79results about How to "Numerically stable" patented technology

The invention discloses a method for precisely determining an orbit of a navigational satellite in real time based on a sliding data window. The main concept of the method is that when an estimation is carried out on a state Xk including an initial state of the satellite, a force model parameter, an earth rotation parameter, an atmospheric parameter, a station coordinate and the like; only first N measurements which are closest to k moment are utilized, while other measurements are completely abandoned, wherein N is a predetermined length of the sliding window; a precise satellite orbit initial value and the precise force model parameter of the Nth segmental arc can be acquired through establishing, combining, solving a normal equation and other steps; and a predicted orbit of the next moment can be acquired through an orbit integral and taken as a real-time orbit to be transmitted to a user. The method for determining the orbit of the satellite has the advantages of high speed of data processing, high orbit precision, stable numerical value and the like.

The invention discloses a vertical drainage plate consolidation saturated soft soil settlement process prediction method, which belongs to the research field of foundation treatment technology in geotechnical engineering. Considering the large deformation, the nonlinearity of material parameters, the boundary conditions, the time-varying vacuum load and surcharge, the unloading/reloading, the non-penetration of the shaft, the loss of vacuum along the well, the non-Darcy flow, the vertical and radial two-dimensional seepage flow and so on, the error is effectively reduced and the calculation precision is improved. The advantage of the method is more obvious for large strain problems. At the same time, the prediction method is simple and flexible, and the constitutive relation can be set flexibly according to the user's wishes, which solves the problems of incomplete considerations and inappropriate material parameters, which lead to large error in calculation results and difficult to beapplied in complex engineering environment. Therefore, the invention can be used for assisting the experimental research of a scientific research unit and predicting the consolidation of the engineering site.

The invention relates to the technical field of machine tool parts, in particular to a piezoelectric drive type electric spindle chip mingling detection device used for a numerical control machine tool. The piezoelectric drive type electric spindle chip mingling detection device comprises a conical clamp body used for clamping a tool handle and is characterized in that piezoelectric ceramic blockswhich can stretch out of the clamp body after being electrified are evenly distributed in the end, making contact with the tool handle, of the clamp body; the ends, being capable of stretching out ofthe clamp body, of the piezoelectric ceramic blocks are provided with electric conduction touch terminals; and the piezoelectric ceramic blocks include one movable piezoelectric ceramic block and multiple fixed piezoelectric ceramic blocks, and different electric properties are applied to the electric conduction touch terminals at the end portions of the fixed piezoelectric ceramic block and themovable piezoelectric ceramic blocks. During tool feeding of the numerical control machine tool, whether iron chips are mingled between the faces, making contact with the two end faces and two positions of a conical face of the tool handle clamp installed on the electric spindle of the numerical control machine tool, of the tool handle or not is detected, the detected alarming critical value can be preset, the numerical value is stable, and the detection accuracy, stability and reliability are improved.

The invention provides a method for detecting the water content and fat content in abalone through a low-field nuclear magnetic resonance technology. The method comprises the following first step of collecting samples, the second step of carrying out low-field nuclear magnetic analysis on the sample, the third step of measuring the samples, the fourth step of establishing a model, the fifth step of evaluating the model, and the sixth step of measuring the water content and the fat content of the samples to be detected. By means of the method, the water content and fat content in abalone can be measured at the same time, detection is rapid and accurate and free of the influence of the surface feature of abalone, and abalone is not damaged in the measuring process.

The invention relates to a precision discrete optical power flow calculation method of a VSC-HVDC (voltage source converter based high voltage direct current) containing AC/DC system. The calculation method is characterized by comprising the steps of firstly analyzing a power steady-state equation and other modified equations of the VSC-HVDC containing AC/DC system, then setting equality constraints and inequality constraints, and finally introducing a positive curvature quadratic penalty function into an interior point method. According to the calculation method, the interior point method is adopted to carry out optimization on continuous variables of the AC/DC system, the penalty function is introduced when a certain condition is reached, and discrete variables are constrained and optimized. Meanwhile, parameter values of the penalty function are continuously adjusted according to variations of the iteration quantity, and finally a purpose of optimizing the continuous variables and the discrete variables simultaneously is achieved.

The invention discloses an intelligent riding training system, and relates to the field of exercise and fitness. The intelligent riding training system comprises an exercise bicycle, a tablet intelligent terminal, a mobile phone intelligent terminal and an internet server. As a conventional training system of an exercise bicycle is optimized, the exercise data acquisition accuracy is improved, multiple actually tested data meaningful for exercise can be directly acquired, different fitting data standards can be unified and referable, data migration can be conveniently implemented, the individual training efficiency can be specifically improved, the activeness of training on schedule and exercise attention can be improved, the exercise injury risk can be reduced, relatively real riding experience can be provided, and thus the exercise effect of the exercise bicycle can be ultimately improved.

The invention discloses a low field nuclear magnetic resonance-applied frozen beef freshness nondestructive testing method. The low field nuclear magnetic resonance-applied frozen beef freshness nondestructive testing method comprises the following steps of (A) sample collection, (B) sample measurement, (C) sample low field nuclear magnetic analysis, (D) multiple freshness-related index measurement, (E) model establishment, (F) model assessment and (G) measurement of freshness of samples to be detected. By establishing a mathematical predication model reflecting fresh beef moisture content relaxation spectrum information and multiple indexes related to fresh beef freshness to accurately and reliably detect multiple indexes of an unknown fresh beef simultaneously such as thiobarbituric acidreactive substances (TBARS), volatile basic nitrogen (TVB-N) and pH, the low field nuclear magnetic resonance-applied frozen beef freshness nondestructive testing method can help predict the storagetime of the beef and achieve rapid and nondestructive detection and assessment of the freshness of the fresh beef. The low field nuclear magnetic resonance-applied frozen beef freshness nondestructivetesting method is rapid and accurate, avoids influence of beef surface properties, and during measurement, has no damage to the beef.

The invention relates to the field of electrochemical materials, in particular to a carbon coated layer thickness adjustable nanometer ferroferric oxide composite material, a preparation method and application thereof. The preparation method comprises the following steps: firstly, taking sugar, a catalyst and a ferric salt solution as raw materials, reacting for 0.1 to 24 h under the conditions that the pH is 5 to 10 and the temperature is 5 to 90 DEG C, preparing an iron-sugar complex, and thus preparing the carbon coated layer thickness adjustable nanometer ferroferric oxide composite material from the iron-sugar complex through in situ calcinations or a hydrothermal method. The nanometer ferroferric oxide composite material with a carbon coated layer is prepared through different in situ calcinations conditions or the hydrothermal method by using the iron-sugar complex as a precursor, and due to the fact that a multi-stage carbon structure array can play the role of a fixed frame for ferroferric oxide, the volume effect in the charge and discharge cycle process is reduced, and when the composite material serves as the negative electrode of a battery, the performance of the battery can be improved obviously. The thickness of the carbon coated layer inside the carbon coated ferroferric oxide composite material can be changed by changing the additive amounts of sugar and the catalyst.

The invention belongs to the technical field of radar signal processing, and particularly relates to a spectrum MUSIC method for achieving a uniform linear array by means of root computing of real polynomials. The spectrum MUSIC method includes the following steps of (1) computing coefficient vectors of the complex polynomials, (2) computing a window vector, (3) computing coefficients of the polynomials of all intervals, and (4) computing extreme values of MUSIC spectrums. According to the method, the coefficient vectors of the complex polynomials are computed quickly through Fourier transformation, the method of computing the extremities of the MUSIC spectrums is changed into the method of computing roots of multiple sets of low-order polynomials, and windowing Fourier transformation is carried out on related vectors of a signal subspace so that the coefficients of all the sets of the polynomials can be obtained. The defects that in the prior art, elaborate angle searching algorithms are needed, computation complexity is high and value stability is poor are overcome, and the method has the advantages that computation complexity is low and value stability is good and has great potential in estimation of the direction of arrival in low complexity.

A method and apparatus provide identification of a spherical error of a microscope imaging beam path in a context of microscopic imaging of a sample using a microscope having an objective. A coverslip that carries or covers the sample is arranged in the imaging beam path. A measurement beam is guided through the objective onto the sample in a decentered fashion that is outside an optical axis of the objective. The measurement beam is reflected at an interface of the coverslip with the sample and the reflected measurement beam is guided through the objective onto a detector. An intensity profile of the reflected measurement beam is detected with the detector and a presence of a spherical error from the intensity profile is determined qualitatively and/or quantitatively.

The invention discloses a gait double-side symmetric evaluation method based on a regression curve. The gait double-side symmetric evaluation method comprises the following steps of utilizing an acceleration sensor to obtain foot three-axis acceleration information in the gait movement, and denoising and pretreating the obtained acceleration information; extracting a denoised acceleration signal, respectively calculating double-side symmetric indexes in a continuous gait cycle, and quantitatively analyzing the symmetry of the gait. The gait double-side symmetric evaluation method has the characteristics that the simplicity and accuracy are realized; the broad application prospect is realized in the field of gait balance ability analysis and the like.

The invention relates to an analytical method and a device for a power ground network of an integrated circuit. The method comprises the following steps: firstly, establishing a matrix circuit equation of the power ground network; then constructing a projection matrix by a nonhomogeneous Amoldi method, and carrying out contragradient transformation on the matrix circuit equation of the power ground network to obtain a reduced order system; and finally, solving the transient response of the reduced order system to obtain the analytical result. The device applying the method comprises an input unit, an output unit, a program storage unit, an external bus, a memory, a storage management unit, an input/output bridging unit, a system bus and a processor. NHAR programs realizing the analytical method of the invention are stored in the program storage unit, and the circuit characteristic data of the power ground network are analyzed through the NHAR program. By analyzing the power ground network by the invention, numerical values can be ensured to be stable in the computational process, and very high computational accuracy can be achieved by very low complexity of computation, thereby solving the problem that the stableness of the numerical value and the computational efficiency can not be compromised in the computational process of the current methods.

The invention provides a parameter identification method based on graph theory and a device. an equation only comprising reactance parameters is established based on the graph theory; constrained conditions of observability of single power grid section parameters are determined; PMU measurement is adopted for parameter estimation for the devices which are equipped with PMU measurement; two-step parameter estimation is executed on the basis of residual error for the devices which are not equipped with PMU measurement. The pre-estimation of parameter values is quick and accurate; by means of the method, effective identification of high voltage loop grid parameters is achieved; suspicious device parameters can be accurately positioned so that the power grid technical data quality is improved and the practical level of electric power system network analysis is increased.

The invention belongs to the technical field of measurement, and in particular relates to a full-pressure tiny leak precision measurement system which is composed of a ball valve, a stop valve, a three-way sealing valve, a high-precision differential pressure gauge, an instrument control unit, a timer, a vacuum pump, a constant volume chamber, a gas distribution chamber, a gas cylinder and a pipejoint. The ball valve is adopted to cause the constant volume chamber with a known volume to be connected with the gas distribution chamber through a pipe, the stop valve is used to be connected withthe high-precision differential pressure gauge, and the three-way sealing valve is connected with the vacuum pump. After a part to be measured, the high-precision differential pressure gauge, the constant volume chamber and the gas distribution chamber reach the pressure balance, the ball valve is switched off, the stop valve is switched on to enable tiny leaked gas to be introduced into the constant volume chamber through a pipe, the gas flows to the gas distribution chamber through the high-precision differential pressure gauge, and the accumulated pressure change of the part to be measuredover time can be obtained. The full-pressure tiny leak precision measurement system has the advantages of being convenient to operate, small in size, wide in measurement range, high in measurement precision, not subjected to interference of gas source medium, capable of performing full pressure measurement, convenient to carry and low in cost.