Abstract: A thermoelectric power generation apparatus includes: a higher-temperature side heat conductor; a lower-temperature side heat conductor disposed at a distance from the higher-temperature side heat conductor; a thermoelectric power generation module including a higher-temperature side electrode that is in thermal contact with the higher-temperature side heat conductor, and a lower-temperature side electrode that is in thermal contact with the lower-temperature side heat conductor; a heat insulating member disposed between the higher-temperature side heat conductor and the lower-temperature side heat conductor, the heat insulating member accommodating the thermoelectric power generation module; and an integrating member provided separately from the heat insulating member. The higher-temperature side heat conductor and the lower-temperature side heat conductor are integrated with each other by the integrating member with the heat insulating member interposed therebetween.

Abstract: An optical sensor is provided, in which members forming an optical path can be reliably supported without blocking the optical path extending from a light source to a light receiver. An optical sensor includes a light source configured to emit light, and a light receiver configured to receive the light emitted from the light source. An optical path extending from the light source to the light receiver extends through an oil infiltrating space into which oil infiltrates. The optical sensor further includes: a substrate on which the light source is mounted; a substrate on which the light receiver is mounted; a fixing member including an accommodation space in which the substrates are accommodated; and a sealing resin contained in the accommodation space and sealing the substrate.

Abstract: Provided is a tunnel boring machine that can detect a wear condition of a disc cutter with a highly reliable configuration. The tunnel boring machine includes a measurement device. The measurement device is disposed behind the disc cutter mounted on a cutter head. The measurement device has a function as an acquisition unit that acquires cutting edge position data indicating a position of a cutting edge part of a cutter ring in the disc cutter. The tunnel boring machine further includes a DC discrimination unit that discriminates which one of a plurality of disc cutters is the disc cutter the cutting edge position data of which is acquired by the measurement device and a wear amount calculator that calculates a wear amount of the cutting edge part of the discriminated disc cutter.

Abstract: The object of the present invention is to realize the piezoelectric ceramics which, even when used as high frequency elements utilizing third harmonics wave of thickness longitudinal vibration, are small in temperature coefficient of resonant frequency and high in mechanical Q value and easy to correspond to the trend toward miniaturization and low voltage driving. When the piezoelectric ceramics with lead titanate as its main component are manufactured in order to achieve this object, it was decided that the piezoelectric ceramics be manufactured by the manufacturing method, wherein a heat treatment is performed between a firing process and a polarization process in the atmosphere of oxygen partial pressure less than the oxygen partial pressure of the atmospheric pressure at temperatures more than 500.degree. C. and not more than the firing temperatures.

Abstract: Provided is a piezoelectric ceramic which achieves a high density, good temperature characteristics and a high Curie temperature, which can fully prevent (a) a decrease in Qmax (Qmax refers to a tan.theta.max when the maximum value of phase angles of third harmonic is a .theta.max), (b) a decrease in q (dynamic range of resonance frequency), (c) an increase in a fundamental wave and (d) the occurrence of a spurious mode in the vicinity of third harmonic, caused by downsizing, and which can materialize a small-sized high-performance piezoelectric element, the piezoelectric ceramic having a composition of the general formula,(Pb.sub.a-k-y-z Sr.sub.x Ln.sub.y Bi.sub.z)(Ti.sub.1-b-c Mn.sub.b Me.sub.c)O.sub.3wherein Ln is at least one element selected from the group consisting of La, Ce and Pr, Me is at least one element selected from the group consisting of Nb, Sb and Ta, and x, y, z, a, b and c represent molar ratios, the composition satisfying 0.ltoreq.x.ltoreq.0.2, 0<y.ltoreq.0.1, 0.001.ltoreq.z.ltoreq.0.

Abstract: A lead-oxide-free piezoelectric ceramic composition having an electromechanical coupling coefficient greater than a predetermined value and having a Curie point of at least 500.degree. C., whose main component is a two-component-based solid solution of the formula of (1-x)Bi.sub.a Ti.sub.b Nb.sub.c O.sub.9 -xNa.sub.p Bi.sub.q Nb.sub.r O.sub.9, and which has a bismuth layer structure in the range of 0<x<1,the solid solution of the above formula satisfying 2.4<(1-x)a+xq<3.1,0<b<1.1,0.9<(1-x)c+xr<2.1, and0<p<0.6.

Abstract: One object of the present invention is to provide a lead-free piezoelectric material excellent in piezoelectric characteristics and superior from the viewpoints of prevention of environmental pollution, protection of environments and ecology. To achieve the object, a piezoelectric ceramic composition is constructed from a piezoelectric ceramic composition within a region in case of being represented by the formula:x[Bi.sub.1/2 Na.sub.1/2 ]TiO.sub.3 -y[MeNbO.sub.3 ]-(z/2)[Bi.sub.2 O.sub.3.Sc.sub.2 O.sub.3 ](wherein Me is K or Na)wherein X, y and z satisfy the following conditions:x+y+z=1, 0<x<1, 0.ltoreq.y<1, 0<z<0.5.