bluuebunny/crossref_metadata_2025 huggingface dataset:
Dynamics of finite-size air filaments in a static liquid
Authors: Osama Muhammad , Deng Peng , Thoraval Marie-Jean , Agbaglah G. Gilou
Published: May 2022

This study undertakes a numerical investigation of the dynamics of a finite-size air filament surrounded by a denser fluid medium with a range of viscosity. The two edges of the filament retract due to its surface tension effects. It is shown that if the aspect ratio is small, the filament recoils in a single bubble while for large aspect ratios, the filament ruptures at its two ends. Between these two limits, the filament can escape from pinch-off through the reopening of the neck and/or breakup in the middle region. The air filament pinch-off is accompanied by the formation of a thin air thread, which subsequently breaks up into microbubbles. Viscous effects of the external fluid do not show a significant impact on the fate of large or small aspect ratio filaments but instead control the shape of the bulge and the neck region close to breakup. Before breakup, the bulge adopts a prolate shape for Ohnesorge numbers smaller than 0.01, while an oblate shape is obtained for Ohnesorge numbers larger than 1. A spherical shape is obtained between these two limits. For small Ohnesorge numbers, the neck region exhibits a reflection symmetry perpendicular to the filament axis while for large Ohnesorge numbers, a thread of air forms and connects the bulge to the filament. The radius of the neck is shown to decrease as a power-law function of the time before breakup with the exponent of 0.5 for small Ohnesorge numbers and 1 for large Ohnesorge numbers.
Adsorption of C2–C5 alcohols on ice: A grand canonical Monte Carlo simulation study
Authors: Joliat Julien , Picaud Sylvain , Patt Antoine , Jedlovszky Pal
Published: May 2022

In this paper, we report grand canonical Monte Carlo simulations performed to characterize the adsorption of four linear alcohol molecules, comprising between two and five carbon atoms (namely, ethanol, n-propanol, n-butanol, and n-pentanol) on crystalline ice in a temperature range typical of the Earth’s troposphere. The adsorption details analyzed at 228 K show that, at low coverage of the ice surface, the polar head of the adsorbed molecules tends to optimize its hydrogen bonding with the surrounding water, whereas the aliphatic chain lies more or less parallel to the ice surface. With increasing coverage, the lateral interactions between the adsorbed alcohol molecules lead to the reorientation of the aliphatic chains that tend to become perpendicular to the surface; the adsorbed molecules pointing thus their terminal methyl group up to the gas phase. When compared to the experimental data, the simulated and measured isotherms show a very good agreement, although a small temperature shift between simulations and experiments could be inferred from simulations at various temperatures. In addition, this agreement appears to be better for ethanol and n-propanol than for n-butanol and n-pentanol, especially at the highest pressures investigated, pointing to a possible slight underestimation of the lateral interactions between the largest alcohol molecules by the interaction potential model used. Nevertheless, the global accuracy of the approach used, as tested under tropospheric conditions, opens the way for its use in modeling studies also relevant to another (e.g., astrophysical) context.
Pressure-induced magnetic transformations in Cd3As2+MnAs hybrid composite
Authors: Arslanov T. R. , Saypulaeva L. A. , Alibekov A. G. , Zhao X. F. , Ril A. I. , Marenkin S. F.
Published: May 2022

Considerable interest to magnetism of MnAs both in bulk or in the form of epitaxial films is stimulated by its applications as a magnetocaloric material and in spintronic devices. Since the MnAs films deposited on GaAs reproduce well a magnetic transformation related to α–β magnetostructural transition that occurs in bulk MnAs, this first-order phase transition occurs through a phase coexistence over a wide temperature range. Here, we considered the same magnetostructural transition in a bulk hybrid structure based on micrometer-scaled MnAs inclusions embedded into the Cd3As2 matrix. In particular, the effect of high pressure and magnetic fields on the ferromagnetic transition temperature, TC, in a composite Cd3As2 + 30 mol. % MnAs has been studied. We found that at ambient pressure, the transition from α-MnAs to β-MnAs is accompanied by the absence of thermal hysteresis of magnetization, implying a phase coexistence regime. The hysteresis width does not markedly increase even at pressures about P = 0.35 GPa, and displacement of TC occurs with a rate of dTC/dP ∼ −91.42 K/GPa. In the temperature region of the α–β phase coexistence, a local peak at T = 283 K and P = 1 GPa is observed, which is associated with an antiferromagnetic order of MnAs inclusions. Direct measurements of isothermal magnetization vs pressure indicate both the stabilization of the ferromagnetic hexagonal α phase at P < Pmax and the development of an orthorhombic antiferromagnetic long-range order, which propagate up to 5 GPa.
Transition now? Another coup d’état in Burkina Faso
Authors: Engels Bettina
Published: May 2022

The briefing explores the dynamics underpinning the coup d’état in Burkina Faso that took place on 24 to 25 January 2022. It does so by discussing the putschists’ justification to fight threats by non-state armed groups and situates the coup in the history of Burkina Faso. Since formal independence the country has been characterised by strikes, military coups and constitutional referendums. In contrast to 2015, however, when broad popular resistance forced a group of military putschists out of office after only a few days, the trade unions and mass organisations this time do not mobilise active resistance, though in principle they oppose military coups. The briefing raises questions regarding whether the ‘transition phase’ will deliver any substantial change, what might be seen as legitimate forms of regime change, and what the character of political authority is in Burkina Faso, how it might be delivered and by whom.
Matrix reboot: IL-17 signals CAFs to create a second tumor T cell checkpoint
Authors: McGeachy Mandy J.
Published: May 2022

Excessive collagen deposition by fibroblasts surrounding some tumors has seriously limited the efficacy of checkpoint inhibitor therapies. Chen et al. (2022. J. Exp. Med.https://doi.org/10.1084/jem.20210693) show that IL-17 promotes collagen deposition by cancer-associated fibroblasts, enhancing immune exclusion of tumors, and that targeting IL-17–triggered HIF1α expression can reverse matrix mediated immune exclusion.
Biophysical physiology of phosphoinositide rapid dynamics and regulation in living cells
Authors: Jensen Jill B. , Falkenburger Bjoern H. , Dickson Eamonn J. , de la Cruz Lizbeth , Dai Gucan , Myeong Jongyun , Jung Seung-Ryoung , Kruse Martin , Vivas Oscar , Suh Byung-Chang , Hille Bertil
Published: May 2022

Phosphoinositide membrane lipids are ubiquitous low-abundance signaling molecules. They direct many physiological processes that involve ion channels, membrane identification, fusion of membrane vesicles, and vesicular endocytosis. Pools of these lipids are continually broken down and refilled in living cells, and the rates of some of these reactions are strongly accelerated by physiological stimuli. Recent biophysical experiments described here measure and model the kinetics and regulation of these lipid signals in intact cells. Rapid on-line monitoring of phosphoinositide metabolism is made possible by optical tools and electrophysiology. The experiments reviewed here reveal that as for other cellular second messengers, the dynamic turnover and lifetimes of membrane phosphoinositides are measured in seconds, controlling and timing rapid physiological responses, and the signaling is under strong metabolic regulation. The underlying mechanisms of this metabolic regulation remain questions for the future.
Structural determinants of acid-sensing ion channel potentiation by single chain lipids
Authors: Klipp Robert C. , Bankston John R.
Published: May 2022

Acid-sensing ion channels (ASICs) are sensitized to activation by inflammatory mediators such as the polyunsaturated fatty acid (PUFA) arachidonic acid (AA). Previous work has shown that AA can potentiate ASIC currents at subsaturating proton concentrations, but the structural mechanisms of this change in gating are not understood. Here we show that PUFAs cause multiple gating changes in ASIC3, including shifting the pH dependence of activation, slowing the rate of desensitization, and increasing the current even at a saturating pH. The impact on gating depends on the nature of both the head and tail of the lipid, with the head group structure primarily determining the magnitude of the effect on the channel. An N-acyl amino acid (NAAA), arachidonyl glycine (AG), is such a strong regulator that it can act as a ligand at neutral pH. Mutation of an arginine in the outer segment of TM1 (R64) eliminated the effect of docosahexaenoic acid (DHA) even at high concentrations, suggesting a potential interaction site for the lipid on the channel. Our results suggest a model in which PUFAs bind to ASICs via both their tail group and an electrostatic interaction between the negatively charged PUFA head group and the positively charged arginine side chain. These data provide the first look at the structural features of lipids that are important for modulating ASICs and suggest a potential binding site for PUFAs on the channel.
Convergence study and regularizing property of a modified Robin–Robin method for the Cauchy problem in linear elasticity
Authors: Ellabib Abdellatif , Nachaoui Abdeljalil , Ousaadane Abdessamad
Published: May 2022

In this paper, we are interested in solving a Cauchy inverse problem in linear elasticity. For this, we propose a new method based on Robin conditions on the inaccessible boundary, then we study the convergence and regularizing property of the proposed algorithm. We use the finite element method for the discretization of our problem. Further, we treat the spectrum analysis of the discrete problem in order to study the convergence behavior of the proposed method in the discrete case. Finally, we present numerical results which show the efficiency and stability of the proposed approach in the presence of perturbed data. The robustness of the proposed algorithm is also performed for the anisotropic and heterogeneous cases.
Slow light in topological coupled-corner-state waveguide
Authors: Liu Lei , Wang Yueke , Li Mingxing , Zheng Feixiang , Zhou Haiquan
Published: May 2022

We theoretically propose a uide (CCSW), which is composed of a zigzag edge-like structure based on C-4 symmetrical lattice. CCSW mode is achieved by weak coupling between a sequence of higher order topological corner state (TCS). Based on the tight-binding approximation, the flat dispersion relation of CCSW mode is obtained, and suitable for slowing down light. The characteristics of slow light, including the group index, group velocity dispersion, normalized bandwidth and normalized delay-bandwidth product, are discussed in detail. At the Eigen frequency of individual TCS, the group velocity dispersion of CCSW mode is zero. Importantly, the CCSW mode shows strong robustness when introducing disorders, compared with the conventional Coupled-Resonator-Optical Waveguide based on photonic crystal defect cavities. Our findings may find topological slow light applications such as optical buffers, the processing of optical signals, optical delay lines and so on.
Distribution characteristics for initial time delay of streamer of shielding spheres under operating impulse voltage at high altitudes
Authors: Geng Jianghai , Cheng Yuzhou , Wang Ping , Lü Fangcheng , Ding Yujian , Yao Xiuyuan , Jiang Ling
Published: May 2022

With continuous promotion of construction of ultra high voltage DC projects in high-altitude areas, it is of important theoretical and practical engineering significance to study long gap discharge characteristics at high altitudes. As the initial and key stage for development of long air gap discharge, the initial stage of streamer reflects the randomness of long gap discharge to a certain extent, and time delay characteristics are important indicators to reflect the randomness. In this paper, we build a photoelectric detection system based on the photomultiplier tube and photoelectric integrated sensor, carry out an operating impulse discharge test of long gap of the shielding sphere-plate with different diameters at altitudes of 50 m and 2200 m respectively, obtain the space field strength, optical power, discharge current and voltage of the whole process of discharge development, and analyze the characteristics of boost time delay and statistical time delay of streamer based on the photoionization model and Weibull Distribution model. According to study results, the average value

T
‾

and dispersibility of initial time delay of streamer increase with the increase of altitude and electrode diameter; the boost time delay t
0 of streamer decreases with increase of altitude and increases with increase of electrode size; the statistical time delay t
s of streamer can properly comply with Weibull distribution, and its characteristic parameter has a clear physical meaning. The dispersibility of statistical time delay will increase with altitude and electrode size, and compared with electrode size, altitude has a greater impact on the dispersibility of statistical time delay. The study results of this paper have important guiding value for selection and optimization on clear distance of the valve hall of a converter station in high altitude areas.
Co-deposition of MoS2 films by reactive sputtering and formation of tree-like structures
Authors: Kim Myeongok , Giteau Maxime , Ahsan Nazmul , Miyashita Naoya , Thirumalaisamy Logu , Chen Chen , Redwing Joan M , Okada Yoshitaka
Published: May 2022

Transition metal dichalcogenides are versatile layered materials with potential applications ranging from optoelectronic devices to water splitting. Top-down fabrication methods such as exfoliation are not practical for a large-scale production of high-quality devices: a bottom-up approach such as sputtering, a low-temperature deposition method, is more suitable. However, due to its anisotropic nature, the growth mechanism of molybdenum disulfide (MoS2) via sputtering is complex and remains to be investigated in detail. In this paper, we study the growth of MoS2 films co-deposited by using a sulfur (S) hot-lip cell and a molybdenum (Mo) sputtering target via reactive sputtering. The impact of S partial pressure on the structure and morphology of MoS2 films was systematically characterized, and it was observed that the growth is dominated by vertically-oriented sheets with horizontal branches, resulting in a tree-like structure. The growth front of the structures is ascribed to the anisotropic incorporation of adatoms with regards to the orientation of MoS2.
Interfacial electronic properties of metal/CsSnBr3 heterojunctions
Authors: Li Jing , Guo Xinwei , Cai Bo , Hu Yang , Liu Gaoyu , Guo Tingting , Song Xiufeng , Zeng Haibo , Zhang Shengli
Published: May 2022

All-inorganic lead-free perovskite CsSnBr3, has been proved good stability and optoelectronic properties in theory and experiment. However, the interfacial electronic properties of metal/CsSnBr3 are still unclear in electronic devices. Herein, we systematically investigate the interfacial properties of metal electrodes (Al, Ag and Au) and CsSnBr3 with different atomic terminals (SnBr2-T and CsBr-T) through the first-principles calculation. SnBr2-T and CsBr-T have various contact types and Schottky barriers due to their different interaction strengths with metals. In particular, the moderate interlayer coupling strength with Al leads to the ultra-low Schottky barrier and tunneling barrier, which makes Al possess the best contact performance among the studied metals. Furthermore, the external electric field can be effective in regulating the Schottky barrier and realizing the Ohmic contact. These findings provide useful guidance for the design of perovskite-based nanoelectronic devices with high performance.
The quantum confinement effects on the electronic properties of monolayer GeS nanoribbon with tube-edged reconstruction
Authors: Kong Weizheng , Zhang Yanxue , Jiang Xue , Su Yan , Liu Hongsheng , Gao Junfeng
Published: May 2022

Monolayer α-phase GeS is promising for many novel applications due to its high carrier mobility and suitable band gap. Recently, the metal and nonmetal zigzag edges of monolayer α-phase GeS have been predicted to undergo universal ZZ(Ge-Tube)/ZZ(S-R) edge reconstruction. Therefore, studies on GeSNR should be reconsidered. In this paper, we study the quantum confinement effects on the electronic properties of edge reconstructed monolayer GeS nanoribbon (GeSNR) by using first-principles calculations. As width of the nanoribbon increases from 10 to 41 Å, the band gap keeps indirect and linearly decreases from 1.57 to 0.87 eV. Robust spatial separation of valence band maximum and conduction band minimum exist in reconstructed GeSNR with width larger than 19 Å. Moreover, high carrier mobility is expected in the reconstructed GeSNR. Our results suggest that reconstructed GeS nanoribbon is an important candidate for optoelectronics and photocatalytic.
Time evolution of neutral and charged species in Ar/C2H2 capacitively-coupled RF discharges
Authors: Jiménez-Redondo Miguel , Tanarro Isabel , Herrero Víctor J
Published: May 2022

The first stages of polymerization in plasmas of Ar/C2H2 have been studied both experimentally and using a kinetic model, by following the time evolution of the main neutral and ionic species in the discharge. The abundances of the different neutrals and ions have been measured by quadrupole mass spectrometry in conditions specifically chosen to avoid dust formation in the plasma. Maxima occurring at different times from the ignition of the discharge were detected for the density of the neutral species sampled, generally consistent with a stepwise polymerization mechanism. Ions were found to fundamentally follow the trend of their neutral counterparts, with the time evolution for negative ions stressing the difference in the chemical mechanisms responsible for the formation of the two primitive anions, C2H− and H2CC−. Positive and negative ion distributions were measured in the steady state of the discharge. Detection of anions with up to 22 carbon atoms was possible in mixtures with high acetylene content. A volume averaged kinetic model with a simple description of the Ar/C2H2 chemistry was used to identify the main reaction pathways and was able to satisfactory reproduce the experimental results.
Exploring the potential structural, optical, dielectric facets and in-vitro behavior of combeite synthesized by the sol-gel route
Authors: Kolli Nishant Kumar , Kanikaram Sai Phalguna , Rai Krisanta , Kundu Swarup , Roy Santanu
Published: May 2022

The current study combeite (Na2Ca2Si3O9) was synthesized by the sol-gel route and an attempt was made to investigate its various features. The formation of a pure phase was confirmed using the powder x-ray diffraction technique. Dielectric measurements were performed on the synthesized material over a wide range of temperature and frequency. The optical band gaps were found to be in the range 1.5–2.8 eV. The in-vitro acellular immersion studies showed the formation of apatite on the surface of combeite. The cell proliferation assay indicated enhanced cell viability in the case of combeite when compared to calcium phosphate. These results of this study have implications for various industrial and medical applications.
Relativistic Hartree–Fock model and its recent progress on the description of nuclear structure
*
Authors: Long W H , Geng J , Liu J , Wang Z H
Published: May 2022

Regarding the stage progress on the relativistic Hartree–Fock (RHF) model achieved recently, we review the extensive developments of the model itself, including the descriptions of axially deformed unstable nuclei and nuclear spin-isospin excitations, which shows that a complete RHF framework is now available for exploring the tensor force effects in both ground state and excited states of unstable nuclei. Meanwhile, the recent RHF descriptions of the pseudo-spin symmetry restoration and the new magicity are also reviewed. It shows that the Fock terms, particularly the

ρ

-tensor coupling and naturally introduced tensor force components, bring about significant improvements in maintaining the delicate in-medium balance of nuclear attractions and repulsions, and uniformly interpreting the emergence of new magicity in 52,54Ca. The revealed microscopic mechanisms not only deepen our understanding on the properties of nuclear structure, but also help to guide the further development of the effective nuclear force.
Thermally enhanced photoluminescence and temperature sensing properties of Sc2W3O12:Eu3+ phosphors
Authors: Niu Yu-De , Wang Yu-Zhen , Zhu Kai-Ming , Ye Wang-Gui , Feng Zhe , Liu Hui , Yi Xin , Wang Yi-Huan , Yuan Xuan-Yi
Published: May 2022

Recently, lanthanide-ion-doped luminescent materials have been extensively used as optical thermometry probes due to their fast responses, non-contact, and high sensitivity properties. Based on different responses of two emissions to temperature, the fluorescence intensity ratio (FIR) technique can be used to estimate the sensitivities for assessing the optical thermometry performances. In this study, we introduce different doping concentrations of Eu3+ ions into negative thermal expansion material Sc2W3O12 to increase the thermal-enhanced luminescence from 373 K to 548 K, and investigate the temperature sensing properties in detail. All samples can exhibit their good luminescence behaviors thermally enhanced. The emission intensity of Sc2W3O12:6-mol% Eu3+ phosphor reaches 147.8% of initial intensity at 473 K. As the Eu3+ doping concentration increases, the resistance of the sample to thermal quenching decreases. The FIR technique based on each of the transitions 5D→ 7F1 (592 nm) and 5D→ 7F2 (613 nm) of Eu3+ ions demonstrates a maximum relative temperature sensitivity of 3.063% K−1 at 298 K for Sc2W3O12:6-mol% Eu3+ phosphor. The sensitivity of sample decreases with the increase of Eu3+ concentration. Benefiting from the thermal-enhanced luminescence performance and good temperature sensing properties, the Sc2W3O12:Eu3+ phosphors can be used as optical thermometers.
Two-dimensional Sb cluster superlattice on Si substrate fabricated by a two-step method
Authors: Zhang Runxiao , Liu Zi , Hu Xin , Xie Kun , Li Xinyue , Xia Yumin , Qin Shengyong
Published: May 2022

Nanoclusters consisting of a few atoms have attracted a lot of research interests due to their exotic size-dependent properties. Here, well-ordered two-dimensional Sb cluster superlattice was fabricated on Si substrate by a two-step method and characterized by scanning tunneling microscopy. High resolution scanning tunneling microscope measurements revealed the fine structures of the Sb clusters, which consist of several Sb atoms ranging from 2 to 7. Furthermore, the electronic structure of the nanocluster displays the quantized energy-level which is due to the single-electron tunneling effects. We believe that the fabrication of Sb cluster superlattice broadens the species of the cluster superlattice and provides a promising candidate to further explore the novel physical and chemical properties of the semimetal nanocluster.
Pulsar Survey With the QiTai 110 m Radio Telescope
Authors: Xie Jin-Tao , Wang Jing-Bo , Wang Na , Hu Yue
Published: May 2022

With a collecting area of 9400 m2, the Xinjiang QiTai 110 m radio Telescope (QTT) will allow for a significant advance in the search and observation of pulsars. We have updated the galactic electron density model, scattering model, spectral distribution, and radial distribution of PsrPopPy to generate the population of isolate radio pulsars in the Galaxy. The spiral arm, including the local spiral arm, is considered when generating pulsar locations. By simulation, we estimate the number of previously undetected radio pulsars that QTT will discover with its possible receivers for different strategies. Using the PAF receiver, 2200 previously unknown pulsars could be discovered in 43 days. The 96-beam PAF receiver can produce ∼10.56 GB of data per second.
Correlation between Brightness Variability and Spectral Index Variability for Fermi Blazars
Authors: Yang Wen-Xin , Xiao Hu-Bing , Wang Hong-Guang , Yang Jiang-He , Pei Zhi-Yuan , Wu De-Xiang , Yuan Yu-Hai , Fan Jun-Hui
Published: May 2022

In this work, the γ-ray photon flux, photon spectral index (α
ph), variability index (

log

V
.
I
.

), and the synchrotron peak frequency (

log

ν

p

) are compiled for 851 common blazars from the 3FGL and 4FGL catalogs and Fan et al. to investigate variability properties for Fermi blazars. Our calculations and analyses reach following results: (1) the averaged luminosity, spectral index, and variability index of FSRQs are higher than those of BL Lacs for the whole sample. (2) It is found that the spectral index variation is closely anti-correlated with the luminosity variation implying that the spectrum becomes harder when the source becomes brighter in the γ-ray band. (3) Positive correlations are found between the photon spectral index and both γ-ray luminosity and variability index (

log

V
.
I
.

) for the whole sample, but anti-correlations are found in the two correlations for FSRQs. For BL Lac subclass, there is a marginal anti-correlation between the photon spectral index and both γ-ray luminosity, and a positive correlation between the photon spectral index and the variability index (

log

V
.
I
.

). We think those two positive correlations found for the whole sample are apparent. (4) We adopted the SVM machine learning method to separate BL Lacs and FSRQs in the

α

ph

versus

log

L

γ

and

α

ph

versus

log

V
.
I
.

plots and proposed that a BCU is an FSRQ candidate if it satisfies

log

V
.
I
.

>

−
10.119
α
+
24.855

, or

α

ph

>
−
0.048

log

L

γ

+
4.498

, otherwise, it is a BL Lac candidate. Our classification results are quite consistent with those by Kang et al (2019).
Probing the Progenitor of High-z Short-duration GRB 201221D and its Possible Bulk Acceleration in Prompt Emission
Authors: Yuan Hao-Yu , Lü Hou-Jun , Li Ye , Zhang Bin-Bin , Sun Hui , Rice Jared , Yang Jun , Liang En-Wei
Published: May 2022

The growing observed evidence shows that the long- and short-duration gamma-ray bursts (GRBs) originate from massive star core-collapse and the merger of compact stars, respectively. GRB 201221D is a short-duration GRB lasting ∼0.1 s without extended emission at high redshift z = 1.046. By analyzing data observed with the Swift/BAT and Fermi/GBM, we find that a cutoff power-law model can adequately fit the spectrum with a soft

E

p

=

113

−
7

+
9

keV, and isotropic energy

E

γ
,
iso

=

1.36

−
0.14

+
0.17

×

10

51

erg

. In order to reveal the possible physical origin of GRB 201221D, we adopted multi-wavelength criteria (e.g., Amati relation, ε-parameter, amplitude parameter, local event rate density, luminosity function, and properties of the host galaxy), and find that most of the observations of GRB 201221D favor a compact star merger origin. Moreover, we find that

α

ˆ

is larger than

2
+

β

ˆ

in the prompt emission phase which suggests that the emission region is possibly undergoing acceleration during the prompt emission phase with a Poynting-flux-dominated jet.
Comparison of the Coronal Green-line Intensities with the EUV Measurements from SDO/AIA
Authors: Zhang Xue-Fei , Liu Yu , Zhao Ming-Yu , Liu Ji-Hong , Elmhamdi Abouazza , Song Teng-Fei , Li Zi-Han , Li Hong-Bo , Sha Fei-Yang , Wang Jing-Xing , Li Xiao-Bo , Shen Yuan-Deng , Liu Shun-Qing , Liang Hong-Fei , Al-Shammari R. M.
Published: May 2022

The intensity of the green line (Fe xiv 5303 Å) is the strongest in the visible spectrum of the solar corona, and this line has been used as long-term powerful diagnostic tools for studying the coronal configurations and hot plasma dynamics. However, it remains unclear and an open question whether there exists close relationship between the green line intensities and the coronal extreme ultraviolet (EUV) line emissions for various coronal structures. In this paper, we use the green-line data by the Lijiang YOGIS Lyot coronagraph and the EUV data from the Solar Dynamics Observatory/Atmospheric Imaging Assembly instruments in order to perform direct comparisons and analyses, based on two algorithms developed to extract particular features in the low corona. It is found that, among the correlation coefficients obtained between the intensities of 5303 Å and the EUV lines, the coefficients between the green line and the 211 Å wavelength for different coronal structures and different limb locations always keep the highest values (ranging from 0.89 to 0.99), which has not been reported before. This result can be helpful and promising to link together the various physical processes involved at different heights in the corona by precisely tracking the bright loops or other features observed in 5303 Å above the limb down to the correct surface locations revealed by the 211 Å data. Furthermore, the ground-based observations of the coronal green line and the space-based EUV observations at 211 Å can advantageously complement each other when there is a need.
The Physical Properties and Starspot Activity of the Triple System KIC 6525196
Authors: Pan Yang , Fu Jian-Ning , Zhang Xiao-Bin , Wang Jia-Xin , Li Chun-Qian
Published: May 2022

We present the results of photometric and spectroscopic analyses for the triple-lined system KIC 6525196, an eclipsing binary accompanied by a third star. By modeling the Kepler light curves and radial velocities from LAMOST and HIDES observations, absolute parameters of the system are determined. Both components of the eclipsing binary are found to be solar-like stars with masses and radii of M
1 = 1.0286 ± 0.0026 M
⊙, R
1 = 1.127 ± 0.008 R
⊙, and M
2 = 0.9667 ± 0.0024 M
⊙, R
2 = 0.963 ± 0.007 R
⊙. The mass of the third star is determined to be M
3 = 0.772 ± 0.010 M
⊙. With the out-of-eclipse light residuals, we measure rotation period and decay timescale of an active region by using the autocorrelation function. In comparison to the Sun, the activity level of the system is significantly stronger. In addition, a possible short photometric activity cycle of ∼244 days is detected.
Initial results from boron powder injection experiments in WEST lower single null L-mode plasmas
Authors: Bodner G. , Gallo A. , Diallo A. , Lunsford R. , Moreau Ph. , Nagy A. , Pellissier F.-P. , Guillemaut C. , Gunn J.P. , Bourdelle C. , Desgranges C. , Manas P. , Bortolon A. , Klepper C.C. , Tsitrone E. , Unterberg E.A. , Vermare L. , the WEST Team
Published: May 2022

Using a recently installed impurity powder dropper (IPD), boron powder (<150 μm) was injected into lower single null (LSN) L-mode discharges in WEST. IPDs possibly enable real-time wall conditioning of the plasma-facing components and may help to facilitate H-mode access in the full-tungsten environment of WEST. The discharges in this experiment featured I
p = 0.5 MA, B
T = 3.7 T, q
95 = 4.3, t
pulse = 12–30 s, n
e,0 ∼ 4 × 1019 m−2, and P
LHCD ∼ 4.5 MW. Estimates of the deuterium and impurity particle fluxes, derived from a combination of visible spectroscopy measurements and their corresponding S/XB coefficients, showed decreases of ∼50% in O+, N+, and C+ populations during powder injection and a moderate reduction of these low-Z impurities (∼50%) and W (∼10%) in the discharges that followed powder injection. Along with the improved wall conditions, WEST discharges with B powder injection observed improved confinement, as the stored energy W
MHD, neutron rate, and electron temperature T
e increased significantly (10%–25% for W
MHD and 60%–200% for the neutron rate) at constant input power. These increases in confinement scale up with the powder drop rate and are likely due to the suppression of ion temperature gradient (ITG) turbulence from changes in Z
eff and/or modifications to the electron density profile.
Erratum: The open XXZ chain at Δ = −1/2 and the boundary quantum Knizhnik–Zamolodchikov equations (2021 J. Stat. Mech.
013104)
Authors: Hagendorf Christian , Liénardy Jean
Published: May 2022

The open XXZ spin chain with the anisotropy parameter

Δ
=
−

1

2

and diagonal boundary magnetic fields that depend on a parameter x are studied. For real x > 0, the exact finite-size ground-state eigenvalue of the spin-chain Hamiltonian is explicitly computed. In a suitable normalisation, the ground-state components are characterised as polynomials in x with integer coefficients. Linear sum rules and special components of this eigenvector are explicitly computed in terms of determinant formulas. These results follow from the construction of a contour-integral solution to the boundary quantum Knizhnik–Zamolodchikov equations associated with the R-matrix and diagonal K-matrices of the six-vertex model. A relation between this solution and a weighted enumeration of totally-symmetric alternating sign matrices is conjectured.
Optimization of pixel size and propagation distance in X-ray phase-contrast virtual histology
Authors: Donato S. , Arana Peña L.M. , Bonazza D. , Formoso V. , Longo R. , Tromba G. , Brombal L.
Published: May 2022

X-ray phase-contrast coupled to high-spatial resolution imaging systems provides a high sensitivity for distinguishing soft tissue structures in small samples, thus being suited for X-ray virtual histology. Propagation-based phase-contrast tomography can deliver a considerable gain in signal-to-noise ratio (SNR) at small pixel sizes when it is combined to a suitable phase retrieval filter. We optimized acquisition parameters, namely the propagation distance and the pixel size, with the aim of providing adequate spatial resolution and sensitivity for virtual histology of breast surgery specimens, scanned with a phase-contrast microtomography (μCT) system employing a commercial sCMOS detector at the SYRMEP beamline of the Italian synchrotron facility Elettra (Trieste, Italy). A pathological breast tissue sample was embedded in paraffin and imaged using a polychromatic synchrotron beam at an average energy of 24 keV. The high numerical optical aperture of the imaging system enabled to adjust the pixel size to 1, 2.5 and 4 μm. The scans were acquired at five sample-to-detector distances: 4.5, 150, 250, 500 and 1000 mm. SNR was measured in an homogeneous region portion of the μCT image for each combination of pixel size and propagation distance. Experimental results were compared to a theoretical model taking into account the actual point spread function of the employed imaging system. The measured gain of SNR associated with the application of the phase-retrieval matched the predictions for large Fresnel numbers (N
F > 2). For each pixel size, an optimal range of propagation distances was found. Optimal μCT reconstructions were then compared with their respective histopatological images, showing an excellent visibility of relevant structures. The optimization performed in this study will allow to select the most appropriate geometrical configurations for future acquisitions of virtual histology images of different specimens via phase-contrast microtomography.
Investigation of structures in tunnel overburdens by means of muon radiography
Authors: Li J. , Li Z. , Han R. , Cheng Y. , Mao X. , Yu L. , Feng X. , Liu B. , Jiang L. , Ouyang X.
Published: May 2022

Cosmic ray muon radiography is a new imaging technique that
is being used to investigate the density structure of large objects
and the shallow crust. For example, it has been used to investigate
magma conduits of active volcanoes, cavities above tunnels and
hidden chambers inside pyramids, and has proven to be effective and
accurate. However, low cosmic muon flux has limited the development
of muon radiography in many engineering applications. In this paper,
the potential application of muon radiography to investigate density
anomalies in tunnel overburden is discussed. Results show that in a
typical 25-meter thick overburden, muon radiography can identify
overburden anomalies of 10% in two hours with an inaccuracy
probability of 30.8% by lack of enough statistics, and this
inaccuracy will reduce to 2.2% if data are collected over a full
day. The study also indicates that muon radiography can detect
structure density anomalies above 1% with an inaccuracy probability
of 2.2%. As a non-destructive, non-invasive and passive imaging
method, cosmic ray muon radiography has its great potential in
timely monitoring and imaging of overburden structures to discover
potential structural defects.
Effect of immunization through vaccination on the SIS epidemic spreading model
Authors: Tomé Tânia , de Oliveira Mário J
Published: May 2022

We analyze the susceptible–infected–susceptible model for epidemic spreading in which a fraction of the individuals become immune by vaccination. This process is understood as a dilution by vaccination, which decreases the fraction of the susceptible individuals. For a nonzero fraction of vaccinated individuals, the model predicts a new state in which the disease spreads but eventually becomes extinct. The new state emerges when the fraction of vaccinated individuals is greater than a critical value. The model predicts that this critical value increases as one increases the infection rate reaching an asymptotic value, which is strictly less than the unity. Above this asymptotic value, the extinction occurs no matter how large the infection rate is.
Aggregation in non-uniform systems with advection and localized source
Authors: Zagidullin R , Smirnov A P , Matveev S , Brilliantov N V , Krapivsky P L
Published: May 2022

We explore analytically and numerically agglomeration driven by advection and localized source. The system is inhomogeneous in one dimension, viz along the direction of advection. It is characterized by the kinetic coefficients—the advection velocity, diffusion coefficient and the reaction kernel, quantifying the aggregation rates. We analyze a simplified model with mass-independent advection velocity, diffusion coefficient, and reaction rates. We also examine a model with mass-dependent coefficients arising in the context of aggregation with sedimentation. For the quasi-stationary case and simplified model, we obtain an exact solution for the spatially dependent agglomerate densities. For the case of mass-dependent coefficients we report a new conservation law and develop a scaling theory for the densities. For the numerical efficiency we exploit the low-rank approximation technique; this dramatically increases the computational speed and allows simulations of very large systems. The numerical results are in excellent agreement with the predictions of our theory.
Tuning weak localization in single-layer disordered SnSe2/graphene/h-BN field-effect device
Authors: Chen Wei-Chen , Chuang Chiashain , Wang Tian-Hsin , Yeh Ching-Chen , Chen Sheng-Zong , Sakanashi Kohei , Kida Michio , Lin Li-Hung , Lee Po-Han , Wu Po-Chen , Wang Sheng-Wen , Watanabe Kenji , Taniguchi Takashi , Hsieh Ya-Ping , Aoki Nobuyuki , Liang Chi-Te
Published: May 2022

We report fabrication and measurements of single-layer SnSe2/chemical vapor deposition (CVD) graphene/hexagonal boron nitride (h-BN) field-effect device. The coherent magnetotransport properties of such a hybrid system are systematically studied so as to obtain a good understanding of the structure which may find potential applications in thermoelectricity, flexible electronics, quantum coherent sensor as well as stress sensing. We observed weak localization well described by the Hikami-Larkin-Nagaoka model and the phase coherence length is around 540 nm for V
BG = −20 V at 1 K. The phase coherence length could be effectively changed by controlling the temperature and gate voltage. We also obtain good field-effect dependent properties of atomic-scale SnSe2 ultrathin film/graphene system. Given the current challenges in tuning single-layer SnSe2/CVD graphene on h-BN with a suitable dielectric layer, our results suggest the potential of quantum coherent effect, an effective way for development of future quantum nano-switch device.
Exfoliation corrosion susceptibility on friction stir welded aluminium 6061/Cr2O3 composite
Authors: Uday K N , Senthilraj K , Rajamurugan G
Published: May 2022

The current study investigates the exfoliation corrosion behavior of friction stir welded aluminum composite. The stir casting method was employed to fabricate chromium oxide (2 and 4% wt) reinforced Al 6061 composites. The fabricated composite samples are friction stir welded with two process parameters. The solution immersion tests were performed for two intervals per the ASTM G34 (24 h, 48 h), and the weight loss method was employed. The corrosion sample is analyzed by optical microscope FESEM and surface roughness. The gelatinous corrosion product formed over the surface can apply pressure over the grains resulting in the formation of pits. The intergranular corrosion (IGC) is formed by continuous penetration of the solution and the pits. The grains suffering from IGC are more susceptible to pit. The weight-loss method is not sufficient to predict the damage induced by the exco solution. Evaluating the pit depth can help to know the severity of corrosion. The measurement of the pit is difficult due to its irregular nature. The surface roughness instrument is used, and the damage is represented in average roughness (Ra) and average depth (Rz). The exposure duration and welding parameters play a significant role in corrosion. More material is lost at higher process parameters and extended hours of the test, forming higher surface deterioration.
Aluminum alloy and galvanized steel CMT weld joints for lightweight automobile applications
Authors: Zope Bhagyashri , Dey Tapobrata , Jatti Vijaykumar S , Sarnobat Sandeep S
Published: May 2022

Cold Metal Transfer (CMT) lap joint of Al6061-T6 and Galvanized steel is studied in this paper using design of experiments method. Welding parameters considered for the work includes stick out distance (10 mm −14 mm), wire-feed speed (3.5 m min−1 – 4 m min−1) and torch angle (10˚ to 15˚). Weld strength is optimized by using Taguchi analysis by optimizing input variables with 100% argon gas and stick out distance of 14 mm and overlap region of 13 mm. Weldments were cut in shape and size as per ASTM E8 to perform uni-axial tensile test. Further ANOVA analysis is used to understand the effect of individual parameters & their contribution on weld strength. Result depicted all three input parameter significantly effects the strength. Experiments showed that Al6061-T6 is possible to be welded with the Galvanized-steel using CMT.
Phasing out coal power plants based on cumulative air pollution impact and equity objectives in net zero energy system transitions
Authors: Mayfield Erin N
Published: May 2022

Transitioning to a net zero economy entails rapidly retiring US coal power plants, a major source of both greenhouse gases and air pollution. Conceptualizations of just transitions often embed climate, socioeconomic, and environmental justice objectives. Here we evaluate the influence of cumulative air pollution impact and equity objectives in the context of coal electric power plant retirement decisions. Operating coal power plants accounted for approximately 11 600 mortalities ($100B in damages) in 2018, disproportionately impacting low income, nonwhite, and rural populations. To evaluate the future phase-out of coal generators, we optimize for alternative climate policy goals, in addition to air pollution objectives related to the distribution of impacts on the basis of income, race, voting patterns, population density, and National Ambient Air Quality Standards classifications. With policy goals to both achieve net zero emissions by mid-century and to minimize cumulative air pollution-related mortality, approximately 134 000 deaths ($1.2T) are avoided from 2020 to 2050 (relative to business-as-usual). We find that the way in which equity objectives are operationalized has a large influence on asset-level retirement decisions and policy design. Phase-out strategies associated with policy objectives to minimize cumulative mortalities across the US population are generally consistent with objectives to minimize impacts on vulnerable subpopulations, but differ from those that target geographically-defined vulnerable communities.
An algorithm to recognize regular singular Mahler systems
Authors: Faverjon Colin , Poulet Marina
Published: May 2022

This paper is devoted to the study of the analytic properties of Mahler systems at

0
0

. We give an effective characterisation of Mahler systems that are regular singular at

0
0

, that is, systems which are equivalent to constant ones. Similar characterisations already exist for differential and (

q
q

-)difference systems but they do not apply in the Mahler case. This work fills in the gap by giving an algorithm which decides whether or not a Mahler system is regular singular at

0
0

. In particular, it gives an effective characterisation of Mahler systems to which an analog of Schlesinger’s density theorem applies.
A note on the Erdős-Hajnal hypergraph Ramsey problem
Authors: Mubayi Dhruv , Suk Andrew , Zhu Emily
Published: May 2022

We show that there is an absolute constant

c
>
0

c>0

such that the following holds. For every

n
>
1

n > 1

, there is a 5-uniform hypergraph on at least

2

2

c

n

1

/

4

2^{2^{cn^{1/4}}}

vertices with independence number at most

n
n

, where every set of 6 vertices induces at most 3 edges. The double exponential growth rate for the number of vertices is sharp. By applying a stepping-up lemma established by the first two authors, analogous sharp results are proved for

k
k

-uniform hypergraphs. This answers the penultimate open case of a conjecture in Ramsey theory posed by Erdős and Hajnal in 1972.
Congruences concerning generalized central trinomial coefficients
Authors: Chen Jia-Yu , Wang Chen
Published: May 2022

For any

n
∈

N

=
{
0
,
1
,
2
,
…
}

n\in \mathbb {N}=\{0,1,2,\ldots \}

and

b
,
c
∈

Z

b,c\in \mathbb {Z}

, the generalized central trinomial coefficient

T
n

(
b
,
c
)

T_n(b,c)

denotes the coefficient of

x
n

x^n

in the expansion of

(

x
2

+
b
x
+
c

)
n

(x^2+bx+c)^n

. Let

p
p

be an odd prime. In this paper, we determine the summations

∑

k
=
0

p
−
1

T
k

(
b
,
c

)
2

/

m
k

\sum _{k=0}^{p-1}T_k(b,c)^2/m^k

modulo

p
2

p^2

for integers

m
m

with certain restrictions. As applications, we confirm some conjectural congruences of Sun [Sci. China Math. 57 (2014), pp. 1375–1400].
On intersection and transversality of maps
Authors: Libardi Alice , de Mattos Denise , dos Santos Edivaldo
Published: May 2022

Given a smooth map

f
V

:
V
→
K

f_V\colon V \to K

with

f
V
∗

(

ν
K

)
=

ν
V

f^*_V (\nu _K) = \nu _V

, a general question arises: under which conditions there exists a smooth extension

f
:
M
→
N

f\colon M \to N

of

f
V

f_V

such that

f
f

is transverse to

K
K

and

f

−
1

(
K
)
=
V

f^{-1}(K) = V

, where

M
M

,

N
N

are smooth closed manifolds of dimension

m
m

and

n
n

,

V
V

,

K
K

are closed submanifolds of

M
M

and

N
N

, respectively, of same codimension and

ν
K

\nu _K

,

ν
V

\nu _V

are the normal bundles of

K
K

in

N
N

and

V
V

in

M
M

, respectively. In this paper, we give conditions to the existence of extensions, by using bordism intersection product. Moreover, we present an interesting and non-trivial example illustrating the systematic construction of such extensions, skeletonwise.
Hausdorff dimension of Julia sets of unicritical correspondences
Authors: Siqueira Carlos
Published: May 2022

We show that if

β
>
1

\beta >1

is a rational number and the Julia set

J
J

of the holomorphic correspondence

z

β

+
c

z^{\beta }+c

is a locally eventually onto hyperbolic repeller, then the Hausdorff dimension of

J
J

is bounded from above by the zero of the associated pressure function. As a consequence, we conclude that the Julia set of the correspondence has zero Lebesgue measure for parameters close to zero, whenever

q
2

>
p

q^2>p

and

β
=
p

/

q

\beta =p/q

in lowest terms.