bluuebunny/crossref_metadata_2025 huggingface dataset:
Planarized spatially-regular arrays of spectrally uniform single quantum dots as on-chip single photon sources for quantum optical circuits
Authors: Zhang Jiefei , Huang Qi , Jordao Lucas , Chattaraj Swarnabha , Lu Siyuan , Madhukar Anupam
Published: November 2020

A long standing obstacle to realizing highly sought on-chip monolithic solid state quantum optical circuits has been the lack of a starting platform comprising scalable spatially ordered and spectrally uniform on-demand single photon sources (SPSs) buried under a planar surface. In this paper, we report on the first realization of planarized SPS arrays based on a unique class of shape-controlled single quantum dots (SQDs) synthesized on mesa top (dubbed MTSQDs) using substrate-encoded size-reducing epitaxy (SESRE) on spatially regular arrays of patterned nanomesas with edge orientation chosen to drive symmetric adatom migration from the nanomesa sidewalls to the top, thereby enabling spatially selective growth. Specifically, on GaAs(001) square nanomesas with edges along ⟨100⟩, we synthesized binary GaAs/InAs/GaAs MTSQDs emitting around 1120 nm with 1.8 nm standard deviation and single photon emission purity >99.5%. SESRE based MTSQDs are shown for the first time to lend themselves to planarization of the surface morphology when grown on pedestal shape mesas. We demonstrate that the planarizing overgrowth process over arrays of InGaAs SQDs largely maintains the SQDs’ high single photon emission purity (>98%) and spectral uniformity (∼5 nm). Such planarized SQD arrays offer the long-sought platform for on-chip integration with light manipulating structures to realize quantum optical circuits.
Non-monotonic double layers and electron two-stream instabilities resulting from intermittent ion acoustic wave growth
Authors: Vazsonyi Alexander R. , Hara Kentaro , Boyd Iain D.
Published: November 2020

Transient characteristics of a current-carrying plasma subjected to ion acoustic instability are studied via Vlasov–Poisson simulations. After saturation of the ion acoustic instability, when a sufficient range of long-wavelength ion acoustic modes is considered, ion acoustic wave packets form and give rise to ion phase space holes. These ion holes grow in magnitude until asymmetric electron reflection, due to the current carrying plasma, results in a potential gradient across the hole known as a non-monotonic double layer. Downstream of the double layer, an electron two-stream instability is generated due to a depletion of forward-streaming electrons by reflection. This secondary instability initiates a plasma wave whose phase velocity is determined by the magnitude of the double layer potential. While the double layer potential depends on the ion mass for a given domain length, the phase velocity of the secondary wave is consistently observed to be greater than the ion acoustic speed. Implications for the presence of these transient phenomena are discussed in the context of experimental plume measurements of hollow cathode devices.
A study on bubble nuclei population dynamics under reduced pressure
Authors: Yao Xiongliang , Li Zhipeng , Sun Longquan , Lu Hao
Published: November 2020

The existence of cavitation nuclei is one of the necessary conditions for liquid cavitation. Bubble nucleus is the most basic cavitation nucleus, and bubble nuclei size distribution is a parameter describing the population of gas nuclei. To study the dynamics of bubble nuclei population after artificial seeding under reduced pressure, a decompression chamber was built, combined with the artificial seeding system and the acoustic nuclei measurement system. After the nuclei seeding, the experimental study of the nuclei population dynamics with pressure and time was carried out. It is found that as the pressure decreases, the number density of larger size nuclei decreases, while the number density of smaller size nuclei increases. In the measured size range, the maximum value of number density of the nuclei size distribution increases. In addition, based on the theory of bubble dynamics, the growth process of the nucleus under reduced pressure is calculated and analyzed, which can realize the preliminary prediction of the nuclei population dynamics under reduced pressure.
Enhanced spin–orbit torque efficiency in Pt/Co/Ho heterostructures via inserting Ho layer
Authors: Jin Tianli , Law Wai Cheung , Kumar Durgesh , Luo Feilong , Wong Qi Ying , Lim Gerard Joseph , Wang Xuan , Lew Wen Siang , Piramanayagam S. N.
Published: November 2020

Spin–orbit torque (SOT) is a promising approach to manipulate the magnetization for high-performance spintronic applications. In conventional SOT heterostructures with heavy metal (HM)/ferromagnet layers, the SOT efficiency is determined by the charge-to-spin conversion, characterized by the spin Hall angle θSH of the HM layer. Researchers have investigated various HMs with different θSH to enhance the SOT efficiency while it is still limited because of the HM’s intrinsic properties. In this study, we employ a rare-earth holmium (Ho) layer on top of a ferromagnetic Co layer (Pt/Co/Ho) to enhance the SOT efficiency. An increased damping-like SOT efficiency up to 200% is achieved at an optimized thickness of 2-nm Ho, corresponding to a lower switching current density, which is 60% less compared to the sample without a Ho layer. The damping-like torque efficiency per current density is estimated at around 0.256 for Pt/Co/Ho heterostructures. Our results, herein, demonstrate that inserting a rare-earth metal affords an additional spin current and/or improves the spin transparency to enhance the SOT efficiency, providing a route for energy-efficient spintronic devices.
Spatial ecology and host diversity of three arboreal plants from Lord Howe Island
Authors: Dawes Thomas N. , Hutton Ian , Burns Kevin C.
Published: November 2020

In canopy ecology, it has long been understood that different guilds of arboreal plants have different spatial distributions and degrees of host specificity. Here, we present a case study looking at how within-crown spatial niche and host specificity vary between three very different morphologies of arboreal plant on Lord Howe Island, interpreting these in terms of different water acquisition strategies. We quantify within-crown spatial niche and created a null model to test host specificity in three species with very different water acquisition strategies (a mistletoe, an orchid and a detritus-collecting fern). The mistletoe had greater host specificity than the two epiphyte species, and was restricted to thinner branches. The fern occurred further from the outer crown than the other species including on the trunks of host trees, and was the only species to show no indication of host specificity. Differences in distribution are consistent with differences in water acquisition strategy, providing an initial link between traits and spatial distribution, a potentially fruitful avenue of future research.
Modular transient nanoclustering of activated β2-adrenergic receptors revealed by single-molecule tracking of conformation-specific nanobodies
Authors: Gormal Rachel S. , Padmanabhan Pranesh , Kasula Ravikiran , Bademosi Adekunle T. , Coakley Sean , Giacomotto Jean , Blum Ailisa , Joensuu Merja , Wallis Tristan P. , Lo Harriet P. , Budnar Srikanth , Rae James , Ferguson Charles , Bastiani Michele , Thomas Walter G. , Pardon Els , Steyaert Jan , Yap Alpha S. , Goodhill Geoffrey J. , Hilliard Massimo A. , Parton Robert G. , Meunier Frédéric A.
Published: November 2020

Significance

Proteins moving freely on the plasma membrane can become transiently trapped in functionally essential clusters. This capability is likely to be influenced by subtle conformational states of the protein promoting or preventing such confinement. The downside of conventional imaging of overexpressed tagged proteins is that it precludes selective tracking of inherently minor albeit functionally essential conformer populations. Intracellular expression of single-chain nanobodies allowed us to track endogenous proteins in highly specific conformational states in live cells and small organisms. We unveiled the full scope of nanoclustering behavior of β2-adrenergic receptors in various conformations, along with their transient nature. This technique is broadly applicable to other proteins and will help unravel essential dynamics and organization of nanoclusters.
TAO-kinase 3 governs the terminal differentiation of NOTCH2-dependent splenic conventional dendritic cells
Authors: Vanderkerken Matthias , Maes Bastiaan , Vandersarren Lana , Toussaint Wendy , Deswarte Kim , Vanheerswynghels Manon , Pouliot Philippe , Martens Liesbet , Van Gassen Sofie , Arthur Connie M. , Kirkling Margaret E. , Reizis Boris , Conrad Daniel , Stowell Sean , Hammad Hamida , Lambrecht Bart N.
Published: November 2020

Significance

Dendritic cells (DC) play a crucial role in the immune system by bridging innate and adaptive immunity. In the spleen, a specific subset of DCs accumulates around the blood-filtering marginal zone to capture particulate antigens such as red blood cells. We show here that these specialized DCs develop in response to NOTCH2 instruction that is regulated by a poorly studied kinase, called Thousand and One Kinase 3 (TAOK3). This kinase controls DC development in a cell-intrinsic manner, rendering cells receptive to NOTCH2 signaling. Interfering with this kinase opens up ways to manipulate a specific subset of DCs.
Machine-learning iterative calculation of entropy for physical systems
Authors: Nir Amit , Sela Eran , Beck Roy , Bar-Sinai Yohai
Published: November 2020

Significance

The calculation of entropy of a physical system is a fundamental step in learning its thermodynamic behavior. However, current methods to compute the entropy are often system specific and computationally costly. Here, we propose a method that is efficient, accurate, and general for computing the entropy of arbitrary physical systems. Our method is based on computing the mutual information between subsystems within the studied system, using a convolutional neural network. This iterative procedure provides accurate entropy evaluation for systems in and out of equilibrium.
Cosmic acceleration with torsion and non-metricity in Friedmann-like Universes
Authors: Iosifidis Damianos
Published: November 2020

Starting from the generalized Raychaudhuri equation with torsion and non-metricity, and considering an FLRW spacetime we derive the most general form of acceleration equation in the presence of torsion and non-metricity. That is we derive the cosmic acceleration equation when the non-Riemannian degrees of freedom are also taken into account. We then discuss some conditions under which torsion and non-metricity accelerate/decelerate the expansion rate of the Universe.
Broadband refractory plasmonic absorber without refractory metals for solar energy conversion
Authors: Wang Baoqing , Wang Wenhao , Ashalley Eric , Zhang Xutao , Yu Peng , Xu Hongxing , Wang Zhiming M
Published: November 2020

Electromagnetic wave absorbers with full-spectrum near-unity solar absorption are extremely desirable for solar energy conversion. Here, we theoretically proposed a broadband refractory plasmonic absorber without refractory metal, which has nearly perfect absorption over the whole solar spectrum. The absorber is supported by a periodic refractory dielectric framework of alumina and exhibits superior solar-selective and omnidirectional absorption. The simulated average absorption efficiency is up to 96% from 300 to 1400 nm, and the solar energy absorption efficiency can reach up to 90.8% over the entire solar spectrum range. Moreover, the steady-state temperature profile indicates that the absorber heats uniformly. The broadband refractory plasmonic absorber paves the way for the selective thermal absorption under high-temperature environment and holds great promise for solar energy harvesting and desalination applications.
A highly directional metamaterial-based terahertz circulator that does not require an external magnetic field
Authors: Xue Wei , Zhang Junying , Ma Jun-Wen , Hou Zhi-Ling , Zhao Quan-Liang , Xie Qing , Bi Song
Published: November 2020

Circulators, as passive non-reciprocal devices, have excellent potential for application in wireless communication and radar-signal processing. However, the construction of terahertz (THz)-frequency circulators is extremely difficult. Here, an electromagnetic matching model for metamaterials is proposed to support the design of a THz circulator with a wider operating bandwidth. The resulting circulator can work without an external magnetic field in the THz frequency range. The best isolation of this THz circulator is 20.9 dB, and its maximum directionality is 16.6 dB. These results validate a new method for the design of metamaterial-based THz devices.
High-pressure crystal structure and properties of BrCl
Authors: Zhang Lijuan , Bao Xin , Sun Ying , Ma Xinjun , Ou Tianji , Li Peifang
Published: November 2020

The pressure-induced phase transitions of bromine chloride (BrCl) were studied using the CALYPSO structure prediction method and first-principles calculations. Geometry optimization showed that the BrCl underwent the following phase transitions under high pressure: Cmcm → C2/m → Fddd → P4/mmm. These phase transitions occurred at 75, 94, and 140 GPa, respectively. All four phases were calculated to be dynamically stable, judging by the absence of any imaginary phonon modes in the whole Brillouin zone. As the pressure increased, the number of bonds between Br atom and surrounding Cl atoms increased. The high-pressure P4/mmm–BrCl phase (stable at 150 GPa) consisted of eight-coordinated Br atoms and is predicted to exist in BrCl compounds for the first time. The band overlap of the Cmcm phase, which caused the pressure-induced semiconductor → metal transition, occurs ∼50 GPa. This article lays the foundation for further theoretical and experimental research.
The pure and representative types of disordered platinum nanoparticles from machine learning
Authors: Parker Amanda J , Motevalli Benyamin , Opletal George , Barnard Amanda S
Published: November 2020

The development of interpretable structure/property relationships is a cornerstone of nanoscience, but can be challenging when the structural diversity and complexity exceeds our ability to characterise it. This is often the case for imperfect, disordered and amorphous nanoparticles, where even the nomenclature can be unspecific. Disordered platinum nanoparticles have exhibited superior performance for some reactions, which makes a systematic way of describing them highly desirable. In this study we have used a diverse set of disorder platinum nanoparticles and machine learning to identify the pure and representative structures based on their similarity in 121 dimensions. We identify two prototypes that are representative of separable classes, and seven archetypes that are the pure structures on the convex hull with which all other possibilities can be described. Together these nine nanoparticles can explain all of the variance in the set, and can be described as either single crystal, twinned, spherical or branched; with or without roughened surfaces. This forms a robust sub-set of platinum nanoparticle upon which to base further work, and provides a theoretical basis for discussing structure/property relationships of platinum nanoparticles that are not geometrically ideal.
Bioinspired PDMS-graphene cantilever flow sensors using 3D printing and replica moulding
Authors: Kamat Amar M , Zheng Xingwen , Jayawardhana Bayu , Kottapalli Ajay Giri Prakash
Published: November 2020

Flow sensors found in animals often feature soft and slender structures (e.g. fish neuromasts, insect hairs, mammalian stereociliary bundles, etc) that bend in response to the slightest flow disturbances in their surroundings and heighten the animal’s vigilance with respect to prey and/or predators. However, fabrication of bioinspired flow sensors that mimic the material properties (e.g. low elastic modulus) and geometries (e.g. high-aspect ratio (HAR) structures) of their biological counterparts remains a challenge. In this work, we develop a facile and low-cost method of fabricating HAR cantilever flow sensors inspired by the mechanotransductory flow sensing principles found in nature. The proposed workflow entails high-resolution 3D printing to fabricate the master mould, replica moulding to create HAR polydimethylsiloxane (PDMS) cantilevers (thickness = 0.5–1 mm, width = 3 mm, aspect ratio = 20) with microfluidic channel (150 μm wide × 90 μm deep) imprints, and finally graphene nanoplatelet ink drop-casting into the microfluidic channels to create a piezoresistive strain gauge near the cantilever’s fixed end. The piezoresistive flow sensors were tested in controlled airflow (0–9 m s−1) inside a wind tunnel where they displayed high sensitivities of up to 5.8 kΩ m s−1, low hysteresis (11% of full-scale deflection), and good repeatability. The sensor output showed a second order dependence on airflow velocity and agreed well with analytical and finite element model predictions. Further, the sensor was also excited inside a water tank using an oscillating dipole where it was able to sense oscillatory flow velocities as low as 16–30 μm s−1 at an excitation frequency of 15 Hz. The methods presented in this work can enable facile and rapid prototyping of flexible HAR structures that can find applications as functional biomimetic flow sensors and/or physical models which can be used to explain biological phenomena.
The spatial distribution of hydrogen and oxygen atoms in a cold atmospheric pressure plasma jet
Authors: Klose S-J , Ellis J , Riedel F , Schröter S , Niemi K , Semenov I L , Weltmann K-D , Gans T , O’Connell D , van Helden J H
Published: November 2020

Cold atmospheric pressure plasma jets (CAPJs) are an emerging technology for the localised treatment of heat sensitive surfaces. Adding humidity to the CAPJ’s feed gas yields an effective production of highly reactive intermediate species, such as hydrogen atoms, oxygen atoms, and hydroxyl radicals, among others, which are key species for biomedical applications. This study focusses on the effluent of the CAPJ kINPen, which was operated with argon feed gas and a humidity admixture of 3000 ppm, while a gas curtain was used to limit the diffusion of ambient air into the effluent. The axial and radial density distribution of O and H atoms is measured by means of picosecond two-photon absorption laser induced fluorescence spectroscopy (ps-TALIF). A maximum O atom density of (3.8 ± 0.7) × 1015 cm−3 and a maximum H atom density of (3.5 ± 0.7) × 1015 cm−3 are found at the nozzle of the plasma jet. The experimental results are compared to a two-dimensional reacting flow model that is coupled with a local zero-dimensional plasma chemical model. With this model, the main H and O atom production mechanisms are determined to be the dissociation of H2O and O2 in the plasma zone of the plasma jet. The latter indicates, that a significant amount of oxygen (1%) was present inside the device. The reaction of OH with O atoms represents the main consumption pathway for O atoms and is at the same time a significant production pathway for H atoms. The main consumption of H atoms is through a three-body reaction including O2 to form HO2, which consumes more H and O atoms to form OH. It is pointed out, that most of the species are produced in the plasma zone, and that O and H atoms, OH and HO2 radicals, and O2 and H2O molecules are strongly connected.
Evidence, origin and impact of liquid flows in plasma medicine in vitro treatments with APPJs
Authors: Stancampiano Augusto , Bocanegra Pablo Escot , Dozias Sébastien , Pouvesle Jean-Michel , Robert Eric
Published: November 2020

Plasma jets are being intensively studied for biomedicine applications but their fine control remains challenging due to the mutual interactions between plasma and target. Even considering one of the simplest scenario in a research laboratory, using a plasma jet to treat a 2D cells culture in a plastic multi-well plate, it is not known in detail how the physical environment of the micro-well may influence the nature of the plasma jet treatment. This study aims to shed light by investigating for the first time the liquid flows induced by the plasma treating a biologically-relevant liquid (e.g. PBS) in standard tissue culture grade multi well plates (i.e. 96, 24, 12 and 6 wells). Evaporation, induced by the anhydrous gas flow, is demonstrated to govern the thermal effect and be at the origin of the observed liquid cooling. Moreover, the formation of stable vortexes in the liquid induces a non-uniform distribution of plasma generated reactive species. This phenomenon, reported for various vessels and volumes of liquid, does not originate from thermal gradients but is instead the likely result of a combination of electrohydrodynamic forces and gas flow tangential components induced by the plasma impinging on the liquid surface.
Avalanche induced rapid impedance change and electron power absorption during gas breakdown under radio-frequency excitation
Authors: Liu Yong-Xin , Wang Xiang-Yu , Zhang Quan-Zhi , Donkó Zoltán , Zhao Kai , Schulze Julian , Wang You-Nian
Published: November 2020

During the initiation of a gas discharge under radio-frequency excitation we find that the system undergoes a sequence of distinct electron power absorption modes, while its impedance changes on the nanosecond timescale within the pre-breakdown, breakdown and post-breakdown phases. The experimental results for the spatiotemporal distribution of the excitation rate as well as other plasma parameters during the breakdown process are confirmed by particle-based kinetic simulations. The phenomenon is followed by an analytical model that sheds light on the temporal variation of the current and voltage waveforms as well as their phase difference leading to the rapid variation of the impedance during the build-up of the plasma.
Effects of emitting surfaces and trapped ions on the sheath physics and current flow in multidimensional plasma systems
Authors: Johnson G R , Campanell M D
Published: November 2020

Recent one-dimensional simulations of planar sheaths with strong electron emission have shown that trapping of charge-exchange ions causes transitions from space-charge limited (SCL) to inverse sheaths. However, multidimensional emitting sheath phenomena with collisions remained unexplored, due in part to high computational cost. We developed a novel continuum kinetic code to study the sheath physics, current flow and potential distributions in two-dimensional unmagnetized configurations with emitting surfaces. For small negatively biased thermionic cathodes in a plasma, the cathode sheath can exist in an equilibrium SCL state. The SCL sheath carries an immense density of trapped ions, neutralized by thermoelectrons, within the potential well of the virtual cathode. For further increases of emitted flux, the trapped ion cloud expands in space. The trapped ion space charge causes an increase of thermionic current far beyond the saturation limit predicted by conventional collisionless SCL sheath models without ion trapping. For sufficiently strong emission, the trapped ion cloud consumes the entire 2D plasma domain, forming a mode with globally confined ions and an inverse sheath at the cathode. In situations where the emitted flux is fixed and the bias is swept (e.g. emissive probe), the trapped ions cause a large thermionic current to escape for all biases below the plasma potential. Strong suppression of the thermionic emission, required for the probe to float, only occurs when the probe is above the plasma potential.
A theoretical analysis of steady three-dimensional flow and heat transfer of Power-Law nanofluid over a stretchable rotating disk filled with gyrotactic microorganisms
Authors: Usman  , Lin Ping , Ghaffari Abuzar , Mustafa Irfan
Published: November 2020

The current research study investigates the steady three-dimensional flow and heat transfer of a power-law nanofluid in the presence of the uniformly applied magnetic field and nonlinear thermal radiation over the stretchable rotating disk filled with gyrotactic microorganisms. The physically modeled partial differential equations (PDEs) are lessened to combined nonlinear ordinary differential equations (ODEs) with appropriate transformation. The influence of several types of pertinent parameters upon the dimensionless distributions of velocity, temperature, the concentration of nanoparticles, and microorganisms are analyzed graphically by solving the ODEs with a well-known shooting method. The tabular comparison is provided for the verification between the present results with those in the literature. Also, the physical quantities of interest are calculated, and the effects are scrutinized. Furthermore, it is noticed that the emerging parameters have produced a significant influence upon the velocity components, temperature, concentration of nanoparticles, and motile density of microorganisms.
Unraveling the effect of the defect and adsorbate on the magnetic properties of χ
3 borophene nanoribbons: an in-silico study
Authors: Molaeezadeh Seyyedeh Fatemeh , Shadman Lakmehsari Mohammad , Arabieh Masoud , T. Azar Yavar
Published: November 2020

The synthesis and characterization of borophene-based nanostructures have attracted researchers’ interest in several related fields. The diversity of geometric structures based on borophene presents a broad category of applications ranging from biomedical technology to spintronics. Here, the configurational dependence of χ
3 borophene magnetic and electronic properties was examined systematically based on spin-polarized density functional theory. Our results show that vacancy defects and their distribution over the borophene play a vital role in the structure magnetization. A tight correlation between the edge geometry and total magnetism was observed. The spin polarization was attributed to the quasi-localized states at the edge atoms. The inspection of individually plausible adsorption modes of a typical organic molecule on nanoribbon unraveled a strong dependence between magnetic moment and adsorption mode.
Automated detection of ripple oscillations in long-term scalp EEG from patients with infantile spasms
Authors: McCrimmon Colin M , Riba Aliza , Garner Cristal , Maser Amy L , Phillips Donald J , Steenari Maija , Shrey Daniel W , Lopour Beth A
Published: November 2020

Objective. Scalp high-frequency oscillations (HFOs) are a promising biomarker of epileptogenicity in infantile spasms (IS) and many other epilepsy syndromes, but prior studies have relied on visual analysis of short segments of data due to the prevalence of artifacts in EEG. Here we set out to robustly characterize the rate and spatial distribution of HFOs in large datasets from IS subjects using fully automated HFO detection techniques. Approach. We prospectively collected long-term scalp EEG data from 12 subjects with IS and 18 healthy controls. For patients with IS, recording began prior to diagnosis and continued through initiation of treatment with adrenocorticotropic hormone (ACTH). The median analyzable EEG duration was 18.2 h for controls and 84.5 h for IS subjects (∼1300 h total). Ripples (80–250 Hz) were detected in all EEG data using an automated algorithm. Main results. HFO rates were substantially higher in patients with IS compared to controls. In IS patients, HFO rates were higher during sleep compared to wakefulness (median 5.5 min−1 and 2.9 min−1, respectively; p = 0.002); controls did not exhibit a difference in HFO rate between sleep and wakefulness (median 0.98 min−1 and 0.82 min−1, respectively). Spatially, IS patients exhibited significantly higher rates of HFOs in the posterior parasaggital region and significantly lower HFO rates in frontal channels, and this difference was more pronounced during sleep. In IS subjects, ACTH therapy significantly decreased the rate of HFOs. Significance. Here we provide a detailed characterization of the spatial distribution and rates of HFOs associated with IS, which may have relevance for diagnosis and assessment of treatment response. We also demonstrate that our fully automated algorithm can be used to detect HFOs in long-term scalp EEG with sufficient accuracy to clearly discriminate healthy subjects from those with IS.
Scaling properties of flow harmonics of deuterons and protons in Au+Au reactions at 1.23 AGeV
Authors: Hillmann Paula , Steinheimer Jan , Reichert Tom , Gaebel Vincent , Bleicher Marcus , Sombun Sukanya , Herold Christoph , Limphirat Ayut
Published: November 2020

We explore the scaling properties of the elliptic and quadrangular flow of deuterons and protons in Au+Au reactions at a beam energy of 1.23 AGeV within the UrQMD approach. These investigations are of great interest for the HADES experiment at GSI that has recently studied the flow of light nuclei. In the present studies, deuterons are formed via phase-space coalescence. Our results agree well with the experimental data, if for this low energy a hard equation of state is considered. We observe that protons and deuterons show direct scaling with the mass number A. We also see scaling of higher order flow harmonics, e.g. υ4 ∼

υ
2
2

.
Studies of hyperon production in HADES at FAIR-Phase0 — the case of an inclusive Σ(1385)+ measurement in pp reaction
Authors: Kuboś Joanna , Lalik Rafal
Published: November 2020

In this proceedings first results of an inclusive measurement of the Σ(1385) + resonance produced in the proton-proton reaction at the beam kinetic energy of 3.5 GeV are presented. Mass of the Σ(1385)+ resonance extracted from a fit with the Breit-Wigner function is found to be M0
= 1380.02 MeV with a fixed width of Γ = 40MeV resulting from the previous exclusive measurements done by HADES. The presented analysis is a first trial to obtain the inclusive cross section for the production of the first-excited state of the Σ hyperon in elementary collisions at SIS energy range. The inclusive cross section is important for studies of the hyperon electromagnetic decays, which are one of the main fields of interest of the HADES experimental program during the FAIR-Phase0.
Development of Forward Tracker
Authors: Malige A , Korcyl G , Lalik R , Salabura P , Rathod N
Published: November 2020

The High Acceptence DiElectron Spectrometer has experienced many years of successful operation which revealed high capability of measuring resonance production in proton-proton and pion-proton reactions. Since many of the production channels that are crucial for the understanding of the resonance production are highly anisotropic, that a large part of the signal would be located in the most forward and backward phase space regions, a new opportunity to an upgrade to the detector for improving the phase-space acceptance in this region has been proposed. The Forward Tracker (FT) will cover the polar angle in the detector system between 0°and 6.5°, which significantly will increase the detection acceptance. The FT is in construction with the synergy with PANDA Central Tracker, and is realized by groups from Jagellionian University, FZ Jülich and LIP Coimbra. The development of the new and faster readout electronics (DAQ) to cope with higher data rates, track reconstruction and the results from the beam time at Forschungszentrum Jülich are discussed.
The strange charm of hyperons
Authors: Schönning K
Published: November 2020

In these proceedings, the merits of hyperons as a diagnostic tool will be outlined. Hyperons shed light on some of the most challenging problems of contemporary physics: the strong interaction in the confinement domain and the matter-antimatter asymmetry of the Universe. Recent progress will be reviewed and future prospects at world-wide facilities will be summarised.
LUE-200 Accelerator—A Photo-neutron Generator For The Pulsed Neutron Source “IREN”
Authors: Sumbaev A. , Kobets V. , Shvetsov V. , Dikansky N. , Logatchov P.
Published: November 2020

This article reports about the construction and status of the accelerator facility at the Laboratory of Neutron Physics (FLNP) in the Joint Institute for Nuclear Research (JINR, Dubna), the driver of an intense pulsed resonance neutron source. The general scheme of the electron linear accelerator and features of its basic systems are presented. LUE-200 consists of two accelerating sections on a traveling wave with an operating frequency of 2856 MHz with RF power compression systems of the SLED type. The pulse current of the beam at the output of the accelerator reaches 2 A with a pulse duration of 80–100 ns. At the average energy of beam particles from 60–65 MeV and a cycle repetition rate of 50 Hz, the average beam power reaches ≈ 600 W. The integral neutron flux from the non-multiplying target reaches ∼ 1012 s−1.
Diagnosis of environmental controls on daily actual evapotranspiration across a global flux tower network: the roles of water and energy
Authors: Han Qiong , Liu Qin , Wang Tiejun , Wang Lichun , Di Chongli , Chen Xi , Smettem Keith , Singh Shailesh Kumar
Published: November 2020

Relative contributions from environmental factors to daily actual evapotranspiration (ETa) across a variety of climate zones is a widely open research question, especially regarding the roles played by soil water content ((SWC); water supply) and net radiation ((Rn); energy supply) in controlling ETa. Here, the boosted regression tree method scheme was employed to quantify environmental controls on daily ETa using the global FLUXNET dataset. Similar to the general trend suggested by the Budyko theory at annual scales, the results showed that the relative control of SWC on daily ETa increased with increasing aridity index (Φ); however, Rn played a major role at most FLUXNET sites (roughly Φ < 4), indicating that Rn could be a leading control on daily ETa even at water-limited sites. The variability in the relative controls of SWC and Rn also partly depended on factors affecting water availability for daily ETa (e.g. vegetation characteristics and groundwater depth). Our study showed that other than SWC and Rn, the net effect of environmental controls (particularly leaf area index) on daily ETa was more important at drier sites than at relatively humid sites. This suggests that near-surface hydrological processes are more sensitive to vegetation variations due to their ability to extract deep soil water and enhance ETa, especially under arid and semi-arid climatic conditions. Our findings illustrate how environmental controls on daily ETa change as the climate dries, which has important implications for many scientific disciplines including hydrological, climatic, and agricultural studies.
Polyanalytic reproducing Kernels on the quantized annulus
Authors: Demni Nizar , Mouayn Zouhair
Published: November 2020

While dealing with the constant-strength magnetic Laplacian on the annulus, we complete Peetre’s work. In particular, the eigenspaces associated with its discrete spectrum true turns out to be polyanalytic spaces with respect to the invariant Cauchy–Riemann operator, and we write down explicit formulas for their reproducing kernels. When the magnetic field strength is an integer, we compute the limits of the obtained kernels when the outer radius of the annulus tends to infinity and express them by means of the fourth Jacobi theta function and of its logarithmic derivatives. Under the same quantization condition, we also derive their transformation rule under the action of the automorphism group of the annulus.
Beating the Rayleigh limit via aperture modulation
Authors: Xu Biao , Wang Zhiqiang , He Jinping
Published: November 2020

We demonstrate theoretically and experimentally a method to break the Rayleigh limit of an imaging system by modulating only the aperture of the imaging optics. By fully utilizing the useful information extracted from an image sequence, a superresolution image with high-frequency components beyond the cutoff frequency of the imaging system is reconstructed. Resolution enhancement of

>

2 times is achieved experimentally. Simulation results show that the method can still work with the signal-to-noise ratio of ~ 10 for the acquired images.
Increasing the brightness of harmonic XUV radiation with spatially-tailored driver beams
Authors: Treacher D J , Lloyd D T , O’Keeffe K , Wiegandt F , Hooker S M
Published: November 2020

Bright high harmonic sources can be produced by loosely focussing high peak power laser pulses to exploit the quadratic scaling of flux with driver spot size at the expense of a larger experimental footprint. Here, we present a method for increasing the brightness of a harmonic source (while maintaining a compact experimental geometry) by spatially shaping the transverse focal intensity distribution of a driving laser from a Gaussian to supergaussian. Using a phase-only spatial light modulator we increase the size and order of the supergaussian focal profiles, thereby increasing the number of harmonic emitters more efficiently than possible with Gaussian beams. This provides the benefits of a loose focussing geometry, yielding a five-fold increase in harmonic brightness, whilst maintaining a constant experimental footprint. This technique can readily be applied to existing high harmonic systems, opening new opportunities for applications requiring bright, compact sources of coherent short wavelength radiation.
Effects of porosity on the mechanical properties of additively manufactured components: a critical review
Authors: Al-Maharma Ahmad Y , Patil Sandeep P , Markert Bernd
Published: November 2020

In the present review, the effect of porosity on the mechanical properties of the fabricated parts, which are additively manufactured by powder bed fusion and filament extrusion-based technologies, are discussed in detail. Usually, additive manufacturing (AM) processes based on these techniques produce the components with a significant amount of pores. The porosity in these parts typically takes two forms: pores with irregular shapes (called keyholes) and uniform (spherical) pores. These pores are present at different locations, such as surface, sub-surface, interior bulk material, between the deposited layers and at filler/matrix interface, which critically affect the corrosion resistance, fatigue strength, stiffness, mechanical strength, and fracture toughness properties, respectively. Therefore, it is essential to study and understand the influence of pores on the mechanical properties of AM fabricated parts. The technologies of AM can be employed in the manufacturing of components with the desired porous structure through the topology optimization process of scaffolds and lattices to improve their toughness under a specific load. The undesirable effect of pores can be eliminated by using defects-free raw materials, optimizing the processing parameters, and implementing suitable post-processing treatment. The current review grants a more comprehensive understanding of the effect of porous defects on mechanical performance and provides a mechanistic basis for reliable applications of additively manufactured components.
Structural evolution across the metal-insulator transition of strongly distorted Lu1−xScxNiO3 perovskites (x = 0, 0.1, 0.2)
Authors: Cui Qi , Wang Ningning , Alonso Jose A , Fauth François , Cheng Jinguang
Published: November 2020

RNiO3 perovskites have been described to present thermally driven metal-insulator transitions (at TMI) as a function of the rare-earth ion size (R = Pr to Lu). Aiming to extend the stability range of RNiO3 for smaller R3+ ions, we prepared Lu1−xScxNiO3 (x = 0, 0.1, 0.2) perovskites, being Sc3+ ions substantially smaller than Lu3+, by using a multi-anvil high-pressure synthesis device at 10 GPa. We have studied the structural evolution of Lu0.9Sc0.1NiO3 by synchrotron x-ray diffraction (SXRD) from room temperature to 350 °C. The symmetry of the lattice evolves from monoclinic (P2
1
/n) to orthorhombic (Pbnm) upon heating across TMI (≈320 °C), with the existence of two chemically and crystallographically distinct nickel sites in the insulating, monoclinic regime, whereas the metallic phase has a single NiO6 environment. A simultaneous structural and electronic transition implies an abrupt evolution of the lattice parameters and size of the NiO6 octahedra upon entering the metallic regime, leading to the merging of the disproportionated Ni-O bond lengths. The magnetic properties correspond to the establishment of antiferromagnetic correlations at the Ni sublattice; a decrease of the TN ordering temperature from 122 K (x = 0) to 113 K (x = 0.2) is observed as the Sc content increases, which is concomitant with a more distorted perovskite structure.
Selective laser sintering of conductive patterns on a novel silver–barium strontium titanate composite material
Authors: Ranasingha Oshadha K , Luce Andrew , Strack Guinevere , Hardie Cameron , Piro Yuri , Haghzadeh Mahdi , Sobkowicz Margaret J , Kingsley Edward , Armiento Craig , Akyurtlu Alkim
Published: November 2020

Here, we report a previously un-reported printed electronics/additive manufacturing (AM) approach to fabricate conductive/resistive features on novel insulating silver–barium strontium titanate (Ag–BST) printed composite films. Ag–BST composite functional ink was formulated by blending a conductive Ag nanoparticle ink and an insulating BST nanoparticle ink. The blending ratio of Ag and BST inks was optimized to obtain the insulating phase after the initial curing and the conductive/resistive phase following selective laser sintering under ambient conditions. Selective laser sintered Ag–BST resistors showed an ohmic behavior and the resistivity could be adjusted by varying the laser sintering parameters, such as the wavelength, power and the rastering speed/pitch of the laser. This insulator to conductor/resistor transitioning Ag–BST ink paves a new path for direct write printed electronics/AM applications. Proofs of concept for potential applications utilizing this functional ink are demonstrated. Also, this Ag–BST ink can be used as a conventional resistive ink for dispensing printers. Thermally sintered Ag–BST resistors showed less than 8% variation in resistance between −50 °C and 150 °C.
Surface energy patterning for ink-independent process optimization of inkjet-printed electronics
Authors: Schlisske Stefan , Raths Sebastian , Ruiz-Preciado Luis A , Lemmer Uli , Exner Kai , Hernandez-Sosa Gerardo
Published: November 2020

The applicability of inkjet-printed (opto-)electrical devices are hindered by their low lateral resolution, when compared to conventional techniques. The low lateral resolution is mainly caused by the flow and spreading of the functional ink on the substrate, which is determined by the substrate-ink-interaction. Recent approaches, that confine and control the spreading, have been developed. However, they suffer from low lateral resolution or the usage of physical barriers. The later needs an adjustment of the ink or may contain an overlaid height information. Both cases are not always applicable when fabricating functional devices. Herein, we report the utilization of a surface energy patterning approach based on siloxane self-assembled monolayers. The obtained energetic differences control the flow and suppress the spreading of the ink, without creating the necessity to alter the ink composition. Furthermore this approach leads to an improved structural fidelity and printing resolution of arbitrary shapes. With that, we were able to print silver- and gold-electrodes for organic filed-effect transistors with a channel length of <25 µm, fabricating feature sizes below the footprint of a single drop. The electrical characterization of these transistors revealed that the utilization of this surface energy patterning has no negative influence on the device performance. The introduced approach facilitates the process development and improves the quality and resolution of printed features. This will facilitate the fabrication of high-quality and high resolution printed electronic devices.
Accuracy assessment of fringe projection profilometry and digital image correlation techniques for three-dimensional shape measurements
Authors: Nguyen Hieu , Liang Jiali , Wang Yuzeng , Wang Zhaoyang
Published: November 2020

With ever-increasing demand for three-dimensional (3D) imaging and shape measurements in a variety of fields, measurement accuracy has become of vital importance to numerous scientific and engineering applications. This paper presents an experimental investigation into the accuracy comparison of two prevalent 3D imaging and shape measurement methods: fringe projection profilometry (FPP) and 3D digital image correlation (3D-DIC) techniques. A detailed description of their principles reveals their inherent similarities and fundamental differences. A measurement system composed of both techniques is employed in the study, and a test target with speckle checkerboard patterns on its surface is adopted to allow simultaneous FPP and 3D-DIC measurements. The evaluation puts emphasis on how the geometric angles between key hardware components affect the 3D measurement accuracy. Experiments show that the depth and height measurements of both techniques can reach sub-micron accuracy, and the relative accuracy of the 3D shape or position measurements can reach 1/600 000.
Laser metal deposition of refractory high-entropy alloys for high-throughput synthesis and structure-property characterization
Authors: Dobbelstein Henrik , George Easo P , Gurevich Evgeny L , Kostka Aleksander , Ostendorf Andreas , Laplanche Guillaume
Published: November 2020

Progress in materials development is often paced by the time required to produce and evaluate a large number of alloys with different chemical compositions. This applies especially to refractory high-entropy alloys (RHEAs), which are difficult to synthesize and process by conventional methods. To evaluate a possible way to accelerate the process, high-throughput laser metal deposition was used in this work to prepare a quinary RHEA, TiZrNbHfTa, as well as its quaternary and ternary subsystems by in-situ alloying of elemental powders. Compositionally graded variants of the quinary RHEA were also analyzed. Our results show that the influence of various parameters such as powder shape and purity, alloy composition, and especially the solidification range, on the processability, microstructure, porosity, and mechanical properties can be investigated rapidly. The strength of these alloys was mainly affected by the oxygen and nitrogen contents of the starting powders, while substitutional solid solution strengthening played a minor role.
Higher-order models capture changes in controllability of temporal networks
Authors: Zhang Yan , Garas Antonios , Scholtes Ingo
Published: November 2020

In many complex systems, elements interact via time-varying network topologies. Recent research shows that temporal correlations in the chronological ordering of interactions crucially influence network properties and dynamical processes. How these correlations affect our ability to control systems with time-varying interactions remains unclear. In this work, we use higher-order network models to extend the framework of structural controllability to temporal networks, where the chronological ordering of interactions gives rise to time-respecting paths with non-Markovian characteristics. We study six empirical data sets and show that non-Markovian characteristics of real systems can both increase or decrease the minimum time needed to control the whole system. With both empirical data and synthetic models, we further show that spectral properties of generalisations of graph Laplacians to higher-order networks can be used to analytically capture the effect of temporal correlations on controllability. Our work highlights that (i) correlations in the chronological ordering of interactions are an important source of complexity that significantly influences the controllability of temporal networks, and (ii) higher-order network models are a powerful tool to understand the temporal-topological characteristics of empirical systems.