• 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%.

• KIEAE Journal
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• 제7권5호
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• pp.135-142
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• 2007

This is an experimental study on the structural characteristics of reinforced concrete beams using of the oyster shells as a substitute fine aggregate of concrete. In this study, the main factors consist of the grain sizes and the percentage of substitution of oyster shells to fine aggregate in the equal water cement ratio. The results of the study showed as followed. The initial load value of them represented similar constant within 10% of the maximum load value in each test beam. But the maximum load value and the ultimate load value decreased with increased grain size and the rate of substitution. As the grain size of oyster shells became smaller, the load values of them were somewhat higher. The deflection among deformation properties of reinforced concrete beams with oyster shells represented typical curves like that of normal reinforced concrete. In the deformation of steel and concrete, the deformation was proportionated to the load till yield point and from yield point until approaching the ultimate load point. One type was typical curve of the load and the deformation and the other type irregularly was changed to very small deformation for the load increase centering around load axis. After the analyzing structural behaviors and the properties of reinforced concrete test beams with oyster shells, the most excellent grain size of oyster shells represented 1.0mm and less or 5.0mm and less with taking uniformly, and the percentage of practicable substitution of them to fine aggregate was about 30%.

• Asian-Australasian Journal of Animal Sciences
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• 제18권2호
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• pp.209-213
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• 2005

This study was conducted to determine the optimum substitution level of dried leftover food (DLF) in formula feed for Hanwoo (Korean Native Cattle) steers. A total of forty growing steers were assigned to 5 treatments based on substitution level of DLF (at 0, 25, 50, 75 and 100% level of formula feed). The experiment was carried out with growing steers from 6 months of age to 24 months of age. Average daily gain (ADG) was not affected by DLF substitution level up to 75% of formula feed. However ADG decreased at 100% substitution level. Daily feed intakes were similar among treatments but the amount of feed per 1 kg gain increased with increasing substitution level of DLF. Dressing percentage was around 62% in all treatments without any significant differences. Proportion of quality beef higher than grade 1 was the greatest from animals fed 25% substitution level of DLF. Economic efficiency for Hanwoo steer operator was the highest with 50% substitution level of DLF.

• Asian-Australasian Journal of Animal Sciences
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• 제20권1호
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• pp.45-51
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• 2007

A growth trial (Expt. 1) and an in vitro fermentation experiment (Expt. 2) were conducted to determine the response of growth performance, cecal fermentation characteristics and in vitro gas production to incremental levels of substitution of digestible fiber for lignified fiber in the diet of weaned rabbits. Three diets, formulated by substituting soyhulls (SH; used as digestible fiber source) for soybean straw (used as lignified fiber source) at substitution levels of 0, 25 and 50%, were used in a factorial design. In the growth trial (Expt. 1), increasing levels of SH substitution resulted in a quadratic increase in daily body weight gain rate (p<0.04) and feed conversion efficiency (p<0.02), but in a numerical decrease in dietary DM intake (p=0.15). When SH were included in the diet at 25% substitution level, rabbits had the highest rate of liveweight gain and feed conversion efficiency. As SH substitution level increased, pH values and ammonia-N of cecal contents linearly (p<0.001) decreased, but total VFA concentration linearly (p<0.03) increased. With incremental levels of SH substitution, the percentage of acetate and butyrate linearly (p<0.05) reduced, but the percentage of propionate and minor acids linearly (p<0.03) increased. Increasing the SH substitution levels tended to increase incidence of diarrhea. In the in vitro fermentation experiment (Expt. 2), regardless of origin of substrates fermented, increasing SH substitution level resulted in increased maximal gas production (p<0.001) and shortened gas production lag time, but had no effect on gas production rate (p>0.2). These observations suggest that incrementally feeding SH to rabbits could stimulate their cecal microbial activity, allowing cecal fermentation to shift towards favoring fiber digestion. In conclusion, digestible fiber from soyhulls may partially substitute for more lignified fiber, soybean straw, without having an adverse effect on cecal fermentative and microbial activity and growth performance. For growing rabbits, about 73% of total dietary NDF should be supplied by effective NDF, the remainder could come from digestible NDF, such as soyhulls.

• 아동학회지
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• 제29권6호
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• pp.147-161
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• 2008

The present study compared characteristics of Korean nominal particles (occurrence, error, error patterns) of ten 5- to 6-year-old Korean-English simultaneous bilingual children with ten Korean monolingual children. Data were analyzed by Mann-Whitney U test and Spearman Rank Correlation and by qualitative analysis. Results were (1) bilingual children showed significantly lower frequency based on the number of occurrence of nominal particles per utterance. (2) The error percentage of adverbial markers was significantly higher for bilingual children. (3) Error patterns of bilingual children showed a higher percentage of in-case substitution and double use error. These findings suggest that Korean-English simultaneous bilingual children have a different Korean nominal particles development from Korean monolingual children.

• 한국구조물진단유지관리공학회 논문집
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• 제10권5호
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• pp.137-147
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• 2006

본 연구는 남해안 연안에 방치되고 있는 굴패각을 세골재 크기의 5.0mm이하로 분쇄하여 실제 현장에서 사용가능한 세골재 대체재로 활용하여 굴패각을 사용한 콘크리트의 성질 및 제반 강도들에 대해 연구한 것이다. 이를 위해 기본 실험과 주요 변화 요인들에 대해 1,028개의 공시체 및 시험체를 제작 실험한 결과 굴패각을 사용한 콘크리트 제반 강도는 일반콘크리트 강도와 최대 10%정도 차이를 보였으며 세골재 대체재로서 우수한 굴패각 입도크기는 5.0mm이하를 균등하게 취한 경우로 약 30%까지는 대체 가능한 것으로 나타났다. 그리고 본 논문에서는 굴패각을 사용한 제반 콘크리트 강도상호 관계식들을 제시하였고 이의 탄성계수는 굴패각 대체율이 증가할수록 감소하였는데 대체율 10%까지는 거의 유사한 값을 보였다.

• Bulletin of the Korean Chemical Society
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• 제18권8호
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• pp.868-873
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• 1997

Nucleophilic substitution reactions of 1-phenylethyl chlorides (1-PEC; YC6H4CH(CH3)Cl) with phenoxides (XC6H4O-) and thiophenoxides (XC6H4S-) are investigated theoretically using the PM3 method. The Bronsted α and β values are greater for the phenoxides indicating a more advanced reaction in the transition state (TS) than for the thiophenoxides. This is supported by a greater magnitude of ρX (- 6.4 ∼ - 7.4) and ρXY (- 0.76) for the phenoxides than for the thiophenoxides (ρX = - 3.6 ∼ - 4.4 and ρXY = - 0.60). The percentage bond order changes, %Δn≠, suggest that the extents of bond making and breaking are similar for the phenoxides and hence the TS is symmetrical, but bond making is somewhat greater than bond cleavage for the thiophenoxides indicating an unsymmetrical TS. The reactions in the gas phase for both nucleophile series proceed by a SN2 mechanism with a tight TS and negative charge development on the reaction center carbon, Cα. The reactions in water investigated with model systems of benzyl and 1-phenylethyl chlorides using the Cramer-Truhlar solvation model (PM3-SM3) indicate that the reactions of 1-PEC are far more complex due to enhanced stabilization of the carbocation by the methyl substitution for a benzylic hydrogen.

• 한국인쇄학회지
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• 제12권1호
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• pp.81.1-91
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• 1994

Irradiation of aromatic diazonium salts resulted in an effcient elimination of nitrogen, yielding substitution products. This paper was not only studies about photolysis of aromatic diazonium with double salts but also coexistence of ion and radical when they was photolysis. Photolysis of aromatic diazonium was depend on excite wave length therefore photolysis products out put different absorption intensity such other. We also confirmed coexistence of ion and radical when they was accomplished photolysis. In case of BD, there are ion decomposition process about 90 percentage, decreased ion decomposition process the other side radical`s it was becomeing increased according to excite of short-wave length.

• Asian-Australasian Journal of Animal Sciences
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• 제27권1호
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• pp.24-29
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• 2014

The objective of this study was to assess the effect of substituting corn with soybean hulls on the ingestive behavior and nitrogen balance of Santa Ines lambs. A total of 25 lambs with an initial body weight of $20{\pm}2$ kg at approximately six months of age, sheltered individually in stalls ($1.10m{\times}1.0m$), considering an entirely casual experimental delineation. Soybean hulls were substituted for corn at 0, 250, 500, 750, and 1,000 g/kg of dry matter (DM). The time spent feeding, ruminating, masticating, and resting was not affected by the substitution of corn with soybean hulls. In fact, the feeding efficiency in g DM/h and the rumination efficiency in g DM/bolus increased linearly with soybean hull substitution in the feed. Although the nitrogen balance was not altered by the use of soybean hulls as a substitute for corn in the diets of Santa Ines lambs, the N ingested and N digested expressed in g/d, N retained as a percentage of that ingested, and N retained as a percentage of that digested displayed quadratic behavior. In conclusion, corn can be substituted with soybean hulls up to 1,000 g/kg of dry matter in the concentrate, without changing the ingestive behavior and nitrogen balance.

• 한국축산식품학회지
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• 제26권1호
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• pp.121-126
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• 2006

Major milk proteins have considerable variane which comes from substitution and deletions in their amino arid sequences. Variants in genes that code for milk proteins, such as ${\beta}$-lactoglobulin (${\beta}-LG$) have been established as genetic markers for milk production and milk protein composition in dairy cattle. The effect of ${\beta}-LG$ variant on milk production traits, such as milk yield. fat yield, protein yield, fat percentage and protein percentage, was estimated for 482 Holstein cows in the first lactation. The ${\beta}-LG$ variants were determined by PCR-RFLP technique at the DNA level. Single trait linear model was used for the statistical analysis of the data. Results of this study indicated that ${\beta}-LG$ variants affected significantly protein yield (p<0.05) and fat percentage (p<0.05). Animals with the AA variant produced 31kg of milk protein more than animals with the BB variant. On the contrary, cows with the BB variant had fat percentage higher by 0.35 and 0.32% compared with cows with the AA and AB variants, respectively. No associations between the ${\beta}-LG$ variants and milk yield, protein percentage and fat yield were found Therefore, milk production traits could be improved through ${\beta}-LG$ typing by increasing the frequency of A variant for protein yield or the frequency of B variant for fat content in Holstein dairy cattle population.