• Title/Summary/Keyword: %24V_2X%24

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광전도체 $ZnGa_2Se_4$ 박막의 전기적 특성

  • Hong, Gwang-Jun
    • Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
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    • 2010.06a
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    • pp.381-381
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    • 2010
  • From the photocurrent spectrum by illumination of perpendicular light on the c-axis of the ZnGa2Se4singlecrystalthinfilm, wehavefoundthatthevaluesofspinorbitsplitting$\Delta$soandthecrystalfieldsplitting$\Delta$crwere251. 9meVand 183.2me Vat 10K, respectively. FromthephotolwninescencemeasurementontheZnGa2Se4singlecrystalthinfilm,weobservedfreeexcition(EX)existingonlyhighqualitycrystalandneutralboundexiciton(A0,X)havingverystrongpeakintensity.Then,thefull-width-at-half-maximum(FWHM)andbindingenergyofueutralacceptorboundexcitionwerel1meVand24.4meV,respectivity.ByHaynesrule,an activation energy of impurity was 122 meV.

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Characterization and experimental investigation for gamma-ray shielding competence of basalt-doped polyethylene nanocomposites

  • I.A. El-Mesady;F.I. El-Agawany;H. El-Samman;Y.S. Rammah;A. Hussein;R.A. Elsad
    • Nuclear Engineering and Technology
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    • v.56 no.2
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    • pp.477-484
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    • 2024
  • Experimental investigations on gamma - rays attenuation parameters and dielectric spectroscopic properties were done on a polymeric mixture with chemical composition (100-x) polyethylene + x basalt, where x = 0, 1, 3, 5, 10, and 20 wt%. Using the melting blending technique,six nanocomposite polymeric samples were prepared. The linear attenuation coefficient µ of each prepared set of samples was measured using a gamma-ray spectrometer including High Purity Germanium detector (HPGe) at energies 662.5, 1173.24, and 1332.51 keV. Based on the measured values of (µ) and sample density, the other effective shielding parameters were calculated. The values of µ showed an increase with increasing the dopant ratios from 0.0 up to 20.0 wt%. In addition, the µ values decreased with the photon's energy. The µ values were found 0.0847 up to 0.1175 cm-1, 0.0571 up to 0.0855 cm-1, and 0.0543 up to 0.075 cm-1 at 662.5, 1173.24, and 1332.51 keV. for B0 up to B20, respectively. The ATR spectroscopy was done on the prepared samples, and a good evidence of adding the filler to the pure polyethylene (HDPE) was obtained. Besides, an enhancement in dielectric constant by insertion of basalt NPs also recorded and can be attributed to the large dielectric constant of basalt compared to pure HDPE.

An Analysis on Electrical Double Layers at the Silicon Semiconductor Interfaces Using the Zeta Potential (Zeta전위에 의한 Silicon 반도체 계면의 전기이중층 해석)

  • Chun, Jang-Ho
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.24 no.2
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    • pp.242-247
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    • 1987
  • Electrophysical phenomena at the silicon semiconductor-electrolyte solution interfaces were analyzed based on the zeta potential of the electrical double layer and microelectrophoresis. The suspensions were composed of the p or n-type silicon particles suspended in the KCI or pH buffer solutions. The approximate diameter of the prepared and sampled sioicon semiconductor pardticles was 1.5\ulcorner. The sign of the zeta poetntials of the p and n-type silicon particles in the KCl and pH buffer solution was positive. A range of electrophoretic mobilities of the p and n-type silicons in the KCl solutions was 5.5-8.9x10**-4 cm\ulcornerV-sec and 4.2-7.9x10**-4cm\ulcornerV-sec, respectively. The range of zeta potentials corresponding to the electrophoretic mobilities is 70.4-114.0mV nad 53.9-101.2mV, respectively. On the other hand, a range of electrophoretic mobilities of the p and n-type silicons in the pH buffer solutions was 1.1x10**-4-2.2x10**-3cm\ulcornerV-sec and 0-2.1x10**-3cm\ulcornerV-sec, respectively. The range of zeta potentials corresponding to the electrophoretic mobilities is 14.1-281.6mV and 0-268.8mV, respectively. The zeta potentials and electrical double layers of the doped silicon semiconductors are decisively influenced by the positively charged ions in the solutions. The maximum values of the zeta potentials in the KCl solutions appeared at a concentration of about 10-\ulcorner. The isoelectric point of the n-type silicon semiconductors appeared at about a pH 7. The effect of the space charge of the doped silicon semiconductors can be neglected compare with the effect of the surface charge.

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Sterilization of Yakju(Rice Wine) Using a Batch-type High Voltage Pulsed Electric Field System (고전장펄스를 이용한 약주의 회분식 살균)

  • Kim, Su-Yeon;Park, Young-Seo;Mok, Chul-Kyoon
    • Korean Journal of Food Science and Technology
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    • v.31 no.5
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    • pp.1247-1253
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    • 1999
  • Yakju(rice wine) was sterilized with high-voltage pulses of short time on a batch pulsed electric field(PEF) system. The initial microbial counts of Yakju were 7.52 X $10^4\;CFU/mL$ for total aerobes, 2.20 X $10^4\;CFU/mL$ for lactic acid bacteria and 7.08 X $10^4\;CFU/mL$ for yeasts. The pH, acidity and electric conductivity of Yakju were 3.36, 0.462% and 1.24 mS/cm, respectively. Yakju was treated with 2-250 of pulses exponential-wave formed electric pulses under the field strength of 12.5-25 kV/cm. The critical strengths of the electrical field for the sterilization of Yakju were 7.5 kV/cm for total aerobes, 8.5 kV/cm for lactic acid bacteria and 6.5 kV/cm for yeasts. Logarithmic survival rates decreased linearly at low pulse number, but curvilinearly at high pulse number. The PEF sterilization kinetics of Yakju could be analysed by In s = In A-k In (n) and the sterilization rate constant increased with electric field strength and the size of target microorganisms. No changed in pH, acidity, and the growth of microorganisms were found in the PEF treated Yakju during the storage for 6 weeks at both $4^{\circ}C$ And $30^{\circ}C$.

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Growth and Characteristic Infrared Raman Spectra of Potassium Lithium Niobate Single Crystals

  • Youbao Wan;Yoo, Sang-Im
    • Proceedings of the Korea Crystallographic Association Conference
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    • 2002.11a
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    • pp.15-15
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    • 2002
  • Homogeneous and crack-free potassium lithium niobate (K₃Li/sub 2-x/Nb/sub 5+x/O/sub 15/, 0<x<0.5, KLN) single crystals were successfully grown by the Czochralski technique. The KLN single crystals of several different compositions were employed for the investigation of the lattice vibration spectra using infrared Raman spectroscopy. The characteristic Raman spectra of the [NbO/sub 6/]/sup 7-/ octahedral ions were strikingly influenced by the Li ion content. The symmetric stretch vibrational modes V₁, V₂ are broadened, and the symmetric bend vibration mode V/sub 5/ is broadened and even split into three peaks with increasing the Li content, supporting that the bend vibration modes of the [NbO/sub 6/]/sup 7-/ octahedrons are obviously perturbed by Li ions in the C site. Enhanced Raman peak intensities after the post annealing at 900℃ and for 24 h evidenced that a residual stress in as-grown crystals was negligible and only a defect concentration might be reduced.

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Electroless Deposition of ITO Thin Films (무전해침전법에 의한 투명전도박막 제작에 관한 연구)

  • ;邊潤植;李建基
    • Journal of the Korean Institute of Telematics and Electronics
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    • v.24 no.2
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    • pp.238-241
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    • 1987
  • ITO thin film was prepared by the electroless deposition technique. ITO thin film had a high transmittance in the visible region and a high reflectance in the near infrared region. The energy gap of the thn film (Sn/Im=0.1) was 4.05 eV, the carrier concentration was 2x10**21 cm**-3, and the electric resistivity was 1.5x10**-3 ohm-cm. We confirmed that ITO thin film was a degenerated n-type semiconductor.

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Active Effect of Antivoagulant Effects in chaenomelis Fructus Water Extract (모과 추출물의 항응혈 활성)

  • Yoo, Ji-Hyun;Han, Sin-Hee;Kil, Gi-Jung
    • The Korea Journal of Herbology
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    • v.24 no.2
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    • pp.7-11
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    • 2009
  • Objectives : This research was investigated anticoagulant effect of the Chaenomelis Fructus extract. Methods : To examine an active effect of anticoagulation in Chaenomelis Fructus extract, the study measured Prothrombin time(PT) and activated partial thromboplastin time (APTT) of human plasma in vitro and measured bleeding time and arterio-venous shunt model in rats in vivo. Results : Bleeding time of Chaenomelis Fructus extract in vivo had a significant increase as about 1.6 times and thrombus weight of Chaenomelis Fructus extract had a significant reduction of thrombus weight as 50%. Chaenomelis Fructus extract represented an effect of anticoagulation by operating on extrinsic pathway factor II, V, VII, X and intrinsic pathway factor VIII, IX, X, XI, XII in the coagulation system. Conclusions : Considering the above mentioned results, it is judged that a Chaenomelis Fructus extract has a control effect of thrombus creation.

Design of 2-Ch DC-DC Converter with Wide-Input Voltage Range of 2.9V~5.6 V for Wearable AMOLED Display (2.9V~5.6V의 넓은 입력 전압 범위를 가지는 웨어러블 AMOLED용 2-채널 DC-DC 변환기 설계)

  • Lee, Hui-Jin;Kim, Hak-Yun;Choi, Ho-Yong
    • Journal of IKEEE
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    • v.24 no.3
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    • pp.859-866
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    • 2020
  • This paper proposes a 2-ch DC-DC converter with a wide-input voltage range from 2.9V~5.6V for wearable AMOLED displays. For positive voltage VPOS, a boost converter is designed using an over-charged voltage permissible circuit (OPC) which generates a normal output voltage even if over-input voltage is applied, and a SPWM-PWM dual mode with 3-segmented power transistors to improve efficiency at light load. For negative voltage VNEG, a 0.5x regulated inverting charge pump is designed to increase power efficiency. The proposed DC-DC converter was designed using a 0.18-㎛ BCDMOS process. Simulation results show that the proposed DC-DC converter generates VPOS voltages of 4.6 V and VNEG voltage of -0.6V~-2.3V for input voltage of 2.9V to 5.6V. In addition, it has power efficiency of 49%~92%, output ripple voltage has less than 20 mV for load current range of 1 mA~70 mA.

Planar Imaging of Temperature and Concentration of a Laminar Nonpremixed $H_2$/$N_2$flame Using a Tunable KrF Excimer Laser (파장 가변형 KrF 에시머 레이저를 이용한 층류 비예혼합 수소 화염에서의 2차원적 온도 및 농도 계측)

  • Kim, Gun-Hong;Jin, Seong-Ho;Kim, Yong-Mo;Park, Gyeong-Seok;Kim, Se-Won;Kim, Gyeong-Su
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.24 no.12
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    • pp.1580-1587
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    • 2000
  • Rayleigh scattering and laser induced predissociative fluorescence are employed for capturing two-dimensional images of temperature and species concentration in a laminar nonpremixed flame of a diluted hydrogen jet. Rayleigh scattering cross-sections are experimentally obtained ar 248nm. Dispersed LIPF spectra of OH and O$_2$ are also measured in a flame in order to confirm the excitation of single vibronic state of OH and O$_2$ .OH and O$_2$ are excited on the P$_1$(8) line of the A $^2\Sigma ^+(v^`=3) - X^2\pi (V^"=0)$ band and R(17) line of the Schumann-Runge band B $^3\Sigma _u^-(v^`=0) - X ^3\Sigma _g^-(v^"=6)$, respectively. Fluorescence spectra of OH and Hot O$_2$ are captured and two-dimensional images of the hydrogen flame field are successfully visualized.

Study on Electrical Characteristics of Hafnium Silicate Films with Low Temperature O2 Annealing (저온 Osub2 어닐링 공정을 통한 HfSixOy의 전기적 특성 개선)

  • Lee, Jung-Chan;Kim, Kwang-Sook;Jeong, Seok-Won;Roh, Yong-Han
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.24 no.5
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    • pp.370-373
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    • 2011
  • We investigated the effects of low temperature ($500^{\circ}C$) $O_2$ annealing on the characteristics of hafnium silicate ($HfSi_xO_y$) films deposited on a Si substrate by atomic layer deposition (ALD). We found that the post deposition annealing under oxidizing ambient causes the oxidation of residual Hf metal components, resulting in the improvement of electrical characteristics such as flat band voltage shift (${\Delta}V_{fb}$) by hysteresis without oxide capacitance reduction. We suggest that post deposition annealing under oxidizing ambient is necessary to improve the electrical characteristics of $HfSi_xO_y$ films deposited by ALD.