bluuebunny/crossref_metadata_2025_split huggingface dataset:
Properties of NbxTi(1−x)N thin films deposited on 300 mm silicon wafers for upscaling superconducting digital circuits
Authors: Lozano Daniel Pérez , Soulié Jean-Philippe , Hodges Blake , Piao Xiaoyu , O’Neal Sabine , Valente-Feliciano Anne-Marie , Herr Quentin , Tőkei Zsolt , Kim Min-Soo , Herr Anna 
Published: May 2024

Abstract
Scaling superconducting digital circuits requires fundamental changes in the current material set and fabrication process. The transition to 300 mm wafers and the implementation of advanced lithography are instrumental in facilitating mature CMOS processes, ensuring uniformity, and optimizing the yield. This study explores the properties of Nb
x
Ti(1−x)N films fabricated by magnetron DC sputtering on 300 mm Si wafers. As a promising alternative to traditional Nb in device manufacturing, Nb
x
Ti(1−x)N offers numerous advantages, including enhanced stability and scalability to smaller dimensions, in both processing and design. As a ternary material, Nb
x
Ti(1−x)N allows engineering material parameters by changing deposition conditions. The engineered properties can be used to modulate device parameters through the stack and mitigate failure modes. We report characterization of Nb
x
Ti(1−x)N films at less than 2% thickness variability, 2.4% T
c variability and 3% composition variability. Film resistivity (140–375 Ωcm) shows a strong correlation with the film oxygen content, while the critical temperature T
c (4.6 K–14.1 K) is strongly affected by film stoichiometry and its microstructure has only a moderate effect on modifying T
c. Our results offer insights about the interplay between film stoichiometry, film microstructure and critical temperature.
Using machine learning to predict gamma shielding properties: a comparative study
Authors: Nahool T A , Abdelmonem A M , Ali M S , Yasser A M 
Published: May 2024

Abstract
This study employed machine learning (ML) algorithms to predict the linear attenuation coefficients (LACs) of materials in inorganic scintillation detectors, which are crucial for evaluating self-shielding properties. Predictions from various ML models were compared with results from the Phy-X/PSD program across different photon energies. The Gradient Boosting Regressor (GBR) model was identified as the most accurate model, achieving a testing set accuracy of 96.40%. This research showcases the potential of ML for efficiently and accurately estimating LACs, with the GBR model showing promise for applications in radiation detection and material science.
Effect of relaxation on the transfer of orbital angular momentum via four-wave mixing process in the four-level double lambda atomic system
Authors: Kumar Rohit , Manchaiah Dixith , Ahmad Mobassir , Easwaran Raghavan K 
Published: May 2024

Abstract
In this work, we have theoretically studied the resonant four-wave mixing (FWM) in a four-level double Lambda (Λ) atomic system in connection with orbital angular momentum (OAM) transfer from probe to generated signal beam. The effect of the relaxation process is studied in the forward as well as backward FWM. Based on the semiclassical model, our analysis shows a strong dependence of conversion efficiency on spontaneous decay and decoherence rates. From the intensity and phase profile, we have confirmed the OAM nature of the generated signal beam. The physical explanation is given for the dependence of efficiency on the decay rate of the excited atomic state. We have shown that decoherence present in the system always leads to a deleterious effect on conversion efficiency. Our presentation treats forward and backward FWM in a unified way in the context of OAM transfer and sheds light on the parameter dependence of conversion efficiency.
An excellent super-polarization-independent optical directional coupler based on dual-core photonic crystal fibre with a bandwidth of 390 nm
Authors: Zou Hui , Xu Jianjie , Jiang Menglin , Chen Yu 
Published: May 2024

Abstract
In this work, a novel structure of dual-core photonic crystal fibre (PCF) is proposed to realize the super-polarization-independent optical directional coupler, based on the feasibility of optical fibre manufacturing process and the need of practical application into account. The introduced fluorine-doped elliptical cores with a rotation angle of 45 degrees successfully realize the super-polarization-independent coupling performance within the effective wavelength range of 1230–1620 nm, with a difference in coupling ratios between two polarized lights of less than 0.004%. In other words, it counteracts the negative effects of the introduction of dual cores on the structure’s symmetry. This greatly reduces the difference in coupling ratio between the two polarization states and effectively eliminates the polarization-dependence of the dual-core PCF. In addition, when compared to traditional elliptical air holes, the solid elliptical structure offers greater ease of control, making manufacturing less challenging. Consequently, this innovative structure is poised for widespread adoption in today’s optical communication networks.
Reversible image secret sharing based on quantum logistic mapping and Chinese remainder theorem
Authors: Yang Yu-Guang , Liu Chang , Zhou Yi-Hua , Shi Wei-Min , Jiang Dong-Hua , Liao Xin 
Published: May 2024

Abstract
A reversible image secret sharing algorithm is proposed based on quantum logistic mapping and Chinese remainder theorem. In this algorithm, the hash value of the original image is generated using the SHA-3 algorithm, and then encrypted using the RSA algorithm to obtain the encrypted hash value and the public key, which are the initial values in the quantum logistic mapping equations. Next, the quantum logistic mapping algorithm will be utilized to generate the chaotic sequence. After scrambling the original image matrix with the chaotic sequence, the pre-encryption part will be completed. Finally, the cover images are binarized and then the pre-encrypted secret image is embedded into them, adding the Chinese remainder theorem. According to the simulation results, the present algorithm improves the key sensitivity of Chinese remainder theorem-based image secret sharing and has high robustness to salt and pepper noise and cut-off attack.
Research on water equivalence and angle dependence of medical POF scintillation dosimeters
Authors: Yu Junchang , Zhang Qing , Zhao Kexin , Zhang Hongquan 
Published: May 2024

Abstract
In radiation dosimetry and medical dosimetry, optical fiber dosimeters have great advantages in application due to their small size and long transmission distance. However, in some low-dose radiation environments, the water inequivalence error and angle error of optical fiber dosimeters can have significant impacts that cannot be ignored. In this paper, the effects of ray energy, ray solid angle and optical fiber probe size on water inequivalence error and angle error are analyzed by using Monte Carlo simulation. Due to the complexity of the influencing factors of the angle error, which is difficult to be analyzed precisely and quantitatively, a correction method based on BP neural network is proposed. The final validation results demonstrate that the correction scheme can reduce the total angle error of the optical fiber dosimeter to

2.72
%
.
Semiclassical dynamics of a superconducting circuit: chaotic dynamics and fractal attractors
Authors: Stirpe Davide , Manninen Juuso , Massel Francesco 
Published: May 2024

Abstract
We study here the semiclassical dynamics of a superconducting circuit constituted by two Josephson junctions in series, in the presence of a voltage bias. We derive the equations of motion for the circuit through a Hamiltonian description of the problem, considering the voltage sources as semi-holonomic constraints. We find that the dynamics of the system corresponds to that of a planar rotor with an oscillating pivot. We show that the system exhibits a rich dynamical behaviour with chaotic properties and we present a topological classification of the cyclic solutions, providing insight into the fractal nature of the dynamical attractors.
Compressive sensing–based optical two-frequency continuous wave time-of-flight ranging system
Authors: Thanh Vu Tung , Tran Thuc Van , Pham Quang Duc 
Published: May 2024

Abstract
A time-of-flight–based ranging system constructed using an intensity-modulated light source and photodetectors (PDs) is proposed. In the proposed system, the carrier wave, which comprises two cosine waves with different frequencies in the megahertz range, is reconstructed from a few samples obtained using PDs with kilohertz sampling rates using the compressive sensing technique. This allows the system to measure distances with very high accuracy and extends the measurement range while maintaining the accuracy of an existing system that uses a single-frequency carrier.
Electronic, elastic, and thermodynamic properties of complex hydrides XAlSiH (X = Sr, Ca, and Ba) intended for hydrogen storage: an ab-initio study
Authors: Ammi H , Charifi Z , Baaziz H , Ghellab T , Bouhdjer L , Adalla S 
Published: May 2024

Abstract
The mechanical and thermodynamic properties of polyanionic hydrides XAlSiH (X = Sr, Ca, and Ba) were evaluated using density functional theory (DFT). The thermal parameters of XAlSiH hydrides, such as the Grüneisen parameter γ, heat capacity, and thermal expansion coefficient, were computed for the first time. The quasi-harmonic Debye model was used to determine these parameters over a range of pressures (0–40 GPa) and temperatures (0–1000 K). The gravimetric hydrogen storage capacities for BaAlSiH, SrAlSiH, and CaAlSiH were found to be 0.52%, 0.71%, and 1.05%, respectively. The hydrogen desorption temperatures for these compounds were also simulated at 748.90 K, 311.57 K, and 685.40 K. Furthermore, semiconducting behavior with an indirect bandgap value between 0.2 and 0.7 eV was exhibited by these compounds using the GGA and LDA approximation, and between 0.7 and 1.2 eV using the mBJ-GGA and mBJ-LDA approximation. Accurate elastic constants for single crystals were obtained from the calculated stress–strain relationships. The elastic constants for the XAlSiH compounds were significantly higher than those for other hydrides. The [001] direction was more compressible than the [100] direction in the hexagonal structure of XAlSiH. A lower bulk modulus than metallic hydrides was exhibited by these materials, indicating that XAlSiH compounds (X = Sr, Ca, and Ba) were highly compressible. The melting temperature for CaAlSiH was higher than that for SrAlSiH and BaAlSiH. Consequently, the decomposition temperature for XAlSiH (X = Sr and Ba) at which hydrogen was released from a fuel cell was lower than that for CaAlSiH. The bonding behavior of CaAlSiH was more directional than that of SrAlSiH and BaAlSiH. Brittle materials were XAlSiH (X = Sr, Ca, and Ba). Our PBE calculations yield linear compressibility and orientation-dependent Young’s modulus. Materials composed of hexagonal XAlSiH (where X represents Sr, Ca, or Ba elements) exhibit anisotropy in Young’s modulus but isotropy in bulk modulus.
Scaling solutions as Early Dark Energy resolutions to the Hubble tension
Authors: Copeland Edmund J. , Moss Adam , Sevillano Muñoz Sergio , White Jade M.M. 
Published: May 2024

Abstract
A wide class of scalar field models including Quintessence and K-essence have the
attractive property of tracker regimes, where the energy density stored in the field evolves so as
to mimic that of the dominant background component. During this evolution, for a brief period of
time, there is an increase in the energy density of the field as it spirals in towards its
attractor solution. We show that when the peak of this energy density occurs around the epoch of
equality, we can address a key requirement of early dark energy (EDE), postulated as a solution to
the Hubble tension. In particular we demonstrate how this can occur in a wide class of
Quintessence, axion and K-essence models, before showing that the Quintessence models suffer in
that they generally lead to sound speeds incompatible with the requirements of EDE, whereas the
K-essence and axion models can do a better job of fitting the data.
A self-similar model of galaxy formation and dark halo relaxation
Authors: Velmani Premvijay , Paranjape Aseem 
Published: May 2024

Abstract
We develop a spherical self-similar model for the formation of a galaxy through gas collapsing in an isolated self-gravitating dark matter halo. As is well known, the self-similarity assumption makes the problem eminently tractable by reducing it to a system of ordinary differential equations. We improve upon the existing literature on self-similar collapse in two ways. First, we include the effects of radiative cooling and the formation of a pseudo-disk at the center of collapse, in a parametrised manner. More importantly, we solve for the evolution of gas and dark matter simultaneously and self-consistently using a novel iterative approach. As a result, our model produces shell trajectories of both gas and dark matter that qualitatively agree with the results of full hydrodynamical simulations of self-gravitating systems. We discuss the impact of various ingredients such as the accretion rate, gas equation of state, disk radius and cooling rate amplitude on the evolution of the gas shells, although we leave the inclusion of stellar and black hole activity to future work. The self-consistent evolution of gas and dark matter allows us to study the response (or `quasi-adiabatic relaxation') of the dark matter trajectories to the presence of collapsing gas, an effect that has gained increasing importance recently in the context of precision estimates of small-scale statistics like the matter power spectrum. Our default configuration produces a relaxation relation in qualitative agreement with that seen in cosmological hydrodynamical simulations, and further allows us to easily study the impact of the model ingredients mentioned above. As an initial application, we vary one ingredient at a time and find that the accretion rate and gas equation of state have the largest impact on the relaxation relation, while the cooling amplitude plays only a minor role. Our model thus provides a convenient framework to rapidly explore the coupled nonlinear impact of multiple astrophysical processes on the mass and velocity profiles of dark matter in galactic halos, and consequently on observables such as rotation curves and gravitational lensing signals.
Suppression of matter density growth at scales exceeding the cosmic screening length
Authors: Eingorn M. , Yilmaz E. , Yükselci A.E. , Zhuk A. 
Published: May 2024

Abstract
One of the main objectives of modern cosmology is to explain the origin and evolution of cosmic structures at different scales. The principal force responsible for the formation of such structures is gravity. In a general relativistic framework, we have shown that matter density contrasts do not grow over time at scales exceeding the cosmic screening length, which corresponds to a cosmological scale of the order of two to three gigaparsecs at the present time, at which gravitational interactions exhibit an exponential cut-off. This is a purely relativistic effect.
To demonstrate the suppression of density growth, we have performed N-body simulations in a box with a comoving size of 5.632 Gpc/h and obtained the power spectrum of the mass density contrast. We have shown that it becomes independent of time for scales beyond the screening length as a clear manifestation of the cosmic screening effect.
Star Image Centering with Deep Learning. II. HST/WFPC2 Full Field of View
Authors: Casetti-Dinescu Dana I. , Baena-Gallé Roberto , Girard Terrence M. , Cervantes-Rovira Alejandro , Todeasa Sebastian 
Published: May 2024

Abstract
We present an expanded and improved deep-learning (DL) methodology for determining centers of star images on Hubble Space Telescope/Wide-Field Planetary Camera 2 (WFPC2) exposures. Previously, we demonstrated that our DL model can eliminate the pixel-phase bias otherwise present in these undersampled images; however that analysis was limited to the central portion of each detector. In the current work we introduce the inclusion of global positions to account for the point-spread function (PSF) variation across the entire chip and instrumental magnitudes to account for nonlinear effects such as charge transfer efficiency. The DL model is trained using a unique series of WFPC2 observations of globular cluster 47 Tuc, data sets comprising over 600 dithered exposures taken in each of two filters—F555W and F814W. It is found that the PSF variations across each chip correspond to corrections of the order of ∼100 mpix, while magnitude effects are at a level of ∼10 mpix. Importantly, pixel-phase bias is eliminated with the DL model; whereas, with a classic centering algorithm, the amplitude of this bias can be up to ∼40 mpix. Our improved DL model yields star-image centers with uncertainties of 8–10 mpix across the full field of view of WFPC2.
A generalized presentation of multi-caloric effects based on exterior derivative theory and its applications
*
Authors: Yin Jun 
Published: May 2024

Abstract
The emerging concept of multi-caloric effects, introduced in 2010, entails the application of multiple interplay fields to a thermodynamic system. While multi-caloric effects are the main focus of experimental endeavors, theoretical considerations fall short of providing a thorough understanding. This paper introduces a comprehensive presentation on multi-caloric effects, employing the method and theory of exterior derivative formations. It addresses every aspect of thermodynamic systems, showcasing its applicability to multi-caloric materials (both single-phase and multi-phase materials), and its adaptability to different scenarios (either in single or multiple force fields). The formulation of Maxwell relationships, characterized by their generality and universality, enables a clear prediction in entropy and temperature, facilitating a distinct identification between independent and interdependent contributions from multi-caloric effects. These insights hold significant importance in designing and developing specialized thermodynamic materials, optimizing functional performances and exploring innovative mechanisms.
Experimental evidence for the drift wave nature of the weakly coherent mode in ASDEX Upgrade I-mode plasmas
Authors: Herschel M. , Happel T. , Wendler D. , Griener M. , Kalis J. , Fischer R. , Manz P. , Stroth U. ,   the ASDEX Upgrade Team
Published: May 2024

Abstract
The improved energy confinement mode (I-mode) is a potential candidate for future fusion power plants, as it combines ELM-free operation with good confinement. The unusual edge transport and turbulence in this regime is still not fully understood. This study analyzes the turbulent structure of the weakly coherent mode (WCM) in ASDEX Upgrade. Measurements from Doppler back-scattering and a thermal helium beam diagnostic are used to determine velocities of the background plasma and the WCM over multiple discharges. A phase velocity of the WCM of the order of 2–5 km s−1 in the electron diamagnetic drift direction is found, quantitatively close to a drift wave assuming negligible temperature fluctuations. A good agreement with a previously proposed mechanism behind the I-mode regime is observed. This marks the first experimental verification of a specific understanding of the WCM and the I-mode regime.
Experimental and simulation analysis of Weakly Coherent Modes in I-mode discharges on EAST
Authors: Liu Y.J. , Liu Z.X. , Xia T.Y. , Zhang T. , Liu A.D. , Liu J. , Deng C.C. , Ye K.X. , Geng K.N. , Li G.S. , Long F.F. , Li J.Y. , Li P.C. , Yang K.N. , Zang Q. , Ti A. , Zhao H.L. , Liu H.Q. , Li H. , Xie J.L. , Lan T. , Mao W.Z. , Zhou C. , Ding W.X. , Zhuang G. , Liu W.D. , Li G.Q. , Gao X. 
Published: May 2024

Abstract
This paper reports the recent observation of a weakly coherent mode (WCM) within a conventional reflectometer on EAST and successfully determines its poloidal wavenumber range. During the transition from the L-mode to I-mode, the line-averaged density remains nearly unchanged while a significant change is observed in the electron cyclotron emission (ECE) signals at the boundary. The difference between the signals for the two channels at the edge increased, coinciding with the appearance of the WCM and a simultaneous rise in the boundary electron temperature. Further investigation unveiled the modulating role of edge temperature ring oscillation (ETRO) (Liu et al 2020 Nucl. Fusion
60 126016) on high-frequency density fluctuations. Statistical results unveil an inverse relationship between the centeral frequency of the WCM and q
95. Simulation results provide additional insights, demonstrating that the simulated ‘WCM’ in the density fluctuations aligns with experimental data in terms of center frequency. Additionally, the radial distribution of the simulated ‘WCM’ closely corresponds to regions with the strongest electron temperature gradients. Finally, through a cross-correlation analysis of the simulated fluctuations, the following phase relationship for the wavenumber range of ‘WCM’ was observed:

α

T
~

e

>

α

n
~

i

∼

α

ϕ
~

>

α

T
~

i

.
In-beam test results of an RPC-based module for position-sensitive neutron detectors with timing readout
Authors: Canezin G. , Margato L.M.S. , Morozov A. , Blanco A. , Saraiva J. , Lopes L. , Fonte P. , Lai Chung Chuan , Svensson Per-Olof , Markaj G. , Piegsa Florian M. 
Published: May 2024

Abstract
Recently we have proposed a new concept of a thermal neutron
detector based on resistive plate chambers and 10B4C solid
neutron converters, enabling to readout with high resolution in both
the 3D position of neutron capture and the neutron time of flight
(ToF). In this paper, we report the results of the first beam tests
conducted with a new neutron RPC detection module, coupled to the
position readout units of a new design. The main focus is on the
measurements of the neutron ToF and identification of the converter
layer where the neutron is captured, giving the position along the
beam direction.
Evaluating the effects of different tree species on enhancing outdoor thermal comfort in a post-industrial landscape
Authors: Vatani Mehran , Kiani Kamyab , Mahdavinejad Mohammadjavad , Georgescu Matei 
Published: May 2024

Abstract
A frequently emphasized strategy to reduce the burden of heat in cities across the world is the implementation of street trees. Here, we examine the effects of deciduous and coniferous tree deployment on meteorological variables and pedestrian thermal comfort through analysis of the new dynamic thermal comfort (dPET) index, using the latest version of the computational fluid dynamics model ENVI-met. We performed on site observational measurements of air temperature (Ta), relative humidity (Rh), wind speed (Ws), and mean radiant temperature (MRT) at five different locations on the hottest day of summer 2023, in a post-industrial urban landscape located in Tehran, Iran. Observations were used to evaluate ENVI-met simulation performance and served as a baseline against which sensitivity experiments—based on a minimum (35%) and maximum (75%) intervention scenario for deciduous and coniferous trees—were compared against. Our analysis indicates that 35% and 75% deployment reduced Ta by 1.2 °C and 4.2 °C, respectively, for deciduous tree species, compared to a 0.9 °C and 3.1 °C reduction for coniferous species, during the hottest day of summer 2023. The maximum deployment scenario decreased MRT by approximately 60 °C and 43 °C for deciduous and coniferous tree deployment, respectively. The maximum tree deployment scenario decreased dPET by nearly 16 °C and 14 °C for deciduous and coniferous trees, respectively, during the time of day that diurnal heating is maximized. Our findings highlight micrometeorological and personalized thermal comfort effects associated with variable tree species type and extent through examination of a pedestrian’s ambulatory experience across diverse urban microclimates in a region of the world that is particularly understudied.