bluuebunny/crossref_metadata_2025 huggingface dataset:
Overcoming the trade-off between signal-to-noise ratio and resolution in holographic registration of pulsed terahertz Gauss–Bessel beams
Authors: Tsiplakova E. G. , Grachev Y. V. , Petrov N. V.
Published: August 2024

The measurement of the spatial distribution of the nearly monocyclic terahertz (THz) fields by a raster scanning diaphragm is the widely used approach in THz pulse time-domain holography (PTDH) applied in imaging, optical component design, and wavefront sensing tasks. However, it is historically plagued by a compromise between the balance between the signal-to-noise ratio (SNR) and resolution. To address this challenge and keep both parameters at a high level, we proposed to replace the scanning aperture with the scanning module containing a conjugated diaphragm and lens. This solution allowed us for the first time to experimentally investigate the spatio-temporal dynamics of a Gauss–Bessel beam generated in a widespread low-energy THz system based on a femtosecond laser with a pulse energy of around a dozen nanojoules and a repetition rate of tens of megahertz. In particular, this allowed us to observe the temporal spectrum of the THz Gauss–Bessel field at the beam periphery with SNR ≈0.5, which was not possible using a conventional raster scanning system. A careful numerical analysis of the proposed solution reveals a signal enhancement in the spectral domain of approximately 2.5 times compared to the THz PTDH raster scan detection employing only a diaphragm. Moreover, we have shown that the given solution ensures the temporal profiles remain unaffected by the quadratic phase aberration experienced in conventional raster field scanning with only a single aperture.
Accelerating simulations of strained-film growth by deep learning: Finite element method accuracy over long time scales
Authors: Lanzoni Daniele , Rovaris Fabrizio , Martín-Encinar Luis , Fantasia Andrea , Bergamaschini Roberto , Montalenti Francesco
Published: August 2024

A convolutional neural network is trained on a large dataset of suitably randomized film profiles and corresponding elastic energy densities ρɛ, computed by the finite element method. The trained model provides quantitative predictions of ρɛ for arbitrary profiles, surrogating its explicit calculation, and is used for the time integration of partial differential equations describing the evolution of strained films. The close match found between the neural network predictions and the “ground-truth” evolutions obtained by the finite element method calculation of ρɛ, even after tens-of-thousands of integration time-steps, validates the approach. A substantial computational speed up without significant loss of accuracy is demonstrated, allowing for million-steps simulations of islands growth and coarsening. The intriguing possibility of extending the domain size is also discussed.
Contribution of spin pumping to magnon–magnon coupling in YIG/Py heterostructure
Authors: Jin Ying , Gou Pengyang , Liu Fu , Zhao Yibing , Jiang Changjun
Published: August 2024

We investigate the strong correlation between magnon–magnon coupling (M–M coupling) and coherent spin pumping in yttrium iron garnet/permalloy (Y3Fe5O12, YIG/Py) heterostructure through spin-torque ferromagnetic resonance technique. We demonstrate experimentally that the spin pumping of hybrid modes is the strongest near the coupling region at 295 K, indicating that coherent spin pumping is closely associated with magnon hybridization. Meanwhile, the coupling strength gc increases from 0.26 to 0.37 GHz with temperature reduction from 295 to 260 K, which is attributed to the enhancement of spin pumping, especially the hybrid mode characterized by spin pumping out of Py that provides a pronounced contribution. Furthermore, the increased linewidth of the hybrid mode near the coupling region at low temperatures leads to enhanced spin mixing conductivity. This enhancement, in turn, improves spin pumping. Our experiments discuss the underlying mechanisms that influence coupling strength in detail, providing deeper insights into tuning M–M coupling.
Investigation of the aerodynamic characteristics of the entire operation process of the car–counterweight system within the annular flow field of ultra-high-speed elevators
Authors: Zeng Xiangrui , Zhang Ruijun , He Qin , Yang Longlong , Cong Dongsheng , Wang Xilong
Published: August 2024

The ultra-high-speed elevator car–counterweight system will experience substantial aerodynamic effects when operating at high speeds in the annular flow field, particularly at the moment of intersection. These effects will have a considerable impact on the stability of the elevator's operation. This study utilized the unsteady Reynolds-averaged Navier–Stokes approach to investigate the aerodynamic characteristics of the car–counterweight system's entire operation process. The ultra-high-speed elevator three-dimensional transient model is created using dynamic layering mesh technology and then validated through experiments. We investigate the impact of three crucial factors—acceleration, car height, and contact ratio—on the aerodynamic characteristics of the car and the ventilation effect in the hoistway. Specifically, we analyze the instantaneous variations in the aerodynamic force of the car during the intersection process. The results indicate a rapid change in the car's drag and lift at the moment of intersection, with a greater magnitude of change observed in the pressure drag. The acceleration increases gradually, while the drag peak at the intersection time decreases by 1.8%, 3.0%, and 3.6%, respectively. Additionally, the hoistway exhaust volume ratio decreases by 0.9%, 1.5%, and 2.0%. Compared to the drag peak, the lift peak is more responsive to variations in car height. The contact ratio exhibits a sequential increase, but the lift peak demonstrates an uneven upward pattern with increments of 3.07%, 10.35%, and 16.88%. This study greatly enhances the investigation of the aerodynamic characteristics of ultra-high-speed elevators and offers a crucial point of reference for optimizing elevator design in engineering.
Efficient real space formalism for hybrid density functionals
Authors: Jing Xin , Suryanarayana Phanish
Published: August 2024

We present an efficient real space formalism for hybrid exchange-correlation functionals in generalized Kohn–Sham density functional theory (DFT). In particular, we develop an efficient representation for any function of the real space finite-difference Laplacian matrix by leveraging its Kronecker product structure, thereby enabling the time to solution of associated linear systems to be highly competitive with the fast Fourier transform scheme while not imposing any restrictions on the boundary conditions. We implement this formalism for both the unscreened and range-separated variants of hybrid functionals. We verify its accuracy and efficiency through comparisons with established planewave codes for isolated as well as bulk systems. In particular, we demonstrate up to an order-of-magnitude speedup in time to solution for the real space method. We also apply the framework to study the structure of liquid water using ab initio molecular dynamics, where we find good agreement with the literature. Overall, the current formalism provides an avenue for efficient real-space DFT calculations with hybrid density functionals.
Binary interactions between stationary circular and non-circular cylinders in steady unbounded flow
Authors: Jbara L. , Wachs A.
Published: August 2024

We perform two-dimensional particle resolved direct numerical simulations of the steady cross flow past a pair of interacting circular and non-circular cylinders with the cut-cell method, a sub-class of non-body-conforming methods that provides a sharp description of the boundary, is strictly mass and momentum conservative, and can be easily extended to adaptive grids. We use hierarchically refined Cartesian meshes where we place a reference cylinder (i) at the center of the domain and vary the location of a neighboring cylinder (j). We consider a large parameter space defined by the radius of curvature 2/ζi and 2/ζj ranging from 1 to 0, the angles of incidence αi and αj at values of 0° and 45°, the center-to-center gap ratio G ranging from 1.5 to 20, the alignment angle θ measured between the free-stream flow and the line connecting the centers of the cylinders, ranging from 0° to 360°, and finally the Reynolds number Re varied from 1 to 20. Specifically, we investigate the force and flow disturbances introduced by the neighboring cylinder on the reference cylinder, with a focus on the normalized hydrodynamic drag and lift coefficients and the associated prevailing flow regimes. Our study highlights the substantial impact of both the gap ratio G and the alignment angle θ in delineating distinct flow regimes, each exhibiting distinctive flow characteristics and consistent trends in pressure distributions and variations of the normalized drag and lift coefficients. Generally, the flow and force disturbances become more pronounced when significant interactions between the cylinders occur, whether due to proximity, wake interference, or both. We identify a critical threshold for G, beyond which the flow and force disturbances induced by the neighboring cylinder markedly diminish, except in scenarios dominated by significant wake interactions. Our investigation shows that the documented trends in the flow and force variations exhibit remarkable similarity at Re of 10 and 20, but expectedly deviate at Re=1. Finally, we propose an empirical model to predict the hydrodynamic disturbances between two circular cylinders based on the modulation of the drag Cd,i and lift Cl,i coefficients. Leveraging the periodic nature of Cd,i and Cl,i as a function of the relative angular alignment θ of the neighboring cylinder, we use Fourier series expansions demonstrating accurate reconstruction of the data across a wide parameter space. Furthermore, our model exhibits promising predictive capabilities when applied to unexplored parameter ranges, encompassing scenarios involving non-circular cylinders and interpolated regions of Re and G.
Simplified lattice Boltzmann method on multi-resolution mesh
Authors: He Zheng-Wei , Shu Chang , Chen Zhen
Published: August 2024

The simplified lattice Boltzmann method (SLBM), as a recent advancement in the lattice Boltzmann community, alleviates the intrinsic limitations of the standard lattice Boltzmann method by directly evolving macroscopic properties and nicely preserving numerical stability in high-Reynolds-number simulations. To enhance its capability of handling complex hydrodynamic/acoustic problems and to reduce computational efforts, an improved version of SLBM, which is applicable on multi-resolution mesh, is developed in this article. In this method, smooth transition of physical properties across the interface of meshes with different resolutions is ensured by a novel numerical strategy, which effectively couples the interpolation and the extrapolation algorithms. In the meantime, a rescaling algorithm is proposed to fix the inconsistency of time levels induced by the usage of multi-resolution mesh. Comprehensive evaluations of the accuracy, efficiency, and stability of the new method are carried out through benchmark tests of both hydrodynamic and acoustic problems.
A look at the future of perovskite detectors
Authors: Rogalski A.
Published: August 2024

The perovskite materials have been broadly incorporated into optoelectronic devices due to a number of advantages such as high absorption coefficient, high carrier mobility, long carrier diffusion length, shallow defect levels, and high crystal quality. The rapid technological progress of perovskite devices is related to their relatively simple fabrication process, low production cost, and high efficiency.
Ant mimicry in Australian plant bugs: a new genus (Heteroptera: Miridae: Austromirini: Carenotus gen. nov.), eight new species, myrmecomorphic traits, host plants and distribution
Authors: McMah Arlee , Cassis Gerasimos
Published: August 2024

The Australian plant bug tribe Austromirini consists of ant-mimetic taxa which are poorly known, with no information of their phylogenetic relationships and ant-mimetic traits. In this study, we examined nearly 1000 ingroup specimens and developed a comprehensive morphological dataset comprising 37 characters, which was analysed both weighted and unweighted, using ‘Tree analysis using New Technology’ (TNT) software. A single minimal length phylogenetic tree was found, comprising a monophyletic group of ant-mimetic taxa, that included Myrmecoroides rufescens, Myrmecoridea sp., Kirkaldyella spp. and eight species of a new genus, Carenotus gen. nov. The myrmecomorphic traits of Carenotus and allied ant-mimetic taxa are documented and analysed phylogenetically, in conjunction with genitalic characters. Carenotus is defined by the myrmecomorphic colour patterning of the abdominal venter, whereas the ingroup species relationships are supported by genitalic characters alone. Carenotus is described as new with eight included species as follows: C. arltunga sp. nov., C. louthensis sp. nov., C. luritja sp. nov., C. pullabooka sp. nov., C. scaevolaphilus sp. nov., C. schwartzi sp. nov., C. tanami sp. nov. and C. yuendumu sp. nov. Host plant associations are also documented, ranging from host plant specificity and genus-group preferences to host plant generalism. The distribution of Carenotus species is documented with reference to phytogeographic subregions, with all species being semi-arid and arid dwelling. The male and female genitalia of Kirkaldyella pilosa and K. rugosa are described and illustrated, for comparative and phylogenetic purposes. This research expands our knowledge on the plant bug tribe Austromirini and has broader implications for myrmecomorphic research in the suborder Heteroptera. ZooBank: urn:lsid:zoobank.org:pub:2FF9BE23-38A6-42B4-8488-74F216D8237F
Visibility-informed mapping of potential firefighter lookout locations using maximum entropy modelling
Authors: Mistick Katherine A. , Campbell Michael J. , Dennison Philip E.
Published: August 2024

Background Situational awareness is an essential component of wildland firefighter safety. In the US, crew lookouts provide situational awareness by proxy from ground-level locations with visibility of both fire and crew members. Aims To use machine learning to predict potential lookout locations based on incident data, mapped visibility, topography, vegetation, and roads. Methods Lidar-derived topographic and fuel structural variables were used to generate maps of visibility across 30 study areas that possessed lookout location data. Visibility at multiple viewing distances, distance to roads, topographic position index, canopy height, and canopy cover served as predictors in presence-only maximum entropy modelling to predict lookout suitability based on 66 known lookout locations from recent fires. Key results and conclusions The model yielded a receiver-operating characteristic area under the curve of 0.929 with 67% of lookouts correctly identified by the model using a 0.5 probability threshold. Spatially explicit model prediction resulted in a map of the probability a location would be suitable for a lookout; when combined with a map of dominant view direction these tools could provide meaningful support to fire crews. Implications This approach could be applied to produce maps summarising potential lookout suitability and dominant view direction across wildland environments for use in pre-fire planning.
Fabrication of ultra-low expansion glass based double paddle oscillator
Authors: Jose Sabitha Ann , Atwa Yahya , Iqbal Faisal , McNeill David , Shakeel Hamza
Published: August 2024

Ultra-low expansion (ULE) glasses, with their excellent material properties like low thermal expansion coefficient (0.5 ppm K−1), are highly suitable for manufacturing micromechanical resonators. However, the lack of suitable microfabrication processes primarily limits the use of ULE glasses to macroscopic applications. This paper describes a detailed micro fabrication technique for producing double paddle oscillators (DPOs) using ULE glass substrates. We used a combination of low-pressure chemical vapor deposition (LPCVD), lithography, and wet etching techniques to manufacture millimeter sized mechanical oscillator with a thickness of 500 μm. We utilized a thick layer of LPCVD polysilicon (∼2.5 μm) as a hard mask for double side etching of thick ULE substrate. We were able to successfully identify different resonant modes of the DPOs using both electrostatic and optical detection methods. A laser Doppler vibrometer system was utilized to confirm different simulated resonant modes. Additionally, quality factor was extracted for different modes from ring down measurements for the first time in ULE based DPO.
Dispersion compensation design of high-density stacking RFSS absorbers for wideband applications
Authors: Luo Zhinan , Ding Xiaoxiao , Yang Jie , Wu Yuhan , Wang Bichao , Miao Ling , Bie Shaowei , Jiang Jianjun
Published: August 2024

A dispersion compensation design absorber realized by high-density stacking resistive frequency selective surface (RFSS) is proposed for wideband applications. Firstly, the quantitative relationship between the equivalent impedance of RFSS and the permittivity of the effective media is constructed with the help of the transmission matrix method. The dispersion regulation of permittivity is achieved by changing the pattern and the square resistance of RFSS. In terms of absorber design, a uniform absorber with dispersion manipulation is developed as a precursor absorber. The uniform absorber has an absorption performance better than −8.5 dB above 2 GHz at normal incidence. The loss mechanism is analyzed in detail by electric field distribution and surface power loss density distribution, indicating that the uniform design cannot achieve thickness saving when extending to low frequency. Therefore, a dispersion compensation design absorber is proposed to extend −10 dB bandwidth to 1.64–28.8 GHz. Experiment results agree well with the simulation results, validating the analytic methods and design principles.
Tailoring thermal transport and confinement effect of GaN/Si3N4 nanowires utilizing core–shell architecture
Authors: Yang Yuting , Yuan Kunpeng , Wang Zhaoliang
Published: August 2024

The thermal transport properties of nanowires (NWs) can be significantly influenced by the implementation of a core–shell structure, which introduces interface scattering and phonon localization effects, opening avenues for novel applications. In this paper, we use the method of non-equilibrium molecular dynamics to simulate the effects of system temperature, cross-sectional width, and nanopillar interface on the thermal transport of GaN/Si3N4 core–shell NWs. The thermal transport process of phonons in core–shell NWs is studied by calculating the vibrational density of states, phonon participation rate, and dispersion curve. The results show that the core–shell NWs characterized by smooth interfaces exhibit a 17.4% decrease in thermal conductivity (TC) at room temperature when contrasted with pristine GaN NWs. Furthermore, the TC of GaN/Si3N4 core–shell NWs can be further reduced by adding nanopillars at the interface. Due to resonance effect, thus effectively regulating the thermal transport. The presence of nanopillars increases phonon–surface scattering intensity at low-frequency and modifies phonon dispersion to decrease the group velocity. In addition, the hybridization of phonon modes between those of the nanopillars and the Si3N4 shell gives rise to numerous dispersionless resonance phonon modes that span the entire phonon spectrum. This research delves into the effects of nanopillars and interfaces on thermal transport, providing important guidance for understanding confinement effects and establishing a robust theoretical basis for the regulation of thermal transport.
Exploring the potential of 3D printing for shape memory alloys: a critical review
Authors: Ahmad Shadab , Hashmi Abdul Wahab , Iqbal Faiz , Rab Shanay , Tian Yebing
Published: August 2024

Shape memory alloys (SMAs) have garnered substantial attention due to their remarkable properties and diverse applications with 3D printing techniques. The present work comprehensively reviews 3D printing applied to various SMAs. The paper examines different 3D printing techniques for SMAs and discusses the process parameters crucial for printability. The potential of 3D printing SMAs lies in the ability to create complex geometries and customized designs that are unattainable through conventional manufacturing methods. Thus, 3D printed SMAs are used across diverse fields, including biomedicine, aerospace, engineering, and consumer goods. While recognizing the notable progress achieved, the review addresses ongoing challenges such as attaining consistent microstructures, post-processing and cost-effective production. It also highlights future prospects, including the development of new SMAs compositions, and expanded applications in various other fields. As a result, the review offers a succinct and comprehensive report on SMAs using 3D printing, which could serve as a useful resource for scientists, engineers, researchers, and industry in their future work.
Effects of size and shape of hole defects on mechanical properties of biphenylene: a molecular dynamics study
Authors: Xiao Shuoyang , Hao Jiannan , Shi Tan , Jin Jianfeng , Wu Bin , Peng Qing
Published: August 2024

The distinctive multi-ring structure and remarkable electrical characteristics of biphenylene render it a material of considerable interest, notably for its prospective utilization as an anode material in lithium-ion batteries. However, understanding the mechanical traits of biphenylene is essential for its application, particularly due to the volumetric fluctuations resulting from lithium ion insertion and extraction during charging and discharging cycles. In this regard, this study investigates the performance of pristine biphenylene and materials embedded with various types of hole defects under uniaxial tension utilizing molecular dynamics simulations. Specifically, from the stress‒strain curves, we obtained key mechanical properties, including toughness, strength, Young’s modulus and fracture strain. It was observed that various near-circular hole (including circular, square, hexagonal, and octagonal) defects result in remarkably similar properties. A more quantitative scaling analysis revealed that, in comparison with the exact shape of the defect, the area of the defect is more critical for determining the mechanical properties of biphenylene. Our finding might be beneficial to the defect engineering of two-dimensional materials.
A linear compensation method for inference accuracy improvement of memristive in-memory computing
Authors: Dai Yuehua , Wang Zeqing , Feng Zhe , Zou Jianxun , Guo Wenbin , Tan Su , Yu Ruihan , Hu Yang , Qian Zhibin , Hu Junliang , Xu Zuyu , Zhu Yunlai , Wu Zuheng
Published: August 2024

Memristive computing system (MCS), with the feature of in-memory computing capability, for artificial neural networks (ANNs) deployment showing low power and massive parallelism, is a promising alternative for traditional Von-Neumann architecture computing system. However, because of the various non-idealities of both peripheral circuits and memristor array, the performance of the practical MCS tends to be significantly reduced. In this work, a linear compensation method (LCM) is proposed for the performance improvement of MCS under the effect of non-idealities. By considering the effects of various non-ideal states in the MCS as a whole, the output error of the MCS under different conditions is investigated. Then, a mathematic model for the output error is established based on the experimental data. Furthermore, the MCS is researched at the physical circuit level as well, in order to analyze the specific way in which the non-idealities affect the output current. Finally, based on the established mathematical model, the LCM output current is compensated in real time to improve the system performance. The effectiveness of LCM is verified and showing outstanding performance in the residual neural network-34 network architecture, which is easily affected by the non-idealities in hardware. The proposed LCM can be naturally integrated into the operation processes of MCS, paving the way for optimizing the deployment on generic ANN hardware based on the memristor.
The adsorption performance of harmful gas (CO, SO) on doped graphene: a first-principle study
Authors: Liu Yufeng , Shen Yang , Liu Guanpeng , Tu Wenbing , Ni Jiaming
Published: August 2024

The adsorption of gas molecules (CO, SO) by different atoms (Cu, Fe, Pd, Pt, B, N, P, S) doped graphene has been investigated in terms of adsorption energies, charge transfer, and density of states based on the density functional theory. The Result that the metal atoms enhance the interaction of graphene with the above gas molecules much more than the non-metal atoms, and it is due to this strong interaction that the gas molecules (CO, SO) chemisorb on graphene doped with metal atoms. Meanwhile, the metal atom doped graphene is more sensitive to SO molecules. Moreover, the charge transfer of CO/Pd–G is 0.056e, and the adsorption energy is −6.386 eV, and there is a very large deformation of Pt–G after adsorption of SO and the reaction is very violent, with an adsorption energy up to −7.922 eV and a charge transfer up to 0.537e, which is the highest of all systems. Therefore, we believe that Pt–G is suitable for the detection of the SO while Pd–G is suitable for the detection of the CO. In addition, combined with the nature of the work function, we believe that metal-doped graphene has the potential to be a highly sensitive irreversible sensor.
Structural health monitoring for 3D-printed civil infrastructures: a review of challenges, applications and future directions
Authors: Parida Lukesh , Moharana Sumedha
Published: August 2024

The integration of 3D printed constructions into civil projects has created new opportunities for economically efficient construction. However, preserving the long-term structural integrity of 3D-printed structures poses considerable challenges. This study covers the importance of structural health monitoring (SHM) and deployment of sensors for condition monitoring of 3D-printed civil infrastructure. It explores a wide range of sensors that might be used for continual evaluation and assessment of structural efficiency and the challenges related to SHM in these components. The report provides cost benefit analysis and case studies describing effective sensor installations in 3D-printed structures, demonstrating the ability of the technology to enhance the safety and integrity of infrastructure systems. It also identifies potential challenges and issues that must be resolved before sensor-based SHM can be successfully used in 3D-printed civil structures. The research emphasizes the potential of maintenance planning and decision support systems for optimizing maintenance schedules, reducing downtime, and increasing cost-effectiveness. This research is critical for academics, engineers, and professionals using sensors for 3D-printed structural systems.
Active acoustic metamaterials with on-demand bulk modulus and full mass density tensor
Authors: Kovacevich Dylan A , Popa Bogdan-Ioan
Published: August 2024

Active metamaterials address fundamental limitations of passive media and have widely been recognized as necessary in numerous compelling applications such as cloaking and extreme noise absorption. However, most practical devices of interest have yet to be realized due to the lack of a suitable strategy for implementing bulk active metamaterials—those that involve interacting cells and functionality beyond one dimension. Here, we present such an active acoustic metamaterial design with bulk modulus and anisotropic mass density that can be independently programmed over wide value ranges. We demonstrate this ability experimentally in several examples, targeting acoustic properties that are hard to access otherwise, such as a bulk modulus significantly smaller than air, strong mass density anisotropy, and complex bulk modulus and mass density for high reflectionless sound absorption. This work enables the transition of active acoustic metamaterials from isolated proof-of-concept demonstrations to versatile bulk materials.
Bipolar topological spin diode and topological spin transistor in finite size quantum spin Hall insulators
Authors: Luo Kun , Chen Xi-Rong
Published: August 2024

The miniaturization and stability of electronic devices are becoming increasingly important today. We attempt to provide the theoretical support for designing spintronic devices by numerically investigating spin transport in finite size quantum spin Hall insulators (QSHI) under a perpendicular weak magnetic field. By modifying magnetic field strength, we find the gapped spin up and spin down bands are split to realize a half-metal phase which is a promising candidate for designing an efficient spin filter. Moreover, one of the two energy gaps becomes larger and the other smaller due to the weakened or enhanced coupling between two edge states. Here we propose and demonstrate the spin filter based on a finite size QSHI junction under a magnetic field and the polarity can be inverted by a bias voltage or magnetic field. Interestingly, we find a bipolar spin diode effect that only one spin channel is opened and the other spin channel is closed at positive bias, and the opposite spin electron can be transmitted with negative bias. Two spin filters in series can be a spin transistor, the on and off states can be controlled by spin polarization of one spin filter. We show that the topological spin transistor can be controlled by the gate voltage, and it survives in moderate disorder.
SOS decomposition for general Bell inequalities in two qubits systems and its application to quantum randomness
Authors: Zhao Wen-Na , Xiao Youwang , Li Ming , Xu Li , Fei Shao-Ming
Published: August 2024

Bell non-locality is closely related with device independent quantum randomness. In this paper, we present a kind of sum-of-squares (SOS) decomposition for general Bell inequalities in two qubits systems. By using the obtained SOS decomposition, we can then find the measurement operators associated with the maximal violation of considered Bell inequality. We also practice the SOS decomposition method by considering the (generalized) Clauser-Horne-Shimony-Holt (CHSH) Bell inequality, the Elegant Bell inequality, the Gisin inequality and the Chained Bell inequality as examples. The corresponding SOS decompositions and the measurement operators that cause the maximum violation values of these Bell inequalities are derived, which are consistent with previous results. We further discuss the device independent quantum randomness by using the SOS decompositions of Bell inequalities. We take the generalized CHSH inequality with the maximally entangled state and the Werner state that attaining the maximal violations as examples. Exact value or lower bound on the maximal guessing probability using the SOS decomposition are obtained. For Werner state, the lower bound can supply a much precise estimation of quantum randomness when p tends to 1.
Symmetric structures and dynamic analysis of a (2+1)-dimensional generalized Benny-Luke equation
Authors: Sun Jie , Zhao Qiulan , Li Xinyue
Published: August 2024

We study the symmetric structures and dynamic analysis of a (2 + 1)-dimensional generalized Benny-Luke (GBL) equation based on the Lie symmetry method, the GBL equation is an important non-integrable model of water waves. Specifically, we construct multiple exact solutions of the GBL equation and obtain its nonlocally related systems. Firstly, the Lie point symmetries and conservation laws of the GBL equation are computed, and then we get the reduced ordinary differential equation from one of the conservation laws. Multiple methods, for example, the dynamical systems method, the power series method, the homogeneous balancing method and generalized variable separation method, are used to solve the ordinary differential equation and abundant exact solutions of the GBL equation are got. Finally, we extend these exact solutions by discrete symmetries, and give three-dimensional graphs of partial exact solutions. In addition, we construct the nonlocally related PDE systems, which contains the potential systems from the conservation laws and an inverse system from a Lie point symmetry of the GBL equation. These findings reveal the dynamical behavior behind the GBL equation and broaden the range of nonlinear water wave model solutions.
Non-Hermitian quantum walks and non-Markovianity: the coin-position interaction
Authors: Badhani Himanshu , Banerjee Subhashish , Chandrashekar C M
Published: August 2024

A

P
T

-symmetric, non-Hermitian Hamiltonian in the

P
T

-unbroken regime can lead to unitary dynamics under the appropriate choice of the Hilbert space. The Hilbert space is determined by a Hamiltonian-compatible inner product map on the underlying vector space, facilitated by a ‘metric operator’. A more traditional method, however, involves treating the evolution as open system dynamics, and the state is constructed through normalization at each time step. In this work, we present a comparative study of the two methods of constructing the reduced dynamics of a system evolving under a

P
T

-symmetric Hamiltonian. Our system is a one-dimensional quantum walk with the spin and position degrees of freedom forming its two subsystems. We compare the information flow between the subsystems under the two methods. We find that under the metric formalism, a power law decay of the information backflow to the subsystem gives a clear indication of the transition from

P
T

-unbroken to the broken phase. This is unlike the information backflow under the normalized state method. We also note that even though non-Hermiticity models open system dynamics, pseudo-Hermiticity can increase entanglement between the subsystem in the metric Hilbert space, thus indicating that pseudo-Hermiticity cases can be seen as a resource in quantum mechanics.
Nonlinear friction dynamics of water-lubricated bearings under transient shocks considering cavitation and turbulence effects
Authors: Chen Ziqi , Wang Ji , Li Rui , Liu Yujun
Published: August 2024

This study proposes a transient elastohydrodynamic mixed lubrication (EHML) model for water-lubricated bearings (WLBs) that incorporates cavitation and turbulence effects to evaluate the nonlinear friction dynamic performance under transient shock loads. The generalized average Reynolds equation is discretized using the control volume technique (CVM), and the constrained system is solved using the Fischer-Burmeister-Newton-Schur (FBNS) method. The validity of the model is verified by a comparison of experimental data from published literature. On this basis, the effects of cavitation, turbulence, shock load amplitude, direction, time, and rotational speed on WLB nonlinear friction dynamics characteristics are investigated. The results show that cavitation induces hydrodynamic loss under transient shock conditions, significantly increases contact time and load, and exacerbates the hydrodynamic instability phenomenon. In contrast, the turbulence effect effectively reduces frictional contact. The stability of WLBs under transient shock conditions is closely related to the load offset angle. Reducing the load offset angle improves the anti-shock stability of the bearings. Nevertheless, an increase in the amplitude and duration of the shock load may result in a deterioration of the frictional contact behavior. Increasing the rotational speed appropriately favors accelerating the lubrication regime transition and improving WLB’s anti-shock stability. This study provides a reference for enhancing WLB anti-shock performance and optimizing structural design.
On the capability of high redshift kSZ measurement with galaxy surveys
Authors: Chen Ziyang , Zhang Pengjie
Published: August 2024

The kinematic Sunyaev-Zel'dovich (kSZ) effect has been detected at z < 1 using various
techniques and data sets. The ongoing and upcoming spectroscopic galaxy surveys such as DESI (Dark
Energy Spectroscopic Instrument) and PFS (Prime Focus Spectrograph) will push the detection beyond
z = 1, and therefore map the baryon distribution at high redshifts. Such detection can be
achieved by both the kSZ stacking and tomography methods. While the two methods are theoretically
equivalent, they differ significantly in the probed physics and scales, and required data
sets. Taking the combination of PFS and ACT (Atacama Cosmology Telescope) as an example, we build
mocks of kSZ and galaxies, quantify the kSZ detection S/N, and compare between the two methods.
We segment the PFS galaxies into three redshift bins: 0.6 < z < 1.0, 1.0 < z < 1.6, and 1.6 <
z < 2.4. For tomography method, our analysis reveals that the two higher redshift bins exhibit
significantly higher S/N ratios, with values of 32 and 28, respectively, compared to the first
redshift bin, which yielded an S/N of 8. This is attributed to not only the increasing of electron
density with redshifts, but also the larger survey volume and the reduced non-linearity,
facilitating velocity reconstruction at higher redshifts. Therefore, the capability of the PFS
survey to measure high redshift kSZ effect stands as a substantial advantage over other
spectroscopic surveys at lower redshift. The S/N of kSZ stacking largely depends on the number of
galaxy groups available from another photometric survey. But in general, its S/N is lower than
that of kSZ tomography, largely due to CMB instrument noise and error in galaxy group redshift.
Incorporating next-generation CMB surveys like CMB-S4, characterized by significantly reduced
instrument noise and improved angular resolution, is expected to enhance tomographic detection by
a factor of ten and stacking detection by fivefold. This future high S/N detection holds the
promise of not only providing precise constraints on the overall baryon abundance but also
initiating a new insight into baryon distribution.
Analytical proxy to families of numerical solutions: the case study of spherical mini-boson stars
Authors: Yang Jianzhi , Cunha Pedro V.P. , Herdeiro Carlos A.R.
Published: August 2024

The Einstein field equations, or generalizations thereof, are difficult to solve analytically. On the other hand, numerical solutions of the same equations have become increasingly common, in particular concerning compact objects. Whereas analytic approximations to each individual solution within a numerical family have been proposed, proxies for whole families are missing, which can facilitate studying properties across the parameter space, data compression and a wider usage of such solutions. In this work we tackle this need, proposing a simple strategy based on two different
expansions of the unknown functions in an appropriately chosen basis, to build such proxy. We use as an exploratory case-study spherical, fundamental mini-boson stars, to illustrate the feasibility of such an approach, emphasise its advantage in reducing the data size, and the challenges, say, in covering large parameter spaces.
Protecting coherence by weak measurement and quantum measurement reversal
Authors: Wang Qiong , He Zhi
Published: August 2024

The dynamic behavior of the relative entropy of coherence for a two-level system is systematically investigated in different regimes. We derive the exact expressions of relative entropy quantifying coherence for an exactly solving model consisting of single qubit interacting with independent structured reservoir, show explicitly that the weak measurement (WM) and quantum measurement reversal (QMR) operation indeed help for protecting the coherence. In addition, the freezing phenomenon of the coherence can be detected by using the optimal WM and QMR operation.
The study on 4D culture system of squamous cell carcinoma of tongue
Authors: Xing Yuhang , Wang Yuezhu , Wang Ruiqi , Sun Xiangyu , Min Zhang , Tian Weiming , Jing Guangping
Published: August 2024

Traditional cell culture methods often fail to accurately replicate the intricate microenvironments crucial for studying specific cell growth patterns. In our study, we developed a 4D cell culture model—a precision instrument comprising an electromagnet, a force transducer, and a cantilever bracket. The experimental setup involves placing a Petri dish above the electromagnet, where gel beads encapsulating magnetic nanoparticles and tongue cancer cells are positioned. In this model, a magnetic force is generated on the magnetic nanoparticles in the culture medium to drive the gel to move and deform when the magnet is energized, thereby exerting an external force on the cells. This setup can mimic the microenvironment of tongue squamous cell carcinoma CAL-27 cells under mechanical stress induced by tongue movements. Electron microscopy and rheological analysis were performed on the hydrogels to confirm the porosity of alginate and its favorable viscoelastic properties. Additionally, Calcein-AM/PI staining was conducted to verify the biosafety of the hydrogel culture system. It mimics the microenvironment where tongue squamous cell carcinoma CAL-27 cells are stimulated by mechanical stress during tongue movement. Electron microscopy and rheological analysis experiments were conducted on hydrogels to assess the porosity of alginate and its viscoelastic properties. Calcein-AM/PI staining was performed to evaluate the biosafety of the hydrogel culture system. We confirmed that the proliferation of CAL-27 tongue squamous cells significantly increased with increased matrix stiffness after 5 d as assessed by MTT. After 15 d of incubation, the tumor spheroid diameter of the 1%-4D group was larger than that of the hydrogel-only culture. The Transwell assay demonstrated that mechanical stress stimulation and increased matrix stiffness could enhance cell aggressiveness. Flow cytometry experiments revealed a decrease in the number of cells in the resting or growth phase (G0/G1 phase), coupled with an increase in the proportion of cells in the preparation-for-division phase (G2/M phase). RT-PCR confirmed decreased expression levels of P53 and integrin β3 RNA in the 1%-4D group after 21 d of 4D culture, alongside significant increases in the expression levels of Kindlin-2 and integrin αv. Immunofluorescence assays confirmed that 4D culture enhances tissue oxygenation and diminishes nuclear aggregation of HIF-1α. This device mimics the microenvironment of tongue cancer cells under mechanical force and increased matrix hardness during tongue movement, faithfully reproducing cell growth in vivo, and offering a solid foundation for further research on the pathogenic matrix of tongue cancer and drug treatments.
Functional poly(e-caprolactone)/SerMA hybrid dressings with dimethyloxalylglycine-releasing property improve cutaneous wound healing
Authors: Wang Yajie , Li Xinyi , Wu Xinyue , Meng Fei , Li Ziming , Guo Wengeng , Gao Zhixian , Zhu Changjun , Peng Yuan
Published: August 2024

Medical dressings with multifunctional properties, including potent regeneration capability and good biocompatibility, are increasingly needed in clinical practice. In this study, we reported a novel hybrid wound dressing (PCL/SerMA/DMOG) that combines electrospun PCL membranes with DMOG-loaded methacrylated sericin (SerMA) hydrogel. In such a design, DMOG molecules are released from the hybrid dressing in a sustained manner in vitro. A series of in vitro assays demonstrated that DMOG-loaded hybrid dressing has multiple biological functions, including promotion of human umbilical vein endothelial cells proliferation and migration, in vitro vascularization, and the generation of intracellular NO. When applied to the cutaneous wound, the PCL/SerMA/DMOG dressing significantly accelerated wound closure and tissue regeneration by promoting angiogenesis in the wound area, collagen deposition, and cell proliferation within the wound bed. These results highlight the potential clinical application of PCL/SerMA/DMOG hybrid dressings as promising alternatives for accelerating wound healing via improved biocompatibility and angiogenesis amelioration.
Production and Investigation of the 150 CC Engine Performance with Bioethanol from Manihot Esculenta Cassava and RON 92 Fuel Mixture
Authors: Setiyawan A , Faksi S , Fitriyana D F , Aryadi W , Naryanto R F , Darsono F B , Bahatmaka A , Kriswanto  , Rusiyanto  , Gumelar Syafei M. H. , Pratiwi I
Published: August 2024

This study aimed to determine bioethanol’s characteristics in the form of ethanol content, density, and pH, as well as the effect of a mixture of perlite and bioethanol fuel on torque, power, and the best composition. The approach used is quantitative, in the form of a true experimental design, namely the posttest-only control design, and uses descriptive data analysis methods from the results of testing for ethanol content, density, pH, torque, and power. The results of the ethanol characteristic test were 89.31% ethanol content, 0.7705 g/mL density, and pH 7.624. The average torque increases by 2.24% with an average power of 2.52% at 20% mix. The engine speed of 7.500 and 8.750 rpm increased maximum torque and power by 2.81% with a value of 14.32 Nm and 3.13% with a value of 11.83 kW at 20% mixture. Suggestions, improve the fermentation and distillation processes to increase the amount of bioethanol produced using the same raw materials and optimize the blending of bioethanol fuel in the engine, considering factors such as fuel availability, efficiency, and environmental impact.
Integrated optics: conventional Mach–Zehnder interferometer configuration versus loop terminated Mach–Zehnder interferometer configuration–a perspective
Authors: Butt Muhammad Ali
Published: August 2024

This paper presents a comparative analysis of the conventional Mach–Zehnder interferometer (MZI) configuration and the loop-terminated MZI (LT-MZI) configuration, emphasizing their respective advantages and utilization in sensing applications. The conventional MZI, renowned for its simplicity and versatility, is contrasted with the LT-MZI, which incorporates a loop termination to enhance sensitivity and spectral performance. Through a detailed examination of design principles, operational mechanisms, and performance metrics, it is shown that the LT-MZI configuration offers superior sensitivity and improved interference pattern control, making it particularly suitable for high-precision sensing applications. This perspective provides valuable insights into the selection and optimization of MZI configurations for specific photonic sensing needs.
Optimization of polarization spectroscopy signal for laser-frequency stabilization
Authors: Bala Rajni , Ghosh Joyee , Venkataraman Vivek
Published: August 2024

We experimentally generate polarization spectroscopy (error) signals corresponding to the D2-line hyperfine transitions,

F
g

=
2
→

F
e

=
1
,
2
,
3

of 87Rb, and

F
g

=
3
→

F
e

=
2
,
3
,
4

of 85Rb, and show that the strongest error signals correspond to the closed hyperfine transitions (oscillator strength

∼

0.7

),

F
g

=
2
→

F
e

=
3

and

F
g

=
3
→

F
e

=
4

, respectively. We make the generated error signal robust to fluctuations in external parameters by finding optimum values for the vapor cell temperature and pump-probe intensities at two different beam diameters. We further employ these optimized error signals to directly (without the need for frequency/phase modulation) lock the laser frequency—reducing the rms drift/linewidth from

∼

10

MHz to

<

500

kHz, when measured over a

∼

60

min duration. In addition, by comparing theoretically calculated and experimentally measured error signals for the pump intensities ranging from

∼

0.1

I

sat
0

−
10

I

sat
0

(where,

I

sat
0

∼
1.6

mW cm−2 is the two-level saturation intensity for the Rb D2-line transitions), we discuss the applicability and limitations of existing numerical and analytical approaches based on a full multi-level rate equation model for polarization spectroscopy.