Hitachi, Ltd.

Hitachi Vehicle Energy, Ltd.

Yoshimi Yanai

Takahiko Kato

Hiroshi Satoh

Takanobu Mori

Akira Okayama

Michiya Okada

Yutaka Fukui

Toyotaka Yuasa

Kazuhide Tanaka

Takefumi Okumura

Tetsuo Kashimura

Toshiya Doi

Toshimi Matsumoto

Masanori Yoshikawa

Takahiro Yamaki

Tadaoki Morimoto

Takaaki Suzuki

Tomoichi Kamo

Nobuyuki Iizuka

Shinpei Matsuda

Kunihiro Maeda

Akira Yoshinari

Kazutoshi Higashiyama

Hideyo Kodama

Yasuo Kondo

Eiji Seki

Kimihiko Akahori

Yoshiteru Chiba

Teruo Kumagai

Atsuko Soeta

Yoshiaki Kumashiro

Tsuneyuki Kanai

Shigeo Hattri

In a charging/discharging unit provided with: a lithium secondary battery, a voltage detecting sensor for detecting a voltage and a current detecting sensor; the charging/discharging control unit is further provided with a controller, and a discharging element for performing a constant voltage discharging operation of 3 V. A voltage, V, of the battery when a discharging operation is terminated (t=0) is measured by the voltage detecting sensor. If V&#x2266;3.6 V, within a rest time during which the battery is not charged/discharged until a next charging operation, a voltage, V, of the battery when a time, t, has elapsed is measured by the voltage detecting sensor. If this voltage charge is in a range of V-V&#x2267;0.2 V, then the constant voltage discharging operation of 3 V is carried out for a time duration longer than or equal to 1 hour.

Charging/discharging control unit for lithium secondary battery

The present invention provides a lithium secondary battery which has improved safety, mainly coming from use of an electrolyte solution which is not inflammable at room temperature (20&#xb0; C.), while not deteriorating output characteristics at low temperatures and room temperature or output maintenance characteristics after storage at high temperature (50&#xb0; C.). The lithium secondary battery of the present invention, encased in a container, is provided with a cathode and an anode, both capable of storing/releasing lithium ions, a separator which separates these electrodes from each other, and an electrolyte solution containing a cyclic carbonate and a linear carbonate as solvents and a compound such as VC at composition ratios of 18.0 to 30.0%, 74.0 to 81.9% and 0.1 to 1.0%, respectively, based on the whole solvents, all percentages by volume.

Lithium secondary battery

This invention provides an oxide-type superconducting flat wire having a critical current density of at least 1,000 A/cm.sup.2, which comprises a Y--Ba--Cu oxide layer having a superconducting property and a silver layer surrounding the oxide layer and has so flat a cross section vertical to the longitudinal direction of the wire that the upper and lower lines between the oxide layer and the silver layers appearing on the cross section having a zone over they are parallel to each other, the thickness of the oxide layer being cold rolled in the range of 0.35 to 0.75 based on the whole thickness of the wire, the whole thickness being 0.2 mm or less, and the metal layer being deformable to follow the shrink deformation of the oxide layer when heat treated to be sintered, but rigid when used. This flat wire is produced by filling a silver-made tube with a Y--Ba--Cu oxide powder having a superconducting property, drawing the tube into a rod wire having a round cross section, then cold rolling the rod wire in the flat wire so that (t.sub.i -t)/t.sub.i .times.100 is equal to or greater than 90%, wherein t.sub.i is the whole thickness of the cross section of the rod wire before the cold rolling and t is the whole thickness of the cold-rolled flat wire, and then heat treating the flat wire to sinter the superconducting oxide.

Superconducting wire and method of producing the same

A shape memory alloy pipe coupling in the present invention for joining two pipes, the pipe coupling comprising a tube of a shape memory alloy, and a cover of stainless steel having a sufficient thickness and having high corrosion resistance for covering the tube. The shape memory alloy is enclosed by the cover of high corrosion-resistant stainless steel, by which high-temperature water can be prevented from making the shape memory alloy brittle and from corroding and damaging the shape memory alloy particularly through galvanic corrosion even in the case where such high-temperature water exists in the inside or outside of the pipes.

Shape memory alloy pipe coupling and underwater pipes

A method of producing a high-temperature oxide superconducting material, which comprises the steps of (a) preparing a material corresponding to an oxide superconductor of the perovskite type structure consisting essentially of a first member selected from the group consisting yttrium, lanthanoids, thallium and bismuth; at least one alkaline earth metal; copper; and oxygen and (b) heating the material in the presence of an alkali metal selected from the group consisting of potassium, sodium, rubidium and cesium to a temperature around the melting point of the alkali metal or to a higher temperature for a time sufficient to effect grain growth in the superconductor material, thereby to produce the superconductor containing the alkali metal in an amount not larger than 4 mole % based on the first member.

Oxide high-temperature superconducting material, method of preparing

The present invention provides a shaped superconductor article such as wire, tape or disk, comprising an oxide superconductor phase and a metal phase in a monolayered or multilayered form, the metal phase comprising a copper, iron, nickel or titanium base alloy containing 1 to 10% by weight of aluminum and having an oxygen-impermeable oxide film formed thereon, preventing the diffusion of oxygen from the oxide superconductor phase to the metal phase.

Ceramic superconductor article

An electric rotary machine (for example, a dynamoelectric machine) having a superconducting rotor is disclosed in which an outer shielding member for protecting a superconducting field winding from the influence of the magnetic flux from the stator side and for interrupting heat radiated from the normal temperature side is made of a nickel alloy containing not more than 0.3% carbon, not more than 1% silicon, not more than 2% manganese, not more than 1.5% titanium, from 2 to 8% aluminum, from 8 to 40% copper, and not less than 55% nickel for the balance by weight. The nickel alloy has a structure that a .gamma.'-phase precipitation is formed by aging in an austenitic matrix, and is non-magnetic at 20.degree. C.

Electric rotary machine having superconducting rotor

A gas turbine combustor defines a combustion chamber for combustion of injected fuel and for introduction of the resultant hot combustion gas to nozzles of a gas turbine. The combustor has parts subjected to hot combustion gas during operation of the turbine, such as a cap connected to a fuel injection nozzle, a liner connected to the cap, and a transition piece connected to the liner. These parts subjected to the hot combustion gas are made from an alloy having a composition consisting essentially of 0.02 to 0.2 wt % of C, 15 to 30 wt % of Cr and 10 to 25 wt % of W.

Gas turbine combustor

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Hitachi, Japan

Yoshimi Yanai