Zhao Song-Qing

The Lie symmetries and conserved quantities of variable-mass nonholonomic system of non-Chetaev's type in phase space

The Lie symmetries and the conserved quantities of a variable mass nonholonomic system of non-Chetaevs type are studied by introducing the infinitesimal transformations of groups in phase space. By using the invariance of the differential equations of motion under the infinitesmal transformations of groups, the determining equations and the restriction equations of the Lie symmetries of the system are established, and the structure equations and the conserved quantities are obtained. An example is given to illustrate the application of the result.

Photovoltaic Characteristic of La0.7Sr0.3MnO3/ZnO p-n Heterojunction

We report on the photovoltaic properties of La0.7Sr0.3MnO3/ZnO heterojunction fabricated by pulsed laser deposition methods. Nanosecond photovoltaic pulses are observed in this junction in the wavelength range from ultraviolet—visible to infrared. A qualitative explanation is presented, based on an analysis of the photovoltaic signals of p-n heterojunction.

Ultraviolet photovoltaic characteristic of MgB2 thin film

Fast photoelectric effects have been observed in MgB2 thin film fabricated by chemical vapour deposition. The rise time was ~10 ns and the full width at half-maximum was ~185 ns for the photovoltaic pulse when the film was irradiated by a 308 nm laser pulse of 25 ns in duration. X-ray diffraction and the scanning electron microscope revealed that the film was polycrystalline with preferred c-axis orientation. We propose that nonequilibrium electron–hole pairs are excited in the grains and grain boundary regions for MgB2 film under ultraviolet laser and then the built-in electric field near the grain boundaries separates carriers, which lead to the appearance of an instant photovoltage.

Ultraviolet laser-induced photovoltaic effects in miscut ferroelectric LiNbO 3 single crystals

This paper investigates the photovoltaic properties of miscut LiNbO3 single crystal with different thicknesses under irradiation of a 248 nm ultraviolet laser pulse with 20 ns duration without an applied bias. Nanosecond photovoltaic response is observed and faster rise time is obtained in thinner samples. In accord with the 248 nm laser duration, the full width at half maximum of the photovoltaic signals keeps a constant of 20 ns. With decrease of the crystal thickness, the photovoltaic sensitivity was improved rapidly at first and then decreased, and the maximum photovoltage occurred at 0.38 mm-thick single crystal. The present results demonstrate that decreasing the LiNbO3 single crystal thickness can obtain faster response time and improve the photovoltaic sensitivity.

Noether's theorem of a rotational relativistic variable mass system

Noethers theory of a rotational relativistic variable mass system is studied. Firstly, Jourdains principle of the rotational relativistic variable mass system is given. Secondly, on the basis of the invariance of the Jourdains principle under the infinitesimal transformations of groups, Noethers theorem and its inverse theorem of the rotational relativistic variable mass system are presented. Finally, an example is given to illustrate the application of the result.

Deposition and characterization of YBCO/CeO2/YSZ/CeO2 multilayers on biaxially textured Ni substrates

CeO2/YSZ/CeO2 buffer layers were deposited on biaxially textured Ni substrates by pulsed laser deposition. The influence of the processing parameters on the texture development of the seed layer CeO2 was investigated. Epitaxial films of YBCO were then grown \textit{in situ} on the CeO2/YSZ (yttria-stabilized ZrO2)/CeO2-buffered Ni substrates. The resulting YBCO conductors exhibited self-field critical current density Jc of more than 1 MA/cm2 at 77K and superconducting transition temperature Tc of about 91K.