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        검색결과 2,366

        781.
        2010.03 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        The objective of this study was to estimate distribution of hazardous air pollutants and volatile organic compounds at diverse indoor areas in school. The indoor air samples were collected at 19 school in three different areas of southern Korea region from September to October 2009. The concentrations of PM-10 and formaldehyde in all sampling sites were below indoor air quality guideline of the Ministry of Education, Science and Technology. The CO2 level and TBC (total bacteria count) were higher than the guideline for 4 sites and 12 sites, respectively. The concentration of TVOC for 23 sites exceeded the guideline. Also, TVOC level of metropolitan sampling sites were somewhat higher than small and medium-size city sampling sites. The concentration of indoor air pollutants affected by various conditions such as season, region, and indoor/outdoor environment. This study result shows that concentration of several pollutants such as CO2, TBC, and TVOC were higher than the guideline for some sampling sites. Therefore, it is necessary to manage indoor air quality and establish effective emission reduction strategies regard for characteristics of each school.
        4,800원
        782.
        2010.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Due to the industrialization and urbanization, the transport of hazardous materials increases, which rises possibilities in occurring prospective accidents in terms of hazardous material transport as well. This study applied the model developed from the previous research to analyze the scale of damage areas from the accidents related to hazardous material accidents, as well as suggested a method to measure automatically the scale of accident including casualties and environmental damage based on the guideline which suggests the quantities of hazardous materials exposed from an accident and was defined in the study of standardization for hazardous material classification. A buffering analysis technique of Geographic Information System (GIS) was applied for that. To apply the model which evaluates the scale of population and exposure to environment on each link, rail network, zones, rail accident data, rail freight trips, and locations of rivers etc were complied as a database for GIS analysis. In conclusion, a method to measure damage areas by the types of hazardous materials was introduced using a Clip and a Special Join technique for overlay analysis.
        4,000원
        783.
        2010.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, the calibration characteristics of six new odorant VOCs along with two reference compound were evaluated based on GC-MS (SIM). For the proper evaluation of the GC/MS method, calibration of 7 VOCs were made both by the SPME and direct injection (DI). The minimum detection limit (MDL) of those VOC determined by SPME method fell in the range of 0.31∼0.38 ppb while those of DI from 6.18∼14.3 ppb. The analytical performance of our SPME/GC-MS method was compared against those tested previously by other study groups. Although more efforts are needed to establish the reliability of our SPME/GC-MS method, the method adapted in this study can be recommended as one of the standard methods for the analysis of the target VOCs in this study to settle formal experiment methods.
        4,000원
        784.
        2010.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Tetra-hydrothiophene ((CH₂)₄S) has an odor that is detectable at very low levels. For this reason, it was included as a component of dangerous gases to allow the detection of leaks by smell. A type of tetra-hydrothiophene gas CRM in the μmol/mol level was developed for the analysis of trace-level odorant gas in natural gas. The gas standards produced simultaneously in 3 bottles and examined by GC-FID were show with 0.12%, reproducibility of preparation and 0.05%, standard uncertainty due to weighing and purity. The concentration of tetra-hydrothiophene ((CH₂)₄S) was 10 µmol/mol level in the cylinder filled with methane, 1500 psi. And the variability of concentration for 1 years was about 0.03% due to the adsorption or instability of (CH₂)₄S. The relative expanded uncertainty of 1.0% (95% of confidence level, k=2) was assigned to the certified value of 10 μmol/mol level of(CH₂)₄S after quantitative evaluation on the purity, mixing, weighing, analysis, adsorption and stability of tetra-hydrothiophene gas.
        4,000원
        785.
        2010.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        단자엽 식물인 보리는 Agrobacterium을 이용한 형질 전환이 비교적 까다로운 편이다. 본 연구에서는 큰알1호, 내쌀보리, 올보리, 새찰쌀보리, 서둔찰보리,풍산찰쌀보 리의 유묘에 알칼리, 산화제, 환원제 등을 처리하여 화학 적 상처를 유발하였으며 이들에 감압진공을 이용한 Agrobacterium 형질전환을 실시한 후 GUS 유전자발현 을 분석하였다. 그 결과, 보리묘 생육을 일부 저하시킬 수 있는 농도의 화학물질 처리는 각기 다른 보리 품종의 형질전환율을 전반적으로 증대시킬 수 있는 것으로 판단 되었다. 화학물 중에서는 특히 hydrogen peroxide 처리 가 비교적 우수한 것으로 나타났다.
        4,000원
        786.
        2010.02 구독 인증기관 무료, 개인회원 유료
        We used a conventional activated sludge process to treat a paper wastewater, and then the effluent was treated with an ozone oxidation process as advanced process to remove non-degradable materials. It was found that the removal efficiency rates of the organic matter has been rapidly increased initially, and then it was almost constant after this period. The concentration of ozone should be recommended to maintain approximately 8.3 mg/L during this operation to keep the CODmn value below 100 mg/L and ozone contact time longer than 60 min.
        4,000원
        787.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목적: 최근 소프트 콘택트렌즈는 소재의 연구개발 뿐만 아니라 기능성의 연구개발도 함께 이루 지고 있다. 이에 본 연구는 Ag를 이용하여 항균성을 갖는 기능성 콘택트렌즈를 제조하였다. 방법: 기존 소프트 콘택트렌즈의 재료와 AgNO3을 혼합하여 교반한 후, 70℃에서 약 40분, 80℃에서 약 40분 건조하였다. 마지막으로 100℃에서 약 40분 열처리 공정을 거처 공중합하였다. 결과: 물리적 특성으로는 건조 후와 수화 후의 굴절률은 1.502~1.504와 1436~1.445, 함수율은 34.54%~39.03% 그리고 가시광선 투과율은 79.1%~83.8%를 나타내었다. 결론: 기존 소프트 콘택트렌즈의 소재와 은과의 중합을 통해 콘택트렌즈의 물리적 특성에도 부합되는 폴리머가 생성된 것으로 판단된다.
        4,000원
        788.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Different types magnesium hydroxide groups have been obtained using the hydrothermal precipitation technique from magnesium sulfate and calcium carbonate solution. The Mg atom coordinated around O atom of SO42- in another layer to form a multi-layer structure crystal. The influence of synthesis parameters on the morphological characteristics and size of magnesium hydroxide groups precipitated in aqueous were investigated such as different of additive and pH. Magnesium hydroxide groups were decomposed gradually and converted finally to MgO particles after heated in air temperature up to 1050℃. The particle size and it's distribution morphology, crystal phase and thermal behavior of the samples were characterized through XRD, SEM, EDS, and TG/DTA.
        4,000원
        789.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 기존의 중량법과 광산란법과는 원리와 기술이 다른 입도별 부유물질 측정용 분리막 모듈 및 장치를 개발하기 위한 원리를 수립하기 위한 기초 자료를 확립하고자 하였다. 이러한 목적을 위하여, 이산화규소 및 덱스트란(dextran), 카올린(kaolin), PEG (polyethylene glycol) 부유용액을 대상으로 유리섬유 여과지 GF/C와 GF/A를 분리막 모듈에 장착하여 여과시키면서, 디지털 압력계를 사용하여 막간압력차(TMP, Trans-membrane pressure) 변화를 측정하였다. 모사용액의 농도와 TMP 변화율 기울기의 상관관계식을 TMP 변화 실험 결과로부터 구하여, TMP 변화 기울기로부터 시료의 농도를 예측할 수 있도록 하였다.
        4,000원
        790.
        2009.12 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        Indoor air quality can be affected by indoor sources, ventilation, decay and outdoor levels. Although technologies exist to measure these factors, direct measurements are often difficult. Toluene and nitrogen dioxide (NO2) concentrations of residential indoor and outdoor were simultaneously measured and compared in 16 houses, using passive samplers during every 3 days for 60 days. Concentrations of toluene and NO2 were analyzed by gas chromatography and spectrophotometer, respectively. Using a mass balance model, penetration factor (ventilation rate divided by sum of ventilation rate and deposition constant) and source generation factor (source generation rate divided by sum of ventilation rate and deposition constant) were calculated by multiple indoor and outdoor measurements. The mean contributions of toluene of indoor and outdoor sources on residential indoor air quality were estimated to be 31.01% and 67.00%, respectively. On the other hand, mean contributions of NO2 were 58.93% and 41.06%, respectively. These results could be explained that contributions of indoor and outdoor air pollutants sources are different to residential indoor air concentrations. In conclusion, contributions of outdoor air and indoor sources affecting indoor air quality were effectively characterized using multiple indoor and outdoor measurements.
        4,000원
        792.
        2009.12 구독 인증기관 무료, 개인회원 유료
        현대인들에 있어 건강과 장수에 대한 관심이 증가하면서 식품의 생리활성 물질에 대한 발굴과 이용에 관한 연구는 지속적으로 발전하고 있다. 식품산업에서 상업적 가치를 갖 는 생리활성 물질은 주로 천연 식물체에서 유래되는 친유 성 화합물(lipophilic components)로서 생리활성 지질, 비 타민, 항균제, 항산화제 및 향미물질 등이 있다. 이들 친유 성 생리활성 물질들 중 기능성 식품시장에서 신상품 개발 의 대상이 되는 것들은 오메가-3 지방산, phytosterol, lycopene, lutein, β-carotene, coenzyme Q10, resveratrol, astaxanthin, quercetin 등이 있다. 이러한 친유성 생리활성 물질은 거의 물에 용해되지 않아 산업적 이용에 한계가 있 어 이를 해결하기 위한 기술개발이 요구되고 있다. 특히, 천연상태의 친유성 생리활성 물질을 추출 및 분리할 경우 빛, 온도 및 산소 등과 같은 외부 인자에 의하여 안정성이 크게 떨어지며, 동시에 체내 이용성과 흡수성이 낮아 활용 이 매우 제한적이다. 따라서 다양한 형태의 식품전달시스 템 개발에 있어 나노구조체 제조기술을 활용할 수 있으며, 생리활성 성분과 관계하는 특정 분자, 이화학적 및 생리학 적 특징 등이 중요한 인자로 고려되고 있다. 식품에 있어 상향식(bottom-up) 나노구조체 제조방법은 상기와 같은 생 리활성 물질의 품질, 안정성 및 이용성을 증진시킨 새로운 형태의 기능성 소재를 생산할 수 있는 기술로서 효율성, 경 제성 및 용이성 등과 같은 장점을 제공한다. 이에 본 발표 에서는 생리활성 물질을 함유하는 나노구조체 제조방법 및 응용분야에 대하여 논하기로 한다
        4,000원
        793.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Tantalum nitrides () have been developed to substitute the Cd based pigments for non-toxic red pigment. Various doping elements were doped to reduce the amount of high price Tantalum element used and preserve the red color tonality. Doping elements were added in the synthesizing process of precursor of amorphous tantalum oxides and then Tantalum nitrides doped with various elements were obtained by ammonolysis process. The average particle size of final nitrides with secondary phases was larger than the nitride without the secondary phases. Also secondary phases reduced the red color tonality of final products. On the other hand, final nitrides without secondary phase had orthorhombic crystal system and presented good red color. In other words, in the case of nitrides without secondary phases, doping elements made a solid solution of tantalum nitride. In this context, doping process controlled the ionic state of nitrides and the amount of oxygen/nitrogen in final nitrides affected the color tonality.
        4,000원
        794.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A Si-CuO-graphite composite was prepared by a mechanical alloying (MA) method. The Si-CuO composite has a mixture structure, where CuO is homogeneously dispersed in Si. Also, and phases were formed during MA and heat treatment. Graphite with the Si-CuO composite was mixed in the same mill for 30 minutes with weight ratio of Si-CuO composite and graphite as 1:1. The Si-CuO composite was homogeneously covered with graphite. SiC phase was not formed. Electrochemical tests of the composite have been investigated, and the first charge and discharge capacities of the material were about 870mAh/g and 660mAh/g, respectively. Those values are about 76% of the first cycle efficiency. The cycle life of the composite showed that the initial discharge capacity of 660 mAh/g could be maintained up to 92% after 20 cycles.
        4,000원
        795.
        2009.11 KCI 등재 구독 인증기관 무료, 개인회원 유료
        목이버섯으로부터 항혈전활성과 항혈소판응집활성을 지니는 물질을 추출하여 추출물의 혈행개선활성을 조사하였다. 건조 목이버섯을 0.1 N NaOH, methanol, ethanol 등의 용매를 사용하여 추출하여 각 추출물의 항혈전활성을 activated partial thromboplastin time, thrombin time과 prothrombin time 값으로 측정한 결과 methanol 용해성 분획이 각각 100, 124, 54 s로 조사한 분획 중에서 가장 높은 활성을 나타내었다. 활성 분획을 DEAE-Sepharose CL6B ion exchange column chromatography와 Sephacryl 400-HR gel permeation column chromatography로 정제하였으며 활성물질은 분자량이 150 kDa 이상인 다당류이며 mannose가 주요 구성당으로 되어 있는 xyloglucomannan의 복합다당체인 것으로 확인되었다. 정제된 다당류의 항혈전활성은 thrombin 활성을 저해하기 때문인 것으로 해석되었다.
        4,000원