bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrical breakdown strength enhancement in aluminum scandium nitride through a compositionally modulated periodic multilayer structure
Authors: Zheng Jeffrey X. , Wang Dixiong , Musavigharavi Pariasadat , Fiagbenu Merrilyn Mercy Adzo , Jariwala Deep , Stach Eric A. , Olsson Roy H.
Published: October 2021

In this study, we report the effects of a multilayer architecture on the electrical breakdown strengths and ferroelectric characteristics of 45 nm thick aluminum scandium nitride (AlScN) films. Multilayered films (three-layer, five-layer, and seven-layer) are deposited via sequential deposition of Al0.72Sc0.28N and Al0.64Sc0.36N while maintaining constant volume ratios in all three samples. The effect of the increased number of interfaces is compared to 45 nm single layer Al0.72Sc0.28N and single layer Al0.64Sc0.36N films. The Weibull analysis shows an increase in the characteristic breakdown field from 5.99 and 5.86 MV/cm for single layer Al0.72Sc0.28N and Al0.64Sc0.36N to as high as 7.20 MV/cm in the seven-layered sample. The breakdown field to coercive field (EBD/Ec) ratios also increase from 1.37 and 1.26 in single layer Al0.72Sc0.28N and Al0.64Sc0.36N to up to 1.44 in the seven-layered sample with no significant change in remanent polarization. The enhancement of the characteristic breakdown field can be understood as the propagation of the electrical tree being deflected by multilayer interfaces and/or being slowed by the relative compressive stress in the alternating layers.
An investigation of particles effects on wall-normal velocity fluctuations in sand-laden atmospheric surface layer flows
Authors: Liu Hongyou , He Xibo , Zheng Xiaojing
Published: October 2021

Based on the high-quality observational data in the Qingtu Lake Observation Array (QLOA), the difference in the energy distribution, the scale of the coherent structures, and the amplitude modulation effect of the wall-normal velocity fluctuations between particle-free and particle-laden flow in the atmospheric surface layer are analyzed. The results show that the presence of particles enhanced the wall-normal turbulence intensity, especially the increase at the top of the logarithmic region is more significant though the particle mass loading decreases with the wall-normal distance. A further insight indicates that the increase in the length scale of the wall-normal fluctuating velocity coherent structure by particles is more significant further from the wall, which is supported by the premultiplied energy spectra and the two-point correlation. This leads to a drastic increase in kinetic energy of the large-scale coherent structures by the particle away from the wall and thus results in increased amplitude modulation effects of large-scale wall-normal velocity fluctuations onto small-scales.
Development and characterization of high-repetition-rate sources for supersonic beams of fluorine radicals
Authors: Straňák Patrik , Ploenes Ludger , Hofsäss Simon , Dulitz Katrin , Stienkemeier Frank , Willitsch Stefan
Published: October 2021

We present and compare two high-pressure, high-repetition-rate electric-discharge sources for the generation of supersonic beams of fluorine radicals. The sources are based on dielectric-barrier-discharge (DBD) and plate-discharge units attached to a pulsed solenoid valve. The corrosion-resistant discharge sources were operated with fluorine gas seeded in helium up to backing pressures as high as 30 bars. We employed a (3 + 1) resonance-enhanced multiphoton ionization combined with velocity-map imaging for the optimization, characterization, and comparison of the fluorine beams. Additionally, universal femtosecond-laser-ionization detection was used for the characterization of the discharge sources at experimental repetition rates up to 200 Hz. Our results show that the plate discharge is more efficient in F2 dissociation than the DBD by a factor between 8 and 9, whereas the DBD produces internally colder fluorine radicals.
Millimeter-wave electromagnetic monitoring for liquid metal droplet-on-demand printing
Authors: Chang T. , Mukherjee S. , Watkins N. N. , Benavidez E. , Gilmore A. M. , Pascall A. J. , Stobbe D. M.
Published: October 2021

As new printing approaches emerge, in situ diagnostics to monitor the print quality in real-time become essential for long-term monitoring and feedback control. In this article, we present a millimeter-wave electromagnetic monitoring approach for liquid metal droplet-on-demand printing to support the high-speed and real-time evaluation of droplet ejection. An open-ended rectangular waveguide is placed perpendicular to a jetted droplet stream and operated at a continuous-wave frequency of 40 GHz. Liquid metal droplets with diameters as low as 1.2 mm are characterized, and droplet jetting events on the order of 500 μm are detected at ejection rates up to 80 Hz. The measured results demonstrate that trends at the macro-level (large-scale print variation and anomalies at the nozzle tip) as well as micro-level (droplet size, position, and dynamics) can be detected using this technique.
Decorrelation of internal quantum efficiency and lasing threshold in AlGaN-based separate confinement heterostructures for UV emission
Authors: Cuesta Sergi , Denaix Lou , Dang Le Si , Monroy Eva
Published: October 2021

In this paper, we study the internal quantum efficiency and lasing threshold of AlGaN/GaN separate confinement heterostructures designed for ultraviolet laser emission. We discuss the effect of carrier localization and carrier diffusion on the optical performance. The implementation of graded index separate confinement heterostructures results in an improved carrier collection at the multi-quantum well, which facilitates population inversion and reduces the lasing threshold. However, this improvement is not correlated with the internal quantum efficiency of the spontaneous emission. We show that carrier localization at alloy inhomogeneities results in an enhancement of the radiative efficiency but does not reduce the laser threshold, which is more sensitive to the carrier injection efficiency.
Experimental determination of the interaction potential between a helium atom and the interior surface of a C60 fullerene molecule
Authors: Bacanu George Razvan , Jafari Tanzeeha , Aouane Mohamed , Rantaharju Jyrki , Walkey Mark , Hoffman Gabriela , Shugai Anna , Nagel Urmas , Jiménez-Ruiz Monica , Horsewill Anthony J. , Rols Stéphane , Rõõm Toomas , Whitby Richard J. , Levitt Malcolm H.
Published: October 2021

The interactions between atoms and molecules may be described by a potential energy function of the nuclear coordinates. Nonbonded interactions between neutral atoms or molecules are dominated by repulsive forces at a short range and attractive dispersion forces at a medium range. Experimental data on the detailed interaction potentials for nonbonded interatomic and intermolecular forces are scarce. Here, we use terahertz spectroscopy and inelastic neutron scattering to determine the potential energy function for the nonbonded interaction between single He atoms and encapsulating C60 fullerene cages in the helium endofullerenes 3He@C60 and 4He@C60, synthesized by molecular surgery techniques. The experimentally derived potential is compared to estimates from quantum chemistry calculations and from sums of empirical two-body potentials.
Liquid nucleation around charged particles in the vapor phase
Authors: Kroll Roni , Tsori Yoav
Published: October 2021

We theoretically investigate the nucleation of liquid droplets from vapor in the presence of a charged spherical particle. Due to field gradients, sufficiently close to the critical point of the vapor–gas system, the charge destabilizes the vapor phase and initiates a phase transition. The fluid’s free energy is described by the van der Waals expression augmented by electrostatic energy and a square-gradient term. We calculate the equilibrium density profile at arbitrary temperatures, particle charges, and vapor densities. In contrast to classical nucleation theory, here, both liquid and vapor phases are different from the bulk phases because they are spatially nonuniform. In addition, the theory applies to both sharp and diffuse interfaces and calculates the surface tension self-consistently. We find the composition profiles and integrate them to get the adsorption near the particle. We find that the adsorption changes discontinuously at a first-order phase transition line. This line becomes a second-order phase transition at high enough temperatures. We describe the transition point numerically and provide approximate analytical expressions for it. Similarly to prewetting, the adsorption diverges at the binodal phase boundary. We construct a phase diagram indicating changes in the binodal, spinodal, and critical temperature. It is shown that the field gradient enlarges the range of temperature and vapor density where liquid can nucleate.
The role of QED effects in transition energies of heavy-atom alkaline earth monofluoride molecules: A theoretical study of Ba+, BaF, RaF, and E120F
Authors: Skripnikov Leonid V. , Chubukov Dmitry V. , Shakhova Vera M.
Published: October 2021

Heavy-atom alkaline earth monofluoride molecules are considered as prospective systems to study spatial parity or spatial parity and time-reversal symmetry violating effects such as the nuclear anapole moment or the electron electric dipole moment. A comprehensive and highly accurate theoretical study of the electronic structure properties and transition energies in such systems can simplify the preparation and interpretation of the experiments. However, almost no attempts to calculate quantum electrodynamics (QED) effects’ contribution into characteristics of these neutral heavy-atom molecules have been performed. Recently, we have formulated and implemented such an approach to calculate QED contributions to transition energies of molecules [L. V. Skripnikov, J. Chem. Phys. 154, 201101 (2021)]. In this paper, we perform a benchmark theoretical study of the transition energies in the Ba+ cation and BaF molecule. The deviation of the calculated values from the experimental ones is of the order 10 cm−1 and is more than an order of magnitude better than the “chemical accuracy,” 350 cm−1. The achievement of such an agreement has been provided, in particular, by the inclusion of the QED effects. The latter appeared to be not less important than the high-order correlation effects beyond the coupled cluster with single, double, and perturbative triple cluster amplitude level. We compare the role of QED effects for transition energies with heavier molecules—RaF and E120F, where E120 is the superheavy Z = 120 homolog of Ra.
Comparison of thrusts imparted by a magnetron sputtering source operated in DC and high power impulse modes
Authors: Takahashi Kazunori , Miura Hidemasa
Published: October 2021

The thrusts induced by the 45-mm-diameter DC and high power impulse magnetron sputtering [DC magnetron sputtering (DCMS) and high power impulse magnetron sputtering (HiPIMS)] sources are assessed by using the pendulum thrust balance, where the instantaneous discharge power for the HiPIMS is two orders of magnitude larger than that for the DCMS. The temporally averaged power of the HiPIMS is chosen as 50–150 W, being similar to the DCMS, by adjusting the duty cycle. The thrust-to-power ratios of 9.1 and 3.7 mN/kW are obtained for the DCMS and HiPIMS, respectively, by ejecting the copper target material via sputtering. A comparison between the thrust and the deposition rate of the copper film on a substrate implies that the flux and the velocity of the ejected material for the DCMS are larger and lower than those for the HiPIMS, respectively.
Multi-state formulation of the frozen-density embedding quasi-diabatization approach
Authors: Eschenbach Patrick , Artiukhin Denis G. , Neugebauer Johannes
Published: October 2021

We present a multi-state implementation of the recently developed frozen-density embedding diabatization (FDE-diab) methodology [D. G. Artiukhin and J. Neugebauer, J. Chem. Phys. 148, 214104 (2018)] in the Serenity program. The new framework extends the original approach such that any number of charge-localized quasi-diabatic states can be coupled, giving an access to calculations of ground and excited state spin-density distributions as well as to excitation energies. We show that it is possible to obtain results similar to those from correlated wave function approaches such as the complete active space self-consistent field method at much lower computational effort. Additionally, we present a series of approximate computational schemes, which further decrease the overall computational cost and systematically converge to the full FDE-diab solution. The proposed methodology enables computational studies on spin-density distributions and related properties for large molecular systems of biochemical interest.
Biological soil quality and seasonal variation on enzyme activities under conservation agriculture-based rice–mustard system in the Indo-Gangetic Plains of India
Authors: Biswas Sunanda , Das T. K. , Bhattacharyya Ranjan , Das Shrila , Dwivedi B. S.
Published: October 2021

Context Biological quality of soil under rice-based cropping in Indo-Gangetic Plains of India is greatly influenced by different tillage and residue management practices. Aims The objectives of this study were to determine the effect of seasonal variation on enzyme activity and assessing biological soil quality (BSQ) under conservation agriculture (CA)-based rice–mustard cropping. Methods Soil samples were collected in the ninth year of a medium-term CA-based experiment in autumn, winter, spring and summer seasons from two soil depths (0–5 cm, 5–15 cm) and analysed for biological attributes (microbial biomass carbon, MBC; Walkley–Black carbon, WBC; total organic carbon, TOC), and enzyme activities (dehydrogenase, acid and alkaline phosphatase, and arylsulphatase). Key results A CA-based triple zero till (ZT) system with three crops residue treatments (ZT direct-seeded rice (DSR) with mungbean residue; ZT mustard (ZTM) with rice residue; and ZT summer mungbean (SMB) with mustard residue (∼ZTDSR–ZTM–ZTSMB (+R)) resulted in highest values of MBC, WBC and TOC at the 0–5 cm soil depth. Enzymes activities were highest during summer. Principal component analysis (PCA) and showed that arylsulphatase activity and TOC were sensitive indicators of BSQ. To validate soil quality indices (SQIs), regression analyses with rice equivalent yield (REY) of the rice–mustard system were done and better relationship observed with biological soil quality indices (BSQI) BSQIGMean (0.69–0.71) than BSQIPCA (0.65–0.66) based method. Conclusions Treatment with ZTDSR–ZTM–ZTSMB (+R) had the highest values of BSQI using GMean and PCA. Implications This CA-based triple ZT with residue practice [ZTDSR–ZTM–ZTSMB (+R)] is recommended for rice–mustard cropping for maintaining higher biological quality of soil in this region of India.
Combined solar power and storage as cost-competitive and grid-compatible supply for China’s future carbon-neutral electricity system
Authors: Lu Xi , Chen Shi , Nielsen Chris P. , Zhang Chongyu , Li Jiacong , Xu He , Wu Ye , Wang Shuxiao , Song Feng , Wei Chu , He Kebin , McElroy Michael B. , Hao Jiming
Published: October 2021

Significance

Solar photovoltaic power is gaining momentum as a solution to intertwined air pollution and climate challenges in China, driven by declining capital costs and increasing technical efficiencies. The dynamic spatial trajectory of cost-competitive and grid-compatible penetration potentials for solar power will be a critical determinant of the speed of energy system decarbonization in China. This study develops an integrated model to assess solar photovoltaic potentials and their cost competitiveness throughout 2020 to 2060 considering multiple spatiotemporal factors. We find that the cost competitiveness of solar power allows for pairing with storage capacity to supply 7.2 PWh of grid-compatible electricity, meeting 43.2% of China’s demand in 2060 at a price lower than 2.5 US cents/kWh.
Confederate monuments and the history of lynching in the American South: An empirical examination
Authors: Henderson Kyshia , Powers Samuel , Claibourn Michele , Brown-Iannuzzi Jazmin L. , Trawalter Sophie
Published: October 2021

Significance

The fight over Confederate monuments has fueled lawsuits, protests, counterprotests, arrests, even terrorism, as we painfully saw in August 2017 in Charlottesville, VA. The fight rests on a debate over whether these monuments represent racism (“hate”) or something ostensibly devoid of racism (“heritage,” “Southern pride”). Herein, we show that Confederate monuments are tied to a history of racial violence. Specifically, we find that the number of lynching victims in a county is a positive and significant predictor of Confederate memorializations in that county, even after controlling for relevant covariates. This finding provides concrete, quantitative, historically and geographically situated evidence consistent with the position that Confederate memorializations reflect a racist history, marred by intentions to terrorize and intimidate Black Americans.
A novel class of TMPRSS2 inhibitors potently block SARS-CoV-2 and MERS-CoV viral entry and protect human epithelial lung cells
Authors: Mahoney Matthew , Damalanka Vishnu C. , Tartell Michael A. , Chung Dong hee , Lourenço André Luiz , Pwee Dustin , Mayer Bridwell Anne E. , Hoffmann Markus , Voss Jorine , Karmakar Partha , Azouz Nurit P. , Klingler Andrea M. , Rothlauf Paul W. , Thompson Cassandra E. , Lee Melody , Klampfer Lidija , Stallings Christina L. , Rothenberg Marc E. , Pöhlmann Stefan , Whelan Sean P. J. , O’Donoghue Anthony J. , Craik Charles S. , Janetka James W.
Published: October 2021

Significance

MM3122 represents an advanced lead candidate for clinical development as a novel antiviral drug for COVID-19. In addition to being novel drugs, these selective TMRSS2 inhibitors can be used as valuable chemical probes to help elucidate mechanisms of viral pathogenesis. Since TMPRSS2 plays a key role as a viral protein processing protease in the pathogenesis of other coronaviruses (SARS-CoV, MERS-CoV) as well as influenza viruses, MM3122 and this class of TMPRSS2 inhibitors hold much promise as new drugs to not only treat SARS-CoV-2 infections but also potentially represent broad-spectrum antivirals.
Absorbed dose rate coefficients for 134Cs and 137Cs with steady-state distribution in the human body: S-coefficients revisited
Authors: Isaksson Mats , Tondel Martin , Wålinder Robert , Rääf Christopher
Published: October 2021

In the event of an accidental release of radioactive elements from a nuclear power plant, it has been shown that the radionuclides contributing the most to long-term exposure are 134Cs and 137Cs. In the case of nuclear power plant fallout, with subsequent intake of radionuclides through the food chain, the internal absorbed dose to target tissues from protracted intake of radionuclides needs to be estimated. Internal contamination from food consumption is not caused by a single intake event; hence, the committed equivalent dose, calculated by a dose coefficient or dose per content function, cannot be easily used to calculate the cumulative absorbed dose to relevant target tissues in the body. In this study, we calculated updated absorbed dose rate coefficients for 134Cs and 137Cs based on data from the International Commission on Radiological Protection (ICRP) on specific absorbed fractions. The absorbed dose rate coefficients are provided for male and female adult reference phantoms, respectively, assuming a steady-state distribution of Cs that we calculated from the ICRP biokinetic model for Cs. With these coefficients, the absorbed dose to the listed target tissues, separately and to the total body, are related to the number of nuclear transitions (time-integrated activity) in each listed source region. Our new absorbed dose rate coefficients are given for the complete set of target tissues and have not been presented before. They are also provided for aggregated categories of organs to facilitate epidemiological studies.
Phase-field crystal study on the influence of nanoscale intergranular structures on grain boundary segregation
Authors: Su Shasha , Tang Sai , Liang Chaoping , Ma Yunzhu , Liu Wensheng
Published: October 2021

Grain boundary (GB) segregation can substantially affect the performance of materials by greatly changing the chemical compositions of GB. It is well known that GB segregation is essentially attributed to the structural differences between the bulk of grain and GB. Nevertheless, we still lack a clear understanding about the correlation between nanoscale intergranular structures and solute segregation. In this work, by using the phase-field crystal model, we performed atomic scale simulations to investigate the segregation of Li atoms to symmetric ⟨110⟩ tilt GBs in binary Al–Li alloys. It was found that the amount of segregated solute increases proportionally to GB misorientation angle in the case of low-angle tilt GBs, and converges at high-angle tilt GBs, except some special GBs with coincidence-site lattice. This is analogous to the dependences of GB energy and density on the misorientation angle. The correlations among GB structure, misfit strain around GBs and solute segregation are quantified at atomic scale. In low-angle tilt GBs, Li atoms are segregated to the compress zone around the core of intergranular dislocations to release the misfit strain energy. In the general high-angle tilt GBs, since the GB structure and misfit strain energy is uniform, the segregated atoms distribute homogeneously along GB. Particularly, the regular arrangement of structural units in some low Σ GBs lead to very low misfit strain energy, and accordingly to a periodically distributed and very low amount of solute segregation.
Thermally propagated Al contacts on SiGe nanowires characterized by electron beam induced current in a scanning transmission electron microscope
Authors: Conlan Aidan P , Luong Minh Anh , Gentile Pascal , Moldovan Grigore , Den Hertog Martien I , Monroy Eva , Cooper David
Published: October 2021

Here, we use electron beam induced current (EBIC) in a scanning transmission electron microscope to characterize the structure and electronic properties of Al/SiGe and Al/Si-rich/SiGe axial nanowire heterostructures fabricated by thermal propagation of Al in a SiGe nanowire. The two heterostructures behave as Schottky contacts with different barrier heights. From the sign of the beam induced current collected at the contacts, the intrinsic semiconductor doping is determined to be n-type. Furthermore, we find that the silicon-rich double interface presents a lower barrier height than the atomically sharp SiGe/Al interface. With an applied bias, the Si-rich region delays the propagation of the depletion region and presents a reduced free carrier diffusion length with respect to the SiGe nanowire. This behaviour could be explained by a higher residual doping in the Si-rich area. These results demonstrate that scanning transmission electron microscopy EBIC is a powerful method for mapping and quantifying electric fields in micrometer- and nanometer-scale devices.
Optical and structural properties of europium doped Y–Al–O compounds grown by microwave driven hydrothermal technique
Authors: Cichocka Nikola , Kobyakov Serhiy , Kaszewski Jaroslaw , Reszka Anna , Minikayev Roman , Sobczak Kamil , Choinska Emilia , Kaminska Agata
Published: October 2021

Perovskites, garnets, monoclinic forms, and lately also oxyhydroxides doped with rare-earth ions have been drawn large attention due to their beneficial optical and photovoltaic properties. In this work, we have shown that several forms of crystals from Y–Al–O family can be synthesized using microwave driven hydrothermal technique using different pH and post-growth annealing at different temperatures. The structural and optical properties of these crystals were investigated as a function of hydrothermal crystallization conditions. For this purpose, x-ray diffraction, scanning electron microscopy, energy-dispersive x-ray spectroscopy, transmission electron microscopy, photoluminescence, and photoluminescence excitation studies were performed. All the structures have been doped with Eu3+ ions which are known as a local symmetry sensor because various symmetries generate different crystal fields and thus affect their luminescence spectra. The optical properties of the obtained nanoparticles in correlation with their structure and chemical composition are discussed.
Key designs of a short-bore and cryogen-free high temperature superconducting magnet system for 14 T whole-body MRI
Authors: Li Yi , Roell Stefan
Published: October 2021

A 14 T whole-body magnetic resonance imaging (MRI) magnet is designed with Bi2223 high temperature superconducting (HTS) wire. Owing to the large critical current and large critical tensile strength of the wire type HT-NX at ultra-high field, the magnet is optimized in a compact shape with length of 1.9 m and outer diameter of 1.3 m. It is in the form of stacked double pancakes (DPs) with total wire consumption of 455 km. The DPs with various inner and outer radii enable the electromagnetic design to obtain highly homogeneous field of 1.5 ppm over 400 mm diameter of spherical volume (DSV). Hoopstress by winding process, thermal contraction and Lorenz force is calculated and below the wire strength specification. Considerable reduction of screening current effect in MRI magnet application is proved by a calculation example. Field homogeneity as it is influenced by various systematic tolerances and random geometric tolerances is numerically estimated, for further design optimization and design of shimming system. Iron room for passive shielding with dimension of 5 × 5 × 10 m is found to be with wall thickness of around 30 cm to effectively contain the 5-Gauss field to the wall surface. Cooling strategy for cryogen-free technique is proposed and the magnet coils temperature is calculated as below 8 K based on the estimation of joint Ohmic heating power of 1.0 W. Quench protection adopts circuit subdivision and dumping resistors to restrict the maximum voltage below 1.9 kV. No-insulation technique for the quench protection is also discussed. Some other wire candidates like REBCO and Nb3Sn for development of such ultra-high field MRI magnets are commented.
Weak cosmic censorship conjecture in Kerr-Newman-(anti-)de Sitter black hole with charged scalar field
Authors: Gwak Bogeun
Published: October 2021

We investigate the weak cosmic censorship conjecture in extremal and near-extremal Kerr-Newman-(anti-)de Sitter black holes by the scattering of a massive scalar field with an electric charge. Under this scattering, the scalar field fluxes change the black hole state, as determined by the mass, angular momentum, and electric charge. The black hole may exceed its extremal condition because of these changes. However, we find that the black hole cannot be overcharged or overspun by the scattering. In particular, although the fluxes are closely associated with the asymptotic boundary conditions along the flat, anti-de Sitter, and de Sitter spacetimes, the weak cosmic censorship conjecture is valid for any scalar field boundary conditions. Moreover, the validity of the weak cosmic censorship conjecture is thermodynamically preferred for this scattering.
Mechanism of primordial black holes production and secondary gravitational waves in α-attractor Galileon inflationary scenario
Authors: Teimoori Zeinab , Rezazadeh Kazem , Rasheed Mariwan Ahmed , Karami Kayoomars
Published: October 2021

We study the process of the Primordial Black Holes (PBHs)
production in the novel framework, namely α-attractor
Galileon inflation (G-inflation) model. In our framework, we take
the Galileon function as
G(ϕ)=GI
(ϕ)(1+GII
(ϕ)), where the part
GI
(ϕ) is motivated from the α-attractor inflationary
scenario in its original non-canonical frame, and it ensures for the
model to be consistent with the Planck 2018 observations at the CMB
scales. The part GII
(ϕ) is invoked to enhance the curvature
perturbations at some smaller scales which in turn gives rise to
PBHs formation. By fine-tuning of the model parameters, we find
three parameter sets which successfully produce a sufficiently large
peak in the curvature power spectrum. We show that these parameter
sets produce PBHs with masses 𝒪(10)M
☉, 𝒪(10-5)M
☉, and 𝒪(10-13)M
☉ which can
explain the LIGO events, the ultrashort-timescale microlensing
events in OGLE data, and around 0.98% of the current Dark Matter
(DM) content of the universe, respectively. Additionally, we study
the secondary Gravitational Waves (GWs) in our setup and show that
our model anticipates the peak of their present fractional energy
density as ΩGW0
 ∼ 10-8 for all the three
parameter sets, but at different frequencies. These predictions can
be located well inside the sensitivity region of some GWs detectors,
and therefore the compatibility of our model can be assessed in
light of the future data. We further estimate the tilts of the
included GWs spectrum in the different ranges of frequency, and
confirm that spectrum follows the power-law relation ΩGW0
 ∼ fn
in those frequency bands.
A spin-less particle on a rotating curved surface in Minkowski space
Authors: Cheng Run , Wang Li , Zhao Hao , Luo Cui-Bai , Wang Yong-Long , Wang Jun
Published: October 2021

In Minkowski space



, we derive the effective Schrödinger equation describing a spin-less particle confined to a rotating curved surface



. Using the thin-layer quantization formalism to constrain the particle on



, we obtain the relativity-corrected geometric potential

V

g

′

, and a novel effective potential

V

˜

g

related to both the Gaussian curvature and the geodesic curvature of the rotating surface. The Coriolis effect and the centrifugal potential also appear in the equation. Subsequently, we apply the surface Schrödinger equation to a rotating cylinder, sphere and torus surfaces, in which we find that the interplays between the rotation and surface geometry can contribute to the energy spectrum based on the potentials they offer.
Polymorph selection of magnesium under different pressures: A simulation study
Authors: Liu Wei , Wu Boqiang , Tian Ze’an , Mo Yunfei , Xi Tingfei , Wan Zhiyi , Liu Rangsu , Liu Hairong
Published: October 2021

Molecular dynamics simulations were used to investigate the influence of pressure on the structural properties and dynamics of magnesium (Mg) during rapid solidification. The dynamics analysis revealed that, with an increase in pressure, the dynamics of Mg melt slowed down sharply and the dynamical heterogeneities increased, leading to a denser structure. Atom-level structural analysis using the cluster-type index method suggested that the predominant structure transformed from hexagonal closed-packed to face-centered cubic with increasing pressure from 0 GPa to 5 GPa, and then transformed to the A15 complex crystal structure as the pressure increased above 10 GPa. In addition, the nature of polymorph selection was investigated by analyzing the phonon dispersion of Mg under different pressures. These findings provide a novel insight into polymorphic transitions of Mg under pressure and guide the selection of Mg polymorphs for practical applications.
Debye-screening effect on electron-impact excitation of helium-like Al11+ and Fe24+ ions
Authors: Ma Yu-Long , Liu Ling , Xie Lu-You , Wu Yong , Zhang Deng-Hong , Dong Chen-Zhong , Qu Yi-Zhi , Wang Jian-Guo
Published: October 2021

Debye-screening effects on the electron-impact excitation (EIE) processes for the dipole-allowed transition 1s2
1 S → 1s2p 1P in He-like Al11+ and Fe24+ ions are investigated using the fully relativistic distorted-wave methods with the Debye–Hückel (DH) model potential. Debye-screening effects on the continuum-bound (CB) interaction and target ion are discussed, both of which result in reduction of EIE cross sections. This reduction due to screening on the CB interaction is dominant. The non-spherical and spherical DH potentials are adopted for considering the screening effect on the CB interaction. It is found that the spherical DH potential could significantly overestimate the influence of plasma screening on EIE cross sections for multielectron He-like ions.
Effect of dark energy models on the energy content of charged and rotating black holes
Authors: Liaqat Asia , Hussain Ibrar
Published: October 2021

The energy content of the charged-Kerr (CK) spacetime surrounded by dark energy (DE) is investigated using approximate Lie symmetry methods for the differential equations. For this, we consider three different DE scenarios: cosmological constant with an equation of state parameter

, quintessence DE with an equation of state parameter

, and a frustrated network of cosmic strings with an equation of state parameter

. To study the gravitational energy of the CK black hole surrounded by the DE, we explore the symmetries of the 2nd-order perturbed geodesic equations. It is noticed, for all the values of ω, the exact symmetries are recovered as 2nd-order approximate trivial symmetries. These trivial approximate symmetries give the rescaling of arc length parameter s in this spacetime which indicates that the energy in the underlying spacetime has to be rescaled by a factor that depends on the black hole parameters and the DE parameter. This rescaling factor is compared with the factor of the CK spacetime found in [Hussain et al. Gen. Relativ. Gravit. (2009)] and the effects of the DE on it are discussed. It is observed that for all the three values of the equation of state parameter ω, the effect of DE results in decreased energy content of the black hole spacetime, regardless of values of the charge Q, spin a and the DE parameter α. This reduction in the energy content due to the involvement of the DE favours the idea of mass reduction of black holes by accretion of DE given by [Babichev et al. Phys. Rev. Lett. (2004)].
An overview of magneto-inertial fusion on the Z machine at Sandia National Laboratories
Authors: Yager-Elorriaga D.A. , Gomez M.R. , Ruiz D.E. , Slutz S.A. , Harvey-Thompson A.J. , Jennings C.A. , Knapp P.F. , Schmit P.F. , Weis M.R. , Awe T.J. , Chandler G.A. , Mangan M. , Myers C.E. , Fein J.R. , Galloway B.R. , Geissel M. , Glinsky M.E. , Hansen S.B. , Harding E.C. , Lamppa D.C. , Lewis W.E. , Rambo P.K. , Robertson G.K. , Savage M.E. , Shipley G.A. , Smith I.C. , Schwarz J. , Ampleford D.J. , Beckwith K. , Peterson K.J. , Porter J.L. , Rochau G.A. , Sinars D.B.
Published: October 2021

We present an overview of the magneto-inertial fusion (MIF) concept Magnetized Liner Inertial Fusion (MagLIF) pursued at Sandia National Laboratories and review some of the most prominent results since the initial experiments in 2013. In MagLIF, a centimeter-scale beryllium tube or ‘liner’ is filled with a fusion fuel, axially pre-magnetized, laser pre-heated, and finally imploded using up to 20 MA from the Z machine. All of these elements are necessary to generate a thermonuclear plasma: laser preheating raises the initial temperature of the fuel, the electrical current implodes the liner and quasi-adiabatically compresses the fuel via the Lorentz force, and the axial magnetic field limits thermal conduction from the hot plasma to the cold liner walls during the implosion. MagLIF is the first MIF concept to demonstrate fusion relevant temperatures, significant fusion production (>1013 primary DD neutron yield), and magnetic trapping of charged fusion particles. On a 60 MA next-generation pulsed-power machine, two-dimensional simulations suggest that MagLIF has the potential to generate multi-MJ yields with significant self-heating, a long-term goal of the US Stockpile Stewardship Program. At currents exceeding 65 MA, the high gains required for fusion energy could be achievable.
RETRACTED: Design and Development of Temperature Measurement and Control System Based on Mcu under the Background of Internet of Things
Authors: Wang Yan
Published: October 2021

Internet of things technology is a new technology recently developed, it also belongs to an area of information technology, and its appearance makes it means more perfect and mature. At present, industrial automation is the trend of the development of the present era, and the single chip microcomputer is the core of industrial automation. It is the core system of process control, process monitoring and Mechatronics integrated control of industrial automation. With the rapid development of single chip microcomputer, especially the hardware of MCU. These changes have brought great changes to the development language of SCM software. The development of SCM control system to intelligent control gradually improves the development efficiency of the system, and also ensures the quality of products. In order to explore the application effect of Internet of things technology in the TMACS(temperature measurement and control system) design and development of single chip microcomputer, we choose h and G factories as experimental research objects, among which h factory applies Internet of things technology in its single chip microcomputer working system, and factory g still adopts conventional methods. From the experimental results, we can see that the accuracy of H plant is up to 95%, while the highest accuracy rate of plant G is only 75%, which is 20% lower than that of H plant.
Improving physical parameters estimation in the single-beam multiple-intensity reconstruction
Authors: Chen Xiaoyi , Duan Yaxuan , Da Zhengshang
Published: October 2021

The iterative phase retrieval based on phase diversity technologies can solve the stagnation problem of Gerchberg–Saxton algorithm which performs Fourier transform to iterate back and forth between the object and spectral planes with known constraints. However, the application of phase diversity technologies in iterative phase retrieval methods will bring in multiple physical parameters such as distances or wavelengths. The measured accuracy of these physical parameters will ultimately affect the accuracy of the iterative phase retrieval methods. In this paper, a physical parameters estimation method which has the advantages of high global convergence and local convergence is proposed to improve the accuracy of iterative phase retrieval methods. Meanwhile, this method is introduced in the single-beam multiple-intensity reconstruction (SBMIR), termed PE-SBMIR, and its performance is verified by simulations and experiments. By simulating multiple sets of distance parameters with errors, the retrieved accuracy using PE-SBMIR can be improved by 2–4 orders of magnitude compared with SBMIR. Experimental results show that whether it is an amplitude-type object or phase-type object, the accuracy using PE-SBMIR is significantly higher than using SBMIR. The physical parameters estimation method proposed in this paper may be adopted in other iterative phase retrieval methods using phase diversity technologies.
Numerical study of polarization evolution governed by linear birefringence, twist-induced circular birefringence and nonlinear birefringence in a single-mode optical fiber
Authors: Ibarra-Villalon H E , Pottiez O , Gómez-Vieyra A , Lauterio-Cruz J P , Bracamontes-Rodriguez Y E
Published: October 2021

This tutorial presents a numerical analysis of continuous wave and ultrashort pulse evolution through a twisted single-mode optical fiber, modeled by the nonlinear Schrödinger equation. In this model, the polarization evolutions of the continuous wave and the pulse profile are studied by the changes in ellipticity and ellipse rotation, which are driven by the inherent linear birefringence of the optical fiber, the induced nonlinear birefringence due to the centrosymmetric response of the fiber and the induced circular birefringence due to a uniform twist applied along the fiber. In particular, the role of each birefringence effect is studied in detail. As a result, it is pointed out that a large uniform twist rate allows viewing the optical fiber as an isotropic waveguide that preserves ellipticity. On the other hand, a saturable absorber mechanism based on a linear polarizer and the ellipse rotation in a twisted fiber, which introduces a nonlinear transmission characteristic that is part of the principles of operation of the mode-locked fiber lasers, is analyzed in order to illustrate the applicability of this numerical study.
The propagation dynamics and stability of an intense laser beam in a radial power-law plasma channel
Authors: HONG Xueren , ZHANG Desheng , GAO Jiming , TANG Rongan , GUO Peng , XUE Jukui
Published: October 2021

By containing ponderomotive self-channeling, the propagation behavior of an intense laser beam and the physical conditions are obtained theoretically in a radial power-law plasma channel. It is found that ponderomotive self-channeling results in the emergence of a solitary wave and catastrophic focusing, which apparently decreases the region for stable propagation in a parameter space of laser power and the ratio of the initial laser spot radius to the channel radius (RLC). Direct numerical simulation confirms the theory of constant propagation, periodic defocusing and focusing oscillations in the parameter space, and reveals a radial instability which prevents the formation of bright and dark solitary waves. The corresponding unstable critical curve is added in the parameter space numerically and the induced unstable region above the unstable critical curve covers that of catastrophic focusing, which shrinks the stable region for laser beams. For the expected constant propagation, the results reveal the need for a low RLC. Further study illustrates that the channel power-law exponent has an obvious effect on the final stable region and laser propagation, for example increasing this exponent can enlarge the stable region significantly, which is beneficial for guiding of the laser and increases the lowest RLC for constant propagation. Our results also show that the initial laser amplitude has an apparent influence on the propagation behavior.
Fighting over defense chemicals disrupts mating behavior
Authors: Paul Sarah Catherine , Müller Caroline
Published: October 2021

Studies on intraspecific contest behavior predominantly focus on contests between individuals of the same sex, however contest behavior is also expected to occur between individuals of the opposite sex including possible mates. Here we investigate potential trade-offs between mating and fighting behavior in the turnip sawfly (Athalia rosae). Adults of this species collect chemical defense compounds (clerodanoids) directly from plants but also indirectly by nibbling on conspecifics that have already obtained clerodanoids, a highly aggressive behavioral interaction. An A. rosae individual without clerodanoids may therefore be the potential mate or attacker of an individual of the opposite sex that has gained clerodanoids. To test the effect of clerodanoids on agonistic and mating behavior we paired females and males with or without clerodanoid access in a two-way factorial design. We show that asymmetrical clerodanoid acquisition between female-male pairs causes an increase in agonistic nibbling behavior, irrespective of sex, and moreover that conflict between individuals delays mating behavior. Our study highlights the importance of investigating agonistic intersex interactions, which can occur when adults are able to acquire valuable non-reproductive resources from a potential partner.
App-SpaM: phylogenetic placement of short reads without sequence alignment
Authors: Blanke Matthias , Morgenstern Burkhard
Published: October 2021

Motivation

Phylogenetic placement is the task of placing a query sequence of unknown taxonomic origin into a given phylogenetic tree of a set of reference sequences. A major field of application of such methods is, for example, the taxonomic identification of reads in metabarcoding or metagenomic studies. Several approaches to phylogenetic placement have been proposed in recent years. The most accurate of them requires a multiple sequence alignment of the references as input. However, calculating multiple alignments is not only time-consuming but also limits the applicability of these approaches.

Results

Herein, we propose Alignment-free phylogenetic placement algorithm based on Spaced-word Matches (App-SpaM), an efficient algorithm for the phylogenetic placement of short sequencing reads on a tree of a set of reference sequences. App-SpaM produces results of high quality that are on a par with the best available approaches to phylogenetic placement, while our software is two orders of magnitude faster than these existing methods. Our approach neither requires a multiple alignment of the reference sequences nor alignments of the queries to the references. This enables App-SpaM to perform phylogenetic placement on a broad variety of datasets.

Availability and implementation

The source code of App-SpaM is freely available on Github at https://github.com/matthiasblanke/App-SpaM together with detailed instructions for installation and settings. App-SpaM is furthermore available as a Conda-package on the Bioconda channel.

Contact

matthias.blanke@biologie.uni-goettingen.de

Supplementary information

Supplementary data are available at Bioinformatics Advances online.
WikiNetworks: translating manually created biological pathways for topological analysis
Authors: Palshikar Mukta G , Hilchey Shannon P , Zand Martin S , Thakar Juilee
Published: October 2021

WikiPathways is a database of 2979 biological pathways across 31 species created using the drawing software PathVisio. Many of these pathways are not directly usable for network-based topological analyses due to differences in curation styles and drawings. We developed the WikiNetworks package to standardize and construct directed networks by combining geometric information and manual annotations from WikiPathways. WikiNetworks performs significantly better than existing tools. This enables the use of high-quality WikiPathways resource for network-based topological analysis of high-throughput data.

Availability and implementation

WikiNetworks is written in Python3 and is available on github.com/Thakar-Lab/wikinetworks and on PyPI.

Supplementary information

Supplementary data are available at Bioinformatics online.
BERT-Kcr: prediction of lysine crotonylation sites by a transfer learning method with pre-trained BERT models
Authors: Qiao Yanhua , Zhu Xiaolei , Gong Haipeng
Published: October 2021

Motivation

As one of the most important post-translational modifications (PTMs), protein lysine crotonylation (Kcr) has attracted wide attention, which involves in important physiological activities, such as cell differentiation and metabolism. However, experimental methods are expensive and time-consuming for Kcr identification. Instead, computational methods can predict Kcr sites in silico with high efficiency and low cost.

Results

In this study, we proposed a novel predictor, BERT-Kcr, for protein Kcr sites prediction, which was developed by using a transfer learning method with pre-trained bidirectional encoder representations from transformers (BERT) models. These models were originally used for natural language processing (NLP) tasks, such as sentence classification. Here, we transferred each amino acid into a word as the input information to the pre-trained BERT model. The features encoded by BERT were extracted and then fed to a BiLSTM network to build our final model. Compared with the models built by other machine learning and deep learning classifiers, BERT-Kcr achieved the best performance with AUROC of 0.983 for 10-fold cross validation. Further evaluation on the independent test set indicates that BERT-Kcr outperforms the state-of-the-art model Deep-Kcr with an improvement of about 5% for AUROC. The results of our experiment indicate that the direct use of sequence information and advanced pre-trained models of NLP could be an effective way for identifying PTM sites of proteins.

Availability and implementation

The BERT-Kcr model is publicly available on http://zhulab.org.cn/BERT-Kcr_models/.

Supplementary information

Supplementary data are available at Bioinformatics online.