摘要:
Organopolysiloxane compositions having a 25° C. viscosity of at least 500 Pa·s., are continuously prepared by mixing and kneading organopolysiloxanes and fillers in a first process stage, in a kneading cascade having at least two kneading chambers arranged in series each containing two kneading tools on parallel axes, capable of being driven in corotating or counterrotating directions, the chambers connected to one another by means of openings through which material can pass in a direction transverse to the axes of the kneading tools, the first kneading chamber having a feed opening and the last kneading chamber having a discharge opening, to give raw mixtures and kneading and degassing the raw mixtures, in a second process stage at from 100° C. to 250° C. in a continuously operated double trough kneader having a discharge screw.
摘要:
Organopolysiloxane compositions having a 25° C. viscosity of at least 500 Pa·s., are continuously prepared by mixing and kneading organopolysiloxanes and fillers in a first process stage, in a kneading cascade having at least two kneading chambers arranged in series each containing two kneading tools on parallel axes, capable of being driven in corotating or counterrotating directions, the chambers connected to one another by means of openings through which material can pass in a direction transverse to the axes of the kneading tools, the first kneading chamber having a feed opening and the last kneading chamber having a discharge opening, to give raw mixtures and kneading and degassing the raw mixtures, in a second process stage at from 100° C. to 250° C. in a continuously operated double trough kneader having a discharge screw.
摘要:
In one embodiment, a magnetic resonance tomography system that has a gradient field coil system for generating a gradient field is provided. The gradient field coil system is also a main magnetic field generation system for generating a main field.
摘要:
A controller of a magnetic resonance system determines an activation signal vector based on a target field predetermined for the controller in conjunction with field characteristics of field coils known to the controller. The activation signal vector includes a respective activation signal for each field coil. The controller determines the activation signal vector such that within a predetermined examination volume of the magnetic resonance system, any deviation of an ideal field that would result if ideal coils were subjected to the activation signals of the activation signal vector from the target field is minimized. The controller determines a compensation signal vector based on the activation signal vector in conjunction with eddy current characteristics of the field coils known to the controller. The compensation signal vector is used to minimize a deviation of an actual field from the target field within the predetermined examination volume of the magnetic resonance system.
摘要:
A method for producing a gradient coil assembly for a magnetic resonance imaging system includes applying a number of primary gradient coils and a number of secondary gradient coils to a winding mandrel to form the gradient coil assembly. A control coil arrangement is associated with the winding mandrel. During an intermediate check before completion of the gradient coil assembly, at least one coupling inductance value between the control coil arrangement and at least one of the primary gradient coils and/or at least one of the secondary gradient coils is determined. An arrangement of the relevant gradient coils on the winding mandrel is corrected as a function of the at least one coupling inductance value.
摘要:
The present embodiments optimize a gradient coil structure with a gradient coil arrangement for a magnetic resonance tomography device. The gradient coil arrangement includes a carrier plate with holes. Inserts are located in the holes. The inserts are made of an electrically isolating, thermally conductive material.
摘要:
In a method and apparatus for producing a plate-type insulation support provided with an adhesive layer for a gradient coil for a magnetic resonance device, an adhesive film forming the adhesive layer is used, which has a number of openings distributed over its surface to allow the passage of air and which is applied to the insulation support.
摘要:
An arrangement for connection of gradient current feed lines in a magnetic resonance apparatus has an electrically insulating connection plate with at least one connection device. The connection device is fashioned to electrically connect a first gradient current feed line with a second gradient current feed line and is associated with a gradient coil that forms a gradient field via a supplied gradient current for a spatial direction. The supply ensues via the two gradient current feed lines connected with one another. A base plate that is fashioned for fastening the connection plate to a magnet housing of the magnetic resonance apparatus. An electrically insulating layer to damp vibrations of the connection plate is arranged between the base plate and the connection plate.
摘要:
A securing part and an unscrewing safeguard system of a gradient coil plug for an MRT that can be fixed to a gradient coil bushing include a gradient coil plug, a gradient coil bushing, a cap nut with a keyed surface and, to secure the gradient coil plug to the gradient coil bushing, a multi-tooth ring fixed to the plug so that the ring cannot rotate, and a securing part with a multi-tooth ring engagement contour that can be brought into engagement with the multi-tooth ring, and with a keyed surface engagement contour that can be brought into mating with the keyed surface of the ring.