• Proceedings of the Korean Society of Precision Engineering Conference
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• 1992.04a
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• pp.190-199
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• 1992

Ultrasonic Spectroscopy technique, covering a wide frequency range, is one of the powerful Nondestructive Evaluation method for detection of microdefects and thickness measurement of thin film below the linit of ultrasonic distance resolution in various types of masterials and composites, provides a useful information that connot be obtained by a conventional measuring system using a single frequency. Results of computer simulation of multiple reflection wave were applied for particular cases : measurements of thickness and Ultrasonic wave velocities propagating normal to the surface in Acryle thin films can be evaluted by using the interference phenomenon, even dimensions of interest are smaller than the ultrasonic wavelength. The repeatability of the thickness measurement in 0.28 mm thin film was 10$\^$-3/.

• Progress in Superconductivity
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• v.2 no.2
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• pp.57-64
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• 2001

We have calculated the tunneling density of states (TDOS) of a metal/d-wave superconductor proximity junction, where the metal stands fur the normal metal, 5-wave superconductor, and d-wave superconductor. The tunneling direction is through the ab-plane of the d-wave superconductor. Because of the sign change in the order parameter experienced in the multiple Andreev reflection, there appears a finite TDOS at zero bias for duty geometry, which results in the anomalous zero bias conductance peak(ZBCP). For $d_{x2-y2}$ geometry, however, no TDOS peak appears at zero bias. We have calculated TDOS for various crystal orientation of HTSC and compared with the experimental conductance.

• Proceedings of the Optical Society of Korea Conference
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• 2001.02a
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• pp.54-55
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• 2001

Recently, there has been much interests in InGaN/GaN multiple-quantum-well (MQW) structures due to their applicability as optoelectronic devices such as light-emitting diodes (LEDs) and laser diodes [1]. Their ultrafast and physical properties are also of significant interests. Anomalously large acoustic phonon oscillations have been observed using ultrafast lasers in InGaN MQWs [2]. In this study, we have peformed femtosecond pump-probe experiments in the reflection geometry on 5 periods InGaN/GaN MQW LED structure with well width of 20$\AA$ and barrier width of 100$\AA$ at room temperature. (omitted)

• Proceedings of the KIEE Conference
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• 1994.07b
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• pp.1435-1438
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• 1994

The effects of Ge composition variation in $a-Si_{1-x}Ge_x:H$ alloy p-i-n solar cells on the physical properties and current density-voltage characteristics are analyzed by a new simulation modelling based on the update published experimental datas. The simulation modelling includes newly formulated density of gap density spectrum corresponding to Ge composition variation and utilizes the newly derived generation rate formulars which include the reflection coefficients and can apply to multijunction structures as well as single junction structure. The effects in $a-Si_{1-x}Ge_x:H$ single junction are analyzed through the efficiency, fill factor, open circuit voltage, short circuit current density, free carriers, trap carriers, electric field, generation rate and recombination rate. Based on the results analyzed in single junction structure, the applications to multiple junction structures are discussed and the optimal conditions reaching to a high performance are investigated.

• Journal of the Korea Institute of Military Science and Technology
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• v.7 no.2 s.17
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• pp.88-99
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• 2004

A development of a software on radar target signature analysis is presented in this paper The target signature includes Radar Cross Section(RCS) prediction, Range Profile(RP) processing and Inverse Synthetic Aperture Radar(ISAR) processing. Physical Optics(PO) is the basic calculation method for RCS prediction and Geometrical Optics(GO) is used for ray tracing in the field calculation of multiple reflection. For RP and ISAR, Fast Fourier Transform(FFT) and Matrix Pencil(MP) method were implemented for post-processing. Those results are integrated into two separate softwares named as Radar Target Signature Generator(RTSG) and Radar Target Signature Analyser(RTSA). Several test results show good performances in radar signature prediction and analysis.

• 한국정보디스플레이학회:학술대회논문집
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• 2009.10a
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• pp.1519-1522
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• 2009

We describe a 32" liquid-crystal display (LCD) with multi-touch sensing capability by integrating IR detector arrays onto the LED backlight plate. A transparent light guide is placed in front of the display screen, with IR LEDs disposed at its edges and emitting IR light into the light guide, the light is trapped by total internal reflection within the light guide to be as touch-sensing light. A physical contact with the acrylic plate surface will stimulate some trapped light to be escaped from the light guide and pass through LCD panel to be detected by the IR detectors. The touch-sensing LCD with this configuration can locate simultaneous multiple touche points on the touchable surface.

• Journal of Magnetics
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• v.14 no.1
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• pp.31-35
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• 2009

Herein, the Magneto-Optical Kerr Effect (MOKE) signal enhancement in nanostructures in investigated. It is well known that the MOKE signals of ferromagnetic thin films are enhanced with an additional dielectric layer due to multiple reflections. The MOKE signal is modulated with the additional dielectric layer thickness and is at a maximum when reflectivity is at a minimum. This is not always true in the nanostructures due to the contribution from the non-magnetic substrate portion, especially when substrate reflectivity is minimized and the dependence of the additional dielectric layer thickness for the nanostructure is changed in the case of the continuous thin film. We showed that the MOKE signal for nanostructures could be enhanced with a properly designed, dielectric layer in addition to the anti-reflection coated substrates.

• Proceedings of the Korean Institute of Interior Design Conference
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• 2008.05a
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• pp.179-183
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• 2008

A variety of design processes from 2D graphic to 3D models are meeting improved consumers' confidence of modern clients. However, the current design methods are limited to meet consumers' needs and express a design concept what a designer wants to show. Therefore the study here tries a test of hybrid space simulation combined with previous models and digital media technology, which can be used for multiple contents. The study can contribute to suggesting virtual space simulation that can help clients' spatial understanding in this media era and deliver emotional language of designers as well by utilizing the strong point of multi-sensible media.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.11b
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• pp.1323-1328
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• 2001

The theory of NAH is based on the assumption of reflection free. However, it is not always possible to meet this condition in many practical cases. Thus, a decomposition of direct and reflected fields is needed to apply NAH to reflective condition for noise problems. In addition, the decomposition of direct and reflected field can give acoustic characteristics of reflecting surfaces. This paper presents that in this condition the decomposition can also be successfully done by MUSIC(Multiple Signal Classification) power method and beamforming method, and that numerical simulation and real experiments verify its performance.

• Journal of the Korean Physical Society
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• v.73 no.10
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• pp.1512-1518
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• 2018

The problem of scalar wave scattering by a sphere on or near a planar substrate is analytically solved. The solution is a set of wave functions coming in the form of infinite series of spherical and plane waves. In air, the incident plane wave is either scattered by the sphere or reflected from the substrate. A part of these scattered or reflected waves propagate to the other object where it is reflected and scattered again. Such processes of scattering and reflection repeat in turn indefinitely to generate multiply scattered waves, which are represented in the corresponding terms in the infinite series. The term in the series can be arranged in a recognizable manner to explicitly reveal the involved process and the multiplicity of scattering.