• 한국전기전자재료학회논문지
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• 제24권2호
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• pp.162-165
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• 2011

In this paper, $CuInSe_2$ thin film was prepared by use of the co-evaporation method with the variation of the substrate temperature in the range of $100^{\circ}C$ to $400^{\circ}C$. The film was annealed at $300^{\circ}C$ for an hour in a vacuum chamber at $3{\times}10-4$ Pa. After annealing, the thin film prepared at the substrate temperatures of $100^{\circ}C$ and $200^{\circ}C$ was observed. The XRD (x-ray diffraction) pattern of sample prepared at $100^{\circ}C$ showed the single phase formation of $CuInSe_2$. However, at $200^{\circ}C$, there was no apparent difference in the XRD pattern except a variation in the intensity of the peak. As the annealing treatment of substrate improved the crystal structure of the film, it affected to the increase of an electron mobility, resulted in an increase in conductivity and a decrease in resistance. As a results, when the substrate temperature was at $200^{\circ}C$ and $300^{\circ}C$, the sheet resistance was 1.534 $\Omega/\Box$ and 1.554 $\Omega/\Box$, respectively, and the resistivity was $1.76{\times}10-6\;{\Omega}{\cdot}cm$ and $1.7210-6\;{\Omega}{\cdot}cm$, respectively. From the absorption spectrum measurements, there was no variation between the before and after annealing conductions. And it means that the annealing step does not affect the thickness of the thin film.

• 대기
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• 제19권3호
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• pp.227-235
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• 2009

Global climate warming induced by long-lived greenhouse gases is expected to cause increases in wildfire frequencies and intensity in boreal forest regions of mid- and high-latitudes in the future. Siberian forest fires are one of important sources for air pollutants such as ozone and aerosols over East Asia. Thus an accurate quantification of forest fire influences on air quality is crucial, in particular considering its higher occurrences expected under the future warming climate conditions. We here use the 3-D global chemical transport model (GEOS-Chem) with the satellite constrained fire emissions to quantify Siberian fire effects on ozone concentrations in East Asia. Our focus is mainly on spring 2003 when the largest fires occurred over Siberia in the past decade. We first evaluated the model by comparing to the EANET observations. The model reproduced observed ozone concentrations in spring 2003 with the high $R^2$ of 0.77 but slightly underestimated by 20%. Enhancements in seasonal mean ozone concentrations were estimated from the difference in simulations with and without Siberian fires and amounted up to 24 ppbv over Siberia. Effects of Siberian fires also resulted in 3-10 ppbv incresases in Korea and Japan. These increases account for about 5-15% of the ozone air quality standard of 60 ppbv in Korea, indicating a significant effect of Siberian fires on ozone concentrations. We found however that possible changes in regional meteorology due to Siberian fires may also affect air quality. Further study on the interaction between regional air quality and meteorology is necessary in the future.

• 한국수자원학회논문집
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• 제33권5호
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• pp.603-610
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• 2000

토양침식에 영향을 미치는 기후 인자로는 강우, 기온, 바람, 습도 및 태양열 복사 등이 있다. 이들 인자 중 강우는 토양침식에 직접적인 영항을 미친다. 강우의 운동에너지는 토립자의 이탈을 유발하며 강우로 인해 발생하는 흐름은 이탈 토립자를 연행시킨다. 토양침식을 예측하는데 있어 이러한 강우의 영향을 나타내는 지표의 설정은 중요한다. 본 연구에서는 범용토양유실공식(USLE)과 개정공식(RUSLE)의 강우침식도 R의 추정을 위해 1973년부터 1996년 까지 24년간 전국 53개 기상청 관측소의 강우 자료를 이용하였다. 본 연구에서 이용한 강우자료는 모든 관측소에 대해 동일 기간이며, 최근 24년간의 자료를 바탕으로 하고 있다. 본 연구의 최종 결과는 우리 나라의 등강우침식도로 나타내었다.

• Geomechanics and Engineering
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• 제16권1호
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• pp.21-34
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• 2018

Discontinuities considerably affect the mechanical and hydraulic properties of rock mass. These properties of the rock mass are influenced by the geometry of the discontinuities to a great extent. This paper aims to render an account of the geometrical parameters of several discontinuity sets related to the surrounding rock mass of Rudbar Lorestan Pumped Storage Power Plant powerhouse cavern making use of the linear and areal (circular and rectangular) sampling methods. Taking into consideration quite a large quantity of scanline and the window samplings used in this research, it was realized that the areal sampling methods are more time consuming and cost-effective than the linear methods. Having corrected the biases of the geometrical properties of the discontinuities, density (areal and volumetric) as well as the linear, areal and volumetric intensity accompanied by the other properties related to four sets of discontinuities were computed. There is an acceptable difference among the mean trace lengths measured using two linear and areal methods for the two joint sets. A 3D discrete fracture network generation code (3DFAM) has been developed to model the fracture network based on the mapped data. The code has been validated on the basis of numerous geometrical characteristics computed by use of the linear, areal sampling methods and volumetric method. Results of the linear sampling method have significant variations. So, the areal and volumetric methods are more efficient than the linear method and they are more appropriate for validation of 3D DFN (Discrete Fracture Network) codes.

• 한국항해항만학회지
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• 제41권3호
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• pp.103-108
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• 2017

이 연구에서는 최근 5년(2010~2014년) 동안의 데이터를 이용하여 우리나라의 풍랑특보 분포 특성에 대하여 분석하였다. 풍랑특보는 우리나라 주변 해역을 항해하는 선박 및 해양 구조물 등의 안전에 큰 영향을 미치므로 중요한 의미를 가진다. 풍랑특보는 한반도의 동측 즉, 동해남부 및 동해중부 해역, 남해동부 해역에서 많이 나타난다. 이 결과는 온대저기압의 이동과 발달, 계절풍의 세기 등과 밀접히 관련되어 있다. 그리고 풍랑특보는 12월에 가장 많고, 1월과 3~4월에도 높은 빈도수를 보인다. 계절로 구분해 보면, 겨울 > 봄 > 가을 > 여름의 관계를 확인할 수 있는데, 이들 결과는 온대저기압의 발생 및 발달, 계절풍의 세기 차이 등에 의한 것이다. 앞바다와 먼바다의 월별 풍랑특보 분포에 대하여 통계 분석한 결과, 양자는 강한 양의 상관관계가 있음을 확인하였다.

• Corrosion Science and Technology
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• 제6권3호
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• pp.103-111
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• 2007

The effect of stress factors on the growing process of stress corrosion cracking (SCC) of the sensitized 18-8 stainless steel in high temperature water was investigated using equations of crack growth rate derived from applying electric circuits to SCC corrosion paths. Three kinds of cross sections have to be considered when electric circuit is constructed using total current. The first is ion flow passage area, $S_{sol}$, of solution in crack, the second is total dissolving surface area, $S_{dis}$, of metal on electrode of crack tip and the third is dissolving cross section, $S_{met}$, of metal on grain boundary or in base metal or in welding metal. Stress may affect each area. $S_{sol}$ may depend on applied stress, $\sigma_{\infty}$, related with crack depth. $S_{dis}$ is expressed using a factor of $\varepsilon(K)$ and may depend on stress intensity factor, K only. SCC crack growth rate is ordinarily estimated using a variable of K only as stress factor. However it may be expected that SCC crack growth rate depends on both applied stress $\sigma_{\infty}$ and K or both crack depth and K from this consideration.$\varepsilon(K)$ is expressed as ${\varepsilon}(K)=h_2{\cdot}K^2+h_3{\cdot}K^3$ when $h_{2}$ and $h_{3}$ are coefficients. Also, relationships between SCC crack growth rate, da/dt and K were simulated and compared with the literature data of JBWR-VIP-04, NRC NUREG-0313 Rev.2 and SKIFS Draft. It was pointed out in CT test that the difference of distance between a point of application of force and the end of starter notch (starting point of fatigue crack) may be important to estimate SCC crack growth rate. An anode dissolution current density was quantitatively evaluated using a derived equation.

• 대한전자공학회논문지SP
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• 제47권5호
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• pp.212-221
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• 2010

해양에서는 해수면에 일어나는 여러 발생원들에 의해 많은 기포들이 생성될 수 있다. 이렇게 생성된 기포들은 해양에서 사용되는 음파의 세기와 음속에 영향을 미치게 된다. 본 연구에서는 이런 기포의 영향을 알아보고자 2008년 7월 2일 ~ 7월 3일 까지 동해 묵호항에서 약4Km 떨어진 해역에서 십자형 어레이인 Vbeam 송수신 장비를 사용하여 해수면의 Reverberation을 실측하였다. 수신된 신호는 주변 노이즈가 심하고 Multipath에 의해 ISI(Inter Symbol Interference)가 발생하기 때문에 자료 분석에 어려움이 있다. 본 논문에서는 입사각 추정 기반의 빔형성 기법과 Filter and Sum 기법을 적용하여 주변 노이즈와 ISI를 제거하였으며 완전하게 제거되지 않은 ISI를 제거하기 위해서 DFE(Decision Feedback Equalizer)를 적용하여 ISI에 의한 오차를 줄일 수 있었다.

• 한국수산과학회지
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• 제49권2호
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• pp.234-240
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• 2016

We examined the diffusion of contaminants released from the southern coast around Fukushima, Japan, during the passage of typhoons using a three-dimensional numerical model (POM) to track diffusing radioactivity (RA) released from the nuclear power plant at Fukushima following the accident caused by the giant tsunami event in March 2011. Radioactive contaminants released during the passage of typhoons may have significantly affected not only Japanese but also Korean coastal waters. The model domain covered most of the northwestern Pacific including marginal seas such as the East/Japan Sea and the Yellow Sea. Several numerical experiments were conducted case studies focusing on the westward diffusion from the southern coast of Japan of contaminants derived from the source site (Fukushima) according to various attributes of the typhoons, such as intensity, track, etc. The model produced the following results 1) significant amounts of contaminants were transported in a westward direction by easterly winds favorable for generating a coastal air stream along the southern Japanese coast, 2) the contaminants reached as far as Osaka Bay with the passage of typhoons, forced by a 5-day positive sinusoidal form with a (right-) northward track east of Fukushima, and 3) the range of contamination was significant, extending to the interior of the East/Japan Sea around the Tsugaru Strait. The model suggests that contaminants and/or radioactivity released from Fukushima with the passage of typhoons can affect Korean waters including the northeastern East/Japan Sea around the Tsugaru Strait, especially when the typhoon tracks are favorable for generating a westward coastal air stream along the southern Japanese coast.

• 한국해양학회지
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• 제28권4호
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• pp.281-291
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• 1993

대한 해협 및 황해의 해수수송량 변화와 수입자의 라그랑지안(Lagrangian) 이동경 로의 추적을 통하여 실제의 해저지형을 고려한 시간의존적 간략화된 2차원적 수치모델 의 계산을 수행하였다. 이 일련의 수치실험에서 에디에 의한 쿠로시오 해류의 지류들 은 대륙붕의 해류순환을 조율할 수 있을 정도의 충분한 강도를 지니고 있음을 보여준 다. 대륙붕 지역에서의 이러한 해수유입은 바람, 조류 및 부력 등과 같이 해수운동에 영향을 미치는 중요한 영향력들 중의 하나로 사료된다. 대륙붕사면의 해수수송량 변화 는 쿠로시오 지류, 특히 큐슈섬의 남서지역에서의 수송량 변화가 대한해협 및 황해 남부지역의 수송량과 밀접한 관련이 있음을 보여준다. 모델에 의한 수입자의 궤적은 WOCE/TOGA 계획의 일환으로 얻어진 인공위성추적 표류부의(drifter) 의 궤적과 잘 일 치하고 있으나 그 이동 시간이 현재의 모델에서는 다소 더 걸리고 있는 점이 다르다.

• 한국식품조리과학회지
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• 제21권5호
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• pp.607-615
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• 2005

The purpose of this study was to analyze the characteristics of Chinese foods in main ingredients, sauces, and cooking methods, and to assess the applicability of kochujang in Chinese foods. Twenty Chinese foods and commercial kochujang were selected by a Chinese head cook. The main ingredients were 24 kinds such as pork, chicken, shrimp, bok choy, bean curd, Chinese noodles etc., which were generally used in Korean foods. The main Chinese sauces were 11 kinds, and soy sauce was used in 12 foods, shang loo tau soy sauce in 2, wine in 8, oyster sauce in 7, rice wine in 6. The classification of cooking units in all Chinese foods was performed and the cooking frequency was deep frying>pan frying>boiling>stir frying>steaming>roasting. The proper amount of kochujang (weight ratio) was decided by pre-test of the Chinese head cook and Chinese food added kochujang was assessed by a Chinese focus group. The overall preference of Chinese food added kochujang was assessed highly and was related to the kinds of sauces, and to the kinds of main ingredients. The foods which used soy sauce or shang loa tau soy sauce were preferred. Sweetness by using kochujang wasn't preferred in several foods. Saltiness and aftertaste by using kochujang didn't affect the food preference, and the intensity of color and pungency were evaluated as a moderate level. An increased amount of kochujang would be possible in several foods. However, the increase in the amount of kochujang for intensive color and pungency in Chinese foods was directly related to the increase of sweetness, which had been discussed as the main problem in lowering the preference. Therefore, the screening of various Chinese foods harmonized with kochujang and the determination of the proper mixing ratio with Chinese sauces are very important. The results of this study could be used as basic data for the promotion of kochujang consumption in the Chinese market.