bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrostatic lower hybrid turbulence due to magnetic islands and particle heating in magnetopause reconnection regions
Authors: Upadhyay Manoj K. , Uma R. , Sharma R. P.
Published: July 2023

This investigation presents a model to understand the magnetopause turbulence in the lower hybrid frequency range at reconnection regions as observed by the magnetospheric multiscale mission. We have modeled 3D electrostatic lower hybrid wave (LHW) in cold magnetized plasma in the presence of magnetic islands. In this model, we have developed the modified nonlinear Schrödinger equation, contemplating that nonlinear effects are due to ponderomotive force. The dynamical equation of the system thus obtained is solved using numerical simulation techniques. The simulation results illustrate the formation and evolution of localized structures and the current sheets. Due to the nonlinear effects and magnetic reconnection, the current sheets become turbulent with time. A semi-analytical model is also given to illustrate the scale size of current sheets. The turbulent power spectra have also been studied. The spectral index of the power spectrum is found to be −2.7 (approximately) in the perpendicular direction and −2.2 (approximately) in the parallel direction, indicating anisotropy. Using the Folker–Plank diffusion equation with the new velocity space diffusion coefficient, we find the distribution function of energetic electrons due to these turbulent structures. We propose that LHW may be responsible for plasma heating in magnetopause.
Gaussian functions with odd power of r produced by the free complement theory
Authors: Kurokawa Yusaku I. , Nakatsuji Hiroshi
Published: July 2023

We investigate, in this paper, the Gaussian (G) function with odd powers of r, rxaybzc exp(−αr2), called the r-Gaussian or simply the rG function. The reason we investigate this function here is that it is generated as the elements of the complement functions (cf’s) when we apply the free complement (FC) theory for solving the Schrödinger equation to the initial functions composed of the Gaussian functions. This means that without the rG functions, the Gaussian set of functions cannot produce the exact solutions of the Schrödinger equation, showing the absolute importance of the rG functions in quantum chemistry. Actually, the rG functions drastically improve the wave function near the cusp region. This was shown by the applications of the present theory to the hydrogen and helium atoms. When we use the FC-sij theory, in which the inter-electron function rij is replaced with its square sij=rij2 that is integrable, we need only one- and two-electron integrals for the G and rG functions. The one-center one- and two-electron integrals of the rG functions are always available in a closed form. To calculate the integrals of the multi-centered rG functions, we proposed the rG-NG expansion method, in which an rG function is expanded by a linear combination of the G functions. The optimal exponents and coefficients of this expansion were given for N = 2, 3, 4, 5, 6, and 9. To show the accuracy and the usefulness of the rG-NG method, we applied the FC-sij theory to the hydrogen molecule.
Large ordered moment with strong easy-plane anisotropy and vortex-domain pattern in the kagome ferromagnet Fe3Sn
Authors: Prodan Lilian , Evans Donald M. , Griffin Sinéad M. , Östlin Andreas , Altthaler Markus , Lysne Erik , Filippova Irina G. , Shova Sergiu , Chioncel Liviu , Tsurkan Vladimir , Kézsmárki István
Published: July 2023

We report the magnetic anisotropy of kagome bilayer ferromagnet Fe3Sn probed by the bulk magnetometry and magnetic force microscopy (MFM) on high-quality single crystals. The dependence of magnetization on the orientation of the external magnetic field reveals strong easy-plane magnetocrystalline anisotropy and anisotropy of the saturation magnetization. The leading magnetocrystalline anisotropy constant shows a monotonous increase from K1≈−1.0×106 J/m3 at 300 K to −1.3×106 J/m3 at 2 K. Our ab initio electronic structure calculations yield the value of total magnetic moment of 7.1 μB/f.u. and a magnetocrystalline anisotropy energy density of −0.57 meV/f.u. (−1.62×106J/m3) both being in reasonable agreement with the experimental values. The MFM imaging reveals micrometer-scale magnetic vortices with weakly pinned cores that vanish at the saturation field of ∼3 T applied perpendicular to the kagome plane. The observed vortex-domain structure is well reproduced by the micromagnetic simulations, using the experimentally determined value of the anisotropy and exchange stiffness.
Cross-platform hyperparameter optimization for machine learning interatomic potentials
Authors: Thomas du Toit Daniel F. , Deringer Volker L.
Published: July 2023

Machine-learning (ML)-based interatomic potentials are increasingly popular in material modeling, enabling highly accurate simulations with thousands and millions of atoms. However, the performance of machine-learned potentials depends strongly on the choice of hyperparameters—that is, of those parameters that are set before the model encounters data. This problem is particularly acute where hyperparameters have no intuitive physical interpretation and where the corresponding optimization space is large. Here, we describe an openly available Python package that facilitates hyperparameter optimization across different ML potential fitting frameworks. We discuss methodological aspects relating to the optimization itself and to the selection of validation data, and we show example applications. We expect this package to become part of a wider computational framework to speed up the mainstream adaptation of ML potentials in the physical sciences.
How can machine learning be used for accurate representations and predictions of fracture nucleation in zirconium alloys with hydride populations?
Authors: Hasan T. , Capolungo L. , Zikry M. A.
Published: July 2023

Zirconium alloys are critical material components of systems subjected to harsh environments such as high temperatures, irradiation, and corrosion. When exposed to water in high temperature environments, these alloys can thermo-mechanically degrade by forming hydrides that have a crystalline structure that is different from that of zirconium. Cracks can nucleate near these hydrides; hence, these hydrides are a direct link to fracture failure and overall large inelastic strain deformation modes. To fundamentally understand and predict these microstructural failure modes, we interrogated a finite-element database that was deterministically tailored and generated for large strain-dislocation-density crystalline plasticity and fracture modes. A database of 210 simulations was created to randomly sample from a group of microstructural fingerprints that encompass hydride volume fraction, hydride orientation, grain orientation, hydride length, and hydride spacing for a hydride that is physically representative of an aggregate of a hydride population. Machine learning approaches were then used to understand, identify, and characterize the dominant microstructural mechanisms and characteristics. We first used fat-tailed Cauchy distributions to determine the extreme events. A multilayer perceptron was used to learn the mechanistic characteristics of the material response to predefined strain levels and accurately determine the critical fracture stress response and the accumulated shear slips in critical regions. The predictions indicate that hydride volume fraction, a population-level parameter, had a significant effect on localized parameters, such as fracture stress distribution regions, and on the accumulated immobile dislocation densities both within the face centered cubic hydrides and the hexagonal cubic packed h.c.p. matrix.
Generating candidates in global optimization algorithms using complementary energy landscapes
Authors: Slavensky Andreas Møller , Christiansen Mads-Peter V. , Hammer Bjørk
Published: July 2023

Global optimization of atomistic structure relies on the generation of new candidate structures in order to drive the exploration of the potential energy surface (PES) in search of the global minimum energy structure. In this work, we discuss a type of structure generation, which locally optimizes structures in complementary energy (CE) landscapes. These landscapes are formulated temporarily during the searches as machine learned potentials (MLPs) using local atomistic environments sampled from collected data. The CE landscapes are deliberately incomplete MLPs that rather than mimicking every aspect of the true PES are sought to become much smoother, having only a few local minima. This means that local optimization in the CE landscapes may facilitate the identification of new funnels in the true PES. We discuss how to construct the CE landscapes and we test their influence on the global optimization of a reduced rutile SnO2(110)-(4  × 1) surface and an olivine (Mg2SiO4)4 cluster for which we report a new global minimum energy structure.
TAE-induced fast ion losses and transport at the Globus-M/M2 spherical tokamaks
Authors: Bakharev N. N. , Balachenkov I. M. , Chernyshev F. V. , Gusev V. K. , Iliasova M. V. , Khilkevitch E. M. , Khromov N. A. , Kiselev E. O. , Kornev V. A. , Kurskiev G. S. , Melnik A. D. , Minaev V. B. , Mironov M. I. , Miroshnikov I. V. , Petrov Yu. V. , Sakharov N. V. , Shchegolev P. B. , Shevelev A. E. , Skrekel O. M. , Telnova A. Yu. , Tokarev V. A. , Tukhmeneva E. A. , Varfolomeev V. I. , Yashin A. Yu. , Zabrodsky V. V.
Published: July 2023

A multi-diagnostic study of the fast ion losses and redistribution during toroidal Alfvén eigenmodes at the Globus-M and Globus-M2 spherical tokamaks was performed. Mode amplitude and frequency evolution are discussed. Local energy-resolved spatial transport was examined using an active neutral particle analyzer. Losses and transport dependences on the mode amplitude were obtained. The change in the ion transport with the increase in plasma current and toroidal magnetic field is reported. The experimental data are compared with the modeling results.
Unidirectional microwave transduction with chirality selected short-wavelength magnon excitations
Authors: Li Yi , Lo Tzu-Hsiang , Lim Jinho , Pearson John E. , Divan Ralu , Zhang Wei , Welp Ulrich , Kwok Wai-Kwong , Hoffmann Axel , Novosad Valentine
Published: July 2023

Nonreciprocal magnon propagation has recently become a highly potential approach of developing chip-embedded microwave isolators for advanced information processing. However, it is challenging to achieve large nonreciprocity in miniaturized magnetic thin-film devices because of the difficulty of distinguishing propagating surface spin waves along the opposite directions when the film thickness is small. In this work, we experimentally realize unidirectional microwave transduction with sub-micrometer-wavelength propagating magnons in a yttrium iron garnet (YIG) thin-film delay line. We achieve a non-decaying isolation of 30 dB with a broad field-tunable bandpass frequency range up to 14 GHz. The large isolation is due to the selection of chiral magnetostatic surface spin waves with the Oersted field generated from the coplanar waveguide antenna. Increasing the geometry ratio between the antenna width and YIG thickness drastically reduces the nonreciprocity and introduces additional magnon transmission bands. Our results pave the way for on-chip microwave isolation and tunable delay line with short-wavelength magnonic excitations.
Spin photovoltaic effect in antiferromagnetic materials: Mechanisms, symmetry constraints, and recent progress
Authors: Xiao Rui-Chun , Jin Y. J. , Jiang Hua
Published: July 2023

Antiferromagnetic (AFM) materials possess unique properties, such as rapid dynamic response, resistance to external magnetic disturbances, and the absence of a stray field. AFM materials are important members in the field of spintronics, and generating the spin current in AFM materials is one of the vital topics for AFM spintronics. The spin photovoltaic effect (SPVE) is the spin counterpart of the bulk photovoltaic effect (BPVE), where the photocurrent is spin-polarized. This effect can generate spin current in a contactless and ultra-fast way. Recently, SPVE has garnered significant interest due to its potential application in AFM spintronics and rich physical content. In this perspective, the mechanism of SPVE, including the relationship between SPVE and BPVE, and symmetry constraints are reviewed. We also provide an overview of recent progress on SPVE in AFM materials. This perspective also offers a viewpoint on this exciting area of research.
Description of the KLL Auger–Meitner decay spectra of argon following primary and satellite core-ionized states
Authors: Pedersen Jacob , Decleva Piero , Coriani Sonia , Tenorio Bruno Nunes Cabral
Published: July 2023

The K-edge photoelectron and KLL Auger–Meitner decay spectra of Argon have been investigated computationally at the restricted active space perturbation theory to the second order level using biorthonormally transformed orbital sets. Binding energies were computed for the Ar 1s primary ionization, as well as for satellite states originated from shake-up and shake-off processes. Based on our calculations, the contributions of shake-up and shake-off states to the KLL Auger–Meitner spectra of Argon have been completely elucidated. Our results are compared with recent state-of-the-art experimental measurements on Argon.
Comprehensive excited state carrier dynamics of 2D selenium: One-photon and multi-photon absorption regimes
Authors: Prodhan Sayan , Chauhan Kamlesh Kumar , Singha Tara , Karmakar Manobina , Maity Nikhilesh , Nadarajan Renjith , Kumbhakar Partha , Tiwary Chandra Sekhar , Singh Abhishek Kumar , Shaijumon Manikoth M. , Datta Prasanta Kumar
Published: July 2023

Semiconductors play a critical role in optoelectronic applications, and recent research has identified group-VI 2D semiconductors as promising materials for this purpose. Here, we report the comprehensive excited state carrier dynamics of bilayer, two-dimensional (2D) selenium (Se) in one-photon and multi-photon absorption regimes using transient reflection (TR) spectroscopy. Carrier lifetime obtained from TR measurement is used to theoretically predict the photo-responsivity for 2D Se photo-detectors operating in the one-photon-absorption regime. We also calculate a giant two-photon absorption cross section of 2.9×105 GM at 750 nm hinting possible application of 2D Se as a sub-bandgap photo-detector. The carrier recombination process is dominated by surface and sub-surface defect states in one- and multi-photon absorption regimes, respectively, resulting nearly one order increased carrier lifetime in a three-photon-absorption regime (1700 ps) compared to a one-photon-absorption regime (103 ps). Femtosecond Z-scan measurement shows saturation behavior for above bandgap excitation, further indicating the possibility of 2D Se as a saturable absorber material for passive Q-switching. Our study provides comprehensive insight into the excited state carrier dynamics of bilayer 2D Se and highlights its potential as a versatile material for various linear and non-linear optoelectronic applications.
Assessing the performance of approximate density functional theory on 95 experimentally characterized Fe(II) spin crossover complexes
Authors: Vennelakanti Vyshnavi , Taylor Michael G. , Nandy Aditya , Duan Chenru , Kulik Heather J.
Published: July 2023

Spin crossover (SCO) complexes, which exhibit changes in spin state in response to external stimuli, have applications in molecular electronics and are challenging materials for computational design. We curate a dataset of 95 Fe(II) SCO complexes (SCO-95) from the Cambridge Structural Database that have available low- and high-temperature crystal structures and, in most cases, confirmed experimental spin transition temperatures (T1/2). We study these complexes using density functional theory (DFT) with 30 functionals spanning across multiple rungs of “Jacob’s ladder” to understand the effect of exchange–correlation functional on electronic and Gibbs free energies associated with spin crossover. We specifically assess the effect of varying the Hartree–Fock exchange fraction (aHF) in structures and properties within the B3LYP family of functionals. We identify three best-performing functionals, a modified version of B3LYP (aHF = 0.10), M06-L, and TPSSh, that accurately predict SCO behavior for the majority of the complexes. While M06-L performs well, MN15-L, a more recently developed Minnesota functional, fails to predict SCO behavior for all complexes, which could be the result of differences in datasets used for parametrization of M06-L and MN15-L and also the increased number of parameters for MN15-L. Contrary to observations from prior studies, double-hybrids with higher aHF values are found to strongly stabilize high-spin states and therefore exhibit poor performance in predicting SCO behavior. Computationally predicted T1/2 values are consistent among the three functionals but show limited correlation to experimentally reported T1/2 values. These failures are attributed to the lack of crystal packing effects and counter-anions in the DFT calculations that would be needed to account for phenomena such as hysteresis and two-step SCO behavior. The SCO-95 set thus presents opportunities for method development, both in terms of increasing model complexity and method fidelity.
Generation of imprinted strain gradients for spintronics
Authors: Masciocchi G. , Fattouhi M. , Spetzler E. , Syskaki M.-A. , Lehndorff R. , Martinez E. , McCord J. , Lopez-Diaz L. , Kehlberger A. , Kläui M.
Published: July 2023

In this work, we propose and evaluate an inexpensive and CMOS-compatible method to locally apply strain on a Si/SiOx substrate. Due to high growth temperatures and different thermal expansion coefficients, a SiN passivation layer exerts a compressive stress when deposited on a commercial silicon wafer. Removing selected areas of the passivation layer alters the strain on the micrometer range, leading to changes in the local magnetic anisotropy of a magnetic material through magnetoelastic interactions. Using Kerr microscopy, we experimentally demonstrate how the magnetoelastic energy landscape, created by a pair of openings, enables in a magnetic nanowire the creation of pinning sites for in-plane vortex walls that propagate in a magnetic racetrack. We report substantial pinning fields up to 15 mT for device-relevant ferromagnetic materials with positive magnetostriction. We support our experimental results with finite element simulations for the induced strain, micromagnetic simulations, and 1D model calculations using the realistic strain profile to identify the depinning mechanism. All the observations above are due to the magnetoelastic energy contribution in the system, which creates local energy minima for the domain wall at the desired location. By controlling domain walls with strain, we realize the prototype of a true power-on magnetic sensor that can measure discrete magnetic fields or Oersted currents. This utilizes a technology that does not require piezoelectric substrates or high-resolution lithography, thus enabling wafer-level production.
Viscous dissipation and variable viscosity impacts on oscillatory heat and mass transfer of gravity-driven reactive flow along heated plate
Authors: Boujelbene Mohamed , El-Zahar Essam R. , Seddek Laila F. , Ullah Zia , Makinde O. D.
Published: July 2023

The species chemical reaction is an especially significant event in transient fluids. This is a crucial element that raises the temperature as a result of a noticeable rise in reaction rates. Hydrometallurgical industries and chemical engineering, such as the manufacturing of polymers and the processing of food, put a significant amount of concentration with consequences of chemical reactions on heat and mass transport. The effects of chemical reaction, reduced gravity, viscous dissipation, and viscosity on oscillatory heat and mass properties of gravity-driven reactive flow across an inclined heated plate at three positions cos30°, cos45°, and cos60° are the main objective of this work. To elaborate material quantities, the computational mathematical model is developed. The viscosity of fluid is considered as a function of temperature. The non-dimensional model is transformed into non-oscillating and oscillating parts by using Stokes factors. For the convergence of numerical outcomes, the primitive formulation is used. The graphical and numerical findings are obtained through FORTRAN language and Tecplot-360 software. It was found that the velocity of fluid increases for lower values of reaction rate but decreases for higher reaction rate. It can be seen that the significant magnitude of oscillatory heat transfer increases as the Prandtl number increases. It is also examined that amplitude of shearing stress increases at each angle as the reduced gravity increases. The prominent amplitude in the oscillating in heat and mass transfer for minimum viscosity is noted along the inclined heated plate.
Chirality reversal of magnetic solitons in chiral Cr1/3TaS2
Authors: Han Myung-Geun , Garlow Joseph , Du Kai , Cheong Sang-Wook , Zhu Yimei
Published: July 2023

Ferromagnetism in two-dimensional (2D) materials provides an ideal platform to study emergent electromagnetic phenomena in low dimensions for future spintronics. In magnetic-element intercalated transition metal dichalcogenides, topologically nontrivial spin textures, such as chiral helimagnetic spin states and chiral soliton lattices, are realized due to the chiral lattice distortions induced by intercalated magnetic ions. Consequently, the magnetic chirality is predictably determined by the sign of antisymmetric exchange interaction (or Dzyaloshinskii–Moriya interaction, DMI) vector that is coupled to the underlying crystal chirality. Here, using cryogenic Lorentz phase microscopy, we directly observed the chirality reversal behavior of the chiral soliton lattices in Cr1/3TaS2 across the structural defects. We show that a partial 1 T stacking in 2H-TaS2 locally reduces DMI, leading to magnetic chirality reversal with direct atomic resolution imaging. Our experimental results show that manipulation of stacking sequence provides a viable way to control the chirality of topologically nontrivial soliton lattices in 2D magnets.
General features of transmembrane beta barrels from a large database
Authors: Montezano Daniel , Bernstein Rebecca , Copeland Matthew M. , Slusky Joanna S. G.
Published: July 2023

Large datasets contribute new insights to subjects formerly investigated by exemplars. We used coevolution data to create a large, high-quality database of transmembrane β-barrels (TMBB). By applying simple feature detection on generated evolutionary contact maps, our method (IsItABarrel) achieves 95.88% balanced accuracy when discriminating among protein classes. Moreover, comparison with IsItABarrel revealed a high rate of false positives in previous TMBB algorithms. In addition to being more accurate than previous datasets, our database (available online) contains 1,938,936 bacterial TMBB proteins from 38 phyla, respectively, 17 and 2.2 times larger than the previous sets TMBB-DB and OMPdb. We anticipate that due to its quality and size, the database will serve as a useful resource where high-quality TMBB sequence data are required. We found that TMBBs can be divided into 11 types, three of which have not been previously reported. We find tremendous variance in proteome percentage among TMBB-containing organisms with some using 6.79% of their proteome for TMBBs and others using as little as 0.27% of their proteome. The distribution of the lengths of the TMBBs is suggestive of previously hypothesized duplication events. In addition, we find that the C-terminal β-signal varies among different classes of bacteria though its consensus sequence is LGLGYRF. However, this β-signal is only characteristic of prototypical TMBBs. The ten non-prototypical barrel types have other C-terminal motifs, and it remains to be determined if these alternative motifs facilitate TMBB insertion or perform any other signaling function.
A universal description of stochastic oscillators
Authors: Pérez-Cervera Alberto , Gutkin Boris , Thomas Peter J. , Lindner Benjamin
Published: July 2023

Many systems in physics, chemistry, and biology exhibit oscillations with a pronounced random component. Such stochastic oscillations can emerge via different mechanisms, for example, linear dynamics of a stable focus with fluctuations, limit-cycle systems perturbed by noise, or excitable systems in which random inputs lead to a train of pulses. Despite their diverse origins, the phenomenology of random oscillations can be strikingly similar. Here, we introduce a nonlinear transformation of stochastic oscillators to a complex-valued function

Q
1
*

(
x
) that greatly simplifies and unifies the mathematical description of the oscillator’s spontaneous activity, its response to an external time-dependent perturbation, and the correlation statistics of different oscillators that are weakly coupled. The function

Q
1
*

(
x
) is the eigenfunction of the Kolmogorov backward operator with the least negative (but nonvanishing) eigenvalue
λ
1
=
μ
1
+
iω
1
. The resulting power spectrum of the complex-valued function is exactly given by a Lorentz spectrum with peak frequency
ω
1
and half-width
μ
1
; its susceptibility with respect to a weak external forcing is given by a simple one-pole filter, centered around
ω
1
; and the cross-spectrum between two coupled oscillators can be easily expressed by a combination of the spontaneous power spectra of the uncoupled systems and their susceptibilities. Our approach makes qualitatively different stochastic oscillators comparable, provides simple characteristics for the coherence of the random oscillation, and gives a framework for the description of weakly coupled oscillators.
Factors that moderate global similarity in initial L3 transfer
Authors: Cabrelli Jennifer , Pichan Carrie , Ward Jessica , Rothman Jason , Serratrice Ludovica
Published: July 2023

Much of the formal linguistic research on third language (L3) acquisition has focused on transfer source
selection, with the overall finding that (global) structural similarity between the L1/L2 and L3 is the strongest predictor of
initial transfer patterns. Recently, Cabrelli and Pichan (2021) reported data from the production of underlyingly intervocalic
voiced stops in L3 Brazilian Portuguese (BP) and L3 Italian that highlight the notion that global similarity is likely moderated
by other factors. Specifically, data from heritage Spanish/English bilinguals learning L3 BP reflected reliance on
(non-facilitative, but globally more similar) Spanish, while L3 Italian data reflected greater reliance on (facilitative, but
globally less similar) English. The current study is a first step towards identifying the source(s) of the disparity, in which we
examine the roles of degree of dominance and explicit knowledge in heritage Spanish/English bilinguals. Thirty-four L3 Italian
learners completed a delayed repetition task in all three languages. We report English-like patterns that contradict the L3 BP
data and cannot be accounted for by degree of dominance or explicit knowledge. We connect these results to existing L3 transfer
accounts and the need for further consideration of linguistic and methodological variables, particularly acoustic salience in L3
input and task modality.
That Ropes Course Might Not Be the Metaphor You Think It Is
Authors: Yancey Gulley Needham
Published: July 2023

Students from a regional comprehensive rural university were completing a challenge course activity as part of a graduate course under the auspices of team building. During the “Tarzan Swing” activity, where all participants move from one location to another by swinging on a rope, the team thought long and hard about how to support members with different physical abilities and body types, accounting for diverse strengths, weaknesses, and various fears related to accomplishing the task. One team member was reluctant to participate and her colleagues immediately started offering encouragement. The facilitator and professor also joined in the support discourse. What we all failed to recognize in the moment was that a group of white peers (fellow students), at the encouragement of two white men in power (the professor and facilitator), pushed a Black woman to swing from a tree on a rope with a loop on the end, in the middle of the woods in the rural American South.

Information

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Enhanced adsorption films of dendrimers on mild steel for super protection
Authors: Zhong Minghui , Shi Yueting , Gao Fang , Li Hongru
Published: July 2023

This study employed metronidazole skeletons based on the target branched molecules (TBMs) for achieving efficient anti-corrosion of mild steel in HCl solution. In contrast, the reference linear molecules (RLMs) carrying a single metronidazole framework were also made. The excellent corrosion resistance performance of the target dendrimers for mild steel electrodes in HCl solution was demonstrated. It is shown that the TBMs displayed a superior anti-corrosion effect for mild steel over RLMs in HCl medium at 298 K (at 0.15 mol/L, TBM1, 97.70% versus RLM1, 90.89%). It is shown that the standard Gibbs free energy changes of the adsorption of the TBMs on mild steel surface are below −33 kJ/mol (TBM1, −34.58 kJ/mol), thus an enhanced adsorption film was formed.
IL-6 selectively suppresses cDC1 specification via C/EBPβ
Authors: Kim Sunkyung , Chen Jing , Jo Suin , Ou Feiya , Ferris Stephen T. , Liu Tian-Tian , Ohara Ray A. , Anderson David A. , Wu Renee , Chen Michael Y. , Gillanders William E. , Gillanders William E. , Murphy Theresa L. , Murphy Kenneth M.
Published: July 2023

Cytokines produced in association with tumors can impair antitumor immune responses by reducing the abundance of type 1 conventional dendritic cells (cDC1), but the mechanism remains unclear. Here, we show that tumor-derived IL-6 generally reduces cDC development but selectively impairs cDC1 development in both murine and human systems through the induction of C/EBPβ in the common dendritic cell progenitor (CDP). C/EBPβ and NFIL3 compete for binding to sites in the Zeb2 −165 kb enhancer and support or repress Zeb2 expression, respectively. At homeostasis, pre-cDC1 specification occurs upon Nfil3 induction and consequent Zeb2 suppression. However, IL-6 strongly induces C/EBPβ expression in CDPs. Importantly, the ability of IL-6 to impair cDC development is dependent on the presence of C/EBPβ binding sites in the Zeb2 −165 kb enhancer, as this effect is lost in Δ1+2+3 mutant mice in which these binding sites are mutated. These results explain how tumor-associated IL-6 suppresses cDC1 development and suggest therapeutic approaches preventing abnormal C/EBPβ induction in CDPs may help reestablish cDC1 development to enhance antitumor immunity.
A combination of Kohn-Vogelius and DDM methods for a geometrical inverse problem
Authors: Chaabane Slim , Haddar Houssem , Jerbi Rahma
Published: July 2023

We consider the inverse geometrical problem of identifying the discontinuity curve of an electrical conductivity from boundary measurements. This standard inverse problem is used as a model to introduce and study a combined inversion algorithm coupling a gradient descent on the Kohn-Vogelius cost functional with a domain decomposition method that includes the unknown curve in the domain partitioning. We prove the local convergence of the method in a simplified case and numerically show its efficiency for some two dimensional experiments.
Near-IR unidirectional absorption in a tunable asymmetric one-dimensional photonic crystal with VO2 defect layers
Authors: Chen Han , Xie Qing , Wang Han
Published: July 2023

In this paper, a dynamically modulated Near-IR asymmetric composite photonic crystal (PC) is proposed, which constitutes by a one-dimensional PC (1-D PC) with vanadium dioxide (VO2) phase transition defect layers. By combining asymmetric composite PC with VO2 phase material, which will undergo the semiconductor-metal transition (SMT) under thermal stimulation, to realize the controllable unidirectional multi-channel absorber under temperature control. Based on a relatively simple 1-D stacked thin film model, the model is investigated and optimized in terms of the structure, number of periods, and the thickness of defect layers, with the result of 20 nm for VO2 defect layers and seven circles for the post-defect period. By using the pre-defect period number of 3, an average absorbance of 0.19 can be achieved when VO2 is in the semiconductor phase at low temperature. With the rise in temperature, VO2 transitions to metal phase, where the structure absorption reaches 0.99. In addition, changing the per-defect period number to 5, the average absorption at semiconductor and metal VO2 is 0.73 and 0.10, respectively. The differential absorption around the SMT enables the tunability of single photonic devices. During the simulation, the effects of electric field and incidence angle on the structure are also analyzed. Meanwhile, the Bruggeman approximation effective medium theory is introduced in this work, and the changes of the absorption during the phase transition from semiconductor to metal in the VO2 defect layers are also given. These characteristics are applicable to controllable multispectral absorbers, infrared detectors, limiter, and optical switchers.
A hybrid energy harvester with dual-frequency-up-conversion mechanism for ultra-low frequency rotational motion under 1.5 Hz
Authors: Li Jian , Han Xinxin , Rui Xiaobo , Li Hang , Zhang Yu , Zhang Wen , Zeng Zhoumo
Published: July 2023

This paper proposes a hybrid energy harvester (HEH) based on dual-frequency-up-conversion mechanism, which is suitable for ultra-low frequency rotation. This mechanism takes full advantage of the periodic excitation provided by gravity to achieve two harvesting responses in one cycle. HEH consists of the piezoelectric energy harvester (PEH) and electromagnetic energy harvester. The magnet component achieves frequency up-conversion of PEH by impact, and also induces electrical energy from the coil, thus coupling two parts together to form continuous energy harvesting. The electromechanical coupling model of HEH is established, and the characteristics are in-depth analyzed via experiments and simulations. PEH can attain a bandwidth of 1.4 Hz with an open-circuit output voltage above 5.6 V, which indicates the frequency up-conversion helps the piezoelectric cantilevers to break through the resonance limit and obtain the higher output. HEH can combine the advantages of two energy harvesting parts, obtaining the maximum power of 6.598 mW under 1.5 Hz. The results show that the dual-frequency-up-conversion mechanism greatly improves the efficiency of energy conversion and HEH has the ability to power low-power sensors at ultra-low frequencies.
Characterization of mechanical equivalent properties for node enhanced graded lattice structure
Authors: Wu Bin , Sun Feifan , Wang Lizhe , Chen Min , Lu Yi , Jiang Di
Published: July 2023

Considering the stress concentration at the rod connection of traditional body-centered cubic (BCC) lattice structure, a node enhanced BCC (NBCC) lattice structure was proposed. In recent years, graded lattice structure has gradually attracted attention due to their unique mechanical properties. In this paper, two different graded NBCC lattice structures were designed and their static mechanical properties were evaluated through quasi-static compression experiments and simulations. Moreover, homogenization theory was applied to calculate the equivalent modulus of lattice structure. This method was extended from uniform lattice structure to graded lattice structure by improving the application of periodic boundary conditions. The obtained results were in good agreement with the experimental and simulation data. The quasi-static compression tests demonstrated that NBCC can effectively reduce the stress concentration and improve the load-bearing capacity about 25% compared to BCC. The graded lattice structures exhibit varying mechanical properties depending on their design and present better mechanical performance in the anisotropic direction. Finally, the relative relationship between the equivalent elastic modulus and the equivalent shear modulus in the lattice structure was studied. The prediction formula for equivalent shear modulus was extended based on the Gibson-Ashby formula.
Self-assembled ratiometric sensor for specific detection of hypoxia in living cells based on lanthanide-doped upconversion nanoparticles and gold nanoparticles
Authors: Zhang Xuetao , Shu Wenhao , Cheng Manxiao , Wang Linna , Ran Xiang
Published: July 2023

We describes the development of a self-assembled nanoprobe for ratiometric sensing of hypoxia in living cells. The probe, UC-AuNPs, is composed of azo-functionalized upconversion nanoparticles (azo-UCNPs) and gold nanoparticles functionalized with β-cyclodextrin (CD-AuNPs). Under hypoxic conditions, reductases reduce azo derivatives on the UCNPs, leading to detachment of the CD-AuNPs and subsequent fluorescence recovery of the green emission. The ratiometric measurement incorporated into the strategy reduces the impact of external factors and improves sensitivity of the probe. The use of NIR excitation effectively minimizes interference from strong luminescence backgrounds in biosystems. The UC-AuNPs nanoprobe is able to effectively sense and monitor hypoxia conditions in living cells and has the potential to distinguish hypoxia-related diseases from healthy tissue, making it a valuable tool for early clinical diagnosis.
Fast dose calculation in x-ray guided interventions by using deep learning
Authors: Villa Mateo , Nasr Bahaa , Benoit Didier , Padoy Nicolas , Visvikis Dimitris , Bert Julien
Published: July 2023

Objective. Patient dose estimation in x-ray-guided interventions is essential to prevent radiation-induced biological side effects. Current dose monitoring systems estimate the skin dose based in dose metrics such as the reference air kerma. However, these approximations do not take into account the exact patient morphology and organs composition. Furthermore, accurate organ dose estimation has not been proposed for these procedures. Monte Carlo simulation can accurately estimate the dose by recreating the irradiation process generated during the x-ray imaging, but at a high computation time, limiting an intra-operative application. This work presents a fast deep convolutional neural network trained with MC simulations for patient dose estimation during x-ray-guided interventions. Approach. We introduced a modified 3D U-Net that utilizes a patient’s CT scan and the numerical values of imaging settings as input to produce a Monte Carlo dose map. To create a dataset of dose maps, we simulated the x-ray irradiation process for the abdominal region using a publicly available dataset of 82 patient CT scans. The simulation involved varying the angulation, position, and tube voltage of the x-ray source for each scan. We additionally conducted a clinical study during endovascular abdominal aortic repairs to validate the reliability of our Monte Carlo simulation dose maps. Dose measurements were taken at four specific anatomical points on the skin and compared to the corresponding simulated doses. The proposed network was trained using a 4-fold cross-validation approach with 65 patients, and evaluating the performance on the remaining 17 patients during testing. Main results. The clinical validation demonstrated a average error within the anatomical points of 5.1%. The network yielded test errors of 11.5 ± 4.6% and 6.2 ± 1.5% for peak and average skin doses, respectively. Furthermore, the mean errors for the abdominal region and pancreas doses were 5.0 ± 1.4% and 13.1 ± 2.7%, respectively. Significance. Our network can accurately predict a personalized 3D dose map considering the current imaging settings. A short computation time was achieved, making our approach a potential solution for dose monitoring and reporting commercial systems.
Experimental evidence of various mode numbers of azimuthal waves in an
E×B
Penning source for semiconductor processing
Authors: Cheon Cheongbin , Choi Jinyoung , Koo John Bon-Woong , Kim June Young
Published: July 2023

This study presents the first experimental evidence for the existence of various mode numbers of azimuthal waves in an E × B Penning source used for semiconductor processing. To accurately measure these mode numbers, we utilized an eight-tip probe array aligned in an azimuthal direction to acquire spatiotemporal signals and applied the Beall analysis to obtain the dispersion relations. We combined seven dispersion relations obtained from distinct probe pairs to derive a single dispersion relation. This method allowed us to enhance the accuracy and reliability of the measurements. Our results show that the amplitude of the fast Fourier transformation (FFT) undergoes significant changes as the discharge voltage and magnetic field strength are varied. We observed that a distinguishable peak seen at higher discharge voltage is divided into a wide range of dominant peaks up to eight when the discharge voltage is decreased. The dispersion relation reveals that the phase velocity of each mode is proportional to the frequency. As the magnetic field strength increases, the amplitude of the FFT rapidly decreases except for a dominant peak corresponding to mode number 3. Ultimately, the low azimuthal mode dominates the azimuthal oscillation. Moreover, the radial profile of the FFT results shows that the frequencies of modes are nearly constant along the radial direction and have a maximum spectral magnitude at the periphery of the plasma core. Notably, as the amplitude of the modes increased, the maximum amplitude transitioned away from the core region. The findings from experiment with the multi-arrayed probe suggest the presence of a characteristics eigenmode in the E × B Penning source. This eigenmode appears to be a fundamental and pervasive feature of the system, spanning a range of mode numbers from low to high.
High-energy electron local injection in top-gated metallic superconductor switch
Authors: Du Hongmei , Xu Zuyu , Wei Zihan , Li Dingding , Chen Shixian , Tian Wanghao , Zhang Ping , Lyu Yang-Yang , Sun Hancong , Wang Yong-Lei , Wang Huabing , Wu Peiheng
Published: July 2023

The gate-tunable superconductivity in metallic superconductors has recently attracted significant attention due to its rich physics and potential applications in next-generation superconducting electronics. Although the operating principles of these devices have been attributed to the small leakage currents of high-energy electrons in recent experiments, the generated phonons can spread over considerable distances in the substrate, which may limit their further applications. Here, we utilize a top gate structure with monocrystalline h-BN as a gate dielectric and demonstrate the gate-adjustable supercurrent in a metallic Nb microbridge. The gate current of the devices perfectly follows the Fowler–Nordheim law of field emission, indicating that the injection of high-energy electrons presumably causes the suppression of the supercurrent. Our devices reduce the distance between the gate and the microbridge to a few nanometers or less, significantly minimizing the generated phonons’ spreading distance and power dissipation in the substrate or surrounding environment. These observations demonstrate that top-gated metallic superconducting switches with local electron injection can improve the device integration density, providing us with more versatile and practical opportunities to explore superconducting circuit architecture.
Correlation between microstructure and superconducting properties of MgB2 bulk samples with Mg addition and Mg/hBN co-additions
Authors: Gao Zilin , Grovenor Chris R M , Speller Susannah C
Published: July 2023

The microstructure of polycrystalline MgB2 has a strong influence on the current carrying ability, with grain boundaries and non-superconducting nanoparticles acting as good flux pinning centres which improve the local (intrinsic) critical current density (J
c) of the material, whereas porosity and poor connectivity between grains or particles adversely affect macroscopic current transport. Previous studies have found that hexagonal boron nitride (hBN) doping improves intrinsic J
c by introducing nanoscale flux pinning centres, and Mg doping improves extrinsic J
c by liquid-assisted sintering. Here we investigate the effect of co-doping with 5 wt.% Mg and 1 wt.% hBN with the aim of combining the improved intrinsic and extrinsic properties in bulk MgB2 samples fabricated using field assisted sintering. Additionally, the influence of ball milling and processing temperatures on MgB2 samples with only Mg additions is reported. By correlating microstructure with superconducting properties, we show that the presence of Mg liquid during processing of Mg-doped samples accelerates the reaction between BN and MgB2, forming an impurity phase, MgNB9, the presence of which is detrimental to superconducting performance. Nevertheless, we have achieved a considerable improvement in performance of samples doped only with Mg by increasing the sintering temperature.
Lie symmetry analysis, conservation laws and exact solutions for variable-coefficients (2+1)-dimensional dissipative long-wave system
Authors: Yang Jiajia , Jin Meng , Xin Xiangpeng
Published: July 2023

The Lie symmetry analysis, optimal system, exact solutions and conservation laws of the (2+1)-dimensional variable-coefficients dissipative long-wave (vcDLW) system are introduced in this paper. Lie symmetry analysis method is used to obtain the vector field firstly. And the Olver

′
s

method is used to obtain the optimal system of one-dimensional subalgebras of the equations. Based on the optimal system, the equations are similarly reduced. Some representative equations are selected from the equations obtained after similarly reduction, and then the

G
′

/

G

−

expansion method is applied to these equations, so that some new exact solutions of the (2+1)-dimensional vcDLW equations can be obtained. Finally, we study the conservation laws of the system.
Switchable metasurface with double phase distributions for wavefront manipulation
Authors: Niu Junhao , Li Chunhui , Yao Qianyu , Mo Wei , Zhu Aijun
Published: July 2023

We designed a switchable metasurface for wavefront manipulation by employing vanadium dioxide (VO2), which can convert the circular polarized wave to its cross-polarized wave. With the change of conductivity of VO2 at different temperatures, the metasurface can exhibit two different phase distributions at the same targeted frequency. The two phase distributions can be easily attained by rotating two rings of the unit elements. Next, based on the metasurface, we designed focal length switchable metalens and generated vortex beam carrying OAM in different modes controlled by temperature. Different from the traditional multifunctional integrated metasurfaces, the designed metasurface has a dynamic tunable feature, providing great flexibility in wavefront manipulation.
Tunneling induced swapping of orbital angular momentum in a quantum dot molecule
Authors: Al-Hawary S I S , R Kadhum Wesam , Abdu Musad Saleh E , Yacin Y , Adnan Abdullah E , Qasim M T , Abdullaeva B , Sapaev I B , Abdulfadhil Gatea M , Alsalamy A
Published: July 2023

In this paper, we have examined the effectiveness exchange of optical vorticity via three-wave mixing (TWM) technique in a four-level quantum dot (QD) molecule by means of the electron tunneling effect. Our analytical analysis demonstrates that the TWM procedure can result in the production of a new weak signal beam that may be absorbed or amplified within the QD molecule. We have taken into account the electron tunneling as well as the relative phase of the applied lights to assess the absorption and dispersion characteristics of the newly generated light. We have discovered that the slow light propagation and signal amplification can be achieved. Our results show that the exchange of the orbital angular momentum of light can transfer from coupling optical vortex light to the new generated light in high efficiency.