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Methods for controlling the periodic molecular orientation of liquid crystals using ultrasound vibrations and estimating the orientational direction are proposed. An ultrasonic liquid crystal cell was used, consisting of a liquid crystal layer sandwiched by two glass plates fitted with piezoelectric ultrasound transducers. The transmitted light intensity distribution through the cell was measured by changing the polarization direction to investigate the orientation direction of the liquid crystal molecules. The transmitted light distributions changed periodically owing to the flexural vibration of the cell at resonance frequencies of 43.9 and 70.7 kHz. The orientational direction of the liquid crystal molecules correlated with the vibrational distribution of the glass substrates, and the molecular orientation was changed periodically by the acoustic radiation force. The interval and intensity of the transmitted light could be controlled by the driving frequency and voltage amplitude, respectively. [ABSTRACT FROM AUTHOR]

Hydroxyapatite (HAp) is compatible with bone tissue and is used mainly as a bone prosthetic material, especially as the coating of implants. Oriented HAp film is expected to be a high-quality epitaxial scaffold of the neonatal bone. To fabricate highly oriented HAp thin films via the conventional plasma process, we deposited the HAp film on a Ti coated silica glass substrate using RF magnetron sputtering in low substrate temperature conditions. The X-ray diffraction pattern of the film sample consisted of an intense (002) peak, corresponding to the highly oriented HAp. The (002) peak in XRD diagrams can be attributed either to the monoclinic phase or the hexagonal phase. Pole figure analysis showed that the (002) plane grew parallel to the surface of the substrate, without inclination. Transmission Electron Microscope analysis also showed the fabrication of aligned HAp crystallites. The selected area diffraction patterns indicated the existence of monoclinic phase. The existence of hexagonal phase could not be judged. These results indicate the uniaxial films fabricated by this technique enable to be the epitaxial scaffold of the neonatal bone. This scaffold can be expected to promote connection with the surrounding bone tissue and recovery of the dynamic characteristics of the bone. [ABSTRACT FROM AUTHOR]

Abstract  If a pipe end is faced at a piston-vibrating surface with a small gap in liquid, the liquid is suctioned into the pipe. The present ultrasonic pump is based on this phenomenon to induce flow. For a low-profile configuration, we introduce a 30-mm-diameter bending disk driven by a ring-shaped PZT element bonded on the back of the disk. The disk vibrator is softly supported by frames via O-rings at its circumference, and is worked at the fundamental resonance frequency of 19 kHz of the bending mode. A pipe is installed perpendicularly to the center of the disk vibrator with a small gap. To improve the pump performance, we seek for the optimum vibration distribution of the disk vibrator. When the thickness around the disk center becomes large, the shape of the vibration distribution near the center approaches to a piston vibrator. If the flatness of the vibration distribution is defined as the vibration amplitude just under the pipe edge divided by the vibration amplitude at the disk center, it is 92.0% for the original bending disk. The flatness of the new design became 98.1% as a result of the optimization of the thickness profile of the disk. The pump pressure became high as the flatness became large when the gap size was small enough. The maximum pump pressure of 20.6 kPa was achieved when the vibration velocity at the disk center was 1.0 m/s and the gap size was 10 μm, while the maximum flow rate of 22.5 ml/min. was obtained with the input electrical power of 3.8 W. [ABSTRACT FROM AUTHOR]