bluuebunny/crossref_metadata_2025 huggingface dataset:
Uncovering the essence of diverse media biases from the semantic embedding space
Authors: Huang Hong , Zhu Hua , Liu Wenshi , Gao Hua , Jin Hai , Liu Bang
Published: May 2024

Media bias widely exists in the articles published by news media, influencing their readers’ perceptions, and bringing prejudice or injustice to society. However, current analysis methods usually rely on human efforts or only focus on a specific type of bias, which cannot capture the varying magnitudes, connections, and dynamics of multiple biases, thus remaining insufficient to provide a deep insight into media bias. Inspired by the Cognitive Miser and Semantic Differential theories in psychology, and leveraging embedding techniques in the field of natural language processing, this study proposes a general media bias analysis framework that can uncover biased information in the semantic embedding space on a large scale and objectively quantify it on diverse topics. More than 8 million event records and 1.2 million news articles are collected to conduct this study. The findings indicate that media bias is highly regional and sensitive to popular events at the time, such as the Russia-Ukraine conflict. Furthermore, the results reveal some notable phenomena of media bias among multiple U.S. news outlets. While they exhibit diverse biases on different topics, some stereotypes are common, such as gender bias. This framework will be instrumental in helping people have a clearer insight into media bias and then fight against it to create a more fair and objective news environment.
Discourse construction of Chinese modernization from the perspective of Malaysian media
Authors: Wang Dongping , Liang Siping
Published: May 2024

This study uses corpus critical discourse analysis to examine the reporting strategies and affective attitudes of Malaysian media towards Chinese modernization. The analysis is based on 192 related news reports and aims to reveal how Malaysian media interpret and construct the discourse of Chinese modernization. The study finds that Malaysian media reports show a diversity of attitudes, with positive and neutral reports dominating and negative reports occupying a small proportion, which needs counter-stigmatization. The study emphasizes the importance of constructing the discourse of Chinese modernization and points out adopting flexible and diversified strategies to construct a foreign discourse system. This study provides new perspectives for understanding the concept of Chinese modernization in the context of globalization and highlights the importance of strengthening media exchanges and cooperation between China and Malaysia.
The effect of hydrostatic stress on magnetic properties of Mn-Zn power ferrites at varying excitation levels
Authors: Ellithy Ibrahim , Esguerra Mauricio , Radhakrishnan Rewanth
Published: May 2024

In this paper, the effects of hydrostatic stress on the magnetic properties of Mn-Zn power ferrites are discussed. Ring cores were embedded in cement and the curing process gradually exerted pressure on the core. A novel testing method was developed to continuously measure the power losses and the magnetic susceptibility in dependence on magnetic excitation at a fixed frequency and room temperature with a vector network analyzer. After 450 h, a maximum compressive stress of 120 MPa was reached. Power loss up to 300% was observed, while magnetic susceptibility dropped by 35%. The magneto-mechanical effect on core losses was simulated with the Hodgdon–Esguerra hysteresis model, showing excellent agreement with tested results, which allows us to predict the behavior of ferrite tiles embedded in load-bearing surfaces for wireless power transfer (WPT) applications.
Ultra-wideband radar cross section reduction achieved by an absorptive coding metasurface
Authors: Lin Baoqin , Huang Wenzhun , Guo Jianxin , Wang Zuliang , Si Kaibo , Zhu Rui
Published: May 2024

An absorptive coding metasurface (ACM) is proposed to achieve radar cross section (RCS) reduction in this paper. In the design progress of the ACM, two different lossy coding elements are proposed at first, which can both be regarded as a composite composed of a two-layer resistive frequency selective surface (RFSS) and a polarization conversion metasurface (PCM). The two-layer RFSS has a certain wave-absorbing property due to ohmic loss. In addition, the PCM can achieve ultra-wideband linear polarization conversion, and the polarization-converted reflected waves in the two coding elements under the same incidence will differ by nearly 180° in phase because the sub-unit-cell structures in them are perpendicular to each other. Thus, based on the two lossy coding elements, the ACM is proposed, which can achieve ultra-wideband RCS reduction due to absorption and phase cancelation. Numerical simulations demonstrate that the RCS of the ACM under normal incidence can be reduced more than 10 dB in the ultra-wide frequency band from 6.9 to 41.2 GHz with a relative bandwidth of 142.6%. Moreover, it has the advantages of polarization-insensitivity and wide incident angle. Finally, one effective experimental verification is carried out, and a reasonable agreement is observed between the simulation and experimental results.
Generation of intense, polarization-controlled magnetic fields with non-paraxial structured laser beams
Authors: Martín-Domene Sergio , Sánchez-Tejerina Luis , Martín-Hernández Rodrigo , Hernández-García Carlos
Published: May 2024

The ability to spatially separate the electric and magnetic fields of a light beam enables the inspection of laser–matter interactions driven solely by optical magnetic fields. However, magnetic field excitations are commonly orders of magnitude weaker than those driven by the electric field. Several studies have already demonstrated the isolation of an intense, linearly polarized magnetic field using structured light. In this work, we report the generation of isolated high intensity magnetic fields with controlled polarization state in the non-paraxial regime using structured laser beams. Our theoretical findings highlight a significant enhancement in the amplitude of the longitudinal magnetic field carried by an azimuthally polarized laser under tight-focusing conditions. Furthermore, by implementing a multiple-beam configuration, we achieve precise control over the polarization state and amplitude of the spatially isolated magnetic field. We report the generation of polarization-controlled magnetic fields reaching up to tens of Tesla, even from moderately intense laser beams of ∼1012 W/cm2. Our study paves the way for ultra-intense interactions with circularly polarized magnetic fields from a feasible experimental setup point of view, particularly interesting to probe ferromagnetic materials and chiral media.
Quasi-one-dimensional electron gas for ultrahigh sensitivity of ambient light
Authors: Liu Zhenqi , Wang Lin , Tong Tong , Xu Hang , Xue Yue , Qi Yaping , Gao Ju , Ma Chunlan , Jiang Yucheng
Published: May 2024

Two-dimensional electron gas (2DEG) has drawn significant attention due to its intriguing properties. Recent advances have encouraged the use of one-dimensional electron gas for high-performance functional devices. Here, we develop a universal method of atomic force microscope tip etching to construct a quasi-one-dimensional (Q1D) channel on the STO surface. Ar+ ion beam is used to bombard the SrTiO3 surface for inducing the Q1D electron gas (Q1DEG). Compared with 2DEG, Q1DEG exhibits a significant enhancement in terms of photoconductivity. At room temperature, it exhibits ultrahigh sensitivity to ambient light with increase in photocurrent by over five orders of magnitude. A slow response to the ON/OFF light indicates persistent photoconductivity (PPC), originating from the defect levels. Furthermore, we investigate the wavelength dependence of PPC in Q1DEG. It is found that decreasing wavelength favors photoresponsivity and prolongs the response time. Based on the electron diffusion process in the oxygen-deficient region, a mechanism has been proposed to explain the advantages of Q1DEG over 2DEG in regard to photoelectric response. This work paves a path for the development of high-performance photoelectric devices based on Q1D electronic systems.
Unraveling the collinearity in short-range order parameters for lattice configurations arising from topological constraints
Authors: Chatterjee Abhijit
Published: May 2024

In multicomponent lattice problems, for example, in alloys and at crystalline surfaces and interfaces, atomic arrangements exhibit spatial correlations that dictate the kinetic and thermodynamic phase behavior. These correlations emerge from interparticle interactions and are frequently reported in terms of the short-range order (SRO) parameter. Expressed usually in terms of pair distributions and other cluster probabilities, the SRO parameter gives the likelihood of finding atoms/molecules of a particular type in the vicinity of other atoms. This study focuses on fundamental constraints involving the SRO parameters that are imposed by the underlying lattice topology. Using a data-driven approach, we uncover the interrelationships between different SRO parameters (e.g., pairs, triplets, and quadruplets) on a lattice. The main finding is that while some SRO parameters are independent, the remaining are collinear, i.e., the latter are dictated by the independent ones through linear relationships. A kinetic and thermodynamic modeling framework based on these constraints is introduced.
Study of energy dissipation mechanisms and hotspot formation patterns during impact process in octogen explosives with circular cavities
Authors: Li Shuai , Si Yingming , Meng Baoqing , Tian Baolin
Published: May 2024

Considerable focus has been given to hotspot generation and ignition phenomena in impact-induced explosives. Hotspot formation in explosives is typically attributed to internal dissipation and heat transfer occurring within them. This study refines the momentum and energy equations to illustrate the entire process of particle collision, temperature-rise evolution, and hotspot formation in octogen explosive bed under impact. By octogen, we mean the substance known as cyclotetramethylene tetranitramine, which is also commonly referred to as HMX. Dense particles are considered to have pseudo-fluid properties. During the impact of the explosive, we captured the propagation of the stress wave and compared its similarities and differences with the shock wave. The collision force model incorporates a combination of Hertz–Mindlin elastic and Thornton elastoplastic contact theories. The temperature-governing equation includes sliding friction, rolling resistance, and plastic dissipations as energy sources, taking into account the heat transfer processes between particles. Temperature evolution is a spatiotemporally correlated phenomenon divided into three processes: high-temperature bands formation, cavity collapse, and particle bed dispersion, all of which lead to hotspot formation near the cavity and near the wall. Plastic dissipation is the primary source for particle temperature-rise and hotspot formation. Furthermore, the effect of cavity size, impact velocity, and particle size on temperature evolution and hotspot formation patterns is analyzed. It was found that higher impact velocities and smaller cavity sizes are associated with increased hotspot temperatures near the wall, but the hotspot temperature near the cavity does not consistently vary with impact velocity and cavity size. This is attributed to the relationship between energy dissipation rate and void collapse time.
Investigation of the buoyancy effect on the thermoacoustic instability in an electrically heated Rijke tube
Authors: Liu Jiale , Pang Bosheng , Wang Teng , Yang Lijun , Li Jingxuan
Published: May 2024

Thermoacoustic instability typically presents in the operation of various engines and is harmful. It is thus necessary to investigate the influence mechanisms on it. When the effect of natural convection caused by buoyancy is equivalent to that of forced convection, the buoyancy effect will have a significant effect on the thermoacoustic instability. In order to study these effects, an electrically heated Rijke tube with adjustable pitch angle was designed. By adjusting the pitch angle under different operating conditions, the instability map as the functions of flow rates and heating powers was obtained. As the temperature field within the Rijke tube varies greatly at different pitch angles, its effect was also investigated associated with the numerical simulation. The results showed that the growth rates of the thermoacoustic instability exhibited a sinusoidal-like dependence on the pitch angle under certain operating conditions. This variation relationship only occurs when the Richardson number is sufficiently large.
Investigation of triangularity impact on impurity content in JET-ILW H, D, T, and DT plasmas
Authors: Gromelski Wojciech , Angioni Clemente , Chomiczewska Agata , Fajardo Daniel , Ivanova-Stanik Irena , King Damian , Kowalska-Strzęciwilk Ewa , Maslov Mikhail , Pawelec Ewa , Schneider Philip ,   EUROfusion Tokamak Exploitation Team,   JET Contributors
Published: May 2024

The work presents the recent outcome of the research on Joint European Torus with ITER-like wall (JET-ILW) concerning Be, mid-Z (Ni, Cu, Fe), and high-Z (W) impurities for a selection of Neutral Beam Injection-heated, ELMy H-mode pulses using visible and vacuum–ultraviolet spectroscopy together with bolometry diagnostic. The investigation is focused on the evaluation of the plasma triangularity (δ) impact on the impurity radiation in hydrogen (H), deuterium (D), tritium (T), and deuterium–tritium (DT) plasmas for pulses described in [P. A. Schneider, Nucl. Fusion 63, 112010 (2023)]. The variations of δ were in the range of 0.21–0.31 for different time windows with low magnetic toroidal field (Bt=1.7 T) and plasma current (Ip=1.4 MA) in the corner–corner configuration, that is with both the inner and outer strike points on the horizontal W-coated divertor target plates. The results confirm the rise in Be flux with plasma isotope and lower δ leading to higher plasma density close to the plasma wall. The dominant role of W as a source of plasma radiation has also been confirmed. For mid-Z impurities and W, the variations in their densities due to δ change are negligible and the rise in their densities is observed with higher isotope mass, although this effect is often masked by the dominant role of ELM frequency on the impurity level. The impurity radiation losses based on bolometry together with the W intensity are ruled by the changes in the electron density and are well correlated when the Te profiles are conserved.
Using entropy balance to determine multiphase flow distribution in thermally decoupled parallel channels with shared inlet and outlet headers
Authors: Aka Toochukwu , Narayan Shankar
Published: May 2024

Multiphase flow with boiling in parallel channels is often an efficient approach to managing heat and energy distribution in several engineering systems. However, two-phase flow with heating in parallel channels is prone to maldistribution, which can result in sub-optimal performance and, in some cases, permanent damage to the system. This challenge requires accurate flow modeling in parallel channels to mitigate or design against the adverse effect of two-phase flow maldistribution. The nonlinear nature of the multiphase flow model can yield multiple solutions for the same operating condition, creating significant challenges in predicting flow distribution. This study addresses this challenge by applying the entropy balance analysis and the conservation of mass, momentum, and energy to predict two-phase flow distribution in two thermally isolated parallel channels with a numerical model. Our model predictions and experiments show that equally distributed flow can become severely maldistributed with a decrease in flow rate, accompanied by a significant (>30%) change in the entropy generation rate. We show that the entropy balance analysis can distinguish between stable and unstable flows and identify the most feasible flow distribution in thermally decoupled parallel channels.
Negative spin polarization of Mn2VGa Heusler alloy thin films studied in current-perpendicular-to-plane giant magnetoresistance devices
Authors: Suto Hirofumi , Barwal Vineet , Simalaotao Kodchakorn , Li Zehao , Masuda Keisuke , Sasaki Taisuke , Miura Yoshio , Sakuraba Yuya
Published: May 2024

Magnetic materials with high negative spin polarization have been sought as a building block to increase the design freedom and performance of spintronics devices. In this paper, we investigate negative spin polarization of Mn2VGa Heusler alloy in current-perpendicular-to-plane giant magnetoresistance (CPP-GMR) devices. We fabricated an epitaxial CPP-GMR stack consisting of Mn2VGa/Ag/CoFe with L21 ordering in the Mn2VGa layer and observed negative magnetoresistance (MR), which provided evidence of negative spin polarization. The MR ratio depended on thermal treatments (deposition at an elevated temperature and post-annealing), because these processes affected the ordering, roughness, and magnetic properties of Mn2VGa. The maximum MR ratio reached −1.8% at room temperature and −3.0% at low temperatures, representing the highest among the negative MR values in pseudo-spin-valve CPP-GMR devices despite the underestimation due to an incomplete antiparallel magnetization configuration. These findings demonstrate the potential of Mn2VGa for a material with high negative spin polarization.
Thickness-dependent topological domain textures of layered ferroelectric Bi2WO6 thin films
Authors: Kwon Yong-Jun , Yang Chan-Ho
Published: May 2024

Topological polar structures are attracting attention as potential applications of next-generation high-density memories. We investigate how the ferroelectric domain evolves with film thickness in c-axis oriented epitaxial Bi2WO6 thin films grown on (LaAlO3)0.3(Sr2AlTaO6)0.7 substrates. In addition to the general thickness scaling effect on domain size, we find that 3- or 4-variant domains appear in a sample thicker than 120 nm, whereas ⟨100⟩-type domains compete with the ⟨110⟩ ones in thinner samples, resulting in a variety of nontrivial topological structures. By visualizing the spatial distribution of electric polarizations through angle-resolved piezoresponse force microscopy, we provide direct evidence for the spontaneous emergence of nontrivial topological polar structures. These results provide useful insights into the domain behavior of layered ferroelectric thin films.
Effect of turbulent integral scale on non-Gaussian characteristics of surface wind pressure on square cylinder
Authors: Yang Xiongwei , Su Yi , Li Mingshui , Jiang Zhiyuan , Du Shubi
Published: May 2024

This study investigated the statistical properties of the pressure fluctuations on a square cylinder across three distinct turbulence fields characterized by varying turbulent integral scales. The effect of turbulent integral scale on the non-Gaussian characteristics and extreme surface wind pressure acting on square cylinders beneath the separating flow were studied in detail. The findings indicated that the pressure distribution on the windward surface generally conformed to a Gaussian distribution, whereas notable non-Gaussian characteristics were observed in the pressure distribution on the side and leeward surfaces. The fluctuating pressure, skewness, kurtosis, peak factor, and extreme pressure increase with an increasing ratio of turbulent integral scale to structural depth (Lux/D), whereas the mean pressure remains unaffected by variations in Lux/D. As Lux increased, the energy of the internal vortices in the shear layer also increased. As a result, the non-Gaussian features of the pressure caused by vortex breakdown become more pronounced. Compared with Lux/D = 1.96, the underestimated value of the extreme pressure on the square cylinder had a maximum difference of up to 15.4% at Lux/D = 0.53. Therefore, the corresponding turbulent integral scale should be accurately simulated when measuring wind loading on a structure through wind tunnel tests.
A phytoplasma effector destabilizes chloroplastic glutamine synthetase inducing chlorotic leaves that attract leafhopper vectors
Authors: Zhang Xiao-Feng , Li Zhanpeng , Lin Hanbin , Cheng Yu , Wang Huanqin , Jiang Zhoumian , Ji Zhenxi , Huang Zhejun , Chen Hongyan , Wei Taiyun
Published: May 2024

Leaf yellowing is a well-known phenotype that attracts phloem-feeding insects. However, it remains unclear how insect-vectored plant pathogens induce host leaf yellowing to facilitate their own transmission by insect vectors. Here, we report that an effector protein secreted by rice orange leaf phytoplasma (ROLP) inhibits chlorophyll biosynthesis and induces leaf yellowing to attract leafhopper vectors, thereby presumably promoting pathogen transmission. This effector, designated secreted ROLP protein 1 (SRP1), first secreted into rice phloem by ROLP, was subsequently translocated to chloroplasts by interacting with the chloroplastic glutamine synthetase (GS2). The direct interaction between SRP1 and GS2 disrupts the decamer formation of the GS2 holoenzyme, attenuating its enzymatic activity, thereby suppressing the synthesis of chlorophyll precursors glutamate and glutamine. Transgenic expression of SRP1 in rice plants decreased GS2 activity and chlorophyll precursor accumulation, finally inducing leaf yellowing. This process is correlated with the previous evidence that the knockout of GS2 expression in rice plants causes a similar yellow chlorosis phenotype. Consistently, these yellowing leaves attracted higher numbers of leafhopper vectors, caused the vectors to probe more frequently, and presumably facilitate more efficient phytoplasma transmission. Together, these results uncover the mechanism used by phytoplasmas to manipulate the leaf color of infected plants for the purpose of enhancing attractiveness to insect vectors.
Searches for compact binary coalescence events using neural networks in LIGO/Virgo third observation period
Authors: Menéndez-Vázquez A , Andrés-Carcasona M , Martínez M , Mir Ll M
Published: May 2024

We present the results on the search for the coalescence of compact binary mergers using convolutional neural networks (CNNs) and the LIGO/Virgo data for the O3 observation period. Two-dimensional images in time and frequency are used as input. The analysis is performed in three separate mass regions covering the range for the masses in the binary system from 0.2 M

⊙

to 100 M

⊙

, excluding very asymmetric mass configurations. We explore neural networks trained with input information from pairs of interferometers or all three interferometers together, concluding that the use of the maximum information available leads to an improved performance. A scan over the O3 data set, using the CNNs, is performed with different false rate thresholds for claiming detection of at most one event per year or at most one event per week. The latter would correspond to a loose online selection still leading to affordable false alarm rates. The efficiency of the neutral networks to detect the O3 catalog events is discussed. In the case of a false rate threshold of at most one event per week, the scan leads to the detection of about 50% of the O3 catalog events. Once the search is limited to the catalog events within the mass range used for neural networks training, the detection efficiency increases up to 70

%

. Further improvement in search efficiency, using the same type of algorithms, will require the implementation of new criteria to suppress the remaining major background sources.
Kinetically anisotropic Hamiltonians: plane waves, Madelung streamlines and superpositions
Authors: Berry M V
Published: May 2024

A Hamiltonian in two space dimensions whose kinetic-energy contributions have opposite signs is studied in detail. Solutions of the time-independent Schrödinger equation for fixed energy are superpositions of plane waves, with wavevectors on hyperbolas rather than circles. The local velocity (e.g. in the Madelung representation) is proportional to the kinetic momentum, i.e. local particle velocity, not the more familiar canonical momentum (phase gradient). The patterns of the associated streamlines are different, especially near phase singularities and phase saddles where the kinetic and canonical streamline patterns have opposite indices. Contrasting with the superficially analogous circular smooth solutions of kinetically isotropic Hamiltonians are wave modes that are anisotropic in position and also discontinuous. Pictures illustrating these phenomena are included. The occurrence of familiar concepts in unfamiliar guises could be useful for teaching quantum or wave physics at graduate level.
Research on the stability prediction for multi-posture robotic side milling based on FRF measurements
Authors: Song Ci , Liu Zhibing , Wang Xibin , Qiu Tianyang , Liang Zhiqiang , Shen Wenhua , Gao Yuhang , Ma Senjie
Published: May 2024

In robotic side milling, frequent chatter extremely restricts the acquisition of high surface quality due to weak stiffness, and cutting parameters optimization guided by stability boundary is regarded as an effective solution to solve the chatter problem. In this research, the influence mechanisms of stability were analyzed by evaluating the structural static stiffness and dynamic parameters, and the main factor was characterized as regenerative chatter by means of stability measurements and the theoretical prediction model. The distance-driven multi-posture frequency response function (FRF) prediction model was improved in terms of the dominant modal. Grey correlation analysis was carried out to investigate the influence law of robotic joints to modal parameters, and the difference between far-distance posture and near-distance posture was re-characterized by cross-validation of FRF measurements. Finally, the third-order Hermite–Newton approximation was employed to solve the dynamic model by considering process damping effect, and the results showed the prediction accuracy of the constructed stability boundary was over 85%.
Prediction model of bearing fault remaining useful life based on weighted variable loss degradation characteristics
Authors: Yu Tianyi , Li Shunming , Lu Jiantao
Published: May 2024

In the prediction of bearing fault remaining useful life (RUL), the identification and feature extraction of early bearing faults are very important. In order to improve the accuracy of early fault RUL prediction, a bearing fault RUL prediction model based on weighted variable loss degradation characteristics is proposed. The model is composed of a stack denoising autoencoder (SDAE) module guided by variable loss, a signal-to-noise feature adaptive weighting module and a long-short term memory (LSTM) degradation characteristics extraction and regression output module. Firstly, this model improves the ability of SDAE model to extract weak fault features by ascending dimension learning and variable loss function. Then, an adaptive weighting matrix is generated according to the test signal to modulate the weight vector of SDAE. Finally, the hidden layer features of SDAE were input into LSTM model to extract the bearing state degradation features and realize the RUL prediction of bearing faults. The experimental results show that the proposed model can accurately predict the RUL of the test data in the early fault stage and the fault development stage. The proposed model can give early fault warning to the bearing state.
A data fusion-based approach for structural damage detection with distributed long-gauge strain measurements
Authors: Zhou Zhenwei , Ding Kaiqing , Fang Wangwang , Sheng Wang , Yanchao Shao , Wu Bitao
Published: May 2024

Distributed long gauge strain sensing technology has solved the problem of difficult identification of local damage in traditional ‘point’ monitoring, and has received extensive attention in the field of structural damage identification. Owing to the inevitable presence of measurement noise and environmental factors in the macro strain response measurement, a single damage index has also underlined some drawbacks generally arising when multiple damages occur, or errors affect the identified dynamic properties of the systems. To address these challenges, this paper proposes a data fusion method based on the Dempster–Shafer evidence theory, relying on distributed strain sensing technology. The identification results of the modal macro strain-based index and quasi-static macro strain energy-based damage index are fused to make a comprehensive decision on structural damage location. Damage identification studies are conducted on different types of structures under impact loads and random wind loads to verify the effectiveness and accuracy of the proposed data fusion method in the case of single and multiple damage conditions. The results show that the proposed data fusion method can accurately identify the damage location and effectively reduce misjudgment on undamaged locations; it has potential application value in practical structural health monitoring.
Design and construction of an affordable optical power meter: micro- to milli-Watt in the 400–800 nm range
Authors: dos Santos Jr Juracy L , Andrade Ian R , Silva Lucas H P , Abegão Luis M G
Published: May 2024

This study introduces the design, construction, and evaluation of an affordable optical power meter prototype, AYR (Affordable Yet Reliable) version 1.0, which operates effectively within the 400–800 nm range, using a silicon photodiode. Aimed at bridging the gap in accessibility to precise and reliable photonics instrumentation, especially in resource-constrained settings, AYR 1.0 leverages advancements in photodiode technology, additive manufacturing, and do-it-yourself electronics. The device incorporates a custom-built electronic circuit that facilitates accurate optical power measurement by converting light into electrical current. Through rigorous testing against a reliable commercial optical power meter, AYR 1.0 demonstrated exceptional accuracy and reliability. Sensitivity values ranged from ∼13 μA mW−1 at 405 nm to ∼796 μA mW−1 at 805 nm. The operational power range spanned from 0.003 mW to 242.0 mW, with linearity (R
2) values consistently above 0.9981, indicating high fidelity in measurement. Repeatability percentages varied between 99.4% and 99.9%, and response times ranged up to 55 μs, showcasing the prototype’s rapid and reliable response to changes in optical power. The key components include a low-cost silicon photodiode (2DU10), a differential trans-impedance amplifier circuit for signal processing, and a 3D-printed housing for the sensor head and console, contributing to its cost-effectiveness and robustness. The prototype’s total cost was 116 US dollars, highlighting its affordability and potential for widespread adoption.
A new two-dimensional, spiropyran-based polymer fluorescent nanoprobe with quantitative-fluorescent and photochromic properties for multi-substance detection
Authors: Lin Riyan , Zhang Hefeng , Huang Yifu
Published: May 2024

One challenge of the structural design of a fluorescent probe is how to improve the detection performance on trace target analytes in complex samples. Herein a new polymer fluorescent nanoprobe (2DSP-C28) has been synthesized, by adopting a two-dimensional (2D), spiropyran (SP)-based nanosheet structure with hydrophobic long-chain alkanes (C28). Unlike a traditional SP-based small molecule probe, the 2DSP-C28 probe can exhibit quantitative-fluorescent and photochromic properties. Under the detection of metal-ions, the nanoprobe in dimethyl sulfoxide aqueous solution is selectively fluorescent-quenched-responsive for Fe-ions (∼100 μM), with a characteristic stoichiometric ratio of <10, a high sensitivity (limit of detection: ∼0.2 μM). When the nanoprobe is incorporated into electrospun polyethylene oxide, it can be used for gas detection, and display a color-change with acid-base gas and identify the HF gas. It is expected that this new polymer fluorescent nanoprobe can be promisingly applied for rapidly environmental monitoring on the ion or gas pollution.
Low field anomaly in the critical current of Ba1−
x
K
x
Fe2As2 tapes
Authors: Strickland Nicholas M , Chong Shen , Dong Chiheng , Zhang Xianping , Ma Yanwei , Jiang Zhenan
Published: May 2024

Ba1−x
K
x
Fe2As2 superconductors have strong potential for magnet applications through their very high upper critical field, relatively high superconducting transition temperature and manufacturability through the powder-in-tube (PIT) route. However, the critical current density in PIT tapes is still low compared to the incumbent technologies, so a greater understanding of the limiting factors is required. We have measured the in-field critical currents (I
c) of stainless steel and silver double-sheathed monofilament Ba0.6K0.4Fe2As2 superconductor tapes at elevated temperatures from 15 K to 35 K. At 20 K, the critical current density is up to 140 kA cm−2 in low (optimal) field and 22 kA cm−2 in 8 T. In the low-field region we observe an anomalous and sharp suppression of I
c centred at the zero field. This feature is non-hysteretic for lower temperatures and perpendicular fields, but becomes hysteretic for higher temperatures in perpendicular fields and for all temperatures in parallel fields. The low-field suppression is also reflected in the n-values which can otherwise be very high, in excess of 100 in the optimal field. Magnetic-field hysteresis of I
c is generally attributed to flux exclusion/flux trapping in granular superconductors and this is likely to be the case also in the present conductors. The low-field I
c anomaly also likely has its origin in planar granularity, while magnetic phases in grains or grain boundaries may also play a role.
FE/PDE: a novel approach applied to PC plate structure with multi-scale and multi-physics field coupling
Authors: Qian Denghui , Liu Guoqing
Published: May 2024

For the more straightforward and more efficient solution of phononic crystal (PC) plate frequency band structure, transmission curve, and vibration mode, in this paper, related theories based on spatial Fourier series expansions, combined with Bloch’s theorem, a novel approach to solve the structural governing equations of PC plate is proposed by using the partial differential equations (PDE) module in the finite element software COMSOL. It is named the FE/PDE (Finite element and partial differential equations) method. The method’s accuracy is verified by comparing the results with those obtained from the traditional method. Systematic elucidation of the application of the method to probe the properties of multi-scale, multi-physics field coupled PC plate. In order to demonstrate the flexibility and scientific validity of the method, a novel nano-piezoelectric PC plate structure is proposed and solved. The method is simple, computationally efficient, and applicable, and provides a new method for investigating the properties of PC plates.
Optimization and analysis of apodized fiber Bragg grating properties for quasi-distributed sensing
Authors: Mandal Himadri Nirjhar , Sidhishwari Soumya
Published: May 2024

An apodized fiber Bragg grating (FBG) is introduced with a proposed apodization function for the effective quasi-distributed sensing estimation of the temperature and the strain. FBG features such as reflectivity, side lobes, and bandwidth have been optimized for the designed apodized grating to upgrade the effectiveness of FBG for properly measuring the variations in the Bragg wavelength. Based upon the simulation, a comparative analytical study on FBG properties with different apodization function profiles has been demonstrated to achieve the optimum profile with high reflectivity, narrow bandwidth and minimal range of side lobes for quasi-distributed sensing estimation of parameters. A strong linearity has been noted for the sensitivity of designed FBG with different apodization profiles for the temperature and the strain estimation subsequently. It has been reported that the obtained sensitivity of measurands for the FBG with proposed apodization profile are higher as compared with the other profiles. The wavelength division multiplexing (WDM) based quasi-distributed network of four optimized FBGs have been implemented for different apodization profiles to illustrate the impact of apodization to prevent overlapping between neighbouring FBG spectrums in the sensing network with spatial resolution of 2 nm. The maximal detectable temperature/strain sensitivity estimation of 153 °C/1439 μϵ have been obtained for the proposed apodized FBG along with minimal detectable temperature/strain ranges of −102 °C/−1345 μϵ in the quasi-distributed network. The achieved ranges with optimum resolution can be implemented effectively in quasi-distributed based sensing application for condition observation of civil infrastructures in any complex circumstances.
Detailed Monte Carlo simulations on secondary radiation emissions of polymer based neutron shielding materials
Authors: Korkut Hatun , Korkut Turgay
Published: May 2024

Since radiation safety is a sensitive issue in terms of health, this situation poses a significant problem. In order to raise awareness among researchers while preparing future studies on this problem, in this study, the interactions between fast neutrons and 10 different polymer-based shielding materials determined from the literature were modeled with the GEANT4 Monte Carlo code. The fast neutron shielding performances of the samples and the emitted secondary radiation and radioactivity have been reported. When evaluated number and mean energies of created particles, in order to solve this problem, the sum of the risk factors obtained by multiplying these values for each sample can provide us with the opportunity to make a more accurate evaluation. When these values are examined, sample P9 is at the top of the risk ranking with a value of 1823472, while sample P6 is at the bottom with a value of 146246. As a result, it has been revealed that these samples, which have good fast neutron shielding properties, also produce high levels of radiation and radioactive nuclei.
Realisation of the triple-point of Argon: comparison between two devices
Authors: Lopardo G , Dematteis R , Steur P P M
Published: May 2024

A new cryostat for the realization of the triple-point of the argon (83.8058 K), a defining fixed point of the International Temperature Scale of 1990 (ITS-90), was acquired at Italian National Metrological Institute (INRiM). The new system, manufactured by Fluke, is intended to substitute the current National reference, a model developed at BNM-INM in the 1975. The main difference between the two system is in the way to control the temperature. In the BNM-INM device the temperature is controlled adjusting the pressure of liquid nitrogen bath, in the Fluke system instead, an electrical heater wrapped around the argon cell is used, following cryogenic practice. This paper describes the result of the direct comparison and shows typical phase transitions obtained with the two argon systems. Then, a complete uncertainty budget is evaluated for the new Fluke system and compared with the National standard.
Fidelity and entanglement of random bipartite pure states: insights and applications
Authors: Biswas George , Hu Shao-Hua , Wu Jun-Yi , Biswas Debasish , Biswas Anindya
Published: May 2024

We investigate the fidelity of Haar random bipartite pure states from a fixed reference quantum state and their bipartite entanglement. By plotting the fidelity and entanglement on perpendicular axes, we observe that the resulting plots exhibit non-uniform distributions. The distribution depends on the entanglement of the fixed reference quantum state used to quantify the fidelity of the random pure bipartite states. We find that the average fidelity of typical random pure bipartite qubits within a narrow entanglement range with respect to a randomly chosen fixed bipartite qubit is

1

4

. Extending our study to higher dimensional bipartite qudits, we find that the average fidelity of typical random pure bipartite qudits with respect to a randomly chosen fixed bipartite qudit remains constant within a narrow entanglement range. The values of these constants are

1

d

2

, with d being the dimension of the local Hilbert space of the bipartite qudit system, suggesting a consistent relationship between entanglement and fidelity across different dimensions. The probability distribution functions of fidelity with respect to a product state are analytically studied and used as a reference for the benchmarking of distributed quantum computing devices.
Low-frequency broadband valley transport for acoustic topology based on extended resonance
Authors: Liang Xiao , Luo Jiangxia , Chu Jiaming , Liang Haofeng , Meng Daxiang , Zhang Zhi
Published: May 2024

This paper proposes an extended resonant structure to solve the problem that topological acoustic waveguides have a narrow bandwidth at low frequencies. This acoustic structure consists of a two-dimensional structure and a resonant cavity in the three-dimensional direction, and its essence is to extend the resonant cavity in the two-dimensional structure to the three-dimensional direction. The problem that the size of the resonant cavity is limited by the size of the two-dimensional structure can be solved by this special extension. At the same time, the resonant cavity can be maximized in the three-dimensional direction. The topological properties of the original structure are not affected as long as the radius of the resonant cavity is widened without changing the symmetry of the overall composite structure. The rotating scatterer remains a reliable method for realizing topological phase transitions. The effect of the resonant cavity length on the band position is obtained using the finite element method, and it is demonstrated that the topological acoustic waveguide has a wide operating band at low frequencies. Simulation results show that this structure still has a bandgap width of 100 Hz at a low frequency of 350 Hz. The topological acoustic waveguide structure proposed in this paper can provide a new idea for the study of low-frequency broadband acoustic topology, which promotes the control of low-frequency acoustic waves by the topological acoustic waveguide.
Leaky wave antenna loaded complementary elements with dual-stopband suppression
Authors: Chen Junjiang , Su Jinlong , Hu Fei
Published: May 2024

In this paper, a periodic leaky wave antenna (PLWA) using complementary elements is proposed. The complementary elements of the transverse slot (horizontal magnetic current) and the monopole pairs (vertical electric current) in the substrate integrated waveguide (SIW) is employed as the radiation element, which can simultaneously suppress closed stopband β
0
p = π and open stopband (OSB) β

−1
p = 0 to enhance the forward scanning of the LWA. Additionally, the gain and cross-polarization of the element are improved due to the loading of the monopole pairs. The LWA achieves forward and backward scanning from −73° to 10° when operating at the n = −1 spatial harmonic (SH), with corresponding gains of 11.5 to 15.4 dBi. When operating at the n = 0 SH, it achieves forward scanning from 58° to 72°, with corresponding gains of 5.2 to 7.5 dBi. Moreovere, due to the element and its symmetrical structure, the cross-polarization within the entire operating frequency range is less than −35 dB. The design concept is validated through processed, fabricated, and tested.
Enhanced Blandford Znajek jet in loop quantum black hole
Authors: Jiang Hong-Xuan , Dihingia Indu K. , Liu Cheng , Mizuno Yosuke , Zhu Tao
Published: May 2024

The Blandford-Znajek (BZ) process powers energetic jets by extracting the rotating energy of a Kerr black hole. It is important to understand this process in non-Kerr black hole spacetimes. In this study, we conduct two-dimensional and three-dimensional two-temperature General Relativistic Magnetohydrodynamic (GRMHD) simulations of magnetized accretion flows onto a rotating Loop-Quantum black hole (LQBH). Our investigation focuses on the accretion flow structure and jet launching dynamics from our simulations. We observe that the loop quantum effects increase the black hole angular frequency for spinning black holes. This phenomenon intensifies the frame-dragging effect, leading to an amplification of the toroidal magnetic field within the funnel region and enhancement of the launching jet power. It is possible to fit the jet power following a similar fitting formula of the black hole angular frequency as seen in the Kerr black hole. Based on the General Relativistic Radiation Transfer (GRRT) calculation, we find that the jet image from LQBH has a wider opening angle and an extended structure than the Kerr BH.
Study on structural and material dependence of Rhodium Self-powered Neutron Detector performance
Authors: Wan Bo , Li Gang , Li Kun , Li Dan , Huang Qichang , Xia Yuan , Wei Wenbin , Luo Ying , Wang Miao , Yang Daibo
Published: May 2024

The neutron measurement properties of Rh-SPNDs are greatly
affected by their geometric constructions, which needs to be
optimized while designing. This effect is reflected in the
sensitivities for gamma and neutron detection. However, the
influence on gamma sensitivity has not been fully analyzed before,
which is of the same importance as neutron sensitivity. Therefore,
it is necessary to quantitatively analyze the relationship between
detector sensitivity and geometric dimensions. The effect of Rh-SPND
structural and material parameters on neutron and gamma
sensitivities has been calculated and analyzed through numerical
simulations. The research results show that detector sensitivities
are strongly depending on the detector size and its emitter
shape. Moreover, the detector response to exogenous reactor gamma
can be eliminated by optimizing the detector collector size.
Impacts of stratosphere-to-troposphere transport on tropospheric ozone in southeastern China: insights from ozonesonde observations
Authors: Hong Jin , Wang Hongyue , Wang Wuke , Zhu Jintao , Deng Huiying , Wang Hong
Published: May 2024

Tropospheric ozone pollution poses a major environmental challenge in China. As its primary natural source, Stratosphere-to-Troposphere Transport (STT) has been recognized as a significant contributor to tropospheric ozone in western, northeastern, and eastern China. However, the extent of STT’s influence on southeastern China has been less studied due to data limitations. Using a recently available one-year dataset of ozonesonde observations from a regional background station, we find that STT contributes significantly to tropospheric and surface ozone elevation in southeastern China. Our results show that STT plays a more substantial role in shaping tropospheric ozone during spring than previously believed, accounting for over 30% of ozone concentrations above 4 km. Without the stratospheric contribution, the spring seasonal peak almost disappears. STT can also significantly influence ozone concentrations at the surface. For example, a distinct ozone profile was observed on 4 May 2022, with a notable increase in tropospheric ozone. This tropospheric ozone increase was caused by a STT event triggered by a robust horizontal trough and subsequent southward movement of subtropical jets in the upper troposphere. According to a stratospheric tracer derived from an atmospheric chemistry model, this STT event contributed to 25%–30% of the surface ozone increase. Overall, this study highlights the important role of STT in driving tropospheric ozone variations, even in regions with comparatively lower ozone levels in southeastern China.