• Korean journal of applied entomology
• /
• v.29 no.3
• /
• pp.184-189
• /
• 1990

A nuclear polyhedrosis virus (NPV) of the tobacco cutworm, Spodoptera litura would be a promisible agent for the control of the insect. To develop a viral insecticide using S. litura NPV, effect of spray on soybean leaves, temperature, storage, an sunlight on the pathogenicity of the virus were studies as follows: Median lethal concentration ($LC_{50}$) of the virus sprayed on the leaves against the third and the fifth instar larvae were $1.301\times10^{4 PIBS}/ml$ and $1.087\times10^{5 PIBS}/ml$, respectively. On the concentration of $1.0\times10^{5 PIBS}/ml$, median lethal times ($LT_{50}$) were 7.3 days for the 3rd and 8.9 days for the 5th instar larvae. Stability of S. litura NPV was quickly decreased at the higher temperate than $60^{\circ}C$ and at the longer exposure to the higher temperature. Storage of the virus at $-20^{\circ}C$ was kept higher pathogenicity than $4^{\circ}C$ and $25^{\circ}C$. Viral activity was maintained more than 10 days in the sprayed-under leaves, but decreased at 3 day after spray in th sprayed-on the leaf surface when exposed the virus to sunlight.

• Journal of the Korean Electrochemical Society
• /
• v.12 no.2
• /
• pp.148-154
• /
• 2009

With respect to the durability of large scale ($150cm^2$) membrane electrode assembly (MEA) of direct methanol fuel cell (DMFC), degradation phenomena at cathode is monitored and analyzed according to the position on the cathode surface. After constant current mode operation of large scale MEA for 500 hr, the MEA is divided into three parts along the cathode channel; (close to) inlet, middle, and (close to) outlet. The performance of each MEA is tested and it is revealed that the MEA from the cathode outlet of large MEA shows the worst performance. This is due to the catalyst degradation and GDL delamination caused by flooding at cathode outlet of large MEA during the 500 hr operation. Particularly on the catalyst degradation, the loss of electrochemically active surface area (ECSA) of catalyst gets worse along the cathode channel from inlet to outlet, of which the reason is believed to be loss of catalysts by dissolution and migration rather than their agglomeration. The extent of loss in the performance and catalyst degradation has strong relation to the cathode flooding and it is required to develop proper water management techniques and separator channel design to control the flooding.

• Convergence Security Journal
• /
• v.13 no.5
• /
• pp.27-35
• /
• 2013

There has been a adverse balance between Korea and U.S. in defense trade. This paper investigates the current status of the defense trade imbalance in terms of numerical values, and also analyzes the institutionalized barriers to Korea defense exporters imposed by laws and regulations. It is found that the amount of Korea defense import is several tenfold that of the export to U.S. in 2011. The barriers are analyzed to be the american laws and regulations. The buy american act is applied to the U.S government procurements and the Berry amendment is applied to the defense procurements. These two laws has been implemented by the defense federal acquisition regulation which allows U.S. Dept. of Defense to buy only american products. To overcome the barriers, Korea ought to sign a defense MOU with U.S., so that the buy american act and the Berry amendment can be waived.

• Proceedings of the Korea Water Resources Association Conference
• /
• 2009.05a
• /
• pp.1989-1993
• /
• 2009

댐의 조절방류가 하류 하천생태에 미는 영향은 매우 복잡하다. 하류생물상에 미치는 영향은 댐에서의 거리, 유황의 변화크기에 따라 달라진다. 흐르는 물에 서식하는 물고기는 좋아하는 수심, 유속 및 하상재질 등을 이용하여 살아간다. 다만 생물상은 주변환경에 적응하거나 변화하는 능력이 있어 댐의 조절방류에 의한 수생태계 변화구조를 명확히 해석하기는 불가능하다(Power et al., 1988). 댐에 의한 일정방류는 생물다양성을 감소시키며, 보다 변동성이 큰 방류하천은 하천, 연안 및 생물상 변화 유도에 긍정적인 것은 사실이다. 또한 큰 규모의 홍수파는 하천지형의 동적활동을 촉진시키며, 이는 하천을 터전으로 서식하는 동물상을 위한 생태학적 여건을 개선시켜 주게 된다. 이는 주변 식생의 생태적 조건 변화에 도움을 주기 때문에 적어도 1년에 2번 정도의 홍수파방류는 하천주변 서식처의 다양성 변화에 필요한 것으로 보고되고 있다(Kondolf and Wilcock, 1996). 최근들어 댐 하류하천의 생태복원을 위해 연속적인 홍수파 방류의 중요성이 강조되고 있는데(Stanford et al, 1996) 자연하도에서 댐과 같은 구조물에 의한 유량조절은 하중도나 사주 등을 발달시키고 사주에서는 두꺼운 식생층이 형성될 뿐만아니라 수목군의 현저한 출현을 보여준다. 이렇게 사주나 식생이 고착됨에 따라 이의 저항을 피해가는 수로가 형성되고 저수로 구간외에서는 식생의 발달이 더욱 왕성해져 그 면적이 확대되고 있다. 결국 사주와 사주가 식생으로 연결되고 여기에 수목이 자라면서 웬만한 홍수에도 파괴되지 않는 거대한 식생대가 출현하게 되는데 우리나라에서도 많은 하천에서 볼 수 있는 현상이다. 또한 댐에 의한 퇴사의 차단은 하천지형의 불균형을 초래하고 식생의 발달과 함께 저수도부는 좁아지고 세굴에 의해 깊어지는 현상을 보인다. 이와같은 현상들은 수문특성의 변화에 의하여 결국 댐의 조절방류에 의한 수문 변화는 하천지형의 변화를 유발하고 하천지형의 변화는 하천환경에 변화를 미치게 된다. 본 연구에서는 실제적으로 댐이 건설된 지역에서 조사된 몇몇의 자료를 분석하여 댐건설후에 나타나는 부정적 영향을 최소화하기 위한 바람직한 댐운영방안을 제시하고자 한다.

• 한국방재학회:학술대회논문집
• /
• 2011.02a
• /
• pp.190-190
• /
• 2011

사회 다변화 및 급속한 경제성장과 도시밀집화로 인하여, 화재의 발생으로 인하여 막대한 인명피해 및 대규모의 재산상의 피해가 지속적으로 발생하고 있다. 이러한 화재의 피해를 예측하기 위해서는 실제 규모의 화재실험이 매우 유용하지만, 막대한 비용과 현실적 제약조건으로 인하여 실제 실험에는 많은 어려움이 따른다. 따라서 막대한 예산이 소요되는 실제규모의 화재실험의 대체방법으로 실제를 모사하는 축소모형 화재모의실험 및 컴퓨터를 이용한 화재 시뮬레이션 기법이 널리 이용되고 있다. 본 논문에서는 범용 컴퓨터를 이용한 화재 시뮬레이션 기법(CFAST)을 이용하여 수직 공간 구성을 가지는 단독주택의 화재 성상을 검토하였다. 시뮬레이션 모델로는 단독주택을 대상건물로 하여 2층으로 수직 공간을 가지는 단독주택 건물에 대한 모의 화재 시뮬레이션을 수행 하였다. 화재 시뮬레이션 결과는 각 구획실별 온도, 일산화탄소량, 공기 중 산소량 등을 도출하여 기존 이론에 의한 화재성장 그래프와 시뮬레이션 데이터를 비교하여 정확도를 검토하였다. 본 논문에서는 두가지의 시나리오를 작성하여 화재 시뮬레이션 프로그램의 결과 값을 분석하였다. (1) 시나리오 1 : 화재시뮬레이션 대상건물 1층 거실(2번방)에서 스프링클러 미 설치시 화재가 발생한 경우를 가정하여 수평방향인 3번방과 수직방향인 7번방의 화재 확산 피해정도를 살펴보고, 화재 그래프의 이론값과 실험값의 차이를 비교하여 그 정합성을 검토하였다. 발화물질은 Curtain, TV set, Sofa, Table으로 하며 시간은 60초 간격으로 총 3600초(1시간)를 분석 하였고, 발화지점의 온도, 일산화탄소, 공기중 산소 농도를 분석하였다. (2) 시나리오 2 : 시나리오 1과 동일한 화재발현 조건으로 스프링클러가 설치되어 있을 때 화재 발생 했을 경우, 수평방향인 3번방과 수직방향인 7번방의 화재 확산 피해를 시나리오 1과 비교 검토 하였다. 기존 이론에 의한 화재 성장 그래프와 이번 시뮬레이션 결과값을 토대로 만든 그래프 형태를 비교해보면 두 그래프의 형태가 비슷한 형태를 나타내어 Flash Over 현상과 Back Draft 현상이 이론값과 같은 경향을 나타내고 있음을 확인 할 수 있었다. 따라서, 본 논문에서 수행한 화재 시뮬레이션 기법으로 건축물의 실제 화재시의 피해정도를 예측하는 데 유용하게 활용될 것으로 판단된다.

• Journal of the Korea Institute of Information and Communication Engineering
• /
• v.20 no.4
• /
• pp.799-804
• /
• 2016

To analyze the phenomenon of drain induced barrier lowering(DIBL) for top and bottom gate oxide thickness of asymmetric double gate MOSFET, the deviation of threshold voltage is investigated for drain voltage to have an effect on barrier height. The asymmetric double gate MOSFET has the characteristic to be able to fabricate differently top and bottom gate oxide thickness. DIBL is, therefore, analyzed for the change of top and bottom gate oxide thickness in this study, using the analytical potential distribution derived from Poisson equation. As a results, DIBL is greatly influenced by top and bottom gate oxide thickness. DIBL is linearly decreased in case top and bottom gate oxide thickness become smaller. The relation of channel length and DIBL is nonlinear. Top gate oxide thickness more influenced on DIBL than bottom gate oxide thickness in the case of high doping concentration in channel.

• The Journal of the Korea Contents Association
• /
• v.18 no.10
• /
• pp.348-360
• /
• 2018

Purpose : The purpose of this study was to explore the meaning and essence of experience of family members as care givers of patient with head and neck cancer. Methods : This study was based on the colaizzi's phenomenological method, which describes the experiences about the family care givers. We had in-depth interview with family of five head and neck cancer patients. Results : Data was classified by 24 themes, 9 theme clusters and 4 categories. The categories are as follows: 'Shocking and actuality like a deadly maze', 'Cut off from the world by changes in family's physical image', 'Exhaustion of family', 'Take-off for mature care'. Conclusion : The results of the study provide useful information in understanding care givers' experience of patient with head and neck cancer and establishing effective strategies to support these care givers.

• Proceedings of the Korean Institute of Navigation and Port Research Conference
• /
• 2017.11a
• /
• pp.61-63
• /
• 2017

The urban space has both aspects that the happy space that guarantees opportunity and comfort is an unfortunate space where poverty, exclusion and deportation proceed simultaneously. In other words, growth and decline are simultaneous within the city, and this phenomenon is more evident in modern society, which is getting more complicated. The harbor space is also affected by the growth and decline of the port industry directly or indirectly in the port area. However, since there is no systematic guideline for development and planning of port space in Korea, the phenomenon of the decline of the rear area, which is made up as if the harbor space has been growing and declining from past to present, is getting worse.

• The Korean Journal of Applied Statistics
• /
• v.24 no.3
• /
• pp.485-494
• /
• 2011

When the observations can take only the non-negative integer values, it is called the count data such as the numbers of car accidents, earthquakes, or insurance coverage. In general, the Poisson regression model has been used to model these count data; however, this model has a weakness in that it is restricted by the equality of the mean and the variance. On the other hand, the count data often tend to be too dispersed to allow the use of the Poisson model in practice because the variance of data is significantly larger than its mean due to heterogeneity within groups. When overdispersion is not taken into account, it is expected that the resulting parameter estimates or standard errors will be inefficient. Since coverage is the main issue for insurance, some accidents may not be covered by insurance, and the number covered by insurance may be zero. This paper considers the zero-inflated model for the count data including many zeros. The performance of this model has been investigated by using of real data with overdispersion and many zeros. The results indicate that the Zero-Inflated Negative Binomial Regression Model performs the best for model evaluation.

• Korean Journal of Social Welfare
• /
• v.63 no.2
• /
• pp.291-317
• /
• 2011

This study was designed to explore the experiences of female victims who had abused by alcohol-abusing spouse. The results were deducted from in-depth interview with 10 female victims by utilizing Giorgi's phenomenological method. The results of research showed that experiences of women could be classified in three stages. From the lack of understanding stage, "ignorance of drunken violence" had appeared. "Confinement of vicious circle of drunken violence" and "dealing with drunken violence in the community" had been found from the coping stage. Finally, from the resting stage "re-defining of the relationship" had been drawn. Based on these results, the practical and political implications were suggested.