bluuebunny/crossref_metadata_2025_split huggingface dataset:
Charge transport characteristic and charge stability enhancement mechanism of polyimide aerogel as an ultralight weight electret
Authors: Song Bo , Ren Ming , Hu Yizhuo , Wang Yue , Liu Yujie , Dong Ming 
Published: December 2022

Abstract
In this study, polyimide aerogel (PIA) is applied as an ultralight-weight and thermally stable electret material, meanwhile its charge transport characteristic and charge stability enhancement mechanism are investigated. It is found that PIA can exhibit excellent electret properties at 120 °C after corona charging at room temperature, and its charge stability acquires further promotion after charging at elevated temperatures or heat treatment, which far exceeds conventional polyimide-based electrets. Further research indicates that the outstanding charge retention characteristics of PIA originate from the enhanced local defect density, fast retrapping effect, weakened internal electric field by dipole polarization, and prolonged conduction path, which are inextricably linked to its porous structure. In addition, the high gas breakdown strength in the pores of PIA effectively limits the breakdown induced conductivity, thereby ensuring high space charge density and large piezoelectric response of PIA electrets. Considering the extremely low density and inherently excellent properties of polyimide substances, PIA may have promising prospects as an electret in the lightweight sensing and energy conversion devices at elevated temperatures.
Charged elastic rings: deformation and dynamics
Authors: Yao Zhenwei 
Published: December 2022

Abstract
We report the counter-intuitive instability of charged elastic rings, and the persistence of sinusoidal deformations in the lowest-energy configurations by the combination of high-precision numerical simulations and analytical perturbation calculation. We also study the dynamical evolution of the charged ring under random disturbance, and reveal the modulation of the dominant frequencies by the electrostatic force. The purely mechanical analysis of the classical ring system presented in this work yields insights into the subtlety of long-range forces in the organization and dynamics of matter.
High pressure phase transition and strength estimate in polycrystalline alumina during laser-driven shock compression
Authors: Hari Anirudh , Hari Rohit , Heighway Patrick G , Smith Raymond F , Duffy Thomas S , Sims Melissa , Singh Saransh , Fratanduono Dayne E , Bolme Cynthia A , Gleason Arianna E , Coppari Federica , Lee Hae Ja , Granados Eduardo , Heimann Philip , Eggert Jon H , Wicks June K 
Published: December 2022

Abstract
Alumina (Al2O3) is an important ceramic material notable for its compressive strength and hardness. It represents one of the major oxide components of the Earth’s mantle. Static compression experiments have reported evidence for phase transformations from the trigonal α-corundum phase to the orthorhombic Rh2O3(II)-type structure at ∼90 GPa, and then to the post-perovskite structure at ∼130 GPa, but these phases have yet to be directly observed under shock compression. In this work, we describe laser-driven shock compression experiments on polycrystalline alumina conducted at the Matter in Extreme Conditions endstation of the Linac Coherent Light Source. Ultrafast x-ray pulses (50 fs, 1012 photons/pulse) were used to probe the atomic-level response at different times during shock propagation and subsequent pressure release. At 107 ± 8 GPa on the Hugoniot, we observe diffraction peaks that match the orthorhombic Rh2O3(II) phase with a density of 5.16 ± 0.03 g cm−3. Upon unloading, the material transforms back to the α-corundum structure. Upon release to ambient pressure, densities are lower than predicted assuming isentropic release, indicating additional lattice expansion due to plastic work heating. Using temperature values calculated from density measurements, we provide an estimate of alumina’s strength on release from shock compression.
Oscillatory tribometry: transition from static to kinetic friction
Authors: Läuger Jörg 
Published: December 2022

Abstract
Oscillatory tribometry is presented as a new method for investigations on the transition from static friction to kinetic friction. The method distinguishes between purely elastic deformations and plastic frictional motions. Friction moduli are defined which are directly proportional to the stored and dissipated energy during an oscillation cycle. The elastic deformations are represented through the elastic friction modulus, which is directly proportional to the average elastic energy over an oscillation cycle, while the frictional motions yield the dissipation friction modulus, which is directly proportional to the average dissipated energy over an oscillation cycle. Energy dissipation in the static and boundary regime can be attributed to local dissolution of contact bonds or intermolecular adhesion bonds at the contact points, and thus to local slip. The ability to measure at very small sliding distances in oscillatory tribometer tests is a crucial prerequisite for such investigations. The methodology provides access to local friction phenomena at the intermolecular level while simultaneously measuring macroscopic samples. The application examples presented show that oscillatory tribometry on a highly sensitive rheometer is particularly valuable for applications such as dry contacts between polymers, elastomers or soft materials.
Coverage factors for efficient demonstration of compliance of low-frequency magnetic near-field exposures with basic restrictions
Authors: Xi Jingtian , Christ Andreas , Kuster Niels 
Published: December 2022

Abstract

Objective. Regulators require that wireless power transfer (WPT) systems and other strong magnetic field sources are compliant with the basic restrictions (BR) defined as the limits of the fields induced in the human body, i.e. the induced electric field/current density/specific absorption rate limits. This can be achieved by demonstrating compliance with the reference levels (RL) defined in air without the human body, i.e. the incident electric/magnetic field limits. Local sources, such as WPT transmitters, generate non-uniform fields that can locally exceed the RL while the induced fields are still well below the BR. In these cases, robust compliance with BR can be demonstrated, generally requiring a large number of simulations. In this study, we proposed an efficient evaluation using a homogeneous phantom and applying a coverage factor to account for the local field enhancements caused by the dielectric contrasts of the highly inhomogeneous human tissues. Approach. The generally applicable coverage factors were derived from a statistical analysis of the field enhancements observed on four magnetic near-field sources placed at different separation distances (2–80 mm) and locations on the back of 12 anatomical models. The field enhancements were characterized by the ratios between the peak induced fields in the anatomical models and those in the homogeneous half-space phantom (ϵ

r
= 55, σ = 0.75 S m−1, ρ = 1,000 kg m−3) at the same distance. Main results. The resulting 99th percentile coverage factors range from 1 and 9 depending on the dosimetric quantity. Significance. The use of these coverage factors reduces the compliance testing effort from hundreds of simulations to only one, and makes experimental testing feasible without the support of simulations. The study also demonstrates that running only a few use-case simulations with anatomical models may underestimate the exposure by more than 10 dB.
Characterisation of a split gradient coil design induced systemic imaging artefact on 0.35 T MR-linac systems
Authors: Marage Louis , Walker Paul-Michael , Boudet Julien , Fau Pierre , Debuire Pierre , Clausse Emmanuelle , Petitfils Aurélie , Aubignac Léone , Rapacchi Stanislas , Bessieres Igor 
Published: December 2022

Abstract

Objective. The aim of this work was to highlight and characterize a systemic ‘star-like’ artefact inherent to the low field 0.35 T MRIdian MR-linac system, a magnetic resonance guided radiotherapy device. This artefact is induced by the original split gradients coils design. This design causes a surjection of the intensity gradient in Z (or head-feet) direction. This artefact appears on every sequence with phase encoding in the head-feet direction. Approach. Basic gradient echo sequence and clinical mandatory bSSFP sequence were used. Three setups using manufacturer provided QA phantoms were designed: two including the linearity control grid used for the characterisation and a third including two homogeneity control spheres dedicated to the artefact management in a more clinical like situation. The presence of the artefact was checked in four different MRidian sites. The tested parameters based on the literature were: phase encoding orientation, slab selectivity, excitation bandwidth (BWRF), acceleration factor (R) and phase/slab oversampling (PO/SO). Main results. The position of this artefact is constant and reproducible over the tested MRIdian sites. The typical singularity saturated dot or star is visible even with the 3D slab-selection enabled. A management is proposed by decreasing the BWRF, the R in head-feet direction and increasing the PO/SO. The oversampling can be optimized using a formula to anticipate the location of artefact in the field of view. Significance. The star-like artefact has been well characterised. A manageable solution comes at the cost of acquisition time. Observed in clinical cases, the artefact may degrade the images used for the RT planning and repositioning during the treatment unless corrected.
A novel predictive analytics score reflecting accumulating disease burden—an investigation of the cumulative CoMET score
Authors: Monfredi Oliver , Andris Robert T , Lake Douglas E , Moorman J Randall 
Published: December 2022

Abstract
Objective. Predictive analytics tools variably take into account data from the electronic medical record, lab tests, nursing charted vital signs and continuous cardiorespiratory monitoring to deliver an instantaneous prediction of patient risk or instability. Few, if any, of these tools reflect the risk to a patient accumulated over the course of an entire hospital stay. Approach. We have expanded on our instantaneous CoMET predictive analytics score to generate the cumulative CoMET score (cCoMET), which sums all of the instantaneous CoMET scores throughout a hospital admission relative to a baseline expected risk unique to that patient. Main results. We have shown that higher cCoMET scores predict mortality, but not length of stay, and that higher baseline CoMET scores predict higher cCoMET scores at discharge/death. cCoMET scores were higher in males in our cohort, and added information to the final CoMET when it came to the prediction of death. Significance. We have shown that the inclusion of all repeated measures of risk estimation performed throughout a patients hospital stay adds information to instantaneous predictive analytics, and could improve the ability of clinicians to predict deterioration, and improve patient outcomes in so doing.
A novel deep domain adaptation method for automated detection of sleep apnea/hypopnea events
Authors: Du Zonglin , Wang Jiao , Ren Yingxin , Ren Yingtong 
Published: December 2022

Abstract

Objective. Sleep apnea–hypopnea syndrome (SAHS) is a common sleep-related respiratory disorder that is generally assessed for severity using polysomnography (PSG); however, the diversity of sampling devices and patients makes this not only costly but may also degrade the performance of the algorithms. Approach. This paper proposes a novel deep domain adaptation module which uses a long short-term memory–convolutional neural network embedded with the channel attention mechanism to achieve autonomous extraction of high-quality features. Meanwhile, a domain adaptation module was built to achieve domain-invariant feature extraction for reducing the differences in data distribution caused by different devices and other factors. In addition, during the training process, the algorithm used the last second label as the label of the PSG segment, so that second-by-second evaluation of respiratory events could be achieved. Main results. The algorithm applied the two datasets provided by PhysioNet as the source and target domains. The accuracy, sensitivity and specificity of the algorithm on the source domain were 86.46%, 86.11% and 93.17%, respectively, and on the target domain were 83.63%, 82.52%, 91.62%, respectively. The proposed algorithm showed strong generalization ability and the classification results were comparable to the current advanced methods. Besides, the apnea–hypopnea index values estimated by the proposed algorithm showed a high correlation with the manual scoring values on both domains. Significance. The proposed algorithm can effectively perform SAHS detection and evaluation with certain generalization.
Remobilized dust dynamics and inventory evolution in ITER-like start-up plasmas
Authors: Vignitchouk L , Paschalidis K , Ratynskaia S , Tolias P , Pitts R A 
Published: December 2022

Abstract
The dynamics of remobilized metallic dust are simulated with the MIGRAINe code in low-power ITER discharges meant to emulate reactor start-up environments. The particle size and speed distributions are varied along with plasma profiles to investigate the influence of initial and background parameters on high-Z impurity production by vaporization as well as long-term in-vessel dust inventory evolution over the course of consecutive discharges. Simulation output data regarding beryllium remobilization can be integrated into more global ITER models to guide the operation of dust diagnostics and facilitate the compliance with nuclear safety restrictions, while results on tungsten particles serve as a basis for first assessments of dust dynamics in DEMO.
Dipolar physics: a review of experiments with magnetic quantum gases
Authors: Chomaz Lauriane , Ferrier-Barbut Igor , Ferlaino Francesca , Laburthe-Tolra Bruno , Lev Benjamin L , Pfau Tilman 
Published: December 2022

Abstract
Since the achievement of quantum degeneracy in gases of chromium atoms in 2004, the experimental investigation of ultracold gases made of highly magnetic atoms has blossomed. The field has yielded the observation of many unprecedented phenomena, in particular those in which long-range and anisotropic dipole–dipole interactions (DDIs) play a crucial role. In this review, we aim to present the aspects of the magnetic quantum-gas platform that make it unique for exploring ultracold and quantum physics as well as to give a thorough overview of experimental achievements. Highly magnetic atoms distinguish themselves by the fact that their electronic ground-state configuration possesses a large electronic total angular momentum. This results in a large magnetic moment and a rich electronic transition spectrum. Such transitions are useful for cooling, trapping, and manipulating these atoms. The complex atomic structure and large dipolar moments of these atoms also lead to a dense spectrum of resonances in their two-body scattering behaviour. These resonances can be used to control the interatomic interactions and, in particular, the relative importance of contact over dipolar interactions. These features provide exquisite control knobs for exploring the few- and many-body physics of dipolar quantum gases. The study of dipolar effects in magnetic quantum gases has covered various few-body phenomena that are based on elastic and inelastic anisotropic scattering. Various many-body effects have also been demonstrated. These affect both the shape, stability, dynamics, and excitations of fully polarised repulsive Bose or Fermi gases. Beyond the mean-field instability, strong dipolar interactions competing with slightly weaker contact interactions between magnetic bosons yield new quantum-stabilised states, among which are self-bound droplets, droplet assemblies, and supersolids. Dipolar interactions also deeply affect the physics of atomic gases with an internal degree of freedom as these interactions intrinsically couple spin and atomic motion. Finally, long-range dipolar interactions can stabilise strongly correlated excited states of 1D gases and also impact the physics of lattice-confined systems, both at the spin-polarised level (Hubbard models with off-site interactions) and at the spinful level (XYZ models). In the present manuscript, we aim to provide an extensive overview of the various related experimental achievements up to the present.
Crystalline and optoelectronic properties of Ge1−x
Sn
x
/high-Si-content-Si
y
Ge1−x−y
Sn
x
double-quantum wells grown with low-temperature molecular beam epitaxy
Authors: Zhang Shiyu , Shibayama Shigehisa , Nakatsuka Osamu 
Published: December 2022

Abstract
In this study, we investigated the impact of the growth temperatures of molecular beam epitaxy method for the Si
y
Ge1−x−y
Sn
x
barrier with a Si content over 20% of Ge1−x
Sn
x
/Si
y
Ge1−x−y
Sn
x
single-quantum well (QW) on their crystalline and photoluminescence (PL) properties. As a result, we found that lowering T
SiGeSn down to 100 °C achieves the superior crystallinity and the higher PL efficiency at room temperature. It was owing to the suppression of the Sn segregation according to the surface morphology observation. Based on this finding, we realized the epitaxial growth of Ge1−x
Sn
x
/Si
y
Ge1−x−y
Sn
x
double-QWs at 100 °C. We verified the superior crystallinity with the abrupt interface by x-ray diffraction and scanning transmission electron microscopy. In this study, we discussed the optical transition mechanism of the single- and double-QWs based on the band alignment simulation. Finally, we found that the double-QW grown at 100 °C can sustain its crystalline structure against annealing at the N2 atmosphere up to 350 °C, and the PL performance can be also improved by the thermal treatment at around 350 °C.
Adaptive disturbance observer-based improved super-twisting sliding mode control for electromagnetic direct-drive pump
Authors: Lu Yingtao , Tan Cao , Ge Wenqing , Zhao Yanjun , Wang Geng 
Published: December 2022

Abstract
In this study, to enhance the frequency-flow characteristics of the novel electromagnetic direct-drive pump (EDDP). An adaptive disturbance observer-based improved super-twisting sliding mode control (ISTSMC-ADOB) is proposed to address the problem in which the response quality is deteriorated by factors such as parameter mismatch and disturbance. An adaptive disturbance observer (ADOB) is designed to achieve adaptive compensation, avoid the use of high-gain feedback, and extend the applicability of the conventional disturbance observer. An improved super-twisting sliding mode control (ISTSMC) based on the fast terminal sliding mode algorithm is designed to ensure faster convergence of the error in finite time. By combining the ADOB with the ISTSMC, the conservative parameter selection of the sliding mode control (SMC) is avoided, and the accuracy and robustness are further strengthened. The stability is analyzed based on Lyapunov. The results show that the proposed method effectively improves the steady-state accuracy, response speed, and robustness in trajectory tracking of the electromagnetic linear actuator for the EDDP. This further enhances the frequency-flow characteristics of the system.
A novel structural–functional integration piezoelectric thruster for miniature unmanned underwater vehicles
Authors: Liu Rui , Zhao Heng , Wang Liang , Jin Jiamei , Lai Dongyang , Chen Yuhang 
Published: December 2022

Abstract
Unmanned underwater vehicles (UUVs) play a vital role in marine exploration, and can achieve an extension of human hands and eyes to help researchers reach inaccessible and complex underwater spaces. However, the developed UUVs are driven by electromagnetic motors that also make it difficult to miniaturize due to the existence of the transmission system. Additionally, electromagnetic motors need to be protected to against water intrusion, especially in the deep sea. Therefore, in order to solve the above-mentioned problems, a novel structure-functional integration piezoelectric thruster for miniature UUVs is proposed in this study. Based on the converse piezoelectric effect and the direct friction drive principle, rudders and propellers can be alternately driven by a piezoelectric actuator, constructing the thrust unit and the steering unit of the piezoelectric thruster, respectively. Therefore, this makes the structure and function of the piezoelectric thruster integrated. Finite element simulations are first conducted to determine the geometrical sizes of the proposed actuator. The efficiency of the designed piezoelectric actuator is then confirmed using an underwater vibration measurement. Finally, experimental evaluations of the output performance of the piezoelectric thruster are performed. In the propulsion mode, the maximum rotation speed and thrust of the positive and negative propeller of the prototype with an excitation voltage of 600 Vpp were 404 rpm/0.10 N and 413 rpm/0.11 N, respectively. In the cooperative working mode, 20.00 kHz was used as the driving frequency, and the yaw and pitch rudders had the maximum average angle velocities of 92 deg s−1 and 90 deg s−1 for an excitation voltage of 600 Vpp, respectively. The maximum rotation speed and thrust of the positive and negative propellers of the prototype with an excitation voltage of 600 Vpp were 133 rpm/0.01 N and 132 rpm/0.01 N, respectively. According to experimental findings, the prototype piezoelectric thruster exhibits excellent mechanical properties.
Dimension dependent properties of subdiffusions in damping force fields from an inference perspective
Authors: He Yue , Kawai Reiichiro 
Published: December 2022

Abstract
We investigate the fractional Fokker-Planck equation subject to a damping force with an emphasis on its dimension dependent properties. We reveal a variety of surprising properties of its solution through the lens of the probability density function of the corresponding stochastic process with nonlinear mean square displacements, such as existence, singularity, regularity, modality, stationarity and second-order structure, which are largely dependent on the dimension and the random clock. Taking into account that the trajectory information is most often collected from multidimensional systems, the discovered facts have the potential to play important roles as key foundations and alerts for inference, model identification and prediction, when departing from the well-understood univariate framework.
Characterizations of -flat curvature tensor on spacetimes and

f(r,T)

-gravity
Authors: De Uday Chand , Hazra Dipankar 
Published: December 2022

Abstract
The prime goal of this article is to characterize spacetimes endowed with



-flat curvature tensor. It is demonstrated that a 4-dimensional



-flat perfect fluid spacetime is either a de-Sitter spacetime or locally isometric to Minkowski spacetime under certain energy condition. Moreover, it is established that a Ricci simple



-flat spacetime becomes a Robertson-Walker spacetime. In addition, we shown that a Ricci simple spacetime with harmonic



-curvature tensor is a generalized Robertson-Walker spacetime. Also, we explain several conclusions based on



-flat generalized Robertson-Walker spacetimes. Finally, we investigate



-flat spacetimes that satisfy the

f

r
,


-gravity and

f

r
,



m

-gravity.