Effect of Crystal-Axis Orientation on Resonance Mode of BaTiO3 Ceramics

BaTiO₃ ceramics were fabricated by sintering a mixture of fibrous and commercial powders, and the effects of crystal-axis orientation on the resonance characteristics of the poled specimens was investigated. Resonance in the radial direction was observed only for the fibrous BaTiO₃ ceramic disk. The degree of c -axis orientation of the sintered compact decreased with an increase in the initial amount of the commercial powder, and the decrease in the degree of orientation caused the appearance of the resonance in the thickness direction.     

Low-power video encoder/decoder chip set for digital VCRs

This paper describes the realization of a video encoder/decoder chip set for the consumer use digital video cassette recorder (VCR). The two chips with a 5 Mb external DRAM either encode the CCIR601 digital component video signal into the standard-definition digital VCR (DV) format or decode the DV format signal into a component video signal. The compression rate of the intraframe compression is about 1/6. The total power dissipation of the two LSI's is 142 mW at 2 V internal supply voltage, which is more than one order of magnitude smaller than the recently reported MPIEG2 (MP@ML) encoder systems. Low power was achieved primarily due to the compression scheme which is optimized for large-scale integration (LSI) implementation. The 0.5-μm 2-V CMOS standard cell library was also effective in reducing the power consumption. Each chip, fabricated in two-layer metal 0.5-μm CMOS technology, contains about 500 k transistors on 71 mm² and 79 mm² die, respectively     

Mechanism of impaired left ventricular wall motion in the diabetic heart without coronary artery disease

OBJECTIVE: To elucidate whether impairment of the myocardial free fatty acid (FFA) metabolism and small vessel abnormalities in the myocardium are etiologic or contributory factors of myocardial dysfunction in patients with NIDDM without any significant coronary artery disease. RESEARCH DESIGN AND METHODS: We performed myocardial imaging with 123I-labeled beta-methyl-p-iodophenyl pentadecanoic acid (BMIPP), a branched analog of FFA, and dipyridamole-infusion 201thallium scintigraphy (Dip) in nine patients who demonstrated left ventricular wall motion abnormalities without any significant coronary artery disease and in fifteen control cases. As an index of myocardial FFA metabolism, the heart-to-mediastinum count ratio (H/M) of BMIPP was calculated from the mean count in the regions of interest at the heart and the upper mediastinum. RESULTS: Nine patients with reduced wall motion documented by left ventriculography (LVG), (hypokinetic group) demonstrated significantly lower BMIPP uptake (2.1 +/- 0.2, mean +/- SD) than fifteen patients with normal wall motion (normokinetic group) (2.3 +/- 0.2, P < 0.05). Regional ventricular wall motion observed by LVG, regional BMIPP uptake, and regional redistribution phenomenon (RD) were evaluated for five regions of the left ventricle: anterior, septal, apical, lateral, and inferoposterior regions. Wall motion was abnormal in 24 out of 120 regions. Regional BMIPP uptake was reduced in 47 regions. RD in Dip was observed in 23 regions. In regional analysis, the existence of defect in the BMIPP image showed significant correlation with wall motion abnormality (P < 0.01), but there was no significant relationship between the RD in Dip and regional wall motion abnormality (P = 0.16). Myocardial biopsy specimens obtained from the right ventricle of 20 patients showed no pathologic changes, with the exception of two patients. CONCLUSIONS: Our findings suggest that impairment of myocardial FFA metabolism rather than small vessel abnormalities in the myocardium is responsible for modest left ventricular dysfunction in patients with diabetes.     

Molecular processes during friction of polymer films observed by thermally stimulated depolarization currents

Changes in molecular order (molecular processes) in the surface layer and the interior of polymer films during friction were studied by measuring the thermally stimulated depolarization currents of rubbed polymer films. The molecular processes are affected not only by a mechanical factor but also by an electrostatic factor produced during friction. The extent of the influence of these two factors on molecular processes depends on the structures and physical properties of the materials.     

Polymerization of methyl methacrylate in the presence of graphite

The polymerization of methyl methacrylate was carried out in the presence of graphite powder in water medium containing sulfur dioxide. The polymerization was initiated by a redox reaction between ash in graphite and HSO₃^?. Graphite powder encapusulated with polymethyl methacrylate was obtained in high yield. The mechanism of the polymerization and the capusulation are discussed.     

100 Mb/s optical-repeater experiment employing graded-index fibres

An optical-repeater error-rate experiment is described in which graded-index fibres up to 8 km long are used as a transmission medium. It is shown that 100 Mb/s modulation can be achieved with sufficiently high quality that the received signal can be regenerated for a given bit rate up to the 8 km fibre tested.