• Journal of the Korean Vacuum Society
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• v.6 no.1
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• pp.50-60
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• 1997

Undoped, cobalt-doped and erbium-doped $ZnAl_2S_4, ;ZnAl_2Se_4, ;CdAl_2S_4, ;and;CdAl_2Se_4$ single crystals were grown by the chemical transport reaction method. The crystal structures, the lattice constants, the optical energy gaps, and the photoluminescence properties of these single crystals were investigated. Also, the optical transition mechanisms by the impurities of cobalt and erbium were identified from these results.

• Economic and Environmental Geology
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• v.29 no.4
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• pp.523-528
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• 1996

In Korean topography the behaviors of random fractals and multifractality are analytically and numerically studied on the mountain heights shown between $128{\sim}129^{\circ}E$ and $37{\sim}38^{\circ}N$. The phase transitions on the fractal structure are approximately found at the critical length $N_c=2000m$ from the values of standard deviations that it varies with both the longitudinal and latitudinal lengths. In the multifractal structure we assume that the mountain heights divided by the intervals of 20 m are located on the horizontal plane in two dimensional square lattice, and estimate the values of the generalized dimension and the scaling exponents by using the the box counting method for the three cases of square area ($1{\times}1km^2$, $2{\times}2km^2$, $4{\times}4km^2$).

• Journal of Surface Science and Engineering
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• v.12 no.3
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• pp.161-166
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• 1979

Theoretical and practical aspects are investigated for electrochemical behavious, plating processes and the structures of electrodeposit of Pb-Sn binary alloy plating through numerous literatures in this report. The anodic and cathodic electrode reaction mechanisms of Pb and Sn could co-deposit and make Pb-Sn alloy deposit from the results of cathode current density-cathode potential curves of Pb, Sn and Pb-Sn alloys in fluoborate solutions. The compositions of the best alloy plating solutions are obtained for the purpose of bearing, anticorrosion and solder plating. In general, the casting anodes of Pb-Sn alloys are used, but separated anodes of Pb and Sn pure metal are used in order to obtain the fine compositions of Pb-Sn alloy deposits. The electrodeposits of Pb-Sn alloy are in nonequilibrium state and saturated solid solutions. Thus, ${\beta}$-phase (Sn-phase) is precipitated by heat treatment. The texture and structure of the electrodeposit are associated with the surface energies of deposit lattice planes and with the cathode polarization. The electrodeposit of Pb-Sn alloy is shown as lamellar structure.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1999.10a
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• pp.395-402
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• 1999

This paper discusses the theoretical researches subject to elastic buckling problems of the structures. The purpose is to ensure the characteristic of buckling be true by arc-length method and the finite element method. The difficulties in processes calculating the equilibrium curve after buckling is to get the equilibrium owe near singular point at which the determinant of stiffness matrix is zero. The purpose of the load-displacement curve is to determine the buckling load of the structure, and further to get the information about the characteristic after buckling. Here, this paper expresses the incremental solution at particular point by the linear combination of both homogeneous mode and particular mode, then uses the method which gets the unknown parameter including this function, through trial-and-error method including modified N-R convergence process. Finally, this paper describes the multiple bifurcation of truss dome as the numerical examples according to this algorithm.

• Proceedings of the Korean Powder Metallurgy Institute Conference
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• 2006.09b
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• pp.910-911
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• 2006

We newly designed and manufactured a new arranging system for a three-dimensional artificial crystal of monosized micro particles. In this system, a robotic micro-manipulator accurately locates the spherical particle onto the lattice point, and subsequently fiber lasers micro-weld the contact points between the neighboring particles. Actually, one- and two-dimensional arrays were constructed using monosized tin particles with the diameter of 400 m. Moreover, due to optimization of the process parameters, we successfully constructed the artificial crystals of simple cubic and diamond structures. In particular, the diamond structure which can represent a large photonic band gap is expected to progress toward a practical photonic crystal device.

• Journal of Magnetics
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• v.16 no.3
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• pp.201-205
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• 2011

We performed total energy and electronic structure calculations for the basic ground state properties of Fe using the conventional generalized gradient approximation (GGA) and screened hybrid functionals as the form of the exchange-correlation functional. To that end, we calculated structural (equilibrium lattice constants, bulk moduli, and cohesive energies) and electronic (magnetic moments and densities of states) properties. Both functional calculations gave the correct ground state, the ferromagnetic bcc phase, in which the structural parameters agreed well with experimental results. However, the description of the cohesive energies and magnetic moments at the ground state exhibited different behavior from each other: the unusually small cohesive energy and large magnetic moment were observed in the screened hybrid functional calculations compared to the GGA calculations. The reason for the difference was examined by analyzing the calculated electronic structures.

• Bulletin of the Korean Chemical Society
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• v.30 no.4
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• pp.846-848
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• 2009

Two modifications of the ${\alpha}\;and\;{\beta}$ forms of propyl mercaptan nickel(II) cluster, [$Ni_6(SCH_2CH_2CH_3)_{12}$], have been synthesized and their crystal structures have been determined by single-crystal X-ray diffraction. The alkyl groups are away from $Ni_6$ ring in $\alpha$ form whereas they are near to the Ni atom in $\beta$ form. The distance of Ni-H in $\beta$ form [2.576(5) $\AA$] is much shorter than that in $\alpha$ form [3.101(2) $\AA$]. In the crystal lattice of $\beta$ form, the whole structure forms a flower shape.

• 한국논리학회:학술대회논문집
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• 2009.05a
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• pp.38-66
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• 2009

Weakening-free non-associative fuzzy logics, which are based on mica-norms, are introduced as non-associative substructural logics extending $GL_{e\bot}$ (Non-associative Full Lambek calculus with exchange and constants T, F) introduced by Galatos and Ono (cf. see [10, 11]). First, the mica-norm logic MICAL, which is intended to cope with the tautologies of left-continuous conjunctive mica-norms and their residua, and several axiomatic extensions of it are introduced as weakening-free non-associative fuzzy logics. The algebraic structures corresponding to the systems are then defined, and algebraic completeness results for them are provided. Next, standard completeness (i,e. completeness with respect to algebras whose lattice reduct is the real unit interval [0, 1]) is established for these logics by using Jenei and Montagna-style approach for proving standard completeness in [7, 18].

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.21 no.5
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• pp.453-457
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• 2008

In this thesis, piezoelectric properties and sintering properties of PCW-PNN-PZT+0.5 wt%$MnO_2$ ceramics adding $B_2O_3$ after creating the specimens with a general method. The lattice constant from the analysis of crystal structure showed that the crystal structure of ceramic features both rhombohdral and tetragonal structures and that the pychlore structure was decreased with the increase of the sintering temperature. The electromechanical coupling coefficient showed its maximum of 31 % in the sintered specimens at $1050^{\circ}C$, and its minimum of 20 % in the sintered specimens at $1150^{\circ}C$. The mechanical quality coefficient marked the maximum of 139 at the sintering temperature of $1150^{\circ}C$.

• Proceedings of the KIEE Conference
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• 2007.11a
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• pp.134-135
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• 2007

Two-dimensional photonic crystal structures have been fabricated on the chalcogenide material using holography lithography out of many production technical. The fabricated lattice can be observed obliquely by measuring diffraction pattern. The diffraction pattern of the microstructure has been observed with a He-Ne laser beam at wavelength of 632.8 nm. The diffracted beam has been analyzed by using the diffraction efficiency measurement method.