bluuebunny/crossref_metadata_2025 huggingface dataset:
Review of studies on enhancing thermal energy grade in the open ocean
Authors: Yang Xin , Li Zhengnong , Shen Yijun , Kuang Rao
Published: December 2022

Ocean thermal energy conversion is one of the important ways to utilize low-grade ocean thermal energy. The main reasons for its low economic feasibility include high cost, small temperature difference, low energy efficiency, and high consumption of deep-sea cold energy extraction pumps. Some new means to improve the thermal energy grade may be beneficial to improve the economic feasibility of ocean thermal energy conversion, desalination, and other systems. The research progress and analysis results of ways to obtain low-grade thermal energy in the ocean surface by using solar energy, offshore platform waste heat, compressed air storage waste heat, and other methods show that (1) after using solar energy or waste heat to raise sea water temperature, shallow seawater can be used as the cold source, which can reduce most of the pump consumption and expensive riser cost of lifting cold seawater. This way improves the net power generation efficiency more significantly than improving the circulation mode and working medium and also significantly improves the economic feasibility. (2) Exhaust waste heat from offshore platform diesel power generation and compressed air energy storage power generation systems can be used to obtain a larger temperature difference between cold and hot seawater and further improve the efficiency of thermal power generation. (3) The low density of solar energy flow at the sea level leads to the high cost of offshore platforms. Incorporating ocean thermal energy conversion systems into floating photovoltaic power generation, seawater desalination and other systems can reduce the cost of offshore platforms.
Plasma kernel model and energy transformation characteristic of plasma synthetic jet actuator
Authors: Chen Xiuxiu , Sun Zhengzhong
Published: December 2022

This article conducted a theoretical, experimental, and numerical investigation to clarify the plasma kernel model and energy transformation characteristics of the plasma synthetic jet actuator (PSJA). Plasma kernel and blast wave theory were used to describe the formation and evolution of the arc-discharge energy deposition process and build a plasma kernel model. Schlieren experiment visualized the formation and evolution of the synthetic jet flow and used it as a validation of the numerical simulation. Five plasma synthetic jet actuators with different cavity volumes (128–512 mm3) and different discharge energy (2.8–11.3 mJ) were modeled numerically to investigate the energy transformation characteristic of PSJA. Results showed that plasma kernel radius and formation time could be theoretically predicted with specific deposition energy and correspond well with simulation results. The peak pressure and temperature rise in the cavity can also be calculated. Moreover, the proportion of kinetic energy increases linearly with non-dimensional deposition energy, while potential energy has a reverse tendency with non-dimensional cavity volume and deposition energy.
A study of pulsating behavior and stability parameter for one-dimensional non-ideal detonations
Authors: Xu Zhuo , Dong Gang , Wang Yang
Published: December 2022

One-dimensional numerical simulations of non-ideal detonations were performed by using inviscid reactive Euler equations. Chemical reactions in the equations were described by two-step consecutive irreversible reactions A → B → C, which include an exothermic step (A → B) followed by an endothermic step (B → C). Non-ideal detonations are achieved when endothermicity exists in the system. The periodic oscillation behavior of peak pressure during the propagation of a one-dimensional detonation wave was studied with the different exothermicity/endothermicity and different degrees of overdrive. The results show that the increase in exothermicity, the reduction in endothermicity, and the enhanced degrees of overdrive can stabilize the propagation of detonation waves. The influence of the exothermic reaction plays a dominant role for the stability of the one-dimensional non-ideal detonations, which is further confirmed by a theoretical analysis. In addition, the stability parameter χ, proposed originally by Radulescu “The propagation and failure mechanism of gaseous detonations: experiments in porous-walled tubes,” Ph.D. thesis (McGill University, Montreal, Canada, (2003), was extended to predict the stability of non-ideal detonations, based on the Zel'dovich–Neumann–Döring structure of the non-ideal detonations. The results show that the extended stability parameter can well match the stability boundary for all of cases in the present study.
Active glassy dynamics is unaffected by the microscopic details of self-propulsion
Authors: Debets Vincent E. , Janssen Liesbeth M. C.
Published: December 2022

Recent years have seen a rapid increase of interest in dense active materials, which, in the disordered state, share striking similarities with the conventional passive glass-forming matter. For such passive glassy materials, it is well established (at least in three dimensions) that the details of the microscopic dynamics, e.g., Newtonian or Brownian, do not influence the long-time glassy behavior. Here, we investigate whether this still holds true in the non-equilibrium active case by considering two simple and widely used active particle models, i.e., active Ornstein-Uhlenbeck particles (AOUPs) and active Brownian particles (ABPs). In particular, we seek to gain more insight into the role of the self-propulsion mechanism on the glassy dynamics by deriving a mode-coupling theory (MCT) for thermal AOUPs, which can be directly compared to a recently developed MCT for ABPs. Both theories explicitly take into account the active degrees of freedom. We solve the AOUP- and ABP-MCT equations in two dimensions and demonstrate that both models give almost identical results for the intermediate scattering function over a large variety of control parameters (packing fractions, active speeds, and persistence times). We also confirm this theoretical equivalence between the different self-propulsion mechanisms numerically via simulations of a polydisperse mixture of active quasi-hard spheres, thereby establishing that, at least for these model systems, the microscopic details of self-propulsion do not alter the active glassy behavior.
Hybrid method for wall local refinement in lattice Boltzmann method simulation
Authors: Lyu Changhao , Liu Peiqing , Hu Tianxiang , Geng Xin , Qu Qiuling , Sun Tao , Akkermans Rinie A. D.
Published: December 2022

The recent development of the lattice Boltzmann method enables its widespread application in various industrial areas. However, in the simulation of complicated industrial problems, considerable grid numbers are required to achieve reasonable resolution in the near-wall region due to the lack of a local refinement method on the geometry. This study proposes a new hybrid grid refinement method, which comprises the reconstruction algorithm in refined near-wall nodes on the refinement interface and the in-domain interpolation multi-grid method to prevent the local distortion of the pseudo-wall among resolution levels. The proposed method is validated on a two-dimensional flat plate and NACA0012 airfoil at low and high Reynolds numbers. Furthermore, the aerodynamic and aeroacoustics of a pair of counter-rotating propellers are simulated with the proposed lattice Boltzmann method and compared with the results obtained using commercial software.
Realizability of iso-g2 processes via effective pair interactions
Authors: Wang Haina , Stillinger Frank H. , Torquato Salvatore
Published: December 2022

An outstanding problem in statistical mechanics is the determination of whether prescribed functional forms of the pair correlation function g2(r) [or equivalently, structure factor S(k)] at some number density ρ can be achieved by many-body systems in d-dimensional Euclidean space. The Zhang–Torquato conjecture states that any realizable set of pair statistics, whether from a nonequilibrium or equilibrium system, can be achieved by equilibrium systems involving up to two-body interactions. To further test this conjecture, we study the realizability problem of the nonequilibrium iso-g2 process, i.e., the determination of density-dependent effective potentials that yield equilibrium states in which g2 remains invariant for a positive range of densities. Using a precise inverse algorithm that determines effective potentials that match hypothesized functional forms of g2(r) for all r and S(k) for all k, we show that the unit-step function g2, which is the zero-density limit of the hard-sphere potential, is remarkably realizable up to the packing fraction ϕ = 0.49 for d = 1. For d = 2 and 3, it is realizable up to the maximum “terminal” packing fraction ϕc = 1/2d, at which the systems are hyperuniform, implying that the explicitly known necessary conditions for realizability are sufficient up through ϕc. For ϕ near but below ϕc, the large-r behaviors of the effective potentials are given exactly by the functional forms exp[ − κ(ϕ)r] for d = 1, r−1/2 exp[ − κ(ϕ)r] for d = 2, and r−1 exp[ − κ(ϕ)r] (Yukawa form) for d = 3, where κ−1(ϕ) is a screening length, and for ϕ = ϕc, the potentials at large r are given by the pure Coulomb forms in the respective dimensions as predicted by Torquato and Stillinger [Phys. Rev. E 68, 041113 (2003)]. We also find that the effective potential for the pair statistics of the 3D “ghost” random sequential addition at the maximum packing fraction ϕc = 1/8 is much shorter ranged than that for the 3D unit-step function g2 at ϕc; thus, it does not constrain the realizability of the unit-step function g2. Our inverse methodology yields effective potentials for realizable targets, and, as expected, it does not reach convergence for a target that is known to be non-realizable, despite the fact that it satisfies all known explicit necessary conditions. Our findings demonstrate that exploring the iso-g2 process via our inverse methodology is an effective and robust means to tackle the realizability problem and is expected to facilitate the design of novel nanoparticle systems with density-dependent effective potentials, including exotic hyperuniform states of matter.
From vertices to vortices in magnetic nanoislands
Authors: Saccone Michael , Gartside Jack C. , Stenning Kilian D. , Branford Will R. , Caravelli Francesco
Published: December 2022

Recent studies in magnetic nanoarrays show that a variety of complex magnetic states and textures emerge as a function of a single magnetic nanoisland's aspect ratio. We propose a model that, in addition to fitting experiments, predicts magnetic states with continuous symmetry at particular aspect ratios and reveals a duality between vortex and vertex states. Our model opens new means of engineering novel types of artificial spin systems, and their application to complex magnetic textures in devices and computing.
Band parameters of group III–V semiconductors in wurtzite structure
Authors: Ziembicki Jakub , Scharoch Paweł , Polak Maciej P. , Wiśniewski Michał , Kudrawiec Robert
Published: December 2022

The properties of most III–V semiconductor materials in the wurtzite structure are not known because of their metastable character. However, recent advances in the growth of III–V wurtzite nanorods open new perspectives for applications. In this work, we present a systematic computational study of bulk wurtzite III–V semiconductors, using predictive ab initio methods, to provide a necessary base knowledge for studying the nanostructures. The most important physical properties of bulk systems, i.e., lattice constants, elasticity, spontaneous polarization, piezoelectricity, band structures, deformation potentials, and band offsets, have been studied. Comparison with the available experimental and theoretical data shows the high credibility of our results. Moreover, we provide a complete set of parameters for a six-band k⋅p model, which is widely used for simulating devices based on semiconductor heterostructures.
The financial implications of investigating false-positive and true-positive mammograms in a national breast cancer screening program
Authors: Soon Jason , Houssami Nehmat , Clemson Michelle , Lockie Darren , Farber Rachel , Barratt Alexandra , Elshaug Adam , Howard Kirsten
Published: December 2022

Objectives To determine the total annual screening and further-investigation costs of investigating false-positive and true-positive mammograms in the Australian population breast-screening program. Methods This economic analysis used aggregate-level retrospective cohort data of women screened at a breast-screening clinic. Counts and frequencies of each diagnostic workup-sequence recorded were scaled up to national figures and costed by estimating per-patient costs of procedures using screening clinic cost data. Main outcomes and measures estimated were percentage share of total annual screening and further-investigation costs for the Australian population breast-screening program of investigating false-positive and true-positive mammograms. Secondary outcomes determined were average costs of investigating each false-positive and true-positive mammogram. Sensitivity analyses involved recalculating results excluding subgroups of patients below and above the screening age range of 50–74 years. Results Of 8235 patients, the median age was 60.35 years with interquartile range of 54.17–67.17 years. A total of 15.4% (ranging from 13.4 to 15.4% under different scenarios) of total annual screening and further-investigation costs were from investigating false-positive mammograms. This exceeded the share of costs from investigating true-positives (13%). Conclusions We have developed a transparent and non-onerous approach for estimating the costs of false-positive and true-positive mammograms associated with the national breast-screening program. While determining an optimal balance between false-positives and true-positive rates must rely primarily on health outcomes, costs are an important consideration. We recommend that future research adopts and refines similar approaches to facilitate better monitoring of these costs, benchmark against estimates from other screening programs, and support optimal policy development.
Linguistic picture of woman in French and Serbian
Authors: Marčeta Jovana
Published: December 2022

This study examines the similarities and differences regarding the perception of woman between university students
in France and Serbia. The method of discrete free associations was used to reconstruct and compare models of the linguistic
picture of woman in the two language communities in order to explore the extent to which these pictures reflect properties
observed across languages (i.e., universal) and the extent to which they are language specific. The results show that the
relationship between the primary response and the stimulus in French is antonymous (woman-man), whereas the
primary response given by Serbian students indicates the stability of the concept of mother in the Serbian
language and culture. Nevertheless, the conceptual classification of the responses suggests that the linguistic picture of woman
in French and Serbian expresses shared stereotypic beliefs about women.
Anti-Muslim semantic framing by politicians, Facebook groups, and violent extremists
Authors: Sullivan Karen
Published: December 2022

Recent studies have shown that semantic framing can reveal bias and racism. The current study introduces a novel method for locating frames in texts, and employs this method to find frames for Muslims, Europeans and Australians in a range of texts by anti-Muslim and non-anti-Muslim authors. The study finds that several derogatory frames previously associated with racism are applied to Muslims in the anti-Muslim texts, supporting studies showing that anti-Muslim bias resembles other forms of racism. Moreover, different frames are preferred by more and less extreme anti-Muslim authors, with certain frames predominating in the manifestos of white supremacist gunmen. These frames may be a warning sign that frame users are potentially prone to violence.
Forage seed system performance of Ethiopia: An overview based on key indicators
Authors: Kalsa Karta Kaske , Dey Bhramar
Published: December 2022

An increase in improved forages to serve as high-quality animal feed around the year is a necessity in countries with large livestock populations. However, for increased production of improved forages, a viable and sustainable forage seed system needs to be functional. In Ethiopia, an inadequate supply of forage seed has been identified as one of the major constraints to increased forage production. To assess the current state of the forage seed system, as well as, to monitor its growth in the future, the present study provides a framework that captures important information related to the forage seed system performance in Ethiopia. Data on key indicators along the forage seed value chain (such as variety development and release, early generation seed availability, commercial seed production, forage seed promotion and marketing, and seed quality assurance) were collected using a structured survey instrument. Results indicate a considerable number of forage varieties are already registered in the country through the national agricultural research system. However, a limited quantity of early generation seed is being delivered to seed producers. On the other hand, the involvement of commercial seed producers in the forage sector is limited. There are weak forage seed promotion and quality assurance mechanisms because most of the attention in the extension and regulatory structures is provided to the food crops. The study provides a template to monitor forage seed system performance in a developing country and identifies opportunities and recommendations for development partners, practitioners, national stakeholders, and decision-makers active in the Ethiopian forage sector.
Microstructure evolution of adiabatic shear band in AZ31 alloy under dynamic compression
Authors: Liu Xuanyu , Mao Pingli , Wu Xiaoxu , Zhou Le , Wang Zhi , Wang Feng , Liu Zheng
Published: December 2022

The formation of adiabatic shear band (ASB) and its damage behaviour in AZ31 alloy under high strain rate compression (2000 s−1) were investigated in this study by using a split Hopkinson pressure bar. Microstructure of the ASB was characterised by electron back-scattering diffraction and transmission electron microscopy, and the adiabatic shear damage behaviour was analysed through finite element simulation by LS-DYNA. The results show that the ASB and the surrounding microstructure form a gradient microstructure distribution, and the formation of ultra-fine grains in the ASB is due to rotational dynamic recrystallisation. The combination of work hardening and grain refinement in ASB leads to a high microhardness. Micro-voids grow in the ASB and eventually form macro-cracks, leading to material failure.
Fretting wear behaviour of ultrafine-grained copper produced by cryogenic temperature extrusion machining
Authors: Zhang Baoyu , Zeng Yuning , Pang Xueqin , Deng Wenjun
Published: December 2022

Cryogenic temperature extrusion machining (CT-EM), as a new process, was first applied for preparing ultrafine-grained (UFG) copper strips. The microstructure evolution and mechanical properties (hardness and fretting wear) were characterised by electron backscatter diffraction and transmission electron microscopy methods. Refined grains (450 nm) and high dislocation density could be obtained by CT-EM because of effectively suppressing heat generation and the annihilation of dislocations. As a result, the CT-EM sample exhibited enhanced fretting wear properties, e.g. a much lower friction coefficient (reducing 0.1–0.2) and a lower wear loss (decreasing 32–45%) were achieved due to its enhanced hardness and refined microstructure. In-depth, the delamination and oxidation wear proved to be the primary wear mechanism of the CT-EM sample under dry wear conditions.
Coherent interaction of multistate quantum systems possessing the Wigner–Majorana and Morris–Shore dynamic symmetries with pulse trains
Authors: Stanchev Stancho G , Vitanov Nikolay V
Published: December 2022

We present exact analytic formulae which describe the interaction of multistate quantum systems possessing the Wigner–Majorana and Morris–Shore dynamic symmetries with a train of pulses. The pulse train field can be viewed as repeated interactions of the quantum system with the same field and hence the overall propagator is expressed as the matrix power of the single-pulse propagator. Because of the symmetries the multistate dynamics is characterized by intrinsic two-state features, described by one or more pairs of complex-valued Cayley–Klein parameters. This facilitates the derivation of explicit formulae linking the single-step and multi-step propagators. The availability of such analytic relations opens the prospects for a variety of applications with ensembles of qubits, qutrits and generally qudits, e.g. analytic description of coherent pulse-train interactions, coherent amplification of quantum gate errors for accurate quantum gate tomography, dynamical rephasing of inhomogeneously broadened ensembles, quantum sensing of small electric or magnetic fields, etc.
Phonon Raman spectroscopy of nanocrystalline multinary chalcogenides as a probe of complex lattice structures
Authors: Dzhagan Volodymyr , Litvinchuk Alexander P , Valakh Mykhailo Ya , Zahn Dietrich R T
Published: December 2022

Ternary (I–III–VI) and quaternary (I–II–IV–VI) metal-chalcogenides like CuInS2 or Cu2ZnSn(S,Se)4 are among the materials currently most intensively investigated for various applications in the area of alternative energy conversion and light-emitting devices. They promise more sustainable and affordable solutions to numerous applications, compared to more developed and well understood II–VI and III–V semiconductors. Potentially superior properties are based on an unprecedented tolerance of these compounds to non-stoichiometric compositions and polymorphism. However, if not properly controlled, these merits lead to undesirable coexistence of different compounds in a single polycrystalline lattice and huge concentrations of point defects, becoming an immense hurdle on the way toward real-life applications. Raman spectroscopy of phonons has become one of the most powerful tools of structural diagnostics and probing physical properties of bulk and microcrystalline I–III–VI and I–II–IV–VI compounds. The recent explosive growth of the number of reports on fabrication and characterization of nanostructures of these compounds must be pointed out as well as the steady use of Raman spectroscopy for their characterization. Interpretation of the vibrational spectra of these compound nanocrystals (NCs) and conclusions about their structure can be complicated compared to bulk counterparts because of size and surface effects as well as emergence of new structural polymorphs that are not realizable in the bulk. This review attempts to summarize the present knowledge in the field of I–III–VI and I–II–IV–VI NCs regarding their phonon spectra and capabilities of Raman and IR spectroscopies in the structural characterizations of these promising families of compounds.
Effect of principal environmental parameters on performance of LFMCW photonic radar during transmission
Authors: Chen Shilin , Pu Tao , Wang Li , Chen Kai , Liu Menghan , Zheng Jilin
Published: December 2022

Noncoherent and coherent systems of linear frequency modulated continuous wave photonic radar under normal environmental conditions are constructed by co-simulation. In particular, the simulation models of different atmospheric humidity conditions are constructed to analyze the quantitative relationship between the system’s ability to detect targets and humidity. It is discussed the relationship between detection distance and channel parameters under the premise of reasonable signal-to-noise ratio (SNR). In particular, the SNR of the noncoherent photonic radar is reduced to less than 10 dB when relative humidity >40%, which the laser power is 8 dBm and the detection distance is 100 m. However, the coherent photonic radar has a good performance of more than 21.7 dB. The results show that the noncoherent system is more susceptible to atmospheric humidity than the coherent system, and the heterodyne detection coherent system can achieve longer detection distance and better weak echo signal detection capability.
Topological shadowing methods in arnold diffusion: weak torsion and multiple time scales
Authors: Clarke Andrew , Fejoz Jacques , Guàrdia Marcel
Published: December 2022

Consider a map which possesses a normally hyperbolic invariant manifold of any even dimension with transverse homoclinic channels. We develop a topological shadowing argument to prove the existence of Arnold diffusion along the invariant manifold, shadowing some iterations of the inner dynamics carried by the invariant manifold and the outer dynamics induced by the stable and unstable foliations. In doing so, we generalise an idea of Gidea and de la Llave (2006 Discrete Contin. Dyn. Syst.
14 295), based on the method of correctly aligned windows and a so-called transversality-torsion argument. Our proof permits that the dynamics on the invariant manifold satisfy only a non-uniform twist condition, and, most importantly for applications, that the splitting of separatrices be small in certain directions and thus the associated drift in actions very slow; diffusion occurs in the directions of the manifold having non-small splitting. Furthermore we provide estimates for the diffusion time.
Positive Lyapunov exponent for some Schrödinger cocycles over multidimensional strongly expanding torus endomorphisms
Authors: Zhang Guanzhen , Li Xiong
Published: December 2022

In the paper we are concerned with the discrete Schrödinger cocycle over two kinds of expanding endomorphisms ond-dimensional torus with a large class of potentials and a big coupling constantλ, and will prove that the Lyapunov exponentL(E)>logλ8−log54for all energiesE.
A dynamic learning-based ECG feature extraction method for myocardial infarction detection
Authors: Sun Qinghua , Xu Zhanfei , Liang Chunmiao , Zhang Fukai , Li Jiali , Liu Rugang , Chen Tianrui , Ji Bing , Chen Yuguo , Wang Cong
Published: December 2022

Objective. Myocardial infarction (MI) is one of the leading causes of human mortality in all cardiovascular diseases globally. Currently, the 12-lead electrocardiogram (ECG) is widely used as a first-line diagnostic tool for MI. However, visual inspection of pathological ECG variations induced by MI remains a great challenge for cardiologists, since pathological changes are usually complex and slight. Approach. To have an accuracy of the MI detection, the prominent features extracted from in-depth mining of ECG signals need to be explored. In this study, a dynamic learning algorithm is applied to discover prominent features for identifying MI patients via mining the hidden inherent dynamics in ECG signals. Firstly, the distinctive dynamic features extracted from the multi-scale decomposition of dynamic modeling of the ECG signals effectively and comprehensibly represent the pathological ECG changes. Secondly, a few most important dynamic features are filtered through a hybrid feature selection algorithm based on filter and wrapper to form a representative reduced feature set. Finally, different classifiers based on the reduced feature set are trained and tested on the public PTB dataset and an independent clinical data set. Main results. Our proposed method achieves a significant improvement in detecting MI patients under the inter-patient paradigm, with an accuracy of 94.75%, sensitivity of 94.18%, and specificity of 96.33% on the PTB dataset. Furthermore, classifiers trained on PTB are verified on the test data set collected from 200 patients, yielding a maximum accuracy of 84.96%, sensitivity of 85.04%, and specificity of 84.80%. Significance. The experimental results demonstrate that our method performs distinctive dynamic feature extraction and may be used as an effective auxiliary tool to diagnose MI patients.
Age-dependent cardiorespiratory directional coupling in wake-resting state
Authors: Yoon Heenam
Published: December 2022

Objective. Cooperation in the cardiorespiratory system helps maintain internal stability. Various types of system interactions have been investigated; however, the characteristics of the interactions have mostly been studied using data collected in well-defined physiological states, such as sleep. Furthermore, most analyses provided general information about the interaction, making it difficult to quantify how the systems influenced one another. Approach. Cardiorespiratory directional coupling was investigated in different age groups (20 young and 19 elderly subjects) in a wake-resting state. The directionality index (DI) was calculated using instantaneous phases from the heartbeat interval and respiratory signal to provide information about the strength and direction of interaction between the systems. Statistical analysis was performed between the groups on the DI and independent measures of directionality (ncr: influence from cardiac system to respiratory system, and ncc: influence from the respiratory system to the cardiac system). Main results. The values of DI were −0.52 and −0.17 in the young and elderly groups, respectively (p < 0.001). Furthermore, the values of ncr and ncc were found to be significantly different between the groups (p < 0.001), respectively. Significance. Changes in both directions between the systems influence different aspects of cardiorespiratory coupling between the groups. This observation could be linked to different levels of autonomic modulation associated with ageing. Our approach could aid in quantitatively tracking and comprehending how systems interact in response to physiological and environmental changes. It could also be used to understand how abnormal interaction characteristics influence physiological system dysfunctions and disorders.
Spectral transition of multiscale turbulence in the tokamak pedestal
Authors: Belli E A , Candy J , Sfiligoi I
Published: December 2022

The transition in the turbulence spectrum from ion-scale dominated regimes to multiscale transport regimes that couple ion and electron scales is studied with gyrokinetic simulations of turbulent transport. The simulations are based on DIII-D high-confinement mode (H-mode) plasma parameters in the tokamak pedestal. The transition is initiated by varying the ion temperature gradient. To our knowledge, no full multiscale simulations of pedestal-like transport have been done previously. The experimental parameters lie in a bifurcation region between the two regimes. At long wavelengths, a complex, ion-direction hybrid mode is the dominant linearly unstable drift wave, while an electron temperature gradient-driven mode is unstable at short wavelengths. In the transition from the multiscale branch to the ion-scale branch, the magnitude of the ion-scale poloidal wavenumber spectrum of the nonlinear turbulent energy flux increases and the magnitude of the high-wavenumber spectrum decreases. The decrease in the electron-scale transport is due to nonlinear mixing with ion-scale fluctuations and the ion-scale-driven zonal flows. A shift in the total energy associated with the fluctuating electrostatic potential intensity from dominantly drift kinetic energy in the multiscale regime to dominantly potential intensity in the ion-scale regime is well-correlated with the trend in the total energy flux.
Accurate analytical models of hot carrier degradation in nMOSFET and nFinFET considering saturation effect
Authors: Li Zheng-Kang , Wu Zhao-Hui , Zhang Xiao-Wen , Li Bin , Lin Xiao-Ling
Published: December 2022

In this paper, models of hot carrier degradation (HCD) in nMOSFET and nFinFET, combined with the physical mechanism and reaction-diffusion framework and considering saturation effect, are proposed. The HCD data of different technology nodes of nMOSFET and nFinFET are used to verify the accuracy of the models. The results show that the prediction errors of device parameter degradation under different stress voltages are less than 10% for several types of short channel devices, which is better than the existing reported research results. Furthermore, the models have simple analytical expressions that allow them to not only be applied to device HCD prediction, but also be extended to circuit level HCD prediction tool more easily.
Sensitivity of the thermomagnetic instability in superconducting film to magnetic perturbation for electromagnetic interference detection
Authors: Jiang Lu , Xue Cun , Zhou You-He
Published: December 2022

The time-varying magnetic field with electromagnetic perturbation is regarded as an important parameter for the thermomagnetic stability of superconducting film devices. In this work, using a thermomagnetic model, we investigate the sensitivity of thermomagnetic instability in superconducting films exposed to a linear ramp magnetic field, superposed by the additional AC magnetic perturbation with tunable amplitude and oscillation frequency. Surprisingly, we find that the thermomagnetic instability is a non-monotonic function with the increasing oscillation frequency of the magnetic perturbation, depending on the working temperature and oscillation amplitude. The unexpected non-monotonic sensitivity of the thermomagnetic instability is revealed by the characteristic oscillation of the electric field, which cannot be aggravated by the AC magnetic perturbation at very high frequencies. The findings of this paper demonstrate that the magnetic perturbation at very low or high frequencies is not the main factor that triggers the thermomagnetic instability of superconducting films. Furthermore, using the magnetic moment measurement, we propose possible electromagnetic interference detection by the superconducting film based on such non-monotonic sensitivity of the thermomagnetic instability, which can be used to detect the tunable target electromagnetic interference with characteristic frequency in a complex electromagnetic environment.
High-efficiency broadband perfect absorber based on a multilayered pyramid structure
Authors: Meng Qiqi , Zheng Ling , Chen Fang , Zhang Huafeng , Yang Wenxing
Published: December 2022

In this paper, an ultra-broadband perfect absorber based on a four-layer pyramid metamaterial and a metal insulator metal (MIM) structure has been demonstrated and investigated. Finite-difference time-domain (FDTD) results indicate that the absorption originates from localized surface plasmons and waveguide mode resonance effect. An average absorption of 96.18 % with bandwidth ranging from 308 nm to 2387 nm was achieved, and the average absorption in the entire wave band (200–2800 nm) was approximately 94.64%. The results of the impedance matching theory are consistent with the FDTD simulation. Polarization insensitivity was investigated by studying the absorption characteristic of TE and TM polarizations. The effect of top and bottom materials was investigated and compared in detail. Moreover, by adjusting the geometrical size, the absorption performance can be fine- tuned. In addition, the proposed broadband absorber exhibited excellent absorption stability and environmental refractive index tolerance. Without noble metal materials, the proposed structure can reduce the fabrication costs. We believe that the proposed broadband absorber has potential applications in solar cells, infrared imaging, and thermal emitters.
Nonlinear electron-acoustic structures in two-temperature relativistic degenerate plasmas
Authors: Ali Sanawar , Ali S , Naeem Ismat , Al-Hadeethi Yas
Published: December 2022

Fully nonlinear electron-acoustic (EA) structures are studied in the presence of relativistic degeneracy pressure attributing to electron species in a degenerate plasma. The plasma is taken as a collisionless and unmagnetized, containing mobile cool electrons, inertialess hot electrons and static ions. The fluid equations for such a plasma are incorporated and solved together by using the charge-neutrality hypothesis and diagonalization matrix technique obtaining the characteristic wave equations in the form of inviscid Burgers’ equations. Negative solitary structures are found in the form of potential profiles, which can be developed into nonstationary shocklets, greatly affected by the weak and strong relativistic degenerate densities. The structures are not only modified by the temporal evolution but also by thermal correction parameter. Moreover, the application of Taylor expansion to the eigenvalue may lead to the derivation of nonlinear phase and shock speeds, depending significantly on the electrostatic potential and other plasma parameters. The present findings are important to understand solitary and shocklet structures in dense plasmas, where both cool and hot electrons are regarded as the relativistic and degenerate species.
Bio-fabrication of Ni doped ZnO nanoparticles using Annona Muricata leaf extract and investigations of their antimicrobial, antioxidant and photocatalytic activities
Authors: P S Vindhya , R Kunjikannan , V T Kavitha
Published: December 2022

The present work aims to investigate the structural, optical, antimicrobial, antioxidant and photocatalytic activities of Zn1−xNixO (x = 0, 0.03, 0.05 & 0.07) nanoparticles prepared by the green method using Annona Muricata leaf extract. The synthesised nanoparticles were analysed by XRD, FTIR, XPS, HRTEM- SAED, SEM- EDX and UV-Visible spectroscopy. The XRD pattern confirms Ni has been successfully incorporated into the hexagonal wurtzite structure of ZnO. XPS results demonstrate the binding energies of ZnO and Ni. The presence of Zn-O vibrational modes was identified by FTIR spectra. The morphology of prepared samples was investigated through SEM and TEM analysis. The presence of Zn, O and Ni elements in EDX spectra indicates the purity of the sample. The optical bandgap energy of ZnO nanoparticles decreases with an increase in Ni concentration. Antimicrobial activity of nanoparticles were carried out against s.aureus, B.subtilis and P.aeruginosa bacterial strains as well as the fungal strain of A.niger and C.albicans. ZnO nanoparticles have significant antioxidant activity against DPPH free radicals. Under solar irradiation, Zn0.93Ni0.07O nanoparticles exhibit excellent photocatalytic degradation against malachite green (98.4 %) and methylene blue (94.9 %) dye solutions. Finally, these findings suggest an effective utilization of phytochemicals present in the A.muricata leaf extract as a suitable source for biosynthesis of pure and Ni-doped ZnO nanoparticles utilised for biomedical and industrial waste water treatment applications.
Nonlinear mixing-based terahertz emission in inclined rippled density plasmas
Authors: Gopal K , Singh A P , Divya S
Published: December 2022

We propose to investigate the THz field generation using nonlinear mixing mechanism of laser beat wave with inclined rippled density plasmas. Two laser pulses with frequencies (ω
1, ω
2) and wave vectors (k
1, k
2) co-propagate and resultant laser beat wave forms at beat frequency (ω
1–ω
2). Laser beat wave imparts a nonlinear force on the ambient electrons and pushes them outward with nonlinear velocity v
NL. Coupling of induced density perturbation and nonlinear velocity v
NL generates nonlinear currents at laser beat frequency that further generates electromagnetic field E
(ω
1–ω
2) in terahertz (THz) range. In the present scheme, density ripples are introduced at an angle with respect to laser propagation and flat Gaussian index (f) is introduced in laser field profile that transform curved top of Gaussian field envelope into flat top field envelope. The combined effect of flat laser pulses with inclined density ripples in plasmas shows 10-fold enhancement in THz field amplitude when flat-Gaussian index (f) varies from 1 to 4. Also, the THz field intensifies when density ripples inclination increases upto a certain angle and then decreases.
Beyond the Oberbeck–Boussinesq and long wavelength approximation
Authors: Held M. , Wiesenberger M.
Published: December 2022

We present the first simulations of a reduced magnetized plasma model that incorporates both arbitrary wavelength polarization and non-Oberbeck–Boussinesq effects. Significant influence of these two effects on the density, electric potential and

E
×
B

vorticity and non-linear dynamics of interchange blobs are reported. Arbitrary wavelength polarization implicates so-called gyro-amplification that compared to a long wavelength approximation leads to highly amplified small-scale

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B

vorticity fluctuations. These strongly increase the coherence and lifetime of blobs and alter the motion of the blobs through a slower blob-disintegration. Non-Oberbeck–Boussinesq effects incorporate plasma inertia, which substantially decreases the growth rate and linear acceleration of high amplitude blobs, while the maximum blob velocity is not affected. Finally, we generalize and numerically verify unified scaling laws for blob velocity, acceleration and growth rate that include both ion temperature and arbitrary blob amplitude dependence.
A method for increasing the yield of the suitable product of humic acids from raw materials using pulse-magnetic processing
Authors: Vasilyeva T I , Rodenko N A , Glushchenkov V A
Published: December 2022

The paper studied the effect of high-intensity pulsed magnetic fields (PMF) on extraction of humic acids in order to increase the yield of the suitable product. It is proposed to add to the technological chain of reactions for the precipitation of humic acids the operation of PMF processing of raw materials at the stage of the brawn coal suspension in alkali (the first experiment) or the alkaline extraction suspension (the second experiment).Pulse-magnetic processing the brawn coal suspension in alkali and the alkaline extraction suspension was carried out at magnetic field intensities H=0.09 106 A/m and H=0.82 106 A/m with the frequency of the discharge circuit f=40 kHz and the number of pulses n=1. The experiments have shown that when humic acids are obtained by water-alkaline extraction followed by their precipitation in an acid medium, for the highest yield of the product it is necessary to add the operation of pulse-magnetic processing a raw material at the magnetic field intensity of 0.82 106 A/m at the stage of the brawn coal suspension in alkali. It can be assumed that a high-intensity PMF contributes to the transfer of humic acids to a state conducive to their more efficient precipitation and extraction.
Use of a firebrand generator in the study of wildland and anthropogenic fires
Authors: Perminov V V , Kasymov D P
Published: December 2022

In this paper in order to conduct a laboratory experiment on the effect of firebrands on the ground cover, the material under study was collected on the territory of the Tomsk region, namely the bark. The sizes of the samples simulating firebrands were chosen in accordance with the data of field experiments, according to the results of which it was noted that particles of precisely this size prevail during the transfer of fire. The experiments were carried out using an installation for the generation of firebrands. To determine the temperature of the particles generated by the installation, the experiment was recorded using an infrared camera. As a result of a series of experiments on the installation for the generation of firebrands, it was found that burning particles of pine bark, as well as pine twigs, are transported over a distance of 5-8 m at an average speed of 3.6 m/s. As a result, it was revealed that the probability of ignition of the ground cover depends on its density, as well as on the size of particles, their number and wind speed.
Tropical cyclone intensity prediction by inter- and intra-pattern fusion based on multi-source data
Authors: Ma Dongfang , Wang Lingjie , Fang Sunke , Lin Jianmin
Published: December 2022

Tropical cyclones (TCs) are one of the most destructive natural disasters, which can bring huge life and economic losses to the global coastal areas. Accurate TC intensity prediction is critical for disaster prevention and loss reduction, but the dynamic processes involved in TCs are complicated and not adequately understood, which make the intensity prediction is still a challenging task. In recent years, several deep-learning (DL)-based methods have been developed for TC prediction by mining TC intensity series or related environmental factors. However, information hidden between the two different data sources is generally ignored. Here, a novel DL-based TC intensity prediction network named Pre_3D is proposed, which aimed to mine of inter- and intra-patterns of TC intensity and related external factors independently by separate feature extraction sub-networks. An MLP network is adopted to achieve adaptive fusion of the two patterns for accurate TCs intensity prediction. TC records from several agencies were used to evaluate generalizability of the proposed framework and extensive experiments were conducted validate its effectiveness. The experimental results demonstrate that the models based on the Pre_3D framework achieved considerable performance. ConvGRU-based Pre_3D yields a significant improvement of over 15% in prediction accuracy in 24 h prediction relative to official agencies.
Beneficial role of diurnal smoothing for grid integration of wind power
Authors: Gangopadhyay Anasuya , Seshadri Ashwin K , Toumi Ralf
Published: December 2022

Smoothing of generation variability, i.e. reduction of variance in the aggregate generation is crucial for grid integration of large-scale wind power plants. Prior studies of smoothing have focused on geographical smoothing, based on distance. In contrast, we propose a novel concept ‘diurnal smoothing’ that depends on spatial variations in the timing of seasonal-mean diurnal cycle peak. Considering the case of India, which experiences a strong diurnal cycle of wind-speed, we show how spatial heterogeneity in the wind diurnal cycle can be exploited to smooth wind power variability over and above geographical smoothing. For any given separation distance between sites, the hourly wind speed correlation is highly variable. Difference in timing of the diurnal cycle peak is an important factor for explaining this variability and we define smoothing from differently timed seasonal-mean diurnal cycle as ‘diurnal smoothing’. We show that apart from separation distance, the diurnal cycle is crucial for correlation among sites separated by 200 km or more with strong diurnal cycles (amplitude more than approximately 0.5 m s−1). Thus, diurnal smoothing is a vital factor in the aggregation of large wind power plants, and grid integration is benefited by considering (in addition to distance) new wind plant sites with largely separated diurnal cycles, especially those differing by roughly 12 h. Such diurnal smoothing is relevant for regions across the world with strong wind speed diurnal cycles. Ultimately grid integration depends on variations in total wind and solar generation and demand. Hence, their combined effects must be studied.