bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design and experimental evaluation of a data‐driven PID controller using cerebellar memory
Authors: Li Zhifeng , Hiraoka Kei , Yamamoto Toru 
Published: June 2024

AbstractIn industrial process control, the proportional–integral–derivative (PID) control scheme is well‐recognized and widely utilized. However, due to the distinctive characteristics of real systems, their control design primarily aims at achieving optimal production performance, constrained by uncertainty and variations. This paper initially discusses a database‐driven PID (DD‐PID) control scheme that was previously proposed. This scheme combines the DD‐PID with the cerebellar model articulation control to minimise computational and memory requirements for industrial application. Subsequently, a hydraulic system is introduced, detailing its characteristics and control necessities. Furthermore, both the DD‐PID and the proposed cerebellar model articulation control memory‐based DD‐PID control schemes are implemented and evaluated through experimental examples on a hydraulic system. Lastly, as a practical validation of the theoretical approach, a quantitative assessment compares the two methods, discussing the practicality and efficacy of the proposed scheme in reducing computation and memory consumption.
An improved double‐vector model predictive control strategy for four‐switch three‐phase inverter‐fed permanent magnet synchronous motor based on visualisation analysis considering DC voltage pulsation
Authors: Wang Pengshuai , Niu Feng , Guo Leilei , Huang Shaopo , Chu Zhiyue 
Published: June 2024

AbstractTo address the problem of considerable current distortions in traditional single‐vector model predictive control (MPC) method for four‐switch three‐phase inverter (FSTPI)‐fed permanent magnet synchronous motor, a double‐vector MPC scheme has been studied. However, it still lacks a sufficient theoretical foundation, causing doubts about its effectiveness. To perfect this deficiency, a novel visualisation analysis scheme considering DC voltage pulsation is presented to demonstrate the validity of the traditional double‐vector MPC method for FSTPI. The analysis results reveal for the first time that the traditional double‐vector MPC method is not always superior to the single‐vector method as there is no zero voltage vector for FSTPI. So, a new virtual voltage vector is defined to compensate the deteriorated control performance caused by the absence of zero voltage vectors, based on which an improved double‐vector MPC method is further put forward to reduce the current ripples. Then, the presented visualisation analysis is adopted to demonstrate the validity of the improved MPC strategy under pulsating DC voltage conditions. Finally, a new voltage sector division technology is further put forward to simplify the implementation steps of the presented method. Contrastive experimental studies demonstrate the availability of the improved MPC strategy.
Intelligent stability monitoring and improvement of grid‐connected converter under weighted average control
Authors: Qiu Yuan , Wang Yanbo , Tian Yanjun , Chen Zhe 
Published: June 2024

AbstractThis article presents an intelligent stability monitoring and improvement method for the grid‐connected converter system. The model of grid‐connected converter, based on the weighted average current feedback (WACF) and weighted average voltage feedforward (WAVF) control, is first established. Then, the time‐varying grid impedance and parameter perturbation of LCL‐filter are precisely identified by artificial neural network (ANN) module in real time. Furthermore, the control parameters are adaptively tuned by certain rules based on the predicted parameters to increase the high‐frequency stability margin of converter system. Simulation and experimental results are given to validate the proposed identification and parameter tuning method. The proposed method is able to monitor the real‐time operation state of the grid‐connected converter and improve the self‐adaptivity of the grid‐connected converter system against parameter perturbation.
Dust evolution during a protostellar collapse: Influence on the coupling between the neutral gas and magnetic field
Authors: Vallucci-Goy V. , Lebreuilly U. , Hennebelle P. 
Published: June 2024

Context. The extent of the coupling between the magnetic field and the gas during the collapsing phase of star-forming cores is strongly affected by the dust size distribution, which is expected to evolve by means of coagulation, fragmentation, and other collision outcomes.
Aims. We aim to investigate the influence of key parameters on the evolution of the dust distribution, as well as on the magnetic resistivities during protostellar collapse.
Methods. We performed a set of collapsing single-zone simulations with shark. The code computes the evolution of the dust distribution, accounting for different grain growth and destruction processes, with the grain collisions being driven by brownian motion, turbulence, and ambipolar drift. It also computes the charges carried by each grain species and the ion and electron densities, as well as the magnetic resistivities.
Results. We find that the dust distribution significantly evolves during the protostellar collapse, shaping the magnetic resistivities. The peak size of the distribution, population of small grains, and, consequently, the magnetic resistivities are controlled by both coagulation and fragmentation rates. Under standard assumptions, the small grains coagulate very early as they collide by ambipolar drift, yielding magnetic resistivities that are many orders of magnitude apart from the non-evolving dust case. In particular, the ambipolar resistivity, ηAD, is very high prior to nH = 1010 cm−3. As a consequence, magnetic braking is expected to be ineffective. In this case, large size protoplanetary discs should result, which is inconsistent with recent observations. To alleviate this tension, we identified mechanisms that are capable of reducing the ambipolar resistivity during the ensuing protostellar collapse. Among them, electrostatic repulsion and grain-grain erosion feature as the most promising approaches.
Conclusions. The evolution of the magnetic resistivities during the protostellar collapse and consequently the shape of the magnetic field in the early life of the protoplanetary disc strongly depends on the possibility to repopulate the small grains or to prevent their early coagulation. Therefore, it is crucial to better constrain the collision outcomes and the dust grain’s elastic properties, especially the grain’s surface energy based on both theoretical and experimental approaches.
Deuterium fractionation of the starless core L 1498
Authors: Lin Sheng-Jun , Lai Shih-Ping , Pagani Laurent , Lefèvre Charlène , Thieme Travis J. 
Published: June 2024

Context. Molecular deuteration is commonly seen in starless cores and is expected to occur on a timescale comparable to that of the core contraction. Thus, the deuteration serves as a chemical clock, allowing us to investigate dynamical theories of core formation.
Aims. We aim to provide a 3D cloud description for the starless core L 1498 located in the nearby low-mass star-forming region Taurus and explore its possible core formation mechanism.
Methods. We carried out nonlocal thermal equilibrium radiative transfer with multi-transition observations of the high-density tracer N2H+ to derive the density and temperature profiles of the L 1498 core. By combining these observations with the spectral observations of the deuterated species, ortho-H2D+, N2D+, and DCO+, we derived the abundance profiles for the observed species and performed chemical modeling of the deuteration profiles across L 1498 to constrain the contraction timescale.
Results. We present the first ortho-H2D+ (110−111) detection toward L 1498. We find a peak molecular hydrogen density of 1.6−0.3+3.0 × 105 cm−3, a temperature of 7.5−0.5+0.7 K, and a N2H+ deuteration of 0.27−0.15+0.12 in the center.
Conclusions. We derived a lower limit of the core age for L 1498 of 0.16 Ma, which is compatible with the typical free-fall time, indicating that L 1498 likely formed rapidly.
Stable and wavelength-tunable multiwavelength laser for high-rate measurement device independent quantum key distribution
Authors: Chen Jia-Lin , He De-Yong , Wang Ze-Hao , Wang Shuang , Ding Wen-Jing , Geng Jia-Qi , Yin Zhen-Qiang , Chen Wei , Fan-Yuan Guan-Jie , Guo Guang-Can , Han Zheng-Fu 
Published: June 2024

Measurement device independent quantum key distribution (MDI QKD) has attracted growing attention for its immunity to attacks at the measurement unit, but its unique structure limits the secret key rate. Utilizing the wavelength division multiplexing (WDM) technique and reducing error rates are effective strategies for enhancing the secret key rate. Reducing error rates often requires active feedback control of wavelengths using precise external references. However, for a multiwavelength laser, employing multiple references to stabilize each wavelength output places stringent demands on these references and significantly increases system complexity. Here, we demonstrate a stable, wavelength-tunable multiwavelength laser with an output wavelength ranging from 1270 to 1610 nm. Through precise temperature control and stable drive current, we passively lock the laser wavelength, achieving remarkable wavelength stability. This significantly reduce the error rate, leading to an almost doubling of the secret key rate compared to previous experiments. Furthermore, the exceptional wavelength stability offered by our multiwavelength laser, combined with the WDM technique, has further boosted the secret key rate of MDI QKD. With a wide wavelength tuning range of 5.1 nm, our multiwavelength laser facilitates flexible operation across multiple dense wavelength division multiplexing channels. Coupled with high wavelength stability and multiple wavelength outputs simultaneously, this laser offers a promising solution for a high-rate MDI QKD system.
Tilted Perpendicular Anisotropy-Induced Spin-Orbit Ratchet Effects
Authors: Chen 陈 Bin 彬 , Long 龙 Yuantu 垣图 , Nie 聂 Yulin 宇林 , Ling 凌 Ziyu 姿瑀 , Ma 马 Tianping 天平 , Zhang 张 Ruixuan 瑞轩 , Wu 吴 Yizheng 义政 , Luo 骆 Yongming 泳铭 , Wang 王 Ningning 宁宁 
Published: June 2024

Abstract
Using micromagnetic simulations, we demonstrate the tilted perpendicular anisotropy-induced spin-orbit ratchet effect. In spin-orbit torque (SOT)-induced magnetization switching, the critical currents required to switch between the two magnetization states (upward and downward magnetization) are asymmetric. In addition, in the nanowire structure, tilted anisotropy induces formation of tilted domain walls (DWs). The tilted DWs exhibit a ratchet behavior during motion. The ratchet effect during switching and DW motions can be tuned by changing the current direction with respect to the tilting direction of anisotropy. The ratchet motion of the DWs can be used to mimic the leaky-integrate-fire function of a biological neuron, especially the asymmetric property of the “potential” and “reset” processes. Our results provide a full understanding of the influence of tilted perpendicular anisotropy on SOT-induced magnetization switching and DW motion, and are beneficial for designs of further SOT-based devices.
Comparative analysis of dark energy compact stars inf(T,T)and f(T) gravity theories via conformally flat condition
Authors: Ditta Allah , Mustafa G , Maurya S K , Sofuoğlu Değer , Mahmood Asif 
Published: June 2024

AbstractThis manuscript is the first investigation of dark energy celestial phenomena in the modified gravity theory by examining dark energy compact stars within the context of modifiedf(T,T)gravity. In order to compare the outcomes of thef(T,T)andf(T) gravity theories, the modelf(T,T)=αT(r)+βT(r)+ϕis selected. This model is then simplified tof(T) gravity by settingβ = 0. Thef(T) gravity is torsion-based gravity, while inf(T,T) gravity trace of energy-momentum tensor is coupled with torsion. Moreover, we note that we have more dense object formation inf(T,T)gravity as compared tof(T)-gravity. The spherically symmetric space-time inside the internal geometry is analyzed using a conformally flat condition, while the Schwarzschild geometry represents the outer space-time. Numerous characteristics of dark energy stars are examined, including equation of state components, energy conditions, and dark energy pressure components. Empirical evidence for the existence of dark energy in stellar configurations is presented by the results for pressure components in dark energy, which show a significant negative tendency in these stellar parameters. A complete analysis is performed by thoroughly investigating energy conditions, pressure profiles, sound speeds, gradients, adiabatic index, Tolman–Oppenheimer–Volkoff equation, mass function, compactness, and redshift function. The mass-radius relation is also discussed viaM − Rcurves. This confirms that the studied star configuration is realistic and acceptable.
Insights into molecular and bulk mechanical properties of glassy carbon through molecular dynamics simulations and mechanical tensile testing
Authors: Kunte Manali , Chanfón Lucía Carballo , Nimbalkar Surabhi , Bunnell James , Rodriguez Barajas Emanuel , Vazquez Mario Enrique , Trejo-Rodriguez David , Faucher Carter , Smith Skelly , Kassegne Sam 
Published: June 2024

Abstract
With increasing interest in the use of glassy carbon (GC) for a broad range of application areas, the need for developing a fundamental understanding of its mechanical properties has come to the forefront. Furthermore, recent theoretical and modeling works that highlight the synthesis of GC via the pyrolysis of polymer precursors has explored the possibilities of a revisit to the investigation of their mechanical properties at a fundamental level. Although there are isolated reports on the experimental determination of its elastic modulus, insights into the stress-strain behavior of a GC material under tension and compression obtained through simulations, either at the molecular level or for the bulk materials, are missing. This study fills the gap at the molecular level and investigates the mechanical properties of GC using molecular dynamics (MD) simulations, which model the atomistic-level formation and breaking of bonds using bond-order-based reactive force field formulations. The molecular model considered in this simulation has a characteristic 3D cage-like structure of five-, six-, and seven-membered carbon rings and graphitic domains of a flat graphene-like structure. The GC molecular model was subjected to loading under varying strain rates (0.4, 0.6, 1.25, and 2.5 ns−1) and temperatures (300 K–800 K) in each of the three axes: x, y, and z. The simulations show that the GC nanostructure has distinct stress-strain curves under tension and compression. In tension, MD modeling predicted a mean elastic modulus of 5.71GPa for a single GC nanostructure with some dependency on the strain rate and temperature, whereas, in compression, the elastic modulus was also found to depend on the strain rate and temperature and was predicted to have a mean value of 35 GPa. To validate the simulation results and develop experimental insights into the bulk behavior, mechanical tests were conducted on dog-bone-shaped testing coupons that were subjected to uniaxial tension and loaded until failure. The GC test coupons demonstrated a bulk modulus of 17 ±2.69 GPa in tension, which compares well with those reported in the literature. However, comparing MD simulation outcomes to those of uniaxial mechanical testing reveals that the bulk modulus of GC in tension found experimentally is higher than the modulus of single GC nanostructures predicted by MD modeling, which inherently underestimates the bulk modulus. With regard to failure modes, the MD simulations predicted failure in tension accompanied by the breaking of carbon rings within the molecular structure. In contrast, the mechanical testing demonstrated that failure modes are dominated by brittle failure planes largely due to the amorphous structure of GC.
Precise orbit determination of the LuTan satellite using GPS, BDS-2, and BDS-3 signals
Authors: Zhang Yu , Zhao Qile , Jiang Kecai , Guo Xiang , Lian Yidu , Li Min 
Published: June 2024

Abstract
The LuTan satellite is the first formation-flying mission of China enabling synthetic aperture radar interferometry in the L-band. As a key mission requirement, the absolute position of each satellite must be determined with an accuracy of 5 cm in three dimensions (3D). To fulfill this demand, each satellite carries a Global Positioning System/Beidou Navigation Satellite System (GPS/BDS) dual-constellation Global Navigation Satellite System receiver that can simultaneously track the GPS L1 and L2 signals, the BDS-2 B1I and B3I signals (BD2), and the BDS-3 B1C and B2a signals (BD3). In this study, we assess the performances of precise orbit determination with different signals and their combinations. For that purpose, we produce a total of five sets of orbit solutions, i.e., GPS-based, BD2-based, BD3-based, GPS/BD2 combined, and GPS/BD3 combined solutions. To evaluate the orbit solutions, comparisons in the orbital overlaps and with the GPS-based orbit are adopted. The orbital overlap analysis shows that the GPS-based solution has the smallest root mean square (RMS) of overlap orbit differences than other single-constellation solutions with 3.7 mm in 3D. The BD2- and BD3-based orbits are suffered from large errors and the overlap RMS differences are 24.7 and 18.9 mm, respectively. Furthermore, all of the combined orbits (both 3.1 mm for the GPS/BD2 and GPS/BD3 combined orbits) based on the variance component estimation method can obtain improvement than GPS-based solutions. For orbit comparisons, the GPS-based solution is selected to serve as the reference. The RMS values of the orbit differences are 29.9 and 15.4 mm for the BD2- and BD3-based solutions, respectively. For the GPS/BD2 and GPS/BD3 combined solutions, the values are 4.1 and 4.8 mm. In general, the results agree with those obtained in the overlap analysis. These results indicate that the BD3-based orbit is superior to the BD2-based orbit, while both of them are inferior to the GPS-based orbit. We show that inaccurate ephemerides of the BDS satellites can partly explain the degraded performance of the BDS-derived orbits. Nevertheless, the orbits still fulfill the 5 cm accuracy demand and can be readily used for subsequent precise baseline determination.
PSD estimation and modal parameter identification for random vibrations with blade tip timing measurement
Authors: Chai Pengfei , Wang Shang , Xiao Zhicheng , Meng Yiming , Tian Jie , Ouyang Hua 
Published: June 2024

Abstract
Blade tip timing (BTT) is a vibration measurement technique for blade health monitoring. Most of the existing BTT analysis methods are suitable for deterministic vibration signals but are ineffective for random vibration signals that often occur in practice. Statistical analysis of BTT data is significant for random vibration analysis and improving blade monitoring efficiency. This study proposes a compressive model for power spectral density (PSD) estimation and modal parameter identification. The efficiencies of three compressive sensing algorithms, including the least absolute shrinkage and selection operator (Lasso), nonnegative least squares (NLS), and nonnegative orthogonal matching pursuit, are compared. The effects of the duration of the signal and the frequency resolution on the quality of the estimated PSD and the identified parameters are discussed. According to the analysis, to obtain accurate damping ratios, it is recommended that the duration of the signal be greater than 3000 revolutions. A Q criterion based on the half-power bandwidth is proposed to determine the set of frequency resolutions. Numerical and field tests were conducted to verify the proposed method. The results indicate that the NLS algorithm is recommended to use. The root-mean-square errors of the identified natural frequencies and damping ratios obtained by the proposed method were 0.065 Hz and 0.023%, respectively. The proposed method was verified at different rotational speeds in a field test, demonstrating the capability of the method over a wide rotational speed range and providing more opportunities to detect blade damage.
Directly-excited laser-induced thermal grating spectroscopy and thermometry with carbon dioxide vibrational transition
Authors: Song Zihao , Zhu Ning , Wang Weitian , Sahlberg Anna-Lena , Chao Xing 
Published: June 2024

Abstract
Laser-induced thermal grating spectroscopy (LITGS) has been proved for accurate thermometry and measurement of energy transfer processes in molecules. While electronic transitions are often used for excitation in previous LITGS works, here we report laser-induced thermal gratings formed by direct excitation of CO2 with an infrared (IR) laser at wavelength near 2 μm, with which high signal-to-noise ratio LITGS signals are generated (SNR ∼ 300 at room temperature). A theoretical LITGS model assuming a ‘two-steps’ energy transfer process is used to describe the recorded signal waveform, with relative fitting residuals of less than 10%. Quantitative thermometry is performed in CO2 gas flows between 293 K and 420 K, with a relative uncertainty of 1.6% and a precision of 1.1% defined as the 1-σ standard deviation of 30 repeated measurement. Furthermore, the time constants of vibrational energy transfer at different temperatures are extracted from the temporal signal waveform with a precision better than 80 ns, and the measured results are consistent with the simulation using a detailed vibrational energy transfer model. These results demonstrate IR LITGS as a potential tool for spatially-resolved measurement of the thermophysical properties of fluids, as well as molecular vibrational energy transfer processes.
Accurate extrinsic calibration for the invisible-light 1D laser rangefinder and camera
Authors: Pu Yuchi , Ren Chaofeng , Yang Xinhui , Jin Feng , Jiao Yuhang , Li Shiyuan 
Published: June 2024

Abstract
A combined sensor, comprising a camera and a one-dimensional laser rangefinder (1D LRF), has wide application across engineering sectors, notably in aerospace. This combined sensor is pivotal for earth observation and deep space exploration. To achieve precise and stable external parameters for this combined sensor, an accurate external calibration method is proposed. Initially, a technique for localized registration of laser spots is introduced to ensure precise determination of their positions, addressing the challenge of laser invisibility in a 1D LRF. Subsequently, a data evaluation criterion known as the data synthesis criterion is presented, addressing the issue of limited constraints in traditional calibration methods. This criterion evaluates relative errors encompassing 1D LRF ranging values, camera external parameters, and laser spot positions. Finally, based on the proposed criteria, a robust extrinsic calibration method is introduced that automatically filters observation data with significant errors and utilizes the growth rate of camera spatial resolution as the termination condition. The efficacy of the proposed method is confirmed through simulation experiments and real-world data experiments.