bluuebunny/crossref_metadata_2025 huggingface dataset:
An explanation for the giant magnetoresistance in metal superlattices
Authors: Okulov V. I.
Published: January 2025

It is shown in the framework of the semiclassical kinetic theory that the effect of giant magnetoresistance can be observed in magnetic superlattices in the absence of penetration of conduction electrons through the boundaries between the layers.
Low-temperature magnetoresistance of quasi-two-dimensional conductors with a strong electron-phonon coupling
Authors: Kukushkin L. S. , Radchenko D. G. , Frentii A. V.
Published: January 2025

The magnetoresistance of a quasi-two-dimensional conductor in a strong transverse magnetic field is calculated by using the method developed by L. S. Kukushkin/Zh. Eksp. Teor. Fiz. 78, 1020 (1980)/. The scattering of carriers is mainly due to acoustic phonons, and the electron-phonon interaction is not assumed to be small. A power dependence of conductivity on temperature is calculated at low temperatures by taking two-phonon processes into account. The criteria for the applicability of the obtained results are described and systems in which these results can be realized are indicated.
On the theory of solidification of supercooled liquids. II: Kinetics of cluster-formation and competitive nucleation
Authors: Bakai A. S.
Published: January 2025

The kinetics of nucleation of noncrystalline solid clusters is studied by taking into account the diversity of structural states and the partial violation of ergodicity in the nucleus. A metric defining the spatial structure states is introduced on the set of structure states which, for a fixed number of atoms in the cluster, forms an ultrametric subspace so that the spatial structure states of a cluster are an aggregate of ultrametric spaces. The kinetics of structural transformations of clusters is described by the diffusion equation (which is an analog of the Zel’dovich equation) in this space. An expression is obtained for the rate of growth of clusters, and the definition of the kinetic vitrification temperature is introduced. The competing nucleation of crystallites and clusters in a molten metal is studied by way of an example.
Nonlinear intrinsic spin waves
Authors: Sukstanskii A. L. , Tarasenko S. V.
Published: January 2025

The existence of a new class of nonlinear magnetic excitations, viz., nonlinear intrinsic spin waves (intrinsic solitons) localized near the interface between two ferromagnets is predicted. The main parameters and the conditions of existence of these excitations are determined. It is shown that they have no linear analog.
Antiparamagnons and anomalies of the tunnel density of states in YBaCuO
Authors: Krivoruchko V. N. , Zubov E. E.
Published: January 2025

We consider changes of the spectra of single-particle excitations in superconducting CuO2 layers and in CuO chain layers, brought about by the mutual influence of superconducting pairing and magnetic fluctuations. The effect of two-dimensional antiferromagnetic fluctuations in the layers that contain the CuO chains on the tunnel characteristics of YBaCuO is considered. The calculated theoretical curves of the tunnel density of states demonstrate a qualitative agreement with experimental data.
Magnetic resonance properties and crystallization of the low-dimensional magnet [NH2(CH3)2]MnCl3·2H2O
Authors: Stepanov A. A. , Khatsko E. N. , Kobets M. I. , Pashchenko V. A. , Kaplienko A. I. , Chernyi A. S. , Mitkevich V. V. , Tret’yak S. M. , Kapustyanyk V. B.
Published: January 2025

The crystal structure of a single crystal of [NH2(CH3)2]MnCl3 · 2H2O is studied. It is shown that this compound belongs to the monoclinic system with a space group C2/c. The static magnetic susceptibility and magnetization are studied in the temperature range 0.7–300 K. A comparison with the theoretical models indicates the one-dimensional nature of the magnetic structure. The frequency field diagram of the AFMR spectrum is reconstructed at T=4.2 K, and the effective parameters of magnetic interactions are determined.
Investigation of the excitation spectrum of liquid 4He by inelastic neutron scattering technique
Authors: Bogoyavlenskii I. V. , Karnatsevich L. V. , Kolobrodov V. G. , Kozlov Zh. A. , Priezzhev V. B. , Puchkov A. V. , Skomorokhov A. N.
Published: January 2025

It is found that the one-particle excitation spectrum of liquid 4He has a complex multicomponent structure. Two components of the peak of slow neutron scattering are observed in the phonon part of the normal phase of liquid helium: the narrow component (s) and the wide component (w). The maxon-roton spectral region contains only the wide component w. In the superfluid phase of liquid helium, one more narrow scattering component (n) is added to the maxon-roton part of the spectrum, the intensity of this component increasing sharply upon a decrease in temperature. On the other hand, the intensity of the wide component drops rapidly. Therefore, the structure of the excitation spectrum undergoes significant changes upon a transition from the normal to the superfluid phase, as well as in both phases upon a transition from phonon to maxons. The obtained results are in qualitative agreement with the model of excitation spectrum of liquid 4He, which has been proposed in recent years by Griffin, Glyde, and Stirling. However, some of the details of the observed pattern cannot be explained by using prevailing concepts.
Kapitza’s pendulum and the problem of second-order phase transitions
Authors: Antsygina T. N. , Slyusarev V. A.
Published: January 2025

The renormalization group equations of the fluctuation theory of phase transitions are obtained by using the methods of nonlinear mechanics.
Kapitza’s law in the magnetoresistance of metals
Authors: Peschanskii V. G.
Published: January 2025

A brief history is given of the discovery of Kapitza’s law. Attempts at a theoretical interpretation of the linear increase in the electrical resistance of metals with increase in the magnetic field, discovered experimentally by Kapitza, are discussed.
Detection and investigation of the properties of circular vortex rings in current-carrying type II superconductors Bi1.6Pb0.4Sr2Ca2Cu3Oy
Authors: Khirnyi V. F. , Seminozhenko V. P. , Kozlovskii A. A. , Grinchenko Yu. A.
Published: January 2025

The evolution of electromagnetic processes with time in an isolated rod of Bi1.6Pb0.4Sr2Ca2Cu3Oy ceramic (type II superconductor) carrying a transport current I is studied. The intrinsic magnetic field H of the current is higher than the lower critical field Hc1. For H>Hc1, circular closed Josephson vortex rings are formed on the surface of the HTS sample. The dynamics of their formation and movement leading to their exit from the sample due to broadening is studied for the first time. For this purpose, the variation of the signal χ’(T,t,I) with time t after switching off the current I is studied. It is found that thanks to their long lifetime, the signal χ’(T,t,I) remains unchanged for tens of seconds.
Variation of the superconducting transition temperature in metal oxides YBa2Cu3O7–δ upon substitution of paramagnetic impurities for copper ions
Authors: Kosov A. A.
Published: January 2025

A nonphonon mechanism of superconductivity is worked out, which can be used to describe the behavior of the superconducting transition temperature of YBa2(Cu1–x Mx)3O7–δ compounds (M = Mn, Zn, etc.) depending on the atomic concentration x and the oxygen index 7–δ. The effect of paramagnetic impurities substituted for copper ions in CuO2 planes of yttrium ceramics on the superconducting transition temperature is analyzed.
Kinetic properties of superconductors with a strong inelastic scattering of quasiparticles
Authors: Voitenko A. I. , Gabovich A. M.
Published: January 2025

Kinetic characteristics of superconductors (the ultrasound absorption αs by electrons, the electron thermal conductivity κes, and nuclear spin-lattice relaxation rate Rs) normalized to corresponding values in the normal state are calculated by using a model describing the influence of inelastic scattering of electrons on the temperature-dependent superconducting order parameter Δ. The values of αs and κes decrease sharply with temperature near the critical temperature Tc . For low intensities of inelastic scattering, Rs depends on T nonmonotonically with a peak near Tc. As the scattering amplitude increases, the functions Rs(T) decrease monotonically with T. The results are compared with experimental data for HTS oxides.
Local self-heating of flux bundle during its motion
Authors: Shklovskij V. A.
Published: January 2025

Stimulated by recent experiments we have calculated and analyzed the self-heating temperature field of a moving flux bundle (FB) of radius R in bulk superconductor with temperature dependent heat capacity and thermal conductivity. The value of average temperature of the FB is obtained as a function of its mean velocity. These results are used for a discussion of those effects which are sensitive to unavoidable intrinsic local overheating of FBs; they are especially important in the cases where “overall” self-heating of the sample is negligible. The typical values of possible overheating of FBs at low ambient temperature are estimated for several La-, Y- and Bi-based superconductors.
Theory of electron quantum transport through arbitrary 2D structures connected by a wire
Authors: Klimenko Yu. A. , Onipko A. I.
Published: January 2025

An exact formal solution of the scattering problem for the case of two arbitrary 2D structures is obtained for the first time in terms of the extended S-matrices of the constituents. It is shown that the formalism developed here can be used effectively for investigating transport and spectral characteristics of quantum systems with a complex geometry. Among other things, a nonlinear variation of the number of resonances in the transmission spectrum of a conductor with a double right-angle bend upon an increase in the distance between the bends is predicted. When applied for describing the conductivity of a conductor with a constriction, the theory leads to an analytic expression which reproduces almost exactly the behavior of conductivity as a function of the Fermi energy for any parameters of the system.
Variation of resistivity and deforming stress of zirconium under active deformation at 4.2 K
Authors: Nikiforenko V. N. , Lavrent’ev F. F. , Lukac P. , Trojanova Z.
Published: January 2025

The structural state of zirconium polycrystals deformed by stretching at 4.2 K is investigated by resistometric and transmission electron microscopic (TEM) methods. It is shown that, under active deformation at low temperatures, the main contribution to resistivity near the yield stress σc is associated above all with an increase in the density of prismatic dislocations. The regularities in the evolution of dislocation structure ensuring deformation strengthening near σc of zirconium are mainly due to an increase in the dipole density and due to the interaction between prismatic dislocation pile-ups.
Peculiarities of the statics and dynamics of magnetic insulators with single-ion anisotropy
Authors: Loktev V. M. , Ostrovskii V. S.
Published: January 2025

We generalize results of the static and dynamic investigations on ferro- and antiferro-ordered magnetic insulators whose anisotropy is brought about by a strong spin-orbit coupling contribution. An attempt is made to substitute the following assertion: magnetic materials of the above type constitutes a special class, for which the basic restriction of the quasielastics, viz., the conservation of the spin modulus, experiences a substantial violation. We consider qualitatively different cases of strong and weak single-ion anisotropy for different magnetic symmetry types, zero and finite temperatures, longitudinal and transverse magnetic fields. Questions of the nonlinear dynamics of such magnetic materials and some peculiarities of their optical properties are touched upon.
Magnetic properties and structure of the quasi-two-dimensional Ising magnet CsEr(MoO4)2
Authors: Khatsko E. N. , Chernyi A. S. , Kobets M. I. , Pashchenko V. A. , Kaplienko A. I. , Gurskas A. A. , Mitkevich V. V. , Tret’yak S. M.
Published: January 2025

Single crystals of CsEr(MoO4)2 are obtained, their x-ray structural investigations are carried out, and the symmetry group and lattice parameters are determined. The EPR spectral investigations reveal the presence of a paramagnetic Er3+ center with a highly anisotropic, practically Ising-like g-tensor (ga′ = 0.42, gb = 19.2, gc = 1.45). The data of temperature dependences of the magnetic susceptibility of the CsEr(MoO4)2 single crystal reveal a phase transition to the antiferromagnetic state at Tc = 0.84 K. A first-order metamagnetic transition caused by crystallographic anisotropy and competing exchanges is observed in the magnetically ordered state. Above Tc, short-range order effects are observed right up to helium temperatures. Dipole–dipole energy calculations for possible magnetic structures show that the dipole–dipole interaction leads to ferromagnetic ordering in randomly-connected chains at temperatures considerably higher than Tc. It is shown that a three-dimensional collinear magnetic structure of ferromagnetic Ising chains with antiferromagnetic interaction between chains is realized during the magnetic phase transition. The temperature dependences of susceptibility are described quite well in the model of weakly interacting ferromagnetic Ising chains.
Analysis of electron-topological transition in superconducting alloys Mo–Re and Mo–Re–Nb
Authors: Ignat’eva T. A. , Gann V. V. , Velikodnyi A. N.
Published: January 2025

The dependences of Tc and dTc/dP on the concentration of Re and Nb impurities in Mo–Re and Mo–Re–Nb alloys are investigated experimentally and theoretically. The peak on the dTc/dP vs c dependence is attributed to an electron-topological transition (ETT) in these alloys. The equation proposed for the superconducting transition temperature in the presence of an ETT makes it possible to describe considerable changes in Tc of Mo under the action of impurities. The values of parameters characterizing the ETT in the systems under investigation are determined. It is shown that the ETT is responsible for the formation of a new electron group in the Mo–Re system under the effect of the Re impurity and its destruction in the Mo–Re–Nb system under the effect of the Nb impurity.
Quantum corrections to the temperature dependence of the conductivity of bismuth films in a strong electric field. 1. Localization correction
Authors: Kashirin V. Yu. , Komnik Yu. F.
Published: January 2025

The temperature variation of quantum correction to the conductivity of thin (∼100 Å) Bi films, associated with weak localization of electrons under conditions of electron overheating, is studied. It is found that the localization correction decreases in strong currents due to an increase in the electron temperature. No direct effect of the electric field E on the localization correction is observed (at least in fields E ≲ 20 V · cm−1). It is found that, for electron overheating described by two different temperatures Te (electron) and Tph (phonons), the electron temperature has a decisive influence on the localization correction under these conditions.
Quantum corrections to the temperature dependence of conductivity of Bi films in a strong electric field. II. Coulomb correction
Authors: Komnik Yu. F. , Kashirin V. Yu.
Published: January 2025

Temperature dependence of the quantum correction to the conductivity of thin (∼100 Å) Bi films, which is associated with the enhancement of the electron–electron interaction (Coulomb correction), is investigated under the effect of electron overheating. It is found that, in the case of a strong current, the Coulomb correction decreases as a result of an increase in the electron temperature, but this is not the only reason behind this effect. The influence of a change in the interaction between electrons due to the drift of charge carriers in the electric field is also observed. This effect is discussed together with a change in the contribution of quantum corrections to the magnetoresistance of thin Bi films under the influence of the electric fields [V. Yu. Kashirin and Yu. F. Komnik, Fiz. Nizk. Temp. 19, 165 (1993); Sov. J. Low Temp. Phys. 19, 117 (1993)].
Small-radius precession solitons and their contribution to the response functions of two-dimensional magnets
Authors: Kolezhuk A. K. , Filin D. V.
Published: January 2025

The contribution of precession topological solitons to the dynamic structural factor (DSF) of two-dimensional easy-axis ferro- and antiferromagnets is calculated taking into account spatial diffusion of soliton parameters (velocity and precession frequency). It is shown that precession significantly changes the shape of the central soliton peak in transverse DSF components.
Phylogenetic position of the subfamily Symphrasinae (Insecta: Neuroptera), its intergeneric relationships and evolution of the raptorial condition within Mantispoidea
Authors: Ardila-Camacho Adrian , Contreras-Ramos Atilano
Published: January 2025

The superfamily Mantispoidea (Insecta: Neuroptera) includes the families Berothidae, Rhachiberothidae and Mantispidae. Among these taxa, the last two are collectively known as Raptorial Mantispoidea due to the presence of grasping forelegs for predatory habits. The Mantispidae classically included the subfamilies Symphrasinae, Drepanicinae, Calomantispinae and Mantispinae, yet recent research challenged this classification scheme as well as the monophyly of this family resulting in Symphrasinae being transferred to Rhachiberothidae. The phylogenetic position of the subfamily Symphrasinae within Mantispoidea is here inferred based on total evidence analysis combining three genes (COI, 16S and 18S) and 72 morphological characters scored from living representatives of all Mantispidae subfamilies (12 genera), the 3 genera of Symphrasinae, and Rhachiberothinae (1 genus). Representatives of Berothidae (four genera) and Hemerobiidae (one genus) were used as outgroup taxa. Results of the total evidence analysis were compared with parsimony and maximum likelihood analyses of the morphological and molecular datasets of the COI, 16S and 18S genes. The resultant phylogeny under total evidence recovered Rhachiberothidae as a monophyletic group with strong support in which Symphrasinae was found as sister to Rhachiberothinae. The three genera contained in Symphrasinae, i.e. Anchieta, Plega and Trichoscelia were each recovered as monophyletic in the parsimony analysis, with Anchieta as sister to Trichoscelia + Plega. The family Mantispidae was also recovered as monophyletic and sister to Rhachiberothidae, with Mantispinae as sister to Calomantispinae + Drepanicinae. Evolution of the raptorial condition in Mantispoidea is discussed based on the performed analyses. The morphology and the structure of the raptorial foreleg and the prothorax (i.e. the raptorial system) support the close relationship of Symphrasinae with Rhachiberothinae rather than to other Mantispidae subfamilies which possess a distinctive and well-differentiated raptorial apparatus. The Rhachiberothidae (including Symphrasinae) are distinguished by the presence of a foretarsal Stitz organ. Furthermore, a sit-and-wait predatory strategy is hypothesised for this taxon, whereas the Mantispidae are likely sophisticated active-ambushing predators.
Estimating feral cat (Felis catus) population density in eastern Australia’s subtropical rainforest using spatial capture-recapture incorporating unidentified individuals
Authors: McHugh Darren , Hollanders Matthijs , Legge Sarah , Augustine Ben C.
Published: January 2025

Context Management of broadly distributed invasive species requires knowledge of population densities across multiple ecosystems. The feral cat (Felis catus) has a continental distribution in Australia and has caused many declines and extinctions; however, density estimates from several ecosystems are few or lacking. Camera trapping data coupled with spatially explicit capture–recapture analysis is a suitable approach for estimating cat densities. However, if a large portion of individuals cannot be identified, density estimation may be difficult and estimates may be too low. Aims We aimed to estimate the feral cat density and population size within the subtropical Gondwanan Rainforest of eastern Australia, an area with world heritage status and high biodiversity values, and in which cat density was not known. Methods We used feral cat data from a grid of 60 camera traps deployed over 305 days in Border Ranges National Park, totalling 18,300 camera trapping nights. We employed a ‘random thinning’ spatially explicit capture–recapture model that considered detections of both known and unknown feral cat identities. Our modelling included a primary detection history of identified individuals and a secondary detection history that included pelage type, which allowed us to account for individuals with homogeneous pelage types. Key results Feral cat density was estimated at 0.858 cats km−2 (95% HPDI 0.432, 1.385), which is much higher than the average feral cat density across the Australian continent of 0.27 cats km−2 (95% CI: 0.18–0.45). The probability of identifying unique individuals was low for black and tabby cats compared with other pelage types. Population sizes during the four survey periods were estimated to be similar, with posterior medians ranging from 197 to 202 individuals and 95% highest posterior density intervals ranging from 95 to 329 individuals within a ~234 km2 area. Conclusions Our study provides the first robust feral cat density estimate from a subtropical rainforest ecosystem. Implications Our results add to a growing body of literature that suggests feral cat densities are high in productive mesic reserves of eastern Australia. Management of feral cats in Gondwanan World Heritage Areas should be prioritised to limit impacts on narrow-range endemic species that are likely prey to feral cats.
Elliptic Flow Differences between Baryons and Anti-Baryons in Heavy-Ion Collisions Using SMASH Model
Authors: Zhou Shuai , Shi Shusu
Published: January 2025

Significant differences exist in the elliptic flow v
2 for particles and their corresponding anti-particles. These differences, which are more significant for baryons and anti-baryons, were observed from the solenoidal tracker (STAR) experiment during Beam Energy Scan I (BES-I) at relativistic heavy ion collider (RHIC). By employing the simulated many-accelerated strongly interacting hadrons (SMASH) model, we studied the v
2 differences between protons and anti-protons as well as between Λ and

Λ
¯

in Au + Au collisions at

s

NN

=
7.7

GeV as a function of the evolution time. It was found that as the evolution time increases, the v
2 differences between protons and anti-protons become more significant than those between Λ and

Λ
¯

. This phenomenon can be explained by the different constituent quarks of protons and Λ. Given that some of the u and d quarks come from the colliding nuclei and are transported to midrapidity, they undergo more interactions than the produced quarks, resulting in protons Δv
2 being larger than Λ Δv
2. We compared the SMASH calculations with STAR BES-I data and concluded that higher-precision data from BES-II will set constraints on theoretical frameworks to interpret the v
2 differences between particles and anti-particles.
The effect of rapid thermal annealing on 1.55 μm InAs/InP quantum dots
Authors: Dear Calum , Park Jae-Seong , Jia Hui , EL HAJRAOUI Khalil , Yuan Jiajing , Wang Yangqian , Hou Yaonan , Deng Huiwen , Li Qiang , Ramasse Quentin , Seeds Alwyn , Tang Mingchu , Liu Huiyun
Published: January 2025

Rapid thermal annealing (RTA) can be used as a post-growth method to adjust the optical properties of III-V materials. This work investigates the efficacy of applying cyclic RTA to 1.55 μm multi-layer InAs/InAlGaAs quantum dots (QDs) grown on (001) InP substrate by molecular beam epitaxy. Samples cyclically-annealed at 600 °C retain most of their as-grown optical, structural, and compositional characteristics whilst exhibiting a 4.6-fold increase in peak PL intensity. This strategy was successfully implemented in broad-area devices with improved slope efficiency and output power, demonstrating cyclic RTA as an effective method in enhancing high-performance 1.55 μm QD lasers on InP (001) substrates.
Lattice thermal conductivity in CrSBr: the effects of interlayer interaction, magnetic ordering and external strain
Authors: Liu Ying , Zhi Yupeng , Liu Qinxi , Liu Yinqiao , Jiang Xue , Zhao Jijun
Published: January 2025

With the continuous development of digital information and big data technologies, the ambient temperature and heat generation during the operation of magnetic storage devices play an increasingly crucial role in ensuring data security and device stability. In this study, we conducted a thorough investigation on in-plane lattice thermal conductivity of the van der Waals (vdWs) magnetic semiconductor CrSBr from bulk to monolayer using first-principles calculations and phonon Boltzmann transport equation. Our findings indicated that CrSBr show strong anisotropic thermal transport behaviors and layer number and magnetic ordering dependent lattice thermal conductivity. The lowest thermal conductivity is observed in y direction of antiferromagnetic CrSBr bilayer at all temperatures. Through the analysis of phonon spectra, phonon lifetime, heat capacity, scattering probability, phonon–phonon interaction strength, we demonstrated that out of plane acoustic phonon modes soften, the shift of Cr–Br antisymmetrical stretching vibrations, and large phonon band gap are the main factors. These results offer a comprehensive insight into phonon transport phenomena in vdWs magnetic materials.
Multi-performance index reinforcement learning training of beaver-like robot
Authors: Chen Gang , Xue Hanhan , Meng Xianghui , Zhao Zhihan , Liu Zhen
Published: January 2025

The underwater environment is characterized by its inherent complexity and dynamics, leading to substantial interference with the precision of underwater measurement data. To enhance the precision of underwater data measurements, underwater robotic platforms necessitate improved motion and stability characteristics. As amphibian mammals, beavers possess excellent amphibious abilities and a wide range of environmental adaptability. Based on the observation of biological morphology and hind limb fin structure of beavers, this study analyses their swimming mechanism and designs a beaver-like robot. This study introduces an efficient control algorithm designed for a beaver-like robot platform. The algorithm integrates reinforcement learning with conservative Q-learning, model-based policy optimization and deep Q-network methods to facilitate offline training of the robot. A training weight allocation system is employed to enhance adaptability across diverse swimming conditions in the complex underwater setting. Simulating the robot’s underwater environment, the algorithm has demonstrated effective training in both speed and stability. The pitch angle is successfully stabilized between −0.245 and 0.305 rad, while the robot’s speed reaches up to 0.38 m·s−1.
An enhanced dung beetle optimizer with adaptive node selection and dynamic step search for mobile robots path planning
Authors: Zhang Wanying , Zhang Huajun , Zhang Xuetao
Published: January 2025

Path planning plays a crucial role in determining the shortest and safest route for autonomous mobile robots, and metaheuristic optimization algorithms have demonstrated their efficacy in solving complex problems involving numerous and variably shaped obstacles. The dung beetle optimizer (DBO) emerges as a novel heuristic optimization algorithm, drawing inspiration from the behavior patterns exhibited by dung beetles. This paper presents an improved algorithm called the enhanced DBO (EDBO) designed to address the mobile robot path planning problem. First, a node selection strategy based on the search radius is proposed to reduce the probability of path reciprocation while concurrently enhancing the initial population quality. Second, the conventional ball-rolling strategy employed in DBO is replaced with a dynamic step size search strategy. This strategy dynamically adjusts the step size based on the relative distance between the current position and the worst position of each iteration, enabling the population to update its position adaptively in response to environmental changes. Additionally, the global optimal position is incorporated to guide the search process, thereby improving the global search performance of DBO. Finally, a path fine-tuning strategy is implemented to refine the new generated individuals, with geometric principles of triangles being introduced to locally adjust the optimized path and guide the population out of local optima. Experiments are conducted to validate the effectiveness of the three improvement strategies, comparing the path optimization performance of EDBO with five other algorithms across five different complexity environments. Additionally, two statistical testing methods are employed to evaluate the experimental results. The experimental results indicate that, in all five environments, EDBO outperforms the other five algorithms in terms of path length and achieves superior path smoothness in 80% of the cases. Moreover, EDBO consistently demonstrates better overall performance than DBO, excelling in both convergence accuracy and speed.
Design and development of magnetic flexible endoscope for upper gastrointestinal examination
Authors: Wang Zili , Weng Ding , Li Zhaoxin , Chen Lei , Ma Yuan , Wang Jiadao
Published: January 2025

Magnetic continuum robot (CR) represents a subtype of CRs, which could realize non-contact manipulation through external magnetic field. Their appearance alongside advancements in robotic technology has significantly improved procedures such as flexible endoscopy examinations, microscopic surgeries, and active catheter operations, providing new ideas and approaches for endoscope examination. By using magnetic field, observation and navigation at different positions are achieved by controlling the bending of the flexible endoscope tip through magnetic torque. In this study a design and fabrication approach for miniaturized magnetic flexible endoscope (diameter of 4 mm) was proposed hoping to achieve the functionality of upper gastrointestinal endoscopy. Experimental validation on a 3D electromagnetic platform underscores the flexibility and steerability of the magnetic flexible endoscope, with a mean-square error of 16.52° for maximum bending angle. Additionally, integrating simulation results based on minimum potential energy principle of magnetic potential energy and elastic potential energy has demonstrated precise deformation forecasting, compared with experimental results. The results also indicated that the maximum deflection angle of the magnetic flexible endoscope can reach 164.97°. Magnetic fields in different directions are obtained by varying the current of the power sources. The magnetic flexible endoscope can achieve trajectory motion within a 2D plane along predefined paths. The functionality of the magnetic flexible endoscope has been demonstrated by in vitro model and ex vivo porcine stomach experiments, which showed that magnetic flexible endoscope can bend and deform within the model to observe different positions and even realize the retroflexion capabilities of existing endoscopes. These findings provide a foundation for further development of miniaturized magnetic flexible endoscopic manipulation devices, aiming to improve treatment efficacy and optimize patient treatment experiences.
Topology-optimized flexible capacitive pressure sensors suitable for medium-pressure range
Authors: Xia Cheng , Li Jiachun , Chen Yuewei , Zou Zhongfei , Zhang Yingbo , Shi Wenhai , Wang Yongtao
Published: January 2025

Numerous flexible capacitive pressure sensors (FCPSs) designed for low-pressure range perform highly sensitive sensing over a wide detection range. However, these sensors are primarily based on inspiration, and large pressure applications have yet to be explored. In this paper, we propose for the first time the stiffness topology optimization of hyperelastic dielectrics by analyzing the working mechanism and target sensing characteristics. The feasibility of using topological dielectric as a dielectric layer for FCPSs is evaluated through a combined analysis using ABAQUS and COMSOL. Three different volume fractions (

f

∗

) FCPSs (

f

∗

= 0.35,0.4,0.5) are manufactured utilizing 3D printing. The FCPSs exhibited high sensitivity at external pressure values of 7.06 kPa (

f

∗

= 0.35), 8.71 kPa (

f

∗

= 0.4), and 18.9 kPa (

f

∗

= 0.5), respectively, and the highest sensitivity reached 1.29 kPa−1 (

f

∗

= 0.35). In addition, when

f

∗

= 0.35, FCPSs exhibiting high repeatability over 6000 cycles in 40 kPa, a relatively wide detection range (60 kPa) and high stability at different pressures (5–60 kPa) and temperatures (15 °C–60 °C). Lastly, the high performance of FCPSs is further illustrated through motion monitoring of three different joints, collision monitoring of a 3D printer, and testing on a robotic car, indicating their application prospects.
Design of a dissipative chaotic system based on Hamiltonian energy function and its application
Authors: Xue Rui , Ma Yangqin , An Xinlei , Xiong Li , Zhang Jiangang
Published: January 2025

The construction and enhancement of chaotic systems are the research hotspot, especially in the secure communication applications fields. By applying Hamiltonian energy function to differential dynamical system, a dissipative nonlinear system is constructed based on generalized Hamiltonian system and Hamiltonian energy function, which enlarge the range of chaos system construction. The dynamical behavior of the new system is analyzed using bifurcation diagrams, maximum Lyapunov exponent diagrams and phase diagrams. It is shown that the system can produce an extensive range of continuous chaos by modulating the input parameters of external energy. At the same time, various attractors are found with the evolution of different initial values, that is the phenomenon known as ‘multi stability’, which has more advantage in image encryption. Due to high spectral entropy complexity of the chaotic sequences generated from the dissipative system, the practical application in image encryption is investigated. Considering the demand of efficient image transmission, a multi-image encryption algorithm is proposed based on DNA encoding operation. The algorithm is mainly composed of the following parts: image reconstruction, cross-plane scrambling and DNA diffusion. Eventually, the security analysis results reveal that the encryption algorithm can encrypt numrous color images of different sizes at once, and better security performance can be verified. By combining energy transfer and dissipation with the folding and contraction of trajectories in chaotic motion, a new chaotic system is constructed through energy distribution. This construction method has a deep physical background and is easy to understand the chaotic phenomenon, which has great potential engineering application value.
Broadband low-frequency bandgap in the elastic metamaterial under load conditions
Authors: Zhou Xuewen , Zeng Yi , Zhang Kun , Yang Zhen , Zhao Xiangwei , Xie Zhenzhen , He Chuanchuan
Published: January 2025

In the past two decades, metamaterials have captivated scientists worldwide due to their unique bandgap characteristics, which have been extensively validated through numerous numerical simulations and experiments. This study presents a novel elastic metamaterial designed to function under load conditions. The band structure was computed using finite element method (FEM) software, revealing a bandgap frequency range from 440 Hz to 2880 Hz, with a relative bandwidth of approximately 1.47. Experimental results from shaking table tests, alongside numerical simulations, have demonstrated the attenuation capabilities of the elastic metamaterial when subjected to a 40 kg load. This research not only offers a promising approach to controlling elastic waves but also introduces innovative design concepts for vibration isolation under load.
Propagation of envelope solitons in the presence of generalized (r; q) distribution of electrons
Authors: Akhtar N , Hussain S
Published: January 2025

The study has been made for modulational instability of ion acoustic waves in an electron-ion unmagnetized plasma where ions are dynamic and warm while electrons follows the generalized (r, q) distribution. The Krylov Bogoliubov Mitropolsky (KBM) method is employed to derive the nonlinear Schrödinger equation (NLSE). The dispersive and nonlinear coefficients P and Q are retrieved which depend onσ

i
(Temperature ratio) and spectral indices

r
,
q

.

The bright and dark solitons are excited for the case PQ > 0 and PQ < 0 respectively. Amplitude of bright solitons is characterized by a localized intensity peak and dark solitons by a localized intensity hole on a homogeneous background. The growth rates and modulationally stable/unstable zones are analyzed numerically. It is established that spectral indices (r, q) of electron distribution function and temperature ratio of ion to electron play a major role in the creation of bright/dark envelope solitons in electron-ion plasmas in the presence of nonthermal distribution.
Characterization of the crosstalk properties of image intensifier spot energy
Authors: Xu Shihao , Bai Yonglin , Li Ran , Cao Weiwei , Shi Dalian , Lv Linwei , Liang Xiaozhen , Gao Jiarui
Published: January 2025

In the field of high-energy particle detection, Intensified scientific CMOS (IsCMOS) cameras, which utilize image intensifier coupling, can enhance the input spot, generate a grey-value image of the improved spot, and subsequently reconstruct the crystal deposition energy based on the grey value. The image intensifier, playing a critical role in the crosstalk energy calibration of the spot, is a crucial component of the detector enhancement camera. Reducing the crosstalk of the spot output by the image intensifier contributes to the subsequent accurate calibration of high-energy cosmic ray energy. We have designed a test bed to quantify the spot energy crosstalk from Wavelength Shifting Fibers (WLSF) and conducted an in-depth analysis of the spot energy crosstalk in image intensifiers with varying MCP structures. The results indicate that the spot energy crosstalk is higher for weak signals and that increasing the MIP value of the input signal cannot effectively reduce the spot energy crosstalk when the spot is saturated. Nevertheless, when the spot is not saturated, the spot energy crosstalk can be effectively reduced by increasing the operating voltage of the MCP. Furthermore, reducing the aspect ratio of the MCP and increasing the opening area ratio can also mitigate the spot energy crosstalk in the image intensifier.
Foundational guidelines for enhancing neurotechnology research and development through end-user involvement
Authors: Güemes Amparo , Costa Tiago da Silva , Makin Tamar R
Published: January 2025

Neurotechnologies are increasingly becoming integrated with our everyday lives, our bodies and our mental states. As the popularity and impact of neurotechnology grows, so does our responsibility to ensure we understand its particular implications on its end users, as well as broader ethical and societal implications. There are many different terms and frameworks to articulate the concept of involving end users in the technology development lifecycle, for example: ‘Public and Patient Involvement and Engagement’ (PPIE), ‘lived experience’, ‘co-design’ or ‘co-production’. The objective of this tutorial is to utilise the PPIE framework to develop clear guidelines for implementing a robust involvement process of current and future end-users in neurotechnology, with emphasis on patient involvement.
After an introduction that coveys the tangible and conceptual benefits of user involvement, we first guide the reader to develop a general strategy towards setting up their own PPIE process. We then help the reader map out their relevant stakeholders and provide advice on how to consider user diversity and representation. We also provide advice and tools on how to quantify the outcomes of the engagement.
We consolidate advice from various online sources to orient individual teams (and their funders) to carve up their own approach to meaningful involvement. Key outputs include a stakeholder mapping tool, methods to measure the impact of engagement, and a structured checklist for transparent reporting.
Enabling end-users and other stakeholders to participate in the development of neurotechnology, even at its earliest stages of conception, will help us better navigate our design around ethical, social, and usability considerations, and deliver more impactful technologies. The overall aim is the establishment of gold-standard methodologies for ensuring that patient and public insights are at the forefront of our scientific inquiry and product development.
Tropical montane forest loss dominated by increased 1–10 hectare-sized patches
Authors: He Xinyue , Spracklen Dominick V , Holden Joseph , Zeng Zhenzhong
Published: January 2025

Tropical forest loss continues across mountain regions at alarming rates, threatening biodiversity, carbon storage and ecosystem sustainability. To improve our understanding of the dynamics of tropical mountain forest loss, this study focuses on the trends in patch sizes of forest loss during the 21st century. The annual area of tropical mountain forest loss surged from 0.7 million hectares in 2001–2003 to >2.5 million hectares in 2019–2021. There was an increase across all categories in terms of the size of forest loss patches, but strikingly, more than half of this increase was attributed to the proliferation of intermediate-sized forest loss patches spanning 1–10 ha. Concurrently, there was a diminishing proportion of small-scale montane forest loss patches (<1 ha) across all tropical continents over time. Despite their reduced overall proportion, the annual area of small forest loss patches increased, primarily influenced by trends in the Asia-Pacific region. Our study provides up-to-date and spatially explicit information on the scale of tropical mountain forest loss, and temporal trends associated with these patterns, which is crucial for assessing the sustainability of mountain forest ecosystems, highlighting the need for targeted, region-specific strategies to slow or reverse forest loss.
Assessing the robustness and implications of econometric estimates of climate sensitivity
Authors: Storelvmo Trude , Yuan Menghan , Leirvik Thomas , Alterskjær Kari , Phillips Peter C B , Smith Chris
Published: January 2025

Earth’s transient climate response (TCR) quantifies the global mean surface air temperature change due to a doubling of atmospheric

CO
2

concentration after 70 years of a compounding 1% per year increase. TCR is highly correlated with near-term climate projections, and thus of relevance for climate policy, but remains poorly constrained in part due to uncertainties in the representation of key physical processes in Earth System Models (ESMs). Within state-of-the-art ESMs participating in the Coupled Model Intercomparison Project (CMIP6), the TCR range (1.1 ∘C–2.9 ∘C) is too wide to offer useful guidance to policymakers. Similarly, the sixth report of the Intergovernmental Panel on Climate Change, while not solely reliant on ESMs for its TCR assessment, produced a very likely range of 1.2 ∘C–2.4 ∘C. To complement earlier, ESM-based, estimates, we here present a new TCR estimate of 2.17 (1.72–2.77) ∘C (95% confidence interval), derived based on a statistical relationship between surface air temperature and observational proxies for its main drivers, i.e. changes in atmospheric greenhouse gases and aerosols. We show that, within uncertainty, this method correctly diagnoses TCR from 20 CMIP6 ESMs if the same input variables are taken from the ESMs that are available from observations. This increases confidence in the new observation-based central estimate and range, which is respectively higher and narrower than the mean and spread of the estimates from the entire ensemble of CMIP6. Many ESM-based estimates tend to produce TCRs lower than the observational range reported here. Our findings suggest that a misrepresentation of the aerosol cooling effect could be the cause of this discrepancy. Further, the revised TCR estimate suggests a downward revision of the remaining carbon budgets aligned with the overarching goal of the Paris agreement.
Hybrid data augmentation strategies for robust deep learning classification of corneal topographic maptopographic map
Authors: Chaari Abir , Kallel Imen Fourati , Kammoun Sonda , Frikha Mondher
Published: January 2025

Deep learning has emerged as a powerful tool in medical imaging, particularly for corneal topographic map classification. However, the scarcity of labeled data poses a significant challenge to achieving robust performance. This study investigates the impact of various data augmentation strategies on enhancing the performance of a customized convolutional neural network model for corneal topographic map classification. We propose a hybrid data augmentation approach that combines traditional transformations, generative adversarial networks, and specific generative models. Experimental results demonstrate that the hybrid data augmentation method, achieves the highest accuracy of 99.54%, significantly outperforming individual data augmentation techniques. This hybrid approach not only improves model accuracy but also mitigates overfitting issues, making it a promising solution for medical image classification tasks with limited data availability.
Research on the Driving Paths of Bilateral Renewable Energy Trade between Neighboring Countries and China from the Perspective of Behavioral Attribution
Authors: Yang Zijie
Published: January 2025

The bilateral trade in renewable energy between China and its neighbors represents a global cooperative endeavor influenced by various factors. However, few studies have conducted a comprehensive examination of the behavioral attribution-based reasons behind the bilateral cooperation in renewable energy between China and its neighbors. This study breaks down the aspects of cooperation willingness, cooperation capability and cooperation environment, along with their respective components, based on international behavioral attribution theory. To determine the configurational pathways of each constituent element's role in the bilateral renewable energy trade cooperation between each case country and China, this paper employs a mixed-method approach of Necessary Condition Analysis (NCA) and fuzzy-set Qualitative Comparative Analysis (fs-QCA), selecting 20 'country-stage' cases based on data availability. The study finds that for neighboring nations to engage in substantial renewable energy trade with China, extensive use of market-incentive policy instruments is essential. Additionally, favorable bilateral political ties, a lower level of nationalism and increased energy security within surrounding nations are critical factors in fostering extensive renewable energy trade with China. Meanwhile, the economic vulnerability and reliance of different nations on China have varying impacts on their final trade in renewable energy with China. The study identifies five configurational pathways that drive large-scale renewable energy trade cooperation between neighboring countries and China, as well as four configurational pathways that constrain such cooperation.