• Proceedings of the Korean Vacuum Society Conference
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• 2012.08a
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• pp.285-286
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• 2012

육각형 구조를 지닌 2차원의 물질인 그래핀은 우수한 전도도와 투과율로 투명전극의 신소재로 각광 받고 있다. 특히, 그래핀은 현재 투명전극으로 가장 많이 사용되고 있는 Indium Tin Oxide(ITO)로는 구현하기 힘든 Flexible display의 어플리케이션으로 사용하기 위한 목적으로 많은 기술 개발이 이루어지고 있다. 이러한 그래핀의 응용은 가장 먼저 그래핀의 생산이 안정적이고 원활히 이루어질 때 실질적으로 가능할 것이다. 하지만, 탄소로 이루어진 그래핀의 성장은 제한된 기판 위에서만 가능하기 때문에 성장이 이루어진 그래핀을 다른 기판에 전사시켜야하는 문제점이 있다. 그래핀 전사방법에는 직접전사, PMMA 전사, TRT 전사, 금속전사, 망전사, PDMS 전사 등 다양한 방법이 있다. 이 중에서 현재 가장 많이 사용되고 있는 전사방법으로는 직접전사, PMMA 전사, TRT 전사 방법이 있다. 직접전사의 경우 니켈위에 성장된 다층의 그래핀을 전사시킬 때 많이 사용되는 방법으로 니켈 에천트에 전사 시킬 그래핀을 띄워 니켈을 녹인 후 원하는 기판을 이용하여 전사하는 간단한 방법이다. 직접전사는 전사가 이루어진 후 그래핀에 남는 결함이 거의 존재 하지 않는 장점이 있지만 문제점은 단일층의 그래핀의 경우 니켈 에천트위에서 잘 보이지 않을 뿐 아니라 에천트에서 기판으로 전사할 때 너무 얇은 막으로 인해 다 찢어져버린다는 것이다. 이를 해결하기 위해 사용되는 전사 방법으로 TRT를 이용하여 구리위에 성장된 그래핀을 상온 시에는 점성을 가진 테이프를 이용해 부치고 구리에 천트에 구리를 녹인 후 원하는 기판위에 놓고 열을 가해 그래핀을 전사하는 방법이 있다. TRT 전사방법은 얇은 막의 그래핀을 찢어지지 않도록 지지해주어 대면적 기판위에도 전사 할 수 있는 장점이 있지만 전사 후 그래핀에 남아 있는 잔여물들이 많고(그림 1. (b)), 테이프를 이용한다는 점에서 그래핀의 얇은 막이 손상될 수 있는 단점이 있다. 그렇기 때문에 본 연구에서는 직접전사와 TRT전사의 문제점들인 전사 후 잔여물와 그래핀 단일층의 손상을 최소화할 수 있는 방법으로 PMMA전사를 가장 적합한 전사방법이라는 것을 라만 분석, 면 저항측정, 그래핀을 이용한 LED제작을 통해서 살펴 보았다. 먼저 라만 분석을 이용해 TRT전사 후 상당히 많은 빈 공간이 생김을 확인할 수 있었으며, 결과적으로 면 저항이 약 $1.5k{\Omega}$~$3M{\Omega}$까지 PMMA의 약 0.9~1.2 $k{\Omega}$와 비교했을 때 큰 차이가 있음을 확인할 수 있었다. 또한, 이후 각각의 전사방법으로 얻은 그래핀을 LED의 스프레딩 층으로 제작한 결과에서도 TRT전사방법보다 PMMA전사방법의 결과가 좋음을 알 수 있었다(그림 2).

• Journal of the Korean Geographical Society
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• v.43 no.4
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• pp.544-560
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• 2008

This study seeks to clarify the background and factors for the expansion of bus networks that connect Incheon International Airport with its hinterlands. For this research objective, this paper analyzes the relationships among the change of bus routes, competitive transportation modes, passenger fares, and the shortest time distance. Previously, the hinterlands of route bus networks that connect Gimpo International Airport were Seoul metropolitan area, Chungcheong region, Jeonju and Iksan in Jeollabuk-do(province). However, the opening of Incheon International Airport resulted in the expansion of the hinterlands of bus networks to Gangwon-do, Gwangju, and major cities in Youngnam region. Simultaneously, route bus networks also expanded in Seoul metropolitan area. Each bus route connecting Incheon International Airport with its hinterlands was opened by a single bus company or various bus companies. In many cases, due to the uncertainty of revenues or bus company's regional ties, a bus route was opened by various bus companies. In this paper, the analysis of the number of one-way route bus service and density of flight passengers shows that the frequency of the route bus service for Seoul except Gangseo-gu(ward) and for Seoul's satellite cities(Suwon, Seongnam, Anyang, Gunpo, Guri, and Osan) should be decreased. The analysis also shows that the frequency of the route bus services for the other cities, counties(Guns), and wards(gus) should be increased. In Seoul metropolitan area, although route bus fares are more expensive than subway fares, passengers use route bus more frequency than subway because time distance of route bus is shorter than that of subway and subway transfer is inconvenient. In general, outside Seoul metropolitan area, air flight is preferred in the regions that have airports. In contrast, the route bus is preferred in Daegu and other regions that do not have airports.

• Korean Journal of Crystallography
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• v.15 no.1
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• pp.5-8
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• 2004

The hydrothermal reaction of copper(I) bromide (CuBr) and pyrazine ($C_4H_4N_2$, pyz) gave a 2-D corrdination polymer [CuBr(pyz)] (1). X-ray structure determination revealed that polymer 1 has a 2-D network based on rectangular grids, each of which has the dimensions of 4.0${\times}$5.7 ${\AA}$. Polymer 1 has channels along the b-axis.

• 월간낙농육우
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• v.27 no.12 s.308
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• pp.92-95
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• 2007

지난 11월 14일(수) 국회의원회관 소회의실에서 육우의 군급식 방안을 모색하는 토론회가 개최되었다. 국회의원 서갑원(대통합민주신당)주최, 우리 협회와 전국낙농관련조합장협의회 주관으로 개최된 이날 토론회는 농림부 임상규 장관, 서갑원 의원(전남순천), 변재일 위원(축북청원), 윤호중 의원(경기구리), 김재윤 의원(제주서귀포), 참주인연합 긴선미 의원(경기안성) 등 국회 내빈들이 참석하였고 관련기관.단체 관계자를 비롯, 100여명의 육우농가들이 참석하는 등 많은 관심을 모은 가운데 성황리에 마쳤다. 이날 서갑원 의원은 "육우의 군납처럼 축산농가가 직접적인 수익을 확보할 수 있는 정책적 대안이 앞으로도 더 마련되어야 한다"고 하고 "수입쇠고기를 육우로 대체하는데 따른 추가재원 소요되므로, 내년도 예산에 반드시 반영하여 지원이 이뤄질 수 있도록 최선을 다하겠다"고 밝혔다. 그동안 협회에서는 국내 육우산업의 대책마련을 위해 농협하나로클럽 내 국내산 육우판매점의 입점, 육우전문브랜드 및 유통망 구축, 품질고급화 재개 및 보완, 한우수준의 육우농가의 경영안정방안 마련 등과 더불어 군급식에 육우가 수입육을 대체하도록 요구활동을 벌여온 바 있는데, 금번 토론회를 계기로 확실한 육우 소비확대 기반이 마련될 수 있기를 조심스레 기대해본다. 본고는 이날 토론회에서 이뤄진 주제발표 및 지정토론의 주요내용을 간단히 요약정리 한 것이니 많은 관심을 바란다.

• Korean Journal of Ichthyology
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• v.26 no.3
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• pp.159-170
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• 2014

The effect of substances discharged from copper alloy mesh on the survival rate, growth, and health status of Sebastes schlegeli was investigated. Survival rate of experimental group was 10% higher than control group. There was no significant difference in weight gain and SGR between control group and experiment group (P<0.05). Glucose concentration was lower in the experimental group than that in the control group. GOT and GPT contents did not show significant difference during experiment except for the early three months of experiment (P<0.05). Ammonia concentration had not significantly changed in the experimental group, but it had increased until four months of experiment and then decreased afterwards in the control group. TCHO had decreased in the experiment group compared with that of control group. Copper and zinc contents had increased as compared with those in the initial stage of experiment with no significant difference between experiment group and control group (P<0.05). Histological analysis for the liver revealed that liver tissues were not particularly different from those in control group. There were no significant differences in survival rate, growth, and hematological characteristic between control group and experiment group (P<0.05). Though copper and zinc were accumulated as compared with those during the initial stage of experiment, the levels were lower than permissible levels for copper and zinc. As a result, copper alloy mesh would not adversely affect on the survival rate, growth, and health status of fishes.

• The Journal of Korean Institute of Electromagnetic Engineering and Science
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• v.29 no.4
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• pp.277-284
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• 2018

This paper reports the transparent electrode, which would be applied to transparent displays and smart glasses. Herein, a squared metal mesh with the most widely used copper wire in microwaves is studied for the alternating thin-film-type transparent and conducting indium tin oxide(ITO), with a low conductivity(sheet resistance > $5{\Omega}/sq.$). The electromagnetic performance of a patch antenna with metal mesh is analyzed. This paper presents the results of the optical(OT, optical transparent) and electrical(sheet resistance) characteristics of a squared metal mesh, which is a basic design. To improve the OT, copper wire(w=0.2 mm) is used in fabricating the squared metal mesh and the relationship between the OT and the antenna performance(radiation gain, radiation pattern) was analyzed according to the mesh size(l=1, 2 mm). The measurement results show that the antenna performance and the optical characteristic are in inverse proportion to each other. In real applications, the optical and electrical characteristics, and the costs of production are to be considered.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.31 no.6B
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• pp.507-514
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• 2011

A numerical model has been developed by employing a finite element method to simulate the depth-averaged 2-D dispersion of the heat pollutant, which is an important pollutant material in natural streams. Among the finite element methods, the Streamline Upwind/Petrov Galerkin (SUPG) method was applied. Also both linear and quadratic elements can be applied so that irregular river boundaries can be easily represented. To show the movement of heat pollutants, the reaction term describing heat transfer was represented as an equation in which sink/source term is proportional to the difference between the equilibrium temperature and water surface temperature. The equation was expressed so that the water surface temperature changes according to the temperature transfer coefficient and the equilibrium temperature. For the calibration of the model developed, analytic and numerical results from a case of rectangular channel with full width continuous injection have been compared in a steady state. The comparisons showed that the numerical results were in good agreement with analytical solutions. The application site was selected from the downstream of Paldang dam to Jamsil submerged weir, and overall length of this site is about 22.5 km. The change of water temperature caused by the discharge from the Guri sewage treatment plant has been simulated, and results were similar to the observed data. Overall it is concluded that the developed model can represent the water temperature changes due to heat transport accurately. But the verification using observed data will further enhance the validity of the model.

• Korean Journal of Ecology and Environment
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• v.43 no.2
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• pp.255-262
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• 2010

This study was conducted at 5 sites of Bocheong Stream basin in May and September 2009 for the evaluate of fish assemblage and chemical water quality. For the study, the models of Index of Biological Integrity (IBI) and Qualitative Habitat Evaluation Index (QHEI) were modified as 8 and 11 metric attributes, respectively. We also analyzed patterns of chemical water quality at the sampling site over the period of 2005~2009, using the water chemistry dataset, obtained from the Ministry of Environment, Korea. The survey showed that total sampled fishes were 34 species and the most dominant species was Zacco platypus (24.3%). In Bocheong Stream basin, values of IBI averaged 28 (n=5), which is judged as a "Good". IBI score at B1, B4 and B5 indicating a "Good" condition whereas, B2 and B3 were as 21 and 22, indicating "Fair" condition, respectively. QHEI was 152 (n=5), judged as "Fair" habitat condition. Values of BOD and COD averaged 1.0 $mgL^{-1}$ (scope: 0.3~4.0 $mgL^{-1}$) and 2.3 $mgL^{-1}$ (scope: 0.3~18.7 $mgL^{-1}$), respectively. Total nitrogen (TN), total phosphorus (TP) and suspended solid (SS) were distinct spatial variation. Based on the IBI, QHEI and chemical water quality dataset, ecological health of Bocheong Stream basin was evaluated that generally good.

• Korean Journal of Ichthyology
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• v.23 no.2
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• pp.119-127
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• 2011

Fish species composition in eelgrass bed of Geoje island, Korea was determined using monthly samples collected by a surf net from August 2009 to July 2010. A total of 31 species, 1,387 individuals and 4,776.5 g of fishes were collected. The dominant species were Rudarius ercodes, Gymnogobius heptacanthus, Ditrema temminckii, Takifugu niphobles, Hypodytes rubripinnis, Chaenogobius annularis, Aulichthys japonicus, Syngnathus schlegeli, Pterogobius elapoides which accounted for 89.3% of total number of individuals of fish collected. Eelgrass biomass showed a peak in August (DW 154 g/$m^2$), low values in November (DW 31 g/$m^2$) to February (DW 41 g/$m^2$), and started growing from May (DW 78 g/$m^2$). The biomass of fish increased by the catch of a large number of Gymnogobius heptacanthus, Chaenogobius annularis, Pterogobius elapoides, Rudarius ercodes and Pseudoblennius percoides in May and September when the eelgrass grew fast. Meanwhile, Syngnathus schlegeli, Urocampus nanus and Aulichthys japonicus were collected year-round with no clear relationship to the biomass of eelgrass bed.

• Korean Journal of Agricultural and Forest Meteorology
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• v.6 no.1
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• pp.38-48
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• 2004

Tropospheric ozone data in Korea for 1998-2002 were analyzed to assess the impact on vegetation. SUM06(sum of hourly concentrations at or above 0.06 ppm) and AOT40(accumulated exposure over a threshold of 40 ppb), widely used as ozone indices in the U.S. and Europe, were calculated based on hourly ozone concentration in 612 areas during 1998-2002 in Korea. SUM06 of the highest 30 areas were 5-12 ppm/hr which were almost the same levels of the U.S. average, and a crop loss of 5% would be expected. Ozone pollution in Seoul during 1998-2002 had decreased compared to that for 1990-97 except in the Northern area; however, ozone pollution in Kyunggi during 1998-2002 had been increased twice compare to the previous 5 years. Korea was divided into four regions: Seoul Metropolitan area, Jungbu, Honam, and Youngnam. Ozone pollution in the Seoul Metropolitan area was much higher during 1998-2000 than the other areas, but ozone pollution during 2001-2002 was almost the same in all four regions. Chunnam-Kwangyang na Kyungbuk-Gumi, famous industrial complexes in southern Korea, were significant ozone pollution areas. However, other industrial complexes, such as Incheon, Ulsan, and Kyunggi-Sihwa, were not polluted compared to their neighbors. Comparing all ozone indices, SUM06(yr), SUM06(3mon), AOT40(yr), AOT40(3mon), number of hours exceeding 100 ppb, 95 percentile, 99 percentile, and maximum concentration, it was determined reasonable to use SUM06(3mon), AOT40(3mon) and number of hours exceeding 100 ppb for evaluation of the chronic impact of ozone on vegetation.