scholarly journals Propagation of video pulse signals in dissipative media

2021 ◽  
Vol 2021 (1) ◽  
Author(s):  
O.A. Gulevich ◽  
◽  
L.B. Volkomirskaya ◽  
I.V. Mingalev ◽  
Z.V. Suvorova ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Pulse Signal ◽  
Data Interpretation ◽  
Echo Signal ◽  
Electromagnetic Pulses ◽  
Nanosecond Duration ◽  
Video Pulse ◽  
Dissipative Media ◽  
Temporal And Spatial ◽  
Gradient Change

The results of the numerical solution of the problem of propagation of an electromagnetic video pulse signal of nanosecond duration in a dissipative medium are presented for use in the deep georadar data interpretation. Based on the developed scheme for integrating Maxwell's equations, the results of numerical modeling of the propagation of electromagnetic pulses of various shapes without approximations, usually used in the traditional solution of GPR problems, including the separation of temporal and spatial variables of the electromagnetic field and neglect of the rapid field change in comparison with the processes occurring in the medium, are obtained. The influence of the pulse shape on the shape of the electromagnetic echo signal is considered for various models of the medium close to real conditions, including those with a gradient change in electrical conductivity and permittivity. The influence of the distribution of electrical conductivity of the medium is studied.

A Method of Receiver Circuit in High-Duplicate Pulse Lased Range Finding’s Design and Analysis

2013 ◽  
Vol 631-632 ◽  
pp. 1051-1054
Author(s):  
Zhang Le ◽  
Zhi Yong An ◽  
Yong Ping Hao ◽  
Qin Dai ◽  
Ye Qiu Li
Keyword(s):  
High Speed ◽  
Dynamic Range ◽  
Pulsed Laser ◽  
Pulse Signal ◽  
Laser Ranging ◽  
Echo Signal ◽  
Voltage Comparator ◽  
Range Finding ◽  
Signal Error ◽  
Finding Method

In this paper, the two main reasons are introduced such as great varying range of echo signal power and pulse signal error, which affect the pulse laser ranging accuracy and analyzed on the base of the pulsed laser range finding method. For them, the methods are provided that the AGC technology in the receiving circuit is adopt to extend the dynamic range of the receiver, and gain the high precision receiving pulse signal by using high-speed voltage comparator. Then the problems of great varying range of echo signals caused by different measuring distance and contacting the timing circuit are resolved efficiently.

RF Pulse Signal Study in the SAW Delay-Line Sensor

2013 ◽  
Vol 655-657 ◽  
pp. 705-709 ◽  
Author(s):  
Tian Li Li ◽  
Gang Xu ◽  
Li Cun Fang
Keyword(s):  
Pulse Width ◽  
Delay Line ◽  
Pulse Signal ◽  
Design Parameters ◽  
Transmission Characteristics ◽  
Echo Signal ◽  
Saw Sensor ◽  
Rf Pulse ◽  
Pulse Echo ◽  
Selection Of

The SAW delay-line sensor can obtain the energy of the RF pulse query signal through the wireless method. The RF pulse echo signal of the SAW delay-line sensor is significant effected by the different query pulse width of the RF pulse query signal, which is directly related to the sensor precision. The size of the IDT and reflectors, the distance between the IDT and reflector, and the distance among the different reflectors can affect the selection of the RF pulse query signal. The selection method of the query pulse width is discussed through the theoretical analysis and experimental analysis according to the SAW delay-line transmission characteristics. The query pulse width can be calculated directly through the design parameters of the SAW sensor.

scholarly journals Growth and production of colored fiber cotton (Gossypium hirsutum L.) subjected to salt stress and potassium fertilization

2020 ◽  
pp. 1595-1600
Author(s):  
Jéssica Dayane Capitulino ◽  
Carlos Alberto Vieira de Azevedo ◽  
Geovani Soares de Lima ◽  
André Alisson Rodrigues da Silva ◽  
Luana Lucas de Sá Almeida Veloso ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Irrigation Water ◽  
Negative Effects ◽  
Saline Irrigation ◽  
Colored Cotton ◽  
Soil Irrigation ◽  
Temporal And Spatial ◽  
Four Levels ◽  
Different Levels ◽  
Sensitive Variable

Temporal and spatial variation of rainfall in semiarid regions may lead to an increase in the concentrations of salts present in irrigation water, and it is necessary to adopt techniques to reduce the negative effects of salts on plants. Thus, the present study aimed to evaluate the growth and production of colored cotton cv. BRS Topázio as a function of irrigation using water with different levels of salinity and potassium doses. The experiment was carried out in pots adapted as lysimeters under greenhouse conditions, using a non-saline Neossolo Regolítico (Entisol) of sandy texture. The experimental design was randomized blocks, with 4 replicates, with treatments distributed in a 4 x 4 factorial scheme, corresponding to four levels of saline irrigation water electrical conductivity (1.5; 3.0; 4.5 and 6.0 dS m-1) and four potassium doses (50; 75; 100 and 125% of the recommendation), with a dose of 100% corresponding to 150 mg K2O per kg-1 of soil. Irrigation using water of electrical conductivity (saline) above 1.5 dS m-1 negatively affected the growth and production of cotton cv. BRS Topázio, and cotton seed weight was the most sensitive variable. Potassium doses above 50% of the recommendation in interaction with salinity reduced the height and leaf area of cotton cv. BRS Topázio.

THE INTERPRETATION OF ELECTROMAGNETIC REFLECTION DATA IN GEOPHYSICAL EXPLORATION PART II.—METALLIC MODEL EXPERIMENTS

Geophysics ◽  
1952 ◽  
Vol 17 (4) ◽  
pp. 806-826 ◽  
Author(s):  
W. Jacque Yost ◽  
R. L. Caldwell ◽  
C. I. Beard ◽  
C. D. McClure ◽  
E. N. Skomal
Keyword(s):  
Electrical Conductivity ◽  
Pulse Shape ◽  
Salt Dome ◽  
Geophysical Data ◽  
Experimental Check ◽  
Virtual Image ◽  
Electromagnetic Pulses ◽  
Model Experiments ◽  
Reflection Data ◽  
The Earth

A metallic model of a horizontally stratified section of the earth’s crust has been constructed to provide information of considerable value in the interpretation of geophysical data. Modeling considerations and experimental arrangements are discussed in detail for a system employing loops of wire as transmitter and receiver for the study of propagation of electromagnetic energy in and on a semi‐infinite conductor. An experimental check of the theory given in Part I (Yost, 1952) has been made for the case of a semi‐infinite conducting medium underlying a semi‐infinite insulator. Discontinuities in electrical conductivity within such a medium have been shown to reflect electromagnetic pulses back to the surface. A detailed study of the shape of these pulses from single reflectors has been made showing that certain characteristics of the pulse shape can be correlated with the depth and nature of the reflecting horizon. The reflected signals can be approximately described by considering the discontinuities as reflectors which, in turn, can be replaced by virtual “image” oscillators in a homogeneous structure. The extent to which this approximation holds is discussed in the light of experiments with the model. An example is given of the use of a non‐concentric loop arrangement for geophysical profiling of a limited reflector, such as a salt dome. Finally, data are given to show the agreement between model signals and field results obtained from a known resistivity contrast in the earth.

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