Determination of the refractive index of tin telluride film using Terahertz spectroscopy

Tin telluride films were prepared and characterized using terahertz time domain spectroscopy. The films were deposited on glass substrate at different temperatures inside a vacuum chamber with a pressure of 10 -6 torr,\. The substrate temperatures were 30 degrees Centigrade and 50 degrees Centigrade approximately. The real and imaginary parts of the complex refractive index were determined using the transmission spectra. The complex refractive indices were plotted against frequency that ranged from 0 THz to 0.6 THz. For films deposited at 30 degrees centigrade, the real and imaginary parts of the refractive index were found to be 4.8 and 3.5 respectively. Those deposited at 50 degrees centigrade yielded values of 5.6 and 4.0 the real and imaginary parts of the refractive index was observed on both samples at about 0.5 THz. The imaginary part of the index decreased and an increase in the real part of the refractive index was exhibited. This behavior was attributed to the increase in the materials resistivity that slows down the propagation of the electromagnetic pulse. Negative imaginary part was obtained at about 0.5 THz, which indicated the onset of compression of the electromagnetic pulse at it penetrated the sample

Hardware data compression unit

The Hardware Data Compression Unit (HDCU) is a project whose primary purpose is to provide users the capability to transparently increase the storage capacity of their disk storage devices on IBM PC/XTs and compatibles. It must be clarified that this project is not for commercial use but as a basis for further study. It is simply an add-in board which intercepts data during an I/0 (retrieval/store) operation. It performs high-speed and transparent data compression and decompression without any loss of data. Today, most data compressions are done by means of software compression programs due to its very low cost. Moreover, the compression/decompression routines of software products can sometimes be too long and not transparent to the user\u27s environment. Current articles and hand-outs regarding the latest trends in data compression were examined to come up with a transparent compression/decompression system which takes advantage of the speed provided by using a separate microprocessor-based hardware. The thesis group realized the dependency of users on commercial compression softwares for their data compression needs which in most cases, brings about some costs and overheads in time and effort. For this reason, the purpose of the thesis group in developing the system is to take advantage of the benefits brought about by microprocessor-based systems to provide users a faster data compression alternative that compresses files at a reasonable rate (30%-50%) than most commercially available compression software. Therefore, the thesis group feels that the accomplishment of the system will be an enhancement in the way computer users deal with the problem of increasing disk storage