31 results about "Relaxation curve" patented technology

The technology herein provides a dark blood delayed enhancement technique that improves the visualization of subendocardial infarcts that may otherwise be disguised by the bright blood pool. The timed combination of a slice-selective and a non-selective preparation improves the infarct/blood contrast by decoupling their relaxation curves thereby nulling both the blood and the non-infarcted myocardium. This causes the infarct to be imaged bright and the blood and non-infarct to both be imaged dark. The slice-selective preparation occurs early enough in the cardiac cycle so that fresh blood can enter the imaged slice.

The invention discloses a method for predicting the relaxation life of a spiral spring on the basis of the stress relaxation theory of a temperature accelerating material. The method comprises the following steps of: testing stress relaxation data of the spiral spring at test temperature and drawing a relaxation curve; drawing a semilogarithmic curve of load loss rate and time and fitting a regression equation; drawing a relation curve of relaxation factors A and B and temperature and fitting a regression equation; and calculating relaxation factors A (actual) and B (actual) of the spiral spring at an actual use temperature and calculating the relaxation life of the spiral spring. Compared with the traditional compression loading and unloading method, the method has the advantages that due to adoption of an RDL10 spring stress relaxation testing machine, errors are reduced and the accuracy is improved; and since a temperature accelerating mode is adopted for predicting the relaxation life of the spiral spring, the predication accuracy is higher, simultaneously the test period is greatly reduced, the efficiency is improved and the cost is lowered.

The invention relates to methods of measuring the overall elasticity of skin and determining the portion of the overall elasticity that is due to elastic properties and the portion of overall elasticity that is due to viscoelastic properties of the skin and correlating the results of the measurement to an individual's chronological age. The invention also relates to methods of measuring improvements in a person's skin health by measuring elasticity before, during and after human clinical trials of topical and/or oral treatment compositions. The parameters for determining elasticity are based on areas that are defined on a deformation/relaxation curve and require that an inflection point be determined for each skin sample analyzed.

The invention discloses a measurement method for the influence of residual stress on relaxation of tangential dual-bolt connection structures, and belongs to the field of mechanical engineering and mechanics. The measurement method includes the steps that the tangential dual-bolt connection structures of different residual-stress bolts are clamped through a tensile testing machine, and specific periods, specific frequencies and specific alternating loads of amplitude values are provided for the tangential dual-bolt connection structures; with cyclic loading, time-variable data of mechanics anddisplacement is obtained, variations of tangential-dual-bolt clamp force under different pieces of residual stress are analyzed and obtained, and a tensile test is repeatedly carried out multiple times; under comprehensive analysis of the mechanics data and the displacement data, the high-accuracy and accurate influence of relative displacement variations between joint surfaces under different pieces of residual stress on the clamp force of the tangential dual-bolt connection structures is finally obtained; attenuation of the residual stress for the clamp force of the tangential dual-bolt connection structures is quantitatively elucidated, and in the tightening and loading process, the interaction effect of the tangential dual-bolt connection structures under different pieces of horizontal residual stress is reflected through pre-tightening-force variations of two bolts and different relaxation curves.

In a magnetic resonance (MR) system and method for determining an MR system frequency for a region to be examined that has multiple materials therein, a first frequency spectrum is acquired by the execution of a first RF excitation sequence. A second frequency spectrum for the region is acquired by radiation of an RF inversion pulse and execution of a second RF excitation sequence, at the point in time at which the relaxation curve of one of the materials has a zero-crossing. Subsequently, echo signals excited by the second RF excitation sequence are read out, from which a frequency spectrum is determined. The first frequency spectrum and the second frequency spectrum are compared. On the basis of the comparison, maxima of the first frequency spectrum are allocated to different materials. The system frequency is determined on the basis of the allocation of the maxima.

The invention discloses a safety evaluation method for a tunnel anchorage. Long-term shear strength parameters of surrounding rock of the tunnel anchorage are used as a safety evaluation basis for thetunnel anchorage; the long-term shear strength parameters are measured according to the following steps: simulating engineering site surrounding rock, and preparing a tunnel anchor surrounding rock model test piece; establishing a shear strength relaxation curve of the test piece under different vertical loads through a constant-load consolidation drainage shear test; converting the shear strength relaxation curve into an lgt1/[tau] curve, and establishing a long-term strength equation of the shear strength of the test piece along with time change under different vertical loads; and selectinga required long-term strength equation under a vertical load, and determining a long-term shear strength parameter of the test piece, namely the long-term shear strength parameter of the tunnel anchor surrounding rock. According to the invention, the long-term shear strength parameter is adopted, so that the mechanical property of the rock mass under continuous shear load can be more reliably reflected, and the deviation between a test result and engineering practice is greatly reduced.

The invention relates to a method for measuring a prestressed anchor rod anchorage force relaxation loss rate, and belongs to the field of technologies related with geotechnical engineering. The main steps include A. installing a resistor disc and a wire on a prestressed anchor rod; B determining anchor rod anchoring prestress Pi and resistance Ri variation law curves; C. determining an anchor rod anchorage force reduction value [delta]Pi and resistance variation value [delta]Ri variation relation curve; D. determining [delta]Pt and [delta]Pt-t relaxation curves according to the curve obtained in the Step C; E. determining corresponding anchorage force relaxation rate [lambda]t and an average relaxation rate parameter at any time t; and F. determining a prestressed anchor rod anchorage force loss rate [eta]t. The method provided by the invention basically can measure the corresponding anchorage force relaxation rate at any time t after anchoring of the anchor rod, thereby providing an accurate basis for engineering progress, and reducing risks of disaster occurrence.

A sheet feeder is provided that includes a feeding unit configured to feed a sheet through a feeding path and a guide portion that is bent in a shape of a relaxation curve and configured to feed the sheet thereon and turn a feeding direction of the sheet.

The embodiment of the invention provides a method and device for drawing a road in an electronic map, drawing equipment and a storage medium, and the method comprises the steps: carrying out the linear fitting of collected road shape point data, and obtaining a curve coefficient and a starting point coordinate of a curve corresponding to the road; substituting the obtained curve coefficient and the starting point coordinate of the curve corresponding to the road into an equation of a relaxation curve of the road, and rendering to obtain the relaxation curve of the road; wherein the relaxationcurve of the road is obtained by deformation of a unit convolution curve, an equation of the relaxation curve of the road is expressed as a correlation between the unit convolution curve and a corresponding deformation coefficient, and a preset relation exists between the deformation coefficient and a curve coefficient of a curve corresponding to the road. By adopting the scheme, the precision stability of the road relaxation curve and the smoothness of the line shape in the electronic map can be improved.

A system for non-invasive analysis of tissue includes a non-ferromagnetic handheld probe (15) distinguishing between nerves, muscles and blood vessels. A magnetic field source in the probe generates a uniform, time-invariant magnetic field within a volume of tissue and contains an inductive coil (19) that receives RF excitation signals in a specific frequency range related to the field strength thereby generating excitation signals perpendicular to a direction of the magnetic field and magnetizing a slice of the living tissue having depth and thickness predetermined by the field strength whereby only living tissue in each slice responds to nuclear spin echo signals. A control unit generates time patterns of the excitation signals and extracts data indicative of the nuclear spin echo signals from the living tissue, determines relaxation curves having time constants T1, T2 and performs statistical processing of the relaxation curves to determine the type of tissue excited by the probe.

The invention provides an incomplete relaxation curve mileage back calculation method. The method comprises the following steps: judging intersection points JDs of an intersection point interval wherea point P is located and curve sections corresponding to the JDs according to line coordinates and line design information of the point P; finding a point P0 closest to the point P on the curve segment corresponding to the JDs; judging whether the linear section where the point P0 is located on the curve section is an incomplete relaxation curve or not; and if the linear section where the point P0 is located on the curve section is an incomplete relaxation curve, complementing the incomplete relaxation curve into a complete relaxation curve, and calculating the line mileage and offset distance d of the point P0. According to the method, the linear segment of the point P0 on the curve segment can be judged only according to the tangent vector of each main point on the curve segment corresponding to the intersection point and the relationship between each main point and the vector of the point P, whether the linear segment is an incomplete relaxation curve or not can be further judged,all line elements do not need to be calculated, and the linear judgment process is simplified.

The invention provides a quantitative characterization method of cell membrane tension, which combines a cell membrane tension model and a cytoplasm viscoelasticity model, and performs quantitative characterization on the cell membrane tension by using an atomic force microscope. The method specifically comprises the following steps: (1) obtaining single cell force relaxation signal data based on an AFM nanoindentation experiment; (2) constructing a cell power relaxation curve equation; and (3) quantitative calculation of cell membrane tension. The detection means for quantitatively detecting the membrane tension of the living cells, provided by the invention, is helpful for people to have further deeper understanding on cell behaviors, and also provides a new view angle and direction for people to carry out early diagnosis, regulation and treatment on various diseases by regulating the physical characteristics of the cells.

The invention discloses a fastener stress state evaluation method and device, and relates to the technical field of fastener maintenance and detection. The evaluation method comprises the following steps: carrying out a relaxation fatigue interaction test on a fastener material at a preset temperature; collecting stress values of the fastener material corresponding to different fastening times under the conditions of different strain amplitudes and different retention time; obtaining a stress relaxation curve cluster according to the stress value collected by the data collector; fitting the stress relaxation curve cluster to obtain a first stress relaxation fitting curve; obtaining a residual stress value at the preset temperature according to the first stress relaxation fitting curve; andcomparing the residual stress value with a preset residual stress threshold value, and evaluating the stress state of the fastener under the condition of the residual stress value. The technical problem that in the prior art, only a pure high-temperature relaxation curve is used for evaluating the residual stress of repeated fastening inaccurately is solved.

Flow measurement of hydrogen density, volumetric concentrations, and longitudinal relaxation times and transverse relaxation times have all n components in pairs different to each other. The method has the steps of: enclosing a mixture inside a probe volume and polarizing the mixture with a magnetic field; measuring the mixture enclosed inside the probe volume in terms of its longitudinal or transverse relaxation behaviour by means of pulsed electromagnetic waves at least n times with a different volumetric share of its components to measure at least n different relaxation curves; obtaining the relaxation times from the relaxation curves; obtaining the thermal equilibrium magnetizations M₀ of the individual components from the relaxation curves; and correlating yielded thermal equilibrium magnetizations M₀ of the individual components to calculate the hydrogen densities and the volumetric share of the components for each relaxation curve.

The invention relates to the field of shield tunnel rubber sealing gaskets, in particular to a method for determining the long-term character of a shield tunnel rubber sealing gasket. The method comprises the steps of according to the relationship that the modulus is reduced along with the increase of time and the curve shape only moves horizontally at different temperatures, horizontally moving a short-term stress relaxation curve and a short-term creep curve to obtain a corresponding relaxation modulus sub-curve and a corresponding creep compliance sub-curve; horizontally translating the relaxation modulus sub-curve to obtain a relaxation modulus main curve according to a relationship between a stress relaxation behavior under one temperature or stress or a creep behavior under strain and a stress relaxation behavior under another temperature or stress or a creep behavior under strain; horizontally translating the creep compliance sub-curve to obtain a creep compliance main curve; and predicting the relaxation modulus value of an EPDM test sample in specified time from the relaxation modulus main curve, and predicting the creep compliance of the EPDM test sample in specified time from the creep compliance main curve.

The invention provides a calculation method for protecting a cloud island type station end horn mouth and related parameters thereof. The shortest station end horn mouth length is obtained under the conditions that the comfort degree of passengers is guaranteed, the speed of a train is not limited or the influence is slight (the influence degree is less than 5%), and the length of a circular curveand a clamping straight line is not smaller than the length of one train (not smaller than the full axle distance under difficult conditions). The specific parameters of the horn mouth are set as follows: the radius R is equal to 400m, the relaxation curve length l is equal to 10m, the actual superelevation rate h is equal to 2 percent, the rotation angle theta is equal to 2 degrees, 52 minutes and 00 seconds, and the allowable passing speed V is equal to 45km/h; and the second curve parameters of the horn mouth are set as follows: the radius R is 500 m, the relaxation curve length l is 16 m,the actual superelevation rate h is 2.5%, the rotation angle theta is 2 degrees 52 minutes 00 seconds, and the allowable passing speed V is 60 km/h. Compared with the prior art, the method has the beneficial effects that the purposes of reducing the engineering investment and improving the landscape effect are achieved.

A method determines a calibration specification specifying a functional correlation between an NMR measurement variable, determined using an NMR measuring device, for a material to be analyzed and a humidity contained in the material to be analyzed. The method includes provision of a relaxation curve of the material having a known humidity; determination of a relaxation time distribution from the relaxation curve provided; and determination of an approximate relaxation time distribution relative to at least one other humidity. The at least one other humidity is less than the known humidity. The method further includes reconstruction of another relaxation curve from the approximate relaxation time distribution; determination of an expected NMR measurement variable from the reconstructed other relaxation curve for the at least one other humidity; and determination of the calibration specification as a function of the humidity contained in the material, in accordance with the determinable NMR measurement variable.