Effective Charging Energy Research Articles

Energy management of renewable energy connected electric vehicles charging using Internet of things: Hybrid MRA-SDRN approach

This manuscript presents a novel hybrid technique, termed the MRA-SDRN method, for optimizing renewable energy-based electric vehicle (EV) charging within an Internet of Things (IoT) architecture. The key objective is to enhance the efficiency of PV-connected EV systems while concurrently reducing electricity costs and pollutant emissions. The MRA-SDRN approach leverages the Mud Ring Algorithm (MRA) and the Spiking Deep Residual Network (SDRN) to optimize several parameters critical for effective EV charging and renewable energy utilization. Comparative analysis with existing techniques conducted in MATLAB demonstrates notable reductions in computation time, with the MRA-SDRN method achieving a calculation time of 13.04 s, outperforming simulated annealing (SA), multi-objective particle swarm optimization and genetic algorithms (GA).Additionally, significant decreases in pollutant emissions are observed, with levels measured at 472.38 g compared to 570.48 g for GA, 528.35 g for SA, and 502.01 g for MOPSO. Regarding electricity costs, the MRA-SDRN approach achieves a competitive rate of 0.306 yuan/kWh, emphasizing its cost-effectiveness. These numerical results underscore the efficacy of the MRA-SDRN method in optimizing renewable energy management for EV charging, thereby contributing to enhanced reliability, efficiency, and sustainability in the transportation sector within the IoT framework.

A highly energy-efficient magnetoelectric–photocatalytic coupling for water remediation

Contaminated water is one of the main infection routes for serious diseases, and water remediation of different environmental contaminations is an urge today. Here, we introduce a novel high-μ ribbon FeBSi–ZnO magnetoelectric (ME) nanocomposite that exhibits a magnetoelectric–photocatalytic (MEPC) coupling effect, which further enhances electrochemical activity for water remediation. Compared to the previously reported ultrasonic piezoelectric-photocatalytic technique, the proposed MEPC coupling system is 100–1200 times more energy-efficient. This energy-efficient catalysis can be attributed to the effective charge energy shifting generated by the low-power MEPC coupling system, which promotes the surface redox reaction via transferred electrons and holes and generation of the reactive oxygen species of •O−2 and •OH. It is also found that the kinetic rate of organic pollutant degradation under MEPC activity is approximately three times faster than that of a pure PC process. The degradation efficiency for indigo carmine (IC), methyl orange (MO), and rhodamine B (RB) organic pollutants is 98% (less than 60 min), 97%, and 92% within 120 min, respectively. Also, MEPC activity could conduct 99.9% reduction of E. coli bacteria within 30 min. This study, therefore, provides an original MEPC system and an effective strategy for the sustainable environmental remediation endowed with an energy-efficient and low-cost nature owing to the multiphysical field synergetic effect.

G -factors in LaAlO3/SrTiO3 quantum dots

We investigate the $g$-factors of individual electron states in gate-defined quantum dots fabricated from ${\mathrm{LaAlO}}_{3}/{\mathrm{SrTiO}}_{3}$ heterostructures. We consider both the case of effective positive charging energy ($Ug0$) where single electrons are added upon increasing the local gate voltage, and the case of $Ul0$ where electron pairing is observed. The $g$-factors are extracted from the field dependence of the quantum dot addition spectrum. Tunnel couplings and confinement are tunable by the gate voltages and in the regime of weakest coupling, we find $g$-factors close to 2 due to quenching of the orbital magnetic moment. For stronger coupling, $g$-factors are anisotropic and exhibit values up to $\ensuremath{\sim}4.5$ in the out-of-plane orientation. We further show examples of the sequential addition of electrons with the same spin as a consequence of exchange interactions.

Zeta Potential Prediction from Protein Structure in General Aqueous Electrolyte Solutions.

The ζ, or electrokinetic, potential is the effective charge energy of a molecule in a solution, defining its electrostatic interactions in the solution. A computational protocol for computing ζ potential from the high-resolution structures of proteins (ZPRED) is described. This model considers both protein and solution components and incorporates a number of electrokinetic models that account for many of the complexities of protein electrophoresis. Experimental observations of electrophoretic mobilities using a benchtop light scattering instrument match computed mobilities for different proteins over a wide range of aqueous solution conditions. ZPRED is a tool for optimizing protein sequence and solution conditions (pH, ionic composition and strength, temperature) to disperse molecules by charge repulsion, preventing aggregation. This is an important factor in enhancing the stability of engineered biologics or industrial protein catalysts.

Analytical estimate of effective charge and ground-state energy of beryllium atom utilizing variational method

In this paper, we present an analytical procedure to determine the effective charge and ground-state energy of a four-electron beryllium atom. The procedure followed is based on a variant of variational technique using modified hydrogenic one-electron wave function to calculate effective charge in 1s and 2s states of beryllium atom. The effective charge in 1s state is 3.68609 and in 2s state is 1.82362. Further, we have used these values in non-relativistic Hamiltonian with interaction terms to calculate the ground-state energy of beryllium atom. The estimated value of ground-state energy (− 14.3423 au) is in good agreement with the experimental results and with other theoretically obtained values. The calculated results without using any computationally intensive technique are the essence of this research work.

Influence of Trivalent Metal Ions on Lipid Vesicles: Gelation and Fusion Phenomena.

In this contribution, we report the interaction of 1,2-dimyristoyl- sn-glycero-3-phosphocholine (DMPC)lipid vesicles with a series of trivalent metal ions of the same group, namely, Al3+, Ga3+, and In3+, to get a distinct view of the effect of size, effective charge, and hydration free energy of these metal ions on lipid vesicles. We employed steady-state and time-resolved spectroscopic techniques including time-resolved anisotropy measurement, confocal imaging, and dynamic light scattering (DLS) measurement to probe the interaction. Our study reveals that all of the three trivalent metal ions induce gelation in lipid vesicles by removing water molecules from the interfacial region. The extent of gelation induced by the metal ions follows the order of In3+ > Ga3+ ≥ Al3+. We explain this observation in light of different free-energy terms. Notably, the degree of interaction for trivalent metal ions is higher as compared to that for divalent metal ions at physiological pH (pH ∼ 7.0). Most importantly, we observe that unlike divalent metal ions, trivalent metal ions dehydrate the lipid vesicles even at lower pH. The DLS measurement and confocal imaging indicate that In3+ causes significant aggregation or fusion of the PC vesicles, while Al3+ and Ga3+ did not induce any aggregation at the experimental concentration. We employ Derjaguin-Landau-Vervey-Overbeek (DLVO)theory to explain the aggregation phenomena induced by In3+.

Hydrodynamic radius coincides with the slip plane position in the electrokinetic behavior of lysozyme.

The zeta potential (ζ) is the effective charge energy of a solvated protein, describing the magnitude of electrostatic interactions in solution. It is commonly used in the assessment of adsorption processes and dispersion stability. Predicting ζ from molecular structure would be useful to the structure-based molecular design of drugs, proteins, and other molecules that hold charge-dependent function while remaining suspended in solution. One challenge in predicting ζ is identifying the location of the slip plane (XSP ), a distance from the protein surface where ζ is theoretically defined. This study tests the hypothesis that the XSP can be estimated by the Stokes-Einstein hydrodynamic radius (Rh ), using globular hen egg white lysozyme as a model system. Although the XSP and Rh differ in their theoretical definitions, with the XSP being the position of the ζ during electrokinetic phenomena (e.g., electrophoresis) and the Rh being a radius pertaining to the edge of solvation during diffusion, they both represent the point where water and ions no longer adhere to a molecule. This work identifies the limited range of ionic strengths in which the XSP can be determined using diffusivity measurements and the Stokes-Einstein equation. In addition, a computational protocol is developed for determining the ζ from a protein crystal structure. At low ionic strengths, a hyperdiffusivity regime exists, requiring direct measurement of electrophoretic mobility to determine ζ. This work, therefore, supports a basic tenant of EDL theory that the electric double layer during diffusion and electrophoresis are equivalent in the Stokes-Einstein regime.

Radiation Constrained Scheduling of Wireless Charging Tasks

This paper studies the problem of Radiation cOnstrained scheduling of wireless Charging tasKs (ROCK), that is, given wireless charging tasks with required charging energy and charging deadline for rechargeable devices, scheduling the power of wireless chargers to maximize the overall effective charging energy for all rechargeable devices, and further to minimize the total charging time, while guaranteeing electromagnetic radiation (EMR) safety, i.e., no point on the considered 2-D area has EMR intensity exceeding a given threshold. To address ROCK, we first present a centralized algorithm. We transform ROCK from nonlinear problem to linear problem by applying two approaches of area discretization and solution regularization, and then propose a linear programming-based greedy test algorithm to solve it. We also propose a distributed algorithm that is scalable with network size by presenting an area partition scheme and two approaches called area-scaling and EMR-scaling, and prove that it achieves effective charging energy no less than (1- ε) of that of the optimal solution, and charging time no more than that of the optimal solution. We conduct both simulation and field experiments to validate our theoretical findings. The results show that our algorithm achieves 94.9% of the optimal effective charging energy and requires 47.1% smaller charging time compared with the optimal one when ε ≥ 0.2, and outperforms the other algorithms by at least 350.1% in terms of charging time with even more effective charging energy.

Ab initio electronic structure, bonding and optical properties of two relatively new ceramics Hf2Al3C4 and Hf3Al3C5: A comparative study

The structural, electronic and optical properties of the ternary carbides Hf2Al3C4 and Hf3Al3C5 are studied via first principles orthogonalized linear combination of atomic orbitals (OLCAO) method. Results on crystal structure, interatomic bonding, band structure, total and partial density of states (DOS), localization index (LI), effective charge (Q*), bond order (BO), dielectric function (ε), optical conductivity (σ) and electron energy loss function are presented and discussed in detail. The band structure plots show the conducting nature of Hf2Al3C4 and Hf3Al3C5 carbides. DOS results disclose that the total number of states at Fermi level N(EF) are 1.89 and 2.38 states/(eV unit cell) for Hf2Al3C4 and Hf3Al3C5 respectively. The Q* calculations show an average charge transfer of 0.723 and 0.711 electrons from Hf and 0.809 and 0.807 electrons from Al to C sites in Hf2Al3C4 and Hf3Al3C5 respectively. The BO results provide the dominating role of Al–C bonds with BO value of 6.62 (BO% = 59%) and 6.66 (BO% = 49%) for Hf2Al3C4 and Hf3Al3C5 respectively and are considered responsible for the crystals cohesion. The LI results reflect the presence of highly delocalized states in the vicinity of the Fermi level. The dielectric function plots of the real (ɛ1(ℏω)) and imaginary (ɛ2(ℏω)) parts show the anisotropic behavior of Hf2Al3C4 and Hf3Al3C5. The results on optical conductivity (σ) support the trends observed in dielectric functions. The electron energy loss functions reveal the presence of sharp peaks both in ab-plane and along c-axis around 20 eV in Hf2Al3C4 and Hf3Al3C5 ternary carbides.

Multi-Level Kondo Effect and Enhanced Critical Temperature in Nanoscale Granular Al

The normal state conductance of high resistivity granular Al films, having an enhanced critical temperature above 3 K, shows a non-monotonous temperature dependence. Upon cooling the conductance first increases, reaches a broad maximum, then decreases, and finally increases sharply again at low temperatures. This behavior bears a striking resemblance to that predicted for the conductance of quantum dots in a regime where the broadening of discrete energy levels, due to coupling of the dot to the leads reservoirs, is larger than the level separation. In this regime, a multi-level Kondo temperature can be larger than the effective Coulomb charging energy, leading to a metallic-like behavior at high temperatures. This is followed by a Coulomb dominated regime, while at yet lower temperatures, the single level Kondo behavior can be recovered. We believe that this multi-level Kondo resonance model for single dots may apply to our 3D network of nanoscale grains. The multi-level resonance prevents the insulating state from setting-in already at high temperatures, which is favorable for superconductivity. This interpretation of the experimental conductance data is in line with the previously reported presence of magnetic moments in these films. High-resolution electron microscopy shows that intergrain coupling can take place through atomic size Sharvin contacts, which is consistent with the typical values of the intergrain resistance of the films as the metal to insulator transition is approached.

Effective capacitance of the metallic single electron transistor: a path integral Monte Carlo study

We proposed a method to calculate the effective capacitance of a metallic single-electron transistor using the quantum Monte Carlo method to describe the Coulomb blockade effect. The effective capacitance depended on the induced gate charge, temperature, and conductance of the system. Furthermore, the results can be used to calculate the effective charging energy, which has been characterizing the strength of the Coulomb blockade effect. In the Coulomb blockade regime, the effective charging energy was approximately equal to charging energy. In particularly, the effective charging energy decreased with an increase in the conductance and temperature.

Transport and excitations in a negative-U quantum dot at the LaAlO3/SrTiO3 interface

In a solid-state host, attractive electron–electron interactions can lead to the formation of local electron pairs which play an important role in the understanding of prominent phenomena such as high Tc superconductivity and the pseudogap phase. Recently, evidence of a paired ground state without superconductivity was demonstrated at the level of single electrons in quantum dots at the interface of LaAlO3 and SrTiO3. Here, we present a detailed study of the excitation spectrum and transport processes of a gate-defined LaAlO3/SrTiO3 quantum dot exhibiting pairing at low temperatures. For weak tunneling, the spectrum agrees with calculations based on the Anderson model with a negative effective charging energy U, and exhibits an energy gap corresponding to the Zeeman energy of the magnetic pair-breaking field. In contrast, for strong coupling, low-bias conductance is enhanced with a characteristic dependence on temperature, magnetic field and chemical potential consistent with the charge Kondo effect.

Quantum charge fluctuations of a proximitized nanowire

Motivated by recent experiment, we consider charging of a nanowire which is proximitized by a superconductor and connected to a normal-state lead by a single-channel junction. The charge $Q$ of the nanowire is controlled by gate voltage $e{\cal N}_g/C$. A finite conductance of the contact allows for quantum charge fluctuations, making the function $Q(\mathcal{N}_g)$ continuous. It depends on the relation between the superconducting gap $\Delta$ and the effective charging energy $E^*_C$. The latter is determined by the junction conductance, in addition to the geometrical capacitance of the proximitized nanowire. We investigate $Q(\mathcal{N}_g)$ at zero magnetic field $B$, and at fields exceeding the critical value $B_c$ corresponding to the topological phase transition. Unlike the case of $\Delta = 0$, the function $Q(\mathcal{N}_g)$ is analytic even in the limit of negligible level spacing in the nanowire. At $B=0$ and $\Delta>E^*_C$, the maxima of $dQ/d\mathcal{N}_g$ are smeared by $2e$-fluctuations described by a single-channel "charge Kondo" physics, while the $B=0$, $\Delta<E^*_C$ case is described by a crossover between the Kondo and mixed-valence regimes of the Anderson impurity model. In the topological phase, $Q(\mathcal{N}_g)$ is analytic function of the gate voltage with $e$-periodic steps. In the weak tunneling limit, $dQ/d\mathcal{N}_g$ has peaks corresponding to Breit-Wigner resonances, whereas in the strong tunneling limit (i.e., small reflection amplitude $r$ ) these resonances are broadened, and $dQ/d\mathcal{N}_g-e \propto r\cos(2\pi \mathcal{N}_g)$.

Design Considerations for Wireless Charging Systems with an Analysis of Batteries

Three criteria, including charging time, effective charging capacity and charging energy efficiency, are introduced to evaluate the CC (constant current) and CC/CV (constant current/constant voltage) charging strategies. Because the CC strategy presents a better performance and most resonant topologies have the CC characteristic, the CC strategy is more suitable for the design of wireless charging systems than the CC/CV strategy. Then, the state space model of the receiver is built to study the system dynamic characteristics, and the design of nonuse output filter capacitors is proposed, which can improve the system power density and avoid the drop in efficiency caused by capacitor degradation. At last, an electrochemical impedance spectrum (EIS) based analysis method is introduced to validate that the design without output filter capacitors has no effects on the battery characteristics when the charging frequency is higher than 460 Hz. A prototype is fabricated to verify our research results.

Structural Evolution of Reduced Graphene Oxide of Varying Carbon sp2 Fractions Investigated via Coulomb Blockade Transport

We investigate the structural evolution of reduced graphene oxide (RGO) sheets with carbon sp2 fractions varying from 55 to 80% using low-temperature Coulomb blockade (CB) transport. At 4.2 K, all RGO sheets exhibit a complete suppression of current (CB) below a threshold voltage Vt, the value of which decreased from 3.34 to 0.25 V with increasing carbon sp2 fraction. From the temperature-dependent Vt, we calculate an effective charging energy and individual graphene domain size of 160 meV and 1.34 nm at 55% carbon sp2 fractions, respectively. These values are 20 meV and 4.18 nm at 80% carbon sp2 fractions, respectively. This implies that with increasing reduction, newly formed sp2 domains increase the effective size of the graphene domain. For an applied voltage V > Vt, the current I follows a scaling law I ∼ [(V – Vt)/Vt]α where the scaling parameter α increases from 2.11 to 3.40 with increasing sp2 fraction, suggesting that increasing sp2 fraction creates more topological defects on the RGO. Our report provides a much desired insight into the structural evolution of RGO sheets.

Coulomb Energy Determination of a Single Si Dangling Bond

Determination of the Coulomb energy of single point defects is essential because changing their charge state critically affects the properties of materials. Based on a novel approach that allows us to simultaneously identify a point defect and to monitor the occupation probability of its electronic state, we unambiguously measure the charging energy of a single Si dangling bond with tunneling spectroscopy. Comparing the experimental result with tight-binding calculations highlights the importance of the particular surrounding of the localized state on the effective charging energy.

Thermal transport of molecular junctions in the pair tunneling regime

Charge and heat transport through a single molecule tunnel-coupled to external normal electrodes have been studied. The molecule with sufficiently strong interaction between lectrons and vibrational internal degrees of freedom can be characterized by the negative effective charging energy U$<0$. Such a molecule has been considered and modeled by the Anderson Hamiltonian. The electrical conductance, thermopower and thermal conductance of the system have been calculated as a function of gate voltage in the weak coupling limit within the rate equation approach. In the linear regime the analytic formulae for the transport coefficients in the pair dominated tunneling are presented. The effects found in the nonlinear transport include {\it inter alia} the rectification of the heat current. The sense of forward (reverse) direction, however, depends on the tuning parameter and can be controlled by the gate voltage. We also discuss the quantitation of the thermal conductance and the departures from the Wiedemann-Franz law.

Electromechanical instability in vibrating quantum dots with effectively negative charging energy

In quantum dots or molecules with vibrational degrees of freedom the electron-vibron coupling renormalizes the electronic charging energy. For sufficiently strong coupling, the renormalized charging energy can become negative. Here, we discuss an instability toward adding or removing an arbitrary number of electrons when the magnitude of the renormalized charging energy exceeds the single-particle level spacing. We show that the instability is regularized by the anharmonic contribution to the vibron energy. The resulting effective charging energy as a function of the electron number has a double-well structure causing a variety of novel features in the Coulomb-blockade properties.

Phonon-assisted spin-polarized tunneling through an interacting quantum dot

Using the nonequilibrium Green function technique we study theoretically spin-polarizedtransport in double-barrier tunneling junctions based on a single-level quantum dotinteracting with a local phonon mode. Phonon emission and absorption spectra have beencalculated for arbitrary Coulomb correlations on the dot and for different temperatures. Itis shown that in the nonlinear response regime the electron–phonon interaction gives rise tocurrent suppression in symmetric junctions as well as to oscillations of the tunnelmagnetoresistance (TMR). In asymmetric junctions, the same mechanism may leadeffectively to enhancement of the diode-like characteristics. We have also found that atsufficiently low temperatures additional phonon-induced resonance peaks appear in thelinear spectral function on both sides of the main resonance peaks corresponding to thequantum dot energy levels. The case of negative effective charging energy is also analyzednumerically. A significant enhancement of electric current (or suppression of TMR) abovethe threshold bias voltages at which the dot energy level enters the tunneling window isobserved. The gate voltage-controlled rectification effect of the tunneling current inasymmetric junctions with positive and negative effective Coulomb correlations is alsodiscussed.

Characterization of Multistep Electron Charging and Discharging of a Silicon Quantum Dots Floating Gate by Applying Pulsed Gate Biases

Electron charging and discharging operations for a silicon quantum dots (Si-QDs) floating gate with discrete charged states were characterized in n-metal–oxide–semiconductor field-effect-transistors (MOSFETs) by applying single-pulsed gate biases Vg with pulse widths ranging from 10 ns to 100 ms. The drain current levels for charged states increase stepwise with Vg pulse width, which indicates multistep electron charging in the Si-QDs floating gate due to quantization energy and electron charging. The gate voltages required to minimize the time for charging and discharging the Si-QDs floating gate are limited by the leakage current through the control oxide, which partially compensates the charging or discharging current through the tunnel oxide in the high-gate-voltage region. The transient variation of the drain current at zero gate bias, after the application of pulsed gate biases for the dot floating gate to be charged, shows that a critical transition from an unstable charged state to a stable one occurs, depending on the pulse height or width. This suggests the redistribution of electrons in the floating gate during the metastable state, which involves a reduction in the effective charging energy and the resultant elimination of the Coulomb blockade.