摘要:
A superconducting magnetic levitation apparatus for driving a floating body efficiently and controllably, for producing a strong driving force, and for generating a lifting magnetic field having a uniform intensity in a running direction and producing a guidance force in a lateral direction, to stably run the floating body. The superconducting magnetic levitation apparatus includes a lifting magnet for forming a track, a floating body made of a high-T.sub.c superconductor, and a cooling device for keeping the floating body at a superconducting state. A plurality of coils are disposed on the lifting magnet, to be used as propulsion electromagnets, for generating a magnetic field necessary for running the floating body, with each of the coils being a flat, air-core coil, and with the coils being excitable by a polyphase alternating current.
摘要:
In a superconducting switching device including a switching member comprising a superconducting wire, and a magnetic field generation section for controlling superconducting-normal conducting transition caused in the switching member, the switching member comprises an oxide superconductor having a high critical temperature and having a large electric resistivity value under the normal conductive state.
摘要:
The single crystal wafer of lithium tantalate provided by the invention is characterized by the limited range of variation of the value of double refraction which should not exceed .+-.6.times.10.sup.-4 so that the value of the double refraction is given by 4.5.times.10.sup.-3 .+-.6.times.10.sup.-4. When single crystal wafers of lithium tantalate each satisfying the above requirements are used for the manufacture of SAW devices, the devices may have a very small deviation of the SAW sound velocity from the standard value and the range of variation of the SAW sound velocity within a wafer is also very small so that the SAW devices can be manufactured with greatly improved productivity and excellent quality.
摘要:
The single crystal wafer of lithium tantalate provided by the invention is characterized by the limited range of variation of the value of double refraction which should not exceed .+-.6.times.10.sup.-4 so that the value of the double refraction is given by 4.5.times.10.sup.-3 .+-.6.times.10.sup.-4. When single crystal wafers of lithium tantalate each satisfying the above requirements are used for the manufacture of SAW devices, the devices may have a very small deviation of the SAW sound velocity from the standard value and the range of variation of the SAW sound velocity within a wafer is also very small so that the SAW devices can be manufactured with greatly improved productivity and excellent quality.
摘要:
In the crystal growing of GGG (gadolinium gallium garnet) by the Czochralski technique from a melt of the oxide mixture of gadolinium and gallium, zinc is added to the oxide melt as a dopant element in a limited amount so that the danger of crack formation in the grown single crystals can be greatly decreased contributing to the improvement of the productivity. Moreover, the GGG single crystal grown with zinc doping has remarkably reduced light absorption in the wavelength region of around 300 nm responsible to the yellowish tint of the crystals.
摘要:
A superconductor composite body have a plurality of superconductor elements. Each of superconductor elements has such a volume that the superconductor element is not magnetically saturated with a magnetic flux applied to the composite body. The superconductor elements are assembled in one plane into one body in a such manner that superconductor elements are electrically coupled with each other when the superconductor elements are united with the electrically conductive non-magnetic material. The superconductor elements can be simply secured or fixed to a substrate with an adhesive or other suitable manners. When the superconductor elements have a thickness 1 mm or more, a sufficient levitation force can be generated provided that a condition of the lateral area of the assembled elements which are determined by a magnetic field and a critical current density is satisfied.
摘要:
A process for controlling an oxygen content of a non-superconductive or superconductive oxide is provided, in which a beam of particles such as ions, electrons or neutrons or an electromagnetic radiation is applied to the non-superconductive or superconductive oxide of a perovskite type such as YBa.sub.2 Cu.sub.3 O.sub.7-x, thereby increasing or reducing the oxygen content of the oxide at the sites of oxygen in the crystal lattice of the oxide. Furthermore, a superconductive device such as a superconductive magnet, superconductive power transmission wire, superconductive transformer, superconductive shield, permanent current switch and electronic element is made by utilizing the process for controlling the oxygen concentration of the superconductive oxide.
摘要:
The present invention provides a method for joining of high-temperature oxide superconductors per se or a high-temperature oxide superconductor and other conductive material through a very simple process. According to this method, the joining is carried out by using an alloy comprising 0.1%-90% by weight of at least one divalent metallic element and the balance as a brazing material and heating and melting the brazing material. The resulting joined body has a joint low in resistance. The divalent metallic element of the alloy is preferably an element of Group IIA or IIB of the Periodic Table or a transition metal.
摘要:
An improvement in the Czochralski single crystal growing of a rare earth-gallium garnet such as gadolinium gallium garnet according to which the single crystal boules of a relatively large diameter and outstandingly free from any crystal defects and inclusions are readily obtained. The improved method comprises keeping the melt of the oxide mixture formed in an iridium crucible for at least 15 hours in the molten state before crystal growing is started. It was also shown that addition of certain additive gases, e.g. water vapor, carbon dioxide and oxygen, to the gaseous atmosphere mainly composed of, for example, nitrogen, in which crystal growing was performed, in a limited proportion was effective to further improve the crystal quality and to decrease the particulate inclusions in the single crystal boules.