bluuebunny/crossref_metadata_2025 huggingface dataset:
Information-theoretic principles in incremental language production
Authors: Futrell Richard
Published: September 2023

I apply a recently emerging perspective on the complexity of action selection, the rate–distortion theory of control, to provide a computational-level model of errors and difficulties in human language production, which is grounded in information theory and control theory. Language production is cast as the sequential selection of actions to achieve a communicative goal subject to a capacity constraint on cognitive control. In a series of calculations, simulations, corpus analyses, and comparisons to experimental data, I show that the model directly predicts some of the major known qualitative and quantitative phenomena in language production, including semantic interference and predictability effects in word choice; accessibility-based (“easy-first”) production preferences in word order alternations; and the existence and distribution of disfluencies including filled pauses, corrections, and false starts. I connect the rate–distortion view to existing models of human language production, to probabilistic models of semantics and pragmatics, and to proposals for controlled language generation in the machine learning and reinforcement learning literature.
Programming hydrogel adhesion with engineered polymer network topology
Authors: Yang Zhen , Bao Guangyu , Huo Ran , Jiang Shuaibing , Yang Xingwei , Ni Xiang , Mongeau Luc , Long Rong , Li Jianyu
Published: September 2023

Hydrogel adhesion that can be easily modulated in magnitude, space, and time is desirable in many emerging applications ranging from tissue engineering and soft robotics to wearable devices. In synthetic materials, these complex adhesion behaviors are often achieved individually with mechanisms and apparatus that are difficult to integrate. Here, we report a universal strategy to embody multifaceted adhesion programmability in synthetic hydrogels. By designing the surface network topology of a hydrogel, supramolecular linkages that result in contrasting adhesion behaviors are formed on the hydrogel interface. The incorporation of different topological linkages leads to dynamically tunable adhesion with high-resolution spatial programmability without alteration of bulk mechanics and chemistry. Further, the association of linkages enables stable and tunable adhesion kinetics that can be tailored to suit different applications. We rationalize the physics of polymer chain slippage, rupture, and diffusion at play in the emergence of the programmable behaviors. With the understanding, we design and fabricate various soft devices such as smart wound patches, fluidic channels, drug-eluting devices, and reconfigurable soft robotics. Our study presents a simple and robust platform in which adhesion controllability in multiple aspects can be easily integrated into a single design of a hydrogel network.
In-context operator learning with data prompts for differential equation problems
Authors: Yang Liu , Liu Siting , Meng Tingwei , Osher Stanley J.
Published: September 2023

This paper introduces the paradigm of “in-context operator learning” and the corresponding model “In-Context Operator Networks” to simultaneously learn operators from the prompted data and apply it to new questions during the inference stage, without any weight update. Existing methods are limited to using a neural network to approximate a specific equation solution or a specific operator, requiring retraining when switching to a new problem with different equations. By training a single neural network as an operator learner, rather than a solution/operator approximator, we can not only get rid of retraining (even fine-tuning) the neural network for new problems but also leverage the commonalities shared across operators so that only a few examples in the prompt are needed when learning a new operator. Our numerical results show the capability of a single neural network as a few-shot operator learner for a diversified type of differential equation problems, including forward and inverse problems of ordinary differential equations, partial differential equations, and mean-field control problems, and also show that it can generalize its learning capability to operators beyond the training distribution.
Topographical profiles and mechanical property of corrosion product films on a pipeline steel in Desulfovibrio vulgaris-containing thin electrolyte layer characterised by atomic force microscopy
Authors: Wei Boxin , Xu Jin , Sun Cheng , Chen Shougang , Cheng Y. Frank
Published: September 2023

Internal corrosion of wet gas pipelines usually occurs in thin layers of water condensate with dissolved gases such as CO2, where a bacterial community can grow to cause microbiological corrosion. In this work, surface films generated during corrosion of an X52 pipeline steel under a CO2-containing thin electrolyte layer (TEL) in the absence and presence of Desulfovibrio vulgaris bacteria were characterised by atomic force microscopy. The film generated in the Desulfovibrio vulgaris-containing TEL, i.e. a mixture of FeS, FeCO3 and biopolymers, as compared with the film generated in the sterile TEL (i.e. FeCO3-dominant corrosion products), is topographically less compact and softer, with a reduced elastic modulus. After 7 days of immersion, the elastic modulus of the surface films generated in the sterile and D. vulgaris-containing TELs are 11.81 and 6.79 GPa, respectively.
Nina Cabezas Wallscheid: Enjoying the freedom to decide my research path
Authors: Van Emmenis Lucie
Published: September 2023

Nina Cabezas Wallscheid is a group leader at the Max Planck Institute of Immunobiology and Epigenetics in Freiburg, Germany. Taking a multidisciplinary approach, her lab investigates the mechanisms by which metabolites regulate the epigenetic and metabolic state of hematopoietic stem cell fate in young and upon aging, with the aim to identify therapeutic strategies for nutritional and hematological diseases. We spoke to Nina recently to learn more about her long-term interest in cell regulation, the joys of being a group leader, and the adventures she goes on while outside of the lab.
Ultra-broadband THz absorbers based on 3D graphene
Authors: Kumar Prabhat , Šilhavík Martin , Červenka Jiří , Kužel Petr
Published: September 2023

We use terahertz and multi-terahertz spectroscopy to investigate optical properties of three-dimensional (3D) graphene across a wide frequency range of 0.15–10 THz. We explore the electromagnetic shielding, stealth, and absorber capabilities of 3D graphene samples annealed at various temperatures up to 1300 °C. We show that the tradeoff between the transmitted, absorbed and reflected power of the materials can be controlled by the annealing temperature through a fine broadband tuning of the refractive and absorptive indices of the material. This ultralight system (with a specific mass of

∼
7

mg c

m

−
3

) is capable of acting as a stealth element (non-annealed sample,

R
<
1
%

), THz absorber (annealing at 750 °C,

A
>
85
%

) or a shielding coating (annealing at 1300 °C,

T
<
0.1
%

) within an ultrabroadband range of 0.2–7 THz. All these properties can be combined by stacking these materials on top of each other, which provides unique opportunities for THz applications.
An age- and sex-specific biokinetic model for radon
*
Authors: Samuels Caleigh , Marsh James , Leggett Rich
Published: September 2023

Abstract

Publication 137 of the International Commission on Radiological Protection (ICRP) describes a biokinetic model for radon used to derive dose coefficients for occupational intake of radon isotopes. The model depicts transfer of inhaled or ingested radon to blood, exchange of radon between blood and tissues, and gradual loss of radon from the body based on physical laws governing transfer of a non-reactive and soluble gas between materials. This paper describes an age- and sex-specific variation of that model developed for use in an upcoming ICRP series of reports on environmental intake of radionuclides by members of the public titled ‘Dose Coefficients for Intakes of Radionuclides by Members of the Public’. The proposed model modifies the model structure and transfer coefficients presented in Publication 137 to allow more realistic dosimetric treatment of bone marrow and breast and expands the model to address pre-adult ages, based on the physical principles used in the development of the model of Publication 137 together with anatomical and physiological changes occurring during human development.
Fault detection system of subway sliding plug door based on adaptive EMD method
Authors: Wang Weibo , Liu Wenxiu , Lin Chuan , Li Mingyue , Zheng Yongkang , Liu Dong
Published: September 2023

With the rapid development of urban rail transit, the safety of subway sliding plug doors has become a great concern. To improve the operational reliability of the sliding plug door, we developed a fault detection system based on the adaptive empirical mode decomposition (AEMD). Firstly, we designed a hardware acquisition device and analysis software to collect motor current signal data during the opening and closing of the sliding plug door. Secondly, to address the impact of noise on signal analysis, the AEMD denoising method is proposed. This method employs EMD to obtain intrinsic mode functions (IMFs), and select the appropriate IMF components for reconstruction based on the adaptive threshold of Hausdorff distance, resulting in improved denoising effectiveness. Thirdly, waveform segments of different faults are sliced to reduce the amount of computation and effectively improve recognition accuracy. Meanwhile, this paper utilizes feature selection methods and machine learning techniques to classify the 12 subway sliding plug door faults. It is worth noting that most of these faults have not been extensively studied in previous classification research. The experimental results show that the identification accuracy reaches 98.96% on the practical platform. Moreover, the effectiveness and robustness of our proposed method are further validated through practical tests, ablation experiments, and comparisons with other relevant literature.
Rapid production of silver nanofibers using a self-reducing solution
Authors: Zhao Xu , Onodera Chiho , Muraoka Mikio
Published: September 2023

Silver nanofibers (Ag NFs) have gained considerable attention because of their high transmittance resulting from the size effect, excellent electrical conductivity, and mechanical properties. However, synthesizing high-quality Ag NFs remains a challenge. This paper reports a novel self-reducing solution that contains platinum nanoparticles for the rapid production of Ag NFs. The method involves generating the precursor NFs and heating them in air, which reduces silver nitrate to Ag NFs within a few minutes. The as-prepared solution is characterized by its simple preparation, cost-effectiveness, and broad applicability. Additionally, the use of high-pressure airflow to directly spin the solution and a complete self-reduction system that does not depend on external conditions broadens the application prospects of the as-developed solution. Furthermore, we provide insights into the self-reduction mechanism and guidance on the preparation of self-reducing solutions.
Investigating the influence of temperature-dependent rheological properties on nanofluid behavior in heat transfer
Authors: Hassan Mohsan , Rizwan Muhammad , Bhatti M M
Published: September 2023

Nanofluids are advanced heat transfer fluids whose performance is influenced by various thermo-physical properties, including nanoparticle volume fraction, base fluid, and temperature. Rheological mathematical models have been established by using empirical data in order to characterize these features as dependent on parameters such as volume fraction, base fluid composition, and temperature. These models have been integrated into transport equations. Nanofluids composed of metallic oxides (Al2O3, SiO2) and carbon nanostructures (PEG-GnP, PEG-TGr) dispersed in deionized H2O, with nanoparticle concentrations ranging from 0.025% to 0.1%, and temperatures between 30 °C and 50 °C, were utilized to investigate flow over thin needle. The rheological models contained transport equations include the partial differential equations. The transport equations were simplified through various transformations and then solved numerically. The results in form of velocity and temperature distributions were obtained, along with boundary layer parameters, Nusselt number and coefficient of skin friction. The present study contributes to the existing knowledge by elucidating the intricate relationship between nanoparticle volume fraction, base fluid properties, and temperature in nanofluid behavior.
Nonlinear dissipative wave trains in a system of self-propelled particles
Authors: Edouma Biloa Blaise P , Tabi Conrad B , Ekobena Fouda Henri P , C Kofané Timoléon
Published: September 2023

The paper addresses the existence of modulated nonlinear periodic wave trains in a system of self-propelled particles (SPPs). The reductive perturbation method reduces the model hydrodynamics equations to a one-dimensional (1D) complex Ginzburg-Landau (CGL) equation. The modulational instability (MI) phenomenon is studied, where an expression for the instability growth rate is proposed. The latter is used to discuss regions of parameters where trains of solitonic waves are likely to be obtained. This is highly influenced by the values of the variances of Gaussian noise in self-diffusion and binary collision. Solutions for the CGL equations are also studied via the Porubov technique, using a combination of Jacobi and Weierstrass elliptic functions. Wave propagation in the self-propelled particles flock includes modulated nonlinear wave trains, nonlinear spatially localized periodic patterns, and continuous waves.
Two interacting electrons in N-dimensional quantum dot with generalized cornell potential
Authors: Dossa Finagnon A , Dagoudo Léonie , Avossevou Gabriel Y H
Published: September 2023

In this work, the interacting electrons in N-dimensional quantum dot with generalized Cornell potential in the presence of an external magnetic field are investigated using the Laplace transformation method. The energy eigenvalues and the corresponding normalized wave functions are calculated. The parameter defining the force of a constant traction on the electrons is quantified and represents well the negative of the electric force. The spectrum for some special cases of the generalized Cornell potential is obtained. One of the applications of such models is the calculation of heavy quarkonia mass spectra. We have calculated these masses and the current results are in agreement with the experimental data.
Two-dimensional realization of electromagnetically induced phase grating in a quantum dot nanostructure
Authors: Batoo K M , Al-Dolaimy F , Zaid M , Omran A A , Kareem S H , Hussain S , Abdulkadhim A H , Rasen F A , Alawadi A H , Alsaalamy A
Published: September 2023

In this paper a novel method for electromagnetically induced phase grating in a quantum dot nanostructure is proposed. The four-level quantum dot nanostructure which is designed by solving the Schrödinger and Poisson equations. By size control of quantum dot and external voltage, one can obtain appropriate energy levels which can be interacted by four-optical fields. In this case, a probe, a two-dimensional standing wave and a driving field simultaneously interact by quantum dot for creation of coherent population trapping. A terahertz (THz) signal can influence the electron population in dark and bright levels, therefore optical susceptibility and transmission spectrum of probe field in the medium can be altered. In the presence of the THz field, the medium becomes phase dependent and this makes more of probe energy transfer to the higher order of the diffraction.
Core level excitation spectra of La and Mn ions in LaMnO3
Authors: Li 李 Fujian 福建 , Cheng 程 Xinlu 新路 , Zhang 张 Hong 红
Published: September 2023

Manganese-based perovskite is popular for research on ferromagnetic materials, and its spectroscopic studies are essential for understanding its electronic structure, dielectric, electrical, and magnetic properties. In this paper, the M-edge spectra of La ions and the M-edge, L-edge, and K-edge spectra of Mn ions in LaMnO3 are calculated by considering both the free-ion multiplet calculation and the crystal field effects. We analyze spectral shapes, identify peak origins, and estimate the oxidation states of La and Mn ions in LaMnO3 theoretically. It is concluded that La ions in LaMnO3 predominantly exist in the trivalent state, while Mn ions exist primarily in the trivalent state with a minor presence of tetravalent ions. Furthermore, the calculated spectra are in better conformity with the experimental spectra when the proportion of Mn3+ is 90% and Mn4+ is 10%. This article enhances our comprehension of the oxidation states of La and Mn within the crystal and also provides a valuable guidance for spectroscopic investigations of other manganates.
Enhanced resonance frequency in Co2FeAl thin film with different thicknesses grown on flexible graphene substrate
Authors: Zhou 周 Cai 偲 , Yuan 袁 Shaokang 少康 , Zhu 朱 Dengyu 登玉 , Bai 白 Yuming 宇明 , Wang 王 Tao 韬 , Liu 刘 Fufu 福福 , Pan 潘 Lulu 禄禄 , Feng 冯 Cunfang 存芳 , Zhang 张 Bohan 博涵 , He 何 Daping 大平 , Wang 汪 Shengxiang 胜祥
Published: September 2023

The flexible materials exhibit more favorable properties than most rigid substrates in flexibility, weight saving, mechanical reliability, and excellent environmental toughness. Particularly, flexible graphene film with unique mechanical properties was extensively explored in high frequency devices. Herein, we report the characteristics of structure and magnetic properties at high frequency of Co2FeAl thin film with different thicknesses grown on flexible graphene substrate at room temperature. The exciting finding for the columnar structure of Co2FeAl thin film lays the foundation for excellent high frequency property of Co2FeAl/flexible graphene structure. In-plane magnetic anisotropy field varying with increasing thickness of Co2FeAl thin film can be obtained by measurement of ferromagnetic resonance, which can be ascribed to the enhancement of crystallinity and the increase of grain size. Meanwhile, the resonance frequency which can be achieved by the measurement of vector network analyzer with the microstrip method increases with increasing thickness of Co2FeAl thin film. Moreover, in our case with graphene film, the resonance magnetic field is quite stable though folded for twenty cycles, which demonstrates that good flexibility of graphene film and the stability of high frequency magnetic property of Co2FeAl thin film grown on flexible graphene substrate. These results are promising for the design of microwave devices and wireless communication equipment.
Numerical and experimental investigation on cold drawing process of high spiral angle tube
Authors: Liu Wei , Wang Baoyu , Fu Zhenwei , Lai Zhuowei
Published: September 2023

A novel method of cold drawing process of high spiral angle tube made of 304 stainless steel is proposed. Forming principles of high spiral angle tube are calculated. New drawing dies are designed and manufactured. Numerical simulation and corresponding experiments are carried out. Forming quality and defects of cold drawing are discussed. Various factors affecting metal flow during cold drawing process are studied in detail. Finite element model of cold drawing process is established. The variation of drawing load is presented. The distributions of equivalent stress and equivalent strain in different directions during cold drawing process are analyzed. Displacements of points in axial direction and circumference direction during cold drawing process are compared respectively. The evolutions of microstructure during cold drawing process are studied.
Comprehensive evaluation of surface parameter correlation in running-in wear process
Authors: Jiang Zhihao , He Ping , Zhang Xinguo , Zhang Gengpei , Liu Fenfen
Published: September 2023

The first wear process is running-in, which is a stage of each machine system must go through. The friction pair’s surface topography is an important feature of the running-in process. After running-in, the surface topography directly affects the performance in stable working state. The wear performance of the contact pair was focused on by mostly existing studies after a time; however, we should consider the correlation of the surface topography before and after running-in. In fact, exploration of this problem is significantly important to extend the service life of machine parts and improve the running performance. Based on the three-dimensional (3D) surface topography parameter evaluation method, in this study, experiments were designed to analyze the effect of the unworn surface topography on that after running-in, and investigated the correlation of 3D surface topography parameters. The results demonstrated that the topography characterization parameters, i.e., Sa, Sq, Sv, Sdc, Str, Sdq, and Sdr under different working conditions maintained a strong autocorrelation (the correlation coefficient of the same parameter). Moreover, the cross-correlation (the correlation coefficient between different parameters) among height parameters (Sq), hybrid parameters (Sdq, Sdr), and functional parameters (Sdc, Sk) was strong. The results of the surface roughness parameters found in this study can be used as input and output feature selection research based on working conditions and surface topography prediction after the modeling research of running-in surface topography.
Thermodynamic analysis of a linear compressor vapour compression system
Authors: Fang Xueliang , Chiong Meng-Choung , Jiang Xinyue , Chen Xinwen
Published: September 2023

Linear compressors are advantageous in terms of miniaturization, high efficiency, and continuous operation without a crank mechanism. The drop-in replacement for R134a in domestic refrigerators is R1234yf. This study aims to investigate the linear compressor thermodynamic performance in vapour compression system with R1234yf by modelling and measuring key parameters such as pressure-volume (P-V) diagram, refrigerant distribution, mass flow rate, volumetric efficiency, cooling capacity, and coefficient of performance (COP). Results show that at 40 °C condenser temperature and 2 pressure ratio, the linear compressor vapour compression system achieved a maximum 299.1 W cooling capacity, which gives 4.12 COP. The thermodynamic analysis calculations are in good agreement to the results of experimental measurements, verifying the accuracy of the model.
Ultra-precision grinding of monocrystalline silicon cylindrical mirror
Authors: Li Jie , Zhou Lian , Ma Houcai , Zhang Qinghua
Published: September 2023

As one of the important functional components in the optical diagnosis system, the processing accuracy of monocrystalline silicon cylindrical mirror directly affects the overall performance of the entire experimental device. In order to obtain high-precision monocrystalline silicon cylindrical optical elements, the coordinate transfer function models of the diamond wheel in the cylindrical surface parallel grinding process were established, and the forming process scheme was proposed based on the wheel dressing precision and element grinding precision. At the end, the experiment for a monocrystalline silicon cylindrical mirror with size of 440mm × 50mm was carried out. The PV value of form error after grinding was about 2.7μm, which proved the correctness of the transfer function and the forming process scheme of monocrystalline silicon cylindrical optical element.
Research on the capacity allocation optimization of micro-grid considering wind-PV-ES
Authors: Yang Mengmeng
Published: September 2023

To achieve the goal of “2030 carbon peak and 2060 carbon neutralization” and optimize the form of multi-energy utilization in the industrial park, it is very important to fully exploit distributed clean energy and micro-grid energy system in the park. In view of the economy of micro-grid investment, the capacity proportion of wind, solar and energy storage is the key point in the planning and design stage. A capacity allocation optimization strategy of micro-grid considering wind/solar/thermal/energy storage is proposed. The model takes the minimum total cost of the system as the objective function. As the characteristics of load in the industrial park has a poor adjust ability, the energy storage is added to the integrated energy allocation system as a flexible adjustable power supply. The energy capacity allocation of micro-grid in a cement plant park in China is analysed and calculated in this paper. The results show that after the completion of wind power, photovoltaic and thermal power, the annual power generation of the project will increase by about 105540 MWh, save about 31000 tons of standard coal per year, and reduce about 84000 tons of carbon dioxide emissions. As the cost of renewable energy will be further reduced under the sustainable development of clean energy and the trend of future technology development, establishing a clean energy micro-grid in the industrial park can bring considerable economic benefits. This study can provide a reference for the capacity allocation of the energy system in the industrial park at the planning stage.
Geometric parameters optimization on storage performance degradation of ultrasonic motor based on simulation analysis
Authors: Tan Bijiao , Wang Hao , Zhang Zhaolin , Huang Shouqing , Peng Haoyuan , Yan Qi
Published: September 2023

The performance of ultrasonic motor will drift due to material degradation and other reasons during long-term storage, which will directly affect the working performance after storage. Aiming at the optimization design of geometric parameters for performance storage degradation, this paper takes the piezoelectric constant d31 of ceramic chip and the elastic modulus of colloid as the characterization parameters of product storage degradation, and takes the stator tooth spacing and the thickness of rubber layer as the analysis objects of product geometric parameters optimization, and proposes a simulation analysis method based on finite element model. Through the analysis of the simulation results, it is found that the increase of the stator tooth spacing will lead to the increase of the change rate of the 5-wave modal frequency with the degradation of the material properties, and the decrease of the overall change rate of the amplitude. However, properly reducing the thickness of the adhesive layer can effectively reduce the influence of the degradation of the piezoelectric properties of the ceramic chip and the hardening of the gel on the frequency response characteristics of the stator of the ultrasonic motor under long-term storage.
Optimal design and verification of the 6-DOF Stewart structure used in vehicle-mounted automatic assembly
Authors: Liu Tong , Lou Huawei , Huang Haitao
Published: September 2023

The Stewart structure with six degrees of freedoms (6-DOF), which has the advantages of big bearing capacity, strong stiffness and high accuracy, has been widely used in the indoor automatic assembly of aeronautics and astronautics. In this paper, a novel design method for the Stewart structure with limited installation space is proposed to extend the workspace by parameter optimization using genetic algorithm, and the performance is further verified via co-simulation. Firstly, the target function, which describes the workspace that satisfies both kinematic and dynamic constraints, is built with four parameters: the joints circle diameters and the angles between adjacent joints of both bottom and top platforms. Subsequently, the genetic algorithm is used to optimize the target function with the four parameters whose bounds are limited by vehicle-mounted installation space and structure interference. Finally, the geometry model is built in LMS. Motion and is studied using co-simulation method with the hydraulic system in AMEsim and control system in Simulink. With the cylinders motion accuracy within ±0.5 mm, the final position of top platform is consistent with the theoretical calculations, and the position error could be controlled within ±0.7 mm.
Research status and development trend of traction robot of coiled tubing
Authors: Zhao Jianguo , Wang Binfan , Chen Bo , Xiao Xiaohua , Wang Guorong , Fang Shiji
Published: September 2023

Coiled tubing (CT) is prone to buckling and locking due to axial friction when extending in large displacement directional wells and horizontal wells. The traction robot of CT can provide axial traction, which can fundamentally address the problem of difficult downward entry of CT. The operation principle, size, traction force, traction speed and other technical indicators of the existing more cutting-edge types of traction robots are analyzed, and the critical structural features of traction robots are summarized. The application prospect of drilling bridge plug technology and drilling technology of the traction robot is put forward. The main points of the research on the traction robot are summarized to provide a concise reference for the future development direction.
Ultra-precision grinding of light-weighted SiC aspheric mirror
Authors: Zhou Lian , Ma Houcai , Zhong Bo , Wang Jian
Published: September 2023

Based on the approximate 3D model of light-weighted SiC aspheric mirror, the deformation and stress at different positions along the radius caused by the grinding force on the mirror surface was analysed. Then the influence of processing parameters on grinding force was experimentally studied, and the prediction model of grinding force was established. Finally, the grinding experiment of light-weighted SiC aspheric mirror was carried out. The PV value of the aspheric surface form error was 4.15μm, and the Ra of surface roughness was about 28nm. The experimental results verified the feasibility of ultra-precision forming of lightweight SiC mirror by controlling grinding force based on process parameters.
A graph optimization approach to range-based relative location
Authors: Li Zhitian , Zhao Nan , Xiong Xingyin , Yang Wuhao , Wang Zheng , Bie Xiaorui , Zou Xudong
Published: September 2023

With the development of multi-robot cluster system, the research of multi-node relative pose estimation is in the ascendant. However, for the environment without GNSS or fixed anchors, the problem of relative pose estimation is still challenging. In this paper, a general algorithm and system framework based on graph optimization algorithm is proposed to fuse inter- and intra-robot measurements, as well as mobility models with sliding windows for relative attitude estimation. In order to verify the feasibility and universality of the algorithm, the algorithm has used to design a relative positioning system based on UWB positioning with a “single-node multi-tags” system structure, which can simultaneously obtain reliable relative positions and directions. The design of multi-source fusion can further improve the accuracy and robustness of relative positioning. Experiment results shows that in the harsh environment without GNSS and fixed anchor points, the relative pose estimation accuracy of this system can reach centi-meter level, which may be the best potential choice for relative positioning of multi robot cluster in complex environment.
Discussion on the static-thermal test technology of aircraft
Authors: Shen Zhiqiang , Xin Qi , Yan Tingfei , Liu Chuang , Lu Dongdong , Zhang Jun
Published: September 2023

During the high-speed flight of the aircraft, the cabin body will bear aerodynamic loads, engine thrust loads, structural and equipment component mass inertial loads. At the same time, aerodynamic thermal loads will be generated due to high speed flight. With the development of hypersonic aircraft technology, the demand for multi-field coupling test is more and more common. Therefore, it is necessary to carry out the technical verification of the mechanics and thermal composite test on the ground to obtain the structural characteristics. In this paper, a certain type of aircraft cabin as the research object, carried out the research on the combined mechanical and thermal test technology. The results of this paper show that the displacement response of the cabin under the combined action of force and thermal load is consistent with the change trend of the force loading curve, and the force load has obvious influence on the displacement response of the cabin. The strain response is consistent with the trend of temperature curve, and thermal load has obvious influence on cabin deformation. Through this study, we can obtain the static-thermal test technology method, and provide the technical basis for the development of similar test technology.
Computational fluid dynamic study on design and modification of underwater remotely operated vehicle
Authors: Mayo Sohaib Arshad , Shi Xindong , Hu Qiao
Published: September 2023

Remotely Operated Vehicle (ROV) has been widely used in numerous underwater exploration applications such as exploration of complex deep sea environment, pipeline detection, installation, maintenance, and repair. Thus, it is worthy to design, optimize, and performance evaluation of ROV systems for underwater exploration purposes. Computational Fluid Dynamic (CFD) is a computational approach that is very helpful and widely used to examine the flow characteristics of ROV systems. In this research work, CFD analyses of ROV bodies with different thruster blades were carried out in order to generate thrust forces by the thruster blades. For this purpose, ANSYS FLUENT was used to examine the flow characteristics over the ROV body. The analyses were performed at different flow velocities, such as 1 m/s, 1.5 m/s, 2 m/s, 2.5 m/s, 3 m/s and 3.5 m/s. The outcomes were in the form of thrust force, drag force, pressure distribution, and velocity distribution. The result shows that four-blade thruster generates maximum thrust force as compare to other ROV thruster models. The main reason behind this higher thrust force is due to the larger motion of the fluid. Similarly, drag force was also investigated and observed that the drag force is greater for thruster model 3, having four blades due to the large frontal area of the ROV body and thruster blades. The results obtained in this study are very helpful for engineers and researchers to design and optimize ROV models using numerical methods.
Enhancing sensitivity in mode-localized tilt sensors based on asymmetrically coupled resonators
Authors: Wang Zheng , Xiong Xingyin , Wang Kunfeng , Yang Wuhao , Bie Xiaorui , Li Zhitian , Zou Xudong
Published: September 2023

Mode-localized tilt sensors with amplitude ratio (AR) outputs have been proven to have a significant improvement in sensitivity over conventional frequency outputs, and the coupling stiffness between the coupled resonators is the key to sensitivity. The resonators in tilt sensors are designed identically to form coupling and have an equivalent response to the external perturbation. This paper proposes a new method to improve the sensitivity without weakening the coupling stiffness between resonators by exploiting the asymmetry of coupled resonators. Using the amplitude ratio of the asymmetrically resonators with a smaller effective mass to the resonator with a larger effective mass as the output, the sensitivity of the mode-localized tilt sensor will be increased approximately by a factor of the ratio of the effective masses of the two resonators compared to symmetrically coupled resonators. Sensitivity can be increased to twice the original using asymmetrically coupled resonators, which has been verified both in theoretical analysis and finite element method (FEM) simulation.
Three-phase Transformer optimization design based on NSGA2 algorithm
Authors: Li Zixing , Zhang Liangxian , Chen Xinfu , Xiao Wei , Li Meng , Shi Baidi
Published: September 2023

To solve the problems of lack of diversity and low quality of solution set in the solving process of traditional transformer optimization algorithm, a multi-objective optimization algorithm based on NSGA-II is proposed. Firstly, a multi-objective optimization model of power transformer winding was established with manufacturing cost, additional coil loss and transformer short-circuit impedance as optimization objectives. Secondly, NSGA-II algorithm was used to optimize the model design. The optimization results showed that, compared with traditional MOPSO, MODE and MOEA. NSGA-II algorithm had better fitness values for each target. Finally, the reliability of the scheme is proved in a 110 kV/63000 kVA prototype, which has better economy compared with the traditional scheme.
Theory and simulation analysis of parallel operation after main transformer replacement
Authors: Wang Ting , Chen Kun , Hu Xinyang , Zhang Longen , Ye Pangqi
Published: September 2023

As one of the most important main equipment in the power system, the safe and stable operation of transformer plays a vital role in ensuring the reliability of power supply. Because the three-phase parameters of the main transformer are not the same, the parameters of each phase and the three-phase load of the power grid are also different, resulting in a certain degree of asymmetry between the three-phase current and voltage of the transformer during normal operation. There will be negative sequence and zero sequence current components. The degree of asymmetry is generally small for the high-voltage power grid, but it has a large impact on the low-voltage side of the main transformer. In this paper, the parameters of two main transformers in a substation are quite different, but when they need to run in parallel, whether they can run in parallel, what are the conditions of parallel operation, these problems have been studied in theory and simulation. The results show that the two main transformers can be operated in parallel under suitable conditions. The actual operation result of a substation’s main transformer is normal, which further verifies the correctness of theoretical calculation and simulation.
PDE modelling and switch strategy controller design for a flexible detection system with output constraint and actuator failure
Authors: Li Fangyong , Cao Fangfei , Huang Shouqing , Wang Hao , Li Wenmiao
Published: September 2023

A novel approach for modelling a mine detection robot system is presented in this paper using partial differential equations and Hamilton’s principle. The system comprises a rigid arm, a detecting sensor module, and a flexible string. The paper addresses the challenges of boundary deflection constraint and actuator fault. To overcome these challenges, a unique controller is developed using Barrier Lyapunov function and switching strategy. This controller enables the robot system to achieve the desired position and eliminate the vibration of flexible string. The superiority of the designed control law is demonstrated through simulation results. Furthermore, the asymptotic stability of the closed-loop flexible system is established by the use of extending LaSalle’s Invariance principle to an infinite dimensional system. This principle ensures that the system will eventually reach a stable state over time.
An infrared stealth spherical target simulation device and its surface temperature control algorithm
Authors: Gao Xiaohui , Feng Zhipeng , Tong Saisai , Liu Yongguang
Published: September 2023

This paper presents a simulation device for infrared stealth spherical target and a feedforward temperature compensation algorithm for its surface temperature. A three-dimensional model and a mathematical model based on heat transfer equation are established. Experimental data from three different spherical targets is used to calculate feedforward compensation and obtain a detailed control law. Experiments verify the reliability of the mathematical model and the accuracy of the temperature control algorithm. The algorithm can control the surface temperature of the spherical target within ±2 °C and has good system dynamic characteristics.
Sequence optimization for MRI acoustic noise reduction
Authors: Wang Yulin , Xu Pengfei , Zeng Jie , Zhang Jichang , Zhu Yuliang , Che Shao , Yao Chendie , Ge Yuwei , Wang Chengbo
Published: September 2023

The large acoustic noise of 80-110 dB during magnetic resonance imaging (MRI) scanning harms patients’ comfort and health. The noise can be reduced by hardware modification or active noise control, but these methods are expensive, difficult, or not very effective. In this study, a sequence optimization method is used to mitigate the acoustic noise problem while maintaining image quality. The 4th order polynomial function is applied to design the new quiet pulse sequences, decreasing the gradient slew rate and higher time derivatives of the original trapezoidal lobes. A sound pressure level (SPL) estimation method is proposed to predict the acoustic noise loudness from the gradient and is used for genetic algorithm sequence optimization. The original and quiet gradient recalled echo (GRE) sequences are applied on a 1.5 T MRI scanner. The average SPL is reduced by 18.6 dBA, and the images show small differences and have similar SNR values. This method is also applied for the scouting and shimming GRE sequences in common clinical applications with significant noise reduction.
Line loss calculation model of low-voltage distribution network under harmonic and three-phase unbalance disturbances and its experimental validation
Authors: Li Xinpeng , Wang Guo , Li Yongshun
Published: September 2023

With the grid integration of distributed power sources and traction loads, the power quality problem of the power system has become more and more serious, aggravating the distribution network line losses, so it is important to study the calculation model of distribution network line loss under power quality disturbance in order to find loss reduction measures. This paper first theoretically derives the calculation model of line loss of low-voltage distribution network under separate disturbance of 2 common power quality problems, namely, harmonics and three-phase unbalance. Then, using the composite power quality disturbance decoupling method, the calculation model of line loss of low-voltage distribution network under the disturbance of harmonics and three-phase unbalance is derived, which improves the accuracy of line loss calculations. Finally, experiments are conducted for each part by Matlab/Simulink simulation tool to verify the correctness of the theoretical derivation.
Current stress optimization control of isolated AC-DC matrix converter
Authors: Deng Wenlang , Wang Chun , Geng Zhenjia
Published: September 2023

The Isolated AC/DC matrix converter realizes bi-directional energy transmission through phase shift control. The existing control schemes do not coordinate the modulation coefficient and phase shift ratio well, which will cause large current stress to the converter, resulting in low efficiency. To solve this problem, this paper analyses the working mechanism of IAMC under dual phase shift control. It constructs a mathematical model under dual phase shift control to calculate the current stress. An optimal control method for the current stress of isolated AC/DC matrix converter is proposed. The current stress is suppressed by coordinating modulation coefficient and internal and external phase shift ratio. Finally, a simulation platform is built to verify the proposed method.
Remaining useful life prediction of lithium-ion batteries based on the Support Vector Regression Optimized and Enhanced Whale Optimization Algorithm
Authors: Wu Wei , Chen Zhen , Li Linman , Pan Ershun
Published: September 2023

Accurate and reliable predictions of the remaining useful life (RUL) of lithium-ion batteries are crucial for ensuring the proper functioning and longevity of lithium-ion battery systems. Predicting the RUL in its early stages can be challenging and difficult for conventional RUL prediction techniques. To tackle this challenge, this paper proposes a novel approach that integrates five carefully chosen health features with a Support Vector Regression Optimized model and Enhanced Whale Optimization Algorithm (EWOA-SVR) to predict the future capacity trend and subsequently estimate the RUL using XGBoost method according to the predicted capacity. The proposed approach aims to achieve early and accurate capacity estimation and RUL prediction for lithium-ion batteries. To begin, this method extracts some health features during the relaxation process and during the constant-current and constant-voltage charge (CC-CV) process. To demonstrate the strength of the correlation between the health features and capacity, both Pearson and Spearman rank correlation analysis are employed in this study. Then based on the measurable health features and faded capacity data, Ant Lion Optimization (ALO), Whale Optimization Algorithm (WOA) and EWOA are used to select suitable penalty factor and kernel parameter in the SVR algorithm to improve the performance of SVR. With the well-trained model, the future capacity can be predicted with an accuracy of MAPE within 1%, and the RUL prediction error is lower than 11 cycles. The results suggest that the proposed model can achieve a precise and dependable early estimation of the future capacity and RUL prediction.
Analysis and preventive measures of lightning protection on UHVDC transmission lines
Authors: Zhao Xia
Published: September 2023

The causes of flashover on UHVDC transmission lines due to lightning strikes are analyzed. Then, after the introduction of the characteristics of flashover caused by lightning strikes, the types of lightning strikes and discrimination method, the calculation method of lightning performance, and the methods of identification of faults, the preventive measures are proposed.
Operation control technology of source network load storage area based on flexible application of energy storage
Authors: Li Zheng , Yao Zhongyuan , Shen Xuhui , Tang Haiyan , Ba Lei , Zhang Yu
Published: September 2023

This paper studies the operation control technology of source-network-load-storage area. Firstly, the flexible application mode of energy storage in the source-network-load-storage area is analyzed. Secondly, the definitions of absolute mileage and relative mileage are proposed, and the power coordination control model of energy storage units based on mileage balance is established to achieve the purpose of efficient utilization of energy storage resources. Finally, the operation control strategy of the source network load storage area is proposed, which verifies the effectiveness and practicability of the power coordination control model of the energy storage unit and the operation control strategy of the source network load storage area.
Technical research on test method of the socket and switch of temperature monitoring alarm function
Authors: Li Rui , Wang Yongyu
Published: September 2023

The emergence of sockets and switches with fire protection monitoring and alarm functions had realized the forward detection of the fire risk monitoring gateway, which had played an important role in preventing the occurrence of electrical fires. In 2014, the national standard GB31252 “Fire Monitoring and Alarm Sockets and Switches” was promulgated and implemented, which detailed the product functions, performance and test methods of fire protection monitoring and alarm sockets and switches. This article is based on the difficulty of accurately controlling the heating process when measuring the temperature alarm value of the socket and switch. A new type of simulated temperature alarm test method was designed, and a detection device for the temperature test of the fire monitoring alarm socket and switch was developed. And the testing device was tested and verified. The test results show that the testing device designed in this paper can meet the technical requirements of the temperature part test in GB31252-2014.