Open Access. Powered by Scholars. Published by Universities.®
- Publication
Articles 1 - 2 of 2
Full-Text Articles in Physics
Low Energy Electron Gun Power Control Unit, Chad Fish, Jr Dennison
Low Energy Electron Gun Power Control Unit, Chad Fish, Jr Dennison
Senior Theses and Projects
Near-Earth orbiting spacecraft are subject to a variety of physical environmental elements. Of these, natural space plasma and solar radiation produce spacecraft charging. Spacecraft charging consists of surface (external) and deep (internal) dielectric charging.
Natural space plasma is composed of electrons and positively charged atoms called ions. The plasma is generated by energy from solar radiation and high energy particles emitted by geomagnetic storms. The electrons produce a negative current and the ions produce a positive current. Positive photoelectron currents produced by solar radiation of spacecraft surfaces also add to the electrical fluxesi.
As spacecraft move through the …
Physisorbed Co On Ionic Crystals: An Extended Beg Spin-Lattice Model Of Adsorbed Dipolar Molecules, T. E. Burns, Jr Dennison
Physisorbed Co On Ionic Crystals: An Extended Beg Spin-Lattice Model Of Adsorbed Dipolar Molecules, T. E. Burns, Jr Dennison
Journal Articles
The 2D dielectric phases and phase transitions of adsorbed dipolar molecules are studied using a dilute spin-one Ising model. The spin-one formulation assigns a spin Si = ±1 to a (up/down) dipole occupying a lattice site i adsorbed perpendicular to the substrate surface and Si = 0 to unoccupied sites. We relate the mean field expression for the spin-model interaction energy to a more detailed microscopic model involving dipolar, quadrupolar and dispersive interactions beyond nearest neighbor. Analytic solutions in the mean field approximation are discussed for dipole-orientation order-disorder transitions and ferroelectric-to-antiferroelectric transitions as a function of temperature and …