bluuebunny/crossref_metadata_2025 huggingface dataset:
Effectiveness of Computerized Auditory Training on Speech Perception in Children With Hearing Loss: A Systematic Review
Authors: Silva Joice de Moura , Silva Bárbara Cristiane Sordi , Lopes Natália Barreto Frederigue , Jacob Regina Tangerino de Souza , Moret Adriane Lima Mortari
Published: November 2023

Purpose:

The purpose of this study was to investigate the effectiveness of using computerized auditory training in the auditory perception of speech in children who use electronic devices through a systematic review of the literature.

Method:

This is a systematic review based on the elaboration of the following guiding question: In hearing-impaired children who use electronic devices, how effective is the use of computerized auditory training in the auditory perception of speech? The Cochrane Library, Embase, LILACS, PubMed, Web of Science, and Scopus databases and gray literature (Google Scholar and ProQuest) were consulted.

Results:

Nine hundred and eighteen records were identified, with additional two studies in the citation search, totaling 920 studies. After excluding the 184 duplicate references, using the Rayyan platform, the titles and abstracts were screened (
n
= 736), with 20 studies selected and considered for full reading. Six of the 20 studies were included in the systematic review of the literature.

Conclusions:

Positive and beneficial results regarding computerized auditory training are evidenced, which describe and discuss the proof of the effectiveness of the positive effects on the auditory perception of speech in children using hearing aids and cochlear implants with regard to auditory detection skills, discrimination, recognition, and auditory memory. The positive results are inspiring for the continuity and expansion of studies that further investigate the use of computerized auditory training with contemporary technologies and have an impact on the improvement of access to specialized intervention.
Exploring the dust grain size and polarization mechanism in the hot and massive Class 0 disk IRAS 16293-2422 B
Authors: Zamponi Joaquin , Maureira María José , Liu Hauyu Baobab , Zhao Bo , Segura-Cox Dominique , Ko Chia-Lin , Caselli Paola
Published: November 2023

Context. Multiwavelength dust continuum and polarization observations arising from self-scattering have been used to investigate grain sizes in young disks. However, the likelihood of self-scattering being the polarization mechanism in embedded disks decreases for very highly optically thick disks and makes us reconsider some of the size constraints from polarization, particularly for younger and more massive disks. The 1.3 mm polarized emission detected toward the hot (≳400 K) Class 0 disk IRAS 16293-2422 B has been attributed to self-scattering, with predictions of bare grain sizes between 200 and 2000 µm.

Aims. We aim to investigate the effects of changing the maximum grain sizes in the resultant continuum and continuum polarization fractions from self-scattering for a hot and massive Class 0 disk extracted from numerical simulations of prestellar core collapse and to compare them with IRAS 16293 B observations.

Methods. We compared new and archival dust continuum and polarization observations at high resolution between 1.3 and 18 mm to a set of synthetic models. We developed a new publicly available tool to automate this process called Synthesizer. This tool is an easy-to-use program for generating synthetic observations from numerical simulations.

Results. Optical depths are in the range of 130 to 2 from 1.3 to 18 mm, respectively. Predictions of significant grain growth populations, including amax = 1000 µm, are comparable to the observations from IRAS 16293 B at all observed wavelengths. The polarization fraction produced by self-scattering reaches a maximum of approximately 0.1% at 1.3 mm for a maximum grain size of 100 µm, which is an order of magnitude lower than the grain size observed toward IRAS 16293 B.

Conclusions. From comparison of the Stokes I fluxes, we conclude that significant grain growth could be present in the young Class 0 disk IRAS 16293 B, particularly in the inner hot region (< 10 au, T > 300 K) where refractory organics evaporate. The polarization produced by self-scattering in our model is not high enough to explain the observations at 1.3 and 7 mm, and such effects as dichroic extinction and polarization reversal of elongated aligned grains remain other possible but untested scenarios.
Classification and parameterization of a large Gaia sample of white dwarfs using XP spectra
Authors: Vincent O. , Barstow M. A. , Jordan S. , Mander C. , Bergeron P. , Dufour P.
Published: November 2023

Context. The latest Gaia data release in July 2022, DR3, in addition to the refinement of the astrometric and photometric parameters from DR2, added a number of important data products to those available in earlier releases, including radial velocity data, information on stellar multiplicity, and XP spectra of a selected sample of stars. Gaia has proved to be an important search tool for white dwarf stars, which are readily identifiable from their absolute G magnitudes as low luminosity objects in the Hertzsprung–Russell (H–R) diagram. Each data release has yielded large catalogs of white dwarfs, containing several hundred thousand objects, far in excess of the numbers known from all previous surveys (∼40 000). While the normal Gaia photometry (G, GBP, and GRP bands) and astrometry can be used to identify white dwarfs with high confidence, it is much more difficult to parameterize the stars and determine the white dwarf spectral type from this information alone. Observing all stars in these catalogs with follow-up spectroscopy and photometry is also a huge logistical challenge with current facilities.

Aims. The availability of the XP spectra and synthetic photometry presents an opportunity for a more detailed spectral classification and measurement of the effective temperature and surface gravity of Gaia white dwarfs.

Methods. A magnitude limit of G < 17.6 was applied to the routine production of XP spectra for Gaia sources, which would have excluded most white dwarfs. Therefore, we created a catalog of 100 000 high-quality white dwarf identifications for which XP spectra were processed, with a magnitude limit of G < 20.5. Synthetic photometry was computed for all these stars, from the XP spectra, in Johnson, SDSS, and J-PAS, published as the Gaia Synthetic Photometry Catalog – White Dwarfs (GSPC-WD). We took this catalog and applied machine learning techniques to provide a classification of all the stars from the XP spectra. We have then applied an automated spectral fitting program, with χ-squared minimization, to measure their physical parameters (effective temperature and log g) from which we could estimate the white dwarf masses and radii.

Results. We present the results of this work, demonstrating the power of being able to classify and parameterize such a large sample of ≈100 000 stars. We describe what we can learn about the white dwarf population from this dataset. We also explored the uncertainties in the process and the limitations of the dataset.
Rhodium-Catalyzed Direct Vinylene Annulation of 2-Aryloxazolines and Cascade Ring-Opening Using a Vinyl Selenone
Authors: Nishii Yuji , Miura Masahiro , Kitano Junya , Hirano Koji
Published: November 2023

Over the past two decades, transition-metal-catalyzed C–H activation and the subsequent oxidative cyclization with alkynes or their surrogates has emerged as a powerful synthetic tool for fused heteroaromatics. We report a Rh(III)-catalyzed annulation and ring-opening cascade reaction with 2-aryloxazolines. By utilizing a vinyl selenone as an oxidizing acetylene surrogate, the target three-component coupling products were obtained in high yields without using a stoichiometric amount of external oxidant.
Synthesis of an Alternating Polycation with the Dense 1,2,3-Triazole Backbone
Authors: Hashidzume Akihito , Omae Tomoki , Nakahata Masaki , Kamon Yuri
Published: November 2023

Polycations are an important class of water-soluble polymers because they form polyion complexes with DNA. Thus, the synthesis of polycations with controlled monomer sequences will be of increasing importance for the formation of well-defined polyion complexes. In this study, cationic homopolymer and alternating copolymer with the dense triazole backbone were synthesized by copper(I)-catalyzed azide–alkyne cycloaddition polymerization. The polycations obtained were characterized by potentiometric and turbidimetric titrations, and by complex formation with poly(acrylic acid).
Design of Indole-Functionalized Phosphepines towards New Organic Chromophores
Authors: Ren Yi , Liu Zhaoxin
Published: November 2023

Organic chromophores emerged as diverse functional materials in the areas of organic catalysis, toxic materials sensing, bio-imaging, and organic electronic devices. With rich chemical and electronic structures, main-group elements have been extensively implanted in organic chromophores to fine-tune the chemical/electronic structures and optoelectronic properties. In this Synpact article, we present a concise overview of the development of phosphorus (P)-containing organic chromophores, further highlighting our recent contributions in the field. A new aspect of combining the P element with the indole moiety was pursued to construct a new series of seven-membered P-organic chromophores; namely, indole-functionalized phosphepines. The new combination endowed the system with rich chemical and electronic structures, for which intriguing photophysical properties were consequently revealed. The combination provided an efficient synthetic protocol to access new P-heterocycles and also offered a new strategy to design functional organic chromophores.
The Cyanopyridine–Aminothiol Click Reaction: Expanding Horizons in Chemical Biology
Authors: Nitsche Christoph
Published: November 2023

Bioorthogonal reactions hold significant promise for applications in chemical biology. Despite their potential, nitriles have often been overlooked as reactive functional groups for selective bioconjugation. The condensation reaction between cyanopyridines and 1,2-aminothiols stands out as a particularly favorable nitrile modification strategy that proceeds under biocompatible conditions. Cyanopyridines can be seamlessly incorporated into peptides and proteins through both chemical and biotechnological approaches. Similarly, the selective integration of 1,2-aminothiols into peptides and proteins is achievable, leveraging the uniquely reactive N-terminal cysteine functional group.

1 Introduction

2 The Biocompatible Condensation Reaction

3 Peptide Macrocyclisation

4 Orthogonality to Cysteine

5 Combination with Genetic Encoding

6 Conclusion
Synthesis of the Hexasaccharide Repeating Unit Corresponding to the Cell Wall O-Antigen of Providencia alcalifaciens O9:H8 Strain
Authors: Misra Anup Kumar , Rana Abhijit
Published: November 2023

A straightforward synthesis of the hexasaccharide repeating unit of the O-specific polysaccharide of Providencia alcalifaciens O9:H8 strain was achieved in very good yield by applying a stereo- and regioselective [4+2] block glycosylation strategy. The tetrasaccharide acceptor and disaccharide donor were synthesized by sequential stereo- and regioselective glycosylations. Thioglycoside and glycosyl trichloroacetimidate derivatives were used as glycosyl donors in the synthetic strategy. The glycosylation steps were high-yielding and gave satisfactory stereochemical outcomes.
Interaction in prevention: a general theory and an application to COVID-19 pandemic
Authors: Battiston Pietro , Menegatti Mario
Published: November 2023

We study a model introducing interactions in agents’ prevention effort, including both the case where agents’ efforts reinforce each others and the case where they are conflicting. We characterize best response functions, distinguishing the case of strategic complementarity and the case of strategic substitutability, and determine the features of Nash equilibria in both cases. We find conditions for under- and over-provision of prevention compared to its socially optimal level. Finally, we specialize our model to describe the risk of COVID-19 infection. We show the features of contagion are consistent with the existence of asymmetric equilibria and we provide arguments in favor of policy interventions, such as making face masks mandatory, despite the possibility that they reduce some agents’ effort.
Tax holidays and profit-repatriation rates for FDI firms: the case of the Czech Republic
Authors: Vu Duong Hoang , Pavelková Drahomíra , Damborský Milan
Published: November 2023

The Czech Republic has been a promising destination for foreign investors due to its locational advantages and tax-incentive policy. However, the profit-repatriation rate in the country is extremely high, which results in less capital being available for development. This paper studies the differences in profit-repatriation rates among FDI (foreign direct investment) firms in the Czech Republic after the appearance of tax-holiday incentives from 2008 to 2019. The precondition is to find the determinants of the repatriation rate of FDI firms, and the results show that the profit repatriation rate of FDI firms is positively affected by firm size and the liquidity of firms and negatively affected by investment opportunities and leverage. The paper divides FDI firms into several groups and examines the differences in repatriation rates between them before revealing the determinants of these differences. Firstly, there is no difference in profit repatriation between FDI firms with tax incentives and those without tax incentives. Next, we divide the FDI firms with tax incentives into two groups: those who still enjoy the tax incentives and those who no longer enjoy the tax incentives. The FDI firms with tax incentives that are in the tax-incentive period repatriate less than FDI firms with tax incentives that are not in the tax period any longer. The difference stems from the endowment effect, and three determinants that can reduce the repatriation rate of FDI firms that are no longer in the tax period are investment opportunities, leverage, and firm size.
A pair of non-isometric potentials with the same semiclassical invariants
Authors: West Matthew
Published: November 2023

We show that there exist pairs of non-isometric potentials for the 1D semiclassical Schrödinger operator whose spectra agree up to O(h∞), yet their corresponding eigenvalues differ no less than exponentially. This result was conjectured in the work of Guillemin and Hezari [Inverse Probl. 28, 045009 (2012)], where they prove a very similar result, yet cannot remove the possibility of a subsequence hk → 0 where the ground state eigenvalues may agree.
Liquid-metal/NdFeB/Ni composites for high wettability, patternable, stretchable electronic wire
Authors: Zhu Zhifang , Zhao Ran , Ye Bingliang , Wang Huan
Published: November 2023

Room-temperature liquid-metal (LM) has high conductivity, which is an ideal material for manufacturing stretchable electronic wires. However, its high surface tension and fluidity make it extremely difficult to adhere to or encapsulate on flexible substrates. This work developed LM/NdFeB/Ni composites for stretchable electronic wires. The composites were composed of Ga68.5In21.5Sn10 (with a melting point at −19 °C) alloys, Nd2Fe14B (5 μm), and Ni (50–500 nm) microparticles. The SEM and EDS results showed the porous structure of the composites. Ni particles were added to improve the magnetic properties of LM/NdFeB composites, as well as the porous structure composed of magnetized NdFeB particles. Thereby the structure exhibited a heightened capacity for LM locking. Test results indicate that the liquid metal wires have good wettability and adhesion on different surfaces and could be manufactured using different patterning methods. Moreover, its anti-extrusion and anti-leakage characteristics were suitable for constructing stretchable circuits in open channels or on flat surfaces. The proposed LM/NdFeB/Ni composites are expected to manufacture low-cost, patternable, and anti-extrusion stretchable electronic wires.
The critical role of temperature-dependent mobilities in determining the open-circuit voltage of bulk-heterojunction organic solar cells
Authors: Tang Yahui , Lakhwani Girish , McNeill Christopher R.
Published: November 2023

While solution-processed bulk-heterojunction organic solar cells (OSCs) continue to attract attention as their efficiencies approach 20%, the physical origin of the non-radiative energy loss in OSCs remains under debate. Understanding the temperature dependence of open-circuit voltage (VOC) is thus important because it provides unique insights into the origin of energy loss. Herein, we simulate the VOC vs T relation of PTB7-Th:PC71BM bulk-heterojunction OSCs within the range of 160–295 K by incorporating experimentally measured temperature-dependent mobilities into the drift-diffusion model, assuming bimolecular recombination as the primary recombination mechanism. Significantly, we find that the temperature dependence of VOC can only be correctly reproduced by the model when the temperature dependence of the carrier mobilities is taken into account. The effect of the Langevin reduction coefficient on the temperature dependence of VOC is also investigated.
Efficiency enhancement in a lensed nanowire solar cell
Authors: Bochicchio Emanuele , Koolen Philemon A. L. M. , Korzun Ksenia , Quiroz Monnens Simon V. , van Gorkom Bas , Rivas Jaime Gómez , Haverkort Jos E. M.
Published: November 2023

We investigate microlenses that selectively focus the light on only a small fraction of all nanowires within an arrayed InP nanowire solar cell. The nano-concentration improves both the short-circuit current (Jsc) and the open-circuit voltage (Voc) of the solar cell. For this purpose, polymethyl methacrylate microlenses with 6 μm diameter were randomly positioned on top of an arrayed nanowire solar cell with 500 nm pitch. The microlenses were fabricated by first patterning cylindrical micropillars, which were subsequently shaped as lenses by using a thermal reflow process. The quality of the microlenses was experimentally assessed by Fourier microscopy showing strong collimation of the emitted photoluminescence. By analyzing the slope of the integrated photoluminescence vs excitation density, we deduce a substantial enhancement of the external radiative efficiency of a nanowire array by adding microlenses. The enhanced radiative efficiency of the lensed nanowire array results in a clear enhancement of the open-circuit voltage for a subset of our solar cells. The microlenses finally also allow to increase the short-circuit current of our relatively short nanowires, providing a route to significantly reduce the amount of expensive semiconductor material.
Realization of dual-functional resistive switching characteristics in Ag−In−Zn−S/sericin peptide-based memristive device
Authors: He Nan , Yan Jie , Zhang Zhining , Ye Fan , Qin Haiming , Hu Ertao , Wang Xinpeng , Chen Pu , Sheng Yang , Tong Yi , Zhang Lei , Xu Feng
Published: November 2023

Employing suitable materials and device engineering is one of the crucial methods toward the realization of multifunctional memristive devices for constructing bioinspired neuromorphic systems. In this work, dual-functional memristors composed of eco-friendly natural silk sericin, coexistently enabling the achievement of threshold switching and memory switching triggered by adjusting the compliance current value, have been fabricated with a specific two-terminal device structure: Ag/Ag−In−Zn−S/silk sericin/W. Experimentally, the as-manufactured memristors exhibit several desirable qualities, such as low switching voltage (< 0.7 V), relatively small cycle-to-cycle and device-to-device variabilities, nonvolatile multilevel storage characteristics, and rapid switching speed (40 ns). Beyond these qualities, fundamental synaptic behaviors, such as paired-pulse facilitation and spike-timing-dependent plasticity (STDP), have been mimicked. This was made possible by a filamentary mechanism based on Ag migration. The fitted time constants corresponding to the STDP potentiation and depression are about 30 ms, and the highest changes in synaptic weight for positive and negative voltage pulses are 84.4% and 61.7%, respectively. Furthermore, the typical coincidence detection task has been executed, demonstrated by simulation based on the fitted STDP's parameters of the sericin-based device. The results from this study indicate that the sericin-based memristors, as designed, have the potential to be employed in the creation of versatile neuromorphic devices for neuromorphic computing systems.
An improved algorithm for thermal compensation of synchrotron radiation optical mirrors based on Hessian matrix
Authors: Li Tong , Zhang Haipeng , Jin Limin , Zhu Wanqian , Chen Jiahua , Xue Song
Published: November 2023

The heaters-based thermal-compensated adaptive adjustment of a reflection mirror at Shanghai high repetition rate X-ray Free-Electron Laser and extreme light facility (SHINE) is presented here based on finite element analysis. The correction performance of different control algorithms [singular value decomposition and gradient descent (GD)] is analyzed and compared. This study has demonstrated that a significant control algorithm can further improve the surface shape accuracy of the mirror. After optimizing the mirror control algorithm, the calculated slope errors and height errors of the mirror are reduced to nearly less than 50 nrad rms and 0.5 nm rms, respectively. The optimization result indicates that the GD control algorithm based on the Hessian matrix exhibits superior performance and practicality compared to the control algorithm before optimization.
Research on fault diagnosis of electric submersible pump based on improved convolutional neural network with Bayesian optimization
Authors: Wan Min , Gou Meihui
Published: November 2023

A conventional intelligent fault diagnosis approach for electric submersible pumps (ESPs) is heavily dependent on manual expertise for feature extraction. Meanwhile, a conventional convolutional neural network (CNN) exhibits an excess of parameters and requires a substantial volume of training samples. In this paper, a fault diagnosis algorithm of ESPs based on a Bayesian optimization-one-dimensional convolutional neural network-support vector machine (BO-1DCNN-SVM) is proposed by combining a 1DCNN with a SVM and using the algorithm BO to tune the improved 1DCNN. First, the method uses the self-extracting feature capability of the 1DCNN to solve the problem that traditional diagnosis methods over-rely on manual experience extraction. Meanwhile, the last layer of the convolutional neural network Softmax layer is replaced by the SVM to effectively process a few sample data. The accuracy and generalization ability of the fault classification of the electric submersible pump are improved. Then, the Bayesian optimization algorithm is used to find the optimal combination of hyperparameters for the improved 1DCNN-SVM model to further improve the prediction performance of the fault diagnosis model. Finally, the experimental results achieved a classification accuracy of 96.64%, which is 5% higher than existing CNN approaches with data samples of similar scale in this paper. The proposed method also proved to be highly accurate and robust in fault diagnosis.
Wide dynamic range charge sensor operation by high-speed feedback control of radio-frequency reflectometry
Authors: Fujiwara Yoshihiro , Shinozaki Motoya , Matsumura Kazuma , Noro Kosuke , Tataka Riku , Sato Shoichi , Kumasaka Takeshi , Otsuka Tomohiro
Published: November 2023

Semiconductor quantum dots are useful for controlling and observing quantum states and can also be used as sensors for reading out quantum bits and exploring local electronic states in nanostructures. However, challenges remain for the sensor applications, such as the trade-off between sensitivity and dynamic range and the issue of instability due to external disturbances. In this study, we demonstrate proportional-integral-differential feedback control of the radio-frequency reflectometry in GaN nanodevices using a field-programmable gate array. This technique can maintain the operating point of the charge sensor with high sensitivity. The system also realizes a wide dynamic range and high sensor sensitivity through the monitoring of the feedback signal. This method has potential applications in exploring dynamics and instability of electronic and quantum states in nanostructures.
Ultrafast spin-to-charge conversion in antiferromagnetic (111)-oriented L12-Mn3Ir
Authors: Mao Huiling , Sasaki Yuta , Kobayashi Yuta , Isogami Shinji , Ono Teruo , Moriyama Takahiro , Takahashi Yukiko K. , Yamada Kihiro T.
Published: November 2023

Antiferromagnetic L12-Mn3Ir combines outstanding spin-transport properties with magnons in the terahertz (THz) frequency range. However, the THz radiation emitted by ultrafast spin-to-charge conversion via the inverse spin Hall effect remains unexplored. In this study, we measured the THz emission and transmission of a Permalloy/(111)-oriented L12-Mn3Ir multilayer by THz time-domain spectroscopy. The spin Hall angle was determined to be approximately constant at 0.035 within a frequency range of 0.3–2.2 THz, in comparison with the THz spectroscopy of a Permalloy/Pt multilayer. Our results not only demonstrate the potential of L12-Mn3Ir as a spintronic THz emitter but also provide insights into the THz spin transport properties of L12-Mn3Ir.
Control of a single-photon router via an extra cavity
Authors: Luo Yi-Ke , Yang Ya , Lu Jing , Zhou Lan
Published: November 2023

Controllable single-photon routing plays an important role in quantum networks. We investigate single-photon scattering in two one-dimensional (1D) waveguides by a three-level emitter with a cascade configuration, which is a dipole coupled to an extra cavity. The tunneling path for the transmission of a single photon is switched by whether the extra cavity contains photons. For the setup, the Autler–Townes splitting is modulated by the extra cavity, in which the transmission valley (reflection range) width is tunable in terms of the number of photons in the extra cavity. Our investigation will be beneficial to single-photon routing in quantum networks using quantifiable photon numbers in an extra cavity.
Ionic–electronic dynamics in an electrochemical gate stack toward high-speed artificial synapses
Authors: Levit Or , Ber Emanuel , Dahan Mor M. , Keller Yair , Yalon Eilam
Published: November 2023

Despite their great synaptic potential, the trade-off between programming speed and energy consumption of electrochemical random-access memory (ECRAM) devices are major hindrance to their incorporation into practical applications. In this work, we experimentally study the main limiting factor for high-speed programming of ECRAMs, the ionic current in the gate stack. We use two-terminal structures composed of LiCoO2/Li3PO4/amorphous-Si to represent the ECRAM gate stack (reservoir/electrolyte/channel). We perform electrical characterization including impedance spectroscopy (small-signal) and large-signal transient measurements across nine orders of magnitude in the time domain. We find that at the sub-microseconds range, the current is governed by the energy barrier for Li+ ions at the electrolyte interfaces. After a period of ∼1 μs, ionic migration through the ∼80 nm electrolyte layer dictates the current. At ∼50 μs, the ionic double layer at the interface is fully charged and the gate current drops by several orders of magnitude, indicating that the Li3PO4/Si interface is saturated, and the measured current is dominated by the electronic leakage component. Furthermore, we evaluate ECRAM performance under various pulse parameters. Our predictions show that an aggressively scaled (atomically thin) channel having a low carrier density of ∼1011 cm−2 can be programmed at ∼nanosecond using a gate current of ∼100 A/cm2.
Growth and characterization of sputter-deposited Ga2O3-based memristive devices
Authors: Baunthiyal Aman , Krisponeit Jon-Olaf , Schowalter Marco , Mehrtens Thorsten , Karg Alexander , Rosenauer Andreas , Eickhoff Martin , Falta Jens
Published: November 2023

In the last few years, there has been significant interest in gallium oxide devices for resistive switching technologies due to its remarkable sensitivity to oxygen. In this study, we present the growth and resistive switching of a (2¯01) oriented (75 ± 3) nmβ-Ga2O3 thin film on a Ru/Al2O3 substrate using magnetron radio frequency sputtering. The observed resistive switching was attributed to the formation and rupture of conductive filaments constituted by oxygen vacancies in the β-Ga2O3 film as confirmed by x-ray photoelectron spectroscopy and energy-dispersive x-ray spectroscopy. The electrical conduction was found to be of Ohmic nature in the low-resistance ON state, while the high-resistance OFF state was governed by the Poole–Frenkel transport mechanism. Exhibiting stable endurance cycles, long retention times, and ON/OFF ratios of up to 104, the devices can be considered as promising prototypes for future nonvolatile resistive switching random access memory with respect to both switching performance and device stability.
Effects of diffusion barriers on reaction wave stability in Co/Al reactive multilayers
Authors: Abere Michael J. , Reeves Robert V. , Sobczak Catherine , Choi Hyein , Kotula Paul G. , Adams David P.
Published: November 2023

Bimetallic, reactive multilayers are uniformly structured materials composed of alternating sputter-deposited layers that may be ignited to produce self-propagating mixing and formation reactions. These nanolaminates are most commonly used as rapid-release heat sources. The specific chemical composition at each metal/metal interface determines the rate of mass transport in a mixing and formation reaction. The inclusion of engineered diffusion barriers at each interface will not only inhibit solid-state mixing but also may impede the self-propagating reactions by introducing instabilities to wavefront morphology. This work examines the effect of adding diffusion barriers on the propagation of reaction waves in Co/Al multilayers. The Co/Al system has been shown to exhibit a reaction propagation instability that is dependent on the bilayer thickness, which allows for the occurrence of unstable modes in otherwise stable designs from the inclusion of diffusion barriers. Based on the known stability criteria in the Co/Al multilayer system, the way in which the inclusion of diffusion barriers changes a multilayer's heat of reaction, thermal conductivity, and material mixing mechanisms can be determined. These factors, in aggregate, lead to changes in the wavefront velocity and stability.
Plasma flow and instabilities in the magnetic mirror with ion recycling and neutral back-flow
Authors: Chapurin O. , Jimenez M. , Smolyakov A. , Yushmanov P. , Dettrick S.
Published: November 2023

Magnetic mirror configurations are observed in natural settings and have various applications in laboratory plasmas, such as a magnetic expander of the open mirror fusion devices. The axial plasma flow in open mirror systems is significantly influenced by atomic processes involving neutrals, such as ionization and charge-exchange collisions. A quasi-two-dimensional computational model was developed to study these effects on accelerated plasma flow in magnetic mirror configurations. This model includes an emitting wall, a quasineutral flow/acceleration region with a magnetic expander, and a recycling/absorbing wall. Implemented in a hybrid quasineutral code, the model incorporates drift-kinetic ions, fluid electrons, and fully kinetic neutral atoms with collision processes simulated using the direct simulation Monte Carlo approach. Ion recycling on the wall is accounted for using empirical methods. The model demonstrates that slow atoms with short mean free paths create a dense plasma layer near the wall, modifying the plasma potential which can lead to large-scale perturbations due to ion–ion streaming instabilities.
Modulation of wake evolution, separation, and radiated noise by a cylinder with porous media cladding
Authors: Feng Huanhuan , Chen Linfeng , Dong Yuhong
Published: November 2023

In this paper, the effects of porous media parameters on circular cylinder wake flow and radiation noise are investigated using large eddy simulations and Ffowcs Williams–Hawkings acoustic analogy. We performed three-dimensional numerical simulations for flow around the cylinder coated with a porous layer of different pores per inch in a subcritical flow regime (ReD=4.7×104) to explore the control mechanism of porous media on wake and radiation noise. The results show that the application of porous media significantly alters the separation pattern behind the cylinder and stabilizes the shear layer detached from the cylinder. The existence of porous layers leads to the transformation of chaotic and irregular vortex structures into more orderly vortices. Moreover, this study also reveals that the cylinder coated with high pore density can provide the desired noise reduction. The analysis of vortex sound theory indicates that porous media reduces the interaction area and magnitude of the positive and negative Lamb vector divergences, which is beneficial for drag reduction and noise attenuation. In addition, the comparison of sound pressure contours shows that the application of porous media does not change the radiation mode of noise, but the porous media with high pore density helps to decrease the generation of noise and intensity of the sound source.
Large eddy simulations of flow past an inclined circular cylinder: Insights into the three-dimensional effect
Authors: Li Gen , Li Wenhua , Janocha Marek Jan , Yin Guang , Ong Muk Chen
Published: November 2023

The flow past an inclined cylinder is simulated using large eddy simulations to study the three-dimensional wake flow effects on the forces on the cylinder at Re = 3900. Four inclination angles of α = 0°, 30°, 45°, and 60° are considered. The validity of the independence principle (IP) at the four investigated angles is examined. The results suggest that IP can predict the vortex shedding frequency at 0° ≤ α ≤ 60°, while it fails to predict the drag, lift, and pressure coefficients variations because the three-dimensional effect is neglected for IP. A comprehensive analysis is performed to provide insights into the three-dimensional effects on the drag and lift forces caused by α. The flow velocities, the Reynolds stress, and the spanwise characteristic length of the flow structures are discussed in detail. It is found that the recirculation length reaches its maximum at α = 45°, which results in the smallest drag coefficient and lift force amplitudes. The spanwise characteristic lengths of the vortices are similar for all cases, while spanwise traveling patterns are observed only for α > 0°. A force partitioning analysis is performed to quantify the correlations between the forces and the spanwise and cross-spanwise vortices. It reveals that for α = 30°, the drag force becomes dominated by the cross-spanwise vorticity. With the increasing α, the dominant contribution gradually changes from the cross-spanwise to the spanwise vorticity, and the cross-spanwise vorticity contribution to the drag force further becomes negative at α = 60°.
Studying the influence of cold-core mesoscale ocean eddies on sound propagation based on the parabolic equation method
Authors: Sun Xiaofang , Zhang Shisong , Nian Xunxian
Published: November 2023

Mesoscale vorticity is an important factor that affects the non-uniform horizontal and vertical distribution of hydrologic elements in the ocean. In this paper, temperature and salinity data from measured mesoscale cold-core eddies during a voyage within a certain sea area are studied, and a synchronous sound field test was conducted on the mesoscale vorticity. Based on the temperature and salinity data, the parabolic equation (PE) method was selected to predict the acoustic field, and the results were compared with the measured propagation loss data of the acoustic field to verify the accuracy and effectiveness of the PE model. The underwater sound propagation characteristics in the mesoscale cold-core eddy environment were then analyzed using the temperature and salinity data retrieved from the voyage. It was found that the convergence area of the acoustic field gradually dispersed with an increase in the depth of the sound source. In a mesoscale eddy environment, when sound waves propagate from inside to outside the eddy, the presence of a cold-core eddy causes the convergence area to shift toward the edge of the eddy, and the deviation gradually decreases with an increase in the depth of the sound source.
Ferroelectric-driven disorder inducing transition of bosonic insulator–superconductor in TiN/Hf0.5Zr0.5O2 heterojunction
Authors: Han Qilin , Kang Chaoyang , Chen Xuegang , Wang Kai , Zhang Weifeng
Published: November 2023

Unique quantum states induced by disorders can be characterized by quantum phase transitions in many-body systems. In this study, we experimentally observed a sharp resistance peak near the superconducting transition in superconductor/ferroelectric TiN/Hf0.5Zr0.5O2 heterostructures. The peak is attributed to the disorder introduced by ferroelectric fluctuations within the empirical model of metal–boson insulator–superconductor transitions. By modulating the quantum phase transitions in superconductivity and competing with the disorder through ferroelectric polarization, we provide a versatile platform for investigating the influence of ferroelectric materials on superconducting states.
Continuous-wave operation of an electron cyclotron maser formed in a mirror magnetic trap
Authors: Shalashov A. G. , Gospodchikov E. D.
Published: November 2023

Among various non-linear regimes of electron cyclotron instabilities that may be driven by a strong electron cyclotron resonance (ECR) heating in open magnetic traps, the continuous generation of a quasi-monochromatic wave, characterized by a smooth release of a free energy from a system, is especially important for applications, e.g., aimed at performance optimization of ECR ion sources. We study an universal model based on the quasilinear description of plasma–wave interactions that explains the condition of a continuous-wave regime of the cyclotron instability observed experimentally including, in particular, a strong dependence on a magnetic configuration.
Cation defect engineering of core–shell spinels nanoelectrocatalyst for enhanced oxygen evolution reaction
Authors: Wang Peng , Kannan Palanisamy , Lu Lei , Kumar Khagesh , Pan Cong , Guo Jinglong , Klie Robert , Cabana Jordi
Published: November 2023

Defect engineering is a promising approach to address the inherently low conductivity and limited number of reaction sites of manganese-based spinel oxides as electrocatalysts. However, high formation energies make it challenging to controllably generate cation defects in such spinel oxides. Herein, we report a heterogeneous core–shell electrocatalyst [Mn3O4@MnxCo3−xO4–Co2(OH)3Cl, MCIL] based on a facile cation-deficiency strategy. The addition of ionic liquid (1-butyl-3-methylimidazole hexafluorophosphate) to the reaction system can simply and quickly control the octahedral field defects in spinel MnCo2O4. The results show that the selective generation of defects in the Co(Oh) octahedral field can accelerate the OER reaction kinetics and provide excellent OER electrocatalytic performance. Specifically, the MCIL series catalysts can exhibit the lowest overpotential of 332 mV at 10 mA cm−2 and Tafel slope of 50 mV dec−1, compared with that of pristine samples [i.e., Mn3O4 (890 and 343 mV dec−1) and Mn3O4@MnCo2O4 (357 and 56 mV dec−1)]. This work highlights the importance of cation defect engineering to enhance the catalytic activity of materials.
Colorful visualization detection of near-infrared light enabled by an upconversion device with a color-tunable quantum dot light-emitting unit
Authors: Hu Yuanhong , Jiang Haohong , Chen Lixiang , Wang Ke , Wang Xiaoyu , Lei Yanlian
Published: November 2023

Color-tunable near-infrared (NIR)-to-visible upconversion devices (UCDs) that correlate the NIR power intensity with the visible emission color are highly desired and hold promise for interactive signal visualization in intelligent optoelectronic devices. In this work, solution-processed color-tunable UCDs integrating a NIR sensing photodetector unit and a color-tunable quantum dot (QD) light-emitting unit are demonstrated. We mixed the red and green QDs in a single emissive layer (EML) for multi-color emission from the UCDs, which is quite different from the previously reported work that used multiple EMLs with different colors. The image color of the resulting color-tunable UCDs can be modulated by bias voltage and driving current and shows a wide color-span range from red to green as the NIR intensity increases. Finally, we present a qualitative correlation between the incident NIR power intensity and the visible emission color, which enables colorful visualization detection of NIR light.
Separation of metric in Wick’s theorem
Authors: Tokmachev Andrey M.
Published: November 2023

In quantum chemistry, Wick’s theorem is an important tool to reduce products of fermionic creation and annihilation operators. It is especially useful in computations employing reference states. The original theorem has been generalized to tackle multiconfigurational wave functions or nonorthogonal orbitals. One particular issue of the resulting structure is that the metric and density matrices are intertwined despite their different origin. Here, an alternative, rather general tensorial formulation of Wick’s theorem is proposed. The main difference is the separation of the metric—the coefficients at normal-ordered operators become products of an n-electron density matrix element and the Pfaffian of a matrix formed by orbital overlaps. Different properties of the formalism are discussed, including the use of density cumulants, the particle–hole symmetry, and applications to transition density matrices, i.e., the case of different bra and ket reference states. The metric-separated version of Wick’s theorem provides a platform for the derivation of various quantum chemical methods, especially those complicated by non-trivial reference states and nonorthogonality issues.
Shock Hugoniot of an equiatomic high-entropy alloy NbMoTaW up to 143 GPa
Authors: Hu Yu , Wang Yishi , Yang Gang , Liu Xun , Huang Haijun
Published: November 2023

The equations of state and phase stabilities of high-entropy alloys (HEAs) under high-pressure and high-temperature conditions are of paramount importance for engineering applications. However, few reports exist on the high-pressure–temperature properties of the HfNbMoTaWV HEA system. Herein, we synthesized a NbMoTaW HEA using the vacuum arc melting method and measured its Hugoniot up to 143 GPa and ∼6200 K. A linear relationship [US = 2.61 (7) + 1.59 (5) UP] between the shock (US) and particle (UP) velocities was observed for UP > 0.7 km/s, suggesting that the NbMoTaW HEA is likely stable within the pressure–temperature range of the current study. Using the Debye–Mie–Grüneisen model and Birch–Murnaghan equation of state (EOS), we discussed the EOS of the NbMoTaW HEA. The bulk modulus (K0) and its pressure derivative (K0′) were determined to be 238 GPa and 3.3, respectively. We also found that the Hugoniot compression curve of the NbMoTaW HEA could be evaluated using the mixture rules with the Hugoniot data of the compositional elements.
Reconstruction of flow field with missing experimental data of a circular cylinder via machine learning algorithm
Authors: Aksoy Muharrem Hilmi , Goktepeli Ilker , Ispir Murat , Cakan Abdullah
Published: November 2023

In this study, artificial neural networks (ANNs) have been implemented to recover missing data from the particle image velocimetry (PIV), providing quantitative measurements of velocity fields. Due to laser reflection or lower intensity of particles in the interrogation area, the reconstruction of erroneous velocity vectors is required. Therefore, the distribution of time-averaged and normalized flow characteristics around a circular cylinder has been demonstrated as streamwise and cross-stream velocities at Re = 8000. These velocity components have been given for different regions at x/D = 0.5, x/D = 1.25, x/D = 2, and y/D = 0. These stations have been chosen to estimate missing data for near-wake, mid-wake, far-wake, and symmetry regions. The missing data ratios (A*) for 0.5 ≤ x/D ≤ 2 are A* = 3.5%, 7%, and 10%. In addition, these values are A* = 4%, 8%, and 12% for y/D = 0, while A* = 7.5% for the shaded region. The increment of area positively affects the estimation results for near-wake and mid-wake regions. Moreover, the errors tend to decrease by moving away from the body. At y/D = 0, increasing the area negatively influences the prediction of the results. The mean velocity profiles of predicted and experimental data have also been compared. The missing data have been predicted with a maximum percentage error of 3.63% for horizontal stations. As a result, the ANN model has been recommended to reconstruct PIV data.
Efficient FRET process between CsPbBr3 quantum dots and RhB dye molecules by pressure regulation
Authors: Gao Yong-sheng , Xu Yan-lin , Yang Tie-shan , Wang Hong-gang , Mu Hai-feng , Tan Xiao-ming , Yang Chuan-lu , Wang Kai , Li Zhi-gang , Xu Qin-feng
Published: November 2023

Fluorescence resonance energy transfer (FRET) based on quantum dots (QDs) and dye molecules have great application potential in biochemical fields. How to achieve an efficient energy transfer process has become an important research topic. Pressure can be used to regulate the energy transfer process, but its regulation on metal halide perovskite systems is rarely reported. Herein, the efficient FRET process between CsPbBr3 QDs and Rhodamine B (RhB) molecules under high pressure is investigated. Upon compression to 1.3 GPa, the FRET rate of the CsPbBr3–RhB composite reaches 0.21 ns−1 and the FRET efficiency is improved from 12.4% to 62.4%, due to enhanced spectral overlap and shortened minimum distance between CsPbBr3 QDs and RhB molecules. This study provides a strategy for achieving efficient FRET research and further promotes the development of applications based on halide perovskite molecular systems.
A surrogate model for finite element simulation of elastic wave propagation in composite materials
Authors: Li Hong , Wang Qingfeng
Published: November 2023

Deep learning surrogate models can be employed in solid mechanics to forecast the behavior of structures subjected to various loading conditions, substantially decreasing the computational costs associated with simulations. In this letter, we have utilized convolutional neural networks and Fourier transform to predict the elastic wave output from composite bars. The microstructures of the bar are utilized as inputs to the deep learning model, while the output is the elastic wave response. The convolutional neural network learns to identify crucial input composite features and utilizes this information to predict the output elastic waves. Finally, the mean squared error of the predicted output signals is compared to the actual output signals, which was used to evaluate the model. The outcomes of this study demonstrate that the deep learning model can precisely and swiftly predict the output elastic waves of the composites, thus serving as a surrogate model for time-consuming finite element simulations.