bluuebunny/crossref_metadata_2025 huggingface dataset:
Nonlinear response of magnetization obeying inertial dynamics to superimposed dc and ac fields and dynamic magnetic hysteresis
Authors: Titov Sergei V. , Dowling William J. , Titov Anton S. , Fedorov Andrey S.
Published: March 2024

The nonlinear ac stationary responses of magnetization and the dynamic magnetic hysteresis of ferromagnetic particles with uniaxial anisotropy acted on by both external dc and ac magnetic fields are evaluated by employing the inertial Landau–Lifshitz–Gilbert equation. Analytical expressions are obtained for the components of the second- and third-order nonlinear susceptibility tensors using the perturbation method. The dynamic nonlinear susceptibility strongly depends on the dc field strength. The effect of inertia on the area and slope of the dynamic magnetic hysteresis loop is demonstrated. In addition to nutation resonance, the main nonlinear effects previously observed in the ferromagnetic resonance region (frequency doubling and appearance of weak subharmonic resonance peaks) are predicted in the nutation resonance frequency region.
A novel nanocomposite of MXene/cadmium azide with high detonation performance
Authors: Zhang Lei , Cai Junjie , Wei Chunqiang , Xie Mingwei , Peng Yue , Yuan Xiaoxia , Ma Hongliang
Published: March 2024

A novel MXene/cadmium azide nanocomposite with a low input energy and high output power is designed by self-assembly of Cd ions on the MXene layers and subsequent in situ azidation in a solution reaction. The research result shows that cadmium azide nanoparticles with a uniform size of ∼50 nm are well dispersed on the MXene nanosheet’s surface, which is benefited from the rich functional groups on the MXene surface that can effectively immobilize and prevent the aggregation of the nanoparticles through electrostatic interaction. The thermal decomposition temperature (378.42 °C) and crystal structure of cadmium azide show no noticeable change after hybridizing with the MXene; more positively, the required input energy of the MXene/cadmium azide nanocomposite is significantly reduced, which is verified by its electric initiation input voltage of just 4.65 V. In addition, detonation can be realized by loading a less amount of the MXene/cadmium azide nanocomposite. These results demonstrate that the MXene/cadmium azide nanocomposite has the potential to be used as detonators in high-temperature environments.
Emerging vegetable crop diseases and their management options
Authors: Gilardi Giovanna , Pugliese Massimo , Garibaldi Angelo , Gullino Maria Lodovica
Published: March 2024

Vegetable crops are economically important throughout the world and they all share some common features, such as high value, globalisation of the seed market, continuous intensification and innovation of their production systems, the presence of a high number of crops and varieties, and a limited availability of chemical pesticides for their disease management. In this review, we focus on fungal plant pathogens, although several diseases caused by bacteria are becoming important. Many diseases caused by soilborne pathogens, such as
Fusarium oxysporum
(different
formae speciales
),
Sclerotinia sclerotiorum
,
Rhizoctonia solani, Pythium
spp. and
Phytophthora
spp., become more severe over the last few years. Many of these diseases can be considered the consequence of the profound changes that soil disinfestation has undergone since the use of methyl bromide was prohibited in 2005. In the meantime, new hosts have been detected for diseases caused by foliar pathogens (
Alternaria
spp.,
Stemphylium
spp.
Fusarium equiseti
,
Albifimbria verrucaria
,
Paramyrothecium roridum
), often as a consequence of climate change. The phytopathological situations of vegetable crops is discussed hereafter, with special emphasis on Italy, which is one of the most important vegetable production countries in Europe (not worldwide). The evolution of some diseases as a possible consequence of the current limitations in the use of chemicals, of the globalisation of the markets and/or of climate change is critically discussed. The disease management options that are currently available (e.g. the use of healthy planting material, host resistance, soil health, soilless systems, biological control, and integrated pest management) are discussed.
Local data inverse problem for the polyharmonic operator with anisotropic perturbations
Authors: Bhattacharyya Sombuddha , Kumar Pranav
Published: March 2024

In this article, we study an inverse problem with local data for a linear polyharmonic operator with several lower order tensorial perturbations. We consider our domain to have an inaccessible portion of the boundary where neither the input can be prescribed nor the output can be measured. We prove the unique determination of all the tensorial coefficients of the operator from the knowledge of the Dirichlet and Neumann map on the accessible part of the boundary, under suitable geometric assumptions on the domain.
Image analysis and resolution for detection-based synthetic-aperture passive source localization
Authors: Cheney Margaret , Scharf Louis , Rhilinger Matthew , Moore Cole , Celestin Andre
Published: March 2024

This paper follows a detection-theoretic approach for using synthetic-aperture measurements, made at multiple moving passive receivers, in order to form an image showing the locations of stationary sources that are radiating unknown electromagnetic or acoustic waves. The paper starts with a physics-based model for the propagating fields, and, following the general approach of McWhorter et al (2023 arXiv:2302.06816, IEEE Open J. Signal Process.
4 437–51), derives a detection statistic that is used for the image formation. This detection statistic is a quadratic function of the data. Each point in the scene is tested as a possible hypothesized location for a source, and the detection statistic is plotted as a function of location. Because this image formation process is nonlinear, the standard linear methods for determining resolution cannot be applied. This paper shows how to analyze the detection image by first writing the noiseless image as a coherent sum of shifted complex ambiguity functions of the source waveform. The paper then develops a technique for calculating image resolution; resolution is found to depend on the sensor-source geometry and also on the properties (bandwidth and temporal duration) of the source waveform. Optimal filtering of the image is given, but a simple example suggests that optimal filtering may have little effect. Analysis is also given for the case in which multiple sources are present.
An adaptive anisotropic bilateral filtering method for mesh data in scale space
Authors: Su Ling-Jie , Li Wen-Long , Cheng Yu-Qi , Wang Dong-Fang , Jiang Cheng , Yang Wen-Tao , Zhang Hai-Wen , Xu Wei
Published: March 2024

Three-dimensional mesh data of parts, such as blades and engine bodies, have been widely used in industrial fields. Due to the different kinds of noise during mesh acquisition and the machining deficiency of parts, the mesh quality tends to be insufficient for subsequent operations. Therefore, mesh denoising is a necessary and critical procedure to improve mesh quality. Existing methods commonly apply geometry features smoothing, which may also create unexpected results, such as volume shrinkage and blurring of sharp edges. This paper proposed an adaptive anisotropic bilateral filtering method for mesh data in scale space. Firstly, the mesh is decomposed into a smooth base with low frequency and a height vector field with high frequency based on scale space theory. The denoising of the vertex spatial field is transformed into the denoising of the height vector field, aiming to only consider high-frequency information. Secondly, the bilateral filter scheme with the anisotropic Gaussian kernel is proposed to denoise the height vector field, removing noise mixed with features. The parameters in the bilateral filter scheme are chosen adaptively by maximizing the designed probability density function. The mean square angular error of the proposed method is less than 0.15 rad, which is superior to the general-purpose algorithms, for instance, Laplacian filtering, bilateral mesh filtering and bilateral normal filtering algorithm.
Small data-driven semantic segmentation of wear debris in ferrography images
Authors: Xi Yinhu , Zhang Nan , Li Bo
Published: March 2024

The segmentation of wear debris images is a prerequisite for ferrographic analysis, and uncertainties and errors in wear debris segmentation will inevitably affect the subsequent analysis. In this work, a small-data semantic segmentation model of wear debris images is constructed based on HRNetv2 for ferrography images acquired by using an online visual ferrography. A major advantage of the current model is that fewer ferrography images are required for training, and fewer iterations are needed. The current work is performed for ferrography images with both clean oil and contaminated oil, and good segmentation results can be found. Specially, the experimental results show that the current model can achieve accurate segmentation of wear debris images with mean intersection over union values of 91.47% and mean pixel accuracy values of 96.48%.
An equation for the ‘weather glass’
Authors: Jewess Michael
Published: March 2024

The ‘weather glass’, containing air and (usually) water, is a compact barometer, less accurate but more convenient than the Torricellian barometer of 1644. The weather glass pre-dates the Torricellian barometer, and coexisted with it until it was out-competed from about 1860 by the more accurate, comparably compact aneroid barometer. Today, the weather glass is sold as an elegant interior decoration and is also constructible in a student laboratory. Elementary physics allows one to model its response to changing pressure at constant temperature and also the adjustments that need to be made if the temperature varies. In an air- and water-containing weather glass, the principal factor affecting movements of the water level is the expansion and contraction of the atmospheric nitrogen, oxygen, and argon in a headspace above the water, well represented by the ideal gas law. The water acts primarily as a piston allowing the expansion and contraction to be observed. In contrast, Torricellian and aneroid barometers respond directly to the pressure difference between the atmosphere and a vacuum.
A mechanical device to demonstrate the composition of two simple harmonic motions
Authors: Hu Lian
Published: March 2024

The slot link mechanism can project uniform rotation to a simple harmonic motion (SHM), based on which, the device including two sliding table systems has been prepared. These two sliding table systems can be stacked up and down, and each of them can produce a tunable mechanical SHM using a stepper motor. When the upper sliding table system is attached to the lower one and both are turned on, the motion of the sliding table of the upper component is the composition of the two SHMs. With the help of a self-powered LED, a violet laser, and a movable phosphorescent foil, this mechanical device can visualize the composition of the SHMs in the same and mutual perpendicular directions including the beat phenomenon and Lissajous figures. In addition to demonstrating several typical compositions of two SHMs, this device can also highlight the vector characteristics of mechanical vibration and demonstrate the tilted Lissajous figures.
A spectacular demonstration of energy transformation in an internal combustion engine
Authors: Holovko Mykola , Kryzhanovskyi Serhii , Matsyuk Viktor
Published: March 2024

The structure and operating principle of a four-stroke internal combustion engine are usually demonstrated using the cut-away model of an internal combustion engine or its computer animation. However, by observing the operation of the engine mechanism, the understanding of the main essence, which consists of the transformation of thermal energy from the combustion of gasoline into the mechanical energy of the piston movement is lost. This work describes the demonstration of the ignition and combustion of the fuel mixture and the transformation of thermal energy generated by the combustion of gasoline into the mechanical energy of the piston. A paper rocket is used instead of a piston for the spectacle of the experiment. This demonstration does not leave anyone from the audience indifferent. The dependence of rocket flight height on the mass of burned gasoline was established.
Motion of a metal nut sliding around a vertical loop
Authors: Cross Rod
Published: March 2024

An experiment is described where a metal nut was allowed to slide from the top to the bottom of a vertical wire loop. An interesting feature is that the normal reaction force on the nut decreases to zero and reverses direction before the nut reaches the bottom of the loop.
A blurring correction method suitable to analyze quantitative x-ray images derived from energy-resolving photon counting detector
Authors: Kobayashi Daiki , Hayashi Hiroaki , Nishigami Rina , Maeda Tatsuya , Asahara Takashi , Kanazawa Yuki , Katsumata Akitoshi , Kimoto Natsumi , Yamamoto Shuichiro
Published: March 2024

Objective. The purpose of this study is to propose a novel blurring correction method that enables accurate quantitative analysis of the object edge when using energy-resolving photon counting detectors (ERPCDs). Although the ERPCDs have the ability to generate various quantitative analysis techniques, such as the derivations of effective atomic number (Z
eff) and bone mineral density values, at the object edge in these quantitative images, accurate quantitative information cannot be obtained. This is because image blurring prevents the gathering of accurate primary x-ray attenuation information. Approach. We developed the following procedure for blurring correction. A 5 × 5 pixels masking region was set as the processing area, and the pixels affected by blurring were extracted from the analysis of pixel value distribution. The blurred pixel values were then corrected to the proper values estimated by analyzing minimum and/or maximum values in the set mask area. The suitability of our correction method was verified by a simulation study and an experiment using a prototype ERPCD. Main results. When Z
eff image of aluminum objects (Z
eff = 13) were analyzed without applying our correction method, regardless of raw data or correction data applying a conventional edge enhancement method, the proper Z
eff values could not be derived for the object edge. In contrast, when applying our correction method, 82% of pixels affected by blurring were corrected and the proper Z
eff values were calculated for those pixels. As a result of investigating the applicability limits of our method through simulation, it was proven that it works effectively for objects with 4 × 4 pixels or more. Significance. Our method is effective in correcting image blurring when the quantitative image is calculated based on multiple images. It will become an in-demand technology for putting a quantitative diagnosis into actual medical examinations.
One-dimensional simulation and validation of divertor detachment induced through nitrogen seeding on HL-2A
Authors: Zhou Yulin , Dudson Benjamin , Wu Ting , Wang Zhanhui , Xia Tianyang , Zhong Cailai , Gao Jinming , Du Hailong , Fan Dongmei
Published: March 2024

Divertor detachment is a promising method to solve the power exhaust problem in tokamak devices or even in future magnetic fusion reactors. In this work, a detachment experiment (HL-2A shot #38008) with mixed gas seeding (60% nitrogen and 40% deuterium) is simulated using the SD1D module in BOUT++. In the process from attachment to detachment, the target electron temperature and the target ion saturation current in simulations are found to be consistent with the experimental results measured by Langmuir probes on the target plate. In order to understand the underlying detachment mechanism on HL-2A, this work analyses the role of different particle species in the cases with different seeding rates. It shows that the plasma density varies little and the density of neutrals (

D

and

D

2

) slightly decreases with the increase of nitrogen seeding rate, such that plasma–neutral interactions cannot effectively reduce plasma energy and plasma momentum in the divertor. The case with a high seeding rate predicts that increasing seeding rate cannot reach a target temperature lower than

2.5

eV

, which is the required temperature for strong plasma–molecule interactions. Thus, the plasma–molecule interactions may not be important in the divertor during nitrogen seeding. This work also studies the parallel forces including (1) force due to the parallel electric field, (2) friction forces, (3) ion- and electron-thermal forces, and (4) collisional reactions (e.g. charge exchange recombination and ionisation). It is found that the friction force between nitrogen ions and other particle species (primarily

D

+

) is the dominant force towards the target, while ion- and electron-thermal forces are the dominant force pushing nitrogen ions back to upstream. Parallel forces determine the parallel distribution of nitrogen impurities, and therefore decide the region of nitrogen radiation.
Validated edge and core predictions of tungsten erosion and transport in JET ELMy H-mode plasmas
Authors: Kumpulainen H A , Groth M , Brezinsek S , Casson F , Corrigan G , Frassinetti L , Harting D , Romazanov J ,   JET contributors
Published: March 2024

Predictive edge and core simulations of tungsten (W) erosion and transport in JET ITER-like wall plasmas are shown to be consistent with the experimentally inferred W density in the main plasma, within the uncertainty inherited from the measurements of the deuterium plasma conditions and from the W density measurements. The ERO2.0 code is applied to predicting the W erosion and edge transport, whereas JINTRAC predicts W transport from the pedestal top to the core plasma. The studied plasma scenarios range from L-mode to the highest-performance deuterium ELMy H-mode in JET.
Flexible field-effect transistors with high-quality and uniform single-layer graphene for high mobility
Authors: Park Hyunjin , Kwon Jimin , Seo Jihyung , Kim Kiho , Kim Yun Ho , Jung Sungjune
Published: March 2024

In this work, a fully flexible graphene field-effect transistor with high carrier mobility is reported. Patterned high-quality and uniform single-layer graphene films are successfully realized by combining the selective growth on a patterned copper foil and the direct transfer method to minimize degradation factors. The selectively grown single-layer graphene is directly transferred to the target substrate through the deposition of poly-para-xylylene (Parylene) C. The quality of the graphene films is confirmed by Raman spectroscopy. The analysis reveals that the use of Parylene C as the substrate, gate dielectric, and encapsulation layer has the advantage of reducing the scattering by the optical phonons and charge puddles. The estimated residual carrier density is 1.72 × 1011 cm−2, and the intrinsic hole and electron carrier mobilities are found to be as high as 10 260 and 10 010 cm2 V−1 s−1, respectively. This study can pave the way for the development and mass production of high-performance and fully flexible graphene electronics.
Normally-off GaON/p-GaN gate HEMTs with selective plasma oxidation: from structural characterization, performance improvement to physical mechanism
Authors: Wu Nengtao , Xing Zhiheng , Luo Ling , Li Guoqiang
Published: March 2024

In this letter, a p-GaN gate high-electron-mobility transistor (HEMT) with a high threshold voltage and better gate reliability was demonstrated by using selective plasma oxidation (SPO) and an additional low-temperature annealing step before gate metal is evaporated. After the SPO, a gallium oxynitride (GaON) dielectric layer was formed on the surface of p-GaN under the gate metal, and was studied by x-ray photoelectron spectroscopy (XPS), secondary ion mass spectrometry, high-resolution transmission electron microscopy and energy dispersion spectroscopy. In addition, the fabricated metal/GaON/p-GaN gate HEMT exhibited a large threshold voltage (V
TH) improvement from 1.46 V to 2.47 V. Furthermore, the forward gate breakdown voltage (V
GS,BD) increased from 7.55 V to 11.10 V, and the maximum forward gate operating voltage (V
GS-max) significantly improved from 5.0 V to 7.80 V for a ten-year lifetime with a 63.2% failure rate. Kelvin probe force microscopy reveals that the surface potential increased after SPO, and the shift of valence band maximum obtained by XPS spectra was 0.7 eV lower than that of the p-GaN, which further improves the Schottky barrier height at the gate metal/GaON interfaces to holes, thereby improving V
TH and reducing I
GS of the device. As a barrier layer, GaON suppressed the injection of carrier into the depletion region under a high electric field and enhanced the reliability of the gate.
Effect of two-dimensional non-local screening on characteristics of transition metal dichalcogenide monolayers
Authors: Mughnetsyan Vram , Manaselyan Aram , Movsisyan Ashot , Kirakosyan Albert
Published: March 2024

On the basis of the theory developed for the dielectric function of atomic thin layer insulating materials (Cudazzo et al 2011 Phys. Rev. B 84 085406), some characteristics of transition metal dichalcogenide monolayers are calculated in the framework of variational method. This method initially was designed to work for very weak or strong magnetic fields, but it is also in very good agreement with the numerical results obtained for intermediate magnetic fields. The expressions of the energy and effective radius of the ground impurity state, depending on the effective screening parameter of the problem, are obtained both without and with magnetic fields.
Numerical and experimental assessment of tilted-helical fiber orientation effects on deformation of pneumatic soft actuators
Authors: Shabani Majid
Published: March 2024

Pneumatic actuation of fiber-reinforced soft-material slender structures, and specifically inflatable cylinders, plays a key role in soft robotics, particularly for generating sought deformations in terms of, e.g. elongation, expansion, torsion, and bending. Fiber-reinforced tubes were widely investigated, in particular by considering regular helical patterns for the fibers, and multiple sets of fibers were introduced for achieving relatively richer deformations such as coiling (i.e. combined bending and torsion). However, coiling can be obtained even by introducing a single tilted-helical fiber, thus potentially simplifying actuator design and implementation. Therefore, in this study, we numerically investigated the effect of fiber orientation on the coiling behavior of tilted-helical fiber-reinforced cylindrical actuators. Specifically, we used finite element numerical simulations to determine the effect of fiber pitch and tilt angle on the curvature and twist angle of an inflated cylindrical actuator, and we assessed numerical results based on corresponding experiments. Finally, we addressed a preliminary design chart based on the inverse map linking coiling to the corresponding pitch and tilt angle. Our results take an initial step for the design of tilted-helical fiber-reinforced actuators, with potential application to a wider class of inflatable soft actuators to program a desired coiled configuration through the integration of a single tilted-helical fiber.
Flutter analysis of laminated fiber-reinforced magnetorheological elastomer sandwich plate resting on an elastic foundation using an improved first-order shear deformation theory
Authors: Aboutalebi Reza , Eshaghi Mehdi
Published: March 2024

Magnetorheological elastomers (MREs) are polymers with viscoelastic properties that can be adjusted by manipulating the magnetic field. When MREs are combined with reinforcing fabrics, a new category of materials known as MRE composites (MRECs) can be created, which not only possess the characteristics of MREs but also enhance their rigidity. This study focuses on investigating the supersonic aeroelastic instability of a rectangular sandwich plate with a laminated MREC core layer and functionally graded materials with porosities as face layers. Additionally, the sandwich plate is supported by an elastic foundation and subjected to supersonic airflow. This investigation presents an improved first-order shear deformation theory, postulating a parabolic distribution of shear stresses. Consequently, the transverse shear stresses are rendered as zero at the surface of every individual layer; thus, the requirement for shear correction in this theory is eliminated. In addition, 8-node elements are implemented to circumvent the necessity for distinct handling of shear-locking. The aeroelastic pressure acting on the structure is considered using first-order piston theory. Micromechanical approaches, such as Halpin‐Tsai and rule of mixture approaches, are employed to determine the effective mechanical properties of the core and face layers. The dynamic equations of the structure are derived using Hamilton’s principle and the finite element method. The study also examines the impact of different magnetic fields, fiber volume fraction, elastic foundation factors, layering angles, geometry, and boundary conditions on flutter frequency.
Hydrostatic pressure and temperature effects on nonlinear optical properties in harmonic-Gaussian asymmetric double quantum wells
Authors: Sayrac M , Dakhlaoui H , Mora-Ramos M E , Ungan F
Published: March 2024

The paper examines the linear and non-linear optical characteristics of an electron in harmonic Gaussian asymmetrical double quantum wells, taking into account thermodynamic variables such as temperature and hydrostatic pressure. Numerical calculations by considering the effective mass and parabolic band approximation are performed. The electron contained within an asymmetric double well generated by the sum of a parabolic and Gaussian potential has its eigenvalues and eigenfunctions determined using the diagonalization approach. For nonlinear optical coefficients, the density matrix expansion is used. Wavefunctions and energy levels vary as an effect of the applied fields. In harmonic Gaussian asymmetrical double quantum wells, the total optical absorption coefficient (TOAC), the relative refractive index changes (RRIC), and second harmonic generation (SHG) have all been theoretically investigated. The magnitude and position of the resonant peaks are significantly influenced by the hydrostatic pressure and temperature effects. With controllable coupling and externally applied hydrostatic pressure and temperature, the potential model presented in this study can be used to simulate and manipulate the optical and electronic properties of the asymmetric double-quantum heterostructures, such as double quantum dots and wells.
Dynamics of small precession orbit of a massive-charged particle in five-dimensional Reissner-Nordström spacetime model
Authors: Alamsyah Rangga P , Fitriani Arine , Aninda Meini , Saptari Sitti A , Alatas Husin
Published: March 2024

This report discusses the dynamics of the small precession orbit of a massive-charged particle by using the Reissner-Nordström metric with an additional spatial dimension. The event horizon of a massive-charged object in the 5–dimension was smaller than that in the 4–dimension. The difference in the size of the massive-charged object event horizon has implications for the spacetime region that can trap massive-charged particles in bound orbits. The spacetime region in the 5–dimension was narrower than that in the 4–dimension. Based on a specific condition, we found that the small precession orbital formalism of massive-charged particles in the 5–dimension implies smaller orbital precession fluctuations than those in the 4–dimension. We applied a dynamical system approach to analyze the dynamics of related small precession motions.
Investigation of facet evolution on Si surfaces bombarded with Xe ions
Authors: Hans Sukriti , Kumar Parida Basanta , Augustine Sebin , Pachchigar Vivek , P Sooraj K , Ranjan Mukesh
Published: March 2024

This study investigates the formation of facets on Si surface under Xe ion irradiation using an ion energy of 0.5 keV. By examining the effects of ion incidence angle (60° –85°), fluence (4.5 × 1018 to 1.35 × 1019 ions/cm2), and temperature (RT to 200 ◦C), we explore the evolution of facets. The surface roughness displays a distinct trend, reaching its peak when the ion incidence angle is 80°, which indicates the formation of faceted structures due to a sudden change in roughness. Additionally, temperature studies highlight the important role of temperature in enhancing facet arrangement. To support experimental findings, numerical simulation using Anisotropic Kuramoto-Sivashinsky (AKS) equation is employed. These simulations provide valuable insights into the dynamics of facet evolution, allowing us to better understand how curvature-dependent sputtering yield, dispersion, and diffusion collectively influence the formation and morphology of facets on the Si surface under Xe ion irradiation.
A deep learning approach for reduce CSI feedback overhead in massive MIMO
Authors: Jianbin Xue , Jiamin Gao
Published: March 2024

The Massive MIMO system in FDD communication mode is still one of the indispensable technologies in future cellular communication systems. In order to reduce CSI feedback overhead and enhance the quality of CSI channel reconstruction, this paper proposes a RiCsiNet network model and designs an iNetBlock module with larger convolutional kernels and a wider network structure. By connecting parallel convolution kernels of 1 × 1, 3 × 3, 5 × 5, and 7 × 7, both the width of the network and the receptive field are increased simultaneously, enabling calculation of different feature details at each layer. The compressed CSI is accurately estimated through residual connections at the BS end. The network model proposed in this paper, when considering both the model parameter size and the estimated CSI accuracy, outperforms the existing algorithm model in the NMSE index of 70%. In this paper, we verify that using different learning rate decay algorithms to train the model, a good learning rate decay algorithm can effectively improve the quality of the model, the best result is 12% higher than the worst result. Furthermore, we demonstrate that training different network models with varying amounts of data can not only save time but also maximize CSI channel estimation quality on the BS side. Finally, the RiCsiNet model was verified using different SNR under COST2100 channel model. QuaDRiGa data sets with different truncated subcarriers are used to verify the RiCsiNet model. The CSI estimated by the RiCsiNet model all showed high accuracy.
Optical and structural properties of chlorophyll a aggregates in PVA film
Authors: Song YunFei , Jiang LiLin , Wu Jie , Lu LiPing
Published: March 2024

The aggregated properties of Chlorophyll a (Chla) in polymer play a pivotal role in light capture and transfer as photostable pigment sensitizers of solar power systems. Here, we embedded the natural Chla molecules (2 × 10−3 M) extracted from spinach leaves into polyvinyl alcohol (PVA) films by casting method under different temperature. UV–VIS, fluorescence, Circular Dichroism (CD) spectroscopy, and Transmission Electron Microscopy (SEM) have been applied to investigate the optical properties and aggregated structures in detail. The excited state dynamics of these aggregates in PVA were explored using Time-Correlated Single Photon Counting (TCSPC). The de-composited components from absorption, emission, TCSPC and the CD shapes in the study show the analogous characteristics to the photosystem of cyanobacteria in some papers that features a coexisting of several aggregates (dimer, oligomer, bulk oligomer), in which the proportion of bulk oligomer can be greatly promoted under lower temperature (0 °C) due to the involvement of a large amount of water. The analysis of spectral and dynamical components reveals the bulk oligomer model of Chla in PVA, which is constructed from several oligomers by PVA chain and water. Besides, a specific red trapping center within bulk oligomer is proposed to perform capturing energy in 18 ps, which is located on the lowest end of energy flow and devotes large than 99% florescence in TCSPC.
Thermogravimetric and temperature-dependent electrical investigations of Pr3+ doped multi-component silicate glasses for microelectronic technology
Authors: J Gracie P , J Yasmin , D Geetha
Published: March 2024

Multi-component silicate glasses doped with 0, 0.5, 1, and 1.5 mol% of praseodymium (Pr3+) were synthesized by the sol–gel method. Thermal analysis of the glasses, evinced a high working temperature of 351 °C and Hruby coefficient, K

H
= 1.415 in the highly doped system, corroborating the effective role of Pr3+ ions in endowing superior thermal stability to the glass. Broadband dielectric spectroscopy was applied to study the temperature-dependent electrical behavior of the glasses for their suitability as electrodes and solid electrolyte materials in batteries. A high dielectric constant of 4797 was evidenced at 1 kHz when recorded at 473 K. The AC conductivity of the glass doped with 1 mol% was observed to be the highest with 94.8 × 10−5 S cm−1 at 10 MHz and 473 K. Jonscher’s power law exponent decreased with temperature, attributing the conducting mechanism to the Correlated Barrier Hopping (CBH) model. The Nyquist impedance spectra demonstrated a depressed semicircle with a spur at the low-frequency end, validating the non-Debye relaxation in the glasses. The equivalent circuitry of the plot predicted parallel combinations of resistor and constant phase elements which reflects a Warburg diffusion and capacitive approach. Bode’s phasor diagram confirmed the capacitive nature by a phase angle of −90° in all the glasses. While a uniform increase in dielectric constant and conductivity was observed up to 1 mol% of Pr3+, a sharp decline in the electrical phenomenon was observed with 1.5 mol% of Pr3+, due to the possible blockade of the hopping of charge carriers by the largely quantified dopant ions. Extracting a high dielectric constant, and ionic conductivity at high frequencies, with an optimal dopant concentration of 1 mol% Pr3+, the composite glasses could be considered for their potential use in integrated microcomponent storage devices as cathode and solid electrolyte materials.
Nuclear charge radius predictions based on eXtreme Gradient Boosting
Authors: Li Weifeng , Zhang Xiaoyan , Fang Jiyu
Published: March 2024

Nuclear charge radii with 8 ≤ Z ≤ 100 are studied based on the eXtreme Gradient Boosting (XGBoost) method. Besides the proton, neutron, and mass numbers, the physical quantities related to the isospin, shell, and pairing effects are important to improve the performance of the XGBoost method by including them as the input variables. The XGBoost method describes the nuclear charge radii better than the Skyrme-Hartree–Fock-Bogoliubov (HFB)-21 model, especially for odd-Z nuclei. The root-mean-square deviation with respect to the experimental data is reduced from 0.025 fm of the HFB-21 model to 0.012 fm of the XGBoost method in the learning set. It is found that the XGBoost method has reliable extrapolation ability at least for the nuclei not far from the learning region, which is verified by comparison with the data in the newly measured experimental data. When extrapolated to the unknown region, the XGBoost predictions of charge radii are close to the HFB-21 results, and the deviations between them are generally less than 0.1 fm even within about 20 steps from the known region.
From Swiss-cheese to discrete ferroelectric composites: assessing the ferroelectric butterfly shape in polarization loops
Authors: Myroshnychenko Viktor , Mulavarickal Jose Pious Mathews , Farheen Henna , Ejaz Shafaq , Brosseau Christian , Förstner Jens
Published: March 2024

We explore the polarization hysteretic behaviour and field-dependent permittivity of ferroelectric-dielectric 2D materials formed by random dispersions of low permittivity inclusions in a ferroelectric matrix, using finite element simulations. We show how the degree of impenetrability of dielectric inclusions plays a substantial role in controlling the coercive field, remnant and saturation polarizations of the homogenized materials. The results highlight the significance of the degree of impenetrability of inclusion in tuning the effective polarization properties of such ferroelectric composites: coercive field drops significantly as percolation threshold is attained and remnant polarization decreases faster than a linear decay.
Fano resonance-enhanced planar waveguide sensor utilizing MoS2 for high-performance sensing application
Authors: Maurya Rajiv , Mishra Ankit , Yadav Chandan Singh , Upadhyay Abhishek , Singh Vivek
Published: March 2024

Sensing performance of a Fano resonance waveguide based sensor having a MoS2 material assisted with low refractive index coupling prism BK7 is analyzed. Position of MoS2 is optimized by considering two six-layer structural configurations i.e. PAMCFS and PMACFS and their results are compared at particular guiding layer thickness 500 nm and coupling layer thickness 700 nm. The reflectance formula of proposed six-layer waveguide is obtained using Fresnel’s equations. Our analysis shows that the PAMCFS waveguide gives better sensing performance than PMACFS. Further, sensing parameters is analyzed for different thickness of coupling layer and guiding layer. The maximum obtained sensitivity for zero order Fano resonance mode in intensity interrogation of the proposed PAMCFS waveguide structure is 6.847 × 106 a.u.-RIU–1 at guiding layer thickness 800 nm and coupling layer thickness 1000 nm. Also, at these thicknesses, FWHM is obtained in order of ∼10−6 while the achieved detection accuracy and figure of merit in order of ∼107 and ∼106 respectively.
Divertor enrichment of recycling impurity species (He, N2, Ne, Ar, Kr) in ASDEX Upgrade H-modes
Authors: Kallenbach A. , Dux R. , Henderson S.S. , Tantos C. , Bernert M. , Day C. , McDermott R.M. , Rohde V. , Zito A. ,   the ASDEX Upgrade Team
Published: March 2024

Particle balance calculations are done for the seeding species N2, Ne, Ar, Kr as well as He with the aim of obtaining a realistic description of the divertor and core plasma impurity content. Experimental time traces of main plasma impurity densities are fitted by a single, time-independent parameter v

z
,
in

eff

. This parameter represents the product of the impurity inward pinch in the pedestal, used for the description of gross fueling here, and the enrichment factor between the sub-divertor gas reservoir and the upstream separatrix. v

z
,
in

eff

depends strongly on the first ionization energy as well as on the charge Z or mass of the impurity. The prevailing dependence of the enrichment values on the ionization energy suggests the importance of the relative impurity and deuterium ionization lengths in the divertor. Regression analysis of v

z
,
in

eff

yields an expression for the impurity concentrations in the core and the divertor of ASDEX Upgrade which allows the prediction of the corresponding impurity densities and their divertor enrichment within a factor of 2 with only engineering parameters as input. A simple wall model has been introduced to take into account wall storage and release of impurities, e.g. for conditions of pre-loaded walls due to seeding in previous discharges. Wall effects are observed for all species considered, but wall storage turns out to be more important for N and He compared to Ne, Ar, Kr. Similar enrichment values are obtained for ELMy H-modes and EDA/QCE no-ELM regimes. A factor of approximately 1.4 reduction in enrichment is observed for divertor conditions for pronounced detachment with Ar and N2. The obtained analytical model for the core and sub-divertor impurity densities is well suited for integration into a discharge flight simulator or a real time state observer.
Bioinspiration from bats and new paradigms for autonomy in natural environments
Authors: Müller Rolf
Published: March 2024

Achieving autonomous operation in complex natural environment remains an unsolved challenge. Conventional engineering approaches to this problem have focused on collecting large amounts of sensory data that are used to create detailed digital models of the environment. However, this only postpones solving the challenge of identifying the relevant sensory information and linking it to action control to the domain of the digital world model. Furthermore, it imposes high demands in terms of computing power and introduces large processing latencies that hamper autonomous real-time performance. Certain species of bats that are able to navigate and hunt their prey in dense vegetation could be a biological model system for an alternative approach to addressing the fundamental issues associated with autonomy in complex natural environments. Bats navigating in dense vegetation rely on clutter echoes, i.e. signals that consist of unresolved contributions from many scatters. Yet, the animals are able to extract the relevant information from these input signals with brains that are often less than 1 g in mass. Pilot results indicate that information relevant to location identification and passageway finding can be directly obtained from clutter echoes, opening up the possibility that the bats’ skill can be replicated in man-made autonomous systems.
A scalable crop yield estimation framework based on remote sensing of solar-induced chlorophyll fluorescence (SIF)
Authors: Kira Oz , Wen Jiaming , Han Jimei , McDonald Andrew J , Barrett Christopher B , Ortiz-Bobea Ariel , Liu Yanyan , You Liangzhi , Mueller Nathaniel D , Sun Ying
Published: March 2024

Projected increases in food demand driven by population growth coupled with heightened agricultural vulnerability to climate change jointly pose severe threats to global food security in the coming decades, especially for developing nations. By providing real-time and low-cost observations, satellite remote sensing has been widely employed to estimate crop yield across various scales. Most such efforts are based on statistical approaches that require large amounts of ground measurements for model training/calibration, which may be challenging to obtain on a large scale in developing countries that are most food-insecure and climate-vulnerable. In this paper, we develop a generalizable framework that is mechanism-guided and practically parsimonious for crop yield estimation. We then apply this framework to estimate crop yield for two crops (corn and wheat) in two contrasting regions, the US Corn Belt US-CB, and India’s Indo–Gangetic plain Wheat Belt IGP-WB, respectively. This framework is based on the mechanistic light reactions (MLR) model utilizing remotely sensed solar-induced chlorophyll fluorescence (SIF) as a major input. We compared the performance of MLR to two commonly used machine learning (ML) algorithms: artificial neural network and random forest. We found that MLR-SIF has comparable performance to ML algorithms in US-CB, where abundant and high-quality ground measurements of crop yield are routinely available (for model calibration). In IGP-WB, MLR-SIF significantly outperforms ML algorithms. These results demonstrate the potential advantage of MLR-SIF for yield estimation in developing countries where ground truth data is limited in quantity and quality. In addition, high-resolution and crop-specific satellite SIF is crucial for accurate yield estimation. Therefore, harnessing the mechanism-guided MLR-SIF and rapidly growing satellite SIF measurements (with high resolution and crop-specificity) hold promise to enhance food security in developing countries towards more effective responses to food crises, agricultural policies, and more efficient commodity pricing.
Potential nitrogen mobilisation from the Yedoma permafrost domain
Authors: Strauss Jens , Marushchak Maija E , van Delden Lona , Sanders Tina , Biasi Christina , Voigt Carolina , Jongejans Loeka L , Treat Claire
Published: March 2024

Permafrost regions, characterised by extensive belowground excess ice, are highly vulnerable to rapid thaw, particularly in areas such as the Yedoma domain. This region is known to freeze-lock a globally significant stock of soil nitrogen (N). However, the fate of this N upon permafrost thaw remains largely unknown. In this study, we assess the impact of climate warming on the size and dynamics of the soil N pool in (sub-)Arctic ecosystems, drawing upon recently published data and literature. Our findings suggest that climate warming and increased thaw depths will result in an expansion of the reactive soil N pool due to the larger volume of (seasonally) thawed soil. Dissolved organic N emerges as the predominant N form for rapid cycling within (sub-)Arctic ecosystems. The fate of newly thawed N from permafrost is primarily influenced by plant uptake, microbial immobilisation, changes in decomposition rates due to improved N availability, as well as lateral flow. The Yedoma domain contains substantial N pools, and the partial but increasing thaw of this previously frozen N has the potential to amplify climate feedbacks through additional nitrous oxide (N2O) emissions. Our ballpark estimate indicates that the Yedoma domain may contribute approximately 6% of the global annual rate of N2O emissions from soils under natural vegetation. However, the released soil N could also mitigate climate feedbacks by promoting enhanced vegetation carbon uptake. The likelihood and rate of N2O production are highest in permafrost thaw sites with intermediate moisture content and disturbed vegetation, but accurately predicting future landscape and hydrology changes in the Yedoma domain remains challenging. Nevertheless, it is evident that the permafrost-climate feedback will be significantly influenced by the quantity and mobilisation state of this unconsidered N pool.
Degree of polarization in dissipative optical systems
Authors: Cirino M J , Brandão P A
Published: March 2024

The polarization matrix formalism is employed to analyze the polarization properties of transmitted narrowband light through several optical setups involving active and dissipative structures. It is demonstrated that the degree of polarization of the output light can increase after propagation in a active/dissipative periodic media. Furthermore, the impact of introducing optical elements like polarizers, compensators, and rotators is examined, and their collective effect on the degree of polarization is discussed.
Short excitonic lifetimes of MoSe2 monolayers grown by molecular beam epitaxy on the hexagonal boron nitride
Authors: Oreszczuk Kacper , Pacuski Wojciech , Rodek Aleksander , Raczyński Mateusz , Kazimierczuk Tomasz , Nogajewski Karol , Taniguchi Takashi , Watanabe Kenji , Potemski Marek , Kossacki Piotr
Published: March 2024

We present a time-resolved optical study of recently developed narrow-line MoSe2 monolayers grown on hexagonal boron nitride with means of molecular beam epitaxy. We find that the photoluminescence decay times are significantly shorter than in the case of the exfoliated samples, even below one picosecond. Such a short timescale requires measurements with better resolution than achievable with a streak camera. Therefore, we employ an excitation correlation spectroscopy pump-probe technique. This approach allows us to identify two distinct non-radiative recombination channels attributed to lattice imperfections. The first channel is active at helium temperatures. It reduces the lifetime of the neutral exciton to below one picosecond. The second channel becomes active at elevated temperatures, further shortening the lifetimes of both neutral and charged exciton. The high effectiveness of both radiative and non-radiative recombination makes epitaxial MoSe2 a promising material for ultrafast optoelectronics.