• Journal of Animal Environmental Science
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• v.4 no.2
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• pp.137-147
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• 1998

This study was carried out to find deodorization effect of swine-slurry by addition of phototrophic bacteria(PTB). The pilot-scale reactors operation conditions was designed by the inoculum amounts of PTB and light-conditions. Treatment conditions was divided into 3 types; 106 MPN/ml$.$Dark(T-1), 108 MPN/ml$.$Dark(T-2), 108 MPN/ml$.$Natural light(T-3). The changes of the concentration of volatile fatty acids(VFAs), hydrogen sulfide(H2S), ammonia (NH3) and odor intensity were analyzed during the treatment period(35 days). From results of this study, the maximum intensity of odor in the headspace of the reactor T-1 was 4.82 and T-2, T-3 was 2.63, respectively. In swine-slurry of reactors used, it almost took 10 days until to be stabilized with solid and liquid phase. Intensity of odor in headspace was mainly derived from the liquid phase. The PTB inoculum method to swine-slurry was very effective in reduction of VFAs, H2S and Sulfate-reducing bacteria(SRB) concentration. Expecially, It was interested in reverse growth behaviour of SRB and PTB in these conditions.

• Economic and Environmental Geology
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• v.25 no.3
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• pp.225-232
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• 1992

The hydrothermal alteration is evaluated using multicomponent equilibrium calculations with the program CHILLER for the reactions between hydrothermal water and rhyolite at the temperature of $300^{\circ}C$ and pressure of 500 bars. The chemical-reaction model on the depositional processes of the sericitite confirms that the hydrothermal water-rock interaction(hydrothermal alteration) is the main mechanism of the sericitite formation. The principal change in the aqueous phase during the reaction is the pH increase. Overall trends for the major species are the increase in total molalities of K, Ca, $SiO_2$, Al, Mg, Fe, Na, and sulfide in solid phase with hydrothermal water-rhyolite reaction and the decrease of them in aqeous solution by precipitation of hydrothermal products. Quartz and sericite are the first minerals to form. The sequence of minerals to precipitate following them is chlorite, epidote, pyrite and microcline as water/rock ratio decreases. Although calculated results cannot duplicate the complexities of natural hydrothermal alteration, the calculation provides thermodynamic constraints on the natural process. The calculation results resemble those of experimental studies. Sericitite forms where pH decreases and water/rock ratio increases.

• Journal of the Korean Ceramic Society
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• v.53 no.5
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• pp.568-573
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• 2016

We explore the crystalline structure and phase transition of lithium thiophosphate ($Li_7P_3S_{11}$) solid electrolyte using electron microscopy and X-ray diffraction. The glass-like $Li_7P_3S_{11}$ powder is prepared by the high-energy mechanical milling process. According to the energy dispersive X-ray spectroscopy (EDS) and selected area diffraction (SAD) analysis, the glass powder shows chemical homogeneity without noticeable contrast variation at any specific spot in the specimen and amorphous SAD ring patterns. Upon heating up to $260^{\circ}C$ the glass $Li_7P_3S_{11}$ powder becomes crystallized, clearly representing crystal plane diffraction contrast in the high-resolution transmission electron microscopy image. We further confirm that each diffraction spot precisely corresponds to the diffraction from a particular $Li_7P_3S_{11}$ crystallographic structure, which is also in good agreement with the previous X-ray diffraction results. We expect that the microscopic analysis with EDS and SAD patterns would permit a new approach to study in the atomic scale of other lithium ion conducting sulfides.

• Current Photovoltaic Research
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• v.1 no.2
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• pp.109-114
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• 2013

$Cu_2ZnSnS_4$ (CZTS) nanoparticles were synthesized by a solvothermal method using copper (II) acetate, zinc acetate, tin chloride, and sulfur in diethylenetriamine solvent. Binary sulfide particles such as CuS, ZnS, SnS, and $SnS_2$ were obtained at $180^{\circ}C$; single-phase CZTS nanoparticles were obtained at $280^{\circ}C$. CZTS nanoparticles with spherical shape and grain size of 40 to 60 nm were obtained at $280^{\circ}C$. In the middle of 180 and $280^{\circ}C$, CZTS and ZnS phases were found. The time variation of reaction at $280^{\circ}C$ revealed that an amorphous state formed first instead of binary phases and then the amorphous phase was converted to crystalline CZTS state; it is different reaction path way from conventional solid-state reaction path of which binary phases react to form CZTS. CZTS films deposited and annealed from single-phase nanoparticles showed porous microstructure and poor adhesion. This indicates that a combination of CZTS and other flux phase is necessary to have a dense film for device fabrication.

• Bulletin of the Korean Chemical Society
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• v.28 no.12
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• pp.2293-2298
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• 2007

In this study, a dithizone extraction technique involving purge & trap GC-MS was developed for the determination of methylmercury in biological samples, especially blood and fish. After alkaline digestion, methylmercury in biological samples was extracted into dithizone and back-extracted into aqueous sulfide solution. The extracted methylmercury was converted to the volatile ethyl derivative, purged and trapped onto a solid-phase collection medium, and then introduced into the GC-MS system. The determined MDLs of the established method were 0.9 ng·g?1 for biological samples and its accuracy and precision were found to be 93% and 3.8%, respectively. The method was validated by analysis of CRMs such as SRM 966, BCR 463 and IAEA 407 and all analytical results were within certified ranges with average RSDs of less than 6%. The analytical results of field-sampled fish also showed that the method can be successfully used as an alternative for commonly used distillation method followed by GC-CVAFS detection.

• Korean Journal of Materials Research
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• v.12 no.7
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• pp.568-572
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• 2002

Plasma sulfnitriding technology was employed to harden the surface of SKD61 steel. The plasma sulfnitriding was performed with 3 torr gas pressure at $580^{\circ}C$ for 20 hours. Plasma sulfnitriding resulted in the formation of very thin $2-3\mu\textrm{m}$ FeS sulfide layer on top of $15-20\mu\textrm{m}$ compound layer, which consisted of predominantly $\varepsilon$- $Fe{2-3}$ N and a second phase of $\Upsilon'-Fe_4$N. In comparision with plasma nitriding treatment, plasma sulfnitriding treatment showed better surface roughness and corrosion resistance due to the presence of the thin FeS layer. which coated microvoids and microcracks on top of the nitrided layer. It was also found that plasma sulfnitrided sample showed better wear resistance due to the presence of the thin FeS layer which acted as a solid lubricant.

• Journal of the Mineralogical Society of Korea
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• v.26 no.1
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• pp.9-18
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• 2013

In order to optimize the gold leaching process from refractory sulfide concentrate, a chlorine-hypochlorite solution with varying concentrations and temperatures were applied to salt-roasted concentrate. The concentrate consisted of pyrite, chalcopyrite, and galena, which were turned into hematite through air-roasting at $750^{\circ}C$. Also these concentrates were changed into hematite and nantokite (CuCl)) through salt (NaCl)-roasting at $750^{\circ}C$. The results of the gold leaching experiments showed that the best gold leaching parameters were obtained when the hydrochloric acid-sodium hypochlorite mix was at a ratio of 1 : 2, the added concentration was 1.0 M concentration, the pulp density was 1.0%, and the leaching was done at a $60^{\circ}C$ leaching temperature. The leaching rate for gold was much greater in the roasted concentrate than in the raw concentrate. The leaching rate was greater in the salt-roasted concentrate than in the plain roasted concentrate too. From XRD analysis, quartz was found in the salt-roasted concentrate and in the solid residue from the chlorine-hypochlorite leaching solution at $60^{\circ}C$.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.1
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• pp.116-122
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• 2012

Volatile flavor compounds derived from four black garlic extracts purchased in a local market were analyzed for the purpose of quality assessment. A total of 68 compounds was detected in samples using solid phase microextraction (SPME)/GC/MSD, and they were mainly sulfur-containing compounds, including three unknown compounds (21), aldehydes (10), furans (7), alcohols (6), aromatic compounds (7), ketones (4), acids (4), nitrogen-containing compounds (3), esters (2), and miscellaneous compounds (4). 2,6-Dimethyl-4-heptanone having a fruity-sweet odor was the most abundant in all of the samples. Six sulfur-containing compounds including allyl sulfide, 4-methyl-1,2,4-thiazole, 1,3,5-trithiane, unknown I (RI 1564), unknown II (RI 1565), and unknown III (RI 1613) were detected in all of the samples and appeared to contribute to the garlic-like odor. Particularly, three aldehydes (3-methylbutanal, benzaldehyde, phenylacetaldehyde), four furans (furfural, 2-acetylfuran, 5-methyl-2-furfural, furfural alcohol), and others (2,6-dimethylpyrazine, acetic acid) formed through a Maillard reaction during garlic aging were detected in all of the samples, and they contributed to the characteristic burnt, sweet, and sour flavors of black garlic extracts.

• Korean Journal of Food Science and Technology
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• v.51 no.4
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• pp.324-329
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• 2019

Volatile flavor compounds of radish fermented by lactic acid bacteria were extracted using solid-phase microextraction (SPME) and analyzed by gas chromatography-mass spectrometry (GC-MS). A total of 45 volatile flavor compounds were identified. The volatile flavor compounds in unfermented radish mostly consisted of sulfur-containing compounds (95.85%) and aldehydes (2.61%). While the composition ratio of volatile flavor compounds in radish fermented for two days changed to sulfur-containing compounds (75.53%) and acids (11.12%). As the fermentation period was increased, the contents of dimethyl disulfide, dimethyl trisulfide, diallyl sulfide, diallyl disulfide, and diallyl trisulfide, which have unique garlic and scallion flavor, decreased, and acetic acid and 1-hexanol, which have a sour and fruity flavor, increased. These changes in volatile flavor compounds seemed to have affected the flavor characteristics of fermented radish.

• Journal of Korean Society for Atmospheric Environment
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• v.23 no.1
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• pp.39-49
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• 2007

In this study, the performance characteristics of solid phase microextraction (SPME) were investigated for three major odorous groups that consist of 10 individual compounds ([1] volatile organic compounds (VOC): benzene, toluene, p-xylene and styrene, [2] reduced sulfur compounds (RSC): hydrogen sulfide, methyl mercaptan, dimethylsulfide (DMS), dimethyldisulfide (DMDS), and carbon disulfide, and [3] amine: trimethylamine (TMA)). For the purpose of a comparative analysis, two types of SPME fiber ([1] polidimethylsiloxane/divinilbenzene (P/D) and [2] $Carboxen^{TM}$/polidimethylsiloxane (C/P)) were test ε d against each other for a series of standards prepared at different concentration levels (100, 200, and 500 ppb). To compare the analytical performance of each fiber, all standards were analyzed for the acquisition of calibration data sets for each compound. The results of P/D fiber generally showed that its calibration slope increased as a function of molecular weight across different VOCs; however, those of C/P fiber showed a fairly reversed trend. Besides, we confirmed that the application of SPME is limited to many sulfur compounds; only two compounds (DMS and DMDS) are sensitive enough to draw calibration results out of SPME. The calibration data for RSC show generally enhanced slop values for C/P relative to P/D fiber. However, in the case of TMA, we were not able to find a notable difference in their performance.