• 한국세라믹학회지
• /
• 제43권4호
• /
• pp.224-229
• /
• 2006

Ag-Pd alloy nanoparticles were prepared by a chemical reduction method using hydrazine $(N_2H_4)$ as a reductant in $AgNO_3\;and\;Pd(NO_3)_2$ aqueous solutions. Characterization of these particles by X-ray powder diffraction revealed a bimetallic and crystalline silver-palladium alloy. The average size of the particles was influenced not by the reductant $(N_2H_4)$ concentration, but the concentration of the starting materials $(AgNO_3\;and\;Pd(NO_3)_2)$.

• Bulletin of the Korean Chemical Society
• /
• 제23권2호
• /
• pp.179-183
• /
• 2002

Resonance-enhanced multiphoton ionization with time-of-flight product imaging of the $N(^2D)$ atoms has been used to study the $N_2O$ photodissociation at 118.2 nm and the two-photon dissociation at 268.9 nm. These imaging experiments allowed the determination of the total kinetic energy distribution of the $NO(X^2{\prod})$ and $N(^2D_{5/2})$ products. The $NO(X^2{\prod})$ fragments resulting from the photodissociation processes are produced in highly vibrationally excited states. The two-photon photodissociation process yields a broad $NO(X^2{\prod})$ vibrational energy distribution, while the 118.2 nm dissociation appears to produce a vibrational distribution sharply peaked at $NO(X^2{\prod},\;{\nu}=14)$.

• Korean Membrane Journal
• /
• 제8권1호
• /
• pp.36-42
• /
• 2006

We have prepared new water-swollen chitosan-$Ag^+$ complex membranes and studied their permeation and separation behavior for propylene and propane gases. The $Ag^+$ containing chitosan complex membranes were prepared from chitosan and $AgNO_3$ aqueous solution. The $AgNO_3$ and water content in the membrane were controlled by adjusting $AgNO_3$ concentration of casting solution. The permeation properties of propylene and propane were investigated as a function of $AgNO_3$ concentration, and various operation conditions. High permeability of above 17 barrer and high selectivity of above 170 could be obtained with the membranes prepared from 3 M $AgNO_3$ aqueous solution. Periodic regeneration test confirmed these membranes could be very useful for the separation of propylene/propane and other olefin/paraffin separation.

• 한국유기농업학회지
• /
• 제19권spc호
• /
• pp.74-77
• /
• 2011

The production practices, productivity and economic performance of organic and non-chemical rice farming were compared in Jeonnam Province, Korea. Korean organic rice farming showed a lack of use of resistant varieties and rotational cropping systems as well as less use of farm wastes and a high dependency upon external inputs. When compared with no-chemical rice production practices very little differences were found. However, organic rice farming showed 15% to 18% higher profits than no-chemical farming even though the productivity was arguably similar between the two farming types. This may encourage more farmers to convert to organic production rather than non-chemical farming as the farming practices are very similar, thereby resulting in increased supply of organic products and decreased prices for organic rice near future. There is a need to more greatly differentiate organic farming practices and products from those of no-chemical farming.

• 한국연소학회:학술대회논문집
• /
• 한국연소학회 제26회 KOSCO SYMPOSIUM 논문집
• /
• pp.129-136
• /
• 2003

Numerical study with momentum-balanced boundary conditions has been conducted to grasp chemical effects of added $CO_{2}$ and $H_{2}O$ to fuel- and oxidizer-sides on flame structure and NO emission behavior in $CH_{4}$/Air counterflow diffusion flames. The dilution with $H_{2}O$ results in significantly higher flame temperatures and NO emission, but dilution with $CO_{2}$ has much more chemical effects than that with $H_{2}O$. Maximum reaction rate of principal chain branching reaction due to chemical effects decreases with added $CO_{2}$. but increases with added $H_{2}O$. The NO emission behavior is closely related to the production rate of OH, CH and N. The OH radical production rate increases with added $H_{2}O$ but those of CH, N decrease. On the other hand the production rates of OR CH and N decrease with added $CO_{2}$. It is found that NO emission behavior is considerably affected by chemical effects of added $CO_{2}$ and $H_{2}O$.

• Korean Chemical Engineering Research
• /
• 제45권2호
• /
• pp.143-148
• /
• 2007

도시가스를 원료로 수소를 제조하여 연료전지에 활용할 경우에 도시가스에 포함된 황화합물이 개질기의 촉매와 연료전지의 전극에 독으로 작용하므로 금속이온이 담지 된 $\beta$-제올라이트(BEA)로 황화합물 흡착 제거를 수행하였다. 담지 된 금속염의 농도, 종류에 따라 파과흡착량이 달라졌으며, $AgNO_3$이 담지 된 흡착제가 실험에 사용된 흡착제 중 가장 높은 파과흡착량을 나타내었다(41.1 mg/g). 그러나 $Ni(NO_3)_2$, $Fe(NO_3)_3$, $Co(NO_3)_2$와 같은 금속염이 담지 된 BEA도 $AgNO_3/BEA$와 비교할 수준의 황화합물 흡착량을 나타냈다. $AgNO_3/BEA$ 흡착제 특성 분석과 온도 영향성 실험 및 X선 광전자 분광기(x-ray photoelectron spectroscopy, XPS) 분석을 통하여 흡착제와 황화합물 사이에 작용하는 힘은 금속이온과 황화합물간의 화학적 상호작용보다 물리적 상호작용이 우세한 것으로 나타났다.

• 대한화학회지
• /
• 제41권6호
• /
• pp.324-328
• /
• 1997

• Korean Chemical Engineering Research
• /
• 제50권5호
• /
• pp.825-829
• /
• 2012

본 연구에서는 전기분해 처리된 해수의 유효염소농도와 온도에 의한 배가스 중 NO의 산화 특성을 실험적으로 살펴보았다. 실험은 무격막식 전해수가 채워진 버블링 반응기에 반응가스를 공급하여 NO 농도의 변화를 분석하였다. 폐순환 전기분해 시스템의 경우 정전류 조건에서 전해 시간이 길어질수록 전해수 내에 유효염소농도가 상승하였고, 전해수의 유효염소농도가 높을수록 NO가 $NO_2$로 산화되는 반응이 촉진됨을 확인하였다. 또한 동일한 유효염소농도를 가지는 전해수의 경우에도 온도가 높을수록 NO 산화율이 증가하였다.

• Korean Chemical Engineering Research
• /
• 제43권2호
• /
• pp.324-329
• /
• 2005

본 연구에서 SNCR 공정에서 사용되는 NO의 농도는 500 ppm이며, 환원제로 Urea를 사용하였다. 또한 첨가제로 NaOH(sodium hydroxide), $Na_2CO_3$(sodium cabonate), $NaNO_3$(sodium nitrate), HCOONa(sodium formate), $CH_3COONa$(sodium acetrate)를 이용하여 온도와 첨가제에 따른 NO 저감 효율을 측정하고자 하였다. 이때의 NO 저감 온도의 범위는 $650-1,050^{\circ}C$이다. 환원제만 사용하였을 경우, NO의 저감 효율은 44%까지 증가하였으며, 환원제와 첨가제(NaOH)를 0.5 mol/L와 1 mol/L 사용하였을 경우, NO 저감 효율은 25%와 74%이상 증가하였다. 첨가제를 사용하지 않았을 경우보다 첨가제를 사용하였을 경우 NO의저감 효율은 증가하였다. 또한 NaOH>$Na_2CO_3$>$NaNO_3$>HCOONa, >CHCOONa 첨가제의 순으로 효율이 우수하였다. 첨가제를 사용할 경우 약 $900^{\circ}C$에서 $1,050^{\circ}C$의 온도범위에서 NO저감 효율이 65% 이상으로 나타났다. 온도 창의 범위는 약 $250^{\circ}C$의 범위로 나타났으며, 최저 효율은 약 20%이며 최대효율은 약 74%정도로 나타났다.

• 한국응용과학기술학회지
• /
• 제12권1호
• /
• pp.125-131
• /
• 1995

Ultra thin films of Tetra-3-hexadecylsulphamoylcopperphthalocyanine(HDSM-CuPc) were formed on various substrates by Langmuir-Blodgett method, where HDSM-CuPc was synthesized by attaching long-chain alkylamine(hexa-decylamine) to CuPc. The reaction product was identified with FT-IR, UV-visible absorption spectroscopies, elemental analysis and thin layer chromatography. The formation of Ultrathin Langmuir-Blodgett(LB) films of HDSM-CuPc was confirmed by FT-IR and UV-visible spectroscopies. A quartz piezoelectric crystal coated with LB films of HDSM-CuPc was examined as a gas sensor for $N0_2$ gas. HDSM-CuPc LB films were transferred to a quartz crystal microbalance(QCM) in the form of Z-type multilayers. Response characteristics of film-coated QCM to $NO_2$ gas concentrations over a range of $100{\sim}600ppm$ have been tested with a thickness of $5{\sim}20$ layers of HDSM-CuPc. Changes in frequency by adsorption of $NO_2$ were increased With the number of LB layers and $NO_2$ concentration, but the response time was slow.