bluuebunny/crossref_metadata_2025 huggingface dataset:
A Gauss–Newton method for iterative optimization of memory kernels for generalized Langevin thermostats in coarse-grained molecular dynamics simulations
Authors: Klippenstein Viktor , Wolf Niklas , van der Vegt Nico F. A.
Published: May 2024

In molecular dynamics simulations, dynamically consistent coarse-grained (CG) models commonly use stochastic thermostats to model friction and fluctuations that are lost in a CG description. While Markovian, i.e., time-local, formulations of such thermostats allow for an accurate representation of diffusivities/long-time dynamics, a correct description of the dynamics on all time scales generally requires non-Markovian, i.e., non-time-local, thermostats. These thermostats typically take the form of a Generalized Langevin Equation (GLE) determined by a memory kernel. In this work, we use a Markovian embedded formulation of a position-independent GLE thermostat acting independently on each CG degree of freedom. Extracting the memory kernel of this CG model from atomistic reference data requires several approximations. Therefore, this task is best understood as an inverse problem. While our recently proposed approximate Newton scheme allows for the iterative optimization of memory kernels (IOMK), Markovian embedding remained potentially error-prone and computationally expensive. In this work, we present an IOMK-Gauss–Newton scheme (IOMK-GN) based on IOMK that allows for the direct parameterization of a Markovian embedded model.
Flow physics in a micro turbojet engine inter-shaft fuel supply system
Authors: Wang Zhixun , Liu Kehui , Wang Zhuo , Gao Feng , Sun Xiaofeng
Published: May 2024

Inter-shaft fuel supply systems (ISFSSs) consisting of a shaft annulus and a fuel slinger are usually used in micro turbojet engines to pump the fuel to the combustor, aiming at reducing engine's size and weight. Differing from the configuration with stationary fuel pipework, the fast-rotating shaft in the annulus would induce significant drag jeopardizing the fuel supply during engine acceleration. This study investigates the flow physics inside a micro turbojet engine ISFSS. Air–fuel two-phase flow is found in the slinger cavity and the shaft annulus, with main gas path air ingress into the ISFSS under disk pumping of the slinger, and the ingress is enhanced by introducing blades on the slinger disk. Results show that the axial flow drag in the shaft annulus is reduced as air being ingested in. Further investigation indicates that the best supplied fuel volume fraction is 0.8, and this can reduce the axial drag in the shaft annulus by ∼63%, compared with the single-phase fuel flow. Therefore, two-phase air–fuel mixture is proposed for the ISFSS drag reduction.
Tunable and enhanced thermoelectric properties in transition metal–terpyridine complex based molecular devices
Authors: He Xia , Cao Xuan-Hao , Ding Zhong-Ke , Luo Nan-Nan , Zeng Jiang , Tang Li-Ming , Chen Ke-Qiu
Published: May 2024

Using the density function theory in combination with the non-equilibrium Green’s function method, the thermoelectric properties of molecular devices based on transition metal–terpyridine complexes are investigated. The results show that their thermoelectric properties can be significantly improved by changing the transition metal and the twist angle of the complex molecule, which is caused by shifting the molecular energy levels, resulting in increased coupling strength between the electrodes and the central molecule. The ZT value of the Ru-containing molecular device can reach up to 0.9 at room temperature, which is three orders of magnitude greater than that of the graphene nanoribbons of the same width. In addition, its thermoelectric performance can be further promoted by suppressing phonon thermal conductance through enhanced isotope scattering. The ZT value of doped devices can reach up to 1.0 in the range of 300–700 K. This work may help in the design and fabrication of transition metal-containing twistable molecular devices and provide effective methods to regulate their thermoelectric properties.
Extracting the electronic structure of light elements in bulk materials through a Compton scattering method in the readily accessible hard x-ray regime
Authors: Kothalawala Veenavee Nipunika , Guruswamy Tejas , Quaranta Orlando , Patel Umeshkumar Manibhai , Gades Lisa , Taddei Keith , Yakovenko Andrey , Zheng Meiying , Morgan Kelsey , Weber Joel , Yan Daikang , Swetz Daniel , Makkonen Ilja , Yeddu Hemantha Kumar , Bansil Arun , Ruett Uta , Miceli Antonino , Nokelainen Johannes , Barbiellini Bernardo
Published: May 2024

Our Compton profile measurements of Ti and TiH2 using readily available hard X-ray radiation at 27.5 keV, detected by both a Hitachi Vortex silicon-drift detector and a high-resolution superconducting transition-edge sensor array, are found to be in excellent accord with state-of-the-art density functional theory based calculations. The spherically averaged difference between the Compton profiles of TiH2 and Ti is well described by an inverted parabola, supporting an itinerant behavior of the electron gas screening the protons in the Ti matrix. Our experimental approach, validated by two different detectors, extends the applicability of Compton scattering technique to the readily accessible hard x-ray regime (below 30 keV). Our study suggests possibilities for experiments at low-flux bending magnet synchrotron beamlines and paves the way for the development of tabletop Compton experiments with x-ray tubes.
Solar lasers: Why not?
Authors: Küblböck Michael , Will Jonathan , Fattahi Hanieh
Published: May 2024

In this paper, we investigate the role of solar laser technology as a pivotal element in advancing sustainable and renewable energy. We begin by examining its wide-ranging applications across diverse fields, including remote communication, energy storage through magnesium production, and space exploration and communication. We address the current challenges faced by solar laser technology, which include the necessity for miniaturization, operation at natural sunlight intensity without the need for concentrated power, and efficient energy conversion. These improvements are essential to elevate their operational performance, beam quality, and cost-effectiveness. The promising prospects of space-based solar-pumped lasers and their potential role in magnesium generation for a sustainable energy future highlight some of the vast application opportunities that this novel technology could offer.
Study of intermittent jets and free-surface-pressurized flow in large hydropower tailrace tunnel
Authors: Guo Junxun , Zhou Daqing , Wang Haobo
Published: May 2024

The tailrace tunnel system, as a core component of hydroelectric power stations, directly influences the stability and efficiency of the power generation process. Transient conditions often lead to the occurrence of complex unsteady flow phenomena in the tailrace tunnel. In this study, numerical methods integrating open channel flow, multiphase flow, and compressible models were combined to conduct hydraulic analysis of the tailrace system in large hydroelectric power stations. Under specific conditions, periodic jet phenomena were observed, corroborating field observations. The research revealed that the proximity of downstream water levels to the crest level of the tailrace outlet is a prerequisite for the periodic jetting phenomenon, with a sudden rise in water level serving as a triggering condition. Although the surge shaft effectively mitigates wave action, it fails to entirely eliminate the influence of pressure pulsations, resulting in a 23.2% increase in pressure pulsation amplitude in the turbine area. However, the efficiency of the turbine unit is hardly affected; only a slight loss of energy occurs due to the increase in local turbulent entropy production, deemed inconsequential for the overall system. This study aims to investigate the complex response of tailrace tunnel systems in hydroelectric power generation amidst abrupt changes in downstream river, providing crucial insights for the engineering design and operation of large-scale power stations.
Active feedback control on acoustic radiation of metastructure shell with low-frequency and broadband characteristics
Authors: Guo Yi-Le , Wang Yi-Ze
Published: May 2024

Due to the tunable characteristics of elastic waves, the vibroacoustic coupling behavior of a mechanical metastructure is a hot topic of underwater vehicles. In this work, a metastructure shell with active feedback control is presented and fabricated. The dynamic effective density and sound pressure level are derived to find the influences of acceleration and displacement feedback control. Different from a single cylinder, a double cylinder structure has both in-phase and anti-phase modes. Numerical results are obtained by Fourier transform and harmonic series expansion. With the introduction of an active feedback control system, the reduction of acoustic radiation shows low-frequency and broadband characteristics. In addition, finite element simulation is applied to support numerical results and present vibroacoustic characteristics. Finally, an experiment is performed in the anechoic chamber to illustrate the quiet metastructure shell, which can be applied to new designs of underwater vehicles.
The ethnographic museum as a sensitive translation
Authors: Spiessens Anneleen , van Doorslaer Luc
Published: May 2024

This article analyzes the recently renewed, permanent exhibition of the Royal Museum for Central Africa
(AfricaMuseum) in Tervuren, Belgium. The museum is seen as a translational space, considering the parallels between, on the one
hand, curatorial strategies to represent cultural otherness and, on the other, processes of cultural and interlingual translation
(Sturge 2007). We draw on an interdisciplinary mindset of translation as change and
choice, as a multimodal and multimedial activity, and as an inevitably meaning-transforming process. Pressured to keep pace with
the rapidly evolving public debate on decolonization, the curators-translators of the AfricaMuseum are aware that they are dealing
with “sensitive texts” (Simms 1997) and have, accordingly, adopted a set of strategies
to reduce perceived “translation risks” (Pym and Matsushita 2018). The article explores
these strategies at three levels of translation operating in the museum: cultural, intersemiotic, and interlingual. In particular,
we reveal the inherent tensions in the current display by discussing scenographic interventions that undermine the decolonization
efforts in a number of galleries. These tensions are conceptualized as incomplete or incoherent forms of translation and
illustrate the “work in progress” in the AfricaMuseum.
Gravity with torsion as deformed BF theory
*
Authors: Cattaneo Alberto S , Menger Leon , Schiavina Michele
Published: May 2024

We study a family of (possibly non topological) deformations of BF theory for the Lie algebra obtained by quadratic extension of

so

(
3
,
1
)

by an orthogonal module. The resulting theory, called quadratically extended General Relativity (qeGR), is shown to be classically equivalent to certain models of gravity with dynamical torsion. The classical equivalence is shown to promote to a stronger notion of equivalence within the Batalin–Vilkovisky formalism. In particular, both Palatini–Cartan gravity and a deformation thereof by a dynamical torsion term, called (quadratic) generalised Holst theory, are recovered from the standard Batalin–Vilkovisky formulation of qeGR by elimination of generalised auxiliary fields.
Optimal shielding for Einstein gravity
Authors: Le Floch Bruno , LeFloch Philippe G
Published: May 2024

To construct asymptotically-Euclidean Einstein’s initial data sets, we introduce the localized seed-to-solution method, which projects from approximate to exact solutions of the Einstein constraints. The method enables us to glue together initial data sets in multiple asymptotically-conical regions, and in particular construct data sets that exhibit the gravity shielding phenomenon, specifically that are localized in a cone and exactly Euclidean outside of it. We achieve optimal shielding in the sense that the metric and extrinsic curvature are controlled at a super-harmonic rate, regardless of how slowly they decay (even beyond the standard Arnowitt–Deser–Misner (ADM) formalism), and the gluing domain can be a collection of arbitrarily narrow nested cones. We also uncover several notions of independent interest: silhouette functions, localized ADM modulator, and relative energy-momentum vector. An axisymmetric example is provided numerically.
Automated evaluation of environmental coupling for Advanced LIGO gravitational wave detections
Authors: Helmling-Cornell A F , Nguyen P , Schofield R M S , Frey R
Published: May 2024

The extreme sensitivity required for direct observation of gravitational waves by the Advanced LIGO detectors means that environmental noise is increasingly likely to contaminate Advanced LIGO gravitational wave signals if left unaddressed. Consequently, environmental monitoring efforts have been undertaken and novel noise mitigation techniques have been developed which have reduced environmental coupling and made it possible to analyze environmental artifacts with potential to affect the 90 gravitational wave events detected from 2015–2020 by the Advanced LIGO detectors. So far, there is no evidence for environmental contamination in gravitational wave detections. However, automated, rapid ways to monitor and assess the degree of environmental coupling between gravitational wave detectors and their surroundings are needed as the rate of detections continues to increase. We introduce a computational tool, PEMcheck, for quantifying the degree of environmental coupling present in gravitational wave signals using data from the extant collection of environmental monitoring sensors at each detector. We study its performance when applied to 79 gravitational waves detected in LIGO’s third observing run and test its performance in the case of extreme environmental contamination of gravitational wave data. We find that PEMcheck’s automated analysis identifies only a small number of gravitational waves that merit further study by environmental noise experts due to possible contamination, a substantial improvement over the manual vetting that occurred for every gravitational wave candidate in the first two observing runs. Building on a first attempt at automating environmental coupling assessments used in the third observing run, this tool represents an improvement in accuracy and interpretability of coupling assessments, reducing the time needed to validate gravitational wave candidates. With the validation provided herein; PEMcheck will play a critical role in event validation during LIGO’s fourth observing run as an integral part of the data quality report produced for each gravitational wave candidate.
Negative magnetization and magnetic ordering of rare earth and transition metal sublattices in NdFe0.5Cr0.5O3
Authors: Kanthal S , Banerjee A , Chatterjee S , Yanda P , Sundaresan A , Khalyavin D D , Orlandi F , Saha-Dasgupta T , Bandyopadhyay S
Published: May 2024

We investigate the effect of alloying at the 3d transition metal site of a rare-earth-transition metal oxide, by considering NdFe0.5Cr0.5O3 mixed perovskite with two equal and random distribution of 3d ions, Cr and Fe, interacting with an early 4f rare earth ion, Nd. Employing temperature- and field- dependent magnetization measurements, temperature-dependent x-ray diffraction, neutron powder diffraction, and Raman spectroscopy, we characterize its structural and magnetic properties. Our study reveals bipolar magnetic switching (arising from negative magnetization) and magnetocaloric effect which underline the potential of the studied mixed perovskite in device application. The neutron diffraction study shows the absence of spin reorientation transition over the entire temperature range of 1.5–320 K, although both parent compounds exhibit spin orientation transition. We discuss the microscopic origin of this curious behavior. The neutron diffraction results also reveal the ordering of Nd spins at an unusually high temperature of about 40 K, which is corroborated by Raman measurements.
Effective model and electron correlations in trilayer nickelate superconductor La4Ni3O10
Authors: Tian Peng-Fei , Ma Hao-Tian , Ming Xing , Zheng Xiao-Jun , Li Huan
Published: May 2024

Recently, signatures of superconductivity with critical temperature from 20 to 30 K have been reported in pressured trilayer nickelate La4Ni3O10 through a pressure-induced structure transition. Here we explore the evolution of electronic structures and electronic correlations in different phases of La4Ni3O10 under corresponding pressure regions, by using density functional theory (DFT) combined with dynamical mean-field theory (DMFT). Similar to bilayer superconductor La3Ni2O7, the electronic bands in superconducting La4Ni3O10 are dominated by Ni-3

d

x
2

−

y
2

and 3

d

z
2

orbits near the Fermi level, in contrast, the inner Ni–O plane in La4Ni3O10 generates a doublet hole-pocket Fermi surfaces around the Brillouin-zone corner, meanwhile one branch of the Ni-

3

d

z
2

bands is pushed very close above the Fermi level, which can induce an electron pocket through small electron doping. The DFT+DMFT simulations suggest that the electronic correlations only give minor modification to the Fermi surfaces, meanwhile the Ni-

3

d

z
2

and 3

d

x
2

−

y
2

states on outer Ni–O layers have considerable greater mass enhancements than on the inner layer. The sensitiveness of electronic structure under doping and unique layer dependence of correlation suggest a distinct superconducting mechanism with respect to bilayer La3Ni2O7. Based on the DFT and DFT+DMFT simulations, we eventually derive a trilayer effective tight-binding model, which can produce rather precise electronic bands and Fermi surfaces, hence can serve as an appropriate model to further study the superconducting mechanism and paring symmetry in trilayer La4Ni3O10.
Cross-domain fault diagnosis network based on attributes and features transfer with dual classifier under limited and unbalanced datasets
Authors: Song Shanshan , Zhang Shuqing , Liu Haitao , Wu Xiang
Published: May 2024

Deep learning (DL)-based methods have demonstrated significant success in fault diagnosis owing to their robust feature extraction and non-linear fitting capabilities. Meanwhile, their remarkable performance is accompanied by constant operating conditions and sufficient monitoring data. However, in real engineering environments, variable working conditions or limited and unbalanced data are common, which can widen the gap between fault diagnosis methods and real industrial applications. In this paper, we proposed a cross-domain fault diagnosis network based on a dual classifier (CFDNet) with input being limited and unbalanced data to learn attributes and features for unsupervised domain adaptation. We found that the diagnostic performance is commonly bounded by the underlying knowledge, especially feature extraction from original data. Therefore, we designed a new feature encoder with features and relationships, i.e. using a convolutional neural network and graph convolutional network, which improves extraction efficiency while retaining valuable information. Then, we discovered that enforced feature transfer can lead to negative transfer. To mitigate this, we present a feature and attribute transfer framework, which not only achieves features transfer but also enables attributes transfer. Furthermore, it was noted that limited and unbalanced datasets can introduce label bias and lead to biased model training. Hence, we designed dual classifiers to improve the probability of high-confidence final prediction by synthesizing diagnostic results. Comprehensive experiments conducted on three case studies demonstrate the effectiveness and superiority of our method for cross-domain fault diagnosis under limited and unbalanced datasets, which outperforms state-of-the-art methods in this study.
A fast point cloud registration method based on spatial relations and features
Authors: Liao Zhuhua , Zhang Hui , Zhao Yijiang , Liu Yizhi , Yang Jiyuan
Published: May 2024

Point cloud registration plays a crucial role in mobile robot localization, map building and three-dimensional (3D) model reconstruction. However, it remains challenged by issues such as compromised accuracy and sluggish efficiency, posing significant obstacles in achieving precise and timely alignments. Therefore, we propose a lightweight and fast point cloud registration method. Firstly, we mesh the 3D point cloud, compared with the traditional gridded point cloud method, it achieves initial point cloud registration by preserving the curvature characteristics of the internal point cloud, and utilizing the spatial relationship between grid cells and the quantitative relationship between the internal point cloud. Moreover, we adopt an iterative nearest point based on KD-Tree to realize the fine registration. So, our method does not necessitate intricate feature analysis and data training, and is resilient to similar transformations, non-uniform densities and noise. Finally, we conduct point cloud registration experiments using multiple publicly available point cloud datasets and compare them with several point cloud registration methods. The results demonstrate it is able to accomplish the point cloud registration quickly and exhibit high accuracy. More importantly, it maintains its efficacy and robustness even in the presence of noisy and defective point clouds.
Dynamic simulation-assisted Gaussian mixture alignment approach for fault diagnosis of rotation machinery under small samples
Authors: Yu Shubo , Liu Zhansheng , Zhang Gaorong , Wang Saibo
Published: May 2024

Obtaining a substantial number of actual samples for rotating machinery in an industrial setting can be challenging, particularly when faulty samples are acquired under hazardous working conditions. The issue of insufficient samples hinders the effective training of reliable fault diagnosis models, impeding the industrial implementation of advanced intelligent methods. This study proposes an innovative dynamic simulation-assisted Gaussian mixture alignment model (DSGMA) to address the challenge of applying fault diagnosis technologies, with its performance mined by advanced transfer algorithms. Specifically, we establish a fault dynamics model for rotating machinery and acquire a substantial amount of simulated data as the source domain to facilitate the training of the deep neural network model. Subsequently, we propose a Gaussian mixture-guided domain alignment approach that assigns a domain-independent Gaussian distribution to each category as prior knowledge, with the parameters calculated using limited actual samples. Diagnostic knowledge is transferred from the source domain to the target domain by minimizing the Kullback–Leibler divergence between the features of the simulated samples and the Gaussian mixture priors. Furthermore, the DSGMA model incorporates Gaussian clustering loss to augment the clustering capability of samples belonging to the same category from real devices and enhances the computational stability of the parameters in the Gaussian mixture model. The efficacy of the DSGMA method is validated using three publicly available datasets and compared against five widely adopted methods. The experimental findings illustrate that DSGMA exhibits superior diagnostic and robust capabilities, facilitating efficient fault diagnosis under scenarios of small samples.
Enhanced low-temperature resistance of lithium-ion batteries based on methyl propionate-fluorinated ethylene carbonate electrolyte
Authors: Xiang Zhengping , Wang Liying , Yang Xijia , Yang Yue , Qu Ying , Gao Yang , Li Xuesong , Lü Wei
Published: May 2024

Low temperature has been a major challenge for lithium-ion batteries to maintain satisfied electrochemical performance, as it leads to poor rechargeability and low capacity retention. Traditional carbonate solvents, vinyl carbonate and dimethyl carbonate are indispensable components of commercial electrolytes. However, the higher melting point of these carbonate solvents causes their electrical conductivity to be easily reduced when temperatures drop below zero, limiting their ability to facilitate lithium ion transport. In this work, we demonstrate that the use of methyl propionate (MP) carboxylate and fluorocarbonate vinyl (FEC) electrolytes can overcome the limitations of low temperature cycling. Compared with carbonate electrolyte, MP has the characteristics of low melting point, low viscosity and low binding energy with Li+, which is crucial to improve the low temperature performance of the battery, while FEC is an effective component to inhibit the side reaction between MP and lithium metal. The carefully formulated MP-based electrolyte can generate a solid electrolyte interface with low resistance and rich in inorganic substances, which is conducive to the smooth diffusion of Li+, allowing the battery to successfully cycle at a high rate of 0.5 C at −20 °C, and giving it a reversible capacity retention rate of 65.3% at −40 oC. This work designs a promising advanced electrolyte and holds the potential to overcome limitations of lithium-ion batteries in harsh conditions.
Improved high voltage operation of amorphous In–Ga–Zn–O thin film transistor by carrier density enhancement
Authors: Ju Hyoungbeen , Bang Jiyoung , Sun Hyeonjeong , Lee Yeonghun , Kim Sangduk , Choi Seungmin , Noh Youngsoo , Kim Hyo Won , Choi Eunsuk , Jeong Jae Kyeong , Lee Seung-Beck
Published: May 2024

We report on improved high voltage operation of amorphous-In–Ga–Zn–O (a-IGZO) thin film transistors (TFTs) by increasing carrier density and distributing the high bias field over the length of the device which utilizes an off-set drain structure. By decreasing the O2 partial pressure during sputter deposition of IGZO, the channel carrier density of the high voltage a-IGZO TFT (HiVIT) was increased to ∼1018 cm−3. Which reduced channel resistance and therefore the voltage drop in the ungated offset region during the on-state. To further decrease the electric field in the offset region, we applied Ta capping and subsequent oxidation to locally increase the oxygen vacancy levels in the offset region thereby increasing local carrier density. The reduction of the drain field in the offset region from 1.90 V μm−1 to 1.46 V μm−1 at 200 V drain voltage, significantly improved the operational stability of the device by reducing high field degradation. At an extreme drain voltage of 500 V, the device showed an off-state current of ∼10−11 A and on-state current of ∼1.59 mA demonstrating that with further enhancements the HiVIT may be applicable to thin-film form, low leakage, high voltage control applications.
Wetting behavior of stainless-steel surface with zinc oxide nanorod coatings: modulations in nanorod alignment through atomic layer deposition
Authors: Kim Kyungmin , Hong Minpyo , Song Yongnam
Published: May 2024

This study investigated the hydrophobic-hydrophilic characteristics of zinc oxide (ZnO) nanorod coatings for potential biomedical applications. We examined the effects of different alignments of ZnO nanorods on the wetting and mechanical characteristics of the coatings. ZnO seed layers were prepared on stainless-steel plates using atomic layer deposition (ALD) at five different temperatures ranging from 50 to 250 °C. The ZnO nanorod coatings were then deposited on these seed layers through chemical bath deposition. The polycrystalline structure of the seed layers and the morphology of the nanorods were analyzed using grazing incidence angle x-ray diffraction, transmission electron microscopy, and scanning electron microscopy. Mechanical and wetting properties of the nanorod coatings were examined using nanoindentation and water-droplet tests. The seed layers produced at 50 and 250 °C showed stronger (0 0 2) peaks than the other layers. ZnO nanorods on these seed layers exhibited greater vertical orientation and lower water contact angles indicating a more hydrophilic surface. Additionally, vertically oriented nanorod coatings demonstrated greater elastic modulus and hardness than those of oblique nanorods. Our findings indicate that ALD technology can be used to control the spatial arrangement of ZnO nanorods and optimize the hydrophobic-hydrophilic and mechanical properties of coating surfaces.
Improving resonant ice protection systems with substrate optimization
Authors: Rafik Younes , Palanque Valerian , Budinger Marc , Pommier-Budinger Valerie , Olivier Philippe
Published: May 2024

Electro-mechanical de-icing systems are low-energy ice protection solutions based on ice fracture mechanisms. This article focuses on resonant electro-mechanical de-icing systems that actuate modes of flexion, which require low energy compared to extension modes. However, fracture propagation limits are encountered when using such flexural modes, preventing the ice from being completely detached from the substrate. This study demonstrates the feasibility of extending the ice detachment area by optimizing the thickness of the substrate. First, the interest and the limits of flexural resonant modes are discussed. Then the de-icing of a simple metallic beam in free conditions using a flexural mode is improved owing to the parametric optimization of the substrate thickness. The optimization is verified by tests on aluminum prototypes. The optimization results are then extended to a clamped composite plate and then to a NACA profile, showing interest in the approach to fully de-ice structures with modes of flexion, even in the case of complex geometries. With this last example, the study also demonstrates the feasibility of electro-mechanical ice protection systems for carbon fiber reinforced Polymer composite structures.
Modeling phase separation and composition patterning in FeCrAl alloys at neutron irradiation
Authors: Kharchenko D O , Kharchenko V O , Qin Jiantao , Wu Lu , Lysenko B O , Dvornichenko A V
Published: May 2024

Possible scenarios of the microstructural evolution of FeCrAl alloys under neutron irradiation are studied by using the phase-field method. The exploited approach is generalized by considering ballistic mixing of atoms, spatial rearrangement of point defects, and dynamics of their sinks (dislocation loops), self-consistently. Stability diagrams manifesting domains of main control parameters (irradiation temperature, damage rate, atomic relocation distance) governing precipitation are obtained. It is shown that depending on irradiation conditions a precipitation of the Cr-rich

α
′

-phase proceeds by either phase decomposition or composition patterning mechanism. Statistical analysis of precipitation kinetics is provided by studying precipitate number density, mean precipitate size and Chromium content in

α
′

-phase for a model alloy Fe-30%Cr-5%Al. A locality of point defects distribution with high concentration and dislocation loops growth are discussed. The hardening change is estimated for two possible scenarios of precipitation. Obtained results are verified with experimental observations. This study provides a deep insight into details of microstructural transformation in FeCrAl alloys during neutron irradiation.
Polarization-independent tunable multi-band terahertz absorber based on graphene structure to design the ultra-high sensitive biosensors
Authors: Rafighirani Yousef , Javidan Javad , Heidarzadeh Hamid
Published: May 2024

In this paper, we investigated the heterogeneous structure of a multi-band perfect absorber based on graphene in the terahertz range, benefiting from polarization independence. The proposed structure comprises three layers: copper, silicon dioxide, and an inhomogeneous graphene structure with an analyte. By altering the sub-layers dimensions and the graphene slices' geometric shape, we can modify the number of bands, quality, and absorption levels. Additionally, adjusting the chemical potential of graphene enables the customization of absorption frequencies as needed. The application of this structure in biological sensors extends to the detection of proteins, viruses, and cancer cells, as well as filtering telecommunication waves and imaging. Through geometrically shaping the graphene cuts at frequencies of 4.89 THz, 9.14 THz, and 10.76 THz, absorption values of 99.54%, 99.64%, and 98.3% have been achieved, respectively. Introducing the analyte to the biosensor structure causes a shift in absorption frequency values due to varying refractive index values in different materials. This property has been utilized for biosensor design. Within the refractive index range of biological analytes (e.g., 1.3), the first band achieved a sensitivity value of 2700 GHz/RIU and FoM = 13.08, while the second band achieved a sensitivity value of 2200 GHz/RIU and FoM = 14.02. An important characteristic of this structure is its insensitivity to polarization. Simulations were conducted using Computer Simulation Technology (CST) Microwave Studio Suite 2023.
Relativistic energies for the q-deformed Scarf potential with Feynman path integrals formulation
Authors: Diaf Ahmed , Hachama Mohammed
Published: May 2024

In this paper, the Dirac equation with the q-deformed Scarf potential for spin symmetry is solved for an arbitrary spin-orbit quantum number κ, in the presence of Coulomb-like potential tensor. Using the Feynman path integral formalism and the Pekeris approximation of the centrifugal term, we obtain the bound state energy eigenvalues and the associated spinor of the Dirac particle. Furthermore, this method is used to determine the spectrum of two diatomic molecules Li
2(61Π
u
) and KRb(B
−1Π). The obtained results are compared to the experimental and numerical ones.
Controlling vertical phase separation and crystallization via solvent synergy strategy to empower layer-by-layer processed organic solar cells
Authors: Li Hengyue , Yang Yu , Bai Xue , Zha Wusong , Chen Haopeng , Yang Yingguo , Lu Guanghao , Luo Qun , Ma Chang-Qi , Yang Junliang
Published: May 2024

The novel sequential layer-by-layer (LbL) processed organic solar cells (OSCs) have attracted continuous attention due to their advantages of ideal vertical phase separation, efficient charge transport and collection, and potentiality for large-scale production from laboratory to factory. Herein, a solvent synergy strategy is put forward to control morphology, crystallization and vertical phase distribution of blend films, which means the donor PM6 and acceptor Y6 treated by high/low boiling point solvents are fabricated using LbL solution process, respectively. Based on device with a configuration of ITO/ZnO/PM6:Y6/MoO3/Ag, OSCs derived from the solvent synergy strategy can obtain a remarkable power conversion efficiency (PCE) up to 15.03%, which is comparable to that of the bulk heterojunction devices prepared by conventional one-step solution method. This impressive result provides an insightful understanding of phase segregation and crystalllization in LbL processed OSCs assisted by the solvent synergy strategy. It lays the foundation for fabrication and optimization of high-performance, large-area OSCs in industrial production.
Sub-GeV millicharge dark matter from the U(1)
X
hidden sector
Authors: Feng Wan-Zhe , Zhang Zi-Hui , Zhang Kai-Yu
Published: May 2024

We conduct a comprehensive study on the sub-GeV millicharge dark matter
produced through the freeze-in mechanism.
We discuss in general the mixing mechanism,
encompassing both kinetic mixing and mass mixing,
between the U(1)
X
hidden sector and the standard model,
which can generate millicharge carried by the dark fermions from the hidden sector.
We discuss in depth how such millicharge is generated,
and clarify several misunderstandings regarding this subject in the literature.
Without employing an effective field theory approach,
where the photon field directly mixed with the additional U(1),
we analyze a general renormalizable model and
investigate the complete evolution of the hidden sector particles.
Due to the substantial self-interactions among hidden sector particles,
the evolution of the hidden sector temperature plays a crucial role,
which is addressed concurrently with the number densities of hidden sector particles
by solving a set of coupled Boltzmann equations.
We thoroughly examine eight benchmark models from six distinct cases.
Some of our key findings from the analysis of these benchmark models may be generalizable
and applicable to broader freeze-in scenarios.
We also explore the possibility that the 𝒪(keV) U(1)
X
dark photon is a viable dark matter candidate,
even though it can contribute at most ∼ 5% to the total observed dark matter relic density.
BAO cosmology in non-spatially flat background geometry from BOSS+eBOSS and lessons for future surveys
Authors: Sanz-Wuhl Santiago , Gil-Marín Héctor , Cuesta Antonio J. , Verde Licia
Published: May 2024

We study the impact of the assumption of a non-flat fiducial cosmology on the measurement, analysis and interpretation of BAO distance variables, along and across the line-of-sight. The assumption about cosmology enters in the choice of the base template, as well as on the transformation of tracer's redshifts into distances (the catalog cosmology): here we focus on the curvature assumption, separately and jointly, on both. We employ BOSS and eBOSS publicly available data and show that for the statistical precision of this data set, distance measures and thus cosmological inference are robust to assumptions about curvature both of the template and the catalog. Thus the usual assumptions of flat fiducial cosmologies (but also assumptions of non-flat cosmologies) do not produce any detectable systematic effects. For forthcoming large-volume surveys, however, small but appreciable residual systematic shifts can be generated which may require some care. These are mostly driven by the choice of catalog cosmology if it is significantly different from true cosmology. In particular, the catalog (and template) cosmology should be chosen, possibly iteratively, in such a way that the recovered BAO scaling variables are sufficiently close to unity. At this level of precision, however, other previously overlooked effects become relevant, such as a mismatch between the sound horizon as seen in the BAO and the actual sound horizon in the early Universe. If unaccounted for, such effect may be misinterpreted as cosmological and thus bias the curvature (and cosmology) constraints. We present best practices to avoid this.
Quantitative analysis of laser-generated ultrasonic wave characteristics and their correlation with grain size in polycrystalline materials
Authors: Xu 徐 Zhaowen 兆文 , Bai 白 Xue 雪 , Ma 马 Jian 健 , Wan 万 Zhuangzhuang 壮壮 , Wang 王 Chaoqun 超群
Published: May 2024

Quantitative relationship between nanosecond pulsed laser parameters and the characteristics of laser-generated ultrasonic waves in polycrystalline materials was evaluated. The high energy of the pulsed laser with a large irradiation spot simultaneously generated ultrasonic longitudinal and shear waves at the epicenter under the slight ablation regime. An optimized denoising technique based on wavelet thresholding and variational mode decomposition was applied to reduce noise in shear waves with a low signal-to-noise ratio. An approach for characterizing grain size was proposed using spectral central frequency ratio (SCFR) based on time-frequency analysis. The results demonstrate that the generation regime of ultrasonic waves is not solely determined by the laser power density; even at high power densities, a high energy with a large spot can generate an ultrasonic waveform dominated by the thermoelastic effect. This is ascribed to the intensification of the thermoelastic effect with the proportional increase in laser irradiation spot area for a given laser power density. Furthermore, both longitudinal and shear wave SCFRs are linearly related to grain size in polycrystalline materials; however, the shear wave SCFR is more sensitive to finer-grained materials. This study holds great significance for evaluating metal material properties using laser ultrasound.
Preparation of entangled W states based on the cavity QED system
Authors: Li 李 Ke 可 , Zhao 赵 Jun-Long 军龙
Published: May 2024

We present a qubit-loss-free (QLF) fusion scheme for generating large-scale atom W states in cavity quantum electrodynamics (QED) system. Compared to the most current fusion schemes which are conditioned on the case where one particle can be extracted from each initial W state to the fusion process, our scheme will access one or two particles from each W state. Based on the atom–cavity-field detuned interaction, three |W〉
n+m+t
states can be generated from the |W〉
n
, |W〉
m
, and |W〉
t
states with the help of two auxiliary atoms, and three |W〉
n+m+t+q
states can be generated from |W〉
n
, |W〉
m
, |W〉
t
, and a |W〉
q
state with the help of three auxiliary atoms. Comparing the numerical simulations of the resource cost of fusing three small-size W states based on the previous schemes, our fusion scheme seems to be more efficient. This QLF fusion scheme can be generalized to the case of fusing k different or identical particle W states. Furthermore, with no qubit loss, it greatly reduces the number of fusion steps and prepares W states with larger particle numbers.
Influence of network structure on spreading dynamics via tie range
Authors: Li 李 Min 敏 , Song 宋 Yurong 玉蓉 , Song 宋 Bo 波 , Li 李 Ruqi 汝琦 , Jiang 蒋 Guo-Ping 国平 , Hui 张 Zhang 晖
Published: May 2024

There are various phenomena of malicious information spreading in the real society, which cause many negative impacts on the society. In order to better control the spreading, it is crucial to reveal the influence of network structure on network spreading. Motifs, as fundamental structures within a network, play a significant role in spreading. Therefore, it is of interest to investigate the influence of the structural characteristics of basic network motifs on spreading dynamics. Considering the edges of the basic network motifs in an undirected network correspond to different tie ranges, two edge removal strategies are proposed, short ties priority removal strategy and long ties priority removal strategy. The tie range represents the second shortest path length between two connected nodes. The study focuses on analyzing how the proposed strategies impact network spreading and network structure, as well as examining the influence of network structure on network spreading. Our findings indicate that the long ties priority removal strategy is most effective in controlling network spreading, especially in terms of spread range and spread velocity. In terms of network structure, the clustering coefficient and the diameter of network also have an effect on the network spreading, and the triangular structure as an important motif structure effectively inhibits the spreading.
Fusion and one-neutron stripping process for 6Li + 94Zr system around the Coulomb Barrier*
Authors: Su 苏 Xuedou 学斗 , Zhang 张 Guangxin 广鑫 , Hu 胡 Shipeng 世鹏 , Wen 温 Peiwei 琣威 , Soler H. O. , Zhang 张 Gaolong 高龙 , Cai 蔡 Boshuai 博帅 , Yuan 袁 Cenxi 岑溪 , Ferreira J. L. , Jiao 焦 Zhenwei 振威 , Wang 王 Mingli 明李 , Wang 汪 Xiaoyu 小雨 , Huang 黄 Zhen 珍 , Zhang 张 Huanqiao 焕乔 , Zhang 张 Chunlei 春雷 , Wu 吴 Xiaoguang 晓光 , Zheng 郑 Yun 云 , Li 李 Congbo 聪博 , Li 李 Tianxiao 天晓 , Lubian J.
Published: May 2024

The complete and incomplete fusion cross section as well as one-neutron stripping process of 6Li + 94Zr system were measured at the energies around the Coulomb barrier by online γ-ray method. In addition to a 30% suppression factor when compared with the measured total fusion process, the complete fusion cross section in 6Li + 94Zr system was observed to be significantly lower than those in the nearby 6Li + 90, 96Zr system. The new experimental result implies that the coupling with breakup channel in the 6Li-induced fusion processes can be affected by the inner structure of the target, which is still not clear in any available model calculation. For the one-neutron stripping process, the direct production cross sections for each level in 95Zr were extracted and compared with the coupled reaction channel calculation, offering a unique opportunity to examine the single-particle nature of the produced excited states. Given the fact that an overall overestimation of the production cross section for 954-keV and 1618-keV levels was observed in the comparison, further investigation is highly demanded in order to understand the full reaction mechanism for the one-neutron stripping process induced by 6Li.
Influence of peripheral axon geometry and local anatomy on magnetostimulation chronaxie
Authors: Ferris Natalie G , Klein Valerie , Guerin Bastien , Wald Lawrence L , Davids Mathias
Published: May 2024

Objective. Rapid switching of magnetic resonance imaging (MRI) gradient fields induces electric fields that can cause peripheral nerve stimulation (PNS) and so accurate characterization of PNS is required to maintain patient safety and comfort while maximizing MRI performance. The minimum magnetic gradient amplitude that causes stimulation, the PNS threshold, depends on intrinsic axon properties and the spatial and temporal properties of the induced electric field. The PNS strength–duration curve is widely used to characterize simulation thresholds for periodic waveforms and is parameterized by the chronaxie and rheobase. Safety limits to avoid unwanted PNS in MRI rely on a single chronaxie value to characterize the response of all nerves. However, experimental magnetostimulation peripheral nerve chronaxie values vary by an order of magnitude. Given the diverse range of chronaxies observed and the importance of this number in MRI safety models, we seek a deeper understanding of the mechanisms contributing to chronaxie variability. Approach. We use a coupled electromagnetic-neurodynamic PNS model to assess geometric sources of chronaxie variability. We study the impact of the position of the stimulating magnetic field coil relative to the body, along with the effect of local anatomical features and nerve trajectories on the driving function and the resulting chronaxie. Main results. We find realistic variation of local axon and tissue geometry can modulate a given axon’s chronaxie by up to two-fold. Our results identify the temporal rate of charge redistribution as the underlying determinant of the chronaxie. Significance. This charge distribution is a function of both intrinsic axon properties and the spatial stimulus along the nerve; thus, examination of the local tissue topology, which shapes the electric fields, as well as the nerve trajectory, are critical for better understanding chronaxie variations and defining more biologically informed MRI safety guidelines.