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Synthesis of potassium titanate by wet process (습식법에 의한 티탄산칼륨 섬유의 합성)

  • 강대갑;송종택
    • Journal of the Korean Crystal Growth and Crystal Technology
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    • v.5 no.3
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    • pp.278-283
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    • 1995
  • The potassium titanate fibres were synthesized with wet process by the addition of KOH solution to the TiOz gel produced by the reaction between element titanium particles and $H_2O_2$ solution at $50^{\circ}C$. And then they were characterized by XRD, SEM and FT - IR. It was found that potassium titanate fibres were mainly affected by KOH/TiOz mole ratio, synthesis time and aging time in this wet process employed. For $KOH/TiO_2 = 1/1$, synthesizing time 24 hrs, aging time 24 hrs and calcination temperature of TEX>$900^{\circ}C$ for 1 hr, their products were mainly found to be potassium tetratitanate which had thin and long fibres in the range of 10 ~ 20 mm. As the synthesizing time increased and the amount of KOH decreased, potassium tetratitanate was converted into potassium hexatitanate. Also, the length of their fibres became short.

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Studies on the Nutritive Value of Korean Foods (Report 5) (한국(韓國) 상용식품(常用食品) 영양가(營養價) 조사보고(調査報告) (제 5 보)(第 5 報))

  • Yu, J.Y.;Yun, S.R.;Kim, K.K.;Kwon, H.H.;Kim, I.P.;Ahn, K.O.
    • Journal of Nutrition and Health
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    • v.6 no.1
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    • pp.11-13
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    • 1973
  • The nutritive value of foods is the most essential and fundamental data in food administration, nutrition surveys, dietary clinic, and in the conduct of nutritional education. The nutritive values of 283 different kinds of selected Korean foods were investigated and reported in our previous reports already. In this report, another 21 kinds of Korean foods are studied for their proximate components, minerals and vitamins. The foods were sampled at random from the markets or from cultivating fields. The methods of sampling and of chemical analysis were same as employed in the previous reports. The results are shown in the table. The nutritive value of the rest of Korean foods will be studied continuously.

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Implementation of Rank/Select Data Structure using Alphabet Frequency (문자의 빈도수를 고려한 Rank/Select 자료구조 구현)

  • Kwon, Yoo-Jin;Lee, Sun-Ho;Park, Kun-Soo
    • Journal of KIISE:Computer Systems and Theory
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    • v.36 no.4
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    • pp.283-290
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    • 2009
  • The rank/select data structure is a basic tool of succinct representations for several data structures such as trees, graphs and text indexes. For a given string sequence, it is used to answer the occurrence of characters up to a certain position. In previous studies, theoretical rank/select data structures were proposed, but they didn't support practical operational time and space. In this paper, we propose a simple solution for implementing rank/select data structures efficiently. According to experiments, our methods without complex encodings achieve nH$_0$ + O(n) bits of theoretical size and perform rank/select operations faster than the original HSS data structure.

Performance Evaluations of Mock-up Tests for ALC Panel Curtain Wall in Building Exterior (ALC 패널을 활용한 건축물 외장 커튼월에 대한 Mock-up Test 성능 평가 연구)

  • Kim, Young-Ho;Lee, Yong-Soo
    • Journal of The Korean Digital Architecture Interior Association
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    • v.13 no.4
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    • pp.25-32
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    • 2013
  • The green building is one of biggest factors to go the goal of energy saving and environmental conservation, reduction of energy consumption, friendly energy technology, recycling of resource, and environmental pollution reduction technology. The purpose of these green buildings realized by the energy-saving technology such as the exterior materials or curtain wall system. The curtain wall system is a element that come to insulated portions of building envelope that results in heat loss. The purpose of this paper is to carried out mock-up tests for exterior wall used in autoclaved lightweight concrete panels in green building practices. Mock-up test execute a mixed process between standard test procedure and complex test procedure based on AAMA 501(American Society for Testing and Materials) and ASTM 283, ASTM 330(American Society for Testing and Materials). In results, tests meet the requirements that grant values in steps of procedures provided on ASTM and AAMA. ALC panel is suitable for a exterior wall product to be gratified thermal cycling performance and structural capacity, deflection(H/200) and lateral displacement(H/50), for curtain walls.

An experimental study on nucleate boiling of ternary refrigerant R407C (삼중 혼합 냉매 R407C의 핵비등 열전달 특성에 관한 실험적 연구)

  • Kim, S.H.;Kwak, K.M.;Bai, C.H.;Chung, M.
    • Korean Journal of Air-Conditioning and Refrigeration Engineering
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    • v.9 no.3
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    • pp.276-283
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    • 1997
  • The nucleate boiling heat transfer experiments are performed using a ternary refrigerant R407C which is a candidate of alternatives of HCFC 22. The boiling phenomena for R-32, R-125, and R-134a which are the constituent refrigerants of R407C are also investigated to give the foundation of theoretical research for the mixture component boiling. The nucleate boiling heat transfer coefficients of R407C is less than those of HCFC 22 which has the similar physical and transport properties. Since the experimental results show the deterioration of boiling heat transfer coefficients of ternary mixture refrigerants R407C, the boiling heat transfer coefficients of R407C cannot be obtained by the linear combination of boiling heat transfer coefficients from its constituent components R-32, R125, and R134a.

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Characterization of the Thermophilic Bacterium Geobacillus sp. Strain GWE1 Isolated from a Sterilization Oven

  • Correa-Llanten, Daniela;Larrain-Linton, Juanita;Munoz, Patricio A.;Castro, Miguel;Boehmwald, Freddy;Blamey, Jenny M.
    • Microbiology and Biotechnology Letters
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    • v.41 no.3
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    • pp.278-283
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    • 2013
  • A gram-positive, rod-shaped, spore-forming, motile thermophilic bacterium was isolated from a sterilization oven. The microorganism GWE1, formally named Geobacillus wiegelii identified as a member of the genus Geobacillus. GWE1 grew under aerobic conditions of between $60-80^{\circ}C$ (optimum $670^{\circ}C$), in a pH range of 3.0-8.0 (optimum $pH^{70^{\circ}C}$ 5.8), and between 0 and 2 M NaCl (optimum 0.3 M). The membrane polar lipids were dominated by branched saturated fatty acids, which included as the major constituents; iso-15:0 (13.3%), 16:1(${\omega}7$) (12.8%), 16:0 (28.5%), iso-17:0 (13.5%) and anteiso-17:0 (12.3%). The DNA G+C content was 47.2 mol% (determined by HPLC). The 16S rRNA gene sequence of GWE1 showed a high similarity with Geobacillus caldoxylosilyticus (97%). However, the level of DNA-DNA relatedness was only 58%. These data suggest that GWE1 is probably a novel specie of the genus Geobacillus.

Vritual Hand Animation Using Virtual Glove and VRML (Virtual Glove와 VRML을 이용한 Virtual Hand 애니메이션)

  • Ahn, J.Y.;Kim, D.O.;Lee, D.H.;Kim, N.K.;Kim, J.H.;Min, B.G.
    • Proceedings of the KOSOMBE Conference
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    • v.1998 no.11
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    • pp.283-284
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    • 1998
  • The Virtual Reality Technology makes you feel like you are in the situation which has been made up by using the information inputted through the device which is connected with the body part. If the image which is taken from CT, MRI is reorganized in 3D, it can present the shape of the human organ more clearly. So It is more likely to be used in the operation which needs the diversified examination about mutual relation with each part in a place of 3D or confirmation of the planed information. We developed the Technology which can reorganize the image from the CT into the 3D data and represent the 3D movement of the finger according to the hand.

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Phospholipase $C{\gamma}1$ Inhibitory Principles from the Sarcotestas of Ginkgo biloba (2) (은행(銀杏) 종의(種衣)의 Phospholipase $C{\gamma}1$ 저해 활성 성분 (2))

  • Lee, Ji-Suk;Cho, You-Sun;Lee, Hyun-Sun;Ahn, Jong-Seog;Kim, Jin-Woong
    • Korean Journal of Pharmacognosy
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    • v.30 no.3
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    • pp.280-283
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    • 1999
  • Using the bioassay-guided fractionation and isolation technique, two $PLC{\gamma}1$ inhibitors were isolated from the sarcotestas of Ginkgo biloba (Ginkgoaceae). The structures of these compounds were identified as (3R)-(-)-8-hydroxy-3-(6'-pentadecenyl)3,4-dihydroisocoumarin (1) and 3-heptadecen-2-one (2) by UV, IR, MS, $^1H-NMR$, $^{13}C-NMR$ and $^1H-^{13}C\;COSY$. Isolate compounds 1 and 2 have not been reported previously from the sarcotestas of G. biloba and Ginkgoaceae, respectively. In addtion, these compounds showed significant $PLC{\gamma}1$ inhibitory effects with the $IC_{50}$ of the 9.7 (1) and $25.6\;{\mu}M\;(2)$.

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Comparison of the Antibacterial Activity of Domestic Cirsium japonicum Collected from Different Regions (지역별 국내 자생 엉겅퀴 추출물의 항균 활성)

  • Jang, Miran;Park, Hyejin;Hong, Eunyeong;Kim, Gun-Hee
    • Korean journal of food and cookery science
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    • v.30 no.3
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    • pp.278-283
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    • 2014
  • This study was investigated the antibacterial activities of Cirsium japonicum from extracts five regions(Chungnam, Gyeonggi, Gangwon, Jeju and Jeonnam) extract against six food-borne pathogenes(Bacillus cereus, Bacillus subtilis, Staphylococcus aureus, Listeria monocytogenes, Salmonella enterica and Vibrio vulnificus) using the broth dilution and agar diffusion method. At concentrations between 0 and $750{\mu}g/mL$ the extracts showed an antibacterial effect against all tested bacteria. The antibacterial activities of Cirsium japonicum from Jeju and Gangwon are stronger than others. The minimum inhibitory concentration(MIC) values against the six bacteria ranged from 93.75 to $750{\mu}g/mL$. In time killing assay(cell growth curves), the tested bacteria inactivated upon exposure to the extracts for 24h. At the 24h exposure to the extracts, all bacteria were inhibited to over 70% for growth. In particular, Bacillus subtilis, Salmonella enterica and Vibrio vulnificus conveyed an inhibition of growth to almost complete. It is anticipated that Cirsium japonicum extracts may have greater potential as natural food preservatives.

PMMA Synthesized Using an Atmospheric AC Plasma (대기압 AC 플라즈마를 이용한 PMMA 합성)

  • Yu, In-Geun;Eom, Sang-Heum;Yun, Seong-Yeong
    • Proceedings of the Korean Institute of Surface Engineering Conference
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    • 2016.11a
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    • pp.184-184
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    • 2016
  • 대기압 플라즈마를 이용한 폴리머 합성은 기존의 합성방법에 비해 간단하고 쉽게 폴리머를 합성할 수 있다는 장점이 있다. 대부분의 폴리머는 합성온도가 $150^{\circ}C$ 이하이기 때문에 각 폴리머에 적합한 온도를 제어하는 것이 핵심이라 할 수 있다. 본 연구에서는 폴리머 합성온도를 제어하기 위하여 플라즈마 방전전극에 모노머를 직접 주입하지 않고 간접적인 방법을 선택했다. 그리고 모노머는 액체 공급 장치를 이용해 플라즈마의 가스량과 파워를 제어하면서 폴리머를 합성의 조건을 찾았다. AC 플라즈마를 이용해 methyl methacrylate($C_5H_8O_2$) 모노머를 폴리머로 합성했으며, 그 결과는 FTIR, XRD 등으로 분석하고 특성을 평가했다. FTIR의 결과, C-O, C-H, C=O 등의 전형적인 poly methyl methacrylate(PMMA)의 피크를 확인할 수 있었다. 그리고 XRD의 관찰결과 C1s 및 O1s의 각 binding energy가 각각 283, 285, 288 eV 및 533 eV 주변에서 확인되었다. 그리고 합성시간에 따라 폴리머의 두께가 비례해서 증가하는 것을 관찰할 수 있었다. 실험결과, AC 플라즈마를 이용한 폴리머합성은 가능한 것으로 확인되었으며 소형화 및 휴대가 가능하기 때문에 식품, 바이오, 의약품, 의료용품 등의 현장포장 등 여러 가지 용도로 활용이 가능할 것으로 판단된다.

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