• 대한기계학회논문집B
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• 제27권3호
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• pp.381-388
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• 2003

An experimental study was carried out to measure the heat transfer coefficient in flow boiling to mixtures of HFC-l34a and HCFC-123 in a uniformly heated horizontal tube. Tests were run at a pressure of 0.6 MPa and in the ranges of heat flux 1-50 kw/$m^2$, vapor quality 0-100 % and mass velocity 150-600 kg/$m^2$s. Heat transfer coefficients of mixture were less than the interpolated values between pure fluids both in the low quality region where the nucleate boiling is dominant and in the high quality region where the convective evaporation is dominant. Measured data of heat transfer are compared to a few available correlations proposed for mixtures. The correlation of Jung et. al. satisfactorily predicted the present data, but the data in lower quality was overpredicted and underpredicted the high quality data. The correlation of Kandlikar considerably underpredicted most of the data. and showed the mean deviation of 35.1%.

• 한국초지조사료학회지
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• 제12권4호
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• pp.211-217
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• 1992

This experiment was conducted over a 3-year period (1990-1992) to evaluate the production and quality of orchardgrass (Potomac)-red clover (Kenland) mixture when orchardgrass + red clover mixture was sown at seed rates of 20+0. 18+2, 16+4, 14+6 and 12+8 kg/ha. Total herbage dry matter, crude protein and digestible organic matter production and organic matter intake were markedly affected by increasing rcd clover seed rate, those increased with increasing red clovcr seed rate due to the cnhancernent of red clover percentage of total herbagc in all 3-year. but significant differences occured between the orchardgrass alone and orchardgrass-red clover mixture with a seed rate of 4,6 and 8 kg/ha red clover (P<0.01). But on the other hand increasing red clover seed rate increased red clover percentage in total herbage, the mean red clover percentage of total herbage at the last cutting ranged from 54 to 65% in first year. 58 to 60% in second year, and 62 to 69% in third year, particularly it was observed that red clover was sown at seed rates of 6 and 8 kg/ha for red clover sown dominated strongly as the cutting times were progressed. Considering the maintenance of good botanical composition balance and the enhancement of production and quality of herbage, the optimized seed rate for orchardgrass-red clover mixtures, 16 kg/ha orchardgrass and 4 kg/ha red clover seems to be considered adequate.

• 한국초지조사료학회지
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• 제16권4호
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• pp.275-282
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• 1996

This experiment was canied out to investigate the effect of pasture types(mixture and mono tall fescue pasture) and endophyte infection on the dry matter yield, forage quality and animal performance of pasture plants at the Experimental Field of Grassland and Forage Crops Division, National Livestock Research Institute, Suweon, in 1994. The results obtained are surmmarized as follows : DM yield of tall fescue monoculture was significantly higher(p<0.05) than that of mixture pasture, while DM yield of endophyte-infected pasture was significantly higher(p<0.05) than that of endophyte-free for two pasture types. Crude protein yield(CPY) of tall fescue monoculture was significantly higher(p<0.05) than that of mixture, and the higher CPY with endophyte-infect tall fescue for both pasture types resulted from higher DM yield of the pastures. NDF and ADF contents of pasture plants were not influenced by pasture types, and there was no difference for NDF and ADF contents between endophyte-infect and -free pasture mixture, however, those of pasture plants were increased with endophyte-infect tall fescue in monoculture. IVDMD of pasture plants was increased with mixture and endophyte-free tall fescue for both pasture types. IVDMD of pasture plants was greatly influenced by pasture types and endophyte infection. There were no significant differences in average daily gain of Korean native cattle between pasture types, but those of the cattle were significantly increased with endophyte-free tall fescue for both pasture types(p<0.05). Based on the results of this experiment, it is suggested that a slightly more forage yield could be obtained , from monoculture and endophyte-infected tall fescue. However, liveweight gain was increased by mixture and endophyte-free tall fescue with good quality.

• 한국초지조사료학회지
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• 제22권4호
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• pp.233-240
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• 2002

겨울피복작물로 재배되는 헤어리베치는 토양과 동반작물에 질소를 공급한다. 본 시험은 겨울철에 헤어리베치와 사료작물을 혼파할 때 수량 및 사료가치의 개선정도를 알아보기 위해 3년간 수행되었으며 그 결과를 요약하면 다음과 같다. 호밀-헤어리베치 혼파시 호밀의 초장은 다소 감소하였으며 혼파에 따른 호밀 출수기는 큰 차이가 없었다. 건물 함량은 헤어리베치의 비율이 늘어날수록 낮아졌으나 파종방법에 따른 유의 적인 차이는 없었다. 조단백질 함량도 베치가 21.7∼21.8%로 호밀의 15.3∼15.8%에 비해 높았으며 혼파시 헤어리베치 비율의 증가에 따라 조단백 함량이 더 높아졌다. ADF, NDF 함량은 혼파구에서 호밀단파구보다 낮게 나타났다. 건물소화율 및 TDN 함량은 반대의 경향을 보였다. 건물수량은 호밀단파구에서 가장 높았으나 호밀단파구와 호밀 2/3+베치 1/3 구와의 유의 적인 차이는 없었다(P<0.05). 조 단백질 수량에서도 호밀단파구와 호밀 2/3+베치 1/3구는 유의성이 없었다. 토양중의 총 질소 함량은 재배후 0.06∼0.08% 정도 향상되는 것으로 나타났다. 이상의 결과를 종합하여 볼 때 호밀 2/3+베치 1/3구는 호밀 단파구에 비해 생산성 및 품질이 우수하여 토양보존과 생산성측면에서 권장되는 재배방법으로 판단되었다.

• 한국도로학회논문집
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• 제20권1호
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• pp.69-76
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• 2018

PURPOSES : This study determined the optimal usage rate of RAP (reclaimed asphalt pavement) using cold central-plant recycling (CCPR) on a road-surface layer. In addition, a mixture-aggregate gradation design and a curing method based on the proposed rate for the surface-layer mix design were proposed. METHODS : First, current research trends were investigated by analyzing the optimum moisture content, mix design, and quality standards for surface layers in Korea and abroad. To analyze the aggregate characteristics of the RAP, its aggregate-size characteristics were analyzed through the combustion asphalt content test and the aggregate sieve analysis test. Moreover, aggregate-segregation experiments were performed to examine the possibility of RAP aggregate segregation from field compaction and vehicle traffic. After confirming the RAP quality standards, coarse aggregate and fine aggregate, aggregate-gradation design and quality tests were conducted for mixtures with 40% and 50% RAP usage. The optimum moisture content of the surface-layer mixture containing RAP was tested, as was the evapotranspiration effect on the surface-layer mixture of the optimum moisture content. RESULTS : After analyzing the RAP recycled aggregate size and extraction aggregate size, 13-8mm aggregate was found to be mostly 8mm aggregate after combustion. After using surface-chipping and mixing methods to examine the possibility of RAP aggregate segregation, it was found that the mixing method contributed very little for 3.32%, and because the surface-chipping method applied compaction energy directly as the maximum assumption the separation ratio was 15.46%. However, the composite aggregate gradation did not change. Using a 40% RAP aggregate rate on the surface-layer mixture for cold central-plant recycling satisfied the Abroad quality standard. The optimum moisture content of the surface-layer mixture was found to be 7.9% using the modified Marshall compaction test. It was found that the mixture was over 90% cured after curing at $60^{\circ}C$ for two days. CONCLUSIONS : To use the cold central-plant recycling mixture on a road-surface layer, a mixture-aggregate gradation design was proposed as the RAP recycled aggregate size without considering aggregate segregation, and the RAP optimal usage rate was 40%. In addition, the modified Marshall compaction test was used to determine the optimum moisture content as a mix-design parameter, and the curing method was adapted using the method recommended by Asphalt Recycling & Reclaiming Association (ARRA).

• 한국초지조사료학회지
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• 제18권4호
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• pp.311-316
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• 1998

본 시험은 충남대학교 농과대학 초지시험포장에 1995년 9월부터 1998년 5월까지 속간교잡종인 Festulolium braunii (품종, Paulita)의 국내 보급가능성을 타진하고자 3처리의 혼파유형 (1) Festulolium braunii (FB, 파종비율 50%)+orchardgrass(OG, 50%), (2) Festulolium braunii (FB, 80%)+red clover (RC, 20%) 및 (3) Festulolium braunii (FB, 20%)+orchardgrass(OG, 50%)+tall fescue(TF, 20%)+white clover(WC, 10%)을 두어 난괴법 4반복으로 건물수량과 품질을 비교하였으며 얻어진 결과는 다음과 같다. 건물수량은 처리간에 유의적인 차이는 없었으나 FB+RC 초지가 다른 혼파유형에 비하여 약간 많았다. CP 함량은 FB+RC 초지가 다른 혼파유형에 비하여 높았으며(P<0.05), 반대로 NDF와 ADF 함량은 다른 혼파유형에 비하여 오히려 낮은 결과를 가져왔다(P<0.05). CP와 DDM 수량은 FB+RC 초지가 다른 혼파유형에 비하여 높은 결과를 나타내었다(P<0.05). 97년의 마지막 예취시기에 조사한 식생비율은 모든 혼파유형에서 FB의 식생비율이 51~58%로 높게 유지되었다. 이상의 결과를 종합할 때 FB는 다른 초종과 혼파가능성은 충분하다고 하겠으며, 그 중 RC와 혼파하는 것이 가장 좋은 결과를 얻었다.

• 한국조리학회지
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• 제14권4호
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• pp.1-13
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• 2008

The antioxidant activity and quality characteristics of bread made from waxy black rice flour(WBRF) and green tea powder were investigated. The bread was manufactured with 1% of green tea powder and 10, 20, 30 or 40% of WBRF(w/w). The group of 40% of WBRF and green tea powder significantly showed the highest bread weight and volume. Lightness(L value) and yellowness(b value) decreased, but redness(a value) increased with increasing WBRF contents in mixture. Hardness, gumminess and chewiness were the lowest in the control group, but springiness was the lowest in the group of 40% of WBRF and 1% of green tea powder. The sensory scores of appearance, external and crumb color, grainy in the group of 40% of WBRF and 1% of green tea powder were the significantly lowest. Overall acceptabilities of the groups of 10% and 30% of WBRF with 1% of green tea powder were not significantly different from the control group. The group of 40% of WBRF and 1% of green tea powder showed the highest DPPH radical scavenging effect and TEAC content. Thus, if the mixture of green tea powder and WBRF would be used, it might be proper to use 1% of green tea powder and 10% of WBRF mixture considering the quality and antioxidant activity of bread.

• 한국식품영양과학회지
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• 제29권2호
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• pp.241-247
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• 2000

The possibility of buckwheat-wheat flour mixture as bread was studied by adding 10, 20, and 30% of buckwheat to wheat flour. To improve bread-making quality of the mixture, gluten, ascorbic acid, and hydroxy propyl methyl cellulose (HPMC) were added to 30% buckwheat-wheat flour and sensory evaluation was also exercised on it. The weight of bread increased but the volume of that decreased as the percentage of buckwheat to wheat flour increased, and improved bread-making quality by adding gluten, ascorbic acid, HPMC to 30% buckwheat-wheat composite flour. When it comes to color, color of the bread got darker as the percentage of buckwheat increased, got brighter when gluten and HPMC were added and showed little difference when ascorbic acid was added. Texture of bread increased in maximum weight, strength, hardness but decreased in springiness and cohesiveness. The use of additives showed influence to the some results. In terms of the aging process, enthalpy increased with storage time, and it could be slowed down by the use of the additives. The sensory evaluation shwoed that 10% buckwheat-wheat bread was most excellent, 20% bread was similar to other bread made from wheat flour, and the bread made by mixing additives were better than just 30% buckwheat-wheat flour in terms of quality.

• 한국건설순환자원학회논문집
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• 제4권3호
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• pp.299-306
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• 2016

본 연구에서는 동일 작업성 조건에서 저품질 잔 굵은 골재가 콘크리트의 공학적 특성에 미치는 영향을 실험적으로 분석 하고자 하였는데, 그 결과를 요약하면 다음과 같다. 먼저, 슬럼프 및 공기량을 단위수량과 AE제 혼입량 변화로 동일하게 배합설계 하였다. 따라서, 양호한 품질의 골재를 사용한 배합에 비해 저품질의 골재 사용시 불량의 입도 및 미립자량 등의 영향으로 단위수량 및 AE제 혼입량이 각각 약 18%, 98% 증가하는 경향이 나타났다. 압축강도의 경우는 양호한 품질의 부순 굵은 골재를 사용한 배합에 비해 저품질의 발파석 굵은 골재를 사용한 배합에서 특히, 발파석 마사토 및 해사와 같은 저품질 잔골재와 복합될 때 20~35% 까지 저하하는 결과를 나타내었다. 또한, 저품질 잔 굵은 골재를 사용한 콘크리트인 경우는 압축강도뿐만 아니라 탄성계수와 내구성으로 동결융해, 건조수축, 탄산화 및 염해저항성 측면에서도 크게 저하하여 그 심각이 문제시 되었다. 따라서 저품질 골재를 순환자원으로 활용하고자 할 때에는 물씻기, 혼합골재에 의한 입도 조정 등 별도의 처리를 거쳐 사용하거나 혹은 사용을 철저히 규제하는 특별한 대책이 수립 되어야 할 것으로 사료된다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 춘계 학술발표회 제20권1호
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• pp.401-404
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• 2008

본 연구는 국내 건설현장 여건에 적합한 고강도 레디믹스트 콘크리트의 제조 및 품질관리기술의 체계적 확립을 위하여, 40${\sim}$60MPa급 고강도 콘크리트의 배합설계를 예측할 수 있는 추정식을 실험으로 산출하고, 이를 적용하여 고강도 콘크리트 배합설계 프로그램을 개발한 것이다. 프로그램의 사용 언어는 Visual Basic, MS-SQL을 사용하였고, 실험 결과를 토대로 산출한 수식을 이용한 고강도 콘크리트의 배합설계 계산 기능, 데이터의 저장 및 출력기능, 서버를 통한 데이터 공유기능 등을 갖추고 있어, 고강도 레디믹스트 콘크리트의 제조 및 품질관리 기술의 체계적 확립에 이바지 할 것으로 사료된다. 다만, 본 프로그램은 실험실 조건을 기본으로 제작되어, 초기에는 고강도 콘크리트 배합설계의 기초자료로 활용할 수 있을 것이나, 추후 공유되는 공장별 배합설계 자료를 이용하여 업그레이드한다면 각 공장의 특성에 맞는 고강도 레디믹스트 콘크리트의 제조 및 품질안정성에 기여할 것으로 판단된다.