On the inverse Compton scattering model of radio pulsars

Some characteristics of the inverse Compton scattering (ICS) model are reviewed. At least the following properties of radio pulsars can be reproduced in the model: core or central emission beam, one or two hollow emission cones, different emission heights of these components, diverse pulse profiles at various frequencies, linear and circular polarization features of core and cones.Comment: 5 pages, no figures, LaTeX, a proceeding paper for Pacific Rim Conference on Stellar Astrophysics, Aug. 1999, HongKong, Chin

Influence of gaseous annealing environment on the properties of indium-tin-oxide thin films

The influence of postannealing in different gaseous environments on the optical properties of indiu-tin-oxide (ITO) thin films deposited on glass substrates using e-beam evaporation has been systematically investigated. It is found that the annealing conditions affect the optical and electrical properties of the films. Atomic force microscopy, x-ray diffraction, and x-ray photoemission spectroscopy (XPS) were employed to obtain information on the chemical state and crystallization of the films. These data suggest that the chemical states and surface morphology of the ITO film are strongly influenced by the gaseous environment during the annealing process. The XPS data indicate that the observed variations in the optical transmittance can be explained by oxygen incorporation into the film, decomposition of the indium oxide phases, as well as the removal of metallic In. © 2005 American Institute of Physics.published_or_final_versio

The effect of Ga-doped nanocrystalline ZnO electrode on deep-ultraviolet enhanced GaN photodetector

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The effect of thermal annealing on the properties of indium tin oxide thin films

ITO thin films were deposited on glass substrates using e-beam evaporation. The influence of post-deposition annealing on the optical properties of the films was investigated in detail. It was found that the annealing conditions strongly affect the optical properties of the films. The transmittance of films annealed in forming gas (mixed 80% N 2 and H 2) at first increases dramatically with increasing annealing temperatures up to 300°C but then drops for higher temperature anneals around 400°C. An interesting phenomenon is that the transmittance of the darkened film can recover under further 400°C annealing in air. Atomic force microscopy, X-ray diffraction and X-ray photoemission spectroscopy have been employed to obtain information on the chemical state and crystallization of the films. Analysis of this data suggests that incorporation and decomposition reactions of oxygen can be controlled to reversibly change the optical properties of the ITO thin film. © 2005 IEEE.published_or_final_versio

Probing deep level centers in GaN epilayers with variable-frequency capacitance-voltage characteristics of Au/GaN Schottky contacts

Author name used in this publication: X. M. Tao2006-2007 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Probing deep level centers in GaN epilayers with variable-frequency capacitance-voltage characteristics of AuGaN Schottky contacts

Under identical preparation conditions, AuGaN Schottky contacts were prepared on two kinds of GaN epilayers with significantly different background electron concentrations and mobility as well as yellow emission intensities. Current-voltage (I-V) and variable-frequency capacitance-voltage (C-V) characteristics show that the Schottky contacts on the GaN epilayer with a higher background carrier concentration and strong yellow emission exhibit anomalous reverse-bias I-V and C-V characteristics. This is attributed to the presence of deep level centers. Theoretical simulation of the low-frequency C-V curves leads to a determination of the density and energy level position of the deep centers. © 2006 American Institute of Physics.published_or_final_versio

Raman scattering and X-ray diffraction study of neutron irradiated GaN epilayers

Neutron irradiation induced defects and their effects on the carrier concentration of GaN epilayers are investigated with Raman scattering and X-ray diffraction techniques. Relative to the as-grown sample, the neutronirradiated samples exhibit a clear variation in the position and lineshape of the A 1(LO)-mode Raman peak as well as in the fullwidth at half-maximum height (FWHM) of the XRD rocking curves. Careful curve fitting and adequate calculations give the carrier concentrations of the irradiated GaN. It is found that the defects induced by neutron irradiation act as carrier trap centres which capture the electron carriers so that the carrier concentration of the irradiated GaN is reduced. © 2005 IEEE.published_or_final_versio

Effect of osmotic stress on the expression of TRPV4 and BKCa channels and possible interaction with ERK1/2 and p38 in cultured equine chondrocytes

The metabolic activity of articular chondrocytes is influenced by osmotic alterations that occur in articular cartilage secondary to mechanical load. The mechanisms that sense and transduce mechanical signals from cell swelling and initiate volume regulation are poorly understood. The purpose of this study was to investigate how the expression of two putative osmolyte channels [transient receptor potential vanilloid 4 (TRPV4) and large-conductance Ca2+-activated K+ (BKCa)] in chondrocytes is modulated in different osmotic conditions and to examine a potential role for MAPKs in this process. Isolated equine articular chondrocytes were subjected to anisosmotic conditions, and TRPV4 and BKCa channel expression and ERK1/2 and p38 MAPK protein phosphorylation were investigated using Western blotting. Results indicate that the TRPV4 channel contributes to the early stages of hypo-osmotic stress, while the BKCa channel is involved in responding to elevated intracellular Ca2+ and mediating regulatory volume decrease. ERK1/2 is phosphorylated by hypo-osmotic stress (P < 0.001), and p38 MAPK is phosphorylated by hyperosmotic stress (P < 0.001). In addition, this study demonstrates the importance of endogenous ERK1/2 phosphorylation in TRPV4 channel expression, where blocking ERK1/2 by a specific inhibitor (PD98059) prevented increased levels of the TRPV4 channel in cells exposed to hypo-osmotic stress and decreased TRPV4 channel expression to below control levels in iso-osmotic conditions (P < 0.001)

Influence of indium-tin-oxide thin-film quality on reverse leakage current of indium-tin-oxide/n-GaN Schottky contacts

Author name used in this publication: X. M. Tao2006-2007 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

Effects of annealing temperature on the characteristics of Ga-doped ZnO film metal-semiconductor-metal ultraviolet photodetectors

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