bluuebunny/crossref_metadata_2025 huggingface dataset:
An Improved RGB-D SLAM Method Based on Manhattan World and Point-Line-Plane Features
Authors: Yang Dehua , Pei Hailong , Weng Zhuorong
Published: April 2023

At present, most feature-based SLAM methods are based on feature points. But in indoor environments where texture is scarce and light varies greatly, these methods will reduce the accuracy of pose estimation or even lead to pose tracking failure. To tackle the above problem, we propose an improved RGB-D SLAM method which employs point-line-plane feature extraction and matching as well as Manhattan Frames-based rotation estimation. Finally, the proposed method is proven to have good reliability and robustness in open datasets and real indoor scenes.
Design of Function of Anti-islanding in Novel Power Distribution System with Distributed New Energy Access
Authors: Su Guang , Shi Jinyuan , He Shengli , Han Tao , Su Biaolong , Du Hongwei
Published: April 2023

With the proposal of “Double-Carbon” goal and the acceleration of energy transformation, a large number of distributed new energy sources such as photovoltaics and wind power, are connected to the power distribution system, the power distribution system has developed into a novel distribution system with the optimization and coordination of energy as its core, thus put forward higher requirements for the safety protection of distribution network. However, when the line of distribution network is repaired or faulty, the power distribution system is very easy to cause islanding effect. Measures of anti-islanding are still implemented based on the grid-connected inverter on the user’s side, and there may be dead zones for anti-islanding protection or other abnormal situations. From the perspective of a novel power distribution system, this paper proposes the method of anti-islanding in novel distribution system with distributed new energy access. The identification of islanding criterion signal, the determination of islanding operation’s area, the generation and execution of islanding processing strategy, the evaluation of islanding processing result and the display of anti-islanding function are elaborated in detail. By analyzing the scenarios of actual application of the anti-islanding processing method, the proposed method can accurately sense the state of islanding of the distribution network and quickly isolate the operating area of islanding through remote control, and the novel power distribution system with distributed new energy access can be prevented from running in islanding, which greatly improves the efficiency of anti-islanding processing for dispatchers, so as to ensure the safe, stable and reliable operation of the distribution network.
Dispatching strategy of base station backup power supply considering communication flow variation
Authors: Ouyang Zheyu , Zhang Yanchi
Published: April 2023

With the mass construction of 5G base stations, the backup batteries of base stations remain idle for most of the time. It is necessary to explore these massive 5G base station energy storage response power transmission network scheduling. In this article, the schedulable capacity of the battery at each time is determined according to the dynamic communication flow, and the scheduling strategy of the standby power considering the dynamic change of communication flow is proposed. In addition, the model of a base station standby battery responding grid scheduling is established. The simulation results show that the standby battery scheduling strategy can perform better than the constant battery capacity.
Improvement of Dynamic Window Approach in Dynamic Obstacle Environment
Authors: Si Mingpeng , Zhou Xiangyu , Zhang Yi
Published: April 2023

The dynamic window approach (DWA) controls the movement of the robot by searching the speed space and is widely used in the path planning of mobile robots. However, in the dynamic obstacle environment, when searching for the optimal speed, it is easy to fall into the local optimal solution, which leads to the failure of path planning. In this paper, we improve DWA. According to the speed of the obstacle, the safe distance of the obstacle is dynamically changed to improve the obstacle distance evaluation item of the DWA. A new evaluation item is introduced into the speed evaluation function to optimize the search rules of the DWA in the speed space. The experimental results show that in the dynamic obstacle environment, this method can ensure the robot reaches the target point smoothly and shorten the time spent in the whole process by improving the speed evaluation function.
Improved Single-phase PLL Based on All-Pass Filter
Authors: Cao Na , Feng Wenjie
Published: April 2023

The detection accuracy of a conventional phase-locked loop for a single phase is affected by the interference of the DC component and harmonic component when the grid has a lot of problems such as harmonic interference and DC offset, and It will be unable to accurately track the grid voltage frequency and phase. The traditional APF-PLL is improved to address this problem. An improved phase-locking algorithm is proposed, combining a CSOGI and a FLL with the conventional single-phase phase-locked loop. The method incorporates CSOGI into the APF-PLL pre-stage to reduce interference from DC and harmonic components, while FLL achieves the frequency tracking of the input signal and improves the adaptivity and dynamic response speed of the phase-locked loop. Through simulation verification, the proposed new phase-locked loop can improve the frequency tracking capability, dynamic performance, and precision of the locking phase of the PLL.
Design of Octagon Monopole Dual Frequency Indoor Positioning Beacon Antenna
Authors: Ren Qiming , Zheng Meijie , Wen Shuyao , Lin Bin , Wang Qiyu , Huang Qianyi , Wang Xingye
Published: April 2023

Aiming at the antenna performance requirements of Bluetooth and UWB indoor positioning system, an octagon monopole dual-frequency indoor positioning beacon antenna is made. The antenna can operate in both UWB and Bluetooth communication bands. The antenna performance is improved by grooving the antenna and adding metal strips. The use of curved and gradual structure feeders also makes the antenna get better bandwidth performance.
Simulation and Experimental Study on Aerospace Push-button Latch of Planar Four-bar Linkage
Authors: Guo Haoran , Zhang Zonghua , Zhang Zhiqiang , Yang Wenfang , Tan Xue , Wu Zilong
Published: April 2023

This paper analyzes the relevant research on push-button quick-release latch, and presents the dynamic model of a typical push-button latch based on a planar four-bar linkage mechanism. ADAMS software was used to simulate the opening and closing performance of the typical push-button latch. The influence of push angle, push position, push speed and push acceleration on the actual opening force measurement of the product was analyzed, as well as the preload test method of the push-button latch, and the sensor method was recommended to measure the preload force, and tested by experiments. Moreover, this paper analyzes the durability test method of push-button latch, uses the sensor to detect the change of opening and closing force in the process of durability test and studies the durability test of typical products.
Design of Data Acquisition Terminal Based on the FAT32 File System
Authors: Fang Xiaojun , Lu Baochun
Published: April 2023

To meet the requirement of data acquisition for some processing equipment on the wooden door production line, this paper proposes a design scheme for a data acquisition terminal based on the FAT32 file system. The terminal uses microprocessor STM32MP157 as the core, SD card as the storage medium, and transplants FAT32 file system to manage data. Based on the analysis of the principle of the FAT32 file system, this paper improved the application and recycling of clusters to slow down the frequent wear of FAT and FSinfo sectors, and improved the data storage speed. The test results show that the system is stable and reliable, and can be used in large-capacity data storage.
Multi-Sensor Fusion SLAM Method for Underground Power Pipe Gallery
Authors: Que Jianfei , Zheng Enhui , Zou Zehai
Published: April 2023

The satellite signal in the underground power pipe gallery is missing and the light is dim, so simultaneous localization and mapping (SLAM) is facing many challenges. Aiming at this special scene, a new SLAM method based on multi-sensor fusion is proposed by using a new type of area array laser radar and a monocular camera to build a 3D scanner. The geometric structure of the global map is obtained by fusing the pre-integrated IMU data and the lidar data. The texture and color information of the global map are supplemented by visual information rendering. A data connection bridge is built between the equipment and the local server in the form of remote networking to achieve data synchronization. The experimental results of an underground power pipe gallery in Zhejiang Province show that the method significantly improves the accuracy of 3D reconstruction in complex environments, and provides a useful reference for the development of localization and mapping of underground inspection robots.
Compressed Sensing of Traction Motor Bearing Vibration Signals based on Discrete Fourier Transform and Generalized Orthogonal Matching Pursuit Algorithm
Authors: Liu Shuli , Liu Yi , Shen Longjiang , Li Lin , Shen Yiping
Published: April 2023

For the bogie traction motor bearings of rail vehicles under road transportation conditions, its vibration signal full-time domain data acquisition data volume, storage pressure, subsequent data analysis difficulties, and other problems. This study proposes a data compression acquisition and data reconstruction method for bearing vibration signals based on compressed sensing (CS), which can achieve compressed sampling, transmission, and storage of the original signal with fewer observations, and restore the original signal by combining reconstruction algorithms to achieve low error reconstruction. We study the effects of different sparse transform methods on signal sparsity, as well as the signal sparse performance based on different sparse transforms and the signal reconstruction effect of different reconstruction algorithms, and propose a sparse representation method based on the discrete Fourier transform (DFT) and the generalized orthogonal matching pursuit (gOMP) algorithm for CS. Through simulation and experimental comparison, it is concluded that the method can restore and reconstruct the original high-dimensional signal with small reconstruction error, and solve the problems of massive data, inconvenient transmission, and difficult data analysis in engineering.
Application of New Sliding Mode Observer in Sensorless Control of Permanent Magnet Synchronous Motor
Authors: Zhang Yan , Lu Huacai , Xu Di
Published: April 2023

In view of the position sensorless control system of permanent magnet synchronous motor (PMSM) under medium and high-speed conditions, the use of traditional sliding mode observers is prone to problems such as speed and high-frequency jitter and three-phase current distortion. In this paper, a saturation function consisting of an arctangent function is used instead of a discontinuous switch symbol function at the zero point to improve the speed stability and improve the three-phase current distortion problem. Simulations in MATLAB/Simulink compare the speed and three-phase current which is sliding mode observer between the traditional and the improved, the later can effectively suppress the speed jitter and three-phase current distortion.
Research on the Integration of Wireless Sensor Networks Based on IoT Technology
Authors: Qiu Wenying , He Sijia , Gu Weixi
Published: April 2023

Wireless Sensor Network (WSN) is a wireless network formed by a group of sensors with wireless transceiver capabilities, connected in a multi-hop autonomous manner. It has several advantages: low traffic, greater stability, longer wireless communication, and higher coverage areas at a lower cost. The incorporation of new NB-IoT technologies in wireless sensor networks, combining the advantages of both and the establishment of NB-IoT-based wireless sensor networks, has a very promising application in defense and military, medical, intelligent transportation, and commercial applications. This study first investigates both WSN and NB-IoT technologies separately and then combines them to investigate the networking structure of NB-IoT and WSN as well as the related technologies based on the fusion. Then the coverage method of the traditional network node redeployment of wireless sensors is described, and many problems such as poor node connectivity and low coverage are caused by the traditional method due to the lack of local search of subgroup nodes. The initialization of the nodes is carried out. The global information exchange is combined with the subgroup to determine the detectable area of the wireless sensor, and the calculus method is used for the irregular area to obtain the optimal network node so that the nodes of the wireless sensor network can be redeployed.
Application of stochastic ranking based evolutionary strategy in environmental management of microgrids
Authors: Chen Tuo , Xianyu Jianchuan
Published: April 2023

The microgrid environmental governance problem is a single objective function, and the biogeography algorithm traditionally used for the calculation has significant shortcomings. The algorithm has a limited search range at the beginning of the iteration and tends to fall into a local optimum at the end. In addition, it is slow to converge and poor in finding the best solution when solving microgrid scheduling optimization problems. In this paper, we adopt a typical microgrid environmental management framework model and use a stochastic ranking evolutionary strategy algorithm with high performance. The objective function is to minimize the ecological management cost and optimize the rational dispatch of electricity to gas and energy storage devices. The case study proves that the stochastic ranking evolutionary strategy algorithm is more efficient and converges faster. This algorithm can effectively solve the energy dispatching optimization problem in microgrids.
Event-based Non-intrusive load real-time monitoring experimental platform
Authors: Cao Na , Li Han , Yu Qun
Published: April 2023

To meet the transformation requirements of the new power system and promote the construction of a cyber-physical system. A non-intrusive load detection experimental platform is designed by using a USB data acquisition card and Matlab software. The platform is designed from several aspects such as hardware circuit, data acquisition, event detection algorithm, and load identification. A comprehensive evaluation method combining accuracy and real-time is proposed. The experimental platform has solidified typical load detection algorithms and customized algorithm expansion functions, allowing researchers to conduct innovative experiments as needed. The platform allows for the organic integration of theoretical and experimental, which not only meets the basic experimental needs but also provides an ideal platform for opening innovative and comprehensive experiments.
Research on Fuzzy PID Control of Concrete Press Based on Frequency Conversion Speed Regulation System
Authors: Li Shuiping , Cheng Zhe
Published: April 2023

In the static compression elastic modulus test of concrete, controlling the value of the loading force is the key to the success of the test. The test requires that the set force value be reached quickly, and the fluctuation should be stable within the test standard range, even in the presence of external interference. There is no oscillation in the transient process, and the best adjustment process is achieved. This article uses a variable frequency speed regulation system to control the value of the loading force, but the hydraulic system is susceptible to fluctuations due to the influence of oil pressure and temperature. Conventional PID control cannot meet its performance requirements. As a result, this article proposes a fuzzy PID for the press’s variable frequency speed regulation system. It uses MATLAB/Simulink and the controller to simulate the system. Simulation experiments show that fuzzy PID control has a better control effect than conventional PID control.
Controller design of robot nonlinear system based on the improved fuzzy sliding mode control
Authors: Lv Yin , Jin Hui , Di Yanbiao
Published: April 2023

In this paper, the input-output finite time stability of fuzzy sliding mode control in nonlinear robot systems is discussed. Specifically, the system considers more realistic factors, such as uncertainty, nonlinearity, interference, and state delay. An improved fuzzy sliding mode control (FSMC) scheme is developed, which is considered in most results of FSMC schemes. Based on the input-output finite-time stability characteristics and the proposed control scheme, the objective of this work is to reduce the effects of uncertainty, nonlinearity, disturbance, and state delay. Finally, the effectiveness and superiority of the proposed method are verified by simulation and comparison with other reference methods.
A Σ-Δ Modulator Based on an Inverter-based Integrator with Dynamic Current Switch
Authors: Zhang Chunhua , Jian Mingchao , Yuan Meng , Guo Chunbing
Published: April 2023

This paper presents a low-power high-resolution 3rd-order 1-bit Σ-Δ modulator based on an inverter-based integrator with a dynamic current switch. To reduce the power consumption of the modulator circuit, a dynamic current switch branch is added to form a low-power inverter-based integrator. A 3rd-order 1-bit Σ-Δ modulator is designed in a TSMC 65 nm CMOS technology to verify the effectiveness of the proposed integrator circuit. The prototype Σ-Δ modulator achieves 102.4 dB SNDR, 16.71 Bit ENOB in a 2 KHz signal BW at an Over Sampling Ratio (OSR) of 160, while consuming only 29.5-μW. And the FOMSNDR
is 180.7 dB.
Research on Ship Thrust Distribution Based on Adaptive Particle Swarm Bee Colony Hybrid Algorithm
Authors: Hou Meng , Yu Menghong , Jiao Lun
Published: April 2023

Aiming at the thrust distribution problem of nonlinear constraint in ship dynamic positioning system, an adaptive hybrid particle swarm optimization and bee colony algorithm was proposed, which was based on particle swarm optimization and bee colony algorithm, and introduced by the adaptive idea and bidirectional stochastic optimization mechanism. The optimization objective function with the minimum energy consumption and the minimum error of the thruster system was established by fully considering the thrust feasible region, the change rate of thrust and rudder angle and other constraints. Simulation results show that this algorithm can solve the thrust distribution problem reasonably and efficiently.
A method for estimating the harmonic impedance in real time based on Kalman filter algorithm
Authors: Luo Zhongyou , Hou Bing , Zhao Puzhi
Published: April 2023

Invasive and noninvasive are two common harmonic impedance estimation methods. Intrusive methods may affect the stable operation of the system. A harmonic impedance estimation method based on Kalman filter algorithm is proposed in this paper. The method adjusts the time interval of impedance estimation by selecting the frequency of sample. When the frequency of sample is high enough, it can be considered as real-time estimation of harmonic impedance.
A Novel Sliding Mode Controller Applied to SPMSM of Material Conveying System
Authors: Liu Shujuan , Jin Hui , Di Yanbiao
Published: April 2023

As an important power component of the material conveying system, the motor will inevitably cause the vibration of the mechanical structure when rotating, thus affecting the stable operation of the motor. Most material conveying systems have high requirements for motor vibration level, and usually take vibration performance and electrical performance as the evaluation criteria of the same level. A nonlinear terminal sliding mode controller is proposed to solve the phase delay and vibration problems in the sliding mode control system of surface-mounted permanent magnet synchronous motor (SPMSM) in material transmission system.. The sliding surface is an organic combination of nonlinear sliding mode and fast terminal mode, and its relative stability is verified by Lyapunov function. Through MATLAB simulation and fine comparison analysis with other advanced sliding mode control system methods, it can be seen from the simulation results that the signal of the proposed method can obviously control the noise, and the global root-mean-square error is only 1.9%, so it can be seen that the scheme is feasible..
Research on Inverter Side Control of Power Grid Simulator Based on Active Disturbance Rejection and Repetitive Control
Authors: Chen Jiawei , Xie Yuan , Jiang Jiacheng
Published: April 2023

To track the input voltage waveform quickly and accurately, and sort out waveforms on the power grid simulator, a control strategy is proposed. The first loop use repeated control (RC) and PI Control composite control, and the voltage inner loop is controlled by a first-order linear self-disturbance rejection controller (ADRC). A suitable inverter topology is also designed. To improve the performance of the proposed controller, the bandwidth method is selected to adjust the observer bandwidth. In view of the frequency adaptability of inverters on the inverter side, the output voltage imbalance is suppressed by improving the repetitive control and the tracking accuracy is improved. The simulation results indicate the controller has the ability to track the waveform quickly and accurately. In addition, the waveform jitter is effectively suppressed.
Two-stage control algorithm for magnetic fluid deformation mirror with dual-layer actuators
Authors: Guo Shuo , Fu Dongjie , Ding Haichun , Liu Tianqi , Zhou Kunhua , Iqbal Azhar , Wu Zhizheng
Published: April 2023

To increase the correction effectiveness of full-order aberration, a control system based on a magnetic fluid flexible mirror with dual-layer actuators is presented. The combined magnetic field created by the Maxwell coil and the double-layer driving coils controls the geometry of the magnetic fluid surface. A model-based optical sensorless control approach for lower layer coils is developed and aimed to enable high magnitude restoration of lower-order aberrations. An adaptive important factor that causes on Youla parameterization, on the other hand, is developed for the upper coils to rectify higher-order residual aberrations. Matlab is used to simulate the algorithm in order to test its performance in full-order aberration correction, and the results reveal that the approach has good correction performance.
Research on the Influence of UAV Anti-collision Device on Aerodynamic Shape
Authors: Li Guicong , Zuo Hongfu , Xu Juan
Published: April 2023

With the widespread use of UAVs, accidents with UAVs are inevitable. It is necessary to design an anti-collision UAV suitable for aircraft inspection. CFD simulation software is used to study the effect of adding anti-collision device on the hovering, flow field characteristics and aerodynamic shape of the UAV. The model parameters are set according to the actual situation, and the flow field characteristics of a single propeller, UAV and anti-collision UAV are simulated and analyzed in the hovering state. The analysis of the flow field determines the aerodynamic interference of the UAV anti-collision device, which provides a basis for verifying the feasibility of the design scheme.
A Low-Complexity Non-Contact Vital Sign Detection System and Heartbeat Extraction Algorithm
Authors: Yang Xiaodong , Yao Shuaiwei , Xu Xueteng , Zheng Aomei , Guo Jiachang , Wang Chao
Published: April 2023

A low-complexity vital sign detection system is proposed. The system uses a phase discriminator as the demodulation module and a phase shifter to solve the null problem in CW radar. This design significantly reduces the complexity. In the subsequent processing of this system, variational pattern decomposition (VMD) is used to analyze vital sign signals. Experiments using this system show that VMD is efficient and accurate in extracting human target respiration and heartbeat frequencies.
Automatic Retracting and Paying-off System of Tethered Unmanned Aerial Vehicle
Authors: Cheng Siyuan , Xu Gen , Xiao Jiangjian , Bu Ningbo
Published: April 2023

With the progress of unmanned aerial vehicle (UAV) technology, people have higher and higher requirements for the working endurance of rotary-wing UAVs. The tethered UAV can be wired to power through the tethered cable, which solves the problem of UAV endurance. During the descent of the UAV, the operator needs to manually rotate the take-up device for take-up manually. When the operator fails to put the redundant tied cables into the retracting and paying-off device timely, the redundant tied cables are prone to be entangled and knotted, causing potential safety hazards. To overcome the shortcomings of the above existing technologies, this project develops an automatic retracting and paying-off device based on the tethered UAV. The tension of the tethered cable is measured in real time by adding a tension monitoring unit to the traditional take-up device. According to the tension of the tethered cable and the takeoff and landing speed of the tethered UAV, the real-time automatic take-up of the tethered cable is realized.
An Indoor Real-Time Visualization Exploration Unmanned Aerial Vehicle
Authors: Bu Ningbo , Xu Gen , Xiao Jiangjian , Ge Jianfei
Published: April 2023

Aiming at the scene of a rescue in an indoor environment, this paper proposes an indoor real-time visual exploration UAV. UAVs can model the unknown space in 3D space in real-time, obtain obstacle information and flight navigation information, avoid obstacles and fly to the region of interest in real-time. Real-time transmission of three-dimensional space information to the remote end to provide rescue personnel with timely arrangements for rescue plans. The 3D mapping uses a 32-line laser radar, combining high-density point clouds and IMU to obtain accurate and real-time navigation information. The point cloud is then made into a grid map for real-time planning so that the UAV can independently calculate the flight path to the designated area. Then it is transmitted to the remote interface in real-time through WIFI communication so that the rescuers can quickly get the location and route of the rescuers needed and complete the rapid rescue operation.
Noise suppression of FMCW lidar
Authors: Geng Ziwei , Yin Longfei , Qian Dasheng , Wu Guohua , Luo Bin
Published: April 2023

Aiming at the problem that the ranging accuracy of the frequency-modulated continuous wave (FMCW) lidar decreases in the strong noise environment, experiments are carried out to verify the feasibility of the Faraday anomalous dispersion filter (FADOF) in the FMCW lidar system. The transmitter of the system uses the potassium atom vapor cell to stabilize the frequency and uses the field programmable gate array (FPGA) as the servo system. K-FADOF is used to suppress the additive noise at the receiving end of the lidar system. The results of this experiment show that the use of FADOF can successfully eliminate the interference of noise at the receiver. This experiment verifies the effectiveness of FADOF in suppressing noise in the field of FMCW lidar.
Research on path tracking control of unmanned vehicle
Authors: Wang Yunjing , Wang Jian , Yang Jun , Du Ruofei , Hai Zhenyang , Deng Huan
Published: April 2023

With the continuous progress of science and technology, driverless vehicles have become one of the development trends of automobiles in the future. Path tracking control is a key problem in the research of driverless vehicles. Based on one control theory or by combining several different theories, different control algorithms are proposed, and some achievements have been made. This paper mainly studies the tracking control research method, which is a key problem in driverless vehicles. By analyzing and comparing the LQR control method and MPC control method, we compare their advantages and disadvantages, understand the concepts and related algorithms of various path-tracking control methods, and analyze the advantages and disadvantages of various control methods.
Adaptive Dynamic Surface Control of Buck Converter Based on Energy Storage System
Authors: He Huan , Jia Yilin , Guan Qi , Wang Duo , Zhang Tianyi , Ni Yulin , Zhang Xiuyu , Zhu Guoqiang
Published: April 2023

To enhance the stability of the Buck converter and the capacity of resisting disturbance of the controller and converter, come up with an adaptive dynamic surface control strategy based on voltage mode control, which improves the ability of the energy storage system to stabilize the output voltage when the input voltage or load changes. The Radial Basis Function (RBF) neural network is combined with the finite covering lemma to approximate the unknown nonlinear functions with time-delay in the system. The error conversion and performance functions are adopted to ensure the tracking performance index. The adaptive dynamic surface controller is applied to ensure the stability of the output voltage of the system when the external conditions change. The proposed control method is tested on the hardware-in-the-loop (HIL) experimental platform. The consequence illustrate that the designed controller is feasible and has good voltage stability performance.
Design of Novel Ultra-wideband Slow-wave Microstrip Transmission Line
Authors: Yang Cheng , Wu Ruinan , Xiao Zhiliang. , Xu Wenfang
Published: April 2023

Microwave passive devices with high efficiency, small size, and light weight are one of the fundamental requirements for mobile communication coverage in the 5G frequency band. In this paper, the design of a novel ultra-wideband slow-wave microstrip transmission line is proposed and studied. The electromagnetic field simulation software HFSS is used to simulate the slow-wave microstrip transmission line, and the simulation results show that the ultra-wideband slow-wave structure has the advantage of wider bandwidth, smaller size, and lower cost, which meets the needs of 5G communication systems. Finally, the proposed slow-wave microstrip line is used in the U-shaped phase shifter, and the experimental results show that the novel slow-wave microstrip transmission line has a large application potential in the base station antenna system.
Theoretical Analysis of External Insulation of Typical Electric Equipment under Impulse Voltage and Research on Design and Verification Method of Margin
Authors: Zhang Shiling , Xiping Jiang
Published: April 2023

Lightning impulse voltage, one of the typical characteristic working conditions for assessing high-voltage power equipment, can be divided into two forms, namely full wave, and chopped wave. The external structure size of the power equipment directly depends on the lightning impulse voltage, but how lightning impulse voltage relates to the external structure size of the power equipment needs to be carefully studied. Firstly, the theoretical analytical expressions of full wave and chopped wave lightning waveforms are given from the perspective of theoretical formulas. And the lightning waveform is considered to be a polynomial superposition of exponential functions. Based on this, the discussion is divided into two typical insulation structure scenarios: 1) the verification and analysis of the space net distance of a 10 m class super long composite insulator; 2) the analysis of the relationship between the breakdown electric field strength of 5 mm tiny oil gap and oil gap spacing. Further, the lightning impulse voltage test was conducted for large hardware structures, and the corona layer mathematical model was obtained through the precise observation of the structure with the ultraviolet imager. The research shows that the lightning impulse voltage mainly checks the external insulation performance of large insulation structures such as bushings and post-insulators. For the internal oil gap duct structure of the large converter transformer, the lightning impulse voltage mainly checks the micro gap insulation strength. Lightning impulse voltage also has a breakdown effect on SF6 insulation gas, but its internal gas decomposition mechanism needs theoretical and experimental analysis urgently. The research content of this paper has certain theoretical and practical guiding value for the optimization design of large insulation structures under lightning impulse voltage.
Implementation of Channel Equalization for Large-scale Wideband Digital Array
Authors: Liu Hui , Shang Linfeng , Zhang Yuehua
Published: April 2023

Channel equalization is essential in wideband digital array radar to compensate the channel distortion and mismatch. Inverse Fourier transform (IFT) method and weighted least squares (WLS) algorithm are used to calculate the coefficients of the equalizer filter. However, the accuracy of equalizer coefficient calculation is affected by many non-ideal factors in the actual correction of large-scale digital TR channels. This paper aims to analyze the influence of various non-ideal factors in equalizer coefficient calculation and propose a test method to reduce or eliminate their influence. Finally, based on 90 channel scale FPGA-based system, the method proposed in this paper is tested and verified, and good performance is achieved.
Analysis of Communication Simulation Model of Urban Comprehensive Energy Network Based on the Internet of Things
Authors: Fang Xin , Yuan Xiaodong , Pan Yi , Shi Mingming , Yang Jinggang , Sun Tiankui
Published: April 2023

In urban construction, all energy infrastructures have been realized by the information structure. However, due to the non-uniform structure of each energy network, the data cannot be more compatible, and the communication guarantee based on the Internet of Things is one of the most urgent problems to be solved. In this paper, a reasonable network computing offloading model is designed in the edge computing layer, and the computing offloading algorithm is introduced. Considering the dependency between subtasks, an optimization problem is established, and a central scheduling algorithm is proposed to solve it. An optimized distributed unloading algorithm is proposed according to the solution idea of the classical distributed unloading algorithm. Simulation results show that the optimized distributed unloading algorithm proposed in this paper has good solving efficiency and performance, and reduces the task processing delay. At the same time, the experimental simulation proves that the efficiency of multiple edge servers in processing subtasks is higher than that of a single server. It is established that changing the convergence speed and communication delay stability margin of the system by changing the system eigenvalue is beneficial to design a better communication network structure to keep the system stable.
Node Importance Evaluation Method of Satellite Information Network Based on Heterogeneous Virtual Subnet
Authors: Li Jingling , Li Jun , Cui Tao , Liang Wei , Zhang Yi
Published: April 2023

The node importance evaluation method is of great significance for studying the robustness and routing strategies of satellite information network. According to the heterogeneous characteristics of nodes in satellite information network, they can be abstracted into two types of virtual connected nodes, and then the satellite information network model based on multi-virtual subnet is constructed. Furthermore, the node importance evaluation method based on heterogeneous virtual subnet (named HVS_based NIE) is proposed through the defined parameters such as normalization degree of virtual nodes, virtual node betweenness and correlation factor, which can accurately evaluate the node importance of satellite information network. Results of case analysis show that compared with classical graph theory algorithm, the proposed HVS_based NIE algorithm not only considers the network connectivity, but also considers the impact of data throughput on the nodes importance of satellite network, so as to evaluate the nodes importance of satellite network more accurately.
Telemetry Data Processing and Analysis Platform for Flight Test Based on Flink
Authors: Hao Mingzhe , Wang Xi
Published: April 2023

Telemetry data processing has extremely high real-time requirements in flight tests. In response to the problems faced by the traditional telemetry data processing system, such as insufficient computing capacity and low scalability, the Flink-based telemetry data processing and analysis technology is proposed to give full play to the cluster computing capacity of Flink, improve the throughput of real-time processing and reduce the processing delay. After flight test verification, the platform meets the real-time processing of multiple telemetry data and has significantly improved the stability, processing efficiency, and scalability compared with the traditional system.
Demonstration of Gd-GEM detector design for neutron macromolecular crystallography applications
Authors: Pfeiffer D. , Brunbauer F. , Cristiglio V. , Hall-Wilton R. , Lupberger M. , Markó M. , Muller H. , Oksanen E. , Oliveri E. , Ropelewski L. , Rusu A. , Samarati J. , Scharenberg L. , van Stenis M. , Thuiner P. , Veenhof R.
Published: April 2023

The European Spallation Source (ESS) in Lund, Sweden will
become the world's most powerful thermal neutron source. The
Macromolecular Diffractometer (NMX) at the ESS requires three
51.2 × 51.2 cm2 detectors with reasonable detection
efficiency, sub-mm spatial resolution, a narrow point-spread
function (PSF), and good time resolution. This work presents
measurements with the improved version of the NMX detector prototype
consisting of a Triple-GEM (Gas Electron Multiplier) detector with a
natural Gd converter and a low material budget readout. The detector
was successfully tested at the neutron reactor of the Budapest
Neutron Centre (BNC) and the D16 instrument at the Institut
Laue-Langevin (ILL) in Grenoble. The measurements with Cadmium and
Gadolinium masks in Budapest demonstrate that the point-spread
function of the detector lacks long tails that could impede the
measurement of diffraction spot intensities. On the D16 instrument
at ILL, diffraction spots from Triose phosphate isomerase w/
2-phosphoglycolate (PGA) inhibitor were measured both in the MILAND
Helium-3 detector and the Gd-GEM. The comparison between the two
detectors shows a similar point-spread function in both detectors,
and the expected efficiency ratio compared to the Helium-3
detector. Both measurements together thus give good indications that
the Gd-GEM detector fits the requirements for the NMX instrument at
ESS.
Rectifying low-frequency variability in future climate sea surface temperature simulations: are corrections for extreme change scenarios realistic?
Authors: Kusumastuti Cilcia , Mehrotra Rajeshwar , Sharma Ashish
Published: April 2023

Most procedures for redressing systematic bias in climate modeling are calibrated using current climate observations, and perform well. However, their performance in the future climate remains uncertain as no observations exist to compare against. In this context, we use the current and future climate outputs of an ultra-high resolution of Community Earth System Model (UHR-CESM) as the representative truth and bias correct monthly sea surface temperature (SST) simulations of eight Coupled Model Intercomparison Project 6 models over the Niño 3.4 region. A time-frequency bias correction approach is used to correct for bias in distributional, trend, and spectral attributes present in the models. This results in a near perfect power spectrum of the bias corrected current climate model simulations. Considering all correction procedures remain unchanged into the future, the overall representation of the corrected SST simulations shows improvement with consistency across models for the doubled CO2 scenario, but higher variability and lower consistency in the quadrupled CO2 concentration scenario.
Dynamic recrystallization behavior and processing maps of 5CrNiMoV steel during hot deformation
Authors: Li Qin , Bu Hengyong , Han Jiuyan , Li Mengnie
Published: April 2023

Hot deformation tests of 5CrNiMoV steel were performed at deformation temperatures of 700 to 870 °C and strain rates of 0.001 to 0.1 s−1 using the DIL 805D thermomechanical simulator. The critical strain and volume fraction models of Dynamic Recrystallization (DRX) were constructed based on the work hardening theory. The results showed that the critical strain of DRX decreases with increasing deformation temperature and decreasing strain rate, which implies that DRX occurs easily at higher temperatures and lower strain rates. The average DRX grain size model was established to predict grain size changes during hot deformation. Based on the hot processing maps that were constructed using the Dynamic Material Model (DMM) and microstructure observation, the optimum hot working parameters for 5CrNiMoV steel are a deformation temperature of 800 °C–870 °C, a strain rate of 0.001–0.05 s−1.
Conflict grows over the proton’s structure
Authors: Wogan Tim
Published: April 2023

New Compton scattering data has strengthened a disagreement between experiment and theory concerning the proton’s electromagnetic structure, as Tim Wogan reports.
AI simplifies calculations of electronic properties
Authors: Jarman Sam
Published: April 2023

An international team of physicists has shown that the thousands of equations needed to model a complex system of interacting electrons can be reduced to just four.
UK must boost quantum tech
Authors: Boerkamp Martijn
Published: April 2023

A new report from the Institute of Physics calls on the UK government to position the country as a world leader in the global quantum technologies market.
Decommissioned Namibian telescope to be revived
Authors: Makoni Munyaradzi
Published: April 2023

A defunct telescope at the High Energy Stereoscopic System (HESS) site in Namibia is to be refurbished and brought back online to discover and monitor variable and transient sources in the sky.
A quantum centenary
Authors: Durrani Matin
Published: April 2023

Carried out 100 years ago, the Stern–Gerlach experiment is rightly in the history books.
Standing in solidarity
Authors: Erfani Encieh
Published: April 2023

Encieh Erfani says that more must be done to support students in Iran who are risking their lives to protest against oppression.
A philosophical airing
Authors: Grozier Jim
Published: April 2023

A response to a review by Mike Follows of MichaelStrevens’ book The Knowledge Machine.
A simple guide to science
Authors: Crease Robert P
Published: April 2023

Robert P Crease reviews The Joy of Science by Jim Al-Khalili.
A practical exploration of land cover impacts on surface and air temperature when they are most consequential
Authors: Novick Kimberly A , Barnes Mallory L
Published: April 2023

Widespread shifts in land cover and land management (LCLM) are being incentivized as tools to mitigate climate change, creating an urgent need for prognostic assessments of how LCLM impacts surface energy balance and temperature. Historically, observational studies have tended to focus on how LCLM impacts surface temperature (T
surf), usually at annual timescales. However, understanding the potential for LCLM change to confer climate adaptation benefits, or to produce unintended adverse consequences, requires careful consideration of impacts on both T
surf and the near-surface air temperature (T
a,local) when they are most consequential for ecosystem and societal well-being (e.g. on hot summer days). Here, long-term data from 130 AmeriFlux towers distributed between 19–71 °N are used to systematically explore LCLM impacts on both T
surf and T
a,local, with an explicit focus on midday summer periods when adaptive cooling is arguably most needed. We observe profound impacts of LCLM on T
surf at midday, frequently amounting to differences of 10 K or more from one site to the next. LCLM impacts on T
a,local are smaller but still significant, driving variation of 5–10 K across sites. The magnitude of LCLM impacts on both T
surf and T
a,local is not well explained by plant functional type, climate regime, or albedo; however, we show that LCLM shifts that enhance ET or increase canopy height are likely to confer a local mid-day cooling benefit for both T
surf and T
a,local most of the time. At night, LCLM impacts on temperature are much smaller, such that averaging across the diurnal cycle will underestimate the potential for land cover to mediate microclimate when the consequences for plant and human well-being are most stark. Finally, during especially hot periods, land cover impacts on T
a,local and T
surf are less coordinated, and ecosystems that tend to cool the air during normal conditions may have a diminished capacity to do so when it is very hot. We end with a set of practical recommendations for future work evaluating the biophysical impacts and adaptation potential of LCLM shifts.
Homonormativity
Authors: McIntosh Dawn Marie D.
Published: April 2023

Homonormativity emerged as an interdisciplinary theory that rendered valuable understandings of power relations within and beyond the LGBTQ community. Homonormativity is a discursive and embodied practice, or set of practices, by sexual minorities that aligns with and reinforces power constructs. The transitions from macro-orientations (political strategies and movements) to microstructures (aesthetics and embodied performances) of homonormativity are arguably best located within the communication studies field. This article examines how communication studies contributes to and directs the workings of homonormativity. To accomplish that goal, the article articulates four trajectories of homonormativity: intersectional homonormativity, homonormative whiteness, transnational homonormativity, and homonormative possibilities. Embodied and/or intersectional homonormativity considers the theory of intersectionality in relationship to homonormativity. Next, homonormative whiteness details the role whiteness plays in homonormativity. Whiteness depends on the erasure of difference, and this erasure is critical to how sexually marginalized individuals as a community acquire power through racism, sexism, and classism. Homonormativity, then, is dependent on workings of whiteness to acquire power. Following this, transnational homonormativity explores the relationship between homonationalism, homo-colonialism, and homonormativity. Homonormativity is grounded in the understanding of queer bodies in relationship to nationalism, transnationalism, and xenophobia. Finally, homonormative possibilities articulates the potentialities that exist in the embodied critiques of homonormativity and possibilities provided by academic work that deconstructs it.