Tujuan kajian ini ialah untuk membangunkan sistem pembelajaran makmal berasaskan komputer (MBL) bagi eksperimen fizik di peringkat pendidikan tinggi. Pembangunan sistem ini dibahagikan kepada dua bahagian; bahagian pertama melibatkan pembangunan perkakasan dan bahagian kedua ialah pembangunan perisian. Pengelog Data merupakan perkakasan utama dalam sistem ini. Perkakasan lain yang digunakan ialah penderia-penderia. Perkakasan tersebut dikawal oleh komputer. Penderia ini ditentukur selaras dengan piawaian yang ditetapkan. Data dan parameter yang diperolehi daripada penentukuran digunakan dalam perisian untuk menentukan nilai piawaian berdasarkan voltan penderia itu. Pengaturcaraan perisian menggunakan Bahasa Visual Basic 6 atau Python (Salah satu daripada sistem perisian terbuka). Beberapa eksperimen fizik disediakan menggunakan perkakasan and perisian yang telah dibangunkan. Perisian ini boleh memaparkan data pada skrin komputer melalui graph. Penggunaan perkakasan dan perisian boleh d.....

4075 hits

Phase-controlled technique through thyristors (SCR) is used instead of diodes in order to form a power converter. Output voltage of this power converter can be varied by controlling the firing angle of SCR and is used to charge the capacitor banks. Each firing angles are referred to zero-crossing point of each half of the 50 Hz AC voltage. Adjustable voltage is then used to charge the capacitor bank inside Capacitor Charging Power Supply (CCPS) for Xenon flashlamp driver. Flashlamp produced source of pulsed light that pumped the Nd:YAG laser crystal. The Nd:YAG laser usually operates at various input energies, thus requiring variable values of voltage to charge the capacitor bank. Developed phase-controlled converter can steadily controll the output voltage of CCPS from 500 V to 1000 V...

1094 hits

This paper present modeling and theoretical characterization of bimorph piezoelectric ultrasonic transducer using 2 layer of PZT-4 sandwich between 3 aluminum electrodes. Model analysis was carried out using 3-D finite element method. The transducer model is coupled with piezoelectric structure and fluid-structure problem. The transducer model has been simplified to determine the transmitting voltage response, transducer displacement, beam pattern and specific acoustic impedance. Perfectly match layer (PML) and Far Field Calculation has been implemented in the fluid-structure interaction problem to avoid artificial edge reflection and gain ability to calculate wave pressure outside the simulated region. Further validation of this model will be included in future work...

999 hits

2050 hits

This study demonstrates the wafer bonding method for performance tuning of piezoelectric Micromachined Ultrasonic Transducer (pMUT) from on-the-shelf piezoelectric disc (PZT). Polydimethylsiloxane (PDMS) and Epoxy were studied as adhesive materials. A thick bonding layer was deposited using the spin coating technique. Wafer bonding was carried out at room temperature to simulate in-situ pMUT repairing scenario. Bonding integrity is analyzed using Field Emission Scanning Electron Microscope (FESEM) images, while electrical characterization of pMUT is carried out using impedance analysis. Fabricated pMUTs have been calibrated using the pulse-echo technique in a freshwater tank. This study found that PDMS at the minimum thickness of 28 ?m is preferably compatible for in-situ wafer bonding of pMUT compared to the Epoxy. PDMS has significantly reduced device impedance at 62.4 % reduction compared to 58.9 % reduction for Epoxy. Both pMUTs were able to transmit and receive short acoustic ping.....

953 hits