Research on the application range and accuracy for series formula in the numerical calculation of SLF signal field strength

2018 ◽  
Author(s):  
Guangming Li ◽  
Yongsheng Wang ◽  
Cuihai Liu
Keyword(s):  
Numerical Calculation ◽  
Field Strength ◽  
Application Range ◽  
Signal Field

scholarly journals Variation of Low-Frequency Time-Code Signal Field Strength during the Annular Solar Eclipse on 21 June 2020: Observation and Analysis

Sensors ◽  
2021 ◽  
Vol 21 (4) ◽  
pp. 1216
Author(s):  
Xin Wang ◽  
Bo Li ◽  
Fan Zhao ◽  
Xinyu Luo ◽  
Luxi Huang ◽  
...  
Keyword(s):  
Field Strength ◽  
Solar Eclipse ◽  
Low Frequency ◽  
Signal Propagation ◽  
Normal Operation ◽  
Time Code ◽  
Long Distance ◽  
Time Service ◽  
Annular Solar Eclipse ◽  
Signal Field

Due to the occlusion of the moon, an annular solar eclipse will have an effect on the ionosphere above the earth. The change of the ionosphere, for the low-frequency time-code signal that relies on it as a reflection medium for long-distance propagation, the signal field strength, and other parameters will also produce corresponding changes, which will affect the normal operation of the low-frequency time-code time service system. This paper selects the solar eclipse that occurred in China on 21 June 2020, and uses the existing measurement equipment to carry out experimental research on the low-frequency time-code signal. We measured and analyzed the signal field strength from 20 June 2020 to 23 June 2020, and combined solar activity data, ionospheric data, and geomagnetic data, and attempted to explore the reasons and rules of the change of signal parameters. The results showed that the field strength of the low-frequency time-code signal changed dramatically within a short time period, the max growth value can reach up to 17 dBμV/m and the variation trend yielded ‘three mutations’. This change in signal field strength is probably due to the occurrence of a solar eclipse that has an effect on the ionosphere. When the signal propagation conditions change, the signal strength will also change accordingly.

Discussion on Active Television Interference Characteristic of UHV AC Transmission Line

2014 ◽  
Vol 716-717 ◽  
pp. 1139-1143
Author(s):  
Hui Chun Xie ◽  
Jian Gong Zhang ◽  
Zhuo Yi Zhou
Keyword(s):  
Field Strength ◽  
Transmission Line ◽  
Test Method ◽  
High Voltage Transmission Line ◽  
Fine Weather ◽  
Television Signal ◽  
Before And After ◽  
Ac Transmission ◽  
Signal Field ◽  
Peak Value

High-voltage transmission line corona and sparking will bring television interference (TVI). Study has been seldom executed about active TVI from HV transmission line, and much less research on UHV AC lines. Based on present literatures, this paper brings forward test method of TVI from HV transmission line. Near straight span and tension tower of Chinese UHV AC Pilot Demonstration Project, several tests about TV picture, TVI field strength, the television signal field strength before and after lines energized, has been carried out in good weather. According to observation, interference characteristics to TV picture has been analyzed. Results indicate that, with increasing distance from the outer phase, UHV single circuit TVI field strength in fine weather attenuates negative exponentially. This paper illustrates it is questionable to use CISPR quasi-peak value for assessment of interference on TV picture caused by UHV transmission line corona and sparking noise.

Study on parameters characteristics of DDGM(1,1) prediction model with multiplication transformation

2018 ◽  
Vol 8 (3) ◽  
pp. 358-365 ◽  
Author(s):  
Jie Cui ◽  
Hongyan Ma
Keyword(s):  
Numerical Calculation ◽  
Design Methodology ◽  
Quantitative Relation ◽  
Model Parameters ◽  
Content Type ◽  
Application Range ◽  
Modeling Accuracy ◽  
Characteristic Sequences ◽  
Changing Role

Purpose The purpose of this paper is to reveal the changing role of the parameters of the DDGM(1,1) model after multiple transformations in the modeling sequence. Design/methodology/approach This paper considers DDGM(1,1) model as the research object, adopts the parameter packet technique to analyze the influence of multiple transformations on the modeling accuracy of this model and discusses the quantitative relation of model parameters as multiple transformations in system’s characteristic sequences. Findings The results of numerical calculation show that the modeling accuracy of DDGM(1,1) model is not affected by multiple transformations in the characteristics sequence of systems. Originality/value The paper succeeds in realizing the properties of DDGM(1,1) model by using the method of multiple transformations, which is helpful to understand the modeling mechanism and expand the application range of DDGM(1,1) model.

Numerical Calculation of the Potential Distribution in Ion Slit Lens Systems III

1960 ◽  
Vol 15 (3) ◽  
pp. 253-259 ◽  
Author(s):  
A. J. H. Boerboom
Keyword(s):  
Numerical Calculation ◽  
Field Strength ◽  
Arbitrary Number ◽  
Potential Distribution ◽  
Computing Methods ◽  
Mutual Distance ◽  
Christoffel Transformation

In previous papers 1, 2 the potential distribution was calculated in ion slit lens systems, consisting of three slits in three parallel electrodes and satisfying certain conditions concerning their shape.In the present paper the computing methods are generalized to slit systems of an arbitrary number of electrodes, with as the only restriction, that slits broader than the distances to neighbouring slits are separated by slits, narrower than the respective distance, and that a pair of electrodes with a mutual distance smaller than their slit widths are separated from the neighbouring slits by distances greater than the respective slit widths.For slit systems, satisfying this condition the parameters are computed, necessary to perform the SCHWARZ-CHRISTOFFEL transformation. Formulae are given to compute the potential distribution and field strength. In a typical example the potential distribution and field strength are computed in the region around two parallel electrodes with broad slits compared with the distance between the electrodes.

Algebraic Form and New Approximation of Butler–Volmer Equation to Calculate the Activation Overpotential

2016 ◽  
Vol 13 (2) ◽  
Author(s):  
H. Kazemi Esfeh ◽  
M. K. A. Hamid
Keyword(s):  
Numerical Calculation ◽  
Current Density ◽  
Exchange Current ◽  
Exchange Current Density ◽  
Algebraic Operation ◽  
Algebraic Form ◽  
Application Range ◽  
Symmetry Factor ◽  
Wide Range ◽  
New Form

The Butler–Volmer equation has been widely used to analyze the electron transfer for electrochemical simulation. Although it has been broadly employed with numerous successful applications, the Butler–Volmer equation needs to be solved numerically to find the activation overpotential, which results in the increase of the calculation difficulties. There are also some parameters in Butler–Volmer equation such as exchange current density and symmetry factor that are not always known parameters. In order to avoid the latest mentioned limitation and the numerical calculation which is time consuming and for simplification, there are some approximation equations such as Tafel, linear low polarization, and hyperbolic sine approximation. However, all these equations are only applicable in a specific range of current density or definite condition. The aim of this paper is to present a new form of Butler–Volmer equation using algebraic operation to calculate activation overpotential. The devised equation should be accurate, have a wide application range, able to remove any numerical calculation, and be useful to find exchange current density. In this research, a new form of Butler–Volmer equation and a new approximation equation (called K–J equation) have been successfully derived. The comparison result shows that the new derived form is exactly equal to the Butler–Volmer equation to calculate the activation overpotential, and it removed the necessity of numerical calculation to find the activation overpotential. In addition, the K–J approximation has a good agreement with Butler–Volmer equation over a wide range of current density and is applicable to predict the activation loss.

Quantifying Field-Induced Contrast Effects in Photoelectron Emission Microscopy

2003 ◽  
Vol 803 ◽  
Author(s):  
K. Siegrist ◽  
V. W. Ballarotto ◽  
E. D. Williams
Keyword(s):  
Numerical Calculation ◽  
Field Strength ◽  
Titanium Surface ◽  
Full Width ◽  
Contrast Effects ◽  
Applied Bias ◽  
Photoelectron Emission ◽  
Lateral Field ◽  
Emission Microscopy ◽  
Photoelectron Emission Microscopy

ABSTRACTSamples consisting of electrically isolated titanium lines fabricated on a titanium surface were used to quantify voltage-induced contrast effects in photoelectron emission microscopy (PEEM). Induced contrast effects were observed to extend 6 μm for a -5 V bias applied to a 303 nm tall raised line. We therefore explored, via numerical calculation, the spatial extent of the perturbation to the PEEM accelerating field caused by the bias applied across the step height. The intensity full width at half minimum agreed well with the calculated width defined by the 10% level of lateral field strength. For a line 550 nm tall, a correspondence was found for a calculated width defined by a 5% lateral field strength. It was observed that neighboring structures a few μm away affected the image contrast, for sufficiently strong applied bias. This suggests that effects can easily be induced at distances of 0.5 μm for modest applied voltages, as has been previously observed for structures buried under oxide layers 0.5 μm thick [1].

On the Configuration of the Magnetic Field of β CrB

1976 ◽  
Vol 32 ◽  
pp. 613-622
Author(s):  
I.A. Aslanov ◽  
Yu.S. Rustamov
Keyword(s):  
Magnetic Field ◽  
Field Strength ◽  
Radial Velocity ◽  
Magnetic Field Strength ◽  
Complex Shape ◽  
Rotation Period ◽  
Field Variation ◽  
Magnetic Field Variation ◽  
Secular Variations ◽  
The Magnetic Field

SummaryMeasurements of the radial velocities and magnetic field strength of β CrB were carried out. It is shown that there is a variability with the rotation period different for various elements. The curve of the magnetic field variation measured from lines of 5 different elements: FeI, CrI, CrII, TiII, ScII and CaI has a complex shape specific for each element. This may be due to the presence of magnetic spots on the stellar surface. A comparison with the radial velocity curves suggests the presence of a least 4 spots of Ti and Cr coinciding with magnetic spots. A change of the magnetic field with optical depth is shown. The curve of the Heffvariation with the rotation period is given. A possibility of secular variations of the magnetic field is shown.

Improvements in the electron probe forming capabilities and x-ray hole counts in the Philips TEM

1983 ◽  
Vol 41 ◽  
pp. 376-377
Author(s):  
Richard L. McConville
Keyword(s):  
Field Strength ◽  
Electron Probe ◽  
Spherical Aberration ◽  
Focal Length ◽  
Objective Lens ◽  
Parallel Beam ◽  
Tilt Axis ◽  
X Ray ◽  
Small Probe ◽  
Specimen Height

A second generation twin lens has been developed. This symmetrical lens with a wider bore, yet superior values of chromatic and spherical aberration for a given focal length, retains both eucentric ± 60° tilt movement and 20°x ray detector take-off angle at 90° to the tilt axis. Adjust able tilt axis height, as well as specimen height, now ensures almost invariant objective lens strengths for both TEM (parallel beam conditions) and STEM or nano probe (focused small probe) modes.These modes are selected through use of an auxiliary lens situ ated above the objective. When this lens is on the specimen is illuminated with a parallel beam of electrons, and when it is off the specimen is illuminated with a focused probe of dimensions governed by the excitation of the condenser 1 lens. Thus TEM/STEM operation is controlled by a lens which is independent of the objective lens field strength.

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