• International Journal of Advanced Culture Technology
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• 제8권2호
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• pp.252-259
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• 2020

Wheatgrass is a type of young grass that contains a lot of vitamins, minerals, and protein even compared to grain products produced from its mature cereal plants. In the context of product development and increasing product sales value, a study on the use of wheatgrass extract as an ingredient of fermented beverage was conducted. In this study wheatgrass used was self-grown using a tray in the Laboratory. The variation of wheatgrass extracts used was obtained from the twin-gear type extractor, slow-squeeze type extractor, and chopped wheatgrass. In the extraction process, the performances of the process: density, extract yield, processing capacity, and the rate of production, were analyzed. For another analysis, the physicochemical properties both of wheatgrass extracts and fermented beverages were also analyzed. The physicochemical properties analyzed included TSS, pH, acidity, and others content. The results of extraction performance analysis and physicochemical characteristics of wheatgrass extract planted at 10-20℃ based on this research gave the best results using the twin-gear extractor. The twin-gear type of extractor used in this study. All of these results were also in accordance with the statistical analysis conducted in this study.

• 한국수정란이식학회지
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• 제15권3호
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• pp.255-261
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• 2000

The objective of this study was to improve the efficiency of bovine embryo transfer by transferring of Hanwoo embryos into Hanwoo or Holstein recipients. The cryopreserved or fresh in vitro produced(IVP) embryos were transferred into uterine horn contralaterally or ipsilaterally to the corpus luteum. The recipients were inseminated by artificially on the next day of estrus. The pregnancy was diagnosed by rectal palpation at 60∼90 days after transfer of the embryos. The pregnancy rate by transfer of one or two embryos was 78%(7/9) and 74%(31/42), respectively. The pregnancy rates according to the grade of corpus lutea of recipients was 75% (20/27) and 82.0%(18/22) at the grade of A and B, respectively. Ten(67.0%) of 15 Holstein recipients transferred with IVP Hanwoo embryos and 5(42.0%) of 12 Holstein recipients transferred with frozen IVP Hanwoo embryos were pregnant. The single and twin calving ratio in Hanwoos was 77.0%(10/13) and 23.0%(3.13) in the recipients transferred with IVP embryos and 64.0%(7/10) and 27.0%(3/10) in the recipients transferred with frozen IVP embryos, respectively. Twenty-four pregnant cows following transfer of IVP embryos, 21(88.0%) calved the normal calves, and 2(8.3%) aborted. When the frozen IVP embryos were transferred, 16 pregnant cows calved 14(88.0%) normal calves and 2(13.0%) aborted. In conclusion, when one or two IVP bovine embryos were transferred into recipients, the A and B grade of corpus luteum resulted in high pregnancy rates. For the production of twin calves, transfer of the IVP or frozen IVP embryos could be suitable.

• 한국정보전자통신기술학회논문지
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• 제12권6호
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• pp.537-546
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• 2019

본 논문에서는 휴대하기 편하고 3D 콘텐츠 제작이 용이한 트윈 카메라 모듈 시스템을 구현하고자 하였다. 제안한 트윈 카메라 모듈 시스템은 2D 스테레오 카메라로 부터 입력되는 영상을 변환하여 3차원 영상으로 출력할 수 있는 시스템이다. 본 눈문에서 제안한 시스템의 성능평가를 위해 Test Platform을 이용하여 좌, 우 두 개의 렌즈로 촬영된 스테레오 입체 영상의 좌, 우 영상 간의 시차에 따른 회전(Rotation), 기울기(Tilt)에 대한 보정을 평가하였다. 또한 SIFT(Scale Invariant Feature Transform) 알고리즘을 이용하여 3D 입체 영상의 거리오차(Depth Error)를 검증하여 트윈 카메라 모듈 시스템의 효율성을 검증하고자 하였다. 본 논문에서 제안한 트윈 카메라 모듈 시스템은 촬영된 영상을 3D 입체 영상과 준비 영상으로 변화하여 외부에 출력하면 각기 다른 3D 입체 영상 제작 방식에 따른 출력장치에 맞춰 디스플레이가 가능하다. 또한 생성된 영상을 준비 영상과 입체 영상을 각기 다른 채널을 통해 출력하여 많은 제품에 적용하기 쉽고 간편하게 3D 입체 영상 콘텐츠를 제작하는데 이용할 수 있을 거라 기대한다.

• 한국융합학회논문지
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• 제9권9호
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• pp.199-207
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• 2018

본 연구는 4차 산업혁명으로 불리는 생산 패러다임 변화에 선도적으로 대응하기 위해 차세대 생산혁신 기술을 증거기반 키워드 네트워크를 통해 분석하는 것을 목적으로 한다. 분석을 위해 차세대 생산혁신 기술과 관련한 총 441건의 논문데이터를 추출하였고, 이 논문들의 저자 키워드 동시 등장 관계를 기반으로 차세대 생산혁신 기술 네트워크를 구축하였다. 구축된 기술 네트워크를 바탕으로 중심성 및 키워드 그룹 분석을 통해 주요 기술을 탐색하였다. 그 결과 'digital twin', 'modeling and simulation' 등 가상세계와 물리세계를 실시간으로 완벽하게 연결하여 인사이트를 발견하고, 이를 설계 및 공정에 반영하는 기술들이 주요 기술로 분석되었다. 이러한 결과는 관련 산업 내에서 4차 산업혁명으로 인한 변화를 대비하는 기업들에게 의미 있는 정보를 줄 수 있을 것으로 기대된다.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2007년도 춘계학술대회 논문집
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• pp.364-367
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• 2007

Typical seamless tube production methods are an extrusion and a rotary tube piercing. The rotary piercing process is more competitive than the extrusion process form view point of productivity, quality, and flexibility. It consists of twin rolling mills, a pair of disc or flat guides, and a plug. Twin rolling mills are skewed with proper angles in two directions. A round billet is progressively fed forward and rotated due to the rotation of twin rolling mills. Internal crack initiation and growth at central area of the billet are gradually progress because of the repeating actions of tension and rotation. Design variables in the rotary piercing rolling process are the feed angle, the cross angle, the reduction ratio, and the position of plug. In this work, a rotary tube piercing machine was developed and parametric studies on design variables were carried out using finite element analysis. The Brozzo ductile fracture criterion was utilized to determine an internal crack initiation.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2008년도 추계학술대회 논문집
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• pp.313-316
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• 2008

This work sought to examine the suitability of twin roll strip casting for Ag-27%Cu-25%Zn-3%Sn brazing alloy (BAg-7A) and to investigate the mechanical properties and microstructure of the strip. The effect of aging heat treatment on the properties was also studied,. This new manufacturing process has applications in the production of the brazing alloy. XRD and microstructural analysis of the Ag-27%Cu-25%Zn-3%Sn strip represented eutectic microstructure of a Cu-rich phase and a Ag-rich matrix regardless of heat treatment. The results of mechanical tests showed tensile strength of 470MPa, a significant enhancement, and an 18% elongation of the twin roll casted strip, due mainly to the solid solution strengthening of Zn atoms (${\sim}20%$) in the Cu-rich phases. Tensile results showed gradually decreasing strengths and increasing elongation with aging heat treatment. Microstructural evolution and fractography were also investigated and related to the mechanical properties.

• Korea-Australia Rheology Journal
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• 제20권4호
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• pp.235-243
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• 2008

The aim of this study is to explore the possibility of incorporating supercritical carbon dioxide ($scCO_2$) into twin screw extrusion process for the production of polypropylene-clay nanocomposite (PPCN). The $CO_2$ is used as a reversible plasticizer which is expected to rapidly transport polymeric chains into the galleries of clay layers in its supercritical condition inside the extruder barrel and to expand the gallery spacings in its sub-critical state upon emerging from die. The structure and properties of the resulting PPCNs are characterized using wide-angle X-ray diffraction (WAXD), transmission electron microscopy (TEM), rheometry, thermogravimetry and mechanical testing. In the processing of the PPCNs with $scCO_2$, optimum $scCO_2$ concentration and screw speed which maximized the degree of intercalation of clay layers were observed. The WAXD result reveals that the PP/PP-g-MA/clay system treated with $scCO_2$ has more exfoliated structure than that without $scCO_2$ treatment, which is supported by TEM result. $scCO_2$ processing enhanced the thermal stability of PPCN hybrids. From the measurement of linear viscoelastic property, a solid-like behavior at low frequency was observed for the PPCNs with high concentration of PP-g-MA. The use of $scCO_2$ generally increased Young's modulus and tensile strength of PPCN hybrids.

• 한국기계가공학회지
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• 제11권6호
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• pp.152-157
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• 2012

This study investigates compressive strength of ice pellet strip which is potential medium for Natural Gas Hydrate(NGH) extruded from die holes of Twin-roll Press for Continuous Pelletizing(TPCP). Recently, the prototype of TPCP is newly developed where ice powder is continuously fed and extruded into strip-type pellet between twin rolls. The system is specifically designed for future expansion towards mass-production of ice pellet strips or solid form of natural gas hydrate. It is shown that the compressive strength of pellet strip heavily depends on factors in extrusion process such as disk size, surface smoothness, ring size, taper shape, feeding mechanism, and rotational speed. Here, the mechanism of TPCP, along with compressive strength of pellets is discussed in terms of its feasibility for producing NGH pellets in the future.

• International Journal of Internet, Broadcasting and Communication
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• 제16권1호
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• pp.269-279
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• 2024

The study explores the evolving landscape of overseas expansion strategies by Korean corporations, focusing on recent geopolitical tensions, the COVID-19 pandemic, and disruptions in global supply chains. It emphasizes the challenges faced by industries producing high-value products and delves into the concept of "Friend-Shoring" policies in the United States, leading major Korean companies to invest in local semiconductor, battery, and automotive factories. Recognizing the potential fragmentation of Korea's manufacturing sector, the paper introduces the "Mother Factory" strategy as a policy initiative, inspired by Japan's model, to establish core production facilities domestically. The discussion unfolds by examining the cases of major companies in Japan and the United States, highlighting the need for Korea to adopt a mother factory strategy to mitigate risks associated with friend-shoring policies. Inspired by Intel's "Copy Exactly" approach, the paper proposes a Korean mother factory model integrating smart factory technology and digital twin systems. This strategic shift aims to enhance responsiveness to geopolitical challenges and fortify the competitiveness of Korean high-tech industries. Finally, the paper proposes a Korean Mother Factory based on smart factory concepts. The suggested model integrates smart factory technology and digital twin frameworks to enhance responsiveness and fortify competitiveness. In conclusion, the paper advocates for the adoption of a comprehensive Korean Mother Factory model to address contemporary challenges, foster advanced manufacturing, and ensure the sustainability and competitiveness of Korean high-tech industries in the global landscape. The proposed strategy aligns with the evolving dynamics of the manufacturing sector and emphasizes technological advancements, collaboration, and strategic realignment.

• Asian-Australasian Journal of Animal Sciences
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• 제30권9호
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• pp.1270-1277
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• 2017

Objective: The present study aimed to determine the impact of ewe body condition score (BCS) (over a range of 2.0 to 3.0) and nutritional treatments (consisting of differing herbage masses) during very late pregnancy and lactation and their potential interaction on the performance of twin-bearing ewes and their lambs to weaning. Methods: On day 142 of pregnancy, twin-bearing ewes with a BCS of 2.0, 2.5, or 3.0 were allocated to a "Moderate' or 'Unrestricted' nutritional treatment until day 95 of lactation (weaning). The nutritional treatments aimed to achieve average herbage masses of 1,200 to 1,300 kg dry matter (DM)/ha (Moderate) and 1,500 to 1,800 kg DM/ha (Unrestricted). Results: There were no three-way interactions between ewe BCS group, nutritional treatment and time for any ewe or lamb parameter. The nutritional treatments had no effect (p>0.05) on lamb birth or weaning weight. Lambs born to Moderate ewes had greater survival and total litter weight at weaning (p<0.05). Regardless of BCS group, Unrestricted treatment ewes had greater body condition and back-fat depth at weaning than Moderate treatment ewes (p<0.05). Ewes of BCS 2.0 group reared lighter lambs to weaning (p<0.05) and tended to have a lower total litter weight (p = 0.06) than BCS 3.0 group ewes. Conclusion: This study suggests farmers should aim to have all ewes with a BCS of 2.5 or 3 in late pregnancy for optimal lamb weaning performance. Furthermore, there is no benefit to lamb production of offering ewes pasture masses >1,200 kg DM/ha during very late pregnancy and lactation.