• Composites Research
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• 제23권5호
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• pp.1-7
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• 2010

NBR과 강판의 접착특성을 향상시키기 위해 대기압 화염 플라즈마(APFP) 처리 장치가 사용되었다. 가장 우수한 접착특성을 나타내는 최적 조건을 찾기 위해 다양한 처리 조건(처리속도, 거리)에 따른 효과에 대한 실험적 연구를 하였다. 주어진 조건에서 버너 포트와 강판의 최적 거리는 40mm, 버너 포트의 최적 처리속도는 50m/min였다. APFP 처리 후 접착제를 두 번 도포한 강판의 접착강도는 접착제만 도포한 경우보다 20.5% 증가하였다. 본 연구를 통해서 대기압 화염 플라즈마 처리에 의한 강판의 표면개질이 고무와 강의 접착강도를 증가시키는 적절하면서도 응용이 가능한 방법임을 확인하였다.

• 복합신소재구조학회 논문집
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• 제2권3호
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• pp.30-35
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• 2011

본 연구에서는 신형상 층고절감형 합성보에 대한 최적단면을 도출하기 위해 단면성능 계산 프로그램을 개발하여 단면성능에 대해 비교 분석을 하였다. 신형상 합성보는 상부 플랜지 하부에 바닥시스템이 위치하여 전통적인 공법에 비해 층고절감의 효과와 최적단면으로 설계시 공기의 단축과 비용의 절감은 물론 물량의 감소를 기대 할 수 있다. 그러나 단면은 기존 H형강 보와 달리 상하 비대칭으로 중립축의 위치가 중앙에 위치하지 않기 때문에 상하연단에 대한 단면계수가 같지 않게 된다. 이에 따른 상하플랜지 판요소의 두께비에 따른 매개 변수적 분석이 요구된다. 따라서, 본 연구에서는 단면의 상부 플랜지 두께에 대한 하부 플랜지 두께의 비에 따른 중립축위치, 단면계수의 변화추이를 분석하여 최적단면을 도출하는데 주목적을 두었다.

• 한국표면공학회지
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• 제40권6호
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• pp.262-270
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• 2007

Recently, there has been a new appreciation of aluminum alloys as materials that are capable of reducing the environment load. This is because aluminum alloys are lightweight, easy to recycle, permit miniaturization, and have environmental friendly properties. In this study, we investigated the mechanical and electrochemical properties of 5083F aluminum alloys using slow strain rate test(SSRT) and potentiostatic tests under various potential conditions. In the potentiostatic tests, the current density in the potential range from -0.7 to -1.4V after 1,200 s was low. After considering the results of the potentiostatic tests, maximum tensile strength, yield strength, elongation, time-to-fracture, observation of fractured specimen and fractography analysis, the optimum protection potential range was between -1.3 and -0.7V(Ag/AgCl).

• KIEAE Journal
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• 제2권3호
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• pp.63-70
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• 2002

This study aims to provide the fundamental date of HUANGTO GUDUL for applying to current house heating system. It has been used as a traditional heating system in Korea for a long time and disappeared in the course of industrialization in Korea last a few decades and these days is tend to be widely adopted as house heating system. Even though it is known that the traditional heating system of HUANGTO GUDUL is good for ecological environment house and a kind of the natural friendly heating system for optimum residential heating environment, there are few systematic researches and analysed data of it. In order to analyse the characteristics of HUANGTO GUDUL, the existing materials of it's historical change was studied. And the architectural prospects of the use of GUDUL on the point of view of environmental ecology. The data of relationship between the mechanic properties and the workability of GUDUL materials and the environmental index such as the heating environment, relative humidity, and deodorization ratio and so on. And the heating effectiveness of GUDUL was compared with existing modem materials by experimental analysis. The results stated above can be grafted architecture and will be offered the optimum heating environment.

• 한국자동차공학회논문집
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• 제1권2호
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• pp.103-116
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• 1993

Recently, engineering ceramics called as the 3 material have been concerned significantly with some excellent mechanical properties and many functions as new materials for high precision mechanical components and engineering parts for at large. Then, for designing engineering parts using engineering ceramics, bending strength value data with high reliability is more essential than any other mechanical properties. But, because of brittleness and structural characteristic, it is very hard to grind with conventional tools, and the generation of cracks and various defects of engineering ceramics parts during grinding machining process are serious problems. Thus, in present study, surface grinding experiments with various machining conditions using resin bond diamond wheels are carried out to obtain the most excellent guality of testpiece surface and optimum step of grinding process for the high efficient stock removal rate to save running time. As the results from grinding experiments and 3-points bending strength test of ground Al2O3 ceramics parts on Korean Standard, manufactured in our country and Japan, basic technology and know-how to develop the optimum grinding machining conditions and also high bending strength values with high reliability are obtained.

• 한국농공학회지
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• 제15권1호
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• pp.2904-2912
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• 1973

The density of soil is one of the most important of its engineering properties, and many soil-engineering operations directed toward improving the density characteristics of matecal. This report is a study on relationship between density, permiabilty and other physical properties of compacted soil in various desity grades. The results of the study can be summariged as follow: 1. The optimum moisture content of soil increses with increasing of fine particles and a relationship between both parameter is $w_0=0.1765.n$ Where, n is passing percentage from #200 sieve. 2. The porosity of soil increases with increasing of optimum water content as $e=aw_0+b$ without having relation to compaction ratio. 3. The increment of permeability of soil is high when the compaction ratio is increased and the phenomenon is conspicuous in case of course soil and non-plastic soil. 4. The permeability of soil decreases with increasing of optrimum water content and the phenomenon is conspicuous when compaction ratio decreases. And the permeability is almost constant when optimum water content is more than 25 percent, even though compaction ratio changes. 5. The permeablity of soil increanses when the amount of fine particles is very few, the permeability is almost constant as being impervious condition without having relation to compaction ratio when there in more than 90 percent of fine particles(less than #200 sieve).

• 한국진공학회지
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• 제8권3A호
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• pp.194-200
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• 1999

In this paper studied was the piezoelectric properties of the $\beta$-PVDF organic thin films prepared by physical vapour deposition method. The molecular orientation of organic thin films was controlled by the application of an electric field and variation of substrate temperature during the evaporation process. Optimum conditions of manufacturing $\beta$-PVDF organic thin film by physical vapor deposition method is to keep at the substrate temperature of $80^{\circ}C$, at the applied electric field of 142.8 kV/cm. The voltage output coefficient increased from 1.39 to 7.04V increasing the force moment.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2009년도 제38회 동계학술대회 초록집
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• pp.225-225
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• 2010

In this study, the optimum structure of a magnetic thin film inductor was designed for application of DC-DC converters. The $Ni_{81}Fe_{19}$ (at%) alloy was selected as a high-frequency($\geq$ MHz) magnetic thin film core material and deposited on various substrates (bare Si, $SiO_2$ coated Si) using a high vacuum RF magnetron sputtering system. As-deposited NiFe thin films show similar magnetic properties compared to bulk NiFe alloys, indicating that they have a good film quality. The optimum design of solenoid-type magnetic thin film inductors was performed utilizing a Maxwell computer simulator (Ansoft HFSS V7.0 for PC) and parameters obtained from the magnetic properties of magnetic core materials selected. The high-frequency characteristics of the inductance(L) and quality factor(Q) obtained for the designed inductors through simulation agreed well with those obtained by theoretical calculations, confirming that the simulated result is realistic. The optimum structure of high-performance ($Q{\geq}60$, $L\;=\;1{\mu}H$, efficiency${\geq}90%$), high-frequency (${\geq}5MHz$), and solenoid-type magnetic thin film inductors was designed successfully.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 학회창립 10주년 기념 1999년도 가을 학술발표회 논문집
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• pp.127-130
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• 1999

Physical properties and microstructure of slag blended cement were investigated to evaluate the influence of sulphates and chlorides. The compressive strength developed as high chloride content dust and gypsum added and accordingly the microstructure modification was showed. The deviation of pore size distribution and hydrates was also observed. From these results we discussed optimum condition of gypsum and high chloride content dust leading to physical properties in this study.

• 한국세라믹학회지
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• 제12권2호
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• pp.3-9
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• 1975

The continuous grading method of pyrophyllite particles was adopted to prepare the refractories for ladle. The optimum conditions of fabrication adjusting the binders, the amount of water, the forming pressure and the firing temperature were investigated. The various properties, such as strength, density, porosity, thermal shock, corrosion resistance to slag were measured and compared with properties of ladle bricks presently used at local steel plants. The specimen studied in the present investigation showed a rather superior properties to theconventional product available locally.