bluuebunny/crossref_metadata_2025 huggingface dataset:
AQP4-IgG NMOSD, MOGAD, and double-seronegative NMOSD: is it possible to depict the antibody subtype using magnetic resonance imaging?
Authors: Fragoso Diego Cardoso , Salles Luana Michelli Oliveira de Paula , Pereira Samira Luisa Apóstolos , Callegaro Dagoberto , Sato Douglas Kazutoshi , Rimkus Carolina de Medeiros
Published: June 2023

Background There is clinical and radiological overlap among demyelinating diseases. However, their pathophysiological mechanisms are different and carry distinct prognoses and treatment demands.

Objective To investigate magnetic resonance imaging (MRI) features of patients with myelin-oligodendrocyte glycoprotein associated disease (MOGAD), antibody against aquaporin-4(AQP-4)-immunoglobulin G-positive neuromyelitis optica spectrum disorder (AQP4-IgG NMOSD), and double-seronegative patients.

Methods A cross-sectional retrospective study was performed to analyze the topography and morphology of central nervous system (CNS) lesions. Two neuroradiologists consensually analyzed the brain, orbit, and spinal cord images.

Results In total, 68 patients were enrolled in the study (25 with AQP4-IgG-positive NMOSD, 28 with MOGAD, and 15 double-seronegative patients). There were differences in clinical presentation among the groups. The MOGAD group had less brain involvement (39.2%) than the NMOSD group (p = 0.002), mostly in the subcortical/juxtacortical, the midbrain, the middle cerebellar peduncle, and the cerebellum. Double-seronegative patients had more brain involvement (80%) with larger and tumefactive lesion morphology. In addition, double-seronegative patients showed the longest optic neuritis (p = 0.006), which was more prevalent in the intracranial optic nerve compartment. AQP4-IgG-positive NMOSD optic neuritis had a predominant optic-chiasm location, and brain lesions mainly affected hypothalamic regions and the postrema area (MOGAD versus AQP4-IgG-positive NMOSD, p= 0 .013). Furthermore, this group had more spinal cord lesions (78.3%), and bright spotty lesions were a paramount finding to differentiate it from MOGAD (p = 0.003).

Conclusion The pooled analysis of lesion topography, morphology, and signal intensity provides critical information to help clinicians form a timely differential diagnosis.
Magnetic field evolution and reconnection in low resistivity plasmas
Authors: Boozer Allen H.
Published: June 2023

The mathematics and physics of each of the three aspects of magnetic field evolution—topology, energy, and helicity—are remarkably simple and clear. When the resistivity η is small compared to an imposed evolution, a/v, timescale, which means Rm≡μ0va/η≫1, magnetic field-line chaos dominates the evolution of field-line topology in three-dimensional systems. Chaos has no direct role in the dissipation of energy. A large current density, jη≡vB/η, is required for energy dissipation to be on a comparable timescale to the topological evolution. Nevertheless, chaos plus Alfvén wave damping explain why both timescales tend to be approximately an order of magnitude longer than the evolution timescale a/v. Magnetic helicity is injected onto tubes of field lines when boundary flows have vorticity. Chaos can spread but not destroy magnetic helicity. Resistivity has a negligible effect on helicity accumulation when Rm≫1. Helicity accumulates within a tube of field lines until the tube erupts and moves far from its original location.
The resolutions of drive-level capacitance profiling technique
Authors: Zhang Xin , Ma Yang , Zhang Zihang , Zhang Xiaobo , Yan Hui , Chen Xiaoqing , Zheng Zilong , Zhang Yongzhe
Published: June 2023

Recently, the drive level capacitance profiling (DLCP) technique has been proven to be effective in resolving the spatial and energetic distributions of defects through feasible measurements. However, the discussion on its ranges and resolutions is still missing, which is urgent in evaluating the validity of the calculated defect profiles. In this work, we propose a method to analyze the ranges and resolutions of DLCP. Assuming that the test instrument has more influence on the experimental results than the experimental environment, this method can be used to evaluate the resolution of DLCP for different test instruments. Through revisiting the equations involved in DLCP, we learned that the sources of the limits and resolutions are (1) the instrument system error and inherent resolution and (2) the device impedance. Consequently, from the study of device impedance and the measuring instrument system error, the resolutions of DLCP could be calculated according to the error propagation theory. We provide the spatial distribution of the minimum selection range of AC signal δV used by DLCP and the spatial resolution of DLCP technology. This method can be used to evaluate the resolution of DLCP for different test instruments.
Engineering inorganic interfaces using molecular nanolayers
Authors: Ramanath Ganpati , Rowe Collin , Sharma Geetu , Venkataramani Venkat , Alauzun Johan G. , Sundararaman Ravishankar , Keblinski Pawel , Sangiovanni Davide G. , Eklund Per , Pedersen Henrik
Published: June 2023

Advances in interface science over the last 20 years have demonstrated the use of molecular nanolayers (MNLs) at inorganic interfaces to access emergent phenomena and enhance a variety of interfacial properties. Here, we capture important aspects of how a MNL can induce multifold enhancements and tune multiple interfacial properties, including chemical stability, fracture energy, thermal and electrical transport, and electronic structure. Key challenges that need to be addressed for the maturation of this emerging field are described and discussed. MNL-induced interfacial engineering has opened up attractive opportunities for designing organic–inorganic hybrid nanomaterials with high interface fractions, where properties are determined predominantly by MNL-induced interfacial effects for applications.
Hilbert expansion based fluid models for kinetic equations describing neutral particles in the plasma edge of a fusion device
Authors: Maes V. , Dekeyser W. , Koellermeier J. , Baelmans M. , Samaey G.
Published: June 2023

Neutral particles in the plasma edge of fusion devices based on magnetic confinement are described by a transient kinetic equation incorporating ionization, recombination, and charge-exchange collisions. In charge-exchange dominated regimes, the neutral particle velocity distribution approaches the drifting Maxwellian defined by the mean velocity and temperature of the plasma. This enables model order reduction from the kinetic equation to approximate fluid models. We derive transient fluid models consistent with the kinetic equation by exploring a splitting based approach. We split the kinetic equation in sources and sinks on the one hand, and transport combined with charge-exchange on the other hand. Combining transport with charge-exchange collisions allows for deriving Hilbert expansion based fluid models. The retrieved fluid models depend on the assumed importance (scaling) of the different terms in the split equation describing transport and charge-exchange. We explore two scalings: the hydrodynamic scaling and the diffusive scaling. The diffusive scaling fluid model closely resembles phenomenological fluid models for describing neutral particles in the plasma edge that have been derived in the past. Therefore, the Hilbert expansion based fluid models can serve as a theoretical basis for such phenomenological fluid models and elucidate some of their properties. The performance of the fluid models with respect to a discrete velocity model and a Monte Carlo reference solver is assessed in numerical experiments. The code used to perform the numerical experiments is openly available.
Squeezing electronic noise with two tones
Authors: Paradis C. , Février P. , Pinsolle E. , Reulet B.
Published: June 2023

We have calculated and measured the effect of two ac excitations on the quantum shot noise of a tunnel junction. Using a phase-sensitive detection, we demonstrate that the junction generates squeezed microwave, in agreement with theory. While being weak, this squeezing should be extremely broadband.
Optical rectification Hall effect in a one-dimensional grating
Authors: Plumitallo Joseph , Moroshkin Peter , Ochiai Tetsuyuki , Osgood Richard M. , Xu Jimmy
Published: June 2023

We observe a transverse optical rectification current enhanced by surface plasmon polaritons in a one-dimensional gold thin film with a grating whose unit cell is asymmetric. In the linear regime, momentum transfer from incident laser light in one plane of incidence cannot yield an electrical current in the transverse direction. We show that a nonlinear system can cross-couple coordinates and lead to a transverse photocurrent despite no linear momentum transfer in the transverse direction. Nonlinear effects can be described by higher order terms in the polarization density expansion, which relates the polarization to the electric fields in the system, via linear and higher-order susceptibility tensor coefficients. We modify this expression with a phenomenological term to explain the counterintuitive observations.
A single-layer efficient polarization-insensitive electromagnetic rectifying metasurface for wireless power transfer
Authors: Wang Huai-Yu , Cheng Fei , Gu Chao
Published: June 2023

In this paper, an efficient electromagnetic rectifying metasurface (ERM) is proposed for wireless power transfer. The unit cell for the proposed ERM is composed of a cross-shaped energy capture structure that can absorb the electromagnetic power from the free space. The capture efficiency of the centrally symmetric structure exhibits insensitivity to the polarization of the incident wave. By directly connecting the Schottky diode to the ERM unit cell, the received electromagnetic power can be converted to DC power. The merit of the proposed ERM design is that no extra matching circuit is required, which can reduce the size, complexity, and insertion loss. To demonstrate the concept, a prototype of a 4 × 4-element ERM was fabricated and measured. The experimental results show that the proposed ERM array can produce up to 166 mW output DC power with an efficiency of 71.1% at an incident power density of 1050 μW/cm2. The polarization stability of the ERM is also verified by measurement with less than 10% efficiency reduction for different polarizations of the incident wave.
Low-frequency noise in hBN/MoS2/hBN transistor at cryogenic temperatures toward low-noise cryo-CMOS device applications
Authors: Nakaharai S. , Arakawa T. , Zulkefli A. , Iwasaki T. , Watanabe K. , Taniguchi T. , Wakayama Y.
Published: June 2023

As an application of cryo-CMOS technology for use in future quantum computing, we have explored low-frequency noise reduction in a two-dimensional (2D) system consisting of a molybdenum disulfide (MoS2) channel sandwiched by hexagonal boron nitride (hBN) layers. Due to the passivation effect of hBN layers, low-frequency noise in hBN/MoS2/hBN channel devices exhibited substantial reduction compared to the case of MoS2 channel directly on a silicon dioxide substrate and also silicon devices, suggesting that the clean interface of substrate and gate dielectric layers, as well as the protected surface of the MoS2 channel by hBN passivation from the damage by the fabrication process, contribute to the strong reduction in low-frequency noise. The results indicated that 2D materials are suitable for cryo-CMOS technology in terms of low-frequency noise since they will bring about mitigation of one of the most serious causes of quantum phase decoherence of qubits in future large-scale integrated quantum computers.
Molecular simulations of sliding on SDS surfactant films
Authors: Hörmann Johannes L. , Pastewka Lars
Published: June 2023

We use molecular dynamics simulations to study the frictional response of monolayers of the anionic surfactant sodium dodecyl sulfate and hemicylindrical aggregates physisorbed on gold. Our simulations of a sliding spherical asperity reveal the following two friction regimes: at low loads, the films show Amonton's friction with a friction force that rises linearly with normal load, and at high loads, the friction force is independent of the load as long as no direct solid–solid contact occurs. The transition between these two regimes happens when a single molecular layer is confined in the gap between the sliding bodies. The friction force at high loads on a monolayer rises monotonically with film density and drops slightly with the transition to hemicylindrical aggregates. This monotonous increase of friction force is compatible with a traditional plowing model of sliding friction. At low loads, the friction coefficient reaches a minimum at the intermediate surface concentrations. We attribute this behavior to a competition between adhesive forces, repulsion of the compressed film, and the onset of plowing.
Monitoring the Zn ion storage of Prussian blue analog via in situ spectral imaging strategy
Authors: Chen Naheng , Qiu Meijia , Zhao Chuanxi , Yan Genghua , Mai Wenjie , Sun Peng
Published: June 2023

Aqueous zinc-ion batteries (ZIBs) are rapidly developing, and powerful in situ monitoring methods can play a key role in their evolution, particularly for gaining a deeper understanding of the ion storage process in cathodes. To enhance the capabilities of in situ monitoring methods in the energy storage field, we apply an in situ optical recording technique combined with a multispectral imaging (MSI) reconstruction algorithm to study the charge storage process of ZIBs based on Prussian blue analog cathodes. The method can reconstruct time-domain spectra (TDS) based on optical reflectance at multiple wavelengths during online charging/discharging periods. Although the optical variation of the cathode is small, the reconstructed reflectance and real-time state of charge show excellent linearity with correlation coefficients all higher than 98%. Delicate peak shifts in TDS corresponding to phase variations in the cathodes can also be detected. Above all indicates great potential of the MSI strategy for accelerating the evolution of ZIBs and other batteries in the future.
Influence of the beta-effect on dynamics of frontal temperature jets
Authors: Goncharov V. P.
Published: June 2023

The theory of temperature jets gets extended to account for the influence of the beta effect on their dynamics. Including this effect noticeably changes symmetry properties and laws of conservation inherent to models without the beta effect. Specifically nontrivial, the dynamics of jets become near the equator, where the model admits multi-valued solutions that look like jets crossing the equator. For example, the so-called loop solitons moving along the equator with velocities inversely proportional to the cube of their amplitude turn out among them. Estimates based on simple qualitative considerations show that, owing to the beta effect, the temperature jets can form a specific equatorial turbulence, in which they play the role of structural elements. Notably, the spectral slope of the energy density at large wave numbers in such turbulence becomes equal to unity.
Study of polymerization of high-pressure nitrogen by ab initio molecular dynamics
Authors: Melicherová Dominika , Martoňák Roman
Published: June 2023

We study properties of nitrogen at high pressure and temperature (100–120 GPa, 2000–3000 K) where molecular and polymeric phases compete both in solid and liquid phase. We employ ab initio MD simulations with the SCAN functional and study the pressure-induced polymerization in liquid nitrogen for system sizes up to 288 atoms in order to reduce finite-size effects. The transition is studied upon both compression and decompression, and at 3000 K, it is found to take place between 110 and 115 GPa, coming close to experimental data. We also simulate the molecular crystalline phase close to the melting line and analyze its structure. We show that the molecular crystal in this regime is highly disordered, in particular, due to pronounced orientational and also translational disorder of the molecules. Its short-range order and vibrational density of states are very close to those of the molecular liquid revealing that the system likely represents a plastic crystal with high entropy.
Simulation on correlation of pulse ignition sensitivity for hot bridge wire EED
Authors: Lyu Xuxu , Wei Guanghui , Song Mingchang , Sun Jiangning , Zhao Hongze , Lu Xinfu
Published: June 2023

To solve the problem of testing the sensitivity under electromagnetic pulse radiation for a hot bridge wire electro-explosive device (EED), this paper simulated and analyzed the correlation between the critical ignition current under steady and pulse excitation. The simulation results showed that, under single pulse excitation, the critical ignition current of the EED decreases with the increase in the pulse width, and the variation law can be divided into three pieces: adiabatic, transition, and constant; while under pulse train excitation, due to the thermal cumulative effect, the critical ignition current is related to both material properties and excitation parameters. By analyzing the simulation results and considering the thermal ignition theory, the mathematical model of the critical ignition current under pulse excitation was established, and the mathematical model showed that under pulse train excitation, the critical ignition current is relevant not only to the single pulse excitation critical ignition current, pulse period, and duty cycle, but also to the ratio of single pulse and steady excitation critical ignition current and the thermal time constant. It was verified that the errors between the theoretical values obtained from the mathematical model and the results obtained from the simulation were within 2.5%.
Spin-selectivity effect of G-quadruplex DNA molecules
Authors: Deng Lei , Bhat Irfan Hussain , Guo Ai-Min
Published: June 2023

Chirality-induced spin selectivity has been attracting extensive interest in recent years and is demonstrated in a variety of chiral molecules, all of which arise from inherent molecular chirality. Here, we first propose a theoretical model to study the spin-dependent electron transport along guanine-quadruplex (G4) DNA molecules, connected to two nonmagnetic electrodes, by considering the molecule–electrode contact and weak spin–orbit coupling. Our results indicate that the G4-DNA molecular junctions exhibit pronounced spin-selectivity effect, and the asymmetric contact-induced external chirality, instead of the inherent molecular chirality, dominates their spin filtration efficiency. Furthermore, the spin-selectivity effect is robust against the disorder and hold in a wide range of model parameters. These results could be checked by charge transport measurements and provide an alternative way to improve the spin-selectivity effect of chiral nanodevices.
What are health professionals’ perceptions of conducting routine growth assessments and lifestyle interventions? A qualitative study involving allied health professionals, nurses and doctors in rural and regional New South Wales
Authors: Schwartzkoff Emma , Burrows Tracy , Bailey Andrew , Sneddon Eloise , Duncanson Kerith
Published: June 2023

Background Allied health professionals, nurses and doctors within the New South Wales (NSW) public health system provide trusted health information to a large proportion of families across the state. This means they are well positioned to opportunistically assess and discuss child weight status with families. Prior to 2016, weight status was not routinely addressed in most NSW public health settings, however recent policy changes promote quarterly growth assessments for all children aged under 16 years who attend these facilities. The Ministry of Health recommend health professionals use the 5 As framework, a consultation approach to encourage behaviour change, to identify and manage children with overweight or obesity. This study aimed to explore allied health professionals’, nurses’ and doctors’ perceptions of conducting routine growth assessments and providing lifestyle support to families in a local health district in rural and regional NSW, Australia. Methods This descriptive, qualitative study involved online focus groups and semi-structured interviews with health professionals. Audio recordings were transcribed and coded for thematic analysis, with rounds of data consolidation between research team members. Results Allied health professionals, nurses and doctors who work in a variety of settings within a local health district of NSW participated in one of four focus groups (n = 18 participants) or semi-structured interviews (n = 4). The predominant themes related to: (1) health professionals’ professional identity and their perceived scope of practice; (2) interpersonal qualities of health professionals; (3) the service delivery ecosystem in which health professionals worked. Diversity in attitudes and beliefs about routine growth assessments were not necessarily specific to discipline or setting. Conclusions Allied health professionals, nurses and doctors recognise the complexities involved in conducting routine growth assessments and providing lifestyle support to families. The 5 As framework used in NSW public health facilities to encourage behaviour change may not allow clinicians to address these complexities in a patient centred way. The findings of this research will be used to inform future strategies aimed at embedding preventive health discussions into routine clinical practice, and to support health professionals to identify and manage children with overweight or obesity.
Bone health, body composition and physical fitness dose–response effects of 16 weeks of recreational team handball for inactive middle‐to‐older‐aged males – A randomised controlled trial
Authors: Carneiro Ivone , Krustrup Peter , Castagna Carlo , Pereira Rita , Jørgensen Niklas Rye , Coelho Eduardo , Póvoas Susana
Published: June 2023

In this study we aimed at analysing the effects of different weekly exercise volumes (1, 2 or 3 times 60‐min) on bone health, body composition and physical fitness of inactive middle‐to‐older‐aged males, after 16 weeks of recreational team handball (RTH). Fifty‐four men (68 ± 4 years, stature 169 ± 6 cm; body mass 78.4 ± 10.7 kg; fat mass 27.1 ± 5.3%; BMI 27.4 ± 2.9 kg/m2; VO2peak 27.3 ± 4.8 mL/min/kg) were randomised into three intervention groups (TH1, n = 13; TH2, n = 15; or TH3, n = 12, performing 1, 2 and 3 weekly 60‐min training sessions, respectively), and a control group (CG, n = 14). The training sessions consisted mainly of RTH matches played as small‐sided and formal game formats (4v4, 5v5, 6v6 or 7v7) with adapted rules. Matches’ mean and peak heart rate (HR) ranged from 78–80% and 86–89%HRmax, respectively, and distance covered from 4676 to 5202 m. A time x group interaction was observed for procollagen type‐1 amino‐terminal propeptide (P1NP), osteocalcin (OC), carboxy‐terminal type‐1 collagen crosslinks (CTX), sclerostin, upper and lower body dynamic strength, right arm fat mass, left and right arm, right leg and android total mass (TM; p ≤ 0.047) with the greatest effects being shown for TH2 and TH3 groups. Post‐intervention group differences were observed in CTX, left arm and right leg TM (TH3 > TH1), P1NP (TH2 > CG), OC, right arm TM (TH3 > CG), upper (CG < TH1, TH2 and TH3) and lower body dynamic strength (CG < TH1 and TH3) (p ≤ 0.047). RTH was effective in enhancing bone health, body composition and physical fitness in middle‐to‐older‐aged males, especially for the intervention groups that performed 2–3 weekly training sessions.

ClinicalTrials.gov ID: NCT05295511.

Trial registration: ClinicalTrials.gov identifier: NCT05295511.

Highlights

After 16 weeks of recreational team handball small‐sided and formal matches, inactive middle‐to‐older‐aged males improved bone health, body composition and physical fitness, by performing 1, 2 or 3 60‐min weekly sessions, however, greater improvements were shown in the groups that performed 2 or 3 weekly training sessions.

Training intensity was similar across the intervention groups that performed recreational team handball for 1, 2 or 3 60‐min weekly sessions, which means that training volume is most likely to be the reason for the different health effects shown.

The very high fun levels reported by all intervention groups shows that recreational team handball is a social and fun exercise modality for middle‐to‐older‐aged males, with potential to intrinsically motivate the participants and assure long‐term adherence to exercise.
Mechanical control of the mammalian circadian clock via YAP/TAZ and TEAD
Authors: Abenza Juan F. , Rossetti Leone , Mouelhi Malèke , Burgués Javier , Andreu Ion , Kennedy Keith , Roca-Cusachs Pere , Marco Santiago , García-Ojalvo Jordi , Trepat Xavier
Published: June 2023

Autonomous circadian clocks exist in nearly every mammalian cell type. These cellular clocks are subjected to a multilayered regulation sensitive to the mechanochemical cell microenvironment. Whereas the biochemical signaling that controls the cellular circadian clock is increasingly well understood, mechanisms underlying regulation by mechanical cues are largely unknown. Here we show that the fibroblast circadian clock is mechanically regulated through YAP/TAZ nuclear levels. We use high-throughput analysis of single-cell circadian rhythms and apply controlled mechanical, biochemical, and genetic perturbations to study the expression of the clock gene Rev-erbα. We observe that Rev-erbα circadian oscillations are disrupted with YAP/TAZ nuclear translocation. By targeted mutations and overexpression of YAP/TAZ, we show that this mechanobiological regulation, which also impacts core components of the clock such as Bmal1 and Cry1, depends on the binding of YAP/TAZ to the transcriptional effector TEAD. This mechanism could explain the impairment of circadian rhythms observed when YAP/TAZ activity is upregulated, as in cancer and aging.
D-type K+ current rules the function of electrically coupled neurons in a species-specific fashion
Authors: Dapino Antonella , Davoine Federico , Curti Sebastian
Published: June 2023

Electrical synapses supported by gap junctions are known to form networks of electrically coupled neurons in many regions of the mammalian brain, where they play relevant functional roles. Yet, how electrical coupling supports sophisticated network operations and the contribution of the intrinsic electrophysiological properties of neurons to these operations remain incompletely understood. Here, a comparative analysis of electrically coupled mesencephalic trigeminal (MesV) neurons uncovered remarkable difference in the operation of these networks in highly related species. While spiking of MesV neurons might support the recruitment of coupled cells in rats, this rarely occurs in mice. Using whole-cell recordings, we determined that the higher efficacy in postsynaptic recruitment in rat’s MesV neurons does not result from coupling strength of larger magnitude, but instead from the higher excitability of coupled neurons. Consistently, MesV neurons from rats present a lower rheobase, more hyperpolarized threshold, as well as a higher ability to generate repetitive discharges, in comparison to their counterparts from mice. This difference in neuronal excitability results from a significantly higher magnitude of the D-type K+ current (ID) in MesV neurons from mice, indicating that the magnitude of this current gates the recruitment of postsynaptic-coupled neurons. Since MesV neurons are primary afferents critically involved in the organization of orofacial behaviors, activation of a coupled partner could support lateral excitation, which by amplifying sensory inputs may significantly contribute to information processing and the organization of motor outputs.
Falling off a balcony: a student experiment
Authors: Cross Rod
Published: June 2023

Falling accidents are very common and are sometimes fatal. A fatal fall could be accidental, suicidal or homicide and needs to be investigated. A simple model of falls from a balcony is presented, together with simulated experimental results obtained using a straight rod falling over a horizontal rail. The experiments involve basic mechanics and would be suitable in a student laboratory or as a lecture demonstration.
A flexible and highly sensitive capacitive pressure sensor with fast response based on a hierarchically micro-structured PDMS dielectric layer
Authors: Li Jiamin , Zhang Jie , Qin Lei , Lv Luyu , Liu Tianxiang , Zhang Yanting , Dhakal Rajendra , Li Xiao , Liu Tian , Li Yuanyue , Yao Zhao
Published: June 2023

Flexible high-sensitivity pressure sensors have seen rapid growth in the last few years in applications like electronic skin, smart wearables and medical health monitoring. In this work, we develop a high-flexibility capacitive pressure sensor design based on a hierarchical, micro-pyramid-structured dielectric layer of polydimethanes. The goal of this design is to achieve low-hysteresis capacitive pressure sensors with increased sensitivity and reduced response time. To optimize the performance of the proposed pressure sensor, we designed and fabricated several different micro-pyramid structures on the silicon template using standard photolithography and anisotropic etching. As a result, the pressure sensor with a hierarchical micro-pyramid structure achieved through graphic transfer has the best performance, with a sensitivity of up to 2.64 kPa−1 (0–2 kPa), a response time of 45 ms, a low limit of detection of < 8 Pa, and high stability over at least 1200 loading cycles. As a result of these remarkable performance features, the pressure sensor proposed can be effectively utilized for the detection of physiological signals as well as mechanical pressure which can be widely used in the fields of motion sensing, health monitoring and intelligent robots.
Buried interfacial gate oxide for tri-gate negative-capacitance fin field-effect transistors: approach and investigation
Authors: Chauhan Vibhuti , Samajdar Dip Prakash
Published: June 2023

Negative-capacitance fin field-effect transistors (NC-FinFETs), due to their superior gate electrostatics and dominance over short channel effects (SCEs), have been a key technology among conventional devices. The improved device performance in terms of the various engineering practices has paved the way for the advancement of NC-FinFETs. In the following work, we have proposed a novel buried oxide strategy for the NC-FinFET architecture, in which we have altered the depth of the interfacial gate oxide (IGO) layer inside the channel and analyzed the performance characteristics using TCAD Sentaurus. First, we varied the IGO thickness that was buried inside the channel and performed a comparative analysis between the DC, mixed-mode, and SCE parameters for the various buried configurations of the proposed NC-FinFET in order to realize the optimized depth. We also present the tolerable degradation in the circuit characteristics that occurs with the varying buried IGO (BIGO) depth. It can be inferred from the presented interface trap discussion that the idea of BIGO thickness holds well for low-power electronics.
Knowledge features enhanced intelligent fault detection with progressive adaptive sparse attention learning for high-power diesel engine
Authors: Li He , Liu Fengchun , Kong Xiangxin , Zhang Jinjie , Jiang Zhinong , Mao Zhiwei
Published: June 2023

High-power diesel engines are core power equipment in some key fields, and fault diagnosis is of great significance for improving their long-term operational reliability and safety. The lack of sufficient fault samples, known as few-shot conditions, has resulted in the performance degradation of most current intelligent diagnostic methods under complex and variable working conditions. Moreover, the end-to-end deep learning diagnostic models based on implicit layer features do not have clear physical meanings, making it difficult for intelligent diagnostic models to be recognized by equipment managers in key fields. Mechanism-based fusion methods can effectively alleviate the above problems by incorporating fault-sensitive features with clear physical meanings. However, the lack of sufficient knowledge-related features that can characterize fault information is a challenge facing current mechanism fusion methods. In this work, we propose a progressive adaptive sparse attention mechanism-guided knowledge feature incremental mining method. Fault-sensitive segments are obtained based on attention-supervised learning with an improved activation function. Both knowledge-related features and hidden layer features from these segments are incorporated into the feature library. A differential constraint is designed between the distribution of knowledge features and hidden layer features, encouraging the model to focus on learning new knowledge-related features in the subsequent iteration process. Finally, a feature set containing a large amount of knowledge features is constructed to enhance fault diagnosis. Testing on a V12 diesel engine test bench under the conditions of rich and few-shot data sets, shows that the proposed method significantly enhances the fault recognition performance of diesel engines under complex variable working conditions and few-shot data set conditions.
Simultaneous photon counting and charge integrating for pulse pile-up correction in paralyzable photon counting detectors
Authors: Treb Kevin , Radtke Jeff , Culberson Wesley S , Li Ke
Published: June 2023

Objective. In photon counting detectors (PCDs), electric pulses induced by two or more x-ray photons can pile up and result in count losses when their temporal separation is less than the detector dead time. The correction of pulse pile-up-induced count loss is particularly difficult for paralyzable PCDs since a given value of recorded counts can correspond to two different values of true photon interactions. In contrast, charge (energy) integrating detectors work by integrating collected electric charge induced by x-rays over time and do not suffer from pile-up losses. This work introduces an inexpensive readout circuit element to the circuits of PCDs to simultaneously collect time-integrated charge to correct pile-up-induced count losses. Approach. Prototype electronics were constructed to collect time-integrated charges simultaneously with photon counts. A splitter was used to feed the electric signal in parallel to both a digital counter and a charge integrator. After recording PCD counts and integrating collected charge, a lookup table can be generated to map raw counts in the total- and high-energy bins and total charge to estimate pile-up-free true counts. Proof-of-concept imaging experiments were performed with a CdTe-based PCD array to test this method. Main results. The proposed electronics successfully recorded photon counts and time-integrated charge simultaneously, and whereas photon counts exhibited paralyzable pulse pile-up, time-integrated charge using the same electric signal as the counts measurement was linear with x-ray flux. With the proposed correction, paralyzable PCD counts became linear with input flux for both total- and high-energy bins. At high flux levels, uncorrected post-log measurements of PMMA objects severely overestimated radiological path lengths for both energy bins. After the proposed correction, the non-monotonic measurements again became linear with flux and accurately represented the true radiological path lengths. No impact on the spatial resolution was observed after the proposed correction in images of a line-pair test pattern. Significance. Time-integrated charge can be used to correct for pulse pile-up in paralyzable PCDs where analytical solutions may be difficult to use, and integrated charge can be collected simultaneously with counts using inexpensive electronics.
Physics-informed neural networks for solving nonlinear Bloch equations in atomic magnetometry
Authors: Lei Gaoyi , Ma Ning , Sun Bowen , Mao Kun , Chen Baodong , Zhai Yueyang
Published: June 2023

In this study, we address the challenge of analyzing spatial spin distribution based on the nonlinear Bloch equations in atomic magnetometry through the use of physics-informed neural networks (PINNs). Atomic magnetometry plays a crucial role in the field of biomagnetism, where it is used to detect weak magnetic fields produced by the human brain, heart, and other organs. The Bloch equations describe the spin polarization of atomic clusters in an external magnetic field, but their nonlinearity can make the analysis of the spin distribution in spatial domain difficult. By utilizing PINNs, we provide a numerical solution to the nonlinear Bloch equations, examining the effect of different pump light schemes and wall collisions. Additionally, we propose a easily executed system identification method for the Bloch equations through the use of PINNs in a data-driven discovery mode, expanding the design space of atomic magnetometry beyond traditional simulation methods.
Novel double channel reverse conducting GaN HEMT with an integrated MOS-channel diode
Authors: Xie 谢 Xintong 欣桐 , Zhang 张 Cheng 成 , Zhao 赵 Zhijia 智家 , Wei 魏 Jie 杰 , Luo 罗 Xiaorong 小蓉 , Zhang 张 Bo 波
Published: June 2023

A novel normally-off double channel reverse conducting (DCRC) HEMT with an integrated MOS-channel diode (MCD) is proposed and investigated by TCAD simulation. The proposed structure has two features: one is double heterojunctions to form dual 2DEG channels named the 1st path and the 2nd path for reverse conduction, and the other is the MCD forming by the trench source metal, source dielectric, and GaN. At the initial reverse conduction stage, the MCD acts as a switch to control the 1st path which would be turned on prior to the 2nd path. Because of the introduction of the 1st path, the DCRC-HEMT has an additional reverse conducting channel to help enhance the reverse conduction performance. Compared with the conventional HEMT (Conv. HEMT), the DCRC-HEMT can obtain a low reverse turn-on voltage (V
RT) and its V
RT is independent of the gate–source bias (V
GS) at the same time. The DCRC-HEMT achieves the V
RT of 0.62 V, which is 59.7% and 75.9% lower than that of the Conv. HEMT at V
GS = 0 V and −1 V, respectively. In addition, the forward conduction capability and blocking characteristics almost remain unchanged. In the end, the key fabrication flows of DCRC-HEMT are presented.
DRC-Net Method for Two-dimensional Spectral Classification
Authors: Zhang Ming-Ru , Gao Jun-Ping , Qiu Bo , Pu Yuan , Wang Xiao-Min , Li Rong , Fan Ya-Wen
Published: June 2023

Spectral classification plays a crucial role in the analysis of astronomical data. Currently, stellar spectral classification primarily relies on one-dimensional (1D) spectra and necessitates a sufficient signal-to-noise ratio (S/N). However, in cases where the S/N is low, obtaining valuable information becomes impractical. In this paper, we propose a novel model called DRC-Net (Double-branch celestial spectral classification network based on residual mechanisms) for stellar classification, which operates solely on two-dimensional (2D) spectra. The model consists of two branches that use 1D convolutions to reduce the dimensionality of the 2D spectral composed of both blue and red arms. In the following, the features extracted from both branches are fused, and the fused result undergoes further feature extraction before being fed into the classifier for final output generation. The data set is from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope, comprising 15,680 spectra of F, G, and K types. The preprocessing process includes normalization and the early stopping mechanism. The experimental results demonstrate that the proposed DRC-Net achieved remarkable classification precision of 93.0%, 83.5%, and 86.9% for F, G, and K types, respectively, surpassing the performance of 1D spectral classification methods. Furthermore, different S/N intervals are tested to judge the classification ability of DRC-Net. The results reveal that DRC-Net, as a 2D spectral classification model, can deliver superior classification outcomes for the spectra with low S/Ns. These experimental findings not only validate the efficiency of DRC-Net but also confirm the enhanced noise resistance ability exhibited by 2D spectra.
Investigation of helium exhaust dynamics at the ASDEX Upgrade tokamak with full-tungsten wall
Authors: Zito A. , Wischmeier M. , Kappatou A. , Kallenbach A. , Sciortino F. , Rohde V. , Schmid K. , Hinson E.T. , Schmitz O. , Cavedon M. , McDermott R.M. , Dux R. , Griener M. , Stroth U.
Published: June 2023

An efficient removal of He ash by active pumping in future fusion devices is necessary to avoid fuel dilution and not degrade the core confinement properties. Therefore, a deep understanding of the underlying physics mechanisms is mandatory. Helium exhaust has been experimentally investigated at the ASDEX Upgrade tokamak. This is an ideal test environment, thanks to the ITER-like divertor geometry, an extensive diagnostics coverage and the presence of plasma-facing components made of tungsten. The exhaust efficiency, characterized by the He compression in the divertor, was found to improve with increasing divertor neutral pressure but to degrade with detachment. A multi-reservoir particle balance model was developed to interpret the observed exhaust dynamics, accounting for plasma transport and wall retention. The limited performance of the pumping system and the efficient helium retention capability of the tungsten wall were identified to have the strongest impact on the exhaust dynamics.
A rule-based energy management strategy for hybrid powered eVTOL
Authors: Marzougui Taher , Saenz Eduard Solano , Bareille Michel
Published: June 2023

In recent years, as the levels of air pollution reach alarming degrees, new energy aerial vehicles like electric Vertical Take-Off and Landing (eVTOL) aircraft have become the development trend of the future aviation industry. This paper presents a rule-based energy management strategy (EMS) for an eVTOL. The Hybrid Power System (HPS) is composed of Proton Exchange Membrane Fuel Cells (PEMFC) as the main energy source and Lithium-ion batteries (Li-ion) as auxiliary one. The onboard sources deliver power to the DC bus through two DC-DC converters. The main objective is to optimally split the power demand between the different sources while respecting their limits and extending their lifetimes. The adopted control strategy is based on State Machine Control (SMC). It is described as a set of rules based on some predefined conditions and thresholds over the control variables. It is chosen due to its simplicity of implementation, its reliability, and a low computation time. The relevance of this strategy is evaluated and implemented on a set of simulations for an eVTOL mission corresponding to a search and rescue flight. Results on power distribution, fuel cell dynamics, and battery parameters are analysed. They confirm the effectiveness of the proposed strategy.
Application of Model-Based Systems Engineering for the Integration of Electric Engines in Electrified Aircraft
Authors: Kiran Abhishek , Zaghari Bahareh , Kipouros Timoleon , Reis Ricardo Jose Nunes Dos
Published: June 2023

The objective of green, carbon-neutral flights is propelling the innovation of newer propulsion systems. With this increased development of an interdisciplinary form of propulsion for aircraft, the integration burdens and efforts intensify. In literature, it is estimated that it takes 10-15 years to design and develop an aircraft. The expected date of entry for any hybrid electric aircraft is 2035-2040. Any innovation and effort to cut this time by any degree should be explored and analysed. One of the techniques that have the potential to help fast-track the research and development of interdisciplinary systems is Model-based System Engineering (MBSE). Various studies have shown the benefit of employing a model-based design strategy. The focus case study relates to the integration of the electric machine and the propeller, along with related sub-systems. For Hybrid Electric Propulsion (HEP), the electric machine and propeller need to be integrated and their interaction to be analysed. MBSE is proposed as a methodology that would help streamline the process of design and integration of the two systems. This study documents the exploration of connecting MBSE with current simulation and modelling of sub-systems in order to ensure the fulfilment of stakeholder needs and full system effectiveness. This paper establishes the research problem, and the approach to be pursued, and gives notice of first developments and expected follow-up work.
Development, optimization, and testing of a hybrid solar panel concept with energy harvesting enhancement
Authors: Pattath Saseendran A , Hartl C , Tian Y , Qin Y
Published: June 2023

Photovoltaics (PV) is one of the important technologies for electricity generation from renewable energies today and has an excellent environmental sustainability. It is a fast-growing market worldwide and also offers opportunities for aviation to intensify the use of renewable sources. Although the efficiency of PV systems has increased to a certain extent in recent years, a predominant part of solar radiation acting on a PV system is still lost to the environment through reflection and convection as well as heat radiation from the heated PV system. In addition, the efficiency of these systems decreases with increasing heating. Possible solutions for energy harvesting of this energy loss through thermoelectric (TE) have been investigated theoretically and in part experimentally in various cases but have not yet been transferred to larger PV systems. At the same time, cooling the PV system through thermogenerators (TEG) allows its efficiency to be increased. This contribution presents first results from investigations into the design and testing of hybrid PV/TEG systems, which aim to increase the efficiency and improve economic manufacturability of such systems. Among others, important design aspects of hybrid PV/TEG systems and integration of IoT elements (Internet of Things) are addressed and the development of an analytical model to optimise hybrid systems is presented.
Mechanical behaviour for aeronautical structures with embedded electric cables under low energy impact
Authors: Vogel T , Walrick J-C , Casari P
Published: June 2023

The work focuses on the mechanical strength of composite structures with embedded electrical functionalities submitted to low energy impact. This material is defined for aeronautical applications as multilayers of glass fibre composite with flat electrical cable layers embedded. The main question is about the damage involved by the low energy impact, and its influence on the electrical cables layer performances. The impact leads to failure with no external signs of damage and insulation degradation. The dynamic experimental campaigns are carried out on drop tower tests with hemispherical tool. localized damage mechanisms at conductor interfaces are observed and a finite element model is performed. A link between impact energies and loss of electrical performance of multifunctional samples is established.
Description of the structure-property-function (SPF) relations of CNT-doped adhesive composites for the development of functional blocks
Authors: Tzortzinis Georgios , Madia Evgenia , Filippatos Angelos
Published: June 2023

In novel CNT-enhanced composite materials there has been noted a significant gap between material development and their application in engineering fields. In this context, we apply a function-integration design approach, where we propose a targeted material development and standardization through the adaption of functional blocks. Utilizing the structure-property-function (SPF) relations on the case study of CNT-doped adhesives, we map the internal structure of the system to targeted functions through selected properties. We highlight the influence of volume fraction and aspect ratio of CNTs on the homogenized properties of the composite and their extension on the targeted functions. We conclude that there exists a link between structure, property and function in a form which can be characterized as a functional block. Such approach can provide way to a standardized material selection, succeeding in a more function-oriented design of materials.