bluuebunny/crossref_metadata_2025 huggingface dataset:
New algorithm using L1 regularization for measuring electron energy spectra
Authors: Sakaki Hironao , Yamashita Tomohiro , Akagi Takashi , Nishiuchi Mamiko , Dover Nicholas P. , Lowe Hazel F. , Kondo Kotaro , Kon Akira , Kando Masaki , Tachibana Yasuhiko , Obata Takayuki , Shiokawa Keiichiro , Miyatake Tatsuhiko , Watanabe Yukinobu
Published: July 2020

Retrieving the spectrum of physical radiation from experimental measurements typically involves using a mathematical algorithm to deconvolve the instrument response function from the measured signal. However, in the field of signal processing known as “Source Separation” (SS), which refers to the process of computationally retrieving the separate source components that generate an overlapping signal on the detector, the deconvolution process can become an ill-posed problem and crosstalk complicates the separation of the individual sources. To overcome this problem, we have designed a magnetic spectrometer for inline electron energy spectrum diagnosis and developed an analysis algorithm using techniques applicable to the problem of SS. An unknown polychromatic electron spectrum is calculated by sparse coding using a Gaussian basis function and an L1 regularization algorithm with a sparsity constraint. This technique is verified by using a specially designed magnetic field electron spectrometer. We use Monte Carlo simulations of the detector response to Maxwellian input energy distributions with electron temperatures of 5.0 MeV, 10.0 MeV, and 15.0 MeV to show that the calculated sparse spectrum can reproduce the input spectrum with an optimum energy bin width automatically selected by the L1 regularization. The spectra are reproduced with a high accuracy of less than 4.0% error, without an initial value. The technique is then applied to experimental measurements of intense laser accelerated electron beams from solid targets. Our analysis concept of spectral retrieval and automatic optimization of energy bin width by sparse coding could form the basis of a novel diagnostic method for spectroscopy.
Junction using collinear nickel oxide insulator produces spin-polarized current
Authors: Liebendorfer Adam
Published: July 2020

Prototype breaks spin sublattice symmetry and induces nonequivalent transport for spin-up and spin-down currents in a step forward for combining spintronics with semiconductors.
Asymptotic shear and the intrinsic conformal geometry of null-infinity
Authors: Herfray Yannick
Published: July 2020

In this article, we propose a new geometrization of the radiative phase space of asymptotically flat space-times: we show that the geometry induced on null-infinity by the presence of gravitational waves can be understood to be a generalization of the tractor calculus of conformal manifolds adapted to the case of degenerate conformal metrics. It follows that the whole formalism is, by construction, manifestly conformally invariant. We first show that a choice of asymptotic shear amounts to a choice of linear differential operator of order 2 on the bundle of scales of null-infinity. We refer to these operators as Poincaré operators. We then show that Poincaré operators are in one-to-one correspondence with a particular class of tractor connections, which we call “null-normal” (they generalize the normal tractor connection of conformal geometry). The tractor curvature encodes the presence of gravitational waves, and the non-uniqueness of flat null-normal tractor connections corresponds to the “degeneracy of gravity vacua” that has been extensively discussed in the literature. This work thus brings back the investigation of the radiative phase space of gravity to the study of (Cartan) connections and associated bundles. This should allow us, in particular, to proliferate invariants of the phase space.
Ion optics simulation of an ion beam setup coupled to an electrospray ionization source, strengths, and limitations
Authors: Chiarinelli J. , Bolognesi P. , Avaldi L.
Published: July 2020

A unified approach to achieve a start-to-end ion optics simulation of an ion beam apparatus coupled to an electrospray ionization source is presented. We demonstrate that simulations enable reliable information on the behavior and operation of the apparatus to be obtained, but due to the collisions with the buffer gas in the initial stages of the setup, the results concerning the kinetic energy of the ion beam must be treated with care.
Partial directed coherence based graph convolutional neural networks for driving fatigue detection
Authors: Zhang Weiwei , Wang Fei , Wu Shichao , Xu Zongfeng , Ping Jingyu , Jiang Yang
Published: July 2020

The mental state of a driver can be accurately and reliably evaluated by detecting the driver’s electroencephalogram (EEG) signals. However, traditional machine learning and deep learning methods focus on the single electrode feature analysis and ignore the functional connection of the brain. In addition, the recent brain function connection network method needs to manually extract substantial brain network features, which results in cumbersome operation. For this reason, this paper introduces graph convolution combined with brain function connection theory into the study of mental fatigue and proposes a method for driving fatigue detection based on the partial directed coherence graph convolutional neural network (PDC-GCNN), which can analyze the characteristics of single electrodes while automatically extracting the topological features of the brain network. We designed a fatigue driving simulation experiment and collected the EEG signals. In the present work, the PDC method constructs the adjacency matrix to describe the relationship between EEG channels, and the GCNN combines single-electrode local brain area information and brain area connection information to further improve the performance of detecting fatigue states. Based on the features of differential entropy (DE) and power spectral density (PSD), the average recognition accuracy of ten-fold cross validation is 84.32% and 83.84%, respectively. For further experiments on each subject, the average recognition results are 95.24%/5.10% (PSD) and 96.01%/3.81% (DE). This research can be embedded in the vehicle driving fatigue detection system, which has practical application value.
Revisiting heat treatment and surface activation of GaAs photocathodes: In situ studies using scanning tunneling microscopy and photoelectron spectroscopy
Authors: Biswas Jyoti , Cen Jiajie , Gaowei Mengjia , Rahman Omer , Liu Wei , Tong Xiao , Wang Erdong
Published: July 2020

The lifetime of GaAs photocathodes in polarized electron guns is limited due to the delicate activation layer. An atomically clean and smooth GaAs surface is needed to deposit a robust activation layer, such as Cs2Te, with longer lifetime compared to traditional (Cs,O) activation. A previous experiment with Cs2Te activation on GaAs used heat cleaning temperatures around 400°C to avoid an increase in surface roughness [Bae et al., Appl. Phys. Lett. 112, 154101 (2018)]. High-temperature heat cleaning around 580°C, which results in a relatively contamination-free surface, could be one possible way to improve quantum efficiency. However, one should be cautious about surface roughness degradation during high-temperature heat cleaning. In this paper, we report results of surface roughness measurements on native, heat cleaned, and (Cs,O) activated GaAs photocathodes under vacuum. The results, measured by ultrahigh vacuum scanning tunneling microscopy, show that the surface roughness improves as the heat cleaning temperature is increased, by at least a factor of three for 580°C heat cleaning, compared to the native sample. Activation with (Cs,O) is shown to increase surface roughness by a factor of four compared to a 580°C heat cleaned sample. This confirms that high-temperature heat cleaning can be useful for depositing good quality robust activation layers on GaAs. We also report chemical analysis for each step of preparation for p-doped GaAs photocathodes using X-ray photoelectron spectroscopy (XPS), angle-resolved XPS, and ultraviolet photoelectron spectroscopy. Our results indicate that the (Cs,O) activation layer forms a sandwich structure consists of Cs and oxygen. We found no formation of any specific compound such as Cs2O or Cs11O3.
The physics of active polymers and filaments
Authors: Winkler Roland G. , Gompper Gerhard
Published: July 2020

Active matter agents consume internal energy or extract energy from the environment for locomotion and force generation. Already, rather generic models, such as ensembles of active Brownian particles, exhibit phenomena, which are absent at equilibrium, particularly motility-induced phase separation and collective motion. Further intriguing nonequilibrium effects emerge in assemblies of bound active agents as in linear polymers or filaments. The interplay of activity and conformational degrees of freedom gives rise to novel structural and dynamical features of individual polymers, as well as in interacting ensembles. Such out-of-equilibrium polymers are an integral part of living matter, ranging from biological cells with filaments propelled by motor proteins in the cytoskeleton and RNA/DNA in the transcription process to long swarming bacteria and worms such as Proteus mirabilis and Caenorhabditis elegans, respectively. Even artificial active polymers have been synthesized. The emergent properties of active polymers or filaments depend on the coupling of the active process to their conformational degrees of freedom, aspects that are addressed in this article. The theoretical models for tangentially and isotropically self-propelled or active-bath-driven polymers are presented, both in the presence and absence of hydrodynamic interactions. The consequences for their conformational and dynamical properties are examined, with emphasis on the strong influence of the coupling between activity and hydrodynamic interactions. Particular features of emerging phenomena in semi-dilute systems, induced by steric and hydrodynamic interactions, are highlighted. Various important, yet theoretically unexplored, aspects are featured, and future challenges are discussed.
Improvement of the performances of a commercial hand-held laser-induced breakdown spectroscopy instrument for steel analysis using multiple artificial neural networks
Authors: Poggialini F. , Campanella B. , Legnaioli S. , Pagnotta S. , Raneri S. , Palleschi V.
Published: July 2020

In this article, we present a study on the optimization of the analytical performance of a commercial hand-held laser-induced breakdown spectroscopy instrument for steel analysis. We show how the performances of the instrument can be substantially improved using a non-linear calibration approach based on a set of Artificial Neural Networks (ANNs), one optimized for the determination of the major elements of the alloy, and the others specialized for the analysis of minor components. Tests of the instrument on steel samples used for instrument internal calibration demonstrate a comparable accuracy with the results of the ANNs, while the latter are considerably more accurate when unknown samples, not used for calibration/training, are tested.
A singularity-free torsion angle potential for coarse-grained molecular dynamics simulations
Authors: Tan Cheng , Jung Jaewoon , Kobayashi Chigusa , Sugita Yuji
Published: July 2020

Conventional torsion angle potentials used in molecular dynamics (MD) have a singularity problem when three bonded particles are collinearly aligned. This problem is often encountered in coarse-grained (CG) simulations. Here, we propose a new form of the torsion angle potential, which introduces an angle-dependent modulating function. By carefully tuning the parameters for this modulating function, our method can eliminate the problematic angle-dependent singularity while being combined with existing models. As an example, we optimized the modulating function of the torsion angle potential for popular CG models of biomolecules based on the statistics over experimental structures deposited in the Protein Data Bank. By applying our method to designed and natural biomolecules, we show that the new torsion angle potential is able to eliminate the singularity problem while maintaining the structural features in the original models. Furthermore, by comparing our design with previous methods, we found that our new potential has advantages in computational efficiency and numerical stability. We strongly recommend the usage of our new potential in the CG simulations of flexible molecules.
Automated parameterization of quantum-mechanically derived force-fields including explicit sigma holes: A pathway to energetic and structural features of halogen bonds in gas and condensed phase
Authors: Campetella Marco , De Mitri Nicola , Prampolini Giacomo
Published: July 2020

In classical molecular dynamics, general purpose atomistic force-fields (FFs) often deliver inaccurate results when dealing with halogen bonds (XBs), notwithstanding their crucial role in many fields of science, ranging from material design to drug development. Given the large dimensions of the systems of interest, it would be therefore desirable to increase the FF accuracy maintaining the simplicity of the standard Lennard-Jones (LJ) plus point charge description to avoid an excessive computational cost. A simple yet effective strategy consists in introducing a number of virtual sites able to mimic the so-called “explicit σ-hole.” In this work, we present an automated FF parameterization strategy based on a global optimization of both LJ and charge parameters with respect to accurate quantum mechanical data, purposely computed for the system under investigation. As a test case, we report on two homologue series, characterized either by weak or strong XBs, namely, the di-halogenated methanes and the mono-, di-, and tri-substituted acetonitriles, taking into consideration Cl, Br, and I substituents. The resulting quantum mechanically derived FFs are validated for each compound in the gas and in the condensed phase by comparing them to general purpose and specific FFs without virtual sites and to highly accurate reference quantum mechanical data. The results strongly support the adoption of the specific FFs with virtual sites, which overcome the other investigated models in representing both gas phase energetics and the structural patterns of the liquid phase structure related to the presence of XBs.
First formed dislocations in microcompressed c-oriented GaN micropillars and their subsequent interactions
Authors: Magagnosc Daniel J. , Derenge Michael A. , Jones Kenneth A.
Published: July 2020

c-oriented GaN micropillars created from single crystals containing ∼103 or ∼106 dislocations/cm2 and a thick heteroepitaxially grown film containing ∼109 were compressed to study methods to accommodate strain during heteroepitaxial growth. The yield stress in the 103 samples was found to be the highest, and it was the lowest in the 109 samples. The 103 and 106 pillars often failed catastrophically but the 109 pillars almost never did. This was linked to the high stresses required to generate sufficient pyramidal dislocations to accommodate plastic strain and dislocation interactions, which precipitated axial fracture. Transmission electron microscopy analysis shows categorically that the first formed dislocations are ⅓⟨1123_⟩{1122} dislocations, and that a few ⅓⟨1123_⟩{0111} dislocations found were formed by a cross slip in the vicinity of where the former dislocations interacted. When compared with the similar stress patterns created in the heteroepitaxial growth of AlGaN films on GaN substrates, the analysis suggests that there is no pathway for creating basal plane dislocations during growth from the pyramidal dislocations, which require high applied stresses; the basal plane dislocations would provide relief for the mismatch strain while not penetrating the region where active devices are fabricated in the film. Rather, it will be necessary to find a method for creating shear stress in the basal plane during growth to form them directly.
Vortex dynamics and acoustic sources in the wake of finned cylinders during resonance excitation
Authors: Islam Md Rashidul , Shaaban Mahmoud , Mohany Atef
Published: July 2020

The flow–sound interaction mechanism and its effect on the vortex dynamics in the wake of circular finned cylinders are experimentally investigated using phase-locked particle image velocimetry at Reynolds numbers between 7 × 104 and 9.5 × 104. In addition, a hybrid experimental–numerical technique using the theory of vortex sound is employed to quantify the acoustic sources and sinks in the vicinity of finned cylinders with different fin-to-root diameter ratios, Df/Dr = 1.5, 2.0, and 2.5. The results show that changing the diameter ratio of the fins induces fundamental changes in the wake structure and the vortex shedding process downstream of the cylinder. Finned cylinders induce stronger vortex cores with a shorter formation length compared to their equivalent bare cylinders. Moreover, the flow topology over the spanwise direction shows that acoustic resonance results in uniform cylindrical vortex cores with less three-dimensional distortion, which demonstrates that the flow field becomes highly two-dimensional during resonance excitation. Quantification of the energy transfer between the flow and the sound fields reveals an enhancement in the acoustic energy production closer to the cylinder with a significant dependence on its fin-to-root diameter ratio.
Free-space self-interference microresonator with tunable coupling regimes
Authors: Li Mingfang , Wang Yifan , Jiang Xiaoshun , Bo Fang , Ruan Yong , Tan Yidong
Published: July 2020

The device of free-space self-interference microresonator coupled by fiber tapers is proposed. Different from sensors with similar structures on-chip and benefit to the combination between microcavity and optical fiber sensing, the coupling regime is adjustable and a separated sensing area from coupling regions is available. This method makes it feasible to optimize coupling efficiency in detection and broaden the scope of application in dissipative sensing. The transmission spectrum exhibits a distinct phenomenon under a long optical path of sensing arm, including quasi-sinusoidal modulation and profile split. Based on that, transmission characteristics are analyzed by theoretical stimulations and the subsequent experiments are in good agreement with the theory. In addition, we estimate the sensing performance of this device and that the sensitivity can reach −4.76 dB/(10−7 RIU) with a 1 m sensing arm theoretically when applied in monitoring the refractive index change, which is almost an order of magnitude larger than the previously reported data. Besides being adjustable, compact, and efficient, this device shows great potential in the precision measurement and expands the applicable measurement field of similar structures, such as pull pressure that cannot be detected using bus straight waveguides.
Kinetics of the luminescence decay of Fe2+ impurity centres in polycrystalline ZnSe upon excitation by an electron beam
Authors: Il’ichev N.N. , Gladilin A.A. , Gulyamova E.S. , Kalinushkin V.P. , Mironov S.A. , Sidorin A.V. , Pashinin P.P. , Tumorin V.V. , Gavrishchuk E.M. , Savin D.V. , Rodin S.A. , Ikonnikov V.B. , Chukichev M.V.
Published: July 2020

The kinetics of the decay of the luminescence of Fe2+ ions is measured at nitrogen temperature in polycrystalline ZnSe excited by a short pulse of accelerated electrons. The time dependence of the luminescence intensity differs from the exponential one, observed upon excitation of luminescence by a short light pulse. The obtained nonexponential dependence is theoretically described. The explanation is based on the quenching effect of the excited state of the Fe2+ ion by free electrons of the volume charge of the current of accelerated electrons in the sample (Auger effect). It was shown that the relaxation of the volume charge after the electron-accelerating voltage is removed makes a significant contribution to the decay kinetics of the impurity luminescence.
Peculiarities of the formation of photonic nanojets by a matrix of dielectric microtoroids
Authors: Geints Yu.E. , Panina E.K. , Zemlyanov A.A.
Published: July 2020

We report the results of theoretical modelling of photonic nanojets (PNJs) formed by laser radiation scattering on a single-layer ordered assembly of dielectric microtoroids placed on the surface of a transparent matrix (silicone film). Using the method of computational electrodynamics (FDTD), the main PNJ parameters (length, width, peak intensity) are analysed under the conditions of mutual influence of the light fields of neighbouring microparticles. It is shown that the main factor affecting the PNJ characteristics under study is the spatial configuration of the radiation-scattering particle, namely, the internal diameter of its cross section. It is found that for certain configurations of toroid placement in a cluster, a PNJ ensemble is implemented with parameters significantly better than those for a single toroid.
Heat transfer in water under laser heating through fibres for endovenous laser coagulation
Authors: Minaev V.P. , Minaev N.V. , Bogachev V.Yu. , Kaperiz K.A. , Fedorov D.A. , Yusupov V.I.
Published: July 2020

We report the results of studying heat transfer in water heated by a cw laser with wavelengths of 1.55 and 1.94 μm through optical fibres with end-face and radial outputs. It is shown that, depending on the power and wavelength of the radiation, heat transfer is implemented via convection, bubble boiling, or explosive boiling and occurs asymmetrically, mainly in the forward − upward direction for the fibre with the end-face output and upward for the radial output.
Low-threshold, single-transverse-mode, 940-nm vertical-cavity surface-emitting laser with a mode filter and half-wavelength cavity
Authors: Ren Q.H. , Wang J. , Yang M. , Wang H.J. , Cheng Z. , Huang Y.Q. , Ren X.M. , Ji H.M. , Luo S.
Published: July 2020

We demonstrate a structure for a vertical-cavity surface-emitting laser (VCSEL) with a mode filter and half-wavelength (λ/2) cavity. The effects of λ/2- and λ-cavities on the threshold current are studied. The thickness and etched diameter of the mode filter are optimised to achieve single-transverse-mode output. The results show that when changing from λ-cavity to λ/2-cavity, the threshold current of the VCSEL decreases by 30.7% (from 0.85 mA to 0.65 mA). In addition, for the mode-filter thickness of 80 nm, and the etched diameter of 2.5 μm, the side mode suppression ratio reaches 90 dB, which meets the requirement of single-transverse-mode output. The VCSELs with the optimised design can overcome many difficulties and have great potential in 3D face recognition.
Effect of optical field ionisation on the generation of wake fields by femtosecond laser pulses in an inhomogeneous plasma
Authors: Umarov I.R. , Andreev N.E.
Published: July 2020

We consider the interaction of a high-intensity short laser pulse with an argon gas during optical field ionisation. Modelling in a three-dimensional cylindrical symmetric geometry is performed at various moderately relativistic intensities and positions of the focal plane of the laser beam in the case of both optical gas ionisation and a pre-ionised plasma. The influence of the processes occurring during optical field ionisation of the gas on the generation of wake waves is investigated, and the conditions are found under which intense wake fields are produced in a plasma formed from an inhomogeneous argon gas jet. The possibility of using a gas with a large number of electrons on the outer shell (argon) to excite intense wake waves and accelerate electrons is demonstrated. Despite significant ionisation refraction of the laser pulse on a radially inhomogeneous density profile of plasma electrons formed during optical field ionisation, the region of the parameters of the laser pulse and the gas target is determined at which ionisation refraction leads to the excitation of an intense wake wave. It is found that in a pre-ionised plasma a wake wave is not generated even at the same laser radiation intensity.
Quantum cascade laser with bound-to-quasi-continuum optical transitions at a temperature of up to 371 K
Authors: Molodtsov I.S. , Raspopov N.A. , Lobintsov A.V. , Danilov A.I. , Krysa A.B. , Zasavitskii I.I.
Published: July 2020

Based on a matched Ga0.47In0.53As/Al0.48In0.52As heteropair, we have developed a quantum cascade laser emitting at a wavelength of 7.4 μm. The chosen heterostructure with a relatively large number of quantum wells and barriers represents two mini-bands separated by a mini-gap with a localised doublet level near the upper mini-band, which provides a wide emission band (∼100 cm−1). In a pulse regime, the maximal laser operation temperature is 371 K. Such a high temperature is explained by two factors: a large energy of the transfer from the doublet to the upper mini-band and a large volt defect. The characteristic temperatures T
0 are found, which are equal to 170 K for low (less than 300 K) temperatures and 270 K for the range of 300 − 370 K. In addition, optical cavity losses are determined to be 2.5 and 7.7 cm−1 at temperatures of 80 and 254 K, respectively. The pulse power is 0.3 W at 80 K and 0.05 W at 293 K.
10-W 4.6-μm quantum cascade lasers
Authors: Dudelev V.V. , Mikhailov D.A. , Babichev A.V. , Losev S.N. , Kognovitskaya E.A. , Lyutetskii A.V. , Slipchenko S.O. , Pikhtin N.A. , Gladyshev A.G. , Denisov D.V. , Novikov I.I. , Karachinsky L.Ya. , Kuchinskii V.I. , Egorov A.Yu. , Sokolovskii G.S.
Published: July 2020

Ridge quantum-cascade lasers emitting near 4.6 μm are fabricated and their power and spectral characteristics are studied. Stable pulsed lasing with an output optical power exceeding 10 W (more than 5 W from one facet) at room temperature is demonstrated.
Smart adaptive optical system for correcting the laser wavefront distorted by atmospheric turbulence
Authors: Rukosuev A.L. , Belousov V.N. , Nikitin A.N. , Sheldakova Yu.V. , Kudryashov A.V. , Bogachev V.A. , Volkov M.V. , Garanin S.G. , Starikov F.A.
Published: July 2020

An adaptive optical system is developed to correct the wavefront of laser radiation distorted by a turbulent air flow. The use of a field-programmable gate array as the main control element makes it possible to achieve a system bandwidth of 2 kHz. The results of experiments on dynamic correction of the phase of a laser beam distorted by a flow of heated air are presented and analysed.
Mono- and sesquiterpenes as a starting platform for the development of antiviral drugs
Authors: Yarovaya Olga I. , Salakhutdinov Nariman F.
Published: July 2020

The revies focuses on low-molecular-weight plant metabolites (mono- and sesquiterpenes) exhibiting antiviral activity. Data on antiviral action of both essential oils and plant extracts and their components are provided. Structures of biologically active natural mono- and sesquiterpenoids as well as their derivatives showing a pronounced antiviral activity are presented. A special attention is given to the description of targets for antiviral therapy. The mechanisms of action of antiviral agents are considered.

The bibliography includes 163 references.
Targeting nanoparticles to the brain by exploiting the blood–brain barrier impermeability to selectively label the brain endothelium
Authors: Gonzalez-Carter Daniel , Liu Xueying , Tockary Theofilus A. , Dirisala Anjaneyulu , Toh Kazuko , Anraku Yasutaka , Kataoka Kazunori
Published: July 2020

Significance

Therapy-loaded nanoparticles may be directed to the brain by functionalization with ligands targeting blood–brain barrier (BBB)-associated proteins. However, such targeting strategies have inherent brain-specificity limitations, as the target proteins are also significantly expressed in peripheral organs. Here, we present a counterintuitive targeting strategy that exploits the high impermeability of the BBB to selectively retain ligand labels on the surface of brain endothelium. Nanoparticles capable of binding the displayed ligands are consequently directed specifically to the brain microvasculature. This two-step targeting strategy paves the way to overcome the peripheral “off-target” nanoparticle accumulation, increasing the clinical translation of nanoparticle-based therapies. In addition, it shifts the identification of brain-target proteins from focusing on differential expression to instead focus on differential endocytic rates.
Experimental and theoretical evidence for hydrogen doping in polymer solution-processed indium gallium oxide
Authors: Huang Wei , Chien Po-Hsiu , McMillen Kyle , Patel Sawankumar , Tedesco Joshua , Zeng Li , Mukherjee Subhrangsu , Wang Binghao , Chen Yao , Wang Gang , Wang Yang , Gao Yanshan , Bedzyk Michael J. , DeLongchamp Dean M. , Hu Yan-Yan , Medvedeva Julia E. , Marks Tobin J. , Facchetti Antonio
Published: July 2020

Significance

Solution processing of high-performance, high-Ga-content IGZO thin-film transistors (TFTs)—or compositionally simpler and, hence, technologically more desirable indium gallium oxide (IGO) TFTs—remains challenging and an impediment to manufacturing low-temperature, solution-processed metal oxide electronics. Here, the performance of aqueous solution-processed IGO TFTs is greatly enhanced with polyvinyl alcohol in the precursor solution, yielding a >70-fold increase in electron mobility. By achieving optimal H doping and conversion from six- to four-coordinate Ga, PVA addition suppresses deep trap defect localization. This result not only offers a route to high-performance, ultra-stable metal oxide semiconductor electronics with simple binary compositions, but also provides powerful tools to probe H locations in amorphous metal oxides via a combination of experimental and theoretical approaches.
Populism in performance?
Authors: Montgomery Martin
Published: July 2020

Much commentary on the discourse of Donald Trump’s populist appeal has tended to focus on his use of Twitter, to the relative neglect of his campaign rallies. Yet his campaign rallies during the presidential election were arguably crucial for delivering the votes which secured his victory. Members of his own team, and Trump himself, certainly thought so.

Since the election Trump has continued to campaign in rallies in key states with increasing vigour, attracting
large audiences as the second term elections in 2020 approach.

These large-scale public events confirm the bond between Trump and his base. But they also require us to re-focus attention beyond Trump as an individual figure to the process of mutual engagement between him and his highly active and vocal
audience.

This article, by examining the overall communicative behaviour of participants at his rallies asks: “Is the
audience Trump’s creation or is Trump the audience’s creation?”
German discourse particles in the second language classroom
Authors: Trotzke Andreas , Bidese Ermenegildo , Moroni Manuela Caterina
Published: July 2020

One of the main pedagogical objectives for language learners at high proficiency levels is to use ‘cohesive
devices’ when writing a text or conducting a conversation. Usually, curricula stress the importance of clause-internal cohesion
(by means such as connectives: and, but, when, because, etc.).
By contrast, we stress the importance of cohesion at the level of the dialogue and in this context focus on discourse (aka
‘modal’) particles as a means to yield cohesion at that level. In this domain, German discourse particles represent a challenging
learning objective for second language learners of German. This paper explores some production patterns of German discourse
particles in L2 German by L1 Italian learners. We show that looking at those elements can provide new insights because these
elements allow us to tease apart problems within syntax as compared to the lexicon-pragmatics interface in second language
learning.
Electro-Optically Switchable Optical True Delay Lines of Meter-Scale Lengths Fabricated on Lithium Niobate on Insulator Using Photolithography Assisted Chemo-Mechanical Etching
Authors: Zhou Jun-xia , Gao Ren-hong , Lin Jintian , Wang Min , Chu Wei , Li Wen-bo , Yin Di-feng , Deng Li , Fang Zhi-wei , Zhang Jian-hao , Wu Rong-bo , Cheng Ya
Published: July 2020

Optical true delay lines (OTDLs) of low propagation losses, small footprints and high tuning speeds and efficiencies are of critical importance for various photonic applications. Here, we report fabrication of electro-optically switchable OTDLs on lithium niobate on insulator using photolithography assisted chemo-mechanical etching. Our device consists of several low-loss optical waveguides of different lengths which are consecutively connected by electro-optical switches to generate different amounts of time delay. The fabricated OTLDs show an ultra-low propagation loss of ∼ 0.03 dB/cm for waveguide lengths well above 100 cm.
Zirconium Aided Epitaxial Growth of InxSey on InP(111) Substrates
Authors: Zheng Cheng , Zhao Dapeng , Cai Xinqiang , Huang Wantong , Meng Fanqi , Zhang Qinghua , Tang Lin , Hu Xiaopeng , Gu Lin , Ji Shuai-Hua , Chen Xi
Published: July 2020

Layered material indium selenide (In
x
Se
y
) is a promising candidate for building next-generation electronic and photonic devices. We report a zirconium aided MBE growth of this van der Waals material. When co-depositing zirconium and selenium onto an indium phosphide substrate with a substrate temperature of 400°C at a constant zirconium flux rate of 0.01 ML/min, the polymorphic In
x
Se
y
layer emerges on top of the insulating ZrSe2 layer. Different archetypes, such as InSe, α-In2Se3 and β-In2Se3, are found in the In
x
Se
y
layers. A negative magnetoresistance of 40% at 2K under 9T magnetic field is observed. Such an In
x
Se
y
/ZrSe2 heterostructure with good lattice-matching may serve as a candidate for device applications.
An Origin of Dzyaloshinskii–Moriya Interaction at Graphene-Ferromagnet Interfaces Due to the Intralayer RKKY/BR Interaction
Authors: Yang Jin , Li Jian , Lin Liangzhong , Zhu Jia-Ji
Published: July 2020

We present a theory of both the itinerant carrier-mediated RKKY interaction and the virtual excitations-mediated Bloembergen–Rowland (BR) interaction between magnetic moments in graphene induced by proximity effect with a ferromagnetic film. It is shown that the RKKY/BR interaction consists of the Heisenberg, Ising, and Dzyaloshinskii–Moriya (DM) terms. In the case of the nearest distance, we estimate the DM term from the RKKY/BR interaction is about 0.13 meV for the graphene/Co interface, which is consistent with the experimental result of DM interaction 0.16±0.05 meV. Our calculations indicate that the intralayer RKKY/BR interaction may be a possible physical origin of the DM interaction in the graphene-ferromagnet interface. This work provides a new perspective to comprehend the DM interaction in graphene/ferromagnet systems.
Unexpectedly Strong Diamagnetism of Self-Assembled Aromatic Peptides
Authors: Yang Haijun , Wang Zixin , Mu Liuhua , Song Yongshun , Hu Jun , Zhang Feng , Fang Haiping
Published: July 2020

There is a considerable amount of work that shows the biomagnetism of organic components without ferromagnetic components at the molecular level, but it is of great challenge to cover the giant gap of biomagnetism between their experimental and theoretical results. Here we show that the diamagnetism of aromatic peptides is greatly enhanced for about 11 times by self-assembling, reaching two orders of magnitude higher than the mass susceptibility of pure water. The self-assembly of aromatic rings in the peptide molecules plays the key role in such a strong diamagnetism.
Dimensional analysis in relativity and in differential geometry
Authors: Mana P G L Porta
Published: July 2020

This note provides a short guide to dimensional analysis in Lorentzian and general relativity and in differential geometry. It tries to revive Dorgelo and Schouten’s notion of ‘intrinsic’ or ‘absolute’ dimension of a tensorial quantity. The intrinsic dimension is independent of the dimensions of the coordinates and expresses the physical and operational meaning of a tensor. The dimensional analysis of several important tensors and tensor operations is summarized. In particular it is shown that the components of a tensor need not have all the same dimension, and that the Riemann (once contravariant and thrice covariant) and Ricci (fully covariant) curvature tensors are dimensionless. The relation between dimension and operational meaning for the metric and stress–energy–momentum tensors is discussed; and the main conventions for the dimensions of these two tensors and of Einstein's constant are reviewed. A more thorough and updated analysis is available as a preprint.
Improvement of Bi doping in ZnO nanocrystals by co-doping with Al: crystal geometry calculations and photocatalytic activity
Authors: Emara Mahmoud M , Hassan Abdelhamied A , El-Dissouky Ali , Patten P Gregory Van
Published: July 2020

In this work we demonstrate enhancement in visible-light photocatalytic activity (PCA) of ZnO nanoparticles (NPs) with minimal attenuation of visible light transmittance. This approach can benefit numerous optoelectronic and photocatalytic applications. ZnO NPs were p-n co-doped with Al and Bi to improve Bi doping into the ZnO crystal. Al- and/or Bi-doped ZnO was coprecipitated by ammonia from aqueous nitrate solutions of Zn2+, Al3+, and Bi3+, followed by microwave heating. Doping concentrations in Al- and Bi- doped ZnO (AZO and BZO) and Al/Bi co-doped ZnO (ABZO) were 1, 3, 5, and 7 mole %. The resulting NPs were characterized by XRD, TEM, EDS, BET, and UV-visible absorption. While EDS shows that almost all added Bi was incorporated into the ZnO, XRD analysis of BZO reveals formation of α-Bi2O3 as a secondary phase due to the poor Bi solubility in ZnO. Co-doping of Al with Bi suppressed α-Bi2O3 formation and increased Bi solubility in ZnO. XRD-based calculations of the lattice constants and deformation strain, stress, and energy all show insertion of Al and/or Bi into the crystal with different extents according to the dopants’ solubilities into ZnO. AZO and BZO NPs had E
g lowered by 0.05–1.39 eV and 0.30–0.70 eV, respectively, relative to ZnO. On the other hand, ABZO had E
g reductions of only 0.01–0.20 eV due to formation of acceptor-donor complex through co-doping. ABZO gave higher PCA enhancements with respect to E
g reductions (Δk
photo/–ΔE
g) than either AZO and BZO, with values up to 370, 126, and 13 min–1 eV–1, respectively.
Characterization of an operational quantum resource in a critical many-body system
Authors: Sarkar S , Mukhopadhyay C , Bayat A
Published: July 2020

Quantum many-body systems have been extensively studied from the perspective of quantum technology, and conversely, critical phenomena in such systems have been characterized by operationally relevant resources like entanglement. In this paper, we investigate robustness of magic (RoM), the resource in magic state injection based quantum computation schemes, in the context of the transverse field anisotropic XY model. We show that the the factorizable ground state in the symmetry broken configuration is composed of an enormous number of highly magical H states. We find the existence of a point very near the quantum critical point where magic contained explicitly in the correlation between two distant qubits attains a sharp maxima. Unlike bipartite entanglement, this persists over very long distances, capturing the presence of long range correlation near the phase transition. We derive scaling laws and extract corresponding exponents around criticality. Finally, we study the effect of temperature on two-qubit RoM and show that it reveals a crossover between dominance of quantum and thermal fluctuations.
Slowing of acoustic waves in electrorheological and string-fluid complex plasmas
Authors: Schwabe M , Khrapak S A , Zhdanov S K , Pustylnik M Y , Räth C , Fink M , Kretschmer M , Lipaev A M , Molotkov V I , Schmitz A S , Thoma M H , Usachev A D , Zobnin A V , Padalka G I , Fortov V E , Petrov O F , Thomas H M
Published: July 2020

The PK-4 laboratory consists of a direct current plasma tube into which microparticles are injected, forming a complex plasma. The microparticles acquire many electrons from the ambient plasma and are thus highly charged and interact with each other. If ion streams are present, wakes form downstream of the microparticles, which lead to an attractive term in the potential between the microparticles, triggering the appearance of microparticle strings and modifying the complex plasma into an electrorheological form. Here we report on a set of experiments on compressional waves in such a string fluid in the PK-4 laboratory during a parabolic flight and on board the International Space Station. We find a slowing of acoustic waves and hypothesize that the additional attractive interaction term leads to slower wave speeds than in complex plasmas with purely repulsive potentials. We test this hypothesis with simulations, and compare with theory.
3D Interactive Multimedia in English Language Learning
Authors: Sudarmilah Endah , Maharani Utami Yunia , Yuliana Irma
Published: July 2020

Language has an important role in communicating. English is the most widely international language used in the world. Based on the results of observations made at Elementary School that the media used during the learning process are worksheets and textbooks, and it has not used learning media yet. This research aims to determine the feasibility of the media and the effect of using interactive learning media toward learning outcomes in English material. The method of this research used “Research and Development” with a development model ADDIE (Analysis-Design-Development-Implementation-Evaluation). This research uses design Matching pretest posttest control group. The media validation is categorized as feasible with an average value of 79.37%. And the material content validation in the category is very feasible with an average value of 96.97%. The measurement of student learning outcomes is done by providing tests in the form of multiple choices. Based on the average value of learning outcomes control class are smaller than the experimental class that is 67.43 < 82.30. The statistical analysis used in this research is normality test, homogeneity test, hypothesis test, and n-gain test. Assessment of students are categorized as acceptable with an average value of 85%. The results of the data analysis were strengthened using the independent sample t test, with the value obtained sig = 0,451 < α = 0.05 then H0 is rejected and H1 is accepted. The n-gain test results obtained a value of 66.90 for the experimental class and the control class of 32.53. The result of this research is the use of learning media in which it has a greater influence than conventional methods and there are significant differences in the student learning outcomes.
Module for Developing Learning Media Applications for Wireless Networks in Project-Based Microtic Hotspot Materials for Microtic Setup (Configuration) Competency Improvement
Authors: Indriyanti A D , Prehanto D R , Wibawa S C , Prihanto A , Sujatmiko B , Samastabuana D E , Wibawa RP
Published: July 2020

Implement project-based learning to improve student competency in managing hotspot configurations on MikroTik in accordance with Y generation characteristics. With the other aim of knowing the feasibility of M-netsys application through assessment instruments from Walker & Hess for media and RISTKDIKTI for materials with scale measurements using assessment scales. The research method used in this research is Research and Development (R & D) using One-Shot Case Study testing strategy with minimum learning completeness ≥ 3.0 or B. This research was conducted in 2015 Wireless Network class with 25 students. The results of the research have been obtained: (1) To improve student competence in setting (configuration) hotspot on MikroTik which according to Y generation characteristics can be done by implementing project-based learning in the learning process through the application of M-netsys learning media supplement. (2) The feasibility of M-netsys learning material with the research instrument from RISTEKDIKTI is stated very strong with the percentage of 84.4%. Meanwhile, the prevalence of M-netsys media through the assessment instrument of Walker & Hess is considered very strong with a percentage of 83.58%. (3) Students’ learning outcomes after using M-netsys as many as 25 students completed and expressed classically with 100% percentage.
Contribution Model Thinking Electronic Digital Creative and Knowledge of Competence of Electrical Engineering Student Surabaya State University
Authors: Kholis N , Munoto
Published: July 2020

This study uses a quantitative research approach with case study method. The quantitative approach is inductive research methods, scientific, and objective where the data was obtained in the form of figures or statements that are assessed and analyzed by a statistical analysis. The purpose of this study to obtain an explanation of the theory and the laws of reality. Quantitative research was developed using mathematical models, theories or hypotheses.

The correlation obtained correlation coefficient of 0.857 which indicates that there is a high positive correlation between the value of the creativity of the students (X) and the value of the final study outcome data (Y). Besides the correlation coefficient of 0.857 also means that increasing the value of creativity of students (X) then the value of the final learning outcomes (Y) will also increase. Furthermore, based on the results of testing the hypothesis on the correlation coefficient can be concluded that with a confidence level of 95% is sufficient evidence to suggest that there is a close relationship statistically significant between the creativity of the students (X) and the value of the final learning outcomes (Y).
Critical study of stem-based learning in order to develop century skills 21
Authors: Muslim S. , Fathoni A. , Kusumawati N. , Rahmadyanti E.
Published: July 2020

The term STEM was introduced by the United States National Science Foundation (1990) as an abbreviation of “Science, Technology, Engineering, & Mathematics”. In the Indonesian context, STEM refers to four fields of science, namely science, technology, engineering, and mathematics. STEM learning is an approach to learning where Science, Technology, Engineering, and Mathematics are learning processes that focus on solving problems in everyday life. Does STEM learning can print students who have 21st century skills in order to solve various problems in everyday life. In order to answer these questions, it is necessary to do research with the title: A critical study of STEM-based learning in order to build 21st century skills. In connection with that, the purpose of this study is to find out how much STEM learning is able to improve student learning outcomes so that they have 21st century skills in order to solve various problems in daily life. This research was conducted through the study of literature as an activity of gathering information that is relevant to the topic that was used as the object of research. Data collection techniques are carried out by conducting a study of a number of reference books and relevant research results. Data analysis techniques are done through descriptive-qualitative techniques with sentences that are easily understood in an effort to get answers to the problems under study, so that an overview of the contribution of STEM learning to student learning outcomes is obtained in order to solve various problems in daily life. The study found that: (1) STEM-based learning is one of the right lessons to prepare skilled human resources to live in the 21st century; (2) STEM-based learning can be integrated with cooperative learning models, Project Based Learning (PBJ), Problem Based Learning (PBL) and other learning models; (3) STEM-based learning can be applied to all levels of education (elementary, secondary and high); and (4) STEM-based learning is useful in the context of developing student careers.