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        검색결과 30

        2.
        2023.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 광질이 장미의 꽃잎 착색에 미치는 영향에 대한 기초자료를 얻고자 수행했다. 꽃눈 분화가 시작된 미니 장미 5품종 ‘Berigamo’(yellowish white), ‘Elpaso Yellow’(yellow), ‘Elpaso’ (bicolor, yellow+orange), ‘Meggiore’(pink), ‘Maasland’(red)를 대상으로 3주간 광질처리를 실시하였다. 광질처리는 300μmol·m-2·s-1 백 색광(W) 대조구와 210μmol·m-2·s-1 백색광에 적색(R), 녹색(G), 청색(B), 원적외선(FR) 및 자외선 B(UVB)을 각 90μmol·m-2·s-1 보광하여 대조구와 동일한 PPFD로 설정하였다. 광질의 꽃잎착색 효과는 품종 특이적으로 R, FR, UVB 보광은 특히 분홍색 품종에서 각각 19.0%, 28.8%, 6.4% 착색을 증진시킨 반면, G와 B 보광은 안토시아닌 함량을 각각 17.8%, 19.0% 감소시켰 다. 황색 품종에서는 UVB보광으로 카로티노이드 함량이 19.6% 증가하였다.
        4,000원
        3.
        2022.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In the powder bed fusion (PBF) process, a 3D shape is formed by the continuous stacking of very fine powder layers using computer-aided design (CAD) modeling data, following which laser irradiation can be used to fuse the layers forming the desired product. In this method, the main process parameters for manufacturing the desired 3D products are laser power, laser speed, powder form, powder size, laminated thickness, and laser diameter. Stainless steel (STS) 316L exhibits excellent strength at high temperatures, and is also corrosion resistant. Due to this, it is widely used in various additive manufacturing processes, and in the production of corrosion-resistant components with complicated shapes. In this study, rectangular specimens have been manufactured using STS 316L powder via the PBF process. Further, the effect of heat treatment at 800 °C on the microstructure and hardness has been investigated.
        4,000원
        5.
        2019.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Pb(Zr,Ti)O3 (PZT) is used for the various piezoelectric devices owing to its high piezoelectric properties. However, lead (Pb), which is contained in PZT, causes various environment contaminations. (K,Na)NbO3 (NKN) is the most well-known candidate for a lead-free composition to replace PZT. A single crystal has excellent piezoelectric-properties and its properties can be changed by changing the orientation direction. It is hard to fabricate a NKN single crystal due to the sodium and potassium. Thus, (Na,K)NbO3-Ba(Cu,Nb)O3 (NKN-BCuN) is chosen to fabricate the single crystal with relative ease. NKNBCuN pellets consist of two parts, yellow single crystals and gray poly-crystals that contain copper. The area that has a large amount of copper particles may melt at low temperature but not the other areas. The liquid phase may be responsible for the abnormal grain growth in NKN-BCuN ceramics. The dielectric constant and tan δ are measured to be 684 and 0.036 at 1 kHz in NKN-BCuN, respectively. The coercive field and remnant polarization are 14 kV/cm and 20 μC/cm2.
        4,000원
        6.
        2019.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Lead free (Ba0.7Ca0.3) TiO3 thick films with nano-sized grains are prepared using an aerosol deposition (AD) method at room temperature. The crystallinity of the AD thick films is enhanced by a post annealing process. Contrary to the sharp phase transition of bulk ceramics that has been reported, AD films show broad phase transition behaviors due to the nanosized grains. The polarization-electric hysteresis loop of annealed AD film shows ferroelectric behaviors. With an increase in annealing temperature, the saturation polarization increases because of an increase in crystallinity. However, the remnant polarization and cohesive field are not affected by the annealing temperature. BCT AD thick films annealed at 700 ℃/2h have an energy density of 1.84 J/cm3 and a charge-discharge efficiency of 69.9%, which is much higher than those of bulk ceramic with the same composition. The higher energy storage properties are likely due to the increase in the breakdown field from a large number of grain boundaries of nano-sized grains.
        4,000원
        7.
        2016.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        상업용 부동산에 대한 관심에 비해 투자자가 활용할 수 있는 유용한 정보가 부족하다. 본 연구는 투자정보로서 층별 효용비율의 활용 가능성을 확인하고자 한다. 층별 효용비율은 건물의 수직적 이용에 따라 나타날 수 있는 효용의 상대적인 차이를 수치화한 것으로 상업용 부동산은 1층의 임대료나 가격 대비 비교 층 값의 비율로 표현한다. 이와 관련한 상업용 부동산에 대한 기존 연구는 대부분 임대료 산정에 초점을 두어 가격 변동 여력 등 다양한 투자정보로 활용하기 어려운 한계가 있다. 본 연구는 상권 특성 분석과 동향 탐색을 위하여 임대료 층별 효용비율뿐만 아니라 자산가치 및 투자수익률의 층별 효용비율을 활용한다. 분석결과 제시된 층별 효용비를 개별적 또는 통합하여 비교 분석함으로써 상권 활성도, 업무 및 매장 중심 여부 등 상권의 특성 파악과 향후 변동 추이를 효율적으로 예측할 수 있는 도구로 이용할 수 있을 것으로 파악되었다.
        4,000원
        8.
        2016.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was carried out to assess the carbon budget of two urban parks and one natural park and to prepare the plan for improving the ecological functions of the park including carbon sink. Net Ecosystem Production (NEP) of those study sites was calculated from the relationship between Net Primary Production (NPP) and soil respiration of each study site. To understand carbon budget of the whole area designated as the park, carbon budget of the urban park was analyzed by classifying the vegetated and the non-vegetated zones. NEP of the Nohae and the Sanggye parks calculated by reflecting areal size that the non-vegetated zones occupy were shown in - 1.0 and 0.6 ton C ha-1 yr-1, respectively. On the other hand, NEP of Mt. Bulam natural park as a reference site was in 2.3 ton C ha-1 yr-1. Based on the result, the Nohae park was assessed as carbon source rather than carbon sink. On the other hand, the Sanggye park was classified as carbon sink but the role was poor compared with natural park. The result is, first of all, due to lower NPP of the vegetation introduced for the parks compared with natural vegetation. The other reason is due to wide arrangement of non-vegetated zone. To solve those problems and thereby to create the urban park with high ecological quality, selection of plant species suitable for the ecological characteristic of the park, their arrangement imitated natural vegetation, and ecological zoning were recommended.
        4,200원
        10.
        2012.01 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Research into the development of high strength (1 GPa) and superior formability, such as total elongation (10%), and stretch-flangeability (50%) in hot-rolled steel was conducted with a thermomechanically controlled hot-rolling process. To improve the overall mechanical properties simultaneously, low-carbon steel using precipitation hardening of Ti-Nb-V multimicroalloying elements was employed. And, ideal microstructural characteristics for the realization of balanced mechanical properties were determined using SEM, EBSD, and TEM analyses. The developed steel, 0.06C-2.0Mn-0.5Cr-0.2(Ti + Nb + V), consisted of ferrite as the matrix phase and second phase of granular bainite with fine carbides (20-50 nm) in both phases. The significant factor of the microstructural characteristics that affect stretch-flangeability was found to be the microstructural homogeneity. The microstructural homogeneity, manifest in such characteristics as low localization of plastic strain and internally stored energy, was identified by grain average misorientation method, analyzed by electron backscattered diffraction (EBSD) and hardness deviation between the phases. In summar, a hot-rolled steel having a composition 0.06C-2.0Mn-0.5Cr-0.2(Ti + Nb + V) demonstrated a tensile strength of 998 MPa, a total elongation of 19%, and a hole expansion ratio of 65%. The most important factors to satisfy the mechanical property were the presence of fine carbides and the microstructural homogeneity, which provided low hardness deviation between the phases.
        4,000원
        11.
        2011.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Environment standards can be used as a foundation of environment administration (specific expression of political goals or quantitative evaluation standards of political effects). When environment adminstration improves severe air or water pollution rapidly, the environment standard can work effectively to show the goals specifically and clearly. The environment index which is designed to evaluate environment systems, should be established to express the environment system generally. To realize sustainable development, the sustainable indexes usually consisting of these three areas in that harmony of environment, economy and society are required. In this research, sustainable environmental indicators to understand the characteristics and to compare likes theme of environmental conditions in international and national level indicators, regional environmental management plan to promote the management by objectives are to provide the basic data. It is desirable for the environmental policies to work harmoniously with direct control, use of economic means and voluntary methods. Regarding the evaluation of environmental index, the action results of civilian's or individual's activities are needed to be reflected into the evaluation.
        4,000원
        12.
        2011.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        A core device of foam system is the in-line eductor and it is the device to mix the foam liquid into liquid solution proper to the use density and the mixture ratio must be kept regularly regardless of changing fluid condition of the front and rear end of the in-line eductor. However, if the flux of the pressurized water changes, the mixture ratio is not kept regularly, and so it becomes a cause which a performance of fire-extinguishing deteriorates in discharging foam liquid. I devise a method to improve it that the metering orifice type in-line eductor is improved into the metering venturi type in-line eductor, the fluctuation of the mixture ratio to the flux change of the pressurized water is minimized and the performance of fire-extinguishing is kept regularly. As this method is simple in its structure and can be designed at a low cost, it helps for maintenance as well. In the future, it seems to need the research for the metering nozzle type in-line eductor in the future.
        4,000원
        13.
        2009.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 우리나라 기업의 구성원이 지각하는 조직문화 가치변수 변화 추세와 조직성과의 관계에 관해 살펴본다. 이를 위하여 본 연구는 한국의 상장기업 240개 표본을 대상으로 실증분석을 하였다. 연구결과, 먼저 시간적 흐름(IMF 이전과 현재시점)에 따라 구성원이 지각하는 각 조직문화 가치 변수의 평균치는 “구성원 노동력의 중요성”에 관한 조직문화 가치 변수를 제외한 나머지 조직문화 가치 변수의 평균치는 변화된 것으로 분석 되었다. 세부적으로 우리나라 기
        5,700원
        14.
        2009.02 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        This study investigated the dependence of the various sputtering conditions (Ar pressure: 2~10 mTorr, Power: 50~150 W) and thickness (50~1200 nm) of Si thin film on the electrochemical properties, microstructural properties and the capacity fading of a Si thin film anode. A Si layer and a Ti buffer layer were deposited on Copper foil by RF-magnetron sputtering. At 10 mTorr, the 50 W sample showed the best capacity of 3323 mAh/g, while the 100 W sample showed the best capacity retention of 91.7%, also at 10 mTorr. The initial capacities and capacity retention in the samples apart from the 50W sample at 10 mTorr were enhanced as the Ar pressure and power increased. This was considered to be related to the change of the microstructure and the surface morphology by various sputtering conditions. In addition, thinner Si film anodes showed better cycling performance. This phenomenon is caused by the structural stress and peeling off of the Si layer by the high volume change of Si during the charge/discharge process.
        4,000원
        15.
        2008.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 조사에서는 양식업 및 수산업에 있어서 중요한 부분을 차지하고 있는 가막만을 대상으로 수질환경 변화에 대한 이매패류의 군집구조 및 연간변동을 파악하고 물리적 화학적 환경이 이매패류 군집에 미치는 영향을 분석하고자 하였다. 가막만 해역의 12개 정점을 설정하고 2001년부터 2006년까지 4월, 7월, 9월, 11월 계절별로 조사한 결과 이매패류 총 28종이 출현하였으며, 평균 서식밀도는 226.72±196.20 ind. m-2의 변동범
        4,500원
        18.
        1998.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        재충전이 가능한 Li/PEO-LiClO4-PC/LIMn2O4구조의 전고상 전지를 제작하였다. LIMn2O4박막은 RF 마그네트론 스퍼터링 법으로 제작하였으며, 750˚C 부근에서의 급속열처리를 통하여 스피넬 상으로 결정화시킬 수 있었다. 상온 충.방전 시험을 행한 결과, 평균 전압 4V(vs. Li)의 평탄한 방전 전압과 우수한 재충전 능력을 나타내었다.
        4,000원
        19.
        1997.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Characteristics of plasma nitriding and nitrocarburizing for steam treated sintered steels were studied. Fe-0.8%C powder containing Ni, Cu were sintered at 112 and steamed at 52. Temperature of plasma nitriding and nitrocarburizing was varied from 50 to . Gas mixture of nitriding was set at : =80:20 (vol.%), but was added 1~2 vol.% for nitrocarburizing. Steam treatment for sintered steels brought not only the formation of oxide layer but also decarburizing near the surface. Decrease in hardness near the surface resulted from the formation of ferrite due to decarburizing. Thus, the low hardness was recovered not with plasma nitriding but with plasma nitrocarburixing. Wear resistance properties of steamed specimens and ni-trocarburized specimens were better than those of nitrided specimens according to the pin-on-disk wear test. On the other hand, the fatigue life of steamed specimen was shorter than that of nitrocaiburized specimen.
        4,000원
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