Dual Field Research Articles

Artificial intelligence-driven bioenergy system: digital green innovation partner selection of bioenergy enterprises based on interval fuzzy field model

PurposeThe aim of this study is to (1) construct a standard framework for assessing the capability of bioenergy enterprises' digital green innovation partners; (2) quantify the choice of partners for digital green innovation by bioenergy enterprises; (3) propose based on a dual combination empowerment niche digital green innovation field model.Design/methodology/approachFuzzy set theory is combined into field theory to investigate resource complementarity. The successful application of the model to a real case illustrates how the model can be used to address the problem of digital green innovation partner selection. Finally, the standard framework and digital green innovation field model can be applied to the practical partner selection of bioenergy enterprises.FindingsDigital green innovation technology of superposition of complementarity, mutual trust and resources makes the digital green innovation knowledge from partners to biofuels in the enterprise. The index rating system included eight target layers: digital technology innovation level, bioenergy technology innovation level, bioenergy green level, aggregated digital green innovation resource level, bioenergy technology market development ability, co-operation mutual trust and cooperation aggregation degree.Originality/valueThis study helps to (1) construct the evaluation standard framework of digital green innovation capability based on the dual combination empowerment theory; (2) develop a new digital green innovation domain model for bioenergy enterprises to select digital green innovation partners; (3) assist bioenergy enterprises in implementing digital green innovation practices.

The dual built-in electric fields across CoS/MoS2 heterojunctions for energy-saving hydrogen production coupled with sulfion degradation

Substituting the sluggish oxygen evolution reaction with the sulfur oxidation reaction can significantly reduce energy consumption and eliminate environmental pollutants during hydrogen generation. However, the progress of this technology has been hindered due to the lack of cost-effective, efficient, and durable electrocatalysts. In this study, we present the design and construction of a hierarchical metal sulfide catalyst with a gradient structure comprising nanoparticles, nanosheets, and microparticles. This was achieved through a structure-breaking sulfuration strategy, resulting in a “ball of yarn”-like core/shell CoS/MoS2 microflower with CoS/MoS2/CoS dual-heterojunctions. The difference in work functions between CoS and MoS2 induces an electron polarization effect, creating dual built-in electric fields at the hierarchical interfaces. This effectively modulates the adsorption behavior of catalytic intermediates, thereby reducing the energy barrier for catalytic reactions. The optimized catalyst exhibits outstanding electrocatalytic performance for both the hydrogen evolution reaction and the sulfur oxidation reaction. Remarkably, in the assembled electrocatalytic coupling system, it only requires a cell voltage of 0.528 V at 10 mA cm−2 and maintains long-term durability for over 168 h. This work presents new opportunities for low-cost hydrogen production and environmentally friendly sulfion recycling.

Temporal evolution and spectral characteristics of dual field in a double-pumped microcavity

To generate dual combs for various precision measurements, the temporal evolution and spectral characteristics of dual fields in a double-pumped microcavity are investigated. Results show that by using dual orthogonally polarized pumps, the dual fields can be controlled by regulating the two detunings. The coexistence of solitons and Turing patterns, which is equivalent to dual-frequency combs with a large repetition frequency difference, can be excited. Two positive detuning parameters are similar, and two soliton pulses with identical free spectral ranges and different intensities are formed. Moreover, two weaker positive detunings are beneficial for the dual Turing patterns. Furthermore, breathers and multiple pulses can be excited under special conditions. The effects of dispersion and pump intensity on the dual fields are also studied. Dual combs exist in an anomalous dispersion regime and the strong negative dispersion only leads to DC fields. For the pump intensity, with the increase of pumping power, one field experiences breathers and variable multi-pulse in sequence while the other field maintains Turing patterns. The results of this study provide a new approach to excite dual-frequency combs by using a single microcavity.

Theoretical Analysis and Experimental Research on the Apple Auto-Orientation Based on Flexible Roller

After automatic in-field picking, apple stem shortening requires fixing the apple position and maintaining a relatively stable posture, which puts high demands on the automatic apple-orienting structure. In this paper, a novel dual roller compact apple field orientation structure with dual rollers rotating in the same direction is proposed. It can realize the uniform orientation of apples after automatic picking in any attitude, and the apple auto-orientation phenomenon is theoretically analyzed based on the accurately established apple model, then the apple orientation test platform was set up and a monocular camera combined with YOLOv5m was used to determine the time of apple orientation. The results showed that 70.21% and 96.81% of the apples were respectively oriented within 7 s and 28 s with only two flexible rollers rotating in the corresponding direction. All the apples were oriented, and 95.24% of them moved along the axis toward the calyx end. The generalizability of the apple orientation device for different shapes of apples was then verified, and the relationship between the shape characteristics of apples and orientation speed was later illustrated. A structural basis was finally presented for automatic stem shortening and surface damage detection in the apple field.

Multilevel hollow hierarchical heterostructure with DB-IEF and space-confined effect for enhanced bifunctional PHE/HER activity

In photocatalytic/electrocatalytic water splitting processes, charge carriers are the main limiting factor of enhanced yield, and the enhanced charge dynamics related to the generation, transport, separation and utilization of charge is considered to be an effective measure to solve the above problems. In this study, multilevel hollow hierarchical In2S3/ZnIn2S4/CdIn2S4 (IS/ZIS/CIS) with heterogeneous spatial confinement was successfully prepared by one-step solvothermal method. The strong dual cascade built-interface electric field (DB-IEF) of the IS, ZIS and CIS contact interfaces (ISⅠZIS and ZISⅠCIS) is beneficial for migrating electrons and tailoring the electronic structures of the active centers near the ISⅠZIS and ZISⅠCIS interfaces. The as-constructed IS/ZIS/CIS shows outstanding bifunctional photocatalytic/electrocatalytic water splitting activity, which can not only offer high electrocatalytic activities toward HER with a low overpotential of 61 mV (vs. RHE) at 10 mA ·cm−2, with low Tafel slopes of 68 mV·dec-1 in alkaline solutions, but also achieve a higher H2 evolution rate of 4.42 mmol g−1·h−1. Meanwhile, the Brunauer-Emmett-Teller surface area (BET) and pore size distribution revealed that multilevel hollow hierarchical IS/ZIS/CIS heterostructure owns hierarchical microporous/mesoporous structure, which facilitates light absorption and multiple reflections. The efficiently interfacial charge transfer and bifunctional catalytic activity could be attributed to the established DB-IEF and spatial confinement effect could drive carrier transmission, realize effective charge separation, utilization, and prolong lifetimes. This work can provide a new synthesis strategy of establishing the hierarchical heterostructure catalysts for boosting charge transfer and photocatalytic/electrocatalytic water splitting.

Boosting nitrogen adsorption for photocatalytic ammonia production via tuning electron distribution using zero valent iron as medium

Photocatalytic nitrogen reduction to ammonia plays an important role in agricultural production and now-generation hydrogen storage technology. However, the practicality is limited by low efficiency owing to the poor charge-transfer rate and slow ammonification reactions. Herein, a ternary Fe2O3-Fe-HCNS composite is reported with all-solid-state Z-scheme heterojunction, which zero valent iron (ZVI) with abundant electrons is employed as conductor between hollow g-C3N4 sphere (HCNS) and Fe2O3. ZVI facilitates photogenerated electrons transfer and changes charge distribution on the Fe2O3-Fe-HCNS surface, thus an electron-rich region is formed around HCNS, which improves N2 adsorption and ammonification reaction on the HCNS surface. Moreover, the dual interfacial electric fields are established in the heterojunction, which can promote efficient separation and migration of photo-induced electrons and holes in space, leading to the good photocatalytic performances with the higher ammonia yield (296.30 μmol g−1h−1) and apparent quantum yield (1.38%, 400 nm) in neutral electrolytes. In addition, compared with the catalyst powder, vertical carbon paper supporting Fe2O3-Fe-HCNS catalyst can reduce secondary pollution and facilitate recycling.

The cosmological constant is probably still zero

We consider a wide class of four-dimensional effective field theories in which gravity is coupled to multiple four-forms and their dual scalar fields, with membrane sources charged under the corresponding three-form potentials. Four-form flux, quantised in units of the membrane charges, generically generates a landscape of vacua with a range of values for the cosmological constant that is scanned through membrane nucleation. We list various ways in which the landscape can be made sufficiently dense to be compatible with observations of the current vacuum without running into the empty universe problem. Further, we establish the general criteria required to ensure the absolute stability of the Minkowski vacuum under membrane nucleation and the longevity of those vacua that are parametrically close by. This selects the current vacuum on probabilistic grounds and can even be applied in the classic model of Bousso and Polchinski, albeit with some mild violation of the membrane weak gravity conjecture. We present other models where the membrane weak gravity conjecture is not violated but where the same probabilistic methods can be used to tackle the cosmological constant problem.

Generating characteristics and experimentation of counter rotating dual rotor wound field flux switching wind generator

AbstractIn this paper, counter rotating dual rotor wound field flux switching wind power generator is revisited to study the generating characteristics of the AC output power curves based on finite element analysis (FEA) and experimental study. Analysis are performed under dynamic conditions, such as variable resistance, field excitation and speed. Also, electromagnetic performance is studied under variation of the field and armature currents. Analysis reveals that outer port machines with higher power capability and better electromagnetic performance compared to the inner port counterparts, although with higher fluctuations exhibited on the torque profiles of the former due to higher slotting effects. From the power generation characteristics curves, it is clear that the developed wind generator is able to produce reliable performance over a wide operating range. The accuracy of the FEA predicted results are validated, experimentally.The cover image is based on the Research Article Generating characteristics and experimentation of counter rotating dual rotor wound field flux switching wind generator by Wasiq Ullah et al., https://doi.org/10.1049/elp2.12374.

Q-Form Field on a p-Brane with Codimension Two

This paper investigates gauge invariance in a bulk massless q-form field on a p-brane with codimension two, utilizing a general Kaluza–Klein (KK) decomposition. The KK decomposition analysis reveals four distinct KK modes: the conventional q-form, two (q−1)-forms and one (q−2)-form. These diverse modes are essential for maintaining gauge invariance. We also find eight Schrödinger-like equations for the four modes due to the two extra dimensions, and their mass spectra are closely related. The KK decomposition process gives rise to four dualities on the p-brane, originating from the inherent Hodge duality present in the bulk. Notably, these dual symmetries play a significant role in maintaining the equivalence of bulk dual fields during dimensional reduction.

Flow of shear response functions in hyperscaling violating Lifshitz theories

We study the flow equations of the shear response functions for hyperscaling violating Lifshitz (hvLif) theories, with Lifshitz and hyperscaling violating exponents z and theta . Adapting the membrane paradigm approach of analysing response functions as developed by Iqbal and Liu, we focus specifically on the shear gravitational modes which now are coupled to the perturbations of the background gauge field. Restricting to the zero momenta sector, we make further simplistic assumptions regarding the hydrodynamic expansion of the perturbations. Analysing the flow equations shows that the shear viscosity at leading order saturates the Kovtun–Son–Starinets (KSS) bound of frac{1}{4pi }. When z=d_i-theta , (d_i being the number of spatial dimension in the dual field theory) the first-order correction to shear viscosity exhibits logarithmic scaling, signalling the emergence of a scale in the UV regime for this class of hvLif theories. We further show that the response function associated to the gauge field perturbations diverge near the boundary when z>d_i+2-theta . This provides a holographic understanding of the origin of such a constraint and further vindicates results obtained in previous works that were obtained through near horizon and quasinormal mode analysis.

Research on dual lateral log simulation of shale bedding fractures under different influencing conditions

Micro scale fractures play a crucial role in facilitating the migration of oil and gas in low permeability shale reservoirs. However, the identification of such fractures is a complex task. The efficacy of the dual lateral log physical field changes as a means of identifying shale micro fractures remains uncertain. To address this issue, a three-layer shale bedding fracture model was developed using the finite element method and core and conventional logging data from eight wells, which was based on different shale reservoirs within the Yanchang Formation in the Ordos Basin. The present study examines the dual lateral log response characteristics resulting from distinct characteristics of horizontal bedding fractures, with a focus on the response mechanism. The simulation of logging response characteristics of shale and siltstone combination were utilized by core statistical data for verification purposes. The results indicate that under the lithology combination of shale and siltstone, the magnitude of the difference between the resistivity of the filled fracture and the formation resistivity, the greater the formation resistivity of the shale itself, the wider the fracture width, and the greater the difference between the apparent resistivity and the real formation resistivity. Furthermore, the suitable conditions for the detection of shale bedding fracture characteristics by dual lateral log are clarified. In the presence of effective filling, the dual lateral log has the capability to identify shale fractures at the micron scale. The findings of our study establish a theoretical framework for the identification and assessment of shale fractures, and furnish technical assistance for the optimal selection of “sweet spots” within shale reservoirs and the precise evaluation of reservoirs. This study lays a theoretical foundation for the identification and evaluation of shale fractures, and provides technical support for the optimal “sweet spot” selection of shale reservoirs and the accurate evaluation of reservoirs.

Anisotropic Scaling Non-Relativistic Holography: A Symmetry Perspective

We study the holographic dual of the two-dimensional non-relativistic field theory with anisotropic scaling from a symmetry perspective. We construct a new four-dimensional metric with two-dimensional global anisotropic scaling isometry. The four-dimensional spacetime is homogeneous and is a solution of Einstein gravity with quadratic-curvature extension. We consider this spacetime dual to the vacuum of the boundary field theory. By introducing a proper solution phase space, we find that the asymptotic symmetry of the gravity theory is the two-dimensional local anisotropic conformal symmetry, which recovers precisely the results from the dual non-relativistic field theory side.

Tip effect and structural disordering in Bi2WO6 for enhanced piezo-photocatalytic nitrogen oxidation to nitric acid

Piezo-photo coupling effect in charge separation has garnered substantial attention in recent research. However, the piezoelectricity-induced charges are inevitably depleted by the photoinduced current near the interface. Herein, we propose a meticulously designed conformity-directional dual electric field by introducing the tip effects and structural disordering in Bi2WO6. In the absence of cocatalysts, Bi and O vacancies rich Bi2WO6 with a Bi0 cluster (Bi0/Bi2−xWO6−x, BBW) exhibited remarkable piezo-photocatalytic nitrogen oxidation to nitric acid rates (5.26 mg g−1 h−1), which is 5 times that of pure Bi2WO6. Theoretical and experimental results demonstrated that the cluster and vacancies acted as the major strain and potential center, which can be referred to as the “tip effect” and structural disordering that enhanced the piezoelectric-polarization electric field and the photoinduced built-in electric field along the same direction to promote charge transfer and exciton dissociation. Moreover, the cluster and vacancies acted as activation sites for O2 and N2, reducing the surface reaction barrier. Thus, the proposed method will aid in designing dual-polarization electric fields for enhancing carrier separation.

Physical insights into the reliability of sunken source connected field plate GaN HEMTs for mm-wave applications

This article investigates the incorporation of field plates in AlGaN/GaN High Electron Mobility Transistors (HEMTs) which leading to enhancement in the device breakdown voltage and a reduction in the reverse leakage current. Using Atlas TCAD software breakdown behavior of gate-connected field plate (GFP), gate-source (dual) field plate, and discrete source-connected field plate (Sunken SC-FP) designs with field plate length variation is probed and physical insight is developed through electric field profile, and impact ionization contour plots. By employing a Sunken SC-FP with gate length of 0.4 μm in the gate-drain access region the device breakdown voltage is improved and has high JFOM (4.8 THz·V). Also, on-resistance (RON) degradation is minimum in the Sunken SCFP (20.12 %), compared with GFP (31.20 %) and dual FP (24.96 %) architectures, when the device is stressed in the off-state (VGS = −40 V) for 1 min. The RF performance of the Sunken SC-FP HEMT is studied using small signal parameters and the load pull measurements as a function of drain bias.

Gravitational Blocks, Spindles and GK Geometry

We derive a gravitational block formula for the supersymmetric action for a general class of supersymmetric AdS solutions, described by GK geometry. Extremal points of this action describe supersymmetric AdS_3 solutions of type IIB supergravity, sourced by D3-branes, and supersymmetric AdS_2 solutions of D=11 supergravity, sourced by M2-branes. In both cases, the branes are also wrapped over a two-dimensional orbifold known as a spindle, or a two-sphere. We develop various geometric methods for computing the gravitational block contributions, allowing us to recover previously known results for various explicit supergravity solutions, and to significantly generalize these results to other compactifications. For the AdS_3 solutions we give a general proof that our off-shell supersymmetric action agrees with an appropriate off-shell c-function in the dual field theory, establishing a very general exact result in holography. For the AdS_2 solutions our gravitational block formula allows us to obtain the entropy for supersymmetric, magnetically charged and accelerating black holes in AdS_4.

Stochastic quantization and holographic Wilsonian renormalization group of scalar theory with generic mass, self-interaction and multiple trace deformation

We explore the mathematical relationship between holographic Wilsonian renormalization group (HWRG) and stochastic quantization (SQ) of scalar field theory with its generic mass, self-interaction and [Formula: see text]-multiple-trace deformation on the [Formula: see text]-dimensional conformal boundary defined in AdS[Formula: see text] space–time. We understand that once we define our Euclidean action, [Formula: see text] as [Formula: see text], then the stochastic process will reconstruct the HWRG data via solving Langevin equation and computing stochastic correlation functions. The [Formula: see text] is given by [Formula: see text], where [Formula: see text] is the boundary counter term and [Formula: see text] is the boundary deformation which gives a boundary condition. In our study, we choose the boundary condition adding (marginal)[Formula: see text]-multiple-trace deformation to the holographic dual field theory. In this theory, we establish maps between fictitious time, [Formula: see text] evolution of stochastic [Formula: see text]-point, ([Formula: see text])-point correlation functions and the (AdS)radial, [Formula: see text] evolution of [Formula: see text]-multiple-trace and ([Formula: see text])-multiple-trace deformations, respectively, once we take identifications of [Formula: see text] and between some of the constants appearing in both sides.

Efficient piezo-photocatalysis of 0D/2D α-Fe2O3/Bi2WO6: Synergy of weak force-driven piezoelectric polarization and Z-scheme junction

Photocatalysis shows huge potential in environmental purification, but suffers from fast photocharge recombination and finite photoabsorption. Piezoelectric polarization is perceived as a promising approach to drive charge separation, but it always relies on the energy-guzzling ultrasonic vibration. Herein, a piezo-photocatalytic system integrating dual electric fields constructed by weak force-driven piezoelectric polarization and Z-scheme junction is developed in 0D/2D α-Fe2O3/Bi2WO6. The introduction of low-frequency water flow-induced piezoelectric polarization field accelerates the migration of bulk photoexcited carriers of polar Bi2WO6, and forming Z-scheme junction with intimate interface guarantees the spatial separation of interfacial charges and strong visible light response. Benefiting from these merits, water flow-triggered α-Fe2O3/Bi2WO6 delivers a superb tetracycline hydrochloride photodegradation efficiency of 82% within 20 min, which outperforms related piezo-photocatalysts in previous reports, even those driven by high-frequency ultrasound. KPFM and DFT calculations provide forceful evidence for the Z-scheme transfer pathway between α-Fe2O3 and Bi2WO6. Additionally, the synergetic effect of constructing the Z-scheme junction and introducing piezoelectric polarization is well confirmed by PFM, COMSOL simulation, ESR and photoelectrochemical characterization. This work offers a novel strategy to design the piezo-photocatalytic system and maybe realize the in-situ treatment of sewage taking full advantage of hydrodynamic characteristics.

Bulk Landau pole and unitarity of dual conformal field theory

The singlet sector of the O(N) ϕ4-model in AdS4 at large-N, gives rise to a dual conformal field theory on the conformal boundary of AdS4, which is a deformation of the generalized free field. We identify and compute an AdS4 three-point one-loop fish diagram that controls the exact large-N dimensions and operator product coefficients (OPE) for all “double trace” operators as a function of the renormalized ϕ4-couplings. We find that the space of ϕ4-coupling is compact with a boundary at the bulk Landau pole. The dual CFT is unitary only in an interval of negative couplings bounded by the Landau pole where the lowest OPE coefficient diverges.

Shift Symmetries and AdS/CFT

Massive fields on anti-de Sitter (AdS) space enjoy galileon-like shift symmetries at particular values of their masses. We explore how these shift symmetries are realized through the boundary conformal field theory (CFT), at the level of the 2-point functions. In the alternate quantization scheme in which the dual conformal field gets the smaller ∆− conformal dimension, the shift symmetry is realized as a gauge symmetry in the dual CFT, so that only shift invariant operators are true conformal primary fields. In the standard quantization scheme the shift symmetry acts on the source, leading to Ward identities that take the form of integral constraints.

T1,1 truncation on the spindle

We study the compactification of the \U0001d4a9 = 2 AdS5 consistent truncation of the conifold, in presence of a Betti vector multiplet, on the spindle. We derive the BPS equations and solve them at the poles, computing the central charge for both the twist and the anti-twist class, turning on the magnetic charge associated to the baryonic symmetry. Then, in the anti-twist class, where there are choices of the quantized flux that give origin to a positive central charge, we numerically solve the BPS equations interpolating between the poles of the spindle. We conclude by comparing our results with the one obtained from the analysis of the dual field theory, finding an exact agreement.