• Bulletin of the Korean Chemical Society
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• v.31 no.1
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• pp.162-167
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• 2010

We investigated the adsorption and desorption characteristics of benzene molecules on $Si(001)-2{\times}n$ surfaces using a variable-low temperature scanning tunneling microscopy. When benzene was adsorbed on a $Si(001)-2{\times}n$ surface at a low coverage, five distinct adsorption configurations were found: tight-binding (TB), standard-butterfly (SB), twisted-bridge, diagonal-bridge, and pedestal. The TB and SB configurations were the most dominant ones and could be reversibly interconverted, diffused, and desorbed by applying an electric field between the tip and the surface. The population ratios of the TB and SB configurations were affected by the benzene coverage: at high coverage, the population ratio of SB increased over that of TB, which was favored at low coverage. The desorption yield decreased with increasing benzene coverage and/or density of vacancy defect. These results suggest that the interaction between the benzene molecules is important at a high coverage, and that the vacancy defects modify the adsorption and desorption energies of the benzene molecules on Si(001) surface.

• Bulletin of the Korean Chemical Society
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• v.7 no.4
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• pp.267-271
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• 1986

The ionomeric blend and the ionic aggregation studies by using a Fourier-transform infrared spectroscopy(FT-IR) are presented. Two ionomers were prepared, one is barium polyacrylate and the other is barium polystyrenesulfonate. The blend of the two ionomers of the barium salts shows intermolecular ionic interaction between the carboxylated ionomer and the sulfonated ionomer. This interaction leads to considerable differences between the spectrum of the blend and the sum of the spectra of the pure ionomers. From our results, it is shown that ionic interactions must play an important role in the compatibility of the two ionomers. In the ionic aggregation study, the bands due to asymmetric stretching mode of carboxylate anion(COO-) in the carboxylated ionomer and the ionomer blend increase in intensity with increasing the divalent barium cations. These results indicate the formation of ion pairs. The doublet due to the asymmetric stretching modes of the carboxylate anion(COO-) is concerned with a sort of local structure found in the ion aggregation. By considering a possible structure for multiplets in the blend, the spectral splitting and the frequency shift are well explained.

• Journal of the Korean Chemical Society
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• v.13 no.4
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• pp.273-280
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• 1969

The MO's of maleic anhydride are calculated using the parameter values, $h_{o}$.= 1, $h_{o}$:= 2, $k_{c=o}$= 1, $k_{c-o}$= 0.8, and ${\delta}_{{\alpha}_n}=2{\times}(0.3)^n$. With these MO's the interaction energies of the photochemical reaction of maleic anhydride (MA) with benzene are calculated using intermolecular orbital theory. It is shown that there are cases where the interaction energy includes a constant term and this term takes a great role in the photochemical interaction energy, and that with the calculated interaction energies the reaction mechanism is quite well explained. And it is proved that the photochemical reaction is possible for the second addition step of MA to benzene, and that the MA-benzene adduct should have the well-known stereochemical structure.

• Molecules and Cells
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• v.27 no.1
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• pp.39-45
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• 2009

Ligand-dependent or independent oligomerization of receptor protein tyrosine kinase (RPTK) is often an essential step for receptor activation and intracellular signaling. The novel oncogene with kinase-domain (NOK) is a unique RPTK that almost completely lacks an ectodomain, expresses intracellularly and activates constitutively. However, it is unknown whether NOK can form oligomer or what function oligomerization would have. In this study, two NOK deletion mutants were generated by either removing the ectodomain ($NOK{\Delta}ECD$) or including the endodomain (NOK-ICD). Co-immunoprecipitation demonstrated that the transmembrane (TM) domain of NOK was essential for its intermolecular interaction. The results further showed that NOK aggregated more closely as lower order oligomers (the dimer- and trimer-sized) than either deletion mutant did since NOK could be crosslinked by both Sulfo-EGS and formaldehyde, whereas either deletion mutant was only sensitive to Sulfo-EGS. Removing the NOK TM domain (NOK-ICD) not only markedly promoted higher order oligomerization, but also altered the subcellular localization of NOK and dramatically elevated the NOK-mediated constitutive activation of extracellular signal-regulated kinase (ERK). Moreover, NOK-ICD but not NOK or $NOK{\Delta}ECD$ was co-localized with the upstream signaling molecule RAS on cell membrane. Thus, TM-mediated intermolecular contacting may be mainly responsible for the constitutive activation of NOK and contribute to the autoinhibitory effect on RAS/MAPK signaling.

• Journal of the Korean Chemical Society
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• v.40 no.3
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• pp.187-195
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• 1996

Ab initio SCF calculations have been carried out for the five conceivable trimers formed between one hydrogen cyanide and two hydrogen fluorides using a basis set of TZ＋P quality. Several ground state properties of these trimeric complexes have been evaluated, and compared with those of isolated monomers and appropriate dimers. Computed equilibrium geometries, stabilization energies, and dipole moments are given in order to suppliment the available experimental data. At this level of approximation, intramolecular bond distances are consistently shorter than experimental ones. However, intermolecular distances upon complex formation, and dipole moments are overestimated compared with experimental ones. HCN$(HF)_2$ trimer appears to be the most favourable among the five kinds of trimer complex, and also more stable than $(HCN)_2HF$. The typical features of the non-additivity of intermolecular interaction are relatively strong in the HCN$(HF)_2$ trimer.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.2678-2683
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• 2007

The interaction between metal molecules and liquid metal molecules was modeled in the molecular scale and simulated by the molecular dynamics method in order to understand behaviors of the cluster on metallic surface in collision process. Lennard-Jones potential had been used as intermolecular potential, and only attraction 때 d repulsion had been used for the behavior of the cluster on the metal surface. As results, the behavior of the cluster was so much influenced by the cluster of liquid metal temperature and function of molecules forces, such as attraction and repulsion, in the collision progress. These results of simulation will be the foundation for the micro fabrication manufacturing by using spray application technology.

• Proceedings of the KSME Conference
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• 2007.05b
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• pp.1912-1915
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• 2007

The disjoining pressure is critical in modeling the transport phenomena in small scales. They are very useful in characterizing the non-continuum effects that are not negligible in heat and mass transports in the film of less than submicro-scales. We present he disjoining pressure of thin film absorbed on solid substrate using Molecular Dynamics Simulation (MD). The disjoining pressure with respect to the film thickness is accurately calculated in the resolution of a molecular scale. The characteristics of the pressure are discussed regarding the molecular nature of the fluid system like molecular diameter and intermolecular interaction. Also, the MD results are compared with those based on the macroscopic approximation of the slab-like density profile. Significant discrepancy is observed when the effective film thickness is less than several molecular diameter

• Journal of Sensor Science and Technology
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• v.13 no.4
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• pp.316-320
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• 2004

The possibility to use powder consisting of fullerite microcrystallines as a device sensitive to the external axial mechanical load is considered. We suppose that the change of conductivity of fullerite microcrystalline powder as a function of external mechanical stress will be useful for the creation of nanoscale devices of sensor electronics. This new effect based on changing of intermolecular distance between fullerene molecules due to the action of external mechanical force, which can change the distance between fullerene molecules because of weak van der Waals interaction exists. The founded effect is quite linear and sensitive to external mechanical stress is better then in well-known pressure transducers is based on silicon technology.

• Journal of Life Science
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• v.17 no.9 s.89
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• pp.1303-1307
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• 2007

A tumor suppressor, merlin is a member of ERM family proteins. It consists of N-terminal FERM domain, ${\alpha}-helical$ region, and C-terminal domain. Alternative splicing of merlin's mRNA generates two isotypes of merlin. Isotype I, which has exon17 at the C-terminus instead of exon16 in isotype II, is known to have tumor suppressor activity. Like other ERM proteins, the C-terminal domain of merlin isotype I interacts to its FERM domain. That of isotype II, however, was reported not to bind FERM domain despite the large common part of C-terminal domain, which possibly binds FERM domain. Here, we show the binding of FERM domain to both C-terminal domains of merlin's two isotypes by isothermal titration calorimetry. These results support that merlin isotype II also can form a closed conformation or a multimer by intramolecular or intermolecular interactions using their FERM domain and C-terminal domain.

• Food Science and Biotechnology
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• v.18 no.4
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• pp.910-916
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• 2009

Present work was focused on the influence of methylcellulose (MC) on steady rheology of wheat gliadin solution and the properties of glycerol plasticized gliadin films. The presence of MC below 0.99 wt% improved viscosity and flow activation energy of the 10 wt% gliadin solution significantly. In the casting films containing 0.2 g glycerol/g dry protein, the MC component aggregated in the gliadin matrix. The blend films containing less than 7.7 wt% MC exhibited higher Young's modulus (E) and tensile strength (${\sigma}_b$) and lower elongation at break (${\epsilon}_b$) in comparison with the pure gliadin film, which was related to the intermolecular interaction between MC and gliadins, the brittle fracture of the aggregated MC component, and the increase in glass transition temperature ($T_g$) of the gliadin phase. Increasing MC content led to a slight increase in water vapor permeability (WVP) without significant influence on the moisture absorption (MA).