bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of magneto-thermal coupling treatment on microstructure and texture of CGO steel
Authors: Dong Lili , Ma Yonglin , Liu Baozhi
Published: November 2022

The research object of this paper is the common oriented silicon steel (CGO) with Si content of 3.1%. The magneto-thermal coupling processing device independently developed was used to conduct laboratory studies on magneto-thermal coupling decarburization annealing, magneto-thermal coupling high temperature pre-annealing and magneto-thermal coupling tensile leveling annealing. The microstructure and macroscopic texture of CGO steel after magneto-thermal coupling treatment were measured by Zeiss microscope and X-ray diffrotometer, and compared with the samples after conventional annealing process. The results show that the magneto-thermal coupling treatment at the decarburization annealing stage can promote the distribution of ferritic grains along the magnetic field direction. The cubic texture {001}<100> with high level fault energy and {111}＜112＞ texture also increases. In the high temperature pretreatment stage, the increase of {111}＜112＞ texture is more obvious after magnetic-thermal coupling treatment. The deviation angle of goss-oriented grain decreases after magneto-thermal coupling treatment in tensile leveling stage. The magneto-thermal coupling effect plays a positive role in the microstructure and texture of CGO steel during decarburization annealing, high temperature pre-annealing and tensile leveling annealing.
One Dimensional Martingale Rearrangement Couplings
Authors: Jourdain B. , Margheriti W.
Published: November 2022

We are interested in martingale rearrangement couplings. As introduced by Wiesel in order to prove the stability of Martingale Optimal Transport problems, these are projections in adapted Wasserstein distance of couplings between two probability measures on the real line in the convex order onto the set of martingale couplings between these two marginals. In reason of the lack of relative compactness of the set of couplings with given marginals for the adapted Wasserstein topology, the existence of such a projection is not clear at all. Under a barycentre dispersion assumption on the original coupling which is in particular satisfied by the Hoeffding-Frechet or comonotone coupling, Wiesel gives a clear algorithmic construction of a martingale rearrangement when the marginals are finitely supported and then gets rid of the finite support assumption by relying on a rather messy limiting procedure to overcome the lack of relative compactness. Here, we give a direct general construction of a martingale rearrangement coupling under the barycentre dispersion assumption. This martingale rearrangement is obtained from the original coupling by an approach similar to the construction we gave in Jourdain and Margheriti [Electr. J. Probab. (2020)] of the inverse transform martingale coupling, a member of a family of martingale couplings close to the Hoeffding-Fréchet coupling, but for a slightly different injection in the set of extended couplings introduced by Beiglböck and Juillet and which involve the uniform distribution on [0,1] in addition to the two marginals. We last discuss the stability in adapted Wassertein distance of the inverse transform martingale coupling with respect to the marginal distributions.
Das wachsende Interesse an Breast Implant Illness und dessen Einfluss
auf das Verhalten der Patientinnen
Authors: Weitkunat Adina , Targosinski Stefan , Bauer Benedikt , Grünert Jörg G. , Winsauer Stefan
Published: November 2022

Breast Implant Illness (BII) bezeichnet eine Reihe von unspezifischen,
systemischen Symptomen, von denen angenommen wird, dass sie mit Brustimplantaten
in Verbindung stehen. Zu den BII-Symptomen gehören unter anderem
Müdigkeit, Haarausfall, Hautausschläge, oder chronische
Schmerzen. Schlüssige Beweise für einen kausalen Zusammenhang
zwischen Silikonimplantaten und BII fehlen jedoch nach wie vor. In Anbetracht
der jüngsten Erkenntnisse, dass texturierte Implantate in seltenen
Fällen zu einem Brustimplantat-assoziierten, anaplastischen
Großzell-Lymphom (BIA-ALCL) führen können, ist ein
möglicher Zusammenhang zwischen Brustimplantaten und BII denkbar und
rechtfertigt weitere Untersuchungen. Wir beobachten eine steigende Anzahl von
Patientinnen, die aufgrund systemischer Symptome im Zusammenhang mit
Brustimplantaten Beratung und Behandlung ersuchen, was sich in einem zunehmenden
Interesse in der Literatur und den sozialen Medien widerspiegelt. Das Ziel
dieser Arbeit war es, das wachsende Interesse an BII zu untersuchen. Wir
beschreiben die klinischen Merkmale einer Patientin, die unter Symptomen leidet,
die mit BII vereinbar sind und kontextualisieren die klinische
Präsentation mit der aktuellen Datenlage.
Keine Interdisziplinarität ohne Interprofessionalität in der Schmerztherapie
Authors: Brinkers Michael , Pfau Giselher , Voigt Anett , Brodowski Steffen , Meyer Frank
Published: November 2022

Am Beispiel der Psychiatrie zeigt sich eindrucksvoll, dass ein Missverhältnis zwischen der niedrigen Zahl von Konsilen und der drei- bis 15-fach höheren Zahl an Patienten mit psychischen Störungen in einem Allgemeinkrankenhaus besteht. Das gleiche Problem besteht auch in der Schmerztherapie. Die Auflösung dieses Missverhältnisses könnte zu einer besseren Patientenversorgung in den verschiedensten Bereichen der klinischen Medizin beitragen. Ein Arbeitsmodell aus der Schmerztherapie zeigt mögliche Wege auf.
Prevention of Dental Biofilm Formation with Polyphenols: A Systematic Review
Authors: Schestakow Anton , Meyer-Probst Clara Theres , Hannig Christian , Hannig Matthias
Published: November 2022

Polyphenols are plant secondary products with health-promoting properties against various degenerative or infectious diseases, and thus may help in the prevention of oral diseases. The aim of the present systematic review was to investigate polyphenols as a possible adjuvant in inhibiting dental biofilm formation, which is an important precondition for the most prevalent oral disease – caries and periodontitis. A literature search was conducted using the databases PubMed, CENTRAL and Scopus. Only studies with oral healthy participants and plaque level as outcome were included. Data search and extraction was conducted by two authors independently. Of the 211 initially identified studies, only six met all inclusion criteria. Meta-analysis was performed with five studies using the random effect model. Treatment with polyphenols reduced the plaque level in comparison to a negative control, but not significantly. Strong evidence of heterogeneity was observed. The diversity and complexity of polyphenols and their preparation need to be considered. There is no clear evidence that clinical use of polyphenols can prevent dental biofilm formation. Additional research with more and larger randomized controlled trials are required.
Dynamics of Earth's bow shock under near-radial interplanetary magnetic field conditions
Authors: Pollock C. J. , Chen L.-J. , Schwartz S. J. , Wang S. , Avanov L. , Burch J. L. , Gershman D. J. , Giles B. L. , Raptis S. , Russell C. T.
Published: November 2022

We investigate the dynamics of Earth's quasi-parallel terrestrial bow shock based on measurements from the Magnetospheric MultiScale (MMS) spacecraft constellation during a period of near-radial interplanetary magnetic conditions, when the interplanetary magnetic field and the solar wind (SW) velocity are nearly anti-parallel. High-speed earthward ion flows with properties that are similar to those of the pristine SW are observed to be embedded within the magnetosheath-like plasma. These flows are accompanied by Interplanetary Magnetic Field (IMF) intensity of less than about 10 nT, compared to nearby magnetosheath intensities of generally greater than 10 nT. The high-speed flow intervals are bounded at their leading and trailing edges by intense fluxes of more energetic ions and large amplitude quasi-sinusoidal magnetic oscillations, similar to ultra-low frequency waves known to steepen and pileup on approach toward Earth to form the quasi-parallel bow shock. The MMS string-of-pearls configuration is aligned with the outbound trajectory and provides inter-spacecraft separations of several hundred km along its near 103 length, allowing sequential observation of the plasma and magnetic field signatures during the event by the four spacecraft. The SW-like interval is most distinct at the outer-most MMS-2 and sequentially less distinct at each of the trailing MMS spacecraft. We discuss the interpretation of this event alternatively as MMS having observed a quasi-rigid bow shock contraction/expansion cycle, ripples or undulations propagating on the bow shock surface, or a more spatially local evolution in the context of either a deeply deformed shock surface or a porous shock surface, as in the three-dimensional patchwork concept of the quasi-parallel bow shock, under the extant near-radial IMF condition.
Electron temperature relaxation in the clusterized ultracold plasmas
Authors: Dumin Yurii V. , Lukashenko Anastasiia T.
Published: November 2022

Ultracold plasmas are a promising candidate for the creation of strongly coupled Coulomb systems. Unfortunately, the values of the coupling parameter Γe actually achieved after photoionization of the neutral atoms remain relatively small because of the considerable intrinsic heating of the electrons. A conceivable way to get around this obstacle might be to utilize a spontaneous ionization of the ultracold Rydberg gas, where the initial kinetic energies could be much less. However, the spontaneous avalanche ionization will result in a very inhomogeneous distribution (clusterization) of the ions, which can change the efficiency of the electron relaxation in the vicinity of such clusters substantially. In the present work, this hypothesis is tested by an extensive set of numerical simulations. As a result, it is found that despite a less initial kinetic energy, the subsequent relaxation of the electron velocities in the clusterized plasmas proceeds much more violently than in the case of the statistically uniform ionic distribution. The electron temperature, first, experiences a sharp initial jump (presumably, caused by the “virialization” of energies of the charged particles) and, second, exhibits a gradual subsequent increase (presumably, associated with a multi-particle recombination of the electrons at the ionic clusters). As a possible tool to reduce the anomalous temperature increase, we also considered a two-step plasma formation, involving the blockaded Rydberg states. This leads to a suppression of the clusterization due to a quasi-regular distribution of ions. In such a case, according to the numerical simulations, the subsequent evolution of the electron temperature proceeds more gently, approximately with the same rate as in the statistically uniform ionic distribution.
The fuzzy control of electrohydrodynamic direct writing
Authors: Kang Guoyi , Chen Huatan , Jiang Jiaxin , Zheng Jianyi , Wang Xiang , Li Wenwang , Cheng Xiang , Fang Zheng , Zheng Gaofeng
Published: November 2022

The electrohydrodynamic direct-writing (EDW) technology has been widely used in the integration of micro-/nano-systems. However, the complex model is a critical obstacle for the uniformity and controllability of the EDW fiber. It is difficult to gain an appropriate control strategy for position accuracy and the industrial application of EDW technology. Fuzzy control has a significant effect on objects in which the mathematical models are complex and the dynamic characteristics are difficult to capture. In this paper, the integrated fuzzy control method based on the jet mode and the electrospinning current was designed for the EDW system, and four groups of experiments were set up in different control schemes: the open-loop control, the current control, the jet mode control, and the integrated control. With the integrated control, the volatility percentage of the fiber spacing decreased from 23% to 9.7%, and the volatility percentage of the electrospinning current decreased from 35% to 14%. The fuzzy control shows dramatic effects on the uniformity and the deposition precision of the EDW fibers, which will extend the fields of application of EDW.
Effect of negatively biased electrode on two ion species plasma–wall transition, ion drag force, and levitation of dust particle
Authors: Basnet Suresh , Thapa Shiva Bikram , Maskey Anish , Khanal Raju
Published: November 2022

The effect of negatively biased electrodes on two ion species (argon and xenon) magnetized plasma–wall transition characteristics and the levitation of an isolated dust particle in the sheath region has been investigated using the kinetic trajectory simulation method based on a kinetic theory. It is found that the electrode biasing affects the transition parameters: space charge density, sheath potential, evolution of phase-space, and particle flux toward the electrode. The scale length of the Debye sheath region becomes widened for the increase in negative biasing and the presence of magnetic field as well. The biasing voltage and size of the dust particle have significant effect on the evolution of the dust charge, ion drag force, and levitation of a charged dust grain in the transition region. The dust particle is negatively charged at the particle injection side, and it acquires a positive charge for higher biasing voltage close to the electrode owing to electron depletion in that region. The distance of stable levitation from the electrode increases with the increase in the negative voltage applied to the electrode. Furthermore, the volumetric composition of two species of positive ions influence the dust charging process with the negative charge of the dust particle increasing as the concentration of xenon ions increases.
On the properties of Alfvénic switchbacks in the expanding solar wind: The influence of the Parker spiral
Authors: Squire Jonathan , Johnston Zade , Mallet Alfred , Meyrand Romain
Published: November 2022

Switchbacks—rapid, large deflections of the solar wind's magnetic field—have generated interest as possible signatures of the mechanisms that heat the corona and accelerate the solar wind. In this context, an important task for theories of switchback formation and evolution is to understand their observable distinguishing features, allowing them to be carefully assessed using spacecraft data. Here, we work toward this goal by studying how Alfvénic switchbacks evolve in the expanding solar wind beyond the Alfvén radius, when the background magnetic field also rotates due to the Parker spiral. Using simple analytic arguments based on the physics of one-dimensional spherically polarized (constant-field-magnitude) Alfvén waves, we find that, by controlling the wave's obliquity, a Parker spiral strongly impacts switchback properties. Surprisingly, parallel magnetic-field deflections (switchbacks) can grow faster in a Parker spiral than in a radial background field, even though normalized wave amplitudes grow more slowly. In addition, switchbacks become strongly asymmetric: large switchbacks preferentially involve magnetic-field rotations in the plane of the Parker spiral (tangential deflections) rather than perpendicular (normal) rotations, and such deflections are strongly “tangentially skewed,” meaning switchbacks always involve field rotations in the same direction (toward the positive-radial direction for an outward mean field). In a companion paper [Johnston et al., Phys. Plasmas 29, 072902 1346 (2022)], we show that these properties also occur in turbulent 3D fields with switchbacks, given various caveats. Given that these nontrivial asymmetries and correlations develop purely as a consequence of switchback propagation in the solar wind, our results show that in situ observed asymmetrical switchback features cannot be used straightforwardly to infer properties of sources in the low corona.
Feasibility study of a high spatial and time resolution beam emission spectroscopy diagnostic for localized density fluctuation measurements in Lithium Tokamak eXperiment-β (LTX-β)
Authors: Banerjee Santanu , Boyle D. P. , Maan A. , Majeski R. , Kaita R. , Smith D. , von Hellermann M. , Hansen C. , Capecchi W. , Elliott D.
Published: November 2022

Trapped electron mode (TEM) is the main source of turbulence predicted for the unique operation regime of a flat temperature profile under low-recycling conditions in the LTX-β tokamak, while ion temperature gradient driven turbulence may also occur with gas fueling from the edge. To investigate mainly TEM scale density fluctuations, a high spatial and time resolution 2D beam emission spectroscopy (BES) diagnostic is being developed. Apart from spatially localized density turbulence measurement, BES can provide turbulence flow and flow shear dynamics. This BES system will be realized using an avalanche photodiode-based camera and narrow band interference filter. The system can acquire data at 2 MHz. Simulations with the Simulation of Spectra (SOS) code indicate that a high signal to noise ratio can be achieved with the proposed system. This will enable sampling the density fluctuations at this high time resolution. The design considerations and system optimization using the SOS code are presented.
Influences of thermal physical property parameters on operating characteristics of simulated rotating detonation ramjet fueled by C12H23
Authors: Yan Chenglong , Shu Chen , Zhao Jiafeng , Su Lingyu , Tong Yiheng , Xie Qiaofeng , Lin Wei
Published: November 2022

Two-phase rotating detonation ramjets are considered to be suitable for aerospace applications due to their high thermodynamic cycle efficiency. These engines have an extremely complex internal flow field, in which the liquid fuel undergoes physical and chemical processes such as fragmentation, evaporation, mixing, and combustion; these processes also interact with detonation waves that have significant gradients. This makes it difficult to simulate a three-dimensional (3D) full-process rotating detonation combustion chamber. Here, based on the Euler–Lagrangian simulation method, a 3D numerical combustion chamber was simulated using kinetic theory and the constant thermal physical property parameter (TPPP) calculation method. The accuracy of these methods was then compared with the existing experimental results and theoretical values. Calculating the TPPPs using kinetic theory brought about a relatively high-pressure peak and detonation wave temperature; the detonation wave profile was also finer and more precise. The detonation wave propagation velocity of the two-phase detonation is estimated to be about 60% of the theoretical gas-phase CJ velocity. The calculation method of physical parameters has relatively little influence on the engine’s operating frequency and the detonation wave's propagation velocity but has a more significant influence on the peak pressure. Constant TPPPs can be used when the Kelvin–Helmholtz–Rayleigh–Taylor model with insufficient precision is used to consider the breakup of droplets and leads to the acceleration of the propagation speed of two-phase detonation waves.
Stacking order reduction in multilayer graphene by inserting nanospacers
Authors: Xu Zizhao , Inoue Taiki , Nishina Yuta , Kobayashi Yoshihiro
Published: November 2022

Toward macroscopic applications of graphene, it is desirable to preserve the superior properties of single-layer graphene in bulk scale. However, the AB-stacking structure is thermodynamically favored for multilayer graphene and causes strong interlayer interactions, resulting in property degradation. A promising approach to prevent the strong interlayer interaction is the staking order reduction of graphene, where the graphene layers are rotated in-plane to form a randomly stacking structure. In this study, we propose a strategy to effectively decrease the stacking order of multilayer graphene by incorporating nanospacers, cellulose nanofibers, or nano-diamonds (NDs) in the formation process of porous graphene sponges. We conducted an ultrahigh temperature treatment at 1500 °C with ethanol vapor for the reduction and structural repair of graphene oxide sponges with different concentrations of the nanospacers. Raman spectroscopy indicated an obvious increase in the random-stacking fraction of graphene by adding the nanospacers. The x-ray diffraction (XRD) analysis revealed that a small amount of the nanospacers induced a remarkable decrease in ordered graphene crystalline size in the stacking direction. It was also confirmed that a layer-number increase during the thermal treatment was suppressed by the nanospacers. The increase in the random-stacking fraction is attributed to the efficient formation of randomly rotated graphene through the ethanol-mediated structural restoration of relatively thin layers induced by the nanospacers. This stacking-order-reduced graphene with bulk scale is expected to be used in macroscopic applications, such as electrode materials and wearable devices.
Formation of oriented layered MoS2 from amorphous thin film revealed by polarized x-ray absorption spectroscopy
Authors: Krbal M. , Prikryl J. , Prokop V. , Pis I. , Bondino F. , Kolobov A. V.
Published: November 2022

MoS2 is a prototypical two-dimensional van der Waals (vdW) solid, where covalently bonded S–Mo–S triplets are held together by weaker vdW forces. In this work, we have studied structural transformation from a three-dimensional amorphous phase of MoS2 into a layered vdW crystal using S L2,3 edge x-ray absorption near-edge structure (XANES) spectroscopy with in-plane and out-of-plane polarized x-ray beam. The crystallization process, which starts from an isotropic amorphous phase, is accompanied by the establishment of vdW interaction between covalently bonded layers, resulting in the anisotropic nature of the crystalline phase. We have disclosed that the preferential growth of MoS2 layers along the (200) Bragg reflection commences immediately from the amorphous phase with no intermediate crystal orientations. We have additionally identified a unique signature in the S L2,3 edge spectrum that is associated with vdW bonds and can be possibly used to determine sulfur-based single-layered and multi-layered transition metal dichalcogenides.
Novel method and instrument for temperature-dependent tensile test of metallic materials without thermometers
Authors: Hua Yuyang , Li Shuo , Wang Xiaofeng , He Chunqing
Published: November 2022

A novel method for measuring temperature and conducting tensile tests of metallic wires at elevated temperatures is presented. Ohmic heating is used to elevate the sample temperature with a uniform distribution, which could vary from room temperature to its melting point. The temperatures of the wires in steady states are determined by using a heat transfer model without measuring directly by thermometers, which reduces the error introduced by contact temperature measurement or optical pyrometers. This technique for temperature measurement can be applied to measuring temperature-dependent electrical resistivity and conducting temperature-dependent tensile tests of metallic materials. A low-cost instrument was designed to conduct the tensile tests. In this work, temperature-dependent Young’s modulus, tensile strength at break, and the steady-state creep rate of 99.994%-pure Pb wires were further determined as applications of the tensile tests. The results show that the proposed method is valid and very useful for conducting temperature-dependent tensile tests of metallic materials.
Transport properties of polarization-induced 2D electron gases in epitaxial AlScN/GaN heterojunctions
Authors: Casamento Joseph , Nguyen Thai-Son , Cho Yongjin , Savant Chandrashekhar , Vasen Timothy , Afroz Shamima , Hannan Daniel , Xing Huili (Grace) , Jena Debdeep
Published: November 2022

AlScN is attractive as a lattice-matched epitaxial barrier layer for incorporation in GaN high electron mobility transistors due to its large dielectric constant and polarization. The transport properties of polarization-induced two-dimensional (2D) electron gas of densities of ∼2×1013/cm2 formed at the AlScN–GaN interface is studied by Hall-effect measurements down to cryogenic temperatures. The 2D electron gas densities exhibit mobilities limited to ∼300 cm2/V s down to 10 K at AlScN/GaN heterojunctions. The insertion of a ∼2 nm AlN interlayer boosts the room temperature mobility by more than five times from ∼300 cm2/V s to ∼1573 cm2/V s, and the 10 K mobility by more than 20 times to ∼6980 cm2/V s at 10 K. These measurements provide guidelines to the limits of electron conductivities of these highly polar heterostructures.
Design and characterization of a recoil ion momentum spectrometer for investigating molecular fragmentation dynamics upon MeV energy ion impact ionization
Authors: Duley Avijit , Tyagi Rohit , Bari Sandeep B. , Kelkar A. H.
Published: November 2022

We present the development and performance of a newly built recoil ion momentum spectrometer to study the fragmentation dynamics of ionized molecules. The spectrometer is based on the two-stage Wiley–McLaren geometry and satisfies both time and velocity focusing conditions. An electrostatic lens has been introduced in the drift region to achieve velocity imaging and higher angular collection. The spectrometer is equipped with a 2D position-sensitive detector with multi-hit coincidence electronics. Ionic fragments with kinetic energy ∼8 eV can be detected with 4π collection. The overall performance of the spectrometer has been tested by carrying out three-dimensional ion imaging measurements for diatomic (N2) and polyatomic (CH2Cl2) molecules under the impact of 1 MeV protons. Three-dimensional momentum and kinetic energy release distributions were derived from the measured position and time-of-flight spectra. The observed features of the various fragmentation channels as well as the measured kinetic energy release distributions are in complete agreement with the available data.
Two modes of vacuum flashover process under pulsed voltage
Authors: Xu Yao , Liu Zhigang , Zou Xiaobing , Wang Xinxin , Wang Peng
Published: November 2022

Vacuum flashover process can be influenced by various factors, such as gap length, applied voltage form, electric and magnetic field structures, and so on, leading to different flashover voltages and flashover times under a pulsed voltage. Particle-in-cell (PIC) simulation results in this paper show two typical vacuum flashover modes: (a) the area of high space charge density appears after electrons run across the gap and extends from the anode to cathode and (b) the area of high space charge density appears before electrons run across the gap and extends from the middle to both ends of the gap. In order to verify the PIC simulation results, a probe that measures the change in the electric field between the gap is embedded in the anode, the experimental waveform of which shows different features when the shape of insulator is different. Simulation results and experimental waveforms indicate that the flashover process of certain cylindrical insulators corresponds to the first mode, while the flashover process of certain conical insulators with an acute angle between the cathode and dielectric corresponds to the second mode.
Ferrimagnet based spin Hall detector of subterahertz frequency signals
Authors: Kozlova E. E. , Safin A. R. , Nikitov S. A.
Published: November 2022

A concept of a subterahertz (sub-THz) frequency range signals detector based on a ferrimagnet/normal metal (FiM/NM) heterostructure is proposed. An external linearly polarized electromagnetic (EM) wave excites precession in the FiM and spin pumping at the FiM/NM interface. The excited spin current in the NM converts into a direct current via the inverse spin Hall effect. We show that non-zero uncompensation between magnetic spins in FiM gives a non-zero output rectified voltage for both “easy axis” and “easy plane” uniaxial anisotropies. The increase in the uncompensation parameter removes degeneracy from two normal resonance modes and changes the sensitivity to the EM wave. Namely, the sensitivity of the higher mode increases, and the lower mode decreases with increasing the uncompensation parameter. We believe that our results can be helpful for the practical development of sub-THz frequency tunable resonance detector based on the FiM.
An integrated instrument of a tandem quadrupole mass spectrometer for cluster reaction and soft-landing deposition
Authors: Huang Benben , Wu Haiming , Yang Mengzhou , Luo Zhixun
Published: November 2022

We have developed an integrated instrument system of a multiple-ion laminar flow tube (MIFT) reactor combined with a tandem quadrupole mass spectrometer (TQMS) and soft-landing deposition (SD) apparatus. A customized water-cooling magnetron sputtering (MagS) source is designed, by which we are able to attain a highly efficient preparation of metal clusters of 1–30 atoms with tunable size distributions. Following the MagS source, a laminar flow tube reactor is designed, allowing for sufficient gas–collision reactions of the as-prepared metal clusters, which is advantageous for probing magic clusters and minimizing wall effects when probing the reaction dynamics of such clusters. The customized TQMS analyzer involves a conical octupole, two linear octupoles, a quadruple ion deflector, and a 19 mm quadruple mass analyzer, allowing to decrease the pressure stepwise (from ∼5 to ∼10−9 Torr), thus ensuring high sensitivity and high resolution of the mass spectrometry analysis. In addition, we have designed a dual SD apparatus for the mass-selected deposition of clusters and their reaction products. For the whole system, abbreviated as MagS-MIFT-TQMS-SD, we have performed a detailed ions-fly simulation and quantitatively estimated the ions transfer efficiency under vacuum conditions determined by real experiments. Taking these advantages, well-resolved Pbn+, Agn+, and Nbn+ clusters have been produced, allowing for meticulous studies of cluster reactions under sufficient gas-phase collisions free of electric field trapping. Also, we have tested the efficiency of the dual SD.
A portable spectroscopic instrument for multiplexed monitoring of acute water toxicity: Design, testing, and evaluation
Authors: Banerjee Amrita , Singh Soumendra , Ghosh Ria , Hasan Md. Nur , Bera Arpan , Roy Lopamudra , Bhattacharya Neha , Halder Animesh , Chattopadhyay Arpita , Mukhopadhyay Subhadipta , Das Amitava , Altass Hatem M. , Moussa Ziad , Ahmed Saleh A. , Pal Samir Kumar
Published: November 2022

The deteriorating water environment worldwide, mainly due to population explosion and uncontrolled direct disposal of harmful industrial and farming wastes, earnestly demands new approaches and accurate technologies to monitor water quality before consumption overcoming the shortcomings of the current methodologies. A spectroscopic water quality monitoring and early-warning instrument for evaluating acute water toxicity are the need of the hour. In this study, we have developed a prototype capable of the quantification of dissolved organic matter, dissolved chemicals, and suspended particulate matter in trace amounts dissolved in the water. The prototype estimates the water quality of the samples by measuring the absorbance, fluorescence, and scattering of the impurities simultaneously. The performance of the instrument was evaluated by detecting common water pollutants such as Benzopyrene, Crystal Violet, and Titanium di-oxide. The limit of detection values was found to be 0.50, 23.9, and 23.2 ppb (0.29 µM), respectively.
Intrinsic carrier losses in tellurium due to radiative and Auger recombinations
Authors: Hader Jörg , Liebscher Sven C. , Moloney Jerome V. , Koch Stephan W.
Published: November 2022

Fully microscopic many-body models based on inputs from first principles density functional theory are used to calculate the carrier losses due to radiative- and Auger-recombinations in bulk tellurium. It is shown that Auger processes dominate the losses for carrier densities in the range typical for applications as lasers. The Auger loss depends crucially on how far energetically lower hole bands are detuned from the valence band edge. Values for this detuning range throughout literature from being about equal to the bandgap to being on the order of 100 meV larger than the bandgap. We find that at cryogenic temperatures of 50 K (100 K), the Auger coefficient, C, is about six (three) orders of magnitude smaller if this detuning is as in our calculations at the low end of the published values rather than at the high end where it exceeds the bandgap. At room temperature, the sensitivity is reduced to about a factor of four with C values ranging between 0.4 and 1.6×10−27 cm6 s−1. Here, radiative losses dominate for carrier densities up to about 1016/ cm3 with a loss coefficient B≈10−11 cm3 s−1. The radiative losses are about two to three times lower than in typical bulk III–V materials for comparable wavelengths.
Activation imaging of drugs with hybrid Compton camera: A proof-of-concept study
Authors: Koshikawa N. , Omata A. , Masubuchi M. , Okazaki Y. , Kataoka J. , Matsunaga K. , Kato H. , Toyoshima A. , Wakabayashi Y. , Kobayashi T.
Published: November 2022

The visualization of drugs is essential for cancer treatment. Although several methods for visualizing drugs have been proposed, a versatile method that can be easily applied to various drugs has not yet been established. Therefore, we propose “activation imaging,” in which a drug is irradiated with thermal neutrons and becomes radioactive, enabling visualization using emitted x rays and/or gamma rays. Activation imaging does not require the conjugation of specific tracers with drugs. Therefore, it can be easily applied to a variety of drugs, drug carriers (e.g., metal nanoparticles), and contrast agents. In this study, neutron activation, gamma-ray spectroscopy, and imaging of drug carriers, anticancer drug, and contrast agents were performed. Gold nanoparticles (AuNPs) and platinum nanoparticles were used as drug carriers, cisplatin was used as an anticancer drug, and gadoteridol and iohexol were used as contrast agents. As a neutron source, the RIKEN accelerator-driven compact neutron source II (RANS-II) was utilized. The imaging was performed using a hybrid Compton camera (HCC). The HCC can visualize x rays and gamma rays ranging from a few keV to nearly 1 MeV, which enables the imaging of various x rays and gamma rays emitted from the activated drugs. As a result, the gamma-ray spectra indicated the generation of radioisotopes through neutron irradiation, and AuNPs and iohexol were visualized.
Room temperature skyrmions in symmetric multilayers
Authors: He Min , Li Jinzhi , Hu Chaoqun , Zhang Jine , Gao Yang , Li Zhuolin , Wang Xinran , Zhao Yinchang , Dai Zhenhong , Xiao Dongdong , Cai Jianwang , Zhang Ying
Published: November 2022

We experimentally demonstrate the generation of skyrmions (166 ± 42 nm) by controlling and modulating the skyrmion stability parameter κ through changing the Co layer thickness in the multilayer with repetitions of the symmetric Pt/Co/Pt trilayer. The magnetic field dependence of skyrmion evolution is reversible. Dzyaloshinskii–Moriya interaction constant D is quantitatively measured by Brillouin spectroscopy to understand the mechanism. Surprisingly, the D value is high enough to generate skyrmions in a symmetric sandwich structure although the value is smaller than that in an antisymmetric Pt/Co/Ta trilayer. The decreased D value with the increase in the Co layer thickness indicates that the Dzyaloshinskii–Moriya interaction is still contributed from the interfaces. This work broadens the flexibility to generate skyrmions by engineering skyrmion-based devices with nominally symmetric multilayer without the requirement of very large DMI.
High resolution diagnostic tools for superconducting radio frequency cavities
Authors: Parajuli I. , Ciovati G. , Delayen J. R.
Published: November 2022

Superconducting radio-frequency (SRF) cavities are one of the fundamental building blocks of modern particle accelerators. To achieve the highest quality factors (1010–1011), SRF cavities are operated at liquid helium temperatures. Magnetic flux trapped on the surface of SRF cavities during cool-down below the critical temperature is one of the leading sources of residual RF losses. Instruments capable of detecting the distribution of trapped flux on the cavity surface are in high demand in order to better understand its relation to the cavity material, surface treatments and environmental conditions. We have designed, developed, and commissioned two high-resolution diagnostic tools to measure the distribution of trapped flux at the surface of SRF cavities. One is a magnetic field scanning system, which uses cryogenic Hall probes and anisotropic magnetoresistance sensors that fit the contour of a 1.3 GHz cavity. This setup has a spatial resolution of ∼13μm in the azimuthal direction and ∼1 cm along the cavity contour. The second setup is a stationary, combined magnetic and temperature mapping system, which uses anisotropic magnetoresistance sensors and carbon resistor temperature sensors, covering the surface of a 3 GHz SRF cavity. This system has a spatial resolution of 5 mm close to the iris and 11 mm at the equator. Initial results show a non-uniform distribution of trapped flux on the cavities’ surfaces, dependent on the magnitude of the applied magnetic field during field-cooling below the critical temperature.
A lattice Boltzmann method for two-phase nanofluid under variable non-uniform magnetic fields
Authors: Ren Jiyun , Jin Zunlong , Huang Xiaole , Belošević Srdjan , Milićević Aleksandar , Tomanović Ivan , Deng Lei , Che Defu
Published: November 2022

In this study, a new lattice Boltzmann scheme is developed for the two-phase CuO–H2O nanomagnetic fluid (ferrofluid) under a non-uniform variable magnetic field. It introduces the second-order external force term including both MHD (magnetohydrodynamic) and FHD (ferrohydrodynamic) into the lattice Boltzmann equation. The square cavity and a heat source inside the circular cavity with natural convections of nanofluid are investigated, respectively. The effects of Rayleigh number (Ra), the volume fraction of nanoparticles (φ), Hartmann number (Ha) generated by MHD, and magnetic number (MnF) generated by FHD on the nanofluid flow and heat transfer properties, as well as the total entropy generation (Stot) have been examined. The two-phase lattice Boltzmann model has demonstrated that it is more accurate in predicting the heat transfer of nanofluid than the single-phase model. Consequently, the results calculated by the single-phase and the two-phase methods show the opposite trends. It indicates that nanoparticles could enhance heat transfer with maximum values of 1.78% or deteriorate heat transfer with maximum values of 14.84%. The results of the circular cavity show that Ha could diminish the flow intensity, whereas MnF could enhance it. The average Nusselt number (Nuave) on the heat source decreases with the augments of Ha and MnF but increases with Ra. An optimal volume fraction φ = 1% for heat transfer is obtained except for Ra = 104. Stot achieves the maximum value at Ha = 40 when Ra = 105. It increases with a rise of Ra but reduces with an increment of φ.
Identifying incoherent mixing effects in the coherent two-dimensional photocurrent excitation spectra of semiconductors
Authors: Bargigia Ilaria , Gutiérrez-Meza Elizabeth , Valverde-Chávez David A. , Marques Sarah R. , Srimath Kandada Ajay Ram , Silva Carlos
Published: November 2022

We have previously demonstrated that in the context of two-dimensional (2D) coherent electronic spectroscopy measured by phase modulation and phase-sensitive detection, an incoherent nonlinear response due to pairs of photoexcitations produced via linear excitation pathways contributes to the measured signal as an unexpected background [Grégoire et al., J. Chem. Phys. 147, 114201 (2017)]. Here, we simulate the effect of such incoherent population mixing in the photocurrent signal collected from a GaAs solar cell by acting externally on the transimpedance amplifier circuit used for phase-sensitive detection, and we identify an effective strategy to recognize the presence of incoherent population mixing in 2D data. While we find that incoherent mixing is reflected by the crosstalk between the linear amplitudes at the two time-delay variables in the four-pulse excitation sequence, we do not observe any strict phase correlations between the coherent and incoherent contributions, as expected from modeling of a simple system.
Predictive method for flow condensation heat transfer in plain channels
Authors: Fang Xiande , Li Xiaohuan , Luo Zufen
Published: November 2022

The flow condensation heat transfer (FCHT) in plain channels has a variety of applications in many industrial sectors, and thus it is important to predict FCHT coefficients accurately. This paper compiled a large compound FCHT database containing 5607 data points and 30 fluids and presented a strategy for developing a new correlation of FCHT coefficients. The parameter range of the database is the hydraulic diameter D = 0.493–20 mm, vapor quality x = 0.003–0.992, mass flux G = 24–1533 kg/m2 s, heat flux q = 2.9–422 kW/m2, reduced pressure pr = 0.04–0.95, liquid Prandtl number Prl = 1.7–8.5, liquid Reynolds number Rel = 11.6–5.3 × 104, and gas Reynolds number Reg = 75.1–9.1 × 105. Based on the database and strategy, a new general correlation with substantially better accuracy was developed, which is applicable to plain channels of various sizes and a broad operational parameter range. It predicts the database with a mean absolute deviation (MAD) of 14.1%, while the best existing ΔT-independent correlation predicts the database with an MAD of 20.2%. The applicability of the new and 38 existing correlations to individual fluids was assessed. The new correlation performs best for 8 of the 14 fluids that have more than 50 data points in the entire database, while the most accurate existing one performs best only for 2 of them. The Fang number Fa plays an important role in the new correlation, implying that it relates to the fundamental mechanisms of both boiling and condensation heat transfer.
The guiding effect of artificially injected gas bubble on the underwater pulsed spark discharge and its electrical and acoustic parameters after breakdown
Authors: Guo Xu , Sun Ying , Liu Chen-Lei , Jing Lin , Zhang Yuan-Tao , Wang Xiao-Long , Timoshkin Igor
Published: November 2022

The presence of a low density area is beneficial to the facilitation of the underwater pulsed spark discharge, which can be achieved by artificially injecting gas bubble in between the inter-electrode gap. The generation of intensive acoustic waves by such gas-bubble-guided spark discharges makes them promising underwater acoustic sources in multiple practical applications. This paper is aimed at comprehensive investigation of the guiding effect of the injected bubble on the pre-breakdown process of underwater pulsed spark discharges and potential correlations between their subsequent electrical and acoustic parameters with the purpose of optimizing the acoustic emission. The breakdown probability and the pre-breakdown delay were used to evaluate the general facilitation effect brought by the injected bubble. Experimental and numerical works have been conducted and allow observation on the dynamics of the injected bubble under the influence of the applied voltage. Different guiding modes of the injected bubble for plasma streamers' propagation have been observed regarding its relative position. The characteristics of the electrical properties of gas-bubble-guided spark discharges, including the plasma resistance and the plasma energy density, were analyzed by relating them with the breakdown voltage. The dependency of the acoustic wave amplitude and the acoustic efficiency on these electrical parameters was verified, which provides solid regulation principles for the optimization of the plasma-acoustic system for target practical applications.
Bifurcations to quasiperiodicity of the torsional solutions of convection in rotating fluid spheres: Techniques and results
Authors: Sánchez Umbría J. , Net M.
Published: November 2022

The linear stability of the periodic and axisymmetric solutions of the convection in rotating, internally heated, and self-gravitating fluid spheres is presented. The transition to quasiperiodic flows via Neimark–Sacker bifurcations of different azimuthal wave numbers, m, is studied using matrix-free continuation and Floquet theory. Several pairs of Ekman and Prandtl numbers are considered in the region where the first bifurcation from the conduction state gives rise to the axisymmetric solutions. It is shown that the azimuthal wave numbers m = 1 and m = 2 are preferred and that, for small Ekman and Prandtl numbers, the secondary bifurcations to different m accumulate close to the onset of convection. This study confirms some results previously found just by direct simulations. The methods presented can be applied to systems of parabolic partial differential equations with O(2) or SO(2) symmetry group, when a periodic orbit, invariant under the group, loses stability through a Neimark–Sacker bifurcation.
Current density functional framework for spin–orbit coupling
Authors: Holzer Christof , Franzke Yannick J. , Pausch Ansgar
Published: November 2022

Relativistic two-component density functional calculations are carried out in a non-collinear formalism to describe spin–orbit interactions, where the exchange–correlation functional is constructed as a generalization of the non-relativistic density functional approximation. Contrary to non-relativistic density functional theory (DFT), spin–orbit coupling, however, leads to a non-vanishing paramagnetic current density. Density functionals depending on the kinetic energy density, such as meta-generalized gradient approximations, should therefore be constructed in the framework of current DFT (CDFT). The latter has previously exclusively been used in the regime of strong magnetic fields. Herein, we present a consistent CDFT approach for relativistic DFT, including spin–orbit coupling. Furthermore, we assess the importance of the current density terms for ground-state energies, excitation energies, nuclear magnetic resonance shielding, and spin–spin coupling constants, as well as hyperfine coupling constants, Δg-shifts, and the nuclear quadrupole interaction tensor in electron paramagnetic resonance (EPR) spectroscopy. The most notable changes are found for EPR properties. The impact of the current-dependent terms rises with the number of unpaired electrons, and consequently, the EPR properties are more sensitive toward CDFT. Considerable changes are observed for the strongly constrained and appropriately normed functionals, as well as the B97M family and TASK. The current density terms are less important when exact exchange is incorporated. At the same time, the current-dependent kernel ensures the stability of response calculations in all cases. We, therefore, strongly recommend to use the framework of CDFT for self-consistent spin–orbit calculations.
Self-generation of Möbius solitons and chaotic waveforms in magnonic-optoelectronic oscillators under simultaneous action of optic and magnonic nonlinearities
Authors: Kondrashov Alexandr V. , Ustinov Alexey B.
Published: November 2022

Self-generation of microwave nonlinear waveforms in the magnonic-optoelectronic oscillator (MOEO) was investigated. Nonlinear dynamics of the MOEO was due to both optical and magnonic paths of the oscillator circuit. Four-magnon parametric interactions in the magnonic path and cosine transfer function of the electro-optical modulator caused double nonlinearity of the MOEO. Gain coefficient was used as a control parameter. We found that during a route from regular to chaotic dynamics, the oscillator generates two unusual waveforms: symmetry-breaking soliton-like modes of Möbius type and periodic pulses with chaotic amplitude modulation. Nonlinear waveforms were characterized using a time series analysis. Peculiarities of the signals and their spectra in regular and chaotic regimes of self-generation are discussed. We expect that the multiple nonlinearity of the MOEO may be useful for investigation of various fundamental effects in complex time-delayed systems and for development of novel circuits for neuromorphic computing.