bluuebunny/crossref_metadata_2025 huggingface dataset:
Research on the Hydropower Coupling-Based Hydropower Station Scheduling Optimization Model
Authors: Liming XIA , Yanmei ZHU , Chunyang LAI , Weibin HUANG , Shijun CHEN , Jinlong WANG
Published: August 2021

In order to improve hydropower availability and give full play to its power generation capacity, it is of great significance to set up a feasible and efficient scheduling optimization model. Based on the hydropower output match relation, the coupling factor and coupling are put forward. These two notions will be taken as the restriction condition. The hydropower station scheduling optimization model has been established by taking the minimal deviation of fulfillment of sales objective as the target function. Based on example of Dagangshan hydropower station in the Dadu River area, the model algorithm of particle swarm optimization algorithm is used for validation. According to the empirical study, the model doesn't produce discarded water during power generation, compared with the comparison schedule. Besides, it has more daily power output and smaller deviation of daily sales target power generation, which can effectively guide the economic operation of Dagangshan hydropower station.
Simulation calculation and analysis of energy-saving and efficiency-increasing of thermal power plants reform project
Authors: Li Lin , Gao Yan , Dou Huawei , Luan Tao , Cao Qing , Li Yanteng
Published: August 2021

Taking the third stage of National Energy Group Shengli Power Plant project as an example, the application effects of a number of hybrid transformation measures on the heat consumption of steam turbines were calculated, and the heat consumption of the unit was used as the characteristic value to compare the energy-saving benefit of various transformation measures. The results show that, there is a positive correlation between back pressure optimization and other energy-saving transformation measures, which can enhance the efficiency improvement effect of joint transformations. Among the three and four retrofit measures, data verification found that the ranking of the heat consumption benefits caused by individual retrofit measures: back pressure optimization retrofit> full cylinder efficiency retrofit> waste heat utilization retrofit> low pressure cylinder efficiency retrofit> medium pressure cylinder efficiency improvement transformation> high pressure cylinder efficiency improvement transformation> external steam-cooling transformation.
Research on Energy Storage and Hydrogen Production System of Offshore Wind-solar Hybrid Power Generation Based on 3D Finite Element Method
Authors: Wenli Li
Published: August 2021

At present, hydrogen, as a fuel, has the characteristics of high efficiency and no pollution, which can replace traditional fossil energy and be used in various fields to a certain extent. Using clean energy such as wind and light to electrolyze water to prepare hydrogen can realize zero pollution in the whole process from hydrogen preparation to use. Such energy conversion and use can reduce air pollution, improve air quality and solve the problem of abandoning wind and light. In this paper, a simulation model is established by using threedimensional finite element method, and meteorological parameters are input into the model, so as to obtain the power generation, hydrogen production rate and the efficiency of converting solar energy, wind energy and electric energy into hydrogen energy under different capacity configurations of each part of the system. Using the model established in this paper, the parameters of wind and solar energy resources, environmental factors and load power in different regions are input. By changing the battery capacity, observing the battery operation and DC bus output, the battery equipment suitable for the whole system can be selected.
Capacity Optimization and Maintenance of Low Voltage Reactive Power Compensation Equipment in Distribution Netw
Authors: Liu Yunsong , Chen Xiaolei , Hu Weihua
Published: August 2021

Low-voltage distribution network has the characteristics of large number of nodes and branches, radial network and three-phase asymmetry in normal operation, which directly affects the power quality of users. In this paper, the load variation, the three-phase asymmetry and the capacity attenuation of capacitors are considered, and the state evaluation and three-phase capacity planning of LV reactive power compensator are studied. Genetic algorithm is used to realize economical and efficient control effect of bus voltage stability through reasonable planning of finite compensation equipment in multi-node system. Experimental results show that the proposed method can effectively optimize the location and capacity of the compensation device, and can improve the overall voltage level of distribution network economically and reasonably.
Risk Assessment of Wind Swing Flashover of Transmission Lines Based on Matter-Element Extension Model
Authors: Yin Xiaobei , Xu Xianglian , He Yu
Published: August 2021

In extreme weather, the line trip-out events caused by the wind swing of the transmission line occur frequently, severely affecting the normal operation of the power system. Since the structure of the operating transmission line is difficult to be improved, wind swing flashover risk assessment is of great significance for the operating transmission lines. In this paper, a transmission line wind swing flashover risk assessment model based on the matter-element extension model is proposed. The analytic hierarchy process (AHP) and entropy weight method are applied to comprehensively calculate the weight value of the selected assessment index. This model can assess the early warning level of a certain tower unit in the transmission line. Finally, the feasibility and effectiveness of the proposed assessment model are verified by practical examples.
Study on 10kV Line Characteristics Based on Medium Voltage Carrier
Authors: Li Yongbin , Chen Wenjun , Yu Tao , Qi Minglu , Zhang Wang , Li Liang
Published: August 2021

Abatract

Using medium voltage carrier communication to achieve full coverage of power information acquisition and distribution automation has become a hot spot in the domestic power industry. The characteristics of 10kV line will largely affect the reliability of medium voltage carrier communication, but due to the influence of voltage level and other factors, the research on 10kV line characteristics is not mature. In this paper, a research method of 10kV line characteristics based on medium voltage carrier is proposed. The improved medium voltage carrier communication machine and coupler can realize the collection of 10kV line impedance, attenuation and noise, accumulate useful data for the long-term study of 10kV line characteristics, help to improve the reliability of medium voltage carrier wave communication and assist 10kV line fault monitoring.
Analysis of solar interference simulation test for flame detectors
Authors: Zhong Chen , Liu Shen , Shao Yu , Xu Xiaoxiao
Published: August 2021

The light interference is an important reason for the false alarm or blindness of the flame detectors, and the effect of sunlight interference is particularly significant. In order to meet the requirements for the evaluation of the anti-sunlight interference performance of the flame detector, it is necessary to classify the solar interference severity according to the light climate data. On this basis, the solar interference simulation equipment and test method with quantitative test are designed. Through tests under different seasons, times and light conditions, the reliability and effectiveness of the test equipment and test methods are verified, the measurement uncertainty is calculated. Test results provide technical support for the standardization of sunlight interference test.
Improved Car Following Model Based on Supervised Learning
Authors: Ren Jie
Published: August 2021

Based on the existing traffic trajectory data, this paper uses a suitable neural network to construct a car following model, and then analyzes and studies the driver's car following behavior. By comparing the case with the traditional GHR car-following model, it is concluded that the improved car-following model is better.
Research on the thermal performance of SAC-HVIW system under the influence of solar transmission and local radiant heater
Authors: Zhou Jiri , Yu Tao , Lei Bo , Zheng Jiacheng
Published: August 2021

Solar air collector (SAC ) combining with hollow ventilated interior wall (HVIW ) system is a new type of energy-saving and environmentally friendly heating system. In engineering applications, it will be affected by solar transmission and local radiant heat sources (external heat gain), but these factors have not been considered in previous studies. In this paper, the series connection of HVIW simplified heat exchange unit model is used to improve the original thermal network of the SAC-HVIW building, and experimental verification is carried out. Results show that the temperature deviation of the air cavity and the wall surface calculated by the model are all within 10%, which can be used for the external heat gain calculation of HVIW. Then, in order to research the influence of the intensity of external heat gain and the position of action on the thermal process of HVIW, seven cases of simulation calculation were designed. Results show that when the external heat gain is the same but the acting position is different, it has little effect on the minimum and fluctuation of the indoor air temperature (all within 0.1°C). However, the change of external heat gain has obvious influence on the minimum temperature. When the external heat gain of cases are 136W and 900W, the corresponding minimum temperature are about 0.5°C and 3.5°C higher than the cases of 82W, respectively.
Simulation of Axial Flow Left Ventricular Assist Device’s Control Algorithm Used to Assist Different Levels of Heart Failure Based on the Circuit Model
Authors: Wang Houfu , Zhang Yunpeng , Wu Xiangyu
Published: August 2021

Modelling blood circulation is difficult. Due to the similarity of blood circulation and circuit loop, a numerical model coupled with the cardiovascular system and the left ventricular assist device is used to study the control algorithm of left ventricular assist devices in this study. According to severity, heart failure can be divided into three levels, and is simulated by varying the time-varying capacitance. Most of the left ventricular assist devices adopt the control algorithm of constant speed, which can reduce the pulsation of aortic pressure, and it is especially obvious in level III heart failure. We compare the positive pulse mode and the constant speed mode, and the results show that the positive pulse could increase systolic blood pressure and reduce diastolic blood pressure, which is more in line with the human aortic pulsation, and is more suitable for patients with high level of heart failure.
An approach to the transformer core residual magnetism evaluation and demagnetization
Authors: Jiansheng Li
Published: August 2021

Aiming at the problem of transformer inrush current suppression, a method of transformer core residual magnetism evaluation and demagnetization is proposed. Firstly, by setting the amplitude and time of DC current, different transformer core residual magnetism states are obtained. Secondly, under different residual magnetism conditions, the high-voltage winding of the transformer is charged and discharged in the forward and reverse direction alternately. The current change data in the process is collected, and the correlation coefficient of the current data in the forward and reverse charging processes is calculated, which represents the transformer core residual magnetism states. Finally, the DC current with alternating change direction and gradually decreasing amplitude is applied at the high voltage winding to demagnetize, and the variation of residual magnetism is analyzed during the demagnetization process.
Analysis and Research on Power Systems Computer Aided Design for Yindong DC Transmission System
Authors: xiaoxiao Zhao , yuxin yun
Published: August 2021

The AC equivalent (Shandong power grid) model of inverter side is established by electromagnetic transient simulation method, and the real data of Yindong transmission frame of HVDC is set in PSCAD model. Shandong power grid has set up different centralized faults. Asymmetric circuit accident are the most serious among them. Based on this analysis, we come to the conclusion that the fault of Shandong electric power AC system has a greater impact on Yindong DC transmission system, which provides important guidance for the reliable operation of Yindong HVDC transmission model in the future. We think it has better theoretical reference value.
Research on Simulation Ideas of Relay Protection Device on Load Test Based on Virtual Reality Technology
Authors: Man Xiaoping , Duan Fengju , Piao Yongxin , Tian Rubing , Qiao Xuejing , Ji Xuanying , Liu Yu
Published: August 2021

Various problems may occur in the design and installation of transformer, busbar and line differential protection. Therefore, it is particularly important to carry out a load test when the corresponding protection is put into operation. This article introduces the research status of virtual reality technology and the necessity of load test, puts forward the load test methods and precautions, and proposes a simulation plan combining virtual reality technology and load test.
A Model-Driven Two-Degree-of-Freedom PID Controller with Manual/Automatic Switching Without Disturbance
Authors: Jian Yu , Lei Wei , Xingwang Zhao
Published: August 2021

The model-driven two-degree-of-freedom PID (MD-TDOF-PID) controller is an excellent controller with simple structure and easy parameter setting. However, the MD-TDOF-PID controller has a fatal disadvantage, which is disturbed in the manual/automatic switching in industrial control field applications. This paper designs a model-driven two-degree-of-freedom PID controller with no disturbance in manual/automatic switching. It has all the advantages of this controller and eliminates the shortcomings of disturbance in manual/automatic switching. The controller proved by simulation experiment that the control effect is better than the ordinary PID controller.
Power Plant Small-diameter Tube Phased Array Inspection Verification and Inspection Technology
Authors: Xin-ying LIU , Jun-long SU , Lei ZHANG , Xiao-yang SU
Published: August 2021

In this paper, the phased array inspection is carried out on the small diameter pipes with artificial groove defects and natural defects, and then the conventional ultrasonic inspection and the penetration inspection after cutting and dissection are carried out respectively. The ultrasonic phased array inspection results are compared with the conventional ultrasonic and compared with the results obtained from penetrant testing, the reliability of ultrasonic phased array testing technology in the application of small-diameter pipe testing is analyzed. Then, taking the detection of the small pipe socket of the high-temperature superheater header of Huadian Weifang Power Plant as an example, it is verified that the ultrasonic phased array detection is feasible in the detection of small diameter pipe welded joints. Finally, the ultrasonic phased array testing process and testing technology of power station boiler small-diameter pipes are summarized, and the development direction of phased array testing application in power plant equipment inspection is prospected.
Design of monitoring system for electric vehicle charging station based on LabVIEW and STM32
Authors: Liu Qian , Yan XiaoJin , Zhang LiPeng
Published: August 2021

Charging-station provides power supply for electric vehicles, which is a necessary and important energy supporting infrastructure for development and large scale commercialization operation of electric.For the current charging-station management is overly dependent on high-cost devices such as industrial computer, this paper develops a charger field test device, which adopts STM32 as the data exchange interface between the host computer and charger. The charge data is sent to PC through STM32, and the monitoring system development is designed by LABVIEW.This method optimizes the decoding of message content, overcomes the defect of over reliance on high cost components, and strengthenes the ability of bottom message collection, enhances the system intelligence.The communication is fast, reliable and has a good man-machine interface.
Time-domain coupling analysis of semi-submersible floating foundation with four buoys for offshore wind turbine and its mooring system
Authors: Rong Xueping , Dou Peilin , Chen Jianxin
Published: August 2021

Taking OC4 semi-submersible floating foundation design of offshore wind turbine as the research object, the mooring system of OC4 semi-submersible floating foundation with four buoys is designed according to its structural parameters. The calculation model is established by AQWA software to analyze the time domain coupling analysis results of the floating foundation and its mooring system under the action of wind, wave, and current to determine its mooring system. The results show that for the four buoy semi-submersible floating foundation, the catenary mooring system has more advantages in the positioning and motion control of the floating fan.
Research on differentiated quality control strategy of UHV converter transformer based on economic sensitivity analysis
Authors: Chen Yingcui , Xie Wangyuan , Yu Xinru , Wu Chao
Published: August 2021

±800kV converter transformer is the most difficult and valuable equipment in UHVDC converter station. The total price of converter transformer in a single project is up to RMB 4.9 billion. The converter transformer connects the AC power grid and the converter valve hall, which is the hub of DC transmission. It realizes the electrical isolation, power exchange, voltage matching and on load regulation of AC / DC system through electromagnetic induction. The cost and quality performance of UHV converter transformer also determine the economy and reliability of power system operation. The purpose of this paper is to ± Taking 800 kV converter transformer as the research object, through a large number of investigation and field investigation, the establishment of the ± Procurement cost estimation model of 800 kV converter transformer. In this study, through exploring the cost characteristics and quality characteristics of the main materials and components of the transformer, the concepts of cost sensitivity and quality sensitivity are proposed, and the four quadrant matrix analysis method is used to analyse the cost and quality control of the transformer, and then the differentiated quality control strategy is formulated. It can guide the quality grading control of converter transformer in engineering, and realize the collaborative improvement of power equipment economy and reliability.
An Automatic Stripping Device for Hot-line Connection of 10 kV Cables
Authors: Han Wu
Published: August 2021

Electricity is an energy that is closely related to people’s daily life, and hot-line connection is often necessary in grid transformation and overhaul. Traditional stripping devices need to be operated manually with tools, which are not only time-and labor-consuming, but also have certain potential safety hazards. In this paper, a special stripping tool that is suitable for 10 kV high-voltage hot-line work is researched and designed based on summary of existing manual stripping devices. This new device is featured by a simple structure, safety, reliability, low operation risk, high efficiency, and a high automation level.
Study on coordination control methods of VPP
Authors: Song Xinxin , Wang Shitao , Shan Chunhong
Published: August 2021

China has become the world's largest energy producer, so we must speed up the construction of a clean, low-carbon, safe and efficient energy system. The large-scale access of renewable energy has an impact on the safe and stable operation of power grid, which makes it unable to directly join the power market operation. The coordination control objects of virtual power plant (VPP) mainly include various DERs, energy storage system, controllable loads as well as electric vehicles. The coordination control methods are mainly divided into centralized control, centralized decentralized control and completely decentralized control. In China, the demonstration project of VPP operation has been carried out in State Grid Jibei and Shanghai Electric power company.
Automatic Detection of Transmission Line Dangerous Points Based on Point Cloud Tower Section Classification Mode
Authors: Xing Long , Jian Zhao , Di Wang , Yuran Chen , Dandan Liu , Shaohua Wu
Published: August 2021

In the actual laser power inspection data processing process, the classification error of point cloud is inevitable. Some classification errors often need to be located with the help of dangerous points which is detected by mistake. Therefore, in the process of laser power inspection point cloud data processing, the detection of Dangerous points often needs multiple calculations. However, the dangerous point detection is often based on the whole line, and involves the data calculation of hundreds of tower section at the same time. The data magnitude is large and the calculation speed is slow, which seriously affects the efficiency of point cloud category correction. Aiming at the above problems, this paper divides the point cloud into tower segments, transforms the calculation unit of dangerous point detection from a whole line to a single tower segment, and records the modification of the point category in the tower segment. In the process of correcting the classification error and repeatedly calculating the dangerous points, only the tower segment with the modified category is recalculated. The practical application shows that this method can effectively speed up the data processing efficiency of laser power inspection.
Research on Visual Management system of Power Transmission Line based on two-dimensional GIS
Authors: Shaohua Wu , Jian Pan , Rong Yu , Jian Zhao , Yuran Chen , Di Wang , Wei Hu , Xin Long
Published: August 2021

In view of the imperfect construction of power transmission line visualization system, this paper studies the power transmission line visualization system based on open source GIS engine openlayers. At the same time, it makes full use of VUE, JavaScript front-end technology and express framework, Node.js, MariaDB, GeoServer and other server technologies to realize the two-dimensional GIS solution based on open source openlayers, which has a certain application value for two-dimensional GIS visualization management in the field of transmission lines. This scheme can meet the daily application needs of power grid transmission lines, and greatly facilitates the management of power grid transmission lines.
Hydraulic pump automatic test system based on C/S structure
Authors: Xu Linbing , Jin Xiajie , Xing Keli
Published: August 2021

In order to meet the automation production and testing needs of modern enterprises, this paper takes the hydraulic vane pump test bench as an example, and builds a set of hydraulic automatic measurement and control system based on C/S framework, which can meet the requirements of single/double pump test simultaneously. Among them, the client software is developed based on LabVIEW, the server is built based on FTP protocol and MYSQL database, and the test bench is successfully connected to the internal production management system of the enterprise through the local area network, realizing the integration of product model management, process control, automatic testing, result uploading and other functions. At the same time, the PID closed-loop control strategy was improved in the acceleration and loading stages to shorten the test time and reduce the system overshoot. Finally, the automatic run-in, efficiency verification and low-speed pressure-holding test of vane pump have been completed.
Optimal configuration of voltage sag monitors considering sensitive areas
Authors: Liu Haiyong , Dai Baihua , Zhu Hongfang
Published: August 2021

Voltage sags are unavoidable and cause serious harm to sensitive loads. Reasonable configuration of limited monitors can reduce monitoring costs and provide data support for sag management and reduction of sag hazards. Therefore, the optimal configuration of sag monitors is of great significance. Aiming at the traditional method that ignores the inconsistency of the degree of sag damage in different areas, an optimal configuration model of sag monitor considering the reliability of monitoring in sag sensitive areas and the location of phasor measurement unit (PMU) is proposed. The model takes sag observability as a constraint, takes the smallest number of monitors and covers the widest range of sag sensitive areas as the goal, and further configures PMU to assist in monitoring voltage sags. In addition, the Zeroin method is proposed to improve the accuracy of the exposed area calculation. The IEEE-30 system simulation shows that the proposed method can ensure the minimum number of monitor and high redundancy coverage of sensitive loads, ensuring its economic benefits. The proposed method overcomes the difficulty of balancing the monitoring cost with the monitoring capability of sensitive areas.
Study on safety management of guy wires in the construction of UHV (EHV) transmission lines
Authors: Jianjun Fang , Jiyong Hou , Chenghao Dai
Published: August 2021

The guy wires play an important and key role in the erection of the tower. Temporary guy wires are also used extensively in the stringing engineer. This study summarizes the causes of many serious accidents caused by temporary guy wires that do not meet the requirements of use and operation. It focuses on the high-risk links in the guy wire operation, from the calculation and verification before the use of the guy wire, the construction technical plan, the control of key links, and the construction process. The implementation of management and control is analyzed and summarized, and the key monitoring links of safety management and control of guy wires are summarized. The study provides reference for the construction of other similar HUV (EHV) high voltage transmission lines.
Evaluation of the Groundwater Safety and Analysis of the Spatial-Temporal Evolution in the Lower Plain of the Liaohe River, Northeast China based on the Improved DRASTIC Model
Authors: Bao Jianteng , Xi Xu , Zhang Yazhou , Ju Xueliang
Published: August 2021

The deterioration of the groundwater safety may lead to a series of ecological and social problems. In this study, we select relevant hydrogeological and anthropogenic parameters to construct the groundwater safety evaluation method for the lower plain of the Liaohe River based on the improved DRASTIC model. By spatially weighted overlay and Getis-Ord Gi* analysis of groundwater safety distribution maps, the main governance regions and main factors causing groundwater deterioration were identified. On this basis, the evolution trend of the groundwater key management area was quantitatively analyzed using the standard deviation ellipse (SDE) method. The results show that groundwater safety in the north and south of the lower plain of the Liaohe River are continuing to deteriorate. The correlation test between the groundwater safety index and the measured nitrogen concentration verified the scientific accuracy of the proposed groundwater safety evaluation method.
An Attention-based Recurrent Neural Network for Resource Usage Prediction in Cloud Data Center
Authors: Xi Huidan , Yan Cheng , Li Huixi , Xiao Yinhao
Published: August 2021

To manage the computing resources efficiency is crucial for the Cloud data centers (CDCs). By predicting the resource usages of certain virtual machine (VM), the workload could be balanced before the resource overusing occurs. In this paper, we propse an attention-based time series prediction model, which contains an encoder of input attention mechanism and a decoder of a temporal attention mechanism, to optimize the efficiency of could data center. Experiments on Alibaba CDC VM trace dataset demonstrates that our proposed methods can outperforms the classic LSTM method, especially when the resource usage data is lack of relationship.
A Multi-level Watermarking Algorithm for RasterGeographic Data Based on Watermark Information Segmentation Mechanism
Authors: Haojun Fu , Yunbo Kong , Xiao Li
Published: August 2021

This paper presents a multi-level digital watermarking algorithm suitable for raster geographic data. First, the new problems caused by the multi-level distribution of raster geographic data and its impact on watermark embedding/detection are analyzed; and then, a watermark information segmentation mechanism is designed, the multi-level watermark embedding strategy is established on this basis, thereby building the multi-level digital watermarking algorithm of raster geographic data based on the watermark segmentation mechanism with the traditional robust digital watermarking algorithm as the prototype; finally, the experimental comparison and analysis of the multi-level watermarking algorithm and the prototype algorithm are made. Results show that the proposed multi-level digital watermarking algorithm not only maintains the performance of the prototype algorithm, but also effectively solves new problems caused by the multi-level circulation of raster geographic data, such as multi-copyright protection and multi-user tracking, and has a high practical value.
Design of Building Heating System Based on Distributed Variable Frequency Pump
Authors: Yang Yuhua , Zhang Fan
Published: August 2021

With the continuous development and progress of society, people’s requirements for living conditions have gradually changed. They begin to pursue the comfort and personalization of the living environment, while also pay more and more attention to the problems of energy and environment. In order to build a suitable living environment, the implementation of central heating is bound to consume all kinds of resources. In the heating process, the efficient use and effective saving of energy has become an important measure for the heating industry to achieve the coordinated development of energy and environment. Taking the central heating as the research object and the secondary side distributed variable frequency pump heating transmission and distribution system as the goal, this paper studies the energy saving of the distributed variable frequency pump heating transmission and distribution system. This paper provides a design method of distributed variable frequency pump heating transmission and distribution system, in order to provide some basis for the design of distributed variable frequency pump heating transmission and distribution system in the future, and solve the problem of high energy consumption in the traditional central heating transmission and distribution system.
Prediction of PM2.5 concentration in Guangxi region, China based on MLR-ARIMA
Authors: Wei Pengzhi , Xie Shaofeng , Huang Liangke , Zhu Ge , Tang Youbing , Zhang Yabo
Published: August 2021

In recent years, the problem of atmospheric pollution has received more and more attention. Combining the concentration data of various air pollutants monitored by the air quality monitoring stations in Nanning, Guilin, and Baise in Guangxi province in 2017 and the precipitable water vapor (PWV) data obtained by sounding stations in the three cities, analyzed the changes of PM2.5 and PWV in major cities in Guangxi and build the multiple linear regression-differential autoregressive moving average (MLR-ARIMA) models respectively make short-term predictions for the changes in PM2.5 concentration in the three cities. Among them, the mean absolute error (MAE) of the prediction results of Nanning, Guilin and Baise are 7.57μg/m3, 12.75μg/m3 and 7.67μg/m3, compared with the multivariate linear regression model and the neural network model, the prediction accuracy of this model in Nanning is 43.55% and 46.50% higher than that of the multiple linear regression model and neural network model, respectively, and in Baise is 21.41% and 26.32% higher accordingly, The model prediction effect in Guilin is optimal for the neural network model, which improves 24.46% and 11.84% compared with MLR and MLR-ARIMA models, respectively, where MLR-ARIMA model still has 14.31% accuracy improvement compared with MLR model. This study has some reference value for PM2.5 prediction work in major cities in Guangxi, China.
Security Application of Encryption Technology in Network Communication
Authors: Jin Jin , Zhao Lipeng , Zhang Guoquan , Zhang Shenguo , Zhang Shengui
Published: August 2021

With the development and maturity of science and technology and the arrival of the Internet era, instant messaging software has become an indispensable communication method in people’s life due to its comprehensive functions, high performance and high stability. However, due to the open, interactive and global nature of the Internet, there are a series of security problems that cannot be ignored, such as information leakage and virus transmission. Information security is particularly important to us and directly affects whether our personal interests can be effectively protected. Therefore, strengthening information protection and avoiding information leakage are important issues that need to be solved urgently. This paper designs a system based on hybrid encryption by using symmetric encryption original AES and improved symmetric encryption AES to ensure the efficiency of people in the process of information transmission and communication.
The effect of climate factors on Antarctic Ice Sheet Changes from Radar Altimetry
Authors: Yang Quanming , Tang Yun
Published: August 2021

The Antarctic ice sheet change is one of the key factors affecting global climate change. The influence of climate factors obscures the understanding to elevation change of the ice sheet. Due to the lack of understanding of the quantitative relationship between climate events and elevation change of Antarctic ice sheet, we here combined climate factor data to quantify the impact of climate events on the elevation change of Antarctic ice sheet. A strong correlation between climate factors and elevation change of ice sheet was found. And the influence between them exists time delay in some extent. Meanwhile, the influence of climate factors in the Antarctic ice sheet change was separated from the ice sheet change based on the Independent Component Analysis (ICA) and multivariate linear regression model. The study also indicates that the influence of climate factors may be an important contribution for the accelerated decline of ice sheet elevation in the Amundsen Sea.
The research of artificial shoreline extraction based on airborne LIDAR data
Authors: Hua Li Wei , Bi Yao Lian , Hao Liu
Published: August 2021

Shoreline is closely related to the management and development of the ocean, people’s life, and national economic construction, Therefore, it is particularly important to accurately obtain the location of the shoreline. The existing Shoreline Extraction methods are based on image data, lidar data, or the integration of the two kinds of data. However, due to the characteristics of image data, the extracted shoreline is often fragmentary or there are areas where shoreline can not be extracted, and the type of shoreline is more, there is no unified, uniform algorithm. Therefore, this paper attempts to extract shoreline of man-made construction areas from airborne lidar data, and the algorithm is implemented with C + + and PCL. The experimental results show that the method can extract shorelines completely with high precision. Compared with the contour tracing method, the shoreline extracted by this method is smoother, and there is no local regional jump.
Remote sensing image dense target detection based on rotating frame
Authors: Wang Zhixin , Wan Shaojun , Ma Xiaoying
Published: August 2021

Detecting densely arranged and arbitrarily oriented targets on optical remote sensing images is a challenge, and there is much room for improvement in existing algorithms. In this paper, an end-to-end two-stage rotating target detection model based on rotating frames is proposed. This model adds FPN + PAN feature fusion structure after the backbone network to obtain enhanced features that fuse the feature information of each layer, and secondly, fine-grained rotation detection is accomplished by introducing Oriented Region Proposal Network and Oriented Region of Interest Pooling layer. By comparing the performance of this paper’s algorithm with the current mainstream rotation detection algorithm on DOTA remote sensing dataset, this paper’s algorithm can solve the difficult problem of detecting remote sensing targets with tight arrangement and arbitrary orientation to a certain extent.
Design and Improvement of Transmission Line Online Monitoring Communication Network
Authors: Peng Taiwei , Tian Feng , Lv Jiang , Sun Yanzhi , Cui Chen
Published: August 2021

Absrtact: transmission line is an important part of smart grid construction, which has many factors, such as wide distribution, long distance, complex working environment, difficult maintenance and easy to be damaged by natural external forces, etc. Among them, the construction of transmission line online monitoring network plays an important role in ensuring the stability and safe operation of online monitoring technology. In this paper, through the analysis of the transmission line and on-line monitoring transmission data demand and the existing problems of the current communication network, the communication network and data transmission system for transmission line monitoring is designed, which provides some reference for the construction of stable operation of the transmission line on-line monitoring network.
Analysis and Practice of Detection Methods for Goafs in Complex Coal Mines
Authors: Li Xueliang , Wang Jinpeng , Guo Xiaoli
Published: August 2021

The structure of the coal mine goaf is complex and its stability is easily affected by many factors. The use of reasonable detection methods to obtain basic data on the development characteristics of the overburden cavities, cracks and separations in the goaf is very important for the development and construction of the goaf. Meaning. The article summarizes and analyzes the currently commonly used goaf detection methods, and compares their applicability and advantages and disadvantages. Finally, the combination of engineering examples verifies the use of drilling core, drilling TV camera technology, and geophysical logging. The method provides a certain reference for the design and construction of the goaf detection project for the reliability of the goaf detection.
Research of Airfoil Optimization Based on CST Method and Genetic Algorithm
Authors: Zhang Jing , Chen Chang , Si Wenjie , Chai Xudong , Hong Yan , Yang Xueqi , Wang Yanning
Published: August 2021

Aiming at the aerodynamic optimization problem of guided ammunition airfoil, genetic algorithm is used to optimize the lift-drag ratio of the airfoil based CST geometric description method with given inflow velocity and fixed angle of attack. Firstly, the parameter space generated by CST parameterized airfoil description method is performed with binary code and the basic operations of genetic algorithm such as selection, crossover and mutation. Then, the external CFD solver is called to automatically divide the grid and calculate the lift-drag ratio through the control script. Finally, the target solution is obtained by searching. The calculation results show that this method can obtain a optimal target solution in relative less generation for a group of airfoils generated randomly in a certain search space.
Influence Analysis of Strong Wind on the Performance of Deep Space Large Aperture Antenna
Authors: Xiaofei Xu , Zongqing Wu , Wei Chen , Li Qiang
Published: August 2021

With the continuous increase of the deep space detection range, the establishment of the space-to-earth link and the stable transmission of the signal are the main problems facing. Increasing the antenna aperture of the ground-based measurement and control equipment can effectively improve the signal receiving sensitivity. However, the increase in antenna size brings about an increase in wind resistance. Strong wind will cause resistance to the driving of large-aperture antennas in deep space and cause certain deformations in the structure. This article takes a 35-meter-aperture antenna as an example, aiming at the antenna being orthogonal and parallel to the wind direction, the simulation analysis was performed under the influence of strong wind in the two cases, and the deformation cloud image of the antenna mouth surface was obtained. The antenna gain loss caused by the deformation error of the main surface and the translation of the secondary reflection surface was calculated, and the maximum gain loss reached 3.70dB.
Evaporation of R32/R1234yf Mixture on the Wall: A Molecular Dynamics Study
Authors: Xia Di , Shen Hongtao , Xiong Jianjun , Han Guodong
Published: August 2021

The mixed refrigerants have a great potential in the energy industry, while the micro-mechanism of evaporation of mixed refrigerants is still unclear. Therefore, molecular dynamics simulations were employed to investigate the evaporation of the R32, R1234yf and their mixture on the Pt surface at 230 K, 250 K and 350 K, respectively. The results indicate that the presence of R1234yf will suppress the evaporation of R32. The adsorption interaction between R32 and substrate is lower than that of R1234yf. The film boiling is found at high temperature evaporation. Meanwhile, the heat flux of the system decreases due to the heat transfer deterioration.
Research review on the Key Technology of Preventive Maintenance: The Durability of 4.75mm NMAS Stone Mastic Asphalt (SMA-5) Ultra-thin Overlay
Authors: Liu Jingxian , Wei Shucai , Ling Yuwei , Tai Jiahao , Shao Chenfeng , Zhu Siyue
Published: August 2021

SMA-5 Ultra-thin Overlay is a kind of preventive maintenance material which has the advantages of fast construction, good surface texture depth, cost-effective and environmentally friendly. It is also suitable for the maintenance of bridge and tunnel which have restriction on elevation. However, the insufficient durability is the key factor which restricts the development of SMA-5. This article summarizes the key technology to enhance the durability of SMA-5 in terms of its material composition, grading and mixture design methods, which provide a reference for improving the durability of SMA-5 and promoting the application of SMA-5.
Dynamic response of hollow sandwich cement rod of 110 Kv transmission line
Authors: Xingeng Li , Bichuan Fu , Yuheng Ouyang
Published: August 2021

Taking a 110 kV transmission line as the research object, a refined finite element model of three pole two line transmission tower line system is established.Considering collision and contact between a dropped wire and ground, nonlinear dynamic analyses of the system with different break points and different numbers of broken wires were performed. The results showed that the break point location has little effects on the impact action of broken wire; the tension decay coefficient of the broken wire decreases with increase in the height of the hanging point position, while that of the unbroken wire decreases first and then increases with increase in the height of the hanging point position. The initial pretension, wind direction angle and span of the cable are selected for parameter analysis. The influence of these parameters on the nonlinear dynamic stability critical load of the hollow mezzanine concrete pole line system is investigated.
Study on polyester fabric grafted with acrylic acid initiated by ultraviolet light
Authors: Xin-Cheng Xie , Xiao-Jing Yi , Wen Huang , Zuo-Shen Li , Xin-Long Ling
Published: August 2021

Polyester fabric has compact molecular chain structure, high crystallinity, no hydrophilic groups except hydroxyl groups at both ends, and poor hygroscopicity. The surface of polyester fabric was modified with acrylic acid by ultraviolet light in order to improve its hydrophilicity. The best technological conditions are as follows: the concentration of acrylic acid is 10%, the irradiation time is 1 hour, and the concentration of photoinitiator is 5%. Under the optimum conditions, acrylic acid is successfully grafted onto the surface of polyester fabric. There are grafting polymer between the fiber gaps or on the surface of fiber, accompanied by cross-linking or bonding. The hydrophilicity and dyeing rate of modified polyester fabric are improved obviously. The breaking strength and elongation at break of treated polyester fabric increases and decreases, respectively.
Functionalized α-GDY with different displacement distance for CO2/CH4 diffusion and separation
Authors: Sainan Zhou , Huili Xin , Wanru Zhai , Shengyu Xu , Sen Liu , Hao Dong , Xiaoqing Lu
Published: August 2021

Functionalized α-GDY with – H, – F, and – N for different displacement distance were designed as promising membranes for separation CO2 from CH4 by using molecular dynamics simulations. The α-GDY were regulated to form suitable pore sizes by functionalization and displacement for separation CO2 from CH4. F-GDY membranes and displacement distance with 1/3 have ultralow CO2 selectivity over N2 of ~0, which indicate that no CO2 pass through F-GDY membranes and CO2 and CH4 were separated efficiently. Among these membranes, N-GDY with 1/3 displacement distance has highest permeance of 5.97 × 10-5 mol m-2 s-1 Pa-1 at 300 K. Relative concentrations distribution confirmed that almost CO2 molecules adsorbed the pore wall of membrane, CH4 distributed in the gas box and vacuum. The interaction energy between gas molecules and membrane was analyzed to elucidate the significant impact of functionalization on the selectivity of CO2 over CH4 and CH4 permeances passing through porous BN membranes.
Research progress in damage assessment methods for tight sandstone gas reservoirs
Authors: Zhou Guangxu , Ye Yan , Zhou Fujian
Published: August 2021

In the process of oil and gas development, the perfect reservoir damage evaluation method is an important condition to realize the economical and efficient development of the reservoir. At present, great progress has been made in the exploration of tight oil and gas. However, due to the characteristics of low porosity, low permeability and low water saturation of tight sandstone gas reservoirs, conventional reservoir damage evaluation methods are not applicable to it, and no systematic evaluation method has been formed yet. The damage evaluation methods of tight sandstone gas reservoirs mainly include the steady-state method and the unsteady-state method. The steady-state method is mainly the high temperature and high back pressure method, while the unsteady-state methods are the pressure attenuation method and the pressure transmission method which are widely applicable. Visualization technology, microfluidic technology, flow rate evaluation method and recovery evaluation method are the new methods to evaluate reservoir damage, which are in the further research. This paper summarizes the research progress of reservoir damage evaluation methods for tight sandstone gas reservoirs, analyzes the main evaluation methods, experimental equipment and improvement measures, and points out the problems that need to be paid attention to and solved, in order to provide reference for efficient and accurate evaluation of reservoir damage in tight sandstone gas reservoirs.