• Bulletin of the Korean Chemical Society
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• 제8권5호
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• pp.424-425
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• 1987

Alkylation and allylation of arylborates give mono(ipso) and/or di(ortho and ipso) substitution products. Those factors which promote polarization or ionization of alkylating agents favor di substitution. The ${\sigma}$-type(ipso) substitution reaction of arylborates involves direct interaction of the carbon-boron bonds rather than predissociation of arylborates into aryllithiums and boranes.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 봄 학술발표회 논문집
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• pp.675-680
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• 2003

In this study, various tests are performed for the durability of the concrete using domestic recycled coarse aggregate including drying shrinkage, permeability, freezing-thawing resistance and $CO_2$ diffusivity. Tests of freezing-thawing resistance, chloride ion permeability and $CO_2$ diffusivity of recycled concrete show favorable results. But, the maximum drying shrinkage ratio to normal concrete is increased 24% with increasing substitution ratio of recycled aggregate. Therefore, for the use of recycled concrete in structures, the preventive measures of drying shrinkage is necessary in mix design and the adequate substitution ratio of recycled aggregate should be proposed.

• 한국구조물진단유지관리공학회 논문집
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• 제13권1호통권53호
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• pp.78-87
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• 2009

본 논문은 제강슬래그를 잔골재 대체재로 콘크리트에 활용할 경우 유리석회의 다량 함유로 인한 팽창성 때문에 콘크리트용 골재로서의 사용이 제한되고 있어 제강슬래그를 급냉시켜 유리석회의 함유량를 크게 낮춘 급냉제강슬래그를 잔골재로 활용한 콘크리트의 특성에 관한 연구이다. 따라서 급냉제강슬래그의 대체율 및 잔골재율을 달리하여 제작한 콘크리트 시험체의 슬럼프로스시험, XRD 및 SEM분석에 따른 수화특성, 재령에 따른 압축강도 시험, 길이변화시험 및 급속염소이온침투시험결 과를 비교 고찰하여 급냉제강슬래그의 적정 대체율 및 잔골재율을 도출하였다.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2009년도 추계 학술논문 발표대회
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• pp.127-131
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• 2009

The purpose of this study is to provide fundamental data on chloride diffusion from lightweight aggregate concrete by utilizing crushed stone-powder. Accordingly, the study performed experiments using concrete aggregates of Crushed Aggregate (CG), Single-sized Lightweight Aggregate (SLG), Continuous Graded Lightweight Aggregate (CLG), and using water-binder ratio of 0.4, 0.5, 0.6, and using binder of FA and BFS. The chloride diffusion coefficient is calculated after experiment based on NT BUILD 492. Diffusion coefficient of SLG and CLG were little bit higher than CG Concrete, but the difference is meaningless. Also, chloride diffusion coefficient indicates that it is highly affected by water-binder ratio, and it decreases with the decrease in water-binder ratio. The admixture substitution indicates decrease only with water-binder ratio of 0.4 for FA15% case, but admixture substitution indicates decrease with all levels of ratio for FA10 + BFS20% which means more appropriate. According to the analysis result of chloride diffusion from lightweight aggregate concrete, crushed stone-powder utilized lightweight aggregate concrete indicates higher chloride diffusion coefficient than CG concrete, which is not a significant difference, and can improve resistance through water-binder ratio and admixture substitution.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2006년도 춘계 학술발표회 논문집(II)
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• pp.161-164
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• 2006

The main objective of this study was to evaluated the physical properties of concrete with substitution ratio of recycled fine aggregate and recycled coarse aggregate made of waste concrete. The replacement ratios of recycled coarse and fine aggregate decided 0%, 30%, 40% and 50% respectively to get the deregulate of floor space Index. The test result showed that compression strength of cylinder mold decrease with the substitution ratio increase but its strength of replaced recycled fine aggregate higher than OPC.

• 생명과학회지
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• 제29권11호
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• pp.1235-1240
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• 2019

본 연구에서는 발효어분이 넙치의 증체율에 미친 조직학적 영향을 규명하기 위하여 수입어분에 대한 발효어분의 대체비율 0, 25, 50, 75 및 100%로 사육한 넙치로부터 간 및 근육을 적출하여 광학현미경을 이용한 미세구조적 분석을 실시하였다. 그 결과, 25% 대체군에서 간중량지수가 가장 높고 간 지방함유율이 가장 낮은 점으로부터 25% 대체군의 간의 우수한 건강성이 시사되었다. 또한 근섬유의 단면적도 25% 대체군이 가장 넓게 나타나, 운동성 또한 우수한 것으로 추측되었다. 즉 간 및 근육의 우수한 건강 상태가 높은 증체율을 나타내는데 영향을 미쳤음을 알 수 있었다. 한편, 증체율이 낮은 75% 및 100% 대체군에서는 간건강 및 근섬유의 발달이 좋지 못했는데, 이는 발효어분이 일정 비율 이상 포함될 경우 넙치의 건강에 좋지 않은 영향을 미칠 수 있음이 시사되었다.

• 펄프종이기술
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• 제35권1호
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• pp.41-47
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• 2003

Recently, interest in utilization plan of recycling paper have been enhanced. Therefore, this research aimed to develop the manufacture process of cellulose acetate using old newsprint by acetosolv pulping process. And the manufactured cellulose acetate was also analyzed, especially based on chemical properties. The summarized results in this research were as follows; Reaction time, kind and amount of catalyst, and ratio of liquor to material were varied during acetosolv pulping process of old newsprint. Ratio of liquor to material did not give the significant difference in reaction product. Delignification rate was increased with increasing reaction time during acetosolv pulping, but yield and degree of substitution decreased with increasing reaction time. Sulfuric acid are better catalyst than hydrochloric acid in acetosolv pulping process for old newsprint, and optimal addition amount of catalyst was 1% based on reaction material. Delignification, yield, and degree of substitution were influenced by the catalyst and reaction time. Under pulping condition of $120^{\circ}C$ in 1/12 liquor to material ratio and 60min, degree of substitution was about 0.7. The acetylation reaction was not completely caused by these reaction condition. The examination of the FT-IR spectra revealed that absorption band(1200$\textrm{cm}^{-2}$, 1,750$\textrm{cm}^{-1}$) caused by carbonyl group were confirmed.

• KIEAE Journal
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• 제8권3호
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• pp.69-76
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• 2008

This is an experimental study on the maximum load value and structural behavior of reinforced concrete columns containing shells as a substitute fine aggregate of concrete, through making reinforced concrete test columns with shells. In this study, the main factors consist of the grain sizes and the percentage of substitution of shells to fine aggregate in two kinds of water cement ratio. The results of the study showed as followed. The maximum load value decreased with increased the rate of substitution about shells and as the grain size of shells became smaller, the load values of them were somewhat changed higher but it is important that we must consider absorption rate of shells sufficiently. If we have a proper water cement ratio in column productions containing the shells, we can meet the requirement of the percentage of substitution until 30%. The deflection and deformation properties of reinforced concrete columns with shells represented typical curves like that of normal reinforced concrete. But as the failture types, they are able to make some change without being out of the fundamental graph forms. After the analyzing structural behaviors and the properties of reinforced concrete test columns containing shells, the most excellent grain size of shells represented 3.0mm and less with taking uniformly, and the percentage of practicable substitution of them to fine aggregate was about 30%.

• 한국산업융합학회 논문집
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• 제8권3호
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• pp.169-176
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• 2005

The purpose of this study is to develop the high strength crushed sand concrete in conditions of water binder ratios of 25, 30, 35% and blast-furnace slag substitutions of 0, 15, 30, 45%. Additionally, in case of water binder ratio of 30%, the maximum size of coarse aggregate is two kinds of 13, 19 mm. The conclusions of this study are as follows ; 1. The compressive strength appeared lower in early age as compared with that of plain concrete according to increasing of the blast-furnace slag substitution. But, the compressive strength was respectively 5, 6, 10% larger than that of plain concrete in case of 25, 30, 35% water binder ratios, 28 days, 30% blast-furnace slag substitution and 19mm coarse aggregate. 2. According to increasing of the blast-furnace slag substitution, the modulus of elasticity and the tensile strength of concrete increased. 3. The length change by the shrinkage increased when the larger coarse aggregate was used, and decreased according to higher blast-furnace slag substitution.

• Asian-Australasian Journal of Animal Sciences
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• 제31권6호
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• pp.851-858
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• 2018

Objective: This study was conducted to compare different methods on effective energy evaluation of corn silage for beef cattle. Methods: Twenty Wandong bulls (Chinese indigenous yellow cattle) with initial body weight of $281{\pm}15.6kg$, were assigned to 1 of 5 dietary treatments with 4 animals per treatment in a randomized complete block design. Five dietary treatments included group 1 with corn silage only diet, group 2 with corn silage-concentrate basal diet (BD) and 3 groups with 3 test diets, which were the BD partly substituted by corn silage at 10%, 30%, and 60%. The total collection digestion trial was conducted for 5 d for each block after a 10-d adaptation period, and then an open-circuit respiratory cage was used to measure the gas exchange of each animal in a consecutive 4-d period. Results: The direct method-derived metabolizable energy and net energy of corn silage were 8.86 and 5.15 MJ/kg dry matter (DM), expressed as net energy requirement for maintenance and gain were 5.28 and 2.90 MJ/kg DM, respectively; the corresponding regression method-derived estimates were 8.96, 5.34, 5.37, and 2.98 MJ/kg DM, respectively. The direct method-derived estimates were not different (p>0.05) from those obtained using the regression method. Using substitution method, the nutrient apparent digestibility and effective energy values of corn silage varied with the increased corn silage substitution ratio (p<0.05). In addition, the corn silage estimates at the substitution ratio of 30% were similar to those estimated by direct and regression methods. Conclusion: In determining the energy value of corn silage using substitution method, there was a discrepancy between different substitution ratios, and the substitution ratio of 30% was more appropriate than 10% or 60% in the current study. The regression method based on multiple point substitution was more appropriate than single point substitution on energy evaluation of feedstuffs for beef cattle.