bluuebunny/crossref_metadata_2025 huggingface dataset:
Classical vs generalized Kirchhoff's law in anisothermal structures
Authors: Boudan G. , Eustache E. , Garabedian P. , Messina R. , Ben-Abdallah P.
Published: March 2024

We quantitatively analyze the thermal emission by anisothermal structures. By comparing the heat flux radiated by simple multilayered systems calculated using the classical Kirchhoff's law to the exact flux derived from a fluctuational-electrodynamics theory, we highlight the limits of validity of the radiometric theory to predict the thermal emission with respect to the geometric configuration, the temperature gradient, and the type of materials and also highlight discrepancies as high as 50%.
Turbulent drag reduction in compressible flows using streamwise traveling waves
Authors: Ahmad Moghees , Baig M. F. , Anwer S. F.
Published: March 2024

Skin-friction drag reduction (DR) in supersonic turbulent channel flows using streamwise traveling waves of spanwise velocity (STWSV) has been studied using direct numerical simulations. In the present study, simulations are carried out for different phase speeds of the upstream and downstream traveling waves for a bulk Mach number Mab=1.5 and bulk Reynolds number Reb = 3000. The efficacy of the control has been investigated for other bulk Reynolds numbers as well. The Stokes layer generated by the control affects the near-wall statistics primarily by modifying the coherent structures, thereby either reducing or aggravating the skin-friction drag. For Reb = 3000 and Mab=1.5, a maximum drag reduction (DRmax) of 49% is achieved, primarily due to suppression of sweeps and ejections on application of control. The efficacy of skin-friction drag reduction varies in a small range when Reb is varied from 3000 to 6000; however, the maximum drag reduction is observed for Reb = 4000, owing to a drastic decrease in sweep events. Quadrant analysis reveals that for drag reduction (DR) cases, STWSV reduce magnitude of streamwise u′ and wall-normal w′ velocity fluctuations magnitude and stacks them around zero. In contrast, w′ is increased for drag increase (DI) cases. Skin-friction decomposition using Fukagata, Iwamoto and Kasagi (FIK) identity suggests that the control alters the turbulent component significantly. The behavior of the control is also studied at Mab = 0.3 and 2.5, and it is observed that the maximum drag reduction obtained decreases for high bulk Mach numbers.
Reduction in density of interface traps determined by C-V analysis in III-nitride-based MOSHFET structure
Authors: Hasan Samiul , Jewel Mohi Uddin , Crittenden Scott R. , Zakir Md Ghulam , Nipa Nifat Jahan , Avrutin Vitaliy , Özgür Ümit , Morkoç Hadis , Ahmad Iftikhar
Published: March 2024

An in situ metal-organic chemical vapor phase epitaxy is used to grow a complete AlGaN/GaN metal oxide semiconductor heterojunction field effect transistor (MOSHFET) structure, gated by a gallium oxide (Ga2O3) layer; we observed reduction in the interfacial trap density compared to its version wherein the Ga2O3 was grown ex situ, after breaking the vacuum, all else being the same. A remarkable decrease in the interfacial charge density for in situ MOSHFET structures in the range of 70%–88% for 10–30 nm oxide layer thickness and improvements in other electrical parameters required for high-performing devices were observed.
Simple model for synchronization of two Belousov–Zhabotinsky gels interacting mechanically
Authors: Sukegawa Taro , Yamada Yuhei , Maeda Shingo
Published: March 2024

A Belousov–Zhabotinsky (BZ) gel is a unique biomimetic system that undergoes autonomous volume oscillations induced by the redox oscillation of the BZ reaction. In a previous study, researchers reported that the oscillations of two BZ gels coupled by compression were synchronized by a mechanical interaction. They mathematically explained the synchronization behavior using a phase oscillator model. As a different approach to the previous study, a physicochemical investigation of the phenomenon will lead to a better understanding of the functional biological rhythms essential for life. In this study, we construct a simple phenomenological model to understand the synchronization of BZ gels. The model consists of two parts. One is the dynamics of the chemical reactions in the BZ gels. We use a phenomenological model based on the Oregonator for the BZ reaction. The other is the dynamics of the mechanical deformation of the BZ gel. Using approximations, we extract the parameters essential for the synchronization of a mechanical interaction. Thus, we can derive a novel equation for the deformation dynamics of mechanically coupled BZ gels. By combining these two parts, we perform numerical calculations. This allows us to find that the synchronization of the two BZ gels is less likely to occur under stronger compression. We explain this trend through one physicochemical parameter in our model: the volume fraction of the BZ gel in the reduced state.
On the Painlevé integrability and nonlinear structures to a (3 + 1)-dimensional Boussinesq-type equation in fluid mediums: Lumps and multiple soliton/shock solutions
Authors: Wazwaz Abdul-Majid , Alhejaili Weaam , El-Tantawy S. A.
Published: March 2024

This work examines the Painlevé integrability of a (3 + 1)-dimensional Boussinesq-type equation. Using the Mathematica program, we rigorously establish Painlevé's integrability for the suggested problem. By utilizing Hirota's bilinear technique, we obtain the dispersion relations and phase shifts, which enable us to derive multiple soliton solutions. In addition, we systematically derive a wide range of lump solutions using the Maple symbolic computation. The investigation extends to encompass a variety of exact solutions with distinct structural features, including kink, periodic, singular, and rational solutions. This comprehensive analysis illustrates the profound richness of the model's dynamics and its potential to elucidate diverse nonlinear wave phenomena across various physical contexts. Therefore, the results that we will obtain play a vital role in understanding the mechanism of generation and propagation of many mysterious phenomena that arise in various scientific fields, including plasma physics, fluid mechanics, and the propagation of waves on the surfaces of seas and oceans to optical fibers.
Generation of nearly homogeneous isotropic turbulence using a novel oscillating grid system
Authors: Huang Guangyuan , Lv Xin , Chen Wuguang , Song Yuchen , Yin Junlian , Wang Dezhong
Published: March 2024

The creation and control of homogeneous isotropic turbulence in laboratory settings is of practical significance. In this paper, we propose a novel design for a turbulence generation apparatus driven by two pairs of oscillating grids, with the object of striking a balance between the stochastics of momentum injection and the flexibility of control of turbulent kinematic energy (TKE). To validate the performance of this system, tomographic particle image velocimetry measurements are conducted. Based on Reynolds decomposition, we characterize the secondary flow pattern and examine the impact of the mean velocity on the TKE transport. Analysis of one- and two-point statistics indicates that the generated turbulence exhibits reasonable approximations of homogeneity and isotropy. The TKE and the dissipation rate are linearly proportional to the grid oscillation frequency, with the Taylor-scale Reynolds number Reλ ranging from 47 to 154, suggesting a convenient control of turbulence with low-to-moderate intensity.
Focusing of water waves with a shallow-draft cylinder array
Authors: Zhao Xinyu , Sun Xiaodong , Li Yichen , Hu Xinhua , Che Zhiyuan , Shi Lei , Zi Jian
Published: March 2024

The propagation of water waves can be manipulated via artificial structures. However, such structures usually need to possess a large volume ratio in water, and it may not be easy to build and move them in practical ocean engineering. Here, we theoretically propose and experimentally demonstrate a fixed, shallow-draft cylinder array that can refract and focus water waves within a wide range of wavelengths. When impinging upon the cylinder array from a region of water without structures, water waves can be slightly reflected at the surface of the array and speeded up in the array. As a result, favorable focusing performances such as a short focal length and high intensity at the focal point are observed.
Pressure-induced ferroelectric and electronic transitions in two-dimensional ferroelectric semiconductor of NbOCl2 up to 41.7 GPa
Authors: Hong Meiling , Dai Lidong , Hu Haiying , Zhang Xinyu , Li Chuang
Published: March 2024

NbOCl2, a representative van der Waals ferroelectric (FE) semiconductor, has become the research frontier due to its peculiar appeal in both fundamental research studies and potential applications. In the present work, the high-pressure structural, vibrational, and electrical transport properties of NbOCl2 under different hydrostatic environments were systematically investigated over a wide pressure range of 1.7–41.7 GPa using a diamond anvil cell coupled with in situ Raman spectroscopy, electrical conductivity, and high-resolution transmission electron microscopy (HRTEM) observations. Upon non-hydrostatic compression, NbOCl2 underwent a FE-to-antiferroelectric phase transition at 3.4 GPa, followed by a semiconductor-to-metal transformation at 15.7 GPa. Under hydrostatic compression, the FE transformation and metallization of NbOCl2 were postponed by ∼2.0 and ∼4.0 GPa due to the effect of helium pressure-transmitting medium. Upon decompression, the phase transition was demonstrated to be reversible under different hydrostatic environments, which was well corroborated by HRTEM analyses. In addition, the linear relations between electrical current and sinusoidal voltage with the nonlinearity factors of ∼1.0 reflect the Ohmic response of NbOCl2 before and after the FE transition. Our findings on NbOCl2 provide a guideline for exploring other layered FE materials under high pressure and establishing a design paradigm for new generations of FE-based devices.
Aerodynamics and surrounding flow patterns of a long-span bridge girder model with triple-separated boxes
Authors: Meng Hao , Chen Guanbin , Gao Donglai
Published: March 2024

The triple-box girder is finding broader applications in super long-span bridges for its excellent performance of flutter stability and traffic adaptability. In the present study, a bridge girder model with three separated boxes is experimentally investigated in detail via wind tunnel tests. In consideration of web modifications and accessory structures, the multi-point surface-pressure measurement and smoke-wire flow visualization are applied to investigate the aerostatic characteristics and flow structures. The “dual-frequency” phenomenon is found and explained for the bare girder with curved webs. For the present girder with linear webs, the global field is dominated by the separated-shear-layer instability. For the bare girder with curved webs, the upstream gap flow is dominated by the separated-shear-layer instability while the downstream gap flow is dominated by the double-shear-layer instability. The downstream gap flow exhibits obvious intermittent characteristics. In addition, non-Gaussian characteristic analysis of the surface wind pressures is introduced and improved for engineering practice. The distinguishing principle based on the skewness and kurtosis has high adaptability to both the bare girder and the completed bridge. In addition, semi-linear webs show better drag reduction. Combinations of accessory structures are also studied. The results show that during the construction process, prioritizing the installation of highway wind barriers can optimize the aerostatic performance of bridges. The present study embraces the booming era of long-span bridges with a triple-box girder and enriches the studies of bridge aerostatics.
Operation of a Ramsey-CPT microcell atomic clock with driving current-based power modulation of a VCSEL
Authors: Rivera-Aguilar C. M. , Callejo M. , Mursa A. , Carlé C. , Vicarini R. , Abdel Hafiz M. , Friedt J.-M. , Passilly N. , Boudot R.
Published: March 2024

We report on the operation of a coherent population trapping (CPT) microcell atomic clock using a pulsed Ramsey-like interrogation. The Ramsey-CPT sequence, defined by two-step optical pulses separated by a free-evolution dark time, is produced by switching on and off the output power of a low-power vertical-cavity surface-emitting laser, through direct modulation of its driving current. High-contrast and narrow Ramsey-CPT fringes are detected without the use of any external optical modulator stage. We demonstrate closed-loop operation of the clock based on high-speed digital signal processing implemented in a field programmable gate array board. The clock's short-term fractional frequency stability is 1.3 × 10−10τ−1/2 until 2000 s. A power light-shift coefficient of 8 × 10−11/μW, in relative value, is obtained for a dark time of 150 μs. This value is about ten times lower than in the continuous regime. These results show the feasibility of fully integrated atomic clocks based on Ramsey spectroscopy, which could provide enhanced long-term stability.
Influence of magnetic field on dynamic behavior of double-diffusive convection
Authors: Zhang Chao-Nan , Zheng Lai-Yun , Li Xu-Long , Qin Juan-Juan , Zhao Bing-Xin , Zhu Lin
Published: March 2024

Double-diffusive convection under an external magnetic field has several industrial applications, and how the magnetic field affects flow and heat and mass transfer is a research focus. This paper studies the dynamical behavior of two-dimensional double-diffusive convection in a uniform magnetic field is investigated using a high-accuracy numerical method. The effects of the magnetic field strength on the flow and on the heat and mass transfer are analyzed, and the process of flow transition in the presence of a magnetic field is studied. The results show that, as the strength of the magnetic field increases, the flow is gradually inhibited, and most of the heat transfer occurs through conduction. For a fixed magnetic field strength, the temperature-dominated flow changes from periodic to chaotic, and finally back to periodic, as the orientation of the magnetic field increases. Two types of periodic flow occur in the transition route, namely, a simple periodic flow with an integer multiple of the fundamental frequency and a complex periodic flow with multiple lower-frequency subharmonic waves. In the presence of a strong magnetic field, the effect of the magnetic field orientation on the flow is significant. At high Rayleigh numbers and a fixed magnetic field strength, the heat transfer efficiency of a vertical magnetic field surpasses that of a horizontal magnetic field by approximately 50% when temperature is dominant, achieving a mass transfer efficiency of about 100%. In cases when concentration is dominant, the heat transfer efficiency of a vertical magnetic field is 20% higher than that of a horizontal magnetic field, and the mass transfer efficiency is approximately 60% higher for the vertical magnetic field compared to the horizontal magnetic field. The flow transitions from chaotic or periodic to steady as the Prandtl number increases. The solution branch bifurcates at certain Prandtl numbers, and hysteresis appears when Prandtl number is equal to 0.023. For low Rayleigh numbers, the heat and mass transfer efficiencies increase monotonically with increasing Prandtl number under a weak magnetic field but remain constant for various Prandtl numbers under a strong magnetic field.
Translational eigenstates of He@C60 from four-dimensional ab initio potential energy surfaces interpolated using Gaussian process regression
Authors: Panchagnula K. , Graf D. , Albertani F. E. A. , Thom A. J. W.
Published: March 2024

We investigate the endofullerene system 3He@C60 with a four-dimensional potential energy surface (PES) to include the three He translational degrees of freedom and C60 cage radius. We compare second order Møller–Plesset perturbation theory (MP2), spin component scaled-MP2, scaled opposite spin-MP2, random phase approximation (RPA)@Perdew, Burke, and Ernzerhof (PBE), and corrected Hartree–Fock-RPA to calibrate and gain confidence in the choice of electronic structure method. Due to the high cost of these calculations, the PES is interpolated using Gaussian Process Regression (GPR), owing to its effectiveness with sparse training data. The PES is split into a two-dimensional radial surface, to which corrections are applied to achieve an overall four-dimensional surface. The nuclear Hamiltonian is diagonalized to generate the in-cage translational/vibrational eigenstates. The degeneracy of the three-dimensional harmonic oscillator energies with principal quantum number n is lifted due to the anharmonicity in the radial potential. The (2l + 1)-fold degeneracy of the angular momentum states is also weakly lifted, due to the angular dependence in the potential. We calculate the fundamental frequency to range between 96 and 110 cm−1 depending on the electronic structure method used. Error bars of the eigenstate energies were calculated from the GPR and are on the order of ∼±1.5 cm−1. Wavefunctions are also compared by considering their overlap and Hellinger distance to the one-dimensional empirical potential. As with the energies, the two ab initio methods MP2 and RPA@PBE show the best agreement. While MP2 has better agreement than RPA@PBE, due to its higher computational efficiency and comparable performance, we recommend RPA as an alternative electronic structure method of choice to MP2 for these systems.
Experimental investigation on visualization and quantitative characterization of filling and plugging performances of fractures in coal
Authors: Lou Zhen , Wang Kai , Zhao Wei , Wei Guoying , Yao Haowei , Qin Hengjie , Wei Xiaoge , Song Huaitao
Published: March 2024

Underground coalbed methane extraction is an important way for preventing coal mine gas disasters and reducing greenhouse gas emission, but air leakage around extraction boreholes is a critical factor that limits efficient coalbed methane extraction. Dynamically filling and plugging fractures around extraction boreholes can prevent air leakage. Due to the invisibility and complexity of underground geological formations, observing the process and effectiveness of plugging is extremely challenging. To visualize and quantitatively characterize the filling and plugging performances of fractures in coal. First, experiments are conducted to fill the coal damaged by the uniaxial and the triaxial loading-induced using a novel fracture filling experimental system under the constraint conditions. Then the multidimensional (point, surface, volume) plugging performances of fractures in coal before and after filling is visualized by the method of the X-ray computed tomography imaging. Finally, the quantitative characterization of filling and plugging performances of fractures in coal is conducted by testing changes in weight, fracture volume, and permeability before and after filling process. The experimental results show that after filling, the width and quantity of fractures in the coal significantly decreases, and the damaged coal is repaired. The filling ratio of fractures in coal fractured by uniaxial loading is 72%, and the fracture filling ratio in coal under triaxial loading is 68.1%. Under the influence of seepage and diffusion of plugging materials, the fractures are continuously filled, leading to a continuous decrease in the permeability of the fractured coal. The significant reduction in permeability of the fractured coal body is evident. The filling and plugging performances of fractures in coal is effective. The findings in this paper provide meaningful references and guidance for determining the filling and plugging parameters in underground gas extraction engineering practices.
Investigating the effect of drought stress and methanol spraying on the influential genes in the Calvin cycle and photorespiration of rapeseed (Brassica napus)
Authors: Taghvimi Parisa , Mohsenzadeh Golfazani Mohammad , Taghvaei Mohammad Mahdi , Samizadeh Lahiji Habibollah
Published: March 2024

Due to global warming and changes in precipitation patterns, many regions are prone to permanent drought. Rapeseed (Brassica napus) is one of the main sources of edible oils worldwide, and its production and yield are affected by drought. In this study, gene expression alterations under drought stress are investigated with bioinformatics studies to examine evolutionary relations of conserved motifs structure and interactions among Calvin cycle and photorespiration pathways key genes in drought-tolerant (SLM046) and drought-sensitive (Hayola308) genotypes of rapeseed. Investigating the conservation and evolutionary relationships revealed high conservation in motifs of FBPase, PRK, GlyK and NADP-ME enzymes. The analysis of protein interactions showed the correlation between FTRC, FBPase1, PRKX1, GlyKX2 and NADP-ME4 genes. Furthermore, in rapeseed, for the GlyKX2 and NADP-ME4 genes, four microRNAs of the miR172 family and four members of the miR167 family were identified as post-transcriptional regulators, respectively. The expression of ferredoxin thioredoxin reductase, fructose-1,6-bisphosphatase genes, phosphoribulokinase, glycerate kinase and malic enzyme 4 genes in the two rapeseed genotypes were evaluated by real-time qPCR method under 72 h of drought stress and methanol foliar application. As a result, the highest expression levels of FTRC, PRKX1, GlyKX2, NADP-ME4 and FBPase1 were observed in methanol foliar application on the SLM046 genotype at 24 h. In contrast, in methanol foliar application on the Hayola308 genotype, the highest expression levels of FTRC, PRKX1, GlyKX2, NADP-ME4 and FBPase1 were observed 8 h after the treatment. Our study illustrated that methanol foliar application enhanced plant tolerance under drought stress.
Impaired perception of cardiovascular risk and health literacy in individuals with high cardiovascular diseases risk from different socioeconomic levels in Antalya, Turkey
Authors: Ilgaz Ayşegül , Dağistan Akgöz Ayşe , Gözüm Sebahat
Published: March 2024

Background This study aimed to determine how the frequency of impaired perception of cardiovascular disease (CVD) risk is correlated with health literacy in individuals with high CVD risk in two regions with different socioeconomic levels. Methods A descriptive study was conducted. The Systematic Coronary Risk Estimation, recommended by the European and Turkish Cardiology Societies, provides recommendations based on individuals’ actual CVD risk levels. According to the Systematic Coronary Risk Estimation, participants suffering from diseases were identified as high and very high risk. The perception of risk was determined by subjectively assessing the risk level of the individuals. The European Health Literacy Survey Questionnaire was used. The Mann–Whitney U test, Chi-squared test and Spearman’s correlation analysis were used to analyse the data. We also conducted a logistic regression analysis to identify factors contributing to impaired perception of CVD risk. Results A total of 384 individuals, aged between 40 and 70 years (with a mean age of 58.35 ± 8.33 years), were included in the study. These individuals had a high risk of CVD and were registered to family health centres from two different socioeconomic levels. Out of the 384 participants, 201 individuals belonged to the lower socioeconomic level region and 183 individuals belonged to the higher socioeconomic level region. A total of 61.7% of the participants with high CVD risk had an impaired perception of CVD risk. The health literacy level of 59.9% of individuals was either inadequate or problematic. The health literacy score of participants with impaired risk perception (29.59 ± 9.07) was lower than those with correct risk perception (35.83 ± 10.94; P < 0.001). Factors that affected the perception of CVD risk included age, education level, working status, occupation, a family history of CVD, the CVD risk assessment by health professionals and the recommendation of health professionals to individuals for CVD screening. Conclusions It is necessary for health care professionals to make risk assessments and perform interventions to improve health literacy to raise the awareness of individuals with high CVD risk on their actual risk.
Automotive braking is a source of highly charged aerosol particles
Authors: Thomas Adam E. , Bauer Paulus S. , Dam Michelia , Perraud Véronique , Wingen Lisa M. , Smith James N.
Published: March 2024

Although the last several decades have seen a dramatic reduction in emissions from vehicular exhaust, nonexhaust emissions (e.g., brake and tire wear) represent an increasingly significant class of traffic-related particulate pollution. Aerosol particles emitted from the wear of automotive brake pads contribute roughly half of the particle mass attributed to nonexhaust sources, while their relative contribution to urban air pollution overall will almost certainly grow coinciding with vehicle fleet electrification and the transition to alternative fuels. To better understand the implications of this growing prominence, a more thorough understanding of the physicochemical properties of brake wear particles (BWPs) is needed. Here, we investigate the electrical properties of BWPs as emitted from ceramic and semi-metallic brake pads. We show that up to 80% of BWPs emitted are electrically charged and that this fraction is strongly dependent on the specific brake pad material used. A dependence of the number of charges per particle on charge polarity and particle size is also demonstrated. We find that brake wear produces both positive and negative charged particles that can hold in excess of 30 elementary charges and show evidence that more negative charges are produced than positive. Our results will provide insights into the currently limited understanding of BWPs and their charging mechanisms, which potentially have significant implications on their atmospheric lifetimes and thus their relevance to climate and air quality. In addition, our study will inform future efforts to remove BWP emissions before entering the atmosphere by taking advantage of their electric charge.
Structure of RADX and mechanism for regulation of RAD51 nucleofilaments
Authors: Balakrishnan Swati , Adolph Madison , Tsai Miaw-Sheue , Akizuki Tae , Gallagher Kaitlyn , Cortez David , Chazin Walter J.
Published: March 2024

Replication fork reversal is a fundamental process required for resolution of encounters with DNA damage. A key step in the stabilization and eventual resolution of reversed forks is formation of RAD51 nucleoprotein filaments on exposed single strand DNA (ssDNA). To avoid genome instability, RAD51 filaments are tightly controlled by a variety of positive and negative regulators. RADX (RPA-related RAD51-antagonist on the X chromosome) is a recently discovered negative regulator that binds tightly to ssDNA, directly interacts with RAD51, and regulates replication fork reversal and stabilization in a context-dependent manner. Here, we present a structure-based investigation of RADX’s mechanism of action. Mass photometry experiments showed that RADX forms multiple oligomeric states in a concentration-dependent manner, with a predominance of trimers in the presence of ssDNA. The structure of RADX, which has no structurally characterized orthologs, was determined ab initio by cryo-electron microscopy (cryo-EM) from maps in the 2 to 4 Å range. The structure reveals the molecular basis for RADX oligomerization and the coupled multi-valent binding of ssDNA binding. The interaction of RADX with RAD51 filaments was imaged by negative stain EM, which showed a RADX oligomer at the end of filaments. Based on these results, we propose a model in which RADX functions by capping and restricting the end of RAD51 filaments.
The Angiosperm Terrestrial Revolution buffered ants against extinction
Authors: Jouault Corentin , Condamine Fabien L. , Legendre Frédéric , Perrichot Vincent
Published: March 2024

With ~14,000 extant species, ants are ubiquitous and of tremendous ecological importance. They have undergone remarkable diversification throughout their evolutionary history. However, the drivers of their diversity dynamics are not well quantified or understood. Previous phylogenetic analyses have suggested patterns of diversity dynamics associated with the Angiosperm Terrestrial Revolution (ATR), but these studies have overlooked valuable information from the fossil record. To address this gap, we conducted a comprehensive analysis using a large dataset that includes both the ant fossil record (~24,000 individual occurrences) and neontological data (~14,000 occurrences), and tested four hypotheses proposed for ant diversification: co-diversification, competitive extinction, hyper-specialization, and buffered extinction. Taking into account biases in the fossil record, we found three distinct diversification periods (the latest Cretaceous, Eocene, and Oligo-Miocene) and one extinction period (Late Cretaceous). The competitive extinction hypothesis between stem and crown ants is not supported. Instead, we found support for the co-diversification, buffered extinction, and hyper-specialization hypotheses. The environmental changes of the ATR, mediated by the angiosperm radiation, likely played a critical role in buffering ants against extinction and favoring their diversification by providing new ecological niches, such as forest litter and arboreal nesting sites, and additional resources. We also hypothesize that the decline and extinction of stem ants during the Late Cretaceous was due to their hyper-specialized morphology, which limited their ability to expand their dietary niche in changing environments. This study highlights the importance of a holistic approach when studying the interplay between past environments and the evolutionary trajectories of organisms.
Apport de la littératie informationnelle et multimodale dans la pratique traductive
Authors: Jeanmaire Guillaume , Kim Daeyoung
Published: March 2024

La profusion des sources à disposition des traducteurs (outils d’aide à la traduction: corpus monolingues ou
parallèles en ligne, bases terminologiques, mémoires de traduction, etc.) et à la rédaction démultiplie et complexifie le
processus de traduction. Ainsi, pour une meilleure gestion de ressources de plus en plus hétérogènes, et des procédures liées à
leur exploitation, nous montrons comment nos cours de traduction ont profité de la rédaction méthodique de journaux de
progression, présentés en classe à l’oral (mutualisés et commentés en ligne, par l’enseignant et les autres élèves), consignant
leurs pratiques réflexives sur leur cheminement méthodique, d’abord individuels, puis co-construits, mutualisés et commentés sur
une plateforme collaborative. La littératie informationnelle mais aussi multimodale (croquis explicatifs, adaptation
cinématographique d’une œuvre littéraire, recherche par images) se révèle essentielle tant en traduction audiovisuelle que
littéraire, en particulier pour traduire l’intertextualité, l’interculturel et l’implicite.
Bangladeshi EAP teachers’ perspectives on task-based language
teaching
Authors: Siddiqui Tamoha , Winke Paula
Published: March 2024

We explored the extent to which academic English teachers from
an English-as-a-Foreign-Language (EFL) context held beliefs that aligned with
Task-Based Language Teaching (TBLT) principles, as well as their levels of
receptiveness to using tasks in the classroom. In this mixed methods study, 41
tertiary-level EFL teachers from Bangladesh were invited to take a survey on TBLT and
participate in follow-up interviews. We used convergent mixed methods analysis
to triangulate the data and verify the findings. Results showed that
participants agreed with TBLT principles from a moderate to high level, and
consistently favored use of tasks over traditional activities, which included
audio-lingual and form-based instruction. Moreover, teacher beliefs and
practices seemed to have become further aligned with TBLT tenets in light of the
COVID-19 pandemic and its consequential shift to online teaching.
Chinese EFL teachers’ understandings and implementation of task-based language teaching
Authors: Li Hongyu , Thomas Nathan
Published: March 2024

Across China, English language teaching curricula have advocated for task-based language teaching (TBLT) for more
than 20 years. Yet, there is reason to believe that practice varies widely. As such, this multiple case study sheds light on two
Chinese teachers’ understandings and implementation of TBLT in a public primary school in Chongqing, southwest China. Data
collection consisted of eight semi-structured interviews and eight classroom observations. Data were analyzed using qualitative
content analysis. The analysis indicated that the teachers had basic understandings of TBLT, but their teaching was incongruent
with its principles. Few tasks were observed in their lessons. Three main factors affected the teachers’ implementation of TBLT:
(1) classroom management issues; (2) preparation and teaching resources; and (3) the teachers’ own tacit reluctance.
Unimodular Plebański gravity
Authors: Gielen Steffen , Nash Elliot
Published: March 2024

We present new action principles for unimodular gravity, defined in the chiral Plebański formulation based on (complex) two-forms and a complex

SO
(
3
)

connection. In these theories, just as in their analogues in the metric formulation, the cosmological constant does not take a prescribed value but is an integration constant whose value can differ between different (classical) solutions. We discuss some subtleties when identifying Lorentzian solutions in the generally complex theory, and show how these theories can be reduced to a ‘pure connection’ form similar to Krasnov’s pure connection formalism for general relativity.
Solutions with pure radiation and gyratons in 3D massive gravity theories
Authors: Kilicarslan Ercan , Kolář Ivan
Published: March 2024

We find exact solutions of topologically massive gravity (TMG) and new massive gravity (NMG) in 2 + 1 dimensions (3D) with an arbitrary cosmological constant, pure radiation, and gyratons, i.e. with possibly non-zero T

uu
and T

ux
in canonical coordinates. Since any ‘reasonable’ geometry in 3D (i.e. admitting a null geodesic congruence) is either expanding Robinson–Trautman (

Θ
≠
0

) or Kundt (

Θ
=
0

), we focus on these two classes. Assuming expansions

Θ
=
1

/

r

(‘GR-like’ Robinson–Trautman) or

Θ
=
0

(general Kundt), we systematically integrate the field equations of TMG and NMG and identify new classes of exact solutions. The case of NMG contains an additional assumption of g

ux
being quadratic in r, which is automatically enforced in TMG as well as in 3D GR. In each case, we reduce the field equations as much as possible and identify new classes of solutions. We also discuss various special subclasses and study some explicit solutions.
Advancements in tunable and multifunctional metamaterial absorbers: a comprehensive review of microwave to terahertz frequency range
Authors: Liu Yunpeng , Dong Lin , Sabri Mohd Faizul Mohd , Majid Nazia Abdul , Ibrahim Suriani
Published: March 2024

Over the past two decades, metamaterial absorbers have undergone significant advancements, evolving from microwave single-frequency designs to multi-frequency and broadband absorption, extending into the terahertz band. These absorbers have transitioned from unadjustable to adjustable and multifunctional configurations, enabled by the integration of adjustable materials, mechanical structures, and semiconductor devices. This article provides a comprehensive review of the progress achieved in the microwave to terahertz frequency range over the last five years. Key aspects covered include the absorbing mechanism of metamaterials in the microwave frequency band, with absorption efficiencies exceeding 90% for specific frequency ranges. The development of adjustable absorbers allows for frequency tunability within ±10% of the central frequency, while multifunctional absorbers enable concurrent control over absorption and reflection properties. In the terahertz regime, advanced electromagnetic simulations have led to absorber designs with bandwidths exceeding 50% of the central frequency, resulting in absorption efficiencies above 80% over the entire bandwidth. Integration of gallium nitride-based gallium nitride high electron mobility transistors provides fast switching speeds below 100 ns, facilitating rapid reconfiguration of absorber functionalities. These advancements in metamaterial absorbers offer promising prospects for intelligent and integrated designs in future applications.
Simultaneous improvement of high-frequency and Baliga figures of merit of 1.7 kV 4H-SiC MOSFET with retrograded JFET doping
Authors: Wang Qian , Hua Hao , Zheng Li , Feng Junhong , Zhang Cheng , Gao Mingyang , Qiu Kun , Luo Jian , Cheng Xinhong
Published: March 2024

The 1.7 kV 4H-SiC MOSFET which features optimized retrograded-profile ion implantation in the JFET regions (RG-MOS) is proposed and fabricated on the 4 inch wafers. The measured results quantify the benefits of the RG-MOS structure: simultaneous improvement in high-frequency figures of merit (HF-FOM) (R
on× C
GD) by 1.5×, HF-FOM (R
on × Q
GD) by 1.5× and Baliga figure of merit (BFOM = 4BV2/R
on,sp) by 1.6× compared with the conventional MOSFET (CON-MOS). Unlike other reported complicated structures which need high-precise fabricating process, the proposed RG-MOS structure is compatible with the prior planar 4H-SiC MOSFET process, and is favorable for large-scale production.
Absorption loss properties and Stokes shifts of InGaAs-based self-assembled well-wire-hybrid quantum structures
Authors: Duan Ruonan , Wang Yuhong , Tai Hanxu , Shi Yue , Zheng Ming , Zhang Jianwei , Zhang Xing , Ning Yongqiang , Wu Jian
Published: March 2024

Stokes shift is an important physical property relating to emission and absorption of light-emitting diodes, which reflects photon self-absorption situation and affects the device performance. Nowadays, it is becoming more and more difficult to change Stokes shift and relevant physical properties to further improve device performance with traditional quantum structures from increasing requirements in application. Therefore, hybrid quantum structures have attracted an attention recently. However, the properties related to Stokes shift in the new configurations have not been revealed so far. In this paper, we investigate the absorption loss and Stokes shift of the newly proposed InGaAs self-assembled well-wire-hybrid quantum structure. By designing a new absorption loss measurement approach, we can conveniently extract internal optical mode loss of a quantum structure and explore its Stokes shift with the measured absorption spectra. Our findings reveal that the presence of quantum wires in the structure can significantly reduce the Stokes shift difference between transverse electric and transverse magnetic (TM) polarizations from 66.7% for a traditional quantum well to 15.4%. It suggests the potential for the reduction of TM-mode photon self-absorption in a compressive-strain quantum structure. This phenomenon offers new prospects for the development of polarization-insensitive devices.
Investigation on the phase transition, geometric and electronic properties of Bi-doped CsPbBr3 perovskites
Authors: Luo Xiang , Song Yixian , Zhao Yiting , Lu Ying-Bo , Cong Wei-Yan , Wu Zhong-Chen
Published: March 2024

Given the ongoing debate regarding the potential impact of Bi dopant on the phase transition of CsPbBr3, our study aims to provide a comprehensive understanding of this phenomenon. Through a multifaceted examination encompassing energetic states, geometric configurations, bonding interactions, and electronic structures, we find that the inclusion of Bi dopants alone does not directly induce the orthorhombic/tetragonal phase transition in CsPbBr3. However, we observe a obvious reduction in the energetic discrepancy between these two phases, indicating an indirect stimulation of the phase transition by Bi dopants. This accelerates the stimulations originating from external environment, which may be responsible for the experimentally observed phase transition. Moreover, our investigation confirms that Bi dopants selectively weakens the bonding interaction within the Pb/Bi octahedra of the CsPbBr3 lattice in an anisotropic manner. Specifically, we identify that the weakening of the out-of-plane Bi–Br bond strength arises from the diminished bonding interaction between the p orbital of Bi and the s orbital of Br. This phenomenon results in the elongation of the metal-halide octahedra, consequently relaxing lattice distortions and twists in undoped CsPbBr3 systems, particularly pronounced in orthorhombic phases. Consequently, both orthorhombic and tetragonal CsPbBr3 lattices tend to evolve towards similar geometric configurations. Our findings reveal the significant influence of Bi dopants on the phase dynamics of CsPbBr3, a factor often overlooked in previous investigations.
Frontiers in all electrical control of magnetization by spin orbit torque
Authors: Hu Shuai , Qiu Xuepeng , Pan Chang , Zhu Wei , Guo Yandong , Shao Ding-Fu , Yang Yumeng , Zhang Delin , Jiang Yong
Published: March 2024

Achieving all electrical control of magnetism without assistance of an external magnetic field has been highly pursued for spintronic applications. In recent years, the manipulation of magnetic states through spin–orbit torque (SOT) has emerged as a promising avenue for realizing energy-efficient spintronic memory and logic devices. Here, we provide a review of the rapidly evolving research frontiers in all electrical control of magnetization by SOT. The first part introduces the SOT mechanisms and SOT devices with different configurations. In the second part, the developments in all electrical SOT control of magnetization enabled by spin current engineering are introduced, which include the approaches of lateral symmetry breaking, crystalline structure engineering of spin source material, antiferromagnetic order and interface-generated spin current. The third part introduces all electrical SOT switching enabled by magnetization engineering of the ferromagnet, such as the interface/interlayer exchange coupling and tuning of anisotropy or magnetization. At last, we provide a summary and future perspectives for all electrical control of magnetization by SOT.
An interpretation for the components of 2p
3/2 core level x-ray photoelectron spectra of the cations in some inverse spinel oxides
Authors: Subedi Arjun , Yang Detian , Chin Wai Kiat , Tamang Binny , Sahoo Sushrisangita , Yancey Paul , Mahbub Rifat , Shield Jeffrey , Lai Rebecca Y , Xu Xiaoshan , Dowben Peter A , Rangari Vijaya
Published: March 2024

In an effort to reconcile the various interpretations for the cation components of the 2p
3/2 observed in x-ray photoelectron spectroscopy (XPS) of several spinel oxide materials, the XPS spectra of both spinel alloy nanoparticles and crystalline thin films are compared. We observed that different components of the 2p
3/2 core level XPS spectra, of these inverse spinel thin films, are distinctly surface and bulk weighted, indicating surface-to-bulk core level shifts in the binding energies. Surface-to-bulk core level shifts in binding energies of Ni and Fe 2p
3/2 core levels of NiFe2O4 thin film are observed in angle-resolved XPS. The ratio between surface-weighted components and bulk-weighted components of the Ni and Fe core levels shows appreciable dependency on photoemission angle, with respect to surface normal. XPS showed that the ferrite nanoparticles Ni
x
Co1−x
Fe2O4 (x = 0.2, 0.5, 0.8, 1) resemble the surface of the NiFe2O4 thin film. Surface-to-bulk core level shifts are also observed in CoFe2O4 and NiCo2O4 thin films but not as significantly as in NiFe2O4 thin film. Estimates of surface stoichiometry of some spinel oxide nanoparticles and thin films suggested that the apportionment between cationic species present could be farther from expectations for thin films as compared to what is seen with nanoparticles.
Robust transfer subspace learning based on low-rank and sparse representation for bearing fault diagnosis
Authors: Yu Fuchao , Xiu Xianchao , Li Xinrong , Liu Jingjing
Published: March 2024

With the development of industrial intelligence, data-driven fault diagnosis plays an important role in prognostics and health management. However, there is usually a large amount of unlabeled data from different working conditions, making cross-domain fault diagnosis unstable and inflexible. To deal with this issue, we propose two novel transfer subspace learning methods based on the low-rank sparse representation (LRSR), called LRSR-G and LRSR-R. Specifically, LRSR-G integrates an additional matrix with LRSR to characterize the Gaussian noise for robustness, as well as capture global and local structures. Furthermore, LRSR-R adaptively learns the label matrix from samples instead of using the binary labeling matrix in LRSR-G, thus providing the possibility to improve the flexibility. In addition, we develop two efficient algorithms using the alternating direction method of multipliers to solve the proposed LRSR-G and LRSR-R. Extensive experiments are conducted on the Case Western Reserve University dataset and Jiangnan University (JNU) dataset. The results show that the proposed LRSR-G and LRSR-R perform better than the existing methods, while LRSR-R has more potential in cross-domain fault diagnosis tasks.
Multicomponent collaborative time-frequency state-space model for vibration signal decomposition under nonstationary conditions
Authors: Huang Xin , Chen Wenwu , Qu Dingrong , Liu Xiaojin , Shao Huajin
Published: March 2024

The implementation of prognostics and health management strategies is essential for enhancing the safety and maintenance of rotating equipment in chemical plants. The examination of vibration signal behaviours under variable-speed conditions and the development of signal decomposition methods in such contexts are of substantial theoretical and practical relevance. This paper proposes a novel multicomponent collaborative time-frequency state-space method for the decomposition of vibration signals. The method employs a multi-component proportional model to accurately describe the synchronisation of high-frequency components with the rotational frequency component. Based on this framework, the instantaneous frequency change curves of multiple components are input into the Vold–Kalman filter algorithm for precise decomposition of multicomponent vibration signals under variable-speed conditions. Experimental results demonstrate the effectiveness of the proposed method in achieving accurate instantaneous frequency tracking and signal decomposition, showing clear advantages over traditional methods.
Research progress of out-of-plane GeSn nanowires
Authors: Shen Ya , Chen Wanghua , Sun Bai
Published: March 2024

With the increasing integration density of silicon-based circuits, traditional electrical interconnections have shown their technological limitations. In recent years, GeSn materials have attracted great interest due to their potential direct bandgap transition and compatibility with silicon-based technologies. GeSn materials, including GeSn films, GeSn alloys, and GeSn nanowires, are adjustable, scalable, and compatible with silicon. GeSn nanowires, as one-dimensional (1D) nanomaterials, including out-of-plane GeSn nanowires and in-plane GeSn nanowires, have different properties from those of bulk materials due to their distinctive structures. However, the synthesis and potential applications of out of plane GeSn nanowires are rarely compared to highlighting their current development status and research trends in relevant review papers. In this article, we present the preparation of out-of-plane GeSn nanowires using top-down (etching and lithography) and bottom-up (vapor–liquid–solid) growth mechanism in the vapor-phase method and supercritical fluid–liquid–solid, solution-liquid–solid, and solvent vapor growth mechanisms in the liquid-phase method) methods. Specifically, the research progress on typical out of plane GeSn nanowires are discussed, while some current development bottlenecks are also been identified. Finally, it is also provided a brief description of the applications of out-of-plane GeSn nanowires with various Sn contents and morphologies.