bluuebunny/crossref_metadata_2025 huggingface dataset:
The Clotting Trigger Is an Important Determinant for the Coagulation Pathway In Vivo or In Vitro—Inference from Data Review
Authors: He Shu , Cao Honglie , Thålin Charlotte , Svensson Jan , Blombäck Margareta , Wallén Håkan
Published: December 2020

Blood coagulation comprises a series of enzymatic reactions leading to thrombin generation and fibrin formation. This process is commonly illustrated in a waterfall-like manner, referred to as the coagulation cascade. In vivo, this “cascade” is initiated through the tissue factor (TF) pathway, once subendothelial TF is exposed and bound to coagulation factor VII (FVII) in blood. In vitro, a diminutive concentration of recombinant TF (rTF) is used as a clotting trigger in various global hemostasis assays such as the calibrated automated thrombogram, methods that assess fibrin turbidity and fibrin viscoelasticity tests such as rotational thromboelastometry. These assays aim to mimic in vivo global coagulation, and are useful in assessing hyper-/hypocoagulable disorders or monitoring therapies with hemostatic agents. An excess of rTF, a sufficient amount of negatively charged surfaces, various concentrations of exogenous thrombin, recombinant activated FVII, or recombinant activated FIXa are also used to initiate activation of specific sub-processes of the coagulation cascade in vitro. These approaches offer important information on certain specific coagulation pathways, while alterations in pro-/anticoagulants not participating in these pathways remain undetectable by these methods. Reviewing available data, we sought to enhance our knowledge of how choice of clotting trigger affects the outcome of hemostasis assays, and address the call for further investigations on this topic.
Spectroscopic study of the TbAl3(BO3)4 single crystal: Raman and luminescence spectroscopy
Authors: Peschanskii A. V. , Glamazda A. Yu. , Gudim I. A.
Published: December 2020

The vibrational and luminescence properties of the TbAl3(BO3)4 single crystal were studied in the temperature range of 5–300 K. Raman spectra of the single crystal revealed 5 of 7 A1 and all E phonon modes predicted by the group-theory analysis. The splitting energy between the LO and TO components of polar E phonons is determined. A group of intense bands associated with the 5D4 → 7F0 electronic transition was observed in the energy range of 14520–14680 cm−1 of the luminescence spectra. The intensity of these bands decreases upon heating. At the same time, the bands which can be assigned with 5D4 → 7F6, 5D4 → 7F5, and 5D4 → 7F4 transitions were revealed in luminescence spectra at room temperature. The intensity of these bands is comparable to the intensity of the Raman spectrum of TbAl3(BO3)4. The observation of luminescence from the 5D4 multiplet (20600–20750 cm−1) upon excitation at λexc = 632.8 nm (15803 cm−1) and λexc = 532 nm (18797 cm−1) indicates strong nonlinear properties of the studied crystal. The structure of the main 7F6 multiplet of Tb+3 in the TbAl3(BO3)4 single crystal has been studied at 5 K by Raman spectroscopy. The energies of the electronic levels of 7F6 and 5D4 multiplets were determined from the luminescence spectra measured at 300 K.
Requirements for very high temperature Kohn–Sham DFT simulations and how to bypass them
Authors: Blanchet A. , Torrent M. , Clérouin J.
Published: December 2020

In high-temperature density functional theory simulations (from tens of eV to keV), the total number of Kohn–Sham orbitals is a critical quantity to get accurate results. To establish the relationship between the number of orbitals and the level of occupation of the highest energy orbital, we derived a model based on the homogeneous electron gas properties at finite temperature. This model predicts the total number of orbitals required to reach a given level of occupation and, thus, a stipulated precision. Levels of occupation as low as 10−4, and below, must be considered to get converged results better than 1%, making high-temperature simulations very time consuming beyond a few tens of eV. After assessing the predictions of the model against previous results and Abinit minimizations, we show how the extended FPMD method of Zhang et al. [Phys. Plasmas 23, 042707 (2016)] allows us to bypass these strong constraints on the number of orbitals at high temperature.
Synthesis of lossless electric circuits based on prescribed Jordan forms
Authors: Figotin Alexander
Published: December 2020

We advance here an algorithm of the synthesis of lossless electric circuits such that their evolution matrices have the prescribed Jordan canonical forms subject to natural constraints. Every synthesized circuit consists of a chain-like sequence of LC-loops coupled by gyrators. All involved capacitances, inductances, and gyrator resistances are either positive or negative with values determined by explicit formulas. A circuit must have at least one negative capacitance or inductance for having a nontrivial Jordan block for the relevant matrix.
Scintillator detector characterization for laser-driven proton beam imaging
Authors: Tang H. , Russell B. K. , Maksimchuk A. , Campbell P. T. , Manuel M. J.-E. , Willingale L.
Published: December 2020

The spatial resolution and imaging characteristics of plastic scintillators are characterized using laser-driven proton beams. Laser-driven proton beams typically have broad energy spectra and are accompanied by relativistic electrons and high-energy photons, both potentially contributing to background noise. Different types and thicknesses of Eljen Technology scintillators are compared to determine their intrinsic point spread function. Point-projection imaging of a mesh is used to compare the imaging resolution of the scintillator to the usual imaging detector, radiochromic film, and is found to be reasonably comparable and sufficient for many experimental applications.
Scaling the vorticity dynamics in the leading-edge vortices of revolving wings with two directional length scales
Authors: Werner Nathaniel H. , Wang Junshi , Dong Haibo , Panah Azar Eslam , Cheng Bo
Published: December 2020

In revolving or flapping wings, radial planetary vorticity tilting (PVTr) is a mechanism that contributes to the removal of radial (spanwise) vorticity within the leading-edge vortex (LEV), while vorticity advection increases its strength. Dimensional analysis predicts that the PVTr and advection should scale with the wing aspect-ratio (AR) in identical fashion, assuming a uniform characteristic length is used. However, the authors’ previous work suggests that the vorticity advection decreases more rapidly than the PVTr as AR increases, indicating that separate normalizations should be applied. Here, we aim to develop a comprehensive scaling for the PVTr and vorticity advection based on simulation results using computational fluid dynamics. Two sets of simulations of revolving rectangular wings at an angle of attack of 45° were performed, the first set with the wing-tip velocity maintained constant, so that the Reynolds number (Re) defined at the radius of gyration equals 110, and the second set with the wing angular velocity maintained constant, so that Re defined at one chord length equals 63.5. We proposed two independent length scales based on LEV geometry, i.e., wing-span for the radial and tangential directions and wing chord for the vertical direction. The LEV size in the radial and tangential directions was limited by the wing-span, while the vertical depth remained invariant. The use of two length scales successfully predicted not only the scaling for the PVTr and the vorticity advection but also the relative magnitude of advection in three directions, i.e., tangential advection was strongest, followed by the vertical (downwash) and then the radial that was negligible.
Nanoscale control of LaAlO3/SrTiO3 metal–insulator transition using ultra-low-voltage electron-beam lithography
Authors: Yang Dengyu , Hao Shan , Chen Jun , Guo Qing , Yu Muqing , Hu Yang , Eom Kitae , Lee Jung-Woo , Eom Chang-Beom , Irvin Patrick , Levy Jeremy
Published: December 2020

We describe a method to control the insulator–metal transition at the LaAlO3/SrTiO3 interface using ultra-low-voltage electron beam lithography. Compared to previous reports that utilize conductive atomic force microscope (c-AFM) lithography, this approach can provide comparable resolution (∼10 nm) at write speeds (10 mm/s) that are up to 10 000× faster than c-AFM. The writing technique is nondestructive, and the conductive state is reversible via prolonged exposure to air. Transport properties of representative devices are measured at milli-Kelvin temperatures, where superconducting behavior is observed. We also demonstrate the ability to create conducting devices on graphene/LaAlO3/SrTiO3 heterostructures. The underlying mechanism is believed to be closely related to the same mechanism regulating c-AFM-based methods.
A comparison of experimental and theoretical low energy positron scattering from furan
Authors: Cheong Z. , Moreira G. M. , Bettega M. H. F. , Blanco F. , Garcia G. , Brunger M. J. , White R. D. , Sullivan J. P.
Published: December 2020

This paper presents a joint experimental and theoretical study of positron scattering from furan. Experimental data were measured using the low energy positron beamline located at the Australian National University and cover an energy range from 1 eV to 30 eV. Cross sections were measured for total scattering, total elastic and inelastic scattering, positronium formation, and differential elastic scattering. Two theoretical approaches are presented: the Schwinger multichannel method and the independent atom method with screening corrected additivity rule. In addition, our data are compared to corresponding electron scattering results from the same target with a number of significant differences observed and discussed.
Accurate ground state potential of Cu2 up to the dissociation limit by perturbation assisted double-resonant four-wave mixing
Authors: Bornhauser P. , Beck M. , Zhang Q. , Knopp G. , Marquardt R. , Gourlaouen C. , Radi P. P.
Published: December 2020

Perturbation facilitated double-resonant four-wave mixing is applied to access high-lying vibrational levels of the X 1Σg+ (0g+) ground state of Cu2. Rotationally resolved transitions up to v″ = 102 are measured. The highest observed level is at 98% of the dissociation energy. The range and accuracy of previous measurements are significantly extended. By applying the near dissociation equation developed by Le Roy [R. J. Le Roy, J. Quant. Spectrosc. Radiat. Transfer 186, 197 (2017)], a dissociation energy of De = 16 270(7) hc cm−1 is determined, and an accurate potential energy function for the X 1Σg+ (0g+) ground state is obtained. Molecular constants are determined from the measured transitions and by solving the radial Schrödinger equation using this function and are compared with results from earlier measurements. In addition, benchmark multi-reference configuration interaction computations are performed using the Douglas–Kroll–Hess Hamiltonian and the appropriate basis of augmented valence quadruple ζ type. Coupled-cluster single, double, and perturbative triple calculations were performed for comparison.
Breaking symmetries of the reservoir equations in echo state networks
Authors: Herteux Joschka , Räth Christoph
Published: December 2020

Reservoir computing has repeatedly been shown to be extremely successful in the prediction of nonlinear time-series. However, there is no complete understanding of the proper design of a reservoir yet. We find that the simplest popular setup has a harmful symmetry, which leads to the prediction of what we call mirror-attractor. We prove this analytically. Similar problems can arise in a general context, and we use them to explain the success or failure of some designs. The symmetry is a direct consequence of the hyperbolic tangent activation function. Furthermore, four ways to break the symmetry are compared numerically: A bias in the output, a shift in the input, a quadratic term in the readout, and a mixture of even and odd activation functions. First, we test their susceptibility to the mirror-attractor. Second, we evaluate their performance on the task of predicting Lorenz data with the mean shifted to zero. The short-time prediction is measured with the forecast horizon while the largest Lyapunov exponent and the correlation dimension are used to represent the climate. Finally, the same analysis is repeated on a combined dataset of the Lorenz attractor and the Halvorsen attractor, which we designed to reveal potential problems with symmetry. We find that all methods except the output bias are able to fully break the symmetry with input shift and quadratic readout performing the best overall.
Modeling the agglomeration of settling particles in a dewatering process
Authors: Rahmat Amin , Weston Daniel , Madden Daniel , Usher Shane , Barigou Mostafa , Alexiadis Alessio
Published: December 2020

In this study, the agglomeration of settling particles in a dewatering process is studied numerically. The numerical model is based on the smoothed particle hydrodynamic method. The interaction between solid particles is governed by the Lennard-Jones potential. This paper presents a systematic study for evaluating the influence of various important parameters on the dewatering process, i.e., the Reynolds number, inter-particle pair potential, and phase loading. Several quantitative parameters are introduced to characterize the structure and behavior of agglomerates. It is observed that based on the interplay between the Reynolds number and the pair potential, the agglomerates form four different structures.
Purcell-enhanced single-photon emission from a strain-tunable quantum dot in a cavity-waveguide device
Authors: Hepp Stefan , Hornung Florian , Bauer Stephanie , Hesselmeier Erik , Yuan Xueyong , Jetter Michael , Portalupi Simone L. , Rastelli Armando , Michler Peter
Published: December 2020

On-chip quantum photonics is a promising route toward the implementation of complex photonic architectures on a small footprint. Therefore, different photonic components demonstrated for off-chip operation must be realized in an integrated manner. An essential building block for the realization of this goal is the integration of efficient on-demand single-photon sources within waveguide circuits. Here, we address this challenge by demonstrating the Purcell-enhanced single-photon emission from an In(Ga)As quantum dot coupled to a high-Q cavity-waveguide device. The combination with a piezoelectric actuator further enables the strain-induced emission energy tuning of the quantum dot as well as the cavity mode. We observe wavelength shifts up to 0.85 nm for the quantum dot, with a differential tuning factor of four between emitter and cavity. This allows for the full compensation of the spectral mismatch between a selected quantum dot and the cavity resonance. A nearly twofold enhancement of the spontaneous emission rate is observed at resonance with the on-demand generation of single photons. This demonstration of a strain-tunable emitter in a waveguide-coupled cavity device represents an essential building block for large scale quantum photonic circuits, especially if combined in the future with miniaturization approaches based on recently developed micromachined piezoelectric actuators.
Zero rest-mass fields and the Newman–Penrose constants on flat space
Authors: Gasperín E. , Valiente Kroon J. A.
Published: December 2020

Zero rest-mass fields of spin 1 (the electromagnetic field) and spin 2 propagating on flat space and their corresponding Newman–Penrose (NP) constants are studied near spatial infinity. The aim of this analysis is to clarify the correspondence between data for these fields on a spacelike hypersurface and the value of their corresponding NP constants at future and past null infinity. To do so, Friedrich’s framework of the cylinder at spatial infinity is employed to show that, expanding the initial data in terms spherical harmonics and powers of the geodesic spatial distance ρ to spatial infinity, the NP constants correspond to the data for the second highest possible spherical harmonic at a fixed order in ρ. In addition, it is shown that for generic initial data within the class considered in this article, there is no natural correspondence between the NP constants at future and past null infinity—for both the Maxwell and spin-2 field. However, if the initial data are time-symmetric, then the NP constants at future and past null infinity have the same information.
Effects of mechanical constraint on thermally induced reverse martensitic transformation in granular shape memory ceramic packings
Authors: Rauch Hunter A. , Yu Hang Z.
Published: December 2020

Zirconia-based ceramics exhibit shape memory and superelastic effects based on the reversible martensitic transformation between tetragonal and monoclinic crystal structures. In the form of granular packings, these shape memory ceramics can be scaled up for bulk applications despite their intrinsic brittleness, while displaying drastically different transformation characteristics than the monolithic counterparts. Here, we present a comparative study to understand the thermally induced reverse martensitic transformation in granular packings and the influence of mechanical constraints. This study employs ZrO2–CeO2 shape memory ceramics of the same composition but with different degrees of mechanical constraints. The explored material forms include loose and jammed granular packings, themselves consisting of polycrystalline or single crystal particles, as well as sintered bulk polycrystals. Except for the latter, no endothermic peak is observed in the heat flow measurement of the reverse transformation process. This unusual behavior is shown to stem from the weak inter-particle mechanical constraint and the transformation heterogeneity among individual particles, rather than stress relaxation or particle rearrangement. To compare, conspicuous endothermic peaks only appear in bursting-type transformations under a strong mechanical constraint. For granular packings, the intra-particle mechanical constraint does not affect the presence of any endothermic peaks in thermal reversion but can influence the austenite start temperature.
Visualization of spontaneous electronic polarization in Pb ion of ferroelectric PbTiO3 by synchrotron-radiation x-ray diffraction
Authors: Abe Tomohiro , Kim Sangwook , Moriyoshi Chikako , Kitanaka Yuuki , Noguchi Yuji , Tanaka Hiroshi , Kuroiwa Yoshihiro
Published: December 2020

In this study, we accurately visualized the valence electron density distributions of ferroelectrics PbTiO3 and BaTiO3 by analyzing synchrotron-radiation powder x-ray diffraction (SXRD) data using the Rietveld method and the maximum entropy method. Clear SXRD evidence indicates that the Pb ion in PbTiO3 is polarized in the ferroelectric phase, whereas the Ba ion in BaTiO3 is not polarized and fully ionized as a Ba2+ ion. The large electronic polarization of the Pb ion is attributed to the anisotropic spatial distribution of the lone-pair electrons of the Pb2+ ion, particularly the anisotropic p-like orbital of the lone-pair electrons caused by the formation of Pb–O covalent bonds. In PbTiO3, the contribution of the electronic polarization of the Pb ion to the spontaneous polarization is significant. We experimentally evaluate the contributions of the ionic polarization and the electronic polarization, respectively, from the valence electron density distribution map and demonstrate that the spontaneous polarization can be calculated from the SXRD data as the sum of them. One of the Ti–O covalent bonds is broken at the phase transition in PbTiO3, whereas no change in the atomic coordination is observed in BaTiO3. When focusing on the covalent bonding network, we propose using a layered material for PbTiO3 in the ferroelectric phase. These results agree well with those of first-principles calculations. We expect further comprehensive valence electron density studies can be performed by combining SXRD experiments and first-principles calculations to better understand the emergence of ferroelectricity.
Genomic data show little geographical structure across the naturally fragmented range of the purple-gaped honeyeater
Authors: Joseph Leo , Campbell Catriona D. , Pedler Lynn , Drew Alex
Published: December 2020

Using single nucleotide polymorphisms and mitochondrial DNA sequences we find some evidence of genetic structure within a widespread and naturally fragmented species, the purple-gaped honeyeater (Lichenostomus cratitius), of southern Australian mallee shrublands. The very earliest stages of differentiation either side of the Nullarbor Barrier may already have been arrested by gene flow, some of which may have been anthropogenically induced.
Lymphatic filariasis in the Southeast Asian region; status and control options
Authors: Chandrasena Nilmini T.G.A. , Premaratna Ranjan , Mallawarachchi Chandana H. , Gunaratna Dinesh G.A.M. , de Nilanthi R.
Published: December 2020

The Global Program to Eliminate Lymphatic Filariasis (GPELF) was launched in year 2000 by the World Health Organization (WHO) with the goal set for elimination by 2020. Over half the global disease burden lies in the Southeast Asian region (SEAR). The preventive chemotherapy (PC) programme has been initiated in all the WHO SEAR member states with varying levels of progress. Maldives, Sri Lanka and Thailand have achieved the goal of elimination as a public health problem (EPHP) within the stipulated period with Bangladesh working towards validation in 2021. Both Sri Lanka and Thailand are continuing with post-validation surveillance combined with selective treatment, striving for zero transmission in-parallel with the morbidity management and disability prevention program (MMDP). Timor-Leste appears close to reaching critical transmission thresholds with 100% coverage and triple therapy in the last round of PC. Data on MMDP activities are insufficient to comment on reaching EPHP status. PC coverage and country reports indicate on-going transmission in Nepal, Myanmar, Indonesia and India requiring further rounds of PC. The PELF has made considerable progress in the SEAR towards elimination but there still remain significant transmission and disease burden in the highly populated countries in SEAR.
Linguistic patterns of spelling of isolated words to dictation and text-composing in Catalan across elementary school (Patrones lingüísticos de la ortografía en el dictado de palabras aisladas y en la composición de textos en catalán en la escuela primaria)
Authors: Tolchinsky Liliana
Published: December 2020

Spelling is a language problem-space, not only a school subject. Successful spelling demands going beyond letter to sound mapping and gaining access to a full representation of the orthographic structure of words. We traced bilingual Catalan/Spanish speakers’ spelling performance in Catalan across elementary school in two tasks: isolated words to dictation and text-composing. Our first goal was to tap the effect of grade level and task on the quantity and types of spelling errors children produce. Our second goal was to prove whether a more accurate spelling of orthographically ambiguous words (i.e., words with alternative phonographic spellings but only one that is orthographically correct) would explain spelling performance in text-composing. Results show that inaccurate spelling decreased significantly with grade level and was higher in dictation than in text-composing. However, lexical and, especially, orthographic errors were found in children’s production until the end of elementary school. Better spellers of orthographically ambiguous words committed fewer errors when producing texts. These findings point at an early implicit awareness of spelling difficulty but a protracted command of ruled orthographic knowledge.
Electronic structure and transport properties of coupled CdS/ZnSe quantum dots
Authors: Liebing Simon , Hahn Torsten , Kortus Jens , Das Bidisa , Chakraborty Arup , Dasgupta Indra
Published: December 2020

Electronic structure and transport characteristics of coupled CdS and ZnSe quantum dots are studied using density functional theory and non equilibrium Greens function method respectively. Our investigations show that in these novel coupled dots, the Frontier occupied and unoccupied molecular orbitals are spatially located in two different parts, thereby indicating the possibility of asymmetry in electronic transport. We have calculated electronic transport through the coupled quantum dot by varying the coupling strength between the individual quantum dots in the limits of weak and strong coupling. Calculations reveal asymmetric current vs voltage curves in both the limits indicating the rectifying properties of the coupled quantum dots. Additionally we discuss the possibility to tune the switching behavior of the coupled dots by different gate geometries.
High-performance coaxial piezoelectric energy generator (C-PEG) yarn of Cu/PVDF-TrFE/PDMS/Nylon/Ag
Authors: Kim Jung Hyuk , Kim Bosung , Kim Sang-Woo , Kang Hyun Wook , Park Min-Chul , Park Dong Hee , Ju Byeong Kwon , Choi Won Kook
Published: December 2020

Coaxial type piezoelectric energy generator (C-PEG) nanofiber was fabricated by a self-designed continuous electrospinning deposition system. Piezoelectric PVDF-TrFE nanofiber as an electroactive material was electrospun at a discharge voltage of 9–12 kV onto a simultaneously rotating and transverse moving Cu metal wire at an angular velocity of ω
g = 60–120 RPM. The piezoelectric coefficient d33 of the PVDF-TrFE nanofiber was approximately −20 pm V−1. The generated output voltage (V
G) increased according to the relationship exp(-α
P) (α = 0.41– 0.57) as the pressure (P) increased from 30 to 500 kpa. The V
G values for ten and twenty pieces of C-PEG were V
G = 3.9 V and 9.5 V at P = 100 kpa, respectively, relatively high output voltages compared to previously reported values. The high V
G for the C-PEG stems from the fact that it can generate a fairly high V
G due to the increased number of voltage collection points compared to a conventional two-dimensional (2-dim) capacitor type of piezoelectric film or fiber device. C-PEG yarn was also fabricated via the dip-coating of a PDMS polymer solution, followed by winding with Ag-coated nylon fiber as an outer electrode. The current and power density of ten pieces of C-PEG yarn were correspondingly 22 nA cm−2 and 8.6 μW cm−3 at V
G = 1.97 V, higher than previously reported values of 5.54 and 6 μW cm−3. The C-PEG yarn, which can generate high voltage compared to the conventional film/nanofiber mat type, is expected to be very useful as a wearable energy generator system.
Hybrid structure of PbS QDs and vertically-few-layer MoS2 nanosheets array for broadband photodetector
Authors: Zhang Kun , Feng Shuanglong , Kang Shuai , Wu Yutong , Zhang Miaomiao , Wang Qingshan , Tao Zhiyong , Fan Yaxian , Lu Wenqiang
Published: December 2020

A novel three-dimensional (3D) vertically-few-layer MoS2 (V-MoS2) nanosheets- zero-dimensional PbS quantum dots (QDs) hybrid structure based broadband photodetector was fabricated, and its photoelectric performance was investigated in detail. We synthesized the V-MoS2 nanosheets by chemical vapor deposition, using the TiO2 layer as the induced layer, and proposed a possible growth mechanism. The use of the TiO2 induction layer successfully changed the growth direction of MoS2 from parallel to vertical. The prepared V-MoS2 nanosheets have a large specific surface area, abundantly exposed edges and excellent light absorption capacity. The V-MoS2 nanosheets detector was then fabricated and investigated, which exhibits a high sensitivity for 635 nm light, a fast response time and an excellent photoelectric response. The V-MoS2 nanosheets with a height of approximately 1 μm successfully broke the light absorption limit caused by the atomic thickness. Finally, we fabricated the PbS QDs/V-MoS2 nanosheets hybrid detector and demonstrated their potential for high-performance broadband photodetectors. The response wavelength of the hybrid detector extends from the visible band to the near-infrared band. The responsivity of the hybrid detector reaches 1.46 A W−1 under 1450 nm illumination. The combination of 3D MoS2 nanosheets and QDs further improves the performance of MoS2-based photodetector devices. We believe that the proposed zero-dimensional QDs and 3D vertical nanosheets hybrid structure broadband photodetector provides a promising way for the next-generation optoelectronic devices.
Critical role of the bending stiffness of the monolayer black phosphorus in its mechanical behaviors: molecular dynamics simulation
Authors: Hao Peng , Zhao Demin , Luan Yalin , Liu Jianlin , Wang Qing
Published: December 2020

Black phosphorus (BP) is a novel two-dimensional nanostructure with wide potential applications in such areas as nanoresonators and nanosensors. In this study, we concentrate on the role of the bending stiffness of the BP monolayer in its mechanical performances, including tension, compression, buckling and bending. Firstly, the stress–strain curve and Young’s modulus of the single layer black phosphorus (SLBP) nanoribbon with different chiral structures are obtained in the tension process via the molecular dynamics (MD) simulation. Next, the loading behavior of the SLBP nanoribbon during compression is simulated via MD. It was found that the bending stiffness of the nanoribbon has an essential effect on its postbuckling behaviors, and an empirical formula is proposed which can accurately depict the postbuckling process. Eventually, the bending properties of chiral SLBP nanoribbons are explored via the MD simulation, and the modified expression of the bending stiffness can better predict its large deflection. These findings are beneficial for us to fully understand mechanical responses of BP, which hold implications in engineering new materials and devices at nanoscale.
Photonic crystal enabled manipulation of optical and electric field in germanium avalanche photodetectors
Authors: Song Jinwen , Yuan Shuai , Cui Chengcong , Li Yi , Zeng Cheng , Xia Jinsong
Published: December 2020

We demonstrate the use of a photonic crystal (PhC) structure to improve the performance of a germanium avalanche photodetector (APD) by simultaneously manipulating the distribution of the optical and electric fields. The PhC is fabricated at the top center of the vertical germanium APD. For a 14 μm diameter device, the 1550 nm responsivity increases from 0.2 to 0.6 A W−1 at unity gain, owing to the resonance-enhanced absorption. Moreover, the structure separates the absorption and multiplication regions of the device, resulting in an increase of the avalanche gain and the gain-bandwidth product. Under −10 dBm input optical power, a 3 dB bandwidth of 34 GHz before avalanche and a clear 40 Gbps eye diagram under avalanche demonstrates good high-speed performance of the device.
Diagnostics and comparative analyzes of plasma parameters in micro hollow cathode discharges with an open and covered external surface of cathode in helium using an additional electrode
Authors: Saifutdinov A I , Sysoev S S
Published: December 2020

In this work, diagnostics and comparative analysis of microhollow cathode discharges with an open and covered external surface of the cathode in helium at atmospheric pressure were carried out. It is shown that by covering the external surface of the cathode, it is possible to achieve the effect when the current–voltage characteristics of the discharge grows in a wider range of discharge currents. Obviously, in this case, the negative glow (NG) plasma of the hollow cathode occupies a significant part of the discharge cell, as evidenced by the measurements carried out with the additional electrode. The electron temperature values determined from the I–U characteristic of the additional electrode are 0.3–0.4 eV for a microhollow cathode discharge with a covered external surface, which indicates that the plasma of such discharge is similar to NG plasma of glow discharge. The fast parts of the second derivatives of the I–U characteristic of the additional measuring electrode demonstrate the detection of the spectra of fast electrons produced as a result of Penning ionization reactions. Moreover, by covering the external surface of the cathode, conditions are created under which the entire discharge volume is occupied by a NG plasma, which makes it possible to achieve a better resolution for recording the spectra of fast electrons.
Critical bending and shape memory effect in magnetoactive elastomers
Authors: Kalita V M , Dzhezherya Yu I , Cherepov S V , Skirta Yu B , Bodnaruk A V , Levchenko G G
Published: December 2020

The results of a study of magnetoactive elastomers (MAEs) consisting of an elastomer matrix with embedded ferromagnetic particles are presented. A continuous critical bending induced by the magnetic field, characterized by a critical exponent for the bending magnitude, and the derivative of which has a singularity in the critical region is reported for the first time. The mechanical stability loss and the symmetry reduction of the magnetic state, which are interrelated with each other, take place at the critical point. The magnetization in the high-symmetric state (below the critical point) is directed along the magnetic field and the torque is absent. Above the critical point, the magnetization and the magnetic field are noncollinear and there arises a torque, which is self-consistent with the bending. The magnetic field dependence of the MAE bending was found to have a hysteresis, which is associated with the magneto-rheological effect. The shape memory effect was also obtained for the MAE bending in a cycle consisting of magnetization, cooling (at H ≠ 0), and heating (at H = 0). The influence of the critical glass transition temperature of the matrix, as well as its melting/solidification temperature, on the magnetic shape memory effect was studied.
A new approach to develop, characterise and model actuating textiles
Authors: Kongahage Dharshika , Spinks Geoffrey M , Richards Christopher J , Shepherd David J , Foroughi Javad
Published: December 2020

Smart materials are capable of recognising environmental stimuli, processing the information arising from the stimuli, and responding to it in an appropriate manner. It is well known that smart textiles provide some interesting possibilities in this regard. Consequently, smart textiles based on artificial muscles polymer actuators will provide a breakthrough to many areas including soft robotics, prosthetics, and healthcare for the benefit of humankind. Therefore, it is a worthy attempt to work on artificial muscle designs to aid them in applications. This paper presents the effect of fibre arrangement within a material structure for force and stroke generation. A method of fabrication, characterisation of actuating textiles was presented with experimental results. Most importantly, a modelling was carried out to develop equations to calculate the force and stroke of actuating textiles which has not been reported to date. A reasonable agreement was found between calculated and measured force/stroke curves of both woven and knitted textiles. The woven textile exhibited a force enhancement directly proportional to the number of actuators while retaining the same strain of the single actuator. Nonetheless, the force and strain of knitted textile were highly dependent on the number of wales and courses per unit length. The fabricated knitted textile showed a lesser strain than the single actuator with a force amplification. However, the performance parameters of as fabricated knitted textiles were higher than the fabricated woven textile. Finally a practical applications, process for bulk manufacturing of silicone coated actuators was proposed to enable them in commercialised products and long length production. This study will enable developers to select the fibre architectures and suitable actuators to suit a particular end requirement.
Power–bandwidth–voltage interaction in piezoelectric vibration energy harvesters with constrained load voltage
Authors: Zhao Sheng , Radhakrishna Ujwal , Lang Jeffrey H
Published: December 2020

This paper analyzes the power–bandwidth–voltage interaction in a piezoelectric vibration energy harvester (PVEH) system, specifically accounting for the operating voltage constraint imposed by the interface power electronics (PE). The analysis is sufficiently generic to apply to different linear PVEHs with their interface PE. The power–bandwidth–voltage relation derived here outlines the best possible PVEH system performance when the PVEH-PE interface voltage is constrained, as is often the case in IoT applications. Alternatively, it can serve as a figure of merit with which to benchmark the performance of existing PVEH systems, and identify best design practices.
An all-day lidar for detecting soft targets over 100 km based on superconducting nanowire single-photon detectors
Authors: Zhang Biao , Guan Yan-Qiu , Xia Linghao , Dong Daxing , Chen Qi , Xu Chi , Wu Cheng , Huang Huixin , Zhang Labao , Kang Lin , Chen Jian , Wu Peiheng
Published: December 2020

It is a big challenge for lidar to detect soft targets over long distances in the atmosphere due to the low reflection of soft targets and the strong atmospheric attenuation. In this paper, we propose an all-day lidar system based on the 4 pixel array superconducting nanowire single-photon detectors. This significantly improves the detection efficiency of the aerosol and other targets by utilizing the advantages of high sensitivity, low dark count rate, wide dynamic range and photon number resolution. The system detects both soft targets and hard targets 100 km away in the atmosphere. In experiments, based on the photon-number resolving detection method, the lidar detects and distinguishes soft and hard targets simultaneously 50 km away during the day. Furthermore, the system obtains the wind field information in the atmosphere by monitoring clouds at a distance exceeding 86 km. The detection results indicate that the system is promising for applications as a long distance all-day lidar.
One or two gaps in Mo8Ga41 superconductor? Local Hall-probe magnetometry study
Authors: Marcin M , Pribulová Z , Kačmarčík J , Medvecká Z , Klein T , Yu Verchenko V , Cambel V , Šoltýs J , Samuely P
Published: December 2020

The magnetization properties of the endohedral cluster superconductor Mo8Ga41 are studied by sensitive Hall-probe magnetometry. The temperature dependence of the lower critical magnetic field H

c1 is obtained and compared to theoretical models accounting for single-gap and two-gap superconductivity. Data can be described by both models with minor differences. These results are confronted with our previous measurements which evidence that the system is inherently single-gap s-wave superconductor but minor additional phases are present also in seemingly perfect samples. We discuss how presence of such additional phases with varying size of the penetration depth and H

c1 field is reflected in magnetization measurements which could lead to misinterpretation of the multigap superconductivity in Mo8Ga41.
Evolution of the superconducting properties from binary to ternary APC-Nb3Sn wires
Authors: Ortino M , Pfeiffer S , Baumgartner T , Sumption M , Bernardi J , Xu X , Eisterer M
Published: December 2020

We present a study conducted on binary Tube Type and ternary powder-in-tube Nb3Sn wires manufactured using the artificial pinning centres-internal oxidation method. All the specimens are doped with Zr: oxide nano-particles of this element are responsible for the pinning improvement, both by refining the A-15 grain-size and their own point-pinning contribution. Low-field

J

c

 

magnetometry confirms that the hadron-hadron Future Circular Collider (FCC-hh) specifications are met by one ternary doped-sample. The differences in microstructure were assessed by scanning electron microscopy/transmission electron microscopy to clarify the reasons for the pinning improvement between the two generations. The deviations from the Dew Hughes model are also discussed, underlying some non-linear addition due to competition between the two pinning mechanisms. Finally, we show how the introduction of Ta as a ternary addition influences the A-15 phase by focusing on the radial inhomogeneities, evaluating the

T

c

 

distribution and Sn composition gradients. The latter are used to model the currents, enabling us to evaluate the individual weights of the pinning mechanisms and their absolute contributions at the High Luminosity-Large Hadron Collider and FCC-hh dipoles operational points.
Measurements of the parameter dependencies of the bootstrap current in the W7-X stellarator
Authors: Neuner U. , Rahbarnia K. , Beidler C.D. , Dinklage A. , Turkin Y. , Stange T. , Andreeva T. , Schilling J. , Thomsen H. , Beurskens M. , Bozhenkov S. , Brunner K.J. , Damm H. , Fuchert G. , Geiger J. , Hergenhahn U. , Höfel U. , Knauer J. , Krychowiak M. , Kwak S. , Langenberg A. , Pablant N. , Pasch E. , Pavone A. , Scott E.R. , Svensson J. , Mora H.Trimino , the Wendelstein 7-X team
Published: December 2020

Intrinsic, diffusion-driven toroidal (bootstrap) currents between −7 and 17 kA were measured in the optimised stellarator Wendelstein 7-X (W7-X) for several magnetic configurations at line-integrated plasma densities between 2 × 1019 and 1.6 × 1020 m−2 and heating powers between 0.5 and 6 MW. The sign of the bootstrap current changes with field reversal, and its magnitude decreases with the mirror term and the rotational transform of the magnetic configuration as well as the line-integrated plasma density, and increases with the heating power. Both the absolute values and the dependencies agree with neoclassical calculations within their respective uncertainties, confirming the neoclassical optimisation of W7-X for small bootstrap currents.
Hybridization and introgression of native and foreignSorbustree species in unique environments of protected mountainous areas
Authors: Hebda Anna , Kempf Marta , Wachowiak Witold , Pluciński Bartosz , Kauzal Paweł , Zwijacz-Kozica Tomasz
Published: December 2020

Hybridization and introgression are important processes influencing the genetic diversity and evolution of species. These processes are of particular importance in protected areas, where they can lead to the formation of hybrids between native and foreign species and may ultimately result in the loss of parental species from their natural range. Despite their importance, the contribution of hybridization and introgression to genetic diversity in Sorbus genus remains not fully recognized. We analysed the genetic and morphological variability of several Sorbus species including native (Sorbus aria), foreign (S. intermedia) and potentially hybrid (S. carpatica) individuals from the Polish Carpathian range. Patterns of variation at 13 nuclear microsatellite loci show hybridization between the tested species and confirm the existence of the hybrid form S. carpatica. Biometric analysis on leaves, based of 10 metric features and three parameters, identified several characters for preliminary taxonomic classification; however, none of them could be used as a fully diagnostic marker for faultless annotation of S. intermedia and S. carpatica. The genetic structure analysis indicated complex patterns of population differentiation and its diverse origin. The results allow assessment of genetic variation and identification of parental species participating in hybridization. This knowledge will advance the management of genetic diversity and development of conservation strategies for efficient maintenance of the unique protected ecosystem.
Dyadic leader–follower dynamics change across situations in captive house sparrows
Authors: Tuliozi Beniamino , Camerlenghi Ettore , Griggio Matteo
Published: December 2020

Individuals can behave as either leaders or followers in many taxa of collectively moving animals. Leaders initiate movements and may incur predation risks, while followers are thought to be more risk-averse. As a group encounters different challenges and ecological situations, individuals in the group may change their social role. We investigated leader and follower roles using dyads of captive house sparrow (Passer domesticus) during both exploration of a novel environment and a simulation of predator attack. During the exploration of a novel environment, individuals behaved consistently either as leaders or followers. However, in the simulated attack tests, individuals in the dyads switched their roles, with “followers” leading the escape flights and “leaders” following them. Our study provides evidence of 1) consistent differences between individuals in behavior during social escape and 2) a relationship between social roles across different situations. We suggest that such relationship hinges on individual risk-taking tendencies, which manifest through different social roles across different ecological situations. We further speculate that risk-taking individuals might gain benefits by following risk-averse individuals during an escape flight.
Small Data Theorizing
Authors: Mayer Vicki
Published: December 2020

Small data theorizing encompasses the ways communities of collaborators deliberate over the status of data through a set of three mediational logics that pose alternatives to datafication. Small data theorizing is a way of generalizing a framework for understanding the role of the collaborators in digital archiving and database design processes, which often involve both communication researchers and ordinary institutions, such as universities and museums. This framework for mediational logics extends the critiques of big data theory, and its monolithic claims about autonomous technologies and power in society, by elaborating the ways people actively maintain their connectedness to data in archival design. At the same time, it joins critical communication theory’s central concerns about power with a praxis. This can help all communication researchers in seeing how communities are theorizing practical alternatives to archives that are designed for big data and their ecosystems.
O-Fucose and Fringe-modified NOTCH1 extracellular domain fragments as decoys to release niche-lodged hematopoietic progenitor cells
Authors: Yu Shuiliang , Wang Weihuan , Albakri Marwah , Yu Xiaoxing , Majihail Gurnoor , Lim Seunghwan , Lopilato Rachel K , Ito Atsuko , Letterio John , Haltiwanger Robert S , Zhou Lan
Published: December 2020

Successful hematopoietic progenitor cell (HPC) transplant therapy is improved by mobilizing HPCs from the bone marrow niche in donors. Notch receptor–ligand interactions are known to retain HPCs in the bone marrow, and neutralizing antibodies against Notch ligands, Jagged-1 or Delta-like ligand (DLL4), or NOTCH2 receptor potentiates HPC mobilization. Notch–ligand interactions are dependent on posttranslational modification of Notch receptors with O-fucose and are modulated by Fringe-mediated extension of O-fucose moieties. We previously reported that O-fucosylglycans on Notch are required for Notch receptor–ligand engagement controlling hematopoietic stem cell quiescence and retention in the marrow niche. Here, we generated recombinant fragments of NOTCH1 or NOTCH2 extracellular domain carrying the core ligand-binding regions (EGF11–13) either as unmodified forms or as O-fucosylglycan-modified forms. We found that the addition of O-fucose monosaccharide or the Fringe-extended forms of O-fucose to EGF11–13 showed substantial increases in binding to DLL4. Furthermore, the O-fucose and Fringe-extended NOTCH1 EGF11–13 protein displayed much stronger binding to DLL4 than the NOTCH2 counterpart. When assessed in an in vitro 3D osteoblastic niche model, we showed that the Fringe-extended NOTCH1 EGF11–13 fragment effectively released lodged HPC cells with a higher potency than the NOTCH2 blocking antibody. We concluded that O-fucose and Fringe-modified NOTCH1 EGF11–13 protein can be utilized as effective decoys for stem cell niche localized ligands to potentiate HPC egress and improve HPC collection for hematopoietic cell therapy.