• 한국응용과학기술학회지
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• 제22권2호
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• pp.168-174
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• 2005

Aluminum tri-butoxide was mixed with the water/ethanol solution and then chloroplatinic acid was added to the solution. The solution was dried at $100^{\circ}C$ for 15hrs to remove the solvent and water then it was calcined at $500^{\circ}C$. The catalyst was activated with a gas mixture. During the activation, the temperature was increased from $150^{\circ}C$ to $500^{\circ}C$. The necessary amount of urea was dissolved in 50mL water and injected. Aqueous urea solution was then mixed with the feed gas stream. At low temperatures, nitrogen containing compounds of urea decomposition are used as reductants in the reducton of $NO_X$. However at high temperatures the nitrogen containing compounds are oxidized to NO and $NO_2$ by oxygen instead of being used in the reduction. The activity of the catalyst was dependent on urea concentration in the feed stream when there was not adequate water vapor in the feed. The maximum conversion was shifted from $250^{\circ}C$ to $150^{\circ}C$ when water concentration was increased from 2 to 17%. It seems that the maximum temperature shifts to lower temperatures because the hydrolysis rate of HNCO increases with water, resulting in higher amounts of $NH_3$.

• 유기물자원화
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• 제13권4호
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• pp.136-147
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• 2005

난분해성 유기물과 암모니아성 질소의 동시제거를 위해 간헐폭기 생물활성탄 유동상법을 이용하여 고농도 유기물함유 침출수에 대하여 실험을 수행하였다. 간헐폭기시 고려되어야 하는 폭기 시간과 비폭기 시간에 대하여 실험적 검토를 수행하였고 자동컴퓨터제어 가능성에 대하여 고찰하여 보았다. 그 결과 생물활성탄 유동상 반응조에 충전한 활성탄의 물리적 흡착능은 초기의 처리효율에 크게 기여하였으며 간헐폭기 생물활성탄 유동상에 의한 침출수 처리시 정상상태에 도달하는 시간은 40일 정도이었고 TOC와 암모니아성 질소 처리시 양호한 프로세스임을 알 수 있었다. 폭기 및 비폭기시간은 60분 폭기/60분 비폭기의 조건이 30분 폭기/90분 비폭기에 비해 처리효율이 양호하게 나타났고 고농도 유기물함유 침출수 처리실험에서 간헐폭기 생물활성탄 유동상에 의한 처리방법은 높은 TOC제거율, 질산화율 및 탈질율, 난분해성 유기탄소 제거율을 확인할 수 있었다. 또한 간헐폭기시 ORP 곡선의 변화에서 나타나는 굴곡점은 무산소상태의 종결점을 나타내는 파라메터로 이용가능하며 이를 간헐폭기 반응조의 최적 운전모드를 설정하는데 응용할 경우 소규모 자동화가 가능할 것으로 판단되었다.

• 한국수산과학회지
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• 제25권5호
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• pp.371-382
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• 1992

자주새우, Crangon affinis 서식지의 동계$(7^{\circ}C$, 춘. 추계$(15^{\circ}C$ 및 하계$(25^{\circ}C$의 평균 수온대에서 일정기간 (0, 5, 11, 17, 25days) 절식시킨 후 체물질의 화학적조성, 산소소비 및 질소배설률을 측정하여 환경변화에 대한 생리적 적응의 일면을 조사하였다. 1. 자주새우의 체물질조성은 단백질 $68.6\%$, 지질 $7.0\%$, 탄수화물$4.1\%$, 키틴$6.3\%$, 그리고 회분은 $14.6\%$였다. 2. 기아상태 에 서도 고온일수록 탈피 빈도는 높았으며 동일 절식기간 동안 고온일수록 체중 및 체물질의 감소는 더욱 컸다. 3. 산소소비율은 기아가 계속됨에 따라 고온일수록 현저히 감소하는 경향을 보였으나 기아 25일 경과 후의 각 수온구별 산소소비율은 유사하였다. 4. 수온별 각 실험구간의 $Q_{10}$치는 실험온도구간에 큰 차이를 보이지 않았으나 기아가 계속됨에 따라 상당히 감소하였다. 5. 총배설질소량은 고온일수록 증가하였으며 배설질소의 주성분은 암모니아였다 그리고 총배설질소량은 어느 실험수온구에서나 기아가 계속됨에 따라 현저하게 증가하였다. 6. 기아 25일 경과후 수온 7, 15 및 $25^{\circ}C$에서 이화된 단백질은 각각 체단백질의 1.8, 2.5 및 $3.3\%$였다. 7. 기아초기의 O:N 원자비는 22-25이고, 기아상태가 지속됨 에 따라 8이하로 낮아져 기아동안의 에너지원으로 단백질을 이용함을 보였다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2016년도 제50회 동계 정기학술대회 초록집
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• pp.208.2-208.2
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• 2016

Many researchers have paid attention to the studies on the interaction between non-thermal plasma and aqueous solutions for biomedical applications. The gas composition in the plasma is very important. Oxygen and nitrogen are the main gases of interest in biological applications. Especially, we focus on the oxygen concentration. In this experiment, we studied the role of oxygen concentration in plasma induced chemical reactions in solution. At first, the amount of ions are measured according to changing the oxygen concentration. And we checked the relationship between these ions and pH value. Secondly, when the oxygen concentration is changed, it identified the type and amount of radical generated by the plasma. In order to confirm the effect of these chemical property change to biological material, hemoglobin and RBCs are chosen. RBCs are one of the common basic biological cells. Thirdly, when plasma treated according to oxygen concentration in nitrogen feeding gas, oxidation of hemoglobin and RBC is checked. Finally, membrane oxidation of RBC is measured to examine the relation between hemoglobin oxidation and membrane damage through relative hemolysis and Young's modulus. Our results suggest that reactive species generated by the plasma differsdepending on the oxygen concentration changes. The pH values are decreased when oxygen concentration increased. OH decrease and NO increase are also observed. These reactive species makes change of chemical properties of solution. We also able to confirm that the difference in these reactive species to affect the oxidation of the Hb and RBCs. The Hb and RBCs are more oxidized with the high oxygen concentration conditions. But membrane is damaged more by plasma treatment with only nitrogen gas. It is shown that red blood cells membrane damage and oxidation of hemoglobin are not directly related.

• Environmental Engineering Research
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• 제21권3호
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• pp.311-317
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• 2016

A new type of biofilter packed with composite carriers was designed for tertiary denitrification of the secondary effluent with removal of both oxidized nitrogen and suspended solids (SS). At the empty bed residence time of 15 min and organic carbon to nitrate nitrogen ($C/NO_3-N$) ratios of 2, 1.5 and 1 g/g, the removal percentage of $NO_3-N$ was 67%, 58% and 36% in the ethanol biofilter, and was 61%, 43% and 26% in the acetate biofilter, respectively. The biofilters packed with composite carriers removed SS effectively, with the effluent turbidity in both biofilters of less than 3 NTU. During the operating cycle between the biofilter backwashings, the $NO_3-N$ removal percentage decreased initially after backwashing, and then gradually increased. Under $C/NO_3-N$ ratios of 2, 1.5 and 1 g/g, the $NO_3-N$ reduction rate was 1.75, 1.04 and $0.68g/m^2/d$ in the ethanol biofilter, and was 1.56, 1.07 and $0.76g/m^2/d$ in the acetate biofilter, respectively. In addition, during denitrification, the ratio of the consumed chemical oxygen demand to the removed $NO_3-N$ was 5.06-8.23 g/g in the ethanol biofilter, and was 4.26-8.6 g/g in the acetate biofilter.

• 한국재료학회지
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• 제14권10호
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• pp.683-687
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• 2004

The BON thin films were grown on the Si substrate by the RF-PECVD method. When stored at the room temperature, the phase separation or transition of BON thin films occurred on the surface, due to the hydrophilic property of BON. The oxidation of BON thin films occurred mainly by the evaporation of B, O and N. The oxidized BON thin films consisted of an amorphous phase and a bit of the polycrystalline phase.

• 한국세라믹학회지
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• 제32권1호
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• pp.31-36
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• 1995

(100) Si was oxidized in N2O ambient, and the film properties of oxynitride dielectrics were compared with pure SiO2. The growth rate, after pre-oxidation in O2/N2 ambient with raising temperature, is faster than that of O2/N2O treatment during the same condition. Nitrogen piles up at the interface of SiO2 and Si substrate and the content is about 2atom%. Comparing with pure SiO2, oxynitride dielectrics shows less dielectric breakdown failures and flat-band voltage shift, and good diffusion barrier property to dopant(BF2) is also observed.

• 한국초전도저온공학회:학술대회논문집
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• 한국초전도저온공학회 2000년도 KIASC Conference 2000 / 2000년도 학술대회 논문집
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• pp.85-88
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• 2000

Cu-free Bi-Sr-Ca-O powder mixtures were screen-printed on Cu tapes and heat-treated at 850-$870^{\circ}C$ for several minutes in air, oxygen, nitrogen and low oxygen pressure. Cu-free precursors were composed of Bi_{x}$SrCaO_{y}$ (x=1.2-2). In order to obtain the optimum heat-treatment condition, we studied on an effect of the precursor composition, the printing thickness and the heat-treatment atmosphere on the superconducting properties of Bi2212 films and the reaction mechanism of their rapid formation. Microstructures and phases of thick films were analyzed by optical microscope and XRD. The electric properties of superconducting films were examined by the four probe method. At heat-treatment temperature, the thick films were in a partially molten state by liquid reaction between CuO in the oxidized copper tape and the precursors which were printed on Cu tapes.

• 한국표면공학회지
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• 제40권1호
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• pp.39-43
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• 2007

The pure CrN powders oxidized to $Cr_2O_3$ noticeably above $850^{\circ}C$ in air. When these powders were sintered into bulk samples at $1500^{\circ}C$ under 40 atm of $N_2$ pressure, the CrN phase partly changed into the $Cr_2N$ phase, owing to the partial loss of nitrogen from CrN. When the bulk sample was heated at $1000-1200^{\circ}C$ for 100 hr under vacuum, the CrN phase also progressively changed into $Cr_2N$. At the same time, a relatively thin $Cr_2O_3$ layer formed on the bulk sample due to the reaction of chromium with residual oxygen in vacuum.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2005년도 총회 및 춘계학술발표회
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• pp.393-396
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• 2005

The reactive transport model on the biologically mediated sequential nitrate transformation and its subsequent transport was developed and tested. This model was coded as a reaction module within the RT3D framework (Clement, 1997). Transports of the reasonable six mobile solutes (dissolved organic carbon, $O_2,\;{NO_3}^-,\;{NO_2}^-,\;N_2O,\;N_2$) and two immobile microbes were simulated. The simulation results gave a reasonable match with supposed transport pattern. For the next step, the developed model will be validated against experimental data.