bluuebunny/crossref_metadata_2025 huggingface dataset:
Modeling the dynamics of quantum systems coupled to large-dimensional baths using effective energy states
Authors: Attal Loïse , Falvo Cyril , Calvo Florent , Parneix Pascal
Published: January 2024

The quantum dynamics of a low-dimensional system in contact with a large but finite harmonic bath is theoretically investigated by coarse-graining the bath into a reduced set of effective energy states. In this model, the couplings between the system and the bath are obtained from statistically averaging over the discrete, degenerate effective states. Our model is aimed at intermediate bath sizes in which non-Markovian processes and energy transfer between the bath and the main system are important. The method is applied to a model system of a Morse oscillator coupled to 40 harmonic modes. The results are found to be in excellent agreement with the direct quantum dynamics simulations presented in the work of Bouakline et al. [J. Phys. Chem. A 116, 11118–11127 (2012)], but at a much lower computational cost. Extension to larger baths is discussed in comparison to the time-convolutionless method. We also extend this study to the case of a microcanonical bath with finite initial internal energies. The computational efficiency and convergence properties of the effective bath states model with respect to relevant parameters are also discussed.
Simulation of droplet dynamics in an inclined channel considering contact angle hysteresis using the cascade lattice Boltzmann method
Authors: Zhang Shengting , Li Jing , Zhu Qingyuan , Wu Keliu , Chen Zhangxin , Wang Ziyi
Published: January 2024

Modeling droplet dynamics on solid surfaces with rough or chemically heterogeneous walls is crucial in various industrial applications. In such cases, the downstream and upstream contact lines of the droplet usually move incongruously, leading to droplet deformation known as the contact angle hysteresis (CAH) phenomenon. In this work, we developed a cascaded multicomponent Shan–Chen lattice Boltzmann method to simulate droplet dynamics considering the CAH. Specifically, the Peng–Robinson equation of state is added to one component to improve the density ratio of the model. By modifying the fluid–fluid interaction force scheme, we achieve thermodynamic consistency and independent adjustment of the surface tension. We also implement the modeling of CAH by applying geometric wetting boundaries with a hysteresis window. Based on this model, we first simulated pinned droplets in inclined channels with different hysteresis windows. We obtain the critical tilt angle of the droplet at the onset of sliding, which agrees with the theoretical result. For sliding droplets in the inclined channel, our results reveal that a slight tilt angle is unfavorable for the upstream portion of the droplet sliding, while a large tilt angle is favorable for the entire droplet sliding. A small receding angle results in a large droplet deformation at the quasi-steady state. Finally, by periodically transitioning between different hysteresis windows, enabling exclusive sliding of the upstream contact line during the first half period and subsequent sliding of the downstream contact line during the second half period, we successfully observed the stick-slip phenomenon of the droplet.
Madrid-2019 force field: An extension to divalent cations Sr2+ and Ba2+
Authors: Blazquez S. , Bourg Ian C. , Vega C.
Published: January 2024

In this work, we present a parameterization of Sr2+ and Ba2+ cations, which expands the alkali earth set of cations of the Madrid-2019 force field. We have tested the model against the experimental densities of eight different salts, namely, SrCl2, SrBr2, SrI2, Sr(NO3)2, BaCl2, BaBr2, BaI2, and Ba(NO3)2. The force field is able to reproduce the experimental densities of all these salts up to their solubility limit. Furthermore, we have computed the viscosities for two selected salts, finding that the experimental values are overestimated, but the predictions are still reasonable. Finally, the structural properties for all the salts have been calculated with this model and align remarkably well with experimental observations.
Vapor–liquid–solid synthesis of Ag2Te using chemical vapor deposition method
Authors: Lee Ha Heun , Lee Subin , Hwang Geunwoo , Lee Seungyeon , Cho Suyeon
Published: January 2024

Silver telluride, Ag2Te, has been selectively synthesized by conventional chemical vapor deposition (CVD) via the vapor–liquid–solid growth mechanism. The pre-deposited Ag film on the SiO2/Si substrate was chemically reacted with vaporized Te atoms and transformed into liquid-phase Ag–Te during the CVD process. The appropriate supply of Te vapor to the Ag film influenced the stoichiometry of Ag–Te compounds, and the formation of stoichiometric Ag–Te compounds was well-explained by the phase diagram of the Ag–Te system. We found that Ag2Te was grown in the liquid of Ag–Te under the Te-poor condition, while Ag5Te3 and Te were simultaneously solidified under the Te-rich condition. The high-temperature synthesis of Ag2Te showed higher crystallinity and better stoichiometry than the low-temperature synthesis. This study demonstrates that Ag2Te can be selectively synthesized by conventional CVD via delicate control over the phases of the complex Ag–Te system.
Large elasto-electric response of the charge-ordered perovskite SmBaMn2O6 under an anisotropic strain
Authors: Shen Chun , Zeng Miao , Hou Zekun , Guo Huafei , Jiang Sai , Gu Ding , Su Jian , Zhang Haixiao , Zhang Han
Published: January 2024

The interplay among various order parameters in quantum materials frequently results in exotic ground states and may facilitate revolutionary functional control. In the A-site-ordered manganite double perovskite SmBaMn2O6, it was demonstrated that an anisotropic strain of less than 0.1% can modulate electrical transport by over 6% near the Neel temperature. It is hypothesized that this phenomenon is due to the high sensitivity of spin fluctuation near the antiferromagnetic ordering to lattice distortion, resulting in significant changes in transport properties. This study offers a compelling approach for investigating the interaction between the electric properties of SmBaMn2O6 and in situ anisotropic strain.
Managing flows for frogs: wetland inundation extent and duration promote wetland-dependent amphibian breeding success
Authors: Ocock J. F. , Walcott A. , Spencer J. , Karunaratne S. , Thomas R. F. , Heath J. T. , Preston D.
Published: January 2024

Context River regulation is a key threat to amphibian communities that continue to face global declines. Prior work in regulated river catchments has indicated that wetland inundation from connecting river flows supports breeding in some frog species more than others. Aims Our aim was to identify flow metrics influencing breeding and recruitment success in flow-dependent frogs, to derive flow–ecology relationships. Methods We conducted repeat surveys of frog communities between 2015 and 2020 across two important wetlands in the northern Murray–Darling Basin, Australia. Using random forest analyses, we investigated the influence of 22 explanatory variables on breeding activity and success. Key results Inundation extent was the most important driver of calling activity by flow-dependent species (increasing breeding attempts), whereas the volume of river flows in the preceding months was most important for increasing breeding success. Conclusions Two key features of the flow pulse are linked to breeding success for amphibians in floodplain wetland systems: (1) the size of the pulse as it relates to area of wetland inundated; and (2) the duration of connecting flows as a measure of wetland duration. Implications By establishing amphibian flow–ecology relationships, these species can be included in governmental environmental water objectives and management.
Logic-based mechanistic machine learning on high-content images reveals how drugs differentially regulate cardiac fibroblasts
Authors: Nelson Anders R. , Christiansen Steven L. , Naegle Kristen M. , Saucerman Jeffrey J.
Published: January 2024

Fibroblasts are essential regulators of extracellular matrix deposition following cardiac injury. These cells exhibit highly plastic responses in phenotype during fibrosis in response to environmental stimuli. Here, we test whether and how candidate anti-fibrotic drugs differentially regulate measures of cardiac fibroblast phenotype, which may help identify treatments for cardiac fibrosis. We conducted a high-content microscopy screen of human cardiac fibroblasts treated with 13 clinically relevant drugs in the context of TGFβ and/or IL-1β, measuring phenotype across 137 single-cell features. We used the phenotypic data from our high-content imaging to train a logic-based mechanistic machine learning model (LogiMML) for fibroblast signaling. The model predicted how pirfenidone and Src inhibitor WH-4-023 reduce actin filament assembly and actin–myosin stress fiber formation, respectively. Validating the LogiMML model prediction that PI3K partially mediates the effects of Src inhibition, we found that PI3K inhibition reduces actin–myosin stress fiber formation and procollagen I production in human cardiac fibroblasts. In this study, we establish a modeling approach combining the strengths of logic-based network models and regularized regression models. We apply this approach to predict mechanisms that mediate the differential effects of drugs on fibroblasts, revealing Src inhibition acting via PI3K as a potential therapy for cardiac fibrosis.
Bodily maps of musical sensations across cultures
Authors: Putkinen Vesa , Zhou Xinqi , Gan Xianyang , Yang Linyu , Becker Benjamin , Sams Mikko , Nummenmaa Lauri
Published: January 2024

Emotions, bodily sensations and movement are integral parts of musical experiences. Yet, it remains unknown i) whether emotional connotations and structural features of music elicit discrete bodily sensations and ii) whether these sensations are culturally consistent. We addressed these questions in a cross-cultural study with Western (European and North American, n = 903) and East Asian (Chinese, n = 1035). We precented participants with silhouettes of human bodies and asked them to indicate the bodily regions whose activity they felt changing while listening to Western and Asian musical pieces with varying emotional and acoustic qualities. The resulting bodily sensation maps (BSMs) varied as a function of the emotional qualities of the songs, particularly in the limb, chest, and head regions. Music-induced emotions and corresponding BSMs were replicable across Western and East Asian subjects. The BSMs clustered similarly across cultures, and cluster structures were similar for BSMs and self-reports of emotional experience. The acoustic and structural features of music were consistently associated with the emotion ratings and music-induced bodily sensations across cultures. These results highlight the importance of subjective bodily experience in music-induced emotions and demonstrate consistent associations between musical features, music-induced emotions, and bodily sensations across distant cultures.
Key comparison BIPM.RI(I)-K8 of high dose-rate 192Ir brachytherapy standards for reference air kerma rate of the PTB and the BIPM
Authors: Kessler C , Behrens R , Kasper A , Grote F
Published: January 2024

Main text

An indirect comparison of the standards for reference air kerma rate for 192Ir high dose rate (HDR) brachytherapy sources of the Physikalisch-Technische Bundesanstalt (PTB), Germany, and of the Bureau International des Poids et Mesures (BIPM) was carried out at the PTB in May 2023. The comparison result, based on the calibration coefficients for a transfer standard and expressed as a ratio of the PTB and the BIPM standards for reference air kerma rate, is 1.0022 with a combined standard uncertainty of 0.0101.

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.

The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
Key comparison BIPM.RI(I)-K7 of the air-kerma standards of the BFKH, Hungary, and the BIPM in mammography x-rays
Authors: Kessler C , Burns D , Finta V
Published: January 2024

Main text

A key comparison has been made between the air-kerma standards of the BFKH, Hungary, and the BIPM in mammography x-ray beams. The results show the standards to agree at the level of the expanded uncertainty of the comparison of 9.2 parts in 103. The results are analysed and presented in terms of degrees of equivalence, suitable for entry in the BIPM key comparison database.

To reach the main text of this paper, click on Final Report. Note that this text is that which appears in Appendix B of the BIPM key comparison database https://www.bipm.org/kcdb/.

The final report has been peer-reviewed and approved for publication by the CCRI, according to the provisions of the CIPM Mutual Recognition Arrangement (CIPM MRA).
The non-linear perturbation of a black hole by gravitational waves. III. Newman–Penrose constants
Authors: Frauendiener J , Goodenbour A , Stevens C
Published: January 2024

In this paper we continue our study of the non-linear response of a Schwarzschild black hole to an ingoing gravitational wave by computing the Newman–Penrose (NP) constants. The NP constants are five complex, supertranslation-invariant quantities defined on null infinity

I

+

and although put forward in the 60’s, they have never been computed in a non-stationary setting. We accomplish this through a numerical implementation of Friedrich’s generalized conformal field equations whose semi-global evolution yields direct access to

I

+

. The integral expressions for the NP constants as given originally are expressed in a general gauge to enable their computation from numerically generated data. Canonical methods of fixing inherent degrees of freedom in their definitions are discussed. The NP expressions are then computed for a variety of different ingoing wave profiles in axisymmetry, and then with no symmetry assumptions in a general

3
+
1

setting for which all five complex quantities are non-zero. We discuss the consequence of the (numerical) constancy of the NP expressions for the (non)-smoothness of null-infinity.
EVStabilityNet: predicting the stability of star clusters in general relativity
Authors: Straub Christopher , Wolfschmidt Sebastian
Published: January 2024

We present a deep neural network which predicts the stability of isotropic steady states of the asymptotically flat, spherically symmetric Einstein–Vlasov system in Schwarzschild coordinates. The network takes as input the energy profile and the redshift of the steady state. Its architecture consists of a U-Net with a dense bridge. The network was trained on more than ten thousand steady states using an active learning scheme and has high accuracy on test data. As first applications, we analyze the validity of physical hypotheses regarding the stability of the steady states.
β-Ga2O3 nanotube arrays for high-performance self-powered ultraviolet photoelectrochemical photodetectors
Authors: Ding Shan , Chen Kai , Xiu Xiangqian , Shao Pengfei , Xie Zili , Tao Tao , Liu Bin , Chen Peng , Chen Dunjun , Zhang Rong , Zheng Youdou
Published: January 2024

Self-powered ultraviolet (UV) photodetectors (PDs) are critical for future energy-efficient optoelectronic systems due to their low energy consumption and high sensitivity. In this paper, the vertically aligned β-Ga2O3 nanotube arrays (NTs) have been prepared on GaN/sapphire substrate by the thermal oxidation process combined with the dry etching technology, and applied in the UV photoelectrochemical photodetectors (PEC-PDs) for the first time. Based on the large specific surface area of β-Ga2O3 NTs on GaN/sapphire substrates and the solid/liquid heterojunction, the PEC-PDs exhibit excellent self-powered characteristics under 255 nm (UVA) and 365 nm (UVC) light illumination. Under 255 nm (365 nm) light illumination, the maximum responsivity of 49.9 mA W−1 (32.04 mA W−1) and a high detectivity of 1.58 × 1011 Jones (1.01 × 1011 Jones) were achieved for the β-Ga2O3 NTs photodetectors at 0 V bias. In addition, the device shows a fast rise/decay time of 8/4 ms (4/2 ms), which is superior to the level of the previously reported self-powered UV PEC-PDs. This high-performance PEC-PD has potential applications in next-generation low-energy UV detection systems.
Biomass carbon and Ti2C3MXene quantum dots as ratiometric fluorescent probes for sensitive detecting malachite green in fish sample
Authors: Wang Xiaoyan , Luo Xiaoling , Zou Pintian , Lv Yi-ju , Kong Xiangfei , Huang Yue , Liu Zheng , Han Guo-Cheng
Published: January 2024

A visual detection method for malachite green (MG) in food was established based on ‘double-response-OFF’ ratiometric fluorescent paper-based sensor. Biomass carbon quantum dots (BCQDs) using broad bean shell, and Ti3C2MXene quantum (MQDs) dots modified by ethylenediamine were synthesized by solvothermal method. The MG and two kinds of quantum dots could undergo static quenching, and the fluorescence color of two kinds of quantum dots gradually changed from red to blue, eventually the fluorescence was quenched, and the pattern had a two-stage linear relationship using fluorescent spectrofluorometer in the range of 0.1–140.0 μM and the detection limit of 0.07 μM. On this basis, a BCQDs/MQDs ratiometric fluorescence paper-based sensor was constructed and applied to fish sample. Through mobile phone software-Color recognizer, RGB values of fluorescent paper-based sensor at various concentrations of MG were extracted. The results showed that MG concentration was linearly correlated with R’ value of RGB in the range of 20.0–140.0 μM with 16.5 μM detection limit. The method had been applied to the determination of canned fish and fresh basa fish samples, and the recovery rates were 97.33%–108.93% and 96.04%–117.97%, respectively. It proved that the ratiometric fluorescent paper-based sensor could be used for the rapid visual quantitative detecting MG in real samples.
Large-area, size-controlled and transferable graphene oxide-metal films for humidity sensor
Authors: Zhu Xiaobin , Zhou Zhengcun , Zhang Jinlei , Wu Shuyi
Published: January 2024

The lack of low-cost methods to synthesize large-area graphene-based materials is still an important factor that limits the practical application of graphene devices. Herein, we present a facile method for producing large-area graphene oxide-metal (GO–M) films, which are size controllable and transferable. The sensor constructed using the GO–M film exhibited humidity sensitivity while being unaffected by pressure. The relationship between the sensor’s resistance and relative humidity followed an exponential trend. The GO–Mg sensor was the most sensitive among all the tested sensors. The facile synthesis of GO–M films will accelerate the widespread utilization of graphene-based materials.
Discrete residual diffusion model for high-resolution prostate MRI synthesis
Authors: Han Zhitao , Huang Wenhui
Published: January 2024

Objective. High-resolution magnetic resonance imaging (HR MRI) is an effective tool for diagnosing PCa, but it requires patients to remain immobile for extended periods, increasing chances of image distortion due to motion. One solution is to utilize super-resolution (SR) techniques to process low-resolution (LR) images and create a higher-resolution version. However, existing medical SR models suffer from issues such as excessive smoothness and mode collapse. In this paper, we propose a novel generative model avoiding the problems of existing models, called discrete residual diffusion model (DR-DM). Approach. First, the forward process of DR-DM gradually disrupts the input via a fixed Markov chain, producing a sequence of latent variables with increasing noise. The backward process learns the conditional transit distribution and gradually match the target data distribution. By optimizing a variant of the variational lower bound, training diffusion models effectively address the issue of mode collapse. Second, to focus DR-DM on recovering high-frequency details, we synthesize residual images instead of synthesizing HR MRI directly. The residual image represents the difference between the HR and LR up-sampled MR image, and we convert residual image into discrete image tokens with a shorter sequence length by a vector quantized variational autoencoder (VQ-VAE), which reduced the computational complexity. Third, transformer architecture is integrated to model the relationship between LR MRI and residual image, which can capture the long-range dependencies between LR MRI and the synthesized imaging and improve the fidelity of reconstructed images. Main results. Extensive experimental validations have been performed on two popular yet challenging magnetic resonance image super-resolution tasks and compared to five state-of-the-art methods. Significance. Our experiments on the Prostate-Diagnosis and PROSTATEx datasets demonstrate that the DR-DM model significantly improves the signal-to-noise ratio of MRI for prostate cancer, resulting in greater clarity and improved diagnostic accuracy for patients.
Partial volume correction of PET image data using geometric transfer matrices based on uniform B-splines
Authors: Mandeville Joseph B , Efthimiou Nikos , Weigand-Whittier Jonah , Hardy Erin , Knudsen Gitte M , Jørgensen Louise M , Chen Yin-Ching I
Published: January 2024

Objective. Most methods for partial volume correction (PVC) of positron emission tomography (PET) data employ anatomical segmentation of images into regions of interest. This approach is not optimal for exploratory functional imaging beyond regional hypotheses. Here, we describe a novel method for unbiased voxel-wise PVC. Approach. B-spline basis functions were combined with geometric transfer matrices to enable a method (bsGTM) that provides PVC or alternatively provides smoothing with minimal regional crosstalk. The efficacy of the proposed method was evaluated using Monte Carlo simulations, human PET data, and murine functional PET data. Main results. In simulations, bsGTM provided recovery of partial volume signal loss comparable to iterative deconvolution, while demonstrating superior resilience to noise. In a real murine PET dataset, bsGTM yielded much higher sensitivity for detecting amphetamine-induced reduction of [11C]raclopride binding potential. In human PET data, bsGTM smoothing enabled increased signal-to-noise ratios with less degradation of binding potentials relative to Gaussian convolution or non-local means. Significance. bsGTM offers improved performance for PVC relative to iterative deconvolution, the current method of choice for voxel-wise PVC, especially in the common PET regime of low signal-to-noise ratio. The new method provides an anatomically unbiased way to compensate partial volume errors in cases where anatomical segmentation is unavailable or of questionable relevance or accuracy.
Setup and characterisation according to NEMA NU 4 of the phenoPET scanner, a PET system dedicated for plant sciences
Authors: Hinz Carsten , Jahnke Siegfried , Metzner Ralf , Pflugfelder Daniel , Scheins Jürgen , Streun Matthias , Koller Robert
Published: January 2024

Objective. The phenoPET system is a plant dedicated positron emission tomography (PET) scanner consisting of fully digital photo multipliers with lutetium–yttrium oxyorthosilicate crystals and located inside a custom climate chamber. Here, we present the setup of phenoPET, its data processing and image reconstruction together with its performance. Approach. The performance characterization follows the national electrical manufacturers association (NEMA) standard for small animal PET systems with a number of adoptions due to the vertical oriented bore of a PET for plant sciences. In addition temperature stability and spatial resolution with a hot rod phantom are addressed. Main results. The spatial resolution for a 22Na point source at a radial distance of 5 mm to the center of the field-of-view (FOV) is 1.45 mm, 0.82 mm and 1.88 mm with filtered back projection in radial, tangential and axial direction, respectively. A hot rod phantom with 18F gives a spatial resolution of up to 1.6 mm. The peak noise-equivalent count rates are 550 kcps @ 35.08 MBq, 308 kcps @ 33 MBq and 45 kcps @ 40.60 MBq for the mouse, rat and monkey size scatter phantoms, respectively. The scatter fractions for these phantoms are 12.63%, 22.64% and 55.90%. We observe a peak sensitivity of up to 3.6% and a total sensitivity of up to S

A,tot
= 2.17%. For the NEMA image quality phantom we observe a uniformity of %STD = 4.22% with ordinary Poisson maximum likelihood expectation-maximization with 52 iterations. Here, recovery coefficients of 0.12, 0.64, 0.89, 0.93 and 0.91 for 1 mm, 2 mm, 3 mm, 4 mm and 5 mm rods are obtained and spill-over ratios of 0.08 and 0.14 for the water-filled and air-filled inserts, respectively. Significance. The phenoPET and its laboratory are now in routine operation for the administration of [11C]CO2 and non-invasive measurement of transport and allocation of 11C-labelled photoassimilates in plants.
Absolute atomic nitrogen density spatial mapping in three MHCD configurations
Authors: Remigy Alice , Menacer Belkacem , Kourtzanidis Konstantinos , Gazeli Odhisea , Gazeli Kristaq , Lombardi Guillaume , Lazzaroni Claudia
Published: January 2024

In this work, nanosecond two-photon absorption laser induced fluorescence (TALIF) is used to perform spatial mappings of the absolute density of nitrogen atoms generated in a micro-hollow cathode discharge (MHCD). The MHCD is operated in the normal regime, with a DC discharge current of 1.6 mA and the plasma is ignited in a 20% Ar/ 80% N2 gas mixture. A 1-inch diameter aluminum substrate, acting as a third electrode (second anode), is placed further away from the MHCD to emulate a deposition substrate. The spatial profile of the N atoms is measured in three MHCD configurations. First, we study a MHCD having the same pressure (50 mbar) on both sides of the anode/cathode electrodes and the N atoms simply diffuse in three dimensions from the MHCD. The recorded N atoms density profile in this case satisfies our expectations, i.e. the maximal density is found at the axis of the hole, close to the MHCD. However, when we introduce a pressure differential, thus creating a plasma jet, an unexpected N atoms distribution is measured with maximum densities away from the jet axis. This behavior cannot be simply explained by the TALIF measurements. Then, as a first simplified approach in this work, we turn our attention to the role of the gas flow pattern. Compressible gas flow simulations show a correlation between the jet width and the radial distribution of the N atoms at different axial distances from the gap. Finally, a DC positive voltage is applied to the third electrode (second anode), which ignites a micro cathode sustained discharge (MCSD). The presence of the pressure differential unveils two stable working regimes depending on the current repartition between the two anodes. The MCSD enables an homogenization of the density profile along the surface of the substrate, which is suitable for nitride deposition applications.
First principle studies on half-metallicity and pressure-induced half-metallic band gap in 3-d transition metal-based quaternary Heusler ScVCoZ (Z = Si, Ge, Sn, P, As, and Sb) alloys
Authors: Puthusseri Narayanan Namboodiri , Natesan Baskaran
Published: January 2024

In the present work, we predict a series of 3-d transition metals-based quaternary Heusler alloys (QHA) ScVCoZ (Z = Si, Ge, Sn, P, As, and Sb) (SVCZ), by employing density functional theory (DFT) calculations. We carried out extensive band structure (BS) and density of states (DOS) analysis to explain the half-metallic and magnetic behavior of the alloys. We found that SVCZ alloys stabilize in the F

4

̅

3m space group and exhibit a ferromagnetic (FM) ground state (GS). Among the QHAs, SVCZ (Z = Si, Ge, and Sb) exhibit intriguing half-metallic properties featuring 100% spin polarization at the Fermi level (EF). Additionally, the effect of pressure indicates a band gap opening in one of the spin channels for SCVZ (Z = P, and As), and the half-metallic characteristics are retained up to a compressive pressure, respectively of 65, and 79 GPa for SCVP and SCVAs. Elastic properties calculations suggest SVCZ alloys satisfy Born stability criteria and are mechanically stable. Among the predicted QHAs, SVCZ (Z = Si, Ge, and Sn) shows brittle nature, whereas SVCZ (Z = P, As, and Sb) are ductile.
Optical soliton solutions of fokas system and (2 + 1) Davey-Stewartson system by mapping method
Authors: Ahmed Naveed , Rani Mehwish , Dragomir Silvestru Sever , Bin Mohsin Bandar
Published: January 2024

In this article, a very effective technique called generalized auxiliary equation mapping method has been employed to investigate some very important nonlinear equations in optical fibers such as Fokas system and

(
2
+
1
)

Davey-Stewartson (DS) system. Under different situations, the obtained solutions exhibit various wave pattern like bright and dark soliton, kink soliton, periodic wave soliton and singular solitons. These solutions are novel and interesting and prove the efficiency of the method. The accuracy of the obtained results provides the competence of the method and ensures that it can be used for other mathematical models involved in optical fibers. Graphical simulation of some reported results has been discussed here to visualize and support the mathematical results in terms of 3D, 2D and contour plots.
Tunneling of rotational black string with nonlinear electromagnetic fields
Authors: Mirekhtiary F S , Abbasi A , Hosseini K , Tulucu F
Published: January 2024

In the background of anti-de Sitter spaces, a novel solution of a rotating black string (RBS) attributed to a nonlinear electromagnetic field has been derived. The authors have deciphered two metric functions which are called RBS1 and RBS2. The two real roots, the two metrics (RBS1 and RBS2), have been found based on Newton–Raphson method. Furthermore, the Hawking radiation of scalar particles has been studied by employing the Hamilton–Jacobi (HJ) method to calculate the Hawking temperature of RBS1 and RBS2.
Thermal-contact capacity of one-dimensional attractive Gaudin–Yang model
Authors: Zhang 张 Xiao-Min 小敏 , Cheng 程 Song 颂 , Chen 陈 Yang-Yang 洋洋
Published: January 2024

Tan’s contact

C

is an important quantity measuring the two-body correlations at short distances in a dilute system. Here we make use of the technique of exactly solved models to study the thermal-contact capacity

K
T

, i.e., the derivative of

C

with respect to temperature in the attractive Gaudin–Yang model. It is found that

K
T

is useful in identifying the low temperature phase diagram, and using the obtained analytical expression of

K
T

, we study its critical behavior and the scaling law. Especially, we show

K
T

versus temperature and thus the non-monotonic tendency of

C

in a tiny interval, for both spin-balanced and imbalanced phases. Such a phenomenon is merely observed in multi-component systems such as SU(2) Fermi gases and spinor bosons, indicating the crossover from the Tomonaga–Luttinger liquid to the spin-coherent liquid.
Co-doped BaFe2As2 Josephson junction fabricated with a focused helium ion beam
Authors: Chen 陈 Ziwen 紫雯 , Zhang 张 Yan 焱 , Ma 马 Ping 平 , Xu 徐 Zhongtang 中堂 , Li 李 Yulong 宇龙 , Wang 王 Yue 越 , Lu 路 Jianming 建明 , Ma 马 Yanwei 衍伟 , Gan 甘 Zizhao 子钊
Published: January 2024

Josephson junction plays a key role not only in studying the basic physics of unconventional iron-based superconductors but also in realizing practical application of thin-film based devices, therefore the preparation of high-quality iron pnictide Josephson junctions is of great importance. In this work, we have successfully fabricated Josephson junctions from Co-doped BaFe2As2 thin films using a direct junction fabrication technique which utilizes high energy focused helium ion beam (FHIB). The electrical transport properties were investigated for junctions fabricated with various He+ irradiation doses. The junctions show sharp superconducting transition around 24 K with a narrow transition width of 2.5 K, and a dose correlated foot-structure resistance which corresponds to the effective tuning of junction properties by He+ irradiation. Significant J
c suppression by more than two orders of magnitude can be achieved by increasing the He+ irradiation dose, which is advantageous for the realization of low noise ion pnictide thin film devices. Clear Shapiro steps are observed under 10 GHz microwave irradiation. The above results demonstrate the successful fabrication of high quality and controllable Co-doped BaFe2As2 Josephson junction with high reproducibility using the FHIB technique, laying the foundation for future investigating the mechanism of iron-based superconductors, and also the further implementation in various superconducting electronic devices.
Spike sorting in the presence of stimulation artifacts: a dynamical control systems approach
Authors: Shokri Mohammad , Gogliettino Alex R , Hottowy Paweł , Sher Alexander , Litke Alan M , Chichilnisky E J , Pequito Sérgio , Muratore Dante
Published: January 2024

Objective. Bi-directional electronic neural interfaces, capable of both electrical recording and stimulation, communicate with the nervous system to permit precise calibration of electrical inputs by capturing the evoked neural responses. However, one significant challenge is that stimulation artifacts often mask the actual neural signals. To address this issue, we introduce a novel approach that employs dynamical control systems to detect and decipher electrically evoked neural activity despite the presence of electrical artifacts. Approach. Our proposed method leverages the unique spatiotemporal patterns of neural activity and electrical artifacts to distinguish and identify individual neural spikes. We designed distinctive dynamical models for both the stimulation artifact and each neuron observed during spontaneous neural activity. We can estimate which neurons were active by analyzing the recorded voltage responses across multiple electrodes post-stimulation. This technique also allows us to exclude signals from electrodes heavily affected by stimulation artifacts, such as the stimulating electrode itself, yet still accurately differentiate between evoked spikes and electrical artifacts. Main results. We applied our method to high-density multi-electrode recordings from the primate retina in an ex vivo setup, using a grid of 512 electrodes. Through repeated electrical stimulations at varying amplitudes, we were able to construct activation curves for each neuron. The curves obtained with our method closely resembled those derived from manual spike sorting. Additionally, the stimulation thresholds we estimated strongly agreed with those determined through manual analysis, demonstrating high reliability (

R
2

=
0.951

for human 1 and

R
2

=
0.944

for human 2). Significance. Our method can effectively separate evoked neural spikes from stimulation artifacts by exploiting the distinct spatiotemporal propagation patterns captured by a dense, large-scale multi-electrode array. This technique holds promise for future applications in real-time closed-loop stimulation systems and for managing multi-channel stimulation strategies.
Creating equilibrium glassy states via random particle bonding
Authors: Ozawa Misaki , Barrat Jean-Louis , Kob Walter , Zamponi Francesco
Published: January 2024

Creating amorphous solid states by randomly bonding an ensemble of dense liquid monomers is a common procedure that is used to create a variety of materials, such as epoxy resins, colloidal gels, and vitrimers. However, the properties of the resulting solid do a priori strongly depend on the preparation history. This can lead to substantial aging of the material; for example, properties such as mechanical moduli and transport coefficients rely on the time elapsed since solidification, which can lead to a slow degradation of the material in technological applications. It is therefore important to understand under which conditions random monomer bonding can lead to stable solid states, that is, long-lived metastable states whose properties do not change over time. This work presents a theoretical and computational analysis of this problem and introduces a random bonding procedure that ensures the proper equilibration of the resulting amorphous states. Our procedure also provides a new route to investigate the fundamental properties of glassy energy landscapes by producing translationally invariant ultrastable glassy states in simple particle models.
Mechanical switches integrated sandwich triboelectric nanogenerator with high instantaneous output power
Authors: Wu Han , Liao Ruijin , Wang Jiyu
Published: January 2024

Triboelectric nanogenerator (TENG) has emerged as a promising energy harvester that converts random mechanical energy in the environment into electricity to enable self-powered system construction. However, the conventional TENG exhibits a large internal resistance resulting in a low output power across external loads for practical application. In this work, the travel mechanical switches were integrated into the TENG to boost output power, where the switches were turned on and off by the periodic motion between the triboelectric layers. Moreover, the triboelectric layers of TENG were developed as contact separation sandwich structures to work with mechanical switches, allowing the device to release the co-accumulated charges from the dual triboelectric layer to yield giant instantaneous discharge. Compared to a conventional TENG, the device offers ~2.8 times more transfer charge in one cycle and ~106 times more instantaneous power at an external load of 500 Ω, which renders the internal impedance match almost negligible. As a result, the high-power source demonstrates the ability to illuminate the commercial lamps in parallel (total power: 50 W). Such a unique TENG with high output power for low resistance load could greatly enrich the practical application fields of self-powered systems.
The flame retardancy and mechanical properties of waste polyester fabric/hemp stalk composites modified with piperazine pyrophosphate and ammonium polyphosphate
Authors: Li F , Shi Y R , Liu J T , Cui Z , Lu Y Z , Niu M , Xue B X
Published: January 2024

The piperazine pyrophosphate (PAPP) and ammonium polyphosphate (APP) were employed to enhance the flame retardancy of waste polyester/hemp stalk composites. And the impact of PAPP/APP flame retardants on the flame retardancy and mechanical properties of waste polyester/hemp stalk was investigated. The results indicated that the PAPP/APP combination offered superior flame retardancy, with minimal impact on the composites’ bending property. Notably, when the total addition of PAPP/APP was 25%, with a mass ratio of 1 to 1, the limiting oxygen index (LOI) value of the PAPP/APP/waste polyester/hemp stalk composite material increased significantly from 18.8% to 27.1%, achieving the flame retardant level. Correspondingly, the vertical combustion level attained V-0 level, and the charring rate at 600°C escalated from the initial 25.8% to 32.5%. Remarkably, both the bending strength and modulus of PAPP/APP/waste polyester/hemp stalk composites remained stable.
Hybrid directed energy deposition process coupled with plastic deformation
Authors: Yang J X , Wang R , Hu X Q , Wu M Y , Rao H , Bi Y J
Published: January 2024

Laser directed energy deposition (LDED) process has unique advantage in rapid forming of large-sized metal components, gradient material/structural components, or repairing/remanufacturing worn parts. However, the high residual stress and strong anisotropy in mechanical properties of the as-deposit components limit the application of LDED technology in the manufacturing of key structural components. To overcome these problems, various hybrid additive manufacturing (HAM) technologies have been developed, such as plastic deformation, ultrasonic or magnetic field assisted LDED processes to improve the quality and the mechanical properties, where these coupled processes are carried out either simultaneously or cyclically with the LDED process. The hybrid additive manufacturing, while retaining the advantages of individual forming process, avoids the mutual interference between each process and reducing the adverse effects generated if used separately. Hybrid additive manufacturing processes fundamentally change the underlying physical mechanisms of molten pool dynamics, microstructural evolution, temperature and thermal stress gradient in additive manufacturing, thereby optimizing the microstructure and performance of the manufactured components. In this paper, the key technical features of the hybrid additive manufacturing process coupled with plastic deformation were described in details, and the resulting differences in microstructure, residual stress, and mechanical properties of the prepared samples were systematically analyzed. The developing trend of hybrid additive manufacturing processes in coupling mechanisms, parameter optimization, and equipment have been discussed.
Quantitative study of high-frequency fatigue hole-edge stresses in nickel-based single-crystal superalloy
Authors: Li Leyu , Li Zheng , Liu Jiabin , Zhang Jingang , Deng Zhiwei , Li Quanwei , Liu Xinling
Published: January 2024

In this paper, the influence of air film holes on the stress distribution of nickel-based single-crystal superalloy blades is investigated, a simulated test piece is designed for the analysis and test of the stress distribution of air film holes, and a method of quantitative inverse inference of the stress at the edge of the air film holes is proposed. Finite element simulation of high circumferential vibration fatigue of the simulated test piece was carried out by ANSYS to obtain the gradient of stress distribution at the hole edge. The EBSD technique was used to measure the dimensions of the plastic zone in the region near the fracture, and the quantitative fatigue stresses were extrapolated using a crack tip plastic zone model with Tresca yield criterion. The compressive stress exerted by the femtosecond laser perforation method on the air film aperture wall was detected by the nanoindentation technique, and the residual stress was analysed using the S. Suresh computational model. The results of this study show that based solely on finite element simulation, it is not possible to completely simulate the effect of residual stresses caused by machining on fatigue fracture, which in turn leads to a lack of conformity between the results of finite element simulation and the results of the inverse plastic zone size extrapolation; however, the stress magnitude at the edge of the hole can be well computed by combining the stress concentration coefficients from finite element simulation with the stresses from the inverse plastic zone size extrapolation after taking into account the residual stresses from machining. The quantitative analysis results of this method have an error within 1.3 times the dispersion band compared to the test data.
Research on the construction and properties of waste cotton cellulose/carbon dots composite antibacterial hydrogel
Authors: Liu J , Liu Y , Zhang C Y , Shao Z Y , Niu M , Xue B X
Published: January 2024

The recycling and utilization of waste cotton fabrics is of great significance to implement green pollution reduction and carbon reduction. In order to realize the high value-added utilization of waste cotton cellulose (WCC) by introducing new carbon dots (CDs), WCC/CDs composite hydrogel with good antibacterial effect were prepared for the application in the field of antibacterial dressings. WCC/CDs composite hydrogel formed by doping different contents of carbon dots (CDs) with WCC hydrogel as raw material and epichlorohydrin (EPI) as crosslinking agent. The structure was characterized by X-ray diffraction (XRD) and infrared spectrum analysis, the antibacterial properties and swelling properties of WCC/CDs composite hydrogel were tested. The results show that the addition of CDs promoted the gelation of WCC hydrogel, enhanced its structure stability and endowed it with antibacterial properties. WCC/CDs composite hydrogel with 10wt% CDs was more stable, and its modulus reached 91 KPa. Compared with WCC hydrogel the swelling performance of WCC/CDs composite hydrogel was improved, and the swelling rate was 16.81 g·g-1. By destroying the cellular structure of bacteria and promoting the production of ROS, the inhibition rate of E. coil and S. aureus was more than 99%.
Stability of the microstructure and properties of Ti2AlNb alloys under thermal exposure conditions
Authors: Wei Z W , Ma L , You L , Liu C K
Published: January 2024

In this paper, the microstructure and property stability of Ti2AlNb alloy specimens treated by thermal exposure at 800°C for 0~12h were investigated using universal tensile tester, X-ray diffractometer, scanning electron microscope, electron backscattering diffraction, and in-situ tensile scanning electron microscope. The results show that with the extension of thermal exposure time, the tensile strength and yield strength of the alloy slightly increased, the B2-phase of the alloy decreased while the O-phase increased, and the content of the α2-phase also slightly decreased. It has been found that the properties changes are related to the changes of microstructure. The tensile cracks expanded along the grain boundaries between the O-phase and B2-phase as well as along the O-phase grain boundaries. The slight changes in microstructure and properties indicate that the Ti2AlNb alloy is stable and reliable for short-term service at 800 °C.
Effects of different treatment processes on microstructure and tensile fracture behaviour of selected laser melting TC17 titanium alloy
Authors: Jiang T , Dong X Y , Chen H H , Sun B B
Published: January 2024

It is essential to study the tensile fracture mechanism of additively manufactured materials and develop the effective process treatment techniques to improve their fracture resistance. In this paper, the effects of different treatment processes on the microstructure and tensile fracture properties of TC17 titanium alloy melted by laser selective zone melting were investigated. The static tensile fracture morphological characteristics were observed by combining SEM and EDS. The metallographic microstructure after chemical corrosion was observed optically. And the tensile fracture morphology of the three states of TC17 titanium alloy samples at room temperature conditions was investigated. The results show that the metallographic matrix microstructure of TC17 titanium alloy after HT, HIP and HIP-HT treatments was a bimodal structure with α+β phases, i.e., β phase was in the form of a net basket, and α phase was in the form of a coarse bar. The grain sizes of the samples treated by different processes were different, but the difference in grain size of the HT-treated tissues was small, and the difference in grain size of the HIP-HT-treated tissues was large. And the coarse α-phase segregation could be seen at the edge of the samples. The 3D-printed materials had complex changes in anisotropic properties affected by the printing structure and tissue. The printed tissues were brittle and had high internal stresses. These problems were partly improved at high temperatures, but they still existed. The HIP-HT-treated materials had a large α+β-phase bimodal structure. The HT-treated material had coarse grains and precipitation phases, poor room temperature plasticity, and improved high temperature plasticity. After HT treatment, the original printing microstructure changed, the strength and plasticity were significantly improved, but the macroscopic printing structure still had a slight influence on the fracture morphology. When HIP treatment temperature was higher, the influence of macroscopic printing structure basically disappeared, but the grain and microstructure grew up, and the strength and plasticity were slightly lower than that of the HT treatment. HIP process basically eliminated the unfused defects of the three-dimensional morphology, and the local weak bonding zone formed.