• Bulletin of the Korean Chemical Society
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• v.12 no.2
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• pp.149-153
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• 1991

Chlorotrimethylsilane reacts with chromic anhydride to form a very reactive neutral chromium (Ⅵ) oxidizing agent. The active oxidizing species is not trimethylsilyl chlorochromate as was previously reported but chromyl chloride generated in equilibrium concentration. This oxidizing agent was proved very suitable for benzylic oxidations of toluenes and alkylbenzenes to benzaldehydes and aralkyl ketones. Dichlorodimethylsilane and trichlormethylsilane also react with chromic anhydride to form chromyl chloride in an equilibrium concentration.

• Bulletin of the Korean Chemical Society
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• v.10 no.2
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• pp.185-190
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• 1989

Geometries for a number of representative ${\beta}$ -lactam antibiotics (penams, cephems and monobactams) have been calculated by computer graphics/molecular mechanics energy minimization procedures using both MM2 and AMBER force fields. The calculated geometries have been found in reasonable agreement with the geometries reported in the X-ray crystal structures, especially in terms of the pyramidal character of the amide nitrogen in the ${\beta}$-lactam ring and the Cohen distance. Based on these calculations, it is suggested that the nitrogen atom in the monobactams may also have pyramidal geometries in the biologically active conformations.

• Bulletin of the Korean Chemical Society
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• v.5 no.6
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• pp.223-226
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• 1984

(Z)-13-Eicosen-10-one (1), one of the active components of the female pheromone of the peach fruit moth, Carposina niponensis Walsingham, was synthesized from 2-nonanone, succinic anhydride, and n-nonyllithium. The key step involves the preparation of 13-eicosyn-10-one from an epoxyketone via Eschenmoser cleavage.

• Bulletin of the Korean Chemical Society
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• v.22 no.3
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• pp.263-266
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• 2001

Isopropylation of phenol with 2-propanol has been carried out over Na-exchanged ZSM-5 zeolites to determine the effect of catalyst acidity on phenol conversion and product selectivity. The acid type and strength of the catalyst such as Lewis, weak and strong Bronsted acid sites are measured by pyridine adsorbed XPS and the catalytic properties are interpreted in terms of the acid properties. The active site and mechanism for the reaction are suggested based on evidence of study from the reactant adsorbed FT-IR.

• Bulletin of the Korean Chemical Society
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• v.11 no.4
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• pp.323-327
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• 1990

The synthesis and some biological properties of $7{\beta} $-[2-(Z)-(2-aminothiazole-4-yl)-2-(N-substitutedcar bonyl)ethoxyiminoacetamido]-3-vinyl-3-cephem-4- carboxylic acid are described. The effect of substituents on the carbamoly group in the 7-side chain were investigated in order to improve antibacterial activities. Two of these new orally active $7{\beta} $-lactam derivatives showed wide expanded antimicrobial activities against Gram-positive and Gram-negative bacteria, including Pseudomonas aeruginosa, as well as good stability to $7{\beta} $ -lactamases.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.4
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• pp.57-62
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• 2018

This study was designed to analyze the chemical composition and antioxidant activity of various vegetable oils (pumpkin seed oil, camellia seed oil, red pepper seed oil and peanut oil) using adsorbents (active carbon, acid clay, kaolin). Their chemical composition was analyzed by GCMS. Their antioxidant activity was evaluated by measuring their DPPH and ABTS radical scavenging activity. After the treatment with the adsorbents, the contents of most of the fatty acids and active ingredients contained in the four kinds of vegetable oils were reduced. After the treatment with the three adsorbents, the linoleic acid and erythrodiol contents of the pumpkin seed oil were reduced. In the case of the camellia seed oil, the fatty acids content was decreased, but there was no loss of vitamin E after the acid clay treatment. The content of the compound capsaicin, which forms part of the spicy component of red pepper seed oil, was reduced by 53.33% after the acid clay treatment. The peanut oil showed the lowest loss of sitosterol compound in the group treated with active carbon. The antioxidant activity was observed to be in the order of pumpkin seed oil (kaolin>acid clay>active carbon), camellia seed oil (acid clay>kaolin>active carbon), red pepper seed oil (kaolin>acid clay>active carbon) and peanut oil (active carbon>acid clay>kaolin).

• Korean Journal of Microbiology
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• v.33 no.4
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• pp.267-273
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• 1997

Various physico-chemical and microbiological parameters of a composting system were compared with respect to their potential use for the monitoring and evaluation of composting processes for cattle manure. The temperature changed within a range of $30-65^{\circ}C$ during the whole composting process, and the period of active composting (>$40^{\circ}C$) persisted for 16 days. The concentrations of total carbon, total nitrogen, and organic matter decreased by 15% during active composting, but significant changes in C/N ratio were not observed. The decrease of temperature in the latter period of active composting caused a decrease of $NH_4^+-N$ and an increase of $NO_3^--N$ in the composting pile. When temperature exceeded $50^{\circ}C$, the population of thermophiles was higher than that of mesophiles by more than 1 or 2 orders of magnitude. Correlation analyses showed that amylase activity correlated positively with the population of mesophiles and reducing sugar content, but negatively with the population of thermophiles. Amylase activity was higher at the beginning of active composting, whereas cellulase, xylanase and ligninase activities which showed close relationship with each other, increased continually during active cornposting, suggesting the distinction of temporal niches between amylose-degrading and lignocellulose-degrading bacteria in the same habitat.

• Bulletin of the Korean Chemical Society
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• v.26 no.4
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• pp.563-568
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• 2005

The Pt/C and Pd/C catalysts were prepared from conventional chloride precursors by adsorption or precipitation-deposition methods. Their activities for hydrogenation reactions of cyclohexene and acetophenone were compared with those of commercial catalysts. The Pt/C and Pd/C catalysts obtained from the adsorption procedure reveal higher hydrogenation activity than commercial catalysts and the catalysts prepared by the precipitation-deposition method. Their improved performances are attributed to the decreased metal crystallite sizes of Pt or Pd formed on the active carbon support upon the adsorption of the precursors probably due to the same negative charges of the chloride precursor and the carbon support. Under the preparation conditions studied, the reduction of the supported catalysts using borohydrides in liquid phase is superior to a gas phase reduction by using hydrogen in the viewpoint of particle size, hydrogenation activity and convenience.

• Journal of the Korean institute of surface engineering
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• v.55 no.6
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• pp.441-447
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• 2022

Silicon-based materials are one of the most promising anode active materials in lithium-ion battery. A carbon layer decorated on the surface of silicon particles efficiently suppresses the large volume expansion of silicon and improves electrical conductivity. Carbon coating through chemical vapor deposition (CVD) is one of the most effective strategies to synthesize carbon- coated silicon materials suitable for mass production. Herein, we synthesized carbon coated SiOx via pilot scale CVD reactor (P-SiO_x@C) and carbon coated SiO_x via industrial scale CVD reactor (I-SiO_x@C) to identify physical characteristic changes according to the CVD capacity. Reduced size silicon domains and local non-uniform carbon coating layer were detected in I-SiO_x@C due to non-uniform temperature distribution in the industrial scale CVD reactor with large capacity, resulting in increased surface area due to severe electrolyte consumption.

• Korean Journal of Pharmacognosy
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• v.15 no.2
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• pp.85-90
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• 1984

The whole plant of Duchesnea indica (Andr.) Focke (Rosaceae) which has been used in folklore in treating amenorrhea, inflammation, fever and traumatic injuries, in detoxifying and breaking up clots, was studied. The pharmacological test showed that the water extract had estrogenic and histaminergic actions, but no antiserotonin action. As a result of systematic separation in order to detect the active compounds revealing the estrogenic effect, the active compounds were found in the ether fraction. TLC of the ether fraction revealed 8 spots. Among them three major spots (Rf=0.54, 037, 0.31) were separated by preparative TLC. Some chemical properties of those major spots suggested that they were phenolic compounds, but that they were neither linoleic acid nor ${\beta}-sitosterol$ previously reported.