bluuebunny/crossref_metadata_2025 huggingface dataset:
X-ray observations of Blueberry galaxies
Authors: Adamcová B. , Svoboda J. , Kyritsis E. , Kouroumpatzakis K. , Zezas A. , Boorman P. G. , Borkar A. , Bílek M. , Clavel M. , Petrucci P.-O.
Published: September 2024

Context. Compact star-forming galaxies were dominant galaxy types in the early Universe. Blueberry galaxies (BBs) represent their local analogues, being very compact and having intense star formation.

Aims. Motivated by high X-ray emission recently found in other analogical dwarf galaxies, called Green Peas, we probed the X-ray properties of BBs to determine if their X-ray emission is consistent with the empirical laws for star-forming galaxies.

Methods. We performed the first X-ray observations of a small sample of BBs with the XMM-Newton satellite. Spectral analysis for detected sources and upper limits measured via Bayesian-based analysis for very low-count measurements were used to determine the X-ray properties of our galaxy sample.

Results. Clear detection was obtained for only two sources, with one source exhibiting an enhanced X-ray luminosity to the scaling relations. For the remaining five sources, only an upper limit was constrained, suggesting BBs to be rather underluminous as a whole. Our analysis shows that the large scatter cannot be easily explained by the stochasticity effects. While the bright source is above (and inconsistent with) the expected distribution at almost the 99% confidence level, the upper limits of the two sources are below the expected distribution.

Conclusions. These results indicate that the empirical relations between the star formation rate, metallicity, and X-ray luminosity might not hold for BBs with uniquely high specific star formation rates. One possible explanation could be that the BBs may not be old enough to have a significant X-ray binary population. The high luminosity of the only bright source can then be caused by an additional X-ray source, such as a hidden active galactic nucleus or more extreme ultraluminous X-ray sources.
Euclid Early Release Observations -- Globular clusters in the Fornax galaxy cluster, from dwarf galaxies to the intracluster field
Authors: Saifollahi T. , Voggel K. , Lançon A. , Cantiello Michele , Raj M.A. ,   et al.
Published: September 2024

We present an analysis of observations of a 0.6\,deg$^2$ field in the central region of the Fornax galaxy cluster that were acquired during the performance verification phase. With these data, we investigated the potential of to identify globular clusters (GCs) at 20\,Mpc and validated the search methods using artificial GCs and known GCs within the field from the literature. Our analysis of artificial GCs injected into the data shows that data in the IE band is 80 complete at about $I_ E 26.0$\,mag V -5.0$\,mag), and it resolves GCs as small as h = 2.5$\,pc. In the IE band, we detected more than 95 of the known GCs from previous spectroscopic surveys and GC candidates of the ACS Fornax Cluster Survey, of which more than 80 are resolved. We identify more than 5000 new GC candidates within the field of view down to $I_ E = 25.0$\,mag, about 1.5\,mag fainter than the typical GC luminosity function turn-over magnitude, and we investigated their spatial distribution within the intracluster field. We then focused on the GC candidates around dwarf galaxies and investigated their numbers, stacked luminosity distribution, and stacked radial distribution. While the overall GC properties are consistent with those in the literature, we found an interesting over-representation of relatively bright candidates within a small number of relatively GC-rich dwarf galaxies. Our work confirms the capabilities of data in detecting GCs and separating them from foreground and background contaminants at a distance of 20\,Mpc, particularly for low GC-count systems such as dwarf galaxies.
Knobs and dials of retrieving JWST transmission spectra
Authors: Schleich S. , Boro Saikia S. , Changeat Q. , Güdel M. , Voigt A. , Waldmann I.
Published: September 2024

Context. When retrieving exoplanet atmospheric characteristics from spectroscopic observations, parameter estimation results strongly depend on the chosen forward model. In the era of the James Webb Space Telescope (JWST) and other next-generation facilities, the increased signal-to-noise ratio (S/N), wavelength coverage, and spectral resolution of observations warrant closer investigations into factors that could inadvertently bias the results of these retrievals.

Aims. We aim to investigate the impact of utilising multi-point pressure–temperature (p–T) profiles of varying complexity on the retrieval of synthetically generated hot-Jupiter transmission spectra modelled after state-of-the-art observations of the hot Jupiter WASP-39 b with JWST.

Methods. We performed homogenised atmospheric retrievals with the TauREx retrieval framework on a sample of synthetically generated transmission spectra, accounting for varying cases of underlying p–T profiles, cloud-top pressures, and expected noise levels. These retrievals are performed using a fixed-pressure multi-point p–T prescription with increasing complexity, ranging from isothermal to an eleven-point profile. We evaluated the performance of the retrievals based on the Bayesian model evidence, and the accuracy of the retrievals was compared to the known input parameters.

Results. We find that performing atmospheric retrievals using an isothermal prescription for the pressure–temperature profile consistently results in wrongly retrieved atmospheric parameters when compared to the known input parameters. For an underlying p–T profile with a fully positive lapse rate, we find that a two-point profile is sufficient to retrieve the known atmospheric parameters, while under the presence of an atmospheric temperature inversion, we find that a more complex profile is necessary.

Conclusions. Our investigation shows that, for a data quality scenario mirroring state-of-the-art observations of a hot Jupiter with JWST, an isothermal p–T prescription is insufficient to correctly retrieve the known atmospheric parameters. We find a model complexity preference dependent on the underlying pressure–temperature structure, but we argue that a p–T prescription on the complexity level of a four-point profile should be preferred. This represents the overlap between the lowest number of free parameters and the highest model preference in the cases investigated in this work.
Discovery of two cyano derivatives of acenaphthylene (C12H8) in TMC-1 with the QUIJOTE line survey
Authors: Cernicharo J. , Cabezas C. , Fuentetaja R. , Agúndez M. , Tercero B. , Janeiro J. , Juanes M. , Kaiser R. I. , Endo Y. , Steber A. L. , Pérez D. , Pérez C. , Lesarri A. , Marcelino N. , de Vicente P.
Published: September 2024

We report the discovery in TMC-1 of two cyano derivatives of the PAH acenaphthylene (C12H8). We have found two series of lines with the QUIJOTE line survey that we assign to 1-C12H7CN and 5-C12H7CN. For the 1-isomer, we have detected and assigned 173 rotational transitions with J up to 46 and Ka up to 9, corresponding to 107 independent frequencies. For the 5-isomer, the identification is based on 56 individual lines, corresponding to 117 rotational transitions with J up to 40 and Ka up to 8. Identification of the carriers was achieved through a careful analysis of the derived rotational constants, which permit us to focus on molecules larger than naphthalene but smaller than anthracene and phenanthrene. Moreover, the derived rotational constants indicate that the species are planar; this allows us to discard derivatives of fluorene and acenaphthene, which are non-planar species. Quantum chemical calculations and subsequent chemical synthesis of these molecules, as well as the observation of their rotational transitions in the laboratory, unequivocally support our identifications. We also confirm, via a robust line-by-line detection, the previous claimed detection of 1- and 2-cyanonaphthalene, which were obtained through statistical stacking techniques. The column densities of 1- and 5-cyanoacenaphthylene are (9.5 ± 0.9) × 1011 cm−2, while those of 1- and 2-cyanonapthalene are (5.5 ± 0.5) × 1011 cm−2. Hence, it seems that acenaphthylene could be a factor of 1.7 more abundant than naphthalene. These results support a scenario in which PAHs grow in cold dark clouds based on fused five- and six-membered carbon rings.
A regional space weather hazard variation index utilising Swarm FAST data
Authors: Orr Lauren , Beggan Ciarán , Brown William
Published: September 2024

We develop a new method for the determination of a regional hazard indicator using Swarm satellite near-real-time Fast Track (‘FAST’) data based on pre-computed threshold exceedances. The European Space Agency (ESA) aim to deliver the FAST data promptly (currently twice daily) compared to the standard four-day lag with Swarm operational (‘OPER’) data. This provides an opportunity to map localized intense field variation during geomagnetic storms in areas without fixed ground-based magnetometers. To determine the location-dependent threshold above which we consider the magnetic field to be highly active, we compute the 20-s standard deviation of the magnetic field along the track and create baseline thresholds derived from 10 years of Swarm data. Using the standard 1 Hz Level1b LR MAG product, we first remove models of the core, crust and magnetosphere before analysing the ionospheric residuals to determine geomagnetically quiet and active thresholds. We bin the residuals into 20,840 quasi-uniform grid cells globally and compute the typical magnetic field variance expected in each cell. From the binned magnetic variances, we can determine thresholds for exceedance e.g. at the 99th percentile in each grid cell. If the value of the magnetic variation computed from Swarm FAST data, using the same method, exceeds the pre-determined thresholds within the bin, this indicates a highly variable magnetic field in the region, implying a localized increase in space weather hazard risk in regions without ground observatories. We present our Swarm-specific index which we can compare to other geomagnetic indices such as Kp. Our index compares well to Kp and the higher-cadence Hp60 and captures activity levels during both geomagnetic storms and quiet times. Using FAST data, we can quickly quantify the hazard on a per-orbit (or shorter) basis, thus providing as close to real-time geomagnetic activity monitoring as presently feasible. The methodology can also be used by other satellite missions surveying magnetic fields.
Exploring the HPLC Profiling and Antioxidant Potency in Methanolic
Extracts of Curcuma longa L. Rhizomes
Authors: Shukla Babita , Kushwaha Poonam
Published: September 2024

In this exploration of Curcuma longa Linn., commonly known as turmeric,
renowned for its therapeutic history, our study focuses on the bioactive
compound curcumin. We established and validated an HPLC method for precise
curcumin quantification, complemented by an examination of total phenolic and
flavonoid content, as well as antioxidant capabilities in a methanolic extract
from C. longa rhizomes obtained through a methanol-based Soxhlet
extraction. The HPLC analysis utilized a C18 column with a mobile phase of
70:30 V/V Acetonitrile (ACN) to Water (with 1% Glacial Acetic Acid) under an
isocratic elution at 1 mL/min, detection at 420 nm, and a reference standard.
The method exhibited notable accuracy, precision, and reproducibility.
Antioxidant potential, assessed through DPPH, nitric oxide, and hydroxyl radical
scavenging assays, unveiled significant total phenol and total flavonoid
quantities, highlighting C. longa’s potent antioxidant capacity. The
study demonstrated a correlation between antioxidant activities and phenolic and
flavonoid concentrations, reinforcing the robustness of our method. In
conclusion, this method offers an effective means of quantifying curcumin within
C. longa rhizomes and holds promise as a valuable tool for
maintaining quality control in the production of this botanical material.
The Prevalence of Cytogenetic Abnormalities Detected by Interphase FISH Method in Chronic Lymphocytic Leukemia
Authors: Azhdari Shirin , Noori Sadat , Daneshbod Khosrow , Khalafi-Nezhad Abolfazl , Hashemi Seyed Mohammad Ali , Faghih Zahra , Haghighat Shirin , sarvari Jamal
Published: September 2024

Background Chronic lymphocytic leukemia (CLL) is the most prevalent adult leukemia. Identification of genomic aberration provides prognostic/predictive information that is helpful in the precision medicine management of these patients. The aim of this study was to determine prevalence of the most common cytogenetic abnormalities of CLL patients in the southwest region (Shiraz) of Iran and correlate with clinical prognostic parameters to clarify their prognostic value.

Materials and Methods In this cross-sectional study, 100 patients with CLL were recruited from April 2019 to October 2021. Four milliliters of anticoagulated peripheral blood was collected from each participant. The sample was used for complete blood count (CBC) test and fluorescence in situ hybridization (FISH) test. Interphase FISH (I-FISH) was performed for most common cytogenetic abnormalities, including trisomy 12, 13q14 deletion, 11q deletion, and 17p deletion on interphasic cell nuclei.

Results Among 100 patients with CLL, 33 (33%) were females and 67 (67%) were males. The mean age (mean ± standard error [SE]) of the patients was 59.00 ± 1.14 years, with a ranged of 25 to 79 years. Our analysis demonstrated that 86 (86%) patients had at least one chromosomal aberration. The most commonly detected abnormality was 13q deletion (61, 61%), followed by 17q deletion (50 cases, 50%). Trisomy 12 was detected in 14 (14%) cases and 10 cases (10%) had 11q deletion.

Conclusion The higher frequency of 13q14 and 17p anomalies in our study may be attributed to delayed medical consultations, leading to the emergence of secondary abnormalities. More studies are recommended for verifying the results.
Public acceptability of climate-motivated rationing
Authors: Lindgren Oskar , Elwing Erik , Karlsson Mikael , Jagers Sverker C.
Published: September 2024

Recent reports from climate scientists stress the urgency to implement more ambitious and stringent climate policies to stay below the 1.5 °C Paris Agreement target. These policies should simultaneously aim to ensure distributional justice throughout the process. A neglected yet potentially effective policy instrument in this context is rationing. However, the political feasibility of rationing, like any climate policy instrument, hinges to a large extent on the general public being sufficiently motivated to accept it. This study reports the first cross-country analysis of the public acceptability of rationing as a climate policy instrument by surveying 8654 individuals across five countries—Brazil, Germany, India, South Africa, and the US—on five continents. By comparing the public acceptability of rationing fossil fuels and high climate-impact foods with consumption taxes on these goods, the results reveal that the acceptability of fossil fuel rationing is on par with that of taxation, while food taxation is preferred over rationing across the countries. Respondents in low-and middle-income countries and those expressing a greater concern for climate change express the most favourable attitudes to rationing. As political leaders keep struggling to formulate effective and fair climate policies, these findings encourage a serious political and scientific dialogue about rationing as a means to address climate change and other sustainability-related challenges.
Study of photoluminescence from defects in electron-irradiated beta-Ga2O3
Authors: Zhang Yufei , Li Jing , Xiao Zunpeng , Jia Gangyuan , Wang Kaiyue , Qin Zhenxing , Li Junlin
Published: September 2024

Research on the defects of β-Ga2O3 is the first step toward its application in high-end fields. However, there is still controversy over which defect structure is the origin of the 660–850 nm (near-infrared) photoluminescence (PL) band. The low-temperature PL spectrum was employed to study the PL properties of the 660–850 nm band. In addition, the intrinsic defects were artificially introduced into the (100) plane β-Ga2O3 crystal by electron irradiation, resulting in significant enhancement of the 660–850 nm band. Deconvolution fitting analysis combined with lattice relaxation theory indicated that the band was caused by both zero and single or multiple phonon transitions. According to the crystal structure and formation energy simulation, it was considered that the 660–850 nm PL band was related to oxygen vacancies at the three equivalent positions in the lattice.
Charge stabilization in corona electrets made of HDPE film due to the formation of deep electron traps during its orientational stretching
Authors: Pakhotin V. A. , Semenov S. E.
Published: September 2024

Pre-orientation stretching of high-density polyethylene improves the charge stability of electrets produced in corona discharge. Electrets made of oriented polyethylene charged in the corona under uniaxial tensile mechanical stress have even greater stability. The increased stability of electrets is due to the capture of electrons in deep structural traps formed after the rupture of macromolecules during orientation and mechanical stress. By the method of thermally stimulated electron emission, it is shown that the charge of electrets is formed at the expense of electrons. New convenient formulas for calculation of electrical voltages in multilayer insulation with electrets were obtained.
Experimental and theoretical analysis of magnetic-thermal-mechanical coupling of permanent magnet coupling
Authors: Liu Kun , Gao Hanyang , Hu Guoxin , Cui Hongbiao
Published: September 2024

Permanent magnet coupling (PMC) generates a large amount of thermal energy due to the eddy current induced in the metal isolation cylinder, resulting in performance degradation. The magnetic-thermal-mechanical coupling analysis has an important impact on the design and operation of PMC devices. In this paper, the Maxwell equations are solved based on the separated variable method; the 3D eddy current loss and magnetic torque equations are proposed; and the electrical conductivity, the convective heat transfer coefficient, and the magnetic-thermal-mechanical properties of PMC are presented. The 3D analytical coupling model calculates the temperature field and presents an uneven distribution of temperature along the coolant flow direction, and it then obtains a more precise magnetic field and torque under various temperatures. Furthermore, the working conditions such as rotor speed, coolant flow rate, and applied load are taken into consideration in the 3D analytical model. The results show that the eddy current loss is proportional to the square of the speed. With an increase in the load, the eddy current decreases. However, with an increase in the coolant flow, more eddy current loss would be produced, but the generated heat would be taken away by the increased coolant flow, resulting in a decrease in the temperature. The 3D analytical coupling model results are in good agreement with the experimental data, which is helpful to the design and optimization of the PMC system.
Impact of atmospheric turbulence on wind farms sited over complex terrain
Authors: Singh Jagdeep , Alam Jahrul
Published: September 2024

This article investigates the impact of atmospheric turbulence on wind farms in mountainous regions using Scale-Adaptive Large-Eddy Simulation (SALES) combined with the immersed boundary method. An array of 25 Gaussian hills was considered to mimic the mountainous terrain, and three cases were simulated: atmospheric boundary layer flow over complex terrain, 25 full-scale turbines positioned on hilltops, and 125 full-scale turbines positioned across the mountainous landscape. These simulations captured the intrinsic spatial inhomogeneity caused by the complex topographic features of mountainous terrain, challenging the assumption of horizontally homogeneous atmospheric turbulence. This study emphasizes the significance of velocity gradient dynamics and stresses on surface mounted obstacles to evaluate data quality and uncertainty. However, it also considered more detailed comparisons with other methods, validation of topographic impact using experimental work with windbreak and isolated hill, and a comprehensive analysis of the results. The findings include significantly enhanced power production at hilltop turbine locations as compared to homogeneous terrain. Although wind turbines in windward and leeward directions experienced a reduced power output in the near-wake region, these local losses recovered globally by the enhanced vertical energy entrainment from higher altitudes. Additionally, the presence of mountains indicated an increase in the power density by up to five times compared to flat terrain. A wavelet-based autoencoder demonstrated superior performance in separating the harmonic component of time-varying mean and subgrid-scale fluctuations compared to constant and Gaussian weighting kernels. The study suggests wavelet filtering as a promising technique for subgrid-scale modeling, offering improvements not only in wind energy applications but also in other turbulence flow scenarios.
Aluminum relaxation as the source of excess low energy events in low threshold calorimeters
Authors: Romani Roger K.
Published: September 2024

A previously unexplained background called the Low Energy Excess has negatively impacted the reach of a variety of low threshold calorimeters including light dark matter direct detection and coherent elastic neutrino-nucleus scattering experiments. The relaxation of stressed aluminum films as mediated by the motion of dislocations may account for these observations.
Light scattering by V4O7 film across the metal–insulator transition
Authors: Bartenev Alexander , Verbel Camilo , Camino Fernando , Rua Armando , Lysenko Sergiy
Published: September 2024

The experimental study of the angle-resolved hemispherical light scattering by V4O7 film within a broad temperature range across metal–insulator transition reveals complex structural reorganization of the film deposited on the c-cut sapphire crystal. The bidirectional scattering distribution function and the surface autocorrelation function were obtained from scattering data to visualize statistics of the spatially resolved contributions of optical inhomogeneities in normal and lateral directions to the surface. The measurements reveal an anisotropic surface roughness distribution due to the twinned domain structure, with significant anisotropy changes across the phase transition. The V4O7 film deposited on sapphire leads to a polydomain structure, minimizing elastic strain energy with distinct multiscale distributions of surface domains. Near Tc, the material shows the lowest roughness but the highest lateral disorder of the surface.
A comparison of two-phase flow pressure drop components in proton exchange membrane fuel cell flow channels
Authors: Abdollahpour Amir , Marefati Sanaz , Khaled Mahmoud , Mortazavi Mehdi
Published: September 2024

Proton exchange membrane (PEM) fuel cells serve a crucial role in the US decarbonization roadmap. However, water management challenges, such as liquid water accumulation in flow channels, can hinder their long-term performance. Accurately predicting the two-phase flow pressure drop is crucial to identify the extent of water accumulation on fuel cell performance. This study focuses on evaluating the liquid-gas two-phase flow pressure drop components in the flow channels of PEM fuel cells, considering different water transport mechanisms. The three components subject to study were the frictional, accelerational, and gravitational pressure gradients. The models considered in this transport phenomena incorporate electro-osmotic drag and back diffusion. The analysis also considers water evaporation and inlet reactant humidity as factors influencing water transport and pressure drop. The results provide insights into the significance of the different pressure drop components in this two-phase flow system. For the conditions considered in this study the accelerational and gravitational pressure gradients are less than 0.015% and 1.5% of the frictional pressure gradient, respectively. This study addresses a gap in the literature by documenting and validating the negligible effects of accelerational and gravitational pressure drops in two-phase flow within PEM fuel cells. These findings insights contribute to more accurate modeling and optimization of PEM fuel cell performance in practical applications.
High-fidelity lensless imaging with single hologram based on physics-guided frequency-aware network
Authors: Xiong Yibin , Zhou Zeyu , Xu Yufan , Wang Xilong , Yang Xuanbing , Wu Jianhui , Zhou Feng
Published: September 2024

Lensless in-line holography is widely used to obtain depth information on pathological tissues and biological cells to enable noninvasive analysis, due to low cost and large field-of-view. However, existing systems suffer from crosstalk dilemma of twin-image that limit their capability to achieve high-resolution phase imaging with a single measurement, especially in the presence of noise. In this Letter, we propose a physics-guided frequency-aware network (FA-PGNet) for single-shot lens-free holographic reconstruction. The FA-PGNet method uses frequency-level supervision to balance the high- and low-frequency information between images and gradually obtained reliability results by incorporating a physical model. With the co-addition of frequency-aware and physics-guided, it can easily tackle the twin-image and speckle noise, with 5.88 dB improvement on the peak signal-to-noise ratio and 6-fold reduction on the uncertainty of the imaging system. Optical experiments demonstrate that the FA-PGNet allows access to complex features of microscopic cells with high resolution. We believe that the proposed method provides a powerful tool for single-shot cell imaging.
mpsqd: A matrix product state based Python package to simulate closed and open system quantum dynamics
Authors: Guan Weizhong , Bao Peng , Peng Jiawei , Lan Zhenggang , Shi Qiang
Published: September 2024

We introduce a Python package based on matrix product states (MPS) to simulate both the time-dependent Schrödinger equation (TDSE) and the hierarchical equations of motion (HEOM). The wave function in the TDSE or the reduced density operator/auxiliary density operators in the HEOM are represented using MPS. A matrix product operator (MPO) is then constructed to represent the Hamiltonian in the TDSE or the generalized Liouvillian in the HEOM. The fourth-order Runge–Kutta method and the time-dependent variational principle are used to propagate the MPS. Several examples, including the nonadiabatic interconversion dynamics of the pyrazine molecule, excitation energy transfer dynamics in molecular aggregates and photosynthetic light-harvesting complexes, the spin-boson model, a laser driven two-state model, the Holstein model, and charge transport in the Anderson impurity model, are presented to demonstrate the capability of the package.
Insights into the ferroelectric orthorhombic phase formation in doped HfO2 thin films
Authors: Wen Yichen , Wu Maokun , Cui Boyao , Wang Xuepei , Wu Yishan , Li Yu-Chun , Ye Sheng , Ren Pengpeng , Lu Hong-Liang , Wang Runsheng , Ji Zhigang , Huang Ru
Published: September 2024

Despite the extensive research on HfO2-based thin films, the ferroelectric orthorhombic phase formation remains unclear. This work proposes a physical picture throughout the entire annealing process to describe the phase transition. Subsequently, the phase evolution at various doping and annealing temperatures is illustrated based on a kinetic model formalized from the classical nucleation theory. It is found that the formation of the ferroelectric orthorhombic phase depends not only on a modest doping concentration but also on the thermal activation of the t-to-o phase transition provided by a sufficient annealing temperature. In addition, phase transition rates correlated to the monoclinic phase formation are effectively suppressed by doping. The exploration of combined effects of annealing parameters indicates a more decisive role of the annealing temperature rather than the keeping time for induced ferroelectricity, and the doping impact becomes significant when a critical annealing temperature is reached. This work provides an understanding for exploring the kinetic effect on the phase transition in HfO2-based thin films, which helps improve ferroelectricity in doped HfO2 ferroelectric films.
Theoretical investigations on the radiative opacity of Sn plasmas with an open 4d orbital using a detailed-level accounting model
Authors: Yan Guanpeng , Gao Cheng , Hou Yong , Jin Fengtao , Li Yongjun , Zeng Jiaolong , Yuan Jianmin
Published: September 2024

The radiative opacity of Sn plasmas plays a crucial role in the investigation of extreme ultraviolet (EUV) lithography. In this study, a complete atomic database of Sn4+–Sn18+ is established, and the spectrally resolved and mean opacities are investigated using a detailed-level accounting model. The energy levels and oscillator strengths are obtained in the multiconfiguration Dirac–Hartree–Fock framework. Large-scale configuration interaction calculations are performed in which the number of fine structure levels is on the order of 2 × 105 for each ionization stage. The electron correlation effects are considered to obtain accurate transition data in EUV regions. The photoionization cross sections are calculated using the distorted wave method. The spectrally resolved radiative opacities at temperatures of 5–40 eV and densities of 0.0001–1.0 g/cm3 are investigated. The spectral characteristics are demonstrated with variable temperatures and densities. The main contribution to absorption lines in the EUV region arises from Sn10+ and nearby ions, and the optimized temperatures and densities producing Sn10+ are presented. The Planck and Rosseland mean opacities are given at variable temperatures and densities, which is helpful for radiation hydrodynamic simulations of laser–Sn interactions.
THz probing of non-trivial topological states in Co2MnGe Heusler alloy thin films
Authors: Yadav Ekta , Nivedan Anand , Kumar Sunil
Published: September 2024

Co2MnGe (CMG) has been demonstrated recently as a half-metallic ferromagnetic Heusler alloy, which possesses a topologically non-trivial band structure. This behavior is unique to such systems and hence warrants extensive experimental exploration for potential spintronic and chirality sensitive optoelectronic applications. Here, we demonstrate that an epitaxial thin film of CMG acts as a source of terahertz (THz) radiation upon photoexcitation by optical femtosecond laser pulses. Detailed experiments have revealed that a large contribution to THz emission occurs due to nonmagnetic or spin-independent origin; however, a significant contribution in the THz generation is evidenced through an excitation light helicity-dependent circular photogalvanic effect confirming the presence of topologically non-trivial carriers in the epitaxial CMG thin films. Furthermore, we show that not only the topological contribution is easily suppressed but also the overall THz generation efficiency is also affected adversely for the epitaxial films grown at high substrate temperatures.
Optimization of pleated filters
Authors: Fong Daniel , Sanaei Pejman
Published: September 2024

Pleated membrane filters are ubiquitous in many industrial filtration systems due to their high surface-area-to-volume ratio. However, their performance often falls short compared to flat non-pleated membrane filters of the same membrane surface area. This raises the question: What is the optimal initial internal pore structure of the membrane to achieve the most efficient filtration? To address this question, we first present a mathematical model describing the feed flow and particle transport within the complex geometry of a pleated filter based on our previous work [Fong and Sanaei, “Flow and transport in a pleated filter,” Phys. Fluids 34, 097102 (2022)]. We then analyze the governing equations using asymptotic analysis by exploiting the small aspect ratios of the pleated membrane and filter cartridge. In the second part of the paper, we formulate a computationally efficient optimization problem aimed at determining the optimal initial pore shape to improve filtration performance. Depending on the initial average porosity, substantial differences in the computed optimal pore profile are observed. Furthermore, by varying a geometric parameter in our model, we investigate the influence of the pleat packing density on the optimal initial pore shape.
Experimental study of arc plasma energy deposition flow control on supersonic cavity combustor
Authors: Wang Ao , Chen Zhi , Feng Liming , Ding Hao , Huang Zhenxin , Tian Lifeng
Published: September 2024

This investigation conducted an experimental study of flow control in a Mach 2.5 cavity combustor using arc plasma energy deposition (APED), implemented both with and without injection. APED was produced by a pulsed arc discharge plasma actuator at frequencies of 5, 10, 15, and 20 kHz. The objective is to elucidate the influence and underlying mechanisms of APED on the flow dynamics by statistically evaluating time-resolved schlieren images and monitoring pressure fluctuations throughout the control process. The findings indicate that APED significantly modifies the energy distribution across unsteady modes and alters the pressure distribution within the flow field. In scenarios without injection, high-frequency discharge triggers oscillations in the shear layer; the impact of precursor shocks and thermal bubbles diminishes the magnitude and fluctuations of both shear layer-induced and internal shocks. Conversely, in the injection scenario, high-frequency discharge, in conjunction with oscillations of the boundary layer and bow shocks, amplifies the oscillation amplitude and frequency of jet vortex shedding. Additionally, APED intensifies the pulsation and penetration depth of the jet, which is essential for enhancing the mixing efficiency of the incoming flow with fuel. The effectiveness of the control is positively correlated with the actuator's discharge frequency, or its average power, within the confines of this study.
Interface design for the optimal optoelectronic conversion properties of MoS2/WS2/WSe2 van der Waals heterostructures
Authors: Dong Jiansheng , Liu Junjie , Liao Wenhu , Yang Xuexian , He Yan , Ouyang Gang
Published: September 2024

The interfacial nature of few-layer transition metal dichalcogenide (TMD)-based van der Waals heterostructures (vdWHs) plays a vital role in their optoelectronic properties and can greatly influence charge transfer and recombination. Here, we consider a trilayer MoS2/WS2/WSe2 vdWH with ladder band alignment and address the relationship between the interface character and optoelectronic properties in terms of the atomic-bond-relaxation approach, Marcus theory, and the detailed balance principle. We find that a trilayer vdWH with ladder band alignment exhibits ultrafast interface charge transfer, and the interface barrier induced by the middle WS2 layer can significantly suppress interlayer recombination. The power conversion efficiency (PCE) of trilayer MoS2/WS2/WSe2 vdWHs can reach 2.43%. Our findings show that the PCE of MoS2/WS2/WSe2 vdWHs is obviously better than that of bilayer heterostructures, suggesting that the design of ladder band alignment can be an effective way to achieve highly efficient TMD-based photovoltaic devices.
Aerodynamic interference effects of bridge-train-like bluff bodies with small flow attack angle
Authors: Zhu Qingchi , Zhou Lei , Tse Kam Tim , Ning Xizhan , Zhang Hongfu
Published: September 2024

This paper employs numerical simulation to examine the impact of variations in flow angle of attack (α) and low Reynolds number (Re) on the aerodynamic performance of the RC-TLBB (rectangle cylinder and train-like bluff body) system subjected to crosswinds. The RC-TLBB system consists of a train-like bluff body with a 5:1 cross section rectangle cylinder, and the rectangle cylinder cross section is used alone as a without-train group. The research indicates that the presence of the upper TLBB amplifies the influence of Re and α on the lift and drag of the rectangle cylinder. The alteration in α results in similar trends for both CL′ and C¯D of the TLBB and the rectangle cylinder. For Re, the trend is reversed. The rise in both α and Re enhances the correlation between the lift coefficient and drag coefficient. Nonetheless, the correlation between lift and drag coefficients exhibits greater strength for a rectangle cylinder in the system compared to a single rectangle cylinder in the without-train group. The presence of the TLBB spatially forces the separation of the shear layers, and the vortex shedding phenomenon on the upper side of the rectangle cylinder precedes that on the lower side at low Re. The increase in Re changes this phenomenon to the lower side preceding the upper side. This study illustrates the potential flow-induced problems by analyzing the various aerodynamic parameters of the system, which provides a theoretical basis for ensuring the safety and reliability of the system.
New third-order weighted essentially non-oscillatory scheme with novel compact nonlinear weights based on the forward-divided differences
Authors: Musa Omer , Huang Guoping , Yu Zonghan
Published: September 2024

The current paper proposes a new third-order WENO (weighted essentially non-oscillatory) scheme, denoted as WENO-D3, which constructs the numerical flux using the convex combination of a second-degree polynomial of a three-point stencil with two linear polynomials of two substencils. WENO-D3 comes with a compact formulation of the numerical flux, new compact nonlinear weights, a new reference smoothness indicator, and a simple smoothness indicator for the three-point stencil. The forward differences approach is employed to reformulate the expressions of the polynomials and smoothness indicators of the new scheme. The smoothness indicator of the three-point stencil is designed using a linear combination of the two-point substencil smoothness indicators and compact linear weights. The linear weights of WENO-D3 can be freely selected with one condition: their sum equals one. A detailed analysis of the WENO-D3 scheme is provided, and numerous one- and two-dimensional benchmark numerical experiments are studied. Thirty-one combinations of linear weights are studied to verify the sensitivity of WENO-D3 to linear weights selection. Compared to the WENO-MZQ3 scheme, the WENO-D3 scheme significantly reduced the computational complexity and cost while providing flexibility in linear weights selection. The results show that the new scheme reduces up to 91% of the WENO-MZQ3 scheme's computational time and provides stable results for a wide range of linear weights. The results also show that the proposed scheme has recovered the optimal order at critical points and can capture and resolve sharp discontinuities without spurious oscillations.
Self-consistent statistical model for current transport in polycrystalline semiconductors
Authors: Benford Eva L. C. , Amit Iddo
Published: September 2024

Transport in novel materials, specifically those scaled up to wafer sizes, will be dominated by thermionic emission over charged, randomly oriented grain boundaries. However, the challenges presented by random dopant fluctuation in lightly and moderately doped nano-crystalline materials are yet to be addressed. Here, we present a self-consistent model to describe the transport in polycrystalline materials with medium doping levels, where conductivity is governed by thermionic emission over low and wide barriers. We show that random doping fluctuations contribute to a higher material resistivity, which is explained through a non-linear potential drop over the depletion regions on both sides of the boundary. This leads to a decrease in the exponential slope at the onset of conductivity, down to values of ∼exp⁡(−2.4kT)−1, as well as to asymmetry in the current–voltage characteristics. We demonstrate that the model can be scaled up to several grains and their boundaries, by using commercially available circuit simulators, where non-linearity is realized through look-up tables. We find that an increase in resistivity of up to 18% compared to the nominal, uniformly doped material can be explained simply by the introduction of random dopant fluctuations.
An analysis of a 2 × 2 Keyfitz–Kranzer type balance system with varying generalized Chaplygin gas
Authors: Frew J. , Keyser N. , Kim E. , Paddock G. , Toumbleston C. , Wilson S. , Tsikkou C.
Published: September 2024

We consider a system of two balance laws of Keyfitz–Kranzer type with varying generalized Chaplygin gas, which exhibits negative pressure and is a product of a function of time and the inverse of a power of the density. The Chaplygin gas is a fluid designed to accommodate measurements for the early universe and late-time universal expansion while obeying the pressure–density–time relation. We produce an explanation and description of the non-self-similar Riemann solutions, including the non-classical singular solutions. We also find that due to a direct dependence on time, a change in the regions allowing for combinations of classical and non-classical singular solutions occurs; therefore, a Riemann solution can have different solutions over several time intervals. Our findings are confirmed numerically using the Local Lax–Friedrichs scheme.
Magnetic phase transition and cryogenic magnetocaloric properties in the RE6Ni2.3In0.7 (RE = Ho, Er, and Tm) compounds
Authors: Xie Yang , Wang Jinyi , Yang Fuyu , Ying Jiayu , Zhang Yikun
Published: September 2024

The magnetocaloric (MC) properties in many rare-earth (RE)-containing magnetic solids have been intensively investigated, which are aimed to develop suitable candidates for cryogenic magnetic cooling applications and to better understand their intrinsic magnetic characters. We herein fabricated the RE-rich RE6Ni2.3In0.7 (RE = Ho, Er, and Tm) compounds and investigated their structural, magnetic, and MC properties by experimental determination and theoretical calculations. All of these RE6Ni2.3In0.7 compounds crystallize in an Ho6Co2Ga-type structure with an orthogonal Immm space group and order magnetically around the temperatures of 10.6 and 33.0 K for Ho6Ni2.3In0.7, 11.0 K for Er6Ni2.3In0.7, and 7.6 K for Tm6Ni2.3In0.7, respectively. Large cryogenic reversible MC effects were observed in these RE6Ni2.3In0.7 compounds. Moreover, their MC parameters of maximum magnetic entropy changes, relative cooling powers, and temperature-averaged magnetic entropy change are comparable with those of some recently updated cryogenic MC materials.
Emergent time scales of epistasis in protein evolution
Authors: Di Bari Leonardo , Bisardi Matteo , Cotogno Sabrina , Weigt Martin , Zamponi Francesco
Published: September 2024

We introduce a data-driven epistatic model of protein evolution, capable of generating evolutionary trajectories spanning very different time scales reaching from individual mutations to diverged homologs. Our in silico evolution encompasses random nucleotide mutations, insertions and deletions, and models selection using a fitness landscape, which is inferred via a generative probabilistic model for protein families. We show that the proposed framework accurately reproduces the sequence statistics of both short-time (experimental) and long-time (natural) protein evolution, suggesting applicability also to relatively data-poor intermediate evolutionary time scales, which are currently inaccessible to evolution experiments. Our model uncovers a highly collective nature of epistasis, gradually changing the fitness effect of mutations in a diverging sequence context, rather than acting via strong interactions between individual mutations. This collective nature triggers the emergence of a long evolutionary time scale, separating fast mutational processes inside a given sequence context, from the slow evolution of the context itself. The model quantitatively reproduces epistatic phenomena such as contingency and entrenchment, as well as the loss of predictability in protein evolution observed in deep mutational scanning experiments of distant homologs. It thereby deepens our understanding of the interplay between mutation and selection in shaping protein diversity and functions, allows one to statistically forecast evolution, and challenges the prevailing independent-site models of protein evolution, which are unable to capture the fundamental importance of epistasis.
Arf1-dependent LRBA recruitment to Rab4 endosomes is required for endolysosome homeostasis
Authors: Szentgyörgyi Viktória , Lueck Leon Maximilian , Overwijn Daan , Ritz Danilo , Zoeller Nadja , Schmidt Alexander , Hondele Maria , Spang Anne , Bakhtiar Shahrzad
Published: September 2024

Deleterious mutations in the lipopolysaccharide responsive beige-like anchor protein (LRBA) gene cause severe childhood immune dysregulation. The complexity of the symptoms involving multiple organs and the broad range of unpredictable clinical manifestations of LRBA deficiency complicate the choice of therapeutic interventions. Although LRBA has been linked to Rab11-dependent trafficking of the immune checkpoint protein CTLA-4, its precise cellular role remains elusive. We show that LRBA, however, only slightly colocalizes with Rab11. Instead, LRBA is recruited by members of the small GTPase Arf protein family to the TGN and to Rab4+ endosomes, where it controls intracellular traffic. In patient-derived fibroblasts, loss of LRBA led to defects in the endosomal pathway promoting the accumulation of enlarged endolysosomes and lysosome secretion. Thus, LRBA appears to regulate flow through the endosomal system on Rab4+ endosomes. Our data strongly suggest functions of LRBA beyond CTLA-4 trafficking and provide a conceptual framework to develop new therapies for LRBA deficiency.
Quantum walks advantage on the dihedral group for uniform sampling problem
Authors: Dhamapurkar Shyam , Dang Yuhang , Wagh Saniya , Deng Xiu-Hao
Published: September 2024

Random walk algorithms are crucial for sampling and approximation problems in statistical physics and theoretical computer science. The mixing property is necessary for Markov chains to approach stationary distributions and is facilitated by walks. Quantum walks show promise for faster mixing times than classical methods but lack universal proof, especially in finite group settings. Here, we investigate the continuous-time quantum walks on Cayley graphs of the dihedral group D
2n
for odd n, generated by the smallest inverse closed symmetric subset. We present a significant finding that, in contrast to the classical mixing time on these Cayley graphs, which typically takes at least order

Ω
(

n

2

log
(
1

/

2
ϵ
)
)

, the continuous-time quantum walk mixing time on D
2n
is of order

O
(
n

(
log
n
)

5

log
(
1

/

ϵ
)
)

, achieving a quadratic improvement over the classical case. Our paper advances the general understanding of quantum walk mixing on Cayley graphs, highlighting the improved mixing time achieved by continuous-time quantum walks on D
2n
. This work has potential applications in algorithms for a class of sampling problems based on non-abelian groups.