97 results about "Spiral trajectory" patented technology

High speed removal of material from a specimen employs a beam positioner for directing a laser beam axis along various circular and spiral laser tool patterns. A preferred method of material removal entails causing relative movement between the axis of the beam and the specimen, directing the beam axis at an entry segment acceleration and along an entry trajectory to an entry position within the specimen at which laser beam pulse emissions are initiated, moving the beam axis at a circular perimeter acceleration within the specimen to remove material along a circular segment of the specimen, and setting the entry segment acceleration to less than twice the circular perimeter acceleration.

The present invention is directed to a turbine comprising a plurality of blades that rotate in a single direction when exposed to fluid flow, wherein the plurality of blades are joined to the central shaft by a plurality of radial spokes disposed substantially perpendicular to the central shaft such that the rotating plurality of blades causes the shaft to rotate. The plurality of blades has a uniform airfoil-shaped cross section, where the airfoil cross section presents a non-zero angle of attack to the current. The plurality of blades wind in a spiral trajectory, rotating around the central shaft and having a variable radius along the length of the central shaft such that a distance measured from the plurality of blades to the center shaft is greater near the center of the turbine than at either end.

The method serves to place a space vehicle, such as a satellite, on a target orbit such as the orbit adapted to normal operation of the space vehicle and starting from an elliptical initial orbit that is significantly different from, and in particular more eccentric than the target orbit. The space vehicle is caused to describe a spiral trajectory made up of a plurality of intermediate orbits while a set of high specific impulse thrusters mounted on the space vehicle are fired continuously and without interruption, thereby causing the spiral trajectory to vary so that on each successive revolution, at least during a first stage of the maneuver, perigee altitude increases, apogee altitude varies in a desired direction, and any difference in inclination between the intermediate orbit and the target orbit is decreased, after which, at least during a second stage of the maneuver, changes in perigee altitude and in apogee altitude are controlled individually in predetermined constant directions, while any difference in inclination between the intermediate orbit and the target orbit continues to be reduced until the apogee altitude, the perigee altitude, and the orbital inclination of an intermediate orbit of the space vehicle have substantially the values of the target orbit.

Spiral imaging has recently gained acceptance for rapid MR data acquisition. One of the main disadvantages of spiral imaging, however, is blurring artifacts due to off-resonance effects. Dixon techniques have been developed as methods of water-fat signal decomposition in rectilinear sampling schemes, and they can produce unequivocal water-fat signal decomposition even in the presence of B₀ inhomogeneity. Three-point and two-point Dixon techniques can be extended to conventional spiral and variable-density spiral data acquisitions for unambiguous water-fat decomposition with off-resonance blurring correction. In the spiral three-point Dixon technique, water-fat signal decomposition and image deblurring are performed based on the frequency maps that are directly derived from the acquired images. In the spiral two-point Dixon technique, several predetermined frequencies are tested to create a frequency map. The techniques can achieve more effective and more uniform fat signal suppression when compared to the conventional spiral acquisition method with SPSP pulses.

In a method for distortion correction in spiral magnetic resonance imaging, a first MR data set is acquired by scanning raw data space along a spiral trajectory beginning at a first point. A first complex MR image is determined from the first MR data set, which includes first phase information for image points of the first MR image. A second MR data set is acquired by scanning raw data space along the spiral trajectory beginning at a second point that differs from the first point. A second complex MR image is determined from the second MR data set, which includes second phase information for image points of the second MR image. A geometric distortion for image points of the first or second MR image is determined from the first and second phase information, for example with a PLACE method.

The invention discloses a flounder-type underwater glider. An electronic cabin comprises a pressure-resisting cabin, a gravity and gravity center adjustment mechanism, a control system and a lithium battery unit. The inside of the pressure-resist cabin is partitioned into a central area, a middle circular area and an outer circular area. The lithium battery unit is arranged in the middle circular area. The control system includes an overwater control system and an underwater control system which are connected in a wireless manner. The underwater control system and the electronic part of surveying equipment are arranged in the middle circular area uniformly. The gravity and gravity center adjustment mechanism comprises four water bag pump units in same structure, and the four water bag pump units are distributed in the outer circular area symmetrically. The flounder-type underwater glider has the advantages of low cost, low noise, high endurance and high flexibility; the gravity and posture of the glider can be adjusted to realize zigzag or spiral trajectory through controlling the four water bag pump units distributed symmetrically. The flounder-type underwater glider can carry a plurality of underwater scientific-investigation and survey devices simultaneously, continuous data collection in extensive sea areas can be completed automatically, and the data can be transmitted back in real time.

A novel instrument and method for TOF/TOF mass spectrometry is offered. A spiral trajectory time-of-flight mass spectrometer satisfies the spatial focusing conditions for the direction of flight and a direction orthogonal to the direction of flight whenever ions make a turn in the spiral trajectory. An ion gate for selecting precursor ions is placed in the spiral trajectory of the spiral trajectory time-of-flight mass spectrometer. Electric sectors are placed downstream of the ion gate.

An MRI image from spiral trajectory scanning is arranged as complementary subsets of values in time-sampled k-space. These values are Fourier transformed to produce a spatial domain image. While holding the patient stationary, the contrast information is updated at the central portion of k-space, and the peripheral portion of k-space data can be filled during the whole image acquisition. The contrast information is combined with the peripheral portion of k-space (contributing to image resolution) to construct a full k-space data and to generate a spatial image. The technique is useful for providing short time interval sampling when analyzing the take-up and fade-away of a contrast agent over time.

The present invention relates to a cooling apparatus for an electronic device. In the present invention, a coolant passing through a condenser 10 is introduced into and s filled in a compensator 15. The coolant passing through the compensator 15 is introduced into a vaporizer 20 and vaporized through heat exchange with an auxiliary heat source H2 provided outside of the vaporizer. In addition, a vaporizing unit 22 made of a porous material is provided in the vaporizer 20. The coolant passing through the vaporizer 20 and a liquid coolant supplied from the condenser 10 are mixed in a vortex generating unit 30 to form a coolant spray, and the coolant spray moves along a spiral trajectory to be formed into a vortex. Meanwhile, the coolant spray of a vortex is injected to be in close contact with the inner wall of an evaporator 50 to be heat-exchanged with a main heat source H1 positioned outside of the evaporator, thereby cooling the main heat source H1.

According to the present invention as mentioned above, the main heat source adjacent to the evaporator is heat-exchanged with the coolant more actively to thereby improve the cooling performance of the electronic device. Also, a pressure loss of the coolant spouted from the venturi tube is further reduced.

The invention relates to a construction method of a time-varying dynamic model for high-feed turning of external thread members; the method comprises the steps of I, using, based on the Rayleigh beam vibration theory, a nose track spiral line equation as an integration object to solve a workpiece strain energy and kinetic energy equation for a tool that performs cutting along the nose spiral track; II, considering, based on an established tool instant cutting force model, the impact of 'quasi-regeneration effect' upon instant cutting force for turning a large-pitch thread member so as to correct the existing instant cutting force model and perform numerical solution; III, describing boundary conditions of thread member turning through a vibration mode function, and performing solving; IV, establishing and solving a workpiece vibration model according to the virtual work principle and the method of separation of variables. The large-pitch external thread member vibration equation established herein is capable of predicting a sharply varying position of a workpiece upon vibration and displacement, and can assist in adjusting and optimizing parameters of a machining process for large-pitch thread members.

A modified projection on convex sets (POCS) algorithm and method for partial k-space reconstruction using low resolution phase maps for scaling full sets of reconstructed k-space data. The algorithm can be used with partial k-space trajectories in which the trajectories share a common point such as the origin of k-space, including variable-density spiral trajectories, projection reconstruction trajectories with a semicircle region acquisition, and projection reconstruction trajectories with every other spike acquired.

The present invention is directed to a method of manufacturing a turbine blade. The method comprises selecting a pipe having a specific inner diameter, length and wall thickness, cutting the pipe along a spiral trajectory to produce a coil, securing the coil, and shaping the coil to create a uniform hydrofoil cross section along the length of the coil.

The invention discloses a method for enhancing the transverse strength of an FRP (fiber reinforced plastics) pultruded profile by utilizing a weaving technology, relates to a method for enhancing an FRP material, and aims to solve the problem of low transverse strength of the FRP pultruded profile prepared by a conventional method. The method comprises the following steps of 1, preparing a resin substrate; 2, drying and arranging fibers; 3, wetting the fibers; 4, pre-forming longitudinal fibers; 5, weaving a surface layer; 6, pre-forming a woven layer; and 7, performing solidification shaping. The method for enhancing the transverse strength of the FRP pultruded profile by utilizing the weaving technology has the advantages that the transverse tensile strength of the prepared FRP pultruded profile reaches 50 to 90MPa, and is improved by 20 to 50 percent compared with that of the FRP pultruded profile prepared by the conventional method; the longitudinal tensile strength of the FRP pultruded profile reaches 600 to 900MPa; the surface layer fibers of the pultruded profile form a spiral trajectory, and are interwoven into a seamless whole.

The invention provides an in-place precision measurement method for a three-dimensional shape error of an aspheric grinding circular arc diamond grinding wheel. The in-place precision measurement method comprises the steps that (1) height data of all points on the surface of the grinding wheel are spirally and continuously scanned and measured; (2) the data are subjected to interpolation fitting treatment according to a spiral trajectory model, a three-dimensional geometrical morphology matrix on the surface of the grinding wheel is obtained, and least square circular arc fitting is conducted, so that the circular arc radius, the circular arc center coordinate and the circular arc center deviation of the grinding wheel are obtained; (3) an average three-dimensional geometrical morphology matrix on the surface of the grinding wheel is established and subtracted from the morphology matrix, and a three-dimensional error distribution matrix, a circular arc degree error and a radial run-out error are obtained; and (4) outer circumference height data of the grinding wheel are measured, and the basic part radius of the grinding wheel is obtained through least square circular arc fitting. According to the in-place precision measurement method for the three-dimensional shape error of the aspheric grinding circular arc diamond grinding wheel, efficient precision non-contact measurement of all the important geometrical parameters of the circular arc diamond grinding wheel is achieved, and the measurement results can be directly used for precise interpolation calculation of aspheric optical element ultra-precision grinding machining grinding wheel movement control point coordinates.