A lucency just means a dark area on the x-ray/CT as opposed to an opacity (which is a white area). I'm not sure what type of CT scan you got (i.e. with or without contrast injection), but don't jump to conclusions about it being cancer..... lucency just means a dark area on the x-ray/CT as opposed to an opacity (which is a white area). I'm not sure what type of CT scan you got (i.e. with or without contrast injection), but don't jump to conclusions about it being cancer.....
The operational details of amplifiers are buried in the field of electronics, but for audio purposes it is usually safe to say that current commercial audio amplifiers are so good that a normally operating amplifier is seldom the limitation on the fidelity of a sound reproduction system.
Our Living Language : Many people use simple ultrasound generators. Dog whistles, for example, produce tones that dogs can hear but that are too high to be heard by humans. Sound whose frequency is higher than the upper end of the normal range of human hearing (higher than about 20,000 hertz) is called ultrasound.