A compact variable optical attenuator, covering C and L bands with over 50 dB attenuation range, is realized using a single liquid crystal cell with a tilted fused silica coating compensating the cell's small resi...A compact variable optical attenuator, covering C and L bands with over 50 dB attenuation range, is realized using a single liquid crystal cell with a tilted fused silica coating compensating the cell's small residual birefringence.展开更多
A patent pending open-loop liquid crystal based variable optical attenuator is introduced. The temperature dependent performance is compensated through electric monitoring and adjustment utilizing liquid crystal's...A patent pending open-loop liquid crystal based variable optical attenuator is introduced. The temperature dependent performance is compensated through electric monitoring and adjustment utilizing liquid crystal's opto-electronic properties.展开更多
Ultrasonic attenuation in liquid hydrogen has been messured with the pulse-echo technique as a function of temperature from 13.84K to 20.50K, at 45MHz . The results indicate that the temperature dependence of ultrason...Ultrasonic attenuation in liquid hydrogen has been messured with the pulse-echo technique as a function of temperature from 13.84K to 20.50K, at 45MHz . The results indicate that the temperature dependence of ultrasonic attenuation in liquid hydrogen is mainly determined by volume viscosity effect. Ultrasonic attenuatin due to volume viscosity is getting more and more with cooling. The ratio between volume viscous coefficient and shear viscous coefficient is from 1.4 to 4.2 within the measured temperature region.展开更多
文摘A compact variable optical attenuator, covering C and L bands with over 50 dB attenuation range, is realized using a single liquid crystal cell with a tilted fused silica coating compensating the cell's small residual birefringence.
文摘A patent pending open-loop liquid crystal based variable optical attenuator is introduced. The temperature dependent performance is compensated through electric monitoring and adjustment utilizing liquid crystal's opto-electronic properties.
文摘Ultrasonic attenuation in liquid hydrogen has been messured with the pulse-echo technique as a function of temperature from 13.84K to 20.50K, at 45MHz . The results indicate that the temperature dependence of ultrasonic attenuation in liquid hydrogen is mainly determined by volume viscosity effect. Ultrasonic attenuatin due to volume viscosity is getting more and more with cooling. The ratio between volume viscous coefficient and shear viscous coefficient is from 1.4 to 4.2 within the measured temperature region.
