraction of the intestinal sphincter, which are caused by the unbalanced activation of α-and β-adrenal receptors. It can be hypothesized that catecholamine receptors in the cardiovascular system are down-regulated or desensitized, but those in the intestine remain intact. We report herein a case of pheochromocytoma in which intestinal pseudo-obstruction was the main presenting clinical manifestation. Symptoms of intestinal pseudo-obstruction were completely relieved by administration of phenoxybenzamine, an α-receptor blocker, and excisional surgery.

당뇨병유발백서에서 급성패혈증 병발시 적혈구막지질과산화의 변화

박성우,홍성관,유형준,장대영,강승식,유재명,임성희,최문기,노정우,이규만 대한당뇨병학회 1994 Diabetes and Metabolism Journal Vol.18 No.3

반용융 성형된 A357 합금 성형품의 부식 및 기계적 특성에 관한 연구

김상식,이명호,이정환,유영빈,이재식,이한중 대한금속재료학회(대한금속학회) 2001 대한금속·재료학회지 Vol.39 No.8

The mechanical and corrosion properties of thixoformed A357 alloys were examined with different reheating temperatures, and the results were compared with those of permanent mold cast A357 alloys. It was found that the thixoforming process significantly improved the mechanical properties (i.e., tensile elongation, impact energy and resistance to fatigue crack propagation) and the corrosion resistance of A357 alloys. A 380% increase in tensile elongation and a 120% increase in impact energy were, for example, observed with thixoforming process of A357 alloy in the as-fabricated condition, as compared to the PMC counterparts. The impact energy was extremely sensitive to reheating temperature due to the coarsening of eutectic Si particles. The resistance to fatigue crack propagation for the thixoformed alloy was also much higher than that of permanent mold cast counterpart in the as-fabricated condition. The resistance to both general corrosion and stress corrosion cracking was also greatly improved with thixoforming process. The present observations strongly suggest that the enhancement with thixoforming A357 alloy is largely associated with the size and shape of eutectic Si particles.

고 규소강에서 규칙상 소멸조건에 관한 연구

이택동,유지형,신제식,배준수,이진형,이혁모 대한금속재료학회(대한금속학회) 2001 대한금속·재료학회지 Vol.39 No.4

The ordered phase was tried to disappear in 6.5% Si steel to reduce the power loss and enhance the economic interests. They were prepared by the conventional casting or spray forming method, and they were investigated using the transmission electron microscopy(TEM). The variation in the methods of preparing the specimen did not result in any difference in suppressing the ordered B2 phase in the Fe-Si binary system. It was almost impossible to suppress this ordered phase keeping the silicon level as high as 6.5% even after the heat treatment at 1000℃ for 24 hr or after hot rolling. It was necessary to change the silicon level and control the cooling rate to prevent the ordering reaction, especially, in cooling after heat treatments. The silicon level of 5.8% was obtained as a maximum desirable value.

기계적 합금법으로 제조된 Al-Nb 합금 및 Al-Al3Nb 복합재료 압출재의 인장 특성

김상식,박민우,정광철,안인섭,류영빈,이광민 대한금속재료학회(대한금속학회) 1999 대한금속·재료학회지 Vol.37 No.12

Tensile behavior of mechanically alloyed(MA) Al-5 wt.%Nb alloy extrusion was examined at various temperatures and strain rates. The tensile ductility of MA Al-5wt.%Nb alloy extrusion was greatly reduced with increasing temperature and/or decreasing strain rate. The SEM observations of side and fracture surfaces of tensile fractured specimens demonstrated that the overall void density formed during deformation was considerably reduced, along with the sign of decreased plasticity around the dimples on the fracture surface. To understand the effect of grain size on the deformation behavior of submicron grain sized alloys, Al-5 vol. %Al₃Nb composite extrusions with different grain sizes were fabricated and tensile tested at different temperatures. The present study confirms that the reduction in tensile ductility of submicron grain sized alloys at elevated temperatures are undoubtedly related to the grain size. Fast dynamic recovery rates, due to the lack of dislocation substructures, in submicron grain sized alloys appears to be responsible for the elevated temperature reduction in tensile ductility.

가스 침질탄화처리한 SM35C 강의 기계적 성질에 미치는 고주파�칭의 영향

김학신,이규복,유정희,김형태,장환용 한국열처리공학회 2000 熱處理工學會誌 Vol.13 No.4

Carbon steel(SM35C) was gas nitrocarburized at 580℃ in 55%N₂-40%NH₃-5%CO₂mixed gas atmosphere, and then the steel was induction hardened at 850℃. The microstructure of gas nitrocarburized surface layer was observed by optical microscope and SEM. The phase analysis was carried out by X-ray diffraction method. The mechanical properties of gas nitrocarburized SM35C steel was evaluated by hardness, wear and fatigue test. The thickness of compound and diffusion layer were increased with increasing the gas nitrocarburizing time and the densest compound layer was obtained at 3hours gas nitrocarburizing time. In case of 15sec induction hardening after gas nitrocarburizing, the surface hardness was decreased from 800Hv to 630Hv owing to the decomposition of compound layer, but wear resistance was increased because of increased hardness of diffusion layer. The fatigue strength of induction hardened steel after gas nitrocarburizing, 58㎏f/㎟, was higher than 41.5㎏/㎟ of gas nitrocarburized steel and 45㎏/㎟ of induction hardened steel, respectively.

컴퓨터교육에서 정보교육으로의 전환을 위한 교육과정 모형 개발

김현철,이현옥,정순영,유헌창,이원규 한국컴퓨터교육학회 1999 컴퓨터교육학회 논문지 Vol.2 No.4

이 논문에서는 컴퓨터 교육이 정보 능력을 갖춘 인간을 육성한다는 교육 목표를 강조하기 위해 정보 교육 측면에서의 교육과정을 제안한다. 정보 교육이란, 정보활용능력과 정보처리능력을 배양하여 문제를 스스로 해결하고 정보화 사회에 적응할 수 있는 인재를 양성하는 것이다. 정보화 시대에 살아가기 위해서 정보 교육은 중요하다. 하지만 현재 우리 나라 정보 교육의 실태를 분석해 보면 많은 문제점을 발견할 수 있다. 가장 큰 문제점은 정보 교육을 위한 체계적인 교육과정이 미흡하다는 것이다. 이 때문에 학교급별 컴퓨터 교육의 목표와 내용이 연계가 이루어지지 못하고 교육혜택의 불평등이 나타나고 있다. 따라서 이 연구에서는 제 6차·7차 교육과정의 문제점을 분석하고 해결 방안으로 정보의식과 정보활용능력을 포괄하는 새로운 정보 교육과정 모형을 제안한다.

변단면(變斷面) Beam-Column 에 대한 축하중(軸荷重)과 Moment 의 상관관계

유철수,전홍건 고려대학교 공학기술연구소 1985 고려대학교 생산기술연구소 생기연논문집 Vol.21 No.1

The analytical method finding interaction relationship among axial load, moment, and slenderness for tapered beam-column is quite complicated. Moreover, analysis for some shapes of cross-section is impossible. Newmark's integration method can be used as numerical analysis which is applicable for any shape factors. Using Newmark's method Interaction relationships between axial load and moment for simply supported case were obtained and represented by figures.

수원지방에서 발생하는 모기(모기과 ; 파리목)의 계절적 소장과 유충서식처 조사에 관한 연구

유효석,양경형 고려대학교 한국곤충연구소 1992 昆蟲硏究誌 Vol.18 No.1

수원지방에서 발생하는 모기(모기과 ; 파리목)의 계절적 소장과 유충서식처 조사에 관한 연구. 양경형, 유효석(서울대학교 농업생명과학대학 농생물학과) 昆蟲硏究誌. 18: 15~ 24, 1992. 수원 지방에서 발생하는 모기의 종류와 그들의 계절적 발생소장을 조사하기 위하여 수원 시내 목장과 시외곽 아파트 지역에서 유문등 채집과 유충 채집을 실시하였다. 유문등 채집에서 전체 채집된 총6종의 모기중 금빛숲모기 (Aedes vexans)와 줄다리 집모기(Culex vagans)는 조기에 출현하는 종으로 5월에 발생하여 6월 4째주와 5째주에 최고의 밀도를 보였다. 가장 우점으로 나타난 종은 빨간집모기 (Cx. pipiens pallens)로 목장과 아파트 지역에서 주당 평균 각각 67.7과 33.5 개체를 채집하였으며, 아파트지역에서는 7월 2째주 목장에서는 8월 4째주에 최고치를 나타내었다. 한편, 중국얼룩날개모기 (An.sinensis)는 7월초에 최초 출현하였다가 8월에 그 밀도가 상승하는데, 8월 2째주에서 4째주까지 최고의 밀도를 보이며, 목장과 아파트 지역에서 주당 평균 21.8과 5.0 개체를 각각 채집하였다. 또한 작은 빨간집모기 (Cx. tritaeniorhynchus)는 늦게 출현하는 종으로 8월 중순에 최초 출현하였다가 9월 중순까지 밀도가 약간 상승하는 것으로 나타났다. 유충 서식처별 밀도조사에서는 서로 다른 6개의 서식처가 선정되었는데, 그 중에서 수답식 논이 가장 중요한 발생원으로 빨간집모기(Cx. pipiens)유충의 87.7%, 중국얼룩날개모기 (An. sinensis)유충의 95.4%가 논에서 서식하고 있었다. 반면 조기출현종인 줄다리모기 (Cx. vagans)의 경우에는 관개수로에서 77.1%로 가장 높은 유충 서식을 보였다. Light trap studies and mosquito larval samplings were undertaken to investigate the seasonal abundance and breeding habitats of mosquitoes in animal farm and apartment residential areas in Suwon fron May through September in 1990. Of a total of 6 species collected, the earlier appearance was Aedes vexans and Culex vagans in May and peaked in 4th 5th week in June. The most predominant species was Culex pipiens pallens with an average per night trap of 67.7 and 33.5 individuals in animal farm and apartment areas respectively; the higher peaks were marked during 2nd week of July in apartment area, 5th week in animal farm. Anopheles sinensis was appeared in early July and adult density increased through August, and then, the highest peak occurred in 2nd 4th week in August with an average of 21.8 and 5.0individuals in animal farm and apartment area respectively. Cx. tritaeniorhynrchus appeared later in the season in apartment area, marking in mid-August with an average of 1.5 individuals, the density increased to 6.5 individuals in mid-September showing the peak during the study period. Among 6 different mosquite larval breeding habitats investigated, the main breeding source of Anopheles sinensis and Cx. pipiens was from rice paddies near and around apatment as 95.4% and 87.7% of the total mosquito larvae were sampled respectively; however, Cx. vagans bred predominantly in irrigation ditches as 77.1% of the total larvae were sampled during the survey period.

Cu/Cr/polyimide 계의 계면파괴에너지

유진,박영배,박익성 대한금속재료학회(대한금속학회) 1999 대한금속·재료학회지 Vol.37 No.2

The interfacial fracture energies, Γ, of the Cu/Cr/polyimide system were deduced using X-ray measurement method and theoretical method with variation of Cu film thickness and pretreatment conditions on polyimide surface. The two methods showed reasonably good agreement for most cases, imparting validity of both approaches. Estimated Γ were quite independent of the metal film thickness and increased with the rf plasma power density of polyimide pretreatment as expected. Estimated values of Γ were 46.8±7.8. 170.3±42.9 and 253.9±44.4 J/㎡ for the rf plasma power density of 0.03. 0.036 and 0.05 W/㎠, respectively.