Abstract: Disclosed is an ultrasound probe including: a piezoelectric body that transmits and receives ultrasound; a backing that is disposed behind the piezoelectric body; and a reflector that is disposed between the piezoelectric body and the backing and that has an acoustic impedance greater than an acoustic impedance of the piezoelectric body; wherein, a thickness of the reflector is within the range of more than 0 to less than 0.05?, where ? is a wavelength of the ultrasound.

Abstract: Disclosed is an ultrasound probe including: a piezoelectric body that transmits and receives ultrasound; a backing that is disposed behind the piezoelectric body; and a reflector that is disposed between the piezoelectric body and the backing and that has an acoustic impedance greater than an acoustic impedance of the piezoelectric body; wherein, a thickness of the reflector is within the range of more than 0 to less than 0.05?, where ? is a wavelength of the ultrasound.

Abstract: An ultrasonic probe includes: a piezoelectric element that transmits and receives an ultrasonic wave; one or a plurality of acoustic matching layers disposed on a subject side of the piezoelectric element; and a conductor layer that applies a voltage to the piezoelectric element, wherein the conductor layer is disposed between the piezoelectric element and the acoustic matching layer, or between the plurality of acoustic matching layers, a magnitude of an acoustic impedance of the conductor layer is between a magnitude of an acoustic impedance of a layer disposed on one surface side of the conductor layer and a magnitude of an acoustic impedance of a layer disposed on the other surface side of the conductor layer, and the conductor layer has a Vickers hardness (Hv) of 50 or more and 600 or less.

Abstract: An ultrasonic probe includes: a piezoelectric element that transmits and receives an ultrasonic wave; one or a plurality of acoustic matching layers disposed on a subject side of the piezoelectric element; and a conductor layer that applies a voltage to the piezoelectric element, wherein the conductor layer is disposed between the piezoelectric element and the acoustic matching layer, or between the plurality of acoustic matching layers, a magnitude of an acoustic impedance of the conductor layer is between a magnitude of an acoustic impedance of a layer disposed on one surface side of the conductor layer and a magnitude of an acoustic impedance of a layer disposed on the other surface side of the conductor layer, and the conductor layer has a Vickers hardness (Hv) of 50 or more and 600 or less.

Abstract: The ultrasound probe includes a piezoelectric element including a piezoelectric composition and an electrode that applies a voltage to the piezoelectric composition. The piezoelectric composition has piezoelectric characteristics expressed by any coordinates included in a region formed by a polyhedron having a plurality of predetermined points as vertexes in Cartesian coordinates (keff, ?33S, Ec) including variables keff, ?33S and Ec.

Abstract: The ultrasound probe includes a piezoelectric element including a piezoelectric composition and an electrode that applies a voltage to the piezoelectric composition. The piezoelectric composition has piezoelectric characteristics expressed by any coordinates included in a region formed by a polyhedron having a plurality of predetermined points as vertexes in Cartesian coordinates (keff, ?33S, Ec) including variables keff, ?33S and Ec.

Abstract: The present invention is a piezoelectric composition and a piezoelectric element using the piezoelectric composition, the composition being characterized by: having a Perovskite structure represented by general formula ABO3; being represented by composition formula x(Bi0.5K0.5)TiO3-yBi(Mg0.5Ti0.5)O3-zBiFeO3, x+y+z=1 in the composition formula above; and in a triangular coordinate using x, y and z in the composition formula above, having a composition represented by a region which is surrounded by a pentagon ABCDE with apexes of point A (1, 0, 0), point B (0.7, 0.3, 0), point C (0.1, 0.3, 0.6), point D (0.1, 0.1, 0.8) and point E (0.2, 0, 0.8) and which does not include the line segment AE that connects point A (1, 0, 0) and point E (0.2, 0, 0.8).

Abstract: A group III element nitride single crystal is grown on a template immersed in a raw material liquid retained in a crucible and containing a group III material and one of an alkali metal and an alkali earth metal. The raw material liquid remaining after the growth of the single crystal is cooled and solidified, and by feeding a hydroxyl group-containing solution into the crucible, the solidified raw material is removed from around the template, and thus the group III element nitride single crystal is taken out from inside the solidified raw material. The template is disposed at a position away from the bottom of the crucible.

Abstract: The present invention is a piezoelectric composition and a piezoelectric element using the piezoelectric composition, the composition being characterized by: having a Perovskite structure represented by general formula ABO3; being represented by composition formula x(Bi0.5K0.5)TiO3-yBi(Mg0.5Ti0.5)O3-zBiFeO3, x+y+z=1 in the composition formula above; and in a triangular coordinate using x, y and z in the composition formula above, having a composition represented by a region which is surrounded by a pentagon ABCDE with apexes of point A (1, 0, 0), point B (0.7, 0.3, 0), point C (0.1, 0.3, 0.6), point D (0.1, 0.1, 0.8) and point E (0.2, 0, 0.8) and which does not include the line segment AE that connects point A (1, 0, 0) and point E (0.2, 0, 0.8).

Abstract: When a group III nitride crystal is grown in a pressurized atmosphere of a nitrogen-containing gas from a melt 50 including at least a group III element, nitrogen and an alkali metal or an alkali earth metal, a melt-holding vessel 160 that holds the above-described melt 50 is swung about two axes different in direction from each other such as an X-axis and a Y-axis.

Abstract: A method for producing a high-quality group-III element nitride crystal at a high crystal growth rate, and a group-III element nitride crystal are provided. The method includes the steps of placing a group-III element, an alkali metal, and a seed crystal of group-III element nitride in a crystal growth vessel, pressurizing and heating the crystal growth vessel in an atmosphere of nitrogen-containing gas, and causing the group-III element and nitrogen to react with each other in a melt of the group-III element, the alkali metal and the nitrogen so that a group-III element nitride crystal is grown using the seed crystal as a nucleus. A hydrocarbon having a boiling point higher than the melting point of the alkali metal is added before the pressurization and heating of the crystal growth vessel.

Abstract: A method for producing a high-quality group-III element nitride crystal at a high crystal growth rate, and a group-III element nitride crystal are provided. The method includes the steps of placing a group-III element, an alkali metal, and a seed crystal of group-III element nitride in a crystal growth vessel, pressurizing and heating the crystal growth vessel in an atmosphere of nitrogen-containing gas, and causing the group-III element and nitrogen to react with each other in a melt of the group-III element, the alkali metal and the nitrogen so that a group-III element nitride crystal is grown using the seed crystal as a nucleus. A hydrocarbon having a boiling point higher than the melting point of the alkali metal is added before the pressurization and heating of the crystal growth vessel.

Abstract: An object of the present invention is to obtain, with respect to a semiconductor light-emitting element using a group III nitride semiconductor substrate, a semiconductor light-emitting element having an excellent light extraction property by selecting a specific substrate dopant and controlling the concentration thereof. The semiconductor light-emitting element comprises a substrate composed of a group III nitride semiconductor comprising germanium (Ge) as a dopant, an n-type semiconductor layer composed of a group III nitride semiconductor formed on the substrate, an active layer composed of a group III nitride semiconductor formed on the n-type semiconductor layer, and a p-type semiconductor layer composed of a group III nitride semiconductor formed on the active layer in which the substrate has a germanium (Ge) concentration of 2×1017 to 2×1019 cm?3.

Abstract: A method for producing a high-quality group-III element nitride crystal at a high crystal growth rate, and a group-III element nitride crystal are provided. The method includes the steps of placing a group-III element, an alkali metal, and a seed crystal of group-III element nitride in a crystal growth vessel, pressurizing and heating the crystal growth vessel in an atmosphere of nitrogen-containing gas, and causing the group-III element and nitrogen to react with each other in a melt of the group-III element, the alkali metal and the nitrogen so that a group-III element nitride crystal is grown using the seed crystal as a nucleus. A hydrocarbon having a boiling point higher than the melting point of the alkali metal is added before the pressurization and heating of the crystal growth vessel.

Abstract: A method for producing a high-quality group-III element nitride crystal at a high crystal growth rate, and a group-III element nitride crystal are provided. The method includes the steps of placing a group-III element, an alkali metal, and a seed crystal of group-III element nitride in a crystal growth vessel, pressurizing and heating the crystal growth vessel in an atmosphere of nitrogen-containing gas, and causing the group-III element and nitrogen to react with each other in a melt of the group-III element, the alkali metal and the nitrogen so that a group-III element nitride crystal is grown using the seed crystal as a nucleus. A hydrocarbon having a boiling point higher than the melting point of the alkali metal is added before the pressurization and heating of the crystal growth vessel.

Abstract: The present invention provides an acoustooptic device usable even with light in the ultraviolet region, free from laser damage and optical damage, and excellent in acoustooptic performance and an optical imaging apparatus using the same. The acoustooptic device according to the present invention includes a high-frequency signal input part (65), a transducer part (64), and an acoustooptic medium (6). A high-frequency signal input from the high-frequency signal input part (65) is converted into a mechanical vibration by the transducer part (64), and an optical characteristic of the acoustooptic medium (6) varies depending on the mechanical vibration. The acoustooptic medium is formed of a Group III nitride crystal. The optical imaging apparatus according to the present invention includes a light source, an acoustooptic device, a driving circuit, and an image plane.

Abstract: When a group III nitride crystal is grown in a pressurized atmosphere of a nitrogen-containing gas from a melt 50 including at least a group III element, nitrogen and an alkali metal or an alkali earth metal, a melt-holding vessel 160 that holds the above-described melt 50 is swung about two axes different in direction from each other such as an x-axis and a Y-axis.

Abstract: An object of the present invention is to obtain, with respect to a semiconductor light-emitting element using a group III nitride semiconductor substrate, a semiconductor light-emitting element having an excellent light extraction property by selecting a specific substrate dopant and controlling the concentration thereof. The semiconductor light-emitting element comprises a substrate composed of a group III nitride semiconductor comprising germanium (Ge) as a dopant, an n-type semiconductor layer composed of a group III nitride semiconductor formed on the substrate, an active layer composed of a group III nitride semiconductor formed on the n-type semiconductor layer, and a p-type semiconductor layer composed of a group III nitride semiconductor formed on the active layer in which the substrate has a germanium (Ge) concentration of 2×1017 to 2×1019 cm?3.

Abstract: A method for producing Group-III-element nitride crystals by which an improved growth rate is obtained and large high-quality crystals can be grown in a short time, a producing apparatus used therein, and a semiconductor element obtained using the method and the apparatus are provided. The method is a method for producing Group-III-element nitride crystals that includes a crystal growth process of subjecting a material solution containing a Group III element, nitrogen, and at least one of alkali metal and alkaline-earth metal to pressurizing and heating under an atmosphere of a nitrogen-containing gas so that the nitrogen and the Group III element in the material solution react with each other to grow crystals.

Abstract: Disclosed is a method for producing a group III nitride crystal substrate. A group III nitride crystal is formed by a growth method using a flux. The group III nitride crystal substrate is heat treated at a temperature equal to or higher than the lowest temperature at which the flux contained inside the group III nitride crystal substrate through intrusion into the crystal during the crystal formation can be discharged to outside the group III nitride crystal substrate, and equal to or lower than the highest temperature at which the surface of the group III nitride crystal substrate is not decomposed.