• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 1996년도 봄 학술발표회 논문집
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• pp.165-172
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• 1996

Recently, the response of a high-rise building to external dynamic force created by wind and earthquake has received much attention. This response is dependent on wind intensity, surrounding environment, building size, shape, mass, stiffness and amount of energy dissipation available in the system. The study has been done on these parameters. Attempts have been made to increase the damping in building system and thereby reduce structural response. These attempts have centered on adding an energy-dissipative system(passive tuned mass damper; passive TMD) to the building system and increasing the overall effective damping. In this paper the optimum condition of passive TMD will be derived with respect to random excitation and the properties of the optimum condition will have been studied.

• 한국세라믹학회지
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• 제31권4호
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• pp.436-447
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• 1994

ZnO transparent conducting thin film, which is a strong candidate for a transparent electrical contact in optoelectronic devices, was prepared by the vapour spraying method on the slide glass in nitrogen ambient at the atmospheric pressure. The structural, optical and electrical properties of films show a strong dependence on substrate temperature, and the optimum range of deposition temperature existed to obtain TCO(Transparent Conducting Oxide) films. At the higher temperatures, milky films were obtained. In such optimum range, the bandgap in ZnO films was determined from the spectral dependence of absorption coefficient and electrical characteristics were characterized with by the Hall mobility and carrier concentration.

• 한국기계연구소 소보
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• 통권20호
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• pp.71-78
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• 1990

This investigation was undertaken to establish the technologies of grain refinement and modification, and to characterize material properties, essential for high quality aluminum alloy castings. Grain refinement seldom changed DAS and eutectic Si size, but largely decrease grain size. The variations of grain size induced by grain refinement had a great influence on the elongation without changes in the tensile strength or yield strength. The optimum Ti level lies between 0.1% and 0.16% to achieve the best possible mechanical properties. DAS and grain size were little affected, but eutectic Si size was greatly refined by modification. The variation of eutectic Si size had a great effect on the elongation, impact value, fracture toughness and fatigue crack propagation rate without changes in the tensile strength or yield strength. The Sr content of 0.015% is optimum to modification.

• 대한전자공학회논문지
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• 제23권4호
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• pp.498-505
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• 1986

In2O3: Sn(ITO) transparent conducting films were fabricated by the electron beam evaporation method. The dependence of their electrical and optical properties on deposition conditions were examined. The optimum evaporation conditions were such that the deposition rate was 5-10\ulcornersec, oxygen partial pressure was 4x10**_4 torr, substate temperatudre was above 300\ulcorner, and SnO2 doping rate was 10 mol%. The values of sheet resistance and transmittance of the films in visible region fabricated under these optimum conditins were 12\ulcorner/ and 87-99%, respecively. And the energy conversion efficiency of the SIS solar cell fabricated using ITO was 9.16%. It is shown that the transparent conducting films can be applied to the TV camear pick-up tube and solar cell.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2013년도 추계 학술논문 발표대회
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• pp.21-22
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• 2013

Nowadays, the fiber which mixed with concrete matrix always has low adhesion with cement paste. It's difficult to use fiber to reinforce the structure. For more adding fiber in concrete would cause some problems as the low flowability and surface polishing. Further study is needed in fiber using. In this research, further study in fiber reinforced concrete has been invested. Various fibers with different properties have been used to prevent cracking. Fiber reinforced concrete's fundamental properties as slump, air content, compressive strength and tensile strength have been tested. Optimum type of the fiber and optimum addition ratio of fiber has been invested to increase the utility of the fiber which used in concrete.

• 한국통신학회논문지
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• 제40권12호
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• pp.2324-2330
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• 2015

충격성 잡음하의 블라인드 신호처리 분야에서 최대 상호 코렌트로피 알고리듬 (MCC)이 MSE 기반의 알고리듬에 비해 우수한 성능을 보인다. 그러나 MCC 알고리듬에 대한 최적 가중치 조건들이나 충격성 잡음에 대한 내성과 관련된 특성들은 아직 충분히 연구되지 못한 상태이다. 이 논문에서는 MSE기반의 LMS 알고리듬과 비교를 통해 MCC의 최적 가중치의 성질을 분석하여 MCC 알고리듬의 최적 가중치가 MSE기반의 LMS 알고리듬과 같다는 보인다. 또한 MCC의 최적 가중치가 충격성 잡음 하에서도 동요 없이 안정을 유지하는 요인이 입력 크기 조정에 있다는 것을 시뮬레이션을 통해 입증하였다.

• Mass Spectrometry Letters
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• 제6권3호
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• pp.59-64
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• 2015

Quadrupole ion trap mass analyzer with a simplified geometry, namely, the cylindrical ion trap (CIT), has been shown to be well-suited using in miniature mass spectrometry and even in mass spectrometer arrays. Computation of stability regions is of particular importance in designing and assembling an ion trap. However, solving CIT equations are rather more difficult and complex than QIT equations, so, analytical and matrix methods have been widely used to calculate the stability regions. In this article we present the results of numerical simulations of the physical properties and the fractional mass resolutions m/Δm of the confined ions in the first stability region was analyzed by the fifth order Runge-Kutta method (RKM5) at the optimum radius size for both ion traps. Because of similarity the both results, having determining the optimum radius, we can make much easier to design CIT. Also, the simulated results has been performed a high precision in the resolution of trapped ions at the optimum radius size.

• 대한기계학회논문집B
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• 제20권6호
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• pp.1921-1930
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• 1996

To design an optimum engine intake system, a flow model for the intake manifold was developed by the finite difference method. The flow in the intake manifold was one-dimensional, and the finite difference equations were derived from governing equations of flow, continuity, momentum and energy. The thermodynamic properties of the cylinder were found by the first law of thermodynamics, and the boundary conditions were formulated using steady flow model. By comparing the calculated results with experimental data, the appropriate boundary conditions and convergence limits for the flow model were established. From this model, the optimum manifold lengths at different engine operating conditions were investigated. The optimum manifold length became shorter when the engine speeds were increased. The effect of intake valve timings on inlet air mass was also studied by this model. Advancing intake valve opening decreased inlet air mass slightly, and the optimum intake valve closing was found. The difference in inlet air mass between cylinders was very small in this engine.

• 공업화학
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• 제7권3호
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• pp.565-572
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• 1996

천연고무(NR), 부타디엔 고무(BR), 오일 투입량을 변량한 스티렌-부타디엔 고무(SBR)를 기본으로 하는 고무배합을 통하여 카본블랙의 최적 투입량에 대하여 연구하였다. 카본블랙의 최적 투입량은 Lee 이론을 기초하여 L 인자 값과 카본블랙의 부피비와의 상관 관계를 통하여 결정하였다. 그리고 얻어진 최적 투입량 값을 고무 물성 시험 결과를 통하여 재검증 하였다. 고무 종류별 카본블랙의 최적 투입량값은 각각 NR 60 phr, BR 57 phr, SBR-A 65 phr, SBR-B 70 phr, SBR-C 76 phr로 얻어졌다. 또한 오일의 함량을 20 phr씩 증가시킬때 마다 약 5phr 정도의 최적 투입량이 증가함을 관찰할 수 있었다. L 인자값을 통하여 얻어진 카본블랙의 최적 투입량은 인장강도와 가장 밀접한 관계가 있었으며 최대 인장강도 값을 갖는 카본블랙의 투입량 근처에서 형성되었다.

• International Journal of Industrial Entomology and Biomaterials
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• 제13권1호
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• pp.45-50
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• 2006

Papers were prepared from cut cocoons and mulberry branches, which are byproducts from sericulture industry. The long filament of silk should be cut into appropriate length in order to prepare paper and this was achieved by chemical method. By a mixture of sodium hydroxide and sodium carbonate solution, the silk filaments were cut into short fibers (less than 1 mm in length). Since the short silk fibers (sSf) could not bind each other by itself, starch and poly(ethylene oxide)(PEO) were added as a bonding agent. When starch and PEO were used in a ratio of 3:7, the silk papers had optimum mechanical properties for paper. Fibers from the skin of mulberry branches (MBF) were added to sSf to enhance the mechanical properties of pure silk paper. Bleaching of MBF was performed with a mixture of hydrogen peroxide and sodium silicate. The mechanical properties were greatly enhanced and the optimum blend ratio of MBF and sSf were 7:3. The mulberry/silk paper has good absorption property against formaldehyde, and therefore, the paper could be applied as a wall paper for preventing the sick house syndrome.