bluuebunny/crossref_metadata_2025 huggingface dataset:
Limit cycles and homoclinic networks in two-dimensional polynomial systems
Authors: Luo Albert C. J.
Published: February 2024

In this paper, the properties of equilibriums in planar polynomial dynamical systems are studied. The homoclinic networks of sources, sinks, and saddles in self-univariate polynomial systems are discussed, and the numbers of sources, sinks, and saddles are determined through a theorem, and the first integral manifolds are determined. The corresponding proof of the theorem is completed, and a few illustrations of networks for source, sinks, and saddles are presented for a better understanding of the homoclinic networks. Such homoclinic networks are without any centers even if the networks are separated by the homoclinic orbits. The homoclinic networks of positive and negative saddles with clockwise and counterclockwise limit cycles in crossing-univariate polynomial systems are studied secondly, and the numbers of saddles and centers are determined through a theorem, and the first integral manifolds are determined through polynomial functions. The corresponding proof of the theorem is given, and a few illustrations of networks of saddles and centers are given to show the corresponding geometric structures. Such homoclinic networks of saddles and centers are without any sources and sinks. Since the maximum equilibriums for such two types of planar polynomial systems with the same degrees are discussed, the maximum centers and saddles should be obtained, and maximum sinks, sources, and saddles should be achieved. This paper may provide a different way to determine limit cycles in the Hilbert 16th problem.
Interplay between protonation and Jahn–Teller effects in a manganese vanadium cubane water oxidation catalyst
Authors: Tippner Simon , Lechner Patrick , González Leticia , Mai Sebastian
Published: February 2024

Understanding the protonation behavior of metal-oxo water oxidation catalysts is essential to improve catalyst efficiency and long-term performance, as well as to tune their properties for specific applications. In this work, we explore the basicity and protonation effects of the highly active water oxidation catalyst [(Mn4O4) (V4O13) (OAc)3]3− using density functional theory. We computed the relative free energies of protonation in a systematic fashion for all symmetry-inequivalent O atoms, where the presence of multiple oxidation states from Mn4IV to Mn4III and a rich Jahn–Teller isomerism adds a significant amount of complexity. For high oxidation states, the compound behaves like some other polyoxometalates, showing protonation preferably at the terminal and μ2-bridging O atoms of the vanadate cap. However, upon reduction, eventually, the protonation preference switches to the cubane O atoms, mostly driven by a strong increase in basicity for O atoms located along the Jahn–Teller axes. Our work further evidences that protonation can potentially lead to several chemical transformations, like disproportionation and charge transfer to vanadium, dissociation of ligands, or the opening of the cubane structure. Our simulated UV/Vis absorption spectra additionally provide valuable insights about how the protonation of the catalyst could be tracked experimentally. Overall, our analysis highlights the complexity involved in the protonation of heterometallic polyoxometalate clusters.
Quantum-classical rate coefficient datasets of vibrational energy transfer in carbon monoxide based on highly accurate potential energy surface
Authors: Hong Qizhen , Storchi Loriano , Coletti Cecilia , Li Jia , Sun Quanhua , Li Jun
Published: February 2024

A merged potential energy surface (PES) is introduced for CO + CO collisions by combining a recent full-dimensional ab initio PES [Chen et al. J. Chem. Phys. 153, 054310 (2020)] and analytical long-range multipolar interactions. This merged PES offers a double advantage: it retains the precision of the ab initio PES in describing the van der Waals well and repulsive short range while providing an accurate physical description of long-range interaction; it significantly reduces the computational time required for trajectory integration since the long-range portion of the ab initio PES (involving numerous neural network fitting parameters) is now replaced by the analytical model potential. Based on the present merged PES, mixed Quantum-Classical (MQC) calculations, which capture quantum effects related to vibrational motion, align with a range of experimental data, including transport properties, vibrational energy transfer between CO and its isotoplogues, as well as rate coefficients for V–V and V–T/R processes. Notably, the original ab initio PES yields V–T/R rate coefficients at low temperatures that are significantly higher than the experimental data due to the artificial contribution of its unphysical long-range potential. In addition to conducting extensive MQC calculations to obtain raw data for V–V and V–T/R rate coefficients, we employ Gaussian process regression to predict processes lacking computed MQC data, thereby completing the considered V–V and V–T/R datasets. These extensive rate coefficient datasets, particularly for V–T/R processes, are unprecedented and reveal the significant role played by V–T/R processes at high temperatures, emphasizing the necessity of incorporating both V–V and V–T/R processes in the applications.
Intrinsic magnetism in KTaO3 heterostructures
Authors: Krantz Patrick W. , Tyner Alexander , Goswami Pallab , Chandrasekhar Venkat
Published: February 2024

There has been intense recent interest in the two-dimensional electron gases (2DEGs) that form at the surfaces and interfaces of KTaO3 (KTO), with the discovery of superconductivity at temperatures significantly higher than those of similar 2DEGs based on SrTiO3 (STO). Like STO heterostructures, these KTO 2DEGs are formed by depositing an overlayer on top of appropriately prepared KTO surfaces. Some of these overlayers are magnetic, and the resulting 2DEGs show signatures of this magnetism, including hysteresis in the magnetoresistance (MR). Here, we show that KTO 2DEGs fabricated by depositing AlOx on top of KTO also show hysteretic MR, indicative of long-range magnetic order, even though the samples nominally contain no intrinsic magnetic elements. The hysteresis appears in both the transverse and longitudinal resistance in magnetic fields both perpendicular to and in the plane of the 2DEG. The hysteretic MR has different characteristic fields and shapes for surfaces of different crystal orientations and vanishes above a few Kelvin. Density functional theory (DFT) calculations indicate that the magnetism likely arises from Ta4+ local moments created in the presence of oxygen vacancies.
Fluid modeling of CF3I/CO2 arc formation process
Authors: Peng Shidong , Li Jing , Yin Yue , Jian Wen , Fu Si , Liu Shuxin , Cao Yundong , Lu Jiaxin
Published: February 2024

The environmentally friendly insulating gas CF3I is a promising replacement for SF6 due to its excellent insulation and arc extinguishing performance. In the arc chamber of high-voltage circuit breakers filled with CF3I/CO2, the near-electrode sheath dominates the current transfer process between contact and arc column during arc formation, which has a significant effect on the transition from glow to arc discharge. The 30%CF3I/70%CO2 was taken as the research object in this research, and a more perfect fluid model was established considering the influence of diffusion current. The arc formation process between the contacts at the preliminary stage of circuit breaker interruption was conducted. The results show that the arc formation process can be divided into three stages: glow discharge, abnormal glow discharge, and arc discharge. As the arc formation process proceeds, the thickness of the near-cathode sheath decreases gradually. When the arc reaches stability with the current density 8×106–1.6×107A·m−2, the thickness of the near-cathode sheath is 7 μm, the steep voltage fall near the cathode sheath is generated within 7 μm away from the cathode surface, and this voltage fall almost does not change with the current density. CF3I− is the dominant negative ion between the contacts, which indicates that CF3I has excellent electron adsorption performance and is beneficial to arc deionization. The computational results of this work were compared with the existing experimental ones, which shows that the model used in this work is accurate enough. Finally, suggestions for model optimization and future work are given.
Absorption dispersion below boson peak frequency in oxide glasses studied by THz-time domain spectroscopy
Authors: Wada Osamu , Ramachari Doddoji , Yang Chan-Shan , Uchino Takashi , Pan Ci-Ling
Published: February 2024

The dispersion properties of the absorption coefficients [α(ν)] of different multi-component silicate oxide glasses have been studied in the frequency region below the boson peak by using THz-time-domain spectroscopy. The value of α(ν)/ν2 has been shown to exhibit a minimum level (R) at low frequency and subsequently a linear increase in the form of r(ν/νBP + E) with increasing frequency, where νBP is the boson peak frequency and R, r, and E are material-specific constants. It has also been found that R ∝ r and E is a constant common to most glasses. This α(ν)/ν2 behavior is ascribed to the dispersion property of the light-vibration coupling coefficient under the reasonable vibrational density of state function. The minimum (constant) and linear terms of the α(ν)/ν2 spectrum are originated from the physical/chemical disorder-induced charge fluctuations in the long-range scale (constant term) and short-range scale (linear term), respectively. The fluctuating charge (σ1) caused by uncorrelated, long-range disorders has primary significance for determining the sub-THz absorption dispersion properties, and its value has been determined for each glass material.
Bidirectional prediction between wake velocity and surface pressure using deep learning techniques
Authors: Liu Junle , Shum Kihing , Tse Tim K. T. , Hu Gang
Published: February 2024

The surface pressure and flow field of rectangular cylinders are of great importance in aerodynamic analyses of the cylinders. In general, it is easy to obtain one side of the information, either the surface pressure or the flow field, in reality. Deep learning (DL) techniques provide a new perspective to infer one side of the information from the other. Novel DL algorithms, specifically Dense Neuron Networks (DNN) and Graphic Attention Networks (GAT), are incorporated into the proposed high accuracy bidirectional prediction models in order to tackle the practical problems above. DNN employs a sequential compression architecture with a residual connection, and GAT applies an attention mechanism to update node value by connection edges defined by the relative position. The results demonstrate that in predicting surface pressure using wake velocity, GAT exhibits a 50% lower mean square error and more stable training progress than the DNN model. Predicting wake velocity using surface pressure yields accurate results for both DNN and GAT models. Specifically, the GAT structure shows better performance in capturing the vortex information near the trailing edge of the cylinder. Comparison of two models suggests that the GAT capability of rationally defining the interconnection of nodes through edges is advantageous in solving flow problems involving a spatially generalized physical mechanism.
Hydrogen bonding in glassy trehalose–water system: Insights from density functional theory and molecular dynamics simulations
Authors: Kocherbitov Vitaly , Music Denis , Veryazov Valera
Published: February 2024

We report a detailed density functional theory and molecular dynamics study of hydrogen bonding between trehalose and water, with a special emphasis on interactions in the amorphous solid state. For comparison, water–water interactions in water dimers and tetramers are evaluated using quantum calculations. The results show that the hydrogen bonding energy is dependent not only on the geometry (bond length and angle) but also on the local environment of the hydrogen bond. This is seen in quantum calculations of complexes in vacuum as well as in amorphous solid states with periodic boundary conditions. The temperature-induced glass transition in the trehalose–water system was studied using molecular dynamics simulations with varying cooling and heating rates. The obtained parameters of the glass transition are in good agreement with the experiments. Moreover, the dehydration of trehalose in the glassy state was investigated through a gradual dehydration with multiple small steps under isothermal conditions. From these simulations, the values of water sorption energy at different temperatures were obtained. The partial molar enthalpy of mixing of water value of −18 kJ/mol found in calorimetric experiments was accurately reproduced in these simulations. These findings are discussed in light of the hydrogen bonding data in the system. We conclude that the observed exothermic effect is due to different responses of liquid and glassy matrices to perturbations associated with the addition or removal of water molecules.
The nonlinear wave dynamics of the space-time fractional van der Waals equation via three analytical methods
Authors: Altalbe Ali , Zaagan Abdullah A. , Bekir Ahmet , Cevikel Adem
Published: February 2024

In this paper, we explore the new exact soliton solutions of the truncated M-fractional nonlinear (1 + 1)-dimensional van der Waals equation by applying the  expa function method, extended (G′/G)-expansion method, and modified simplest equation method. The concerned equation is a challenging problem in the modeling of molecules and materials. Noncovalent van der Waals or dispersion forces are frequent and have an impact on the structure, dynamics, stability, and function of molecules and materials in biology, chemistry, materials science, and physics. The results obtained are verified and represented by two-dimensional, three-dimensional, and contour graphs. These results are newer than the existing results in the literature due to the use of fractional derivative. The achieved solutions will be of high significance in the interaction of quantum-mechanical fluctuations, granular matter, and other areas of van der Waals equation applications. Therefore, the obtained solutions are valuable for future studies of this model.
Diffusiophoresis of charge-regulated nanoparticles comprising finite ion size and electrostatic correlation effects
Authors: Mondal Bapan , Bhattacharyya Somnath
Published: February 2024

Diffusiophoresis of nanoparticles is studied based on a modified electrokinetic model accounting the electrostatic correlation of finite sized ions and their non-electrostatic steric interactions. Hydrated ions are modeled as charged hard spheres suspended in the medium, which creates a volume exclusion due to ion–ion steric interactions and the medium viscosity to vary with the ionic volume fraction. The surface charge of the particle is considered to depend on the pH and concentration of electrolyte. We have adopted the Carnahan–Starling equation of state to model the ion steric interactions. The electrostatic correlation is incorporated by minimizing the free energy, which leads to a fourth-order modified Poisson equation for the electric field with the correlation length depending on the bulk ionic concentration, surface charge, and valence of the counterions. Due to the consideration of the ion–ion correlation, the effective screening length of the surface charge expands as the ionic concentration as well as valence of counterions is increased. The counterion saturation created by the ion steric interaction attenuates the screening of the surface charge. In addition, the ion steric interaction augments the diffusion field. Thus, the modified electrokinetic model shows a significant deviation from the standard Poisson–Nernst–Planck model. Governing equations in their full form are solved numerically through a control volume approach. A simplified model based on a linear perturbation analysis is also developed. We have considered multivalent electrolytes and demonstrated the overscreening of the surface charge and an oscillation in the charge density distribution. Through this study, we have elucidated the impact of several non-linear electrostatic phenomenon such as charge regulation, ion steric interactions, and ion–ion correlations, which has not been addressed in the context of diffusiophoresis.
Dual-phase model: Estimating the temperature and hydrodynamic size of magnetic nanoparticles with protein-corona formation
Authors: Liu Jingxin , Zhang Zhihui , Xie Qingguo , Liu Wenzhong
Published: February 2024

The use of magnetic nanothermometry faces challenges in noninvasive thermal monitoring during hyperthermia therapy due to the impact of the biological protein corona. Herein, we present an advanced magnetic nanothermometry model that incorporates the linear and cubic susceptibility phases, ensures robustness against hydrodynamic variations, maintains concentration independence, and can adapt to diverse magnetic field intensities. In this work, we studied five types of particles with comparable core structures (single- and multi-core) and chemical compositions (carboxyl and plain) before and after incubation with bovine serum albumin. Temperature-measurement experiments were conducted spanning both room temperature and a physiological temperature range of 10 K. The results highlight the model's effectiveness, especially for single-core particles exhibiting Brownian relaxation behavior, with temperature errors controlled to within ±0.4 K. The model's predictions remained consistent irrespective of particle chemical compositions, while detecting hydrodynamic diameter changes post-incubation, indirectly highlighting protein–corona interactions. These findings enhance the application potential of magnetic nanothermometry in hyperthermia therapy, contributing to preclinical validations and insights into nanoparticle–biological interactions.
Confusion cannot explain cooperative behavior in public goods games
Authors: Wang Guangrong , Li Jianbiao , Wang Wenhua , Niu Xiaofei , Wang Yue
Published: February 2024

Some scholars find that behavioral variation in the public goods game is explained by variations in participants’ understanding of how to maximize payoff and that confusion leads to cooperation. Their findings lead them to question the common assumption in behavioral economics experiments that choices reflect motivations. We conduct two experiments, in which we minimize confusion by providing participants with increased training. We also introduce a question that specifically assesses participants’ understanding of payoff maximization choices. Our experimental results show that the distribution of behavior types is significantly different when participants play with computers versus humans. A significant increase in contributions is also observed when participants play with humans compared to when they play with computers. Moreover, social norms may be the main motive for contributions when playing with computers. Our findings suggest that social preferences, rather than confusion, play a crucial role in determining contributions in public goods games when playing with humans. We therefore argue that the assumption in behavioral economics experiments that choices reveal motivations is indeed valid.
Real-time imaging of standing-wave patterns in microresonators
Authors: Yan Haochen , Ghosh Alekhya , Pal Arghadeep , Zhang Hao , Bi Toby , Ghalanos George , Zhang Shuangyou , Hill Lewis , Zhang Yaojing , Zhuang Yongyong , Xavier Jolly , Del’Haye Pascal
Published: February 2024

Real-time characterization of microresonator dynamics is important for many applications. In particular, it is critical for near-field sensing and understanding light–matter interactions. Here, we report camera-facilitated imaging and analysis of standing wave patterns in optical ring resonators. The standing wave pattern is generated through bidirectional pumping of a microresonator, and the scattered light from the microresonator is collected by a short-wave infrared (SWIR) camera. The recorded scattering patterns are wavelength dependent, and the scattered intensity exhibits a linear relation with the circulating power within the microresonator. By modulating the relative phase between the two pump waves, we can control the generated standing waves’ movements and characterize the resonator with the SWIR camera. The visualized standing wave enables subwavelength distance measurements of scattering targets with nanometer-level accuracy. This work opens broad avenues for applications in on-chip near-field (bio)sensing, real-time characterization of photonic integrated circuits, and backscattering control in telecom systems.
Optimizing non-Newtonian fluids for impact protection of laminates
Authors: Richards James A. , Hodgson Daniel J. M. , O’Neill Rory E. , DeRosa Michael E. , Poon Wilson C. K.
Published: February 2024

Non-Newtonian fluids can be used for the protection of flexible laminates. Understanding the coupling between the flow of the protecting fluid and the deformation of the protected solids is necessary in order to optimize this functionality. We present a scaling analysis of the problem based on a single coupling variable, the effective width of a squeeze flow between flat rigid plates, and predict that impact protection for laminates is optimized by using shear-thinning, and not shear-thickening, fluids. The prediction is verified experimentally by measuring the velocity and pressure in impact experiments. Our scaling analysis should be generically applicable for non-Newtonian fluid–solid interactions in diverse applications.
Second language processing of English definite noun phrases by Spanish speakers and Japanese speakers
Authors: Snape Neal , Hosoi Hironobu , Umeda Mari
Published: February 2024

The present study examines the acquisition of definite noun phrases (NPs) in L2 English. Both English and Spanish
have a definite article, but Japanese lacks articles, though definite anaphoric and definite non-anaphoric are present to some
degree through the optional use of sono (the/that). A self-paced reading task was administered to assess
real-time processing in the comprehension of different types of definite NPs by L2-English learners. The self-paced reading
results show processing of definite NPs is influenced by proficiency level rather than L1 transfer effects. We discuss our
findings in reference to the Morphological Congruency Hypothesis and the Lexical Learning/Lexical Transfer model and suggest that
our data support the latter but not the former.
E-cadherin loss drives diffuse-type gastric tumorigenesis via EZH2-mediated reprogramming
Authors: Zou Gengyi , Huang Yuanjian , Zhang Shengzhe , Ko Kyung-Pil , Kim Bongjun , Zhang Jie , Venkatesan Vishwa , Pizzi Melissa P. , Fan Yibo , Jun Sohee , Niu Na , Wang Huamin , Song Shumei , Ajani Jaffer A. , Park Jae-Il
Published: February 2024

Diffuse-type gastric adenocarcinoma (DGAC) is a deadly cancer often diagnosed late and resistant to treatment. While hereditary DGAC is linked to CDH1 mutations, the role of CDH1/E-cadherin inactivation in sporadic DGAC tumorigenesis remains elusive. We discovered CDH1 inactivation in a subset of DGAC patient tumors. Analyzing single-cell transcriptomes in malignant ascites, we identified two DGAC subtypes: DGAC1 (CDH1 loss) and DGAC2 (lacking immune response). DGAC1 displayed distinct molecular signatures, activated DGAC-related pathways, and an abundance of exhausted T cells in ascites. Genetically engineered murine gastric organoids showed that Cdh1 knock-out (KO), KrasG12D, Trp53 KO (EKP) accelerates tumorigenesis with immune evasion compared with KrasG12D, Trp53 KO (KP). We also identified EZH2 as a key mediator promoting CDH1 loss-associated DGAC tumorigenesis. These findings highlight DGAC’s molecular diversity and potential for personalized treatment in CDH1-inactivated patients.
Stability estimate for an inverse stochastic parabolic problem of determining unknown time-varying boundary
*
Authors: Liao Zhonghua , Lü Qi
Published: February 2024

Stochastic parabolic equations are widely used to model many random phenomena in natural sciences, such as the temperature distribution in a noisy medium, the dynamics of a chemical reaction in a noisy environment, or the evolution of the density of bacteria population. In many cases, the equation may involve an unknown moving boundary which could represent a change of phase, a reaction front, or an unknown population. In this paper, we focus on an inverse problem with the goal is to determine an unknown moving boundary based on data observed in a specific interior subdomain for the stochastic parabolic equation. The uniqueness of the solution of this problem is proved, and furthermore a stability estimate of log type is derived. This allows us, theoretically, to track and to monitor the behavior of the unknown boundary from observation in an arbitrary interior domain. The primary tool is a new Carleman estimate for stochastic parabolic equations. As a byproduct, we obtain a quantitative unique continuation property for stochastic parabolic equations.
Production and protection of entanglement via vacuum induced coherences
Authors: Nair Anjali N , Arun R
Published: February 2024

The entanglement dynamics of a pair of three-level V-type atoms decaying spontaneously in a common vacuum reservoir is investigated. Under the condition that the decaying transitions in the atoms have parallel dipole moments, the effect of coherences induced by spontaneous emission is considered in the atomic dynamics. We show that vacuum-induced coherence (VIC) and collective effects in atomic decay play a significant role in the creation of entanglement. By using negativity as a measure of entanglement, we study the time evolution of entanglement for initial separable and generalized Dicke states as well as maximally entangled qutrit states. We show that the effects of VIC enhance the production of entanglement from initial separable states of the atoms. We also show that the entanglement can be protected in steady-state for atoms evolving from initial entangled states. The amount of entanglement that can be preserved is more in the presence of VIC than in its absence.
Ag, Pb co-doped SnSe high performance thermoelectric materials
Authors: Li Shuailing , Li Zhen , Duan Jie , Lou Shiyun , Zhou Shaomin
Published: February 2024

SnSe, as a novel thermoelectric material, has ultrahigh thermoelectric properties in its single crystals, while the thermoelectric properties of polycrystals need to be further improved. Introducing atomic disorder to increase the lattice anharmonicity of the material is a typical strategy to reduce the lattice thermal conductivity and enhance the thermoelectric properties. Ag and Pb co-doping increased the effective carrier mass of the samples, and the resultant strong phonon scattering leads to a drastic decrease of the lattice thermal conductivity over the whole temperature range, and at the same time, optimizes the energy-band structure of SnSe, which finally significantly increases the Seebeck coefficient of SnSe. However, the electrical properties of SnSe deteriorate due to Pb elemental doping, so we introduce Ag atoms with higher intrinsic conductivity to increase its conductivity. At 800 K, the electrical conductivity of the Sn0.82Ag0.08Pb0.1Se sample is about twice as much as that of the undoped SnSe, and the thermal conductivity is 0.28 W mK−1. The ZT value of Sn0.82Ag0.08Pb0.1Se sample peaked at ∼1.33 at 800 K compared to only ∼0.48 for undoped SnSe. The ZT
ave value of Sn0.82Ag0.08Pb0.1Se sample in the temperature range of 300–500 K was ∼0.36 compared to only ∼0.083 for undoped SnSe samples.
Bio-inspired pulsed power switch under shock wave
Authors: Luo Kang , Li Lee , Guo Jingrun , Zhang Lixiong , Hou Tianyu , Shen Hao , Yu Bin , Yang Kai
Published: February 2024

The spark gap switch is a crucial component in the primary energy drive system for large pulse power devices. The switch electrodes are composed of high-density artificial graphite, possessing excellent erosion resistance. However, insufficient mechanical strength in the graphite electrodes makes them especially susceptible to mechanical damage under the enormous impact force caused by the increasing arc current, which seriously affects the reliability and service life of the switch. The distribution of the shock wave overpressure on the graphite electrode surface is deduced and calculated, and the refraction and reflection process of the shock wave from the air to the graphite interface is analyzed based on the Huygens–Fresnel principle. Furthermore, the doubling of refracted shock wave intensity into the graphite electrode is a preliminary characterization. The propagation process of stress wave after the shock wave enters the electrode is investigated by establishing two conventional graphite electrode structure models, namely T-shape and reverse T-shape, which reveal that severe stress concentration occurs in both structures. Drawing inspiration from the physiological structure of the woodpecker’s head, renowned for its exceptional impact resistance, the macroscopic geometry of the graphite electrode and the assembly structure of the switch have been bionically designed. The simulation results demonstrate that, in comparison to the conventional electrode structure, the bionic electrode structure eliminates stress concentration at the bolt end and electrode corner, while significantly reducing maximum equivalent stress and the degree of the stress concentration on the bottom surface of the electrode. These features contribute to the enhancement of the current capacity and reliability of the spark gap switch.
Metal oxide-mixed polymer-based hybrid electrochromic supercapacitor: improved efficiency and dual band switching
Authors: Sahu Bhumika , Bansal Love , Ghosh Tanushree , Kandpal Suchita , Rath Deb Kumar , Rani Chanchal , Wesemann Christoph , Bigall Nadja C , Kumar Rajesh
Published: February 2024

The inclusion of charge storage properties in electrochromic devices (ECDs) has gained much interest and has evolved into a promising emerging energy-related field due to multifunctional smart device applications. Here, an organic–inorganic solid-state asymmetric electrochromic supercapacitor device (ESCD) containing nano-CoTiO3-mixed poly-3-hexylthiophene and WO3 as two electrodes has been designed to study electrochromic and supercapacitor properties. The electrochemical properties of CoTiO3 show a pseudocapacitive-type charge storage capability, which has been utilized to enhance the electrochromic performance of the ESCD with additional charge storage ability. The device shows charge storage properties with fast charging and slow discharging, giving very high coulombic efficiency with a specific capacitance of 6.4 mF cm−2 at 0.2 mA cm−2 current density. The device shows excellent electrochromic supercapacitive properties with a color contrast of ∼50% and a short switching time of ∼1 s at a 515 nm wavelength with excellent cyclic stability. The device exhibits the capability to cut near infrared wavelength (700 nm and 850 nm) and has a potential application as a heat filtering device. Thus, the addition of pseudocapacitive-type materials in ECDs enhances the capacitive performance along with electrochromic properties, which makes ECDs more suitable for real life applications.
B
0—
B¯0
mixing in the U(1)
X
SSM
Authors: Han Xing-Yu , Zhao Shu-Min , Wang Xi , Wang Yi-Tong , Wang Tong-Tong , Long Xin-Xin , Dong Xing-Xing , Feng Tai-Fu
Published: February 2024

U(1)
X
SSM is a non-universal Abelian extension of the Minimal Supersymmetric Standard Model and its local gauge group is extended to SU(3)
C
× SU(2)
L
× U(1)
Y
× U(1)
X
. Based on the latest data of neutral meson mixing and experimental limitations, we investigate the process of

B

0

−

B

0

¯

mixing in U(1)
X
SSM. Using the effective Hamiltonian method, the Wilson coefficients and mass difference Δm

B
are derived. The abundant numerical results verify that

v

S

,

M

D

2

,

λ

C

,

μ
,

M

2

,

tan
β
,

g

YX

,

M

1

and λ

H
are sensitive parameters to the process of

B

0

−

B

0

¯

mixing. With further measurement in the experiment, the parameter space of the U(1)
X
SSM will be further constrained during the mixing process of

B

0

−

B

0

¯

.
Van Hove singularity driven enhancement of superconductivity in two-dimensional tungsten monofluoride (WF)
Authors: Jamwal Prarena , Ahuja Rajeev , Kumar Rakesh
Published: February 2024

Superconductivity in two-dimensional materials has gained significant attention in the last few years. In this work, we report phonon-mediated superconductivity investigations in monolayer Tungsten monofluoride (WF) by solving anisotropic Migdal Eliashberg equations as implemented in EPW. By employing first-principles calculations, our examination of phonon dispersion spectra suggests that WF is dynamically stable. Our results show that WF has weak electron–phonon coupling (EPC) strength (λ) of 0.49 with superconducting transition temperature (T

c
) of 2.6 K. A saddle point is observed at 0.11 eV below the Fermi level (E

F
) of WF, which corresponds to the Van Hove singularity (VHS). On shifting the Fermi level to the VHS by hole doping (3.7 × 1014 cm−2), the EPC strength increases to 0.93, which leads to an increase in the T

c
to 11 K. However, the superconducting transition temperature of both pristine and doped WF increases to approximately 7.2 K and 17.2 K, respectively, by applying the Full Bandwidth (FBW) anisotropic Migdal–Eliashberg equations. Our results provide a platform for the experimental realization of superconductivity in WF and enhancement of the superconducting transition temperature by adjusting the position of E

F
to the VHS.
Outer surface defect detection of steel pipes with 3D vision based on multi-line structured lights
Authors: Jin Lei , Li Siyuan , Qin Guan , Xu Ke
Published: February 2024

Surface defects pose a significant threat to the quality of hot rolled seamless steel pipes. While the efficacy of contemporary vision-based deep learning methodologies is undeniable, they encounter significant challenges in accurately identifying defects of substantial depth that compromise quality. Furthermore, these techniques often erroneously report numerous superficial defects. To overcome this obstacle, we have designed a novel visual detection system specifically for identifying surface defects on steel pipes. This system is inspired by laser triangulation and compensates for the absence of depth information in 2D images by leveraging the shape alterations of a multilinear structured light bar projected onto the steel pipe’s surface. Addressing the challenge of acquiring evenly distributed and difficult-to-obtain defect samples in real-world production processes, we have incorporated an unsupervised anomaly detection network, PatchCore, into the system. The proposed method achieves an area under the receiver operating characteristic curve of 99.84% and an F1 score of 0.9778 on a dataset collected and labeled at an industrial site. Furthermore, the online detection system has been successfully integrated into a hot rolled steel pipe production line, underscoring its practical applicability.
Depth_ASPP_UNet++: a novel 2D ESPI phase unwrapping based on convolutional neural network
Authors: Wang Linlin , Liang Wenjie , Xue Wenke , Zhang Yinwen , Wang Chuanyun , Gao Qian
Published: February 2024

Phase unwrapping is a key step in optical metrology and physical optics to obtain accurate phase distributions. In practice, phase images obtained from electronic speckle pattern interferometry (ESPI) exhibit diverse and complex morphology, with significant shape variations and non-uniform densities among different individuals. This takes challenges for accurately extracting phase information and unwrapping the phase. With the progress of deep learning technology in optical image processing, real-time performance and accuracy have become concerned issues. In this paper, an ESPI phase unwrapping method based on convolutional neural network UNet++ is proposed. The proposed network combines the depthwise separable convolution (DSC), atrous spatial pyramid pooling (ASPP), defined as Depth_ASPP_UNet++. In this model, the use of DSC improves network computational efficiency and provides better feature representation capability. In addition, ASPP is introduced to pay more attention to the phase information of the phase image, and then obtain better phase unwrapping results. The experimental results show that our proposed method can obtain excellent results, especially with various of variable density, different noise levels, and different speckle sizes.
On-shaft ball bearings monitoring by using an inertial measurement unit (IMU): defects severity signatures under stationary and non-stationary conditions
Authors: Chiementin Xavier , Chevallier Eddy , Leroux Solen
Published: February 2024

The present work focuses on the using of an inertial measurement unit (IMU) to monitor the signatures of defects in ball bearings under stationary and non-stationary regimes. The present paper completes the existing literature for both regimes by (i) investigating the influence of IMU parameters on signals derived from six axes and by (ii) proposing signal processing methodologies to detect defects in outer and inner rings. Defects are both declined on the inner and outer rings in five severities, and are studied at six rotation speeds (5 rpm to 400 rpm) and five radial loads (100 kg to 500 kg). Detection and diagnostic were made qualitatively and summarize in tables. Two different methods for processing the non-stationary regime signals are compared. Our results open new ways on the improvement of inertial units and their application.
Applied electric field to repair metal defects and accelerate dehydrogenation
Authors: Gao Yunpeng , Zeng Xiangguo , Chi Minghua
Published: February 2024

Repairing metal micro-defects at the atomic level is very challenging due to their random dispersion and difficulty in identification. At the same time, the interaction of hydrogen with metal may cause hydrogen damage or embrittlement, endangering structural safety. As a result, it is critical to speed up the dehydrogenation of hydrogen-containing materials. The applied electric field can repair the vacancy defects of the material and accelerate the dehydrogenation of the hydrogen-containing metal. The influence of the external environment on the diffusion coefficient of hydrogen in polycrystalline metals was researched using molecular dynamics in this article, and the mechanism of hydrogen diffusion was investigated. Simultaneously, the mechanical characteristics of Fe3Cr alloy were compared during typical heat treatment and electrical treatment. The effect of temperature, electric field strength, and electric field direction on the diffusion coefficient was investigated using orthogonal test analysis. The results demonstrate that temperature and electric field strength have a significant impact on the diffusion coefficient. The atom vibrates violently as the temperature rises, breaking past the diffusion barrier and completing the atomic transition. The addition of the electric field adds extra free energy, decreases the atom’s activation energy, and ultimately enhances the atom’s diffusion coefficient. The repair impact of vacancy defects under electrical treatment is superior to that of typical annealing treatment for polycrystalline Fe3Cr alloy. The electric field can cause the dislocation to migrate, increasing the metal’s toughness and plasticity. This research serves as a useful reference for the electrical treatment of metal materials and offers a method for the quick dehydrogenation of hydrogen-containing materials.
First-principles study on the effect of point defects on the magnetic new mechanism and optical properties of the GaN:Be/Mg/Ca system
Authors: Hou Qingyu , Qi Mude , Li Cong
Published: February 2024

The new magnetic mechanism and optical properties of Ga vacancies and Hi interstitial in the GaN: Be/Mg/Ca system have not been fully understood, and the use of first principles can solve this problem. The effect of point defects on the magnetic mechanism and optical properties of the GaN: Be/Mg/Ca system was investigated using the first nature principle of the hybridized generalized HSE06 method. Results show that all doped systems have N2− ions in addition to N3− ions, and N2− ions have the dual property of itinerant electrons in the off-domain (donor) and of local electrons (acceptor). The magnetism of magnetic doped systems is generated by the hybrid coupling of Ga4s and N2− 2p states. In comparison with the Ga34MN36 (M = Be/Ca) system, the magnetic moments of Ga34MHiN36 (M = Be/Ca) system are reduced after doping with Hi interstitial. The magnetic properties of the Ga34MgN36 system can be regulated by the presence or absence of Hi interstitial, which is advantageous as a magnetic switch. The absorption spectral distribution of the Ga34MgHiN36 system extends to the mid-infrared optical region. This material has some reference value as infrared thermophotovoltaic cells, infrared photodetectors, or infrared semiconductor lasers.
Multileaf collimator characterization and modeling for a 1.5 T MR-linac using static synchronous and asynchronous sweeping gaps
Authors: Kierkels Roel G J , Hernandez Victor , Saez Jordi , Angerud Agnes , Hilgers Guido C , Surmann Kathrin , Schuring Danny , Minken André W H
Published: February 2024

Objective. The Elekta unity MR-linac delivers step-and-shoot intensity modulated radiotherapy plans using a multileaf collimator (MLC) based on the Agility MLC used on conventional Elekta linacs. Currently, details of the physical Unity MLC and the computational model within its treatment planning system (TPS) Monaco are lacking in published literature. Recently, a novel approach to characterize the physical properties of MLCs was introduced using dynamic synchronous and asynchronous sweeping gap (aSG) tests. Our objective was to develop a step-and-shoot version of the dynamic aSG test to characterize the Unity MLC and the computational MLC models in the Monaco and RayStation TPSs. Approach. Dynamic aSG were discretized into a step-and-shoot aSG by investigating the number of segments/sweep and the minimal number of monitor units (MU) per segment. The step-and-shoot aSG tests were compared to the dynamic aSG tests on a conventional linac at a source-to-detector distance of 143.5 cm, mimicking the Unity configuration. the step-and-shoot aSG tests were used to characterize the Unity MLC through measurements and dose calculations in both TPSs. Main results. The step-and-shoot aSGs tests with 100 segments and 5 MU/segment gave results very similar to the dynamic aSG experiments. The effective tongue-and-groove width of the Unity gradually increased up to 1.4 cm from the leaf tip end. The MLC models in RayStation and Monaco agreed with experimental data within 2.0% and 10%, respectively. The largest discrepancies in Monaco were found for aSG tests with >10 mm leaf interdigitation, which are non-typical for clinical plans. Significance. The step-and-shoot aSG tests accurately characterize the MLC in step-and-shoot delivery mode. The MLC model in RayStation 2023B accurately describes the tongue-and-groove and leaf tip effects whereas Monaco overestimates the tongue-and-groove shadowing further away from the leaf tip end.
Ultrasound image segmentation of renal tumors based on UNet++ with fusion of multiscale residuals and dual attention
Authors: Qi Hui , Wang Zhen , Qi Xiaobo , Shi Ying , Xie Tianwu
Published: February 2024

Objective. Laparoscopic renal unit-preserving resection is a routine and effective means of treating renal tumors. Image segmentation is an essential part before tumor resection. The current segmentation method mainly relies on doctors manual delineation, which is time-consuming, labor-intensive, and influenced by their personal experience and ability. And the image quality of segmentation is low, with problems such as blurred edges, unclear size and shape, which are not conducive to clinical diagnosis. Approach. To address these problems, we propose an automated segmentation method, i.e. the UNet++ algorithm fusing multiscale residuals and dual attention (MRDA_UNet++). It replaces two consecutive 3 × 3 convolutions in UNet++ with the ‘MultiRes block’ module, which incorporates coordinate attention to fuse features from different scales and suppress the impact of background noise. Furthermore, an attention gate is also added at the short connections to enhance the ability of the network to extract features from the target area. Main results. The experimental results show that MRDA_UNet++ achieves 93.18%, 92.87%, 93.66%, and 92.09% on the real-world dataset for MIoU, Dice, Precision, and Recall, respectively. Compared to the baseline model UNet++ on three public datasets, the MIoU, Dice, and Recall metrics improved by 6.00%, 7.90% and 18.09% respectively for BUSI, 0.39%, 0.27% and 1.03% for Dataset C, and 1.37%, 1.75% and 1.30% for DDTI. Significance. The proposed MRDA_UNet++ exhibits obvious advantages in feature extraction, which can not only significantly reduce the workload of doctors, but also further decrease the risk of misdiagnosis. It is of great value to assist doctors diagnosis in the clinic.
Effect of interstitial fluid pressure on shear wave elastography: an experimental and computational study
Authors: Cihan Ariana , Holko Kristyna , Wei Luxi , Vos Hendrik J , Debbaut Charlotte , Caenen Annette , Segers Patrick
Published: February 2024

Objective. An elevated interstitial fluid pressure (IFP) can lead to strain-induced stiffening of poroelastic biological tissues. As shear wave elastography (SWE) measures functional tissue stiffness based on the propagation speed of acoustically induced shear waves, the shear wave velocity (SWV) can be used as an indirect measurement of the IFP. The underlying biomechanical principle for this stiffening behavior with pressurization is however not well understood, and we therefore studied how IFP affects SWV through SWE experiments and numerical modeling. Approach. For model set-up and verification, SWE experiments were performed while dynamically modulating IFP in a chicken breast. To identify the confounding factors of the SWV-IFP relationship, we manipulated the material model (linear poroelastic versus porohyperelastic), deformation assumptions (geometric linearity versus nonlinearity), and boundary conditions (constrained versus unconstrained) in a finite element model mimicking the SWE experiments. Main results. The experiments demonstrated a statistically significant positive correlation between the SWV and IFP. The model was able to reproduce a similar SWV-IFP relationship by considering an unconstrained porohyperelastic tissue. Material nonlinearity was identified as the primary factor contributing to this relationship, whereas geometric nonlinearity played a smaller role. The experiments also highlighted the importance of the dynamic nature of the pressurization procedure, as indicated by a different observed SWV-IFP for pressure buildup and relaxation, but its clinical relevance needs to be further investigated. Significance. The developed model provides an adaptable framework for SWE of poroelastic tissues and paves the way towards non-invasive measurements of IFP.