bluuebunny/crossref_metadata_2025 huggingface dataset:
An Independent Degree-eight Mars Gravity Field Model and the Expected Results from the Tianwen-1 Mission
Authors: Liu Shanhong , Cao Jianfeng , Yan Jianguo , Huang Hao , Li Xie , Barriot Jean-Pierre
Published: May 2023

Tianwen-1 is China’s first independent interplanetary exploration mission, targeting Mars, and includes orbiting, landing, and rover phases. Similar to previous Mars missions, the Tianwen-1 orbiter was designed for polar orbits during the scientific mission period but has an exceptional eccentricity of approximately 0.59. We provide the first independent eight-degree Martian gravity field model in this paper, which was developed exclusively by a team working in China with our independent software as well, based on about two months of radiometric Doppler and range data from only the Tianwen-1 mission. This model is independent from the models created by the groups at NASA Jet Propulsion Laboratory and Goddard Space Flight Center in the United States, as well as the Centre National d’Etudes Spatiales in France. Furthermore, in order to optimize the engineering and scientific benefits, we proposed a number of potential orbits for the extended Tianwen-1 mission. In order to solve a higher-degree independent Mars gravity field model, the viability of modifying the perigee height was investigated, with the priority considerations of fuel savings and implementation hazards being controlled.
An Integrated Structure Analysis Method of Active Surface Antenna by Using the Simplified Actuator
Authors: Ban You , Chai Peiyuan , Xu Qian , Feng Shufei
Published: May 2023

The main surface of a large reflector antenna is composed of thousands of panels, which are inevitably deformed under natural load, leading to a great deterioration of electrical performance of the antenna. The active surface technique is an effective method to compensate antenna deformation error and has been widely used. The actuator is a complex component, it has not been established in the antenna structure analysis model, which limits the theoretical analysis ability of the active surface technology. To solve this problem, an integrated structure analysis method of active surface antenna by using the simplified actuator is proposed. First, according to the supporting characteristics and adjusting function of the actuator, the complex actuator is simplified a simple structure of support beams, support truss and adjustment beam. Second, the finite element model of the active surface antenna including the simplified actuator is established. Then, the relationship between the adjustment value (load) of adjustment beam and the deformation of the antenna structure is deduced, and the integrated analysis method for realizing the active adjustment of panels is established. Finally, the model and adjustment analysis method of the active surface antenna in this paper is applied to an 8 m antenna, and satisfactory structural analysis results are obtained, which shows the effectiveness and universality of the method, and provides a reference for the modeling and adjustment analysis of the active surface antenna.
The Spin Measurement of MAXI J0637-430: a Black Hole Candidate with High Disk Density
Authors: Jia Nan , Feng Ye , Song Yu-Jia , Yang Jun , Yuh Jieun , Huang Pei-Jun , Gou Li-Jun
Published: May 2023

The Galactic black hole candidate MAXI J0637-430 was first discovered by MAXI/GSC on 2019 November 2. We study the spectral properties of MAXI J0637-430 by using the archived NuSTAR data and Swift/XRT data. After fitting the eight spectra by using a disk component and a powerlaw component model with absorption, we select the spectra with relatively strong reflection components for detailed X-ray reflection spectroscopy. Using the most state-of-art reflection model, relxillCp, the spectral fitting measures a black hole spin a
* > 0.72 and the inclination angle of the accretion disk i =

46.1

−
5.3

+
4.0

degrees, at a 90% confidence level. In addition, the fitting results show an extreme supersolar iron abundance. Combined with the fitting results of reflection model reflionx_hd, we consider that this unphysical iron abundance may be caused by a very high-density accretion disk (n
e > 2.34 × 1021 cm−3) or a strong Fe Kα emission line. The soft excess is found in the soft state spectral fitting results, which may be an extra free–free heating effect caused by high density of the accretion disk. Finally, we discuss the robustness of black hole spin obtained by X-ray reflection spectroscopy. The result of relatively high spin is self-consistent with broadened Fe Kα line. Iron abundance and disk density have no effect on the spin results.
Micromagnetic stimulation (µMS) dose-response of the rat sciatic nerve
Authors: Saha Renata , Sanger Zachary , Bloom Robert P , Benally Onri J , Wu Kai , Tonini Denis , Low Walter C , Keirstead Susan A , Netoff Theoden I , Wang Jian-Ping
Published: May 2023

Objective. The objective of this study was to investigate the effects of micromagnetic stimuli strength and frequency from the Magnetic Pen (MagPen) on the rat right sciatic nerve. The nerve’s response was measured by recording muscle activity and movement of the right hind limb. Approach. The MagPen was custom-built to be stably held over the sciatic nerve. Rat leg muscle twitches were captured on video, and movements were extracted using image processing algorithms. EMG recordings were also used to measure muscle activity. Main results. The MagPen prototype, when driven by an alternating current, generates a time-varying magnetic field, which, according to Faraday’s law of electromagnetic induction, induces an electric field for neuromodulation. The orientation-dependent spatial contour maps of the induced electric field from the MagPen prototype have been numerically simulated. Furthermore, in this in vivo work on µMS, a dose-response relationship has been reported by experimentally studying how varying the amplitude (Range: 25 mV
p-p through 6 V
p-p) and frequency (range: 100 Hz through 5 kHz) of the MagPen stimuli alters hind limb movement. The primary highlight of this dose-response relationship (repeated over n rats, where n = 7) is that for a µMS stimuli of higher frequency, significantly smaller amplitudes can trigger hind limb muscle twitch. This frequency-dependent activation can be justified by Faraday’s Law, which states that the magnitude of the induced electric field is directly proportional to the frequency. Significance. This work reports that µMS can successfully activate the sciatic nerve in a dose-dependent manner. The impact of this dose-response curve addresses the controversy in this research community about whether the stimulation from these μcoils arise from a thermal effect or micromagnetic stimulation. MagPen probes do not have a direct electrochemical interface with tissue and therefore do not experience electrode degradation, biofouling, and irreversible redox reactions like traditional direct contact electrodes. Magnetic fields from the μcoils create more precise activation than electrodes because they apply more focused and localized stimulation. Finally, unique features of µMS, such as the orientation dependence, directionality, and spatial specificity, have been discussed.
Bohm sheath criterion associated with magnetized collisional warm plasma containing secondary electrons and negative ions
Authors: Jha Y P , Kumar M , Malik H K
Published: May 2023

Using Sagdeev potential approach the modified Bohm’s criterion is evaluated for the magnetized electronegative warm plasma containing secondary electrons. Dependency of Bohm velocity on secondary electrons, inclination angle of magnetic field, collisionality, electronegativity and temperature ratio (electron to positive ions) are examined. Bohm’s velocity is found to be independent on the magnitude of the magnetic field but depends on its incidence angle. As the angle increases the velocity at the edge of sheath gets reduced.
A comparison between steepest descent and non-linear conjugate gradient algorithms for binding energy minimization of organic molecules
Authors: Akshaya J , Rahul G , Rishi Karthigayan S , Rishekesan S V , Harischander A , Sachin Kumar S , Soman KP
Published: May 2023

The main intention of optimization is to bring about the “best” of any model by prioritizing the needs along with a given set of constraints. There is a wide range of optimization problems, among which, unfortunately, the problems that are formulated from nature are not convex in nature. Solving non-convex optimization problems are quite trickier than the conventional method of derivatives. One such problem is Computing the minimum value of binding free energy of various molecules. Minimization of free energy of a molecule is highly significant in the field of Molecular mechanics which is the foundation of computational biology. For any molecule, free energy refers to the amount of energy needed to separate an individual particle from a system of particles or to disseminate all particles in a system. The significance of free energy is that it can be used to compute the lowest energy conformation, which corresponds to the least Steric energy. Hence, this paper aims at computing the minimum value of binding free energy of various organic molecules in isolated conditions using the steepest descent algorithm and conjugate gradient algorithm and comparing them.
Triple band terahertz metamaterial absorber within (0.4-0.46thz) frequency range
Authors: Elakkiya A , Nath Srigitha S
Published: May 2023

An ultrathin Terahertz Triple-band ideal meta material absorber with a brand-new design that is straightforward has been presented. The suggested terahertz meta material absorber has a unit cell that is made up of two D-shaped resonators with slots and a ground metallic plane. These elements are separated from one another by a polyimide dielectric substrate that has a thickness of 500 micrometers. The absorber construction that has been presented provides three distinct absorption peaks within the narrow frequency range of (0.4-0.46 THz) without producing any interference. In order to get a deeper comprehension of the mechanism behind the absorption process, an investigation into the electric field, the magnetic field, the surface current distribution, and the independence of the polarization angle has been carried out. It is anticipated that the configuration of the terahertz absorber that has been described would find use in applications relating to the lowering of radar cross-section, detection, imaging, and sensing. One of the contributions of this study is the description of a downsized and compact triple-band terahertz meta material absorber. In order to generate the unit cell of a terahertz absorber, an identical I-typed resonator, which is represented by a rectangular patch with two very small notches, is first deposited on top of a dielectric sheet and then a metallic mirror. The terahertz regime reveals three distinct frequency spots, and the design of the very small structure allows for virtually full absorption of all of them.
Effect of Al2O3 filler in GFRP/banana fiber composite for CNC vertical milling
Authors: Surya Kumar K , Anbuchezhiyan G
Published: May 2023

This study examines the drilling characteristics on GFRP/Banana fiber composite without and with use of Al2O3 filler used in fabrication. of an epoxy-based glass fiber reinforced polymer with and without filler made of banana fiber and aluminum oxide powder. hand layup technique employed in fabricating Three kinds of polymer composites. Pre-test G power for testing was set at 80%, Alpha was set at 0.05%, and CL was set at 95%. This number of samples for each group was then determined. Three groups of nine samples each are used to experiment at CNC and MRR performance evaluated. Controlled variables were feed, drill diameter and spindle speed. The test findings were examined and contrasted using a one-way ANOVA test. The end outcome is MRR. To compare the rates of samples with and without fillers, test data were employed. Software called SPSS V16 was used to determine how significant the results were. A significant level of p0.05 was obtained from the statistical value analysis. The machinability of proposed composite is found good in terms of MRR. That MRR 9.89% fpund excess than machining of plain GFRP. In a similar vein, it was discovered that machining of alkaline-treated glass fiber/banana fibre composite found increase of 14.99% than plain GFRP laminate.
Influence of austempering temperature on carbide free bainite development, a critical review
Authors: Kumar Rajan , Tripathi Ajay , Dwivedi Ravi Kumar , Arya Ranjeet Kumar , Yadav Anil Singh , Agarwal Anupma
Published: May 2023

In this review paper, it is well established that high carbon high silicon steels on austempering result in carbide free bainite (CFB) which exhibits enhanced mechanical and tribological properties without adding any heavy alloying elements. Most of the research has been pointed out regarding the improvement of CFB steels that consists of the fine structure of bainitic ferrite laths and retained austenite (RA). In some cases, it was observed that the tensile strength of CFB steels was found similar to the commercial quenched and tempered steel alloys. Regarding other properties, it is estimated that out of the various failures that take place due to wear, 50% are caused by abrasive wear. To improve the lifetime of components, the selection of material and optimized processing techniques plays a pivotal role.
Turbulent natural convection heat transfer enhancement of nanofluids
Authors: Prakash R , Kamatchi R , Selvam R , Devanathan C
Published: May 2023

This study investigates the enhancement of heat transfer for the fluid with the addition of nano-particles in a two-dimensional rectangular cavity. Thermo-physical properties of such fluids and volume fraction of nano-particles in those fluids and its heat transfer characteristics are studied. ANSYS Fluent code is utilized for this purpose. Validation of the computational model has been carried out against the benchmark data available from the literature. A heat transfer correlation in terms of the Nusselt number (Nu) average as a function of Grashoff number and volume fraction of the nano-particles in the base fluid for the turbulent flow is developed and formulated in this study.
Modeling of process parameters on DSS 2205 through RSM, ANN, fuzzy under cryo-MQL process
Authors: Sharma Rajeev , Kumar Jha Binit , Pahuja Vipin
Published: May 2023

Duplex stainless steel (DSS) 2205 is considered difficult to cut machine materials. Therefore, an advanced cooling technique, such as a hybrid Liquid carbon dioxide (LCO2)-Minimum quantity of lubrication (MQL) approach, is proposed for drilling duplex stainless steel 2205. In this research study, parametric optimization was performed by using the Response surface method (RSM) with the box-Behnken design of the matrix. For parametric optimization, select three input parameters: drill diameter, spindle speed, and feed rate, while hole deviation and cylindricity error are output responses. The Analysis of variances (ANOVA) test showed that spindle speed is the major factor that influences both responses, e.g., hole deviation and cylindricity error, with contributions of 38.90% and 59.42%, respectively. The modeling and predictive abilities of developed Fuzzy logic system (FLS) and Artificial neural network (ANN) to the comparison of experimental results. It was also found that the predicted values from regression analysis, artificial neural networks, fuzzy logic interfaces, and the proposed method were in good agreement with actual experiment results. Also, the Artificial neural network model provides a minimum % of error of 1.36% and 2.44 %, respectively responses compared to other models.
Graphene based rectangular microstrip patch antenna for UWB applications
Authors: Asha S , Shanthy KR , Krishna Kumari S
Published: May 2023

According to the findings of the article, researchers looked at graphene-based hexagonal microstrip patch antennas. In place of a U-shaped slot and an elliptical slot, an ellipse-shaped slot was cut into the surface of the hexagonal radiators that were used in the designs that were recommended. This helped to improve the radiation performance of the radiators. A frequency known as ultra-wideband (UWB) is used in the modelling process for the anticipated structures. Through the use of comparative studies, an investigation into the effect of U-shaped and elliptical-shaped slots on the radiation performance of proposed graphene antenna designs has been carried out. The use of ellipsoidal slot-loaded structures results in considerable enhancements and advancements in directivity. The impedance bandwidths for S11 antennas with a gain of 10 dB range from 0.68 to 1.63 terahertz for U-shaped and elliptical-shaped slot loaded hexagonal printed antennas, respectively. Extensive research is presented for the various characteristics of the proposed THz antenna types. The designs that were offered provide excellent impedance matching over the full operating range. This is made possible by the high reflection and VSWR values that they possess. The cutting-edge antenna design may be used for spectrum imaging, the detection of explosives, medical diagnostics, radio transmission, and the monitoring of the weather.
Weather forecast and its visualization
Authors: Ravindhar NV , Mahananda Reddy A , Sujith Reddy D , Mohan Gaddam
Published: May 2023

We have built a weather app take the current location using latitude & longitude and sends this information to the API next it gets the temperature of popular areas along with the latitude & longitude of them, then recommends the coolest area near user and shows the temperature of the user location. To get the location of the user we have used location listener. The current location of the user is fetched through location listener and data is arranged into an array list. Async Task is a method which is used to access the data at any time required and the task is ran continuously in back ground. A Weather API is used to fetch the current temperature of the popular areas within the radius of 150 km then the data is stored into an array list. From the array lists the data is assigned by a temporary variable to get the minimum temperature and the area. The outcome of the app is in format of suggestion of area with minimum temperature and current location temperature.
A smart IOT based black-box system for automobiles
Authors: Vanitha M , Arunkumar K , Hemamalini A , Yaswanth Alam
Published: May 2023

The combination of computer technology and cars has resulted in the creation of a new level of knowledge services in vehicles. The capabilities that the car recorder has are quite similar to those of a heavier-than-aircraft recorder. It is used to study the causes of automobile accidents and to avoid the loss of life and property that occurs from the collisions. In this study, a paradigm for an associate Automobile Recording System that will be installed inside automobiles is proposed. The purpose of the system is to conduct an investigation into the occurrence of accidents by searching for the reason in an objective manner and monitoring what takes place within the cars. The method also includes enhancing safety by prohibiting tampering with the recorder’s information in order to make it more foolproof. The Arduino controllers are used in order to control the various sensors. The primary objective of this study is to design a model for the recorder system that can be installed into any vehicle, located anywhere in the world. This paradigm is often conceived using the smallest possible range of circuits. This leads to the development of safer cars, improved care for accident survivors, assistance to insurance companies for auto crash reports, and improved traffic safety on roads, all of which contribute to a lower death rate. Additionally, this helps improve traffic safety on roads, which also contributes to improved road safety.
Manufacturing of non-threaded fasteners: an analysis of non-conformities during manufacturing process and abatement
Authors: Chauhan Premanand S , Sen Mayur , Agarwal Anupma
Published: May 2023

This article projects the systematic approach for reducing the rejection during manufacturing of non-threaded fasteners i.e., Dowel Pin by Basic Quality tools. It includes the systematic study of the manufacturing process of non-threaded fastener and its inspection at different stages of manufacturing. The analysis of Dowel Pin’s manufacturing process has been taken place at industry A and modification in the process, drawing and work holding device of the Machine Tool have been done. After implementation of the modifications in the manufacturing process, the desired results have been achieved. The improvement has been visualized in the results.
Optimizing the computational effort of satellite signal acquisition based on mean recognition convolutional neural network
Authors: Duan Lei , Li Chuanjun , Zhang Qingpu
Published: May 2023

The ability to synchronize the satellite signals affects the navigation performance. Only after a procedure of acquisition, namely coarse synchronization, the data information needed to position can be extracted from the satellite signals. Conventional acquisition methods rely on extending the signal integration time to improve the correlation quality of the signal. However, extending the coherent integration time results in a large computational burden, which is unrealistic for civilian receivers. In this paper, we try to optimize the computational effort in the satellite navigation signal acquisition phase and propose an algorithm based on the mean value recognition convolutional neural network. The matrix with a high mean value is separated by the convolutional neural network, and then the Doppler shift and code phase from the matrix with a high mean value is introduced, which can effectively change the computation to 1/4338 of the original one. The trained model of the neural network can be embedded into the receiver directly, which has important engineering applications.
Adaptive density peak clustering algorithm combined with sparse search
Authors: Ma Weiyuan , Duan Baobin , Wei Ping
Published: May 2023

With the advantages of few parameters and the ability to deal with clusters of arbitrary shape, the density peak clustering algorithm has attracted wide attention since it came out. However, the algorithm has problems such as high time complexity, poor clustering effect on complex data sets, and the need to manually select cluster centers. Aiming at the above shortcomings, an improved density peak clustering algorithm is proposed. Combined with the sparse search algorithm, the calculation of the similarity between each point and its nearest neighbor is simplified, and the problem of the high time complexity of the algorithm is overcome. A new local density definition method is adopted to make the density of data points better reflect the spatial structure of data distribution and to improve the clustering accuracy of the algorithm. Finally, a strategy for automatically selecting cluster centers is proposed to improve the adaptability of the algorithm. The algorithm is used to compare with the other improved algorithm on artificial data sets and real data sets. The experimental results show that the proposed algorithm can show a better clustering effect and can quickly and accurately identify various complex clusters.
Traffic flow prediction model based on gated graph convolution with attention
Authors: Lei Yi , Liu Mingsheng , Xie Yunchi , Nie Xuefang
Published: May 2023

As a significant part, flow forecasting is crucial to road planning, traffic control, and planning. Aiming at the problem of insufficient dependence of traffic prediction methods, we proposes an Attention-based Gating mechanism Graph Convolution Network (AGGCN). Firstly, it constructures traffic flow data and adjacency matrix based on the graph data construction method. Secondly, it utilized the diffusion graph convolution method to model the traffic flow in the traffic road network. Finally, the attention mechanism to predict the traffic flow. The experiments were carried out on two highway datasets PeMS04 and PeMS08 in California, USA. Compared with the 7 commonly used algorithms in traffic flow prediction, the MAE, MAPE, and RMSE of the AGGCN model are better than other baseline experiments.
Simulation and Experiment of Cardiopulmonary Resuscitation Robot
Authors: Zou Xianghua , Li Bin , Wang Cong , Chang Jian , Li Yanbin
Published: May 2023

Aiming at the emergence of patients with outdoor cardiac arrest, to strive for more golden rescue time, a robot suitable for the rescue of patients with outdoor cardiac arrest is proposed. Combined with the medical research on the human thorax, the dynamic model of the human thorax is established, the kinematics and dynamics of the end effector mechanism are analyzed, and the robot is simulated for cardiopulmonary resuscitation in the human thorax with Adams software. The relationship between the stroke, speed, acceleration, driving torque, and time of the end effector is obtained. Second, the dynamic formula theory is simulated with Matlab software. The difference between the theoretical driving torque and the simulation driving torque is 5.2% and 2.3% respectively. Finally, the feasibility of the CPR operation of the robot is preliminarily verified through experiments.
Research on Control Theory System Based on Computer Artificial Intelligence Technology
Authors: Ke Qian
Published: May 2023

This paper designs a temperature control system. AT90S8535 is a kind of excellent performance and has the development potential of microcontrollers. In this paper, the artificial intelligence algorithm and PID adaptive algorithm are used to optimize the system control process. Fuzzy rules are used to adjust PID in the control system. Control parameters can be set automatically. This new algorithm can eliminate the phenomenon of PID saturation integral and improve the response speed while reducing overshoot. The system is stable, reliable, and easy to install. It can effectively realize remote temperature acquisition and control with low cost and low power consumption of terminal nodes. The system achieves the purpose of safe and reliable data transmission.
High resolution metrology of autoionizing states through Raman interferences
Authors: Plunkett A. , Wood J. K. , Alarcón M. A. , Biswas D. , Greene C. H. , Sandhu A.
Published: May 2023

Metrology of electron wavepackets is often conducted with the technique of photoelectron interferometry. However, the ultrashort light pulses employed in this method place a limit on the energy resolution. Here, weadvance ultrafast photoelectron interferometry access both high temporal and spectral resolution. The key to our approach lies in stimulating Raman interferences with a probe pulse and while monitoring the modification of the autoionizing electron yield in a separate delayed detection step. As a proof of the principle, we demonstrated this technique to obtain the components of an autoionizing nf′ wavepacket between the spin-orbit split ionization thresholds in argon. We extracted the amplitudes and phases from the interferogram and compared the experimental results with second-order perturbation theory calculations. This high resolution probing and metrology of electron dynamics opens the path for study of molecular wavepackets.
Two-photon absorption in La0.05Gd0.95VO4 crystal at 523 nm under irradiation with picosecond pulses
Authors: Chunaev D S , Kravtsov S B , Zverev P G
Published: May 2023

Two-photon absorption (TPA) in La0.05Gd0.95VO4 crystal under irradiation with picosecond laser pulses with the duration of 25 ps at the wavelength of 523.5 nm has been investigated. The TPA coefficient was measured to be 0.074 cm/GW. We found that the two-photon inter-band excitation led to the creation of optical centers, which were characterized by a wide absorption band in the visible spectral region. The decay of the induced absorption is characterized by two temporal stages. The first rapid stage has the decay time of about 70 μs. However, the slow stage is characterized by a decay time ranging from 270 to 520 ms depending on the initial concentration of the induced optical centers. Induced absorption should be taken into account when developing vanadate lasers with intra-cavity second harmonic converters.
Research and application of distributed energy storage and distributed photovoltaic economic optimal configuration method considering multiple constraints
Authors: Liu Caiyan , Cheng Ziyun , Yao Wenqian , Li Tianting
Published: May 2023

Energy storage is an effective measure to reduce the adverse impact of large-scale distributed photovoltaic access on the distribution network. Due to the high cost of the energy storage system, power grid planners urgently need to solve the problem of the optimal configuration of energy storage and photovoltaics. Therefore, this paper proposes a distributed energy storage planning and configuration method to promote the distributed photovoltaic consumption of the whole region. This method takes the maximum benefit of distributed photovoltaic energy distribution and storage as the objective function and takes power balance, charge-discharge power constraints, energy constraints, state of charge, and other constraints. Finally, a typical case of photovoltaic connection to an IEEE 33 node distribution network is selected to conduct a simulation analysis on the optimal configuration of different access locations for energy storage. The results show that after the energy storage system is connected, the node voltage offset of the distribution network is significantly improved, and the voltage quality is improved, which verifies the effectiveness of the capacity allocation method in this paper.
Improved climbing algorithm with variable step size in tidal energy Application of maximum power tracking control technique for power generation system
Authors: Liu Wenzhou , Yao Xiaoyan , Xiao Xu , Salvatore Francesco , Yang Jinghuan
Published: May 2023

In the context of carbon neutral carbon peak, in order to cope with climate change caused by environmental pollution and energy shortage caused by excessive use of fossil energy, the vigorous development of clean, low-carbon, and efficient renewable energy has become a major strategic direction. The development and utilization of tidal energy in China is still a certain gap with the European powerhouse, the efficiency of tidal energy generation at a low flow rate is low and the scale of development and utilization is small. The feasibility of the proposed strategy is verified by simulation analysis, and the results show that the improved variable step climbing algorithm can quickly track the maximum power point and operate stably at this point.
Frequency Control Strategy of Energy Storage and Thermal Power Unit Considering Cost and Performance
Authors: Liu Jiajie , Zhu Jianguo , Tao Hongfei , Wei Nan
Published: May 2023

Considering differentiated frequency regulation(FR) characteristics between energy storages and thermal power units, a frequency control strategy considering cost and performance is proposed to realize the complementary advantages of them. A joint objective of minimizing total cost and minimizing the penalty for failure of energy storage to track a given signal is proposed. The technical characteristics of FR resources, such as power and creep rate, are adopted as constraints. The comparison results demonstrate that the suggested approach improves the FR regional grid’s performance and reduces the regulation cost.
A Scenario Reduction Method of PV Output Based on NBSO Algorithm and STDI Index
Authors: Wang Weiyuan , Cheng Jinmin , Gao Yifan , Yu Xuan
Published: May 2023

Photovoltaic output has strong randomness and volatility. Research on the scenario reduction method of PV output is of great significance for the planning, design, and operation of power grids. This paper proposes Nonlinear Brain Storm Optimizer (NBSO) to improve the k-means algorithm, and uses the Standard Deviation Based Index (STDI) to evaluate the effectiveness of clustering. The simulation results show that the clustering method proposed in this paper can effectively reduce the PV output scenes, and the generated typical scene set can fit the output volatility and diversity of the initial scenes.
Online Probabilistic Static Security Assessment for Power Systems Considering High Renewable Penetration
Authors: Cao Bin , Wang Liqiang , Zhang Xiuqi , Hu Siyuan
Published: May 2023

With the rapid development of renewable energy, a large number of renewable energy stations are connected to the power system, which leads to a decrease in the inertia of the power system and an increase in safety risks suffered. Thus, online static security assessment (SSA) is increasingly necessary. However, because of the uncertainty of renewable energy, it is not feasible to check all possible scenarios in online SSA. To reduce the number of calculations and achieve SSA in a short time, a new online SSA method based on scenario clustering for future ultra-short-term security assessment is proposed in this paper. In the offline stage, a key scenario set is constructed by Markov Chain Monte Carlo and K-means with historical data. In the online application, the initial probability distribution of renewable energy outputs is calculated by joint distribution with the output of the previous interval and corrected by weather data. Then load flow calculation with N-1 criteria is executed, and the probability for the safe operation of the system is calculated. The effectiveness of the proposed online SSA scheme has been verified in the IEEE-300 system, where one of the generators is replaced by a renewable energy station.
Research on Virtual Synchronous Generator with Frequency Error Free Control
Authors: Zhan Weiqiang , Hu Liang , Yang Guang , Wang Fan , Yang Mingbo
Published: May 2023

A virtual synchronous generator control strategy based on the power angle characteristics of synchronous generators is designed for the independent distributed generation system. The control strategy designed has good stability, and realizes the zero difference control of the virtual synchronous generator frequency. The virtual synchronous generators can coordinate the power output in real-time, and show good stability in single-machine operation and multiple parallel operations. Finally, the effectiveness of the designed control strategy is verified by Matlab/Simulink simulation.
Fault Diagnosis of Rolling Bearings in VMD and GWO-ELM
Authors: Jiang Haisheng , Lu Hongyu , Zhou Jun , Liu Mingxiang
Published: May 2023

Strong noise, nonlinearity, and complex frequency are the remarkable symbols of vibration signals when rolling bearing failure. So a new method that improved the accuracy of rolling bearing fault diagnosis is proposed based on variational mode decomposition (VMD) and grey wolf algorithm optimized extreme learning machine (GWO-ELM). The bearing vibration signal is decomposed by VMD, and decomposed Intrinsic Mode Component (IMF) is used for fuzzy entropy calculation to construct a multi-scale complexity eigenvector. The fault pattern recognition is carried out in the extreme learning machine afterward. The parameter selection problem in VMD and fuzzy entropy algorithm is analysed through the experimental fault data of the rolling bearing, and the noise robustness of the experimental data is verified. Through fault data of rolling bearings on site, the comparison of the results shows that the GWO-ELM model can effectively identify the abnormal conditions, and has a faster training and learning speed in diagnosing the faults.
Design of Wireless Power Transfer System Based on LCC-S
Authors: Zhao Rongqiang , Xu Fei
Published: May 2023

Recently, wireless power transfer (WPT) technology has become a research hot spot due to its benefit of contactless power transfer. Firstly, for the sake of solving the problem of the small coupling coefficient of traditional orbital wireless power transfer systems, a new structure and control strategy of transceiver coil was proposed, and then the optimal parameters of system transmission efficiency were found out by comprehensive analysis of the LCC-S compensation circuit structure and equivalent circuit, and the correctness of the parameters was verified in MATLAB/Simulink simulation. Finally, an experimental prototype was built, and the experimental findings show that the wireless power transfer system based on LCC-S can realize voltage regulation control, the coupling coefficient is increased by 0.4 compared with the traditional orbital structure, and the transmission efficiency of this system is more than 80%.
A Protection Scheme for DC Distribution Line based on the Fault Current Limiting Control of DAB Converter
Authors: Qian Yang , Zhang Jinhua , Di Ya , Wang Chenqing
Published: May 2023

In the DC distribution network, the ability of the converters to withstand overcurrent is very poor. When a fault occurs in the DC line, the converter protection and line protection cannot be easily coordinated, making it difficult to ensure selective fault removal. This paper investigates protection for the DC distribution line connected with the DAB converter. First, a fault current limiting scheme for the DAB converter using phase shifting and constant current control is proposed. Then a protection scheme for the DC distribution line based on the similarity of the fault currents flowing on both sides of the line is proposed. The effectiveness of the fault current limiting control scheme and the protection scheme is verified in PSCAD/EMTDC simulation.
Short-circuit Current Engineering Calculation Method Considering Crowbar Operation Priority Degree of DFIG
Authors: Su Yinsheng , Tu Sijia , Xu Guanghu , Zhao Ligang , Yao Haicheng , Huang Guanbiao , Li Bao
Published: May 2023

When fault occurs in high wind power proportion grid, the control strategy and external characteristics of the wind power plant are affected by voltage drop of grid, so the traditional short-circuit current engineering calculation is difficult to converge. A short-circuit current engineering calculation method for high wind power proportion grid, considering grid node importance evaluation and crowbar protection of DFIG(double-fed induction generator), is proposed. This paper proposes the external equivalent model of the DFIG when fault occurs in grid, considers voltage drop degree and node importance indexes, and determines the weight of each index through Delphi method. The DFIG crowbar operation priority is evaluated to ensure the successful convergence of calculation and the maximum voltage support of wind power plants. The study case shows that proposed method is superior to the traditional method.
A Probabilistic Modeling Method for Joint Output of Multi Energy Combined Generation System
Authors: Xu Min , Zhang Zhongdan , Cui Yan , Wang Tao , Yang Zhen , Wei Zhanhong
Published: May 2023

Existing methods cannot accurately establish the joint output probabilistic model of the Wind-PV-CSP multi-energy complementary generation system. Therefore, based on the analysis of the correlation and complementarity among wind power, PV, and CSP output, a method of establishing the joint output probability model of Wind-PV-CSP multi-energy complementary system by using Copula theory and Gaussian mixture model is proposed. Considering the operational history data of wind power, PV, and CSP, the Copula function based on the correlation between PV and CSP output is adopted to establish the probabilistic model of CSP-PV combined output. Moreover, the probabilistic model for the joint output of PV-wind power generation is set up using the mixed Gaussian model based on the complementarity of wind power and PV output. Subsequently, based on the probabilistic models for the combined outputs of wind power-PV and CSP-PV, the probabilistic model for the combined output of wind power-PV-CSP mixed Gaussian model was established. Moreover, three evaluation metrics-the Nash efficiency coefficient (NSE), root mean square error (RMSE), and Euclid coefficient, are used to judge the quality of the model. The operational history data of CSP-PV-wind power in Jiuquan high proportion renewable energy base is taken as examples; the simulation results verify the validity and usability of the proposed method.
Research on Preparation and Luminescence Properties of Tm3+ -doped Glass Ceramics Containing NaLa(MoO4)2
Authors: Jia Wentao , Wang Jingjing , Ling Hongran , Yao Guanpeng , Chen Zhe , Gong Tang , Xu Guangyi , Kou Xiaoyong
Published: May 2023

In the world of light-emitting diodes, Tm3+-doped glass ceramics are a crucial fluorescent material. In this study, melt-crystallization was used to create glass ceramics that were Tm3+-doped and included crystalline NaLa(MoO4)2. X-ray diffraction (XRD), scanning electron microscopy (SEM), transmittance, and photoluminescence spectroscopy were used to examine the structure, morphology, and luminescence characteristics of glass ceramics (PL). According to the findings, keeping the precursor glass at 660 °C for two hours produced microcrystals with an average size of 280 nm. Also covered is how the concentration of Tm2O3 doping affects the luminous characteristics of glass ceramics. The strongest blue light is produced at 454 nm (1D2→3F4) when Tm2O3 concentration is 0.8 mol%. The findings demonstrate that Tm3+-doped glass ceramics containing NaLa(MoO4)2 crystalline phase have promise for use in the area of color displays.
Improving the Electrochemical Performance of Fluorinated Carbons by Solvent Co–Intercalation for Rechargeable Na–Ion Battery Cathodes
Authors: Chen Pengyu , Niu Xiaobin , Wang Liping
Published: May 2023

CF
x
deliver the ultra-high theoretical specific capacity. Nevertheless, its solvent co-intercalation for rechargeable Na–ion battery cathodes has lacked investigation. Here, we explored the co–intercalation behaviour with 1 M NaPF6 in PC or FEC for various CF
x
and found that 1 M NaPF6 in FEC is conducive to solvent co–intercalation in the extended discharge voltage window to 1.0 V. Among them, F-CF0.88 cathodes present a discharge-specific capacity for the first time of 1094 mAh g−1, which keeps a stable rechargeable specific capacity of 344 mAh g−1. This improved rechargeable behaviour is connected with the solvent co-intercalation. And the reason is that the solvation energy of fluoroethylene carbonate (FEC) is larger and easier to embed. Our study offers new ideas and a deep understanding of solvent co-intercalation of CF
x
as Na–ion rechargeable battery.
Study on Effect of Tempering Temperature on Microstructure and Properties of Super Martensitic Stainless Steel Welded Joints
Authors: Liu Yunqi
Published: May 2023

The ultra-martensitic stainless steel ZG06Cr13Ni4Mo, due to its excellent corrosion resistance, good tensile property and excellent weldability, is widely used in many occasions of hydropower, thermal power, and nuclear power, especially as the preferred material for pump impeller. This type of steel has good weldability due to its low carbon content, but the low content of reversed austenite in the weld will lead to poor plastic toughness of the welded joint. The effect of different tempering processes on the microstructure transformation and mechanical properties of welded joints of ultra-martensitic stainless steel was studied. The 20 mm thick test plate was MIG welding and then tempered at 560 °C, 600 °C, and 640 °C for 2 h. The results show that after increasing tempering temperature, the microstructure gradually decreases from the base metal to the weld and gradually transforms from lath martensite to tempered sorbite; When tempering at 600 °C, the microstructure in the weld is the finest, and the size of grain size is 0.274 μm. The highest content of reversed austenite is 9.39%; In the welded joint, compared with the untempered joint, the hardness of the welded joint area decreases after tempering, and the tensile strength first decreases and then increases. The yield strength and elongation gradually increase.
Vancomycin-gingerol encapsulated niosomal formulation against carbapenem-resistant Klebsiella pneumoniae
Authors: Karbalaeiheidar Hamideh , Ashrafi Fatemeh
Published: May 2023

Alternatives to conventional antibiotics are critical in light of the increasing prevalence of antibiotic-resistant bacteria, posing a serious threat to humanity and imposing a financial burden on the community. The current study aimed to develop a Vancomycin (Van) and Gingerol (Gin) co-encapsulated in a niosomal (Nio-Gin/Van) formulation and to assess the optimized formulation as a potent antibacterial agent against carbapenem-resistant Klebsiella pneumoniae (CRKP) strains. The prepared Nio-Gin/Van was characterized via scanning electron microscopy (SEM), transmission electron microscopy (TEM), and dynamic light scattering (DLS) and Fourier-transform infrared spectroscopy (FTIR) techniques. The F4 formulation was selected as the optimal formulation due to its low polydispersity index (PDI) (0.221 ± 0.023), small size (222.8 ± 6.35 nm), and suitable entrapment efficiency (EE%) (83.73 ± 1.12 for Gin and 66.25 ± 1.34 for Van). The Nio-Gin/Van had a sustained drug release up to 72 h and posed great stability to 60 d at 4 °C with low alterations in size, PDI and EE%, which introduced it as an appropriate candidate for medicinal utilization. The antibacterial activities of Nio-Gin/Van against CRKPs isolates were investigated using a MIC assay, which revealed MIC values of between 7.81/100–125/100 μg ml−1. Microtiter-plate assays and real-time polymerase chain reaction (PCR) were used to evaluate the antibiofilm properties of Nio-Gin/Van. A microtiter-plate assay indicated that approximately 53% of 15 CRKP isolates (n = 8) produced strong biofilms, while 26.6% (n = 4) produced moderate biofilms. Additionally, real-time PCR analysis revealed that Nio-Gin/Van significantly reduced the expression of the fimH, blaKPC, mrkD, and Ompk36 genes in all CRKP isolates examined. It was concluded that encapsulating Gin-Van in niosome enhances their antibacterial and antibiofilm activity against CRKP strains and these preparations could be considered as a novel strategy for targeted drug delivery.
A Review of Intelligent Scenes Design in Underground Pedestrian System
Authors: Teng Xiao , Shen Zhenjiang , Ge Tianqi , Lei Ruolan
Published: May 2023

Underground pedestrian system is an important part of urban public space and one of the key areas to ensure and enhance the vitality of the city centre. Various types of smart devices and sensors provide the possibility to create a safer, more comfortable, and smarter space to arouse a series of research topics such as energy saving and adjustment design of the characteristics of underground space. In order to better analyze the intelligent scene in the underground pedestrian system, The paper starts by discussing the relationship between the needs of pedestrians in underground space and relevant research and cases on intelligent underground space in recent years, and then extracts related functions and devices, to form the main intelligent scenes in underground pedestrian system. In our literature and case studies, we found that intelligent scenes in underground space are ubiquitous, generating various functions for different needs, so this paper is divided into four main types of scenes to discuss. On the whole, there has not too much research about the intelligent scenes of pedestrians in the underground pedestrian system, but smart devices still have great potential in improving the quality of underground space. Our paper aims at providing the summarize the smart devices and intelligent related scenes in underground space