bluuebunny/crossref_metadata_2025 huggingface dataset:
Prepulse inhibition vs cognitive modulation of the hand-blink reflex
Authors: Versace Viviana , Campostrini Stefania , Sebastianelli Luca , Saltuari Leopold , Valls-Solé Josep , Kofler Markus
Published: February 2021

The excitability of brainstem circuitries mediating defensive blinking in response to abrupt sensory inputs is continuously modulated by cortical areas, e.g., the hand-blink reflex (HBR), elicited by intense electrical median nerve stimulation, is enhanced when the stimulated hand is close to the face, with the behavioural purpose to optimize self-protection from increased threat. Here we investigated whether such cortically mediated HBR facilitation can be influenced by prepulse inhibition (PPI), which is known to occur entirely at the subcortical level. Twenty healthy volunteers underwent HBR recordings in five experimental conditions. In conditions 1 and 2, the stimulated hand was held either near (1) or far (2) from the face, respectively. In conditions 3 and 4, stimulation of the hand near the face was preceded by a peri-liminal prepulse to the index finger of the contralateral hand held either near (3) or far from the face (4). In condition 5, participants self-triggered the stimulus eliciting the HBR. We observed a reproducible HBR in 14 out of 20 participants and measured onset latency and area of the HBR in orbicularis oculi muscles bilaterally. HBR area decreased and latency increased in condition 2 relative to condition 1; HBR area decreased and latency increased markedly in condition 3, and somewhat less in condition 4, relative to conditions 1 and 2; self-stimulation (condition 5) also suppressed HBRs, but less than prepulses. These findings indicate that PPI of the HBR is more robust than the cognitive modulation exerted by top-down cortical projections. Possibly, an attentional shift to a prepulse may serve to reduce blinking in response to perturbation when it is convenient, in a given situation, not to interrupt ongoing visual processing.
Cohnella 1759 cysteine protease shows significant long term half-life and impressive increased activity in presence of some chemical reagents
Authors: Saghian Rayan , Mokhtari Elham , Aminzadeh Saeed
Published: February 2021

Thermostability and substrate specificity of proteases are major factors in their industrial applications. rEla is a novel recombinant cysteine protease obtained from a thermophilic bacterium,Cohnellasp.A01 (PTCC No: 1921). Herein, we were interested in recombinant production and characterization of the enzyme and finding the novel features in comparison with other well-studied cysteine proteases. The bioinformatics analysis showed that rEla is allosteric cysteine protease from DJ-1/ThiJ/PfpI superfamily. The enzyme was heterologously expressed and characterized and the recombinant enzyme molecular mass was 19.38 kD which seems to be smaller than most of the cysteine proteases. rEla exhibited acceptable activity in broad pH and temperature ranges. The optimum activity was observed at 50℃ and pH 8 and the enzyme showed remarkable stability by keeping 50% of residual activity after 100 days storage at room temperature. The enzyme Kmand Vmaxvalues were 21.93 mM, 8 U/ml, respectively. To the best of our knowledge,in comparison with the other characterized cysteine proteases, rEla is the only reported cysteine protease with collagen specificity. The enzymes activity increases up to 1.4 times in the presence of calcium ion (2 mM) suggesting it as the enzyme’s co-factor. When exposed to surfactants including Tween20, Tween80, Triton X-100 and SDS (1% and 4% v/v) the enzyme activity surprisingly increased up to 5 times.
Multi-cycle reversible control of gas permeability in thin film composite membranes via efficient UV-induced reactions
Authors: Alrayyes Abdalrahman U. , Low Ze-Xian , Wang Huanting , Saito Kei
Published: February 2021

This communication reports the use of light to reversibly constrict or ease the flow of oxygen through a very thin polymer coating. This is achievable by reversibly changing the polymer structure from a dense and rigid film to a loose and soft film.
A combination of heterogeneous catalysis and photocatalysis for the olefination of quinoxalin-2(1H)-ones with ketones in water: a green and efficient route to (Z)-enaminones
Authors: Xu Jun , Huang Lin , He Lei , Ni Zhigang , Shen Jiabin , Li Xiaoling , Chen Kaixian , Li Wanmei , Zhang Pengfei
Published: February 2021

This study describes a novel aqueous reaction for the synthesis of (Z)-enaminones through a combination of heterogeneous catalysis and photocatalysis.
Detection of sub-atomic movement in nanostructures
Authors: Liu Tongjun , Ou Jun-Yu , MacDonald Kevin F. , Zheludev Nikolay I.
Published: February 2021

Nanoscale objects move fast and oscillate billions of times per second. We introduce a methodology for detecting such movements, which is sensitive to displacements of sub-atomic amplitude.
Reactions of aryl dimethylphosphinothioate esters with anionic oxygen nucleophiles: transition state structure in 70% water–30% ethanol
Authors: Kalu Georgina I. , Ubochi Collins I. , Onyido Ikenna
Published: February 2021

Solvent stabilization of initial state (alongx,yaxis) leads to looser TS (vectorz).
Few-layer large Ti3C2Tx sheets exfoliated by NaHF2 and applied to the sodium-ion battery
Authors: Zhao Yan , Zhang Meng , Yan Hong , Feng Yu , Zhang Xinyu , Guo Ruijie
Published: February 2021

The first time to use NaHF2 aqueous solution to synthesize Ti3C2Tx, making Na+ ions intercalated between Ti3C2Tx layers, which has excellent thermal and structural stability and is a high-performance anode for sodium-ion battery.
Control of guest binding behavior of metal-containing host molecules by ligand exchange
Authors: Akine Shigehisa
Published: February 2021

Structural transformation driven by ligand exchange was effectively utilized to control the host–guest binding behavior of metal-containing host molecules.
Heteroatom-doped carbon materials with interconnected channels as ultrastable anodes for lithium/sodium ion batteries
Authors: Li Zhiqiang , Cai Le , Chu Kainian , Xu Shikai , Yao Ge , Wei Lingzhi , Zheng Fangcai
Published: February 2021

The resulting NOPCP exhibited excellent electrochemical performance for long-term lithium and sodium storage.
Luminescent cyclometalated platinum(ii) complexes with acyclic diaminocarbene ligands: structural, photophysical and biological properties
Authors: Martínez-Junquera Mónica , Lalinde Elena , Moreno M. Teresa , Alfaro-Arnedo Elvira , López Icíar P. , Larráyoz Ignacio M. , Pichel José G.
Published: February 2021

We report new cyclometalated Pt(ii) complexes bearing acyclic diaminocarbene (ADC) ligands, which feature competitive phosphorescence quantum yields, aggregation induced emission and cytotoxic activity towards tumor cell lines.
Vapor phase interfacial polymerization: a method to synthesize thin film composite membranes without using organic solvents
Authors: Paseta Lorena , Echaide-Górriz Carlos , Téllez Carlos , Coronas Joaquín
Published: February 2021

Thin film composite membranes of polyamide prepared by vapour phase interfacial polymerization between a diamine and an acyl chloride are applied to nanofiltration.
Highly improved electrochemical performances of LiCoO2via a multi-element co-doping strategy
Authors: Liao Xing-Qun , Ren Pan-Li , Zhang Chang-Ming , Yin Zhou-Lan , Liu Guo-Cong , Yu Jin-Gang
Published: February 2021

By using a combinatorial multi-element co-doping strategy, Ti/Mg/La were doped in Al-doped Co3O4 during the solid-phase sintering process, and the electrochemical performances of the developed LCO-D under high voltage were highly improved.
Temperature-programmed nitridation of monodispersed VOx nanoparticles into nanocrystalline superconducting oxygen-doped vanadium nitride
Authors: Dewangan Khemchand , Singh Dadan , Patel Sandeep Kumar Singh , Shrivas Kamlesh
Published: February 2021

A two-stage synthesis process was employed to prepare high-quality nanocrystalline vanadium nitride (VN) for superconducting applications.
Coronene: a high-voltage anion insertion and de-insertion cathode for potassium-ion batteries
Authors: Minami Kato , Masese Titus , Yoshii Kazuki
Published: February 2021

This work reports coronene, a high-voltage cathode material that manifests a high-voltage exceeding 4 V enkindled by anion (de)insertion.
Supersensitive CeOx-based nanocomposite sensor for the electrochemical detection of hydroxyl free radicals
Authors: Duanghathaipornsuk Surachet , Kim Dong-Shik , Phares Tamara L. , Li Cheng-Han , Jinschek Joerg R. , Alba-Rubio Ana C.
Published: February 2021

An electrochemical sensor comprised of cerium oxide nanoclusters grafted to a highly conductive carbon provided a limit of detection of 0.6 μM ˙OH and successfully detected in vitro the presence of ˙OH in preosteoblast cells from mouse bone tissue.
Continuous flow as an enabling technology: a fast and versatile entry to functionalized glyoxal derivatives
Authors: Lima Fabio , Meisenbach Mark , Schenkel Berthold , Sedelmeier Joerg
Published: February 2021

Continuous Flow methods to access glyoxal derivatives, which serve as valuable precursors for heterocyclic chemistry.
Comprehensive understanding of the structure-stacking property correlation to achieve high-performance ternary data-storage devices
Authors: Zhang Qi-jian , Cao Huan , Shen Jun-yu , Li Yang , Lu Jian-mei
Published: February 2021

Two small-molecule isomers with consistent functional units exhibit total different molecular stacking modes, rendering the memory behaviours from traditional binary memory to typical ternary memory.
Au decorated BiVO4 inverse opal for efficient visible light driven water oxidation
Authors: Wang Xiaonong , Li Xiaoxia , Low Jingxiang
Published: February 2021

Photocatalytic water splitting provides an effective way to prepare hydrogen and oxygen.
Low-cost and scalable carbon bread used as an efficient solar steam generator with high performance for water desalination and purification
Authors: Yang Yang , Zhao Man , Cao Zhen , Ge Zhen , Ma Yanfeng , Chen Yongsheng
Published: February 2021

Solar steam generation has been considered as a promising method for water desalination and purification.
Selective electrochemical reduction of CO2 to formic acid in a gas phase reactor with by-product recirculation
Authors: Thijs Barbara , Rongé Jan , Martens Johan A.
Published: February 2021

A reactor concept is proposed where recirculation of by-products such as H2 enhances the product selectivity of electrochemical CO2 reduction to formic acid.
Water vapor recovery device designed with interface local heating principle and its application in clean water production
Authors: Ge Bo , Tang Shaowang , Zhang Hao , Li Wenzhi , Wang Min , Ren Guina , Zhang Zhaozhu
Published: February 2021

The characteristic of the device is to realize the synchronization of sewage treatment and clean water production. The existence of superhydrophobic BiOBr layer selectively removes surface oil slick and degrades dissolved pollutants.
All-silicon metasurfaces for polarization multiplexed generation of terahertz photonic orbital angular momentum superposition states
Authors: Li Jie , Wang Guocui , Zheng Chenglong , Li Jitao , Yang Yue , Zhang Zhang , Yang Maosheng , Zhao Hongliang , Li Fuyu , Tang Tingting , Wu Liang , Li Jining , Zhang Yating , Zhang Yan , Yao Jianquan
Published: February 2021

The superposition state of photonic orbital angular momentum (OAM) has more degrees of freedom than pure photonic orbital angular momentum, with rich physical implications and engineering application possibilities.
A freeze-and-thaw-induced fragment of the microtubule-associated protein tau in rat brain extracts: implications for the biochemical assessment of neurotoxicity
Authors: Vasconcelos Israel C. , Campos Raquel M. , Schwaemmle Hanna K. , Masson Ana P. , Ferrari Gustavo D. , Alberici Luciane C. , Faça Vitor M. , Garcia-Cairasco Norberto , Sebollela Adriano
Published: February 2021

Tau is a microtubule-associated protein (MAP) responsible for controlling the stabilization of microtubules in neurons. Tau function is regulated by phosphorylation. However, in some neurological diseases Tau becomes aberrantly hyperphosphorylated, which contributes to the pathogenesis of neurological diseases, known as tauopathies. Western blotting (WB) has been widely employed to determine Tau levels in neurological disease models. However, Tau quantification by WB should be interpreted with care, as this approach has been recognized as prone to produce artifactual results if not properly performed. In the present study, our goal was to evaluate the influence of a freeze-and-thaw cycle, a common procedure preceding WB, to the integrity of Tau in brain homogenates from rats, 3xTg-AD mice and human samples. Homogenates were prepared in ice-cold RIPA buffer supplemented with protease/phosphatase inhibitors. Immediately after centrifugation, an aliquot of the extracts was analyzed via WB to quantify total and phosphorylated Tau levels. The remaining aliquots of the same extracts were stored for at least 2 weeks at either −20 or −80°C and then subjected to WB. Extracts from rodent brains submitted to freeze-and-thaw presented a ∼25 kDa fragment immunoreactive to anti-Tau antibodies. An in-gel digestion followed by mass spectrometry (MS) analysis in excised bands revealed this ∼25 kDa species corresponds to a Tau fragment. Freeze-and-thaw-induced Tau proteolysis was detected even when extracts were stored at −80°C. This phenomenon was not observed in human samples at any storage condition tested. Based on these findings, we strongly recommend the use of fresh extracts of brain samples in molecular analysis of Tau levels in rodents.
Review on DC transmission systems for integrating large‐scale offshore wind farms
Authors: Li Zhengxuan , Song Qiang , An Feng , Zhao Biao , Yu Zhanqing , Zeng Rong
Published: February 2021

The exploitation of offshore wind power has increased rapidly in recent years. To gain more wind power energy, offshore wind farms move farther from onshore. A comparison between HVAC and HVDC in terms of reliability, cost and transmission capability shows that HVDC is more suitable for long‐distance, high‐capacity bulk power transmission. However, the HVDC transmission for offshore wind power also faces great challenges because the offshore applications bring critical demands for low volume and low weight for the converters at the offshore side. On the other hand, the new topologies and conversion techniques of power electronic converters expedite many new DC transmission architectures for offshore wind power. Different HVDC architectures by using centralised voltage source converter (VSC), diode rectifier (DR), series‐connected wind turbine converters and all‐DC wind farm based on DC transformers are reviewed and compared. The advantages, challenges and development and application prospects for various DC transmission solutions are discussed.
Application of random matrix model in multiple abnormal sources detection and location based on PMU monitoring data in distribution network
Authors: Yan Yingjie , Liu Yadong , Fang Jian , Vijayakumar Pandi , Sanjeevikumar Padmanaban , Jiang Xiuchen
Published: February 2021

With the conversion of the global power economy and energy structure, access to a large amount of renewable energy has led to a decrease in power system inertia. The slight abnormal disturbance in the distribution network may have a significant impact on social and economic development. Aim at enhancing power stability and system resiliency; this study focuses on the detection and location of multiple abnormal sources in the distribution network. Most traditional methods use models relying on precise line parameters, subject to poor adaptability to the distribution network with a large number of nodes, and rapidly changing topology. Therefore, this study proposes a novel random matrix model, driven by monitoring data from phasor measurement units distributed on the overhead transmission lines. In this model, linear shrinkage (LS) theory, and Marchenko–Pastur law are combined for noise reduction to ensure the dynamic character and anti‐noise ability. Moreover, data dimensions and sample points may be at the same level in an extensive scale network. The LS and standard condition number rule (SCN) are used for estimating the number of abnormal sources. Finally, the effectiveness of this paper's model is verified in PSCAD. The results indicate that the method has specific dynamic performance and anti‐noise ability.
Decentralised power distribution and SOC management algorithm for the hybrid energy storage of shipboard integrated power system
Authors: Lin Yunfeng , Fu Lijun , Xiao Xiongbo
Published: February 2021

In the medium voltage direct current (MVDC) shipboard grid, the inherent inertial support from the DC capacitors is too small to resist step changes or fluctuations from the high power pulse load and propulsion load, which results in lower DC voltage quality. This study proposes a decentralised control algorithm for the MVDC shipboard hybrid energy storage system (HESS) to enhance the onboard survivability. This algorithm adjusts the droop control coefficient based on the bus voltage change rate adaptively, meanwhile the voltage differential signal processing and filtering are implemented by the trace differentiator. In addition, the proposed algorithm also has state‐of‐charge (SOC) balancing and SOC recovery abilities between multiple groups of energy storage devices. The parameter selection principle are analysed, and a variety of working conditions are simulated and verified in PSCAD. Theoretical analysis and simulation show that, HESS can achieve good power distribution and SOC management performance without communication compared to fixed droop coefficient control strategies, and the dynamic characteristics of bus voltage have been significantly improved.
Hybrid feature CNN model for point cloud classification and segmentation
Authors: Zhang Xinliang , Fu Chenlin , Zhao Yunji , Xu Xiaozhuo
Published: February 2021

This study proposes a hybrid feature convolutional neural network (HFCNN) model for the complete description of three‐dimensional (3D) point cloud features. The HFCNN confers sensitivity to the local, global, and single‐point properties simultaneously by a feature vector space expansion. Wherein, a pointwise convolutional network sub‐model realises the extraction of the local features by using a pointwise convolutional operator to process point cloud data directly. To consider the global properties of the point cloud, a central‐point radiation model is constructed as an input of the feature layer in a non‐network form. Meanwhile, the single‐point behaviour is characterised by the solo point coordinate information in the network. Within the constructed solo‐local‐global feature space, i.e. the fusion of single point feature, local feature and global feature, the HFCNN model can handle 3D point cloud data with unstructured and unordered properties. The HFCNN can be directly applied to the point cloud classification and segmentation without the modification of the CNN structure and training procedure. The experimental results have shown the effectiveness of the proposed model in prediction of class labels and point‐by‐point labels.
Intriguing detection of 12CO molecular emission in a classical Be star
Authors: Cochetti Y. R. , Arias M. L. , Kraus M. , Cidale L. S. , Torres A. F. , Granada A. , Maryeva O. V.
Published: February 2021

Context. In the group of B stars with spectroscopic peculiarities, we can find the Be and the B[e] stars. The Be stars are early-type rapid rotators that present, as their principal characteristic, emission lines of hydrogen and singly ionized metals due to the presence of a gaseous envelope. The B[e] stars present in their spectra heterogeneous features that reveal the presence of regions with very different properties in a gaseous and dusty envelope.

Aims. Our goal is to study the evolution of the disks around peculiar B stars through the variability of their physical properties and dynamical structure, as well as to set constraints on different models and disk forming mechanisms.

Methods. Throughout the last decade, we have carried out temporal monitoring of a sample of objects in the near infrared using spectroscopic facilities at the Gemini and Las Campanas Observatories. In the present work, we focus on the classical Be star 12 Vul, for which also optical spectra have been collected quasi-simultaneously.

Results. We observed variability in the hydrogen line profiles of 12 Vul, attributed to dissipating and building-up processes of the circumstellar envelope. Also, we found that this Be star presented the 12CO band heads in emission in one observation. The emission of this molecule has not been previously reported in a Be star, while it is a common feature among B[e] stars. We obtained parameters to describe the 12CO emitting region and propose different scenarios to explain this intriguing emission.
Cosmography by orthogonalized logarithmic polynomials
Authors: Bargiacchi G. , Risaliti G. , Benetti M. , Capozziello S. , Lusso E. , Saccardi A. , Signorini M.
Published: February 2021

Cosmography is a powerful tool for investigating the Universe kinematic and then for reconstructing the dynamics in a model-independent way. However, recent new measurements of supernovae Ia and quasars have populated the Hubble diagram up to high redshifts (z ∼ 7.5) and the application of the traditional cosmographic approach has become less straightforward due to the large redshifts implied. Here we investigate this issue through an expansion of the luminosity distance–redshift relation in terms of orthogonal logarithmic polynomials. In particular, we point out the advantages of a new procedure called orthogonalization, and we show that such an expansion provides a very good fit in the whole z = 0 ÷ 7.5 range to both real and mock data obtained assuming various cosmological models. Moreover, although the cosmographic series is tested well beyond its convergence radius, the parameters obtained expanding the luminosity distance–redshift relation for the Lambda cold dark matter (ΛCDM) model are broadly consistent with the results from a fit of mock data obtained with the same cosmological model. This provides a method for testing the reliability of a cosmographic function to study cosmological models at high redshifts, and it demonstrates that the logarithmic polynomial series can be used to test the consistency of the ΛCDM model with the current Hubble diagram of quasars and supernovae Ia. We confirm a strong tension (at > 4σ) between the concordance cosmological model and the Hubble diagram at z > 1.5. This tension is dominated by the contribution of quasars at z > 2 and also starts to be present in the few supernovae Ia observed at z > 1.
Application of the noise annoyance equivalents model for aircraft, rail and road traffic noise to self-reported sleep disturbance
Authors: Lechner Christoph , Schnaiter David , Bose-O’Reilly Stephan
Published: February 2021

Sleep disturbances caused by noise exposure are the most relevant outcome measured in disability adjusted life years (DALYs). In analogy to the combined effects of noise from multiple sources on annoyance, these are also of interest for sleep disorders. The study “Overall Noise Assessment” Innsbruck examined data from 1031 personal interviews. Aircraft, rail and road noise were correlated. To choose participants combined exposures were clustered into small, medium and severely affected living situations. The effect of demographic features, noise sensitivity, access to a silent façade and other factors on self-reported sleep disturbances was investigated applying bivariate analyses. Exposure-response curves and their 95% confidence intervals with cut-off values of 72% for “highly disturbed sleep” were generated and the results were discussed in comparison to recently published curves. Using source-specific exposure-response relationships, an overall model for evaluating sleep disorders was developed based on the “annoyance equivalents model”. The “total sleep disturbance response” shows an accumulative outcome for each source measured. A protective effect of road traffic noise as background noise for air and railroad sources could not be proven. Both the “Total Sleep Disruption Assessment Model” and the “Dominant Source Model” have a Spearman-Rho of 0.3 and are therefore suitable for use in noise assessment.
The limits of institutionalizing predominance: understanding the emergence of Turkey’s new opposition
Authors: Aras Bülent , Helms Ludger
Published: February 2021

This article offers an institutionalist assessment of the more recent chapters of political opposition in Erdoğan’s Turkey. There is good reason to suppose that the institutional features of a given regime can explain the performance of opposition parties to a significant extent. That said, the case of Turkey provides impressive evidence that there are striking limits to institutionalizing political predominance, to undermining political oppositions by institutional means, and to explaining the performance of opposition parties with the prevailing institutional resources and constraints. Specifically, attempts at institutionalizing a predominant power status carry particular risks of generating inverse effects, including increased political vulnerability. However, there are no automatic effects. Rather, as the Turkish experience suggests, reasonably vigorous actors to become politically relevant must seize the particular (if usually limited) opportunities arising from advanced institutional autocratization.
Existence of attractors for stochastic diffusion equations with fractional damping and time-varying delay
Authors: Chen Pengyu , Zhang Xuping
Published: February 2021

This paper deals with the well-posedness and existence of attractors of a class of stochastic diffusion equations with fractional damping and time-varying delay on unbounded domains. We first prove the well-posedness and the existence of a continuous non-autonomous cocycle for the equations and the uniform estimates of solutions and the derivative of the solution operators with respect to the time-varying delay. We then show pullback asymptotic compactness of solutions and the existence of random attractors by utilizing the Arzelà–Ascoli theorem and the uniform estimates for the derivative of the solution operator in the fractional Sobolev space Hα(Rn), with 0 < α < 1.
Electroresistance effect in MoS2-Hf0.5Zr0.5O2 heterojunctions
Authors: Chaudhary P. , Buragohain P. , Kozodaev M. , Zarubin S. , Mikheev V. , Chouprik A. , Lipatov A. , Sinitskii A. , Zenkevich A. , Gruverman A.
Published: February 2021

Pairing two-dimensional semiconductors with ferroelectric films may allow for the development of hybrid electronic devices that would not only exhibit a combination of the functional properties of both material groups but would also reveal unusual characteristics emerging from coupling between these properties. Here, we report the observation of a considerable (up to 103 at 0.8 V read bias) polarization-mediated tunneling electroresistance (TER) effect in Hf0.5Zr0.5O2 (HZO) ferroelectric tunnel junctions (FTJs) employing MoS2 as one of the electrodes. It was found that for this type of hybrid FTJs, a change in resistance upon polarization reversal could be described by Fowler–Nordheim tunneling. The underlying mechanism for the enhanced TER effect is a polarization-mediated accumulation or depletion of the majority carriers at the MoS2/HZO interface, which results in a change in the effective barrier shape seen by the tunneling electrons. Given the compatibility of HfO2-family ferroelectrics with CMOS technology and a possibility of large scale growth and transfer of MoS2 films, our results provide a pathway for fabrication of high-density nonvolatile memory and data storage systems based on hybrid FTJs.
The properties and prospects of chemically exfoliated nanosheets for quantum materials in two dimensions
Authors: Song Xiaoyu , Yuan Fang , Schoop Leslie M.
Published: February 2021

The aim of this review is to elucidate the potential of chemically exfoliated sheets for the field of quantum matter. Quantum materials are loosely defined as materials that do not follow the laws of classical physics; the family commonly includes complex magnets, topological materials, or superconductors. Two-dimensional (2D) materials have been key in driving the field of quantum matter forward due to the high degree of tunability they offer. However, progress has largely been made with mechanically exfoliated sheets while chemically exfoliated sheets have been mostly ignored. The latter offer a wide range of advantages, for example, chemical exfoliation gives access to 2D materials that are unobtainable with other methods. In this review, we highlight the progress that has been made in exploring properties that can be associated with quantum materials of chemically exfoliated nanosheets. We will cover magnetic chemically exfoliated sheets, their use in transistors, their potential as 2D topological insulators, and opportunities that arise for the emerging field of twistronics. We will highlight both the advantages and current shortcomings of chemically exfoliated quantum materials and address how shortcomings might be overcome in the future. We conclude that while the prospects of chemically exfoliated sheets for quantum materials are still underexplored, they offer a large potential for having an impact in that field.
Convolutional neural network and long short-term memory based reduced order surrogate for minimal turbulent channel flow
Authors: Nakamura Taichi , Fukami Kai , Hasegawa Kazuto , Nabae Yusuke , Fukagata Koji
Published: February 2021

We investigate the applicability of the machine learning based reduced order model (ML-ROM) to three-dimensional complex flows. As an example, we consider a turbulent channel flow at the friction Reynolds number of Reτ=110 in a minimum domain, which can maintain coherent structures of turbulence. Training datasets are prepared by direct numerical simulation (DNS). The present ML-ROM is constructed by combining a three-dimensional convolutional neural network autoencoder (CNN-AE) and a long short-term memory (LSTM). The CNN-AE works to map high-dimensional flow fields into a low-dimensional latent space. The LSTM is, then, utilized to predict a temporal evolution of the latent vectors obtained by the CNN-AE. The combination of the CNN-AE and LSTM can represent the spatiotemporal high-dimensional dynamics of flow fields by only integrating the temporal evolution of the low-dimensional latent dynamics. The turbulent flow fields reproduced by the present ML-ROM show statistical agreement with the reference DNS data in time-ensemble sense, which can also be found through an orbit-based analysis. Influences of the population of vortical structures contained in the domain and the time interval used for temporal prediction on the ML-ROM performance are also investigated. The potential and limitation of the present ML-ROM for turbulence analysis are discussed at the end of our presentation.
Stationary cross-flow breakdown in a high-speed swept-wing boundary layer
Authors: Chen Jianqiang , Dong Siwei , Chen Xi , Yuan Xianxu , Xu Guoliang
Published: February 2021

A new type-II secondary instability mode was recently identified in high-speed cross-flows using stability analysis, but its role in the transition process is not yet clear. Here, the breakdown of stationary cross-flow vortices at high speeds is examined using direct numerical simulation to determine differences from the low-speed case. The transition is achieved by disturbing stationary cross-flow vortices with unsteady blowing/suction in a swept-wing boundary layer with swept angle 45°, free-stream Mach number 6, and unit Reynolds number 8 ×106. The results reveal that, as in low-speed cases, the type-I secondary instability mode (with frequency ≈190 kHz) is crucial to the breakdown, but neither the traditional nor the new type-II secondary instability play a role. The vortical structure induced by the type-I secondary instability mode has two counter-rotating tubes stretched along the spanwise direction and a footprint aligned normal to the mean flow direction. The composite vortex structures are similar to rolls/braids in plane free-shear layers arising from Kelvin–Helmholtz instability and they evolve into hairpins in the late stage of the transition. Some preliminary statistics from a three-dimensional turbulent boundary layer are provided as a comparison to the two-dimensional ones. The fluctuating cross-flow velocity does not contribute to the momentum and heat transfer on average, probably due to the very weak mean cross-flow profile. Thus, the obtained three-dimensional turbulent boundary layer is the same as the two-dimensional one but inclined by a swept angle. To the authors’ knowledge, this is the first in-depth analysis of the high-speed cross-flow transition to full turbulence.
Hohlraum x-ray preheat asymmetry measurement at the ICF capsule via Mo ball fluorescence imaging
Authors: Dewald E. L. , Landen O. L. , Salmonson J. , Masse L. , Smalyuk V. A. , Schneider M. , Nikroo A.
Published: February 2021

In inertial confinement fusion, penetrating asymmetric hohlraum preheat radiation (>1.8 keV, which includes high temperature coronal M-band emission from laser spots) can lead to asymmetric ablation front and ablator–fuel interface hydrodynamic instability growth in the imploding capsule. First experiments to infer the preheat asymmetries at the capsule were performed on the National Ignition Facility for high density carbon (HDC) capsules in low density fill (0.3 mg/cc 4He) Au hohlraums by time resolved imaging of 2.3 keV fluorescence emission of a smaller Mo sphere placed inside the capsule. Measured Mo emission is pole hot (P2 > 0) since M-band is generated mainly by the outer laser beams as their irradiance at the hohlraum wall is 5× higher than for the inner beams. P2 has a large swing vs time, giving insight into the laser heated hohlraum dynamics. P4 asymmetry is small at the sphere due to efficient geometric smoothing of hohlraum P4 asymmetries at large hohlraum-to-capsule radii ratios. The asymmetry at the HDC capsule is inferred from the Mo emission asymmetry accounting for the Mo/HDC radius difference and HDC capsule opacity.
Quasi-2D bromide perovskite nanocrystals with narrow phase distribution prepared using ternary organic cations for sky-blue light-emitting diodes
Authors: Zhang Huijun , Li Wei , Zhang Xue , Yu Cong , Li Teng , Zhang Xiaoshuai , Gao Zhaodongfang , Xiong Chuanxi , Wang Tao
Published: February 2021

Quasi-2D perovskite semiconductors can be created by introducing organic interlayer cations into 3D perovskites and possess large binding energy, superior stability, high luminance efficiency, and tunable bandgap, holding promising applications in blue-light emitting devices. Compared with mixed halide perovskites, quasi-2D bromide perovskites emit blue light with high color stability. However, multiple-phases usually co-exist in quasi-2D bromide perovskites, resulting in low color purity. In this work, three ammonium bromides, namely, 3-(trifluoromethyl)phenyltrimethylammonium bromide (F-PTABr), benzyltributylammonium bromide (BTBABr), and phenethylammonium bromide (PEABr), are employed to fabricate quasi-2D perovskite films with narrow phase distribution. PEA serves as the scaffold to stabilize the quasi-2D PEA2Csn-1PbnBr3n+1 perovskite structure and provides enough space to allow the F-PTA cation entering the interlayer, which further triggers the entrance of a larger BTBA cation into the interlayer. The large F-PTA and BTBA cations reduce the crystal size of the perovskite and narrow the phase distribution to n = 2. As a result, the photoluminescence spectrum of the PEA0.9F-PTA0.05BTBA0.05-based perovskite film becomes unimodal and blue-shifts from 498 to 484 nm compared with the film using the PEA1.0 cation. A sky-blue light-emitting diode with an external quantum efficiency of 0.6% is achieved using the PEA0.9F-PTA0.05BTBA0.05-based perovskite as the emitter. We, therefore, demonstrate a strategy to prepare phase narrow quasi-2D perovskites with improved color purity by introducing ternary organic cations into the quasi-2D perovskites and envisage that promising device performance can be achieved with a further dedicated structure design of the ammonium cations.
Translating additive connectors from English into Spanish and vice versa
Authors: Labrador Belén
Published: February 2021

This contrastive study aims to analyze and compare the usages of one type of sentence connectors, reinforcing additive connectors, in English and in Spanish through a corpus-based approach, which relies on bidirectional translation data. The analysis includes behavioral profiles of each of the list of connectors in each language, comparisons among them, comparisons between original texts and translated texts in both directions, cross-register differences, translational options, and the connectors’ mutual correspondence, which shows the degree of equivalence of each pair of connectors based on how often they are translated into each other. The results show important differences in the use of reinforcing additive connectors, mainly connected with (a) the more even distribution in English as compared with the great predominance of one connector in Spanish,además; (b) a more marked tendency for explicitation in Spanish and for the use of zero translation in English; (c) generally low mutual correspondence values, which seem to reflect high language variation, richness, and complex mapping of resources utilized to connect sentences.
NK/ILC1 cells mediate neuroinflammation and brain pathology following congenital CMV infection
Authors: Kveštak Daria , Juranić Lisnić Vanda , Lisnić Berislav , Tomac Jelena , Golemac Mijo , Brizić Ilija , Indenbirken Daniela , Cokarić Brdovčak Maja , Bernardini Giovanni , Krstanović Fran , Rožmanić Carmen , Grundhoff Adam , Krmpotić Astrid , Britt William J. , Jonjić Stipan
Published: February 2021

Congenital human cytomegalovirus (cHCMV) infection of the brain is associated with a wide range of neurocognitive sequelae. Using infection of newborn mice with mouse cytomegalovirus (MCMV) as a reliable model that recapitulates many aspects of cHCMV infection, including disseminated infection, CNS infection, altered neurodevelopment, and sensorineural hearing loss, we have previously shown that mitigation of inflammation prevented alterations in cerebellar development, suggesting that host inflammatory factors are key drivers of neurodevelopmental defects. Here, we show that MCMV infection causes a dramatic increase in the expression of the microglia-derived chemokines CXCL9/CXCL10, which recruit NK and ILC1 cells into the brain in a CXCR3-dependent manner. Surprisingly, brain-infiltrating innate immune cells not only were unable to control virus infection in the brain but also orchestrated pathological inflammatory responses, which lead to delays in cerebellar morphogenesis. Our results identify NK and ILC1 cells as the major mediators of immunopathology in response to virus infection in the developing CNS, which can be prevented by anti–IFN-γ antibodies.
A wireless passive pressure sensor using microstructured ferromagnetic films with tunable effective permeability
Authors: Lin Y-C , Cai M-X , Yang Y-J
Published: February 2021

This paper presents a novel LC-based passive wireless flexible pressure sensor that employs microstructured ferromagnetic films with tunable effective permeability. The proposed device consists of a micromachined planar spiral coil and a polymer film with cilia arrays (CAs) realized by the ferrofluidic instability principle. The effective permeability of the polymer film can be tuned by deforming the CAs with externally applied pressure, which can be estimated in turn by detecting the resonant frequency of the device using the phase-dip technique. The fabrication parameters for synthesizing different dimensions and densities of CAs were investigated as well. Devices of different CA densities were measured and discussed. The measured results showed that the device quality factor and phase change both increased with applied pressure. Due to this characteristic, the proposed device is advantageous over typical capacitive LC-based devices and performs better in wireless interrogation while maintaining the sensitivity of pressure sensing.
Tunable plasmonic resonator using conductivity modulated Bragg reflectors
Authors: Pathiranage Sachinthana , Gunapala Sarath D , Premaratne Malin
Published: February 2021

We design a tunable plasmonic resonator that may have applications in sensing and plasmon generation—our design uses graphene-based Bragg reflectors of periodically modulated conductivity. Specifically, we explore and utilize the ability to use an array of Gaussian conductivity gratings as fully reflecting mirrors for surface plasmon polaritons (SPPs) propagating along a two-dimensional graphene sheet sandwiched between two dielectric materials. Graphene supports SPPs in the near-infrared to terahertz (THz) regime of the electromagnetic spectrum compared to those observed in metal-dielectric systems. Our resonator is fundamentally different from other similar published resonator designs because the distributed reflectors provide light confinement in both the horizontal and the vertical directions. As a result, the resonator is compact in the vertical-direction as we no longer use traditional mirrors or dielectric assisted gratings. Besides, conventional resonator designs only support a single, fixed resonant frequency, set by the mirror reflectivity and the cavity material’s properties. The versatility of graphene is that its Fermi energy can be electrically varied, thus allowing us to change the peak reflectivity of the graphene Bragg-grating without physically changing its physical dimensions. Therefore, by varying the Bragg wavelength, we can shift the resonance frequency of the cavity. One use of our resonator is in plasmonic lasers. We illustrate this use by analyzing the resonator parameters such as the linewidth and the quality factor of the plasmonic resonator.
Self-calibration of a variable-line-spacing grating for an absolute optical encoder with a Fizeau interferometer
Authors: Xiong Xin , Quan Lue , Shimizu Yuki , Matsukuma Hiraku , Gao Wei
Published: February 2021

The principle of the self-calibration method for the evaluation of a planar scale grating having a constant pitch is extended to realize the evaluation of the pitch distribution of a planar scale grating having variable line spacings (VLSs) along the X- and Y-directions. In the conventional self-calibration method, the wavefronts in the zeroth-order diffracted beam and the first-order diffracted beams observed by a Fizeau interferometer arranged in the Littrow configuration were employed to evaluate the pitch deviation of a scale grating. The arithmetic operation with the wavefront data realizes the evaluation of the pitch deviation over a large area in a short time, while cancelling the influence of the out-of-flatness of a scale grating. Meanwhile, theoretical equations in the conventional self-calibration method cannot be directly applied to the evaluation of a VLS grating due to its unique properties of the pitch distribution. In this paper, major modifications are thus made to the conventional theoretical equations for deriving the pitch distribution of a VLS grating. To verify the performance of the newly proposed method, the pitch distribution of a VLS grating employed in a commercial planar absolute encoder is evaluated in experiments.
A review on factors that affect surface charge accumulation and charge-induced surface flashover
Authors: Yuan Mengqiang , Zou Liang , Li Zongze , Pang Long , Zhao Tong , Zhang Li , Zhou Jierui , Xiao Peng , Akram Shakeel , Wang Zezhong , He Shun
Published: February 2021

The surface charge accumulation is very likely to trigger the surface flashover, which limits the large-scale application of DC GIL/GIS. This article comprehensively reviews the effect of six factors, including insulator-electrode shape, surface roughness of the insulator and conductor, metal particles, temperature, humidity, and gas type, on the insulator surface charging property. Furthermore, three models i.e. ‘analogous ineffective region’ expansion model, charge cluster triggered surface flashover model, and synergistic model of adsorbed gas, revealing the mechanism of charge triggered surface flashover phenomenon are reviewed and discussed. Future work from the perspective of theoretical analysis and engineering application are suggested in this field.
Bimetallic oxygen electrocatalyst derived from metallocenes doped MOFs
Authors: Cheng Guojie , Wu Guangyao , Li Han , Liu Shucheng , Liu Yi
Published: February 2021

Herein, metallocens (ferrocene, ruthenocene and cobaltocene) were in situ hybridized with two dimensional metal-organic frameworks (MOFs) via an improved inter-diffusion approach. The metallocens@MOFs hybrids were direct carbonized and transformed to Fe(Ru,Co)–Co@C composites. These bimetallic electrocatalysts show remarkable oxygen evolution reaction (OER) activity by taking advantage of the synergetic effect between the binary metals. Among of them, the obtained Fe–Co@C exhibits lower overpotential (320 mV at 10 mA cm−2) and satisfactory stability toward OER. The study presents a novel and facile strategy to synthesize low-cost bimetallic catalyst, showing great promise in electrocatalysis of oxygen.
The size effect in adhesive contact on a gradient nanostructured coating
Authors: Li Peixing , Liu Tie-Jun
Published: February 2021

The adhesive contact problem between a rigid cylindrical punch and a gradient nanostructured (GNS) coating is investigated by considering the size effect. The laminated plate model is applied to characterize the material properties of a GNS coating in plane strain couple stress elasticity. By using the Fourier integral transform and transfer matrix method, the governing integral equation(s) for the two-dimensional adhesive contact problem are obtained. Numerically calculated results are presented to analyse the effect of characteristic material length, the adhesion parameter and nonhomogeneous parameters on the mechanical response of the GNS coating for the adhesive contact problem. We explore the nanoscale contact of a GNS coating with shear modulus varying as a function of depth according to an exponential function or the power-law function. The present results provide a way to improve the contact deformation and damage to nanoelectromechanical systems by adjusting the gradient index of the GNS coating.