• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 봄 학술발표회 논문집
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• pp.263-268
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• 2000

Recently, the recycling of the by-products was attempted to various fields. One of the major industry, the copper manufacturing industry produced a lot slags. in this study, the copper smelting slag was used to use practically application for the aggregate of concrete. To find the optimum mixing ratio of mortar with the copper smelting slag as substitution for sand, the mixing ratio was increased 1:2 to 1:5 step by step and every mixture was contained 5 steps sand substitutive ratio. The substitutive ratio of sand was increased 25% st대 by step from 0% to 100%. The result of this study was shown as follows. 1. In the every mixture, as the substitutive ratio was increased, the flow was decrease 3.64% from 18cm, and the unit content weigth was increased 5.5% in average. 2. The property of the strength was judged that it was more affected W/C and mixing ratio than the copper smelting slag.

• 한국분무공학회지
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• 제24권4호
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• pp.194-202
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• 2019

A mixture preparation strategy was proposed and evaluated in a diesel-natural gas dual-fuel engine to reduce hydrocarbon (HC) and carbon monoxide (CO) emissions under low load conditions. An experimental investigation was conducted in a single-cylinder compression-ignition engine. Natural gas was supplied with air during the intake stroke, and diesel was injected directly into the combustion chamber during the compression stroke. First, effects of diesel start of energizing (SOE) and natural gas substitution ratio on the combustion and exhaust gas emissions were analyzed. Based on the results, the mixture preparation strategy was established. A low natural gas substitution ratio and a high exhaust gas recirculation (EGR) rate were effective in reducing the HC and CO emissions.

• 청정기술
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• 제8권3호
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• pp.129-139
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• 2002

This is the study for recycling waste foundry sand. Authors studied about main subject of grading of aggregate and three experimental items such as physical properties of waste foundry sand, optimum grading for concrete products of low water ratio, and quality variations of concrete products according to substitution proportion of fine aggregate as waste foundry sand. We were convinced of following results by experimental study. The first was that waste foundry sand was not fit as the aggregate for concrete because of bad qualities such as grading, unit weight, solid volume and passing 0.08 mm seive, so it is proper to composition using with other fine aggregetes. The second was that optimum grading is fineness modulus of 2.77 to 3.28 And the last is that optimum condition about substitution proportion as waste foundry sand is 10% fine aggregate.

• 동아시아식생활학회지
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• 제26권5호
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• pp.407-417
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• 2016

Effects of resistant starch as a functional substitute on the quality of Yukwa were determined. Replacement ratios of resistant starch were 2, 4, and 6% of glutinous rice flour. Regarding pasting properties of Yukwa dough replaced with resistant starch, initial pasting temperature significantly increased and peak viscosity significantly decreased with increasing resistant starch. The moisture contents of bandegi and Yukwa base replaced with resistant starch were higher than that of the control. The expansion ratio of Yukwa base replaced with resistant starch significantly decreased with increasing resistant starch, and there were no significant differences in the oil absorption ratio. Lightness (L) of Yukwa base replaced with resistant starch increased significantly with increasing resistant starch. Appearance of Yukwa base replaced with resistant starch showed a shortened length and increased width with increasing resistant starch, and cross-section showed an oval shape, fine air cell distribution, and increased outer layer thickness. Hardness and peak number increased significantly with increasing resistant starch. The overall acceptability of Yukwa base replaced with 6% resistant starch was the highest among the samples, but the result was not significant. The above results show that resistant starch substitution in Yukwa improved the texture and further could improve health functionality due to its dietary fiber content. Resistant starch was appropriate as a 6% replacement for glutinous rice flour in Yukwa.

• 한국동물학회지
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• 제35권1호
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• pp.80-86
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• 1992

The nucleotide sequences of 185 rRNAs of the five Korean decapods were partially determined by the direct sequencing method using the reverse transcriptase. ne average GC content of five species was 51.1% which is higher than that of yeast(45.0%) and lower than those of frog (53.0%) and rat (55.6%). This result follows the general patterns of the GC content in the nucleotides of the nucleic acid shown among the various phylogenetic groups. The average ratio of transrional/transversional nucleotide substitution of pairwise comparison among six species (including Anemia salina) was 1.200 $\pm$ 0.310 when whole region alas examined. However, the ratio showed some differences when the conservative regions and variable regions frere separatelv examined. The molecular phylogenies of the five species were constructed by using two different tree making methods. In general the results support the previously reported molecular phylogeny of the decapod crustaceans. However, our results indicate thats in the analysis of the sequence dat3, the UPGMA clustering method of the distance matrix method should be carefully employed after considering the rate of nucneotide substitution in the different regions of the molecule.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2009년도 춘계 학술논문 발표대회 학계
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• pp.113-117
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• 2009

Fly ash (called FA hereafter) that results from thermal power plants is a long-term strength improving substance with reactivity to pozzolan and has been used for long. However, large amount of FA shows many advantages such as reduction of hydratio energy, long-term improvement in strength and economic feasibility and also has difficulties from reduction in initial strength and durability. In a preceding study, fine particle cement was applied to test the effects on initial strength. Therefore in this study, the effects of fine particle cement on the quality of FA concrete were reviewed. The results can be summarized as follows. Liquidity was increased by the most at FC substitution ratio of 15%. Air capacity was reduced according to increasing substitution ratio of FA and FC. Compressive strength showed high strength expression at all ages when FC was substituted at 45%. Synthesizing the above results, appropriate mixing of FC in FA concrete can improve liquidity, reduce unit quantity and show improvement in strength. In particular, mixed use of FC seems effective in improving early quality of concrete.

• 디지털융복합연구
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• 제14권10호
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• pp.375-380
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• 2016

본 연구에서는 폭주근점 변화를 통해 양안시 기능 평가의 가능성을 확인하고자 하였다. 연구대상자는 사위를 제외한 안질환이 없고 단안교정 소수 시력 1.0 이상인 30명(정시 16명, 근시 14명)이었다. 조절근점과 폭주근점, 사위검사는 평상시와 +1D의 자극 시에 측정하였다. 대상자의 폭주근점은 +1D의 자극 시 폭주근점보다 1.77cm 작게 나타났고, 근시보다 정시에서 폭주근점이 작게 나타났다. 정시 대상자에서 폭주근점과 +1D의 자극 시 폭주근점의 차이는 증가하였다. 폭주근점이 커질수록 근거리 외사위에 가까워졌으며, AC/A비는 크게 나타났다. 연구결과는 폭주근점 변화가 양안시의 참조변수인 AC/A비를 대체할 수 있는 것을 보여주었다. 다른 양안시 기능 평가 검사들과 융합하고 비교분석한다면, NPC 변화는 대체 평가지표로써 개발될 수 있을 것이다.

• 한국재난정보학회 논문집
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• 제9권4호
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• pp.469-475
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• 2013

이 연구의 목적은 고로슬래그 미분말을 혼입한 순환골재 콘크리트의 압축강도 및 동결융해 저항성을 평가하는 것이다. 이를 위하여 순환골재 대체율에 따라 고로슬래그 미분말 혼입률을 변수로 콘크리트 공시체를 제작한 후 이들의 압축강도 및 동결융해 저항성을 평가하였다. 고로슬래그 미분말 20% 혼입한 순환골재 콘크리트의 재령 28일 압축강도는 플레인 콘크리트보다 훨씬 우수하였고, 동결융해 300 사이클 시험 결과, 콘크리트의 공기량을 4~6% 유지하였을 때, 순환골재 대체율 및 고로슬래그 미분말 혼입률이 동결융해 저항성에 미치는 영향은 거의 없는 것으로 나타났다.

• 한국건축시공학회지
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• 제12권5호
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• pp.468-477
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• 2012

This study aimed to mix and test mortar incorporating activated Hwangtoh to improve the Hwangtoh brick bond strength of brick structures. To do this, the bond strength correlation of mortar was analyzed by means of materials and experiment factors and levels, and the optimum conditions were suggested after analyzing the physical properties of brick and the mix ratio of mortar and additive. Furthermore, the compressive strength and bond strength were found to be in inverse proportion, and in terms of the materials and mixing level, W/C ratio, substitution ratio of activated Hwangtoh, and fine aggregate grading were shown to have a considerable influence on the strength. In conclusion, the optimum mixing conditions to improve the bond strength are found to set W/C ratio at 65% and replacmenet ratio of activated Hwangtoh at 10%.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2012년도 추계 학술논문 발표대회
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• pp.103-105
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• 2012

With blast-furnace slag is a by-product generated when pig iron is produced. It has been used as the concrete admixture due to high reactivity. However, It causes low strength development during early age. In order to make up for this drawback, in this study, we evaluated compressive strength of mortar replaced with high volume blast-furnace slag. Experimental results, Compressive strength of mortar based on blast-furnace slag is affected by cement type, substitution rate of blast-furnace slag and pH after mixing.