• 제목/요약/키워드: enrichment

검색결과 1,855건 처리시간 0.033초

Polycarbonate/Metal Salt 막의 산소분리특성에 미치는 비용매와 금속염 농도의 영향 (Effect of Nonsolvent and Metal Salt Concentration on Oxygen Separation Performances of Polycarbonate/Metal Salt Membrane)

  • 서상훈;이우태
    • 한국산업융합학회 논문집
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    • 제4권1호
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    • pp.61-69
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    • 2001
  • Polycarbonate(PC) membranes for oxygen enrichment from air were prepared by the wet phase inversion method. In order to improve oxygen separation performances of the PC membrane, the effect of the added ethanol(nonsolvent) and $CuCl_2$(metal salt) concentration in the casting solution on morphology, oxygen permeability ami $O_2/N_2$ separation factor of the membrane was studied. In addition, tensile strength and elongation at break of the membrane were investigated. An asymmetric membrane with a dense top layer and a porous sublayer was obtained. The thickness of the dense top layer decreased with increasing amount of nonsolvent additive. Compared with pure PC membrane without additive(metal salt), the oxygen permeability and $O_2/N_2$ separation factor of the $PC/CuCl_2$ membrane are significantly improved. The oxygen permeability and $O_2/N_2$ separation factor is $5.25{\times}10^{-9}cm^3(STP){\cdot}cm/cm^2{\cdot}sec{\cdot}cmHg$ and 4.5, respectively. This improvement might be due to good interaction between metal salt and oxygen.

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노년기 교육프로그램 개발의 현황과 과제 (A Study on the Research Trends and Tasks in the Development of the Education Programs for the Elderly)

  • 송현애
    • 가정과삶의질연구
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    • 제29권5호
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    • pp.51-73
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    • 2011
  • Korean society with low fertility rate and high aging rate crisis has been tried very hard to find out alternatives to solve these social problems. These efforts resulted in increasing the development of education programs for the elderly. The education for the elderly have been development in various different academic fields. Therefore, this is the time to establish database for education programs which developed so far. The purpose of this study is to examine research trend in the field of education programs for the elderly in Korea. For this purpose, 62 education programs for the elderly which developed so far were analyzed. The results of this study were as followed. The topics of education programs for the elderly were divided into the following : a marriage enrichment programs for the elderly married couples, leisure programs, death education programs, health education programs, economic education programs, education programs for grandparents raising their grandchildren, etc. Based on the results of this analysis, the tasks of future research about education programs for the elderly were presented.

Analysis of gene expression during odontogenic differentiation of cultured human dental pulp cells

  • Seo, Min-Seock;Hwang, Kyung-Gyun;Kim, Hyong-Bum;Baek, Seung-Ho
    • Restorative Dentistry and Endodontics
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    • 제37권3호
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    • pp.142-148
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    • 2012
  • Objectives: We analyzed gene-expression profiles after 14 day odontogenic induction of human dental pulp cells (DPCs) using a DNA microarray and sought candidate genes possibly associated with mineralization. Materials and Methods: Induced human dental pulp cells were obtained by culturing DPCs in odontogenic induction medium (OM) for 14 day. Cells exposed to normal culture medium were used as controls. Total RNA was extracted from cells and analyzed by microarray analysis and the key results were confirmed selectively by reverse-transcriptase polymerase chain reaction (RT-PCR). We also performed a gene set enrichment analysis (GSEA) of the microarray data. Results: Six hundred and five genes among the 47,320 probes on the BeadChip differed by a factor of more than two-fold in the induced cells. Of these, 217 genes were upregulated, and 388 were down-regulated. GSEA revealed that in the induced cells, genes implicated in Apoptosis and Signaling by wingless MMTV integration (Wnt) were significantly upregulated. Conclusions: Genes implicated in Apoptosis and Signaling by Wnt are highly connected to the differentiation of dental pulp cells into odontoblast.