bluuebunny/crossref_metadata_2025 huggingface dataset:
Gravity measurement at the sub-millimeter scale with optical lattice clock
Authors: Xiao Sheng-Xian , Liang Ying , Zhang Ya , Wang Tao
Published: February 2024

Due to the excellent accuracy, the optical lattice clock (OLC) has not only achieved impressive results in frequency measurement but also gradually plays an important role in quantum precision measurement. In this paper, we propose a scheme for measuring gravity at the sub-millimeter scale extracted from the Rabi spectrum based on Super-Bloch oscillations of atoms in the OLC. Our proposal can be realized on the existing OLC platform without significant change. Under realistic existing experimental parameters of 87Sr OLC, we determine the optimal experimental conditions and obtain a sensitivity of 5μGal/Hz in the quantum projection noise limit, which is 50 times better than the previous method at the sub-millimeter scale under the same consideration. Another advantage of our proposal is that it is insensitive to the noise of the lattice laser, which contributes to the major uncertainty of the previous measurement (PRA 86, 033615). Our research will promote the development of OLC geoscopy.
Site-specific electronic structure of covalently linked bimetallic dyads from nitrogen K-edge x-ray absorption spectroscopy
Authors: Ryland Elizabeth S. , Liu Xiaolin , Kumar Gaurav , Raj Sumana L. , Xie Zhu-Lin , Mengele Alexander K. , Fauth Sven S. , Siewerth Kevin , Dietzek-Ivanšić Benjamin , Rau Sven , Mulfort Karen L. , Li Xiaosong , Cordones Amy A.
Published: February 2024

A nitrogen K-edge x-ray absorption near-edge structure (XANES) survey is presented for tetrapyrido[3,2-a:2′,3′-c:3″,2″-h:2‴,3‴-j]phenazine (tpphz)-bridged bimetallic assemblies that couple chromophore and catalyst transition metal complexes for light driven catalysis, as well as their individual molecular constituents. We demonstrate the high N site sensitivity of the N pre-edge XANES features, which are energetically well-separated for the phenazine bridge N atoms and for the individual metal-bound N atoms of the inner coordination sphere ligands. By comparison with the time-dependent density functional theory calculated spectra, we determine the origins of these distinguishable spectral features. We find that metal coordination generates large shifts toward higher energy for the metal-bound N atoms, with increasing shift for 3d < 4d < 5d metal bonding. This is attributed to increasing ligand-to-metal σ donation that increases the effective charge of the bound N atoms and stabilizes the N 1s core electrons. In contrast, the phenazine bridge N pre-edge peak is found at a lower energy due to stabilization of the low energy electron accepting orbital localized on the phenazine motif. While no sensitivity to ground state electronic coupling between the individual molecular subunits was observed, the spectra are sensitive to structural distortions of the tpphz bridge. These results demonstrate N K-edge XANES as a local probe of electronic structure in large bridging ligand motifs, able to distinctly investigate the ligand-centered orbitals involved in metal-to-ligand and ligand-to-ligand electron transfer following light absorption.
Layered carbon nitride films deposited under an oxygen-containing atmosphere and their electronic properties
Authors: Higuchi Kota , Tachibana Masaki , Urakami Noriyuki , Hashimoto Yoshio
Published: February 2024

Layered carbon nitride (g-C3N4) is a novel semiconducting and functional material for optoelectronic applications. The physical and chemical properties of g-C3N4 films differ depending on the preparation atmosphere. Herein, we deposited g-C3N4 films under a mixed oxygen (O2)-nitrogen (N2) gas atmosphere and studied their effects on the carrier transport properties. Although no significant change in the film orientation was observed, the deposition rate decreased as the O2 gas ratio in the mixed N2/O2 atmosphere increased. Despite their thinness, the luminescence intensity of g-C3N4 films deposited under an O2-containing atmosphere increased by 3.5–5.0 times compared to that deposited under an N2 atmosphere. With respect to voltage application, carrier transport owing to the thermionic emission and/or direct tunneling initially followed ohmic conduction, followed by insufficient trap-filled conduction. As the applied voltage increased further, fully trap-filled conduction was confirmed owing to Fowler–Nordheim tunneling. Moreover, the conductivity type could be changed to p-type and n-type using N2 gas and mixed N2/O2 gas atmospheres, respectively, during film deposition. In addition to the intrinsic transport properties, the intentionally formed Schottky barrier also affected the carrier transport; therefore, the diode-like rectifying behavior of the current density was achieved.
Improving the endurance for ferroelectric Hf0.5Zr0.5O2 thin films by interface and defect engineering
Authors: Zhou Jing , Guan Yue , Meng Miao , Hong Peizhen , Ning Shuai , Luo Feng
Published: February 2024

Improving the endurance performance for hafnia-based ferroelectric thin films and devices is of considerable significance from both scientific and technological perspectives. Here, we obtained robust ferroelectricity in Hf0.5Zr0.5O2 (HZO) thin films without the need of the confinement from top electrodes by systematically optimizing the conditions and parameters for the post-deposition annealing (PDA) process. Compared with the post-metallization annealing (PMA) process, PDA is found to markedly improve the ferroelectric endurance performance. In particular, wake-up-free ferroelectric HZO thin films with an exceptional endurance performance (∼3 × 1010 cycles) are obtained by PDA processing conducted under an oxygen atmosphere, which is attributed to the suppression of oxygen deficiency in the HZO thin films and the inhibition of interfacial reaction layer that inevitably forms during annealing treatment for PMA processing. Our work offers insight into improving ferroelectricity and endurance for hafnia-based ferroelectric materials and devices.
Modulation of trap distribution by optimizing Mn2+ doping in CsCdCl3 crystals toward enhanced afterglow performance
Authors: Yang Ruoting , Ji Huifang , Zhao Dengbang , Zhang Fei , Ji Xinzhen , Wang Meng , Zhang Mengyao , Jia Mochen , Chen Xu , Liu Ying , Wu Di , Li Xin Jian , Shi Zhifeng
Published: February 2024

Exploring efficient and stable long-persistent luminescence (LPL) materials is of great value for promoting their advanced applications. Here, the metal halide CsCdCl3:Mn2+ crystals with tunable afterglow properties and good stability were grown by a facile solution method. Upon ultraviolet excitation, CsCdCl3:Mn2+ crystals exhibited a bright orange emission at 590 nm from the d–d transition of Mn2+ ions. Mn2+ doping concentrations matter for the LPL performance. By optimizing the doping amount of Mn2+, an enhanced afterglow duration up to 12 000 s was achieved, compared with undoped sample, originating from a trap redistribution. The deep traps in CsCdCl3:0.1Mn2+ crystal that provide little contribution to the LPL at room temperature shifted to shallow levels, thus synergistically enhancing the afterglow intensity and duration. Based on the variable afterglow durations by tuning Mn2+ doping concentrations, a multi-dimensional information storage encryption model was designed. This work gives deep understanding in doping effect on the afterglow and provides examples for the development of multi-dimensional information encryption.
Effects of interface model on performance of a vortex pump in CFD simulations
Authors: Li Wenguang
Published: February 2024

That the predicted head of a vortex pump is higher than that measured experimentally is very common in simulations of turbulent flow in such pumps. To identify why, reported here is a study of the turbulent flow of water in a vortex pump with a specific speed of 76 and fluid domains with 1/8-impeller and whole-impeller geometrical models and smooth walls using the 3D steady Reynolds-averaged Navier–Stokes equations, the standard k–ɛ model, and a scalable wall function in ANSYS CFX 2019 R2. The results show that the aforementioned phenomenon is related to the choice of interface model. With the 1/8-impeller model, the head predicted by the frozen rotor model agrees with the experimental head. By contrast, the transient rotor model provides a reasonably accurate head against the experimental head but requires huge computing resources and overestimates the pump efficiency, and the stage model is unsuitable for predicting the head of the pump. The flow patterns in the vaneless chamber and impeller predicted with the 1/8-impeller model are more uniform because of artificial fluid mixing on the interface than those predicted with the whole-impeller model by using the frozen rotor model, and the flow patterns predicted with the whole-impeller model by using the transient rotor model are in between. The hydraulic performance of the pump is predicted with the 1/8-impeller model and frozen rotor model at various viscosities, and the flow-rate, head, and efficiency correction factors are determined and correlated with the impeller Reynolds number.
Global diversity of enterococci and description of 18 previously unknown species
Authors: Schwartzman Julia A. , Lebreton Francois , Salamzade Rauf , Shea Terrance , Martin Melissa J. , Schaufler Katharina , Urhan Aysun , Abeel Thomas , Camargo Ilana L. B. C. , Sgardioli Bruna F. , Prichula Janira , Guedes Frazzon Ana Paula , Giribet Gonzalo , Van Tyne Daria , Treinish Gregg , Innis Charles J. , Wagenaar Jaap A. , Whipple Ryan M. , Manson Abigail L. , Earl Ashlee M. , Gilmore Michael S.
Published: February 2024

Enterococci are gut microbes of most land animals. Likely appearing first in the guts of arthropods as they moved onto land, they diversified over hundreds of millions of years adapting to evolving hosts and host diets. Over 60 enterococcal species are now known. Two species,
Enterococcus faecalis
and
Enterococcus faecium,
are common constituents of the human microbiome. They are also now leading causes of multidrug-resistant hospital-associated infection. The basis for host association of enterococcal species is unknown. To begin identifying traits that drive host association, we collected 886 enterococcal strains from widely diverse hosts, ecologies, and geographies. This identified 18 previously undescribed species expanding genus diversity by >25%. These species harbor diverse genes including toxins and systems for detoxification and resource acquisition.
Enterococcus faecalis
and
E. faecium
were isolated from diverse hosts highlighting their generalist properties. Most other species showed a more restricted distribution indicative of specialized host association. The expanded species diversity permitted the
Enterococcus
genus phylogeny to be viewed with unprecedented resolution, allowing features to be identified that distinguish its four deeply rooted clades, and the entry of genes associated with range expansion such as B-vitamin biosynthesis and flagellar motility to be mapped to the phylogeny. This work provides an unprecedentedly broad and deep view of the genus
Enterococcus
, including insights into its evolution, potential new threats to human health, and where substantial additional enterococcal diversity is likely to be found.
Haplorchis infections in intermediate hosts from a clonorchiasis endemic area in Meinung, Taiwan, Republic of China
Authors: Wang Jiun-Jye , Chung Lee-Yii , Lee June-Der , Chang Eddy-Essen , Chen Eng-Rin , Chao David , Yen Chuan-Min
Published: February 2024

Snails and freshwater fish were examined from four ponds in the Meinung township in which Clonorchis sinensis was known to be endemic 18 years ago. No metacercariae were found in 478 Tilapia nilotica, whereas of 451 Ctenopharyngodon idellus examined, 16.2%, 3.3% and 0.9% were found to be infected with Haplorchis pumilio, H. taichui and Clonorchis sinensis, respectively. In addition, there were some unidentified metacercariae in 12.0% of Ctenopharyngodon idellus examined. Overall, no positive correlation between infection rates and sizes of infected fish was shown. Six species of snails were collected in this survey and two frequently-occurring snails, Melanoides tuberculata and Thiara granifera were commonly infected with H. pumilio. Reasons for the prevalence of Haplorchis species and the absence of Clonorchis sinensis in fish and snail hosts in a previously reported endemic area for human clonorchiasis are discussed.
Rare SH2B3 coding variants in lupus patients impair B cell tolerance and predispose to autoimmunity
Authors: Zhang Yaoyuan , Morris Rhiannon , Brown Grant J. , Lorenzo Ayla May D. , Meng Xiangpeng , Kershaw Nadia J. , Kiridena Pamudika , Burgio Gaétan , Gross Simon , Cappello Jean Y. , Shen Qian , Wang Hao , Turnbull Cynthia , Lea-Henry Tom , Stanley Maurice , Yu Zhijia , Ballard Fiona D. , Chuah Aaron , Lee James C. , Hatch Ann-Maree , Enders Anselm , Masters Seth L. , Headley Alexander P. , Trnka Peter , Mallon Dominic , Fletcher Jeffery T. , Walters Giles D. , Šestan Mario , Jelušić Marija , Cook Matthew C. , Athanasopoulos Vicki , Fulcher David A. , Babon Jeffrey J. , Vinuesa Carola G. , Ellyard Julia I.
Published: February 2024

Systemic lupus erythematosus (SLE) is a heterogeneous autoimmune disease with a clear genetic component. While most SLE patients carry rare gene variants in lupus risk genes, little is known about their contribution to disease pathogenesis. Amongst them, SH2B3—a negative regulator of cytokine and growth factor receptor signaling—harbors rare coding variants in over 5% of SLE patients. Here, we show that unlike the variant found exclusively in healthy controls, SH2B3 rare variants found in lupus patients are predominantly hypomorphic alleles, failing to suppress IFNGR signaling via JAK2-STAT1. The generation of two mouse lines carrying patients’ variants revealed that SH2B3 is important in limiting the number of immature and transitional B cells. Furthermore, hypomorphic SH2B3 was shown to impair the negative selection of immature/transitional self-reactive B cells and accelerate autoimmunity in sensitized mice, at least in part due to increased IL-4R signaling and BAFF-R expression. This work identifies a previously unappreciated role for SH2B3 in human B cell tolerance and lupus risk.
Experimental Investigation of the Anisotropic Thermal Conductivity of C/SiC Composite Thin Slab
Authors: Wu 毋 Ke-Fan 克凡 , Zhang 张 Hu 虎 , Tang 唐 Gui-Hua 桂华
Published: February 2024

Fiber-reinforced composites possess anisotropic mechanical and heat transfer properties due to their anisotropic fibers and structure distribution. In C/SiC composites, the out-of-plane thermal conductivity has mainly been studied, whereas the in-plane thermal conductivity has received less attention due to their limited thickness. In this study, the slab module of a transient plane source method is adopted to measure the in-plane thermal conductivity of a 2D plain woven C/SiC composite slab, and the test uncertainty is analyzed numerically. The numerical investigation proves that the slab module is reliable for measuring the isotropic and anisotropic slabs with in-plane thermal conductivity greater than 10 W⋅m−1⋅K−1. The anisotropic thermal conductivity of the 2D plain woven C/SiC composite slab is obtained within the temperature range of 20–900 °C by combining with a laser flash analysis method to measure the out-of-plane thermal conductivity. The results demonstrate that the out-of-plane thermal conductivity of C/SiC composite decreases with temperature, while its in-plane thermal conductivity first increases with temperature and then decreases, and the ratio of in-plane thermal conductivity to out-of-plane thermal conductivity is within 2.2–3.1.
Affine linking number estimates for the number of times an observer sees a star
Authors: Chernov Vladimir , Maguire Ryan
Published: February 2024

Affine linking numbers are the generalization of linking numbers to the case of nonzero homologous linked submanifolds. They were introduced by Rudyak and the first author who used them to study causality in globally hyperbolic spacetimes.

In this paper we use affine linking numbers to estimate the number of times an observer sees light from a star, that is how many copies of the star do they see on the sky due to gravitational lensing.
Both experimental and molecular dynamics approaches highlight the central role of interfacial water for radical production by irradiated gold nanoparticles
Authors: Brun Emilie , Tandiana Rika , Gilles Manon , Cheref Yannis , Van-Oanh Nguyen-Thi , Clavaguera Carine , Sicard-Roselli Cécile
Published: February 2024

Nanoparticles devoted to improve radiotherapy treatments are an efficient tool if they can induce the formation of deleterious species in the tumor. Their interaction with radiation is responsible for radical production but in spite of the numerous studies mostly with cells, no consensus has been reached about radical formation mechanism. In order to gain knowledge in the physico-chemical step of this phenomenon, we applied a very sensitive test to quantify hydroxyl radicals and electrons produced when gold atoms, organized as nanoparticles or as a salt in solution, are irradiated by keV and MeV photons (x- and γ- rays). The crucial role of interfacial water is suggested to explain the high quantity of radicals measured for nanoparticles. These experimental data were supplemented by classical molecular dynamics simulations, revealing a specific organization of the water hydrogen bonding network at the nanoparticle surface which could be a key component in the mechanism of radical production by irradiated colloidal suspensions.
Controllable single-photon transport mediated by a time-modulated Jaynes–Cummings model
Authors: Li Haozhen , Lan Yang , Zeng Ran , Hu Miao , Xu Mengmeng , Xia Xiuwen , Xu Jingping , Yang Yaping
Published: February 2024

Controllable single-photon scattering in a one-dimensional waveguide coupled to a Jaynes–Cummings structure containing a time-modulated two-level atom interacting with a single-mode cavity is investigated. The photon transmission and reflection amplitudes are calculated by using an effective Floquet Hamiltonian in real space. The results show that the coupling between the atom and the cavity mode can dynamically be tuned via periodically modulating the atomic transition frequency. As a consequence, the scattering behaviors of the waveguide photons can be actively manipulated, and a controllable single-photon switch with high on-off ratio could be realized. More interestingly, the switch works well within a wide frequency region, i.e., the transmission of both resonant and off-resonant waveguide photons can be effectively switched on or off with appropriate system parameters. Furthermore, the proposed dynamically tunable switching scheme is robust against atomic dissipation associated with the help of atom-cavity coupling mismatch. Such single-photon device can be used as an elementary unit for various quantum information processing.
High harmonic generation in monolayer indium nitride
Authors: Liu Xiaoyu , Ji Zhiqiang , Wu Chenglong , Li Shasha , Wu Hong , Li Feng , Pu Yong
Published: February 2024

In our work, we theoretically investigate high harmonic generation (HHG) in monolayer hexagonal indium nitride (h-InN) based on the semiconductor Bloch equation under strong laser fields. Compared with h-BN, there is no multiplateau in h-InN. This is because the intraband mechanism dominates the total HHG, and the harmonic generated by the intraband current is about three orders of magnitude higher than that generated by the interband polarization. We find that the higher order part of the HHG is mainly supplied by the interband current, which can be analyzed on the basis of the transition dipole moments between the energy bands. In addition, we found that the HHG of h-InN is sensitive to the external strains due to the modified band dispersion in the electronic structures. This study provides a useful reference for understanding the microscopic mechanism of laser-solid interaction.
Quantum optics in MATLAB
Authors: Meher Nilakantha
Published: February 2024

We provide a MATLAB numerical guide at the beginner level to support students starting their research careers in theoretical quantum optics and related areas. These resources are also valuable for undergraduate and graduate students working on semester projects in similar fields.
Using ‘designer’ coherences to control electron transfer in a model bis(hydrazine) radical cation: can we still distinguish between direct and superexchange mechanisms?
Authors: Deumal Mercè , Ribas-Ariño Jordi , Robb Michael A
Published: February 2024

We have simulated two mechanisms, direct and superexchange, for the electron transfer in a model Bis(hydrazine) Radical Cation, which consists of two hydrazine moieties coupled by a benzene ring. The computations, that are inspired by the attochemistry approach, focus on the electron dynamics arising from a coherent superposition of four cationic states. The electron dynamics, originating from a solution of the time dependent Schrödinger equation within the Ehrenfest method, is coupled to the relaxation of the nuclei. Both direct (ca. 15 fs dynamics) and superexchange (ca. 2 fs dynamics) mechanisms are observed and turn out to lie on a continuum depending on the strength of the coupling of the benzene bridge electron dynamics with the hydrazine chromophore dynamics. This contrasts with the chemical pathway approach where the direct mechanism is completely non-adiabatic via a conical intersection, while the superexchange mechanism involves an intermediate radical with the unpaired electron localized on the benzene ring. Thus, with the attochemistry-inspired electron dynamics approach, one can distinguish direct from superexchange mechanisms depending on the strength of the coupling of two types of electron dynamics: the slow hydrazine dynamics (ca. 15 fs) and the fast benzene linker dynamics (ca. 2 fs). In this model bis(hydrazine) radical cation, only when the intermediate coupler is in an anti-quinoid state, does one see the coupling of the bridge and hydrazine chromophore dynamics.
The influence of Pt islands on the failure of Pt thin film on a flexible PET substrate
Authors: Du Du , Huang Han , Lu Mingyuan
Published: February 2024

Flexible electronic devices must adapt to compliant polymeric substrates, thus maintaining the mechanical integrity of the multilayer systems is crucial. This study investigates the mechanical failure caused by active islands, focusing on how Pt islands influence the failure mechanism of a thin Pt film on a flexible polyethylene terephthalate (PET) substrate under uniaxial tensile loading. Tensile testing of the Pt film/PET bilayer revealed a failure progression in the Pt blanket film, characterized by crack initiation, elongation and merging, eventually delamination, and buckling, with the increase in tensile strain. Pt islands induced early crack initiation at comparatively low strains due to increased stress near their vertical edges. The impact of island shape and gap on the crack formation in a Pt film was subsequently investigated. The gap between islands, oriented perpendicular to the loading direction, has minimal impact on crack number and density; the presence of Pt islands reduced the stress in the Pt film within the gap, thereby lowering the susceptibility of cracking in these areas. Variations in island shape and gap along loading direction alter the stress profile in the film between islands but did not significantly impact crack density. Crack density is believed to be primarily associated with pre-existing defects, with the formation of cracks serving as a stress relief mechanism that prevents further crack initiation. Our study sheds light on the impact of active islands on blanket film failure and offers practical recommendations to mitigate crack formation, which may contribute to the optimisation of flexible electronics design.
Analytical calculations of the tenth order QED radiative corrections to lepton anomalies within the Mellin–Barnes representation
Authors: Solovtsova O P , Lashkevich V I , Kaptari L P
Published: February 2024

We investigate the radiative QED corrections to the lepton (L = e, μ and τ) anomalous magnetic moment due to the contributions of diagrams with insertions of the photon vacuum polarisation operator consisting solely of four closed lepton (l = e, μ and τ) loops. Moreover, we focus on specific operators with two loops formed by leptons L of the same type as the external one, the other two formed by leptons ℓ different from L. The approach is essentially based on the employment of the Mellin–Barnes representation of the x-parametrization of the corresponding Feynman diagrams. This allows one to obtain, for the first time, exact analytical expressions for the radiative corrections of the tenth order w.r.t. the electromagnetic coupling constant e. Analytically, the radiative corrections are expressed in terms of the ratio r = m

ℓ
/m

L
of the internal to external lepton masses. The dependence on r is investigated numerically in the whole interval of r, 0 < r < ∞ . To make comparisons with earlier published results possible, our exact analytical expressions are expanded as r → 0 and r → ∞ and compared with the corresponding asymptotic expansions known in the literature.
Correlation between magnetic field and nuclear stopping in different rapidity segments during heavy ion collisions
Authors: Sharma Dhanpat , Kumar Suneel
Published: February 2024

The mid-rapidity zone is a region of crucial scientific interest during heavy ion collisions as it offers deep insight into the complex dynamics and properties of extremely dense nuclear matter. In the framework of the isospin-dependent quantum molecular dynamics model, the mid-rapidity zone (–0.6 ≤ Y

c.m./Y

beam
≤ 0.6) is segregated into three different regions to discover the intricate correlation between nuclear stopping (〈R

p
〉) and the magnetic field

eB

y

(
0
,
0
,
0
)

generated due to the nucleons from these rapidity segments. Moreover, study of the time and space evolution of

eB

y

(
0
,
0
,
0
)

has been carried out for all the three rapidity bins. The maximum magnetic field intensity

eB

y

(
0
,
0
,
0
)

max

is observed in the outwardmost region of the mid-rapidity zone due to less nuclear stopping and fewer nucleon–nucleon collisions. Additionally, a fruitful correlation has also been observed between eccentricity and nuclear stopping.
Asynchronous propagation of atomic force and excited electronic charge in GaAs under proton irradiation
Authors: Shi Wen-Hao , Deng Zun-Yi , Feng Hong-Jian
Published: February 2024

The studies for the interaction of energetic particles with matter have greatly contributed to the exploration of material properties under irradiation conditions, such as nuclear safety, medical physics and aerospace applications. In this work, we theoretically simulate the non-adiabatic process for GaAs upon proton irradiation using time-dependent density functional theory, and find that the radial propagation of force on atoms and the excitation of electron in GaAs are non-synchronous process. We calculated the electronic stopping power on proton with the velocity of 0.1–0.6 a.u., agreement with the previous empirical results. After further analyzing the force on atoms and the population of excited electrons, we find that under proton irradiation, the electrons around the host atoms at different distances from the proton trajectories are excited almost simultaneously, especially those regions with relatively high charge density. However, the distant atoms have a significant hysteresis in force, which occurs after the surrounding electrons are excited. In addition, hysteresis in force and electron excitation behavior at different positions are closely related to the velocity of proton. This non-synchronous propagation reveals the microscopic dynamic mechanism of energy deposition into the target material under ion irradiation.
Structural damage identification with output-only strain measurements and swarm intelligence algorithms: a comparative study
Authors: Zhang Guangcai , Hou Jiale , Feng Kun , Wan Chunfeng , Xie Liyu , Xue Songtao , Noori Mohammad , Ding Zhenghao
Published: February 2024

The identification of structural damage with the unavailability of input excitations is highly desired but challenging since structural dynamic responses are affected by the coupling effect of structural parameters and external excitations. To deal with this issue, in this paper, an output-only damage identification strategy based on swarm intelligence algorithms and correlation functions of strain responses is proposed to identify structures subjected to single or multiple unknown white noise excitations. In the proposed strategy, four different population-based optimization algorithms—particle swarm optimization, the butterfly optimization algorithm, the tree seed algorithm, and a micro search Jaya (MS-Jaya)—are employed and compared. The micro search mechanism is integrated into a basic Jaya algorithm to improve its computational efficiency and accuracy by eliminating some damage variables with small values for the identified best solution after several iterations. The objective function is established based on the proposed auto/cross-correlation function of strain responses and a penalty function. The effectiveness of the proposed method is verified with numerical studies on a simply supported beam structure and a steel grid benchmark structure under ambient excitation. In addition, the effect of the reference point, number of sensors, and arrangement of strain gauges on the performance of the proposed method are discussed in detail. The investigated results demonstrate that the proposed approach can accurately detect, locate, and quantify structural damage with limited sensors and 20% noise-polluted strain responses. In particular, the proposed MS-Jaya algorithm presents a more superior capacity in solving the optimization-based damage identification problem than the other three algorithms.
A lightweight multi-feature fusion vision transformer bearing fault diagnosis method with strong local sensing ability in complex environments
Authors: Li Sen , Zhao Xiaoqiang
Published: February 2024

Fault diagnosis of rolling bearings in complex environments is a difficult problem. First, the median filter can remove the noise in the vibration signals, however, it cannot adaptively adjust the filter weights according to the input signals. Second, the popular vision transformer (ViT) cannot extract local feature information under complex conditions and has a large number of parameters, which result in increased computational complexity. To solve these problems, a lightweight multi-feature fusion ViT bearing fault diagnosis method with strong local awareness in complex environments is proposed. Firstly, to learn the features and statistical distributions of the input signals, the gradient descent method is used to continuously and iteratively update the weights and filter the signals. Then, to better extract critical local fault information, a local sensing module is constructed using multi-scale wide convolutional neural network. Finally, an improved lightweight multi-feature fusion ViT is constructed to perform global feature extraction and fault identification. The results show that the proposed method has better noise reduction effect and feature extraction ability, and can accurately identify the fault types under the complex environments.
Atomic layer deposition for tuning the surface chemical composition of nickel iron phosphates for oxygen evolution reaction in alkaline electrolyzers
Authors: Blomme Ruben , Ramesh Rahul , Henderick Lowie , Minjauw Matthias , Vereecken Philippe , Adriaens Mieke , Detavernier Christophe , Dendooven Jolien
Published: February 2024

Transition metal phosphates are promising catalysts for the oxygen evolution reaction (OER) in alkaline medium. Herein, Fe-doped Ni phosphates are deposited using plasma-enhanced atomic layer deposition (PE-ALD) at 300 °C. A sequence of f Fe phosphate PE-ALD cycles and n Ni phosphate PE-ALD cycles is repeated x times. The Fe to Ni ratio can be controlled by the cycle ratio (f/n), while the film thickness can be controlled by the number of cycles (x times (n+f )). 30 nm films with an Fe/Ni ratio of ∼10% and ∼37%, respectively, are evaluated in 1.0 M KOH solution. Remarkably, a significant difference in OER activity is found when the order of the Ni and Fe phosphate PE-ALD cycles in the deposition sequence is reversed. A 20%–45% larger current density is obtained for catalysts grown with an Fe phosphate PE-ALD cycle at the end compared to the Ni phosphate-terminated flavour. We attribute this to a higher concentration of Fe centers on the surface, as a consequence of the specific PE-ALD approach. Secondly, increasing the thickness of the catalyst films up to 160 nm results in an increase of the OER current density and active surface area, suggesting that the as-deposited smooth and continuous films are converted into electrolyte-permeable structures during catalyst activation and operation. This work demonstrates the ability of PE-ALD to control both the surface and bulk composition of thin film electrocatalysts, offering valuable opportunities to understand their impact on performance.
Ratiometric fluorescence detection of dopamine based on copper nanoclusters and carbon dots
Authors: Meng Zhihan , Sun Shupei , Pu Ximing , Wang Juang , Liao Xiaoming , Huang Zhongbing , Deng Yi , Yin Guangfu
Published: February 2024

Nanoclusters for fluorescence detection are generally comprised of rare and expensive noble metals, and the nanoclusters based on more affordable transition metal have attracted increasing attention. This study designed a ratiometric fluorescent probe to detect dopamine (DA), an important neurotransmitter. With carbon dots encapsulated within silica (CDs@SiO2) as the reference, the emitted reference signal was almost unchanged due to the protection of inert silicon shell. Meanwhile, copper nanoclusters modified with 3-aminophenyl boronic acid (APBA-GSH-CuNCs) provided the sensing signal, in which the phenylboric acid could specifically recognize the cis-diol structure of DA, and caused the fluorescence quenching by photoinduced electron transfer. This dual emission ratiometric fluorescent probe exhibited high sensitivity and anti-interference, and was able to selectively responded to DA with a linear range of 0–1.4 mM, the detection limit of 5.6 nM, and the sensitivity of 815 mM−1. Furthermore, the probe successfully detected DA in human serum samples, yielding recoveries ranging from 92.5% to 102.7%. Overall, this study highlights the promising potential of this ratiometric probe for detecting DA.
Improvement of electrothermal and photothermal properties of ultra-thin graphite film on oxygen plasma-treated polyimide substrate
Authors: Ren Mengshuai , Mao Bo , Ding Pei , Niu Luyang , Yuan Zhi , Jia Xuan , Wang Zhihuan , Xu Kun , Wang Junqiao
Published: February 2024

Graphene and its derivatives are widely used in the field of energy conversion and management due to their excellent physical and chemical properties. In this paper, ultra-thin graphite film (GF) with thickness of 100–150 nm prepared by chemical vapor deposition was transferred to oxygen plasma-treated polyimide (PI) substrate as flexible heating film. The electrothermal and photothermal properties of GF on PI substrates with different treatment time were studied. The experimental results show that the PI substrate pretreated by oxygen plasma can change the surface morphology of GF, increase its electrical conductivity and light absorption capacity, and significantly improve the electrothermal and photothermal properties of GF heater. Under the low applied voltage of 5 V (power density of 0.81 W cm−2), the surface temperature of GF on 40 min plasma-treated PI substrate can rise to 250 °C, which is nearly 50 °C higher than that of GF on untreated PI substrate. When 100 nm thick commercial multilayer graphene film (MLG) is used, plasma-treated PI substrate can increase the electric heating temperature of MLG by 70 °C. In terms of photothermal performance, the surface temperature of GF on 50 min plasma-treated PI substrate can reach 73 °C under one Sun irradiation, which is 8 °C higher than that on untreated substrate. The experimental results are in good agreement with the simulation research. Our strategy has important implications for the development of efficient and energy-saving graphene/graphite-based heating films for advanced electrothermal and photothermal conversion devices.
SM-GRSNet: sparse mapping-based graph representation segmentation network for honeycomb lung lesion
Authors: Zhang Yuanrong , Feng Xiufang , Dong Yunyun , Chen Ying , Zhao Zian , Yang Bingqian , Chang Yunqing , Bai Yujie
Published: February 2024

Objective. Honeycomb lung is a rare but severe disease characterized by honeycomb-like imaging features and distinct radiological characteristics. Therefore, this study aims to develop a deep-learning model capable of segmenting honeycomb lung lesions from Computed Tomography (CT) scans to address the efficacy issue of honeycomb lung segmentation. Methods. This study proposes a sparse mapping-based graph representation segmentation network (SM-GRSNet). SM-GRSNet integrates an attention affinity mechanism to effectively filter redundant features at a coarse-grained region level. The attention encoder generated by this mechanism specifically focuses on the lesion area. Additionally, we introduce a graph representation module based on sparse links in SM-GRSNet. Subsequently, graph representation operations are performed on the sparse graph, yielding detailed lesion segmentation results. Finally, we construct a pyramid-structured cascaded decoder in SM-GRSNet, which combines features from the sparse link-based graph representation modules and attention encoders to generate the final segmentation mask. Results. Experimental results demonstrate that the proposed SM-GRSNet achieves state-of-the-art performance on a dataset comprising 7170 honeycomb lung CT images. Our model attains the highest IOU (87.62%), Dice(93.41%). Furthermore, our model also achieves the lowest HD95 (6.95) and ASD (2.47). Significance. The SM-GRSNet method proposed in this paper can be used for automatic segmentation of honeycomb lung CT images, which enhances the segmentation performance of Honeycomb lung lesions under small sample datasets. It will help doctors with early screening, accurate diagnosis, and customized treatment. This method maintains a high correlation and consistency between the automatic segmentation results and the expert manual segmentation results. Accurate automatic segmentation of the honeycomb lung lesion area is clinically important.
Multi-machine benchmark of the self-consistent 1D scrape-off layer model DIV1D from stagnation point to target with SOLPS-ITER
Authors: Derks G L , Westerhof E , van Berkel M , Jenneskens J H , Koenders J T W , Mijin S , Moulton D , Reimerdes H , Wu H
Published: February 2024

This paper extends a 1D dynamic physics-based model of the scrape-off layer (SOL) plasma, DIV1D, to include the core SOL and possibly a second target. The extended model is benchmarked on 1D mapped SOLPS-ITER simulations to find input settings for DIV1D that allow it to describe SOL plasmas from upstream to target—calibrating it on a scenario and device basis. The benchmark shows a quantitative match between DIV1D and 1D mapped SOLPS-ITER profiles for the heat flux, electron temperature, and electron density within roughly 50% on: (1) the Tokamak Configuration Variable (TCV) for a gas puff scan; (2) a single SOLPS-ITER simulation of the Upgraded Mega Ampere Spherical Tokamak; and (3) the Upgraded Axially Symmetric Divertor EXperiment in Garching Tokamak (AUG) for a simultaneous scan in heating power and gas puff. Once calibrated, DIV1D self-consistently describes dependencies of the SOL solution on core fluxes and external neutral gas densities for a density scan on TCV whereas a varying SOL width is used in DIV1D for AUG to match a simultaneous change in power and density. The ability to calibrate DIV1D on a scenario and device basis is enabled by accounting for cross field transport with an effective flux expansion factor and by allowing neutrals to be exchanged between SOL and adjacent domains.
Vibration control of giant electrorheological damper combining nonlinear fractional-order controller and extended state observer
Authors: Pu Huayan , Liu Jun , Wang Min , Ding Jiheng , Luo Jun , Sun Yi
Published: February 2024

As a typical smart material, giant electrorheological fluid (GERF) has a greater yield stress than electrorheological fluid for vibration isolation. However, as rheological material, the modeling precision is severely degraded by its innate rate-dependent hysteretic nonlinearity and uncertainty. In this paper, a novel control method is proposed, which requires little information about the damper based on GERF. The proposed method combines nonlinear fractional-order control (FC) and extended state observer (ESO) by constructing damper as a second-order disturbance-based structure to handle hysteretic nonlinearities, dynamic uncertainties and unknown disturbances. In contrast to the prevalent model-free control (MFC) that neglects hysteresis nonlinearity, the proposed control algorithm considers it as a general disturbance and eliminates it. In addition, compared with linear FC with complex fractional-order ESO, where the order needs to be known in advance, nonlinear FC has improved robustness for uncertain fractional-order systems only via pure ESO. Simulations and experimental results demonstrate that the nonlinear controller outperforms the linear counterpart and the proposed method exhibits superior control performance compared to the existing MFC, with an improvement of 26.9%.
Customized deformation behavior of morphing wing through reversibly assembled multi-stable metamaterials
Authors: Wang Chengyu , Wang Zhigang , Wang Huitian , Chen Zhuo , Tian Yuan , Yang Yu , Yin Sha
Published: February 2024

The geometry of multi-stable metamaterials, will change by the transition from one stable state to another. Shape morphing wings consisted of multi-stable metamaterials have capability to deform as desired, attributed to the programmable mechanical properties of architectured materials. In this study, to fabricate large-scale shape morphing structures, multi-stable unit cells with reversible connections were designed, printed and assembled. The mechanical properties and deformation capability were examined for multi-stable metamaterials with different geometrical parameters (e.g. width, thickness of beams). The deformation sequence for one assembled column consisting of identical multi-stable unit cells was found unpredictable, but could be tailored into a predictable manner by slightly adjusting beam geometry. To realize the customized deformation profile, the overall design domain of shape morphing structures was discretized into independent sub-regions. By enforcing deformation on sub-regions via the precise control of mechanical actuators that fixed with corresponding columns, the assembled shape morphing structures formed the targeted deformation. Also, the deformation feasibility was also demonstrated after incorporating voids or nondeformable functional elements within the assembled metamaterials platform. This study had provided practical solution for the design and fabrication of metamaterial-based shape morphing structures, and would shed light on future innovation of morphing aircraft.
Dynamics of oscillator populations with disorder in the coupling phase shifts
Authors: Pikovsky Arkady , Bagnoli Franco
Published: February 2024

We study populations of oscillators, all-to-all coupled by means of quenched disordered phase shifts. While there is no traditional synchronization transition with a nonvanishing Kuramoto order parameter, the system demonstrates a specific order as the coupling strength increases. This order is characterized by partial phase locking, which is put into evidence by the introduced novel correlation order parameter, which is shown to grow monotonically with the coupling strength, and via frequency entrainment by following concentration of the oscillators frequencies. Simulations with phase oscillators, Stuart–Landau oscillators, and chaotic Roessler oscillators demonstrate similar scaling of the correlation order parameter with the coupling and the system size and also similar behavior of the frequencies with maximal entrainment (at which the standard deviation of the frequencies is reduced by a factor close to four) at some finite coupling.
Hardware study and implementation of image encryption algorithm based on a hyperchaotic key generator
Authors: Amdouni Rim , Hajjaji Mohamed Ali , Mtibaa Abdellatif
Published: February 2024

In today’s interconnected world, digital data transmissions are an integral part of our communication systems. Connected objects are commonly used in digital life, however, they can be vulnerable to hacking and personal data theft due to inadequate security. To address the size and capability limitations of existing embedded devices, lightweight cryptography has been developed. This paper presents a hardware implementation of a lightweight cryptographic method using VHDL and FPGAs to secure digital information, specifically images. The proposed algorithm is a block cipher scheme that operates on blocks of 128-bit length and employs chaos based generator-based. The cryptosystem includes a whitening operation, random permutation, and key-dependent Substitution box. The proposed hardware implementation of the algorithm was validated using a Xilinx FPGA-Zynq platform and can secure different gray-scale images while maintaining low power usage, a high frequency of 160.6098 MHz, and high throughput of 11314.917 Mbps. The cryptosystem is shown to be effective against statistical and differential attacks, and key sequences are tested using the NIST SP 800–22 test suite. The algorithm’s robustness with respect to Shannon’s theory and Chaos is discussed, emphasizing its high level of security and performance.
Intrinsically low lattice thermal conductivity and thermoelectric performance of 2D Cu2Te
Authors: Bölen E , Deligoz E , Ozisik H
Published: February 2024

In this study, we employed density functional theory to investigate the structural, mechanical, dynamical, electronic, and thermal transport properties of 2D Cu2Te in the hexagonal P6/mm structure. Our results demonstrate that this structure is both mechanically and dynamically stable, and has a direct band gap, indicating its potential as a semiconductor. The high Grüneisen parameter value of 2D Cu2Te resulted in a lower lattice thermal conductivity compared to its bulk counterpart due to increased phonon scattering in the 2D structure. Furthermore, we observed that the Seebeck coefficient in 2D Cu2Te is higher in the p-type region, while the electrical conductivity is higher in the n-type region at lower temperatures. Two different approaches were used to calculate the lattice thermal conductivity, and it was found that the thermal conductivity decreases with dimension reduction in Cu2Te. Additionally, ultralow thermal conductivity was observed. Moreover, the lattice thermal conductivity plays a dominant role in the thermoelectric performance. The maximum ZT value for 2D Cu2Te was obtained as 1.28 at 700 K. Overall, our results suggest that 2D Cu2Te is a potential new candidate for high thermoelectric performance.