scholarly journals Determination of the parameters of a four-point partially coherent model of radar object based on its equivalence to a five-point non-coherent model

2019 ◽  
Vol 29 (4) ◽  
pp. 35-43
Author(s):  
A. O. Podkopayev ◽  
M. A. Stepanov ◽  
S. V. Tyrykin
Keyword(s):  
Geometric Model ◽  
Software Modeling ◽  
Point Model ◽  
Partially Coherent ◽  
Object Based ◽  
The Matrix ◽  
Analytical Relations ◽  
Correlated Signals ◽  
Theoretical Results

The problem of determining the parameters of a four-point partially coherent model of radar object based on its equivalence to a five-point non-coherent model was solved. The obtained analytical relations describe the spectral and correlation characteristics of signals delivered to the emitters of the four-point partially coherent model of the matrix simulator emitting statistically dependent normal random processes. Correlations are defined based on the equivalence of a four-point model emitting correlated signals and five-point model emitting uncorrelated signals. Moreover, the projections of an original five-point non-coherent model onto two mutually orthogonal coordinate axes are reviewed. Based on that, the projections onto the same axes of a four-point partially coherent model are derived. Expressions relating to the derived projections and required four-point partially coherent model are obtained. Conditions that are necessary for the synthesis of an adequate five-point non-coherent distributed radar target geometric model are described. Based on them, the limitations within which a transition from non-coherent five-point models to partially coherent four-point models is possible are formulated. The obtained theoretical results are confirmed by software modeling.

SYNTHESIS OF TWO-POINT PARTIALLY COHERENT MODEL, PROVIDING SPECIFIED CORRELATION CHARACTERISTICS OF ANGULAR NOISE, BASED ON ITS EQUIVALENCE OF THREE-POINT NON-COHERENT MODEL WITH SEPARABILITY OF SPATIAL AND TEMPORAL COORDINATES

2019 ◽  
pp. 16-21
Author(s):  
A. O. Podkopayev ◽  
M. A. Stepanov
Keyword(s):  
Geometric Model ◽  
Point Model ◽  
Spectral Correlation ◽  
Partially Coherent ◽  
Temporal Variables ◽  
Digital Modeling ◽  
Dimensional Object ◽  
Probability Density Distributions ◽  
Correlation Properties ◽  
Correlated Signals

The paper considers approaches developed for the synthesis of a two-point geometric model that emits correlated signals and forms angular noise with given spectral-correlation properties, based on its equivalence of a three-point model that emits noncorrelated signals. Analytical relationships have been obtained that allow us to determine the spectral correlation characteristics of the signals supplied to the emitters of the two-point partially coherent model. The basis for the synthesis of a two-point model, emitting correlated signals, is a three-point model, emitting non-correlated signals. The considered models can replace a one-dimensional object that has the property of separating the spatial and temporal variables in functions that determine the distribution of the density of the auto- and cross-correlation quadrature components of the echo signal over the object. In this case, all points of the object being replaced reflect echoes with the same spectral and correlation properties. The obtained theoretical results are confirmed by digital modeling. The obtained probability density distributions of the angular noise and their correlation functions coincide for the two considered models.

EVALUATION AND COMPENSATION OF SYSTEMATIC ERRORS OF CALIBRATION OF MATRIX SIMULATOR

2018 ◽  
pp. 24-28
Author(s):  
A. V. Kiselev ◽  
A. O. Podkopaev ◽  
M. A. Stepanov
Keyword(s):  
Phase Error ◽  
Precise Determination ◽  
Random Component ◽  
Compensation Error ◽  
The Matrix ◽  
Calibration Algorithm ◽  
Phase Calibration ◽  
Analytical Relations ◽  
Theoretical Results

The problem of phase calibration of the matrix simulator is considered. The phase error at the point of reception is divided into systematic and random. Analytic relationships are obtained that allow one to evaluate and compensate for the systematic error in the calibration of the phases of the signals emitted by the matrix simulator, caused by the geometric separation of the phase centers of the antenna and the antenna of the calibration receiver. The random component of the phase error is compensated by the calibration algorithm. Analytical relations are obtained for determining the compensation error due to the non-precise determination of the coordinates of the emitting part of the matrix simulator and the phase center of the antenna of the measuring receiver. The magnitude of this error is determined for the typical location of the antennas of the device under investigation, the measuring receiver and the matrix simulator when performing semi-realistic simulation. The description of the laboratory stand of the developer of the matrix imitator is given. The obtained theoretical results are confirmed experimentally at the booth of the matrix imitator developer.

scholarly journals The two-dimensional distributed object four-point model based on correlated signals emitters

2018 ◽  
Vol 28 (4) ◽  
pp. 28-34 ◽  
Author(s):  
A. O. Podkopaev ◽  
M. A. Stepanov ◽  
S. V. Tyrykin
Keyword(s):  
Distribution Density ◽  
Geometric Model ◽  
Probability Density Distribution ◽  
Two Dimensional ◽  
Phase Front ◽  
Point Model ◽  
Spectral Correlation ◽  
Distributed Object ◽  
Angular Coordinates ◽  
Correlated Signals

The paper considers methods for modeling fluctuations of the phase front of an electromagnetic wave reflected from a radar object (reflections) using models that emit statistically related signals. Previously, such models were considered only in relation to objects distributed over a single angular coordinate. A two-dimensional geometric model, emitting statistically related signals, was proposed for replacement of reflections from radar objects distributed over two angular coordinates. The emitters of the model are located at the vertices of the square. Expressions are obtained for determining the characteristics of signals supplied to the emitters of such model, at which the model provides the required parameters of the probability distribution density of the angular noise of the distributed object. Within the framework of the model under study, it is proved that it is possible to control the parameters of the probability density distribution of angular noise along two coordinate axes independently. The equivalence of the four-point partially coherent model and the five-point incoherent in terms of providing the probability characteristics of the angular noise is shown, and the limits of this equivalence are also determined. The proven equivalence of models allows developing an apparatus for the synthesis of spectral-correlation characteristics.

Lateral resolution of the electron microbeam analysis

1978 ◽  
Vol 36 (1) ◽  
pp. 542-543
Author(s):  
H.J. Dudek
Keyword(s):  
Quantitative Analysis ◽  
Depth Resolution ◽  
Lateral Resolution ◽  
Cylindrical Particle ◽  
Correction Procedure ◽  
X Ray ◽  
Element Concentrations ◽  
Microbeam Analysis ◽  
The Matrix

The chemical inhomogenities in modern materials such as fibers, phases and inclusions, often have diameters in the region of one micrometer. Using electron microbeam analysis for the determination of the element concentrations one has to know the smallest possible diameter of such regions for a given accuracy of the quantitative analysis.In th is paper the correction procedure for the quantitative electron microbeam analysis is extended to a spacial problem to determine the smallest possible measurements of a cylindrical particle P of high D (depth resolution) and diameter L (lateral resolution) embeded in a matrix M and which has to be analysed quantitative with the accuracy q. The mathematical accounts lead to the following form of the characteristic x-ray intens ity of the element i of a particle P embeded in the matrix M in relation to the intensity of a standard S

Determination of the phase structure of polymerblends by electron microscopy

1978 ◽  
Vol 36 (1) ◽  
pp. 492-493
Author(s):  
Dr. G. Kaemof
Keyword(s):  
Screw Extruder ◽  
Electron Microscopic ◽  
Thin Sections ◽  
Single Screw Extruder ◽  
Transmission Electron ◽  
The Matrix ◽  
Twin Screw ◽  
Special Case ◽  
Microscopic Investigations

A mixture of polycarbonate (PC) and styrene-acrylonitrile-copolymer (SAN) represents a very good example for the efficiency of electron microscopic investigations concerning the determination of optimum production procedures for high grade product properties.The following parameters have been varied:components of charge (PC : SAN 50 : 50, 60 : 40, 70 : 30), kind of compounding machine (single screw extruder, twin screw extruder, discontinuous kneader), mass-temperature (lowest and highest possible temperature).The transmission electron microscopic investigations (TEM) were carried out on ultra thin sections, the PC-phase of which was selectively etched by triethylamine.The phase transition (matrix to disperse phase) does not occur - as might be expected - at a PC to SAN ratio of 50 : 50, but at a ratio of 65 : 35. Our results show that the matrix is preferably formed by the components with the lower melting viscosity (in this special case SAN), even at concentrations of less than 50 %.

Polishing process effect on the image of dispersed precipitates

1984 ◽  
Vol 42 ◽  
pp. 534-535
Author(s):  
C.T. Hu ◽  
C.W. Allen
Keyword(s):  
Matrix Material ◽  
Specimen Preparation ◽  
Second Phase ◽  
Precipitate Particle ◽  
Polishing Process ◽  
Second Phase Particles ◽  
The Matrix ◽  
Surface Profiles ◽  
Thinning Process

One important problem in determination of precipitate particle size is the effect of preferential thinning during TEM specimen preparation. Figure 1a schematically represents the original polydispersed Ni3Al precipitates in the Ni rich matrix. The three possible type surface profiles of TEM specimens, which result after electrolytic thinning process are illustrated in Figure 1b. c. & d. These various surface profiles could be produced by using different polishing electrolytes and conditions (i.e. temperature and electric current). The matrix-preferential-etching process causes the matrix material to be attacked much more rapidly than the second phase particles. Figure 1b indicated the result. The nonpreferential and precipitate-preferential-etching results are shown in Figures 1c and 1d respectively.

scholarly journals Simplified and Rapid Determination of Primaquine and 5,6-Orthoquinone Primaquine by UHPLC-MS/MS: Its Application to a Pharmacokinetic Study

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4357
Author(s):  
Waritda Pookmanee ◽  
Siriwan Thongthip ◽  
Jeeranut Tankanitlert ◽  
Mathirut Mungthin ◽  
Chonlaphat Sukasem ◽  
...  
Keyword(s):  
Pharmacokinetic Study ◽  
High Performance ◽  
Rapid Determination ◽  
Active Metabolites ◽  
Chromatography Tandem Mass Spectrometry ◽  
Accuracy And Precision ◽  
The Matrix ◽  
Liquid Chromatography Tandem Mass ◽  
Isocratic Mode

The method for the determination of primaquine (PQ) and 5,6-orthoquinone primaquine (5,6-PQ), the representative marker for PQ active metabolites, via CYP2D6 in human plasma and urine has been validated. All samples were extracted using acetonitrile for protein precipitation and analyzed using the ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC-MS/MS) system. Chromatography separation was carried out using a Hypersil GOLDTM aQ C18 column (100 × 2.1 mm, particle size 1.9 μm) with a C18 guard column (4 × 3 mm) flowed with an isocratic mode of methanol, water, and acetonitrile in an optimal ratio at 0.4 mL/min. The retention times of 5,6-PQ and PQ in plasma and urine were 0.8 and 1.6 min, respectively. The method was validated according to the guideline. The linearity of the analytes was in the range of 25–1500 ng/mL. The matrix effect of PQ and 5,6-PQ ranged from 100% to 116% and from 87% to 104% for plasma, and from 87% to 89% and from 86% to 87% for urine, respectively. The recovery of PQ and 5,6-PQ ranged from 78% to 95% and form 80% to 98% for plasma, and from 102% to from 112% to 97% to 109% for urine, respectively. The accuracy and precision of PQ and 5,6-PQ in plasma and urine were within the acceptance criteria. The samples should be kept in the freezer (−80 °C) and analyzed within 7 days due to the metabolite stability. This validated UHPLC-MS/MS method was beneficial for a pharmacokinetic study in subjects receiving PQ.

scholarly journals Simultaneous Determination of Nitroimidazoles and Quinolones in Honey by Modified QuEChERS and LC-MS/MS Analysis

2018 ◽  
Vol 2018 ◽  
pp. 1-12 ◽  
Author(s):  
Haiyan Lei ◽  
Jianbo Guo ◽  
Zhuo Lv ◽  
Xiaohong Zhu ◽  
Xiaofeng Xue ◽  
...  
Keyword(s):  
Recovery Rates ◽  
Inhibition Effect ◽  
Standard Curve ◽  
Modified Quechers ◽  
Relative Standard ◽  
Acacia Honey ◽  
The Matrix ◽  
Liquid Chromatography Tandem Mass ◽  
Standard Deviations

This study reports an analytical method for the determination of nitroimidazole and quinolones in honey using liquid chromatography-tandem mass spectrometry (LC-MS/MS). A modified QuEChERS methodology was used to extract the analytes and determine veterinary drugs in honey by LC-MS/MS. The linear regression was excellent at the concentration levels of 1–100 ng/mL in the solution standard curve and the matrix standard curve. The recovery rates of nitroimidazole and quinolones were 4.4% to 59.1% and 9.8% to 46.2% with relative standard deviations (RSDs) below 5.2% and the recovery rates of nitroimidazole and quinolones by the matrix standard curve ranged from 82.0% to 117.8% and 79% to 115.9% with relative standard deviations (RSDs) lower than 6.3% in acacia and jujube honey. The acacia and jujube honeys have stronger matrix inhibition effect to nitroimidazole and quinolones residue; the matrix inhibition effect of jujube honey is stronger than acacia honey. The matrix standard curve can calibrate matrix effect effectively. In this study, the detection method of antibiotics in honey can be applied to the actual sample. The results demonstrated that the modified QuEChERS method combined with LC-MS/MS is a rapid, high, sensitive method for the analysis of nitroimidazoles and quinolones residues in honey.

scholarly journals IV. On the dynamical theory of incompressible viscous fluids and the determination of the criterion

1895 ◽  
Vol 186 ◽  
pp. 123-164 ◽  
Keyword(s):  
Singular Solution ◽  
Physical State ◽  
Theoretical Calculations ◽  
Equations Of Motion ◽  
Dynamical Theory ◽  
Viscous Fluids ◽  
Linear Functions ◽  
Incompressible Viscous Fluids ◽  
Theoretical Results

1. The equations of motion of viscous fluid (obtained by grafting on certain terms to the abstract equations of the Eulerian form so as to adapt these equations to the case of fluids subject to stresses depending in some hypothetical manner on the rates of distortion, which equations Navier seems to have first introduced in 1822, and which were much studied by Cauchy and Poisson) were finally shown by St. Venant and Sir Gabriel Stokes, in 1845, to involve no other assumption than that the stresses, other than that of pressure uniform in all directions, are linear functions of the rates of distortion, with a co-efficient depending on the physical state of the fluid. By obtaining a singular solution of these equations as applied to the case of pendulums in steady periodic motion, Sir G. Stokes was able to compare the theoretical results with the numerous experiments that had been recorded, with the result that the theoretical calculations agreed so closely with the experimental determinations as seemingly to prove the truth of the assumption involved. This was also the result of comparing the flow of water through uniform tubes with the flow calculated from a singular solution of the equations so long as the tubes were small and the velocities slow. On the other hand, these results, both theoretical and practical, were directly at variance with common experience as to the resistance encountered by larger bodies moving with higher velocities through water, or by water moving with greater velocities through larger tubes. This discrepancy Sir G. Stokes considered as probably resulting from eddies which rendered the actual motion other than that to which the singular solution referred and not as disproving the assumption.

Analysis of Stress Concentrations in Thick Cylinders With Sideholes and Crossholes

1972 ◽  
Vol 94 (3) ◽  
pp. 815-824 ◽  
Author(s):  
J. C. Gerdeen
Keyword(s):  
Stress Concentration ◽  
Stress Concentrations ◽  
Concentration Factors ◽  
Stress Concentration Factors ◽  
Experimental Values ◽  
Pressure Stress ◽  
Shrink Fit ◽  
Outside Diameter ◽  
Theoretical Results

An approximate theoretical analysis is presented for the determination of stress concentration factors in thick walled cylinders with sideholes and crossholes. The cylinders are subjected to both internal pressure and external shrink-fit pressure. Stress concentration factors are plotted as functions of the geometrical ratios of outside diameter-to-bore diameter, and bore diameter-to-sidehole diameter. Theoretical results are compared to experimental values available in the literature and results of experiments described in a separate paper.

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