bluuebunny/crossref_metadata_2025_split huggingface dataset:
Exploring EEG characteristics of multi-level mental stress based on human–machine system
Authors: Yao Qunli , Gu Heng , Wang Shaodi , Liang Guanhao , Zhao Xiaochuan , Li Xiaoli 
Published: September 2023

Abstract

Objective. The understanding of cognitive states is important for the development of human–machine systems (HMSs), and one of the fundamental but challenging issues is the understanding and assessment of the operator’s mental stress state in real task scenarios. Approach. In this paper, a virtual unmanned vehicle (UAV) driving task with multi-challenge-level was created to explore the operator’s mental stress, and the human brain activity during the task was tracked in real time via electroencephalography (EEG). A mental stress analysis dataset for the virtual UAV task was then developed and used to explore the neural activation patterns associated with mental stress activity. Finally, a multiple attention-based convolutional neural network (MACN) was constructed for automatic stress assessment using the extracted stress-sensitive neural activation features. Main Results. The statistical results of EEG power spectral density (PSD) showed that frontal theta-PSD decreased with increasing task difficulty, and central beta-PSD increased with increasing task difficulty, indicating that neural patterns showed different trends under different levels of mental stress. The performance of the proposed MACN was evaluated based on the dimensional model, and results showed that average three-class classification accuracies of 89.49%/89.88% were respectively achieved for arousal/valence. Significance. The results of this paper suggest that objective assessment of mental stress in a HMS based on a virtual UAV scenario is feasible, and the proposed method provides a promising solution for cognitive computing and applications in human–machine tasks.
Experimental Study of Heavy Oil Upgrading of In-Situ Hydrogen
Authors: Pu Wanfen , Liu Renbao , Tang Xiaodong , Li Tao 
Published: September 2023

Abstract
It was reported that hydrogen production from heavy oil reservoirs was feasible. To study the effect of in-situ hydrogen on heavy oil upgrading, a static experiment of hydrogen upgrading heavy oil under different conditions was designed with nitrogen as the control group. The composition and molar content of the produced gas was analyzed by gas chromatography (GC), the microstructure of coke was analyzed by scanning electron microscope (SEM), and the change of carbon number of oil was analyzed by gas chromatography-mass spectrometry (GC-MS). The results showed that in-situ hydrogen made heavy oil produce more light hydrocarbons. The porous coke produced by heavy oil in a hydrogen atmosphere was favorable for combustion. In addition, under the action of hydrogen, the hydrocarbon in heavy oil will be accelerated to transform from high-carbon number alkanes to low-carbon number alkanes. And the viscosity reduction effect was remarkable, the highest viscosity reduction rate reached 99.79%.
Li+ Interstitial Flow in Composite State Electrolyte for Solid-State Lithium Batteries with High-Loading Cathode
Authors: Bi Linnan , Song Yaochen , Long Xin , Wang Sizhe , Liao Jiaxuan 
Published: September 2023

Abstract
Solid-state lithium metal batteries (SSLMBs) hold high energy density and are safe and reliable. However, the polymer-based solid electrolyte possesses low ionic conductivity at ambient conditions and is incompatible with the lithium anode, which seriously hinders their practical application. Solid composite electrolyte (SCE) was prepared by fixing a fast-ion conductor of Li6.4La3Zr1.4Ta0.6O12 (LLZTO) within the P (VDF-ctfe) skeleton. The “Lewis base” effect of LLZTO can be used to construct a fast ion transport layer, realize the fast coordination/decoupling of lithium ions, form a fast ion jump, and improve the density of lithium carriers. The doped SCEs hold a high ionic conductivity of 1.2×10−3 S/cm at ambient temperature and a high migration number of 0.82. In addition, SCE-3% shows intimate compatibility with the lithium anode and LiFePO4 cathode. The assembled Li//SCE-3%/Li battery can be stably tested for 1200h at 0.1 mA/cm2, and the LiFePO4//SCE-3%//Li can charge and discharge for 70 times at 0.5 C, corresponding to 70.1% capacity retention rate, showing excellent electrochemical performance. This work gives a strategy for the design philosophy of SCE with high ion conductivity in SSLMBs.
Simulation and FPGA Implementation of Transient Power Quality Disturbance Detection
Authors: Lai Xionghui 
Published: September 2023

Abstract
With the access to new energy in the smart grids and the massive use of nonlinear and unbalanced large loads, the problem of power quality becomes more and more serious. At present, the transient power quality disturbance problem has been paid more attention to. The research on transient power quality is relatively late, and various detection methods and technologies are not mature. It is necessary to use more efficient methods to detect and identify transient power quality to improve the safety of electricity use. This paper proposes to detect transient power quality disturbance by wavelet transform. In this paper, the original signal modelling of five kinds of power quality problems such as voltage sag and voltage swell. The 9/7 wavelet lifting coefficient is optimized in this paper and is carried out on the MATLAB software platform to improve the processing speed of the algorithm and realize parallel processing. The simulation results show that the improved lifting wavelet processing can effectively detect the transient power quality disturbance.
One–pot fabrication and capacitive performances of coral-like polyaniline formed in saturated salt solution
Authors: Yan Huafeng , Qin Zongyi 
Published: September 2023

Abstract
An efficient and simple template-free approach was present to construct hierarchical coral-like polyaniline (PANI) in a saturated salt solution for scalable fabricating active material with excellent performance for supercapacitor application. The structure, morphology, and capacitance properties of coral-like PANI were investigated. The coral-like PANI with a highly crystalline structure was found to be composed of nanofibers with a diameter and length of 50–80 nm and 200–500 nm, respectively. Furthermore, the prepared PANI electrode exhibited excellent capacitive performances (465.1 F g−1 at 2 A g−1) and remained 81.0 % even at 100 A g−1, and 62.2 % retained after 2000 cycles. It showed that the coral-like PANI has great potential for development in the supercapacitor field as electrode material.
Carbon Flow Analysis Method Of Distribution Network Considering High Proportion Of New Energy
Authors: Yin Yuanke , Ye Peng , Zhang Chao , Li Zezheng , Feng Yuexin , Chen Yixian 
Published: September 2023

Abstract
This paper proposes a tracking method for the carbon flow intensity of the distribution network under a high proportion of new energy. Firstly, a power flow tracking model is proposed based on the proportional sharing principle. Then, considering network loss, a model on the ground of the carbon emission flow theory of the power system is established for analyzing carbon emissions in a distribution system with a high ratio of green power. Moreover, the availability and accuracy of the model are verified by the IEEE33 node example.
Fuel Consumption Rate Optimization Analysis of Dual-fuel Marine Diesel Engines Based on Orthogonal Design
Authors: Yang Chenxi , Cai Zheng , Li Siqin , Wang Qiwei , Fan Jinyu , Li Pinfang , Huang Jialiang 
Published: September 2023

Abstract
To investigate the influence of diesel engine operating matching parameters on the comprehensive fuel consumption rate of butanol-diesel dual-fuel engines, a high-pressure combustion chamber cycle model of a 4190ZLC-2 marine medium-speed diesel engine was established using AVL-FIRE simulation software. After establishing the optimum blending ratio of butanol, the fuel system parameters were optimized using a one-time regression orthogonal experimental design method, and a mathematical model for fuel consumption rate prediction was constructed to find the combination of parameters with the lowest fuel consumption rate as the target. The study shows that inlet pressure has the greatest influence on the fuel consumption rate, followed by EGR and inlet air temperature. The lowest fuel consumption rate was achieved by combining the following parameters: (butanol blending ratio of 20%, EGR rate 0, inlet pressure 0.233 MPa, inlet temperature 325.15 K, Injection advance angle 22.6 °CA, the diameter of oil injection hole (0.26 mm); after optimization, the fuel consumption rate was reduced by 9.96% compared to the original machine.
Simulation on Methanol Reformed High-Temperature PEM Fuel Cell System and the Experimental Verification
Authors: Zhuang Peng , Zhang Ruhang , Yu Xinhai 
Published: September 2023

Abstract
A mathematical model of the SRM-HTPEM power generation system was developed to simulate the effects of parameters such as temperature and molar water to methanol ratio on the performance of the reformer and the power stack in the system. The SRM-HTPEM power generation system was built at a mobile communication base station, and the energy efficiency of the system was 45.5% at an output power of 2.8 kW. The correctness of the simulation results was verified by experiments. It finds that increasing the reaction temperature and decreasing the weight hourly space velocity will enhance the conversion of methanol and increase the CO content in the reforming gas. Increasing the molar water to methanol ratio of the feed can improve the methanol conversion and reduce the CO content. However, if the molar water to methanol ratio is too high, the energy efficiency of the system may reduce. Appropriately increasing the operating temperature of the stack, anode hydrogen concentration and hydrogen excess ratio will increase the performance of the fuel cell.
Turbulence influence factor estimation of gasoline-air explosion in multi-branch tubes
Authors: Zhang Peili , Xiao Jun , Duan Jimao , Xiang Shuo , Shen Ting’ao , Yang Chaoshan 
Published: September 2023

Abstract
To estimate the turbulence influence of the branch tubes on the rising rate of gasoline-air mixture explosion overpressure, turbulence factor α was introduced to modify the formula of the peak rise rate of explosion overpressure. Then, the experimental data of peak explosion overpressure and overpressure rise rate under the different numbers of branches were obtained. Finally, the experimental data and laminar flame velocity were put into the overpressure rise rate correction formula, and the turbulence influence factors under different branches were calculated. The results show that increasing the number of branches will improve the turbulence degree of the explosion process. When the number of branching pipes is 1, the turbulence impact factor is about 2.0 times that in the case of no branch tube, while when the number of branch tubes is more than 1, the turbulence impact factor fluctuates about 3.5 times.
Bismuthene nanosheet anchored on planar Cu foil enabled a stable lithium metal anode
Authors: Liu Ying , Liu Wanqiang 
Published: September 2023

Abstract
Lithium metal as an anode is high-profile in rechargeable batteries, owing to its small gravimetric density, lowest redox potential, and incomparable theoretical specific capacity. Unfortunately, severe dendrite growth and fluctuant solid electrolyte interphase severely hampered its application. Herein, a hierarchical three-dimensional Bi/Cu skeleton is prepared by replacement reaction. The porous Bi/Cu can restrain the random deposition of Li through distribute the current evenly across the Bi/Cu electrodes. Meanwhile, the lithiophilicity of Bi reduces the nucleation overpotential. In contrast to the Cu skeleton, the 3D Bi/Cu skeleton significantly enhances the electrochemical performance. Furthermore, the prepared Bi/Cu anode owns highly stable coulombic efficiency, and symmetrical cells can maintain for more than 800 h (current density is 0.5 mA cm-2).
Off-grid Operation Research Energy Router Strategy on the Base of Hierarchical Control
Authors: Yang Junkun , Zhang Xiaohong 
Published: September 2023

Abstract
To coordinate off-grid control of the Energy Router, the Energy Router topology is first analyzed using isolated bidirectional full-bridge DC/DC inverters for DC ports, boost converters for PV units, and three-phase voltage-based bridge inverters for AC ports. Then the system is layered, with the lower layer developing different control strategies for different ports, the upper layer layering the DC bus voltage and dividing different operating modes in combination with the energy storage SOC, and then developing strategies for each mode. Finally, simulations are built in the MATLAB platform according to the topology to verify the possibility of off-grid operation of the energy router.
Medium and Long Term Scenario Generation of Multi-Temporal Renewable Energy Based on GAN
Authors: Hu Rong , Du Fei , Liu Zhong , Zhang Xipeng , Sun Jiawei 
Published: September 2023

Abstract
With China’s “double carbon” target, the future power system will show A significant percentage of the energy generated comes from renewable sources, specifically wind power, which has obvious randomness, volatility and intermittency, and will have a greater impact on the safety of the power system. How to effectively characterize the randomness and volatility of its power output is a major challenge for power system dispatch. The method we suggest in this paper utilizes generative adversarial networks to produce medium- and long-term scenarios for wind power generation. This approach allows for the creation of multiple sets of wind power generation data that share the same characteristics as the historical data., Our approach takes into account the spatial correlation between wind power generation at wind farms situated in various geographic locations, fully describing the randomness and spatio-temporal correlation of wind power, and providing an important reference for power system planning and scheduling.
Cooperative Primary Frequency Regulation Strategy of Wind Storage System Based on Variable Inertia Coefficient
Authors: Ding Lijie , Huang Gechao , Ren Zhihong , Lu Dingwen 
Published: September 2023

Abstract
Direct-drive permanent magnet synchronous wind turbine-generator (PMSG) is connected to the grid through the rotor side and grid side converter. The rotor speed is decoupled from the grid frequency, so PMSG output power cannot respond to the change in system frequency. However, with the gradual increase of wind power penetration, the static stability of system frequency is weakened, so the new grid-connected wind farm should have the ability of active frequency support. This paper proposes a cooperative primary frequency regulation (PFR) strategy for wind storage systems based on variable inertia coefficient. PMSG provides inertia based on the distribution of rotational kinetic energy and modifies the polarity of the inertia coefficient at the frequency recovery stage to speed up the frequency recovery. Droop control is realized by energy storage and variable power tracking control (VPPT). Energy storage and VPPT respectively suppress the frequency decrease/increase and only participate in the down/up single-side PFR, which can reduce the energy storage configuration capacity. And a safety discharge coefficient considering the state of charge (SOC) is introduced to prevent over-discharge of energy storage devices when outputting energy. Finally, the PFR capability of PMSG under the proposed control strategy is verified by simulation results.
Aerodynamic analysis of TLP offshore wind turbine under wind and waves
Authors: Hu Danmei , Zeng Li , Liu Jiang 
Published: September 2023

Abstract
Based on the real-scale NREL 5MW wind turbine as the analysis object, combined with the TLP floating platform, using the CFD software fluent and the Volume of Fluid (VOF) multiphase flow model, this paper simulates and analyzes the aerodynamic characteristics of the TLP floating offshore wind turbine under the wind and wave conditions by applying surge motion through UDF, and carries out an in-depth analysis of its power, axial thrust change, and blade pressure distribution. The power and axial thrust will fluctuate and change more violently as the amplitude and frequency of surge movement increase corresponding to waves. Low wave height, low amplitude, and low frequency are more obvious for local disturbance of power and axial thrust. After the surge motion is applied, the blade pressure at different times changes significantly. With the increase of amplitude, the pressure difference at the same time increases at the entire blade root, blade center, and blade tip, which focus mainly on the leading edge of the blade suction surface, and is most obvious at the blade root and least obvious at the blade tip. When the surge motion is not applied, with the increase of wave height, the front edge of the blade suction will obtain a greater negative pressure, and the pressure difference of each part will increase. The research results provide a technical reference and theoretical basis for the optimization design of the aerodynamic performance.
Design and Optimization of Flywheel Energy Storage System for Rail Transit
Authors: Gao Zhaopu , Cai Wei , Guo Qingbo , Yang Yongxi , Yang Lei 
Published: September 2023

Abstract
At present, the urban rail transit system has problems such as energy waste in the braking process and unstable grid voltage in the start-stop state. Aiming at the problems caused by the start-stop state of rail transit, considering the energy saving and voltage stability requirements of system energy management, a flywheel energy storage system (FESS) specially used for rail transit is designed. The energy system (FESS) can feed back the braking energy stored by the flywheel to the urban rail train power system when the rail train starts to cause the voltage and frequency of the traction microgrid to change. This paper proposes a flywheel energy management system based on a permanent magnet synchronous motor (PMSM), which can realize efficient energy management through efficient control of the flywheel side motor. The flywheel side permanent magnet synchronous motor adopts an improved flywheel speed expansion energy storage control strategy based on current feedforward control to improve the fast response capability of the flywheel, ensuring the output power of the flywheel at high speed. In addition, a specific multi-threshold voltage single FESS control strategy is suggested, which improves the energy-saving and voltage-stabilizing performance of the system.
Performance study of the supplemental combustion type compressed air energy storage system
Authors: Guo Zuogang , Xu Min , Xu Shen , Tan Yingjie , Liu Tong , Hao Xinyue , Chen Guangming 
Published: September 2023

Abstract
Compressed air energy storage technology is considered to be the most promising energy storage technology, but it has not been applied commercially on a large scale, partly because of the low system efficiency, with the existing efficiency being about 70%. To improve the round trip efficiency of the system, this paper proposes a supplementary combustion compressed air energy storage system based on adiabatic compressed air energy storage. The system adds supplementary combustion equipment to increase expansion machines’ inlet air temperature by burning fuels such as syngas, hydrogen, and natural gas to increase the power generation of the system. The thermodynamic performance analysis has been conducted through the thermodynamic model of the system, and the effects of parameters such as compressor discharge temperature, supplementary combustion, and air-fuel ratio on the system performance have been further investigated. The research results show that the efficiency of the system is improved by nearly 6% compared with the conventional adiabatic compressed air energy storage system. Meanwhile, the system’s round-trip efficiency can be further increased by appropriately raising the compressor discharge temperature and supplemental combustion quantity.
Efficiency and Feasibility Analysis of Wind Turbines in Tandem in a Vortex Tube
Authors: Chen Jinlu , Zou Libing , Su Dianpeng , Xiao Mingye , Yang Ruyan , Zheng Xiang Yuan 
Published: September 2023

Abstract
Polar scientific research is of great importance for the human. The exploitable wind energy of the polar region accounts for more than 20% in the worldwide sense. However, the harsh polar storms, extreme wind speed (up to 100 m/s), ice crystals and sand in the wind all hinder the exploitation of wind resources. Therefore, in order to protect the power generation infrastructure and to maximize the power generation window, this paper proposes an innovative concept of power generation first. This concept, placing multi wind turbines in tandem in a vortex tube, is based on the Venturi principle which allows the wind in a funnel-shaped air inlet to accelerate. Meanwhile, the large-scale vortices and associated turbulent kinetic energy in the tube are diminished through the inlet honeycomb grid, thus driving the multi-turbines in tandem to generate more power. Second, to verify the efficiency of this concept, the CFD simulation technology is employed to investigate the wake characteristics in two distinct flow fields, namely the open space and the vortex tube space. The simulation results are then compared with prototype site tests. The comparison confirms the superior performance of this vortex tube scheme accommodating multi-turbines and the use of a honeycomb at the inlet.
Optimization Method of Photovoltaic Microgrid Energy Storage System Based on Price-based DR
Authors: Li Jiayu , Dang Bin , Miao Guixi , Wang Xin , Yuan Liang , Xi Shengzhe 
Published: September 2023

Abstract
Extreme events lead to an increasing number of power outages in the distribution network. It is currently the most effective method to restore power supply after distribution network failure to connect distributed photovoltaic to the distribution network in the form of microgrids. However, the randomness of distributed PV output and load is the biggest obstacle limiting its development. Therefore, an optimization method of photovoltaic microgrid energy storage system (ESS) based on price-based demand response (DR) is proposed in this paper. Firstly, based on the influence of the uncertainty of the time of use (TOU) and load on the price-based DR, a price-based DR model is built. Then, taking the minimum difference between photovoltaic output and load demand as the optimization objective, the optimal operation model of price-based DR based on the fuzzy chance constrained program (FCCP) is established, and an optimization model of photovoltaic microgrid ESS based on FCCP is obtained. Finally, the fuzzy chance optimization problem is converted into a deterministic optimization problem through constraint equivalent treatment. The proposed method is verified by numerical simulations.
Analytical Calculation of Hybrid Excitation Transverse Flux Permanent Magnet Synchronous Linear Motor Based on Schwarz–Christoffel Mapping
Authors: Zhang He , Liu Hao , Sun Chao 
Published: September 2023

Abstract
An analytical calculation method of thrust and suspension force based on Schwarz–Christoffel (SC) mapping is presented for hybrid excitation transverse flux permanent magnet synchronous linear motor (HETFPMSLM) applied to a maglev train. The effectiveness of the analytical calculation is verified by three-dimensional finite element analysis. Firstly, the structure and principle of HETFPMSLM are analyzed, and its longitudinal two-dimensional SC mapping model is proposed. The magnetic field of HETFPMSLM is calculated by MATLAB’s SC Toolbox. Then the suspension force and thrust are calculated by the Maxwell stress tensor method, which is compared with the 3D finite element to verify the accuracy of the analytical calculation.