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.

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.

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.

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.

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.

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

자동차 엔진오일 열화상태 in situ 측정용 전기용량 센서

이래덕,김한준,세메노프 한국센서학회 2001 센서학회지 Vol.10 No.4

A coil-type capacitive sensor on which the deterioration of the car engine oil can be in situ measured, has been developed. The sensor was designed to get over 10 pF at the limited space on the drain hole of the oil pan. The design factors for stable capacitance measurement such as coil diameter and winding condition, materials and configuration of the coil former, and shielding method, etc., were known by both computer simulation and experimental investigations. The dielectric properties measured by several sensors for an used sample oil were consisted within 0.25 %. The sensor installed on the cat having severe vibration, temperature and humidity fluctuation, even electromagnetic noise, has shown very distinguishable results.

보의 곡율(曲率)과 처짐에 대한 탄성론적(彈性論的)인 해석

이창수,유철수 고려대학교 공학기술연구소 1978 고려대학교 생산기술연구소 연구보고 Vol.9 No.1

Att exact solution for curvature and displacement of infinitely long isotropic beam under a concentrated load are formulated. This solution satisfies the equilibrium and compatibility equations. Local effect is defined as the quantity obtained by subtracting the solutions of elementary Bernoulli-Euler's simple beam theory from the exact solutions developed in this thesis. An Airy stress function is introduced to solve the Boussinesq-Flamant problem related to an isotropic half plane under a concentrated load. The formal solutions are expressed in terms of Fourier integral and these integrals evaluated numerically using Simpson`s one-third rule by computer. The numerical results for the curvature are obtained and the numerical results indicate that the local effect of the concentrated load on the curvature decreases rapidly with increase of distance from the point of application of the load, At cross sections at a distance greater than the beam depth the local effect on the curvature is practically zero.

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.

Isolation and Transcriptional Expression of CuZn Superoxide Dismutase from Codonopsis lanceolata

Lee,Kang,In,Jun-Gyo,Yu,Chang-Yeon,Yun,Song-Joong,Min,Byung-Hoon,Rho,Yeong-Deok,Kim,Moo-Sung,Yang,Deok-Chun 한국자원식물학회 2004 Plant Resources Vol.7 No.3

To investigate the defense mechanism against the abiotic stress, a cDNA clone encoding a CuZn superoxide dismutase (CuZnSOD) protein was isolated from a cDNA library prepared from tabroot mRNAs of Codonopsis lanceolata. The eDNA, designated ClSODCc, is 799 nucleotides long and has an open reading frame of 459 bp with a deduced amino acid sequence of 152 residues. The deduced amino acid sequence of ClSODCc matched to the previously reported CuZnSODs. Consensus amino acid residues (His-45, -47, -62, -70, -79, -119 and Asp-82) were involved in Cu-, Cu/Zn-, and Zn- binding ligands. The deduced amino acid sequence of ClSODCc showed high homologies (82%-86%) regardless of species. Expression of ClSODCc by oxidative stress was increased up to 1 h after treatment and declined gradually. Much earlier and stronger expression of ClSODCc was observed in the cold stress treatment.