• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2000.11a
• /
• pp.107-108
• /
• 2000

PCBs (Polychlorinated Biphenyls)와 같은 미량 환경독성물질은 그 독성으로 인하여 지난 수 십년간 환경 분야에서 중요한 연구분야가 되어왔으며 이에 대한 연구의 중요성이 최근의 내분비계 교란물질의 심각성으로 더욱 부각되고 있다. 특히 이 분야의 연구에서는 실제 측정을 통한 자료가 국내의 경우 분석과 측정의 어려움으로 인하여 거의 전무하며, 더욱이 PCBs의 공간적인 분포 특성에 관한 연구는 PCBs에 대한 연구가 앞서 진행된 외국의 사례에서도 거의 찾아볼 수 없다 (Yucel, 1997, 김승규, 1999). (중략)

• Proceedings of the Korean Environmental Sciences Society Conference
• /
• 2002.05b
• /
• pp.70-74
• /
• 2002

해염농축계수는 해양기원인 $Cl^{-}$, $K^{+}$ 그리고 $Mg^{2+}$ 는 1.0 이상이고 10이하의 분포를 보였으나, $Ca^{2+}$ 와 ${SO_4}^{2-}$는 10 이상의 높은 값을 나타냈으며, ${So_4}^{2-}$는 상업지역, 공단지역, 주거지역 그리고 농업지역 순으로 조사되었다. 지역별 비해염 성분의 기여율은 $F^{-}$, $Ca^{2+}$ , ${So_4}^{2-}$, $K^{+}$, $Cl^{-}$ 그리고 $Mg^{2+}$ 의 순으로 나타났으며, 인위적 기원인 ${SO_4}^{2-}$은 상업지역(97.5%)이 가장 높은 해안지역 (71.5%)이 가장 낮게 나타났다. 해염입자의 기여율은 겨율 > 여름 > 가을 > 봄의 순으로서 겨울철 (47.4%)이 가장 높고, 봄철 (22.4%)이 가장 낮게 나타났다.

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2003.05b
• /
• pp.391-392
• /
• 2003

한전 원자력 환경기술원에서는 중ㆍ저준위 방사성폐기물 유리화 기술의 상용화 가능성을 입증하기 위한 유리화 실증설비를 건설하여 시험 중에 있으며 이 유리화 기술은 유도 가열식 저온로(Cold Crucible Melter, CCM)에 폐기물을 투입하는 기술로서 폐기물의 부피 축소 효과와 더불어 최종 고화물로 생성되는 폐기물의 침출율이 매우 낮은 장점을 지닌다. 이와 같은 유리화 공정은 기존의 소각처리에서와 같이 폐기물의 열적 산화과정에 의해 유해오염가스와 입자성 물질이 발생된다. 따라서 이를 처리하기 위해배기체 처리공정(Off Gas Treatment System, OGTS)을 설치하여 환경 배출기준(SO$_2$300ppm, NO$_2$ 200ppm, CO 600ppm, HCI 50ppm, 분진 100mg/Nm$^3$ 등)을 만족하도록 하였고 특히 입자성 물질은 후단 OGTS나 배관내 침적으로 인한 방사성 오염을 막기 위해 CCM 후단에서 효율적으로 제거되어야만 한다. (중략)

• Journal of Korean Society of Environmental Engineers
• /
• v.28 no.3
• /
• pp.249-256
• /
• 2006

Catalytic combustion of toluene was investigated on the Cu-Mn oxide catalysts prepared by the impregnation(Imp) and the deposition-precipitation(DP) methods. The mixing of copper and manganese has been found to enhance the activity of catalysts. It is then found that catalytic efficiency of the Cu-Mn oxide catalyst prepared by the DP method on combustion of toluene is much higher than that of the Cu-Mn oxide catalyst prepared by Imp method with the same chemical composition. The catalyst prepared by the deposition-precipitation method observed no change of toluene conversion at time on stream during 10 days and at the addition of water vapor. On the basis of catalyst characterization data, it has been suggested that the catalysts prepared by the DP method showed uniform distribution and smaller particle size on the surface of catalyst and then enhanced reduction capability of catalysts. Therefore, we think that the DP method leads on progressive capacity of catalyst and promotes stability of catalyst. It was also presumed that catalytic conversion of toluene on the Cu-Mn oxide catalyst depends on redox reaction and $Cu_{1.5}Mn_{1.5}O_4$ spinel phase acts as the major active sites of catalyst.

• Journal of the Korean Chemical Society
• /
• v.53 no.6
• /
• pp.761-764
• /
• 2009

Ag-Doped bioactive ceramic composites were prepared by colloidal silver solution. The physical properties of colloidal silver solution and Ag-Doped bioactive ceramic composites were characterized by Scanning electron microscopy(SEM), X-Ray Diffractometer(XRD) and Raman spectrophotometer respectively. According to XRD, we have identified that the chloride ion was chemically attached silver nano particles. SEM studies showed that silver chloride phases were homogeneously distributed on the Ag-Doped bioactive ceramic composites surface. Finally, we concluded that the silver chloride phase on the Ag-Doped bioactive ceramic composites surface was strongly prevent formation of Ag-hydroxyapatite.

• Particle and aerosol research
• /
• v.5 no.4
• /
• pp.179-188
• /
• 2009

The dry deposition fluxes of particulate polychlorinated biphenyls (PCBs) were measured along with their mass size distributions at Seoul and Incheon in fall in 1999. The dry deposition fluxes of PCBs were in the range of $16.7{\sim}62.2ng/m^2/day$. The ambient concentrations of particulate PCBs were in the range of 0.07 to $0.20ng/m^3$. Generally, the mass size distribution of particulate PCBs shows bi-modal distribution. The mass fraction of PCBs in the fine particle fraction ($D_p<2.1 {\mu}m$) was over than 55% of the total PCBs concentrations. It was found that Seoul and Incheon were not the major source of PCBs emissions in Korea. Based on the comparison with the measurement data in summer, 1999, it is likely that both the dry deposition fluxes and ambient particulate PCBs concentrations were not site-specific.

• 대한방사선방어학회:학술대회논문집
• /
• 2009.04a
• /
• pp.254-255
• /
• 2009

국내 경수로 원전의 경우, 원전의 효율적, 경제적 운영차원에서 장주기 운전으로 패턴을 바뀌면서 핵연료봉 표면상에 크러드(crud)의 침적량은 점점 증가하는 경향을 나타내고 있다. 이러한 경향은 원자로의 출력 제어와 직결되면서 이에 대한 문제 해결을 위한 대표성이 있는 시료의 채취와 재현성이 있는 부식 생성물의 측정이 요구되어져 왔다. 원자로 계통 내에서 부식생성물의 농도변화에 대한 평가, 특히 입자농도가 증가되어지면 축방향 출력편차(Axial Offset Anomaly, AOA)가 발생될 수 있는 위험에 노출되거나, 핵연료 교체를 위해 발전소 정지시(shut down) 부식생성물의 방출이 급격히 증가되는 것으로 나타났다. 특히 입자성을 띤 물질은 존재의 특성상 이들 물질에 대한 대표시료의 채취가 어려울 뿐 아니라 grab 채취로 인해, 분석결과에 대한 재현성이 낮으며 계통 선량율의 제어와 작업자 피폭관리에 많은 어려움이 뒤따르고 있어 선진 원전 운영국에서는 앞 다투어 대표시료를 채취 할 수 있는 capillary sampling 법이나 integrated sampling법을 적용해 오고 있다. 본 논문에서는 국내 경수로 원전에서 일반적으로 사용하고 있는 grab sampling 법에 대한 문제점 파악과 해외 원전에서 사용 중인 capillary sampling 법의 국내 적용 가능성에 대해 살펴보았다.

• Journal of Hydrogen and New Energy
• /
• v.19 no.4
• /
• pp.348-358
• /
• 2008

Reduction reactivity and carbon deposition characteristics of mass produced oxygen carrier particle(OCN-650) have been investigated by using hydrogen, methane, syngas, and natural gas as fuels. For all fuels, the maximum conversion and oxygen transfer capacity increased as the temperature increase. The reduction rate and the oxygen transfer rate increased as the temperature increase for methane. However, those values showed maximum at 900$^{\circ}C$ for hydrogen, syngas, and natural gas. To explain consistently the change of maximum conversion, reduction rate, oxygen transfer capacity, oxygen transfer rate and degree of carbon deposition for different fuels, new parameters such as reactive carbon contents and require oxygen per input gas were adopted.

• Journal of the Korean Applied Science and Technology
• /
• v.38 no.3
• /
• pp.662-668
• /
• 2021

The aim of the present study was to design ascorbyl glucoside (AG) loaded solid lipid nanoparticles (SLNs) to improve skin penetration of AG. AG loaded SLNs were prepared using double emulsion method. The prepared AG loaded SLNs investigated particle characteristics (particle size, polydispersity index, zeta potential, loading capacity). Skin penetration study was carried out using SkinEthic RHE as one of the reconstructed human epidermis models. The mean particle size and zeta potential of SLNs were 172.65 - 347.19 nm and -22.90 - -41.20 mV, respectively. The loading capacity of AG loaded SLNs demonstrated that loading efficiency and loading amount were ranged from 44.18% to 57.77% and 12.83% to 16.15%, respectively. The results of penetration showed that all SLNs enhanced the skin penetration of AG and the amount of AG from SLNs were approximately 3.7 - 7.4 times higher than that from AG solution. Therefore, AG loaded SLN might be a promising topical drug delivery system.

• Journal of the Korean earth science society
• /
• v.33 no.3
• /
• pp.280-293
• /
• 2012

In order to clarify the characteristics of dispersion of volcanic tephra emitted from the Mt. Baegdu with various eruption environment, numerical analysis were performed using numerical models, Weather Research and Forecast (WRF) and FLEXPART. Synoptic conditions at 12 October 2010 was adopted because the volcanic ash of Mt. Baegdu can reach the Korean peninsula and its dispersion pattern was compared with different Volcanic Explosivity Index (VEI) and particle size. Predominant size of falling out ash flowing in the peninsular is smaller than 0.5 mm and the ash large than the size is difficult to get in the peninsular due to the its weak ability of truculent diffusion. the difference of ash distribution with various VEI scenarios is not so much but number density of ash in the air is dramatically changed. Volcanic ash tends to be deposited easily in eastern coastal area such as Gangneung and Busan, because of the inflow of ash from East Sea and barrier effect of the Taeback mountains along the east coast of the Korean Peninsula. Accumulated amount of ash deposition can be increased in short period in several urban areas.