Ti-6Al-4V 합금의 동적변형특성과 탄도충격성능 : 1. 초고속 폭발충격 특성 1. Ultra-high-speed Exploding Properties

이유환,이동근,이성학,이종수,최준홍,허선무 대한금속재료학회 2003 대한금속·재료학회지 Vol.41 No.10

The effects of microstructural morphology on ultra-high-speed exploding properties of Ti-6Al-4V alloy were investigated in this study. Exploding bridge wire (EBW) test was conducted on equiaxed and bimodal microstructures, which were processed by different heat treatments. From the test, moving velocity of free surface vs time profiles were obtained to measure strength at Hugoniot elastic limit (HEL) and spall strength and to subsequently predict ballistic mass efficiency. The EBW results indicated that impact resistance of the bimodal microstructure was better than that of the equiaxed microstructure when the measured strength at HEL and spall strength were considered. It was also learned from the observation of fractured EBW specimens that fracture occurred by the initiation and propagation of long cracks in the equiaxed microstructure, whereas a number of microcracks were formed and connected each other in a zig-zag pattern to reduce the driving force for crack propagation in the bimodal microstructure. Since the EBW test helped experimentally estimate ultra-high-speed deformation and fracture behavior, it could be effectively used for the prediction of ballistic impact performance.

전도성 고분자 센서 어레이를 이용한 휘발성 유기 화합물 가스 인식

이경문,주병수,유준부,황하룡,이병수,이덕동,변형기,허증수 한국센서학회 2002 센서학회지 Vol.11 No.5

휘발성 유기 화합물 가스(Volatile Organic Compounds)를 인식하고 분석하기 위하여 전도성 고분자 센서어레이를 이용한 시스템을 제작하였다. Polypyrrole와 Polyaniline을 화학중합법으로 센서에 전도성고분자막을 형성하였고 이를 통해 VOC 검지용 센서 어레이를 제작하였다. 센서어레이로부터 측정되는 다차원 데이터는 주성분분석법(PCA)과 RBF(Radial Basis Function Network)을 이용하였다. 제안된 시스템으로 VOCs 가스를 인식하는데 있어서 RBF Network이 PCA방식보다 더욱 효율적인 것으로 판단되었다. We fabricated gas recognition system using conducting polymer sensor array for recognizing and analyzing VOCs(Volatile Organic Compounds) gases. The polypyrrole and polyaniline thin film sensors which were made by chemical polymerization were employed to detect VOCs. The multi-dimensional sensor signals obtained from the sensor array were analyzed using PCA(principal component analysis) technique and RBF(radial basis function) Network. Throughout the experimental trails, we confirmed that RBF Network is effective than PCA technique in identifying VOCs.

수근관 증후군에서의 무증상성 척골신경병증

문준식,이성수,이지용,한범기,권준범,양현덕,이성익 대한신경과학회 1999 대한신경과학회지 Vol.17 No.2

Impedance를 이용한 전도성고분자 센서의 가스감응특성

이경문,유준부,이병수,전희권,이상태,이덕동,허증수 경북대학교 센서기술연구소 2002 센서技術學術大會論文集 Vol.13 No.1

휴대폰 카메라용 자동초점 구동기의 충격해석

이성민,김봉석,송준호,이수훈,이혜진,이문구,송준엽,이창우 한국공작기계학회 2008 한국공작기계학회 춘계학술대회논문집 Vol.2008 No.-

Recently, the robustness against daily impact is important according to portablization and downsizing of mobile electronics. Especially, almost parts of cellular phone should undergo drop test when they fall 1.5 m above ground. This test simulates the case when cellular phone slips through user's fingers while he is talking on the phone. This paper studies a drop test of auto focusing (AF) actuator for camera module in cellular phone. This component is composed of voice coil motor (VCM) as an actuator and leaf spring as a guide and suspension. The leaf spring's deformation is essential for the test because its permanent distortion disables the focusing, and then, a high quality photograph cannot be obtained. Up to now the drop test has been carried out after fabricating real AF actuator. We propose a dropt test model which simulates the drop test based on finite element analysis. This model makes us enable investigate the stress acting on the clamping and curved parts of leaf spring. Stress over Von Mises criterion lets the spring deformed permanently, and then AF actuator malfunctioned, It helps us to design and modify AF actuator without manufacturing the real product. And also, it saves the time and cost for the development of new products.

소유-지배 괴리도가 경영진단의견서 공시에 미치는 영향

채수준(Chae, Soo-Joon),이아영(Lee, A-Young) 한국경영교육학회 2020 경영교육연구 Vol.35 No.4

[연구목적] 본 연구는 소유지배괴리도가 공시품질에 어떠한 영향을 미치는 지 분석하고자 하였다. 소유지배괴리도는 공정거래위원회가 ‘대규모기업집단 정보공개시스템’을 통해 제공하고 있는 지배주주의 소유권 및 지배권을 사용하여 측정하였으며, 공시품질로는 경영진단의견서(MD&A)를 고려하였다. [연구방법] 본 연구는 소유지배괴리도가 경영진단의견서 공시품질에 미치는 영향을 검증하기 위해서 2010년부터 2013년까지 유가증권시장에 상장된 1,483 기업-연도 표본을 대상으로 선형회귀분석을 실행하였다. [연구결과] 소유지배괴리도와 MD&A 공시품질 간에는 유의한 양(+)의 관련성이 존재하는 것으로 나타났다. 즉, 소유지배괴리도가 큰 기업일수록 MD&A 공시사항을 충실히 기재하고 있음을 확인하였다. 이는 상반된 두개의 해석을 가능하게 한다. 높은 소유지배괴리도로 인한 지배주주의 사익추구 가능성을 은폐하기 위한 수단으로 공시를 적극적으로 활용할 수 있다는 측면과 높은 소유지배괴리도로 인한 기업지배구조에 대한 부정적인 기업이미지를 해소하고 시장과 원활하게 소통하기 위해 공시를 활용할 수 있다는 해석이 가능하다. [연구의 시사점] 본 연구는 소유지배괴리도와 같은 기업의 소유구조가 기업의 공시품질에 영향을 미치는 요소임을 규명한다는 점에서 공헌도가 있다. 본 연구의 실증결과는 괴리도가 큰 기업일수록 MD&A와 같은 재량적 공시를 적극적으로 수행함으로써 소유구조에 따른 대리인 비용 및 정보비대칭을 완화하고자 하고 있음을 보여준다. 아울러, 대규모 기업집단 지정과 같은 규제제도가 기업들에게 스스로를 관리하게 하는 유인이 될 수 있음을 시사한다. [Purpose] The purpose of this study is to analyze how control-ownership wedge affects disclosure quality. We consider Management Discussion and Analysis(MD&A) as a proxy for disclosure quality [Methodology] This study conducted a linear regression analysis for 1,483 firm-year samples listed on the KOSPI market from the period between 2010 to 2013 to verify the effect of the ownership and control wedge on MD&A. [Findings] This paper showed that there is a significant positive (+) relationship between control-ownership wedge and MD&A disclosure quality. The results of this study verified that firms with a greater degree of control-ownership wedge faithfully described MD&A disclosure items. These results can be explained in two opposite directions. One explanation is that managers of firms with a greater degree of control-ownership wedge can actively use the MD&A disclosure as a mean to conceal the pursuit of the interests of the controlling shareholders. The other explanation is that the MD&A disclosure can be used to solve the negative corporate image of the corporate governance structure due to a high degree of control-ownership wedge and to communicate smoothly with the capital market. [Implications] This study has a contribution that the company’s ownership structure, such as the control-ownership wedge, is a factor influencing the disclosure quality of the company. The empirical results of this study show that firms with a greater degree of control-ownership wedge actively disclose the discretionary disclosure such as MD&A to alleviate agency cost and information asymmetries according to the ownership structure.

혼수상태의 외상환자에서 초음파를 이용한 흉부 및 복부손상의 진단

임경수,이강현,이진웅,이부수,황성오,유수영,강성준 대한응급의학회 1995 대한응급의학회지 Vol.6 No.1

The need for rapid diagnosis and treatment of life-threatening thoracic and intra-abdominal injury result in controversy over the appropriate triage of unconscious blunt trauma patients. To aid in early decisions for these patients, a prospective analysis of 98 patients with glasgow coma scale(GCS) scores≤8 was undertaken. Although intra-thoracic and intra-abdominal injuries were frequently identified based on systolic blood ressure, the use of clinical signs alone resulted in more missed injuries than did using the emergency ultrasonography. In normotensive patients(n=34), intra-thoracic injuries was identified in one patient(2.9%), and intra-abdominal injuries were in 7 patients(20.6%). In shock(systolic blood pressure<90mmHg) Pa-tients(n=64), thoracic injuries and intra-abdominal injuries were diagnosed in 8(12.5%) and 27 patients(42.3%), thoracic and abdominal combined injuries were identified in 11 patients(17.2%). The sensitivity, specificity, and accuracy of emergency ultrasonography were 96.3%, 91.7%, 94.9%. This study suggests that all unconscious trauma patients undergo immediate emergency ultrasonography to prevent missing life-threatening injuries.

전북 林業試驗場 시험림內 植生別 토양응애類의 分布 및 諸 要因에 關한 硏究

李丙璇,金泰興,郭晙洙 全北大學校 1992 論文集 Vol.34 No.-

This study investigates the distribution of soil mite communities and various abiotic factors under different types of vegetation. Soil samples were taken on September 23 in 1987 and January 28, April 13, and July 9 in 1988 from five sample sites at the Forest Research Institute located in Chonbuk Province. Individuals of 5,475 soil mites were collected in this study. Among them 39 families, 62 genera, 119 species, and 4,312 individuals were classified into oribatid mites. Species similiarity index showed highest between the site D(Chamecypatis obtusa) and E(Cryptomeria japonica) where the environmental factors such as the altitude, pH, and the content of potassium in soil were similar. Seasonal changes in density of soil mites showed highest peaks in September and April, while lowest in July. Correlation coefficients between the density of soil mites and pH, OM, soil moisture, and the content of potassium in soil were statistically significant. Major abiotic factors that affected the distribution of soil mites were soil moisture, potassium, organic matters, and pH.

완전 기저 동맥 중복과 동반된 모야모야병(Moyamoya disease) 1예

권준범,양현덕,한범기,이지용,문준식,이성수 대한신경과학회 1999 대한신경과학회지 Vol.17 No.2

직장레크리에이션에 관한 연구

이준수,김상구 江原大學校附設 體育科學硏究所 1992 江原大學校附設體育科學硏究所論文集 Vol.- No.17

The purpose of this study was find out several protits refer to industrial recreation, An extensive activity of recreation has been undergone, but it is instrumentally exist in poorness, It appears to be reaching about 60% the canons of facilities by National sports promotion act. It shows that each industry viorated a canons. Nevertheless activity of recreation was completed by devices. Thus it was the Poverty of instrument that limited the activation of industrial recreation. Severals of proposal required that level of practical instrument was handed in and power of adminstration was disciplined in order to solve this affairs. We must be activation of industrial recreation and development of program could be used it most of salary man, put under an obligation to industry that employed receation leaders.