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나노인덴테이션 주사탐침현미경에 의한 다이아몬드성 탄소 박막의 특성 분석
김봉섭,오영우,윤존도 경남대학교 신소재연구소 2001 신소재연구 Vol.13 No.-
나노인덴테이션(Nanoindentation) 방법에 의한 박막재료의 기계적 특성을 평가하기 위하여, 용융석영과 (111)n형 실리콘웨이퍼를 이용하여 탄성계수와 경도를 측정하고, 그 값을 문헌 상의 값과 비교하였다. 용융석영은 2%, (111)n형 실리콘웨이퍼는 10%범위 내에서 잘 일치하였다. 이온빔증착법으로 제조된 400∼500nm의 두께를 가지는 DLC 박막을 40∼50nm 깊이로 압입 시험을 실시하였다. 그 결과 5가지 박막 중에서, 중착가스로 벤젠만 사용하고 바이어스 전압을 0∼-50V로 하여 제조한 박막의 탄성계수와 경도가 132GPa과 18GPa로 가장 높게 나타났다. 주사탐침현미경을 이용하여 표면 거칠기를 측정한 결과 순수그룹의 표면 거칠기는 0.25nm이하로 매우 평탄한 표면을 가지고 있었지만, 실리콘그룹은 1.17nm에서 2.60nm로 실란이 첨가된 모든 시편에서 물결무늬 모양이 관찰되었으며, 표면 거칠기가 증가하였다. In order for the characterization of mechanical properties of thin film materials, the hardness and elastic modulus of fused-quartz and (111)n type silicon safer was measured by nanoindentation. The results are compared with the value of reference. The measured hardness and elastic modulus was within 2% of fused-quartz and 10% of (111)n type silicon wafer. Ion beam deposited DLC thin films, with a thickness of 400∼500nm were indented in a depth range of 40∼50nm by nanoindentation. The results showed that DLC thin film using benzene and bias voltage 0∼-50V has elastic modulus and hardness value of 132GPa and 18GPa. Surface roughness of DLC thin films was measured by scanning probe microscope. The results showed that pure group had a very low roughness within 0.25nm and the roughness of silicon group was within 1.17 and 2.60nm. All of silicon doped samples showed wavy surface.
나노인덴테이션과 주사탐침현미경을 이용한 박막 재료의 특성평가
김봉섭,윤존도,김종국,Kim, Bong-seob,Yun, Jon-do,Kim, Jong-kuk 한국재료학회 2003 한국재료학회지 Vol.13 No.9
Surface and mechanical properties of thin films with submicron thickness was characterized by nanoindentation with Berkovich and Vickers tips, and scanning probe microscopy. Nanoindention was made in a depth range of 15 to 200 nm from the surface by applying tiny force in a range from 150 to $9,000 \mu$N. Stiffness, contact area, hardness, and elastic modulus were determined from the force-displacement curve obtained. Reliability was first tested by using fused quartz, a standard sample. Elastic modulus and hardness values of fused quartz measured were the same as those reported in the literature within two percent of error. Mechanical properties of ITO thin film were characterized in a depth range of 15∼200nm. As indentation depth increased, elastic modulus and hardness decreased by substrate effect. Ion beam deposited DLC thin films were indented in a depth range of 40∼50 nm. The results showed that the DLC thin film using benzene and bias voltage 0∼-50 V has elastic modulus and hardness value of 132 and 18 GPa respectively. Pure DLC thin films showed roughnesses lower than 0.25 nm, but silicon-added DLC thin films showed much higher roughness values, and the wavy surface morphology.
고령층 디지털 사회 자본에 대한 디지털 조력자 영향 연구: 디지털 정보 활용의 매개효과를 중심으로
김봉섭,고정현 경북대학교 사회과학연구원 2020 사회과학 담론과 정책 Vol.13 No.2
This study aims to empirically investigate the influence and effect of social factors as the cause and effect of digital usage for the elderly. First, the role of digital supporter as a new influencing factor on digital usage for the elderly is examined. In addition, this study is to be confirmed whether or not digital social capital with positive effects derived from digital usage for the elderly is expanded. To this end, data from the <2019 The report of Digital Divide> by the National Information Society Agency were used. The data used for the analysis were responses from 1,088 Internet users among the elderly aged 60 or older. As a result of the analysis, it was confirmed that external digital supporter, such as friends, acquaintances, and external experts, have a positive influence on digital usage for the elderly, rather than internal digital supporter such as family. In addition, it was found that digital usage for the elderly contributed positively to the expansion of digital social capital in two types, such as the bonding and the bridging. Finally, external digital supporter confirmed the path that positively affects digital social capital through digital usage for the elderly. Accordingly, it seems necessary to prepare measure to secure various social support sources within the local community in order to bridge the digital divide and enhance information usage for the elderly in the future. In addition, it is the significance of this study to confirm that the digital divide is not a problem of the difference between the class that uses information and the class who does not use it, but a factor that causes substantial problems such as expansion of social capital. 본 연구는 고령층 디지털 정보 활용의 원인과 결과로 사회적 요인의 영향과 효과를 실증적으로 규명하고자 한다. 먼저, 영향 요인으로 디지털 조력자의 역할을 살펴보고, 정보 활용의 결과로 디지털 사회 자본의 확충 여부를 확인하고자 한다. 이를 위해, <2019 디지털 정보격차 실태조사>의 60세 이상 인터넷 이용자 1,088명의 데이터를 활용했다. 분석 결과, 고령층의 정보 활용은 가족 등 내부 디지털 조력자 보다는 친구, 지인 등 외부 디지털 조력자가 긍정적인 영향을 미치고 있으며, 정보 활용은 결속형과 교량형 등 두 가지 유형의 디지털 사회자본 확충에 기여하는 것으로 나타났다. 마지막으로 디지털 조력자와 디지털 사회자본 간의 관계에서 고령층 디지털 정보 활용의 매개효과를 확인했다. 이에 따라, 향후 지역 사회 내에서 다양한 사회적 지지원 확보를 위한 정책 마련이 필요해 보인다. 또한, 정보격차가 사회자본 확충과 같은 실체적 효과를 낳는 요인임을 확인한 것은 본 연구의 의의라 할 수 있다.
붉은대게 폐각으로부터 키토산의 제조 및 물리화학적 특성
김봉섭,박광식,주옥수,서명교,허종화 한국환경보건학회 2001 한국환경보건학회지 Vol.27 No.1
Chitosans were prepared from red crab chitin under various alkali treatment conditions(different alkali concentrations, reaction times and temperatures) and theirphysicochemical properties were investigated. The nitrogen content and deacetylation degree of red crab chitin were 6.15% and 22.17A%, respectively. By the IR spectra, red crab and reference chitin showed the sharp bands at 1650 CM-1/ and 1550 CM-1/, which are characteristic of chitin. The nitrogen contents of prepared chitosans ranged from 6.19~7.48%. Thedeacetylation degree was increased from 63~76% and 48~78% with increasing reaction time and temperature, whereas viscosity was decreased. The nitrogen content and yield of red crab chitosan perpared from chitin with 50% NaOH, 1:25(w/v) for 3.0 hr at 120CM-1 / were 7.26% and 85.0%, respectively. and viscosity, deacetylation degree and molecular weight, 67.0 mPa.s, 75.0% and 6.5x105 Dalton, respectively. From the IR spectra, the amide absorption bands of red crab and reference chitosan became very weak, similarly. And at solid state 13C-NMR spectra, C=O(carbonyl carbon) signals absent, whereas CH3(methyl carbon) was residues. Chemical shift of 13C-NMR spectra of red crab and reference chitosans were in good agreement with slight experimental deviation.