Journal articles: 'Distribution de charges non uniforme'

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Pshchelko, Nikolai, and Ekaterina Vodkailo. "Features of Electrostatic Fields and Their Force Action When Using Micro- and Nanosized Inter-Electrode Gaps." Materials 13, no. 24 (December 11, 2020): 5669. http://dx.doi.org/10.3390/ma13245669.

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The present work is devoted to assessing the influence of discreteness of electric charge distribution in the double electric layer on the characteristics of the electric fields and their force action in capacitor structures with small interelectrode gaps. Due to the fact that modern technologies often use submicron-sized interelectrode gaps, it is no longer possible to consider the electrodes uniformly charged because of the discreteness of the electric charge. The corresponding development of a mathematical and physical model for the study of a non-uniform electric field is suggested. Numerical calculations are carried out, expressions, criteria, and results that are convenient for practical evaluations are obtained. The physical and mathematical model for force characteristics of a non-uniform electric field is developed. With a sufficiently small size of the interelectrode gap, the integral force effect of discretely distributed charges can be significantly higher than with a uniform distribution of the same charge. At reasonable surface charge densities, these phenomena are usually observed at interelectrode gaps less than tenths of a micrometer.

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Yao, Jun, Eldin Wee Chuan Lim, Chi Hwa Wang, and Ning Li. "Process Tomographic Measurements of Granular Flow in a Pneumatic Conveying System." Advanced Materials Research 508 (April 2012): 75–79. http://dx.doi.org/10.4028/www.scientific.net/amr.508.75.

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The application of process tomography (PT) technologies, i.e. Electrostatic Tomography (EST) and Electrical Capacitance Tomography (ECT) to investigate complex industrial processes has obtained wide popularity in recent years. This study focuses on the characterization of non-uniformly distributed electrostatic effects across the cross-section of a pneumatic transportpipe. A digital electrometer was used to measure the electrostatics current and an ECT was used to observe the particle distribution in a vertical pipe. Due to non-uniform particle-wall collisions, the electrostatics generated was observed to be non-uniformly distributed across the pipe cross-section, especially at pipe bends and in a vertical pipe. Large electrostatic effects were associated with high particle concentration in the pipe. There was a good correspondence between the electrostatic effects measured and particle concentration distributions obtained using ECT. Based on ECT measurements at the vertical pipe section, it was observed that particles tended to concentrate at sections where generation of electrostatic charges was high. Thus, it is clear that electrostatic effects should be the key factor giving rise to non-uniform particle concentration distribution in pneumatic transport lines.

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Khan, Aminul Islam, and Prashanta Dutta. "Analytical Solution of Time-Periodic Electroosmotic Flow through Cylindrical Microchannel with Non-Uniform Surface Potential." Micromachines 10, no. 8 (July 26, 2019): 498. http://dx.doi.org/10.3390/mi10080498.

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Time-periodic electroosmotic flow (EOF) with heterogeneous surface charges on channel walls can potentially be used to mix species or reagent molecules in microfluidic devices. Although significant research efforts have been placed to understand different aspects of EOF, its role in the mixing process is still poorly understood, especially for non-homogeneous surface charge cases. In this work, dynamic aspects of EOF in a cylindrical capillary are analyzed for heterogeneous surface charges. Closed form analytical solutions for time-periodic EOF are obtained by solving the Navier–Stokes equation. An analytical expression of induced pressure is also obtained from the velocity field solution. The results show that several vortices can be formed inside the microchannel with sinusoidal surface charge distribution. These vortices change their pattern and direction as the electric field change its strength and direction with time. In addition, the structure and strength of the vorticity depend on the frequency of the external electric field and the size of the channel. As the electric field frequency or channel diameter increases, vortices are shifted towards the channel surface and the perturbed flow region becomes smaller, which is not desired for effective mixing. Moreover, the number of vorticities depends on the periodicity of the surface charge.

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Blokhintsev, L. D., and D. A. Savin. "Study of the Influence of Different Methods of Taking into Account the Coulomb Interaction on Determining Asymptotic Normalization Coefficients within the Framework of Exactly Solvable Model." Physics of Atomic Nuclei 84, no. 4 (July 2021): 401–7. http://dx.doi.org/10.1134/s1063778821040098.

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Abstract It is shown that the Schrödinger equation for the sum of the potential of a square well and the Coulomb potential of a uniformly charged sphere admits an analytical solution for arbitrary values of the orbital angular momentum. An explicit form of this solution has been found. Using the obtained solution, the influence of the Coulomb interaction for both point and distributed nuclear charges on the values of asymptotic normalization coefficients for various nuclear systems is investigated. It is shown that taking into account the non-point distribution of the nuclear charge has little effect on the calculated values of the asymptotic normalization coefficients, provided that the binding energy of the system is assumed to be fixed.

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Bakke, Knut, and Claudio Furtado. "Analysis of the interaction of an electron with radial electric fields in the presence of a disclination." International Journal of Geometric Methods in Modern Physics 16, no. 11 (November 2019): 1950172. http://dx.doi.org/10.1142/s021988781950172x.

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We consider an elastic medium with a disclination and investigate the topological effects on the interaction of a spinless electron with radial electric fields through the WKB (Wentzel, Kramers, Brillouin) approximation. We show how the centrifugal term of the radial equation must be modified due to the influence of the topological defect in order that the WKB approximation can be valid. Then, we search for bound states solutions from the interaction of a spinless electron with the electric field produced by this linear distribution of electric charges. In addition, we search for bound states solutions from the interaction of a spinless electron with radial electric field produced by uniform electric charge distribution inside a long non-conductor cylinder.

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Ye, Hui, and Austen Curcuru. "Deformation but not migration and rotation – a model study on vesicle biomechanics in a uniform DC electric field." Journal of Biomedical Engineering and Informatics 3, no. 1 (October 13, 2016): 18. http://dx.doi.org/10.5430/jbei.v3n1p18.

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Background: Biological cells migrate, deform and rotate in various types of electric fields, which have significant impact on the normal cellular physiology. To investigate electrically-induced deformation, researchers have used artificial giant vesicles that mimic the phospholipid bilayer cell membrane. Containing primarily the neutral molecule phosphatidylcholine, these vesicles deformed under evenly distributed, strong direct current (DC) electric fields. Interestingly, they did not migrate or rotate. A biophysical mechanism underlying the kinematic differences between the biological cells and the vesicles under electric stimulation has not been worked out. Methods: We modeled the vesicle as a leaky, dielectric sphere and computed the surface pressure, rotation torques and translation forces applied on the vesicle by a DC electric field. We compared these measurements with those in a biological cell that contains non-zero, intrinsic charges (carried by the functional groups on the membrane). Results: For both the vesicle and the cell, the electrically-induced charges interacted with the local electric field to generate radial pressure for deformation. However, due to the symmetrical distribution of both the charges and the electric field on the vesicle/cell surface, the electric field could not generate net translation force or rotational torques. For a biological cell, the intrinsic charges carried by the cell membrane could account for its migration and rotation in a DC electric field. Conclusions: Results from this work suggests an interesting control diagram of cellular kinematics and movements by the electric field: cell deformation and migration can be manipulated by directly targeting different charged groups on the membrane. Fate of the cell in an electric field depends not only on the delicately controlled field parameters, but also on the biological properties of the cell.

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Qie, X., S. Soula, and S. Chauzy. "Influence of ion attachment on the vertical distribution of the electric field and charge density below a thunderstorm." Annales Geophysicae 12, no. 12 (December 31, 1994): 1218–28. http://dx.doi.org/10.1007/s00585-994-1218-6.

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Abstract. A numerical model called PICASSO [Production d'Ions Corona Au Sol Sous Orage (French) and Production of Corona Ions at the Ground Beneath Thundercloud (English)], previously designed, is used to describe the evolution of the principal electrical parameters below a thunderstorm, taking into account the major part played by corona ions. In order to improve the model restitution of a real situation, various improvements are performed: an initial vertical distribution of aerosol particles is introduced instead of the previously used uniform concentration; time and space calculation steps are adjusted according to the electric field variation rate; the upper boundary condition is improved; and the coefficients of ion attachment are reconsidered with an exhaustive bibliographic study. The influence of the ion attachment on aerosol particles, on the electric field and charge density aloft, is studied by using three different initial aerosol particle concentrations at ground level and two types of initial vertical distributions: uniform and non-uniform. The comparison between field data and model results leads to adjust the initial aerosol particle concentration over the experimental site at the value of 5000 cm-3 which appears to be highly realistic. The evolutions of the electric field and of the charge density at altitude are greatly influenced by the aerosol concentration. On the contrary, the surface intrinsic field, defined as the electric field that would exist underneath a thundercloud if there were no local charges, is weakly affected when the model is forced by the surface field. A good correlation appears between the success in the triggered lightning attempts and this intrinsic field evaluation. Therefore, when only the surface field is available, the model can be used in a triggered lightning experiment.

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8

Oularé, Sékouba, Alexis Kassi Kouamé, Mahaman Bachir Saley, Gabriel Etienne Ake, Michel Amani Kouassi, Gnangui Christian Adon, Fernand Koffi Kouamé, and René Therrien. "Estimation de la conductivité hydraulique des zones discrètes de réseaux de fractures à partir des charges hydrauliques : application au bassin versant du N’zo (ouest de la Côte d’Ivoire)." Revue des sciences de l’eau 29, no. 3 (February 13, 2017): 279–301. http://dx.doi.org/10.7202/1038928ar.

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L’estimation de la conductivité hydraulique d’un aquifère de socle à l’échelle régionale demeure un défi majeur. À cette échelle, les données sont rares, en quantité et en qualité. Cette étude propose une approche d’estimation de la conductivité hydraulique des aquifères de socle à partir de la calibration d’un modèle d’écoulement au moyen des charges hydrauliques. Elle est appliquée au bassin du N’zo couvrant une superficie de 4 300 km2. La méthodologie adoptée fait l’hypothèse que la perméabilité de l’aquifère est liée à des fractures verticales, perméables sur 100 m à partir de la surface. Elle fait aussi l’hypothèse que ces fractures peuvent être identifiées sous forme de linéaments et que tous les linéaments sont des fractures et sont perméables. La première étape de cette méthodologie est la cartographie des zones discrètes de perméabilité de l’aquifère. Elles sont identifiées à partir de l’analyse de la densité et l’orientation des « fractures » à l’échelle de mailles de travail. Les fractures sont assimilées aux linéaments cartographiés à partir d’une image radar. Six configurations spatiales de zones discrètes de perméabilité sont générées avec des mailles carrées de 2 à 12 km de côté. La deuxième étape porte sur la construction du modèle numérique d’écoulement à partir des limites extérieures du bassin versant, du MNT (Modèle numérique de terrain), du réseau hydrographique et d’une recharge uniforme. Enfin, la troisième étape consiste à transférer chaque configuration de zones discrètes de perméabilité générée au sein du modèle numérique d’écoulement, puis à le calibrer en régime permanent au moyen de charges hydrauliques observées ponctuellement (86 points de mesure). Les résultats indiquent que le modèle optimal de distribution spatiale des zones discrètes de perméabilité est obtenu avec les mailles de 4 km de côté. Les conductivités hydrauliques calculées oscillent entre 1,1 x 10-6 et 2,4 x 10-5 m∙s-1. Cependant, ces valeurs doivent être prises avec précaution, car l’identification des zones homogènes du réseau de fractures est basée sur l’approche très controversée des linéaments et la calibration est effectuée seulement avec des charges hydrauliques et non avec des flux. Le modèle conceptuel ainsi élaboré pourrait être amélioré en caractérisant l’hétérogénéité de l’aquifère de socle à partir d’autres hypothèses telles que la lithologie et par l’introduction d’autres types de données dans la calibration (ex. : débits, carte piézométrique).

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9

Luts, A. R., A. P. Amosov, E. I. Latukhin, A. D. Rybakov, V. A. Novikov, and S. I. Shipilov. "Self-propagating high-temperature synthesis of (Al–2%Mn)–10%TiC and (Al–5%Cu–2%Mn)–10%TiC nanostructured composite alloys when doped with manganese powder." Izvestiya Vuzov. Poroshkovaya Metallurgiya i Funktsional’nye Pokrytiya (Universitiesʹ Proceedings. Powder Metallurgy аnd Functional Coatings), no. 3 (September 16, 2018): 30–40. http://dx.doi.org/10.17073/1997-308x-2018-3-30-40.

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The paper studies the effect of doping with manganese powder on the production of (Al–2%Mn)–10%TiC and (Al–5%Cu– 2%Mn)–10%TiC nanostructured composite alloys by self-propagating high-temperature synthesis (SHS) of TiC titanium carbide nanoparticles from Ti + C charge in the melt of matrix alloys. First, manganese metal powder was added to the matrix bases of Al and Al–5%Cu composite alloys in the amount of 2 wt%. This improved aluminum base tensile strength from 81 MPa (for the original A7 grade aluminum) to 136 MPa and aluminum-copper base tensile strength to 169 MPa. It was found that when aluminum was doped with manganese only, the SHS reaction proceeded weakly and not completely, and the carbide phase size in the resulting alloy (Al–2%Mn)–10%TiC varied from nanoscale to several micrometers. When 10% Na2TiF6halide salt was added to the SHS charge, the SHS process intensified, but the resulting alloy contained a considerable amount of pores, inclusions of unreacted charge and large agglomerates of TiC ceramic nanosized particles. Similar results were obtained in cases of using Ti + C and Ti + C + 10%Na2TiF6SHS charges, but with joint doping of matrix aluminum with copper and manganese, providing more uniform distribution of the TiC nanodispersed phase. The best results were obtained by reducing the Na2TiF6salt additive to 5 % of the SHS charge mass, which facilitated smoother and complete synthesis of predominantly TiC nanosized particles and the formation of a non-porous uniform microstructure of (Al–5%Cu–2%Mn)–10%TiC composite alloy with an ultimate tensile strength of 213 MPa and 6,6 % elongation.

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10

Ghosal, Sandip, and John D. Sherwood. "Screened Coulomb interactions with non-uniform surface charge." Proceedings of the Royal Society A: Mathematical, Physical and Engineering Sciences 473, no. 2199 (March 2017): 20160906. http://dx.doi.org/10.1098/rspa.2016.0906.

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The screened Coulomb interaction between a pair of infinite parallel planes with spatially varying surface charge is considered in the limit of small electrical potentials for arbitrary Debye lengths. A simple expression for the disjoining pressure is derived in terms of a two-dimensional integral in Fourier space. The integral is evaluated for periodic and random charge distributions and the disjoining pressure is expressed as a sum over Fourier–Bloch reciprocal lattice vectors or in terms of an integral involving the autocorrelation function, respectively. The force between planes with a finite area of uniform charge, a model for the DLVO interaction between finite surfaces, is also calculated. It is shown that the overspill of the charge cloud beyond the region immediately between the charged areas results in a reduction of the disjoining pressure, as reported by us recently in the long Debye length limit for planes of finite width.

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11

Liu, Bin, Ziqi Liu, Ning Luo, Luyao He, Jian Ren, and He Zhang. "Research on Features of Pipeline Crack Signal Based on Weak Magnetic Method." Sensors 20, no. 3 (February 2, 2020): 810. http://dx.doi.org/10.3390/s20030810.

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Quantitative online detection of microcracks in long-distance oil and gas pipelines is an international problem, and the effective detection method is still lacking. In this paper, a mathematical model of non-uniform distribution of crack magnetic charges is established based on the stress distribution laws of pipeline cracks under internal pressure. The weak magnetic signal characteristics of pipeline cracks with different sizes are analyzed. The internal pressure increasing factor of weak magnetic signals are extracted to analyze the corresponding relationship between crack size and weak magnetic signals. The experimental study of the X70 pipeline is carried out. The results show that the axial component of the weak magnetic signal at the crack has a maximum value near the tip, and a minimum value appears in the middle of the crack. The internal pressure increasing factor is introduced to quantify the weak magnetic signal, the crack is in a safe state (not expanding) when the internal pressure increasing factor is positive, the weak magnetic signal has a linear relationship with the crack size. However, the crack is in a dangerous state when the internal pressure increasing factor is negative, and the pipeline crack will expand as the internal pressure increases.

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12

Chen, Guang, and Siddhartha Das. "Electrostatics of soft charged interfaces with pH-dependent charge density: effect of consideration of appropriate hydrogen ion concentration distribution." RSC Advances 5, no. 6 (2015): 4493–501. http://dx.doi.org/10.1039/c4ra13946a.

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Explicit consideration of hydrogen ion concentration for describing the electrostatics of grafted polyelectrolyte layers with pH-dependent charge density exhibits the necessity of considering a non-uniform depth dependent monomer distribution.

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13

Sygut, Piotr. "Influence of Temperature Change on the Energy Parameters during Round Bars Rolling Process." Solid State Phenomena 220-221 (January 2015): 887–91. http://dx.doi.org/10.4028/www.scientific.net/ssp.220-221.887.

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The paper presents results of experimental studies on the effect of non-uniform temperature distribution over the metallic charge length on the energy parameters change during round bars rolling process. Experimental tests were conducted on the D370 Continuous Shape Mill in industrial works. From the tests carried out, it has been found that the main cause of occurrence of the non-uniform distribution of temperature over the charge length is the process of heating the metallic charge in the walking beam furnace. During rolling of bars from metallic charge with non-uniform temperature distribution over its length, changes in friction conditions in the zone of contact between the band and the rolls and in the plastic properties of steel being rolled occur. For decrease temperature during metallic charge rolling process about 100 °C (Fig. 2) in walking beam furnace, increase of rolling torque and total rolling power about 30% during rolling process metallic charge in first continuous shape mill stand was observed.

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Ewais, Emad, Ragab Mahani, Samy Mostafa, and Adel Ahmed. "Doping effect of SrZrO3 on KNLN ceramics structure and their dielectric properties." Journal of Advanced Dielectrics 08, no. 05 (October 2018): 1850033. http://dx.doi.org/10.1142/s2010135x18500339.

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In this work, lead-free systems; ([Formula: see text]) (K[Formula: see text]Na[Formula: see text]Li0.07) NbO3–[Formula: see text]SrZrO3 ([Formula: see text], 0.005, 0.050, 0.095 and 0.14) were synthesized by the conventional solid-state reaction technique. XRD, SEM, densification parameter as well as dielectric parameters of the obtained KNLN ceramics were investigated. XRD analysis showed the formation of orthorhombic perovskite structure in all investigated specimens. SrZrO3 (SZ) inhibited the grain growth and increased the distribution of grains uniformly in the microstructure. In addition, SZ changed the crystalline system of KNLN ceramics abnormally. As a consequence, the permittivity, dielectric loss as well as AC conductivity decreased remarkably. The ceramics of [Formula: see text] are characterized by low conductivity (10[Formula: see text][Formula: see text]S/cm), low dielectric loss (0.005) and relatively high permittivity (34). They can be useful for the electrical capacitors fabrication and filtering out noise from signals in resonant circuits. At frequencies lower than 105[Formula: see text]Hz, DC conductivity and separation of the charges at the interfaces were found to dominate the electrical behavior of ceramics, whereas at higher frequencies, a faster or dipole polarization may become more dominated. A broad peak has been observed in the imaginary part of electric modulus revealing to the non-Debye dielectric relaxation behavior. Quantum mechanical tunneling (QMT) was found to be the most suitable to characterize the electrical conduction mechanism in the ceramic compounds.

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15

MAKARYAN, A. H., H. S. HAROYAN, V. A. SAHAKYAN, and V. R. TADEVOSYAN. "INVESTIGATION OF NONLINEAR INTERACTION OF ELECTROMAGNETIC RADIATION WITH SPACE CHARGE IN VACUUM ELECTRONIC DEVICES." International Journal of Modern Physics: Conference Series 15 (January 2012): 105–12. http://dx.doi.org/10.1142/s2010194512007027.

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The nonlinear interaction of electromagnetic radiation in microwave, terahertz, and optical regions with non-uniformly distributed space charge in the interelectrode space of vacuum devices is investigated. The detection of electromagnetic radiation in the vacuum electronic tubes (diode and triode) with parallel plate electrodes is experimentally demonstrated. The dependence of the detected signal on the incident radiation power, direction of wave polarization, current characteristics and frequency of modulating signal has been investigated. The equation of motion of an electron in the field of electromagnetic wave in the presence of space charge was obtained, according to which, the detection is due to nonlinearity associated with the non-uniform distribution of electrons along the electrostatic field direction. The measured detection characteristics are in reasonable agreement with theoretical estimates.

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Macedo, Lucyano J. A., Filipe C. D. A. Lima, Rodrigo G. Amorim, Raul O. Freitas, Anur Yadav, Rodrigo M. Iost, Kannan Balasubramanian, and Frank N. Crespilho. "Interplay of non-uniform charge distribution on the electrochemical modification of graphene." Nanoscale 10, no. 31 (2018): 15048–57. http://dx.doi.org/10.1039/c8nr03893g.

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17

SUN, A. P., X. M. QIU, H. H. TONG, and Q. C. CHEN. "Ion transport in electrode sheath with non-uniform dusts." Journal of Plasma Physics 68, no. 4 (May 2002): 249–55. http://dx.doi.org/10.1017/s0022377802001976.

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The Monte Carlo method is used to simulate ion transport in an Ar plasma electrode sheath with a non-uniform dust. Charge exchange and elastic collisions between ions and neutral atoms and also the collection and Coulomb scattering of ions on the dust particles are examined during the motion of ions in the sheath. In order to study the effect of the non-uniform dust density and size on ion transport, we choose an exponent dust density distribution with a uniform dust size and a normal dust radius distribution with a uniform density and compare the simulation results with those for a uniform dust. It is found that both a non-uniform and a uniform dust density affect the ion density arriving at the electrode significantly and to the same degree. At the same time, it is also found that a non-uniform and uniform dust size influence the ion density arriving at the electrode greatly, but with a slight difference. Therefore, although the dust content is very low in most processing plasmas, its influence becomes evident whether its content is uniform or non-uniform in content and size. So, we can come to the conclusion that the key factors affecting the influence of dust particles on plasma behaviour are the linear density and the average radius of dust particles rather than their distribution.

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Tang, Dong, Zhixuan Ju, and Li Wang. "Simulation and Experimental Research on the Charged Characteristics of Particulate Matter in the Sensor under Different Exhaust States." Sensors 20, no. 21 (October 31, 2020): 6226. http://dx.doi.org/10.3390/s20216226.

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The particulate matter sensor needs to be used in order to detect the concentration of particulate matter in diesel engine exhaust, monitor the working condition of diesel particulate filter (DPF) in real time, and ensure the reliable operation of DPF. The flow field and electric field of the sensor are studied and their distribution in the sensor is analyzed. At the same time, the particle tracking model was used to simulate the charged characteristics of particles in the sensor under different exhaust states. It is found that the exhaust gas flow rate maintains stability after entering the outer protection zone and concentration test zone. The electric field is a non-uniform electric field and the direction of electric field intensity is from the high voltage electrode to the grounding electrode. The electric charge per particle will decrease with the increase of exhaust flow rate, but the electric charge shows a slow growth trend. The charge of particles increases with the increase of exhaust temperature, exhaust gas concentration and particle size. The study of the charged characteristics under different environmental conditions provides a theoretical basis for further improving the prototype mechanism of a leakage flow particle sensor.

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Li, Zhi Gang, Xiu Lan Huai, Da Wei Tang, Zhao Yin Wen, and Zhao Yi Dong. "Numerical Simulation of the Heat and Mass Transfer in a Sodium Sulfur Cell." Advanced Materials Research 347-353 (October 2011): 3956–62. http://dx.doi.org/10.4028/www.scientific.net/amr.347-353.3956.

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A mathematical model is built for the heat and mass transfer during charge and discharge in a sodium sulfur cell by coupling the electrochemical equations with the equations of species transport and heat transfer. Numerical simulation is performed for the two-dimensional axisymmetric domain of a single cell. The simulated charge-discharge characteristics agree well with the experimental data of a 650 Ah Na/S cell. The transient non-uniform distributions of the electric potential, the current density, the sodium polysulfide composition and the temperature during charge and discharge are obtained. The results show that the non-uniform distribution of the sodium polysulfide composition and current density may deteriorate the degradation of the ceramic electrolyte and the corrosion of the metal container, thus may shorten the cell life. The graphite fibers in the sulfur electrode matrix are preferably radially oriented, which is advantageous for reducing the cell resistance, for improving the rechargeability and for extending the cell life. The simulation results of the transient temperature fields provide useful guidance for the optimized thermal design so as to enhance the energy efficiency of the battery system.

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Guslienko, K. Yu. "Magnetic Vortex State Stability, Reversal and Dynamics in Restricted Geometries." Journal of Nanoscience and Nanotechnology 8, no. 6 (June 1, 2008): 2745–60. http://dx.doi.org/10.1166/jnn.2008.18305.

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Magnetic vortices are typically the ground states in geometrically confined ferromagnets with small magnetocrystalline anisotropy. In this article I review static and dynamic properties of the magnetic vortex state in small particles with nanoscale thickness and sub-micron and micron lateral sizes (magnetic dots). Magnetic dots made of soft magnetic material shaped as flat circular and elliptic cylinders are considered. Such mesoscopic dots undergo magnetization reversal through successive nucleation, displacement and annihilation of magnetic vortices. The reversal process depends on the stability of different possible zero-field magnetization configurations with respect to the dot geometrical parameters and application of an external magnetic field. The interdot magnetostatic interaction plays an important role in magnetization reversal for dot arrays with a small dot-to-dot distance, leading to decreases in the vortex nucleation and annihilation fields. Magnetic vortices reveal rich, non-trivial dynamical properties due to existance of the vortex core bearing topological charges. The vortex ground state magnetization distribution leads to a considerable modification of the nature of spin excitations in comparison to those in the uniformly magnetized state. A magnetic vortex confined in a magnetically soft ferromagnet with micron-sized lateral dimensions possesses a characteristic dynamic excitation known as a translational mode that corresponds to spiral-like precession of the vortex core around its equilibrium position. The translation motions of coupled vortices are considered. There are, above the vortex translation mode eigenfrequencies, several dynamic magnetization eigenmodes localized outside the vortex core whose frequencies are determined principally by dynamic demagnetizing fields appearing due to restricted dot geometry. The vortex excitation modes are classified as translation modes and radially or azimuthally symmetric spin waves over the vortex ground state. Studying the spin eigenmodes in such systems provides valuable information to relate the particle dynamical response to geometrical parameters. Unresolved problems are identified to attract attention of researchers working in the area of nanomagnetism.

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Li, Hanqing, Bonan Xu, Hanhui Jin, Haiou Wang, and Jianren Fan. "Two improved electronegativity equalization methods for charge distribution in large scale non-uniform system." Computers & Mathematics with Applications 81 (January 2021): 693–701. http://dx.doi.org/10.1016/j.camwa.2019.12.017.

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Mirbozorgi, S. A., H. Niazmand, and M. Renksizbulut. "Electro-Osmotic Flow in Reservoir-Connected Flat Microchannels With Non-Uniform Zeta Potential." Journal of Fluids Engineering 128, no. 6 (March 24, 2006): 1133–43. http://dx.doi.org/10.1115/1.2353261.

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The effects of non-uniform zeta potentials on electro-osmotic flows in flat microchannels have been investigated with particular attention to reservoir effects. The governing equations, which consist of a Laplace equation for the distribution of external electric potential, a Poisson equation for the distribution of electric double layer potential, the Nernst-Planck equation for the distribution of charge density, and modified Navier-Stokes equations for the flow field are solved numerically for an incompressible steady flow of a Newtonian fluid using the finite-volume method. For the validation of the numerical scheme, the key features of an ideal electro-osmotic flow with uniform zeta potential have been compared with analytical solutions for the ionic concentration, electric potential, pressure, and velocity fields. When reservoirs are included in the analysis, an adverse pressure gradient is induced in the channel due to entrance and exit effects even when the reservoirs are at the same pressure. Non-uniform zeta potentials lead to complex flow fields, which are examined in detail.

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23

Elshenawy, T. "A MODIFIED VIRTUAL ORIGIN MODEL FOR SHAPED CHARGE JET PENETRATION WITH NON-UNIFORM DENSITY DISTRIBUTION." International Conference on Applied Mechanics and Mechanical Engineering 16, no. 16 (May 1, 2014): 1–21. http://dx.doi.org/10.21608/amme.2014.35477.

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Elshenawy, Tamer, Ahmed Elbeih, and Qing Li. "A Modified Penetration Model for Copper-Tungsten Shaped Charge Jet with Non-Uniform Density Distribution." Central European Journal of Energetic Materials 13, no. 4 (December 20, 2016): 927–43. http://dx.doi.org/10.22211/cejem/65141.

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Wahab, M. H. A., N. A. M. Jamail, E. Sulaiman, Q. E. Kamarudin, N. A. Othman, and S. M. N. S. Othman. "Space Charge and Electric Field Analysis on Contaminated XLPE Insulator." Indonesian Journal of Electrical Engineering and Computer Science 12, no. 1 (October 1, 2018): 370. http://dx.doi.org/10.11591/ijeecs.v12.i1.pp370-377.

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<p>Nowadays, XLPE cable has been widely used because it has better resistance than other cables. XLPE insulation has unique features including a high dielectric strength and high insulation resistance. A lot of researches based on hardware and software have been conducted to prove the effectiveness of XLPE cable such as AC and DC applications and Space Charge Distribution measurement under HVDC at High Temperature. This research focused on analysis of space charge and electric field on XLPE cable with effect of non-uniform contamination layer by using Quickfield Software. Non-uniform contaminations have been applied along XLPE cable using Arsenic Tribromide (AsBr3), Boron Bromide (BBr3), Ethylene Dichloride (CH2C1), Formic Acid (CH1O2), Formamide (CH3NO) and Alcohol element. Presence of these contamination elements represent of underground contamination. The size and layer of the contamination were non-uniform type. From the results, it is shown that lower dielectric constant of contamination will affect more on charge of XLPE insulation. As a conclusion, it can be seen lower dielectric constant value of contamination element greatly affecting the performance of XLPE insulation. Furthermore, size of contamination also influences the content of charge in contamination where the bigger the contamination size, the more charge contained in the contamination.</p>

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Klein, Matthew Paul, and Jae Wan Park. "Effects of Non-Uniform Temperature on In-Situ Current Distribution and Non-Uniform State of Charge Measurements for LiFePO 4 and LiNiMnCoO 2 Cells." ECS Transactions 77, no. 11 (July 7, 2017): 81–97. http://dx.doi.org/10.1149/07711.0081ecst.

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Zhang, Daning, Guanwei Long, Yang Li, Haibao Mu, and Guanjun Zhang. "Effect of Radial Moisture Distribution on Frequency Domain Dielectric Response of Oil-Polymer Insulation Bushing." Polymers 12, no. 6 (May 27, 2020): 1219. http://dx.doi.org/10.3390/polym12061219.

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In order to realize the diagnosis of water distribution, this paper analyzes the interface polarization and macroscopic space charge polarization mechanism when the water distribution is non-uniform. The experimental results of this paper and bushing show that when the moisture distribution is non-uniform, there is a significant loss peak in the tanδ-f curve. The loss peak shifts to higher frequencies as the non-uniformity coefficient increases. There are common intersection points between multiple tanδ-f curves. Further, this paper realizes the diagnosis of the location of moisture distribution through Frequency Domain Spectroscopy (FDS) testing of different voltages and different wiring methods based on the macroscopic space charge polarization. In the single-cycle FDS test, when the positive electrode is first added to the area with higher moisture content, the amplitude of the tanδ-f curve is smaller. The tanδ-f curves under different wiring methods constitute a “ring-shaped” loss peak. As the voltage increases, the peak value of the loss peak shifts to the lower frequency band. As the temperature increases, the peak value of the loss peak shifts to higher frequencies. Based on the above rules and mechanism analysis, this research provides a new solution for the evaluation of moisture content of oil-immersed polymers equipment.

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Nespolo, Massimo, and Benoît Guillot. "CHARDI2015: charge distribution analysis of non-molecular structures." Journal of Applied Crystallography 49, no. 1 (February 1, 2016): 317–21. http://dx.doi.org/10.1107/s1600576715024814.

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The charge distribution method describes non-molecular crystal structures in a Madelung-type approach in which the formal oxidation number (`charge') of each atom is distributed among its neighbours. The sum of the distributed charges gives back the input charge when a structure is correctly refined and well balanced, so that the method can be used for structure validation and for the analysis of over- and underbonding effects. A new version of the software used to compute the charge distribution is presented, now with a CIF parser and graphical user interface.

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Li, Z., S. C. Mantell, and J. H. Davidson. "Mechanical analysis of streamlined tubes with non-uniform wall thickness for heat exchangers." Journal of Strain Analysis for Engineering Design 40, no. 3 (April 1, 2005): 275–85. http://dx.doi.org/10.1243/030932405x12858.

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An approach to select the tube wall thickness distribution of streamlined tubes intended for use in heat exchangers is developed. The goal is to retain a streamlined outer profile (resist deformation) and to prevent strain failure due to the applied internal pressure. The effect of the tube wall thickness distribution on heat transfer is also considered. The strain is calculated as a function of several dimensionless geometric ratios and the ratio of the internal pressure to material modulus. Using the finite element method, a set of dimensionless design curves is created for elliptical tube geometries. From these curves, a range of possible materials and tube geometries can be selected that meet a specific strain limit. To illustrate the approach, structure-satisfied elliptical designs are selected and their thermal performance is evaluated for an automotive radiator and an automotive charge air cooler made of polymeric materials. The same method can be extended to tubes of other shapes and materials.

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Danger, Grégoire, Robert Pascal, and Hervé Cottet. "Non-uniform surface charge distributions in CE: Theoretical and experimental approach based on Taylor dispersion." ELECTROPHORESIS 29, no. 20 (November 2008): 4226–37. http://dx.doi.org/10.1002/elps.200800128.

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KHAIR, ADITYA S., and TODD M. SQUIRES. "Surprising consequences of ion conservation in electro-osmosis over a surface charge discontinuity." Journal of Fluid Mechanics 615 (November 25, 2008): 323–34. http://dx.doi.org/10.1017/s002211200800390x.

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A variety of microfluidic technologies utilise electrokinetic transport over rigid surfaces possessing rapid variations in charge. Here, as a paradigmatic model system for such situations, we consider electro-osmosis past a flat plate possessing a discontinuous jump in surface charge. Although the problem is relatively simple to pose, our analysis highlights a number of interesting and somewhat surprising features. Notably, the standard assumption that the electric field outside the diffuse screening layer is equal to the uniform applied field leads to a violation of ion conservation, since the applied field drives an ionic surface current along the diffuse layer downstream of the jump, whereas there is zero surface current upstream. Instead, at the surface charge discontinuity, field lines are drawn into the diffuse layer to supply ions from the bulk electrolyte, thereby ensuring ion conservation. A simple charge conservation argument reveals that the length-scale over which this process occurs is of the order of the ratio of surface-to-bulk electrolyte conductivities, LH=σs/σb. For a highly charged surface, LH can be several orders of magnitude greater than the Debye screening length λD, which is typically nanometres in size. Remarkably, therefore, nano-scale surface conduction may cause micrometre-scale gradients in the bulk electric field. After a distance O(LH) downstream, the bulk field ‘heals’ and is once again equal to the applied field. Scaling all distances with the ‘healing length’ LH yields a universal set of equations for the bulk field and fluid flow, which are solved numerically. Finally, we discuss the role of surface conduction in driving a non-uniform ion distribution, or concentration polarization, in the bulk electrolyte.

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Pham, Hai Duong, Wu-Pei Su, Thi Dieu Hien Nguyen, Ngoc Thanh Thuy Tran, and Ming-Fa Lin. "Rich p -type-doping phenomena in boron-substituted silicene systems." Royal Society Open Science 7, no. 12 (December 2020): 200723. http://dx.doi.org/10.1098/rsos.200723.

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The essential properties of monolayer silicene greatly enriched by boron substitutions are thoroughly explored through first-principles calculations. Delicate analyses are conducted on the highly non-uniform Moire superlattices, atom-dominated band structures, charge density distributions and atom- and orbital-decomposed van Hove singularities. The hybridized 2 p z –3 p z and [2s, 2 p x , 2 p y ]–[3s, 3 p x , 3 p y ] bondings, with orthogonal relations, are obtained from the developed theoretical framework. The red-shifted Fermi level and the modified Dirac cones/ π bands/ σ bands are clearly identified under various concentrations and configurations of boron-guest atoms. Our results demonstrate that the charge transfer leads to the non-uniform chemical environment that creates diverse electronic properties.

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Benda, Vitezslav, and Zdenek Novak. "OCVD carrier lifetime measurements on an inhomogeneous diode structure." Facta universitatis - series: Electronics and Energetics 15, no. 1 (2002): 33–39. http://dx.doi.org/10.2298/fuee0201033b.

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This paper investigates the problem of evaluating the lifetime of a carrier measured by the OCVD method on structures with a non-uniform carrier lifetime distribution. A simple model of two diodes connected in parallel (lumped charge approximation) has been used for evaluating the measured carrier lifetime. The theoretical analysis was experimentally verified.

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Herro, Z. G., Matthias Bickermann, Boris M. Epelbaum, Roland Weingärtner, Ulrike Künecke, and Albrecht Winnacker. "Uniform Axial Charge Carrier Concentration in PVT-Grown p-Type 6H SiC by Non-Uniform Distribution of Boron in the Powder Source." Materials Science Forum 457-460 (June 2004): 719–22. http://dx.doi.org/10.4028/www.scientific.net/msf.457-460.719.

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Fujii, Masayuki, Masanori Yamada, Masumi Fukuma, Yoshinobu Murakami, and Masayuki Nagao. "Relationship between Deterioration of Epoxy Resin and Change of Space Charge Distribution under Non-uniform Electric Field." IEEJ Transactions on Fundamentals and Materials 137, no. 11 (2017): 608–13. http://dx.doi.org/10.1541/ieejfms.137.608.

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Sygut, Piotr, Konrad Laber, and Stanisław Borkowski. "Investigation of the non-uniform temperature distribution on the metallic charge length during round bars rolling process." Manufacturing Technology 12, no. 2 (December 1, 2012): 260–63. http://dx.doi.org/10.21062/ujep/x.2012/a/1213-2489/mt/12/2/260.

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Deng, Jiang Hua, Yi Ming Zheng, Chao Tang, and Yan Ran Zhan. "Analysis of Charge Circuit and Discharge Circuit in Electromagnetic Riveting." Applied Mechanics and Materials 241-244 (December 2012): 606–9. http://dx.doi.org/10.4028/www.scientific.net/amm.241-244.606.

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The analysis of charge circuit and discharge circuit is a key part in the theoretical study of electromagnetic riveting electromagnetic field. Numerical simulation was used to establish the charge circuit model and the discharge circuit model which was an electric circuit-magnetic circuit coupling process by ANSYS. The simulation of charge circuit shows that the development of the charge current over time is an exponential descending change and that of the charge voltage over time is an exponential ascending change. And, the simulation of discharge circuit indicates that the driver is mainly subjected to axial magnetic force, whose distribution is non-uniform along the radial direction of driver, and the maximum value of axial magnetic force locates in about half of the driver radius.

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Matveyev, Yury, Vitalii Mikheev, Dmitry Negrov, Sergei Zarubin, Abinash Kumar, Everett D. Grimley, James M. LeBeau, Andrei Gloskovskii, Evgeny Y. Tsymbal, and Andrei Zenkevich. "Polarization-dependent electric potential distribution across nanoscale ferroelectric Hf0.5Zr0.5O2 in functional memory capacitors." Nanoscale 11, no. 42 (2019): 19814–22. http://dx.doi.org/10.1039/c9nr05904k.

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Using standing-waves in HAXPES technique, we reveal non-linear electrostatic potential profile across nanoscale ferroelectric (FE) HfZrO₄ layer in memory capacitors for both polarization directions, implying the drift of non-FE charges at interfaces.

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39

Ba̧k, G. W., and A. Lipiński. "Space charge-limited currents in thin film solid dielectrics with non-uniform deep-trap distributions: numerical solutions." Thin Solid Films 238, no. 2 (February 1994): 290–94. http://dx.doi.org/10.1016/0040-6090(94)90069-8.

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40

Kikunaga, Kazuya. "System for Visualizing Surface Potential Distribution to Eliminate Electrostatic Charge." Sensors 21, no. 13 (June 27, 2021): 4397. http://dx.doi.org/10.3390/s21134397.

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A mixture of positive and negative static charges exists in the same plane on an insulator surface, and this can cause production quality problems at manufacturing sites. This study developed a system with a vibration array sensor to rapidly measure the surface potential distribution of an object in a non-contact and non-destructive manner and with a high spatial resolution of 1 mm. The measurement accuracy differed greatly depending on the scanning speed of the array sensor, and an optimum scanning speed of 10 mm/s enabled rapid measurements (within <3 s) of the surface potential distribution of a charged insulator (area of 30 mm × 30 mm) with an accuracy of 15%. The relationship between charge and dust on the surface was clarified to easily visualize the uneven static charges present on it and thereby eliminate static electricity.

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41

Autran, J. L., D. Munteanu, R. Dinescu, and M. Houssa. "Stretch-out of high-permittivity MOS capacitance–voltage curves resulting from a lateral non-uniform oxide charge distribution." Journal of Non-Crystalline Solids 322, no. 1-3 (July 2003): 219–24. http://dx.doi.org/10.1016/s0022-3093(03)00205-9.

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42

Sebastian, Mróz. "Influence of Non-Uniform Temperature Distribution on Metallic Charge Length on Energy and Force Parameters During Groove-Rolling." Journal of Iron and Steel Research International 19, no. 8 (August 2012): 17–24. http://dx.doi.org/10.1016/s1006-706x(12)60134-4.

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Ivchenko, Vladimir Valerievich. "What is the most ``non-point'' gravitating or electrically charged object?" Revista Mexicana de Física E 17, no. 1 Jan-Jun (January 28, 2020): 69. http://dx.doi.org/10.31349/revmexfise.17.69.

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In this paper we search the shape of an aspherical body and the direction in space, for which the greatest deviations from the point mass field (the difference from the inverse-square law) take place for large distances from the field source. It turns out to be a system of two equal point-like masses at the poles of a fixed sphere (giving the greatest positive deviations from the point mass field) and uniform distribution of point-like masses (discrete or continuous) around the sphere equator (giving the greatest negative deviations from the point mass field). In these cases the extremal direction of the field measurement respectively passes through point-like particles and coincides with the axis of symmetry of a ring, which is perpendicular to its plane. Our numerical estimations show that any body can be considered with reasonable accuracy (the relative error in the determination of the field strength is less than $5 \%$) as point-like mass if the distance to the observation point is more than an order of magnitude larger than its characteristic sizes. The problem considered in this paper can help readers to probe the limits of applicability of the field point source model.

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44

Yakovenko, Vladimir M., and I. V. Yakovenko. "Surface Plasmon Instability Produced by a Charge-Particle Beam Passing through a Medium with a Non-Uniform Potential Distribution." Telecommunications and Radio Engineering 55, no. 10-11 (2001): 6. http://dx.doi.org/10.1615/telecomradeng.v55.i10-11.180.

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Zhou, Qun, Cai Liang, Jiawei Hu, Xiaoping Chen, and Jiliang Ma. "Numerical simulation of electric field in cylindrical silo based on non-uniform electrostatic charge distribution caused by particle segregation." Powder Technology 383 (May 2021): 336–47. http://dx.doi.org/10.1016/j.powtec.2021.01.054.

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Fraser, R. D. B., and B. L. Trus. "Molecular mobility in the gap regions of type 1 collagen fibrils." Bioscience Reports 6, no. 2 (February 1, 1986): 221–26. http://dx.doi.org/10.1007/bf01115010.

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Recent studies of the structure of Type I collagen fibrils (Piez and Trus, Biosci. Rep.1:801–810, 1981; Fraser, MacRae, Miller and Suzuki, J. Mol. Biol.167:497–521, 1983) suggest that the segments of the collagen molecule which comprise the gap region are more mobile than those which comprise the overlap region. We have analyzed the distribution of amino acid residues and triplet types between the two regions, and find significantly non-uniform distributions for Ala, Gln, His, Hyp, Leu, Phe, and Tyr, and for triplets containing two imino acid residues. Taken together with the lower packing density in the gap region these observations provide a basis for understanding the greater mobility of the molecular segments in the gap region. In addition, we have examined the linear distribution of residue types in the two regions and also the hydropathy profile (Kyte and Doolittle, J. Mol. Biol.157: 105–113, 1982). These reveal a segment of the gap region comprising helical residues 165–173, 399–407, 633–641 and 867–975 which has the highest hydropathy index, is devoid of charged residues, and contains very high proportions of Ala, Hyp and Phe.

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Wang, An Ling, and Fu Ping Liu. "Application Boundary Element Method to Compute the Potential of the Eight-Needle Electrodes." Advanced Materials Research 605-607 (December 2012): 147–51. http://dx.doi.org/10.4028/www.scientific.net/amr.605-607.147.

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According to the electric potential on the eight -needle electrodes in vacuum, the discrete equations based on the indeterminate linear charge density (LCD) are established by the boundary element integral equations. The non-uniform distributions of LCD on the needle electrodes are calculated through solving a set of linear equations. With the help of the LCD, the potential generated by the multi-needle electrodes at any point in vacuum have been obtained. In this paper we have realized the numerical calculation of the static field distributions for multi-needle electrode system by the boundary element approach.

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Liu, Fu Ping, and An Ling Wang. "Boundary Element Numerical Method for Electric Potential Generated by Eleven-Needle Electrodes in Vacuum." Applied Mechanics and Materials 415 (September 2013): 647–50. http://dx.doi.org/10.4028/www.scientific.net/amm.415.647.

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Abstract. According to the electric potential on the eleven -needle electrodes in vacuum, the discrete equations based on the indeterminate linear charge density (LCD) are established by the boundary element integral equations. The non-uniform distributions of LCD on the needle electrodes are calculated through solving a set of linear equations. With the help of the LCD, the potential generated by the multi-needle electrodes at any point in vacuum have been obtained. In this paper we have realized the numerical calculation of the static field distributions for multi-needle electrode system by the boundary element approach.

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Stenehjem, David D., Arati Dahal, Brandon Kyle Bellows, and Diana I. Brixner. "An empirical assessment of breast cancer treatment charges by survival status." Journal of Clinical Oncology 31, no. 15_suppl (May 20, 2013): e11541-e11541. http://dx.doi.org/10.1200/jco.2013.31.15_suppl.e11541.

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e11541 Background: Breast cancer treatment can be costly, but it remains unknown if charges differ between patients who die during treatment compared to survivors. The objective of this study was to assess annualized mean charges by survival status in patients with a diagnosis of breast cancer. Methods: The University of Utah Enterprise Data Warehouse was used to analyze patients ≥18 years with a diagnosis of breast cancer identified by ICD-9 code (initial diagnosis defined as index date) treated at the Huntsman Cancer institute (HCI) from 2002-2010. The HCI Tumor Registry was used to determine stage at diagnosis and other cancers. Cause and date of death was captured from the Utah Population Database. Cancer-related (CR) and non-CR charges were by ICD-9 codes from index date until death or end of the follow-up period, were weighted by the inverse probability of survival, and annualized. Generalized linear models (GLM) with gamma distribution and log link function were used to examine charges by survival status, while adjusting for baseline characteristics including demographics, stage, and comorbidities. Results: There were 1783 patients included, of which 296 (17%) died. Compared to survivors, deceased patients were older (mean age 62 vs. 56), more were diagnosed with stage IV disease (17% vs. 3%), and fewer with stage I (24% vs. 45%); all p<0.001. Mean unadjusted annualized CR charges were not different between groups (deceased $34,310 vs. alive $32,797; p=0.64), but non-CR charges were higher for deceased patients ($39,926 vs. $16,538; p<0.001). GLM results indicated deceased patients had 90% higher annualized CR charges relative to survivors (p<0.001) and higher charges for stages I, II, and III (125%, 86%, and 69%, respectively; all p<0.001). Deceased patients had 124% higher annualized non-CR charges relative to survivors (p<0.001) and higher charges for stages I, II, and III (174%, 146%, and 107%, respectively; all p<0.001). Charges did not differ between groups for stage IV patients. Conclusions: When adjusting for confounders, death was associated with higher CR and non-CR charges, except in patients with stage IV disease at diagnosis. Patients who died during treatment may have had more aggressive disease leading to higher charges.

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Kim, Ki Hyun, Joong Jung Kim, Wei Xing Xia, Zentaro Akase, and Daisuke Shindo. "Electron Holography on Charging Effect in Non-Conductive Materials." Materials Science Forum 561-565 (October 2007): 2075–78. http://dx.doi.org/10.4028/www.scientific.net/msf.561-565.2075.

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The charging effects on non-conductive materials due to electrons irradiation were investigated by electron holography. The phenomena that the charging effects were more enhanced with an increase in the incident electron density were visualized through the direct observations in the electric potential distribution around the specimens. In addition, through the comparison between the electron holography results and the simulations, we were able to obtain the quantitative results indicating the amount of charges accumulated during electron irradiation.

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Journal articles on the topic 'Distribution de charges non uniforme'

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