• Proceedings of the Korea Air Pollution Research Association Conference
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• 2002.11a
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• pp.371-372
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• 2002

인천항은 한국의 주요항만의 하나로 원자재 수입 화물을 취급하는 항만이다. 수입 원자재 가운데 대두박 같은 사료 부 원료의 취급 시 강한 바람, 차량의 이동 저장시설에서의 상하차 등에 의해서 다량의 비산 먼지가 발생하며 이것이 주된 비산 먼지로 인천항만 주위의 주요 오염원이 되고 있는 실정이다. (Jeon et al.,2000) (중략)

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2002.11a
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• pp.312-313
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• 2002

도로에서의 비산먼지는 건설현장 트럭에 의한 토사의 유입, 운반 중에 날리는 토사, 토양의 침식, 겨울철 모래살포, 타이어의 마모 등에 의하여 도로표면에 쌓인 먼지가 차량의 운행이나 바람으로 인하여 발생한다. 국내 주요도시 및 산업단지는 대부분이 포장도로로서 주변환경에서 유입되는 먼지와 함께 차량의 운행으로 인한 비산먼지(Fugitive dust)의 영향이 지대하며, 건설현장에서 발생되는 비산먼지와 함께 도시·산단지역의 미세먼지 배출량에 큰 기여를 하는 것으로 조사되었다. (중략)

• Proceedings of the Korean Information Science Society Conference
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• 2000.10c
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• pp.487-489
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• 2000

회선분배장치를 제어관리하는 W/S의 Daemon 중에서 Event 처리를 담당하는 EvtProc Daemon의 경우를 들어 효율적인 부하 분산 알고리즘을 제안하였다. 본 논문에서는 대량의 Event 발생 시 담당 프로세스가 연속적으로 fork, exec 하지 않고 일정시간 대기함으로써 fork와 exec의 오버헤드를 줄이고 같은 Op Code의 연이은 Even 발생에 대기중인 프로세스가 이를 처리함으로써 더욱더 오버헤드를 줄일 수 있다. 그리고 Event를 처리하는 Child 생성에 있어 주 Child가 부하분산을 담당하게 함으로써 효율적이고 안정적으로 관리할 수 있는 방안을 제시하였다.

• Journal of the Mineralogical Society of Korea
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• v.19 no.4 s.50
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• pp.383-392
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• 2006

Calcium carbonate stone deterioration has been intensified in urban area, mainly due to the action of atmospheric pollutant. Samples from the black surface layer were examined under petrographic and scanning electron microscope, coupled with energy dispersive X-ray analyser X-ray fluorescence and X-ray diffraction analysis was also carried out for chemical composition and mineral phase analysis, respectively. Moreover, sulphur isotope ratio was measured, in order to identify the origin of sulphate compounds in the black surface layer. Optical and electronic petrographic analysis indicated that gypsum and Quartz were contained in the black surface layer and led to microcracks. Microstructure and chemical composition analysis showed that the interface between black layer and original stone is not black but its characteristic is similar to black layer The results indicated that during deterioration process the black layer can be expanded gradually into the interface by adsorption of atmospheric pollutants. The sulphur isotope analysis demonstrates that there are different origins of the sulphur component in black surface layer.

• International Commerce and Information Review
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• v.13 no.3
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• pp.377-401
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• 2011

Under the WTO system, direct export support system that provides financial and tax related support is altogether prohibited. This presented an obstacle in strengthening competitiveness of Korean export business and in increasing exports continuously. One of the methods used to solve this problem was to actively leverage export insurance. In Korea, export insurance services have been conducted by the Korea Trade Insurance Corporation (k-sure) to promote export. Korea has been among the world's active users of the export insurance system. Given this situation, this paper examines the effectiveness of the Korea export insurance system in the promotion of export. In particular, this study analyzed about discriminating effects of the export insurance on the export of big and small-medium business. In order to analyze, We introduce a Export Supply Function model. In this paper, We construct two model. The one is about big business, the other is small-medium business. For empirical analysis, unit-root test was conducted to understand the safety of time series. The results show that all variables are not I(0) time series. Instead, they are I(1) time series. To this, cointegration verification was conducted based on the use of Johansen verification method to define the existence (or non-existence) of long-term balance relationship among variables. The results come out as follows. The export insurance of big business has a stronger effect on export than that of small-medium business. The cause of these results is due to the distinct structure of Korea industries. In view of the fact that the insurance can make the risk decreased. We can say that the export insurance affects the export of a high-risk country.

• Korean Journal of Mineralogy and Petrology
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• v.33 no.4
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• pp.361-376
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• 2020

Atacamite and Verdigris were studied material scientific properties and durability that are used for traditional green pigment in traditional art painting work and Dancheong. As a result of ingrediant analysis, K-AA and K-VA identified Atacamite and Hoganite (or Verdigris) respectively. In order to find a factor of depressing the stability of pigment, we examined UV radiant exposure test, CO2/NO2 gas corrosion test and salt spray test. Salt spray test damaged both samples which were formed salt particle on the surface of the samples and it makes color disability. Furthermore, the results of gas corrosion test that both pigments change color enough to be perceived by the naked eyes showed that an air pollutant NO2 gas is also considered to be a major damage factor. In the case of K-VA, Hoganite that is main component of sample changes Tenorite with turn black after accelerated UV radiant exposure test. The consequences of the atmospheric environment effect test of the two pigments, K-VA showed relatetively weaker than K-AA.

• The Transactions of the Korean Institute of Power Electronics
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• v.16 no.1
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• pp.88-95
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• 2011

In this paper, a new standby-mode control method for multiple output switching-mode power-supply is suggested, which uses the control signal of the feedback compensator of the inner loop in the linear voltage regulator located at the transformer secondary side, as the load current information. Conventional method has a problem that standby mode occurs depending only on the load condition of the main controller output, which makes the other secondary side output very inaccurate by burst mode operation. The proposed method detects all the load current information and operates in burst mode only when the all of them are light load condition. Minimum of the additional components are required for the implementation of the proposed method because the load information is obtained from the existing feedback circuit of the post-stage linear regulator. In this paper, the operating principles of the proposed standby-mode circuit are presented with an numerical analysis, and are verified by 25W hardware prototype implementation.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.156-156
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• 2013

대기압 저온 플라즈마는 간단한 구조 및 제작, 쉬운 조작성, 낮은 온도 특성, 높은 화학적 반응성과 같은 많은 장점에도 불구하고, 플라즈마의 에너지가 낮아 다양한 산업적 응용에 제약을 받아왔다. 이러한 단점을 극복하기 위해서 대기압에서 저온 플라즈마의 에너지를 높이는 여러 시도가 있었으며, 그 중 가까이 인접해 있는 둘 이상의 플라즈마 젯들의 결합 현상(plasma jet-to-jet coupling)을 이용하여 플라즈마 강도를 높이려는 시도가 보고되었다. 본 연구에서는 플라즈마를 발생시키는 유리관을 서로 모아 벌집모양의 배열을 갖는 플라즈마 젯 어레이 장치를 만들어 플라즈마 젯 사이에 상호결합을 유도하여 강한 플라즈마 발광을 발생시켰다. 플라즈마 젯 어레이 장치 중 가운데 위치한 플라즈마 젯은 대기압 플라즈마 젯의 형태를 구현하는 역할을 하고, 가운데를 둘러싼 주변의 여러 플라즈마 젯들은 중앙의 플라즈마 젯에 많은 하전입자를 제공하여 플라즈마 젯의 발광강도를 높이는 역할을 하는 것을 확인했다. 헬륨기체를 사용한 이 플라즈마 젯은 $100^{\circ}C$ 이하의 온도임에도 불구하고 ITO 유리의 유리면을 식각할 만큼 높은 에너지를 가졌다. 이러한 대기압 저온플라즈마 장치에서 플라즈마의 강도를 더 높이기 위해서는 플라즈마 젯 간 결합이 더 많이 일어나는 것이 중요하므로, 이를 위해 주변의 플라즈마 젯의 개수를 높이는 시도를 하였다. 플라즈마 젯 어레이 소자의 중심에 위치한 유리관의 크기를 크게 하고, 주변부의 유리관의 크기를 상대적으로 작게 하여 벌집형태의 배열보다 더 많은 유리관을 주변부에 위치시킨 후 플라즈마를 발생시키고 전기 광학적 특성을 측정하였다. 그 결과, 실험조건에 따라 가운데 플라즈마 젯에서 3배에서 5배 이상 높은 플라즈마의 발광강도를 얻었으며, 플라즈마 젯도 더 안정적으로 발생하였다. 주변부의 유리관의 개수가 증가하면 더 많은 양의 하전 입자들이 플라즈마 결합 과정에 참여하게 되고 결과적으로 더 큰 플라즈마의 발광강도를 나타내는 것이다. 본 실험은 하전입자의 상호작용에 의해 발생하는 서로 인접한 플라즈마 젯 간의 결합이 대기압 저온 플라즈마 젯의 플라즈마 발광강도를 높이는 좋은 방법임을 보였다. 이러한 플라즈마 젯 간의 결합은 대기압 저온 플라즈마의 에너지를 높일 수 있는 쉽고 간단한 방법이며, 이 방법을 이용하여 대기압 저온 플라즈마를 표면처리, 표면개질은 물론, 식각 및 증착, 나아가서는 의료/바이오 분석 기술 등 다양한 학문적, 산업적 응용에도 적용할 수 있을 것으로 기대한다.

• Journal of Korean Society for Atmospheric Environment
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• v.8 no.2
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• pp.138-145
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• 1992

Dependence of the standard deviation of wind direction fluctuations, ${\sigma}_{\theta}$, on atmospheric stability, averaging time and topography were analysed with the data measured at three sites, Youngjongdo beach of the Yellow Sea, Chuncheon basin and Doam-Dam valley. The results show that the mean value of ${\sigma}_{\theta}$ is large in complex terrain, the Doam-Dam site. It is notable that the large value of ${\sigma}_{\theta}$ at night is associated with the low wind speed and the strong stable condition. In order to study the long-period fluctuations of the wind direction, ${\sigma}_{\theta}$ for longer than 10 minutes averaging time was further analysed using the data obtained at the Chuncheon basin. At the averaging time shorter than 60 minutes, larger ${\sigma}_{\theta}$ is associated with longer averaging time in the strong stable condition. However, ${\sigma}_{\theta}$ was not affected significantly by wind speed and averaging time in neutral conditions. The results of the spectrum analysis for the time series data of wind direction showed that low-frequency fluctuations ranging from 10 to 60 minutes were dominated at the Chuncheon basin in strong stable condition.

• Journal of Korean Society for Atmospheric Environment
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• v.12 no.4
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• pp.369-376
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• 1996

Major atmospheric stability classification methods were evaluated with meteorological data obtained by scoustic sounding profiler (SODAR/RASS) in Seoul. The Psequill classificatio method, the method most widely used because of its good agreement in respect of synoptic scope under the steady state, fails to describe the time lag, the response time on stability by heating or cooling caused by daily insolation or noctrunal surface radiation. Horizontal and vertical standard deviation of wind fluctuation $(\sigma_A and \sigma_E)$ method tend to classify night-time stable condition (E, F class) into unstable condition (A, B class). The classification matrix tables for Vogt's vertical temperature difference and wind speed using method ($\Delta$T $\cdot$ U) and bulk Richardson number (Rb) were amended for practical use over Seoul. The modified tables for $\Delta$T $\cdot$ U and Rb method were made by using comprehensive frequency distribution from Pasquill's method and other existing results, and the correlation coefficient(r) was equal to 0.829. It was confirmed that atmospheric stability could be changed with monitoring site characteristics, height and vertical difference between sensors of monitoring station, and classification method itself.