• 환경영향평가
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• 제14권3호
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• pp.117-126
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• 2005

This study was executed to know the best matrix of photochemical ozone reduction in the metropolitan area. For this object, we used the OZIPR(Ozone Isopleth Plotting Package for Research) model for comparing the effectiveness of VOCs and NOx amount variation about the ozone creation. Among the various ozone reduction scenarios, 50% reduction of VOCs from organic solvent and road traffic respectively was the best matrix for ozone reduction. Although it needs more accurate assessment and confirmation of VOCs and NOx emission amount data, according to existing data, the control of VOCs is the best way for photochemical ozone reduction in Seoul.

• 동력기계공학회지
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• 제10권1호
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• pp.12-18
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• 2006

A three-degree of freedom model of intake system was contrived and investigated in various ways for the purpose of the amelioration of the volumetric efficiency in a low and transient engine speed for a multi cylinder diesel engine. The basic concept beyond this model started from the theory that each degree of freedom model has volumetric efficiency peak as many as its number of the degree of freedom. The volumetric efficiency affects significantly to the engine performance; torque characteristics, fuel economy and emission level. For commercial vehicles and stationary engines, the engine is designed so as to produce their best performance near the normal engine speeds, thus the low engine speed area has a tendency of poor volumetric efficiency. The aim of this study was highlighted on the amelioration of volumetric efficiency of low engine speed area in a multi cylinder diesel engine matched with an additional Helmholtz resonator. By the use of VIS(variable induction system) volumetric efficiency at low engine speed range was significantly improved. The availability of control by combination of VIS and CIS(conventional induction system) will be proposed as a variable induction system that would be an appropriate model for amelioration of the volumetric efficiency at low engine speed.

• Journal of Electrical Engineering and Technology
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• 제1권2호
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• pp.246-250
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• 2006

Highly ordered gold nanodot arrays have been successfully obtained by vacuum evaporation using an anodic aluminum oxide (AAO) as a shadow mask. An AAO mask with the thickness of 300 um was prepared through an anodization process. The structure of the nanodot arrays was studied by a field- emission scanning electron microscope (FE-SEM) equipped with an energy dispersive spectrometer (EDS). A tapping mode atomic force microscope (AFM) was employed for studies of height and phase feature. The nanodot arrays were precisely reproduced corresponding to the hexagonal structure of the AAO mask in a large area. In the gold nanodot arrays, the average diameter of dots is approximately the same as the AAO pore size in the range from 70 um to 80 nm and 100 nm center-to-center spacing. EDS analysis indicated that the gold dots were almost entirely consisted of gold, a highly demanded material.

• 한국세라믹학회지
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• 제49권5호
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• pp.423-426
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• 2012

$Al_2O_3$/NiO powder was obtained through hydrolysis-condensation reactions and thermal treatments. An organic additive, triblock copolymer surfactant P123, was added to the starting materials to control the surface area and morphology. The synthesized powder was characterized by X-ray diffractometry (XRD), field-emission scanning electron microscopy (FE-SEM) and a Brunner-Emmett-Teller surface analysis (BET). The heterogeneous catalytic activity of this powder was applied to an epoxidation reaction of styrene and was monitored using a gas chromatograph with mass spectrophotometry (GC/MS).

• 한국자동차공학회논문집
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• 제11권1호
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• pp.87-94
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• 2003

Recently, LPLi(Liquied-Phase LPG injection) system is studied for the new stringent emission regulations. But , there are some problems to be solved such as injector tip icing and fuel leakage for LPLi system development. In this paper, the icing problem near injector tip which leads to difficulty of accurate A/F control was studied and reported. Icing of injector tip and port wall was observed at all the cases in this study regardless of injection duration and angle, air humidity change. The spray angle of LPLi was observed approximately two times wider than that of Gasoline injection. This makes the LPLi spray collide with intake port around injector tip. Temperature of the wetted area was decreased and icing of water vapor contained in intake air because of evaporation of the fuel film. The ice of the injector tip and port wall is also affected by the materials related to heat transfer.

• 센서학회지
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• 제25권3호
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• pp.178-183
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• 2016

Semiconductor gas sensors based on metal oxide are widely used in a number of applications, from health and safety to energy efficiency and emission control. Nanomaterials including nanowires, nanorods, and nanoparticles have dominated the research focus in this field owing to their large number of surface sites that facilitate surface reactions. Recently, metal oxide hollow structures using soft templates have been developed owing to their high sensing properties with large-area uniformity. Here, we provide a brief overview of metal oxide hollow structures and their gas-sensing properties from the aspects of template size, morphology, and additives. In addition, a gas-sensing mechanism and perspectives are presented.

• 대한방사선기술학회지:방사선기술과학
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• 제19권1호
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• pp.89-94
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• 1996

Misalignment between the electronic and mechanical axes of rotation will result in artifact generation and image degradation during single photon emission computed tomography(SPECT) reconstruction. Acceptance and quality control testing procedures have not emphasized the variability in center of rotation(COR) measurements caused by collimators and the need to verify uniformity across the full collimator field of view (FOV). Variation from the mean COR across the FOV was tested in four different collimators using multiple point source acquisitions. The mean COR was different for each collimator and one of the four had a > 0.5 pixel difference from the mean COR on some area of the FOV, This variation makes this collimator unacceptable for SPECT acquisition. Thus, initial acceptance testing of SPECT collimators should verify a uniform COR across the full FOV and collimators with a variability from the mean COR > 0.5 pixels should be rejected.

• 한국항해항만학회:학술대회논문집
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• 한국항해항만학회 2018년도 추계학술대회
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• pp.357-357
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• 2018

국제해사기구(IMO)에서는 황산화물(SOx)에 대한 배출 규제를 강화하고 있다. 2020년 1월 1일부터는 황함유량 0.5% 이하 선박연료유 사용을 의무화하고 있다. 그리고 온실가스 배출량 모니터링을 2019년 1월 1월부터 시행하여 총톤수 5천톤 이상 선박은 연료유 사용량을 의무적으로 보고해야 한다. 또한 배출통제구역(Emission Control Area, ECA)이 확대되고 있으며 지역별로도 저유황유 사용 의무화를 도입하는 항만이 증가하고 있다. 이와 같이 항만구역에서 선박 배기가스 배출 규제를 강화하고 있다. 본 연구에서는 컨테이너 물동량이 증가하고 있는 서산 대산항 컨테이너 부두를 중심으로 항만구역에서 배출되는 배기가스를 산출하였다.

• Journal of Advanced Marine Engineering and Technology
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• 제30권1호
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• pp.102-108
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• 2006

On the refutation demanded for a control of various toxic substances. PCBs(poly chlorinated biphenyl) has a fatal poisonous matter in the ecosystem and the environmental pollution as it Is a kind of stable chemical substance. Especially, the gross Product of PCBs is estimated at about one million tonnage all over the world. However it is kept on storing in untreated state, then has a deterioration by the Prolonged storage and a risk of overflowing. Therefore, this research examined the fundamental characteristics of combustion and emission for the target of using the IPA (iso-propyl alcohol) solution as a part of PCBs control. IPA was filled to three kinds of Vessel, i.e. Vessel I, II, and III, and then was investigated as follows combustion shape, flame temperature. mass burning velocity, and PM(Particulate matter). A radial thermometer and a C-A thermocouple measured the flame temperature, and the optical extinction method by using He-Ne laser and the filter weight method used in the PM measurement. As a result, with an increasing of L/S ratio, the flame length become shorter and the burning velocity is more rapid, but the particulate matters is higher. It is supposed that the air flow rate is high on Vessel. and then the combustion is Promoted in the surface area of the upstream zone. The future works plan to investigate the characteristics with an using of the mixing of IPA and PCBs

• 대한토목학회논문집
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• 제39권5호
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• pp.637-645
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• 2019

기후변화와 새로운 에너지정책의 변화등 대내외적인 환경정책의 변화로 도시특성과 에너지 사용량에 대한 파악이 필요하다. 기존에도 도시공간 구조를 활용한 연구는 누적되어왔지만 대부분 거시적으로 국가별, 수도권 위주, 대도시를 대상으로 했으며 경제성장이나 탄소배출과 에너지 사용량의 관계에 주목하였다. 본 연구는 이와는 달리 세부적으로 도시특성을 반영한 데이터를 바탕으로 기존의 교통에너지를 제외하고 가정과 산업 에너지 환경의 기반인 전기와 가스에너지 사용량과의 상관관계를 파악하고자 한다. 본 연구는 도시 토지이용과 제조업특성을 고려하여 도시 특성과 전기와 가스 에너지 사용량과의 연관성을 실증적으로 분석하였다. 통계적으로 유의미한 변수 중에서도 세대수와 면적의 도시 규모 특성과 지방세 징수액, 자동차 등록대수와 같은 경제적 특성, 도로와 시가화밀도등의 도시화 특성은 에너지사용량을 증가시키는 상관요인들로 도출되었다. 본 연구는 수도권 중심의 에너지 소비 분석에서 벗어나 부산광역도시권 지역사회 에너지 정책의 이론적 근거를 마련하는 데 도움이 되고자 하였다.