• 대한화학회지
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• 제32권6호
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• pp.588-592
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• 1988

키랄 보조제가 붙어있는 3-acyl-4(S)-isopropyl-1,3-thiazolidine-2-thione[4(S)-AITT]을 라세미 아민과 가아민 분해반응을 시켰을때 광학활성을 갖는 아미드(S-excess)와 아민(R-excess)이 얻어지는 입체 선택적인 반응이 관찰되었다. 이와같은 입체 선택적인 반응은 macrocyclic diamide, macrocylic sperimidine alkaloid, peptide 합성에 이용될 수 있다. 가아민 분해반응의 속도는 아민의 입체적인 영향을 많이 받았고 반응이 종료점은 노락색의 소실로 쉽게 관찰되었다. 4(S)-AITT는 4(S)-isopropyl-1,3-thiazolidine-2-thione과 carboxylic acid로부터 얻었다.

• Journal of Applied Biological Chemistry
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• 제51권6호
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• pp.307-314
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• 2008

To explore the optimal conditions for the removal of $H_{2}S$ gas by biofiltration, various conditions, including inlet $H_{2}S$ concentration, flow rate, moisture, and cell number, were examined. Heterotrophic bacteria were isolated from the compost of the animal excreta. A strain that effectively removed $H_{2}S$ was selected and identified as Rhodococcus rhodochrous B261 by analysis of its 16S rDNA sequence. A cell number of $10^{7}\;cfu/g^{-}compost$ was sufficient to dominate the microbiota, and an effective removal was observed at $H_{2}S$ gas concentrations below 220 mg/L. The moisture content of 33-38% was suitable for activation of the microbial activity and delaying the desiccation. Higher flow rates resulted in lower removal rates of the $H_{2}S$ gas. Under the conditions of $10^7\;cfu/g^{-}compost$, $H_{2}S$ gas concentrations of 220 mg/L, and moisture content of 33-38%, the inlet $H_{2}S$ gas concentrations of 120 and 400 mg/L were completely removed for 34 and 12 days, respectively. The amount of sulfur removed was $2.99{\times}10^{-9}H_{2}S-S/cell$, which was suggested as the amount of sulfur removed by a single cell. The biofilter consisting of the compost and R. rhodochrous B261 could be suitable for a long-term biofilteration for the removal of $H_{2}S$ and other malodorous compounds.

• 대한금속재료학회지
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• 제56권12호
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• pp.900-909
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• 2018

A $ZnO/TiO_2$ photocatalyst decorated with PbS quantum dots (QDs) was synthesized to achieve high photocatalytic efficiency for the decomposition of dye in aqueous media. A $TiO_2$ porous layer, as a precursor photocatalyst, was fabricated using micro-arc oxidation, and exhibited irregular porous cells with anatase and rutile crystalline structures. Then, a ZnO-deposited $TiO_2$ catalyst was fabricated using a zinc acetate solution, and PbS QDs were uniformly deposited on the surface of the $ZnO/TiO_2$ photocatalyst using the successive ionic layer adsorption and reaction (SILAR) technique. For the PbS $QDs/ZnO/TiO_2$ photocatalyst, ZnO and PbS nanoparticles are uniformly precipitated on the $TiO_2$ surface. However, the diameters of the PbS particles were very fine, and their shape and distribution were relatively more homogeneous compared to the ZnO particles on the $TiO_2$ surface. The PbS QDs on the $TiO_2$ surface can induce changes in band gap energy due to the quantum confinement effect. The effective band gap of the PbS QDs was calculated to be 1.43 eV. To evaluate their photocatalytic properties, Aniline blue decomposition tests were performed. The presence of ZnO and PbS nanoparticles on the $TiO_2$ catalysts enhanced photoactivity by improving the absorption of visible light. The PbS $QDs/ZnO/TiO_2$ heterojunction photocatalyst showed a higher Aniline blue decomposition rate and photocatalytic activity, due to the quantum size effect of the PbS nanoparticles, and the more efficient transport of charge carriers.

• Journal of Ginseng Research
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• 제24권1호
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• pp.35-40
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• 2000

홍삼에서 분리한 수용성 갈변물질의 항산화 활성을 linoleic acid, Ox-brain autoxidant, Fe$^{2+}$ ADP/NAD 및 cumene hydoperoxide 시스템에서 조사한 결과를 다음과 같다. 1. Linoleic acid :투석내액의 갈변물질보다 투석외액의 갈변물질 쪽에서 hydroperoxy radical 저해율이 높은 것으로 나타났으며, 이때 S-2의 산화저해율은 S-1, L시험구보다 적은 농도에서 저해율이 높았다. S-2의 산화저해율은 49,52, 62.44 및 97.5%로 나타나 첨가농도가 증가함에 따라 linoleic acid 산화저해율은 높았다. 2. Ox-brain autoxidant : 자동산화에의한 항산화활성을 조사한 결과, 투석내액의 갈변물질보다 투석외액의 갈변물질 쪽에서 자동산화에 의한 항산화활성이 높은 것으로 나타났다. 특히S-2의 항산화 활성은 22.5, 31.7, 31.9 및 33.5%로 나타났다. 3. Fe$^{2+}$ ADP/NAD 및 cumene hydroperoxide : 횐쥐 간의 microsome 분획을 분리하여 수용성 갈변물질의 ADP/NABP 및 cumene hydroperoxide 항산화 활성을 조사한 결과, 모든 시험구에서 반응 초기에 항산화 활성이 있으나, 반응 시간이 길수록 항산화 활성은 감소하였다. 그 활성의 순서는 S-2>S-1>L순으로 나타났으나 항산화 활성의 강도는 전체적으로 약하게 나타났다.

• Genes and Genomics
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• 제40권12호
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• pp.1287-1300
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• 2018

Hydrogen sulfide ($H_2S$), a small bioactive gas, has been proved functioning in plant growth and development as well as alleviation of abiotic stresses, which including promoting seed germination, accelerating embryonic root growth, regulating flower senescence, inducing stomatal closure, and defending drought, heat, heavy metals and osmotic stresses etc. However, the molecular functioning mechanism of $H_2S$ was still unclear. The primary objective of this research was to analyze the transcriptional differences and functional genes involved in the $H_2S$ responses. In details, 4-week-old plantlets in tissue culture of grapevine (Vitis vinifera L.) cultivar 'Zuoyouhong' were sprayed with 0.1 mM NaHS for 12 h, and then transcriptome sequencing and qRT-PCR analysis were used to study the transcriptional differences and functional genes involved in the $H_2S$ responses. Our results indicated that 650 genes were differentially expressed after $H_2S$ treatment, in which 224 genes were up-regulated and 426 genes were down-regulated. The GO enrichment analysis and KEGG enrichment analysis results indicated that the up-regulated genes after $H_2S$ treatment focused on carbon metabolism, biosynthesis of amino acids, and glycolysis/gluconeogenesis, and the down-regulated genes were mainly in metabolic pathways, biosynthesis of secondary metabolites, and plant hormone signal transduction. Analyzing the transcription factor coding genes in details, it was indicated that 10 AP2/EREBPs, 5 NACs, 3 WRKYs, 3 MYBs, and 2 bHLHs etc. transcription factor coding genes were up-regulated, while 4 MYBs, 3 OFPs, 3 bHLHs, 2 AP2/EREBPs, 2 HBs etc. transcription factor coding genes were down-regulated. Taken together, $H_2S$ increased the productions in secondary metabolites and a variety of defensive compounds to improve plant development and abiotic resistance, and extend fruits postharvest shelf life by regulating the expression of AP2/EREBPs, WRKYs, MYBs, CABs, GRIP22, FERRITINs, TPSs, UGTs, and GHs etc.

• 대한소아치과학회지
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• 제32권2호
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• pp.207-216
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• 2005

Mutans streptococci는 치아우식증과 관련이 있다고 보고되고 있으며, 이 streptococci 종 중에서 S. mutans나 S. sobrinus가 인간의 치아우식증에서 가장 일반적으로 나타난다. 치아우식증에서 이 세균종의 분포는 인종과 지역에 따라 다양하다. 본 연구에서는 2-6세인 52명의 치아우식증 환자에서 비우식부위와 우식부위로부터 치태를 채취하여 DNA를 추출한 후 dex와 gtf 유전자에 기초한 S. mutans와 S. sobrinus에 특이한 primer를 제작한 후 PCR을 시행하여 S. mutans와 S. sobrinus의 분포도를 조사하여 다음과 같은 결과를 얻었다. 1. 어린이 치아우식증 환자에서 S. mutans나 S. sobrinus가 발견된 어린이는 37명(71.2%)이었다. 2. 이들 어린이 중에서, S. mutans 또는 S. sobrinus가 비우식부위에서만 발견된 어린이는 3명(5.8%), 우식부위에서만 발견된 어린이는 22명(42.3%), 두 부위 모두에서 발견된 어린이는 12명(23.1%)이었다. 3. S. mutans나 S. sobrinus가 나타난 비우식부위 치태는 15개(28.8%), 우식부위치태는 34개(65.4%)였다. 4. 비우식부위의 경우 S. mutans만 출현한 어린이는 52명 중 8명(15.4%), S. sobrinus만 출현한 어린이는 6명(11.5%), 두 세균종이 같이 출현한 어린이는 1명(1.9%)이었다. 5. 우식부위에서 S. mutans만 출현한 어린이는 52명 중 24명(46.2%), S. sobrinus만 출현한 어린이는 2명(3.8%), 두 세균종이 같이 출현한 어린이는 8명(15.4%)이었다. 6. S. mutans는 gtf에 기초한 primer, S. sobrinus는 dex에 기초한 primer가 PCR에서 효과적으로 각각의 세균을 검출하였다. 이상의 결과로 미루어 우리나라 어린이의 경우 치아우식증은 MS와 밀접한 연관성이 있으며, MS중에서도 S. mutans가 중요하다고 판단된다. 한편 S. mutans와 S. sobrinus의 동반출현은 치아우식증과 더욱 밀접한 관련이 있는 것으로 보인다.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2003년도 International Meeting on Information Display
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• pp.203-206
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• 2003

$Y_2O_2S:Eu$ phosphors with fine particle have been synthesized by citric acid-gel method. In this method, $Na_2S_2O_3$ was added to $Y_2O_3S:Eu$ precursor, then the mixture was fired at $1000^{\circ}C$ for 3h in $S_2$ atmosphere. When the $Y_2O_3S:Eu$ precursor was pre-annealed at $400{\sim}700^{\circ}C$ before the firing of the mixture, the fine particles with a diameter of around 1 ${\mu}m$ were obtained after the firing. The phosphor pre-annealed at $400^{\circ}C$ showed a luminance and CIE color coordinates of 2350 $cd/m^2$ and (0.61, 0.37), respectively, at under excitation of 3 kV and $60{\mu}A/cm^2$.

• 대한수학회보
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• 제40권1호
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• pp.29-51
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• 2003

In this paper we construct a natural filtration associated to the plethysm $S_{r}(\wedge^2 \varphi)$ over arbitrary commutative ring R. Let $\phi$ : G longrightarrow F be a morphism of finite free R-modules. We construct the natural filtration of $S_{r}(\wedge^2 \varphi)$ as a $GL(F){\times}GL(G)$- complex such that its associated graded complex is ${\Sigma}_{{\lambda}{\in}{\Omega}_{\gamma}}=L_{2{\lambda}{\varphi}$, where ${{\Omega}_{\gamma}}^{-}$ is a set of partitions such that $│\wedge│\;=;{\gamma}\;and\;2{\wedge}$ is a partition of which i-th term is $2{\wedge}_{i}$. Specializing our result, we obtain the filtrations of $S_{r}(\wedge^2 F)\;and\;D_{r}(D_2G).

• Applied Science and Convergence Technology
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• 제26권3호
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• pp.47-49
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• 2017

Photocurrent enhancement has been investigated in monolayer (1L) $MoS_2$ with PbS quantum dots (QDs). A metal-semiconductor-metal (Au-1L $MoS_2$-Au) junction device is fabricated using a standard photolithography method. Considerably improved photo-electrical properties are obtained by coating PbS QDs on the Au-1L $MoS_2$-Au device. Time dependent photoconductivity and current-voltage characteristics are investigated. For the QDs-coated $MoS_2$ device, it is observed that the photocurrent is considerably enhanced and the decay life time becomes longer. We propose that carriers in QDs are excited and transferred to the $MoS_2$ channel under light illumination, improving the photocurrent of the 1L $MoS_2$ channel. Our experimental findings suggest that two-dimensional layered semiconductor materials combined with QDs could be used as building blocks for highly-sensitive optoelectronic detectors including radiation sensors.

• 한국농공학회논문집
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• 제59권6호
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• pp.101-108
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• 2017

This study attempted to improve the accuracy of streamflow and baseflow prediction of Soil and Water Assessment Tool (SWAT) by applying baselfow recession constants for each sub-watershed. This study set two different scenarios (S1 and S2) to evaluate the impact of application of baseflow recession constants for each sub-watershed on streamflow prediction. In S1, Only the baseflow recession constant obtained from the streamflow station located in the final outlet of study area was applied for whole sub-watersheds. In S2, baseflow recession constants obtained from six different streamflow stations were applied for each sub-watershed. Then, baseflow was separated form the measured streamflow data and the predicted streamflow of S1 and S2 using Web-based Hydrograph Analysis Tool (WHAT). The results showed Nash-Sutcliff efficiency (NSE) and $R^2$ of S2 were a little higher than these of S1 in both streamflow and baseflow prediction results. However, it is important that S2 reflected physical meaning of baseflow recess. Also, recession part of hydrograph in S2 was calibrated better than that of S1 compared to the measured hydrograph.