bluuebunny/crossref_metadata_2025 huggingface dataset:
A novel fluorescent probe with a pyrazolo[4,3-c]quinoline core selectively recognizes c-MYC promoter G-quadruplexes
Authors: Mohamed Hany I. , Gao Chao , Gui Zhikun , Song Zibing , Wei Dengguo
Published: April 2022

An aptamer combined with a c-MYC-selective fluorophore could work as the fluorescent core of nucleic acid mimics of fluorescent proteins to locate and image functional biomolecules in cells.
Ir-Catalyzed cyclization of α,ω-dienes with an N-methyl group via two C–H activation steps
Authors: Tanaka Katsumasa , Hattori Hiroshi , Yabe Ryota , Nishimura Takahiro
Published: April 2022

Ir-Catalyzed cyclization of 1,5- and 1,6-dienes via C–H alkylation of an N-methyl group proceeded to give five- and six-membered carbocyclic compounds, respectively. The reaction using a chiral diphosphine ligand enabled the asymmetric cyclization.
Bandgaps of atomically precise graphene nanoribbons and Occam's razor
Authors: Zdetsis Aristides D.
Published: April 2022

Simple DFT calculations and general symmetry arguments can resolve open questions (?) and conflicting results obtained by complex high-level methods on various AGNR-bandgaps (ΔEac, ΔEzz, Δεζζ with very high accuracy (!) in accord with Occam’s razor.
Modeling the heating and cooling of a chromophore after photoexcitation
Authors: Ventura Elizete , Andrade do Monte Silmar , T. do Casal Mariana , Pinheiro Max , Toldo Josene Maria , Barbatti Mario
Published: April 2022

An analytical energy-transfer model is implemented to obtain a chromophore's heating and cooling times in a given solvent by using quantities available in nonadiabatic dynamics simulations.
Recent advances in hydrothermal synthesis of facet-controlled CeO2-based nanomaterials
Authors: Zhu Yuanzheng , Chen Chunguang , Cheng Ping , Ma Jie , Yang Weibang , Yang Weixin , Peng Yaru , Huang Yiguo , Zhang Shuping , Seong Gimyeong
Published: April 2022

A comprehensive understanding of the hydrothermal synthesis of facet-controlled CeO2-based nanomaterials and their facet-dependent performance in catalytic applications.
Shape-controlled Mn–Fe PBA derived micromotors for organic pollutant removal
Authors: Huang Jing , Shan Qi , Fang Yanan , Zhao Ning , Feng Xiaomiao
Published: April 2022

A new strategy is employed to prepare Mn–Fe PBA derived oxide micromotors with excellent motion performances through co-precipitation and heat treatment, which can be used for organic pollutant degradation with recycling and reusing advantages.
Intelligent control of nanoparticle synthesis through machine learning
Authors: Lv Honglin , Chen Xueye
Published: April 2022

Machine learning-assisted synthesis of nanoparticles.
Engineering novel surface electronic states via complex supramolecular tessellations
Authors: Hu Wenqi , Kher-Elden Mohammad A. , Zhang Hexu , Cheng Peng , Chen Lan , Piquero-Zulaica Ignacio , Abd El-Fattah Zakaria M. , Barth Johannes V. , Wu Kehui , Zhang Yi-Qi
Published: April 2022

Interfacial complex supramolecular tessellations were employed to derive novel two-dimensional electronic structures from Shockley surface-state, giving rise to Kagome or Dirac bands as well as hybrid band structures through quantum dots coupling.
In situ fluorescence yield soft X-ray absorption spectroscopy of electrochemical nickel deposition processes with and without ethylene glycol
Authors: Yamaguchi Akinobu , Akamatsu Naoya , Saegusa Shunya , Nakamura Ryo , Utsumi Yuichi , Kato Masaru , Yagi Ichizo , Ishihara Tomoko , Oura Masaki
Published: April 2022

Schematic drawing of electrochemical reactions of the Pt-coated SiC electrode, which separates the vacuum and the solution containing Ni2+ and ethylene glycol, in our spectro-electrochemical setup for the FY-XAS.
Insights into coloration enhancement of mercerized cotton fabric on reactive dye digital inkjet printing
Authors: Zhao Hongzhi , Zhang Kun , Fang Kuanjun , Shi Furui , Pan Ying , Sun Fuyun , Wang Dezhen , Xie Ruyi , Chen Weichao
Published: April 2022

Mercerization can control the crystallinity of cotton fiber, promote the absorption of ink droplets' wick into the fiber and inhibit ink droplets from penetrating the back of fabric. Therefore, the printing quality was extremely enhanced.
Are PARPs promiscuous?
Authors: Feijs Karla L.H. , Žaja Roko
Published: April 2022

Post-translational modifications exist in different varieties to regulate diverse characteristics of their substrates, ultimately leading to maintenance of cell health. The enzymes of the intracellular poly(ADP-ribose) polymerase (PARP) family can transfer either a single ADP-ribose to targets, in a reaction called mono(ADP-ribosyl)ation or MARylation, or multiple to form chains of poly(ADP-ribose) or PAR. Traditionally thought to be attached to arginine or glutamate, recent data have added serine, tyrosine, histidine and others to the list of potential ADP-ribose acceptor amino acids. PARylation by PARP1 has been relatively well studied, whereas less is known about the other family members such as PARP7 and PARP10. ADP-ribosylation on arginine and serine is reversed by ARH1 and ARH3 respectively, whereas macrodomain-containing MACROD1, MACROD2 and TARG1 reverse modification of acidic residues. For the other amino acids, no hydrolases have been identified to date. For many PARPs, it is not clear yet what their endogenous targets are. Better understanding of their biochemical reactions is required to be able to determine their biological functions in future studies. In this review, we discuss the current knowledge of PARP specificity in vitro and in cells, as well as provide an outlook for future research.
SpikeGoogle: Spiking Neural Networks with GoogLeNet‐like inception module
Authors: Wang Xuan , Zhong Minghong , Cheng Hoiyuen , Xie Junjie , Zhou Yingchu , Ren Jun , Liu Mengyuan
Published: April 2022

Spiking Neural Network is known as the third‐generation artificial neural network whose development has great potential. With the help of Spike Layer Error Reassignment in Time for error back‐propagation, this work presents a new network called SpikeGoogle, which is implemented with GoogLeNet‐like inception module. In this inception module, different convolution kernels and max‐pooling layer are included to capture deep features across diverse scales. Experiment results on small NMNIST dataset verify the results of the authors’ proposed SpikeGoogle, which outperforms the previous Spiking Convolutional Neural Network method by a large margin.
Transient electric field of the combined insulation structure under positive periodic square waveform voltage: Analytical analysis and application
Authors: Wen Teng , Cui Xiang , Li Xuebao , Liu Sijia , Zhao Zhibin
Published: April 2022

The working voltage of the high‐voltage high‐power electronic devices is the positive periodic square waveform (PPSW) voltage, which is much different from the conventional AC or DC voltage. For the composite insulation structure of devices, it is important to analyse the transient electric field under the PPSW voltage. However, the existing investigations are often conducted under the electrostatic field due to the high frequency of the PPSW voltage. Thus, the transient characteristics of the electric field are missed. To obtain some qualitative conclusions, this paper focusses on the theoretical analysis of the transient characteristics of electric field for the composite insulation structure under the PPSW voltage. First, the formula of the electric field intensity and the interfacial charge density are derived analytically. Second, the influence of the cycle and the duty cycle on the transient characteristics are investigated. Third, the maximum of the electric field intensity and the interfacial charge density in the positive square waveform steady‐state are discussed in detail. Besides, the engineering calculation methods for obtaining these maximum values are also suggested. Lastly, an actual model is employed to testify the validity of the analytical analysis. This work is significant for the numerical calculation of the transient electric field of composite insulation structure under the PPSW voltage in engineering.
Smile face array: Generating oblique incident and front output vortex beam for both TE and TM waves
Authors: Zhu Chenghui , Liu Xiaoming , Wang Chen , Yang Xiaofan , Gan Lu , Sun Lijun
Published: April 2022

A single layer reflective array is designed to generate orbital angular momentum (OAM) beam at microwave frequency. The unit cell of this design is smile face shape distributed over a planar surface. Phase modulation can be realised by changing the size of each unit cell, with very low variation in reflection amplitude. By careful design, oblique incident can be obtained, reducing feed blockage to the output beam. The direction of the output beam can also be intendedly designed. In this work, the front output is chosen as a demonstrative example. In addition, the input beam can be either TE or TM wave, enable dual‐mode operation. Furthermore, it is flexible to design the topological mode of the output OAM. The smile array is developed by cutting slots on circular patch array to produce perturbation on TE and TM waves, so that the difference in TE and TM incidence is reduced. As an instance, the topological modes of l = (−2, −1, 1, 2) are simulated, and the mode l = 1 is fabricated and measured. Measurements are conducted for both near field and far field. The measured results show good agreement with the simulated ones, indicating that this dual mode design works satisfactorily when oblique feed is used.
The VVV survey: Long-period variable stars
Authors: Nikzat F. , Ferreira Lopes C. E. , Catelan M. , Contreras Ramos R. , Zoccali M. , Rojas-Arriagada A. , Braga V. F. , Minniti D. , Borissova J. , Becker I.
Published: April 2022

Context. Long-period variable stars (LPVs) are pulsating red giants, primarily in the asymptotic giant branch phase, and they include both Miras and semi-regular variables (SRVs). Their period-age and period-luminosity relations enable us to trace different stellar populations, as they are intrinsically very bright and cover a wide range in distances and ages.

Aims. The purpose of this study is to establish a census of LPV stars in a region close to the Galactic center, using the six-year database of the Vista Variables in the Vía Láctea (VVV) ESO Public Survey, as well as to describe the methodology that was employed to search for and characterize LPVs using VVV data. Near-IR surveys such as VVV provide a unique opportunity to probe the high-extinction innermost regions of the Milky Way. The detection and analysis of the intrinsically bright Miras in this region could provide us with an excellent probe of the properties of the Milky Way far behind its bulge.

Methods. We used point-spread function photometry for all available Ks-band images in ten VVV tiles, covering 16.4 deg2 in total, overlapping fields observed in the course of the Optical Gravitational Lensing Experiment (OGLE)-III survey. We designed a method to select LPV candidates, and we used the known variables from OGLE-III and other known variables from the literature to test our approach. The reduced χ2 statistic, along with the flux-independent index K(fi), were used in our analysis. The Lomb-Scargle period search method, Fourier analysis, template fitting, and visual inspection were then performed to refine our sample and characterize the properties of the stars included in our catalog.

Results. A final sample of 130 Mira candidates, of which 129 are new discoveries, was thus obtained, with periods in the range between about 80 and 1400 days. Moreover, a sample of 1013 LPV candidates is also presented, whose periods are however not sufficiently constrained by the available data. A fraction of the latter may eventually turn out to be SRVs. Ages are measured for these stars based on a reassessment of the period-age relations available in the literature. The Miras in our catalog include 18 stars satisfying the requirements to serve as reliable distance indicators and which are not saturated in the VVV Ks-band images. Their distances are accordingly derived and discussed. A number of objects that are seemingly placed far behind the Milky Way’s bulge was detected.
The origin of early-type runaway stars from open clusters
Authors: Bhat A. , Irrgang A. , Heber U.
Published: April 2022

Runaway stars are ejected from their place of birth in the Galactic disk, with some young B-type runaways found several tens of kiloparsecs from the plane traveling at speeds beyond the escape velocity, which calls for violent ejection processes. Young open clusters are a likely place of origin, and ejection may be either through N-body interactions or in binary supernova explosions. The most energetic events may require dynamical interaction with massive black holes. The excellent quality of Gaia astrometry opens up the path to study the kinematics of young runaway stars to such a high precision that the place of origin in open stellar clusters can be identified uniquely even when the star is a few kiloparsecs away. We developed an efficient minimization method to calculate whether two or more objects may come from the same place, which we tested against samples of Orion runaways. Our fitting procedure was then used to calculate trajectories for known runaway stars, which have previously been studied from HIPPARCOS astrometry as well as known open clusters. For runaways in our sample we used Gaia data and updated radial velocities, and found that only half of the sample could be classified as runaways. The other half of the sample moves so slowly (< 30 km s−1) that they have to be considered as walkaway stars. Most of the latter stars turned out to be binaries. We identified parent clusters for runaways based on their trajectories. We then used cluster age and flight time of the stars to investigate whether the ejection was likely due to a binary supernova or due to a dynamical ejection. In particular we show that the classical runaways AE Aurigae and μ Columbae might not have originated together, with μ Columbae having an earlier ejection from Collinder 69, a cluster near the ONC. The second sample investigated comprises a set of distant runaway B stars in the halo which have been studied carefully by quantitative spectral analyses. We are able to identify candidate parent clusters for at least four stars including the hyper-runaway candidate HIP 60350. The ejection events had to be very violent, ejecting stars at velocities as large as 150–400 km s−1.
BEYONDPLANCK
Authors: Herman D. , Hensley B. , Andersen K. J. , Aurlien R. , Banerji R. , Bersanelli M. , Bertocco S. , Brilenkov M. , Carbone M. , Colombo L. P. L. , Eriksen H. K. , Foss M. K. , Fuskeland U. , Galeotta S. , Galloway M. , Gerakakis S. , Gjerløw E. , Iacobellis M. , Ieronymaki M. , Ihle H. T. , Jewell J. B. , Karakci A. , Keihänen E. , Keskitalo R. , Maggio G. , Maino D. , Maris M. , Paradiso S. , Partridge B. , Reinecke M. , Suur-Uski A.-S. , Svalheim T. L. , Tavagnacco D. , Thommesen H. , Wehus I. K. , Zacchei A.
Published: April 2022

We constrained the level of polarized anomalous microwave emission (AME) on large angular scales usingPlanckLow-Frequency Instrument (LFI) and WMAP polarization data within a Bayesian cosmic microwave background (CMB) analysis framework. We modeled synchrotron emission with a power-law spectral energy distribution, as well as the sum of AME and thermal dust emission through linear regression with thePlanckHigh-Frequency Instrument (HFI) 353 GHz data. This template-based dust emission model allowed us to constrain the level of polarized AME while making minimal assumptions on its frequency dependence. We neglected CMB fluctuations, but show through simulations that these fluctuations have a minor impact on the results. We find that the resulting AME polarization fraction confidence limit is sensitive to the polarized synchrotron spectral index prior. In addition, for prior meansβs < −3.1 we find an upper limit ofpAMEmax ≲ 0.6% (95% confidence). In contrast, for meansβs = −3.0, we find a nominal detection ofpAME = 2.5 ± 1.0% (95% confidence). These data are thus not strong enough to simultaneously and robustly constrain both polarized synchrotron emission and AME, and our main result is therefore a constraint on the AME polarization fraction explicitly as a function ofβs. Combining the currentPlanckand WMAP observations with measurements from high-sensitivity low-frequency experiments such as C-BASS and QUIJOTE will be critical to improve these limits further.
Comparing Intraspecific Aggressiveness in Phytophthora cinnamomi Isolates
Authors: Bairrão Margarida , Trindade Manuel , Valdiviesso Teresa , Silva Márcia , Trindade Cândida Sofia , Ferreira Ricardo Boavida , Cordovil Cláudia , Machado Helena
Published: April 2022

Phytophthora cinnamomi is a major plant destructive pathogen with a wide range of hosts and is considered one of the main causes of Quercus spp. decline in the Southwest of the Iberian Peninsula. This study compares two inoculation tests, using simple and fast methodologies, in order to select the most aggressive isolate to use in future Quercus suber inoculation experiments. To evaluate P. cinnamomi intraspecific variability, cork oak excised shoots were inoculated with five isolates, obtained from Q. suber, Quercus rotundifolia and Castanea sativa stands. These isolates were used for in vitro inoculation of a Trifolium subterraneum cultivar available in Portugal in order to assess its usefulness as a "model plant" in rapid screening tests. This study revealed intraspecific variability of P. cinnamomi isolates to cause lesions in Q. suber excised shoots and in the number of T. subterraneum developing lesions on stem and leaves. However, there was no correspondence between the aggressiveness of the isolates in subterranean clover and in the cork oak. Only one isolate showed consistency in aggressiveness regardless of the host species. In conclusion, T. subterraneum is not a good "model plant" for the evaluation of P. cinnamomi isolates aggressiveness.
Impact of the COVID-19 Pandemic on Delivery of Gynecology and Obstetrics Services at a Maximum Care University Hospital in Germany
Authors: Griewing Sebastian , Wagner Uwe , Lingenfelder Michael , Heinis Sylvia , Schieffer Bernhard , Markus Birgit
Published: April 2022

Einleitung Die COVID-19-Pandemie bedeutet einschneidende Maßnahmen für das nationale Gesundheitssystem. Dies bot den Anlass, die klinischen und ökonomischen Leistungsindikatoren der
gynäkologischen und geburtshilflichen Versorgung des Universitätsklinikums Marburg als regionaler universitärer Maximalversorger zu analysieren. Hierzu wurden die Auswirkungen auf die
monatlichen stationären und ambulanten Fallzahlvolumina sowie die entsprechenden ICD- und DRG-Kodierungen ausgewertet, um etwaige Versorgungsdefizite aufzudecken.

Material und Methoden Die Studie basiert auf einer retrospektiven Datenanalyse therapierter stationären und ambulanten Fälle der Jahre 2016 bis 2020. Hierzu wurden über das
klinikinterne Leistungscontrolling-Programm QlikView die Daten von 9487 Fällen der Klinik für Gynäkologie und 19597 Fällen der Klinik für Geburtshilfe ausgewertet.

Ergebnisse Es bildet sich eine der nationalen Pandemiedynamik folgende Abnahme der gynäkologischen stationären Fallzahlen um –6% ab, während das geburtshilfliche Fallzahlvolumen um
+11% im Jahr 2020 steigt. Insgesamt fallen die Effekte für die ambulante Versorgung geringer aus. Zudem lässt sich eine standortbezogene Abnahme der C50 „Bösartige Neubildungen der
Brustdrüse“ und C56 „Bösartige Ovarialtumoren“ Diagnosen um –7,4% bzw. –14% feststellen. Eine Rückkehr zu dem Leistungsniveau des Vorjahres konnte im ambulanten in 3 und im stationären
Sektor in 5 Monaten erreicht werden.

Schlussfolgerung Die negativen Auswirkungen der COVID-19-Pandemie treffen vorwiegend die Klinik für Gynäkologie. Durch das Vertrauen in die Sicherheit der universitären Versorgung
und das Serviceangebot, werdende Väter nach Schnelltestung am Geburtsprozess teilhaben zu lassen, konnte eine Fallzunahme in der Geburtshilfe erreicht werden. Die Rückkehr zu präpandemischen
Leistungsniveaus gestaltet sich weiterhin schleppend, während sich der ohnehin weniger betroffene ambulante Sektor zügiger erholt. Der standortbezogene Rückgang der Diagnosen C50 und C56 ist
besorgniserregend und bedarf epidemiologischer Aufarbeitung. Die fallzahlbezogenen Auswirkungen der Pandemie bilden sich gleichsam in den ökonomischen Leistungskennzahlen ab.
The Effect of Multichannel and Channel-Free Hearing Aids on Spectral-Temporal Resolution and Speech Understanding in Noise
Authors: Kılıç Mert , Kara Eyyup
Published: April 2022

Abstract Background Identifying and understanding speech is difficult for individuals with sensorineural hearing loss, especially in noisy environments. Possible causes include less audibility of the signal, impaired temporal resolution, and low selectivity of
frequency. The hearing aid is the most common option used to minimize the problems faced by individuals with sensorineural hearing loss. Purpose This article investigates the effects of multichannel and channel-free hearing aid signal processing techniques on spectral-temporal
resolution and speech understanding in noise. Research Design An experimental study was used in which the determined tests were applied to the participants. Study Sample Thirty-four individuals with bilateral symmetrical sensorineural hearing loss between the
ages of 18 and 70 were included in our study. Data Collection and Analysis Spectral-temporally modulated ripple test, random gap detection test (RGDT), and Turkish matrix test were applied to the participants using multichannel and channel-free hearing aids. All the data obtained
were compared statistically in terms of the performances of the hearing aids. Results There was no significant difference between multichannel and channel-free hearing aids for spectral resolution and speech understanding in noise tests (p > 0.05). While
there was no significant difference between the two hearing aids for 500 and 4,000 Hz RGDT in temporal resolution measurement (p > 0.05), for 1,000 Hz (p = 0.045), 2,000 Hz (p = 0.046), and composite RGDT
(p = 0.001), statistically significant better performances were obtained with the channel-free hearing aids. Conclusion It is thought that faster processing of the incoming signal in the channel-free hearing aids improves the temporal resolution performance.
It is predicted that our study findings might help to determine the signal processing technique that will maximize the communication skills of the patients in various conditions.
Frequency-Following Response: Effects of Interaural Time and Intensity Differences
Authors: Ballachanda Bopanna B. , Moushegian George
Published: April 2022

This research investigated whether brainstem neural mechanisms that mediate lateralization of sounds can be extracted from the frequency-following response (FFR). Monaural and binaural FFRs were obtained from normal-hearing subjects to low-frequency (500 Hz) linearly gated tone bursts (4-4-4 msec) at 40, 50, and 60 dB SL and four interaural time differences (ITDs) (0, 333, 500, and 667 μsec). FFRs were also recorded to ITDs and intensity presented in concert and in opposition (lateralization stimuli). The results show that overall intensity and interaural time differentially affect the FFR. The FFRs evoked by ITDs and intensity (in concert and in opposition) are strikingly different. The normalized amplitudes of the binaural interaction component (BIC) are minimally altered by ITDs and intensity. The study presents strong evidence that ITDs of 0, 333, 500, and 667 μsec and lateralization stimuli, easily discriminated perceptually, evoke clearly distinguishable FFR waveforms. These ITDs provide the cues that mammals use to localize sound in a freefield. The BIC is essentially unaffected by overall intensity, ITDs, and lateralization stimuli. Based on the findings of this study, the FFR has the potential to become a tool for identification of normal and abnormal binaural processing at lower brainstem levels.

Abbreviations: ABR = auditory brainstem response, BIC = binaural interaction component, EEC = electroencephalographic, FFR = frequency-following response, IID = interaural intensity difference, ILD = interaural level difference, ITD = interaural time difference
Application of ImPASS to translated images produces image resolution below the optical diffraction resolution limit
Authors: Caron James N.
Published: April 2022

The image resolution produced by a lens/camera system is limited by the digital sampling frequency of the sensor and the diffraction limit as imposed by the front aperture diameter of the optics. A previous study using Image Phase Alignment Super-Sampling (ImPASS) demonstrated that Fourier phase information from a sequence of slightly displaced images can be used to achieve image resolution beyond the digital sampling frequency. In continuation of that work, this study applies ImPASS to sequences of slightly displaced empirical images for a range of aperture settings. The frames are up-sampled, aligned, and combined into a single frame. Application of Self-Deconvolving Data Restoration Algorithm (SeDDaRA) deconvolution reveals features with higher resolution. The slanted edge technique is applied to the processed images to establish the angular resolution of the system as a function of the effective f-number. When compared to Abbe’s resolution criteria, the measurements reveal that this super-sampling method produces image resolution that subceeds the diffraction limit of the lens/camera system.
Impact of azimuthal forcing on the Brillouin limit in a collisional two-species Ohkawa filter
Authors: Nicolas Timothée
Published: April 2022

This paper investigates the physics of plasma separation in a two species rotating collisional Ohkawa filter, when the source of rotation is an orbital angular momentum carrying wave. The electric field is treated self-consistently with ion and electron radial motion. The injection of angular momentum causes radial currents leading to charge penetration and electric field build up. The electric field varies until an equilibrium with the friction forces is reached. Both collisions with neutrals and Coulomb collisions are considered. In the case where the electric field is driven by the resonant wave, there is no collisional breakdown of the Brillouin limit [Rax et al., Phys. Plasmas 22, 092101 (2015)]; on the contrary, the maximum achievable electric field decreases when the collision frequency is increased. When two species are present, one that undergoes the wave forcing while the second does not interact with the wave, we find the following: the first species is confined, while the second species can be expelled or confined depending on the charge to mass ratio and the collisionalities. Assuming equal charge numbers, if the second species is the heavy one, it is always expelled, which is a standard result. When the second species is the light one, it can also be expelled in the common case where neutral collisions dominate over Coulomb collisions, which constitutes a new result.
Boundary conditions for isolated asymptotically anti-de Sitter spacetimes
Authors: de Oliveira Christyan C. , Mosna Ricardo A. , Pitelli João Paulo M.
Published: April 2022

We revisit the propagation of classical scalar fields in a spacetime, which is asymptotically anti-de Sitter. The lack of global hyperbolicity of the underlying background gives rise to an ambiguity in the dynamical evolution of solutions of the wave equation, requiring the prescription of extra boundary conditions at the conformal infinity to be fixed. We show that the only boundary conditions that are compatible with the hypothesis that the system is isolated, as defined by the (improved) energy–momentum tensor, are of Dirichlet and Neumann types.
Influence of diffusive transport on ultrafast magnetization dynamics
Authors: Ashok Sanjay , Seibel Christopher , Weber Sebastian T. , Briones Johan , Rethfeld Baerbel
Published: April 2022

We study the influence of transport effects on time- and space-resolved magnetization dynamics in a laser-excited thick nickel film. We explicitly include diffusive heat transport and spin-resolved charge transport as well as Seebeck and Peltier effects and calculate the dynamics of spin-dependent electronic temperatures, chemical potentials, lattice temperatures, and magnetization. We find that transport has an influence on the magnetization dynamics closer to the excited surface as well as in regions deeper than the penetration depth of the laser. We reveal that, for higher absorbed fluences and in the presence of transport, thick magnetic films show a quenching time nearly independent of depth, though the magnitude of quenching is depth-dependent.
Gradient-driven turbulence in Texas Helimak
Authors: Toufen D. L. , Pereira F. A. C. , Guimarães-Filho Z. O. , Caldas I. L. , Gentle K. W.
Published: April 2022

We investigate the turbulence level dependence on plasma profiles in experiments in Texas Helimak, a toroidal basic plasma device, with long stable electron cyclotron resonant heating (ECRH) discharges and great flexibility to alter the equilibrium magnetic field. A large set of Langmuir probes is used to obtain the turbulence level and also the plasma radial profiles for several magnetic field intensities with the same safety factor and field line pitch profiles. As a consequence of the ECRH heating, changing the toroidal magnetic field, the equilibrium density profiles are radially displaced. For all the analyzed discharges, with constant magnetic field curvature and shear profiles, we verify that the plasma turbulence has a critical dependence on the equilibrium density profile. Namely, radial regions with negative density radial gradient, i.e., in the opposite direction of the magnetic curvature, present high turbulence level. By properly comparing the turbulence radial profiles with the density peak position, we show that the negative density gradient is the main cause of high amplitude turbulence, in agreement with predictions for ideal interchange modes. Furthermore, intermittence analysis shows that the extreme events (bursts) contribution for the probability density functions (PDFs) is also related to the relative position with respect to the density peak, and that the turbulence level enhancement is likely due to the increase in burst occurrence.
Spatial distribution and transport mechanism of electrons in large and powerful inductively coupled plasma sources with Faraday shield
Authors: Wang Qiang , Chen Chao , Cui Yun-Qiu , Niu Chun-Jie , Liu Wei-Feng , Lei Guang-jiu , Lu Na , Liu Dong-Ping
Published: April 2022

A large and powerful radio frequency (RF) inductively coupled plasma (ICP) source with a Faraday shield (FS) has been investigated by a 3D fluid model, consisting of a plasma module and an electromagnetic field module. Effects of the structure of the FS, the RF current, and the gas pressure on the spatial distributions of plasma parameters including the electron density, electron temperature, and electron potential barrier are investigated systematically. The results show that the FS has a great influence on the spatial distribution and transport mechanism of electrons. The electron density has a maximum value at the center of the ICP source and declines sharply near the FS. Furthermore, it decreases obviously with the decreasing slit width, due to the electron transport mechanism, which is directly related to the electron potential barrier and electron temperature. In addition, the electron density increases with the RF current and gas pressure; it is noteworthy that the stronger induced electric field heating exists at the slit gap under high RF current that makes the electron temperature increase. The data obtained in this paper could lead to a deeper insight into the characteristics of ICP sources, which is extremely essential for optimizing the FS structure and designing large and powerful radio frequency ICPs in the future.
Efficient charge separation and enhanced photocurrent of CdTe quantum dots-Au nanoclusters composite with type-II band alignment
Authors: Xu Jia , Pan Yatao , Wei Zhongran , Luo Shida , Ran Xia , He Yulu , Liu Renming , Chi Zhen , Guo Lijun
Published: April 2022

Quantum dots (QDs)-based composites are promising candidates for optoelectronic and photonic devices. Understanding the photo-induced carrier dynamics is fundamental and crucial for improving the photoelectric conversion efficiency of nanocomposites. In this work, we have constructed nanocomposite hybridizing CdTe QDs with Au nanoclusters (Au NCs) and investigated the ultrafast carrier dynamics and enhanced photoelectric properties. The concurrent photoluminescence quenching and lifetime decreasing of CdTe QDs and Au NCs suggest a type-II band alignment, facilitating the carrier dynamics in the CdTe QDs-Au NCs' nanocomposite. The transient absorption measurements demonstrate an ultrafast and efficient electron transfer from CdTe QDs to Au NCs, effectively promoting the charge separation and inhibiting the exciton recombination. We found that the quantum efficiency of hot electron transfer can reach ∼50% with a rate constant of 1.01 × 1013 s−1 for the CdTe QDs-Au NCs' nanocomposite. As a result, the photocurrent performance of the CdTe QDs-Au NC device has been dramatically enhanced due to the efficient separation of photogenerated carriers, compared to that of individual CdTe QDs and Au NCs. These findings are significant for developing the light-harvesting and photoelectric devices based on semiconductor QDs and metal NCs.
Timing jitter of monodisperse droplets generated by capillary jet breakup
Authors: She Lei , Fang Yanshen , Hu Liang , Su Rui , Fu Xin
Published: April 2022

Uniform droplets generated by Rayleigh breakup of liquid jet are widely applied in science and engineering. The droplets are produced by imposing a periodic velocity perturbation on a micro-sized liquid jet. In practical situations, the frequency of droplet generation is not perfectly steady like the preset perturbation frequency. This unwanted timing jitter poses kinds of problems. We studied the fluid mechanism of the jitter at short working distance and its dependence on various parameters. We found that at short distance, the jitter is mainly affected by the reduction rather than the dispersion in the droplet velocity. The magnitude of the jitter is related to the velocity reduction and the unsteadiness of the perturbation. The velocity difference between the droplet and the jet is analytically obtained based on one-dimensional linear analysis of drop formation in liquid jet, and numerical simulations validate the results. The influence of the unsteady perturbation is explained by the evolution of control volumes with different initial amplitudes. The degree of jitter is finally deduced, and its relationships with each variable are compared with experiments. Optimization methods are given to mitigate jitter by adjusting the perturbation parameters and jet properties.
A measure–correlate–predict model based on neural networks and frozen flow hypothesis for wind resource assessment
Authors: Chen Danyang , Zhou Zhideng , Yang Xiaolei
Published: April 2022

In this paper, a measure–correlate–predict (MCP) model based on neural networks (NN) and frozen flow hypothesis, which is abbreviated as the MCPNN-frozen model, is proposed for wind resource assessment and tested using turbulent channel flows with three different surface roughness lengths, i.e., k0=0.001, 0.01, and 0.1 m. The predictions from the MCPNN-frozen model are compared with the real data for different separations (s) between the reference point and the target point. The results show that the correlation coefficients C.C. between the model predictions and real data are roughly higher than 0.5 for small separations s/δ≤3 (where δ is the boundary layer thickness), and the coefficients of determination (R2) are approximately higher than 0.3 when s/δ≤2. The generalization capacity of the MCPNN-frozen model is tested for different roughness lengths and different velocity components. Further analyses show that, even though C.C. and R2 decrease when increasing s, the large-scale variations of velocity fluctuations are well captured by the MCPNN-frozen model especially for the one trained using the data filtered in time. Furthermore, it is found that the model trained using the filtered data without a spanwise offset can well predict the large-scale variations at the target point when the spanwise offsets between the target point and the reference point are small (e.g., 0.1δ and 0.2δ). The proposed model leverages the power of neural networks and physical understanding. Further development of the model for complex scenarios will be carried out in the future work.
Edge wetting: Steady state of rivulets in wedges
Authors: Kubochkin Nikolai , Gambaryan-Roisman Tatiana
Published: April 2022

The geometry of rough, textured, fractured, and porous media is topologically complicated. Such media are commonly modeled as bundles of capillary tubes. However, angle-containing geometries can serve as a more realistic portrayal of their internal structure. A basic element inherent to all of these media is an open wedge-like channel. The classical theory of capillarity ignoring intermolecular interactions implies that liquid entering a wedge must propagate indefinitely along its spine when the liquid–gas interface is concave. This is well known as the Concus–Finn condition. In the present paper, we show that steady-state rivulets can be formed in such channels when surface forces are taken into account. We present a simple model based on the disjoining pressure approach and analyze the shape of rivulets in wedges. We also consider the case when the walls of the wedge are soft and can be deformed by the liquid.
Closed vortex filament in a cylindrical domain: Circulation quantization
Authors: Talalov S. V.
Published: April 2022

This article investigates quantum oscillations of a vortex ring with zero thickness that evolves in a cylindrical domain V=D×[0,L]. The symbol D denotes the planar domain, which is bounded by some closed connected curve S. The quantization scheme of this dynamical system is based on the approach proposed by the author earlier [“Small oscillations of a vortex ring: Hamiltonian formalism and quantization,” Eur. J. Mech. B/Fluids 92, 100–106 (2022); arXiv:Math-ph/2112.04859v1]. As result, we find the discrete values Γn for circulation Γ. In contrast to the traditional approach where such quantities are usually postulated, the values Γn are deduced rigorously as the consequence of the conventional scheme of quantum theory. The model demonstrates the splitting of levels also. In particular, the levels correction values depend on the domain V: both the cylinder height L and the form of the curve S affect the final formula for the quantities Γn. Moreover, we prove that the basic circulation levels demonstrate a “fine structure.” These anomalous terms, which are proportional to the value ℏ2, are calculated in the article as well. The conclusions are compared with some results of numerical simulations by other authors “Intermittency of velocity circulation in quantum turbulence,” Phys. Rev. X 11, 011053 (2021).
Single-element real-time interferometric system for measuring dynamic temperature field of liquid medium
Authors: Wang Chi , Xie Xiangyu , Zhang Hang , Peng Zhiqing , Yang Mochou , Zhang Xia , Feng Guoying
Published: April 2022

Temperature plays an important role in biomedicine and industrial production. In this study, we demonstrate a simple and reliable real-time interferometric system based on a single-element for measuring the dynamic temperature field of liquid media. In the proposed system, the reference beam and the object beam enter the beam splitter cube with a splitting ratio of 50:50 to produce interference fringes. The interference light arrives at the observation plane of a CMOS camera after being attenuated, which is capable of monitoring the change process of space carrier phase shift distribution in real time. The common optical path design eliminates the environmental disturbance. The phase shift of the interferograms as the optical path difference between the reference beam passing through liquid and the object beam passing through air is calculated by fast Fourier transform. The temperature changes of 50% polyacrylamide hydrogel (25–65 °C), 4% NaCl (25–65 °C), and ethanol (20–60 °C) were measured by our proposed system. During the experiment, we successfully measured the dynamically changing temperature field of deionized water subjected to a heating and cooling process (25–40 °C). The proposed system offers the advantages of compact structure, high efficiency, long-term stability, and low cost, and it is expected to assist non-contact measurements and biomedical research, making it a viable reference candidate for the field of environmental ecology and medicine.
Analysis of turbulence generation and dissipation in shear layers of methane–oxygen diffusion flames using direct numerical simulations
Authors: Martinez-Sanchis Daniel , Banik Sagnik , Sternin Andrej , Sternin Daniel , Haidn Oskar , Tajmar Martin
Published: April 2022

A turbulent methane–oxygen diffusion flame is studied using a direct numerical simulation setup. The operating regime and turbulence characteristics are chosen to resemble those of a modern methane rocket combustor. Local flame characteristics and dimensionless numbers are defined and evaluated, and their relationship with the turbulent kinetic energy transport budget is studied. Positive net turbulence generation is observed in the reaction shear layer. It is found that the underlying mechanisms for these results are similar to those encountered in premixed flames, with pressure terms acting as the primary turbulent kinetic energy sources. Models for predicting turbulent transport through mean pressure gradients, fluctuating pressure gradients, and turbulent flux of turbulent kinetic energy are adapted. The accuracy of the proposed formulations is assessed, and the involved challenges are discussed.
Study on corrosion resistance of AlCuxNiTiZr multi-principal element alloy films in NaCl solution
Authors: Huang Kai , He Liangchun , Wang Shuaishuai , Li Huizheng , Chen Yigang , Guo Haibo
Published: April 2022

The corrosion resistance of multi-principal element alloy (MPEA) films is complex dependent on their composition. The purpose of this paper is to explain the relationship between the corrosion resistance and the Cu content of AlCuxNiTiZr MPEA films. AlCuxNiTiZr films were deposited by magnetron sputtering. Their corrosion resistance in 3.5 wt. % NaCl was studied by potentiodynamic polarization experiment and inductively coupled plasma emission spectroscopy. In this paper, the potentiodynamic polarization curve is analyzed from the perspective of corrosion type and corrosion control. Combined with x-ray photoelectron spectroscopy, the change in corrosion current density in AlCuxNiTiZr films is explained.
Effects of various inlet parameters on the computed flow development in a bidirectional vortex chamber
Authors: Sharma Gaurav , Majdalani Joseph
Published: April 2022

We vary the inflow properties in a finite-volume solver to investigate their effects on the computed cyclonic motion in a right-cylindrical vortex chamber. The latter comprises eight tangential injectors through which steady-state air is introduced under incompressible and inviscid conditions. To minimize cell skewness around injectors, a fine tetrahedral mesh is implemented first and then converted into polyhedral elements, namely, to improve convergence characteristics and precision. Once convergence is achieved, our principal variables are evaluated and compared using a range of inflow parameters. These include the tangential injector speed, count, diameter, and elevation. The resulting computations show that well-resolved numerical simulations can properly predict the forced vortex behavior that dominates in the core region as well as the free vortex tail that prevails radially outwardly, beyond the point of peak tangential speed. It is also shown that augmenting the mass influx by increasing the number of injectors, injector size, or average injection speed further amplifies the vortex strength and all peak velocities while shifting the mantle radially inwardly. Overall, the axial velocity is found to be the most sensitive to vertical displacements of the injection plane. By raising the injection plane to the top half portion of the chamber, the flow character is markedly altered, and an axially unidirectional vortex is engendered, particularly, with no upward motion or mantle formation. Conversely, the tangential and radial velocities are found to be axially independent and together with the pressure distribution prove to be the least sensitive to injection plane relocations.
Solvation shell thermodynamics of extended hydrophobic solutes in mixed solvents
Authors: Tripathy Madhusmita , Bharadwaj Swaminath , van der Vegt Nico F. A.
Published: April 2022

The ability of various cosolutes and cosolvents to enhance or quench solvent density fluctuations at solute–water interfaces has crucial implications on the conformational equilibrium of macromolecules such as polymers and proteins. Herein, we use an extended hydrophobic solute as a model system to study the effect of urea and methanol on the density fluctuations in the solute’s solvation shell and the resulting thermodynamics. On strengthening the solute–water/cosolute repulsive interaction, we observe distinct trends in the mutual affinities between various species in, and the thermodynamic properties of, the solvation shell. These trends strongly follow the respective trends in the preferential adsorption of urea and methanol: solute–water/cosolute repulsion strengthens, urea accumulation decreases, and methanol accumulation increases. Preferential accumulation of urea is found to quench the density fluctuations around the extended solute, leading to a decrease in the compressibility of the solvation shell. In contrast, methanol accumulation enhances the density fluctuations, leading to an increase in the compressibility. The mode of action of urea and methanol seems to be strongly coupled to their hydration behavior. The observations from this simple model is discussed in relation to urea driven swelling and methanol induced collapse of some well-known thermo-responsive polymers.
Early-life exposure to hardship increased risk tolerance and entrepreneurship in adulthood with gender differences
Authors: Yi Junjian , Chu Junhong , Png I. P. L.
Published: April 2022

Significance

We investigate the effect of hardship on entrepreneurship using China’s Great Famine as a quasinatural experiment. This yielded robust evidence that individuals who experienced more hardship were subsequently more likely to become entrepreneurs. Importantly, the increase in entrepreneurship was at least partly due to conditioning rather than selection. Regarding the behavioral mechanism, hardship was associated with greater risk tolerance among men and women but conditioned business ownership only among men. The gender differences were possibly due to a Chinese social norm that men focus on market work and women focus on domestic work combined with interspousal risk pooling in occupational choice.
Orientation anisotropies in macaque visual areas
Authors: Fang Chen , Cai Xingya , Lu Haidong D.
Published: April 2022

Significance

Orientation selectivity is one of the most important functional features of visual neurons. In the primate visual cortex, whether all orientations are represented equally is still unclear. Previous electrophysiological recordings led to controversial findings. By analyzing a large set of optical imaging data, we found anisotropic representations of orientation in macaque visual areas and that different areas had different types of anisotropies. These findings not only shed light on the long-standing question regarding a basic property of the primate visual cortex, but also on the strategy the visual system takes to represent and analyze the visual world.