• Proceedings of the KSME Conference
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• 2004.11a
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• pp.1158-1161
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• 2004

Shell shaped hollow carbon nanoparticles are synthesized in the oxygen-hydrogen diffusion flame with $C_{2}H_{2}$ as precursor when it is irradiated with $CO_{2}$ laser of certain power. Below this power of laser, we couldn't get any other but amorphous soot. This shell shaped hollow carbon nanoparticles shows outer wall of high degree of crystallinity with void space inside of itself. And size distribution of these nanoparticles is measured with TEM image analysis. Also the structural comparison between this carbon nanoparticle and soot is done by Raman and XRD measurement. These results show this carbon nanoparticles are of grapheme structure, which means it has good crystallinity when compared with soot.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.4 no.4
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• pp.28-33
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• 2005

Recently, trends of TFT-LCD toward larger scale and thinner thickness continue. so, demands of Light Guide Panel (LGP) which is to substitute for prism sheet are appeared. Functions of LGP obtaining polarization of light of the prism sheet as well as the incidence and reflection of light are demanded. This prism type LGP to complete functions of the existing LGP and polarization at once must be supported by micro machining technology of LGP surface. In this research, the machining characteristics of the various materials were analysed by shaping using V-shaped single crystal diamond tool. The characteristics are machined surface, machining force due to the variation of cutting depth. Used specimens are engineering materials, which are 6:4 brass, oxygen-free copper, Al6061, PC, PMMA. The FFT analysis of the measured cutting force was conducted. The cutting characteristics were analyzed and the optimum cutting conditions with materials were established.

• Transactions on Electrical and Electronic Materials
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• v.6 no.3
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• pp.110-114
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• 2005

We present a micro fluxgate magnetic sensor having solenoid coils and racetrack shaped magnetic core, which was designed to decrease the .operating power and magnetic flux leakage. Electroplated copper coils of $6\;{\mu}m$ thickness and the core of $3\;{\mu}m$ thickness were separated by benzocyclobutane (BCB) having a high insulation and good planarization characters. Permalloy $(Ni_{0.8}Fe_{0.2})$ as a magnetic core was also electroplated under 2000 gauss to induce the magnetic anisotropy. The core had the high DC effective permeability of $\~1,300$ and coercive field of $\~0.1$ Oe. The fabricated fluxgate sensor had the very small actual size of $3.0\times1.7\;mm^2$. The fluxgate sensor with a racetrack shaped core had the high sensitivity .of $\~350$ V/T at excitation condition of 3 $V_{P-P}$ and 2 MHz square wave. When two fluxgates were perpendicularly aligned in terrestrial field, their two-axis output signals were very useful to commercialize an electronic azimuth compass for the portable navigation system.

• ETRI Journal
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• v.18 no.3
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• pp.171-179
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• 1996

Fully passivated low noise AlGaAs/InGaAs/GaAs pseudomorphic (PM) HEMT with wide head T-shaped gates were fabricated by dose split electron beam lithography (DSL). The dimensions of gate head and footprint were optimized by controlling the splitted pattern size, dose, and spaces of each pattern. We obtained stable T-shaped gate of $0.15{\mu}m$ gate length with $1.35{\mu}m-wide$ head. The maximum extrinsic transconductance was 560 mS/mm. The minimum noise figure measured at 18 GHz at $V_{ds}=2V andI_{ds}=17mA$ was 0.41 dB with associated gain of 8.19 dB. At 12 GHz, the minimum noise figure and an associated gain were 0.26 and 10.25 dB, respectively. These noise figures are the lowest values ever reported for GaAs-based HEMTs. These results are attributed to the extremely low gate resistance of wide head T-shaped gate having a ratio of the head to footprint dimensions larger than 9.

• Progress in Superconductivity
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• v.14 no.2
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• pp.102-105
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• 2012

We are developing meander-shaped metallic magnetic calorimeters using micro-fabrication methods. A planar Nb coil in a meander shape was fabricated on a Si substrate. The coil was designed to have a persistent current using a metal heater evaporated on a part of the coil. A paramagnetic sensor, $5{\mu}m$ thick Au:Er foil, was glued on top of the meander structure with epoxy. The magnetization and heat capacity were measured at different temperatures, and applied field currents matched well with expected values. The detector showed an energy resolution of 4 keV FWHM for the 5.5 MeV alpha particles.

• Journal of Electrical Engineering and Technology
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• v.11 no.6
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• pp.1880-1885
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• 2016

This study aims to design a zonal lumen for parking garage LED lightings of a slim appearance and 20 W/2,000 lm capacity and to fabricate a lighting luminaire accordingly. The frame is of a one-dimensional bar type with a reverse V-shaped section, with LED chips arranged along both sides. To maximize the $60^{\circ}$ to $80^{\circ}$ zonal lumen, the geometric structure was designed with the apex of the reverse V-shaped section at $40^{\circ}$ and both sides at $70^{\circ}$. As for the LED light source, focusing lenses with narrower full-width half-maximum (FWHM) in luminous intensity were used. A ray-tracing simulation method was utilized for the zonal lumen simulation of the given structure. An actual hardware of luminaire based on the simulation results was fabricated and characterized. The suggested model is meant to develop LED lightings with a proper level of zonal lumen required in parking garages.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2006.10a
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• pp.407-408
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• 2006

• JSTS:Journal of Semiconductor Technology and Science
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• v.14 no.4
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• pp.365-375
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• 2014

This paper proposes an abnormal V-shaped-error-free non-blind deconvolution technique featuring an adaptively segmented forward-problem based iterative deconvolution (ASDCN) process. Unlike the algebraic based inverse operations, this eliminates any operations of differential and division by zero to successfully circumvent the issue on the abnormal V-shaped error. This effectiveness has been demonstrated for the first time with applying to a real analysis for the effects of the Random Telegraph Noise (RTN) and/or Random Dopant Fluctuation (RDF) on the overall SRAM margin variations. It has been shown that the proposed ASDCN technique can reduce its relative errors of RTN deconvolution by $10^{13}$ to $10^{15}$ fold, which are good enough for avoiding the abnormal ringing errors in the RTN deconvolution process. This enables to suppress the cdf error of the convolution of the RTN with the RDF (i.e., fail-bit-count error) to $1/10^{10}$ error for the conventional algorithm.

• IEIE Transactions on Smart Processing and Computing
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• v.2 no.4
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• pp.216-225
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• 2013

This paper discusses the issues regarding an abnormal V-shaped error confronting algebraic-based deconvolution process. Deconvolution was applied to an analysis of the effects of the Random Telegraph Noise (RTN) and Random Dopant Fluctuation (RDF) on the overall SRAM margin variations. This paper proposes a technique to suppress the problematic phenomena in the algebraic-based RDF/RTN deconvolution process. The proposed technique can reduce its relative errors by $10^{10}$ to $10^{16}$ fold, which is a sufficient reduction for avoiding the abnormal ringing errors in the RTN deconvolution process. The proposed algebraic-based analyses allowed the following: (1) detection of the truncating point of the TD-MV distributions by the screening test, and (2) predicting the MV-shift-amount by the assisted circuit schemes needed to avoid the out of specs after shipment.

• Journal of the Optical Society of Korea
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• v.18 no.1
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• pp.9-14
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• 2014

We numerically investigate the effect of sunlight polarization on the absorption efficiency of V-shaped organic solar cells (VOSCs) using the finite element method (FEM). The spectral distribution of absorbance and the spatial distribution of power dissipation are calculated as a function of the folding angle for s-and p-polarized light. The absorption enhancement caused by the light-trapping effect was more pronounced for s-polarized light at folding angles smaller than $20^{\circ}$, where s-polarized light has a relatively larger reflectance than p-polarized light. On the other hand, the absorption efficiency for p-polarized light is relatively larger for folding angles larger than $20^{\circ}$, where the smaller reflectance at the interface of the VOSC is more important in obtaining high absorption efficiency.