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991.
Jeong-Ryeol Kim Geun-Kyu Choi Dong Kyun Yim Jong-Sung Park Kug Sun Hong 《Journal of Electroceramics》2006,17(1):65-69
Glasses in the ZnO-B2O3-MO3(M = W, Mo) ternary were examined as potential replacements to PbO-B2O3-SiO2-ZnO glass frits with the low firing temperature (500–600∘C) for the dielectric layer of a plasma display panels (PDPs). Glasses were melted in air at 950–1150∘C in a narrow region of the ternary using standard reagent grade materials. The glasses were evaluated for glass transition
temperature (T
g
), softening temperature (T
d
), the coefficient of thermal expansion (CTE), dielectric constant (ε
r
), and optical property. The glass transition temperature of the glasses varied between 470 and 560∘C. The coefficient of thermal expansion and the dielectric constant of the glasses were in the range of 5–8 × 10− 6/∘C and 8–10, respectively. The addition of MO3to ZnO-B2O3binary could induce the expansion of glass forming region, the reduction of T
g
and the increase in the CTE and the dielectric constant of the glasses. Also, the effect of the addition of MO3to ZnO-B2O3binary on the transmittance in the visible-light region (350–700 nm) was investigated. 相似文献
992.
993.
A 1.2 V 83 dB DR single‐ended input SC ΔΣ modulator including a large‐swing analog buffer for portable ECG applications 下载免费PDF全文
Quanzhen Duan Youngjae Jung Danbi Choi Jeongjin Roh Jongpal Kim 《International Journal of Circuit Theory and Applications》2016,44(12):2164-2173
This study proposes a subsystem consisting of an analog buffer and a single‐ended input to a fully differential ΔΣ modulator to obtain low‐power consumption for portable electrocardiogram applications. With the proposed subsystem, the need for an inverting amplifier is avoided, and low‐power consumption is achieved. The ΔΣ modulator with a second order, 1 bit, and cascade of integrators feedforward structure consumes a low power, in which an inverting and a non‐inverting path implement a single‐ended input to fully‐differential signals. A double sampling technique is proposed for a digital‐to‐analog converter feedback circuit to reduce the effect of the reference voltage, reduce the amplifier requirements, and obtain low‐power consumption. Input‐bias and output‐bias transistors working in the weak‐inversion region are implemented to obtain an extremely large swing for the analog buffer. At a supply voltage of 1.2 V, signal bandwidth of 250 Hz, and sampling frequency of 128 kHz, the measurement results show that the modulator with a buffer achieves a 77 dB peak signal‐to‐noise‐distortion ratio, an effective‐number‐of‐bits of 12.5 bits, an 83 dB dynamic range, and a figure‐of‐merit of 156 dB. The total chip size is approximately 0.28 mm2 with a standard 0.13 µm Complementary Metal‐Oxide‐Silicon (CMOS) process. Copyright © 2016 John Wiley & Sons, Ltd. 相似文献
994.
Kin Foong Chan Choi B. Vargas G. Hammer D.X. Sorg B. Pfefer T.J. Teichman J.M.H. Welch A.J. Jansen E.D. 《IEEE journal of selected topics in quantum electronics》2001,7(6):1022-1033
Infrared laser ablation of urinary calculi was investigated as a function of wavelength to determine the relation of ablation threshold fluences, ablation depths, and optical absorption. A simple photothermal ablation model was employed to examine this relationship. Human urinary calculi composed of >95% uric acid, >95% cystine, >95% calcium oxalate monohydrate (COM), and >90% magnesium ammonium phosphate hexahydrate (MAPH) were used. Various wavelengths between 2.1 and 6.5 μm were selected to perform threshold fluence and ablation depth measurements. The laser source for this study was the tunable pulsed infrared free electron laser (FEL) at Vanderbilt University. Experimental results indicated a correlation of threshold fluence and ablation depth to the optical absorption properties of the calculi. When calculus optical absorption increased, the threshold fluences decreased. Although the ablation depths increased with calculus optical absorption, results indicated that in certain calculi the ablation depth was affected by optical attenuation through the ablation plume. These observations were in agreement with the photothermal ablation model, but fractures in striated calculi at higher optical absorptions indicated the contribution of a photomechanical mechanism 相似文献
995.
Woo-Chang Choi Zhixin Wan Ji-Hoon Ahn Doo-In Kim Seung-Yong Shin Kyung-Il Moon Jin-Seong Park Jung-Dae Kwon Se-Hun Kwon 《Journal of Electroceramics》2014,32(2-3):240-245
Ru-AlN thin films were suggested as a novel multifunctional heating resistor film for non-passivated type thermal inkjet printer devices. Ru-AlN thin films were prepared by plasma-enhanced atomic layer deposition in order to intermix Ru and AlN precisely. When the Ru intermixing ratios were optimized, Ru-AlN films showed a favorable electrical resistivity (from 490.9 to 75.3 μΩcm) and minimized temperature coefficient of resistance (TCR) values (from 335 to 360 ppm/K). Moreover, the Ru-AlN films showed a strong oxidation resistant as compared with commercially used TaN0.8 films because the prepared Ru-AlN thin films had a typical nanocomposite structure. By applying electrical pulses to the heater device using Ru-AlN thin films for a Joule heating, a reliable operation was also proven. 相似文献
996.
Mun-Seok Choi Sung-Hoon Kim Young-Hyeok Kim Ill Won Kim Soon-Jong Jeong Jae-Sung Song Jae-Shin Lee 《Journal of Electroceramics》2008,20(3-4):225-229
Ag–ceramic composite materials were investigated as low-cost internal electrodes for low firing piezoelectric multilayer ceramic
actuators (MLCA). Ag–ceramic pastes were prepared by adding Pb(Mg1/3Nb2/3)O3–Pb(Zr0.475,Ti0.525)O3 (PMNZT) ceramic powders to a commercial Ag paste in the range of 0 to 50 wt.%. PMNZT/Ag–PMNZT multilayered laminates were
fabricated using tape casting and subsequently cofired at 925°C for 10 h. The addition of PMNZT into Ag electrode decreased
the thermal shrinkage mismatch between the composite layers, which led to improve mass producibility of MLCA through reducing
delamination probability during cofiring process. 相似文献
997.
Electrical conductivity of the Al-stabilized La<Subscript>2/3</Subscript>TiO<Subscript>3</Subscript>
A-site deficient lanthanum titanate (La2/3TiO3) materials with perovskite structure are attractive due to their electrical applications such as ion conductors and dielectrics.
However, its stability at room temperature in air is obtained only if Na or Li etc. is incorporated into La site or Al into
Ti site. In this study, the electrical conductivities of La0.683(Ti0.95Al0.05)O3 have been measured in oxygen partial pressure (Po2) between 1 and 10−18 atm at 1000~1400°C. The electrical conductivity exhibited −1/4, −1/6 and −1/5 dependence (log σ ∝ log , n = −1/4, −1/6, −1/5) depending upon temperature and Po2. The defect model explaining the observation was proposed and discussed. The chemical diffusion coefficient was estimated
from the electrical conductivity relaxation. 相似文献
998.
Pelusi M.D. Ta'eed V.G. Libin Fu Magi E. Lamont M.R.E. Madden S. Duk-Yong Choi Bulla D.A.P. Luther-Davies B. Eggleton B.J. 《IEEE journal of selected topics in quantum electronics》2008,14(3):529-539
Ultrahigh nonlinear tapered fiber and planar rib Chalcogenide waveguides have been developed to enable highspeed all-optical signal processing in compact, low-loss optical devices through the use of four-wave mixing (FWM) and cross-phase modulation (XPM) via the ultra fast Kerr effect. Tapering a commercial As2Se3 fiber is shown to reduce its effective core area and enhance the Kerr nonlinearity thereby enabling XPM wavelength conversion of a 40 Gb/s signal in a shorter 16-cm length device that allows a broader wavelength tuning range due to its smaller net chromatic dispersion. Progress toward photonic chip-scale devices is shown by fabricating As2S3 planar rib waveguides exhibiting nonlinearity up to 2080 W-1ldr km-1 and losses as low as 0.05 dB/cm. The material's high refractive index, ensuring more robust confinement of the optical mode, permits a more compact serpentine-shaped rib waveguide of 22.5 cm length on a 7-cm- size chip, which is successfully applied to broadband wavelength conversion of 40-80 Gb/s signals by XPM. A shorter 5-cm length planar waveguide proves most effective for all-optical time-division demultiplexing of a 160 Gb/s signal by FWM and analysis shows its length is near optimum for maximizing FWM in consideration of its dispersion and loss. 相似文献
999.
Fazli Akram Rizwan Ahmed Malik Salman Ali Khan Ali Hussain Soonil Lee Myang-Hwan Lee Choi Hai In Tae-Kwon Song Won-Jeong Kim Yeon Soo Sung Myong-Ho Kim 《Journal of Electroceramics》2018,41(1-4):93-98
In the present work, composition dependent crystal structure, ferroelectric, piezoelectric, and temperature dependent dielectric properties of the BiGaO3-modified (1–x)(0.65Bi1.05FeO3–0.35BaTiO3) (BFBT35–xBG, where x?=?0.00–0.03) lead-free ceramics were systematically investigated by solid-state reaction method, followed by water quenching process. The substitution of BG successfully diffuses into the lattice of the BFBT ceramics, without changing the pseudo-cubic structure of the samples. The scanning electron microscopy (SEM) results revealed that the average grain size was increased with BG-content in BFBT system. The BFBT–xBG ceramics showed a maximum in permittivity (?max) at temperatures (Tmax) above 500 °C in the compositional range of 0.00?≤?x?≤?0.03. The electro-strain is measured to be 0.125% (d*33 ~ 250 pm/V) under unipolar fields (5 kV/mm) for BFBT–0.01BG ceramics. The same composition (x?=?0.01), large static piezoelectric constant (d33 ~ 165 pC/N) and electromechanical coupling factor (kp ~ 25%) were obtained. The above investigated characterizations suggests that BFBT–BG material is favorable for piezoelectric and high temperature applications. 相似文献
1000.
Hun Park Dae-Jin Yang Ho-Gi Kim Seong-Je Cho Su-Chul Yang Hyunjung Lee Won-Youl Choi 《Journal of Electroceramics》2009,23(2-4):146-149
Dye-sensitized solar cells (DSCs) are more spotlighted than conventional photovoltaic devices due to their relatively low cost, easy fabrication and high efficiency. However, there are limitations to increase the conversion efficiency of DSCs. The limiting factors are the quantity of dye adsorption and charge recombination between TiO2 electrode and electrolyte. Coating other materials such as high energy band gap insulators or semiconductors on the TiO2 electrode enhances dye adsorption and reduces charge recombination. We fabricated DSCs based on bare TiO2 nanotube arrays and 0.02 and 0.04 M MgO coated TiO2 nanotube arrays. MgO layer increased the photovoltage and photocurrent. The overall conversion efficiency of DSCs using 0.02 M MgO coated TiO2 nanotubes was 1.61%. MgO formed insulating layers between TiO2 nanotube array electrode and electrolyte. Charge recombination was inhibited at the interfaces of TiO2 nanotube array electrode and electrolyte by MgO insulating layers. MgO coating also improved dye adsorption because iso-electric point (IEP) of MgO was larger than TiO2. When the IEP of coating material is larger than TiO2, the chemical attraction between the electrode surface and Ru-based dye molecule is increased. 相似文献