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        검색결과 13

        1.
        2022.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 전기투석과 용매추출을 융합한 희유금속 회수 공정에서 분리막과 음이온교환막의 개질을 통해 유기상 과 수상에 대한 분리막의 낮은 젖음성 및 AEM을 통한 수소이온 투과로 인한 금속이온의 회수 효율 감소를 개선하였다. 구체 적으로, 분리막 표면 중 한면은 polydopamine (PDA) 통한 친수성 개질, 다른 면은 SiO2 또는 graphene oxide를 통한 친유성 개질을 함으로써 분리막의 젖음성을 개선하였다. 또한, 음이온교환막의 표면을 polyethyleneimine, PDA, poly(vinylidene fluoride) 등을 이용, 개질해 수분 흡수(Water uptake) 감소 및 기공구조 변화를 통해 수소이온 수송을 억제해 수소이온 투과를 억 제할 수 있다. 개질된 막 표면 형상과 화학적 특성 및 조성은 주사전자현미경과 푸리에변환 적외선 분광법을 통해 확인되었 고, 이를 구리 이온 회수 시스템에 적용해 향상된 추출 및 탈거 효율과 수소이온 수송 억제능을 확인하였다.
        4,000원
        2.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        고용량 배터리에 대한 요구가 증가에 따라 기존 음극재보다 높은 용량(3,860 mAh/g)과 낮은 전기화학적 전위(– 3.040 V)를 갖는 리튬 금속 기반 음극재에 대한 연구가 활발하게 이루어지고 있다. 본 연구에서는 수열 합성을 통해 제작된 아나타제(anatase) 타입의 TiO2 나노 입자 기반한 PVdF-HFP/TiO2 복합체를 리튬 금속 음극의 계면 보호층으로 적용하였다. 결정구조 및 형상 분석을 통해 유/무기-리튬 나노복합체 박막의 형성을 확인하였다. 또한, 전지화학 테스트(사이클 테스트 및 전압 프로파일)를 통해 리튬 금속 음극의 전기화학 성능은 복합체 보호막이 TiO2 10 wt%, 코팅 두께 1.1 μm의 조건에서 가장 개선된 전기화학적 성능(콜롱 효율 유지: 77 사이클 동안 90% 이상) 발현을 확인하였다. 이를 통해, 처리하지 않은 리튬 전극 대비 본 보호층에 의한 리튬 금속 음극의 성능 안정화/개선 효과가 검증되었다.
        4,000원
        3.
        2010.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Grossly, a lot of soft white nodules, 0.5~1.5 cm in diameter, were randomly scattered in liver of a slaughtered Korean Native Cattle. The surface of liver was roughened by those nodules. Histopathologically the nodules were consisted of numerous mature blood vessels, which had variable size and wall thickness, and which were encircled by much connective tissue. Masson's trichrome stain clearly revealed the proliferated blood vessels and perivascular stroma and, immunohistochemical staining revealed that endothelial cells of proliferated blood vessels were positive for Von Willebrand Factor. Based on gross and histopathological lesions, and immunohistochemical staining, the case was confirmed as hepatic vascular hamartoma and it is the first case report in Korea, as far as we know.
        3,000원
        5.
        2008.06 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        In this study, we attempted to estimate the association between asthma oriented by indoor air sources and personal exposure by comparing the case (asthma-patient) and control (non-asthma-patient) groups. We selected 27 participants who showed positive response on lung function and methacholin provocation test. We performed environmental survey with 15 and 10 cases during May and June 2007, respectively. There was no significant difference between the case and control groups in the level of formaldehyde and TBC (Total Bacterial Count). In the dust allergen test, the case concentration was higher than the control's, without signifiant difference. In the personal exposure assessment of VOCs using OVM (Organic Vapor Monitor) badge, the case concentrations of Benzene, Toluene, and Ethylbenzene were higher than the control's, but there was no significant difference. The personal exposure of Xylene case study was significantly higher than the control's
        4,900원
        6.
        2008.03 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        This study was followed up asthma incidence rate in primary schools indoor air quality. To investigate the history and prevalence rate of allergic diseases(asthma, atopy dermatitis, allergic rhinitis and conjunctivitis), the standardized and generally used International Study of Asthma and Allergies in Childhood(ISAAC) questionnaire was used to conduct the symptom survey for all participating subjects. The concentrations of major indoor air pollutants(dust mite allergen, aldehydes , VOCs, TBC, phthalate) were observed from April to May 2007. Sampling was undertaken at 19 primary schools. The sampling sites of air pollutants are classroom’s indoor and hallway. Dust mite allergen part it was detected from the case classroom and infirmary. The exposure quality of aldehyde and the place pollution level was indoor>outdoor>hallway, which whole is disease incidence rate high group appears more highly the low group than. The partially result of formaldehy and VOCs, the concentration of high environmental disease incidence rate showed also high. However, house dust allergen, TBC and phthalate measurement school was not the effect where the comparison of difference.
        4,800원
        7.
        2008.03 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        This study was performed to investigate airborne volatile organic compounds(VOCs), formaldehyde, respiratory particulate for concentration in primary schools. The concentrations of major indoor air pollutants(VOCs , benzene, toluene, ethylbenzene, xylene, styrene, formaldehyde, PM-10) were observed from November to December 2006. Sampling was undertaken at 81 primary schools. The sampling sites of air pollutants are classroom and hallway. VOCs with distribution of most of general environmental contamination material will be able to confirm that it shows the log-normal distribution which is similar exposure distribution. The exposure quality of VOCs and the place pollution level was indoor> hallway>outdoor, which whole is located in the metropolis and the industrial areas is higher than farm village area. It tried to observe the I/O ratio, it appeared highly from the interior of the material of most. The mean concentrations of formaldehyde, respiratory particulate were 22.07㎍/㎥, 88.06㎍/㎥ respectively. Indoor and outdoor ratios(I/O) of formaldehyde and respiratory particulate were 3.6 and 1.4, respectively. The concentration of respiratory particulate is 27.2% higher than guideline for school hygiene(100㎍/㎥). From the comparison in the construction year, the highest concentration of formaldehyde is showed under one year. However, as time passed by the concentrations of formaldehyde become lower.
        4,500원
        8.
        2008.03 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        This study was carried out to assess the improvement of treatment by the house-plant. For the purpose of this study, 17 asthma-patients residing in Seoul were selected as participants during January to March 2007. We measured VOCs and conducted clinical survey during April to September 2007. In this study, 6 species of houseplants known to be eco-friendly were investigated for the health effect along with 12 other plants. The research focused on peak expiratory flow rate(PEFR) and disease specific quality of life. When the results were compared to the non-intervention households, the intervention households had reduced levels of acetaldehyde, benzene, ethylbenzene, xylene and styrene. The reduction rate estimated from this comparative study was statistically significant(p<0.05). There was however no association between the intervention and the estimated PEFR between morning and evening data in asthma-patients.
        4,300원
        9.
        2007.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 투과증발법을 이용하여 수용액 중 미량의 목련 향 성분을 농축하는 방법으로, PVDF/PDMS 복합막을 제조하여 지지막의 구조와 활성층의 두께에 따른 분리능의 변화를 살펴보았다. PVDF 지지막은 제막조건인 응고액의 온도가 감소하고 고분자 농도가 증가함에 따라 지지층에서의 표면공극률과 기공의 직경이 감소함을 순수투과실험을 통해서 간접적으로 확인하였고, 복합막에 대한 지지막 구조의 영향을 투과 mechanism식에 적용하여 해석하였다. 또한 PDMS의 두께가 증가됨에 따라 선택도가 증가하는 결과를 통해서, 활성층에서의 물질전달을 Fick's law에 의하여 설명하는데 제한이 있음을 알 수 있었다.
        4,000원
        10.
        2007.03 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        The objective of the present study was to assess the health effect of houseplant. we selected 22 households of newly-built apartments and 17 asthma patients. Before intervention in the households, we conducted clinical survey investigations during April and October, 2006. In this study, 6 species of houseplants known to be eco-friendly and 14 other plants were recruited. While the clinical research items were lung function, erythrocyte sedimentation rate(ESR), white blood cell count(WBC), total eosinophil count(TEC) and total-immunoglobulin E(T-IgE). There was no association between the intervention and the estimated inflammation reaction and allergic reaction. However, peak expiratory flow rate(PEFR) of evening data were positive effect in the intervention asthma-patients households compared with the nonintervention.
        4,500원
        11.
        2006.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 투과증발법을 이용하여 수용액 중 미량의 감귤 향 성분을 농축하는 방법으로, 4종류의 실록산계 고분자 복합막을 이용하여 막 종류와 구조에 따른 투과 특성을 살펴보았다. 또한 최적의 막을 선정하여 공급액의 온도와 농도, 순환 유속에 따른 투과 특성을 살펴보고, 이를 resistance-in series model을 이용하여 해석하였다. 4종류의 실록산계 고분자 복합막을 통한 감귤 essence aroma 모델액의 투과 실험에서 지지층이 polyvinylidene fluoride (PVDF)이고 활성층이 polyoctylmethyl siloxane (POMS)인 막이 가장 높은 향 성분 플럭스와 농축계수 값을 나타내었으며, 공급액의 온도와 농도, 순환유속을 변화시키며 투과 실험을 하였다. 그 결과 공급액의 온도와 농도가 증가됨에 따라 향성분의 플럭스는 증가하고 농축계수 값은 감소하였으며 순환유속이 증가됨에 따라 향성분의 플럭스와 농축계수 값 모두 증가하였다.
        4,000원