• Coupled systems mechanics
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• v.7 no.3
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• pp.255-268
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• 2018

Stability of MBC1, a specific matching boundary condition, is proved for atomic simulations of a diatomic chain. The boundary condition and the Newton equations that govern the atomic dynamics form a coupled system. Energy functions that decay along with time are constructed for both the boundary with the same type atoms and the one with different type atoms. For a nonlinear chain, MBC1 is also shown stable. Numerical verifications are presented. Moreover, MBC1 is proved to be stable for a two dimensional square lattice.

• Ceramist
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• v.21 no.2
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• pp.29-37
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• 2018

In order to overcome the problems of existing low-dimensional materials (carbon nanotubes, graphene, transition metal dichalcogenides, etc) researches on new 1D materials have been studied. In the case of $LiMo_3Se_3$ and $Mo_6S_{9-x}I_x$, continuous researches have been carried out for 3D bulk synthesis and atomic scale dispersion. Recently, quantum confinement effect of $LiMo_3Se_3$ and bio-stability of $Mo_6S_{9-x}I_x$ have been proven and various applications have started to be studied. In addition, device application results using new 1D materials such as $Sb_2Se_3$ (optoelectronic devices using the property of effectively reducing exciton decay due to no dangling bond) and $VS_4$ (electrochemical energy storage using the space between 1-D nanostructures) have been reported very importantly. Therefore, it can be claimed that it has reached a very important time to find and synthesize new 1D materials and to report various characteristics not existing.

• Nuclear Engineering and Technology
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• v.25 no.4
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• pp.539-547
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• 1993

A stochastic approach using continuous time Markov process is presented to model the one-dimensional nuclide transport in fractured rock media as a further extension for previous works［1-3］. Nuclide transport of decay chain of arbitrary length in the single planar fractured rock media in the vicinity of the radioactive waste repository is modeled using a continuous time Markov process. While most of analytical solutions for nuclide transport of decay chain deal with the limited length of decay chain, do not consider the case of having rock matrix diffusion, and have very complicated solution form, the present model offers rather a simplified solution in the form of expectance and its variance resulted from a stochastic modeling. As another deterministic way, even numerical models of decay chain transport, in most cases, show very complicated procedure to get the solution and large discrepancy for the exact solution as opposed to the stochastic model developed in this study. To demonstrate the use of the present model and to verify the model by comparing with the deterministic model, a specific illustration was made for the transport of a chain of three member in single fractured rock medium with constant groundwater flow rate in the fracture, which ignores the rock matrix diffusion and shows good capability to model the fractured media around the repository.

• Journal of the Korean Mathematical Society
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• v.59 no.5
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• pp.927-944
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• 2022

Let $\vec{p}{\in}(0,\;1]^n$ be an n-dimensional vector and A a dilation. Let $H^{\vec{p}}_A(\mathbb{R}^n)$ denote the anisotropic mixed-norm Hardy space defined via the radial maximal function. Using the known atomic characterization of $H^{\vec{p}}_A(\mathbb{R}^n)$ and establishing a uniform estimate for corresponding atoms, the authors prove that the Fourier transform of $f{\in}H^{\vec{p}}_A(\mathbb{R}^n)$ coincides with a continuous function F on ℝⁿ in the sense of tempered distributions. Moreover, the function F can be controlled pointwisely by the product of the Hardy space norm of f and a step function with respect to the transpose matrix of A. As applications, the authors obtain a higher order of convergence for the function F at the origin, and an analogue of Hardy-Littlewood inequalities in the present setting of $H^{\vec{p}}_A(\mathbb{R}^n)$.

• Journal of the Korean Chemical Society
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• v.7 no.1
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• pp.74-84
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• 1963

Hexamethylenediamine dihydroiodide is monoclinic, with cell dimensions $a=4.85{\AA}$, $b=12.77{\AA}$, $c=9.73{\AA}$, ${\beta}=91.5^{\circ}$ The space group is $P2_1/c$, with two molecules per unit cell. It has a center of symetry in the molecule. All atomic positions are determined by means of a two-dimensional patterson synthesis and fourier synthesis. The C-N bond distance is $1.48{\AA}$ and the C-C bond distances are lying between $1.55{\AA}$, and $1.59{\AA}$. The iodine atom is bonded by hydrogen bridges of $3.59{\AA}{\pm}0.1{\AA}$ to nitrogen atoms and surrounded by three nitrogen atoms. The hexamethylenediamine chain is zigzag in the hexamethylenediamine dihydrochloride molecules though, it is not zigzag in the hexamethylenediamine dihydroiodide.

• Journal of the Korean Electrochemical Society
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• v.5 no.3
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• pp.143-152
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• 2002

The growth of Polypyrrole film has been investigated during electropolymerization in an aqueous solution on bare and SAM modified gold electrodes by in-situ EQCM and ex-situ AFM. According to the result of cyclic voltammetry measurements, in the case of a bare gold electrode, the electrochemical deposition of polypyrrole were dependent on the limiting oxidative potential, but not on scan numbers. When the limiting potential higher than 0.8 V was applied on the electrode, the amount of polypyrrole deposited on a gold electrode was rapidly increased and the abnormal mass change attributed to the rearrangement of polypyrrole films was observed as the scan number increased. The polypyrrole film Prepared on electrodes modified with 1-dodecanethiol SAM or thiophene SAM grew 3-dimensionally with the rearrangement of film. However, in the case of BPUS SAM, 2-dimensional layer-by-layer growth of film was observed without the rearrangement of film. AFM images showed films with chain-shaped and/ or donut-shaped polymers when grown rapidly and a wrinkled film at the steady state condition.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.18 no.5
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• pp.407-413
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• 2005

Ion implantation provides a unique way to modify the mechanical, optical and electrical properties of polymer by depositing the energy of ions in the material on the atomic scale. Implantation of ions into the polymers generally leads to a radiation damage, which, in many cases, modifies the properties of the surface and bulk of the material. These modifications result from the changes of the chemical structure caused in their turn by changing the chemical bonding when the incident ions cut the polymer chains, breaks covalent bonds, promotes cross-linking, and liberates certain volatile species. We studied the relation among the linear energy transfer (LET) and changes of surface microstructure and surface resistivity on PPS material using the high current ion implantation technology The surface resistivity of nitrogen implanted PPS decreased to $10^{7}{\Omega}/cm^{2}$ due to the chain scission, cross linking, ${\pi}$ electron creation and mobility increase. In this case, the surface conductivity depend on the 1-dimensional hopping mechanism.