Spatial light modulator as a reconfigurable intracavity dispersive element for tunable lasers

An improved approach for narrow-band wavelength selection in tunable lasers is described. To provide the tunability, a reconfigurable diffractive optical element (DOE) based on a programmable spatial light modulator (PSLM) is applied. With a proper choice of the phase transfer function of the PSLM, the device can be used as a dispersive intra-cavity component for precise tuning within the lasing spectral band of a solid-state dye laser. The suggested design allows avoiding the mechanical movement of any cavity components. The tunability performance and simulation are demonstrated using the Fourier optics method.     

A theoretical-spectroscopy, ab initio-based study of the electronic ground state of SbH3

For the stibine isotopologue , we report improved theoretical calculations of the vibrational energies below 8000 cm⁻¹ and simulations of the rovibrational spectrum in the 0-8000 cm⁻¹ region. The calculations are based on a refined ab initio potential energy surface and on a new dipole moment surface obtained at the coupled cluster CCSD(T) level. The theoretical results are compared with the available experimental data in order to validate the ab initio surfaces and the TROVE computational method [Yurchenko SN, Thiel W, Jensen P. J Mol Spectrosc 2007;245:126-40] for calculating rovibrational energies and simulating rovibrational spectra of arbitrary molecules in isolated electronic states. A number of predicted vibrational energies of are provided in order to stimulate new experimental investigations of stibine. The local-mode character of the vibrations in stibine is demonstrated through an analysis of the results in terms of local-mode theory.     

Control of octahedral tilts and magnetic properties of perovskite oxide heterostructures by substrate symmetry

Perovskite transition-metal oxides are networks of corner-sharing octahedra whose tilts and distortions are known to affect their electronic and magnetic properties. We report calculations on a model interfacial structure which avoids chemical influences and show that the symmetry mismatch imposes an interfacial layer with distortion modes that do not exist in either bulk material, creating new interface properties driven by symmetry alone. Depending on the resistance of the octahedra to deformation, the interface layer can be as small as one unit cell or extend deep into the thin film.     

Quality control of coatings with the help of local electrochemical analysis

Local electrochemical analysis with a pressed-on electrochemical cell is suggested for the estimation of the quality of coatings protecting the surface of materials, for the detection of different defects and for the control of the thickness and composition of coatings. The suggested local electrochemical analysis allows the determination of the throwing power of the electrolytes used in electrodepositions. Received: 8 December 1997 / Accepted: 21 August 1998     

Arithmetic properties of integers with missing digits: distribution in residue classes

We show that numbers with missing digits are in average well-distributed in residue classes mod m where averaging is taken over m.     

Direct simulation monte carlo of pulsed laser ablation of metals with clusterization processes in vapor

A mathematical model is proposed to describe laser ablation of metals in vacuum under the action of nanosecond laser pulses of moderate intensity taking into account the processes of cluster formation and decay in the vapor cloud. To describe the laser radiation absorption and metal heating, the thermal model based on the unsteady one-dimensional heat equation with a volume heat source is used, and the method of statistical modelling is employed for modelling vapor expansion and the processes of cluster formation. The efficiency of the proposed complex model is considered by the example of pulsed laser ablation of a niobium target. The work was supported financially by INTAS (grant No. 03-51-5208).     

Prolonged plasma clot lysis induced by acyl-derivatives of urokinase in vitro

Two acyl-derivatives of urokinase, p-trimethylam inocinnamoyl-urokinase (TMAC-Uk) and p-guanidinobenzoyl-urokinase (GB-Uk), reactivating with different rates (k _reac were 6×10^?4/s and 6×10^?5/s, respectively) were prepared. In comparison with free urokinase, acyl-activators were more stable in human plasma, and their stability increased with the decrease in the reactivation rate. Plasma clotlysis induced by all three agents was time- and dose-dependent, but acyl-activators caused a more prolonged fibrinolysis and lengthened lag-phase than free urokinase. Slowly reactivating GB-Uk induced the most long-lasting clotlysis, whereas free urokinase was more effective for the first 3 h. A combination of GB-Uk with low dose urokinase promoted the long-lasting clotlysis with the shortened lag-phase.