bluuebunny/crossref_metadata_2025 huggingface dataset:
Complications of Percutaneous Irreversible Electroporation for Pancreatic Cancer: A Systematic Review
Authors: Bhatia Harsimran , Maralakunte Muniraju , Gulati Mudita , Sharma Vishal , Gupta Pankaj
Published: February 2025

Objective The aim of the study was to systematically review the percutaneous irreversible electroporation (IRE) complications for pancreatic ductal adenocarcinoma (PDAC).

Methods This systematic review was reported according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines. Two independent reviewers conducted a detailed search in PubMed and EMBASE databases from inception till May 2024. The studies reporting the complications of percutaneous IRE in PDAC using standard scales were included. The primary outcome of interest was the complication rate (including total number of complications and major and minor complications) associated with the percutaneous IRE. IRE-related mortality was also recorded.

Results Of the 2,324 studies, 14 (9 prospective and 3 retrospective) met the inclusion criteria. Of the 748 complications, 114 were major complications (15.2%) and 634 were minor complications (84.7%). The most common complications were abdominal pain (n = 137), diarrhea (n = 57), and nausea and/or vomiting (n = 45). Pancreatitis (n = 57), vascular thrombosis (n = 21), bleeding (n = 21), and biliary complications (n = 26), including bile leaks, cholangitis, and strictures, were other common complications. The overall IRE mortality was 4/584 (0.68%). IRE-related fatal complications included duodenal perforation (n = 2), hepatic artery and superior mesenteric artery thrombosis (n = 1), and purulent peritonitis (n = 1).

Conclusion Although complications are common after IRE for PDAC, most are minor complications. Major complications include bleeding and pancreaticobiliary complications.
The asymptotic infinitesimal distribution of a real Wishart random matrix
Authors: Mingo James A. , Vázquez-Becerra Josué
Published: February 2025

Let XN be a N × N real Wishart random matrix with aspect ratio M/N. The limit eigenvalue distribution of XN is the Marchenko-Pastur law with parameter c = limNM/N. The limit moments {mn}n are given by mn = ∑πc#(π) where the sum runs over NC(n). Let mn′ be the limit of N(E(tr(XNn))−mn). These are the asymptotic infinitesimal moments of a real Wishart matrix. We show that mn′ can be written as a sum over planar diagrams with two terms, ∑πc′(#(π) − 1)c#(π)−1, and ∑π∈SNCδ(n,−n)c#(π)/2, where SNCδ(n,−n) is a set of non-crossing annular permutations satisfying a symmetry condition. Moreover we present a recursion formula for the second term which is related to one for higher order freeness.
Layered double hydroxide for photocatalytic application toward CO2 reduction and water splitting: Recent advances, synthesis, heterojunction formation, challenges, and future directions
Authors: Khan Azmat Ali , Tahir Muhammad , Khan Nazish
Published: February 2025

Solar fuel production through water splitting and CO2 reduction by employing photocatalytic materials is a paradigm track to present renewable energy sources and lessen global warming. Among these materials, layered double hydroxides (LDHs) have been widely investigated in CO2 reduction and water splitting to produce chemical fuels. However, pure LDHs suffer from sluggish charge-carrier transport, a great electron–hole recombination rate as well as tend to cause agglomeration. Due to the aforementioned bottlenecks, numerous modification techniques have been considerably explored to enhance the potential of LDHs toward photocatalytic water splitting and CO2 photoreduction. Therefore, this article presents a thorough review of developments made for the construction and modification of LDH photocatalyst properties aiming to enhance water splitting and photocatalytic CO2 reduction. The review starts with the techniques adopted to synthesize LDH-based structures toward enhanced structure and morphology. The key semiconducting, optical, and electronic properties are studied to understand the conduct of LDH materials toward excellent photocatalytic material. The study then deliberates the techniques such as morphological engineering, hybridization with conducting and semiconducting materials, vacancy creation and defect engineering, components tuning, photothermal catalysis, heterojunction, and heterostructural engineering employed for the enrichment of photocatalytic properties. The study also discusses the steps taken to enhance the adsorption of LDHs and coupling of computational and operando techniques toward semiconducting, structural, and optical properties to investigate the best-performing photocatalysts. The study also reviews the recent advancements of LDH for applications toward water splitting and CO2 conversion.
Design and evaluation of a piezoelectric energy harvester using asymmetric clamping to improve output performance
Authors: Su Donghao , Wang Liang
Published: February 2025

This paper proposes a piezoelectric energy harvester using asymmetric clamping to improve output performance. The piezoelectric ceramics have a greater degree of deformation and a shorter response time during squeezing under the effect of the rectangular baffles, resulting in a higher voltage output than that from the structure without baffles. When the piezoelectric beams have rectangular baffles on both sides and the length is 8 mm, the prototype provides a high output voltage over a wide range, and the open-circuit peak–peak voltage is 60.8 V, which is 3.49 times that of the structure without baffles. The strength of the prototype and its feasibility in practice are verified by observing the brightness of the same number of LEDs; it shows great promise for powering microelectronic devices.
Ab initio investigation on the effect of solid solution RE on interface and mechanical properties of Al–Mg–Si alloy
Authors: Wang Yufei , Yao Tong , Miao Yaojun , Peng Peng , Gao Haiyan , Wang Jun , Sun Baode
Published: February 2025

Investigating the role of solid-solution rare earth elements (REs) in Al–Mg–Si alloys helps to gain a deeper understanding of the mechanisms of solid-solution elements, enabling the adjustment of alloy composition to improve the microstructure and overall performance of the alloy. This study employs first-principles computational methods to reveal the impact of rare earth element addition on the interface properties of α-Al/β″–Mg5Si6 and α-Al/β–Mg2Si in Al–Mg–Si alloys, as well as the effects on the mechanical properties of β″ and β precipitate phases. The study first constructs two interface models, Al(130)/Mg5Si6(100) and Al(001)/Mg2Si(001), to analyze their interface properties. Based on this, the substitution positions of rare earth elements in the interface models after their addition are further discussed. The results indicate that the atomic substitution positions of rare earth elements are related to crystal structure, interface properties, rare earth atomic radius, and electronegativity. Interface property studies show that the addition of rare earth elements significantly enhances the adhesion of Al(130)/Mg5Si6(100) and Al(001)/Mg2Si(001) interfaces, reduces interface energy, and strengthens interface stability. Additionally, the effects of rare earth element addition on the lattice mismatch of Al(130)/Mg5Si6(100) and Al(001)/Mg2Si(001) interfaces exhibit opposite trends and, to some extent, inhibit the β″ → β phase transformation. Mechanical property studies of the precipitate phases reveal that rare earth atoms in solid solution in β″ and β phases decrease the bulk modulus, shear modulus, and Young modulus, while increasing the Poisson ratio and B/G ratio. This indicates that the introduction of solid-solution rare earth elements reduces the alloy's stiffness and shear resistance while enhancing its plasticity and brittleness.
Investigation on phase formation and thermoelectric transport properties of CoTe2–CoSe2 solid solution alloys
Authors: Seon Seungchan , Kim BeomSoo , Lee Changwoo , Park Okmin , Cho Hyungyu , Kim Sang-il
Published: February 2025

CoTe2 and CoSe2 alloys have garnered considerable attention in thermoelectric applications due to their high electrical conductivity, tunable electronic properties, and potential for high power factors. In this study, the phase formation behavior and thermoelectric transport properties of a CoTe2–CoSe2 solid solution alloy were investigated by synthesizing a series of Co(Te1−xSex)2 compositions, where x = 0, 0.25, 0.50, 0.75, and 1.0. For x = 0, 0.25, and 0.50, the orthorhombic phase of CoTe2 was observed, while for x = 0.75, the orthorhombic phase of CoTe2 and cubic phase of CoSe2 coexisted. Up to x = 0.50, the power factor decreased slightly as the Hall mobility and the density-of-state effective mass decreased. The total thermal conductivity decreased as x increased to 0.50, owing to a decrease in the electronic and lattice thermal conductivity. Despite the decrease in total thermal conductivity, no significant increase in zT values was observed in the range of x = 0.25–0.50 due to a more pronounced decrease in the power factor. Nevertheless, cubic phase CoSe2 exhibited higher power factors and thus higher zT of 0.13 at 700 K. Further analysis based on single Kane band model suggests that significant enhancement in the power factor and zT could be achieved by reducing the carrier concentration from ∼1021 to ∼1019 cm−3 for all compositions.
Ultrafast laser 3D nanolithography of organic–inorganic hybrid waveguide devices
Authors: Zhu Dezhi , Jiang Shangben , Wang Ying , Liu Dejun , Bao Weijia , Liu Liwei , Qu Junle , Wang Yiping , Liao Changrui
Published: February 2025

On-chip micro- and nano-photonic structures are pivotal in modern industry, primarily due to their compact size, low transmission losses, and ease of integration. However, the three-dimensional (3D) bottom-up fabrication of on-chip functional structures, especially those made from inorganic materials rather than organic polymers, remains a challenge. Building inorganic devices with designed functional nanostructures on chips is critical for advancing microsystem applications. In this work, we propose a strategy for 3D nanolithography of on-chip waveguides using hybrid organic–inorganic materials through ultrafast laser-induced multiphoton absorption. The acrylate-functionalized precursors are locally cross-linked via nonlinear effects without the need for polymer additives. This process enables the direct integration of 3D photonic waveguides, resonators, and gratings onto chips, which exhibit strong stability due to densely packed silicon–oxygen molecular networks. This approach offers a promising solution for creating tailored inorganic micro- and nano-structures on chips, facilitating the development of advanced integrated functional devices.
Dissipative fractional standard maps: Riemann–Liouville and Caputo
Authors: Méndez-Bermúdez J. A. , Aguilar-Sánchez R.
Published: February 2025

In this study, given the inherent nature of dissipation in realistic dynamical systems, we explore the effects of dissipation within the context of fractional dynamics. Specifically, we consider the dissipative versions of two well known fractional maps: the Riemann–Liouville (RL) and the Caputo (C) fractional standard maps (fSMs). Both fSMs are two-dimensional nonlinear maps with memory given in action-angle variables (In,θn), with n being the discrete iteration time of the maps. In the dissipative versions, these fSMs are parameterized by the strength of nonlinearity K, the fractional order of the derivative α∈(1,2], and the dissipation strength γ∈(0,1]. In this work, we focus on the average action ⟨In⟩ and the average squared action ⟨In2⟩ when K≫1, i.e., along strongly chaotic orbits. We first demonstrate, for |I0|>K, that dissipation produces the exponential decay of the average action ⟨In⟩≈I0exp⁡(−γn) in both dissipative fSMs. Then, we show that while ⟨In2⟩RL−fSM barely depends on α (effects are visible only when α→1), any α<2 strongly influences the behavior of ⟨In2⟩C−fSM. We also derive an analytical expression able to describe ⟨In2⟩RL−fSM(K,α,γ).
Design of a multi-sensor walking boot to quantify the forefoot rocker motion as a function of walking speed
Authors: Park Jongcheon , Jung Hyunmok , Park Cheolhoon , Kim Seyoung
Published: February 2025

In this study, we designed a wearable multi-sensor walking boot to measure foot angular momentum and introduced a novel method to quantify forefoot rocker motion as a function of walking speed. A treadmill walking experiment was conducted with eight healthy subjects wearing the multi-sensor walking boot. Using the collected data, we calculated foot angular momentum and the average rate of change in angular momentum during the double support phase. In addition, we used linear regression analysis to quantify foot rotation patterns across increasing walking speeds, assessing the potential of this method as a walking indicator. The results demonstrated that the foot rotation pattern in the healthy group was characterized by a gradual scaling of angular momentum and its average rate of change, with strong correlations to walking speed. Based on these findings, we conclude that the proposed method for quantifying forefoot rocker motion relative to walking speed can serve as an effective indicator of normal walking.
Periodic solutions and chaotic attractors of a modified epidemiological SEIS model
Authors: Bestehorn Michael , Michelitsch Thomas M.
Published: February 2025

We consider a generalized SEIS (susceptible, exposed, infectious, and susceptible) model where individuals are divided into three compartments: S (healthy and susceptible), E (infected but not just infectious, or exposed), and I (infectious). Finite waiting times in the compartments yield a system of delay-differential or memory equations and may exhibit oscillatory (Hopf) instabilities of the otherwise stationary endemic state, leading normally to regular oscillations in the form of an attractive limit cycle in the phase space spanned by the compartment rates. In the present paper, our aim is to demonstrate that in the dynamics of delayed SEIS models, persistent chaotic attractors can bifurcate from these limit cycles and become accessible if the nonlinear interaction terms fulfill certain basic requirements, which to our knowledge were not addressed in the literature so far. Computing the largest Lyapunov exponent, we show that chaotic behavior exists in a wide parameter range. Finally, we discuss a more general system and show that a sudden falloff of the infection rate with respect to increasing infection number may be responsible for the emergence of chaotic time evolution. Such a falloff can describe mitigation measures, such as wearing masques, individual isolation, or vaccination. The model may have a wide range of interdisciplinary applications beyond epidemic spreading, for instance, in the kinetics of certain chemical reactions.
Optical emission spectroscopy and imaging of low-pressure N2 plasmas generated by intense fast-pulsed electron beams
Authors: Kaiser E. R. , Jackson S. L. , Swanekamp S. B. , Hinshelwood D. D. , Isner N. D. , Richardson A. S.
Published: February 2025

An optical emission spectroscopic (OES) and imaging characterization is conducted on N2 plasmas generated by a 100 keV fast-pulsed electron beam. The electron beams are injected into an N2 gas filled volume with a current of 4.5 kA (300 A/cm2) and a 100 ns pulse width. The characterization is conducted at the pressures, 1 Torr and 0.1 Torr, corresponding to two distinct regimes that exhibit significantly different plasma dynamics. Beam impact ionization is shown to be a primary mechanism for producing low temperature plasmas at 1 Torr during beam output. After beam termination, ionization by an inductive electric field becomes the primary mechanism for plasma formation later in time for both pressures. OES and plasma imaging are used in this work as a diagnostic tool to track the distribution of electronic, vibrational, and rotational state transitions and ionized species. This is achieved with the use of a multi-resolution suite of spectrometers capable of acquiring time-resolved spectra. Vibrational and rotational bands of the N2 second positive system (C3Πu→B3Πg) and the N2+ first negative system (B2Σu+→X2Σg+) are identified in both regimes as well as N+ states exclusively in the lower pressure regime. Vibrational and rotational spectra are shown to track the evolution of the time-varying plasma current. Plasma imaging also reveals spatially nonuniform plasma emission at 0.1 Torr. A few hundred shots are recorded to fully characterize the emissions, and results are shown to be highly reproducible (≤±1% with 2σ confidence).
Comparative study on charge photogeneration dynamics of Y small molecule and polymerized Y small molecule based polymer solar cells
Authors: Feng Junyi , Wen Guanzhao , Hu Rong , Yin Wenping , Zou Xianshao , Su Xiaojun , Zhong Jianbin , Dong Geng , Zhang Wei
Published: February 2025

Understanding charge photogeneration processes in polymer solar cells utilizing polymerized Y-molecule acceptors (PYMAs) is of great importance for design and optimization of high-performance solar cells. In this work, excited state dynamics in PYMAs (PYT, PY-DT) and corresponding solar cells were comparably studied with those of Y small molecules (Y5, Y6) by using the steady state and time-resolved spectroscopies as well as time-dependent density functional theory calculation. We find that PYMA (PYT, PY-DT) films exhibit smaller Stokes shifts than that of Y small molecules, indicating a more rigid backbone of PYMAs. Temperature-dependent steady-state PL measurement reveals that compared to small molecule films, the energy barrier from radiative to non-radiative states is smaller in PYMA films. In addition, transient absorption spectroscopy demonstrates that the exciton diffusion process in PYT and PY-DT are mainly intra-chain exciton diffusion mechanism with exciton diffusion coefficients of 1.7 × 10−2 and 2.7 × 10−2 cm2 s−1, respectively, in contrast with the inter-molecular exciton diffusion in Y5 and Y6 films. For the blend films, the phase sizes of acceptors in PM6:PYT and PM6:PY-DT are determined as 2.3 and 3.3 nm, respectively, smaller than that of Y6 (4.7 nm) in the PM6:Y6 film. In addition, unlike bimolecular recombination in classical system PM6:Y6, the PYMA-based all-polymer solar cells exhibit geminate type recombination in ultrafast timescale. We find that carrier lifetime plays a critical role in the performance of PYMA-based polymer solar cells. This work provides a comprehensive understanding of the photophysical properties of PYMAs, which is pivotal for designing highly efficient all-polymer solar cells.
Correlating the low-temperature photoluminescence with electron transport properties in cerium oxide thin film
Authors: Paul Mousri , Karmakar Sabyasachi , Sharma Jay , Bhunia Satyaban , Chakraborty Supratic
Published: February 2025

The complex interaction between the intrinsic and extrinsic state variables of strongly correlated insulator thin films is drawing interest as it shows memristive behavior that may be applicable to neuromorphic computing. Cerium oxide is an interesting material as its band structure is modified due to the formation of oxygen vacancy defects. The polaron formation that results from the reduction of the Ce4+ state to the Ce3+ state through oxygen vacancies is crucial for the electron transport in cerium oxide and is strongly influenced by temperature. In this work, we examined the relationship between the change in band structure and the associated conductivity at lower temperatures when ceria is exposed to light. Following light excitation, the creation of oxygen vacancies results in electron localization in the Ce 4f state, followed by the electron transition from 4f1 to 4f0, generating the PL spectra. With decreasing temperature, the lattice vibration decreases, and the splitting in the PL peak at a particular energy state validates the weaker electron–phonon interaction with an exciton trap. This reduces the carrier mobility of the film as observed from the resistance vs temperature curve of ceria under dark conditions. When excited by a particular energy of light, the electrons move more easily from the defect state to the conduction band, increasing conductivity at much lower temperatures than the conductivity under dark conditions.
Mechanism analysis of high-order harmonics acting on transonic shock buffeting
Authors: Jia Tian-hao , Gao Chao
Published: February 2025

Periodic oscillations of shock waves in transonic flow fields create very unstable aerodynamic loads that have a big effect on how safe an aircraft is and how well it handles. To elucidate the mechanism of transonic shock buffeting, a jet disturbance method is introduced and used to analyze the evolution of the flow field characteristics. First, the basic characteristics of buffeting are obtained through wind tunnel experiments. Numerical simulations are then conducted using the unsteady Reynolds-averaged Navier–Stokes equation based on the Reynolds stress model. The response of the global flow field to a jet disturbance enables the effects of the jet intervention time, jet withdrawal, and jet intensity to be studied. When the flow field is disturbed, the oscillations of the shock wave on the upper surface slow, and the buffeting load is reduced. An increase in jet strength suppresses the buffeting by preventing the factors that cause this phenomenon from exerting any influence. When the jet intensity exceeds a critical value, a complex multi-vortex structure and high-frequency pressure fluctuations appear at the trailing edge. In the presence of the jet disturbance, special high-order harmonics appear in the frequency spectrum, and high-frequency pressure waves occur in the global flow field. The fluctuating pressure generates high-order harmonics, and the trailing edge is the core position of transonic shock buffeting. The resulting high-frequency pressure waves are transmitted upstream, strengthening the shock wave–boundary layer interaction and causing shock oscillations.
Fast passage effect in cw-ODMR of an ensemble of NV− centers
Authors: Maki Yusuke , Matsuoka Hideto , Akimoto Ikuko
Published: February 2025

A rapid scan technique of the magnetic field has been developed to improve excitation efficiency in continuous wave (cw)-electron spin resonance. The resulting passage effects induce significant responses of magnetizations, most notably an inversion of longitudinal magnetization. The change in longitudinal magnetization can be observed in optically detected magnetic resonance (ODMR), but the passage effect has not been investigated in cw-ODMR spectroscopy. In this study, we combine the ODMR technique with the rapid scan of the magnetic field to demonstrate the impact of fast passage effects on the field-swept cw-ODMR. An ensemble of negatively charged nitrogen-vacancy (NV−) centers in a diamond crystal is used as a model system. By selecting the fast passage adiabatic region among six distinct passage regions, efficient ODMR detection is achieved through the macroscopic control of longitudinal magnetization. Experimental results are explained by the numerical analyses of classical time-dependent Bloch equations and related rate equations under an optical cycle. This knowledge paves the way for the facilitation of versatile applications of ODMR for quantum sensors.
Data-driven signal-to-noise enhancement in scattering near-field infrared microscopy
Authors: Baiz Carlos R. , Kanevche Katerina , Kozuch Jacek , Heberle Joachim
Published: February 2025

This study introduces a machine-learning approach to enhance signal-to-noise ratios in scattering-type scanning near-field optical microscopy (s-SNOM). While s-SNOM offers a high spatial resolution, its effectiveness is often hindered by low signal levels, particularly in weakly absorbing samples. To address these challenges, we utilize a data-driven “patch-based” machine learning reconstruction method, incorporating modern generative adversarial neural networks (CycleGANs) for denoising s-SNOM images. This method allows for flexible reconstruction of images of arbitrary sizes, a critical capability given the variable nature of scanned sample areas in point-scanning probe-based microscopies. The CycleGAN model is trained on unpaired sets of images captured at both rapid and extended acquisition times, thereby modeling instrument noise while preserving essential topographical and molecular information. The results show significant improvements in image quality, as indicated by higher structural similarity index and peak signal-to-noise ratio values, comparable to those obtained from images captured with four times the integration time. This method not only enhances image quality but also has the potential to reduce the overall data acquisition time, making high-resolution s-SNOM imaging more feasible for a wide range of biological and materials science applications.
Discretizing the bistability of mode-locked electron spin precession: An Overhauser field hysteresis manifestation
Authors: Kesto Estefanio , Dominguez Michael J. , Sih Vanessa
Published: February 2025

Electron-nuclear spin interactions by pulsed optical pumping have been found to polarize the nuclear spin system, leading to the nuclei building up an intrinsic magnetic field known as the Overhauser field. Studies have indicated an Overhauser field hysteresis effect dependent on the sweep direction of an externally applied magnetic field in negatively detuned periodically pumped Si-doped GaAs. Although predictions of bistable mode-locked electron spin precession frequency modes have been made for systems exhibiting this hysteresis, there have been no reports on the experimental observation of said bistable spin precession modes. This report details the evolution of bistable Overhauser field solutions leading to a hysteretic effect in negatively detuned optical excitation of Si-doped GaAs by magneto-optic pump–probe spectroscopy in the Voigt geometry and investigates the resulting consequence of this hysteresis acting on the electron spin system. One manifestation of the Overhauser field hysteresis acting on the electron spin system leads to the discretization of bistable mode-locked electron spin precession modes within a given band of externally applied magnetic fields. A method for preferentially accessing the two different and stable mode-locked spin precession modes within a given band of externally applied magnetic field is outlined, which may be of interest for communities utilizing electron and nuclear spins for information processing protocols.
Autonomous walking dynamics of a nanorobot on a nanopore track driven by salt concentration gradients
Authors: Sun Li-Zhen , Liu Xiu-Chong
Published: February 2025

The walking of a nanorobot with DNA legs requires a preset track to serve as footholds for the DNA legs and a track-matched driving mechanism to propel the nanorobot. Recently, a newly suggested track formed by multiple nanopores has garnered attraction due to its chemical stability. The nanorobot can be powered by biased leg-nanopore interactions along the walking direction. Here, we propose utilizing a salt concentration gradient along the nanopore track to induce an interaction bias based on different local ion screening effects on the nanopore charges. The nanorobot walking behaviors under different salt concentration gradients are studied through a combination of computational simulations and theoretical analyses. We find that the walking properties (such as velocity and directionality) highly depend on the local interactions experienced by the lagging leg. Under strong leg-nanopore attraction, the lagging leg needs a drag force provided by the leading leg to leave from the nanopore, while under weak attraction, the lagging leg can leave the nanopore without the assistance of the leading leg. Therefore, different walking modes can be observed under various ion conditions, leading to the complicated walking dynamics of the nanorobot driven by the salt concentration gradients.
Enhanced current-induced torque efficiency in Pt/Co/Tb/Cr structures through the synergistic action of orbital torque effect
Authors: Zhang Yu , Guo Yonghai , Zhang Bo , Wang Bo , Yan Ze , Lv Wenbo , Qi Xingrong , Wang Zhirui , Cao Jiangwei
Published: February 2025

We investigated the impact on the spin–orbit torque (SOT) efficiency by varying the thickness of the Cr and Tb layers in the Pt/Co/Tb/Cr system. The harmonic Hall voltage measurement shows that the Tb insert layer effectively enhances the damping-like (DL) torque efficiency, which is ascribed to the conversion of the orbital current to spin current in the Tb layer. Additionally, by fitting the Cr thickness dependence of the measured DL torque efficiency with an orbital current diffusion model, we obtained the orbital diffusion length of the Cr layer of 5.3 ± 0.3 nm and the effective orbital Hall angle of −0.18 ± 0.01. Furthermore, current-induced magnetization switching measurement suggested that the critical switching current density decreases with the insertion of the Tb layer and the increasing Cr layer thickness. Our findings offer valuable insights into the improvement of SOT efficiency by utilizing the orbital current effect and open avenues for developing energy-efficient spintronics devices.
Homogeneous linewidth behavior of narrow optical emitters at sub-kelvin temperatures
Authors: Lin X. , Hartman M. T. , Goldner P. , Fang B. , Le Coq Y. , Seidelin S.
Published: February 2025

We explore the properties of ultranarrow spectral holes in ensembles of solid-state emitters in crystals over a range of sub-kelvin temperatures, as a new step toward leveraging their exceptional coherence properties more effectively. As an example, we consider the potential gain observed in their application in frequency stabilization schemes. We investigate how the parameters used to burn the spectral hole impact its shape, and how these factors determine the minimum achievable linewidth. In addition to the stability of the hole's center frequency, the linewidth and contrast play a crucial role in frequency locking. At sub-kelvin temperatures, the temperature-dependent T7 broadening from two-phonon Raman scattering is expected to be negligible, and the spectral hole's linewidth should therefore remain constant in this interval. We observe however a linear broadening with increasing temperature, highlighting the need for further investigation into the mechanisms governing the linewidth at ultra-low temperatures.
Tuning the interfacial transport behavior in a superconducting van der Waals heterostructure
Authors: Zhu Shuangxing , Liu Hao , Tang Xiao-Fang , Wu Qi-Yi , Zhang Chen , Wu Jiaxin , Mei Junning , Zhang Ruan , Liu Ying , Chen Yu , Watanabe Kenji , Taniguchi Takashi , Cai Xinghan , Meng Jian-Qiao
Published: February 2025

The interaction between the metallic and superconducting components at the interface of superconductor–normal metal (S-N) systems enables a variety of quantum phenomena, including the Josephson effect, Andreev reflection, and proximity-induced superconductivity, which are of significant interest both theoretically and practically. Nevertheless, due to varying physical mechanisms, achieving and fine-tuning multiple such phenomena within a single S-N system continues to be a challenge. In this work, we employ NbSe2 and WTe2 to fabricate an S-N-S heterostructure. Below the superconducting transition temperature of NbSe2, two distinct resistance-temperature behaviors are observed: a continuous decrease in junction resistance with temperature decrease, indicative of the superconducting proximity effect and consistent with the BCS model, and an increase in resistance attributed to competition between Andreev reflection (AR) and normal reflection at a low-transparency interface, which can be suppressed by applying a small bias current or a magnetic field. Our results indicate the signature of the coexistence of proximity-induced superconductivity with AR in the measured S-N-S heterojunction, demonstrating the tunability of charge carrier transport behavior at the interface. This finding enhances our understanding of such systems and holds potential for the development of superconducting electronics, quantum computing, and energy harvesting technologies.
Prediction and control of the vibration radiation noise of a multifunctional straw kneading machine shell
Authors: Pei Gang , Zhai Zhiping , Lan Yuezheng , Zhang Xinhai , Gao Bo
Published: February 2025

Multifunctional straw kneading machines experience significant issues, such as severe shell vibrations and considerable radiated noise during operation. To accurately predict and control the vibration and radiated noise of the machine shell during the design phase, a thorough analysis and calculation of the excitation sources were conducted. These sources include the pulsating pressure on the casing caused by the internal coupled flow field and the unbalanced dynamic force of the rotor system. A vibration response analysis of the kneading machine shell was carried out, and the results were utilized to determine acoustic boundary conditions. The acoustic transfer vector and modal acoustic transfer vector methods were applied to forecast the vibration radiation noise emitted from the shell numerically. The precision of this noise prediction model and methodology was confirmed through experimental noise measurements, and the influence of each excitation source on the vibration radiation noise of the shell is discussed. The panel acoustic contribution analysis approach was used to optimize the structural design of the kneading machine shell to effectively manage and reduce vibration and radiated noise. The results show that both the numerically predicted and experimentally measured sound pressure levels (SPLs) exhibit consistent trends, with the peak SPL frequencies closely aligned. The maximum discrepancy between the simulated and measured total SPL was 2.42 dB(A), validating the accuracy of the vibration radiation noise prediction model. Following structural modifications, significant reductions in the surface vibration velocity, radiation noise frequency band SPL, and total SPL of the machine shell were observed. The total sound pressure level at the measuring points in front of the pulley, the lower discharge outlet, and the upper discharge outlet are below the 90 dB(A) threshold specified by the national standard. The research findings offer valuable insights into the effective design and noise control of low-vibration radiation noise in similar machinery.
Heat transfer characteristics of a flat plate pulsating heat pipe with microstructures for unidirectional thermal-to-mechanical energy conversion
Authors: Zhang Qian , Tan Si-Cong , Zhu Jia-Min , Jiang Yu-Yan , Guo Cong
Published: February 2025

The phase change of a liquid into vapor results in a sharp volume expansion, generating a powerful driving force, which is fundamental for the operation of pulsating heat pipes (PHPs). However, the performance of PHPs is hindered by instability arising from the lack of directional control over the expansion process. In this work, we propose a PHP incorporating thermal-to-mechanical energy conversion (TMC) microstructures, which direct the TMC by controlling the expansion in desired directions, thereby more efficiently utilizing the driving force. Two designs for enhancement of TMC, i.e., one featuring a vapor actuator microstructure (VA-PHP) and another with diameter-variant channels (DVC-PHP), were fabricated and experimentally investigated under low inclination angles and horizontal orientations (0°, 1°, 5°, and 9°). The experimental results indicated that the incorporation of the TMC microstructures into the PHPs facilitated more efficient startup, enhanced unidirectional circulation, and reduced the dependence on the inclination angle. Notably, while the conventional PHP failed to operate at small inclination angles, the VA-PHP achieved stable operation at 1°, and the DVC-PHP further maintained stable operation even at 0°. The robust performance of the proposed PHPs at low inclination angles demonstrates the potential of TMC microstructures to overcome orientation-dependent limitations, thereby delivering a practical solution for improving the effectiveness of PHPs.
On the influence of optically controlled thermocapillary flow during vertical convective assembly: Origin of remora disk-like patterns
Authors: Ragisha Chetteente Meethal , Habeeb Nihal Muhammed , Grace Vijayan Lija , Ranganathan Panneerselvam , Varanakkottu Subramanyan Namboodiri
Published: February 2025

Vertical convective assembly, a cost-effective and efficient colloidal assembly strategy, has garnered interest from a wide range of disciplines, including photonics and sensors. In this work, we reveal the role of nonuniform temperature distribution at the three-phase contact line (TPCL) during the vertical lifting of the substrate from the colloidal suspension. Conventionally, vertical assembly is performed under isothermal conditions, and the possible outcomes are uniform particle deposits and discrete lines based on stick-slip behavior. We demonstrate that exposing the TPCL with a nearly Gaussian-type temperature profile under an optimal lifting speed of 0.8–5 μm/s results in a new kind of particle pattern, which we call remora disk-like assembly, with periodic central thick regions and lamella-kind structures on either side. We generate the required temperature gradient by irradiating the TPCL with a laser beam, whose emission wavelength matches the plasmonic excitation of the nanoparticles used (λ = 532 nm). The nonuniform temperature distribution at the TPCL (ΔT = 13 °C) generates a corresponding thermocapillary flow, which drives the particles toward the TPCL in a gradient manner. We develop a physical model to explain the particle deposition mechanism, the nature of the remora disk assembly, and the asymmetric depinning behavior of the meniscus. Furthermore, by varying the lifting speed, we could tune the morphology and spacing of the patterns. We believe the new insights on the particle dynamics under optically controlled thermocapillary flow could significantly contribute to the fundamental understanding as well as enriching the applied aspects of the vertical lifting-based colloidal lithography.
Formation and regulation of calcium sparks on a nonlinear spatial network of ryanodine receptors
Authors: Li Tian-Tian , Gao Zhong-Xue , Ding Zuo-Ming , Jiang Han-Yu , He Jun
Published: February 2025

Accurate regulation of calcium release is essential for cellular signaling, with the spatial distribution of ryanodine receptors (RyRs) playing a critical role. In this study, we present a nonlinear spatial network model that simulates RyR spatial organization to investigate calcium release dynamics by integrating RyR behavior, calcium buffering, and calsequestrin (CSQ) regulation. The model successfully reproduces calcium sparks, shedding light on their initiation, duration, and termination mechanisms under clamped calcium conditions. Our simulations demonstrate that RyR clusters act as on-off switches for calcium release, producing short-lived calcium quarks and longer-lasting calcium sparks based on distinct activation patterns. Spark termination is governed by calcium gradients and stochastic RyR dynamics, with CSQ facilitating RyR closure and spark termination. We also uncover the dual role of CSQ as both a calcium buffer and a regulator of RyRs. Elevated CSQ levels prolong calcium release due to buffering effects, while CSQ-RyR interactions induce excessive refractoriness, a phenomenon linked to pathological conditions such as ventricular arrhythmias. Dysregulated CSQ function disrupts the on-off switching behavior of RyRs, impairing calcium release dynamics. These findings provide new insights into RyR-mediated calcium signaling, highlighting CSQ’s pivotal role in maintaining calcium homeostasis and its implications for pathological conditions. This work advances the understanding of calcium spark regulation and underscores its significance for cardiomyocyte function.
Effects of surrounding urban morphology and wind direction on hazardous gas dispersion from chemical plants: Morphological analysis and fluid dynamics insights into industry–urban interactions
Authors: Yang Jianzhi , Wu Lingbo , Li Rui , Liu Xianghua , Tao Changfa
Published: February 2025

This study investigates the influence of urban morphology and wind direction on the dispersion of hazardous gases from chemical plants located near residential areas, emphasizing the urgent need for effective safety and risk management as industrial sites expand. By addressing critical gaps in understanding how urban configurations and prevailing winds affect gas dispersion, this work provides essential insights for enhancing public safety. Through a statistical analysis of 121 chemical plants, we classify common residential configurations surrounding these facilities, with a notable prevalence of single-sided and double-sided arrangements. We develop three-dimensional geometric models and conduct Computational Fluid Dynamics simulations to analyze the dispersion of heavy hazardous gases under varying wind conditions. Our findings reveal that urban morphology and wind direction significantly affect airflow, turbulence, and gas dispersion patterns, with high-density configurations leading to increased exposure risks and fatality rates, while lower-density, staggered arrangements facilitate smoother gas dispersion and reduce associated risks. The results emphasize the critical importance of considering building density, layout, and wind direction in urban planning to enhance safety in industrial-residential interfaces. Recommendations include reducing building density and optimizing street orientations to mitigate the impact of hazardous gas releases, thereby improving public safety in urban environments.
An upscaling framework for predicting gas multiscale transport behavior in shale matrix-microfracture systems considering microscopic transport mechanisms
Authors: Yin Ying , Wang Hui , Zuo Hong , Zhang Tao
Published: February 2025

Predicting gas production in shale rock is challenging due to the complex multiscale processes ranging from nanometer to micrometer-scale, complex components including the resolved (e.g., microfractures) and the unresolved components (e.g., nanoscale pores in inorganic and organic matters), and microscopic transport mechanisms such as the slip effect, surface diffusion, and the real gas effect. To this end, a comprehensive upscaling framework is proposed in this paper to mimic the multiscale gas transport processes in shale matrix microfracture systems. Here, the microscopic transport mechanisms are considered by a modified nanopore model, and then, upscaled to the matrix scale by the generalized lattice Boltzmann model. Using the proposed upscaling framework, we analyze the variations of apparent permeabilities with pressure and matrix porosity and the enhancement of gas transport capability by microscopic effects (slip effect and surface diffusion) and microfractures (orientation and aperture). The results show that the improvement in apparent permeability due to the microfractures is ∼1.70 times that of the basic shale matrix, while the improvement due to microscopic effects (at a pressure drop from 20 MPa to 1 MPa) is only 1.03 times. This indicates that the microfractures significantly affect the gas transport compared to the reduced pressure. More importantly, the microfracture aperture substantially affects the transport performance, especially when aligned with the flow direction. Increasing the aperture from 2 μm to 3 μm leads to a ∼2.56-fold improvement in transport capability. These findings contribute to more accurately estimating gas transport performance in shale with microfractures.
Influences and variations of wave impedance of electromagnetic fields generated by lightning return strokes
Authors: Yu Jianli , Xu Guosheng , Gu Shanmao , Liu Jianjun , Li Quanxin
Published: February 2025

The domains of lightning electromagnetic pulse (LEMP) fields are classified as “near-field,” “intermediate-field,” and “far-field” based on qualitative descriptions. However, the systematic quantitative classification of LEMP fields is yet to be reported. This study characterized the wave impedance of lightning electromagnetic pulse (WILEMP) to solve this problem. The components and field domain distribution ranges of LEMP were analyzed by varying the WILEMP and the distance between the observation point and radiation source (r). The changes in the WILEMP with r under the influence of different factors were calculated using the finite-difference time-domain (FDTD) method. The results indicated that the LEMP field has high impedance. the WILEMP decreased rapidly with the increase in r when r ≤ 10 km, consistent with the characteristics of the electrostatic and induction fields (near field). The WILEMP gradually decreased and stabilized with the increase in r when r ≥ 20 km, and the value was roughly the same as the impedance of free space (377 Ω) when r = 100 km, consistent with the characteristics of radiation field (far field). The decay rate of the WILEMP was lower than that when r ≤ 10 km but higher than that when r ≥ 20 km. Finally, when 10 km < r < 20 km, the apparent transitivity was consistent with intermediate-field characteristics.
Methane release and energy evolution in coal and its implication for gas outburst
Authors: Li Xiangchun , Si Xiaopeng , Li Xiaowei , Zhang Shuhao , Yang Tao , Hu Linjie , Nie Baisheng , Li Zhongbei
Published: February 2025

Gas outburst is a common underground geological hazard that poses a serious threat to coal mine safety production. To elucidate the influence of methane release behavior and energy evolution on gas outburst in coal, the microscopic pore parameters and macroscopic methane release law of six coal rank samples were studied by full-scale pore test, Scanning electron microscopy-Pores and Cracks Analysis System analysis and temperature measurement experiments during methane desorption. The results show that with the increase in coal rank, pore complexity, and the chaos of pore direction distribution first decrease and then increase. The pore volume and pore area of low/high-rank samples are relatively large, with well-developed pores, especially micropores, which are prone to gas accumulation and have great potential for outburst. The evolution of methane desorption-diffusion performance with coal rank is corresponding to pore development degree, methane in high rank coal is rapidly transferred at a high diffusion rate. The desorption prediction model related to temperature change can accurately characterize the relationship between temperature variation and desorption amount in the process of methane desorption. With the increase in coal rank, the desorption heat value and gas expansion energy of samples show a U-shaped trend of decreasing first and then increasing. In high-rank coal seams, large methane potential energy accumulates, posing considerable outburst potential and threats. The research findings can provide certain guidance for the prediction and forecasting of gas outburst disasters.