bluuebunny/crossref_metadata_2025 huggingface dataset:
Agonism of GPR120 Prevented High Glucose-Induced Apoptosis of Retinal Endothelial Cells through Inhibiting NLRP3 Inflammasome
Authors: Ding Xiaoju , Xie Haijuan , Shan Wuqiang , Li Ligang
Published: May 2022

Purpose GPR120 has been reported to ameliorate inflammation in diabetes and diabetic complications. In this study, GW9508, the GPR120 agonist, was utilized in human retinal
microvascular endothelial cells (HRMECs) exposed to high glucose (HG) to investigate the involvement of GPR120 in cellular viability and apoptosis as well as the association with the NLRP3
inflammasome.

Methods The expression of GPR120 in HRMECs cultured under HG was firstly detected by Western blotting. HRMECs were then assigned to the normal control, GW9508, HG, and HG + GW9508
groups. The expression of the NLRP3 inflammasome consists of NLRP3, ASC, and caspase-1 and was detected by Western blotting and the downstream IL-1β and IL-18 by ELISA. The cellular
viability and apoptosis of HRMECs were detected by CCK-8 and flow cytometry, respectively. The expressions of apoptosis-related proteins Bax and Bcl-2 were detected by Western blotting.
Finally, nonspecific siRNA (NS) or GPR120 siRNA (siGPR120) was transfected to the cells, followed by stimulation with or without GW9508 or HG, and the expression of NLRP3, ASC, and caspase-1
were detected by Western blotting in these groups.

Results GPR120 is expressed in HRMECs, and HG can reduce its expression in a time-dependent manner. GW9508 can attenuate inflammation by reducing the expression of NLRP3, ASC,
caspase-1, IL-1β, and IL-18 under HG. GW9508 rescues the viability of HRMCs and reduces cell apoptosis by preventing an increase in Bax expression and the reduction in Bcl-2
expression. Additionally, knockdown of GPR120 by siRNA weakened the effects of GW9508 on NLRP3 inflammasome expression.

Conclusions Activation of GPR120 protects retinal vascular endothelial cells from HG through inhibiting NLRP3 inflammasome. Thus, GPR120 might be a potential therapeutic target to
reduce retinal endothelial damage in diabetic retinopathy.
Exploring the grammar of othering and antagonism as enacted in terrorist discourse: verbal aggression in service of radicalisation
Authors: Etaywe Awni
Published: May 2022

The social, discursive practice of othering in violent extremist discourse serves to present outgroups as distant yet real threats to the ideological and physical territories of an ingroup which a terrorist claims to represent. However, the role of grammatical choices (namely, non/transactive construction, voice, and mood) in enacting the othering act within the context of radicalisation to terrorism remains to be empirically verified. This paper explores the patterning and pragmatic functions—namely in framing situations, coercing into violence, and legitimising hostile actions against Others—of the syntactic structure of the othering utterances. The othering utterances, as realized in a set of eight public statements produced by former al-Qaeda leader, Osama bin Laden, were sorted manually and analysed qualitatively to help understand and showcase how grammar was strategically leveraged in the process of radicalisation. Results show that the act of othering in the dataset operates within the victimization and injustice frameworks to morally sanction antagonism and aggression via: (i) overt othering, where transactive construction, only declarative mood and active voice are used, and (ii) covert othering, in which nontransactive construction, any mood type, and passive voice are utilized. Overt othering foregrounds, through assertions and statements of presumed facts, the negative agentive role of Others and the diagnostic framing of the causal relationships between Others and negative experiences. Covert othering backgrounds this agentive role to place prominence on immoral actions and to serve in the motivational function of framing. The grammatical patterns provide evidence of the strategic character of OBL’s verbal aggression and how different mood types tend to construct the directive, illocutionary point of the utterances and to enact prognostic framing. The analytical strategy aids in threat assessment and preventing radicalisation by sensitizing assessors to, first, the kind of semiotic clues to engagement in the social and discursive process of radicalisation where utterances count as calls for action and activators of a reality of deontology, and, second, to the social functioning of terrorist texts in: (i) promoting putative readers’ awareness of particular outgroups, and (ii) ideological positioning and encouraging and legitimating violence that is liberty, loyalty and care metavalues-based.
Design of thermal lens phononic nanostructure to generate tunable hotspots using quasi-ballistic phonon transport
Authors: Li Jincui , Weng Linxi , Ramiere Aymeric
Published: May 2022

The direction of the quasi-ballistic thermal flow propagation can be guided using the direct passages between the holes in silicon phononic nanostructures. By designing a radial array of holes where the direct passages converge at the same focal point, we obtain a quasi-ballistic thermal lens nanostructure that creates a hotspot with an ellipse shape away from the holes. We conduct a systematic study of the intensity and size of the hotspot by varying the geometrical features of the thermal lens nanostructure such as the neck size, the number of guiding rows, the diameter of the first row of holes, and the number of direct passages. Our Monte Carlo simulations show a complex interplay between the geometry of the thermal lens nanostructure and hotspot properties through a competition between the guiding effect and the thermal resistance. These results provide guidelines for designing thermal lens nanostructures capable of generating on-demand hotspot properties and shed new light on the possibility of manipulating the quasi-ballistic thermal flow.
Femtosecond x-ray diffraction study of multi-THz coherent phonons in SrTiO3
Authors: Shayduk Roman , Hallmann Jörg , Rodriguez-Fernandez Angel , Scholz Markus , Lu Wei , Bösenberg Ulrike , Möller Johannes , Zozulya Alexey , Jiang Man , Wegner Ulrike , Secareanu Radu-Costin , Palmer Guido , Emons Moritz , Lederer Max , Volkov Sergey , Lindfors-Vrejoiu Ionela , Schick Daniel , Herzog Marc , Bargheer Matias , Madsen Anders
Published: May 2022

We report generation of ultra-broadband longitudinal acoustic coherent phonon wavepackets in SrTiO3 (STO) with frequency components extending throughout the first Brillouin zone. The wavepackets are efficiently generated in STO using femtosecond infrared laser excitation of an atomically flat 1.6 nm-thick epitaxial SrRuO3 film. We use femtosecond x-ray diffraction at the European X-Ray Free Electron Laser Facility to study the dispersion and damping of phonon wavepackets. The experimentally determined damping constants for multi-THz frequency phonons compare favorably to the extrapolation of a simple ultrasound damping model over several orders of magnitude.
Estimation of stagnation performance metrics in magnetized liner inertial fusion experiments using Bayesian data assimilation
Authors: Knapp P. F. , Glinsky M. E. , Schaeuble M. A. , Jennings C. A. , Evans M. , Gunning J. , Awe T. J. , Chandler G. A. , Geissel M. , Gomez M. R. , Hahn K. D. , Hansen S. B. , Harding E. C. , Harvey-Thompson A. J. , Humane S. , Klein B. T. , Mangan M. , Nagayama T. , Porwitzky A. J. , Ruiz D. E. , Schmit P. F. , Slutz S. A. , Smith I. C. , Weis M. R. , Yager-Elorriaga D. A. , Ampleford D. J. , Beckwith K. , Mattsson T. R. , Peterson K. J. , Sinars D. B.
Published: May 2022

We present a new analysis methodology that allows for the self-consistent integration of multiple diagnostics including nuclear measurements, x-ray imaging, and x-ray power detectors to determine the primary stagnation parameters, such as temperature, pressure, stagnation volume, and mix fraction in magnetized liner inertial fusion (MagLIF) experiments. The analysis uses a simplified model of the stagnation plasma in conjunction with a Bayesian inference framework to determine the most probable configuration that describes the experimental observations while simultaneously revealing the principal uncertainties in the analysis. We validate the approach by using a range of tests including analytic and three-dimensional MHD models. An ensemble of MagLIF experiments is analyzed, and the generalized Lawson criterion χ is estimated for all experiments.
Machine learning derived dynamic operating reserve requirements in high-renewable power systems
Authors: Sun Yuchi , Nelson James H. , Stevens John C. , Au Adrian H. , Venugopal Vignesh , Gulian Charles , Kasina Saamrat , O'Neill Patrick , Yuan Mengyao , Olson Arne
Published: May 2022

Accurately forecasting wind and solar power output poses challenges for deeply decarbonized electricity systems. Grid operators must commit resources to provide reserves to ensure reliable operations in the face of forecast errors, a process which can increase fuel consumption and emissions. We apply neural network-based machine learning to expand the usefulness of median point forecast data by creating probabilistic distributions of short-term uncertainty in demand, wind, and solar forecasts that adapt to prevailing grid conditions. Machine learning derived estimates of forecast errors compare favorably to estimates based on incumbent methods. Reserves derived from machine learning are usually smaller than values derived using incumbent methods, which enables fuel savings during most hours. Machine learning reserves are generally larger than incumbent reserves during times of higher forecast error, potentially improving system reliability. Performance is tested using multistage production simulation modeling of the California Independent System Operator system. Machine learning reserves provide production cost and greenhouse gas (GHG) emission reductions of approximately 0.3% relative to historical 2019 requirements. Savings in the 2030 timeframe are highly dependent on battery storage capacity. At lower levels of battery capacity, savings of 0.4% from machine learning reserves are shown. Significant quantities of battery storage are expected to be added to meet California's resource adequacy needs and GHG reduction targets. The addition of these batteries saturates reserve needs and results in minimal within-hour balancing costs in 2030.
Electro-rotation of spheroids in fluids under linear-polarized AC electric field: A dynamic model
Authors: Zhang Yichi , Gu Yu , Zou Yousheng
Published: May 2022

Under a linear-polarized AC electric field, a spheroid suspended in fluids typically aligns one of its axes with the field. The time-averaged torque model is widely used to predict the orientation of the spheroid with respect to the field. Different from the AC case, the dynamical behaviors including stable orientation, stable spinning, and the limit cycle of spheroids under the DC electric field are much richer. An inconsistency exists between the two cases, and a criterion for the validity of the time-average torque model is also missing. In this article, the dynamic model for the DC electric field was adapted to its AC counterpart and the full dynamics of spheroids under the AC field were studied. We bridged the DC and AC dynamics of spheroidal particles and widened the frequency range for applying the time-averaged torque model. It was found that the phase diagram at the DC limit is a very instructive guiding map for predicting the dynamical behavior at the AC field and ωτη ∼ 1 (ω: angular frequency of the electric field, τη: characteristic time of particle rotation) appears to be a universal criterion for the time-averaged model to be effective. The flipping of particle orientation was explained with bifurcations of the periodic solutions and the irregular dynamics at low frequencies were uncovered with the Poincaré map and the power spectrum analysis. Our study sheds light on even richer dynamical behaviors of the particles under the AC electric field and may help realize other unconventional dynamical behaviors of particles in the future.
Impulsive feedback control of birhythmicity: Theory and experiment
Authors: Biswas Debabrata , Banerjee Tanmoy , Kurths Jürgen
Published: May 2022

We study the dynamic control of birhythmicity under an impulsive feedback control scheme where the feedback is made ON for a certain rather small period of time and for the rest of the time, it is kept OFF. We show that, depending on the height and width of the feedback pulse, the system can be brought to any of the desired limit cycles of the original birhythmic oscillation. We derive a rigorous analytical condition of controlling birhythmicity using the harmonic decomposition and energy balance methods. The efficacy of the control scheme is investigated through numerical analysis in the parameter space. We demonstrate the robustness of the control scheme in a birhythmic electronic circuit where the presence of noise and parameter fluctuations are inevitable. Finally, we demonstrate the applicability of the control scheme in controlling birhythmicity in diverse engineering and biochemical systems and processes, such as an energy harvesting system, a glycolysis process, and a p53-mdm2 network.
Improvement of forming-free threshold switching reliability of CeO2-based selector device by controlling volatile filament formation behaviors
Authors: Sahu Dwipak Prasad , Park Kitae , Han Jimin , Yoon Tae-Sik
Published: May 2022

Diffusive memristor-based threshold switching devices are promising candidates for selectors in the crossbar memory architecture. However, the reliability and uniformity of the devices are primary concerns due to uncontrolled diffusion of metal ions in the solid electrolyte of diffusive memristors. In this study, CeO2-based selectors with Ag electrodes were demonstrated to have forming-free threshold switching characteristics. In particular, by inserting an amorphous SiO2 layer in a CeO2-based selector device, we have effectively controlled volatile filament formation that is essential for uniform and reliable switching operations. The inserted SiO2 layer acts as a barrier that could retard the migration of Ag ions and prevents the formation of strong filaments in the solid electrolyte. This enables the bilayer device to have improved uniformity and cyclic endurance. The proposed selector device, Ag/CeO2/SiO2/Pt, showed excellent DC I–V switching cycles (103), high selectivity of 104, good endurance (>104), and narrow distribution of switching voltages. These results would be helpful to implement CeO2-based threshold switching devices as selectors for high-density storage crossbar memory architectures.
Spin-polarized transport properties of the FeCl2/WSe2/FeCl2 van der Waals heterostructure
Authors: Zhu L. , Qu X. X. , Cheng H. Y. , Yao K. L.
Published: May 2022

The discovery of the giant magnetoresistance effect has led to the rapid development of spintronics. Although the half-metals can provide a 100% spin polarization rate and significantly improved giant magnetoresistance, the materials with low Curie temperatures present challenges for their use at room temperature. In an attempt to identify the half-metallic material with high Curie temperatures for spintronics, this study investigates a van der Waals heterostructure with vertically integrated FeCl2/WSe2/FeCl2. The spin-polarized transport properties of the device based on the heterostructure studied by the density function theory combined with nonequilibrium Green's function reveal comprehensive spintronics functions, including giant magnetoresistance, spin filtering, and negative differential resistance effect. The mechanism of the negative differential resistance effect has further been elucidated by the band alignment of the heterostructure under different biases within the bias window.
Effect of compressibility on the small-scale structures in hypersonic turbulent boundary layer
Authors: Xu Dehao , Wang Jianchun , Yu Changping , Li Xinliang , Chen Shiyi
Published: May 2022

The effects of the wall temperature and local compressibility on the small-scale structures, local flow topology, and enstrophy production in the hypersonic turbulent boundary layer are numerically investigated. The colder wall temperature significantly enhances the unstable topologies and non-focal topologies near the wall, mainly due to stronger compressibility and more sheet-like structures. The eigenvalue decomposition of the strain rate tensor is introduced to investigate the mechanism of the enstrophy production and small-scale structures. It is shown that in the near wall region, the enstrophy production is mainly governed by the intermediate eigenvalue of strain-rate tensor through flow topologies unstable node/saddle/saddle (UN/S/S), stable focus/stretching (SFS), unstable focus/stretching, and unstable node/unstable node/unstable node, while the enstrophy destruction is primarily contributed by the intermediate eigenvalue through flow topologies stable node/saddle/saddle, stable focus/compressing (SFC), and stable node/stable node/stable node. Moreover, in the far wall region, the third eigenvalue in flow topology SFS and the intermediate eigenvalue in UN/S/S make major contributions to the enstrophy production, while the first eigenvalue in flow topologies unstable focus/compressing and SFC, and the intermediate eigenvalue in SFC mainly lead to the enstrophy destruction.
A unified approach for calculating free energies of liquid and defective crystals based on thermodynamic integration
Authors: Luo Jinping , Zhou Chenyang , Li Qihang , Liu Lijun
Published: May 2022

Free energy calculation is fundamentally important in the research of physics, chemistry, and materials. Thermodynamic integration is the most common way to estimate free energies. In the research, we proposed a unified approach using atomic simulations to calculate the free energies of liquid and defective crystals. The new approach is based on thermodynamic integration using two alchemical pathways. Softcore potentials are developed for three-body interatomic potentials to realize the alchemical pathways. Employing the new approach, the free energy of the liquid can be calculated without requiring another reference system. The free energy of the defective crystal can be calculated directly at high temperatures. It avoids the singularity at the integration endpoint caused by the defect diffusion, which is a serious problem in the widely used Einstein crystal method. In addition, the new approach can capture the whole free energy of the defective crystal including the contribution of anharmonic and configurational entropy, which are particularly important at high temperatures. The new method is simple yet effective and can be extended to different materials and more complex liquid and defective crystal systems.
An off-the-grid approach to multi-compartment magnetic resonance fingerprinting
Authors: Golbabaee Mohammad , Poon Clarice
Published: May 2022

We propose a novel numerical approach to separate multiple tissue compartments in image voxels and to estimate quantitatively their nuclear magnetic resonance (NMR) properties and mixture fractions, given magnetic resonance fingerprinting (MRF) measurements. The number of tissues, their types or quantitative properties are not a-priori known, but the image is assumed to be composed of sparse compartments with linearly mixed Bloch magnetisation responses within voxels. Fine-grid discretisation of the multi-dimensional NMR properties creates large and highly coherent MRF dictionaries that can challenge scalability and precision of the numerical methods for (discrete) sparse approximation. To overcome these issues, we propose an off-the-grid approach equipped with an extended notion of the sparse group Lasso regularisation for sparse approximation using continuous (non-discretised) Bloch response models. Furthermore, the nonlinear and non-analytical Bloch responses are approximated by a neural network, enabling efficient back-propagation of the gradients through the proposed algorithm. Through numerical experiments on simulated and in vivo healthy brain MRF data, we demonstrate the effectiveness of the proposed scheme compared to baseline multi-compartment MRF methods.
Simultaneous determination of different class of parameters for a diffusion equation from a single measurement
Authors: Kian Yavar
Published: May 2022

This article is devoted to the simultaneous resolution of several inverse problems, among the most important formulation of inverse problems for partial differential equations, stated for some class of diffusion equations from a single boundary measurement. Namely, we consider the simultaneous unique determination of several class of coefficients, some internal sources (a source term and an initial condition) and the fractional order in a diffusion equation from a single boundary measurement. Our problem can be formulated as the simultaneous determination of information about a diffusion process (velocity field, density of the medium) and of the source of diffusion. We consider this problems in the context of a classical diffusion process described by a convection–diffusion equation as well as an anomalous diffusion phenomena described by a time fractional diffusion equation.
Varactor-graphene-based multi-reconfigurable triplet filter with independent tuning of frequency and amplitude
Authors: Chen Jianzhong , Hou Rui , Zhao Yu-Tong , Li Liang , Su Tao
Published: May 2022

In this paper, a multi-reconfigurable filter which consists of three identical varactor-graphene-loaded coaxial substrate integrated waveguide (SIW) resonators is presented. The center frequency and transmission amplitude of the proposed filter is independently reconfigurable by means of electrically controlling the values of the varactor capacitance and the graphene resistance, respectively. Tuners and their bias circuits are mounted on the surfaces of the SIW resonator to adjust the tuning of resonant frequency and unloaded quality factor, which enable to realize the frequency and amplitude of the presented multi-reconfigurable filter. In addition, the proposed filter applies a cascaded triplet topology to generate a transmission zero at the upper side in order to enhance skirt selectivity and out-of-band rejection. The circular shape of the resonator provides great flexibility and produces an additional compactness of the filter. The proposed multi-reconfigurable coaxial SIW filter is designed and fabricated, with high-Q varactors and graphene thin sheets as frequency and amplitude tuning elements, respectively, exhibiting the following reconfigurable characteristics: (a) a wide tuning range of 0.58–1.01 GHz with a constant 1 dB fractional bandwidth of 2 ± 0.2%. (b) A continuous tuning range of amplitude at any center frequency in the achievable frequency band. For instance, the proposed filter can be tuned with an amplitude range of 3.02–19.8 dB by varying the value of the graphene sheet resistance at 1.01 GHz. (c) Free combination of the arbitrary center frequency and attenuation level. The proposed filter with tunable filtering and attenuating responses has widely potential in reconfigurable wireless communication systems and radar systems due to its high integration and versatility.
Photoinduced charge separation at Zn-Pd/TiO2 hybrids interface for enhanced electrochemical and photocatalytic activity
Authors: Bamola P , Rawat S , Pathak D K , Sharma M , Dwivedi C , Farsinezhad S , Kumar R , Sharma H
Published: May 2022

One dimensional nanostructures based hybrids have proven to be potent for photocatalytic applications. The hybrids having modified interface play a vigorous role in enrichment of photocatalytic activity by electronic interaction. Electronic interaction at interface occurs by the formation of electronic barriers (Ohmic/Schottky) that affects the transport of charge carriers and hence photocatalytic activity. The present work reports the switching of role play between Ohmic and Schottky barriers using different hybrids in order to have enhancement in photocatalytic activity. In order to form hybrids, metal nanoparticles (Pd and Zn) and bimetallic nanoparticles (ZnPd) are chosen to study the modification of interface by XPS and UPS. The analysis revealed that Pd and ZnPd crafted TiO2 nanorods (TiO2 NR) shows the formation of Schottky barrier with upward band bending at interface. Similarly, Zn crafted TiO2 NR shows the Ohmic barrier with downward band bending at interface. The band bending in hybrids is accredited to interfacial electronic interaction and charge separation at interface. The modified hybrids are studied for electrochemical analysis using cyclic voltammetry. It is analyzed that higher electrical conductivity is present in ZnPd/TiO2 NR, facilitates the transport of charge carriers. The improved charge separation at interface of ZnPd/TiO2 NR leads to enhanced photocatalytic activity in comparison to Pd/TiO2 NR and Zn/TiO2 NR.
Nanohybrids that consisit of p-type, nitrogen-doped ZnO and graphene nanostructures: synthesis, photophysical properties, and biosensing application
Authors: Chen Wei , Zheng Hui , Zheng Peng , Wu Zhangting , Wu Feimei , Liu Yan , Huo Dexuan , Zheng Liang , Zhang Yang
Published: May 2022

ZnO, a promising material for optoelectronic applications, has attracted considerable attention due to its wide and direct band gap and large exciton binding energy. To understand the applications of this material, fabrication of high quality p-type ZnO is a key step. However, a reliable p-type doping of this material remains a major challenge. In this study, we report p-type nitrogen-doped ZnO nanoparticle, grown in a nitrogen doped graphene layer matrix by a plasma heating process using a natural protein and zinc nitrate as the precursors. The structural characterizations are developed by several microscopic techniques including the field emission electron microscopy, high resolution transmission electron microscopy, x-ray photoelectron spectroscopy, and micro-Raman analysis. In addition, the ultraviolet (UV)–visible absorption characteristics and photoluminescence properties of the samples are studied. Its p-type conduction behaviour is confirmed by the Hall effect measurement, which was ascribed to the high nitrogen dopant concentration in the Zn-poor ZnO, and the related mechanism for the p-type behaviour is also discussed. Moreover, the results of the glucose detection based on the strong green luminescence of glucose indicate that the nitrogen-doped ZnO nanodots/nitrogen-doped graphene layer nanohybrid is also a competitive candidate in the biosensing field.
Impurity temperatures measured via line shape analysis in the island scrape-off-layer of Wendelstein 7-X
Authors: Gradic D , Krychowiak M , König R , Henke F , Otte M , Perseo V , Pedersen T Sunn
Published: May 2022

Impurity temperatures have been determined by a spectroscopic line shape analysis for several species in the divertor scrape-off-layer of the stellarator Wendelstein 7-X (W7-X). Examples include spectral lines from intrinsic elements (C II and C III, He I) as well as from seeded impurities (Ar II, N II) through the divertor gas inlet system. Both Doppler broadening and Zeeman splitting are found to contribute significantly to the impurity line shapes. Zeeman splitting arises due to the confining magnetic field in W7-X and complicates the line shape appearance. By attributing Doppler widths to each of the various Zeeman components, however, we demonstrate that reliable ion temperature values can be derived provided that the presence of the magnetic field is properly accounted for. The spectrally highly resolved lines are analyzed by means of a multi-parameter, least-squares fit routine, which accounts for Doppler broadening, Zeeman splitting, as well as the instrumental broadening of the spectrometer used to measure the spectral line shapes. By spectral fitting of the Zeeman features, it is also found that the line shape analysis can yield values for the local magnetic field, which can be used to localize the impurity radiation approximately provided that the line emission is dominant in a small area intersected by the lines of sight of the spectrometer.
Multiscale structures in three species magnetoplasmas with two positive ions
Authors: Ullah Shafa , Shazad Usman , Iqbal M
Published: May 2022

The self-organization in a multi-ion plasma composed of electrons and two species of positively charged ions is investigated. It is shown that when canonical vorticities and velocities of all the plasma fluids are aligned, the magnetic field self-organizes to Quadruple Beltrami state (superposition of four Beltrami fields). The self-organized magnetic and velocity fields strongly depend on the relative strengths of the generalized vorticities, flows, inertia and densities of the plasma species. Thus, it is possible to generate a wide variety of multiscale magnetic field and flow structures. It is also shown that relaxed magnetic fields and velocities can vary on vastly different length scales simultaneously and are coupled together through singular perturbation generated by Hall effect. In this multi Beltrami self-organized states, then, the dynamo mechanism emerges naturally. The scale separation also suggests the heating of the plasma through a dissipative process. The work could be useful to study the dynamics and morphology of the multiscale magnetic field configurations in laboratory and astrophysical plasmas.
Tightly focused properties of a partially coherent radially polarized power-exponent-phase vortex beam
Authors: Chen Kang , Ma Zhi-Yuan , Hu You-You
Published: May 2022

A partially coherent beam called a radially polarized multi-Gaussian Schell-model power-exponent-phase vortex beam is introduced. Both the analytical formula of the beam propagating through the high-numerical-aperture objective lens based on the vectorial diffraction theory, and the cross-spectral density matrix of the beam in the focal region are derived. Then, the tight focusing characteristics of the partially coherent radially polarized power-exponent-phase vortex beam are studied numerically, and the intensity distribution, degree of polarization and coherence of the beams in the focusing region with different topological charge, power order, beam index and coherence width are analyzed in detail. The results show that the contour of the spot becomes clearer and smoother with the increase in the beam index, and the focal fields of different structures that include the flattened beam can be obtained by changing the coherence width. In addition, by changing the topological charge and power order, the intensity can gather to a point along the ring. These unique properties will have potential applications in particle capture and manipulation, especially in the manipulation of irregular particles.
Linear analysis of plasma pressure-driven mode in reversed shear cylindrical tokamak plasmas
Authors: Zhang Ding-Zong , Feng Xu-Ming , Ma Jun , Guo Wen-Feng , Huang Yan-Qing , Liu Hong-Bo
Published: May 2022

The linear behavior of the dominant unstable mode (m = 2, n = 1) and its high order harmonics (m = 2n, n ≥ 2) are numerically investigated in a reversed magnetic shear cylindrical plasma with two q = 2 rational surfaces on the basis of the non-reduced magnetohydrodynamics (MHD) equations. The results show that with low beta (beta is defined as the ratio of plasma pressure to magnetic field pressure), the dominant mode is a classical double tearing mode (DTM). However, when the beta is sufficiently large, the mode is driven mainly by plasma pressure. In such a case, both the linear growth rate and mode structures are strongly affected by pressure, while almost independent of the resistivity. This means that the dominant mode undergoes a transition from DTM to pressure-driven mode with the increase of pressure, which is consistent with the experimental result in ASDEX Upgrade. The simulations also show that the distance between two rational surfaces has an important influence on the pressure needed in mode transition. The larger the distance between two rational surfaces, the larger the pressure for driving the mode transition is. Motivated by the phenomena that the high-m modes may dominate over low-m modes at small inter-resonance distance, the high-m modes with different pressures and q profiles are studied too.
Atomic-scale insights of indium segregation and its suppression by GaAs insertion layer in InGaAs/AlGaAs multiple quantum wells
Authors: Ma Shu-Fang , Li Lei , Kong Qing-Bo , Xu Yang , Liu Qing-Ming , Zhang Shuai , Zhang Xi-Shu , Han Bin , Qiu Bo-Cang , Xu Bing-She , Hao Xiao-Dong
Published: May 2022

The In segregation and its suppression in InGaAs/AlGaAs quantum well are investigated by using high-resolution x-ray diffraction (XRD) and photoluminescence (PL), combined with the state-of-the-art aberration corrected scanning transmission electron microscopy (Cs-STEM) techniques. To facility our study, we grow two multiple quantum wells (MQWs) samples, which are almost identical except that in sample B a thin GaAs layer is inserted in each of the InGaAs well and AlGaAs barrier layer comparing to pristine InGaAs/AlGaAs MQWs (sample A). Our study indeed shows the direct evidences that In segregation occurs in the InGaAs/AlGaAs interface, and the effect of the GaAs insertion layer on suppressing the segregation of In atoms is also demonstrated on the atomic-scale. Therefore, the atomic-scale insights are provided to understand the segregation behavior of In atoms and to unravel the underlying mechanism of the effect of GaAs insertion layer on the improvement of crystallinity, interface roughness, and further an enhanced optical performance of InGaAs/AlGaAs QWs.
Laser shaping and optical power limiting of pulsed Laguerre-Gaussian laser beams of high-order radial modes in fullerene C60
Authors: Li Jie , Guan Wen-Hui , Yuan Shuo , Zhao Ya-Nan , Sun Yu-Ping , Liu Ji-Cai
Published: May 2022

We study the strong nonlinear optical dynamics of nanosecond pulsed Laguerre–Gaussian laser beams of high-order radial modes with zero orbital angular momentum propagating in the fullerene C60 molecular medium. It is found that the spatiotemporal profile of the incident pulsed Laguerre–Gaussian laser beam is strongly reshaped during its propagation in the C60 molecular medium. The centrosymmetric temporal profile of the incident pulse gradually evolves into a non-centrosymmetric meniscus shape, and the on-axis pulse duration is clearly depressed. Furthermore, the field intensity is distinctly attenuated due to the field-intensity-dependent reverse saturable absorption, and clear optical power limiting behavior is observed for different orders of the input pulsed Laguerre–Gaussian laser beams before the takeover of the saturation effect; the lower the order of the Laguerre–Gaussian beam, the lower the energy transmittance.
Improvement of coercivity thermal stability of sintered 2:17 SmCo permanent magnet by Nd doping
Authors: Wang Chao-Zhong , Liu Lei , Sun Ying-Li , Zhao Jiang-Tao , Zhou Bo , Tu Si-Si , Wang Chun-Guo , Ding Yong , Yan A-Ru
Published: May 2022

The effects of Nd doping on the microstructures and magnetic properties of Sm1–x
Nd
x
(Co0.695Fe0.2Cu0.08Zr0.025)7.2 (x = 0, 0.3, 0.5, 0.7, 1.0) permanent magnets are studied. The scanning electron microscope (SEM) analysis of the solid solution states of the magnets shows that with the increase of Nd content, the distribution of elements becomes inhomogeneous and miscellaneous phase will be generated. Positive temperature coefficient of coercivity (β) appears in each of the samples with x = 0.3, 0.5, and 0.7. The corresponding positive β temperatures are in ranges of about 70 K–170 K, 60 K–260 K, 182 K–490 K for the samples with x = 0.3, 0.5, and 0.7, respectively. Thermomagnetic analysis shows that spin-reorientation-transition (SRT) of the cell boundary phase is responsible for this phenomenon. On the basis of this discovery, the Sm0.7Nd0.3 (Co0.695Fe0.2Cu0.08Zr0.025)7.2 magnet possessing thermal stability with β ≈ –0.002 %/K at the temperature in a range of 150 K–200 K is obtained.
Effects of adjacent bubble on spatiotemporal evolutions of mechanical stresses surrounding bubbles oscillating in tissues
Authors: Zou Qing-Qin , Lei Shuang , Li Zhang-Yong , Qin Dui
Published: May 2022

The cavitation dynamics and mechanical stress in viscoelastic tissues, as the primary mechanisms of some ultrasound therapies, are extremely complex due to the interactions of cavitation bubble with adjacent bubbles and surrounding tissues. Therefore, the cavitation dynamics and resultant mechanical stress of two-interacting bubbles in the viscoelastic tissues are numerically investigated, especially focusing on the effects of the adjacent bubble. The results demonstrate that the mechanical stress is highly dependent on the bubble dynamics. The compressive stress and tensile stress are generated at the stage of bubble expansion and collapse stage, respectively. Furthermore, within the initial parameters examined in this paper, the effects of the adjacent bubble will distinctly suppress the radial expansion of the small bubble and consequently lead its associated stresses to decrease. Owing to the superimposition of two stress fields, the mechanical stresses surrounding the small bubble in the direction of the neighboring bubble are smaller than those in other directions. For two interacting cavitation bubbles, the suppression effects of the nearby bubble on both the cavitation dynamics and the stresses surrounding the small bubble increase as the ultrasound amplitude and the initial radius of the large bubble increase, whereas they decrease with the inter-bubble distance increasing. Moreover, increasing the tissue viscoelasticity will reduce the suppression effects of the nearby bubble, except in instances where the compressive stress and tensile stress first increase and then decrease with the tissue elasticity and viscosity increasing respectively. This study can provide a further understanding of the mechanisms of cavitation-associated mechanical damage to the adjacent tissues or cells.
Measurement-device-independent quantum secret sharing with hyper-encoding
Authors: Ju Xing-Xing , Zhong Wei , Sheng Yu-Bo , Zhou Lan
Published: May 2022

Quantum secret sharing (QSS) is a typical multi-party quantum communication mode, in which the key sender splits a key into several parts and the participants can obtain the key by cooperation. Measurement-device-independent quantum secret sharing (MDI-QSS) is immune to all possible attacks from measurement devices and can greatly enhance QSS’s security in practical applications. However, previous MDI-QSS’s key generation rate is relatively low. Here, we adopt the polarization-spatial-mode hyper-encoding technology in the MDI-QSS, which can increase single photon’s channel capacity. Meanwhile, we use the cross-Kerr nonlinearity to realize the complete hyper-entangled Greenberger–Horne–Zeilinger state analysis. Both above factors can increase MDI-QSS’s key generation rate by about 103. The proposed hyper-encoded MDI-QSS protocol may be useful for future multiparity quantum communication applications.
Nonlinear optical rectification of GaAs/Ga1–x
Al
x
As quantum dots with Hulth-en plus Hellmann confining potential
Authors: Duan Yi-Ming , Li Xue-Chao
Published: May 2022

We investigate the nonlinear optical rectification (NOR) of spherical quantum dots (QDs) under Hulthén plus Hellmann confining potential with the external tuning elements. Energy and wavefunction are determined by using the Nikiforov–Uvarov method. Expression for the NOR coefficient is derived by the density matrix theory. The results show that the applied external elements and internal parameters of this system have a strong influence on intraband nonlinear optical properties. It is hopeful that this tuning of the nonlinear optical properties of GaAs/Ga1–x
Al
x
As QDs can make a greater contribution to preparation of new functional optical devices.
Fusionable and fissionable waves of (2+1)-dimensional shallow water wave equation
Authors: Wang Jing , Ding Xue-Li , Li Biao
Published: May 2022

We investigate a (2+1)-dimensional shallow water wave equation and describe its nonlinear dynamical behaviors in physics. Based on the N-soliton solutions, the higher-order fissionable and fusionable waves, fissionable or fusionable waves mixed with soliton molecular and breather waves can be obtained by various constraints of special parameters. At the same time, by the long wave limit method, the interaction waves between fissionable or fusionable waves with higher-order lumps are acquired. Combined with the dynamic figures of the waves, the properties of the solution are deeply studied to reveal the physical significance of the waves.
Dynamical spontaneous scalarization in Einstein-Maxwell-scalar theory *
Authors: Xiong Wei , Liu Peng , Niu Chao , Zhang Cheng-Yong , Wang Bin
Published: May 2022

We study the linear instability and nonlinear dynamical evolution of the Reissner-Nordström (RN) black hole in the Einstein-Maxwell-scalar theory in asymptotic flat spacetime. We focus on the coupling function

, which facilitates both scalar-free RN and scalarized black hole solutions. We first present the evolution of system parameters during dynamic scalarization. For parameter regions in which spontaneous scalarization occurs, we observe that the evolution of the scalar field at the horizon is dominated by the fundamental unstable mode from linear analysis at early times. At late times, the nonlinear evolution can be considered to be the perturbation of scalarized black holes.
Characterisation of the performance of p-type Si detectors for hard X-ray spectroscopy
Authors: Cline B.D. , Bullough M. , Richardson K. , Thorpe H. , Veale M.C. , Wilson M.D.
Published: May 2022

High-density compound semiconductors with sufficiently-high photon attenuations, such as CdZnTe, are required for the detection of the high-energy X-rays (>20 keV), typical to applications of the HEXITEC ASIC. However, in low-energy applications (2–20 keV), the lower electron-hole-pair generation energy of Si offers the potential of improved spectroscopic resolution. Si-based pixelated X-ray sensors are typically based on n-type material where holes are the carrier that form the signal measured on the pixels. However, the incorporation of p-type dopants into the material enables these sensors to be operated effectively in electron readout. This is similar to CdZnTe sensors, where electrons are measured by the pixels. Critically, this allows a single electron-sensitive chip to be utilised for low- and high-energy measurements. Presented in this paper are the results of the spectroscopic characterisation of four p-type-Si sensors (two 300 μm and two 500 μm thick), manufactured by Micron Semiconductors Ltd., and flip-chip bonded to the HEXITEC ASIC. At 13.94 keV all tested devices displayed average FWHM of <540 eV and the average ASIC-limited FWHM of 489 ± 75 eV measured for a single 300 μm module represents the highest resolution measured with the HEXITEC ASIC. Results also show very low pixel-to-pixel variations in the measured FWHM demonstrating the excellent spatial uniformity of these devices, and a study into the temporal stability of a single detector over a ∼30 h period demonstrated negligible changes in spectroscopic performance.
Toward healthy and liveable cities: a new framework linking public health to urbanization
Authors: Ye Chao , Schröder Patrick , Yang Dongyang , Chen Mingxing , Cui Can , Zhuang Liang
Published: May 2022

Urbanization and public health are becoming intertwined together with global natural and social changes. As recommended by the Tsinghua-Lancet Commission on Health Cities in China, cities hold the key to a healthy China. However, China is facing enormous health risks and challenges stemming from rapid and unhealthy urbanization patterns, which are still dominated by centralized planning for large-scale spatial extension and industrial production facilities. We propose a new conceptual framework to explain the evolving relationship between urbanization and public health, from a spatiotemporal perspective. Healthy China should be given a strong focus on healthy urbanization, wellbeing, and sustainable development. To achieve this objective, we explore the potentials of the concept and approaches of liveable cities to complement the deficiencies of the current centralized planning approach of urbanization. Furthermore, to make the concept of Healthy China operational for policy and urban planning, we propose a set of indicators that can be applied together with the spatiotemporal framework to assess the health and livability of cities.
Effect of generalized (r, q)-distributed electrons on ion polytropic coefficient in bounded plasmas
Authors: Shabbir Sobia , Khan Majid , Kamran M
Published: May 2022

The generalized (r, q) velocity distribution function (VDF) is used to describe the quasineutral region of the basic bounded plasma as presented by Tonks and Langmuir. In this regard, the electrons are assumed to follow the (r, q) VDF, and the ions are assumed to be produced as a result of electron-impact ionization of cold neutrals. The plasma approximation is used to calculate the corresponding ion VDF, as well as the ion density, temperature and polytropic coefficient, as affected by the nonthermal indices r and q. The obtained results correspond to the Maxwellian counterparts in proper limits. The present work will be useful in fusion devices where non-Maxwellian electrons may exist due to various physical phenomena.
A many-body approach to transport in quantum systems: from the transient regime to the stationary state
Authors: Ridley M , Talarico N W , Karlsson D , Lo Gullo N , Tuovinen R
Published: May 2022

We review one of the most versatile theoretical approaches to the study of time-dependent correlated quantum transport in nano-systems: the non-equilibrium Green’s function (NEGF) formalism. Within this formalism, one can treat, on the same footing, inter-particle interactions, external drives and/or perturbations, and coupling to baths with a (piece-wise) continuum set of degrees of freedom. After a historical overview on the theory of transport in quantum systems, we present a modern introduction of the NEGF approach to quantum transport. We discuss the inclusion of inter-particle interactions using diagrammatic techniques, and the use of the so-called embedding and inbedding techniques which take the bath couplings into account non-perturbatively. In various limits, such as the non-interacting limit and the steady-state limit, we then show how the NEGF formalism elegantly reduces to well-known formulae in quantum transport as special cases. We then discuss non-equilibrium transport in general, for both particle and energy currents. Under the presence of a time-dependent drive—encompassing pump–probe scenarios as well as driven quantum systems—we discuss the transient as well as asymptotic behavior, and also how to use NEGF to infer information on the out-of-equilibrium system. As illustrative examples, we consider model systems general enough to pave the way to realistic systems. These examples encompass one- and two-dimensional electronic systems, systems with electron–phonon couplings, topological superconductors, and optically responsive molecular junctions where electron–photon couplings are relevant.