Current Issue : July - September Volume : 2012 Issue Number : 3 Articles : 6 Articles
We investigate a nonlinear realization of the Lorentz transformation defined in 4-dimensional spacetime, and the corresponding\r\ninvariant interval. This new interval is not a quadratic form in the standardMinkowski spacetime, then we search for a description\r\nwhere it becomes a quadratic form in an infinite dimensional vector space. In this extended space, we show how to generate two\r\nclasses of nonlinear transformations, which form a group and interpret the non-linear transformation as compatible relations\r\nbetween atlas of a Lyra manifold....
The AC conductivity and dielectric parameters of the glassy system of (70-x) V2O5Ã?·x(Zn/Pb)Ã?·10SrOÃ?·20FeO (x = 0, 5, 10, and\r\n15) glasses have been investigated. The frequency and temperature dependence of dielectric constant (e) and dielectric loss (e)\r\nis studied in the frequency range 100 Hzââ?¬â??5MHz and in the temperature range 300ââ?¬â??460 K. Dielectric dispersion is observed in\r\nall samples as Zn/Pb increase content in the (70-x)V2O5Ã?·x (Zn/Pb)Ã?·10SrOÃ?·20FeO systems. These results are explained on the\r\nbasis of a Debye-type relaxation. It is also observed that the activation energy increases on increasing the Zn/Pb contents in this\r\nsystem....
The applications of ferrimagnetic oxides, or ferrites, in the last 10 years are reviewed, including thin films and nanoparticles.\r\nThe general features of the three basic crystal systems and their magnetic structures are briefly discussed, followed by the\r\nmost interesting applications in electronic circuits as inductors, in high-frequency systems, in power delivering devices, in\r\nelectromagnetic interference suppression, and in biotechnology. As the field is considerably large, an effort has been made to\r\ninclude the original references discussing each particular application on a more detailed manner....
This paper reviews the use of optical sum frequency generation (SFG) and second harmonic generation (SHG) microscopy under\r\nultra-high vacuum (UHV) conditions to observe the dynamics of a hydrogen terminated Si(111)1 Ã?â?? 1 surface. First, we took SFG\r\nand SHG microscopic images of the surface after IR light pulse irradiation and found that the SHG and nonresonant SFG signals\r\nwere enhanced, probably due to the formation of dangling bonds after hydrogen desorption. Second, we observed time-resolved\r\nSFG intensity images of a Hââ?¬â??Si(111)1 Ã?â?? 1 surface. After visible pump light irradiation, the nonresonant SFG signal increased at\r\nprobe delay time 0 ps and then decreased over a life time of 565 ps. The resonant SFG signal reduced dramatically at 0 ps and then\r\nrecovered with an anisotropic line shape over a life time of 305 ps. The areas of modulated SFG signals at delay time 277 ps were\r\nexpanded with an anisotropic aspect. Finally, we observed SFG intensity images of hydrogen deficiency on a Si(111)1 Ã?â?? 1 surface as\r\na function of temperature. These images of the Hââ?¬â??Si(111) surface, taken with a spatial resolution of 5 Ã?µm at several temperatures\r\nfrom 572 to 744 K, showed that the hydrogen desorbs homogeneously....
It is shown that Schr�¨odingerâ��s equation may be derived from three postulates. The first is a kind of statistical metamorphosis of\r\nclassical mechanics, a set of two relations which are obtained from the canonical equations of particle mechanics by replacing all\r\nobservables by statistical averages. The second is a local conservation law of probability with a probability current which takes the\r\nform of a gradient. The third is a principle of maximal disorder as realized by the requirement of minimal Fisher information.\r\nThe rule for calculating expectation values is obtained from a fourth postulate, the requirement of energy conservation in the\r\nmean. The fact that all these basic relations of quantum theory may be derived from premises which are statistical in character is\r\ninterpreted as a strong argument in favor of the statistical interpretation of quantum mechanics. The structures of quantum theory\r\nand classical statistical theories are compared, and some fundamental differences are identified....
The paper describes two different approaches to ultrasonicmeasurements of temperature in aqueous solutions. The first approach\r\nuses two narrowband ultrasonic transducers and support electronics that form an oscillating sensor which output frequency is\r\nrelated to the measured temperature. This low-cost sensor demonstrated sensitivity of about 40Hz/K at the distance of 190mm\r\nand the operating frequency of about 25 kHz. The second approach utilised pulse-echo mode at the centre frequency of 20 MHz.\r\nThe reflector featured a cavity that was filled with deionised water. The ultrasound propagation delay in the cavity was related\r\nto the temperature in the solution. The experiments were conducted for deionised water, and solutions of sodium persulfate,\r\nsodium chloride, and acetic acid with concentrations up to 0.5 M. In the experiments (conducted within the temperature range\r\nfrom 15 to 30?C), we observed increases in the ultrasound velocity for increased temperatures and concentrations as was expected.\r\nMeasurement results were compared with literature data for pure and seawater. It was concluded that ultrasonic measurements\r\nof temperature were conducted with the resolution well below 0.1K for both methods. Advantages of ultrasonic temperature\r\nmeasurements over conventional thermometers were discussed....
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