bluuebunny/crossref_metadata_2025 huggingface dataset:
Implementation of habituation on single ferroelectric memristor
Authors: Li Xinyu , Li Guangyuan , Zhang Zhihang , Zhai Wenjing , Zheng Wenhao , Chen Liufang , Lin Lin , Zhou Xiaohui , Yan Zhibo , Liu J.-M.
Published: May 2023

As a basic form of behavioral plasticity, habituation enables organisms to adjust their behaviors in response to external stimulation and is a fundamental ability of organisms. The emulation of habituation in hardware becomes critical in highly efficient artificial neuromorphic computing. However, few devices can mimic habituation because it includes two opposite responses to the same repeated stimulus. Herein, we fabricate a device of Au/LiTaO3/Pt, which not only shows synaptic plasticity, such as long-term potentiation/depression and paired-pulse facilitation, but also demonstrates habituation behavior. In addition, the habituation characteristics, which is dependent on the intensity and frequency of stimulus, are realized on the device. The analysis of electrical transport behavior indicates that the variation in resistance states correlates with the injection/extraction of free carriers during the resistance switching and suggests that the habituation behavior originates from the evolution of conductive domain walls in LiTaO3 ferroelectric.
Controlling brightness in full color nanoprinting by all-dielectric metasurfaces
Authors: Shang Xiao , He Guicang , Li Longjie , Wang Chong , Lu Cheng , Zhang Peiwen , Niu Jiebin , Shi Lina
Published: May 2023

Structural colorations with all-dielectric metasurfaces provide a dye-free approach for integrated sub-wavelength color generation with enhanced stability and environmental friendliness. However, it remains challenging to simultaneously tailor all the elementary color functions, hue, saturation, and brightness, in a simple platform. Here, we report a generic principle to create bright-field full-color nanoprinting with brightness control by using all-dielectric metasurfaces consisting of arrays of Si elliptical nanopillars. It is demonstrated that the lower order Mie resonances in the reflection spectra redshift with the sizes of the elliptical nanopillars when the incident light polarization is fixed along the major or minor axes. By designing the structure carefully, basic colors, such as red, green, blue, and yellow, are obtained across the visible spectrum. Experimental measurements show that the fabricated colors are independent with respect to the viewing angle owing to the Mie resonance origin. Moreover, we demonstrate that, by varying the angle of either the polarizer or the analyzer, the resonant wavelengths keep invariant while the reflection intensity decreases, leading to the tuning of the brightness of colors from bright to dark without changing the hue and saturation. Our scheme provides a simple yet general approach for the full hue, saturation, brightness control of structural colors, holding great potential in diverse applications, such as anti-counterfeiting technologies, 3D displays, and information storage.
Degradation of AlGaN-based UV-C SQW LEDs analyzed by means of capacitance deep-level transient spectroscopy and numerical simulations
Authors: Piva F. , Pilati M. , Buffolo M. , Roccato N. , Susilo N. , Hauer Vidal D. , Muhin A. , Sulmoni L. , Wernicke T. , Kneissl M. , De Santi C. , Meneghesso G. , Zanoni E. , Meneghini M.
Published: May 2023

The lifetime of deep-ultraviolet light-emitting diodes (LEDs) is still limited by a number of factors, which are mainly related to semiconductor defects, and still need to be clarified. This paper improves the understanding of UV LED degradation, by presenting an analysis based on combined deep-level transient spectroscopy (C-DLTS), electro-optical characterization, and simulations, carried out before and during a constant current stress test. The original results of this paper are (i) C-DLTS measurements allowed us to identify three traps, two associated with Mg-related defects, also detected in the unaged device, and one related to point defects that were generated by the ageing procedure. (ii) Based on these results and on TCAD simulations, we explain the variation in the forward I–V by the degradation of the p-contact, due to Mg passivation. (iii) On the other hand, optical degradation is ascribed to an increase in defectiveness of the active region and surrounding areas, which led to a decrease in injection efficiency, to an increase in non-radiative recombination, and to an increase in trap-assisted tunneling processes.
Molecular dynamics simulation of mechanical response of Cu50Zr50 metallic glass under double shock loading
Authors: Rong Jiacheng , Zhu Pengzhe , Xu Yimeng
Published: May 2023

In real applications, materials are often subjected to multiple shock loadings, under which the mechanical response is rather complicated and needs in-depth studies. In this paper, molecular dynamics simulations of Cu50Zr50 metallic glass (MG) that has broad application prospects in various fields under double-shock loading have been carried out in order to uncover the deformation mechanism of MG in the dynamic process. By varying the velocity and the time interval from the first shock, we found that the double shock can lead to different phenomena such as recompaction, second spallation, uncompaction, or non-spallation. We further investigated the characteristics of these different phenomena through analyzing the damage area, stress distribution, density, and temperature in the shock processes. It was found that the void collapse caused high local stress and high temperature. We also found that the shear deformation resistance of the recompaction region cannot be recovered after recompaction through the quantitative statistics of the icosahedral clusters. Moreover, the material softening caused by high temperature in the recompaction region was the main reason for second spallation. In addition, a small second shock velocity could not induce the recompaction and a small interval time between two shocks inhibited the occurrence of the first spallation. The insights gained in this study contribute to a better understanding of the dynamic response of MGs under double-shock loadings.
Non-simple flow behavior in a polar van der Waals liquid: Structural relaxation under scrutiny
Authors: Arrese-Igor S. , Alegría A. , Colmenero J.
Published: May 2023

The non-exponential character of the structural relaxation is considered one of the hallmarks of the glassy dynamics, and in this context, the relatively narrow shape observed by dielectric techniques for polar glass formers has attracted the attention of the community for long time. This work addresses the phenomenology and role of specific non-covalent interactions in the structural relaxation of glass-forming liquids by the study of polar tributyl phosphate. We show that dipole interactions can couple to shear stress and modify the flow behavior, preventing the occurrence of the simple liquid behavior. We discuss our findings in the general framework of glassy dynamics and the role of intermolecular interactions.
Solvation of magnesium chloride dimer in water: The case of anionic and neutral clusters
Authors: Wei Zhiyou , Xu Hongguang , Xu Xiling , Feng Gang , Zheng Weijun , Li Tao
Published: May 2023

The structures of magnesium chloride dimer-water clusters, (MgCl2)2(H2O)n−/0, were investigated with size-selected anion photoelectron spectroscopy and theoretical calculations to understand the dissolution of magnesium chloride in water. The most stable structures were confirmed by comparing vertical detachment energies (VDEs) with the experimental measurements. A dramatic drop of VDE at n = 3 has been observed in the experiment, which is in accordance with the structural change of (MgCl2)2(H2O)n−. Compared to the neutral clusters, the excess electron induces two significant phenomena in (MgCl2)2(H2O)n−. First, the planar D2h geometry can be converted into a C3v structure at n = 0, making the Mg–Cl bonds easier to be broken by water molecules. More importantly, a negative charge-transfer-to-solvent process occurs after adding three water molecules (i.e., at n = 3), which leads to an obvious deviation in the evolution of the clusters. Such electron transfer behavior was noticed at n = 1 in monomer MgCl2(H2O)n−, indicating that the dimerization between two MgCl2 molecules can make the cluster more capable of binding electron. In neutral (MgCl2)2(H2O)n, this dimerization provides more sites for the added water molecules, which can stabilize the entire cluster and maintain its initial structure. Specifically, filling the coordination number to be 6 for Mg atoms can be seen as a link between structural preferences in the dissolution of the monomers, dimers, and extended bulk-state of MgCl2. This work represents an important step forward into fully understanding the solvation of MgCl2 crystals and other multivalent salt oligomers.
Multiscale electric-field imaging of polarization vortex structures in PbTiO3/SrTiO3 superlattices
Authors: Addiego Christopher , Zorn Jacob A. , Gao Wenpei , Das Sujit , Guo Jiaqi , Qu Chengqing , Zhao Liming , Martin Lane W. , Ramesh Ramamoorthy , Chen Long-Qing , Pan Xiaoqing
Published: May 2023

In ferroelectric heterostructures, the interaction between intrinsic polarization and the electric field generates a rich set of localized electrical properties. The local electric field is determined by several connected factors, including the charge distribution of individual unit cells, the interfacial electromechanical boundary conditions, and chemical composition of the interfaces. However, especially in ferroelectric perovskites, a complete description of the local electric field across micro-, nano-, and atomic-length scales is missing. Here, by applying four-dimensional scanning transmission electron microscopy (4D STEM) with multiple probe sizes matching the size of structural features, we directly image the electric field of polarization vortices in (PbTiO3)16/(SrTiO3)16 superlattices and reveal different electric field configurations corresponding to the atomic scale electronic ordering and the nanoscale boundary conditions. The separability of two different fields probed by 4D STEM offers the possibility to reveal how each contributes to the electronic properties of the film.
Cascaded mode converter for generating high-order Poincaré sphere beams of multiple different orders
Authors: Yao Junna , Jiang Xiahua , Li Xiangle , Zhang Jialang , Zhan Qiwen , Wang Anting
Published: May 2023

Structured light fields, especially high-order Poincaré sphere (HOPS) beams, are attracting increasing attention for their intriguing properties and extensive applications. Here, we demonstrate a cascaded mode converter for generating HOPS beams of different orders. The cascaded mode converter is composed of q-plates and half waveplates, which realize switchable generation of HOPS beams of multiple different orders with reliable performance. Exponential growth of the available number of HOPS beams of different orders is achieved. The local polarization state and the order of the HOPS beams can be used as two degrees of freedom to encode 2 bits of information. The proposed method makes it possible to generate multiple and ultrahigh order Poincaré sphere beams and may have potential application in communication systems.
Magnetic proximity effect in the heterostructures of topological insulators and SrRuO3
Authors: Miao Qingqing , Kang Chaoyang , Song Ye-Heng , Zhang Weifeng
Published: May 2023

Introducing magnetic order into a topological insulator via the magnetic proximity effect can break the time-reversal symmetry of the topological surface states, resulting in a variety of exotic physical phenomena that are expected to be applied in spintronic devices. However, in the topological insulator/ferromagnet heterostructures obtained so far, the interfacial hybridization is too weak and difficult to induce sufficiently strong magnetism in the topological insulator. In this work, we investigate the electrical transport properties of Bi2Te3 (Sb2Te3)/SrRuO3 heterostructures and demonstrate the presence of the magnetic proximity effect in them. The Curie temperature of Bi2Te3 (Sb2Te3)/SrRuO3 heterostructures was found to be increased by about 25 K. The coercive field was suppressed in the magnetoresistance; the Hall curves of Bi2Te3 (Sb2Te3)/SrRuO3 heterostructures exhibited different orientations and appeared non-linear behavior at high fields, and the anisotropic magnetoresistance changed from twofold rotational symmetry to quadruple symmetry. These provide direct evidence for the emergence of the magnetic proximity effect. This work will help to study the magnetic proximity effect in the topological insulators and paves the way for spintronic devices in the future.
Spoof surface plasmon polariton supported by square ring metasurface for wearable body area network
Authors: Ghaddar A. , Garnier B. , Rault F. , Lheurette É. , Burgnies L.
Published: May 2023

A metasurface consisting of a 2D periodic square lattice of metallic square ring resonators is considered for supporting spoof surface plasmon polariton (SSPP) modes. First, SSPP modes are highlighted by simulated dispersion curves. The dispersion curves are analyzed by considering hybridization of modes in either a patch or an aperture array with frequency shifts. Hybridization of modes is also supported by means of surface current and electric field mappings showing consistent symmetric and anti-symmetric fields. Second, it is shown that a dipole antenna located near the metasurface is able to generate SSPP modes. The transmission spectra between two antennas located at each extremity of the metasurface show transmission enhancements compared with propagation in free space. The transmission enhancements are shown for different locations of the antennas either facing each other or positioned in diagonal. Finally, the transmission enhancement is connected to SSPP modes by comparing the transmission spectra and the measured dispersion curves with each other. Specifically, two transmission windows measured for an embroidered metasurface are related to the cutoff frequency of the two SSPP modes supported by the metasurface as evidenced by the measured dispersion curves.
Eco-friendly cellulose wearable heaters using Korean traditional Han paper coated with graphene nanosheets via binder-free supersonic spraying
Authors: Khadka Ashwin , Kim Byeong-Yeop , Park Chanwoo , Lim Woojin , Aldalbahi Ali , Periyasami Govindasami , Joshi Bhavana , Yoon Sam S.
Published: May 2023

Transparent and nontransparent exoskeleton wearable heaters are used in automobile and aircraft deicing, oil-pipeline defrosting, smart windows, underwater protection clothing, winter sportswear, bioelectronics, personal healthcare, athletic rehabilitation, and thermotherapy applications. In this study, we introduce Korean traditional Han paper (or Hanji), which comprises eco-friendly cellulose fibers from the mulberry bark, as a substrate for nontransparent wearable heaters. Hanji consists of cellulose fibers and is highly flexible, making it suitable for low-cost roll-to-roll scalable production. Graphene flakes are readily and firmly embedded inside the fibrous structure of Hanji by the catastrophic impact inflicted by supersonic spraying. Additionally, Hanji can withstand temperatures of up to 100 °C before suffering thermal damage. The heater with the thicker graphene layer had the lowest electrical resistance and exhibited the highest heating temperature at a constant voltage level. Graphene flakes are firmly held inside the fibrous structure of Hanji, securing the material's mechanical durability. Additionally, tests at various bending radii were conducted to demonstrate the mechanical strength of the Hanji graphene heater. Graphene flakes deposited on an unyielding alumina substrate withstood temperatures of up to 280 °C, thereby facilitating the use of the substrate in high-temperature applications. Graphene-coated textiles were heated and stretched up to 50%, thus demonstrating the application of such materials in human-body thermotherapy.
Hyperfine-resolved spectra of HDS together with a global ro-vibrational analysis
Authors: Melosso Mattia , Jiang Ningjing , Gauss Jürgen , Puzzarini Cristina
Published: May 2023

Despite their chemical simplicity, the spectroscopic investigation of light hydrides, such as hydrogen sulfide, is challenging due to strong hyperfine interactions and/or anomalous centrifugal-distortion effects. Several hydrides have already been detected in the interstellar medium, and the list includes H2S and some of its isotopologues. Astronomical observation of isotopic species and, in particular, those bearing deuterium is important to gain insights into the evolutionary stage of astronomical objects and to shed light on interstellar chemistry. These observations require a very accurate knowledge of the rotational spectrum, which is so far limited for mono-deuterated hydrogen sulfide, HDS. To fill this gap, high-level quantum-chemical calculations and sub-Doppler measurements have been combined for the investigation of the hyperfine structure of the rotational spectrum in the millimeter- and submillimeter-wave region. In addition to the determination of accurate hyperfine parameters, these new measurements together with the available literature data allowed us to extend the centrifugal analysis using a Watson-type Hamiltonian and a Hamiltonian-independent approach based on the Measured Active Ro-Vibrational Energy Levels (MARVEL) procedure. The present study thus permits to model the rotational spectrum of HDS from the microwave to far-infrared region with great accuracy, thereby accounting for the effect of the electric and magnetic interactions due to the deuterium and hydrogen nuclei.
Scaled β-Ga2O3 thin channel MOSFET with 5.4 MV/cm average breakdown field and near 50 GHz fMAX
Authors: Saha Chinmoy Nath , Vaidya Abhishek , Bhuiyan A. F. M. Anhar Uddin , Meng Lingyu , Sharma Shivam , Zhao Hongping , Singisetti Uttam
Published: May 2023

This Letter reports a high performance β-Ga2O3 thin channel MOSFET with T gate and degenerately doped (n++) source/drain contacts regrown by metal organic chemical vapor deposition. Highly scaled T-gate with a gate length of 160–200 nm was fabricated to achieve enhanced RF performance and passivated with 200 nm silicon nitride. Peak drain current (ID,MAX) of 285 mA/mm and peak transconductance (gm) of 52 mS/mm were measured at 10 V drain bias with 23.5 Ω mm on resistance (RON). Metal/n++ contact resistance of 0.078 Ω mm was extracted from transfer length measurements. RON is possibly dominated by interface resistance between channel and highly doped n++ regrown layer. A gate-to-drain breakdown voltage of 192 V is measured for LGD = 355 nm resulting in average breakdown field (EAVG) of 5.4 MV/cm. This EAVG is the highest reported among all sub-micron gate length lateral FETs. Current gain cut off frequency (fT) of 11 GHz and record power gain cut off frequency (fMAX) of approximately 48 GHz were extracted from small signal measurements. fT is limited by DC-RF dispersion due to interface traps which needs further investigation. The fT·VBR product is 2.112 THz V for 192 V breakdown voltage. Device surpasses the switching figure of merit of Silicon and competitive with mature wide bandgap devices.
Development and performance of a gelatin-based bio-polysaccharide drag reduction coating
Authors: Xie Luo , Jiang Lang , Meng Fan-Zhe , Li Qiang , Wen Jun , Hu Hai-Bao
Published: May 2023

The secreting drag reduction mucus in fish epiderm inspires the manufacturing of five gelatin–polysaccharide drag reduction coatings. First, a mixed solution composed of the gelatin and bio-polysaccharides [guar gum, xanthan gum, locust bean gum, tragacanth gum, or acacia gum] was poured into rectangular grooved polymethyl methacrylate (PMMA) plates, and bionic coatings were obtained after curing. Then, the surface characteristics of the coatings were characterized, and the internal micro-/nanoscale three dimensional (3D) net structures provided releasing access for the polysaccharide molecules. Importantly, a parametric study focusing on the gelatin and polysaccharide proportion affected the drag reduction of the coatings in a turbulent channel flow. Based on a smooth PMMA plate without a coating as a reference, the five developed coatings exhibited considerable drag-reducing effects with the corresponding maximum drag reduction rates that all exceeded 20%. There are three drag reduction mechanisms (polymer drag reduction, slip phenomenon, and wall flexibility) and one drag increase mechanism (surface roughness). Increasing the gelatin proportion affects the release rate of the drag-reducing agents, surface flexibility, and surface slip properties. Meanwhile, increasing the polysaccharide proportion promotes the release of polysaccharides, but increases the surface roughness. Thus, the effects of gelatin and polysaccharide are complicated due to competition between these mechanisms. Future works should focus on clarifying the complex mechanisms to improve the drag reduction efficiency of the gelatin-based bio-polysaccharide coatings. These biomimetic drag-reducing coatings could be further applied to underwater equipment.
Thermal switch based on ferroelasticity VA-N binary compounds
Authors: Zhang Yuwen , Cui Chunfeng , Ouyang Tao , He Chaoyu , Li Jin , Chen Mingxing , Tang Chao
Published: May 2023

Ferroelastic materials possess two or more equally stable orientation variants and can be effectively modulated via external fields, including stress and electronic field. In this paper, taking the VA-N ferroelastic materials as examples, we propose a thermal switch device based on their ferroelastic characteristics. The results show that the VA-N binary compound exhibits excellent ferroelasticity, high reversible elastic strain (5.5%–54.1%), and suitable switching energy barriers (0.012–0.386 eV/atom) in both δ and α phases. Utilizing the advanced on-the-fly machine learning potential, we obtain physically well-defined quadratic dispersion curves in the long-wavelength limit and further evaluate their lattice thermal conductivity of δ and α phase VA-N binary compounds. Due to the difference in phonon group velocities, the lattice thermal conductivity of VA-N binary compounds along the armchair direction is obviously smaller than that along the zigzag direction. Such remarkable anisotropy and easily switchable features based on ferroelasticity endow reversible and real-time regulation of thermal conductivity of VA-N binary compounds. The ferroelastic-based thermal switch hosts high switch ratios range from 2.08 to 5.99 and does not require additional energy to maintain the modulation state. The results presented herein provide a pavement for designing next-generation thermal switches and propose a reliable solution for eliminating the nonphysical pseudo-phenomenon of phonon dispersion curve violation of quadratic dispersion in the long-wavelength limit.
On the development of proteomics: a brief history
Authors: Bradshaw Ralph A.
Published: May 2023

Although one can trace the roots of proteomics well back into the 20th century, it is basically a discipline of the new millennium. At its outset, it was defined primarily by the technology available to analyze complex mixtures (basically 2D-gel electrophoresis, hybridizations/arrays and mass spectrometry) and what mainly set it aside from protein chemistry, that had flourished since the end of the second world war, was this use of unfractionated starting material as opposed to homogenous samples. Early on, two major new insights were quickly revealed: that the protein complement of cells was overwhelmingly involved in multiple protein–protein interactions and that it was nearly universally involved in a myriad of post-translational modifications. The revelations of the complex networks that result from these two phenomena have created a new understanding of cell biology that has affected our appreciation of such processes as transcription and translation, transmembrane signaling, differentiation, homeostasis and cell death. The development of these methods and strategies that principally characterize the field of proteomics depended heavily on the evolution of those that advanced protein chemistry, particularly during the last half of the twentieth century leading up to the elucidation of the human genome and will be briefly summarized in this article.
Schnurri-3 inhibition suppresses bone and joint damage in models of rheumatoid arthritis
Authors: Stavre Zheni , Kim Jung-Min , Yang Yeon-Suk , Nündel Kerstin , Chaugule Sachin , Sato Tadatoshi , Park Kwang Hwan , Gao Guangping , Gravallese Ellen M. , Shim Jae-Hyuck
Published: May 2023

Rheumatoid arthritis (RA) is a chronic inflammatory disease that leads to systemic and articular bone loss by activating bone resorption and suppressing bone formation. Despite current therapeutic agents, inflammation-induced bone loss in RA continues to be a significant clinical problem due to joint deformity and lack of articular and systemic bone repair. Here, we identify the suppressor of bone formation, Schnurri-3 (SHN3), as a potential target to prevent bone loss in RA. SHN3 expression in osteoblast-lineage cells is induced by proinflammatory cytokines. Germline deletion or conditional deletion of
Shn3
in osteoblasts limits articular bone erosion and systemic bone loss in mouse models of RA. Similarly, silencing of SHN3 expression in these RA models using systemic delivery of a bone-targeting recombinant adenoassociated virus protects against inflammation-induced bone loss. In osteoblasts, TNF activates SHN3 via ERK MAPK-mediated phosphorylation and, in turn, phosphorylated SHN3 inhibits WNT/β-catenin signaling and up-regulates RANKL expression. Accordingly, knock-in of a mutation in
Shn3
that fails to bind ERK MAPK promotes bone formation in mice overexpressing human TNF due to augmented WNT/β-catenin signaling. Remarkably, Shn3-deficient osteoblasts are not only resistant to TNF-induced suppression of osteogenesis, but also down-regulate osteoclast development. Collectively, these findings demonstrate SHN3 inhibition as a promising approach to limit bone loss and promote bone repair in RA.
Communication in child language brokering
Authors: Angelelli Claudia V. , Ceccoli Federica
Published: May 2023

Child Language Brokering (CLB) refers to the mediation and translation activities performed by bi/multilingual children and adolescents for their peers, family members, and/or other people belonging to their linguistic community who may not be proficient enough to communicate in the societal language. Since child language brokers engage in interpreted communicative events and implement communicative strategies, one interesting but also controversial area of CLB is the communicative role children play and the expectations of other parties about that role. In this paper we examine frequent communication strategies implemented by a child language broker and study if/how they meet the other parties’ expectations. Specifically, two child language brokering strategies are examined: replacement of a monolingual interlocutor and summarizing of the monolingual interlocutors’ statements. We also discuss child language brokers’ roles and their alignment with adults’ expectations, an innovative focus that merits deeper discussion.
Recruitment of the SNX17-Retriever recycling pathway regulates synaptic function and plasticity
Authors: Rivero-Ríos Pilar , Tsukahara Takao , Uygun Tunahan , Chen Alex , Chavis Garrett D. , Giridharan Sai Srinivas Panapakkam , Iwase Shigeki , Sutton Michael A. , Weisman Lois S.
Published: May 2023

Trafficking of cell-surface proteins from endosomes to the plasma membrane is a key mechanism to regulate synaptic function. In non-neuronal cells, proteins recycle to the plasma membrane either via the SNX27-Retromer-WASH pathway or via the recently discovered SNX17-Retriever-CCC-WASH pathway. While SNX27 is responsible for the recycling of key neuronal receptors, the roles of SNX17 in neurons are less understood. Here, using cultured hippocampal neurons, we demonstrate that the SNX17 pathway regulates synaptic function and plasticity. Disruption of this pathway results in a loss of excitatory synapses and prevents structural plasticity during chemical long-term potentiation (cLTP). cLTP drives SNX17 recruitment to synapses, where its roles are in part mediated by regulating the surface expression of β1-integrin. SNX17 recruitment relies on NMDAR activation, CaMKII signaling, and requires binding to the Retriever and PI(3)P. Together, these findings provide molecular insights into the regulation of SNX17 at synapses and define key roles for SNX17 in synaptic maintenance and in regulating enduring forms of synaptic plasticity.
Waveform uncertainty quantification and interpretation for gravitational-wave astronomy
Authors: Read Jocelyn
Published: May 2023

We demonstrate how to quantify the frequency-domain amplitude and phase accuracy of waveform models,

δ
A

and δφ, in a form that could be marginalized over in gravitational-wave inference using techniques currently applied for quantifying calibration uncertainty. For concreteness, waveform uncertainties affecting neutron-star inspiral measurements are considered, and post-hoc error estimates from a variety of waveform models are made by comparing time-domain and frequency-domain analytic models with multiple-resolution numerical simulations. These waveform uncertainty estimates can be compared to GW170817 calibration envelopes or to Advanced LIGO and Virgo calibration goals. Signal-specific calibration and waveform uncertainties are compared to statistical fluctuations in gravitational-wave observatories, giving frequency-dependent modeling requirements for detectors such as Advanced LIGO Plus, Cosmic Explorer, or Einstein Telescope. Finally, the distribution of waveform error for the GW170817 posterior is computed from tidal models and compared to the constraints on δφ or

δ
A

from GWTC-1 by Edelman et al. In general, δφ and

δ
A

can also be interpreted in terms of unmodeled astrophysical energy transfer within or from the source system.
Fiber optic Michelson interference experimental course towards the cultivation of undergraduates majoring in optical engineering
Authors: Zhang Min , Gao Jiaxing , Liu Zhihai , Zhang Yu , Zhang Yaxun , Yang Xinghua , Zhang Jianzhong , Yang Jun , Yuan Libo
Published: May 2023

With the development of optical engineering technologies, traditional experimental courses that merely demonstrate theoretical phenomena can no longer meet the demands of optical engineers’ education. In this paper, we propose an experimental course ‘Fiber-Michelson white light interference experiment’ towards the cultivation of optical engineering undergraduates and present a fiber optic system supporting the course. The proposed course integrates fiber optics and optical engineering applications with traditional Michelson interference experimental course, and the experimental system used in the course is low in cost, easy to operate, and convenient to assemble. During the class, students work as groups and have to finish three experimental tasks including the measurements of length, curvature, and refractive index. The first-hand experiences in experiments can impress students with the Michelson optic interference theory and is conductive to developing their abilities to apply optics to engineering. Students’ feedbacks are collected by questionnaire, and students recognize the necessity and effectiveness of the course.
TRAC method in dissipative media—a first analysis in frequency domain and homogeneous media
Authors: Graff Marie , Cullen Mina
Published: May 2023

We propose to explore the time-reversed absorbing condition (TRAC) method in the case of dissipative homogeneous media. In previous work, the TRAC method was derived from the time-reversibility of the (undamped) wave equation and proved to be efficient in both the time-domain and the frequency-domain. Namely, two main utilisations of the TRAC method have been probed: (a) redatuming, i.e. moving virtually the measurements by reconstructing the wavefield and (b) tracking down the location of a possible inclusion inside the domain. In this paper, we focus on the redatuming application and investigate the feasibility of the TRAC method in the case of dissipation. In particular, we will see that performing the classical TRAC method, i.e. ignoring the dissipation, may give satisfactory results, even for larger values of dissipation. An analysis is provided in the frequency-domain and one-space dimension and shows satisfactory updated versions of the TRAC method. Moreover, a systematic error study in two-space dimension is illustrated via numerical examples.
Flow recovery from distal pressure in linearized hemodynamics: an optimal control approach
Authors: Imperiale Sébastien , Manganotti Jessica , Moireau Philippe
Published: May 2023

The goal of this work is to derive a reliable stable and accurate inverse problem strategy for reconstructing cardiac output blood flow entering the ascending aorta from pressure measurements at a distal site of the arterial tree, assumed here to be the descending aorta. We assume that a reduced one-dimensional model of the aorta can be linearized around its steady state, resulting in a wave system with absorbing boundary condition at the outlet. Using this model, we attempt to reconstruct the inlet flow from a pressure measurement at the distal outlet. First, we investigate the observability of the problem and prove that the inversion of the input-output operator for the flow and pressure in the space of time-periodic solutions is ill-posed of degree one. We then develop a variational approach where we minimize the discrepancy between measurements and a simulated state and penalize the error with respect to a periodic state. It is shown that the penalty strategy is convergent and provides an efficient solution for the minimization. Numerical results illustrate the robustness of our approach to noise and the potential of our method to reconstruct inlet flow from real pressure recordings during anesthesia.
Impurity effects on the zeroth pseudo-Landau level in twisted bilayer graphene
Authors: Ji Haijiao , Liu Haiwen , Xie X C
Published: May 2023

We theoretically study the impurity effects on the zeroth pseudo-Landau level (PLL) representation of the flat band in a twisted bilayer graphene (TBG) system. Our research investigates the impact of both short-range and long-range charged impurities on the PLL using the self-consistent Born approximation and random phase approximation. Our findings indicate that short-range impurities have a significant effect on the broadening of the flat band due to impurity scattering. In contrast, the impact of long-range charged impurities on the broadening of the flat band is relatively weak, and the primary impact of the Coulomb interaction is the splitting of the PLL degeneracy when a certain purity condition is satisfied. As a result, spontaneous ferromagnetic flat bands with nonzero Chern numbers emerge. Our work sheds light on the effect of impurities on the quantum Hall plateau transition in TBG systems.
Vortex supersolid in the XY model with tunable vortex fugacity
Authors: Maccari I , Defenu N , Castellani C , Enss T
Published: May 2023

In this paper, we investigate the XY model in the presence of an additional potential term that independently tunes the vortex fugacity favouring their nucleation. By increasing the strength of this term and thereby the vortex chemical potential µ, we observe significant changes in the phase diagram with the emergence of a normal vortex-antivortex lattice as well as a superconducting vortex-antivortex crystal (lattice supersolid) phase. We examine the transition lines between these two phases and the conventional non-crystalline one as a function of both the temperature and the chemical potential. Our findings suggest the possibility of a peculiar tricritical point where second-order, first-order, and infinite-order transition lines meet. We discuss the differences between the present phase diagram and previous results for two-dimensional Coulomb gas models. Our study provides important insights into the behaviour of the modified XY model and opens up new possibilities for investigating the underlying physics of unconventional phase transitions.
A novel whale-based algorithm for optimizing the ANN approach: application to temperature compensation in pressure scanner calibration systems
Authors: Wang Huan , Zeng Qinghua , Zhang Zongyu , Zou Yijun
Published: May 2023

To resolve the nonlinear measured values of pressure scanners with temperature change during pressure measurements, resulting in low accuracy, this paper proposes and develops a new calibration system based on neural networks for pressure scanners. Specifically, we first calibrate the pressure scanner production process, then design the sealing device applicable to the working environment of pressure scanners, and finally install the calibration system of the pressure scanner for calibration experiments to obtain accurate measurement results. In addition, at the algorithmic level, this paper forwards a whale optimization algorithm-based backpropagation neural network method instead of the traditional least squares method to complete the temperature compensation. Both the offline compensation results and the compensated online experimental results exhibit the high measurement accuracy of this temperature compensation method. The full-scale (FS) error is 0.07%, the coefficient of determination (R
2) = 99.27%, with similar results for all channels of the pressure sensor in the temperature environment of −40 °C to 60 °C and absolute pressures ranging from 0 to 1.1 MPa. This result presents a significant reduction in the FS error of 0.25%, R
2 = 91.32% based on the conventional algorithm compensation, and also applies to pressure scanners with wide temperature region, wide range, and high accuracy temperature compensation, which is crucial for their future research of low-cost overall calibration and high accuracy algorithms.
First-principles and machine learning modeling on adsorption of atmospheric gases on two-dimensional Ruddlesden–Popper halide perovskite surface
Authors: Zhang Lei , Li Shenyue , Hu Wenguang
Published: May 2023

The interactions between the atmospheric gases and the halide perovskite materials are receiving attention in these years before the extensive industrial deployment of halide perovskite materials. In this manuscript, we combine first-principles calculation and machine learning techniques to evaluate the interactions between the atmospheric gas molecules and a two-dimensional Ruddlesden–Popper halide perovskite Cs2PbBr4 surface based on the adsorption energies and automatically design advanced molecular descriptors for the target output. The impacts of density functionals are considered while an accurate machine learning model (r = 0.954 and R
2 = 0.951) is obtained based on the XGBRF ensemble algorithm. Importantly, the symbolic regression automatically finds an effective hybrid descriptor that exhibits high correlation with the target output that is comparable with the machine learning model; the symbolic regression-derived descriptor is mathematically simple and chemistry-aware, which complements the debatable ‘black-box’ machine learning model. Both feature importance ranking and symbolic regression indicate the importance of the functional-dependent energy levels of the perovskite systems and the amide/hydroxyl functional groups of the molecules. The present study highlights the viability of combining density functional theory and machine learning techniques to model the low-dimensional perovskite structures under the atmospheric conditions.
Enhanced dehydrogenation properties of MgH2 by the synergetic effects of transition metal carbides and graphene
Authors: Zhu Xueqin , Yang Minjian , Luo Minmin , Wang Yonghong , Li Hong , Ding Juntao , Ma Liqiang
Published: May 2023

Transition metal carbides show remarkable catalysis for MgH2, and the addition of carbon materials can attach excellent cycling stability. In this paper, Mg-doped with transition metal carbides (TiC) and graphene (G) composite (denoted as Mg–TiC–G) is designed to assess the influence of TiC and graphene on the hydrogen storage performance of MgH2. The as-prepared Mg–TiC–G samples showed favorable dehydrogenation kinetics compared to the pristine Mg system. After adding TiC and graphene, the dehydrogenation activation energy of MgH2 decreases from 128.4 to 111.2 kJ mol−1. The peak desorption temperature of MgH2 doped with TiC and graphene is 326.5 °C, which is 26.3 °C lower than the pure Mg. The improved dehydrogenation performance of Mg–TiC–G composites is attributed to synergistic effects between catalysis and confinement.
Autonomous x-ray scattering
Authors: Yager Kevin G , Majewski Pawel W , Noack Marcus M , Fukuto Masafumi
Published: May 2023

Autonomous experimentation (AE) is an emerging paradigm that seeks to automate the entire workflow of an experiment, including—crucially—the decision-making step. Beyond mere automation and efficiency, AE aims to liberate scientists to tackle more challenging and complex problems. We describe our recent progress in the application of this concept at synchrotron x-ray scattering beamlines. We automate the measurement instrument, data analysis, and decision-making, and couple them into an autonomous loop. We exploit Gaussian process modeling to compute a surrogate model and associated uncertainty for the experimental problem, and define an objective function exploiting these. We provide example applications of AE to x-ray scattering, including imaging of samples, exploration of physical spaces through combinatorial methods, and coupling to in situ processing platforms These uses demonstrate how autonomous x-ray scattering can enhance efficiency, and discover new materials.
Homogenization for sub-riemannian Lagrangians
Authors: Sánchez Morgado Héctor
Published: May 2023

We consider Lagrangians that are defined only on the horizontal distribution of a sub-riemannian manifold. The associated Hamiltonian is neither strictly convex nor coercive. We prove a result on homogenization of the Hamilton–Jacobi equation following the approach in Contreras et al (2015 Calc. Var. Partial Differ. Equ.
52 237–52). To establish the result, we need to extend weak KAM and Aubry–Mather theories to the sub-riemannian setting. We obtain a Tonelli theorem to dispend of the Lagrangian dynamics tools used in standard weak KAM theory. In the way towards our main result we observe that, the long time convergence of the Lax-Oleinik semigroup, and the vanishing discount convergence of the discounted value function hold.
The first PET glimpse of a proton FLASH beam
Authors: Abouzahr F , Cesar J P , Crespo P , Gajda M , Hu Z , Kaye W , Klein K , Kuo A S , Majewski S , Mawlawi O , Morozov A , Ojha A , Poenisch F , Polf J C , Proga M , Sahoo N , Seco J , Takaoka T , Tavernier S , Titt U , Wang X , Zhu X R , Lang K
Published: May 2023

We demonstrate the first ever recorded positron-emission tomography (PET) imaging and dosimetry of a FLASH proton beam at the Proton Center of the MD Anderson Cancer Center. Two scintillating LYSO crystal arrays, read out by silicon photomultipliers, were configured with a partial field of view of a cylindrical poly-methyl methacrylate (PMMA) phantom irradiated by a FLASH proton beam. The proton beam had a kinetic energy of 75.8 MeV and an intensity of about 3.5 × 1010 protons that were extracted over 101.5 ms-long spills. The radiation environment was characterized by cadmium–zinc–telluride and plastic scintillator counters. Preliminary results indicate that the PET technology used in our tests can efficiently record FLASH beam events. The instrument yielded informative and quantitative imaging and dosimetry of beam-activated isotopes in a PMMA phantom, as supported by Monte Carlo simulations. These studies open a new PET modality that can lead to improved imaging and monitoring of FLASH proton therapy.
Cancer prediction from few amounts of histology samples through self-attention based multi-routines cross-domains network
Authors: Wang Jianqi , Zhang Quan , Liu Guohua
Published: May 2023

Objective. Rapid and efficient analysis of cancer has become a focus of research. Artificial intelligence can use histopathological data to quickly determine the cancer situation, but still faces challenges. For example, the convolutional network is limited by the local receptive field, human histopathological information is precious and difficult to be collected in large quantities, and cross-domain data is hard to be used to learn histopathological features. In order to alleviate the above questions, we design a novel network, Self-attention based multi-routines cross-domains network (SMC-Net). Approach. Feature analysis module and decoupling analysis module designed are the core of the SMC-Net. The feature analysis module base on multi-subspace self-attention mechanism with pathological feature channel embedding. It in charge of learning the interdependence between pathological features to alleviate the problem that the classical convolution model is difficult to learn the impact of joint features on pathological examination results. The decoupling analysis module base on the designed multi-channel and multi-discriminator architecture. Its function is to decouple the features related to the target task in cross-domain samples so that the model has cross-domain learning ability. Main results. To evaluate the performance of the model more objectively, three datasets are used. Compared with other popular methods, our model achieves better performance without performance imbalance. In this work, a novel network is design. It can use domain-independent data to assist in the learning of target tasks, and can achieve acceptable histopathological diagnosis results even in the absence of data. Significance. The proposed method has higher clinical embedding potential and provides a viewpoint for the combination of deep learning and histopathological examination.
Efficient proton-carbon ions acceleration by the plasma-beat-wave mechanism in the presence of the axial magnetic field
Authors: Mehrangiz Mahsa , Khoshbinfar Soheil
Published: May 2023

It is possible to generate the low-divergence ion bunches through the interaction of equally or slightly different counter-propagating laser pulses. In this paper, in the framework of plasma beat wave, we have numerically simulated the simultaneous acceleration of carbon/hydrogen ion beams. Using a two-dimensional particle-in-cell simulation, we have shown that in an HC plasma mixture with an optimal hydrogen ratio of 1:5, the laser reflectivity coefficient reduces up to about 4.6%. This condition may provide the acceleration of low-divergence H+ and C4+ ions beam. The cut-off energy for protons and C4+ ions are about 27 MeV and 410 MeV, respectively at n
H = 0.2 n
C. The values increase by about 15.6% for protons and 21% for C4+ at n
H = 0.7 n
C. In the presence of an axial magnetic field, the energy absorption arrives at its maximum at the values of Ωs/ω
p = 0.1, where Ωs and ω
p are the gyro-frequency and plasma frequency, respectively. Here, the average kinetic energy of the accelerated ions raises by 17.9% and 7.3% for carbon and proton ions, respectively. Compared to the magnetic field-free case, divergence angles were suppressed at approximately 24.2% and 20.3% for the carbon ions and hydrogen ions, respectively.