검색결과

검색조건
좁혀보기
검색필터
결과 내 재검색

간행물

    분야

      발행연도

      -

        검색결과 45

        1.
        2023.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 소맥 위주 사료에 xylanase 효소제의 첨가가 육성돈의 사양성적, 영양소 소화율, 혈액성상, 분 중 휘발 성 지방산 및 암모니아성 질소 농도에 미치는 영향을 알 아보기 위하여 실시하였다. 총 192두(4처리, 8반복, 반복당 6두)의 육성돈(25.14±0.11 kg)을 공시하여 xylanase 첨가수 준(0, 0.0125, 0.025, 0.0375%)으로 6주간 사양시험을 실시 하였다. xylanase의 첨가수준이 증가함에 따라 전체 사양 구간에서의 일당증체량(ADG), 일일사료섭취량(ADFI) 및 사료요구율(FCR)이 유의적으로 개선되는 효과를 나타냈 다(p<005). 영양소 소화율에 있어서, xylanase 첨가수준이 증가함에 따라 phase Ⅰ에서는 건물 및 에너지, phase Ⅱ 에서는 조단백질 소화율이 유의적으로 개선되었으며, 또 한 육성돈의 혈중 GLU 농도는 사료 내 xylanase의 첨가 수준이 증가함에 따라 유의적으로 증가하는 효과를 보였 다(p<0.05). 반면에, 휘발성 지방산 및 암모니아성 질소 농 도에서 xylanase의 유의적인 첨가효과는 나타나지 않았다 (p>0.05). 결론적으로, 소맥 위주의 사료 내 xylanase의 첨 가는 육성돈의 사양성적, 영양소 소화율 및 혈중 GLU 농 도를 증가시키는데 긍정적인 효과를 보였으며, 육성돈 사 료내 소맥을 주원료로 사용할 경우 xylanse의 적정 첨가 수준은 0.0375%으로 사료된다.
        4,000원
        2.
        2022.10 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        We report the synthesis and gas sensing properties of bare and ZnO decorated TeO2 nanowires (NWs). A catalyst assisted-vapor-liquid-solid (VLS) growth method was used to synthesize TeO2 NWs and ZnO decoration was performed using an Au-catalyst assisted-VLS growth method followed by a subsequent heat treatment. Structural and morphological analyses using X-ray diffraction (XRD) and scanning/transmission electron microscopies, respectively, demonstrated the formation of bare and ZnO decorated TeO2 NWs with desired phase and morphology. NO2 gas sensing studies were performed at different temperatures ranging from 50 to 400 oC towards 50 ppm NO2 gas. The results obtained showed that both sensors had their best optimal sensing temperature at 350 oC, while ZnO decorated TeO2 NWs sensor showed much better sensitivity towards NO2 relative to a bare TeO2 NWs gas sensor. The reason for the enhanced sensing performance of the ZnO decorated TeO2 NWs sensor was attributed to the formation of ZnO (n)/ TeO2 (p) heterojunctions and the high intrinsic gas sensing properties of ZnO.
        4,000원
        3.
        2022.09 KCI 등재 구독 인증기관 무료, 개인회원 유료
        Excess nitrogen (N) flowing from livestock manure to water systems poses a serious threat to the natural environment. Thus, livestock wastewater management has recently drawn attention to this related field. This study first attempted to obtain the optimal conditions for the further volatilization of NH3 gas generated from pig wastewater by adjusting the amount of injected magnesia (MgO). At 0.8 wt.% of MgO (by pig wastewater weight), the volatility rate of NH3 increased to 75.5% after a day of aeration compared to untreated samples (pig wastewater itself). This phenomenon was attributed to increases in the pH of pig wastewater as MgO dissolved in it, increasing the volatilization efficiency of NH3. The initial pH of pig wastewater was 8.4, and the pH was 9.2 when MgO was added up to 0.8 wt.%. Second, the residual ammonia nitrogen (NH4 +-N) in pig wastewater was removed by precipitation in the form of struvite (NH4MgPO4·6H2O) by adjusting the pH after adding MgO and H3PO4. Struvite produced in the pig wastewater was identified by field emission scanning electron microscopy (FE-SEM) and X-ray diffraction (XRD) analysis. White precipitates began to form at pH 6, and the higher the pH, the lower the concentration of NH4 +-N in pig wastewater. Of the total 86.1% of NH4 +-N removed, 62.4% was achieved at pH 6, which was the highest removal rate. Furthermore, how struvite changes with pH was investigated. Under conditions of pH 11 or higher, the synthesized struvite was completely decomposed. The yield of struvite in the precipitate was determined to be between 68% and 84% through a variety of analyses.
        4,000원
        4.
        2021.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        MMBR system has been suggested as a promising system to resolve harvesting problems induced from low settling efficiency of microalgae. And recently, a lot of research on reducing fouling at the MMBR system has investigated focused on EPS in many cases. EPS of microalgae mainly consists of polysaccharides and protein components, and is produced through photosynthesis and nitrogen-carbon metabolic pathways. Especially, P-EPS is one of major compounds which occur membrane fouling phenomenon, as its hydrophobic protein components cause floc formation and cake layer accumulation. And it is already known that almost every microalgae can metabolize P-EPS or Chl-a when nitrogen sources as a substrate is insufficient or exhausted situation. With the above backgrounds, uptake rates of P-EPS or Chl-a by Scenedesmus quadricauda according to the type of carbon source and nitrogen concentration were evaluated in order to verify correlation between carbon source vs P-EPS production, and indeed Scenedesmus quadricauda uses P-EPS or Chl-a when the amounts of nitrogen sourc es in the feed is not satisfied. As a result, it was shown that P-EPS and Chl-a production were increased proportional to nitrogen concentration under organic carbon condition. And especially, the amo unts of P-EPS and Chl-a in the cell were diminished with the nitrogen source becomes insufficient or exhausted. Because P-EPS accelerates fouling at the MMBR system, P-EPS degradation by Scenedesmus quadricauda in order to get nitrogen source may contribute to reducing fouling. About a affects of N-consumed Chl-a to the MMBR fouling, more survey is needed. On the contrary, considering the purpose of MMBR system of this study, i.e. harvesting useful high value microalgae efficiently feeding adequate industrial process wastewater, it seems like difficult to maintain satisfied metabolic activity and to harvest with high yield rate using nitrogen-poor MMBR feed.
        4,200원
        5.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : This study analyzes the characteristics of nitrogen oxide concentration by applying titanium dioxide to existing roads in urban areas, using correlation analysis and a generalized linear model. METHODS : To analyze the characteristics of nitrogen oxide concentration with/without applying titanium dioxide to the urban road segment, data acquisition was conducted for nitrogen oxide concentration, weather information, and traffic information, etc., and a correlation analysis was conducted for each factor, with/without applying titanium dioxide to the roads. In addition, nitrogen oxide concentration generation models with/without the application of titanium dioxide to the roads were estimated using a generalized linear model. RESULTS : The results demonstrate that relative humidity and temperature were found to be slightly correlated with the nitrogen oxide concentration, both with and without the application of titanium dioxide to the roads; however, wind speed, solar radiation, and traffic volume were found to have somewhat low correlation according to the results of a correlation analysis. Moreover, relative humidity, temperature, solar radiation, and traffic volume were significant when titanium dioxide was applied to the roads, based on the estimated model from a generalized linear model, and the wind speed, solar radiation, and traffic volume were significant for the absence of titanium dioxide on the roads. CONCLUSIONS : Analytical results indicated that the characteristics of nitrogen oxide concentration vary depending on the application of titanium dioxide to the roads. In particular, when titanium dioxide was applied to the roads, the relative humidity and temperature were analyzed; according to both analyses, i.e., correlation analysis and a generalized linear model, the nitrogen oxide concentration was affected.
        4,000원
        6.
        2020.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : The objective of this study is to determine the characteristics of nitrogen oxide (NOx) concentration in an exclusive median bus lane station. The hourly variations of NOx concentration and the effect of traffic volume on NOx concentration were analyzed using NOx measurement data and the number of vehicles at the station. METHODS : Data were collected using the chemiluminescence method for NOx concentration. Atmospheric information and traffic volume of buses were collected from the Korea Meteorological Administration and Bus Information System, respectively. RESULTS : As a result, the NO2 concentration in the test section was found to have a strong correlation with those in the atmospheric measurement station located near the test-bed. In addition, the average NOx concentrations in the test section were significantly higher than those of the other monitoring stations due to bus emissions. The average NOx concentration in the exit section was higher than that in the entry section owing to the vehicle’s frequent stops and fuel consumption due to acceleration. During the measurement period, the average NOx concentration was measured as approximately 33 % higher in the exit section than in the entry section. In addition, the NOx concentration at the bus station was found to increase as the bus dwell time increased, rather than the number of bus passages. CONCLUSIONS : This study provides clear characteristics of the NOx correlations with traffic information in an exclusive median bus lane station. It was shown that the NOx concentration at the bus station increased as the number of passes and bus dwell time increased. According to the coefficient of determination, the dwell time is more closely correlated to the NOx concentration at the bus station than the number of bus passes, indicating that it is a better parameter for predicting NOx concentration at bus stations.
        4,000원
        7.
        2020.08 KCI 등재 구독 인증기관 무료, 개인회원 유료
        PURPOSES : This study analyzes the characteristics of generated fine particulate matter (PM2.5) and nitrogen oxide (NOX) at roadsides using a statistical method, namely, a generalized linear model (GLM). The study also investigates the applicability and capability of a machine learning methods such as a generalized regression neural network (GRNN) for predicting PM2.5 and NOX generations. METHODS : To analyze the characteristics of PM2.5 and NOX generations at roadsides, data acquisition was conducted in a specific segment of roads, and PM2.5 and NOX prediction models were estimated using GLM. In addition, to investigate the applicability and capability of a machine learning methods, PM2.5 and NOX prediction models were estimated using a GRNN and were compared with models employing previously estimated GLMs using r-square, mean absolute deviation (MAD), mean absolute percentage error (MAPE), and root mean square error (RMSE) as parameters. RESULTS : Results revealed that relative humidity, wind speed, and traffic volume were significant for both PM2.5 and NOX prediction models based on estimated models from a GLM. In addition, to compare the applicability and capability of the GLM and GRNN models (i.e., PM2.5 and NOX prediction models), the GRNN model of PM2.5 and NOX prediction was found to yield better statistical significance for r-square, MAD, MAPE, and RMSE as compared with the same parameters used in the GLM. CONCLUSIONS : Analytical results indicated that a higher relative humidity and traffic volume could lead to higher PM2.5 and NOX concentrations. By contrast, lower wind speed could affect higher PM2.5 and NOX concentrations at roadsides. In addition, based on a comparison of two statistical methods (i.e., GLM and GRNN models used to estimate PM2.5 and NOX), GRNN model yielded better statistical significance as compared with GLM.
        4,000원
        8.
        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
        9.
        2017.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 겨울철 파프리카의 안정된 영양생장, 생식 생장을 파악하는 방법으로 간이영양진단기기를 이용해 NO3 - 농도를 신속하게 측정하고 영양상태 파악을 위해 실시되었다. ‘Raon red’, ‘Raon yellow’ 두 품종을 각각 비대기 단계로 나누어 측정한 결과 엽신의 test strip 분 석은 분광광도계를 통한 관행의 방법과 상관성이 인정되었고(R2=0.8628), 엽병의 test strip분석은 엽신 즙액 보다는 낮은 상관성을 보이지만 간접적으로 NO3 - 농도 분석에 유용하였다(R2=0.6734). 착과 그룹이 높아짐에 따라 해당 부위 엽 내 질산태질소 농도가 낮아지는 경향을 보이고 있으며, 동일 시점의 마디별 엽병 즙액 내 질산태질소 농도 역시 정단부로 갈수록 낮아지는 경향이 확인되었다. 엽병 즙액 내 NO3 - 농도 역시 간이진단기기를 활용하여 신속한 모니터링이 가능하였다. 따라서 간이영양진단기기를 사용해 기존 분석방법보다 효과적으로 농가 현장에서 파프리카의 질소 영양상태를 파악할 수 있었으며, 이를 통해 추후 합리적인 양액공급 및 표준영 양범위의 설정이 가능할 것으로 판단된다.
        4,000원
        10.
        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
        11.
        2016.02 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This paper presents the applicability of natural zeolite (Clinoptilolite) for recovery of ammonium nitrogen from high-strength wastewater stream. Isotherm experiments showed the ammonium exchange Clinoptilolite followed Freundlich isotherm and its maximum exchange capacity was 18.13 mg NH4+-N/g zeolite. The X-ray photoelectron spectroscopy (XPS) analysis indicated that a significant amount of nitrogen was adsorbed to the Clinoptilolite. Optimal flowrate for recovery of high concentration ammonium nitrogen was determined at 16 BV/d (=19.2 L/min) throughout the lab-scale column studies operated under various flowrate conditions. This study also provided a method to determine the recovery rate of final product of nitrogen fertilizer based on the model application to the lab-scale continuous data.
        4,000원
        12.
        2015.10 구독 인증기관·개인회원 무료
        본 연구는 지구온난화와 식물 생장의 제한요소로 알려져 있는 질소가 단양쑥부쟁이의 생육에 어떤 영향을 미치는지 알아보기 위해 지구온난화 조건하에서 질소의 농도를 다르 게 처리하여 생육시킨 후 그 결과를 비교하였다. 이를 위하 여 온실을 두 구획으로 나누고, 한 곳은 CO2를 처리하지 않은 대조구로, 다른 한 곳은 CO2를 처리한 처리구로 설정 하였다. 대조구는 대기 중 CO2 농도와 온도를 그대로 반영 하였고, 처리구는 대조구보다 CO2 농도와 온도를 더 높게 상승시켰다. 그 후, 대조구와 처리구 내에서 각각 개체수(1, 2, 3 개체)와 질소량(0, 2, 20g)을 다르게 처리하여 지상부, 잎 폭 그리고 잎 길이에 차이를 비교하였다. 그 결과 개체수 가 하나 이거나 두 개일때, 대조구와 처리구 모두 질소량이 증가할 수록 줄기길이, 잎 길이 그리고 잎 폭 모두 좁아졌다. 개체수가 세 개일 때, 질소량이 증가할 수록 대조구는 줄기 길이가 낮아졌고, 처리구는 줄기길이, 잎 길이 그리고 잎 폭 모두 짧아졌다. 일반적으로 단양쑥부쟁이는 하천변에서 군락을 이루어 서식하는 것으로 알려져 있는데, 이 결과는 지구온난화는 거의 영향이 없고, 하천 오염이 심해질 경우 단양쑥부쟁이의 생육에 피해를 입힐 수 있을 것으로 판단된 다.
        13.
        2013.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 염생식물인 퉁퉁마디를 대상으로 하여 신간척지에서 안정적인 재배법을 구명하고자 수행하였다. 먼저 퉁퉁마디의 발아특성을 알아보기 위해 염농도(NaCl 0 ~ 3% 농도) 별발아율 시험을 수행하였다. 10oC에서는 모든 염농도에서 발아속도는 느리나 15일까지 발아가 지속되어, 78 ~ 90%의 발아율을 나타내었다. 20oC이상에서는 4일 안에 최대의 발아율을 나타내었으며, NaCl 3%에서 온도가 올라갈수록 발아율이 저하되는 경향을 보였다. 퉁퉁마디의 질소시비량 별 생육특성을 알아보기 위해 온실포트실험을 실시한 결과, 퉁퉁마디 파종 후 5일 후부터 발아가 시작하였고, 퉁퉁마디의 생육은 질소시비량이 증가할수록초장 및 분지 등이 증가하는 경향을 나타내었다. 또한 염농도에 따른 생육특성을 조사하기 위해 양액 재배 조건에서 염농도에 따른 퉁퉁마디 생육을 실험하였다. 양액조건 상태에서NaCl을 처리하지 않으면 생육이 저조하여 1개월 이후에 고사하기 시작했으며, NaCl을 처리한 구에서는 NaCl 200 mM에서생육이 좋았고, NaCl 500 mM 이상의 염농도에서도 재배가 가능할 것이라 생각된다. 신간척지에서 퉁퉁마디의 어린 싹을6월에 이식하여 질소시비량이 퉁퉁마디 생육에 미치는 영향을조사하였다. 퉁퉁마디의 초장 및 분지수 등이 질소시비량이 증가할수록 유의적으로 증가하였으나, 인산을 비롯한 무기성분함량은 유의적인 차이가 없었다.
        4,000원
        14.
        2012.06 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        This study conducted comparison and data analysis of evaluation results from three kinds of monitoring methods for indoor air quality monitoring, which are Korean Official test method for indoor air quality, monitoring method by gas analyzer, and continuous measurement by using sensor. NO2, one of indoor air pollutants, was selected as a evaluation factor for this study because it is commonly generated during the operation of potable gas range. Monitoring results of NO2 concentration from three subjected methods show that background concentration of NO2, before operation of portable gas range, was 43.05~50.22ppb. On the other hand, NO2 concentration for four and half hours (4½) after gas range operation was 64.31~69.89ppb in average. Average concentration of NO2 during first thirty (30) minutes was increased about 33.85~49.39% than the concentration of NO2 before operation of gas range. </br>In general, monitoring results by utilizing NO2 gas analyzer was 8.1% higher than the results by continuous measurement using sensor method. In case of monitoring method using sensor, the results was lower about 6.1% than Korean official test method, and lower about 11.7~3.2% than NO2 gas analyzer. Especially, change rate of concentration for first thirty (30) minutes measured by Korean official test method was 50ppb/hr, which is 44.4% lower than the change rate from NO2 gas analyzer, 90ppb/hr, and 43.2% lower than results from sensor, 88ppb/hr. </br>In accordance with this study, it is concluded that monitoring frequency for indoor air quality management must be shorten during the time period having significant change rate of NO2 concentration. In other words, air quality monitoring must be considered characteristics of concentration changes as well as accuracy of measurement.
        4,500원
        15.
        2011.03 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        In this study, we estimated nitrogen dioxide (NO2) concentrations in microenvironments where residential indoor, residential outdoor, other indoors, and transportation using measured personal exposure and multiple linear regression analysis of time-weighted average model, and compared with measured NO2 concentration in microenvironments. Measured residential indoor, outdoor and other indoor NO2 concentration was 22.22±9.59 ppb, 23.64±9.62 ppb, and 22.07±13.90 ppb, respectively. NO2 concentrations in residential indoor and outdoor, total outdoor, other indoor, and transportation by multiple regression analysis were significantly estimated as 20.48 ppb, 32.79 ppb, 24.35 ppb, and 28.82 ppb, respectively (p= 0.000). Measured and estimated NO2 concentration were similar with each other, therefore NO2 concentrations in each microenvironment were able to be estimated using time-weighted average model and personal exposure with multiple regression analysis.
        4,000원
        16.
        2010.12 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        This study presents residential indoor and outdoor exposure concentrations distributions of volatile organic compounds (VOCs, benzene, toluene, xylene) and nitrogen dioxide (NO2) in industrial area (case) and agricultural area (control) during 5 days. Concentrations of VOCs and NO2 were measured with passive samplers in residential indoor and outdoor. Most of benzene, toluene and NO2 mean concentrations in case area were higher than those in control area. Considering the indoor and outdoor ratios (I/O) were higher than 1, the residence might be have the sources of indoor air pollutants such as smoking and using of gas range. Residential indoor concentrations of benzene, toluene, and NO2 with indoor smokers were higher than those and without indoor smokers. In conclusion, it is suggested that personal exposures to air pollutants might be affected by indoor sources as well as outdoor pollutants emitted from industrial complex, and indoor air quality and outdoor air quality should be simultaneously considered to reduce the personal exposure to air pollutants.
        4,200원
        17.
        2009.06 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구에서는 공업용수 중에 미량 함유될 수 있는 철 이온 제거를 위해 철 용액에 음이온 계면활성제 SDS를 주입하여 미셀을 형성한 후, 미셀 표면에 철 이온의 흡착 또는 결합으로 형성된 응집체를 관형 세라믹 정밀여과막으로 제거하였다. 음이온 계면활성제의 영향을 살펴보기 위해 일정한 1mM의 철 농도에서 음이온 계면활성제의 농도를 0~10 mM로 변화시켰다. 그 결과, 6mM 일 때 가장 높은 철 제거율 88.97%를 보였다. SDS 농도에 따른 미셀 응집체의 입도 분포를 확인하기 위해 전기영동광산란분광광도계(Electrophoretic Light Scattering Spectrometer)를 사용하여 분석 한 결과, 6mM 일때 큰 응집체의 분포도가 가장 높았다. 또한, 세라믹 분리막에 대하여 주기적 질소 역세척을 실시할 경우 역세척 주기의 영향을 조사하였다. 그 결과, NCMT-7231 (평균기공 0.10μm) 분리막의 최적 역세척 시간(BT)는 20초이었다.
        4,000원
        18.
        2009.03 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        Exposure to nitrogen dioxide (NO2) can produce adverse health effects. Various indoor and outdoor combustion sources make NO2 the most ubiquitous pollutant in the indoor environment. Indoor air quality can be affected by indoor sources, ventilation, decay and outdoor levels. Although technologies exist to measure these factors, direct measurements are often difficult. In the present paper, we used a mass balance model and regression analysis, penetration factor (ventilation rate divided by the sum of ventilation rate and deposition constant) and source strength factor (source strength divided by the sum of ventilation rate and deposition constant) were calculated using multiple indoor and outdoor measurements with 10 houses. Subsequently, mean contributions of indoor and outdoor sources were 28.86% and 81.09%, respectively, suggesting that both indoor and outdoor sources had contributions to indoor concentrations of NO2.
        4,000원
        19.
        2008.10 구독 인증기관·개인회원 무료
        본 연구는 제품 생산과정 시 해충혼입에 의한 소비자 해충 클레임 발생 가능성을 규명하고자 고농도 질소충진(98.6~98.8%) 유아용 캔 포장 분유제품에서의 화랑곡나방 알, 유충(4령)의 발육 가능성을 알아보았다. 고농도 질소가스와 일반 대기로 포장된 제품내부에서 보관기간에 따라 부화율, 우화율, 치사율 등을 조사하였고 포장해체 후 지속적으로 보관하면서 동일한 조사를 수행하였다. 실험 결과 질소충진 처리하였을 경우 보관기간에 관계없이 화랑곡나방 알과 유충은 100% 치사하였다. 그러나 질소가 충진되지 않은 처리구에서 유충 치사율은 대략 40%정도를 나타내었고, 보관 기간에 따라 유의한 차이는 보이지 않았다(df=2,27, F=2.06, P>0.05). 화랑곡나방 알의 경우 모든 반복에서 실크가 발견되어 부화가 이루어졌으나, 발육이 지속적으로 진행되었을 경우 발견되었을 것으로 예상되는 2~3령 유충이 발견되지 않아 분유제품이 갓 부화한 1령 유충의 먹이로는 적합하지 않은 것으로 조사되었다.
        20.
        2007.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구는 질소의 시비농도를 인위적으로 조절하여 잎들깨를 관비재배 하면서 질소의 시비수준이 생장과 결핍증상 발현에 미치는 영향을 구명하고, 생육을 우수하게 유지할 수 있는 식물체 및 토양의 한계농도를 밝히기 위하여 수행하였다. 질소 무시비구에서 지상부 식물생육의 심한 억제 현상과 노엽의 엽신 전체가 황화된 후 점차 괴사하는 결핍증상이 나타났다. 질소 시비농도가 높아질수록 정식 75일 후의 생체중과 건물중이 무거워졌고, 엽병 추출액의 NO3-N 농도와 토양 NO3-N 농도가 높아졌으나, 20mM 시비구에서는 질소과잉증상이 나타났다. 10~15mM 시비구에서 가장 바람직한 생장을 보였으며, 이때의 질소 함량은 건물중 기준으로 0.9~1.25%, 엽병추출액 및 1:2 추출법으로 분석한 토양의 NO3-N 농도가 각각 800~3,300mg·kg-1 및 28.7~47.3mg·L-1 범위에 포함되었다.
        4,000원
        1 2 3