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Showing papers on "Field (physics) published in 2022"


Journal ArticleDOI
TL;DR: In this article, a mixture stress gradient theory of elasticity is conceived via consistent unification of the classical elasticity theory and the stress gradients theory within a stationary variational framework, and the boundary-value problem associated with a functionally graded nano-bar is rigorously formulated.
Abstract: The mixture stress gradient theory of elasticity is conceived via consistent unification of the classical elasticity theory and the stress gradient theory within a stationary variational framework. The boundary-value problem associated with a functionally graded nano-bar is rigorously formulated. The constitutive law of the axial force field is determined and equipped with proper non-standard boundary conditions. Evidences of well-posedness of the mixture stress gradient problems, defined on finite structural domains, are demonstrated by analytical analysis of the axial displacement field of structural schemes of practical interest in nano-mechanics. An effective meshless numerical approach is, moreover, introduced based on the proposed stationary variational principle while employing autonomous series solution of the kinematic and kinetic field variables. Suitable mathematical forms of the coordinate functions are set forth in terms of the modified Chebyshev polynomials, satisfying the required classical and non-standard boundary conditions. An excellent agreement between the numerical results of the axial displacement field of the functionally graded nano-bar and the analytical solution counterpart is confirmed on the entire span of the nano-sized bar, in terms of the mixture parameter and the stress gradient characteristic parameter. The effectiveness of the established meshless numerical approach, demonstrating a fast convergence rate and an admissible convergence region, is hence ensured. The established mixture stress gradient theory can effectively characterize the peculiar size-dependent response of functionally graded structural elements of advanced ultra-small systems.

37 citations


Journal ArticleDOI
TL;DR: In this article, an approach that allows detecting all three components of the residual magnetic field inside shielding, based on the electron paramagnetic resonance (EPR) of spin-polarized K atoms, is presented.

19 citations



Journal ArticleDOI
TL;DR: In this article, a stochastic approach for modeling and analysing the transients due to the users' water consumptions in a real water distribution system is presented, based on field measure.
Abstract: A stochastic approach for modeling and analysing the transients due to the users’ water consumptions in a real water distribution system is presented. The analysis is based on field measure...

10 citations


Journal ArticleDOI
TL;DR: A solution algorithm based on the combination of scalar and vector fields is proposed, which indicates that the standard deviation of prototype instrument in magnetic direction was close to that of declination–inclination magnetometer, whereas its standard deviation in Z-component was better than that of a commercial fluxgate magnetometer.
Abstract: The diversity of magnetic field information obtained in marine geomagnetic measurements is of great relevance to defining detailed features of the targets. In this article, a solution algorithm based on the combination of scalar and vector fields is proposed. The magnetic direction of the geomagnetic field was obtained by repeatedly applying bias fields, and the multiparameter integrated measurement is realized based on the geometric relationship of the geomagnetic parameters. To make an instrument feasible for undersea measurement, a miniaturized multiparameter magnetometer was constructed within the limited space of a pressure tank, using an Overhauser scalar sensor and a spherical coil for generating bias fields. Test platforms were built to evaluate the scalar sensor and spherical coil. Results from a nonmagnetic laboratory showed that the expanded uncertainty of the scalar sensor was 0.11 nT, whereas the magnetic field generated by the spherical coil had 97% uniformity and completely engulfed the scalar sensor. Moreover, field experiments indicated that the standard deviation of prototype instrument in magnetic direction (3 $^{\prime \prime }$ ) was close to that of declination–inclination magnetometer, whereas its standard deviation in Z -component of 0.24 nT was better than that of a commercial fluxgate magnetometer. It also had markedly better measurement stability, with no temperature drift.

8 citations


Journal ArticleDOI
TL;DR: In this article, the exchange interactions between Ho-Dy and Ho-Ho were set as free parameters and adjusted to match the experimental results, and the heat capacity of polycrystalline materials in non-zero magnetic fields was satisfactory reproduced by using the average of multiple magnetic field directions with respect to the crystallographic coordinate system.

7 citations


Journal ArticleDOI
TL;DR: In this article, the authors theoretically study the optical properties of a hybrid structure consisting of a metal nanoparticle (MNP) and an asymmetric double semiconductor quantum dot (SQD) molecule, which are coupled together, via long-range Coulomb interaction.
Abstract: We theoretically study the optical properties of a hybrid structure consisting of a metal nanoparticle (MNP) and an asymmetric double semiconductor quantum dot (SQD) molecule, which are coupled together, via long-range Coulomb interaction. We derive and solve numerically the relevant density-matrix equations and use electromagnetic calculations to evaluate the energy absorption rate of the MNP and the asymmetric double SQD molecule, separately, as well as, the total absorption rate for the entire hybrid structure, as a function of the energy of an applied electromagnetic field , for two different applied field polarization directions. We also investigate the impact of the applied field intensity and the electron tunnelling coupling rate on the spectral profiles, for several values of the interparticle distance. The Autler-Townes splitting and double nonlinear Fano effects are obtained in the absorption spectra of the asymmetric double SQD molecule, the MNP and the total system.

6 citations



Journal ArticleDOI
TL;DR: In this paper, the free vibrations of transversely isotropic nonlocal electro-magneto thermoelastic hollow cylinder with voids are addressed in the preview of generalized thermelasticity, and the governing equations and the constitutive relations are transformed into coupled ordinary differential equations by applying time harmonic variations.
Abstract: The free vibrations of transversely isotropic nonlocal electro-magneto thermoelastic hollow cylinder with voids are addressed in the preview of generalized thermoelasticity. The governing equations and the constitutive relations are transformed into coupled ordinary differential equations by applying time harmonic variations. The boundary conditions of the outer and the inner surfaces of the hollow cylinder are considered to be traction free, no change in voids volume fraction and thermally insulated/isothermal temperature field. The analytical results for frequency equations are presented and validated with existing literature. To explore the free vibration analysis from the considered boundary conditions, the numerical iteration method has been generated to create data by using MATLAB software tools. The obtained analytical results are represented graphically with the assistance of numerical computations and simulations in absence/presence of magnetic field for nonlocal/local thermoelastic materials. To verify the elastic nonlocal effects in different models of thermoelasticity, the field functions are represented graphically with and without magnetic field effects. The study may find applications in the field of seismology for drilling and mining in the earth's crust appliances, lightweight armors, geophysics, acoustics, and oil prospecting etc.

5 citations


Journal ArticleDOI
Chen Li1, Xiaoming Xu1, Hao Hu1, Nan Mei1, Yi Yang1 
01 Feb 2022
TL;DR: In this article, a multiphase, 3D PEMFC model with serpentine flow channel is developed to rank structural parameters according to the degree of influence on fuel cell performance.
Abstract: The electrochemical reaction inside a high-power fuel cell generates a lot of heat. Excessive heat affects the performance of the membrane, so it is necessary to introduce coolant. The main objective of coolant is regulating the temperature of relatively high-power proton exchange membrane fuel cell (PEMFC) stacks efficiently. The coolant channel has a great influence on the performance of PEMFC. In this work, a multiphase, 3D PEMFC model with serpentine flow channel is developed. In order to rank structural parameters according to the degree of influence on fuel cell performance, this study analyzed the current density, O2 mass fraction, and the distributions of temperature based on an orthogonal test scheme with three factors and three levels. The results show that rib width between the reactant flow channel and the cooling channel has the greatest influence on the current density, and gas flow channel width has the least influence.

4 citations


Book ChapterDOI
01 Jan 2022
TL;DR: In this paper, it has been shown how evanescent photons, produced in highly coherent excited quantum states of liquid water, could be considered in order to perform quantum computations in a completely novel and still unexplored fashion by considering the formation of excited coherent quantum domains in liquid water.
Abstract: It has been shown how evanescent photons, produced in highly-coherent excited quantum states of liquid water, could be considered in order to perform quantum computations in a completely novel and still unexplored fashion by considering the formation of excited coherent quantum domains in liquid water, associated to cold vortex of quasi-free electrons, and their interaction through the mutual exchange of virtual evanescent photons, by quantum tunnel effect. Furthermore, the use of metamaterials to enclose water molecules, in order to form suitable waveguide for the evanescent photons generated inside water coherent domains, could allow for the implementation of a superfast network of interacting coherent domains able to represent a basic architecture for a novel kind of quantum hyper-computer based on the coherent dynamics of liquid water. This introduces a new frontier in the field of quantum computation, whose applications to both theoretical and advanced-technology fields (from the simulation of complex quantum systems to biotechnology, artificial intelligence, data encryption and decryption, etc.) would be very deep and nowadays unimaginable.


Journal ArticleDOI
TL;DR: In this article, the influence of thermal effects on superlocalization and on heating efficiency was studied theoretically, and it was shown that when time-dependent steady state motions of the magnetisation vector are present in the zero temperature limit, then deterministic and stochastic results are very similar to each other.

Journal ArticleDOI
01 Feb 2022-Icarus
TL;DR: In this article, the effects of tribocharging in this context are considered as grains in wind driven granular matter charge significantly, which leads to large electric fields above the granular bed.

Journal ArticleDOI
TL;DR: In this paper, a method of the excitation of perpendicular standing spin waves (PSSWs) of different orders in an optomagnonic microcavity by ultrashort laser pulses was proposed.


Journal ArticleDOI
TL;DR: In this article, the authors studied the dynamics of a magnetic bubble driven by a magnetic field gradient using micromagnetic simulations and showed that both the velocity and the skyrmion hall angle depend on the angle between the field gradient and the orientation of the bibubble.

Journal ArticleDOI
TL;DR: In this article, an unspecified scalar field potential is considered and treated not as an externally applied field but as a thermodynamic variable on an equal footing with the fluid variables, and it is shown that the second law of thermodynamics imposes a stringent constraint on the field, and the allowable field turns out to be only of gravity.
Abstract: Discovery of a novel thermodynamic aspect of nonrelativistic gravity is reported. Here, initially, an unspecified scalar field potential is considered and treated not as an externally applied field but as a thermodynamic variable on an equal footing with the fluid variables. It is shown that the second law of thermodynamics imposes a stringent constraint on the field, and, quite remarkably, the allowable field turns out to be only of gravity. The resulting field equation for the gravitational potential derived from the analysis of the entropy production rate contains a dissipative term due to irreversibility. It is found that the system relaxes to the conventional theory of Newtonian gravity up to a certain spatial scale, whereas on the larger scale there emerges non-Newtonian gravity described by a nonlinear field equation containing a single coefficient. A comment is made on an estimation of the coefficient that has its origin in the thermodynamic property of the system.


Journal ArticleDOI
TL;DR: In this paper, the authors provide a suitable theoretical foundation for the quantum coherent state which describes the electrostatic field due to a static external macroscopic charge distribution introduced by the author in 1998 and use it to re derive the formulae obtained in 1998 for the inner product of a pair of such states.
Abstract: We provide a suitable theoretical foundation for the notion of the quantum coherent state which describes the electrostatic field due to a static external macroscopic charge distribution introduced by the author in 1998 and use it to rederive the formulae obtained in 1998 for the inner product of a pair of such states. (We also correct an incorrect factor of $$4\pi$$ in some of those formulae.) Contrary to what one might expect, this inner product is usually non-zero whenever the total charges of the two charge distributions are equal, even if the charge distributions themselves are different. We actually display two different frameworks that lead to the same inner-product formulae, in the second of which Gauss’s law only holds in expectation value. We propose an experiment capable of ruling out the latter framework. We then address the problem of finding a product picture for QED—i.e. a reformulation in which it has a total Hamiltonian, arising as a sum of a free electromagnetic Hamiltonian, a free charged-matter Hamiltonian and an interaction term, acting on a Hilbert space which is a subspace (the physical subspace) of the full tensor product of a charged-matter Hilbert space and an electromagnetic-field Hilbert space. (The traditional Coulomb gauge formulation of QED isn’t a product picture in this sense because, in it, the longitudinal part of the electric field is a function of the charged matter operators.) Motivated by the first framework for our coherent-state construction, we find such a product picture and exhibit its equivalence with Coulomb gauge QED both for a charged Dirac field and also for a system of non-relativistic charged balls. For each of these systems, in all states in the physical subspace (including the vacuum in the case of the Dirac field) the charged matter is entangled with longitudinal photons and Gauss’s law holds as an operator equation; albeit the electric field operator (and therefore also the full Hamiltonian) while self-adjoint on the physical subspace, fails to be self-adjoint on the full tensor-product Hilbert space. The inner products of our electrostatic coherent states and the product picture for QED are relevant as analogues to quantities that play a role in the author’s matter-gravity entanglement hypothesis. Also, the product picture provides a temporal gauge quantization of QED which appears to be free from the difficulties which plagued previous approaches to temporal-gauge quantization.

Journal ArticleDOI
Lijun Wu1, Yan Han1, Shangfeng Chen1, Wu Li1, Longhai Shen1 
TL;DR: In this article, the geometric structural optimization and electronic properties of double-walled silicon nanotubes (DWSiNTs) were studied in terms of the self-consistent charge density functional tight binding (SCC-DFTB) method.

Journal ArticleDOI
TL;DR: In this paper, an intrinsic decoherence model is solved analytically for a Λ-type qutrit interacting with a coherent field through intensity-dependent coupling, and the effects of the qrit-cavity interaction, the intrinsic decoverherence and the initial coherent field intensity are examined on some quantum phenomena such as: atom population inversion, mixedness, entanglement as well as total correlation.
Abstract: In this paper, an intrinsic decoherence model is solved analytically for a Λ -type qutrit interacting with a coherent field through intensity-dependent coupling. The effects of the qutrit-cavity interaction, the intrinsic decoherence and the initial coherent field intensity are examined on some quantum phenomena as: atom population inversion, mixedness, entanglement as well as total correlation. It is found that the increase of the physical parameters, the regular oscillatory behavior of the qutrit-population collapses and revivals are changed remarkably. The interaction between the three-level atom and the coherent cavity field generates a strong mixture, negativity entanglement and total correlation (classical + quantum). The growth, the regularity and the stability of these quantum effects depend on the decoherence and the initial coherent cavity intensity.

Journal ArticleDOI
TL;DR: In this article, a new thermostat is introduced based on the single-atom sub-system, where its capability to control the temperature and produce the canonical ensemble is investigated.

Journal ArticleDOI
TL;DR: In this article, a novel electrophoretic molecular communication framework was proposed that utilizes a time-varying electric field, which induces time varying molecule velocities and in turn improves communication performance.


Journal ArticleDOI
TL;DR: Based on the modal superposition, the intensity and spin angular momentum (SAM) density are characterized by periodic changes from rotational symmetry to axial symmetry as the topological coefficient increases.

Journal ArticleDOI
TL;DR: In this paper, the transport properties, magnetization and dynamic magnetization relaxation rate measurements of (Li0.8Fe0.2)OHFeSe single crystals are presented at various magnetic fields and temperatures.

Journal ArticleDOI
TL;DR: In this article, the authors used the ferrolens for the observation and qualitative analysis of non-homogeneous magnetic fields and showed that they can display the projected magnetic field on air from a distance without needing to be in physical contact with the field source.


Journal ArticleDOI
TL;DR: In this paper, the authors present a methodology to impose micromechanical constraints, i.e. stress equilibrium at grain and sub-grain scale, to an arbitrary (non-equilibrated) voxelized stress field obtained, for example, by means of synchrotron X-ray diffraction techniques.