• 한국환경보건학회지
• /
• 제35권1호
• /
• pp.64-70
• /
• 2009

The aims of this study is to examine the effects of the changes in HRT(Hydraulic Retention Time) and media charge in a water-mill, among other operation factors, on the nitrogen and phosphorus removal in order to use up-flow anaerobic reactors, anoxic reactors and water-mill aerobic reactors for sewage treatment. The extension of HRT improved the nitrogen removal efficiency, however the removal pattern was constant regardless of HRT. The removal of phosphorus was constant (80%-90%) regardless of the change in HRT. The removal rate with change in influx load varied such that at the OLR (Organic Load Rate) of 1-3 kg/d, the T-N removal efficiency was 80.7%-88.9% and the T-P removal efficiency was 82.9%-89.3% while at the NLR (Nitrogen Loading Rate) of 0.108-0.156 kg/d the removal efficiencies were 80.7-88.9% (T-N) and 82.9-89.3% (T-P). The analyses of the nitrogen and phosphorous removal characteristics with the C/N and C/P ratio showed that the mean T-N removal rate was 88% at the C/N ratio of 1.2-2.6, and that the mean T-P removal rate was 86% at the C/P ratio of 7.2-14.1. Also, the analysis of nitrogen and phosphorous removal characteristics were analyzed in relation to media charge. The comparison between with and without media charge in the water-mill showed that while the nitrogen removal efficiencies were 86-94% and 85-89% respectively, the difference of phosphorous removal efficiencies were between the two conditions was not significant, thus it suggested that the media charge has less effect on the removal efficiency of phosphorous compared to that of nitrogen.

• 청정기술
• /
• 제15권4호
• /
• pp.280-286
• /
• 2009

고농도의 질산성 질소를 함유하는 폐수의 처리에 전기투석법의 적용 가능성을 평가하기 위하여 전기투석 공정의 운전인자 중 유입농도, 운전전압, 그리고 유속이 질산성 질소의 제거효율에 미치는 영향을 실험적으로 평가하였다. 한계전류밀도는 유입농도와 유입유속이 증가함에 따라 선형적으로 증가하였다. 유입농도와 목표농도에 도달하는 시간은 직선적으로 비례관계를 보였고, 농축액의 초기농도가 제거속도에 미치는 영향은 거의 없었다. 저속에서 유입유속의 증가는 제거속도를 증가시켰지만, 일정속도 이상에서는 제거속도에 미치는 영향이 미미하였다. 운전전압의 증가에 따라 제거속도는 증가하였지만 그 증가속도는 점차 저하되었다. 본 연구에 사용된 전기투석모듈에서 고농도의 질산성 질소를 제거하는 최적 운전조건으로 유입유속 1.6 L/min, 한계전류밀도의 80~90%의 해당하는 운전전압이 권장된다.

• 한국수소및신에너지학회논문집
• /
• 제34권6호
• /
• pp.741-747
• /
• 2023

In this study, the heat transfer characteristics were numerically analyzed to investigate the possibility of utilizing cooling water using liquid nitrogen. From the study, as the mass flow rate of the hot fluid increased, the heat transfer rate increased by 8.9-81.7%. And lowering the inlet temperature of the hot fluid resulted in increase in the heat transfer rate by 33.8-71.5%. As for the filling level of liquid nitrogen, as higher filling level led to a decrease in the outlet temperature and an increase in the overall heat transfer coefficient.

• E2M - 전기 전자와 첨단 소재
• /
• 제8권2호
• /
• pp.196-203
• /
• 1995

We presented Tungsten and Tungsten Nitride thin films deposited by RF and DC sputtering. It deposited at various conditions that determining the resistivity and sheet resistivity by stabilizing the basic theory. We investigated properties of the resistivity and sheet resistivity of these films under various conditions, temperature of substrate, flow rate of the argon gas and content of nitrogen from nitrogen-argon mixtures. As the temperature of substrate increased and the flow rate of the argon gas decreased, the resistivities of these films reduced by structural transformation. We found that these resistivities were depend on the temperature of substrate, flow rate and electric power. Very highly resistive tungsten films obtained at 10W RF power. On the contrary, we found that films deposited by DC sputtering, from which very lowly resistive tungsten films were obtained. Tungsten nitride thin films deposited by reactive DC sputtering and the resistivities of these films increased as the content of nitrogen gas increased from nitrogen-argon mixture. And also we found the results show very good agreement, compared with experimental data.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2009년도 제38회 동계학술대회 초록집
• /
• pp.384-384
• /
• 2010

Zirconium oxynitride films were obtained by r.f. reactive magnetron sputtering of a zirconium target with nitrogen flow rate ranging from 0 to 60 sccm. The phases present in the films were determined by X-ray diffraction (XRD). Measurements of the oxidation state $ZrON_x$ films were investigated by X-ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy (AES). Thickness of these samples was estimated by spectroscopic ellipsometry (SE) and scanning electron microscopy (SEM). We found that the surface morphology of $ZrON_x$ films measured by atomic force microscopy (AFM) was also depended on the nitrogen gas flow.

• 항공우주시스템공학회지
• /
• 제14권5호
• /
• pp.26-32
• /
• 2020

본 연구에서는 액체로켓 연소기의 연소 불안정 모사를 위해 극저온 유체인 액체질소를 공급하는 설비를 구축하였다. 가압 및 공급 성능을 예측하였으며 실험을 통하여 검증하였다. 액체질소 공급 시스템은 가압식 공급 시스템으로 구성하였으며, 가압제 압력 조정은 돔 레귤레이터를 사용하였다. 액체질소 공급 유량 제어는 캐비테이션 벤추리를 사용하였으며, 액체 질소 공급 조건은 초당 유량 2.55 kg/s, 벤추리 입구 압력은 100 bar 이상이다. 초기 실험 결과 예측된 가압제의 양이 충분히 공급되지 못하여, 탱크압력 강하가 발생해 목표 유량을 공급하지 못하였다. 구축된 설비의 변경 및 보완을 통하여, 최종적으로 목표 유량 공급에 성공하여 극저온 액체질소 공급 설비를 검증하였다.

• 한국전기전자재료학회:학술대회논문집
• /
• 한국전기전자재료학회 1997년도 추계학술대회 논문집
• /
• pp.94-97
• /
• 1997

We investigated the sheet resistance properties of tungsten nitride thin films deposited by RF and DC sputtering system. It deposited at various conditions that determine the sheet resistance. The properties of the sheet resistance of these films were measured under various conditions. Sheet resistance analysed under the flow rate of the argon gas and contents of nitrogen from nitrogen-argon gas mixtures. We found that these sheet resistance were largely depend on the temperature of substrate, gas flow rate and RF power. Very high and low sheet resistance of tungsten films obtained by DC sputtering. As the increase of contents of nitrogen gas obtained from nitrogen-argon gas mixture, tungsten nitride thin films deposited by the reactive DC sputtering and the sheet resistance of these films were increased.

• Asian-Australasian Journal of Animal Sciences
• /
• 제5권3호
• /
• pp.571-582
• /
• 1992

Soybeans were dry extruded at three different temperatures (125, 135 and $145^{\circ}C$) for 30 s. Four lambs fitted with cannulae in the rumen and abomasums were used in a balanced $4{\times}4$ Latin square design. Lambs were fed at 2 h intervals for 12 times a day with automatic feeder to maintain steady state conditions in digestive tract. A dual-phase marker system was used to estivate ruminal flow rate of both liquid and solid digesta. Objectives of this study were to determine the effect of extrusion temperature of raw soybean on the ruminal liquid and solid dilution rate, nitrogen digestion and flow at the abomasum and availability of amino acid in lambs. There were no significant effects of extrusion on liquid and solid dilution rate, and liquid volume. Ruminal liquid flow rate was not influenced by extrusion and ranged from 389 to 435 ml/hr. Extrusion had no influence on ruminal OM digestion and flow rate to the abomasums. Dietary N flow to the abomasums increased (p < 0.05) as extruding temperature increased. Extruding temperature had a significant effect (p < 0.05) on flow of N escaping ruminal degradation and ranged from 34.91 to 57.38%. Microbial N synthesized/kg OMTDR ranged from 27 to 37 g and highest with $145^{\circ}C$ ESB diet. Extrusion decreased the amount of degradable amino acid in the rumen and increased the supply of amino acid to the lower gut, especially with 135 and $145^{\circ}C$ ESB diets.

• 전기학회논문지
• /
• 제59권11호
• /
• pp.2016-2020
• /
• 2010

Indium-zinc-oxide (IZO) films were deposited at room temperature via RF sputtering with varying the flow rate of additive nitrogen gas ($N_2$). Thin film transistors (TFTs) with an inverted staggered configuration were fabricated by employing the various IZO films, such as $N_2$-added and pure (i.e., w/o $N_2$-added), as active channel layers. For all the deposited IZO films, effects of additive $N_2$ gas on their deposition rates, electrical resistivities, optical transmittances and bandgaps, and chemical structures were extensively investigated. Transfer characteristics of the IZO-based TFTs were measured and characterized in terms of the flow rate of additive $N_2$ gas. The experimental results indicated that the transistor action occurred when the $N_2$-added (with $N_2$ flow rate of 0.4-1.0 sccm) IZO films were used as the active layer, in contrast to the case of using the pure IZO film.

• 융복합기술연구소 논문집
• /
• 제1권2호
• /
• pp.37-42
• /
• 2011

The purpose of this research is to improve nitrogen removal efficiency in winter season through rise of water temperature of extraneous water by using solar energy which is estimated to have great potential among new regeneration energy and while operating Plug-Flow Reactor to improve nitrogen removal efficiency by selecting A/O process among sewage waste water treatment processes as the necessity of solving the problem of nitrogen removal efficiency according to reduced water temperature in winter season and strengthening of water quality criteria regarding discharged sewage waste water suggested in the research background. Summarizing the research result, supply of solar energy source improves the function outstandingly when removing nitrogen, (nitrogen removal rate before operating solar energy 55.4% ${\rightarrow}$ nitrogen removal rate after operating solar energy 84.1%).