• 한국건축시공학회지
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• 제18권3호
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• pp.259-266
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• 2018

최근, 건설현장에서는 콘크리트의 거푸집 해체 및 존치기간을 단축하기 위해서는 5MPa의 강도발현이 조기실현 되어야 한다. 한편, 국내의 온도분포를 분석하면 춘/추절기 및 동절기(급열양생 조건)의 경우 양생 온도가 $10^{\circ}C$ 안팎으로 형성되어 콘크리트의 양생에는 매우 열악한 조건이라고 할 수 있으며, 전체 공기에 미치는 영향이 매우 크므로 이를 고려한 콘크리트 품질관리 기술의 요구가 증대되고 있는 현실이다. 이에 콘크리트의 5MPa의 조기강도 발현을 위하여 배합측면에서 W/B의 저하, 단위 시멘트량의 증가 또는 시멘트 분말도의 증가, 고성능 감수제의 사용 등을 고려한 방법들이 주로 검토되고 있으나, 지역적 공급제한, 경제성 등에 의한 실용화가 일부 제한적으로 실시되고 있다. 본 연구에서는 실제 현장의 골조공사에 주로 활용되고 있는 설계기준강도 21~27MPa 범위의 콘크리트를 대상으로 $10^{\circ}C$ 온도조건의 범위에서 단위 시멘트량, 혼화제의 변경에 따른 물성, 강도발현 등을 검토함으로서 거푸집 탈형시기를 분석해보고자 하였다. 실험결과, 일반형 혼화제를 사용한 상태에서 단위 시멘트량 $360kg/m^3$까지 증가하여도 36시간까지 5MPa를 확보할 수 없는 것으로 나타났으며, 결합재 치환을 실시하는 경우에는 48시간에도 5MPa 확보가 어려운 것으로 확인되었다. 또한, 혼화제의 종류에 따라서는 조강형 PC를 사용하는 경우 강도개선율이 우수한 것으로 확인되었으며, 적산온도 평가 결과 5 MPa 발현시기가 30시간으로 추정되었다. 따라서 현장의 배합설계 있어서는 단위시멘트량은 $330kg/m^3$를 기준으로 조강 혼화제의 사용 또는 조강제의 개선에 따른 검토가 이루어져야 할 것으로 판단되었다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회B
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• pp.1916-1919
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• 2007

We have been setting up experiments on propagation of shock waves generated by the pulsed laser ablation. One side of a thin metal foil is subjected to laser ablation as a shock wave propagates through the foil. The shock wave, which penetrates through the foil is reflected by an acoustic impedance which causes the metal foil to high-strain rate deform. This short time physics is captured on an ICCD camera. The focus of our research is applying shock wave and deformation of the thin foil from the ablation to accelerating micro-particles to a very high speed.

• 산학경영연구
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• 제9권
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• pp.99-121
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• 1996

On the job training is useful : a part of on the job training has increased the marginal productivity of future and rate of wage. Investment in a human capital depends on character of investment and market conditions. The innovation role of small and medium firms has recently received increasing attention in newly industrializing countries as they attempt to transform their industries from labor intensive to technology intensive. It also suggests some implications to the small and medium firms' strategies and public policies accelerating research and development. Lack of qualified scientists and engineers often inhibits the small and medium firms' ability to access and assimilate external technical information. Such technical personnel are particularly scarce in NICs. Therefore, how to employ these technical staff should be an important issue for small and medium firms seeking to acquire distinctive competences. Small and medium firms must invest further education and training to its labor.

• International Journal of Automotive Technology
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• 제5권4호
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• pp.311-319
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• 2004

There are many methods to test engine emissions depending on the regulations used such as FTP-75(CYS-75) mode, 10-15 mode and ECE-15 mode. Most of these modes consist of transient conditions such as cranking, rapid acceleration or deceleration modes. In this experimental research, the transient characteristics including cranking and accelerating mode in SI engines were studied to compare pure gasoline with methanol-reformulated fuels for performance and exhaust emissions. The results show that methanol-reformulated fuels have a better emissions reduction rate than that of pure gasoline especially for HC, CO and NOx emissions during cranking mode. The acceleration performances conform to the results of the distillation curve and the CO concentration for RM50 varies slightly in acceleration mode.

• 기술사
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• 제43권6호
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• pp.39-45
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• 2010

Soil plays a huge role in climate change, because even a tiny loss of 0.1% of carbon emitted into the atmosphere from European soils is the equivalent to the carbon emission of 100million extra cars on Europe's roads - an increase of about half of the existing car fleet. Soils contain around twice the amount of carbon in the atmosphere and three times the amount to be found in vegetation. Europe's soils are an enormous carbon reservoir, containing around 75billion tonnes, and poor management can have serious consequences. Soil degradation is accelerating across the EU, with negative effects on human health, ecosystems and climate change - and on economic prosperity and quality of life. Climate change is identified as a common element in many soil threats. Europe's soils urgently need better protection. The current trend of soil degradation needs to be reversed, and soil management practices must be improved if a high rate of soil carbon sequestration is to be achieved.

• Journal of Nutrition and Health
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• 제9권4호
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• pp.54-58
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• 1976

Vitamin C의 변화는 식품의 가치를 판단하는데 중요한 인자가 된다. 이의 변화는 산소의 존재하에서 일차반응 속도로 분해된다고 알려져 있다. 그러나 제한된 량의 산소 속에서는 이차반응 내지 일차반응으로 설명되기도 한다. 이에 제한된 산소속에서 철, 구리 이온의 존재하에서 관찰한 바 용존산소와는 크게 관계없이 일차 반응속도로 분해되었고 이때 빛의 조사는 촉진적인 인자였었다.

• 정보관리학회지
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• 제14권1호
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• pp.5-26
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• 1997

정보환경의 급속한 변화로 정보조직과 접근, 처리 및 이용에 새로운 체제변환이 필연적으로 대두됨에 따라 전문문헌정보센터의 전략적인 계획수립이 시급한 상황이다. 본 연구에서는 전문문헌정보센터의 전략적 계획수립을 위한 이론과 방법론을 제시하기 위하여 첫째, 전략적 계획에 대한 개념과 연구동향 분석을 통하여 계획수립의 개념적 틀을 제시하며, 둘째 전략적 계획수립의 단계별 과정에 대한 분석기법과 그 적용사례를 제시하며, 마지막으로 전략적 계획에 대한 이론과 사례를 근거로 21세기 전문문헌정보센터의 역할과 기능을 효율적으로 수행할 수 있는 전략적 계획모형을 제시하고자 한다.

• 한국안전학회지
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• 제13권4호
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• pp.180-185
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• 1998

The evaluation of thermal and pressure hazard of chemicals on the manufacturing, transporting and storaging is important in the chemical industry for safety. In this study, the thermal decomposition characteristics of intermediate of Saccharin were investigated by using Accelerating Rate Calorimeter(ARC) and Differential Scanning Calorimeter(DSC). Experimental results showed that decomposition temperatures in p-TSA were about 280~$318^{\circ}C$ by DSC and $201^{\circ}C$ by ARC. In case of o-TSA were about $336^{\circ}C$~$360.8^{\circ}C$ by DSC and $299^{\circ}C$ by ARC. The decomposition temperature acquired by ARC was about $70^{\circ}C$ lower than that by DSC. The exothermic runaway reaction in case of p-TSA occured in 598 minute and o-TSA in 5 minute. For the safety in the chemical industry, we should consider the ARC data as well as DSC data in the handling and design of process.

• 보건행정학회지
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• 제28권2호
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• pp.105-106
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• 2018

Korea, which entered the aged society in 2018, is accelerating the progress of the aged society due to the rapid decrease in birth. Although the low birth rate is the important issue, comprehensive measures to cope with the aged society should be established. In particular, the reform of the healthcare system in response to the aged society is very urgent. The reorganization of the healthcare system in response to the aged society should focus on improving the functional abilities of the elderly and should be transformed into integrated older person-centered health service. The benefit package of National Health Insurance should be diversified and appropriate payment of each benefit package should be applied. The ageism should be overcame, and it is important to recognize that the measures for the older person are investments in future society. The reform of healthcare system for older person are very urgent in Korea, which is advancing into a rapidly aged society.

• 대한전자공학회:학술대회논문집
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• 대한전자공학회 2008년도 하계종합학술대회
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• pp.761-762
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• 2008

This paper presents a hardware accelerator for accelerating vector graphics applications based on the OpenVG standard. Since our design mainly targets embedded applications, we focus on efficient uses of limited resources, especially the memory bandwidth. The designed accelerator can process the images of $640{\times}240$ pixels with moderate complexity at the rate of 30 frames per second.