• 제목/요약/키워드: $N_2$ flow rate

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소화성능이 있는 질소발생기의 방사량 결정에 관한 실험적 연구 (An Experimental Study on the Determination of the Flow Rate for a Feasible $N_2$ Generator to Extinguish the Fire)

  • 장영근;김덕주;서병택
    • 한국화재소방학회논문지
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    • 제24권6호
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    • pp.54-60
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    • 2010
  • 본 연구는 할론 계열의 소화약제를 대체할 수 있는 청정소화약제인 질소가스를 생산하는 산업용 질소발생기를 사용하여 임의 방호구역에 대한 질소발생기의 방사압력에 따른 방사량을 결정할 수 있는 상관관계식을 실험적으로 결정하였다. 질소발생기의 방사량을 결정할 수 있는 상관관계식을 결정하기 위하여 간단한 방호구역을 제작하여 소형 질소발생기에서 발생하는 질소가스의 방사압과 방사량을 변화시키며 방호구역 내의 산소농도 변화를 실험적으로 파악하였다. 실험결과를 가지고 무유출인 경우 임의 방호구역에 대한 소화약제 방사량과 산소농도와의 관계를 정의한 이론식에 대하여 실험한 산소농도와의 차이를 분석하여 실험결과에 가장 근접하는 상관관계식을 결정하였다. 결정한 상관관계식은 임의 방호구역, 방사압력 및 방사량에 대하여 실험하여 검증한 결과 비교적 잘 일치하였다. 따라서 본 연구를 통하여 결정된 상관관계식을 이용하여 임의 방호구역에 대한 질소발생기의 방사량을 결정할 수 있는 방사량 결정 선도를 완성하였다.

산화인듐아연 박막 트랜지스터에서 질소 첨가가스가 활성층의 물성 및 소자의 특성에 미치는 영향 (Effects of Nitrogen Additive Gas on the Property of Active Layer and the Device Characteristic in Indium-zinc-oxide thin Film Transistors)

  • 이상혁;방정환;김원;엄현석;박진석
    • 전기학회논문지
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    • 제59권11호
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    • pp.2016-2020
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    • 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.

질소 첨가된 ta-C 후막코팅의 기계 및 트라이볼로지적 특성연구 (Effects of nitrogen doping on mechanical and tribological properties of thick tetrahedral amorphous carbon (ta-C) coatings)

  • 강용진;장영준;김종국
    • 한국표면공학회:학술대회논문집
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    • 한국표면공학회 2016년도 추계학술대회 논문집
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    • pp.156-156
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    • 2016
  • The effect of nitrogen doping on the mechanical and tribological performance of single-layer tetrahedral amorphous carbon (ta-C:N) coatings of up to $1{\mu}m$ in thickness was investigated using a custom-made filtered cathode vacuum arc (FCVA). The results obtained revealed that the hardness of the coatings decreased from $65{\pm}4.8GPa$ to $25{\pm}2.4GPa$ with increasing nitrogen gas ratio, which indicates that nitrogen doping occurs through substitution in the $sp^2$ phase. Subsequent AES analysis showed that the N/C ratio in the ta-C:N thick-film coatings ranged from 0.03 to 0.29 and increased with the nitrogen flow rate. Variation in the G-peak positions and I(D)/I(G) ratio exhibit a similar trend. It is concluded from these results that micron-thick ta-C:N films have the potential to be used in a wide range of functional coating applications in electronics. To achieve highly conductive and wear-resistant coatings in system components, the friction and wear performances of the coating were investigated. The tribological behavior of the coating was investigated by sliding an SUJ2 ball over the coating in a ball-on-disk tribo-meter. The experimental results revealed that doping using a high nitrogen gas flow rate improved the wear resistance of the coating, while a low flow rate of 0-10 sccm increased the coefficient of friction (CoF) and wear rate through the generation of hematite (${\alpha}-Fe_2O_3$) phases by tribo-chemical reaction. However, the CoF and wear rate dramatically decreased when the nitrogen flow rate was increased to 30-40 sccm, due to the nitrogen inducing phase transformation that produced a graphite-like structure in the coating. The widths of the wear track and wear scar were also observed to decrease with increasing nitrogen flow rate. Moreover, the G-peaks of the wear scar around the SUJ2 ball on the worn surface increased with increasing nitrogen doping.

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PECVD법에 의해 증착된 $SiO_2$후막 특성에서 $N_2O$/$SiH_4$Flow Ratio와 RF Power가 미치는 영향 (Effects of $N_2O$/$SiH_4$Flow Ratio and RF Power on Properties of $SiO_2$Thick Films Deposited by Plasma Enhanced Chemical Vapor Deposition)

  • 조성민;김용탁;서용곤;임영민;윤대호
    • 한국세라믹학회지
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    • 제38권11호
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    • pp.1037-1041
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    • 2001
  • 저온(32$0^{\circ}C$)에서 SiH$_4$$N_2$O 가스의 혼합을 통해 플라즈마화학기상증착(PECVD)법을 이용하여 실리카 광도파로의 클래딩막으로 사용되는 SiO$_2$후막을 제조하였다. 증착변수가 SiO$_2$후막의 특성에 미치는 영향을 살펴보기 위해 $N_2$O/SiH$_4$flow ratio와 RF power에 변화를 주었다. $N_2$O/SiH$_4$ flow ratio가 감소함에 따라 증착속도는 2.9 $mu extrm{m}$/h), 굴절률은 thermal oxide의 굴절률(n=1.46)에 근접하였다.

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Effect of Aeration and Agitation Conditions on the Production of Glucoamylase with Aspergillus niger No. PFST-38

  • Oh, Sung-Hoon;O, Pyong-Su;Lee, Cherl-Ho
    • Journal of Microbiology and Biotechnology
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    • 제3권4호
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    • pp.292-297
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    • 1993
  • Aspergillus niger No. PFST-38 was grown on complex media in 30L agitated fermentors at various aeration rates and stirrer speeds. We could correlate the mixing time as a function of the Reynolds number and the apparent viscosity, as follows. ${\theta}_M=2.95\;\NRe^{-0.52},\;{\theta}_M=1.88\;{\eta_a}^{0.57}$ Also, the effects of the apparent viscosity (${\theta}_a$), the impeller rotational speed (N), the air flow rate ($V_s$), and the mixing time (${\theta}_M$) on the oxygen transfer coefficient, $K_L a$ were determined experimentally, and equated as follows. $K_La=12.04N^{0.88}Vs^{0.71}{n_a}^{-0.83},\;K_La=30.2N^{0.88}Vs^{0.71}{\theta_M}^{-1.45}$ $K_La$ increased as the agitation speed and the air flow rate increased. The rate of $K_La$ increase was dependent more on the rotational speed of impeller than on the air flow rate. The glucoamylase production increased with the increase of the agitation speed upto at 500 rpm and increased with the increase of air flow rate upto at 1.0 vvm. The values calculated from the above equation confirmed that the experimental maximum production of glucoamylase was achieved when the $K_La$ and the apparent viscosity of the broth were $260\;hr^{-1}$ and 1800 cps, respectively.

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MOCVD 반응로내 GaN 성장에 미치는 입구형상의 영향 (Effect of inlet configuration on the growth rate of GaN layer in a MOCVD reactor)

  • 윤성규;백병준;박복춘
    • 대한기계학회:학술대회논문집
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    • 대한기계학회 2003년도 추계학술대회
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    • pp.67-72
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    • 2003
  • Numerical calculation has been performed to investigate the effect of inlet configuration on the growth rate of GaN layer on the heated susceptor. The conventional single inlet, where the gas is mixed by force in the inlet, is compared with separated flow inlet. Two-parallel gas flow $H_{2}$ and $NH_{3}$ are separated by a plate with finite length which are also parallel to the susceptor. The effect of separated plate length, carrier gas and flow rate of each precursor on the mixing of reactant gases and growth rate were investigated. Furthermore the three dimensional model is employed to predict the transverse variation of growth rate.

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EFFECT OF SOYBEAN EXTRUSION ON NITROGEN METABOLISM, NUTRIENT FLOW AND MICROBIAL PROTEIN SYNTHESIS IN THE RUMEN OF LAMBS

  • Ko, J.Y.;Ha, J.K.;Lee, N.H.;Yoon, C.S.
    • Asian-Australasian Journal of Animal Sciences
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    • 제5권3호
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    • pp.571-582
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    • 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.

RF PECVD법에 의해 증착된 TiN 박막의 조성, 구조 및 전기적 특성 (Composition, Structure and Resistivity of TiN Thin, Films Deposited by RF PECVD)

  • 전병혁;김종석;이원종
    • 한국재료학회지
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    • 제5권5호
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    • pp.552-559
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    • 1995
  • Titanium nitride films were deposited on the (100) oriented-p-type silicon substrates of RF plasma enhanced chemical vapor depositiom\n using a gaseous mixutre of TiCl$_{4}$, N$_{2}$, H$_{2}$ and Ar. The chemincal composition, structure and the rsistivituy of the films were investigated with the deposition variables such as the flow rate ratio of N$_{2}$/TiCl$_{4}$, the deposition temperature and the RF power. The deposition rate increases with increasing the flow rate ratio of N$_{2}$TiCl$_{4}$ and RF power, while the rate decreases with increasing the deposition temperature. As the flow rate ratio of N$_{2}$/TiCl$_{4}$ and depostion temperature increases within proper RF pwoer, the Cl concentartion in the films decreases and the stoichiometry and crystallingiy are improved, so decreases the resistivity of the films. The films depostied under the condition of the N$_{2}$/TiCl$_{4}$ ratio of 30, the RF power of 50W and the depostion temperature of 62$0^{\circ}C$ had the Cl content of 1.5at% and the resistivity of 56㏁cm. Also, the bottom coverage of the films was above 60% on the step with the width and depth of 0.6${\mu}{\textrm}{m}$$\times$0.6${\mu}{\textrm}{m}$.

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Growth and Properties of CrNx/TiNy/Al Based on N2 Gas Flow Rate for Solar Thermal Applications

  • Ju, Sang-Jun;Jang, Gun-Eik;Jang, Yeo-Won;Kim, Hyun-Hoo;Lee, Cheon
    • Transactions on Electrical and Electronic Materials
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    • 제17권3호
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    • pp.146-149
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    • 2016
  • The CrN/TiN/Al thin films for solar selective absorber were prepared by dc reactive magnetron sputtering with multi targets. The binary nitride CrN layer deposited with change in N2 gas flow rates. The gas mixture of Ar and N2 was an important parameter during sputtering deposition because the metal volume fraction (MVF) was controlled by the N2 gas flow rate. In this study, the crystallinity and surface properties of the CrN/TiN/Al thin films were estimated by X-ray diffraction (XRD), atomic force microscopy (AFM) and field emission scanning electron microscopy (FESEM). The composition and depth profile of thin films were investigated using Auger electron spectroscopy (AES). The absorptance and reflectance with wavelength spectrum were recorded by UV-Vis-NIR spectrophotometry at a range of 300~1,100 nm.

UNTEADY HEAT FLOW AND TEMPERATURE VARIATION IN HUMAN SST REGIONS

  • Sanyal, D.C.;Maji, N.K.
    • Journal of applied mathematics & informatics
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    • 제9권2호
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    • pp.731-744
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    • 2002
  • The temperature distribution in human skin and subdermal tissue layer is presented using bioheat transfer equation. The body temperature is determined by the balance between heat produced and heat lost by our body. The time-dependent solutions have been found to be affected by the metabolic heat generation rate, blood mass flow, the rate of evaporation of perspiration and also by the atmospheric temperature. The analytic solutions for different layers have been calculated numerically and are also shown graphically.