Gas hydrate model and free gas model are established, and two-phase theory (TPT) for numerical simulation of elastic wave velocity is adopted to investigate the unconsolidated deep-water sedimentary strata in Shenhu area, South China Sea. The relationships between compression wave (P wave) velocity and gas hydrate saturation, free gas saturation, and sediment porosity at site SH2 are studied, r...

accurate measurements of physical characteristics of bone are essential for diagnosis, assessment of change following treatment, and therefore, indirectly, for evaluation of new forms of therapy. this is particularly true of osteoporosis and aging skeleton, in which fractures occur easily. methods: in this study an ultrasonic system was set-up and calibrated on plexiglas tubes of variable thick...

Noninvasive evaluation of brachial artery diameter (pulsed Doppler velocimetry) and pulse wave velocity (strain gauge mechanography) was performed in 23 normal subjects and 49 patients with uncomplicated essential hypertension. Pulsatile arterial function was described in terms of derived characteristic impedance and arterial compliance. Compared with normal controls, hypertensive patients had ...

Risk factors for arterial stiffness progression have not been well characterized. We examined the relationship between arterial stiffness progression and body weight and weight gain in a group of healthy young adults. Aortic pulse-wave velocity was assessed at 2 time points approximately 2 years apart in 152 white and black adults aged 20 to 40 years, and was standardized by the time between vi...

We consider wave packets of free particles with a general energymomentum dispersion relation E(p). The spreading of the wave packet is determined by the velocity v = ∂pE. The position-velocity uncertainty relation ∆x∆v ≥ 1 2 |〈∂2 pE〉| is saturated by minimal uncertainty wave packets Φ(p) = A exp(−αE(p) + βp). In addition to the standard minimal Gaussian wave packets corresponding to the non-rel...

Direct determination of formation shear wave travel time is impossible in "slow" formations where the shear wave velocity is lower than the borehole fluid (mud) velocity. However, the Stoneley waves in these formations are very sensitive to changes in formation shear wave properties and can be used to indirectly determine the formation shear velocity, In addition, the P wave packet is highly de...

development of ultrasound technique has not been progressing for evaluating the internal quality of fruits as fast as that of processed foods. in this research for quality assessment of pear fruit (shah miveh variety) an ultrasonic measurement system was constructed to transmit and receive the ultrasonic waves. the apparatus included a pulser-receiver, a pair of 75 khz ultrasonic transducers wi...