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Bahtiyar G. Salamov - One of the best experts on this subject based on the ideXlab platform.

  • Light emission features in ionization-type semiconductor Photographic System
    The Imaging Science Journal, 2004
    Co-Authors: Bahtiyar G. Salamov
    Abstract:

    AbstractLight emission in the UV and visible (blue) range (330–440 nm) generated by the cell of a semiconductor Photographic System and the possibility of locally increasing the gasdischarge light emission for a given photosensitivity of a planar GaAs photodetector is studied. The use of metallic patched concentrators with an area S = 5 × 10−4 cm2 and density 400 cm−2 and an IR light to excite the photocathode of the System leads to a fivefold increase in the gas discharge light intensity. In a System with metallic patched concentrators, the local density of gas-discharge light exceeds the density of uniform gas-discharge light in a semiconductor Photographic System by the same factor as the working area of the photocathode exceeds the total area of the current concentrators. Moreover, the use of current concentrators with a double metallic layer prolongs only the working time of the photodetector, and it does not create additional limitations on the resolution of the photodetector. Filamentation was prim...

  • A semiconductor Photographic System with a modified cell
    The Imaging Science Journal, 1999
    Co-Authors: Bahtiyar G. Salamov
    Abstract:

    This paper studies a modified Photographic cell with symmetrical short gaps between a high-resistivity detector plate and two planar electrodes. The Photographic System with a modified cell is designed to optimize the parameters for the enhancement of the resolution in such applications. The spatial stabilization of the current in the modified cell with a planar GaAs photodetector is studied in a wide range of gas pressure values at 101-342 Torr. Characteristics of the Photographic System are obtained both without and with illumination of the detector plate with light of a particular wavelength range used to control the photoconductivity of the material. The current-voltage characteristic (CVC) and the Photographic cell response are recorded.

  • The cooling semiconductor Photographic System for visualization of the infrared radiation
    The Imaging Science Journal, 1999
    Co-Authors: Bahtiyar G. Salamov, N N Lebedeva, Kemal Colakoglu
    Abstract:

    The possibility of increasing spectral sensitivity of an ionization-type semiconductor Photographic System for a given photosensitivity of an Si: Zn semiconductor detector has been studied. The cooling Photographic System is designed to extend the sensitivity of the Photographic System towards longer infrared (IR) wavelengths. The IR radiation excites the photosensitive semiconductor detector of the device, thus controlling the current density and the visible light emission from the gas discharge gap. The photodetector was irradiated on the back side with infrared radiation in a particular wavelength range which was used to control the photoconductivity of the detector. The size of the discharge gap and the residual gas pressure (60 Torr) are chosen to ensure a sufficiently bright light. The current-voltage characteristics of the discharge cell with a semiconducting photodetector are obtained experimentally.

  • Visualization of the spatial distribution of current densities in a Photographic System with a semiconductor photodetector
    The Imaging Science Journal, 1999
    Co-Authors: Bahtiyar G. Salamov
    Abstract:

    AbstractThis paper studies the visualization of the spatial distribution pattern of current density in a semiconductor Photographic System with a gallium arsenide semiconductor photodetector. The spatial distribution of the current in the filaments was determined by photometric analysis of the gas discharge light emission when a current was passed through a Photographic cell. This method ensured spatial resolution of ~ 10/mm and made it possible to describe quantitatively the distributions involving a drop in current density of ⩾ 102. Transformation of the profile and amplitude of the current density of the filaments in the different regions of the current-voltage characteristic (CVC) has been studied. The filamentation (i.e. an inhomogencous distribution of the current density) was primarily due to the formation of a space charge of positive ions in the discharge gap between the photodetector and a transparent anode plate that changed the discharge from the Townsend type to the glow type.

  • A semiconductor Photographic System for high-speed measurement
    The Imaging Science Journal, 1998
    Co-Authors: Bahtiyar G. Salamov, N N Lebedeva, Kemal Colakoglu, S. Altindal
    Abstract:

    In this paper the applicability of using a Photographic System with a semiconductor photodetector for recording radiation from a pulsed laser is investigated. The semiconductor photodetector is chromium-doped gallium arsenide. With an oscilloscope and a pulsed laser, the speed properties of this kind of Photographic System is investigated experimen tally. This device is promising for applications in slave mode photography of rapid processes in the spectral region of the pulsed Al 2 O 3 :Nd 3+ laser (λ-1.06 μm).

H. Zhao - One of the best experts on this subject based on the ideXlab platform.

  • Testing of polymeric foams at high and medium strain rates
    Polymer Testing, 1997
    Co-Authors: H. Zhao
    Abstract:

    Experimental data of the behaviour of polymeric foams at high and medium strain rates is required in the crash simulations developed in the automotive industry. This paper presents an investigation of particular difficulties in the testing of polymeric foams, using a Split Hopkinson Pressure Bar (SHPB). On the one hand, viscoelastic bars are used to improve the impedance ratio between the bar and the specimen and consequently the accuracy of measurements. A generalised two-gauge method is used to extend this measurement to the complete range of strain (up to 80% of nominal strain), and allows also for performing tests at medium strain rates (5–50 s−1). On the other hand, the assumption of the homogeneity of the strain and stress fields in the specimen is studied, using a high speed Photographic System.

Kemal Colakoglu - One of the best experts on this subject based on the ideXlab platform.

  • The cooling semiconductor Photographic System for visualization of the infrared radiation
    The Imaging Science Journal, 1999
    Co-Authors: Bahtiyar G. Salamov, N N Lebedeva, Kemal Colakoglu
    Abstract:

    The possibility of increasing spectral sensitivity of an ionization-type semiconductor Photographic System for a given photosensitivity of an Si: Zn semiconductor detector has been studied. The cooling Photographic System is designed to extend the sensitivity of the Photographic System towards longer infrared (IR) wavelengths. The IR radiation excites the photosensitive semiconductor detector of the device, thus controlling the current density and the visible light emission from the gas discharge gap. The photodetector was irradiated on the back side with infrared radiation in a particular wavelength range which was used to control the photoconductivity of the detector. The size of the discharge gap and the residual gas pressure (60 Torr) are chosen to ensure a sufficiently bright light. The current-voltage characteristics of the discharge cell with a semiconducting photodetector are obtained experimentally.

  • A semiconductor Photographic System for high-speed measurement
    The Imaging Science Journal, 1998
    Co-Authors: Bahtiyar G. Salamov, N N Lebedeva, Kemal Colakoglu, S. Altindal
    Abstract:

    In this paper the applicability of using a Photographic System with a semiconductor photodetector for recording radiation from a pulsed laser is investigated. The semiconductor photodetector is chromium-doped gallium arsenide. With an oscilloscope and a pulsed laser, the speed properties of this kind of Photographic System is investigated experimen tally. This device is promising for applications in slave mode photography of rapid processes in the spectral region of the pulsed Al 2 O 3 :Nd 3+ laser (λ-1.06 μm).

  • Influence of Gas Medium on the Sensitivity of an Ionization Type Semiconductor Photographic System
    The Imaging Science Journal, 1997
    Co-Authors: Bahtiyar G. Salamov, Kemal Colakoglu, Şemsettin Altındal
    Abstract:

    AbstractThe results of measurements of the characteristics of the ionization-type semiconductor Photographic System with a gas discharge gap on both sides of a semiconducting CaAs:Cr plate are presented. Characteristics were measured under fixed pressure in the interval 600-60 Ton. As a result of this investigation one can see that it is possible to choose optimum conditions for a Photographic ionization System filled by inert gases. Using this gas medium sohvs the problem of retaining semiconductor surface and change of the glow spectrum of gas. Means of increasing the sensitivity and improving the working characteristics are proposed.

  • Enhancement of the Sensitivity of an Ionization Type Semiconductor Photographic System
    The Journal of Photographic Science, 1996
    Co-Authors: Bahtiyar G. Salamov, Kemal Colakoglu, Şemsettin Altındal, M. Özer
    Abstract:

    AbstractThe investigation of the sensitivity of a ionization-type semiconductor Photographic System with higli-resistivity cathode of large diameter (40-60 mm) is described. A photosensitive GaAs cathode with a resistivity ofiO6 Qcm, has been studied. With a gas discharge gap formed by a dielectric separator with the thickness ranging from 40 to 60 pm, a discharge has been formed in air at pressures from 20-760 Torr. The cathode was irradiated on the back with light in a particular wavelength range that was used to control the photoconductivity of the material. The semiconductor material was found to stabilize the discharge. A local change of the resistance inhomogeneity is determined by a local change of discharge radiation intensity. The assessment of the resistance distribution is then based on analysis of the discharge radiation, visualized by a photograph taken through the Sn02 film. Means of increasing the sensitivity and improving the working characteristics are proposed.

N N Lebedeva - One of the best experts on this subject based on the ideXlab platform.

  • The cooling semiconductor Photographic System for visualization of the infrared radiation
    The Imaging Science Journal, 1999
    Co-Authors: Bahtiyar G. Salamov, N N Lebedeva, Kemal Colakoglu
    Abstract:

    The possibility of increasing spectral sensitivity of an ionization-type semiconductor Photographic System for a given photosensitivity of an Si: Zn semiconductor detector has been studied. The cooling Photographic System is designed to extend the sensitivity of the Photographic System towards longer infrared (IR) wavelengths. The IR radiation excites the photosensitive semiconductor detector of the device, thus controlling the current density and the visible light emission from the gas discharge gap. The photodetector was irradiated on the back side with infrared radiation in a particular wavelength range which was used to control the photoconductivity of the detector. The size of the discharge gap and the residual gas pressure (60 Torr) are chosen to ensure a sufficiently bright light. The current-voltage characteristics of the discharge cell with a semiconducting photodetector are obtained experimentally.

  • A semiconductor Photographic System for high-speed measurement
    The Imaging Science Journal, 1998
    Co-Authors: Bahtiyar G. Salamov, N N Lebedeva, Kemal Colakoglu, S. Altindal
    Abstract:

    In this paper the applicability of using a Photographic System with a semiconductor photodetector for recording radiation from a pulsed laser is investigated. The semiconductor photodetector is chromium-doped gallium arsenide. With an oscilloscope and a pulsed laser, the speed properties of this kind of Photographic System is investigated experimen tally. This device is promising for applications in slave mode photography of rapid processes in the spectral region of the pulsed Al 2 O 3 :Nd 3+ laser (λ-1.06 μm).

  • Visualization of electrical inhomogeneities in high-ohmic semiconductor plates by an ionization-type Photographic System
    Journal of Physics D: Applied Physics, 1994
    Co-Authors: N N Lebedeva, Bahtiyar G. Salamov, Bulent G. Akinoglu, K.r. Allakhverdiev
    Abstract:

    A device for rapid visualization of electrical and spatial inhomogeneities of a semi-insulating GaAs (p>or=106 Omega cm) is described. This visualizer is a modification of the ionization type Photographic System in which a semiconducting plate is placed between transparent plane parallel electrodes in the gas discharge cell. The gas discharge gaps are formed between free surfaces of the semiconductor and electrodes. When a voltage is applied to the electrodes a discharge luminescence glows in the gap under uniform infrared illumination of the semiconductor. The uniformity of glowing over the semiconductor area is determined by electrical homogeneity and infrared absorptivity of the material. The main discharge glow patterns on both sides and after chemical etching are similar, which reflects the fact that the structural defects are continuous within the plate. The observed patterns give information about EL2 centres in the GaAs semiconductor. Technical data of the ionization-type visualizer of electrical inhomogeneities in a semiconducting plate are given.

  • Image recording on bismuth film in an ionization-type Photographic System
    The Journal of Photographic Science, 1991
    Co-Authors: A.k. Zeinally, N N Lebedeva, L.g. Paritski, B.g. Salamov
    Abstract:

    AbstractThe mechanism of image formation in bismuth film in an ionization-type Photographic System has been studied. An original method which allows the observation of the light transmission kinetics of a bismuth film in a discharge process has been proposed. Transmission spectra of bismuth films are measured after different exposure times in the discharge System. Their identity with Bi20, oxide has been shown. Due to differences in the optical properties of bismuth and Bi2O3, the production of a stable irreversible Photographic image is realized.

Wei Feng Wen - One of the best experts on this subject based on the ideXlab platform.

  • Ultra-high speed photoelectric imaging System and applications
    32nd International Congress on High-Speed Imaging and Photonics, 2019
    Co-Authors: Xin Cai Zhao, Ning Wen Liu, Zheng Fei Xiao, Xu Wang, Wei Feng Wen
    Abstract:

    Ultra-high speed photoelectric Photographic System is one of the important methods to study the image parameters of ultrafast physical process. This paper proposes a method of combining multi-group prism optical splitter, super shutter selection image intensifier with adjustable delay and CCD picture acquisition. The proposed method solves the problem of the image cutting in the small aperture backlight illumination experiment using the pyramid-type photoelectric camera. Several ultra-high speed Photographic Systems are developed, which can be used for the shadow photography, and realize ultra high speed photoelectric Photographic System with 43 mm-1 spatial resolution, 2x108 images/s speed, and the capability of capturing 8 images continuously (Fig. 1). In order to adapt to the strong electromagnetic interference test environment, the Photographic System adopts all optical fiber communication, signal interpretation and locking, unit modularization and other technical schemes to avoid the loss of signal in the image transmission and the System mistriggering problems. The developed camera has good application to such dynamic experiments as plasma physics and the interaction between laser and substance, and satisfactory results have been achieved.