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        검색결과 102

        21.
        2019.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        상토에 기비로 혼합된 질소의 NH4 +:NO3 - 비율이 ‘녹광’ 고추의 생장에 미치는 영향을 구명하고자 본 연구를 수행하였다. 실험을 위해 코이어 더스트, 피트모스 및 펄라이트를 부피 기준 35:35:30%로 혼합한 상토를 조제 하였으며, 상토원료 혼합과정에서 총 질소 농도가 300mg·L-1인 조건에서 NH4 +:NO3 - 비율을 0:100, 27:73, 50:50, 73:27 및 100:0으로 조절한 5처리를 두어 실험하였다. 질소 외에 다른 필수원소를 포함한 비료는 모든 처리에서 동일한 농도로 조절하였고, 비료를 포함한 상토를 50구 플러그 트레이에 충진한 뒤 고추 종자를 파종하였다. 파종 전과 파종 후 상토의 pH, EC 및 다량원소 농도를 분석하였으며, 파종 7주 후에는 지상부 생장 조사와 식물체 무기원소 함량을 분석하였다. 파종 전 상토 pH는 질소 비율에 따른 차이가 뚜렷하지 않았으나 생장이 진행되면서 NO3 -의 비율이 높은 처리의 상토 pH가 상승하였다. NH4 +의 비율이 클수록 파종 전 상토의 EC가 높았으나 모든 처리의 EC가 파종 3주 후부터 급격히 낮아지는 경향을 보였다. 고추묘 생장이 진행됨 에 따라 상토의 NH4 +-N, NO3 --N 그리고 다른 종류의 다량원소 농도가 EC 변화와 유사한 경향을 보이며 낮아 졌다. 파종 7주 후 고추의 지상부 생장을 조사한 결과 NH4 +:NO3 - 비율이 27:73과 50:50 처리구에서 전반적인 생장이 우수하였고, NH4 + 비율이 73% 이상일 경우 저조 한 생장을 보였다. 또한 생장이 가장 우수하였던 50:50(NH4 +:NO3 -) 처리구의 식물체내 T-N, K, Ca 및 Mg 등 다량 무기원소 함량이 가장 높았다. 이와 같은 결과를 고려할 때 ‘녹광’ 고추의 플러그 묘 생장을 위해 서는 상토에 기비로 혼합하는 전체 질소 중 NH4 +의 비율을 27% 또는 50%로 조절하는 것이 묘 생장에 유리할 것으로 판단하였다.
        4,000원
        22.
        2019.04 구독 인증기관·개인회원 무료
        In order to industrialization of the entomopathogenic nematode (EPN) isolated in Korea, it is necessary to switch to infective juveniles. Since the conversion to infective juveniles in the end of solid culture is important against the outside environment, it has a great influence on insecticidal efficacy and shelf life. We investigated whether the concentration of CO2 and NH3 at the end of the solid culture was artificially increased to affect the infective juvenile induction rate. Optimal exposure time for conversion to infective juveniles was 5 minutes for CO2 and 3 minutes for NH3. Optimal treatment time was 9 days after EPN inoculation for both CO2 and NH3. And optimum concentration was 80~90% for both CO2 and NH3 for EPN infective juveniles stage conversion.
        24.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The nitrogen isotope value in both ammonium and nitrate ion were determined at 9 stations during both June and August 2016, in order to understand the origin of DIN at the Han river. δ15N-NO3 and δ15N-NH4 values in 8 stations (CP, SB, MHC, P4, SJ, SBC, P2, SC) were no significant variation. However δ15N-NO3 and δ15N-NH4 values in KK (Kyeongan stream) showed significant different in comparison with 8 stations, with an apparent increase of nitrogen isotope values. These results indicate that antropogenic nitrogen source influence on KK station. Also the δ13C and δ15N isotope ratio of phytoplankton (Diatom and Cyanobacteria) in KK (Kyeongan stream) showed heavier values, compared to other study stations. These results indicate that nitrogen isotope value in phytoplankton effects by different nitrogen source in study sites. These results suggest that the analysis of stable isotope ratios is a simple but useful tool for the identification of dissolved inorganic nitrogen origin in aquatic environments.
        4,000원
        25.
        2017.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In order to compare greenhouse gases emission from different animal manures and to explore how different animal manures effect on soil mineralization, three kinds of materials, cattle, goat and chicken manure were amended to soil for 14 days incubation as CtS (cattle manure-amended soil), GS (goat manure-amended soil) and ChS (chicken manure-amended soil). Cumulative NH3 emissions in all treatments were rapidly increased until day 7 and then it was slightly increased in three manure-amended soils but maintained in control until day 14. GS had the highest NH3 emission at 0.14 mg kg-1 during the entire experimental period. Emissions of CO2 were highly increased by 7.8-, 9.0- and 12.4-fold in CtS, GS and ChS, respectively, compared to control at day 14. A significant increase of N2O emission in all treatments occurred within 5 days and then it was slightly increased until day 14. N2O emission was 2-fold higher in all manure-amended soils than that of control. Compared to day 1, inorganic N (NH4 + plus NO3 --N) content was highly increased in all four treatments at day 14. The increase rate was the highest in CtS treatment. Net N mineralization was increased by 4.0-, 2.4- and 2.9-fold in CtS, GS and ChS, respectively, compared to control. These results indicate that increase of NH3, CO2 and N2O gas emissions was positively related to high N mineralization.
        4,000원
        26.
        2017.06 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Organometal halide perovskite materials, due to the tunability of their electronic and optical properties by control of composition and structure, have taken a position of significant importance in optoelectronic applications such as photovoltaic and lighting devices. Despite numerous studies on the structure - property relationship, however, practical application of these materials in electronic and optical devices is still limited by their processability during fabrication. Achieving nano-sized perovskite particles embedded in a polymer matrix with high loading density and outstanding photoluminescence performance is challenging. Here, we demonstrate that the careful control of nanoparticle formation and growth in the presence of poly(methyl methacrylate) results in perovskite nanoparticle - polymer nanocomposites with very good dispersion and photoluminescence. Furthermore, this approach is found to prevent further growth of perovskite nanoparticles, and thus results in a more uniform film, which enables fabrication using the perovskite nanoparticles.
        4,000원
        27.
        2017.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Mineralization is an important biological process for conversion of organic nitrogen (N) to inorganic N which can be used by plants directly. To investigate the effect of different manures on soil mineralization, the soil amended with cattle (CtM), goat (GM), chicken manure (ChM) and pig slurry (PS) were incubated under in vitro condition and ammonium N (NH4 +-N), ammonification rate and ammonia emission were determined for eighty-four days. NH4 +-N was the highest in PS-amended soil for the whole experimental period. NH4 +-N in PS-amended soil was gradually decreased until day 84, whereas it was rapidly decreased for the first 14 days and then slightly increased until 84 days in ChM-, CtM- and GM-amended soil. The ammonification rate showed negative value for the first 14 days in all treatments. From day 14, ammonification rate started to increase in CtM- and ChM-amended soil, whereas it was maintained in GM- and PS-amended soil until day 84. The daily ammonia emission was the highest in PS-amended soil (41mg kg-1 d-1), followed by CtM-, ChM-, and GM-amended soil at day 1. It was gradually decreased until day 84 in all treatments. The total NH3 emission was the highest in PS-amended soil with 0.6 mg kg-1 for 84 days, while less than 0.1 mg kg-1 in three other plots. These results indicate that different manures showed different soil ammonification rate and NH3 emission.
        4,000원
        28.
        2016.12 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        In this study, we used activated carbon(AC) as a carbon source, along with zeolite, to prepare spherical carbons using sucrose, starch and phenolic resin(PR) as binder material. The physicochemical characteristics of the three samples(AZ4P, AZ6P and AZ8P) were examined by BET, XRD, SEM, EDX, H2S/NH3 gas adsorption, compressive strength and ignition test techniques. Through comparative analysis of the compressive strength and ignition test results the AZ8P sample was found to have the best hardness and the highest temperature resistance capacity. After activation, the AZ8P sample had the best H2S adsorption capacity, and AZ6P was the most suitable for the adsorption of ammonia.
        4,000원
        29.
        2016.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Fe-based pigments have attracted much interest owing to their eco-friendliness. In particular, the color of nanosized pigments can be tuned by controlling their size and morphology. This study reports on the effect of length on the coloration of β-FeOOH pigments prepared using an NH4OH solution. First, rod-type β-FeOOH is prepared by the hydrolysis of FeCl3·6H2O and NH4OH. When the amount of NH4OH is increased, the length of the rods decreases. Thus, the length of the nanorods can be adjusted from 10 nm to 300 nm. The color of β-FeOOH changes from orangered to yellow depending on the length of β-FeOOH. The color and phase structure of β-FeOOH is characterized by UVvis spectroscopy, CIE Lab color parameter measurements, transmission electron microscopy (TEM), scanning electron microscopy (SEM), and powder X-ray diffraction (XRD).
        4,000원
        30.
        2016.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Taboo character is typical phenomenon of Chinese characters system, it is considered as the effective key in decrypting the date of Han-Nom texts inscirption texts. Such key is maintained clearly on the ancient books add steles of Vietnam, specially Taboo characters system in the insription texts of Tran Dynasty (1225-1400). Based on research results, we have found a new form of Taboo character previously published in studies in Vietnam Taboo characters. Such new characters forms have helped us easily discover in cription texts at the date of Tran dynasty in Ninh Binh. This is the useful and reliable source for researching of Vietnam Taboo characters in particular and ancient books of Vietnam in general.
        4,500원
        31.
        2016.04 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Fabrication of iron oxide/carbon nanotube composite structures for detection of ammonia gas at room temperature is reported. The iron oxide/carbon nanotube composite structures are fabricated by in situ co-arc-discharge method using a graphite source with varying numbers of iron wires inserted. The composite structures reveal higher response signals at room temperature than at high temperatures. As the number of iron wires inserted increased, the volume of carbon nanotubes and iron nanoparticles produced increased. The oxidation condition of the composite structures varied the carbon nanotube/iron oxide ratio in the structure and, consequently, the resistance of the structures and, finally, the ammonia gas sensing performance. The highest sensor performance was realized with 500 oC/2 h oxidation heat-treatment condition, in which most of the carbon nanotubes were removed from the composite and iron oxide played the main role of ammonia sensing. The response signal level was 62% at room temperature. We also found that UV irradiation enhances the sensing response with reduced recovery time.
        4,000원
        32.
        2016.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The study analyzed performance assessment factors of odor sensors from 4 different manufacturers, including minimum detection limit, humidity stability and temperature stability. In the minimum detection limit assessment, only one electrochemical gas sensor was able to detect ammonia and hydrogen sulfide at the concentration of 5 ppb. The standard deviation ratio was over 10%, and it increased as humidity rose. The range of temperatures in which the electrochemical and photoionization gas sensors could function well was between 25oC and 40oC, and the sensor output values were unstable at low temperatures. Regarding the temperature stability of the metal oxide semiconductor sensor for measuring complex odors, the sensor output values dropped considerably to 0~10oC, and were similar to the concentrations of odor gases generated at 25oC. The results of the test of odor sensor outputs after temperature and humidity pre-treatment revealed that the respective stable output values at 50% humidity and 25oC were similar to the concentrations of manufactured odors. In terms of temperature and humidity stability of the NH3, H2S and Complex odor sensors, all target substances had stable output values at 25~40oC and 50~65% relative humidity, and unstable values at low temperatures and high humidity. Therefore, implementing pretreatment systems including temperature and humidity correction (25~40oC, 50~65% RH) is necessary for the stable use of odor sensors.
        4,900원
        33.
        2015.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Aluminum nitride, a compound semiconductor, has a Wurtzite structure; good material properties such as high thermal conductivity, great electric conductivity, high dielectric breakdown strength, a wide energy band gap (6.2eV), a fast elastic wave speed; and excellent in thermal and chemical stability. Furthermore, the thermal expansion coefficient of the aluminum nitride is similar to those of Si and GaAs. Due to these characteristics, aluminum nitride can be applied to electric packaging components, dielectric materials, SAW (surface acoustic wave) devices, and photoelectric devices. In this study, we surveyed the crystallization and preferred orientation of AlN thin films with an X-ray diffractometer. To fabricate the AlN thin film, we used the magnetron sputtering method with N2, NH3 and Ar. According to an increase in the partial pressures of N2 and NH3, Al was nitrified and deposited onto a substrate in a molecular form. When AlN was fabricated with N2, it showed a c-axis orientation and tended toward a high orientation with an increase in the temperature. On the other hand, when AlN was fabricated with NH3, it showed a-axis orientation. This result is coincident with the proposed mechanism. We fabricated AlN thin films with an a-axis orientation by controlling the sputtering electric power, NH3 pressure, deposition speed, and substrate temperature. According to the proposed mechanism, we also fabricated AlN thin films which demonstrated high aaxis and c-axis orientations.
        4,000원
        34.
        2014.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study was performed to obtain high conversion efficiency of NH3 and minimize generation of nitrogen oxides using metal-supported catalyst with Ag : Cu ratio. Through structural analysis of the prepared catalyst with Ag : Cu ratio ((10-x)Ag–xCu (0≤ x ≤6)), it was confirmed that the specific surface area was decrease with increasing metal content. A prepared catalysts showed Type Ⅱ adsorption isotherms regardless of the ratio Ag : Cu of metal content, and crystalline phase of Ag2O, CuO and CuAl2O was observed by XRD analysis. In the low temperature(150∼200 ℃), a conversion efficiency of AC_10 recorded the highest(98%), whereas AC_5 (Ag : Cu = 5 : 5) also showed good conversion efficiency(93.8%). However, in the high temperature range, the amounts of by-products(NO, NO2) formed with AC_5 was lower than that of AC_10. From these results, It is concluded that AC_5 is more environmentally and economically suitable.
        4,000원
        35.
        2013.08 구독 인증기관 무료, 개인회원 유료
        The main objective of this work is to perform experimental analyses of a absorption refrigeration system using a new refrigerant-sorbent pair as the working pair. The active component of sorbent is sodium thiocyanate (NaSCN). Ammonia (NH3) is chosen as refrigerant. As a result of these, it is concluded that the unit exhibits good cooling performance and the average cooling capacity is approximately 28.8kW and the average coefficient of performance (COP) of absorption system is 0.56. The unit is a thermal compressor which uses low-grade waste heat to generate refrigeration (cooling or freezing).
        4,000원
        36.
        2012.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aims to evaluate the relationship with the concentration and odor intensity using the odor sensory method for 4 types of sulfur compounds, ammonia, and trimethylamine. For the measurement, 13 panelists were selected by several criteria through a panel test. Panelists chosen for their closely similar sensitivities provide more reproducible values. The estimation showed that the correlation of the concentration with odor intensity for the 6 compounds can be reasonably expressed by the equation I=Aㆍlog C+B (I: Odor Intensity, C: material concentration, A: material constant, B: constant). The result of this study is suggested to be used as a base data for research on measures to improve the regulation standards for complex odor concentration on site boundary in operation, as well as a correlation between the concentration and odor intensity for the designated foul odor substances, and their characteristics.
        4,000원
        37.
        2012.09 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We investigated cleaning effects using NH4OH solution on the surface of Cu film. A 20 nm Cu film was deposited on Ti / p-Si (100) by sputter deposition and was exposed to air for growth of the native Cu oxide. In order to remove the Cu native oxide, an NH4OH cleaning process with and without TS-40A pre-treatment was carried out. After the NH4OH cleaning without TS-40A pretreatment, the sheet resistance Rs of the Cu film and the surface morphology changed slightly(δRs:~10mΩ/sq.). On the other hand, after NH4OH cleaning with TS-40A pretreatment, the Rs of the Cu film changed abruptly (δRs:till~700mΩ/sq.); in addition, cracks showed on the surface of the Cu film. According to XPS results, Si ingredient was detected on the surface of all Cu films pretreated with TS-40A. This Si ingredient(a kind of silicate) may result from the TS-40A solution, because sodium metasilicate is included in TS-40A as an alkaline degreasing agent. Finally, we found that the NH4OH cleaning process without pretreatment using an alkaline cleanser containing a silicate ingredient is more useful at removing Cu oxides on Cu film. In addition, we found that in the NH4OH cleaning process, an alkaline cleanser like Metex TS-40A, containing sodium metasilicate, can cause cracks on the surface of Cu film.
        4,000원
        38.
        2012.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aims to evaluate the relationship with the concentration and dilution factor using the Air Dilution Olfactory Method, which is suggested in the Standard Method of Odor Compounds, by measuring dilution factor for 4 types of sulfur compounds, ammonia, and trimethylamine. For the measurement, 13 panelists were selected by several criteria through a panel test. Panelists chosen for their closely similar sensitiviyies provide more reproducible values. The estimation showed that the correlation of the concentration with dilution factor for the 6 compounds can be reasonably expressed by the equation logC=AfㆍlogD+F (Af: material costant, F: constant). The result of this study is suggested to be used as a base data for research on measures to improve the regulation standards for complex odor concentration on site boundary in operation, as well as a correlation between the concentration and dilution factor for the designated foul odor substances, and their characteristics.
        4,000원
        40.
        2011.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Magnesium hydroxide sulfate hydrate whiskers (, abbreviated 513 MHSH) were prepared using hydrothermal reaction with magnesium oxide (MgO) and magnesium sulfate () as the starting materials. The effects of the molar ratio of /MgO and amount of were studied. As a result, 513 MHSH whiskers co-existed with hexagonal plate at low concentration of . The molar ratio of /MgO was 7:1, uniform 513 MHSH whiskers were formed without impurity such as . Appropriate amount of has affected to formation of high quality MHSH. Their morphologies and structures were determined by powder X-ray diffraction (XRD) scanning electron microscopy (SEM) and thermo-gravimetric analyzer (TGA).
        4,000원
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