• Journal of Ocean Engineering and Technology
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• v.23 no.1
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• pp.146-151
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• 2009

In this paper, a weight function theory for the calculation of the mode III stress intensity factor in a rectilinear anisotropic body is formulated. This formulation employs Lekhnitskii's formalism for two dimensional anisotropic materials. To illustrate the method used for the weight function theory, we calculated the mode III stress intensity factor in a single edge-notched configuration.

• Proceedings of the KSME Conference
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• 2000.04a
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• pp.115-120
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• 2000

This paper examines that it is possible to apply RWCIM for determining eigenvector coefficients associated with eigenvalues for V-notched cracks in anisotropic dissimilar materials using the complex stress function. To verify the RWCIM algorithm, two tests will be shown. First it is performed to ascertain whether predicted coefficients associated with eigenvectors is obtained exactly. Second, it makes an examination of the state of stress for FEM and RWCIM according to a number of eigenvectors at a location far away from the V-notched crack tip.

• Journal of the Korean Society for Nondestructive Testing
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• v.31 no.6
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• pp.635-641
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• 2011

In ultrasonic testing of dissimilar metal welds, application of phased array technique in terms of incident beam focusing is not easy because of complicated material structures formed during the multi-pass welding process. Time reversal(TR) techniques can overcome some limitations of phased array since they are self-focusing that does not depend on the geometrical and physical properties of testing components. In this paper, we test the possibility of TR focusing on a defect within anisotropic, heterogeneous austenitic welds. A commercial simulation software is employed for TR focusing and imaging of a side-drilled hole. The performance of time reversed adaptive focal law is compared with those of calculated focal laws for both anisotropic and isotropic welds.

• Journal of the Korean Society for Aeronautical & Space Sciences
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• v.33 no.9
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• pp.48-55
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• 2005

In this paper, wrinkling behavior for anisotropic membrane was studied. The analyses were done by using membrane elements and the wrinkling was accounted for by the penalty parameter modified material modeling which was implemented to ABAQUS as a user subroutine. The wrinkle model was applied to corner-loaded square membranes in which the effect of the diameter of steel pin, edge cut-off length and the magnitude of shear moduli on the wrinkling was investigated.

• Proceedings of the International Microelectronics And Packaging Society Conference
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• 2002.09a
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• pp.21-30
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• 2002

According the difference of flex substrate, (reel tape), there are three kind assembly types of LCD driver IC is COG, TCP and COF, respectively. The TCP is the maturest in these types for stability of raw material supply and other specification. And TCP is the major assembly type of LCD driver IC and the huge demand from Taiwan's large TFT LCD panel house since this spring. But due to its package structure and the raw material applied in this package, there is some limitation in fine pitch application of this package type, (TCP). So, COF will be very potential in compact and portable application comparison with TCP in the future. There are three kinds assembly methods in COF, one is ACF by using the anisotropic conductive film to connect the copper lead of tape and gold bump of IC, another is eutectic bonding by using the thermo-pressure to joint the copper lead of tape and gold bump of IC, and last is NCP by using non-conductive paste to adhere the copper lead of tape and gold bump of IC. To have a global realization, this paper will briefly review the status of Taiwan's large TFT panel house, the internal driver IC design house, and the back-end assembly house in the beginning. The different material property of raw material, PI tape is also compared in the paper. The more detail of three kinds of COF assembly method will be described and compared in this paper.

• Journal of the Korean Geotechnical Society
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• v.28 no.4
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• pp.35-42
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• 2012

This paper evaluates the effect of anisotropic conductivity on the seepage face and reliability index of an homogeneous dam with and without toe drain. The analysis are conducted under steady state saturated-unsaturated seepage condition using finite element method. Various anisotropic conductivity ratios were interpreted under such conditions as the vertical conductivity is reduced while the horizon conductivity is fixed. The shear strength of soil is defined by the modified Mohr-Coulomb failure criterion. The analysis results demonstrate that the length of seepage face and reliability index at the downstream and upstream of the dam increase with an increasing anisotropic ratio. These results of the seepage face and reliability index, however, depend on the total head difference between the upstream slope and downstream toe. The difference in seepage face and reliability index is attributed to the different equipotential head with different anisotropic ratios of the dam material.

• International Journal of Highway Engineering
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• v.11 no.1
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• pp.187-194
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• 2009

This paper presents the development of transfer function accounting for cross-anisotropic behavior of aggregate base material for the pavement thickness design. The stress distributions predicted by nonlinear cross-anisotropic finite element program were realistic by eliminating excessive tensile stress at the bottom of the base layer and the critical pavement responses predicted by nonlinear cross-anisotropic model are higher than those predicted by linear or nonlinear isotropic models (Kim, 2004, Kim et at., 2005). Since the previously developed transfer functions such as Asphalt Institute and Chevron models, etc. were based on the critical responses obtained from linear isotropic model, those equations are not appropriate for the thickness design nonlinear cross-anisotropic base behavior. Therefore, the development of usable transfer functions for nonlinear cross-anisotropic model is ever more important. When the newly developed transfer functions were compared with AASHTO method for the thickness design, the newly developed transfer functions produce approximately 25mm reduced UAB thickness in AASHTO thickness design and this illustrates that linear isotropic model results in more conservative pavement design.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.33 no.1
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• pp.21-24
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• 2020

We investigated a solution-driven Yttrium Tin Oxide (YSnO) film that was imprinted using a parallel nanostructure as a liquid crystal (LC) alignment layer. The imprinting process was conducted at the annealing temperature of 100℃. To evaluate the effect of this process, we conducted surface analyses including atomic force microscopy (AFM). During imprinting, the surface roughness was reduced, and anisotropic characteristics were observed. Planar LC alignment was observed at a pretilt angle of 0.22° on YSnO film. Surface anisotropy induced by imprinting method forces LC to align along the direction of the parallel nanostructure, which is an alternative to conventional polyimide treated using a rubbing process.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2000.04b
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• pp.112-116
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• 2000

This paper presents anisotropic ethcing characteristics of single-crystal silicon in tetramethylammonium hydroxide(TMAH):isopropyl alcohol(IPA) solutions containing pyrazine. With the addition of IPA to TMAH solutions, etching characteristics are exhibited that indicate an improvement in flatness on the etching front and a reduction in undercutting, but the etch rate on (100) silicon is decreased. The (100) silicon etch rate is improved by the addition of pyrazine. An etch rate on (100) silicon of $0.8\;{\mu}m/min$, which is faster by 13 % than a 20 wt.% solution of pure TMAH, is obtained using 20 wt.% TMAH:0.5 g/100 ml pyrazine solutions, but the etch rate on (100) silicon is decreased if more pyrazine is added. With the addition of pyrazine to a 25 wt.% TMAH solution, variations in flatness on the etching front were not observed and the undercutting ratio was reduced by 30 ~ 50 %.

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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• 2001.07a
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• pp.859-862
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• 2001

This study describes a selective Ag etching solution for use with pattern on the surface of copper. This etching solution uses potassium iodide and potassium sulfate as the ligand that coordinates to the metal ions and ferricyanide as the oxidant. The etching rate was depended on the concentration of co-ligands and time. But the etching rate wasn't depended on the pH(2∼6), and oxidant(K$_3$Fe(CN)$\_$6/). Complete etching of silver can be achieved rapidly within 90sec for 4.46${\mu}$m thick metal films when aqueous solutions containing K$_3$Fe(CN)$\_$6/, K$_2$S$_2$O$\_$8/ and KI was used. This etching solution was characteristic of anisotropic etching.