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This paper describes a new method for in vivo sound measurement in the reflection mode. The mean sound speed between the reflector and linear array transducer is measured using the following three parameters: time of flight, time of flight difference, and distance between two receiver elements. To detect time of flight, the system delay-line time compensator is adjusted to obtain the sharpest reflector image. This method was evaluated in vivo in human livers, specifically 26 normal, 27 cirrhotic, and 15 fatty livers. The mean sound speed between diaphragm and the transducer was obtained. The measured sound speed was significantly higher in cirrhotic livers and lower in fatty livers.

The time-course for crystalline forms of calcium phosphates was investigated by the X-ray metlrod in ti}e absence and presence of citrafe, a typical inhibitor of calcillrn phosphate formation. Dicalcium phosphate diltydrate (DCPD) was observed as a precursor without citrate, while DCPD was not ol}served in the presence of citrate, suggesting that citrate lowered the supersaturation degree of DCPD.