• Title/Summary/Keyword: Nitrates

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Effects of Catalyst Metal and Substrate Temperature on a Flame Synthesis of Carbon Nanomaterials (화염을 이용한 탄소나노튜브와 나노섬유의 합성에 미치는 촉매금속 및 기판온도의 영향)

  • Lee, Gyo-Woo;Jurng, Jong-Soo;Hwang, Jung-Ho
    • Journal of the Korean Society of Combustion
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    • v.8 no.2
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    • pp.27-33
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    • 2003
  • Synthesis of carbon nanomaterials on a metal substrate by an ethylene fueled inverse diffusion flame was illustrated. Stainless steel plates were used for the catalytic metal substrate. The effects of catalyst metal particles were investigated through $Fe(NO_3){_3}$ (ferric nitrate, nonahydrate) and $Ni(NO_3){_2}$ (nickel nitrate, hexahydrate). Carbon nanotubes and nanofibers with diameters of $30{\sim}70nm$ were found on the substrate for the case of using SUS304 substrates only and using them with metal nitrates. In case of using metal nitrates, due to the easy activation of the metal particles, the formation and growth of carbon nanomaterials were occurred in the lower temperature region than that of using SUS304 substrates only.

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Synthesis and Properties of Fe-Ni Nano-sized Powders using Metal Nitrates (금속질산염을 이용한 Fe-Ni 나노분말의 제조 및 특성)

  • Joo, Min-Hee;Oh, Sung-Tag
    • Journal of Powder Materials
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    • v.16 no.3
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    • pp.191-195
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    • 2009
  • The calcination and hydrogen-reduction behavior of Fe- and Ni-nitrate have been investigated. $Fe_2O_3$/NiO composite powders were prepared by chemical solution mixing of Fe- and Ni-nitrate and calcination at $350^{\circ}C$ for 2 h. The calcined powders were hydrogen-reduced at $350^{\circ}C$ for 30 min. The calcination and hydrogen-reduction behavior of Fe- and Ni-nitrate were analyzed by TG in air and hydrogen atmosphere, respectively. TG and XRD analysis for hydrogen-reduced powders revealed that the $Fe_2O_3$/NiO phase transformed to $FeNi_3$ phase at the temperature of $350^{\circ}$. The activation energy for the hydrogen reduction, evaluated by Kissinger method, was measured as 83.0 kJ/mol.

Nonmonotonic Ordering of Lanthanon Nitrates in the Phosphine Oxide Extraction Systems (稀土類元素의 溶媒抽出의 不均一性)

  • C. T. Rhee
    • Journal of the Korean Chemical Society
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    • v.7 no.4
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    • pp.271-276
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    • 1963
  • The distribution ratio of lanthanon nitrates in the TBPO- and TOPO-toluene systems were studied radiometrically as a function of solvent, nitrate and atomic number(Z). The plots of log Kd vs. Z shows two straight lines which are crossing at Z = 63∼64. The solvent dependency was same for lighter and heavier lanthanons but nitrate dependency was different between the two parts.

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Study on Synthesis and Electromagnetic Properties of Ni- Zn Ferrite Sintered at Low Temperature (저온 소결용 Ni-ZN계 페라이트의 합성 및 전자기적 특성 연구)

  • Kim, Chul-Won;Koh, Jae-Gui
    • Korean Journal of Materials Research
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    • v.12 no.8
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    • pp.600-607
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    • 2002
  • The Ni-Zn synthetic ferrite were acquired from thermally decomposing the metal nitrates Fe(NO$_3$)$_3$.$9H_2$O, Zn($NO_3$)$_2$.$6H_2$O, Ni($NO_3$)$_2$. $6H_2$O, and Cu($NO_3$)$_2$. $3H_2$O at $150^{\circ}C$ for 24 hours and was calcined at $500^{\circ}C$. Each of those was pulverized for 3, 6, 9, and 12 hours in a steel ball mill and was sintered between $700^{\circ}C$ and $1,000^{\circ}C$ for 1 hour, and then their microstructures and electromagnetic properties were examined. We could make the initial specimens chemically bonded in liquid at the temperature as low as $150^{\circ}C$, by using the melting points less than $200^{\circ}C$ of the metal nitrates instead of the mechanical ball milling, then narrowed a distance between the particles into a molecular level, and thus lowed sintering temperature by at least $200^{\circ}C$ to$ 300^{\circ}C$. Their initial permeability was 50 to 400 and their saturation magnetic induction density and coercive force 2,400 G and 0.3 Oe to 0.5 Oe each, which were similar to those of Ni- Zn ferrite synthesized in the conventional process. In the graph of initial permeability vs frequencies, we could observe a $180^{\circ}C$rotation of the magnetic domain, which appears in a broad band of microwave near the resonance frequency.

Separation performances of a nanofiltration membrane for chlorides, nitrates and sulfates aqueous solutions

  • Wang, Da-Xin;Su, Meng;Wang, Xiao-Lin
    • Proceedings of the Membrane Society of Korea Conference
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    • 2004.05a
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    • pp.155-160
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    • 2004
  • Permeation experiments of a commercial nanofiltration membrane (nominated as ESNA 1) were carried out with aqueous solutions of various single salts, that is, five chlorides (NH$_4$Cl, NaCl, KCl, MgCl$_2$ and $CaCl_2$), three nitrates $(NaNo_3,\;Mg(No_3)_2\;and\;Ca(NO_3)_2)\;and\;three\;sulfates\;((NH_4)_2SO_4,\;Na_2SO_4\;and\;MgSO_4)$. The experimental results showed that (1) the permeate volume flux of the ESNA 1 membrane increased and decreased with the growth of the applied pressure and the feed concentration of salts, respectively. The real rejection of ESNA 1 membrane to most single salts increased with the growth of the permeate volume flux. (2) The reflection coefficients of ESNA 1 membrane to chlorides, nitrates and sulfates are 0.97, 0.96 and 0.99, respectively. The solute permeability of most salts except for magnesium and calcium salts increased with the growth of feed concentration. (3) The sequence of the rejections of ESNA 1 membrane to anions is $R({SO_4}^{2-})>R(CI)>R(NO_3)$ at the same feed concentration. While the sequence of the rejections to cations is cataloged into two cases: $R(Na^+)>R(K^+)>R(Mg^{2+})>R(Ca^{2+})$ at the concentration of 10 mol/$m^3$ and $R(Mg^{2+})>R(Ca^{2+})>R(Na^+)>R(K^+)$ at the concentration of 100 mol/$m^3$. The separation capability of a NF membrane is usually affected by the electrostatic effect and the steric-hindrance effect. In this case, the electrostatic effect is the major factor at low concentration and the steric-hindrance effect is the major factor at high concentration. Both the specific sorption and the hydration also reasonably influenced the separation performance of NF membrane to salts.

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Regression Studies of Dry Weight of Planktonic Biomass on Physico-chemical Parameters of Ponds with Special Reference to Fertilization

  • Mahboob, Shahid;Sheri, A.N.
    • Asian-Australasian Journal of Animal Sciences
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    • v.16 no.2
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    • pp.172-175
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    • 2003
  • The regression equations of dry weight of planktonic biomass upon physico-chemical characteristics of fifteen ponds in three replicates under the influence of artificial feed, broiler manure, buffalo manure, N:P:K (25:25:0) and a control pond was obtained after one year of experimental period by using stepwise regression method. Water samples from each of the ponds were analyzed daily. However, the average values were calculated on the basis of 15 day intervals designated as fortnight. In artificial feed supplemented pond the regression of average nitrates on dry weight of planktonic biomass accounted for 71.7% of the variation in biomass. In broiler manure fertilization pond the regression of total nitrogen on dry weight of planktonic biomass held it responsible for more than 74.6% of variation in biomass. In buffalo's manure fertilized pond more than 82% of the variations in biomass were due to total nitrogen. In case of N:P:K (25:25:0) treated pond 66% of the variation in the dry weight of planktonic biomass was due to average nitrates. The control pond showed the dependence of biomass on light penetration. This equation explained more than 62 percent of variation in biomass. Other variables also showed some contribution towards variation in biomass under all the treatments in these regression studies.

Preparation of NiO/YSZ Ultra-Fine Powder Composites Using Self-Sustaining Combustion Process (Self-Sustaining Combustion Process를 이용한 NiO/YSZ 초미세 복합분말 제조)

  • 김선재;정충환;김경호;김영석;국일현
    • Journal of the Korean Ceramic Society
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    • v.33 no.4
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    • pp.411-417
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    • 1996
  • Ultrafine NiO/YSZ (Yttria Stabilized Zirconia) powders were made by using a glycine nitrate process which is used as anode material for solid oxide fuel cells. The specific surface areas of synthesized NiO/YSZ powders were examined with controlling pH of a precursor solution and the content of glycine. The binding of glycine with metal nitrates occurring in the precursor solution was analyzed by using FTIR. The characteristics of synthesized powders were examined with X-ray diffraction(XRD) Brunauer Emmett Teller with N2 absorption. scanning electron microscopy (SEM). and transmission electron microscopy (TEM). Ultrafine NiO/YSZ powders of 15-18 m2/g were obtained through GNP when the content of glycine was controlled to 1 or 2 times the stoichiometric ratio in the precursor solutions. Strongly acid precursor solution increased the specific surface area of the synthesized powders. This is suggested to be the increased binding of metal nitrates and glycine under a strong acid solution of pH=0.5 that lets glycine consist of mainly the amine group of {{{{ { NH}`_{3 } ^{+ } }}. After sintering and reducing treatment of NiO/YSZ powders synthesized by GNP the Ni/YSZ pellet showed ideal microstructure where very fine Ni particles of 3-5 ${\mu}{\textrm}{m}$ were distributed uniformly and fine pore around Ni metal particles was formed. leading to anincrease of the triple phase boundary among gas Ni and YSZ.

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Changes in Microbiological and Chemical Properties of Natural Water with the Storage Time and Temperature (시판 먹는 샘물의 저장 기간 및 온도에 따른 세균학적 및 화학적 품질 변화)

  • 박신인;이왕규;조윤정
    • Journal of Food Hygiene and Safety
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    • v.12 no.1
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    • pp.55-62
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    • 1997
  • This study was carried out to investigate the microbiological and chemical properties of natural water during storage. The water samples were taken at the time of purchase and the opened bottles and unopened bottles stored at the temperature of 4$^{\circ}C$, 18$^{\circ}C$, and 3$0^{\circ}C$. The bacterial content normally rose to 2.06$\times$102 CFU/$m\ell$ for the unopened bottles and 2.91$\times$102 CFU/$m\ell$ for the opened bottles after 2 weeks of storage, and 1.21$\times$102 CFU/$m\ell$ and 2.64$\times$102, respectively, after 24 weeks of storage. The number of viable cells of bacteria peaked more rapidly at the storage temperature of 3$0^{\circ}C$ than 18$^{\circ}C$. But the total samples were found to be negative for coliforms test during the study period. The average range of pH value was from 7.39 to 7.76. The results showed that the nitrates and chlorides satisfied the Korea Drinking Water Quality Standards during the storage period of 24 weeks. However, the undesirable changes of the taste and odor were detected within 2 weeks and 3 weeks, respectively.

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