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        검색결과 10

        1.
        2021.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        국내 고농도의 초미세먼지 발생 빈도 증가와 함께 그 전구물질인 NH3와 관련한 연구가 활발히 진행 중이다. NH3 배출에 있어 농업의 기여율이 높은 것은 자명한 사실이다. 그러나 비료 사용이 농경지 대기 중 NH3 농도에 장기간 미치는 영향에 관련한 연구는 미비한 실정이다. 따라서 본 연구에서는 수동식 NH3 확산형 포집기를 활용해 11개월 간 농경지 대기 중 NH3 농도를 관측하였다. 그 결과 비료 살포 직후 한 달 동안 NH3 배출의 영향이 가장 큰 것으로 나타났다. 그 이후 여름철 기온 상승으로 NH3 휘발이 촉진되어 대기 중 농도가 증가할 것으로 예상하였으나, 54일간의 지속적인 강우로 인하여 대기 중 높은 암모니아 농도는 관측되지 않았다. 그 후 NH3 농도는 가을과 겨울을 거치면서 점차 감소하였다. 비료의 영향력이 감쇠한 시점 이후에는 기온이 감소할수록, 그리고 강수량이 증가할수록 NH3 농도는 감소하는 것을 상관분석을 통해 확인할 수 있었다. 종합해 보면, 국내 NH3 배출량에서 비료의 기여율을 연구하는 데 있어 비료 살포 직후 최소 한 달 동안은 집중적으로 살펴보아야 할 것이며, 현장 연구 시 강수량과 무강우 일수 등의 기상 정보도 함께 고려해야 할 것이다.
        4,000원
        2.
        2021.03 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This ammonia prediction study was performed using the time-series artificial neural network model, Long-short term memory (LSTM), after long-term monitoring of ammonia and environmental factors (ventilation rate (V), temperature (T), humidity (RH)) from a slurry finishing pig farm on mechanical ventilation system. The difference with the actual ammonia concentration was compared through prediction of the last three days of the entire breeding period. As a result of the analysis, the model which had a low correlation (ammonia concentration and humidity) was confirmed to have less error values than the models that did not. In addition, the combination of two or more input values [V, RH] and [T, V, RH] showed the lowest error value. In this study, the sustainability period of the model trained by multivariate input values was analyzed for about two days. In addition, [T, V, RH] showed the highest predictive performance with regard to the actual time of the occurrence of peak concentration compared to other models . These results can be useful in providing highly reliable information to livestock farmers regarding the management of concentrations through artificial neural network-based prediction models.
        4,000원
        3.
        2020.11 KCI 등재 SCOPUS 구독 인증기관 무료, 개인회원 유료
        Due to the serious air pollution problem, interest in eco-friendly vehicles is increasing. Solving the problem of pollution will necessitate the securing of high energy storage technology for batteries, the driving force of eco-friendly vehicles. The reason for the continuing interest in the transition metal oxide LiMO2 as a cathode material with a layered structure is that lithium ions reveal high mobility in two-dimensional space. Therefore, it is important to investigate the effective intercalation and deintercalation pathways of Li+, which affect battery capacity, to understand the internal structure of the cathode particle and its effect on the electrochemical performance. In this study, for the cathode material, high nickel Ni0.8Co0.1Mn0.1(OH)2 precursor is synthesized by controlling the ammonia concentration. Thereafter, the shape of the primary particles of the precursor is investigated through SEM analysis; X-ray diffraction analysis is also performed. The electrochemical properties of LiNi0.8Co0.1Mn0.1O2 are evaluated after heat treatment.
        4,000원
        4.
        2016.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        This study investigated the effect of high concentration of free ammonia on microalgal growth and substrate removal by applying real wastewater nitrogen ratio. To test of this, the conditions of free ammonia 1, 3, 6, 9, 12, 15 mg-N/L are compared. After 3 days of incubation, algal growth of Chlorella vulgaris and carbon removal rate are respectively lower in the reactors of FA 12, 15 mg-N/L compared to the others. This indicates that the high concentration of free ammonia, in this case, above 12 mg-N/L, has negative effect on algal growth and metabolic activity. Also, high concentration of free ammonia causes the proton imbalance, ammonium accumulation in algae and has toxicity for these reasons. So, we have to consider free ammonia in applying the microalgae to wastewater treatment system by the way of diluting wastewater or controlling pH and temperature.
        4,000원
        5.
        2014.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        It is essential to decrease energy consumption and excess sludge to economically operate sewage treatment plant. This becomes more important along with a ban on sea dumping and exhaustion of resource. Therefore, many researchers have been study on energy consumption reduction and strategies for minimization of excess sludge production from the activated sludge process. The aeration cost account for a high proportion of maintenance cost because sufficient air is necessary to keep nitrifying bacteria activity of which the oxygen affinity is inferior to that of heterotrophic bacteria. Also, additional costs are incurred to stabilize excess sludge and decrease the volume of sludge. There were anoxic, aerobic, membrane, deairation and concentration zone in this MBR process. Continuous aeration was provided to prevent membrane fouling in membrane zone and intermittent aeration was provided in aerobic zone through ammonia sensor. So, there was the minimum oxygen to remove NH4-N below limited quantity that could be eliminated in membrane zone. As the result of this control, energy consumption of aeration system declined by between 10.4 % and 19.1 %. Besides, we could maintain high MLSS concentration in concentration zone and this induced the microorganisms to be in starved condition. Consequentially, the amount of excess sludge decrease by about 15 %.
        4,000원
        6.
        2012.04 KCI 등재 구독 인증기관 무료, 개인회원 유료
        본 연구의 목적은 강제환기가 적용되는 슬러리 돈사를 대상으로 돼지 생육 단계별 돈방 유형 측면과 계절적 조건에 따른 암모니아와 황화수소의 실내 농도를 측정 분석하여 정량화하는 데 있다. 임신/분만 돈방의 경우 봄철은 5.60(±2.48) ppm과 178.4(±204.8) ppb, 여름철은 2.51(±3.08) ppm과 86.6(±112.5) ppb, 가을철은 4.96(±2.84) ppm과 182.3(±242.6) ppb, 겨울철은 6.82(±3.42) ppm과 206.3(±356.8) ppb로, 자돈방의 경우 봄철은 7.18(±3.26) ppm과 486.0(±190.2) ppb, 여름철은 4.23(±2.95) ppm과 206.4(±186.9) ppb, 가을철은 7.02(±2.65) ppm과 465.4(±156.8) ppb, 겨울철 은 9.25(±3.68) ppm과 618.4(±298.3) ppb로, 육성/비육 돈방의 경우 봄철은 9.26(±3.02) ppm과 604.4(±186.8) ppb, 여름철은 6.78(±3.88) ppm과 312.5(±215.4) ppb, 가을철은 9.34(±2.14) ppm과 578.2(±248.1) ppb, 겨울철은 14.65(±3.15) ppm과 825.3(±316.9) ppb로 분석되었다. 측정 결과 암모니아와 황화수소 모두 돼지 생육 단계별 돈사 유형 측면에서는 육성/비육 돈사>자돈사>임신/분만 돈사의 순서로 나타났고(p<0.05), 계절적 측면에서는 겨울>봄>가을>여름 순서로 조사되었으나 봄철과 가을철 데이터 간의 차이는 통계적으로 입증되지 않았다(p>0.05).
        4,000원
        7.
        2010.12 KCI 등재후보 구독 인증기관 무료, 개인회원 유료
        The purpose of this study is to estimate concentration and emission unit of ammonia and hydrogen sulfide released from domestic chicken buildings by field investigation. Mean concentrations of ammonia and hydrogen sulfide emitted from chicken buildings were 18.25(±4.78)ppm and 807.53(±526.17)ppb for caged layer house, 14.48(±4.13)ppm and 644.82(±312.48)ppb for broiler house, and 6.16(±2.02)ppm and 284.75(±232.08)ppb for layer house with manure belt, respectively. Mean emission coefficients of ammonia and hydrogen sulfide were 0.951(±0.131) g hen-1h-1 and 2.956(±0.968) mg hen-1h-1 based on head whereas they were 0.575(±0.082) g m-2h-1 and 12.44(±3.536) mg m-2h-1 based on time. In conclusion indoor concentration and emission coefficient of ammonia and hydrogen sulfide were highest in caged layer housed, followed by broiler house and layer house with manure belt.
        4,000원
        8.
        2005.12 KCI 등재 구독 인증기관 무료, 개인회원 유료
        In order to investigate the effects of magnetized water treated with HI-Scalper153R on body performance and ammonia concentration in feces of broiler chicks, a feeding trial was conducted with a total of 180 broiler chicks. Each treatment had 18 chicks with 5 replications. Chicks during experimental periods, broiler chicks were fed magnetized water and subterranean water, respectively. The results obtained summarized as follows: Body weight gain slightly increased for broiler chicks fed magnetized water compared with control. But, there is no significantly (p=0.36) different among treatments. Feed intake significantly (p=0.046) decreased for broiler chicks fed magnetized water compared with control. Feed efficiency was significantly (p=0.020) improved for broiler chicks fed magnetized water of each periods when compare to the control. Especially, in starter periods, the feed efficiency of magnetized water treatment increased by 10% more than control (1.80 vs 1.69). In feces, average ammonia concentration (ppm) significantly (p=0.004) decreased in the magnetized water treatment compare to control. Especially, the magnetized water treatment decreased by 2.2 times compared to the control in ammonia concentration of feces (83 vs 37ppm).
        4,000원
        9.
        2005.03 구독 인증기관 무료, 개인회원 유료
        본 연구는 한우 수정란의 체외생산에 있어서 효율과 품질의 향상을 위해서, 체외성숙 시간에 따른 배지 내의 ammonia 농도를 측정하였고, 체외성숙용 배지의 교환 및 첨가가 배 발생과 배반포의 세포수에 미치는 효과를 검토하였다. 체외성숙용 배지내의 ammonia 농도는 체외성숙 시간이 길어짐에 따라 유의하게 증가하였다(p<0.05). 체외성숙용 배지의 첨가에 따른 수정율, 8세포기 및 배반포기 발달율은 각 군간에 유사한 경향이었다. 배반포의 inner cell mass(ICM) 및 총 세포수(TCN)는 비슷한 경향이었으나, trophectoderm(TE) 세포수는 4.5 시간 첨가군이 유의하게 낮았다. 한편 ICM/TCN 비율은 4.5 시간 첨가군이 대조군과 9 시간 첨가군에 비하여 유의하게 높았다. 체외성숙용 배지의 교환에 따른 수정율은 4.5시간 및 9시간 교환이 대조군에 비하여 유의하게 높았으나, 8세포기 발달율은 비슷한 경향이었다. 한편 배반포기 발달율은 9 시간 교환군이 가장 높았다. 배반포의 ICM 세포수와 ICM/TCN 비율은 9 시간 교환군이 다른 두 처리군에 비하여 유의하게 높았으나, TE 및 TCN은 차이가 없었다.
        4,000원