• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2009년도 춘계 학술논문 발표대회 학계
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• pp.53-56
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• 2009

This study reviewed the characteristics of concrete made of performance improving mixture materials based on KOH as a means to resolve the problems of initial quality reduction that result in concretes with blast furnace slag powder. Summarizing the results, first as the characteristics of fresh concrete, liquidity was found to reduce in general with increased BS substitution ratio. Objective range of liquidity was not satisfied in all mixes according to the use of performance improving mixture materials. Air capacity was satisfied to the objective range in all mixes. As the characteristics of hardened concrete, while compressive strength showed a decreasing trend with increasing BS substitution ratio at early age, increasing trend was shown by the plain with increasing BS substitution ratio at later age. On the other hand, K1 and K2 were only effective among mixture materials at early age, but K1F30 showed excellent strength at both early and later ages.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 봄 학술발표회 논문집(I)
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• pp.40-45
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• 1999

This experimental study presents the strength properties of mortar using the blast-furnace slag sand. The mix disign of this study is based on the each three classes of unit water; (250, 275, 300)kg/㎥ and four classes of W/C; (45, 50, 55, 60)% and substitution rate(0, 25, 50, 75, 100)%. It gives following result. As W/C ratio increase, the strength is decrease. In case of mortar using air-cooled blast-furnace slag sand, the 3-days and 7-days compression strength is increase as substitution rate is higher. But in case of the mortar using the quenched blast-furnace slag sand, the compression strength is decrease as substitution rate is higher.

• 한국농공학회논문집
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• 제51권1호
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• pp.21-26
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• 2009

This study was performed to evaluate the physical and mechanical properties of concrete using waste activated carbon. Materials used were ordinary portlant cement, crushed coarse aggregate, natural fine aggregate, waste activated carbon, and superplasticizer. The substitution ratios of waste activated carbon were 0,1,2,3,4,5,6,7,8,9 and 10%. The unit weight was decreased and water absorption ratio was increased with increasing the waste activated carbon content, respectively. When the substitution ratio of waste activated carbon was 3%, compressive strength, flexural strength and dynamic modulus of elastisity were more higher than that of the ordinary portland cement (OPC), and it was decreased with increasing the waste activated carbon content, respectively. The most effective contents of waste activated carbon was 2% in performance and 4% in practical use Accordingly, waste activated carbon can be used for concrete material.

• 한국농공학회논문집
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• 제55권3호
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• pp.9-12
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• 2013

The pavement is generally used on the highways, local loads, roads for bicycle riding and neighborhood living facility such as parking lot, plaza, park and sports facilities. However, the pavement material that is usually used on the most of roads is impermeable asphalt-concrete and cement-concrete. If the pavement material is impermeable, many problems can be happened on the drainage facilities in the rainy season. Additionally, a lot of rainwater on the pavement surface cannot permeate to the underground and flows to the sewage ditch, stream and river, etc. If a lot of rainwater flows at once, the floods can be out along the streams and rivers. So, underground water can be exhausted. Micro organisms cannot live in the underground. Recently, many studies has been conducted to exploit the permeable concrete that has high performance permeability. However, it is required to develop the permeable concrete which has high strength and durability. In this study, permeable and strength tests were performed to investigate the permeable characteristics of porous concrete according to fine aggregate content and substitution ratio of blast furnace slag. In this test, crushed stones with 10~20 mm and sand with 5~10 mm were used as a coarse aggregate and a fine aggregate respectively. The substitution ratio of blast furnace slag to cement weight is 0 %, 15 %, and 30 %. The ratio of fine aggregate to total aggregate is 0 %, 18 %, and 35 %. As a result, permeability coefficient was decreased according to fine aggregate ratio of total aggregate. Compressive strength was also decreased according to substitution ratio of blast furnace slag.

• 생명과학회지
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• 제30권7호
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• pp.606-613
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• 2020

본 연구는 돼지 지방 대체제로 올리브유 겔 첨가 비율을 달리하여 제조한 저지방 돈육 패티의 이화학적 품질 특성을 검토하였다. 돈육 패티는 돼지 지방 20%(대조군, T0), 돼지 지방 15%와 올리브유 겔 5%(T1), 돼지 지방 10%와 올리브유 겔 10%(T2), 돼지 지방 5%와 올리브유 겔 15%(T3), 그리고 올리브유 겔 20%(T4)를 첨가하여 제조하였다. 올리브유 겔 첨가 비율에 따라 수분 함량은 증가하고, 지방 함량은 감소하였다. 가열 전후 돈육 패티의 명도(L^*)와 적색도(a^*)는 T0가 가장 높았으며, 가열 후 돈육 패티의 황색도는 T4가 가장 높았다. 올리브유 겔 대체 비율이 높을수록 보수력, 수분 보유율 및 지방 보유율은 증가하였고, 조리 감량, 직경 감소율 및 수축율은 유의하게 감소하였다. 경도, 탄력성 및 씹힘성은 T4가 가장 높았고, 응집성 및 검성은 T0가 가장 높았다. 콜레스테롤 함량은 T4가 가장 낮았으며, 대조군(T0)에 대한 감소율은 T1, T2, T3 및 T4가 각각 13.8%, 12.6%, 34.5% 및 49.0%였다. 포화지방산은 palmitic acid가 가장 높았고, 불포화지방산은 oleic acid가 가장 높았다. 돈육 패티의 불포화지방산은 올리브유 겔의 첨가 비율에 따라 증가하였다. 그러므로 돼지 지방을 올리브유 겔로 대체하면 이화학적 특성들이 향상되고, 콜레스테롤 함량이 감소하며, 지방산 조성이 개선된 육제품의 제조가 가능하다.

• 콘크리트학회논문집
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• 제17권4호
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• pp.613-620
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• 2005

순환골재를 구조체용 콘크리트에 이용하는 것은 품질관리 및 내구성에 대한 논란으로 활성화가 현실적으로 어려운 실정이다. 이 경우 상대적으로 요구되는 품질 수준이 낮은 콘크리트 2차 제품에 순환골재를 활용하는 것이 유력한 대안이 될 수 있지만 증기 양생시 순환골재 콘크리트의 특성에 대한 연구성과는 거의 없는 실정이다. 이에 본 연구에서는 순환골재의 콘크리트 2차 제품 적용성을 검토하기 위하여, 다양한 순환 굵은골재 및 순환 잔골재 치환율에 따라 증기양생 및 수중양생을 통하여 제작된 콘크리트의 압축강도, 휨강도, 쪼갬인장강도, 부착강도 실험을 실시하였다. 강도 실험결과 순환 굵은골재의 치환율이 증가함에 따라 강도가 약간 감소하는 결과를 보이고 있으며, 순환 잔골재를 $100\%$ 치환한 경우에는 증기양생 콘크리트의 강도특성 저하가 뚜렷이 나타났다. 순환 굵은골재의 치환율이 $50\%$인 경우에는 압축강도, 휨강도, 부착강도가 보통 콘크리트와 거의 같게 나타나 일반 콘크리트와 동일하게 적용할 수 있을 것으로 판단된다. 순환골재와 고로슬래그 시멘트를 사용한 증기양생 콘크리트의 경우 증기양생 후 7일 시점에서 증기양생 보통포틀랜드 시멘트 콘크리트에 비해 강도가 낮게 나타났다. 양생방법에 따른 순환골재 콘크리트의 역학적인 차이는 일반 콘크리트와 유사하게 나타나 실제 2차제품의 생산에 순환골재 적용이 가능한 것으로 나타났지만 최적의 치환율을 결정하기 위해서는 추가적인 연구가 필요한 것으로 판단된다.

• 한국건축시공학회지
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• 제4권3호
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• pp.133-141
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• 2004

The object of this study is to investigate experimentally the shear behavior of reinforced concrete beams using recycled coarse aggregate. At first, the specimens are manufactured for the compressive strength of 210kgf/$\textrm{cm}^2$ with recycled coarse aggregate ratio of 0%, 20%, 40%, 60%, 80%, 100%, respectively. From the results, Reinforced concrete beams using recycled coarse aggregate were made with recycled coarse aggregate ratio of 0%, 20%, 40%, 60%, 80%, with stirrups and recycled coarse aggregate ratio of 0%, 20%, 40% without stirrups. The results of crack pattern and failure mode, load-displacement curve(center point and load point) and load-steel curve(compressive, tensile, stirrup) were analysed. It is concluded from the test that the shear behavior of recycled concrete beams is determined to have similar behavior of normal concrete beams. Therefore, from this study the application of recycled concrete to concrete structures may be possible. But, for using the recycled concrete widely, it is expected that the more studies on quality control, substitution ratio and mix design related with recycled concrete are necessary.

• 한국자동차공학회논문집
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• 제16권3호
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• pp.172-178
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• 2008

An object of this study is to confirm performance characteristics of the vortex tube apparatus for substitution of the intercooler in a common-rail diesel engine. The turbo pressure, the intake air flow rate and the ${\Delta}T_c$ decrease ratio of the intercooler were measured in a experimental engine. The vortex tube apparatus was made after confirmation of the geometric phenomena in fundamental experiments. To investigate energy separation characteristics of the vortex tube, the measured turbo pressure was applied to the vortex tube inlet and the ${\Delta}T_c$ decrease ratio was compared with one of the intercooler in the cold air mass flow ratio similar to the intake air flow rate of the experimental engine. From the results, we found that the energy separation ratio is increased according to of the inlet pressure and the ${\Delta}T_c$ decrease ratio of the vortex tube apparatus is higher than one of the intercooler at low engine speed and engine load of medium and low.

• Genomics & Informatics
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• 제19권2호
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• pp.15.1-15.7
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• 2021

The direction of evolution can estimate based on the variation among nonsynonymous to synonymous substitution. The simulative study investigated the nucleotide sequence of closely related strains of respiratory syndrome viruses, codon-by-codon with maximum likelihood analysis, z selection, and the divergence time. The simulated results, dN/dS > 1 signify that an entire substitution model tends towards the hypothesis's positive evolution. The effect of transition/transversion proportion, Z-test of selection, and the evolution associated with these respiratory syndromes, are also analyzed. Z-test of selection for neutral and positive evolution indicates lower to positive values of dN-dS (0.012, 0.019) due to multiple substitutions in a short span. Modified Nei-Gojobori (P) statistical technique results also favor multiple substitutions with the transition/transversion rate from 1 to 7. The divergence time analysis also supports the result of dN/dS and imparts substantiating proof of evolution. Results conclude that a positive evolution model, higher dN-dS, and transition/transversion ratio significantly analyzes the evolution trend of severe acute respiratory syndrome coronavirus 2, severe acute respiratory syndrome coronavirus, and Middle East respiratory syndrome coronavirus.

• Journal of Photoscience
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• 제2권2호
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• pp.77-81
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• 1995

Photoreactions of pseudosaccharin ethers have been investigated. Pseudosaccharin 3-allyl ether undergoes a facile photoreaction via reaction pathways involving homolysis of bond between pseudosaccharyl oxygen and 3-allyl carbon, and excited nucleophilic substitution of allyloxy group by solvent which are not quenched by oxygen present in the reaction. Product yield demonstrates that the homolysis pathway predominates over the nucleophilic substitution in ca. 7:1 ratio. In contrast, pseudosaccharin alkyl ethers follow different reaction routes to produce two products, solvent-substituted pseudosaccharin alkyl ethers and reduction products, 3-alkoxy-1, 2-benzisothiazoles. The formations of reduction products, 3-alkoxy-1, 2-benzisothiazoles are completely quenched by oxygen.