bluuebunny/crossref_metadata_2025 huggingface dataset:
Imaging of Dentate Nucleus Pathologies: A Case Series
Authors: M.K Usha Chowdary , S.V Naveen Prasad , Gudla Satish , Bhuma Vengamma
Published: January 2022

The dentate nucleus is the largest cerebellar nucleus, and it controls cognition and voluntary movement. It is found in each cerebellar hemisphere medially and posterolateral to the lateral ventricle. Pathologies of the dentate nucleus can be detected using computed tomography and magnetic resonance imaging of the brain. Here, we present a case series of seven different dentate nucleus diseases and their neuroimaging findings recovered from archives of our institution.
Study of Clinical Features and Diagnosis Pattern of Duchene Muscular Dystrophy in Southern India
Authors: Sattenapalli Nigama Chandra , Areti Anka Rao , G. S.N. Koteswara Rao , Kulandaivelu Uma Sankar , Alavala Rajasekhar Reddy , Manne Ravi
Published: January 2022

Background Duchene muscular dystrophy (DMD) is an X-linked progressive muscle disorder that is characterized by proximal muscle weakness followed by a premature death in young boys. There is a low index of reports on diagnosis ratio and clinical features in Southern India.

Objective The present study aimed to conduct an observational survey on preliminary analysis, family history, associated complaints, and diagnosis ratio of DMD in southern regions of India.

Materials and Methods A systematic observation and survey were conducted on clinically confirmed DMD patients registered between 2019 and 2021 through the questionnaire. The questionnaire and pattern of study were identified by exploring published and unpublished studies available from electronic databases and critical assessment criteria considered by physicians. Preliminary analysis such as onset criteria, motor difficulties, milestone delay; family history and consanguinity analysis; chief complaints (ambulatory status, lordosis, respiratory, and cardiac outcomes), associated complaints such as enlarged tongue, oral hygiene, behavioral problems; and other similar parameters were studied. An assessment of the diagnosis rate and pattern was performed.

Statistical analysis The data were reviewed and interpreted through statistical methods mean ± standard deviation represented as a percentage.

Results In total, 400 DMD patients were included and 250 participated in the study. The onset age group was 2 to 5 years in 37% of the population. Milestone delay was seen in 86%; consanguinity marriage of parents was reported in 39%. Frequent falls were reported in 62% in 5 to 8 years old group. Wheelchair status was reported in 65% in 9 to 12 years old. Cervical and lumbar lordoses were seen in 57 and 69%, respectively, in above 13 years old. Respiratory and cardiac complications were 88 and 78% reported in above 13 years old, respectively. Other major associated complaints such as enlarged tongue were reported in 79%. Fifty-one percent underwent genetic diagnosis and 79% of the population underwent serum creatine phosphokinase (CPK) analysis for the confirmation of DMD.

Conclusion In this study population of South India, milestone delay was a major observation. Although there was a slight margin, family history shows “no blood relation among parents” in the majority of the study population. Chief complaints were predominantly severe above 13-year age group population. Serum CPK was the first choice for the first investigation, which is followed by a genetic diagnosis.
Developing low cost, efficient magnetic refrigeration down to 0.2 K
Authors: Piccone Ashley
Published: January 2022

Magnetic refrigerators made of YbCu4Ni could be used for condensed matter physics, superconducting circuits, cosmic ray detectors.
Magnetic nanoparticle relaxation processes key for medical imaging techniques
Authors: Piccone Ashley
Published: January 2022

Separating Brownian and Néel relaxation mechanisms by timescale using advanced technology.
Accounting for mechanobiology to model and treat osteoarthritis
Authors: Piccone Ashley
Published: January 2022

Models of joints should include cartilage and underlying bone, inflammation, and mechanical loading.
Improvement in metal vapor laser performance with reduction in localized electric field at electrodes
Authors: Singh Dheeraj K. , Dikshit B. , Mukherjee Jaya , Rawat V. S.
Published: January 2022

Electrode geometry plays a vital role in metal vapor laser performance. It has been observed that by modifying the electrode geometry, the electric field enhancement near the electrode can be reduced. Reduction in the localized electric field causes reduction in the phantom current in the metal vapor laser. On replacing the electrode geometry having eight pins with an electrode having the zero-pin configuration, a 10% decrease in the phantom current and a 23% increase in optical output power are observed. The low phantom current is responsible for higher efficiencies, large specific average output power, and improved beam characteristics of that laser in reference to a conventional copper vapor laser. It was also observed that reduction in field enhancement causes reduction in the thermal loading at the cathode fall and in the probability of thermal instability, thereby improving the discharge stability and jitter in metal vapor lasers. This simple and effective technique can also be applied to the systems requiring high current and high-volume stable discharge.
Influence of reflections on mode-competition processes in a high-power multimode gyrotron
Authors: Melnikova M. M. , Ryskin N. M.
Published: January 2022

Reflection of radiation from an output window may strongly affect operation of a gyrotron. In recent years, the control of gyrotron radiation by reflection has become a subject of active study. In this paper, we study the effect of reflection on mode competition in a multimode gyrotron. We consider the interaction of five modes with neighboring azimuthal indexes in a gyrotron with a fixed Gaussian axial field profile. We assume the mode spectrum to be nearly equidistant and set the spectral density parameter value as in high-power gyrotrons used for plasma heating. We analyze the domain of stability of the operating mode on the cyclotron frequency mismatch–normalized beam current parameter plane with and without the reflections. The possibility of suppressing spurious sideband modes and expanding the single-mode oscillation zone of the operating mode by injecting the reflected signal is demonstrated by numerical simulation. The most advantageous situation is when the designed mode is matched with the output window while the reflections of the parasitic modes are rather strong and the reflected waves return into the gyrotron resonator in the adverse phase reducing the Q-factors of the parasitic modes.
Acoustic focusing and imaging via phononic crystal and acoustic metamaterials
Authors: Ma Fuyin , Huang Zhen , Liu Chongrui , Wu Jiu Hui
Published: January 2022

The effective operation of certain electronic, medical, industrial, and testing equipment relies on high-quality focusing and imaging capability, which also plays a vital role in the field of wave physics. Therefore, continuously improving the resolution capacity is essential. However, in a homogeneous medium dominated by the diffraction limit, the best resolution for wave focusing and imaging could only reach half the wavelength corresponding to the lowest operating frequency, significantly hindering the relevant application value. The development of phononic crystals (PCs) and acoustic metamaterials (AMMs) has realized sub-wavelength focusing and super-resolution imaging and attracted increasing research attention in physics, mechanics, engineering, and biomedical science. This Tutorial explained the basic principles and traditional methods of acoustic focusing and imaging. Then, the implementation principles and related research progress of sub-wavelength focusing and super-resolution imaging based on artificial acoustic devices, including but not limited to PCs and AMMs, were systematically discussed. Moreover, a method was introduced to realize sub-wavelength or sub-diffraction focusing by integrating these artificial devices into the time-reversal procedure. Finally, the potential development trends and practical application prospects were presented.
Unsteady pulsating flowfield over spiked axisymmetric forebody at hypersonic flows
Authors: Sugarno Mohammed Ibrahim , Sriram R. , Karthick S. K. , Jagadeesh Gopalan
Published: January 2022

The paper gives experimental observations of the hypersonic flow past an axisymmetric flat-face cylinder with a protruding sharp-tip spike. Unsteady pressure measurements and high-speed schlieren images are performed in tandem on a hypersonic Ludwieg tunnel at a freestream Mach number of M∞=8.16 at two different freestream Reynolds numbers based on the base body diameter (ReD=0.76×106 and 3.05×106). The obtained high-speed images are subjected further to modal analysis to understand the flow dynamics parallel to the unsteady pressure measurements. The protruding spike of length to base body diameter ratio of [l/D]=1 creates a familiar form of an unsteady flowfield called “pulsation.” Pressure loading and fluctuation intensity at two different ReD cases are calculated. A maximum drop of 98.24% in the pressure loading and fluctuation intensity is observed between the high and low ReD cases. Due to the low-density field at low ReD case, almost all image analyses are done with the high ReD case. Based on the analysis, a difference in the pulsation characteristics is noticed, which arises from two vortical zones, each from a system of two “λ” shocks formed during the “collapse” phase ahead of the base body. The interaction of shedding vortices from the λ-shocks' triple-points, along with the rotating stationary waves, contributes to the asymmetric high-pressure loading and the observation of shock pulsation on the flat-face cylinder. The vortical interactions forming the second dominant spatial mode with a temporal mode carry a dimensionless frequency (f2D/u∞≈0.34) almost twice that of the fundamental frequency (f1D/u∞≈0.17). The observed frequencies are invariant irrespective of the ReD cases. However, for the high-frequency range, the spectral pressure decay is observed to follow an inverse and −7/3 law for the low and high ReD cases, respectively.
Mobilities of two spherical particles immersed in a magneto-micropolar fluid
Authors: El-Sapa Shreen , Faltas M. S.
Published: January 2022

In this article, we consider the slow quasi-steady translational motion of two spherical particles immersed in an unbounded magneto-micropolar fluid. The micropolar fluid is allowed to slip and spin slip at the surfaces of the particles. The two particles are of the same material and may differ in radius. The particles migrate along the line connecting their centers with different velocities (or indifferent applied forces). The solutions are found under the conditions of low Reynolds numbers. The governing differential equations are solved semi-analytically in conjunction with the boundary collocation techniques. The interaction effects between the particles are evaluated through the magneto-micropolar mobility coefficients. Values of the mobility coefficients are tabulated and represented graphically and then discussed for various values of the relevant parameters. In general, it is found that the effect of the micropolarity parameter with the magnetic Hartmann number is significant. The convergence and accuracy of our collocation scheme for the normalized drag force acting on each particle for different values of spacing distance and Hartmann number is shown in Table I. Results of the normalized drag force agree very well with the existing solutions in the absence of the transverse magnetic field, which was published in the work of Sherief et al., “Interaction between two rigid spheres moving in a micropolar fluid with slip surfaces,” J. Mol. Liq. 290, 111165 (2019) and, also for the case of Newtonian fluid, was published in the work of Shreen and Alsudais, “Effect of magnetic field on the motion of two rigid spheres embedded in porous media with slip surfaces,” Eur. Phys. J. E 44, 1 (2021).
Topology and cavitation number characteristics of the gaseous jet-induced tail cavity under co-flow
Authors: Yang Qian , Xu Hao , Li Yiguo , Zhang Wenhui , Wei Yingjie , Wang Cong
Published: January 2022

The tail cavity as induced by submerged gaseous jets on the bottom of axisymmetric vehicles is studied in a water tunnel over Froude numbers, which denote co-flow velocities, between 4.8 < Fr < 16.0, and the jet stagnation to ambient pressure ratio in a convergent–divergent nozzle between 1.7 < p0/p∞ < 14.5. The shadowgraph topology of the induced tail cavity falls into three consecutive categories on the regime map: intact cavity, partially broken cavity (PBC), and pulsating foamy cavity. Both the Fr and p0/p∞ are essential drivers for the topology and length of the tail cavity within the current scope. The length of PBC holds a logarithmic relationship to p0/p∞. The fluctuation intensity of the cavitation number is under heavy influence from Fr and p0/p∞ and is regarded as a direct and reliable measurement of jet/closure interaction intensity. Under high Fr, the Rayleigh–Taylor instability is dominant at the cavity surface, which leads to a significant amount of bubble shedding and adds to the total cavity gas leakage. From the perspective of the vehicle, the characteristics of its bottom pressure depend on the cavity regime. The characteristics of jet-induced tail cavity established in the presented study should be helpful for the design and control of submarine vehicles propelled by rockets and supersonic jets.
Through-skin pilot-hole detection and localization with a mechanically translatable atomic magnetometer
Authors: Maddox Benjamin , Cohen Yuval , Renzoni Ferruccio
Published: January 2022

We demonstrate through-skin electromagnetic induction imaging of pilot-holes in an aluminum block concealed by a 0.41 mm thick aluminum shield with a 1.49 kg mechanically translatable radio frequency atomic magnetometer. The pilot-holes are identified and localized with submillimeter accuracy both with and without the Al shield. We utilize a dual-frequency technique to isolate the image of the target while removing the effect of the shielding from the image. Imaging accuracy is shown to be robust in a range of different operating conditions and immune to the effect of a thermal insulator between the shielding and the target. The approach introduced here finds direct application in aircraft wing manufacture and is competitive with existing approaches.
The synthetic artificial stem cell (SASC): Shifting the paradigm of cell therapy in regenerative engineering
Authors: Shah Shiv , Esdaille Caldon Jayson , Bhattacharjee Maumita , Kan Ho-Man , Laurencin Cato T.
Published: January 2022

Significance

This paper presents the synthetic artificial stem cell (SASC) system: a versatile therapy which provides the ability to tailor paracrine responses of different cells and provide a more potent regenerative effect for targeted tissues. Upon challenging the SASC system against an osteoarthritis model, we demonstrate that the factors combined tailored for chondrogenesis have a potent antiinflammatory and chondroprotective effect. This paper also demonstrates the in vivo capacity of SASC to attenuate proteoglycan depletion in the cartilage extracellular matrix while also improving biomechanical properties of the resulting cartilage. We report the first of many applications of the SASC system, which provides a promising step toward clinical translation of a minimally immunogenic stem cell with many commercial advantages over its biological counterpart.
Effective potential of scalar-tensor gravity with quartic self-interaction of scalar field
Authors: Arbuzov A , Latosh B , Nikitenko A
Published: January 2022

One-loop effective potential of scalar-tensor gravity with a quartic scalar field self-interaction is evaluated up to first post-Minkowskian order. The potential develops an instability in the strong field regime which is expected from an effective theory. Depending on model parameters the instability region can be exponentially far in a strong field region. Possible applications of the model for inflationary scenarios are highlighted. It is shown that the model can enter the slow-roll regime with a certain set of parameters.
Assessing the compact-binary merger candidates reported by the MBTA pipeline in the LIGO–Virgo O3 run: probability of astrophysical origin, classification, and associated uncertainties
Authors: Andres N , Assiduo M , Aubin F , Chierici R , Estevez D , Faedi F , Guidi G M , Juste V , Marion F , Mours B , Nitoglia E , Sordini V
Published: January 2022

We describe the method used by the multi-band template analysis (MBTA) pipeline to compute the probability of astrophysical origin, p
astro, of compact binary coalescence candidates in LIGO–Virgo data from the third observing run (O3). The calculation is performed as part of the offline analysis and is used to characterize candidate events, along with their source classification. The technical details and the implementation are described, as well as the results from the first half of the third observing run (O3a) published in GWTC-2.1. The performance of the method is assessed on injections of simulated gravitational-wave signals in O3a data using a parameterization of p
astro as a function of the MBTA combined ranking statistic. Possible sources of statistical and systematic uncertainties are discussed, and their effect on p
astro quantified.
Γ-convergence of Onsager–Machlup functionals: II. Infinite product measures on Banach spaces
Authors: Ayanbayev Birzhan , Klebanov Ilja , Lie Han Cheng , Sullivan T J
Published: January 2022

We derive Onsager–Machlup functionals for countable product measures on weighted ℓ

p
subspaces of the sequence space

R

N

. Each measure in the product is a shifted and scaled copy of a reference probability measure on

R

that admits a sufficiently regular Lebesgue density. We study the equicoercivity and Γ-convergence of sequences of Onsager–Machlup functionals associated to convergent sequences of measures within this class. We use these results to establish analogous results for probability measures on separable Banach or Hilbert spaces, including Gaussian, Cauchy, and Besov measures with summability parameter 1 ⩽ p ⩽ 2. Together with part I of this paper, this provides a basis for analysis of the convergence of maximum a posteriori estimators in Bayesian inverse problems and most likely paths in transition path theory.
Consistency of Bayesian inference with Gaussian process priors for a parabolic inverse problem
Authors: Kekkonen Hanne
Published: January 2022

We consider the statistical non-linear inverse problem of recovering the absorption term f > 0 in the heat equation

∂

t

u
−

1

2

Δ
u
+
f
u
=
0

on

O
×

(

0
,
T

)

u
=
g

on

∂
O
×

(

0
,
T

)

u

(

⋅
,
0

)

=

u

0

on

O
,

where

O
∈

R

d

is a bounded domain, T < ∞ is a fixed time, and g, u
0 are given sufficiently smooth functions describing boundary and initial values respectively. The data consists of N discrete noisy point evaluations of the solution u

f
on

O
×

(

0
,
T

)

. We study the statistical performance of Bayesian nonparametric procedures based on a large class of Gaussian process priors. We show that, as the number of measurements increases, the resulting posterior distributions concentrate around the true parameter generating the data, and derive a convergence rate for the reconstruction error of the associated posterior means. We also consider the optimality of the contraction rates and prove a lower bound for the minimax convergence rate for inferring f from the data, and show that optimal rates can be achieved with truncated Gaussian priors.
Evaluation of the impact of abnormal grains on the performance of Sc0.15Al0.85N-based BAW resonators and filters
Authors: Liu Chen , Li Minghua , Chen Bangtao , Zhang Ying , Zhu Yao , Wang Nan
Published: January 2022

Sc
x
Al1−x
N is a promising piezoelectric material for radio frequency communication applications with excellent electro-acoustic properties. However, the growth of abnormally oriented grains is widely observed in the Sc doped AlN films deposited by sputtering. In this work, for the first time, the impact of the abnormal grains in the Sc0.15Al0.85N films on the performance of bulk acoustic wave resonators and filters is systematically evaluated by both simulations and measurements. The correlation between the device performance and the abnormal grain parameters, including the density, dimension, crystal orientation, growth height and the total volume of the abnormal grains, is evaluated and quantified. Simulation results show that the total volume of all abnormal grains in the whole device is the most critical factor among the parameters. Abnormal grains with randomly distributed parameters and around 6% total volume of the film can degrade the effective coupling coefficient of the resonator from 13.6% to 11%, leading to a 10.6% decrement of the filter bandwidth. Wafer-level device characterizations and measurements are performed, and the results are consistent with the simulations. This study provides a practical method for predicting the performance of the resonators and filters with abnormal grains, and a guideline for film quality evaluation.
Tunable and programmable topological valley transport in photonic crystals with liquid crystals
Authors: Zhao Yulin , Liang Feng , Wang Xiangru , Zhao Deshuang , Wang Bing-Zhong
Published: January 2022

Topological valley transport in photonic crystals (PCs) has attracted great attention owing to its edge modes immune to backscattering. However, flexibly dynamically controlling and reconfiguring the pathway of the topological one-way propagation is still challenging. Here, we propose a tunable and programmable valley PC structure based on nematic liquid crystals (LCs). Inversion symmetry breaking and topological transition are implemented through controlling the relative permittivity of the LC cells. Topological protection of valley edge states and valley-locked beam splitting are demonstrated. Moreover, the LC-based PC can be discretized to a number of supercells, each of which can be coded with ‘0’ or ‘1’. The wave propagation pathway can be dynamically reconfigured by programming different coding patterns.
Low-field magnetic anisotropy of Sr2IrO4
Authors: Nauman Muhammad , Hussain Tayyaba , Choi Joonyoung , Lee Nara , Choi Young Jai , Kang Woun , Jo Younjung
Published: January 2022

Magnetic anisotropy in strontium iridate (Sr2IrO4) is essential because of its strong spin–orbit coupling and crystal field effect. In this paper, we present a detailed mapping of the out-of-plane (OOP) magnetic anisotropy in Sr2IrO4 for different sample orientations using torque magnetometry measurements in the low-magnetic-field region before the isospins are completely ordered. Dominant in-plane anisotropy was identified at low fields, confirming the b axis as an easy magnetization axis. Based on the fitting analysis of the strong uniaxial magnetic anisotropy, we observed that the main anisotropic effect arises from a spin–orbit-coupled magnetic exchange interaction affecting the OOP interaction. The effect of interlayer exchange interaction results in additional anisotropic terms owing to the tilting of the isospins. The results are relevant for understanding OOP magnetic anisotropy and provide a new way to analyze the effects of spin–orbit-coupling and interlayer magnetic exchange interactions. This study provides insight into the understanding of bulk magnetic, magnetotransport, and spintronic behavior on Sr2IrO4 for future studies.
Three-dimensional graphene encapsulated hollow CoSe2-SnSe2 nanoboxes for high performance asymmetric supercapacitors
Authors: Li Kainan , Zheng Ke , Zhang Zhifang , Li Kuan , Bian Ziyao , Xiao Qian , Zhao Kuangjian , Li Huiyu , Cao Haijing , Fang Zebo , Zhu Yanyan
Published: January 2022

Construction of metal selenides with a large specific surface area and a hollow structure is one of the effective methods to improve the electrochemical performance of supercapacitors. However, the nano-material easily agglomerates due to the lack of support, resulting in the loss of electrochemical performance. Herein, we successfully design a three-dimensional graphene (3DG) encapsulation-protected hollow nanoboxes (CoSe2-SnSe2) composite aerogel (3DG/CoSe2-SnSe2) via a co-precipitation method coupled with self-assembly route, followed by a high temperature selenidation strategy. The obtained aerogel possesses porous 3DG conductive network, large specific surface area and plenty of reactive active sites. It could be used as a flexible and binder-free electrode after a facile mechanical compression process, which provided a high specific capacitance of 460 F g–1 at 0.5 A g–1, good rate capability of 212.7 F g−1 at 10 A g−1 The capacitance retention rate is 80% at 2 A g−1 after 5000 cycles due to the fast electron/ion transfer and electrolyte diffusion. With the as-prepared 3DG/CoSe2-SnSe2 as positive electrodes and the AC (activated carbon) as negative electrodes, an asymmetric supercapacitor (3DG/CoSe2-SnSe2//AC) was fabricated, which delivered a high specific capacity of 38 F g–1 at 1 A g–1 and an energy density of 11.89 Wh kg−1 at 749.9 W kg–1, as well as excellent cycle stability. This work provides a new method for preparing electrode material.
A conceptual model for changes in finger photoplethysmograph signals caused by hand posture and isothermic regulation
Authors: Keogh C , Drummond G B , Bates A , Mann J , Arvind D K
Published: January 2022

Objective. To observe changes in baseline position and pulsatile light absorbance (photoplethysmograph, PPG) in the finger-tip, by raising the hand above the horizontal plane in recumbent subjects. We applied current knowledge of the circulation to the finger-tip, particularly arteriovenous anastomoses (AVAs), and the physiology of the venous circulation. Approach.We studied healthy young volunteers in a quiet thermoneutral environment. A finger plethysmograph on the non-dominant hand recorded transmission of red and infra-red light, with observations expressed as absorbance to allow comparisons within and between subjects. Breathing movements were recorded unobtrusively to assess any effect on absorbance and the pulse amplitude of the signals. All body movements were passive: the study arm was elevated in a trough to about 40° above the horizontal plane. The following conditions were studied, each for 15 min, using the last 10 min for analysis: recumbent, study arm elevated, study arm horizontal, and both legs elevated by 40°. Main results. We found a substantial time-related effect, and considerable variation between subjects. Arm elevation reduced red light absorbance and increased the range of amplitudes of the PPG waveform: only in subjects with large absorbances, did waveform amplitude increase. Spontaneous, thermoregulatory decreases in absorbance were large and associated with decreases in waveform amplitude. Significance. Finger-tip vessels distend with blood and light absorbance increases when AVAs open. The vessels pulsate more strongly when the hand is raised: venous collapse allows the vessels to become more compliant. The postcapillary circulation is likely to be an important source of pulsation.
How reliable is measurement of posture during sleep: real-world measurement of body posture and movement during sleep using accelerometers
Authors: Smits Esther J , Salomoni Sauro , Costa Nathalia , Rodríguez-Romero Beatriz , Hodges Paul W
Published: January 2022

Objective. Understanding sleeping behaviours could improve prevention and treatment of sleep problems and associated health conditions. This study aimed to evaluate a method to assess body posture and movement during sleep using trunk-worn accelerometers for 28 nights. Approach. Participants (50 adults with low back pain (66% female); aged 32(±9) years) wore two activPAL-micro sensors (thigh, trunk) during their normal daily life for 28 consecutive days. Parameters related to body posture (e.g. time spent lying supine or prone) and movement (e.g. number of turns) during sleep were calculated for each night. Average values for each parameter were identified for different periods, the Spearman–Brown Prophecy Formula was used to estimate the minimum number of nights required to obtain a reliable estimate of each parameter, and repeatability of measures between different weeks was calculated. Main results. Participants spent 8.1(±0.8) h asleep and most time (44%) was spent in a supine posture. The minimum number of nights required for reliable estimates varied between sleep parameters, range 4–21 nights. The most stable parameters (i.e. requiring less than seven nights) were ‘average activity’, ‘no. of turns’, ‘time spent prone’, and ‘posture changes in the first hour’. Some measures differed substantially between weeks. Significance. Most sleep parameters related to body posture and movement require a week or more of monitoring to provide reliable estimates of behaviour over one month. Notably, one week may not reflect behaviour in another week, and the time varying nature of sleep needs to be considered.
An efficient and fast multi-band focused bioimpedance solution with EIT-based reconstruction for pulmonary embolism assessment: a simulation study from massive to segmental blockage
Authors: Nguyen Minh Duc , Duong Trong Luong , McEwan Alistair
Published: January 2022

Objective. Pulmonary embolism (PE) is an acute condition that blocks the perfusion to the lungs and is a common complication of Covid-19. However, PE is often not diagnosed in time, especially in the pandemic time due to complicated diagnosis protocol. In this study, a non-invasive, fast and efficient bioimpedance method with the EIT-based reconstruction approach is proposed to assess the lung perfusion reliably. Approach. Some proposals are presented to improve the sensitivity and accuracy for the bioimpedance method: (1) a new electrode configuration and focused pattern to help study deep changes caused by PE within each lung field separately, (2) a measurement strategy to compensate the effect of different boundary shapes and varied respiratory conditions on the perfusion signals and (3) an estimator to predict the lung perfusion capacity, from which the severity of PE can be assessed. The proposals were tested on the first-time simulation of PE events at different locations and degrees from segmental blockages to massive blockages. Different object boundary shapes and varied respiratory conditions were included in the simulation to represent for different populations in real measurements. Results. The correlation between the estimator and the perfusion was very promising (R = 0.91, errors <6%). The measurement strategy with the proposed configuration and pattern has helped stabilize the estimator to non-perfusion factors such as the boundary shapes and varied respiration conditions (3%–5% errors). Significance. This promising preliminary result has demonstrated the proposed bioimpedance method’s capability and feasibility, and might start a new direction for this application.
Dispersive MUSIC algorithm for Lamb wave phased array
Authors: Xu Caibin , Zuo Hao , Deng Mingxi
Published: January 2022

By controlling the excitation time delay on each element, the conventional phased array can physically focus signals transmitted by different elements on a desired point in turn. An alternative and time-saving strategy is that every element takes turns to transmit the excitation and the remaining elements receive the corresponding response signals, which is known as the full matrix capture (FMC) method for data acquisition, and then let the signals virtually focus on every desired point by post-processing technique. In this study, based on the FMC, a dispersive multiple signal classification (MUSIC) algorithm for Lamb wave phased array is developed to locate defects. The virtual time reversal is implemented to back propagate the wave packets corresponding to the desired focusing point and a window function is adopted to adaptively isolate the desired packets from the other components. Then those wave packets are forward propagated to the original focusing point at a constant velocity. For every potential focusing point and all receivers, the virtual array focuses the signals from all transmitters so as to obtain the focusing signals. The MUSIC algorithm with the obtained focusing signals is adopted to achieve Lamb wave imaging. Benefiting from the post-processing operations, the baseline subtraction as well as the estimation for the number of the scattering sources is no longer required in the proposed algorithm. Experiments on an aluminum plate with three artificial defects and a compact circular PZT array are implemented and the results demonstrate the efficacy of the proposed algorithm.
Dynamic resistance and total loss in a three-tape REBCO stack carrying DC currents in perpendicular AC magnetic fields at 77 K
Authors: Sun Yueming , Fang Jin , Sidorov Gennady , Badcock Rodney A , Long Nicholas J , Jiang Zhenan
Published: January 2022

In many high-temperature superconducting (HTS) applications, HTS-coated conductors carry a DC current under an external AC magnetic field. In such operating conditions, dynamic resistance will occur when the traversing magnetic flux across the HTS conductors. Consequently, AC loss within the superconductors is composed of the dynamic loss component arising from dynamic resistance and the magnetization loss component due to the AC external magnetic field. This AC loss is one of the critical issues for HTS applications, such as persistent current switches, flux pumps, and rotating machines. In this work, the dynamic resistance and the total loss in a three-tape HTS coated conductor stack were measured at 77 K under perpendicular AC magnetic fields up to 80 mT and DC currents (I
dc) up to the critical current (I
c). The stack was assembled from three serial-connected 4 mm wide Superpower wires. The measured dynamic resistance results for the stack were well supported by the results from 2D H-formulation finite element modelling (FEM) and broadly agree with the analytical values for stacks. The FEM analysis shows asymmetric transport DC current profiles in the central region of the superconductor. We attribute the result to the superposition of DC currents and the induced subcritical currents which explains why the measured magnetization loss values increase with DC current levels at low magnetic field. The onset of dynamic loss for the stack for low i (I
dc/I
c) values is much slower when compared to that of the single tape and hence the contribution of the dynamic loss component to the total loss in the stack is much smaller than that of the single tape. Dynamic loss in the stack becomes comparable to the magnetization loss at i = 0.5 and becomes greater than the magnetization loss at i = 0.7. Both magnetization loss and dynamic loss in the stack are smaller than those of the single tape due to shielding effects. The difference between the Q
total behaviours in the stack and single tape is due to the variation of the penetration depths of the stack and single tape at the different magnetic field amplitudes.
Jeans analysis with κ-deformed Kaniadakis distribution in f (R) gravity
Authors: He Ke-Rong
Published: January 2022

The influence of the κ-deformed Kaniadakis distribution on Jeans instability in the background of

f

R

gravity is investigated, the dispersion relation considering the κ-deformed Kaniadakis distribution is derived by exploiting the kinetic theory. The cases of high and low frequency perturbations are analyzed, respectively, it is found that the range of the unstable modes and the growth rates decrease with the increased distribution index κ in both of high and low frequency regime. Finally, based on the derivation of effective temperature, the relation between Jeans mass and temperature is studied, it is found that lower Jeans mass means that the system is more likely to collapse due to gravitational instability, the system is unstable for lower distribution index κ.
Kinematical modeling of circular and elliptical polarization of the polarized light via screw transformation
Authors: Özdemir Zehra
Published: January 2022

In this paper, it is shown that the motion of a polarized light wave in an optical fiber has a special meaning that relates the scalar and vector part of the dual quaternion to the kinematics concept of a screw. We describe the circular and elliptical polarization of a light wave according to how the electric field vector varies in a projection onto a plane perpendicular to the propagation direction using the Clifford algebra of the dual quaternion. Also, we determine the circular-Rytov curve (C

R
) and elliptical-Rytov curve (E

R
), which described the paths traced out by the tip of the electric field vector as it propagates in space, related to the polarization state of the electric field

E

. The elliptical and circular polarization states are expressed by using the four Stokes parameters and their matrix form. Furthermore, some motivating examples are given and visualized their images with the help of the MAPLE program.
The synergies between displacement damage creation and hydrogen presence: the effect of D ion energy and flux
Authors: Markelj Sabina , Pečovnik Matic , Schwarz-Selinger Thomas , Kelemen Mitja
Published: January 2022

In this work the synergism between displacement damage creation and presence of hydrogen isotopes was studied. Tungsten samples were irradiated by 10.8 MeV W ions with or without the presence of D ions with two different energies of 300 eV/D and 1000 eV/D and different temperatures. In order to compare the results obtained with different exposure parameters the samples were afterwards additionally exposed to D ions at 450 K to populate the created defects. By increasing the W irradiation time, ion flux and energy, the increase of D concentration and D retention was observed as measured by nuclear reaction analysis and thermal desorption spectroscopy. By fitting the D depth profiles and D desorption spectra by the rate equation code MHIMS-R we could see that additional fill-levels were populated with higher flux and ion energy which ends up in higher final D concentration and retention as compared to experiments with lower D flux and energy.
Stability and global sensitivity analysis of the transmission dynamics of malaria with relapse and ignorant infected humans
Authors: Mangongo Yves Tinda , Bukweli Joseph-Désiré Kyemba , Kampempe Justin Dupar Busili , Mabela Rostin Matendo , Munganga Justin Manango Wazute
Published: January 2022

In this paper we present a more realistic mathematical model for the transmission dynamics of malaria by extending the classical SEIRS scheme and the model of Hai-Feng Huo and Guang-Ming Qiu [21] by adding the ignorant infected humans compartment. We analyze the global asymptotically stabilities of the model by the use of the basic reproduction number R_0 and we prove that when R_0≦1, the disease-free equilibrium is globally asymptotically stable. That is malaria dies out in the population. When R_0>1, there exists a co-existing unique endemic equilibrium which is globally asymptotically stable. The global sensitivity analysis have been done through the partial rank correlation coefficient using the samples generated by the use of latin hypercube sampling method and shows that the most influence parameters in the spread of malaria are the proportion θ of infectious humans who recover and the recovery rate γ of infectious humans. In order to eradicate malaria, we have to decrease the number of ignorant infected humans by testing peoples and treat them. Numerical simulations show that malaria can be also controlled or eradicated by increasing the recovery rate γ of infectious humans, decreasing the number of ignorant infected humans and decreasing the average number n of mosquito bites.
The electric dipole response of even-even 154–164Dy isotopes
Authors: Quliyev H , Saygı N Demirci , Guliyev E , Kuliev A A
Published: January 2022

The excitation of pygmy dipole resonance (PDR) and giant dipole resonance (GDR) in even–even 154–164Dy isotopes is examined through quasiparticle random-phase approximation (QRPA) with the effective interactions that restore the broken translational and Galilean invariances. In each isotope, an electric response emerges by showing ample distribution at energies below and above 10 MeV. We, therefore, study the transition cross-sections and probabilities, photon strength functions, transition strengths, isospin character, and collectivity of the predicted E1 responses.
Use of symmetric sagnac dual-ring scheme for tunable single-mode erbium fiber laser
Authors: Chen Yi-Chi , Yeh Chien-Hung , Lin Wen-Piao , Liu Li-Hung , Ko Han-Shin , Lai Yu-Ting , Chow Chi-Wai
Published: January 2022

In this paper, an erbium-doped fiber (EDF) laser with symmetric Sagnac dual-ring scheme is experimentally studied to achieve tunable and stable continuous-wave (CW) single-longitudinal-mode (SLM) presentation. In the measurement, the obtained wavelength-tuning bandwidth can be reached from 1518.0 to 1578.0 nm based on a C-band EDF gain-medium. Moreover, the corresponding output power, optical signal to noise ratio (OSNR) and wavelength linewidth of the designed EDF laser are studied and performed simultaneously.
A musculoskeletal model driven by muscle synergy-derived excitations for hand and wrist movements
Authors: Zhao Jiamin , Yu Yang , Wang Xu , Ma Shihan , Sheng Xinjun , Zhu Xiangyang
Published: January 2022

Objective. Musculoskeletal model (MM) driven by electromyography (EMG) signals has been identified as a promising approach to predicting human motions in the control of prostheses and robots. However, muscle excitations in MMs are generally derived from the EMG signals of the targeted sensor covering the muscle, inconsistent with the fact that signals of a sensor are from multiple muscles considering signal crosstalk in actual situation. To identify more accurate muscle excitations for MM in the presence of crosstalk, we proposed a novel excitation-extracting method inspired by muscle synergy for simultaneously estimating hand and wrist movements. Approach. Muscle excitations were firstly extracted using a two-step muscle synergy-derived method. Specifically, we calculated subject-specific muscle weighting matrix and corresponding profiles according to contributions of different muscles for movements derived from synergistic motion relation. Then, the improved excitations were used to simultaneously estimate hand and wrist movements through musculoskeletal modeling. Moreover, the offline comparison among the proposed method, traditional MM and regression methods, and an online test of the proposed method were conducted. Main results. The offline experiments demonstrated that the proposed approach outperformed the EMG envelope-driven MM and three regression models with higher R and lower NRMSE. Furthermore, the comparison of excitations of two MMs validated the effectiveness of the proposed approach in extracting muscle excitations in the presence of crosstalk. The online test further indicated the superior performance of the proposed method than the MM driven by EMG envelopes. Significance. The proposed excitation-extracting method identified more accurate neural commands for MMs, providing a promising approach in rehabilitation and robot control to model the transformation from surface EMG to joint kinematics.
FB-CGANet: filter bank channel group attention network for multi-class motor imagery classification
Authors: Chen Jiaming , Yi Weibo , Wang Dan , Du Jinlian , Fu Lihua , Li Tong
Published: January 2022

Objective. Motor imagery-based brain–computer interface (MI-BCI) is one of the most important BCI paradigms and can identify the target limb of subjects from the feature of MI-based Electroencephalography signals. Deep learning methods, especially lightweight neural networks, provide an efficient technique for MI decoding, but the performance of lightweight neural networks is still limited and need further improving. This paper aimed to design a novel lightweight neural network for improving the performance of multi-class MI decoding. Approach. A hybrid filter bank structure that can extract information in both time and frequency domain was proposed and combined with a novel channel attention method channel group attention (CGA) to build a lightweight neural network Filter Bank CGA Network (FB-CGANet). Accompanied with FB-CGANet, the band exchange data augmentation method was proposed to generate training data for networks with filter bank structure. Main results. The proposed method can achieve higher 4-class average accuracy (79.4%) than compared methods on the BCI Competition IV IIa dataset in the experiment on the unseen evaluation data. Also, higher average accuracy (93.5%) than compared methods can be obtained in the cross-validation experiment. Significance. This work implies the effectiveness of channel attention and filter bank structure in lightweight neural networks and provides a novel option for multi-class motor imagery classification.
A Study on the Application and the Advancement of Deep Neural Network Algorithm
Authors: Song Jiulin , Chen Yansheng
Published: January 2022

Deep neural network is a new type of learning algorithm, which has both global and local aspects and performs well in pattern recognition and computational speed. In recent years, deep neural network algorithm has been widely used in scientific research and real life, but its complexity, parallelism and other characteristics lead it to be a very challenging and innovative research area. This study briefly introduces the basic principles and theoretical knowledge of deep neural network algorithms, and mainly discusses their applications and Advancement of feature extraction in the field.
Study on the BL Early Warning Model of Transmission Line Tower Based on KNN-SVM Algorithm
Authors: Hong Huawei , Wu Kaibin , Zhang Yunfeng
Published: January 2022

With the expansion of China’s power grid construction scale, the transmission line span are gradually improved, which also increases the risk of BL stroke on the transmission line. However, the traditional passive BL protection has many problems, such as weak pertinence and high investment cost, which can not meet the needs of social development. KNN can well describe the similarity measure between the two, which can effectively reduce the training samples. SVM can find the best compromise between model complexity and learning ability in small samples, which is a good sample training method. Through KNN - in-depth learning of the historical data of BL activities accumulated in the power grid, a supervised BL early warning model (hereinafter referred to as EWM) of transmission line can be trained. At the same time, the BL strike of transmission line tower (hereinafter referred to as TLT) has complex meteorological conditions, which requires comprehensive confirmation of various monitoring point parameters. Therefore, it is of great significance to study the BL EWM of TLT based on KNN-SVM algorithm. Firstly, this paper analyzes the KNN-SVM algorithm. Then, this paper establishes an EWM. Finally, this paper is verified.
Application Research of BP Neural Network Algorithm in Power Line Loss Calculation
Authors: Dai Su , Ma Yunlong , Wang Kai , Liu Bowen , Liu Changming
Published: January 2022

In recent years, it is still a difficult problem to calculate the line loss of distribution system. The main reason is that China’s power system data is not perfect, the components are huge, the management function does not exist, the network structure is directly connected. Therefore, reducing the loss rate of power system has become an urgent problem for energy companies to solve. Developing effective methods for line loss reduction evidence and line loss assessment requires careful calculation and analysis of line loss, which ultimately contributes to and guides line loss management.