FEM을 이용한 선삭가공 절삭조건의 영향 분석

임세환,송춘삼,홍석관,강정진,김주현 한국공작기계학회 2007 한국공작기계학회 추계학술대회논문집 Vol.2007 No.-

A plane strain finite element model is developed to simulate turning with continuous chip formation using adaptive remeshing during the thermal-mechanical coupled analysis. Comparisons between the experimental and simulation results for cutting forces are performed to validate FE analysis results. Influences of machining parameters such as depth of cut, cutting speed and feed rate on cuting force and shear angle are analyzed by Taguchi method. The more depth of cut and feed rate result in the increase of cutting forces, but the rates of increase are decrease due to the larger shear angle. As the cutting speed increases, von Mises stress of workpiece near the tool tip decreases because the strength of specimen decreases at high temperature above 500℃. This thermal effect on cutting force is negligible because the affected area is very localized and the average values of von Mises stress in the shear plane are the same among the diverse cutting parameters.

Si₃N₄/SiC 복합체의 기계적 성질에 미치는 Y₂O₃-Al₂O₃계 소결조제의 영향

이홍림,서유석,이형직 연세대학교 산업기술연구소 1992 논문집 Vol.24 No.2

Si₃N₄/SiC composites were prepared by mixing Si₃N₄powder with SiC powders of 0, 10, 20, 30 vol%. To these composites were added the powders of Y₂O₃-Al₂O₃system as sintering aids. These samples were hot-pressed at 1850℃ for 60min under a pressure of 30 MPa in N₂. Some of the samples were annealed at 1400℃ for 4 hr under N₂ before the measurement of mechanical properties. β-Si₃N₄ phase is starting powder was all transformed to β-Sic phase remained unchanged. The fracture toughness of the composites increased more or less with the increase of SiC content. The room temperature strength decrease was observed around 10-30 vol% of SiC content. For the sample in which grain boundary crystallization occurred after annealing, fracture toughness increased while roon-temperature strength decreased.

서울의 Penicillinase Producing Neisseria gonorrhoeae 발생빈도(1997)

김재홍,문득곤,김정수,김용준,임동진,박상훈,김희성,이민수,송기훈,김갑형,김형석,성소영,이인섭,김석우,황지환,조창근,김경문,부태성 대한화학요법학회 2000 대한화학요법학회지 Vol.18 No.3

Background : In recent years, gonorrhea has been pandemic and remains one of the most common STDs in the world, especially in developing countries. Objective & Methods : For the detection of a more effective therapeutic regimen and assessing the prevalence of PPNG, we have been trying to study the patients who have visited the Venereal Disease Clinic of Choong-Ku Public Health Center in Seoul since 1980 by means of the chromogenic cephalosporin method. Results : In 1997. 99 strains of N. gonorrhoeae were isolated, among which 45(45.5%) were PPNG. Conclusion : The prevalence of PPNG in Seoul, which had been decreased to 39% in 1996 after a peak of 74.3% in 1993, is increased to 45.5% in 1997.

양측 쇄골하동맥 및 양측 신동맥 협착을 동반한 Takayasu 동맥염 1예

임선호,임수빈,오석규,이재홍,정진원,박양규,박옥규,소병준,노병석 대한순환기학회 1997 Korean Circulation Journal Vol.27 No.8

단기교육으로 시행가능한 심실기능평가법

김원,임경수,오병연,홍은석,김영식,김선만,이부수,현석천,김영득 대한응급의학회 2000 대한응급의학회지 Vol.11 No.4

Background: The initial history, physical examination, and ECG assessment should focus on identification of potentially serious noncardiac or cardiac disorders, including coronary artery disease, congestive heart failure, and electrical instability at the emergency room. additionally, it is essential to define disease severity, stability and need for emergency therapy. echocardiography is a useful tool for this purpose. especially Doppler echocardiography may be more sensitive and time-saving diagnostic tool for the evaluation of patients presenting with cardiogenic symptoms. So we evaluate the feasibility of the echocardiographic measurement by emergency physicain after short-term course. Method and Results: Twenty volunteers(10 male, 38.8±9.3 years) were included in the study for measurement of myocardial performance index and established parameters of ventricular function using conventional echo-Doppler methods. Myocardial performance index: (ICT+IRT)/ET, was obtained by subtracting ejection time(ET) from the interval between cessation and onset of the mitral inflow velocity to give the sum of isovolumic contraction time(ICT) and isovolumic relaxation time(IRT). The most of mean values of echocardiogrphic parameters were not significantly different between those of cardiologist and those of emergency physicians(p<0.01). The duration for measuring myocardial performance index was shortest among echocardiographic parameters. the validity of echocardiographic parameters measured by emergency physicians was proved relatively good. Conclusion: It is proved to be feasible for emergency physician to perform echocardiographic evaluation of ventricular function after short-term course

도시지역에서 선행강우지수를 고려한 저수유출 시뮬레이션 모형

허창환,임기석,송시훈,지홍기 대한상하수도학회 2003 상하수도학회지 Vol.17 No.1

This study is aimed at the development of a deterministic runoff model which can be used for low flow runoff. The model is formulated by the watershed runoff model. Based on the assumptions that runoff system is nonlinear, the proposed watershed runoff models are the conceptual model and artificial neural network model. In the model structures, the conceptual model divide the runoff system into a surface structure and a subsurface structure corresponding to the surface flow, and inter flow and ground water flow. The lag time effect of surface can be represented by the sub-tank of surface structure in the conceptual model. Fifteen neural networks models using Quasi-Newton technique were prepared to find the optimum parameters with each of them having different numbers of hidden layers and hidden layers nodes. The parameter calibration of inter flow and ground water flow in the subsurface structure of the conceptual model is made by separating the components with numeric filter. The runoff coefficient (α_2, K_1) is expressed as the function of antecedent precipitation index (API) in the conceptual model. The parameters related to the surface flow can be calibrated with the runoff coefficient (α_1, α_11, C_1, C_2) in the conceptual model. In the conceptual and ann model an algorithm are developed to calibrate the parameters automatically based on efficiency criteria. The conceptual model shows more closely to the observed hydrograph than ann model.

渗出性 多型紅斑(Erythema Multiforme) 患者 1例에 대한 證例報告

류현신,임승환,정현아,홍석훈 대전대학교 한방병원 2002 惠和醫學 Vol.11 No.1

Introduction : Erythema multiforme is an inflammatory eruption specialized by target shape erythematous, edematous, blistered dermatitis. Objective : The purpose of this study was to estimate the efficacy of oriental medical treatment and management on erythema multiforme. Subjective : We studied about one patient who visited Daejeon University Oriental Hospital Dept. of Dermatology with exudative erythema multiforme. Method : We treated this disease with herb medicine and acupuncture. Results : This patient had high fever, chilling sense, itching sense, whole body pain and target shape erythema. We diagnosed him as an erythema multiforme. The cause of this disease is bi-seub-yeol and poong-yeol by oriental medical theory. We prescriped to him seon-bang-pae-dok-tang and bang-poong-tong-seong-san. After three days, he could get over these symptoms. Conclusion : Considering this above results, more oriental medical study is needed and oriental medical treatment on the erythema multiforme is very effective to treat this disease.

자연정화공법에 의한 인공습지 하수처리장에서 최적 수생식물의 선정

서동철,장병일,조인성,임석천,이홍재,조주식,김홍출,허종수 한국환경농학회 2006 한국환경농학회지 Vol.25 No.1

목련과 수종과 부위에 따른 견직물의 천연염색변이

박재인,연방희,최태호,이은경,임선희,김홍은,조남석,김태동 忠北大學校 農業科學硏究所 2003 農業科學硏究 Vol.20 No.-

In order to establish a dyeing method with Magnoliaceae tree species dyeing was examined with 4 different parts, leaf, stem bark, root, flower of 4 Magnohaceae species, Magnolia kobus Dc., Magnolia denudata Desr, Magnolia obovata Thunb, Liriodendron tulipifera L Mordants used were chemicals, AIK(SO_4)_2 24H_2O, Ca(OH)_2, FeSO_4 7H_2O. All four species showed similar coloring among four different parts. Leaves and petals showed dark yellow, stem bark, grayish yellow, root bark, dark red or yellow. Al mordant made more brighter colour than Fe mordant. Stem bark showed less difference in color by mordants, whereas petals did the biggest.

가토에서 일측 요관 부분 및 완전폐색시 신장과 요관의 조직학적 변화

김상현,김용웅,육승모,한동석,노안식,임재성,김홍식,나용길,설종구 충남대학교 의학연구소 2003 충남의대잡지 Vol.30 No.2

This study was designed to clarify histologic changes in the experimental rabbit kidney and ureter after unilateral partial or complete ureteral obstruction. A total of 20 adult white rabbits were divided into 4 subgroups in the partial obstruction followed by 2 weeks, the partial obstruction followed by 4 weeks, the complete obstruction followed by 2 weeks, and the complete obstruction followed by 4 weeks. The normal control group was consisted of 5 adult white rabbits. The kidneys and ureters for light microscopy were fixed in 10% neutral formalin, embedded in paraffin and stained with hematoxylin and eosin. Abnormal histologic fingings showed in ipsilateral kidney and ureter of all subgroups(such as dilatation of uriniferous tubule, focal necrosis and desquamation of epithelium, interstitial fibrosis, glomerular congestion, widening of Bowman's space, dilatation of ureter, epithelial cell atrophy or loss, interstitial fibrosis and interstitial inflammation). These findings were most severe in the group of the complete-obstructed ureter for 4 weeks. No significant changes showed in contralateral ureter of all subgroups. The degree of obstruction was severe and period of obstruction was long, the histological changes in ipsilateral side were severe. Despite of changes in ipsilateral side no abnormal findings showed in contralateral side. We suggest that long term experimental investigation of histologic changes in ipsilateral side and compensatory changes in contralateral side have to be studied.