유압벌지실험을 이용한 순 티탄늄 판재의 소성유동곡선 평가(제2보)

김영석(Kim, Young-Suk),김진재(Kim, Jin-Jae) 한국산학기술학회 2016 한국산학기술학회논문지 Vol.17 No.4

본논문에서는대형 선박의 판형열교환기등에 널리 이용되고있는 순 티타늄판재의소성변형을 유한요소해석하기 위한 기초 데이터로서 순 티타늄 판재의 유동곡선을 평가하였다. 순 티타늄 판재의 프레스 가공 시에 판재에는 국부적으로 큰 소성변형이 발생하고 있다. 그러나 기존의 단축 인장실험에서 얻을 수 있는 소성변형률이 낮아서 티타늄 판재의 가공공정 설계를 위한 유한요소해석의 정밀도를 떨어뜨리는 경우가 있다. 본 연구에서는 큰 소성변형률 까지 안정적으로 성형이 가능한 유압벌지실험을 수행하여 재료의 소성변형에서 가공경화특성을 나타내는 유동곡선으로써 진응력-진변형률 선도를 구하였고 그 결과를 인장실험 결과와 비교하였다. 순 티타늄 판재의 유압벌지실험에서 재료의 변형률은 3D 디지털 영상 상관법을 이용한 ARAMIS 시스템으로 실시간 측정된다. 이 유압벌지실험으로부터는 소성 변형률이 0.65 이상 까지도 안정적으로 재료의 소성유동곡선을 얻을 수 있었으며 그 결과는 Kim-Tuan 이 문헌 17[Y.S. Kim, J.H. In, Korean Acadmia-Ind. Coop. Soc.,(be in print), 2016] 의 연구에서 제안한 가공경화식으로 잘 핏팅됨을 알 수 있었다. In this study, the plastic flow curve of commercially pure titanium sheet (CP Ti) actively used in the plate heat exchanger etc., was evaluated. The plastic flow curve known as hardening curve is a key factor needed in conducting finite element analyses (FEA) for the forming process of a sheet material. A hydraulic bulge test was performed on the CP Ti sheet and the strain in this test was measured using the DIC method and ARAMIS system. The measured true stress-true strain curve from the hydraulic bulge test (HBT) was compared with that from the tensile test. The measured true stress-true strain curve from the hydraulic bulge test showed stable plastic flow curve over the strain range of 0.7 which cannot be obtained in the case of the uniaxial tensile test. The measured true stress-true strain curve from the hydraulic bulge test can be fitted well by the hardening equation known as the Kim-Tuan model.

Immobilization with Ketamine HCI and Tiletamine-Zolazepam in Cynomolgus Monkeys

Myung-cheol Kim,Sung-hyeok Hong,Soo-jin Lee,Young-suk Kim,Jae-il Lee 대한수의학회 2003 Journal of Veterinary Science Vol.4 No.2

with Ketamine HCl and Tiletamine-Zolazepam in Cynomolgus MonkeysJae-il Lee, Sung-hyeok Hong, Soo-jin Lee, Young-suk Kim and Myung-cheol Kim*Laboratory of Veterinary Surgery, College of Veterinary Medicine, Chungnam National University, Daejeon 305-764, KoreaReceived March 4, 2003 / Accepted July 2, 2003J. Vet. Sci. (2003), 4(2), 187-191JOURNAL OFVeterinaryScience*Corresponding author: Myung-cheol Kim Laboratory of Veterinary Surgery, College of Veterinary Medicine, Chungnam National University, Daejeon 305-764, Korea Tel: +82-42-821-6757, Fax: +82-42-822-4216 E-mail: mckim@cnu.ac.kr

Atomic Force Microscopy를 이용한 Al0.5Ga0.5As/GaAs 다중 에피층 구조의 단면관찰에 관한 연구

김희진,김재성,김용,김무성,민석기 숙명여자대학교 자연과학연구소 1994 자연과학논문집 Vol.- No.5

다중 에피층 구조(Al0.5Ga0.5As/GaAs)의 단면을 AFM(atomic force microscopy)으로 관찰하는데 성공하였다. AFM을 이용한 다중 에피층 구조의 단면 관찰은 0.1M HCl을 이용해서 이미 다른 그룹에서 관찰한 바가 있으나, 본 실험에서는 처음으로 5% NaClO용액을 사용하여 시료를 선택에칭(stain etching)처리하였고, 선택적 산화와 에칭으로 AlGaAs와 GaAs를 서로 구분해 내었다. 5% NaClO로 처리한 시료의 AFM 이미지는 3초 미만 에칭하여도 관찰이 가능했다. 층간 구분이 선명하였고, 심지어 NaClO에 의한 GaAs층의 에칭 morphology까지 확인했다. 10mm정도의 구조는 쉽게 AFM을 이용해서 관찰이 가능했다. 반대로 0.1M HCl용액으로 에칭한 AFM이미지는 상대적으로 좋지 못한 것을 확인했고, 이것으로 HCl용액의 에칭선택성이 5% NaClO에 비해서 좋지 못함을 알 수 있었다. 5% NaClO용액을 사용한 단면관찰은 간단한 시료준비와 짧은 측정시간으로 nanostructure연구에 많은 활용이 있을 것으로 기대된다. We investigate the cross-section of Al0.5Ga0.5As/GaAs multilayered epitaxial structure by an atomic force microscope to see the feasibility of the technique. For the first time, we employ 5% NaClO etchant to discern each layer and obtain well resolved AFM images of the layers whose thicknesses are about nanometer scale. In contrary, we get relatively poor AFM images by applying. HCl etchants and it is attributed to poor Al0.5Ga0.5As/GaAs etching selectivity of HCl solution compared to that of 5% NaClO solution.

서울의 Penicillinase Producing Neisseria Gonorrhoeae 발생빈도(1994)

김재홍,안진균,정성재,김영태,김중환,김시영,이석종,이홍렬,서호석,김경훈,권혁진,정우권,고우석,이용석,안필수,오준규,오용섭 대한화학요법학회 1996 대한화학요법학회지 Vol.14 No.1

Background : In recent years gonorrhoea has been panendemic and remains one of the most common Sexually Transmitted Diseases in the world, especially in developing countries. Objective & Method : For the detection of a more effective therapeutic regimen and assessing the prevalence of Penicillinase Producing Neisseria Gonorrhoeae(PPNG), Ive have been trying to study the patients who have visited the VD Clinic of Choong-Ku Public Health Center in Seoul since 1980 by means of the chromogenic cephalosporin method. Results : In 1994, 168 strains of N. gonorrhoeae were isolated, among which 109 (64,9% ) were PPNG. Conclustion : Our results suggests that the prevalence of PPNG in Seoul is still increasing.

일부 의료서비스업 VDT작업자의 상지 근골격계 증상의 정도와 관련된 요인

김형렬,원종욱,송재석,김현수,김치년,노재훈 大韓産業醫學會 2003 대한직업환경의학회지 Vol.15 No.2

목적: 본 연구는 상지 근골격계 질환의 유병율이 높은 집단으로 알려진 VDT작업자를 대상으로 이들의 근골격계 통증을 정량화하고, 정량화된 통증점수를 종속변수로 하여, 이와 관련성을 갖는 작업요인, 사회심리적 요인을 파악하고자 하였다. 방법: 서울지역에 위치한 1500병상 규모의 대학병원에 근무하고 단말기 작업을 주로 수행한다고 알려진 부서에 대해 병원내 안전관리과와 협의를 거쳐 163명을 연구대상으로 선정하였다. 이중 138명이 설문에 참가하였고, 이들을 최종 연구대상으로 하였다. 설문지를 가지고 연구변수를 측정하여, 나이, 근무연수, 가사노동의 정도 등의 인구학적 변수와 직무스트레스 및 사회적지지, 근골격계 증상, 통증의 양상 등을 조사하였다. 분석방법은 일반적 특성 및 작업특성, 통증의 양상을 성별에 따라 파악하였고, 통증점수의 타당성을 검정하기 위해, 통증점수의 구성요소와 통증점수를 시각적 상사척도와 상관성 검정을 시행하였다. 통증점수를 종속변수로 하고 직무요구도, 직무재량도, 동료의지지, 상사의지지, 여러작업환경특성, 인구학적 특징 등을 독립변수로 하여 다중회귀분석을 시행하였다. 결과: 첫째 통증의 정량화를 위해 사용한 통증평정지수는 시각적 상사척도와의 상관관계가 높은 것으로 나타나, 어느 정도의 타당성을 지닌 방법으로 해석할 수 있었다. 둘째, 이 통증 점수를 종속변수로 하여, 관련요인 분석한 다중회귀분석에서 직무요구도가 높을수록 통증의 정도가 높고(p<0.01), 여성일수록 남성에 비해 높은 통증점수를 보였다(p<0.01). 결론: 근골격계 질환의 높은 유병율을 보이는 집단의 경우, 이들의 증상 유무만을 가지고 관련요인을 분석하는 방법을 사용하기 어렵다. 따라서 이런 경우, 통증을 정량화하여, 다양한 관련요인을 찾으려는 노력이 필요하며, 본 연구에서 사용한 통증평정지수는 타당성을 지닌 정량화 방법이라고 여겨진다. 또한 본 연구에서는 직무요구도가 높을수록, 여성일수록 높은 통증점수를 보였다. Objectives: This study was designed to quantify symptoms in the upper extremities and to identify the pain related factors among hospital workers using video display terminals. Methods: The subject-group consisted of 138 employees working at a hospital using video display terminals. A structured questionnaire was used to estimate the participants' general characteristics, and job contents. Job stress was measured using Karaseks JCQ(Job Content Questionnaire). Pain in the upper extremities was identified according to the NIOSH symptoms survey criteria. Quantification was measured using Kim Chul's method. Pearson's Correlation analysis was used to identify validity in quantification. VAS(visual analog scale) was used to compare with this method. Multiple regression analyses elucidated the relationship between quantified pain and various work factors, such as job stress. Data were analysed with SAS 6.12 program. Results: First, in quantification using Kim Chul's method, the correlation between modified PRS(pain rating score) and VAS was extremely high by 0.60(P<0.01), indicating the high validity of PRS. Second, the groups of high job demand, high job control, and females were related to an increased pain level. Conclusions: These results suggest that the self pain assessment method, PRS, is valuable and useful in analyzing occupational musculoskeletal symptoms. High demand, job control and gender may influence the levels of pain. Prospective studies about musculoskeletal disorder are required.

신경회로망에 의한 용접 결함 종류의 정량적인 자동인식 시스템 개발에 관한 연구

김재열,김영석,김병현,유신,김훈조,정진홍 한국공작기계학회 1997 한국생산제조학회지 Vol.6 No.1

A neural network approach has been developed to determine the depth of a surface breaking crack in a steel plate from ultrasonic backscattering data. The network is trained by the use of feedforward three-layered network together with a back-scattering algorithm for error correction. The signal used for crack insonification is a mode converted 70˚ transverse wave. A numerical analysis of back scattered field is carried out based on elastic wave theory, by the use of the boundary element method. The numerical data are calibrated by comparison with experimental data. The numerical analysis provides synthetic data for the training of the network. The training data have been calculated for cracks with specified increments of the crack depth. The performance of the network has been tested on other synthetic data and experimental data which are different form the training data.

성악골 절제술후 발생한 중앙부및 구개 결손부의 재건

김훈,임재석,최성원,김호겸,권종진,최미숙,김성문 大韓顎顔面成形再建外科學會 1996 Maxillofacial Plastic Reconstructive Surgery Vol.18 No.1

There are various defects caused by trauma or resection of maignant tumor in the orofacial region, which can be reconstructed with various regional and pararegional flaps. Among these defects, it is very difficult to reconstruct palatal and midfacial defects after maxillectomy and patients have problems in speaking and swallowing of food. Therefore it is very important for surgeons to reconstruct these defects functionally and esthetically and to return the patients to the normal social activity. These defects are usually obturated with prosthodontic appliances to assist the phonation and swallowing. But nowadays surgical reconstruction by various flaps was considered and performed for better rehabilitation. For this purpose the forehead flap, the nasolabial flap, the tongue flap, the sternocleidomastoideous flap, the temporal flap, the latissimus dorsi flap, the scapular flap etc. are used. We reconstructed small-sized plalatal defects with tongue flap, medium-sized palatal and maxillary defects after maxillectomy with temporal myofascial flap and large midfacial defects including eyeball exenteration with latissimus dorsi myocutaneous flaps. Here we are to report 5 cases of these flaps used for the reconstruction of palatal and midfacial defects and consider the versatility, reliability and limitation in use of these flaps.

주폐자충 폐렴으로 발현된 Felty 증후군 1예

김성호,남대근,문재현,김지홍,김보석,안진광,문태건,안병재,김성일 全南大醫大 2001 전남의대학술지 Vol.37 No.3

원위부 신세뇨관성 산증에서 산-염기 운반체의 결손

김혜영,한진석,전은실,진호준,주권욱,나기영,정우경,오지은,김현리,이서진,이중건,김근호,엄재호,궁성수,김진,이정상 대한신장학회 2000 대한신장학회잡지 Vol.19 No.5

口眼渦斜 患者의 Gadolinium-DPTA enhanced MRI 所見에 대한 臨床的 考察

김재수,최우석,김용석,고형균,강성길,김창환 경희대학교 동서의학연구소 2001 東西醫學硏究所 論文集 Vol.2000 No.-

This study is designed to evaluate the clinical implications of Gd-DPTA (Gadolinium-diethyl - enetriamine pentacetic acid) enhanced MRI(Magnetic resonance imaging) in Bell's palsy and find it's usefulness in Oriental Medicine In this study, 25 outpatients with Bell's palsy were studied that MRI was performed. To evaluate degree of facial palsy, H-B(House-Brackmann) Grade was used. In Oriental Medical therapy, Acupuncture and Herbal medicine were treated. Subjective causes was divided into exposure to chill, fatigue, stress, mixed cases. Enhanced site was compared with symptoms which were disorder of eye, hearing, taste, and facial muscle palsy. Also, Relation between time which was performed MRI and enhancement was analyzed. The enhanced lesion in MRI was divided into five segments; Internal auditory canal, Labyrinthine segment, Geniculate ganglion, Tympanic segment, Mastoid segment. In Bell's palsy, 20 of 25 patients(80%) had abnormal contrast enhancement of the facial nerve. The H-B grade and interval performed MRI from onset were directly proportionate to enhancement. That is to say, Severe facial palsy short interval show high possibility of enhancement. There was no relation between subjective causes and enhanced site of facial nerve in MRI. Also Clinical symptoms didn't coincide with MRI findings.