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.

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.

This study was conducted to investigate the effect of dietary sericite(SC) on laying performance, feed conversion ratio, egg quality and fecal ammonium nitrogen. Three hundreds and sixty 92-wk-old, Lohman Lite layers were randomly divided into 20 groups of 18 birds each and assigned to five experiment for 4 weeks (72 birds per treatment). Dietary treatments were Control (control diet), SC 0.5 (control diet +0.5% sericite), SC 1.0 (control diet +1.0% sericite), SC 1.5 (control diet +1.5% sericite), and SC 2.0 (control diet +2.0% sericite). Hen-day egg production tended to increase by the SC 1.0%, SC 1.5% and SC 2.0% supplementation in the diets. Egg weight also tended to increase by the SC 1.0% addition in the diets. Feed intake was increased (p<0.05) in SC 1.5 and SC 2.0 but feed conversion was improved (p<0.05) only in SC 1.0 (p<0.05). Digestibility of nutrients were not linearly affected by dietary supplementation of sericite although there was an inconsistent difference. Egg shell strength, albumin height, yolk color, and egg shell thickness were not affected (p<0.05) by treatments. Fecal NH3-N concentration was decreased (p<0.05) by dietary sericite supplementation compared to control. This study showed that dietary 1.0% sericite supplementation can be beneficial to improve egg production, egg weight and feed conversion and to decrease fecal NH3-N concentration.

암모니아성 질소는 생활하수, 축산폐수, 산업폐수 등의 점오염원과 화학적 비료 남용에 의한 유출 등의 비점오염원으로부터 수계로 방류되어 부영양화 등의 수질 오염을 유발할 수 있다. 생활하수 등에서 암모니아성 질소를 제거하기 위해 생물학적 처리공정이 주로 적용되고 있으나 운영상의 어려움, 비점오염원 저감의 어려움으로 인하여 대체방안이 요구된다. 바이오차를 흡착제로 활용하는 방안은 적용이 간단하며 효율적으로 수중 암모니아를 제거하는 방안으로 주목받고 있다. 선행 연구에서는 대부분 암모니아성 질소 흡착을 NH4+ 양이온 흡착으로 설명하고 있으나 수중의 암모니아성 질소는 pH에 따라 NH4+와 NH3(aq)로 분배될 수 있어 적용 조건에 따라 두 화학종이 모두 흡착에 참여할 가능성이 있다. 따라서 본 연구에서는 이러한 화학종 분배를 함께 고려하는 것의 필요성을 검증하고자 하였다. 바이오차는 발생량이 많은 농업부산물인 볏짚을 300, 400, 500, 600℃ 네 가지 최고온도로 열분해하여 얻었다. 암모니아성 질소 용액은 NH4Cl을 이용하여 준비하였다. 이후 20℃에서 바이오차 투여량 5 g/L 조건으로 초기농도 10 ~ 500 mg/L 용액에 대하여 등온흡착실험을 진행하였다. 흡착반응속도실험은 20℃에서 투여량 5 g/L 조건으로 초기농도 50 mg/L에서 진행하였다. 바이오차 투여 이후 pH는 NH4+의 pKa인 9.25 부근까지 증가하여 NH3(aq)가 액상에 존재할 수 있음을 확인하였다. 등온흡착곡선은 BET 모형에 의해 설명되었기에 응축에 의한 다층 흡착이 진행되는 것을 확인하였다. NH4+만이 흡착에 참여할 경우 쿨롱 반발력에 의해 응축이 일어날 수 없다. NH3(aq)가 흡착에 참여한다면 극성 분자의 쌍극자모멘트 또는 약한 수소결합으로 부터 응축에 의한 다층 흡착을 설명할 수 있다. 반응속도 실험결과 300℃에서 제조한 바이오차에 의한 암모니아성 질소 흡착은 유사 1차 반응속도 모형으로부터 설명할 수 있어 NH4+ 흡착이 주요한 것으로 생각된다. 300℃보다 높은 온도에서 제조한 바이오차의 경우 Elovich’s Equation이 암모니아성 질소의 흡착반응속도를 더 잘 설명하여 흡착 메커니즘을 NH4+ 흡착으로 설명할 수 없었다. Elovich’s Equation은 분자 상 물질의 화학적 흡착을 설명하는 모형이므로 NH3(aq)이 흡착에 참여하는 것으로 해석할 수 있다. 따라서 본 연구에서는 바이오차에 의한 암모니아성 질소 흡착은 NH4+ 이온의 흡착뿐만 아니라 NH3(aq)의 흡착도 함께 고려해야 함을 확인하였다.

겨울철에 금강하류에서는 암모니아성 질소(NH3-N) 농도가 주기적으로 높게 검출되어, 부여지점에서 취수하는 정수장의 수처리 공정에 큰 장애가 되고 있다. 질소농도 저하와 소독부산물 생성 억제를 위해 종종 대청댐의 추가 방류가 검토되고 있으나, 방류량과 직소농도 관계의 정량적 분석에 어려움이 있었다. 본 연구에서는 8년간의 일별 수질자료와 댐 방류량 자료를 이용하여 겨울철(12월∼3월) 동안 일별 NH3-N 농도를 예측할 수 있는 다중회귀모형을 개발하고,

Nitrifier consortium immobilized in polyvinyl alcohol was used for the removal of ammonia nitrogen from synthetic aquaculture water in the airlift bioreactor. At the aeration rate of 0.15 vvm and bead packing volume fraction of 20%, airlift bioreactor was operated effectively for a removal of ammonia nitrogen and for a stability of operation. Ammonia nitrogen removal rate by airlift bioreactor was continuously increased with decreasing hydraulic residence time. At the HRT(hydraulic residence time) of 0.3 hour, ammonia nitrogen removal rate was 84.3 g/㎥·d and the highest ammonia nitrogen removal rate was 130.8 g/㎥·d when HRT was 0.1 hour.