Browsing Department of Physics & Materials Science by Issue Date
Now showing items 41-60 of 158
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A study of the Equatorial Ionosphere over Nairobi During selected magnetically disturbed and quiet times for the year 2009 Using co-located instruments
(IJARPS, 2014)Investigation of the behavior of the Equatorial Ionosphere over Nairobi-Kenya within the East Africa region is done using co-located instruments, that is, SCINDA-GPS system and a Magnetometer ( MAGDAS). This was done for ... -
Complex Spacetime Frame: Four-Vector Identities and Tensors
(Scientific Research Publishing, 2014)This paper provides derivation of some basic identities for complex four-component vectors defined in a complex four-dimensional spacetime frame specified by an imaginary temporal axis. The resulting four-vector identities ... -
Investigation of the effect of film thickness on the optical properties of amorphous Se85-xte15sbx thin films
(Africa Journal of Physical Sciences, 2014)Amorphous thin films of Se85-xTe15Sbx (x = 0.0, 0.5, 2.5, and 5.0 at. %) deposited by flash evaporation technique, have been investigated in the wavelength range of 500nm-3000nm. It is found that the effect of increasing ... -
Energy Resources in East Africa
(Springer, Cham, 2015)When talking about East Africa, traditionally this refers to the states of Kenya, Uganda and Tanzania with a combined population of over 120 million people in 2014. The three countries have a long history of association ... -
First Order Expectation Values of Electron Correlation Operators for Two-Electron Atoms
(SPG, 2015)Simple analytic first-order wave functions corresponding to two-electron atoms electron correlation operators are obtained by reduction of the Rayleigh-Schrödinger first order perturbation equation to that of one-electron ... -
Mathematical model of pneumonia and HIV/AIDS coinfection in the presence of protection
(2015)In this paper, a deterministic co-infection model incorporating protection from infection for both pneumonia infection and HIV/AIDS is considered. The model is shown to be positively invariant as well as bounded. Specifically ... -
Enhancing light absorption and lifetime stability of organic solar cells using pentacene encapsulation
(SA Institute of Physics, 2015). In the present work we compare the performance of a pristine P3HT:PCBM based bulk heterojunction solar cell with a device incorporated with pentacene encapsulated Ag nanoparticles. Encapsulation has been achieved through ... -
On the steady MHD couette flow between two infinite parallel plates in an uniform transverse magnetic field
(2015)In this paper we consider laminar viscous incompressible fluid between two infinite parallel plates when the upper plate is moving with constant velocity Uo and the lower plate is held stationary under the influence of ... -
Progressively accurate WKB approximations through factorization and successive boost transformations
(Research gate, 2015)This paper develops a procedure for obtaining progressively improving approximate solutions of the WKB (semiclassical ) model of the stationary Schroedinger equation through factorization and successive boost transformations ... -
Composite Hermite and Anti-Hermite Polynomials
(Scientific Research Publishing, 2015)The Weber-Hermite differential equation, obtained as the dimensionless form of the stationary Schroedinger equation for a linear harmonic oscillator in quantum mechanics, has been expressed in a generalized form through ... -
Stability Investigation in the Optical Properties of Thermally Evaporated Ge5Se95-x Znx Thin Films
(University of Nairobi, Kenya, 2015)Selenium-based chalcogenides are useful in telecommunication devices like infrared optics and threshold switching devices. The investigated system of Ge5Se95-xZnx (0.0 ≤ x ≤ 4 at.%) has been prepared from high purity ... -
Role of bismuth and substrate temperature on the optical properties of some flash evaporated se100-x bix glassy system
(University of Nairobi, Kenya, 2015)Chalcogenide glasses are very important in the modern technology especially selenium-based. These glasses are sensitive to electromagnetic radiation useful in the infrared optics. The study investigated the effect of ... -
Ab Initio study of the electronic and optical properties of hexagonal and cubic Ge2Sb2Te5
(African Review of Physics, 2015-04)The electronic and optical properties of hexagonal and cubic Ge 2 Sb 2 Te 5 have been calculated using the QUANTUM ESPRESSO and Yambo codes. The study has considered the variation of electronic band gaps with lattice ... -
Ab initio study of the structural, vibrational and thermal properties of Ge2Sb2Te5
(International Journal of Computational Materials Science, 2015-05-12)The structural, vibrational and thermal properties of hexagonal as well as cubic Ge2Sb2Te5 (GST) have been calculated from first principles. The relative stability of the possible stacking sequences of hexagonal GST has ... -
Ab initio study of the structural, vibrational and thermal properties of Ge2Sb2Te5
(Imperial College Press, 2015-06-12)The structural, vibrational and thermal properties of hexagonal as well as cubic Ge2Sb2Te5 (GST) have been calculated from first principles. The relative stability of the possible stacking sequences of hexagonal GST has ... -
Finite Difference Analysis of 2-Dimensional Acoustic Wave with a Signal Function
(2015-12-09)This paper describes progress on a two dimensional numerical simulation of acoustic wave propagation that has been developed to visualize the propagation of acoustic wave fronts and to provide time-domain signal. In this ... -
Global Energy Perspective
(Springer, Cham, 2016)“Energy is everywhere in different forms and it is needed by everyone and yet it is not always available for everybody. If you have it, you must protect it. If you do not have it, you must get it at any cost. Which other ... -
Quantum thermodynamics of a strongly interacting bose-fermi mixture in a three-dimensional anharmonic potential
(Research gate, 2016)ABSTRACT Thermodynamic properties of Bose-Fermi mixture at ultra-low temperatures were studied using perturbation theory in three Cartesian coordinates. The Hamiltonian for the mixture was developed in terms of boson-boson, ... -
On a complex spacetime frame: new foundation for physics and mathematics
(Research gate, 2016)This paper provides a derivation of a unit vector specifying the temporal axis of four-dimensional space-time frame as an imaginary axis in the direction of light or general wave propagation. The basic elements of the ... -
Fundamental quantum noise in a fully quantized degenerate parametric amplification process
(Research gate, 2016)An exact analytical solution of the time-dependent Schroedinger equation for a fully quantized degenerate parametric amplification process generated by quantized multi-mode pump photons provides a quantized multi-photon ...