• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2006년도 춘계학술대회 논문집
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• pp.421-424
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• 2006

High nitrogen steels (HNS) exhibit both high strength and ductility during tensile deformation. In the present study the Fe-18Cr-14Mn-4Ni-0.9N high nitrogen steel was heat treated at $1000^{\circ}C$ and $1100^{\circ}C$ to produce $Cr_2N$ precipitates in austenite matrix and full austenite microstructures, respectively. Tensile tests of the heat treated specimens were performed at two different strain rates of 0.05/sec and 0.00005/sec. Each tensile curve of the specimens could be well characterized by the the modified Ludwik equation. Plastic deformation of the steel was adequately represented by the four parameters of the modified Ludwik equation. At 0.05/s strain rate, the specimen with the $Cr_2N$ precipitate exhibited higher strength than the full austenite specimen, while the full austenite specimen showed better mechanical properties at 0.00005/s strain rate. It was found that the $Cr_2N$ precipitates influences deformation behavior of the high nitrogen steel significantly.

• Membrane and Water Treatment
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• 제10권4호
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• pp.265-275
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• 2019

This study aimed to develop a compact partial nitritation step by forming granules with high Ammonia-Oxidizing Bacteria (AOB) fraction using the Air-lift Granulation Reactor (AGR) and to evaluate the feasibility of treating reject water with high ammonium content by combination with the Anammox process. The partial nitritation using AGR was achieved at high nitrogen loading rate ($2.25{\pm}0.05kg\;N\;m-3\;d^{-1}$). The important factors for successful partial nitritation at high nitrogen loading rate were relatively high pH (7.5~8), resulting in high free ammonia concentration ($1{\sim}10mg\;FA\;L^{-1}$) and highly enriched AOB granules accounting for 25% of the total bacteria population in the reactor. After the establishment of stable partial nitritation, an effluent $NO_2{^-}-N/NH_4{^+}-N$ ratio of $1.2{\pm}0.05$ was achieved, which was then fed into the Anammox reactor. A high nitrogen removal rate of $2.0k\; N\;m^{-3}\;d^{-1}$ was successfully achieved in the Anammox reactor. By controlling the nitrogen loading rate at the partial nitritation using AGR, the influent concentration ratio ($NO_2{^-}-N/NH_4{^+}-N=1.2{\pm}0.05$) required for the Anammox was controlled, thereby minimizing the inhibition effect of residual nitrite.

• 에너지공학
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• 제23권3호
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• pp.174-180
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• 2014

연속적으로 누출되는 극저온 액체의 풀 확산을 액체질소를 사용하여 실험적으로 연구하였다. 본 실험을 위해 Cement mortar 재질의 Plate 위에 액체질소를 연속적으로 누출시켜 Plate 표면에서 풀 확산이 일어나도록 하였다. 전자저울을 이용하여 Plate 위에서 증발되는 액체질소의 단위면적당증발률을 측정했고, 시간에 따라 반경 방향으로 퍼지는 액체풀의 확산 거리는 열전대의 온도 변화로부터 측정하였다. 실험 결과 액체질소의 단위면적당증발률은 풀 확산이 진행될수록 감소하는 경향을 보였다.

• Asian-Australasian Journal of Animal Sciences
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• 제4권4호
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• pp.369-375
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• 1991

A series of in vitro incubation studies with washed rumen bacteria were conducted to determine the influence of incubation time and concentrations of peptides, alanine, ammonia nitrogen and carbohydrate on the rate of peptide disappearance and on bacterial growth. Disappearance rate of tri-alanine (ala3) under various conditions was between 30.6 and $58.2mg\;hr^-$ per gram bacterial dry matter. Ala3 was removed from the incubation medium in an almost linear fashion as incubation time and ala3 concentration was increased. Washed rumen bacteria utilized ala3 faster than di-l-alanine (ala2) at all concentrations. Adding 9mM carbohydrate significantly increased ala3 disappearance, but level of ammonia nitrogen had no influence on ala3 disappearance. The presence of alanine in the medium significantly lowered ala3 utilization by rumen bacteria. Bacterial dry matter and nitrogen growth yield were not influenced by alanine and peptides when incubation medium already contained a sufficient level of ammonia nitrogen. Increased ammonia nitrogen in the presence of ala3 did not stimulate bacterial growth. Carbohydrate significantly increased bacterial dry matter and nitrogen growth as expected. Results indicate that the rate of peptide utilization by rumen bacteria may be altered by type and concentration of peptides, and energy supply, and this may be mediated through changes in numbers and type of bacteria.

• 한국수정란이식학회지
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• 제16권1호
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• pp.47-51
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• 2001

This study was done to examine the relationship between serum chemical values (urea nitrogen, glucose, total protein and cholesterol) of recipients and pregnancy rate following embryo transfer. Blood samples were taken from 184 Holstein heifers or cows on Day 6 or 7 (Day 0=day of estrus) to analysis for serum urea nitrogen, glucose, total protein and cholesterol concentrations. After selection of recipients, frozen Holstein embryos were thawed and directly transferred to recipients non-surgically. The average serum concentrations of urea nitrogen, glucose, total protein and cholesterol were 13.8 mg/dl, 56.5 mg/dl, 7.2 mg/dl, 124.8 mg/dl, respectively. The average concentrations of serum urea nitrogen and cholesterol were lower (P<0.05) in pregnant recipients (10.7 mg/dl, 99.2 mg/dl) than in non-pregnant recipients (13.0 mg/dl, 122.2 mg/dl), respectively, although the concentrations of glucose and total protein were not different. These results show serum urea nitrogen and cholesterol concentrations can be used important factors for selection of recipients in Holstein.

• 한국환경과학회지
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• 제13권7호
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• pp.661-665
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• 2004

As the concentration of ammonium nitrogen could be reached 2～3 mg/L in the winter in the river. It was clear that the excessive concentration of chlorinated organics could be produced with the increase of chlorine addition to remove ammonium nitrogen. In the innovative ammonium nitrogen removal process, zeolite adsorption is very efficient as substitute for rapid sand filtration without other adverse quality change in the water. This study is conducted to evaluate the feasibility of ammonium nitrogen removal and regeneration by zeolite adsorption in drinking water treatment. Also, the reuse possibility of zeolite is evaluated to change the removal efficiency of ammonium nitrogen through several times of regeneration. The ammonium nitrogen was not removed in sand filter, but it was almost removed in zeolite filter during 7 days. The sand and zeolite filters have a similar result of turbidity removal. Therefore, zeolite filtration was confirmed the removal of turbidity and ammonium nitrogen as a media. When compared KCl with NaCl as a chemical for zeolite regeneration, it is demonstrated that KCl was more efficient than NaCl in the ability of zeolite regeneration. The adsorption rate of ammonium nitrogen was almost not decreased in the results of several times of regeneration. It is indicated that both zeolite and regeneration solution were possible to reuse without variation of regeneration rate through this study.

• 한국식품저장유통학회지
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• 제5권2호
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• pp.123-126
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• 1998

This study was carried out investigate to optimum levels of nitrogen and phosphate fertilizer to get a higher yield and a quality of an onion(Allium Cepa L.) from 1993 to 1994. Three fertilizer levels were applied with 120, 240 and 360kg/ha of nitrogen and 100, 200 and 300kg/ha of P2O5 during the onion growing season. After harvesting the onion, it was storaged at given deposit. The growth and yield of the onion were better at the fertilizer levels of both 240 and 360kg/ha of nitrogen and of both 200 and 300kg/ha of P2O5 than at the level of 120kg/ha in nitrogen and 100kg/ha of P2O5. The content of total nitrogen and P2O5 in plant was decreased with reduced application levels of nitrogen and phosphate fertilizer. The rotting rate was higher at the levels of both 360kg/ha in nitrogen and 300kg/ha in P2O5 than the other treatment during the storage period. The sprouting rate tended to be high at 240kg/ha of nitrogen and 100kg/ha of P2O5.

• 한국작물학회지
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• 제48권6호
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• pp.527-533
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• 2003

질소시비량이 쌀의 품질 특성과 취반미의 향기성분에 미치는 영향을 알고자, 조생종인 대진벼, 중만생종인 일품벼와 추청벼를 공시하고, 질소 시비수준을 0, 5.5, 11, 16.5kg/10a로 처리하여 2001년에 포장실험을 수행한 결과는 다음과 같다. 1. 질소시비량이 증가할수록 세 품종 모두 쌀 수량은 고도로 유의하게 증가하였는데(r=$0.93^{**}\textrm{-}0.97^{**}$) 이는 단위면적당 수수가 유의하게 증가하였기 때문이었다. 2. 질소시비량이 증가함에 따라 현미 완전미율은 유의하게 감소하였고($-0.84^{**}$~$-0.91^{**}$), 불완전미율은 유의하게 증가하였다. 3. 질소시비량이 증가할수록 현미의 단백질 함량은 세 품종 모두 유의하게 높아졌고, 아밀로스 함량은 대진벼와 일품 벼에서는 유의하게 높아졌으나, 추청벼는 일정한 경향을 보이지 않았다. 4. 기계적 식미값은 대진벼와 일품벼에서는 질소시비량 0-11kg/10a 사이에 차이가 없었고, 16.5kg/10a에서는 매우 유의하게 감소하였다. 추청벼는 질소시비량에 비례하여 식미 값이 유의하게 감소하였다. 5. 쌀의 단백질 함량과 질소시비량 간에는 고도로 유의한 정의 상관(r=$0.88^{**}\textrm{-}0.96^{**}$)이, 질소시비량과 완전미율간에는 고도로 유의한 부의 상관(r=$-0.84^{**}$~$-0.91^{**}$)이, 그리고 질소시비량과 식미값 간에도 매우 유의한 부의 상관(r=$-0.72^{**}$~$-0.85^{**}$)이 나타났다. 6. 질소시비 처리한 추청벼 취반미의 취발성 방향 성분을 분석한 결과 총 11종이 검출되었다. 그러나 질소시비량이 증가함에 따라 방향 성분이 뚜렷하게 증가한다고 보기는 어려줬다. 7. 쌀의 수량과 품질을 동시에 고려할 때 질소시비량은 표준시비량(11kg/10a)이 가장 적정할 것으로 생각되며 식미를 높이기 위해 질소 시비량을 표준비 이하로 감소시킬 필요는 없을 것으로 판단되었다.

• 한국작물학회지
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• 제50권spc1호
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• pp.37-40
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• 2005

중산간지에서의 질소 시비량(0, 5, 7, 9, 11, 14, 17kg/10a)이 쌀의 품질에 미치는 영향을 검토하기 위하여, 3가지 품종(상미벼, 화영벼, 주남벼)을 대상으로 하여, 2개년간의 시험결과를 요약하면 다음과 같다. 1. 식미치는 질소시비량과 품종과의 상호작용 효과가 있었다. 즉 주남벼의 경우는 질소시비량에 따른 식미치의 차이는 없었으나, 화영벼의 경우는 질소 무비구가 5, 7, 17kg/10a 시비구보다 식미치가 높았으며, 상미벼의 경우는 7kg 시비구가 9, 11, 14, 17kg 시비구보다, 0, 5kg 시비구가 14, 17kg/10a 시비구보다 식미치가 높았다. 결과적으로 식미치는 품종에 따라 질소시비량에 대해 다르게 반응하는 것으로 나타났다. 2. Amylose 함량은 질소시비량간의 유의차는 인정되지 않았으나, 품종간의 Amylose 함량은 차이가 있어 상미벼<화영벼<주남벼 순으로 그 함량이 낮았다. 3. 단백질의 함량에서는 질소시비량과 품종간의 상호작용 효과가 인정된바, 주남벼와 화영벼의 경우는 질소시비량에 따른 차이가 없었고, 상미벼는 질소시비량이 적을수록 단백질의 함량이 낮았다. 4. 완전미와 백미의 수량은 질소시비량이 증가할수록 높았고, 품종간의 차이는 없었다. 5. 종전의 표준시비량인 질소 11kg/10a 시비구와 고품질 쌀 생산을 위해 새롭게 추천된 9kg시비구간의 쌀의 품질에 유의차는 인정되지 않았다. 6. 본 시험의 결과를 종합하면, 질소시비량에 따른 쌀의 품질은 품종에 따라 그 반응의 차이가 있어, 상미벼는 7kg/10a, 화영벼는 11kg, 주남벼는 14kg의 질소시비 수준에서 품질이 우수하고 수량이 높았다.

• 한국초지조사료학회지
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• 제21권4호
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• pp.203-210
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• 2001

To establish the recycling system of animal manure(AM) for environmental preservation and improve the utilization of AM, this study was to investigate the effects of the types and nitrogen application rate of AM on herbage productivity, efficiency of nitrogen utilization, nutritive value and an increase of soil fertility and in mixed grassland. This sudy was arranged in split plot design. Main plots were the types of AM(Cattle feedlot manure, CFM; Pig manure fermented with sawdust, PMFS; cattle sluny, CS) and subplots were the application rate of animal manure, such as 100, 200 and 300kgNiha. I. DM yields of herbage were the highest with CS and decreased by application over ZOOkgNiha AM. 2. Crude protein(CP) ontent was the highest with CFM and followed by CS, and the lowest with PMFS, and increased as application rate of AM increased. 3. Nitrogen(N) yields of CS treatment was higher than that of CFM and CS. and increased significantly as application rate of AM increased(P<0.05). 4. The contents of NDF, ADF and TDN was hardly influenced by the types and application rate of AM. 5. Organic matter(0M) content in the soil was the highest with PMFS and followed by CFM and the lowest with CS. OM content increased significantly as application rate of AM increased(P<0.05). 6. Total nitrogen content of the soil was not affected by the type of AM, but increased significantly as application rate of AM increased(P<0.05). (Key words : Animal manure, Grassland, Cattle feedlot manure, Pig manure fermented with sawdust, Cattle slurry, Soil fertility)