• Bulletin of the Korean Chemical Society
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• v.12 no.3
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• pp.265-270
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• 1991

Theoretical calculations on the stabilization energies of framework atoms in hydrolyses Co(Ⅱ )-exchanged zeolite A were made using some potential energy functions and optimization program. The protons which are produced by hydrolysis of $[Co(H_2O)_n]^{2+}$ ion in large cavity showed a tendency to attack the framework oxygen atom O(1) preferentially, and the oxygen atom O(4) within OH- ion was coordinated at Al atom. The weakness of bonds between T(Si, Al) and oxygen by attack of proton and too large coordination number around small aluminum atom will make the framework of Co(Ⅱ)-exchanged zeolite A more unstable. The stabilization energy of $Co_4Na_4$-A framework (- 361.57 kcal/mol) was less than that of thermally stable zeolite A($Na_{12-}$A: - 419.68 kcal/mol) and greater than that of extremely unstable Ba(Ⅱ)-exchanged zeolite A($Ba_{6-}$A: - 324.01 kcal/mol). All the data of powder X-ray diffraction, infrared and Raman spectroscopy of Co(Ⅱ)-exchanged zeolite A showed the evidence of instability of its framework in agreement with the theoretical calculation. Three different groups of water molecules are found in hydrated Co(Ⅱ )-exchanged zeolite A; W(Ⅰ) group of water molecules having only hydrogen-bonds, W(Ⅱ) group water coordinated to $Na^+$ ion, ans W(Ⅲ) group water coordinated to Co(Ⅱ) ion. The averaged interaction energy of each water group shows the decreasing order of W(Ⅲ)>W(Ⅱ)>W(Ⅰ).

• Current Applied Physics
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• v.18 no.12
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• pp.1546-1552
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• 2018

The polymer nanocomposite as a gate dielectric film was prepared via sol-gel method. The formation of crosslinked structure among nanofillers and polymer matrix was proved by Fourier transform infrared spectroscopy (FT-IR). Differential thermal analysis (DTA) results showed significant increase in the thermal stability of the nanocomposite with respect to that of pure polymer. The nanocomposite films deposited on the p- and n-type Si substrates formed very smooth surface with rms roughness of 0.045 and 0.058 nm respectively. Deconvoluted $Si_{2s}$ spectra revealed the domination of the Si-OH hydrogen bonds and Si-O-Si covalence bonds in the structure of the nanocomposite film deposited on the p- and n-type Si semiconductor layers respectively. The fabricated n-channel field-effect-transistor (FET) showed the low threshold voltage and leakage currents because of the stronger connection between the nanocomposite and n-type Si substrate. Whereas, dominated hydroxyl groups in the nanocomposite dielectric film deposited on the p-type Si substrate increased trap states in the interface, led to the drop of FET operation.

• Korean Journal of Breeding Science
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• v.43 no.5
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• pp.479-489
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• 2011

Gluten is the main functional component of wheat, and is the main source of the viscoelastic properties in a dough. One of the gluten group is glutenin, which is composed of high molecular weight (HMW) and low molecular weight (LMW) subunits. The HMW glutenin subunits (HMW-GS) have been shown to play a crucial role in determining the processing properties of the grain. They are encoded by the Glu-1 loci located on the long arms of homeologous group one chromosomes, with each locus comprising two genes encoding x- and y-type subunits. The presence of certain HMW subunits is positively correlated with good bread-making quality. The highly conserved N- and C- terminal contaning cystein residues which form interand intra-chain disulphide bonds. This inter chain disulphide bonds stabilize the glutenin polymers. In contrast, the repetitive domains that comprise the central part of the HMW-GS are responsible for the elastic properties due to extensive arrays of interchain hydrogen bonds. In this review, we discuss HMW-GS, HMW-GS structure and gluten elasticity, relationship between HMW-GS and bread wheat quality and genetic engineering of the HMW-GS.

• Journal of Microbiology and Biotechnology
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• v.32 no.12
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• pp.1561-1572
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• 2022

Plastic pollution has been recognized as a serious environmental problem, and microbial degradation of plastics is a potential, environmentally friendly solution to this. Here, we analyzed and compared microbial communities on waste plastic films (WPFs) buried for long periods at four landfill sites with those in nearby soils to identify microbes with the potential to degrade plastics. Fourier-transform infrared spectroscopy spectra of these WPFs showed that most were polyethylene and had signs of oxidation, such as carbon-carbon double bonds, carbon-oxygen single bonds, or hydrogen-oxygen single bonds, but the presence of carbonyl groups was rare. The species richness and diversity of the bacterial and fungal communities on the films were generally lower than those in nearby soils. Principal coordinate analysis of the bacterial and fungal communities showed that their overall structures were determined by their geographical locations; however, the microbial communities on the films were generally different from those in the soils. For the pulled data from the four landfill sites, the relative abundances of Bradyrhizobiaceae, Pseudarthrobacter, Myxococcales, Sphingomonas, and Spartobacteria were higher on films than in soils at the bacterial genus level. At the species level, operational taxonomic units classified as Bradyrhizobiaceae and Pseudarthrobacter in bacteria and Mortierella in fungi were enriched on the films. PICRUSt analysis showed that the predicted functions related to amino acid and carbohydrate metabolism and xenobiotic degradation were more abundant on films than in soils. These results suggest that specific microbial groups were enriched on the WPFs and may be involved in plastic degradation.

• Journal of Adhesion and Interface
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• v.15 no.4
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• pp.161-168
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• 2014

New self-assembled discotic liquid crystals have been prepared through single hydrogen bonding between phenol and pyridine moieties, and their liquid crystalline properties were investigated. For the construction of discotic structure, we used phloroglucinol as a core molecule and trans-4-alkoxy-4'-stilbazoles with systematically varied alkyl chain lengths as peripheral units. FTIR results showed that the intermolecular hydrogen bonds between core and peripheral molecules are successfully formed, and the stability of the hydrogen bond is strongly influenced by molecular ordering. Discotic complexes exhibited different liquid crystalline phases depending on the length of alkyl chains around the discotic mesogen. The discotic complexes with longer alkyl chains showed hexagonal columnar mesophases, while the other complexes formed nematic columnar mesophases. These results indicated that the type of mesophase structure was strongly dependent on the alkyl chain length around the aromatic core.

• Journal of the Korean Chemical Society
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• v.48 no.3
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• pp.229-235
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• 2004

For the study of hydrogen bonding phenomenon of high energetic compounds, we have been carried out a theoretical calculations for the nitromethane with the program Gaussian-98. The calculations at levels of restricted BLYP/6-311++G(d,p), B3LYP/6-311++G(d,p) and MP2/6-311++G have been performed to obtain molecular structures, hydrogen bonding effects and vibrational spectra of nitromethane monomer and dimer. The results show nitromethane is favored to make two hydrogen bonds between molecules and the nitromethane dimer is more stable than the monomer about 15.2, 19.4 and 32.6 kJ/mol for the BLYP, B3LYP, and MP2 level calculations, respectively.

• Journal of the Korean Chemical Society
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• v.55 no.2
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• pp.199-203
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• 2011

The title one-dimensional hydrogen-bonded coordination compound $[Cu^{II}(C_{13}H_{17}N_3OBr)(C_8H_5O_4)]{\cdot}2H_2O.CH_3OH$ has been synthesized and characterized by single crystal X-ray diffraction study. The monomeric unit contains a square-planar $Cu^{II}$ centre. The four coordination sites are occupied by a tridentate anionic Schiff base ligand (4-bromo-2-[(2-piperazin-1-yl-ethylimino)-methyl]-phenol) which furnishes an $N_2O$-donor set, with the fourth position being occupied by the oxygen atom of an adjacent terephthalate unit. Two adjacent neutral molecules are linked through intermolecular N-H---O and O-H---N hydrogen bonds and generate a dimeric pair. Each dimeric pair is connected with each other via discrete water and methanol molecules by hydrogen bonding to form a one-dimensional supramolecular network.

• Journal of Radiation Industry
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• v.6 no.1
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• pp.89-94
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• 2012

Three-dimensional network hydrogels were prepared by ${\gamma}$-irradiation of aqueous solutions of poly(vinyl alcohol) (PVA) and glycerol (Gly). Oven-drying was used to measure the gel fraction (G), hydration (H) or swelling behavior (S) of the prepared hydrogels. This study made a hypothesis that hydrogen bonds due to addition of glycerol and change of dry states such as freeze-drying (FD), room-drying (RD) and oven-drying (OD) acts on the G, H, and S. Interesting results on the hydrogen bonding effect in the prepared hydrogels are monitored at different drying conditions. The FD samples have a higher G values with increase in glycerol content as compared with the OD and RD samples. The formation of strong hydrogen bonding network among Gly molecules and hydrogel matrix was considered as the main driving force, resulting in the changes in the G, H, and S of the hydrogels under different drying conditions.

• Journal of the Korean Chemical Society
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• v.29 no.1
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• pp.31-37
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• 1985

N-Acetyl-1-phenylalanyl-1-phenylalanine methyl ester (APhPhMe), N-acetyl-l-phenylalanine methyl ester (APhMe) and N-acetyl-1-phenylalanyl-1-alanine methyl ester (APhAlMe) were used as model compounds to investigate a protein denaturation under various temperatures and pressures. Overall, the solubility of APhPhMe in water increased with increasing pressure and that of APhMe decreased. However, the solubility of APhAlMe was nearly same. The values of volume change of APhPhMe were -0.9, -1.47, -1.09, -1.52 ml/mole at 20, 30, 40 and 50$^{\circ}C$, respectively, and those of APhMe were +6.0, +7.0, +7.5 ml/mole at 20, 30 and 40$^{\circ}C$, respectively. But those of APhAlMe were nearly zero at the measured temperature. The experimental result seems to be explained by the hydrophobic interaction and hydrogen bond of peptide bonds. In the compounds which have only peptide bonds and which have both a pretty large hydrophobic group and a peptide bond in the molecules, the hydrogen bond between peptide bonds is more dominant than the hydrophobic interaction. However, when the number of peptide bond and hydrophobic group increase simultaneously, the hydrophobic interaction seems to be more dominant.

• Journal of the Korean Chemical Society
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• v.19 no.4
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• pp.233-239
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• 1975

The configuration of two oxime groups in cis-2-butenedialdioxime, unsymmetrical compound conjugated by three double bonds, is determined by a NMR study on the effects of the solvent, temperature and concentration; it is certain that, in solutions of usual conditions, the configuration exists as only "syn-syn". And the relative strengths of the hydrogen bond between these oxime groups and several solvents are compared and somc effects of the temperature and concentration are also considered. The several models of hydrogen bond between oxime and solvents are proposed; especially it is to be noted here that the hydrogen bond in pyridine solvent is not resulted from the interaction between a lone electron pair on nitrogen atom of pyridine and the hydroxyl proton of oxime, but the result of $\pi$-complex formed between the $\pi$-orbital of pyridine and the hydroxyl proton of the solute.