[논문]실험시설 기초의 진동사용성 분석

최형석,전법규,김남식,정진환 釜山大學校生産技術硏究所 2007 生産技術硏究所論文集 Vol.66 No.-

건물에 작용하는 진동하중은 구조물 자체의 성능에 영향을 미칠 뿐만 아니라 거주하는 사람이나 작업기계 동에 나쁜 영향을 가져올 수 있다. 본 연구에서는 이러한 진동에 대한 영향을 평가하는 국내외의 기준에 대하여 고찰하고 다양한 하중과 주파수 대역에서 실험이 가능한 대형지진모사 실험센터에 대한 진동영향 평가를 수행하여 사용성 저하 여부를 확인하였다.

석·골재의 분류 및 패턴 분류

남부희,박민현,김형배 강원대학교 부설 석재복합신소재 제품연구센터 2000 석재연 논문집 Vol.5 No.-

우리는 DWT를 적용하요 석ㆍ골재의 패턴 분류와 인식을 위한 테이타베이스를 구축하였다. 우선, 우리는 이미지의 각 row 벡터를 DWT를 수행하여 각 row 벡터마다 특징값을 얻는다. 그리고나서 같은 방법으로 row 벡터의 특징값을 이미지전체의 특징 값을 얻을 때가지 DWT를 반복해서 수행한다. 그런 다음 우리는 이미지의 히스트그램을 얻는다. 특징 값과 히스토그램은 이미지의 특징을 나타낸다. CCD 카메라로 새로운 이미지를 얻었을 때 우리는 먼저 특징 값과 히스트그램을 얻는 과정을 수행한다. 그 특징 값을 가지고 패턴 원형을 찾기 위해 저장된 특징 값과 비교하여 비슷한 값들을 찾아낸다. 그리고 입력 데이터의 히스트그램을 가지고 이전 과정에서 찾아낸 이미지들의 히스트그램과 비교하여 가장 유사한 패턴 원형을 찾아낸다. 이 방법은 석ㆍ골재의 자동분류를 할 수 있도록 하여 생상선 향상과 비용절감을 가능하게 한다. We built some database of stone and aggregate resources for classification and pattern recognition using DWT(discrete wavelet transform). First, we perform one dimensional DWT for each row of the image and obtain one value for each row of image. Then we perform again the same DWT for them to get a feature value. Next, we evaluate the histogram of input image data. The feature value and histogram represent the feature of image data. when an image data achieved by CCD camera, we perform same process again to get a feature value and a histogram. the feature value is compared with stored feature values to choose candidates. And then the histogram of input data is compared with some histogram value of candidates to find target image. this method can be adapted to automation of manufacturing of stone and aggregate resources for high quality low cost products.

익수환아의 예후에 영향을 미치는 인자에 관한 연구

김용배,정대봉,조수형,조남수,박영봉,박상기,김춘호,양은석,문경래 大韓應急醫學會 1998 대한응급의학회지 Vol.9 No.3

Drowning is the second most common cause of accidental death of children in Korea. But the study of near-drowning is very rare in Korea. The purpose of our study is to determine the factors that may influence survival on the basis of submersion time, consciousness state upon admission to hospital, the kinds of water, laboratory findings and neurological outcomes. The survey was performed by a retrospective cohort study on 28 near-drowning victims of less than 15 years of age who were admitted to the emergency room in the Chosun University Hospital between May 1988 & May 1997. The results were as follows :1)Sex distribution was 22 males and 6 females. 2) Submersion time was <5 minutes in 9 cases, 5-9 minutes in 6 cases, 10-14 minutes in 5cases, 15-19 minutes in 3 cases, ≥20 minutes in 5cases. 3) Comatose patients upon arrival were 6/7 cases in the death group(86%) and 2/21 cases in the improved group(10%). They had unfavorable outcomes(P<0.05). 4) The first PH value was mean 7.02±0.12 in the death group and mean 7.31±0.13 in the improved group. There was a statistically significant difference between the death and the improved group(P<0.05) 5) The patients who gad increased blood glucose concentration were all 7 cases in the death group and 12/22 cases in the improved group(54%). The mean blood glucose concentration was mean 424.7235.6㎎/㎗ in the death group and mean 140.182.7㎎/㎗ in the improved group. There was a statistically significant difference between the death and the improved group(P<0.05). 6) The patients who had pulmonary edema upon arrival were all 7 cases in the death group and 1/21 cases in the improved group(46%). They had unfavorable outcomes(P<0.05). 7) The patients who had been submerged more than 15 minutes were all 7 cases in the death group and 6/21 cases in the improved group(5%). They had unfavorable outcomes(P<0.05). We conclude that pediatric victims of near-drowning can be assigned to high or low likelihoods of unfavorable our outcomes with the use of five variables ; comatose mentation upon arrival decreased initial blood pH, increased initial blood glucose concentration, pulmonary edema, and maximum submersion time estimated longer than fiften minutes. This prediction rule may be useful if it can be validated in another cohort.

커뮤니티 개념을 적용한 도시하천 수변공간 정비방안에 관한 연구

김형태,이윤남,장준호 안양대학교 산업기술연구소 2002 自然科學硏究 Vol.9 No.-

급속한 도시화의 과정에서 기존의 도시하천정비는 공공의 논리로 이수, 치수목적에 큰 비중을 두었다. 그 결과 도시하천의 생태계 파괴는 물론, 획일적인 개발형태로 인하여 경관에 많은 문제점을 지니게 되었고, 특히 대도시 내에서의 하천은 그 경향이 심각하게 나타나게 됨에 따라 도시민에게 외면당하고 있는 실정이다. 따라서 본 연구에서는 이러한 문제점 해결방안으로 커뮤니티 개념을 적용한 접근 방법을 시도함으로써 새로운 문화와 상징을 창출하고 해당지역 주민에게 정비사업에의 참여를 통한 지역애와 지역공동체성을 함양시킬 수 있는 새로운 방안을 모색해보고자 한다. During the rapid urbanizing period, consolidating the urban waterfront system was likely to be regarded to leave the water or to regulate waterfront by the public logic. According to this research as a result, we have a lot of problems not only about the destruction of ecosystem but also about their appearance by the exact same development forms. As the problem is being more serious in the metropolitan areas, the residents don't care any more. So here, we are trying to solve this problem by approaching the concept of the community planning, so that we can creat the new cultural symbol and also we can make the fascinating space that people can feel their place more like home and give them comfortable through citizen participation.

다양한 절삭이송속도로 가공한 A1 7075-T6 소재의 쇼트피닝 전후 피로수명에 관한 연구

김형태,이재헌,신기훈,노승남,서성원 서울産業大學校 2005 논문집 Vol.54 No.1

Aluminum alloy 7075-T6 is ideally used for highly stressed parts such as aircraft components because of its excellent strength to weight ratio. This paper presents a study on the effect of feedrate changes on the fatigue life of A1 7075-T6 specimens before and after shotpeening. For this purpose, five groups of specimens, each of which consists of eight specimens, were first machined at five different feedrates (0.05, 0.10, 0.15, 0.20 0.25mm/rev). Half of eight specimens in each group were then peened and the others remained un-peened. Finally, the fatigue life of each specimen was measured by using 4-point rotatry bending machine. In this paper, comparison of fatigue life among ten sets of specimens is presented. One observation is that the fatigue life of unpeened specimens are inversely proportional to the feedrates. On the other hand, the fatigue life of peened specimens are similarly improved regardless of feedrates except 0.05. Based on the results, it is concluded that shotpeening may improve the fatigue life of Aluminium alloy regardless of feedrates. Therefore, machining productivity may also be increased by choosing higher feedrates for structural conponents that need to be strain-hardened by shotpeening after machining

중합효소연쇄 반응법에 의한 인형거대세포바이러스(human cytomegalovirus)의 신속한 검출

김의종,오명돈,박기호,신형식,이환종,김남중,최강원 대한감염학회 1996 감염 Vol.28 No.4

목 적 : 인형거대세포바이러스(HCMV)는 면역 저하 환자에서 폐렴, 망막염, 간염 등 치명적인 감염증의 원인이다. 전통적인 세포 배양법으로 HCMV를 분리하기까지는 1주에서 4주가 걸리므로 이 바이러스에 의한 질환이 의심되는 경우 신속한 진단법을 이용한 진단이 바람직하다. 저자들은 한국에서 분리되는 야생주 HCMV를 검출하는데 중합효소 연쇄 반응법을 이용할 경우의 진단적 유용성을 알기 위하여, 전통적인 세포배양법으로 HCMV가 분리된 검체를 이용하여 중합효소 연쇄 반응법의 특이도와 민감도를 평가하였다. 방 법 : 국내 야생주 HCMV 15주, 그리고 전통적인 바이러스 배양법으로 HCMV가 분리된 소변 15검체를 대상으로 중합효소 연쇄 반응을 실시하였다. 중합효소 연쇄 반응은 Towne주의 immediate early antigen의 유전자에서 유리된 primer MIE와 AD169주의 immediate early antigen의 유전자에서 유리된 primer IE를 이용하였다. 증폭 산물은 겔 전기영동 후 EtBR으로 염색하여 자외선 하에서 관찰하였다. Primer IE에 의한 증폭산물은 또한, DNA blot hybridization 방법으로 확인하였다. 결 과 : 1) 국내 HCMV 야생주 15주를 대상으로 중합효소 연쇄 반응을 한 결과 primer IE를 이용한 경우에는 100%(15/15)에서 177bp의 증폭 산물이 관찰되었고, 이들 증폭 산물은 모두 probe IE와 보합 결합되었다. primer MIE를 이용한 경우에는 93%(14/15)에서 435bp의 증폭 산물이 관찰되었다. 2) 세포 배양법으로 HCMV가 분리된 소변 15검체를 대상으로 primer IE를 이용하여 중합효소 연쇄 반응을 한 결과 direct gel analysis 법으로는 73%(11/15)에서, 보합 결합법으로는 87%(13/15)에서 관찰되었다. Primer MIE를 이용한 경우에는 direct gel analysis법으로 87%(13/15)에서 435bp의 증폭 산물이 검출되었다. 결 론 : Primer IE와 MIE를 이용한 중합효소 연쇄 반응법은 국내 야생주 HCMV를 신속히 검출하는데 유용한 검사법이다. Background : Human cytomegalovirus(HCMV) can cause pneumonitis, hepatitis, retinitis and other serious diseases in the immunocompromised patients. It takes 1 to 4 weeks to diagnose HCMV infection by conventional virus culture. Therefore, when HCMV diseases are suspected, a rapid diagnostic method such as polymerase chain reaction(PCR), antigen assay or shell vial culture is desirable. We evaluate the sensitivity and specificity of a PCR for the rapid detection of HCMV wild strains in Korea. Methods : We used 2 sets of primers ; primer IE and primer MIE derived from the sequence for immediate early gene of AD169 strain and Towne strain, respectively. Fifteen clinical isolates of HCMV, suspended in MRC-5 cells, were amplified by PCR. Fifteen urine specimens which were positive for HCMV by conventional virus culture were also amplified. Amplification products were analyzed by polyacrylamide gel electrophoresis. The products from PCR with primer IE were also identified by DNA blot hybridization. Results : PCR using primer IE gave the PCR products in all of the 15 HCMV wild strains. All of these were hybridized with probe IE. When primer MIE were used, 93%(14/15) of the wild strains showed amplified bands by direct gel analysis. When the urine specimens were amplified by PCR with primer IE, amplified bands were seen in 73%(11/15) by direct gel analysis ; 87%(13/15) by hybridization method. When primer MIE were used, 87%(13/15) of the urine specimens showed the PCR products by direct gel analysis. Conclusion : Polymerase chain reaction with primer IE and MIE may be a specific and sensitive diagnostic method for rapid detection of HCMV wild strains in Korea.

페롭스카이트 촉매를 이용한 메탄의 포름알데히드로의 부분산화반응

김영준,강춘형,김영철,박남국,신재순 全南大學校 觸媒硏究所 2002 觸媒硏究 論文集 Vol.23 No.-

The direct conversion of methane or natural gas into useful hydrocarbon and oxygenated products has been the subject of extensive research during the past decade. Partial oxidation of methane to formaldehyde was studied in a fixed-bed continuous flow reactor at the temperature range of 473-973 K using perovskite catalyst. La was taken as a basic material in A site. Ni, Co and Fe have been studied to test the catalytic activity and HCHO selectivity in partial oxidation of methane. Then La in A site was replaced by Ce and Co to study the activity change. TPR and XRD analysis were compared in view of the catalytic activity. The order of activity was observed in the flollowing order: LaNiO_3 > LaCoO_3 > LaFeO_3. The highest HCHO selectivity was 16.4% on reduced LaNi_0.8Co_0.2NiO_3 at 450℃.

저 소음/저 진동 철도 감속기 개발에 대한 연구

김인환,허남수,이형우 진주산업대학교 산업과학기술연구소 2003 산업과학기술연구소보 Vol.- No.10

A dynamic model of railway reduction is developed by the lumped parameter method. The model accounts for shafts, bearings flexibilities, gyroscopic effects and the force couplings among the transverse and torsion motions due to gearing. Excitation forces of railway reduction are considered as the mass unbalance of the rotors and a function of gear transmission error which comes from the modified tooth surface. A Campbell diagram, in which the excitation sources caused by the mass unbalance of the rotors and the transmittea errors of the gearing are considered, shows that, at the operating speed, there are not the critical speed The program which can be used to analyze and predict the vibrational characteristics by mass unbalance and gear transmission error of railway reduction is developed with this system model.

분말야금법으로 제조된 2124AI 합금의 빠른변형률속도 초소성 거동

金祐塡,張勝彦,南勝義,金亨駿 弘益大學校 科學基術硏究所 1999 科學技術硏究論文集 Vol.10 No.2

Ceramic whisker or particulate reinforced aluminum based metal matrix composites show high room temperature strength, but their low formability makes it difficult to form into desired shapes. By superplastic deformation, their formability can be improved and it is possible to produce complex parts for automotive aerospace simultaneously instead of many near-net-shape forming operations. This study has been carried out to investigate the high temperature mechanical and superplastic properties in 2124Al alloy. SRC(Strain Rate Change) tests show that the value of n(stress exponent) is around 3 at high strain rate and above 5 at low strain rate. It was turned out that 212Al matrix alloy exhibited reasonably high tensile elongation above 250% with the broad range of temperature and strain rate. Especially, at 550℃, both materials showed very high elongation failure up to 700% for 2124Al alloy. The strength comparison is lower strength then 2124Al composites were obtained that the composite is lower strength than 2124Al alloy at superplastic region.

간경화를 가진 환자의 척추 수술 후 발생한 급성 간부전 : 증례보고 A case report

김형남,최준석,박천희,이철승,김원태 全南大醫大 2001 전남의대학술지 Vol.37 No.4