• 한국전기전자재료학회논문지
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• 제17권8호
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• pp.823-829
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• 2004

In this paper, non-self-aligned SiGe HBTs with ${f}_\tau$ and${f}_max $above 50 GHz have been fabricated using an RPCVD(Reduced Pressure Chemical Vapor Deposition) system for wireless applications. In the proposed structure, in-situ boron doped selective epitaxial growth(BDSEG) and TiSi$_2$ were used for the base electrode to reduce base resistance and in-situ phosphorus doped polysilicon was used for the emitter electrode to reduce emitter resistance. SiGe base profiles and collector design methodology to increase ${f}_\tau$ and${f}_max $ are discussed in detail. Two SiGe HBTs with the collector-emitter breakdown voltages ${BV}_CEO$ of 3 V and 6 V were fabricated using SIC(selective ion-implanted collector) implantation. Fabricated SiGe HBTs have a current gain of 265 ∼ 285 and Early voltage of 102 ∼ 120 V, respectively. For the $1\times{8}_\mu{m}^2$ emitter, a SiGe HBT with ${BV}_CEO$= 6 V shows a cut-off frequency, ${f}_\tau$of 24.3 GHz and a maximum oscillation frequency, ${f}_max $of 47.6 GHz at $I_c$of 3.7 mA and$V_CE$ of 4 V. A SiGe HBT with ${BV}_CEO$ = 3 V shows ${f}_\tau$of 50.8 GHz and ${f}_max $ of 52.2 GHz at $I_c$ of 14.7 mA and $V_CE$ of 2 V.

• 한국생산제조학회지
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• 제8권4호
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• pp.52-60
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• 1999

In this study the effect of roundness error with respect to the cutting conditions using the external cylindrical work piece by end mill cutting in a machining center was studied. the end mill used in this study is HSS coated with Ti-N which is of Ø 12-4 flutes. The material of workpiece is SM20C and cutting oil is used as a cooling flued The cutting experiments were carried out for the several cutting conditions(depth of cut height of end mill feed rate revolution per minute and cutting direction) and their roundness effects were compared using the least squares circle measuring method. The experimental results are summarized as follows : 1) The cutting depth is dominant for the roundness of a cylindrical work piece and the cutting speed must be determined precisely when the cutting depth is large 2) When the cutting direction in circular manufacturing is the same with the spindle rotation i.e up-cutting condition the surface roundness is also improved.

• 대한전기학회:학술대회논문집
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• 대한전기학회 1995년도 하계학술대회 논문집 C
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• pp.1290-1292
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• 1995

A cylindrical-post magnetron sputtering system was designed for pipe inner coating. The discharge condition was depended on the gas pressure, magnetic field and pipe diameter. At given discharge current, discharge voltage increased a little with pipe diameter. The electron temperature and floating potential increased with magnetic field. The impact ion energy on the pipe increased with bias voltage. The TiN thin-film of $2{\mu}m$ thickness was formed by cylindrical-post magnetron sputtering system under the conditions of the pressure of 5mTorr, the applied voltage of 700V, the discharge current of 500mA, the magnetic field of 300G, and the bias voltage of -100V.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2004년도 Asia Display / IMID 04
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• pp.1091-1094
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• 2004

High-luminous efficiency full-color emissions in photoluminescence (PL) were obtained in $GdVO_4$ phosphor thin films co-doped with various amounts of Eu, Er and/or Tm and postannealed at approximately 1000$^{\circ}C$. The $GdVO_4$:Eu,Er,Tm phosphor thin films were deposited on thick $BaTiO_3$ ceramic sheets by r.f. magnetron sputtering using powder targets and postannealed in an air atmosphere. The rare earth (RE) content (RE/(Gd+V+RE) atomic ratio) in the oxide phosphor thin films was varied in the range from 0.1 to 2 at.%. It was found that the excitation of $GdVO_4$:Eu.Er,Tm thin films is attributed to band-to-band transition. A white PL emission was obtained in a $GdVO_4$:Eu,Er,Tm thin film with Eu, Er and Tm contents of 0.2, 0.7 and 1 at.%, respectively: CIE chromaticity color coordinates. (X=0.352 and Y=0.351). In addition, a white emission was obtained in a thin-film electroluminescent (TFEL) device made with this thin film.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2002년도 춘계학술대회 논문집
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• pp.387-392
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• 2002

This paper presents a new scheme of neural network controller to improve the robustuous of robot manipulator using digital signal processors. Digital signal processors, DSPs, are micro-processors that are particularly developed for fast numerical computations involving sums and products of variables. Digital version of most advanced control algorithms can be defined as sums and products of measured variables, thus it can be programmed and executed through DSPs. In addition, DSPs are as fast in computation as most 32-bit micro-processors and yet at a fraction of their prices. These features make DSPs a viable computational tool in digital implementation of sophisticated controllers. During past decade it was proposed the well-established theorys for the adaptive control of linear systems, but there exists relatively little general theory for the adaptive control of nonlinear systems. Perforating of the proposed controller is illustrated. This paper describes a new approach to the design of adaptive controller and implementation of real-time control for assembling robotic manipulator using digital signal processor. Digital signal processors used in implementing real time adaptive control algorithm are TMS320C50 series made in TI'Co..

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2001년도 추계학술대회(한국공작기계학회)
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• pp.134-139
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• 2001

This paper presents a new scheme of neural network controller to improve the robustuous of robot manipulator using digital signal processors. Digital signal processors, DSPs, are micro-processors that are particularly developed for fast numerical computations involving sums and products of variables. Digital version of most advanced control algorithms can be defined as sums and products of measured variables, thus it can be programmed and executed through DSPs. In addition, DSPs are as fast in computation as most 32-bit micro-processors and yet at a fraction of their prices. These features make DSPs a viable computational tool in digital implementation of sophisticated controllers. During past decade it was proposed the well-established theorys for the adaptive control of linear systems, but there exists relatively little general theory for the adaptive control of nonlinear systems. Perforating of the proposed controller is illustrated. This paper describes a new approach to the design of adaptive controller and implementation of real-time control for assembling robotic manipulator using digital signal processor. Digital signal processors used in implementing real time adaptive control algorithm are TMS320C50 series made in TI'Co..

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.73-74
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• 2006

Ferroelectric thin films have been widely investigated for future nonvolatile memory application. We fabricated the BLT ($(Bi,La)_4Ti_3O_{12}$) films on Si using a STA ($SrTa_2O_6$) buffer layer BLT and STA film were prepared by sol-gel method. Measurement data by XRD and AFM, showed that BLT film and STA films were well crystallized and a good surface morphology. From C-V measurement reward that the Au/BLT/STA/Si structure showed a clockwise hysteresis loop with a memory window of 1.5 V for the bias voltage sweep of ${\pm}5$ V. From results, the Au/BLT/STA/Si structure is useful for FeFETs.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2003년도 하계학술대회 논문집 Vol.4 No.2
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• pp.719-722
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• 2003

Ferroelectric $Pb(Zr_{1-x}Ti_x)O_3$ (PZT) films were deposited on (001) MgO single crystals using sol-gel method. Structural properties and surface morphologies of PZT films were investigated using an X-ray diffractometer and a scanning electron microscopy, respectively. The dielectric properties of PZT films were investigated with the dc bias field using interdigitated capacitors (IDC) which were fabricated on PZT films using a thick metal layer by photolithography and dry etching process. The small signal dielectric properties of PZT films were calculated by a modified conformal mapping method with low and high frequency data, such as capacitance measured by an impedance gain/phase analyzer at 100 kHz and reflection coefficient (S-parameter) measured by a HP 8510C vector network analyzer at 1 -20 GHz. The IDC on PZT films exhibited about 67% of capacitance change with an electric field of 135 kV/cm at 10 GHz. These PZT thin films can be applied to tunable microwave devices such as phase shifters, tunable resonators and tunable filters.

• 전기학회논문지
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• 제65권4호
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• pp.617-621
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• 2016

In addition to the energy storage facilities based on high power technologies, Electric double layer capacitors(EDLC) are today's candidate for power quality stabilization. However, its low energy density is often inhibiting factor for application of electric power industry. Hybrid supercapacitor is an promising energy storage device that positioned between conventional EDLC and Li-ion battery. This paper describes the preparation and characteristics of a hybrid supercapacitor and module for power quality stabilization. A cylindrical 3200F hybrid supercapacitor ($60{\times}74.5mm$) was assembled by using the $Li_4Ti_5O_{12}$ electrode as an anode and activated carbon as a cathode. It shows 2.5 times higher energy density than conventional EDLC with the same volume. In order to determine the characteristics of the hybrid supercapacitor Module for uninterruptible power supply (UPS), hybrid supercapacitor cells were connected in series with active balancing circuit. At even the high current density of 14A(10C), Module prepared by 18 cells showed the capacitance of 170F at 30~50V, suggesting the applicability for UPS.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1997년도 춘계학술대회 논문집
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• pp.751-755
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• 1997

This paper presents a new scheme of neural network controller to improve to improve the robustuous of robot manipulator using digital signal processors. Digital processors, DSPs, are micro-processors that are particularly developed for fast numerical computations involving sums and products of variables. Digital version of most advanced control algorithms can be defined as sums and producrs of measured variables, thus it can be programmed and executed through DSPs. In addition, DSPs are as fist in computation as most 32-bit micro-processors and yet at a fraction of their prices. These features make DSPs a viable computational tool in digital implementation of sophisticated controllers. During past decade it was proposed the well-established theorys for the adaptive control of linear systems, but there exits relativly little gensral theoral for the adaptive control of nonlinear systems. Perforating of the proposed controller is illustrated. This paper describes a new approach to the design of adaptive controller and implementation of real-time control for assembling robotic manipulator using digital signal processor. Digital signal processors used in implementing real time adaptive control algorithm are TMS320C50 series made in TI'Co..