bluuebunny/crossref_metadata_2025 huggingface dataset:
Field Measurements of Electromagnetic Interference in Hearing Aids
Authors: Levitt Harry , Harkins Judy , Singer Beth , Yeung Eddy
Published: March 2022

This investigation was a preliminary field study to determine the acoustic and perceptual characteristics of hearing aid distortion generated by digital wireless telephones, the usability of the telephones under field conditions, and the extent of bystander interference under field conditions. A two-channel analog-to-digital converter was used to monitor voltages generated by an acoustic (real-ear) and electromagnetic probe. Digital recordings of interference and speech plus interference were made on a laptop computer. Fifty-three hearing aid wearers listened to interference and speech plus interference through personal communication service 1900 and time division multiple access digital wireless telephones and rated them in terms of annoyance experienced and usability of the wireless telephone. Ratings of annoyance were also done for the bystander condition. Approximately 80 percent of the sample rated the telephones as unusable; on the other hand, 70 to 90 percent experienced no annoying interference from telephones being used by another person seated nearby (bystander condition).

Abbreviations: BTE = behind the ear, CDMA = code division multiple access, EM = electromagnetic, PBX = private branch exchange, PCS = personal communication service, RF = radio frequency, TDMA = time division multiple access
Practical Information for Audiologists on Access to Wireless Telephones
Authors: Harkins Judy
Published: March 2022

Analog cellular telephone service is being phased out in favor of digital wireless services, which are less accessible to people with hearing loss. As a result, audiologists can expect to receive an increasing number of inquiries from clients about using wireless telephones with hearing aids and other assistive technologies. In this article, the underlying transmission technology, telephone handset, roaming, and current solutions to accessibility problems are described. Public policy affecting the accessibility of wireless telephones to people with hearing loss is explained. Alternatives to wireless voice services are explored, and resources for information in a quickly changing industry are provided.

Abbreviations: CDMA = code division multiple access, FCC = Federal Communications Commission, GSM = Global System Mobile Communications, HAC = hearing aid compatible, TDMA = time division multiple access, TTY = text telephone
Hearing Aid and Cellular Telephone Compatibility: Working Toward Solutions
Authors: Berger H. Stephen
Published: March 2022

The ability of hearing aid wearers to use cellular telephones using digital transmission formats has become a prominent issue. This article presents the requirements, technical challenges, and emerging standards for the combined use of hearing aids with cellular telephones.

Abbreviations: ANSI = American National Standards Institute, FCC = Federal Communications Commission, RF = radio frequency
The planning and reflection of police use of force training: a German case study
Authors: Staller Mario S. , Koerner Swen , Heil Valentina , Abraham Andrew , Poolton Jamie
Published: March 2022

The current study aimed to elicit the planning and reflecting processes of police trainers with regards to the delivery of police training. Four police trainers were explicitly asked about their planning for and reflecting on training sessions. In total 34 interviews were conducted (17 pre, 17 post) and analysed. The results indicated that police trainers employ two main strategies to progress their learners towards the aims of the training session. First, they focus on making the learning experience fun and second, they point out the relevance of the to be learnt skills by creating the demand, showcasing mistakes and then subsequently focusing on developing the needed skills in isolated contexts. However, the data indicated that police trainers were generally deficient in their capability to set training session objectives and to align their delivery of training in a coherent and effective way. Furthermore, higher levels of reflection of the delivery of the training session were almost absent. The results identify a need for professional development for police trainers in the areas of planning and reflection.
Quantum friction theory drags experiments toward realization
Authors: Piccone Ashley
Published: March 2022

While quantum friction has yet to be unambiguously detected, changing the geometry and material of the system could increase the force enough for physical measurements.
Adiabatic potential energy surfaces and photodissociation mechanisms for highly excited states of H2O
Authors: An Feng , Han Shanyu , Hu Xixi , Yuan Kaijun , Xie Daiqian
Published: March 2022

Full-dimensional adiabatic potential energy surfaces of the electronic ground state X̃ and nine excited states Ã, Ĩ, B̃, C̃, D̃, D̃′, D̃″, Ẽ′ and F̃ of H2O molecule are developed at the level of internally contracted multireference configuration interaction with the Davidson correction. The potential energy surfaces are fitted by using Gaussian process regression combining permutation invariant polynomials. With a large selected active space and extra diffuse basis set to describe these Rydberg states, the calculated vertical excited energies and equilibrium geometries are in good agreement with the previous theoretical and experimental values. Compared with the well-investigated photodissociation of the first three low-lying states, both theoretical and experimental studies on higher states are still limited. In this work, we focus on all the three channels of the highly excited state, which are directly involved in the vacuum ultraviolet photodissociation of water. In particular, some conical intersections of D̃–Ẽ′, Ẽ′-F̃, Ã–Ĩ and Ĩ–C̃ states are clearly illustrated for the first time based on the newly developed potential energy surfaces (PESs). The nonadiabatic dissociation pathways for these excited states are discussed in detail, which may shed light on the photodissociation mechanisms for these highly excited states.
Effects of intermolecular interactions on luminescence property in organic molecules
Authors: Yang Junfang , Peng Qian
Published: March 2022

The organic solid-state light-emitting materials have attracted more and more attention owing to their promising applications in displays, lasers and optical communications. In contrast to isolated molecule, there are various weak intermolecular interactions in organic solids that sometimes have a large impact on the excited-state properties and energy dissipation pathways, resulting in strong fluorescence/phosphorescence. It is increasingly necessary to reveal the luminescence mechanism of organic solids. Here, we briefly review how intermolecular interactions induce strong normal fluorescence, thermally activate delayed fluorescence and room-temperature phosphorescence in organic solids by examining changes in geometry, electronic structures, electron-vibration coupling and energy dissipation dynamics of the excited states from isolated to aggregated molecules. We hope that the review will contribute to an in-depth understanding of the excited state properties of organic solids and to the design of excellent solid-state light-emitting materials.
Ten-dimensional quantum dynamics study of H+CH3D → H2+CH2D reaction
Authors: Yang Mingjuan , Cheng Tong , Zheng Rui , Song Hongwei , Yang Minghui
Published: March 2022

The mode selectivity of the H+CH3D→H2+CH2D reaction was studied using a recently developed ten-dimensional time-dependent wave packet method. The reaction dynamics are studied for the reactant CH3D initially from the ground state, the CH3 symmetry and asymmetry stretching excitation, the CD stretching excitation and the fundamental and the first overtone of the CH3 bending mode. The calculated reaction probabilities show that exciting either of the CH3 stretching modes enhances the reactivity in the collision energy range below 1.0 eV, while the CD stretching excitation does not obviously prompt the reaction. Fundamental CH3 bending excitation has nearly no effect on promoting reactivity. However, a significant enhancement is observed for the first overtone excitation of the CH3 bending mode, resulting from the Fermi resonance between the fundamental state of the CH3 symmetry stretching mode and the first overtone state of the CH3 bending mode.
Particle-in-cell simulations of THz emission from plasma by oblique collision of two-electron beams
Authors: Kumar Manoj , Kang Teyoun , Song Hyung Seon , Hur Min Sup
Published: March 2022

We studied the THz radiation generated by a beam-plasma system using two-dimensional (2D) particle-in-cell (PIC) simulations. The Langmuir waves excited by two counterpropagating electron beams, via two-stream instability, collide with each other at an oblique angle, which forms a high beam-density modulation near the collision region, where both beam electrons become trapped. As a result, spatially localized Langmuir wave packets with large longitudinal-electric field amplitudes are formed, which give rise to bursts of electromagnetic radiation. Our 2D PIC simulations of the two thin, low-density, asymmetric, electron beams colliding obliquely show that a strong THz emission is obtained at the second harmonic of the plasma frequency (f = 1.0 THz), with a narrow spectral width (∼0.80%) in vacuum and significantly higher efficiency than the head-on-collision case. The efficiency of power conversion from electron beams to THz radiation measured in vacuum reaches around ∼0.0289, for a continuous injection of beams into the plasma, making it suitable for applications requiring high-power narrow-band THz radiation sources.
Epilepsy detection with artificial neural network based on as-fabricated neuromorphic chip platform
Authors: Liu Y. H. , Chen L. , Li X. W. , Wu Y. C. , Liu S. , Wang J. J. , Hu S. G. , Yu Q. , Chen T. P. , Liu Y.
Published: March 2022

Epilepsy is a serious neurological condition caused by a sudden abnormality of brain neurons. An accurate epilepsy detection based on electroencephalogram (EEG) signals can provide vital information for diagnosis and treatment. In this study, we propose a lightweight automatic epilepsy detection system with artificial neural network based on our as-fabricated neuromorphic chip. The proposed system utilizes a neural network model to achieve high-accuracy detection without the need for epilepsy-related prior knowledge. The model uses a filter module and a convolutional neural network to preprocess the raw EEG signal and uses a long short-term memory recurrent neural network and a fully connected network as the classifier. In the examination, the classification accuracy of the normal cases and seizures approaches 99.10%, and the accuracy of the normal cases, and interictal and seizure cases can reach 94.46%. This design provides possible epilepsy detection in wearable or portable devices.
Edge plasma relaxations due to diamagnetic stabilization
Authors: Cianfrani Francesco , Fuhr Guillaume , Beyer Peter
Published: March 2022

A new mechanism for pressure profile relaxations in an edge tokamak plasma is derived from simulations within the two-fluid three-dimensional turbulence code EMEDGE3D. The relaxation is due to diamagnetic coupling in the resistive ballooning/drift wave dynamics: Unstable modes experience explosive growth at high pressure gradients after a phase in which they are stabilized by the diamagnetic coupling leading to the onset of a transport barrier. The sheared E × B flow does not play any significant role. After relaxation, the transport barrier forms again and it sets the conditions for a new relaxation event, resulting in an oscillatory behavior. We find that energy flux into the scrape-off layer decreases with the increasing oscillation frequency and that the oscillations are tamed by increasing plasma temperature. This behavior is reminiscent of the so-called type-III edge localized modes. A one-dimensional model reproducing the relaxations is also derived.
Asymmetric Holmboe instabilities in arrested salt-wedge flows
Authors: Yang Adam J. K. , Tedford E. W. , Olsthoorn J. , Lawrence G. A.
Published: March 2022

The asymmetric Holmboe instabilities that form on an arrested salt wedge are investigated in the laboratory. The flow is characterized by three regions. Near the tip of the salt wedge, there is little wave activity; immediately downstream, mostly positive waves form; further downstream, both positive and negative waves are present. The appearance of these regions is determined by the spatial variation in the thickness of the saline layer, the shear layer thickness, and the offset between the density interface and velocity interface. We predict the growth of the instabilities by applying linear stability theory to the mean flow field. The predicted initial growth rate is consistent with the laboratory measurements until the Holmboe wave reaches a steepness ratio of 5–7 %. Then, the growth of the Holmboe wave is nonlinear. We found that the Holmboe wavelength increases downstream along the salt wedge. This wave stretching is related to the increase in the shear layer thickness and is supported by the gradual acceleration of the upper layer fluid. Eventually, the growth of the wave amplitude and the wave stretching balance a maximum wave steepness ratio of 10%. Although the wave is nonlinear, the predicted wave speed and wavelength are consistent with the laboratory measurements.
Habitat-specific performance of high-frequency acoustic telemetry tags in a tropical marine environment
Authors: Matley J. K. , Vargas-Araya L. , Fisk A. T. , Espinoza M.
Published: March 2022

High-frequency (>175 kHz) acoustic telemetry transmitters are increasingly being used to track the movements of small fishes and other aquatic organisms. These transmitters, which are often smaller than conventional types, have primarily been used in freshwater, yet limited information is available on their efficacy in estuarine or marine environments. This study quantified detection ranges (DR) of 180-kHz tags and potential environmental factors influencing detection probability in three different habitats within a large embayment in Costa Rica. Mangrove (DR at 50% detection efficiency; DR50 = 121.0 m ± 8.1 s.e.) and transitional estuarine (DR50 = 145.6 m ± 12.2) habitats had relatively high detection ranges, albeit smaller than similar studies in freshwater, highlighting the effectiveness of using this frequency in tropical marine environments. By contrast, performance within rocky reef habitat was poor (DR50 consistently <0 m), which may have been caused by the heterogeneous bottom structure or close proximity detection interference (CPDI) due to ambient noise. This study provides novel information on the performance of high-frequency acoustic tags in a tropical marine environment serving as an important case study as investigations of the spatial ecology of small fishes in both marine and freshwater become more common.
Adaptive Monte Carlo augmented with normalizing flows
Authors: Gabrié Marylou , Rotskoff Grant M. , Vanden-Eijnden Eric
Published: March 2022

Significance

Monte Carlo methods, tools for sampling data from probability distributions, are widely used in the physical sciences, applied mathematics, and Bayesian statistics. Nevertheless, there are many situations in which it is computationally prohibitive to use Monte Carlo due to slow “mixing” between modes of a distribution unless hand-tuned algorithms are used to accelerate the scheme. Machine learning techniques based on generative models offer a compelling alternative to the challenge of designing efficient schemes for a specific system. Here, we formalize Monte Carlo augmented with normalizing flows and show that, with limited prior data and a physically inspired algorithm, we can substantially accelerate sampling with generative models.
Assessing the roles of nitrogen, biomass, and niche dimensionality as drivers of species loss in grassland communities
Authors: Band Nir , Kadmon Ronen , Mandel Micha , DeMalach Niv
Published: March 2022

Significance

Nutrient enrichment of natural ecosystems is a primary characteristic of the Anthropocene and a known cause of biodiversity loss, particularly in grasslands. In a global meta-analysis of 630 resource addition experiments, we conduct a simultaneous test of the three most prominent explanations of this phenomenon. Our results conclusively indicate that nitrogen is the leading cause of species loss. This result is important because of the increase in nitrogen deposition and the frequent use of nitrogen-based fertilizers worldwide. Our findings provide global-scale, experimental evidence that minimizing nitrogen inputs to ecological systems may help to conserve the diversity of grassland ecosystems.
Discovering disease-causing pathogens in resource-scarce Southeast Asia using a global metagenomic pathogen monitoring system
Authors: Bohl Jennifer A. , Lay Sreyngim , Chea Sophana , Ahyong Vida , Parker Daniel M. , Gallagher Shannon , Fintzi Jonathan , Man Somnang , Ponce Aiyana , Sreng Sokunthea , Kong Dara , Oliveira Fabiano , Kalantar Katrina , Tan Michelle , Fahsbender Liz , Sheu Jonathan , Neff Norma , Detweiler Angela M. , Yek Christina , Ly Sokna , Sath Rathanak , Huch Chea , Kry Hok , Leang Rithea , Huy Rekol , Lon Chanthap , Tato Cristina M. , DeRisi Joseph L. , Manning Jessica E.
Published: March 2022

Significance

Metagenomic pathogen sequencing offers an unbiased approach to characterizing febrile illness. In resource-scarce settings with high biodiversity, it is critical to identify disease-causing pathogens in order to understand burden and to prioritize efforts for control. Here, metagenomic next-generation sequencing (mNGS) characterization of the pathogen landscape in Cambodia revealed diverse vector-borne and zoonotic pathogens irrespective of age and gender as risk factors. Identification of key pathogens led to changes in national program surveillance. This study is a “real world” example of the use of mNGS surveillance of febrile individuals, executed in-country, to identify outbreaks of vector-borne, zoonotic, and other emerging pathogens in a resource-scarce setting.
Strain and rupture of HIV-1 capsids during uncoating
Authors: Yu Alvin , Lee Elizabeth M. Y. , Briggs John A. G. , Ganser-Pornillos Barbie K. , Pornillos Owen , Voth Gregory A.
Published: March 2022

Significance

The mature capsids of HIV-1 are transiently stable complexes that self-assemble around the viral genome during maturation, and uncoat to release preintegration complexes that archive a double-stranded DNA copy of the virus in the host cell genome. However, a detailed view of how HIV cores rupture remains lacking. Here, we elucidate the physical properties involved in capsid rupture using a combination of large-scale all-atom molecular dynamics simulations and cryo-electron tomography. We find that intrinsic strain on the capsid forms highly correlated patterns along the capsid surface, along which cracks propagate. Capsid rigidity also increases with high strain. Our findings provide fundamental insight into viral capsid uncoating.
North and South: Naming practices and the hidden dimension of global disparities in knowledge production
Authors: Castro Torres Andrés F. , Alburez-Gutierrez Diego
Published: March 2022

Significance

Contemporary social sciences aim to be diverse and inclusive, but traces of the historical dominance of Western European and North American academic institutions persist in scientific practices. One such practice is the phrasing of article titles. Our analysis shows that articles studying the global North are systematically less likely to mention the name of the country they study in their title compared to articles on the global South. This constitutes, potentially, an unwarranted claim on universality and may lead to lesser recognition of global South studies. Social and behavioral scientists must reflect on the phrasing of their article titles to avoid reproducing harmful relations of intellectual domination which limit inclusivity and constitute a barrier to the generalizability of scientific knowledge.
Structural basis for impaired 5′ processing of a mutant tRNA associated with defects in neuronal homeostasis
Authors: Lai Lien B. , Lai Stella M. , Szymanski Eric S. , Kapur Mridu , Choi Edric K. , Al-Hashimi Hashim M. , Ackerman Susan L. , Gopalan Venkat
Published: March 2022

Significance

Understanding and treating neurological disorders are global priorities. Some of these diseases are engendered by mutations that cause defects in the cellular synthesis of transfer RNAs (tRNAs), which function as adapter molecules that translate messenger RNAs into proteins. During tRNA biogenesis, ribonuclease P catalyzes removal of the transcribed sequence upstream of the mature tRNA. Here, we focus on a cytoplasmic tRNA
Arg
UCU
that is expressed specifically in neurons and, when harboring a particular point mutation, contributes to neurodegeneration in mice. Our results suggest that this mutation favors stable alternative structures that are not cleaved by mouse ribonuclease P and motivate a paradigm that may help to understand the molecular basis for disease-associated mutations in other tRNAs.
Epigenetic MRI: Noninvasive imaging of DNA methylation in the brain
Authors: Lam Fan , Chu James , Choi Ji Sun , Cao Chang , Hitchens T. Kevin , Silverman Scott K. , Liang Zhi-Pei , Dilger Ryan N. , Robinson Gene E. , Li King C.
Published: March 2022

Significance

Dynamic epigenetic activity is a fundamental mechanism underpinning how the brain changes its function during development and aging and in response to environmental and disease stimuli. We developed a technology called epigenetic MRI (eMRI) that enables noninvasive imaging of DNA methylation in the brain, a major epigenetic mechanism. eMRI reveals strong regional differences in global DNA methylation in pig brains, a model with stronger resemblance to human brains than are rodents. Given the noninvasive nature of eMRI, our results pave the way for a DNA-methylation imaging paradigm for living human brains. We expect eMRI to enable many studies to unravel the molecular control of brain function and disease.
An Fgf–Shh positive feedback loop drives growth in developing unpaired fins
Authors: Hawkins M. Brent , Jandzik David , Tulenko Frank J. , Cass Amanda N. , Nakamura Tetsuya , Shubin Neil H. , Davis Marcus C. , Stock David W.
Published: March 2022

The origin and diversification of appendage types is a central question in vertebrate evolution. Understanding the genetic mechanisms that underlie fin and limb development can reveal relationships between different appendages. Here we demonstrate, using chemical genetics, a mutually agonistic interaction between Fgf and Shh genes in the developing dorsal fin of the channel catfish,Ictalurus punctatus. We also find that Fgf8 and Shh orthologs are expressed in the apical ectodermal ridge and zone of polarizing activity, respectively, in the median fins of representatives from other major vertebrate lineages. These findings demonstrate the importance of this feedback loop in median fins and offer developmental evidence for a median fin-first scenario for vertebrate paired appendage origins.
EMI as discursive positioning
Authors: Trent John
Published: March 2022

Set against a background of societal pressure and preference for English language education in Hong Kong, this paper explores the policy and practice of English medium instruction (EMI) from the perspective of one group of content subject teachers. Grounded in Bakhtin’s dialogism, the paper reports the results of a qualitative study that used in-depth interviews to explore the perspectives and experiences of these teachers as they implement EMI policy in Hong Kong schools. The results reveal the existence of several discourses of EMI in Hong Kong that position the teachers at community, institutional, and professional levels. The results also suggest that the interplay of EMI discourses can offer content subject teachers positions which they regard as undesirable. Suggestions for ensuring that the voices of these teachers are heard within the context of teacher professional development opportunities in EMI settings are considered and implications for future research are discussed.
L2 processing of filled gaps
Authors: Dong Zhiyin Renee , Han Chao , Hestvik Arild , Hermon Gabriella
Published: March 2022

This paper investigates how late L2 learners resolve filler-gap dependencies (FGD) in real-time and how proficiency and working memory (WM) modulate their brain responses in an event-related potential (ERP) experiment. A group of intermediate to highly proficient Mandarin Chinese learners of English listened to sentences such as “The zebra that the hippo kissed *the camel on the nose ran far away,” in which the extra noun phrase “the camel” created a ‘filled-gap’ effect. The results show that although L2 behavioral responses are comparable to native speakers and are positively correlated with proficiency and WM span, the brain responses to the filled gap are qualitatively different. Importantly, L2 processing patterns did not become more nativelike with higher proficiency levels or greater WM capacity. Specifically, while the native speakers exhibited a P600 typically observed for syntactic violations and repair, the L2 group produced a prefrontal-central positivity. Similar ERPs have previously been reported to reflect domain-general attentional and non-structural-based processes, suggesting that the L2 group has a reduced sensitivity to structural requirements for gap positing in the online resolution of FGDs. Our findings are discussed in light of various proposals accounting for L1-L2 processing differences, including the Shallow Structure Hypothesis.
Openness to experience, absorption-like states, and the aesthetic, explanatory, and pragmatic effects of literary reading
Authors: Kuiken Don , Douglas Shawn , Kuijpers Moniek
Published: March 2022

Although several measures of reading engagement (e.g., absorption, immersion) have been developed in recent years, the possibility that they reflect different constructs has not been systematically examined. The present study investigated two factorially independent forms of reading engagement measured by the Absorption-Like States Questionnaire (ASQ;Kuiken & Douglas, 2017,2018). We examined whether (a) expressive enactment (ASQ-EE) and integrative comprehension (ASQ-IC) differentially predict aesthetic, explanatory, and pragmatic reading outcomes; (b) whether the components and outcomes of ASQ-EE and ASQ-IC differ from those of another measure of reading engagement (the Story World Absorption Scale, SWAS;Kuijpers et al., 2014), and (c) whether ASQ-EE and ASQ-IC are differentially related to two measures of trait openness to experience: the Tellegen Absorption Scale (Tellegen & Atkinson, 1974) and the Big Five Aspects Scale for Openness/Intellect;DeYoung et al., 2007).
High-power wire arc additive manufacturing of stainless steel with active heat management
Authors: Long Jinwei , Wang Meng , Zhao Wenyong , Zhang Xujing , Wei Yanhong , Ou Wenmin
Published: March 2022

Wire arc additive manufacturing (WAAM) process is widely used in large steel components. However, WAAM severe heat accumulation reduced the accuracy of the products, its microstructure and mechanical properties also deteriorate. Compared with common steel, it is more difficult to get complicated stainless steel components with WAAM due to its weak heat dispersion. To efficiently mitigate the heat accumulation, this paper presented a water-medium active cooling additive manufacturing system to complete a 304 stainless steel thin-walled structure. As a result, taller and narrower thin-walled parts could be gotten with 7% increase in average height and 13% decrease in average width. Simultaneously, the surface waviness is reduced, grains are refined and fracture properties of thin-walled parts are improved.
Infinite-derivative linearized gravity in convolutional form
Authors: Heredia Carlos , Kolář Ivan , Llosa Josep , Maldonado Torralba Francisco José , Mazumdar Anupam
Published: March 2022

This article aims to transform the infinite-order Lagrangian density for ghost-free infinite-derivative linearized gravity into non-local form. To achieve it, we use the theory of generalized functions and the Fourier transform in the space of tempered distributions

S

′

. We show that the non-local operator domain is not defined on the whole functional space but on a subset of it. Moreover, we prove that these functions and their derivatives are bounded in all

R

3

and, consequently, the Riemann tensor is regular and the scalar curvature invariants do not present any spacetime singularity. Finally, we explore what conditions we need to satisfy so that the solutions of the linearized equations of motion exist in

S

′

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

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

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

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

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

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

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

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

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

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

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.
An apodized cubic phase mask used in a wavefront coding system to extend the depth of field
Authors: Zhu Lina , Li Fei , Huang Zeyu , Zhao Tingyu
Published: March 2022

The point spread function (PSF) caused by a wavefront coding system with a cubic phase mask has big side-lobes which leads to bad image restoration. This paper proposes a novel apodized cubic phase mask to suppress the side-lobes of the PSF. Simulated annealing algorithm is used to optimize the cubic and the truncation parameter of the phase mask. The system with the novel phase mask has better performance in the modulation transfer function (MTF) especially in low-and-medium spatial frequency region. The simulation results show that the restored images with the novel phase mask are superior to the one with the classic cubic phase mask in contrast and ringing effect. The experimental results show that the side-lobes of the PSF are suppressed by using the apodized cubic phase mask.
Enhancing performance of GaN-based LDs by using GaN/InGaN asymmetric lower waveguide layers
Authors: Wang Wen-Jie , Liao Ming-Le , Yuan Jun , Luo Si-Yuan , Huang Feng
Published: March 2022

The effects of GaN/InGaN asymmetric lower waveguide (LWG) layers on photoelectrical properties of InGaN multiple quantum well laser diodes (LDs) with an emission wavelength of around 416 nm are theoretically investigated by tuning the thickness and the indium content of InGaN insertion layer (InGaN-IL) between the GaN lower waveguide layer and the quantum wells, which is achieved with the Crosslight Device Simulation Software (PIC3D, Crosslight Software Inc.). The optimal thickness and the indium content of the InGaN-IL in lower waveguide layers are found to be 300 nm and 4%, respectively. The thickness of InGaN-IL predominantly affects the output power and the optical field distribution in comparison with the indium content, and the highest output power is achieved to be 1.25 times that of the reference structure (symmetric GaN waveguide), which is attributed to the reduced optical absorption loss as well as the concentrated optical field nearby quantum wells. Furthermore, when the thickness and indium content of InGaN-IL both reach a higher level, the performance of asymmetric quantum wells LDs will be weakened rapidly due to the obvious decrease of optical confinement factor (OCF) related to the concentrated optical field in the lower waveguide.
A 4×4 metal-semiconductor-metal rectangular deep-ultraviolet detector array of Ga2O3 photoconductor with high photo response
Authors: Liu Zeng , Zhi Yu-Song , Zhang Mao-Lin , Yang Li-Li , Li Shan , Yan Zu-Yong , Zhang Shao-Hui , Guo Dao-You , Li Pei-Gang , Guo Yu-Feng , Tang Wei-Hua
Published: March 2022

A 4×4 beta-phase gallium oxide (β-Ga2O3) deep-ultraviolet (DUV) rectangular 10-fingers interdigital metal-semiconductor-metal (MSM) photodetector array of high photo responsivity is introduced. The Ga2O3 thin film is prepared through the metalorganic chemical vapor deposition technique, then used to construct the photodetector array via photolithography, lift-off, and ion beam sputtering methods. The one photodetector cell shows dark current of 1.94 pA, photo-to-dark current ratio of 6×107, photo responsivity of 634.15 A⋅W−1, specific detectivity of 5.93×1011 cm⋅Hz1/2⋅W−1 (Jones), external quantum efficiency of 310000%, and linear dynamic region of 108.94 dB, indicating high performances for DUV photo detection. Furthermore, the 16-cell photodetector array displays uniform performances with decent deviation of 19.6% for photo responsivity.