bluuebunny/crossref_metadata_2025 huggingface dataset:
An atom-in-molecule adaptive polarized valence single-ζ atomic orbital basis for electronic structure calculations
Authors: Müller Marcel , Hansen Andreas , Grimme Stefan
Published: October 2023

Many low-cost or semiempirical quantum mechanical-based electronic structure methods suffer from the use of unpolarized minimal atomic orbital (AO) basis sets. In this work, we overcome this limitation by a fully DFT variationally optimized, adaptive minimal basis set consistently available for the elements up to radon (Z = 86). The new key feature is to make the linear coefficients of the primitive Gaussians in a contracted AO dependent on the effective atomic charge of the atom in the molecule, i.e., each symmetry-unique atom obtains its “own” specifically adapted basis functions. In this way, the physically important “breathing” of the AOs in a molecule with (a) atomic charge (expansion/contraction for anionic/cationic states) and (b) the number of close-lying bonded neighbor atoms is accounted for. The required atomic charges are obtained from a specially developed extended Hückel type Hamiltonian and the coordination numbers from the molecule geometry. Proper analytical derivatives of the resulting adaptive basis functions can easily be derived. Moreover, the basis functions are electric field-dependent, thus improving the description of, e.g., dipole moments and polarizabilities. The new basis set termed q-vSZP (charge dependent valence single-ζ, polarized) is thoroughly benchmarked for atomic/molecular and thermochemical properties compared to standard minimal and double-ζ basis sets at the DFT level with the accurate ωB97X-D4 functional. It is shown that q-vSZP is clearly superior to existing minimal basis sets, often reaching double-ζ quality or even better results. We expect it to be the optimal choice in future semiempirical quantum mechanical methods.
Analytical solution for the Rayleigh–Plesset equation by Weierstrass elliptic equation
Authors: Guo Kaitao
Published: October 2023

The nonlinear dynamics of cavitation bubbles are studied theoretically through the Rayleigh–Plesset equation. A direct approach is first proposed to construct an analytical solution for cavitation bubbles. In particular, when considering the gas bubbles, we show the connection between the bubble motion and Weierstrass elliptic equation with the help of Sandman transformation. To the best of our knowledge, this is the first time that an elliptic function has been used to construct the parametric analytical solution for this case. The present findings would be significant in understanding the complex behavior of cavitation bubbles in practical applications, especially when considering the surface tension.
Penetrating gunshots to the head after close-range shooting: Dynamics of waves and the effect of brain tissue rheology
Authors: Kosmerl V. , Yarin A. L.
Published: October 2023

Formation of the brain tissue backspatter after penetrating gunshots to the head is preceded and driven by formation and evolution of the bullet channel, which is filling with air and/or muzzle gases or issuing them with tissue fragments or without them. This process is explored here in a model situation in the framework of the dynamics of waves in brain tissue affected by its realistic rheological behavior, fragmentation, and gas dynamics in the evolving bullet channel. As a rheological model of the brain tissue, a new strain-energy function W, introduced in the accompanying work, is employed, which expresses the strain energy as a rational function of the principal invariants of the Cauchy tensor C. This strain-energy function W generates a hyperelastic constitutive equation, which resembles the behavior of brain tissues, i.e., reveals a much stronger resistance to compression than to stretching and strongly nonlinear response in simple shear. This new rheological model belongs to the class of hyperelastic models used for description of hydrogels. The equations of motion supplemented by this rheological model reveal the dynamics of the compression and rarefaction waves propagating through the brain tissue following the formation of the bullet channel. These waves are reflected from the skull and the bullet channel. In parallel, gas dynamics of air and/or muzzle gases flowing into or issued outward of the bullet channel, and stretching-driven fragmentation of the brain tissue are evolving in concert with the wave dynamics in the brain tissue. This allows for prediction of backspatter of the brain tissue resulting from a short-range shooting.
RotGT-2023: A benchmark data set of rotational g tensors
Authors: Vishnevskiy Yury V.
Published: October 2023

The largest ever set, RotGT-2023, of statistically validated experimental components of rotational g tensors and respective vibrational corrections, has been created. The experimental values were collected from literature data. The vibrational corrections for obtaining equilibrium molecular g values have been calculated at the highest affordable coupled cluster level of theory. The set comprises 278 parameters from 129 molecules, including their isotopologues. Statistical assessment of the data has been performed to exclude unreliable parameters. A benchmarking of two theoretical approximations, based on coupled cluster and density functional theories, has been performed. The determined weighted mean and weighted standard deviations of the relative errors in calculated equilibrium g values are 1.09% and 2.07% for the ae-CCSD(T)/x2c-TZVPPall-s//ae-CCSD(T)/cc-pwCVTZ level. The obtained results can be used for predicting the rotational Zeeman effect, correcting rotational constants in spectroscopic studies and in molecular structure refinements. The latter has been demonstrated on the refinement of the molecular structure of silane SiH4, which resulted in rese(Si–H) = 1.473 323 1(27) Å. The other tested theoretical protocol, PBE0/x2c-TZVPPall-s//PBE0-D3BJ/def2-QZVPP, showed considerably worse statistical properties. The RotGT-2023 data set and the developed in this work statistical model are recommended for benchmarking of theoretical approximations for calculations of molecular magnetic properties.
Extending Schottky–Mott rule to van der Waals heterostructures of 2D Janus materials: Influence of intrinsic dipoles
Authors: Chen Wu-Yu , Li Lei , Huang Tao , Yang Zi-Xuan , Zhang Tao , Huang Gui-Fang , Hu Wangyu , Huang Wei-Qing
Published: October 2023

The Schottky–Mott (S–M) limit based on the S–M rule is often used to evaluate the Schottky barrier height (SBH) at metal–semiconductor (MS) van der Waals (vdW) contacts but fails at the polar interfaces. In order to extend the S–M rule to the polar interfaces, we here modify the S–M equation to predict the SBH at vdW interfaces of 2D Janus materials, taking into account the effects of intrinsic and interface dipoles. The modified S–M equation is verified based on the first-principles calculations of the MoSi2As2P2/HTaSe2F vdW interfaces, showing a sharp dependence of SBH on the dipole amplitude and direction. Specifically, n-type Schottky barriers tend to form when a semiconductor contacts with a low-work-function surface of Janus metal or a metal interfaces to the high-electron-affinity surface of Janus semiconductor; otherwise, a p-type one is preferable. Interestingly, the smallest n(p)-type SBH could be attained when both intrinsic dipole directions are the same. This work demonstrates that the S–M rule can be extended to the polar interfaces and dipole engineering is an effective strategy to tune the SBH at the MS interface.
Uncertainty quantification of nonlinear vibration response of the oscillator with double-sided unilateral spring
Authors: Li Yelin , Zheng Zhaoli
Published: October 2023

The oscillator with a double-sided unilateral spring is a common nonlinear system that widely exists in the industry. In order to deepen the understanding of its vibration characteristics, uncertainty quantification is carried out. The uncertain responses of systems with multi-solution phenomena are difficult to be investigated by the non-intrusive interval method. Thus, a surrogate model based on normalized frequency is proposed. First, the solution of the vibration response is calculated by the harmonic balance method and the arc-length method. Then, the normalized frequency is proposed to transform the multi-solution problem into a single solution problem, which makes the uncertainty quantification easy to be carried out. Finally, the effects of different types of uncertain cases on the nonlinear responses of the oscillator with a double-sided unilateral spring are obtained.
Driven transport of active particles through arrays of symmetric obstacles
Authors: Nayak Shubhadip , Das Sohom , Bag Poulami , Debnath Tanwi , Ghosh Pulak K.
Published: October 2023

We numerically examine the driven transport of an overdamped self-propelled particle through a two-dimensional array of circular obstacles. A detailed analysis of transport quantifiers (mobility and diffusivity) has been performed for two types of channels, channel I and channel II, that respectively correspond to the parallel and diagonal drives with respect to the array axis. Our simulation results show that the signatures of pinning actions and depinning processes in the array of obstacles are manifested through excess diffusion peaks or sudden drops in diffusivity, and abrupt jumps in mobility with varying amplitude of the drive. The underlying depinning mechanisms and the associated threshold driving strength largely depend on the persistent length of self-propulsion. For low driving strength, both diffusivity and mobility are noticeably suppressed by the array of obstacles, irrespective of the self-propulsion parameters and direction of the drive. When self-propulsion length is larger than a channel compartment size, transport quantifiers are insensitive to the rotational relaxation time. Transport with diagonal drives features self-propulsion-dependent negative differential mobility. The amplitude of the negative differential mobility of an active particle is much larger than that of a passive one. The present analysis aims at understanding the driven transport of active species like, bacteria, virus, Janus particle etc. in porous medium.
Comparing two sources of physical aging: Temperature vs electric field
Authors: Gabriel Jan P. , Richert Ranko
Published: October 2023

Physical aging is the process of a system evolving toward a new equilibrium, and thus the response to a change in external parameters such as temperature T, pressure p, or static electric field E. Using a static electric field has been shown to access physical aging above the glass transition temperature Tg, in the regime of milliseconds or faster, but the relation to its temperature jump counterpart has not been investigated to date. This work compares temperature and field induced physical aging in the limit of small perturbations for supercooled tributyl phosphate. It is found that both structural recovery dynamics are very similar, and that they match the collective reorientational dynamics as observed by dielectric relaxation. The results facilitate expanding the range of aging experiments to well above Tg, where a comparison with structural relaxation in equilibrium is straightforward, thus improving models of structural recovery and physical aging.
Postpartum contraception in Australia: opportunities for increasing access in the primary care setting
Authors: Singh Rhea , Botfield Jessica R.
Published: October 2023

In Australia, 20% of pregnancies occur within the first year after birth and most are unintended. Both unintended pregnancies and short interpregnancy intervals (<12–18 months) can have adverse effects on maternal, infant, and child health. Access to postpartum contraception reduces the risk of unintended pregnancies and short interpregnancy intervals, and supports women in pregnancy planning and birth spacing. In this forum article, we describe how postpartum contraception is currently provided in Australia and highlight opportunities for improving access in the primary care setting.
Predictions and rewards affect decision-making but not subjective experience
Authors: Sánchez-Fuenzalida Nicolás , van Gaal Simon , Fleming Stephen M. , Haaf Julia M. , Fahrenfort Johannes J.
Published: October 2023

To survive, organisms constantly make decisions to avoid danger and maximize rewards in information-rich environments. As a result, decisions about sensory input are not only driven by sensory information but also by other factors, such as the expected rewards of a decision (known as the payoff matrix) or by information about temporal regularities in the environment (known as cognitive priors or predictions). However, it is unknown to what extent these different types of information affect subjective experience or whether they merely result in nonperceptual response criterion shifts. To investigate this question, we used three carefully matched manipulations that typically result in behavioral shifts in decision criteria: a visual illusion (Müller-Lyer condition), a punishment scheme (payoff condition), and a change in the ratio of relevant stimuli (base rate condition). To gauge shifts in subjective experience, we introduce a task in which participants not only make decisions about what they have just seen but are also asked to reproduce their experience of a target stimulus. Using Bayesian ordinal modeling, we show that each of these three manipulations affects the decision criterion as intended but that the visual illusion uniquely affects sensory experience as measured by reproduction. In a series of follow-up experiments, we use computational modeling to show that although the visual illusion results in a distinct drift-diffusion (DDM) parameter profile relative to nonsensory manipulations, reliance on DDM parameter estimates alone is not sufficient to ascertain whether a given manipulation is perceptual or nonperceptual.
Two-fluid dynamics and micron-thin boundary layers shape cytoplasmic flows in earlyDrosophilaembryos
Authors: Hernández-López Claudio , Puliafito Alberto , Xu Yitong , Lu Ziqi , Di Talia Stefano , Vergassola Massimo
Published: October 2023

Cytoplasmic flows are widely emerging as key functional players in development. In earlyDrosophilaembryos, flows drive the spreading of nuclei across the embryo. Here, we combine hydrodynamic modeling with quantitative imaging to develop a two-fluid model that features an active actomyosin gel and a passive viscous cytosol. Gel contractility is controlled by the cell cycle oscillator, the two fluids being coupled by friction. In addition to recapitulating experimental flow patterns, our model explains observations that remained elusive and makes a series of predictions. First, the model captures the vorticity of cytosolic flows, which highlights deviations from Stokes’ flow that were observed experimentally but remained unexplained. Second, the model reveals strong differences in the gel and cytosol motion. In particular, a micron-sized boundary layer is predicted close to the cortex, where the gel slides tangentially while the cytosolic flow cannot slip. Third, the model unveils a mechanism that stabilizes the spreading of nuclei with respect to perturbations of their initial positions. This self-correcting mechanism is argued to be functionally important for proper nuclear spreading. Fourth, we use our model to analyze the effects of flows on the transport of the morphogen Bicoid and the establishment of its gradients. Finally, the model predicts that the flow strength should be reduced if the shape of the domain is more round, which is experimentally confirmed inDrosophilamutants. Thus, our two-fluid model explains flows and nuclear positioning in earlyDrosophila, while making predictions that suggest novel future experiments.
Inhaled mRNA nanoparticles dual-targeting cancer cells and macrophages in the lung for effective transfection
Authors: Tang Zhongmin , You Xinru , Xiao Yufen , Chen Wei , Li Yongjiang , Huang Xiangang , Liu Haijun , Xiao Fan , Liu Chuang , Koo Seyoung , Kong Na , Tao Wei
Published: October 2023

Messenger RNA (mRNA)–based therapeutics are transforming the landscapes of medicine, yet targeted delivery of mRNA to specific cell types while minimizing off-target accumulation remains challenging for mRNA-mediated therapy. In this study, we report an innovative design of a cationic lipid- and hyaluronic acid–based, dual-targeted mRNA nanoformulation that can display the desirable stability and efficiently transfect the targeted proteins into lung tissues. More importantly, the optimized dual-targeted mRNA nanoparticles (NPs) can not only accumulate primarily in lung tumor cells and inflammatory macrophages after inhalation delivery but also efficiently express any desirable proteins (e.g., p53 tumor suppressor for therapy, as well as luciferase and green fluorescence protein for imaging as examples in this study) and achieve efficacious lung tissue transfection in vivo. Overall, our findings provide proof-of-principle evidence for the design and use of dual-targeted mRNA NPs in homing to specific cell types to up-regulate target proteins in lung tissues, which may hold great potential for the future development of mRNA-based inhaled medicines or vaccines in treating various lung-related diseases.
A small-molecule inhibitor of TopBP1 exerts anti-MYC activity and synergy with PARP inhibitors
Authors: Lin Fang-Tsyr , Liu Kang , Garan Lidija A. Wilhelms , Folly-Kossi Helena , Song Yongcheng , Lin Shwu-Jiuan , Lin Weei-Chin
Published: October 2023

We have previously identified TopBP1 (topoisomerase IIβ-binding protein 1) as a promising target for cancer therapy, given its role in the convergence of Rb, PI(3)K/Akt, and p53 pathways. Based on this, we conducted a large-scale molecular docking screening to identify a small-molecule inhibitor that specifically targets the BRCT7/8 domains of TopBP1, which we have named 5D4. Our studies show that 5D4 inhibits TopBP1 interactions with E2F1, mutant p53, and Cancerous Inhibitor of Protein Phosphatase 2A. This leads to the activation of E2F1-mediated apoptosis and the inhibition of mutant p53 gain of function. In addition, 5D4 disrupts the interaction of TopBP1 with MIZ1, which in turn allows MIZ1 to bind to its target gene promoters and repress MYC activity. Moreover, 5D4 inhibits the association of the TopBP1-PLK1 complex and prevents the formation of Rad51 foci. When combined with inhibitors of PARP1/2 or PARP14, 5D4 synergizes to effectively block cancer cell proliferation. Our animal studies have demonstrated the antitumor activity of 5D4 in breast and ovarian cancer xenograft models. Moreover, the effectiveness of 5D4 is further enhanced when combined with a PARP1/2 inhibitor talazoparib. Taken together, our findings strongly support the potential use of TopBP1-BRCT7/8 inhibitors as a targeted cancer therapy.
Topological Plasma Transport from a Diffusion View
Authors: Liu 刘 Zhoufei 周费 , Huang 黄 Jiping 吉平
Published: October 2023

Recent studies have identified plasma as a topological material. Yet, these researches often depict plasma as a fluid governed by electromagnetic fields, i.e., a classical wave system. Indeed, plasma transport can be characterized by a unique diffusion process distinguished by its collective behaviors. We adopt a simplified diffusion-migration method to elucidate the topological plasma transport. Drawing parallels to the thermal conduction-convection system, we introduce a double-ring model to investigate the plasma density behaviors in the anti-parity-time reversal (APT) unbroken and broken phases. Subsequently, by augmenting the number of rings, we have established a coupled ring chain structure. This structure serves as a medium for realizing the APT symmetric one-dimensional (1D) reciprocal model, representing the simplest tight-binding model with a trivial topology. To develop a model featuring topological properties, we should modify the APT symmetric 1D reciprocal model from the following two aspects: hopping amplitude and onsite potential. From the hopping amplitude, we incorporate the non-reciprocity to facilitate the non-Hermitian skin effect, an intrinsic non-Hermitian topology. Meanwhile, from the onsite potential, the quasiperiodic modulation has been adopted onto the APT symmetric 1D reciprocal model. This APT symmetric 1D Aubry–André–Harper model is of topological nature. Additionally, we suggest the potential applications for these diffusive plasma topological states. This study establishes a diffusion-based approach to realize topological states in plasma, potentially inspiring further advancements in plasma physics.
Quantum computing with trapped ions: a beginner’s guide
Authors: Bernardini Francesco , Chakraborty Abhijit , Ordóñez Carlos R
Published: October 2023

This pedagogical article elucidates the fundamentals of trapped-ion quantum computing, which is one of the potential platforms for constructing a scalable quantum computer. The evaluation of a trapped-ion system’s viability for quantum computing is conducted in accordance with DiVincenzo’s criteria.
Should you walk, run or sprint in the rain to get less wet?
Authors: Zaegel Matteo , Vehils-Vinals Mathis , Guastalla Hugo , Benabou Benjamin , Gires Auguste
Published: October 2023

We have all wondered once whether we should walk, run or sprint in the rain in order to stay as dry as possible. Previous publications already addressed this subject using simple models, as for the shape of the body and the description of the rain and wind. This paper presents a detailed approach which relies on a more realistic ‘human body’ shape and accounts for the variability in time of both the wind and the raindrop size and velocity distributions. It appears that in some seldom cases with tailwind and light rain, there is an optimum velocity, but in general it is better to run as fast as possible. While ‘running’ instead of ‘walking’ yields significant gain, the extra effort required to ‘sprint’ is not always worth it.
Anomalous Hall effect in naturally oxidized normal-metal Al/Cu double films
Authors: Zhao Lijuan , Li Yuzhi , Wang Yongzuo , Chen Peng , lv Bing , Gao Cunxu
Published: October 2023

An unexpectedly larger current-induced spin–orbit torque in oxidized Cu (CuO
x
)/ferromagnet (FM) than heavy-metal/FM has recently attracted intense attention in spintronic studies. Although the two mechanisms, interfacial Rashba Edelstein effect and spin-vorticity coupling, have been put forward based on the two different conductive features of CuO
x
, i.e. electrical insulator and gradient of electrical mobility, the detailed investigation of transport of CuO
x
is still lacking. Here we experimentally report the positive and negative anomalous Hall effect (AHE) in naturally oxidized normal-metal Al/Cu double films. We found that the onset temperature of AHE corresponds to magnetic transition temperature of CuO
x
. Furthermore, by comparing Hall resistance of the crystalline and amorphous Cu/Al double films, we identify that the positive anomalous Hall resistance attributes to magnetic moment of CuO
x
itself, while the negative anomalous Hall resistance can originate from the spin or orbital currents generated at the CuO
x
/AlO
x
interface interact with magnetization of CuO
x
and its inverse process.
Study on muon MDM and lepton EDM in BLMSSM via the mass insertion approximation
Authors: Wang Xi , Long Xin-Xin , Wang Yi-Tong , Wang Tong-Tong , Zhang Hai-Bin , Feng Tai-Fu , Zhang Rong-Xiang , Zhao Shu-Min
Published: October 2023

In the framework of the MSSM extension with local gauged baryon and lepton numbers (BLMSSM), we calculate the muon anomalous magnetic dipole moment (MDM) and lepton (e, μ, τ) electric dipole moment (EDM), and discuss how the muon MDM and lepton EDM depend on the parameters within the mass insertion approximation. Among many parameters,

tan
β

, g

L
, m

L
and μ

H
are more sensitive parameters for

a
μ
BL

. Considering the experimental limitations, our best numerical result of

a
μ
BL

is around 2.5 × 10−9, which can well compensate the departure between the experiment data and standard model (SM) prediction. The CP violating phases in BLMSSM are more than those in the MSSM, including new parameters

θ

μ

L

and θ

L
. They can give large contributions, which play an important role in exploring the source of CP violation and probing new physics beyond SM.
First-principles study of magnetic interactions and excitations in antiferromagnetic van der Waals material MPX3 (M=Mn, Fe, Co, Ni; X=S, Se)
Authors: Yan Songsong , Du Yongping , Zhang Xiaoou , Wan Xiangang , Wang Di
Published: October 2023

Transition metal phosphorus trichalcogenides MPX3 (M = Mn, Fe, Co, Ni; X = S, Se), as layered van der Waals antiferromagnetic (AFM) materials, have emerged as a promising platform for exploring two-dimensional (2D) magnetism. Based on density functional theory, we present a comprehensive investigation of the electronic and magnetic properties of MPX3. We calculated the spin exchange interactions as well as magnetocrystalline anisotropy energy. The numerical results reveal that J
3 is AFM in all cases, and J
2 is significantly smaller compared to both J
3 and J
1. This behavior can be understood with regard to exchange paths and electron filling. Compared to other materials within this family, FePS3 and CoPS3 demonstrate significant easy-axis anisotropy. Using the obtained parameters, we estimated the Néel temperature T

N
and Curie-Weiss temperature

θ

C
W

, and the results are in good agreement with the experimental observations. We further calculated the magnon spectra and successfully reproduce several typical features observed experimentally. Finally, we give helpful suggestions for the strong constraints about the range of non-negligible magnetic interactions based on the relations between magnon eigenvalues at high-symmetry k points in honeycomb lattices.
Observation of plasmon excitation in liquid silicon by inelastic x-ray scattering
Authors: Matsuda Kazuhiro , Ishiguro Yotaro , Kimura Koji , Hagiya Toru , Kajihara Yukio , Nagaya Kiyonobu , Inui Masanori , Hiraoka Nozomu
Published: October 2023

Inelastic x-ray scattering (IXS) measurements were performed for observing the excitation of bulk plasmons in metallic liquid silicon (Si). The peak due to plasmon excitation was observed within the energy loss around 17 eV. Combined with IXS data of crystalline Si measured at several elevated temperatures, it was found that temperature dependence of the excitation energy in the crystalline solid state is explained by the electron gas including the band gap effect, whereas in the metallic liquid state near the melting point, it exhibits a departure from the electron gas; the plasmon energy takes a lower value than that of the electron gas. Such lowering of plasmon energies is reasonably explained by a model incorporating semiconducting component to the electron gas. Non-simple metallic nature in liquid silicon is highlighted by the observation of electron collective dynamics.
Nonlinear characterization of enhanced and generalized Hjorth’s feature space for bearing condition monitoring
Authors: Li Wei , Wang Yi , Lv Feng , Zhang Guangyao , Ding Jiakai
Published: October 2023

The degradation assessment of rolling bearings provides a reasonable maintenance plan for the safe operation of mechanical equipment. The general strategy for bearing condition monitoring is to construct a health indicator (HI) to characterize different degradation stages. A preferable HI that can sensitively detect initial faults and track machine degradation is crucial to developing timely maintenance strategies for mechanical equipment to avoid catastrophic accidents. However, many developed and reported HIs are still insensitive to early faults, resulting in delayed maintenance schedules. To identify the incipient defects as early as possible, a novel HI constructed by nonlinear characterization of enhanced and generalized Hjorth’s feature space based on extended probability entropy is proposed in this paper. Firstly, the time-frequency spectral amplitude modulation helps to enhance the characteristics of the original signal with the amplitude editing in the time-frequency domain. Then, three new features of generalized Hjorth’s parameter combinations are designed and combined with other similar feature combinations to construct a high-dimensional enhanced and generalized Hjorth’s feature space. On this basis, a set of low-dimensional sensitive features is obtained by nonlinearly characterizing high-dimensional features through extended probability entropy after these features are standardized. Finally, a novel HI is developed by calculating the distance between the minimum volume ellipse (MVE) center of the low-dimensional feature subspace based on nonlinear characterization and the low-dimensional feature vector of the real-time monitoring signal. The performance of the proposed approach is verified in three cases, whose experimental results indicate that the proposed HI is more sensitive and significant in detecting early faults compared to some current HIs.
A novel vision transformer network for rolling bearing remaining useful life prediction
Authors: Hu Aijun , Zhu Yancheng , Liu Suixian , Xing Lei , Xiang Ling
Published: October 2023

The accurate predictions of remaining useful life (RUL) have become a key and extremely challenging problem. Due to the limitations of the classical convolutional neural network and recurrent neural network structure, the attention mechanism has been introduced to improve feature representation of the long-term bearing degradation data. Transformer network based on attention mechanism is successfully applied in many fields and recognized as an excellent creation for deep learning models. In this paper, a novel lightweight mobile vision transformer (MobileViT) architecture based on deep networks is proposed for the RUL predictions. This new network is named prognostics separable vision Transformer (ProgSViT), which combines the separable convolution and MobileViT. In ProgSViT network, the separable convolutions are first constructed for extracting local feature from the input vibration signal, and the new vision transformer architecture is proposed to learn the global feature representations. In improved MobileViT model, the loss function is optimized, and a new training strategy is provided. Finally, the obtained features are input to the global average pool layers and the full connection layers to perform RUL estimation. Experiment results present the proposed ProgSViT network surpasses the other models in RUL predicting, which possesses higher precision and computational efficiency.
Bidimensional local characteristic-scale decomposition and its application in gear surface defect detection
Authors: Liu Dongxu , Cheng Junsheng , Wu Zhantao
Published: October 2023

Visual image-based inspection methods can directly reflect the type of defects on the surface of gears. However, these methods have many problems: firstly, as a two-dimensional signal, the data volume of images is large and the processing is relatively time-consuming. Although some existing image signal processing methods (e.g. bidimensional empirical mode decomposition (BEMD)) have good decomposition results, their decomposition speed is slow. The bidimensional local characteristic-scale decomposition (BLCD) method is proposed in this paper, which adaptively decomposes an image from high to low frequencies into several bidimensional intrinsic scale components. It is demonstrated that the BLCD method maintains the advantages of the BEMD method in terms of good decomposition ability and adaptive capability while significantly reducing the processing time and improving the computational efficiency. Secondly, in the running state of the gears, the obtained images sometimes contain noise, which is not convenient for detecting surface defect types. A gear surface defect detection method based on BLCD image denoising is proposed in this paper. Firstly, it uses the BLCD denoising module for preprocessing to provide high signal-to-noise ratio images for the subsequent detection module, and then uses the detection module for defect identification and classification. Experiments prove that the BLCD denoising module has excellent performance and it is well coupled with the detection module, giving the whole method higher accuracy and stability than other classification methods.
Van der Waals heterostructure gas sensors based on narrow–wide bandgap semiconductors for superior sensitivity
Authors: Gan Wei , Jiang Ming , Liu Yucheng , Ming Li , Xiao Ruichun , Tang Xi , Liu Yu , Long Dunxu , Zhao Changhui , Li Hui
Published: October 2023

Achieving high sensitivity in gas sensors is crucial for the precise detection of toxic agents. However, this can be challenging as it requires gas sensors to possess both a high response signal and low electrical noise simultaneously, which seems controversial as it necessitates adopting semiconductors with different bandgaps. Herein, we demonstrate the superior sensitivity of 2D molybdenum disulfide (MoS2)/tellurium (Te) van der Waals heterostructure (vdWH) gas sensors fabricated by combining narrow-bandgap (Te) and wide-bandgap (MoS2) semiconductors. The as-fabricated MoS2/Te vdWH gas sensors exhibit excellent sensitivity that is unavailable for sensors based on its individual counterparts. The response toward 50 ppm NH3 is improved by two and six times compared to the individual MoS2 and Te gas sensors, respectively. In addition, a high signal-to-noise ratio of ∼350 and an ultralow limit of detection of ∼2 ppb are achieved. These results outperform most previously reported gas sensors due to the efficient modulation of the barrier height of the MoS2/Te p–n junction as well as the synergistic effect benefiting from the low electric noise of the narrow-bandgap Te and high response signal of the wide-bandgap MoS2. Our work provides an insight into utilizing vdWHs based on narrow–wide bandgap semiconductors for developing highly sensitive gas sensors.
P–N heterojunction NiO/ZnO nanowire based electrode for asymmetric supercapacitor applications
Authors: Ahmad Reyaz , Sohail Aamir , Yousuf Mahvesh , Majeed Asif , Mir Arshid , Aalim Malik , Shah M A
Published: October 2023

Nickel-based oxides are selected for their inexpensive cost, well-defined redox activity, and flexibility in adjusting nanostructures via optimization of the synthesis process. This communique explores the field of energy storage for hydrothermally synthesized NiO/ZnO nanowires by analysing their capacitive behaviour. The p-type NiO was successfully built onto the well-ordered mesoporous n-type ZnO matrix, resulting in the formation of p–n heterojunction artefacts with porous nanowire architectures. NiO/ZnO nanowire-based electrodes exhibited much higher electrochemical characteristics than bare NiO nanowires. The heterojunction at the interface between the NiO and ZnO nanoparticles, their specific surface area, as well as their combined synergetic influence, are accountable for the high specific capacitance (C
s) of 1135 Fg−1 at a scan rate of 5 mV s−1. NiO/ZnO nanowires show an 18% dip in initial capacitance even after 6000 cycles, indicating excellent capacitance retention and low resistance validated by electrochemical impedance spectroscopy. In addition, the specific capacitance, energy and power density of the solid state asymmetric capacitor that was manufactured by employing NiO/ZnO as the positive electrode and activated carbon as the negative electrode were found to be 87 Fg−1, 23 Whkg−1 and 614 Wkg−1, respectively. The novel electrode based on NiO/ZnO demonstrates excellent electrochemical characteristics all of which point to its promising application in supercapacitor devices.
Bibliometric analysis of aptamer-conjugated nanoparticles for diagnosis in the last two decades
Authors: Liu Mao-Sheng , Zhong Si-Si , Jiang Song , Wang Ting , Zhang Kun-He
Published: October 2023

Objective. Aptamer-conjugated nanoparticles for diagnosis have recently gained increasing attention. Here, we performed a bibliometric analysis to provide an overview of this field over the past two decades. Methods. The terms ‘aptamer, nanoparticles and diagnosis’ were used to search for relevant original articles published in English from 2003 to 2022 in the Web of Science database. VOSviewer and CiteSpace software were employed to analyze the development process, knowledge structure, research hotspots, and potential trends in the field of aptamer-conjugated nanoparticles for diagnosis. Results. A total of 1076 original articles were retrieved, with a rapid increase in the annual output and citation. The journal ‘Biosensors and Bioelectronics’ has contributed the most in this field, and the most influential researcher, institution and country were Weihong Tan, the Chinese Academy of Sciences, China, respectively. Gold nanoparticles and quantum dots were the most used, but in the past three years, research hotspots focused on carbon dots and graphene quantum dots. Diagnostic directions primarily focused on cancer. The most used strategy was label-free electrochemical detection, but in the past two years, colorimetric analysis and fluorescence imaging emerged as hot topics. Conclusion. The bibliometric analysis reveals a rapid increase in the research on aptamer-conjugated nanoparticles for diagnosis, major contributors at the levels of journals, authors, institutions, and countries, and research preferences in diagnostic objects, nanoparticle types, and detection methods, as well as the evolution of research hotspots and future trends.
Ultrafast and ultrastable FeSe2 embedded in nitrogen-doped carbon nanofibers anode for sodium-ion half/full batteries
Authors: Chen Chen , Hu Qilin , Xue Hongyu , Li Han , Li Wenkai , Cao Shuai , Peng Tao , Yang Ya , Luo Yongsong
Published: October 2023

Transition metal selenides are considered as promising anode materials for fast-charging sodium-ion batteries due to their high theoretical specific capacity. However, the low intrinsic conductivity, particle aggregation, and large volume expansion problems can severely inhibit the high-rate and long-cycle performance of the electrode. Herein, FeSe2 nanoparticles embedded in nitrogen-doped carbon nanofibers (FeSe2@NCF) have been synthesized using the electrospinning and selenization process, which can alleviate the volume expansion and particle aggregation during the sodiation/desodiation and improve the electrical conductivity of the electrode. The FeSe2@NCF electrode delivers the outstanding specific capacity of 222.3 mAh g−1 at a fast current density of 50 A g−1 and 262.1 mAh g−1 at 10 A g−1 with the 87.8% capacity retention after 5000 cycles. Furthermore, the Na-ion full cells assembled with pre-sodiated FeSe2@NCF as anode and Na3V2(PO4)3/C as cathode exhibit the reversible specific capacity of 117.6 mAh g−1 at 5 A g−1 with the 84.3% capacity retention after 1000 cycles. This work provides a promising way for the conversion-based metal selenides for the applications as fast-charging sodium-ion battery anode.
An efficient robotic-assisted bolt-ball joint looseness monitoring approach using CBAM-enhanced lightweight ResNet
Authors: Li Li , Yuan Rui , Lv Yong , Xu Shijie , Hu Huangxing , Song Gangbing
Published: October 2023

Bolt-ball joints are widely used in space structures, and their looseness may lead to major safety accidents. The current bolt monitoring methods based on deep learning usually have high computational complexity, and it is difficult to guarantee its computational efficiency under practical scenario. To mitigate this problem, here in this paper, an efficient robotic-assisted bolt-ball joint looseness monitoring approach using convolutional block attention module (CBAM)-enhanced lightweight ResNet is proposed. Firstly, the robotic-assisted tapping method is applied to bolt-ball joints to generate audio signals, which are constructed into time-frequency maps by continuous wavelet transform. Secondly, the original ResNet is improved as a lightweight network, which successfully reduces model complexity, and employs time-frequency maps as input. Then, CBAM is introduced to capture global information and focus on the critical feature. Thus, the efficiency of feature extraction is significantly improved. Finally, by the overall optimized structure, a CBAM-enhanced lightweight ResNet model is established to monitor the bolt-ball joints looseness state accurately. Experimental results demonstrate the high efficiency while maintaining very lightweight structure of the proposed method, verifying the effectiveness and superiority of the robot-assisted approach using CBAM-enhanced lightweight ResNet over other methods.
The Josephson junction as a quantum engine
Authors: Alicki Robert , Horodecki Michał , Jenkins Alejandro , Łobejko Marcin , Suárez Gerardo
Published: October 2023

We treat the Cooper pairs in the superconducting electrodes of a Josephson junction (JJ) as an open system, coupled via Andreev scattering to external baths of electrons. The disequilibrium between the baths generates the direct-current bias applied to the JJ. In the weak-coupling limit we obtain a Markovian master equation that provides a simple dynamical description consistent with the main features of the JJ, including the form of the current–voltage characteristic, its hysteresis, and the appearance under periodic voltage driving of discrete Shapiro steps. For small dissipation, our model also exhibits a self-oscillation of the JJ’s electrical dipole with frequency

Ω
=
2
e
V

/

ℏ

around mean voltage V. This self-oscillation, associated with ‘hidden attractors’ of the nonlinear equations of motion, explains the observed production of monochromatic radiation with frequency Ω and its harmonics. We argue that this picture of the JJ as a quantum engine resolves open questions about the Josephson effect as an irreversible process and could open new perspectives in quantum thermodynamics and in the theory of dynamical systems.
Comparison of confidence regions for quantum state tomography
Authors: Almeida Jessica O de , Kleinmann Matthias , Sentís Gael
Published: October 2023

The quantum state associated to an unknown experimental preparation procedure can be determined by performing quantum state tomography. If the statistical uncertainty in the data dominates over other experimental errors, then a tomographic reconstruction procedure must express this uncertainty. A rigorous way to accomplish this is via statistical confidence regions (CRs) in state space. Naturally, the size of this region decreases when increasing the number of samples, but it also depends critically on the construction method of the region. We compare recent methods for constructing CRs as well as a reference method based on a Gaussian approximation. For the comparison, we propose an operational measure with the finding, that there is a significant difference between methods, but which method is preferable can depend on the details of the state preparation scenario.
Optimal resetting strategies for search processes in heterogeneous environments
Authors: García-Valladares Gregorio , Plata Carlos A , Prados Antonio , Manacorda Alessandro
Published: October 2023

In many physical situations, there appears the problem of reaching a single target that is spatially distributed. Here we analyse how stochastic resetting, also spatially distributed, can be used to improve the search process when the target location is quenched, i.e. it does not evolve in time. More specifically, we consider a model with minimal but sufficient ingredients that allows us to derive analytical results for the relevant physical quantities, such as the first passage time distribution. We focus on the minimisation of the mean first passage time (MFPT) and its fluctuations (standard deviation), which proves to be non-trivial. Our analysis shows that the no-disorder case is singular: for small disorder, the resetting rate distribution that minimises the MFPT leads to diverging fluctuations—which impinge on the practicality of this minimisation. Interestingly, this issue is healed by minimising the fluctuations: the associated resetting rate distribution gives first passage times that are very close to the optimal ones.
Anisotropic strange stars and its maximum mass in Finch-Skea geometry in dimensions D ≥ 4
Authors: Das B , Goswami K B , Saha A , Chattopadhyay P K
Published: October 2023

In this article, we have demonstrated a stellar model for compact stars in the presence of strange matter embedded in D ≥ 4 dimensional space-time defined by the Finch-Skea metric. To study the relevant physical properties of the interior matter, we consider the equation of state (henceforth
EOS)

p
=

1

3

(
ρ
−
4
B
)

as proposed in the MIT bag model, where B is termed the bag constant. The mass-radius relationship in four and higher dimensions is determined using the range of values of surface density through the relation ρ

s
= 4B, for which bulk strange matter may be a viable issue for compact objects. Here, we choose the range of B so that stable strange matter may exist relative to a neutron at zero external pressure. We note that a maximum value of the stellar radius exists when B is fixed at a given allowed value for which metric functions considered to be real here. This is the maximum allowed radius

(

b

max

)

in this model, which depends on the surface density of a strange star. In four dimensions, the compactness of a star is found to be greater than 0.33. In the case of higher dimensions (D > 4), we observed different values of compactness. Causality conditions are satisfied interior to the star up to the maximum allowed radius

(

b

max

)

, for which the metric function is real. The validity of the energy conditions, surface redshift and other parameters of the stellar configuration are studied, and new results are found. The stability of the model is also studied.
The spatial wavefunction of half-integer spins
Authors: van Veenendaal Michel
Published: October 2023

Within a nonrelativistic framework, spin is generally included as an intrinsic angular momentum. It is proposed here that consistent results can be obtained with a spatial wavefunction of an oriented complex exponential

e

∓
i

a

ˆ

φ

, where the bivector

i

a

ˆ

is written in terms of the pseudoscalar
i
= e

x

e

y

e

z
and the axis of rotation given by the unit vector

a

ˆ

, which is generally an (effective) magnetic field direction (this can also be written as

e

∓
i
σ
·

a

ˆ

φ

in terms of the Pauli vector
σ
). The wavefunction is a multivector and not a complex scalar. The signs in the exponential correspond to the two directions of rotation around the axis. The transformation properties of these wavefunctions are given by the Pauli spinors. Spin can be viewed as a zero-point rotation arising from the noncommutativity of the momentum and the vector potential.
Dynamics of the modified emden and pseudo-modified emden equations: position-dependent mass, invariance and exact solvability
Authors: Mustafa Omar
Published: October 2023

We consider the modified Emden equation (MEE) and introduce its most general solution, using the most general solution for the simple harmonic oscillator’s linear dynamical equation (i.e. the initial conditions shall be identified by the PDM-MEE problem at hand). We use a general nonlocal point transformation and show that modified Emden dynamical equation is transformed to describe position-dependent mass (PDM) classical particles. Two PDM-MEE-type classical particles are used as illustrative examples, and their exact solutions are reported. Under specific parametric considerations, the phase-space trajectories are reported for the MEE-type and for PDM-MEE-type classical particles.