Dynamic Electric Field Research Articles

Dynamic Electric Field Alignment Determines the Water Rotational Motion around Protein.

Water rotational dynamics in biomolecular solution is crucial to evaluating and controlling biomolecule stability. In this molecular dynamics simulation (MD) study on lysozyme solutions, we present how the exerted internal electric field determines water rotational dynamics. We find that the relaxation time of water rotation is equivalent to that of the reorientation of the exerted overall electric field for every single water molecule, regardless of its translation mode. Namely, water molecular rotation synchronizes with the exerted field reorientation. We also map the reorientation process of the electric field at fixed points relative to protein in the solution, which displays the local hydration dynamics commensurate with the reported time-dependent fluorescence Stokes shift (TDFSS) measurements. Comparing the spatial distribution of local field reorientation relaxation time with that of rotational relaxation time, we further suggest that water rotation dynamics are subject to the reorientation of the local overall field within the hydration layer. While outside the hydration layer, the relaxation time of the local electric field reorientation is short enough (subpicosecond) to assume the δ function, showing the electric force with randomly changing orientation is applied to each water molecule.

CuO/NaNbO3 nanorod piezoelectric photocatalysts promoted tetracycline removal: a dynamic internal electric field

The piezoelectric electric field inside CuO/NaNbO3 nanorods promoted the separation of photoinduced carriers and inhibited being saturated by free carriers.

The dynamic behavior of a piezoelectric strip with a salient and an inclusion under guided SH waves

Dynamic stress around the inclusion and salient in a piezoelectric strip subjected to dynamic incident anti-plane shearing (guided SH wave) is calculated. Using the repeated image superposition method, the analytical expression for scattering wave, satisfying stress-free and electric insulation conditions at the upper and lower horizontal boundaries of the strip, is obtained. The integral equations are set up with the boundary conditions and solved by orthogonal function expansion and effective truncation techniques. The obtained results clarify the characteristic features of the influence on the dynamic stress concentration factor and electric field intensity concentration factor. The analytical solutions are compared to the finite element modeling results to verify the accuracy of the conclusions of this paper.

Boosting piezo/photo-induced charge transfer of a bi-piezoelectrics BaTiO3/CdS isotype junction for kinetic optimization

The photocatalytic activity of BaTiO3 is largely constrained by its inherent wide bandgap sensitivity only to Ultraviolet (UV) light and the limited effect of severe carrier recombination during the drift, diffusion, and surface transfer. In response, researchers have reported a bi-piezoelectrics isotype junction between BaTiO3/CdS that is adjusted via a synergistic piezo-photocatalytic effect. As a result of the CdS coating, the composite can effectively increase the absorption range from UV to visible light. By contrast, the composite can prevent malicious charge recombination due to a large band offset caused by piezoelectric effects. Meanwhile, the piezo-potential induced by periodic ultrasonic waves can generate a dynamic built-in electric field resulting from unscreened polar charges, which has been demonstrated as an alternating driving force for further suppressing the charge recombination. Hence, compared to pure BaTiO3 and CdS, the BaTiO3/CdS composite displayed a significantly higher piezo-photocatalytic degradation activity, by an amount equal to 18% and 16.9%, respectively, during 70 min. This work facilitates our insight into a bi-piezoelectrics isotype junction and suggests new strategies to enhance the effectiveness of piezoelectric nanocrystals for water purification.

Flexible anodic bonding for the bonding between elastomer and metal

AbstractConsidering the inadaptability of traditional anodic bonding to polymer materials, the flexible anodic bonding process is developed. The bonding characteristics of the dynamic intelligent electric fields with the low‐temperature plasma surface treatment to polymer and ultrasonic‐assisted preconnection before bonding are very suitable for the anodic bonding of polymer elastomer to aluminum (Al) sheet. A series of composite polyurethane elastomer cathode materials (CPECs) with good bonding properties are prepared and characterized. The highest ionic conductivity of CPECs can reach to 2.7 × 10−3 S/cm (CPEC2) at 75°C. After bonded, it is determined that a uniform and dense intermediate bonding layer showed by SEM is formed between CPECs and Al. In addition, different elements including C, O, F, S, and Al are clearly identified by EDS in the bonding layers, showing that the process of flexible anodic bonding has accompanied the directional migration of ions. The maximum tensile strength of bonding layer for CPEC2 and Al (CPEC2‐Al) is up to 2.03 MPa. It is proven that the developed flexible anodic bonding can effectively improve the joint quality and reliability for polymer elastomer materials. All these results of anodic bonding are more potentially valuable to the packaging of flexible devices.

Boosting the performance of single-atom catalysts via external electric field polarization

Single-atom catalysts represent a unique catalytic system with high atomic utilization and tunable reaction pathway. Despite current successes in their optimization and tailoring through structural and synthetic innovations, there is a lack of dynamic modulation approach for the single-atom catalysis. Inspired by the electrostatic interaction within specific natural enzymes, here we show the performance of model single-atom catalysts anchored on two-dimensional atomic crystals can be systematically and efficiently tuned by oriented external electric fields. Superior electrocatalytic performance have been achieved in single-atom catalysts under electrostatic modulations. Theoretical investigations suggest a universal “onsite electrostatic polarization” mechanism, in which electrostatic fields significantly polarize charge distributions at the single-atom sites and alter the kinetics of the rate determining steps, leading to boosted reaction performances. Such field-induced on-site polarization offers a unique strategy for simulating the catalytic processes in natural enzyme systems with quantitative, precise and dynamic external electric fields.

Numerical Analysis for a P-Drift Region N-IGBT With Enhanced Dynamic Electric Field Modulation Effect

This article studies the underlying physical mechanism and comprehensive characteristics of the N-channel IGBT (N-IGBT) with P-drift region (PD-IGBT). Distinguishing from the conventional N-IGBT with N-drift region (ND-IGBT), the main blocking junction ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${J}_{\text {MB}}$ </tex-math></inline-formula> ) of the PD-IGBT is changed from the emitter side to the collector side, which leads to a significant enhancement effect of dynamic electric field modulation. Based on the effect, the PD-IGBT features fast dynamic electric field (E-field) building speed in the drift region and a high E-field at the edge of the field-stop (FS) layer, which can extract excess carriers stored in the device rapidly during the turn-off transient, thus reducing the turn-off loss ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${E}_{\rm {OFF}}$ </tex-math></inline-formula> ) and turn-off time ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${t}_{\rm {OFF}}$ </tex-math></inline-formula> ) of the device. Moreover, the change of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${J}_{\text {MB}}$ </tex-math></inline-formula> location can also alleviate the E-field crowding phenomenon at the trench gate corner, thus providing an optimized relationship between breakdown voltage (BV) and ON-state voltage, as well as high avalanche energy. Simulation results show that, when compared with the state-of-the-art N-channel ND-IGBT, the PD-IGBT offers 46% shorter <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${t}_{\rm {OFF}}$ </tex-math></inline-formula> , 57% lower <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${E}_{\rm {OFF}}$ </tex-math></inline-formula> , and 60% larger avalanche energy without compromising other device characteristics.

Dynamically actuated soft heliconical architecture via frequency of electric fields

Dynamic electric field frequency actuated helical and spiral structures enable a plethora of attributes for advanced photonics and engineering in the contemporary era. Nevertheless, leveraging the frequency responsiveness of adaptive devices and systems within a broad dynamic range and maintaining restrained high-frequency induced heating remain challenging. Herein, we establish a frequency-actuated heliconical soft architecture that is quite distinct from that of common frequency-responsive soft materials. We achieve reversible modulation of the photonic bandgap in a wide spectral range by delicately coupling the frequency-dependent thermal effect, field-induced dielectric torque and elastic equilibrium. Furthermore, an information encoder prototype without the aid of complicated algorithm design is established to analogize an information encoding and decoding process with a more convenient and less costly way. A technique for taming and tailoring the distribution of the pitch length is exploited and embodied in a prototype of a spatially controlled soft photonic cavity and laser emission. This work demonstrates a distinct frequency responsiveness in a heliconical soft system, which may not merely inspire the interest in field-assisted bottom-up molecular engineering of soft matter but also facilitate the practicality of adaptive photonics.

Applicability of semiclassical methods for modeling laser-enhanced fusion rates in a realistic setting

In the context of the potential laser-induced enhancement to the rates of ${\mathrm{DHe}}^{3}$ and DT fusion, we discuss the frequently-used Wentzel-Kramers-Brillouin (WKB) method and the imaginary-time method (ITM). For static external electric fields, we find that these methods predict significant enhancement to the fusion cross section for electric-field strengths $&gt;{10}^{14}$ V/m, especially at low values ($\ensuremath{\approx}$ keV) for the enter-of-mass (CoM) energy. When considering dynamic electric fields, this enhancement can be amplified by considering increased photon frequencies. However, we also provide a review of the region of laser-parameter phase space where these semiclassical methods are applicable. We conclude that this allowable region decreases for higher photon frequencies in conjunction with lower values for the electric-field strength, motivating the need for future experiments to test the predictions of these methods and their ranges of validity.

Mapping Lamb, Stark, and Purcell Effects at a Chromophore-Picocavity Junction with Hyper-Resolved Fluorescence Microscopy

The interactions of the excited states of a single chromophore with static and dynamic electric fields spatially varying at the atomic scale are investigated in a joint experimental and theoretical effort. In this configuration, the spatial extension of the fields confined at the apex of a scanning tunneling microscope tip is smaller than that of the molecular exciton, a property used to generate fluorescence maps of the chromophore with intramolecular resolution. Theoretical simulations of the electrostatic and electrodynamic interactions occurring at the picocavity junction formed by the chromophore, the tip, and the substrate reveal the key role played by subtle variations of Purcell, Lamb, and Stark effects. They also demonstrate that hyper-resolved fluorescence maps of the line shift and linewidth of the excitonic emission can be understood as images of the static charge redistribution upon electronic excitation of the molecule and as the distribution of the dynamical charge oscillation associated with the molecular exciton, respectively.6 MoreReceived 30 April 2021Revised 29 September 2021Accepted 3 November 2021DOI:https://doi.org/10.1103/PhysRevX.12.011012Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI.Published by the American Physical SocietyPhysics Subject Headings (PhySH)Research AreasElectroluminescencePlasmonicsTechniquesFirst-principles calculationsScanning tunneling microscopyCondensed Matter, Materials & Applied PhysicsAtomic, Molecular & Optical

Scattering of SH guided wave by a circular cavity and a semicircular salient in an infinite piezoelectric strip

In this article, the problem of a salient with complex boundary conditions in a piezoelectric strip is studied by Fourier series expansion method, and SH guided wave is considered as an external load acting on piezoelectric strip. First, on the basis of repeated image superposition, the analytical expression of scattering wave is conducted, which satisfies the stress free and electric insulation conditions on the upper and lower horizontal boundaries of the strip. Next, with the aid of boundary condition, integral equations are setup and solved by applying orthogonal function expansion technique and effective truncation. Results clarified the influence on the dynamic stress concentration factor and electric field intensity concentration factor under proper conditions. Besides, the analytical solutions are compared with the finite element solutions to verify the accuracy of the conclusions in this article.

Dynamic anti-plane analysis for an elliptic inclusion in an infinite piezoelectric strip

Dynamic incident anti-plane shearing (SH guided wave) is considered to calculate dynamic stress and electric intensity in an infinite piezoelectric strip that contains an elliptic inclusion. By the means of the conformal mapping method, the field of an ellipse can be transformed into a unit circle. With the aid of series expansion method, the expression of SH guided wave is established, which satisfies the stress-free and electric insulation conditions on the upper and lower horizontal boundaries of the strip. The expression of scattering waves is conducted based on repeated image superposition. Boundary conditions are solved by applying the orthogonal function expansion technique. Results clarified the influence on the dynamic stress concentration factor and electric field intensity concentration factor under proper conditions.

Time-domain dynamic electric field distribution of low-oscillation sculptured structure dispersive mirrors

The dispersion oscillation and damage threshold of a dispersive mirror (DM) are the key influencing factors for high-quality pulses and outputting high power density. Here, we studied the femtosecond damage behavior of low-oscillation DMs(LODM) with SiO2 sculptured layer. The monochromatic standing wave field(SWF) distribution widely used in ultrafast laser damage analysis is sufficient in Bragg mirror. In more complex systems, the actual electric field intensity(typically smaller) will dynamically change due to the broad bandwidth and the time difference of pulse propagation. Time-domain dynamic electric field intensity displays that the spatio-temporal evolution of the pulse within the stacks averages the electric field intensity, especially the electric field in the deeper layers. The dynamic effect of few-cycle pulses or attosecond pulses damage will be more meaningful. The time-domain dynamic electric field model can elucidate the ultrafast laser damage behavior. Introducing the time-domain dynamic electric model into the merit function can help us design optical coatings with high damage thresholds.

The Effect of the Side Edge on the Plasma Current during Interactions between a Cold Plasma and a Metal Object

Plasma current behavior is affected by interactions between a cold plasma and a metal object. The plasma charge depends on the surface area of the metal object, which does not provide information regarding the shape of the object. A metal disk has a side edge and a square metal plate has corners. The edge effects associated with the metal disk and plate reflect the relationship between the plasma current and the dynamic electric field due to temporal variation of the applied voltage. When the object has a small surface area, the plasma current is inversely proportional to the dynamic electric field because the side edge is affected. The linear correlation between the plasma current and the dynamic electric field is disrupted by the edge effect. When a metal plate surface area is small, the plasma current does not depend on the dynamic electric field due to the effect of corners.

Determining Collision Cross Sections from Differential Ion Mobility Spectrometry.

The experimental determination of ion-neutral collision cross sections (CCSs) is generally confined to ion mobility spectrometry (IMS) technologies that operate under the so-called low-field limit or those that enable empirical calibration strategies (e.g., traveling wave IMS; TWIMS). Correlation of ion trajectories to CCS in other non-linear IMS techniques that employ dynamic electric fields, such as differential mobility spectrometry (DMS), has remained a challenge since its inception. Here, we describe how an ion's CCS can be measured from DMS experiments using a machine learning (ML)-based calibration. The differential mobility of 409 molecular cations (m/z: 86-683 Da and CCS 110-236 Å2) was measured in a N2 environment to train the ML framework. Several open-source ML routines were tested and trained using DMS-MS data in the form of the parent ion's m/z and the compensation voltage required for elution at specific separation voltages between 1500 and 4000 V. The best performing ML model, random forest regression, predicted CCSs with a mean absolute percent error of 2.6 ± 0.4% for analytes excluded from the training set (i.e., out-of-the-bag external validation). This accuracy approaches the inherent statistical error of ∼2.2% for the MobCal-MPI CCS calculations employed for training purposes and the <2% threshold for matching literature CCSs with those obtained on a TWIMS platform.

The Effects of Electric Field Dynamics on the Quality of Large-Area Nanofibrous Layers.

This paper presents technological modifications of an electrostatic spinning device, which significantly increase the thickness homogeneity (i.e., quality) of produced layers by creating auxiliary dynamic electric fields in the vicinity of the spinning and collector electrodes. A moving body was installed above the needleless spinning electrode, which destabilized the standing wave occurring on the free surface of the spinning solution. Furthermore, an endless belt design was used for the collector electrode instead of a roll-to-roll design, which made it possible to substantially increase the surface speed of the substrate and, therefore, the dynamics of the electric field at the place of collection of the fibers being spun. As a result, the coefficient of variation of the area weight of 912 samples cut out from the deposited nanofibrous layer, which was (1000 × 500) mm2 in size and had an average area weight of (17.2 ± 0.8) g/m2, was less than 4.5%. These results were obtained only when the dynamics of both the spinning and collector electrodes were increased at the same time. These modifications resulted in a significant increase in the quality of deposited nanofibrous layers up to the standard required for their use in pharmaceutical applications.

Phosphate Vibrations Probe Electric Fields in Hydrated Biomolecules: Spectroscopy, Dynamics, and Interactions.

Electric interactions have a strong impact on the structure and dynamics of biomolecules in their native water environment. Given the variety of water arrangements in hydration shells and the femto- to subnanosecond time range of structural fluctuations, there is a strong quest for sensitive noninvasive probes of local electric fields. The stretching vibrations of phosphate groups, in particular the asymmetric (PO2)− stretching vibration νAS(PO2)−, allow for a quantitative mapping of dynamic electric fields in aqueous environments via a field-induced redshift of their transition frequencies and concomitant changes of vibrational line shapes. We present a systematic study of νAS(PO2)− excitations in molecular systems of increasing complexity, including dimethyl phosphate (DMP), short DNA and RNA duplex structures, and transfer RNA (tRNA) in water. A combination of linear infrared absorption, two-dimensional infrared (2D-IR) spectroscopy, and molecular dynamics (MD) simulations gives quantitative insight in electric-field tuning rates of vibrational frequencies, electric field and fluctuation amplitudes, and molecular interaction geometries. Beyond neat water environments, the formation of contact ion pairs of phosphate groups with Mg2+ ions is demonstrated via frequency upshifts of the νAS(PO2)− vibration, resulting in a distinct vibrational band. The frequency positions of contact geometries are determined by an interplay of attractive electric and repulsive exchange interactions.

Demonstration of the trapped-ion quantum CCD computer architecture.

The trapped-ion quantum charge-coupled device (QCCD) proposal1,2 lays out a blueprint for a universal quantum computer that uses mobile ions as qubits. Analogous to a charge-coupled device (CCD) camera, which stores and processes imaging information as movable electrical charges in coupled pixels, a QCCD computer stores quantum information in the internal state of electrically charged ions that are transported between different processing zones using dynamic electric fields. The promise of the QCCD architecture is to maintain the low error rates demonstrated in small trapped-ion experiments3-5 by limiting the quantum interactions to multiple small ion crystals, then physically splitting and rearranging the constituent ions of these crystals into new crystals, where further interactions occur. This approach leverages transport timescales that are fast relative to the coherence times of the qubits, the insensitivity of the qubit states of the ion to the electric fields used for transport, and the low crosstalk afforded by spatially separated crystals. However, engineering a machine capable of executing these operations across multiple interaction zones with low error introduces many difficulties, which have slowed progress in scaling this architecture to larger qubit numbers. Here we use a cryogenic surface trap to integrate all necessary elements of the QCCD architecture-a scalable trap design, parallel interaction zones and fast ion transport-into a programmable trapped-ion quantum computer that has a system performance consistent with the low error rates achieved in the individual ion crystals. We apply this approach to realize a teleported CNOT gate using mid-circuit measurement6, negligible crosstalk error and a quantum volume7 of 26=64. These results demonstrate that the QCCD architecture provides a viable path towards high-performance quantum computers.

Static Schwinger-Level Electric Field Nonlinearities and Their Significance to Photons and Photon Entanglement

In this work, we postulate that Schwinger’s threshold for a dynamic electric field intensity to induce spatial nonlinearity is a special case and, more generally, it is the threshold field for both static and dynamic electric fields. Fields of this magnitude induce negative-energy charges to adapt positive energy attributes; within an atom, they also support interstate energy transfers and intrastate chaotic mixing of time-varying fields. Nonlinearity-induced chaos forms the basis for the probabilistic nature of photon creation. Answers to physical problems at atomic and lower scales continuously evolve because chaotic-like electron movements change their configurations on a time scale of 10 zs. Within atoms, frequency mixing that creates an optical frequency field occurs in the nonlinear region surrounding the nucleus. On a probabilistic basis, a ring of vacuum charge can be induced that forms into an equivalent waveguide, which confines the energy as it travels permanently away from the atom. The propagating relativistically augmented fields losslessly induce charges that bind and protect the energy-carrying fields. The photon charge-field ensemble is a closed system and possesses all first-order photon properties, including zero rest mass and permanent stability. For near-neighbor photons traveling at a speed approaching c, we find a small constant force between them that is dependent upon their relative spin orientations. Our model shows that the radius of a photon is ≈10 am and that photon wavelength information is coded by energy.

Numerical investigation of plasma characteristics for an ion thruster discharge chamber

A 2D fully kinetic particle-in-cell plus Monte Carlo collision model is developed to simulate the plasma characteristics of the ion thruster discharge chamber. The interaction between charged particles and the dynamic electric field, the confinement of the static magnetic field, and the particle collisions are simulated. The self-similar scaling method, the multigrid method, sub-cycle time, and neutral particle pre-distribution techniques work together to perform the full-particle and full-kinetic simulation. The steady-state results such as particle number, current flows, static magnetic field, electric potential, particle density, and energy distributions are obtained and discussed. Moreover, the plasma generation and transport, the dynamic behavior of neutral particles, and the influence of the gas flow rate on the plasma are analyzed. The density distribution of charged particles indicates that the electrons are strongly constrained by the magnetic field, and the magnetization characteristics are distinguished from that of ions. Neutral particles are heavily ionized and are depleted along the central line, which is consistent with the area with a higher ionization rate. At last, it is found that the energy and density of charged particles are sensitive to the change of the gas flow rate.