• Journal of Biosystems Engineering
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• 제34권5호
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• pp.342-350
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• 2009

Currently TMR feed produced in commercial plant is one of the major source to feed cattle for both beef and dairy farm. However, because of lack of cutting and mixing system for utilizing domestic produced firmly baled round roughage in commercial TMR plant, these commercial TMR feed can not satisfy to farmers both in quality and price points of view. In order to solve these problems, a farm group size TMR plant model was developed in this study. The model plant was consist of round bale receiving and cutting system, pneumatic conveying system for transfer the roughage which was cut at the cutter to TMR mixer through pneumatic conveyor, TMR mixer enable to soften the stiff rice strew and to mix with other ingredients, finished feed bin which can be transfer to either packing system or individual farm, packing system by tycon bag which contains 400 kg unit and bulk unloading system to individual farmer. Also, a simulation model ARENA was applied to the model system in order to evaluate and check the production rate in each unit process and operation rate of total system and to find out if there are any clogged unit system obstructing the smooth flow of the total process flow. Processing cycle for produce one batch of the model plant was less than 30 minutes. Thus, it will take less than four hours for producing 16 tons per day equivalent to 1,000 beef cattle's daily feed.

• 한국가금학회지
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• 제12권1호
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• pp.45-50
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• 1985

본 연구는 우리나라의 계란 유통현황을 조사하기 위하여 서울근교, 대전근교, 광주근교, 부산근교에 소재하고 있는 수집상 8개소, 도배상 16개소, 소매상 12개소 및 슈퍼마켓 6개소를 대상으로 설문서를 작성하여 설문조사하였고 그 결과를 계란의 유통규격 설정을 위한 기초자료를 얻고자 실시하였다. 1. 계란의 중량별 구분은 생산자가 주로 실시하며 이 계란의 유통가격은 유통단계별로 2-3원 차가 있었으며 왕란 및 특란은 가정소비가 많았고 대란은 음식점과 가정집에서 그리고 중란과 소란은 음식점에서 주로 소비하고 있다. 2. 소비자 측면에서 볼 때 갈색란을 개당 1.5원씩 더 주고 구입하는 경향이 있었고 중량별 구분은 대체로 믿고 있었다. 3. 소비자의 계란 1회구입량은 30개 주였으며 포장할 경우 10개 단위의 포장을 희망하고 있으며 10개의 포장비용은 10-20원이었고 포장판매를 원하고 있는 비율이 55-64% 정도나 되었다. 4. 유통상인이 구입한 계란은 7일이내에 대부분 판매하고 있으며 계란이 가장 많이 판매되는 계절은 가을이며 G. P센타가 필요하다고 생각하는 비율이 36.4%나 되었다.

• 한국안광학회지
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• 제11권4호
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• pp.323-327
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• 2006

본 연구는 국내 안경렌즈의 포장 표시사항에 관한 실태와 그의 신뢰성에 대하여 조사하였다. 실험에 사용한 Sample은 8개회사 총 396개의 안경렌즈를 사용하였으며. 굴절률은 각각 1.55~1.56, 1.60~1.61 그리고 1.67의 세 가지로 분류하였다. 표기율에서 A사와 B사는 80% 표기율을 나타내었으나, 2개 사는 각각 52.1%와 56.9%만의 표기율을 나타내었다. 포장표시 사항에 관해서 대부분의 회사들은 비교적 적은 표기율을 사용하고 있음을 알 수 있었다. 기재된 굴절력과 측정값을 비교한 실험에서는 약간의 차이만을 나타내었다.

• 한국해안·해양공학회논문집
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• 제26권2호
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• pp.103-111
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• 2014

크기가 작은 다수의 부이들이 원형으로 배열되어 있을 때 부이를 통한 추출 파워를 포텐셜이론 통하여 살펴보았다. 부이의 크기와 배열 간격이 수심과 파장 그리고 설치면적의 반경에 비하여 작다는 가정 아래에서 다수부이로 채워진 수면에서의 경계조건식을 유도하고 이를 포함한 경계치문제를 고유함수전개법을 이용하여 해석하였다. 추출 파워와 입사파 에너지의 비인 취득 폭을 packing ratio, 배열 반경, 그리고 PTO 감쇠계수를 바꿔가면서 살펴보았다. 또한 다수의 소형 부이를 원형 배열하였을 때 추출된 파력이 같은 잠긴 체적을 갖는 대형 단일 부이보다 효율적임을 계산을 통하여 밝혔다.

• Elastomers and Composites
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• 제6권1호
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• pp.71-81
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• 1971

The intention of this study is to investigate the properties of polymer blend, NBR/PVC vulcanizates and blending procedures such as roll-mixing temperatures and sequences for polymer blending of NBR and PVC(resin type). The results obtained are as follows: 1. The roll temperature applied for polymer blending is around $150^{\circ}C$. At this temperature region, the degradation of rubber stock, which may be caused by heat, can be minimized and mill processing in practical application in industries can also be facilitated. 2. It is obviously necessary that a small amount of plasticizers should be added to the stock for improving processibility of roll mixing and physical properties. 3. On roll-mixing sequence, it is more effective that PVC compounded with plasticizer is added to NBR milled on hot roll. 4. The vulcanizates of the blends with different degree of polymerization of PVC ale similar to one another in properties. 5. NBR/PVC(70/30) blends shows the better physical characters than eve,-made foreign latex blend except abrasion-resistance. 6. As PVC addition ratio is increased, the physical properties such as resistance to ozone, tear, heat and oil and tensile strength, modulus, hardness have also improved, on the other hand, tension set and rebound character decreased. 7. The curve of ultimate elongation have point of inflection at the ratio of $30\sim40$ part of PVC. 8. While CR is blended, the physical properties such as brittle point, rebound and resistance to oil in high temperature have improved. 9. Polymer blend of NBR and domestic PVC is applied for the industrial utility such as rubber sole and heel, electric wire cover and oil-resistant packing, coating and gasket, printing roll, film for food packing etc.

• Elastomers and Composites
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• 제49권4호
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• pp.305-312
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• 2014

대부분 군사용 초음속 전투기는 후기 연소기를 사용한다. 후기 연소기는 초음속 비행, 이륙, 전투 상황에 대해 비상 임무 수행을 가능하게 하는 중요한 역할을 한다. 최근 전투기 J85-GE-21 터보제트 엔진 후기 연소기 연료펌프의 내부 피스톤 패킹고무에서 반복적인 연료 누출 결함이 발생하였다. 이러한 결함은 두 제조사 중 한 제조사의 부품에서만 발생하였다. 따라서, 결함발생 원인을 제조사가 상이한 정상품 및 결함품에 대하여 다양한 비교 분석방법을 통하여 조사하였다. 결함분석에는 팽윤 또는 팽윤도, 총 황함량, 폴리머 확인, 카본블랙 함량 및 표면적, 경도와 같은 분석방법이 적용되었다. 결론적으로, 반복적인 연료 누출 결함의 주요 원인은 보강제 카본블랙의 함량 미달로 확인되었으며, 더불어 표면적이 작은 카본블랙과 함량이 낮은 황 적용이 결함원인에 부가적인 영향을 준 것으로 확인되었다.

• Bulletin of the Korean Chemical Society
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• 제32권4호
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• pp.1133-1137
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• 2011

Ordered array of gold nanoparticles (Au NPs) over ITO glass was investigated in terms of ITO pretreatment, particle size, and diamines with different chain length. Owing to the indium-tin-oxide (ITO) layer coated on the glass, the substrate surface has a limited number of hydroxyl groups which can produce functionalized amine groups for Au binding, which resulted in the loosely-packed array of Au NPs on the ITO surface. Diamine ligand as a molecular linker was introduced to enhance the lateral binding of adjacent Au NPs immobilized on the amine-functionalized ITO glass, consequently leading to the densely-packed array of Au NPs over the ITO substrate. The molecular bridging effect was strengthened with the increase of chain length of diamines: C-12 > C-8. The packing density of small Au NPs (< 40 nm) was significantly increased with the increase of C-8 diamine, but large Au NPs (> 60 nm) did not produce densely-packed array on the ITO glass even for the dosage of C-12 diamine.

• 대한산업공학회지
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• 제27권4호
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• pp.424-431
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• 2001

This paper is concerned with the unconstrained two-dimensional cutting problem of cutting small rectangles (products), each of which has its own profit and size, from a large rectangle (material) to maximize the profit-sum of products. Since this problem is used as a sub-problem to generate a cutting pattern in the algorithms for the two-dimensional cutting stock problem, most of researches for the two-dimensional cutting stock problem have been concentrated on solving this sub-problem more efficiently. This paper improves Hifi and Zissimopoulos's recursive algorithm, which is known as the most efficient exact algorithm, by applying newly proposed upper bound and searching strategy. The experimental results show that the proposed algorithm has been improved significantly in the computational amount of time as compared with the Hifi and Zissimopulos's algorithm.

• 한국경영과학회지
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• 제38권1호
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• pp.61-67
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• 2013

We consider a problem of grouping orders for batch processing that arises in production systems where customer orders are processed in batches. This problem can be viewed as a variant of bin packing problem where items can be split and a pair of items can be placed in a bin when the items are compatible with each other. In this paper, we consider a special case that at most two different items can be placed in a single bin and the size of every item is at most the size of a bin.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 1999년도 봄 학술발표회 논문집(I)
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• pp.349-354
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• 1999

Specialty cellulose fibers processed for the reinforcement of concrete offer relatively high levels of elastic modulus and bond strength. The hydrophilic surfaces of specialty cellulose fibers facilitate their dispersion and bonding in concrete. Specialty cellulose fibers have small effective diameters which are comparable to the cement particle size, and thus promote close packing and development of dense bulk and interface microstructure in the matrix. The relatively high surface area and the close spacing of specialty cellulose fibers when combined with their desirable mechanical characteristic make them quite effective in the suppression and stabilization of microcracks in the concrete matrix. The properties of fresh mixed specialty cellulose fiber reinforced concrete and the contribution of specialty cellulose fiber to the restrained shrinkage crack reduction potential of cement composites at early age and theirs evaluation are presented in this paper. Results indicated that specialty cellulose fiber reinforcement showed an ability to reduce the total area significantly (as compared to plain concrete and polypropylene fiber reinforced concrete.