bluuebunny/crossref_metadata_2025 huggingface dataset:
High-performance photon number resolving detectors for 850–950 nm wavelength range
Authors: Los J. W. Niels , Sidorova Mariia , Lopez-Rodriguez Bruno , Qualm Patrick , Chang Jin , Steinhauer Stephan , Zwiller Val , Zadeh Iman Esmaeil
Published: June 2024

Since their first demonstration in 2001 [Gol’tsman et al., Appl. Phys. Lett. 79, 705–707 (2001)], superconducting-nanowire single-photon detectors (SNSPDs) have witnessed two decades of great developments. SNSPDs are the detector of choice in most modern quantum optics experiments and are slowly finding their way into other photon-starved fields of optics. Until now, however, in nearly all experiments, SNSPDs were used as “binary” detectors, meaning that they could only distinguish between 0 and >=1 photons, and photon number information was lost. Recent research has demonstrated proof-of-principle photon-number resolution (PNR) SNSPDs counting 2–5 photons. The photon-number-resolving capability is highly demanded in various quantum-optics experiments, including Hong–Ou–Mandel interference, photonic quantum computing, quantum communication, and non-Gaussian quantum state preparation. In particular, PNR detectors at the wavelength range of 850–950 nm are of great interest due to the availability of high-quality semiconductor quantum dots (QDs) [Heindel et al., Adv. Opt. Photonics 15, 613–738 (2023)] and high-performance cesium-based quantum memories [Ma et al., J. Opt. 19, 043001 (2017)]. In this paper, we demonstrate NbTiN-based SNSPDs with >94% system detection efficiency, sub-11 ps timing jitter for one photon, and sub-7 ps for 2 photons. More importantly, our detectors resolve up to 7 photons using conventional cryogenic electric readout circuitry. Through theoretical analysis, we show that the PNR performance of demonstrated detectors can be further improved by enhancing the signal-to-noise ratio and bandwidth of our readout circuitry. Our results are promising for the future of optical quantum computing and quantum communication.
Primary processes of the archetypal model complex azido(porphinato)iron(III) from ultrafast vibrational–electronic spectroscopy
Authors: Flesch Stefan , Domenianni Luis I. , Vöhringer Peter
Published: June 2024

Azidoiron complexes serve as valuable photochemical precursors for catalytically active species containing high-valent iron. In bioinorganic chemistry, azido(tetraphenylporphinato)iron(III), i.e., [FeIII(tpp)(N3)] with tpp = 5, 10, 15, 20-tetraphenylporphyrin-21, 23-diido, constitutes the archetypal model system that was used to access for the first time the terminal nitridoiron core, FeV ≡ N, in the biomimetic redox-non-innocent ligand environment. So far, the light-induced dynamics leading to the oxidation of the metal and the release of dinitrogen from the N3-ligand have only been studied for precursors featuring redox-innocent auxiliary ligands that simplify the electronic structure change accompanying the photo-transformation. Here, we monitored the primary events of the above paradigmatic complex, following its optical excitation in the ultraviolet-to-visible spectral range using femtosecond spectroscopy with probing in both the UV–vis and mid-infrared regions. Following ultrafast Soret-excitation at 400 nm, the complex relaxes to the lowest excited sextet state by a first internal conversion in less than 200 fs. The excited state then undergoes vibrational relaxation on a time scale of roughly 2 ps before internally converting yet again to recover the sextet electronic ground state within 19.5 ps. Spectroscopic evidence is obtained neither for a transient occupation of the energetically lowest metal-centered state, 41A1, nor for vibrational relaxation in the ground-state. The primary processes seen here are thus in contrast to those previously derived from ultrafast UV-pump/vis-probe and UV-pump/XANES-probe spectroscopies for the halide congener [FeIII(tpp)(Cl)]. Any photochemical transformation of the complex arises from two-photon-induced dynamics.
Analysis of output characteristics of positive feedback piezoelectric energy harvester based on nonlinear magnetic coupling
Authors: Shi Rui , Chen Jiawei , Ma Tianbing , Li Changpeng , Zhang Wenjie , Ye Dongdong
Published: June 2024

In light of the limitations of the current piezoelectric energy harvesters and the demand for self-power supply in wireless sensor nodes, a novel positive feedback piezoelectric energy harvester based on nonlinear magnetic coupling is proposed. The operational characteristics of this energy harvester are investigated from three perspectives: theory, simulation, and experiment. First, a nonlinear electromechanical coupling mathematical model that describes the dynamic response of the energy harvester system is established by combining the Hamilton variational principle with the piezoelectric theory. This provides a theoretical foundation for subsequent research. Second, finite element method simulations are employed to optimize the structural parameters of the energy harvester and study the impact of nonlinear magnetic force on its output performance. Finally, an experimental prototype is fabricated and an experimental test system is constructed to validate the designed positive feedback piezoelectric energy harvester. The results demonstrate that changes in the longitudinal beam angle have minimal effect on energy capture efficiency. By appropriately increasing the bending surface length, reducing initial magnetic moment, and augmenting mass block weight, wider working frequency bands and higher power generation capacity can be achieved when vibrating in low-energy orbits. The experimental findings align closely with theoretical design values and contribute to advancing broadband multi-directional piezoelectric energy harvesting technology in order to provide high-performance vibration-based power solutions for wireless applications.
Corium interface flow dynamics investigation during severe accident in pressurized water reactors using compressive advection interface capturing method
Authors: Ajah Stephen A. , Akanji Lateef , Gomes Jefferson
Published: June 2024

Past nuclear accident occurrences raised strong concerns which led to research on nuclear safety. One of the major causes of nuclear accidents is the impeded circulation of core coolant, leading to decay heat removal cessation and rapid temperature rise. If uncontrolled, this results in critical heat flux, loss of coolant accidents, and core dryout. Detailed melted core relocation (i.e., nuclear fuel, graphite, and zircaloy) needs to be investigated through interface capture and multimaterial flow model coupling, which have not been done in previous studies. This work aims to investigate the impacts of temperature and core material composition on the flow dynamics during core relocation. In this study, mass fraction is discretized using a streamlined upwind Petrov–Galerkin method spatially and a modified Crank–Nicolson method temporally to accurately capture fluid interfaces using a high-order accurate flux-limiter. Two core material composition cases (individual material properties case and bulk material properties case) were considered to assess the impact of temperature and core materials composition on both flow dynamics and computational time. Temperature has a significant impact on core material transport and corium flow dynamics during core relocation. Bulk materials properties case has greater impact of temperature on its corium resulting in faster materials transport, but with higher computation time.
Broadband and polarization sensitive quasi-1D Nb2Pd3Se8 photodetector
Authors: Wang Cong , Wang Kunpeng , Wen Keyu , Zhang Libo , Liu Xue , Zhu Xiangde , Tian Mingliang , Wang Jun-Lei , Chen Xuegang
Published: June 2024

High-performance photodetectors (PDs) find potential applications in extensive areas such as self-driving vehicles, resource monitoring, imaging, communication, etc. However, low sensitivity, slow response speed, and poor air stability have limited their application. In this work, we construct an air stable one-dimensional ternary transition metal chalcogenide Nb2Pd3Se8-based PD that has high sensitivity and fast response and is polarization-sensitive. The Nb2Pd3Se8 nanowire-based PD shows a maximum responsivity of 47 A W−1, a detectivity of 3.28 × 1011 Jones, and a response time of 50–65 µs under 520 nm laser illumination. In addition, the 1D PD shows polarization-sensitivity with a 0.47 anisotropic ratio. This performance paves way to construct robust air stable PDs with high detectivity and high responsivity using one-dimensional Nb2Pd3Se8-based nanostructures.
Quantum spin Hall insulating phase in two-dimensional MA2Z4 materials: SrTl2Te4 and BaTl2Te4
Authors: D'Souza Joel , Verzola Ina Marie R. , C Sreeparvathy P. , Villaos Rovi Angelo B. , Huang Zhi-Quan , Chuang Feng-Chuan
Published: June 2024

With the recent synthesis of two-dimensional (2D) MoSi2N4, the 2D material family with the general formula MA2Z4 has become increasingly popular. However, their topological properties have yet to be explored. Using first-principles calculations, we examine the electronic and topological properties of monolayer MA2Z4 (M = Ca, Sr, or Ba; A = In or Tl; Z = S, Se, or Te) compounds. Our study reveals the quantum spin Hall phase in SrTl2Te4 and BaTl2Te4 with a nontrivial topological bandgap of 97 and 28 meV, respectively, under a hybrid functional approach with the inclusion of spin–orbit coupling. Remarkably, the Z2 topological invariant and the presence of gapless edge states further confirmed their nontrivial topological phase. In addition, we demonstrate the quantized spin Hall conductivity in SrTl2Te4, which stems from the non-zero Berry curvature. The topological phase transition is driven by SOC due to the band inversion between the Te-px+py and Tl-s orbitals around Γ. Interestingly, the nontrivial topological properties are robust against strain and preserved under an applied electric field. Finally, our research identifies that the emergent MA2Z4 monolayers have interesting topological properties and have great potential for experimental realization of future topological applications.
Linear and nonlinear optics in composite systems: From diagrammatic modeling to applications
Authors: Noblet Thomas , Busson Bertrand
Published: June 2024

A bipartite system is defined as two microscopic entities being able to exchange energy. When excited by light, the complete optical response functions at first (polarizabilities) and second orders (first hyperpolarizabilities) of such a system are determined using the diagrammatic theory of optics. The generality of the method is ensured by the free choice of light–matter and matter–matter interaction Hamiltonians and by the arbitrary number of quanta involved in the energy exchange. In the dipolar approximation, the optical response functions of the system (i.e., of the interacting entities) are linked to the responses of the interaction-free entities by transfer matrices. These universal matrices identically modify the optical response functions at all orders in the electromagnetic field, allowing the implementation of matter–matter interactions in higher-order processes, such as stimulated or spontaneous Raman scattering and four-wave mixing. This formalism is then applied to various composite systems: dimers, multimers and lattices of nanoparticles and molecules, dense molecular layers, and substrate-induced image dipoles.
Numerical stability analysis of Godunov-type schemes for high Mach number flow simulations
Authors: Ren Weijie , Xie Wenjia , Zhang Ye , Yu Hang , Tian Zhengyu , Zhu Jiajun
Published: June 2024

Modern shock-capturing schemes often suffer from numerical shock instabilities when simulating strong shocks, limiting their application in supersonic or hypersonic flow simulations. In the current study, we devote our efforts to investigating the shock instability problem for second-order schemes, which has not gotten enough attention in previous research but is crucial to address. To this end, we develop the matrix stability analysis method for the finite-volume Monotone Upstream-centered Schemes for Conservation Laws (MUSCL) approach, taking into account the influence of reconstruction. With the help of this newly developed method, the shock instability of second-order schemes is investigated quantitatively and efficiently. The results demonstrate that when second-order schemes are employed, whether shock instabilities will occur is closely related to the property of Riemann solvers, just like the first-order case. However, enhancing spatial accuracy still impacts the shock instability problem, and the impact can be categorized into two types depending on the dissipation of Riemann solvers. Furthermore, the research emphasizes the impact of the numerical shock structure, highlighting both its role as the source of instability and the influence of its state on the occurrence of instability. One of the most significant contributions of this study is the confirmation of the multidimensional coupled nature of shock instability. Both one-dimensional and multidimensional instabilities are proven to influence the instability problem, and they have different properties. Moreover, this paper reveals that increasing the aspect ratio and distortion angle of the computational grid can help mitigate shock instabilities. The current work provides an effective tool for quantitatively investigating the shock instabilities for second-order schemes, revealing the inherent mechanism and thereby contributing to the elimination of shock instability.
Influence of blade trailing edge profile on pressure pulsation in high-speed centrifugal pump
Authors: Cui Baoling , Chen Zhanyun , Zhang Yingbin
Published: June 2024

High-speed centrifugal pump can easily lead to severe pressure pulsation due to complex flow, seriously influencing the stable operation. The slant-cutting suction surface to the blade trailing edge midpoint is proposed to improve the fluid flow and dynamic–static interference at the blade outlet for the high-speed pump. Based on large eddy simulation method, the pressure pulsations in a high-speed centrifugal pump were comparatively analyzed under different blade edge profiles with slant-cutting angles of 15°, 30°, and 45°. The numerical performance curves for an OB high-speed centrifugal pump are basically consistent with the experimental ones. In addition, the heads and efficiencies for MB15, MB30, and MB45 pumps are all higher than those of the OB high-speed centrifugal pump under all working conditions, and the head increases to the maximum of 1.24% when the slant-cutting angle is 15°. The high-intensity pressure pulsation at the blade outlet is closely related to the shedding periodic vortex from the blade pressure surface and flow separation under high-speed conditions. Compared with the OB high-speed centrifugal pump, the pressure intensity is decreased by 3.92% and 4.07% at tongue area for MB15 and MB30 pumps, respectively.
Analyzing the thermal performance of transient heat transfer mechanism due to the combined effects of solar energy and variable surface temperature: Growing applications of solar energy in co-axial pipes
Authors: Bibi Bakhtawar , Ashraf Muhammad , Xinhua Wang , Ilyas Asifa , Rasool Ghulam , Sun Tao
Published: June 2024

The current analysis is carried out to study the laminar convective heat transfer characteristics that change with time in the co-axial pipes along the impact of heat radiation and variable surface temperature. The flow is assumed along the axial direction of the pipe, and variable boundary condition is assumed at the surface of the pipe due to the variable surface temperature. A two-dimensional mathematical model made up of non-linear partial differential equations is solved using the implicit finite difference method. The project involves predicting the thermal efficiency of a pipe's time dependent flow across a number of flow model-relevant parameter ranges. Graphical representations highlighted the derived predictions. After separating the numerical solutions into the time independent and the time dependent components, the time dependent energy and surface shearness were found using the data from the time independent component. Comprehensive detail of the obtained results for the non-dimensional parameters included in the flow formulation is predicted for steady state velocity, temperature distribution, time dependent surface sheerness, and time dependent energy sheerness, which is given in results and discussion section of the manuscript. Major focus is given on the influence of the radiation parameter on the above-mentioned primary measures. Furthermore, it is concluded that in all cases, the steady state flow is as R→∞ and velocity profile as U→1 and θ→0, which ensured the accuracy of the obtained results by satisfying the boundary conditions. For various values of the fluid's absorption parameter D = 1.0, 3.0, 5.0, and 10.0, the flow profile is increased and U→1 as R→∞. Simultaneously, thermal distribution also increases and θ→0 as R→∞.
Direct evidence of low work function on SrVO3 cathode using thermionic electron emission microscopy and high-field ultraviolet photoemission spectroscopy
Authors: Sheikh Md Sariful , Lin Lin , Jacobs Ryan , Kordesch Martin E. , Sadowski Jerzy T. , Charpentier Margaret , Morgan Dane , Booske John
Published: June 2024

Perovskite SrVO3 has recently been proposed as a novel electron emission cathode material. Density functional theory (DFT) calculations suggest multiple low work function surfaces, and recent experimental efforts have consistently demonstrated effective work functions of ∼2.7 eV for polycrystalline samples, both results suggesting, but not directly confirming, that some fraction of even lower work function surface is present. In this work, thermionic electron emission microscopy (ThEEM) and high-field ultraviolet photoemission spectroscopy (UPS) are used to study the local work function distribution and measure the work function of a partially oriented- (110)-SrVO3 perovskite oxide cathode surface. Our results show direct evidence of low work function patches of about 2.0 eV on the cathode surface, with a corresponding onset of observable thermionic emission at 750 °C. We hypothesize that, in our ThEEM and UPS experiments, the high applied electric field suppresses the patch field effect, enabling the direct measurement of local work functions. This measured work function of 2.0 eV is comparable to the previous DFT-calculated work function values of the SrVO-terminated (110) SrVO3 surface (2.3 eV) and SrO-terminated (100) surface (1.9 eV). The measured 2.0 eV value is also much lower than the work function for the (001) LaB6 single crystal cathode (∼2.7 eV) and comparable to the effective work function of B-type dispenser cathodes (∼2.1 eV). If SrVO3 thermionic emitters can be engineered to access domains of this low 2.0 eV work function, they have the potential to significantly improve thermionic emitter-based technologies.
Transient resonance of sloshing liquid with time-varying mass
Authors: Zhang Chongwei , Li Donghai , Xie Zhigang , Jin Heng , Ning Dezhi
Published: June 2024

This study examines the sloshing of liquid with time-varying mass in a tank. A set of innovative experiments is carried out involving a shaking table supporting a water tank equipped with a drain pipe. Physical evidence of transient resonance is observed for the first time. Transient resonance occurs under specific excitation conditions when the instantaneous average water level (AWL) approaches a critical depth. During transient resonance, the oscillatory amplitude of the free-surface elevation increases sharply and then decreases in an envelope pattern. A bifurcation of the frequency band is first found in the Morlet-wavelet time–frequency spectrum, coinciding with the appearance of the maximum oscillatory amplitude. How the excitation conditions, drainage rate, and initial water depth affect transient resonance is recognized. Two mathematical models—one based on linear modal theory and the other based on nonlinear asymptotic theory and the Bateman–Luke variational principle—are derived to replicate the physical observations, by which application scopes of both models have been greatly broadened. The linear solution fails to predict the key feature of transient resonance, namely, the asymmetric envelopes of the oscillatory component about the AWL. By contrast, the nonlinear asymptotic solution captures this asymmetric feature accurately, and predicts both the steady and maximum oscillatory amplitudes well. The nonlinear solution is decomposed into terms of order 1/3, 2/3, and 1 using an asymptotic series for component analyses. A special nonlinear jump behavior is observed. The effects of draining and filling on transient resonance are compared.
Origins of the unphysical noncovalent interaction energy curves obtained with the 2011 and 2012 Minnesota density functionals
Authors: Yu Feng
Published: June 2024

With the noncovalent interaction energy curves of the methane dimer [(CH4)2], we have clarified two different origins of the unphysical noncovalent interaction energy curves obtained with the Minnesota density functionals of M11-L, MN12-L, and MN12-SX. For the M11-L functional, the unphysical inflection point on the (CH4)2 interaction energy curve originates from the inclusion of the long-range exchange. As to the MN12-L and MN12-SX functionals, the lack of smoothness restraints results in unphysical inflection points on the corresponding (CH4)2 interaction energy curves. As a result, exchange functionals are as important as dispersion corrections for density functionals to map noncovalent interaction energy surfaces reasonably. Moreover, very highly parameterized functionals with smoothness restraints are suggested for investigating noncovalent interaction energy surfaces.
Evaluation of topological protection in kagome lattice-based thermal diffusion systems
Authors: Funayama K. , Hirotani J. , Tanaka H.
Published: June 2024

We evaluated topological protection for edge and higher-order corner states in topological diffusion systems based on the breathing kagome lattice. In the kagome lattice, the corner states appear at the corner boundary where all three Wannier centers in nontrivial unit cells are located. The three Wannier centers in a unit cell can be placed on the obtuse- and acute-corner boundaries utilizing the armchair boundary, generating topological acute- and obtuse-corner states. For another representative zigzag boundary, only the acute-corner unit cell has three Wannier centers located at the boundary; hence, only the acute-corner state appears. Our band analysis and numerical studies show that the topologically protected decay behavior for armchair boundaries is as robust as that for zigzag boundaries, unlike wave phenomena with space and time periodicities. Our findings can guide the flexible design of topological diffusion applications such as heat localization and recovery systems.
The role of mitochondria in sex- and age-specific gene expression in a species without sex chromosomes
Authors: Li Ning , Flanagan Ben A. , Edmands Suzanne
Published: June 2024

Mitochondria perform an array of functions, many of which involve interactions with gene products encoded by the nucleus. These mitochondrial functions, particularly those involving energy production, can be expected to differ between sexes and across ages. Here, we measured mitochondrial effects on sex- and age-specific gene expression in parental and reciprocal F1 hybrids between allopatric populations of
Tigriopus californicus
with over 20% mitochondrial DNA divergence. Because the species lacks sex chromosomes, sex-biased mitochondrial effects are not confounded by the effects of sex chromosomes. Results revealed pervasive sex differences in mitochondrial effects, including effects on energetics and aging involving nuclear interactions throughout the genome. Using single-individual RNA sequencing, sex differences were found to explain more than 80% of the variance in gene expression. Males had higher expression of mitochondrial genes and mitochondrially targeted proteins (MTPs) involved in oxidative phosphorylation (OXPHOS), while females had elevated expression of non-OXPHOS MTPs, indicating strongly sex-dimorphic energy metabolism at the whole organism level. Comparison of reciprocal F1 hybrids allowed insights into the nature of mito-nuclear interactions, showing both mitochondrial effects on nuclear expression, and nuclear effects on mitochondrial expression. While based on a small set of crosses, sex-specific increases in mitochondrial expression with age were associated with longer life. Network analyses identified nuclear components of strong mito-nuclear interactions and found them to be sexually dimorphic. These results highlight the profound impact of mitochondria and mito-nuclear interactions on sex- and age-specific gene expression.
Coxsackievirus A10 impairs nail regeneration and induces onychomadesis by mimicking DKK1 to attenuate Wnt signaling
Authors: Cui Yingzi , Shi Qiaoni , Song Pu , Tong Jianyu , Cheng Zhimin , Zhang Hangchuan , Wang Xiaodan , Zheng Yuxuan , Wu Yao , Wan Meng , Li Shihua , Zhao Xin , Tong Zhou , Yu Zhengquan , Gao Shan , Chen Ye-Guang , Gao George Fu
Published: June 2024

Coxsackievirus A10 (CV-A10) infection, a prominent cause of childhood hand-foot-and-mouth disease (HFMD), frequently manifests with the intriguing phenomenon of onychomadesis, characterized by nail shedding. However, the underlying mechanism is elusive. Here, we found that CV-A10 infection in mice could suppress Wnt/β-catenin signaling by restraining LDL receptor–related protein 6 (LRP6) phosphorylation and β-catenin accumulation and lead to onychomadesis. Mechanistically, CV-A10 mimics Dickkopf-related protein 1 (DKK1) to interact with Kringle-containing transmembrane protein 1 (KRM1), the CV-A10 cellular receptor. We further found that Wnt agonist (GSK3β inhibitor) CHIR99021 can restore nail stem cell differentiation and protect against nail shedding. These findings provide novel insights into the pathogenesis of CV-A10 and related viruses in onychomadesis and guide prognosis assessment and clinical treatment of the disease.
High performance Pt-anchored MoS2 based chemiresistive ascorbic acid sensor
Authors: Biswas Arpita , Kumar Ashok , Kumar Amit , Kwoka Monika , Bassi Gaurav , Kumar Mukesh , Kumar Mahesh
Published: June 2024

Ascorbic acid (AA), known as vitamin C, is a vital bioactive compound that plays a crucial role in several metabolic processes, including the synthesis of collagen and neurotransmitters, the removal of harmful free radicals, and the uptake of iron by cells in the human intestines. As a result, there is an absolute need for a highly selective, sensitive, and economically viable sensing platform for AA detection. Herein, we demonstrate a Pt-decorated MoS2 for efficient detection of an AA biosensor. MoS2 hollow rectangular structures were synthesized using an easy and inexpensive chemical vapor deposition approach to meet the increasing need for a reliable detection platform. The synthesized MoS2 hollow rectangular structures are characterized through field effect scanning electron microscopy (FESEM), energy-dispersive spectroscopy elemental mapping, Raman spectroscopy, and x-ray photoelectron spectroscopy. We fabricate a chemiresistive biosensor based on Pt-decorated MoS2 that measures AA with great precision and high sensitivity. The experiments were designed to evaluate the response of the Pt-decorated MoS2 biosensor in the presence and absence of AA, and selectivity was evaluated for a variety of biomolecules, and it was observed to be very selective towards AA. The Pt-MoS2 device had a higher response of 125% against 1 mM concentration of AA biomolecules, when compared to that of all other devices and 2.2 times higher than that of the pristine MoS2 device. The outcomes of this study demonstrate the efficacy of Pt-decorated MoS2 as a promising material for AA detection. This research contributes to the ongoing efforts to enhance our capabilities in monitoring and detecting AA, fostering advancements in environmental, biomedical, and industrial applications.
Spatially resolved optical emission analysis of spokes in HiPIMS utilising Al, Cr, Cu, Ti, and W targets
Authors: Hnilica J , Šlapanská M , Kroker M , Klein P , Vašina P
Published: June 2024

Investigating spokes in high-power impulse magnetron sputtering discharge requires non-invasive diagnostic methods to characterise accurately spoke properties. A fast photodiode and a cylindrical Langmuir probe were employed to synchronise the moment of acquisition of the optical emission spectrum with the position of a passing spoke. This study provides statistical data analysis to bring insights into spoke characteristics in a non-reactive argon atmosphere, employing aluminium, chromium, copper, titanium, and tungsten targets. Utilising different target materials, the objective is to describe basic parameters such as shape, length, and propagation velocity of spokes and also analyse spoke inner parameters such as floating potential and spectral emission, under nearly identical experimental conditions. From the optical emission, the most prominent species within the spoke were determined. Additionally, the mechanism governing spoke movement was described using a phenomenological model.
Recent progress and opportunities in 2D-material quantum dots: synthesis, doping, characterization, and applications
Authors: U Masuda , Sahu Swapnasagar , Tripathi Laxmi Narayan
Published: June 2024

The quantum dots derived from the 2D material are finding their applications in sustainable and emerging technologies due to their tunable properties by quantum confinement and scalable synthesis. Elemental doping in these quantum dots can enhance the performance favourably for the desired application. It can further tune the properties of parent counterparts leading to novel and interesting properties and applications. This review demonstrates the excellence of 2D materials-based quantum dots as a material platform. We critically analyzed and present a summary of the top-down and bottom-up synthesis of 2D material-derived quantum dots. Further, the doping of quantum dots and prominent characterization techniques to identify the successful incorporation of dopants in them are presented. In the end, we comprehensively analyzed the applications of these two-dimensional derived quantum dots in energy, optoelectronic, and quantum technological applications.
Cap like trajectories in 5D chaotic tangent hyperbolic memristive model: fractional calculus and encryption
Authors: Qureshi Muhammad Ali , Alam Khan Najeeb , Raza Salman , Iqbal Sheikh Muhammad Zeeshan
Published: June 2024

This research aims to investigate the influence of model parameters and fractional order on a novel mathematical model with tangent hyperbolic memristor. This investigation conducted by applying Lyapunov exponents and bifurcation analysis. We utilize the Lyapunov exponent theory to understand and characterize these chaotic behaviors under fractional indices. The Lyapunov exponent, bifurcation, and phase diagrams have been depicted to explore the intricate dynamics of the chaotic system governed by the chaotic equation. A novel approach termed Atangana-Baleanu-Caputo (ABC) fractional derivative (FD) to generate phase portraits and gain insights into the system’s behavior. The random numbers generated by the chaotic system are employed to distort the image through an amalgamated image encryption (AIE) algorithm. Subsequently, the integrity of the scrambled image has been assessed using various image security evaluation methods to reinforce the notion that combining the chaotic system and image can constitute a valuable encryption key. Finally, the chaotic model circuit realization uses active and passive components, and the outcomes are compared with the numerical simulations.
Study of charge transport in cesium lead bromide perovskite quantum dots and PCPDTBT composites: an application to photosensitive FETs
Authors: Shukla Preeti , Kumar Pankaj , Singh Anchal Kishore , Kumar Naresh , Kumar Lokendra
Published: June 2024

This work investigates the optical, structural, and photo-physical properties of PCPDTBT/cesium lead bromide (CsPbBr3) perovskite quantum dots (QDs) composite for optoelectronic devices. The composite was prepared by processing the PCPDTBT and CsPbBr3 QDs via the solution blending method. Incorporating CsPbBr3 QDs with different weight % (wt%) ratio in PCPDTBT influences its optoelectronic properties. UV–vis absorption spectroscopy, photoluminescence (PL), and atomic force microscopy measurements were used to analyze their optical and morphological properties. We observed that incorporating 4 wt% QDs in PCPDTBT enhanced its light absorption and charge transfer properties. Increased carrier lifetime for PCPDTBT/QDs (4 wt%) was observed from PL decay measurements. Further, we fabricated the field effect transistors (FETs) of pristine PCPDTBT and PCPDTBT/CsPbBr3 QDs composite (4 wt%) to study their electronic and charge transfer features. Significant variation in source-to-drain current (IDS) and carrier mobility has been observed. A substantial increased output current was observed for composite FET than pristine PCPDTBT-based FET due to charge transfer from QDs to PCPDTBT. Both PCPDTBT and PCPDTBT/CsPbBr3 QDs-based FET show enhanced current with illumination, which could be attributed to the photo-generated charge carriers.
Quasi-monoenergetic electron beam from LWFA: analytical approach
Authors: Starodubtseva E M , Tsymbalov I N , Gorlova D A , Ivanov K A , Savelev A B
Published: June 2024

Analytical dependence of the energy spread of electron beam on time and injection duration has been obtained with the 1D model of the quasi-linear laser wakefield electron acceleration, presented as phase portraits of electron energy relative to the plasma wave phase. The method for producing electron beams with variable energy and a lower energy spread compared to a standard bubble-like approach by transferring to a deaccelerating part with another phase trajectory (by reducing the plasma amplitude of a wave) has been developed. The analytically obtained results successfully describe key features of the previously obtained in Tsymbalov et al (2024 arXiv:2403.19828) experimental and numerical (PIC) data.
A cross-scenario and cross-subject domain adaptation method for driving fatigue detection
Authors: Luo Yun , Liu Wei , Li Hanqi , Lu Yong , Lu Bao-Liang
Published: June 2024

Objective. The scarcity of electroencephalogram (EEG) data, coupled with individual and scenario variations, leads to considerable challenges in real-world EEG-based driver fatigue detection. We propose a domain adaptation method that utilizes EEG data collected from a laboratory to supplement real-world EEG data and constructs a cross-scenario and cross-subject driver fatigue detection model for real-world scenarios. Approach. First, we collect EEG data from subjects participating in a driving experiment conducted in both laboratory and real-world scenarios. To address the issue of data scarcity, we build a real-world fatigued driving detection model by integrating the real-world data with the laboratory data. Then, we propose a method named cross-scenario and cross-subject domain adaptation (CS2DA), which aims to eliminate the domain shift problem caused by individual variances and scenario differences. Adversarial learning is adopted to extract the common features observed across different subjects within the same scenario. The multikernel maximum mean discrepancy (MK-MMD) method is applied to further minimize scenario differences. Additionally, we propose a conditional MK-MMD constraint to better utilize label information. Finally, we use seven rules to fuse the predicted labels. Main results. We evaluate the CS2DA method through extensive experiments conducted on the two EEG datasets created in this work: the SEED-VLA and the SEED-VRW datasets. Different domain adaptation methods are used to construct a real-world fatigued driving detection model using data from laboratory and real-world scenarios, as well as a combination of both. Our findings show that the proposed CS2DA method outperforms the existing traditional and adversarial learning-based domain adaptation approaches. We also find that combining data from both laboratory and real-world scenarios improves the performance of the model. Significance. This study contributes two EEG-based fatigue driving datasets and demonstrates that the proposed CS2DA method can effectively enhance the performance of a real-world fatigued driving detection model.
An extensive analysis of SOL properties in high-δ plasmas in ASDEX Upgrade
Authors: Redl A. , Eich T. , Vianello N. , Adamek J. , Bernert M. , Birkenmeier G. , Brida D. , David P. , Faitsch M. , Fischer R. , Grenfell G. , Ochoukov R. , Rohde V. , Tal B. , Dreval M. ,   the ASDEX Upgrade Team,   the EUROfusion Tokamak Exploitation Team
Published: June 2024

A set of dedicated H-mode discharges with constant heating power combining Neutral Beam Injection and Electron Cyclotron Resonance Heating have been executed at the ASDEX Upgrade tokamak using a high triangularity magnetic geometry in order to investigate the impact of filamentary transport to divertor and non-divertor components. The evolution of upstream scrape-off layer (SOL) profiles have been correlated with dedicated separatrix quantities, mostly with the turbulence control parameter

α

t

(Eich and Manz 2021 Nucl. Fusion
61 086016) describing the turbulence level at the separatrix. With increasing

α

t

, a broadening of the upstream density profiles in the near-SOL together with the formation of a density shoulder in the far-SOL have been observed. This phenomenon is associated with an enhanced filamentary transport dominating the radial turbulent transport in the far-SOL and confirmed by means of the cooling water calorimetry on non-divertor components. The probe measurements conducted with the ball-pen probe-head mounted on the midplane manipulator and a retarding-field analyzer close to the limiter surface indicate that the key mechanism increasing the radial filamentary transport to the first wall is an increase of the particle flux

Γ

r
,
fil

, caused primarily by the packing fraction

f

PF
,
fil

and the filament density

n

e
,
fil

. At the same time, the electron temperature

T

e

and ion temperature

T

i

measured close to the limiter surface show only small variations above

α

t

> 0.5. Both the filamentary heat flux and the gross erosion derived from the first wall probe measurements reach a magnitude that should be considered in the design of future fusion reactors.
Development of bilayer tissue-engineered scaffolds: combination of 3D printing and electrospinning methodologies
Authors: Yilmaz Hilal , Bedir Tuba , Gursoy Sevda , Kaya Elif , Senel Ilkay , Tinaz Gulgun Bosgelmez , Gunduz Oguzhan , Ustundag Cem Bulent
Published: June 2024

Although different fabrication methods and biomaterials are used in scaffold development, hydrogels and electrospun materials that provide the closest environment to the extracellular matrix have recently attracted considerable interest in tissue engineering applications. However, some of the limitations encountered in the application of these methods alone in scaffold fabrication have increased the tendency to use these methods together. In this study, a bilayer scaffold was developed using 3D-printed gelatin methacryloyl (GelMA) hydrogel containing ciprofloxacin (CIP) and electrospun polycaprolactone (PCL)-collagen (COL) patches. The bilayer scaffolds were characterized in terms of chemical, morphological, mechanical, swelling, and degradation properties; drug release, antibacterial properties, and cytocompatibility of the scaffolds were also studied. In conclusion, bilayer GelMA-CIP/PCL-COL scaffolds, which exhibit sufficient porosity, mechanical strength, and antibacterial properties and also support cell growth, are promising potential substitutes in tissue engineering applications.
Projected regional changes in mean and extreme precipitation over Africa in CMIP6 models
Authors: Bobde V , Akinsanola A A , Folorunsho A H , Adebiyi A A , Adeyeri O E
Published: June 2024

Precipitation plays a crucial role in Africa’s agriculture, water resources, and economic stability, and assessing its potential changes under future warming is important. In this study, we demonstrate that the latest generation of coupled climate models (CMIP6) robustly project substantial wetting over western, central, and eastern Africa. In contrast, southern Africa and Madagascar tend toward future drying. Under shared socioeconomic pathways (defined by Shared Socioeconomic Pathways SSP2-4.5 and SSP5-8.5), our results suggest that most parts of Africa, except for southern Africa and Madagascar, will experience very wet years five times more often in 2050–2100, according to the multi-model median. Conversely, southern Africa and Madagascar will experience very dry years twice as often by the end of the 21st century. Furthermore, we find that the increasing risk of extreme annual rainfall is accompanied by a shift toward days with heavier rainfall. Our findings provide important insights into inter-hemispheric changes in precipitation characteristics under future warming and underscore the need for serious mitigation and adaptation strategies.
Experimental investigation in enhancing the mechanical, wear and corrosion resistance properties of Al6061-SiC-NSA composites fabricated using stir casting process
Authors: S Dhanesh , Kumar K Senthil , P Tamil Selvam , Raghav G R
Published: June 2024

The study investigates the mechanical, and tribological properties of Al6061-SiC-NSA hybrid composites. The characterization via FE-SEM reveals NSA particle’s crystal structure and agglomeration, with an average particle size of approximately 400 nm. The EDS analysis confirms the presence of oxides (TiO2, SiO2, Fe2O3, Al2O3) along with calcium and potassium. The XRD spectra corroborate these findings, additionally identifying Calcite and intermetallic compounds. The Al6061–5SiC-10NSA composites has improved compressive strength of 254 MPa compared to 220 MPa for base Al6061 alloy. The tensile strength of base Al6061 (100 MPa) decreased to 70 MPa for Al6061–5SiC-20NSA composites. The tensile strength decreases with increasing NSA content. Fracture analysis indicates ductile fracture mechanisms, supported by FE-SEM images displaying honeycomb-like structures and dimples. Impact testing reveals reduced impact strength in composites compared to Al6061 (26J3), with Al6061–10SiC-5NSA exhibiting the best toughness of 22.5 J3. Density decreases in composites, with density of Al6061–5SiC-20NSA composites has reduced to 2.40 g cm−3. The microhardness of Al6061–10SiC-5NSA has better value of 109 HV, whereas further addition of NSA has resulted in decrease in microhardness of composites. Pin-on-disc wear tests demonstrate improved wear resistance with increased NSA content, with Al6061–5SiC-20NSA outperforming other compositions. COF decreases with increased NSA content and sliding speed. FE-SEM analysis of worn surfaces reveals that the major wear mechanism is adhesive wear followed by delamination, further the oxide formation along the surface aiding wear resistance of the composites. Tafel testing indicates decreased corrosion potential with increased NSA content, with Al6061–5SiC-20NSA exhibiting improved corrosion resistance.
Effect of power supply parameters on discharge characteristics and sterilization efficiency of magnetically driven rotating gliding arc
Authors: QIN 秦 Shaohua 绍华 , WANG 王 Meizhi 玫芝 , DU 杜 Jun 军 , NIE 聂 Lanlan 兰兰 , PAN 潘 Jie 杰
Published: June 2024

Plasma sterilization is a new generation of high-tech sterilization method that is fast, safe, and pollution free. It is widely used in medical, food, and environmental protection fields. Home air sterilization is an emerging field of plasma application, which puts higher requirements on the miniaturization, operational stability, and operating cost of plasma device. In this study, a novel magnetically driven rotating gliding arc (MDRGA) discharge device was used to sterilize Lactobacillus fermentation. Compared with the traditional gas-driven gliding arc, this device has a simple structure and a more stable gliding arc. Simulation using COMSOL Multiphysics showed that adding permanent magnets can form a stable magnetic field, which is conducive to the formation of gliding arcs. Experiments on the discharge performance, ozone concentration, and sterilization effect were conducted using different power supply parameters. The results revealed that the MDRGA process can be divided into three stages: starting, gliding, and extinguishing. Appropriate voltage was the key factor for stable arc gliding, and both high and low voltages were not conducive to stable arc gliding and ozone production. In this experimental setup, the sterilization effect was the best at 6.6 kV. A high modulation duty ratio was beneficial for achieving stable arc gliding. However, when the duty ratio exceeded a certain value, the improvement in the sterilization effect was slow. Therefore, considering the sterilization effect and energy factors comprehensively, we chose 80% as the optimal modulation duty ratio for this experimental device.
Loss of energetic particles due to feedback control of resistive wall mode in HL-3
Authors: ZHAO 赵 Yifei 弋菲 , LIU 刘 Yueqiang 钺强 , HAO 郝 Guangzhou 广周 , WANG 王 Zhengxiong 正汹 , DONG 董 Guanqi 冠崎 , WANG 王 Shuo 硕 , LI 李 Chunyu 春雨 , YANG 杨 Guanming 冠铭 , MIAO 苗 Yutian 雨田 , WANG 王 Yongqin 雍钦
Published: June 2024

Effects of three-dimensional (3D) magnetic field perturbations due to feedback control of an unstable

(

is toroidal mode number) resistive wall mode (RWM) on the energetic particle (EP) losses are systematically investigated for the HL-3 tokamak. The MARS-F (Liu et al 2000 Phys. Plasmas
7 3681) code, facilitated by the test particle guiding center tracing module REORBIT, is utilized for the study. The RWM is found to generally produce no EP loss for co-current particles in HL-3. Assuming the same perturbation level at the sensor location for the close-loop system, feedback produces nearly the same loss of counter-current EPs compared to the open-loop case. Assuming however that the sensor signal is ten times smaller in the close-loop system than the open-loop counter part (reflecting the fact that the RWM is more stable with feedback), the counter-current EP loss is found significantly reduced in the former. Most of EP losses occur only for particles launched close to the plasma edge, while particles launched further away from the plasma boundary experience much less loss. The strike points of lost EPs on the HL-3 limiting surface become more scattered for particles launched closer to the plasma boundary. Taking into account the full gyro-orbit of particles while approaching the limiting surface, REORBIT finds slightly enhanced loss fraction.
Electromigration and electrical sintering in printed silver from high current at room temperature
Authors: Jung Uidam , Wagner Ryan
Published: June 2024

Improved understanding of the reliability and failure physics of metal nanoparticle conductive inks would facilitate their large-scale deployment across a range of flexible electronics applications. We conduct room-temperature electromigration experiments on printed silver nanoparticle conductive ink test devices. We observe significant variation in failure time, location, and structure during these tests and during post-failure analysis with optical and electron microscopy. We use in situ Atomic Force Microscopy measurements to track volume changes in the sample as a function of time. These measurements provide additional data and understanding of the failure process within printed silver nanoparticle conductive inks.