Mirrorless laser action by randomly distributed feedback in amplifying disordered media with scattering centers

Received: 12 August 1997/Revised version: 16 October 1997     

An improved theoretical model of the dc characteristics of metal-semiconductor field effect transistors

Received: 15 August 1997/Accepted: 13 November 1997     

Heating of cold cesium atoms by blue-detuned laser radiation

Received: 12 March 1997/Revised version: 30 July 1997     

Improved output characteristics of a vacuum ultraviolet xenon gas jet discharge lamp with a magnetic field

Received: 30 September 1996/Revised version: 10 January 1997     

Silicon vacancies in 3C-SiC observed by positron lifetime and electron spin resonance

54 , 2512 (1996)]. The trapping coefficient of single-negative silicon vacancies was also derived. Received: 25 August 1997/Accepted: 27 March 1998     

Pressure effects during pulsed-laser deposition of barium titanate thin films

2 , Ar) in a broad pressure range (10^-7–1 mbar) are correlated to the plasma expansion dynamics. It is found that the deposited films present an excess of Ba in the intermediate pressure range (10^-2<P<10^-1 mbar) and a peaked distribution of Ba to Ti atoms ratio, that is not related to either the substrate temperature or the nature of the gas environment. The results are discussed in terms of the dependence of the plume length (L_P) on the gas pressure and the existence of scattering processes for distances (d) from the target lower than L_P and the diffusion of the ejected species for L_P<d. Received: 7 November 1997/Accepted: 8 November 1997     

Structural stability of heat-treated CoN/CN soft X-ray multilayers fabricated by dual-facing-target sputtering

286 , 176 (1996)]. (1) The interdiffusion critical wavelengths were calculated as 2.00–2.04 nm at temperatures ranging from 473 to 523 K, which is equal to those of Co/C multilayers within the experimental error, indicating that the interdiffusion behaviours in the CoN/CN multilayers are still decided by the thermodynamic properties of the Co-C system. (2) The effective interdiffusivities and macroscopic diffusion coefficients are smaller. (3) The activation energy for diffusion is larger. The features imply that it is possible to improve the thermal stability of Co/C multilayers by doping with N atoms. The high-temperature annealing results imply that the destructive threshold of the CoN/CN multilayers is 100–200 °C higher than that of Co/C multilayers. The small-angle X-ray diffraction of CoN/CN soft X-ray multilayers indicates that the period expansion of the multilayers is only 4% at 400 °C, and the interface pattern still exists even if they were annealed at 700 °C. The large-angle X-ray diffraction and transmission electron microscopy analysis reveal that the crystalline process is significantly retarded if doped with N atoms, leading to a smaller grain size at higher annealing temperatures. The significant improvement of the thermal stability can be interpreted with Raman spectroscopy and X-ray photoelectron spectroscopy analysis. The Raman spectra give the evidence that the formation of the sp³ bonding in the CN sublayers can be suppressed effectively by doping with N atoms, and thus the period expansion resulting from the changes in the density of CN layers can be decreased considerably. The X-ray photoelectron spectra give information about existence of the strong covalent bonding between N atoms and the ionic bonding between Co and N atoms, which can slow down the tendency of the structural relaxation. The interstitial N atoms decrease the mobility of Co atoms, and thus the fcc Co and hcp Co coexist even though the annealing temperature is much higher than the phase transformation temperature of 420 °C, leading to the suppression of the grain growth. Received: 29 May 1997/Accepted: 8 September 1997     

On the Dromion Interaction of the JMKP Equation: Equipotential Plots

The dromion interaction of the (3+1)-dimensional conditional integrable model, Jimbo-Miwa-Kadomtsev-Petviashvilli (JMKP) system, is re-studied by means of the equipotential surface plots. The result shows that the interaction among dromions of the JMKP system is elastic which corrects the conclusion of our previous paper (J. Math. Phys. 38 (1997) 3123). firtherrnore, the interaction is also irrotational. That is to say, there are not exchanges of any physical quantities like energy, momentum and angular momentum.     

Living polymers in random media: a 2D Monte-Carlo investigation on a square lattice

The evolution of the mean chain length and mean end to end square radius of a two dimensional system of living polymers at constant monomer concentration is studied as a function of the obstacle density . The fact that the system adapts the mean chain length in order to reduce the entropic constraint does not lead to a different asymptotic dependence of on than what is observed for dead polymers. The change of the molecular weight distribution form in the presence of obstacles suggests that a Levy flight could appear in system of wormlike micelles in a porous medium. Received: 1 September 1997 / Received in final form: 22 January 1998 / Accepted: 30 January 1998     

Photoablation and microstructuring of polyestercarbonates and their blends with a XeCl excimer laser

Received: 23 October 1997/Accepted: 18 November 1997     

Real-time volumetric growth rate measurements and feedback control of three-dimensional laser chemical vapor deposition

Received: 4 June 1997/Accepted: 12 June 1997     

PET surface modifications by treatment with monochromatic excimer UV lamps

Received: 11 August 1997/Accepted: 14 August 1997     

Prevention of micropipes and voids at β-SiC/Si(100) interfaces

Received: 23 April 1997/Accepted: 30 July 1997     

Reflection properties of metallic photonic crystals

Received: 10 November 1997/Accepted: 16 November 1997     

Laser-induced dry etching of integrated InP microlenses

Received: 4 June 1997/Accepted: 13 June 1997     

Dynamics of the hydrodynamical growth of columns on silicon exposed to ArF excimer-laser irradiation

Received: 6 January 1997/Accepted: 8 July 1997     

On thickness dependence of electrical and optical properties of Te thin films

Received: 1 July 1997/Accepted: 6 August 1997     

Neurons from rat brain coupled to transistors

Received: 2 June 1997/Accepted: 3 June 1997     

Investigation of ripple structures of thin polycrystalline Co films by magnetic force microscopy

Received: 14 August 1997/Accepted: 14 August 1997     

Effects of temperature and pressure on CVD diamond growth from the C-H-O system

Received: 28 August 1997/Accepted: 18 November 1997