• Journal of the Korean Chemical Society
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• v.14 no.2
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• pp.147-153
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• 1970

Band assignments in the infrared absorption spectra of the four substituted Urea compounds, Fenuron (3-phenyl-1,1-dimethyl urea), OMU (3-cyclooctyl-1,1-dimethyl urea), Herban (3-(hexahydro-4,7-methanoidan-5-yl)-l,1-dimethyl urea), and Monuron (3-(p-chlorophenyl)-1,1-dimethyl urea), are made by analyzing the spectra obtained with various solvents. The results suggest that Fenuron and Monuron, each of which contain an unsaturated benzene ring, have a strong tendency to bond through both the amino group and the carbonyl oxygen. Herban and OMU, however, exhibit a much greater change in strength of the carbonyl bond than of the amino bond. It means that a strong hydrogen bonding occurs only at the carbonyl oxygen in the compounds.

• Proceedings of the KACD Conference
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• 2001.11a
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• pp.569.1-569
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• 2001

The purpose of this investigation was to determine the effect of dipping in tooth reserving solution on bond strength of 4-META/MMA-TBB dentin bonding system. The flattened dentin surface of bovine lower incisor was used for this investigation. The tooth were dipped in the tooth reserving solution (ViaSpan; Du Pont Pharmatical / Teeth Server "NEO";Neo Dental Chemical products CO/LTD, Japan/ Saline, Fuso Chemical CO, LTD, Japan) for 30 min.(omitted)

• Journal of the Korean Home Economics Association
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• v.25 no.1
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• pp.35-42
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• 1987

Since the 1930's, a rapid development of resin processing has contributed to making our clothing life convenient and rich. Wrinkle considered as the largest defect of cellulose fiber is generated from fixation of molecules which are divided by compression or crookedness. It can be protected by building a bridge between the molecules the joint combination of the inside of the fiber. The formaldehyde reactive resin which is used in processing resin is a chemical compound with more than 2 N-methylol or N-alkoxymethylol group and a chemical compound with N-methylol shows the property of W.W and D.P through the very complex bridge-bonding reaction under the OH group of cellulose and acid catalyst. However, if the processing is excessively carried out, resin-processed textile emits the formaldehyde when the bridge bonding agent reacts to amine type under the acid condition or the formaldehyde remains in the condition of non-reaction or the resin combinates by itself, or the methylol group of non-reactive resin is hydrolyzed due to the insufficient themomagnetic treatment.

• Bulletin of the Korean Chemical Society
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• v.33 no.1
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• pp.153-158
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• 2012

The hydrogenation of $AlB_2$-type BaGaGe exhibits a metal to insulator (MI) transition, inducing a puckering distortion of the original hexagonal [GaGe] layers. We investigate the electronic structure changes associated with the hydrogen-induced MI transition, using extended H$\ddot{u}$ckel tight-binding band calculations. The results indicate that hydrogen incorporation in the precursor BaGaGe is characterized by an antibonding interaction of $\pi$ on GaGe with hydrogen 1s and the second-order mixing of the singly occupied antibonding $\pi^*$ orbital into it, through Ga-H bond formation. As a result, the fully occupied bonding $\pi$ band in BaGaGe changes to a weakly dispersive band with Ge pz (lone pair) character in the hydride, which becomes located just below the Fermi level. The Ga-Ge bonds within a layered polyanion are slightly weakened by hydrogen incorporation. A rationale for this is given.

• Bulletin of the Korean Chemical Society
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• v.31 no.11
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• pp.3217-3220
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• 2010

The electronic structures and bonding configuration of histidine on Ge(100) have been investigated with various sample treatments using core-level photoemission spectroscopy (CLPES). Interpretation of the Ge 3d, C 1s, N 1s, and O 1s core level spectra being included in these systems revealed that both the imino nitrogen in the imidazole ring and the carboxyl group in the glycine moiety concurrently participate in the adsorption of histidine on a Ge(100) surface at 380 K. Moreover, we could clearly confirm that the imino nitrogen with a free lone pair in the imidazole group adsorbs on Ge(100) more strongly than the carboxyl group in the glycine moiety by examining systems annealed at various temperatures.

• Bulletin of the Korean Chemical Society
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• v.25 no.12
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• pp.1911-1916
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• 2004

The conformational preference of tetrahomodioxacalix[4]arenes with three different para substituents on the phenolic ring has been investigated by using ab initio molecular orbital theory (RHF/6-31$G^{\ast}$) and density functional theory (B3LYP/6-31$G^{\ast}$). The stability order is predicted to be cone > C-1,2-alternate > partial cone > 1,3-alternate > COC-1,2-alternate. The distorted cone conformation is found to be most stable in a gas phase and the calculated results are in agreement with the reported $^1$H NMR and X-ray experimental observations. The substitution of methylene with dimethyleneoxa bridges increases the size of the annulus of the molecule, its conformational mobility, and the number of hydrogen bonding patterns. The thermodynamic stability and the conformational characteristics of tetrahomodioxacalix[4]arenes are discussed in regards of the number of phenolic hydrogen bonding patterns and the polarity of a molecule. The substituent effects on the para position of the phenolic ring are also introduced.

• Journal of the Korean Chemical Society
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• v.59 no.2
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• pp.132-135
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• 2015

Bonding force and stiffness in amine-linked single-molecule junctions for Ag electrodes were measured using a home-built conducting atomic force microscope under ambient conditions at room temperature. For comparison, Au electrodes were used to measure the rupture force and stiffness of the molecular junctions. The traces of the force along with the conductance showed a characteristic saw-tooth pattern owing to the breaking of the metal atomic contacts or the metal-molecule- metal junctions. We found the rupture force and stiffness for Ag are smaller than those for Au electrodes. Furthermore, we observed that the force required to break the amine-Ag bond in the conjugated molecule, 1,4-benzenediamine, is smaller than in 1,4-butanediamine which is fully saturated. These results consist with the previous theoretical calculations for the binding energies of the nitrogen bonded to Ag or Au atoms.

• Bulletin of the Korean Chemical Society
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• v.31 no.4
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• pp.941-948
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• 2010

Ab initio and density functional theory methods have been employed to study all theoretically possible conformers of fluoroacetic acid. Molecular geometries and energetic of cis and trans monomers and cis dimers in gaseous phase have been obtained using HF, B3LYP and MP2 levels of theory, implementing 6-311++G(d,p) basis set. It was found that cis rotamers are more stable. In addition, it was found that in comparison with acetic acid the strength of hydrogen bonding in fluoroacetic acid decreased. The infrared spectrum frequencies and the vibrational frequency shifts are reported. Natural population and atom in molecule analysis performed to predict electrostatic interactions in the cyclic H-bonded complexes and charges. The proton transfer reaction is studied and activation energy is compared with acetic acid proton transfer reaction.

• Journal of the Korean Chemical Society
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• v.23 no.1
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• pp.15-19
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• 1979

The new concept of the Bonding and Antibonding Regions in the transition density space is developed from the Integral Hellmann-Feynman Theorem and the positive definiteness of the transition density. The unility of this concept is fully demonstrated for H2 system. It is expected that the nature of the electronic perturbation energy due to the change of nuclear configuration can be successfully understood by using this concept. Properties of the transition density is briefly discussed.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.07a
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• pp.173-176
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• 2000

In this paper, we investigated the surface degradation of HTV silicone rubber used for a polymeric insulator by UV irradiation. To study the surface ageing properties by W irradiation, we used the corona discharge charging and contact angle. Therefore, we observed the change of surface charge retention and decrease of surface hydrophobicity. Also, we discussed the chemical change in the surface range using the analytic equipment such as SEM, ATR-FTIR, ESCA. Therefore, it is found that the scissor of characteristic bonding and the reattachment of oxidant bonding was developed by UV rays radiation. As discussing the corona ischarge charging and the change of contact angle, it is found the effect of UV irradiation and the mechanism of chemical reaction