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The paper deals with minimum energy problems in the presence of external fields on a locally compact space X with respect to a function kernel κ satisfying the energy and consistency principles. For quite a general (not necessarily lower semicontinuous) external field f, we establish sufficient and/or necessary conditions for the existence of λ A , f minimizing the Gauss functional ∫ κ (x , y) d (μ ⊗ μ) (x , y) + 2 ∫ f d μ over all positive Radon measures μ with μ (X) = 1 , concentrated on quite a general (not necessarily closed or bounded) set A ⊂ X , thereby giving an answer to a question raised by M. Ohtsuka (J. Sci. Hiroshima Univ., 1961). Such results are specified for the Riesz kernels | x - y | α - n , 0 < α < n , on R n , n ⩾ 2 , and are illustrated by some examples. Furthermore, we provide various alternative characterizations of the minimizer λ A , f , and as a by-product we prove the continuity of both λ A , f and the modified Robin constant under the exhaustion of A by compact K ⊂ A . Along with the advantages of using perfect kernels, the analysis performed is substantially based on the author's recent theory of inner balayage on locally compact spaces (Potential Anal., 2022). The results obtained do hold and are new for many interesting kernels in classical and modern potential theory. [ABSTRACT FROM AUTHOR]

Conventional CO2 capture technologies often focus on the simple capture process, while the absorption and high-value utilization of carbon capture products have profound significance, especially when combined with the utilization of biomass energy. Novel ammonia-based CO2 capture coupled with selective silicon dissolution was proposed with process regulation of external fields (i.e. magnetic field, microwave field, ultrasound field) used to prepare nano silica. The results show that the magnetic field plays a dual role of “vibration stirring” and adding energy (11.2 J/mol) on the formation and dispersion of nano silica. The specific surface area of nano-silica is increased from 140.24 m2/g to 280 m2/g by microwave field (250 W), and its “internal heating” promotes the formation of crystal nuclei. The ultrasonic field reduces the primary particle size of nano-silica by 3.17 nm, and inhibits the particle growth through cavitation and mechanical vibration. It would provide parameter support and optimization guidance for the low-cost high-quality nano silica for high-value utilization of ammonia-based CO2 capture products.

Electrocatalytic technology provides a promising approach for energy storage, conversion, and utilization. The design and modification of electrocatalysts have been widely applied to improve the performance of electrocatalytic reactions, but bottlenecks can be entered that make it hard to make dramatic progress. The achievement of high‐performance electrocatalysis requires a continuous effort in advancing the new techniques. The introduction of external fields is an attractive approach to improve the mass transfer and change the reaction kinetics, which can remarkably enhance the electrocatalytic performance. This review describes the recent developments in the application of various external fields, including light, magnetic fields, elastic strain, external pressure, and gravity, to boost electrocatalytic reactions (e.g., water splitting, alcohols oxidation, CO2 reduction, and N2 reduction). The relevant mechanisms of external fields to boost charge transport, mass transfer, and the adsorption of reactants are highlighted. Finally, the remaining challenges and future opportunities for coupling external fields with electrocatalysis are discussed. [ABSTRACT FROM AUTHOR]

Abstract The chief culprit impeding the commercialization of lithium–sulfur (Li–S) batteries is the parasitic shuttle effect and restricted redox kinetics of lithium polysulfides (LiPSs). To circumvent these key stumbling blocks, incorporating electrocatalysts with rational electronic structure modulation into sulfur cathode plays a decisive role in vitalizing the higher electrocatalytic activity to promote sulfur utilization efficiency. Breaking the stereotype of contemporary electrocatalyst design kept on pretreatment, field‐assisted electrocatalysts offer strategic advantages in dynamically controllable electrochemical reactions that might be thorny to regulate in conventional electrochemical processes. However, the highly interdisciplinary field‐assisted electrochemistry puzzles researchers for a fundamental understanding of the ambiguous correlations among electronic structure, surface adsorption properties, and catalytic performance. In this review, the mechanisms, functionality explorations, and advantages of field‐assisted electrocatalysts including electric, magnetic, light, thermal, and strain fields in Li–S batteries have been summarized. By demonstrating pioneering work for customized geometric configuration, energy band engineering, and optimal microenvironment arrangement in response to decreased activation energy and enriched reactant concentration for accelerated sulfur redox kinetics, cutting‐edge insights into the holistic periscope of charge‐spin‐orbital‐lattice interplay between LiPSs and electrocatalysts are scrutinized, which aspires to advance the comprehensive understanding of the complex electrochemistry of Li–S batteries. Finally, future perspectives are provided to inspire innovations capable of defeating existing restrictions.

Dibromomethane decomposes into ozone destroying bromine free radicals under sunlight radiation, which seriously endangers the natural environment and human health. It is necessary to study the degradation of Dibromomethane. The physical properties of Dibromomethane including total energy, bond length, electric dipole moment, energy level, energy gap, infrared spectrum under different external electric fields（0 ～ 0.025 a. u.） are studied by using density functional theory at the B3 LYP/6-311 G（d, p） basis set level. The effect of external electric field on molecular excited states is studied by using time-dependent density functional theory at the same basis set level. The potential energy curves of two C-Br bonds under external electric field are scanned separately, and it is found that when the external electric field intensities are 0.025 a.u. and 0.04 a.u., both the C-Br bonds are broken in turn and gradually dissociated. The results provide an important reference for the electric field degradation of Dibromomethane and hence for environmental protection. [ABSTRACT FROM AUTHOR]

In this paper, we investigate Riesz energy problems on unbounded conductors in R d in the presence of general external fields Q, not necessarily satisfying the growth condition Q (x) → + ∞ as | x | → + ∞ assumed in several previous studies. We provide sufficient conditions on Q for the existence of an equilibrium measure and the compactness of its support. Particular attention is paid to the case of the hyperplanar conductor R d , embedded in R d + 1 , when the external field is created by the potential of a signed measure ν supported outside of R d . Simple cases where ν is a discrete measure are analyzed in detail. New theoretic results for Riesz potentials, in particular an extension of a classical theorem by de La Vallée Poussin, are established. These results are of independent interest. [ABSTRACT FROM AUTHOR]

• The polarization built-in electric fields (BIEFs) and interface BIEFs were defined. • The formation process of various types of interface BIEFs was summarized. • The mechanism of self-healing BIEFs coupled with external fields were proposed. • The analysis methods of BIEFs and their photocatalytic applications were summarized. The applications of photocatalysis in environmental remediation and energy generation are severely constrained due to the rapid recombination of photogenerated carriers within photocatalysts. Built-in electric fields (BIEFs) have shown the potential to address this challenge, while few reviews on BIEFs are available focusing on features of heterojunction and self-healing. This paper provides such a critical review on the state of the art of BIEFs, especially fills the gap in the review of novel self-healing BIEFs. Firstly, the definitions of polarization and interface BIEFs were clearly defined, and the formation mechanisms were elucidated. Secondly, the synergistic effect of the external fields and BIEFs was reviewed and discussed, and the design principles and mechanisms of self-healing BIEFs were commented for the first time. Thirdly, the analysis methods from different perspectives were summarized, and the driving mechanisms of BIEFs in different photocatalytic applications were elaborated. At last, the challenges and future prospects of BIEFs were discussed in depth. This review could provide guidance in the in-depth research and applications of BIEFs in photocatalysis. [ABSTRACT FROM AUTHOR]

The scarcity of energy and environmental issues caused by fossil fuels seriously affect human development, making it imperative to develop new green energy storage and conversion technologies. Water splitting and rechargeable metal-air batteries have broad application prospects, but their development is limited by the slow rate of the Oxygen evolution reaction (OER). Introducing catalysts can accelerate OER and reduce the overpotential required for the reaction. While most work on catalyst modification focuses on the catalyst itself, some works have achieved this through the assistance of external fields, such as magnetic, electric, and photo fields. The application of thermal fields can be traced back to earlier and has a wider range of applications. However, when it comes to the role of thermal, it is generally believed that thermal change the organization or phase of materials during the synthesis process, as seen in the typical heat treatment of steel. It is also commonly believed that the higher the temperature, the more effective molecular collisions, which accelerates the reaction rate. While this is correct, it is not comprehensive. This review combines the latest work on the application of thermal energy to OER, providing a comprehensive analysis of the contribution of thermal energy to accelerating OER, including its role in the synthesis process, the photothermal effect, and other aspects. It specifically discusses the impact of temperature-induced bubbles on OER rates and whether the continuous increase in temperature will lead to an unrestricted increase in reaction rates. Additionally, the review provides some considerations for the application of thermal energy to OER and prospects for the development of this field. [Display omitted] [ABSTRACT FROM AUTHOR]

This paper is focused on characterization of magnetic fluids (MFs) and experimental investigation of interfacial structural changes in transformer oil-based magnetic fluids (TOMFs) under the influence of electric field. Recently, such nanodielectric fluids have been proposed to be used as transformer liquid insulation as the addition of particles seeks to improve the dielectric and thermal properties of the base liquids. Ferrofluids typically respond to electric and magnetic fields and can be easy manipulated by such external fields. By mean of neutron reflectometry (NR), we show impact of the electric field intensity on magnetic nanoparticle aggregates in a dilute (1.8 vol %.) classical ferrofluid.

This paper is devoted to the studies of the specific features of the simulation of the particle diffusion processes in space – periodic potentials using Langevin equations. Different methods used for the presetting of initial conditions and their effect on the obtained solutions have been analyzed. It is shown that the system is nonequilibrium for all the methods of the presetting of initial conditions during a certain time interval of ttrm. This interval is increased as 1/γ with a decrease in the friction coefficient. A reasonable description of the transient processes of particle transport and diffusion requires a preliminary system thermalization procedure. A new method of the presetting of initial conditions that provides the most accurate description of equilibrium system has been suggested. It consists in the generation of the initial particle coordinates and velocities that correspond to the equilibrium distribution of harmonic oscillators with a specified temperature. The use of such initial conditions enables the computations with a good accuracy using no thermalization procedure at T < 0.1. The classic method of the determination of diffusion coefficients D as a limit limt→ꝏ (σ2/t) has been analyzed. It was shown that the use of it for computer-aided calculations is limited by the restricted computational time. It results in that the computation of D under certain conditions becomes impossible. A new method was suggested for the determination of the diffusion coefficient using the linear approximation of the dependence of dispersion on time. This approximation can only be possible after the kinetic temperature attains its stationary value. The suggested method requires several orders of magnitude less time in comparison to the classic method. As a result, it enables the computation of the diffusion coefficient even in the cases of total previous failure. The obtained data are of great importance for correct simulation computations of diffusion processes and for the appropriate physical interpretations of obtained data.

CO2 capture and conversion has been prospected as an auspicious technology to simultaneously tackle the rise in global CO2 emission and produce value‐added fuels with the goal of accomplishing carbon neutrality. A sustainable route to achieve this is via the utilization of solar energy, thereby harnessing the abundant and nonexhaustive resource to shift our reliance away from rapidly depleting fossil fuels. Graphitic carbon nitride (g‐C3N4) and its allotrope have earned its rank as a fascinating metal‐free photocatalyst due to its superior stability, high surface‐area‐to‐volume ratio, and tunable surface engineering. By leveraging these properties, robust carbon nitride‐based nanostructures are engineered for photocatalytic CO2 conversion to energy‐rich C1C2 product, which is indispensable in the chemical industry. Thus, this review presents the latest panorama of experimental and computational research on tuning the local electronic, surface chemical coordination environment, charge dynamics and optical properties of low‐dimensional carbon nitride and its allotropes toward highly selective and efficient CO2 photoconversion. To name a few, structural engineering, point‐defect engineering, heterojunction construction, and cocatalyst loading. To advance this frontier, critical insights are elucidated to establish the structure‐performance relationship and unravel primary factors dictating the selectivity of C1C2 molecules from CO2 reduction. External‐field assisted photocatalysis such as with electric (photoelectro‐) and heat (photothermal) is discussed to uncover the synergistic contributions that drive the development in photochemistry. Last, future challenges and prospects are outlined for the potential application of solar‐driven CO2 conversion, along with the scale‐up strategy from the economic viewpoint toward the rational development of high‐efficiency carbon nitride catalysts. [ABSTRACT FROM AUTHOR]

This paper is focused on characterization of magnetic fluids (MFs) and experimental investigation of interfacial structural changes in transformer oil-based magnetic fluids (TOMFs) under the influence of electric field. Recently, such nanodielectric fluids have been proposed to be used as transformer liquid insulation as the addition of particles seeks to improve the dielectric and thermal properties of the base liquids. Ferrofluids typically respond to electric and magnetic fields and can be easy manipulated by such external fields. By mean of neutron reflectometry (NR), we show impact of the electric field intensity on magnetic nanoparticle aggregates in a dilute (1.8 vol %.) classical ferrofluid. [ABSTRACT FROM AUTHOR]

Abstract CO2 capture and conversion has been prospected as an auspicious technology to simultaneously tackle the rise in global CO2 emission and produce value‐added fuels with the goal of accomplishing carbon neutrality. A sustainable route to achieve this is via the utilization of solar energy, thereby harnessing the abundant and nonexhaustive resource to shift our reliance away from rapidly depleting fossil fuels. Graphitic carbon nitride (g‐C3N4) and its allotrope have earned its rank as a fascinating metal‐free photocatalyst due to its superior stability, high surface‐area‐to‐volume ratio, and tunable surface engineering. By leveraging these properties, robust carbon nitride‐based nanostructures are engineered for photocatalytic CO2 conversion to energy‐rich C1C2 product, which is indispensable in the chemical industry. Thus, this review presents the latest panorama of experimental and computational research on tuning the local electronic, surface chemical coordination environment, charge dynamics and optical properties of low‐dimensional carbon nitride and its allotropes toward highly selective and efficient CO2 photoconversion. To name a few, structural engineering, point‐defect engineering, heterojunction construction, and cocatalyst loading. To advance this frontier, critical insights are elucidated to establish the structure‐performance relationship and unravel primary factors dictating the selectivity of C1C2 molecules from CO2 reduction. External‐field assisted photocatalysis such as with electric (photoelectro‐) and heat (photothermal) is discussed to uncover the synergistic contributions that drive the development in photochemistry. Last, future challenges and prospects are outlined for the potential application of solar‐driven CO2 conversion, along with the scale‐up strategy from the economic viewpoint toward the rational development of high‐efficiency carbon nitride catalysts.

The dependence of the magnetization and magnetic susceptibility of donor impurity in parabolic GaAs (Gallium Arsenide) quantum dot has been investigated, at finite temperature under the influence of external tilted electric and magnetic fields. Based on the effective mass approximation, the Hamiltonian of an electron confined in a parabolic quantum dot in the presence of donor impurity which is presented in electric and magnetic fields has been solved by employing the numerical diagonalization method of the Hamiltonian matrix. All the energy matrix elements have been obtained in analytical form. We have shown the variations of the statistical energy and binding energy of donor impurity with the electric and magnetic field strengths and tilt electric field angle. The computed results show that the electrical field can tune the magnetic properties of the QD GaAs medium by flipping the sign of its magnetic susceptibility from diamagnetic (χ 0).

The efficient conversion of solar energy by means of photocatalysis shows huge potential to relieve the ongoing energy crisis and increasing environmental pollution. However, unsatisfactory conversion efficiency still hinders its practical application. The introduction of external fields can remarkably enhance the photocatalytic performance of semiconductors from the inside out. This review focuses on recent advances in the application of diverse external fields, including microwaves, mechanical stress, temperature gradient, electric field, magnetic field, and coupled fields, to boost photocatalytic reactions, for applications in, for example, contaminant degradation, water splitting, CO2 reduction, and bacterial inactivation. The relevant reinforcement mechanisms of photoabsorption, the transport and separation of photoinduced charges, and adsorption of reagents by the external fields are highlighted. Finally, the challenges and outlook for the development of external‐field‐enhanced photocatalysis are presented. [ABSTRACT FROM AUTHOR]

We investigate theoretically the total refractive index changes (TRICs) and the total absorption coefficients (TACs) of two‐electron Gaussian quantum dot (TEGQD) including Gaussian potential confinement generated by GaAs/GaAlAs heterostructure, embedded in Debye and quantum plasma environments modeled by the more general exponential cosine screened Coulomb (MGECSC) potential, under the influence of the external electric and magnetic field. The wave equation is solved within the effective mass approach framework by using Runge–Kutta–Fehlberg method in order to obtain the subband spectra and the electronic wave functions of TEGQD. Nonlinear optical response of TEGQD is obtained through the compact‐density‐matrix formalism within the iterative method. The effects of both Debye and quantum plasma environments in the strong and weak regimes of the external fields are considered and compared throughout the study. The potents of the external electric field, the external magnetic field, the quantum dot width, the barrier height, and the plasma screening on TRICs and TACs resonant frequencies and amplitudes are analyzed. In addition to these analyses, the alternatives to each parameter effects of the model are also elucidated. TRICs and TACs analyze are carried out in a plasma‐free environment, and thus the function of environments with plasma compared to that without plasma is better explained. Thanks to all these reviews, it is elucidated how to and at what ranges perform in terms of the incident photon energy of TEGQD's optimum for TRICs and TACs characters by using plasma, and in which cases it will be an alternative to the external field and geometrical encompassing. [ABSTRACT FROM AUTHOR]

In this paper, we investigate discrete logarithmic energy problems in the unit circle. We study the equilibrium configuration of n electrons and n-1 pairs of external protons of charge +1/2. It is shown that all the critical points of the discrete logarithmic energy are global minima, and they are the solutions of certain equations involving Blaschke products. As a nontrivial application, we refine a recent result of Simanek; namely, we prove that any configuration of n electrons in the unit circle is in stable equilibrium (that is, they are not just critical points but are of minimal energy) with respect to an external field generated by n-1 pairs of protons. [ABSTRACT FROM AUTHOR]

We proceed further with the study of minimum weak Riesz energy problems for condensers with touching plates, initiated jointly with Fuglede (Potential Anal 51:197–217, 2019). Having now added to the analysis constraint and external source of energy, we obtain a Gauss type problem, but with weak energy involved. We establish sufficient and/or necessary conditions for the existence of solutions to the problem and describe their potentials. Treating the solution as a function of the condenser and the constraint, we prove its continuity relative to the vague topology and the topologies determined by the weak and standard energy norms. We show that the criteria for the solvability thus obtained fail in general once the problem is reformulated in the setting of standard energy, thereby justifying an advantage of weak energy when dealing with condensers with touching plates. [ABSTRACT FROM AUTHOR]

Micro/nanomotors are able to convert energy in different forms into propulsion and movement with predesigned directions and velocities, enabling them to be self‐propelled carriers and vehicles for the delivery of active pharmaceutical ingredients and other biomedical cargos to the target sites such as tumors. However, the inadequate energy and noncontrollable moving directions remain the grand challenges for their promising applications. Recently, an increasing attention has been paid to these issues and numerous reported researches have focused to design and develop more efficient and precisely controllable micro/nanomotors with different methods. This review aims to summarize those studies and to introduce newly developed micro/nanomotors including synthetic micro/nanomotors and biohybrid motors, discussing the control mechanisms as well as advantages and limitations thereof. Conclusions and future perspectives are also provided in brief.

We develop further the concept of weak α-Riesz energy with α ∈ (0,2] of Radon measures μ on ℝ n , n ≥ 3 , introduced in our preceding study and defined by ∫ (κ α / 2 μ) 2 d m , m denoting the Lebesgue measure on ℝ n . Here κα/2μ is the potential of μ relative to the α/2-Riesz kernel |x − y|α/2−n. This concept extends that of standard α-Riesz energy, and for μ with κα/2μ ∈ L2(m) it coincides with that of Deny-Schwartz energy defined with the aid of the Fourier transform. We investigate minimum weak α-Riesz energy problems with external fields in both the unconstrained and constrained settings for generalized condensers (A1,A2) such that the closures of A1 and A2 in ℝ n are allowed to intersect one another. (Such problems with the standard α-Riesz energy in place of the weak one would be unsolvable, which justifies the need for the concept of weak energy when dealing with condenser problems.) We obtain sufficient and/or necessary conditions for the existence of minimizers, provide descriptions of their supports and potentials, and single out their characteristic properties. To this end we have discovered an intimate relation between minimum weak α-Riesz energy problems over signed measures associated with (A1,A2) and minimum α-Green energy problems over positive measures carried by A1. Crucial for our analysis of the latter problems is the perfectness of the α-Green kernel, established in our recent paper. As an application of the results obtained, we describe the support of the α-Green equilibrium measure. [ABSTRACT FROM AUTHOR]

In the present article, we study the energy eigenvalues and wavefuntions of the spinless particles in the existance of space-dependent electric and magnetic fields. The investigation is performed for two different orientations of the external fields by solving the Schrödinger and Klein-Gordon equations via Asymptotic Iteration Method (AIM). The obtained results are discussed numerically for first few quantum levels to understand the relativistic contributions by comparing the energy eigenvalues of Schrödinger and Klein-Gordon equations. By considering the quantum conditions for the resulting equations in the case of parallel and orthogonal orientations of the fields, we obtained the plots for the energy levels. [ABSTRACT FROM AUTHOR]

Micro/nanomotors are able to convert energy in different forms into propulsion and movement with predesigned directions and velocities, enabling them to be self‐propelled carriers and vehicles for the delivery of active pharmaceutical ingredients and other biomedical cargos to the target sites such as tumors. However, the inadequate energy and noncontrollable moving directions remain the grand challenges for their promising applications. Recently, an increasing attention has been paid to these issues and numerous reported researches have focused to design and develop more efficient and precisely controllable micro/nanomotors with different methods. This review aims to summarize those studies and to introduce newly developed micro/nanomotors including synthetic micro/nanomotors and biohybrid motors, discussing the control mechanisms as well as advantages and limitations thereof. Conclusions and future perspectives are also provided in brief. [ABSTRACT FROM AUTHOR]

Nano‐ and micromotors are fascinating objects that can navigate in complex fluidic environments. Their active motion can be triggered by external power sources or they can exhibit self‐propulsion using fuel extracted from their surroundings. The research field is rapidly evolving and has produced nano/micromotors of different geometrical designs, exploiting a variety of mechanisms of locomotion, being capable of achieving remarkable speeds in diverse environments ranging from simple aqueous solutions to complex media including cell cultures or animal tissue. This review aims to provide an overview of the recent developments with focus on predominantly experimental demonstrations of the various motor designs developed in the past 24 months. First, externally driven motors are discussed followed by considering fuel‐driven approaches. Finally, a short future perspective is provided. [ABSTRACT FROM AUTHOR]

We study minimum energy problems relative to the α -Riesz kernel | x - y | α - n , α ∈ (0 , 2 ] , over signed Radon measures μ on R n , n ⩾ 3 , associated with a generalized condenser (A 1 , A 2) , where A 1 is a relatively closed subset of a domain D and A 2 = R n \ D . We show that although A 2 ∩ Cl R n A 1 may have nonzero capacity, this minimum energy problem is uniquely solvable (even in the presence of an external field) if we restrict ourselves to μ with μ + ⩽ ξ , where a constraint ξ is properly chosen. We establish the sharpness of the sufficient conditions on the solvability thus obtained, provide descriptions of the weighted α -Riesz potentials of the solutions, single out their characteristic properties, and analyze their supports. The approach developed is mainly based on the establishment of an intimate relationship between the constrained minimum α -Riesz energy problem over signed measures associated with (A 1 , A 2) and the constrained minimum α -Green energy problem over positive measures carried by A 1 . The results are illustrated by examples. [ABSTRACT FROM AUTHOR]

[Display omitted] • Review of unconventional heat and external field-assisted employed for DRM. • Induction/microwave efficiently heat and promote reactant activation. • External field-assists effectively lower reaction temperature and promote DRM. • Rational catalyst design is crucial to effective use of these external energies. The dry reforming of methane (DRM) reaction is a process that converting CH 4 and CO 2 into syngas (H 2 and CO), serving as a promising pathway for industrial raw materials production and greenhouse effect mitigation. However, challenges arise in high-temperature thermal catalysis, such as carbon deposition, catalyst inactivation, and high energy consumption. Introducing exogenous energy and fields offers potential for a low-energy consumed and efficient DRM reaction process. Unlike conventional thermocatalytic mechanisms, the temperature and activation energy required to drive DRM can be reduced, and the thermodynamic constraints can be broken down. This review provides a comprehensive overview of highly efficient heating techniques, including induction heating and microwave heating, as well as external fields such as photo-, dielectric barrier discharge-, and electric field- assisted DRM. The aim is to give a comprehensive understanding of lowering energy consumption and improving activity. Mechanism and characteristics of each technique on catalytic reforming reaction are introduced, while potential challenges and research directions proposed for these approaches are proposed. [ABSTRACT FROM AUTHOR]

This comprehensive study utilizes the full tight-binding model and Green's function approach, employing the linear response theory, to investigate the electronic and thermal conductance of penta-graphene (PG) under various external parameters such as bias voltage, magnetic field, and doping. The results reveal that these parameters significantly enhance the thermoelectric properties of PG through modifications in its band structure and increased charge carrier density. By applying electric and magnetic fields, the wide band gap of PG, can be substantially reduced, with the magnetic field inducing subband splitting and modifying the band edges. The thermal properties of PG are initially negligible below 1500 K in the absence of external fields, but their magnitude increases remarkably by external fields, with the magnetic field exhibiting a more pronounced effect than the electric field. Interestingly, the chemical potential exhibits a surprising influence on the temperature dependence of PG's thermal properties, surpassing even the impact of the magnetic field at higher temperatures. The Lorenz number of PG complies with the Wiedemann-Franz law, remaining constant at low temperatures and reaching a peak value at higher temperatures and external fields alters this behavior by reducing the constant region and shifting the peak to lower temperatures. Moreover, the presence of electron-hole impurities in PG leads to peaks in the power factor (PF) and figure of merit (ZT), with the electric and magnetic fields causing these peaks to shift towards lower impurity concentrations. These findings highlight the potential of PG for various device applications and open up new avenues for further research and development in this promising field. • Bias voltage and magnetic fields can significantly reduce the wide band gap of (PG). • The thermal properties of PG are more sensitive to magnetic fields than electric fields. • The chemical potential has a surprisingly strong influence on the temperature dependence of PG's thermal properties. • The Lorenz number of PG obeys the Wiedemann-Franz law, exhibiting a peak at higher temperatures. • Electron-hole impurities in PG lead to peaks in the PF and ZT, depending on the impurity concentrations. [ABSTRACT FROM AUTHOR]

Particle-polymer dispersions are ubiquitous in additive manufacturing (AM), where they are used as inks to create composite materials with applications to wearable sensors, energy storage materials, and actuation elements. It has been observed that directional alignment of the particle phase in the polymer dispersion can imbue the resulting composite material with enhanced mechanical, electrical, thermal or optical properties. Thus, external field-driven particle alignment during the AM process is one approach to tailoring the properties of composites for end-use applications. This review article provides an overview of externally directed field mechanisms (e.g., electric, magnetic, and acoustic) that are used for particle alignment. Illustrative examples from the AM literature show how these mechanisms are used to create structured composites with unique properties that can only be achieved through alignment. This article closes with a discussion of how particle distribution (i.e., microstructure) affects mechanical properties. A fundamental description of particle phase transport in polymers could lead to the development of AM process control for particle-polymer composite fabrication. This would ultimately create opportunities to explore the fundamental impact that alignment has on particle-polymer composite properties, which opens up the possibility of tailoring these materials for specific applications.

The effects of different external fields on the microstructures and properties of twin-roll casting (TRC) 2099 Al Li alloy sheets as well as their mechanism of action were investigated in detail. The serious central segregation of 2099 Al Li alloy cast-rolled sheets is due to the unique properties of TRC process such as the high cooling intensity and the wide solidification range of 2099 alloy. The degree of central segregation and dendritic segregation of cast-rolled sheets abates significantly as well as the number of non-equilibrium eutectic phase decreases dramatically under the action of steady static magnetic field, pulse electric field and electromagnetic oscillation field during the TRC process. Especially, the improvement effect of electromagnetic oscillation field is the most remarkable. The electromagnetic stirring force to the mushy zone caused by electromagnetic oscillation field in TRC can not only reduce the temperature gradient and concentration gradient of solute ahead of the crystallizing front but also effectively increase the solute mixing capacity and solid solubility, which reduces the hardness difference along thickness direction and further improves the mechanical properties of the 2099 Al Li alloy cast-rolled sheets. [ABSTRACT FROM AUTHOR]

In recent years self-assembly has become progressively more "active", i.e. the focus of research gradually has shifted towards field-manipulation of matter in order to form temporary states rather than creating static architectures. The desire for time-programmed control of materials certainly originates from the unmatched complexity of natural systems that orchestrate multiple components across length scales. Although artificial self-assembly still lacks control comparable to natural systems, there has been impressive progress in a concerted approach from physicists, chemists, biologists, and engineers. This review summarizes the current trend in colloidal assembly advancing from static assembly of isotropic particles towards active structuring of anisotropic particles with heterogeneous (patchy) surfaces, and ultimately, to complex behavior in dissipative dynamic systems. We focus both on the formation of static structures and on temporary states due to response to magnetic, electric, or optic stimulation. We give examples of nano- and microparticle assembly where the temporary state may adopt equilibrium order or a continuously changing dynamic pattern. Image 1 [ABSTRACT FROM AUTHOR]

Motion of a point particle (a particle without any internal structure) in the context of special relativity is investigated. The study is based on the action principle with either time or the proper time regarded as the evolution parameter. Actions corresponding to the motion of particle in general external tensor fields are obtained. [ABSTRACT FROM AUTHOR]

The dependence of the magnetization and magnetic susceptibility of donor impurity in parabolic GaAs (Gallium Arsenide) quantum dot has been investigated, at finite temperature under the influence of external tilted electric and magnetic fields. Based on the effective mass approximation, the Hamiltonian of an electron confined in a parabolic quantum dot in the presence of donor impurity which is presented in electric and magnetic fields has been solved by employing the numerical diagonalization method of the Hamiltonian matrix. All the energy matrix elements have been obtained in analytical form. We have shown the variations of the statistical energy and binding energy of donor impurity with the electric and magnetic field strengths and tilt electric field angle. The computed results show that the electrical field can tune the magnetic properties of the QD GaAs medium by flipping the sign of its magnetic susceptibility from diamagnetic (χ < 0) to paramagnetic (χ > 0). [ABSTRACT FROM AUTHOR]

Designing novel transition metal dichalcogenides (TMDCs) are highly important for achieving superior performances in advanced optoelectrical devices of broad applications. Although many TMDCs materials have been synthesized and studied, the response behaviors of TMDCs under external excitations still lack in-depth investigations. To address this challenge, we have established a library of TMDCs including 56 types of materials and revealed their response behaviors to the external electric fields and strains as well as the possibility to drive phase transitions under the external excitations. We have explored the thermodynamic stability, band structures, electronic structures, and optical properties of these TMDCs. Under the external electric field, the gradual change of energy results in the conversion from semiconductors to metals, which enables the construction of heterojunctions while the Landau phase transitions are absent. In comparison, the external strain not only lowers the overall symmetry but also induces strong p-π hybridizations to realize unique electronic properties. In particular, Dirac cones are noticed in the 1H-TcTe 2 within 45–100 GPa, supporting a novel quasi heavy-fermion topological Kondo insulator induced by the phase transition under the external strains for the first time in TMDCs. This work offers fundamental knowledge to discover novel TMDCs candidates with superior optoelectrical properties. [Display omitted] • A library including of monolayer transition metal dichalcogenides is established for response behaviors to external fields. • The external electric field can switch the original left-hand rule for intrinsic properties to the converse right-hand rule. • The external strain induce the first-order Landau phase transition behaviors. • Dirac cone is observed for the first time in 2D transition metal dichalcogenides induced by external strains. [ABSTRACT FROM AUTHOR]

External fields such as gravitational, centrifugal or electrical fields lead to an uneven spatial distribution of the chemical compounds of a system. In this work, we conceive a scenario where a packing bed is submitted to a centrifugal field, so that centrifugation and adsorption occur simultaneously. Our rotating packed bed is made up by two main regions: one, representing the bulk phase, the other, representing the total pore volume available for adsorption. At constant temperature, total volume, and total amount, the distribution of species of selected binary and ternary mixtures of hydrocarbons, carbon dioxide, and hydrogen sulfide is predicted by minimizing the total Helmholtz energy of the system. Confinement-modified equations of state are employed as thermodynamic model for the adsorbed phase, while the Peng-Robinson equation of state is used in bulk phase calculations. Our purely thermodynamic analysis reveal that coupling both phenomena could be useful to enhance adsorption, or increase the separation obtained when only centrifugation is considered. [ABSTRACT FROM AUTHOR]

[Display omitted] • The electronic properties are strongly affected by magnetic field and bias voltage. • The 3L-SiC is semiconductor and by applying theexternal fields, transforms from the to metallic. • The thermoelectric properties of the 3L-SiC have been strongly modiefied by external fields and temperature. • In absence of the external fields, the thermal properties of the 3L-SiC is larger than that 3L-BN. • Whit stronger fields, the thermal properties of the 3L-BN can be enhanced in order to 3L-SiC independent to its wide band gap. The two-dimensional semiconducting materials with tunable electronic structure and high thermoelectric properties have a wide range of applications, especially in nanoscale devices. This study uses the Kubo-Greenwood formula in the framework of the Green function approach and the tight binding model to calculate the thermoelectric properties of trilayer SiC (3L-SiC). 3L-SiC is a semiconductor that can transform to metallic state with increasing applying the external fields with critical strength. The thermoelectric properties of the 3L-SiC and 3L-BN were analyzed under bias voltage, magnetic field and temperature up to 1500 K and compared with each other. The results show that thermal properties of the 3L-SiC are higher than that 3L-BN and both structures exhibit strong dependence on bias voltage and magnetic field with higher sensitivity to the magnetic field. The thermal properties of the selected structures increases with temperature and the external fields enhance the increasing rate. The behavior of the Lorenz Number in terms of temperature exhibits general pattern as increasing from zero to maximum value at TM and decreasing by further temperature increasing. [ABSTRACT FROM AUTHOR]

Influence of Rashba and Dresselhaus spin orbit interactions (SOIs) as well as external magnetic and electric fields on optical behaviors of quantum rings (QRs) were studied. To achieve this purpose, the matrix diagonalization method was exerted to compute energy eigenvalues of the system in the presence of electric and magnetic fields. Besides, the compact density matrix approach was used to calculate the refractive index (RI) and absorption coefficient (AC) of 1 → 2, 1 → 3, 1 → 6 and 3 → 5 transitions. Moreover, by increasing the magnetic (B) and electric (F) fields, energy splitting of intersubband energy levels was increased and thus the RIs and ACs of the system are changed. The results clearly show that, position and peak value of total RIs and ACs curves of all transitions experienced significant change by increasing the magnetic and electric fields in the presence of SOIs. Finally, the effect of size variation on optical RI changes and ACs was studied. The results show that the higher inner radii, R 1 , is, the stronger quantum confinement and energy increase are. These results are relevant for the designing of spin-based devices. [ABSTRACT FROM AUTHOR]

In this paper equilibrium measures in the presence of external fields created by fixed charges are analyzed. These external fields are a particular case of the so-called rational external fields (in the sense that their derivatives are rational functions). Along with some general results, a thorough analysis of the particular case of two fixed negative charges (“attractors”) is presented; indeed, the main result of the paper deals with this particular case. As for the main tools used, this paper is a natural continuation of [31] , where polynomial external fields were thoroughly studied, and [37] , where rational external fields with a polynomial part were considered. However, the absence of the polynomial part in the external fields analyzed in the current paper adds a considerable difficulty to solve the problem and justifies its separated treatment; moreover, it is noteworthy to point out the simplicity and beauty of the results obtained. [ABSTRACT FROM AUTHOR]

After the tremendous advances over the past two decades, micro-/nanorobots can effectively convert other forms of energy into propulsion and movement, as well as be navigated to targeted locations under physiological conditions and environments. They have been demonstrated to have the potential to load, transport, and deliver therapeutic payloads directly to disease sites, thereby improving the therapeutic efficacy and reducing systemic side effects of highly toxic drugs. In this feature article, the various propulsion modalities of micro-/nanorobots ranging from chemical/biochemical reactions to external fields, and to motile microorganisms are summarized and commented in terms of driving forces required by the automotive motion in biological media, biocompatibility, as well as the corresponding advantages and limitations in terms of biomedical applications. Then, the latest developments of in vitro and in vivo active drug delivery based on micro-/nanorobots are discussed in detail. The challenges and future prospects are also highlighted in the end. With ever booming research enthusiasm in this field and increasing multidisciplinary cooperation, micro-/nanorobots with intelligence and multifunctions will emerge in the near future, which would have a profound impact on the treatment of diseases. [ABSTRACT FROM AUTHOR]

In the present work, the optical properties of GaAs/AlGaAs semiparabolic quantum wells (QWs) are studied under the effect of applied electric field and magnetic field by using the compact-density-matrix method. The energy eigenvalues and their corresponding eigenfunctions of the system are calculated by using the differential method. Simultaneously, the nonlinear optical rectification (OR) and optical absorption coefficients (OACs) are investigated, which are modulated by the applied electric field and magnetic field. It is found that the position and the magnitude of the resonant peaks of the nonlinear OR and OACs can depend strongly on the applied electric field, magnetic field and confined potential frequencies. This gives a new way to control the device applications based on the intersubband transitions of electrons in this system. [ABSTRACT FROM AUTHOR]