• Journal of the Korean Institute of Gas
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• v.18 no.3
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• pp.20-30
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• 2014

To develop a unconventional gas reservoir, an analysis of tight rock property are required. Especially, conventional measurements are difficult to be applied to unconventional resources such as tight gas reservoir because the permeability are extremely low compared to a conventional gas reservoir. In this study, an apparatus was developed for measuring low permeability and porosity based on a pressure pulse decay method under unsteady state conditions. The apparatus was applied for measuring the porosity and permeability of tight sand core samples from Gyeongsang basin in Korea. As a validation of the measurement, regression analysis was carried out using the dimensionless pseudo-pressure between the measured data and analytical solution. The results show the correlation coefficients above 0.96. Therefore, it is believed that the apparatus has a high accuracy.

• Tunnel and Underground Space
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• v.21 no.3
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• pp.205-215
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• 2011

In this study, we analyzed physical properties of granites and their correlation with rock mass classification methods. The granite samples were obtained from field survey, in-situ borehole tests and laboratory tests for a design phase of various roads, railways and other civil engineering works in Korea. Among the measured physical properties, the results of unit weight, compressive strength, tensile strength, seismic velocity, cohesion, friction angle, elastic modulus and deformation modulus were introduced. We also correlated these properties with the compressive strength. The results of different rock classification method of RQD, RMR, and Q-system against the granites in Korea were compared with each other, and the correlation equations were proposed in a more simplified form. We also derived RMR values using the compressive strength as well as the RQD values of in-situ drilled cores, and estimated the deformation modulus of in-situ rock mass in terms of the RMR values.

• Proceedings of the Korean Institute of Surface Engineering Conference
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• 2016.11a
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• pp.155-155
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• 2016

DLC (Diamond like Carbon)는 Diamond와 유사한 물리화학적 특성을 보유한 막으로 고경도 및 우수한 내마모성, 화학적 안정성의 특성을 가지고 있다. DLC는 크게 카본의 막 형성 공정에서 카본 소스에 따라 수소가 포함된 DLC와 무수소 DLC 로 구분된다. Tetrahedral amorphous carbon (ta-C) 박막은 DLC 박막 중에서 가장 다이아몬드와 유사한 특성을 가지는 박막으로, a:C-H에 비해 고온안정성, 높은 경도 (30~80 GPa) 및 내마모 특성이 우수하여, 현재 다양한 응용분야에 적용되고 있으며, 최근에는 고내구성을 보유하면서 전기적 특성을 가지는 기능성 DLC막의 요구가 증대하고 있다. 본 연구에서는 무수소 DLC 형성을 위해 자장필터가 장착된 Filtered Vacuum Arc Source (FVAS)를 자체적으로 개발하여 연구를 수행하였다. FVAS 장비는 카본 이온 발생부와 Plasma Duct 부위, 전자석부위 구성되어 있으며, 본 연구에서는 Plasma Duct 부위의 Bias 제어를 통한 음극에서 기판으로 이동하는 카본이온의 에너지 및 flux 변화를 통해 ta-C 막의 전기적, 기계적 물성 연구를 진행하였다. Plasma Duct Bias 변화는 각 0 ~ 20 V 조건으로 진행하였으며, 물성 평가는 경도 (Hardness), 마찰계수, 전기적 특성에 대한 분석을 진행하였다. 박막의 증착 거동에서는 Plasma Duct bias 변화에 따라 10 V에서 가장 높은 증착 거동을 가지다 감소하는 경향을 확인 하였으며, 박막의 물성 특성 평가 시에도 이와 유사하게 특성의 차이를 관찰하였다. 이는 음극부위에서 형성된 카본이온이 기판에 도달 시에 Plasma Duct Bias 변화에 따라 이온의 Flux 및 에너지 변화로 인한 박막의 밀도 및 ta-C 막의 물성 변화로 예상되며, 이를 분석하기 위해 라만 분석법을 통해 증명하였다.

• Composites Research
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• v.35 no.2
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• pp.69-74
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• 2022

In this study, the conductive paste used in a wide range such as wiring in the electronic packaging field, the automobile industry, and electronic products is manufactured under various process conditions due to the simplicity of the process, and then the thermal, mechanical, and electrical characteristics are analyzed and simulation studies are conducted to optimize the process. to establish the conditions of the conductive paste manufacturing process. First, a conductive paste was prepared by setting various types of binder resin, an essential component of the conductive paste, and characteristics such as thermal conductivity, tensile strength, and elongation were analyzed. Among the binder resins, the conductive paste applied with a flexible epoxy material had the best physical properties, and a simulation study was conducted based on the physical property data base of the conductive face. As a result of the simulation, the best physical properties were exhibited when the Ag flake volume fraction was 60%.

• 한국신재생에너지학회:학술대회논문집
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• 2008.05a
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• pp.646-649
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• 2008

최근 유가 폭등으로 관심이 고조되고 있는 청정 재생에너지인 지열자원의 효과적인 개발 및 활용을 위하여 그동안 축적된 지열조사 및 연구정보를 체계적으로 저장,관리, 도시할 수 있는GIS기반의 지열자원 정보시스템을 개발하고자 하였다. 이를 위하여 열물성, 지온경사, 지열류량, 열생산율, 열부존량 등 지열조사 자료를 수집 및 분석하여 공간적 특성과 역할에 따라 기본정보, 참조정보, 분석정보, 부가정보의 4개 자료군, 39개 단위데이터로 분류하였고, 각 단위데이터의 속성 선정과 연계를 위한 GIS 데이터 모델링을 통하여 공간데이터베이스를 설계하였다. 지열자원 정보시스템은 도면표시, 자료조회, 분석/통계등 전반적인 GIS 기능을 이용하여 지열자료의 조회 및 분석이 용이하도록 설계하였다.

• Proceedings of the Korean Society of Propulsion Engineers Conference
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• 1996.11a
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• pp.3-11
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• 1996

본 연구는 고체 추진기관의 각종 밀봉 부에 많이 사용되는 O-링의 설계시 고려되는 각종 형상인자의 변화에 따른 O-링의 거동과 응력 상태를 분석하여 설계 최적조건을 찾기 위한 내용을 다루고 있다. 조립 부의 내외경과 조립 공차, 챔퍼길이와 각도, 조립 홈의 외경, 깊이, 폭, 구성반경, O-링의 내경과 선 직경 등의 설계 변수에 의한 조립부 형상과 재료의 물성치, 유한요소 선택 및 요소 분할, 경계조건, 하중조건, 접촉부 정의 등을 MSC/PATRAN3의 $PCL^{[1]}$/로 프로그래밍 하여 설계변수에 의한 결과 분석을 손쉽게 수행할 수 있도록 시도하였다 고무의 Hyperelastic 물성치는 문헌상의 자료$자료^{[2]}$에 제시된 Ogden 상수를 사용하였으며 추후에는 인장시험, 순수전단시험, 이 축 인장시험을 통해 실험적으로 측정$^{[3]}$ 하여 적용할 예정이다. 고무의 대변형, 대 변형률을 고려한 비선형 응력해석은 MSC/PATRAN3의 Advanced FEA 모듈과 ABAQUS 5.5를 사용하였다. 본 연구에서의 해석결과를 설계변수들의 영향을 비교 분석하는데 사용하였으나 그 정확도가 입증된 상태는 아니며 추후 실제 조립 및 수압시험을 통해 평가할 예정이다.

• Analytical Science and Technology
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• v.6 no.2
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• pp.231-238
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• 1993

The thermal behavior of binder in multi-layer actuator has an effect on the properties of actuator. Binder burn-out process and thermal degradation mechanism of PNN-PZT/Acrylic binder were analyzed by FTIR, DSC, TGA. Binder was burnt out by two step. In oxygen atomsphere, thermal degradation was activated and final residue was minimized to 5%.

• Analytical Science and Technology
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• v.19 no.6
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• pp.504-511
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• 2006

Polysilanes with organic substituents such as methyl and phenyl were synthesized by Wurtz dechlorination-condensation reactions using ultrasonic from organochlorosilanes. The yields were compared with the results of thermal dechlorination-condensation reactions. Properties such as thermogravimetric analysis and photoreactivity were investigated for the possibility of applications.

• Journal of Advanced Marine Engineering and Technology
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• v.41 no.3
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• pp.269-275
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• 2017

Shipwreck remains below the seabed not only effect the ocean currents and tides, but influence the physical properties of sediments and sedimentary environments that comprise the seabed. In particular, the influence of local shipwrecks discovered buried in the seabed on the sediment is visible. In this study, sediments were collected from the surrounding area of Taean Mado No.3 shipwreck using grab samplers and vibro-corers. The physical properties of these sediments were analyzed to evaluate the impact of the Taean Mado shipwreck No.3 remains. Sediment core analysis by means of density and ultrasonic velocity showed that shear strength tended to increase with depth, whereas moisture content and porosity tended to decrease with depth. Grain size analysis results are shown in terms of Folk's classification, where the grain size of the core samples in the study area indicate mud or sandy mud, and that of the grab sample indicates a muddy sand. Results of the sedimentation rate analysis indicate a rate of 2.84 cm/year and carbon dating of the 150 cm deep seashell indicates the Neolithic age. These sediments were analyzed for the study of the relationship between the Taean Mado shipwreck No.3 remains and the physical properties of the sediment.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.40 no.11
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• pp.697-704
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• 2016

Coal modified by acid treatment was investigated to analyze the correlation between the cell performance and electrochemical parameters in a direct carbon fuel cell (DCFC). The fuels were subjected to thermogravimetry analysis, gas adsorption test, and X-ray photoelectron spectroscopy to investigate the fuel properties and surface characteristics. After the treatment of raw coal, the thermal reactivity of the treated fuels increased, and the specific surface area decreased, though the mean pore diameters of three fuels were similar. The coal treated by $HNO_3$ showed the highest ratio of oxygen to carbon, and also an increase in the surface oxygen groups on the fuel surface. Through comparison between the fuel surface properties and electrochemical performance, it was confirmed that the surface oxygen groups have an influence on the improvement in the DCFC performance.