Abstract: Provided is a technique capable of achieving safety and image quality at the same time in an MRI device using a transmission coil including plural channels. An SAR distribution is calculated, and an imaging parameter is determined for optimizing a radio frequency magnetic field distribution in an imaging region while suppressing a maximum value of an SAR to be equal to or smaller than a predetermined threshold value. The determined imaging parameter includes a radio frequency magnetic field parameter for specifying radio frequency pulses to be transmitted through each of the plural channels. The SAR distribution is calculated using a database that retains an electric field distribution of each of the plural channels for each subject model retained in advance.

Abstract: When an electrical characteristic of a predetermined region of a subject placed in a static magnetic field space is measured by using magnetic resonance signals measured from the region, measurement data measured by coinciding direction of a tissue structure of the subject with the direction of the static magnetic field, and measurement data measured with a direction of the tissue structure of the subject crossing the direction of the static magnetic field are used. A rotating magnetic field map of the region is created from the measurement data, and the electrical characteristic is calculated by using the rotating magnetic field map. The electrical characteristic is calculated as an electrical characteristic including anisotropy by using information about the direction of tissue structure.

Abstract: Systems and methods for magnetic resonance imaging, including adjusting spatial distribution of a rotating magnetic field. By minimizing imaging time, the B1 nonuniformity reducing effect of RF shimming is maximized for an imaging section of an arbitrary axis direction and an arbitrary position. B1 distributions are measured for only several sections of one predetermined direction, and a radio frequency magnetic field condition that maximizes the B1 non-uniformity reducing effect for an imaging section of an arbitrary direction and an arbitrary position is calculated from the B1 distribution data.

Abstract: Provided is a technique capable of achieving safety and image quality at the same time in an MRI device using a transmission coil including plural channels. An SAR distribution is calculated, and an imaging parameter is determined for optimizing a radio frequency magnetic field distribution in an imaging region while suppressing a maximum value of an SAR to be equal to or smaller than a predetermined threshold value. The determined imaging parameter includes a radio frequency magnetic field parameter for specifying radio frequency pulses to be transmitted through each of the plural channels. The SAR distribution is calculated using a database that retains an electric field distribution of each of the plural channels for each subject model retained in advance.

Abstract: B1 distribution is calculated in a short time with a high degree of precision, and a high quality image is obtained. In the RF shimming for irradiating electromagnetic waves using an RF coil having multiple channels, the absolute values of subtraction images between multiple reconstructed images are used to calculate a transmitting sensitivity distribution which is necessary for calculating inter-channel phase difference and amplitude ratio of RF pulses provided to the respective channels. Those multiple reconstructed images are obtained by executing the imaging sequence after applying a prepulse at different flip angles respectively. Assuming an image obtained with a minimum flip angle as a reference image, for instance, the subtraction images are created between the reference image and the other respective images. It is also possible that multiple subtraction images being obtained are divided by one another, and the transmitting sensitivity distribution is created on the basis of the division result.

Abstract: There is provided a technique for improving quality of images obtained with an MRI apparatus by using the geometric structures of the conventional RF transmission coil and RF reception coil and without increasing burden on patients or MRI technicians. A conductor loop of an RF reception coil disposed between a subject and an RF transmission coil is used also as a loop for magnetic field adjustment in order to shield or enhance a rotating magnetic field B1 generated by the RF transmission coil. Further, the conductor loop operated as a conductor loop for magnetic field adjustment among the conductor loops constituting the RF reception coil is driven so that inhomogeneity of the rotating magnetic field B1 is reduced.

Abstract: With an MRI apparatus using a transmission coil having multiple channels, a region desired to be diagnosed is efficiently imaged with high image quality. The MRI apparatus comprises a region setting means for setting a region in an imaging region, of which high quality image is desired to be obtained, as a first region, and an optimization means for determining at least one of amplitude and phase of a radio frequency wave transmitted to each of the multiple channels as a radio frequency magnetic field condition, and the optimization means determines the radio frequency magnetic field condition so that at least one of specific absorption ratio and signal value of a region that generates artifacts is not higher than a predetermined value defined for each, under a uniformity constraint condition that uniformity of radio frequency magnetic field distribution in the first region is not lower than a predetermined value.

Abstract: A light emitting element that includes a Ga2O3 substrate; an AlxGa1-xN buffer layer (0?×?1) formed on the Ga2O3 substrate; an n-GaN layer formed on the AlxGa1-xN buffer layer; an p-GaN layer formed on a portion of the n-GaN layer; an n-electrode formed on a portion of the n-GaN layer; and an p-electrode formed on the p-GaN layer.

Abstract: Manufacture cost and maintenance cost of RF coils of MRI devices are reduced without any limitation concerning size of the coils. By constituting an antenna device for magnetic resonance imaging devices with a cylindrical outer conductor, a looped ribbon-shaped conductor disposed inside the cylindrical outer conductor along the cylindrical surface, and a feed point for transmission and/or reception between the cylindrical conductor and the ribbon-shaped conductor, and disposing the ribbon-shaped conductor so that length thereof can be readily adjusted, there is provided an antenna device for magnetic resonance imaging devices that generates a magnetic field component perpendicular to the central axis of the cylinder at a desired resonance frequency and shows sensitivity without using capacitors and without being imposed any limitation concerning size in the diametral direction of the cylinder.

Abstract: A light emitting element that includes a Ga2O3 substrate; an AlxGa1?xN buffer layer (0?×?1) formed on the Ga2O3 substrate; an n-GaN layer formed on the AlxGa1?xN buffer layer; an p-GaN layer formed on a portion of the n-GaN layer; an n-electrode formed on a portion of the n-GaN layer; and an p-electrode formed on the p-GaN layer.

Abstract: With minimizing extension of imaging time, the B1 non-uniformity reducing effect of RF shimming is maximized for an imaging section of an arbitrary axis direction and an arbitrary position. B1 distributions are measured for only several sections of one predetermined direction, and a radio frequency magnetic field condition that maximizes the B1 non-uniformity reducing effect for an imaging section of an arbitrary direction and an arbitrary position is calculated from the B1 distribution data.

Abstract: The present invention provides a technique for maintaining a function for effectively blocking common mode noise with a simple configuration, even in the case where unbalance occurs in characteristic impedance of a coaxial cable in an MRI apparatus, and improving the performance of an RF coil. In a circuit where a balun is established by parallel connection with the coaxial cable, multiple serial resonance circuits having different resonance frequencies are connected in parallel. A value of each constitutional element of each of the serial resonance circuits is adjusted in such a manner that the frequency for blocking the common mode noise of the entire balun falls into a range between the resonance frequencies of these serial resonance circuits.

Abstract: A light emitting element has a substrate of gallium oxides and a pn-junction formed on the substrate. The substrate is of gallium oxides represented by: (AlXInYGa(1-X-Y))2O3 where 0?x?1, 0?y?1 and 0?x+y?1. The pn-junction has first conductivity type substrate, and GaN system compound semiconductor thin film of second conductivity type opposite to the first conductivity type.

Abstract: Disclosed is a polyimide foam made of an aromatic polyimide composed of a tetracarboxylic acid component, which is composed of 0 to 90% by mole of a 3,3?,4,4?-biphenyltetracarboxylic acid component and 100 to 10% by mole of a 3,3?,4,4?-benzophenone tetracarboxylic acid component and/or a 2,3,3?,4?-biphenyltetracarboxylic acid component, and a diamine component, which is composed of 50 to 97% by mole of m-phenylenediamine and 50 to 3% by mole of 4,4?-methylenedianiline. The polyimide foam can be produced easily, has uniform and fine cells, and has the mechanical properties required for practical use as a foam, such as flexibility that prevents the foam from cracking easily even when deformed and excellent cushioning properties, as well as heat resistance that can resist use at high temperatures.

Abstract: A light emitting element has a substrate of gallium oxides and a pn-junction formed on the substrate. The substrate is of gallium oxides represented by: (AlXInYGa(1-X-Y))2O3 where 0?x?1, 0?y?1 and 0?x+y?1. The pn-junction has first conductivity type substrate, and GaN system compound semiconductor thin film of second conductivity type opposite to the first conductivity type.

Abstract: The object is to propose an improved process for the production of a polyimide foam by which a large-sized polyimide foam in a state of fine and homogeneous cells can be readily obtained by easy operations and convenient steps. A melt-shaped body of a polyimide precursor obtainable by melt-treating in a closed state a powder of a polyimide precursor including at least an aromatic tetracarboxylic acid ester component and an aromatic amine component. A process for the production of a polyimide foam including the steps of melt-shaping in a closed state a powder of a polyimide precursor including at least aromatic tetracarboxylic acid ester component and an aromatic amine component to give a melt-shaped body of the polyimide precursor, and foaming the melt-shaped body of the polyimide precursor by a heat treatment.

Abstract: A light emitting element has a substrate of gallium oxides and a pn-junction formed on the substrate. The substrate is of gallium oxides represented by: (AlXInYGa(1-X-Y))2O3 where 0?x?1, 0?y?1 and 0?x+y?1. The pn-junction has first conductivity type substrate, and GaN system compound semiconductor thin film of second conductivity type opposite to the first conductivity type.

Abstract: B1 distribution is calculated in a short time with a high degree of precision, and a high quality image is obtained. In the RF shimming for irradiating electromagnetic waves using an RF coil having multiple channels, the absolute values of subtraction images between multiple reconstructed images are used to calculate a transmitting sensitivity distribution which is necessary for calculating inter-channel phase difference and amplitude ratio of RF pulses provided to the respective channels. Those multiple reconstructed images are obtained by executing the imaging sequence after applying a prepulse at different flip angles respectively. Assuming an image obtained with a minimum flip angle as a reference image, for instance, the subtraction images are created between the reference image and the other respective images. It is also possible that multiple subtraction images being obtained are divided by one another, and the transmitting sensitivity distribution is created on the basis of the division result.

Abstract: There is a provided a technology of receiving a magnetic resonance signal highly sensitively and with a uniform sensitivity distribution in an RF coil of an MRI device which is an RF coil including a switch circuit of switching a circuit configuration. The RF coil of the MRI device of the present invention includes a switch circuit of switching a circuit configuration. Also, the switch circuit switches the circuit configuration by being driven by a control signal received by wireless. For that purpose, the switch circuit includes an antenna of receiving the control signal and a conversion circuit of converting an alternating current voltage received into a direct current voltage.

Abstract: There is provided a technique for improving quality of images obtained with an MRI apparatus by using the geometric structures of the conventional RF transmission coil and RF reception coil and without increasing burden on patients or MRI technicians. A conductor loop of an RF reception coil disposed between a subject and an RF transmission coil is used also as a loop for magnetic field adjustment in order to shield or enhance a rotating magnetic field B1 generated by the RF transmission coil. Further, the conductor loop operated as a conductor loop for magnetic field adjustment among the conductor loops constituting the RF reception coil is driven so that inhomogeneity of the rotating magnetic field B1 is reduced.