摘要:
A plasticizer capable of fast gelling and capable of imparting storage stability on plastisols contains dialkyl terephthalate, wherein the alkyl radicals of said dialkyl terephthalate have a longest carbon chain of at least 4 carbon atoms and have a total number of carbon atoms per alkyl radical of 5.
摘要:
A process for preparing benzoic esters whose alkoxy groups have from 7 to 13 carbon atoms by reacting benzoic acid with at least one alcohol having from 7 to 13 carbon atoms, the water of reaction formed being removed during the esterification reaction by distillation, and the alcohol not converted in the esterification reaction being removed after the esterification reaction, in which the reaction takes place in the presence of a tin(II) compound as catalyst and, without treatment with a base, the catalyst and/or its derivatives is/are separated off by filtering or by centrifuging from the reaction mixture which remains after the unconverted alcohol has been separated off.
摘要:
A method is provided for analysis of a multi-dimensional structure which includes a tubular structure from two-dimensional datasets for respective pre-determined projection directions. A pair of corresponding initial projected centre points of the tubular structure is identified in two respective initial and further two-dimensional datasets. Projected edges of the tubular structure in said initial two-dimensional datasets and in said further two-dimensional dataset near the respective projected centre points are identified. A local size of the tubular strucwur is derived at the three-dimensional spatial position of the centre point of the tubular structure from said projected edges and the predetermined projection directions.
摘要:
The invention relates to a computed tomography method in which an examination zone is irradiated from two mutually offset, preferably circular trajectories. In an intermediate region the absorption distribution is reconstructed by means of measuring values from both trajectories, the weight with which the measuring values are used being larger as the distance between the voxel to be reconstructed and the relevant trajectory is smaller.
摘要:
The invention relates to a method of forming X-ray images (B) from at least two series of projection data sets (P1, P2) successively acquired along different trajectories (T1, T2), a respective 3D data set (S1, S2) being formed from each series of projection data sets (P1, P2). In order to neutralize motions of the patient between the acquisition of the individual series of projection data sets upon combination of the 3D data sets so as to form X-ray images which are as free from artefacts as possible, the invention proposes to determine a transformation rule (F) describing the location in space of the 3D data sets (S1, S2) relative to one another in such a manner that voxels are selected in a 3D data set (S1) and their location in the other 3D data set (S2) is determined by means of a suitable similarity measure, after which X-ray images (B) are formed from the 3D data sets (S1, S2) combined by means of the transformation rule (F). Consequently, it is possible to dispense with phantom members that are to be reproduced for fine adjustment of the individual 3D data sets as well as with manual fine adjustment steps. The invention also relates to an X-ray device constructed for this purpose.
摘要:
The invention relates to a computed tomography method where the examination zone is scanned by means of a conical radiation beam. The reconstruction volume can be enlarged by reconstructing the absorption of voxels in a first sub-volume by means of a first reconstruction algorithm and that of voxels in a second sub-volume by means of a second reconstruction algorithm, the assignment of the voxels to the sub-volumes being performed in such a manner that the secondary conditions for the reconstruction algorithms used for these sub-volumes are satisfied.
摘要:
Tripentyl esters of trimellitic acid, especially mixtures of triisopentyl esters of trimellitic acid comprising isomeric pentyl radicals in which more than 5 mol % of the isomeric pentyl radicals incorporated in the ester mixture are branched, have good compatibility with PVC and PVC-containing polymers and simultaneously exhibit a lesser tendency to migrate.
摘要:
A method for four dimensional reconstruction of regions exhibiting multiple phases of periodic motion includes the operation of building one or more 3-D reconstructions using a set of 2-D projections. The method further includes the operation of deriving one or more 3-D model segments from each of the one or more 3-D reconstructions, wherein a plurality of 3-D model segments are formed thereby, and wherein each of the one or more 3-D model segments is derived from a single one of the one or more 3-D model segments. The plurality of derived 3-D model segments forms a 4-D reconstruction of the region of interest.
摘要:
The present invention is directed to a limited angle tomography in combination with a filtered back projection using a special filter operator X. The filter operator X used within the present invention makes it possible to perform region of interest reconstructions although delivering high quality reconstruction images as generated by high effort SART methods. The used filter operator is purely and solely mathematically determined and defined by the spatial geometry which is used for the limited angle tomography. Without having the need to perform several iterations, the present invention directly calculates a solution, i.e. reconstructed image, equivalent to known iteratively construction methods. Although, incomplete projection data p may only be used, the present invention provides for a high image quality.