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        검색결과 835

        101.
        2018.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        상토에 기비로 혼합된 질소 시비수준 차이가 ‘녹광’ 고추의 플러그 묘 생장에 미치는 영향을 구명하기 위해 본 연구를 수행하였다. 코이어더스트, 피트모스 그리고 펄라이트를 용적기준 35, 35 및 30%로 혼합한 상토를 조제할 때 질소를 0, 100, 250, 500, 750, 1,000 및 1,500mg·L-1로 농도를 조절하여 첨가하였고, 질소를 제외한 필수원소는 모든 처리에서 동일한 농도로 조절하였다. 비료를 포함한 상토를 50-cell 트레이에 충진한 후 종자 를 파종하였다. 파종 후 매주 pH와 EC 측정, 파종 0, 3 및 7 주 후 상토의 다량원소 농도 분석, 그리고 파종 7 주 후에 지상부 생장 조사와 식물체 무기원소 함량을 분석하였다. 파종 전 상토의 pH는 질소수준별 차이가 크지 않았지만 육묘기간이 길어질수록 처리간 차이가 커지는 경향이었다. 상토의 EC는 파종 전 질소 시비수준 별 뚜렷한 차이를 보였지만, 파종 4주 이후부터 처리간 차이가 적어졌고, 7주 후에는 모든 처리에서 유사한 수 준으로 측정되었다. 상토 추출용액의 NH4-N 및 NO3-N 농도는 EC와 유사한 경향을 보이며 낮아졌고, 다량원소 농도 역시 파종 3주 이후에 감소폭이 더 커졌다. 파종 후 7주 후 조사한 고추 유묘의 지상부 생장은 500 및 750mg·L-1 처리구에서 우수하였으며, 1,000mg·L-1 이상의 처리구에서는 질소 무시비구와 비슷한 수준으로 생장이 저조하였다. 파종 7주 후 분석한 식물체내 N 함량은 질소 시비수준이 높아질수록 직선적으로 증가하였으며, 지상부 생장이 우수하였던 500 및 750mg·L-1 시비구가 각 각 5.13 및 5.31%로 분석되었다. 이상의 결과를 고려하 였을 때 고추의 유묘 생장을 위해서는 기비로서의 질소 시비수준을 500 또는 750mg·L-1으로 조절하는 것이 바람직하며, 건물중에 기초한 N 함량이 5.1~5.3% 수준으 로 시비농도를 조절하는 것이 바람직하다고 판단하였다.
        4,000원
        102.
        2018.03 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Nitrogen (N)-doped protein-based carbon as platinum (Pt) catalyst supports from tofu for oxygen reduction reactions are synthesized using a carbonization and reduction method. We successfully prepare 5 wt% Pt@N-doped protein-based carbon, 10 wt% Pt@N-doped protein-based carbon, and 20 wt% Pt@N-doped protein-based carbon. The morphology and structure of the samples are characterized by field emission scanning electron microscopy and transmission electron micro scopy, and crystllinities and chemical bonding are identified using X-ray diffraction and X-ray photoelectron spectroscopy. The oxygen reduction reaction are measured using a linear sweep voltammogram and cyclic voltammetry. Among the samples, 10 wt% Pt@N-doped protein-based carbon exhibits exellent electrochemical performance with a high onset potential of 0.62 V, a high E1/2 of 0.55 V, and a low ΔE1/2= 0.32 mV. Specifically, as compared to the commercial Pt/C, the 10 wt% Pt@N-doped proteinbased carbon had a similar oxygen reduction reaction perfomance and improved electrochemical stability.
        4,000원
        103.
        2018.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objectives of this study were to evaluate the removal characteristics of total nitrogen, the influence factor of denitrification and the optimum operating condition in the pigment wastewater treatment using PAC-A/O process. The operating conditions of PAC-A/O process were mean BOD volumetric loading 0.86 kgBOD/m3/day, mean F/M ratio 0.072∼0.13 kgBOD/kgMLVSS/day and mean C/N ratio 3.47, respectively. The conditions of anoxic process in the field plant test were mean pH 8.3∼8.7 and mean temperature 34.1~44.0℃. The ORP bending point knee was eventually appeared in the ORP -107 mV and NO3 --N removal efficiency was increased according to the ORP decrease. In the ORP -107 mV below condition, the removal efficiency of T-N and NO3 --N was 92.3∼95.0% and 98.5∼99.7%. Denitrification rate was calculated to be 1.581∼1.791 mg NO3 --N/gMLSS/hr. The experimental results showed that the ORP control in the PAC-A/O process could be an effective method for treatment of pigment wastewater.
        4,000원
        105.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Nitrogen (N) loading from domestic, agricultural and industrial sources can lead to excessive growth of macrophytes or phytoplankton in aquatic environment. Many studies have used stable isotope ratios to identify anthropogenic nitrogen in aquatic systems as a useful method for studying nitrogen cycle. In this study to evaluate the precision and accuracy of denitrification bacteria method (Pseudomonas chlororaphis ssp. Aureofaciens (ATCC® 13985)), three reference (IAEA-NO-3 (Potassium nitrate KNO3), USGS34 (Potassium nitrate KNO3), USGS35 (Sodium nitrate KNO3)) were analyzed 5 times repeatedly. Measured the δ15N-NO3 and δ18O-NO3 values of IAEA-NO-3, USGS 34 and USGS35 were δ15N: 4.7±0.1‰ δ18O: 25.6±0.5‰, δ15N: -1.8±0.1‰ δ18O: -27.8±0.4‰, and δ15N: 2.7±0.2‰ δ18O: 57.5±0.7‰, respectively, which are within recommended values of analytical uncertainties. Also, we investigated isotope values of potential nitrogen source (soil, synthetic fertilizer and organic-animal manures) and temporal patterns of δ15N-NO3 and δ18O-NO3 values in river samples during from May to December. δ15N-NO3 and δ18O-NO3 values are enriched in December suggesting that organic-animal manures should be one of the main N sources in those areas. The current study clarifies the reliability of denitrification bacteria method and the usefulness of stable isotopic techniques to trace the anthropogenic nitrogen source in freshwater ecosystem.
        4,200원
        106.
        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
        107.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Compound specific isotope analysis of amino acids (CSIA-AAs) is being highlighted as an alternative approach for overcoming some restrictions in application of stable isotope analysis of bulk tissue (SIA) for trophic position (TP) estimation. However, this approach has rarely been applied in Korea. The present study determines TP of two Polychaeta (Nephtyidae and Glyceridae) and two fish species (Platycephalus indicus and Lophius litulon) collected from the Geum River estuary using nitrogen isotope ratio of amino acid and compared with the TP values estimated by SIA. The Polychaeta species, sampled in two sites, showed similar TP between SIA (2.7 and 3.1) and CSIA-AAs (2.6 and 3.1). However, for both fish species, TP values displayed a large difference between SIA (3.1 and 2.3) and CSIA-AAs (3.8 and 3.7). In this study TP values estimated by CSIA-AAs showed more similar to the previously reported gut content analysis of both fishes compared with the results of SIA. Current study suggests the applicability of nitrogen isotope ratio of amino acid to understand coastal ecosystem structure and trophic ecology.
        4,000원
        110.
        2017.10 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study aimed to investigate growth rate and nutrient consumption of Chlorella vulgaris according to different light irradiation interval. Applied light irradiation intervals were 12 hr, 4 hr, 1 hr, and 1 min. The light source was flexible LED(Blue:Red=1:1), light intensity was 200 PPFD and Light/Dark cycle was 1:1. As a result, growth rate and nutrient removal efficiencies showed no significant differences depending on the light irradiation interval. Considering the reproduction characteristics of applied microalgae cultures of this study, this is thought to be one of the possible reasons of above results. Because Chlorella vulgaris performs an asexual reproduction and it is known that there is no significant relationship between light irradiation interval and growth rate, including nutrient consumption in case of asexual reproduction.
        4,000원
        111.
        2017.10 구독 인증기관·개인회원 무료
        Since methyl bromide(MB) has been designated as ozone deplete substance(ODS) by Montreal protocol (1989), many MBalternative fumigants like ethyl formate and phosphine gas were developed and commercialized. Ethyl formate(EF) is an effectiveMB alternative fumigant to control insect pests on imported fresh commodities. It is important to develop a proper evaporationmethod to apply EF on large scale fumigation because EF has a high boiling point(54℃). Recently, concurrent treatment ofethyl formate and nitrogen(EF+N2 treatment) has been newly developed. At preliminary test, EF+N2 treatment showed goodevaporation rate and showed high efficacy on quarantine pests without phytotoxicity on fresh commodities. In this trial, we’veapplied the EF+N2 treatment on imported orange and lemon at pilot scale (0.5m3, 10m3) containers and commercial scale containerto validate efficacy and phytotoxicity. 70g/m3 of EF liquid was applied on orange and lemon by EF+N2 treatment method,and showed 100% mortality on tested insect pest(Tetranychus urticae) without phytotoxicity at 0.5m3 and 10m3 scale fumigationtrials, respectively. At commercial scale trial, EF+N2 treatment also showed 100% efficacy on T. urticae and there was nophytotoxic symptoms on imported orange and lemon fruit. These results indicate that the newly developed EF+N2 treatmenthas a potential as a MB alternative, and can be applied on imported fresh commodities for quarantine and pre-shipment purpose.
        112.
        2017.10 구독 인증기관·개인회원 무료
        This study investigated growth response of Korean exotic woody plants Acer saccharinum L. and Amorpha fruticosa L., on the climate change. We also examined the growth on nitrogen treatment of them. Acer saccharinum L. and Amorpha fruticosa L. were sown in March 2014 and then transplanted to each environment conditions in May 2015. Atmospheric conditions were divided into the outdoor environment treatment(AC-AT), the temperature elevation treatment(AC-ET), and the climate change treatment (EC-ET). In each atmospheric condition, non-treated (Control; C) pots were placed without nitrogen fertilizer treatment. Acer saccharinum L. treated 2g (N1), 20g (N2) of nitrogen fertilizer, respectively. And Amorpha fruticosa L. treated 1g (N1), 5g (N2) of nitrogen fertilizer, respectively. After the adaptation to each environmental condition until October 2016, the length, diameter of stem-root border, aboveground biomass, underground biomass, and leaves weight of Acer saccharinum L. and Amorpha fruticosa L. were measured. The above results show that Acer saccharinum L. was affected the length of shoot under conditions of increased temperature. Amorpha fruticosaL. means that When the nitrogen increases under the condition that the temperature and the CO2 concentration are increased together, the length of shoot and the Diameter of stem-root increase, but the Underground biomass decrease.
        113.
        2017.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The objective of this study was to quantify and characterize the inorganic nitrogen and phosphorus outflow loading from different water managements in paddy fields. We investigated the NO3-N, NH4-N, and PO4 in runoff from paddy fields in Iksan. The three different water management treatments were conventional continuous irrigation at 4 and 8 cm water levels, and intermittent irrigation at a 4 cm water level. The concentration of NO3-N at the early growth stage in surface water was 6.11 mg L-1, and then it gradually decreased. The downward curve increased slightly with additional nitrogen fertilization at the panicle initiation stage, and then it continued to decrease. The NH4-N concentration was 5.26 mg L-1, and that of PO4 was 0.70 mg L-1 at the early growth stage. However, the concentration of NO3-N peaked at 8.79 mg L-1 directly after transplantation and then decreased rapidly throughout the growing season. The amount of NH4-N runoff was 1.86 kg ha-1 in the plot with intermittent irrigation, and 2.0 kg ha-1 and 2.1 kg ha-1 in the plots with water depths of 4 and 8 cm, respectively. The NO3-N runoff was 7.43 kg ha-1 in the plot with intermittent irrigation, 8.62 kg ha-1 in the plot with a water depth of 4 cm, and 10.25 kg ha-1 in the plot with a water depth of 8 cm. In addition, the PO4 runoff was 0.42 kg ha-1 in the plot with intermittent irrigation, 0.48 and 0.55 kg ha-1 in the plots with water depths of 4 and 8 cm, respectively. The saving effect of irrigation water was 28.5% than that of conventional water management treatments, and the amount of nitrogen runoff was decreased by 18.5% with intermittent irrigation. However, the phosphorus runoff was not different between the different water management treatments in paddy fields.
        4,000원
        114.
        2017.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        합성폐수 내의 유기물(COD), 질산성 질소, 인산이온을 제거하기 위한 폐수처리 시스템 개 발을 위한 연구를 수행하였다. 먼저 COD는 HClO의 산화 반응에 의해 거의 100 % 제거되었으며 전기 화학적 처리에 의해 질산성 질소가 암모니아성 질소로 환원되지만, 암모니아성 질소는 HClO 처리에 의 해 질산성 질소로 재 산화 되었다. 암모니아성 질소는 가열 증발 처리에 의하여 거의 100% 제거 되었 으며 HClO 처리를 하여도 재 산화되는 암모니아성 질소는 나타나지 않았다. 인산 이온은 pH에 따라 금속 착염을 형성함으로써 침전 처리에 의해 제거할 수 있었으며 전기화학적 처리와 HClO 처리를 통 하여 COD 99.5 % 이상, 질소 97.3 %, 인 91.5 %의 제거 효율을 얻을 수 있었다.
        4,000원
        115.
        2017.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        상토에 기비로 혼합된 질소 수준이 무 ‘속성대형봄무’ 의 플러그 묘 생장에 미치는 영향을 구명하기 위하여 본 연구를 수행하였다. 펄라이트:코이어더스트:피트모스를 용적기준 30:35:35%의 비율로 조절한 상토를 조제하는 과정에서 0, 100, 250, 500, 750, 1,000 및 1,500mg·L-1 비율로 질소를 기비로써 혼합하고 72구 플러그 트레이에 충전하였다. 이후 무 종자를 파종하고 4주간 재배한 후 지상부 생육과 식물체내 무기원소 함량을 분석하였으며, 상토 추출액의 pH, EC 및 무기원소 농도는 매주 분석하였다. 파종 후 질소 시비수준이 높을수록 pH가 낮고 EC가 높은 경향이었지만, 생장이 진행됨에 따라 모든 처리의 pH가 점차 상승하고 EC가 낮아지는 경향을 보였다. 상토의 EC 및 NH4와 NO3 농도는 파종 2주 후까지 완만하게, 2주 후부터 4주 후까지 급격히 낮아지는 경향을 보였다. 질소시비수준에 따른 무 유묘의 생장반응을 조사한 결과 재배 2주후에는 질소 시비수준이 250mg·L-1 처리의 생장이 가장 우수하고 이보다 낮거나 높은 질소 농도에서 생장이 저조한 2차곡선회귀적 경향을, 그리고 파종 4주 후에는 500mg·L-1 처리에서 생장이 가장 우수하고 높거나 낮은 질소 시비수준에서 생장이 저조한 2차곡선회귀적 경향을 나타냈다. 재배 4주 후 질소 시비수준이 높아질수록 T-N은 높고, K, Mg 및 Ca 함량이 낮아지는 경향을 보였으며, 생장이 우수하였던 250과 500mg·L-1 시비구의 질소 함량이 각각 4.96%와 5.74%였다. 이상의 결과를 요약하면 질소 시비수준을 250mg·L-1 이하로 조절해야 식물체가 어린 시기에 고농도 질소에 의해 생장 억제를 피할 수 있다고 판단하였다.
        4,000원
        116.
        2017.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        The present study was conducted to determine the optimal supplementation level of beta-mannanase in the diet of laying hens. A total of 320 Hy-Line Brown layers (80 weeks of age) were assigned randomly into four groups on the basis of laying performance. Each treatment had eight replicates with 10 birds each (80 birds per treatment). Two hens were caged individually. Treatments were basal diet supplemented with 0 (control), 0.04, 0.08, and 0.16% beta-mannanase during the nine-week feeding period. Laying hens fed diets supplemented with increasing levels of beta-mannanase had increased (linear, p<0.05) overall egg production and egg mass. In addition, these hens had greater retention of dry matter, crude protein, gross energy, calcium, and mannan (linear, p<0.05). Dietary beta-mannanase treatments had no effect on blood metabolites such as total carbohydrate, triglycerides, glucose, total protein, and blood urea nitrogen, or excreted ammonia nitrogen and volatile fatty acids. The results obtained in present study indicate that dietary supplementation of beta-mannanase has the potential for improving the performance of laying hens. The optimal supplementation level is 0.04% beta-mannanase in the diet.
        4,000원
        118.
        2017.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 해양플랜트설비 건조 현장에서 사용되고 있는 기존 고온 오일 플러싱 장비에 대한 성능개선을 위해 기존의 플 러싱 장치에 사용되던 오일에 질소가스를 혼합한 고온 오일 플러싱 시스템에 대하여 국제표준화기구 코드(ISO code)를 기준으로 이론적 연구를 수행하였다. 연구를 위해 오일-질소가스 혼합유체 플러싱 시스템 공정을 설계 후 청정성능에 영향을 주는 혼합유체의 혼합비율, 온도, 레이놀즈수 및 액상분율 등에 대한 공정모사 결과도 분석하였다. 그 결과 관 직경과 가스상의 체적분률이 일정한 상태에서 혼합유 체의 체적유량이 증가될수록 수평 유압배관 입출구의 액상분율 차이  값은 증가하게 되고 배관길이 방향의 위치에 따라 오일과 질 소가스 기포 사이의 상분포가 달라짐을 확인했다. 이러한 상분포의 변화는 오일-질소가스 혼합유체 플러싱 시스템의 청정성능에도 커다 란 영향을 줄 것으로 예상된다.
        4,000원
        119.
        2017.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper introduces a nitrogen-doped ordered mesoporous carbon (NOMC) derived from glucosamine with hybrid capacitive behaviors, achieved by successfully combining electrical double-layer capacitance with pseudo-capacitance behaviors. The nitrogen doping content of the fabricated NOMC reached 7.4 at% while its specific surface area (SBET) and total pore volume reached 778 m2 g−1 and 1.17 cm3 g−1, respectively. A dual mesoporous structure with small mesopores centered at 3.6 nm and large mesopores centered at 9.9 nm was observed. The specific capacitance of the reported materials reached up to 328 F g−1, which was 2.1 times higher than that of pristine CMK-3. The capacitance retention rate was found to be higher than 87.9% after 1000 charge/discharge cycles. The supplementary pseudocapacitance as well as the enhanced wettability and conductivity due to the incorporation of nitrogen heteroatoms within the carbon matrixes were found to be responsible for the excellent capacitive performance of the reported NOMC materials.
        4,000원
        120.
        2017.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        치자 껍질의 70% methanol, ethyl acetate (EA) 및 distilled water (DW)의 용매 별 추출물 의 total phenol 함량 및 질소 산화물 소거능, 환원력, β-carotene 탈색을 이용한 항산화력 및 지질과 산화 저해능 측정을 통하여 치자의 기능성 식품 소재로서의 가치를 검토한 결과, anthocyanin 함량은 3.519±0.635 mg/100 g DW로 나타났으며, 용매 별 추출 수율은 DW (39.87%), 70% methanol (36.26%), EA (2.88%) 로 관찰되었다. 추출 용매 별 항산화 활성은 농도(0.2, 0.4, 0.6 mg/mL)가 증가 할수록 유의적으로 증가하였으며 control로 사용된 ascorbic acid, BHA, trolox 보다는 낮은 활성이 확 인되었다. 치자 껍질의 total phenol 함량은 EA, 70% methanol, DW 추출물 순으로 EA 추출물에서 26.59±0.20 CAE (caffeic acid equivalents) mg/g으로 가장 높았으며, Nitric oxide (NO) radical 소거 능에서는 70% methanol (70.32~76.15%), DW (52.66~59.31%), EA (34.65~46.98%) 추출물 순으로 나타났다. Nitrite (NO2) 소거능은 70% methanol (34.57~39.33%), DW (32.53~38.47%), EA (27.59~32.62%) 순으로 관찰되었다. β-carotene 탈색 저해능은 DW (41.55~50.97%), 70% methanol (23.37~44.80%), EA (13.37~25.24%) 순으로 동정되었다. Reducing power (optical density)는 70% methanol (0.044~0.127), DW (0.033~0.099), EA (0.026~0.097) 순으로 확인되었다. 지질과산화 저해 능은 껍질 추출물 중 70% methanol (56.51~76.21%), EA (54.59~63.34%), DW (47.92~61.11%) 순 으로 관찰되었다(p<0.05). 이에, 치자 껍질은 기능성 식품 및 천연 항산화제로서의 가치가 매우 높을 것 으로 판단된다.
        4,000원