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Now showing items 1-20 of 242

Oscillatory polarization potential induced at a surface by a penetrating charge

Eriksson, H. G.; Karlsson, B. R.; Wijewardena, K. A. I. L. (1985)

Considering a uniformly moving, swift charge entering a semi-infinite dielectric medium, the polarization potential at the surface is studied using a standard macroscopic and quasistatic model. The bulk dielectric function ...
Adsorption on CdTe and HgTe Surfaces

Wijewardena, K.A.I.L; Szymanski, J; Neilson, D (1988)

SYNOPISIS. To investigate the change in the surface properties of cadmium telluride when an atom is adsorbed onto a cadmium or mercury telluride when an atom is adsorbed onto a cadmium or mercury terminated (111) surface, ...
Adsorption of zinc on cadmium telluride and mercury telluride surfaces

Wijewardena, K.A.I.L; Neilson, D; Szymanski, J (1991)

Modifications of the surface properties of cadmium and mercury telluride due to the adsorption of zinc atoms are investigated. The bulk band structure is obtained by parametrizing the matrix elements in as empirical ...
Use of BBC Micro Computers in Physics

Rodrigo, B.M.A.; Sonnadara, D.U.J. (1997)

Interfacing micro computers with laboratory equipment enables the control of equipment and the analysis of experimental results to be performed effectively. In this paper we discuss how this can be done for three standard ...
An Investigation of Digital Filtering Techniques

Fernando, L.M.T.D.; Sonnadara, D.U.J.; Ranasinghe, D.N. (1997)

A study carried out on Digital Filtering Techniques covering signal digitization, the theory of digital filtering techniques, and the implementation of digital filters. The digitization covers theories related to signal ...
A Computerized Temperature Control System

Weerasinghe, W.A.T.; Sonnadara, D.U.J. (1997)

The objective of this work is to control the temperature of a furnace using an IBM compatible computer. The input data to the system are temperature sensor readings taken at constant intervals. An output signal from the ...
Comparison of FFT and Maximum Entropy Method in Sinhala Speech Recognition

Sonnadara, D.U.J.; Nanayakkara, A.; Jayananda, M.K.; Sonnadara, D.U.J. (1998)

With the recent advancement of computer technology, communicating with the computer through human voice has become a reality. There has been tremendous progress made on speech recognition in English and other European ...
Study of the performance of direction finding stations prior to the implementation of a lightning locating system in Sri Lanka

Sonnadara, D.U.J.; Fernando, I.M.K.; Jayarathne, K.P.S.C.; Ariyarathne, T.R.; Namasivayam, S.; Bandara, K.R.A. (1998)

Two direction finding stations placed in close proximity are used to monitor lightning ground flashes occurred in several thunderstorms during the monsoon season (April to July 1998). From the data collected by both ...
Virtual Instrumentation: A way to Build Low Cost Laboratory Instruments

Fernando, H.T.T.M.; Sonnadara, D.U.J. (1998)

A detailed study on building virtual instruments using Personal Computers equipped with Sound Blaster cards was carried out. A computer with a Sound Blaster card can be used to create virtual instruments with a 44.1 KHz ...
An Electronic Surveillance System for Night-Flying Birds (Bats)

Edirisinghe, C.M.; Sonnadara, D.U.J.; Yapa, V. (1998)

The construction of an electronic surveillance system that can be used to count night-flying birds passing through a 2-D window is presented. The surveillance system has been designed primarily to estimate the number of ...
Human Voice and Speech: Creating a Simple Speech Recognizer for the Sinhala Language

Sonnadara, D.U.J.; Warusawithana, M.P.; Jayananda, M.K.; Nanayakkara, A. (1998)

A Speech Recognizer which can recognize spoken words and convert them to text has numerous applications in commercial industry, in academic institutions as well as in our homes. Since the standard computer keyboard is ...
Low Cost Data Acquisition and Control Systems for Personal Computers

Jayananda, M.K.; Sonnadara, D.U.J. (1998)

A detailed study of building low cost data acquisition and equipment control systems for personal computers containing analog-to-digital (ADC) and digital-to analog (DAC) converters is carried out. Two types of boards ...
Speech Recognition - Application to the Sinhala Language

Warusawithana, M.P.; Sonnadara, D.U.J. (1998)

A simple speech recognizer was implemented for the Sinhala language by using FFT combined with Mel scaled filter banks. The accuracy of the speech recognizer depends on what words are in the vocabulary, the number of ...
Preliminary results of implementing an automated system in Sri Lanka to locate lighting ground flashes

Sonnadara, D.U.J.; Ariyaratne, T.R.; Jayaratne, K.P.S.C.; Fernando, I.M.K.; Namasivayam, S. (1998)

In this paper we report the first results of an ongoing project of implementing a lightning locating (LL) system (LLP inc., USA) consisting of four direction-finding (DF) stations. Each DF station of an LL system consists ...
The Effect of Field Leakage on the Kinetic Energy Measurements of Ions emitted in a Plasma Desorption Mass Spectrometry

Sonnadara, D.U.J.; Fernando, M.M.G.S. (1998)

The initial kick-off energy of ions emitted in Plasma Desorption Mass Spectrometers can provide useful information on the ion desorption process which is as yet not fully understood. A few groups have reported absolute as ...
Building Low Cost Virtual Instruments for Physics Research

Sonnadara, D.U.J.; Fernando, H.T.M.M. (1998)

A virtual instrument is a combination of hardware and software elements that has the functionality of a stand-alone instrument. However, unlike the traditional instruments which are designed to carry out a specific task, ...
PC Based Data Collection and Process Control Systems for Research and Industry Applications

Sonnadara, D.U.J.; Jayananda, M.K. (1998)

In Sri Lanka major research programs use donated computer controlled equipment with pre-developed hardware and software systems to collect and analyze their data. These systems are not developed further or changed even ...
Parallel Port Based Data Acquisition System for IBM or Compatible Personal Computers

Dedigama, A.R.; Sonnadara, D.U.J. (1999)

A study on building a parallel port based data acquisition system for IBM or compatible personal computers is carried out. A circuit based on an 8-bit ZN448E Analogue-to-Digital Converter (ADC) was successfully constructed ...
Some features of lightning ground flash activities observed in tropical thunderstorms

Sonnadara, D.U.J.; Weerasekara, A.B.; Fernando, I.M.K.; Lelwala, R.; Jayaratne, K.P.S.C.; Namasivayam, S.; Bandara, K.R.A.; Gomes, C.; Ariyaratna, T.R. (1999)

Some features of lightning ground flash activities in tropical thunderstorms (Sri Lanka) were studied with information provided by two lightning direction finding (DF) stations installed at Colombo (79.84 E, 6.93 N) and ...
The Role of Site Selection on Localizing Ground Flashes in an Automated Lightning Detection Network

Sonnadara, D.U.J.; Fernando, I.M.K.; Namasivayam, S.; Ariyaratne, T.R.; Jayaratne, K.P.S.C. (1999)

A Monte-Carlo simulation was used to optimize the accuracy of strike location of ground flashes depending on the selection of placement of the direction finding base-stations. A computer program was developed to reconstruct ...

Now showing items 1-20 of 242

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