An analytical formula of the emittance of a field emitter is given. In contrast to thermal and photoemission, such a formula contains complexity due to the multidimensional nature of the source. A formulation of emittance is given for oneand three-dimensional 3D field emitters. The 3D formulation makes use of the point charge model of a unit cell emitter coupled with a trajectory analysis to fo...

In view of the possible role of electron transfer in biology and medicine, and wide distribution of polyenes in living nature, we consider the electron transfer mechanism of geometrical cis-trans isomerization as an important route which can play a key role in many photochemical and biological processes. The various mechanisms of geometrical cis-trans isomerization mediated by electron transfer...

introduction:nitrate entrance to water bodies can cause eutrophication and decrease quality of them, furthermore it can effect on human health so concentration of nitrate must be at defined standard level. there are several methods for reduction or removal of nitrate in water such as ion exchange, reverse osmosis, electrodialysis and denitrification. microbial denitrification of nitrate in anox...

The study of structural dynamics of complex macromolecular crystals using electrons requires bunches of sufficient coherence and charge. We present diffraction patterns from graphite, obtained with bunches from an ultracold electron source, based on femtosecond near-threshold photoionization of a laser-cooled atomic gas. By varying the photoionization wavelength, we change the effective source ...

Laser accelerators offer the promise of producing attosecond electron bunches from a compact accelerator. Electron source requirements for laser accelerators are challenging in several respects, but are achievable. We discuss these requirements, and propose an injector design. Simulation and design work for essential components for a laser accelerator electron source suitable for a high energy ...

We report on the electron analog of the single-photon gun. On-demand single-electron injection in a quantum conductor was obtained using a quantum dot connected to the conductor via a tunnel barrier. Electron emission was triggered by the application of a potential step that compensated for the dot-charging energy. Depending on the barrier transparency, the quantum emission time ranged from 0.1...

We have continued the basic research to develop the photocathodes for the polarized electron source and to construct the guns for the high energy accelerator , such as e + e ? linear colliders. Four subjects, (1) photocathode development of strained layer superlattice, (2) photoluminescence study of spin relaxation inside the cathode, (3) study of eld emission dark current, and (4) gun design a...

An electron beam evaporator has been assembled, tested and used for deposition of thin nickel films. Flux and deposition rates has been measured with an oscillating quartz crystal monitor (QCM), an ion sensor wire, and visible deposition on a mirror on front of the evaporator. A thin nickel rod of 2 mm diameter was found to improve the pressure in comparison to a 6-mm nickel rod. The flux was t...

In this paper, drain-source current, transconductance and cutoff frequency in AlGaN/GaN high electron mobility transistors have been investigated. In order to obtain parameters of exact AlGaN/GaN high electron mobility transistors such as electron density, the wave function, band gap, polarization charge, effective mass and dielectric constant, the hydrostatic pressure and temperature effects a...