Air Cooler for Crystal Growth in a Laboratory Tube Furnace

Crystallography Reports - A new air cooler design (“specific two-level crystallization incubator”) with a specific arrangement of laboratory vessels by levels and double-branch air...     

Crystallization shelves for laboratory furnaces

Several designs of air coolers (modular bilateral “crystallization shelves”), installed in laboratory furnaces are presented. The setup allows easy regulation and simultaneous crystallization of several substances at different temperature gradients, shapes of crystallization fronts and rate intervals, with the purpose of obtaining crystals. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)     

Crystallization tests bench

A model of an air-cooled tube (“air-heat saw”) installed in a laboratory tube furnace is presented. The setup (“crystallization tests bench”) allows easy regulation and simultaneous crystallization tests of a series of different crystallization parameters in crucible columns, enabling fast studies of obtaining crystals from materials with unknown crystallization parameters. The relationships between the crystallization rate and parameters of air-cooled tube are given and numerically analyzed. This method can also be applied in crucible or chamber furnaces.     

Conversion of high-order Laguerre-Gaussian beams into Bessel beams of increased, reduced or zeroth order by use of a helical axicon

We propose a new method for transformation of a Laguerre-Gaussian beam of azimuthal index l and radial index n = 0 (LG_l,0) into a vortex, diverging or nondiverging Bessel beam, which can have increased or decreased phase singularity order, or into a zeroth order Bessel beam, by means of a helical axicon. The Bessel beam divergence or nondivergence depends upon the waist position of the input Laguerre-Gaussian beam, regarding the plane where the helical axicon is situated.The expressions for the amplitude and the intensity distribution of the diffracted wave field, in the process of Fresnel diffraction, are deduced using the stationary phase method. The theoretical analysis for the vortex radius and the maximum propagation distance of the Bessel beams obtained is presented.