• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.17 no.9
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• pp.1001-1005
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• 2004

Rye-sensitized solar cell (DSSC) is a new class of solar cell, which consists of nanoporous TiO$_2$ electrode, dye-sensitizer, electrolyte, and counter electrode. Such cell is operated in sunlight via the principle of photosynthetic electrochemistry. In order to obtain the good dispersion of nano size TiO$_2$ particles In slurry, the pH of solvent, the sort and quantify of solvent additive and the quantity of surfactant were adjusted. As results, the lower the pH of solvent was the lower the viscosity of the slurry became. The addition of ethylene glycol and propylene glycol to dilute HNO$_3$ brought about the lowering of viscosity and the enhancement of stability in slurry. The addition of surfactant lowered the viscosity of slurry. It was possible to obtain the homogeneous and uniformly dispersed mesoporous TiO$_2$ film using the dilute HNO$_3$ solvent of pH 2 with the addition of ethylene glycol and neutral surfactant. DSSC was assembled with TiO$_2$ electrode and Pt electrode, and its photoelectric property was measured using the monochromatic wavelength in the rangee of 350∼700 nm.

• Proceedings of the KSME Conference
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• 2000.11b
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• pp.168-173
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• 2000

Flame aerosol synthesis technology refers to the formation of fine particles from gases in flame and is widely used in practical materials processing. In this paper, an experimental investigation was performed on growth of the silica particles that were generated in $H_2/O_2$ Diffusion Flame by the direct injection or TEOS using Electro-spraying method. in this flame aerosol synthesis, four main parameters or nos interaction (flame temperature, residence time or particle in flame, TEOS flow rate, applied voltage) for particle generation and growth was investigated along the axial direction above the burner. A fairly monodisperse non-aggregated particles were successfully obtained.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.16 no.1
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• pp.34-41
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• 2004

The chemical heat pump based on the Dehydration/Hydration process with a MgO/$H_2O$ system has been researched. The reactor bed could be expected to store the heat around 200∼37$0^{\circ}C$ by the dehydration reaction and to release the heat around 100∼16$0^{\circ}C$ by the hydration reaction under the heat amplification mode operation. The heat output rate of the heat pump system was evaluated using the experimentally determined parameters. The results show that 6∼50 W/kg of heat output and 0.5∼0.8 of heat recovery ratio are attainable. The heat pump will be applicable for a load leveling in a co-generation system by chemical storage of surplus heat at low heat demand and by supplying heat in the peak load period.

• Journal of the Korean Chemical Society
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• v.17 no.6
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• pp.424-427
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• 1973

Durch hydrothermale Behandlung wurde das Mineral Duttonit von einem rosafarbenen 4-wertigenvanadin Aquoxid($VO_2{\cdot}H_2O$) synthesiert und davon wurden Einkristallu gezuchtet. Das monokline hydroxid kristallisiert in der Raumgruppe $C_2/c$. Es befinden sich vier formeleinheiten in der Einheitszelle. Die Abmessungen der Elementarzelle betragen; a = 8.78 ${\AA}$; b = 3.94 ${\AA}$; c = 5.95 ${\AA}$; ${\beta}=90^{\circ}$41'.

• Bulletin of the Korean Chemical Society
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• v.16 no.12
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• pp.1176-1179
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• 1995

1H NMR spectra of pyridine, α-, β-, and γ-picoline coordinated to the paramagnetic heteropolyanion [Ni3(PW9O34)2]12- (P2Ni3) are reported. NMR lines are assigned to [Ni3(ptl)n(PW9O34)2]12- (n=1, 2 or 3; ptl=pyridine-type ligand) on the basis of their [P2Ni3]/[ptl] dependence. The formation constants for γ-picoline complexes at 25 ℃ are K1=80, K2=610, and K3=190 L mol-1. The monopicoline complex has greater affinity for γ-picoline than P2Ni3. A degradation product, [Ni2(WO2)(PW9O34)2]12-, was also identified at low pH by measuring the NMR spectrum of pyridine coordinated to it. The isotropic NMR shifts come mainly from the contact interaction due to σ-electron delocalization.

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2003.05a
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• pp.685-688
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• 2003

BaTiO$_3$ 분말을 Ba(OH)$_2$ㆍ8$H_2O$와 아나타제형의 TiO$_2$ㆍx$H_2O$를 이용하여 수열합성법에 의해 제조하였다. Autoclave 반응기를 이용한 본 실험의 경우, BaTiO$_3$ 분말을 생성하기 위해 반응온도, 용질의 농도 등과 같이 BaTiO$_3$ 합성에 관여하는 반응변수를 변화시켜, 각각의 실험조건이 어떠한 영향을 미치는지를 조사하였다 수열합성법에 의해 합성된 BaTiO$_3$의 전화율은 온도와 농도 증가에 따라 높아지는 현상을 보였으며, 열역학적으로 계산된 최대 전화율에 접근하였다. 또한 반응온도와 농도의 증가에 의해 생성된 BaTiO$_3$는 균일한 입도 분포와 구형에 가까운 형상을 나타내었다. 따라서 농도를 높이는 조건이 전화율과 생산성을 모두 높일 수 있는 방법이라는 것을 확인할 수 있었다.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.4
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• pp.402-408
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• 2005

This investigation aimed at selecting the optimum catalyst and reaction conditions used in Fenton oxidation for landfill leachate treatment and was carried out at ambient temperature using a lab-scale experiment. The investigation led to the following results: 1) The optimum pH and dose for each iron catalyst were as follows: $Fe^{2+}\;=\;1,200\;mg/L$, $H_2O_2\;=\;1,200\;mg/L$, initial pH=3.0; $Fe^{3+}\;=\;1,200\;mg/L$, $H_2O_2\;=\;1,500\;mg/L$, initial pH=4.5; $Fe^0\;=\;1,200\;mg/L$, $H_2O_2\;=\;900\;mg/L$, initial pH=4.0, respectively. 2) The progress of Fenton oxidation could be instrumentally monitored by measuring redox potential evolution during leachate oxidation, thus, indicating the possibility of an on-line process monitoring. 3) A simple acid-base titration of Fenton-treated leachate proved that a relevant fraction of by- products formed during the treatment was made of acidic compounds in the optimum reaction condition for each catalyst used, thus demonstrating that the higher the extent of Fenton oxidation the greater was the amount of acids formed. 4) With the aim of selecting the optimum catalyst among $Fe^0$, $Fe^{2+}$ and $Fe^{3+}$, removal efficiency of each parameter in the optimum reaction conditions was considered. Although $Fe^{3+}$ was higher than other catalysts($Fe^0$, $Fe^{2+}$) in removal efficiency, $Fe^0$ was a optimum catalyst with a view of cost effectiveness.

• Journal of the Korean Ceramic Society
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• v.27 no.5
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• pp.668-676
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• 1990

Glass in the ZrO2-SiO2 system containing up to 30mol% ZrO2 were prepared by heating the gel made from the mixed solutions of Zr(OC3H7)4 and partial hydrolysed Si(OC2H5)4. As a result, the monolith gel was made from the HCl and water content as 2.7$\times$10-3 and 8 molar ratio to alkoxide and drying temoperature as 4$0^{\circ}C$. Heating rate of dry gel maintained under 0.5$^{\circ}C$/min and heating at a temperature as 90$0^{\circ}C$ was found to be for making the transparent glass.

• Korean Journal of Microbiology
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• v.24 no.3
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• pp.329-334
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• 1986

The bacteria capable of utilizing polyethylene glycol(PEG) 6,000 as a sole carbon source were isolated from soil and sewage water connected to factory area. The isolate designated as EL-033 had high biodegradability on PEG 6,000, and was identified as Micrococcus sp. Micrococcus sp. EL-033 could grow on and degrade di-, tri-, tetraethylene glycols and PEGs with molecular weight up to 6,000 and very slowly stilize PEG 20,000 as sole carbon source, but not degrade ethylene glycol. The growth rate of isolate was increased in the higher molecular weight PEGs. The optical culture medium was established to be as follow: PEG 6,000, 0.2%(w/v); $K_2HPO_4$, 0.1%; $NaH_2PO_4{\cdot}12H_2O,\;0.1%\;:\;MgSO_4{\cdot}7H_2O$, 0.05%; polypeptone, 0.1% in distilled water, pH7.5. About 90% of PEG 6,000 was degraded in exponential phase of 48h culture and PEG 6,000 was completely degraded during 72h.

• Advances in environmental research
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• v.5 no.3
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• pp.189-200
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• 2016

This study aimed at advanced oxidation of hetero tri-functional reactive dye Acid orange 7 using photo-Fenton conditions in a lab-scale experiment. Decolourisation of Acid Orange 7 dye by Fenton's process was dependent on concentration of Hydrogen peroxide, Ferrous sulphate, pH, and contact time. A $2^3$ factorial design was used to evaluate the effects of these key factors: pH, Fe(II), and $H_2O_2$ concentration, for a dye concentration of 50 mg/L with COD of 340 mg/L at pH 3.0. The response function was removal of colour under optimised conditions; pH 3.0, [Fe(II)] 40.83 mg/L, [$H_2O_2$] 4.97 mmol/L; 13.6 min. of treatment resulting in 100% colour removal. The final COD of treated wastewater was nil suggesting that AOP is a potentially useful process of color removal and dye degradation/mineralisation of effluent having AO7. Minimum contact time for complete decolourisation was at 5 mmol/l $H_2O_2$ concentration. Increase in $FeSO_4$ (mg/l) concentration resulted in decrease of time for complete decolourisation. Box-Behnken Design was used to optimize the process variables. Maximum and minimum levels of pH (3-5), $H_2O_2$ (4-6 mmol/l), $FeSO_4$ (30-46 mg/l) and contact time (5-15 minutes) were used. The statistical analysis revealed a value of 0.88 for coefficient of regression ($R^2$) indicating a good fit of model. Calculated F-value was found higher than the tabulated value confirming to significance of the model. Based on student's t-test, Ferrous sulphate, pH, and contact time have a positive effect on the percent decolourisation of Acid Orange 7.