Charge Coupling Research Articles

Carrollian motion in magnetized black hole horizons

We revisit the motion of massless particles with anyonic spin in the horizon of Kerr-Newman geometry. As recently shown, such particles can move within the horizon of the black hole due to the coupling of charges associated with a two-parametric central extension of the two-dimensional Carroll group to the magnetic field generated by the black hole---the so-called ``anyonic spin-Hall effect.'' We show that the previously computed magnetic field is not invariant under Carroll diffeomorphisms and find another result which respects these symmetries of the horizon. We also consider a more astrophysically relevant case of a (weakly charged) rotating back hole placed in a uniform magnetic field, which could, for instance, be induced by the surrounding plasma. We show that a qualitatively similar magnetic field assisted anyonic spin-Hall effect takes place, even in the absence of black hole rotation. The theoretical possibility of a motion induced by a magnetic monopole is also studied.

Electrical Charge Coupling Dominates the Hysteresis Effect of Halide Perovskite Devices.

Hysteresis effects in ionic-electronic devices are a valuable resource for the development of switching memory devices that can be used in information storage and brain-like computation. Halide perovskite devices show frequent hysteresis in current-voltage curves that can be harnessed to build effective memristors. These phenomena can be often described by a set of highly nonlinear differential equations that involve current, voltage, and internal state variables, in the style of the famous Hodgkin-Huxley model that accounts for the initiation and temporal response of action potentials in biological neurons. Here we extend the neuron-style models that lead to chemical inductors by introducing a capacitive coupling in the slow relaxation variable. The extended model is able to explain naturally previous observations concerning the transition from capacitor to inductor in impedance spectroscopy of MAPbBr solar cells and memristors in the dark. The model also generates new types of oscillating systems by the generation of a truly negative capacitance distinct from the usual inductive effect.

Flame stability measurement through image moments and texture analysis

In this article, the first two moments of the image, mean and standard deviation, uniform local binary pattern (LBP) texture analysis methods were experimentally investigated in coal-fired boilers to measure flame stability. The first two moments of the flame image were used to evaluate the flame stability in terms of color and brightness (average gray value). Although the radiation signal of the flame is widely obtained by the spectral analysis method, the radiation signal of the flame was obtained by the LBP texture analysis method in this study. The flame stability measurement technique proposed in this study does not require prior knowledge about charged coupling devices camera features. Therefore, it can be easily applied to measure flame stability without expensive and complicated adaptation processes. Flame stability was measured with R = 0.9868 accuracy with the proposed method. The experimental results show that the proposed texture analysis method is more effective than current spectral analysis methods. The results obtained within the scope of this study also show that it can be easily applied to existing closed-loop control systems to monitor flame stability.

Solid‐State Homojunction Electrochemical Transistors and Logic Gates on Plastic

AbstractOrganic electrochemical transistors (OECTs) have attracted significant attention due to their unique ionic–electronic charge coupling, which holds promise for use in a variety of bioelectronics. However, the typical electronic components of OECTs, such as the rigid metal electrodes and aqueous electrolytes, have limited their application in solid‐state bioelectronics that requires design flexibility and a variety of form factors. Here, the fabrication of a solid‐state homojunction OECT consisting of a pristine polymer semiconductor channel, doped polymer semiconductor electrodes, and a solid electrolyte is demonstrated. This structure combines the photo‐crosslinking of all of the electronic OECT components with the selective doping of the polymer semiconductor. Three Lewis acids (gold (III) chloride (AuCl3), iron (III) chloride (FeCl3), and copper (II) chloride (CuCl2) ) are utilized as dopants for the metallization of the polymer semiconductor. The AuCl3‐doped polymer semiconductor with an electrical conductivity of ≈100 S cm−1 is successfully employed as the source, drain, and gate electrodes for the OECT, which exhibited a high carrier mobility of 3.4 cm2 V−1 s−1 and excellent mechanical stability, with negligible degradation in device performance after 5000 cycles of folding at a radius of 0.1 mm. Homojunction OECTs are then successfully assembled to produce NOT, NAND, and NOR logic gates.

The grain growth mechanisms for 0.8(Bi,Na)TiO3-0.2(Sr,Ti)O3 ceramics prepared using a two-step sintering process

ABSTRACT In this study, lead-free 0.8(Bi,Na)TiO3-0.2(Sr,Ti)O3 piezoelectric ceramics were prepared using a two-step sintering process to analyze their sintering mechanisms. Two-step sintering process has benefits of being able to be conducted at lower temperatures than conventional sintering process, but the complicated sintering mechanisms involved in this process have not been yet fully investigated. Therefore, in the present study, two-step sintering mechanism for lead-free piezoelectric ceramics was analyzed by estimating the activation energy required depending on the sintering conditions. Using the two-step sintering process, the piezoelectric charge and electromechanical coupling coefficients improved from 146 pC/N and 0.347 to 163 pC/N and 0.377, respectively. By comparing the grain-growth mechanisms for the conventional and two-step sintering processes, it appeared that the sintering mechanisms differed. By introducing the two-step sintering process, piezoelectric ceramics with improved piezoelectric charge and electromechanical coupling coefficients were produced.

Green synthesis of cerium nanoparticles using hibiscus rosasinesis extract and evaluation of their antimicrobial activity and photocatalytic activity

A bio-mediated method was used to create spherical-shaped cerium dioxide (CeO2) nanoparticles (NPs) utilizing hibiscus Rosa-sinensis flower extract. Techniques including FT-IR, ZETA, XRD, SEM, and UV–Visible were used to characterize the NPs. The antibacterial and photo catalytic capabilities of NPs were investigated. The SEM findings show that the concentration of Hibiscus cerium extract in the reaction mixture had a significant impact on the NPs' shape. The FTIR analysis confirmed the phyto chemical involvement in NPs stabilization. Rhodamine-B (RhB) was used to measure the photocatalytic activity of NPs under UV and sunlight illumination. CeO2 NPs with 5 ml were shown to have better photocatalytic activity under both UV irradiations. Defect-induced bandgap-engineered CeO2 NPs were given credit for the improved photocatalytic activity and characteristics. Excellent breakdown performance is provided by CeO2 NPs', which also has antimicrobial surface activity. Furthermore, a better nanoparticle that functions as a charge divider to prevent charge coupling and improve the performance of photodegradation. It was discovered that adding biomaterial enhanced the efficacy of Rhodamine B breakdown with increased CeO2 doping. Under light irradiation, Rhodamine b breakdown decreased from 3.344 to 0.513 after 210 min. Additionally, CeO2 with 5 ml shows considerable antibacterial action against Staphylococcus aureus, Bacillus subtilis, and E. coli. These results demonstrate CeO2 NPs' significant potential as a versatile material for a variety of applications.

Bi-functional role of high charge mobility with 2D/2D interactions for effective PEC and visible photocatalysis in NiO/MoS2 nanocomposites

Bi-functional 2D–2D NiO/MoS2 exhibits superior photoactivity and hydrogen production due to homogenously dispersed layers, electronic conductivity, and interfacial charge coupling.

Tests of low-scale leptogenesis in charged lepton flavour violation experiments

We consider low-energy tests of low-scale leptogenesis based on the type I seesaw scenario with three right-handed singlet neutrinos νlR. In this scenario, successful leptogenesis is possible for quasi-degenerate in mass heavy Majorana neutrinos N1,2,3, M1,2,3≅M, |Mj−Mi|≪M, i≠j=1,2,3, heavy Majorana neutrino masses M∼(0.05−5×105) GeV, and Nj charged current and neutral current weak interaction couplings as large as O(10−2). We derive the constraints on the corresponding leptogenesis parameter space from the existing data from low-energy experiments, including the limits from the experiments on μ→eγ decay and on the rate of μ−e conversion in gold. We show also that the planned and upcoming experiments on charged lepton flavour violation with μ±, MEG II on the μ→eγ decay, Mu3e on μ→eee decay, Mu2e and COMET on μ−e conversion in aluminium and PRISM/PRIME on μ−e conversion in titanium, can probe significant region of the viable leptogenesis parameter space, and thus have a potential for a discovery. Experiments on τ→eee(μμμ) and τ→e(μ)γ decays (e.g., BELLE II) also can probe a part of the leptogenesis parameter space, although a relatively small one.

Нелинейно-оптические свойства кристаллов ниобата лития, легированных цинком

The coefficients of the second order nonlinear optical dij tensor were calculated by the method developed on the basis of the dielectrics theory of Phillipson and Van Wetchen and the Levin charge coupling model for lithium niobate crystals doped with zinc (3.43–5.84 mol %). In LiNbO3 : Zn crystals, the concentration dependences of the nonlinear optical coefficients showed several regions with maxima and minima; the most noticeable changes in the nonlinear optical coefficients were observed at threshold concentrations of zinc oxide in the melt. Doping with zinc increases the conversion efficiency of the second harmonic radiation, such the crystals are more promising for use in nonlinear optics than a nominally pure lithium niobate crystal.

Microchemical homogeneity and quenching-induced property enhancement in BiFeO3–BaTiO3 ceramics

BiFeO3–BaTiO3 (BF-BT) solid solutions are promising as the basis for high temperature dielectric and piezoelectric materials, but their microstructural aspects have received relatively little attention. This study evaluates the influence of different processing procedures on the micro-chemical heterogeneity and functional properties of 0.67BF-0.33BT ceramics prepared by solid state reaction. It is shown that the use of high energy planetary ball milling after calcination is an effective method to improve chemical homogeneity and circumvent the core-shell type features found in conventional vibration-milled materials. BF-BT ceramics prepared by high energy milling exhibit enhanced remnant polarization, piezoelectric charge coefficient and coupling factor values of 0.34C m−2, 105 pC/N and 0.24, in comparison with those of vibration milled materials (0.30 C m−2, 73 pC/N and 0.19 respectively). Further improvements in functional properties were achieved by application of an air quenching process, which also led to an increase of 50 °C in both the Curie point and depolarization temperature; these modifications were correlated with increased structural distortion and volume fraction of the rhombohedral phase. Quenched BF-BT ceramics also exhibited mixed inter- and trans-granular fracture modes, whereas that of the as-sintered materials was predominantly inter-granular.

Simulation Study of Accuracy of Calculated Single Photon Event Position with Sub-pixel Spatial Resolution in Charge Couple Device

It has been a long-term effort to get higher energy resolution for experiment detector. Usually the energy resolution can be converted from spatial resolution though mechanical setup. To shrink pixel size of detector takes a lot of efforts, time and is limited by integrated circuit technology. So centroid algorithm is widely used to increase spatial resolution. Through electron cloud diffusion, the excited electrons are distributed among nearby pixels. Using centroid algorithm, the photon impact point can be calculated. However, the accuracy of calculated position is affected by relative impact position within pixel and signal to noise ratio (SNR). There is a systematic bias offset, or edge effect, toward pixel center when the impact point is near perimeter of pixel. Also the SNR is an important factor which affects the accuracy of calculated position. In this study, we try to calculate the simulated photon event positions by three algorithms, 3x3 centroid, 5x5 centroid and two-dimensional Gaussian profile fit. A simulation 2000 x 1000 pixels’ image with specific SNR is filled with noise first and then sparsely and randomly distributed with 200 Gaussian shaped photon impact events to avoid pile up. Since the original impact points are well known, the calculated positions of photon event can be compared with the original data to verify their accuracy. The noise, or SNR, can also be adjusted for different images to see its effects on the accuracy. The simulation shows the systematic bias toward pixel center for centroid algorithm as seen in the previous experiment using 3x3 centroid. For 3x3 centroid, the bias will not disappear even when SNR is high. 5x5 centroid is better than 3x3 centroid when SNR is high but the position accuracy degrades faster when image SNR decreases. The 2D-Gaussian fit can provide better position estimation at the same SNR and systematic bias of position at perimeter of pixel is minimized. However, the iteration process will diverge and no optimized answer can be attained when SNR is too low. The accuracy of calculated position, defined as inverse of position error standard deviation, is proportional to SNR for 5x5 and 2-D Gaussian fit.

Single-domain stripe order in a high-temperature superconductor

The coupling of spin, charge and lattice degrees of freedom results in the emergence of novel states of matter across many classes of strongly correlated electron materials. A model example is unconventional superconductivity, which is widely believed to arise from the coupling of electrons via spin excitations. In cuprate high-temperature superconductors, the interplay of charge and spin degrees of freedom is also reflected in a zoo of charge and spin-density wave orders that are intertwined with superconductivity. A key question is whether the different types of density waves merely coexist or are indeed directly coupled. Here we profit from a neutron scattering technique with superior beam-focusing that allows us to probe the subtle spin-density wave order in the prototypical high-temperature superconductor La{}_{1.88}Sr{}_{0.12}CuO{}_{4} under applied uniaxial pressure to demonstrate that the two density waves respond to the external tuning parameter in the same manner. Our result shows that suitable models for high-temperature superconductivity must equally account for charge and spin degrees of freedom via uniaxial charge-spin stripe fluctuations.

Quantum Hall phase in graphene engineered by interfacial charge coupling

The quantum Hall effect can be substantially affected by interfacial coupling between the host two-dimensional electron gases and the substrate, and has been predicted to give rise to exotic topological states. Yet the understanding of the underlying physics and the controllable engineering of this interaction remains challenging. Here we demonstrate the observation of an unusual quantum Hall effect, which differs markedly from that of the known picture, in graphene samples in contact with an antiferromagnetic insulator CrOCl equipped with dual gates. Two distinct quantum Hall phases are developed, with the Landau levels in monolayer graphene remaining intact at the conventional phase, but largely distorted for the interfacial-coupling phase. The latter quantum Hall phase is even present close to the absence of a magnetic field, with the consequential Landau quantization following a parabolic relation between the displacement field and the magnetic field. This characteristic prevails up to 100 K in a wide effective doping range from 0 to 1013 cm−2.

(Un)coupling the factors contributing to the interfacial activation of Streptomyces rimosus lipase: computational and spectrophotometric study

Streptomyces rimosus lipases (SrLip) present an enzyme class that catalyzes the hydrolysis of triacylglycerols producing fatty acids and glycerols. The abrupt increase in catalytic activity of SrLip when found at water-oil interface is assigned as interfacial activation (IA). Since the latter is a complex function of interface charge, chemical composition, as well as substrate orientation and concentration, the role of individual factors and their combinations that trigger IA remains rather elusive. The aim of this work is to unravel the contribution of particular factor in IA by examining SrLip activity toward p-nitrophenylpalmitate (p-NPP) as a substrate incorporated in three chemically different self-assembled aggregates: gum Arabic, sodium deoxycholate and liposomes made of 1,2-dioleyl-sn-glycero-3-phosphocholine (DOPC) lipids, and at two different pH values (pH = 6.8 and pH = 10.0). Spectrophotometric (UV/Vis) study revealed that SrLip catalyzes p-NPP hydrolysis when the substrate is embedded in sodium deoxycholate at both pH values, suggesting that the coupling of favorable interface charge and substrate orientation drives the interfacial activation. Moreover, especially in alkaline conditions (pH = 10.0), hydrolysis of the ester bond of the substrate incorporated in DOPC bilayers occurs when appropriate orientation, concentration and arrangement are accomplished. All experiments were conducted in parallel on an inactive mutant SrLipS10/A as a reference. The molecular-level details of particular interface and accompanied substrates examined by all-atom molecular dynamics simulations revealed that the availability of p-NPP at these three interfaces decreases in the following order: sodium-deoxycholate > DOPC > model gum Arabic.

Surface Charge and Nanoparticle Chromophore Coupling to Achieve Fast Exciton Quenching and Efficient Charge Separation in Photoacoustic Imaging (PAI) and Photothermal therapy (PTT) (Adv. Therap. 11/2022)

In article 2200168, Feng Liu, Yongming Zhang, and co-workers show that Y6 is a banana shaped molecule that can form strong intermolecular packing, which is manipulated by surface charge under restrained sizes, yielding new pi-pi stacking and fast exciton quenching. The temperature of the tumor area can rise to more than 70 degrees under NIR irradiation, which can effectively ablate the tumor. The developed strategy identifies a new avenue in biosensing and therapeutic applications.

Data For : Quantum Hall phase in graphene engineered by interfacial charge coupling

Data For : Quantum Hall phase in graphene engineered by interfacial charge coupling

Superhydrous aluminous silica phases as major water hosts in high-temperature lower mantle

Water transported by subducted oceanic plates changes mineral and rock properties at high pressures and temperatures, affecting the dynamics and evolution of the Earth's interior. Although geochemical observations imply that water should be stored in the lower mantle, the limited amounts of water incorporation in pyrolitic lower-mantle minerals suggest that water in the lower mantle may be stored in the basaltic fragments of subducted slabs. Here, we performed multianvil experiments to investigate the stability and water solubility of aluminous stishovite and CaCl2-structured silica, referred to as poststishovite, in the SiO2-Al2O3-H2O systems at 24 to 28 GPa and 1,000 to 2,000 °C, representing the pressure-temperature conditions of cold subducting slabs to hot upwelling plumes in the top lower mantle. The results indicate that both alumina and water contents in these silica minerals increase with increasing temperature under hydrous conditions due to the strong Al3+-H+ charge coupling substitution, resulting in the storage of water up to 1.1 wt %. The increase of water solubility in these hydrous aluminous silica phases at high temperatures is opposite of that of other nominally anhydrous minerals and of the stability of the hydrous minerals. This feature prevents the releasing of water from the subducting slabs and enhances the transport water into the deep lower mantle, allowing significant amounts of water storage in the high-temperature lower mantle and circulating water between the upper mantle and the lower mantle through subduction and plume upwelling. The shallower depths of midmantle seismic scatterers than expected from the pure SiO2 stishovite-poststishovite transition pressure support this scenario.

Flux coupling, not specificity, shapes the transport and phylogeny of SLC6 glycine transporters

ATB[Formula: see text] (SLC6A14) is a member of the amino acid transporter branch of the SLC6 family along with GlyT1 (SLC6A9) and GlyT2 (SLC6A5), two glycine-specific transporters coupled to 2:1 and 3:1 Na[Formula: see text]:Cl[Formula: see text], respectively. In contrast, ATB[Formula: see text] exhibits broad substrate specificity for all neutral and cationic amino acids, and its ionic coupling remains unsettled. Using the reversal potential slope method, we demonstrate a 3:1:1 Na[Formula: see text]:Cl[Formula: see text]:Gly stoichiometry for ATB[Formula: see text] that is consistent with its 2.1 e/Gly charge coupling. Like GlyT2, ATB[Formula: see text] behaves as a unidirectional transporter with virtually no glycine efflux at negative potentials after uptake, except by heteroexchange as remarkably shown by leucine activation of NMDARs in Xenopus oocytes coexpressing both membrane proteins. Analysis and computational modeling of the charge movement of ATB[Formula: see text] reveal a higher affinity for sodium in the absence of substrate than GlyT2 and a gating mechanism that locks Na[Formula: see text] into the apo-transporter at depolarized potentials. A 3:1 Na[Formula: see text]:Cl[Formula: see text] stoichiometry justifies the concentrative transport properties of ATB[Formula: see text] and explains its trophic role in tumor growth, while rationalizing its phylogenetic proximity to GlyT2 despite their extreme divergence in specificity.

Surface Charge and Nanoparticle Chromophore Coupling to Achieve Fast Exciton Quenching and Efficient Charge Separation in Photoacoustic Imaging (PAI) and Photothermal therapy (PTT)

AbstractAn organic semiconductor nanoparticle (OSN) with surface charge strategy is proposed, which displays excellent photothermal conversion performance. The donor–acceptor hybrid organic semiconductor Y6 is selected as a photothermal chromophore into nanoparticle by self‐assembly, which affords long wavelength absorption, sub‐bandgap emission, and high photon‐to‐thermal conversion. Y6 in OSN adopts closed packing comparing to that in single crystal. The surface charge in OSN causes super‐quenching of the photon excitons, which enhances the nonradiative transition to improve photothermal effect. Lower energy level electronic states are created, which breaks up the bandgap limit and leads to long wavelength emission over 1100 nm. Photothermal therapy and photoacoustic imaging are applied successfully, indicating the success of the new methodology in designing photothermal conversion materials.

Interface-Driven Multiferroicity in Cubic BaTiO3-SrTiO3 Nanocomposites.

Perovskite multiferroics have drawn significant attention in the development of next-generation multifunctional electronic devices. However, the majority of existing multiferroics exhibit ferroelectric and ferromagnetic orderings only at low temperatures. Although interface engineering in complex oxide thin films has triggered many exotic room-temperature functionalities, the desired coupling of charge, spin, orbital and lattice degrees of freedom often imposes stringent requirements on deposition conditions, layer thickness and crystal orientation, greatly hindering their cost-effective large-scale applications. Herein, we report an interface-driven multiferroicity in low-cost and environmentally friendly bulk polycrystalline material, namely cubic BaTiO3-SrTiO3 nanocomposites which were fabricated through a simple, high-throughput solid-state reaction route. Interface reconstruction in the nanocomposites can be readily controlled by the processing conditions. Coexistence of room-temperature ferromagnetism and ferroelectricity, accompanying a robust magnetoelectric coupling in the nanocomposites, was confirmed both experimentally and theoretically. Our study explores the 'hidden treasure at the interface' by creating a playground in bulk perovskite oxides, enabling a broad range of applications that are challenging with thin films, such as low-power-consumption large-volume memory and magneto-optic spatial light modulator.