유한요소법을 이용한 과도 선형 동탄성 해석

성기영,이성희,심우진 金烏工科大學校 2000 論文集 Vol.21 No.-

The Finite element methods have been applied to various problems of interest, as witnessed by the extensive literature currently available. Transient linear elasto-dynamic problems are solved in a time domain by the FEM, for which the finite element equations are derived from the weak formulation based on the differential equations of motion using a stable time integration scheme known as the Newmark method, where the dependent variables are semidiscretized in series of the products of the spatial and temporal functions. The wave propagation problems by two and three dimensional and axisymetric models are analyzed to show the versatility of the presented formulation, resulting in good and stable numerical results.

2000-2001년 서울 북부 지역 홍역 유행의 양상

심민주,정주영,김상우,한태희 인제대학교 백병원 2003 仁濟醫學 Vol.24 No.1

Purpose : To investigate the clinical features of measles outbreak, we studied epidemics of measles during 2000-2001 in northern Seoul district. Materials and Methods : Among 208 patients under 15 years of age who visitied or admitted to our hospital from April. 2000 to February, 2001, we selected 160 patients whose measles IgM antibody was positive. We investigated the age, clinical manifestation, vaccination history, measles IgG antibody. Results : Forty five percent of the patients were under 12 monthes of age, 30.6% were 12-48 months of age and the rest of the patients were over 48 months of age. This epidemic started in April, 2000 and the number of patients increased abruptly in November, reached to peak in December, after then decreased. Fever, cough, and rash were observed in all patients but rhinorrhea in 69%, conjunctivitis in 49%, and Koplik spot in 65.6%. Complication was noted in 74% of patients, and the most common complication was pneumonia(54.4%), followed by gastroenteritis(28%) and acute otitis media and bronchitis. 32.2% of patients had a history of more than one-dose vaccination, and two-dose of vaccination in 12% of patients. Positive rate of Measles IgG antibody was 92% in vaccinated group. Conclusion : Routine vaccination of single measles vaccine and enhancement of revaccination at ages of 4-6 years is necessary to prevent outbreaks when measles are prevalent. More studies are required to investigate the cause of high rate of primary vaccine failure.

植物景觀의 治癒 效果

沈愚京,鄭聖惠 高麗大學校 自然資源科學硏究所 1995 自然資源科學硏究 Vol.3 No.-

초음파 센서를 활용한 이륜차 사각지대경보시스템 연구

심정현,정희철,이상혁,김우진,이상욱 순천향대학교 산업기술연구소 2022 순천향 산업기술연구소논문집 Vol.28 No.2

The purpose of this paper is to prevent driver from accidents by effectively notifying the driver blind spot warning in a short distance such as a narrow alley when using a two-wheeled vehicle. It is easy to see that two-wheeled vehicles are more fatal in the event of an accident. We analyzed and researched a safety warning device in low-speed driving to identify critical factors for drivers in two-wheeled vehicle driving, and to identify areas that can be improved. Based on the analysis and research, an experiment was conducted and a warning system was applied to the manufactured motorcycle.

電子産業의 要求측면에서 본 工業高等學校 電子系列學科 敎育改善을 爲한 基礎硏究

羅聲雄,林在鳳,沈殷燮,金煥宇,權五錫 충남대학교 공업교육연구소 1982 論文集 Vol.5 No.1

This thesis aims at finding the present abilities of the graduates from Electronic Departments of Technical High schools, their present value to the Electronic Industry, and the required qualifications. The following suggestions are proposed to improve the education of Technical High schools, and to meet the needs of the future. -Such basic subjects as English, Korean(including Chinese letters), Mathematics are to be emphasized in the curricula. -Basic theory in major subjects should be broadened rather than stressing experiments and practice in specific trades. -Major subjects are to include more wide and general theories than those of the present.

Butadiene-Vinyl Chloride System의 共重合性에 關한 分子軌道論的 考察

金祐植,沈相喆,朴炳珏 慶北大學校 1973 論文集 Vol.17 No.-

The wave function coefficients and π-electron energies of butadiene (M_1), butadiene radical (∼M_1°), vinyl chloride (M_2), and vinyl chloride radical (∼M_2°) were calculated respectively by means of the simple Hu¨ckel method, and the second perturbation energies, the stabilization energies (ΔErs), in the transition states of the following reactions were also calculated. ∼M_1°+M_1 → ΔE_11∼M_1°, ∼M_1°+M_2 →ΔE_12 ∼M_2° ∼M_2°+M_2 → ΔE_22∼M_2°, ∼M_2°+M_1 →ΔE_21 ∼M_1° As the stabilization energy ratio, ΔE_11/ΔE_12 is 1.23 and ΔE_22/ΔE_21 is 0.73, the copolymer of butadiene-vinyl chloride system consists mostly of butadiene. This fact agrees qualitatively with reactivity ratio of these monomers. Therefore, the copolymerizability of this monomer system can be estimated as the stabilization energy ratio. The orientation of radical addition copolymerization of the butadiene-vinyl chloride system is discussed on the basis of the calculated frontier electron density.

구내 표준 방사선사진을 이용한 구내방사선촬영기의 선질 평가

이상섭,권혁락,심우현,오승현,이지연,전국진,김기덕,박창서 대한구강악안면방사선학회 2000 Imaging Science in Dentistry Vol.30 No.3

Purpose : This study was to evaluate the beam quality of intraoral X-ray equipments used at Yonsei University Dental Hospital (YUDH) using the half value layer (HVL) and the characteristic curve of intraoral standard X-ray film. Materials and Methods : The study was done using the intraoral X-ray equipments used at each clinical department at YUDH. Aluminum filter was used to determine the HVL. Intraoral standard film was used to get the characteristic curve of each intraoral X-ray equipment. Results : Most of the HVLs of intraoral X-ray equipments were higher than the least recommended thickness, but the REX 601 model used at the operative dentistry department and the X-707 model used at the pediatric dentistry department had HVLs lower than the recommended thickness. The slopes of the characteristic curves of films taken using the PANPAS 601 model and REX 601 model at operative dentistry department, the X-705 model of prosthodontic dentistry department, and the REX601 model at the student clinic were relatively low. Conclusion : HVL and the characteristic curve of X-ray film can be used to evaluate the beam quality of intraoral X-ray equipment. In order to get the best X-ray films with the least radiation exposure to patients and best diagnostic information in clinical dentistry, X-ray equipment should be managed in the planned and organized fashion. (Korean J Oral Maxillofac Radiol 2000; 30: 183-188)

기하학적 불연속이 동탄성 응력집중계수에 끼치는 영향

이성희,심우진 금오공과대학교 산업기술개발연구원 2001 産業技術開發硏究 Vol.17 No.-

In this paper, the dynamic stress concentrations are computed for two-dimensional specimens with geometric discontinuities using the time-domain Finite Element formulations which has been recently developed based on the governing equations in convolution integral. The effect of geometric discontinuities, such as the hole and notch, on the stress concentration is especially surveyed. Numerical solutions are compared with the ones by the general purpose engineering software NASTRAN and researchers, and it is shown that numerical results of good accuracy are obtained.

오스템퍼링한 구상흑연주철(ADI)의 드릴 가공시 경도 및 현미경조직변화에 관한 연구

조규재,장우양,심재기,홍성오,김선진 한국공작기계학회 1999 한국생산제조학회지 Vol.8 No.1

This paper was carried out to know the influence of advanced austempered ductile cast iron (ADI) on the tool life and mechanical properties of drilling machinability. For manufactured method of ADI, the spheroidal graphite cast iron were austenized at 900℃ for 1 hour and then austempered for 2 hour at 370℃ in the salt bath. And interrelationship has been investigated between tool life and mechanical characteristics of specimen material on drilling condition when the ordinary and step-feed drilling are carried out to drill holes of specimens. Tensile strength and hardness of ADI decrease and elongation of ADI increases with the increase austempered temperature. It is known that about 2 times of tool life in the case of step-feed decreases compared with ordinary feed due to the high hardness of ADI and hardness ascribed to the fact that retained austenite beame to martensite state due to cutting heat in drilling. Under the constant feed rate 0.1㎜/rev relation between hardness and length of end tip after drilling can be formularized to Hv=788.46L^-0.096 for the cutting speed 6.1m/min.

용매-물-1-프로판올계의 액-액 평형

박동원,정상훈,신현심,서진기,이진우 동아대학교 공과대학부설 생산기술연구소 1997 生産技術硏究所硏究論文集 Vol.2 No.1

Due to the rising cost of energy, new separation processes based on extraction are becoming more attractive than before. Thus, the need for calculating and predicting liquid-liquid equilibria(LLE) compositions has very much increased. The purpose of this study is to determine the binodal curves, tie lines, plait points and selectivity for the temary systems of 1-propanol-water with toluene, ethyl-acetate, 1-butanol, n-hexane and amyl alcohol as solvent and also for the quarternary solvent-NaCl salt solution-1-propanol systems at 25℃.