bluuebunny/crossref_metadata_2025 huggingface dataset:
The model of particles modes. I. A paradigm for phase synchronization in tokamak turbulence
Authors: Ghizzo A. , Del Sarto D.
Published: April 2022

Superthermal energetic particles may alter the kinetic and resonant nature of zonal flows by leading to new types of instabilities. Here, we study the effects induced by superthermal energetic ions on trapped-ion modes (TIM) by using a reduced Hamiltonian gyrokinetic model, where both fast scales (cyclotron and bounce or transit motions) are gyro-averaged. In particular, we analyze the enhancement of resonant processes induced by energetic ions associated with nonlinear phase synchronization, in an extended version of the TIM model including circulating ions. Once an energetic particle mode is driven unstable, a rich nonlinear dynamics is observed, which encompasses a frequency chirping associated with a synchronization process driven by TIM and a transition scenario. An equivalence with the classic Kuramoto model—the paradigm describing the synchronization of a system of coupled oscillators—explains much of this phenomenology.
Ultra-high liquid–solid thermal resistance using nanostructured gold surfaces coated with graphene
Authors: Herrero Cecilia , Joly Laurent , Merabia Samy
Published: April 2022

The search for materials with high thermal resistance has promising applications in thermoelectric devices and boiling crisis retardation. In this paper, we study the interfacial heat transfer between water and gold, nanostructuring the gold surface and coating it with graphene. By trapping air (or vacuum in our simulations) between graphene and the nanopatterned surface, we observe a considerable increase in the interfacial resistance compared to the planar gold situation, which is shown to scale with the effective graphene–gold contact surface for both monolayer and multilayer graphene. With the massive thermal resistances we predict (up to 200 nm in terms of Kapitza length), the system proposed here represents a robust alternative to superhydrophobic Cassie materials. Moreover, since the low thermal conductance is achieved primarily due to geometry (vacuum trapping), it is straightforward to extend our results to any material with a structure equivalent to that of the nanopatterned gold wall considered here.
Experimental study of acoustic superradiance from a rotating absorber
Authors: Liu Lianyun , Yu Yong , Hu Junlun , Zheng Xu , Qiu Yi , Hao Zhiyong
Published: April 2022

The concept that classic waves reflected from a rotating absorbing cylinder will be amplified is analogously linked to the Penrose superradiance that may extract energy from a rotating black hole. The superradiance of acoustic waves carrying orbital angular momentum (OAM) from a sound absorber has been demonstrated in a recently published experiment using two rotating microphones. The experiment showed that the waves were amplified by up to 30% when the rotation rate of the absorber satisfied the Zel’dovich condition. Here, we proposed an experimental method to detect acoustic superradiance by static microphones. We demonstrated that the acoustic waves transmitted through a perforated absorber were amplified (by up to 1000%) even when the Zel’dovich condition was not satisfied. The experiment also showed that when the Doppler-shifted frequency of an observer was 0 Hz, the acoustic amplitude was very weak regardless of the rotation rate of the absorber. Our work was worthwhile not only in the proposed experimental method that was well-suited for observing the acoustic OAM wave but also in the high amplification achieved at a low rotation rate of the perforated absorber, showing a great prospect in practical applications such as amplifying the information-carrying OAM waves for high-speed acoustic communication.
Van der Waals heterostructures based on 2D layered materials: Fabrication, characterization, and application in photodetection
Authors: Yao Jiandong , Yang Guowei
Published: April 2022

Construction of heterostructures has provided a tremendous degree of freedom to integrate, exert, and extend the features of various semiconductors, thereby opening up distinctive opportunities for the upcoming modern optoelectronics. The abundant physical properties and dangling-bond-free interface have enabled 2D layered materials serving as magical “Lego blocks” for building van der Waals heterostructures, which bring about superior contact quality (atomically sharp and distortionless) and the combination of functional units with various merits. Therefore, these heterostructures have been the focus of intensive research in the past decade. This Tutorial begins with a variety of strategies for fabricating van der Waals heterojunctions, categorized into the transfer-stacking method and in situ growth assembly method. Then, the techniques commonly exploited for characterizing the structure, morphology, band alignment, interlayer coupling, and dynamics of photocarriers of van der Waals heterojunctions are summarized, including Raman spectroscopy, photoluminescence spectroscopy, atomic force microscopy, conductive atomic force microscopy, Kelvin probe force microscope, ultraviolet photoelectron spectroscopy, transfer characteristic analysis, scanning photocurrent microscopy, etc. Following that, the application of various van der Waals heterojunctions for diverse photoelectric detection is comprehensively overviewed. On the whole, this Tutorial has epitomized the fabrication, characterization, and photodetection application of van der Waals heterostructures, which aims to provide instructive guidance for the abecedarians in this emerging field and offer impetus of advancing this rapidly evolving domain.
Formation, doping, and lithium incorporation in LiFePO4
Authors: Kuganathan Navaratnarajah , Chroneos Alexander
Published: April 2022

For over 25 years, lithium iron phosphate (LiFePO4) has been a material of interest for Li-ion batteries as it is environmentally benign, low cost, and structurally stable. Here, we employed density functional theory calculations to examine the formation of LiFePO4 via different reaction routes, intrinsic defect processes, solution of dopants, and impact of doping on its electronic structure. The most thermodynamically favorable process to synthesize LiFePO4 is predicted to be from its constitute elements in their standard states. The Li–Fe anti-site defect is the lowest defect energy process inferring the presence of a small amount of cation intermixing. The most promising isovalent dopants on the Li, Fe, P, and O are the Na, Ca, As, and S, respectively. The substitution of Ru for Fe is energetically favorable. The doping of Ge on the P site is a possible strategy to generate both Li interstitials and holes in this material. The stability of this material upon Li incorporation (up to four atoms per 112-atom supercell) was investigated. Although incorporation is slightly unfavorable, there is a clear enhancement in the incorporation with volume expansion. The insulating nature of this material is affected by the doping and incorporation of Li, which leads to the reduction of the bandgap.
Correlated KPFM and TERS imaging to elucidate defect-induced inhomogeneities in oxygen plasma treated 2D MoS2 nanosheets
Authors: Gupta Sanju , Johnston Ammon , Khondaker Saiful
Published: April 2022

Modulating physical and chemical properties of two-dimensional (2D) transition metal dichalcogenides (TMDCs) by defect engineering induced by oxygen plasma is actively pursued. In this work, exfoliated 2D MoS2 layers treated by medium power oxygen plasma for different times (0, 10, 20, 40, and 60 s) are investigated using Kelvin probe force microscopy and tip-enhanced Raman spectroscopy (TERS) besides micro-Raman and photoluminescence (PL) spectroscopy. Under oxygen plasma, defects (mono- and di-sulfur vacancies) and chemical oxidation are predominant from 0 (native defects) up to 40 s, while etching becomes dominant beyond 40 s for mono- (1L), bi- (2L), and tri- (3L) layer MoS2 with optimal defect density for four- (4L) and more layers. While Raman spectra exhibited lattice distortion (broadening of phonon bands) and surface oxidation by the presence of sub-stoichiometric molytrioxide MoO3 (i.e., MoO3–x or MoSxO2–x), the increased spectral weight of trions and quenching in PL spectra are observed with treatment time. The localized nanodomains (∼20–40 nm) and aggregated vacancies as nanovoids and intermixed MoS2/MoO3–x alloy are identified in near-field Raman spectra. The atomic force microscopy also showed defects aggregation, and Kelvin probe force microscopy revealed the work function (WF) increase from 4.98 to 5.56 eV, corroborating the existence of MoO3–x phase which enables doping and shift Fermi level. We also highlight the unique interaction between the gold substrate and the formed MoO3–x facilitating Mo6+ cation reduction to lower oxidation (i.e., Mo4+), thereby yielding intermediate oxidation states responsible for lower WF (ca. theoretical 6.3 eV for stoichiometric MoO3). Strong correlations among the work function and vibrational and optical responses are established while exploring the oxygen plasma-induced defects and changing the landscape on oxygen doping at the nanoscale with varying MoS2 layers, which are useful for heterogeneous electrocatalysis and applicable to other 2D-TMDCs.
Sub-10-nm ferroelectric Gd-doped HfO2 layers
Authors: Skopin E. V. , Guillaume N. , Alrifai L. , Gonon P. , Bsiesy A.
Published: April 2022

Sub-10 nm thick gadolinium-doped hafnia (Gd:HfO2) layers were grown in metal–insulator–metal (TiN/Gd:HfO2/TiN) stacks using a plasma-enhanced atomic layer deposition process. Thermally annealed Gd:HfO2 layers with a thickness of 8.8, 6.6, and 4.4 nm exhibited orthorhombic crystalline structure and showed ferroelectric properties. Indeed, polarization vs electric field hysteresis loops were recorded with 2Pr polarization ranging from 2 to 20 μC/cm2. The studied layers showed the same coercive electric field (∼2 MV/cm). Consequently, polarization switching voltage between +Pr and −Pr decreased down to 0.9 V for the thinnest layer. Remanent polarization cycling showed a strong wake-up effect, with no fatigue, up to 109, followed by a stabilization up to 1010 cycles, where 2Pr reached 33 μC/cm2 for 8.8 nm Gd:HfO2. This endurance result and the absence of noticeable remanent polarization fatigue can be attributed to the optimal chemical composition of the TiN/Gd:HfO2 interface, which is supposed to be at the origin of defect generation, mostly oxygen vacancies, that leads to ferroelectric polarization fatigue.
One-step synthesis of FeSe0.45Te0.55 single crystals without excess Fe content
Authors: Huang Shuting , Tu Yubing , Han Guanglei , Liu Zhen , Long Mingsheng , Hou Xingyuan , Han Tao , Shan Lei
Published: April 2022

Excess interstitial Fe atoms in as-grown FeSe1−xTex single crystals are unavoidable in the self-flux growing procedure. As harmful defects to the study of superconductivity and Majorana fermions, the excess Fe atoms are usually removed by the post-annealing procedure. This two-step method is mostly used to obtain high quality FeSe1−xTex single crystals in present studies. Here, we carried out a one-step way to synthesize FeSe1−xTex single crystals without excess Fe content using a chemical vapor transport method. By combining transport measurement, magnetic measurement, and local scanning tunneling microscopy measurement, we prove that there is no excess Fe content in our one-step grown FeSe0.45Te0.55 single crystals. This work provides a new convenient way to obtain pure FeSe0.45Te0.55 single crystals and may be helpful to better study this exotic material.
Impacts of ‘Curiosity’ baiting on feral cat populations in woodland habitats of Kangaroo Island, South Australia
Authors: Hohnen Rosemary , Smith James , Mulvaney Josh , Evans Tom , Mooney Trish
Published: April 2022

Context Across Australia, feral cat (Felis catus) control and eradication programs are conducted to conserve threatened and vulnerable species. Controlling feral cats effectively at a landscape scale, particularly in remote woodland habitats, remains a significant challenge. Unfortunately, some standard feral cat control methods, such as shooting and cage trapping, require road access. Poison baiting is one of the few methods available to control feral cat populations in remote and inaccessable areas. Aims We aimed to examine the impact of a Curiosity® (Scientec Research PTY LTD, Melbourne, Australia) baiting program on the feral cat population found in continuous woodland habitat of the Dudley Peninsula, on Kangaroo Island, South Australia. Methods The density of cats was monitored using camera traps set up across both treatment and control sites using a before–after control–impact approach. Feral cat density was calculated using a spatially explicit capture–recapture framework. In addition, 14 feral cats were GPS collared at the treatment site, and their status and location, before and after baiting, was monitored. Key results At the treatment site after baiting, feral cat density fell from 1.18 ± 0.51 to 0.58 ± 0.22 cats km−2. In total, 14 feral cats were GPS collared, and of those, eight were detected within the treatment zone during and after bait deployment. Six of those eight cats died shortly after baiting, likely from bait consumption. A new individual cat was detected in the treatment zone within 10 days of baiting, and within 20 days, four new individuals were detected. Both before and after baiting, the number of feral cat detections was highest on roads, suggesting cat recolonisation of baited areas may be assisted by roads. Conclusions Curiosity baiting was found to be an effective method for reducing the density of feral cats in continuous woodland habitats of Kangaroo Island. Roads may act as access routes aiding cat recolonisation. Implications Curiosity baiting programs on Kangaroo Island (and elsewhere) would benefit from incorporating follow-up control, particularly along roads, to target feral cats re-colonising the area.
Highly motile cells are metabolically responsive to collagen density
Authors: Zanotelli Matthew R. , Zhang Jian , Ortiz Ismael , Wang Wenjun , Chada Neil C. , Reinhart-King Cynthia A.
Published: April 2022

Altered tissue mechanics and metabolism have gained significant attention as drivers of tumorigenesis, and mechanoresponsive metabolism has been implicated in migration and metastasis. However, heterogeneity in cell populations makes it difficult to link changes in behavior with metabolism, as individual cell behaviors are not necessarily reflected in population-based measurements. As such, the impact of increased collagen deposition, a tumor-associated collagen signature, on metabolism remains ambiguous. Here, we utilize a wide range of collagen densities to alter migration ability and study the bioenergetics of individual cells over time. Sorting cells based on their level of motility revealed energetics are a function of collagen density only for highly motile cells, not the entire population or cells with low motility. Changes in migration with increasing collagen density were correlated with cellular energetics, where matrix conditions most permissive to migration required less energy usage during movement and migrated more efficiently. These findings reveal a link between matrix mechanics, migratory phenotype, and bioenergetics and suggest that energetic costs are determined by the extracellular matrix and influence cell motility.
Alcohol Consumption and Alcohol Home Delivery Laws during the COVID-19 Pandemic
Authors: Grossman Elyse R. , Benjamin-Neelon Sara E. , Sonnenschein Susan
Published: April 2022

Background: Alcohol consumption in the U.S. is a public health problem that has been exacerbated by the COVID-19 pandemic. Relatedly, many states have responded to COVID-19 by relaxing their alcohol laws, making it possible for adults to have alcohol delivered to their homes. This study sought to understand the impact of allowing alcohol home delivery on self-reported adult alcohol consumption in the US. Methods: In May 2020, we surveyed a convenience sample of U.S. adults over 21 years of age recruited through social media and listservs. Eight hundred and thirty-two participants completed the online survey: 84% were female, 85% were White, and 72% were between the ages of 26 and 49. Results: Twenty-one percent of participants who consumed alcohol in the past month had at least some alcohol delivered, with 60% having it delivered from liquor stores, restaurants, or bars. The remainder of the participants purchased the alcohol in-person or owned it pre-COVID-19. Participants who reported having alcohol delivered also reported consuming more drinks ( β = 13.3; 95% CI [8.2, 18.4]; p < .000) and drinking on more days ( β = 5.0; 95% CI [2.9, 7.0]; p < .000) over the past month than participants who obtained alcohol through other methods. Participants who had alcohol delivered were nearly two times more likely to report engaging in binge drinking than those who obtained alcohol through other methods ( OR = 1.96; 95% CI [1.3, 3.1]; p = .003). Conclusions: Obtaining alcohol through home delivery was associated with greater alcohol consumption including binge drinking. As states consider permanently allowing alcohol home delivery, it is important to consider the potential public health implications.
Generalized geodesic deviation in de Sitter spacetime
Authors: Waldstein Isaac Raj , Brown J David
Published: April 2022

The geodesic deviation equation (GDE) describes the tendency of objects to accelerate towards or away from each other due to spacetime curvature. The GDE assumes that nearby geodesics have a small rate of separation, which is formally treated as the same order in smallness as the separation itself. This assumption is discussed in various papers but is not articulated in any standard textbooks on general relativity. Relaxing this assumption leads to the generalized geodesic deviation equation (GGDE). We elucidate the distinction between the GDE and the GGDE by explicitly computing the relative acceleration between timelike geodesics in two-dimensional de Sitter spacetime. We do this by considering a fiducial geodesic and a secondary geodesic (both timelike) that cross with nonzero speed. These geodesics are spanned by a spacelike geodesic, whose tangent evaluated at the fiducial geodesic defines the separation. The second derivative of the separation describes the relative acceleration between the fiducial and secondary geodesics. Near the crossing point, where the separation between the timelike geodesics is small but their rates of separation can be large, we show that the GGDE holds but the GDE fails to apply.
Stress engineered SU-8 dielectric-microbridge based polymer MEMS Pirani gauge for broad range hermetic characterization
Authors: Garg Manu , Arya Dhairya Singh , Kumar Sushil , Yousuf Mujeeb , Chiu Yi , Singh Pushpapraj
Published: April 2022

The paper introduces a SU-8 dielectric µ-bridge based polymer microelectromechanical systems (MEMS) Pirani gauge which can be employed for hermetic characterization of packaged electronic sensors. The µ-bridge structure is adopted due to its simplicity in fabrication and lower footprint, which makes it feasible for heterogeneous integration. Further, the integration of SU-8 polymer with the active thermistor offers superior thermal isolation from the substrate and extends the dynamic range. Before fabricating the actual device, the SU-8 based µ-bridge is optimized for stress-free release. A stress engineering is performed and thermal processing of SU-8 is optimized. The measurement results reveal that the removal of quenching from the baking steps leads to the successful fabrication of freely suspended µ-bridge with SU-8 polymer as a structural layer. A quantitative comparison of the proposed gauge is established by comparing the gauge performance with conventional dielectric materials like silicon dioxide (SiO2), silicon nitride (Si3N4), and aluminum oxide (Al2O3). The fabricated SU-8 polymer-based MEMS Pirani gauge with a 40 µm × 7 µm footprint can be used for hermetic characterization from 30 Pa to 105 Pa and is an ideal candidate for heterogeneous integration.
Human coronavirus inactivation by atmospheric pressure helium plasma
Authors: Sasaki Shota , Osana Shion , Kubota Takahiro , Yamaya Mutsuo , Nishimura Hidekazu , Nagatomi Ryoichi , Kaneko Toshiro
Published: April 2022

The recent global pandemic of Corona Virus Disease-19 has impacted all aspects of society, producing a growing demand for a powerful virus inactivation method. To assess a potential and mechanism of human coronavirus inactivation using atmospheric pressure plasma (APP) technology, replication of a human coronavirus (HCoV-229E) after He + H2O APP plume exposure was evaluated using rhesus monkey kidney epithelial cells. The HCoV-229E titers were reduced by 3 log10TCID50 after the APP exposure for 30 s, showing a strong virus-inactivation efficacy of the APP. It was experimentally verified that the APP produced the liquid-phase reactive oxygen and nitrogen species (RONS) at high rates [e.g. •OH: ∼1.7 nmol s−1, H2O2 (including H2O2 precursors): ∼9.2 nmol s−1, NO2
− (including NO2
− precursors): ∼3.3 nmol s−1]. However, an administration of H2O2 with NO2
− failed to inactivate the virus and only Mn type superoxide dismutase among several RONS scavengers for •OH, HO2
•/O2
•−, 1O2, and •NO/•NO2 was significantly effective for the recovery of the APP-induced decrease in the viral titers. This suggests O2
•−-related chemical reaction in a network of interconnected reactions induced by the APP exposure is very important for the APP-induced virus inactivation. These results provide new insight into a more efficient inactivation method of human coronavirus using APPs.
Effect of non-magnetic doping on magnetic state and Li/Na adsorption and diffusion of black phosphorene
Authors: Zhong Kehua , Li Jiaxin , Xu Guigui , Zhang Jian-Min , Huang Zhigao
Published: April 2022

Black phosphorene (BP) have aroused great concern because of its great potential for the application in nanoelectronic devices and high-performance anode materials for alkali metal ion batteries (AIBs). However, the absence of magnetism for an ideal BP limits its wide application in spintronic devices which is one of the important nanoelectronic devices, and its application as a high-performance anode material for AIBs is still to be explored. In this paper, we adopt first-principles calculations to explore the effects of B, C, N, O, F, Al, Si and S atom doping on the magnetic state of monolayer BP and Li or Na atom adsorption and diffusion on the BP. Additionally, the thermal stability of the doped BP systems at room temperature is revealed by the ab initio molecular-dynamics calculations. Our calculated results indicate that O and S doping can make the doped BP become a magnetic semiconductor, C and Si doping makes the doped BP be metallic, and B, N, F and Al doping preserves semiconductor property. Moreover, little structural changes and significant decreases of diffusion barriers in armchair direction and slight increases of diffusion barriers in zigzag direction make B-doped BP beneficial as an anode material for lithium-ion batteries (LIBs) and sodium-ion batteries (SIBs). It reveals that S-doping is suitable for improving the performance of SIBs rather than LIBs. Interestingly, it is found that magnetic states of O- and S-doped BP disappear when Li or Na atoms adsorb on them, whereas Li or Na adsorption on B- and Al-doped BP induces magnetic states of these systems. The analyses indicate that the distinct electron transfer between the dopant atom, adatom and neighboring P atoms, and specific electron configuration of dopant atoms cause the magnetism of the systems. Our results suggest that selecting appropriate composition to dope can effectively manipulate magnetic state and improve Li/Na adsorption and diffusion on the BP. These results may inspire further theoretical and experimental exploration on doped two-dimensional (2D) materials in spintronics and doped 2D promising anode materials for high-performance metal ion batteries.
Atomic structure of an FeCrMoCBY metallic glass revealed by high energy x-ray diffraction
Authors: Pussi K , Louzguine-Luzgin D V , Nokelaineni J , Barbiellini B , Kothalawala V , Ohara K , Yamada H , Bansil A , Kamali S
Published: April 2022

Amorphous bulk metallic glasses with the composition Fe48Cr15Mo14C15B6Y2 have been of interest due to their special mechanical and electronic properties, including corrosion resistance, high yield-strength, large elasticity, catalytic performance, and soft ferromagnetism. Here, we apply a reverse Monte Carlo technique to unravel the atomic structure of these glasses. The pair-distribution functions for various atomic pairs are computed based on the high-energy x-ray diffraction data we have taken from an amorphous sample. Monte Carlo cycles are used to move the atomic positions until the model reproduces the experimental pair-distribution function. The resulting fitted model is consistent with our ab initio simulations of the metallic glass. Our study contributes to the understanding of functional properties of Fe-based bulk metallic glasses driven by disorder effects.
Improvement of wire-mesh sensor accuracy via adapted circuit design and integrated energy loss measurement
Authors: Dias Felipe de Assis , Wiedemann Philipp , Schleicher Eckhard , da Silva Marco Jose , Hampel Uwe
Published: April 2022

We reviewed the electronic principles and design of the wire-mesh sensor with respect to inherent energy losses. From the analysis we derived a new circuit design with an optimized amplifier circuit and extended the sensor by an extra transmitter electrode embedded into the dielectric construction material. The latter allows an inherent determination of the energy losses that cannot be suppressed by circuit optimization only. Experimental analysis showed that we achieve an improvement in measurement accuracy with respect to the local and average phase fractions. Deviations in a single crossing point are reduced from more than

30
%

down to less than

5
%

and deviations in the average phase fraction are reduced from more than

15
%

down to less than

2
%

.
First-order thermodynamics of scalar-tensor cosmology
Authors: Giardino Serena , Faraoni Valerio , Giusti Andrea
Published: April 2022

A new thermodynamics of scalar-tensor gravity is applied to spatially
homogeneous and isotropic cosmologies in this
class of theories and tested
on analytical solutions. A forever-expanding universe approaches the
Einstein “state of equilibrium” with zero effective temperature at late
times and departs from it near spacetime singularities. “Cooling” by
expansion and “heating” by singularities compete near the Big Rip, where
it is found that the effective temperature diverges in the case of
a conformally coupled scalar field.
Post-Newtonian parameters of ghost-free parity-violating gravities
Authors: Qiao Jin , Zhu Tao , Li Guoliang , Zhao Wen
Published: April 2022

We investigate the slow-motion and weak-field approximation of the general ghost-free parity-violating (PV) theory of gravity in the parametrized post-Newtonian (PPN) framework and derive the perturbative field equations, which are modified by the PV terms of this theory. The complete PPN parameters are obtained by solving the perturbative field equations. We find that all the PPN parameters are exactly the same as those in general relativity, except for an extra parameter κ, which is caused by the new curl-type term in the gravitomagnetic sector of the metric in this theory. We calculate the precession effects of gyroscopes in this theory and constrain the model parameters by the observations of the Gravity Probe B experiment.
Optical theorem, crossing property, and derivative dispersion relations: implications on the asymptotic behavior of

and
Authors: Campos S. D. , Okorokov V. A.
Published: April 2022

In this paper, we present some results on the behavior of the total cross section and ρ-parameter at asymptotic energies in proton–proton (

) and antiproton–proton (

) collisions. Hence, we consider three of the main theoretical results in high energy physics: the crossing property, derivative dispersion relation, and optical theorem. The use of such machinery facilitates the derivation of analytic formulas for a wide set of the measured global scattering parameters and some important relations between them. The suggested parameterizations approximate the energy dependence for the total cross section and ρ-parameter for

and

with a statistically acceptable quality in the multi-TeV region. Additionally, the qualitative description is obtained for important interrelations, namely difference, sum, and ratio of the antiparticle–particle and particle–particle total cross sections. Despite the reduced number of experimental data for the total cross section and ρ-parameter at the TeV-scale, which complicates any prediction for the beginning of the asymptotic domain, the fitting procedures indicates that asymptotia occur in the energy range 25.5–130 TeV. Moreover, in the asymptotic regime, we obtain

. A detailed quantitative study of the energy behavior of the measured scattering parameters and their combinations in the ultra–high energy domain indicates that the scenario with the generalized formulation of the Pomeranchuk theorem is more favorable with respect to the original formulation of this theorem.
Review Article: Resonant Families of Periodic Orbits in the Restricted Three-body Problem*
Authors: Pan Shanshan , Hou Xiyun
Published: April 2022

The restricted three-body problem (RTBP) is a fundamental model in celestial mechanics. Periodic orbits in the synodic frame play a very important role in understanding the dynamics of the RTBP model. Most of these periodic orbits, when interpreted in the sidereal frame, are actually resonant periodic orbits. As a result, numerical computation of the periodic orbits is also one approach for researchers to understand the orbital resonances of the three-body problem. Extensive studies have been carried out on this topic, concerning either the circular case or the elliptic case of this model. In this paper, we make a brief review of the history and current status of the studies on resonant periodic orbits in the RTBP model. Starting from the unperturbed two-body problem, we organize the review paper by the two cases of this model—the circular restricted three-body problem and the elliptic restricted three-body problem.
Optimization Design of Short Shell Structure of Rocket Fuel Tank Based on Kriging Surrogate Model
Authors: Luo Zheng , Liu Zeya , He Xiaoyu
Published: April 2022

Aiming at the weight reduction optimal design of short shell structure of rocket fuel tank, this paper deals with the structural optimization under the action of axial load. First, the accuracy of equivalent stiffness method is verified by post-buckling analysis of short shell in ABAQUS. Then, according to the parametric model of short shell, based on Kriging surrogate model and EGO algorithm, the optimal structure without and with fillet are obtained under the given design load. Finally, a parametric study is carried out on the influence of fillet on the bearing capacity per unit mass of short shell. The results show that when the width of rib or the spacing of transverse rib is small, and the height of rib, the thickness of skin or the spacing of longitudinal rib is large, processing large fillet for load-bearing purpose is less beneficial or even disadvantageous.
Research on the Built-in Test Design of Civil Aircraft Flight Control System
Authors: Shen Shilei , Ma Linlong
Published: April 2022

Based on ARINC 624 for civil aircraft airborne maintenance system, the working modes and application forms of civil aircraft Flight Control System Built-in Test (BIT) design are given. The test principles and implementation methods of the civil aircraft Flight Control System Power-on BIT and Initiated BIT are analyzed in detail, and the overall functional architecture of the civil aircraft Flight Control System BIT is described. Taking the actuator as an example, the realization method of its return to service test is analyzed. Finally, the general characteristics of the BIT technology of the civil aircraft Flight Control System are summarized.
Study on the combination influences of homotype rough element on hypersonic blunt cone flow
Authors: Tang Xiaojun , Liu Lixia , Sun Zijie , Xin Liang , Shi Mingfang
Published: April 2022

To study the influence of the homotype rough element combination and spacing on the flow around the hypersonic blunt cone, the high-order accuracy finite difference method is used to directly simulate the flow field around the hypersonic compressible blunt cone, and the influence of the homotype of rough element on the boundary layer parameters such as heat flux and friction coefficient is discussed. It is concluded that two K-type rough elements lead to the formation of three compression waves and two expansion waves in the flow field. On the contrary, two D-type rough elements form two compression waves and three expansion waves in the flow field, and a long flow separation will be formed between two K-type and D-type rough elements. When the spacing of rough elements is 1, the drag reduction and heat reduction effect of K+K rough element is better than that of D+D rough element. When the spacing between the two rough elements is greater than a certain length, the two rough elements will not affect each other.
A model for a metal bobbin tile with open cylindrical shell structures
Authors: Wang Zhaodong , Li Pu
Published: April 2022

Correct modeling of static stiffness and strength of the metal bobbin tile is crucial in the design of roof structures. In the past, finite element method (FEM) is the only accurate way to evaluate stiffness and strength of the metal tile. In this paper, the single metal bobbin tile is first treated as an open cylindrical shell. Then an analytical model for the static stiffness of the metal bobbin tile under concentrated load is presented based on a double triangular series. The accuracy of the present models is verified by comparing their results with the numerical results of FEM.
Synthesis analysis of electric propulsion implement in large civil aircraft
Authors: Dong Qinpeng , Ma Chao
Published: April 2022

With more and more concerns of carbon emission reduction in civil aviation, this article aims to illustrate the current development and product of electric propulsion in civil aviation, also to investigate the feasibility and benefit of electric propulsion implement on large civil aircraft. In order to achieve this objective, a single aisle passenger airliner concept with electric propulsion was designed and trade-studied. There are both advantages and disadvantages of different energy architecture such as Turbine generator, APU generator, Lithium battery and Hydrogen fuel cell system. As the practical energy density of lithium battery is much lower than needed, considering the current situation and development potential, fuel cell with liquid hydrogen are most possibly used as the main power source in future large civil aircraft.
Numerical Simulation Of Propellant Slurry Stirring Process
Authors: Zhao Ruyan , Huang Jingru , Zhuang Zhenmin , Guan Xu
Published: April 2022

Taking the mixing process of medicine slurry in kneader as the research object, the finite element analysis method was used to simulate the law and characteristics of TCM slurry flow in the mixing process. The simulation results show that the telocentric blade plays an important role in the stirring process. The scraping area of telecentric blades and the kneading area of two blades are the main kneading areas. The flow direction of slurry does not change at different speeds, and the velocity has a linear relationship with the blade speed. The axial conveying capacity is the best at the central horizontal section of the mixing kettle. When the rotational speed increases, the shear stress and viscous heat loss rate increase, and the viscosity decreases.
A circuit design framework of electromagnetic wave resistivity logging while drilling instrument
Authors: Wu Yao , Yang Hao , Meng Zhuoran , Wei Yiduo , Liu Xiangzheng , Li Anzong
Published: April 2022

Formation resistivity is an important geological parameter necessary for geosteering drilling and oilfield formation evaluation. At present, the mainstream resistivity measurement methods mainly include current measurement and electromagnetic wave measurement. Current resistivity measurement is difficult to be applied in drilling fluids with poor conductivity or non-conductivity, while electromagnetic wave resistivity measurement is suitable for various types of conductive and non-conductive drilling fluids. Nowadays, the most important geological guiding tool for Sichuan-Chongqing Shale Gas, Xinjiang Oilfield, Jilin Oilfield, Daqing Oilfield and Qinghai Oilfield Company rely on electromagnetic wave resistivity measurement, and the market demand is about 90 million yuan per year. Western Drilling, Chuanqing Drilling and Bohai Drilling have more than 100 branches of electromagnetic wave resistivity logging while drilling instrument, and the market demand is about 21 ∼30 million yuan per year. Domestic electromagnetic wave resistivity logging while drilling instrument mainly rely on imports. At the same time, after field application, it needs to be sent back to the original factory for maintenance. Therefore, it is very necessary to design an electromagnetic wave resistivity logging while drilling instrument with independent intellectual property rights.
Application of oscillatory time frequency manifold for extraction of rolling element bearing fault signature
Authors: Li Lei , Noman Khandaker , Li Yongbo , Fu Hao , Deng Zichen
Published: April 2022

To overcome the problem that traditional feature extraction algorithms are sensitive to noise, a bearing fault signature extraction scheme is proposed in this paper with the help of oscillation-based signal decomposition and time frequency manifold (TFM) learning. Firstly, an oscillation-based signal component separation method based on tunable Q factor wavelet transform (TQWT) is utilized to separate the low oscillatory component from vibration signals. Then, concept of TFM is utilized on the separated low oscillatory component to generate the low oscillatory time frequency manifold signature. The proposed method is termed as oscillatory time frequency manifold (OTFM). Compared to that of traditional short time Fourier transform (STFT) and original TFM algorithm, results of experiment show that the proposed algorithm has better time frequency characterization ability for bearing fault signature.
Dynamic trajectory tracking method of UAV using L1 Adaptive Control
Authors: Xie Kaizhou , Gong Zheng , Bai Yalei
Published: April 2022

An attitude control method based on the L1 adaptive structure was proposed for the quadrotor aircraft with nonlinear, strong coupling, and underactuated characteristics during flight. Then introducing a dynamic point trajectory algorithm to solve the problem that traditional linear controller lacks robustness in the quadrotor aircraft. The adaptive controller can quickly estimate the state of the system then track and compensate for interference items. The dynamic point trajectory algorithm was able to calculate the expected trajectory and trajectory deviation of the disturbed aircraft, which improved the anti-interference ability and fault tolerance ability of the system. The simulation results indicate that the flight control system designed based on the L1 adaptive dynamic point method is qualified for achieving high-precision trajectory tracking control and the system has strong anti-interference capability and robustness in the nonlinear state.
Flight Control Simulation and Flight Test of Foldable Rotor UAV
Authors: Xu Jiulong , Hao Yongping , Wang Shoutai
Published: April 2022

Aiming at the short endurance time of micro-rotor UAV, based on the analysis of the structural characteristics and the working principle of rotor UAV, a design scheme of foldable quad-rotor UAV based on c is proposed. The feasibility of cascade PID control method is verified by co-simulation and analysis with ADAMS dynamics simulation software and MATLAB. Through the comparison of the flight test results, the feasibility of the designed control algorithm for the attitude control of the foldable quadrotor UAV is verified. Flight test shows that the UAV can achieve foldable function on the basis of stable hovering and high flight, achieved good results.
Research on Space Rapid Response Launch System based on Data Link
Authors: Wu Feng , Wang Jia , Liu Ying , Liu Yang , Wang Min
Published: April 2022

Space rapid response launch system based on data link is relying on high orbit communication satellites and low orbit comprehensive constellation, to construct the data link tactical time-sensitive network space-based plane, with features of full coverage, wide area interconnection, machine interconnection, flat networking and mobile disturbance rejection, to provide the wide-area multi-field, ocean-sea container, multi-batch rapid response launch capability. This paper has carried out the research on application requirements in combination of the data link and the space rapid response launch, the basic structure of space rapid response launch system based on data link, and the adaptive design method of the rocket and launch unit, so as to promote the generation of multi-domain self-organizing collaborative launch capability.
Research on Prognostic and Health Management of Inertial Navigation System
Authors: Wu Ji
Published: April 2022

Prognostic and health management (PHM) system significantly reduces costs of maintenance, utilization, and assurance, and improves safety and availability of aircraft. By drawing on and absorbing foreign advanced experience, this paper deeply studies the key technology of PHM, and combines the specific features of the inertial navigation system to determine the program flow of the PHM system. This paper is described PHM technical related elements, which can be reformed the design of Inertial Navigation System and can push the development of the condition-based maintenance and PHM system.
Multi-task graph neural networks for simultaneous prediction of global and atomic properties in ferromagnetic systems
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Authors: Lupo Pasini Massimiliano , Zhang Pei , Temple Reeve Samuel , Youl Choi Jong
Published: April 2022

We introduce a multi-tasking graph convolutional neural network, HydraGNN, to simultaneously predict both global and atomic physical properties and demonstrate with ferromagnetic materials. We train HydraGNN on an open-source ab initio density functional theory (DFT) dataset for iron-platinum with a fixed body centered tetragonal lattice structure and fixed volume to simultaneously predict the mixing enthalpy (a global feature of the system), the atomic charge transfer, and the atomic magnetic moment across configurations that span the entire compositional range. By taking advantage of underlying physical correlations between material properties, multi-task learning (MTL) with HydraGNN provides effective training even with modest amounts of data. Moreover, this is achieved with just one architecture instead of three, as required by single-task learning (STL). The first convolutional layers of the HydraGNN architecture are shared by all learning tasks and extract features common to all material properties. The following layers discriminate the features of the different properties, the results of which are fed to the separate heads of the final layer to produce predictions. Numerical results show that HydraGNN effectively captures the relation between the configurational entropy and the material properties over the entire compositional range. Overall, the accuracy of simultaneous MTL predictions is comparable to the accuracy of the STL predictions. In addition, the computational cost of training HydraGNN for MTL is much lower than the original DFT calculations and also lower than training separate STL models for each property.
Expanding the Galaxy’s reference data
Authors: VijayKrishna Nagampalli , Joshi Jayadev , Coraor Nate , Hillman-Jackson Jennifer , Bouvier Dave , van den Beek Marius , Eguinoa Ignacio , Coppens Frederik , Davis John , Stolarczyk Michał , Sheffield Nathan C , Gladman Simon , Cuccuru Gianmauro , Grüning Björn , Soranzo Nicola , Rasche Helena , Langhorst Bradley W , Bernt Matthias , Fornika Dan , de Lima Morais David Anderson , Barrette Michel , van Heusden Peter , Petrillo Mauro , Puertas-Gallardo Antonio , Patak Alex , Hotz Hans-Rudolf , Blankenberg Daniel
Published: April 2022

Properly and effectively managing reference datasets is an important task for many bioinformatics analyses. Refgenie is a reference asset management system that allows users to easily organize, retrieve and share such datasets. Here, we describe the integration of refgenie into the Galaxy platform. Server administrators are able to configure Galaxy to make use of reference datasets made available on a refgenie instance. In addition, a Galaxy Data Manager tool has been developed to provide a graphical interface to refgenie’s remote reference retrieval functionality. A large collection of reference datasets has also been made available using the CVMFS (CernVM File System) repository from GalaxyProject.org, with mirrors across the USA, Canada, Europe and Australia, enabling easy use outside of Galaxy.

Availability and implementation

The ability of Galaxy to use refgenie assets was added to the core Galaxy framework in version 22.01, which is available from https://github.com/galaxyproject/galaxy under the Academic Free License version 3.0. The refgenie Data Manager tool can be installed via the Galaxy ToolShed, with source code managed at https://github.com/BlankenbergLab/galaxy-tools-blankenberg/tree/main/data_managers/data_manager_refgenie_pull and released using an MIT license. Access to existing data is also available through CVMFS, with instructions at https://galaxyproject.org/admin/reference-data-repo/. No new data were generated or analyzed in support of this research.
CLIN-X: pre-trained language models and a study on cross-task transfer for concept extraction in the clinical domain
Authors: Lange Lukas , Adel Heike , Strötgen Jannik , Klakow Dietrich
Published: April 2022

Motivation

The field of natural language processing (NLP) has recently seen a large change toward using pre-trained language models for solving almost any task. Despite showing great improvements in benchmark datasets for various tasks, these models often perform sub-optimal in non-standard domains like the clinical domain where a large gap between pre-training documents and target documents is observed. In this article, we aim at closing this gap with domain-specific training of the language model and we investigate its effect on a diverse set of downstream tasks and settings.

Results

We introduce the pre-trained CLIN-X (Clinical XLM-R) language models and show how CLIN-X outperforms other pre-trained transformer models by a large margin for 10 clinical concept extraction tasks from two languages. In addition, we demonstrate how the transformer model can be further improved with our proposed task- and language-agnostic model architecture based on ensembles over random splits and cross-sentence context. Our studies in low-resource and transfer settings reveal stable model performance despite a lack of annotated data with improvements of up to 47 F1 points when only 250 labeled sentences are available. Our results highlight the importance of specialized language models, such as CLIN-X, for concept extraction in non-standard domains, but also show that our task-agnostic model architecture is robust across the tested tasks and languages so that domain- or task-specific adaptations are not required.

Availability and implementation

The CLIN-X language models and source code for fine-tuning and transferring the model are publicly available at https://github.com/boschresearch/clin_x/ and the huggingface model hub.