• Journal of Microbiology and Biotechnology
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• v.9 no.1
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• pp.1-8
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• 1999

Most carbohydrates exist in nature in an insoluble state, which reduces their susceptibility towards various carbohydrases. Accordingly, they require intensive pretreatment for structural modification to enhance an enzyme reaction. The direct conversion of insoluble carbohydrates has distinct advantages for special types of reaction, especially exo-type carbohydrase; however, its application is limited due to structural constraints. This paper introduces two novel heterogeneous enzyme reaction systems for direct conversion of insoluble carbohydrates; one is an attrition coupled enzyme reaction system containing attrition-milling media for enhancing the enzyme reaction, and the other is a heterogeneous enzyme reaction system using extruded starch as an insoluble substrate. The direct conversion of typically insoluble carbohydrates, including cellulose, starch, and chitin with their corresponding carbohydrases, including cellulase, amylase, chitinase, and cyclodextrin glucanotransferase, was carried out using two proposed enzyme reaction systems. The conceptual features of the systems, their reaction characteristics and mechanism, and the industrial applications of the various carbohydrates are analyzed in this review.

• Journal of the Korean Academy of Clinical Electrophysiology
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• v.11 no.1
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• pp.31-38
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• 2013

Purpose : This study was to identify the effect of cognitive reaction following inactive electrode placement when applying anodal transcranial direct current stimulation over the primary motor cortex. Methods : For this study a total of 28 stroke patients participated. Before applying transcranial direct current stimulation, cognitive reaction was measured (P300 of event related potential, cognitive reaction time), and subjects were randomly assigned to two group. Transcranial direct current stimulation was applied to the scalp with an intensity of $0.04mA/cm^2$ for 15 minutes. All subjects were given an anode transcranial direct current stimulation over the primary motor area and inactive electrodes over the deltoid muscle (group I) and supra-orbital area (group II). Cognitive reactions were measured after applying transcranial direct current stimulation. Results : For this study a total of 28 stroke patients participated. Before applying transcranial direct current stimulation, cognitive reaction was measured (P300 of event related potential, cognitive reaction time), and subjects were randomly assigned to two group. Transcranial direct current stimulation was applied to the scalp with an intensity of $0.04mA/cm^2$ for 15 minutes. All subjects were given an anode transcranial direct current stimulation over the primary motor area and inactive electrodes over the deltoid muscle (group I) and supra-orbital area (group II). Cognitive reactions were measured after applying transcranial direct current stimulation. Conclusion : Thus transcranial direct current stimulation on the primary motor area may help cognitive reaction regardless of inactive electrode placement.

• Journal of Ceramic Processing Research
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• v.19 no.6
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• pp.514-518
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• 2018

The direct carbon fuel cell (DCFC) has attracted researcher's attention recently, due to its high conversion efficiency and its abundant fuel, carbon. A DCFC mathematical model has developed in two-dimensional, lab-scale, and considers Boudouard reaction and carbon monoxide (CO) oxidation. The model simulates the CO production by Boudouard reaction and additional electron production by CO oxidation. The Boudouard equilibrium strongly depends on operating temperature and affects the amount of produced CO and consequentially affects the overall fuel cell performance. Two different operating temperatures (973 K, 1023 K) has been calculated to discover the CO production by Boudouard reaction and overall fuel cell performance. Moreover, anode thickness of the cell has been considered to find out the influence of the Boudouard reaction zone in fuel cell performance. It was found that in high temperature operating DCFC modeling, the Boudouard reaction cannot be neglected and has a vital role in the overall fuel cell performance.

• Bulletin of the Korean Chemical Society
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• v.1 no.1
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• pp.23-26
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• 1980

Direct photoisomerizations of benzalpyrrolinones yield the corresponding E-isomers via a singlet state, since no effect of oxygen on the reaction rates was observed. The Z-oxodipyrromethene was photoisomerized to the E-isomer in a degassed system. In an aerobic system the oxodipyrromethene 3 was photoisomerized at the early stage of the reaction and photooxygenated slowly at latter stage of the reaction. For bilirubin, other (possibly Z ${\to}$ E) than self-sensitizing $^1O_2$ reaction should have occurred because of the lack of a solvent effect on the self-sensitized photooxidation reaction rate at the early stage.

• Korean Chemical Engineering Research
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• v.56 no.2
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• pp.291-296
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• 2018

Direct synthesis of methylchlorosilanes was developed by Rochow with addition of copper on the silicon surface as a catalyst and many research were followed. Most of research were focused on the increase of reaction activity through addition of promoters and concentrated on the increase of selectivity of DMDC. However, there are very few studies about the reaction mechanism. Although formation of DMDC was explained in literature, formation of other silanes were not mentioned at all. This reseach focused on the explanation about formation of all silanes obtained during direct reaction and TPD. Reaction paths were proposed by means of dissociative adsorption of methyl chloride and spillover of surface Cl and H. Surface silicon sites were considered as $=SlCl_2$ and $=Sl(CH_3)Cl$. The synthesis of all methylchlorosilanes were explained by the adsorption of methyl group on the silicon sites and by the surface diffusion of nearby Cl and H. The proposed reaction mechanism explains the formation of all silanes during the reaction and also during the TPD process.

• Bulletin of the Korean Chemical Society
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• v.7 no.4
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• pp.314-316
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• 1986

Methods for the preparation of p-nitrocalix[4]-arene via the direct substitution reaction of the p-tert-butylcalix[4]arene which is readily available with high yield from the base-induced direct condensation reaction procedure are described.

• Archives of Plastic Surgery
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• v.32 no.3
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• pp.293-298
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• 2005

Osseointegrated prosthetic auricular reconstruction can be classified as either direct or indirect. In the $Br{\aa}nemark $ system of direct osseointegration, implants are placed into the mastoid process of the temporal bone. In the Epitec system of indirect osseointegration, implants are inserted into a three-dimensional carrier plate that is fixed to the mastoid by means of screws. We experienced forty-four cases using the indirect system and seventeen cases using the direct system. We compared with two systems by complications, such as skin reaction, implant loosening, implant loss. There were no specific differences in the skin reaction around the implants and abutments in relation to age or system used. The degree of skin reaction was different according to the conditions around the implant: in cases of virgin microtia, a skin flap was used to cover the implant, in contrast to grafted skin coverage for failed autogenous reconstruction. In both systems, the skin reaction was more severe and frequent in skin flap than in grafted skin. Loosening of the implant was more frequent in the direct system; however, accidental detachment of the implant from the abutment was more frequent in the indirect system. To reduce complications of skin reaction in osseointegrated prosthetic auricular reconstruction, it is important for soft tissue around implant to immobilize. Therefore, grafted skin is better than skin flap as soft tissue around implant. And immobilization of soft tissue around implant by wound dressing is major facter.

• Journal of environmental and Sanitary engineering
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• v.18 no.4
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• pp.45-51
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• 2003

This study was conducted to remove the color in dyeing wastewater by ozone oxidation process, and the results were summarized as follows ; The 18.3％ of BOD and 56.3％ TOC were removed as decreasing with pH 1 in dyeing wastewater, containing the polyester reducing process. It showed that terephthalic acid was precipitated at low pH. The color of dyeing wastewater was removed by the first order reaction, and the reaction rate constants at pH 3, 7, 12 were investigated $0.234{\;}min^{-1},{\;}0.215{\;}min^{-1}{\;}and{\;}0.201{\;}min^{-1}$ respectively. It showed that color was more effectively removed with direct reaction of ozone than radical reaction(non-direct reaction). As increasing of the water temperature, the reaction rate constants were increased slightly. It indicated that activity of ozone was improved at high water temperature.

• 한국가스학회:학술대회논문집
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• 2005.10a
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• pp.83-87
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• 2005

The kinetics of the direct synthesis of DME was studied under different conditions over a temperature range of $220\~280^{\circ}C$, syngas ratio $1.2\~ 3.0$ All experiment were carried out over hybrid catalyst, composed to a methanol synthesis catalyst (Cu/ZnO/$Al_2O_3$) and a dehydration Catalyst ($\gamma$-Al_2O_3$) The observed reaction rate qualitatively follows a Langmiur-Hinshellwood type of reaction mechanism. Such a mechanism is considered with three reaction, methanol synthesis, methanol dehydration and water gas shift reaction. From a surface reaction with dissociative adsorption of hydrogen, methanol and water, individual reaction rate was determined

• Bulletin of the Korean Chemical Society
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• v.28 no.10
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• pp.1661-1664
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• 2007

Direct reaction of elemental silicon with a gaseous mixture of isopropyl chloride (1) and hydrogen chloride in the presence of copper catalyst using a stirred bed reactor equipped with a spiral band agitator gave isopropyldichlorosilane having a Si-H bond (2a) as a major product and isopropyltrichlorosilane (2b) along with chlorosilanes, trichlorosilane and tetrachlorosilane. A process for production of 2a was maximized using the 1:0.5 mole ratio of 1 to HCl and smaller size of elemental silicon at a reaction temperature of 220 °C. When a reaction was carried out by feeding a gaseous mixture of 1 [12.9 g/h (0.164 mol/h)] and HCl [2.98 g/h (0.082 mol/h)] to a contact mixture of elemental silicon (360 g) and copper (40 g) under the optimum condition for 45 h, 2a among volatile products kept up about 82 mol % until 35 h and then slowly decreased down 68 mol % in 45 h reaction. Finally 2a was obtained in 38% isolated yield (based on 1 used) with an 85% consumption of elemental silicon in a 45 h reaction. In addition to 2a, 2b was obtained as minor product along with chlorosilanes, trichlorosilane, and tetrachlorosilane. The decomposition of 1 was suppressed and the production of 2a improved by adding HCl to 1.