8,108 research outputs found

    A Group Theoretical Identification of Integrable Equations in the Li\'enard Type Equation x¹+f(x)x˙+g(x)=0\ddot{x}+f(x)\dot{x}+g(x) = 0 : Part II: Equations having Maximal Lie Point Symmetries

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    In this second of the set of two papers on Lie symmetry analysis of a class of Li\'enard type equation of the form x¹+f(x)x˙+g(x)=0\ddot {x} + f(x)\dot {x} + g(x)= 0, where over dot denotes differentiation with respect to time and f(x)f(x) and g(x)g(x) are smooth functions of their variables, we isolate the equations which possess maximal Lie point symmetries. It is well known that any second order nonlinear ordinary differential equation which admits eight parameter Lie point symmetries is linearizable to free particle equation through point transformation. As a consequence all the identified equations turn out to be linearizable. We also show that one can get maximal Lie point symmetries for the above Li\'enard equation only when fxx=0f_{xx} =0 (subscript denotes differentiation). In addition, we discuss the linearising transformations and solutions for all the nonlinear equations identified in this paper.Comment: Accepted for publication in Journal of Mathematical Physic

    Self-pulsation at 480 GHz from a two-color discrete mode laser diode

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    A discrete mode Fabry-PĂ©rot laser is designed and fabricated to achieve two-color lasing. We demonstrate beating between the two laser modes and self-pulsation at 480 GHz

    Earth Sensor Assembly for the Tropical Rainfall Measuring Mission Observatory

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    EDO Corporation/Barnes Engineering Division (BED) has provided the Tropical Rainfall Measurement Mission (TRMM) Earth Sensor Assembly (ESA), a key element in the TRMM spacecraft's attitude control system. This report documents the history, design, fabrication, assembly, and test of the ESA

    Inverse scattering approach to multiwavelength Fabry-PĂ©rot laser design

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    A class of multiwavelength Fabry-Pérot lasers is introduced where the spectrum is tailored through a patterning of the cavity effective index. The cavity geometry is obtained using an inverse scattering approach and can be designed such that the spacing of discrete Fabry-Pérot lasing modes is limited only by the bandwidth of the inverted gain medium. A specific two-color semiconductor laser with a mode spacing in the THz region is designed, and measurements are presented demonstrating the simultaneous oscillation of the two wavelengths. The nonperiodic effective index profile of the particular two-color device considered is shown to be related to a Moiré or superstructure grating

    A subjective refraction procedure for intellectually disadvantaged patients

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    A subjective refraction procedure for intellectually disadvantaged patients plus instructions to parent/teachers
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