• Korean Journal of Environment and Ecology
• /
• v.10 no.1
• /
• pp.76-86
• /
• 1996

We studied the degree of damage of trees which have been chronically damaged by environmental pollutants and the area of damaged stands in each region of the middle part of Korea with three tree species - Picea abies, Abies holophylla and Pinus densiflora. So as to diagnose the degree of tree damage in an early stage, We investigated injury index and measured contact angle and finally got the following results; 1) Visible and physiological damage such as the increase of injury index and the decrease of contact angle was serious centering around metropolitan cities live Seoul and Inchon; 2) The trees of all of 14 sites surveyed were damaged by environmental pollutants although there was difference to some extent among sites. Especially, the degree of damage appeared to be increased gradually in the western parts along including Inchon, the seacoasts. In fact, more systematic studies for this issue should be continued in other regions and countermeasures should be devised.

• Korean Journal of Ichthyology
• /
• v.11 no.1
• /
• pp.72-85
• /
• 1999

A study on the larval fish assemblage around the front area was conducted in the Korea Strait in August, 1993. The front was found in the shelf break located in $35{\sim}36^{\circ}N$. A total of 125 species were found in the study area. Of these Engraulis japonicus was the most dominant species comprising 84.3% of the total fish larvae collected and followed by Maurolicus muelleri accounting for 7.7%. Gobiidae, Callionymidae and Pomacentridae showed higher frequency of occurrence. These five species can be divided into three groups. First group was comprised in the larval fish species such as E. japonicus and Callionymidae which were found in the whole study area. The second group was comprised of Gobiidae and Pomacentridae which were found in the warm area located in the southern part of the front area. The other species was M. muelleri found in the cold area located in the northern part of the front area including the front area. The assemblage, geological distribution and body length composition of the fish larvae in the Korea Strait would be mainly determined by the spawning ecology of the fishes, and the geological distribution and structure of the front which is formed in the ocean boundary between the Tsushima Current and the East Sea Cold Water.

• Journal of Korean Academy of Nursing
• /
• v.27 no.4
• /
• pp.871-879
• /
• 1997

인간은 사회적 접촉을 필요로 하고 타인과의 상호작용을 원하는 사회적 동물이다. 외로움은 한 개인의 사회적 관계의 망이 양적이나 질적으로 부족할 때 발생하는 불유쾌한 감정이다. 외로움은 매우 보편적인 감정이나 고통스러울 수 있으며 이러한 경험이 지속되면 정신적, 신체적 건강을 해칠 수 있을 뿐 아니라 자살을 초래하기도 한다. 특히 노인은 여러 가지 종류의 변화와 상실을 경험하기 때문에 외로움을 더 느낄 수 있다. 본 연구의 목적은 번역과 역번역 과정을 통해 Revised UCLA Loneliness Scale에 대한 한국어 UCLA 외로움 사정도구를 만들고 이 도구를 한국노인에게 적용하여 신뢰도와 타당도를 조사하는 것이다. 개정판UCLA외로움 사정 도구는 각각 3번씩의 번역과 역번역 과정을 통해 원본 영문도구와 역번역된 영문도구 사이에 의미의 차이가 없다고 판단될 때까지 만들어졌다. 번역과 역번역 과정은 미국에서 석사나 박사학위를 취득한 6명의 한국유학생들에 의해 이루어 졌으며 원본 영문도구와 역번역된 도구사이의 의미의 차이는 본 저자와 미국인 간호학 교수에 의해 사정되었다. 번역된 한국어 외로움 사정도구는 미국의 3개 주에 거주하는 203명의 한국노인들을 대상으로 신뢰도와 타당도 조사가 이루어졌다. 한국어 UCLA외로움 사정도구의 신뢰계수는 .93으로 한국어 도구의 내용이 전반적으로 동질성을 띈다는 것을 알 수 있었다. 이는 Barren등(1992)이 미국인 노인여성을 대상으로 한 연구에서 얻은 신뢰계수 .87보다 높은 것이었다. 한국어 도구의 구성타당도를 조사하기 위해 요인 분석을 실시한 결과 본 도구는 친밀한 주변인, 사회적 주변인, 및 소속감 등의 3개 요인을 가지는 것으로 분석되었다. 구성타당도에 대한 이러한 결과는 미국의 대학생들을 대상으로 한 Austin(1983)의 연구결과와 일치하는 것이었다. 각 요인에 대한 신뢰계수는 .88(제 1요인), .90(제 2요인), .84(제 3요인)로 나타났다. 전반적으로 대상자들은 한국어 도구에 대해 이해를 잘 하는 편이었으나 부정문인 4번 항목, '나는 혼자라고 느끼지 않는다'에 대해서는 응답을 할 때는 다른 항목에 비해 시간이 더 소요되거나 연구보조자에 의한 반복 설명이 필요하기도 하였다.

• Transactions of the Korean Society of Mechanical Engineers
• /
• v.14 no.3
• /
• pp.624-635
• /
• 1990

Analytical study based on linear fracture mechanics was conducted on propagation behavior of inclined surface crack in semi-infinite elastic body. The analytical model was assumed to be inclined surface crack under plane strain condition upon which Hertzian stress was superimposed. Supposing continuous distribution of dislocation and applying Erdogan-Gupta's method to this crack problem, the stress intensity factors $K_{I}$ and $K_{II}$) at the crack-tip were obtained for various Hertzian contact positions. Analytic results have shown that driving force for crack growth is $K_{I}$ for non-lubricated condition and $K_{II}$ for fluid and boundary lubricated condition. The coefficient of friction at the hertzian contact and crack surfaces plays an important role in predicting the direction of crack propagation. It is also found that the maximum effective stress intensity factor exists at cracks of a certain specific length depending on lubricated condition.ion.n.

• Journal of Korean Society of Environmental Engineers
• /
• v.31 no.1
• /
• pp.51-57
• /
• 2009

Biofouling in seawater reverse osmosis (SWRO) desalination process causes many problems such as flux decline, biodegradation of membrane, increased cleaning time, and increased energy consumption and operational cost. Therefore biofouling is considered as the most critical problem in system operation. To control biofouling in early stage, detection of the most problematic bacteria causing biofouling is required. In this study, six model bacteria were chosen; Bacillus sp., Flavobacterium sp., Mycobacterium sp., Pseudomonas aeruginosa, Pseudomonas fluorescens, and Rhodobacter sp. based on report in the literature and phylogenetic analysis of seawater intake and fouled RO membrane. The adhesion to RO membrane, the high pressure resistance, and the hydrophobicity of the six model bacteria were examined to find out their fouling potential. Rhodobacter sp. and Mycobacterium sp. were found to attach very well to RO membrane surface compared to others used in this study. The test of hydrophobicity revealed that the bacteria which have high hydrophobicity or similar contact angle with RO membrane ($63^{\circ}$ of contact angle) easily attached to RO membrane surface. P. aeruginosa which is highly hydrophilic ($23.07^{\circ}$ of contact angle) showed the least adhesion characteristic among six model bacteria. After applying a pressure of 800 psi to the sample, Rhodobacter sp. was found to show the highest reduction rate; with 59-73% of the cells removed from the membrane under pressure. P. fluorescens on the other hand analyzed as the most pressure resistant bacteria among six model bacteria. The difference between reduction rates using direct counting and plate counting indicates that the viability of each model bacteria was affected significantly from the high pressure. Most cells subjected to high pressure were unable to form colonies even thought they maintained their structural integrity.

• Korean Journal of Applied Biomechanics
• /
• v.12 no.2
• /
• pp.215-227
• /
• 2002

The purpose of this study was to investigate propulsive time and kinematic variables on the three different kinds of the basketball wheelchairs in each play position for eight abled basketball wheelchair players. Kinematic data were collected by a video camera for two-dimensional analysis. The wheelchairs for the guard position showed the fastest in total propulsive time. The wheelchairs for the center position revealed the slowest in the phase of the change of the direction. The wheelchair for the guard position which shows fast movement velocity demonstrated closer hand contact with TDC(Top Dead Center). The wheelchair for the center position revealed the largest extension of the elbow and flexion of the trunk at handrim contact. The wheelchair for the guard position which has the lowest seat height presented larger elbow angle and trunk angle. The wheelchair for the guard position produced more fast trunk angular velocity than the wheelchair for other positions.

• Korean Journal of Culture and Social Issue
• /
• v.11 no.3
• /
• pp.23-40
• /
• 2005

The present study tried to explore relations among rape myth, types of sex role, and exposure of sexually obscene material. The specific purposes of this study were investigate (a) if there are differences in the degree of acceptance of a rape myth according to gender, school grades and types of sex role in participants, (b) whether the acceptance of rape myth are different by the types of sex role, and (c) whether the acceptance of rape myth is related with exposure of sexually obscene material. A total of 723 students in middle, high school, and university completed a questionnaire survey. The results of this study are as follows. First, male students accepted rape myth more than female students. In the level of male students, there were significant differences in acceptance of rape myth among three school students(middle, high school, and university). Secondly, types of sex role were not related with the acceptance of rape myth. Thirdly, the correlation between their exposure of sexually obscene material and the acceptance of rape myth was significantly high in middle school male students. Finally, implications and limitations of this study were discussed.

• 한국정보통신설비학회:학술대회논문집
• /
• 2004.08a
• /
• pp.226-229
• /
• 2004

본 논문은 초고주파 영역에서 개방 단말 동축선을 대신해서 복소 유전율을 측정할 수 있는 MEMS 프로브와 그 응용예로 MEMS 프로브 어레이를 제안한다. MEMS 프로브는 기존의 동축선 프로브와 달리 커넥터와의 연결이 간단하여 일회용으로 프로브를 사용할 수 있다는 점에서 의료용으로 사용할 수 있는 가능성이 있다. 샘플의 유전율 분포를 구하기 위해서 기존의 센서는 반복 접촉을 요구하고 이로 인한 번거로움과 측정 오차를 줄일 목적으로 MEMS 프로브 어레이를 개발 하였다. MEMS 프로브 어레이는 RF 스위치를 사용하여 다수의 측정 포인트를 한번의 센서 접촉으로 측정할 수 있는 새로운 개념의 프로브이다. 1GHz부터 40GHz까지의 광대역에서 0.9% 식염수의 유전율을 측정하여 MEMS 프로브의 성능을 검증하였다.

• The Bulletin of The Korean Astronomical Society
• /
• v.37 no.2
• /
• pp.143.2-143.2
• /
• 2012

2012년 3월 7일부터 5월 9일까지, 총 8일간 소백산 천문대의 61cm 반사망원경에 부착된 PIXIS 2K CCD와 Johnson-Cousins의 표준필터 BVRI 4색 필터를 이용하여 접촉쌍성 VW Boo의 전 위상에 걸친 광도곡선을 획득하였다. 이 관측으로부터 7개의 극심시각(주식: 4개, 부식: 3개)을 결정하였다. 우리의 극심시각을 포함하여 여러 문헌에서 수집한 총 201개의 극심시각을 이용하여 주기분석을 수행하였다. VW Boo의 주기는 약 74년에 걸쳐 영년주기감소와 규칙적인 변화를 겪은 것으로 나타났다. 영년 주기감소율은 년간 $-1.595{\times}10^{-7}$일이며, 규칙적인 변화의 주기와 반진폭은 각각 약 29.8년과 0.00667일로 산출되었다. 영년주기감소를 질량이 큰 주성에서 반성으로의 질량이동에 의한 것으로 가정하였을 때, 그 질량이동율은 년간 $-1.26{\times}10^{-7}M_{\odot}/yr$이다. 규칙적인 변화를 제3천체에 의한 광시간 효과로 가정하여 구한 3천체의 최소 질량은 $0.19M_{\odot}$이다. Wilson-Devinney 쌍성 모형을 이용하여 우리의 BVRI 광도곡선을 분석하였다. 이 때, 광도곡선에 나타난 역 O'Connell 효과를 설명하기 위하여 흑점모형을 도입하였고, W형과 A형의 두 가지 경우를 상정하여 광도곡선 해를 산출하였다. 그 결과의 천체물리학적 의미를 논의한다.

• Applied Chemistry for Engineering
• /
• v.8 no.6
• /
• pp.967-972
• /
• 1997

Recovery of aromatics in extract phase which was obtained by batch equilibrium extraction between light cycle oil(LCO) and dimethylsulfoxide(DMSO) solution as solvent was investigated by re-extraction. To select the most suitable re-extraction solvent for recovery of aromatics in extract phase, distribution equilibrium was measured between extract phase and solvents. The solvents used were benzene(B), toluene(T), m-Xylene(mX), n-hexane(Hx) and n-hexane(Hx) and n-Octane(Ot). From the distribution coefficients and yields of aromatics, Hx seemed to be the most suitable. Furthermore, effects of operation parameters for re-extraction of aromatics in the extract phase were studied by batch equilibrium re-extracion with Hx as solvent. Yields of aromatics were found to increase with increasing solvent/feed (extract phase) mass ratio(S/F), while distribution coefficients of aromatics were fixed irrespective of S/F used. Operating temperature did not affect distribution coefficients and yields of aromatics. Distibution coefficients and yields of naphthalene group(carbon numer : 10~12) increased with increasing cabon number. Mass transfer rates of aromatics were also measured with a batch stirred vessel.