• Steel and Composite Structures
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• 제47권3호
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• pp.365-374
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• 2023

This paper presents a new scheme for constructing locking-free finite elements in thick and thin plates, called Discrete Shear Gap element (DSG), using multiphase material topology optimization for triangular elements of Reissner-Mindlin plates. Besides, common methods are also presented in this article, such as quadrilateral element (Q4) and reduced integration method. Moreover, when the plate gets too thin, the transverse shear-locking problem arises. To avoid that phenomenon, the stabilized discrete shear gap technique is utilized in the DSG3 system stiffness matrix formulation. The accuracy and efficiency of DSG are demonstrated by the numerical examples, and many superior properties are presented, such as being a strong competitor to the common kind of Q4 elements in the static topology optimization and its computed results are confirmed against those derived from the three-node triangular element, and other existing solutions.

• 대한전기학회논문지
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• 제35권11호
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• pp.479-486
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• 1986

It is necessary to consider a rotor movement in dynamic analysis on the flux distribution of electric machinery by FEM. Therefore, if air-gap domain was subdivided into triangular elements, computation results contain errors due to variation of element shape in air-gap because the nodal points corresponding to the rotor are displaced in analyzing domain for the time difference. In order to reduce this errors, the paper presents a application of a Macro Air-gap Element that interpolation function is obtained analytically and a means to join it with linear triangular elements in the rotating machine or in the linear machine. At the end of paper, setting up analytic domain model, it compares analytic solution with the computation results of Macro Air-gap Element appliction and that of linear triangular element subdivision only to each cases of nodal displacement. And it carries out that errors due to variation of element shape are reduced effectively by application of a Macro air-gap element.

• 한국건설관리학회논문집
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• 제13권5호
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• pp.125-134
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• 2012

건설산업에 있어서 녹색 또는 그린(Green)은 차세대 신 성장동력의 핵심적인 키워드로 부상하고 있다. 녹색건설 경쟁력을 갖추는 것은 건설기업의 생존과 발전을 위해 중요하며 이를 위해 녹색건설 경쟁력 요인에 대한 이해는 필수적이다. 본 연구의 목적은 건설기업이 녹색건설 경쟁력을 확보하기 위해 요구되는 경쟁력 요인을 발굴하고 Gap 분석 기법을 통해 경쟁력 요인의 중요도와 현 수준을 분석하여 주요 특징과 시사점을 도출하는데 있다. 녹색건설 경쟁력 요인에 대한 이해는 건설기업의 녹색건설 전략 수립을 위한 선행 작업이며 동시에 녹색건설 관련 정책 및 제도 수립에 있어 건설기업에게 어떤 동기부여를 해야 하는지를 이해하기 위해 필수적이다. 본 연구를 통해 나타난 주요 결과를 요약하면, 첫째, 녹색건설 경쟁력의 중요도와 현 수준을 분석한 결과 중요도와 비교하여 현 수준이 모두 낮은 것으로 나타났다. 둘째, 녹색건설 경쟁력의 중요도와 현 수준 관점에서 CEO 역량 부문은 큰 격차가 없는 것으로 나타났지만 기업 역량 부문에서는 큰 격차가 있는 것으로 나타났다. 셋째, 녹색건설의 R&D 전략과 녹색건설 협력업체의 보유 및 협업 역량이 중요도와 현 수준의 차이(Gap)가 가장 크게 나타났다.

• 대한수학회보
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• 제47권2호
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• pp.433-442
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• 2010

$\tilde{G}(P,\;Q)$, a new generalization of the set of gap numbers of a pair of points, was described in [1]. Here we study gap numbers of local subring $R\;=\;\cal{K}\;+\;C$ of algebraic function field over a finite field and we give a formula for the number of elements of $\tilde{G}(P,\;Q)$ depending on pure gaps and R.

• Carbon letters
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• 제9권2호
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• pp.131-136
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• 2008

In order to investigate the effect of doping C, N, B and F elements on $TiO_2$ for reducing the band gap, the heat treatment of $TiO_2$ was carried out with tetraethylammonium tetrafluoroborate. Through XRD and XPS analysis, the C, N, B and F doped anatase $TiO_2$ was confirmed. According to the increase of temperature during treatment, the particle size was increased due to aggregation of $TiO_2$ with elements (B, C, N and F). To investigate the capacity of photocatalyst for degradation of dye under solar light, the degradation of acridine orange and methylene blue was conducted. The degradation of dyes was carried out successfully under solar light indicating the effect of doping elements (B, C, N and F) on $TiO_2$ for reducing the band gap effectively.

• Carbon letters
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• 제10권2호
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• pp.123-130
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• 2009

Multi-elements doped $TiO_2$ was prepared as a new photocatalyst in order to decrease the band gap of $TiO_2$ by sol-gel process which can provide the large active sites of $TiO_2$. Multi-elements were doped by using a single precursor, tetraethylammonium tetrafluoroborate (TEATFB). By the benefit of large specific surface area of $TiO_2$ prepared by sol-gel process, catalysts showed initial fast removal of dye. The photoactivity showed that the doped catalysts significantly promote the light reactivity than undoped $TiO_2$. The commendable photoactivity of prepared catalysts is predominantly attributable to the doping of anions which may reduce the band gap.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 제39회 하계학술대회
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• pp.1545-1546
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• 2008

In this study, an image processing method with FRANSAC(Fuzzy RANSAC) is presented and discussed for the development of a microscopic gap measuring algorithm. Many problems in edge detection processing are mainly occurred by the illumination system. A serious problem is that the edge set of gap could include the error elements that have relatively larger error than normal. This problem leads to a incorrect measurement of gap. We present a gap measuring algorithm using FRANSAC[1] that is a representative robust estimation algorithm. FRANSAC is peformed by first categorizing all data into good sample set, bad sample set and vague sample set using a fuzzy classification and then sampling in only good sample set. Experimental results show that the presented gap measuring algorithm gives a higher accurate value of gap especially for the more noisy image data.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.953-956
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• 2008

Using the theoretical model of Auger electron emission, effects of MgO properties which include band gap energy, escape probability, gas ion, and doping elements on the yield of secondary electron emission were examined. The results indicated that the band gap of MgO must be decreased and escape probability must be enhanced in order to increase the yield of secondary electrons from Xe ions and that may proved to be a critical for achieving high luminance efficacy in ac-PDPs.

• 농약과학회지
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• 제9권2호
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• pp.113-121
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• 2005

국가차원에서 식품안전 프로그램은 소비자보호와 식인성질환의 예방을 기본요소로 하고 있으며 정부, 식품산업, 소비자가 책임질 일이다. 여기에서는 WHO에서 제안하고 있는 식품안전 프로그램의 원칙을 소개한 다음 식품생산에 사용되는 의도적 첨가물의 잔류기준 설정에서 GAP의 중요성, 국제기구와 국내에서 잔류농약의 기준설정에 활용되고 있는 절차와 차이점을 지적하였다. 결론적으로 잔류농약에 대한 국내기준을 Codex 기준과 조화시키는데 필요한 사항들을 건의하였다.

• 한국전기전자재료학회논문지
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• 제11권9호
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• pp.693-699
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• 1998

In this work $Cd_4GeS_6:Co^{2+}$(0.5mole%) single crystals were grown by the chemical transporting reactiov(CTR) method using high purity(6N) elements. The grown single crystals crystallized in a monoclinic structure(space group Cc). The direct optical energy gap of this single crystals was found to be 2.445eV at 300K and the temperature dependence of optical energy gap was fitted well to Varshni equation. But at temperatures lower than 70K an anomalous temperature dependence of the optical energy gap was obtained. This anomalous temperature dependence accored well with the anomalous temperature dependence of the unit cell volume. Also, the entropy, enthalpy and heat capacity were deduced from the temperature dependence of optical energy gaps.