bluuebunny/crossref_metadata_2025 huggingface dataset:
Offloading Decision and Resource Allocation for Satellite Edge Computing
Authors: Xing Hao , Li Tong , Diao Wenlan , Wang Xiaotian
Published: June 2023

Plenty of research show that edging computing can be applied in satellite network and it has been a hotpot. By deploying the MEC server, satellites can provide enough computing resources for tasks and reduce the delay required for task processing. Compared with traditional edge computing architectures, satellite edge computing (SEC) has a greater coverage area. In this paper, offloading decisions and resource allocation in low-orbit satellites are considered and an optimization algorithm MMTORA is proposed. The algorithm decomposes the problem to be optimized into two sub-problems, and they can be solved by the Nash equilibrium solution and Lagrange multiplier algorithm, respectively. We demonstrate that MMTORA can converge quickly and prove its superiority through simulation results.
Ship Detection in SAR Images via Kullback-Leibler Divergence-Based Matrix Information Geometry Detector
Authors: Xie Zhaozhe , Cheng Yongqiang , Wu Hao
Published: June 2023

Ship detection in synthetic aperture radar (SAR) imagery is an important application in the field of marine remote sensing. As the most common method in ship detection, classical constant false alarm rate (CFAR) methods rely on the target-to-clutter contrast and accurate estimates of distribution models, making it difficult to adapt to complex and variable sea surface backgrounds. Considering the limitations of the CFAR methods, this paper proposes a new detector for ship detection based on matrix information geometry (MIG) theory. The proposed detector models each SAR sample data as a Hermitian positive-definite (HPD) matrix, and uses the geometric mean of all HPD matrices corresponding to the background window to estimate the clutter, thus transforming the target detection problem into a measure of the Kullback-Leibler divergence (KLD) between two points on the matrix manifold. Different from the traditional CFAR detectors which use intensity information to differentiate between targets and clutter, the proposed detector utilizes the intrinsic geometry of the matrix manifold and employs KLD with good differentiation to measure the variance from targets to clutter.
The Attenuation calculation method for the underwater low-frequency magnetic field of finite-length straight wire
Authors: Wang Xinyi , Jiao Yucheng , Zhang Guoguang
Published: June 2023

Usually, when solving the magnetic field distribution of a finite-length straight wire in a conducting medium, numerical calculation is required. However, this method has some disadvantages, such as complex calculations and not being conducive to engineering implementation. To solve this problem, this paper studied the attenuation calculation method for the underwater low-frequency magnetic field of the finite-length straight wire and then obtained the analytical calculation formula of magnetic field spatial distribution. The simulation results show that, within a certain distance, the analytical method is in good agreement with the numerical calculation results. The method presented in this paper is convenient for calculation and has good engineering practicability.
Portable Magnetic Detectors Based on TMR Sensors
Authors: Li Zihao , He Anran , Zhu Haobo , Wang Hai , Zhao Yinhan , Kong Xiangyan
Published: June 2023

The tunnel magnetoresistance sensor (TMR) is the fourth generation of the industrial magnetic sensor, which has the characteristics of low power consumption, high sensitivity, and low- temperature dependence. The portable magnetic detector based on the TMR sensor can effectively pick up the magnetic signal by gradient probes based on TMR sensors. After the magnetic signal is amplified, filtered, and normalized, the magnetic source orientation and amplitude are displayed on the LCD screen. The experiment proves that the portable magnetic detector can effectively detect a magnetic field larger than 100 NT at a distance of 30 cm, and the design meets the experimental requirement. It is of great practical significance to detect the magnetic source in an unshielded indoor environment.
The weak solution of quasilinear System concerning Sobolev Critical conditions in RN
Authors: Li Jing
Published: June 2023

This work treats a typical type of quasilinear system concerning critical Sobolev growth. In the light of the Lions principle and Mountain pass lemma, the mountain pass-type solutions can be derived.
Research on Radio Energy Transmission System Based on Parity-Time Symmetry
Authors: Li Zhongkui , Rong Qingfeng
Published: June 2023

Magnetically coupled resonant WPT technology can realize long-distance power transmission, which is currently a research hotspot. However, in practical applications, the position between the receiving and transmitting coils is not fixed, and its transmission power and efficiency are greatly affected by the coupling coefficient, which hinders the application and promotion of magnetic coupling resonance technology. To solve this problem, this paper proposes a magnetically coupled resonant radio energy transmission system based on parity time symmetry, designs the system structure, analyzes and explains its working principle and characteristics in detail, and finally verifies the practicability and rationality of the system through simulation analysis.
Design of Log Analysis System Based on Multi-Object Clustering Algorithm
Authors: Hao Xiaowei , Wu Hanwei , Gao Xurui , Liu Xiu
Published: June 2023

With the rapid development of the information age and the continuous expansion of data, all walks of life have begun to collect and analyze massive amounts of data to extract information that is valuable to them. Clustering technology in data mining is an important means of data analysis. Because different data sets have different distribution characteristics, traditional single-object clustering cannot adapt to the effective processing of different data sets, so multi-object clustering has gradually become a research hotspot. The purpose of this paper is the design of log analysis system based on a multi-objective clustering algorithm. This article first determines the main goals of the log analysis system and performs a detailed analysis of the system’s demanding functional analysis and demanding non-functionality respectively. The log analysis system is mainly divided into five modules for the detailed design of the log analysis system. After the system design is completed, various functional modules are completed through corresponding technologies, the entire log system is tested for attacks, and the system is further improved. Finally, the system can completely analyze the attack type through log analysis and carry out relevant early warnings to meet the needs of users. When the data set is 1.8MB, the convergence time of the K-medoid algorithm is 3678.49, and the convergence time of the algorithm in this paper is 2536.42. When the data reaches 165MB, the convergence time of the algorithm in this paper is 4326.28, and the convergence time of the K-medoid algorithm is 8184. This shows that as the scale of data continues to increase, the processing time difference changes and the processing speed of this algorithm has obvious advantages.
A distributed beamforming interference minimization algorithm based on node selection
Authors: Jia Si Yu , Hao Wen Hui , Wang Xing Jian
Published: June 2023

Distributed beamforming uses nodes in a wireless sensor network to transmit signals in different phases with controllable delay, to obtain coherent output signals with a gain after superposition. However, a wireless sensor network has a large topological area and wide distribution range, and it is difficult for distributed beamforming to obtain a highly directional beam as centralized beamforming does, which will cause interference to the non-target base stations. To solve this problem, a discrete adaptive dual-population cooperative differential evolution (DPCDE) algorithm is proposed, which can effectively reduce the interference by selecting nodes suitable for participating in distributed beamforming in a wireless sensor network. Simulation results show that the proposed algorithm can optimize the node set participating in distributed beamforming to minimize the interference of the wireless sensor network to the non-target base stations, and the effect is better than other classic intelligent optimization algorithms.
A High Precision Joint Time Synchronization and Location Algorithm for Moving Target
Authors: Liu Yufei , Huang Jiyan , Liu Zhiyuan , Tan Yanmin , Kuang Zhendong
Published: June 2023

Time synchronization is the guarantee of normal operation of wireless sensor networks, and it is the premise of ranging and location. At present, most researches focus on joint time synchronization and location of non-moving targets, while there are few types of research on joint time synchronization and location of moving targets. Therefore in this paper, under the condition that the time synchronization of the moving target is not carried out, and the information measurement means such as the speed and position of the moving target are not available. We established the system model of joint time synchronization and location with the help of the anchor nodes whose clock has been synchronized and location is known, and derived the Cramer-Rao lower bound (CRLB) of the system. Then we proposed the two-step least square method and iterative method. The former has lower computation and suboptimal performance, while the latter has higher time synchronization accuracy and positioning accuracy, which can attain CRLB. The results are verified by simulation.
Broadband THz Edge-Enhanced Imaging Technology Based on Electro-Optic Sampling
Authors: Yuan Xingming , Li Ying , Lin Qinggang , Chen Jiapin , Cai Yi , Xu Shixiang , Li Jingzhen
Published: June 2023

Based on the radial Hilbert transform of spatial filtering and electro-optical sampling, we propose a broadband terahertz edge-enhanced imaging method in this work. Instead of using a narrow-band THz vortex phase plate, here we use vortex ultrashort laser pulse to realize the THz enhancement imaging which can be applied for few-cycle THz imaging. The principle of edge enhancement is analyzed theoretically, and the analytical expression of the final terahertz imaging is derived. We found that edge-enhancement imaging corresponds to the nonlinear term of the THz field, and the background and linear terms can be suppressed when the static birefringent phase is set to zero. The simulations show that our method can effectively improve the contrast and signal-to-noise ratio of terahertz imaging.
Random Multi-access Scheme Based on Group Testing Theory for Massive Machine-type Communication
Authors: Wang Hong , Liu Xiangyang , Xie Yunhong , Xu Xiaotao
Published: June 2023

Considering emerging massive machine-type communication with very few devices simultaneously transmitting short messages, random multiple access has currently become a research hot spot since the traditional multiple access protocol struggles to work properly. Inspired by the superimposed code, a channel assignment scheme based on non-adaptive group testing theory is proposed to allow multiple users to share a single channel at the same time. A superimposed code with threshold value d, which can recover the original code through the Boolean sum of up to d codes, is constructed by studying the problem of group testing. When the number of active users with a message to be transmitted is no more than the threshold value, active users encode their messages by the superimposed code and multiple active users transmit their messages together by sharing a single channel. The receiver can decode the mixed messages by the disjunction of the superimposed code. We focus on the design of the superimposed code by group testing theory, formulate this problem as the construction of a transversal design, and use the Latin square to form a useful transversal design. Theoretical proof shows that our design works well under limited circumstances where the number of active users does not exceed the threshold value. Additionally, our design can recover the original codes by the mixture of codes, which are more easily than the algorithms based on compressive sensing. Simulation analysis presents that our design performs better than the traditional competitive access protocols in terms of successful probability, throughput, and packet loss rate.
Preparation of Hydrophilic Antifogging Film Materials by Silicate Minerals
Authors: Wei Shenyu , Wang Lei , Peng Cheng , Zheng Qi , Cui Xinglan , Che Xiaokui , Yu Zeen
Published: June 2023

Silicate minerals are widely used as green, nontoxic, low-cost materials. In this experiment, hydrophilic antifogging films of silicate minerals were prepared by the vacuum evaporation coating method. The hydrophilicity, antifogging performance, optical properties, and surface morphology of the film materials were analysed and characterised by the contact angle meter, the hydrothermal method, the ultraviolet-visible spectrophotometer, and the atomic force microscope, respectively. The results show that the contact angle of the prepared mineral hydrophilic antifogging film is less than 25° and is hydrophilic. When the thickness of the film is 100–200 nm, the antifogging effect is the best. As the thickness increases, the antifogging effect weakens. The film material has little effect on the transmittance of the substrate. When the film thickness is 100 nm, the maximum transmittance is 92.2%, which is 4.5% higher than the uncoated substrate and has some effect on increasing the transmittance. With the increase of film thickness, the mineral material nanoparticles gradually accumulate densely on the substrate surface, and the roughness of the sample surface decreases, which leads to the decrease of hydrophilic properties and antifogging performance of the film.
Lithium storage properties of Sn/C composite anode materials
Authors: Huang Zhaowen , Huang Chuting , Li Youpeng , Zhao Lingzhi
Published: June 2023

In this paper, tin-carbon composites were prepared by the hot carbon reduction method and used as anode materials for lithium-ion batteries. The results show that the hot carbon reduction method can effectively reduce SnO2 to spherical metallic tin, and the excess of carbon affects the size and shape of tin spherical particles. The higher the tin content is, the higher the lithium intercalation potential of the anode material is. The improvement of cyclic stability of tin-carbon composites is at the expense of reversible capacity. The core-shell structure of pitch pyrolysis carbon can effectively inhibit the reversible capacity decay caused by tin volume expansion.
Effect of Cobalt Content on the Properties of Nickel-Cobalt Alloy Coatings
Authors: Wang Yunhuan , Liu Quan , Ding Mingli , Li Hongao , Yang Songru , Guo Cean , Zhang Jian
Published: June 2023

A batch of nickel-cobalt alloy coatings was pulse-electroplated on gun steel (PCrNi3MoVA) surface, in which weight fractions of Co element are 39.9 %, 55.5 %, 67.5 %, and 79.8 %, respectively. The formations of phase and crystal structure in nickel-cobalt coatings were investigated by X-ray diffraction analysis. The layers’ surface morphology and chemical composition were analyzed by scanning electron microscopy coupled with energy dispersive spectrometry. The tribological and nano-mechanical performances of the coatings were used to evaluate by high-speed reciprocating friction and wear tester and nanoindentation tester, respectively. The results showed that the preferred orientation of the coatings gradually changed from (111) to (220) with the rising cobalt content, resulting in changes in the surface morphology of the coatings from pyramidal grains to spherical particles and then to a triangular pyramid structure. As the Co content was 55.5 wt.% in the nickel-cobalt coating, its crystalline grain size reached the smallest value of 11.53 nm, enhancing the hardness and wear resistance.
Flow Characteristics of Orifice Plate in Vertical Multistage Flash Evaporator for Waste Heat Recovery
Authors: Sun Yifan , Yan Huaizhe , Wang Lin , Shen Haihua , Xu Ziyun , Fang Fenglei , Li Haoran , Li Hui
Published: June 2023

A vertical multistage flash device uses orifice plates as pressure isolation devices, so wastewater flows from the upper stage to the next stage by its gravity, which can significantly lower the system’s surface area. To study the resistance characteristics of the flash flow during wastewater flowing through the pressure isolation device, a flow and flash model for the wastewater in an orifice was developed and the corresponding flash process was numerically investigated by FLUENT. The effects of the inlet temperature of wastewater, flash pressure, and orifice thickness on the flash were analyzed. The results show that the closer to the orifice outlet we are, the lower the temperature of wastewater and the larger the vapor volume fraction become. While the temperature is lower, the vapor volume fraction is larger near the orifice wall than it is towards the center. While the temperature reduction of wastewater is not immediately apparent, the vapor volume fraction in the orifice increases as the pressure differential between the orifice’s input and output increases.
The corrosion behavior of TA1 and TC4 in Proton Exchange Membrane Water Electrolyzers
Authors: Huang Yao , Yue Luo , Chang Liang , Zhang Gaoqun , Hu Xiao , Xu Guizhi , Deng Zhanfeng , Mao Hangyin , Feng Jia
Published: June 2023

Titanium Bipolar Plates (BPPs) are frequently utilized in Proton Exchange Membrane Water Electrolyzers (PEMWE) nowadays since they could endure the challenging working environment. Notably, the extreme anodic potential and acidic environment of the PEMWE are extremely critical for BPPs’ performances. In this study, we explored the corrosion behaviors of conventional titanium alloys of TA1 and Ti-6Al-4V (TC4) at simulated operating conditions. To evaluate their corrosion behaviors, potentiodynamic polarization, electrochemical impedance spectroscopy, and potentiation, polarization experiments were executed. Additionally, scanning electron microscopy (SEM) was applied to detect the morphologies before and after the electrochemical measurements. Finally, the corrosion mechanisms of TA1 and TC4 were analyzed and discussed by X-ray photoelectron spectroscopy (XPS). After 7 days of potentiostatic polarization, the corrosion current density of TA1 remained at 3×10−8 A·cm−2, which was nearly one order of magnitude lower than that of TC4. These experimental data confirmed that the TA1 alloy had superior corrosion resistance to the TC4 alloy during long-term running in PEMWE operating conditions.
Scheduling optimization of wind-solar power generation system based on Power to Gas
Authors: Wang Zhengtai , Wen Fawei
Published: June 2023

Storage technology and consumption technology can reduce the amount of abandoned wind and sunlight, improve the utilization of new energy, and reduce cost. Firstly, this paper describes the role of P2G (Power to Gas) technology in the field of new energy consumption, then builds the economic cost-optimal day-ahead optimal dispatch model based on a microgrid, examining the ability of P2G devices to consume new energy. Finally, three different scenarios are applied in the example for verification. The calculation example proves that P2G devices have a good effect in the field of scenery consumption and reduce the cost of the microgrid.
Design of Practical Engineering Strategies for Stabilizing Perovskite Solar Cells
Authors: Liu Yuxuan
Published: June 2023

Perovskite solar cell (PSC), as an efficient and economic-friendly way of converting sunlight into electrical energy directly, has been developed fast in recent decades. Despite promising performance parameters, its long-term chemical stability is presently identified as the most crucial challenge hindering practical application and commercialization, preventing future developments. Recent research showed that introducing materials with suitable traits, and alternating structures of interfaces are important in slowing degradation rates. To illustrate a comprehensive picture of up-to-date strategies taken by different researchers in enhancing PSC durability, this review divides the strategies into five categories: material hydrophobic properties, easing ion migrations, slowing degradation reactions, enhancing molecular chemical interactions, and reducing surface defects, which are five pathways that may lead to more useful interventions in the future.
Experimental Study on Removal of Gaseous Arsenic by CuO/TiO2 Catalyst
Authors: Zhang Bowen , Wu Jiang
Published: June 2023

The emission of arsenic from thermal power plants poses many hazards to humans and the environment, so controlling arsenic emissions is an urgent problem to be solved. This paper prepared CuO/TiO2 adsorbent by selecting TiO2 with a large specific surface area as the substrate. The adsorption performance of CuO, TiO2, and CuO/TiO2 adsorbent materials on gas-phase arsenic at different reaction temperatures (500 °C, 600 °C, and 700 °C) was investigated. The experimental results showed that CuO/TiO2 adsorbent had better arsenic adsorption capacity than CuO and TiO2 because CuO/TiO2 has a large specific surface area and rich surface-active sites. The temperature affects the performance of the adsorbents, and all three adsorbents do not perform well at 700 °C, mainly because the metal oxide materials are not resistant to high temperatures, and the mesoporous structure is easily collapsed. CuO/TiO2 adsorbent is suitable for the control and emission reduction of heavy metal arsenic in coal-fired flue gas at medium and low temperatures below 600 °C. The above study provides a direction for developing and applying adsorbents to remove gas-phase arsenic.
Surface Geometry, Electronic and Thermodynamic Properties of SrCeO3 (001): First-Principles Calculation
Authors: Li Qingjun , Lu Haotian , Yang Kun
Published: June 2023

This study uses first-principles density functional theory (DFT) to calculate the SrCeO3 (001) surface with CeO and SrO2 terminals. The influence of vacuum layer thickness on the geometric structure and energy stability is studied. The calculation by Materials Studio software shows that the surface with SrO as the terminal has obvious surface wrinkles compared with the surface with CeO2 as the terminal. The surface stability evaluation shows that the SrO termination surface is more stable in energy than CeO2. The band gaps of CeO2 and SrO terminals were determined to be 0.971eV and 1.733eV, respectively, which were smaller than those of SrCeO3 protocells.
Preparation of Azophenyl Photo-Induced Phase Transition Polymer and its Study on Adhesion Property
Authors: Chen Longxuan , Gong Piwen , Mu Jiahui , Zhao Ruiyang
Published: June 2023

The design and synthesis of photo-induced reversible adhesives are considered to be the solution to the problems of traditional adhesives in separating, recycling, and repairing. We have designed and synthesized an azophenyl copolymer (PNY-Azo) with photo-induced phase change properties. The adhesion strength of PNY-Azo varies greatly between trans conformation (solid-state) and cis conformation (liquid state), which is suitable for photo-induced reversible adhesives application due to the reversible photo-induced bonding/debonding process between two substrates. By increasing the number of oxygen atoms on the side chains of the copolymer, the supramolecular interaction (H bond) between the copolymer molecular chains and the entanglement of copolymer chains are improved, which can be enhanced the adhesion strength (up to 4.59 MPa) of trans conformation PNY-Azo effectively.
Combustion Characteristics of Diesel Methanol Blended Fuel Ship Engines
Authors: Ma Jun , Li Chunjin , Li Lei , Zhang Zengxin
Published: June 2023

With increasingly stringent fuel emission control in some river traffic control zones and inland waters, this paper addresses the problem of substandard diesel fuel emissions, relying on the theoretical basis of numerical simulation of diesel engine in-cylinder combustion. The combustion and emission characteristics of diesel-water-mixed methanol blended fuel are simulated and analyzed based on the AVL FIRE software. The combustion model of the diesel engine was established, and the changes of in-cylinder pressure, temperature, heat release rate, and emission concentration were investigated for D85W10, D85W15, and D85W20 blends respectively, which were compared with diesel. The results show that as the proportion of water in the fuel mixture increases, the in-cylinder temperature gradually increases, the in-cylinder pressure slightly decreases, the heat release rate does not change much, and the NO and Soot emissions decrease.
Electropolishing Behavior of 8xxx Al Alloy in Perchloric Acid and Ethanol Solution
Authors: Zhang Linhui , Zhong Binnian
Published: June 2023

The electropolishing characteristic curves of rolled 8079 Al alloy in perchloric acid and ethanol solution from -25 °C to 25 °C are obtained. The optimal electropolishing conditions of the 8079 Al alloy with rolled are investigated by optical microscope. The result shows that the lower the electropolishing temperature is, the longer the electropolishing time is, and the time range and voltage range are wider. Furthermore, the calibration rate of the phase after electropolishing is higher than 97% investigated by Electron Back-Scatter Diffraction. The electropolishing effect of both 8079 Al alloy with cast and 8011 Al alloy (cast and rolled) is verified.
Preparation of High Specific Surface Area Activated Carbon from Semi-Coke for Carbon-Based Supercapacitor Applications
Authors: Li Sai , Zhang Jinkui , Han Jinjin , Liu Kai , Wu Yan
Published: June 2023

With the continuous development of energy storage technology, a device between ordinary capacitors and batteries, with low cost, high performance, and no pollution, is attracting a lot of attention. Common supercapacitors are generally composed of four parts, of which the electrode material as a core part determining the performance of the capacitor, should be selected reasonably. Currently, the most commercially mature electrode materials are still dominated by porous carbon materials. In this paper, we prepared activated carbons with a high specific surface area by a simple chemical activation method using semi-coke, a derivative of coal after dry distillation, and activated at 800 °C. The prepared activated carbons had a specific surface area of 2522 m2g−1 and a pore capacity close to 1.5 cm3g−1. Moreover, the prepared supercapacitors showed excellent specific capacity and better multiplicative performance. This work provides a new inspiration for the preparation of high-performance activated carbon from low-cost semi-coke.
The Performance of SiO2 Nanofluid-based Split-frequency PV/T Energy
Authors: Nie Binghan , Qiu Zhongzhu , Zhang Yunpeng , Ni Xingrui , Zhang Miaomiao , Xu Ning
Published: June 2023

The efficiency of both solar photovoltaic and thermal power generation is relatively low, with the maximum panel temperature of conventional PV/T modules reaching 68.4 °C at noon, and the average electrical efficiency is only 12.98%. In this paper, the energy performance of a PV/T module based on SiO2 nanofluid was studied. Firstly, three different types of nanofluids, SiO2 nanofluid with a mass fraction of 0.3%, mass fraction of 0.5%, and mass fraction of 0.7%, were prepared and tested for their solar spectrum transmittance, and the results manifested that only the SiO2 nanofluid with 0.5% mass fraction exhibited strong absorption characteristics in the band after 400–1150 nm. Three liquid film thicknesses of 5 mm, 10 mm, and 15 mm, and three nanofluid mass fractions of 0.3%, 0.5%, and 0.7% were selected for the calculation of the spectral transmittance and the experiments on the thermal efficiency of the whole PV/T module. After conducting twenty-minute experimental tests on the power generation efficiency, thermal efficiency, and panel temperature of the flat panel, the results turned out the maximum efficiency reached 52.19%, which was found at a liquid film thickness of 10 mm and a nanofluid mass fraction of 0.7%, with a lower temperature of 40 °C, and an average of 10 °C lower than conventional PV panels.
Experimental study on the photocatalytic oxidation of mercury in flue gas with a nano-flowered photocatalyst
Authors: Qin Zhiwei , Wu Jiang
Published: June 2023

To solve the scientific problem of efficient removal of singlet mercury from coal combustion flue gas, we propose to combine it with photocatalytic technology. We have successfully synthesized a novel photocatalytic material by growing iron oxide nanoparticles in situ on the surface of bismuth tungstate material and analyzed the physicochemical properties, chemical composition, morphological structure, and optical properties of the material by XRD, SEM, TEM, EPR, and UV characterization methods. Heterojunctions and oxygen vacancies were constructed to achieve efficient photocatalytic oxidative removal of singlet mercury. The mechanism of action of the enhanced photocatalytic performance is described to provide a feasible solution for the future preparation of photocatalytic materials with high catalytic activity.
Study of Loss Reduction and Network Planning of a High Proportion Distributed Generation System
Authors: Liang Chen , Ma Yanhong , Ma Xiping , Bao Chengjia , Han Xushan
Published: June 2023

In order to realize a “double carbon” goal, it is necessary to further conserve energy and reduce emissions on the power grid. The high proportion of distributed generation dramatically impacts the power system network loss. Distributed generation connected to the distribution network is dependent on its location and capacity. In this work, distributed generation location and capacity are optimized by considering investment and operation costs, active power loss, and voltage security. Based on the particle swarm optimization algorithm, the 9-bus system is optimized and analyzed. It is found that (1) for the radial distribution network system, the closer the access location of the distributed generation is to the end of the load, the smaller the line loss of the system; (2) with the increase of DG load capacity ratio, the overall network loss of the system will first decrease and then increase. Furthermore, the IEEE standard 33 bus distribution network system is further optimized and simulated in this study. It is demonstrated that the proposed method reduces network losses and improves voltage quality.
A Short-term Electricity Load Forecasting Method Based on WOA-BiLSTM-Attention
Authors: Song Qian , Lan Junhuan , Luo Fugui , Li Mingzhen
Published: June 2023

Under the “double carbon” policy, it is time to build a new green and safe power system. Special attention should be paid to the low accuracy in short-term power load prediction. Therefore, this paper presents a technique for anticipating short-term power demand based on a bidirectional long short-term memory network with a whale-optimized attention mechanism (WOA-BiLSTM-Attention), which is used to forecast and analyze the measured power values in a certain area. The experimental findings reveal that the suggested technique has much greater prediction accuracy and convergence speed, as well as superior stability, when compared to LSTM, BiLSTM, and BiLSTM based on attention mechanism, making it a good reference for power system planning and stability.
A Short-term Power Load Forecasting Method Based on An Improved VMD-LSTM Algorithm
Authors: Liu Leijia , Chen Ping , Wang Yanbing , Han Lu
Published: June 2023

Accurate power load prediction is a crucial basis to ensure the balance of power supply and demand. This paper provides a modified variational modal decomposition (VMD) - long short-term memory (LSTM) algorithm, using genetic algorithm (GA) to iteratively optimize the number of decomposition layers and penalty factor parameters, and using VMD to obtain the modal components, fuse them with the filtered features. Then the reconstruction data is obtained through normalization according to the parameters of the original load characteristic data set. Finally, LSTM is constructed to excavate temporal characteristics and obtain power load prediction results. Simulation fully demonstrates the superior performance of this modified model in terms of prediction effect.
Research on the Inspection Method of Extra High Voltage Grid Based on 3D Model Fusion
Authors: Fu Chengcheng , Liu Jun , Sang Peishuai
Published: June 2023

The current traditional grid inspection method eliminates potential hidden problems of the power system by ranking fault points, but the lack of extraction and fusion of grid scene features leads to poor inspection results. In this regard, a three-dimensional model fusion-based inspection method for an extra-high voltage power grid is proposed. The key motion metric function is defined by calculating the local minima. And the 3D model is constructed to extract and fuse the UHV grid scene feature data, and finally, the path of UAV inspection is planned. In the experiment, the inspection performance of the proposed method is verified. The analysis of the experimental results shows that when the proposed method is used to inspect the extra-high voltage grid, the KRS index value is high and has a more excellent UAV inspection path planning capability.
Reactive Power Control and SVG Coordinated Control Method for HVDC Transmission System
Authors: Zhong Qidi , Ma Yulong , Li Zhichuang , Lu Yajun , Li Ming
Published: June 2023

This paper proposes a reactive power and SVG coordinated control method for a HVDC transmission system. The method includes calculating the reactive power ΔQ exchanged between the converter station and the AC system. Set the dead zone range of ΔQ and limit the output of ΔQ. Set the restriction condition of SVG’s ability to adjust and judge whether the reactive power emitted by SVG is restricted. Based on whether the reactive power sent by the SVG is limited and the limitation results of ΔQ, the input of the PI controller in the QPC module is calculated to complete the reactive power, and SVG coordinated control process. When this control method is adopted, the operating time of the converter greater than the rated angle is significantly reduced, the loss of the converter is effectively reduced. Meanwhile, the DC voltage rise and fall are stabilized, and the AC voltage fluctuations due to the passive switching are greatly reduced.
An Early Warning Method of Transmission Line Icing Based on Power Grid Meteorological Monitoring Data
Authors: Zhang Yi , Zhang Feng , Qiu Yutao , Wu Yifeng , Liu Ang , Mo Jianguo , Xie Xiahui
Published: June 2023

The icing of conductors may seriously affect the safe operation of the power grid, and it is imminent to research the early warning of icing of the power grid. This paper innovatively cites a mesoscale digital-intelligent weather forecast technology considering the influence of micro-topography and combining the power grid meteorological monitoring data to realize the monitoring and early warning of icing on the transmission line of the provincial power grid. The accuracy of the icing forecast can be improved through the interpolation correction of micro-topographic factors and the statistical correction of meteorological monitoring network monitoring. The study has achieved remarkable results in realizing precise line inspections and scientific ice-melting decision-making, enhancing the ability of power grid ice disaster prevention and mitigation, and has important theoretical significance and engineering application value for improving power grid security.
Optimal Dispatch of Distribution Networks Based on Energy Storage Systems and Integrated Demand Response in Lightning Climates
Authors: Wang Tao , Liu Zhaoguo
Published: June 2023

Lightning weather is a type of strong convective weather that is an important factor in causing faults in the operation of the distribution network, which can lead to widespread power outages. The application of PV and energy storage systems further mitigates the losses caused by lightning-struck outages. In the paper, firstly, the uncertainty model of lightning strike probability and contact line power loss is established based on the irradiation intensity and the expected value of power losses is calculated using sequence operation theory. Secondly, considering the cost of load loss, an optimal dispatching model of the distribution network based on opportunity-bound planning is constructed to minimize system operation costs, and the impact of different operation strategies on power loss in the lightning context is explored in depth. The proposed method allows for a trade-off between the economy and the reliability of the distribution network in the lightning context by setting suitable confidence levels. Finally, the model is solved using the CPLEX solver, and the accuracy of the proposed model and dispatching strategy is verified by an improved IEEE33 system example.
Design and Implementation of Hardware in the Loop Simulation Test Platform for Photovoltaic Inverter
Authors: Liu Shaojie , Zhao Yingying , Li Wenhe , Cheng Yuanchu
Published: June 2023

In order to ensure the performance and safety of photovoltaic grid connected inverter, based on hardware in the loop simulation technology, the design and implementation of photovoltaic grid connected inverter simulation and test platform are discussed. The system structure, principle and main functions of the platform are introduced. The simulation and test platform is composed of simulation and monitoring computer, simulation and measurement interface device, programmable power supply and test instruments. In the platform, the programmable DC power supply, the programmable AC power supply and RLC load is used to simulate the characteristics of solar panels, power grid and load respectively. The test process is controlled by LabWindows/CVI software interface, and the test data collection is completed through power quality analyser, power analyser, oscilloscope and simulation and measurement interface device. The simulation test software completes the data analysis and realizes the full-automatic detection of the grid connected inverter. The established hardware in the loop simulation test platform of photovoltaic grid connected inverter has the ability to conduct comprehensive test and detection of photovoltaic grid connected system, which can be used to verify and evaluate the photovoltaic inverter before it is connected to the power grid.
Design of Reactive Power Online Monitoring System of Intelligent Distribution Transformer Based on Edge Computing
Authors: Huang Fu , Lin Junhong , Zhang Daolu , Wu Dan
Published: June 2023

Due to the unbalanced development of various regions, in most regions, the distribution transformer of medium voltage line has not realized automatic monitoring, so the staff cannot monitor it in real-time. Therefore, an online monitoring system for the reactive power status of intelligent distribution transformers based on edge computing is designed. The system hardware structure configuration consisting of the master station layer, the edge layer and the acquisition layer is constructed, and the system software functional structure consisting of data processing, online monitoring, and system management is designed. On this basis, the continuous sampling data of the reactive power of the intelligent distribution transformer is collected, and based on edge computing, the reactive power operation characteristics of the intelligent distribution transformer are obtained and matched to judge the reactive state of the intelligent distribution transformer operation, so as to realize online monitoring of the reactive state of the intelligent distribution transformer. The experimental results show that the online monitoring accuracy and efficiency of the intelligent distribution transformer reactive state are high.
A fully digital power supply system for TLS corrector magnets
Authors: Wang Baosheng , Liu Kuobin , Liu Chenyeo , Wong Yongseng
Published: June 2023

This study focuses on the development of a fully digital power supply system (FDPSS) for
the Taiwan Light Source (TLS) storage ring corrector magnet, which includes the fully digital
correction power supply (FDCPS), digital communication card (DCC), and a virtual operation
interface. The DCPS adopts a full-bridge circuit architecture, with the TI TMS320F28335 digital
signal processor (DSP) as the core, combined with an 18-bit high-resolution A/D converter and
discrete PID algorithm to achieve closed-loop current control, ensuring a stable output current
value of the system. The DCC can control eight DCPS modules through an RS485 protocol with a
virtual instrument control interface. This new system can replace the analog signal-modulated Bira
MCOR30A power supply system, which has been in operation for 25 years in the TLS storage ring and
can be upgraded to an FDPSS. This article aims to discuss the design concepts, hardware
implementation, and testing of FDCPS and DCC to demonstrate the advantages of full digital control
and to achieve the goal of independently researching and developing the prototype of
FDPSS. Ultimately, after long-term testing and verification, the system's output current stability
is less than ± 20ppm, indicating that this new system has high-precision and high-stability output
current characteristics. In this study, upgrading the TLS storage ring corrector magnet power
supply system to full digital control significantly improves output current stability and accuracy.
Environmental risks and opportunities of orphaned oil and gas wells in the United States
Authors: Kang Mary , Boutot Jade , McVay Renee C , Roberts Katherine A , Jasechko Scott , Perrone Debra , Wen Tao , Lackey Greg , Raimi Daniel , Digiulio Dominic C , Shonkoff Seth B C , William Carey J , Elliott Elise G , Vorhees Donna J , Peltz Adam S
Published: June 2023

Hundreds of thousands of documented and undocumented orphaned oil and gas wells exist in the United States (U.S.). These wells have the potential to contaminate water supplies, degrade ecosystems, and emit methane and other air pollutants. Thus, orphaned wells present risks to climate stability and to environmental and human health, which can be reduced by plugging. To quantify environmental risks and opportunities of well plugging at the national level, we analyze data on 81 857 documented orphaned wells across the U.S. We find that

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4.6 million people live within 1 km of a documented orphaned well. 35% of the documented orphaned wells are located within 1 km of a domestic groundwater well, yet only 8% of the wells have groundwater quality data within a 1 km radius. Methane emissions from the documented orphaned wells represent approximately 3%–6% of total U.S. methane emissions from abandoned oil and gas wells, but this estimate is based on measurements at

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0.03% of U.S. abandoned wells. 91% of the documented orphaned wells overlie formations favorable for geologic storage of carbon dioxide and hydrogen, meaning that orphaned well plugging can reduce leakage risks from future storage projects. Finally, we estimate plugging costs for documented orphaned wells to exceed the $4.7 billion federal funding by 30%–80%, emphasizing the importance of prioritizing federal spending on wells with large remediation benefits. Overall, environmental monitoring data are not extensive enough to quantify risks, especially those related to air and water quality and human health. Plugging orphaned wells can provide opportunities for geologic storage of carbon dioxide and hydrogen and geothermal energy development, thereby facilitating efforts to transition to net-zero energy systems. Our analysis on environmental risks and opportunities of orphaned wells provides a framework that can be used to manage the millions of documented and undocumented orphaned wells in the U.S. and abroad.
Isotropic N-point basis functions and their properties
Authors: Cahn Robert N , Slepian Zachary
Published: June 2023

Isotropic functions of positions

r

1

,

r

2

,
…
,

r

N

, i.e. functions invariant under simultaneous rotations of all the coordinates, are conveniently formed using spherical harmonics and Clebsch–Gordan coefficients. An orthonormal basis of such functions provides a formalism suitable for analyzing isotropic distributions such as those that arise in cosmology, for instance in the clustering of galaxies as revealed by large-scale structure surveys. The algebraic properties of the basis functions are conveniently expressed in terms of 6-j and 9-j symbols. The calculation of relations among the basis functions is facilitated by ‘Yutsis’ diagrams for the addition and recoupling of angular momenta.
Prediction of Exhaust Gas Temperature of a Diesel Engine Running with Diesel Fuel-biodiesel-1-pentanol Ternary Blends
Authors: Gülüm Mert
Published: June 2023

Diesel engines are utilized in the transportation sector owing to their high efficiency. In recent years, biodiesel and higher alcohols have taken the attention of researchers as promising alternative fuels for diesel engines. In this article, diesel fuel is mixed with corn oil biodiesel at the ratio of 80:20 (v/v). 2%, 5% and 8% of 1-pentanol (v/v) are mixed into the diesel fuel-corn oil biodiesel binary blend for obtaining ternary blends. The impacts of ternary blends on some performance and combustion behaviors of a diesel engine are researched. Power and exponential models to predict exhaust gas temperature linking to maximum pressure rise rate, brake effective power, lower heating value, engine speed, equivalence ratio and latent heat of evaporation are derived through the least square error method. The use of ternary blends results in lower brake effective power (5.4246%-6.0066%), exhaust gas temperature (5.9504%-7.9459%,) and peak cylinder pressure (6.8502%-7.1629%), compared to diesel fuel. The average relative errors are specified as 1.9214% and 2.9749% for the power and exponential models, respectively.
Investigation on Water Pollution Control of Drinking Water Source in China
Authors: Huang S J , Zhou G Q , Tang Y D , Wei J
Published: June 2023

Drinking water source is an important guarantee of domestic water for urban residents, which has been affected mainly by non-point pollution and aroused widespread concern in various countries. However, with the change of underlying surface types, there are significant differences in pollution control strategies. In this study, two pollution control strategies were proposed for two typical underlying surface conditions with high-density built-up water source and agricultural water source, respectively. It is considered that the high-density built-up area can be divided into ecological area and built-up area. The stormwater runoff from ecological area is intercepted and transferred to reservoir directly. But the stormwater runoff from built-up area are treated in three situations: rainfall less than 7 mm, rainfall greater than 7 mm and less than 50-year return period and rainfall greater than 50-year return period. Correspondingly, the intercepting ditch, embedded ecological reservoir, constructed wetland and deep tunnel are applied. Differently, for agricultural water source, the strategy of land right circulation can be taken to reduce domestic pollution and pesticide pollution. Further, the pollution load entering the reservoir is reduced by near-natural wetland, ecological isolation zone and floating debris interception. At the same time, with the help of superior natural resources, ecological industry can be developed to achieve balance of protection and development based on EOD. The research results can provide valuable reference for the treatment of non-point source pollution reservoirs.