We have built a vertical seismometer that works based on the moiré technique. One grating is attached to the suspended mass and one to the frame of the instrument. The two gratings are in relative motion, and the resulting moiré pattern magnifies this motion. The intensity of a light beam passing through the moving moiré fringes changes with time, and a light detecting syst...

In this paper altitude measurement from water surface using laser beam is presented. Research data indicate that the reflection of infrared waves from water surface is about zero and it is less than 2% for visible radiations. Phase-shift and heterodyne technique was used for the measurement, and the laser beam ( mW p nm 10 , 700 = = l ) was modulated by a sine wave having a fixed frequency....

background: it has been prover that the prevalence of experiencing job related stress is very high among the dentists. this stress can be the result of factors such as poor lightening of dental office and noise. this stress can cause emotional distress and threaten dentists’ physical health and affect the quality of their life. this study is conducted to determine dentists’ professional quality...

An atom that couples to two distinct leaky optical cavities is driven by an external optical white noise field. We describe how entanglement between the light fields sustained by two optical cavities arises in such a situation. The entanglement is maximized for intermediate values of the cavity damping rates and the intensity of the white noise field, vanishing both for small and for large valu...

the color images raise the level of educational by providing more detailed information; therefore, these images are believed to be effective in gaining a deeper understanding of the lessons. moreover, proper lighting enhances students’ learning and performance. this study aimed at assessing the impact of training color and light materials on elementary school girls’ attention and learning in pe...