Mohammad Sadegh Nazari

  • Citations Per Year
Learn More
OBJECTIVE Accurate delivery of torque to implant screws is critical to generate ideal preload in the screw joint and to offer protection against screw loosening. Mechanical torque-limiting devices (MTLDs) are available for this reason. In this study, the accuracy of one type of friction-style and two types of spring-style MTLDs at baseline, following(More)
Direct measurements are reported of self-heating in an AlGaN/GaN transistor using ultraviolet and visible micro-Raman. Device stack is comprised of silicon substrate, AlN nucleation, AlGaN transition, GaN buffer, and AlGaN barrier layers. Phonon shifts are used to estimate temperature rise. Ultraviolet measurements probe the current- carrying GaN near the(More)
Method: This experimental study was performed on 20 samples that were randomly selected. Two cutting designs shoulder and deep chamfer were created on dies via a standard turning machine. The diameter rim was 8mm and the height was 6 mm and the depth of cutting edge in cervical area, was 1mm. Impressions were made from dies and 10 acetone dies were prepared(More)
Visible and ultraviolet (UV) micro-Raman spectroscopies are used to study the stress in GaN integrated with diamond grown by chemical vapor deposition. Mapping of stress is accomplished across a 75-mm GaN-on-diamond wafer. UV measurements from both sides of the wafer reveal an unexpected gradient between the tensile stress from the free GaN surface (~0.86(More)
A method is described for directly measuring the temperature of a substrate in a molecular-beam epitaxy (MBE) growth system. The approach relies on the establishment of the temperature dependence of Raman-active phonons of the substrate material using independently known calibration points across the range of interest. An unknown temperature in this range(More)
  • 1