bluuebunny/crossref_metadata_2025 huggingface dataset:
The Northwest Offshore Otway Basin Well Folio
Authors: Nguyen Duy , Edwards Dianne S. , Gunning Merrie-Ellen , Bernardel George
Published: May 2022

The Otway Basin is a northwest–southeast trending rift basin which spans from onshore Victoria and South Australia into the deep-water offshore. The prospective supersequences within the basin are largely of Cretaceous age that host three possible petroleum systems (Austral 1, 2 and 3). While there is production from onshore depocentres, and the inboard Shipwreck Trough, the majority of the offshore basin remains underexplored. Recent regional studies have highlighted the need for further work across the underexplored parts of the basin and here we focus on the offshore northwest Otway Basin, integrating reinterpreted historical well data, newly acquired and recently reprocessed seismic data. This new Well Folio consists of composite logs and supporting data, which includes interpreted lithologies, petrophysical analyses, the analysis of historic organic geochemistry and organic petrology. In addition, updated well markers are provided based on seismic interpretation and new biostratigraphy in key wells. This integrated study provides the basis for renewed prospectivity assessment in the northwest offshore portion of the Otway Basin.
A report of direct mortality in grey-headed flying-foxes (
Authors: Mo Matthew , Minehan Mark , Hack Edward , Place Vanessa , Welbergen Justin A.
Published: May 2022

Study of the impacts of the 2019–2020 Black Summer bushfires on flying-foxes has mainly focused on the effects of burnt habitat on food availability. It has previously only been assumed that flying-foxes probably died directly from these bushfires. We report an eyewitness account of numbers of grey-headed flying-foxes (Pteropus poliocephalus) being killed as they attempted to escape a bushfire engulfing a flying-fox camp in Jeremadra, New South Wales. Once in the air, most of the flying-foxes dropped to the ground, scattering carcasses throughout the vicinity. This observation represents the only eyewitness report of flying-fox mortalities occurring directly from these bushfires. Given the substantial proportion of the grey-headed flying-fox range affected by these bushfires, we infer that such mortalities likely occurred in other locations.
Use of artificial bark covers to investigate the distribution and abundance of arboreal lizards in a floodplain environment
Authors: Moore Eva , Nimmo Dale G. , Wassens Skye , Michael Damian R.
Published: May 2022

Arboreal lizards, especially species that inhabit flood-prone environments, have been poorly surveyed worldwide. We examined spatiotemporal patterns in arboreal lizard abundance and factors driving detection rates in floodplain environments using artificial bark covers, a non-destructive and cost-effective survey method. In total, 112 flexible, closed-cell foam bark covers were installed on eucalypt trees in 13 wetlands in the Murrumbidgee River floodplain of southern New South Wales, Australia, stratified by two inundation frequency treatments. Of four arboreal lizard species detected, the southern marbled gecko (Christinus marmoratus) (n = 41) and the tree dtella (Gehyra versicolor) (n = 8) were restricted to the mid-Murrumbidgee region, whereas the crevice skink (Egernia striolata) (n = 19) was restricted to the lower-Murrumbidgee region and did not co-occur with either gecko species. Mean detection rates of lizard species did not differ between frequently and infrequently inundated treatments but their abundance beneath covers varied significantly by month. For all detected lizard species, the presence/absence of the arachnid Holconia murrayensis represented a significant variable in explaining lizard occurrence patterns, particularly that of C. marmoratus. Artificial bark covers are a useful survey method for collecting distribution, abundance, and occupancy data on floodplain reptiles, although detection rates can be affected by the month, predator–prey interactions, and survey effort. Adopting passive, non-destructive reptile survey methods would greatly improve our knowledge of species’ distributions and abundance patterns in vegetation communities subject to disturbance events.
Role of dynamic bonds on fatigue threshold of tough hydrogels
Authors: Li Xueyu , Gong Jian Ping
Published: May 2022

Significance

Dynamic bonds have been found to enhance fracture toughness of hydrogels as sacrificial bonds, but the role of dynamic bonds to fatigue threshold of hydrogels is poorly understood because the wide dynamic range of viscoelastic response imposes a challenge on fatigue experiments. Here, by using polyampholyte hydrogels, we adopted a time–salt superposition principle to access a wide range of time scales that are otherwise difficult to access in fatigue tests. Relations between fatigue threshold and strain rate in elastic and viscoelastic regimes and the corresponding mechanism correlated to permanent/dynamic bonds were revealed. We believe that this work gives important insight into the design and development of fatigue-resistant soft materials composed of dynamic bonds.
Variation versus deviation
Authors: Requena Pablo E.
Published: May 2022

Naturalistic production research has reported that, unlike monolingual peers, children acquiring Spanish as a
heritage language omit Differential Object Marking (DOM) with animate objects since the earliest stages of language development.
However, the previous studies investigating longitudinal monolingual and bilingual corpora cannot be compared to each other given
their different treatment of language-internal variation in DOM use along the animacy scale. Whereas monolingual results excluded
contexts predicted to be variable, bilingual results combined them with categorical contexts increasing the rate of “errors” in
the bilingual group. This study reexamines naturalistic production by monolingual and early bilingual children as well as by their
caregivers using a common methodology that distinguishes categorical from variable DOM contexts. The results indicate that
longitudinal corpora covering child heritage speakers’ development up to age three do not show evidence of greater omission of DOM
compared to monolingual children once variability along the animacy scale is accounted for. By contrast, young monolingual and
bilingual children’s use of Spanish DOM seems target-like based on their input.
Ignition thresholds and flame propagation of methane-air mixture: detailed kinetic study coupled with electrical measurements of the nanosecond repetitively pulsed plasma discharges
Authors: Mehdi Ghazanfar , Fontanarosa Donato , Bonuso Sara , De Giorgi Maria Grazia
Published: May 2022

This study investigated the effects of nanopulsed plasma discharge on combustion enhancement. A disk-ring plasma actuator was developed to be applied to a rectangular cross-sectional burner. Experiments tests were performed with different applied voltages to estimate reduced electric field (E
N), mean power and the energy input (E
i) to be coupled with numerical analysis. The validation of the plasma chemistry model was carried out using ZDPlaskin numerical solver by comparing the experimental data of mole fraction of O atoms available in the literature. Plasma chemistry computations based on an extended kinetic mechanism of methane/air mixtures were performed by ZDPlasKin. Then, the results obtained by the ZDPlasKin in the form of kinetic effects (concentrations of O, OH, O3, CH, CH3, and H) and thermal effects (joule heating) were used in CHEMKIN to evaluate the combustion enhancement. Flame speed considerably increased with plasma discharge and maximum enhancement has been observed at about 20.9%. The flame temperature corresponding to the peak of heat release rate gets lower with the increase of the E
i value. It has been observed that in a clean case, a lower flammability limit was retrieved at φ = 0.6, but in presence of plasma, it was reduced to φ = 0.5. The plasma actuation significantly reduced the time necessary to reach the ignition temperature with respect to autoignition (clean case). The maximum reduction of ignition delay timing was noticed at E
i = 10.11 mJ cm−3 and E
N = 200 Td, with a value between 10−8 and 10−7 s, significantly lower than the autoignition case is between 10−3 and 10−2 s. Adding to this, ignition analysis was also performed at low inlet temperatures. Results demonstrated that it was possible to reach ignition of CH4/air mixture at a lower inlet temperature than the one required for self-ignition (without plasma), meaning that ignition is even possible in cold flow conditions using plasma. Finally, thermal and kinetic effects of plasma discharge on the ignition enhancement of methane–air mixture have been predicted. It concluded the ignition improvement is mainly due to O, H, and OH species, while the thermal effect was negligible.
Electron transfer driven by tip-induced flexoelectricity in contact electrification
Authors: Lin Shiquan , Zheng Mingli , Xu Liang , Zhu Laipan , Wang Zhong Lin
Published: May 2022

Contact electrification (CE) has been known for over 25 centuries, but the origin of the CE remains mysterious. Recent theoretical studies suggest that flexoelectricity may drive the CE, but experimental evidence is lacking. Here, the CE between a nanoscale tip and flat polymers is studied by using atomic force microscopy. The contributions of flexoelectricity to the CE are analyzed. We focus on the effect of the load, which is coupled to the strain gradient at the contact region. It is revealed that the flexoelectric polarization in general polymers can drive electron transfer, and even reverse the intrinsic polarity of electron transfer in the CE. It implies that the flexoelectricity is one of the driving forces for the CE. The flexoelectricity induced electric field is measured by applying a voltage between the tip and the sample, which counteracts the flexocoupling voltage. Further, a band structure model is proposed, in which the surface states of the solid are suggested to be shifted by the flexoelectric polarization.
1D-DRSETL: a novel unsupervised transfer learning method for cross-condition fault diagnosis of rolling bearing
Authors: Tong Jinyu , Liu Cang , Zheng Jinde , Pan Haiyang , Wang Xiaoyu , Bao Jiahan
Published: May 2022

Transfer learning can meet the challenge of cross-condition fault diagnosis. However, the diagnostic effectiveness of transfer learning in actual applications is unsatisfactory, mainly due to the great unbalance in labeling between testing and training samples. A one-dimensional dual residual squeeze-and-excitation transfer learning network (1D-DRSETL) is proposed for an unsupervised accurate intelligent diagnosis under cross-condition in this paper for unlabeled small sample. First, a special block is designed to obtain transferable features by adaptively focusing on fault-sensitive information. Second, the joint maximum mean discrepancy is utilized to deal with the feature matching problem under cross-conditions. Then, speed up model training with AdaBelief optimizer. Finally, cross-conditions transfer diagnosis experiments are designed to demonstrate the superiority of the method based on a self-made dataset and the publicly available rolling bearings dataset. The experimental results show that the proposed method can achieve higher fault diagnosis accuracy and better robustness under cross-conditions than the contrasting methods.
Quantum vacuum processes in the extremely intense light of relativistic plasma mirror sources
Authors: Sainte-Marie Antonin , Fedeli Luca , Zaïm Neïl , Karbstein Felix , Vincenti Henri
Published: May 2022

The advent of petawatt-class laser systems allows generating electromagnetic fields of unprecedented strength in a controlled environment, driving increasingly more efforts to probe yet unobserved processes through their interaction with the quantum vacuum. Still, the lowest intensity scale governing these effects lies orders of magnitude beyond foreseen capabilities, so that such endeavor is expected to remain extremely challenging. In recent years, however, plasma mirrors have emerged as a promising bridge across this gap, by enabling the conversion of intense infrared laser pulses into coherently focused Doppler harmonic beams lying in the X-UV range. In this work, we present predictions on the quantum vacuum signatures produced when such beams are focused to intensities between 1024 and 1028 W cm−2, specifically photon–photon scattering and electron–positron pair creation. These signatures are computed via the stimulated vacuum formalism, combined with a model of perfectly focused beam built from PIC-generated harmonics spectra, and implemented on state-of-the-art massively parallel numerical tools. In view of identifying experimentally favorable configurations, we also consider the coupling of the focused harmonic beam with an auxiliary optical beam, and provide comparison with other established schemes. Our results show that a single coherently focused harmonic beam can produce as much scattered photons as two infrared pulses in head-on collision, and confirm that the coupling of the harmonic beam to an auxiliary beam gives rise to significant levels of inelastic scattering, and hence holds the potential to strongly improve the attainable signal to noise ratios in experiments.
Nature of particles azimuthal anisotropy at low and high transverse momenta in ultrarelativistic A + A collisions
Authors: Bravina L V , Eyyubova G Kh , Korotkikh V L , Lokhtin I P , Petrushanko S V , Snigirev A M , Zabrodin E E
Published: May 2022

LHC data on the correlations of the elliptic flow v
2 of particles at low and high transverse momenta p

T
from Pb+Pb collisions at center-of-mass energy per nucleon pair

s

NN

=
5.02

TeV are analyzed in the framework of the HYDJET++ model. This model includes soft and hard components which allows to describe the region of both low and high transverse momenta. The origin of v
2 values in different p

T
regions is investigated at different centralities. It is shown that the experimentally observed correlations between v
2 at low and high p

T
in peripheral lead-lead collisions is due to correlation of particles in jets.
Stability of motion and thermodynamics in charged black holes in f(T) gravity
Authors: Nashed G.G.L. , Saridakis Emmanuel N.
Published: May 2022

We investigate the stability of motion and the thermodynamics in the
case of spherically symmetric
solutions in f(T) gravity using the perturbative approach. We
consider small deviations from general relativity
and we extract charged black hole solutions for two charge profiles, namely
with or without a perturbative correction in the charge distribution.
We examine their asymptotic behavior, we extract various torsional and
curvature invariants, and we calculate the energy and the mass of the
solutions. Furthermore, we study the stability of motion around the
obtained solutions, by analyzing the geodesic
deviation, and we extract the unstable regimes in
the parameter space. We calculate the inner
(Cauchy) and outer (event) horizons, showing that for larger deviations from
general relativity or larger charges, the horizon disappears and the central
singularity becomes a naked one. Additionally, we perform a detailed thermodynamic
analysis examining the temperature, entropy, heat capacity and Gibb's free
energy. Concerning the heat capacity we find that for larger deviations from
general relativity it is always positive, and this
shows that f(T) modifications improve the thermodynamic stability, which
is not the case in other classes of modified gravity.
Relativistic calculations on the transition electric dipole moments and radiative lifetimes of the spin-forbidden transitions in the antimony hydride molecule
Authors: Liu Yong , Li Lu-Lu , Xiao Li-Dan , Yan Bing
Published: May 2022

Calculations on the spectroscopic constants and transition properties of the first three states (a1Δ, b1Σ+, and X3Σ−) of the SbH molecule were performed under the relativistic framework using the exact two-component Hamiltonian (X2C). The potential energy curves in the Franck–Condon region were computed and compared with the previous values. Furthermore, the transition dipole moments for the weak spin-forbidden transitions (b0+–X10+, b0+–X21, X10+–X21, and X21–a2) were reported. The spontaneous radiative lifetime of the b1Σ+ (υ′ = 0) state was calculated as 163.5±7.5 μ s, which is in reasonable agreement with the latest experimental value of 173±3 μ s. The spontaneous radiative lifetimes of the X21 (υ′ = 0) state and the a2 (υ′ = 0) state were calculated to be 48.6 s and ∼ 8 ms, respectively. Our study is expected to be a benchmark transition property computation for comparison with other theoretical and experimental results. The datasets presented in this paper, including the transition dipole moments, are openly available at https://dx.doi.org/10.11922/sciencedb.j00113.00018.
Accurate determination of anisotropic thermal conductivity for ultrathin composite film
Authors: Zhu Qiu-Hao , Peng Jing-Song , Guo Xiao , Zhang Ru-Xuan , Jiang Lei , Cheng Qun-Feng , Liang Wen-Jie
Published: May 2022

Highly anisotropic thermal conductive materials are of significance in thermal management applications. However, accurate determination of ultrathin composite thermal properties is a daunting task due to the tiny thermal conductance, severely hindering the further exploration of novel efficient thermal management materials, especially for size-confined environments. In this work, by utilizing a hybrid measuring method, we demonstrate an accurate determination of thermal properties for montmorillonite/reduced graphene oxide (MMT/rGO) composite film with a thickness range from 0.2 μm to 2 μm. The in-plane thermal conductivity measurement is realized by one-dimensional (1D) steady-state heat conduction approach while the cross-plane one is achieved via a modified 3ω method. As-measured thermal conductivity results are cross-checked with different methods and known materials, revealing the high measurement accuracy. A high anisotropic ratio of 60.5, independent of composite thickness, is observed in our measurements, further ensuring the negligible measurement error. Notably, our work develops an effective approach to the determination of ultrathin composite thermal conductivity, which may promote the development of ultrathin composites for potential thermal-related applications.
Magnetic van der Waals materials: Synthesis, structure, magnetism, and their potential applications
Authors: Lin Zhongchong , Peng Yuxuan , Wu Baochun , Wang Changsheng , Luo Zhaochu , Yang Jinbo
Published: May 2022

As the family of magnetic materials is rapidly growing, two-dimensional (2D) van der Waals (vdW) magnets have attracted increasing attention as a platform to explore fundamental physical problems of magnetism and their potential applications. This paper reviews the recent progress on emergent vdW magnetic compounds and their potential applications in devices. First, we summarize the current vdW magnetic materials and their synthetic methods. Then, we focus on their structure and the modulation of magnetic properties by analyzing the representative vdW magnetic materials with different magnetic structures. In addition, we pay attention to the heterostructures of vdW magnetic materials, which are expected to produce revolutionary applications of magnetism-related devices. To motivate the researchers in this area, we finally provide the challenges and outlook on 2D vdW magnetism.
Hidden-charm pentaquark states through current algebra: from their production to decay *
Authors: Chen Hua-Xing
Published: May 2022

There may be seven

hadronic molecular states. We construct their corresponding interpolating currents and calculate their masses and decay constants using QCD sum rules. Based on these results, we calculate their relative production rates in

decays using current algebra, that is,

, where

and

are two different states. We also study their decay properties via Fierz rearrangement and further calculate these ratios in the

mass spectrum, that is,

. Our results suggest that the

molecular states of

and

may be observed in future experiments.
On the Rotation Properties of a Post-explosion Helium-star Companion in Type Iax Supernovae
Authors: Zeng Yaotian , Liu Zheng-Wei , Meng Xiangcun , Han Zhanwen
Published: May 2022

Recent studies have suggested that type Iax supernovae (SNe Iax) are likely to result from a weak deflagration explosion of a Chandrasekhar-mass white dwarf in a binary system with a helium (He)-star companion. Assuming that most SNe Iax are produced from this scenario, in this work we extend our previous work on the three-dimensional hydrodynamical simulation of ejecta-companion interaction by taking the orbital and spin velocities of the progenitor system into account. We then follow the post-impact evolution of a surviving He-star companion by using the one-dimensional stellar evolution code MESA. We aim to investigate the post-explosion rotation properties of a He-star companion in SNe Iax. We find that the He-star companion spins down after the impact due to the angular-momentum loss and expansion caused by the mass-stripping and shock heating during the interaction. This leads to the situation where the surface rotational speed of the surviving companion can drop to one-third of its pre-explosion value when it expands to a maximum radius a few years after the impact. Subsequently, the star shrinks and spins up again once the deposited energy is released. This spin-switching feature of the surviving He-star companions of SNe Iax may be useful for the identification of such objects in future observations.
The Role of Magnetic Fields in Triggered Star Formation of RCW 120
Authors: Chen Zhiwei , Sefako Ramotholo , Yang Yang , Jiang Zhibo , Yu Shuling , Yin Jia
Published: May 2022

We report on the near-infrared polarimetric observations of RCW 120 with the 1.4 m IRSF telescope. The starlight polarization of the background stars reveals for the first time the magnetic field of RCW 120. The global magnetic field of RCW 120 is along the direction of 20°, parallel to the Galactic plane. The field strength on the plane of the sky is 100 ± 26 μG. The magnetic field around the eastern shell shows evidence of compression by the H ii region. The external pressure (turbulent pressure + magnetic pressure) and the gas density of the ambient cloud are minimum along the direction where RCW 120 breaks out, which explains the observed elongation of RCW 120. The dynamical age of RCW 120, depending on the magnetic field strength, is ∼1.6 Myr for field strength of 100 μG, older than the hydrodynamic estimates. In direction perpendicular to the magnetic field, the density contrast of the western shell is greatly reduced by the strong magnetic field. The strong magnetic field in general reduces the efficiency of triggered star formation, in comparison with the hydrodynamic estimates. Triggered star formation via the “collect and collapse” mechanism could occur in the direction along the magnetic field. Core formation efficiency (CFE) is found to be higher in the southern and eastern shells of RCW 120 than in the infrared dark cloud receiving little influence from the H ii region, suggesting increase in the CFE related to triggering from ionization feedback.
Toward learning dynamic origin-destination matrices from crowd density heatmaps
Authors: Gödel Marion , Lehmberg Daniel , Brydon Rebecca , Bosina Ernst , Köster Gerta
Published: May 2022

Knowing the origins and destinations of pedestrians’ paths is key to the initialization of crowd simulations. Unfortunately, they are difficult to measure in the real world. This is one major challenge for live predictions during events such as festivals, soccer games, protest marches, and many others. Sensor data can be used to feed real-world observations into simulations in real-time. As input data for this study, we use density heatmaps generated from real-world trajectory data obtained from stereo sensors. Density information is compact, of constant size, and in general easier to obtain than e.g., individual trajectories. Therefore, the information limitation improves the applicability to other scenarios. We include the absolute pedestrian trip counts from origins to destinations during a brief time interval in an OD matrix, including unknown destinations due to sensor errors. Our goal is to estimate these OD matrices from a series of density heatmaps for the same interval. For this, we compute the ground truth OD matrices and density heatmaps using real-world trajectory data from a train station. We employ linear regression as a statistical learning method for estimation. We observe that the linear share of the relationship between density and OD matrix is estimated successfully. Nevertheless, a portion of the data remains that cannot be explained. We attempt to overcome this difficulty with random forest as a nonlinear model. The results indicate that both a linear and a nonlinear model can estimate some features of the OD matrices. However, there is no clear winner in terms of the chosen metric, the R
2 score. Overall, our findings are a strong indicator that OD matrices can indeed be estimated from density heatmaps extracted automatically from sensors.
Phase transition for the Ising model with mixed spins on a Cayley tree
Authors: Akin Hasan , Mukhamedov Farrukh
Published: May 2022

In the present paper, we consider the Ising model with mixed spin- (1, 1/2) on the second order Cayley tree. For this model, a construction of splitting Gibbs measures is given that allows us to establish the existence of the phase transition (non-uniqueness of Gibbs measures). We point out that, in the phase transition region, the considered model exhibits three translation-invariant Gibbs measures in the ferromagnetic and anti-ferromagnetic regimes, respectively, while the classical Ising model does not possess such Gibbs measures in the anti-ferromagnetic setting. It turns out, that like the classical Ising model, we can find a disordered Gibbs measure, therefore, its non-extremity and extremity are investigated by means of tree-indexed Markov chains.
Research on consistency control of angular velocity of UAV swarm
Authors: Pang Qiangwei , Chen Ye , Wu Zhonghong , Zhu Yongyong , Li Zongji
Published: May 2022

In order to keep the angular velocity output of unmanned aerial vehicle (UAV) swarm consistent, a solution is proposed in this paper. Firstly, a reasonable simplified modeling is carried out for UAV, and its linear part is selected to set the output consistency controller. Then, based on graph theory and lyapunov stability theorem, the asymptotic stability conditions of the designed controller are given. Finally, the effectiveness of the proposed method is verified by simulation. The results show that the designed controller can quickly keep the output angular velocity of UAV swarm consistent.
Comparative study of 3D object detection frameworks based on LiDAR data and sensor fusion techniques
Authors: Venugopala Sreenivasa Hikkal
Published: May 2022

Estimating and understanding the surroundings of the vehicle precisely forms the basic and crucial step for the autonomous vehicle. The perception system plays a significant role in providing an accurate interpretation of a vehicle’s environment in real-time. Generally, the perception system involves various subsystems such as localization, obstacle (static and dynamic) detection, and avoidance, mapping systems, and others. For perceiving the environment, these vehicles will be equipped with various exteroceptive (both passive and active) sensors in particular cameras, Radars, LiDARs, and others. These systems are equipped with deep learning techniques that transform the huge amount of data from the sensors into semantic information on which the object detection and localization tasks are performed. For numerous driving tasks, to provide accurate results, the location and depth information of a particular object is necessary. 3D object detection methods, by utilizing the additional pose data from the sensors such as LiDARs, stereo cameras, provides information on the size and location of the object. Based on recent research, 3D object detection frameworks performing object detection and localization on LiDAR data and sensor fusion techniques show significant improvement in their performance. In this work, a comparative study of the effect of using LiDAR data for object detection frameworks and the performance improvement seen by using sensor fusion techniques are performed. Along with discussing various state-of-the-art methods in both the cases, performing experimental analysis, and providing future research directions.
Simulation design of reliability improvement of metal hose for rocket engine
Authors: Kun Chen Chong , Yan Liu , Jun Wang Zhao , Fang Zhao Ji , Meng Wang
Published: May 2022

Facing the new challenges of high-density space launches in the later period, this paper studies the numerical simulation of the metal hose used in the new generation of launch vehicle models to improve the reliability of the metal hose. Through the calculation of bellows with different elements, it is found that the calculation results of shell element and solid element are similar, and the calculation efficiency of shell element is much higher than that of solid element. Finally, it is established that the SHELL181 is used for the finite element calculation of the bellows. Based on the stiffness equivalent theory, an equivalent model of the net sleeve with strands as the unit is established. Through the verification of finite element and experiment, this equivalent model can better simulate the linear stage of metal mesh sleeve under tension. Finally, the modeling method of metal hose simulation design is established.
Microstructure and properties of Cu-Cr-Ti alloy with high softening resistance
Authors: Yang Zhen , Wang Wanyu , Ma Jimiao , Liu Xingyu , Liu Feng
Published: May 2022

Cu-Cr alloys with excellent mechanical and electrical properties have been used in many industrial fields. However, the weak heat resistance of Cu-Cr alloys is a considerable shortness. In this work, Cu-Cr-Ti alloy was fabricated by vacuum melting and plastic deformation. Mechanical property and electrical conductivity of Cu-Cr-Ti alloy were investigated after aging treatment. The results show that peak aging occurs when aging at 450 °C for 1 hour. The mechanism of performance changes are discussed. The softening temperature could be identified as 575 °C, according to percentage of hardness changes of peak-aged Cu-Cr-Ti alloy annealed at different temperature and time. The microstructure explained that the addition of Ti, which retards recrystallization, could enhance the softening resistance of Cu-Cr alloy.
Sample preparation and research of amorphous composite material for transmission electron microscope
Authors: Zhu Y. J. , Jiang R. , Zhang Z. W. , Zhao J. , Chen Y. , Li Y. L. , Ding B. Y.
Published: May 2022

The two preparation methods of amorphous composite TEM samples, electrolytic double spray thinning and ion thinning, are studied. In addition, an improved ion thinning method is used to successfully prepare a metastable brittle amorphous composite TEM sample. The TEM sample prepared by the ion thinning method has a large thin area near the interfaces in composites, which lays a solid foundation for further research on the interface principle of composite materials, and also provides reliable data support for optimizing the preparation process of the composite materials.
Performance analysis of FeCoCr1.5NiAl high-entropy alloy coating on H13 steel by laser cladding
Authors: Gao Y. L. , Kou G. P.
Published: May 2022

For a better performance of the high wear resistance of H13 die steel, FeCoCr1.5NiAl High Entropy Alloy coating was prepared on H13 by laser cladding. The results show that the HEA coating has good metallurgical bonding with matrix. The microstructure of coating is columnar crystal and equiaxed crystal. The coating has the single-phase body-centered cubic and face-centered cubic. The microhardness of this coating is up to 800HV, about 4 times that of the matrix. The friction coefficient of coating is smaller than matrix and the wear volume of coating is decreased approximately 61.02% compared with matrix. The main wear forms of coating is abrasive wear and wear forms of matrix is abrasive wear and fatigue wear.
In vitro hydrolytic degradation properties of poly(D, L-lactic acid) / poly(L-lactide-co-ε-caprolactone) blend films
Authors: Deng Dongwen , Li Mingxi , Li Fengqin , Wu Gensheng , Zhang Yi , Ni Zhonghua , Zhao Gutian
Published: May 2022

Biodegradable materials are widely used in biomedical application. Blending polymers have become a promising strategy to regulate degradation rate and expand material properties. In this study, the poly(D, L-lactic acid) (PDLLA) and polyCL-lactide-co-ɛ-caprolactone) (PLcCL) blend films with different ratios were prepared by the ultrasonic spray technology and the in vitro hydrolytic degradation tests of these films were then carried out in phosphate buffered saline with 37°C and 50°C. The in vitro degradation of the blend films were investigated via mass loss, gel permeation chromatography (GPC), scanning electron microscopy (SEM). It was found that the blended film had good miscibility and uniformity through SEM tests. Besides, the 50/50 PLcCL/PDLLA film showed the slowest degradation rate at 37°C, while at 50°C, the 100 PLcCL film had the slowest degradation. This work can provide helpful suggestions for the evaluation of biodegradable polymer coating materials in degradable polymer coated stent.
Production of highly dispersed powders of metal-oxides by evaporation-condensation technique when heated by focused radiation of terahertz-range gyrotron setup
Authors: Tsvetkov Alexander , Vodopyanov Alexander , Mansfeld Dmitry , Orlovskiy Alexey , Kamenskiy Maxim , Samokhin Andrey , Alexeev Nikolay , Sinayskiy Mikhail , Sedov Anton
Published: May 2022

The paper describes the experimental setup and some results of experiments on the production of highly dispersed metal oxides powders using the example of tungsten trioxide WO3 by the evaporation-condensation method when the initial material is heated by focused radiation of 0.53 THz / 240 W gyrotron. By focusing the gyrotron radiation, it was possible to achieve an intensity of several kW/cm2 on the surface of the evaporated initial sample. The use of a system with a rotating crucible made it possible to increase the evaporation rate of the substance by 3–4 times, which is very important in conditions of a lack of power.
IGBT Energy Losses Analysis and Heat Dissipation System Design of Three-level Inverter
Authors: Qi Liang , Wang Xu , Pan Jiake
Published: May 2022

According to the needs of the design and development of three-level inverter, the paper introduces the design process of the inverter cooling system in detail. Firstly, this paper proposes a calculation method of the energy losses in the insulated gate bipolar transistor(IGBT) and freewheeling diode(FWD), and calculates the energy losses of the IGBT module in the inverter according to the method. Otherwise, a set of the inverter forced air cooling heat dissipation system is designed, and the simulation of the finite element analysis is used for the analysis and optimization of the system. Finally, the test shows that the temperature rise of the IGBT module is within the reasonable range, which verifies the availability and feasibility of the proposed method and the designed system.
Design of power measurement vector analysis tool
Authors: Zhang Shuo , Yi Yongfei , Sun Mengxin , Liu Jinsong , Liu Yang
Published: May 2022

At present, in terms of power marketing measurement training, there are problems such as measurement wiring discrimination inconvenience, drawing inconvenience, wiring display time consuming, resulting in the measurement wiring training is not in place. The article first of the three phase three line power meter and three phase four line power meter correct wiring mode and phasor diagram, and then a special tool for the vector analysis used in the training is designed, which can not only solve the above problems, but also replace the manual drawing of the vector map, which has a good practical effect on the power marketing measurement training, enables the students to learn the measurement wiring more intuitively.
A novel model to identify the performance of power cable on the offshore network by considering dynamic environmental impact
Authors: You Fei , Abdul Talib Mat Yusoh Mohd
Published: May 2022

Shore power cable is an important power equipment for ship-shore interactive transmission. The insulation aging speed of shore power cable is faster than that of ordinary cable, and the application life of the shore power cable is relatively short. Therefore, this paper is based on multi physical field coupling on the shore power cable under special conditions incorporating all environment impact, to analyze the impact of solar radiation on the temperature distribution of multi-loop shore power cable, and to propose a novel technique to calculate realtime ampacity of shore power cable based on the heat balanced equation, so a novel model to identify the performance of power cable on the offshore network by considering dynamic environmental impact is established.
Short-circuit fault evaluation of SF6 circuit breaker energy storage motor coil based on high-frequency equivalent model
Authors: Qian Shuaiwei , Wang Lu , Peng Yanjun , Huang Yongqiang , Sun Chunshu , Jiang Wei , Zhou Xiong
Published: May 2022

The capacitive inductance parameters of the energy storage motor windings were calculated by finite element method, and the high-frequency equivalent model of the winding was established based on ATP-EMTP. Square wave pulse voltage signal was applied to the input end of the model, and the response voltage curve at the end of the circuit model was measured. The wavelet packet-energy spectrum was calculated as the characteristic parameter of the response curve in different short-circuit positions, and the short-circuit position was evaluated by the random forest algorithm. The accuracy rate of short-circuit fault location in the test set was 75%, indicating that the method has certain feasibility.
Mathematical Model and Performance Analysis of Aluminum Tube Collector
Authors: Yan Xiao , Zhang XiaoMing , Wei YiLi
Published: May 2022

Aluminum tube collector is a new type of collector that can be popularized, which can absorb solar energy and air energy at the same time. By analyzing the heat transfer process of aluminum tube collector, its mathematical model is established, and iterative calculation is carried out in Visual Basic to obtain the relationship between collector efficiency and different parameters. Finally, it is concluded that the thermal efficiency of aluminum tube collector is about 1.5, which is much higher than that of traditional collector; In sunny days with high ambient temperature, aluminum tube collectors are preferred; When the fin width is about 28mm, the mass flow is 0.20kg/s-0.25kg/s, and the inlet temperature of the working medium of the collector is about 5-10°C lower than the ambient temperature, the performance of the collector is better.
Construction and implementation of power grid dispatching interactive system based on Internet
Authors: Qi Xuesong , Tian Li , Sun Jia , Li Mengqi
Published: May 2022

The construction of the information-based and intelligent platform can completely reform the management mode of enterprises, effectively improve the production efficiency and competitive strength of enterprises. In view of the importance of information and intelligence construction, domestic electric power enterprises continuously build and transform information platform based on their own business needs. In this paper, starting from the background of the construction of the Power Grid Dispatching Command Network Interactive System, the dispatching standard and the overall idea of systems engineering, the interactive mode and system structure scheme of the power grid dispatching command network based on the national and industry standards are proposed, based on the computer network, the interactive supporting mode of dispatching command network is constructed to form a comprehensive and efficient dispatching command network, which ensures the flexibility and reliability of dispatching command interaction and improves the level of dispatching command.
Stability analysis and Simulation of power system based on Matlab
Authors: Wu Junda , Jing Gao , Yi Zhao
Published: May 2022

Abstact: The stability analysis of power system is an important process to measure the security and stability level of the power system and the construction and development plan. The stability of the power system is divided into static stability, transient stability and dynamic stability. The stability of the system is judged by different analysis methods for different forms and sizes of interference. The construction of large power grid is developing rapidly, and the powerful computing function of Matlab can adapt to the more and more huge power system stability calculation tasks. As a Matlab sub module, Simulink can properly assist the stability calculation of power system with its powerful and stable computing function and simple visual modular graphics.

In this paper, the concept of power system stability is first proposed, the static stability and transient stability of power system are briefly introduced. Secondly, the static / transient stability of power system is simulated with Simulink, and the measures to improve the static / transient stability of power system are proposed.
Power Monitoring System Based on 4G Network Wireless Transmission
Authors: Liu Xiaohong , Li Donghua , Xun Sichao , Zhang Guomin , Xu Feng , Zhao Yiyi
Published: May 2022

In order to solve the problems faced by high-voltage power facilities in the monitoring process, after comprehensively considering the characteristics of high-voltage transmission lines, regional environment, and other factors, a data monitoring system based on the perception layer of the Internet of Things is established. The system uses advanced IoT(Internet of Things) sensing technology, networking technology, and transmission technology to network data sub-nodes such as tower settlement, line galloping, and meteorology for information transmission. After the transmitted sensor information is fused and further processed, the overall judgment and early warning of the disaster area are formed.
The JUNO experiment and its electronics readout system
Authors: Petitjean P.-A. , Clerbaux B. , Collomer Molla M. , Yang Y.
Published: May 2022

The main goal of the Jiangmen Underground Neutrino Observatory (JUNO) under construction in China is to determine the neutrino mass hierarchy and to measure oscillation parameters to the sub-percent level. The detector consists of 20 ktons of liquid scintillator instrumented by 17612 20-inch photo-multiplier tubes, and 25600 3-inch small PMTs, with photo-cathode coverage of 77%. The electronics system is separated into two main parts. The front-end system, sitting under water, performs analog signal processing. The back-end electronics system, sitting outside water, consists of the DAQ and the trigger. The current production status of the experiment as well as the design of the electronics system will be reported in the presentation.
BBM92 quantum key distribution over a free space dusty channel of 200 meters
Authors: Mishra Sarika , Biswas Ayan , Patil Satyajeet , Chandravanshi Pooja , Mongia Vardaan , Sharma Tanya , Rani Anju , Prabhakar Shashi , Ramachandran S , Singh Ravindra P
Published: May 2022

Free-space quantum communication assumes importance as it is a precursor for satellite-based quantum communication needed for secure key distribution over longer distances. Prepare and measure quantum key distribution (QKD) protocols like BB84 consider the satellite as a trusted device, which is fraught with security threat looking at the current trend for satellite-based optical communication. Therefore, entanglement-based protocols must be preferred, so that one can consider the satellite as an untrusted device. The current work reports the effect of atmospheric aerosols on the key rate obtained with BBM92 QKD protocol, an entanglement-based QKD protocol over 200 m distance, using an indigenous facility developed at Physical Research Laboratory (PRL), Ahmedabad, India. Our results show that concentration and extinction coefficient of atmospheric aerosols play a major role in influencing the observed sift key rate, and eventually, the secure key rate. Such experiments are important to validate the models to account for the atmospheric effects on the key rates achieved through satellite-based QKD.
Comparative study of green synthesised sulphur nanoparticles in different acidic media
Authors: Himanshi  , Joshi Deepika P
Published: May 2022

Sulphur nanoparticles (SNPs) are of great importance, due to their tremendous use in agriculture and industries. In the present work, a comparative study has been conducted to find the most suitable combination to produce desired sulphur nanoparticles, using different acidic mediums along with different green surfactants. An eco-friendly and benign method has been discussed here for the synthesis of SNPs using two different acidic mediums (citric acid and oxalic acid). Catharanthus roseus and Aloevera plant extracts have been taken as stabilising and capping agents in the process. A series of characterisation techniques have been carried out such as scanning electron microscopy (SEM), x-ray diffraction (XRD), Fourier transform-infrared spectroscopy (FTIR) and UV–vis for morphological, structural and optical study. UV–vis absorption spectra have shown that the absorption peak is in the range of 287−296 nm for all the synthesised nanoparticles and confirm the formation of SNPs. XRD data has revealed the crystalline nature of SNPs and the smallest crystalline size of 69 nm for oxalic acid with Aloevera leaf extract. It has been observed that the size reduces due to the bonding/ adsorption of biomolecules at the surface of SNPs. Aloevera leaf extract gives the maximum adsorption as conveyed by the FTIR graph. The morphology and uniformity of SNPs are observed using the scanning electron microscope. SNPs synthesised using citric acid as a reducing agent have been found spherical in shape while the ones synthesised using oxalic acid are hexagonal. The study reveals that the SNPs synthesised using Aloevera and oxalic acid are more uniform and monodispersed.
Light emission properties of mechanical exfoliation induced extended defects in hexagonal boron nitride flakes
Authors: Ciampalini G , Blaga C V , Tappy N , Pezzini S , Watanabe K , Taniguchi T , Bianco F , Roddaro S , Fontcuberta I Morral A , Fabbri F
Published: May 2022

Recently, hexagonal boron nitride (hBN) has become an interesting platform for quantum optics due to its peculiar defect-related luminescence properties. Concomitantly, hBN was established as the ideal insulating support for realizing 2D materials devices, where, on the contrary, defects can affect the device performance. In this work, we study the light emission properties of hBN flakes obtained by mechanical exfoliation with particular focus on extended defects generated in the process. In particular, we tackle different issues related to the light emission in hBN flakes of different thicknesses in the range of hundreds of nanometers, revealing a higher concentration of deep level emission in thinner area of the flake. We recognize the effect of crystal deformation in some areas of the flake with an important blue-shift (130 meV) of the room temperature near band edge emission of hBN and the concurrent presence of a novel emission at 2.36 eV, related to the formation of array of dislocations. We studied the light emission properties by means of cathodoluminescence (CL) and sub-bandgap excitation photoluminescence of thickness steps with different crystallographic orientations, revealing the presence of different concentration of radiative centers. CL mapping allows to detect buried thickness steps, invisible to the scanning electron microscopy and atomic force microscopy morphological analysis.