• 환경정책연구
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• 제4권1호
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• pp.69-91
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• 2005

국내 주요 매립장 지역의 휘발성 유기화합물(VOC)에 대한 농도분포와 배출특성을 규명하기 위한 노력의 일환으로, 본 연구진은 주요 매립장지역에 대한 연구를 2000년 9월부터 2004년 12월까지 지속적으로 진행하였다. 본 연구의 일환으로 서울의 난지도 매립장을 위시한 전국의 7개 매립장을 주 조사대상으로 설정하였다. 본 연구에서는 여러 유형의 매립장으로부터 조사한 VOC 배출량자료를 토대로 VOC의 주요 배출원으로 간주할 수 있는 매립장 환경의 배출특성을 정의하고자 하였다. 이들 조사 대상은 1개의 대규모, 5개의 중규모, 2개의 소규모 매립장으로 구성되었다. 이들 지점으로부터 4년 이상 각매립장의 VOC 배출특성을 조사하였다. 이러한 연구자료는 향후 매립장의 VOC 배출에 대한 관리를 위한 여러 가지 기초자료로서 유용한 정보를 제공할 것으로 기대된다.

• 한국환경농학회지
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• 제40권4호
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• pp.295-312
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• 2021

BACKGROUND: Global warming is one of the most pressing environmental issues which concomitantly complicates global climate change. Methane emission is a balance between methanogenesis and methane consumption, both of which are driven by microbial actions in different ecosystems producing methane, one of the major greenhouse gases. Paddy fields are major sources of anthropogenic methane emissions and could be compounded by organic fertilization. METHODS AND RESULTS: Literature reviews were conducted to give an overview of the global warming conditions and to present the relationship of carbon and methane to greenhouse gas emissions, and the need to understand the underlying processes of methane emission. A more extensive review was done from studies on methane emission in paddy fields under organic fertilization with greater emphasis on long term amendments. Changes in paddy soils due to organic fertilization include alterations of the physicochemical properties and changes in biological components. There are diverse phylogenetic groups of methanogens and methane oxidizing bacteria involved in methane emission. Also, multiple factors influence methanogenesis and methane oxidation in rice paddy fields under organic fertilization and they should be greatly considered when developing mitigating steps in methane emission in paddy fields especially under long term organic fertilization. CONCLUSION(S): This review showed that organic fertilization, particularly for long term management practices, influenced both physicochemical and biological components of the paddy fields which could ultimately affect methanogenesis, methane oxidation, and methane emission. Understanding interrelated factors affecting methane emission helps create ways to mitigate their impact on global warming and climate change.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1996년도 추계학술대회 논문집
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• pp.56-60
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• 1996

An experimental study on the grinding temperature and Acoustic Emission(AE) signals due to the different shapes of wheel was conducted. The grinding characteristics by slotted shapes of wheel changed by width and helical angle, were compared with those by general one. Lower grinding temperature was obtained for 30$^{\circ}$ helical angle with 10mm width, Root Mean Square(RMS) values of AE signals were higher for slotted wheel rather than general one.

• 한국안전학회지
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• 제16권4호
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• pp.7-13
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• 2001

Wire electrical discharge machining experiments in conducted to investigate characteristics of acoustic emission (AE) and electrical discharge energy due to current peak (I$_{p}$), pulse on time($\tau$/on/). The AE signals are obtained with a sensor attached to workpiece side. Machining states are identified with scanning electron microscopy and residual stress analyzer. It is demonstrated that the residual stress provide reliable informations about the machining states. Moreover, machining states can be detected successfully using both the residual stress and AE count rate.e.

• 한국기후변화학회지
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• 제8권4호
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• pp.305-312
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• 2017

We aimed at investigating the difference in $N_2O$ emission factors of chemical and organic fertilizers and identifying the main factors influencing annual fluctuations in $N_2O$ emission. We conducted two-year experiments in 2016 and 2017 in an agricultural field planted with sweet potato (Ipomoea batatas). Treatments included chemical NPK fertilizer (NPK) and chicken compost application at $10\;ton\;ha^{-1}$, $20\;ton\;ha^{-1}$, and $30\;ton\;ha^{-1}$ rates (CK1, CK2 and CK3). Control was also employed with no addition. Results showed that $N_2O$ emission rates were significantly related with soil water status and soil available N contents. Significant correlation between % water filled pore space (WFPS) and $N_2O$ emission was observed only when the %WFPS was greater than 40% and during the initial stage of the experiment (<60 d). Comparison of the emission factors in 2016 and 2017 showed us that the emission factor was greater in 2016 when the %WFPS was maintained higher by 16.5% compared to that in 2017. In 2016, the emission factor of organic fertilizer was higher than that of chemical fertilizer, while in 2017, the pattern was reversed. Annual variability in $N_2O$ emission could also be originated from the available N contents remaining in soil after being taken up by plants. If we apply excessive N fertilizer, the soil would contain excess amount of N which was not uptaken by plants, leading to a huge increase in $N_2O$ emission. This case would overestimate emission factor, which was the case for the organic fertilizer in 2016. Over-fertilization should be avoided when we set up an experiment to determine $N_2O$ emission factor.

• 제어로봇시스템학회:학술대회논문집
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• 제어로봇시스템학회 2004년도 ICCAS
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• pp.470-473
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• 2004

This paper presents conducted emission noise measurement from electronic equipment in frequency range of 1 MHz up to 30 MHz by small loop antenna. Small loop antenna measurement method can measure common-mode (CM) and differential-mode (DM) component of the noise on a pair of power line at the same time. The CM and DM can be measured separately. The theory of this measurement method is introduced and analyzed. The measured results were compared with the conventional measurement by Line Impedance Stabilization Network (LISN) and result a good trend between those methods.

• Journal of Astronomy and Space Sciences
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• 제20권4호
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• pp.383-392
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• 2003

It is quite essential that requirements allocation and analysis would be done for the electromagnetic compatibility (EMC) of all units when designing a satellite. Although KOMPSAT-2 inherits relatively large portions of the electrical designs from KOMPSAT-1, it has a new instrument and different combinations of sensors and actuators as well as their driving circuitry. Many requirements for the electromagnetic compatibility were modified and newly allocated for KOMPSAT-2. Naturally, they must be justified through analyses from the early stage of the program. In this paper, the EMC compatibility requirements for KOMPSAT2 are presented and verified for their suitability. In addition, some results, which were obtained from various analyses, are presented and discussed.

• 한국군사과학기술학회지
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• 제17권5호
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• pp.569-576
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• 2014

There were overwhelming high-frequency electromagnetic noises in 200kW-class hybrid electric vehicle(HEV) although EMC control strategy had been applied to cope with the electromagnetic noises during the development of HEV. This paper investigates the characteristics of the conducted and radiated emission noises, the source and path of noises, and the effects of EMI on the electronics. Finally the design concept of noise control is proposed.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 A
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• pp.212-215
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• 1995

In this paper, The characteristic of Harmonic spectrum is studied for generally used three-phase diode rectifier. and filter design criteria is showen in the sense of THD, DPF, and PF. As the becoming of Automative and informative era, the demand of critical and stable control becomes more and more important. But much EMI emissions are generated for more critical and stable control in power electronic system these EMI emissions can be measured using LISN(Line Impedance Stabilization Network). So we are to investigate the behavior of Conducted EMI emission in Diode Rectifiers using LISN in frequency domain.

• 한국환경농학회지
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• 제32권4호
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• pp.366-368
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• 2013

BACKGROUND: Composting is the most frequently used waste management process for animal manure in Korea's livestock industry. In the composting process, a large amount of nitrogen (N) is volatilized to the atmosphere as amonia ($NH_3$). However, quantitative information of $NH_3$ emission from composting of liquid manure is required to obtain emission factors for management of livestock manure in Korea. METHODS AND RESULTS: To evaluate the $NH_3$ emission from composting of liquid manure affected by aeration, we conducted composting of liquid pig manure with three forced aeration systems. The aeration conditions were continuous (A60), cycle of 30 min aeration and 30 min pause (A30S30) and without aeration(A0). All treatments were aerated 12 hour per day with these aeration systems. The total ratio of $NH_3$ volatilization loss to total N content in liquid manure throughout composting period was estimated to 19.9% for A0 treatment, 25.9% for A30S30 treatment and 36.3% for A60 treatment. The A30S30 and A60 aeration systems increased $NH_3$ volatilization by 30.2 and 82.3% compared with systems without forced aeration. CONCLUSION(S): Ammonia emission during liquid pig manure composting was highly affected by forced aeration. The development of liquid pig manure composting systems with forced aeration would be considered both reducing ammonia emission and efficiency of composting.