bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical investigation of the natural transition in flat-plate boundary layers on superhydrophobic surfaces considering the influence of the leading edge region
Authors: Liu Bin , Zhang Yongming
Published: March 2022

The natural transition in flat-plate boundary layers on superhydrophobic surfaces is studied while considering the influence of the leading edge region. A method for calculating basic laminar flow on superhydrophobic surfaces while considering the influence of the leading edge region is proposed, which accurately obtains the flow field in the whole computational domain from the leading edge region to the downstream region with acceptable computational load. The results obtained by this method are compared to those ignoring the influence of the leading edge region, such that this influence can be seen. The influence decreases the thickness of the laminar boundary layers on superhydrophobic surfaces and increases the slip velocity on the wall. The linear stability of the boundary layers is also analyzed. The influence of the leading edge region delays the critical location of flow instability on superhydrophobic surfaces and narrows the unstable zone. The eN method is used to predict the transition locations. The influence of the leading edge region further delays the transition location, and the transition delay effect becomes stronger as the slip length or the oncoming flow velocity increases. Furthermore, a method for predicting the spectrum of wall fluctuating pressure in the laminar flow region over underwater vehicles is proposed. At the downstream region, the amplitude of the wall fluctuating pressure increases and the frequency range decreases. Superhydrophobic surfaces suppress the wall fluctuating pressure, and the influence of the leading edge region enhances this suppression effect.
Structural, dielectric and electro-caloric properties of Ba(Ti,Zr)O3-(La,Sr)MnO3 composite multiferroic
Authors: Gaur Anshu , Srinath S.
Published: March 2022

Dielectric and electrocaloric (EC) properties of sol-gel synthesized BaTi0.84Zr0.16O3 (BTZ) and La0.78Sr.0.22MnO3 (LSM) composite in 80:20 molar ratio is reported. We discuss the dielectric analysis based on the electric modulus M*(=1/ϵ*) with the aim to differentiate the orientational and interfacial/carrier contribution and to explain their temperature and frequency dependence. Frequency dependence of imaginary part of M, i.e., M″(ω) of the composite exhibits a broad relaxation peak in MHz range while ϵ″(ω) graph is typical of interfacial/carrier polarization dominated: ϵ″ is as high as 7k at 20 Hz, decreases to 300 at 2 MHz measured at 25°C. M″-max shifts to higher frequencies with the increase in the temperature. The M″-peak, associated with BTZ-dipoles, is fitted using Cole-Cole (CC) equation to estimate the dielectric parameters, static and high-frequency dielectric constants ϵs and ϵꝏ respectively, relaxation time, τ, and the CC parameter, α, which is related to the distribution of relaxation time. Temperature dependence of physical parameters obtained from the fitting reflected the attributes of orientational polarization of the parent BTZ. These analyses indicate that M* is a more suitable parameter to consider for the ferroelectric-ferromagnetic composites.
Responses of grass productivity traits to bush clearing in semi-arid rangelands in North-West Province of South Africa
Authors: Mndela Mthunzi , Madakadze Ignacio C. , Tjelele Julius T. , Mangwane Mziwanda , Nherera-Chokuda Florence , Dube Sikhalazo , Ramoelo Abel , Letsoalo Ngoako L.
Published: March 2022

Woody plant encroachment threatens herbaceous plant productivity in many rangelands globally. We evaluated the impact of bush clearing on grass tiller, leaf and biomass production, and tuft sizes in the Kgomo-kgomo and Makapaanstad rangelands in North-West Province, South Africa. In each rangeland, the number of tillers and leaves, tuft sizes and biomass of eight dominant grass species were recorded in bush-cleared and uncleared treatments. The treatment and species interacted significantly (P < 0.001) for tiller and leaf production and tuft sizes. Bush clearing increased tiller production of bunch grasses but not stoloniferous grasses. At Kgomo-kgomo, bunch grasses (Panicum maximum (Jacq.) and Urochloa mosambicensis (Hack.) Dandy] had three to six times more tillers and leaves per plant in the cleared than uncleared treatment. At Makapaanstad, only annual bunch grasses [Brachiaria eruciformis (Sibth. & Sm.) Griseb and Tragus berteronianus (Schult.)] attained twice as many tillers and leaves per plant in the cleared compared to uncleared treatment. Biomass was 1776 ± 159 and 696 ± 159 g m−2 in cleared and uncleared treatments respectively at Kgomo-kgomo and 1358 ± 258 and 1089 ± 258 g m−2 at Makapaanstad. The tufts of bunch grasses were nearly twice as large in the cleared compared with the uncleared treatment at Kgomo-kgomo, whereas only stoloniferous grass tufts increased at Makapaanstad. Overall, bush clearing improved grass productivity and performance, but the responses varied by species.
Prevention of the foreign body response to implantable medical devices by inflammasome inhibition
Authors: Barone Damiano G. , Carnicer-Lombarte Alejandro , Tourlomousis Panagiotis , Hamilton Russell S. , Prater Malwina , Rutz Alexandra L. , Dimov Ivan B. , Malliaras George G. , Lacour Stephanie P. , Robertson Avril A. B. , Franze Kristian , Fawcett James W. , Bryant Clare E.
Published: March 2022

Significance

Implantable electronic medical devices (IEMDs) are used for some clinical applications, representing an exciting prospect for the transformative treatment of intractable conditions such Parkinson’s disease, deafness, and paralysis. The use of IEMDs is limited at the moment because, over time, a foreign body reaction (FBR) develops at the device–neural interface such that ultimately the IEMD fails and needs to be removed. Here, we show that macrophage nucleotide-binding oligomerization domain-like receptor family pyrin domain containing 3 (NLRP3) inflammasome activity drives the FBR in a nerve injury model yet integration of an NLRP3 inhibitor into the device prevents FBR while allowing full healing of damaged neural tissue to occur.
Applications of micro- and macroalgae elements in the food and healthcare industries
Authors: Sarvananda L. , Premarathna Amal D. , Shafras Mohamed
Published: March 2022

Algae are a great source of mineral salts, vitamins, proteins and trace metals necessary for human metabolism. Interest of introducing algae into human nutrition in western countries has increased in recent years. Humans can also consume algae indirectly because they are a source of different compounds used in the food industry such as agar, alginate, carrageenan, furcellaran, mannitol, pigments and fatty acids. These compounds are mainly utilized in the pharmaceutical and food industries with immense importance. In recent years, the application of algae extracts plays a major role as fertilizers in the enhancement of plant growth in agriculture industry. This review discusses the micro- and macroalgae applications in the industries for human and animal consumption, besides the use of algae extracts for the production of fertilizers.
Assessing the Thermal Stability of Toolmarks Casting Materials through Optical Comparison Microscopy, Virtual Comparison Microscopy and Quantitative Similarity Scores
Authors: Koh Alaric C. W. , Yeoh Kai Yuan
Published: March 2022

Toolmarks, particularly those found on bulky, inaccessible or immovable items, can be recovered by casting. To allow for subsequent comparative examinations, the casting material, typically polysiloxanes or silicones, must be able to capture and preserve fine details within a toolmark accurately. To study the stability of such details after exposure to heat, toolmark casts were heated at either 60 °C for 2 h, or 90 °C for 1 h. These casts were subsequently compared to casts that had not been exposed to heat, using traditional optical comparison microscopy, as well as virtual comparison microscopy. Digitised toolmark signatures were also extracted from the casts and compared pairwise to obtain quantitative similarity scores based on cross-correlation, consecutive matching striae and Mann-Whitney U-statistic. Our results show that the fine surface details captured on all four commercial toolmark casting materials tested herein remained stable after exposure to heat. This study shows that the above heating protocols are viable viral inactivation methods for toolmark casts that are potentially contaminated with human coronaviruses, such as SARS-CoV-2. Our findings also apply to other scenarios, such as for casts that were left in a vehicle parked under the sun.
Why are you talking with snakes? To get new evolutionary insights in cardiac electrophysiology!
Authors: Brette Fabien , Le Guennec Jean-Yves , Thireau Jérôme
Published: March 2022

Brette, Le Guennec, and Thireau discuss recent findings on evolutionary cardiac electrophysiology.
Design optimization of an electron-to-photon conversion target for ultra-high dose rate x-ray (FLASH) experiments at TRIUMF
Authors: Esplen Nolan , Egoriti Luca , Paley Bill , Planche Thomas , Hoehr Cornelia , Gottberg Alexander , Bazalova-Carter Magdalena
Published: March 2022

Objective. To develop a bremsstrahlung target and megavoltage (MV) x-ray irradiation platform for ultrahigh dose-rate (UHDR) irradiation of small-animals on the Advanced Rare Isotope Laboratory (ARIEL) electron linac (e-linac) at TRIUMF. Approach. An electron-to-photon converter design for UHDR radiotherapy (RT) was centered around optimization of a tantalum–aluminum (Ta–Al) explosion-bonded target. Energy deposition within a homogeneous water-phantom and the target itself were evaluated using EGSnrc and FLUKA MC codes, respectively, for various target thicknesses (0.5–1.5 mm), beam energies (E
e− = 8, 10 MeV) and electron (Gaussian) beam sizes (

2
σ

= 2–10 mm). Depth dose-rates in a 3D-printed mouse phantom were also calculated to infer the compatibility of the 10 MV dose distributions for FLASH-RT in small-animal models. Coupled thermo-mechanical FEA simulations in ANSYS were subsequently used to inform the stress–strain conditions and fatigue life of the target assembly. Main results. Dose-rates of up to 128 Gy s−1 at the phantom surface, or 85 Gy s−1 at 1 cm depth, were obtained for a 1 × 1 cm2 field size, 1 mm thick Ta target and 7.5 cm source-to-surface distance using the FLASH-mode beam (E
e− = 10 MeV, 2

σ

= 5 mm, P = 1 kW); furthermore, removal of the collimation assembly and using a shorter (3.5 cm) SSD afforded dose-rates >600 Gy s−1, albeit at the expense of field conformality. Target temperatures were maintained below the tantalum, aluminum and cooling-water thresholds of 2000 °C, 300 °C and 100 °C, respectively, while the aluminum strain behavior remained everywhere elastic and helped ensure   the converter survives its prescribed 5 yr operational lifetime. Significance. Effective design iteration, target cooling and failure mitigation have culminated in a robust target compatible with intensive transient (FLASH) and steady-state (diagnostic) applications. The ARIEL UHDR photon source will facilitate FLASH-RT experiments concerned with sub-second, pulsed or continuous beam irradiations at dose rates in excess of 40 Gy s−1.
Plasma-relevant fast electron impact study of trifluoromethane
Authors: Wang Dong-Hui , Wang Shu-Xing , Nie Zhi-Wei , Wang Li-Han , Xu Yuan-Chen , Du Xiao-Jiao , Zhu Lin-Fan
Published: March 2022

Trifluoromethane is an important etching gas in semiconductor industries as the fluorine source in reactive etching plasma. Electron impact excitations into the dissociation states are essential for plasma modeling. By employing an angle-resolved electron energy loss spectrometer, the generalized oscillator strengths (GOSs) for the valence-shell excited states have been determined at an absolute scale utilizing the crossed-beam based relative flow technique. The measurement was performed with an incident electron energy of 1500 eV at an energy resolution of about 70 meV. The corresponding optical oscillator strengths are also obtained by extrapolating the measured GOSs to the limit of zero momentum transfer. The extrapolated data and fitted linewidths are used to reproduce the photoabsorption spectra and compare with the available experimental and theoretical results. In addition, the integral cross sections from the excitation threshold to 5000 eV of the associated excited states have been derived by using the BE-scaling method. The resulted data can not only be used in plasma models but also serve as a benchmark for further theoretical calculations.
Observation of electron runaway in a tip-plane air gap under negative nanosecond pulse voltage by PIC/MCC simulation
Authors: Li Yutai , Fu Yangyang , Liu Zhigang , Li Handong , Wang Peng , Luo Haiyun , Zou Xiaobing , Wang Xinxin
Published: March 2022

The initial stage of the gas breakdown with the generation of runaway electrons was investigated using particle-in-cell/Monte Carlo collision simulations. The parameters of the solved problem are a 1 mm long atmospheric air gap between tip-plane electrodes applied with a nanosecond pulse voltage. The pulse is 5.2 ns in rising time (10%–90%), 10 ns in pulse width (FWHM) and 40 kV in amplitude. The cathode is a cone-shaped electrode, the tip of which is defined by the elliptic equation (the major axis is 4 mm and the minor axis is 1 mm), and the minimum radius of curvature is 0.125 mm. As it is found in the simulation that the development of the discharge channel from the cathode to the anode only takes about tens to hundreds of picoseconds, especially at high overvoltages with runaway electrons, it is assumed that the gap voltage applied in such a short time is nearly constant. Depending on the voltage at the breakdown, different behavior of the energetic electrons is observed. When the voltage is low, about 12 kV, energetic electrons are only produced in the tip cathode layer, where the electric field is the highest; no runaway electrons leading the discharge channel are observed. When the voltage is higher, about 15 kV, the energetic electrons begin to run away at the head of the discharge channel, where the electric field is high enough. When the voltage is even higher, the energetic electrons run away, even at the beginning of the discharge, and from the cathode to the anode. Pre-ionization of the gas ahead of the discharge channel by the runaway electrons is observed, which may play an important role in the fast breakdown of the gas under the nanosecond short pulse.
On the use of ultra-high resolution PIC methods to unveil microscale effects of plasma kinetic instabilities: electron trapping and release by electrostatic tidal effect
Authors: Schiesko L , Revel A , Minea T , Carbone E
Published: March 2022

Ultra-high resolution particle-in-cell coupled to Monte-Carlo collisions modelling unveils microscale instabilities in non-equilibrium plasmas fulfilling Penrose’s instability criterion. The spontaneous development of ion turbulence in the phase-space generated by charge exchange collisions leads to finite amplitude modulations of the local electric field. The latter are responsible for the trapping of low energy electrons and their transport from the plasma volume to the sheath vicinity. Electrostatic tidal effect occurring near the sheath is responsible for the release of the trapped electrons as a monochromatic bunch, accelerated back towards the source. This instability provides an additional theoretical ground for the anomalous enrichment of low-energy electrons observed by Langmuir probes in similar conditions. The present results demonstrate that marginally fulfilling PIC criteria is insufficient to study the microscale instabilities effects on the electrons dynamics in non-equilibrium low temperature plasmas.
Collisionless magnetized sheath resonance heating induced by a transverse magnetic field in low-pressure capacitive rf discharges
Authors: Sun Jing-Yu , Zhang Quan-Zhi , Schulze Julian , Wang You-Nian
Published: March 2022

The mechanism of resonance heating between the gyrating electrons and the oscillating sheath induced by a small transverse magnetic field in low-pressure capacitively coupled plasmas is investigated. The gyrating electrons will coherently collide with the expanding sheath if the electron gyro-frequency coincides with half the driving frequency. These electrons will gain substantial energy from collision-less heating, which strongly enhances the electron power absorption and the plasma density at a constant driving voltage. The electron kinetics is revealed at resonant conditions by particle simulations. Our numerical results demonstrate that the relation between the magnetic field and the driving frequency determines this resonance effect. Besides, it is found that the operating pressure, electrode gap, and driving voltage all strongly affect this electron resonance mechanism. The resonance effect is more pronounced at the conditions of low pressure, large gap, and high voltage.
Wave propagation and absorption in a helicon plasma thruster and its plume
Authors: Jiménez Pedro , Merino Mario , Ahedo Eduardo
Published: March 2022

A two-dimensional, full-wave, frequency domain, cold plasma model is used to study electromagnetic power propagation and absorption in a helicon plasma thruster, including its far plume region and surrounding space. Results show that a fraction of power is absorbed in the plume region, and that the power deposition in the source is essentially unperturbed by the simulation domain size, the presence of metallic obstacles, or the plasma density in the environment. An electron–cyclotron resonance (ECR) surface always exists downstream that effectively prevents radiation to the space beyond along the plume. In the presence of an overdense environmental plasma, like the one expected in a vacuum chamber, fields are fully evanescent beyond this transition, and vacuum chamber boundary conditions affect but little the wavefields before this surface. In the absence of an environmental plasma, a double wave regime transition exists at the interface between the plasma and vacuum that hinders accurate numerical simulation in the plume region.
Broadband plasmonic absorption enhancement of perovskite solar cells with embedded Au@SiO2@graphene core–shell nanoparticles
Authors: Talebi Hamideh , Emami Farzin
Published: March 2022

Although perovskite solar cells have shown outstanding photovoltaic performance, there are still various obstacles that limit their performance and that remain as significant challenges. Weak optical absorption rate in the infrared region is a significant drawback for this kind of solar cell. In this paper, Au@SiO2@Graphene nanoparticles (NPs) as nano-photonic inclusions in the perovskite layer are proposed and investigated theoretically. Unlike conventional nanoparticles, these NPs exhibit strong, multiple plasmon resonances at low energies. The effect of geometrical parameters, periodicity, and the location of the Au@SiO2@Graphene NPs in the perovskite layer upon the performance of the PSCs are investigated. Under improved conditions, an absorption enhancement of 32% is obtained compared to pristine devices. Also, the result attained from coupled optical-electrical simulation of the improved device demonstrated 20.05% power conversion efficiency. These improvements have been achieved due to the plasmonic near-field enhancement effects of Au@SiO2@Graphene nanoparticles along with increased light-scattering from these NPs.
Interplay of charge density waves, disorder, and superconductivity in 2H-TaSe2 elucidated by NMR
Authors: Baek Seung-Ho , Sur Yeahan , Kim Kee Hoon , Vojta Matthias , Büchner Bernd
Published: March 2022

Single crystals of pristine and 6% Pd-intercalated 2H‐TaSe2 have been studied by means of 77Se nuclear magnetic resonance. The temperature dependence of the 77Se spectrum, with an unexpected line narrowing upon Pd intercalation, unravels the presence of correlated local lattice distortions far above the transition temperature of the charge density wave (CDW) order, thereby supporting a strong-coupling CDW mechanism in 2H‐TaSe2. While, the Knight shift data suggest that the incommensurate CDW transition involves a partial Fermi surface gap opening. As for spin dynamics, the 77Se spin-lattice relaxation rate

T

1

−
1

as a function of temperature shows that a pseudogap behavior dominates the low-energy spin excitations even within the CDW phase, and gets stronger along with superconductivity in the Pd-6% sample. We discuss that CDW fluctuations may be responsible for the pseudogap as well as superconductivity, although the two phenomena are unlikely to be directly linked each other.
Gravitational wave background from mergers of large primordial black holes
Authors: Deng Heling
Published: March 2022

The Peters formula, which tells how the coalescence time of a binary
system emitting gravitational radiation is determined by the initial size
and shape of the elliptic orbit, is often used
in estimating the merger rate of primordial black holes and the gravitational wave background from the mergers. Valid as it is in some interesting
scenarios, such as the analysis of the LIGO-Virgo events,
the Peters formula fails to describe the coalescence time if the orbital period of the binary exceeds
the value given by the formula. This could underestimate the event rate
of mergers that occur before the cosmic time t ∼ 1013 s.
As a result, the energy density spectrum of the gravitational wave background could develop a peak, which is from mergers occurring at either t ∼ 1013 s (for black holes with mass M ≳ 108
M
⊙) or t ∼ 1026(M/M
⊙)-5/3 s (for 105
M
⊙ ≲ M ≲ 108
M
⊙). This
can be used to constrain the fraction of dark matter in
primordial black holes (denoted by f) if potential probes
(such as SKA and U-DECIGO) do not discover such a background,
with the result f ≲ 10-6–10-4 for the mass range 10– 109
M
⊙. We then consider the effect of mass accretion onto primordial black holes at redshift z ∼ 10, and find that the merger rate could drop significantly at low redshifts. The spectrum of the gravitational wave background thus gets suppressed at the high-frequency end. This feature might be captured by future detectors such as ET and CE for initial mass M = 𝒪(10–100) M
⊙ with f ≳ 10-4.
New scenario of QCD axion clump formation. Part I. Linear analysis
Authors: Kitajima Naoya , Kogai Kazuhiro , Urakawa Yuko
Published: March 2022

The QCD axion acquires the potential through the non-perturbative effect of the QCD matters around the QCD phase transition. During this period, the direct interaction between the axion and the QCD matters sets in.
Focusing on the impact of this direct interaction, we propose two scenarios where the fluctuation of the axion can rapidly grow, potentially leading to the formation of axion miniclusters even if the Peccei-Quinn (PQ) symmetry was already broken during inflation. The first scenario assumes that the primordial curvature perturbation at the horizon scale during the QCD epoch was significantly enhanced and the second one assumes that the initial misalignment was tuned around the hilltop of the potential.
Fast prediction of aerodynamic noise induced by the flow around a cylinder based on deep neural network
Authors: Meng Hai-Yang , Xu Zi-Xiang , Yang Jing , Liang Bin , Cheng Jian-Chun
Published: March 2022

Accurate and fast prediction of aerodynamic noise has always been a research hotspot in fluid mechanics and aeroacoustics. The conventional prediction methods based on numerical simulation often demand huge computational resources, which are difficult to balance between accuracy and efficiency. Here, we present a data-driven deep neural network (DNN) method to realize fast aerodynamic noise prediction while maintaining accuracy. The proposed deep learning method can predict the spatial distributions of aerodynamic noise information under different working conditions. Based on the large eddy simulation turbulence model and the Ffowcs Williams–Hawkings acoustic analogy theory, a dataset composed of 1216 samples is established. With reference to the deep learning method, a DNN framework is proposed to map the relationship between spatial coordinates, inlet velocity and overall sound pressure level. The root-mean-square-errors of prediction are below 0.82 dB in the test dataset, and the directivity of aerodynamic noise predicted by the DNN framework are basically consistent with the numerical simulation. This work paves a novel way for fast prediction of aerodynamic noise with high accuracy and has application potential in acoustic field prediction.
Testing the Empirical Relationship between Forbush Decreases and Cosmic Ray Diurnal Anisotropy
Authors: Adejoh Alhassan Jibrin , Okike Ogbonnaya , Ejikeme Chukwude Augustine
Published: March 2022

The abrupt aperiodic modulation of cosmic ray (CR) flux intensity, often referred to as Forbush decrease (FD), plays a significant role in our understanding of the Sun–Earth electrodynamics. Accurate and precise determinations of FD magnitude and timing are among the intractable problems in FD-based analysis. FD identification is complicated by CR diurnal anisotropy. CR anisotropy can increase or reduce the number and amplitude of FDs. It is therefore important to remove its contributions from CR raw data before FD identification. Recently, an attempt was made, using a combination of the Fourier transform technique and FD-location machine, to address this. Thus, two FD catalogs and amplitude diurnal variation (ADV) were calculated from filtered (FD1 and ADV) and raw (FD2) CR data. In the current work, we test the empirical relationship between FD1, FD2, ADV and solar-geophysical characteristics. Our analysis shows that two types of magnetic fields - interplanetary and geomagnetic (Dst) - govern the evolution of CR flux intensity reductions.
Thermodynamic effects in a gas modulated Invar-based dual Fabry–Pérot cavity refractometer
Authors: Rubin T , Silander I , Zakrisson J , Hao M , Forssén C , Asbahr P , Bernien M , Kussicke A , Liu K , Zelan M , Axner O
Published: March 2022

By measuring the refractivity and the temperature of a gas, its pressure can be assessed from fundamental principles. The highest performing instruments are based on Fabry–Perot cavities (FPC). Gas modulation refractometry (GAMOR) is a methodology that has the ability to reduce the influence of disturbances to such an extent that high-precision (sub-parts-per-million) assessments of pressure can be made by the use of FPCs of Invar. To allow for high accuracy assessments, it is of importance to assess the uncertainty contribution from the thermodynamic effects that are associated with the gas filling and emptying of the cavity (pV-work). This paper presents a detailed scrutiny of the influence of the gas exchange process on the assessment of gas temperature on an Invar-based dual-FPC (DFPC) instrumentation. It is shown that by virtue of a combination of a number of carefully selected design entities (a small cavity volume with a bore radius of 3 mm, a spacer material with high heat capacitance, large thermal conductivity, and no regions that are connected with low thermal conductance, i.e. no heat islands, and a continuous assessment of temperature of the cavity spacer) the system is not significantly affected by pV-work. Simulations show that 10 s after the filling all temperature gradients in the system are well into the sub-mK range. Experiments support that refractivity assessments initiated after 40 s are not significantly affected by the pV-work. The analysis given in this work indicates that an upper limit for the influence of pV-work on the Invar-based DFPC system using 100 s long gas modulation cycles is 0.5 mK/100 kPa (or 1.8 ppm/100 kPa). Consequently, thermodynamic effects will not be a limiting factor when the Invar-based DFPC GAMOR system is used for assessments of pressure or as a primary pressure standard up to atmospheric pressures.
Unusual superconductivity in the topological nodal-line semimetal candidate Sn
x
NbSe2-δ
Authors: Munir Riffat , Hasan Siddiquee K A M , Dissanayake Charuni , Kumarasinghe Kapila , Hu Xinzhe , Takano Yasumasa , Choi Eun Sang , Nakajima Yasuyuki
Published: March 2022

We report the superconductivity of the topological nodal-line semimetal candidate Sn
x
NbSe2-δ
with a noncentrosymmetric crystal structure. The superconducting transition temperature T
c of Sn
x
NbSe2-δ
drastically varies with the Sn concentration x and the Se deficiency δ, and reaches 12 K, relatively higher than those of known topological superconductors. The upper critical field of this compound shows unusual temperature dependence, inconsistent with the WHH theory for conventional type-II superconductors. In a low-Tc sample, the zero-temperature limit of the upper critical field parallel to the ab plane exceeds the Pauli paramagnetic limit estimated from the simple BCS weak coupling model by a factor of ∼ 2, suggestive of unusual superconductivity stabilized in Sn
x
NbSe2-δ
. Together with the robust superconductivity against disorder, these observations indicate that Sn
x
NbSe2-δ
is a promising candidate to explore topological superconductivity.
Revisiting Anderson-Higgs mechanism: application of Lieb-Schultz-Mattis theorem
Authors: Tada Yasuhiro
Published: March 2022

We consider an electron model of superconductivity on a three-dimensional lattice where there are on-site attractive Hubbard interaction and long-range repulsive Coulomb interaction. It is claimed that fully gapped s-wave superconductivity within this model, if present, exhibits spontaneous translation symmetry breaking possibly related to a charge order. Our discussions are based on an application of the Lieb-Schultz-Mattis theorem under some physical assumptions. The inconsistency between the proposed supersolid and experiments can impose some constraints on a reasonable choice of a theoretical model.
Field-Induced Quantum Spin Nematic Liquid Phase in the S=1 Antiferromagnetic Heisenberg Chain with Additional Interactions
Authors: Sakai Tôru , Nakano Hiroki , Furuchi Rito , Okamoto Kiyomi
Published: March 2022

The magnetization process of the S = 1 antiferromagnetic chain with the single-ion anisotropy D and the biquadratic interaction is investigated using the numerical diagonalization. Both interactions stabilize the 2-magnon Tomonaga-Luttinger liquid (TLL) phase in the magnetization process. Based on several excitation gaps calculated by the numerical diagonalization, some phase diagrams of the magnetization process are presented. These phase diagrams reveal that the spin nematic dominant TLL phase appears at higher magnetizations for sufficiently large negative D.
Magnetic and transport properties of a new ferromagnetic orthorhombic compound CePtAl2
Authors: Hayashi H , Matsuoka E , Sugawara H , Sakurai T , Ohta H
Published: March 2022

We have synthesized polycrystalline samples of CePtAl2 by arc melting method and examined their magnetic, transport and thermal properties by measuring the magnetization, the electrical resistivity, and the specific heat down to 0.4 K. As a result of these measurements, we found that CePtAl2 is a ferromagnetic Ce-based compound with the Curie-temperature Tc = 2.7 K.
Magnetic-field-tuned valence susceptibility in CeCo1−x
Fe
x
Si revealed by magnetostriction
Authors: Correa V F , Curci I , Sereni J G , Caroca Canales N , Geibel C
Published: March 2022

We report magnetoelastic studies in the CeCo1−x
Fe
x
Si alloys. Iron doping has a profound effect on the low temperature linear magnetostriction. At T = 2 K, the strength of the magnetostriction peaks at x = 0.23 where it reaches a value as large as

Δ
L

L

=
3
×

10

−
3

in an applied magnetic field B = 16 T. This Fe concentration corresponds to the critical one xc above which long-range antiferromagnetic order is no longer observed. The progressive increment of the hibridization between the Ce 4f orbital and the conduction band, as the magnetic order vanishes, gives rise to a sizeable valence susceptibility that can be finely tuned by the magnetic field explaining the large magnetostrictive effect around xc
. At higher x, the magnetostriction decreases, in agreement with a weaker valence susceptibility resulting from a stronger hibridization.
Modeling of Co impurity in Cu host using DFT+ED
Authors: Tchaplianka M , Shick A B , Kolorenč J
Published: March 2022

We investigate the electronic structure of a cobalt atom in a copper host using the density functional theory and the exact diagonalization of an Anderson impurity model. The spectral functions and spin moments at the impurity are calculated and are found to be close the ones calculated by DFT+QMC [1].
Coherent, time-correlated tunneling of density wave electrons
Authors: Miller John H , Suárez-Villagrán Martha Y
Published: March 2022

A growing body of evidence reveals that charge density wave (CDW) transport is a high-temperature cooperative quantum phenomenon. According to the time-correlated soliton tunneling (ST) model, quantum solitons, or electron-phonon correlates within the CDW condensate, act much like electrons tunneling through a Coulomb-blockade tunnel junction. Pair creation of charged fluidic soliton droplets is prevented by their electrostatic energy below a Coulomb-blockade threshold electric field. Above threshold, the quantum fluid flows in a periodic fashion, via a hybrid between Zener-like and coherent Josephson-like tunneling. We summarize the time-correlated ST model and compare model simulations with experiment. The ST model shows excellent agreement with coherent voltage oscillations, and with CDW current-voltage characteristics. Finally, we discuss implications for physics and potential applications.
Photoinduced Phase Transition in Two-Band model on Penrose Tiling
Authors: Inayoshi Ken , Murakami Yuta , Koga Akihisa
Published: March 2022

We study the effects of the photo irradiation on the band insulating state in the two-band Hubbard model on the Penrose tiling. Examining the time- and site-dependent physical quantities, we find that the excitionic state is dynamically induced with site-dependent order parameters. It is also clarified that, in the excitonic state induced by the photo irradiation, local oscillatory behavior appears in the electron number as well as in the order parameter, which should be characteristic of the quasiperiodic lattice.
Crystal-field excitations and quadrupolar fluctuations of 4f-electron systems studied by polarized light scattering
Authors: Ye M , Kung H H , Rosa P F S , Rosenberg E , Kim J , Xu X H , Bauer E D , Fisk Z , Fisher I R , Cheong S W , Blumberg G
Published: March 2022

We present Raman-scattering results for three materials, CeB6, TbInO3, and YbRu2Ge2, to illustrate the essential aspects of crystal-field (CF) excitations and quadrupolar fluctuations of 4f-electron systems. For CF excitations, we illustrate how the 4f orbits are split by spin-orbit coupling and CF potential by presenting spectra for inter- and intra-multiplet excitations over a large energy range. We discuss identification of the CF ground state and establishment of low-energy CF level scheme from the symmetry and energy of measured CF excitations. In addition, we demonstrate that the CF linewidth is a sensitive probe of electron correlation by virtue of self-energy effect. For quadrupolar fluctuations, we discuss both ferroquadrupolar (FQ) and antiferroquadrupolar (AFQ) cases. Long-wavelength quadrupolar fluctuations of the same symmetry as the FQ order parameter persists well above the transition temperature, from which the strength of electronic intersite quadrupolar interaction can be evaluated. The tendency towards AFQ ordering induces ferromagnetic correlation between neighboring 4f-ion sites, leading to long-wavelength magnetic fluctuations.
CeNi4Cr compound and its thermodynamic properties
Authors: Zapotoková Mariana , Reiffers Marián
Published: March 2022

CeNi5 as a mother compound is well known as a Stoner enhanced paramagnet characterized by the spin fluctuation contribution on its transport properties. Previous work on CeNi4Cr compound showed typical features of mixed valence systems with indication of tendency to heavy fermion behavior [1]. The theoretically predicted phase transition into antiferromagnetic order wasn’t observed down to 2 K. In this work we present the effect of spin fluctuations of the CeNi4Cr compound focused on its thermodynamic properties
Extremely High magnetoresistance and quantum Oscillation study of WTe2 Weyl Semimetal
Authors: Singh Abhishek , Sasmal Souvik , Iyer Kartik K , Thamizhavel A , Maiti Kalobaran
Published: March 2022

Single crystals of WTe2 have been prepared using the flux method. Analysis of the x-ray diffraction pattern shows the pure phase of the sample. Temperature dependent resistivity indicates the metallic nature of the sample. The residual resistance ratio of the sample has been found very high providing further evidence of the good quality of the crystals. Extremely high magnetoresistance has been observed in the sample. Quantum oscillations have been seen at high field. Fast Fourier transformation of the quantum oscillations shows nearly the same size of the electron and hole pocket in the sample.
Mössbauer effect study of a polycrystalline Fe1+xCr2-xO4 spinel grown by solid-state synthesis
Authors: Cherosov M A , Zinnatullin A L , Batulin R G , Kiiamov A G , Yusupov R V , Taurskii D A
Published: March 2022

Polycrystalline FeCr2O4 samples have been synthesized by the solid-state reaction method and studied with X-ray diffraction and Mössbauer spectroscopy. Rietveld refinement of X-ray diffraction pattern has been performed; obtained unit cell parameters are in a good agreement with ones in the literature. Mössbauer spectra were measured at room temperature and reveal by two components originating from the A and B sites of the spinel structure occupied by iron ions.
The surface tension at the metal-insulator phase transition in the magnetic field
Authors: Dubovskii L.B.
Published: March 2022

Any metal-insulator transition in a crystalline matter must be the transition from a situation in which the electronic bands overlap to that when they do not [1]. On the basis of the phenomenological theory [2], various singularities are considered in the magnetic field for the surface tension at the metal-insulator contact. The surface tension displays also the quantum magnetic oscillations at low temperatures [3]. The consideration is applied to the Mott insulator in the magnetic field.
Adiabatic specific heat measurement at very low temperatures using GM refrigerator
Authors: Nishioka Takashi , Moriyama Kazuaki , Okazaki Takuto , Miyamoto Satoru , Kado Tsuneo
Published: March 2022

We have developed an adiabatic specific heat measurementt using a 4 K GM refrigerator system that can measure down to 1.3 K with exactly the same accuracy as liquid helium environmen. The cryogenic environment can be obtained by liquefying about 20 L of helium gas at room temperature into a 1 K pot by a cascade method and evacuating it with a rotary pump. The 1 K pot temperature reaches 1.2 K. The specific heat measurement probe is mounted on the 1 K pot and is covered with three radiation shields, and the helium liquefied in the 1 K pot is maintained for about 70 minutes after the refrigerator is stopped, and the 1 K pot temperature maintains below 1.5 K. In this state, the specific heat from 1.3 K to 10 K can be measured. By tightly fixing the adenda to the support (base), temperature fluctuations due to mechanical vibration of the refrigerator can be greatly suppressed, and above 2.5 K, specific heat measurement with almost the same accuracy as when the refrigerator is stopped can be performed. By combining these two types of measurements, we can measure the specific heat with exactly the same accuracy as in a liquid helium environment.
First measurements on the Timespot1 ASIC: a fast-timing, high-rate pixel-matrix front-end
Authors: Piccolo L. , Cadeddu S. , Frontini L. , Lai A. , Liberali V. , Rivetti A. , Stabile A.
Published: March 2022

This work presents the first measurements performed on the Timespot1 ASIC. As the second prototype developed for the TimeSPOT project, the ASIC features a 32 × 32 channels hybrid-pixel matrix. Targeted to space-time tracking applications in High Energy Physics experiments, the system aims to achieve a time resolution of 30 ps or better at a maximum event rate of 3 MHz/channel with a data driven interface. Power consumption can be programmed to range between 1.2 W/cm2 and 2.6 W/cm2. The presented results include a description of the ASIC operation and a first characterization of its performance in terms of time resolution.
EXFOR-NSR PDF database: a system for nuclear knowledge preservation and data curation
Authors: Zerkin V.V. , Pritychenko B. , Totans J. , Vrapcenjak L. , Rodionov A. , Shulyak G.I.
Published: March 2022

Current needs of nuclear science and technology include complete, well-documented, and easily verifiable nuclear data. The complete data records require supporting nuclear bibliography, presently stored in dedicated libraries, in addition, to actual data. Experimental nuclear reaction data (EXFOR) and Nuclear Science References (NSR) databases contain compilations based on primary (journals) and secondary (conference proceedings, theses, preprints, etc.) publications, and data received from authors via private communications. The secondary library materials and private communications often represent a bottleneck for nuclear data verification, compilation, evaluation, and dissemination activities. To address this issue, bibliographic materials were scanned into PDF (Portable Document Format) files and uploaded in a relational database.

The traditional scope of nuclear databases that includes meta-data and numbers derived from data in specialized formats was broadened to accommodate the large volumes of original nuclear data publications. The complete PDF publication files were stored in a relational database as Binary Large OBjects (BLOB). This unique collection of nuclear data compilations and supporting publications generate many opportunities for machine learning applications.

The Web interfaces for authorized and public access to the EXFOR-NSR nuclear publications database were implemented at the U.S. National Nuclear Data Center, https://www.nndc.bnl.gov/ and IAEA Nuclear Data Section, https://www-nds.iaea.org/. The current system is complementary to major nuclear libraries and narrowly focused on nuclear data compilation and evaluation procedures. The contents of the PDF database, details of implementation, and Web interface are described. New capabilities for data curation, knowledge preservation, worldwide dissemination, and natural language processing (NLP) applications are given.
Spatiotemporal heterogeneities in water and land appropriations related to food losses and waste in China
Authors: Li Meng , Zhuo La , Liu Yilin , Yan Chenjian , Wu Pute
Published: March 2022

Fast-growing food losses and waste (FLW) have caused major environmental issues, yet little is known about the role of trade in the inefficient resource consumption related to FLW. In this study, we estimated the inter-annual water footprints (WFs) and land footprints (LFs) related to FLW in consideration of associated inter-provincial virtual water (VW) and virtual land (VL) flows within China from 2000 to 2017. Additionally, differences between eating at home and out in rural and urban regions were distinguished. The FLW-related WF and LF showed 1.5- and 1.2-fold increasing trends, respectively, over the study period. Eating at home in rural regions caused the most FLW and associated water and land appropriations. Both FLW-related gross inter-provincial VW and VL flows increased by 99% and 22% during the study period, respectively, and inter-provincial VW and VL flows in corresponding FLW-related WF and LF differed significantly. In addition, food losses were found to cause more inefficient resource consumption than food waste. This analysis shows that the substantial role of FLW in shaping the intra-national food-related VW and VL networks, and that the policies for FLW diminution at the food supply chain stage are as important as those at the consumption stage.
Infrared cavity ring-down spectroscopy for detecting non-small cell lung cancer in exhaled breath
Authors: Larracy Robyn , Phinyomark Angkoon , Scheme Erik
Published: March 2022

Early diagnosis of lung cancer greatly improves the likelihood of survival and remission, but limitations in existing technologies like low-dose computed tomography have prevented the implementation of widespread screening programs. Breath-based solutions that seek disease biomarkers in exhaled volatile organic compound (VOC) profiles show promise as affordable, accessible and non-invasive alternatives to traditional imaging. In this pilot work, we present a lung cancer detection framework using cavity ring-down spectroscopy (CRDS), an effective and practical laser absorption spectroscopy technique that has the ability to advance breath screening into clinical reality. The main aims of this work were to (1) test the utility of infrared CRDS breath profiles for discriminating non-small cell lung cancer (NSCLC) patients from controls, (2) compare models with VOCs as predictors to those with patterns from the CRDS spectra (breathprints) as predictors, and (3) present a robust approach for identifying relevant disease biomarkers. First, based on a proposed learning curve technique that estimated the limits of a model’s performance at multiple sample sizes (10–158), the CRDS-based models developed in this work were found to achieve classification performance comparable or superior to like mass spectroscopy and sensor-based systems. Second, using 158 collected samples (62 NSCLC subjects and 96 controls), the accuracy range for the VOC-based model was 65.19%–85.44% (51.61%–66.13% sensitivity and 73.96%–97.92% specificity), depending on the employed cross-validation technique. The model based on breathprint predictors generally performed better, with accuracy ranging from 71.52%–86.08% (58.06%–82.26% sensitivity and 80.21%–88.54% specificity). Lastly, using a protocol based on consensus feature selection, three VOCs (isopropanol, dimethyl sulfide, and butyric acid) and two breathprint features (from a local binary pattern transformation of the spectra) were identified as possible NSCLC biomarkers. This research demonstrates the potential of infrared CRDS breath profiles and the developed early-stage classification techniques for lung cancer biomarker detection and screening.
2D Cu2−

x
Se@graphene multifunctional interlayer boosting polysulfide rapid conversion and uniform Li2S nucleation for high performance Li–S batteries
Authors: Yuan Meng , Shi Haodong , Dong Cong , Zheng Shuanghao , Wang Kai , Wang Shaoxu , Wu Zhong-Shuai
Published: March 2022

Some vital challenges are main obstacles for further development of lithium–sulfur (Li–S) batteries such as low capacity and poor cycle stability resulted from polysulfide shuttling behavior, the physical/chemical entrapment is regarded as an effective method to inhibit and catalyze polysulfides. Herein we design a cross-linked framework of reduced graphene oxide anchored with Cu2−x
Se nanoparticles (Cu2−x
Se@rGO) by building an electrolyte/Cu2−x
Se/graphene triple-phase interface to be a high-efficiency electrocatalyst for Li–S batteries. Importantly, this three-dimensional conductive network possesses a large specific surface area with high ion transport capability, meanwhile providing strong physical constraint for efficient adsorption of soluble polysulfides. Further, this triple-phase catalytic interface provides strong chemical adsorption and abundant Cu2−x
Se nanoparticle sulfiphilic active sites, effectively inhibiting the dissolution of polysulfides and guaranteeing the efficient polysulfide adsorption catalysis as well as rapidly uniform Li2S nucleation. Consequently, with the Cu2−x
Se@rGO separator, a lower capacity decay rate about 0.059% per cycle after 500 cycles at 2 C is obtained. What’s more, with a higher areal sulfur loading of 3.0 mg cm−2, the capacity is still maintained at 805 mAh g−1 over 100 cycles. Therefore, this work will open new avenue to construct 2D transition metal selenide for superior performance Li–S batteries.