bluuebunny/crossref_metadata_2025 huggingface dataset:
Inhomogeneous interface dipole effect at the Schottky junctions of PdCrO2 on β-Ga2O3 (2¯01) substrates
Authors: Miyakawa T. , Harada T. , Ito S. , Tsukazaki A.
Published: July 2020

We report the lateral and vertical electrical conduction properties of PdCrO2 thin films grown on insulating Al2O3 (001) and conducting β-Ga2O3(2¯01) substrates. The c-axis oriented PdCrO2 films on the both substrates showed metallic temperature dependence of in-plane resistivity down to 2 K. In PdCrO2/β-Ga2O3 vertical devices, rectifying current density–voltage (J–V) characteristics revealed the formation of a Schottky barrier at the PdCrO2/β-Ga2O3 interface. The Schottky barrier height (SBH) of 1.2–1.8 eV, evaluated by J–V characteristics, is significantly larger than 0.8 eV expected from the usual Mott–Schottky relation based on the electron affinity of β-Ga2O3 (4.0 eV) and the work function of PdCrO2 (4.8 eV) determined by ultraviolet photoelectron spectroscopy. The enhanced SBH at the PdCrO2/β-Ga2O3 interface indicates the existence of interface dipoles, as in the case of PdCoO2/β-Ga2O3. Besides, we observed a large difference of the SBH between the J–V measurements (1.2–1.8 eV) and capacitance measurements (2.0–2.1 eV). While the SBH is definitely enhanced by the interface dipole effect, the level of enhancement at the PdCrO2/β-Ga2O3 interface is rather inhomogeneous, different from that at the PdCoO2/β-Ga2O3. In fact, two typical types of interfaces were found by a high-angle annular dark-field scanning transmission electron microscope, which would be the origin of the inhomogeneous SBH. Further understanding of the interface formation between delafossite oxides and β-Ga2O3(2¯01) will improve the performance of Ga2O3 Schottky junctions as a power diode available at high temperatures.
Fabrication and evaluation via nuclear quadrupole resonance of a palm cubic-anvil pressure cell
Authors: Nakagawa Satoshi , Gochi Jun , Kuwayama Takanori , Nagasaki Shoko , Takahashi Teruo , Cheng Jinguang , Uwatoko Yoshiya , Fujiwara Naoki
Published: July 2020

A “palm” cubic-anvil pressure cell (PCAC) having an outer diameter of 60 mm, the smallest cubic-anvil cell to date, was fabricated to insert in a large-bore superconducting magnet. The pressure cell has a sample space of ϕ 2.5 × 1.5 mm2, which is fairly large for a pressure cell that can reach a high pressure above 4 GPa. Pressure homogeneity was monitored from the 63Cu nuclear-quadrupole-resonance linewidth of Cu2O up to 6.7 GPa. The linewidth first increased with increasing pressure up to 4 GPa and then saturated above 4 GPa. The pressure homogeneity was better than that of a piston-cylinder pressure cell. The PCAC is advantageous because a large sample space and high pressure homogeneity are secured even at high pressures.
High-field electromagnetic radiation converts carbon nanotubes to nanoribbons embedded with carbon nanocrystals
Authors: Chen Pingping , Wang Xinya , Luan Y. , Fei Zhe , Lacroix Brice , Lei Shuting , R. Das Suprem
Published: July 2020

One-dimensional carbon nanomaterials such as carbon nanotubes (CNTs) and graphene nanoribbons (GNRs) are promising for future applications in nanoelectronics and nanophotonics due to their unique characteristics such as topological edge states, chirality, and quantum confinement. Despite the chemical unzipping method of producing GNRs from CNTs, using energetic photons to control light–matter interaction and shape materials at the nanoscale has great promise, especially for chemical-free and on-demand manufacturing. Here, we exploit the high electromagnetic field from a Ti:Sapphire femtosecond laser to interact with CNTs, causing ultrafast energy transfer between the photons and the nanotubes and converting them to GNRs and carbon nanocrystals. Probed with scattering-type scanning near-field optical microscopy, the nanoribbons are identified as semiconducting and/or insulating, a strikingly different electronic phase compared with the original metallic CNTs. Our method of employing high-field and nonequilibrium processes with an ultrafast laser to alter the shape and transform the electronic properties is scalable, does not necessitate high-temperature processes, and is highly spatially controllable—conditions that pave the way for manufacturing nanoscale hybrid materials and devices.
Enhanced all-optical switching and domain wall velocity in annealed synthetic-ferrimagnetic multilayers
Authors: Wang Luding , van Hees Youri L. W. , Lavrijsen Reinoud , Zhao Weisheng , Koopmans Bert
Published: July 2020

All-optical switching (AOS) of the magnetization in synthetic ferrimagnetic Pt/Co/Gd stacks has received considerable interest due to its high potential toward integration with spintronic devices, such as magnetic tunnel junctions (MTJs), to enable ultrafast memory applications. Post-annealing is an essential process in the MTJ fabrication to obtain an optimized tunnel magnetoresistance ratio. However, upon integrating AOS with an MTJ in prospect, the annealing effects on single-pulse AOS and domain wall (DW) dynamics in the Pt/Co/Gd stacks have not been systematically investigated yet. In this study, we experimentally explore the annealing effect on AOS and field-induced DW motion in Pt/Co/Gd stacks. The results show that the threshold fluence (F0) of AOS is reduced significantly as a function of annealing temperature (Ta) ranging from 100 °C to 300 °C. Specifically, a 28% reduction of F0 can be observed upon annealing at 300 °C, which is a critical Ta for MTJ fabrication. Finally, we also demonstrate a significant increase in the DW velocity in the creep regime upon annealing, which is attributed to annealing-induced Co/Gd interface intermixing. Our findings show that the annealed Pt/Co/Gd system facilitates ultrafast and energy-efficient AOS, as well as enhanced DW velocity, which is highly suitable toward opto-spintronic memory applications.
Quantum dense metrology by an SU(2)-in-SU(1,1) nested interferometer
Authors: Du Wei , Chen J. F. , Ou Z. Y. , Zhang Weiping
Published: July 2020

With the help of quantum entanglement, quantum dense metrology (QDM) is a technique that can make joint estimates of two conjugate quantities such as phase and amplitude modulations of an optical field, with an accuracy beating the standard quantum limit simultaneously. SU(1,1) interferometers (SUIs) can realize QDM with detection loss tolerance but is limited in absolute sensitivity. Here, we present a QDM scheme with a linear or SU(2) interferometer nested inside an SUI. By using a degenerate SUI and controlling the phase angle of the phase-sensitive amplifiers in the SUI, we can achieve the optimum quantum enhancement in the measurement precision of an arbitrary mixture of phase and amplitude modulation.
Magnetization around mix jets entering inertial confinement fusion fuel
Authors: Sadler James D. , Li Hui , Haines Brian M.
Published: July 2020

Engineering features are known to cause jets of ablator materials to enter the fuel hot-spot in inertial confinement fusion implosions. The Biermann battery mechanism wraps them in a self-generated magnetic field. We show that higher-Z jets have an additional thermoelectric magnetic source term that is not present for hydrogen jets, verified here through a kinetic simulation. It has similar magnitude to the Biermann term. We then include this in an extended magneto-hydrodynamic approach to post process an xRAGE radiation-hydrodynamic implosion simulation. The simulation includes an accurate model for the capsule fill tube, producing a dense carbon jet that becomes wrapped in a 4000 T magnetic field. A simple spherical carbon mix model shows that this insulates the electron heat conduction enough to cause contraction of the jet to an optically thick equilibrium. The denser magnetized jet hydrodynamics could change its core penetration and therefore the final mix mass, which is known to be well correlated with fusion yield degradation. Fully exploring this will require self-consistent magneto-hydrodynamic simulations. Experimental signatures of this self-magnetization may emerge in the high energy neutron spectrum.
Generation of multipeak spectrum of spin torque oscillator in non-linear regime
Authors: Iwakiri Shuichi , Sugimoto Satoshi , Niimi Yasuhiro , Kobayashi Kensuke , Kozuka Yusuke , Takahashi Yukiko K. , Kasai Shinya
Published: July 2020

We investigate the spectral characteristics of a spin torque oscillator (STO) excited by the spin Hall-induced spin current. We observe that the modest spin current injection triggers the conventional single peak oscillating behavior of the STO. As the spin current is further increased to enter the non-linear regime, we find the transition of the spectrum from a single peak to a multipeak structure whose frequency spacing is constant. This behavior can be primarily explained by the extremely broadened peak of the STO, which is accompanied by the frequency-dependent filtering by the transmission line. To explain the observation more quantitatively, we also discuss that the multipeak may reflect the characteristics of the intrinsic dynamics of the STO in the non-linear regime.
Three-dimensional mesoporous nanocube TiO2/reduced graphene oxide composites with enhanced lithium storage properties
Authors: Yue Zongkai , Zhen Xu , Ai Jia , Shi Qirang , Mao Tianyu , Zhen Mengmeng , Wang Zhiyong , Peng Shitao
Published: July 2020

Titanium dioxide (TiO2) and TiO2-based composite materials have been widely investigated in lithium-ion batteries (LIBs) owing to their small volume change and high safety during the cycling process. However, the low ionic and electrical conductivity of TiO2 nanomaterials leads to poor cycling performances for LIBs. Herein, we successfully synthesized three-dimensional (3D) mesoporous nanocube TiO2/reduced graphene oxide (TiO2/RGO) composites with a simple hydrothermal method without using any surfactants and high-temperature calcination. The as-prepared TiO2/RGO composites are characterized by x-ray diffraction, scanning electron microscopy, electron microscopy, and Brunauer–Emmett–Teller surface area. Benefiting from the RGO conductive substrates and 3D nanotube mesoporous structure, the as-prepared TiO2/RGO composites exhibit high specific capacities of ∼180 mA h g−1 at 1.2 C after 300 cycles as anode materials for lithium-ion batteries (LIBs).
Distinguishing resonance symmetries with energy-resolved photoion angular distributions from ion-pair formation in O2 following two-photon absorption of a 9.3 eV femtosecond pulse
Authors: Larsen Kirk A. , Lucchese Robert R. , Slaughter Daniel S. , Weber Thorsten
Published: July 2020

We present a combined experimental and theoretical study on the photodissociation dynamics of ion-pair formation in O2 following resonant two-photon absorption of a 9.3 eV femtosecond pulse, where the resulting O+ ions are detected using 3D momentum imaging. Ion-pair formation states of Σg−3 and 3Πg symmetry are accessed through predissociation of optically dark continuum Rydberg states converging to the B Σg−2 ionic state, which are resonantly populated via a mixture of both parallel–parallel and parallel–perpendicular two-photon transitions. This mixture is evident in the angular distribution of the dissociation relative to the light polarization and varies with the kinetic energy release (KER) of the fragmenting ion pair. The KER-dependent photoion angular distribution reveals the underlying two-photon absorption dynamics involved in the ion-pair production mechanism and indicates the existence of two nearly degenerate continuum resonances possessing different symmetries, which can decay by coupling to ion-pair states of the same total symmetry through internal conversion.
Determining complex spin mixing conductance and spin diffusion length from spin pumping experiments in magnetic insulator/heavy metal bilayers
Authors: Roy Kuntal
Published: July 2020

Magnetic insulators are promising materials for the development of energy-efficient spintronics. Unlike metallic counterparts, the magnetic insulators are characterized by the imaginary part of the interfacial spin mixing conductance as well in a bilayer with heavy metals, and it is responsible for the field-like toque in spin–orbit torque devices. Here, we study the underlying theoretical constructs and develop a general strategy to determine the complex spin mixing conductance from the experimental results of ferromagnetic resonance and spin pumping. The results show that the imaginary part of the spin mixing conductance can be one order more than the real part and it matches the critical trend of spin mixing conductance with thickness of the heavy metal. The interpretation of experimental results also indicates that at small thicknesses, the interface contribution becomes significant and a bulk diffusion model cannot explain the results. A thickness-dependent spin diffusion length is necessary too that is tantamount to the Elliott–Yafet spin relaxation mechanism in the heavy metals. Also, we effectively explain the experimental results while inserting a copper layer with varying thicknesses in between the magnetic insulator and the heavy metal using spin-circuit formalism.
Temozolomide-Loaded Solid Lipid Nanoparticles@Hydrogel for Local Treatment of Tumour
Authors: Ji Weiwei , Liu Zhilan
Published: July 2020

Temozolomide (TMZ) is a significant anticancer agent especially for chemotherapy of glioblastoma. In order to reduce the recurrence rate of cancer, in this work an injectable hydrogel composed of TMZ-loaded solid lipid nanoparticles (SLNs) was designed for filling the cavity of a glioblastoma operation. First, TMZ-loaded SLNs (T-SLNs) were prepared by emulsion solvent diffusion and evaporation technology. The optimised formulation showed a particle size of 190.8±15.3nm, a Zeta potential of −20.2±1.7mV, an entrapment efficiency (EE%) of 99.3±0.5%, and drug loading (DL%) of 15.1±2.7%. The optimised formulation was freeze-dried and characterised by scanning electron microscopy (SEM), differential thermogravimetry (DTG), X-ray diffraction (XRD), and stability tests. The freeze-dried T-SLNs were then incorporated into a hydroxypropyl chitosan (HPCS)/diarylaldehyde PEG (PEG-DF) hydrogel bonded with an MRI contrast agent. The hydrogels were evaluated for invitro drug release and cytotoxicity. The results indicated that compared with free TMZ, the T-SLNs@hydrogel prolonged drug release, and both blank SLNs and hydrogel materials did not exhibit cytotoxicity, suggesting the therapeutic efficacy of TMZ was reserved. Thus, comparing with its conventional oral administration, the obtained TMZ-loaded SLNs and the hydrogel could be more potent for local treatment of glioblastoma after an operation.
Adjuvanted H5N1 influenza vaccine enhances both cross-reactive memory B cell and strain-specific naive B cell responses in humans
Authors: Ellebedy Ali H. , Nachbagauer Raffael , Jackson Katherine J. L. , Dai Ya-Nan , Han Julianna , Alsoussi Wafaa B. , Davis Carl W. , Stadlbauer Daniel , Rouphael Nadine , Chromikova Veronika , McCausland Megan , Chang Cathy Y. , Cortese Mario , Bower Mary , Chennareddy Chakravarthy , Schmitz Aaron J. , Zarnitsyna Veronika I. , Lai Lilin , Rajabhathor Arvind , Kazemian Cheyann , Antia Rustom , Mulligan Mark J. , Ward Andrew B. , Fremont Daved H. , Boyd Scott D. , Pulendran Bali , Krammer Florian , Ahmed Rafi
Published: July 2020

Significance

The development of a universal influenza vaccine is a major public health need globally, and identifying the optimal formulation will be an important first step for developing such a vaccine. Here we show that a two-dose immunization of humans with an inactivated, AS03-adjuvanted H5N1 avian influenza virus vaccine engaged both the preexisting memory and naive B cell compartments. Importantly, we show that the recruited memory B cells after first immunization were directed against conserved epitopes within the H5 HA stem region while the responses after the second immunization were mostly directed against strain-specific epitopes within the HA globular head. Taken together these findings have broad implications toward optimizing vaccination strategies for developing more effective vaccines against pandemic viruses.
The biochemical basis for the cooperative action of microRNAs
Authors: Briskin Daniel , Wang Peter Y. , Bartel David P.
Published: July 2020

Significance

MicroRNAs (miRNAs) are short RNAs that guide the repression of most human messenger RNAs (mRNAs) and play many important roles in physiology and development. To function, each miRNA associates with an Argonaute (AGO) protein to form a complex in which the miRNA pairs to sites in mRNAs, thereby targeting these mRNAs for repression, and AGO associates with TNRC6, a protein that recruits the mRNA-repression machinery. For previously unknown reasons, repression is often more effective when miRNAs pair to sites close to one another. We find that in the presence of the TNRC6 AGO-binding domain, which can simultaneously bind multiple AGO proteins, miRNA-AGO complexes bind a two-site target RNA with high cooperatively, providing a biochemical explanation for cooperative action in cells.
Ranking essential bacterial processes by speed of mutant death
Authors: Gallagher Larry A. , Bailey Jeannie , Manoil Colin
Published: July 2020

Significance

Essential genes control the most fundamental processes of bacterial life but are missing from standard comprehensive mutant screens because loss-of-function mutants are absent from the libraries examined. We employed a method for generating insertion mutations at genome-saturation scale in naturally competent bacteria. The insertions can be immediately detected by sequencing, making it possible to follow their loss from the population during subsequent growth. The procedure allowed us to order essential processes based on how rapidly inactivation blocks DNA replication and growth. Processes whose inactivation most immediately blocks replication represent attractive antibiotic targets, since even partial inhibition should curtail growth.
Active strike-slip faults and an outer frontal thrust in the Himalayan foreland basin
Authors: Duvall Michael J. , Waldron John W. F. , Godin Laurent , Najman Yani
Published: July 2020

Significance

The Himalayan mountain belt results from continuing convergence between the Indian Plate and Asia. Damaging earthquakes occur on major thrust faults north of the Main Frontal Thrust (MFT). To the south, the Ganga foreland basin is typically described as undeformed. We show that active thrust and strike-slip faults, with accumulated slip up to ∼100 m, pass under the trace of the MFT into the foreland basin in eastern Nepal, leading to propagation of deformation at least ∼37 km into the foreland basin beneath the densely populated Ganga plain. The development of these faults at the active thrust front helps to explain structures preserved in higher thrust sheets of the Himalaya, and in ancient mountain belts elsewhere.
Integration of ancient DNA with transdisciplinary dataset finds strong support for Inca resettlement in the south Peruvian coast
Authors: Bongers Jacob L. , Nakatsuka Nathan , O’Shea Colleen , Harper Thomas K. , Tantaleán Henry , Stanish Charles , Fehren-Schmitz Lars
Published: July 2020

Significance

Genomic, archaeological, historical, and biogeochemical data are integrated to examine six individuals from two cemeteries in the Chincha Valley of southern Peru. Results demonstrate consistency among these independent datasets in support of a model of north Peruvian coast peoples moving to the Chincha Valley during the Late Horizon (1400 to 1532 CE). Our transdisciplinary work provides strong support for Inca resettlement, a state policy that reshaped the Andean sociopolitical landscape yet represents one of the most notoriously difficult phenomena to identify in the archaeological record. This research offers an ideal case study that sets a methodological standard for investigating ancient mobility in complex societies by synthesizing aDNA with multiple independent lines of evidence.
Quantifying the contribution of Fc-mediated effector functions to the antiviral activity of anti–HIV-1 IgG1 antibodies in vivo
Authors: Wang Pengfei , Gajjar Mili R. , Yu Jian , Padte Neal N. , Gettie Agegnehu , Blanchard James L. , Russell-Lodrigue Kasi , Liao Laura E. , Perelson Alan S. , Huang Yaoxing , Ho David D.
Published: July 2020

Significance

Virus-neutralizing monoclonal antibodies have been tested for the treatment or prevention of HIV-1 infection. Such an antibody can block virus infectivity and mediate killing of virus-infected cells by Fc-mediated effector functions. The relative contributions of these two antibody activities in vivo have not been quantified previously. By quantitatively analyzing results from experiments conducted in HIV-1–infected humanized mice and SHIV-infected rhesus macaques, we have determined that Fc-mediated effector functions contribute about 25–45% to the total antiviral activity of the anti–HIV-1 monoclonal antibodies tested.
Using lengthwise scaling to compare feature frequencies across text lengths on Reddit
Authors: Liimatta Aatu
Published: July 2020

Texts of different lengths can be difficult to compare using quantitative methods. This is particularly true if many of the texts are extremely short, as is commonly the case with social media comments, where the median text length may be only a few dozen words. In this paper, I explore lengthwise scaling, that is, scaling applied to each text length separately, as a possible approach for getting around some of the statistical problems caused by different text lengths and short texts. I describe two implementations of this family of methods, lengthwise rarity scaling and lengthwise quantile scaling. I show in an exploratory analysis that these scaling methods support earlier results in terms of register differences between Reddit subreddits.
Double trouble
Authors: Eberl Martin
Published: July 2020

Linguistic data from social media is often discussed in the light of constraints, be it due to character limits or the putatively short attention span of users. In November 2017, Twitter eased one such constraint, increasing the maximum length of tweets from 140 to 280 characters. The present longitudinal study shows that this change has had an effect on the linguistic surface structure of tweets, especially in regard to optional syntactical and metatextual features. I discuss the origin and nature of these changes and their relation to hard constraints of social media platforms in addition to highlighting the impact on methodological aspects of future longitudinal studies of Twitter data which may cover periods both before and after the switch.
Constructing corpora from images and text
Authors: Christiansen Alex , Dance William , Wild Alexander
Published: July 2020

Visual analysis represents a significant oversight in the corpus literature, and possibly one that may lead to unintended omissions, particularly when analysing social media. In this chapter we introduce Visual Constituent Analysis (VCA), a method of multimodal corpus construction that allows researchers to construct and analyse visual aspects of online media in large-scale corpora. The chapter addresses the shortcomings of a purely textual approach to discourse analysis when dealing with social media texts and offers a solution using computer ‘Vision’-based image annotation (in our case Google Cloud Vision). Finally, we demonstrate how our approach can be used to analyse a sample of 150,000 micro-blog posts from Twitter and show the difference in level of user interaction with combined image/texts over language-only social media texts.
Transmembrane TNF drives osteoproliferative joint inflammation reminiscent of human spondyloarthritis
Authors: Kaaij Merlijn H. , van Tok Melissa N. , Blijdorp Iris C. , Ambarus Carmen A. , Stock Michael , Pots Désiree , Knaup Véronique L. , Armaka Marietta , Christodoulou-Vafeiadou Eleni , van Melsen Tessa K. , Masdar Huriatul , Eskes Harry J.P.P. , Yeremenko Nataliya G. , Kollias George , Schett Georg , Tas Sander W. , van Duivenvoorde Leonie M. , Baeten Dominique L.P.
Published: July 2020

TNF plays a key role in immune-mediated inflammatory diseases including rheumatoid arthritis (RA) and spondyloarthritis (SpA). It remains incompletely understood how TNF can lead to different disease phenotypes such as destructive peripheral polysynovitis in RA versus axial and peripheral osteoproliferative inflammation in SpA. We observed a marked increase of transmembrane (tm) versus soluble (s) TNF in SpA versus RA together with a decrease in the enzymatic activity of ADAM17. In contrast with the destructive polysynovitis observed in classical TNF overexpression models, mice overexpressing tmTNF developed axial and peripheral joint disease with synovitis, enthesitis, and osteitis. Histological and radiological assessment evidenced marked endochondral new bone formation leading to joint ankylosis over time. SpA-like inflammation, but not osteoproliferation, was dependent on TNF-receptor I and mediated by stromal tmTNF overexpression. Collectively, these data indicate that TNF can drive distinct inflammatory pathologies. We propose that tmTNF is responsible for the key pathological features of SpA.
Pressure Effects on the Transport and Structural Properties of Metallic Glass-Forming Liquid
Authors: Cao Qi-Long , Huang Duo-Hui , Yang Jun-Sheng , Wang Fan-Hou
Published: July 2020

Transport and structural properties of metallic glass-forming liquid Cu50Zr50 are investigated by molecular dynamics simulation, under high pressures from 1 bar to 70 GPa. The following results have been obtained: (i) reversals of component diffusion coefficients (D
Cu and D
Zr) are observed at the reversion pressure. At low pressures below the reversion pressure, D
Cu/D
Zr decreases from about 1.4 to 1.0. At high pressures above the reversion pressure, D
Cu/D
Zr decreases more rapidly from 1.0 to about 0.7. (ii) Component diffusion coefficients decay exponentially with pressure up to reversion pressure, then the strength of the exponential dependence changes, while the pressure-dependent behavior of viscosity can be well described by a single exponential relation over the full range of pressure. (iii) The Stokes–Einstein relation (SER) works well at low pressures and starts to be violated at the breakdown pressure. For glass-forming liquid Cu50Zr50 along the 2000 K isotherm, the breakdown pressure equals the reversion pressure of component diffusion coefficients and is about 35 GPa. (iv) The pressure dependences of the ratio between component diffusion coefficients can be used to predict the breakdown pressure of SER along isotherm. The validity of SER and the reversals of component diffusion coefficients are found to be related to the pressure dependence of the relative total fractions of predominant Voronoi polyhedrons around individual components.
Synthesis of Highly Stable One-Dimensional Black Phosphorus/h-BN Heterostructures: A Novel Flexible Electronic Platform
Authors: Song Jingyan , Duan Shuai , Chen Xin , Li Xiangjun , Yang Bingchao , Liu Xiaobing
Published: July 2020

Layered black phosphorus (BP) has recently emerged as a promising semiconductor because of its tunable band gap, high carrier mobility and strongly in-plane anisotropic properties. One-dimensional (1D) BP materials are attractive for applications in electronic and thermal devices, owing to their tailored charge and phonon transports along certain orientations. However, the fabrication of 1D BP materials still remains elusive thus far. We herein report the successful synthesis and characterization of nanotube-like BP for the first time by a selective composite with hexagonal boron nitride (h-BN) nanotubes under high pressure and high temperature conditions. The produced 1D BP/h-BN composites possess flexible diameter, length and thickness by adjusting the experimental synthesis parameters. Interestingly, it is important to notice that the stability of our BP sample has been significantly improved under the formation of heterostructures, which can actively promote their commercial applications. Our experimental work, together with first-principles calculations, presents a new scalable strategy of designing 1D tube-like BP/h-BN heterostructures that are promising candidates for flexible and high efficiency electronic platform.
Quantum Droplets in a Mixture of Bose–Fermi Superfluids
Authors: Wang Jing-Bo , Pan Jian-Song , Cui Xiaoling , Yi Wei
Published: July 2020

We study the formation of quantum droplets in the mixture of a single-component Bose–Einstein condensate (BEC), and a two-species Fermi superfluid across a wide Feshbach resonance. With repulsive boson-boson and attractive boson-fermion interactions, we show that quantum droplets can be stabilized by attractive fermion-fermion interactions on the Bardeen–Cooper–Schrieffer (BCS) side of the resonance, and can also exist in the deep BEC regime under weak boson-fermion interactions. We map out the phase diagram for stable droplets with respect to the boson-boson and boson-fermion interactions, and discuss the role of different types of quantum fluctuations in the relevant regions of the BCS-BEC crossover. Our work reveals the impact of fermion pairing on the formation of quantum droplets in Bose–Fermi mixtures, and provides a useful guide for future experiments.
Band Alignment at the Al2O3/β-Ga2O3 Interface with CHF3 Treatment*
Authors: Liu Hao , Liu Wen-Jun , Xiao Yi-Fan , Liu Chao-Chao , Wu Xiao-Han , Ding Shi-Jin
Published: July 2020

The energy band alignment at the atomic layer deposited Al2O3/β-Ga2O3 interface with CHF3 treatment was characterized by x-ray photoelectron spectroscopy and secondary ion mass spectrometry (SIMS). With additional CHF3 plasma treatment, the conduction band offset increases from 1.95±0.1 eV to 2.32±0.1 eV; and the valence band offset decreases from 0.21±0.1 eV to −0.16±0.1 eV. As a result, the energy band alignment changes from type I to type II. This energy band alignment transition could be attributed to the downshift of the core-level of Ga 3d, resulting from the Ga–F bond formation in the F-rich interfacial layer, which is confirmed by the SIMS results.
Unusual Anomalous Hall Effect in a Co2MnSi/MnGa/Pt Trilayer
Authors: Li Shan , Lu Jun , Wen Lian-Jun , Pan Dong , Wang Hai-Long , Wei Da-Hai , Zhao Jian-Hua
Published: July 2020

An ultra-thin Co2MnSi(0.5 nm)/MnGa(1.5 nm) bilayer capped with Pt (5 nm) has been successfully grown by molecular-beam epitaxy. It is a potential candidate of synthetic antiferromagnets due to antiferromagnetic coupling between Co2MnSi and MnGa, which is a promising skyrmion-racetrack-memory medium without skyrmion Hall effect after capping with a Pt layer. Unusual humps in transverse Hall resistance loops are clearly observed in the temperature range from 260 to 400 K. This anomaly is generally attributed to topological Hall effect, but other than that, we prove that non-uniform rotation of magnetic moments in the bilayer with magnetic field sweeping is also a possible mechanism contributed to the unusual hump.
Voltage-Driven Adaptive Spintronic Neuron for Energy-Efficient Neuromorphic Computing
Authors: Chen Ya-Bo , Yang Xiao-Kuo , Yan Tao , Wei Bo , Cui Huan-Qing , Li Cheng , Liu Jia-Hao , Song Ming-Xu , Cai Li
Published: July 2020

A spintronics neuron device based on voltage-induced strain is proposed. The stochastic switching behavior, which can mimic the firing behavior of neurons, is obtained by using two voltage signals to control the in-plane magnetization of a free layer of magneto-tunneling junction. One voltage signal is used as the input, and the other voltage signal can be used to tune the activation function (Sigmoid-like) of spin neurons. Therefore, this voltage-driven tunable spin neuron does not necessarily use energy-inefficient Oersted fields and spin-polarized current. Moreover, a voltage-control reading operation is presented, which can achieve the transition of activation function from Sigmoid-like to ReLU-like. A three-layer artificial neural network based on the voltage-driven spin neurons is constructed to recognize the handwritten digits from the MNIST dataset. For the MNIST handwritten dataset, the design achieves 97.75% recognition accuracy. The present results indicate that the voltage-driven adaptive spintronic neuron has the potential to realize energy-efficient well-adapted neuromorphic computing.
Influence of humidity, temperature and prestretch on the dielectric breakdown strength of silicone elastomer membranes for DEAs
Authors: Albuquerque Fabio Beco , Shea Herbert
Published: July 2020

Humidity, temperature and membrane prestretch influence the dielectric breakdown strength of elastomer membranes. These three factors thus also influence the maximum force and strain that dielectric elastomer actuators (DEAs) can generate, as the Maxwell pressure is proportional to the applied voltage squared, and limited by the breakdown field. We compared several commercial silicones, 10 to 25 µm thick under different equibiaxial prestretch conditions, for temperatures between 20 °C and 80 °C and relative humidity from 10% to 90%, measuring both breakdown fields and mechanical properties in order to compute two figures of merit for DEAs. The silicone films all have breakdown strengths of order 100 V µm−1. Higher humidity (90% RH) leads to decreased dielectric breakdown strengths compared to lower humidity (10% RH): up to 43% reduction for prestretches of 1.3 and 1.5, but only 2% to 10% reduction for prestretch of 1.1. Higher prestretch leads to up to 50% higher breakdown field, but also leads to higher effective Young’s modulus due to strain stiffening. Higher temperatures (80 °C) lead to up to 30% lower breakdown voltages compared to lower temperatures (20 °C). Higher prestretch generally enhances the maximum Maxwell stress because of higher dielectric breakdown strength, but reduces the strain figure of merit owing to increased Young’s moduli at high prestretch. For silicone elastomers, Sylgard 184 shows the highest stress figures of merit and LSR 4305 the highest strain figures of merit. Data for VHB is also presented for comparison. This work allows identifying elastomers better suited to harsh environments, and to selecting operating voltages that enable safe operation for a wide range of environmental conditions.
Quantum ekpyrotic mechanism in Fermi-bounce curvaton cosmology *
Authors: Addazi Andrea , Marciano Antonino
Published: July 2020

Within the context of the Fermi-bounce curvaton mechanism, we analyze the one-loop radiative corrections to the four-fermion interaction, generated by the non-dynamical torsion field in the Einstein-Cartan-Holst-Sciama-Kibble theory. We show that contributions that arise from the one-loop radiative corrections modify the energy-momentum tensor, mimicking an effective Ekpyrotic fluid contribution. Therefore, we call this effect quantum Ekpyrotic mechanism. This leads to the dynamical washing out of anisotropic contributions to the energy-momentum tensor, without introducing any new extra Ekpyrotic fluid. We discuss the stability of the bouncing mechanism and derive the renormalization group flow of the dimensional coupling constant ξ, checking whether any change of its sign takes place towards the bounce. This enforces the theoretical motivations in favor of the torsion curvaton bounce cosmology as an alternative candidate to the inflation paradigm.
Population scenarios for U.S. states consistent with shared socioeconomic pathways
Authors: Jiang Leiwen , O’Neill Brian C , Zoraghein Hamidreza , Dahlke Steve
Published: July 2020

There is a growing demand for subnational population projections for informing potential demographic influences on many aspects of society and the environment at the scale at which interactions occur and actions are taken. Existing US subnational population projections have not fully accounted for regional variations of demographic rates and therefore under-estimate the uncertainties in and heterogeneity of population trends. We present a first set of population projections for US states that span a wide but plausible range of population outcomes driven by changing state-level demographic rates consistent with the widely used SSP scenario framework. The projections are carried out for all 50 states integrated through bilateral gross migration flows. They update the original national-level SSP population projections based on recently available data and introduce more plausible assumptions on long-term international migration. We project a national population ranging from about 250–650 million by 2100, somewhat lower than the SSP projections due mainly to updated base year data. Utah and other states in the Rocky Mountain region see the largest increases in population in proportional terms, while the Northeast and Great Lakes regions see the slowest growth or most decline, along with individual states like Alaska, California, Louisiana, and Mississippi. Aging occurs in all states and scenarios, but is most prominent in the Northeast, Florida, and in some cases states in the West and the Great Lakes region. The relative contributions of fertility, mortality, and migration to population change varies substantially across states.
Community preparedness to flood disaster in Johor, Malaysia
Authors: Noor Diyana F. A. , Fakhru’l-Razi A. , Aini M. S. , Ahmad Azan R. , Mohd Muhaimin R. W.
Published: July 2020

Malaysia is a country that is affected by monsoonal floods yearly causing a significant amount of casualties, displacement of communities, damages to property and crops. The flood affects the community extensively and it is crucial for them to be prepared to reduce the risk faced in the event of a flood disaster. This study aims to determine the current level of flood preparedness amongst communities in Segamat, Johor as well as other contributing factors to preparedness such as attitude towards flood, risk perception, trust in agencies, sense of community and intention to prepare. A total of 22 villages were selected with the assistance of the District Office ensuring villages at risk were selected and a total of 150 self-administered questionnaires were distributed. Using descriptive analysis, the findings indicated that the other factors above were moderate to high and overall preparedness level was found to be moderately low. Measures taken by the respondents such as owning a first aid kit and financial preparedness such as purchasing property insurance and emergency savings were found to be much lower than other measures of preparedness.
Comparison of Rainfall Interpolation Methods in Langat River Basin
Authors: Hassim M , Yuzir A , Razali M N , Ros F C , Chow M F , Othman F
Published: July 2020

Rainfall is an element of climate that can be measured by a rain gauge. The rain gauge was set up for every station predefined by the Department of Irrigation and Drainage (DID) Malaysia. One millimeter (mm) of rainfall means that within a square meter of a flat surface, water can be as high as one mm. In the hydrology model, the rainfall data is very important in order to predict the flood or assist in the disaster mitigation plan. In this case, the availability of complete rainfall data in a region is essential. By performing spatial interpolation, rainfall data can predict values from the empty data at each point. In this study, Inverse Distance Weighting (IDW), Ordinary Kriging (OK), Simple Kriging (SK) and Kernel Smoothing (KS) method were considered in the rainfall interpolation for this area. Rainfall data at 20 points in Langat River Basin that obtained from DID Ampang for the period 2008–2017 were used as reference data. This study aimed to compare IDW, Kriging and Spline methods to obtain better interpolation methods. The interpolation is done by running a cross-validation using a geostatistical wizard in ArcGIS. The method effectiveness was evaluated by the calculation of mean error (ME), Root Mean Square Error (RMSE), Root mean Square Standardize Error (RMSSE) and Average Standard Error (ASE). For IDW method, only the ME and RMSE results are available. From the result, it can be seen that SK method outperforms the IDW, OK and KS method for these rainfall interpolations in Langat River Basin by showing better statistical evaluation.
Electrochemical removal of metoprolol using graphite-polyvinyl chloride composite as anode
Authors: Mussa Z H , Al-Qaim F F , Yuzir A , Shameli K
Published: July 2020

Metoprolol is one of pharmaceuticals that used for treatment of angina, heart failure, myocardial infarction, atrial fibrillation, atrial flutter and hypertensionand. It was frequently detected in wastewater samples. The application of graphite-PVC composite as anode was investigated for the degradation of metoprolol in the presence of strong electrolytes such as NaCl. The removal was strongly influenced by initial concentrations of metoprolol, NaCl and applied voltage. An initial concentration of 10 mg/L was eliminated more than 90% after 60 min under optimum conditions. The consumption energy of the electrochemical reaction was 0.665 Wh/mg while it was 2.717 Wh/mg for metoprolol in 0.5 g and 0.1 g NaCl, respectively at 5 V. The degradation results were monitored using liquid chromatography-time of flight/mass spectrometry.
Nanocellulose production from natural and recyclable sources: A review
Authors: Noor S M , Anuar A N , Tamunaidu P , Goto M , Shameli K , Halim M H Ab
Published: July 2020

Cellulose is the most abundant biopolymer on earth and is the chain of glucose residues that can be obtained easily from nature. Having unique material properties, nanocellulose has gained interest of researchers for various applications. Cellulose is generally known to exist in cell wall of a plant. However, this paper reviews the isolation of nanocellulose not only from plants, wood, and agroforestry residues, but also from recyclable sources paper waste and animals. With appropriate treatment and process (chemical, mechanical, and biological), reduction in diameter and length of cellulose up to nanoscale is possible. Nanocellulose may appear in its three main types namely cellulose nanofibers (CNFs), cellulose nanocrystals (CNCs) and bacterial nanocelluloses. Transformation of waste to wealth by adding value to waste and natural sources has become a meaningful and interesting work.
Diatomite carrier for rapid formation of Aerobic Granular Sludge
Authors: Basri H F , Anuar A N , Yuzir Ali , Halim Mohd Hakim Ab
Published: July 2020

Aerobic granular sludge (AGS) is a spherical compact sludge that has a lot of advantages such as great settling ability, high biomass level, good shock resistance and ability to withstand high organic loading rate (OLR) and toxic pollutants. However, it still has a major weakness that influences the low global reputation of AGS which is long granulation time. Therefore, a support material called diatomite which known for its unique characteristic is used in this study to speed up the granulation process in a pilot sequencing batch reactor (SBR) for domestic wastewater treatment. The AGS was cultivated in a pilot bioreactor for 30 days and measured for its characteristic. The result indicates fast granulation with 18 days of AGS formation period. Moreover, SEM images shows the present of diatomite in the inner part of the mature granules and proved its function as a nucleation agent that accelerate the aggregation process. The developed granules demonstrate excellent strength and settleability with strength (IC: 17.42%), SVI of 68 mL/g SS and settling velocity (114 m h−1) respectively.
Spatial Multi-Criteria for Wetland Site Restoration: A Case Study in Senibong Johor
Authors: Wahab YF. , Taib SM. , Karim H. , Baslan N.
Published: July 2020

Selecting sites for wetland can utilize a geographic information system (GIS) to assist in preliminary suitability analysis, in which sets of data can be quantified and aggregated to identify highly suitable wetland sites. Lunchoo River area are polluted at several points leads to the water pollution along the river and affect the source of income for Seletar people where improvement needed to avoid water pollution from becoming worse. This study focused on analyzing the land use along Lunchoo River using GIS analysis and locating the potential area for wetlands. Five sets of data were used in this suitability study, including hydrology, wetlands, soils, vegetation, and land use, all of which are key criteria for identifying suitable wetland sites. Methodology includes the creation of database, finding suitable location for the wetlands in a particular area using GIS analysis and types of wetlands suitable for particular location. Sampling location and non-point sources areas being map together with the results of water quality to show the class of water quality for each sampling station. The results of the site selection of wetland in Senibong Cove were overlay with the land use map to find whether the site selection is suitable for wetland area. Land use map is important to see the pattern around the sampling point which has high or low quality of water.
Application of carbon nanotubes and graphene to develop the heavy metal electrochemical sensor
Authors: Mustapa M A , Ambran Sumiaty , Yuzir Ali
Published: July 2020

Carbon nanotubes (CNTs) and graphene are carbon-based materials with great potential for electrochemical sensing in various applications such as for the environmental, biological, and physical sensors. For environmental applications, the sensor used to detect heavy metals such as cadmium (Cd), lead (Pb), mercury (Hg), iron (Fe), and other heavy metals that present in the water qualitatively and at the lowest limit of detection value. The uniqueness of their structures and chemical properties has attracted many researchers to develop carbon-based electrochemical sensors for environmental applications. These carbon materials are low-dimensional, thus providing the elevated aspect ratios and subsequently able to increase the sensitivity of the sensor probe. In the meantime, the graphene has its advantages in terms of its large surface area per unit volume to absorb and trap the molecules on the surface. In theory, the carbon atom is in the mid-range of electronegativity and can thus form a stable covalent bond with other molecules. These two materials are therefore consistent to bond with other functional groups such as amine, aldehyde, carboxyl, and thiol groups. All these functional groups can be functionalized with specific ligands or receptors for that particular heavy metal to provide specific and sensitive detection. Convenience in terms of their functionality, making them the center of attention as versatile platforms for functionalizing and designing an electrochemical sensor probe based on applications of concern. This paper focuses on reviewing carbon-based electrochemical sensors development to detect heavy metal in water for real-time monitoring of water quality, thus providing a brief overview of the sensor design reported previously.
Extreme wave loading on jacket structures
Authors: Cha J Y , Latheef M
Published: July 2020

Substructure load is sometimes the most concerned wave induced load exerting on jacket structures. In computing these loads, one of the most sensitive parameters is the characteristics of the waves hitting the structure. These waves which are usually modelled as regular waves, are in reality random in nature. The present study aims to quantify the changes on the substructure when nonlinear random waves are employed in the calculation of these forces. A simplified jacket structure located in a uni-directional wave field is considered in the present study. Also, in the computation of substructure loads, Morison’s equation is used. The wave loads simulated based on various wave theories are discussed in the present paper.