bluuebunny/crossref_metadata_2025 huggingface dataset:
The Influence of Knee Osteoarthritis on Spinopelvic Alignment and Global Sagittal Balance
Authors: Katsumi Ryota , Mannen Erin M. , Bajaj Gitanjali , Smith Jacob R. , Mears Simon C. , Stambough Jeffrey B. , Barnes C. Lowry
Published: May 2022

Osteoarthritis (OA) of the knee is thought to lead to a loss of lumbar lordosis (LL) as a compensation for knee flexion contracture. Changes in sagittal alignment are not limited to the lumbar spine and involve a complex interplay of alignment of the hip, pelvis, and spine. While spine–hip interactions have been previously explored, the influence of knee OA sagittal alignment parameters on spinopelvic alignment and global sagittal balance remains unexplored. Standing radiological examination using EOS biplanar radiography was examined in 108 patients with knee OA. Whole-body sagittal alignment parameters (thoracic kyphosis, LL, pelvic incidence, pelvic tilt [PT], femoropelvic angle [FPA], femoral tilt angle [FTA], tibial tilt angle, and knee flexion angle [KFA]) and global balance parameters (sagittal vertical axis [SVA] and odontoid hip axis [OD-HA] angle) were measured three dimensionally (3D). The correlation coefficients among all parameters were assessed. A multiple stepwise linear regression model was built to investigate the direct association between SVA or OD-HA angle (dependent variables) and sagittal alignment parameters and demographic data (independent variables). Significant correlations between KFA, FPA, FTA, SVA, and OD-HA angle were found. FTA was correlated with LL and FPA. The FTA was the most influential predictor of both global sagittal balance parameters (p < 0.001). Knee OA leads to changes in global sagittal balance with effects at the hip, knee, pelvis, and spine. FTA (forward flexion of the femur vs. the vertical plane) is the largest driver of global sagittal plane balance in patients with knee OA.
Finding alternative uses for solar thermal energy
Authors: Thompson Avery
Published: May 2022

Particle-based solar thermal energy can be used as a cost-effective source of heat for many of Australia’s industries.
Simulating a pulsed-power-driven plasma with ideal MHD
Authors: Beresnyak A. , Velikovich A. L. , Giuliani J. L. , Jackson S. L. , Engelbrecht J. T. , Richardson A. S. , Dasgupta A.
Published: May 2022

We describe a simple practical numerical method for simulating plasma driven within a vacuum chamber by a pulsed power generator. Typically, in this type of simulation, the vacuum region adjacent to the plasma is approximated as a highly resistive, light fluid; this involves computationally expensive solvers describing the diffusion of the magnetic field through this fluid. Instead, we provide a recipe for coupling pulsed power generators to the magnetohydrodynamics (MHD) domain by approximating the perfectly insulating vacuum as a light, perfectly conducting, inviscid MHD fluid and discuss the applicability of this counter-intuitive technique. This much more affordable ideal MHD representation is particularly useful in situations where a plasma exhibits interesting three-dimensional phenomena, either due to the design of the experiment or due to developing instabilities. We verified that this coupling recipe works by modeling an exactly solvable flux compression generator as well as a self-similar Noh-like solution and demonstrated convergence to the theoretical solution. We also showed examples of simulating complex three-dimensional pulsed power devices with this technique. We release our code implementation to the public (see https://github.com/beresnyak/verif_coupling).
Method to extracting the penetration field in superconductors from DC magnetization data
Authors: Talantsev Evgueni F.
Published: May 2022

The lower critical field, Bc1, is one of the fundamental quantities of a superconductor that directly manifests the Cooper pair bulk density in the material. Although this field can be measured using several techniques, the most conventional method is to calculate this field from the experimentally measured DC penetration field, Bp, which is defined as the starting point of the deviation of the DC magnetization curve, M(Bappl), from a linear dependence. Surprisingly, we found no mathematical routine that describes how this starting point of deviation can be found. Here, we propose the extraction of Bp from the fit of the M(Bappl) dataset to the power law, where the threshold criterion Mc can be established by a convention. The advantage of this approach is that the procedure extracts one additional characteristic parameter: the power-law exponent. We demonstrated the applicability of this approach to polycrystalline ThIr3, WB4.2, BaTi2Bi2O, and Th4H15; thin films of Pb and MgB2; and Nb single crystal. In most reports, Bc1(T) analysis is limited by the extraction of the London penetration depth. We advanced the analysis to extract primary thermodynamic superconducting parameters [i.e., the ground state superconducting energy gap, Δ(0); the relative jump in electronic specific heat at transition temperature, ΔCγTc; and the gap-to-transition temperature ratio, 2Δ0kBTc] from Bc1(T) data. This extraction was performed for Nb, ThIr3, TaRh2B2, and NbRh2B2.
Organic axial stretching DFB fiber laser hydrophones: Theoretical and experimental study of eccentricity
Authors: Song Wenzhang , Huang Junbin , Gu Hongcan , Tang Bo , Zhou Xuan , Pang Yandong , Chen Sitong , Zhu Miao
Published: May 2022

For the structure of the organic material axial stretching distributed feedback (DFB) fiber laser hydrophones, both ends are sensitized by the organic material perfusion molding. During encapsulation, when the DFB laser fiber is not precisely fixed to the central axis of the sleeve, the fiber will produce eccentricity after the organic matters are solidified. Therefore, the theoretical model of eccentricity was established in this paper, and the influence of eccentricities on frequency response characteristics of hydrophones was analyzed with the finite element method, and the experimental verification was carried out. Simulation and experimental results indicated that this eccentricity will reduce the sensitivity of DFB fiber laser hydrophones about 2 dB and increase the frequency response fluctuation about 3 dB, which is the key factor to be controlled in the packaging process.
Electric-field-driven resistive transition in multiferroic SrCo2Fe16O27/Sr3Co2Fe24O41 composite
Authors: Mishra Shubhankar , Sahoo Aditi , Mondal Suchanda , Mandal P. , Kumar Ghosh Chandan , Bhattacharya Dipten
Published: May 2022

We report on the observation of electric-field-driven resistive transition [abrupt rise in resistivity (ρ)] at a characteristic threshold field Eth(T) in an off-stoichiometric composite of W- and Z-type hexaferrite (∼80%)SrCo2Fe16O27/(∼20%)Sr3Co2Fe24O41. The dielectric constant ε and the relaxation time constant τ also exhibit anomalous jump at Eth(T). The Eth(T), the extent of jump in resistivity (Δρ), and the hysteresis associated with the jump [ΔEth(T)] are found to decrease systematically with the increase in temperature (T) across a range of 10–200 K. They also depend on the extent of nonstoichiometry. In addition, several temperature-driven phase transitions have been noticed both in the low and high resistive states. The entire set of observations has been discussed within the framework of structural evolution of the point defect (cation vacancies or oxygen excess) network and its influence on electronic conduction. The magnetocapacitive effect, measured under ∼20 kOe field, turns out to be substantial (∼4%–12%) and exhibits clear anomaly at Eth. This comprehensive map of esoteric ρ−E−T and ε−E−T patterns provides insights on defect-driven effects in a multiferroic composite. These effects could be useful for tuning both the resistive transition and the multiferroicity.
Science, serendipity, coincidence, and the Oregonator at the University of Oregon, 1969–1974
Authors: Field Richard J. , Mazo Robert M. , Manz Niklas
Published: May 2022

This historical review of the development of the Oregonator model of the Belousov–Zhabotinsky reaction is based on a lecture Dick Field presented during IrvFest2015—Celebrating a founding father of chaos!, a meeting in commemoration of Irving R. Epstein’s 70th birthday. For Dick’s 80th birthday festschrift, we focus here on the five papers in the series named “Oscillations in chemical systems,” published in 1972 [Noyes et al., J. Am. Chem. Soc. 94, 1394–1395 (1972); Field et al., J. Am. Chem. Soc. 94, 8649–8664 (1972); Field and Noyes, Nature 237, 390–392 (1972)] and 1974 [Field and Noyes, J. Chem. Phys. 60, 1877–1884 (1974); Field and Noyes, J. Am. Chem. Soc. 96, 2001–2006 (1974)].
MENUS—Materials engineering by neutron scattering
Authors: An Ke , Stoica Alexandru D. , Huegle Thomas , Lin Jiao Y. Y. , Graves Van
Published: May 2022

Materials engineering by neutron scattering (MENUS) at the second target station will be a transformational high-flux, versatile, multiscale materials engineering diffraction beamline with unprecedented new capabilities for the study of complex materials and structures. It will support both fundamental and applied materials research in a broad range of fields. MENUS will combine unprecedented long-wavelength neutron flux and unique detector coverage to enable real-time studies of complex structural and functional materials under external stimuli. The incorporated small angle neutron scattering and transmission/imaging capabilities will extend its sensitivity to larger length scales and higher spatial resolution. Multimodal MENUS will provide crystallographic and microstructure data to the materials science and engineering community to understand lattice strain/phase transition/microstructure/texture evolution in three orthogonal directions in complex material systems under combined extreme applied conditions. The capabilities of MENUS will open new scientific opportunities and meet the research needs for science challenges to enable studies of a range of phenomena and answer the key questions in material design/exploration, advanced material processing, transformative manufacturing, and material operations of national impacts in our daily life.
HfO2-based memristor-CMOS hybrid implementation of artificial neuron model
Authors: Zhang Yinxing , Fang Ziliang , Yan Xiaobing
Published: May 2022

Memristors with threshold switching behavior are increasingly used in the study of neuromorphic computing, which are frequently used to simulate synaptic functions due to their high integration and simple structure. However, building a neuron circuit to simulate the characteristics of biological neurons is still a challenge. In this work, we demonstrate a leaky integrate-and-fire model of neurons, which is presented by a memristor-CMOS hybrid circuit based on a threshold device of a TiN/HfO2/InGaZnO4/Si structure. Moreover, we achieve multiple neural functions based on the neuron model, including leaky integration, threshold-driven fire, and strength-modulated spike frequency characteristics. This work shows that HfO2-based threshold devices can realize the basic functions of spiking neurons and have great potential in artificial neural networks.
Multilayer transducer for highly efficient initiation of time-resolved Brillouin scattering
Authors: Bruno François , Saint-Martin Loïc , Thuau Damien , Audoin Bertrand
Published: May 2022

Structures made of a metallic film deposited on a substrate are conventionally used as opto-acoustic transducers for picosecond ultrasonic experiments where detection in the time domain of the Brillouin scattering in a transparent sample is sought. In this paper, we substitute the metallic film for a periodic stack of nanometric layers made of gold and lithium fluoride to increase the amplitude, at the Brillouin frequency shift, of the strain generated by the photo-thermal effect. A model is used to analyze the generated strain amplification with the volume fraction and with the total thickness of this structure and to evaluate the gain in terms of sample dynamic reflectivity changes. Amplification by a factor of 20 is measured when using the composite structure with respect to signals detected with a transducer made of a single gold layer.
High-quality (001) β-Ga2O3 homoepitaxial growth by metalorganic chemical vapor deposition enabled by in situ indium surfactant
Authors: Tang Wenbo , Ma Yongjian , Zhang Xiaodong , Zhou Xin , Zhang Li , Zhang Xuan , Chen Tiwei , Wei Xing , Lin Wenkui , Mudiyanselage Dinusha Herath , Fu Houqiang , Zhang Baoshun
Published: May 2022

(001) β-Ga2O3 homoepitaxy on commercially available large-size (001) β-Ga2O3 substrates remains a significant challenge for the wide bandgap semiconductor community. In this Letter, high-quality homoepitaxial (001) β-Ga2O3 films were grown via metalorganic chemical vapor deposition (MOCVD) with the assistance of an in situ indium surfactant, where the growth modes and mechanisms were also elucidated. During the growth of β-Ga2O3, an etching process occurred by the desorption of the suboxide Ga2O, resulting in rough surface morphology with streaky grooves oriented along the [010] direction. It is postulated that the parallel grooves were associated with the surface desorption and anisotropic diffusion characteristics of β-Ga2O3. To suppress the desorption, indium surfactant was introduced into the growth environment. A 2D-like growth feature was prompted subsequently by the coadsorption of In and Ga atoms, accompanied by relatively smooth surface morphology. The crystal quality had no degradation despite the incorporation of indium in the epitaxial film. The O II peak of the β-Ga2O3 film shifted ∼0.5 eV toward higher binding energy due to an increasing number of oxygen vacancies originating from the indium incorporation. This work provides a systemic investigation on the growth of high-quality (001) β-Ga2O3 homoepitaxial films by MOCVD, which is critical for the development of β-Ga2O3 electronic devices for future power switching and RF applications.
Angle-dependent switching in a magnetic tunnel junction containing a synthetic antiferromagnet
Authors: Chen Hao , Parks Brad , Zhang Qiang , Fang Bin , Zhang Xixiang , Majetich Sara A.
Published: May 2022

The angle dependence of field-induced switching was investigated in magnetic tunnel junctions with in-plane magnetization and a pinned synthetic antiferromagnet reference layer. The 60 × 90 nm2 elliptical nanopillars had sharp single switches when the field was applied along the major axis of the ellipse, but even with small (20°) deviations, reversal occurred through an intermediate state. The results are interpreted with a model that includes the external applied field and the effective fields due to shape anisotropy and the fringe field of the synthetic antiferromagnet and used to extract the magnetization direction at various points in the magnetoresistance loop. The implications for faster spintronic probabilistic computing devices are discussed.
Voltage-controlled reversible modulation of colloidal quantum dot thin film photoluminescence
Authors: Xie Sihan , Zhu Han , Li Melissa , Bulović Vladimir
Published: May 2022

Active modulation of quantum dot thin film photoluminescence (PL) has been far-reaching potential applications in biomedical and optoelectronic systems, but challenges remain in achieving large PL modulation depth and fast temporal response. Here, we report an efficient voltage-controlled optical down-converter by optically exciting a colloidal quantum dot thin film within a quantum dot light-emitting diode under reverse bias. Utilizing field-induced luminescence quenching, we show that a large electric field can strongly modify carrier dynamics in this nanostructured device, resulting in stable and reversible photoluminescence quenching. The device exhibits photoluminescence reduction of up to 99.5%, corresponding to a contrast ratio of 200:1 under the applied electric field of 3 MV cm−1 with a 300 ns response time. Using excitation wavelength dependent and transient PL spectroscopy, we further show that the high degree of quenching is achieved by a synergistic interplay of quantum-confined Stark effect and field-induced exciton dissociation.
Atoms and interatomic bonding synergism inherent in molecular electronic wave functions
Authors: Ruedenberg Klaus
Published: May 2022

The chemical model of matter consists of atoms held together by bonds. The success of this model implies that the physical interactions of the electrons and nuclei in molecules combine into compound interactions that create the bonding. In the quantum mechanical description, the modified atoms in molecules and the bonding synergism are contained in the molecular electronic wave function. So far, only part of this information has been recovered from the wave function. Notably, the atoms have remained unidentified in the wave function. One reason is that conventional energy decomposition analyses formulate separate model wave functions, independent of the actual wave function, to represent “prepared atoms” and preconceived interactions and, then, intuitively catenate the parts. In the present work, the embedded modified atoms and the inherent physical synergisms between them are determined by a unified derivation entirely from the actual molecular valence space wave function. By means of a series of intrinsic orbital and configurational transformations of the wave function, the energy of formation of a molecule is additively resolved in terms of intra-atomic energy changes, interference energies, and quasi-classical, non-classical, and charge-transfer Coulombic interactions. The analysis furnishes an algorithm for the quantitative resolution of the energy of formation, which enables analyses elucidating reaction energies.
Osmotic second virial coefficients for hydrophobic interactions as a function of solute size
Authors: Naito Hidefumi , Okamoto Ryuichi , Sumi Tomonari , Koga Kenichiro
Published: May 2022

To gain quantitative insight into how the overall strength of the hydrophobic interaction varies with the molecular size, we calculate osmotic second virial coefficients B for hydrophobic spherical molecules of different diameters σ in water based on molecular simulation with corrections to the finite-size and finite-concentration effects. It is shown that B (<0) changes by two orders of magnitude greater as σ increases twofold and its solute-size dependence is best fit by a power law B ∝ σα with the exponent α ≃ 6, which contrasts with the cubic power law that the second virial coefficients of gases obey. It is also found that values of B for the solutes in a nonpolar solvent are positive but they obey the same power law as in water. A thermodynamic identity for B derived earlier [K. Koga, V. Holten, and B. Widom, J. Phys. Chem. B 119, 13391 (2015)] indicates that if B is asymptotically proportional to a power of σ, the exponent α must be equal to or greater than 6.
Interstitial proton transport through defective MXenes
Authors: Rayabharam Archith , Aluru N. R.
Published: May 2022

Proton transport across nanometer-thick membranes in an aqueous medium is important for applications in energy and molecular sieving. Recently, Hu et al. [Nature 516(7530), 227–230 (2014)] experimentally demonstrated proton tunneling through 2D materials like graphene and hexagonal boron nitride, opening up a wide range of applications in hydrogen-based technologies such as fuel cells. Here, we demonstrate proton transport in an aqueous medium across a 2D cubic Ti2C membrane, a representative defective MXene, from ab initio molecular dynamics simulations. We observe bidirectional translocation of protons, which occurs through the interstitial vacancies in the surface. We show from our simulations that water dissociates on the membrane and the dissociated proton moves into the interstitial sites in the membrane. The proton hops from interstitial-to-interstitial and transports across the membrane. We also show that this interstitial proton transport is associated with an induced electric field that is modulated with bidirectional transport of protons across the membrane.
Shorebird Flying Adventure
Authors: Kerin Jackie , Formby Milly
Published: May 2022

Join Milly on her microlight adventure and discover how amazing and awesome migratory shorebirds are!

In A Shorebird Flying Adventure you’ll take a trip to the Arctic tundra and back. On the way you’ll meet the birds who travel phenomenal distances every year and explore their precious wetland habitats and breeding grounds. Learn fascinating facts about their diet and find out Milly’s top tips to tell one species from another. Grab your binoculars, hop on board and let’s go bird watching!

Reading level varies from child to child, but we recommend this book for ages 6 to 9.
Solubility of carbon dioxide in some imidazolium and pyridinium-based ionic liquids and correlation with NRTL model
Authors: Noorani Narmin , Mehrdad Abbas
Published: May 2022

In this study, the solubility of carbon dioxide gas in a series of 1-alkyl-4-methyl pyridinium and 1-alkyl-3-methylimidazolium-based ionic liquids with various anions, viz. thiocyanate ([SCN]−), chloride ([Cl]−) and bromide ([Br]−) was investigated using a quartz crystal microbalance at 298.15 K and pressures up to 0.4 MPa. CO2 solubility in the ionic liquids correlates well with the non-random two-liquid (NRTL) model. The results indicate that the cation alkyl chain length and the type of anion have the main effects on the solubility of carbon dioxide in ionic liquids. CO2 solubility in both 1-alkyl-4-methyl pyridinium and 1-alkyl-3-methylimidazolium-based ionic liquids increased with increasing alkyl chain length of the cation. Also, CO2 solubility was strongly dependent on the selection of the anion. CO2 solubility in both 1-alkyl-4-methyl pyridinium and 1-alkyl-3-methylimidazolium-based ionic liquids increased as follows: [SCN]− > [Cl]− > [Br]−.
Trade and foreign fishing mediate global marine nutrient supply
Authors: Nash Kirsty L. , MacNeil M. Aaron , Blanchard Julia L. , Cohen Philippa J. , Farmery Anna K. , Graham N. A. J. , Thorne-Lyman Andrew L. , Watson Reg A. , Hicks Christina C.
Published: May 2022

Significance

The world produces enough food to nourish the global population, but inequitable distribution of food means many people remain at risk for undernutrition. Attainment of Sustainable Development Goal 2 relies on greater attention to distribution processes that match food qualities with dietary deficiencies. We explore this in the context of fisheries. Foreign fishing and international trade divert nutrients caught in marine fisheries from nutrient-insecure toward nutrient-secure nations. Where nutrient-insecure countries do benefit from foreign fishing and trade, there tends to be high vulnerability to future changes in nutrient flows arising from changes to foreign fishing and trade. This research highlights the need for greater transparency around distribution of fish and for nutrition security to be considered more centrally in development of trade agreements.
Twisting for soft intelligent autonomous robot in unstructured environments
Authors: Zhao Yao , Chi Yinding , Hong Yaoye , Li Yanbin , Yang Shu , Yin Jie
Published: May 2022

Soft robots that can harvest energy from environmental resources for autonomous locomotion is highly desired; however, few are capable of adaptive navigation without human interventions. Here, we report twisting soft robots with embodied physical intelligence for adaptive, intelligent autonomous locomotion in various unstructured environments, without on-board or external controls and human interventions. The soft robots are constructed of twisted thermal-responsive liquid crystal elastomer ribbons with a straight centerline. They can harvest thermal energy from environments to roll on outdoor hard surfaces and challenging granular substrates without slip, including ascending loose sandy slopes, crossing sand ripples, escaping from burying sand, and crossing rocks with additional camouflaging features. The twisting body provides anchoring functionality by burrowing into loose sand. When encountering obstacles, they can either self-turn or self-snap for obstacle negotiation and avoidance. Theoretical models and finite element simulation reveal that such physical intelligence is achieved by spontaneously snapping-through its soft body upon active and adaptive soft body-obstacle interactions. Utilizing this strategy, they can intelligently escape from confined spaces and maze-like obstacle courses without any human intervention. This work presents a de novo design of embodied physical intelligence by harnessing the twisting geometry and snap-through instability for adaptive soft robot-environment interactions.
Association between self‐reported sleep characteristics and cardiovascular risk factors: Weight status and physical activity matter
Authors: Valenzuela Pedro L. , Santos‐Lozano Alejandro , Morales Javier S. , Castillo‐García Adrián , Lucia Alejandro
Published: May 2022

We analysed the association between self‐reported sleep characteristics and the prevalence of major cardiovascular disease (CVD) risk factors attending to the potential effect of physical activity (PA) and weight status. A large cohort of Spanish workers (n = 527,662; 32% female, 44 ± 9yrs) participated in this cross‐sectional study. We assessed participants’ self‐reported indicators of sleep quantity (short [<6 h/d], normal [6–9 h/d] or long [>9 h/d]) and quality (unrestful or restful, and difficulties or not falling asleep) as well as the presence of major CVD risk factors (diabetes, hypertension and hypercholesterolemia); and categorised participants based on PA (“inactive”, “insufficiently active” or “regularly active”) and weight status (normal weight, overweight or obesity). Impairments in any sleep quantity or quality indicator, respectively, were significantly (p < 0.05) associated with the prevalence of at least one CVD risk factor. Yet, being physically active and having normal weight markedly attenuated these associations. Thus, individuals with poor sleep quantity or quality but who were physically active and had normal weight showed no different risk of hypertension or diabetes than those with normal sleep characteristics, albeit the former still presented a higher risk of hypercholesterolemia if they reported short sleep (+5% vs. normal duration, p = 0.047), unrestful sleep (+9% vs. restful, p < 0.001) or having difficulties to fall asleep (+48% vs. no difficulties, p < 0.001). The present findings support the need for maintaining optimal PA levels and weight status in order to minimise the CVD risk associated with poor sleep quantity or quality.

Highlights

Both sleep quantity and quality are associated with the prevalence of hypertension, diabetes, and hypercholesterolemia.

Being physically active and having normal weight markedly reduces the cardiovascular risk associated with poor sleep quantity/quality.

Having poor sleep quantity/quality while being also inactive and overweight/obese predisposes to a higher cardiovascular risk.
Reconstitution and mechanistic dissection of the human microtubule branching machinery
Authors: Zhang Yaqian , Hong Xing , Hua Shasha , Jiang Kai
Published: May 2022

Branching microtubule (MT) nucleation is mediated by the augmin complex and γ-tubulin ring complex (γ-TuRC). However, how these two complexes work together to promote this process remains elusive. Here, using purified components from native and recombinant sources, we demonstrate that human augmin and γ-TuRC are sufficient to reconstitute the minimal MT branching machinery, in which NEDD1 bridges between augmin holo complex and GCP3/MZT1 subcomplex of γ-TuRC. The single-molecule experiment suggests that oligomerization of augmin may activate the branching machinery. We provide direct biochemical evidence that CDK1- and PLK1-dependent phosphorylation are crucial for NEDD1 binding to augmin, for their synergistic MT-binding activities, and hence for branching MT nucleation. In addition, we unveil that NEDD1 possesses an unanticipated intrinsic affinity for MTs via its WD40 domain, which also plays a pivotal role in the branching process. In summary, our study provides a comprehensive understanding of the underlying mechanisms of branching MT nucleation in human cells.
Tunable electronic and magnetic properties of Cr2Ge2Te6 monolayer by organic molecular adsorption
Authors: Zhang Jieqi , Zhang Chao , Ren Kai , Lin Xiuling , Cui Zhen
Published: May 2022

Recently, two-dimensional materials are widely concerned because of their novel physical properties. Cr2Ge2Te6(CGT) has been studied extensively due to its intrinsic ferromagnetism and ferromagnetic order. In this investigation, the electronic and magnetic performances of organic molecules (TCNE, TCNQ and TTF) adsorbed on CGT monolayer were studied based on the first-principles calculations systematically. The results demonstrate that the CGT presents pronounced tunable electronic and magnetic properties by the adsorption of these macromolecules. Furthermore, the Curie temperature of CGT monolayer can be enhanced significantly by the TTF adsorption. This work can provide a magnetic regulation method for CGT and explore the promising applications of the CGT for spin devices.
A complementary resistive switching neuron
Authors: Wang Xinxin , Li Huanglong
Published: May 2022

The complementary resistive switching (CRS) memristor has originally been proposed for use as the storage element or artificial synapse in large-scale crossbar array with the capability of solving the sneak path problem, but its usage has mainly been hampered by the inherent destructiveness of the read operation (switching ‘1’ state to ‘ON’ or ‘0’ state). Taking a different perspective on this ‘undesired’ property, we here report on the inherent behavioral similarity between the CRS memristor and a leaky integrate-and-fire (LIF) neuron which is another basic neural computing element, in addition to synapse. In particular, the mechanism behind the undesired read destructiveness for storage element and artificial synapse can be exploited to naturally realize the LIF and the ensuing spontaneous repolarization processes, followed by a refractory period. By means of this biological similarity, we demonstrate a Pt/Ta2O5−x
/TaO
y
/Ta CRS memristor that can exhibit these neuronal behaviors and perform various fundamental neuronal operations, including additive/subtractive operations and coincidence detection. These results suggest that the CRS neuron, with its bio-interpretability, is a useful addition to the family of memristive neurons.
High-performance p-hexafluoroisopropanol phenyl functionalized multi-walled carbon nanotube film on surface acoustic wave device for organophosphorus vapor detection
Authors: Wu Qiang , Li Xue , Wang Xuming , Yuan Yubin , Bu Xiangrui , Wu Haiyang , Li Xin , Han Chuanyu , Wang XiaoLi , Liu Weihua
Published: May 2022

A delay line-type surface acoustic wave (SAW) gas sensor based on p-hexafluoroisopropanol phenyl (HFIPPH) functionalized multi-walled carbon nanotube (MWCNT) film is developed to detect organophosphorus dimethyl methylphosphonate (DMMP) vapor (a simulant of chemical nerve agent sarin). Inspired by the transfer process of Cu-based graphene, a uniform and size-controllable HFIPPH-MWCNT film is successfully prepared on the SAW device via a wet-etching transfer method. For the first time, we use the method of measuring the change of the sensor’s insertion loss to achieve the detection of ultra-low concentration DMMP vapor. The designed sensor exhibits a fast response/recovery time about 3 s/50 s, and a low detection limit of 0.1 ppm. Additionally, the stability and selectivity of the sensor and the influence of humidity on its response are evaluated through experiments. The acoustoelectric effect is proved to be the sensing mechanism of the sensor insertion loss response.
0D/2D mixed-dimensional perovskite constructed by thiol- and disulfide-containing ligands
Authors: Yao Guoying , Zhao Liang , Zeng Tao , Yang Zhenyu
Published: May 2022

Reduced-dimensional (RD) perovskites have shown attractive chemical and physical properties for optoelectronic applications. Incorporating large organic ligands enables infinite tunability in the components and structures. Theoretically, it is feasible to apply multiple types of organic ligands in a single RD crystal to achieve multiple-dimensional perovskites. However, the coexistence of different organic ligands commonly introduces competing crystal growths that inhibit the formation of a more complex crystal structure. Herein, we report a case of mixed-dimensional (MD) perovskite single crystal containing two types of sulfide-containing ligands. We show that the application of ketones can partially oxidize organothiol ligands in the precursor solution. The resultant disulfide-based ligands can be co-incorporated with the thiol-based ligand in a single MD perovskite crystal. X-ray diffraction confirmed that the structure contains both layered and isolated inorganic components constructed by face-sharing lead halide octahedra. Unlike conventional RD structures, the MD perovskite shows an enlarged bandgap with valence band maximum and conduction band minimum being spatially separated, and isotropic optical features, as revealed by x-ray diffraction, spectroscopies, and density functional theory computation.
Uniqueness of the 2D Euler equation on a corner domain with non-constant vorticity around the corner
Authors: Agrawal Siddhant , Nahmod Andrea R
Published: May 2022

We consider the 2D incompressible Euler equation on a corner domain Ω with angle νπ with

1

2

<
ν
<
1

. We prove that if the initial vorticity ω
0 ∈ L
1(Ω) ∩ L
∞(Ω) and if ω
0 is non-negative and supported on one side of the angle bisector of the domain, then the weak solutions are unique. This is the first result which proves uniqueness when the velocity is far from Lipschitz and the initial vorticity is non-constant around the boundary.
High-power cold diodes for the protection of a 1.5 T superconducting MRI magnet system
Authors: Soni Vijay , Gupta Arvind , Kar Soumen
Published: May 2022

Cold diodes play a crucial role in various operational aspects of the superconducting magnet of magnetic resonance imaging (MRI) scanners. The forward and reverse characteristics and failure modes are studied for two types of high-power rectifier diode to find their suitability for application at 4.2 K in a whole-body 1.5 T superconducting MRI magnet system. The diodes are characterized at various temperatures (300 K, 77 K and 4.2 K) in the current range up to 600 A. The turn-on voltage of the diodes at 4.2 K is found to be increased by 7–12 times that of room temperature. The diodes show negative differential resistance (NDR) beyond 1 A of forward current at 4.2 K. The forward voltage stabilizes in the range of 1.22–1.24 V after attaining the turn-on voltage in the range of 5–8 V. The significance of NDR is analysed for the MRI magnet. The long-term stability of the forward voltage is studied at 77 K with 550 A of forward current. Two modes of diode failure are also studied to foresee any failure during the operation of the magnet.
Polymer electrolytes based on magnesium triflate for quasi-solid-state magnesium-sulfur batteries
Authors: Gamal R , Elkalashy Sh I , Sheha E , El Kholy M M
Published: May 2022

Herein, magnesium-ion conducting polymer electrolytes (PE) based on polyvinylidene fluoride (PVDF), tetraethylene glycol dimethyl ether (TEGDME), succinonitrile (SN), and different concentrations of magnesium triflate salt ((CF3SO3)2Mg) were fabricated. The structural, optical, electrical, and electrochemical properties were investigated. The conductivity increases to about 10−5 S.cm−1 with increasing the concentration of (CF3SO3)2Mg up to 33 wt%, at room temperature. The ionic transference number for the matrix containing 33 wt% of (CF3SO3)2Mg increases from (

t

m

g

+
2

 = 0.4) to (

t

M

g

+
2

=
0.8

) with increasing the temperature comparatively from room temperature to 55 °C. Also, the cell with 33 wt% of (CF3SO3)2Mg shows low overpotential and steady Mg stripping/plating during the initial cycles at 55 °C. Polymer and dual electrolytes, as well as bare and modified Mg surface electrodes, are used to create Mg/S cells. The cell with a modified Mg surface electrode and dual electrolyte exhibit lower interfacial impedance, higher energy density, and charge-discharge capacity than the cell with a bare Mg electrode and polymer electrolyte.
Ab-initio study for the elastic stability, mechanical, electronic and optical properties of RuCrX (X = Si, Ge, Sn) half Heusler alloys
Authors: Bakar Abu , Afaq A , Shoaib Muhammad , Dahshan A , Asif Muhammad
Published: May 2022

This paper contains the comparative study of elastic, mechanical, electronic and optical response of RuCrX (X=Si, Ge, Sn). Three independent second order elastic constants are computed and elasto-mechanical stability is checked. Mechanical parameters depicts the flexible and ductile nature. These materials are hard and stiffer, difficult to compress and have an excellent bond stretching minimization phenomenon. The higher melting temperatures make them candidate for the high temperature environment like aerospace and construction industries. The band gap and density of states study reveal the non-magnetic metallic nature of all these alloys. In addition, the Fermi surfaces are also calculated. The imaginary part of dielectric response function confirms the utility in opto-electronic devices and sensors.
Dynamical instability of collapsed dark matter halos
Authors: Feng Wei-Xiang , Yu Hai-Bo , Zhong Yi-Ming
Published: May 2022

A self-interacting dark matter halo can experience gravothermal collapse, resulting in a central core with an ultrahigh density. It can further contract and collapse into a black hole, a mechanism proposed to explain the origin of supermassive black holes. We study dynamical instability of the core in general relativity. We use a truncated Maxwell-Boltzmann distribution to model the dark matter distribution and solve the Tolman-Oppenheimer-Volkoff equation. For given model parameters, we obtain a series of equilibrium configurations and examine their dynamical instability based on considerations of total energy, binding energy, fractional binding energy, and adiabatic index. Our numerical results indicate that the core can collapse into a black hole when the fractional binding energy reaches 0.035 with a central gravitational redshift of 0.5. We further show for the instability to occur in the classical regime, the boundary temperature of the core should be at least 10% of the mass of dark matter particles; for a 109 M⊙ seed black hole, the particle mass needs to be larger than a few keV. These results can be used to constrain different collapse models, in particular, those with dissipative dark matter interactions. https://github.com/michaelwxfeng/truncated-Maxwell-Boltzmann.
A noise statistical distribution analysis-based two-step filtering mechanism for optical coherence tomography image despeckling
Authors: Yu Xiaojun , Ge Chenkun , Li Mingshuai , Chen Jinna , Ping Shum Perry
Published: May 2022

Optical coherence tomography (OCT) inevitably suffers from speckle noises that originate from the coherent multiple-scattered photons. Such speckle noises, following different distribution patterns, can hide tissue microstructures and degrade the disease diagnosis accuracy. So far, various schemes have been proposed for despeckling in OCT images, yet few have evaluated the impacts of different noise patterns on despeckling effects. In this study, we evaluate the influences of statistical noise distributions on OCT despeckling and propose a noise distribution analysis-based despeckling method for OCT images. Specifically, we establish a noise model by dividing speckle noises into multiplicative and additive ones first, and then propose a two-step filtering mechanism, namely, augmented Lagrange function minimization and Rayleigh alpha-trimmed filtering (AR) method, to suppress such noises separately while maintain tissue microstructures. Simulations with both synthetic and practical OCT images are conducted to verify the effectiveness of the proposed AR method. Results show that the influence of multiplicative noises on OCT images are more significant, and the AR method is capable of suppressing both multiplicative and additive noises effectively, e.g. it improves the peak signal-to-noise ratio and structural similarity index measurements by 83.22

%

and 812.88

%

for typical retinal images, respectively, while retaining the important image structural details with less computational time.
Enhancement of terahertz fields generation on a silver surface under the effect of short-wavelength femtosecond pulses
Authors: Danilov E A , Uryupin S A
Published: May 2022

The pulse shape of low-frequency surface and quasi-cylindrical waves arising under the effect of a femtosecond pulse of laser radiation focused into a strip on a silver surface is studied. In silver, the effective electron collisions frequencies in the laser pulse field and in the low-frequency field may differ greatly. It is shown that for a large difference in the collision frequencies, conditions are possible when the field of surface wave exceeds the field of quasi-cylindrical wave, and the generation of low-frequency fields is mainly due to the inhomogeneous heating of electrons in the skin layer.
1.3 μm optically-pumped monolithic VCSEL based on GaAs with InGa(Al)As superlattice active region
Authors: Kryzhanovskaya Natalia V , Likhachev Alexey I , Blokhin Sergey A , Blokhin Alexey A , Pirogov Evgeniy V , Sobolev Maxim S , Babichev Andrey V , Gladyshev Andrey G , Karachinsky Leonid Ya , Novikov Innokenty I , Andryushkin Vladislav V , Denisov Dmitrii V , Egorov Anton Yu
Published: May 2022

Неre we report a monolitic long-wavelength vertical cavity surface-emitting laser based on GaAs with bottom GaAs/AlGaAs distributed Bragg reflectors (DBRs), metamorphic optical cavity with In0.41Ga0.59As/In0.25Ga0.75As-active region providing emission near 1.3 μm with high modal optical gain and top dielectric SiO2/Ta2O5 DBRs. We achieve continious wave single-mode operation at room temperature under optical pumping. The proposed approach has potential for high output power and high temperature (up to 200 °C) stable operation.
Candidate Eclipsing Binary Systems with a δ Scuti Star in Northern TESS Field
Authors: Kahraman Aliçavuş F. , Gümüş D. , Kırmızıtaş Ö. , Ekinci Ö. , Çavuş S. , Kaya Y. T. , Aliçavuş F.
Published: May 2022

The existence of pulsating stars in eclipsing binaries has been known for decades. These types of objects are extremely valuable systems for astronomical studies as they exhibit both eclipse and pulsation variations. The eclipsing binaries are the only way to directly measure the mass and radius of stars with a good accuracy (≤1%), while the pulsations are a unique way to probe the stellar interior via oscillation frequencies. There are different types of pulsating stars existing in eclipsing binaries. One of them is the δ Scuti variables. Currently, the known number of δ Scuti stars in eclipsing binaries is around 90 according to the latest catalog of these variables. An increasing number of these kinds of variables is important to understand the stellar structure, evolution and the effect of binarity on the pulsations. Therefore, in this study, we focus on discovering new eclipsing binaries with δ Scuti component(s). We searched within the northern Transiting Exoplanet Survey Satellite (TESS) field with a visual inspection by following some criteria such as light curve shape, the existence of pulsation like variations in the out-of-eclipse light curve and the T
eff values of the targets. As a result of these criteria, we discovered some targets. The orbital variations were first removed from the TESS light curves and frequency analysis was performed on the residuals. The luminosity, and absolute and bolometric magnitudes of the targets were calculated as well. To find how much of these parameters represent the primary (more luminous) binary component, we also computed the flux density ratio of the systems by utilizing the area of the eclipses. In addition, the positions of the systems in the H-R diagram were examined considering the flux density ratios. As a consequence of the investigation, we defined 38 candidate δ Scuti stars and also one Maia variable in eclipsing binary systems.
Epileptic electroencephalography classification using embedded dynamic mode decomposition
Authors: Hellar Jennifer , Erfanian Negar , Aazhang Behnaam
Published: May 2022

Objective. Seizure prediction devices for drug-resistant epileptic patients could lead to improved quality of life and new treatment options, but current approaches to classification of electroencephalography (EEG) segments for early identification of the pre-seizure state typically require many features and complex classifiers. We therefore propose a novel spatio-temporal EEG feature set that significantly aids in separation and easy classification of the interictal and preictal states. Approach. We derive key spectral features from the embedded dynamic mode decomposition (EmDMD) of the brain state system. This method linearizes the complex spatio-temporal dynamics of the system, describing the dynamics in terms of a spectral basis of modes and eigenvalues. The relative subband spectral power and mean phase locking values of these modes prove to be good indicators of the preictal state that precedes seizure onset. Main results. We analyze the linear separability and classification of preictal and interictal states based on our proposed features using seizure data extracted from the CHB-MIT scalp EEG and Kaggle American Epilepsy Society Seizure Prediction Challenge intracranial EEG databases. With a light-weight support vector machine or random forest classifier trained on these features, we classify the preictal state with a sensitivity of up to 92% and specificity of up to 89%. Significance. The EmDMD-derived features separate the preictal and interictal states, improving classification accuracy and motivating further work to incorporate them into seizure prediction algorithms.
Design of Memristor-based XOR Logic Gate and Half Adder
Authors: Su Kang , Li Tuo , Du Yanan , Yuan Xinxin , Liu Kai , Man Hongtao , Zou Xiaofeng
Published: May 2022

The non-volatile logic unit based on memristor can build a computing architecture which integrates processor and memory. A novel XOR logic gate as well as half adder with four memristors, one NMOS and one power excitation is proposed in this study. The constraints on the NMOS and power excitation are also presented. The effectiveness of the XOR logic gate proposed is confirmed by the simulation results of LTSPICE. Compared with several prior schemes, the design has better performance in terms of power consumption, operation steps and architecture complexity.
Digital Control System for Stepping Motor Driver Chip
Authors: Wang Song , Xin Xiaoning , Ren Jian , Guo Guofa
Published: May 2022

Stepper motor is a common execution unit in electromechanical control system. In order to realize the high precision and effective control of the stepper motor, a digital control scheme integrated in the stepping motor driver chip is proposed. On the ADMS platform, the digital control system is designed by Verilog HDL language, and the digital control system is connected with the H-bridge circuit. The control of the two-phase micro-stepping motor is realized by Eldo and Modelsim simulation. It can support SPI bus to set working mode, attenuation time, micro-stepping work mode and other parameters. The intelligent harmonic scheme can effectively reduce the ripple current, and the ripple current can be controlled. The control scheme adopts modular design, the coding is simple and easy, and has high application value.