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검색결과 291건 처리시간 0.028초

광전도체 $ZnGa_2Se_4$ 박막의 전기적 특성

  • 홍광준
    • 한국전기전자재료학회:학술대회논문집
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    • 한국전기전자재료학회 2010년도 하계학술대회 논문집
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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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    • 제56권2호
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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.

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

  • Chun, Jang-Ho
    • 대한전자공학회논문지
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    • 제24권2호
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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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고전장펄스를 이용한 약주의 회분식 살균 (Sterilization of Yakju(Rice Wine) Using a Batch-type High Voltage Pulsed Electric Field System)

  • 김수연;박영서;목철균
    • 한국식품과학회지
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    • 제31권5호
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    • pp.1247-1253
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    • 1999
  • 고전장 펄스가 전통 약주의 살균에 미치는 영향을 살펴보기 위하여 비살균 약주를 사용하여 고전장 펄스를 회분식 처리를 하여 다음과 같은 결과를 얻었다. 약주의 초기미생물수는 세균 7.52 X $10^4\;CFU/mL$, 젖산균 2.20 X $10^4\;CFU/mL$, 효모 7.08 X $10^4\;CFU/mL$이었다. 약주의 PEF 처리전 pH는 3.36, 산도는 0.462%, 전기전도도는 1.24 mS/cm이었다. 약주를 고전장 펄스처리하는데 사용한 전기장의 세기는 12.5-25 kv/cm로 하였으며 exponential-wave형태의 펄스를 전기장의 세기에 따라 펄스수를 달리하여 처리하였다. 약주의 살균을 위한 최소임계전기장의 세기는 총균의 경우 7.5 kV/cm, 젖산균의 경우 8.5 kV/cm, 효모의 경우 6.5 kV/cm 이었다. 약주를 PEF 처리한 경우 전기장세기와 펄스수가 증가할수록 미생물의 살균효과가 증가하였다. PEF처리에 의한 약주 미생물의 사멸기작은 In s = In A-k In(n)에 적용되었으며 사멸속도상수는 전기장세기에 따라 증가하였고 미생물 종류별로는 효모>일반세균>젖산균 순으로 낮아졌다. PEF 처리하여 저장하였을 경우 PEF처리구는 pH의 변화와 적정산도의 변화가 없었으며 미생물의 경우 PEF처리한 시료는 $4^{\circ}C$$30^{\circ}C$ 저장중 미생물의 생육을 보이지 많아 PEF처리에 의한 저장성 향상이 확인되었다.

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

  • Youbao Wan;Yoo, Sang-Im
    • 한국결정학회:학술대회논문집
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    • 한국결정학회 2002년도 정기총회 및 추계학술연구발표회
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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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무전해침전법에 의한 투명전도박막 제작에 관한 연구 (Electroless Deposition of ITO Thin Films)

  • 박상희
    • 대한전자공학회논문지
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    • 제24권2호
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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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모과 추출물의 항응혈 활성 (Active Effect of Antivoagulant Effects in chaenomelis Fructus Water Extract)

  • 유지현;한신희;길기정
    • 대한본초학회지
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    • 제24권2호
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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.

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

  • 이희진;김학윤;최호용
    • 전기전자학회논문지
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    • 제24권3호
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    • pp.859-866
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    • 2020
  • 본 논문에서는 2.9 V ~ 5.6V의 넓은 입력 전압 범위를 가지는 웨어러블 AMOLED용 2-채널 DC-DC 변환기를 설계한다. 양전압 VPOS는 과도한 입력전압이 인가된다 하더라도 정상 출력 전압을 생성되는 OPC를 내장하고, 경부하 효율을 제고하기 위한 SPWM-PWM 듀얼모드 및 파워 트랜지스터 3-분할을 적용한 부스트 변환기로 설계한다. 음전압 VNEG는 전력 효율을 높이기 위해 0.5x 인버팅 차지펌프를 이용해 설계한다. 제안된 DC-DC 변환기는 0.18-㎛ BCDMOS 공정으로 설계하였다. DC-DC 변환기는 2.9V~5.6V의 입력 전압에 대해 4.6V의VPOS와 -0.6V~-2.3V의 VNEG 전압을 생성한다. 또한 1mA~70mA 부하전류에서 49%~92%의 전력효율과 최대 20mV의 출력 리플을 가졌다.

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

  • 김군홍;진성호;김용모;박경석;김세원;김경수
    • 대한기계학회논문집B
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    • 제24권12호
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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.

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

  • 이정찬;김광숙;정석원;노용한
    • 한국전기전자재료학회논문지
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    • 제24권5호
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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.