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        검색결과 665

        61.
        2019.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Boron-doped amorphous carbon (BDAC) thin films with a regular oxygen reduction reaction (ORR) catalytic activity were synthesized in a hot filament chemical vapor deposition device using a mixture of CH4 and H2 as a gas source and B2O3 as a boron source and then oxidized in air at 380–470 °C for 15–75 min. Scanning electron microscope, transmission electron microscope, Raman spectroscopy, X-ray photoelectron spectroscopy, and electrochemical tests were used to characterize the physical and electrochemical properties of the BDAC catalysts. It was concluded that the BDAC catalyst oxidized at 450 °C for 45 min showed the best ORR catalytic activity in alkaline medium. The oxygen reduction potential and the transfer electron number n, respectively, are − 0.286 V versus Ag/AgCl and 3.24 from the rotating disk electrode experiments. The treated carbon film has better methanol resistance and stability than the commercial Pt/C catalyst.
        4,000원
        62.
        2019.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Aluminum nitride (AlN) has versatile and intriguing properties, such as wide direct bandgap, high thermal conductivity, good thermal and chemical stability, and various functionalities. Due to these properties, AlN thin films have been applied in various fields. However, AlN thin films are usually deposited by high temperature processes like chemical vapor deposition. To further enlarge the application of AlN films, atomic layer deposition (ALD) has been studied as a method of AlN thin film deposition at low temperature. In this mini review paper, we summarize the results of recent studies on AlN film grown by thermal and plasma enhanced ALD in terms of processing temperature, precursor type, reactant gas, and plasma source. Thermal ALD can grow AlN thin films at a wafer temperature of 150~550 oC with alkyl/amine or chloride precursors. Due to the low reactivity with NH3 reactant gas, relatively high growth temperature and narrow window are reported. On the other hand, PEALD has an advantage of low temperature process, while crystallinity and defect level in the film are dependent on the plasma source. Lastly, we also introduce examples of application of ALD-grown AlN films in electronics.
        4,200원
        63.
        2019.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In the historical flow of the Second Revolution of China, the reform and opening, Chinese films have achieved rapidly developing revolution and expansion. These revolutions and expansions are expressed mainly in four respects. That is, the ecological environment of film, the change from closed to open film production mechanism (change), the film management mechanism, from single to pluralization (change), to market from film marketing market (change), from domestic to overseas (change). It is through this transformation and expansion that China has already developed to a movie superpower. But in order for China to become a true film powerhouse, there are still many problems to solve. If these problems are not solved in a timely manner, the dream of a "movie powerhouse" may not be realized quickly. At present, in each field of China, all kinds of projects for full and intensified reform are ongoing, and the formation of a new structure of external openness is accelerating in all directions. Under these circumstances and in the context of the society, Chinese film will be able to make quicker and better development in each field only when they spur to construction of movie power country by continuously strengthening its core competitiveness with continuous realizing and executing the "Film Industry Promotion Act" and reform and opening policies, while adapting to the new changes in the new era and also they can smoothly complete conversion and development from a movie power country to a great film power.
        4,000원
        64.
        2019.07 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        ZnO thin-films are grown on a p-Si(111) substrate by RF sputtering. The effects of growth temperature and O2 mixture ratio on the ZnO films are investigated by scanning electron microscopy (SEM), X-ray diffraction (XRD), and roomtemperature photoluminescence (PL) measurements. All the grown ZnO thin films show a strong preferred orientation along the c-axis, with an intense ultraviolet emission centered at 377 nm. However, when O2 is mixed with the sputtering gas, the half width at half maximum (FWHM) of the XRD peak increases and the deep-level defect-related emission PL band becomes pronounced. In addition, an n-ZnO/p-Si heterojunction diode is fabricated by photolithographic processes and characterized using its current-voltage (I-V) characteristic curve and photoresponsivity. The fabricated n-ZnO/p-Si heterojunction diode exhibits typical rectifying I-V characteristics, with turn-on voltage of about 1.1 V and ideality factor of 1.7. The ratio of current density at ± 3 V of the reverse and forward bias voltage is about 5.8 × 103, which demonstrates the switching performance of the fabricated diode. The photoresponse of the diode under illumination of chopped with 40 Hz white light source shows fast response time and recovery time of 0.5 msec and 0.4 msec, respectively.
        4,000원
        65.
        2019.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In the present study, vanadium oxide(V2O5) films for electrochromic(EC) application are fabricated using sol-gel spin coating method. In order to optimize the EC performance of the V2O5 films, we adjust the amounts of polyvinylpyrrolidone(PVP) added to the solution at 0, 5, 10, and 15 wt%. Due to the effect of added PVP on the V2O5 films, the obtained films show increases of film thickness and crystallinity. Compared to other samples, optimum weight percent(10 wt%) of PVP led to superior EC performance with transmittance modulation(45.43 %), responding speeds(6.0 s at colored state and 6.2 s at bleached state), and coloration efficiency(29.8 cm2/C). This performance improvement can be mainly attributed to the enhanced electrical conductivity and electrochemical activity due to the increased crystallinity and thickness of the V2O5 films. Therefore, V2O5 films fabricated with optimized amount of PVP can be a promising EC material for high-performance EC devices.
        4,000원
        66.
        2019.05 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The passivation of AZ91D Mg alloys through plasma anodization depends on several process parameters, such as power mode and electrolyte composition. In this work, we study the dependence of the thickness, composition, pore formation, surface roughness, and corrosion resistance of formed films on the electrolyte temperature at which anodization is performed. The higher the electrolyte temperature, the lower is the surface roughness, the smaller is the oxide thickness, and the better is the corrosion resistance. More specifically, as the electrolyte temperature increases from 10 to 50 oC, the surface roughness (Ra) decreases from 0.7 to 0.15 μm and the corrosion resistance increases from 3.5 to 9 in terms of rating number in a salt spray test. The temperature increase from 10 to 50 oC also causes an increase in magnesium content in the film from 25 to 63 wt% and a decrease in oxygen from 66 to 21 wt%, indicating dehydration of the film.
        4,000원
        67.
        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
        68.
        2019.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Tungsten trioxide (WO3) is a promising candidate as a photocatalyst because of its outstanding electrical and optical properties. In this study, we prepare WO3 thin films by electrodeposition and characterize the photocatalytic degradation of methylene blue using these films. Depending on the voltage conditions (static and pulse), compact and porous WO3 films are fabricated on a transparent ITO/glass substrate. The morphology and crystal structure of electrodeposited WO3 thin films are investigated by scanning electron microscopy, atomic force microscopy, and X-ray diffraction. An application of static voltage during electrodeposition yields a compact layer of WO3, whereas a highly porous morphology with nanoflakes is produced by a pulse voltage process. Compared to the compact film, the porous WO3 thin film shows better photocatalytic activities. Furthermore, a much higher reaction rate of degradation of methylene blue can be achieved after post-annealing of WO3 thin films.
        4,000원
        69.
        2018.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Inorganic semiconductor compounds, e.g., CIGS and CZTS, are promising materials for thin film solar cells because of their high light absorption coefficient and stability. Research on thin film solar cells using this compound has made remarkable progress in the last two decades. Vacuum-based processes, e.g., co-evaporation and sputtering, are well established to obtain high-efficiency CIGS and/or CZTS thin film solar cells with over 20% of power conversion. However, because the vacuum-based processes need high cost equipment, they pose technological barriers to producing low-cost and large area photovoltaic cells. Recently, non-vacuum based processes, for example the solution/nanoparticle precursor process, the electrodeposition method, or the polymer-capped precursors process, have been intensively studied to reduce capital expenditure. Lately, over 17% of energy conversion efficiency has been reported by solution precursors methods in CIGS solar cells. This article reviews the status of non-vacuum techniques that are used to fabricate CIGS and CZTS thin films solar cells.
        4,000원
        70.
        2018.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Since the late 19 century, the Choseon dynasty forcibly opened the door to western countries, including Japan. In addition, cultural propagation called ‘modernity’ caused subtle changes in dietary life. Based on the theory of colonial dual society, this study examined the dietary modernity in Kyungsung (mid 1930s~early 1940s) when 50 years had passed since the Open-Door policy. Three films, <Turning point of the youngsters>(1934), <Sweet Dream>(1936) and <Spring of Korean Peninsula>(1941) (those made in 1930s~1940s) were analyzed. Twenty six scenes [14 scenes from <Turning point of the youngsters>, five scenes from <Sweet Dream>, and seven scenes from <Spring of Korean Peninsula>] related to the dietary life from films were chosen and classified according three criteria (degree of modernization, main influential countries, and benefit groups from modernization). The degree of modernization of all films was more than 80%. The average proportion of the countries that affected modernization were western (35%), western-Japan (28%) and Japan (20%). Approximately 33, 53 and 14% of the upper, middle, lower classes, respectively, benefited from diet modernization. The main places where modernized dietary culture could be enjoyed were cafes, western restaurants, tea rooms, and hotels. The main food or beverages that were considered as modernized dietary culture were liquor (especially beer), coffee, and western meals. People in Kyungsung in the mid 1930s~early 1940s experienced modernity in dietary life differently according to the social classes and these culture changes were generally accepted as a symbol of modernity.
        4,300원
        71.
        2018.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        중국의 제6세대 감독 중에서 왕차오는 노동자와 사회 주변인의 삶을 다루는 것으로 유명하다. 그의 영화에서 이들의 결말은 비극으로 귀결된다. 프랑스의 영화평론계에서는 그의 세 편의 영화, <안양의 고아>, <낮과 밤>, <럭셔리 카>를 ‘비극 삼부곡’이라 칭한다. 이는 영화에서 나타나는 비극적인 요소뿐만 아니라 인물이나 내용, 주제에서 뚜렷한 유사성과 연속성을 가지고 있다는 전제에서 명명된 것이라고 볼 수 있다. 그렇지만 이 글은 단순하게 영화에 서 나타나는 주인공 혹은 주인공과 관련 있는 인물의 비극적인 삶이나 죽음을 재차 ‘비극적’ 이라고 언급하기 위한 것은 아니다. 오히려 그의 영화는 비록 비극적인 내용을 다루고 있지 만 희망을 염원한다는 것을 밝혀내기 위한 목적이라고 볼 수 있다. 본고에서는 ‘비극 삼부곡’ 에서 나타나는 서사적 은유를 분석하고자 한다. ‘갓난아기’와 ‘강’, ‘江城’ 등의 은유적 장치 분석을 통하여 왕차오 영화에서 나타나는 주제와 특징, 즉 생존과 가족, 윤리와 속죄, 욕망과 귀향 등의 서사를 파악하고자 한다. 이러한 과정을 통하여 그가 세상을 바라보는 시선을 파악할 수 있으리라 판단된다. 종극적으로는 현대 중국에 대한 왕차오 감독의 온기어린 시선을 마주하게 될 것이다.
        4,900원
        72.
        2018.11 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Highly self-cleaning thin films of TiO2-SiO2 co-doped with Ag and F are prepared by the sol-gel method. The asprepared thin films consist of bottom SiO2 and top TiO2 layers which are modified by doping with F, Ag and F-Ag elements. XRD analysis confirms that the prepared thin film is a crystalline anatase phase. UV-vis spectra show that the light absorption of Ag-F-TiO2/SiO2 thin films is tuned in the visible region. The self-cleaning properties of the prepared films are evaluated by a water contact angle measurement under UV light irradiation. The photocatalytic performances of the thin films are studied using methylene blue dye under both UV and visible light irradiation. The Ag-F-TiO2/SiO2 thin films exhibit higher photocatalytic activity under both UV and visible light compared with other samples of pure TiO2, Ag-doped TiO2, and F-doped TiO2 films.
        4,000원
        73.
        2018.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        The passivation of AZ91D Mg alloys by plasma anodization requires deliberate choice of process parameters due to the presence of large amounts of structural defects. We study the dependence of pore formation, surface roughness and corrosion resistance on voltage by comparing the direct current (DC) mode and the pulse wave (pulse) mode in which anodization is performed. In the DC plasma anodization mode, the thickness of the electrolytic oxide film of the AZ91D alloy is uneven. In the pulse mode, the thickness is relatively uniform and the formed thin film has a three-layer structure. The pulse mode creates less roughness, uniform thickness and improved corrosion resistance. Thus, the change of power mode from DC to pulse at 150 V decreases the surface roughness (Ra) from 0.9 μm to 0.1 μm and increases the corrosion resistance in rating number (RN) from 5 to 9.5. Our study shows that an optimal oxide film can be obtained with a pulse voltage of 150 V, which produces an excellent coating on the AZ91D casting alloy.
        4,000원
        74.
        2018.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Conductive and dielectric SiC are fabricated using electroless plating of Ni–Fe films on SiC chopped fibers to obtain lightweight and high-strength microwave absorbers. The electroless plating of Ni–Fe films is achieved using a two-step process of surface sensitizing and metal plating. The complex permeability and permittivity are measured for the composite specimens with the metalized SiC chopped fibers dispersed in a silicone rubber matrix. The original noncoated SiC fibers exhibit considerable dielectric losses. The complex permeability spectrum does not change significantly with the Ni–Fe coating. Moreover, dielectric constant is sensitively increased with Ni–Fe coating, owing to the increase of the space charge polarization. The improvements in absorption capability (lower reflection loss and small matching thickness) are evident with Ni–Fe coating on SiC fibers. For the composite SiC fibers coated with Ni–Fe thin films, a -35 dB reflection loss is predicted at 7.6 GHz with a matching thickness of 4 mm.
        3,000원
        75.
        2018.10 구독 인증기관·개인회원 무료
        Trogoderma variabile B. is one species of well-known stored product insect. This study was conducted to test the perforation ability of larvae of T. variabile on different packaging films which has been widely used in food industry at different thickness. The tested packaging films are polypropylene (PP) 20μm, low density polyethylene (LDPE) 20μm, polyethylene terephthalate (PET) 12μm, PP 30μm and PP 40μm. This investigation was carried out for 7 days. In the same order as the films mentioned above, the perforation rate are 33.33%, 0%, 14.81%, 29.62%, 0%. From these results, the easiest film to perforate among PP, LDPE, PET is PP, and there are significant differences on thickness. Therefore, different type of materials and thickness would be considered to be used for food packaging.
        76.
        2018.10 구독 인증기관·개인회원 무료
        식품의 생물학적 위해요소인 해충과 유해균 및 부패균을 제어하기 위해 실제 포장필름 생산 공정 설비를 이용하여 방충 및 항균 기능성을 갖는 식품용 다층 포장필름을 제조하였다. 우선, 효과적인 활성 물질의 스크리닝 과정을 통해 식품의 대표적 해충인 화랑곡나방 유충(Plodia interpunctella)에 대해 기피력을 나타내는 팔각회향 에센셜 오일과, 황색포도상구균(Staphylococcus aureus) 및 페니실리움(Penicillium roqueforti)에 대해 항균력을 갖는 티몰(thymol)을 필름내 혼입할 활성 물질로 선정하였다. 선정된 활성 물질을 혼입한 폴리우레탄계 코팅액을 polyethylene terephthalate (PET) 12 μm 필름 표면에 코팅하였으며, 방충용 필름은 polypropylene (PP) 30 μm을, 항균용 필름은 low-density polyethylene (LDPE) 30 μm을 적층하여 다층필름의 구조로 제조하였다. Large-scale 생산 공정 설비를 통해 제조된 필름을 활용하여 유충에 대한 기피 효과와 항균력을 측정하였으며, 대조군 필름은 유충에 대한 기피력 및 항균 효과를 보이지 않은 반면, 개발된 방충 및 항균 필름은 화랑곡나방 유충과 두 가지 균에 대해 각각 뛰어난 기피력과 항균 효과를 보였다. 따라서, 본 연구는 식품 포장소재의 대량생산에 활용 가능한 표면 코팅 기술을 개발하고 그 방충효과 및 항균 효과를 입증함으로써 식품 중 생물학적 위해요소의 저감화를 위한 식품 포장 신소재 개발에 기여할 것이다.
        77.
        2018.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        최근 우수한 유연성과 화학적 안정성 등을 가진 고분자 수지와 우수한 기계적 성질 등을 나타내는 무기 재료로 이루어진 나노 복합 시스템으로써 유-무기 하이브리드 코팅 필름에 관한 연구가 활발히 진행되고 있다. 아크릴레이트 단량체로써 사용된 o-phenylphenoxyethyl acrylate (OPPEA)는 1.576의 높은 굴절률을 나타내고, Bisphenol A ethoxylate diacrylate (BAEDA)는 굴절률은 낮지만 경화된 고분자의 경도를 향상시킨다. 또한, 무기 소재로써 사용된 지르코니아는 산화지르코늄으로써 우수한 내구성과 광학특성 등을 나타낸다. 본 연구에서는 광학 특성을 향상시키기 위한 목적으로 아크릴레이트 단량체 중 BAEDA의 함량을 조절하여 필름을 제조한 뒤 연필 경도계와 아베굴절계를 이용하여 광학 특성 변화를 확인하였고, UV-vis spectrophotometer을 이용해 투과도를 비교하여 최적의 조건을 확립하였다. 그리고 실란 커플링제인 γ-methacryloxypropyltrimethoxysilane (MPS)를 사용하여 지르코니아를 소수화 처리하여 아크릴레이트 단량체에 대한 분산성을 향상시키고, 개질 전후의 물에 대한 분산성 변화를 조사하여 물에 대한 친화력이 감소하였음을 확인하였고, FT-IR ATR spectrophotometer를 통해 MPS에 의해 도입된 1716 cm-1에서의 에스터 C=O 결합 peak의 존재를 통해 MPS에 의한 지르코니아 표면의 개질 반응이 진행되었음을 확인하였다. 또한, 지르코니아의 표면에 도입된 규소 원자의 존재는 X 선 형광법을 이용하여 확인하였다. 그리고 화학적으로 개질된 지르코니아를 아크릴레이트 단량체에 도입하여 광경화 필름을 제조하였을 때, 굴절률은 아크릴레이트 자체 필름보다 1.2% 향상되었음을 확인하였고, SEM/EDS mapping 분석을 통해 PET 필름에 코팅된 개질 후 지르코니아가 아크릴레이트 코팅층에 균일하게 분포되어 있음을 알 수 있었다.
        4,200원
        78.
        2018.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Copper oxide thin films are deposited using an ultrasonic-assisted spray pyrolysis deposition (SPD) system. To investigate the effect of substrate temperature and incorporation of a chelating agent on the growth of copper oxide thin films, the structural and optical properites of the copper oxide thin films are analyzed by X-ray diffraction (XRD), field-emssion scanning electron microscopy (FE-SEM), and UV-Vis spectrophotometry. At a temperature of less than 350 ℃, threedimensional structures consisting of cube-shaped Cu2O are formed, while spherical small particles of the CuO phase are formed at a temperature higher than 400 ℃ due to a Volmer-Weber growth mode on the silicon substrate. As a chelating agent was added to the source solutions, two-dimensional Cu2O thin films are preferentially deposited at a temperature less than 300 ℃, and the CuO thin film is formed even at a temperature less than 350 ℃. Therefore the structure and crystalline phase of the copper oxide is shown to be controllable.
        4,000원
        79.
        2018.07 KCI 등재 구독 인증기관 무료, 개인회원 유료
        We fabricated a Li-S battery with post-treated carbon nanotube (CNT) films which offered better support for sulfur, and investigated the effect of the surface properties and pore structure of the post-treated CNT films on Li-S battery performance. Post-treatments, i.e., acid treatment, unzip process and cetyltrimethylammonium bromide (CTAB) treatment, effectively modified the surface properties and pore structure of the CNT film. The modified pore structure impacted the ability of the CNT films to accommodate the catholyte, resulting in an increase in initial discharge capacity.
        4,000원
        80.
        2018.07 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Tungsten oxide(WO3) films with uniform surface morphology are fabricated using a spin-coating method for applications of electrochromic(EC) devices. To improve the EC performances of the WO3 films, we control the heating rate of the annealing process to 10, 5, and 1 oC/min. Compared to the other samples, the WO3 films fabricated at a heating rate of 5 oC/min shows superior EC performances for transmittance modulation(49.5 %), response speeds(8.3 s in a colored state and 11.2 s in a bleached state), and coloration efficiency(37.3 cm2/C). This performance improvement is mainly related to formation of a uniform surface morphology with increased particle size without any cracks by an optimized annealing heating rate, which improves the electrical conductivity and electrochemical activity of the WO3 films. Thus, the WO3 films with a uniform surface morphology prepared by the optimized annealing heating rate can be used as a potential candidate for performance improvement of the EC devices.
        4,000원
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