• Transactions of Materials Processing
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• v.9 no.2
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• pp.128-139
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• 2000

Wrinkling is one of the major defects in sheet metal products and may be also attributable to the wear of the tool. The initiation and growth of wrinkles are influenced by many factors such as stress state, mechanical properties of the sheet material, geometry of the body, and contact condition. It is difficult to analyze the wrinkling initiation and growth considering the factors because the effects of the factors are very complex and the wrinkling behavior may show a wide variation for small deviations of the factors. In this study, the bifurcation theory is introduced for the finite element analysis of wrinkling initiation and growth. All the above mentioned factors are conveniently considered by the finite element method. The finite element formulation is based on the incremental deformation theory and elastic-plastic elements considering the planar anisotropy of the sheet metal. The proposed method is verified by employing a column buckling problem. And then, the initiation and growth of wrinkling in deep drawing of cylindrical cup are analyzed.

• Journal of Information Display
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• v.2 no.1
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• pp.1-4
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• 2001

We propose a dual in-plane parallel electrode structure of a vertical configuration of a helix-deformed ferroelectric liquid crystal (HDFLC) mode for better brightness than a single in-plain electrode case. This structure provides high brightness in addition to the analog gray scale capability, fast response, and wide-viewing characteristics. In contrast to a conventional HDFLC in a planar geometry, smectic layers arrange themselves parallel to the substrates and thus extremely uniform alignment of molecules in a large area is naturally achieved in our new configuration.

• Korean Journal of Crystallography
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• v.8 no.2
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• pp.124-126
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• 1997

The comples of [Ni(L)](ClO4)2 (L:3,5,10,12-tetramethyl-1,4,8,12-tetraazacyclotetradecane), C14H32Cl2N4NiO8, has a NiN4 square planar geometry and adopts a thermodynamically most stable trans-III conformation.

• ETRI Journal
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• v.16 no.1
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• pp.1-15
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• 1994

A computationally-efficient approach to the calculation of the transient field of an acoustic radiator was developed. With this approach, a planar or curved source, radiating either continuous or pulsed waves, is divided into a finite number of shifted and/or rotated versions of an incremental source such that the Fraunhofer approximation holds at each field point. The acoustic field from the incremental source is given by a 2-D spatial Fourier transform. The diffraction transfer function of the entire source can be expressed as a sum of Fraunhofer diffraction pattern of the incremental sources with the appropriate coordinate transformations for the particular geometry of the radiator. For a given spectrum of radiator velocity, the transient field can be computed directly in the frequency domain using the diffraction transfer function. To determine the accuracy of the proposed approach, the impulse response was derived using the inverse Fourier transform. The results obtained agree well with published data obtained using the impulse response approach. The computational efficiency of the proposed method compares favorably to those of the point source method and the impulse response approach.

• Bulletin of the Korean Chemical Society
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• v.33 no.12
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• pp.4069-4073
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• 2012

Metallacyclodimeric complexes of $[(Me_4en)Pd(L)]_2(ClO_4)_4$ ($Me_4en$ = N,N,N',N'-tetramethylethylenediamine; L = dimethylbis(4-pyridyl)silane (dmps), methylvinylbis(4-pyridyl)silane (mvps)) have been synthesized, and their structures have been characterized by X-ray single crystallography. The skeletal structures consist of one 20-membered metallamacrocycle, two 5-membered metallacycles, and four pyridyl groups. The local geometry around the palladium(II) ion approximates to a typical square planar arrangement with four nitrogen donors. Delicate difference in catalytic effects on hydrogenation was investigated based on the structure of catalyst and substrates.

• Proceedings of the KSRS Conference
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• 2002.10a
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• pp.59-64
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• 2002

This paper presents a method for line segment extraction for 3-d building reconstruction. Building roofs are described as a set of planar polygonal patches, each of which is extracted by watershed-based image segmentation, line segment matching and coplanar grouping. Coplanar grouping and polygonal patch formation are performed per region by selecting 3-d line segments that are matched using epipolar geometry and flight information. The algorithm has been applied to high resolution aerial images and the results show accurate 3-d building reconstruction.

• Bulletin of the Korean Chemical Society
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• v.11 no.5
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• pp.431-434
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• 1990

Template condensation reaction of diethylenetriamine, ethylenediamine, methylamine, and formaldehyde in the presence of Ni(II) or Cu(II) ion yields new saturated hexaaza macrobicyclic complexes $[Ni(C)]^{2+}\;and\;[Cu(C)]^{2+}$, where C is 8-methyl-1,3,6,8,10,13-hexaazabicyclo[11,2,1]hexad ecane. The macrobicyclic complexes contain one 1,3-diazacyclopentane ring and one methyl pendant arm in the ligand C and have square planar geometry with 5-6-5-6 chelate ring sequence. Synthesis, characterization, and the properties of the macrobicyclic complexes are described.

• Bulletin of the Korean Chemical Society
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• v.15 no.7
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• pp.549-553
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• 1994

The 2-(dimethylaminomethyl)thiophene (dmamt) complexes with copper(II) chloride and bromide were prepared and characterized by optical, EPR, XPS spectroscopies and magnetic susceptibility measurements. The low-energy absorption band above 850 nm and the relatively small EPR hyperfine coupling constant ($A_{//}{\simeq}$125 G) indicate the pseudotetrahedral site symmetry around copper(II) ion both in Cu(dmamt)$Cl_2$ and Cu(dmamt)$Br_2$ complexes. The higher satellite to main peak intensity of Cu $2P_{3/2}$ core electron binding energy in XPS spectra also supports the pseudotetrahedral geometry around the copper(II) ions having $CuNSX_2$ chromophores. The distortion from square-planar to pseudotetrahedral symmetry is likely to arise from the steric hindrance of the bulky dmamt ligand in the complex. Magnetic susceptibility study shows that these compounds follow Curie-Weiss law in the temperature range of 77-300 K with positive Weiss constant exhibiting the ferromagnetic interaction between copper(II) ions in solid state.

• Bulletin of the Korean Chemical Society
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• v.12 no.2
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• pp.219-224
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• 1991

New binuclear Ni(Ⅱ) and Cu(Ⅱ) complexes with various alkyl derivatives of 1,2-bis(1,3,6,8,10,13-hexaaza-1-cyclotetradecyl) ethane, in which two fully saturated 14-membered hexaaza macrocyclic subunits are linked together by an ethylene chain, have been synthesized by the one step template condensations of formaldehyde with ethylenediamine and appropriate primary alkyl amines in the presence of the metal ions. Each macrocyclic subunit of the double-ring macrocyclic complexes contains one alkyl pendant arm and has a square planar geometry with a 5-6-5-6 chelate ring sequence. The visible spectra and oxidation properties indicate that the metal-metal interaction of the binuclear complexes are not significant. Synthesis, characterization, and the properties of the complexes are presented.

• Bulletin of the Korean Chemical Society
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• v.13 no.3
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• pp.256-259
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• 1992

The 14-membered tetraaza macrocyclic ligand 1,8-diethyl-5,12-dimethyl-1,4,8,11-tetraazacyclote tradeca-4,11-diene(B) can be synthesized as its dihydroperchlorate salt by the one-pot reaction of 2-ethylaminoethylamine, methylvinyl ketone, and perchloric acid in absolute ethanol. The reaction of Ni(II) or Cu(II) ion and the salt yields $[M(B)]^{2+}$ (M = Ni(II) or Cu(II)), which reacts with $NaBH_4$ to produce $[M(D)]^{2+}$ (D = 1,8-diethyl-5,12-dimethyl-1,4,8,11-tetraazacyclote tradecane). The complexes $[M(L)]^{2+}$ (L = B or D) have planar geometry and contain two ethyl groups at the donor nitrogen atoms of the ligands. The red solids $[Cu(B)](X)_2(X)$ = $ClO_4-$ or $PF_6^-$) react with water molecules of atmospheric moisture to produce the purple solids in which water molecules are coordinated to the metal ion. Synthesis, characterization, and the properties of the new N-ethylated macrocyclic ligands and their Ni(II) and Cu(II) complexes are reported.