• Korean Chemical Engineering Research
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• v.61 no.2
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• pp.226-233
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• 2023

To create an environmentally sustainable fuel with a low sulfur concentration, requires alternative sulfur removal methods. During the course of this study, a high surface gamma alumina-supported ZnO nanocatalyst with a ZnO/-Al₂O₃ ratio of 12% was developed and tested for its ability to improve the activity of the oxidative desulfurization (ODS) process for the desulfurization of kerosene fuel. Scanning electron microscopy (SEM) and Brunauer-Emmett-Teller (BET) were used to characterize the produced nanocatalyst. In a digital batch baffled reactor (20~80 min), the effectiveness of the synthesized nanocatalyst was tested at different initial concentrations of dibenzothiophene (DBT) of 300~600 ppm, oxidation temperatures (25~70 ℃), and oxidation periods (0.5, 1, and 2 hours). The baffles included in the digital baffled batch reactor resist the swirling of the reaction mixture, thus facilitating mixing. The ODS procedure yielded the maximum DBT conversion (95.5%) at 70 ℃ with an 80-minute reaction time and an initial DBT level of 600 ppm. The most precise values of kinetic variables were subsequently determined using a mathematical modelling procedure for the ODS procedure. The average absolute error of the simulation findings was less than 5%, demonstrating a good degree of agreement with the experimental results acquired from all runs. The optimization of the operating conditions revealed that 99.1% of the DBT can be removed in 140 minutes.

• Progress in Medical Physics
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• v.25 no.4
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• pp.271-280
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• 2014

Recently, digital breast tomosynthesis (DBT) has been investigated to overcome the limitation of conventional mammography for overlapping anatomical structures and high patient dose with cone-beam computed tomography (CBCT). However incomplete sampling due to limited angle leads to interference on the neighboring slices. Many studies have investigated to reduce artifacts such as interference. Moreover, appropriate filters for tomosynthesis have been researched to solve artifacts resulted from incomplete sampling. The primary purpose of this study is finding appropriate filter scheme with FBP reconstruction for DBT system to reduce artifacts. In this study, we investigated characteristics of various filter schemes with simulation and prototype digital breast tomosynthesis under same acquisition parameters and conditions. We evaluated artifacts and noise with profiles and COV (coefficinet of variation) to study characteristic of filter. As a result, the noise with parameter 0.25 of Spectral filter reduced by 10% in comparison to that with only Ramp-lak filter. Because unbalance of information reduced with decreasing B of Slice thickness filter, artifacts caused by incomplete sampling reduced. In conclusion, we confirmed basic characteristics of filter operations and improvement of image quality by appropriate filter scheme. The results of this study can be utilized as base in research and development of DBT system by providing information that is about noise and artifacts depend on various filter schemes.

• Bulletin of the Korean Chemical Society
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• v.34 no.6
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• pp.1814-1822
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• 2013

By using density functional theory calculations, we have performed a systemic study on the electronic structures and topological properties of interactions between N-butylpyridinium nitrate ($[BPY]^+[NO_3]^-$) and thiophene (TS), benzothiophene (BT), dibenzothiophene (DBT), naphthalene (NAP). The most stable structure of $[BPY]^+[NO_3]^-$ ion pair indicates that hydrogen bonding interactions between oxygen atoms on $[NO_3]^-$ anion and C2-H2 on pyridinium ring play a dominating role in the formation of ion pair. The occurrence of hydrogen bonding, ${\pi}{\cdots}$H-C, and ${\pi}{\cdots}{\pi}$ interactions between $[BPY]^+[NO_3]^-$ and TS, BT, DBT, NAP has been corroborated at the molecular level. But hydrogen bonding and ${\pi}{\cdots}{\pi}$ interactions between $[BPY]^+[NO_3]^-$ and NAP are weak in terms of structural properties and NBO, AIM analyses. DBT is prior to adsorption on N-butylpyridinium nitrate ionic liquid.

• KSBB Journal
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• v.17 no.3
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• pp.295-301
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• 2002

The effects of nonionic surfactant (SPAN 20) on the desulfurization process by Rhodococcus sp. strain IGTS8 have been investigated at various oil/water ratios, pHs and concentrations of surfactant. The hexadecane containing DBT was employed as model oil. The presence of surfactant in the oil/water mixture stabilized the oil/water interface, thus enhanced the efficiency of desulfurization. The volume percentages of oil in the oil/water mixture were 30, 50 and 70%. The concentrations of surfactant were varied from 0 to 0.33 wt% relative to water phase. In general, the biodesulfurization efficiencies were decreased as the concentration of SPAN 20 and the volume percentage of oil phase increased.

• 한국생물공학회:학술대회논문집
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• 2000.11a
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• pp.540-543
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• 2000

Microbial desulfurization using a biocatalyst which is capable of selectively liberating sulfur from HDS-refractory organic sulfur compounds is an alternative biotechnology to the current technology of hydrodesulfurization. The system used in the experiments is a two phase system consisting of 0.1%(w/v) dibenzothiophene in hexadecane as model oil and a mineral medium for cell growth. Rhodococcus rhodochrous IGTS8, a desulfurization strain, was grown in flask culture at different oil phase ratio with 10% and 30%. Most of the dibenzothiophene was converted to 2-hydroxybiphenyl when the oil ratio was 10%, but wasn't when the oil ratio was 30%. However, the total degraded DBT amounts were similar. In experiments of adjusting pH to improve the efficiency of degradation, the amounts of degraded DBT were increased by 50%. When the modified medium which has two-fold nutrients than those of minimal salt medium was used, the amounts of degraded DBT were increased by 32%. When both of the methods were used, the efficiency was increased by 136%.

• The Journal of Dong Guk Oriental Medicine
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• v.3
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• pp.91-106
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• 1994

This Study was performed to prove the effects of Gungsindodamtang (GDT) and Dangquibohyultang (DBT) on the cosntents of Serotonin and Catecholamine in the Brain and the Plasma of the Reserpine treated rats. High-Perfomance Liquid Chromatography was used for measuring the contents of the Serotonin and Catecholamine. The results were as follows. 1. norepinephrine contents in the Brain were increased significantly in GDT-treated group and DBT-treated group in comparison with the control group. 2. epinephrine and serotonin contents in the Brain were increased in all the sample groups but have not significance. 3. norepinephrine contents in the plasma were increased significantly in all the sample groups in comparison with the control group. 4. epinephrine contents in the plasma were increased in all the sample groups but have not significance. 5. serotonin contents in the plasma were increased significantly in DBT-treated group in comparison with the control group, and inreased in GDT-treated group but have not significance. According to the above results, it is considered that Dangquibohyultang could be applied more effectively than Gungsindodamtang in decrease of the serotonin and catecholamine and other symptoms induced by Reserpine.

• Journal of Microbiology and Biotechnology
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• v.13 no.4
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• pp.578-583
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• 2003

The desulfurization genes (dszABC) were cloned from Gordonia nitida. Nucleotide sequences similarity between the dszABC genes of G. nitida and those of Rhodococcus rhodochrous IGTS8 was 89%. The similarities of deduced amino acids between the two were 86% for DszA, 86% for DszB, and 90% for DszC. The G. nitida dszABC genes were expressed in several different Escherichia coli strains under an inducible trc promoter. Cultivation of these metabolically engineered E. coli strains in the presence of 0.2 mM dibenzothiophene (DBT) allowed the conversion of DBT to 2-hydroxybiphenyl (2-HBP), which is the final metabolite of the sulfur-specific desulfurization pathway. The maximum conversion of DBT to 2-HBP was 16% in 60 h. Recombinant E. coli was applied for the deep desulfurization of diesel oil supplemented into the medium at 5% (v/v). Sulfur content in diesel oil was decreased from 250 mg sulfur/1 to 212.5 mg sulfur/1, resulting in the removal of 15% of sulfur in diesel oil in 60 h.

• Korean journal of applied entomology
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• v.12 no.2
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• pp.63-70
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• 1973

Weed control tests with 6 herbicides which seem to have selectivity of absorption by roots of rice were carried out by the rate of application, the depth of incorporation and the time of application in comparison with the after transplanting treatment of MO in SiCL soil. Soil-incorporated treatment of Ronstar, Saturn, TOK and Saturn·5 were applied before transplanting and soil surface treatment of Machete, PCP and MON·0385 were applied. The results are summarized as follows: 1. Initial crop injury and growth Soil surface treatment before transplanting of PCP of 1,000g ai/10a caused heavy initial injury, which was recovered from by about 50 days after application. Saturn-S at 4kg prod.110a caused slight crop injury sectionally, which was soon recovered from. And little crop injury was caused by other treatments. 2. Effect in weed control Excellent weed control of 90 to 97.7 percent was obtained, when measured 27 days after transplanting, by all the treatments. More than 90 percent weed control was maintained for about 73 days after transplanting by all the treatments of Ronstar and Saturn-S of 3 to 4kg prod./10a. The treatments of MON-0385 of 175g ai/10a and TOK of 280g ai/10a showed somewhat poor weed control. 3. Yield No reduction of yield was observed at all the plots except the non·weeded plot at which 11.4 percent yield reduction was observed compared with the hand weeding plot. The yield was increased by the 1 DBT and 2 DBT treatments of Machete of 210g ai/10a, the treatments of Ronstar of 60g ai/10a, when incorporated to the depth of 2.5 and 12cm, the incorporation treatment of Saturn-S of 3kg prod./10a and 1 DBT treatment of MON-0385 of 175g ai/10a.

• Analytical Science and Technology
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• v.22 no.5
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• pp.360-368
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• 2009

Tributyltin (TBT) use has been prohibited by the IMO (International Maritime Organization), as well as Korea, since 2003. This prohibition has affected a gradual reduction in TBT use in maritime environs (seawater, sediment, and biosamples) in several countries. In this study, Crassostrea gigas (oyster) and Tapes philippinarum (manila clam) were chosen and measured for butyltin compound concentrations to verify TBT pollution levels since its 2003 ban. Specimens were taken directly from farms for concentration measurement, where Crassostrea gigas and Tapes philippinarum are cultivated, as well as prevalent locations predicted to have been polluted. Concentrations of MBT, DBT, and TBT of Crassostrea gigas were measured to be N.D -N.D., N.D. -N.D., and N.D. -60.21 ng Sn $g^{-1}$ (wet wt), respectively. Regarding Tapes philippinarum, MBT, DBT, and TBT were N.D. -12.27 ng Sn $g^{-1}$ (wet wt), N.D. -45.95 ng Sn $g^{-1}$ (wet wt), and N.D.-7.30 ng Sn $g^{-1}$ (wet wt), respectively. For this research, a correlative study was conducted to determine butyltin compound concentration in Crassostrea gigas at the locations where measurements were made in 1994 to determine to what extent TBT pollution level decreased. A decrease in all 7 sites was observed. In 4 of the 7 samples, butyltin compounds were measured to be below the detection limit, while that of the Tapes philippinarum did not appear high compared to foreign research data.

• Proceedings of the Zoological Society Korea Conference
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• 1997.10b
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• pp.250.1-250
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• 1997