bluuebunny/crossref_metadata_2025 huggingface dataset:
Rare Intra-Aortic Migration of Temporary Epicardial Pacing Wire
Authors: Sharma Arun , Arya Shivali , Mahajan Sachin , Bansal Vidur , Singhal Manphool
Published: January 2023

Temporary epicardial pacing wires are used routinely in the postoperative period to prevent brady-arrythmias and maintain hemodynamic condition. Their safety and efficacy have been widely accepted with a low incidence of complications. Complications associated with temporary epicardial pacing wires may occur during removal or may be related to retained wires. Migration is one of the well-established but rare complications of retained epicardial pacing wire. Though migrations to various organs have been well documented in the literature, there are only few reports on intra-aortic migration of pacing wires in the postoperative period. Further, it is important for radiologists to know and identify these epicardial pacing wires as they may be associated with complications like superadded infection, migration to surrounding or distant areas, and injury to the heart and vessels.
COVID-19 Ramifications: A Scientific Approach to Bridge the Existing Gap between COVID Vaccines Hesitancy and Effectiveness
Authors: Nagy Hassan , Hameed Maha , Khan Faryal , Co Edzel Lorraine , Rauf Unaiza
Published: January 2023

The 2019 coronavirus disease (COVID-19) has been a major dilemma all over the world since December 2019. Several types of COVID-19 vaccines were developed for public utilization to halt the widespread of the disease; however, vaccine hesitancy is one major factor that prevents a successful control of this pandemic. This study aimed to summarize the different kinds of available COVID-19 vaccines and their effectiveness, and to assess the associated factors regarding vaccine hesitancy of the general population to bridge the gap existing between the two factors.1
3
Beyond CFD: Emerging methodologies for predictive simulation in cardiovascular health and disease
Authors: Schwarz Erica L. , Pegolotti Luca , Pfaller Martin R. , Marsden Alison L.
Published: January 2023

Physics-based computational models of the cardiovascular system are increasingly used to simulate hemodynamics, tissue mechanics, and physiology in evolving healthy and diseased states. While predictive models using computational fluid dynamics (CFD) originated primarily for use in surgical planning, their application now extends well beyond this purpose. In this review, we describe an increasingly wide range of modeling applications aimed at uncovering fundamental mechanisms of disease progression and development, performing model-guided design, and generating testable hypotheses to drive targeted experiments. Increasingly, models are incorporating multiple physical processes spanning a wide range of time and length scales in the heart and vasculature. With these expanded capabilities, clinical adoption of patient-specific modeling in congenital and acquired cardiovascular disease is also increasing, impacting clinical care and treatment decisions in complex congenital heart disease, coronary artery disease, vascular surgery, pulmonary artery disease, and medical device design. In support of these efforts, we discuss recent advances in modeling methodology, which are most impactful when driven by clinical needs. We describe pivotal recent developments in image processing, fluid–structure interaction, modeling under uncertainty, and reduced order modeling to enable simulations in clinically relevant timeframes. In all these areas, we argue that traditional CFD alone is insufficient to tackle increasingly complex clinical and biological problems across scales and systems. Rather, CFD should be coupled with appropriate multiscale biological, physical, and physiological models needed to produce comprehensive, impactful models of mechanobiological systems and complex clinical scenarios. With this perspective, we finally outline open problems and future challenges in the field.
Enhancement of skyrmion density via interface engineering
Authors: Bhatti Sabpreet , Tan H. K. , Sim M. I. , Zhang V. L. , Sall M. , Xing Z. X. , Juge R. , Mahendiran R. , Soumyanarayanan A. , Lim S. T. , Ravelosona D. , Piramanayagam S. N.
Published: January 2023

Magnetic skyrmions are promising candidates for computing and memory applications. The static and dynamic behaviors of skyrmions are tunable by altering the interfacial magnetic properties. These interfacial magnetic properties are alterable by modifying the interface structure of thin films. However, the relationship between the structural properties of the interface and the skyrmions properties is not straightforward, and a comprehensive insight is required to facilitate better controllability of the skyrmions’ behaviors. Here, we comprehensively understand the relationship between atomic displacements at the interface and skyrmions’ static behavior. In this study, we used ion irradiation to achieve inter-atomic displacements. We observed that the inter-atomic displacements could tailor the physical properties of skyrmions. We noticed a peculiar increase in the magnetization, Dzyaloshinskii–Moriya interaction, and exchange stiffness. The modifications in magnetic properties reduced the domain wall energy, which enhanced the skyrmion density (by six-folds) and reduced the average skyrmion diameter (by 50%). Furthermore, we compared the observed results of ion irradiation with those from the annealing process (a well-studied method for modifying magnetic properties) to better understand the effect of atomic displacements. Our study provides a route to achieve a highly-dense skyrmion state, and it can be explored further to suppress the skyrmion Hall effect for skyrmion-based applications.
Comparative studies of interatomic potentials for modeling point defects in wurtzite GaN
Authors: Lei Huaping , Chen Jun , Ruterana Pierre
Published: January 2023

In this paper, a new version of the Stillinger–Weber (SW) potential for wurtzite GaN is presented, by which we systematically explore the structural and thermodynamical properties of native point defects and their complexes. In parallel, the semi-empirical Modified Embedded-Atom Method (MEAM) potential is selected for comparison. The SW and MEAM potentials are assessed by the reproduction of the fundamental properties of wurtzite GaN and by the ability to describe the inversion domain boundaries and the wurtzite–rocksalt phase transition. Then the structural search of native point defects and their complexes in GaN is implemented using both SW and MEAM potentials with the benchmark of Density Functional Theory (DFT) calculations. Besides vacancies and antisites, four N and five Ga interstitials are confirmed by refining the DFT calculations, among which two N split interstitials N+−N⟨21̄1̄0⟩ and N+−Ga⟨011̄0⟩, and two Ga split interstitials, Ga+−Ga⟨011̄0⟩−g and Ga+−N⟨011̄0⟩, are observed for the first time. The SW potential correctly predicts the octahedral occupation GaOct to be the most stable Ga interstitial, while the MEAM potential predicts the ground state of the N+−N⟨011̄0⟩ split interstitial (N+−N⟨011̄0⟩−g) as the most stable N interstitial. However, neither of the two potentials could simultaneously generate the most stable configurations of N and Ga interstitials. The investigations of point defect complexes reveal that N octahedral Frenkel [FrenkelOct(N)] and paired antisite (NGaGaN) defects are unstable and get converted into VN⊕N+−N⟨011̄0⟩−g configurations with different separations between VN and N+−N⟨011̄0⟩−g point defects based on the DFT calculations. The formation energies calculated by the DFT and SW potential demonstrate that Schottky, Ga octahedral Frenkel [FrenkelOct(Ga)], and VN⊕N+−N⟨011̄0⟩−g point defect complexes are energetically feasible and that they should not dissociate into two isolated point defects. In contrast, the MEAM potential predicts the dissociation to be exothermic for Schottky and VN⊕N+−N⟨011̄0⟩−g. Overall, the structural features concerned with N–N or Ga–Ga bonds relaxed by the SW potential are more consistent with DFT calculations than the MEAM counterpart.
Synergistic prevention and reparative effects of sesquiterpene farnesol in a rabbit model of surgical resection-induced osteoarthritis
Authors: Chen Chun Yu , Kuo Shyh Ming , Wu Guan Xuan , Yang Shan Wei
Published: January 2023

Articular cartilage may regenerate poorly after injury or during aging. In vitro, farnesol can modulate extracellular matrix synthesis and restore chondrocyte phenotypes by increasing type II collagen (COL II) and glycosaminoglycan (GAG) production. Here, we evaluated farnesol's preventive and reparative effects against osteoarthritis (OA) in vivo. We induced OA in rabbits through resection of the lateral collateral ligament and meniscus. After 2 weeks, the affected limb was treated with 0.5 ml of 0.4 mM farnesol, hyaluronan (HA) nanoparticle-encapsulated 0.8 mM farnesol (Farn/HA), or HA nanoparticles intra-articularly. After 2 and 6 treatment weeks, synovial inflammatory cytokine levels were analyzed. We also removed the entire joint cartilage from lateral femoral condyles for histological investigation. The half-maximum inhibitory concentration of farnesol was 0.5 mM. Farn/HA had relatively low cytotoxicity showing cells remained viable after being treated with 1 mM a concentration Farn/HA. Untreated lateral condyle exhibited extensive wear. By contrast, 0.4 mM farnesol or 0.8 mM Farn/HA led to a relatively transparent and bright appearance. After 2 and 6 treatment weeks, farnesol, particularly 0.8 mM Farn/HA, reduced matrix metalloproteinase 1 and 13 levels considerably. Therefore, 0.8 mM Farn/HA, which enabled slow drug release, demonstrated the highest anti-inflammatory and OA preventive effects. After 6 treatment weeks, farnesol also promoted COL II and GAG synthesis and, thus, aided healing.
A guide to small fluorescent probes for single-molecule biophysics
Authors: Leake Mark C. , Quinn Steven D.
Published: January 2023

The explosive growth of single-molecule techniques is transforming our understanding of biology, helping to develop new physics inspired by emergent biological processes, and leading to emerging areas of nanotechnology. Key biological and chemical processes can now be probed with new levels of detail, one molecule at a time, from the nanoscopic dynamics of nature's molecular machines to an ever-expanding range of exciting applications across multiple length and time scales. Their common feature is an ability to render the underlying distribution of molecular properties that ensemble averaging masks and to reveal new insights into complex systems containing spatial and temporal heterogeneity. Small fluorescent probes are among the most adaptable and versatile for single-molecule sensing applications because they provide high signal-to-noise ratios combined with excellent specificity of labeling when chemically attached to target biomolecules or embedded within a host material. In this review, we examine recent advances in probe designs, their utility, and applications and provide a practical guide to their use, focusing on the single-molecule detection of nucleic acids, proteins, carbohydrates, and membrane dynamics. We also present key challenges that must be overcome to perform successful single-molecule experiments, including probe conjugation strategies, identify tradeoffs and limitations for each probe design, showcase emerging applications, and discuss exciting future directions for the community.
Structure and lithium insertion in oxides of molybdenum
Authors: Vincent Rebecca C. , Cheetham Anthony K. , Seshadri Ram
Published: January 2023

Oxides of molybdenum, MoOx, have a rich structural chemistry arising from the accommodation of oxygen deficiency as MoO3 is reduced and varied redox behavior arising from the ability of Mo to take on several different oxidation states. We review MoO3, MoO2, and all the reduced Mo oxides with intermediate compositions for their performance as Li-ion battery electrode materials. These reduced oxides are perhaps the most structurally diverse in the field of energy storage materials, taking on structures ranging from ones with crystallographic shear to bronze-like structures and distorted rutile. The crystal structure can have a significant impact on the performance of battery materials, which makes the reduced Mo oxides a promising domain of study. Electrochemical studies of these oxides from as early as 1971 to as recently as 2022 are compiled, and characteristics of capacity, capacity retention, and rate performance are compared. We find that certain oxides indeed display promising and highly reversible capacities for Li+ storage. Typical redox voltages for Mo oxides lie in a regime that hinders maximizing energy density when they are paired with higher-voltage cathodes or lower-voltage anodes. The possibility of decreasing the redox voltage in the future will expand the promise of these materials while offering an alternative to more critical elements such as Nb.
Chloroplasts in plant cells show active glassy behavior under low-light conditions
Authors: Schramma Nico , Perugachi Israëls Cintia , Jalaal Maziyar
Published: January 2023

Plants have developed intricate mechanisms to adapt to changing light conditions. Besides phototropism and heliotropism (differential growth toward light and diurnal motion with respect to sunlight, respectively), chloroplast motion acts as a fast mechanism to change the intracellular structure of leaf cells. While chloroplasts move toward the sides of the plant cell to avoid strong light, they accumulate and spread out into a layer on the bottom of the cell at low light to increase the light absorption efficiency. Although the motion of chloroplasts has been studied for over a century, the collective organelle motion leading to light-adapting self-organized structures remains elusive. Here, we study the active motion of chloroplasts under dim-light conditions, leading to an accumulation in a densely packed quasi-2D layer. We observe burst-like rearrangements and show that these dynamics resemble systems close to the glass transition by tracking individual chloroplasts. Furthermore, we provide a minimal mathematical model to uncover relevant system parameters controlling the stability of the dense configuration of chloroplasts. Our study suggests that the meta-stable caging close to the glass transition in the chloroplast monolayer serves a physiological relevance: Chloroplasts remain in a spread-out configuration to increase the light uptake but can easily fluidize when the activity is increased to efficiently rearrange the structure toward an avoidance state. Our research opens questions about the role that dynamical phase transitions could play in self-organized intracellular responses of plant cells toward environmental cues.
Topological Magnons in Kitaev Magnets with Finite Dzyaloshinskii-Moriya Interaction at High Field
Authors: Li Kangkang
Published: January 2023

There have been intensive studies on Kitaev materials for the sake of realization of exotic states such as quantum spin liquid and topological orders. In realistic materials, the Kitaev interaction may coexist with the Dzyaloshinskii–Moriya interaction, and it is of challenge to distinguish their magnitudes separately. Here, we study the topological magnon excitations and related thermal Hall conductivity of kagome magnet exhibiting Heisenberg, Kitaev and Dzyaloshinskii–Moriya interactions exposed to a magnetic field. In a strong magnetic field perpendicular to the plane of the lattice ([111] direction) that brings the system into a fully polarized paramagnetic phase, we find that the magnon bands carry nontrivial Chern numbers in the full region of the phase diagram. Furthermore, there are phase transitions related to two topological phases with opposite Chern numbers, which lead to the sign changes of the thermal Hall conductivity. In the phase with negative thermal conductivity, the Kitaev interaction is relatively large and the width of the phase increases with the strength of Dzyaloshinskii–Moriya interaction. Hence, the present study will contribute to the understanding of related compounds.
High-performance HZO/InAlN/GaN MISHEMTs for Ka-band application
Authors: Cui Peng , Moser Neil , Chen Hang , Xiao John Q , Chabak Kelson D , Zeng Yuping
Published: January 2023

This paper reports on the demonstration of microwave power performance at 30 GHz on InAlN/GaN metal–insulator–semiconductor high electron mobility transistor (MISHEMT) on silicon substrate by using the Hf0.5Zr0.5O2 (HZO) as a gate dielectric. Compared with Schottky gate HEMT, the MISHEMT with a gate length (L
G) of 50 nm presents a significantly enhanced performance with an ON/OFF current ratio (I
ON/I
OFF) of 9.3 × 107, a subthreshold swing of 130 mV dec−1, a low drain-induced barrier lowing of 45 mV V−1, and a breakdown voltage of 35 V. RF characterizations reveal a current gain cutoff frequency (f
T) of 155 GHz and a maximum oscillation frequency (f
max) of 250 GHz, resulting in high (f
T × f
max)1/2 of 197 GHz and the record high Johnson’s figure-of-merit (JFOM = f
T × BV) of 5.4 THz V among the reported GaN MISHEMTs on Si. The power performance at 30 GHz exhibits a maximum output power of 1.36 W mm−1, a maximum power gain of 12.3 dB, and a peak power-added efficiency of 21%, demonstrating the great potential of HZO/InAlN/GaN MISHEMTs for the Ka-band application.
Active adjustment of space-borne cable-net antenna via a two-way shape memory alloy spring
Authors: Zhang Jiacheng , Zhang Yiqun , He Yongxi , Yang Dongwu , Sun Zihan , Xiong Jichuan , Yang Jianli
Published: January 2023

In extreme space environments with alternating and uneven temperature variations, the surface accuracy of cable-net antennas deteriorates significantly, thereby inducing a periodic failure or a significant deviation in the electrical performance. This is because of the lack of effective methods for controlling the surface shape during the service of the cable-net antenna. In this study, a method based on ‘two-way memory spring’ is proposed to actively control the surface of a cable-net antenna. Herein, first, an electro-thermo-mechanical model of the shape memory alloy (SMA) spring is deduced by combining the intrinsic model of the two-way shape memory effect and the resistance property of the SMA. Subsequently, a principle prototype is developed, and experiments related to active control are conducted to confirm the feasibility and effectiveness of the proposed method.
Valley-polarized and supercollimated electronic transport in an 8-Pmmn borophene superlattice
Authors: Xu Yafang , Fang Yu , Jin Guojun
Published: January 2023

Analogous to real spins, valleys as carriers of information can play significant roles in physical properties of two-dimensional Dirac materials. On the other hand, utilizing external periodic potential is an efficient method to manipulate their band structures and transport properties. In this work, we investigate the valley dependent optics-like behaviors based on an 8-Pmmn borophene superlattice with the transfer matrix method and effective band approach. Firstly, it is found that the band structure is renormalized, more tilted Dirac cones are generated, and the group velocities are modified by the periodic potentials. Secondly, due to the exotic tilted Dirac cones in 8-Pmmn borophene, a perfect valley selected angle filter can be realized. The electrons with a specific incident angle can transmit completely in an energy window, which is flexibly tunable by changing the periodic potential. Thirdly, by using the Green’s function to simulate the time evolution of wave packets, electrons can be shown to propagate without any diffraction, valley electron beam supercollimation happens by modulating the potential parameters. Different from the graphene superlattice, the electron supercollimation here is valley dependent and can be used as a valley electron beam collimator. Fourthly, we can tune the polarization and supercollimation angles by changing the superlattice direction. These intriguing results in an 8-Pmmn borophene-based superlattice offer more opportunities in diverse electronic transport phenomena and may facilitate the devices applications in valleytronics and electron-optics.
Comments on the paper ‘Comparison study of bound states for diatomic molecules using Kratzer, Morse, and modified Morse potentials’
Authors: Samant R , Lotliker S U , Desai A M
Published: January 2023

Al-Othman et al (2022, Phys. Scr.
97 035401) in their paper have compared the energy eigenvalues obtained using Kratzer, Morse, and modified Morse potentials for four diatomic molecules (H2, N2, CO, and HCl) using the shifted 1/N expansion method. We show that due to the wrong expression of the parameter used in the modified Morse potential, the energy eigenvalues obtained for the case of modified Morse potential are incorrect, and the interpretation of the results stated in this paper is not reliable. We have rectified the error and recalculated the vibrational energy eigenvalues for the ground state of the HCl molecule using the shifted 1/N expansion method and compared the accuracy of Kratzer, Morse, and modified Morse with that of the observed vibrational energy eigenvalues. Also, we have determined the energy eigenvalues for the ground state of the HCl molecule by numerically solving the Schrödinger equation for the case of the modified Morse potential and compared the accuracy with the values obtained using the shifted 1/N expansion method. The vibrational energy eigenvalues obtained using modified Morse for the HCl molecule are found to be closer to the observed values than the Morse and Kratzer potential functions.
Controllability of fractional dynamical systems with ψ-Caputo fractional derivative
Authors: Selvam A Panneer , Vellappandi M , Govindaraj V
Published: January 2023

The idea behind this study is to investigate the controllability of dynamical systems in terms of theψ-Caputo fractional derivative. The Grammian matrix is used to get at necessary and sufficient controllability requirements for linear systems, which are characterized by the Mittag-Leffler functions, while the fixed point approach is used to arrive at adequate controllability criteria for nonlinear systems. The novelty of this research is to inquire into the controllability concepts by utilizing theψ-Caputo fractional derivative. Sinceψ-Caputo fractional derivatives have the advantage of capturing memory effects as well as increasing the accuracy of anticipating real-world scenarios. A few numerical examples are offered to help better understand the theoretical results.
Influence of the A-site cation on structural, morphological, magnetic, optical and transport properties of R2CoMnO6(R = Nd, Y, Ho and Er) double perovskite oxides
Authors: Nissar Umair , Ahmad Javed
Published: January 2023

The A-site substituted double perovskite oxides (DPOs) have in the recent decades gained much attention due to their various interesting properties and possible applications. For this reason, R2CoMnO6 (R = Nd, Y, Ho, and Er) DPOs have been synthesized using the auto-combustion sol-gel method. X-ray diffraction analysis suggests the crystal structure, i.e., monoclinic for all under-investigated DPOs at room temperature (RT), consisting of space group P2

1

/n which is confirmed by Rietveld refinement. Crystallite size is calculated using Scherrer and Williamson-Hall methods, and it was found that the crystallite size decreased with decreasing ionic radii from 55–29 nm on average. The micrographs were obtained by using a field-emission scanning electron microscope (FE-SEM), which reveals an almost homogeneous distribution of grains throughout the surface of all DPOs. All observed infrared and Raman active phonon modes have been assigned to vibrations of atoms and groups of atoms consistent with the prediction of group theory. The intermediate band gap values (1.34–1.63 eV) determined by the Tauc relations suggest the semiconducting nature of these DPOs which makes them promising materials for photovoltaic applications. Dc electrical resistivity and dielectric measurements also suggest semiconducting behaviour above ambient temperature, which is attributed to a small polaron hopping conduction mechanism. The Maxwell-Wagner type interfacial polarization has described the nature of the frequency-dependent dielectric constants in these DPOs. The dielectric (ac) study also suggests the small polaron hopping conduction mechanism in all samples, which supports our findings in resistivity measurements.
Fast-forward adiabatic quantum dynamics of XY spin model on three spin system
Authors: Setiawan Iwan , Ekawita Riska , Sugihakim Ryan , Gunara Bobby Eka
Published: January 2023

We discussed a method to accelerate an adiabatic quantum dynamics of XY spin model by using the fast-forward method proposed by Masuda and Nakamura. The Accelerated scheme is constructed by adding the driving Hamiltonian to the original Hamiltonian and speeding it up with a large time-scaling factor and an adiabatic parameter that realizes adiabatic quantum dynamics in a shortened time. Accelerated adiabatic dynamics start by assuming the candidate of driving Hamiltonian consists of the pair-wise exchange interaction and magnetic field. The driving Hamiltonian terms multiplied by the velocity function together with the original Hamiltonian give fast-forward driving for adiabatic states. We apply our method to XY spin model by considering three spin systems on the Kagome lattice. In this model, we obtained the XY pair-wise exchange interaction of nearest neighbors and next-nearest neighbors should be added to the original Hamiltonian as a driving interaction to accelerate the adiabatic motion. This pair-wise driving interaction in the fast-forward scheme guarantees the complete fidelity of accelerated states.
Testing quantum computers with the protocol of quantum state matching
Authors: Ortega Adrian , Kálmán Orsolya , Kiss Tamás
Published: January 2023

The presence of noise in quantum computers hinders their effective operation. Even though quantum error correction can theoretically remedy this problem, its practical realization is still a challenge. Testing and benchmarking noisy, intermediate-scale quantum (NISC) computers is therefore of high importance. Here, we suggest the application of the so-called quantum state matching protocol for testing purposes. This protocol was originally proposed to determine if an unknown quantum state falls in a prescribed neighborhood of a reference state. We decompose the unitary specific to the protocol and construct the quantum circuit implementing one step of the dynamics for different characteristic parameters of the scheme and present test results for two different IBM quantum computers. By comparing the experimentally obtained relative frequencies of success to the ideal success probability with a maximum statistical tolerance, we discriminate statistical errors from device specific ones. For the characterization of noise, we also use the fact that while the output of the ideal protocol is insensitive to the internal phase of the input state, the actual implementation may lead to deviations. For systematically varied inputs we find that the device with the smaller quantum volume performs better on our tests than the one with larger quantum volume, while for random inputs they show a more similar performance.
Skyrmion state stabilized by short-range interactions in centrosymmetric materials
Authors: Li W C , Liu Z Q , Xie D , Yao X W
Published: January 2023

Magnetic frustration can induce interesting magnetic phases including skyrmion state in centrosymmetric materials. By means of Monte Carlo simulations, we theoretically study the frustrated J
1–J
2 classical Heisenberg model on the triangular lattice. Both h
1–J
2 and h–T phase diagrams show rich magnetic phases, and skyrmion state can be stabilized by J
2. These results can be qualitatively explained by energy competitions, and indicate that skyrmion can be driven by the competition of short-range interactions in absence of DM interaction. This may help us to design and apply the skyrmion devices more easily in the future.
A novel chaotic map with a shifting parameter and stair-like bifurcation diagram: dynamical analysis and multistability
Authors: Ramadoss Janarthanan , Natiq Hayder , Nazarimehr Fahimeh , He Shaobo , Rajagopal Karthikeyan , Jafari Sajad
Published: January 2023

In this paper, the behavior of a 1D chaotic map is proposed which includes two sine terms and shows unique dynamics. By varying the bifurcation parameter, the map has a shift, and the system’s dynamics are generated around the cross points of the map and the identity line. The irrational frequency of the sine term makes the system have stable fixed points in some parameter intervals by increasing the bifurcation parameter. So, the bifurcation diagram of the system shows that the trend of the system’s dynamics changes in a stair shape with slope one by changing the bifurcation parameter. Due to the achieving multiple steady states in some intervals of the parameter, the proposed system is known as multistable. The multistability dynamics of the map are investigated with the help of cobweb diagrams which reveal an interesting asymmetry in repeating parts of the bifurcation diagram.
Limits on the nuclearite flux using the ANTARES neutrino telescope
Authors: Albert A. , Alves S. , André M. , Ardid M. , Ardid S. , Aubert J.-J. , Aublin J. , Baret B. , Basa S. , Belhorma B. , Bendahman M. , Benfenati F. , Bertin V. , Biagi S. , Bissinger M. , Boumaaza J. , Bouta M. , Bouwhuis M.C. , Brânzaş H. , Bruijn R. , Brunner J. , Busto J. , Caiffi B. , Calvo D. , Capone A. , Caramete L. , Carr J. , Carretero V. , Celli S. , Chabab M. , Chau T. N. , Cherkaoui El Moursli R. , Chiarusi T. , Circella M. , Coelho J.A.B. , Coleiro A. , Coniglione R. , Coyle P. , Creusot A. , Díaz A.F. , de Wasseige G. , De Martino B. , Distefano C. , Di Palma I. , Domi A. , Donzaud C. , Dornic D. , Drouhin D. , Eberl T. , van Eeden T. , van Eijk D. , El Khayati N. , Enzenhöfer A. , Fermani P. , Ferrara G. , Filippini F. , Fusco L. , García J. , Gay P. , Glotin H. , Gozzini R. , Gracia Ruiz R. , Graf K. , Guidi C. , Hallmann S. , van Haren H. , Heijboer A.J. , Hello Y. , Hernández-Rey J.J. , Hößl J. , Hofestädt J. , Huang F. , Illuminati G. , James C.W. , Jisse-Jung B. , de Jong M. , de Jong P. , Kadler M. , Kalekin O. , Katz U. , Kouchner A. , Kreykenbohm I. , Kulikovskiy V. , Lahmann R. , Lamoureux M. , Le Breton R. , Lefèvre D. , Leonora E. , Levi G. , Le Stum S. , Lopez-Coto D. , Loucatos S. , Maderer L. , Manczak J. , Marcelin M. , Margiotta A. , Marinelli A. , Martínez-Mora J.A. , Melis K. , Migliozzi P. , Moussa A. , Muller R. , Nauta L. , Navas S. , Nezri E. , Ó Fearraigh B. , Păun A. , Păvălaş G.E. , Pellegrino C. , Perrin-Terrin M. , Pestel V. , Piattelli P. , Pieterse C. , Poirè C. , Popa V. , Pradier T. , Randazzo N. , Real D. , Reck S. , Riccobene G. , Romanov A. , Sánchez-Losa A. , Salesa Greus F. , Samtleben D. F. E. , Sanguineti M. , Sapienza P. , Schnabel J. , Schumann J. , Schüssler F. , Seneca J. , Spurio M. , Stolarczyk Th. , Taiuti M. , Tayalati Y. , Tingay S.J. , Vallage B. , Van Elewyck V. , Versari F. , Viola S. , Vivolo D. , Wilms J. , Zavatarelli S. , Zegarelli A. , Zornoza J.D. , Zúñiga J.
Published: January 2023

In this work, a search for nuclearites of strange quark matter by using nine years of ANTARES data taken in the period 2009–2017 is presented. The passage through matter of these particles is simulated taking into account a detailed description of the detector response to nuclearites and of the data acquisition conditions. A down-going flux of cosmic nuclearites with Galactic velocities (β = 10-3) was considered for this study. The mass threshold for detecting these particles at the detector level is 4 × 1013 GeV/c
2. Upper limits on the nuclearite flux for masses up to 1017 GeV/c
2 at the level of ∼ 5 × 10-17 cm-2 s-1 sr-1 are obtained. These are the first upper limits on nuclearites established with a neutrino telescope and the most stringent ever set for Galactic velocities.
Constraints on early dark energy from the axion weak gravity conjecture
Authors: Rudelius Tom
Published: January 2023

A popular proposal for resolving the Hubble tension involves an early phase of dark energy, driven by an axion field with a periodic potential. In this paper, we argue that these models are tightly constrained by the axion weak gravity conjecture: for typical parameter values, the axion decay constant must satisfy f < 0.008,M
Pl, which is smaller than the axion decay constants appearing in the vast majority of early dark energy models to date. We discuss possible ways to evade or loosen this constraint, arguing that its loopholes are small and difficult to thread. This suggests that it may prove challenging to realize early dark energy models in a UV complete theory of quantum gravity.
Enhance primordial black hole abundance through the non-linear processes around bounce point
Authors: Chen Jie-Wen , Zhu Mian , Yan Sheng-Feng , Wang Qing-Qing , Cai Yi-Fu
Published: January 2023

The non-singular bouncing cosmology is an alternative paradigm to inflation,
wherein the background energy density vanishes at the bounce point, in the context of Einstein gravity.
Therefore, the non-linear effects in the evolution of density fluctuations (δρ) may be strong in the bounce phase,
which potentially provides a mechanism to enhance the abundance of primordial black holes (PBHs).
This article presents a comprehensive illustration for PBH enhancement due to the bounce phase.
To calculate the non-linear evolution of δρ, the Raychaudhuri equation is numerically solved here.
Since the non-linear processes may lead to a non-Gaussian probability distribution function for δρ after the bounce point,
the PBH abundance is calculated in a modified Press-Schechter formalism.
In this case, the criterion of PBH formation is complicated,
due to complicated non-linear evolutionary behavior of δρ during the bounce phase.
Our results indicate that the bounce phase indeed has potential to enhance the PBH abundance sufficiently.
Furthermore, the PBH abundance is applied to constrain the parameters of bounce phase,
providing a complementary to the surveys of cosmic microwave background and large scale structure.
Complexity of charged anisotropic spherically symmetric fluids in

f()

gravity
Authors: Yousaf Z , Bhatti M Z , Nasir M M M
Published: January 2023

The previous ideology of complexity factor for the dynamical spheres [Herrera et al 2018, Phys. Rev. D, 98, 104059] is extended for the influence of charge. A dynamical spherically symmetric non-dissipative and dissipative self-gravitating structure is examined in the presence of Maxwell

f
(

)

gravity to examine the complexity factor. The pattern of evolution is studied with the minimal complexity constraint. The complexity factor remains the same for the structure of fluid distribution, while we examine homologous constraints for the most basic evolution pattern. We calculate the structure scalars which play an important role in order to understand the fundamental properties of the system. The fluid is geodesic as well as shearing for the dissipative case and there is a large number of solutions. In the non-dissipative fluid distribution, a shear-free, homogeneous and isotropic, geodesic fluid correlates with the evolving homologous and vanishing complexity condition. The implication of the condition of vanishing complexity factor and stability are discussed at the end.
Machine learning of the Γ-point gap and flat bands of twisted bilayer graphene at arbitrary angles
Authors: Ma Xiaoyi , Luo Yufeng , Li Mengke , Jiao Wenyan , Yuan Hongmei , Liu Huijun , Fang Ying
Published: January 2023

The novel electronic properties of bilayer graphene can be fine-tuned via twisting, which may induce flat bands around the Fermi level with nontrivial topology. In general, the band structure of such twisted bilayer graphene (TBG) can be theoretically obtained by using first-principles calculations, tight-binding method, or continuum model, which are either computationally demanding or parameters dependent. In this work, by using the sure independence screening sparsifying operator method, we propose a physically interpretable three-dimensional (3D) descriptor which can be utilized to readily obtain the Γ-point gap of TBG at arbitrary twist angles and different interlayer spacings. The strong predictive power of the descriptor is demonstrated by a high Pearson coefficient of 99% for both the training and testing data. To go further, we adopt the neural network algorithm to accurately probe the flat bands of TBG at various twist angles, which can accelerate the study of strong correlation physics associated with such a fundamental characteristic, especially for those systems with a larger number of atoms in the unit cell.
Mapping the representativeness of precipitation measurements in Mainland China
Authors: Zhang Yan , Wang Kaicun
Published: January 2023

Meteorological observations provide essential data for weather forecasting and climate change studies. Whether the measured data can accurately support such applications closely relates to the representativeness of the data collected, which depends on both the scale of observation and the density of the measurement network. Precipitation presents in the form of events and is discontinuous both in time and space. Gauge observations of precipitation could provide fundamental data but have difficulty quantitatively assessing precipitation system scale. Therefore, assessments on the representativeness of precipitation at synoptic and climatological scales remain needed. Here, we show the first high-resolution map of the representativeness of precipitation over Mainland China based on the latest satellite data. Our results show that the daily precipitation spatial consistency is the highest in eastern China and lowest on the Tibetan Plateau. However, the pattern of the monthly spatial consistency is different and is the highest over Northeast China Plain, the Loess Plateau, and the Middle–Lower Yangtze Plain. Compared to the density of rain gauges, we find that the current national station network with ∼2400 stations still has difficulty supporting synoptic studies in western China. However, for climate change studies based on monthly data, the density of the national reference climatological station network is sufficient, except in the western Tibetan Plateau and deserts with no available stations. For climatological studies, the quality of precipitation gauge observations is more important than its spatial density. Our results could provide great practical significance for considering the layout of rain gauges.
Preparation and properties of epoxy resin modified with phosphorus and nitrogen flame retardants
Authors: Wang Chenghui , Zhang Yingqiang , Wang Xinyu
Published: January 2023

Epoxy resins (EPs) require the addition of flame retardants to extend their application scope. High-efficiency flame retardants typically contain halogens, which can cause tremendous harm to humans and the environment. In this study, we investigated the syntheses of new phosphorus–nitrogen flame retardants (DIT) and flame-retardant EP. DIT is composed of 6-(2,5-dihydroxyphenyl) dibenzo[c,e][1,2] oxaphosphinine 6-oxide, 5-isocyanato-1-(isocyanatomethyl)−1,3,3-trimethylcyclohexane, and tris-(2-hydroxyethyl) isocyanurate. DIT chemical structure was analysed by Fourier-transform infrared spectroscopy. Several formulations of modified epoxy resins (DIT-EPs) were obtained by adding different quantities of DITs. We found that when the flame retardant content reached 25%, the limiting oxygen index of the DIT-EP was 29.0%. This finding expands the application range of EPs.
Optimization of adsorption of methyl orange from aqueous solution by magnetic CoFe2O4/ZnAl-layered double hydroxide composite using response surface methodology
Authors: Desalegn Yiene Molla , Bekele Endrias Adane , Amibo Temesgen Abeto , Desissa Temesgen Debelo
Published: January 2023

The CoFe2O4/ZnAl-layered double hydroxide (LDH) composite was successfully developed through a facile co-precipitation method, characterized, and applied as an effective adsorbent for the removal of methyl orange (MO) dye from aqueous solutions. The central composite design (CCD) of the response surface methodology (RSM) was employed to estimate and optimize process variables such as initial MO concentrations, solution pH, adsorbent dosage, and contact time. 98.878% adsorption efficiency was obtained at an initial concentration of 18.747 mg l−1 of MO, with an adsorbent dosage of 0.048 g, a solution pH of 2.770, and a contact time of 85.890 min. Analysis of variance (ANOVA) confirmed the significance of the predicted model (R2 = 0.9844). Kinetic and equilibrium studies indicated that the experimental data for MO adsorption were best described by pseudo-second-order kinetic and Langmuir models. The maximum monolayer adsorption capacity of the CoFe2O4/ZnAl-LDH for MO was 42.3 mg g−1.
Local wavelength evolution and Landau damping of electrostatic plasma wave driven by an ultra-relativistic electron beam in dense inhomogeneous plasma
Authors: LI Ran , HUANG Taiwu , YU Mingyang , ZHOU Cangtao , RUAN Shuangchen
Published: January 2023

Evolution of an electrostatic plasma wave driven by a low-density ultra-relativistic electron beam in dense inhomogeneous plasma is considered. In particular, the wavelength variation as observed at fixed locations in the plasma is analyzed in terms of the wave characteristics. It is shown that for a negative density gradient, the observed local wavelength decreases monotonically with time, but for a positive density gradient, it first increases and then decreases with time, accompanied by reversal of the wave phase. However, in both cases the local wavelength eventually decreases with time since Landau damping becomes significant as the wavelength becomes of the order of the plasma Debye length. Results from particle-in-cell simulations agree well with theoretical analyses of the wavelength variation.
Investigation of gyrotron-based collective Thomson scattering for fast ion diagnostics in a compact high-field tokamak
Authors: XU Dengfeng , HUANG Mei , CHEN Xixuan , ZHANG Feng , XIA Donghui , WANG Zhijiang , PAN Yuan
Published: January 2023

As a promising method for fast ion diagnostics, collective Thomson scattering (CTS) can measure the one-dimensional velocity distribution of fast ions with high spatial and temporal resolution. The feasibility of diagnosing fast ions in a compact high-field tokamak by CTS was studied in this work, and the results showed that a wide range of probing frequencies could be applied. A high-frequency case and a low-frequency case were mainly considered for fast ion diagnostics in a compact high-field tokamak. The use of a high probing frequency could effectively avoid the refraction effect of the beams, while the application of a low probing frequency allows greater flexibility in the selection of scattering angle which may help to improve the spatial resolution. Based on typical plasma conditions (B
0 = 12.2 T, n
e0 = 4.3 × 1020 m−3, T
e0 = 22.2 keV, T
i0 = 19.8 keV) for a compact high-field tokamak, a 220 GHz CTS diagnostic that utilizes a small scattering angle of θ = 30° and a 160 GHz CTS diagnostic that utilizes an orthogonal geometry were proposed. Further study showed that the high-frequency case could operate in a wider range of plasma conditions and provide more information on fast ions while the low-frequency case could achieve higher spatial resolution of the poloidal direction.
Flip chip bonding on stretchable printed substrates; the effects of stretchable material and chip encapsulation
Authors: Malik Muhammad Hassan , Kaczynski Jaroslaw , Zangl Hubert , Roshanghias Ali
Published: January 2023

Stretchable printed electronics have recently opened up new opportunities and applications, including soft robotics, electronic skins, human-machine interfaces, and healthcare monitoring. Stretchable hybrid systems (SHS) leverage the benefits of low-cost fabrication of printed electronics with high-performance silicon technologies. However, direct integration of silicon-based devices on conventional stretchable substrates such as thermoplastic polyurethane (TPU) and polydimethylsiloxane (PDMS) is extremely challenging due to their restricted low-temperature processing. In this study, a recently developed thermoset, stretchable substrate (BeyolexTM) with superior thermal and mechanical properties was employed to realize SHS via direct flip chip bonding. Here, ultra-thin chips (UTC) with a fine-pitch, daisy-chain structure was flip-chip bonded by using anisotropic conductive adhesives, while the complementary circuitry was facilitated via screen-printed, stretchable silver tracks. The bonded samples successfully passed reliability assessments after being subjected to cyclic 30% stretch tests for 200 cycles. The potential benefits of chip encapsulation after integration with the stretchable substrate to withstand larger strains were demonstrated by both mechanical simulation and experimental results.
A recipe for cracking the quantum scaling limit with machine learned electron densities
Authors: Rackers Joshua A , Tecot Lucas , Geiger Mario , Smidt Tess E
Published: January 2023

A long-standing goal of science is to accurately simulate large molecular systems using quantum mechanics. The poor scaling of current quantum chemistry algorithms on classical computers, however, imposes an effective limit of about a few dozen atoms on traditional electronic structure calculations. We present a machine learning (ML) method to break through this scaling limit for electron densities. We show that Euclidean neural networks can be trained to predict molecular electron densities from limited data. By learning the electron density, the model can be trained on small systems and make accurate predictions on large ones. In the context of water clusters, we show that an ML model trained on clusters of just 12 molecules contains all the information needed to make accurate electron density predictions on cluster sizes of 50 or more, beyond the scaling limit of current quantum chemistry methods.
Machine and quantum learning for diamond-based quantum applications
Authors: Stone Dylan G , Bradac Carlo
Published: January 2023

In recent years, machine and quantum learning have gained considerable momentum sustained by growth in computational power and data availability and have shown exceptional aptness for solving recognition- and classification-type problems, as well as problems that require complex, strategic planning. In this work, we discuss and analyze the role machine and quantum learning are playing in the development of diamond-based quantum technologies. This matters as diamond and its optically addressable spin defects are becoming prime hardware candidates for solid state-based applications in quantum information, computing and metrology. Through a selected number of demonstrations, we show that machine and quantum learning are leading to both practical and fundamental improvements in measurement speed and accuracy. This is crucial for quantum applications, especially for those where coherence time and signal-to-noise ratio are scarce resources. We summarize some of the most prominent machine and quantum learning approaches that have been conducive to the presented advances and discuss their potential, as well as their limits, for proposed and future quantum applications.