Development of a roller quenching apparatus for the production of amorphous phases

The details of an apparatus designed to produce amorphous phases by rapid quenching from the melt are described. A drop of molten material is squeezed between two copper rollers rotating against each other at 5000 RPM and a thin foil of the material is produced. The system produces cooling rates of the order of 105 K/sec. Details of the development and construction are mentioned

Behaviour of ultrasonic velocities in amorphous Se<SUB>90</SUB>Ge<SUB>10</SUB> and Se<SUB>85</SUB>Ge<SUB>15</SUB> alloys near their glass transition

Precise measurements of 10 MHz frequency longitudinal and shear wave velocities are reported in amorphous SeGe alloys near their glass transition temperature Tg . There is a sharp decrease of the velocities near Tg , but the reduction in velocities appears smaller than expected

Preparation of Zinc-Sulfide Thin Films in the Presence of Sodium Tartrate as a complexing agent

The article offers information on the experiment done for the electrodeposition of zinc-sulfide (ZnS) thin films on the titanium substrate in the presence of sodium tartrate as a complexing agent. It states that the electrodeposition process has several advantages such as the possibility for large-scale production and minimum waste of components. It mentions that depositions were carried out by varying the deposition potential to determine the optimal conditions of deposition of ZnS thin film

Study of the electronic and optical bonding properties of doped SnO2

Numerous metal oxide semiconductor materials were reported to be usable as semiconductor gas sensor, such as ZnO, SnO2, TiO2 and so on. These materials have non-stoichiometric structure so free electron originating from oxygen vacancies contribute to electrical conductivity. The interaction of different gas compounds with an oxide surface may lead to changes in the lattice oxygen content at the surface in addition to changes in the amount of adsorbed species. The samples of Cu doped SnO2 have been synthesized by solid-state reaction method. Some aspects of crystal structure of the compound at room temperature were studied using X-ray diffraction technique. The XRD study of the compound shows that there is a change in the crystal structure of SnO2 on substitutions of CuO. The patterns of the SnO2 sample are indexed as tetragonal perovskite type with a = 7.3928 angstrom, c = 5.2879 angstrom but on substitution of CuO the structure becomes orthorhombic with lattice constant a = 21.8594 angstrom, b = 5.3200 angstrom, c = 5.1803 angstrom. Several bands due to fundamentals, overtones and combination of OH, Sn-O and Sn-O-Sn entities appear in 4000-800 cm(-1) range

Recent applications of heat capacity measurement in physicochemical investigations

This review discusses the recent experimental heat capacity measurements which have been very useful in physicochemical investigations. Areas reviewed include critical point phenomena in systems such as fluids, magnetic systems, liquid crystals, co-operative Jahn-Teller transitions, etc. The uses of C<SUB>p</SUB> measurements in the study of discrete energy levels in solids, in glasses at very low temperatures, in thin films and at high pressures are discussed. Calorimetric investigations in A-15 and other superconducting materials and applications of C<SUB>p</SUB> measurements for evaluation of thermodynamic parameters in several new classes of materials are then briefly described. Finally, examples of applications of calorimetry in areas of biophysics, biological sciences and clinical medicine are cited. Two hundred and seventy references are cited and 25 figures are used for illustration