Hitachi, Ltd.

Mitsuyoshi Tsuchiya

Hideo Tsukamoto

Tsuyoshi Wakuda

Fumio Iida

Hideki Tanaka

Michiya Okada

Kazuhiro Takeuchi

Toshiyuki Shiino

Kohji Maki

Shigenori Inoue

Hiromitsu Seino

Tetsuya Kato

Tadashi Sodeyama

Shuichi Kido

Souji Kajiura

A power conversion device includes: a plurality of cascade-connection type single-phase power converters; and a central control unit that controls the plurality of the single-phase power converters, wherein each of the plurality of single-phase power converters has a single-phase power converter control unit, and the central control unit and the plurality of the single-phase power converter control units are connected via a communication means having a daisy-chain configuration, wherein the single-phase power converter control unit transmits and receives a control signal via the communication means having the daisy-chain configuration, as well as a specific pattern signal, other than a control signal frame, which can be distinguished from the control signal frame, and determines a communication error due to not receiving the specific pattern signal at the single-phase power converter control unit, or an inconsistency between the received signal and the specific pattern signal.

Power conversion device with a daisy chain configuration communication control unit

Solenoid coil arrangements for sending a high-frequency wave, receiving or sending and receiving in a measurement of an NMR signal, wherein the solenoid coil has at least two leader lines for connections to a resonance circuit. A static magnetic field compensating member is arranged outside of the leader lines and is at least one of: (a) arranged to extend a main solenoid coil in an axial direction, and not to generate a high-frequency magnetic field in a direction to cancel a high-frequency magnetic field generated by the main solenoid coil; (b) constituted by an insulant having a magnetic susceptibility of the same sign as a material of a main solenoid coil and is in an outer side in an axial direction of the main solenoid to contact with the main solenoid coil; and (c) constituted by ring-shaped members divided into a plurality of sections in a circumferential direction.

NMR solenoidal coil and NMR probe having specialized static magnetic field compensating arrangements

In NMR system, for preventing a temperature gradient which causes a decrease in S/N ratio from being created in a sample area while suppressing deterioration in homogeneity of a magnetic field, a thermal conductor having high thermal conductivity is disposed in a room-temperature shim coil. The thermal conductor is provided as a coil bobbin, the temperature of the thermal conductor being controlled by a temperature controller using a heat exchanger. Temperature control gas, which is adjusted to a temperature equal to that of the room-temperature shim coil, is fed from the downside of a sample tube, and it is possible to suppress a temperature gradient from being created in a sample area. According to the present invention, since the temperature distribution can be made to be uniform so as to avoid creating a temperature gradient in the sample area while suppressing deterioration of homogeneity in the magnetic field, the NMR spectrum is sharpened so as to improve the S/N ratio.

NMR system

An object of the present invention is to solve the bending of an NMR probe and a room temperature shim coil so that they can be positioned easily. In the NMR spectrometer including split-pair magnets and a cross bore, a high rigidity straight pipe to which an NMR probe and a room temperature shim coil are attached so as to make an integral object, is provided. The outer diameter of the straight pipe is smaller than the inner diameter of a horizontal bore into which the room temperature shim coil and the probe are inserted. After the room temperature shim coil and the NMR probe are attached to the straight pipe by bolts, respectively, the integral object is inserted into the horizontal bore (a room temperature space) of the NMR spectrometer. The room temperature shim coil and the probe may be attached to different straight pipes.

NMR spectrometer

In an NMR apparatus provided with a split type magnet, in order to position a probe at a high precision in a narrow homogeneous magnetic field space, a positioning of a center of a probe coil is first located to a proper position by inserting an NMR probe from a horizontal bore. At this position, a sample tube is inserted from a vertical bore, and an NMR signal is measured from the probe coil. An NMR signal measuring apparatus amplifies the NMR signal from the probe coil, and executes an A/D conversion so as to determine an NMR spectrum signal, and an NMR signal analyzing apparatus compares the NMR spectrum signal. A probe is set at a position where a sharpness of the spectrum is largest, that is, a magnetic field homogeneity coefficient is high, by repeating the operations mentioned above.

NMR system and probe positioning method

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.

Superconducting magnet system with quench protection circuit

A superconducting magnet system includes resistive heaters and bidirectional diodes connected in series with each other installed in a superconducting coil protection circuit, and a diode is installed in a persistent current switch protection circuit.

The present invention provides a superconductivity magnet apparatus for generating a uniform magnetic field suitable for NMR applications. The superconductivity magnet apparatus has an access port for allowing an access to the center of the magnetic field from an external position separated away from the center in a direction other than the axial direction of a split-type superconductivity electromagnet employed in the magnet apparatus. In the superconductivity magnet apparatus, a gap exists between first and second superconductivity coil blocks facing each other to form the split-type superconductivity electromagnet. To put it in detail, the access port allows an access to a measurement space at the center of the magnet by way of the gap. A configuration element of the magnet such as a coil bobbin is cut out for providing the access port. An area including a deficiency portion caused by the cutout portion or the like is filled up with a material having a relative magnetic permeability in the range 1.000 to 1.002 as an axis-symmetrical area. By using the material with a relative magnetic permeability in the range 1.000 to 1.002, the strength of an erroneously generated magnetic field can be reduced so that a magnet producing a uniform magnetic field can be provided.

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Hitachi, Japan

Mitsuyoshi Tsuchiya