Now showing items 31-40 of 222
Energy conditions in non-Riemannian spacetimes
(Elsevier, 1994-12-26)
We interpret the energy conditions in non-Riemannian spacetimes by applying them to a family of stationary, axially symmetric solutions for the gravitational field equations for an Einstein-Cartan theory in a Riemann-Cartan ...
Chirped pulse amplification in an erbium-doped fiber oscillator/ erbium-doped fiber amplifier system
(Elsevier, 1994-03-15)
Chirped pulse amplification in erbium fibers is demonstrated. A passively mode locked erbium-doped fiber laser source provides the seed pulses for an erbium-doped fiber amplifier. The system produces femtosecond pulses at ...
Order‐disorder and magnetic exchange interactions in substituted strontium hexaferrite SrAxFe12−xO19(A=Ga, In)
(The American Institute of Physics, 1994-05-15)
The unusual magnetic behavior of the 12k site in SrGaxFe12−xO19 (0.3≤x≤6.0) and SrInxFe12−xO19 (0.3≤x≤1.4) has been investigated by means of 57Fe Mössbauer spectroscopy at 298 K. The bifurcation of the 12k Mössbauer ...
Digital synthesis of pulse shapes in real time for high resolution radiation spectroscopy
(Elsevier, 1994-06-15)
Techniques have been developed for the synthesis of pulse shapes using fast digital schemes in place of the traditional analog methods of pulse shaping. Efficient recursive algorithms have been developed that allow real ...
Quantum state transfer in double‐quantum‐well devices
(The American Institute of Physics, 1994-12-01)
A Monte Carlo simulation of double‐quantum‐well (DQW) devices is presented in view of analyzing the quantum state transfer (QST) effect. Different structures, based on the AlGaAs/GaAs system, were simulated at 77 and 300 ...
Temporal behavior of resonant‐optical‐waveguide phase‐locked diode laser arrays
(The American Institute of Physics, 1994-02-14)
Measurements of the temporal and spatial behavior of resonant optical waveguide (ROW) laser arrays with significant interelement loss reveal the presence of sustained self‐pulsations in the output intensity of the laser. ...
Spinning fluid cosmologies in Einstein-Cartan theory
(IOP Publishing Ltd, 1994-09-01)
We consider self-consistent spinning fluid cosmologies in both general relativity in Riemannian spacetimes and Einstein-Cartan theory in Riemann-Cartan spacetimes. First we extend slightly the cosmological calculation of ...
Theory of the spiral core in excitable media
(Elsevier, 1994-01-01)
A rigorous asymptotic spiral solution to an excitable reaction diffusion system is found by separating space into two scaling regions: an "outer region", having the same spatial scaling as the overall spiral structure, ...
Electron emission: From the Fowler–Nordheim relation to the Child–Langmuir law
(The American Institute of Physics, 1994-06)
Universal voltage‐current characteristics are presented for a planar diode, showing the general transition from the Fowler–Nordheim relation to the Child–Langmuir law. These curves are normalized to the intrinsic scales ...
Additive pulse mode-locking using a birefringent optical fiber
(Elsevier, 1994-01-15)
A powerful and increasingly common method to mode-lock a variety of lasers is additive pulse mode-locking (APM). In this technique, a nonlinear medium is placed in an external cavity which is coupled to the main laser ...