Order Modes Research Articles

Hybrid Hermite–Laguerre–Gaussian vector modes

Vector modes are well-defined field distributions with spatially varying polarization states, rendering them irreducible to the product of a single spatial mode and a single polarization state. Traditionally, the spatial degree of freedom of vector modes is constructed using two orthogonal modes from the same family. Here, we introduce a novel class of vector modes whose spatial degree of freedom is encoded by combining modes from both the Hermite– and Laguerre–Gaussian families, ensuring that the modes are shape-invariant upon propagation. This superposition is not arbitrary, and we provide a detailed explanation of the methodology employed to achieve it. This new class of vector modes, which we term hybrid Hermite–Laguerre–Gaussian (HHLG) vector modes, gives rise to subsets of modes exhibiting polarization dependence on propagation due to the difference in mode orders between the constituent modes, while remaining eigenmodes of free space. To the best of our knowledge, this is the first demonstration of vector modes composed of two scalar modes originating from different families.

Intra-Mode Backward Stimulated Brillouin Scattering in Lithium Niobate Micron Fibers

The Brillouin sensing technology in multimode optical fibers has garnered significant attention due to its capability for simultaneous modal transmission of multiple parameters, such as temperature and strain, which confer it higher information capacity and transmission efficiency. Additionally, lithium niobate, with their excellent electro-optical properties, show potential application value in the sensing field and are expected to provide higher sensitivity and precision. However, owing to the maturity of manufacturing processes, current research on fiber optic sensing predominantly focuses on silicon-based materials, with relatively fewer studies dedicated to fibers using lithium niobate as the core material, thus underestimating its application potential. This paper investigates the theoretical aspects of Brillouin scattering effects in lithium niobate optical fibers. We simulate the intra-mode backward Brillouin scattering characteristics of the first five orders of LP modes in micrometer-scale lithium niobate fibers by means of finite-element simulation, in order to explore its intrinsic law.<br>First of all, the relationship between the Brillouin frequency shift and gain for the first five optical mode interactions is analyzed in detail. The results showed that in the case of intra mode BSBS, the peak of BFS would exhibit a significant redshift, ranging from 20.63 GHz to 18.747 GHz. The Brillouin gain coefficient would also decrease from 13.503 m<sup>−1</sup>·W<sup>−1</sup> to 4.0115 m<sup>−1</sup>·W<sup>−1</sup> with increasing mode order, in which mode LP<sub>01</sub> having the strongest gain intra modal interaction means the best sensing sensitivity. In addition, compared with ordinary silica fiber, the Brillouin gain of lithium niobate fiber is increased by about 5 orders of magnitude, which means that fibers with lithium niobate as the core can have higher sensing sensitivity. In addition, we found that although there are significant differences in the Brillouin frequency shift values of each order of optical modes under intra modal interactions, the sound velocity of their corresponding acoustic modes is always consistent under the same acoustic mode. In data processing, we noticed that this is because as the mode order changes, the corresponding effective refractive index also decreases to ensure that each acoustic mode of the material always has the same sound velocity. These findings provide the basis for lithium niobate fiber sensors with electro-optic properties.

PERK transition–induced directional mode switching promotes epithelial tumor cell migration

Increasing evidence suggests that tumor cells exhibit extreme plasticity in migration modes in order to adapt to microenvironments. However, the underlying mechanism for governing the migration mode switching is still unclear. Here, we revealed that epithelial tumor cells could develop a stable directional mode driven by hyperactivated ERK activity. This highly activated and dynamically changing ERK activity, called pERK transition, is crucial for inducing the switch from pauses state to directional movement and is also necessary for maintaining epithelial tumor cells in the directional mode. PERK transition integrated pERK surf, the dynamic and localized ERK activity at the leading edge. The sequential activation of RhoA and Rac1 by pERK transition played critical roles in generation of pERK surf activity through a movement feedback mechanism. PERK transition activity converted the orderly collective migration into the disordered dispersal movement, enhanced the invasiveness of epithelial tumor cells, and promoted their metastasis in immune-deficient mice. These findings revealed that the exquisite spatiotemporal organization of ERK activity orchestrates migration and invasion of tumor cells and provide evidence for the mechanism underlying migration mode switching in epithelial tumor cells.

Influence of Lamb Wave Anisotropy on Detection of Water-to-Ice Phase Transition.

An important technical task is to develop methods for recording the phase transitions of water to ice. At present, many sensors based on various types of acoustic waves are suggested for solving this challenge. This paper focuses on the theoretical and experimental study of the effect of water-to-ice phase transition on the properties of Lamb and quasi shear horizontal (QSH) acoustic waves of a higher order propagating in different directions in piezoelectric plates with strong anisotropy. Y-cut LiNbO3, 128Y-cut LiNbO3, and 36Y-cut LiTaO3 plates with a thickness of 500 μm and 350 μm were used as piezoelectric substrates. It was shown that the amplitude of the waves under study can decrease, increase, or remain relatively stable due to the water-to-ice phase transition, depending on the propagation direction and mode order. The greatest decrease in amplitude (42.1 dB) due to glaciation occurred for Lamb waves with a frequency of 40.53 MHz and propagating in the YX+30° LiNbO3 plate. The smallest change in the amplitude (0.9 dB) due to glaciation was observed for QSH waves at 56.5 MHz propagating in the YX+60° LiNbO3 plate. Additionally, it was also found that, in the YX+30° LiNbO3 plate, the water-to-ice transition results in the complete absorption of all acoustic waves within the specified frequency range (10-60 MHz), with the exception of one. The phase velocities, electromechanical coupling coefficients, elastic polarizations, and attenuation of the waves under study were calculated. The structures "air-piezoelectric plate-air", "air-piezoelectric plate-liquid", and "air-piezoelectric plate-ice" were considered. The results obtained can be used to develop methods for detecting ice formation and measuring its parameters.

Wideband Tuning and Deep-Tissue Spectral Detection of Indium Phosphide Nano-Laser Particles.

Laser particles (LPs) emitting narrowband spectra across wide spectral ranges are highly promising for high-multiplex optical barcoding. Here, we present LPs based on indium phosphide (InP) nanodisks, operating in the near-infrared wavelength range of 740-970 nm. Utilizing low-order whispering gallery resonance modes in size-tuned nanodisks, we achieved an ultrawide color palette with 27% bandwidth utilization and nanometer-scale linewidth. The minimum laser size was 430 nm in air and 560 nm within the cytoplasm, operating at mode order 4 or 5. We further demonstrated spectral detection of laser peaks with high signal-to-background ratios in highly-scattering media, including 1-cm-thick chicken breast tissue and blood vessels in live mice.

Behavior of TE and TM propagation modes in nanomaterial graphene using asymmetric slab waveguide

Abstract In this article, the conduction of transverse electric/transverse magnetic (TE/TM) propagation modes in nanomaterial graphene utilization of asymmetric dielectric slab waveguide was studied in terms of their applicability in optical fiber communication. Nano-graphene film was deposited on silica substrate and air cladding. Three layers were exposed to electromagnetic waves with a 1.55 µm wavelength and 1 µm thick nanographene film, silica, and air covering to study the performance and optical properties of graphene nanomaterials. The models were influenced by factors such as attenuation wavenumbers, cut-off frequency, mode number, propagation wavenumbers, skin depth, and angles of total internal reflection. The impact of these parameters was assessed through numerical analysis, revealing significant correlations. The modes generated ten numbers of TE and nine numbers of TM mode dependent upon the structure of nanographene, with low loss propagation wavenumber. As the TE/TM modes increase, the decay wavenumbers of the cladding and substrate parameters diminish. This indicates that the magnetic and electric fields undergo extremely rapid decay beyond the film region, which leads to the skin depth for higher TE/TM modes traveling longer distances in the cladding and substrate than do lower-order modes. Therefore, nanographene exhibits good optical properties due to its low absorption loss. The angles of internal reflection are greater in magnitude than the substrate and cladding key angles. Still, in the tenth TE mode, the internal reflection angles are extremely close to the critical angle as a result of the small substrate decay parameter and the near operating frequency. The tenth TE mode is weakly characterized. The characteristics of TE/TM modes in an asymmetric three-layer slab waveguide structure are realized for various mode orders and various parameters of nanographene material. The field profiles of the TE/TM modes are submitted to comprehend these characteristics.

Design of very-large area photonic crystal surface emitting lasers with an all-semiconductor photonic crystal

We report on the design of a photonic crystal surface emitting laser (PCSEL) with an all-semiconductor (InGaP/GaAs) photonic crystal suitable for very-large-area emission and high-power operation. Using coupled-wave theory for PCSELs we model infinite- and finite-size cavity PCSELs and show that a photonic crystal unit cell with square lattice periodicity and a rotated and stretched triangular feature is suitable for the realization of PCSELs with very large areas (1 mm<L < 3 mm for a square cavity of size L × L) while maintaining high mode discrimination between the fundamental laser mode and higher order cavity modes as well as high external efficiency. This was achieved by exploiting a single-lattice photonic crystal unit cell design that minimizes one-dimensional coupling in the photonic crystal, providing a promising alternative to double-lattice PCSELs.

Mechanical Durability of Water Electrolysis Membranes in a Liquid Environment Under Differential Pressure Mode

A perfluorinated sulfonic acid polymer (PFSA) membrane is extensively used in proton exchange membrane（PEM）water electrolyzers for the production of green hydrogen. It is crucial to ensure the membrane’s chemical stability and mechanical durability for long-term performance. PEM is typically assembled with a porous transport layer (PTL), which supports the membrane electrode assembly (MEA), collects current, facilitates water diffusion to catalysts, and must withstand high compressive deformation in a harsh liquid environment over extended periods.It is known that high pressure applied to polymer materials commonly leads to compressive creep. It has been reported that due to such compressive creep deformation, the catalyst layer applied on the PFSA membrane undergoes significant deformation, resulting in the formation of cracks that degrade the performance1-2). Therefore, it is necessary to investigate the creep response of PFSA membranes on PTLs with various diameters and roughness under different pressure modes in order to understand their mechanical durability for long-term performance.In this study, a thermal mechanical analyzer (TMA) was utilized in a hydrated environment with water at 80℃ and 6.2 MPa for over 100 hours. Initially, the PEM was placed on the PTL at 23℃ and immersed in the water chamber. The sample was then heated from 23℃ to 80℃, and once the experimental temperature stabilized at 80℃, a load corresponding to 6.2 MPa was continuously applied to the membrane during measurement. As a result, the membrane thickness rapidly decreased from its initial thickness due to the high pressure, and the membrane deformation gradually slowed down. After over 100 hours of measurement, observations using an optical microscope showed that the membrane in contact with the PTL gradually flowed and penetrated into the pore of the PTL. The relationship between the creep behavior and the penetration of the membrane into the PTL pore, considering various PTLs and membranes, will be presented during the poster session.Reference T, Schuler. et al., J. Electrochem. Soc. 166 (10) F555-F565 (2019)J, Liu. et al., ACS Cent. Sci. DOI: 10.1021/acscentsci.4c00037

Digital twin‐based production logistics resource optimisation configuration method in smart cloud manufacturing environment

AbstractTo adapt to the dynamic, diverse, and personalised needs of customers, manufacturing enterprises face the challenge of continuously adjusting their resource structure. This has led manufacturers to shift towards a smart cloud manufacturing mode in order to build highly flexible production logistics (PL) systems. In these systems, the optimal configuring of PL resources is fundamental for daily logistics planning and vehicle scheduling control, providing necessary resources for the entire PL segment. However, traditional resource configuration methods face limitations, such as incomplete information acquisition, slow response in resource configuration, and suboptimal configuration results, leading to high subsequent operational costs and inefficient logistics transportation. These issues limit the performance of the PL system. To address these challenges, the authors propose a digital twin‐based optimisation model and method for smart cloud PL resources. The approach begins with constructing an optimisation model for the PL system considering the quality of service for a cloud resource is constructed, aiming to minimise the number of logistics vehicles and the total cost of the PL system. Additionally, a DT‐based decision framework for optimising smart cloud PL resources is proposed. Alongside a DT‐based dynamic configuration strategy for smart cloud PL resources is designed. By developing a multi‐teacher grouping teaching strategy and a cross‐learning strategy, the teaching and learning strategies of the standard teaching‐learning‐based optimisation algorithm are improved. Finally, numerical simulation experiments were conducted on the logistics transportation process of a cooperating enterprise, verifying the feasibility and effectiveness of the proposed algorithms and strategies. The findings of this study provide valuable references for the management of PL resources and algorithm design in advanced manufacturing modes.

CoNST: Code Generator for Sparse Tensor Networks

Sparse tensor networks represent contractions over multiple sparse tensors. Tensor contractions are higher-order analogs of matrix multiplication. Tensor networks arise commonly in many domains of scientific computing and data science. Such networks are typically computed using a tree of binary contractions. Several critical inter-dependent aspects must be considered in the generation of efficient code for a contraction tree, including sparse tensor layout mode order, loop fusion to reduce intermediate tensors, and the mutual dependence of loop order, mode order, and contraction order. We propose CoNST, a novel approach that considers these factors in an integrated manner using a single formulation. Our approach creates a constraint system that encodes these decisions and their interdependence, while aiming to produce reduced-order intermediate tensors via fusion. The constraint system is solved by the Z3 SMT solver and the result is used to create the desired fused loop structure and tensor mode layouts for the entire contraction tree. This structure is lowered to the IR of the TACO compiler, which is then used to generate executable code. Our experimental evaluation demonstrates significant performance improvements over current state-of-the-art sparse tensor compiler/library alternatives.

Feature Selection and Optimization of Classifiers for Detection of Credit Card Frauds

Nowadays, in the digital era, the use of credit cards is widespread. People buy and sell goods from home. E-commerce brings a boom to the lifestyle of the people, for the working family, it is a preferable tool to purchase and pay through online mode in order to save the time and visiting hours. However, with the increasing use of credit cards, there have also been a lot of cases of credit card frauds that augmented much in the corona period. Fake credit card transactions significantly affect financial institutions, banks, and clients, whereas fraudsters try to develop new ways of committing fraud daily. To avoid credit card fraud and maintain the credibility of our clients, we need to build a model for credit card detection. There are the various machine learning tools that can be applied in detection of such frauds, these tools can be used to design an enhanced model to detect credit card frauds efficiently. In this view, the study presents a feature selection technique approach of machine learning with different classifiers. The study proposed an optimization algorithm using ‘Firefly’ for feature selection with four different classifiers: neural network, k-nearest neighbors, Support Vector Machine, and decision tree. The performance of all these four classifiers is compared on the basis of accuracy parameter.

Mode Analysis for the Rotating Aerodynamic Disturbance of a Transonic Fan

Abstract The non-synchronous blade vibration induced by a rotating aerodynamic disturbance is encountered for the fan of a turbofan engine working at 65% speedline. To analyze the unsteady characteristics, two methods based on the phase analysis and the compressive sensing (CS) for spatially-undersampled data are proposed and applied to obtain the circumferential mode order of the aerodynamic disturbance, and their performance has been carefully examined at various parameters. It was shown that when there are sufficient probes, i.e., 7–8 in the present study, both the two methods can give a correct prediction to the dominant mode order (the highest is 26 in this work) for all non-engine-order (EO) frequencies. However, if less probes are used, the deterioration of accuracy can be observed for both the two methods and a better performance can be observed for the CS method. In order to suppress the blade vibration, the fan blade is trimmed to alter its solid eigenfrequencies and avoid the resonance, which is proved to be an effective anti-vibration design. The existence of the aerodynamic disturbance after the blade is trimmed also suggests that the vibration is not self-excited but induced by the resonance of the flow excitation and the structure. For the cases with and without vibration, the origin of these non-EO frequencies can be well explained by the spinning mode theory and the interaction between the blade vibration and a high-order blade passing frequency has been observed in this study.

Cultural Constraints in Subtitling and Dubbing Arabic Series into English: A Case Study of the Saudi Series “Alkhallat”

Dubbing and subtitling foreign movies, series, and other audiovisual products have flourished since the invasion of the screens; hence, the translation task between languages and cultures became integral to cope with this vast expansion. The different cultural and religious backgrounds of Arabic and English-speaking cultures complicate the translation of Arabic television series. Therefore, translators should be multicultural and multilingual, especially when working between Western and Eastern cultures. The current study aims to investigate the strategies used by Netflix professional translators to ensure the ideas are culturally conveyed effectively to the intended audience. The research compared the English subtitled and dubbed versions of the Arabic-Saudi series Alkhallat with the original version screened on Netflix. The findings showed that the main subtitling and dubbing strategies that were used were cultural substitution, omission, and paraphrasing. The findings also showed that although the dubbed and subtitled versions employed similar strategies, the wording varied. This variation could be attributed to the differences between spoken and written modes. The current study concludes that translators must understand the source and target cultures and consider the constraints of each AVT mode in order to provide a good quality translation.

A nonlinear manifold model order reduction approach for thermo‐mechanically coupled plasticity

AbstractThis study employs a nonlinear manifold mode order reduction (MOR) approach to address the high computational cost inherent in multi‐physical nonlinear models, which are discretized by the finite element method (FEM), with a particular focus on thermo‐mechanically coupled plasticity under finite strain conditions. Utilizing nodal snapshots obtained from a full‐order simulation, a projection matrix is constructed through singular value decomposition (SVD), facilitating the construction of a reduced system within a lower‐dimensional space. This reduction process entails the multiplication of the discretized residual vector and stiffness matrix by a linear projection matrix, complemented by the incorporation of a nonlinear projection component to ensure accurate reconstruction within the nonlinear part. Subsequently, a comprehensive three‐dimensional benchmark test is conducted to assess the accuracy and efficacy of the reduced‐order model.

Free vibration analysis of rectangular plates resting on an elastic foundation

Abstract Rectangular plate on elastic foundations is a common structural form in aerospace fields, while there still lacks a general analytical method for free vibration analysis of this kind of structure. Thus, the extended separation-of-variable method is used to obtain the analytical free vibration solutions for plates with all kinds of homogeneous boundary conditions. The mode functions are assumed to be in separation-of-variable form, and the natural frequencies of two-direction mode functions are mathematically independent. Then, the free vibration solutions are obtained according to the two-direction boundary conditions. The correctness of the present results is verified via numerical comparisons. Parameter study shows that the elastic foundation significantly affects the flexural vibration behaviors of rectangular plates, and the influence is dependent on boundary conditions and mode orders of rectangular plates.

Impact of Areal Factors on Students’ Travel Mode Choices: A Bayesian Spatial Analysis

A preliminary analysis of the 2018/2019 Austin Travel Survey indicated that most off-campus students in Travis County, TX, tend to use cars rather than more sustainable transportation modes, significantly contributing to traffic congestion and environmental impact. This study aims to analyze the impacts of areal factors, including environmental and transportation factors, on students’ choices of travel mode in order to promote more sustainable transport behaviors. Additionally, we investigate the presence of spatial correlation and unobserved heterogeneity in travel data and their effects on students’ travel mode choices. We have proposed two Bayesian models—a basic model and a spatial model—with structured and unstructured random-effect terms to perform the analysis. The results indicate that the inclusion of spatial random effects considerably improves model performance, suggesting that students’ choices of mode are likely influenced by areal factors often ‘unobserved’ in many individual travel mode choice surveys. Furthermore, we found that the average slope, sidewalk density, and bus-stop density significantly affect students’ travel mode choices. These findings provide insights into promoting sustainable transport systems by addressing environmental and infrastructural factors in an effort to reduce car dependency among students, thereby supporting sustainable urban development.

Unsteady Flow Structure of Rotating Instability in a 1.5-Stage Axial Compressor

Abstract The unsteady flow structure of the rotating instability (RI) in a 1.5-stage axial compressor is investigated through experimental and numerical analyses. In the tested compressor, the total pressure rise of the rotor stagnates at a certain flow coefficient before it increases again toward a lower flowrate in a case involving a wide tip clearance. The RI appears beyond this stagnant point as the compressor is throttled. The RI indicates a gentle hump in the frequency spectra of wall pressure or the flow velocity near the tip in a range of approximately 20–40% of the blade-passing frequency. As the flowrate decreases, the mode order of the RI increases, in contrast to the more commonly reported tendency, while the propagation velocity remains constant. These features are well captured by detached eddy simulation (DES) of the half-annulus model, with which the unsteady flow structure is further investigated. At its onset, RI is formed by the collision of the tip leakage vortex onto the pressure surface of the adjacent blade and subsequent vortex segmentation. This vortex structure spans two blade passages and propagates in the direction opposite to the rotor rotation. As the compressor is throttled, RI becomes more dominated by the circumferential propagation of vortex breakdown of tip leakage vortices, which occur simultaneously among neighboring passages with slight phase differences. The mechanism is discussed in relation to the temporal change in the blade tip loading. The frequency of vortex shedding increases with the reduction in flowrate and thus the increase in the number of RI disturbances.

Numerical analysis of vortex-induced vibration of deepwater drilling riser based on Van der Pol wake oscillator model

Coupled equations of the dynamic model and the Van der Pol wake oscillator model are solved by the central finite difference method for the deepwater drilling riser. The vortex-induced vibration (VIV) response and fatigue life of the riser are calculated and the model validation is performed by comparing with the published experimental and simulation results. The effects of the top tension, current flow velocity, flow velocity profile, internal flow velocity as well as the installation of buoyancy modules on the VIV are discussed. Dynamic response and fatigue life of the riser under In-Line (IL) and Cross-Flow (CF) VIV are preliminarily analyzed. The results show that the VIV of the riser has multiple modes and exhibits a mixed behavior of standing waves and traveling waves. With the increase of top tension and flow velocity profile coefficient, the order of the VIV dominant mode and the peak values of the root mean square (RMS) of VIV displacement decrease, and the fatigue life of the riser is extended. With the increase of current flow velocity, the order of the VIV dominant mode increases and the riser fatigue life decreases. The effect of internal flow velocity on the riser VIV is neglectable. The installation of buoyancy modules can improve the riser stress state and extend the fatigue life. Compared with the CF VIV model, the calculated minimum fatigue life of the riser is extended under the IL and CF coupled VIV model due to the decrease of bending moment and the changing position of fatigue weak point.

Nonlinear dynamic characteristics of smart FG-GPLRC sandwich varying thickness truncated conical shell with internal resonance for first three order modes

This paper examines the 1:1:1 internal resonant nonlinear dynamic characteristic of the simply supported varying thickness functionally graded graphene platelets reinforced composite (FG-GPLRC) smart truncated sandwich conical shell subject to the combined effects of transverse load and in-plane force. The truncated smart sandwich conical shell is composed of an FG-GPLRC varying thickness core and two magneto-electro-elastic face layers, whose material properties and constitutive relations are individually identified by the rule of mixture, improved Halpin-Tsai approach and generalized Hooke's law. Utilizing the first-order shear deformation theory (FSDT), von Karman's geometrical nonlinearity, Hamilton's principle and Galerkin technique, the 3DOF dimensionless nonlinear dynamic formulations for the truncated smart FG-GPLRC conical shell are established. The multiple-scale technique is applied to developing the averaged equations for the truncated smart FG-GPLRC conical shell under combined resonance. The frequency-response and force-response curves, Poincare maps, phase portraits, time history diagrams, bifurcation and maximum Lyapunov exponent diagrams can be portrayed by the nonlinear equation solver and Runge-Kutta approach. The effects of the damping and tuning parameters, transverse and in-plane forces on the 1:1:1 internal resonant nonlinear dynamic characteristic of truncated smart varying thickness FG-GPLRC sandwich conical shell are examined.

High dynamic performance based by sliding mod control of quadrotor MAV

The paper focuses on strong control of high dynamic performance based on the sliding mode in order to control the quadrotor MAV. The model used in the simulation is the Newton-Euler model, and also choose the Mambo Parrot quadrotor parameters, to improve the latter's performance in terms of accuracy and robustness in case the impedance control chosen by the manufacturer needs to be changed. The results of which gave effectiveness and efficiency compared to classical controls PID and sliding mode. High dynamic performance control (HDP) is a type of control system designed to provide the highest level of performance over a wide range of operating conditions. This control is not a regulator but an organizing technique. It uses a prediction-based approach to anticipate rapid variations in system states and disturbances and to generate real-time commands to correct tracking errors and maintain system stability. This approach allows HDP control to achieve high performance while maintaining system stability, even under harsh operating conditions.