bluuebunny/crossref_metadata_2025_split huggingface dataset:
Nonequilibrium shock layer in large-scale arc-heated wind tunnel
Authors: Takahashi Yusuke , Takasawa Hideto , Yamada Kazuhiko , Shimoda Takayuki 
Published: March 2022

Abstract
An arc-heated wind tunnel is one of the most important facilities to reproduce the high-temperature environment during atmospheric entry for plasma studies and spacecraft development. However, the properties of the plasma flow cannot be determined easily, because of the complex physical phenomena, such as arc discharge and supersonic expansion, occurring inside the tunnel. The shock-layer structure should be clarified to evaluate the aerodynamic characteristics, communication conditions, and thermal-protection performance in a high-temperature environment. In this study, shock-layer spectroscopic measurements of a plasma flow in a 1 MW-class arc-heated wind tunnel were performed. The γ-band system spectra of nitric oxide (

NO

) molecules in the ultraviolet region were measured, and the rotational temperature was determined via spectral fitting through comparison with numerical spectra. The rotational temperature of the

NO

molecules in the shock layer was 6620 ± 350 K, whereas that in the free jet was much lower at 770 ± 60 K. This difference is attributed to the increase in translational temperature by flow stagnation across the shock wave, followed by the increase in rotational temperature owing to energy relaxation. A computational science approach revealed the detailed structure of the flow through comparisons with the spectroscopic measurement data. The wind tunnel flow became hypersonic with high temperature and low pressure due to the expansion and acceleration at the nozzle and test chamber. Although the temperature increased across the shock wave, the chemical reaction progressed slowly owing to the low-pressure environment. The rotational temperature in the shock layer increased with the translational temperature; this agrees with the trend of the measurement results. The arc-heated flow was found to be in strong thermochemical nonequilibrium in the shock layer. Through this study, a detailed structure of arc-heated flow was revealed and its methodology was also proposed.
Thickness-dependence of magnetic damping related to two-magnon scattering in ultrathin Ni0.81Fe0.19 films
Authors: Li Yaojin , Li Chunlei , Du Qin , Shi Keqing , Zhou Ziyao , Liu Ming , Pan Jingye 
Published: March 2022

Abstract
Magnetic damping is of critical importance for devices due to its influences on magnetization dynamics. When the ferromagnetic layer goes into the nanometer scale, the magnetic damping related to the two-magnon scattering (TMS) effect becomes the main damping in nonmagnetic/ferromagnetic films. Here, we experimentally demonstrated the thickness-dependence of TMS damping, one part dependent on ferromagnetic thickness (

t

F
M

), another part independent, in both Cu/NiFe and Pt/NiFe films. The

t

F
M

−
2

scale of TMS damping can be explained based on the ‘Arias–Mills’ mode, and its origin is the distribution of surface magnetic anisotropy due to interface defects. The rest of TMS damping is independent on

t

F
M

is attributed to the more generic defects creating inhomogeneity, and its origin can be sorted into the ‘McMichael–Krivosik’ mechanism. The quantitative results reveal that the

t

F
M

−
2

-dependent and

t

F
M

-independent TMS damping are of equal importance in ultrathin NiFe films. Meanwhile, the approximately equal intrinsic damping was displayed for Cu/NiFe and Pt/NiFe thin films. Our results add a clearer understanding of TMS damping in ultrathin ferromagnetic films.
Tight-binding studies of uniaxial strain in T-graphene nanoribbons
Authors: Hopkinson J , Hancock Y 
Published: March 2022

Abstract
The role of uniaxial strain in armchair, T-graphene nanoribbons (ATGNRs) with symmetric and asymmetric structures is investigated using a nearest-neighbour, tight-binding (TB) model. ATGNRs with structural symmetry and two a sub-lattice structure exhibit Dirac points at zero strain. Application of uniaxial strain to these systems induces multiple Dirac points under compression (up to −20% strain), with the number of these points commensurate with the number of tetra-carbon base-units along the width of the unit cell, accounting also for the mirror symmetry of the structure. Under tensile, uniaxial strain (up to 20% extension), the induced asymmetry in the carbon tetrabond results in the number of Dirac points being reduced, although a minimum number are preserved due to the fundamental mirror-symmetry of the symmetric ATGNR. Asymmetric ATGNRs, which are semiconductors, are shown to have tunable band-gaps that decrease as a function of increasing ribbon width and uniaxial strain. Uniaxial strain induces a single Dirac point at the band edge of these systems under high compression (

>

16%), with the closing of the band gap linked to symmetry-induced perturbations in the structure that override the symmetry-breaking, gap-opening mechanisms. In summary, the TB model shows ATGNRs to have suitable device features for flexible electronics applications, such as band-gap tuning, and for the strain engineering of relativistic properties.
Hard-templated engineering of versatile 2D amorphous metal oxide nanosheets
Authors: Chang Ling , Feng Wei , Xia Yan , Jiang Qvzi , Dong Angang , Chen Yu 
Published: March 2022

Abstract
Two-dimensional (2D) nanomaterials have received ever-increasing attention and in-depth exploration in multifarious fields on account of their superior mass transfer ability and abundant catalytic-active sites. Especially, the amorphous 2D nanomaterials feature unique properties distinct from atomic crystalline materials. However, the synthesis of high-quality and large-sized amorphous 2D nanomaterials encounters a big challenge. Here, a general and facile synthetic strategy for a series of 2D amorphous metal and nonmetallic oxides nanosheets, including SiO2, AlOOH, ZrO2 and TiO2 nanosheets, is reported. The versatile 2D amorphous nanomaterials are fabricated via manipulating the surface energy of relevant metal alkoxide precursors with liquid feature and controlling the related synthesis parameters to form solid 2D amorphous nanosheets by in situ hydrolysis and condensation of precursors. Density functional theory (DFT) calculations reveal the molecular adsorption mechanism of wetting process of precursor infiltrated on solid NaCl substrate, which attributes to the strong interaction between Na–O atom pairs from NaCl and metal alkoxides respectively. Furthermore, taking the 2D Fe–ZrO2 nanomaterials as the catalyst, the excellent catalytic performance for Rhodamine B (RhB) degradation illustrates that these 2D nanomaterials prepared by this method have the characteristics of easy functionalization. This work provides an efficient strategy for nanomaterials functionalization during 2D nanosheets synthetic process and further being applied in catalysis-related field and beyond.
Experimental investigation of electromagnetic GAMs under the influence of 3D magnetic topological structure in EAST
Authors: Qu H , Kong D F , Xu M , Liu A D , Liang Y F , Zhang S B , Cai H S , Qiu Z Y , Chen W , Shi T H , Gu S , Duan Y M , Wang H H , Chu N , Zhao H L , Xiang H M , Wang Y M , Han X , Zhang T , Gao X , Feng X , Zhou C , Zhuang G , Hu L Q , Xu G S , Gong X Z 
Published: March 2022

Abstract
The relationship between geodesic acoustic modes (GAMs) and tearing modes (TMs), or locked modes (LMs), have been investigated in EAST. Firstly, multi-branch electromagnetic GAMs are observed synchronously after the excitation of TMs. Broadened radial coverage is observed for these branches, and these frequencies can be described by the dispersion relation of GAM. Secondly, multi-branch electromagnetic GAMs are generated after the excitation of LMs. The toroidal asymmetric structure of GAMs is excited due to the existence of 3D intrinsic error fields, and the radial distribution of those branches is altered accordingly. Four branches of electromagnetic GAMs are observed in the region that is closer to the ‘X’-point of the locked magnetic islands, which should be merged into two branches for the region that is closer to the ‘O’-point, as confirmed by XUV array measurement. Thirdly, a similar phenomenon is reproduced by the modulation of resonant magnetic perturbation (RMP). The frequency of GAM increases with the current of the RMP coils, and multi-branches of similar modes are generated when the current achieves

I

R
M
P

=
2.5

kA, where the electrostatic and electromagnetic components are altered accordingly. The features of those branches are modulated by the rotation of the RMP. Therefore, the structures of the pair of GAMs can be different, which should be influenced by the different magnetic topological structure.
Stacked chalcogenide metasurfaces for third harmonic generation in the UV range
Authors: Vincenti M A , Gao J , de Ceglia D , Frantz J A , Scalora M , Litchinitser N M 
Published: March 2022

Abstract
We show that an appropriately designed chalcogenide metasurface allows the enhancement of harmonic generation in the UV range, a regime that conventional wisdom deems inaccessible because of absorption. Here we exploit a combination of the photonic band structure that forms when stacking As2S3 metasurfaces, phase-locking, nonlinear dispersion, and improved field localization to enhance third harmonic conversion efficiency. We demonstrate an improvement of two orders of magnitude with respect to the single layer counterpart notwithstanding the fact that the harmonic signal is tuned deep in the absorption range at 285 nm.
Atoms in a spin dependent optical potential: ground state topology and magnetization
Authors: Szulim Piotr , Trippenbach Marek , Band Y B , Gajda Mariusz , Brewczyk Mirosław 
Published: March 2022

Abstract
We investigate a Bose–Einstein condensate of F = 187Rb atoms in a 2D spin-dependent optical lattice generated by intersecting laser beams with a superposition of polarizations. For 87Rb the effective interaction of an atom with the electromagnetic field contains scalar and vector (called a fictitious magnetic field, B
fic) potentials. The Rb atoms behave as a quantum rotor (QR) with angular momentum given by the sum of the atomic rotational motion angular momentum and the hyperfine spin. The ground state of the QR is affected upon applying an external magnetic field, B
ext, perpendicular to the plane of QR motion and a sudden change of its topology occurs as the ratio B
ext/B
fic exceeds a critical value. It is shown that the change of topology of the QR ground state is a result of combined action of Zeeman and Einstein–de Haas effects. The first transfers atoms to the largest hyperfine component to polarize the sample along the field as the external magnetic field is increased. The second sweeps spin to rotational angular momentum, modifying the kinetic energy of the atoms.
Efficient color image encryption algorithm based on 2D coupled chaos and multi-objective optimized S-box
Authors: Yang Sen , Tong Xiaojun , Wang Zhu , Zhang Miao 
Published: March 2022

Abstract
In order to ensure the security of the encryption result and increase the speed of the encryption algorithm as much as possible, this paper proposes an efficient color image encryption algorithm based on 2D Sine-Logistic-Gaussian coupled chaos(2D-SLG chaos) and multi-objective optimized S-box. Firstly, this paper designs a 2D-SLG chaos to balance the complexity and computational cost of chaotic behavior. Secondly, this paper uses multi-objective particle swarm optimization to optimize the initial S-box to obtain an S-box with higher and balanced performance to perform the substitution operation. Finally, this paper uses the layer blending method to enhance the mutual influence between layers and uses the idea of linear congruence to generate permutation sequences to perform row and column shift operations. Experimental results show that the proposed encryption algorithm has excellent performance in key space, statistical analysis, key sensitivity, adjacent pixel correlation, differential attack, select plaintext attack and other security tests, and has high robustness and fast encryption speed. Therefore, the algorithm can meet the requirements of reliability and efficiency while ensuring strong security.
Citizen ASAS-SN Data Release. I. Variable Star Classification Using Citizen Science
Authors: Christy C. T. , Jayasinghe T. , Stanek K. Z. , Kochanek C. S. , Way Z. , Prieto J. L. , Shappee B. J. , Holoien T. W.-S. , Thompson T. A. , Schneider A. 
Published: March 2022

Abstract
We present the first results from Citizen ASAS-SN, a citizen science project for the All-Sky Automated Survey for Supernovae (ASAS-SN) hosted on the Zooniverse platform. Citizen ASAS-SN utilizes the newer, deeper, higher cadence ASAS-SN g-band data and tasks volunteers to classify periodic variable star candidates based on their phased light curves. We started from 40,640 new variable candidates from an input list of ∼7.4 million stars with δ < −60° and the volunteers identified 10,420 new discoveries which they classified as 4234 pulsating variables, 3132 rotational variables, 2923 eclipsing binaries, and 131 variables flagged as Unknown. They classified known variable stars with an accuracy of 89% for pulsating variables, 81% for eclipsing binaries, and 49% for rotational variables. We examine user performance, agreement between users, and compare the citizen science classifications with our machine learning classifier updated for the g-band light curves. In general, user activity correlates with higher classification accuracy and higher user agreement. We used the user’s “Junk” classifications to develop an effective machine learning classifier to separate real from false variables, and there is a clear path for using this “Junk” training set to significantly improve our primary machine learning classifier. We also illustrate the value of Citizen ASAS-SN for identifying unusual variables with several examples.
New Modules for the SEDMachine to Remove Contaminations from Cosmic Rays and Non-target Light: byecr and contsep
Authors: Kim Y.-L. , Rigault M. , Neill J. D. , Briday M. , Copin Y. , Lezmy J. , Nicolas N. , Riddle R. , Sharma Y. , Smith M. , Sollerman J. , Walters R. 
Published: March 2022

Abstract
Currently time-domain astronomy can scan the entire sky on a daily basis, discovering thousands of interesting transients every night. Classifying the ever-increasing number of new transients is one of the main challenges for the astronomical community. One solution that addresses this issue is the robotically controlled Spectral Energy Distribution Machine (SEDM) which supports the Zwicky Transient Facility (ZTF). SEDM with its pipeline pysedm demonstrates that real-time robotic spectroscopic classification is feasible. In an effort to improve the quality of the current SEDM data, we present here two new modules, byecr and contsep. The first removes contamination from cosmic rays, and the second removes contamination from non-target light. These new modules are part of the automated pysedm pipeline and fully integrated with the whole process. Employing byecr and contsep modules together automatically extracts more spectra than the current pysedm pipeline. Using SNID classification results, the new modules show an improvement in the classification rate and accuracy of 2.8% and 1.7%, respectively, while the strength of the cross-correlation remains the same. Improvements to the SEDM astrometry would further boost the improvement of the contsep module. This kind of robotic follow-up with a fully automated pipeline has the potential to provide the spectroscopic classifications for the transients discovered by ZTF and also by the Rubin Observatory’s Legacy Survey of Space and Time.
2.56 Gbps CML transceiver for data concentrator ASIC
Authors: Atkin E. , Serazetdinov A. 
Published: March 2022

Abstract
2.56 Gbps CMOS CML-transceiver is presented. The key feature of the design is capability of working with specific inductive load and transmitting data to the remote room about 1 meter away from the experimentation vicinity. Some radiation tolerance techniques used are shown. Testing methodology is briefly described, and concepts in test board realization are provided. The transceiver was designed as an interface part of the data concentrator ASIC, intended for the frontend electronics of the time-projection chamber of the MPD experiment at NICA nuclotron.
Should friction losses be included in an electromechanical model of a bioinspired flapping-wing micro aerial vehicle to estimate the flight energetic requirements?
Authors: Park Moonsoo , Ventikos Yiannis , Abolfathi Ali 
Published: March 2022

Abstract
The paper aims to examine the effects of mechanical losses on the performance of a bioinspired flapping-wing micro aerial vehicle (FWMAV) and ways to mitigate them by introducing a novel electromechanical model. The mathematical model captures the effect of a DC gear motor, slider-crank, flapping-wings aerodynamics, and frictional losses. The aerodynamic loads are obtained using a quasi-steady flow model. The parameters of the flight mechanism are estimated using published experimental data which are also used to validate the mathematical model. Incorporating the flapping mechanism friction losses into the mathematical model enables capturing the physics of the problem with higher accuracy, which is not possible with simpler models. It also makes it possible to estimate the aerodynamic energetic requirements. Moreover, the model enabled evaluations of the effects of adding bioinspired elastic elements on the efficiency of the system. Although it is established through experimental studies that the addition of a bioinspired elastic element can improve system efficiency and increase lift generation, the existing mathematical models fail to model and predict such effects. It has been demonstrated that the addition of an elastic element can reduce friction losses in the system by decreasing the internal forces. Optimised parameters for a FWMAV incorporating elastic elements are also obtained.
Influence of urbanization on hourly extreme precipitation over China
Authors: Huang Xiaowen , Wang Dashan , Ziegler Alan D , Liu Xiaoping , Zeng Hui , Xu Zhibo , Zeng Zhenzhong 
Published: March 2022

Abstract
The impact of rapid urbanization on the spatiotemporal pattern of short-term extreme precipitation in China remains unclear at the subnational scale. In this study, we present a general framework that measures urbanization-induced variation in hourly extreme wet season precipitation (April–October) from 1985 to 2012, with reference to a dynamic urban–rural station classification based on annual changes in urban extent. We found that urbanization in south China (<29° N) brings more extreme precipitation to urban areas than to suburbs, and reduces extreme precipitation continually over urban areas in parts of the north and northeast. Over 60% of provincial capital cities show significant changes in extreme precipitation due to urbanization, including smaller size cities separated from large urban clusters. Urbanization enhances extreme precipitation mainly in the local main part of the rainy season, which refers to May in the south (e.g. urban–rural differences of 0.70 mm h−1 in Guangzhou) and July–September in the central and north (1.16 mm h−1 in August of Beijing). Urbanization also increases hourly extreme precipitation at peak times in diurnal cycles. The results indicate that urbanization has caused overall more and more heterogeneous spatial patterns over China and concentrated distributions during the rainy season and peak time. These patterns warrant attention when assessing the risk of increased waterlogging and flash flooding in urban areas.
Experimental study on surface characteristics in μED milling of Al6063%-5%B4C-5%ZrSiO4 composite using TOPSIS method
Authors: Narasimmalu Ramasubbu , Sundaresan Ramabalan 
Published: March 2022

Abstract
Al6063 composites are widely used in automobile, aerospace and biomedical industries due to their excellent mechanical properties. Machining of micro channels in composites is difficult for conventional machining process due to presence of hard reinforcement. Materials with base metal. Micro Electrical discharge (μED) milling is popular micromachining technique for machining simple, intricate shapes and microchannels on any conductive material. However, it a slow machining process, the identification of optimum condition has become wide research area in μEDM. The present work aims to study the influence of process variables namely voltage, spindle speed and threshold on machining characteristics of μED milling of Hybrid Metal Matrix Composites (HMMCs). Experimental trials are carried out with copper electrode at different parametric condition. Al6063%-5%B4C-5%ZrSiO4 composite was fabricated using stir casting method and experimental runs were designed using general full factorial method. The significant parameters are identified using Analysis of Variance (ANOVA) and the ideal machining conditions for multi-response are determined using Technique for Order of Preference by Similarity to Ideal Solution (TOPSIS) method. The morphology of machined surface with best and worst conditions is examined using SEM. Results indicated that the voltage and threshold are the influencing parameters for considered response indicators. Recast layer thickness seems to be low with best machining conditions as compared to worst conditions. Increase in voltage and threshold increases the Material Removal Rate (MRR) and decreases the Electrode Wear Rate (EWR). Surface finish is better when the lower order of capacitance and voltage is used. MRR is increased by 48% with best machining conditions compared to worst machining condition.
Review of graphene for the generation, manipulation, and detection of electromagnetic fields from microwave to terahertz
Authors: Katzmarek David A , Pradeepkumar Aiswarya , Ziolkowski Richard W , Iacopi Francesca 
Published: March 2022

AbstractGraphene has attracted considerable attention ever since the discovery of its unprecedented properties, including its extraordinary and tunable electronic and optical properties. In particular, applications within the microwave to terahertz frequency spectrum can benefit from graphene’s high electrical conductivity, mechanical flexibility and robustness, transparency, support of surface-plasmon-polaritons, and the possibility of dynamic tunability with direct current to light sources. This review aims to provide an in-depth analysis of current trends, challenges, and prospects within the research areas of generating, manipulating, and detecting electromagnetic fields using graphene-based devices that operate from microwave to terahertz frequencies. The properties of and models describing graphene are reviewed first, notably those of importance to electromagnetic applications. State-of-the-art graphene-based antennas, such as resonant and leaky-wave antennas, are discussed next. A critical evaluation of the performance and limitations within each particular technology is given. Graphene-based metasurfaces and devices used to manipulate electromagnetic fields, e.g. wavefront engineering, are then examined. Lastly, the state-of-the-art of detecting electromagnetic fields using graphene-based devices is discussed.