Aqueous Zn metal batteries are considered as competitive candidates for next‐generation energy storage systems due to their excellent safety, low cost, and environmental friendliness. However, the ...inevitable dendrite growth, severe hydrogen evolution, surface passivation, and sluggish reaction kinetics of Zn metal anodes hinder the practical application of Zn metal batteries. Detailed summaries and prospects have been reported focusing on the research progress and challenges of Zn metal anodes, including electrolyte engineering, electrode structure design, and surface modification. However, the essential electrical mechanisms that significantly influence Zn2+ ions migration and deposition behaviors have not been reviewed yet. Herein, in this review, the regulation mechanisms of electrical‐related electrostatic repulsive/attractive interactions on Zn2+ ions migration, desolvation, and deposition behaviors are systematically discussed. Meanwhile, electric field regulation strategies to promote the Zn2+ ions diffusion and uniform Zn deposition are comprehensively reviewed, including enhancing and homogenizing electric field intensity inside the batteries and adding external magnetic/pressure/thermal field to couple with the electric field. Finally, future perspectives on the research directions of the electrical‐related strategies for building better Zn metal batteries in practical applications are offered.
Advanced approaches to prohibit dendrite growth, suppress side reactions, and promote reaction kinetics of Zn metal anodes are essential for practical Zn metal batteries. In this review, the effects of electrical‐related electrostatic interaction and electrical field regulation on the Zn2+ ions migration and deposition behavior in aqueous Zn metal batteries, with an emphasis on the challenges and prospects, are summarized.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
•The effect of electric field on the kerogen molecule was discussed.•The electrostatic interaction was analyzed through the ESP.•The reactivity of kerogen molecule was analyzed.
In this paper, the ...density functional theory (DFT) at a M06-2X/6–311 + G(d,p) level was employed to study the effect of electric field on the kerogen molecule--the main component of oil shale. Through reasonable assumptions, the kerogen molecular model was simplified, and different reaction channels were built according to the results obtained from the calculation through the Gaussian09 software package. Through the analysis of the reaction energy barriers in different reaction channels, the electric fields with different directions have different effects on a certain elementary reaction such as a kind of conversion of a hydrogen atom. By analyzing the electrostatic surface potentials (ESP) of van der Waals (vdW) surface, the main reason for the change of the reaction energy barrier was the electrostatic interaction which was influenced by the electric field. Moreover, the HOMO and LUMO density distribution for the molecule model illustrated that the reactivity of kerogen molecule can be improved by electric field. This paper provides an effective micro theoretical analysis method for the high voltage power frequency electrical heating method for oil shale pyrolysis, which provides atomic-level understanding of chemical reaction process beyond what laboratory experiments could accomplish.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
A silicon carbide shielded fin-shaped gate metal-oxide-semiconductor field effect transistor (SF-MOS) is proposed in this letter, which utilizes a well-grounded p-region to shield the fin-shaped ...trench gate. Numerical simulations by Sentaurus TCAD are carried out to study the performance of SF-MOS, and comparisons with conventional trench MOSFET and the state-of-the-art double-trench MOSFET are presented. The maximum electric field in gate oxide of the SF-MOS is effectively lowered to below 3 MV/cm, which is a widely accepted criterion for long-term gate oxide reliability. Furthermore, with the shielding effects, the gate-to-drain charge of the SF-MOS is significantly reduced, leading to lower switching loss.
Within the framework of effective mass approximation and with the use of finite element method, we calculate the energy states of an electron in a double toroidal quantum ring with a Hopf link ...structure. The study includes the influence of externally applied static electric and magnetic fields, and considers different geometric combinations of radii and link positions. We have found that geometric manipulations have significant impact on the energy values and the distribution of electronic probability densities in either one or both linked rings. Similar effects can be achieved with the application of the electromagnetic probes.
•Novel Hopf link quantum ring system has been modeled in finite potential barriers.•Electrical and magnetic fields tune the density probability of one confined electron.•Some geometric configurations allow overcoming the isolation of potential barriers.•Energy oscillations under magnetic field are only evident for excited states.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
An unexpected mechanistic switch as well as a change of the product distribution in the thermal gas‐phase activation of methane have been identified when diatomic ZnO.+ is ligated with acetonitrile. ...Theoretical studies suggest that a strong metal–carbon attraction in the pristine ZnO.+ species plays an important role in the rebound of the incipient CH3. radical to the metal center, thus permitting the competitive generation of CH3., OH., and CH3OH. This interaction is drastically weakened by a single CH3CN ligand. As a result, upon ligation the proton‐coupled single electron transfer that prevails for ZnO.+/CH4 switches to the classical hydrogen‐atom‐transfer process, thus giving rise to the exclusive expulsion of CH3.. This ligand effect can be modeled quite well by an oriented external electric field of a negative point charge.
A simple ligand turns off two of the three channels operative in the ZnO.+/CH4 couple. As a result, only hydrogen‐atom ion occurs for the (CH3CN)ZnO.+/CH4 system. This remarkable ligand effect can be modeled well by an oriented external electric field. PCSET: proton‐coupled single‐electron transfer; OEEF: oriented external electric field; HAT: hydrogen‐atom transfer.
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A heterojunction Al2O3/BiOBr composite photocatalyst, characterized by an S-scheme structure and enriched with oxygen vacancies, was synthesized through a solvothermal reaction coupled with an in ...situ growth approach. Oxygen vacancies on the catalyst surface, enhanced by the robust coupling between Al2O3 and BiOBr, were corroborated by X-ray photoelectron spectroscopy (XPS) and electron paramagnetic resonance (EPR). Techniques such as UV–vis diffuse reflectance spectroscopy (DRS), UV photoelectron spectroscopy (UPS), Mott–Schottky characterization, and experimental radical trapping experiments collectively validated the pathways for migrating photogenerated carriers. The interplay between the surface oxygen vacancies and the S-scheme Al2O3/BiOBr heterojunction, which possesses potent redox capabilities, significantly improved the photocatalytic degradation. This enhancement was particularly evident in the outstanding visible photocatalytic degradation performance against rhodamine B (RhB), methyl orange (MO), and basic fuchsin (BF). The synthesized composite photocatalysts demonstrated 92% retention of degradation efficiency after five recycling cycles, indicating their considerable stability.
•A solvothermal method is proposed to prepare Al2O3/BiOBr catalyst, showing high efficiency in degrading dyes.•The unique flower-like structure and S-scheme heterojunction with built-in electric field boost carrier migration rate.•Oxygen-rich vacancies provide reaction sites to enhance the catalytic ability of the photocatalyst
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
In this letter, an internal electric field shielding layer for high voltage winding of medium voltage high frequency transformer used in a modular cascaded medium voltage solid state transformer is ...proposed. Without breaking the litz wire insulation layer, the high electric field is effectively shielded by a semiconducting layer and an unclosed copper foil spiral, which are electrically connected together. Not only the electric field in the main wall insulation is uniformed but also the peak value of the internal field is greatly reduced, which will help to achieve lower partial discharge and higher insulation reliability. With this structure, the difficulties of pouring process and electric field estimation for the litz wire winding are both avoid. Finally, a no partial discharge 100 kW medium voltage high frequency transformer prototype with 75 kV base insulation level is built and verified with the insulation tests.
Abstract
Electrocoalescence has long been known for the separation of a water‐in‐oil emulsion. An associated challenge with electrocoalescers is the undesired noncoalescence and consequently chain ...formation of aqueous phase droplets. This leads to low separation efficiency and damage of electrical equipment. Recently Hasib et al. proposed an electric field modulated scheme that showed significant improvement in dehydration of water‐in‐oil emulsions. They investigated the range of modulation parameters when the scheme is most effective. The fundamental process in electrostatic dehydration of an emulsion is the interaction between a pair of water droplets. In the present study, two suspended aqueous drops in insulated oil experiments are compared for their behavior under unmodulated and modulated electric fields. Further, a model is developed and the experimental behavior under unmodulated and modulated electric fields is compared with numerical solutions. The model predicts the experimental observations accurately by balancing electrostatic, electrophoresis, dipolar, and resisting viscous drag forces, ignoring the end (bridge) effect during the contact. The study shows that the increase in the rate of dehydration of a water‐in‐oil emulsion under modulated electric fields with an increase in duty ratio and its near independence on the modulation time period can be explained by the two‐drop studies. However, several other processes such as multidrop interactions as well as scavenging of fine droplets by charged droplets created as intermediates in the interaction of two droplets cannot be explained by the two‐drop studies.
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BFBNIB, FZAB, GIS, IJS, KILJ, NLZOH, NUK, OILJ, SBCE, SBMB, UL, UM, UPUK
•Scale is inhibited by using an alternating electric field.•Developed an inhibition scale device suitable for industrial site.•The continuous scale inhibition experiment was conducted for 920 hours.
...The present study introduces an alternating electric field device that can effectively inhibit the growth of scale on industrial heat exchangers. The 5–70 V voltage and alternating electric field (AEF) of 80–300 kHz frequency are transferred by the device in water where they can inhibit scale formation on tube walls by changing the precipitation mode of mineral ions. After the alternating electric field device is used, the scale thickness on the heat exchange surface becomes significantly thinner, and the maximum fouling resistance decreases by 58% (from 8.54 10−4m2K/W to 3.58 10−4m2K/W). Scanning electron microscopy (SEM) results show that after the use of the alternating electric field device, the scale on the heat exchange surface changed from dense crystals with irregular, sharp shape to loose crystals with spherical shape, and X-ray diffraction (XRD) analysis showed that most crystals changed from calcite to aragonite. X-ray energy dispersion spectroscopy (EDS) analysis showed that the weight percentage of Fe in the scale decreased by 9.81%. This shows that scale and corrosion on the heat exchange surface can be effectively improved under the action of an electric field.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
•Transport mechanism at different Pe is analyzed.•Heat transfer rate decreases with deformation rate at moderate Pe.•Oblate droplet has the best heat transfer performance when convection ...dominates.•Direction of flow circulation has little impact on the heat/mass transfer.
Transient heat/mass transfer to a deformed droplet suspended in the ambient fluid in the presence of a steady electric field is investigated. By considering an internal problem, a numerical model is established to incorporate the flow field and heat transfer in a two-dimensional axisymmetric framework with the phase field method to track the deformed interface. The model is validated, and an excellent agreement is achieved. For a spherical droplet, as Peclet number (Pe) increases from 10 to 1000, the number of the region with closed contours of temperature increases from 1 to 4 (with 2 for Pe=100), which may explain the increase of Nu at this range of Pe. When Pe further increases to infinite, the transport is limited by the rate of cross-streamline conduction. At low Pe, the transport process is dominated by the conduction, and the heat transfer rate is always enhanced for a deformed droplet with smaller conduction length scale and greater surface area. However, at moderate Pe, the heat transfer rate is suppressed by the deformation rate (D). The analysis on the transport mechanism suggests that the conduction and convection play the comparable roles in affecting the transport process, and the deformation will weaken both the conduction near the surface and the convection in the droplet interior. The oblate droplet is less suppressed by the deformation rate compared with the prolate droplet. When Pe is large (e.g., Pe=1000), the heat transfer rate of oblate droplet will increase with the D. However, for prolate droplets, the overall transfer rate presents a non-monotonous trend with D. The transient behaviors of the heat transfer at high Pe and the length scale of the cross-streamline conduction for different deformed droplets are discussed. Furthermore, it is inferred that the oblate droplet has the advantage in driving more fluid into the droplet interior when the convection dominates.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
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