• Title/Summary/Keyword: J-V curve

Search Result 124, Processing Time 0.026 seconds

A Measurement and Analysis of Thermoluminescence Spectra of LaAlO3 (LaAlO3에 대한 열자극발광 스펙트럼의 광학적 분석)

  • Lee, J.I.;Moon, J.H.;Kim, D.H.
    • Journal of Korean Ophthalmic Optics Society
    • /
    • v.4 no.2
    • /
    • pp.141-146
    • /
    • 1999
  • We measured and analyzed thermoluminescence spectra of $LaAlO_3$, single crystal by 3 dimensional data for temperature, wavelength and luminescence intensity. $LaAlO_3$, has used as the substrates of YBCO(superconductor) or semiconductors. We could determined the energy of recombination center, that is impossible through analysis of glow curve data. We could obtained the energy through analysis of the spectrum data at peak temperature by Franck-Condon model. The total glow curve was deconvoluted to three glow curves by curve fitting method. The activation energies were 0.54eV, 0.91eV and 1.02eV respectively. The energies of recombination centers were determined with 2.04eV and 2.75eV from the analysis of luminescence intensity data for wavelength.

  • PDF

An Analysis of Near-infrared Light Curves of δ Scuti Variable BO Lyn (δ Scuti형 변광성 BO Lyn의 근적외선 광도곡선 분석)

  • Lim, Ji-Hye;Sohn, Jungjoo
    • Journal of the Korean earth science society
    • /
    • v.37 no.7
    • /
    • pp.389-397
    • /
    • 2016
  • In order to investigate the light curve difference in visual and infrared wavelength of ${\delta}$ Scuti variable Bo Lyn, observations were performed using BOAO 1.8m reflecting telescope and an infrared detector, KASINICS, with J, H, and Ks filters. Infrared light curves of total 7 nights were obtained between March and April in 2011, and those were compared to the V-filter light curve to examine the differences in period, time of maximum light, amplitude, and shape. From the periodic analysis of infrared light curve, a single frequency of $f_1=10.712cycle/day$, $P=0.09335{\pm}0.00002days$ was obtained, and there was no difference in the period along different wavelengths. In the infrared light curve, a frequency of $2f_1$ was detected. This frequency well explains the asymmetric shape of light curve, one of the characteristics of high-amplitude ${\delta}$ Scuti variables. We compared the locations of the measured infrared maxima and the predicted maxima of V-filter, finding that the times of maxima were delayed about 0.3 phase at infrared wavelengths. Amplitude ratios were adopted to be ${\Delta}J/{\Delta}V=0.328$, ${\Delta}H/{\Delta}V=0.216$, and ${\Delta}Ks/{\Delta}V=0.211$, with the range of variation being smaller at longer wavelengths. It seems that the differences in the times of maxima and amplitude occurred because the changes in brightness of a pulsating variable star are mainly caused by the change in temperature.

Photometry of the long-period eclipsing polar V1309 Ori

  • Kim, Y.;K. Reinsch;Y. B. Jeon
    • Bulletin of the Korean Space Science Society
    • /
    • 2003.10a
    • /
    • pp.24-24
    • /
    • 2003
  • We present preliminary results about the quasi-simultaneous near-infrared light curves of the long-period eclipsing polar V1309 Ori in the J, H, K', and K bands with almost complete orbital phase coverage using the CFHT-IR camera. The optical light curve in the V and R bands, obtained by 1.8m Telescope at BOAO, will be also presented. The shape and the amplitude of the orbital light curve change significantly from optical to near-infrared wavelengths.

  • PDF

Analysis of the Current-voltage Curves of a Cu(In,Ga)Se2 Thin-film Solar Cell Measured at Different Irradiation Conditions

  • Lee, Kyu-Seok;Chung, Yong-Duck;Park, Nae-Man;Cho, Dae-Hyung;Kim, Kyung-Hyun;Kim, Je-Ha;Kim, Seong-Jun;Kim, Yeong-Ho;Noh, Sam-Kyu
    • Journal of the Optical Society of Korea
    • /
    • v.14 no.4
    • /
    • pp.321-325
    • /
    • 2010
  • We analyze the current density - voltage (J - V) curve of a Cu(In,Ga)$Se_2$ (CIGS) thin-film solar cell measured at different irradiation power densities. For the solar-cell sample investigated in this study, the fill factor and power conversion efficiency decreased as the irradiation power density (IPD) increased in the range of 2 to 5 sun. Characteristic parameters of solar cell including the series resistance ($r_s$), the shunt resistance ($r_{sh}$), the photocurrent density ($J_L$), the saturation current density ($J_s$) of an ideal diode, and the coefficient ($C_s$) of the diode current due to electron-hole recombination via ionized traps at the p-n interface are determined from a theoretical fit to the experimental data of the J - V curve using a two-diode model. As IPD increased, both $r_s$ and $r_{sh}$ decreased, but $C_s$ increased.

Low Reverse Saturation Current Density of Amorphous Silicon Solar Cell Due to Reduced Thickness of Active Layer

  • Iftiquar, S M;Yi, Junsin
    • Journal of Electrical Engineering and Technology
    • /
    • v.11 no.4
    • /
    • pp.939-942
    • /
    • 2016
  • One of the most important characteristic curves of a solar cell is its current density-voltage (J-V) curve under AM1.5G insolation. Solar cell can be considered as a semiconductor diode, so a diode equivalent model was used to estimate its parameters from the J-V curve by numerical simulation. Active layer plays an important role in operation of a solar cell. We investigated the effect thicknesses and defect densities (Nd) of the active layer on the J-V curve. When the active layer thickness was varied (for Nd = 8×1017 cm-3) from 800 nm to 100 nm, the reverse saturation current density (Jo) changed from 3.56×10-5 A/cm2 to 9.62×10-11 A/cm2 and its ideality factor (n) changed from 5.28 to 2.02. For a reduced defect density (Nd = 4×1015 cm-3), the n remained within 1.45≤n≤1.92 for the same thickness range. A small increase in shunt resistance and almost no change in series resistance were observed in these cells. The low reverse saturation current density (Jo = 9.62×10-11 A/cm2) and diode ideality factor (n = 2.02 or 1.45) were observed for amorphous silicon based solar cell with 100 nm thick active layer.

A Study on the Fabrication of Plasma Display Panel and It's Characteristics (플라즈마 디스플레이 판넬의 제작 및 특성 연구)

  • Kim, J.S.;Choi, K.C.;Shin, B.J.;Whang, K.W.
    • Proceedings of the KIEE Conference
    • /
    • 1990.11a
    • /
    • pp.157-160
    • /
    • 1990
  • A dot matrix type DC Plasma Display Panel was fabricated and it's characteristics was investigated. Paschen curve and I-V curve of various gas mixture was given. Optimal gas mixing ratio, pressure and operating point was determined. The priming effect was observed and discharge delay time was measured with varing applied voltage, priming current, priming distance, duty ratio.

  • PDF

LOW RANK ORTHOGONAL BUNDLES AND QUADRIC FIBRATIONS

  • Insong Choe ;George H. Hitching
    • Journal of the Korean Mathematical Society
    • /
    • v.60 no.6
    • /
    • pp.1137-1169
    • /
    • 2023
  • Let C be a curve and V → C an orthogonal vector bundle of rank r. For r ≤ 6, the structure of V can be described using tensor, symmetric and exterior products of bundles of lower rank, essentially due to the existence of exceptional isomorphisms between Spin(r, ℂ) and other groups for these r. We analyze these structures in detail, and in particular use them to describe moduli spaces of orthogonal bundles. Furthermore, the locus of isotropic vectors in V defines a quadric subfibration QV ⊂ ℙV . Using familiar results on quadrics of low dimension, we exhibit isomorphisms between isotropic Quot schemes of V and certain ordinary Quot schemes of line subbundles. In particular, for r ≤ 6 this gives a method for enumerating the isotropic subbundles of maximal degree of a general V , when there are finitely many.

The Measurement and Analysis of LiF:Mg, Cu, Na, Si TL Material by Thermoluminescence Spectrum (LiF:Mg, Cu, Na, Si TL 물질의 열자극발광스펙트럼 측정 및 분석)

  • Lee, J.I.;Moon, J.H.;Kim, D.H.
    • Journal of Korean Ophthalmic Optics Society
    • /
    • v.6 no.1
    • /
    • pp.149-153
    • /
    • 2001
  • Three-dimensional thermoluminescence(TL) spectra of LiF: Mg, Cu, Na, Si TL material based on temperature, wavelength and intensity were measured and analyzed. The glow curves were obtained by integration of luminescence intensity for wavelength at each temperature, and various trapping parameters related to the trap formation were determined by analyzing these curves. Computerized glow curve deconvolution(CGCD) method which based on general order kinetics(GOK) model were used for the glow curve analysis. The glow curves of LiF:Mg, Cu, Na, Si TL material were deconvoluted to six isolated glow curves which have peak temperature at 333 K, 374 K, 426 K, 466 K, 483 K and 516 K, respectively. The 466 K main glow peak had an activation energy of 2.06 eV and a kinetic order of 1.05. This TL material was also found to have three recombination centers, 1.80 eV, 2.88 eV and 3.27 eV by TL spectra analysis based on Franck-Condon model. It showed that 2.88 eV is the dominant center, followed by 3.27 eV level, and 1.80 eV center is ascertained as emission center of this material even though its very weak emission intensity.

  • PDF

Evaluation of J$_lc$ and T$_mat$ of aged 1Cr-1Mo-0.25V steel at elevated temperature (시효열화시킨 1Cr-1Mo-0.25V 강의 고온에서의 J$_lc$ 및 T$_mat$ 의 평가)

  • 윤기봉;윤석호;서창민;남승훈
    • Transactions of the Korean Society of Mechanical Engineers
    • /
    • v.18 no.11
    • /
    • pp.2860-2870
    • /
    • 1994
  • When crack are detected in aged turbine rotors of power plants, information on fracture resistance of the aged material at operating temperature is needed for determination of critical loading condition and residual life of the turbine. In this study, fracture toughness (J$_lc$) and tearing modulus(T$_mat$) of virgin and thermally degraded 1Cr-1Mo-0.25V steel, which is one of the most widely used rotor steels, were measured at 538.deg. C according to ASTM E813 and ASTM E1152, respectively. Five kinds of specimen with different degradation levels were prepared by isothermal aging heat treatment at $630^{\circ}C.$ It was observed that J$_lc$ and T$_mat$ value decreased as the degradation level increased. Analysis of microstructures using a scanning electron microscope showed that the decrement of J$_lc$ is related to segregation of impurities at grain boundaries. It was also verified that the DC electric potential drop method is accurate and reliable for crack length monitoring at elevated temperature.