• Asian-Australasian Journal of Animal Sciences
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• 제13권12호
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• pp.1699-1707
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• 2000

Thirty-one multiparous Bos indicus${\times}$Bos taurus cows were offered concentrate supplements based on (1) 2 kg wheat bran; (2) 4 kg wheat bran; and (3) concentrate (30 maize: 67 wheat bran) at 0.5 kg per 1.0 kg milk produced, in a one year study in India. All supplements also contained 2 parts of a mineral mixture and 1 part salt. Cows were allocated to treatments at calving on parity (2nd and 3rd calf) with 13, 8 and 10 cows respectively in treatments 1, 2 and 3. They were individually fed for whole lactation, the basal diet being ad libitum berseem clover plus 2 kg wheat straw in the cool season/winter (period 1) and chopped maize in summer (period 2). Diets with berseem offered TDN and CP contents of 67.6, 18.2; 65.5, 16.8; and 67.5, 16.8 percent; and with maize fodder 62.6, 12.0; 62.6, 12.5; and 63.3, 12.5 percent for treatments 1, 2 and 3, respectively. Total dry matter (DM) intakes (1) 9.9 kg, (2) 10.9 kg and (3) 11.1 kg DM/day and intake of nutrients (TDN, CP) increased with level of supplementation (p<0.01), but effects of treatment on animal performance were not significant. Cow milk yields averaged (1) 7.9 kg, (2) 8.1 kg and (3) 8.8 kg milk/day (p>0.05) for lactation lengths of 252, 270 and 220 days (p>0.05) and cows gained +7.3; +8.1; and +12.0 kg respectively over their lactation (p>0.05). Wheat bran was used effectively as the sole energy component in concentrates for lactating dairy cows. Its use could potentially reduce feed costs and demands for cereal grain. Reduced concentrate levels may be considered if green forages of high nutrient content are fed ad libitum. Associated economic advantages or disadvantages require further evaluation.

• Nuclear Engineering and Technology
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• 제45권6호
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• pp.731-744
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• 2013

Energy security is a topic of high importance to many countries throughout the world. Countries with access to vast energy supplies enjoy all of the economic and political benefits that come with controlling a highly sought after commodity. Given the desire to diversify away from fossil fuels due to rising environmental and economic concerns, there are limited technology options available for baseload electricity generation. Further complicating this issue is the desire for energy sources to be sustainable and globally scalable in addition to being economic and environmentally benign. Nuclear energy in its current form meets many but not all of these attributes. In order to address these limitations, TerraPower, LLC has developed the Traveling Wave Reactor (TWR) which is a near-term deployable and truly sustainable energy solution that is globally scalable for the indefinite future. The fast neutron spectrum allows up to a ~30-fold gain in fuel utilization efficiency when compared to conventional light water reactors utilizing enriched fuel. When compared to other fast reactors, TWRs represent the lowest cost alternative to enjoy the energy security benefits of an advanced nuclear fuel cycle without the associated proliferation concerns of chemical reprocessing. On a country level, this represents a significant savings in the energy generation infrastructure for several reasons 1) no reprocessing plants need to be built, 2) a reduced number of enrichment plants need to be built, 3) reduced waste production results in a lower repository capacity requirement and reduced waste transportation costs and 4) less uranium ore needs to be mined or purchased since natural or depleted uranium can be used directly as fuel. With advanced technological development and added cost, TWRs are also capable of reusing both their own used fuel and used fuel from LWRs, thereby eliminating the need for enrichment in the longer term and reducing the overall societal waste burden. This paper describes the origins and current status of the TWR development program at TerraPower, LLC. Some of the areas covered include the key TWR design challenges and brief descriptions of TWR-Prototype (TWR-P) reactor. Selected information on the TWR-P core designs are also provided in the areas of neutronic, thermal hydraulic and fuel performance. The TWR-P plant design is also described in such areas as; system design descriptions, mechanical design, and safety performance.

• 대한용접접합학회:학술대회논문집
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• 대한용접접합학회 2010년도 춘계학술발표대회 초록집
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• pp.51-51
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• 2010

Recently just as in the automobile industry, shipbuilders also try to reduce material consumption and weight in order to keep operating costs as low as possible and improve the speed of production. Naturally industry is ever searching for welding techniques offering higher power, higher productivity and a better quality. Therefore it is important to have a details research based on the various welding process applied to steel and other materials, and to have the ability both to counsel interested companies and to evaluate the feasibility of implementation of this process. Submerged-arc welding (SAW) process is usually used about 20% of shipbuilding. Similar to gas metal arc welding(GMAW), SAW involves formation of an arc between a continuously-fed bare wire electrode and the work-piece. The process uses a flux to generate protective gases and slag, and to add alloying elements to the weld pool and a shielding gas is not required. Prior to welding, a thin layer of flux powder is placed on the work-piece surface. The arc moves along the joint line and as it does so, excess flux is recycled via a hopper. Remaining fused slag layers can be easily removed after welding. As the arc is completely covered by the flux layer, heat loss is extremely low. This produces a thermal efficiency as high as 60% (compared with 25% for manual metal arc). SAW process offers many advantages compared to conventional CO2 welding process. The main advantages of SAW are higher welding speed, facility of workers, less deformation and better than bead shape & strength of welded joint because there is no visible arc light, welding is spatter-free, fully-mechanized or automatic process, high travel speed, and depth of penetration and chemical composition of the deposited weld metal. However it is difficult to application of thin plate according to high heat input. So this paper has been focused on application of the field according to SAW process for thin plate in ship-structures. For this purpose, It has been decided to optimized welding condition by experiments, relationship between welding parameters and bead shapes, mechanical test such as tensile and bending. Also finite element(FE) based numerical comparison of thermal history and welding residual stress in A-grade 3.2 thickness steel of SAW been made in this study. From the result of this study, It makes substantial saving of time and manufacturing cost and raises the quality of product.

• 한국컴퓨터그래픽스학회논문지
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• 제18권2호
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• pp.1-8
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• 2012

HDR (high dynamic range) 영상은 일반적인 디지털 영상보다 훨씬 더 넓은 수치 범위로 빛의 노출을 저장한다. 따라서 실세계에 존재하는 광원들에 의해 표현되는 특정 장면에 내재된 빛의 세기를 매우 정확하게 저장할 수 있다. 이러한 HDR 영상을 빠르고 정확하게 촬영할 수 있는 전문가용 HDR 카메라가 개발되었으나 높은 가격으로 인해 아직까지 일반적인 작업환경에서 이용하기에는 어려움이 있다. 낮은 비용으로 HDR영상을 생성하는 일반적인 방법은 범용 디지털카메라를 이용해 동일한 장면을 서로 다른 노출로 반복 촬영하고 상용 소프트웨어에서 이들을 입력받아 하나의 HDR 영상으로 변환하는 것이다. 하지만 이러한 방법은 복잡하고 정확한 카메라 보정을 필요로 하는 작업이다. 더욱이 이 방법을 이용해 고급 영상 콘텐츠 제작을 위한 HDR 환경 맵을 생성하는 경우 더 섬세한 수작업과 시간 투자를 필요로 한다. 본 논문에서는 이러한 촬영 작업을자동화 하기위해 개발된 HDR 파노라마 환경 맵 제작 시스템에 대해 자세히 설명한다. 그리고 영상기반 라이팅 기법을 적용하여 3D 그래픽 모델을 2D 배경영상에 삽입하는 사실적합성 작업에서 본 시스템이 효과적으로 이용될 수 있음을 실제 사례를 통해 보인다.

• 한국경제지리학회지
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• 제4권2호
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• pp.79-96
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• 2001

일반적으로 클러스터는 첨단기술의 제조업, 특히 IT기반 산업이나 수직적으로 통합된 장인산업 등으로 이루어지며, 대개 벤처자본과 엔젤자몬 등과 함께 다양한 정부의 지원과 사업 인프라를 통해 이르게 성장하는 특성을 보인다. 대부분의 클러스터연구는 이러한 지식기반산업의 군집과 혁신의 특성을 연구한다. 이 연구는 서울 중심부에서 발달한 새로운 형태의 산업클러스터의 특성을 분석한다. 서울의 전형적인 도심주변부로서 지역의 쇠퇴와 교통 혼잡, 환경문제가 심각한 청계천로상의 전문상가로는 지식기반산업이 아니라 의류와 패션산업의 군집으로 인해 가장 역동적이고 혁신적인 지역으로 변모하고 있다. 이러한 새로운 형태의 산업클러스터의 특성과 사회적 자본의 형성에 대한 연구는 클러스터이론과 내분도시의 변화에 대해 새로운 시각을 제시할 수 있을 것이다. 이 글에서 먼저 청계천로 전문상가로의 성장에 대해 간략히 고찰한 후, 새로운 형태의 클러스터의 제도적, 공간적 특성을 살펴본다. 또한 생산-분배-판매-장소소비 등이 한 곳에서 이루어지는 청계천 클러스터의 핵심 구성요소들의 발달과정을, 지역적 네트워킹, 사회적 자본, 제도화, 장소성에 기반한 사회 문화경제적 기제 등의 개념으로 설명한다. 마지막으로 서울의 새로운 산업 클러스터 발전에 대한 전망과 향후 연구과제를 제시한다.

• 한국전자파학회논문지
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• 제29권4호
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• pp.277-284
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• 2018

본 논문은 향후 투명 디스플레이, 스마트글래스(smart glass) 등의 그 활용도가 증가 추세에 있는 투명전극과 관련된 논문이며, 본 논문에서는 투명 안테나 등의 투명 고주파 수동소자 설계 시, 투명 디스플레이 등에 가장 많이 사용되고 있는 ITO(Indium-Tin-Oxide)을 이용한 박막형(thin film type) 투명전극의 낮은 전기적 특성(면저항>$5({\Omega}/sq)$)으로 인한 성능저하를 개선하고자, 고주파 소자에 가장 일반적으로 사용되는 도체인 구리선(copper wire)으로 구현되는 정방형 메탈메쉬(square metal mesh)를 이용하여 투명전극을 구현하고, 이를 기본 단위로 하여 투명 패치 안테나를 구현하였고, 그 성능을 비교 분석하였다. 본 논문에서는 투명전극의 기본 설계 블록인 정방형 메탈메쉬의 광학적 특성(광 투과도) 및 전기적 특성(면저항)을 측정 및 분석하였고, 이를 이용하여 투명 패치 안테나를 설계, 측정, 분석하였다. 또한, 정방형 메탈메쉬는 광 투과도를 높이기 위해 얇은 구리선(w=0.2 mm)을 사용하였으며, 망(mesh) 크기(l=1, 2 mm)에 따른 광 투과도와 안테나 성능(방사이득, 방사패턴)과의 관계를 분석하였다. 투명 안테나 성능 측정 결과, 안테나 성능은 정방형 메탈메쉬의 광학적 특성과 반비례하며, 실제 활용 시에는 광학적 특성, 전기적 특성, 제작비용을 종합적으로 고려하여, 응용에 따른 투명 안테나의 활용이 필요하다.

• 한국산학기술학회논문지
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• 제18권10호
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• pp.499-504
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• 2017

이동형 전파측정시스템은 차량 탑재형으로, 단독임무수행이 가능하도록 설계되었다. 이동측정의 업무 특성상 기동성 확보가 필요하며, 이를 위해서는 안테나의 배치와 매립 방법에 대해 고려할 필요가 있다. 본 논문에서는 이동형 전파측정시스템의 방향탐지 정확도 측정방법개선을 위한 설계를 소개한다. 서보모터(Servo Motor)와 슬립링(Slip-Ring)을 활용하여 방향탐지안테나 마스트를 자체적으로 360도 회전하는 방법에 대해 분석하였고, 기동성과 내구성을 고려했을 때 슬립링을 활용하여 마스트를 회전시키는 방법으로 설계하였다. 이러한 설계를 통해 방향탐지 정확도 측정방법에서 턴테이블(Turn-Table)이 필요 없게 되어 지역적 의존성을 제거하였다. 즉, 전파무반사환경을 충족하는 챔버나, EUT를 공중에 매달리게 만든 후 시험을 수행할 필요가 없어지게 된다. 또한 턴테이블상의 피실험체의 영점조정 및 피실험체의 마운트 절차가 단축되어 생산성의 향상을 꾀할 수 있다. 내구성 강화를 위해 RF케이블 조립체를 마스트 내부로 포선하는 방법을 사용하였고, 설계내용에 따라 RF케이블의 길이가 짧아지는 효과로 인해 케이블 손실의 개선효과를 볼 수 있다. 또한 같은 현상으로 인해 시스템 전체의 무게가 줄어들어 기동성의 향상도 꾀할 수 있다.

• Asian-Australasian Journal of Animal Sciences
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• 제33권1호
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• pp.157-165
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• 2020

Objective: The objective of this study was to compare the quality of dry-aged beef from cull Hanwoo cows slaughtered at 60 or 80 months old. Methods: A total of eight cull Hanwoo carcasses with a quality grade of 3 (low-grade) were selected and divided into two age groups: 63.5±2.5 months old (n = 4) and 87.8±4.5 months old (n = 4). Whole longissimus thoracis et lumborum from the 11th rib to the last lumbar vertebrae, including the back fat, was removed from the carcass at 24 h postmortem and aged for 50 days in darkness at a temperature of 2℃±1℃, a relative humidity of 85% and an air flow of 2 m/s. The sampling was performed aseptically after 0, 20, 24, 40, and 50 days of aging. Results: Regardless of the aging period, aging increased the lightness (p<0.05), redness (p<0.05) and yellowness (p<0.05) at initial blooming (90 min after slicing) and the overall acceptance (p<0.05). No further tenderization effect was found after 20 days of aging, but aging for 50 days significantly increased the lipid oxidation (p<0.05). The generation of aroma volatiles in the roast steak from aged samples was higher (p<0.05) than that of non-aged samples. No significant effect of age at slaughter was found on the color, pH, water-holding capacity, cooking loss, shear force value, bacterial counts, volatile basic nitrogen, consumer acceptance, lipid oxidation, fatty acid composition or aroma volatiles. Conclusion: The quality of dry-aged beef obtained from cull Hanwoo cows slaughtered at either 60 or 80 months old with similar quality grade was comparable and extending dry aging for more than 40 days is not recommended considering the costs and further lipid oxidation.

• Asian-Australasian Journal of Animal Sciences
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• 제33권4호
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• pp.623-633
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• 2020

Objective: Substituting starch with digestible fiber (dF) can improve digestive health of rabbits and reduce costs. Therefore, it is necessary to develop a criterion for dF and starch supply. Effects of the dietary dF-to-starch ratio on pellet quality, growth and cecal microbiota of Angora rabbits were evaluated. Methods: Five isoenergetic and isoproteic diets with increasing dF/starch ratios (0.59, 0.66, 0.71, 1.05, and 1.44) were formulated. A total of 120 Angora rabbits with an average live weight of 2.19 kg were randomly divided into five groups with four replicates. At the end of 40 day feeding trial, cecal digesta were collected to analyse microbiota. Results: The results showed that the dF/starch ratio had linear effects on pellet variables (p<0.01). When the dF/starch ratio was 1.44, the pellets had the lowest powder and highest durability. The dF/starch ratio had unfavorable linear effects on growth variables (p<0.001). When analyzed by quadratic regression, the optimal dF/starch ratios for average weight gain and feed/gain were 0.59 and 0.74, respectively. There were differences in wool yield, fiber length and fiber diameter caused by the dF/starch ratio (p<0.05), and the dF/starch ratios that ranged from 0.66 to 1.06 were appropriate for good results. The cecal microbiota operational taxonomic unit (OTU) number index in the 1.05 dF/starch treatment was higher than that in the 0.66 and 0.71 dF/starch treatments. The higher dF/starch ratio resulted in a higher cecal microbiota OTU number index (p<0.05). The proportion of Ruminococcus in the 0.71 dF/starch treatment was higher than that in the 0.59 dF/starch treatment (p<0.05) Conclusion: The most suitable dF/starch ratio for feed pellet quality is 1.44, and for rabbit growth the optimal range of ratios is from 0.59 to 0.74. With combination of the wool growth, output cost, and cecal microbiota, we suggest that a dietary dF/starch ratio ranging from 0.74 to 1.06 is optimal.

• 통상정보연구
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• 제7권4호
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• pp.387-407
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• 2005

This paper is to study globalization motives and strategies of Japanese and Korean industries by analyzing the causes and patterns of foreign direct investment (FDI) of the firms of the two countries during the 1980s and 1990s. First we develop a FDI function from the profit maximizing model of firms. Then we use regression analysis to determine internally driving-out factors and externally-inducing factors. Japanese FDI strategy has gone through three different stages; from natural resource-seeking investment in the 1950s and 1960s to market-expansion investment in the 1970s and 1980s and to a combination of cost-reducing (low-cost labor-seeking) investment and market-penetrating investment in the 1990s. On the other hand, Korean FDI behavior has gone through four different stages; from the learning stage with small investments in the 1970s, to natural resource-seeking investment in the early and mid 1980s, to the growth stage in the late 1980s and the early 1990s, to the maturity stage of the mid and late 1990s. The last two stages were characterized by a combination of cost-reducing investment and market-seeking investment. As a late comer, Korea began its FDI two decades later than Japan, but caught up the patterns of Japanese FDI by the mid 1990s and is in a competing position with Japan. Our findings show that both Japanese FDI and Korean FDI in Asia and other developing countries tendto be in labor-intensive sectors where their firms are losing their comparative advantages at home. The main motive for FDI into these regions is low-cost resource seeking. On the other hand, both Japanese FDI and Korean FDI in the U.S. and Europe tend to be knowledge-intensive sectors where Japanese and Korean firms attempt to internalize transaction and information costs by globalizing its production. The main motive for FDI into these regions is market-seeking. Firms in both countries have increased their investments in Mexico and Western and Eastern Europe in order to penetrate large economic blocs such as the EU and NAFTA area. Korean firms are more aggressive in expanding into new and untested markets than are their counterpart in Japan. Evidence of this can be seen in the scarcity of Japanese FDI and abundance of Korean FDI in Eastern Europe and China.