• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 가을 학술발표회 논문집
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• pp.621-624
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• 2003

The columns with large widths in out-of-plane direction fail showing the high nonlinearity of strain distribution. In order to predict the nonlinear behavior with reasonable accuracy in 2 dimensional analysis the material models taking this characteristic into account are indispensible. In this study equivalent softening model is developed which releases the same amount of energy at failure as that of 3-D analysis. Its validity is confirmed by comparing the analysis result with that of 3-D.

• 한국CDE학회논문집
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• 제14권2호
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• pp.122-128
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• 2009

The failure responses of adhesively bonded, hat stiffened structures are studied through numerical analysis using the finite element method. The responses are evaluated numerically for the bonded hat section/substrate structures containing different combinations of materials. It is studied what kind of material combinations causes the easier crack initiation in the structure. This study is conducted under plane strain conditions and J-integral via a commercial code ABAQUS as a total critical energy release criterion was used for observation on crack initiation. Also, the influence of adhesive on the structure is studied.

• The Journal of the Acoustical Society of Korea
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• 제17권2E호
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• pp.53-58
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• 1998

In this paper, we study the response of several anisotropic systems to buried transient line loads. The problem is mathematically formulated based on the equations of motion in the constitutive relations. The load is in form of a normal stress acting with arbitrary axis on the plane of monoclinic symmetry. Plane wave equation is coupled with vertical shear wave, longitudinal wave and horizontal shear wave. We first considered the equation of motion in reference coordinate system, where the line load is coincident with symmetry axis of the orthotrioic material. Then the equation of motion is transformed with respect to general coordiante system with azimuthal angle by using transformation tensor. The load is first described as a body force in the equations of the motion for the infinite media and then it is mathematically characterized. Subsequently the results for semi-infinite spaces is also obtained by using superposition of the infinite medium solution together with a scattered solution from the free surface. Consequently explicit solutions for the displacements are obtained by using Cargniard-DeHoop contour. Numerical results which are drawn from concrete examples of orthotropic material belonging to monoclinic symmetry are demonstrated.

• 한국전기전자재료학회논문지
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• 제27권7호
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• pp.428-432
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• 2014

The Hall factor in a two-dimensional device with indirect conduction valleys is calculated for several growth on various strain conditions. In the [001] or [111] growth direction, the two-dimensional constant energy surfaces of occupied valleys are shown to be isotropically distributed. However, in the [110] growth direction, the distribution of occupied valleys on the plane is not isotropic. This fact is the reason for the anisotropic Hall factor on the sample plane.

• Journal of Mechanical Science and Technology
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• 제15권10호
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• pp.1386-1397
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• 2001

In this paper, the plane elasticity equations are used to investigate the in-plane normal (mode I) and shear (mode II) behavior of a crack perpendicular to and terminating at the interface in bonded media with a graded interfacial zone. The interfacial Bone is treated as a nonhomogeneous interlayer with the continuously varying elastic modulus between the two dissimilar, homogeneous semi-infinite constituents. For each of the individual loading modes, based on the Fourier integral transform technique, a singular integral equation with a Cauchy kernel is derived in a separate but parallel manner. In the numerical results, the values of corresponding modes of stress intensity factors are illustrated for various combinations of material and geometric parameters of the bonded media in conjunction with the effect of the material nonhomogeneity within the graded interfacial zone.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2008년도 Techno-Fair 및 추계학술대회 논문집 전기물성,응용부문
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• pp.101-102
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• 2008

SF6 widely used as insulating gas is rising as the environment problem. For decreasing this greenhouse gas, electrical breakdown characteristics of vacuum with air are studied in non-uniform field. The gap of needle to plane was 0.5mm. The pressure of vacuum the range of 10^-4${\sim}$10^-5torr. The diameter of a plane made of the stainless steel is 150mm. As a result of the experiment, the breakdown voltage is increased about degree of vacuum increased. The electrode material influenced breakdown voltage in vacuum.

• 복합신소재구조학회 논문집
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• 제5권1호
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• pp.16-21
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• 2014

In the study, tensile, compression and in-plane tests about longitudinal direction of glass fiber were performed. Also, to obtain the material properties of GFRP fabric composite, tensile test was performed. All test were performed by the test method of ASTM. Maximum compressive strength was smaller than the maximum tensile strength at the longitudinal direction test results. Elastic modulus of the tensile and compressive was almost similar at the compression test results in the longitudinal direction. Based on the GFRP fabric composite test results, GF91 was showed good performance at maximum compressive, maximum strain and elastic modulus.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2001년도 하계학술대회 논문집
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• pp.656-659
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• 2001

We investigated the residual DC in the in-plane switching (IPS)-liquid crystal display(LCD) by voltage-transmittance (V-T) hysteresis method. Several IPS-LCD which have different concentrations of cynao LCs and different resistivities of fluorine LCs were fabricated. We found that the residual DC voltage of the IPS-LCD was decreasing with increasing concentration of cyano LCs and increasing with decreasing specific resistivity of fluorine LC materials. The residual DC voltage property can be improved by low molecular weight and high polarity of cyano LC.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집
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• pp.531-534
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• 2002

NiO buffer layers for YBCO coated conductors were deposited on hi-axially textured Ni substrates by MOCVD(metal organic chemical vapor deposition) method, using single solution source. To establish the processing condition, oxygen partial pressure and deposition temperature were changed. The surface orientation and degree of texture were estimated by X-ray diffraction, X-ray pole figure and atomic force microscopy. The FWHMs of in-plane and out-of-plane of the NiO films were about 10$^{\circ}$. The surface roughness was a function of deposition temperature. The AFM surface roughness of NiO films is in the range of 3∼10 nm, when NiO films was grown at 450∼530$^{\circ}C$.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2002년도 하계학술대회 논문집
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• pp.535-538
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• 2002

Cube-textured Ni substrates for YBCO coated conductors were fabricated by cold-rolling and annealing of Ni powder compacts. To establish the optimum sintering temperature, tensile test was performed for the Ni rod sintered at various temperatures. The Ni rods prepared at above 100$0^{\circ}C$ showed good mechanical properties due to the complete densification of the Ni rods. The Ni rods were rolled to final thickness of 100 ${\mu}{\textrm}{m}$ and then annealed at 100$0^{\circ}C$ for various annealing time for texture development. The texture analysis made by 2 $\theta$ scan and pole-figure showed that the cube texture was developed in a short time of a few munitues. The FWHM of in-plane and out of plane texture of the prepared Ni tapes was 8-10$^{\circ}$. The AEM surface roughness of the Ni tapes was as smooth as 3 nm.