• Proceedings of the KIEE Conference
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• 2004.07e
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• pp.55-57
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• 2004

$HgGa_{2}S_{4}Co^{2+}$ single crystal were grown by the chemical transport reaction(CTR) method. In the optical absorption spectrum of the $HgGa_{2}S_{4}Co^{2+}$ single crystal measured at 298K, three groups of impurity optical absorption peaks consisting of three peaks, respectively, were observed at 673nm, 734nm, and 760nm, 1621nm, 1654nm, and 1734nm, and 2544nm, 2650nm, and 2678nm. At 10K, the three peaks(673nm, 734nm, and 760nm) of the first group were split to be twelve peaks. These impurity optical absorption peaks are assigned to be due to the electronic transitions between the split energy levels of $Co^{2+}$ sited in the $S_4$ symmetry point.

• Bulletin of the Korean Chemical Society
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• v.23 no.2
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• pp.286-290
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• 2002

Hydrogen atom production channels from photodissociation of benzene, phenylacetylene, and benzaldehyde at 243 nm have been investigated by detecting H atoms using two photon absorption at 243.2 nm and induced fluorescence at 121.6 nm. Translational energies of the H atoms were measured by Doppler broadened H atom spectra. By absorption of two photons at 243 nm, the H atoms are statistically produced from benzene and phenylacetylene whereas the H atoms from the aldehyde group in benzaldehyde are produced from different pathways. The possible dissociation mechanisms are discussed from the measured translational energy releases.

• Applied Chemistry for Engineering
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• v.23 no.1
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• pp.23-27
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• 2012

To make synthetic liquid fuel from biomass such as wood pellet, energy crop and so on, a biomass to liquid (BTL) process by using a biomass gasifier with Fisher-Tropsch (FT) reaction was developed. However $H_2S$, COS and $CO_2$ in syngas from biomass gasifiers resulted in a decrease of the conversion efficiency and the deactivation of the catalyst. To remove acid gases in syngas, a lab-scale methanol absorption tower was developed and the removal characteristics of acid gases were investigated. The methanol absorption tower efficiently removed $H_2S$ and COS with a removal of $CO_2$, so it could be useful process for the BTL process.

• Bulletin of the Korean Chemical Society
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• v.28 no.11
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• pp.2089-2092
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• 2007

Tantalum-containing metal oxides, well known for their efficiency in water splitting and H2 production, have never been used in visible light driven photodecomposition of H2S and H2 production. The present work is an attempt in this direction and investigates their efficiency. A mixed metal oxide, ZnFe2Ta2O9, with the inclusion of Fe2O3 to impart color, was prepared by the conventional ceramic route in single- and double-calcinations (represented as ZnFe2Ta2O9-SC and ZnFe2Ta2O9-DC respectively). The XRD characterization shows that both have identical patterns and reveals tetragonal structure to a major extent and a minor contribution of orthorhombic crystalline system. The UV-visible diffuse reflection spectra demonstrate the intense, coherent and wide absorption of visible light by both the catalysts, with absorption edge at 650 nm, giving rise to a band gap of 1.9 eV. Between the two catalysts, however, ZnFe2Ta2O9-DC has greater absorption in almost the entire wavelength region, which accounts for its strong brown coloration than ZnFe2Ta2O9-SC when viewed by the naked eye. In photocatalysis, both catalysts decompose H2S under visible light irradiation (λ ≥ 420 nm) and produce solar H2 at a much higher rate than previously reported catalysts. Nevertheless, ZnFe2Ta2O9-DC distinguishes itself from ZnFe2Ta2O9-SC by exhibiting a higher efficiency because of its greater light absorption. Altogether, the tantalum-containing mixed metal oxide proves its efficient catalytic role in H2S decomposition and H2 production process also.

• YAKHAK HOEJI
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• v.29 no.4
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• pp.220-222
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• 1985

Rifampicin reacts with cupric ion to produce rifampicin-Cu(II) chelate (2:1) at pH 6.5, which can be extracted with methylisobutylketone (MIBK). Therefore, rifampicin can be quantitatively, determined by measuring the quantity of Cu(II) in the organic phase by atomic absorption spectrophotometry. Because higher absorbance ratio was obtained in pH 6.0~7.0, buffer solution at pH 6.5 was used in this measurement. Linear relationship was found between absorbance and concentration in the range of 1.0~4.0${\times}10^{-4}M$. This method might be applicable to the determination of rifampicin in the preparations.

• Current Photovoltaic Research
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• v.4 no.3
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• pp.93-97
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• 2016

Light-emitting chromophores have been separated from silica spheres modified the surface with 3-(trimethoxysilyl)propylmethacrylate (TMSPM). The photoluminescence characteristics of the chromophores were investigated with various excitation wavelengths. The TMSPM was attached to the surface of silica spheres at $75^{\circ}C$. Large number of round shaped particles of the TMSPM was on the surface of silica spheres after 3 h reaction. The TMPSM was completely covered on the surface of the spheres after 6 h reaction. The surface modified silica spheres were soaked into acetone and stored for 20 days at ambient condition. The solution color slowly changed from light yellow to deep yellow with the increase of the storing time. The FTIR absorption peaks at 3348, 2869, 2927, 1715, 1453/1377, 1296, and $1120cm^{-1}$ represent C-OH, $R-CH_3$, $R_2-CH_2$, -C=O, C-H, C=C-H, and Si-O-Si absorption, respectively. The FTIR absorption peak at $1715cm^{-1}$ representing the ester -C=O stretching vibration for silica spheres stored for 20 days was increased compared with the spheres without aging. The UV-visible absorption peaks were at 4.51 eV (275 nm) and 3.91 eV (317 nm). There were two luminescence peaks at 2.51 eV (495 nm) and 2.25 eV (550 nm). The emission at 2.51 eV was dominant peak when the excitation energy was higher than 2.58 eV, and emission at 2.25 eV became dominant peak when the excitation energy was lower than 2.58 eV.

• Journal of Sericultural and Entomological Science
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• v.41 no.2
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• pp.116-121
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• 1999

This study was aimed to explain the essence of Hydroxylammonium hydrochloride(H.A.) effect on degummed silk fiber increasing the colour sites due to oxime generating reaction. H.A. in aqueous solution caues to increase the amount of [H+] and reduce pH values as the concentration of H.A. increases. The rate of [H+] absorption of silk fiker in acidic solution differs on the basic of solution pH and shows a specific uptake in each pH, the lower the pH of solution, the higher the amount [H+] absorption. The pH of solution after treating of silk fiber in H.A. and HCl, showed more remaining [H+] in H.A. solution due to [H+] releasing under the procedure of oxime production. Also it was revealed that in higher concentration of H.A. the reaction for oxime fixation in silk fiber carried out stonger and as a result the bigger gap with acid uptake curve appeared. FT-IR analysis of silk fiber treated with H.A. revealed the creating of intermolecular H-bond at the 2,981-2.930 cm-1, which was not appeared for nontraeted silk fibers and shows H-bond between N-OH group in oue chain and C=) group in another chain of silk protein. Colourimetry of dyed silk fiber after H.A. tratment showed that the silk fiber treated with the high concentration of H.A. compare to low concentration, absorbed more dyeing molecules and so Showed less percontage of Whiteness.

• Proceedings of the Materials Research Society of Korea Conference
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• 2009.05a
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• pp.34.2-34.2
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• 2009

The silver sulphide (Ag2S) thin films have been chemically deposited from an alkaline medium (pH 8 to 10) by using a silver nitrate and thiourea as a Ag and S ion precursor sources. Ethylene Damine tetraacetic acid (EDTA) was used as a complexing agent. The effect of annealing atmosphere such as Ar, N2+H2S and O2 on the structural, morphological and optical properties of Ag2S thin films has been studied. The annealed films were characterized by using X-ray diffraction (XRD), scanning electron microscopy (SEM) and optical absorption techniques for the structural, morphological, and optical properties, respectively. XRD studies reveal that the as-deposited thin films are polycrystalline with monoclinic crystal structure, is converted in to silver oxide after air annealing. The surface morphology study shows that grains are uniformly distributed over the entire surface of the substrate. Optical absorption study shows the as-deposited Ag2S thin films with band gap energy of 0.92eV and after air annealing it is found to be 2.25 eV corresponding to silver oxide thin films.

• Current Photovoltaic Research
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• v.7 no.2
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• pp.29-32
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• 2019

Large band gap attenuation of CdS nanoclusters in hybrid sol gel matrix comprised of 3-(trimethoxysilyl)propyl methacrylate (TMSPM), 15 wt. % zirconium, and various amounts of cadmium acetate was observed after $H_2S$ exposure. Hybrid sol gel matrixes were prepared by hydrolysis and condensation reactions. The sol gels contained with various amount of cadmium acetate were spin coated to glass substrates and exposed to $H_2S$ gas. The UV-visible absorption peaks were shifted toward blue with increasing the amount of CdS nanoclusters and were shifted to the red after thermal process. Significant amount of -OH absorption peaks were reduced after thermal process. Strong room temperature photoluminescence (PL) of CdS nanoclusters was observed after exposing to $H_2S$ gas. The PL intensity increased for several minutes and slowly decreased thereafter. The luminescence peaks were continuously shifted toward blue as the time passed. Extraordinary Stokes shift (approximately 160 nm) was observed.

• Journal of the Korean Solar Energy Society
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• v.24 no.1
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• pp.53-61
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• 2004

Absorption potential of desiccant solution significantly decreases after absorbing moisture from humid air, and a regeneration process requires a great amount of energy to recover absorption potential of desiccant solution. In an effort to develop an efficient solar water heater, this study examines a regeneration process using hot water obtained from solar water heater to recover absorption potential by evaporating moisture in the liquid desiccant. In this paper, a solar absorption dehumidifying system with solar water heater is suggested to save the electricity for operating an air conditioner. LiGl(lithium chloride) solution was adopted as a liquid desiccant in the proposed system, and hot water obtained from the solar water heater was used for regenerating the liquid desiccant. As a result, it was clear that the dilute LiCl solution could be regenerated by hot water, and the regeneration rate depends mostly on temperature level of liquid desiccant. The regeneration rates were about 2.4kg/h with $40^{\circ}C$, 4.0kg/h with $50^{\circ}C$, and 6.2kg/h with $60^{\circ}C$ of hot water respectively.