bluuebunny/crossref_metadata_2025 huggingface dataset:
Enlarged Intracranial Translucency, as a Potential Marker for Diagnosis of Joubert Syndrome during First-Trimester Screening: A Case Report
Authors: Verma Heena , Patel B I. , Patel Nisha S. , Patel Saumil B.
Published: May 2023

Joubert syndrome (JS) is a rare autosomal recessive neurodevelopmental disorder that is usually diagnosed late in pregnancy or postnatally based on a pathognomonic midbrain–hindbrain malformation seen on magnetic resonance imaging brain, which consists of the hypoplasia of the cerebellar vermis, thickened superior cerebellar peduncles, and a deepened interpeduncular fossa described as molar tooth sign. The recurrence rate of JS in the same family is high (25%). In the era of first-trimester anomaly scan, early diagnosis of fetal anomaly is of utmost importance. First-trimester screening or first-trimester scan that is performed from 11 to 13 weeks, 6 days plays an important role in early diagnosis of posterior fossa abnormalities like Blake's pouch cyst, Vermian hypoplasia, Dandy-Walker malformation, and JS and related disorders based on increased intracranial translucency thickness. Our case also shows that early diagnosis of JS can be done by an enlarged intracranial translucency.
Liquid metals: A solid foundation for flexible electronics
Authors: Shapiro Maura
Published: May 2023

A promising range of applications for gallium-based metal and polymer composites
Employing thermal protein unfolding to search for new drugs
Authors: Thompson Avery
Published: May 2023

Thermal unfolding methods provide a fast and easy way to screen multiple compounds for protein interactions.
Anisotropic magnetoresistance and the field-induced anomalous valley inversion in half-Heusler TbPtBi
Authors: Chen Jie , Chen Peng , Guo Tengyu , Zheng Dongfeng , Li Hang , Yu Guoqiang , Lau Yong-Chang , Xi Xuekui , Wang Wenhong
Published: May 2023

We have performed detailed magnetic and anisotropic magnetoresistance (AMR) measurements on a magnetic-field-induced topological Weyl semimetal, TbPtBi, exhibiting a weak metamagnetic transition in the antiferromagnetic state. The magnetic torque and temperature-dependent AMR measurements indicate that the spin order dominates the symmetry of AMR curves at temperature below Neel temperature (TN) and low magnetic fields. Remarkably, the AMR with a twofold symmetry gradually dominates the curves as the magnetic fields increase. Moreover, sign change in the AMR effect is confirmed for both T < TN and T > TN at high magnetic fields, which may be related to the magnetic field-induced splitting of the topological band in TbPtBi.
Modeling of the driver transverse profile for laser wakefield electron acceleration at APOLLON research facility
Authors: Moulanier I. , Dickson L. T. , Ballage C. , Vasilovici O. , Gremaud A. , Dobosz Dufrénoy S. , Delerue N. , Bernardi L. , Mahjoub A. , Cauchois A. , Specka A. , Massimo F. , Maynard G. , Cros B.
Published: May 2023

The quality of electron bunches accelerated by laser wakefields is highly dependant on the temporal and spatial features of the laser driver. Analysis of experiments performed at APOLLON PW-class laser facility shows that spatial instabilities of the focal spot, such as shot-to-shot pointing fluctuations or asymmetry of the transverse fluence, lead to charge and energy degradation of the accelerated electron bunch. It is shown that PIC simulations can reproduce experimental results with a significantly higher accuracy when the measured laser asymmetries are included in the simulated laser's transverse profile, compared to simulations with ideal, symmetric laser profile. A method based on a modified Gerchberg–Saxton iterative algorithm is used to retrieve the laser electric field from fluence measurements in vacuum in the focal volume, and accurately reproduce experimental results using PIC simulations, leading to simulated electron spectra in close agreement with experimental results, for the accelerated charge, energy distribution, and pointing of the electron beam at the exit of the plasma.
Spectroscopy of helium-tagged molecular ions—Development of a novel experimental setup
Authors: Bergmeister Stefan , Ganner Lisa , Locher Johannes , Zappa Fabio , Scheier Paul , Gruber Elisabeth
Published: May 2023

In this contribution, we present an efficient and alternative method to the commonly used RF-multipole trap technique to produce He-tagged molecular ions at cryogenic temperatures, which are perfectly suitable for messenger spectroscopy. The seeding of dopant ions in multiply charged helium nanodroplets, in combination with a gentle extraction of the latter from the helium matrix, enables the efficient production of He-tagged ion species. With a quadrupole mass filter, a specific ion of interest is selected, merged with a laser beam, and the photoproducts are measured in a time-of-flight mass-spectrometer. The detection of the photofragment signal from a basically zero background is much more sensitive than the depletion of the same amount of signal from precursor ions, delivering high quality spectra at reduced data acquisition times. Proof-of-principle measurements of bare and He-tagged Ar-cluster ions, as well as of He-tagged C60 ions, are presented.
Enhanced water activation in gas–liquid two-phase flow using air plasma droplets
Authors: Xu Han , Xu Hancheng , Huang Yihong , Wei Zipeng , Zhang Hao , Shao Mingxu , Xie Kai
Published: May 2023

We report on our study of gas–liquid two-phase flow of air plasma and its associated dynamic behavior, droplet activity, and applications. The propagation of the air plasma jet within a Venturi configuration is significantly perturbed by the presence of water droplets due to the local modification of the electric field that results from polarization and charging of the droplets. This local modulation, in turn, decreases the discharge current pulses and the radiation intensity of optical emissions. With a change in inlet airflow dynamics from laminar to turbulent (5–10 L/min), the droplet diameter decreased exponentially under strong pressure from millimeter to several tens of micrometers, whereas the gas–droplet contact area increased substantially. The production of short-lived reactive aqueous species OH and O2− was enhanced at the gas–liquid interface of the biphasic plasma droplets, and the activities of different long-lived species (H2O2, NO3−, and O3) in the droplet were highly selective in droplet diameter and value of the Henry-law constants. This new plasma source architecture enables an in situ activation of water sprays by plasma jets at short time scales, providing a desirable and effective sterilization tool and wastewater treatment at a relatively low cost and ease of operation.
Atomistic investigations of Cr effect on the deformation mechanisms and mechanical properties of CrCoFeNi alloys
Authors: Yao Yi , Zhang Zhengyu , Cai Wenjun , Li Lin
Published: May 2023

The emerging class of multi-principal element alloy (MPEA) processes superior mechanical properties and has great potential for applications in extreme environments. In this work, the synergic effect of the Cr content and crystallographic orientation on the deformation behaviors of single-crystal CrCoFeNi MPEAs has been investigated by atomistic simulations. We have found distinct differences in dislocation activities, deformation microstructures, and mechanical behaviors in the model MPEAs, which depend on crystallographic orientations, Cr concentration, and the number of activated slip systems. When multiple slip systems are triggered along [100] and [111] orientations, Shockley partial activation and their interaction are predominant, leading to the formation of sessile dislocations and a dense dislocation network. When only two slip systems of Shockley partials are favored along the [110] direction, the influence of Cr concentration and planner defect energies emerges. At low Cr concentration, the double planar slip of Shockley partials results in deformation-induced nanotwins. At high Cr concentration, the partial dislocations of a single slip plane become dominant, attaining the highest volume fraction of deformation-induced phase transformation. The results provide a fundamental understanding of deformation mechanisms in MPEAs, elucidating the synergic effect of crystal orientation and composition on tunning the mechanical behaviors.
Monte Carlo simulation of ion kinetics in nitrogen and oxygen plasmas under non-uniform electric field conditions
Authors: Ponomarev A. A. , Aleksandrov N. L.
Published: May 2023

The kinetics of N4+ and O− ions was numerically studied in nitrogen and oxygen plasmas in a highly non-uniform electric field. Mean ion energy and reaction rate coefficients in a background gas at pressures from 1 to 10 Torr were calculated through a Monte Carlo simulation. The ion characteristics followed the local reduced electric field at high pressures, whereas nonhydrodynamic effects leading to a nonlocal dependence of the mean ion energy and rate coefficients on the field were obtained at low pressures. As a result, the rates of N4+ ion dissociation, electron detachment from O− ions, and charge exchange in collisions between O− and O2 lagged the local field value. The non-local effect on the ion rate coefficients was more profound when the field decreased in space. We suggested a simplified method of describing ion rates in spatially varying electric fields on the basis of the Monte Carlo simulation of these rates for uniform electric field conditions and mean ion energy calculations in non-uniform fields. This method is similar to the local-mean-energy approximation utilized for describing electron swarm parameters in varying electric fields. The results of the simplified method were compared with the results of the direct Monte Carlo simulation.
Spin polarization effects in trigonal mixed-valence complexes exhibiting double exchange supported by external spin-cores
Authors: Palii Andrew , Korchagin Denis , Kondrina Ksenya , Aldoshin Sergey , Zilberg Shmuel , Tsukerblat Boris
Published: May 2023

The theory of the magnetic coupling between the localized spins, mediated by the mobile excess electron, is generalized to the case of a trigonal, six-center, four-electron molecule with partial valence delocalization. The combination of the electron transfer occurring within the valence-delocalized subsystem and the interatomic exchange producing coupling of the spin of the mobile electron of valence-delocalized fragment with the three localized spins forming the valence-localized subsystem leads to the appearance of a special kind of double exchange (DE), termed the “external core double exchange” (ECDE), in order to distinguish such DE from the conventional “internal core double exchange” for which the mobile electron is coupled with the spin-cores on the same center via the intra-atomic exchange. The effect of the ECDE on the ground spin state of the considered trigonal molecule is compared with earlier reported effect produced by DE in the four-electron, mixed-valence (MV) trimer. A high diversity of the ground spin states is revealed, depending on the relative magnitudes and signs of the electron transfer and interatomic exchange parameters, with part of these states not appearing to be the ground states in a trigonal trimer exhibiting DE. We briefly discuss some examples of trigonal MV systems from the point of view of the possibility to have different combinations of signs of the transfer and exchange parameters and, accordingly, different ground spin states. The tentative role of the considered systems in molecular electronics and spintronics is also noticed.
On the interaction between liquid slug and vapor bubble in the chaotic operation of pulsating heat pipe
Authors: Kumar Alok , Singh Suneet
Published: May 2023

A pulsating heat pipe has shown promising results in heat transfer enhancement for several industrial applications. Despite having multiple advantages in the design and physics-based parameters, its applications are still limited due to the lack of understanding of the dynamics of the chaotic interaction of the liquid slug and vapor bubble. The randomly distributed liquid slug and vapor bubble start oscillating upon applying the heat at the evaporator section. A transition from the self-sustained oscillatory to chaotic operation in the pulsating heat pipe has been observed in various experimental studies. However, there are only a few works explaining the chaotic interaction of liquid slugs and vapor bubbles. We present the analysis of the oscillatory behavior of the position of the liquid slug in the pulsating heat pipe using a nonlinear mathematical model. The identification of various operating regions in the parameter space using the bifurcation analysis reveals the presence of a route to chaos by the period-doubling bifurcation. The fast Fourier transform of the temporal evolutions confirms the presence of the period doubling phenomena. Furthermore, the Lyapunov exponent and the correlation dimension are used to detect chaos and quantify the dimension of the chaotic attractor, respectively. Moreover, the Hurst exponent is used to determine the persistency of the oscillations, which indicates that the oscillations are weakly persistent in the chaotic regime. The transition to the chaotic regime is analyzed by period doubling, and a change in the frequency beyond period-doubling shows a gradual shift to the chaotic operation.
Boson-peak vibrational modes in glasses feature hybridized phononic and quasilocalized excitations
Authors: Lerner Edan , Bouchbinder Eran
Published: May 2023

A hallmark of structural glasses and other disordered solids is the emergence of excess low-frequency vibrations on top of the Debye spectrum DDebye(ω) of phonons (ω denotes the vibrational frequency), which exist in any solid whose Hamiltonian is translationally invariant. These excess vibrations—a signature of which is a THz peak in the reduced density of states D(ω)/DDebye(ω), known as the boson peak—have resisted a complete theoretical understanding for decades. Here, we provide direct numerical evidence that vibrations near the boson peak consist of hybridizations of phonons with many quasilocalized excitations; the latter have recently been shown to generically populate the low-frequency tail of the vibrational spectra of structural glasses quenched from a melt and of disordered crystals. Our results suggest that quasilocalized excitations exist up to and in the vicinity of the boson-peak frequency and, hence, constitute the fundamental building blocks of the excess vibrational modes in glasses.
Kinetic effects on geodesic acoustic modes and Stringer spin-up driven by a poloidally asymmetric particle source
Authors: Lee Young-Hoon , Jhang Hogun , Kim S. S. , Lee Jungpyo
Published: May 2023

The impact of the poloidally inhomogeneous particle source on the onset of Stringer spin-up (SSU) and geodesic acoustic mode (GAM) is investigated. Using a gyrofluid model with Hammet–Perkins closure, it was found that Landau damping stabilizes both waves and subsequently makes a threshold. To capture the full effects of Landau damping, a gyrokinetic model is adopted and results are compared with those from the gyrofluid model. Both models predicted the same value of the threshold for SSU, while for the case of GAM, the gyrofluid model overestimates the threshold value. Considering maximal throughput of the ITER pellet fueling system, the source intensity is calculated at a similar or slightly lower level compared to the source threshold for SSU.
Influence of coaxial fuel–air jets on mixing performance of extruded nozzle at supersonic combustion chamber: Numerical study
Authors: Shi Xiaoling , Song Dunlan , Tian Hui , Alizadeh As'ad , Ali Masood Ashraf , Shamsborhan Mahmoud
Published: May 2023

Increasing the mixing efficiency of the fuel jet along the combustion chamber is a crucial step for the advancement of the current high-velocity vehicles. In this article, comprehensive computational investigations have been performed to disclose the role of an annular air jet on the fuel mixing of the single extruded nozzle located inside the combustion chamber. This study has tried to offer hydrodynamic insight about the jet flow feature when released from the extruded nozzle in supersonic cross flow. Computational fluid dynamic is used for the visualization of fuel jet interactions with air stream. Effects of nozzle height on the mechanism of fuel jets are extensively analyzed in this investigation. Our results show that the injection of the annular jet would increase the strength of the circulations, and consequently, fuel mixing improves inside the combustion chamber. Our findings display that fuel mixing increases about 100% by the injection of the annular air jet in the combustion chamber.
Microscopic single-pixel polarimetry for biological tissue
Authors: Wang Yazhen , Wu Daixuan , Yang Meilin , Bai Shuhuai , Huang Sitong , Wang Mingjing , Liu Ruinan , Li Zhaohui , Li Dan , Shen Yuecheng
Published: May 2023

Single-pixel imaging (SPI) is a computational imaging modality that reconstructs images from information collected with a single-pixel detector. Due to the relatively large bandwidth and cheap price of single-pixel detectors over pixel-array detectors, SPI has been demonstrated with great success in many imaging scenarios. In this work, we further extended SPI to microscopic Mueller-matrix polarimetry, which is capable of providing polarization-sensitive properties of biological tissue with a millimeter-size field of view and micrometer-size resolution. As a proof of concept, we applied polarimetry on normal and cancerous esophagus tissues from patients and reconstructed their Mueller matrices. Effects of depolarization, retardation, and diattenuation were also examined by decomposing Mueller matrices. We envision that the developed computational technique can bring new possibilities for both SPI and Mueller-matrix polarimetry.
Effects of polarizability and charge transfer on water dynamics and the underlying activation energies
Authors: Rick Steven W. , Thompson Ward H.
Published: May 2023

A large number of force fields have been proposed for describing the behavior of liquid water within classical atomistic simulations, particularly molecular dynamics. In the past two decades, models that incorporate molecular polarizability and even charge transfer have become more prevalent, in attempts to develop more accurate descriptions. These are frequently parameterized to reproduce the measured thermodynamics, phase behavior, and structure of water. On the other hand, the dynamics of water is rarely considered in the construction of these models, despite its importance in their ultimate applications. In this paper, we explore the structure and dynamics of polarizable and charge-transfer water models, with a focus on timescales that directly or indirectly relate to hydrogen bond (H-bond) making and breaking. Moreover, we use the recently developed fluctuation theory for dynamics to determine the temperature dependence of these properties to shed light on the driving forces. This approach provides key insight into the timescale activation energies through a rigorous decomposition into contributions from the different interactions, including polarization and charge transfer. The results show that charge transfer effects have a negligible effect on the activation energies. Furthermore, the same tension between electrostatic and van der Waals interactions that is found in fixed-charge water models also governs the behavior of polarizable models. The models are found to involve significant energy–entropy compensation, pointing to the importance of developing water models that accurately describe the temperature dependence of water structure and dynamics.
Continuum perturbation field in quiescent ambience: Common foundation of flows and acoustics
Authors: Sengupta Tapan K. , Jha Shivam K. , Sengupta Aditi , Joshi Bhavna , Sundaram Prasannabalaji
Published: May 2023

Here, the perturbation equation for a dissipative medium is derived from the first principles for the linearized compressible Navier–Stokes equation without Stokes' hypothesis. Dispersion relations of this generic governing equation are obtained, which exhibits both the dispersive and dissipative nature of perturbations traveling in a dissipative medium, depending upon the length scale. We specifically provide a theoretical cutoff wave number above which the perturbation equation represents diffusive and dissipative nature of the quiescent flow. It is shown that perturbation equations for pressure and velocity retain the same form in one-dimension, but it is not the same for multi-dimensional perturbation fields. Such behavior has not been reported before, as per the knowledge of the authors.
Mode purification for multimode Lamb waves by shunted piezoelectric unimorph array
Authors: Xia Rongyu , Wang Weihan , Shao Shixuan , Wu Zheng , Chen Jiyue , Zhang Xiaodong , Li Zheng
Published: May 2023

Guided wave-based nondestructive testing and structural health monitoring methods have been developed to exhibit attractive potentials and best prospects for rapid and sensitive detection of defects or damage in engineering structures. Different modes of guided waves can provide different sensitivities of damage detection. However, the multimode and mode conversion nature of guided waves poses significant challenges to mode purification of received signals. This study aims to design a metamaterial-based smart transducer for mode purification of Lamb waves in a plate, which can filter out an undesired mode of the Lamb wave to enhance sensing and actuating signals of a dominated mode. The smart transducer consists of a periodic array of shunted piezoelectric unimorphs with staggered polarization directions and is bonded on the surface of a host plate. Numerical and experimental results show that a local resonance bandgap for an anti-symmetric Lamb wave, rather than a symmetric Lamb wave, can be obtained and tuned through the shunting inductance circuit. Within such mode bandgap, the wave control for propagating a specific mode of the Lamb wave can be further realized, i.e., the mode of the Lamb wave is purified. The design presented herein offers enhanced capabilities in controlling guided wave propagation for engineering applications and nondestructive testing techniques.
Investigation of carrier transport through perovskite crystal junctions with in-situ replaceable electrodes
Authors: Zhao Zhibin , Zhang Zemin , Zhang Jieyi , Wang Mingwei , Li Yuelong , Xiang Dong
Published: May 2023

Metal electrode materials play a crucial role in determining the performance of microscale perovskite-based devices. However, it is a great challenge to in situ investigate the influence of different metal electrode materials on the performance of the same piece of a microscale perovskite due to the strong bonding between the perovskite and the electrode. To this end, a strategy to fabricate soft-sandwiched perovskite junctions by employing a liquid metal as top electrode was put forward. By taking full use of the adhesion of the top liquid metal electrode, the bottom electrode can be freely replaced by different metal materials without mechanical damage and chemical contamination. It is demonstrated that the shape of the instantaneous photocurrent upon light illumination and the rectification behavior of perovskite junctions can be controlled by the electrode materials and the light intensity. The shape of instantaneous photocurrent is mainly controlled by the light intensity rather than electrode materials. In contrast, the rectification ratio is mainly determined by the electrode materials instead of the light intensity. The underlying mechanism for these observations is elucidated based on the energy-level alignment in the junctions. The detachable soft junctions are expected to be widely applied to study the influence of external electrodes on the carrier transport of various microscale/nanoscale objects.
Informing ecosystem values of Loktak Lake in Manipur, India: an application of discrete choice experiments
Authors: Amarayil Sreeraman Binilkumar , Singh Konthoujam Gyanendra , Leichombam Prasanta
Published: May 2023

Context To inform the economic value of Loktak Lake, a Ramsar Site located in north-eastern India, and to suggest sustainable management and wise use of the Lake. Aim To find out the stakeholder preferences and the marginal willingness to pay over improved conservation and management of Loktak Lake. Method Choice Experiment Method, a stated preference method used for environmental valuation is employed in the study. Result The majority of the stakeholders have indicated their strong preference for effective conservation of the Lake with improvement in the fish catch and recreational sites as part of the improved conservation and management of the Lake. Conclusion The stakeholders’ preferences vary significantly in terms of the levels of improvement for different attributes. The high preference for increased fish catch and recreational sites indicated the importance of fish in the social and economic life of the households and scope of alternative employment opportunities respectively. But reduction of phumdi is not preferred as it is linked with the traditional fishing practices. Further, the local stakeholders do not prefer increased alternative employment opportunities, which may be attributed to the trust issues between the local stakeholders and wetland managers. Implication The livelihood options of the dependent communities should be integrated as part of the conservation and management policy of the Loktak Lake. It necessitates more inclusive wetland management or governance structure, and a framework needs to be developed with more local stakeholder participation and to develop site-specific employment generation or income generation schemes to reduce the dependence on the wetland. The participatory approach and continuous involvement of local communities in managing resources will help sustain the environment in the long run.
Subject agreement in control and modal constructions in Russian Sign Language
Authors: Khristoforova Evgeniia
Published: May 2023

The present research combines three fields of inquiry in sign language linguistics: verbal agreement, person features, and syntactic complexity. These topics have previously been addressed in isolation, but little is known about their interaction. This study attempts to fill this gap by investigating subject agreement in complement clauses in Russian Sign Language. By means of corpus investigation and grammaticality judgments, I found that subject agreement in clausal complements of the control predicatestry, love, want, begin, and modalcanmay be deficient – in particular, it can be reduced to the forms identical to first-person marking even in the case of a third-person subject controller. Deficient subject agreement in complement clauses is thus reminiscent of non-finite verbal forms in spoken languages. I further argue that the choice of first-person forms in deficient agreement reveals a default status of first person in sign languages, which is consistent with proposals regarding the modality-specific properties of first-person reference in these languages.
Exploring the Case Running as a Tool for Social Inclusion and Community Change in Cairo, Egypt
Authors: Elmahdy Yasmine M. , Sarhan Mahmoud , Elmahdy Amr
Published: May 2023

Introduction

This case study sheds light on the growing interest and community participation in recreational running in Cairo, the Capital of Egypt. It highlights the contribution of running groups in promoting social inclusion and fostering community change.

In this case study, students can learn about terms such as social inclusion and community change and how they are linked to sports and recreation. Students will also learn about the role of running groups in encouraging community participation in running, especially in less developed countries. Moreover, they will learn about the power of sports such as running in providing an entry point for the participation of women in leisure activities and creating opportunities for socially excluded individuals to be involved in society. The case study also explains how participation in running events promotes interaction and dialogue within the community and the exchange of ideas and experiences.

As introductory exercises, to become familiar with the subject, students can:

Through online research, learn about running in urban areas and streets in less developed countries, including Egypt. This includes exploring the current situation, opportunities, and challenges.

Explore the impact and contribution of running on improving social inclusion and community change.
Not just protons: Chloride also activates lysosomal acidic hydrolases
Authors: Feng Xinghua , Liu Siyu , Xu Haoxing
Published: May 2023

Lysosomal hydrolases require an acidic lumen for their optimal activities. In this issue, two independent groups (Wu et al. 2023. J. Cell Biol.https://doi.org/10.1083/jcb.202208155; Zhang et al. 2023. J. Cell. Biol.https://doi.org/10.1083/jcb.202210063) report that hydrolase activation also requires high intralysosomal Cl−, which is established by the lysosomal Cl−/H+ exchanger ClC-7.
Search for Ultralight Dark Matter with a Frequency Adjustable Diamagnetic Levitated Sensor
Authors: Li Rui , Lin Shaochun , Zhang Liang , Duan Changkui , Huang Pu , Du Jiangfeng
Published: May 2023

Among several dark matter candidates, bosonic ultra-light (sub-meV) dark matter is well motivated because it could couple to the Standard Model and induce new forces. Previous MICROSCOPE and Eöt–Wash torsion experiments have achieved high accuracy in the sub-1 Hz region. However, at higher frequencies there is still a lack of relevant experimental research. We propose an experimental scheme based on the diamagnetic levitated micromechanical oscillator, one of the most sensitive sensors for acceleration sensitivity below the kilohertz scale. In order to improve the measurement range, we utilize a sensor whose resonance frequency ω
0 could be adjusted from 0.1 Hz to 100 Hz. The limits of the coupling constant g

B–L
are improved by more than 10 times compared to previous reports, and it may be possible to achieve higher accuracy by using the array of sensors in the future.
Large-scale surface hopping simulation of charge transport in hexagonal molecular crystals: role of electronic coupling signs
Authors: Wang Zirui , Dong Jiawei , Wang Linjun
Published: May 2023

In large-scale surface hopping simulations with a huge number of electronic states, trivial crossings could easily lead to incorrect long-range charge transfer and induce large numerical errors. We here study the charge transport in two-dimensional hexagonal molecular crystals with a parameter-free full crossing corrected global flux surface hopping method. Fast time-step size convergence and system size independence have been realized in large systems containing thousands of molecular sites. In hexagonal systems, each molecular site has six nearest neighbours. We find that the signs of their electronic couplings have a strong impact on the charge mobility and delocalization strength. In particular, changing the signs of electronic couplings can even lead to a transition from hopping to band-like transport. In comparison, such phenomena cannot be observed in extensively studied two-dimensional square systems. This is attributed to symmetry of the electronic Hamiltonian and distribution of the energy levels. Due to its high performance, the proposed approach is promising to be applied to more realistic and complex systems for molecular design.
An efficient lightweight neural network using BiLSTM-SCN-CBAM with PCA-ICEEMDAN for diagnosing rolling bearing faults
Authors: You Keshun , Qiu Guangqi , Gu Yingkui
Published: May 2023

This study proposes an efficient rolling bearing fault diagnosis model of a hybrid neural network with a lightweight attention mechanism. Firstly, to achieve the low complexity of deep learning (DL) computation, data reduction and denoising are performed by sparse convolutional network (principal component analysis and improved complete ensemble empirical modal decomposition of adaptive noise), then processed data is imported to the hybrid neural network model with convolutional block attention module. The bi-directional long short-term memory and sparse convolutional networks are used in the backbone of the model. A lightweight, generalized attention mechanism is introduced to the last layer of the model for enhancing feature learning, which can further improve the diagnostic accuracy and efficiency. Compared with existing DL fault diagnosis models, In simulating the most realistic cross-conditions and cross-platform conditions, which leads to the random nature of fault generation and makes model diagnosis more complex, the proposed method still maintains less running time and excellent diagnostic accuracy. Finally, the experimental results fully prove that the model has reliable robust and efficient, and it achieves the best balance of diagnostic accuracy and diagnostic efficiency of the hybrid DL model.
Continuous estimation of kinetic variables while walking using an accelerometer and artificial neural networks
Authors: Mantashloo Zahed , Abbasi Ali , Tazji Mehdi Khaleghi , Pedram Mir Mohsen
Published: May 2023

Measuring the gait variables outside the laboratory is so important because they can be used to analyze walking in the long run and during real life situations. Wearable sensors like accelerometer show high potential in these applications. So, the aim of this study was continuous estimation of kinetic variables while walking using an accelerometer and artificial neural networks (ANNs). Seventy-three subjects (26 women and 47 men) voluntarily participated in this study. The subjects walked at the slow, moderate, and fast speeds on a walkway which covered with 10 Vicon camera. Acceleration was used as input for a feedforward neural networks to predict the lower limb moments (in sagittal, frontal, and transverse planes), power, and ground reaction force (GRF) (in medial-lateral, anterior-posterior, and vertical directions) during walking. Normalized root mean square error (nRMSE), and Pearson correlation coefficient (r) were computed between the measured and predicted variables. Statistical parametric mapping (SPM) was used to compare the measured and predicted variables. The results of this study showed approximately r values of 91–99 and nRMSE values of 4%–15% for GRF, power, and moment between the measured and predicted data. The SPM showed no significant difference between the measured and predicted variables in throughout stance phase. This work has shown the potential of predicting kinetic variables (GRF, moment, and power) in various speeds of walking using the accelerometer. The proposed estimation procedure utilizing a mixture of biomechanics and ANNs can be utilized to solve the tradeoff between richness of data and ease of measuring inherent in wearable sensors.
Bearing failure diagnosis at time-varying speed based on adaptive clustered fractional Gabor transform
Authors: Liu Fei , Shang Zhiwu , Gao Maosheng , Li Wanxiang , Pan Cailu
Published: May 2023

For bearing fault diagnosis at time-varying speed with tachometer-free and non-resampling, the crucial process is to obtain a high-resolution time-frequency representation and extract fault features. However, current multi-component non-stationary signal feature extraction methods based on time-frequency transform suffer from fixed parameter settings and insufficient resolution for low signal-to-noise ratio signals. To address these issues, a novel adaptive clustered fractional Gabor transform is proposed and applied to extract bearing fault features at time-varying speed. Firstly, the grey wolf optimization is utilized to adaptively search for the optimal fractional order and Gauss window length based on the maximum spectral kurtosis and the generalized time-bandwidth product to achieve the most adequate fractional Gabor spectrum (FrGS). Then, the Clustering by Fast Search and Find of Density Peaks algorithm reconstructs the sparse representation of the FrGS, remapping multi-component signals into single-component clusters. Bearing fault diagnosis is achieved by matching the relative order of each cluster with the bearing fault characteristic coefficients. Simulation signals validate the superiority of the feature extraction method, and experimental signals validate the feasibility of the bearing fault diagnosis method.
Pulse length dependence of a reactive high power impulse magnetron (HiPIMS) discharge
Authors: Hippler R , Cada M , Mutzke A , Hubicka Z
Published: May 2023

The pulse length dependence of a reactive high power impulse magnetron sputtering (HiPIMS) discharge with a tungsten cathode in an argon+oxygen gas mixture gas was investigated. The HiPIMS discharge is operated with a variable pulse length of 20–500 µs. Discharge current measurements, optical emission spectroscopy of neutral Ar, O, and W lines, and energy-resolved ion mass spectrometry are employed. A pronounced dependence of the discharge current on pulse length is noted while the initial discharge voltage is maintained constant. Energy-resolved mass spectrometry shows that the oxygen-to-tungsten (O+/W+) and the tungsten oxide-to-tungsten (WO+/W+) ion ratio decreases with pulse length due to target cleaning. Simulation results employing the SDTrimSP program show the formation of a non-stoichiometric sub-surface compound layer of oxygen which depends on the impinging ion composition and thus on the pulse length.
Long-lasting XUV activation of helium nanodroplets for avalanche ionization
Authors: Medina C , Lægdsmand A Ø , Ltaief L Ben , Hoque Z , Roos A H , Jurkovičová L , Hort O , Finke O , Albrecht M , Nejdl J , Stienkemeier F , Andreasson J , Klimešová E , Krikunova M , Heidenreich A , Mudrich M
Published: May 2023

We study the dynamics of avalanche ionization of pure helium nanodroplets activated by a weak extreme-ultraviolet (XUV) pulse and driven by an intense near-infrared (NIR) pulse. In addition to a transient enhancement of ignition of a nanoplasma at short delay times

∼

200

 fs, long-term activation of the nanodroplets lasting up to a few nanoseconds is observed. Molecular dynamics simulations suggest that the short-term activation is caused by the injection of seed electrons into the droplets by XUV photoemission. Long-term activation appears due to electrons remaining loosely bound to photoions which form stable ‘snowball’ structures in the droplets. Thus, we show that XUV irradiation can induce long-lasting changes of the strong-field optical properties of nanoparticles, potentially opening new routes to controlling avalanche-ionization phenomena in nanostructures and condensed-phase systems.
Network topology enables efficient response to environment in Physarum polycephalum
Authors: Chen Siyu , Alim Karen
Published: May 2023

The network-shaped body plan distinguishes the unicellular slime mould Physarum polycephalum in body architecture from other unicellular organisms. Yet, network-shaped body plans dominate branches of multi-cellular life such as in fungi. What survival advantage does a network structure provide when facing a dynamic environment with adverse conditions? Here, we probe how network topology impacts P. polycephalum’s avoidance response to an adverse blue light. We stimulate either an elongated, I-shaped amoeboid or a Y-shaped networked specimen and subsequently quantify the evacuation process of the light-exposed body part. The result shows that Y-shaped specimen complete the avoidance retraction in a comparable time frame, even slightly faster than I-shaped organisms, yet, at a lower almost negligible increase in migration velocity. Contraction amplitude driving mass motion is further only locally increased in Y-shaped specimen compared to I-shaped—providing further evidence that Y-shaped’s avoidance reaction is energetically more efficient than in I-shaped amoeboid organisms. The difference in the retraction behaviour suggests that the complexity of network topology provides a key advantage when encountering adverse environments. Our findings could lead to a better understanding of the transition from unicellular to multicellularity.
Homojunction structure amorphous oxide thin film transistors with ultra-high mobility
Authors: Lu Rongkai , Li Siqin , Lu Jianguo , Lu Bojing , Yang Ruqi , Lu Yangdan , Shao Wenyi , Zhao Yi , Zhu Liping , Zhuge Fei , Ye Zhizhen
Published: May 2023

Amorphous oxide semiconductors (AOS) have unique advantages in transparent and flexible thin film transistors (TFTs) applications, compared to low-temperature polycrystalline-Si (LTPS). However, intrinsic AOS TFTs are difficult to obtain field-effect mobility (μ
FE) higher than LTPS (100 cm2/(V·s)). Here, we design ZnAlSnO (ZATO) homojunction structure TFTs to obtain μ
FE = 113.8 cm2/(V·s). The device demonstrates optimized comprehensive electrical properties with an off-current of about 1.5 × 10–11 A, a threshold voltage of –1.71 V, and a subthreshold swing of 0.372 V/dec. There are two kinds of gradient coupled in the homojunction active layer, which are micro-crystallization and carrier suppressor concentration gradient distribution so that the device can reduce off-current and shift the threshold voltage positively while maintaining high field-effect mobility. Our research in the homojunction active layer points to a promising direction for obtaining excellent-performance AOS TFTs.
Optimizing the morphology of all-polymer solar cells for enhanced photovoltaic performance and thermal stability
Authors: An Kang , Zhong Wenkai , Zhu Chunguang , Peng Feng , Xu Lei , Lin Zhiwei , Wang Lei , Zhou Cheng , Ying Lei , Li Ning , Huang Fei
Published: May 2023

Due to the complicated film formation kinetics, morphology control remains a major challenge for the development of efficient and stable all-polymer solar cells (all-PSCs). To overcome this obstacle, the sequential deposition method is used to fabricate the photoactive layers of all-PSCs comprising a polymer donor PTzBI-oF and a polymer acceptor PS1. The film morphology can be manipulated by incorporating amounts of a dibenzyl ether additive into the PS1 layer. Detailed morphology investigations by grazing incidence wide-angle X-ray scattering and a transmission electron microscope reveal that the combination merits of sequential deposition and DBE additive can render favorable crystalline properties as well as phase separation for PTzBI-oF:PS1 blends. Consequently, the optimized all-PSCs delivered an enhanced power conversion efficiency (PCE) of 15.21% along with improved carrier extraction and suppressed charge recombination. More importantly, the optimized all-PSCs remain over 90% of their initial PCEs under continuous thermal stress at 65 °C for over 500 h. This work validates that control over microstructure morphology via a sequential deposition process is a promising strategy for fabricating highly efficient and stable all-PSCs.
One-photo excitation pathway in 2D in-plane heterostructures for effective visible-light-driven photocatalytic degradation
Authors: Liu Mengchi , Cheng Yiwen , Xie Yuee , Wei Yingcong , Xing Jinhui , Chen Yuanping , Xu Jing
Published: May 2023

Broad-spectrum absorption and highly effective charge-carrier separation are two essential requirements to improve the photocatalytic performance of semiconductor-based photocatalysts. In this work, a fascinating one-photon system is reported by rationally fabricating 2D in-plane Bi2O3/BiOCl (i-Cl) heterostructures for efficient photocatalytic degradation of RhB and TC. Systematic investigations revealed that the matched band structure generated an internal electric field and a chemical bond connection between the Bi2O3 and BiOCl in the Bi2O3/BiOCl composite that could effectively improve the utilization ratio of visible light and the separation effectivity of photo-generated carriers in space. The formed interactions at the 2D in-plane heterojunction interface induced the one-photon excitation pathway which has been confirmed by the experiment and DFT calculations. As a result, the i-Cl samples showed significantly enhanced photocatalytic efficiency towards the degradation of RhB and TC (RhB: 0.106 min−1; TC: 0.048 min−1) under visible light. The degradation activities of RhB and TC for i-Cl were 265.08 and 4.08 times that of pure BiOCl, as well as 9.27 and 2.14 times that of mechanistically mixed Bi2O3/BiOCl samples, respectively. This work provides a logical strategy to construct other 2D in-plane heterojunctions with a one-photon excitation pathway with enhanced performance.
A novel SiC high-k superjunction power MOSFET integrated Schottky barrier diode with improved forward and reverse performance
Authors: Kong Moufu , Hu Zewei , Yan Ronghe , Yi Bo , Zhang Bingke , Yang Hongqiang
Published: May 2023

A new SiC superjunction power MOSFET device using high-k insulator and p-type pillar with an integrated Schottky barrier diode (Hk-SJ-SBD MOSFET) is proposed, and has been compared with the SiC high-k MOSFET (Hk MOSFET), SiC superjuction MOSFET (SJ MOSFET) and the conventional SiC MOSFET in this article. In the proposed SiC Hk-SJ-SBD MOSFET, under the combined action of the p-type region and the Hk dielectric layer in the drift region, the concentration of the N-drift region and the current spreading layer can be increased to achieve an ultra-low specific on-resistance (R
on,sp). The integrated Schottky barrier diode (SBD) also greatly improves the reverse recovery performance of the device. TCAD simulation results indicate that the R
on,sp of the proposed SiC Hk-SJ-SBD MOSFET is 0.67 mΩ·cm2 with a 2240 V breakdown voltage (BV), which is more than 72.4%, 23%, 5.6% lower than that of the conventional SiC MOSFET, Hk SiC MOSFET and SJ SiC MOSFET with the 1950, 2220, and 2220 V BV, respectively. The reverse recovery time and reverse recovery charge of the proposed MOSFET is 16 ns and18 nC, which are greatly reduced by more than 74% and 94% in comparison with those of all the conventional SiC MOSFET, Hk SiC MOSFET and SJ SiC MOSFET, due to the integrated SBD in the proposed MOSFET. And the trade-off relationship between the R
on,sp and the BV is also significantly improved compared with that of the conventional MOSFET, Hk MOSFET and SJ MOSFET as well as the MOSFETs in other previous literature, respectively. In addition, compared with conventional SJ SiC MOSFET, the proposed SiC MOSFET has better immunity to charge imbalance, which may bring great application prospects.
Suitable contacting scheme for evaluating electrical properties of GaN-based p-type layers
Authors: Huang Siyi , Ikeda Masao , Zhang Minglong , Zhu Jianjun , Liu Jianping
Published: May 2023

A suitable contacting scheme for p-(Al)GaN facilitating quick feedback and accurate measurements is proposed in this study. 22 nm p+-GaN followed by 2 nm p-In0.2Ga0.8N was grown on p-type layers by metal-organic chemical vapor deposition. Samples were then cut into squares after annealing and contact electrodes using In balls were put at the corners of the squares. Good linearity between all the electrodes was confirmed in I–V curves during Hall measurements even with In metal. Serval samples taken from the same wafer showed small standard deviation of ~ 4% for resistivity, Hall mobility and hole concentration. The influence of contact layer on the electrical characteristics of bulk p-type layers was then investigated by step etching technique using inductively coupled plasma etching and subsequent Hall-effect measurements. Identical values could be obtained consistently when a 28 nm non-conductive layer thickness at the surface was taken into account. Therefore, the procedures for evaluating the electrical properties of GaN-based p-type layers just using In balls proposed in this study are shown to be quick and useful as for the other conventional III–V materials.