• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 추계 학술발표회
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• pp.1559-1570
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• 2008

A new grouting material named 3S is developed that can be used effectively for reinforcing cut surface of weathered rock in processing of tunneling. The new material is composed of mostly micro slag cement and general Portland cement, but the material is foundered again upto $8,000\;cm^2/g$ of specific area so that it can be easily infiltrated in to the ground. For verifying technical and engineering quality of the material several laboratory tests with specially designed test apparatus were performed including compression tests, infiltration tests and resonant column tests. It was verified that the newly developed grouting material at early age of 1 or 3 days generates 200~1500% higher compressive strength and 400~560% larger elastic modulus than those of the LW(LW-1) or micro-cement(LW-2) grouting materials in the market. In addition, the new 3S grouting material could be so easily infiltrated into the model ground in the lab tests that it produces 4 times larger grouted roots in average compared to the usual water glass type grouting material(LW-1). Thus, it can be said that the newly developed grouting material can effectively prevent inflow water into tunnel compared to LW grouting materials.

• Journal of Animal Science and Technology
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• 제57권9호
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• pp.35.1-35.8
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• 2015

Background: An experiment was conducted in Vietnam to test the hypothesis that total dry matter (DM) intake and liveweight (LW) gain would increase in a curvilinear manner with increasing amounts of concentrate offered. Method: There were five treatments: a basal diet of Guinea grass fed at 1 % of LW and rice straw fed ad libitum (T0), or this diet supplemented with concentrate at 0.6 (T1), 1.2 (T2), 1.8 (T3), or 2.4 % of LW (T4). The concentrate comprised locally available ingredients, namely cassava chips, rice bran, crushed rice grain, fishmeal, salt, and urea, mixed manually. Results: Concentrate intake increased from T0 to T3, but there was no difference in concentrate intake between T3 and T4. Total feed intake increased in a curvilinear manner from 4.0 to 6.4 kg DM/d as the quantity of concentrate consumed increased. The substitution of concentrate for grass and rice straw increased with increasing consumption of concentrate and was as high as 0.49 kg DM reduction per kg of concentrate consumed. LW gain increased curvilinearly, with significant differences between T0 (0.092 kg/d), T1 (0.58 kg/d) and T2 (0.79 kg/d); but there were no significant differences in LW gain between T2, T3 (0.83 kg/d) and T4 (0.94 kg/d).With increasing amount of concentrate in the diet, the digestibilities of dry matter, organic matter, crude protein, and crude fat increased, but NDF digestibility decreased. Conclusion: Based on these results, young Vietnamese Brahman-cross growing cattle will respond to a locally-sourced concentrate mix offered at a level of up to 1.2 % of LW.

• Asian-Australasian Journal of Animal Sciences
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• 제21권12호
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• pp.1736-1744
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• 2008

Two experiments were conducted in central Vietnam to test the hypothesis that supplementation with a concentrate, comprising rice bran (45% fresh basis), maize (49%), fish meal (3%), urea (2%) and salt (1%), up to 2% of live weight (LW)/d (dry matter (DM) basis) would linearly increase digestible organic matter intake and LW gain of yellow cattle. In both experiments, there were five treatments, namely a basal diet of fresh grass fed at 1.25% of LW (experiment 1, elephant grass, Pennisetum purpureum; experiment 2, native grass) and rice straw (Oryza sativa) fed ad libitum or this diet supplemented with concentrate at about 0.3, 0.7, 1.3 or 2.0% LW. There were 4 male growing cattle per treatment in experiment 1 and 3 in experiment 2. Diets were fed for 44 (experiment 1) or 49 (experiment 2) days, with feed intake recorded daily, LW measured about weekly and digestibility measurements made over 7 days commencing on day 24 (experiment 1) or day 10 (experiment 2). The elephant grass and native grass had neutral detergent fibre (NDF) concentrations of 82 and 73% DM, and nitrogen concentrations of 1.3 and 1.8% DM, respectively. The rice straw used had a NDF concentration of 79-84% DM and nitrogen concentration of 0.8% DM. The concentrate had NDF and nitrogen concentrations of 33 and 2.8% DM. In both experiments, DM intake increased (p<0.001) linearly as the amount of concentrate consumed increased. Rice straw intake declined (p<0.001) (experiment 1: 1.24 to 0.48 kg DM/d; experiment 2: 0.95 to 0.50 kg DM/d) as concentrate intake increased. Grass intake was not significantly affected by concentrate intake in either experiment. The lowest amount of concentrate supplement increased forage intake, after which substitution rate increased as the amount of concentrate consumed increased. However, substitution rates at the highest amount of concentrate consumed were modest at 0.3 to 0.5 kg DM reduction in forage intake/kg DM supplement consumed. In both experiments, digestible organic matter intake increased linearly (p<0.001) (experiment 1: 1.16 to 2.38 kg/d; experiment 2: 1.30 to 2.49 kg/d) as the amount of supplement consumed increased, as did LW gain (experiment 1: 0.15 to 0.81 kg/d; experiment 2: 0.15 to 0.77 kg/d). This was associated with significant (p<0.01) linear increases in organic matter intake and apparent organic matter digestibility. Neutral detergent fibre digestibility declined as concentrate intake increased, but the effect was not significant (p = 0.051) in experiment 2. These results are discussed in relation to existing literature and potential to improve the profitability of cattle fattening in central Vietnam.

• Asian-Australasian Journal of Animal Sciences
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• 제24권6호
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• pp.744-751
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• 2011

Meat production and quality traits in beef cattle are largely affected by genetic factors. Acetyl-Coenzyme A carboxylase-${\alpha}$ (ACACA) plays a key role in the regulation and metabolism of fatty acid biosynthesis in mammalian animals. The gene encoding ACACA enzyme was chosen as a candidate gene for carcass and meat traits. In this study, we investigated effects of single nucleotide polymorphisms (SNPs) in the ACACA gene on beef carcass and meat traits in Hanwoo (Korean cattle) populations. We have sequenced a fragment of intron I region of the Hanwoo ACACA gene and identified two SNPs. Genotyping of the two SNP markers (g.2344T>C and g.2447C>A) was carried out using PCR-SSCP analysis in 309 Hanwoo steers to evaluate their association with carcass and meat production traits. The g.2344C SNP marker showed a significant increasing effect on LW (p = 0.009) and CW (p = 0.017). Animals with the CC genotype had higher CW and LW compared with TT and TC genotypes (p<0.05). The g.2447A SNP marker was associated with higher MC (p = 0.019). Animals with the AA genotype had higher MC than animals with CC and CA genotypes (p<0.05). Although the degree of linkage disequilibrium (LD) was not strong between g.2344T>C and g.2447C>A in the LD analysis, four major haplotype classes were formed with two SNP information within the ACACA gene. We constructed haplotypes using the HaploView software package program and analyzed association between haplotypes and carcass traits. The haplotype of ACACA gene significantly affected the LW (p = 0.027), CW (p = 0.041) and MC (p = 0.036). The effect of h1 haplotype on LW and CW was larger than that of h3 haplotype. Animals with the h1 haplotype also had greater MC than did animals with h2 haplotype. Consequently, the ACACA gene could be useful as a DNA marker for meat production traits such as carcass yield and meat contents in Hanwoo.

• 한국산림과학회지
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• 제70권1호
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• pp.103-108
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• 1985

지리산(智異山) 국립공원내(國立公園內)의 천연혼효림(天然混淆林)을 구성(構成)하고 있는 주요(主要) 13개(個) 활엽수종(闊葉樹種)을 대상(對象)으로, 잎의 기하학적(幾何學的) 형태(形態)에 따른 엽면적(葉面積)(A), 엽장(葉長)(L), 엽폭(葉幅)(W)간(間)의 통계적(統計的) 상호관계(相互關係)를 규명(糾明)함으로써 신뢰(信賴)할 수 있는 엽면적(葉面積) 추정식(推定式)을 찾고자 하였다. 정확(正確)한 추정(推定)이 특별(特別)히 요구(要求)되지 않을 때는 A=bLW을 이용하는 것이 일반적(一般的)이다. 이 식(式)에서 계수(係數)b의 값은 수종(樹種)에 따라 고유(固有)한 값을 나타내었으나 전체적(全體的)으로는 0.579~0.717의 범위내(範圍內)에 분포(分布)하였다. 그러므로 지리산(智異山) 천연림(天然林)의 경우(境遇) 임분(林分) 전체(全體)의 직략적(職略的)인 엽면적(葉面積) 추정시(推定時)에는 A=2/3LW의 추정식(推定式)을 사용(使用)하여도 무방(無防)할 것으로 사료(思料)된다. 좀 더 정확(正確)한 추정(推定)을 요(要)할 시(時)에는 회귀방정식(回歸方程式)을 이용(利用)한다. 본(本) 연구(硏究)에서는 9가지 형태(形態)의 식(式)에 적용(適用)하여 결정계수(決定係數)($R^2$)를 기준(基準)으로 엽면적(葉面積) 추정식(推定式)에 가장 적합(適合)한 식(式)의 형태(形態)를 찾아 보았다. 그 결과 단엽(單葉)을 가진 활엽수(闊葉樹)에서는 이제까지 많이 사용(使用)하지 않았던 ${\log}A=b_0+{\log}LW$가 8가지 수종(樹種)에서 가장 적합(適合)한 형태(形態)로 나타났다. 이 식(式)의 계산은 조금 복잡(複雜)하나 컴퓨터를 이용(利用)하면 정확(正確)하고 실용적(實用的)인 추정식(推定式)이 될 수 있다. 그 밖에 $A=b_0+b_1LW$ 및 $A=b_0+b_1L^2+b_2W^2$도 좋은 형태(形態)로 나타났다. 이 두 가지를 비교(比較)해 볼 때 결정계수(決定係數)는 비슷하나 F값은 전자(前者)가 월등히 큰 값을 보임으로써 이를 사용(使用)하는 것이 더 간편(簡便)하며 신뢰도(信賴度)가 높을 것으로 사료(思料)된다.

• 수산해양기술연구
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• 제50권4호
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• pp.447-454
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• 2014

The marine microalgae Chaetoceros calcitrans was cultured under a fluorescent lamp (CON) and light-emitting diodes (LEDs) of various wavelengths (blue, LB; red, LR; green, LG; white, LW); changes in growth, fucoxanthin, chlorophyll-a, amino acid and fatty acid profiles were investigated. LR-exposed cultures exhibited the highest specific growth rate (SGR) (0.34), whereas LG-exposed cultures showed the lowest SGR (0.26). After cultivation for 10 days, the maximum dry cell weight (g/L) of LR-exposed cultures was significantly higher than that of those exposed to other light conditions (LR${\geq_-}$CON>LB${\geq_-}$LW${\geq_-}$LG). Eicosapentaenoic acid (EPA) levels were significantly higher in CON-exposed cultures compared to those exposed to LW (P<0.05), with no marked difference compared to those exposed to LB, LR and LG (P>0.05). The fucoxanthin content was highest in LB-exposed cultures ($6.3{\mu}g/mL$), whereas LW showed the lowest ($3.6{\mu}g/mL$; P<0.05). Chlorophyll-a content was highest in cultures exposed to LB compared to other light sources. These results suggest consistent differences in growth and biochemical composition after exposure to light of different wavelengths.

• 한국수산과학회지
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• 제46권3호
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• pp.259-265
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• 2013

The marine microalgae Nannochloropsis sp. was cultured under a metal halide lamp (MH) or light-emitting diodes (LEDs) of various wavelengths (blue, LB; red, LR; yellow, LY; green, LG; white, LW); changes in growth, total carotenoid, chlorophyll a, amino acid and fatty acid profiles were investigated. LB-exposed cultures exhibited the highest specific growth rate (SGR) (0.32), whereas LY-exposed cultures showed the lowest SGR (0.18). After cultivation for 9 days, the maximum dry cell weight (g/L) of LB-exposed cultures was significantly higher than that of those exposed to other light conditions (LB>MH>LW$${\geq_-}LG{\geq_-}$$LR>LY). The essential amino acid (EAA, %) contents of cultures exposed to LG, LB, LR and MH were higher than those exposed to LY and LW (P<0.05). Eicosapentaenoic acid and n-3 highly unsaturated fatty acid levels were significantly higher in MH-exposed cultures compared to those exposed to LY (P<0.05), with no marked difference compared to those exposed to LB, LG, LR and LW (P>0.05). The total carotenoid content was highest in LR-exposed cultures (18.0 mg/L), whereas MH showed the lowest (11.8 mg/L; P<0.05). Chlorophyll a content was highest in cultures exposed to LR compared to other light sources. These results suggest consistent differences in growth and biochemical composition after exposure to light of different wavelengths.

• 자원리싸이클링
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• 제17권1호
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• pp.20-28
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• 2008

신평장림 공단에서 배출되는 피혁폐기물은 46.3%의 탄소를 함유하고 있으며 열중량분석에 의하면 $500^{\circ}C$에서 중량손실이 약 50%이었다. $K_2CO_3$을 이용한 화학적 활성화법으로 $800^{\circ}C$에서 약 30분간 질소분위기 중에서 피혁폐기물을 원료로 한 피혁폐기물 활성탄[leather waste chemically activated carbon, LW4AC]을 제조하였다. 피혁폐기물 활성탄의 요오드 값, 메틸렌블루 탈색력은 각각 968 mg/g, 158 mL/g이었다. $K_2CO_3$와 피혁폐기물 혼합비 $[K_2CO_3/LW]$가 증가할수록 세공부피가 발달함을 알 수 있었다.

• Restorative Dentistry and Endodontics
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• 제44권1호
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• pp.6.1-6.11
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• 2019

Objectives: The aim of the present study was to evaluate the effect of whitening mouth rinses alone and in combination with conventional whitening treatments on color, microhardness, and surface roughness changes in enamel specimens. Materials and Methods: A total of 108 enamel specimens were collected from human third molars and divided into 9 groups (n = 12): 38% hydrogen peroxide (HP), 10% carbamide peroxide (CP), 38% HP + Listerine Whitening (LW), 10% CP + LW, 38% HP + Colgate Plax Whitening (CPW), 10% CP + CPW, LW, CPW, and the control group (CG). The initial color of the specimens was measured, followed by microhardness and roughness tests. Next, the samples were bleached, and their color, microhardness, and roughness were assessed. Data were analyzed through 2-way analysis of variance (ANOVA; microhardness and roughness) and 1-way ANOVA (color change), followed by the Tukey post hoc test. The Dunnett test was used to compare the roughness and microhardness data of the CG to those of the treated groups. Results: Statistically significant color change was observed in all groups compared to the CG. All groups, except the LW group, showed statistically significant decreases in microhardness. Roughness showed a statistically significant increase after the treatments, except for the 38% HP group. Conclusions: Whitening mouth rinses led to a whitening effect when they were used after conventional treatments; however, this process caused major changes on the surface of the enamel specimens.

• 한국지반환경공학회 논문집
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• 제17권9호
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• pp.37-45
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• 2016

본 연구는 기존 차수 그라우팅공법에서 사용되는 규산질 물유리계(규산소다) 재료에 대해 환경성과 주입재 내구성 문제에 대한 문제점을 인식하여 이를 대체한 실리카졸(Silica-Sol)의 성능효과와 실리카졸을 사용한 공법의 현장 적용성을 분석함으로써 타공법 대비 효과를 비교 제시하였다. 환경성 내구성 평가와 관련 실내에서 주입재에 대한 어독성, 수중불분리 및 pH 농도 변화, 용출, 압축강도, 길이변화(수축량), 해수영향에 의한 약액 효능 분석 시험을 한 결과 실리카졸 공법은 물유리계인 LW 공법에 비해 압축강도는 약 1.3배 강하고 수축률은 3~8배 정도 적었으며, 토양오염에 영향을 줄 수 있는 유해성분(Cd, Cu, Hg, $Cr^{+6}$, 유기인)이 전혀 없는 것으로 나타났다. 특히 어독성의 경우 수조 내 물의 pH 농도 변화가 거의 없이 공시어 또한 모두 장시간 생존하는 것을 확인할 수 있었다. 또한, 해수 염분에 의한 약액의 강도, 내구성 저하가 없는 것으로 분석되었다. 현장시험에서는 주입실시공 후 표준관입시험, 공내재하(LLT), 전단시험(BST)을 통해 지반개량에 대한 강도 물성치 증가 및 현장투수시험을 통해 풍화토(토사)층의 투수계수가 $1{\times}10^{-5{\sim}-6}cm/sec$로 저하됨으로써 현장적용에 대한 공법 시공 효과를 관찰할 수 있었다.