유체에 잠긴 다공 직사각평판의 고유진동 해석

유계형,권대규,정경훈,이성철 한국산업안전학회 2003 한국안전학회지 Vol.18 No.1

This paper presented an experimental modal analysis of clamped perforated rectangular plates submerged in water. The penetration of holes in the plates had a triangular pattern with P/D(pitch to diameter) 1.750, 2.125, 2.500, 3.000 and 3.750. The natural frequencies of the perforated plates in air were obtained by the Rayleigh-Ritz method and compared with the experimental results. Good agreement was obtained between the analytical solution and experimental result. The experimental results in water showed that the mode shapes are not sensitive to the depth of submergence. The natural frequencies were shown to decrease drastically once the perforated plates come in contact with water. However, the natural frequencies decrease with the depth of submergence until a certain depth is reached, and become the asymptotic values beyond this depth of submergence. The depth of submergence did not affect the damping ratio greatly.

대구치 직립 스프링 적용시 반작용에 관한 삼차원 유한요소법적 연구

최유경,김태우,서정훈 대한치과교정학회 1998 대한치과교정학회지 Vol.28 No.1

하악 제1대구치가 상실되고 하악 2대구치가 근심으로 경사된 겨우 이를 직립시키기 위하여 직립 스프링을 사용하였을때 초기에 나타나는 응력 분포와 치아의 변위 양상을 살펴보고 여러 조건하에서의 변화를 비교, 분석하여 바람직하지 못한 치아 이동을 감소시키기 위한 방안을 모색하고자 본 연구를 시행하였다. 3차원 유한요소법을 이용하여 하악치아, 치근막과 치조골의 형태와 물리적 특성을 컴퓨터로 재현시키고 브라켓을 모형화하여 치아에 부작한 후 helical spring, root spring, T-loop, box loop등 5가지 형태의 스프링을 beam요소로 모형화하여 적용시켜 유한요소 모델을 제작하였다. 스프링의 형태, cinch-back여부, activation 양, tip-back bend의 크기에 따른 차이를 보기 위하여 여러 조건하에서 탄선 적용시 나타나는 힘과 모멘트, 치아이동 변위를 개개치아의 FA point에서 계측하여 비교, 분석한 결과 다음과 같은 결론을 얻었다. 1. Helical spring과 root spring적용시 하악 견치와 제1소구치의 압하가 일어났고, 하악 제2대구치의 원심이동과 정출, 원심회전이 일어났다. 2. T-loop, modified T-loop, box loop 적용시 하악 제2소구치의 압하와 원심이동이 일어났고, 하악 제2대구치의 직립에 필요한 원심이동과 원심회전은 T-loop에서 가장 크게 나타나고, box loop에서 가장 작게 나타났다. 3. T-loop에서 cinch-back을 한 경우 하악 제2대구치 치관의 원심이동과 원심회전은 약간 감소하였으나, 치아의 정출도 동시에 감소하였다. 4. T-loop에서 activation양을 증가시킴에 따라 하악 제2대소구치의 근심이동이 점차 증가하여 공간폐쇄 경향을 보였고, 치관의 원심회전 역시 점차 증가하였으나, 하악 제2소구치의 원심 이동도 약간 증가하였다. 5. T-loop에서 tip-back bend의 양을 증가시킴에 따라 하악 제2대구치의 직립에 필요한 원심이동과 원심회전이 점차 증가하였으나, 치아의 정출은 더욱 급격히 증가하였다. The purpose of this study was to investigate the stress distribution and tooth displacement at the initial phase produced by 5 type of molar uprighting springs using finite element method. The three dimensional finite element model of lower dentition, bone and springs was composed of 5803 elements and 2071 nodes. The results were as follows: 1. In case of helical spring and root spring, intrusion of lower canine and first premolar were observed and distal tipping, translation and extrusion of lower second molar were observed. 2. In case of T-loop, modified T-loop and box loop, intrusion and distal translation of lower second premolar were observed, and the largest crown distal tipping and translation of lower second molar were observed in T-loop and the smallest were observed in box loop. 3. In case of T-loop with cinch-back, crown distal tipping and translation of lower second molar were decreased, but extrusion was also decreased. 4. With increase of activation in T-loop, mesial translation and crown distal tipping of lower second molar were increased and edentulous space was closing, but distal translation of second premolar was also increased. 5. With increase of tip-back bend in T-loop, distal tipping and translation of lower second molar were increased, but extrusion was also increased more largely.

화농성 슬관절염이 동반된 수막구균성 수막염 1예

김태연,유진홍,박성환,김연식,임상현,신완식,강문원,정창훈,최문구,강지민 대한화학요법학회 1997 대한화학요법학회지 Vol.15 No.2

저자들은 최근 화농성 슬관절염과 병발한 수막구균성 수막염 1예를 체험하였고, 이는 국내에서 아직 보고되지 않은 드문 예로 사료되어 문헌고찰과 함께 보고하는 바이다. We recently experienced a case of meningococcal meningitis associated with pyogenic arthritis in a 37-year old male patient. Pyogenic arthritis developed in right knee joint during treatment for meningococcal meningitis. He was treated successfully by appropriate antibiotics and arthroscopic irrigation. To our knowledge, such a rare case has not ever been reported in Korea, Hence we report this case with a review of related literatures.

정신분열증 환자군에서 낮병원 치료가 경각심과 정신운동기능에 미치는 영향에 대한 예비 연구

오태성,김도훈,오병훈,현명호,유계준 大韓神經精神醫學會 1996 신경정신의학 Vol.35 No.6

Objectives : The aim of study is to compare the neuropsychological function changes between day hospital schizophrenic patients and out patient schizophrenic patients and to examine the effect of day hospital program on the cognitive function of schizophrenics. Methods : Neuropsychological test was done two times at discharge and 2 months later in 11 day hospital schizophrenic patients and 10 out patient schizophrenic patients by DSM-Ⅳ criteria. Vigilance, motor performance series are used as a computerized neuropsychological batteries. Results : Day hospital patients have significantly increased performance in some of motor performance series test items, but sustained attention have no tendency for increasing in day hospital patients. Conclusion : This results are preliminary. But this study suggest that psychomotor function of schizophrenics can be changed following day hospital treatment. And also we suggest that further day hospital treatment program expecially including congnitive rehabilitation needed.

선형유도전자펌프내의 자기유체 유동에 관한 수치적 연구

최훈기,유근종,박태봉,은재정,장남영 국립7개대학공동논문집간행위원회 2003 공업기술연구 Vol.3 No.-

Numerical analysis is performed for magnetic and MHD flow fields in Electro-Magnetic(EM) pump. A finite volume method is applied to solve magnetic field governing equations and the Navier-Stokes equations. Vector and scalar potential methods are adopted to obtain the electric and magnetic fields and the resulting Lorentz force in solving Maxwell equations. The magnetic field and velocity distributions are found to be influenced by the magnitude of the Reynolds number and the phase of applied electric current. Computational results indicate that the magnetic flux distribution with changing phase of electric current is characterized by a pair of counter-rotating closed loops. The velocity distribution of the flow field is influenced on the intensity of Lorentz force.

코쉬섬 1차 반복 형태의 마이크로스트립 패치 안테나에 관한 연구

김일권,유태훈,육종관,박한규 연세대학교 전파통신연구소 2001 電波通信論文誌 Vol.5 No.1

In this paper, the microstrip patch antenna applying the koch island fractal geometry is introduced in order to reduce the antenna patch size. By space-filling property of fractal geometry, the microstrip patch applying koch island has low frequency compared with square patch antenna. In the case of 1st order iteration patchs are investigated by simulator and experiment. Through this, it is found that as the fractal iteration factor increase, the resonant frequency of koch island patch is lower. therefore koch island patch antenna can reduce patch size compared with square patch antenna. and The fabricated patch antenna is matched by using quarter wave length impedance transformer and return loss and radiation patterns are measured. The measurement result shows that the copolarization pattern of koch patch is similar to that of square patch. The cross polarization power level is -15∼-20dB.

착향탄산음료를 마시고 발생한 아나필락시스 1예

이재천,이태훈,김윤이,유빈,문희범,조유숙 대한알레르기학회 2004 천식 및 알레르기 Vol.24 No.2

응급실을 내원한 65세 이상 노인 환자의 분석

김진년,김태훈,강양욱,오명,김상철,김성훈,권계형,남홍우,이홍순,유형준 대한노인병학회 2001 대한노인병학회지 Vol.5 No.3

알쯔하이머형 치매 환자에서 우울증의 유무에 따른 인지기능과 일상생활 수행능력의 차이

김승민,최태규,안석균,손석한,유계준,오병훈,오희철 大韓神經精神醫學會 1999 신경정신의학 Vol.38 No.2

연구목적 : 알쯔하이머형 치매 환자에게 있어서 중요한 행동증상중의 한가지인 우울증의 다양한 범위로 보고되고 있으며 우울증과 인지능력 및 기능적 능력과의 관계에 대한 연구가 매우 중요하게 부각되고 있다. 본 연구의 목적은 지역사회에 거주하는 경도 및 중등도의 알쯔하이머형 치매 환자를 대상으로 우울증이 일상생활 수행능력과 인지기능의 특정 영역과 연관이 있는지의 여부를 알아보기 위함이다. 방 법 : 본 연구대상은 경기도 광주군에 거주하는 65세 이상의 알쯔하이머형 치매 노인 48명이며, 한국판 Mini-Mental State Examination(이하 MMSE-K), 한국어판 신경행동학적 인지상태 검사(이하 한국어판 NCSE), 한국형 노인우울검사(이하 KGDS), 기본적인 일상생활 수행정도(이하 ADL), 그리고 도구적인 일상생활 수행정도(이하 IADL)를 연구도구로 하여 이들로부터 자료를 수집 조사하였다. 연구대상은 KGDS에 의해 우울 치매군과 비우울치매군으로 분류하였으며 두 군간의 상기 척도에 의해서 얻어진 결과를 χ²test 및 independent t-test를 이용하여 분석하였다. 결 과 : 우울 치매군과 비우울 치매군은 성별, 연령, 교육수준 및 MMSE-K 점수의 유의한 차이가 없었다. 우울 치매군은 비우울 치매군보다 ADL의 한 항목인 목욕하기에서 유의한 저하를 보였다. 우울 치매군은 비우울 치매군보다 IADL의 총점 및 식품점에 가서 장보기, 집안일(청소나 정리정돈), 금전 관리의 3개 항목에서 유의한 저하를 보였다. 그러나 우울 치매군은 비우울 치매군은 한국어판 NCSE를 이용한 인지기능의 영역별 비교에서는 유의한 차이를 보이지 않았다. 결 론 : 이상의 결과로 미루어 볼 때 알쯔하이머형 치매 환자에서의 우울증은 기본적인 일상생활 기능의 일부와 도구적인 일상생활 기능의 저하와 상당한 관련 있고, 이러한 우울증에 동반된 일상생활 기능의 저하는 인지기능의 영향에 기인하지 않는 것임을 시사된다. Objectives : Coexistence of depression is one of the important behavioral symptoms in patients with dementia of Alzheimer type. The study on the relationship between depression and cognitive abilities and /or functional abilities emerges as very important one. The aim of this study was to investigate whether depression is related to the impairment of daily activities and to certain areas of cognitive function in mild to moderate dementia of Alzheimer type. Methods : In this study, 48 patients with dementia of Alzheimer type among elderly community-residents in Kwangju, Kyunggi province, age 65 and older, were finally included. We examined their demographics and administered Korean Version of the Mini-Mental State Examination(MMSE-K). Korean Version of the Neurobehavioral Cognitive Status Examination (Korean version of NCSE), Korean Form of Geriatric Depression Scale(KGDS), Activities of Daily Living(ADL), and Instrumental Activities of Daily Living(IADL) to the subjects. We classified the subjects into two groups, dementia with and without depression on the basis of KGDS scores. The two groups were compared using χ²test and independent t-test. Results : The results show that the two groups did not differ in sex, age, education, and scores of MMSE-K. The depressed dementia group showed significantly poorer performance in bathing, one item of ADL, than the non-depressed dementia group. The depressed dementia group showed significantly more impairment in total scores of IADL and each score of three item(shopping, housework, handling finances) than the non-depressed dementia group. However, the two groups showed no significant difference in five major cognitive ability areas of Korean version of NCSE. Conclusion : These results suggest that depression in patients with dementia of Alzheimer type is highly related to the functional impairments, instrumental activities of daily living and part of activities of daily living, beyond the effects of cognitive impairments.

신고리 지역 기상관측을 통한 계절별 대기안정도 특성분석

송상근,김유근,오인보,정주희,조윤미,우경은,강태훈 부산대학교 환경문제연구소 2003 環境硏究報 Vol.21 No.-

In this study, we analyzed the characteristics of atmospheric stability to investigate local environment change at an atomic power plant in Gori region. The used data was obtained from field observation of major meteorological variables such as wind direction and speed, air temperature, relative humidity, and solar radiation using AWS (Automatic Weather System) in Gori region from February to September in 2003. As a result, when strong northerly winds (more than 4~6 m/s) and weak northwesterly winds (2~3m/s) blow, atmospheric stability was neutral and stable from winter to spring, respectively. Atmospheric stability (neutral) in summer was similar to that in two other seasons (winter and spring), but it was stable for weak southwesterly winds (2~3 m/s). Finally, atmospheric stability was neutral for strong winds (over 4~6 m/s) in fall without respect to wind direction, while that was stable for very weak winds (less than 2 m/s).