Calculation Of Field Strength Research Articles

Crystal field optimization, luminescence enhancement and thermal stability of novel K2NaAl0.4Ga0.6F6:Mn4+ solid solution red phosphor for high-performance warm WLED

Mn4+-doped fluoride phosphors have important application value in the background light and WLED lighting fields. Therefore, the synthesis of efficient and stable Mn4+-doped red phosphor is of great application value. In this study, a series of red-emitting K2NaAl1-yGayF6:xMn4+ (y = 0, 0.2, 0.4, 0.6, 0.8 and 1) (x = 0.01, 0.03, 0.05, 0.07 and 0.09) solid solution phosphors are successfully synthesized by simple coprecipitation method. The synthesis strategy of simple crystal structure optimization is proposed to realize simultaneously the crystal field optimization, luminescence enhancement and thermal stability of red phosphor. The calculation and theoretical analysis of crystal field strength are used to prove that solid solution matrix K2NaAl0.4Ga0.6F6 is the most ideal matrix material. X-ray powder diffraction, energy-dispersive X-ray spectrometer and scanning electron microscope are employed to determine the crystal structure, composition and morphology of all samples. Optical properties are characterized using excitation spectra, emission spectra and fluorescence lifetime curves. Moreover, the CIE coordinates of red-light show that the phosphor has low correlated color temperature and excellent color purity. Intriguingly, the as-prepared K2NaAl0.4Ga0.6F6:Mn4+ phosphor possesses admirable thermal quenching behavior and color stability at high temperature. At a temperature of 423 K, the photoluminescence intensity can be maintained at 52 % of the original intensity (298 K). The activation energy, the chromaticity shift and chromaticity coordinate variation are also systematically calculated. More importantly, A high-performance warm WLED with low correlated color temperature (CCT = 3982 K) and high color rendering index (Ra = 93.7) is achieved by using K2NaAl0.4Ga0.6F6:Mn4+ as a red-emitting material. These results demonstrate that K2NaAl0.4Ga0.6F6:Mn4+ red phosphor provides a novel choice for the warm WLED required for indoor lighting.

Construction of Br-Cu2O@NiFe-LDHs Z-scheme heterojunction and photocatalytic degradation of catechol

Facet regulation and construction of heterojunctions are important means to enhance the photocatalytic performance of single-phase materials. In this paper, the facet index of Cu2O was changed through Br doping, and then a Br doped Cu2O@NiFe-LDHs Z-scheme heterojunction (BC@LDHs) was constructed for photocatalytic degradation of catechol. The optimal conditions for photocatalytic degradation reaction were explored; the kinetic and thermodynamic parameters of the reaction, as well as the stability and reusability of the material were studied. Under optimal reaction conditions, the photocatalytic degradation of catechol can reach up to 95.68 % by BC@LDHs, which is much higher than that of single-phase materials and Cu2O@LDHs. By combining experiments and theoretical calculations, the intrinsic reasons and mechanisms for Br doping to enhance the photocatalytic degradation performance of BC@LDHs Z-scheme heterojunctions were fully explored from the perspectives of band structure and oxygen adsorption, determination of built-in electric field in Z-scheme heterojunctions, calculation of built-in electric field strength and bulk charge separation efficiency. This work proposes the insights that using Br doping to alter exposed facets and regulate the strength of the built-in electric field in Br-Cu2O@NiFe-LDHs heterojunctions, thereby promoting its efficient photocatalytic degradation.

Calculation of temperature dependent critical field strength of mixtures containing C5-FK, CO 2 and O 2

Calculation of temperature dependent critical field strength of mixtures containing C5-FK, CO ₂ and O ₂

Development of a novel signal restoration algorithm to eliminate the distorted components in space charge measurement excited by femtosecond laser irradiation

AbstractFor the space charge measurement method with optical excitation for electrical insulation, the distortion of the excitation laser on the measurement signal and the accumulation of space charge have not been discussed before. Both experiment and simulation results show that three types of distorted components introduced by optical excitation can lead to distortion of the upper interface signal. Further, the factors causing distortion of the measured signal and the formation mechanism are analysed. A virtual electrode potential compensation method and a distorted component extraction method are proposed. Meanwhile, an attenuation restoration and charge conversion correction factor is introduced, leading to a novel signal processing algorithm adapted to space charge optical measurement methods. Compared with the traditional algorithm, the novel algorithm has an error of less than 1% in the calculation of charge and electric field strength, with an increase in accuracy of 47.7% and 9.81%, respectively. By applying the novel restoration algorithm, the comparison shows that the space charge accumulation does not change significantly under laser irradiation, verifying the reliability of the optical excitation. The given algorithm can provide a theoretical and technical foundation for the realisation of the optical measurement method for space charge.

Analysis and modeling of radio propagation fading characteristics in tunnel construction

With the development of underground rail transit, the concept of intelligent tunnel construction has been proposed and promoted. High-quality networking during tunnel construction is a prerequisite for this, making it highly urgent to establish networking during tunnel construction. When studying intra-tunnel networking, it is necessary to consider the propagation characteristics of radio waves in the tunnel. In this paper, according to the actual needs of engineering in tunnel construction and the characteristics of tunnel scenes, an improved ray tracing method is proposed, which considers the type and installation position of antennas, transceiver frequency band and power in channel modeling, and proposes a field strength calculation method under different coordinate systems according to the characteristics of straight and curved segments during tunnel construction. In addition, the propagation characteristics of radio waves in dynamic tunnel construction scenarios are quantitatively analyzed. In this paper, by establishing antenna diagram, two-dimensional and three-dimensional models of tunnels, the computer simulation method is applied to compare with the improved algorithm, and the results have good consistency, in addition, the improved algorithm does not require a lot of modeling work in the early stage, and has high applicability and portability. Not only that, this paper also makes actual measurements of the subway under construction in Zhengzhou, China in different scenarios, and verifies the effectiveness of the method.

Магнитное поле многовитковой цилиндрической катушки с ферромагнитным сердечником в непосредственной близости от металлических конструкций в задаче поиска людей под завалами в шахтах

Some aspects of the low-frequency magnetic field propagation in heterogeneous medium in mines are discussed in the paper. The theoretical model for calculation of magnetic field distribution in case of the parallel axis of transmitting antenna and bulk metal is developed. Metal structures are rail tracks, magnetic antenna is multiturn cylindrical coil with ferromagnetic core. Magnetic field according to proposed models principle in several stages using the method of integral equations was numerical calculated. This method of calculation of magnetic field in considered inhomogeneous space is based. The calculations of magnetic field strength of the multiturn cylindrical coil with ferromagnetic core in nearby proximity and at various distances from bulk metal were carried out. The possibility of use of low-frequency magnetic field attenuation for people search under avalanches was proved.

Discovery of an extremely intermittent periodic radio source

ABSTRACT We report the serendipitous discovery of an extremely intermittent radio pulsar, PSR J1710−3452, with a relatively long spin period of 10.4 s. The object was discovered through the detection of 97 bright radio pulses in only one out of 66 epochs of observations spanning almost three years. The bright pulses have allowed the source to be localized to a precision of 0.5 arcsec through radio imaging. We observed the source location with the Swift X-ray telescope but did not detect any significant X-ray emission. We did not identify any high-energy bursts or multifrequency counterparts for this object. The solitary epoch of detection hinders the calculation of the surface magnetic field strength, but the long period and the microstructure in the single-pulses resembles the emission of radio-loud magnetars. If this is indeed a magnetar, it is located at a relatively high Galactic latitude (2.9°), making it potentially one of the oldest and the most intermittent magnetars known in the Galaxy. The very short activity window of this object is unique and may point towards a yet undetected population of long period, highly transient radio emitting neutron stars.

Calculation of Magnetic Field Strength from a Semi-Infinite Cylinder Placed in an Arbitrary External Field

Calculation of Magnetic Field Strength from a Semi-Infinite Cylinder Placed in an Arbitrary External Field

Research on Induction Measurement of Operators Approaching Charged Bodies in Complex Operation Scenarios

Aiming at the uneven distribution of the electric field and the difficulty in achieving low false alarms for operators approaching charged bodies in the complex operating environment in the power system, a mask region convolutional neural network (MR-CNN) based complex operation scene recognizer is first constructed in this paper to perform image feature extraction, target box regression, and classification training. Secondly, a simulated annealing-based mirror-image charge method is proposed to calculate the electric field distribution characteristics. The simulated annealing algorithm is used to optimize the number of charges of the mirror-image charges method to minimize the weighted sum of the calculation error and the electric field strength calculation time. Finally, the feasibility and effectiveness of the proposed algorithm are verified through simulation experiments.

Computational Numerical Analysis of a Magnetic Flux Permanent Magnet with Different Shape for The Development of a Hybrid Generator

A hybrid generator is one of the attempts to reduce carbon emissions in electricity generation, as it could replace the combustion system currently used in generator sets to generate electricity while increasing carbon emissions. In the hybrid generator system, Lenz's rule of electromagnetic induction is applied in reverse by using a relay to change the polarity of the solenoid coil's electric current. The permanent magnet in the solenoid coil generates mechanical energy (motion) and thereby moves the generator engine, since the permanent magnet is connected to the generator engine via the crankshaft. The objective of this study is to determine and compare the behaviour of N55, N52, N42, N42SH, and samarium-cobalt permanent magnets for the magnet system. The objective of this study is also to find a suitable permanent magnet for use in the magnet system to increase the power generation efficiency. A simple model is simulated to achieve the desired result, including magnetic flux density inside and around the magnets, magnetic field strength calculation, and applied force. The simulations and analysis are performed using ANSYS R19 software and finally all the data are recorded and compared to select the best magnet and develop a prototype. The permanent magnet inside the solenoid plays an important role in the hybrid generator and it is crucial to choose the suitable permanent magnet to increase the efficiency of power generation. From the data, Alliance N-55 permanent magnet has the highestmagnetic force of 131.57 N for 1 mm because it has significantly higher magnetic flux density, magnetic flux intensity and magnetic force.

Active heat transfer enhancement by interface-localized liquid dielectrophoresis using interdigitated electrodes

We introduced an active heat transfer control between graphene and water using interdigitated electrodes (IDEs). Oppositely charged co-planer electrodes embedded on a graphene surface created a non-uniform electric field. Resulted interface localized liquid dielectrophoresis (LDEP) perpendicular to surface enhanced the water/graphene coupling and decreased interfacial thermal resistance (ITR) substantially. We correlated the theoretical calculations of average electric field strength near surface with Kapitza values measured at corresponding electrode configurations. We obtained a unified linear variation of Kapitza as a function of average electric strength independent of electrode size and charge. By increasing the electric field strength, we measured up to 96% decrease of Kapitza near electrodes. Since the IDEs generated electric field was only interface localized, it required lower electrode charges than any parallel-plate capacitor systems. We showed that ITR remains effective in heat transfer behavior for systems as big as 100nm such that interface localized electric field can at least increase the heat removal 50% by eliminating the ITR from both graphene/water interfaces of a channel system. By converting hydrophobic few-layer graphene to super-hydrophilic condition with ultra-low Kapitza, current results are important for graphene-based materials considered for the solution of the thermal management problem of current and next generation micro/nano-electronics.

Analysis of Effect Electric Field Strenght on Safe Distance Below Main Substation Busbar 150 kV

This research is to analyze the effect of electric field strength on the safe distance under the 150kV substation busbar. The research was conducted at 150 kV substation Rancaekek, substation Rancakasumba, substation Cikasungka. The electric field exposure threshold value according to SNI, ICNIRP, IRPA/INIRP and WHO is 10kV / m for the working community. The lowest distance of the busbar conductor to the ground surface is 7.5m. Measurements and calculations of transverse electric field strength from busbar 1 to busbar 2. The height of the test point is 0 m to 2.3 m from the ground surface. From the results of the calculation of the electric field, strength obtained that the shortest minimum safe distance is 7.48 m, while the highest minimum safe distance is 7.88 m. From the results of the measurements of the electric field From the results of measurements of electric field strength obtained that the fastest duration of electric field exposure was 4.42 hours while the longest electric field exposure duration was 5.75 hours. From the calculation of the electric field, strength obtained that: the fastest duration of electric field exposure is 7.56 hours while the longest duration of electric field exposure is 7.91 hours.

The magnetic field of a three-phase power line with an ordinary and triangular arrangement of wires

Power lines are sources of magnetic fields, which requires attention to ensure safety for people and to consider electromagnetic compatibility. In this article the nondimensional form expressions for calculation of magnetic field strength of a three-phase line with an ordinary and triangular arrangement of wires were obtained what makes it possible to calculate the necessary distance to the core of the line if the maximum permissible level of magnetic field strength is provided. The approximate expression of magnetic field strength at large distance from the line was considered. It is valid with the measurement accuracy less than 1%, which shows the proportion between magnetic field strength and distances between wires and inverse proportion of square distance to the wire core. It was determined that the triangular arrangement of three-phase line wires has lower magnetic field strength than the arrangement of wires in row due to more compact arrangement of wires.

The approximate calculation of 2D field strength with a Coulomb potential by using multipole expansion

The necessary formulae are derived for approximate computation of the Coulomb-type potential and the field strength, generated by system of particles in 2D case. On the one hand, these formulae represent the multipole expansion in which monopole, dipole, quadrupole and octupole terms are taken into account that allows for computing the potential and the field strength, generated by set of the charges with rather high accuracy. On the other hand, polynomial expansions of the obtained formulae are derived up to the cubic terms with respect to the observation point coordinates, which make it possible to compute the field strength at closely located points approximately. The expressions are derived that permit one to compute the multipole moments for the system of charges, which consists of smaller subsystems. Such formulae are required in tree-codes when the hierarchical (tree-type) structure of geometrical regions is introduced in the region of the initial system of the charges. In particular case these expressions allows for changing of the reference point of multipole moments computation (multipole moments shifting). The test problem is considered for rather small number of the charges, which shows the dependency of the relative error of the field strength reconstruction on the type of multipole expansion and number of considered terms in the Taylor expansion.

MODELING OF THE ELECTRIC FIELDS IN THE VICINITY OF THE CONDUCTIVE LIGHTNING RODS

The aim of the work is to develop a method for more accurate calculation the electric field (EF) distribution in the systems with conducting lightning rods, ensuring that the electric field strengths and potentials can be found at the grid spatial step proportional to the rod length and not to its radius. Methodology: a method of the electric field calculation in the vicinity of conducting rods with a large ratio of length to radius: more than 102–103 is described. The proposed method is based on the finite integration technique and usage of information on the nonlinear decrease of the EF strengths and potentials in the directions perpendicular to the rod axis. Results: it is shown that the best match with analytical solutions can be achieved by obtaining the difference coefficients at the nodes surrounding the rod with the help of integrating expressions for the EF strength of a conductive ellipsoid upon electric potential over the computational grid cell surfaces. Practical value: as a result of the proposed method usage, it become possible more accurate calculation of the electric field strength in the zone around a rod under potential or a rod in a homogeneous EF when applying a grid, the step of which is comparable with its length, not its radius. Originality: usage of the proposed method for calculation of the EF strength in the vicinity of the conducting rods, taking into account nonlinear character of the EF strength and potential decrease in the close vicinity of the rod with the help of analytical expressions for the EF of an elongated conducting ellipsoid upon electric potential, reduces relative errors of the EF strength calculation in the zone around the rod and above its tip from 27 % to 3 % and less. In this case, a spatial step is chosen proportional to the length of the rod, and not to its radius. An example of the electric field strength calculation in lightning storm conditions is presented.

Study on Calculation and Mitigation Measurements of Power Frequency Electric Field Strength of Residential Buildings Near High Voltage AC Transmission Lines

In this paper, based on the charge simulation method, the distorted electric field of a 500kV transmission line adjacent to the residential building is simulated and compared with the field test results. The calculated value is close to the measured value, which indicates that the distorted power frequency electric field calculation based on the charge simulation method has engineering application accuracy. Furthermore, the requirements of the height of the 500kV transmission line and the minimum horizontal distance of the adjacent residential buildings are determined by the charge simulation method. Two feasible power frequency electric field mitigation measures are proposed for the design of the transmission line.

Offshore Electromagnetic Spectrum Distribution Prediction Model Based on Ray Tracing Method and PM Wave Spectrum

Electromagnetic spectrum distribution prediction is the basis for the development of wireless communication technology. Due to the high randomness of the rough sea surface, it is difficult to accurately predict the offshore electromagnetic spectrum distribution. We present a prediction model of offshore electromagnetic spectrum distribution based on ray tracing method and Pierson-Moskowitz (PM) wave spectrum model. Based on the antenna attitude and the antenna directional pattern, the field strength calculation formulas of the electromagnetic wave sight line ray (SLR) propagation and the electromagnetic wave reflecting line ray (RLR) propagation off the sea surface are established. As the sea surface and the antenna attitude change, the effective rays from the transmitting antenna to the receiving antenna also change. This paper focus on the electromagnetic spectrum distribution prediction by calculating the effective angle (EA) of the transmitting antenna. We relate the EA to the antenna tilt angle and the antenna directional pattern, and combine the PM wave spectrum to establish the offshore electromagnetic spectrum distribution prediction models. Finally, we simulated the electromagnetic spectrum distribution prediction based on specific PM wave spectrum data.

Module of Elements for Beam Injection into the Booster of the NICA Accelerator Complex

This paper presents the project of the electrostatic septum and electric kicker plates for beam injection into the booster of the NICA accelerator complex. The results of calculations of electric field strength in the elements are given.

Calculation of electric field strength in the ionospheric F-region

In this study, we have calculated the electric field strength, Ey, of a plane electromagnetic wave with frequency, ?, propagation along z-axes and the polarized y-axes in 1-D by using Wentzel, Kramers, and Brillouin method for both with and without collision conditions in ionospheric F-region with regard to seasonal and local time. Also, the refractive index of ordinary wave and attenuation factor was computed for collision and collision-free conditions. When the collisions were calculated in the F-region of the ionosphere, it was observed that the electric field strength decreased for all seasons and Ey increased between 275-400 km altitudes encountering approximately hmF2 ?the peak of F2? for the accepted conditions.

Influence of measurement uncertainty of overhead power line conductor heights on electric and magnetic field calculation results

In this paper, it is analyzed how the measurement uncertainty of the overhead power line conductor heights influences the calculation results of electric field strength and magnetic flux density in the vicinity of the line. It is assumed that the conductor heights have been determined by measurements, by using a laser telemeter which has a certain measurement error. The laser telemeter measures the distance to the target object and inclination, and based on these two quantities and the manually entered data concerning the height on which the telemeter is placed it calculates the height of the target object, as well as the horizontal distance to it. Each of these measured quantities (distance and inclination) is measured with a defined error. The error of the height measurement has to be calculated based on the two defined errors. The procedure for calculating these errors is explained in detail in the paper, and the errors referring to typical heights of the overhead power line conductors are determined. If the calculations of electric field strength and magnetic flux density are made for the conductor heights with the established deviation in relation to the real heights, this will reflect on the calculated field results. The influence of this factor on the results of the electric field strength and magnetic flux density calculations is thoroughly analyzed.