bluuebunny/crossref_metadata_2025_split huggingface dataset:
The effects of pump pulse fluence on the output energy and amplified spontaneous emission of a femtosecond regenerative amplifier
Authors: Sadegh Kazempourfard Mohammad , Nadgaran Hamid , Mousavi Seyed Mahdi 
Published: December 2021

Abstract
In this paper, the effects of pump pulse fluence on the output energy and amplified spontaneous emission (ASE) of a femtosecond regenerative amplifier are investigated. One can easily enhance the output energy of laser amplifiers by increasing their pump fluence. This in turn can increase the ASE and reduce the performance of amplifiers in terms of output beam quality, beam stability, etc. This effect would eventually lead to what is called ‘temporal intensity contrast deterioration’. In this work, it is shown that an optimum state of the pump pulse fluence can indeed optimize the amount of the output energy from a regenerative amplifier without much reducing the performance of the amplifier due to the higher ASE. Temporal gain characteristics were employed to achieve this optimum value for a better design, performance, and maintenance of femtosecond laser amplifiers. The results of the current study can be effectively used in designing a wide range of regenerative amplifiers for femtosecond pulses.
Proton-neutron symplectic model description of 20Ne
Authors: Ganev H. G. 
Published: December 2021

Abstract
A microscopic description of the low-lying positive-parity rotational bands in 20Ne is given within the framework of the symplectic-based proton-neutron shell-model approach provided by the proton-neutron symplectic model (PNSM). For this purpose, a model Hamiltonian is adopted. This includes an algebraic interaction lying in the enveloping algebra of the

dynamical group of the PNSM, which introduces both horizontal and vertical mixings of different

irreducible representations within the

irreducible collective space of 20Ne. A good overall description is obtained for the excitation energies of the ground and first two excited β bands, including the ground state intraband

quadrupole collectivity and the known interband

transition probabilities between the low-lying collective states, without utilizing an effective charge.
The Origin of The Soft X-Ray Excess in the Seyfert 1.5 Galaxy ESO 362-G18
Authors: Zhong Xiao-Gu , Wang Jian-Cheng 
Published: December 2021

Abstract
We review the Seyfert 1.5 Galaxy ESO 362-G18 for exploring the origin of the soft X-ray excess. The Warm Corona and Relativistic Reflection models are two main scenarios to interpret the soft X-ray excess in active galactic nuclei at present. We use the simultaneous X-ray observation data of XMM-Newton and NuSTAR on 2016 September 24 to perform spectral analysis in two steps. First, we analyze the time-average spectra by using Warm Corona and Relativistic Reflection models. Moreover, we also explore the Hybrid model, Double Reflection model and Double Warm Corona model. We find that both the Warm Corona and Relativistic Reflection models can interpret the time-average spectra well but cannot be distinguished easily based on the time-averaged spectra fit statistics. Second, we add the rms and covariance spectra to perform the spectral analysis with time-average spectra. The result shows that the warm corona could reproduce all of these spectra well. The hot, optical thin corona and neutral distant reflection will increase their contribution with the temporal frequency, meaning that the corona responsible for X-ray continuum comes from the inner compact X-ray region and the neutral distant reflection is made of some moderate scale neutral clumps.
Quantum transport simulation of the two-dimensional GaSb transistors
Authors: Wang Panpan , Han Songxuan , Quhe Ruge 
Published: December 2021

Abstract
Owing to the high carrier mobility, two-dimensional (2D) gallium antimonite (GaSb) is a promising channel material for field-effect transistors (FETs) in the post-silicon era. We investigated the ballistic performance of the 2D GaSb metal–oxide–semiconductor FETs with a 10 nm-gate-length by the ab initio quantum transport simulation. Because of the wider bandgap and better gate-control ability, the performance of the 10-nm monolayer (ML) GaSb FETs is generally superior to the bilayer counterparts, including the three-to-four orders of magnitude larger on-current. Via hydrogenation, the delay-time and power consumption can be further enhanced with magnitude up to 35% and 57%, respectively, thanks to the expanded bandgap. The 10-nm ML GaSb FETs can almost meet the International Technology Roadmap for Semiconductors (ITRS) for high-performance demands in terms of the on-state current, intrinsic delay time, and power-delay product.
Janus MSiGeN4 (M = Zr and Hf) monolayers derived from centrosymmetric β-MA2Z4: A first-principles study
Authors: Guo Xiaoshu , Guo Sandong 
Published: December 2021

Abstract
A two-dimensional (2D) MA2Z4 family with

and

phases has been attracting tremendous interest, the MoSi2N4 and WSi2N4 of which have been successfully fabricated (
Science 369, 670 (2020)). Janus monolayers have been achieved in many 2D families, so it is interesting to construct a Janus monolayer from the MA2Z4 family. In this work, Janus MSiGeN4 (M = Zr and Hf) monolayers are predicted from

-MA2Z4, which exhibit dynamic, mechanical and thermal stabilities. It is found that they are indirect band-gap semiconductors by using generalized gradient approximation (GGA) plus spin-orbit coupling (SOC). With biaxial strain

from 0.90 to 1.10, the energy band gap shows a nonmonotonic behavior due to a change of conduction band minimum (CBM). A semiconductor to metal transition can be induced by both compressive and tensile strains, and the phase transformation point is about 0.96 for compressive strain and 1.10 for tensile strain. The tensile strain can change the positions of CBM and valence band maximum (VBM), and can also induce the weak Rashba-type spin splitting near CBM. For MSiGeN4 (M = Zr and Hf) monolayers, both an in-plane and out-of-plane piezoelectric response can be produced, when a uniaxial strain in the basal plane is applied, which reveals the potential as piezoelectric 2D materials. The high absorption coefficients in the visible light region suggest that MSiGeN4 (M = Zr and Hf) monolayers have potential photocatalytic applications. Our works provide an idea to achieve a Janus structure from the MA2Z4 family, and can hopefully inspire further research exploring Janus MA2Z4 monolayers.
Novel synthesis of cerium oxide nano photocatalyst by a hydrothermal method
Authors: Ali Fowziya Shaik , Al Marzouqi Faisal , Banu A. Afroos , Fathima M. Ismail , Jahangir A. R. Mohamed , Rafi K. Mohamed , Ayeshamariam A. 
Published: December 2021

Abstract
Crystalline cubic cerium oxide nano particles have been synthesized from cerium (III) nitrate (Ce (NO3)3.6H2O) and sodium hydroxide by a hydrothermal method. The effect of three different molar ratios of the NaOH precipitating agent on structural, optical, and photo catalytic activity was investigated. The synthesized cerium oxide nano particles were characterized by X-ray diffraction (XRD), a UV–vis spectrometer, scanning electron microscope (SEM), energy-dispersive X-ray spectroscopy (EDAX), Raman spectroscopy and X-ray photo electron spectroscopy (XPS). According to the findings, hydrothermally synthesized cerium oxide NPs have a high efficiency for photocatalytic degradation of methylene blue when exposed to UV light. Environmental water pollution is the major issue of the atmosphere. To get fresh water, humans could search the resources to purify the water in simple way and degradation is the one of the methods to purify salt water.
Fabrication and characterization of AlGaN/GaN HEMTs with high power gain and efficiency at 8 GHz
Authors: Wang Quan , Chen Changxi , Li Wei , Qin Yanbin , Jiang Lijuan , Feng Chun , Wang Qian , Xiao Hongling , Chen Xiufang , Liu Fengqi , Wang Xiaoliang , Xu Xiangang , Wang Zhanguo 
Published: December 2021

Abstract
State-of-the-art AlGaN/GaN high electron mobility structures were grown on semi-insulating 4H-SiC substrates by MOCVD and X-band microwave power high electron mobility transistors were fabricated and characterized. Hall mobility of 2291.1 cm2/(V·s) and two-dimensional electron gas density of 9.954 × 1012 cm–2 were achieved at 300 K. The HEMT devices with a 0.45-μm gate length exhibited maximum drain current density as high as 1039.6 mA/mm and peak extrinsic transconductance of 229.7 mS/mm. The f
T of 30.89 GHz and f
max of 38.71 GHz were measured on the device. Load-pull measurements were performed and analyzed under (–3.5, 28) V, (–3.5, 34) V and (–3.5, 40) V gate/drain direct current bias in class-AB, respectively. The uncooled device showed high linear power gain of 17.04 dB and high power-added efficiency of 50.56% at 8 GHz when drain biased at (–3.5, 28) V. In addition, when drain biased at (–3.5, 40) V, the device exhibited a saturation output power density up to 6.21 W/mm at 8 GHz, with a power gain of 11.94 dB and a power-added efficiency of 39.56%. Furthermore, the low f
max/f
T ratio and the variation of the power sweep of the device at 8 GHz with drain bias voltage were analyzed.
Humidity sensing properties of spray deposited Fe doped TiO2 thin film
Authors: Gapale Dipak L , Bardapurkar Pranav P. , Arote Sandeep A. , Dalvi Sanjaykumar , Baviskar Prashant , Borse Ratan Y 
Published: December 2021

Abstract
In the present work, ferrite (Fe) doped TiO2 thin films with different volume percentage (vol%) were synthesized using a spray pyrolysis technique. The effect of Fe doping on structural properties such as crystallite size, texture coefficient, microstrain, dislocation densities etc. were evaluated from the X ray diffratometry (XRD) data. XRD data revealed a polycrystalline anatase TiO2 phase for sample synthesized up to 2 vol% and mixed anatase and rutile crystalline phase for sample synthesized at 4 vol% Fe doped TiO2. The crystalline size was observed to decrease with increase in Fe dopant vol% and also other structural parameters changes with Fe dopant percentage. In the present work, electrical resistance was observed to decrease with a rise in Fe dopant vol% and temperature of the sample. Thermal properties like temperature coefficient of resistance and activation energy also showed strong correlation with Fe dopant vol%. Humidity sensing properties of the synthesized sample altered with a change in Fe dopant vol%. In the present paper, maximum sensitivity of about 88.7% for the sample synthesized with 2 vol% Fe doped TiO2 and also the lowest response and recovery time of about 52 and 3 s were reported for the same sample.
Framework for TCAD augmented machine learning on multi- I–V characteristics using convolutional neural network and multiprocessing
Authors: Hirtz Thomas , Huurman Steyn , Tian He , Yang Yi , Ren Tian-Ling 
Published: December 2021

Abstract
In a world where data is increasingly important for making breakthroughs, microelectronics is a field where data is sparse and hard to acquire. Only a few entities have the infrastructure that is required to automate the fabrication and testing of semiconductor devices. This infrastructure is crucial for generating sufficient data for the use of new information technologies. This situation generates a cleavage between most of the researchers and the industry. To address this issue, this paper will introduce a widely applicable approach for creating custom datasets using simulation tools and parallel computing. The multi-I–V curves that we obtained were processed simultaneously using convolutional neural networks, which gave us the ability to predict a full set of device characteristics with a single inference. We prove the potential of this approach through two concrete examples of useful deep learning models that were trained using the generated data. We believe that this work can act as a bridge between the state-of-the-art of data-driven methods and more classical semiconductor research, such as device engineering, yield engineering or process monitoring. Moreover, this research gives the opportunity to anybody to start experimenting with deep neural networks and machine learning in the field of microelectronics, without the need for expensive experimentation infrastructure.
On electron acceleration by mildly-relativistic shocks: PIC simulations
Authors: Romansky V I , Bykov A M , Osipov S M 
Published: December 2021

Abstract
Radio observations revealed a presence of relativistic supernovae - a class of objects intermediate between the regular supernovae and gamma-ray bursts. The typical Lorentz-factors of plasma flows in relativistic radio-bright supernovae were estimated to be about 1.5. Mildly relativistic shocks in electron-ion plasmas are known to efficiently accelerate radio-emitting electrons if the shock is subluminous. The inclination angle of the velocity of subluminous shock to the ambient magnetic field should be below a critical angle which depends on the Mach number and the plasma magnetization parameter. In this paper we present particle-in-cell modeling of electron acceleration by mildly-relativistic collisionless shock of different obliquity in a plasma with ratio of the magnetic energy to the bulk kinetic energy σ ≈ 0.004 which is of interest for the relativistic supernovae modeling. It was shown earlier that a development of the ion scale Bell-type instability in electron-ion relativistic shock may have a strong influence on the electron injection and acceleration. In the time period of about

1500

ω

p
i

−
1

(ωpi
is the ion plasma frequency) after the shock initialization the magnetic field fluctuations generated by Bell’s instability may significantly decreases number of accelerated electrons even in a sub-luminous shock. We study here the evolution of the electron spectra of subluminous shocks of different obliquity. This is important to for modeling of synchrothron spectra from relativistic supernovae.
The candidates for Class I methanol masers
Authors: Nesterenok A V 
Published: December 2021

Abstract
The collisional excitation of methanol molecule in non-dissociative magnetohydro-dynamic shock waves is considered. All essential chemical processes that determine methanol abundance in the gas are taken into account in the shock model. The large velocity gradient approximation is used in the calculations of energy level populations of the molecule. We calculate the optical depth for inverted methanol transitions, and present the list of candidates for Class I methanol masers that have collisional pumping mechanism.
Self-consistent Monte Carlo model of particle acceleration by relativistic shocks
Authors: Osipov S M , Bykov A M , Lemoine M 
Published: December 2021

Abstract
We present a self-consistent Monte Carlo model of particle acceleration by relativistic shock waves. The model includes the magnetic field amplification in the shock upstream by cosmic ray driven plasma instabilities. The parameters of the Monte Carlo model are obtained based on PIC calculations. We present the spectra of accelerated particles simulated in the frame of the model.
Interaction of rotational discontinuities with energetic ions in the precursor of the Earth’s bow shock
Authors: Kropotina Julia A , Artemyev Anton V. , Bykov Andrei M. , Vainchtein Dmitri L. 
Published: December 2021

Abstract
We combined in-situ solar wind observations by ARTEMIS and MMS missions with kinetic hybrid simulations to study the interaction of solar wind rotational discontinuities (RDs) with the foreshock of the Earth’s bow shock. We found that whistler modes excited by diffuse energetic particles were strongly coupled with RDs and lead to their temporary dissociation. At the same time, RDs trigger the steepening of whistler waves and the generation of ’shocklets’ - small localised shock-like structures, capable of trapping energetic particles and growing up by absorbing the particles energy.
Fundamental parameters modeling for the lunar telescope
Authors: Andreev A O , Petrova N K , Nefedyev Y A , Zagidullin A A 
Published: December 2021

Abstract
The powerful flow of highly accurate and multiparameter information produced by spacecrafts has caused a surge interest in the industrial robotic exploration of the Moon and manned flight to Mars after the creation of long-term lunar bases. The modern level of both ongoing and planned lunar studies is characterized by a high level of observation accuracy and a large variety of observation methods. The study of the Moon’s rotational parameters (MRP) is of important value. For this reason, new methods for analyzing big data sets on observation of MRP and extracting the highest possible amount of scientific information from them are needed. Such space technologies require the creation of in-situ telescopes on the Moon. The long-term laser measurements have supplied comprehensive observational information about the Moon. This allows for a description of the Moon’s dynamics with the accuracy required at the current stage - the error of determining the distance to the Moon should be less than a meter, while the one of establishing rotational parameters - arc milliseconds. Nevertheless, there is a necessity to obtain observation data independent of laser measurements. One of the ways to do it is to place on the lunar surface one or several optical telescopes, that will allow determining lunar rotational parameters by measuring the trajectories of the stars and will also be used to solve astrophysical and astrometric problems in the future. This work considers the results of computer modeling of observations taken by lunar in-situ telescopes located at various selenographic latitudes. The sensitivity of MRP to the observed selenographic coordinates of the stars is assessed. Based on the analysis of the simulation results, the optimum location of the telescope is concluded to be at a latitude of 30–45°. The constructive suggestions on the described experiment’s implementation are presented in the paper. The details that will allow implementing or declining the practical implementation of the in-situ telescope are discussed.
Structural analysis of the comet 45P/Honda based on isophote modeling
Authors: Churkin K O , Andreev A O , Nefedyev Y A , Arkhipova A A , Demina N Y 
Published: December 2021

Abstract
The work focuses on using the isophote method to construct a 45P/Honda comet model. At the same time, important problems were solved for modeling the physical surface of a comet and studying the structure of the cometary nucleus. This is due to the fact that, on the basis of modern studies of meteoroids, complex internal processes and dynamic phenomena on their surface have been discovered. The study of comet nuclei is of great importance, since, according to the theory of their formation, they were formed from the matter of the protoplanetary disk. Thus, modeling and analysis of the structure of various comets make it possible to create a more accurate theory of their evolution. This made it possible to evaluate the structural parameters more accurately and reliably. This allowed for the evaluation of the structural parameters more accurately and reliably. Isophotes of the nucleus, coma and tail of comet 45P/Honda were determined. Depending on the point where the comet is located on the trajectory of its orbit, one can see structural changes in the comet’s brightness from the nucleus to the peripheral region. Near the cometary nucleus, the isophotes are circular in shape. If in the center of the model the isophotes have a shape close to narrow rings, then elongations in the direction of the cometary tail and thickening of their structure appear towards the peripheral regions. Large and small tail rays can be distinguished, and the nucleus is well marked. In the future, the author’s method for modeling isophotes, developed in this work, will allow studying the structure of various cometary objects, and, based on the results, determine the degree of comet activity. On the other hand, about the development of the theory of dynamic processes and the evolution of the Solar system, one can use the data on changes in cometary activity in the process of its movement around the Sun.
Unusual asteroid 2020 SO: astrometric investigation of the American rocket booster that returned to near-Earth space
Authors: Petrova S N , Devyatkin A V , Gorshanov D L , L’vov V N , Rusov S A 
Published: December 2021

Abstract
In the frame of this study astrometric observations of an unusual object 2020 SO - a newly discovered asteroid that turned out to be a Centaur upper-stage booster from 1960s - during its two close approaches to the Earth in December, 2020 and February, 2021 were carried out using two telescopes of Pulkovo observatory. The orbit of the object in question was determined and its future orbital evolution was modelled.
Constraints on the temperature-density relation of the intergalactic medium with non-negligible absorber spatial structure
Authors: Telikova K N , Shternin P S , Balashev S A 
Published: December 2021

Abstract
We investigate evolution of physical parameters of the intergalactic medium using an analysis of Lya forest lines detected towards distant quasars. We used the enlarged sample of 98 quasars obtained with Keck/HIRES and VLT/UVES. We show that taking into account a finite spatial size of absorbers, regulated by pressure smoothing, significantly affects the inferred thermal parameters of the intergalactic gas, such as the hydrogen photoionization rate and parameters of the temperature-density relation. Using Bayesian framework we constrained for the first time the scale parameter between the Jeans length and characteristic size of the absorbers. We also discuss limitations of the method based on the analysis of the minimal broadending of Lya lines, which stem from the patchy nature of He II reionization.
The influence of small-scale magnetic field on the heating of J0250+5854 polar cap
Authors: Barsukov D P , Matevosyan A A , Morozov I K , Popov A N , Vorontsov M V 
Published: December 2021

Abstract
The influence of surface small-scale magnetic field on the heating of PSR J0250+5854 polar cap is considered. It is assumed that the polar cap is heated only by reverse positrons accelerated in pulsar diode. It is supposed that pulsar diode is located near the star surface (polar cap model) and operates in the steady state space charge-limited flow regime. The reverse positron current is calculated in the framework of two models: rapid and gradually screening. To calculate the production rate of electron-positron pairs we take into account only the curvature radiation of primary electrons and its absorption in magnetic field. It is assumed that some fraction of electron-positron pairs may be created in bound state that can later be photoionized by thermal photons from star surface.