• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.581-584
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• 2008

Generally, durability of concrete structures under marine environment is grossly declined by detrimental ions such as chlorides, which penetrate concrete and was diffused to corrode reinforcing rod. Therefore, chloride diffusion properties in concrete are important for durability evaluation and design of concrete structure. For estimation of chloride diffusion coefficient in concrete, both evaluation methods are used for steady state and non-steady state derived from Fick's 1st and 2nd law, respectively. However, as it is very difficult to evaluate diffusion coefficient for non-steady state like service environment where concrete is actually exposed, indirect evaluation method by laboratory accelerated test is generally used. In this study, comparison of chloride diffusion behavior was investigated for fixed mix proportion and age of concrete using four accelerated test methods based on domestic and foreign standards. From test results, only relative comparison between concrete mixtures was possible using ASTM C 1202 test, and diffusion coefficient for steady state was estimated as low as 1/10 of that for non-steady state. In addition, diffusion coefficient estimated by immersion test was similar to result by NT build 492 test.

• Korean Journal of Materials Research
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• v.17 no.9
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• pp.469-474
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• 2007

Electroless deposition(ELD) was applied to fabricate Cu interconnections on a TaN diffusion barrier with Pd seed layer. The Pd seed layer was obtained by self-assembled monolayer method(SAM) with PDDA and PSS as surfactants. We were able to obtain about 10nm Pd nano particles as seeds for electroless Cu deposition and the density of Pd seeds was much higher than that of Pd seeds fabricated by conventional Pd sensitization-activation method. Also we were able to obtain finer Cu interconnections by ELD. Therefore we concluded that the Pd seed layer by SAM was able to be applied to form Cu interconnection by ELD for under 30nm feature.

• Korean Journal of Materials Research
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• v.1 no.4
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• pp.191-197
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• 1991

The surface roughnesses of titanium silicide films and the diffusion behaviours of dopants in single crystal and polycrystalline silicon substrates durng titanium silicide formation by rapid thermal annealing(RTA) of sputter deposited Ti-filicide film from the composite $TiSi_{2.6}$ target were investigated by the secondary ion mass spectrometry(SIMS), a four-point probe, X-ray diffraction, and surface roughness measurements. The as-deposited films were amorphous but film prepared on single silicon substrate crystallized to the orthorhombic $TiSi_2$(C54 structure) upon rapid thermal annealing(RTA) at $800^{\circ}C$ for 20sec. There was no significant out-diffusion of dopants from both single crystal and polycrystalline silicon substrate into titanum silicide layers during annealing. Most of the implanted dopants piled up near the titanium silicide/silicon interface. The surface roughnesses of titanium silicide films were in the range between 16 and 22nm.

• Proceedings of the Korea Concrete Institute Conference
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• 2008.04a
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• pp.973-976
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• 2008

Recently, it is increasingly reported that the deterioration of concrete structure under marine environments is due to diffusion and penetration of chloride ions. It is very important to estimate the diffusion coefficient of chloride ion in concrete. Estimation methods of chloride diffusivity by concentration difference is time-consuming. Therefore, chloride diffusivity of concrete is mainly conducted by electrically accelerated method, which is accelerating the movement of chloride ion by potential difference. However, there has not been any proper method for field quality control to closely determine the diffusion coefficient of chloride ion through accelerated tests using potential difference. In this paper, the various test methods for determination of chloride diffusion coefficient in concrete were investigated through comparison accelerated tests. From the results of estimated diffusion coefficient of chloride ion, relationship between the ponding test and acceleration test was examined.

• Journal of Korean Library and Information Science Society
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• v.42 no.4
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• pp.331-351
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• 2011

This paper analyzes the activities and recommendations of W3C LLD Incubator group and investigates the benefits of Library Link Data through case studies. It also discusses the necessary global identification systems for developing useful LLD as well as the problems associated with linking available vocabularies with existing data sets. Ways to apply RDF, SKOS, Microformats, and RDFa to LLD are presented. the many challenges related to establishing LLD-based information services and the various barriers that prevent libraries from accepting LLD are also identified. Finally this paper presents a new LLD-based digital information system and provides some recommendations on how to promote and expand LLD in Korea.

• Proceedings of the Materials Research Society of Korea Conference
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• 2011.05a
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• pp.242.1-242.1
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• 2011

산화물 반도체는 높은 이동도와 낮은 공정 온도, 넓은 밴드갭으로 인한 투명성등 많은 장정을 가지고 있어 최근 많이 연구되고 있다. 그 중에서도 InGaZnO (IGZO)는 In, Ga 함유량으로 박막의 전기적 특성을 쉽게 조절할 수 있고 상온에서 비정질 상태로 증착되어 균일성에 장점이 있다. IGZO 박막을 TFT에 적용 시 MOSFET과는 다르게 축적 상태에서 채널이 형성되기 때문에 산화물 반도체 내에 캐리어 농도는 TFT 특성에 많은 영향을 미친다. 또한, 실리콘 기반의 트랜지스터는 이온 주입 및 확산 공정을 통해서 선택적으로 $10^{20}/cm^3$ 이상의 고농도 도핑을 실시하여 좋은 트랜지스터 특성을 확보할 수 있으나 IGZO 박막에는 이러한 접근이 불가능하다. 따라서 IGZO 박막의 캐리어 농도를 조절할 수 있으면 소스/드레인과 반도체의 접촉 저항 감소 및 전계 효과 이동도등 많은 특성을 개선할 수 있다. 본 연구에서는 UV light를 이용하여 IGZO 박막의 캐리어 농도를 조절하였다. IGZO 박막은 UV light 조사로 인해 Mo와 IGZO박막의 접촉저항이 $3{\times}10^3\;{\Omega}^*cm$에서 $1{\times}10^2\;{\Omega}^*cm$로 감소하였다. 이는 UV 조사로 표면에 금속-OH 결합이 생성되어 IGZO 박막의 캐리어 농도가 ${\sim}5{\times}10^{15}/cm^3$에서 ${\sim}3{\times}10^{17}/cm^3$까지 증가하기 때문이다. 또한 표면에 생성된 OH기는 강한 친수성 성질을 보여주고 표면의 높은 에너지 상태는 Self-Assembly Monolayer (SAM) 공정 적용이 가능 하다. 본 실험에서는 SAM 공정을 적용하여 IGZO-based TFT 제작에 성공하였고, 이 TFT는 UV 조사 시간에 따라 전계 효과 이동도가 0.03 $cm^2/Vs$에서 2.1 $cm^2/Vs$으로 100배 정도 증가하였다.

• Fire Science and Engineering
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• v.32 no.3
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• pp.76-87
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• 2018

This study describes the damage effects modeling for a quantitative prediction about the hazardous distances from pressurized chlorine saturated liquid tank, which has two-phase leakage. The heavy gas, chlorine is an accidental substance that is used as a raw material and intermediate in chemical plants. Based on the evaluation method for damage prediction and accident effects assessment models, the operating conditions were set as the standard conditions to reveal the optimal variables on an accident due to the leakage of a liquid chlorine storage vessel. A model of the atmospheric diffusion model, ALOHA (V5.4.4) developed by USEPA and NOAA, which is used for a risk assessment of Off-site Risk Assessment (ORA), was used. The Yeosu National Industrial Complex is designated as a model site, which manufactures and handles large quantities of chemical substances. Weather-related variables and process variables for each scenario need to be modelled to derive the characteristics of leakage accidents. The estimated levels of concern (LOC) were calculated based on the Gaussian diffusion model. As a result of ALOHA modeling, the hazardous distance due to chlorine diffusion increased with increasing air temperature and the wind speed decreased and the atmospheric stability was stabilized.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.21 no.1
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• pp.73-82
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• 1997

High temperature densification behaviors of alumina powder compacts were investigated under hot pressing and hot isostatic pressing. An alumina part of valve-head shape was fabricated under hot pressing and its forming process was simulated by finite element calculation. an alumina powder compact encapsulated by a stainless steel container was also densified under hot isostatic pressing. Inhomogeneous deformations during hot isostatic pressing due to the canning effect were observed experimentally and predicted by finite element analysis.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.1341-1344
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• 2007

최근에 노트북 컴퓨터의 가격 하락과 더불어 보급이 급속도로 확산되고 있다. 노트북 컴퓨터 간의 경쟁에서 얼마나 더 얇고 가볍게 만들 수 있는가는 가치 차별화의 근간이 된다. 따라서 노트북 컴퓨터의 박형화에서 HDD 나 ODD 같은 핵심 주변장치의 박형화는 핵심 이슈이다. 본 논문에서는 기존 노트북용 박형 광저장장치의 엑추에이터 개발에 있어서 보다 안정적인 제어가 될 수 있는 구조를 소개하고 엑추에이터의 실제 데이터를 이용하여 서보 제어에 있어서의 설계마진을 고찰해 보고자 한다.

• Proceedings of the Korean Statistical Society Conference
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• 2005.05a
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• pp.65-71
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• 2005

지역소득통계는 경제${\cdot}$사회${\cdot}$복지의 종합적인 지역정책 수립을 위한 핵심 자료로 이용되고 있다. 지역소득통계의 수준을 보다 높이기 위해서는 현재 작성하고 있는 생산 및 지출측면의 지역소득통계 뿐만 아니라 분배측면의 소득에 대한 통계도 함께 조속히 작성되어야 한다. 국민소득통계는 한국은행에서 작성하고 있으나 16개 시도별 지역내총생산(GRDP)통계는 통계청에서 별도 추계하여 작성하고 있다. 이에 지역내총생산(GRDP)과 국내총생산(GDP)의 상호간 차이를 최소화하기 위하여는 유기적인 협력관계가 필요하다. 또한 기초자치단체(시군구)별 지역내총생산(GRDP)통계는 시도에서 작성하고 있다. 현재 6개 시도에서 작성되고 있는 기초자치단체별GRDP의 작성 확산을 위한 노력과 아울러 이들 자료와 통계청에서 작성한 시도별 GRDP자료와의 정합성 유지방안에 대한 대책도 요구되고 있다.