bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spectral and timing analysis of NGC 7314
Authors: Kalli Siham , Zoghbi Abderahmen , Costantini Elisa 
Published: May 2024

Abstract
The analysis of X rays observations from the active galactic nuclei is a good tool to study the properties of the supermassive black hole, the physics of the accretion disk and the corona, and to model their geometries. We present a detailed spectral and timing analysis of the Seyfert galaxy NGC 7314, we used all available public XMM-Newton and NuSTAR observations from 2001 to 2016. In order to improve the spectral modeling, we used both relativistic and non relativistic reflection models. We confirmed the presence of narrow and Broad Iron lines and we obtained constraints for other spectral proprieties. For the timing analysis, we first studied the behaviour of the power density spectrum, then we studied the time delays between the direct X rays emission and the reflected emission from the accretion disk, we measure reverberation in at least one observation, but we do not see it in others, suggesting it may be a transient phenomenon.
Relativistic atomic structure calculations of Li-like ions used for plasma diagnostic studies
Authors: Singh Gajendra , Singh A K , Chowdhuri M B , Nandi T 
Published: May 2024

Abstract
We have carried out atomic structure calculations using systematically enlarged multiconfiguration Dirac-Fock wavefunctions of Li-like ions of the most prominent plasma impurities (Ar, Ti, Fe, Ni, Kr and W) found in presently working tokamaks. Relativistic Breit interaction and quantum electrodynamic (QED) corrections such as vacuum polarization and self-energy corrections are also included in the calculations prior to the evaluation of low lying energy levels, transition probabilities, oscillator strengths and line strengths. Selective radiative data for electric dipole and magnetic quadrupole transitions are also reported. Special emphasis is given in the computations of fundamental quantities such as oscillator strengths as they are widely used in atomic data and analysis structure (ADAS) databases to evaluate quantities such as effective collision strengths. Present computed values are compared with existing available results on NIST database and few similar earlier computations and a good agreement has been found. We believe that the detailed atomic data with the relativistic and QED corrections will assist in spectroscopic studies such as accurate line identification and plasma modelling work in tokamak plasma, laser induced breakdown spectroscopy (LIBS), highly charged ions clocks and astrophysical observations.
Pressure effects on the structural, electronic, elastic, optical, and vibrational properties of YMg intermetallic compounds: a first-principles study
Authors: Ciftci Yasemin O , Çatıkkaş Berna 
Published: May 2024

Abstract
The properties of YMg in B2 structure have been comprehensively analysed using the first-principles plane-wave pseudopotential method. Specifically, the structural, electronic, elastic, vibrational, and optical properties were investigated using the generalized gradient approximation (GGA) method in the context of density functional theory. The Vienna ab initio simulation package (VASP) was utilized for these calculations. The computed lattice parameter (3.803 Å) and bulk modulus (41.33 GPa) are consistent with the earlier data on ambient pressure. The electronic band structure and energy-dependent density of states reveal the metallic nature of the titled compounds. The Born stability requirements confirmed the mechanical stability. The analysis of Pugh’s and Poisson’s ratios and Cauchy’s pressure reveals that YMg is ductile under the pressures in consideration. According to several anisotropy indices, the compound is noticeably anisotropic both in ambient and under pressure. Our investigation includes an analysis of several fundamental mechanical parameters of the material, including the bulk modulus, the pressure derivative of the Zener anisotropy factor, Poisson’s ratio, isotropic shear modulus and Young’s modulus with a particular focus on their dependence on pressure. We have determined that the elastic constants obtained remain mechanically stable, satisfying the Born Stability conditions even at high pressures of up to 60 GPa. To explore the dynamic stability of YMg, we analysed the material’s phonon dispersion curves. The examined compound displays stability under dynamic conditions from 0 GPa to 30 GPa, as evidenced by its positive vibration frequencies. However, this stability is not sustained under higher pressure, as the compound becomes unstable after 30 GPa to 70 GPa. The electronic band structure and density of states diagrams demonstrate YMg’s metallic properties. At atmospheric pressure (0 GPa), the total density of states (TDOS) near the Fermi level is approximately 1.63 states/eV, with pressure application reducing DOS. The dielectric function, refractive index, and energy loss spectra are examined within the 0–20 eV energy range. YMg exhibits its highest absorption between 4 and 11 eV. The peak optical conductivity is observed around 0.78 eV (equivalent to 1589.5409 nm), while the most significant energy loss occurs at 11.90 eV, roughly corresponding to 2.8 Hz in the ultraviolet spectrum. Moreover, we extensively analyzed the material’s phonon thermodynamic and optical properties, providing insights into its behavior under various conditions. The outcomes acquired at zero pressure are generally coherent with the current theoretical values.
First-principles study on the structural, elastic, electronic, optical and thermophysical properties of NaNO3 and K-doped NaNO3
Authors: Mehra Vidya , Ahmad Tahir , Agrawal Anju , Jha P K , Nautiyal Arvind , Semalty P D 
Published: May 2024

Abstract
The current work illustrates the optical, thermophysical, electronic, elastic, and structural characteristics of pure and K-doped NaNO3 obtained using DFT calculations. Electronic characteristics such as band structure, projected and total density of states of pure and doped NaNO3 are analyzed where the calculated band gaps for pure and K-doped NaNO3 were discovered to be 3.05 eV and 2.90 eV, respectively. The Berry–phase calculations carried out on both systems showed the existence of ferroelectric polarization, where an enhanced spontaneous polarization value of 36 μC/cm2 for K-doped NaNO3, as compared to 20 μC/cm2 for intrinsic NaNO3 is obtained. The thermophysical properties such as bulk modulus (B0), Debye temperature (θ
D), and specific heat capacity (Cv) were calculated over a wide temperature range from 0 K to 800 K. The linear optical properties namely the dielectric constant, refractive index, electron energy loss function, absorption and extinction coefficient are calculated in wide energy range from 0 to 30 eV and discussed in detail.
A feature enhanced EEG compression model using asymmetric encoding–decoding network
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Authors: Wang Xiangcun , Zhang Jiacai , Wu Xia 
Published: May 2024

Abstract

Objective. Recently, the demand for wearable devices using electroencephalography (EEG) has increased rapidly in many fields. Due to its volume and computation constraints, wearable devices usually compress and transmit EEG to external devices for analysis. However, current EEG compression algorithms are not tailor-made for wearable devices with limited computing and storage. Firstly, the huge amount of parameters makes it difficult to apply in wearable devices; secondly, it is tricky to learn EEG signals’ distribution law due to the low signal-to-noise ratio, which leads to excessive reconstruction error and suboptimal compression performance. Approach. Here, a feature enhanced asymmetric encoding–decoding network is proposed. EEG is encoded with a lightweight model, and subsequently decoded with a multi-level feature fusion network by extracting the encoded features deeply and reconstructing the signal through a two-branch structure. Main results. On public EEG datasets, motor imagery and event-related potentials, experimental results show that the proposed method has achieved the state of the art compression performance. In addition, the neural representation analysis and the classification performance of the reconstructed EEG signals also show that our method tends to retain more task-related information as the compression ratio increases and retains reliable discriminative information after EEG compression. Significance. This paper tailors an asymmetric EEG compression method for wearable devices that achieves state-of-the-art compression performance in a lightweight manner, paving the way for the application of EEG-based wearable devices.
Uniqueness of the Eigenvalue Inverse Problem for a Class of X-type Matrices with Linear Relations
Authors: Yu Tong , Li Zhibin , Wang Lidong 
Published: May 2024

Abstract
Constraining a matrix by adding additional conditions to determine the matrix if given eigenpairs is called the eigenvalue inverse problem for matrices. The eigenvalue inverse problem of a matrix can be based on a given combination of different eigenvectors and real numbers to inverse a matrix method, and the method of inversion varies for different types of matrices. In this paper, we investigate the eigenvalue inverse problem for a class of X-type matrices characterized by linear relations, Invert the matrix based on its characteristics, determine eigenvalues and eigenvectors, and finally, prove that the solution of the problem exists and is unique, derive a series of expressions and recursive formulas, and we also check the algorithm’s accuracy correctness by giving different instances.
An Iterative Algorithm for Maximal and Minimal Solutions of a Class Matrix Equations
Authors: Li Lin , Su Dongqing , Zhao Xuejun 
Published: May 2024

Abstract
In the paper, the peak solutions of a class equation is studied, the peak solutions are the maximal and minimal solutions. There is an iterative algorithm given for the solutions of the class equation. First, the existence of the peak solutions of the class equations is obtained. Second, when the peak solutions exist, an iterative algorithm is established to converge to the peak solutions of the class equation. By an upper bound and a lower bound of the solutions of the equation solution as the initial matrix, the iterative algorithm of the paper converges to the peak solutions of the class equation. The convergence problem of the algorithm is proved by the mathematical induction in the paper. The above results are verified by the examples.
Optimal Transport Approaches for Cloud Fusion in 3D Reconstruction
Authors: Chen Duo 
Published: May 2024

Abstract
Cloud fusion plays a crucial role in achieving accurate 3D models. This paper introduces two optimal transport-based approaches, Gaussian Fusion and Cyclical Fusion, to showcase the effectiveness of optimal transport in establishing dense correspondence among incoming 3D point clouds. These approaches encompass several important components. Firstly, the fusion correspondences are derived from the optimal transport problem. The core principle of Gaussian Fusion and Cyclical Fusion involves manipulating points along geodesic curves to effectively leverage significant local geometric information. Secondly, this paper explores the fundamental concepts underlying Gaussian Fusion (displacement interpolation) and Cyclical Fusion (cyclical monotonicity), which greatly enhance the accuracy and completeness of the reconstruction process. And provides evidence for the uniqueness of displacement interpolation as geodesics on L2-Wasserstein space and the rationality of cyclical monotonicity in this context. Finally, the proposed approaches excel in capturing intricate surface details, particularly on small objects, when compared to the original fusion scheme which often introduces severe artifacts.
Rician Noise Removal in Low-noise Condition via a Deep Unfolding Network
Authors: Fei Tiancheng , Feng Xiangchu 
Published: May 2024

Abstract
Nuclear magnetic resonance (NMR) signals as the key role of research on denoising, are mainly influenced by Rician noise. Restoring clean Rician medical images from signal-related Rician noise is a challenging task with great practical significance. In this paper, an energy function based on MAP estimation is proposed, mainly for conditions of low noise, where the noise distribution is approximately Gaussian. Then the mathematical model is embedded into the network structure to realize the knot of knowledge-driven and network learning. The experiment shows that the proposed model only uses simple and lightweight network modules and a small amount of training data, which has a better denoising effect and has achieved satisfactory results under the two evaluation indexes.
Research on Expansion Coefficient Based on Water Temperature Density Regression Function
Authors: Wei Fengjun , Liu Chunhua , Zhang Fengxia , Guo Rendong , Hu Jilei , Che Chuanxun 
Published: May 2024

Abstract
Based on the regression function of water temperature and water density, two expressions of the thermal expansion coefficient function of water are obtained by integrating and differentiating the function. Compared with the measured data, the theoretical formula of the integral method is in good agreement with the measured accumulated thermal expansion coefficient of water obtained by the cumulative step size. The theoretical formula of the differential method is in good agreement with the measured cumulative thermal expansion coefficient of water obtained by equal step size and variable step size. Therefore, no matter the theoretical formula of the integral method or differential method, it can be used for the thermal expansion coefficient of water with cumulative step size or with finite equal step size or finite variable step size. The theoretical formula of the thermal expansion coefficient of water with integral method and differential method is of high precision and easy to use.
Numerical Simulation of Airflow Velocity and Temperature Distribution in an Aircraft Cabin
Authors: Tan Jingqi , Chen Lijun , Wang Lei , Guo Wenjun , Pan Jun , Wang Xiaoping 
Published: May 2024

Abstract
In this work, a computational fluid dynamics (CFD) model is established to calculate the airflow distribution in the cabin of a single-channel Boeing 737-800 airplane. The RNG k-ε model, considering the calculation of turbulence kinetic energy and its rate of dissipation, is adopted to solve turbulence problems in physical field simulation. The proposed three-dimensional model is able to consider the particular physical factors and spatial structures, which can simulate the detailed distributions of complex physical fields, compared with the one-dimensional lumped parameter model. The velocity and temperature fields under different air supply velocities are then numerically investigated. The calculation results show that when the air velocity at the top air supply inlet is 1.4 m/s, the velocity and temperature distribution inside the cabin can both meet the comfort requirements of humans in the airworthiness standards. The results from this work can help to design an aircraft environmental control system.
Effect of Chute on Gas Flow and Temperature of the Top of Blast Furnace
Authors: Cheng Xiaoman , Cheng Shusen 
Published: May 2024

Abstract
The top gas temperature is an apparent indicator of the distribution state of gas flow, and it is an important parameter to judge the furnace condition. It is related to the top equipment in addition to the charge characteristics and bottom-up generation and distribution. Therefore, the fluid-solid heat transfer model from burden surface -chute-rising ducts is established in this paper. The finite element method is used to calculate the flow and heat transfer of the gas at the top of the blast furnace, and the influence of the chute on the top gas temperature is analyzed. The accuracy of the model is verified by the actual blast furnace top temperature. The results show that the chute has a guiding effect on the gas flow. As the chute rotates, the top gas temperature fluctuates. This research is helpful for actual blast furnace operators to understand the top temperature and make the condition judgment more accurate.
Experimental evaluation of a vapour compression refrigeration system using a nano-oil mixture of TiO2, Al2O3, and SiO2
Authors: Madyira D.M , Babarinde T.O 
Published: May 2024

Abstract
Nanolubricants were used to improve the performance of refrigeration systems in a household refrigerator. In this study, a pure lubricant is used as the base compressor lubricant, and nanoparticles of TiO2, Al2O3, and SiO2 at 0.4g/L concentrations are used as nanolubricants in 50g isobutane (R600a) refrigerants. Power consumption was investigated alongside the COP. TiO2 nanolubricant has the highest COP of 2.8 and the lowest power consumption of 11.3% when compared to based lubricant. However, in terms of power consumption, SiO2 and Al2O3-nanolubricant outperformed the based lubricant by 4.5% and 7.7%, respectively. This suggests that a nanolubricant could be used in a refrigeration system to replace a based lubricant with R600a refrigerant.
The role of Palm Fronds Charcoal Waste Particles On Mechanical, Thermal, and Acoustic Insulation Properties of Epoxy Composite
Authors: Ahmed Zainab W , Kadim Adil I 
Published: May 2024

Abstract
The main objectives of the current study are to improve the mechanical, thermal, physical and sound insulation properties of an epoxy composite, in addition to reducing environmental pollution resulting from the burning of palm kernel waste, which results from annual periodic cleaning of the palms trees, which have been disposed of by burning it. Charcoal Waste Particles of Palm Fronds Base have been used for epoxy matrix as a naturalistic reinforcement particulate material, risk-free, and non-toxic to enhance its features. The charcoal waste particles have been used in weight rates of 0, 2.5, 5, 7.5, and 10%. As stated by the results, the reinforcement process by charcoal waste particles increased the tensile strength value from 8.78 MPa to 13.64 MPa, with a 55%, and increased the elastic modulus value from 0.67MPa to 3.63MPa, with a rate 437%. Moreover, additionally, increased the bending strength from 0.1MPa to 0.64MPa, with a 540%, the hardness value increased from 58.87 to 74 (Shore D No) with a rate 26%, as well as the wear rate has been decreased. Thermal conductivity has dropped by 30% from the pure sample’s value of 0.15W/m. °C to 0.11W/m. °C. Concerning the Acoustic insulation’s, the results demonstrate that the specimens decreased the transferred acoustic energy levels from 103.3 to 95.2dB with rate 8%, with regard to the density of the prepared specimens it has been decreased from 1.55g/cm3 to 1.35g/cm3 and the results show that the liquid absorption rates have been decreased for all composite specimens.
Enhancement of swimming pool water quality by nanotechnology
Authors: Yousef Farman Halla , Hasan Al-Anbari Riyadh , Haider Adawiya J. 
Published: May 2024

AbstractBecause of the hazards associated with the use of chlorine in pool water treatment, a commercial polysulfone ultrafiltration membrane was utilized. These membranes were coated with varying concentrations of Ag-ZnO nanomaterial (0.05, 0.1, 0.2) and employed in a filter system designed to imitate the swimming pool water treatment process. The experiment lasted three months (April, May, and June) and was carried out for three days each month. The impact of nano-Ag-Zno on the UF nanocomposite membrane was investigated. To analyze the mechanical properties of the membranes, scanning electron microscopy (SEM), porosity, and contact angle were used. The findings reveal that treating the substrates with Ag-ZnO enhanced their hydrophilicity and porosity. Acommercial polysulfone membranes were coated with amixture of Ag-ZnO nanoparticles using the spray pyrolysis technique. The impact of nano-Ag-ZnO on the UF nanocomposite membrane was investigated. To analyze the mechanical properties of the membranes, SEM and contact angle were used. According to the findings, applying Ag-Zno in different concentration to the substrates boosted their hydrophilicity and porosity and aconcentration (2%) could achieve the goal of the research, which is to reduce the use of chlorine disinfection by eliminating Escherichia Coli bacteria, which considered acommon species in swimming pool water.
B-diketon Derived Ligands Metal Complexes, Synthesize, Characterization, and Bioactivity Studies
Authors: Rasheed Ali Fatima , Hassan Hasan A. 
Published: May 2024

Abstract
The precursor in our study 2, 2’- ((1E,1’E) - (4,4’- diamino - 5, 5’- dimethyl - [1,1’-biphenyl]-3, 3’-diyl) bis(diazene-2,1-diyl) diphenol (W1) or (W2) 3,3’-dimethyl-5,5’-bis((E)-pyridin-3-yldiazenyl)-[1,1’-biphenyl]-4,4’-diamine were obtained from reaction of diazonium salt with tolidin. The both precursors used for synthesis of the ligands [H4L1] and [H2L2] by reaction with di benzyl methan to produce the ligands [H4L1]2,2’-((1E,1’E)-(4,4’-bis((3-hydroxy-1,3-diphenylpropylidene)amino)-5,5’-dimethyl-[1,1’-biphenyl]-3,3’-diyl)bis(diazene-2,1-diyl))diphenoland [H2L2] 3,3’-((3,3’-dimethyl-5,5’-bis((E)-pyridin-3-yldiazenyl)-[1,1’-biphenyl]-4,4’-diyl)bis(azaneylylidene))bis(1,3-diphenylpropan-1-ol). Elemental microanalysis, 1H and 13C-NMR, FT-IR, U.V, mass spectroscopies were used to describe the structure of the ligands. In this research we also reported the complexes synthesis via reaction of of [NiII, MnII, CoII, CdII, CuII] chloride salts with ligands, using KOH as a base and ethanol as a solvent, under reflux. Complexes were characterized by atomic absorption, (FT-I.R, U.V-Vis, 1H and 13C-NMR and mass) spectroscopies along with conductivity, magnetic susceptibility and melting point measurements. The presence of crystallized water molecule insured by thermal analysis in some complexes structure. Finally, the synthesized ligands and complexes biological activity studied against selected organisms.
The Simulation of Double Head Streamer Discharge in a 0.5 cm Air Gap
Authors: Abdulameer Maha. F. , Khalaf Thamir H. 
Published: May 2024

Abstract
The production and evolution of the double-head streamer discharge in air, as well as the characteristics of positive & negative streamers, were described in this work using a computer simulation method. Streamer discharge in a 0.5 cm air’ gap has been modeled and simulated by the fluid model. Under DC voltage, the model was tested using an axisymmetric plane-to-plane electrode layout in two dimensions. The model was implemented in commercial computation software COMSOL Multiphysics version 6.0 based on finite element method (FEM), in which a time-dependent solver was used. Results indicated that negative streamers travel more quickly than positive ones’, the charged particles (electrons and ions) density have the range of (1013 – 1014) cm−3 in both positive & negative streamer and the breakdown time for the gap (0.5cm) occurs in several nanoseconds.