bluuebunny/crossref_metadata_2025 huggingface dataset:
Peristaltic flow of bioconvective Ree–Eyring nanofluid through an inclined elastic channel with partial slip effects
Authors: Ajithkumar M. , Lakshminarayana P. , Vajravelu K.
Published: October 2023

Pharmaceutical fluid processing is a procedure of medication manufacturing, utilizing a particular kind of heat transfer in a biofluid designed to maintain the desired temperature for extended periods. Choosing a suitable fluid can have a positive effect on the operating efficacy of the system and lengthen the fluid’s and system’s life spans. As an outcome of this development, we investigate the influence of the partial slip and gyrotactic microorganisms on the peristaltic transport of a magnetohydrodynamic Ree–Eyring nanofluid via an aligned porous conduit with thermal radiation, energy generation, along with cross and double diffusion effects. By invoking suitable nondimensional parameters, the proposed dimensional governing equations are transformed into a system of dimensionless partial differential equations. The analytical solutions for the system of partial differential equations are obtained by incorporating the homotopy perturbation method. Further, tabular and graphical presentations are used to examine the characteristics of the various sundry parameters on the temperature, concentration, motile microorganism density, axial velocity, trapping, and other relevant flow quantities. The observations of this study indicate that the Darcy number and thermal Grashof number have the capability to enhance the velocity distribution of the Ree–Eyring nanofluid in the presence of bioconvection. The trapped bolus size and the skin friction coefficient increase noticeably because of an enhancement in the Ree–Eyring fluid parameter. Also, the Darcy number and the Hall current parameter increase the skin friction coefficient. Furthermore, validation of the results is carried out to examine the consistency between the current and the previous findings for some special cases and excellent agreements are found.
Electronically preresonant stimulated Raman scattering microscopy in the visible
Authors: Choorakuttil A. J. X. , Pruccoli A. , Winterhalder M. J. , Zirak P. , Gudavičius D. , Martynaitis G. , Petrulionis D. , Samsonas D. , Kontenis L. , Zumbusch A.
Published: October 2023

We report an experimental scheme for stimulated Raman scattering (SRS) microscopy with excitation in the visible spectral region. This allows electronically preresonant (epr) SRS microscopy of a broad range of chromophores with sensitivities as low as 1 μM. Our experiment is based on two synchronously near-infrared pumped optical parametric oscillators (OPO). One of the outputs is modulated at a fourth of the repetition rate with a novel broadband electro-optical modulator. Using a combination of spectral focusing and tuning of the OPO, we show the recording of epr-SRS spectra over the whole range of molecular vibrations at a speed up to 20 times faster than classical wavelength tuning. The imaging capabilities of this setup are demonstrated with material scientific and cellular samples.
First-principles study on the enhancement of structure stability and magnetocrystalline anisotropy energy of L10-ordered Mn1−xFexAlC compound for permanent magnet application
Authors: Vero Khoveto , Islam Riyajul , Borah J. P.
Published: October 2023

L10-MnAl exhibits excellent magnetic properties and could be used as a candidate to fill the gap between hard ferrite and rare-earth based permanent magnet (PM) applications. However, one of the major problems with L10-MnAl is that the structure is metastable and decomposes to other structural phases at higher temperature. Therefore, enhancing the structure stability of L10-MnAl is essential for PM applications. We studied the prospect of improving the structural stability and increasing the uniaxial magnetic anisotropy energy (Ku) of the L10-MnAl structure in this work. It is found that C-doping at the 1d interstitial site enhanced the structure stability of the compound. Moreover, Fe substitution on Mn sites shows a significant increase in the uniaxial magnetic anisotropy energy (Ku). Therefore, the electronic structure and magnetic properties of L10-ordered Mn1−xFexAlC (x = 0, 0.125, 0.250, 0.375, 0.50, 0.625, 0.75, and 0.87) alloys are investigated by using the first-principles calculations. The results show that x = 0.375 Fe content in the L10-MnAl alloy and 6% doping of C maintained the structural stability and provided a maximum value of Ku = 2.13 (MJ/m3), which is 25% higher than for the pristine L10-MnAl, making it suitable for permanent magnet applications.
Multiple exceptional points and phase transitions of a one-dimensional PT-symmetric Lieb photonic lattice
Authors: Zhang Yingying , Xia Shiqiang , Qin Lu , Wang Qi , Jia Pengbo , Qi Wenrong , Feng Xuejing , Jiang Yajing , Zhu Zunlue , Zhao Xingdong , Liu Wuming , Liu Yufang
Published: October 2023

Exceptional points (EPs) in non-Hermitian systems have attracted enormous attention and spawned intriguing prospects for the manipulation of waves. Despite many efforts focusing on the exotic behaviors about EPs, there are only a few studies of phase transitions involving multiple EPs. Here, by employing staggered couplings as well as two pairs of on-site gain/loss, we propose a one-dimensional parity-time (PT)-symmetric Lieb photonic lattice and demonstrate diverse phase transitions of such a multiband structure. Owing to the non-Hermitian chiral symmetry, symmetry-protected higher-order EPs are constructed, and the system exhibits PT symmetry breaking beyond a certain threshold. More importantly, both the relative couplings and the on-site gain/loss can be flexibly reconfigured on demand, which yields the degeneracy of different bands, i.e., the emergence of multiple EPs. We also unveil that the EPs will no longer exist in the presence of a non-Hermitian diagonal disorder. In contrast, the spectrum remains symmetric and the EPs, along with the flatband, are robust against the off diagonal disorder due to the preserved non-Hermitian particle-hole symmetry. Our work not only provides a controllable platform for studying EPs but also sheds light on the exciting non-Hermitian physics based on exceptional degeneracies.
Frequency tunable coherent perfect absorption and lasing in radio-frequency system for ultrahigh-sensitive sensing
Authors: Wu Jianhui , Li Jie , Zhang Chi , Liu Yulu , Xu Liangquan , Xuan Weipeng , Jin Hao , Dong Shurong , Luo Jikui
Published: October 2023

A coherent perfect absorption-lasing (CPAL) point in non-Hermitian physics systems has infinite output amplitudes (or quality factor) theoretically and has been utilized for applications. However, practical implementation of CPAL systems faces extreme challenges because of the deviations of electronic components from ideal values, which makes it difficult to attain the CPAL state. Moreover, the amplitude-based output is easily interfered by noises or environments and is inferior as compared to frequency shift-based sensing. Through the investigation of the effects of component deviations on general CPAL systems, we propose an eigenstate tuning method specifically tailored for radio-frequency (RF) CPAL systems. The method enables the realization of CPAL states at any desired frequency with dynamic ranges of signal amplitudes exceeding 60 dB experimentally or to work at a frequency shift-based sensing. Then, a CPAL-based RF sensor system is developed for verification, showing an ultrahigh sensitivity of 1.9 dB/10 fF by measuring output coefficient variation or 9.4 MHz/pF by measuring frequency shift, significantly broadening the application scope of CPAL systems.
A nonlinear dynamic hysteresis model with magnetic-thermal-stress-fluid coupling effect for hydraulically amplified magnetostrictive actuator
Authors: Li Yuesong
Published: October 2023

The hydraulic amplified magnetostrictive actuator (HAMA) has the advantages of large output displacement and fast response speed, but it is affected by coupling effects of electromagnetism, temperature, prestress, fluid, and other factors. In order to accurately analyze its performance, it is necessary to establish a nonlinear dynamic model including the coupling effect of eddy current loss, hysteresis, prestress, temperature, and fluid. First, a nonlinear magnetostrictive model including the magnetic-thermal-stress coupling effect is developed from the perspective of free energy. Based on the conservation of magnetization energy, the influence term of the eddy current is added to the anhysteretic magnetization and a nonlinear dynamic magnetization model including the effect of eddy current is developed. Based on the fluid transmission theory and HAMA’s equivalent dynamic model, a dynamic model of HAMA was established. Finally, a nonlinear dynamic hysteresis model with the magneto-thermal-stress-fluid coupling effect of HAMA is developed, and the performance of HAMA was studied by simulation and experiments. The results show that the output displacement is from −58.2 to 58.2 µm when the control current changes from −2 to 2 A, and the simulation results have a better agreement with the experiment result when the frequency is less than 200 Hz.
Secrets of the Saltmarsh
Authors: Saxby Claire , Rogerson Alicia
Published: October 2023

You will find me where land meets sea …

Saltmarshes are full of energy and life. They provide food and shelter for migratory birds as well as microscopic plants and animals. They also protect our coastlines. Most of all, saltmarshes are places of discovery and wonder.

With lyrical text and captivating illustrations, Secrets of the Saltmarsh offers a close-up look at the fascinating world of saltmarsh wetlands.

Reading level varies from child to child, but we recommend this book for ages 5–9.
A high-resolution large-eddy simulation framework for wildland fire predictions using TensorFlow
Authors: Wang Qing , Ihme Matthias , Linn Rod R. , Chen Yi-Fan , Yang Vivian , Sha Fei , Clements Craig , McDanold Jenna S. , Anderson John
Published: October 2023

Background Wildfires are becoming more severe, so we need improved tools to predict them over a wide range of conditions and scales. One approach towards this goal entails the use of coupled fire/atmosphere modelling tools. Although significant progress has been made in advancing their physical fidelity, existing tools have not taken full advantage of emerging programming paradigms and computing architectures to enable high-resolution wildfire simulations. Aims The aim of this study was to present a new framework that enables landscape-scale wildfire simulations with physical representation of combustion at an affordable cost. Methods We developed a coupled fire/atmosphere simulation framework using TensorFlow, which enables efficient and scalable computations on Tensor Processing Units. Key results Simulation results for a prescribed fire were compared with experimental data. Predicted fire behavior and statistical analysis for fire spread rate, scar area, and intermittency showed overall reasonable agreement. Scalability analysis was performed, showing close to linear scaling. Conclusions While mesh refinement was shown to have less impact on global quantities, such as fire scar area and spread rate, it benefits predictions of intermittent fire behavior, buoyancy-driven dynamics, and small-scale turbulent motion. Implications This new simulation framework is efficient in capturing both global quantities and unsteady dynamics of wildfires at high spatial resolutions.
Does your regional variety help you acquire an additional language?
Authors: Perpiñán Sílvia , Montrul Silvina
Published: October 2023

This study investigates Differential Object Marking (DOM) in Italian speakers from two dialectal areas–North and
South Italy–learning Spanish. Southern Italo-Romance varieties exhibit a DOM system through a-marking, like
Spanish, whereas the Northern varieties, like Standard Italian, only allow DOM with pronouns. Given the structural differences and
similarities among these typologically close languages, we ask whether a stigmatized oral regional variety has the potential to
transfer in the acquisition of additional languages. Participants (n = 103) completed an acceptability judgment
task (AJT) and an oral production task testing DOM in [±animate, ±definite] DP contexts. The results revealed differences
modulated by proficiency in the written AJT that moderately favored the Northern learners and in the oral production task that
favored the Southern learners. These findings suggest that low-prestige varieties may not have the full potential to transfer at
early stages of acquisition due to their inhibition in formal contexts, but that they can emerge in less formal tasks. We argue
that current theoretical models that prioritize linguistic proximity as the primary source of transfer at initial stages of L3 acquisition are
unable to capture revealing patterns from understudied sociolinguistic contexts that bring new light to the study of
multilingualism.
Tunable Memory and Activity of Quincke Particles in Micellar Fluid
Authors: Yang 杨 Yang 洋 , Fei Zhang 张 Meng 梦菲 , Zhu 朱 Lailai 来来 , Hui Zhang 张 Tian 天辉
Published: October 2023

Memory can remarkably modify the collective behavior of active particles. We show that, in a micellar fluid, Quincke particles driven by a square-wave electric field exhibit a frequency-dependent memory. Upon increasing the frequency, a memory of directions emerges, whereas the activity of particles decreases. As the activity is dominated by interaction, Quincke particles aggregate and form dense clusters, in which the memory of the direction is further enhanced due to the stronger electric interactions. The density-dependent memory and activity result in dynamic heterogeneity in flocking and offer a new opportunity for research of collective motions.
Observation of Enhanced Faraday Effect in Eu-Doped Ce:YIG Thin Films
Authors: Zhang 张 Han-Xu 晗旭 , Zhu 朱 Sen-Yin 森寅 , Zhan 湛 Jin 劲 , Wang 王 Xian-Jie 先杰 , Wang 王 Yi 一 , Yao 姚 Tai 泰 , Mezin N. I. , Song 宋 Bo 波
Published: October 2023

Ce:YIG thin films are taken as an ideal candidate for magneto-optical devices with giant Faraday effect in the near-infrared range, but it is hindered by a limited Ce3+/Ce4+ ratio and a high saturation driving field. To address this issue, Eu doping can increase the Faraday rotation angle by ∼ 40% to 1.315 × 104 deg/cm and decrease the saturation driving field by ∼ 38% to 1.17 kOe in Eu0.75Ce1Y1.25Fe5O12 compared to Ce1Y2Fe5O12 pristine. The mechanism is attributed to the conversion of Ce4+ to Ce3+ and the weakening of ferrimagnetism by Eu doping. This work not only provides strategies for improving Ce3+/Ce4+ ratio in Ce:YIG, but also develops (Eu,Ce):YIG with a promising Faraday rotation angle for magneto-optical devices.
Galaxy rotation curve in hyperconical universes: a natural relativistic MOND
Authors: Monjo Robert
Published: October 2023

Modified Newtonian dynamics (MOND) and similar proposals can (at least partially) explain the excess rotation of galaxies or the equivalent mass-discrepancy acceleration, without (or by reducing) the requirement of dark matter halos. This paper develops a modified gravity model to obtain local limit to the general relativity (GR) compatible with a cosmological metric different to the standard Friedmann–Lemaître–Robertson–Walker metric. Specifically, the paper uses a distorted stereographic projection of hyperconical universes, which are 4D hypersurfaces embedded into 5D Minkowski spacetime. This embedding is a key in the MOND effects found in galactic scales. To adequately describe the mass-discrepancy acceleration relation, centrifugal force would present a small time-like contribution at large-scale dynamics due to curvature of the Universe. Therefore, the Lagrangian density is very similar to the GR but with subtracting the background curvature (or vacuum energy density) of the perturbed hyperconical metric. Results showed that the proposed model adjusts well to 123 galaxy rotation curves obtained from the Spitzer Photometry and Accurate Rotation Curves database, using only a free parameter.
The effects of gravitational waves on a hydrogen atom
Authors: Wanwieng N , Chattrapiban N , Watcharangkool A
Published: October 2023

We investigate the influence of gravitational waves on a freely falling hydrogen atom by analyzing the dynamics of the bound electron described by the Dirac equation in the curved spacetime of a gravitational wave. From this, we derive the corresponding Dirac Hamiltonian in the local inertial frame of the atom, assuming gravitational waves are described by the linearized theory of general relativity. To maintain meaningful physical interpretations while obtaining a non-relativistic description, we employ the Foldy–Wouthuysen transformation. Through the analysis of resulting interaction terms and comparison with flat spacetime counterparts, valuable insights into the effects of gravitational waves (GWs) on the hydrogen atom are gained. Additionally, we explore selection rules governing the coupling between GWs and the atom and utilize first-order perturbation theory to quantify the induced energy shifts and spectral line splitting. This investigation contributes to our understanding of the interplay between quantum systems and gravitational waves, which could lead to alternative method of GWs indirect detection. However, measuring such tiny energy shifts would require a telescope with very high spectral resolution.
Phase recovery from phaseless scattering data for discrete Schrödinger operators
Authors: Novikov Roman , Sharma Basant Lal
Published: October 2023

We consider scattering for the discrete Schrödinger operator on the square lattice

Z

d

,

d
⩾
1

, with compactly supported potential. We give formulas for finding the phased scattering amplitude from phaseless near-field scattering data.
Simultaneous observation of noble gases and highly charged ions in an electron beam ion trap for accurate wavelength calibration of optical transitions
Authors: Kimura Naoki , Nakamura Nobuyuki
Published: October 2023

Spectral lines of buffer noble gases injected into an electron beam ion trap (EBIT) have recently been used as a reference to aid accurate determination of the wavelengths of optical transitions of highly charged ions (HCIs). Simultaneous observation of emission lines of HCIs along with those of neutral atoms or singly charged ions represents a reliable method for wavelength calibration that suppresses systematic uncertainties. Here, we present visible and infrared emission spectra of buffer Ne and Ar gases in an EBIT and briefly review the buffer gas calibration method. The experimental conditions required for implementing the calibration method are discussed by investigating the dependence of the emission spectra of mixtures of HCIs and noble gases on electron beam’s parameters and gas pressure.
Measurement of neutron induced reaction cross-section of 99Mo
Authors: Upadhyay Mahima , Choudhary Mahesh , Singh Namrata , Gandhi A , Sharma Aman , Bamal Sumit , Hingu Akash , Mukherjee S , Mishra G , De Sukanya , Danu L S , Sood Saurav , Prasad Sajin , Kumar Ajay , Thomas R G , Kumar A
Published: October 2023

In the present work, we have measured 98Mo(n,γ)99Mo reaction cross-section using a 7Li(p,n)7Be neutron source at 1.67 ± 0.14, 2.06 ± 0.14 and 2.66 ± 0.16 MeV neutron energies. We have employed offline γ-ray spectroscopy to measure the induced activity of the sample. The 115In(n,n’γ)115mIn reaction was used as a monitor reaction. Different attributes propagating the uncertainty in the total result, measured cross-sections with their uncertainties and correlation coefficients are given in detail in the present study. The result is compared with the data libraries, EXFOR database and theoretical model outcome from different level density models.
Elliptic flow of inclusive charged hadrons in Au+Au collisions at E
lab = 35 A GeV using the PHSD model
Authors: Bhat Waseem , Farooq Mir M , Bairathi Vipul , Bhat Towseef , Kabana Sonia , Bhat Shabir
Published: October 2023

Elliptic flow (v
2) of inclusive charged hadrons at mid-rapidity (∣η∣ < 1.0) in Au+Au collisions at E
lab = 35 A GeV using the parton hadron string dynamics (PHSD) model are presented as a function of centrality, transverse momentum (p
T) and pseudo-rapidity (η). The v
2 results are obtained using the η-sub event plane method with respect to the event plane angle (ψ
2) and participant plane angle (

ψ

2

PP

). p
T-integrated charged hadron v
2 shows a strong centrality dependence in Au+Au collisions at E
lab = 35 A GeV. The eccentricity-scaled elliptic flow (v
2/ε
2) also shows centrality dependence. The higher values of v
2/ε
2 in central collisions suggest the development of stronger collectivity. The calculations are compared with the results from Au+Au collisions at

s

NN

=
7.7

GeV

published by the STAR experiment at RHIC. We also compare the results of HSD and PHSD modes to investigate the contribution of hadronic and partonic phases of the medium on the calculated v
2. The current results serve as a prediction of the collective behavior of the matter produced in baryon-rich and moderate temperature conditions for the upcoming multi-purpose detector at the nuclotron-based Ion collider facility (NICA) and compressed baryonic matter experiment at the facility for antiproton and ion research. These predictions are also useful for interpreting data measured at relativistic heavy ion collider (RHIC) beam energy scan program.
Waste-YOLO: towards high accuracy real-time abnormal waste detection in waste-to-energy power plant for production safety
Authors: Wang He , Wang Lianhong , Chen Hua , Li Xiaoyao , Zhang Xiaogang , Zhou Yicong
Published: October 2023

Due to the danger of explosive, oversize and poison-induced abnormal waste and the complex conditions in waste-to-energy power plants (WtEPPs), the manual inspection and existing waste detection algorithms are incapable to meet the requirement of both high accuracy and efficiency. To address the issues, we propose the Waste-YOLO framework by introducing the coordinate attention, convolutional block attention module, content-aware reassembly of features, improved bidirectional feature pyramid network and SCYLLA- intersection over union loss function based on YOLOv5s for high accuracy real-time abnormal waste detection. Through video acquisition, frame-splitting, manual annotation and data augmentation, we develop an abnormal waste image dataset with the four most common types (i.e. gas cans, mattresses, wood and iron sheets) to evaluate the proposed Waste-YOLO. Extensive experimental results demonstrate the superiority of Waste-YOLO to several state-of-the-art algorithms in waste detection effectiveness and efficiency to ensure production safety in WtEPPs.
Improving ambiguity resolution with common-antenna-based dual-board receiver for low-cost real-time kinematic positioning
Authors: Jia Chun , Zou Zhaobo , Yang Fuxin
Published: October 2023

Ambiguity resolution is of critical importance to the carrier phase-based real-time kinematic (RTK) positioning method. Improving the accuracy of float ambiguities is beneficial for achieving ambiguity resolution. However, the large measurement noise from low-cost receivers will worsen the estimation accuracy of float ambiguities, which affects the ambiguity resolution performance. In this contribution, to reduce the influence of large measurement noise on ambiguity resolution for low-cost receivers, an improved RTK method for ambiguity resolution is proposed to enhance the accuracy of float ambiguities by equipping the rover receiver with common-antenna-based dual global navigation satellite system (GNSS) boards instead of only one GNSS board. First, the dual-board design can increase the measurement redundancy of the same frequency to suppress the measurement noise. Second, because the common-antenna design can form a moving zero-baseline between the dual GNSS boards, the ambiguities between them can be easily fixed. Known fixed ambiguities can be used as constraints to strengthen the positioning model. Simulation and real-world static and kinematic experiments were conducted to test the proposed method. The results demonstrate that the proposed method can improve the accuracy of float ambiguities by increasing the redundancy of the measurements and introducing the constraints of the ambiguities, and the improved accuracy is about 20%. Compared with the traditional single-board RTK method, better ambiguity resolution performance can be achieved by taking advantage of the proposed common-antenna-based RTK method.
Hardware, methodology and applications of 2+D backscatter Mössbauer spectroscopy with simultaneous x-ray and γ-ray detection
Authors: O’Brien Jack , Ahmadian Baghbaderani Hasan , Keller Frederico O , Dempsey Nora , H Lewis Laura , Stamenov Plamen
Published: October 2023

A unique method is presented for the acquisition and analysis of 57Fe backscatter Mössbauer spectra with simultaneous detection of the resonant 14.4 keV γ-rays and the characteristic 6.4 keV x-rays, using a custom-built multi-parameter analyser constructed on the basis of commercial analogue to digital converters and high-speed digital latches. The system allows for the simultaneous registration of Doppler-modulation velocities and photon energies, with up to 4096 and 8192 digital channels respectively. This arrangement is in contrast to most related systems, which detect at a single narrow energy window per detector. Samples of arbitrary atomic structure, morphology and surface topography can be studied without altering the setup or the analysis procedure, provided that the samples are at least micrometre sized. The hardware and software that are used to acquire data with minimal dead time are described and the custom and self-contained methods for post-measurement energy discrimination, background correction and velocity-axis folding are discussed. The data are fit using a general Hamiltonian model for the nuclear energy levels of 57Fe and a quantum mechanical description of the angular momentum coupling is utilised, with consideration of the crystalline and chemical disorder of the sample under examination. Three examples of distinct magnetic systems, with thicknesses ranging from

5
 
μ

m to 6 mm, that were studied using this method are presented, these are: an amorphous CoFeB-based ribbon with ultra-soft coercivity for high-frequency applications, magnetically hard Nd-Fe-B thick films on Si substrates, examined in both as-deposited and annealed states, and a sample from the nickel-rich iron meteorite NWA 6259 that contains the atomically ordered, elevated coercivity,

L

1
0

phase of FeNi, tetrataenite. The wide applicability and usefulness of this method is thus demonstrated on three distinct sample morphologies that required little to no surface preparation prior to examination.
3D point cloud global denoising algorithm based on different noise characteristics
Authors: Gou Fuqiang , Li Yonglong , Hou Chunyao , Wang Haoran
Published: October 2023

When acquiring object point cloud data by three-dimensional scanning technology, noise is generated due to instrument accuracy and external factors. Existing algorithms rarely consider the characteristics of different noises and different regional noises when solving the point cloud denoising problem, this results in a limited effect on denoising. This paper presents an algorithm for denoising based on the characteristics of different types of noise and different regions in the point cloud. The algorithm includes large-scale noise removal and small-scale noise smoothing. Remove large-scale noise points by the relationship between the local point cloud and the global point cloud. For small-scale noise, the feature regions and non-feature regions are extracted according to the normal cosine information entropy. According to the characteristics of the small-scale noise in two regions, the noise distance distribution and the optimized bilateral filtering are used to deal with the small-scale noise in two regions respectively. Comparison experiments show that our algorithm can effectively remove the noise points mixed in the normal point cloud. The accuracy of large-scale noise removal reaches 99.1%. The proposed algorithm can protect the feature areas from being over-smoothed while smoothing the small-scale noise in non-featured areas.
Development of time-resolved photoluminescence microscopy of semiconductor materials and devices using a compressed sensing approach
Authors: Baltušis Aidas , Koutsourakis George , Wood Sebastian , Sweeney Stephen J
Published: October 2023

Charge carrier lifetime is a key property of semiconductor materials for photonic applications. One of the most established methods for measuring lifetimes is time-resolved photoluminescence (TRPL), which is typically performed as a single-point measurement. In this paper, we demonstrate a new time-correlated single photon counting method (TCSPC) for TRPL microscopy, for which spatial information can be achieved without requiring point-by-point scanning through the use of a compressed sensing (CS) approach. This enables image acquisition with a single pixel detector for mapping the lifetime of semiconductors with high repeatability. The methodology for signal acquisition and image reconstruction was developed and tested through simulations. Effects of noise levels on the reliability and quality of image reconstruction were investigated. Finally, the method was implemented experimentally to demonstrate a proof-of-concept CS TCSPC imaging system for acquiring TRPL maps of semiconductor materials and devices. TRPL imaging results of a semiconductor device acquired using a CS approach are presented and compared with results of TRPL mapping of the same excitation area measured through a point-by-point method. The feasibility of the methodology is demonstrated, the benefits and challenges of the experimental prototype system are presented and discussed.
Study of sodium diffusion in silicate glasses. Molecular dynamics simulation
Authors: Thao N T , Kien P H , Yen N V , Hung P K , Noritake Fumiya
Published: October 2023

Molecular dynamics simulation is carried out to study diffusion in sodium silicate glasses (NS1, NS2, NS3, NS4) at temperatures of 973, 1173 and 1373 K. The result shows that the structure consists of network region where more than 83% of total Si and O are present, and Na-polyhedron region in which most Na-polyhedrons possess several non-bridging oxygens. The Na-polyhedron region changes slightly with temperature, and significantly with SiO2 concentration. During 150 ps the Si and O atoms vibrate around fixed points, while Na atoms move from one Na-polyhedron to another. The network region is static, while the Na-polyhedron region is seen dynamically. The glasses exhibit the dynamics heterogeneity. The simulation shows that Na atoms reside in a small part of Na-polyhedron region and move frequently through pathways consisting of polyhedrons with high local sodium density. Moreover, they move between polyhedrons often by small displacements and rarely by large jumps. We establish the expression for diffusion constant D
Na via average resident time in polyhedron t
RP and mean square displacement of Na per polyhedron δ. The dependence of D
Na on δ and lnD
Na on t
RP is found to be linear.
Numerical simulation of linear reciprocating wear mechanism of hybrid aluminum metal matrix composite using finite element method
Authors: Kumar Prakash , Kumar Binay
Published: October 2023

This work aims to analyze the wear properties of the hybrid aluminum metal matrix composites (HAMMCs) using finite element analysis (FEA). A dry sliding linear reciprocating wear mechanism is analyzed using ANSYS 19.1. Aluminum 7075 alloy and HAMMC reinforced with ZrB2 (1, 3, and 5 wt.%) and fly ash (2 wt.%) is taken as sample material. A steel ball (EN 52100) is utilized as a counterpart in the dry sliding wear properties study. The deformation of the steel ball during the wear process is assumed to be negligible. Under various circumstances, a 3D point-to-surface connection is built to analyze the dry sliding wear process. The wear depth, contact pressure, and wear volume are analyzed using FEA. The analytical results are compared with the experimental results with the help of ANSYS to analyze the process parameters. The ANOVA analysis is employed for optimization, which exhibits that the load had the most significant impact on the material’s wear rate, followed by the material’s composition and temperature. The wear depth, wear rate, and contact pressure at optimum input parameters for the HAMMCs are 0.47 μm, 11.31 × 10−6 mm3 Nm−1, and 0.33 MPa, respectively. The Simulated results support the experimental results, and the average error is 9.82%.
Editorial: Focus on green nanomaterials for a sustainable internet of things
Authors: Pecunia Vincenzo , Occhipinti Luigi G , Cloutier Sylvain G , Sun Shuhui , Grace Andrews Nirmala , Leong Wei Lin
Published: October 2023

In the dynamic landscape of the Internet of Things (IoT), where smart devices are reshaping our world, nanomaterials can play a pivotal role in ensuring the IoT’s sustainability. These materials are poised to redefine the development of smart devices, not only enabling cost-effective fabrication but also unlocking novel functionalities. As the IoT is set to encompass an astounding number of interconnected devices, the demand for environmentally friendly nanomaterials takes center stage. This Focus Issue spotlights cutting-edge research that explores the intersection of nanomaterials and sustainability. The collection delves deep into this critical nexus, encompassing a wide range of topics, from fundamental properties to applications in devices (e.g. sensors, optoelectronic synapses, energy harvesters, memory components, energy storage devices, and batteries), aspects concerning circularity and green synthesis, and an array of materials comprising organic semiconductors, perovskites, quantum dots, nanocellulose, graphene, and two-dimensional semiconductors. Authors not only showcase advancements but also delve into the sustainability profile of these materials, fostering a responsible endeavour toward a green IoT future.
Controlled synthesis and photocatalytic hydrogen evolution activities of cobalt carbides with different phase compositions
Authors: Wang Longfei , Yu Qingguo , Liu Yimin , Fujita Toyohisa , Wei Yuezhou , Wang Xinpeng , Zeng Deqian
Published: October 2023

Cobalt carbides are emerging as promising materials for various magnetic and catalytic applications. However, exploring dedicated cobalt carbides with optimal catalytic properties via adjusting phase compositions remains a significant challenge. Herein, three different cobalt carbides, Co
x
C (Co2C-Co3C), Co2C-Co, and Co3C, were successfully prepared using a facile one-pot green method. The phase compositions of cobalt carbides could be easily controlled by varying the cobalt-based precursors and carbon sources. More remarkably, three different cobalt carbides could serve as reduction cocatalysts decorated CdS for improved hydrogen production under visible light. Intriguingly, the obtained Co3C/CdS nanocomposite displayed the highest photocatalytic hydrogen evolution activity among the three composites and superior photocatalytic stability. This work provides a fundamental approach to tuning the photocatalytic properties of cobalt carbides for energy conversion fields.
Experimental validation in a neutron exposure frame of the MINAS TIRITH for cell damage simulation
Authors: Thibaut Y , Gonon G , Martinez J S , Petit M , Babut R , Vaurijoux A , Gruel G , Villagrasa C , Incerti S , Perrot Y
Published: October 2023

In the domains of medicine and space exploration, refining risk assessment models for protecting healthy tissue from ionizing radiation is crucial. Understanding radiation-induced effects requires biological experimentations at the cellular population level and the cellular scale modeling using Monte Carlo track structure codes. We present MINAS TIRITH, a tool using Geant4-DNA Monte Carlo-generated databases to study DNA damage distribution at the cell population scale. It introduces a DNA damage location module and proposes a method to convert double-strand breaks (DSB) into DNA Damage Response foci. We evaluate damage location precision and DSB-foci conversion parameters. MINAS TIRITH’s accuracy is validated against γ-H2AX foci distribution from cell population exposed to monoenergetic neutron beams (2.5 or 15.1 MeV) under different configurations, yielding mixed radiation fields. Strong agreement between simulation and experimental results was found demonstrating MINAS TIRITH’s predictive precision in radiation-induced DNA damage topology. Additionally, modeling intercellular damage variability within a population subjected to a specific macroscopic dose identifies subpopulations, enhancing realistic fate models. This approach advances our understanding of radiation-induced effects on cellular systems for risk assessment improvement.
Simulation of performance enhancement of GaN-based VCSELs by composition gradient InGaN last-quantum barrier
Authors: Wang Ya-chao , Yang Tao , Shi Lei , Chen Yan-hui , Mei Yang , Zhang Bao-Ping
Published: October 2023

Electron leakage in the active region decreases the internal quantum efficiency and impedes the performance of gallium nitride (GaN)-based vertical-cavity surface-emitting lasers (VCSELs). In this study, we propose a novel InGaN last-quantum barrier (LQB) structure with gradient indium (In) composition, and the device performance was simulated by the commercial software PICS3D. Compared with the device with conventional GaN LQB, the electron leakage is greatly reduced and the hole injection efficiency is also improved by the graded LQB structure. Consequently, the threshold current is reduced by 44%, and output power is increased by 392% in GaN-based VCSEL based on composition gradient InGaN LQB. The composition gradient InGaN can also allow us to increase the thickness of the LQB in epitaxy without degrading the carrier injection efficiency due to the reduced polarization in the LQB. The results of this study suggest that the composition gradient InGaN LQB is promising for the realization of high-performance GaN-based VCSELs.
Adaptive protocols for SU(1,1) interferometers to achieve ab initio phase estimation at the Heisenberg limit
Authors: Liu Mingchen , Zhang Lijian , Miao Haixing
Published: October 2023

The precision of phase estimation with interferometers can be greatly enhanced using non-classical quantum states, and the SU(1,1) interferometer is an elegant scheme, which generates two-mode squeezed state internally and also amplifies the signal. It has been shown in Anderson et al (2017 Phys. Rev. A 95 063843) that the photon-number measurement can achieve the Heisenberg limit, but only for estimating a small phase shift. We relax the constraint on the range of phase by considering two adaptive protocols: one also uses the photon-number measurement with a specially tuned sequence of feedback phase; the other implements the yet-to-be-realized optimal measurement but without fine tuning.
Applications of different machine learning methods on nuclear charge radius estimations
Authors: Bayram Tuncay , Yeşilkanat Cafer Mert , Akkoyun Serkan
Published: October 2023

Theoretical models come into play when the radius of nuclear charge, one of the most fundamental properties of atomic nuclei, cannot be measured using different experimental techniques. As an alternative to these models, machine learning (ML) can be considered as a different approach. In this study, ML techniques were performed using the experimental charge radius of 933 atomic nuclei (A ≥ 40 and Z ≥ 20) available in the literature. In the calculations in which eight different approaches were discussed, the obtained outcomes were compared with the experimental data, and the success of each ML approach in estimating the charge radius was revealed. As a result of the study, it was seen that the Cubist model approach was more successful than the others. It has also been observed that ML methods do not miss the different behavior in the magic numbers region.
Bifurcation analysis, chaotic analysis and diverse optical soliton solutions of time-fractional (2+1) dimensional generalized Camassa-Holm Kadomtsev-Petviashvili equation arising in shallow water waves
Authors: Gupta Rajesh Kumar
Published: October 2023

This paper presents a study on (2+1) generalized Camassa-Holm Kadomtsev-Petviashvili equation, which is used to describe the behavior of shallow water waves in nonlinear media. The considered equation provides a more accurate description of wave behavior compared to linear wave equations and can account for wave breaking and other nonlinear effects. This model can be used to describe and study the behavior of nonlinear waves such as rogue waves in complex fluid dynamics scenarios. This includes the behavior of waves in stratified fluids, nonlinear dispersive media and wave interactions in fluid flows with varying velocities and densities. The bifurcation analysis of the governing equation has been performed using the planar dynamical system method. The chaotic behavior of the dynamical system has been examined by utilizing various techniques such as time series analysis and the construction of 2D and 3D phase space trajectories. Furthermore, the introduction of a perturbed term has resulted in the observation of chaotic and quasi-periodic behaviors across a range of parameter values. The considered equation has been reduced to ordinary differential equation by performing symmetry reduction. The Kudryashov method has been used to obtain the exact solution of reduced equation. The single soliton solution of governed equation has been obtained by using Hirota method and impact of fractional parameter on the obtained solution has been studied using graphical representation. The extended sinh-Gordon equation expansion method and modified generalized exponential rational function method have been exploited to obtain dark, bright and singular soliton solutions of considered equation. The motivation for this study arises from the need to understand and analyze the complex dynamics of shallow water waves in nonlinear media with a particular focus on the (2+1) generalized Camassa-Holm Kadomtsev-Petviashvili equation. By performing symmetry reduction and applying various analytical methods, we aim to unravel the intricate behavior and soliton solutions of considered equation, contributing to the broader understanding of nonlinear wave phenomena.
Numerical study of alpha particle loss with toroidal field ripple based on CFETR steady-state scenario
Authors: Li 李 Niuqi 钮琦 , Xu 徐 Yingfeng 颖峰 , Zhong 钟 Fangchuan 方川 , Zhang 张 Debing 德兵
Published: October 2023

Effects of plasma equilibrium parameters on the alpha particle loss with the toroidal field ripple based on the CFETR steady-state scenario have been numerically investigated by the orbit-following code GYCAVA. It is found that alpha particle losses decrease and loss regions become narrower with the plasma current increasing or with the magnetic field decreasing. It is because the ripple stochastic transport and the ripple well loss of alpha particle are reduced with the safety factor decreasing. Decrease of the plasma density and temperature can reduce alpha particle losses due to enhancement of the slowing-down effect. The direction of the toroidal magnetic field can significantly affect heat loads induced by lost alpha particle. The vertical asymmetry of heat loads induced by the clockwise and counter-clockwise toroidal magnetic fields are due to the fact that the ripple distribution is asymmetric about the mid-plane, which can be explained by the typical orbits of alpha particle. The maximal heat load of alpha particle for the clockwise toroidal magnetic field is much smaller than that for the counter-clockwise one.
Research on Ultra-wide Bandwidth Low-frequency Signal Channelization for Xinjiang 110 m Radio Telescope
Authors: Zhang Hai-Long , Zhang Ya-Zhou , Zhang Meng , Wang Jie , Li Jian , Ye Xin-Chen , Pei Xin
Published: October 2023

Aiming at the subband division of ultra-wide bandwidth low-frequency (UWL) signal (frequency coverage range: 704–4032 MHz) of the Xinjiang 110 m QiTai radio Telescope (QTT), a scheme of ultra-wide bandwidth signal is designed. First, we analyze the effect of different window functions such as the Hanning window, Hamming window, and Kaiser window on the performance of finite impulse response (FIR) digital filters, and implement a critical sampling polyphase filter bank (CS-PFB) based on the Hamming window FIR digital filter. Second, we generate 3328 MHz simulation data of ultra-wideband pulsar baseband in the frequency range of 704–4032 MHz using the ultra-wide bandwidth pulsar baseband data generation algorithm based on the 400 MHz bandwidth pulsar baseband data obtained from Parkes CASPSR observations. Third, we obtain 26 subbands of 128 MHz based on CS-PFB and the simulation data, and the pulse profile of each subband by coherent dispersion, integration, and folding. Finally, the phase of each subband pulse profile is aligned by non-coherent dedispersion, and to generate a broadband pulse profile, which is basically the same as the pulse profile obtained from the original data using DSPSR. The experimental results show that the scheme for the QTT UWL receiving system is feasible, and the proposed channel algorithm in this paper is effective.
A new paradigm for fast and repetitive chirping of Alfvén eigenmodes
Authors: Cheng Junyi , Zhang Wenlu , Lin Zhihong , Bao Jian , Dong Chao , Cao Jintao , Li Ding
Published: October 2023

A novel 2D nonlinear dynamical paradigm is constructed to interpret the fast and repetitive frequency chirping and amplitude oscillation of Alfvén eigenmodes excited by energetic particles in fusion plasmas as observed in global gyrokinetic simulations. In this non-perturbative paradigm of the collisionless phase-space dynamics, wave-particle resonant interactions cause the phase-space structure to continuously twist and fold, leading to the repetitive excitation and decay of the Alfvén eigenmode. The radial (perpendicular to the dominant wave-particle interaction) dependence of the mode amplitude and toroidal precessional drifts of the energetic particles leads to the 2D dynamics of wave-particle interactions, which is found to be responsible for the repetitive process of formation and destruction of the mode structure.
A cooperative game-based vulnerability assessment method for distribution lines in typhoon weather
Authors: Fan Xiaoyue , Hou Shuainan
Published: October 2023

Identification and protection of vulnerable lines is the key point of typhoon disaster prevention in distribution networks in coastal areas. This paper proposes a comprehensive lines vulnerability assessment method based on combined weight using cooperative games. Firstly, a distribution line vulnerability evaluation index system is constructed from four aspects: line fault probability, line loss value, line electric betweenness, and line degree. Secondly, the entropy method and CRITIC weight method are used to calculate the weights of each evaluation index in the evaluation system, respectively, and the cooperative game method is used to combine the two weights. Finally, the combined weight is used to evaluate the vulnerability of the line. The power distribution system in a certain area is used for the example simulation, and the key vulnerable lines of the distribution network can be identified, which shows the rationality and effectiveness of the proposed method.