bluuebunny/crossref_metadata_2025_split huggingface dataset:
Centring Race: Unpacking Informality Through the Lens of Black Tax
Authors: Annalena Oppel 
Published: November 2024

AbstractTaking a historical and contextual approach to racialization, this study seeks to unpack informality in the development of welfare regimes. By centring race as a conceptual lens, it elicits knowledge hierarchies that exist within the formulation of social policies; particularly concerning the classification of informal/formal practices. It thereby draws on Black Tax as a lived example of family and kinship support in Southern Africa, in the development discourse predominantly understood as informal social protection or informal safety nets. Black Tax, however, is a colloquial term that claims its non-Western origin and struggle to co-exist in a Westernized unequal society. It does so by stressing its racialized nature as a necessary practice in response to racial inequality but also as a form of alienation from its origin, being the African philosophy of Ubuntu. In showing consequences and internal conflicts that arise when living across dominant (Western) and subaltern (African) divides, it challenges colonial dichotomies that continue to dominate the development discourse. In highlighting what the informal/formal dichotomy overlooks, the study seeks to encourage a process of repositioning and expanding informality to better account for its political role in ‘thinking’ and ‘doing’ development.
Dynamics of ionic liquid–polymer gel membranes—Insight from NMR relaxometry for [BMIM][BF4]–PVDF-HFP systems
Authors: Singh Shitanshu Pratap , Masiewicz Elżbieta , Singh Rajendra Kumar , Chaurasia Sujeet Kumar , Kruk Danuta 
Published: November 2024

1H spin–lattice relaxation experiments have been performed for ionic liquid–polymer gel membranes, including 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]) and poly(vinylidene fluoride-co-hexafluoropropylene) (PVdF-HFP) with different proportions. The experiments have been performed in a broad range of resonance frequencies (from about 5 Hz to 40 MHz) vs temperature and complemented with analogous studies for [BMIM][BF4] in bulk as a reference. A model of the relaxation processes in the membranes has been proposed. The model includes two relaxation contributions. One of them corresponds to the concept of restricted, two-dimensional translation diffusion with a residence lifetime, while the second one has the form characteristic of polymers (mathematically similar to the limiting behavior of two-dimensional translation diffusion with a very long residence lifetime). The extensive dataset has been consistently interpreted in terms of the model, revealing two dynamical processes on the time scales of 10−7 s (for the second relaxation contribution) and 10−9 s (for the first one). The relationship of these relaxation contributions to the motion of the polymer or ionic liquid–polymer complexes and to the translation diffusion of BMIM cations in the matrix has been discussed.
Electrode materials optimize operating voltage and switching speed in micro/nano plasma ultrafast devices
Authors: Xu Weiqiang , Wu Jian , Zheng Zhongyang 
Published: November 2024

Abstract
The trade-off between ultrahigh speed and low operating voltage is a major challenge in the continuous improvement of modern electronics. Although micro/nano plasma devices have demonstrated the potential of picosecond switching speed and high output power, surpassing traditional electronic devices, versatile methods for optimizing the operating voltage and switching speed are highly desired. Here, an optimization scheme based on the work function of the electrode materials is reported, which reduces the operating voltage and improves the switching speed. Compared with traditional methods, such as narrowing gaps or distorting electric fields, this approach offers advantages such as reducing production costs, enhancing consistency, and improving tunability. The experimental results show that using silver as a low-work-function electrode material can reduce the operating voltage by 55% to 180 V and increase the switching speed by 58% to 7.1 V ps−1 compared to platinum, which is equivalent to a 71% reduction in gap size. In addition, the underlying working mechanisms and inherent advantages of the approach are demonstrated, providing new insights for the ultrahigh switching speed and low-power application of micro/nano plasma devices, such as high-speed communication and ultrafast electronics.
Ultrafast terahertz conductivity in epitaxial graphene nanoribbons: an interplay between photoexcited and secondary hot carriers
Authors: Singh Arvind , Němec Hynek , Kunc Jan , Kužel Petr 
Published: November 2024

Abstract
Optical pump-terahertz probe spectroscopy has been used to investigate ultrafast photo-induced charge carrier transport in 3.4 µm wide graphene ribbons upon scaling the optical pump intensity. For low pump fluences, the deposited pump energy is rapidly redistributed through carrier–carrier scattering, producing secondary hot carriers: the picosecond THz photoconductivity then acquires a negative sign and scales linearly with an increasing pump fluence. At higher fluences, there are not enough equilibrium carriers able to accept the deposited energy, directly generated (excess) carriers start to contribute significantly to the photoconductivity with a positive sign leading to its saturation behavior. This leads to a non-monotonic variation of the carrier mobility and plasmonic resonance frequency as a function of the pump fluence and, at high fluences, to a balance between a decreasing carrier scattering time and an increasing Drude weight. In addition, a weak carrier localization observed for the polarization parallel to the ribbons at low pump fluences is progressively lifted upon increasing the pump fluence as a result of the rise of initial carrier temperature.
Stability and reversibility of organic molecule modifications of CVD-synthesized monolayer MoS2
Authors: Lovro Brkić Antun , Supina Antonio , Čapeta Davor , Dončević Lucija , Ptiček Lucija , Mandić Šimun , Racané Livio , Delač Ida 
Published: November 2024

Abstract
We investigated the stability of monolayer MoS2 samples synthesized using chemical vapor deposition and subsequently modified with organic molecules under ambient conditions. By analyzing the optical signatures of the samples using photoluminescence spectroscopy, Raman spectroscopy, and surface quality using atomic force microscopy, we observed that this modification of monolayer MoS2 with organic molecules is stable and retains its optical signature over time under ambient conditions. Furthermore, we show the reversibility of the effects induced by the organic molecules, as heating the modified samples restores their original optical signatures, indicating the re-establishment of the optical properties of the pristine monolayer MoS2.
Study on the analytical verification method of geometric error models
Authors: Liu Jixiao , Chen Qingrong , Wang Jian , Sun Si , Zhang Xi , Du Jialin , Jiang Jixin , Tian Zongwei , Yu Siyang , Yan Wei 
Published: November 2024

Abstract
Geometric error compensation is a widely used and effective approach for enhancing the accuracy of Coordinate Measuring Machines (CMMs) and Computer Numerical Control (CNC) machines. The research in this field primarily focuses on the challenging task of developing geometric error modelling techniques. Currently, there are several well-established methods for modelling geometric errors. However, there is scarce availability of methods that can validate the established geometric error models. Therefore, this article proposes an analytical validation method for geometric error models based on the error transformation equation. The principle of the method is elaborately explained, and its correctness is verified through specific model verification example. The method proposed in this article enables rapid and accurate model correction and iteration, effectively reducing the economic and time costs of model validation in the current geometric error compensation process. Therefore, the method provides guidance for standardising the modelling process and could be widely applied to various structural forms of measurement and machining systems.
Design and optimization of two-terminal InGaP/Si tandem solar cell through numerical simulation
Authors: Kharchich Fatima Zahra , Khamlichi Abdellatif 
Published: November 2024

Abstract
The III-V/Si double junction solar cells demonstrate cost-effective performance comparable to III-V/III-V tandems, with an efficiency of 35.9%, below the 43% theoretical limit. Considering monolithic InGaP//Si based tandem solar cell, this work dealt with the optimization of its efficiency as a function of layer thicknesses and dopings. Considering ideal optoelectronic parameters of materials, numerical simulations were performed by using Silvaco/ATLAS TCAD software. They were conducted within the context of a multi-step optimization procedure that was proposed in this work. The obtained optimum tandem InGaP//Si structure reached an unprecedented power conversion efficiency of 40.74% under 1.5G spectrum.
Introducing boron gallium nitride as carriers’ source layer for efficient near-ultraviolet microLED
Authors: Bashir Jamshad , Usman Muhammad , Sengouga Nouredine , Hassani Mohamed 
Published: November 2024

Abstract
This study explored the impact of boron gallium nitride (BGaN) in buffer layer and hole source layer. We employed B0.05Ga0.95N which reduced the lattice mismatch as well as the electric field. BGaN not only minimized the number of electrons leaking out of quantum wells (QWs) but also improved the hole injection. It is evident from our simulations that internal quantum efficiency (IQE) is enhanced significantly as more carriers are available for radiative recombination in multiple quantum wells (MQWs). Along with the increase in IQE, droop is also reduced in BGaN ultraviolet light-emitting diodes. Significantly high luminous power and emission intensity were observed along with slight blueshift because of minimized quantum confinement stark effect (QCSE).
Design and characterization of a circular ring monopole antenna and its MIMO configuration for sub-6 GHz, sub-7 GHz and mm-wave 5G applications
Authors: Iriqat Sanaa , Yenikaya Sibel , Secmen Mustafa 
Published: November 2024

Abstract
In this paper, a circular ring monopole antenna, along with its MIMO configuration for sub-6 GHz, sub-7 GHz and mm-wave 5G applications is presented. The single element spans a wide range of frequencies in the sub-6 GHz and mm-wave regions, including a triple-band covering 1.9–6 GHz, 23.3–33.5 GHz, and a super-wide band starting from 37.5 GHz. A two-element MIMO antenna, derived from the single element, has been developed to operate in both frequency regions. It meets the −10 dB criterion with a bandwidth of 4.8 GHz (3.2 to 7.3 GHz) in the sub-6 GHz/sub-7 GHz spectrum. Additionally, the antenna exhibits a super-wide band in the mm-wave region starting at 30.4 GHz. The design covers key bands such as n78, LTE band 46, n96, 39 GHz band, 41 GHz band and more, assigned for 5G sub-6 GHz, sub-7 GHz and mm-wave applications. Improved isolation from 12 dB to 18.5 dB is achieved through a simple decoupling line structure between elements. The proposed MIMO antenna (75 × 56.4 × 1.52 mm3) exhibits a peak gain of 9.8 dBi, high isolation (18.5 dB), low envelope correlation coefficient (ECC <0.016 ), high diversity gain (DG > 9.995), and efficiency (< 97%).
A new ultra-compact communications system across air-sea water based on ELF magnetic mechanical antenna
Authors: Zhang Wenhou , Cao Zhenxin , Wang Xiaoyu , Liu Tong , Wang Zongxin 
Published: November 2024

Abstract
In this paper, a long-range trans-air-seawater medium communication system is proposed based on a small extremely low-frequency (ELF) mechanical antenna. We analyze the propagation characteristics of ELF electromagnetic waves in seawater and determine the paths of ELF electromagnetic waves propagating across domains. Equivalent models of various mechanical antennas are analyzed based on their operating principles. Based on the equivalent model, the transmission principle of mechanical antenna in transmitting across air-sea medium is analyzed, and finally the mechanical antenna with permanent magnet working horizontally is identified as the optimal choice. The above results are also verified by simulation. Experimental and simulation results verify the good performance of a horizontally operating permanent magnet mechanical antenna in transmitting across air-sea medium. The ELF-band transmission communication across air-sea medium based on binary code modulation is realized, and the farthest transmission distance can reach 200m in the experiment. Based on this system, transmission in air was also tested up to a distance of 1.5 km. The ELF transmission across air-sea medium based on a permanent magnet mechanical antenna can greatly facilitate cross-domain teleportation and ocean exploration.
Comparative analysis of two novel chaotic systems, and validation of hybrid function projective and complete synchronization using active-adaptive control
Authors: Khattar D , Sirohi M , Bansal R 
Published: November 2024

Abstract
This study investigates the nonlinear characteristics of two novel 3D-chaotic models using phase portraits, bifurcation diagrams, Lyapunov exponents, time series analysis, and Poincaré maps. Here, we have examined hybrid-function projective and complete synchronization schemes via adaptive and active control methods. Moreover, the performance of hybrid-function projective synchronization, utilizing sine, cosine, and exponential terms, is compared to complete synchronization through two control strategies. Our designed controllers ensure asymptotic global chaotic synchronization based on Lyapunov stability principles. We have also compared our results with other competitive schemes and validated the theoretical findings through simulations on the MATLAB platform.
Welding residual stress analysis based on ABAQUS direct coupling
Authors: Pan Yunping , Zhang Cheng , Feng Zhongyin 
Published: November 2024

Abstract
Taking the welded joints of the drive axle shell and half shaft casing as the research object, based on the ABAQUS engineering software and its DFLUX subroutine, numerical simulation of the residual stresses of the welded joints before and after the heat treatment is carried out by adopting the direct coupling of temperature-displacement and the method of birth-death unit, to analyze the improvement effect of post-weld heat treatment on the residual stress of welded joints. The results show that the heat treatment process significantly reduces the equivalent peak stress of welded joints, from the original 195.25 MPa to 145.21 MPa, with a decrease of 25.6%. The axial peak stress of the welded joints decreased from 170.94 MPa to 130.84 MPa, with a decrease of 23.5%.
Study on the influence of thermal properties of paraffin on flexible PTC materials
Authors: Hao Jianmin , Yang Yinfa , Chen Hua , Cheng Wenlong 
Published: November 2024

Abstract
This paper experimentally studied paraffin’s influence on flexible PTC materials’ temperature resistance and flexibility. Their resistance-temperature characteristics are notably influenced by PA’s phase transition range thermal properties. Specifically, the Curie temperature is intricately linked and determined by the PA’s phase transition temperature. PA’s phase state and proportion in the composite directly impact PTC material flexibility significantly. Specifically, a lower PA phase transition temperature results in better flexibility of PTC materials at room temperature. Additionally, a lower PA content minimizes interference with the overall flexible mesh structure, further enhancing material flexibility. The PTC of this series of formulations showed good adaptive temperature control ability. The thermal control performance can be customized by adjusting the PA.
Optimization study of air-cooled heat dissipation structure based on waterborne electric airplane
Authors: Fan Xinyue , Liao Jicheng , Wang Shuli 
Published: November 2024

Abstract
Taking the water electric aircraft as the research object, to solve the problem of high temperature of the motor, controller and radiator in the powerhouse when the aircraft is travelling under the high temperature condition in summer. Firstly, the three-dimensional model of the power module of the electric aircraft is established and simulation experiments are carried out, and then according to the simulation results, the power module is optimized and improved, and after simulation experiments, it is known that the highest temperature of the surface of the electric motor is 432.83K, the highest temperature of the surface of the controller is 370.82K, and the highest temperature of the surface of the radiator is 368.67K, and the final experimental results show that the optimization meets the cooling requirements of the aircraft flight. The final experimental results show that the optimisation meets the heat dissipation requirements of the aircraft flight.
Simplified modeling study of the forward fuselage structure based on the overall structural rapid design software for civil aircraft
Authors: Li Feng , Pan Lijun 
Published: November 2024

Abstract
In order to solve the problems of poor weight estimation accuracy and difficult layout design trade-offs in the concept demonstration and overall program definition stage of civil aircraft, Aircraft Layout, a civil aircraft overall program structure rapid design software, is used to establish a numerical calculation-based layout program rapid design simulation platform. Based on the forward fuselage structure, this paper gives the results of rapid modeling and finite element simulation and analysis of the forward fuselage isotropic section of a certain type of aircraft, which provides a reference for the optimization design of the structural components of the forward fuselage section of a certain type of aircraft in the conceptual scheme design stage.
Study on the suppression of secondary electron emission characteristics based on TiN
Authors: Miao Guanghui , Duan Penghui , Li Xiongfei , Cui Wanzhao 
Published: November 2024

Abstract
With the continuous development of satellite communications, the problem of high-frequency high-power multipactor caused by the miniaturization of microwave passive components in the aerospace field has become more and more serious. In this paper, for the problem of multipactor suppression of load passive devices, we carried out research on the preparation of TiN thin films based on PEALD and put forward a new method for suppressing SEE with good suppression effect, high consistency, low surface resistance, and other aspects of the unity of the multipactor effect. The use of 20nm TiN coating can make the silver-plated surface secondary electron emission coefficient down to 1.59. The RF surface resistance change rate is less than 3%. In the field of communication, satellite and navigation and other fields have a wide range of application prospects.
Performance evaluation of vibration-damping bucking bar in human-robot collaboration
Authors: Zhan Yingzhao 
Published: November 2024

Abstract
The riveting process in aircraft manufacturing generates large vibrations, and if it is exposed to vibration for a long period of time, riveting workers may suffer from Hand-Arm Vibration Syndrome causing irreversible damage to the robot. In this study, firstly, the vibration mechanical model of human-robot collaboration was established, and then the vibration characteristics of human-robot collaboration under squeezing force were deduced. Finally, an experiment was performed to evaluate the vibration damping performance of vibration-damping bucking bars by evaluating the mean peak squeezing force with different rivet guns and input pneumatic pressure. Compared with the conventional stainless steel bucking bar, the PU-cylinder bucking bar has a lower mean peak squeezing force. The results show that the utilization of the PU-cylinder bucking bar in human-robot collaborative riveting operations can considerably reduce the vibration transmitted from the rivet gun to the robot and the operator.
Three-dimensional visible light positioning through fisheye camera
Authors: Liu Xiangyu , Zhang Junqi , Zhao Liqin , Guo Lei 
Published: November 2024

Abstract
Visible light can be utilized to achieve indoor high-precision positioning. However, most visible light positioning (VLP) systems only achieve two-dimensional (2D) positioning and require a dense LED layout as the transmitter. Therefore, we propose a novel three-dimensional (3D) visible light indoor positioning system, which uses the fisheye camera as the receiver, designs an LED width comparison method to reduce the requirement of LED density, and realizes 3D positioning. When images captured by the fisheye camera distort, we use the checkerboard calibration method to correct the distortion parameters of the fisheye camera. The parameters can be used to improve the impact of image distortion on the positioning effect. For the LED width comparison method, we set up a discrete height-width database, fit a curve between height and LED width, and calculate the receiver height according to the linear relationship. Extensive results show that the positioning system can achieve a 3D positioning with 9.66cm average error.
Experimental study of cross-correlation algorithm based on background schlieren quantization in natural thermal convection field
Authors: Shen Pei-En , Zhong Yuan , Ling Zhen-Qiang , Li Ming-Yu , Zhu Hai-Dong 
Published: November 2024

Abstract
The background shading technology has shown a wide application potential in many fields. This study aims to study the thermal convection field above the flame. In this study, we established a large field shading system, which is used to observe the flow field distribution and the high temperature probe at the corresponding position above the flame flow field, and then the temperature change map of the corresponding position of the flow field is obtained. The experimental results show the advantages of the large field of view shading system based on background shading technology in the temperature distribution image of the flow field, and make up for the vacancy and deficiency of the application in the optical field. This study is also helpful to better reveal the nature of the combustion process. The development of research will provide a new perspective for the further application of background shading technology.