bluuebunny/crossref_metadata_2025_split huggingface dataset:
Machine learning for observational cosmology
Authors: Moriwaki Kana , Nishimichi Takahiro , Yoshida Naoki 
Published: May 2023

Abstract
An array of large observational programs using ground-based and space-borne telescopes is planned in the next decade. The forthcoming wide-field sky surveys are expected to deliver a sheer volume of data exceeding an exabyte. Processing the large amount of multiplex astronomical data is technically challenging, and fully automated technologies based on machine learning (ML) and artificial intelligence are urgently needed. Maximizing scientific returns from the big data requires community-wide efforts. We summarize recent progress in ML applications in observational cosmology. We also address crucial issues in high-performance computing that are needed for the data processing and statistical analysis.
Undoped vertical dual-bilayer TFET with a super-steep sub-threshold swing: proposal and performance comparative analysis
Authors: Anam Aadil , Amin S Intekhab , Prasad Dinesh , Kumar Naveen , Anand Sunny 
Published: May 2023

Abstract
In this paper, the undoped vertical dual-bilayer tunnel field effect transistor (UV-DBL-TFET) at a low operating voltage (0.5 V) is introduced, and its DC and RF performance parameters are compared with those of the conventional charge plasma-based symmetrical gate electron–hole bilayer TFET (CP-SG-EHBTFET). The charge plasma technique is used in the proposed device to induce the source/drain and electron–hole dual-bilayer channel dopants. Due to the dopingless architecture of the proposed UV-DBL-TFET, its fabrication is simple and efficient, and it does not require an expensive thermal annealing process. Due to its dopingless architecture, the proposed UV-DBL-TFET is immune against random dopant fluctuations. In the study, the quantum confinement effects in the TCAD simulation have been successfully modelled using the Schrodinger approach and the density gradient model. Compared to the conventional CP-SG-EHBTFET, the proposed UV-DBL-TFET has a dual EHB channel, triggers dual line tunnelling, and doubles the band-to-band tunnelling rate and the ON current. Compared to the I
ON of 47.33 μA μm−1 and AVSS of 13.53 of the conventional CP-SG-EHBTFET, the proposed UV-DBL-TFET has almost double the ON current of 93.46 μA μm−1 with a reduced AVSS of 12.3 mV dec−1. The proposed UV-DBL-TFET also gives improved RF/analog performance. Compared to the transconductance (g
m) of 0.337 mS, the cut-off frequency (f
T) of 65.17 GHz, and the gain-bandwidth-product (GBW) of 16.5 GHz of the conventional CP-SG-EHBTFET, the proposed UV-DBL-TFET has a g
m of 0.665 mS, a f
T of 129.0 GHz, and an GBW of 32.6 GHz, an almost doubled improvement. Furthermore, the proposed UV-DBL-TFET-based CMOS inverter has also been comprehensively studied, and perfect complementary inverter action has been obtained, suggesting great potential for future low-power applications.
Quantum information entropy of a particle trapped by the Aharonov–Bohm-type effect
Authors: Lima F C E , Moreira A R P , Almeida C A S , Edet C O , Ali N 
Published: May 2023

Abstract
In this research article, we use the Shannon’s formalism to investigate the quantum information entropy of a particle trapped by the Aharonov–Bohm-type field. For quantum information study, it is necessary to investigate the eigenstates of the quantum system, i.e. the wave functions and energies of the quantum states. We assumed that the particle is in principle, confined in a cylindrical box in the presence of Aharonov–Bohm-type effect due to dislocation defect. Analysis of the quantum information entropy, reveals that the dislocation influences the eigenstates and, consequently, the quantum information of the system.
Theoretical study on the thermal transport and its tunability of a-plane trilayer GaN
Authors: Xu Yaxin , Sun Guoqing , Wan Zijing , Xu Dongwei , Luo Xiaobing 
Published: May 2023

Abstract
Two-dimensional (2D) a-plane gallium nitride, a non-layered 2D material, has promising applications in photoelectric nanodevices due to its direct band bandgap. Herein, employing molecular dynamics simulations, we studied the thermal transport properties of a-plane trilayer GaN, and the temperature, together with strain modulation on the thermal conductivity of the system. The a-plane trilayer GaN shows anisotropic thermal conductivity with 70.22 Wm−1K−1 and 41.81 Wm−1K−1 along zigzag- and armchair- directions respectively at room temperature when extrapolated to infinite size. In addition, the thermal conductivity of trilayer GaN exhibits decreasing trend in response to the increase of temperature. The thermal conductivity decreases monotonically with the increased compressive uniaxial and biaxial strain, while it shows an up-then-down trend under tensile strain. The tunability of thermal conductivity under biaxial strain is much larger than that of uniaxial strain. The phonon density of states is further investigated to understand the behavior of thermal conductivity. The tunability of the system thermal conductivity will expand its applications in thermal management and nanodevices.
Thermodynamics of a quantum ring modified by Lorentz violation
Authors: Araújo Filho A A , Hassanabadi H , Reis J A A S , Lisboa-Santos L 
Published: May 2023

Abstract
In this work, we investigate the consequences of Lorentz-violating terms in the thermodynamic properties of a 1-dimensional quantum ring. In particular, we use the ensemble theory to obtain our results of interest. The thermodynamic functions as well as the spin currents are calculated as a function of the temperature. We observe that parameter ξ, which triggers the Lorentz symmetry breaking, plays a major role in low temperature regime. Finally, depending on the configuration of the system, electrons can rotate in two different directions: clockwise and counterclockwise.
Emission spectrum for a cascade-type three-level atom driven by optical field in photon added coherent state of PHO
Authors: Al-Ghamdi M S , Abdel-Khalek Sayed , Berrada Kamal , Al-Sahafi S D 
Published: May 2023

Abstract
A treatment of the interaction of a multi-photon cascade-type three-level atom in a cavity with a single-mode field initially in the photon added coherent states (PA-CSs) of pseudo-harmonic oscillator (PHO) is presented in this paper. The wavefunction corresponding to the system under consideration and the emission spectrum (ES) are obtained. It is shown that the properties of the ES are affected by the PA-CS of PHO parameters. The influence of the number of added photons to the CS of PHO on the dynamical behavior of the ES is investigated. The results showed that the behavior of the ES is strongly changed according to the CS of PHO parameters and its number of added photons. Symmetric peaks are generated around the vertical axis with increasing influence of some values of the initial field state parameters.
Hierarchy of double-time correlations
Authors: Queisser Friedemann , Schützhold Ralf 
Published: May 2023

Abstract
The hierarchy of correlations is an approximation scheme which permits the study of non-equilibrium phenomena in strongly interacting quantum many-body systems on lattices in higher dimensions (with the underlying idea being somewhat similar to dynamical mean-field theory). So far, this method was restricted to equal-time correlators such as

⟨

A
ˆ

μ

(
t
)

B
ˆ

ν

(
t
)
⟩

. Using the method of complete induction, we generalize this method to double-time correlators such as

⟨

A
ˆ

μ

(
t
)

B
ˆ

ν

(

t

′

)
⟩

. The hierarchical decoupling scheme permits the evaluation of correlation functions in thermal equilibrium as well as in non-equilibrium settings. As an application, we study the equilibrium dynamics of correlation functions and the related light-cone structure of the bosonic Hubbard model in the Mott insulator phase. Furthermore we address the light-cone structure when the system is quenched.
Improved Deep Reinforcement Learning Decision for Integrated Control of Distributed Drive Electric Vehicle Dynamics
Authors: Huang Wenjun , Huang Kaiqi , Huang Maoyun 
Published: May 2023

Abstract
To solve the problem of nonlinear coupling with longitudinal and lateral tire forces in the integrated control of distributed driving electric vehicles, an improved SAC reinforcement learning algorithm is proposed to coordinate the control method of active front steering (AFS) and torque distribution. The coordinated control adopts a layered structure, and the upper layer adopts the LQR controller to determine the additional front wheel rotation angle and yaw moment required for stability control. The three-level reward function is designed with the goal of vehicle stability and state tracking and is determined by the reinforcement learning algorithm. For the weight factors of the two optimization objectives, the SAC reinforcement learning algorithm is used to coordinate the decision-making of the active front wheel steering and the additional yaw moment; the lower controller uses the comprehensive utilization rate of the tire as the objective function to perform the optimal torque distribution. A co-simulation platform is established in MATLAB/Simulink and CarSim software. The results show that compared with AFS control, SAC coordinated control can not only ensure the stability of the vehicle and achieve accurate tracking of the reference state but also effectively reduces the comprehensive utilization rate of tires and the effectiveness of coordinated control.
Modification of Carbon Black by Laser Irradiation
Authors: Milenov T , Dimov D , Kostadinov I , Avdeev G , Russev S , Genkov K , Trifonov D , Zyapkov A , Ivanov K , Kolev S , Valcheva E 
Published: May 2023

Abstract
The effect of modification of Cabot Corporation SPHERON 5000 carbon black suspended in bi-distilled water by laser irradiation (CuBr2 laser with fundamental wavelength of λ = 511nm and 2 kHz repetition rate) has been studied. The carbon black suspensions were prepared by mixing 0.10 g carbon black previously treated with acetone in 100 ml bi-distilled water. Different laser beam fluencies and different irradiation times were used in order to optimize the modification process. The modified suspensions were decanted after sedimentation and dried. The powder fractions obtained were studied by scanning electron microscopy, X-ray diffraction and Raman spectroscopy.
Precise material microprocessing by high-power diffraction limited laser radiation in middle infrared spectral range
Authors: Kostadinov I K , Temelkov K A , Karatodorov S I , Popova L T , Slaveeva S I 
Published: May 2023

Abstract
Diffraction-limited laser radiation with a record-high total average output power exceeding 14 W is obtained in the middle infrared spectral region through a new improved master oscillator – power amplifier system based on the strontium vapor laser. Precise microprocessing of optical grade fused quartz, sapphire, stainless steel, hard biological tissues, and polymers is also accomplished. Using a parabolic mirror for the laser beam focusing, spherical aberrations are overcome and a crater diameter and a channel width of the order of the laser wavelength are achieved.
Some Initial Results on Modification of aC:H Films by Pulsed Laser Irradiation
Authors: Milenov T , Karaivanova D , Dikovska A , Kirilov K , Valcheva E 
Published: May 2023

Abstract
It has recently been shown both theoretically and experimentally that a significant modification of the aC:H films is possible using UV irradiation even with a very low irradiation fluence. Some initial results on the modification of aC:H films with thickness of about 40 nm with UV laser irradiation are presented here. The fourth harmonic (λ = 266 nm) of a Nd:YAG laser system (the fundamental wavelength λ = 1064 nm) was used in our experiments. The modified areas of the aC:H films were characterized by optical microscopy, Raman spectroscopy as well as by atomic force microscopy (AFM). A significant modification of aC:H films under certain conditions (laser irradiation fluence and modification modes) to multi-layer graphene accompanied by ablation of a part of the film was established. It was also found that similar aC:H films deposited on 330 nm SiO2/Si substrates did not undergo significant modification under these conditions.
Coherent magneto-optical resonances on the potassium D2 line in Hanle configuration for magnetometry applications
Authors: Tsvetkov S , Andreeva C , Gateva S 
Published: May 2023

Abstract
The coherent magneto-optical resonances on the potassium D2 line are investigated from the point of view of magnetometry applications. The measurements are performed in Hanle configuration with potassium excited by circularly polarized laser beam in cell with dimensions 8 mm and buffer gas 30 Torr Ne. The parameters of the resonances registered in fluorescence and transmission are compared. The capability of the laser system to work with magnetically unshielded cell is demonstrated. The registration of bright and dark magneto-optical resonances detected in fluorescence by controlling the optical thickness of potassium vapor is discussed. The influence of the laser power and transverse magnetic field are considered. The experimental results show the potential of the system for magnetic field sensing and calibration.
Effective application of suitable single pulse of Nd:doped lasers for cleaning of initial carious lesions of human teeth. Experimental study
Authors: Uzunov T , Deneva M , Kazakov V , Uzunova P , Kaimakanova N , Nenchev M 
Published: May 2023

Abstract
We show via detailed experimental investigations that the single pulse from Nd:YAG and Nd:Glass lasers (wavelength 1.06 μm, free lasing operation) are suitable for efficient cleaning initial carious lesions (1 - 3 mm in diameter) on tooth enamel. The cleaning is in combination with tooth preparation for final healing procedures – formation of desired hole and antibacterial cleaning. The measured heating of the tooth chamber is in acceptable limits and crack formation is avoided. The investigation includes laser irradiation with single pulses of energy of ~2 to 5 J, energy density of ~50 to 130 J/cm2 and pulse duration of ~500 ns – 2 ms. In further development of the topic, as a second part of this article, we propose algorithm for application of the discussed cleaning.
PDT and PD of Human Glioblastoma with 5-ALA/PpIX and n-GalLuPc
Authors: Zaharieva L , Angelov I , Genova Ts , Kyurkchiev D , Tumangelova-Yuzeir K , Ivanova-Todorova E , Mantareva V , Karazapryanov P , Minkin K , Avramov L , Borisova E 
Published: May 2023

Abstract
Glioblastoma (GBM) is the most common and severe type of brain tumor. Surgery and subsequent radiotherapy and chemotherapy do not lead to sufficient results in the treatment of this type of malignancy, mostly due to its specific morphology. Only about 6% of the patients of advanced age survive 5 years after being diagnosed with GBM. Therefore, scientists are working on alternative therapies that would lead to more effective and long-term treatment of glioblastoma. Photodynamic therapy (PDT) and photodiagnostics (PD) are such unconventional methods for treating and diagnosing malignant tumors. During our work, more than 20 experiments were carried out with stem cells cultivated from human glioblastoma tumors. We used two types of photosensitizers – delta-aminolevulinic acid (5-ALA) as a precursor of protoporphyrin IX (PpIX) and non-peripherally galactosylated lutetium phthalocyanine (n-GalLuPc). After the irradiation supernatant samples of photosensitizer-treated cell lines were used for evaluation of photosensitizers’ accumulation in the cell lines investigated. The emitting spectra is correlated with the total induced cell death in the treated cells. After considering the overall effectiveness of the two photosensitizers, n-GalLuPc showed higher efficiency. These in vitro results prompted the future investigation of the phthalocyanine for in vivo application in GBM treatments.
Diagnosis of skin lesions through prototype clinical device with diffuse reflectance spectroscopy
Authors: Mircheva V , Borisova E , Genova Ts , Troyanova P , Avramov L , Markovski A 
Published: May 2023

Abstract
Cancerous and precancerous skin conditions occupy one of the leading places in oncology. Early detection of suspects and temporary referrals to a specialist are critical to successful treatment. Numerous optical techniques are used for obtaining a new data from cutaneous neoplasia. Diffuse–reflectance spectroscopy is one of these techniques due to its high sensitivity in detecting subtle tissue alterations. Light scattering events inside the skin tissues change significantly in the development stage of skin lesions. These changes in the tissue scattering properties affect the diffuse reflectance spectrum and provide classification of different skin lesions based on diffuse reflectance measurements. We have investigated diffuse–reflectance spectroscopy for diagnostic of skin lesions and as a result, an optical device for clinical application was developed. The current study shows the obtained results by the prototype device for the reflective ability of pigmented and non-pigmented skin benign, dysplastic, and malignant cutaneous lesions in vivo.
Thermal effects in Nd: YVO4 and Nd: GdVO4 block crystals under diode end-pumped at 914 nm
Authors: Hendaoui N , Boutaka R , Bouadjemine R 
Published: May 2023

Abstract
In this paper, we report a numerical study of the thermal effects within both a-cut crystals Nd: YVO4 (1.5 at.%) and Nd: GdVO4 (1.5 at.%) end-pumped by a diode laser emitting at 914 nm. The temperature, stresses distributions and thermal lensing parameters were calculated by finite element method using LASCAD© software. The obtained results show that the Nd:GdVO4 is the best candidate for high power diode laser end-pumped solid-state lasers because of its lower thermal effects.
Impact of annealing and soft template concentration on optical and sensing properties of wet-deposited SiO2 thin films
Authors: Chorbadzhiyska Y , Georgiev R , Georgieva B , Babeva T 
Published: May 2023

Abstract
The present study demonstrates deposition of porous SiO2 thin films using combination of sol-gel, soft-templating and spin-coating methods. The recipe for Si-sol using TEOS (tetraethylorthosilicate) as a precursor was optimized in order transparent and stable sol to be obtained. Commercially available triblock co-polymer Pluronic 123 was considered as a soft template and its concentration and volume fraction to sol were varied. For achieving the final composition of silica films, different stepwise annealing regimes were implemented where the temperatures and duration of each step were optimized. Optical properties of films were calculated using nonlinear curve fitting of measured reflectance spectra in UV-VIS spectral range. Surface morphology and structure of the films were characterized by Transmission Electron Microscopy (TEM) and Selected Area Electron Diffraction (SAED). The porosity and optical sensing ability of the films were tested by measurement of their reflectance spectra prior to and during exposure to acetone vapors which served as probe molecules. The influence of soft template composition and annealing regimes on SiO2 properties were revealed and application of studied films as sensitive media for opto-chemical sensing was discussed.
Surface modification of Ti6Al4V alloy by continuous electron beam
Authors: Ormanova M , Kotlarski G , Stoyanov B , Valkov S 
Published: May 2023

Abstract
In this work, Ti6Al4V alloy was surface modified by a scanning electron beam. During the modification procedure, the current of the electron beam was 25 mA, the frequency of scanning of the e-beam was 200 Hz, the accelerating voltage was 60 kV, the velocity movement of the sample was 5 mm/s and 10 mm/s. The samples were modified using a continuous electron beam, where the geometry of the beam deflection was in the form of a Lissajous curve. The phase composition of the obtained samples was investigated by X-ray diffraction. The microstructure was studied by optical microscopy. The microhardness was also investigated. The results showed that the treatment process causes the formation of a single-phase structure of α’ martensite, where the velocity of the specimen during the modification procedure does not affect the phase composition of the modified surfaces. The hardness values at the sample treated with 5 mm/s speed motion are lower than that treated at speed of sample movement of 10 mm/s.
Investigation of the change in wettability properties and corrosion behavior of AISI 304 after laser surface texturing
Authors: Adijāns I , Lazov L , Ilieva M , Nikolova M P 
Published: May 2023

Abstract
Stainless steel is a widely used material in industry, architecture, and medical instruments. However, after various thermal processing of stainless steels, chromium carbides can be formed, which locally depletes the chromium available to form a passive film and reduces the corrosion performance. Laser surface treatment can change the surface chemistry of the steel and improve some electrochemical characteristics. However, these characteristics are influenced by the laser power, pulse width, distance between the lines, scanning speed, etc., which all change the surface chemistry and characteristics of laser surface texturing. Simultaneously, the ability to repel liquids that cause corrosion actions could combine to enhance corrosion performance. Since the wettability of a solid surface depends both on its topography and chemical nature, the micro structuring of an austenitic steel surface is an effective way of fabricating hydrophobic or super hydrophobic corrosion-resistant surfaces. For this reason, this study discusses the effect of laser power in the impact zone and the distance between raster lines on the microstructure, wettability, and corrosion resistance of austenitic steel (AISI 304) when exposed to nanosecond fiber laser radiation. The results indicate that parameter-controlled micro structuring can be used to form both hydrophilic and hydrophobic surfaces with different electrochemical performances.
Investigation of the influence of the processing speed and the linear pulse density of the laser surface texturing process
Authors: Adijāns I , Lazov L , Ilieva M , Nikolova M P 
Published: May 2023

Abstract
Fine-tuning laser parameters is necessary to achieve the desired quality of the process of laser surface texturing. This requires a set of experiments to assess the influence of the main process parameters on the quality of the surface of a treated alloy. By varying the laser parameters, different laser-material interactions, such as heating, melting, or evaporation can be observed. This study analyzes the influence of two interrelated processing parameters in laser surface texturing – the speed of beam motion on the surface on the one hand, and, on the other, the linear pulse density. They ultimately have a direct impact on the resulting microstructure, hydrophilicity, and electrochemical properties of austenitic steel (AISI 304). By adjusting the pulse repetition rate of a 1064-nm fiber laser from 500 kHz to 1000 kHz at a constant speed of 100 mm/s, the surface wettability changes from hydrophobicity to hydrophilicity. All surfaces treated with laser scanning speeds varying from 20 mm/s to 200 mm/s at a constant rate of 500 kHz are hydrophobic. As a result, the changed ability to repel liquids alters the corrosion properties of the steel in a 0.5 M H2SO4 solution. The results allow one to distinguish ranges of laser-beam parameters that could be useful in selecting certain properties of the stainless-steel surface layer.