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In-situ 법에 의한 폴리우레탄/기능화 된 그래핀 나노복합체의 합성에 관한 연구 (A Study on Synthesis of Polyurethane/Functionalized Graphene Nanocomposites by In-situ Intercalation Method)

  • 황수옥;이병환;조을룡
    • Elastomers and Composites
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    • 제47권3호
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    • pp.238-245
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    • 2012
  • 천연 흑연으로부터 Graphene oxide(GO)를 합성한 후 diisocyanatodicyclohexylmethane($H_{12}MDI$)를 이용하여 GO의 표면을 기능화하였고, hydrazine monohydrate에 의한 환원을 통해 isocyanate-graphene sheet(i-RGO)를 얻었다. 폴리우레탄과 적합한 나노복합체를 형성하기 위하여 GO, i-RGO, 천연흑연 및 열적환원된 graphene을 서로 비교분석하였으며, i-RGO가 가장 적합한 나노충전제로 선정되었다. 선정된 i-RGO의 함량에 따른 폴리우레탄의 물성 향상을 확인하기 위하여 충전제의 함량을 다르게 하여 PU/i-RGO 나노복합체를 합성하였다. 물성 평가에서, i-RGO의 함량이 증가할수록 열적 안정성, 경도 및 접촉각(발수력)이 향상되었는데, 이는 i-RGO의 물성 특성 및 가교점 작용에 기인한 것으로 판단되었다. 다만, 인장강도와 신장률의 경우 함량이 4 wt%를 넘어갈 경우 오히려 물성이 감소하는 것을 확인할 수 있었는데, 이는 과량의 가교점 형성이 원인인 것으로 해석되었다.

Synthesis of oleyl-4[131I]-iodobenzoate for long-term cell trafficking

  • Jeon, Hak Rim;Lee, Woonghee;Oh, Jieun;Lee, Yong Jin;Yoo, Jeongsoo
    • 대한방사성의약품학회지
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    • 제4권2호
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    • pp.45-50
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    • 2018
  • Great efforts are currently devoted to the development of new approaches for the labeling of cells using appropriate radionuclides. While fluoride-18 and copper-64 have been extensively studied as short-term and intermediate-term trafficking agents, iodide was studied less intensely. Here, we report a new cell labeling agent labeled with $^{131}I$, $[^{131}I]$oleyl-4-iodobenzoate ($[^{131}I]$OIB) for long-term cell trafficking. A precursor of $[^{131}I]$OIB was obtained in two steps, with the yield of 35%. The radiochemical yield of $[^{131}I]$OIB was over 50%. While $[^{131}I]$OIB could label different cells, L6 cells showed the highest cell-labeling efficiency. The $[^{131}I]$OIB-labeled L6 cells were imprinted into a rat heart, and then monitored noninvasively for 2 weeks by gamma camera imaging. We conclude that $[^{131}I]$OIB is a good candidate molecule for a long-term cell trafficking agent.

초.중.고등학교 시설의 급수 사용량에 대한 연구 (A Study on Typical Rates of Water-use for Primary School, Middle School and High School Facilities)

  • 김규생
    • 설비공학논문집
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    • 제20권12호
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    • pp.802-807
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    • 2008
  • A Study on Typical Rates of Water-use for School Facilities has been carried out in this work. Water supply system is given much weight in school facilities. Therefore, it set up a basis efficiency using of water sources to calculate typical rates of water use. The results are summarized as follows; 1) On the whole, typical rates of water-use was founded out 15 L/stu. d in pirmary school, 10 L/stu. d in middle school and 30 L/stu. d in high school smaller than the existing it. It was rate of water-use change as season and Max. Rates of water-use was July. 2) I deem that school hours are 5 hour's in primary school, 7 hour's in middle school and 8 hour's in high school. It the concept of 1 hour that is lesson time 40 minutes and resting time 10 minutes in primary school, lesson time 45 minutes and resting time 10 minutes in middle school and lesson time 50 minutes and resting time 10 minutes in high school. 3) It is desired that we calculate the volume of pump and water tank throughout this concept and the size of water tank should be 1.5 times with taking peak load into consideration by this study on typical rate of water-use. 4) The amount of using water increases in gradually and I consider the life cycle of facilities is more than 10 years. As a result, I can forecast that the size will be insufficiency but I deem that if we devise a plan about parallel pumping on water tank space, we can cope with it. Also, it is expected that we can cut back the transport energy by controlling pump volume.

초.중.고등학교 시설의 급수 사용량에 대한 연구 (A Study on Typical Rates of Water-use for Primary School, Middle School and High School Facilities)

  • 김규생
    • 대한설비공학회:학술대회논문집
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    • 대한설비공학회 2007년도 동계학술발표대회 논문집
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    • pp.510-515
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    • 2007
  • A Study on Typical Rates of Water-use for School Facilities has been carried out in this work. Water supply system is given much weight in school facilities. Therefore, it set up a basis efficiency using of water sources to calculate typical rates of water use. The results are summarized as follows ; 1) On the whole, typical rates of water-use was founded out 15 L / stu. d in pirmary school, 10 L / stu. d in middle school and 30L / stu. d in high school smaller than the existing it. It was rate of water-use change as season and Max. Rates of water-use was July. 2) I deem that school hours are 5 hour's in primary school, 7 hour's in middle school and 8 hour's in high school. It the concept of 1 hour that is lesson time 40 minutes and resting time 10 minutes in primary school, lesson time 45 minutes and resting time 10 minutes in middle school and lesson time 50 minutes and resting time 10 minutes in high school. 3) It is desired that we calculate the volume of pump and water tank throughout this concept and the size of water tank should be 1.5 times with taking pick load into consideration by this study on typical rate of water-use. 4) The amount of using water increases in gradually and I consider the life cycle of facilities is more than 10 years. As a result, I can forecast that the size will be insufficiency but I deem that if we devise a plan about parallel pumping on water tank space, we can cope with it. Also, it is expected that we can cut back the transport energy by controlling pump volume.

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고등학교 화학 Ⅰ교과서의 STS 교육 내용 및 구성 방식 개선 방안 (Improvement Schemes of STS Contents and Structure of the High School Chemistry Ⅰ Textbooks to be developed by the 7th Curriculum)

  • 홍미영
    • 대한화학회지
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    • 제45권5호
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    • pp.491-499
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    • 2001
  • 본 연구에서는 제6차 교육과정에 의거하여 개발되어 현재 고등학교에서 사용중인 화학 I교과서에서 과학-기술-사회(Science, Technology and Society, 이하 STS) 내용 및 활동 유형, 제시 방식 등을 검토하고, 이 결과을 외국의 대표적인 고등학생용 STS 자료를 분석 한 결과와 비교하여, 장차 제7차 교육과정에 의거하여 개발될 고등학교 화학 I교과서에서 적절한 STS 내용 및 구성 방식을 제시하였다. 본 연구에서는 현행 고등학교 화학 I교과서 중 임의로 5종을 선택하여 STS내용, STS 교수 학습 활동 유형, STS 내용 제시 양식, STS 내용의 포함 정도를 기준으로 하여 분석하였다. 그리고, 외국의 STS 프로그램 중에서 Chemistry in the Community, Science and Technology in Society, Chemistry; The Salter's Approach를 선택하여 구성 방식의 특징, 교재에서 다루고 있는 학습 주제 및 우리 나라 화학 I교육과정과의 관련성을 분석하였다. 연구결과에서 학습 내용적인 살펴보면, 제 6차 교육과정에 의거하여 개발된 화학 I교과서에서는 주로 '사회적 문제','과학의 응용성', '과학의 다차원성'만 다루고 있고, '과학에 관련된 직업에 대한 인식'과 '실제 문제에 대한 협동 작업'과 관련된 내용은 전혀 없으므로 다양한 측면의 STS 내용을 다루고 있지 않다고 볼 수 있었다. 반면, 외국 교재에서는 과학${\cdot}$기술과 관련된 직업을 소개하는 난이 독립적으로 되어 있거나 실제로 의사 결정을 해야 하는 내용 등 다양한 내용을 다루고 있었다. 활동 유형을 살펴보면, 지역에 대한 사례 조사, 역할 놀이, 다양한 의사 결정 활동 등 다양한 학생 활동을 제시하고 있는 외국 STS 교재에 비하여 우리나라 화학 I교과서는 설명 위주였으며, 조사와 토론 활동이 대부분이므로, 학생 활동이 상당히 빈약하다고 볼 수 있었다. 그러나, 중학교 과학 교과서에 비하여 STS 내용 포함 비율은 높아졌으며, 책마다 STS에 대하여 따로 소개하고 있어서 우리 나라의 화학 교과서가 STS적인 성격을 띠려고 시도하고 있음을 알 수 있었다. 이러한 결과들을 바탕으로 하여, 우리 나라 제 7차 교육과정에 의거한 화학 I교과서에서의 STS 내용 및 구성 방식을 제안하였다.

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갑상선암 환자에서 방사성옥소($^{131}I$) 치료로 인한 림프구의 자매염색분체교환(SCE) 빈도증가 (Increased Frequency of Sister Chromatid Exchanges After $^{131}I$ Therapy in Lymphocytes of Thyroid Cancer Patients)

  • 최근희;범희승;김광윤;김지열;윤정한;제갈영종;김재민
    • 대한핵의학회지
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    • 제27권1호
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    • pp.118-122
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    • 1993
  • 전이성 분화갑상선암을 치료할 목적으로 사용된 $^{131}I$에 의한 염색체 손상여부를 검정하기 위하여 치료 전후의 자매염색분체교환(SCE)의 빈도 및 말초혈액의 백혈구수를 정상대조군과 환자군에서 조사하였다. 1) 정상인으로 설정한 대조군에 있어서의 자매염색분체교환 빈도수가 $3.8{\pm}0.4$인데 비하여 $^{131}I$ 투여전의 SCE 빈도가 $4.2{\pm}0.7$으로 차이를 보이지 않았다(p=0.17). 2) $^{131}I$ 투여후 2일째 SCE 빈도는 $7.9{\pm}0.8$으로 치료전에 비해 유의하게 증가하였으며 (p<0.001), 9일째에는 $6.4{\pm}0.6$으로 2일째에 비해서는 유의하게 감소하였으나(p=0.002), 치료전에 비해서는 아직도 유의하게 높았다 (P<0.001). 3) 같은 기간동안 백혈구의 수는 유의한 변화를 보이지 않았다. 결과적으로, $^{131}I$ 치료후 염색분체의 손상은 일어나며, 서서히 회복되나 1주일 이내에는 완전한 회복을 보이지 않음을 알 수 있었다.

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연년익수고본단(延年益壽固本丹)의 육모효능(育毛效能)에 대한 면역조직화학적 연구 (Immunohistochemical Study on Hair Growth Promoting Effect of Yonnyuniksoogobon-dan)

  • 정춘근;심은섭;이창열;김범회;김성준;강희;손낙원
    • 대한한의학회지
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    • 제31권2호
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    • pp.48-63
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    • 2010
  • Objectives: Yonnyuniksoogobon-dan (Yan Nian Yi Shou Gu Ben Dan 延年益壽固本丹) is composed of 11 herbs (Polygoni Mutiflori Radix, Lycii Radicis Cortex, Polia, Rehmanniae Radix, Rehmanniae Radix Preparat, Asparagi Radix, Liriopis Tuber, Lycii Fructus, Acori Graminei Rhizoma, Angelicae Acutiloba Radix, and Pini Folium) based on Yonryunggobon-dan (Yan Ling Gu Ben Dan 延齡固本丹) and Yonnyuniksoobulrho-dan (Yan Nian Yi Shou Bu Lao Dan 延年益壽不老丹). This study evaluated hair growth promoting effect of Yonnyuniksoogobon-dan on the shaved C57BL/6 mice. Methods: Yonnyuniksoogobon-dan was treated by oral administration (Sample I) and oral administration plus skin application (Sample II) once a day for 12 days. Hair regrowth was photographically and histologically determined during the experimental period. Hair growth cycle related factors (EGF, TGF-${\beta}1$) and vascular factors (VEGF, iNOS) were also determined with immunohistochemistry. Results: 1. On gross observation of hair regrowth, Sample I and Sample II groups demonstrated acceleration of hair regrowth. 2. The hair regrowth index of the Sample I group increased significantly from 7 days (P<0.05) to 12 days (P<0.01) after the shave while that of the Sample II group significantly increased at 12 days (P<0.05). 3. On histological observation, both Sample I and Sample II groups demonstrated histological improvement and increases of number and diameter of the hair follicles. 4. EGF expressions on the root sheath of hair follicles were up-regulated in both Sample I and Sample II groups. 5. TGF-${\beta}1$ expressions on the root sheath of hair follicles were not regulated in Sample I or Sample II groups. 6. VEGF expressions in the surrounding tissues of hair follicles were up-regulated in both Sample I and Sample II groups. 7. iNOS expressions in the surrounding tissues of hair follicles were down-regulated in both Sample I and Sample II groups. Conclusions: These results suggest that Yonnyuniksoogobon-dan has hair growth-promoting activity and these effects relate to up-regulations of EGF and VEFG expressions and down-regulations of TGF-${\beta}1$ and iNOS expressions on hair roots.

고온환경하에서 탄소강의 피로균열진전 특성 (A Study on the Fatigue Crack Grouth Charactionistic of carbon Steel in High Temperature Environment)

  • 이종형;최성대;양성현;김영문
    • 한국산업융합학회 논문집
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    • 제7권4호
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    • pp.399-405
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    • 2004
  • Currently, the use of carbon steel in a high temperature environment, such atomic reactor, increases. Test piece was heated in electric furnace and the prescribed temperature was controlled within ${\pm}1^{\circ}C$. Debris that falls apart from cracked section due to friction is accumulated inside. Then, as it causes fretting corrosion (formation of oxide layer), it contributes to crack closure.

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학교시설물의 친환경을 위한 건축계획 방향과 단계별 적용 제안 연구 (A Study on the Proposal for the Direction of the Architectural Planning for Environment-Friendly of the School Establishment and its Sequential Application)

  • 이용환;한동욱
    • 교육녹색환경연구
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    • 제9권3호
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    • pp.59-67
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    • 2010
  • Architectural design for school can be completed well when the environment-friendly elements are satisfied. In other words, the environment-freindly element could be most important idea for school planning, and one should have this direction for each element as a design goal. In this study, I defined the "environment-friendly" as the environment for nature and human. I examined what could satisfy those and would be its principles. I set up the criteria to satisfy each priciple. Most important factor to keep the relation between nature and human would be reducing carbon dioxide emissions, and a green belt would absorb it. Therefore, I think that there would be effective possibility when suitable conditions are applied in phases. Every school can have comfort as environment-friendly facility, at the same time, contribute to nature. Also, students can learn and study nature, and perform a duty as human.