bluuebunny/crossref_metadata_2025 huggingface dataset:
Exploring the effects of audience and strategies used by beauty vloggers on behavioural intention towards endorsed brands
Authors: Garg Mukta , Bakshi Apurva
Published: May 2024

Influencer marketing has become a potent and dynamic force in the digital age, changing the face of marketing in a variety of sectors. Even though social media influencers are still important in corporate communication strategies, there are still unresolved issues concerning what exactly makes an influencer powerful and how that influence impacts the behaviour of their followers. This research investigates the role of interactional elements used by beauty vloggers on the purchase intentions of consumers. In addition to the influence of beauty vloggers, there are inherent aspects that impact consumer purchasing behaviour. The present study also examines the impact of audience characteristics in forming consumer attitudes towards beauty vloggers that result in shaping favourable consumer behaviour. The study was carried out on individuals aged 16 to 45 years, who use social platforms regularly. Data obtained from 367 respondents from North India was analysed using structural equation modelling with the SmartPLS software. The outcome of the study demonstrates that interactional elements used by beauty vloggers impact the behaviour of consumers. The results also showed that perceived influence serves as a partial mediator in the relationship between interactional elements and consumers’ purchase intention. Moreover, findings indicate that when consumers hold favourable attitudes towards beauty vloggers, the impact of self-concept and personality congruence enhancement on consumer behaviour is amplified, showcasing the mediating role of consumer attitude. The study’s findings offer insights that can assist industrial marketers and cosmetic company practitioners in strategically selecting influencers to boost sales.
BeM(CO)3− (M = Co, Rh, Ir) and BeM(CO)3 (M = Ni, Pd, Pt): Triply bonded terminal beryllium in zero oxidation state
Authors: Liu Yu-qian , Kalita Amlan J. , Zhang Hui-yu , Cui Li-juan , Yan Bing , Guha Ankur K. , Cui Zhong-hua , Pan Sudip
Published: May 2024

We perform detailed potential energy surface explorations of BeM(CO)3− (M = Co, Rh, Ir) and BeM(CO)3 (M = Ni, Pd, Pt) using both single-reference and multireference-based methods. The present results at the CASPT2(12,12)/def2-QZVPD//M06-D3/def2-TZVPPD level reveal that the global minimum of BeM(CO)3− (M = Co, Rh, Ir) and BePt(CO)3 is a C3v symmetric structure with an 1A1 electronic state, where Be is located in a terminal position bonded to M along the center axis. For other cases, the C3v symmetric structure is a low-lying local minimum. Although the present complexes are isoelectronic with the recently reported BFe(CO)3− complex having a B–Fe quadruple bond, radial orbital-energy slope (ROS) analysis reveals that the highest occupied molecular orbital (HOMO) in the title complexes is slightly antibonding in nature, which bars a quadruple bonding assignment. Similar weak antibonding nature of HOMO in the previously reported BeM(CO)4 (M = Ru, Os) complexes is also noted in ROS analysis. The bonding analysis through energy decomposition analysis in combination with the natural orbital for chemical valence shows that the bonding between Be and M(CO)3q (q = −1 for M = Co, Rh, Ir and q = 0 for M = Ni, Pd, Pt) can be best described as Be in the ground state (1S) interacting with M(CO)30/− via dative bonds. The Be(spσ) → M(CO)3q σ-donation and the complementary Be(spσ) ← M(CO)3q σ-back donation make the overall σ bond, which is accompanied by two weak Be(pπ) ← M(CO)3q π-bonds. These complexes represent triply bonded terminal beryllium in an unusual zero oxidation state.
Rheology of moderated dilute suspensions of star colloids: The shape factor
Authors: Balboa Usabiaga F. , Ellero M.
Published: May 2024

Star colloids are rigid particles with long and slender arms connected to a central core. We show numerically that the colloid shapes control the rheology of their suspensions. In particular, colloids with curved arms and hooks can entangle with neighbor particles and form large clusters that can sustain high stresses. When a large cluster permeates the whole system, the viscosity increases many fold. Contrary to the case of spherical colloids, we observe that these effects are very strong even at moderate volumes fraction over a wide range of Péclet numbers.
Design and experiment of multidimensional and subnanometer stage driven by spatially distributed piezoelectric ceramics
Authors: Zhang Fan , Huang Qiangxian , Zhang Chibin , Cheng Baolin , Cheng Rongjun , Zhang Liansheng , Li Hongli
Published: May 2024

Multidimensional microdriving stage is one of the key components to realize precision driving and high-precision positioning. To meet nanometer displacement and positioning in the fields of micro-/nano-machining and precision testing, a new six-degree-of-freedom microdriving stage (6-DOF-MDS) of multilayer spatially distributed piezoelectric ceramic actuators (PZTs) is proposed and designed. The interior of the 6-DOF-MDS is a hollow design. The flexure hinge is used as the transmission mechanism, and the series–parallel hybrid driving of the corresponding PZTs achieves the microtranslation in the X, Y, and Z directions and the microrotation around the three axes of the microdriving stage, forming a microdisplacement mechanism with high rigidity and simple structure, which can realize the microfeed of 6-DOF. The force–displacement theory and lug boss structure optimization of the 6-DOF-MDS are analyzed, while the strength checking and natural frequency of the 6-DOF-MDS are also simulated by the finite element method. In addition, the real-time motion control system of the 6-DOF-MDS is designed based on Advanced RISC Machines. Through a series of verification experiments, the stroke and resolution results of the 6-DOF-MDS are obtained, where the displacements in the X, Y, and Z directions are 20.72, 20.02, and 37.60 μm, respectively. The resolution is better than 0.68 nm. The rotation angles around X, Y, and Z are 38.96″, 33.80″, and 27.87″, respectively, with an angular resolution of 0.063″. Relevant coupling experiments were also performed in this paper; in the full stroke linear running of X-axis, the maximum coupling displacements of the Y- and Z-axes are 1.04 and 0.17 μm, respectively, with the corresponding coupling rates of ∼5.0% and 0.8%. The maximum coupling angles for the X-, Y-, and Z-axes are 0.33″, 0.14″, and 2.30″, respectively. Considering the coupling of the 6-DOF-MDS, decoupling measures and specific mathematical models have also been proposed. The proposed multidimensional microdriving stage achieves subnanometer resolution and can be used for the precise positioning and attitude control of precision instruments at the nano-/subnanometer level.
Directional motion of discharge filaments pattern in a ratchet dielectric barrier discharge system
Authors: He Yunan , Pan Yuyang , Li Yaohua , Li Cheng , Wei Ting , Zhang Lijia , Dong Lifang
Published: May 2024

The directional motion of the discharge filaments pattern with controllable motion speed is achieved by using a novel dielectric barrier discharge device with a ratcheting asymmetric boundary. It can be observed in a gas mixture of argon and air over a considerably wide parameter range of gas pressure from 12 to 55 kPa and argon content from 0% to 90%. The motion speeds are adjustable with a maximum range of 1.25°/s to 6.25°/s by altering the argon concentration and gas pressure. Notably, the discharge filaments move along the ratchet-tilting direction while maintaining a hexagonal arrangement. The filaments of the hexagonal structure, that is, the main part of the pattern discharge simultaneously as demonstrated by the results of the intensified charge-coupled device measurements. The transverse electric field (parallel to the dielectric plate) simulated by solving the Poisson equation exhibits an asymmetric spatial distribution. A net tangential force from the asymmetric transverse electric field is exerted on the pattern, driving it to a directional motion.
Effects of multiplicative noise on the fractional Hartree equation
Authors: Xie J. , Yang H. , Wang F.
Published: May 2024

This paper is dedicated to radial solutions to the Cauchy problem for the fractional Hartree equation with multiplicative noise. First, we establish a stochastic Strichartz estimate related to the fractional Schrödinger propagator. Local well-posedness for the Cauchy problem is proved by using stochastic and radial deterministic Strichartz estimates. Then, based on Itô’s formula and stopping time arguments, the existence of a global solution is studied. Finally, we investigate the blow-up phenomenon and give a criterion via localized virial estimates.
Double harmonic mode-locking in soliton fiber ring laser acquired through the resonant optoacoustic coupling
Authors: Ribenek V. A. , Itrin P. A. , Korobko D. A. , Fotiadi A. A.
Published: May 2024

Passive harmonic mode-locking of a soliton fiber laser locked to optoacoustic resonance (OAR) in the cavity fiber ensures high-frequency laser operation, high pulse stability, and low timing jitter. However, the pulse repetition rate (PRR) of such lasers is limited to ∼1 GHz for standard fibers due to the available acoustic modes. Here, we address these limitations by demonstrating a soliton fiber laser built from standard fiber components and subjected to double harmonic mode-locking (DHML). As an example, the laser adjusted to operate at the 15th harmonic of its cavity matching the OAR at ∼199 MHz could be driven to operate at a high harmonic of this particular OAR frequency, thus reaching ∼12 GHz. This breakthrough is made possible through controllable optoacoustic interactions in a short, 50 cm segment of unjacketed cavity fiber. We propose that the precise alignment of the laser cavity harmonic and fiber acoustic modes leads to a long-lived narrow-band acoustic vibration. This vibration sets the pace for the pulses circulating in the cavity by suppressing modes that do not conform to the Vernier principle. The surviving modes, equally spaced by the OAR frequency, in cooperation with the gain depletion and recovery mechanism, facilitate the formation of stable high-frequency pulse sequences, enabling DHML. In this process, the OAR rather than the laser cavity defines the elementary step for laser PRR tuning. Throughout the entire PRR tuning range, the soliton fiber laser exhibits enhanced stability, demonstrating supermode suppression levels better than ∼40 dB and picosecond pulse timing jitter.
Weak signal detection technique based on Durbin–Watson test and one-bit sampling
Authors: Zhao Xiru , Hu Jiadong , Wu Kenan , Xia Haiyun , Yu Daihao
Published: May 2024

Correlation-based detection techniques are widely used in the weak periodic signal detection field. Traditionally, they are based on extracting the correlation of a weak signal from noise. Considering the impact of a weak signal on the randomness of background noise, this article takes the opposite approach and proposes a weak signal detection technique based on the Durbin–Watson (DW) test and one-bit sampling, detecting the weak signal due to the extent to which the randomness of noise is affected. The randomness of noise is analyzed through the DW test, which is a method for detecting the randomness of data sequences through first-order autocorrelation. One-bit sampling is adopted to reduce the complexity of the sampling circuit and data processing algorithm. The effectiveness of the DW test in the situation of one-bit sampling is demonstrated through simulation and analysis. Simulation results show that the proposed technique is capable of detecting weak sinusoidal and square-wave signals with a signal-to-noise ratio (SNR) above −30 dB, and the frequency or SNR of a weak signal can be further estimated based on mutual constraints. The measured results confirm the capability. In addition, the factors of coherent sampling, noise bandwidth, and comparator threshold that influence the performance of the proposed technique are simulated and discussed in detail.
Experimental study on three-dimensional blade designs in an aggressive compressor transition duct
Authors: An Guangfeng , Fan Zhu , Yu Xianjun , Liu Baojie
Published: May 2024

The increasing performance requirements for aero-engines necessitate the integrated design of compressor transition ducts with upstream components to reduce the axial length of the engine. This paper presents an experimental investigation of three-dimensional (3D) blade designs within an aggressive compressor transition duct integrated with the upstream stator. The aim is to reduce the total pressure loss and decrease the radial distortion of the flow field at the outlet of the transition duct, thus providing better inflow conditions for the high-pressure compressor. Detailed measurements of the internal flow field were conducted under both near stall (NS) and design (DE) conditions for three 3D blades. The results showed that in the downward path, adopting the 3D blades with positive dihedral and forward sweep contributed to mitigating the stator hub corner stall under the NS condition. Under the same operating conditions, enhanced kinetic energy at the stator root improved the spanwise uniformity of the transition duct outlet profile, while also increasing the anti-separation capability of the downstream hub boundary layer. The corner vortex at the stator root could enhance momentum mixing between the downstream hub boundary layer and the mainstream, thereby providing stronger separation resistance for the hub boundary layer under the NS condition. Compared to the baseline stators, the optimized 3D stators reduced system total pressure loss by 24% under the NS condition, while maintaining essentially unchanged total pressure loss under the DE condition.
Magnetic field influence on Casson fluid flow in rotating convection
Authors: Bixapathi Sapavat , Babu A. Benerji
Published: May 2024

The stability of buoyant flow in an infinite extended vertical fluid layer bounded by impermeable conducting isothermal rigid walls, known as magnetic field influence on Casson fluid flow in rotating convection, is investigated. A system of governing equations (Navier–Stokes, heat, and induction ones) is solved with isothermal rigid boundary conditions. When the majority of electrically conducting fluids are extremely small, the stability of governing equations can be simplified by taking the smallness of magnetic Prandtl number into account. In linear stability, the Chebyshev collocation method is used to solve numerically the system of eigenvalue problems. The Casson fluid parameter, Chandrasekhar number, magnetic Prandtl number, and Taylor number all have destabilizing effects on the system's basic velocity and basic magnetic field, resulting in instability. The critical Rayleigh number (Rc), critical wave number (ac), and critical wave speed (cc) are calculated using the influence of governing parameters. The Casson fluid parameter and magnetic Prandtl number were found to stabilize stationary disturbances in neutral stability curves.
Wolfes model aka
G2/I6-rational integrable model: g(2), g(3) hidden algebras and quartic polynomial algebra of integrals
Authors: Lopez Vieyra Juan Carlos , Turbiner Alexander V.
Published: May 2024

One-dimensional 3-body Wolfes model with 2- and 3-body interactions also known as G2/I6-rational integrable model of the Hamiltonian reduction is exactly-solvable and superintegrable. Its Hamiltonian H and two integrals I1,I2, which can be written as algebraic differential operators in two variables (with polynomial coefficients) of the 2nd and 6th orders, respectively, are represented as non-linear combinations of g(2) or g(3) (hidden) algebra generators in a minimal manner. By using a specially designed MAPLE-18 code to deal with algebraic operators it is found that (H,I1,I2,I12≡[I1,I2]) are the four generating elements of the quartic polynomial algebra of integrals. This algebra is embedded into the universal enveloping algebra g(3). In turn, 3-body/A2-rational Calogero model is characterized by cubic polynomial algebra of integrals, it is mentioned briefly.
Deep learning path-like collective variable for enhanced sampling molecular dynamics
Authors: Fröhlking Thorben , Bonati Luigi , Rizzi Valerio , Gervasio Francesco Luigi
Published: May 2024

Several enhanced sampling techniques rely on the definition of collective variables to effectively explore free energy landscapes. The existing variables that describe the progression along a reactive pathway offer an elegant solution but face a number of limitations. In this paper, we address these challenges by introducing a new path-like collective variable called the “deep-locally non-linear-embedding,” which is inspired by principles of the locally linear embedding technique and is trained on a reactive trajectory. The variable mimics the ideal reaction coordinate by automatically generating a non-linear combination of features through a differentiable generalized autoencoder that combines a neural network with a continuous k-nearest neighbor selection. Among the key advantages of this method is its capability to automatically choose the metric for searching neighbors and to learn the path from state A to state B without the need to handpick landmarks a priori. We demonstrate the effectiveness of DeepLNE by showing that the progression along the path variable closely approximates the ideal reaction coordinate in toy models, such as the Müller-Brown potential and alanine dipeptide. Then, we use it in the molecular dynamics simulations of an RNA tetraloop, where we highlight its capability to accelerate transitions and estimate the free energy of folding.
Avoiding pitfalls in molecular simulation of vapor sorption: Example of propane and isobutane in metal–organic frameworks for adsorption cooling applications
Authors: Formalik Filip , Chen Haoyuan , Snurr Randall Q.
Published: May 2024

This study introduces recommendations for conducting molecular simulations of vapor adsorption, with an emphasis on enhancing the accuracy, reproducibility, and comparability of results. The first aspect we address is consistency in the implementation of some details of typical molecular models, including tail corrections and cutoff distances, due to their significant influence on generated data. We highlight the importance of explicitly calculating the saturation pressures at relevant temperatures using methods such as Gibbs ensemble Monte Carlo simulations and illustrate some pitfalls in extrapolating saturation pressures using this method. For grand canonical Monte Carlo (GCMC) simulations, the input fugacity is usually calculated using an equation of state, which often requires the critical parameters of the fluid. We show the importance of using critical parameters derived from the simulation with the same model to ensure internal consistency between the simulated explicit adsorbate phase and the implicit bulk phase in GCMC. We show the advantages of presenting isotherms on a relative pressure scale to facilitate easier comparison among models and with experiment. Extending these guidelines to a practical case study, we evaluate the performance of various isoreticular metal–organic frameworks (MOFs) in adsorption cooling applications. This includes examining the advantages of using propane and isobutane as working fluids and identifying MOFs with a superior performance.
Large magnetoresistance and nontrivial Fermi surface topology in quasi-one-dimensional Ta2PdSe6
Authors: Wang Yuanyuan , Chen Zheng , Tu Wenqian , Zhu Xiangde , Lu Wenjian , Ning Wei , Tian Mingliang
Published: May 2024

We report the experimental investigation of quasi-one-dimensional (quasi-1D) Ta2PdSe6 single crystals by magnetotransport measurements under high magnetic fields up to 31 T. The crystals show large unsaturated magnetoresistance up to (1.8 × 105%) under 31 T at 1.6 K, accompanied by remarkable resistivity oscillations. The analysis of quantum oscillations reveals the existence of five Fermi pockets, consistent with theoretical calculations. Furthermore, our investigation suggested that band structure is modified by the electron correlations in Ta2PdSe6, which may provide a platform for exploring the interplay between electron effects and topological properties in quasi-1D materials.
Microdroplet formation of water and alumina nanofluid in a T-junction microchannel
Authors: Governo A. F. L. , Murshed S. M. S. , Semião V.
Published: May 2024

A scarcity of studies about nanofluids’ utilization in droplet formation inside microdevices currently hovers in the literature although potential applications of nanoparticles in a microfluidic environment are foreseen. For this purpose, experimentally assessing both nanofluid and microdroplet characteristics is fundamental. This work reports a series of experimental tests on the microdroplet formation of distilled water (DIW) and DIW-based aluminum oxide (Al2O3) nanofluid in a microfluidic T-junction. While water and nanofluid are used as the dispersed phase, mineral oil is used as the continuous phase. Microdroplet formation in the squeezing, transitional, and dripping regimes is characterized and scaling laws for the non-dimensional droplet volumes are presented. The effects of flow rate, capillary number, microchannel aspect ratio, and nanoparticle concentration are investigated. The addition of Al2O3 nanoparticles to the water is observed to have a major impact in the transitional regime (up to 40% increase), whereas in the dripping regime its influence is lower, with less than 10% difference. This was attributed to the nanofluid's enhanced interfacial tension and viscosity compared to the DIW, as well as possible adsorption at the surface.
Regulating turbulent separation by surface microstructures on a blunt plate
Authors: Du Zengzhi , Gao An-Kang , You Chenxi , Chen Guo-Qing , Liu Yongze , Li Hongyuan , Lv Pengyu , Duan Huiling
Published: May 2024

Microstructured surfaces can induce secondary flow and regulate flow structures of the turbulent separation flow. However, the mechanism governing the relationship between the microstructure size and the characteristic flow size remains unclear. In this study, the separated flow over a blunt flat plate with surface microstructures is studied using time-resolved particle image velocimetry experiments and implicit large-eddy simulations for the plate-thickness-based Reynolds number from 5.08×103 to 1.31×104. The ratio of the height of microstructures to the plate thickness (h/d) ranges from 0.01 to 0.1. Combining experimental and numerical results, the relationships between the separation bubble size and the microstructure size under different Reynolds numbers exhibit similarity when normalized by the separation bubble size of the smooth plate. The dimensionless separation bubble size decreases when the microstructure height increases and large microstructures (h/d = 0.1) exhibit good performance on reducing the flow separation. Near the leading edge, the distortion of two-dimensional vortices and the generation of three-dimensional hairpin vortices are promoted by the first several rows of large microstructures. Additionally, in the main separation region, secondary positive spanwise vortices emerge from large microstructures. Subsequently, the secondary vortices lift up and evolve into streamwise vortices. The characteristic scale of secondary vortices is represented by a significant peak in the spectra of spanwise wavenumbers, which is of the same magnitude as the height of large microstructures. Furthermore, increasing the microstructure height weakens the streamwise correlation of the flow, and the characteristic scale of the correlation is comparable to the height of large microstructures.
Physics-constrained robust learning of open-form partial differential equations from limited and noisy data
Authors: Du Mengge , Chen Yuntian , Nie Longfeng , Lou Siyu , Zhang Dongxiao
Published: May 2024

Unveiling the underlying governing equations of nonlinear dynamic systems remains a significant challenge. Insufficient prior knowledge hinders the determination of an accurate candidate library, while noisy observations lead to imprecise evaluations, which in turn result in redundant function terms or erroneous equations. This study proposes a framework to robustly uncover open-form partial differential equations (PDEs) from limited and noisy data. The framework operates through two alternating update processes: discovering and embedding. The discovering phase employs symbolic representation and a novel reinforcement learning (RL)-guided hybrid PDE generator to efficiently produce diverse open-form PDEs with tree structures. A neural network-based predictive model fits the system response and serves as the reward evaluator for the generated PDEs. PDEs with higher rewards are utilized to iteratively optimize the generator via the RL strategy and the best-performing PDE is selected by a parameter-free stability metric. The embedding phase integrates the initially identified PDE from the discovering process as a physical constraint into the predictive model for robust training. The traversal of PDE trees automates the construction of the computational graph and the embedding process without human intervention. Numerical experiments demonstrate our framework's capability to uncover governing equations from nonlinear dynamic systems with limited and highly noisy data and outperform other physics-informed neural network-based discovery methods. This work opens new potential for exploring real-world systems with limited understanding.
Quantification of chirality based on electric toroidal monopole
Authors: Inda A. , Oiwa R. , Hayami S. , Yamamoto H. M. , Kusunose H.
Published: May 2024

Chirality ubiquitously appears in nature; however, its quantification remains obscure owing to the lack of microscopic description at the quantum-mechanical level. We propose a way of evaluating chirality in terms of the electric toroidal monopole, a practical entity of time-reversal even pseudoscalar (parity-odd) objects reflecting relevant electronic wave functions. For this purpose, we analyze a twisted methane molecule at the quantum-mechanical level, showing that the electric toroidal monopoles become a quantitative indicator for chirality. In the twisted methane, we clarify that the handedness of chirality corresponds to the sign of the expectation value of the electric toroidal monopole and that the most important ingredient is the modulation of the spin-dependent imaginary hopping between the hydrogen atoms, while the relativistic spin–orbit coupling within the carbon atom is irrelevant for chirality.
HISOL: High-energy soliton dynamics enable ultrafast far-ultraviolet laser sources
Authors: Brahms Christian , Travers John C.
Published: May 2024

Ultrafast laser sources in the far ultraviolet (100–300 nm) have been the subject of intense experimental efforts for several decades, driven primarily by the requirements of advanced experiments in ultrafast science. Resonant dispersive wave emission from high-energy laser pulses undergoing soliton self-compression in a gas-filled hollow capillary fiber promises to meet several of these requirements for the first time, most importantly by combining wide-ranging wavelength tuneability with the generation of extremely short pulses. In this Perspective, we give an overview of this approach to ultrafast far-ultraviolet sources, including its historical origin and underlying physical mechanism, the state of the art and current challenges, and our view of potential applications both within and beyond ultrafast science.
Understanding the microstructure evolution of carbon-doped Sb2Te3 phase change material for high thermal stability memory application
Authors: Zhang Mengyu , Wang Ruobing , Zou Xixi , Song Sannian , Bao Yun , Wu Liangcai , Song Zhitang , Zhou Xilin
Published: May 2024

The Sb2Te3 phase change material shows a growth-dominated crystallization mechanism with fast phase transition but poor thermal stability of the amorphous state. This work investigated the effects of carbon doping on the thermal stability, microstructure, and electrical properties of the Sb2Te3 material. The 10-year data retention temperature of the material increased to ∼147.3 °C and the size of the grains was limited to ∼10 nm by carbon doping. The formation of the C cluster upon crystallization was found at the grain boundaries, which was accelerated as the temperature increased due to the break of the Sb–C bonds. The memory device based on the carbon-doped Sb2Te3 material exhibited a switching speed of 15 ns and an endurance of ∼105 cycles with a resistance ratio of more than two orders of magnitude. This work suggests that the carbon-doped Sb2Te3 material is a promising candidate for memory applications that require high thermal stability, fast speed, and high endurance.
Integrated thin-film lithium niobate electro-optic frequency comb for picosecond optical pulse train generation
Authors: Wang Xuanhao , Li Zhengkai , Chen Junji , Shang Chenglin , Zhang Zhiyao , Li Heping , Liu Yong , Zeng Cheng , Xia Jinsong
Published: May 2024

In recent years, high-performance thin-film lithium niobate (TFLN) electro-optic (EO) modulators boost the fast development of highly integrated, low loss, and large comb spacing EO frequency combs. Furthermore, ultra-short optical pulse trains (USOPTs) can be generated by the temporal domain compression of the optical frequency comb, which play an essential role in photonic sampling analog-to-digital conversion. Here, we demonstrate a flat and broadband EO frequency comb based on a packaged TFLN chip including a monolithic integrated intensity modulator, a phase modulator, and edge couplers. The 25 comb lines with a power fluctuation less than 3 dB are presented successfully. Moreover, we obtain a 10 GHz repetition rate USOPT, the pulse width of which is compressed to 2.67 ps. Our device may find its applications in the fields of ultrafast measurement, wavelength-division-multiplexing optical communication, or high-precision photonic sampling.
Experimental study on the coupled flow field and thrust characteristics of tail cavity and jet
Authors: Wang Guilin , Wang Cong , Zhao Jiazhen , Xu Haiyu , Wang Wenjun
Published: May 2024

During the launch process of underwater vehicles, a tail cavity is formed at the bottom, which plays a crucial role in the engine ignition stage. The flow state within this tail cavity significantly impacts the engine's operational efficiency. Moreover, the evolution of the tail cavity and jet coupling, along with hydrodynamic characteristics, influences the motion attitude of the vehicle. This article delves into the effects of initial tail cavity length, Froude number, and pressure ratio on cavity morphology and hydrodynamic characteristics, utilizing water tunnel experiments to explore these dynamics at the vehicle's bottom. The experimental findings suggest that while the length of the initial tail cavity influences the jet's coupling mode, it does not significantly affect the cavity's ultimate morphological evolution. A larger initial cavity scale correlates with a lower initial pressure peak following nozzle activation; similarly, an increase in the Froude number leads to a decrease in the initial pressure peak. When the cavity morphology remains intact, the pressure pulsation amplitude and frequency are relatively low. In contrast, partially broken cavities and pulsating foam cavities differ in morphological structure and peak internal pressure oscillations, though their pressure pulsation frequencies are similar. During the initial phase of nozzle activation, the thrust produced by the nozzle plays a more significant role than the bottom thrust. Notably, in the initial phase of nozzle activation, the nozzle-generated thrust is more influential than the bottom thrust. The thrust pulsations from pulsating foam cavities are especially strong, with peak values surpassing the initial peak thrust. These insights offer a new insight on the dynamic behavior of underwater vehicles, crucial for refining engine startup strategies.
Numerical study of heat transfer enhancement by using protrusions in curved pin-fin arrays
Authors: Yang Ziyang , Luo Lei , Cheng Hao , Yan Han , Du Wei , Zhou Xun
Published: May 2024

The trailing edge of a turbine blade constantly faces the harshest conditions, and pin fin is usually equipped for internal cooling channel of trailing edge to augment heat transfer. The present study aims to explore the impact of various protrusion positions on the heat transfer efficiency of a hybrid channel, incorporating protrusions and curved pin fins, under both stationary and rotational conditions. Three protrusion positions (front, middle, and behind) are studied for the range of Ro from 0 to 0.5. The baseline of the curved pin fins channel without protrusions is considered. This study is based on the numerical method of the realizable k-ε turbulence model for calculation. Numerical calculations reveal that arranging protrusions within the curved pin-fin channel can significantly enhance the overall heat transfer performance. Protrusions of front get the best improvement 15.47% in thermal performance factors under stationary condition. Under rotating condition, the arrangement of protrusions also brings improvement of the Nu number on endwalls from 5.32% to 10.74%.
Research on the drag reduction of high-speed train based on bottom two-multistage wing deflector
Authors: Jiang Chen , Li Yansong , Long Jinlan , Tang Xin , Gao Guangjun , Eze Franklin
Published: May 2024

To address the challenge of reducing aerodynamic drag while further enhancing the speed of high-speed trains, this research employs the concept of flow control for the bottom parts and draws inspiration from the front wings of Formula 1 (F1) race cars. Three kinds of two-multistage wing deflectors are designed and systematically analyzed by unsteady Reynolds-averaged Navier–Stokes (URANS) turbulent model. The most suitable design is determined by the single bogie model with a simplified train body. Using the improved delayed detached eddy simulation method, the aerodynamic drag of 1:8 three-car train models with or without two-multistage wing deflector is studied at different operational speeds. The results present the total drag reduction is higher at higher speeds. The reductions of 4.26%, 3.92%, 3.63%, and 3.49% are obtained at the operating speeds of 400, 350, 300, and 200 km/h, respectively. The two-multistage wing deflector desirably improves the flow structure at the bottom of the train, which leads to the reduction of aerodynamic drag and a corresponding reduction in the positive pressure zones within the bogie area. Furthermore, the deflector restricts shedding vortices, effectively narrowing the interference range of airflow under the train, which will provide a potential drag reduction method for the next generation high-speed train.
Dynamic response of a homogeneous hygrothermoelastic slab sandwiched between elastic half-spaces
Authors: Adel M. , Ailawalia Praveen , Salhotra Sandeep , Lotfy Kh.
Published: May 2024

In the current study, the authors discuss a homogeneous hygrothermoelastic slab of thickness 2h sandwiched between two similar elastic half-spaces. The hygrothermoelastic slab is subjected to a mechanical source of constant magnitude. The source is applied along the interface of the slab and upper elastic half-space. The analytical expressions of the components of displacement, stresses, moisture concentration, and temperature field are obtained by the normal mode analysis technique. The analytical results are used to solve the problem numerically by taking a wood slab as a porous material. The graphical results elaborate the effect of the thickness of a slab on the physical quantities. The problem of hygrothermoelastic layers sandwiched between elastic half-spaces is a novel idea, which finds its applications in various engineering models. The results found are interesting in the context of the problem. It is observed that the thickness of a hygrothermoelastic slab affects the deformation in the medium and the values of physical quantities decrease with an increase in the thickness of the slab.
Electroosmotic flow in graphene nanochannels considering steric effects
Authors: Wu Zhilin , Liu Yongbo , Liu Guanting
Published: May 2024

Graphene nanochannels are excellent channels for electroosmotic flow (EOF) due to their larger slip length. In this study, the fully developed EOF in graphene nanochannels is investigated numerically, where the influence of surface charge mobility on the Navier-slip boundary conditions and the influence of steric effect on the electric potential distribution are considered. In addition, an analytical solution is provided for the scenario with low zeta potential. Detailed investigations are conducted on the impact of slip length, surface charge density, surface charge mobility, effective ion size, solution concentration, and channel height on velocity profiles. The findings indicate that the velocity increases with slip length, surface charge density, and effective ion size. Yet, accounting for surface charge mobility (αs = 0.815) leads to a reduction in slip velocity. It is noteworthy that our investigation focuses on quantifying the velocity decline due to surface charge mobility, as well as the velocity enhancement resulting from the steric effect. By adjusting parameters, such as channel height, bare slip length, and solution concentration, we achieve a maximum velocity increase of approximately 48%. These insights are valuable for optimizing the design of efficient electro-osmotic pumping systems.
Cropping calendar, agroclimatic and agroecological zoning for rainfed maize (Zea mays L.) under different rainfall scenarios in a semi-arid region of Brazil
Authors: Nogueira Danilo Batista , Sousa Alfredo Mendonça de , Silva Alexsandro Oliveira da , Costa Bruno Ricardo Silva , Arruda Rafaela da Silva , Putti Fernando Ferrari
Published: May 2024

Context The productivity of crops is influenced by the available net water balance, which relies on a complex interplay of edaphic and climatic factors. In this sense, rainfall is the leading water input for crop growth and yield, especially in water-scarce regions under semi-arid climates worldwide. Aims This study aimed to define the optimum cropping calendar and the agroclimatic and agroecological zones for rainfed maize in the state of Ceará, which is predominantly located within the Brazilian semi-arid region, assuming different rainfall scenarios. Methods We considered the subdivision of the study area into eight homogeneous precipitation regions according to the regional rainfall pattern. The climatic water balance for each region over two decades was calculated from historical weather data series, assuming three rainy scenarios: dry, regular, and rainy. The agroclimatic zoning was defined through the crop water balance results, soil classification, land use and occupation, slope and temperature, weighted through a multi-criteria decision analysis based on the Analytic Hierarchy Process. Key results The recommended planting period was broader in rainy conditions. However, there may be some dry spells between two 10-day intervals of the calendar, which impair plant growth depending on their intensity. For the dry scenario, the agroclimatic zoning showed that the marginal water deficiency covered 96.55% of the study area. Conclusions Rainfed maize cultivated under the semi-arid climate of Ceará state is viable in rainy conditions, partially restricted in regular years, and not recommended in dry years. Implications This study emphasises the importance of climate monitoring in effective planning for rainfed maize cultivation in semi-arid regions.
Extreme elevational migration spurred cryptic speciation in giant hummingbirds
Authors: Williamson Jessie L. , Gyllenhaal Ethan F. , Bauernfeind Selina M. , Bautista Emil , Baumann Matthew J. , Gadek Chauncey R. , Marra Peter P. , Ricote Natalia , Valqui Thomas , Bozinovic Francisco , Singh Nadia D. , Witt Christopher C.
Published: May 2024

The ecoevolutionary drivers of species niche expansion or contraction are critical for biodiversity but challenging to infer. Niche expansion may be promoted by local adaptation or constrained by physiological performance trade-offs. For birds, evolutionary shifts in migratory behavior permit the broadening of the climatic niche by expansion into varied, seasonal environments. Broader niches can be short-lived if diversifying selection and geography promote speciation and niche subdivision across climatic gradients. To illuminate niche breadth dynamics, we can ask how “outlier” species defy constraints. Of the 363 hummingbird species, the giant hummingbird (
Patagona gigas
) has the broadest climatic niche by a large margin. To test the roles of migratory behavior, performance trade-offs, and genetic structure in maintaining its exceptional niche breadth, we studied its movements, respiratory traits, and population genomics. Satellite and light-level geolocator tracks revealed an >8,300-km loop migration over the Central Andean Plateau. This migration included a 3-wk, ~4,100-m ascent punctuated by upward bursts and pauses, resembling the acclimatization routines of human mountain climbers, and accompanied by surging blood-hemoglobin concentrations. Extreme migration was accompanied by deep genomic divergence from high-elevation resident populations, with decisive postzygotic barriers to gene flow. The two forms occur side-by-side but differ almost imperceptibly in size, plumage, and respiratory traits. The high-elevation resident taxon is the world’s largest hummingbird, a previously undiscovered species that we describe and name here. The giant hummingbirds demonstrate evolutionary limits on niche breadth: when the ancestral niche expanded due to evolution (or loss) of an extreme migratory behavior, speciation followed.
The
GPAT4
/
6
/
8
clade functions in
Arabidopsis
root suberization nonredundantly with the
GPAT5/7
clade required for suberin lamellae
Authors: Gully Kay , Berhin Alice , De Bellis Damien , Herrfurth Cornelia , Feussner Ivo , Nawrath Christiane
Published: May 2024

Lipid polymers such as cutin and suberin strengthen the diffusion barrier properties of the cell wall in specific cell types and are essential for water relations, mineral nutrition, and stress protection in plants. Land plant–specific glycerol-3-phosphate acyltransferases (GPATs) of different clades are central players in cutin and suberin monomer biosynthesis. Here, we show that the
GPAT4
/
6
/
8
clade in
Arabidopsis thaliana
, which is known to mediate cutin formation, is also required for developmentally regulated root suberization, in addition to the established roles of
GPAT5/7
in suberization. The
GPAT5
/
7
clade is mainly required for abscisic acid–regulated suberization. In addition, the
GPAT5
/
7
clade is crucial for the formation of the typical lamellated suberin ultrastructure observed by transmission electron microscopy, as distinct amorphous globular polyester structures were deposited in the apoplast of the
gpat5 gpat7
double mutant, in contrast to the thinner but still lamellated suberin deposition in the
gpat4 gpat6 gpat8
triple mutant. Site-directed mutagenesis revealed that the intrinsic phosphatase activity of GPAT4, GPAT6, and GPAT8, which leads to monoacylglycerol biosynthesis, contributes to suberin formation. GPAT5/7 lack an active phosphatase domain and the amorphous globular polyester structure observed in the
gpat5 gpat7
double mutant was partially reverted by treatment with a phosphatase inhibitor or the expression of phosphatase-dead variants of
GPAT4
/
6
/
8.
Thus, GPATs that lack an active phosphatase domain synthetize lysophosphatidic acids that might play a role in the formation of the lamellated structure of suberin. GPATs with active and nonactive phosphatase domains appear to have nonredundant functions and must cooperate to achieve the efficient biosynthesis of correctly structured suberin.
The modern human aryl hydrocarbon receptor is more active when ancestralized by genome editing
Authors: Helmbrecht Nelly , Lackner Martin , Maricic Tomislav , Pääbo Svante
Published: May 2024

The aryl hydrocarbon receptor (AHR) is a transcription factor that has many functions in mammals. Its best known function is that it binds aromatic hydrocarbons and induces the expression of cytochrome P450 genes, which encode enzymes that metabolize aromatic hydrocarbons and other substrates. All present-day humans carry an amino acid substitution at position 381 in the AHR that occurred after the divergence of modern humans from Neandertals and Denisovans. Previous studies that have expressed the ancestral and modern versions of AHR from expression vectors have yielded conflicting results with regard to their activities. Here, we use genome editing to modify the endogenous
AHR
gene so that it encodes to the ancestral, Neandertal-like AHR protein in human cells. In the absence of exogenous ligands, the expression of AHR target genes is higher in cells expressing the ancestral AHR than in cells expressing the modern AHR, and similar to the expression in chimpanzee cells. Furthermore, the modern human AHR needs higher doses of three ligands than the ancestral AHR to induce the expression of target genes. Thus, the ability of AHR to induce the expression of many of its target genes is reduced in modern humans.
Facilitation for non-identical cognates in L3
Authors: Lijewska Agnieszka , de Louw Robertus
Published: May 2024

In the present study we aimed to obtain with trilinguals the cognate inhibitory effects reported earlier for bilingual speakers who performed L2 lexical decision tasks (LDTs) with non-identical cognates and controls. To that end, Polish–English–Dutch trilinguals performed two LDTs in their L3. In Experiment 1, the stimuli included two types of double non-identical cognates Polish–Dutch (e.g.,SMAK–SMAAK), and English–Dutch (e.g.,BUTTER–BOTER) as well as matched non-cognate Dutch controls (e.g.,JASJE). In Experiment 2, we tested triple non-identical cognates shared across Polish, English and Dutch (e.g.,GRUPA–GROUP–GROEP) and Dutch controls (e.g.,BROEK). We failed to find the bilingual inhibitory effects. In contrast, significant facilitation for English–Dutch and for Polish–English–Dutch cognates was found, even though no identical cognates were used. However, Polish–Dutch cognates yielded null results. The current findings emphasize the influence of the levels of form similarity on the observed cognate effects and point to the important role of stimulus list composition in cognate processing.
Introducing regression discontinuity design to applied linguistics
Authors: Sasaki Miyuki , Higuchi Yuki , Nakamuro Makiko , Roever Carsten , Yashima Tomoko
Published: May 2024

This report presents regression discontinuity design (RDD) as a powerful analytical tool for use in applied
linguistics showcased through our study of the impact of Japanese government study-abroad (SA) scholarships. RDD enables the
estimation of causal effects in scenarios where a true experiment is not feasible by exploiting a naturally occurring cutoff point
for treatment assignment. Because RDD may be novel to most readers in applied linguistics, this report provides a detailed
step-by-step explanation of the standard RDD procedures our study exemplifies. The results section is crafted to reflect the
conventional presentation style of RDD findings. Furthermore, the report’s concluding segment suggests scenarios within SA-related
language learning research that could benefit from RDD application by enhancing the nuanced and precise interpretation of data in
applied linguistics contexts.