Many countries of the world has been devoting a lot of effort to reduce carbon emission. In order to reduce carbon emission, the high efficiency engine has been studied in the automotive industry. Of these, the spread and research of the diesel engine in Europe center are active. However the combustion characteristic of diesel engines have disadvantages of much NOx and soot emissions. In this study, the optimum regeneration point of the forced regeneration type DPF(Diesel Particulate Filter) that was equipped in medium-duty diesel vehicles using a mechanical fuel injection system have studied. DPF that is applied to the medium-duty diesel vehicle has a bent inlet pipe. The flow distribution characteristics of DPF according to the influence of the bent pipe have investigated. The flow distribution characteristics of DPF according to variation of the engine operating condition is considered to be useful data In order to decide the optimum regeneration point.

이 연구의 목적은 2008년 5월 29일 우리나라에 영향을 미치는 황사를 예측하기 위해 WRF-Chem 모델 내 에어로졸 스킴과 광물성 먼지 옵션에 따른 미세먼지 농도 변화와 그에 따른 기상장의 민감도를 분석하는 것이다. 미세먼지의 인위적 배출량에 대해서는 0.5˚±0.5˚ RETRO 전구 배출량을, 광해리의 경우 Fast-J 광해리 스킴을, 그리고 황사 발생량을 추정하기 위해 RADM2 화학메커니즘 및 MADE/SORGAM 에어로졸 시나리오, MOSAIC 8 섹션 에어로졸 시나리오, 그리고 GOCART 먼지 침식 시나리오를 각각 적용하였다. 그 결과 RADM2 화학메커니즘 및 MADE/SORGAM 에어로졸 시나리오가 다른 시나리오들보다 우리나라 황사 먼지 농도와 배경 PM 농도를 더 높게 모사하였다. 그리고 이 시나리오와 서울의 각 대기질 측정망의 평균 PM10 농도와의 비교 결과, 상관계수는 0.67, 평균제곱근오차는 44μgm-3으로 나타났다. 또한 WRF-Chem 모델에서 상기 3가지 시나리오와 이들 시나리오가 없는 순수 기상에서의 온도, 풍속, 경계층 높이, 장파복사의 기상 민감도를 분석한 결과, 1,800-3,000 m 경계층 높이와 2-16ms-1 풍속 U 성분의 공간적 분포가 황사 먼지 발생의 공간적 분포와 유사하게 나타났다. 그리고 GOCART 먼지 침식 시나리오와 RADM2 화학메커니즘 및 MADE/SORGAM 에어로졸 시나리오는 황사 먼지 또는 에어로졸과 기상이 온라인으로 상호작용함으로써 지구장파복사가 더 낮게 모사되었다.

해수와 담수가 공존하는 시화호 상류 기수역에서 입자성유기물에 대한 조류의 영향을 평가하기 위하여, 2005년과 2006년 3월부터 11월까지 기수역내 7개 지점을 대상으로 입자성유기탄소 (particulate organic carbon; POC), 식물플랑크톤 색소(chlorophyll a; Chl-a), pheophytin a; Pheo-a)의 시공간적 변동과 상관관계를 분석하였다. 조사기간 동안 POC 농도는 1.0~76.6 mg L-1 (평균 7.4 mg L-1)의 범위로 봄에 높은 계절변화를 보였으며, 염분성층이 강하고 고탁도층이 형성되는 중류부에서 높은 값을 보였다. 살아있는 식물플랑크톤의 현존량의 지표로 이용되는 Chl-a 농도는 1.3~942.9 μg L-1 (평균 71.0 μg L-1) 범위로 매우 높은 값을 보였고, 4월에 중류부에 최고치를 보여 POC와 유사한 변동을 보였다. 한편 Pheo-a 농도는 1.4~1,545.5 μg L-1 (평균 59.9μg L-1)의 범위로, total Chl-a의 평균 44.2%로 죽거나 활성을 잃은 식물플랑크톤의 양이 많은 것으로 나타났다. POC 농도는 식물플랑크톤 색소와 강한 양의 상관(Chla (r=0.93), total Chl-a (r=0.88), ¤Pheo-a (r=0.81))을 보였는데, 이는 시화호 기수역에서 식물플랑크톤이 POC의 중요한 기원임을 시사한다. 한편 식물플랑크톤 색소와 POC와의 회귀식으로부터 POC/Chl-a 비(82.9)보다 POC/total Chl-a 비(35.9)가 하구에서 조사된 POC/Chla 비(40~60)에 더 유사한 것으로 나타났다. 그러므로 시화호 기수역과 같이 Pheo-a 농도가 높은 수역에서는 조류기원성 POC를 산정하거나 또는 수체의 POC 농도에 대한 식물플랑크톤의 기여도를 평가할 때 Chl-a 농도와 함께 Pheo-a 농도도 함께 고려할 필요가 있다.

The milling and particulate characteristics of Al alloy-Al2O3 powder mixtures for a reaction-bonded Al2O3 (RBAO) process were studied. A commercially available prealloyed Al powder with Zn, Mg, Cu and Cr alloying elements (7475 series) was mixed with a calcined sinter-active Al2O3 powder and then milled in centrifugal milling equipment for ~48 hrs. The Al alloy-Al2O3 powder mixtures after milling were characterized and evaluated in various ways to reveal their particulate characteristics during milling. The milling efficiency of the Al alloy increased with a longer milling time. Comminution of the Al alloy particles started with its elongation, showing a high aspect ratio. With a longer milling time, the elongated Al alloy particle changed in terms of its shape and size, becoming equiaxially fine particles. Regardless of the milling efficiency of the Al alloy particles, all of the Al alloy particles repeatedly experienced strong plastic deformation during milling, giving rise to higher density of surface defects, such as microcracks, and leading to higher residual microstress within the Al alloy particles. The chemical reactions, oxidation behavior and hydration behavior of the Al alloy particles and the hydrolysis characteristics of their reaction with the environment were also observed during the milling process and during the subsequent powder handling steps.

The aims of research of this paper are as follows; first of all, main contents of technical development are such as. 1. the burner system development for maximum efficiency of diesel particulate filter in low temperature emission gas, 2. the development of white fume reducing system by the second ejection in diesel, 3. the development of burner system for erasing of oxidation catalyzer of the most important role in diesel particulate filter, And the secondhand, expectation effect of this paper is such as. If the mass production of this development is successfully, this system is easy to applicable to small diesel vehicle stopping by low efficiency diesel particulate filter and is increased cost effective and adaptability by erasing oxidation catalyzer.

본 연구는 영산강하구역 입자물질 유입원의 시∙공간 적인 변화를 추정해 보고자 몽탄대교에서 영산강 하구둑 에 이르는 영산강하구역 세 정점에서 연 6회에 걸쳐 수 층 부유 물질의 탄소 및 질소 안정동위원소 비를 비교하 였다. 모든 정점에서 8월에 강우를 통한 외부기원 유기물 의 유입이 증가하였으며, 이 때 암모니아성 질소 및 규산 염의 유입 역시 함께 증가하였다. 탄소 안정동위원소 비 측정 결과 11월과 8월에 정점 별 유기물의 기원이 크게 차이 났으며, 안정동위원소 비 값을 이용하여 주요 유입 원 추정이 가능하였다. 11월에 모든 정점에서 질소 안정 동위원소 비가 무거운 값을 보였고, 인산염의 농도가 가 장 높게 나타났는데 이는 축산폐수 및 농경지를 통한 유 입이 영향을 준 것으로 판단된다. 또한 다른 정점에 비해 영산강 하구둑에서 모든 조사 기간 동안 비교적 높은 질 소 안정동위원소 비를 보였으며, 이를 통해 축산폐수 및 농경지를 통한 유기물 유입이 다른 정점에 비해 높을 것 으로 추정된다. 본 연구 결과를 통해 안정동위원소 비 분 석은 입자성유기물의 기원을 추정하는데 유용한 방법임 을 확인할 수 있었다.

This study was analyzed the characteristics of temperature distribution in DPF(Diesel Particulate Filter) equipped with partitioned electric heaters. Analysis parameters was used by variation to the length of pipe from exhaust manifold to inlet of filter. The temperature of the exhaust gas flowing into the DPF is related closely to the regeneration of filter. Due to space constraints, the DPF have inlet of bent pipe. The inlet of bent pipe induce the heterogeneous distribution of flow. The heterogeneous trapping of smoke is induced according to the heterogeneous distribution of flow. And the heterogeneous distribution of temperature in DPF is induced. In this study, without the use of assistive devices for even distribution of flow into DPF, the characteristics of temperature distribution in DPF were investigated according to the variation of the length of inlet pipe.

It was investigated the state information for the atmospheric conditions around Dang-jin industrial complex in Chungnam area may be polluted by the constructing steel industrial complex. It is aimed at characterization of the fine particulate matter and other air pollutants involved in it. Samples were collected two sites for monitoring point representing steel industrial complex and one site which is placed a remote and secluded from this industrial complex, and the concentration of PM10, heavy metals, and ion components were analyzed. As a results, PM10 average concentration was 64.6㎍/㎥ for the adjacent site before Hyundai Steel Company, 70.5㎍/㎥ in Bugok immigration settlement complex, and 56.5㎍/㎥ for Jeonggok-ri contrastive point. The distribution of heavy metals was detected as very low level for all sampling points. According to the result of statistical evaluation for the heavy metal analysis, variation range of Cu, Mn, Ca, Fe, and Mg were significant higher than others. Also, the seasonal concentration change trend of heavy metals was remarkable strong in spring and low in summer because of instable meteorological phenomena such as yellow dust happened in spring. Monthly changing pattern of a sulphate ion has kept unusually high level for summer period different other components. Relationship among PM10, heavy metal, and ion component were analyzed that high positive correlation coefficient for PM10 between Fe, Mn, Pb, Ca, Mg, Cd, Al in order and PM10 between NO3-, Cl- successively. Accordingly, it is suggested that a present atmospheric conditions of the surrounding area of Dang-jin steel industrial complex is considered to be good level. Although air pollutants in emissions from their complex were below the existing emission limit, it is regarded that the systematic and continuous research is needed to preserve clean air through atmospheric monitoring, source tracing research, and citizen's surveillance for the fine particulate matter.

In this paper, the effect of different land-use types on soil organic carbon (SOC) and Particulate Organic Carbon(POC) was studied by analyzing the soils in the meadow and conversing land of grassland to cropland in ecotones of agriculture and animal husbandry. It is shown t㏊t, compared with meadow, rotations of P/O and P/Cwill reduce SOC in 0-30㎝ soil layers by 47.54%-65.11% and 34.16-64.26% and POC by 16.90%-24.48% and 11.94%-20.29%, respectively. And SOC in meadow is more t㏊n in conversing land of grassland to cropland (P＜0.05). Conversing grassland to cropland in ecotones of agriculture and animal husbandry will decrease the contents of SOC and POC.

Recently Korean government introduced and strengthened the environmental polices to manage and enhance indoor air quality as a major assignment. As a result,“Indoor Air Quality Management Act”has been activated since May 2004. However, among many multi-usage facilities, the school environment has been excluded from such regulations. Thus, the purpose of this study is to survey indoor aerosol and CO2 concentrations in a university library which is one of major school facilities. Concentrations of PM10, PM2.5, and PM1 were intensively measured every 5 minute interval by means of a dust monitor with light-scattering principle. The mini-volume air samplers were used further to analyze inorganic elemental compositions of PM10 and to inter-compare with the dust monitor. Carbon dioxide was simultaneously monitored by a multi-gas monitor equipped with a non-dispersive infrared system. PM10 concentrations did not exceed the indoor air quality standard(150㎍/㎥) for all the sampling places. However, quick and steep increases of aerosol concentration were observed during the Asian Dust storm period. In addition, the concentration of PM10(74.1㎍/㎥) in the main university office was the highest among the entire sampling places. Although there was no specific pollution source in the library, the levels of aerosol and CO2 increased quickly due to various outdoor sources and human activities. The average CO2 concentration measured in three reading rooms, where ventilation was not fully operated, exceeded the indoor air quality standard of 1,000 ppm. Based on these case studies, effective management and reduction plans for indoor aerosol and CO2 were suggested for the large scale public buildings including university libraries.

The Ti-Ni alloy nanopowders were synthesized by a levitational gas condensation (LGC) by using a micron powder feeding system and their particulate properties were investigated by x-ray diffraction (XRD), transmission electron microscopy (TEM) and Brunauer-Emmett-Teller (BET) method. The starting Ti and Ni micron powders were incorporated into the micron powder feeding system. An ingot type of the Ti-Ni ahoy was used as a seed material for the levitation and evaporation reactions. The collected powders were finally passivated by oxidation. The x-ray diffraction experiments have shown that the synthesized powders were completely alloyed with Ti and Ni and comprised of two different cubic and monoclinic crystalline phases. The TEM results showed that the produced powders were very fine and uniform with a spherical particle size of 18 to 32nm. The typical thickness of a passivated oxide layer on the particle surface was about 2 to 3 nm. The specific surface area of the Ti-Ni alloy nanopowders was based on BET method.

Titanium alloys and Titanium alloy-based particulate composites were synthesized using the blended elemental P/M route. First, processing conditions such as the fabrication of master alloy powder were investigated. Ti-6Al-4V, Ti-5Al-2.5Fe, Ti-6Al-2Sn-4Zr-2Mo, IMI685, IMI829, Timetal 1100 and Timetal 62S, and Ti-6Al-2Sn-4Zr-2Mo/ 10%TiB and Timetal 62S/10%TiB were then synthesized using the optimal processing conditions obtained. The microstructures and mechanical properties such as tensile strength and high cycle fatigue strength were evaluated.

Warm compaction powder metallurgy was used to produce a Ti3SiC2 particulate reinforced Cu matrix composite. Fabrication parameters and warm compaction behaviors of Cu powder were studied. Based on the optimized fabrication parameters a Cu-based electrical contact material was prepared. Results showed that in expend of some electrical conductivity, addition of Ti3SiC2 particulate increased the hardness, wear resistivity and anti-friction ability of the sintered Cu-base material.

원자력연구소 핫셀의 구조와 오염특성이 조사되었다. SEM 측정결과 핫셀 내부에 부착된 고방사능 분진의 크기는 이었다. 사이클론의 최적 Vortex finder의 길이는 49 mm이고, 모의입자 유입속도는 15m/sec가 적합했다. 이때 의 포집효율은 약 85%였다. 모의 입자 유입속도가 15m/sec보다 빠를 때, 포집효율의 증가율은 크지 않았다. 유입가스의 온도가 증가할 때, 포집효율은 약간 감소했다. Vortex finder의 길이가 증가할수록 사이클론내의 압력강하는 커졌다. Cut size diameter는 Reynolds number의 증가와 함께 감소했다. 측정된 Reynolds number에 근거하면, 사이클론 내부는 난류이고 이 난류는 사이클론 내의 압력강하에 원인이 된다고 사료된다. 는 Re 값의 증가와 함께 감소하고, Re의 값이 커질 때에서 일정한 값에 수렴했다. 즉, 6000-8000의 Re에서 는 약 0.045를 나타냈다.

This study was performed to investigate indoor air quality and to characterize the concentration of particulate matters followed by human activities in preschool classrooms. Concentrations of PM10, PM2.5, and PM1 were measured every 5-minute intervals by means of a dust monitor adopting the principle of light scattering. Two mini-volume air samplers were used further to measure the I/O concentration ratio of PM10 and to calibrate the dust monitor since the photometric method often exaggerates the mass of fine particles. The calibration factor in the study environment was determined as 0.64. In the preschool classrooms, the ranges of average indoor PM10, PM2.5, and PM1 concentrations were 51.5~117.6, 21.5~98.4, and 16.2~84.5 ㎍/ ㎥, respectively, while that of I/O concentration ratio was 0.8~1.3. Based on correlation analysis among various environmental parameters, PM1 was slightly correlated with humidity (r=0.416, p<0.01). However, outdoor PM10 was strongly related with indoor PM2.5 (r=0.95, p<0.01), with PM1 (r=0.94, p<0.01), and with PM10 (r=0.84, p<0.01). The trend of PM2.5 and PM1 concentrations appeared to be very similar unlike the case of PM10. Since the elevated coarse particle concentration (2.5㎛<dp<10㎛) and the average PM2.5/PM10 ratio were highly dependent on classroom activities, the parameter of PM2.5/PM10 ratio was intensively studied with 7 different indoor activities in the preschool classrooms.

System L amino acid transporter is a major route for providing living cells with neutral amino acids including several essential amino acids. To elucidate the expression pattern of L-type amino acid transporter 1 (LAT1) in the bone formation process, the expressions of LAT1 and its subunit 4F2 heavy chain (4F2hc) were investigated in the healing process after the implantation of bone graft materials in the calvarial osseous defected rats. Circular calvarial defects (1 cm in diameter) were made midparietally. The rats were divided into 4 groups of 1 control group and 3 experimental groups. In the control group, the defect was only covered with soft tissue flap. In the experimental groups, they were filled with human particulate dentin (particulate dentin group), with plaster of Paris (plaster of Paris group) and with the mixture of human particulate dentin and plaster of Paris with ratio of 2 : 1 by weight (mixture group). The rats were sacrificed at the 1, 2, 4 and 8 weeks after operation and the RT-PCR analysis and immunohistochemical analysis were performed. In the RT-PCR analysis, the mRNAs of LAT1 and 4F2hc were strongly detected in all 4 groups. In the immunohistochemical analysis, at 1 week after operation, the LAT1 protein and its subunit 4F2hc protein were mainly expressed in the osteoblasts, osteocytes and interstitial tissues of the around the defect and inner part of newly forming bone in all 4 groups. The expressions of LAT1 and 4F2hc proteins were decreased at 2 and 4 weeks after operation. The LAT1 and 4F2hc proteins were scarcely expressed at 8 weeks after operation in all 4 groups. These results suggest that the LAT1 and its subunit 4F2hc highly expressed at the early stage of new bone formation and may have an important role in providing cells with neutral amino acids including several essential amino acids at that stage.

A ventilation system comprising a dielectric barrier discharger and UV‐TiO2 photocatalyst filters was designed and tested for simultaneous removal of gaseous and particulate contaminants in a test chamber. The DBD was used as the 1st stage of ESP for particle charging and gas decomposition. Charged particles were collected in the 2nd stage of ESP by an applied DC electric field. The UV‐TiO2 photocatalyst filters were used for decomposing gaseous species including O3 which was inherently produced by the DBD. Particle removal efficiencies based on mass and number were approximately 83.0% and 88.8%, respectively, after the ventilation system was operating for 5 hours. HCHO removal efficiency was approximately 100% for 1∼5ppm of upstream concentration condition. TVOC removal efficiency was 99.0% and 99.6% for 1 ppm and 5 ppm of upstream concentration conditions, respectively.