IMPORTANCE OF DIFFUSION PUMPING WHILE PRODUCING AMORPHOUS AND PARTIALLY CRYSTALLISED MATERIALS

It can be state that 1960 was the year when amorphous materials era began. 1989 was the year when bulk materials amorphous were first produced. Since then researchers around the World try to improve or find new correlations according to this group of materials. Sometimes instead of obtaining amorphous materials produced sample may be partially crystallised. During last research, ingots of two different alloys discussed in this work were produced with and without use of diffusion pump. Samples produced in injection method were done under the same condition for both cases of ingots. Then samples were subjected to structure analysis with the use of x-rays and were checked according to magnetic properties. Obtained results are compatible with expectations, however by meet one give promising possibility of further research.

On the Method of Calculating Diffusion Vacuum Pump Stage Pumping Parameters

At present, steam jet vacuum pumps are widely used in various fields of science and technology due to a number of advantages, e.g., reliability, relative simplicity of design, and manufacturability, over other pumping means. The paper analyzes the existing mathematical models of working processes, methods for calculating the pumping parameters of steam-jet vacuum pumps. The problem of improving these methods, which are used in the design, is still urgent. The study attempts to further develop the models in order to increase their practical significance for the pumps design: in particular, the processes of pumping by the first stages of a diffusion pump are considered, since it is they that determine the efficiency of the pump as a whole. Analytical dependences for calculating the main pumping parameters of widely used diffusion vacuum pumps are presented. The obtained equations are a certain clarifying correction of the known provisions on this topic. Findings of research are of practical importance for the design of modern steam-jet vacuum pumps

The Effect of Thickness of Aluminium Films on Optical Reflectance

In Uganda and Africa at large, up to 90% of the total energy used for food preparation and water pasteurization is from fossil fuels particularly firewood and kerosene which pollute the environment, yet there is abundant solar energy throughout the year, which could also be used. Uganda is abundantly rich in clay minerals such as ball clay, kaolin, feldspar, and quartz from which ceramic substrates were developed. Aluminium films of different thicknesses were deposited on different substrates in the diffusion pump microprocessor vacuum coater (Edwards AUTO 306). The optical reflectance of the aluminium films was obtained using a spectrophotometer (SolidSpec-3700/DUV-UV-VIS-NIR) at various wave lengths. The analysis of the results of the study revealed that the optical reflectance of the aluminium films was above 50% and increased with increasing film thickness and wavelength. Thus, this method can be used to produce reflector systems in the technology of solar cooking and other appliances which use solar energy.

Synthesis and Characterization of Fluorinated Alkyl Substituted Disiloxane

Alkyl substituted disiloxanes demonstrated promising applications as high performance hydraulic oil, diffusion pump oil, etc. In this study, fluorinated alkyl substituted disiloxane was synthesized via Grignard reaction followed by condensation reaction. Its chemical structure was verified by FTIR and NMR. Measurement results showed that this silicon oil exhibited good high temperature performance, oxidation resistance and rust resistance.

Design on Ultrahigh Vacuum System with Titanium Pump

In order to meet the further requirements that study diamond-like carbon (DLC) films as rigid protective coating, a three-stage ultrahigh vacuum system composed of rotary vane pump and diffusion pump in parallel with TSP ( titanium sublimation pump) was designed mainly for getting limiting vacuum of 1.0×10-6Pa within 30 minutes in the vacuum chamber of about 0.23m3. The chamber is a horizontal cylinder supported by a saddle-shaped bracket and it has been proved to satisfy the requirements of strength and stiffness, it can be easy to get ultrahigh vacuum by TSP. Initiation pressure of the TSP was set to 10-3Pa vacuum after optimization analysis and the diffusion pump simultaneously was closed for the proper use. The system can be used as deposition equipment with the assistance of high and low vacuum measuring instruments and other accessories.