30 results about "Velocity dispersion" patented technology

Normal group velocity dispersion mode-locked optical frequency combs are provided on-chip. On-chip coherent frequency comb generation includes pulses showing temporal durations of about 74 fs. Pump detuning and bandpass filtering are provided for stabilizing and shaping the pulses from normal group velocity dispersion microresonators.

The invention provides a detection apparatus of carrier envelope phase signals. The detection apparatus is characterized by comprising a pulse oscillator, a fiber amplifier, a spectrum spread device and a collinear type self-reference f-2f carrier envelope phase detection module which are successively connected through an optical path, wherein the collinear type self-reference f-2f carrier envelope phase detection module comprises multiple lenses, a PPLN crystal, a YV04 crystal and a photoelectric detector which are connected through an optical path, the lens is used for converting fiber light output by the spectrum spread device into space light, the YV04 crystal is used for introducing time-delay amounts of fundamental frequency light and frequency multiplication light, and the YV04 crystal is internally of an oblique cleft structure whose left portion and right portion can be vertically adjusted. Femtosecond pulses are injected into high-nonlinearity fibers for generating needed long-wave signals and short-wave signals, phase delays of long-wave signal pulses and short-wave signal pulses are optimized through polarization dispersion and envelope velocity dispersion of the YV04 crystal, and compared to a method of modifying a time-delay amount by use of space light path adjustment in a conventional apparatus, the accuracy is greatly improved.

The invention discloses a method for two frequency point sound measurement of heat capacity of ideal gas. First two-frequency signals with sound frequencies being Omega1 and Omega2 respectively occur; the two-frequency signals are converted into mechanical sound waves respectively, transmission sound velocities c(Omega1) and c(Omega1) of the mechanical sound waves in an ideal gas medium and relaxation absorption coefficient Alpha(Omega1) and Alpha(Omega2) are respectively measured; according to the measured c(Omega1), c(Omega1), Alpha(Omega1) and Alpha(Omega2), effective heat capacities as shown in the descriptions are obtained by the formula as shown in the description, vibrational coupling molar heat capacities, as shown in the description, of the ideal gas are obtained by calculating the effective heat capacities as shown in the descriptions; and finally the heat capacity Cv of the ideal gas is obtained through a formula as shown in the description according to the vibrational coupling molar heat capacities. According to the measurement method, the influence of acoustic disturbance on gas heat capacity measurement results is effectively eliminated, and system errors generated in a conventional gas heat capacity acoustic measurement method due to sound velocity dispersion can be avoided.

Method for estimating fluid heterogeneity in a subsurface region from seismic wave attenuation or velocity dispersion that is either measured or extracted from geophysical data (210). A rock physics model in the form of a mathematical relationship is selected that relates attenuation or velocity to frequency and to physical properties that are related to fluid heterogeneity (220). The model, or asymptotes (230) representing the model's behavior at frequency extremes, is inverted (240) and that relationship is used to obtain (250) one or more of the physical properties related to fluid heterogeneity, such as characteristic length scale for fluid saturation heterogeneities (270) and relative volume fractions of the fluids saturating the pore space (280).

The invention relates to a pulse compression technology based broadband measurement method for sound velocity and attenuation in a sediment. During sound velocity measurement, firstly the receipt signal when the sound wave only penetrates a glass jar without the presence of a sand sample is recorded, then a sound source and a hydrophone are moved to a thick sand sample side to record a corresponding receipt signal. During attenuation coefficient measurement, the receipt signals penetrating two sand samples of different thicknesses are recorded successively. In the measurement, the receipt signal under each state is collected for at least 30 times, statistic analysis on the measurement results of sound velocity and attenuation coefficient are carried out, and the confidence interval determined by the result of a mean value+ / -standard deviation is taken as the final measurement result. The method provided by the invention can acquire the variation relationship of the sound velocity dispersion and attenuation along with the frequency in the sediment within the measurement band at a time, and provides a new idea for realizing rapid acquisition of the sound velocity and attenuation.

The embodiment of the application provides a method and apparatus for calculating seismic wave characteristic information of a random porous media model. The method comprises: pretreatment is carried out on a rack sample and statistic characteristic information of an elastic parameter of the rock sample is obtained according to rock sample analysis data after the pretreatment; a random filed is established based on the statistic characteristic information; calculation is carried out to obtain a random porous media effective longitudinal wave modulus of saturated fluid; and according to the random porous media effective longitudinal wave modulus of saturated fluid, calculation is carried out to obtain seismic wave characteristic information. According to the technical scheme, the seismic wave characteristic information, including velocity dispersion and attenuation of the seismic wave, of the random porous media model can be calculated accurately and the velocity dispersion and attenuation information can reflect the influence on the seismic wave by the porous fluid effectively, so that the support can be provided for improving precision of the seismic quantitative interpretation.

A novel surface acoustic wave device with a decreased velocity dispersion and a low insertion loss as well as the fabrication method therefor is provided. The surface acoustic wave device includes a substrate, an insulating layer with an indentation on the substrate, a silicon layer with a first portion on the insulating layer and a second portion suspended above the indentation, a piezoelectric layer on the first and the second portions of the silicon layer, and at least an electrode on the piezoelectric layer.

The invention discloses methods and devices for determining reflection coefficient dispersion and reflection energy and identifying a gas layer. The method for determining reflection coefficient dispersion comprises the steps: preserving amplitude of seismic data and extracting angle gather; selecting the angle gather with a proper angle according to the quality of the seismic data; determining velocity of longitudinal waves, velocity of transverse waves and density by using a prestack inversion method; determining longitudinal wave quality factors and transverse wave quality factors of a stratum; and determining the reflection coefficient dispersion. The method for determining reflection energy comprises the step of determining the coefficient of reflection energy. The method for identifying the gas layer comprises the steps: determining the reflection energy; determining a threshold value according to the situations of well drilling and well testing; and identifying the stratum, whose reflection energy is lower than the threshold value, as the gas layer. By adopting the methods, the velocity dispersion and energy change of the stratum containing gas can be accurately reflected by the reflection coefficients, the reflection energy can be accurately reflected, accordingly, the gas-bearing property of a subsurface reservoir can be judged, and the interpretation ambiguity for the identification of the gas layer is effectively reduced.

Normal group velocity dispersion mode-locked optical frequency combs are provided on-chip. On-chip coherent frequency comb generation includes pulses showing temporal durations of about 74 fs. Pump detuning and bandpass filtering are provided for stabilizing and shaping the pulses from normal group velocity dispersion microresonators.

The invention provides a detection apparatus of carrier envelope phase signals. The detection apparatus is characterized by comprising a pulse oscillator, a fiber amplifier, a spectrum spread device and a collinear type self-reference f-2f carrier envelope phase detection module which are successively connected through an optical path, wherein the collinear type self-reference f-2f carrier envelope phase detection module comprises multiple lenses, a PPLN crystal, a YV04 crystal and a photoelectric detector which are connected through an optical path, the lens is used for converting fiber light output by the spectrum spread device into space light, the YV04 crystal is used for introducing time-delay amounts of fundamental frequency light and frequency multiplication light, and the YV04 crystal is internally of an oblique cleft structure whose left portion and right portion can be vertically adjusted. Femtosecond pulses are injected into high-nonlinearity fibers for generating needed long-wave signals and short-wave signals, phase delays of long-wave signal pulses and short-wave signal pulses are optimized through polarization dispersion and envelope velocity dispersion of the YV04 crystal, and compared to a method of modifying a time-delay amount by use of space light path adjustment in a conventional apparatus, the accuracy is greatly improved.

The embodiment of the application provides a method and apparatus for calculating seismic wave characteristic information of a random porous media model. The method comprises: pretreatment is carried out on a rack sample and statistic characteristic information of an elastic parameter of the rock sample is obtained according to rock sample analysis data after the pretreatment; a random filed is established based on the statistic characteristic information; calculation is carried out to obtain a random porous media effective longitudinal wave modulus of saturated fluid; and according to the random porous media effective longitudinal wave modulus of saturated fluid, calculation is carried out to obtain seismic wave characteristic information. According to the technical scheme, the seismic wave characteristic information, including velocity dispersion and attenuation of the seismic wave, of the random porous media model can be calculated accurately and the velocity dispersion and attenuation information can reflect the influence on the seismic wave by the porous fluid effectively, so that the support can be provided for improving precision of the seismic quantitative interpretation.

Described here are systems and methods for ultrasound processes using shear wave attenuation and velocity derived from k-space analysis by analyzing spatial frequency domain data.

The invention discloses a constant-force shell delivery device for split-charged shells. The constant-force shell delivery device comprises a force applying mechanism, an elastic force mechanism and a force release mechanism, wherein the force applying mechanism is used for externally applying thrust force, the elastic force mechanism is used for generating compression elastic force under the action of the external thrust force, and the force release mechanism is used for releasing the constant elastic force of compression so as to push a shell to move. The free end of the force applying mechanism is a force applying end used for externally applying thrust force, the non-free end of the force applying mechanism is connected with the non-free end of the force release mechanism through the elastic force mechanism, and the free end of the force release mechanism is pressed against the rear end face of a shell. The constant-force shell delivery device is simple in structure and free of magnitude of thrust force of an ammunition carrier; every time a shell is charged, the shell can be pushed in place at constant shell delivery force, and initial velocity dispersion caused by inconsistent shell delivery force can be eliminated; the magnitude of the shell delivery force can be adjusted in a stepless mode according to different requirements for physique of ammunition carriers, and thus the constant-force shell delivery device can be widely applied. The constant-force shell delivery device is suitable for charging split-charged shells.

The embodiment of the application provides an AVAF simulation method and apparatus based on a multi-scale rock physical model. The method comprises: determining a periodic layered plaque saturated medium model of a reservoir stratum and determining an improved rock matrix modulus of a microscopic jet flow model of the reservoir stratum; substituting the improved rock matrix modulus into the periodic layered plaque saturated medium model to obtain a multi-scale rock physical model of the reservoir stratum; determining a reservoir medium parameter value of the reservoir stratum and a seismic wave dispersion parameter value of the multi-scale rock physical model and establishing a layered media model containing a velocity dispersion interlayer; and carrying out frequency-domain seismic forward modeling on the layered media model with the velocity dispersion interlayer to obtain a frequency-dependent seismic response characteristic of the layered medium model with the velocity dispersion interlayer. Therefore, accurate rock elastic characteristics and seismic response characteristics of tight sandstones can be obtained.

The present invention relates to a method and device for determining the layer velocity at the seismic scale. The method includes: obtaining the layer velocity under the logging frequency band; determining the rock physical statistical relationship according to the layer velocity under the logging frequency band and the corresponding known quality factor Correlation coefficient; establish the first objective function according to the layer velocity in the logging frequency band and the correlation coefficient in the petrophysical statistical relationship, and obtain the layer velocity at the seismic scale satisfying the velocity-dispersion relationship according to the first objective function; determine the current position The length of the scale coarsening window, using the length of the scale coarsening window at the current position to obtain the number of sample points in the scale coarsening window at the current position; and determining the current position according to the layer velocity at the seismic scale satisfying the velocity-dispersion relationship and the corresponding number of sample points The layer velocity after the coarsening of the seismic scale at the current position is corrected to obtain the layer velocity at the seismic scale that accurately reflects the travel time information of seismic wave propagation.

The invention provides a seismic wave attenuation and velocity dispersion prediction method in a complex heterogeneous reservoir medium, which belongs to the field of hydrocarbon fossil energy exploration and development. The method includes: (1) carrying out a two-dimensional petrophysical modeling for the reservoir rock unit according to the lithology, fluid-bearing properties, and fluid saturation Sg of the heterogeneous reservoir medium; (2) obtaining the physical model in step (1). In modeling, a conventional two-dimensional seismic wave propagation simulation numerical experiment is implemented, and the propagation of elastic waves in the reservoir medium is realized by applying a point source, the stress field and velocity field of each time layer are obtained, and the strain field at any point in space is obtained. ; (3) When the conventional two-dimensional seismic wave propagation simulation numerical experiment is completed, record the time records of the stress field and strain field; (4) Calculate the average stress and strain fields of the REV element based on the macroscopic averaging principle, where ψ∈{τxx, τzz , εxx, εzz}.

The embodiment of the invention discloses a method and device for computing porous medium acoustic velocity containing non-Newtonian fluid. The method comprises steps of: establishing a porous medium micro-tube flow model, deriving dissipation energy inside the non-Newtonian fluid, shear stress between fractional order derivative Maxwell fluid and solid, and the average flow velocity of the non-Newtonian fluid according to the flow model, and computing a fluid-solid relative motion energy dissipation factor according to the shear stress and the average flow velocity; establishing a porous medium wave equation containing a non-Newtonian fluid effect on the basis of the fluid-solid relative motion energy dissipation factor; performing plane-wave analysis on the established porous medium wave equation to obtain a dispersion relation containing the non-Newtonian fluid effect and computing longitudinal wave velocity dispersion and attenuation. The method and device for computing porous medium acoustic velocity containing non-Newtonian fluid may relatively accurately predict the dispersion and the attenuation of the acoustic velocity in an unconventional oil and gas reservoir.

Method for inverting seismic data to obtain reflection properties by estimating or measuring (301) the source signature for the seismic data, then inverting (302) simultaneously for subsurface formation properties or reflection properties and for the amplitude attenuation and velocity dispersion effects integrated over the raypath from the source to the reflectors and to the receiver.