78 results about "Persistent current" patented technology

Method and apparatus for providing thermal protection for actuators used in haptic feedback interface devices. An average energy in the actuator over a predetermined period of time is determined, and the maximum allowable current level in the actuator is reduced if the average energy is determined to exceed a predetermined warning energy level. The maximum allowable current level can be reduced to a sustainable current level if the average energy reaches a maximum energy level allowed, and the maximum allowable current level in the actuator can be raised if the average energy is determined to be below the predetermined warning energy level. Preferably, the maximum allowable current level is reduced smoothly as a ramp function.

Magnetic levitation methods and apparatus use arrays of vehicle magnets to provide three forces: suspension, guidance and propulsion. The magnets, which can be permanent magnets or superconducting magnets operating in the persistent current mode, have associated control coils that allow the magnets to provide a controllable attractive force to a laminated steel rail. The control coils adjust the gap between the magnets and the rails so as to be in stable equilibrium without requiring significant power dissipation in the control coils. These same magnets and steel rails also provide lateral guidance to keep the vehicle on the track and steer the vehicle on turns. The suspension control coils can provide lateral damping by means of offset magnets in the suspension arrays. Windings in transverse slots in the steel rails are excited with currents that react against the field produced by the vehicle magnets to create vehicle propulsion. The magnet size is adjusted to provide negligible cogging force even when there are as few as three winding slots per wavelength along the rail. Means are used to mitigate end effects so that a multiplicity of magnet pods can be used to support the vehicle.

The present invention relates to a radiographic imaging apparatus and a corresponding radiographic imaging method. The proposed apparatus comprises an X-ray source (20, 108) and a photon counting X-ray detector (40, 110). The X-ray source (20, 108) comprises a rotary X-ray anode (23) having a number of radial slits and a target layer provided on a surface of said rotary X-ray anode in between said radial slits for emitting X-ray radiation when hit by said electron beam. The said photon counting X-ray detector (40, 110) comprises a persistent current sensing and correction unit (70) for sensing a persistent output current in a blanking interval during which no X-ray radiation is emitted by said X-ray source and for using the sensed persistent output current to correct a detector signal in a subsequent measurement interval during which X-ray radiation is emitted by said X-ray source.

Quantum annealing may include applying and gradually removing disorder terms to qubits of a quantum processor, for example superconducting flux qubits of a superconducting quantum processor. A problem Hamiltonian may be established by applying control signals to the qubits, an evolution Hamiltonian established by applying disorder terms, and annealing by gradually removing the disorder terms. Change in persistent current in the qubits may be compensated. Multipliers may mediate coupling between various qubits and a global signal line, for example by applying respective scaling factors. Two global signal lines may be arranged in an interdigitated pattern to couple to respective qubits of a communicatively coupled pair of qubits. Pairs of qubits may be communicatively isolated and used to measure a response of one another to defined signals.

This invention provides a superconducting magnet apparatus capable of preventing or restraining the heat invading into the apparatus and reducing the refrigeration load of an external refrigerator, at the time of changeover of a switch in transiting to a persistent current mode, and capable of quick changeover operation. In the superconducting magnet apparatus of the present invention (1), in transiting to a persistent current mode, a thermal superconducting switch (41) placed in a low-temperature domain and a mechanical switch (42) placed in a mid-temperature domain are turned on. Since the mechanical switch (42) is placed in the mid-temperature domain, even if a heat load is generated through the drive mechanism (60), it is not necessary to cool the mechanical switch to an extremely low temperature. In short, heat generated at the contact point of the mechanical switch (42) and heat invasion through the drive mechanism (60) are applied not to the low-temperature domain, but to the mid-temperature domain, so that an external refrigerator can easily absorb the heat load and the capacity of the refrigerator can be reduced.

An electrically powered launcher is disclosed that can accelerate small payloads to orbital velocities. The invention uses a novel geometry to overcome limitations of other design, and allows full exploitation of existing superconducting materials.

A superconducting magnet system with a quench protection circuit includes a superconducting magnet having a plurality of series-connected superconducting coils, a persistent current switch connected in parallel with the superconducting coils, and first and second quench protection circuits connected in parallel with the superconducting coils and the persistent current switch. The first quench protection circuit includes anti-parallel diodes and parallelly connected resistive heaters and shunt resistors, and the resistive heaters and the shunt resistors are each connected in series with the diodes. The second quench protection circuit has a diode and a metal of copper connected with the diode, and a turn-on voltage of the diode in the second quench protection circuit is lower than a turn-on voltage of the diodes in the first quench protection circuit.

An apparatus includes an electrically conductive coil which produces a magnetic field when an electrical current passes therethrough; a selectively activated persistent current switch connected across the electrically conductive coil; a cryostat having the electrically conductive coil and the persistent current switch disposed therein; an energy dump; at least one sensor which detects an operating parameter of the apparatus and outputs at least one sensor signal in response thereto; and a magnet controller. The magnet controller receives the sensor signal(s) and in response thereto detects whether an operating fault (e.g. a power loss to the compressor of a cryocooler) exists in the apparatus, and when an operating fault is detected, connects the energy dump unit across the electrically conductive coil to transfer energy from the electrically conductive coil to the energy dump unit. The energy dump unit disperses the energy outside of the cryostat.

Disclosed are a second generation ReBCO high temperature superconducting wire bonding device and a bonding method using the same. The apparatus is capable of manufacturing a persistent current mode and a sufficiently long superconducting wire with nearly zero resistance at a bonding portion, compared to prior normal conductive bonding, by subjecting only superconductive layer materials to micro part melting diffusion or solid diffusion pressure welding in a state where the surfaces of ReBCO high temperature superconducting layers are in direct contact with each other, without an intermediate medium such as a solder or filler.