摘要:
In a method and magnetic resonance tomography apparatus for triggered implementation of a measurement (composed of partial measurements) in the magnetic resonance tomography apparatus, at least one image data set is determined from the data acquired within the scope of the partial measurements, and for triggering a reference point of the movement phase of the movement is used. The image data set is acquired in segments; the reference point is detected by a control device independent of a partial measurement, and the partial measurement following the detected reference point is conducted depending on the independently detected reference point. The wait time that specifies the interval from the end of the partial measurement to the beginning of the next partial measurement is adapted depending on the point in time of detection.
摘要:
A set of image-space data is reconstructed from a set of k-space data. The set of image-space data is generated by minimizing a cost functional by an iterative non-linear conjugate gradient process. The iterative process may be accelerated by introducing k-space weighting to the cost functional. With proper choice of k-space weighting, a block-Toeplitz matrix is generated which permits use of Fast Fourier Transform techniques. An image is rendered from the set of image-space data.
摘要:
A set of image-space data is reconstructed from a set of k-space data. The set of image-space data is generated by minimizing a cost functional by an iterative non-linear conjugate gradient process. The iterative process may be accelerated by introducing k-space weighting to the cost functional. With proper choice of k-space weighting, a block-Toeplitz matrix is generated which permits use of Fast Fourier Transform techniques. An image is rendered from the set of image-space data.
摘要:
In a method for imaging a periodically-moving subject region of a subject, an overview image data set is initially obtained that maps a movement of the subject region, at least two positions that the subject region assumes at corresponding points in time are marked in the overview image, further positions of the subject region at further points in time are interpolated from the marked positions and further points in time, and a subsequent diagnostic imaging of the moving subject region is implemented using the marked and interpolated positions.
摘要:
The present invention relates to new cross-linking agents and thermosetting paints, which lead to improved properties such as scratch resistance of cured thermosetting paints or exhibit good solubility.
摘要:
The present invention provides methods and apparatus for determining flow velocity within a formation utilizing nuclear magnetic resonance (NMR) techniques in which the shape of the resonance region is restricted so that sensitivity to radial flow or vertical flow is obtained (or both when more than one NMR tool is used). Flow velocity using these NMR tools is determined using decay amplitude, frequency displacement or stimulated echoes (where the spins are stored along the magnetic field instead of the transverse plane to exploit echo decays and frequency displacements) based on the application of adiabatic pulses. Based on the described NMR measurement of flow velocity, additional wellbore parameters may be obtained such as a direct measurement of permeability, an assessment of drilling damage to the wellbore, formation pressure, invasion rate of the mud filtrate or the migration of fine mud particles during sampling operations.
摘要:
A method and an apparatus for obtaining NMR measurements are disclosed. An NMR measurement apparatus, the measured sample, or both elements may be subjected to motion during the measurement. The envelope of an RF carrier signal is modulated according to an envelope to generate a first sequence of RF pulses. The envelope, the phase of the RF signal, and/or a static magnetic field may be varied during the radiation of the first sequence to substantially saturate a first region of the sample. The first sequence may include additional RF refocusing pulses that, when coupled with movement of the NMR measurement apparatus or sample, may also be used to substantially saturate the first region. A second sequence of RF pulses is radiated to establish a resonance region within the first region and measure an attribute of the sample.
摘要:
A process for producing surface-sealed hollow glass containers, the hollow glass containers are, in the production process in the region of the exit from the annealing lehr which is located downstream of a machine for producing hollow glass containers, coated by means of a water-based cold end coating composition comprising at least the following components: I. a trialkoxysilane, a dialkoxysilane and/or a tetralkoxysilane or their hydrolysis and/or condensation products and also II. a water-soluble or water-dispersible mixture of a polyol and a crosslinker, wherein the applied layer of the cold end coating composition is subsequently subjected to a crosslinking step. The hollow glass containers produced in this way have an improved strength.
摘要:
The present invention provides methods for determining the bound fluid volume (BFV) of a formation utilizing nuclear magnetic resonance (NMR) techniques in which less than full polarization occurs and in which less than a complete NMR distribution is acquired. The effect of the polarizing static magnetic field is shortened in time by applying a shortened wait time between NMR measurements so that only the bound fluid of the formation is polarized. The shortened wait time is effectuated by early application of the oscillating magnetic field to the formation which, in conjunction with a limited number of refocusing pulses, induces signals in the formation that are measured by the NMR tool. The peak amplitude of these signals corresponds to the BFV. The present invention provides information so that a partial polarization calculation curve in T2 lies almost equally between an empirical tapered cutoff curve and a theoretical tapered cutoff curve. Moreover, because no T2 information must be acquired, the method is especially suited for logging-while-drilling operations, where the drill string moves uncontrollably during the NMR measurement.
摘要:
To generate an MR image, acquired MR data are entered into k-space on multiple uniform trajectories in k-space within a predetermined time period. The trajectories are acquired chronologically in a predetermined order before a predetermined point in time, and in a different order after the point in time. The i-th trajectory after the point in time in the different order is adjacent to the (n−i+1)-th trajectory in the predetermined order (n is the number of trajectories acquired before and after the point in time). Two trajectories are adjacent if a distance between them is less than a predetermined threshold. Except for the (n−i+1)-th trajectory, none of the trajectories acquired before the point in time has a distance from the i-th trajectory that is less than the threshold. The predetermined time period is set to be at a middle of a time period after an RF excitation pulse, such that a contrast change within the predetermined time period proceeds as linearly as possible over time.