Other

Ge Medical Systems Global Technology Company, LLC

Tosoh Corporation

Masayuki Kudo

Koji Tsukuma

Hiroya Nagata

Satoshi Kondo

Tomoyuki Akiyama

Hideto Kuramochi

Mutsumi Asano

Yoshikazu Kikuchi

Shuji Takatoh

Shigetaka Hada

Nobuo Miura

Hiroyuki Yokomizo

The present invention is directed to realize an X-ray CT apparatus and a scan control method of performing contrast imaging by a helical shuttle scan with a smaller exposure amount. An X-ray CT apparatus for performing contrast imaging by repeating a reciprocating helical scan on a region in a subject repeats the helical shuttle scan (solid-line arrow) including, in shuttle (broken-line arrow) of a helical shuttle scan using an X-ray of a first X-ray dose, a helical scan using an X-ray of a second X-ray dose higher than the first X-ray dose. The start timing of the helical scan using the X-ray of the second X-ray dose is determined on the basis of a change in the CT number of a region of interest of an image captured by a helical scan using the X-ray of the first X-ray dose.

X-ray CT apparatus and scan control method

The present invention attempts to reduce an amount of a contrast medium or a patient dose and improve diagnostic efficiency. The conditions for a main scan are designated so that a first scan of scanning a subject with a tube current of a first tube current value fed to an X-ray tube will be performed in order to examine the blood flow in a subject's blood vessel into which a contrast medium is injected. Moreover, the conditions for a main scan are designated so that a second scan of scanning the subject with a tube current of a second tube current value fed to the X-ray tube will be performed in order to image the subject's blood vessel into which the contrast medium is injected. Images of the subject are constructed based on projection data items produced by scanning the subject under the sets of conditions for a main scan.

Radiography apparatus and radiography method

An abrasive molding composed of a mass of inorganic particles, said mass having pores intervening among the inorganic particles, which molding has abrasive area to be placed in frictional contact with an article to be abraded, and non-abrasive area on a abrading surface of the abrasive molding. The abrasive area has exposed pores having a diameter of not larger than 1 &mgr;m, the total area of said exposed pores having a diameter of not larger than 1 &mgr;m occupying below 15% of the total area of abrasive area, and the non-abrasive area occupies 20% to 60% of the sum of the abrasive area and the non-abrasive area.

Abrasive molding and abrasive disc provided with same

An opaque silica glass article comprising a transparent portion and an opaque portion, wherein the opaque portion has an apparent density of 1.70-2.15 g/cm and contains 5&times;10 -5&times;10 bubbles per cm , said bubbles having an average diameter of 10-100 &mgr;m; and the transparent portion has an apparent density of 2.19-2.21 g/cm and the amount of bubbles having a diameter of at least 100 &mgr;m in the transparent portion is not more than 1&times;10 per cm. The opaque silica glass article is made by a process wherein a mold is charged with a raw material for forming the opaque portion, which is a mixture comprising a silica powder with a small amount of a silicon nitride powder, and a raw material for forming the transparent portion so that the two raw materials are located in the positions corresponding to the opaque and the transparent portions, respectively, of the silica glass article to be produced; and the raw materials are heated in vacuo to be thereby vitrified.

Opaque silica glass article having transparent portion and process for producing same

An opaque silica glass article comprising a transparent portion and an opaque portion, wherein the opaque portion has an apparent density of 1.70-2.15 g/cm,and contains 5&times;10,&minus;5&times;10,bubbles per cm,, said bubbles having an averaged diameter of 10-100 &mgr;m; and the transparent portion has an apparent density of 2.19-2.21 g/cm,and the amount of bubbles having a diameter of at least 100 &mgr;m in the transparent portion is not more than 1&times;10,per cm,. The opaque silica glass article is made by a process wherein a mold is charged with a raw material for forming the opaque portion, which is a mixture comprising a silica powder with a small amount of a silicon nitride powder, and a raw material for forming the transparent portion so that the two raw materials are located in the positions corresponding to the opaque and the transparent portions, respectively, of the silica glass article to be produced; and the raw materials are heated in vacuo to be thereby vitrified.

Opaque quartz glass is provided which contains gas bubbles uniformly dispersed therein and is excellent in high-temperature viscosity and heat-insulating property. The opaque quartz glass has a defined apparent density, contains bubbles having a defined average bubble diameter in a defined amount, has a defined total bubble sectional area, generally exhibits a defined linear transmittance at a thickness of 1 mm or larger to projected light of a defined wavelength and contains nitrogen in a defined concentration. The opaque quartz glass is produced by a process comprising packing into a mold a powdery source material of powdery silica having a defined average particle diameter and powdery silicon nitride dispersed therein in a defined amount, heating the powdery source material to one of two first defined temperature ranges (both under vacuum) and further heating the source material up to a second temperature higher than the melting point and not higher than 1900.degree. C. in a vacuum or an inert gas atmosphere for vitrification and bubble formation.

Opaque quartz glass and process for production thereof

Proposed in this application is a device for adjusting ignition timing in an engine for a motor-cycle having an engine, an ignition circuit for the engine, a fluid coupling connected to the engine, a power transmission mechanism which receives driving force from the fluid coupling, and shift indicating switch which changes over in association with the power transmission mechanism to indicate a low speed drive, a high speed drive, or the neutral position, wherein the ignition timing adjusting device comprises: a plurality of ignition signal emitters, each having differing signal emission timing and producing an ignition signal output to actuate said ignition circuit when the engine is in a driven state and the vehicle is in a stopped state; and a switching element which, in accordance with change-over operation of the shift indicating switch device, controls in such a manner that any one of the output signals from the plurality of ignition signal emitters may be fed as an input into the ignition circuit.

Growing community of inventors

Tokyo, Japan

Masayuki Kudo