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Single crystal growth of ZnWO4 by the Czochralski method and characterization (Czochralski법에 의한 ZnWO4 단결정 성장 및 특성분석)

  • Lim, Chang-Sung
    • Analytical Science and Technology
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    • v.23 no.2
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    • pp.103-108
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    • 2010
  • Single crystals of $ZnWO_4$ with [100], [010] and [001] directions were successfully grown by the Czochralski method. The seed crystals for the single crystal growth of $ZnWO_4$ could be induced by the crystal growth using platinum wires applied by the capillary action from the melt. The growth conditions in each direction were investigated in terms of the variations of rotation speed, pulling rate and diameter of the grown crystals. The formation of cracking in the grown crystals during the cooling process could be prevented by annealing effect. The growth directions of the grown crystals were determined using Laue back reflection. The microscopic characteristics of the grown crystals in each direction were discussed, and their physical properties were evaluated for hardness, thermal expansion coefficients and dielectric constants.

Effects of Starch Concentrations and Soaking Periods of Acorn on Sensory Characteristics of Acorn Mooks(Starch Gels) (조전분 농도 및 침지 시일이 도토리묵의 관능적 특성에 미치는 영향)

  • Park, Sank-Ok;Kim, Kwang-Ok
    • Korean Journal of Food Science and Technology
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    • v.21 no.1
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    • pp.9-12
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    • 1989
  • Sensory characteristics of acorn gels were evaluated as affected by acorn starch concentrations(7, 8, 9, 10 and 11%) and by soaking periods(4, 8 and 16 days) of acorn and acorn flour. The characteristics evaluated were color, clarity, firmness, cohesiveness, flavor and astringency. Panelists indicated in the scoring test that all the characteristics were pronounced as the starch concentration increased, except clarity, The result of ranking test on gels made with acorn starch soaked for 4, 8 or 16 days indicated that color, firmness, cohesiveness, flavor and astringency decreased, as soaking period increased. However, the soaking periods did not affect clarity of acorn gels.

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A Study on Analysis and Assessment of the LCCO2 Emissions for Building Construction by Using the Life Cycle Assessment Methodology (전과정평가 방법론을 이용한 건물의 전과정 탄소 배출량 평가 및 분석에 관한 연구)

  • Cho, Su-Hyun
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2016.05a
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    • pp.259-260
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    • 2016
  • Recently, world-wide focusing on the interest for the reduction of greenhouse gas emissions associated with climate change and global warming, South Korea also has set up a national greenhouse gas reduction target and action plans seeking to achieve them. In particular, in the construction area, to encourage green building certification of the building and carbon labeling acquisition of building products, in order to reduce the environmental impact caused by the industrial activities have been in steady efforts. Therefore, this study estimates the life cycle carbon footprint of building construction materials applied to carbon emissions reduction technology and analyzes the results. Through the CO2 emissions analysis in construction phase and maintenance phase of the building, it provides basic resource for future research expansion and establishes a step-by-step whole life cycle carbon emissions reduction plan in new construction and existing buildings.

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A Case Study on Application of Dewatering Method for Slope Stability (사면안정성 확보를 위한 지하수위 저하공법 적용사례 연구)

  • Han, Jung-Geun;Shin, Ju-Oek;Hong, Ki-Kwon;Jung, Sun-Kuk;Lee, Yang-Kyu;Kim, Byung-Soo
    • Journal of the Korean Geosynthetics Society
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    • v.8 no.1
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    • pp.61-66
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    • 2009
  • This paper presented that the causes on failure of reinforced slope are analyzed which based on the analyzed result. It had been applied that a method of lowering the groundwater using deepwell for sump. For the stability analysis on applied method, a series of numerical analysis were carried out. Therefore, it could be confirmed that slope stability was affected the dewatering ability of groundwater by the rainfall and this method which was confirmed very reasonable and suitable methods for slope stability, during heavy rainfall, in field.

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Microstructure of $SrBi_2(Ta,Nb)_2O_9$ Thin Films on $SrTiO_3$(001) Single Crystal ($SrTiO_3$(001) 단결정 위에 제조된 $SrBi_2(Ta,Nb)_2O_9$ 박막의 미세구조)

  • 이지현
    • Journal of the Korean Ceramic Society
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    • v.37 no.10
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    • pp.1008-1013
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    • 2000
  • SrTi $O_3$(001) 단결정 기판 위에 졸-겔 스핀코팅으로 $SrBi_2(Ta,Nb)_2O_9$ 박막을 도포하고 그 결정화 과정을 고온 X-선 회절분석 (HTXRD)으로 추적하면서 Pt(111)/Ti/ $SiO_2$/Si 위에 성장한 박막과 비교하였다. SrTi $O_3$(001) 단결정 기판 위에 도포된 $SrBi_2Nb_2O_{9}$ 박막은 fluorite-like phase와 같은 transient phase를 거치지 않고 곧바로 순수한 $SrBi_2Nb_2O_9$ 상으로 결정화가 시작되었으며 결정화가 시작되는 온도인 ${\sim}540^{\circ}C$부터 c축 배향성장하였다. 또한 $SrB i_2(Ta,Nb)_2O_9$ 박막은 Ta/Nb 비에 관계없이 $SrTiO_3$(001) 위에서 모두 $(00{\ell})$로 배향되었으며, 코팅 횟수가 늘어나 필름의 두께가 증가함에 따라 c축 배향성은 미세한 감소를 보였다. $SrBi_2Nb_2O_9/SrTiO_3$단면을 TEM으로 관찰한 결과 $SrBi_2Nb_2O_9$은 대체로 불규칙한 크기의 다결정체로 되어 있었으나 계면 부근에서는 [001]$_{SBN}$//[001]$_{SrTi}$ $O_3$/, [100]$_{SBN}$//[100]$_{SrTi}$ $O_3$/라는 결정학적 관계를 가지며 에피탁샬 성장했음을 알 수 있었다.있었다.

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$n.cuInSe_2$-Polysulfide Solar Cells ($n.cuInSe_2$-Polysulfide Junction의 태양전지에 관한 연구)

  • Kim, Chang-Dae;Jeong, Hae-Mun;Jo, Dong-San
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.22 no.3
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    • pp.1-5
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    • 1985
  • CulnSe2 single crystals were grown by the Bridgman method. The n.CulnSe2 single cry seals with a carrier concentration of 2.6$\times$1016/㎤ were obtained by a thermal treatment of the grown CulnSe2 single crystals in selenium atmosphere. The solar cell of n.CulnSe2-3M KOH+3M Na2 S+4M S junction was prepared by using n.Culnsel single crystal as a photoanode, 3M KOH+SM Nat S+4M S as Polysulfide solutions. The FF of the solar cell was 0.44 under 100 mW/cml illumination condition, and the conversion efficiency was 5.67%.

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The Relationship Between Shooting Athletes' Achievement Goal Orientation, Self-management and Exercise Performance (사격선수의 성취목표성향과 자기관리 및 운동수행의 관계)

  • Ryu, Won-Yong
    • Journal of Digital Convergence
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    • v.13 no.2
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    • pp.361-369
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    • 2015
  • For the research object of this study 112 university shooting athletes, registered with Korea Shooting Federation in 2014, have been selected. Statistics processing was carried out through SPSS 16.0 and AMOS 7.0. The following results were obtained by analysis of frequency, exploratory factor analysis, confirmatory factor analysis, correlation analysis and structural equation model analysis to serve it's purpose. First, task orientation had passive influence on self-management. Second, task orientation and ego-orientation had passive influence on perceived exercise performance. Third, self-management had passive influence on perceived exercise performance.

A Study on Growth of Amethyst (자수정 육성에 관한 연구)

  • 박로학;유영문
    • Korean Journal of Crystallography
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    • v.2 no.1
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    • pp.23-26
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    • 1991
  • Amethysts were grown hydrothemally. The origin of amethyst color is iron center, which is developed by correlation between Fe3+(substitutional) and Fe3+ (interstitial)1). Crackless amethysts without smoky centers were grown only from major (1011) and minor (1101) seeds on K2c03 solutions. The violet color of amethyst depended on both iron concentration and amount of irradiation of r-ray. Increasing the iron concentration resulted in the deep violet color. Also amethysts color were changed to dark proportional to amount of irradiation. From visible spectra it was found that increasing the amount of irradiation affected not the character of individual iron center but the total number of iron centers.

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A Survey Research on Students's Understanding of Definition, Formula, and Theorem at College Mathematics Classes (대학수학에서 정의, 공식, 정리의 이해도 검사)

  • Kim, Byung-Moo
    • Communications of Mathematical Education
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    • v.22 no.3
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    • pp.311-335
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    • 2008
  • The importance of students' precise understanding of mathematical definitions, formulas, and theorems can not be underestimated. In this survey research, we attempted to evaluate students' understanding of the concepts of five topics -limit, continuity and intermediate theorem, derivative, application of derivative and integral. On the basis of the research result, this paper suggests that we need to 1) be more inventive and speculative in making test problems, 2) explain the examples and counter-examples more concretely, 3) stress and repeat the basic concepts on the stage of introducing new concepts, 4) develop more effective problems for the measure of students' understanding of mathematical concepts, 5) use developed problems in actual teaching.

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The Relationship among Influencer Interpersonal Trust, Brand Image and Purchase Intention for SNS(Social Network Service) Users (SNS 이용자들의 인플루언서 대인신뢰, 브랜드이미지 및 구매의도와의 관계)

  • Han, Jee Hoon
    • The Journal of the Korea Contents Association
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    • v.20 no.1
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    • pp.31-44
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    • 2020
  • The purpose of this study is to investigate the relationship among SNS users' interpersonal trust, brand image and purchase intention. A total of 335 questionnaires were collected during 6 days by Embrain online research company. Collected data were analyzed by SPSSWIN and AMOS program and frequency analysis, confirmatory factor analysis, validity test, correlation analysis and structural equation model analysis were performed. The results of verifying the relationship among variables are as follows. First, SNS users' interpersonal trust in influencers had positively influenced by brand image. Second, brand image sold by influencers had positively influenced by purchase intention. Third, SNS users' interpersonal trust in influencers had a significant effect on purchase intention.