• 한국건축시공학회지
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• 제8권1호
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• pp.57-62
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• 2008

Twelve mortars were mixed and tested to explore the effect of gypsum on the compressive strength development and shrinkage strain of alkali-activated mortars. Powder typed sodium silicate and ground granulated blast-furnace slag were employed as alkaline activator and source material, respectively, to produce cementless mortar. The main variables investigated were alkali quality coefficient combining the concentration of activator and main compositions in source material, and the adding amount of gypsum ranged between 1 and 5% with respect to the weight of binder. Initial flow, compressive strength development, modulus of rupture, and shrinkage strain behavior of mortar specimens were measured. In addition, the hydration production of alkali-activated pastes with gypsum was traced using X-ray diffraction and energy-dispersive X-ray analysis combined with scanning electron microscope image. Test results showed that the initial flow of slag-based alkali-activated mortar was little influenced by the adding amount of gypsum. On the other hand, the effect of gypsum on the compressive strength of mortar specimens was dependent on the alkali quality coefficient, indicating that the compressive strength increased with the increase of the adding amount of gypsum until a certain limit, beyond which the strength decreased slowly. Shrinkage strain of mortar tested was little influenced by the adding amount of gypsum because no ettringite as hydration product was generated. However, the adding of gypsum had a beneficial effect on reducing the microcrack in the alkali-activated mortar.

• 한국지역사회생활과학회지
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• 제15권3호
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• pp.107-112
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• 2004

Many studies have showen that Letinus edodes have a reducing effects on blood pressure and lipid levels in animals with high blood pressure and hyperlipidemia. But the only cap has been on the market as goods and the stipe has been wasted. The price is very variable and is based on harvest time and the part of the plant currenty, there is not much information about the nutritional composition and bio-fuctional effects of Letinus edodes based on harvest time and part. Some farmers have been selling the powder seasoning by drying and pulverizing Letinus edodes including stipe to develop value added, late harvested Letinus edodes and its stipe these days. This study was conducted to investigate and compare the nutritional composition of Letinus edodes harvested at different times (early: E, late: L) and separated by part (cap: C, stipe: S). The 4 kinds of materials were named as early harvested cap (EC) and stipe (ES), and late harvested cap (LC) and stipe (LS) samples were obtained from Mungyeong City Agricultural Technology & Extension Center. The composition analysis of the nutrients in the 4 materials was conducted by using the AOAC method. The proximate components (moisture, protein, fat, fiber, ash, and carbohydrates), minerals and vitamin content were measured. Nutritional composition of Lentinus edodes did not show any significant difference between early and late harvested mushrooms. Nutritional compositions were different according to part. The results demonstrate that the late harvested stipe can also be used as a quality food material.

• 한국염색가공학회지
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• 제22권4호
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• pp.341-348
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• 2010

Sodium sulfate is commonly added in reactive dyebath in order to increase substantivity of the reactive dye to cellulose fiber by reducing repulsion between anionic dye and fiber. While sodium sulfate is mostly used in solid form, it is inconvenient to dissolve a large amount of powder sodium sulfate. Furthermore, if there is undissolved salt in dyebath it might cause unlevel dyeing. In this study, sodium sulfate in liquid or solid form was used in dyeing of cellulose fabric with reactive dyes of three primary color and the effect of type or amount of sodium sulfate on dyeing and fastness properties was investigated. When the amount of sodium sulfate rose to 30-50 g/l, K/S value of the dyed fabric markedly increased; further rise in sodium sulfate concentration resulted in slow increase in K/S value. For light color, optimum amount was about 30 g/l in solid form and 50-100 g/l in liquid form while, for medium to deep color, it was 50 g/l and 100-150 g/l in solid and liquid form, respectively. When using each optimum amount of salt in solid or liquid form for medium color, shape of dyeing curve as well as exhaustion was similar to each other. On the whole, similar color fastness results were obtained regardless of type or amount of sodium sulfate.

• 한국식품과학회지
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• 제52권5호
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• pp.487-494
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• 2020

본 연구는 비타민 및 무기질 등의 영양성분을 고루 함유하고 있을 뿐만 아니라 특히 식이섬유와 수용성 산성 다당류인 포피란이 풍부한 김 분말을 항산화성을 증진시킬 목적으로 크리스피 쌀 과자에 시리얼의 0, 1, 3, 5% 비율로 첨가하여 품질특성과 항산화능을 분석하였다. 환원당은 마른 김을 첨가함에 따라 크리스피 쌀 과자 중의 함량이 감소했다. 색도는 마른 김의 첨가량에 의해 명도와 적색도, 황색도 모두 유의적으로 감소하였다. 산화 방지 등의 항산화 활성을 가지는 색소 성분인 피코시아닌과 클로로필 함량 모두 마른 김 첨가량에 따라 유의적으로 증가했다. 항산화능은 총 페놀 함량, 플라보노이드 함량과 DPPH 라디칼 소거능 및 hydroxyl 라디컬 소거능 모두 마른 김 분말의 농도에 비례하여 우수해지는 것으로 나타났다. 감각평가 결과, 전반적인 만족감은 LP5 첨가군이 유의적으로 가장 높았고 대조군의 점수가 가장 낮았다. 크리스피 쌀 과자에 마른 김 분말을 첨가하는 것은 항산화능 증진에도 도움을 주어 크리스피 쌀 과자의 상품으로서의 가치를 높일 수 있을 것으로 사료된다.

• Journal of Pharmaceutical Investigation
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• 제22권4호
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• pp.267-279
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• 1992

Microencapsulations of amoxicillin and cephalexin, using Eudragit RS, RL, E, S and L were investigated. The microcapsules were prepared by the solvent evaporation process in liquid paraffin phase, which is based on dispersion of acetone/isopropanol containing the drug in liquid paraffin. Aluminium tristearate was used as an additive for the preparation of microcapsules. The size distribution, dissolution test and observation by SEM were examined. Good reproducibility in microcapsule preparation was observed. The microcapsules obtained were spherical and free-flowing particles. The dissolution rates of amoxicillin and cephalexin from the microcapsules were considerably decreased as compared with those from amoxicillin and cephalexin powder, respectively. As the dispersing agents (aluminium tristearate) increased, the particle size of microcapsules decreased and the dissolution rate increased. In order to control the release rate of drugs, microcapsules were prepared by mixing Eudragit RS/RL or Eudragit S/L. As Eudragit RL ratio in microcapsule of Eudragit RS/RL increased, the dissolution rate increased. As Eudragit L ratio in microcapsule of Eudragit S/L increased, the dissolution rate increased. Furthermore, the release rates of drugs from Eudragit RS/L or RS/polyelthylene glycol 1540 (PEG 1540) were examined. The dissolution rate of drugs increased with increasing of Eudragit L or PEG 1540 ratio. In conclusion, the release rates of drugs from Eudragit RS/RL or RS/PEG 1540 microcapsule could be controlled, and these microcapsules will be convenient for reducing frequency of administration.

• 터널과지하공간
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• 제26권5호
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• pp.441-453
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• 2016

본 연구에서는 분진을 저감시킬 수 있고 균질한 품질을 확보하는 데 적합한 2성분 박층 뿜칠 라이너(TSL)를 개발하고 그 성능을 평가하였다. 2성분 TSL 시작품의 인장강도는 분말 1성분 TSL보다 다소 낮게 나타났으나, 높은 연성으로 인해 파괴 시의 신장률이 크게 측정되었다. 이외에도 EFNARC(2008)에서 제시하고 있는 성능기준들을 만족하였으며, 두께 3 mm로 피복한 코팅 압축시험 결과, 재령 28일의 평균 압축강도가 50% 이상 향상되는 것으로 확인되었다. 시험타설을 통해 본 연구에서 개발된 2성분 TSL 시작품에 적합한 타설장비를 도출하였으며, 실제 현장시공을 통해 2성분 TSL 타설 시의 분진과 리바운드가 극히 미미함을 확인하였다. 2성분 TSL의 타설속도는 $60m^2/hr$이었으며 일반적인 뿜칠 방수 멤브레인과 비교할 때 빠른 경화 특성을 나타내었다.

• 한국미생물·생명공학회지
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• 제13권1호
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• pp.59-64
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• 1985

감귤과피를 미생물의 발효기질로 이용하기 위하여 우선 미생물이 생산하는 효소로서 감귤과피의 최적 당화조건을 실험한 결과는 다음과 같다. 감귤과피를 용이하게 당화시키는 균주로서 Aspergillus sp. GF 015를 분리 동정하였으며, 그 균주(菌株)의 효소생산(酵素生産)은 밀기울 고체배지에 질소원($NH_4NO_3$)무기염($KH_2PO_4$)을 각각 0.6, 0.05%의 농도로 첨가하여 $27^{\circ}C$에서 3일간 배양하였을 때가 가장 좋았다. 한편 효소(酵素)의 최적반응조건(最的反應條件)은 기질과 조효소액의 비율 15ml (97.5 unit)/g peel, pH 4.0, 반응온도 $45^{\circ}C$, 반응 12시간이 적당하였다. 그 결과 원료감귤과피에 대해 60.2% 환원당을 생성하여 76.3%의 당화율을 나타내었으며 총당에 대한 환원당의 비율이 95%로 상당히 저분자화 되어 있다. 또한 최종당화액중의 주요성분은 glucose, xylose, galacturonic acid였으며, 감귤과피 분해에 관하여는 주효소는 cellulase, pectinase였는데 xylanase 도 약간 관여하였다.

• 한국농공학회논문집
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• 제55권2호
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• pp.59-64
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• 2013

The present study is to evaluate physical and mechanical properties of porous concrete having non cement that mainly causes carbon emission. This study aims to explore eco-friendly concrete technology capable of reducing the amount of carbon emission due to the use of normal cement by substituting it with non cement porous concrete to which alkali-activator and blast-furnace slag powder are impregnated. As experimental variables, 5 %, 6 %, 7 %, 8 %, 9 % and 10 % of alkali-activator were substituted as binders and applied. Testing evaluated in this study were pH value, void ratio, compressive strength and residual compressive strength shown after being immersed in $H_2SO_4$ solution and $Na_2SO_4$ solution. The test results were compared with those tested with the use of porous concrete to which 400 $kg/m^3$ of unit cement amount was applied as binder. In consequence, it was concluded that; as for pH value, it was decreased than was the case in which cement was used, but increased with the more the use of alkali activator; as for void ratio and compressive strength, the mix proportion in which 9 % and 10 % of alkali activator were applied in terms of substitution ratio showed the result similar to the mixture in which 400 $kg/m^3$ of unit cement ratio was applied; and, as for residual compressive strength in the case of being immersed in $H_2SO_4$ solution and $Na_2SO_4$ solution, the compressive strength was increased, thus leading to improved chemical resistance.

• 한국가스학회지
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• 제22권4호
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• pp.1-6
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• 2018

IMO에서 규정하는 LNG 벙커링 선박용 연료 탱크 중 C형 가압탱크는 내외 2중 용기로 구성된 초저온 탱크에 $10^{-2}$ Torr 진공과 펄라이트 단열재가 충전되는 것이다. 그러나 이 단열방식은 LNG 기화량이 하루당 2.0 % 내외로 증발율이 커서 보다 단열효과가 좋은 탱크가 요구되어 진다. 본 연구에서는 내외탱크 사이에 고진공을 적용하고 외부탱크의 내벽체에 중간 단열로 펄라이트 진공단열을 적용하는 단열 방식을 새로이 고안하여 열해석을 수행하였다. 이의 장점으로는 진공 공간의 감소로 고진공 형성 시간을 크게 감소되고, 진공도 $10^{-4}$ Torr 이하에서 하루당 증발율이 0.16 %에 불과한 매우 효율이 높은 탱크 단열방식이 되었다. 만약 현재의 IMO C형 탱크의 진공펄라이트 단열에서 진공이 파괴되는 경우, C형 탱크는 하루당 4.9 %의 증발이 발생하고 새 고안 탱크는 5.23 %로 거의 동일하게 된다.

• 자원리싸이클링
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• 제14권3호
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• pp.48-54
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• 2005

FeCl$_3$용액으로 니켈프레임을 에칭하는 과정에서 발생한 폐액으로부터 철과 니켈을 분리, 회수하기 위해 용매추출과 환원실험을 수행했다. 추출제로 Alamine336을 사용하여 철과 니켈의 분리가 가능했으며, 유기상과 에칭폐액의 부피비가 7이상의 조건에서 99%의 철의 추출율을 얻었다. 0.01 M농도의 염산용액을 탈거액으로 사용하여 탈거액과 유기상의 부피비가 7인 조건에서 99%의 철 탈거율을 얻었다. 추출여액의 pH가 10.5이고 반응온도가 100$^{\circ}C$인 조건에서 환원제로 히드라진을 첨가하여 99%의 순도를 지닌 니켈 금속 분말을 얻었다. 용매추출과 화학환원을 이용하여 에칭폐액으로부터 니켈금속을 회수하고, 에칭액을 재생할 수도 있는 공정을 제시하였다.