bluuebunny/crossref_metadata_2025_split huggingface dataset:
Measurement of the size of the gamma-ray source in blazar B0218+357 based on microlensing at the 100 GeV energy band
Authors: Vovk Ie. , Neronov A. 
Published: February 2024

Context.Observations of the effect of microlensing in gravitationally lensed quasars can be used to study the structure of active galactic nuclei on distance scales down to the sizes of a supermassive black hole’s powering source activity.Aims.We searched for a microlensing effect in the signal from a gravitationally lensed blazar, B0218+357, in a very-high-energyγ-ray band.Methods.We combined observations of a bright flare of the source in 2014 by theFermiLarge Area Telescope and MAGIC telescopes in the 0.1 − 300 GeV and 65 − 175 GeV energy ranges, respectively. Using the time-delayed leading and trailing signals from two gravitationally lensed images of the source, we measured the magnification factor at the moment of the flare. We used the scaling of the maximal magnification factor with the source size to constrain the size of theγ-ray emission region in the wide 0.1 − 175 GeV energy range.Results.The magnification factor in the very-high-energy band that we derived from our comparison ofFermi/LAT and MAGIC data isμVHE = 25−17+38, which is substantially larger than the factor found in the radio band. This suggests one of the source images is strongly affected by microlensing at the moment of the flare. Assuming that the microlensing is produced by a stellar mass object in the lens galaxy, we constrained the size of the emission region in theE > 100 GeV band to beRVHE = 6.6−5.6+69 × 1014 cm. We note that the spectrum of the microlensed source was unusually hard at the moment of the flare, and we speculate that this hardening may be due to the energy-dependent microlensing effect. This interpretation suggests that the source size decreases with energy in the entire 0.1 − 175 GeV energy range we studied.
Rotation of ZZ Ceti stars as seen by TESS
Authors: Bognár Zsófia , Sódor Ádám 
Published: February 2024

Context. Knowing the rotation rates and masses of white dwarf stars is an important step towards characterising the angular momentum transport mechanism in their progenitors, and coupling the cores of red giants to their envelopes. However, deriving these rotation rates is not an easy task. One can use the rotational broadening of spectral lines, but there is another way to gather reliable information on the stellar rotation periods of pulsators: through studying the splitting effect of rotation on oscillation frequencies.
Aims. We aim to derive stellar rotation periods in the TESS sample for as many white dwarf pulsators as possible.
Methods. We rely on light-curve analysis of the TESS observations, and search for closely spaced frequency multiplets that could be rotationally split pulsation modes. We work with triplet frequencies, even if one or two triplet components are only marginally detectable. We also utilise ground-based observations available from the literature in an attempt to confirm the presence of several triplets.
Results. We successfully identified rotationally split multiplets and derived rotation rates for 14 stars. The fastest rotators we identified have rotation periods of 6.6–10.0 h. The majority of the pulsators rotate with periods of 11.9–47.5 h, while we derived 85.5 and 93.2 h periods for the slowest rotators. In addition to providing stellar mass estimations, our results confirm previous findings that larger-mass WDs rotate faster than their lower-mass counterparts. We determine the rotation periods of four stars for the first time.
Forming localized dust concentrations in a dust ring: DM Tau case study
Authors: Liu Hauyu Baobab , Muto Takayuki , Konishi Mihoko , Chung Chia-Ying , Hashimoto Jun , Doi Kiyoaki , Dong Ruobing , Kudo Tomoyuki , Hasegawa Yasuhiro , Terada Yuka , Kataoka Akimasa 
Published: February 2024

Context. Previous high-angular-resolution 225 GHz (~1.3 mm) continuum observations of the transitional disk DM Tau have resolved an outer ring at 20–120 au radii that is weakly azimuthally asymmetric.
Aims. We aim to examine dust growth and filtration in the outer ring of DM Tau.
Methods. We performed ~0″.06 (~8.7 au) resolution Karl G. Jansky Very Large Array (JVLA) 40–48 GHz (~7 mm; Q band) continuum observations, along with complementary observations at lower frequencies. In addition, we analyzed the archival JVLA observations undertaken since 2010.
Results. Intriguingly, the Q band image resolved the azimuthally highly asymmetric, knotty dust emission sources close to the inner edge of the outer ring. Fitting the 8–700 GHz spectral energy distribution (SED) with two dust components indicates that the maximum grain size (amax) in these knotty dust emission sources is likely ≳300 µm, whereas it is ≳50 µm in the rest of the ring. These results may be explained by a trapping of inwardly migrating “grown” dust close to the ring inner edge. The exact mechanism for developing the azimuthal asymmetry has not yet been identified, which may be due to planet-disk interaction that might also be responsible for the creation of the dust cavity and pressure bump. Otherwise, it may be due to the fluid instabilities and vortex formation as a result of shear motions. Finally, we remark that the asymmetries in DM Tau are difficult to diagnose from the ≳225 GHz observations, owing to a high optical depth at the ring. In other words, the apparent symmetric or asymmetric morphology of the transitional disks may be related to the optical depths of those disks at the observing frequency.
Detection of a cyclotron line in the Be X-ray pulsar IGR J06074+2205
Authors: Roy Kinjal , Sharma Rahul , Manikantan Hemanth , Paul Biswajit 
Published: February 2024

Context. IGR J0607.4+2205 is a transient Be X-ray binary discovered two decades ago. IGR J0607.4+2205 underwent an outburst in 2023 during which it was observed twice with NuSTAR.
Aims. The main goal of this work is to model the broadband X-ray spectrum of IGR J0607.4+2205 during the outburst and to study the variations of the spectral and timing features at different intensities.
Methods. We extracted the light curve and spectrum of the source from the two NuSTAR observations carried out during the recent outburst in the energy range of 3−78 keV. We used the epoch folding technique to find pulsation from the source and to study the changes in emission characteristics from the source with energy across an order of magnitude variation in source luminosity.
Results. IGR J0607.4+2205 shows pulsations with a period of ∼347.6 s during both the observations, with a pulse fraction of ≥50%. The broadband spectrum of the source was modelled using a power-law continuum with a high-energy cutoff. During the first observation, a cyclotron absorption line at ∼51 keV was also present in the source with an optical depth of ∼1.3. However, no cyclotron line feature was detected in the second observation when the source was an order of magnitude fainter. Additionally, soft excess was detected in the second observation, which was modelled with a black body component emerging from close to the neutron star (NS).
Conclusions. We report the first ever detection of a cyclotron line in the broadband spectrum of IGR J0607.4+2205 centred at 51 ± 1 keV. The magnetic field strength of the NS is estimated to be ∼4 × 1012 G from the centroid energy of the absorption line. A significant change is observed in the pulse profile with luminosity during the decay of the outburst, indicating an associated change in the beaming pattern.
Hyperfine-resolved rotational spectroscopy of HCNH+
Authors: Silva Weslley G. D. P. , Bonah Luis , Schmid Philipp C. , Schlemmer Stephan , Asvany Oskar 
Published: February 2024

The rotational spectrum of the molecular ion HCNH+ is revisited using double-resonance spectroscopy in an ion trap apparatus, with six transitions measured between 74 and 445 GHz. Due to the cryogenic temperature of the trap, the hyperfine splittings caused by the 14N quadrupolar nucleus were resolved for transitions up to J = 4 ← 3, allowing for a refinement of the spectroscopic parameters previously reported, especially the quadrupole coupling constant eQq.
Ion transport through short nanopores modulated by charged exterior surfaces
Authors: Ma Long , Liu Zhe , Ai Bowen , Man Jia , Li Jianyong , Wu Kechen , Qiu Yinghua 
Published: February 2024

Short nanopores find extensive applications, capitalizing on their high throughput and detection resolution. Ionic behaviors through long nanopores are mainly determined by charged inner-pore walls. When pore lengths decrease to sub-200 nm, charged exterior surfaces provide considerable modulation to ion current. We find that the charge status of inner-pore walls affects the modulation of ion current from charged exterior surfaces. For 50-nm-long nanopores with neutral inner-pore walls, the charged exterior surfaces on the voltage (surfaceV) and ground (surfaceG) sides enhance and inhibit the ion transport by forming ion enrichment and depletion zones inside nanopores, respectively. For nanopores with both charged inner-pore and exterior surfaces, continuous electric double layers enhance the ion transport through nanopores significantly. The charged surfaceV results in higher ion current by simultaneously weakening the ion depletion at pore entrances and enhancing the intra-pore ion enrichment. The charged surfaceG expedites the exit of ions from nanopores, resulting in a decrease in ion enrichment at pore exits. Through adjustment in the width of charged-ring regions near pore boundaries, the effective charged width of the charged exterior is explored at ∼20 nm. Our results may provide a theoretical guide for further optimizing the performance of nanopore-based applications, such as seawater desalination, biosensing, and osmotic energy conversion.
A versatile beamline for soft x-ray reflectivity, absorption, and fluorescence measurements at Indus-2 synchrotron source
Authors: Modi Mohammed H. , Gupta Rajkumar , Gupta Shruti , Yadav Praveen Kumar , Kant Chander , Lal Sohan , Raghuvanshi V. K. , Kane S. R. 
Published: February 2024

A versatile beamline for performing reflectivity, fluorescence, and absorption experiments in the soft x-ray region of 100–1500 eV is commissioned on a bending magnet port of the Indus-2 synchrotron source. A high vacuum 2-axis reflectometer with x, y, and z sample scanning stages is installed. This reflectometer is used to measure the reflectivity of large samples up to 300 mm in length and 5 kg in weight. This feature is useful for characterizing x-ray optical elements, such as mirrors, gratings, and multilayers. A flange mounted silicon drift detector is installed in the downstream of the reflectometer for soft x-ray fluorescence measurements. The soft x-ray absorption measurements are carried out in the total electron yield and partial fluorescence yield modes. Integration of three different experimental techniques in the experimental station makes the beamline versatile for materials science applications as it provides structural, chemical, and electronic state information by performing the required experiments in an identical environment. The beamline uses a varied line spacing plane grating monochromator and gives a high flux (∼109 to 1011 photon/s) with a moderate resolution (λ/Δλ ~1000–5000). A three-mirror-based higher harmonic setup is incorporated to get rid of harmonics and to get a high spectral purity monochromatic beam with less than 0.1% harmonic content. In the present article, the beamline optical scheme, mechanical configuration, and details of the experimental setups are presented, along with a few representative results of each experimental mode.
English complex premodifiers and their German and Swedish correspondences
Authors: Levin Magnus , Ström Herold Jenny 
Published: February 2024

Abstract
This study concerns English hyphenated premodifiers (science-based targets; lower-back pain)
contrasted with their German and Swedish correspondences. The data stem from the Linnaeus University English-German-Swedish corpus
(LEGS), which contains non-fiction texts, but comparisons are also made to fiction texts from the English-Swedish Parallel Corpus
(ESPC). The study shows that these condensed and complex premodifiers are more frequent in English originals than in English
translations, and more typical of the non-fiction genre than that of fiction. Information density and terminological precision
thus seem to be more important factors for the use of hyphenated premodifiers than creativity and expressiveness. In original
English, two-thirds of the right-hand elements are either nouns or ed-participles. In translated English,
numerals as left-hand elements (three-page document) are less frequent than in original English. Regarding German
and Swedish correspondences, around half are premodifiers. Postmodifiers in the form of prepositional phrases and relative clauses
are more frequent in Swedish than in German, which instead “overuses” premodifying extended attributes. Compound
adjectives/participles and compound nouns are the most frequent correspondences in both German and Swedish. In almost half the
instances, German and Swedish translators choose the same correspondents, indicating a high degree of similarity in the structural
preferences in the two target languages.
Evaluating mobility extraction reliability in non-ideal organic transistors utilizing weak epitaxy-grown pentacene films
Authors: Tang Deqian , Yuan Beibei , Wang Haibo 
Published: February 2024

Abstract
Organic thin-film transistors (OTFTs) have exhibited enhanced carrier mobilities, albeit often accompanied by non-ideal electrical characteristics, posing challenges in accurately assessing device performance. Therefore, it is critical to understand the reliability of mobility values derived from these non-ideal current–voltage curves. In this study, high-quality pentacene films and their OTFTs were fabricated by using organic weak-epitaxy growth technology. We focused on investigating the relationship between effective mobilities and contact resistance by varying the interlayer thicknesses of MoO3 while maintaining the optimized semiconductor layer unchanged. An inverse correlation between the reliability factors and claimed mobilities is identified. For OTFTs with moderate contact resistance, the effective mobility exhibited minimal variation, remaining within a narrow 10% margin, accompanied high reliability factor. These results indicated the reliability of mobility extraction. Notably, the optimal thickness of MoO3 ranged between 2.0–3.0 nm. In contrast, a thicker MoO3 layer significantly decreased the reliability factor due to a high contact resistance, thereby rendering the effective mobility unreliable. Our works underscore the robustness of the estimation method for OTFTs featuring moderate contact resistance, providing guidance for the evaluation of material and device performance.
Annihilation mechanisms for interacting skyrmions in magnetic nanowire
Authors: Al Saidi W , Bhatti S , Piramanayagam S N , Sbiaa R 
Published: February 2024

Abstract
Magnetic skyrmions are considered potential candidates for spintronics-based memory and logic devices. For achieving high-density and high-speed devices, it is essential to study their interactions. In this paper, the interaction, dynamics and annihilation mechanisms of Néel skyrmions in nanowire confinement under the influence of spin-transfer torque (STT) and edge forces have been studied. Initially isolated, two Néel skyrmions are brought into proximity, leading to distinct interaction scenarios characterized by varying current densities. We explore the impact of these interactions on skyrmion trajectories, size evolution, and annihilation phenomena. Our findings reveal the interplay of skyrmion–skyrmion repulsive forces, edge effects, and the influence of STT, shedding light on the rich dynamics of these topological magnetic textures. Furthermore, we unveil the distinct annihilation mechanisms of the leading and trailing skyrmions under different forces, providing valuable insights into the fundamental physics of skyrmion behavior in confined geometries.
Novel deposition method for gold and platinum nanoparticles on silicon substrates utilizing poly (ethylene glycol) 6000 for MEIS analysis
Authors: Klippel T S , Fonteles Henrique , Torgo Daphne , Selau Felipe , Borges Eduarda , Konrad Bárbara , Trombini Henrique , Morais Jonder , do Carmo M Alves Maria , Benvenutti E V , Baptista D L , P L Grande and 
Published: February 2024

Abstract
The use of nanoparticles has significantly increased in many areas, such as biomedical research, being highly useful as nanoprobes for imaging and as nanocarriers for drug delivery applications. Nevertheless, this potential can only be achieved with the correct characterization of the nanoparticles, since their size and shape can directly affect their biological behavior. In this study, we propose a novel approach for a monolayer deposition of gold and platinum nanoparticles on Si substrates suitable for medium energy ion scattering (MEIS) analysis. The samples were prepared using poly(ethylene glycol) 6000 (PEG 6000) as a coating agent for the substrates, utilizing a spin coater-a versatile, cost-effective, and practical technique. The samples were first analyzed with the RBS technique to assess the adhesion and the overlapping of the nanoparticles in the substrates coated with PEG 6000 and then characterized through the MEIS technique. The analysis through MEIS allowed the determination of the shape, size, and coverage area of the nanoparticles. Scanning and transmission electron microscopy were also performed on the samples, with the results corroborating the findings of the MEIS experiment. Together, the data obtained with microscopy and the MEIS technique suggests the effectiveness of the method in the production of monolayer samples.
High-temperature properties of dry air used as arc quenching medium and its mixture with vaporized
C2F4
: reaction products and critical reduced electric field strength at 300–3000 K
Authors: Yokomizu Y , Kodama N , Yamamoto I , Uchiyama S , Sato M , Nakamura Y , Edo T 
Published: February 2024

Abstract
Recently, electric power equipment manufacturers released a joint statement with the aim of developing high-voltage electrical equipment completely free of fluorinated gases such as fluoroketones and fluoronitriles, which are considered as alternatives to

S

F

6

and artificially produced compounds of F. This paper considers air as a typical gas present naturally in the environment to investigate its high-temperature properties, including an air mixture with

C

2

F

4

vapor injected from a polytetrafluoroethylene nozzle, for application as an arc-quenching medium in a high-voltage circuit breaker equipped with a nozzle. Chemical composition results for the reaction products at 300–3000 K show that the admixture of

C

2

F

4

vapor causes a decrease in the molar number of

O

2

contained in the air, owing to the production of O-containing compounds such as

C

O

2

and

C
O

. Additionally, the results reveal that the admixture of

C

2

F

4

vapor lead to the production of

C

F

4

as the predominant F-containing compound. Furthermore, the boundary condition for

O

2

production in terms of

O

2

molar number

X

O

2

and

C

2

F

4

molar number

X

C

2

F

4

is formulated. Such evaluation of the mixture composition enables the determination of a reduced effective collision ionization coefficient

α
ˉ

/

N

and a critical reduced electric field strength

E

c
r

/

N

, resulting in

α
ˉ

/

N

= 0. The strength

E

c
r

/

N

for the mixture with 30%–100%

C

2

F

4

molar fraction rises to approximately 150 Td (1 Td = 1

×

10

−
21

V m2) over 300–3000 K, which is 20–50 Td higher than that for high-temperature air unmixed with

C

2

F

4

vapor. The variation in

E

c
r

/

N

is discussed in terms of predominant electron impact processes and the electron energy distribution function in the mixture.
Visible proton Bragg curve imaging by colour centre photoluminescence in radiation detectors based on lithium fluoride films on silica
Authors: Montereali R M , Nigro V , Piccinini M , Vincenti M A , Nenzi P , Ronsivalle C , Nichelatti E 
Published: February 2024

Abstract
Passive solid-state radiation detectors, based on the visible photoluminescence (PL) of radiation-induced colour centres in optically transparent lithium fluoride (LiF), polycrystalline thin films are under investigation for proton beam advanced diagnostics. After proton exposure, the latent images stored in LiF as local formations of stable F2 and F3
+ aggregate defects, are directly read with a fluorescence microscope under illumination in the blue spectral range. Adopting a suitable irradiation geometry, the energy density that protons deposit in the material can be recorded as a spatial distribution of these light-emitting defects, from which a luminous replica of the proton Bragg curve can be thereafter extracted and analysed to reconstruct the proton beam energy spectrum. Their peculiar properties, such as wide dynamic range and linearity of the spectrally-integrated PL response vs. dose, make the investigation of two-dimensional LiF film radiation detectors grown on several types of substrate highly attractive. Here, the case of a LiF thin film thermally evaporated on a silica substrate, irradiated at grazing incidence with a 35 MeV proton beam, is investigated and reported for the first time. A comparison of the measured photoluminescent Bragg curve with Monte Carlo simulations demonstrates that the Bragg peak in the film is located at the very same position that would be expected in the underlying silica substrate rather than in LiF. The film packing density is shown not to have a significant effect on the peak depth, while even small nonzero grazing angle of the impinging proton beam is able to significantly modify the shape of the Bragg curve. These findings are ascribed to the effects of multiple Coulomb scattering in both the film and the substrate and are interesting for proton beam diagnostics and dosimetry.
The fluctuated structural/electronic properties of SrTiO3 two-dimensional materials caused by surface effects
Authors: Yang Tingkai , Yang Chao 
Published: February 2024

Abstract
Perovskite oxide thin films have many astonishing properties, such as multiferroicity, superconductivity, strong correlation, etc, and are closely related to orientations with different symmetry and structural characteristics. Recently, perovskite oxide films with only one unit cell thickness have been synthesized successfully (Ji et al 2019 Nature
570 87–90). Here we investigated the structure and electronic properties of SrTiO3 (STO) two-dimensional (2D) materials with (001), (110), and (111) surfaces. We found that due to surface effects caused atomic distortion fluctuations, the lattice constant and thickness of STO 2D materials with the (110) surface fluctuate sharply with the increase of atomic layers. The band gap of STO 2D materials exhibits oscillation as the number of atomic layers increases, due to the different atomic distortion and surface reconstruction with odd and even atomic layers. The STO 2D materials along (001) surfaces with different atomic layers are always semiconductors. As the atomic layers increasing, the electronic structure of STO 2D materials with (110) or (111) surfaces continuously transitioning between semiconductor and metallic phases, and finally totally become metallic phases, which is closely related to the surface reconstruction effect. The differences between STO 2D materials along the (001) and (110) or (111) surfaces are significant and can be explained by mixed Sr-d, Ti-d, and O-p orbitals. Our studies may provide new insights into the surface effects of perovskite oxide 2D materials.