bluuebunny/crossref_metadata_2025_split huggingface dataset:
Advanced temporal analysis of anode activity during mode transitions in high current vacuum arcs
Authors: Dorraki Naghme , Methling Ralf , Gortschakow Sergey 
Published: November 2024

Abstract
Anode activity in high current vacuum arcs leads to the formation of various high current modes and transitions between them. Intense material evaporation during the anode spot mode and formation of a neutral vapour cloud during the anode plume mode modify the arc plasma properties and, hence, can have a crucial impact in applications, like e.g. reduction of interruption performance of switching devices. The influence of anode mode appearance on arc plasma parameters and on anode surface temperature was studied in detail by a novel optical diagnostic technique—intensified video optical emission spectroscopy. Employing advanced diagnostic methods, the ground state density, excitation temperature and pressure profiles close to the anode surface have been determined. For the anode plume mode, higher copper vapour pressure was found in the plume shell compared to its core. The copper ion density distribution shows a maximum outside of the plume shell. Consequently, a higher electrical conductivity in the surrounding area of the plume might be expected, i.e. the arc current flows around the plume rather than through it. Analysis of the temporal evolution of electrical and optical signals reveals that voltage jumps and drops during the mode transitions are accompanied by noticeable changes in the anode surface temperature. Thus, the formation of the anode plume leads to temperature lowering while the transition to the anode spot mode is accompanied by a temperature increase. In general, a clear correlation between electrode surface temperature and arc voltage in the case of constricted anode attachment is found. The results of this study give new insights into anode plume properties and consequences of anode mode transitions. Reversible mode transitions and correlations between arc voltage and anode surface temperature, as well as changes in the current path during anode plume mode, have to be considered as factors for optimization of electrode design and choice of materials for switching applications.
Design and test of the electrostatic actuation system of the inertial sensor for space gravitational wave detection
Authors: Zhang Qianyun , Yin Hui , Xiang Yu , Wu Shufan 
Published: November 2024

Abstract
The electrostatic actuation system is one of core control mechanisms of the inertial sensor for space gravitational wave detection, and its performance directly affects the residual acceleration of the test mass of the inertial sensor on the sensitive axis. Based on analyzing the working principle of the electrostatic actuation system and its performance requirements allocated from mission and spacecraft requirements, this paper presents the detailed analysis, design, and achieved performance of a prototype electrostatic actuation system, which consists of a set of 12-channel electrostatic actuation circuits., It has two working modes: a high-precision mode with a range of ±10 V and a wide-range mode with a range of ±150 V actuation voltage. The important problem of noise coupling between high-voltage devices and low-voltage devices is solved by a power management and output channel switching mechanism on hardware, which is an innovative solution. The test results demonstrate that the output functions of the wide-range and high-precision modes are normal, and the mode-switching process is stable. In the high-precision mode, at 10 V full-scale output, the maximum output DC voltage noise of the 12 channels is 11.8 μV/Hz1/2, translating to an amplitude stability of 1.18 ppm/Hz1/2.
Magnetic domain wall and skyrmion manipulation by static and dynamic strain profiles
Authors: Moore Thomas A 
Published: November 2024

Abstract
Magnetic domain walls and skyrmions in thin film micro- and nanostructures have been of interest to a growing number of researchers since the turn of the millennium, motivated by the rich interplay of materials, interface and spin physics as well as by the potential for applications in data storage, sensing and computing. This review focuses on the manipulation of magnetic domain walls and skyrmions by piezoelectric strain, which has received increasing attention recently. Static strain profiles generated, for example, by voltage applied to a piezoelectric-ferromagnetic heterostructure, and dynamic strain profiles produced by surface acoustic waves, are reviewed here. As demonstrated by the success of magnetic random access memory, thin magnetic films have been successfully incorporated into complementary metal-oxide-semiconductor back-end of line device fabrication. The purpose of this review is therefore not only to highlight promising piezoelectric and magnetic materials and their properties when combined, but also to galvanise interest in the spin textures in these heterostructures for a variety of spin- and straintronic devices.
A concurrent multiscale model of stress-induced delamination behaviours of epoxy-impregnated rare-earth barium copper oxide superconducting pancake winding
Authors: Guo Hanxiao , Gao Peifeng , Chen Sikan , Zhu Jiamin 
Published: November 2024

Abstract
Rare-earth barium copper oxide (REBCO) coated conductor (CC) tapes are promising for high-energy and high-electromagnetic field applications. In epoxy-impregnated REBCO superconducting coils, due to the weak c-axial strength of REBCO CC tapes, delamination induced by thermal-mismatch stress and Lorentz force significantly threatens stable operation. The commonly used numerical modelling methods mainly include homogenized model and refined model. The former can realize the efficient calculation of the overall physical field but lose the local details including interfacial delamination behaviour, while the latter can realize the refined calculation but cost massive calculation. In this study, combining with bilinear cohesive zone model (CZM), a two-dimensional axisymmetric concurrent multiscale model was developed to balance the efficiency-accuracy trade-off for numerically investigating the mechanical properties and interface failure behaviours of REBCO superconducting coils under cryogenics and high-electromagnetic field. In the presented model, the homogenized superconducting coil was firstly constructed based on composites homogenized approach to estimate the electromagnetic-thermal-mechanical properties at macro scale. Then, the ‘dangerous regions’ in the macro scale was recognized based on quadratic failure criterion and replaced with a refined model considering delamination failure defined by CZM. Finally, the two scales are linked through the coupling interface. The accuracy and efficiency of the concurrent multiscale model were validated by refined model for the cases of delamination behaviour during cooling and excitation.
Eloquent numerical approach for solving generalized time fractional convection-diffusion-reaction problems
Authors: S Poojitha , Awasthi Ashish 
Published: November 2024

Abstract
This paper attempts to develop a spectral method based on derivatives of orthogonal polynomials to solve the time fractional convection–diffusion-reaction equations. The method utilizes derivatives of fractional order orthogonal functions to approximate derivatives involved in the fractional differential equations. Specifically, the derivatives of fractional order Legendre functions and fractional order Chebyshev functions are used to represent both integer and non-integer derivatives of the solutions. These derivative representations are achieved through the use of operational matrices, which are matrices that encode the operations performed on the polynomials. An attempt is made to derive the operational matrix of Vieta-Fibonacci-like polynomials and used to solve the fractional differential equations. The derived operational matrix provides a systematic way to manipulate and work with these polynomials, facilitating their application in various mathematical and engineering problems. By employing these operational matrices, the original fractional convection–diffusion-reaction equation is transformed into a system of linear or nonlinear algebraic equations. However, if the system is nonlinear, a Newton-like solver is applied, which is capable of handling nonlinear systems. The estimation of error bounds of numerical solutions is also given. The numerical experiments have been performed over a few test examples to validate the proposed numerical method. The use of fractional order functions highlights their ability to solve fractional differential equations with non-smooth solutions accurately.
Mathematical modeling development and synthesis of tapered transmission line resonators and filters
Authors: Rehman Sajjad Ur , Alkanhal Majeed A S , Ahmad Mohaira , Malik Waqar A , Abdulkawi Wazie M , Salim Ahmed , Sheta Abdel-Fattah A 
Published: November 2024

Abstract
Tapered transmission line resonators can be used to achieve specific frequency responses and enhance the performance of microwave devices and impedance transformers. To develop a mathematical model (transfer function) of such a wideband resonator will facilitate the construction of an equivalent circuit and the synthesis of resonators of this type. This study discusses the system modeling of tapered transmission line (TTL) resonators using the singularity expansion method (SEM). The transfer function is analytically established for two types of wideband TTL resonators: exponential tapered transmission lines (ETTL) and linear tapered transmission lines (LTTL). The analytical transfer function is derived for the general tapered ratio (k/β). The physical poles of the structures are identified using the pole-energy matrix pencil (MP) approach. The transfer function expression is then utilized to develop an accurate equivalent lumped-element circuit for the TTL resonator. This study’s simplified approach for estimating the transfer function and associated poles and zeros from the S-parameters is the main contribution, whereas it is known that the transfer function becomes complicated for wideband frequency response. A direct synthesis approach is presented to develop two-stage and four-stage ultra-wideband (UWB) bandpass filters. The agreement between the frequency response data and the derived transfer function of the system model of the synthesized TTL filters demonstrates the reliability of the presented method. The proposed system modeling and synthesis methodology can be applied to more sophisticated filter TTL architectures.
Unravelling the effect of strain on the electronic structure, elastic and thermoelectric properties of half-Heusler alloy CoHfSi
Authors: Matth Sadhana , Pandey S , Pandey Himanshu 
Published: November 2024

Abstract
Before realizing any device’s actual application, it is necessary to understand the material’s performance through first-principles investigations. Most of the devices consist of nanomaterials, especially thin film-based ones, which are under strain due to a lattice mismatch. This occurs between the thin film of active material and the substrate on which the thin film is grown. This strain affects the material’s properties and overall device performance. In this work, we comprehensively explored strain engineering’s impact on the electronic and thermal transport characteristics of the CoHfSi half-Heusler alloy. Employing the self-consistent ultra-soft pseudo-potential method and generalized gradient approximation within a density functional framework, we investigated the effect of both isotropic- and tetragonal-type strains. Strains were applied in both compressive and tensile categories. A semiconducting ground state with an indirect band gap of 1.248 eV is found under 5% compressive isotropic strain, which reduces to 0.847 eV for 5% tensile strain under the same type. On the other hand, the semiconducting energy bandgap increases from 0.986 eV (for 5% compressive) to 1.217 eV (for 5% tensile) for tetragonal strain. The power factor increases with the increase in temperature. It obtains a maximum value of ≈2.4 × 1012 Wm−1K−1s−1 for −5% isotropic and +5% tetragonal strain, and around this doping level, a better TE efficiency can be achieved. A maximum and saturated value of zT at 300 K and beyond is estimated to be more than 3.5 and 3 for −2% and −1% isotropic strain, respectively. For +5% isotropic strain, the electronic fitness function attains a maximum ∼9 × 10−20 W5/3ms−1/3K−2 at 800 K, irrespective of strain type. All these results provide novel insights into the strain-induced effects on the electronic and thermoelectric properties of mechanically and thermodynamically stable CoHfSi at elevated temperatures. Apart from strain-induced modifications, optimum p-type doping can also increase the power factor, figure-of-merit, and electronic fitness function of these strained CoHfSi half-Heusler alloys, demonstrating them as a suitable and promising candidate for thermoelectric applications.
Single-longitudinal mode quadruple wavelength C+L-band erbium-doped fiber laser based on the pairs of reflective fiber bragg gratings
Authors: Mirza Jawad , Atieh Ahmad , Kanwal Benish , Ghafoor Salman , Kausar Tasleem , Imran Muhammad , Almogren Ahmad , Kanwal Firdos , Aziz Imran 
Published: November 2024

Abstract
Flatness of lasing wavelengths of a multi-wavelength fiber laser (MWFL) is an important design constraint that is considered attractive in various applications of photonics and optical communication systems. In this work, we propose a single-longitudinal mode (SLM) quadruple wavelength C+L-band Erbium-doped fiber laser (EDFL) with high output power flatness. It is implemented with a short piece of Erbium-doped fiber (EDF) pumped by conventional 980 nm laser diode and four pairs of reflective fiber Bragg gratings (FBGs) through numerical simulations. The reflectivities of FBGs are adjusted such that SLM quadruple wavelengths are obtained at the output of EDFL with flatness of 0.9 dB, optical signal-to-noise ratio (OSNR) in the range of 44.5–53.2 dB, and linewidths (LWs) in the range of 5.4–7.3 MHz. Slope efficiency (SE) of around 24% is achieved considering the total power of all lasing wavelengths generated. Moreover, the power variation around 0.1 dB for lasing wavelengths of 1540.2 nm and 1605.7 nm is noticed for twelve iterations each repeating after five-minute interval. The proposed SLM quadruple wavelength EDFL has promising application prospects for distributed sensing and optical communication systems due to excellent performance metrics.
NIM diffuse reflectance scale to super black level (0.0001)
Authors: Feng Guojin , Zheng Chundi , Gan Haiyong , Lin Yandong , Wu Houping , Sun Ruoduan , Zhang Qiaoxiang , He Yingwei , Ma Yuxuan 
Published: November 2024

Abstract
The realization of the super black level diffuse reflectance scale of the National Institute of Metrology (NIM, China) is presented. Two facilities were used to achieve the reflectance scale under 0 d condition covering 0.0001–1.0 (absolute value), the first one based on the supercontinuum light source was used to realize the diffuse scale in the wavelength range 500 nm–2000 nm, while the other one based on QCL was applied for the mid infrared range from 7.5 μm to 10.6 μm. The relative expanded uncertainty (k = 2) of the reflectance scale was evaluated to be from 2.3% to 8.4% varying with range and wavelength in visible band to near infrared band while the reflectance is down to 0.0001. In the mid infrared band, the uncertainty of the reflectance scale was up to 8.9% while reflectance is 0.001, and up to 42.6% while reflectance is down to 0.0001. This low reflectance level scale can meet the calibration requirement of super black material or system such as carbon nanotube or blackbody.
Fast ion studies in the extended high-performance high βP plasma on EAST
Authors: Sun Y.X. , Huang J. , Gong X.Z. , Garofalo A.M. , Salewski M. , Varela J. , Qian J.P. , Zhang X.J. , Fan T.S. , Wang J.F. , Zhang W. , Hao B.L. , Gao W. , Chang J.F. , Zhong G.Q. , Zang Q. , Liu H.Q. , Lyu B. , Xie Y.H. , Wang X.H. 
Published: November 2024

Abstract
Comprehending and optimizing fast ion behaviors is critical for the enhancement of performance in Experimental Advanced Superconducting Tokamak (EAST). This study explores the potential benefits of several factors that can improve the fast ion confinement. First, experiments show the change in the direction of the NBI2 from counter-I
p to co-I
p leads to a significant reduction in fast ion losses. TRANSP/NUBEAM simulation and tomography results based on fast-ion D-alpha measurements reveal that after the neutral beam injection (NBI) upgrade, the beam ion prompt loss is reduced by approximately 50%. Second, the upgraded ion cyclotron resonant frequency (ICRF) antenna at the N-port features twice the coupling resistance of the original antennas at EAST. This improved ICRF power coupling has enhanced the synergistic heating effect of NBI + ICRF, where the ICRF wave field accelerates beam ions at the harmonics. Experiments demonstrate that NBI + ICRF synergistic not only enhances plasma neutron yield and β
P, but also accelerates beam ions to hundreds of keV. Further, the electron density and the neutral beam voltage have been optimized to reduce the fast ion slowing-down time and beam ion losses. Experimental and simulation results indicate that increasing the electron density reduces beam ion losses and enhances the bootstrap current fraction. While higher beam voltage results in a slight decrease in beam power absorption, it can increase the fraction of bootstrap current. With the understanding of these optimization of fast ion confinement, experiments have demonstrated fully non-inductive operation at high density (n
e/n
G ∼ 0.67, β
P ∼ 3.1, β
N ∼ 2.1, H
98,y2 ∼ 1.2) even without the support of co-I
p beam NBI2. This investigation presents a potential regime to enhance fast ion confinement and extend performance in the high β
P plasma for future experiments.
Doxorubicin-loaded core@shell cobalt ferrite-barium titanate magnetoelectric nanofibers for improved anticancer activity
Authors: Shahzad Khuram , Abbasi Muhammad Ali , Rafe Muhammad Hassan , Pestereva Anna , Ullah Faheem , Zaman Muhammad , Irfan Muhammad , Afzal Muhammad , Orlova Anna 
Published: November 2024

Abstract
Conventional drug delivery systems often suffer from non-specific distribution and limited therapeutic efficacy, leading to significant side effects. To address these challenges, we developed magnetoelectric, cobalt ferrite@barium titanate (CFO@BTO) nanofibers (NFs), with a core–shell structure for targeted anticancer drug delivery. The electrospinning method was employed to synthesize polymeric NFs based on magnetoelectric core–shell nanostructures. The scanning electron microscopy, transmission electron microscopy, x-ray diffraction and Vibrating sample magnetometer analysis confirmed the successful loading of nanostructures on polymeric NF, the core–shell morphology and magnetoelectric phase of CFO@BTO, respectively. UV–Vis spectroscopy was applied to verify the drug attachment, the optimization of drug release in an applied external magnetic field (MF), and the time required for control drug release. The effectiveness of MF-assisted controlled drug release was demonstrated by achieving a 95 ± 1.03% drug release from magnetoelectric NFs (MENFs) within 30 min under a MF of 4 mT. In vitro cytotoxicity assay on human skin cancer (SK-MEL-28) cell lines exhibited a maximum 90 ± 2% cytotoxicity with 2 ± 0.03 cm of drug loaded MENFs. Furthermore, the Hemolysis assay was carried out to affirm the biocompatibility and non-toxicity of drug loaded MENFs, which is suitable for anticancer therapy.
An aligned pattern sponge based on gelatin for rapid hemostasis
Authors: Cao Dayong , Chen Yimin , Man Yulin , Chen Zhaohong 
Published: November 2024

Abstract
Post-traumatic hemorrhage is a leading cause of morbidity and mortality. However, most current hemostatic materials focus on incorporating nutritional components, with limited research addressing the impact of the material’s structure on hemostasis. In this study, we developed cytocompatible and hemocompatible three-dimensional gelatin sponges with a patterned and aligned structure, designed for rapid hemostasis. The sponges were characterized by light microscope photography and scanning electron microscopy (SEM). Pattern sponges with gelatin (P-Gelatin) exhibited aligned structures on their surfaces and the inner structure. In terms of biocompatibility, MTT assay, and hemolysis experiment showed that P-Gelatin had good cytocompatibility and hemocompatibility. In vivo blood coagulation and in vivo hemostasis, P-Gelatin sponges, with their aligned structure, exhibit rapid adsorption of red blood cells and platelets compared to non-patterned gelatin counterparts. This work introduces a safe and convenient patterned sponge for rapid hemostasis, especially highlighting a concept where a patterned structure can enhance the effectiveness of blood clotting, which is particularly relevant for tissue engineering.
The number of minima in random landscapes generated by constrained random walk and Lévy flights: universal properties
Authors: Kundu Anupam , Majumdar Satya N , Schehr Grégory 
Published: November 2024

Abstract
We provide a uniform framework to compute the exact distribution of the number of minima/maxima in three different random walk landscape models in one dimension. The landscape is generated by the trajectory of a discrete-time continuous space random walk with arbitrary symmetric and continuous jump distribution at each step. In model I, we consider a ‘free’ random walk of N steps. In model II, we consider a ‘meander landscape’ where the random walk, starting at the origin, stays non-negative up to N steps. In model III, we study a ‘first-passage landscape’ which is generated by the trajectory of a random walk that starts at the origin and stops when it crosses the origin for the first time. We demonstrate that while the exact distribution of the number of minima is different in the three models, for each model it is universal for all N, in the sense that it does not depend on the jump distribution as long as it is symmetric and continuous. In the last two cases we show that this universality follows from a non trivial mapping to the Sparre Andersen theorem known for the first-passage probability of discrete-time random walks with symmetric and continuous jump distribution. Our analytical results are in excellent agreement with our numerical simulations.