• Title/Summary/Keyword: IT Diffusion

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Oxygen Reduction of PAFC Gas Diffusion Electrode with Various Pt Impregnation Methods (인산형 연료전지용 기체확산전극의 백금촉매 담지방법에 따른 산소환원 특성)

  • Yoo, Duck-Young;Eun, Yeong-Chan;Shim, Joong-Pyo;Lee, Ju-Seong
    • Applied Chemistry for Engineering
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    • v.7 no.5
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    • pp.999-1005
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    • 1996
  • Pt catalyst on carbon black was prepared by colloidal method, ion exchanging method and methanol reducing method. The colloidal method has been used generally. At ion exchanging method, $H^+$ of functional group on carbon surface made by oxidation treatment was exchanged with Pt ion. At methanol reducing method, Pt was impregnated on carbon to reduce by methanol contained with surfactants. With TEM and XRD, Pt particle size impregnated on carbon by various methods was $30{\sim}50{\AA}$. Loading yield was about 100%, loading yield of ion exchanging method was 99.92% by DCP analysis and 99.87% by combustion method. Within 60 hour, current density of oxygen reduction was $460mA/cm^2$ at 0.7V(vs. RHE) at colloidal method. It was the better performance than catalyst prepared by ion exchanging, methanol reducing method. But, it was shown some decrease of performance for long operation time(after 100hour), catalyst prepared by methanol reducing method was shown stable performance.

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An Analysis on the R&D Productivity and Efficiency of Korea: Focused on Comparison with the OECD Countries (우리나라의 R&D 생산성 및 효율성 분석: OECD 국가와의 비교를 중심으로)

  • Kim, Young-H.;Kim, Sun-G.
    • Journal of Technology Innovation
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    • v.19 no.1
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    • pp.1-27
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    • 2011
  • This paper aims to measure and analyze R&D productivities and efficiencies of 17 major OECD countries including Korea over the 1984-2008 period by using the Malmquist Productivity Index and Data Envelopment Analysis, classifying R&D performance into an output and outcome aspects. It also searches the Korea's current status and characteristics in each R&D stage to enhance Total Factor Productivity (TFP) compared with other developed countries. Our major findings are the followings: (i) Korea's productivity index of R&D input vis-a-vis R&D output is very high (13.39% annual growth rate) compared with those of major advanced countries, whereas the annual average of efficiency index is very low (0.33), i.e. Korea's technical efficiency index has risen to 0.83 at the last time series started at 0.10 point and come up to the level of major advanced countries. (ii) the Korea's productivity index of R&D output vis-a-vis R&D outcome is very low (14.02% annual reduction rate) compared with those of major advanced countries, whereas the annual average of efficiency index is very high (0.22), i.e. Korea's integrated frontier technical efficiency index has dropped to 0.057 at the last time series started at 1.00 point and coming up to the level of major advanced countries. (iii) The productivity of R&D input vis-a-vis R&D outcome is positively correlated with that of R&D output vis-a-vis R&D outcome and the growth of R&D input factors. In a nutshell, it implicates that the effort to take advantage of R&D outputs, namely establishing the diffusion and commercialization system of technical knowledge to the level of developed countries, should be strengthened over that on the growth of R&D investment and output for enhancing R&D productivity and efficiency in Korea.

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Effects of 3rd Element Additions on the Oxidation Resistance of TiAi Intermetallics (합금원소 첨가가 TiAI계의 내산화성에 미치는 영향)

  • Kim, Bong-Gu;Hwang, Seong-Sik;Yang, Myeong-Seung;Kim, Gil-Mu;Kim, Jong-Jip
    • Korean Journal of Materials Research
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    • v.4 no.6
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    • pp.669-680
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    • 1994
  • Oxidation behaviour of TiAl intermetallic compounds with the addition of Cr, V, Si, Mo, or Nb was investigated at 900~$1100^{\circ}C$ under the atmospheric environment. The reaction products were examined by XRD, SEM equipped with WDX. The weight gain by continuous oxidation increased with the addition of Cr or V, but there was less weight gain when Mo, Si or Nb was added individually. he oxidation rate of Cr- or V-added TiAl was always larger than that of TiAI. However, oxidation rate of Si-, Mo- or Nb-added TiAl was almost same or smaller than that of TiAI. Thus, it is concluded that the addition of Cr or V did not improve the oxidation resistance, whereas the addition of Si, Mo or Nb improved the oxidation resistance. Oxides formed on TiAl with Mo, Si, and Nb were found to be more protective, resulting from the decrease in diffusion rate of the alloying elements and oxygen. Nb strengthened the tendency to form $AI_{2}O_{3}$ in the early stage of oxidation, due to the continuous $AI_{2}O_{3}$ layer formation and dense $Tio_{2}+AI_{2}O_{3}$ layer. According to the Pt-marker test of TiAI- 5wt%Nb, oxygen diffused mainly inward while oxides were formed on the substrate surface. Upon thermal cyclic oxidation at $900^{\circ}C$, it is shown that the addition of Cr or Nb improved the adherence of oxide scale to the substrate.

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Drying of Alaska Pollack in Controlled Conditions to Identify Major Factors for Textural Properties of Hwangtae (명태 건조과정에서 일어나는 수분과 수분활성도 변화가 명태건조품의 물성에 미치는 영향)

  • Ha, Ju-Yeoup;Lee, Sang-Hyun;Jung, Kyung-Jin;Jo, Young-Duk;Kim, Jae-Cherl
    • Journal of the Korean Society of Food Science and Nutrition
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    • v.39 no.12
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    • pp.1903-1907
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    • 2010
  • Drying curves for raw Alaska pollack seemed to follow typical food dehydration process with a very short initial settling down period. It was evident that there are some differences in drying rates between each part of fish body showing the highest drying rate for fish head followed by that for fish skin and that for flesh, presumably because of differences in water holding capacity of the components of each part. Specifically, the drying curve of fish flesh revealed that a boundary layer, thereby, a time period, existed which showed a big difference in moisture content and/or water activity as drying proceeds. The boundary layer in fish flesh with high moisture content between the layer contributes to reduce drying rate mainly as a consequence of protein aggregation resulting in hardening of fish flesh. The first boundary layer in this work appeared to show within several hours after initiation of drying. For Hwangtae, a naturally cyclic freeze-thaw dried and aged Alaska pollack which was popular in Korea, manufacturing process, it is clear that periodic moistening of boundary layer in fish flesh prohibits hardening fish flesh in boundary layer and enables steady moisture diffusion from inside of the fish flesh to surface of the fish body.

LOW PERMEABILITY THROUGH THE BLOOD-BRAIN BARRIER OF MORPHINE GLUCURONIDES.

  • Kang, Young-Sook;Ulrich Bickel;Oliver P. Schumacher;Karlheinz Voigt
    • Proceedings of the Korean Society of Applied Pharmacology
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    • 1996.04a
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    • pp.246-246
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    • 1996
  • The glucuronide conjugates of morphine have been claimed to exert significant neuropharmacological effects. Morphine-6-glucuronide (M6G) may be a potent opioid agonist in vivo, and morphine-3-glucuronide (M3G) may act as a weak opioid antagonist. The present study addressed the permeability of the blood-brain barrier (BBB) for these metabolites compared to morphine. Tracers were prepared by enzymatic glucuronidation of U-methyl-$^3$H]-morphine. Brain uptake in rats was measured by the internal carotid artery perfusion technique and after i.v. bolus injections. In the perfusion experiments morphine showed a permeability-surface area product (PS) of 3.52${\pm}$0.61 ${\mu}$L min$\^$-1/ g$\^$-1/ Uptake seems to be mediated by passive diffusion and was not saturable by 100 ${\mu}$M morphine in the perfusate. The BBB permeability of [$^3$H]-M3G and [$^3$H]-M6G was too low to be quantified after 5 min of perfusion. Brain uptake of [$^3$H]-M3G and [$^3$H]-M6G 60 min after i.v. bolus injection reached 0.0060${\pm}$0.0003 and 0.0030${\pm}$0.0005% injected dose per g, respectively. From these brain concentrations and from the corresponding plasma concentration - time curves, BBB PS values of 0.14${\pm}$ 0.02 ${\mu}$L min$\^$-1/g$\^$-1/ and 0.11 ${\pm}$ 0.01 ${\mu}$L min$\^$-1/g$\^$-1/, respectively, were calculated. The ratio of BBB PS values is complementary to the analgesic potencies of morphine and M6G after different routes of administration. The low PS of MSG explains, why it is approximate]y equipotent to morphine after systemic injection, although it is about 2 orders of magnitude more potent than morphine after administration directly into the central nervous system.

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Blood-neural Barrier: Intercellular Communication at Glio-Vascular Interface

  • Kim, Jeong-Hun;Kim, Jin-Hyoung;Park, Jeong-Ae;Lee, Sae-Won;Kim, Woo-Jean;Yu, Young-Suk;Kim, Kyu-Won
    • BMB Reports
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    • v.39 no.4
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    • pp.339-345
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    • 2006
  • The blood-neural barrier (BNB), including blood-brain barrier (BBB) and blood-retinal barrier (BRB), is an endothelial barrier constructed by an extensive network of endothelial cells, astrocytes and neurons to form functional 'neurovascular units', which has an important role in maintaining a precisely regulated microenvironment for reliable neuronal activity. Although failure of the BNB may be a precipitating event or a consequence, the breakdown of BNB is closely related with the development and progression of CNS diseases. Therefore, BNB is most essential in the regulation of microenvironment of the CNS. The BNB is a selective diffusion barrier characterized by tight junctions between endothelial cells, lack of fenestrations, and specific BNB transporters. The BNB have been shown to be astrocyte dependent, for it is formed by the CNS capillary endothelial cells, surrounded by astrocytic end-foot processes. Given the anatomical associations with endothelial cells, it could be supposed that astrocytes play a role in the development, maintenance, and breakdown of the BNB. Therefore, astrocytes-endothelial cells interaction influences the BNB in both physiological and pathological conditions. If we better understand mutual interactions between astrocytes and endothelial cells, in the near future, we could provide a critical solution to the BNB problems and create new opportunities for future success of treating CNS diseases. Here, we focused astrocyte-endothelial cell interaction in the formation and function of the BNB.

현대 서양복식에 나타난 이국취향 (Exoticism)에 관한 연구 -1980년대 중반~1991년의 서양복식을 중심으로- (The Study of Exoticism in Western Costume)

  • 송명진;양숙희
    • Journal of the Korean Society of Costume
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    • v.18
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    • pp.291-306
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    • 1992
  • From the mid-1980s '91s, remarkable Ethnicism and Primitivism in the Europe fashion trend could be represented as an exotic taste longing for secenery and emotion of non-europe area in the West. These phenomenon could be found out in connection with Acculturation, which means when two different cultures or more were contacted they were identified or merged in process of diffusion and change of them. This point of view was the culture anthropologic one that make a comparison and analysis of sameness and difference between cultures. The purpose of this study was to illuminate exotic taste represented in costume in the cluture-anthroplogic aspect, to compare with beauty of costume that each culture of costume and the meaning of the times due to those differences. an aspect of the exotic taste and character in the western costume that was inspected by dividing into 'Primitivism', 'Oriental element' and 'the element of a national costume in the East European bloc ' were as follows; First, Primitivism had something in common with what was pursued in the trend of Modern Art, through the late 19th century to the early 20th century. In fashion fettered by technique, the creation expressed in a free was and showed simple beauty of costume. At the same time, pure emotion expression, creative power and witty strong expression give the cognition of transcendency breaking the routine and the cognition of complexity of an included conception. Those are garments showing not only the primitive thought and mysticism but a fancy, an abstraction, and a life. Colors and accessaries which described nature and matched simple costume composition to the expression of various material or patterns transmitted the image of the primitive strongly. Second, "Drental element" which had an effect on western custome historically in a long time had outstanding luxurios adornmental beauty of custome. Extending from the Arab stated India, China, Korea, Japan, each national costume with a gay national culture became one of motif. Various ornamental factors expressed on Trapez Line, Sime Line and Drape, or Raied style, which did not restrict the body. Those were not only functional Easy Look, but were also satisfying human's ornamental desire. Third, national factors in the East European bloc are theme that begins to be embossed in the late 80's. In view of a political change and cultural situation with a double character of Europe and Orient, it was estimated that national factors have great importance in fashion. Item concerned with new concern appeared at Autumn & Winter collection. It shows elegant and graceful beauty of costume by adding a fur or jewel to simple form. These national factors in the East European bloc are simple form, but shows the difference in more cubic formation than form expressed in Primitivism or Oriental factors Exotic taste appeared form 80's to 91's, is thought to create an forgotten romantic emotion and traditional fashion

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A Study on the Establishment of Special Graduate Courses in Government Research Institutes (출연(연) 단설대학원 운영모델 연구)

  • 김갑수;김정흠;김전식;이규호;이병민;조봉제;현병환
    • Proceedings of the Korea Technology Innovation Society Conference
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    • 1998.05a
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    • pp.9-9
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    • 1998
  • 지난 수년동안 정부출연(연)의 연구개발활동의 효율화를 도모하기 위하여 정부와 과학기술계에서 논의되어 왔던 출연(연)의 석박사 교육과정 설립에 관하여 출연(연)관련자들의 의견을 모아 구체적인 설립모델을 제시하였다. 먼저 정부출연(연)에 석박사 교육과정 설치가 필요한 이유와 기대효과를 제시하고, 다음으로 단설대학원의 설립모델로는 크게 3가지 유형이 고려되었다. 가장 중요한 설립목적 및 기대효과로는 출연(연)의 목표지향적(mission-oriented) 연구에 파급지향적(diffusion-oriented) 메카니즘을 도입함으로써 출연(연)의 연구성과가 경제사회로 효과적으로 이전될 수 있도록 하기 위함이다. 단설대학원의 설립모델로서 첫째 유형은 각 출연(연)이 교육과정을 운영하는 개별대학원 모델이다. 이는 출연(연)의 연구기능과 교육기능을 현장에서 융합시켜 운영하는 것으로 설립이 비교적 용이하며 개별 출연(연)의 특수성을 살릴 수 있다. 출자형식으로 별도의 학교법인을 설립하는 방식과 내부규정으로 부설대학원을 설치운영하는 두 가지 방식 있을 수 있다. 둘째 유형은 출연(연) 연합대학원 모델이다. 출연(연)들이 연합으로 하나의 학교 법인을 설립하고 여기에 각 출연(연)들이 공동운영자로서 참여하는 방식이다 이때 연합대학원은 일종의 Virtual University 형태를 취하며 모든 교육은 참여 출연(연)에서 이루어지는 형태이다. 세 번째는 대학과 출연(연)이 연계대학원을 운영하는 모델이다. 대학의 대학원을 개방하여 출연(연) 측과 공동으로 운영하는 것으로 이는 별도의 학교법인 설립이 필요없다. 본 연구에서는 KAIST와의 연계대학원을 고찰하였다. 본 연구에서는 이들 각각의 모델에 대한 의미와 장점, 단점을 비교분석하고, 각 모델로 설립시의 법적 고려사항, 그리고 학사운영체제 등에 관해 구체적으로 고려하였다. 추가적으로 단설대학원의 설립에 관한 그간의 반대 및 우려사항에 대한 검토도 첨부하였다.한다. 선진국의 경우에도 우선 지원분야에 대한 연구비 배분은 5-10%사이이다. (ⅴ) 성과관리를 통한 지원효과의 극대화 : 기초과학의 지원에 있어서 그 성과를 특정한다는 것은 쉬운 일이 아니지만 연구비 지원효과를 극대화하기 위해서는 프로그램 평가를 통해 성과관리를 하여야 한다. (ⅵ) 효율적인 혁신시스템의 구축 : 혁신시스템의 효율적인 운영이 매우 중요하다. 이를 위해서는 첫째, 연구부문과 산업부문을 연결시킬 수 있고, 새로운 분야를 담아낼 수 있는 유연한 분야분류체계를 정립하여야 하고, 둘째 연구결과의 효율적인 활용이 이루어져야 하며, 셋째 연구지원기관간 연계시스템의 구축을 구축하여야 한다.s of rats with alveolar organism. (omitted)없었다 (P>0.05). 6. 분만 2 개월 전에 Se과 Vit. E를 투여한 한우 종빈우로부터 태어난 송아지의 혈중 Vit. E 농도에 미치는 효과를 검토한 결과, 투여구가 대조구보다 다소 높은 농도를 나타냈으나 처리구간 커다란 차이는 없었다 (P>0.05).ine oil, Phenthoate EC 및 Trichlorfon WP는 비교적 약효가 낮았다.>$^{\circ}$E/$\leq$30$^{\circ}$NW 단열군이 연구지역 내에서 지하수 유동성이 가장 높은 단열군으로 추정된다. 이러한 사실은 3개 시추공을 대상으로 실시한 시추공 내 물리검층과 정압주입시험에서도 확인된다.. It was resulted from increase of weight of single cocoon. "Manta"2.5ppm produced 22.2kg of cocoon. It is equal to 9% increase in index, as compared to that of control. In case of R-20458, the increasing rates were varied at the

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Purification of the Yolk Protein, and Identification of the Synthetic Site of Its Precursor in Eriocheir japonicus (Decapoda, Brachiura) (동남참게(Eriocheir japonicus)의 난황단백질 정제와 그 전구체의 합성부위 구명)

  • HAN Chang-Hee;BAE Hyun-Hwan
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.25 no.5
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    • pp.432-442
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    • 1992
  • To identify the histological site of synthesis of yolk protein precursor, vitellogenin, by immunocytochemical method in the freshwater crab Eriocheir japonicus, we purified the yolk protein, vitellin, from crude egg extracts, and prepared the anti-rabbit serum against vitellin. Then, the site of vitellogenin synthesis was demonstrated by immunotytochemical method with PAP(peroxidase-antiperoxidase) reaction using the rabbit antiserum aganist vitellin. Female specific serum protein was identified in female serum by immunoelectrophoresis and Ouchterlony's immunodiffusion test for mature male and female sera. Based on the immunoelectrophoresis and Ouchterlony's diffusion test for mature male and female sera and crude egg extracts using antiserum against vitellogenic female serum absorbed with male serum, the female specific serum protein was identified as vitellogenin, detected in female serum only. The major yolk protein, vitellin, was purified from the crude egg extracts by DEAE-cellulose ion exchange chromatography, followed by sepharose CL-4B gel filteration chromatography. The molecular weight of vitellin was estimated to be about 245,000 dalton by sepharose CL-4B gel filteration chromatography. from the results of immunological analysis for vitellin, it was found that the vitellin antiserum contained the antibody against vitellogenin. In the results of immunocytochemical reaction by PAP method with the rabbit antiserum against vitellin, the vitellogenic oocytes and the hepatopancreas of mature female showed positive PAP reaction, but not in follicle cells and previtellogenic oocytes nf ovary, muscle of female and mature male hepatopancreas. Therefore, it showed that the hepatopancreas of mature female is the site of vitellogenic synthesis.

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Analysis and Quantification of Seawater Infiltration by Wave Action in Coastal Zone (연안해역에서 파도에 의한 해수 침투이론의 비교와 정량화)

  • Cheong Cheong-jo;Choi Doo-hyoung;Kim Tae-keun;Okada Mitsumasa
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.4 no.4
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    • pp.3-11
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    • 2001
  • To know the seawater infiltration into tidal flat sediment in coastal area is very important, because it is significantly correlated with the infiltration and transportation of pollutants in soil, the supply of dissolved oxygen, nutrients and organic matter to benthic organisms for survival of benthic organisms and the seawater purification. So, we set up purpose to clarify the infiltration behavior of seawater by wave action in tidal flat, to clear the effects of slope of tidal flat and breaking wave height on seawater infiltration and to quantify the infiltration volume of seawater. For purpose, the seawater infiltration was studied with visualization method by using coloring tracer and transparent glass beads replaced as natural sediment in model tidal flat. Specific conclusions derived from this study are as follows. The semi-circular type infiltration of seawater by wave action into saturated sediment was a new infiltration behavior that was not considered in previous studies. The infiltration rate of seawater was increased with increasing of breaking wave height and slope of tidal flat. However, the effects of the slope was bigger than that of breaking wave height on seawater infiltration into tidal flat sediments. It was possible to calculate the infiltration volume of seawater by wave action in natural tidal flat sediment and in fields. Therefore, we can point out that wave action play an important role in the supply of dissolved oxygen, nutrients and organic matter to benthic organisms, transportation or diffusion of pollutants and seawater purification. So, we hope to be studied the supply of food to benthic organism, pollutant transport and seawater purification on the base of these results.

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