bluuebunny/crossref_metadata_2025_split huggingface dataset:
On the slow ionization waves forming the breakdown in a long capillary tube with helium at low pressure
Authors: Akishev Yuri , Alekseeva Tatyana , Karalnik Vladimir , Petryakov Alexander 
Published: December 2021

Abstract
The results of studies of an electrical breakdown leading to the glow discharge ignition in a long capillary quartz tube are presented. Under such conditions, the breakdown completion is preceded by the development of direct, backward, and counter slow ionization waves (IWs) traveling in the tube. The initiation of the waves was created in helium at low pressure (P = 10 Torr) by the high-voltage pulses of positive and negative polarity with amplitude of several kilovolts. In the beginning, the regime without the breakdown completion in the tube was studied. In this regime, the propagation of only direct positive and direct negative IWs happens. The research on dynamics of the direct, backward, and counter positive and negative waves followed by a complete breakdown was done as well. The influence of the pre-existing plasma on the IWs propagation was also studied. The plasma was created in advance by low-current glow discharge being formed in the tube. The instant images of IWs were correlated with the electrical currents formed by the waves, that is, with the displacement current through the dielectric wall and the conductive current through the plasma column. In the experiments, the fine-sectioned electrode wrapped around the lateral tube surface was used. The usage of such electrode allowed one to study the dynamics of the surface charge deposition and deletion happening during the direct and backward wave propagation, respectively. Finally, a strong difference in the spatial structure and velocity of positive and negative direct waves traveling through non-ionized gas was revealed. Contrary, both the positive and negative backward waves traveling through the plasma formed by previous direct waves have the parameters close to each other.
Temperature-dependent electronic structure of γ-phase CuI: first-principles insights
Authors: Xu Ze-Li , Yang Chang , Wu Yu-Ning 
Published: December 2021

Abstract
To deepen the understanding of CuI that emerges as a promising nextgeneration transparent display material, we investigate the temperature effect on the electronic structures of its room-temperature phase γ-CuI. Using density-functional-theory-based approaches, we investigate the bandgap renormalization, which is contributed by the electron-phonon (elph) interaction and lattice thermal expansion. Different from most semiconductors, the bandgap widens as temperature increases, although it only widens by 88.3 meV from 0 to 600 K. In addition, based on the temperature-dependent band structure and conventional Drude model, we investigate the influences of the effective masses and evaluate the hole mobilities limited by phonon scattering along different directions. The calculated mobilities agree well with existing experimental values. Our study not only provides a fundamental understanding of the temperature effect on the electronic structure of CuI, but also gives insights for further improvement of the electronic and thermoelectric devices based on CuI.
High-resolution RHEED analysis of dynamics of low-temperature superstructure transitions in Ge/Si(001) epitaxial system
Authors: Dirko Vladimir V , Lozovoy Kirill A , Kokhanenko Andrey P , Voitsekhovskii Alexander V 
Published: December 2021

Abstract
In this paper, we analyze superstructural transitions during epitaxial growth of two-dimensional layers and the formation of quantum dots by the Stranski–Krastanov mechanism in elastically stressed systems by the reflection high-energy electron diffraction method. Detailed dependences of the periodicity parameter N of the 2 × N reconstruction on the effective thickness of the deposited material in a wide range of growth temperatures during epitaxy of germanium on a silicon surface with a crystallographic orientation (001) are obtained. Superstructural transitions and the change in the value of the parameter N at low temperatures of epitaxy in this system have been investigated for the first time. It is shown that the length of dimer rows in such a reconstruction during the growth of pure germanium on silicon can reach a value of no less than N = 11. A relationship is found between the value of the parameter N, determined by elastic strains in the system, and the critical thickness of the transition from two-dimensional to three-dimensional growth. Based on this relationship, a physical mechanism is proposed that explains the nature of the temperature dependence of the critical thickness of the Stranski–Krastanov transition, which has been the subject of constant scientific disputes until now.
Investigating the thermal transport in gold decorated graphene by opto-thermal Raman technique
Authors: M K Ranjuna , Balakrishnan Jayakumar 
Published: December 2021

Abstract
We report a systematic study on the thermal transport properties of gold nanoparticles (Au NPs) decorated single-layer graphene on a SiO2/Si substrate by the opto-thermal Raman technique. Our results, with moderate Au NPs coverage (<10%), demonstrate an enhancement in the thermal conductivity of graphene by ∼55% from its pristine value and a decrement in the interface conductance by a factor of 1.5. A detailed analysis of our results shows the importance of the photo-thermal conversion efficiency of Au NPs, plasmon–phonon coupling and lattice modifications in the graphene developed after gold nanoparticles deposition in enhancing the thermal conductivity and reducing the interface thermal conductance of the system. Our study paves way for a better understanding of the thermal management in such hybrid systems, which are envisioned as excellent candidates for optoelectronics and photonics applications.
In-plane InGaAs/Ga(As)Sb nanowire based tunnel junctions grown by selective area molecular beam epitaxy
Authors: Bucamp A , Coinon C , Lepilliet S , Troadec D , Patriarche G , Diallo M H , Avramovic V , Haddadi K , Wallart X , Desplanque L 
Published: December 2021

Abstract
In-plane InGaAs/Ga(As)Sb heterojunction tunnel diodes are fabricated by selective area molecular beam epitaxy with two different architectures: either radial InGaAs core/Ga(As)Sb shell nanowires or axial InGaAs/GaSb heterojunctions. In the former case, we unveil the impact of strain relaxation and alloy composition fluctuations at the nanoscale on the tunneling properties of the diodes, whereas in the latter case we demonstrate that template assisted molecular beam epitaxy can be used to achieve a very precise control of tunnel diodes dimensions at the nanoscale with a scalable process. In both cases, negative differential resistances with large peak current densities are achieved.
Automatic detection of respiratory events during sleep from Polysomnography data using Layered Hidden Markov Model
Authors: Sadoughi Azadeh , Shamsollahi Mohammad Bagher , Fatemizadeh Emad 
Published: December 2021

Abstract

Objective. Sleep apnea is a serious respiratory disorder, which is associated with increased risk factors for cardiovascular disease. Many studies in recent years have been focused on automatic detection of sleep apnea from polysomnography (PSG) recordings, however, detection of subtle respiratory events named Respiratory Event Related Arousals (RERAs) that do not meet the criteria for apnea or hypopnea is still challenging. The objective of this study was to develop automatic detection of sleep apnea based on Hidden Markov Models (HMMs) which are probabilistic models with the ability to learn different dynamics of the real time-series such as clinical recordings. Approach. In this study, a hierarchy of HMMs named Layered HMM was presented to detect respiratory events from PSG recordings. The recordings of 210 PSGs from Massachusetts General Hospital’s database were used for this study. To develop detection algorithms, extracted feature signals from airflow, movements over the chest and abdomen, and oxygen saturation in blood (SaO2) were chosen as observations. The respiratory disturbance index (RDI) was estimated as the number of apneas, hypopneas, and RERAs per hour of sleep. Main results. The best F1 score of the event by event detection algorithm was between 0.22 ± 0.16 and 0.70 ± 0.08 for different groups of sleep apnea severity. There was a strong correlation between the estimated and the PSG-derived RDI (R
2 = 0.91, p < 0.0001). The best recall of RERA detection was achieved 0.45 ± 0.27. Significance. The results showed that the layered structure can improve the performance of the detection of respiratory events during sleep.
A mechanical true random number generator
Authors: Akashi Nozomi , Nakajima Kohei , Shibayama Mitsuru , Kuniyoshi Yasuo 
Published: December 2021

Abstract
Random number generation has become an indispensable part of information processing: it is essential for many numerical algorithms, security applications, and in securing fairness in everyday life. Random number generators (RNGs) find application in many devices, ranging from dice and roulette wheels, via computer algorithms, lasers to quantum systems, which inevitably capitalize on their physical dynamics at respective spatio-temporal scales. Herein, to the best of our knowledge, we propose the first mathematically proven true RNG (TRNG) based on a mechanical system, particularly the triple linkage of Thurston and Weeks. By using certain parameters, its free motion has been proven to be an Anosov flow, from which we can show that it has an exponential mixing property and structural stability. We contend that this mechanical Anosov flow can be used as a TRNG, which requires that the random number should be unpredictable, irreproducible, robust against the inevitable noise seen in physical implementations, and the resulting distribution’s controllability (an important consideration in practice). We investigate the proposed system’s properties both theoretically and numerically based on the above four perspectives. Further, we confirm that the random bits numerically generated pass the standard statistical tests for random bits.
Pressure-driven wrinkling of soft inner-lined tubes
Authors: Foster Benjamin , Verschueren Nicolás , Knobloch Edgar , Gordillo Leonardo 
Published: December 2021

Abstract
A simple equation modelling an inextensible elastic lining of an inner-lined tube subject to an imposed pressure difference is derived from a consideration of the idealised elastic properties of the lining and the pressure and soft-substrate forces. Two cases are considered in detail, one with prominent wrinkling and a second one in which wrinkling is absent and only buckling remains. Bifurcation diagrams are computed via numerical continuation for both cases. Wrinkling, buckling, folding, and mixed-mode solutions are found and organised according to system-response measures including tension, in-plane compression, maximum curvature and energy. Approximate wrinkle solutions are constructed using weakly nonlinear theory, in excellent agreement with numerics. Our approach explains how the wavelength of the wrinkles is selected as a function of the parameters in compressed wrinkling systems and shows how localised folds and mixed-mode states form in secondary bifurcations from wrinkled states. Our model aims to capture the wrinkling response of arterial endothelium to blood pressure changes but applies much more broadly.
Thermodynamic optimization of nanofluid flow over a non-isothermal wedge with nonlinear radiation and activation energy
Authors: Acharya M R , Mishra P , Panda S 
Published: December 2021

Abstract
This paper analyses the augmentation entropy generation number for a viscous nanofluid flow over a non-isothermal wedge including the effects of non-linear radiation and activation energy. We discuss the influence of thermodynamically important parameters during the study, namely, the Bejan number, entropy generation number, and the augmentation entropy generation number. The mathematical formulation for thermal conductivity and viscosity of nanofluid for Al
2
O
3 − EG mixture has been considered. The results were numerically computed using implicit Keller-Box method and depicted graphically. The important result is the change in augmentation entropy generation number with Reynolds number. We observed that adding nanoparticles (volume fraction) tend to enhance augmentation entropy generation number for Al
2
O
3 − EG nanofluid. Further, the investigation on the thermodynamic performance of non-isothermal nanofluid flow over a wedge reveals that adding nanoparticles to the base fluid is effective only when the contribution of heat transfer irreversibility is more than fluid friction irreversibility. This work also discusses the physical interpretation of heat transfer irreversibility and pressure drop irreversibility. This dependency includes Reynolds number and volume fraction parameter. Other than these, the research looked at a variety of physical characteristics associated with the flow of fluid, heat and mass transfer.
Evaporating primordial black holes in gamma ray and neutrino telescopes
Authors: Capanema Antonio , Esmaeili AmirFarzan , Esmaili Arman 
Published: December 2021

Abstract
A primordial black hole in the last stages of evaporation and located in the local neighborhood can produce a detectable signal in gamma ray and neutrino telescopes. We re-evaluate the expected gamma ray and neutrino fluxes from these transient point events and discuss the consequences for existing constraints. For gamma rays we improve the current bounds by a factor of few, while for neutrinos we obtain significantly different results than the existing literature. The capability and advantages of neutrino telescopes in the search for primordial black holes is discussed thoroughly. The correlations of gamma ray and neutrino energy and time profiles will be promoted as a powerful tool in identifying the primordial black holes, in case of detection.
Alfvén cascade eigenmodes above the TAE-frequency and localization of Alfvén modes in D–3He plasmas on JET
Authors: Dreval M. , Sharapov S.E. , Kazakov Ye.O. , Ongena J. , Nocente M. , Calado R. , Coelho R. , Ferreira J. , Figueiredo A. , Fitzgerald M. , Garcia J. , Giroud C. , Hawkes N.C. , Kiptily V.G. , Nabais F. , Nave M.F.F. , Weisen H. , Craciunescu T. , Salewski M. , Štancar Ž. , JET Contributors  
Published: December 2021

Abstract
Various types of Alfvén eigenmodes (AEs) have been destabilized by fast ions over a broad frequency range from ∼80 kHz to ∼700 kHz in a series of JET experiments in mixed D–3He plasmas heated with the three-ion ICRF scenario (2020 Nocente et al Nucl. Fusion
60 124006). In this paper, we identify the radial localization of AEs using an X-mode reflectometer, a multiline interferometer and soft x-ray diagnostics. The analysis is focused on the most representative example of these measurements in JET pulse #95691, where two different types of Alfvén cascade (AC) eigenmodes were observed. These modes originate from the presence of a local minimum of the safety factor q
min. In addition to ACs with frequencies below the frequency of toroidal Alfvén eigenmodes (TAEs), ACs with frequencies above the TAE frequency were destabilized by energetic ions. Both low- (f ≈ 80–180 kHz) and high-frequency (f ≈ 330–450 kHz) ACs were localized in the central regions of the plasma. The characteristics of the high-frequency ACs are investigated in detail numerically using HELENA, CSCAS and MISHKA codes. The resonant conditions for the mode excitation are found to be determined by passing ions of rather high energy of several hundred keV and similar to those established in JT-60U with negative-ion-based NBI (2005 Takechi et al Phys. Plasmas
12 082509). The computed radial mode structure is found to be consistent with the experimental measurements. In contrast to low-frequency ACs observed most often, the frequency of the high-frequency ACs decreases with time as the value of q
min decreases. This feature is in a qualitative agreement with the analytical model of the high-frequency ACs in Breizman et al (2003 Phys. Plasmas
10 3649). The high-frequency AC could be highly relevant for future ITER and fusion reactor plasmas dominated by ∼MeV energetic ions, including a significant population of passing fast ions.
Pixel chamber: a solid-state active-target for 3D imaging of charm and beauty
Authors: Mulliri A. , Arba M. , Bhattacharya P. , Casula E. , Cicalò C. , De Falco A. , Mager M. , Marras D. , Masoni A. , Musa L. , Siddhanta S. , Tuveri M. , Usai G. 
Published: December 2021

Abstract
The aim of the pixel chamber project is to develop the first “solid-state bubble chamber” for high precision measurement of charm and beauty. In this paper we will describe the idea for the first silicon active target conceived as an ultra-high granular stack of hundreds of very thin monolithic active pixel sensors (MAPS), which provides continuous, high-resolution 3D tracking of all of the particles produced in proton-silicon interactions occurring inside the detector volume, including open charm and beauty. We will also discuss the high-precision tracking and vertexing performances, showing that the vertex resolution can be up to one order of magnitude better than state-of-the-art detectors like the LHCb one.
Segmentation of EM showers for neutrino experiments with deep graph neural networks
Authors: Belavin V. , Trofimova E. , Ustyuzhanin A. 
Published: December 2021

Abstract
We introduce a first-ever algorithm for the reconstruction
of multiple showers from the data collected with electromagnetic
(EM) sampling calorimeters. Such detectors are widely used in High
Energy Physics to measure the energy and kinematics of in-going
particles. In this work, we consider the case when many electrons
pass through an Emulsion Cloud Chamber (ECC) brick, initiating
electron-induced electromagnetic showers, which can be the case with
long exposure times or large input particle flux. For example, SHiP
experiment is planning to use emulsion detectors for dark matter
search and neutrino physics investigation. The expected full flux of
SHiP experiment is about 1020 particles over five years. To
reduce the cost of the experiment associated with the replacement of
the ECC brick and off-line data taking (emulsion scanning), it is
decided to increase exposure time. Thus, we expect to observe a lot
of overlapping showers, which turn EM showers reconstruction into a
challenging point cloud segmentation problem. Our reconstruction
pipeline consists of a Graph Neural Network that predicts an
adjacency matrix and a clustering algorithm. We propose a new layer
type (EmulsionConv) that takes into account geometrical properties
of shower development in ECC brick. For the clustering of
overlapping showers, we use a modified hierarchical density-based
clustering algorithm. Our method does not use any prior information
about the incoming particles and identifies up to 87% of
electromagnetic showers in emulsion detectors. The achieved energy
resolution over 16,577 showers is
σE/E = (0.095 ± 0.005) + (0.134 ±
0.011)/√(E). The main test bench for the algorithm for
reconstructing electromagnetic showers is going to be SND@LHC.
The stress measurement system for the JUNO Central Detector acrylic panels
Authors: Yang X. , Heng Y. , Li Z. , Ma X. , Qian X. , Huang K. , Wu Z. , Xu M. , He W. , Pei Y. , Wang Y. 
Published: December 2021

Abstract
The Jiangmen Underground Neutrino Observatory (JUNO) Central
Detector (CD) is a huge acrylic spherical vessel containing 20,000
tons of liquid scintillator; the sphere is composed of 263 pieces of
acrylic spherical panels bonded by the mass polymerization. The
operation life time of the JUNO CD is 20 years. To ensure the
structural safety during the JUNO CD life time, the acrylic stress
of CD is required not to be greater than 3.5 MPa. The stresses of
acrylic spherical panels are required to be measured during the
installation on-site; unfortunately there is no suitable commercial
measurement equipment that can meet JUNO's requirements. Therefore,
a measurement setup based on photo-elastic principle and
spectrometric methods was designed, developed and tested for on-site
measurements. The measurement system performs accurate calibration
of stress-optical coefficient of acrylic in JUNO, and gives reliable
results of acrylic stresses. The measurement system has been tested
in the Taixing Donchamp Acrylic Ltd mechanical workshop, and the
achieved results meet the JUNO's requirements. The measurement
principle, the system components, and the tooling design are
introduced in the paper. Moreover, the calibration of stress-optical
coefficient of the acrylic and measurements results on JUNO acrylic
spherical panels are discussed in the following.
Frequency-tunable wide-angle polarization selection with a graphene-based anisotropic epsilon-near-zero metamaterial
Authors: Wu Feng , Liu Dejun , Wu Xiaohu , Li Hongju , Xiao Shuyuan 
Published: December 2021

Abstract
In this paper, we achieve frequency-tunable wide-angle polarization selection based on an anisotropic epsilon-near-zero (AENZ) metamaterial mimicked by a subwavelength graphene/SiO2 multilayer. The physical mechanism of wide-angle polarization selection can be explained by the analysis of the iso-frequency curve (IFC). Under transverse electric polarization, only the incident lights which are close to normal incidence can transmit through the designed multilayer since the IFC of the AENZ metamaterial is an extremely small circle. However, under transverse magnetic polarization, all the incident lights can transmit through the designed multilayer since the IFC of the AENZ metamaterial is a flat ellipse. Therefore, polarization selection can work in a broad angular width. By changing the gate voltage applying to the graphene, the operating frequency of polarization selection can be flexibly tuned. The optimal operating angular width of high-performance polarization selection where the polarization selection ratio is larger than 102 reaches 54.9°. This frequency-tunable wide-angle polarization selector would possess potential applications in liquid crystal display, read-write magneto-optical data storage, Q-switched lasing, and chiral molecule detection.
High tunability and sensitivity of 1D topological photonic crystal heterostructure
Authors: Elshahat Sayed , Mohamed Zain Elabdeen A , Almokhtar Mohamed , Lu Cuicui 
Published: December 2021

Abstract
A modality to high tunability and sensing performance of a one-dimensional (1D) topological photonic crystal (PC) heterostructure is realized, based on a new mechanism through a 1D topological PC. By inserting an aqueous defect layer as a sandwich between two 1D PCs, transmittance gradually decreases with the increasing thickness of the defect layer. However, when the two layers of the topological heterostructure interface are replaced by the defect layer, the tunability and all sensing capabilities are improved, and the principle of topology is preserved. A topologically protected edge state is formed at the heterostructure interface with a highly localized electric field. For glucose sensing, high sensitivity S = 603.753 nm RIU−1 is obtained at the low detection limit of about DL = 1.22 ×

10

−
4

RIU with high-quality factor Q =

2.33
×

10
4

and a high figure of merit FOM =

8147.814

RI

U

−
1

. Besides, the transmittance can be maintained at over 99% at low and/or high glucose concentrations, due to the coupling topological edge mode between defect mode and topological edge state. An excellent platform is examined to design a topological photonic sensor. This flexible platform can be used for any type of sensor solely by replacing the interface layers with different sensor materials. Thus, our results will promote the development of 1D topological photonic devices.