• 반도체디스플레이기술학회지
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• 제16권2호
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• pp.44-48
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• 2017

We explain optical and electrical properties of top and bottom-emission structured alternating-current powder electroluminescent devices (ACPELDs) with Ga-doped ZnO(GZO) transparent electrode. The top-emission ACPELDs were layered as the metal electrode/dielectric layer/emission layer/top transparent electrode and the bottom-emission ACPELDs were structured as the bottom transparent electrode/emission layer/dielectric layer/metal electrode. The yellow-emitting ZnS:Mn, Cu phosphor and the barium titanate dielectric layers were layered through the screen printing method. The GZO transparent electrode was deposited by the sputtering, its sheet resistivity is $275{\Omega}/{\Box}$. The transparency at the yellow EL peak was 98 % for GZO. Regardless of EL structures, EL spectra of ACPELDs were exponentially increased with increasing voltages and they were linearly increased with increasing frequencies. It suggests that the EL mechanism was attributed to the impact ionization by charges injected from the interface between emitting phosphor layer and the transparent electrode. The top-emission structure obtained higher EL intensity than the bottom-structure. In addition, charge densities for sinusoidal applied voltages were measured through Sawyer-Tower method.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 1998년도 춘계학술대회 논문집
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• pp.40-52
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• 1998

Among the non-traditional machining methods, Abrasive waterjet machining process shows big promise in drilling difficult-to-machine materials due to its numerous advantages such as absence of heat affect zone and thermal distortion. Acoustic emission signal technique is used to understand about material removal mechanisms during abrasive waterjet drilling process. More information about the drilling process is derived through frequency decomposition of auto regressive moving average modeling representing acoustic emission signals.

• 한국멀티미디어학회논문지
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• 제19권8호
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• pp.1371-1376
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• 2016

In this paper, an iterative method is proposed to perform attenuation correction and image reconstruction simultaneously for positron emission tomography, by using the time-of-flight information. Numerical simulation results are presented to demonstrate an improved performance of the proposed method in attenuation correction and image reconstruction.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2006년도 6th International Meeting on Information Display
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• pp.1206-1209
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• 2006

Carbon nanotubes (CNTs) have been significantly used for the field emitters for display applications. However, the lifetime of CNT emitters which are formed by screen printing technique is not guaranteed yet, because the constituents in CNT paste affect the lifetime of CNTs. The CNT pastes for screen printing are normally composed of organic vehicles (nitro cellulose, ethyl cellulose, etc) and additives (glass frits, ITO, etc) with CNTs. In this study, the effects of constituents in CNT pastes on the lifetime and emission characteristics of CNTs were investigated by thermal and electrical analysis. Use of glass frits worsened the lifetime and electron emission of CNTs. However, an addition of ITO to CNT paste rather improved the lifetime of CNTs. Degradation of CNTs was small when nitro cellulose was used in CNT paste as an organic vehicle.

• 한국환경과학회지
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• 제24권2호
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• pp.207-219
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• 2015

The purpose of this study is to show the geographical distribution and the temporal variation of the emission amount of biogenic volatile organic compounds(BVOCs) emanated from forests at Jeju Island. The total emission amount of BVOCs calculated by using the CORINAIR Methodology is $3612ton\;yr^{-1}$ at Jeju Island. More than half of BVOCs emissions is come from coniferous forest, and 45 per cent from broad leaved forest. The others is attributed to grassland. Of total emission of BVOCs, isoprene accounts for 28 per cent, monoterpene for 32 per cent, and other VOCs for about 40 percent, respectively. It can be shown that $3000{\sim}10000kg\;yr^{-1}$ of BVOCs is emitted at the zone with dense forest from an altitude of 500 m to the top of Mt. Halla, and less than $1500kg\;yr^{-1}$ at the zone an altitude of below 500 meters. The monoterpene emission is more than $1500kg\;yr^{-1}$ due to the existence of a colony of Abies koreana at the place with more than 1500 meters and a community of Pinus thunbergii and Cryptomeria japonica at the elevation of 500~700 m. In the case of isoprene emission, there is $1500{\sim}3000kg\;yr^{-1}$ at the zone of an elevation from 700 m to 1500 m due to dense broad leaved forest and very little of its emission at an elevation of more than 1500 meters because there is hardly broad leaved trees grown. In this study, emission of BVOCs according to the altitude above sea level is estimated under the situation of lack of the data for broad leaved tree. More detailed data and information for the distribution of broad leaved trees are needed in order to calculate more realistic BVOC emission.

• 농촌계획
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• 제19권4호
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• pp.125-135
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• 2013

Analysis and evaluation of uncertainty is adopting the advanced methodology among the methods for greenhouse gas emission assessment that was defined in GPS2000 (Good practice guideline 2000) and GPG-LULUCF (GPG Land Use, Land-Use Change and Forestry). In 2006 IPCC guideline, two approaches are suggested to explain the uncertainty for each section with a national net emission and a prediction value on uncertainty as follows; 1) Spread sheet calculation based on the error propagation algorithm that was simplified with some assumptions, and 2) Monte carlo simulation that can be utilized in general purposes. There are few researches on the agricultural field including greenhouse gas emission that is generated from livestock and cultivation lands due to lack of information for statistic data, emission coefficient, and complicated emission formula. The main objective of this study is to suggest an evaluation method for the uncertainty of greenhouse gas emission in agricultural field by means of intercomparison of the prediction value on uncertainties which were estimated by spread sheet calculation and monte carlo simulation. A statistic analysis for probability density function for uncertainty of emission rate was carried out by targeting livestock intestinal fermentation, excrements treatment, and direct/indirect emission from agricultural lands and rice cultivation. It was suggested to minimize uncertainty by means of extraction of emission coefficient according to each targeting section.

• 한국산학기술학회논문지
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• 제16권10호
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• pp.6466-6474
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• 2015

본 연구를 통해 배출업소 지도 점검 수행, 이력내용 관리 및 활용 등의 전반적인 지도.점검 이행 과정과 배출정보를 관리하고 활용하는데 발생하는 문제점을 도출하고 개선방안을 제언하였다. 업무담당자가 이용하고 있는 배출업소 지도 점검 업무 시스템을 분석하고, 업무담당자 설문 및 면담조사 등을 통하여 업무 및 배출정보 관리 실태를 분석하였다. 시군구행정정보시스템을 구조적, 업무활용 관점에서 구분하여 분석한 결과, 인허가중심으로 설계되어 이용자들은 시스템을 통해 지도 점검 업무의 지원을 받지 못하는 실정이었다. 업무담당자 면담 및 설문조사 결과, 지도.점검 결과의 입력, 배출정보의 지속적 유지관리가 어려운 실정이었다. 이는, 현재 시스템이 제대로 활용되지 않아 발생하는 문제로 볼 수 있다. 이러한 문제점을 토대로 국내에서 운영되는 유사시스템을 분석하여 시사점을 도출하고 개선방안을 제언하였다. 행정업무의 시스템화를 위한 간편한 업무처리화면 구축, 입력사항의 간소화, 지도.점검 및 배출정보 관련 업무 시스템의 연계, 배출정보 통계기능의 구축, 지리정보 기능 구축, 모바일 지도.점검 지원기능 등을 제언하였다.

• 한국환경농학회지
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• 제31권4호
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• pp.375-377
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• 2012

BACKGROUND: Hairy ventch (Vicia villosa) is a good green manure for supplying nitrogen in arable soil. Ammonia emission from rice fields can occur, and the degree of this emission can be great. However, quantitative information of ammonia emission from paddy soil using green manure is required to obtain emission factors for rice cropping in Korea. METHODS AND RESULTS: Ammonia emission from flooding soil with different application rate of hairy vetch was measured using the closed chamber method. For this study, hairy vetch was applied at rates of 0 (control), 500 (H500), 1000 (H1000), 2000 (H2000), and 3000 (H3000) kg/ha (fresh matter basis). This experiment was conducted for 54 days under flooding condition. The total NH3 emission throughout the experiment period was 0.32, 0.54, 1.20, 4.20, and 6.20 kg/ha for control, H500, H1000, H2000, and H3000, respectively. The ratio of NH3 emission to applied nitrogen by hairy vetch for each treatment was 0.7, 1.4, 3.2, and 3.2% for H500, H1000, H2000, and H3000, respectively. CONCLUSION(S): A very small amount of ammonia emission was recorded in the present study. Therefore, the use of hairy vetch in paddy field instead of chemical fertilizer can reduce ammonia emissions.

• 반도체디스플레이기술학회지
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• 제5권3호
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• pp.1-4
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• 2006

White-light-emitting ZnS:Mn, Cu, Cl phosphors with spherical shape and the size of $20\;{\mu}m$ are successfully synthesized. They have the double phases of cubic and hexagonal structures. They are applied to electroluminescent (EL) devices by silk screen method with the following structure: $electrode/BaTiO_3$ insulator layer ($50{\sim}60\;{\mu}m$)/ ZnS:Mn, Cu, Cl phosphor layer ($30{\sim}50\;{\mu}m$)/ITO glass. The EL devices are driven with the voltage of 100 V and the frequency of 400 Hz. The EL devices show the three emission peaks. The blue and green emission bands are originated from $CICu^{2+}$ transition and $ClCu^+$ transition, respectively. The yellow emission band results from $^4T^6A$ transition of $Mn^{2+}$ ion. As an increase of Cu concentrations, the blue and green emission intensities decrease whereas the yellow emission intensity increases; the quality becomes warm white. It is due to the energy transfer from the blue and green bands to the yellow band.

• Spatial Information Research
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• 제6권1호
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• pp.65-76
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• 1998

대기오염을 관리하기 위해서는 대기오염 농도와 함께 대기오염 배출량의 공간분포가 정확히 산정되어야 한다. 기존의 대기오염 분포도에서는 토지이용 분류도의 해상도(rdsolution)가 낮아 같은 위치에서 오염원별 토지이용이 중복되었기 때문에 배출량의 정확한 공간분포를 산정할 수 없었다. 본 연구에서는 토지이용분류도를 고해상도(28.5m x 28.5m)로 작성하므로써 이것이 배출량의 공간분포 산정과 대기오염농도의 추정에 미치는 영향을 파악하였는데, 결과를 요약하면 다음과 같다. GIS를 이용하여 비교적 고해상도(28.5m x 28.5m)의 토지이용 분류도를 작성하므로써 점 및 선 오염원이 면 오염원과 동일한 지점에서 중보되지 않도록 토지이용을 효율적으로 반영할 수 있었다. 서울지역에 대해 기존으 방법으로 작성된 배출량 분포도와 본 연구에서 작성된 배출량 분포도를 이용하여 대기오염 농도를 추정(TCM-2모형을 이용)한 결과 본 연구에서 작성한 배출량 분포도에 의한 대기오염 농도의 추정지가 자동측정망의 실측치에 근접함을 알 수 있었다.