bluuebunny/crossref_metadata_2025 huggingface dataset:
THz microscope for three-dimensional imaging with superconducting Josephson junctions
Authors: Tollkühn M. , Ritter P. J. , Schilling M. , Hampel B.
Published: April 2022

Superconducting Josephson junctions have a wide range of applications ranging from quantum computing to voltage standards, and they may also be employed as versatile sensors for high-frequency radiation and magnetic fields. In this work, we present a unique measurement setup utilizing a single Josephson junction on a cantilever for high-resolution spatial measurements of spectroscopically resolved THz and microwave field distributions. This THz microscope can be utilized to measure power and frequency of electromagnetic radiation from ∼1 GHz to 5 THz. It may also be used to measure static magnetic fields and provide topological scans of samples. The samples can be both actively radiating or passively irradiated at either room temperature or cryogenic temperatures. We review the measurement setup of the THz microscope and describe the evaluation of its measurement data to achieve three-dimensional visualizations of the field distributions. The diverse capabilities of this unique tool are demonstrated by its different measurement modes with measurements of field distributions at 20 GHz and 1.4 THz, spectroscopically resolved THz measurements, and magnetic field measurements.
Objective evaluation of wearable thermoelectric generator: From platform building to performance verification
Authors: Xu Zhuoming , Yang Dongwang , Yuan Xiong , Hua Siheng , You Han , Xing Yubing , Hu Kai , Wang Jiang , Xiao Yani , Yan Yonggao , Tang Xinfeng
Published: April 2022

Wearable thermoelectric generators can harvest heat from the human body to power an intelligent electronic device, which plays an important role in wearable electronics. However, due to the complexity of human skin, there is still no unified standard for performance testing of wearable thermoelectric generators under wearable conditions. Herein, a test platform suitable for a wearable thermoelectric generator was designed and built by simulating the structure of the arm. Based on the biological body temperature regulation function, water flow and water temperature substitute blood flow and blood temperature, the silicone gel with some thickness simulates the skin layer of the human arm, thus achieving the goal of adjusting the thermal resistance of human skin. Meanwhile, the weight is used as the contact pressure to further ensure the reliability and accuracy of the test data. In addition, the environment regulatory system is set up to simulate the outdoor day. Actually, the maximum deviation of the performance of the thermoelectric generator worn on the test platform and human arm is ∼5.2%, indicating the accuracy of objective evaluation.
The effects of nose bluntness on broadband disturbance receptivity in hypersonic flow
Authors: He Simon , Zhong Xiaolin
Published: April 2022

While nose bluntness is known to have a large impact on the stability of hypersonic vehicles, its influence on the freestream receptivity process has not been fully characterized for a wide range of conditions. This paper investigates the effects of nose bluntness on the second mode receptivity coefficients and the development of boundary layer disturbances over two 7° half-angle circular blunt cones at Mach 10 after perturbation with broadband freestream pulses of different types. The cones have nose radii of 9.525 mm (case B) and 5.08 mm (case I). Unsteady direct numerical simulation (DNS) and linear stability theory (LST) results compare well and predict stronger second mode growth for case I in all pulse cases. Unsteady DNS also shows variations in extramodal excitation between the cones depending on freestream disturbance type. Spectral receptivity coefficients are generated by decomposing the unsteady DNS data into discrete frequency Fourier modes, which are then corrected with LST N-factors. Fast acoustic disturbances demonstrate minimal variation in receptivity coefficients, while temperature and vorticity disturbances have much higher coefficients in case I. Planar slow acoustic pulses induce stronger disturbances outside of the second mode in case I, resulting in higher peak receptivity coefficients. Results show significant variation in receptivity response based on nose bluntness, pulse geometry, and the type of incident perturbation.
Changes in mononuclear immune cells during bovine pregnancy
Authors: Rutigliano Heloisa M. , Leppo Kelsy A. , Morgado Kira P.
Published: April 2022

This study aimed to determine the differences in gene expression between mononuclear cells derived from peripheral blood and endometrium during pregnancy in cattle and to determine the proportion of mononuclear cells in the endometrium of pregnant and diestrous cows. Endometrial tissue and peripheral blood were collected from Day 34 ± 2 pregnant cows, and mononuclear cell populations were quantified and sorted (n = 5). The relative mRNA levels of inflammatory mediators was assessed by quantitative real time polymerase chain reaction. During pregnancy, the proportion of CD8+, CD4+, CD4+CD25− and CD4+CD25dim cells among mononuclear cells was greater in blood than endometrium, and cells positive for CD14 and CD68 expressed greater mRNA amounts of interleukin (IL) 6, CXCL8 and IL10 in endometrium compared with blood. Cells positive for γ/δ-T cell receptor expressed greater amounts of IL1A transcript in the endometrium than in blood of diestrous cows, CD4+CD25bright cells expressed more CTLA4 mRNA in the endometrium compared with blood of diestrous cows, and endometrial natural killer cells expressed greater CXCL8 mRNA compared with blood of pregnant and diestrous cows. The percentages of CD21+, NCR1+, CD8+, FoxP3+, CD3+ and CD68+ cells were greater in the endometrium of Day 35 pregnant cows compared with diestrous cows.
New high-yielding, stress-resilient, and nutritious crop varieties.
Authors: Okori Patrick , Chirwa Rowland , Chisale Virginia , Jumbo MacDonald Bright , Makumba Wilkson , Makumbi Dan , Matumba Annie , Mosha Inviolate , Munthali Wills , Nadigatla Gangarao , Ngowi Peter , Njeru James , Ochieng Justus , Setimela Peter , Swai Elirehema , Tarekegne Amsal
Published: April 2022

This chapter describes the performance of new cereal and legume crop varieties introduced by Africa RISING into agroecosystems in which they had not been tested before. The introduced varieties are characterized by their resilience to drought and/or their improved nutritional content.
Improved feeding for dairy cattle and poultry in smallholder crop-livestock systems.
Authors: Mpairwe Denis , Mutetikka David
Published: April 2022

This chapter describes how cropping systems can be used to supplement feeds to increase dairy and poultry yields. It completes the concept of on-farm integration of crop, livestock and natural resources technologies necessary for sustainable intensification on smallholder farms. The different processes that utilize different feed sources to produce better-quality feed rations for dairy cows and poultry are also discussed.
Combining multiple technologies: integrated soil fertility management.
Authors: Bekunda Mateete , Chikowo Regis , Claessens Lieven , Hoeschle-Zeledon Irmgard , Kihara Job , Kizito Fred , Okori Patrick , Sognigbé N'Danikou , Thierfelder Christian
Published: April 2022

This chapter shows how Integrated Soil Fertility Management (ISFM) can be combined and integrated further at farm and landscape levels to improve farming system performance. ISFM is an example of a system-wide technology. It is a set of soil fertility management practices, including use of industrial fertilizer, organic inputs, and improved crop varieties, combined with knowledge on how to adapt the practices to local conditions. Its benefits include agronomic efficiency, enhanced productivity, reduced risk, reduced need for industrial fertilizers, and reduction in post-harvest losses. The farmers' responses and opportunities for adoption are also discussed.
Trends in Buprenorphine-Waivered Providers in Medicaid Expansion and Non-Expansion States by Their Public Listing Status
Authors: Sanmartin Maria X. , Ali Mir M. , Dwyer Debra S.
Published: April 2022

Background: The federal government has made several efforts to increase access to buprenorphine for the treatment of opioid use disorder (OUD). However, patients continue to face challenges in access to treatment for OUD. Objectives: This study seeks to examine the trends in the prevalence of buprenorphine-waivered practitioners who opt to be publicly listed on the Buprenorphine Treatment Practitioner Locator tool maintained by the Substance Abuse and Mental Health Services Administration (SAMHSA) and how this varies between Medicaid expansion and non-expansion states. Methods: Administrative records of all the DATA-waivered providers collected by SAMHSA were utilized to identify the trends in the number of waivered practitioners by their public listing status from 2002–2017. We further examine how that trend varied between Medicaid expansion and non-expansion states. Results: The total number of waivered providers increased steadily from 300 in 2002 to 41,960 in 2017. In 2015, the number of waivered providers began to increase rapidly, with the number in Medicaid expansion states increasing faster than in non-expansion states from 2014–2017 (136% vs. 59%). Even though a greater proportion of waivered providers listed their names publicly in non-expansion states than in expansion states from 2014–2017, the rate of public listing of names increased more rapidly in Medicaid expansion states than in non-expansion states (170% vs. 85%) during the same period. Conclusions: This finding suggests that even though there has been an increase in waivered providers to prescribe buprenorphine in Medicaid expansion and non-expansion states, barriers to access treatment still persist. Policy initiatives that seek to expand access to substance-use treatment are warranted.
A multiple scattering theoretical approach to time delay in high energy core-level photoemission of heteronuclear diatomic molecules
Authors: Tamura Y , Yamazaki K , Ueda K , Hatada K
Published: April 2022

We present analytical expressions of momentum-resolved core-level photoemission time delay in a molecular frame of a heteronuclear diatomic molecule upon photoionization by a linearly polarized soft x-ray attosecond pulse. For this purpose, we start to derive a general expression of photoemission time delay based on the first order time dependent perturbation theory within the one electron and single channel model in the fixed-in-space system (atoms, molecules and crystals) and apply it to the core-level photoemission within the electric dipole approximation. By using multiple scattering theory and applying series expansion, plane wave and muffin-tin approximations, the core-level photoemission time delay

t

is divided into three components,

t
abs

,

t
path

and

t
sc

, which are atomic photoemission time delay, delays caused by the propagation of photoelectron among the surrounding atoms and the scattering of photoelectron by them, respectively. We applied a single scattering approximation to

t
path

and obtained

t

path

(

1

)

(

k
,
θ

)

for a linearly polarized soft x-ray field with polarization vector parallel to the molecular axis for a heteronuclear diatomic molecule, where

θ

is the angle of measured photoelectron from the molecular axis. The core-level photoemission time delay

t

is approximated well with this simplified expression

t

path

(

1

)

(

k
,
θ

)

in the high energy regime (

k

≳

3
.
5

 a.u.−1, where

k

is the amplitude of photoelectron momentum

k

), and the validity of this estimated result is confirmed by comparing it with multiple scattering calculations for C 1s core-level photoemission time delay of CO molecules.

t

path

(

1

)

(

k
,
θ

)

shows a characteristic dependence on θ, it becomes zero at θ = 0°, exhibits extended x-ray absorption fine structure type oscillation with period

2
k
R

at θ = 180°, where R is the bondlength, and gives just the travelling time of photoelectron from the absorbing atom to the neighbouring atom at θ = 90°. We confirmed these features also in the numerical results performed by multiple scattering calculations.
Experimental study of the evolution of H

α

line profile in a pulse hydrogen discharge
Authors: Bozhinova I , Pashov A , Iordanova S
Published: April 2022

This study reports on experimental technique for investigation of the dynamics of neutrals in direct current hydrogen discharges at low pressures. It is based on analysis of anomalous broadening of the H

α

emission line profile in a pulsed regime of operation of the source. The application of the technique is relatively simple and it is illustrated in a coaxial discharge tube, but can be readily extended to various discharge sources. The emission line is analyzed by a Fabry-Pérot interferometer and therefore high spectral resolution and fast temporal response can be combined. By observing the evolution of the profile with the pulse duration the experimental technique, extended with numerical modelling, gives opportunity for obtaining useful information about the temporal dependence of the processes responsible for formation of the components of the profile.
Acoustic-based method for identifying surface damage to wind turbine blades by using a convolutional neural network
Authors: Tsai Tung-Chen , Wang Chao-Nan
Published: April 2022

Damage to the surface of the blades of a large wind turbine may lead to catastrophic blade failure. Although numerous methods have been proposed for detecting surface damage to wind turbine blades, many of them involve laboratory tests because of the difficulty in acquiring data from a commercial wind farm. This lack of data variety is an obstacle to the development of machine learning approaches for identifying the aforementioned damage. Therefore, we developed a damage detection method for wind turbine blade surfaces that is based on the physical correlation between surface conditions and acoustic signals of operating wind turbines under realistic environmental conditions. In the preprocessing stage of the aforementioned method, the short-time Fourier transform and smoothing techniques are used to analyze real-time spectrograms and the rotor speed. The derived spectrogram and rotor speed are then input into a convolutional neural network (CNN) to classify the wind turbine blade surfaces into two classes: turbines with at least one or no damaged blade. The CNN proposed in this paper is a hybrid network containing a masking module and residual classifier. The masking module suppresses redundant information in the spectrogram, and the residual classifier quantifies the difference between the masked spectrogram and a standard spectrogram. The proposed CNN can be easily trained on a small dataset with a few trainable parameters by using the physical characteristics in the residual classifier. The proposed damage detection method was evaluated using the operational noise of commercial wind turbines; according to the results, this method outperformed approaches proposed in previous studies and exhibited an accuracy of 97.11%.
Influence of twist pitch on hysteretic losses and transport J

c
in overpressure processed high J

c
Bi-2212 round wires
Authors: Oz Y , Davis D , Jiang J , Hellstrom E E , Larbalestier D C
Published: April 2022

Bi-2212 is the only high field, high-temperature superconductor (HTS) available in the macroscopically isotropic, multifilament high J

c
round wire (RW) form capable of generating high uniformity fields with minimum-screening current errors. However, the heat treatment that enables impressively high J

c
(4.2 K, 30 T) values that can attain ∼5000 A mm−2 also produces significant filament bonding (bridging). Filament bridging appears to significantly enhance hysteretic losses of the filaments themselves by coupling neighboring, nominally independent filaments, enabling shielding currents to flow across multiple filaments as though they were one filament of much larger diameter. Wire twisting can be employed to reduce filament-to-filament eddy current coupling losses due to induced currents flowing across the matrix, but twisting is less effective in reducing increased losses from bridging. Here, we compare the twist-pitch dependence of the losses of overpressure processed (OP) high J

c
Bi-2212 RWs with partially bridged filaments to those found in OP Bi-2212 RWs with discrete, not-bridged filaments. We show that filament sub-bundles in standard, partially-bridged wires that have some superconducting connections between filaments can exhibit significant coupling (much larger effective filament diameter), but twisting still reduces their hysteretic losses to values close to or below the ITER Nb3Sn wire loss specification, even though Bi-2212 wires have significantly larger J

c
values. Although it has been reported that twisting can reduce wire J

c
by damaging filaments, we found no reduction in transport J

c
, even for nominal twist pitches of 12 mm in 0.8 mm diameter wires. Evaluation of more-recent, higher J

c
Engi-Mat powder wires showed that their reduced filament bridging and improved longitudinal connectivity significantly improved transport J

c
and reduced the J

c
normalized losses, signaling that J

c
can be further improved without commensurate increase in losses. This important result strengthens the argument for production of high field, low loss HTS magnets made with Bi-2212 RWs.
Waveform of free, hinged and clamped axonemes isolated from C. reinhardtii: influence of calcium
Authors: Gholami A , Ahmad R , Bae A J , Pumir A , Bodenschatz E
Published: April 2022

The beating of cilia and flagella is essential to perform many important biological functions, including generating fluid flows on the cell surface or propulsion of micro-organisms. In this work, we analyze the motion of isolated and demembranated flagella from green algae Chlamydomonas reinhardtii, which act as ATP-driven micro-swimmers. The beating flagella of Chlamydomonas exhibit an asymmetric waveform that is known to involve the superposition of a static component, corresponding to a fixed, intrinsic curvature, and a dynamic wave component traveling from base-to-tip at the fundamental beat frequency, plus higher harmonics. Here, we analyse free, hinged and clamped axonemes using principal component analysis. The axonemal motion is described with a high degree of accuracy, taking into account only the first four dominant eigenmodes. Our analysis suggests that the wave motion can be alternatively described with Fourier modes, with a wavelength λ, larger than the length of the filament L (λ/L ≈ 1.3). Within this representation, we demonstrate that the main base-to-tip traveling wave component coexists with standing waves. Finally, we report the effect of calcium on the constituting wave components and find that the static mode is the most sensitive component to the calcium ion concentration.
Dynamic response of the half-space subjected to a moving point load and thermal stress
Authors: Zhou Xiang , Shui Guoshuang , Su Xiao-Xing
Published: April 2022

Dynamic transient response of the half-space subjected to a moving point load and thermal stress is investigated analytically in this study. By employing the Helmholtz decomposition and introducing a moving coordinate system, the corresponding modified partial differential equations of motion for the transient waves in the half-space are firstly obtained. With one-side and two-side Laplace transformation over the new time and space variables, the second-order partial differential equations of motion in the modified system are then simplified as the ordinary differential equations, whose solutions are thereafter obtained when the boundary condition is satisfied. To get the dynamic response in time domain, the analytical solutions in Laplace domain are inverted using the Cagniard-de Hoop method. Some examples are evaluated and discussed in details for the purpose of examining the effect of the moving load and thermal stress on the transient response of the half-space.
Gravitational shine of dark domain walls
Authors: Babichev E. , Gorbunov D. , Ramazanov S. , Vikman A.
Published: April 2022

Cosmic domain walls are harmless, provided that their tension decreases with expansion of the Universe. This setup can be realized, if the scale of spontaneous symmetry breaking is induced dynamically through the interaction with hot primordial plasma. In that case, the domain wall tension can attain large values in the early Universe without any conflict with observations. Owing to the large initial tension, these topological defects may serve as a powerful source of gravitational waves. We make a preliminary estimate of the gravitational wave spectrum and argue that it is distinct from the spectrum produced by other sources, in particular by domain walls of a constant tension. The resulting gravitational wave signal is in the range accessible by Einstein Telescope, DECIGO, TianQin, LISA, IPTA, or SKA, if the field constituting the domain walls is very feebly coupled with hot primordial plasma and has tiny self-interactions. In particular, one can consider this field for the role of Dark Matter. We discuss various Dark Matter production mechanisms and properties of the emitted gravitational waves associated with them. We find that the conventional freeze-out and freeze-in mechanisms lead to large and perhaps unobservable frequency of gravitational waves. However, the Dark Matter production is also possible at the second order phase transition leading to the domain wall formation or at the inverse phase transition, when the domain walls get dissolved eventually. In both cases, there is essentially no lower bound on the frequency of emitted gravitational waves.
Polarization angle requirements for CMB B-mode experiments. Application to the LiteBIRD satellite
Authors: Vielva P. , Martínez-González E. , Casas F.J. , Matsumura T. , Henrot-Versillé S. , Komatsu E. , Aumont J. , Aurlien R. , Baccigalupi C. , Banday A.J. , Barreiro R.B. , Bartolo N. , Calabrese E. , Cheung K. , Columbro F. , Coppolecchia A. , de Bernardis P. , de Haan T. , de la Hoz E. , De Petris M. , Della Torre S. , Diego-Palazuelos P. , Eriksen H.K. , Errard J. , Finelli F. , Franceschet C. , Fuskeland U. , Galloway M. , Ganga K. , Gervasi M. , Génova-Santos R.T. , Ghigna T. , Gjerløw E. , Gruppuso A. , Hazumi M. , Herranz D. , Hivon E. , Kohri K. , Lamagna L. , Leloup C. , Macias-Perez J. , Masi S. , Matsuda F.T. , Morgante G. , Nakano R. , Nati F. , Natoli P. , Nerval S. , Odagiri K. , Oguri S. , Pagano L. , Paiella A. , Paoletti D. , Piacentini F. , Polenta G. , Puglisi G. , Remazeilles M. , Ritacco A. , Rubino-Martin J.A. , Scott D. , Sekimoto Y. , Shiraishi M. , Signorelli G. , Takakura H. , Tartari A. , Thompson K.L. , Tristram M. , Vacher L. , Vittorio N. , Wehus I.K. , Zannoni M.
Published: April 2022

A methodology to provide the polarization angle requirements for different sets of detectors, at a given frequency of a CMB polarization experiment, is presented. The uncertainties in the polarization angle of each detector set are related to a given bias on the tensor-to-scalar ratio r parameter. The approach is grounded in using a linear combination of the detector sets to obtain the CMB polarization signal. In addition, assuming that the uncertainties on the polarization angle are in the small angle limit (lower than a few degrees), it is possible to derive analytic expressions to establish the requirements. The methodology also accounts for possible correlations among detectors, that may originate from the optics, wafers, etc. The approach is applied to the LiteBIRD space mission. We show that, for the most restrictive case (i.e., full correlation of the polarization angle systematics among detector sets), the requirements on the polarization angle uncertainties are of around 1 arcmin at the most sensitive frequency bands (i.e., ≈ 150 GHz) and of few tens of arcmin at the lowest (i.e., ≈ 40 GHz) and highest (i.e., ≈ 400 GHz) observational bands. Conversely, for the least restrictive case (i.e., no correlation of the polarization angle systematics among detector sets), the requirements are ≈ 5 times
less restrictive than for the previous scenario. At the global and the telescope levels, polarization angle knowledge of a few arcmins is sufficient for correlated global systematic errors and can be relaxed by a factor of two for fully uncorrelated errors in detector polarization angle. The reported uncertainty levels are needed in order to have the bias on r due to systematics below the limit established by the LiteBIRD collaboration.
Generation of unconventional burst-pulse bundle in ytterbium-doped double-clad fiber laser based on self-mode-locked and double passively Q-switched technologies
Authors: Zhou Cheng
Published: April 2022

We experimentally demonstrate the unconventional burst-pulse bundle generation in a linear-cavity ytterbium-doped double-clad fiber laser based on self-mode-locked and double passively-Q-switched technologies. When the pump power is 4421.0 mW, we obtained the burst pulse bundle with proportional pulse qualities. The full width at half maximum (FWHM) of the burst pulse is 2.2 μs, the time interval between the adjacent burst pulse is 2.4 μs and the energy of a single burst pulse is 0.62 μJ. In addition, the maximum burst-pulse energy is 0.85 μJ at the pump power of 4574.0 mW, the minimum FWHM and time interval are 1.7 and 1.4 μs at the pump power of 5387.0 mW. The formation mechanism of the unconventional burst pulse bundle is also discussed in detail.
Laser ablation of Fe2B target enriched in 10B content for boron neutron capture therapy
Authors: Aiyyzhy Kuder O , Barmina Ekaterina V , Zavestovskaya Irina N , Kasatova Anna I , Petrunya Dmitry S , Uvarov Oleg V , Saraykin Vladimir V , Zhilnikova Margarita I , Voronov Valery V , Shafeev Georgy A , Taskaev Sergey Yu , Zelepukin Ivan V , Deyev Sergey M
Published: April 2022

The technique of laser ablation in liquids is applied to produce Boron-containing nanoparticles from ablation of a Fe2B bulk target enriched in 10B isotope. Laser ablation of the target in liquid isopropanol results in partial disproportionation to free Fe and Boron while nanoparticles of Fe2B are also presented. The nanoparticles are magnetic and can be collected using a permanent magnet. The average size of nanoparticles is about 15 nm. The content of 10B in the generated nanoparticles amounts to 76.9%. The nanoparticles are biocompatible and can be used in boron neutron capture therapy.
Relativistic elastic scattering of an electron by a muon in the field of a circularly polarized electromagnetic wave
Authors: Mekaoui Y , Jakha M , Mouslih S , Manaut B , Benbrik R , Taj S
Published: April 2022

Within the framework of quantum electrodynamics, the scattering of an electron by a muon in the presence of a circularly polarized monochromatic laser field is investigated theoretically in the first Born approximation. The expressions for the amplitude and the differential cross section (DCS) are derived analytically by adopting the Furry picture approach in which the calculations are carried out using exact relativistic Dirac-Volkov functions. We begin by studying the process taking into account the relativistic dressing of only the electron without muon. Then, in order to reveal the effect of the muon dressing, we fully consider the relativistic dressing of the electron and muon together in the initial and final states. As a result, the DCS is significantly reduced by the laser field. We find that the effect of laser-dressing of muon becomes noticeable at laser field strengths greater than or equal to

10

9

 

V cm

−
1

and therefore must be taken into account. The influence of the laser field strength and frequency on the DCS and multiphoton process is revealed. An insightful comparison with the laser-free results is also included.
Yield enhancement of elliptical high harmonics driven by bicircular laser pulses
Authors: Zhang Xiaofan , Zhu Xiaosong
Published: April 2022

We theoretically investigate the yield enhancement of elliptical high harmonics in the interaction of molecules with bicircular laser pulses by solving the time-dependent Schrödinger equation. It is shown that by adjusting the relative intensity ratio of the two bicircular field components in specific ranges the yield of the molecular high harmonics for the plateau and cutoff regions can be respectively enhanced. To analyze this enhancement phenomenon, we calculate the weights of the electron classical trajectories. Additionally, we also study the ellipticity distribution of harmonics for different intensity ratios. We find that these enhanced harmonics are elliptically polarized, which we mainly attribute to the recombination dipole moment of the major weighted trajectories. These enhanced elliptical extreme ultraviolet and soft x-ray radiations may serve as essential tools for exploring the ultrafast dynamics in magnetic materials and chiral media.
Analysis of refraction and scattering image artefacts in x-ray analyzer-based imaging
Authors: Zhao Li-Ming , Wang Tian-Xiang , Ma Run-Kang , Gu Yao , Luo Meng-Si , Chen Heng , Wang Zhi-Li , Ge Xin
Published: April 2022

X-ray analyzer-based imaging (ABI) is a powerful phase-sensitive technique that can provide a wide dynamic range of density and extract useful physical properties of the sample. It derives contrast from x-ray absorption, refraction, and scattering properties of the investigated sample. However, x-ray ABI setups can be susceptible to external vibrations, and mechanical imprecisions of system components, e.g., the precision of motor, which are unavoidable in practical experiments. Those factors will provoke deviations of analyzer angular positions and hence errors in the acquired image data. Consequently, those errors will introduce artefacts in the retrieved refraction and scattering images. These artefacts are disadvantageous for further image interpretation and tomographic reconstruction. For this purpose, this work aims to analyze image artefacts resulting from deviations of analyzer angular positions. Analytical expressions of the refraction and scattering image artefacts are derived theoretically and validated by synchrotron radiation experiments. The results show that for the refraction image, the artefact is independent of the sample’s absorption and scattering signals. By contrast, artefact of the scattering image is dependent on both the sample’s refraction and scattering signals, but not on absorption signal. Furthermore, the effect of deviations of analyzer angular positions on the accuracy of the retrieved images is investigated, which can be of use for optimization of data acquisition. This work offers the possibility to develop advanced multi-contrast image retrieval algorithms that suppress artefacts in the retrieved refraction and scattering images in x-ray analyzer-based imaging.
An image encryption algorithm based on spatiotemporal chaos and middle order traversal of a binary tree
Authors: Su Yining , Wang Xingyuan , Lin Shujuan
Published: April 2022

This paper proposes an image encryption algorithm based on spatiotemporal chaos and middle order traversal of a binary tree. Firstly, other programming software is used to perform the middle order traversal, and the plaintext image is sorted according to the middle order traversal sequence on the permutation. Secondly, the chaotic sequence is generated using the coupled map lattice to set the chaotic interference value. Finally, the XOR operation between the adjacent pixel values of the replacement image is completed to generate the ciphertext matrix. The simulation and experimental results show that the proposed algorithm can resist typical attacks and has good robustness.
High resolution spectroscopy of Rb in magnetic field by far-detuning electromagnetically induced transparency
Authors: Xu Zi-Shan , Wang Han-Mu , Cai Ming-Hao , You Shu-Hang , Liu Hong-Ping
Published: April 2022

We have presented a high resolution spectroscopy of Rb in magnetic field by far-detuning electromagnetically induced transparency (EIT). The EIT spectrum in the Ξ-type configuration is usually companied by a double resonance optical pumping (DROP) due to the strong optical coupling between the two upper states, leading to the spectral lines seriously deformed and widely broadened for complex relaxation processes in DROP. Here we demonstrate a high resolution spectroscopy by far-detuning EIT for 87Rb 5S1/2 → 5P
3/2 → 5D
5/2 in magnetic fields. The method of far-detuning eliminates the relaxation in DROP to the most extent and decreases the spectral linewidth from more than 20 MHz down to its natural linewidth limit (6 MHz). The deformation of the spectral lines also disappears and the observed spectra are well in accordance with the theoretical calculation. Our work shows that far-detuning EIT is a reliable high resolution spectroscopic method when the relaxation in DROP cannot be neglected, especially for the case of transition to low excited states.
Evolution of microstructure, stress and dislocation of AlN thick film on nanopatterned sapphire substrates by hydride vapor phase epitaxy
Authors: Wang Chuang , Gao Xiao-Dong , Li Di-Di , Chen Jing-Jing , Chen Jia-Fan , Dong Xiao-Ming , Wang Xiaodan , Huang Jun , Zeng Xiong-Hui , Xu Ke
Published: April 2022

A crack-free AlN film with 4.5 μm thickness was grown on a 2-inch hole-type nano-patterned sapphire substrates (NPSSs) by hydride vapor phase epitaxy (HVPE). The coalescence, stress evolution, and dislocation annihilation mechanisms in the AlN layer have been investigated. The large voids located on the pattern region were caused by the undesirable parasitic crystallites grown on the sidewalls of the nano-pattern in the early growth stage. The coalescence of the c-plane AlN was hindered by these three-fold crystallites and the special triangle void appeared. The cross-sectional Raman line scan was used to characterize the change of stress with film thickness, which corresponds to the characteristics of different growth stages of AlN. Threading dislocations (TDs) mainly originate from the boundary between misaligned crystallites and the c-plane AlN and the coalescence of two adjacent c-plane AlN crystals, rather than the interface between sapphire and AlN.
Observation of quadratic magnetoresistance in twisted double bilayer graphene
Authors: Chu Yanbang , Liu Le , Ji Yiru , Tian Jinpeng , Wu Fanfan , Tang Jian , Yuan Yalong , Zhao Yanchong , Zan Xiaozhou , Yang Rong , Watanabe Kenji , Taniguchi Takashi , Shi Dongxia , Yang Wei , Zhang Guangyu
Published: April 2022

Magnetoresistance (MR) provides rich information about Fermi surface, carrier scatterings, and exotic phases for a given electronic system. Here, we report a study of the magnetoresistance for the metallic states in twisted double bilayer graphene (TDBG). We observe quadratic magnetoresistance in both Moiré valence band (VB) and Moiré conduction band (CB). The scaling analysis shows validity of Kohler’s rule in the Moiré valence band. On the other hand, the quadratic magnetoresistance appears near the halo structure in the Moiré conduction band, and it violates Kohler’s rule, demonstrating the MR scaling related to band structure in TDBG. We also propose an alternative scaling near the halo structure. Further analysis implies that the observed quadratic magnetoresistance and alternative scaling in conduction band are related to the halo boundary. Our results may inspire investigation on MR in twisted 2D materials and provide new knowledge for MR study in condensed matter physics.
Enhancement of the second harmonic generation from monolayer WS2 coupled with a silica microsphere
Authors: Qi Xiao-Zhuo , Ren Xi-Feng
Published: April 2022

Monolayer transition metal dichalcogenides (TMDs) are widely used for integrated optical and photoelectric devices. Owing to their broken inversion symmetry, monolayer TMDs have a large second-order optical nonlinearity. However, the optical second-order nonlinear conversion efficiency of monolayer TMDs is still limited by the interaction length. In this work, we theoretically study the second harmonic generation (SHG) from monolayer tungsten sulfide (WS2) enhanced by a silica microsphere cavity. By tuning the position, size, and crystal orientation of the material, second-order nonlinear coupling can occur between the fundamental pump mode and different second harmonic cavity modes, and we obtain an optimal SHG conversion efficiency with orders of magnitude enhancement. Our work demonstrates that the microsphere cavity can significantly enhance SHG from monolayer 2D materials under flexible conditions.
Rogue waves of a (3+1)-dimensional BKP equation
Authors: Yuan Yu-Qiang , Wu Xiao-Yu , Du Zhong
Published: April 2022

We investigate certain rogue waves of a (3+1)-dimensional BKP equation via the Kadomtsev–Petviashili hierarchy reduction method. We obtain semi-rational solutions in the determinant form, which contain two special interactions: (i) one lump develops from a kink soliton and then fuses into the other kink one; (ii) a line rogue wave arises from the segment between two kink solitons and then disappears quickly. We find that such a lump or line rogue wave only survives in a short time and localizes in both space and time, which performs like a rogue wave. Furthermore, the higher-order semi-rational solutions describing the interaction between two lumps (one line rogue wave) and three kink solitons are presented.
Continuous 2D trajectory decoding from attempted movement: across-session performance in able-bodied and feasibility in a spinal cord injured participant
Authors: Pulferer Hannah S , Ásgeirsdóttir Brynja , Mondini Valeria , Sburlea Andreea I , Müller-Putz Gernot R
Published: April 2022

Objective. In people with a cervical spinal cord injury (SCI) or degenerative diseases leading to limited motor function, restoration of upper limb movement has been a goal of the brain-computer interface field for decades. Recently, research from our group investigated non-invasive and real-time decoding of continuous movement in able-bodied participants from low-frequency brain signals during a target-tracking task. To advance our setup towards motor-impaired end users, we consequently chose a new paradigm based on attempted movement. Approach. Here, we present the results of two studies. During the first study, data of ten able-bodied participants completing a target-tracking/shape-tracing task on-screen were investigated in terms of improvements in decoding performance due to user training. In a second study, a spinal cord injured participant underwent the same tasks. To investigate the merit of employing attempted movement in end users with SCI, data of the spinal cord injured participant were recorded twice; once within an observation-only condition, and once while simultaneously attempting movement. Main results. We observed mean correlations well above chance level for continuous motor decoding based on attempted movement in able-bodied participants. Additionally, no global improvement over three sessions within five days, both in sensor and in source space, could be observed across all participants and movement parameters. In the participant with SCI, decoding performance well above chance was found. Significance. No presence of a learning effect in continuous attempted movement decoding in able-bodied participants could be observed. In contrast, non-significantly varying decoding patterns may promote the use of source space decoding in terms of generalized decoders utilizing transfer learning. Furthermore, above-chance correlations for attempted movement decoding ranging between those of observation only and executed movement were seen in one spinal cord injured participant, suggesting attempted movement decoding as a possible link between feasibility studies in able-bodied and actual applications in motor impaired end users.
Pattern Inversion as a Pattern Recognition Method for Machine Learning
Authors: Mikhailov Alexei , Karavay Mikhail
Published: April 2022

Artificial neural networks use a lot of coefficients that take a great deal of computing power for their adjustment, especially if deep learning networks are employed. However, there exist coefficients-free extremely fast indexing-based technologies that work, for instance, in Google search engines, in genome sequencing, etc. The paper discusses the use of indexing-based methods for pattern recognition. It is shown that for pattern recognition applications such indexing methods replace with inverse patterns the fully inverted files, which are typically employed in search engines. Not only such inversion provides automatic feature extraction, which is a distinguishing mark of deep learning, but, unlike deep learning, pattern inversion supports almost instantaneous learning, which is a consequence of absence of coefficients. The paper discusses a pattern inversion formalism that makes use on a novel pattern transform and its application for unsupervised instant learning. Examples demonstrate a view-angle independent recognition of three-dimensional objects, such as cars, against arbitrary background, prediction of remaining useful life of aircraft engines, and other applications. In conclusion, it is noted that, in neurophysiology, the function of the neocortical mini-column has been widely debated since 1957. This paper hypothesizes that, mathematically, the cortical mini-column can be described as an inverse pattern, which physically serves as a connection multiplier expanding associations of inputs with relevant pattern classes.
Development of a Face Identification System’s Prototype
Authors: Tkachenko S N , Pichugina A V , Shpilevoy A A , Zakharov A I
Published: April 2022

The paper considers the development of a prototype of a user identification system by face. The system uses face recognition technology built on base points. Neural networks and machine learning methods are used for development of this system. The system is designed using principal component analysis, support vector machine classifier and deep artificial neural networks. We have developed a user-friendly interface. The system has been verified on test images and has been shown sufficient accuracy for identifying people by their photos.
Application of Algorithm of Fuzzy Rule Conclusions in Determination of Animal’s Diseases
Authors: Primova H A , Mukhamedieva D T , Safarova L
Published: April 2022

Today, the detection of non-communicable animal diseases, the analysis of experimental data and the construction of a mathematical model is one of the main problems. In the article a method for determining the type of disease in cattle using a fuzzy inference rule algorithm is discussed. In our country, diseases with ketosis, microelementosis, ostradistraphia and secondary ostradithraphy in livestock, especially cattle, are determined by errors in determining the type of disease due to their similar symptoms. Since the symptoms of these diseases are interrelated and one of them can cause the other, solving this problem using fuzzy rule algorithms helps to reduce the error in determining the type of disease.
Offloading Decision Making for Workflow Applications Using an Enhanced Genetic Algorithm in the Edge Environment
Authors: Balasubramanian S. , Meyyappan T.
Published: April 2022

Edge computing is an environment suitable for processing the workflow applications produced by the IoT devices to reduce time and energy consumption. The execution of the workflow task in the Cloud computing environment increases the consumption of both time and energy. In order to solve this issue, this paper proposes a new approach, namely, Decision making Regarding the offloading of A subset of the Workflow application (DRAW). In the DRAW approach, selecting the destination environment for executing the subset of the workflow application occurs in the Edge environment. The DRAW uses the genetic algorithm for offloading the subset to minimize the objective factors, including total execution time and energy consumption. It equally prioritizes both the objective factors for improving the execution of the subset in the Cloud environment using the improved genetic algorithm. The DRAW approach improves the genetic algorithm by removing its traditional limitations and produces an effective possible solution in terms of better offspring. Finally, the algorithm stops by attaining the best solution from the possible solutions. Thus, the implementation results show that the DRAW approach significantly outperforms the existing approach by minimizing execution time and energy consumption.
Stock Market Prediction Based on Time-frequency Analysis and Convolutional Neural Network
Authors: Jia Dandi , Gao Qiang , Deng Hui
Published: April 2022

Recently, researchers have shown an increased interest in stock market prediction with neural networks. Stock market is affected by a multiplicity of factors with different active periods, thus financial time series possess multiscale frequency characteristics, which can be exploited to facilitate prediction of stock market. In this paper, we propose a stock market prediction model combining time-frequency analysis and convolutional neural network (CNN), in which the influence extent of different frequency components has been considered. We transform original financial time series into the spectrogram reflecting time-localized frequency information by short-time Fourier transform (STFT). The 2-dimensional time-frequency feature is obtained from the spectrogram by frequency bands extraction, which is then pre-weighted and input into CNN to forecast the future price change. The frequency bands extraction and pre-weight are set according to the frequency influence. The results of experiments on Shanghai Composite Index show that the proposed model with frequency bands extraction considering frequency influence achieves a 4% relative decrease in mean absolute error (MAE) compared with that does not consider the frequency influence. Moreover, the pre-weight gives an additional 3% relative decrease of MAE.
Pedestrian’s Abnormal Behaviour Detection Based on Machine Vision
Authors: Zhao Rongyong , Jia Ping , Yanwang  , Zhu Wenjie , Li Cuiling , Ma Yunlong
Published: April 2022

It is significant to automatically analyse video sequences for timely and accurate detection of abnormal pedestrian behaviour by using computer vision and analysis technology in public places. To realize the real-time monitoring of abnormal behaviour, this study uses a hybrid behaviour detection model based on the colour characteristics of the pixels and the gradient characteristics of the pixels mathematically. According to the hybrid behaviour detection model, the criterion of abnormal behaviour of the same pedestrian based on two frames of video images is proposed. This is conducive to realizing early awareness of emergencies caused by abnormal behaviours and taking early warning measures, reducing casualties, and maintaining public safety and social stability.
Research and Implementation of Flow Pattern Recognition for Gas-liquid Two-phase Flows Based on GoogLeNet
Authors: Yuan Jiaxin , Kan Zhe
Published: April 2022

In order to solve the flow pattern recognition problem of gas-liquid two-phase flow in pipelines, this paper uses high-speed photography to sample the flow patterns of transparent pipe sections and combines the GoogLeNet convolutional neural network model under migration learning to implement a flow pattern recognition method with small samples. In this paper, the GoogLeNet Inception V1 network is used, and the convolutional layer and the pooling layer weights parameters obtained from its training on the imageNet dataset are retained, and the flow pattern samples obtained on the gas-liquid two-phase flow experimental platform are used to train the network model. The recognition accuracy was 98.37% with a training set of 400 and a test set of 100 samples of each flow type. The convolutional neural network directly uses images as data input without operations such as image pre-processing and feature extraction, and its unique fine-grained feature extraction enables the recognition of images by convolutional neural networks at a nearly human level.