• Proceedings of the KSME Conference
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• 2008.11b
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• pp.2898-2903
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• 2008

The coal considerably is the energy resource which is important with the new remarking energy resource. The coal conversion has two processes which are coal devolatilization and char oxidation. Coal devolatilization is important because it describes up to 70% weight loss and has been shown that nitrogen contribute 60 to 80% of the total NOx produced. The chemical percolation devolatilization(CPD) model is used here to describe coal devolatilization. The model was developed to describe coal devolatilization behavior of rapidly heated coal based on characteristics of the chemical structure of the parent coal. This paper describes CPD model in detail and makes an analysis of Shenhua coal(bituminous) which is used calculated 13-C NMR(carbon-nuclear magnetic resonance).

• Bulletin of the Korean Chemical Society
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• v.13 no.1
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• pp.22-26
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• 1992

The solution structures of the vanadium(V) complexes of iminodiacetate analogues, such as iminodiacetate (IDA), methyliminodiacetate (MeIDA), ethyliminodiacetate (EtIDA), benzyliminodiacetate (BzIDA), pyridine-2,6-dicarboxylate (DPA), and 2-hydroxyethyliminodiacetate (HEIDA), have been studied by $^{13}C-$ and $^{51}V$-NMR spectroscopy. Assuming that the complexes have a $cis-VO_2$ core, IDA, MeIDA, EtIDA, and BzIDA act as facial tridentate ligands to form octahedral complexes, whereas DPA coordinates to $VO_2^+$ as a meridional tridentate. And one water molecule fulfills the remaining site to satisfy the coordination number of six. But HEIDA coordinates to $VO_2^+$ through one IDA moiety and one hydroxyl group, acting as a tetradenate.

• Journal of the Korean Wood Science and Technology
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• v.17 no.4
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• pp.44-56
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• 1989

To recover much residual lignin from the black liquor of kraft pulp. the black liquor was extracted and purified with many organic solvents. Many kinds of lignins were isolated from each fraction obtained and the characteristics of these lignins investigated by $^{13}C$-NMR spectroscopy. If M$\ddot{o}$rck's method was compared with Kirk's method. M$\ddot{o}$rck's method was better than Kirk's method because the particular signals of each lignin occur more in the former than m the latter. Especially the $^{13}C$-NMR spectrum of the MCS fraction identifies with those of other researchers. The experiment that the kraft lignin from Pinus densiflora S. et Z. found in Korea was investigated by $^{13}C$-NMR spectroscopy was performed first in Korea.

• Journal of Microbiology and Biotechnology
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• v.24 no.1
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• pp.13-18
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• 2014

Bacillus subtilis JW-1 was isolated from rhizosphere soil as a potential biocontrol agent of bacterial wilt caused by Ralstonia solanacearum. Seed treatment followed by a soil drench application with this strain resulted in >80% reduction in bacterial wilt disease compared with that in the untreated control under greenhouse conditions. The antibacterial compound produced by strain JW-1 was purified by bioactivity-guided fractionation. Based on mass spectroscopy and nuclear magnetic resonance spectral data ($^1H$, $^{13}C$, $^1H-^1H$ correlation spectroscopies, rotating frame nuclear Overhauser effect spectroscopy, and heteronuclear multiple-bond correlation spectroscopy), the structure of this compound was elucidated as a cyclic lipopeptide composed of a heptapeptide (Gln-Leu-Leu-Val-Asp-Leu-Leu) bonded to a ${\beta}$-hydroxy-iso-hexadecanoic acid arranged in a lactone ring system.

• Polymer(Korea)
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• v.37 no.6
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• pp.777-783
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• 2013

We used dipodal type bis[3-(trimethoxysilyl)propyl]amine (BTMA) silane coupling agent to modify silica nanoparticles to introduce secondary amino groups on the silica surface. These grafted N-H groups were reacted with glycidyl methacrylate (GMA) to introduce polymerizable methacrylate groups on the silica surface. After modification reaction, we used several analytical techniques such as Fourier transform infrared spectroscopy (FTIR), elemental analysis (EA) and solid state $^{13}C$ cross-polarization magic angle spinning (CP/MAS) nuclear magnetic resonance spectroscopy (NMR) to analyze the effects of reaction time, reaction temperature and used GMA concentration on the modification degree between N-H groups on the silica surface and epoxide groups of GMA. We found increased introduction of methacrylate groups on the silica surface by ring opening reaction of epoxide groups of GMA with N-H groups on BTMA treated silica with increased reaction time, reaction temperature and used GMA concentration within our experimental conditions.

• Bulletin of the Korean Chemical Society
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• v.32 no.2
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• pp.687-692
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• 2011

$^1H$ and $^{13}C$ NMR spectra of series of (E)-1-aryl-(2- and 3-thienyl)-2-propenones, that are aldol condensation products between 2- and 3-thiophenecarbaldehydes and m- and p-substituted acetophenones, were examined to make complete assignments of the chemical shifts. Long range couplings, $^4J$ and $^5J$, are observed in the $^1H-^1H$ COSY of both 2- and 3-thienyl compounds, which makes the elucidation of the conformation in solution possible. In contrast, the 2-furyl analogue shows the long range coupling phenomena, but the 3-furyl and phenyl analogues do not show similar phenomena.

• Korean Journal of Pharmacognosy
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• v.9 no.1
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• pp.1-9
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• 1978

The principle of Fourier Transform Nuclear Magnetic Resonance and its usefulness in the fields of pharmacy and biological sciences are described. 1. The $^1H\;and\;^{13}C$ NMR spectra of triostin A and its mixture with purine derivatives were taken. From the analysis of the spectra it has established that triostin A, which exists in two symmetric conformers in chloroform solution, forms complexes only with purine derivatives by the participation of one of the conformers. 2. Also, the $^{13}C$ NMR spectra of "intact" substances in the field of pharmacognosy were taken. From the spectra it was suggested that the method is very useful for natural product research in cooperation with the chemical method.

• Bulletin of the Korean Chemical Society
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• v.14 no.5
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• pp.557-561
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• 1993

The interaction of vanadium(V) with various a-hydroxycarboxylate ligands in aqueous solution at pH 3.2 have been studied by $^{51}V$ and $^{13}C$ NMR spectroscopies. From the results it is supposed that vanadates mainly form the octahedral complexes with lactate, 2-hydroxybutyrate, glycerate, and malate. While, vanadates form the trigonal-bipyramidal complexes with glycolate, tartarate, and 2-hydroxy-3-methylbutyrate, and tetrahedral complexes with pyruvate(diol), 2-hydroxyisobutyrate, and 2-hydroxy-3-methylbutyrate. The bipyramidal products are formed as monomeric compounds. The octahedral products are formed as dimeric compounds with no evidence for a significant proportion of the monomeric derivatives. The complexes are mainly formed through the coordination at the carboxylate and the 2-hydroxyl groups of the ligands.

• Journal of the Korean Wood Science and Technology
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• v.36 no.2
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• pp.63-72
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• 2008

As a part of abating formaldehyde emission of urea-formaldehyde (UF) resin adhesive, this study was conducted to investigate chemical structures of UF resin adhesives with different formaldehyde/urea (F/U) mole ratios, using carbon-13 nuclear magnetic resonance ($^{13}C$-NMR) spectroscopy. UF resin adhesives were synthesized at four different F/U mole ratios such as 1.6, 1.4, 1.2, and 1.0 for the analysis. The analysis $^{13}C$-NMR spectroscopy showed that UF resin adhesives with higher F/U mole ratios (i.e., 1.6 and 1.4) had two distinctive peaks, indicating the presence of dimethylene ether linkages and methylene glycols, a dissolved form of free formaldehyde. But, these peaks were not detected at the UF resins with lower F/U mole ratios (i.e., 1.2 and 1.0). These chemical structures present at the UF resins with higher F/U mole ratios indicated that UF resin adhesive with higher F/U mole ratio had a greater contribution to the formaldehyde emission than that of lower F/U mole ratio. Uronic species were detected for all UF resins regardless of F/U mole ratios.

• Journal of Ginseng Research
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• v.34 no.2
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• pp.113-121
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• 2010

The fresh ginseng roots were extracted with aqueous methanol, and the obtained extracts were partitioned using ethyl acetate, n-butanol, and water, successively. The repeated silica gel and octadecyl silica gel column chromatogaraphy for n-butanol fraction afforded four diol ginseng saponins, ginsenosides $Rb_1$, $Rb_2$, $R_c$, and Rd. The physicochemical, spectroscopic, and chromatographic characteristics of these ginsenosides were measured and compared with those reported in the literature. Some of the peak assignments in previously published $^1H$- and $^{13}C$-nuclear magnetic resonance (NMR) spectra were inaccurate. This study employed two-dimensional NMR experiments, including $^1H-^1H$ correlation spectroscopy, heteronuclear single quantum correlation, and heteronuclear multiple bond connectivity, to determine exact peak assignments.