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        검색결과 76

        1.
        2021.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Ni–Cr–Al metal-foam-supported catalysts for steam methane reforming (SMR) are manufactured by applying a catalytic Ni/Al2O3 sol–gel coating to powder alloyed metallic foam. The structure, microstructure, mechanical stability, and hydrogen yield efficiency of the obtained catalysts are evaluated. The structural and microstructural characteristics show that the catalyst is well coated on the open-pore Ni–Cr–Al foam without cracks or spallation. The measured compressive yield strengths are 2–3 MPa at room temperature and 1.5–2.2 MPa at 750oC regardless of sample size. The specimens exhibit a weight loss of up to 9–10% at elevated temperature owing to the spallation of the Ni/Al2O3 catalyst. However, the metal-foam-supported catalyst appears to have higher mechanical stability than ceramic pellet catalysts. In SMR simulations tests, a methane conversion ratio of up to 96% is obtained with a high hydrogen yield efficiency of 82%.
        4,000원
        2.
        2021.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In the winter forage study, Italian ryegrass(IRG) and barley were selected. In 2018, the dry matter yield of IRG was 16,915kg per ha under the Agrivoltaic System; this was a little more than 16,750kg per ha of outdoors. On the contrary, the dry matter yield of barley was slightly less under the Agrivoltaic System than that of outdoors. In 2019, the dry matter yield under the Agrivoltaic System was 12,062kg per ha for IRG and 12,195kg per ha for the barley; this was 5.4% and 11.5% less than that of outdoors, respectively. In the summer forage study, corn and sorghum×sudangrass were selected. In 2019, the dry matter yield of corn under the Agrivoltaic System was 13,133kg per ha which was 17% less than that of outdoors. The dry matter yield of sorghum×sudangrass was 12,450kg per ha, which was 82.5% of that of outdoors. In 2020, the dry matter yield of corn under the Agrivoltaic System was 8,033kg per ha which was 7.9% less than that of outdoors. The dry matter yield of sorghum×sudangrass was 5,651kg per ha, which was 11.4% less than that of outdoors.
        4,000원
        4.
        2020.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to develop a technique for the stable production of Italian ryegrass(IRG) seeds in reclamation sites. Harvesting 35 days after heading in Autumn resulted in the highest production, an average of 2,232kg/ha. The production yield decreased due to seed loss as harvesting was delayed to 45 and 55 days post-heading. For the harvested 35 days post-heading, under growing rice sowing resulted in 80% seed yield of after rice sowing's; spring sowing resulted in 40%. After rice sowing using the domestic IRG seeds of 30kg/ha produced the highest seed yield of 2,507kg/ha. The highest straw yield has resulted when using the imported IRG seeds of 20kg/ha for after rice sowing 35 days post-heading fresh weight 36,667kg/ha, dry weight 14,500kg/ha, and TDN weight 7,895kg/ha.
        4,000원
        6.
        2020.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The Fe-22wt.%Cr-6wt.%Al foams were fabricated via the powder alloying process in this study. The structural characteristics, microstructure, and mechanical properties of Fe-Cr-Al foams with different average pore sizes were investigated. Result of the structural analysis shows that the average pore sizes were measured as 474 μm (450 foam) and 1220 μm (1200 foam). Regardless of the pore size, Fe-Cr-Al foams had a Weaire-Phelan bubble structure, and α-ferrite was the major constituent phase. Tensile and compressive tests were conducted with an initial strain rate of 10−3 /s. Tensile yield strengths were 3.4 MPa (450 foam) and 1.4 MPa (1200 foam). Note that the total elongation of 1200 foam was higher than that of 450 foam. Furthermore, their compressive yield strengths were 2.5 MPa (450 foam) and 1.1 MPa (1200 foam), respectively. Different compressive deformation behaviors according to the pore sizes of the Fe-Cr-Al foams were characterized: strain hardening for the 450 foam and constant flow stress after a slight stress drop for the 1200 foam. The effect of structural characteristics on the mechanical properties was also discussed.
        4,000원
        7.
        2019.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted to establish spring sowing techniques in preparation for the impacts of climate change on sowing time and wintering rates of winter forage crops such as barley, oat and IRG. Oat showed the highest yield in 2017 which had relatively dry climate condition. And when sowing in late Febrnary 2017 yielding 9,408kg/ha were obtained, yielding 4,011kg/ha more than IRG's sown in the same period. In 2018 which had relatively wet climate condition, four barley species decreased in the production from the previous year. Oat also had decreased by 70% from 9,408kg/ha to 2,851kg/ha. On the other hand, IRG maintained the production in the mid-5,000kg/ha range. It was also found that IRG had the least variability due to external influences regardless of seeding period for 2 years. Mixed sowing with IRG and oat in 50:50 ratio was the highest dry matter, 6,584kg/ha, and IRG was 18.5% and Oat was 2.3 times higher than single planting.
        4,000원
        10.
        2018.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Porous metals demonstrate not only excessively low densities, but also novel physical, thermal, mechanical, electrical, and acoustic properties. Thus, porous metals exhibit exceptional performance, which are useful for diesel particulate filters, heat exchangers, and noise absorbers. In this study, SUS316L foam with 90% porosity and 3,000 μm pore size is successfully manufactured using the electrostatic powder coating (ESPC) process. The mean size of SUS316L powders is approximately 12.33 μm. The pore properties are evaluated using SEM and Archimedes. As the quantity of powder coating increases, pore size decreases from 2,881 to 1,356 μm. Moreover, the strut thickness and apparent density increase from 423.7 to 898.3 μm and from 0.278 to 0.840 g/cm3, respectively. It demonstrates that pore properties of SUS316L powder porous metal are controllable by template type and quantity of powder coating.
        4,000원
        11.
        2018.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was conducted in 2014 in the Gangjin area of Jeonnam province for the purpose of confirming the potential of Kenaf as an alternative feed crop of rice. The weather and soil conditions were favorable and there was no adverse effect on the growth of Kenaf. The amount of seeding was given at 10 kg, 15 kg and 20 kg. As the seeding volume increased, plant height and dry matter yield increased, and stem diameter and number of nodes decreased. The highest growth rate was observed between 75 and 90 days from the date of planting(p<0.05). As the growth progressed, stem rate increased and leaf rate decreased(p<0.05). Increased amount of seeding and growth resulted in decreased CP and TDN and increased ADF and NDF, which resulted in the decreased economic value of Kenaf as a feed crop. The result of increasing the use of organic fertilizer to 20 kg and 30 kg was similar to increasing the amount of seeding. As organic fertilizer usage increased, dry matter yield and growth rate improved(p<0.05).
        4,000원
        12.
        2018.06 구독 인증기관 무료, 개인회원 유료
        급격한 의학과 과학의 발달로 우리사회는 고령화 사회로 접어들었다. 통계청이 발표한 2015년도 고령자 통계에 따르면 우리나라의 65세 이상인구는 총 657만 명으로 전체인구에서 차지하는 비중이 13%를 넘어섰다. 전체 인구에서 고령자가 차지하는 비율은 2000년 7.3%, 2005년 9.3%, 2010년 11.3%, 2015년 13.2%로 계속 높아지고 있으며 2017년 8월말 현재 우리나라 65세 이상 인구는 총 726만 명으로 전체 인구에서 차지하는 비중이 13.8%로 고령사회로 들어섰다고 발표하였다. 그것은 고령화가 급속도로 진행되고 있음을 보여준다. 그로 인해 고령자 인구 증가와 함께 눈여겨보아야 할 부분은 삶의 질과 죽음의 질을 살펴 볼 필요가 있다. 경제협력개발기구(OECD)에서 발표한 우리나라는 2017년도 ‘삶의 질(Better Life Index)‘지수가 회원국 38개국 중 29위로 머물러 있고, 2013년도 영국 경제 주간 이코노미스트 산하기관인(EIU)에서 ‘죽음의 질 지수(Quality of Death Index)’ 또한 40개국 중에서 32번째라고 밝혔다. 인간은 태어나고 자라고 늙어서 죽는다. 그러므로 노년기 진입을 앞두고 있는 중장년층에 대한 이론적 탐색과 죽음의 태도, 자아 통합감, 사회적 자본을 분석하기 위한 이론적 근거를 제시하고자 한다.
        4,900원
        13.
        2016.08 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In this study, the recently developed Al 2013 alloy was T8-tempered and, to improve the strength and corrosionresistance, slight amounts of Zr of 0.2 wt% and 0.5 wt%, respectively, were added and the mechanical properties were analyzed. For microstructure and precipitate analysis, OM observation, XRD analysis, and TEM analysis were performed, and for the mechanical property analysis, hardness and tensile strength tests were done. Also, in order to determine the corrosion rate according to the Zr content, a potentiodynamic polarization test was performed and the properties were compared and analyzed. The size of the precipitate varied with the content of Zr and was finest at Zr content of 0.2 wt%; it grew larger at 0.5 wt%, at which point the hardness value accordingly showed the same trend. On the other hand, as calculated from the aspect of chemical bonding among atoms, it was confirmed that the tensile strength and the corrosion-resistance increased with the same trend.
        4,000원
        14.
        2016.07 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Flower-like nickel oxide (NiO) catalysts were coated on NiCrAl alloy foam using a hydrothermal method. The structural, morphological, and chemical bonding properties of the NiO catalysts coated on the NiCrAl alloy foam were investigated by field-emission scanning electron microscopy, scanning electron microscopy-energy dispersive spectroscopy, Xray diffraction, and X-ray photoelectron spectroscopy, respectively. To obtain flower-like morphology of NiO catalysts on the NiCrAl alloy foam, we prepared three different levels of pH of the hydrothermal solution: pH-7.0, pH-10.0, and pH-11.5. The NiO morphology of the pH-7.0 and pH-10.0 samples exhibited a large size plate owing to the slow reaction of the hydroxide (OH−) and nickel ions (Ni+) in lower pH than pH-11.5. Flower-like NiO catalysts (~4.7 μm-6.6 μm) were formed owing to the fast reaction of OH− and Ni2+ by increased OH− concentration at high pH. Thus, the flower-like morphology of NiO catalysts on NiCrAl alloy foam depends strongly on the pH of the hydrothermal solution.
        4,000원
        15.
        2015.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In this study, Analyzed the Battlefield4(FPS Game) through the 12 phases of Hero’s Journey, which was suggested by Christopher Vogler. Through this, we confirmed the potential of narrative in FPS game. Based on the results, This study analyzed how utilizes the narrative in Battlefield4 game. First, the narrative has been extend through trans-media storytelling. Second, campaign experience and multi-play experience play are overlapped. Third, the profit(Dogtag, Badge, Equipment etc.) obtained in the course of an narrative game experience(Campaign) can be used in the multi-play environment. As a result, we confirmed the narrative possibilities of the FPS game genre. And the game narrative of campaign is extended as to multi-play experience. It would be able to suggest a new development direction in the Korea online FPS games of the multi-play environment.
        4,000원
        18.
        2015.08 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        NiO catalysts/Al2O3/FeCrAl alloy foam for hydrogen production was prepared using atomic layer deposition (ALD)and subsequent dip-coating methods. FeCrAl alloy foam and Al2O3 inter-layer were used as catalyst supports. To improve thedispersion and stability of NiO catalysts, an Al2O3 inter-layer was introduced and their thickness was systematically controlledto 0, 20, 50 and 80nm using an ALD technique. The structural, chemical bonding and morphological properties (includingdispersion) of the NiO catalysts/Al2O3/FeCrAl alloy foam were characterized by X-ray diffraction, X-ray photoelectronspectroscopy, field-emission scanning electron microscopy and scanning electron microscopy-energy dispersive spectroscopy. Inparticular, to evaluate the stability of the NiO catalysts grown on Al2O3/FeCrAl alloy foam, chronoamperometry tests wereperformed and then the ingredient amounts of electrolytes were analyzed via inductively coupled plasma spectrometer. We foundthat the introduction of Al2O3 inter-layer improved the dispersion and stability of the NiO catalysts on the supports. Thus, whenan Al2O3 inter-layer with a 80nm thickness was grown between the FeCrAl alloy foam and the NiO catalysts, it indicatedimproved dispersion and stability of the NiO catalysts compared to the other samples. The performance improvement can beexplained by optimum thickness of Al2O3 inter-layer resulting from the role of a passivation layer.
        4,000원
        20.
        2015.05 KCI 등재 구독 인증기관 무료, 개인회원 유료
        국가차원의 슈퍼컴퓨팅 성능수요 예측은 슈퍼컴퓨터를 활용하는 계산과학분야 의 연구자나 연구개발 인프라를 구축⋅운영하고 있는 전문기관, 과학기술 인프라구축을 주도 할 정부기관에 있어서 매우 중요한 정보이다. 본 연구는 그동안 진행되었던 슈퍼컴퓨터 성능관련 예측활동 분석을 통해 과학기술 역량 에 영향을 미치는 요인들을 도출하고 이를 슈퍼컴퓨터 기술진보 추세에 적용한 복합 예측모 형을 제안하였다. 횡단면분석에서는 슈퍼컴퓨팅 성능에 영향을 미칠 것으로 판단되는 GDP, GERD, 연구원수, SCI논문수를 고려한 다중회귀분석을 수행하였다. 그리고 횡단면분석 결과 에 Top500 자료의 성능(Rmax)값을 이용한 시계열분석을 통해 도출된 기간별 기술진보율을 곱하여 슈퍼컴퓨터의 성능을 예측하였다. 제안된 예측모형을 바탕으로 세계 슈퍼컴퓨터 500위의 시계열자료를 이용하여 한국이 2016년에 보유해야 할 슈퍼컴퓨터 성능규모를 예측하였다. 횡단면분석과 기술진보율을 적 용하여 2016년 한국의 슈퍼컴퓨팅 성능수요를 예측해본 결과 현재의 추세를 이용할 경우 15~30PF 정도, 목표 국가수준의 추세를 이용할 때 20~40PF 정도의 컴퓨팅 역량이 필요할 것으로 예측되었다. 이 결과는 단순 회귀분석을 적용한 결과인 9.6PF와 횡단면분석을 적용 한 결과인 2.5PF와 큰 차이를 나타내었다.
        5,800원
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