bluuebunny/crossref_metadata_2025_split huggingface dataset:
Simulation of energy transport by dark matter scattering in stars
Authors: Banks Hannah , Ansari Siyam , Vincent Aaron C. , Scott Pat 
Published: April 2022

Abstract
Asymmetric dark matter (ADM) that is captured in stars can
act as an efficient conductor of heat. Small ADM-induced changes in
a star's temperature gradient are known to alter neutrino fluxes and
asteroseismological signatures, erase convective cores and modify a
star's main sequence lifetime. The Sun's proximity to us makes it an
ideal laboratory for studying these effects. However, the two
formalisms commonly used to parametrize such heat transport were
developed over 30 years ago, and calibrated with a single set of
simulations. What's more, both are based on assumptions that break
down at the Knudsen transition, where heat transport is
maximized. We construct a Monte Carlo simulation to exactly solve
the Boltzmann collision equation, determining the steady-state
distribution and luminosity carried in stars by ADM with cross
sections that depend on velocity and momentum. We find that,
although the established (Gould & Raffelt) formalism based on local
thermal equilibrium does well for constant cross sections, the
isothermal (Spergel & Press) method actually performs better across
all models with a simple, universal rescaling function. Based on
simulation results, we provide recommendations on the
parametrization of DM heat transport in stellar evolution models.
Characterization of the polarized synchrotron emission from Planck and WMAP data
Authors: Martire F.A. , Barreiro R.B. , Martínez-González E. 
Published: April 2022

Abstract
The purpose of this work is to characterize the diffuse
Galactic polarized synchrotron, which is the dominant CMB foreground
emission at low frequency. We present EE, BB, and EB power spectra
estimated from polarization frequency maps at 23 and 30 GHz as
observed respectively by the WMAP K-band and the
Planck lowest frequency channel, for a set of six sky
regions covering from 30% to 94% of the sky. We study the
synchrotron polarization angular distribution and spectral energy
distribution (SED) by means of the so-called pseudo-C
ℓ
formalism, provided by the NaMaster package, in the
multipole interval 30 ≤ ℓ ≤ 300. Best results are
obtained cross-correlating Planck and WMAP
data. The EE and BB angular power spectra show a steep decay of the
spectral amplitude as a function of multipole, approximated by a
power law CEE,BB
∝ ℓαEE,BB
, with
αEE = -2.95 ± 0.04 and αBB = -2.85 ± 0.14. The B/E
power asymmetry is proved with a B-to-E ratio, computed as the
amplitude ratio at the pivot multipole ℓ = 80, of
0.22 ± 0.02. The EB cross-component is compatible with zero at
1σ, with an upper constraint on the EB/EE ratio of 1.2% at
the 2σ level. We show that the EE and BB power-law model with
null EB cross-correlation describes reasonably well the diffuse
synchrotron polarization emission for the full sky if the bright
Galactic center and point sources are masked. The recovered SED
shows power-law spectral indices βEE
= -3.00 ± 0.10 and
βBB
= -3.05 ± 0.36 compatible between themselves, in the
frequency range 23–30 GHz. Results also seem to indicate that the
SED gets steeper from low to high Galactic latitude.
X-Ray Performance of a Customized Large-format Scientific CMOS Detector
Authors: Wu Qinyu , Jia Zhenqing , Wang Wenxin , Ling Zhixing , Zhang Chen , Zhang Shuangnan , Yuan Weimin 
Published: April 2022

Abstract
In recent years, the performance of Scientific Complementary Metal Oxide Semiconductor (sCMOS) sensors has been improved significantly. Compared with charge-coupled Device sensors, sCMOS sensors have various advantages, making them potentially better devices for optical and X-ray detection, especially in time-domain astronomy. After a series of tests of sCMOS sensors, we proposed a new dedicated high-speed, large-format X-ray detector in 2016 cooperating with Gpixel Inc. This new sCMOS sensor has a physical size of 6 cm × 6 cm, with an array of 4096 × 4096 pixels and a pixel size of 15 μm. The frame rate is 20.1 fps under current condition and can be boosted to a maximum value around 100 fps. The epitaxial thickness is increased to 10 μm compared to the previous sCMOS product. We show the results of its first taped-out product in this work. The dark current of this sCMOS is lower than 10 e− pixel−1 s−1 at 20°C, and lower than 0.02 e− pixel−1 s−1 at −30°C. The fixed pattern noise and the readout noise are lower than 5 e− in high-gain situation and show a small increase at low temperature. The energy resolution reaches 180.1 eV (3.1%) at 5.90 keV for single-pixel events and 212.3 eV (3.6%) for all split events. The continuous X-ray spectrum measurement shows that this sensor is able to response to X-ray photons from 500 eV to 37 keV. The excellent performance, as demonstrated from these test results, makes sCMOS sensor an ideal detector for X-ray imaging and spectroscopic application.
Photometric Redshifts and Galaxy Clusters for DES DR2, DESI DR9, and HSC-SSP PDR3 Data
Authors: Zou Hu , Sui Jipeng , Xue Suijian , Zhou Xu , Ma Jun , Zhou Zhimin , Nie Jundan , Zhang Tianmeng , Feng Lu , Shen Zhixia , Wang Jiali 
Published: April 2022

Abstract
Photometric redshift (photoz) is a fundamental parameter for multi-wavelength photometric surveys, while galaxy clusters are important cosmological probes and ideal objects for exploring the dense environmental impact on galaxy evolution. We extend our previous work on estimating photoz and detecting galaxy clusters to the latest data releases of the Dark Energy Spectroscopic Instrument (DESI) imaging surveys, Dark Energy Survey (DES) and Hyper Suprime-Cam Subaru Strategic Program (HSC-SSP) imaging surveys and make corresponding catalogs publicly available for more extensive scientific applications. The photoz catalogs include accurate measurements of photoz and stellar mass for about 320, 293 and 134 million galaxies with r < 23, i < 24 and i < 25 in DESI DR9, DES DR2 and HSC-SSP PDR3 data, respectively. The photoz accuracy is about 0.017, 0.024 and 0.029 and the general redshift coverage is z < 1, z < 1.2 and z < 1.6, respectively for those three surveys. The uncertainty of the logarithmic stellar mass that is inferred from stellar population synthesis fitting is about 0.2 dex. With the above photoz catalogs, galaxy clusters are detected using a fast cluster-finding algorithm. A total of 532,810, 86,963 and 36,566 galaxy clusters with the number of members larger than 10 is discovered for DESI, DES and HSC-SSP, respectively. Their photoz accuracy is at the level of 0.01. The total mass of our clusters is also estimated by using the calibration relations between the optical richness and the mass measurement from X-ray and radio observations. The photoz and cluster catalogs are available at ScienceDB (https://www.doi.org/10.11922/sciencedb.o00069.00003) and PaperData Repository (https://doi.org/10.12149/101089).
The First Photometric Study of AH Mic Contact Binary System
Authors: Poro Atila , Blackford M. G. , Ranjbar Salehian S. , Jahangiri E. , Samiei Dastjerdi M. , Gozarandi M. , Karimi R. , Madayen T. , Bakhshi E. , Hedayati F. 
Published: April 2022

Abstract
The first multi-color light curve analysis of the AH Mic binary system is presented. This system has very few past observations from the southern hemisphere. We extracted the minima times from the light curves based on the Markov Chain Monte Carlo (MCMC) approach and obtained a new ephemeris. To provide modern photometric light curve solutions, we used the Physics of Eclipsing Binaries (PHOEBE) software package and the MCMC approach. Light curve solutions yielded a system temperature ratio of 0.950, and we assumed a cold starspot for the hotter star based on the O’Connell effect. This analysis reveals that AH Mic is a W-subtype W UMa contact system with a fill-out factor of 21.3% and a mass ratio of 2.32. The absolute physical parameters of the components are estimated by using the Gaia Early Data Release 3 (EDR3) parallax method to be M

h
(M
⊙) = 0.702(26), M

c
(M
⊙) = 1.629(104), R

h
(R
⊙) = 0.852(21), R

c
(R
⊙) = 1.240(28), L

h
(L
⊙) = 0.618(3) and L

c
(L
⊙) = 1.067(7). The orbital angular momentum of the AH Mic binary system was found to be 51.866(35). The components’ positions of this system are plotted in the Hertzsprung–Russell diagram.
Constraining Brans–Dicke Cosmology with the CSST Galaxy Clustering Spectroscopic Survey
Authors: Chen Anda , Gong Yan , Wu Fengquan , Wang Yougang , Chen Xuelei 
Published: April 2022

Abstract
The Brans–Dicke (BD) theory is the simplest Scalar-Tensor theory of gravity, which can be considered as a candidate of modified Einstein’s theory of general relativity. In this work, we forecast the constraints on BD theory in the CSST galaxy clustering spectroscopic survey with a magnitude limit ∼23 AB mag for point-source 5σ detection. We generate mock data based on the zCOSMOS catalog and consider the observational and instrumental effects of the CSST spectroscopic survey. We predict galaxy power spectra in the BD theory from z = 0 to 1.5, and the galaxy bias and other systematical parameters are also included. The Markov Chain Monte Carlo technique is employed to find the best-fits and probability distributions of the cosmological and systematical parameters. A BD parameter ζ is introduced, which satisfies

ζ
=
ln

1
+

1

ω

. We find that the CSST spectroscopic galaxy clustering survey can give ∣ζ∣ < 10−2, or equivalently

∣
ω
∣
>

(

10

2

)

and

∣

G

̇

/

G
∣
<

10

−
13

, under the assumption ζ = 0. These constraints are almost at the same order of magnitude compared to the joint constraints using the current cosmic microwave background, baryon acoustic oscillations and Type Ia supernova data, indicating that the CSST galaxy clustering spectroscopic survey would be powerful for constraining the BD theory and other modified gravity theories.
Formation of oxide films on a curved aluminium surface upon anodic oxidation
Authors: Tzaneva B , Videkov V , Bankova A , Mitov M , Dobrev D 
Published: April 2022

Abstract
The aluminium oxide obtained by anodization in acidic solutions has a highly ordered nanoporous structure consisting of straight parallel pores. The oxide layer has good electrical insulating properties on planar surfaces. However, the electrochemical formation of nanoporous film on convex surface induces effects such as crack formation and deterioration of the insulating properties. The present work is focused on investigating the conditions of growth of a thick oxide layer on aluminium wires with a diameter of 0.2 mm to 0.5 mm. In order to prevent cracking, the oxide growth was carried out by reducing the anodization voltage according to a mathematical model in view of obtaining conical pores. In this study, the minimum thickness at which a crack-free oxide layer grows was determined.
Optical properties of nanostructured bimetallic films from the Ag-In and Ag-Sb systems and their surface-enhanced fluorescence application
Authors: Katrova V , Hristova-Vasileva T , Atanasova A , Strijkova V , Todorov R 
Published: April 2022

Abstract
The possibility for tuned excitation of surface plasmon resonance in Ag-In and Ag-Sb films with different compositions and thicknesses was studied in terms of preparation and microstructural and optical properties. The analyses show that plasmon excitation can be achieved both by changing the thickness of the deposited bimetallic films and by varying their composition. The imaginary ε'' part of the complex permittivity of the thin films has a maximum due to the transverse oscillations of free electrons in the range of 1 eV to 3.5 eV. The films’ applicability as amplifying substrates in surface-enhanced fluorescence was tested. Tryptophan and Cu (II)-phthalocyanine (CuPc) dye were used to analyze the efficiency of the localized surface plasmon resonance excitation in the ultraviolet spectral region. Amplification enhancing coefficient of 4.17 times was obtained in the case of CuPc dye.
Structure and phase composition study of thin TiO2:C films deposited by r.f. magnetron sputtering
Authors: Milenov T , Karaivanova D , Angelov O , Terziyska P , Avdeev G , Karashanova D , Georgieva B , Genkov K , Dimov D , Ivanov K , Kolev S , Valcheva E 
Published: April 2022

Abstract
Thin films of TiO2 doped with carbon were deposited on 15×25×1 mm3 glass substrates by r.f. magnetron co-sputtering of TiO2 target and carbon plates on their erosion zone in Ar + air atmosphere (0.5 Pa and 0.6 Pa, respectively). Two different process parameters were varied in different experiments: the total area of the carbon plates (84 mm2, 560 mm2, 830 mm2 or 1480 mm2) and the radial distance from the center of the circle of the erosion zone with maximum rate of sputtering (2 cm or 4 cm). The as-deposited and annealed (air, 400 °C, 1 h) thin films with thicknesses of 40 - 60 nm were studied by ellipsometry, grazing incidence X-ray diffractometry (GIXRD), Raman spectroscopy, transmission (TEM) and scanning electron microscopies (SEM). The ellipsometric studies revealed the band gap, as well as the tail states and optical constants of the thin films obtained. The GIXRD patterns revealed a mix of amorphous and nanocrystalline anatase and rutile TiO2 phases in all thin films. The Raman study confirmed this conclusion, but the TEM study showed the presence of some nanocrystalline C20O14Ti3, together with the other TiO2 phases - brookite and nonstoichiometric TiOx phases (anatase and rutile). The effects of annealing at 400 °C in air for 60 min are also discussed.
Characterization of the aerosol field over Sofia, Bulgaria, using contact and passive-remote-sensing methods and instruments
Authors: Evgenieva Ts , Kolev N , Savov P , Gurdev L , Grigorov I , Dreischuh T 
Published: April 2022

Abstract
The atmospheric aerosol particles, called also atmospheric particulate matter, that include also fine dust particles (FDP), are an important factor conditioning many physical processes in the atmosphere, affecting the climate and the air quality, and posing serious potential risks to the human health. In this regard, the regular observation of the atmospheric aerosol load and its dynamics is a valuable source of scientific information concerning these processes, while also allowing the relevant institutions to undertake preventive measures in cases of a dangerous FDP concentration increase. This work is devoted to estimating experimentally, by passive optical sensing and contact measurements, some important integral microphysical and optical characteristics and their dynamics of the aerosol ensembles over Sofia, Bulgaria. The results obtained outline the springtime values of the aerosol number and mass concentration in the near-ground urban atmosphere, the depth of the atmospheric boundary layer, the aerosol optical depth at different optical wavelengths, the water vapor content, and the Ångström exponent at the wavelengths of 440/870 nm.
Duplex surface modification of tool steel - deposition of a WN film and subsequent electron-beam modification
Authors: Valkov S , Ormanova M , Ivanov N , Dechev D , Bezdushnyi R , Petrov P 
Published: April 2022

Abstract
In this study, we demonstrate a combined treatment technique of R18 high-speed tool steel comprising deposition of a WN coating followed by electron-beam surface treatment (EBT). In order to understand the influence of the deposited WN coating on the resultant structure and properties, an uncoated specimen was directly electron-beam treated under the same EBT technological conditions. The structure of the specimens was studied by X-ray diffraction, scanning electron microscopy, and energy-dispersive X-ray spectroscopy. The microhardness was also investigated. The phase composition consisted of a double phase structure of Fe and M6C carbides in both cases. The microstructure was significantly finer in the case of an EBT of the steel with WN coating, leading to a much higher microhardness in comparison with the case without WN.
Depth profiling of very thin HfO2/Al2O3 stacks by ellipsometry
Authors: Karmakov Y , Paskaleva A , Spassov D 
Published: April 2022

Abstract
Ellipsometry (VASE and MAIE) with appropriate algorithms for experimental data interpretation was applied for quantitative characterization of thin Al2O3/HfO2 multilayers formed by atomic layer deposition (ALD) applicable to the fabrication of charge-trapping nonvolatile memories. A substantial benefit of the algorithms is the depth profiling of the stacks. In this work, the depth profiles were retrieved of the HfO2 constituent in very thin (Al2O3:HfO2) stacks embedded in thin Al2O3 surrounding layers. The peculiarities in the achieved depth profiles are used to determine the bi-layer blocks and their sub-layer thicknesses. The influence of a rapid thermal annealing in O2 on the depth profile and the sub-layer thicknesses is studied; substantial changes are thus revealed in the thickness and composition of the stacks. This information could be used in optimizing the dielectric and electrical properties of the stacks and multilayers.
Comparative study of the sidewall shape and proximity effect of the AR-N 7520 negative electron beam resist
Authors: Kostic I , Vutova K , Koleva E , Bencurova A , Konecnikova A , Andok R 
Published: April 2022

Abstract
This paper deals with the performance of the AR-N7520 (Allresist) negative electron beam resist (EB resist) which was selected as an etch mask for the fabrication of gratings on GaAs substrates. The developed resist sidewall shape is crucial for this purpose. The required near-to-vertical sidewall shape can be achieved by optimizing the electron beam lithography (EBL) process based on experimental investigations and computer simulations. The sidewall shape dependence on the EBL parameters (exposure dose, resist pattern, etc.) and the proximity effect are studied.
Finiteness and the swampland
Authors: Hamada Yuta , Montero Miguel , Vafa Cumrun , Valenzuela Irene 
Published: April 2022

Abstract
We view and provide further evidence for a number of swampland criteria, including the weak gravity conjecture, distance conjecture and bounds on the finiteness of the quantum gravity vacua from the prism of the finiteness of black hole entropy. Furthermore we propose that at least all of these swampland statements may be more fundamentally a consequence of the finiteness of quantum gravity amplitudes.
Synthesis and Investigation of Ferroelectric Curie Transition in BaTiO3
Authors: Kumar Ajay , Naskar Sudip , Mandal Dipankar 
Published: April 2022

Abstract
Ferroelectric phase comprising BaTiO3 nanoparticles and nanorods have been prepared by high temperature sintering. The XRD spectra of sintered powder was used to confirm the ferroelectric phase crystallisation. The non-ferroelectric cubic phase to ferroelectric tetragonal phase transition of BaTiO3 was studied by temperature dependent dielectric study. The Curie temperature of 105 °C in sintered nanoparticles was observed from dielectric study of tetragonal phase BaTiO3.
Optoelectronic, microstructural, ecofriendly and photo-catalytic evaluation of Aspartic acid cross-linked Poly (vinyl alcohol)/Copper Oxidenanotubescomposite films
Authors: Amaregouda Yamanappagouda , Gasti Tilak , Kamanna Kantharaju 
Published: April 2022

AbstractThe present work describes design and preparation of aspartic acid (Asp) cross-linked Poly (vinyl alcohol) (PVA)/Copper oxide nanotubes (CuO NTs) composite filmsvia solution casting method.The CuO NTswere prepared by novel biogenic method usingRobiniaPseudoacaciaLeaf Extract.Theprepared CuO NTs and PVA/CuO/Asp nanocomposite filmsarecharacterized by various techniques.The adsorption and photo-catalytic efficiencies of PVA/CuO/Asp nanocomposite films were compared with pristine CuO NTs. The adsorption capacity of PVA/CuO/Asp nanocomposite films showed higher due to presence of active sites, high surface activity and semiconducting nature of CuO NTs and Asp embedded in PVA matrix. The comparative photocatalytic activities of the CuO NTsand PVA/CuO NTs/Asp nanocomposite filmsare examinedagainst methylene blue (MB) as a substrate degradation, and film PVA/CuO NTs/Asp showed highest (up to 77%) degradation compared to other films. The improved photocatalytic behavior of PVA nanocomposite film attributed to its narrower band gapreduces the recombination rate of exited electron-hole, enhanced UV-Vis absorption intensity, extinction coefficient and refractive index, improved utilization of sunlight and enhanced adsorption of dye due to functional groups, biodegradable, surface wettability, hydrophilic surface and self-cleaning nature.
An Investigative Study on the effect of Dopants on Manganese Based Mixed Nano Ferrites Synthesized through Sol-Gel Method
Authors: Jose Dhanya , Mildred Sruthy , Mary Sebastian Rintu , Xavier Sheena 
Published: April 2022

Abstract
The present article investigates the effect of different dopants on manganese based mixed nano ferrites synthesized through sol-gel method.MnF, MnCoF and MnCoMgF (MnFe2O4, Mn0.5Co0.5Fe2O4andMn0.5Co0.25Mg0.25Fe2O4) were synthesized by Sol-gel method. The structural, magnetic and optical properties of the samples were analysed through XRD(X-RayDiffractometer), VSM (Vibrating Sample Magnetometer,) and UV-Visible Spectroscopy. The phase identification and lattice parameter determination were carried out by using X-RayDiffraction and hence the crystallite size and X-Ray density were calculated. Peaks (220), (311), (400), (511), and (440) were obtained from the XRDpattern of the samples, which confirmed their single-phase cubic spinel structure. It was observed that because of the large ionic radius of Co2+ (0.745 Å) ions as compared to that of Fe3+ (0.645 Å) ions, lattice parameter of MnCoF increased in comparison with that of MnF but, the substitution of Mg2+ to MnCoF sample decreased the lattice constant. By investigating the hysteresis loops produced by the samples in the VSM analyses, it was found that the MnF have low coercivity and moderate saturation magnetization amongst the three. The substitution of Mg2+ in MnCoF sample decreased the value of saturation magnetization. UV-Visible analysis was used to determine bandgap energy of three samples.From the Tauc plot, we can observe bandgap energies of 3.202 eV, 3.180 eV and 3.239 eV, for MnF, MnCoF and MnCoMgF respectively.On substituting with the Co2+ in MnF the band gap of sample decreases indicating quantum confinement phenomenon.When substitution was done both Co2+ and Mg2+, the band gap energy value increases.
Effect of plant extracts on structural & morphological features of CuO nano structured material
Authors: Rotti Rajeshwari B. , Ramya M , Venkatesha Babu K R , Sunitha D.V. 
Published: April 2022

Abstract
Cupper oxide (CuO) nano structured material has been synthesized by using eco-friendly simple solution method using plant leaf extracts(Mangifera indica, Carica papaya and Azadirachta indica) as a reducing agent. The obtained material is subjected to calcination at 500 °C for further studies. Powder X-ray diffraction (PXRD) and Fourier transmittance Infrared spectroscopy (FTIR) was performed for the structural confirmation of the calcined CuO samples.The CuO prepared by using Mangifera indica, Carica papaya and Azadirachta indica leaf extracts exhibited flake shape, irregular and spherical structures respectively in scanning electron microscope (SEM) micrographs.In addition, the UV-Visible absorption spectrum was recorded and the energy gap determined by using Tauc relation was 3.5, 3.75 and 3.9eV for Mangifera indica, Carica papaya and Azadirachta indica respectively.