• 한국축산시설환경학회지
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• 제4권2호
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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.

• 자원환경지질
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• 제25권3호
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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.

• 한국세라믹학회지
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• 제53권5호
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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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• 제1권2호
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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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• 제28권12호
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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.

• 한국재료학회지
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• 제12권7호
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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.

• 한국광물학회지
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• 제26권1호
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• pp.9-18
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• 2013

저항성 황화광물 정광으로부터 최적의 gold를 용출시키기 위하여 염소-차아염소산 용액과 다양한 온도와 농도를 소금소성정광에 적용하였다. 정광은 황철석, 황동석, 방연석으로 구성되었으며, 공기 중에서 $750^{\circ}C$ 소성처리하자 적철석으로 변환되었고, 소금으로 소성처리하자 적철석과 난토카이트(nantokite, CuCl)으로 변환되었다. 다양한 변수로 용출실험을 수행한 결과, 염소-차아염소산 나트륨 혼합 비율 1 : 2에서, $FeCl_3$ 첨가량 1.0 M에서, 광액농도 1.0%에서, 그리고 용출온도 $60^{\circ}C$에서 최대의 금 용출율을 얻었다. 금 용출율은 정광에서보다 소성정광에서 더 높게 용출되었고, 소성정광에서보다 소금소성정광에서 더 높게 용출되었다. XRD 분석 결과, 소금소성정광에서, 그리고 $60^{\circ}C$의 염소-차아염소산 용출용액 고체 잔유물에서 석영이 관찰되었다.

• 한국식품영양과학회지
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• 제41권1호
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• pp.116-122
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• 2012

흑마늘은 일정기간 마늘의 자체 성분과 효소 등에 의해 숙성되어 진한 흑갈색으로 변한 것으로 추출액과 같은 가공형태로 시중에 많이 유통되고 있으나 관능적 품질평가에 대한 연구는 아직 미흡한 실정이다. 본 연구에서는 국내 흑마늘 제품의 산지별에 따른 흑마늘추출액 4종(A, B, C, D)을 선정하여 관능적 요소 중 가장 중요한 휘발성 향기성분을 분석하여 제품의 품질에 대한 기초자료로 활용하고자 하였다. 시판 흑마늘추출액의 휘발성 향기성분을 분석한 결과, 총 68종으로 함황화합물류 21종, 알데히드류 10종, 퓨란류 7종, 알콜류 6종, 방향족화합물 7종, 케톤류 4종, 산류 4종, 질소화합물 3종, 에스테르류 2종 및 기타 4종이 검출되었다. 흑마늘추출액 모든 시료에서 fruit-sweet향의 2,6-dimethyl-4-heptanone이 높은 함량 검출되었다. 함황화합물에서는 6종, allyl sulfide, 4-methyl-1,2,4-thiazole, 1,3,5-trithiane, unknown I(RI 1564), II(RI 1565), III(R I1613)이 전 시료에서 높은 함량 검출되었으며, 마늘향기성분에 관여할 것으로 사료된다. 또한 Maillard 반응에 의해 형성되어지는 것으로 알려진 3종의 알데히드류(3-methylbutanal, benzaldehyde, phenylacetaldehyde)와 4종의 furan류(furfural, 2-acetylfuran, 5-methyl-2-furfural, furfuryl alcohol), 2,6-dimethyl pyrazine, acetic acid가 모든 시료에서 높은 함량으로 검출되었으며, 이들 향기성분들은 시판 흑마늘추출액의 휘발성성분에 burnt, sweet, sour한 특징적인 냄새에 기여할 것으로 사료되었다.

• 한국식품과학회지
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• 제51권4호
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• pp.324-329
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• 2019

무 발효물의 발효기간에 따른 휘발성 향기성분을 SPME를 이용하여 추출하고 GC-MS로 분석하였다. 총 46종의 휘발성 향기 성분이 검출되었으며, 이들 중 함황화합물의 함량이 가장 높았다. 발효 전(발효 0일차) 휘발성 향기성분의 조성 비율을 보면 함황화합물(95.85%)과 알데하이드(2.61%)가 대부분을 차지했고, 발효 후(발효 2일차) 휘발성 향기성분의 조성 비율은 함황화합물(75.53%), 산(11.12%), 알코올(8.44%) 및 알데하이드(1.48%)으로 구성되어 변화가 큼을 알 수 있었다. 발효 후 함황화합물의 총 함량은 18,074.7 ng/g에서 2,996.2 ng/g으로 가장 크게 감소하였고, 이 성분 중 원재료의 주 성분으로 알려져 있는 dimethyl disulfide, dimethyl trisulfide, diallyl sulfide, diallyl disulfide와 diallyl trisulfide의 함량이 발효 기간이 증가함에 따라 크게 감소하는 경향을 보였다. 또한 이 성분들은 자극적인 함황화합물 특유의 마늘향과 파향을 나타내는 휘발성 화합물로 발효 후 함량이 크게 감소하여 무 발효물의 발효 전후 향미특성에 크게 영향을 줄 것으로 생각된다. 반면 acetic acid는 발효 전 0 ng/g에서 발효 후 441.0 ng/g으로 크게 증가하였고, 알코올은 41.1 ng/g에서 334.9 ng/g으로 발효 기간이 경과함에 따라 크게 증가하는 것을 확인할 수 있었다. 발효 2일차에 증가된 acetic acid (441.0 ng/g)와 1-hexanol (139.3 ng/g)은 각각 톡 쏘는 신향, 과일향과 알코올향을 나타내 발효 전후 무 발효물의 향미특성에 영향을 미칠 것으로 생각된다.

• 한국대기환경학회지
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• 제23권1호
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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.