bluuebunny/crossref_metadata_2025 huggingface dataset:
Facilitating student involvement in physics learning through worksheets assisted by augmented reality during the covid-19 pandemic: Analysis of teacher perceptions
Authors: Agustiana L , Abdurrahman A , Andra D , Widyanti R , Zahara M
Published: March 2021

One of the obstacles faced in physics learning during the COYID-19 pandemic is the low students’ involvement in the learning activities. This research was aimed to describe the views of Islamic school physics teachers on the importance of. Augmented Reality-assisted worksheet teaching materials in facilitating students’ involvement in the learning process This research involved 31 Islamic high school physics teachers in Lampung Province. Indonesia. The explanatory design mixed methods were used in this research. The results showed that the Augmented Reality-assisted worksheet could increase potentially student involvement in physics learning diuing the pandemic by implementing a learning management system smted to students’ learning needs and facilities. The results of this research also illustrated the importance of designing worksheets that support the effectiveness of online learning during the COYID-19 pandemic.
Investigation of the relationship between skin-emitted volatile fatty acids and skin surface acidity in healthy participants—a pilot study
Authors: Shetewi Tasneem , Finnegan Melissa , Fitzgerald Shane , Xu Shuai , Duffy Emer , Morrin Aoife
Published: March 2021

Volatile organic compounds (VOCs) emitted from human skin are of great interest in general in research fields including disease diagnostics and comprise various compound classes including acids, alcohols, ketones and aldehydes. The objective of this research is to investigate the volatile fatty acid (VFA) emission as recovered from healthy participant skin VOC samples and to characterise its association with skin surface acidity. VOC sampling was performed via headspace-solid phase microextraction with analysis via gas chromatography-mass spectrometry. Several VFAs were recovered from participants, grouped based on gender and site (female forehead, female forearm, male forearm). Saturated VFAs (C9, C12, C14, C15, C16) and the unsaturated VFA C16:1 (recovered only from the female forehead) were considered for this study. VFA compositions and abundances are discussed in the context of body site and corresponding gland type and distribution, and their quantitative association with skin acidity investigated. Normalised chromatographic peak areas of the recovered VFAs were found to linearly correlate with hydrogen ion concentration measured at each of the different sites considered and is the first report to our knowledge to demonstrate such an association. Our observations are explained in terms of the free fatty acid content at the skin surface which is well-established as being a major contributor to skin surface acidity. Furthermore, it is interesting to consider that these VFA emissions from skin, governed by equilibrium vapour pressures exhibited at the skin surface, will be dependent on skin pH. It is proposed that these pH-modulated equilibrium vapour pressures of the acids could be resulting in an enhanced VFA emission sensitivity with respect to skin surface pH. To translate our observations made here for future wearable biodiagnostic applications, the measurement of skin surface pH based on the volatile emission was demonstrated using a pH indicator dye in the form of a planar colorimetric sensor, which was incorporated into a wearable platform and worn above the palm surface. As acidic skin surface pH is required for optimal skin barrier function and cutaneous antimicrobial defence, it is envisaged that these colorimetric volatile acid sensors could be deployed in robust wearable formats for monitoring health and disease applications in the future.
Analysis on the Development Prospect of small and medium-sized pumped Storage Power stations in East China
Authors: Xu Lingjun , Liu Zhihua , Zheng Shuqing , Wan Jingying
Published: March 2021

Small and medium-sized pumped storage power stations have the advantages of short construction period, fast action, relatively low requirements for topography, relatively easy location, relatively low investment, easy layout in load center, flexible operation and fast start-up speed. They can cooperate with the operation of small hydropower, wind power and photovoltaic power to alleviate the grid connection problems caused by the randomness, intermittence and volatility of output. They can improve the landscape absorption capacity of East China Power Grid and promote the development of renewable energy. They can also better meet the needs of regional operation of the power grid, connect to the 110kV or 220kV power grid nearby, save 500kV line corridors and investment, improve the guarantee rate of power supply in local areas, reduce power outages, power limits and power generation can not be delivered and other problems. As an important tool to achieve energy conservation and emission reduction, they can promote the development of low-carbon economy and meet the requirements of energy storage technology and industrial development in China.
Research on benefit evaluation method of pumped storage power station
Authors: Xie Mingjie , Gong Chuanzheng , Chen Tongfa , Pan Ligang , Wang Qingran , Zhang Kailin , Chu Hongchen , Yang Kai
Published: March 2021

The development of pumped storage power stations in China is relatively short, and there is a lack of objective evaluation of the system benefits of pumped storage power stations, which leads to the problems of inaccurate functional positioning, single investment mode, and imperfect electricity price mechanism of pumped storage power stations in China, hindering the healthy development of pumped storage power stations. In order to solve this problem, this paper establishes the benefit evaluation system of pumped storage power station, selects economic benefit, technical benefit, social benefit and environmental benefit as evaluation indexes, and constructs the benefit evaluation model based on order relation analysis and entropy weight method.
Influence of coupling agent on the Bound rubber and Dynamic Properties of aluminum sodium silicates filled HNBR composites
Authors: Bi Weina , Guangshui Yu , Sun Jujie , Goegelein Christoph , Hoch Martin , Kirchhoff Joerg , Zhao Shugao
Published: March 2021

Hydrogenated acrylonitrile-butadiene rubber (HNBR) was used as polymer matrix and micrometer aluminum sodium silicate mineral filler was used as dispersed phase to prepare silicate mineral / polymer composites. Different Triethoxy silane coupling agents were chosen to modify sodium silicate, the vulcanization properties, physical mechanical properties and dynamic mechanical properties of silicate / polymer composites were studied. The results showed that the addition of silane improved the dispersity of sodium aluminum silicate effectively in hydrogenated nitrile rubber. Although the mechanism of actions between VTEO,GLYEO,AMEO silanes and rubber was different, the interactions between filler and rubber were enhanced. These three kinds of triethoxy silane improved the physical and mechanical properties of sodium aluminosilicate / hydrogenated butyronitrile composites obviously.
Research on Security Verification Mechanism of Perception Layer Terminal of Power Internet of Things Based on Device Operation Fingerprint
Authors: Liu Siyao , Yu Ye , Guo Anle , Zhao ZhongYing , Wu ZongHou , Zhou Yi
Published: March 2021

Integrating the Internet of things technology into the power grid is a major development trend in the future, which can effectively improve the overall performance of the existing power grid. However, due to the traditional Internet of things mainly uses the form of digital password for security protection, due to the low security problems, there are great hidden dangers to the operation of the equipment. For this reason, this paper proposes a security verification mechanism for the perception layer terminal of the power Internet of things based on the device operation fingerprint. In this paper, the biometric fingerprint identification technology and Internet of things architecture are deeply studied, and the fingerprint identification algorithm process and steps are analyzed in detail, and the processing time of each step is compared. In order to improve the comprehensive performance of the security verification of the perception layer terminal of the Internet of things, according to the actual security requirements of the power Internet of things, combined with the biometric fingerprint identification technology, a new security verification system is established. In this paper, the security mechanism of RFID system is adopted, and the performance of fingerprint image filtering is improved by optimizing calculation method and simplifying algorithm. By improving the identity authentication mode and optimizing the data encryption transmission mechanism, the security protection performance of the perception layer of the power Internet of things is further improved. In the simulation test, the system identification accuracy rate of this paper reaches 99.75%, and the software implementation efficiency test results are good, which shows that the system in this paper has high security protection performance, and can meet the current security protection needs of the power Internet of things.
Research on the Innovation System of University Production and Education Integration Based on Computer Big Data
Authors: Gao Zhanwang , Wu Bei
Published: March 2021

The advent of the “Internet +" era has changed the traditional model of computer education. In the field of education, with the help of the rapid development of mobile-related technologies, the mobile teaching mode combined with university curriculum teaching is growing into an increasingly popular teaching method. This article first analyzes the significance of the Internet + industry-education integration innovation education reform, the current research status at home and abroad, and introduces the specific research content and reform goals in detail. The research is based on the integration of industry and education in the “Internet +" era. The reform of the innovative education model proposes to integrate production and education into innovative education throughout the entire process of talent training. At the same time, the thesis designs and implements a multi-Agent-based innovation management information system for the integration of production and education in colleges and universities. The system has intelligent functional modules such as talent management, asset management, and system management. Each functional module of the system is introduced in detail and put forward the problems that should be paid attention to in the system implementation process.
Design of high precision transient waveform measurement algorithm based on oversampling and mean filtering
Authors: Gu Shuang , Ren Xiaoming , Li Dengpan
Published: March 2021

In the transient impulse test of simulated lightning, the accuracy and reliability of digital impulse measurement secondary system has always been a research hotspot in industry and academia. In this paper, an oversampling mean filtering algorithm is proposed to overcome the disadvantages of high-resolution ADC and low-resolution ADC which are greatly affected by quantization noise in the secondary system of impact test measurement. By increasing the sampling frequency and mean filtering, this method can achieve the accuracy index that can only be obtained by expensive high-resolution chip using cheap low-resolution chip, and it is easy to implement. In this paper, the principle of the algorithm is analyzed in detail, and its implementation is described. On this basis, the performance of the algorithm is discussed through simulation analysis, and the effectiveness of the algorithm is verified through experiments.
Simulation Research on Transformer Pre-test High Voltage Electrical Insulation Parameters
Authors: Xu Minhu , Guo Yun , Zhang Kexin , Zhang Hang , Shen Yubo , Zhao Xiangyu
Published: March 2021

This article uses an image processing method to study the hydrophobicity of transformer composite insulators, and then determine the surface aging performance of transformer composite insulators. In order to meet the requirements of the randomness and ambiguity of the hydrophobic image, this paper uses a series of algorithms to process the hydrophobic image of the composite insulator: the enhancement of the hydrophobic image based on adaptive histogram equalization, the hydrophobic image based on wavelet transform Filtering and segmentation of the hydrophobic grade classification of composite insulators. Taking characteristic parameters such as the largest water droplet shape factor and area ratio as input, and the surface insulation aging performance of composite insulators as output, the relationship between insulation parameters and insulation aging performance is established. The simulation results show that the method can judge the surface insulation aging performance of composite insulators into three states: good, normal, and bad. Especially when the maximum water drop area ratio is input, the classification accuracy rate reaches 933%.
Research on High Voltage Insulation Performance of Grounding Grid in Large Substation
Authors: Zhang Jian , Guo Yun , Xu Minhu , Zhang Rui , Shen Yubo , Zhang Kexin
Published: March 2021

The gap between overhead ground wire insulators is changed by external force or subjected to overvoltage, intermittent breakdown will occur, and continuous arcing will occur in severe cases. Real-time monitoring of the current change on the ground wire is of significance to the reliable operation of the overhead ground wire major. The article proposes a method to detect the surface contamination of composite insulators by measuring the ground current of the insulator. The ground current characteristics of composite insulators are studied, and the test loops of composite insulator ground current, body leakage current and surface leakage current are established respectively. The above three currents of the insulator were measured and compared and analysed. At the same time, the article focuses on the design and development of the hardware system of the DC grounding system insulation resistance tester with digital display and multi-channel inspection function based on the microcontroller.
The design of hardware firewall based on Acorn RISC Machine
Authors: Li Yunzhe , Zhang Xingfu , Jia Bowen
Published: March 2021

This article implements a high-performance and low-cost ARM firewall, whi ch can guard computers under public network conditions and make public information more secure in today’s information age. The designed firewall operates at the network l ayer to monitor the normal communication between the internal LAN and the external Internet, while resisting external network intrusions. The firewall can be configured to control whether internal hosts can access the Internet. When malicious Internet intrusio n is detected, the firewall prevents data packets from flowing into the intranet.
STM32-Based Contactless Temperature Measurement and Identification Device
Authors: Xia Weiran , Yan Jiantao , Li Yunzhe
Published: March 2021

In recent months, in the epidemic prevention and control in the early stages of the war, the shortage of emergency supplies, supply shortages, global procurement of basic products cannot meet demand and other issues are still fresh in people’s minds. At the same time also let a once unknown ordinary product is a great success, which is non-contact infrared thermometer, also commonly known as handheld ear and forehead temperature gun, he plays an irreplaceable important role in the epidemic prevention and control, and if the temperature can be measured at the same time, the use of deep learning to identify and record the identity, then the promotion of the thermometer will be more successful.
An Empirical Study on the factors affecting the Student’s Willingness to Use of Mobile Social E-commerce Based on UTAUT 2
Authors: Huang Nan , Wu Haifan , Han Linlin
Published: March 2021

With the rapid development of e-commerce, mobile social e-commerce has been accepted by consumers. College students are the main components of netizens. This study integrates the variables of perceived trust and perceived risk based on the UTAUT2 model, and constructs an influencing factors research model on student users’ willingness to use mobile social e-commerce. Moreover, an empirical analysis is conducted aiming at the sample data obtained by users in colleges and universities. SPSS24.0 is used to accomplish the analysis of the descriptive statistical, AMOS24.0 is used to conduct the structural equation model verification. In the study, it is found that the willingness for college student to use mobile social e-commerce is positively affected by perceived trust and negative influence by perceived risk. The hedonic motive affects college student’s willingness to use mobile social e-commerce through influencing the perceived trust and the performance expectation.
Fabrication of Ceramic Nanofibers by Electrospinning
Authors: Teng Yu , Liu Jie , Li Yuexiwei , Qiu Linling , Zhang Wenli , Zhang Jinliang
Published: March 2021

Ceramic nanofibers made by electrospining shows different functions and can be widely used as filtration, biomaterial devices, sensing, catalytic supports and chemical decomposition materials. There are many fabrication methods to obtain ceramic nanofibers. In this paper, ceramic nanofibers with high performance thouth two main synthesis methods are reviewed.
Investigation on control in oxide scale formation and prevention of peeling off in ultra-supercritical unit
Authors: Zhang Tianyu , Zhang Xin , Shi Xiufeng , Zhao Zhenning
Published: March 2021

It is a common problem that oxide scale of boiler tube peels off in supercritic al unit. In recent years, many boiler tube burst accidents have been caused by oxide sc ale peeling off and blocking. Therefore, the analysis and research of oxide scale is of g reat significance. In order to control the occurrence of such accidents and reduce the ec onomic losses of thermal power plants, this paper mainly analyzes the factors influenci ng the oxide scale growth rate, peeling off condition and puts forward corresponding p revention and treatment measures.
The design and optimization of concentrating solar system in Wuhan based on clear sky model
Authors: Mao Qianjun , Yang Yizhi , Li Tao
Published: March 2021

To slow down fossil energy usage and protect the environment, concentrating solar power has experienced tremendous growth. This paper focused on the relationship between annual solar irradiation and tilt angle of the concentrating system to find the optimal tilt angle when annual solar irradiation is maximum. In the calculating process, the tilt angle between 0° and 90° is separated from several angles with a 5° interval and calculate the corresponding annual solar irradiation. A relationship line between solar irradiation and tilt angle is indicated, and the optimal tilt angle is discovered. The relationship between solar irradiation and tilt angle in different seasons is also investigated. The result of this paper would be a theoretical foundation to promote the application of concentrating solar systems in Wuhan.
Investigating Teachers’ Questioning in Second Language Acquisition Based on SETT Framework
Authors: Chen Zhixian
Published: March 2021

This paper focuses on teachers’ use of questioning with regard to the enhancement of students’ learning opportunities in Second Language Acquisition (SLA). The source of analysis comes from a classroom in China adopting curriculum of English as a Second Language (ESL), and the research is mainly based on the SETT (Self-Evaluation of Teacher Talk) framework. Through a case study on extracts taken from the classroom with different learning modes and contexts, understanding can be deepened about how varied questions are used to facilitate learning opportunities and improve learning outcomes by achieving certain pedagogical goals and activating different interactional features in the classroom, promoting second language acquisition more effectively. In short, this investigation aims at viewing questioning in an L2 (second-language) classroom with theoretical support in order to provide a reference for more studies on educational practice and second language learning.
Interpersonal Significance Analysis of Alberto Fernández’s Speech Against Epidemic Situation
Authors: Zhao Yuanyuan
Published: March 2021

Based on the interpersonal function of Systemic Functional Grammar (SFG), this paper builds Fernandez Speech Corpus for Anti-epidemic, and analyzes the interpersonal meaning of the speech delivered by the current Argentine President Alberto Fernández during the COVID-19 epidemic in two aspects-mood and modality. Therefore, the way of Alberto Fernández’s speech through interpersonal meaning during the anti-epidemic period was explored.
Study on Microstructure and Fatigue Properties of Q960 High Strength Steel
Authors: Zhu Pengxiao , Wen Jun , Li Yi , Zhang Dongya , Ma Xuejiao
Published: March 2021

The microstructure and fatigue properties of Q960 high strength steel were studied by optical microscope, conventional mechanical properties and fatigue tests. The results showed that the microstructure of Q960 high strength steel was tempered sorbite, the grain size grade 9, and the internal inclusions A1 and B1.5. The brinell hardness of Q960 high strength steel was 326.5HBW10/3000, the tensile strength more than 1000MPa, the impact energy 86.5J, which indicated good strength and toughness. In the case of high fatigue strength, the dispersion of fatigue life was low. The dispersion of fatigue life increased with the decrease of fatigue strength.
Prediction of the Optimal Umbrella Shape of Insulators Based on Data Mining Technology
Authors: Xing Xiangrong
Published: March 2021

The insulator flashover process is affected by many factors. In order to better study the factors that affect the insulator flashover voltage, and then accurately predict the insulator flashover voltage. In this paper, 11 different types of composite insulators are studied through artificial pollution tests. Data mining technology has been widely used now. In order to better apply data mining in the prediction of insulation flashover voltage, this paper adopts the BP neural network in data mining technology to predict the flashover voltage of different umbrella-shaped insulators. In addition, in order to further improve the prediction accuracy of the model, this paper uses the global search capability of genetic algorithm to optimize the initial weights and thresholds of the BP neural network, and optimizes the BP neural network prediction model, and established an optimization model based on genetic algorithm to optimize BP neural network. Through this method, the flashover voltage of the insulator can be predicted in time, which is of great significance for maintaining the safe and stable operation of the power system.
Determination of Interfacial Heat Transfer Coefficient of 22mnb5 Boron Steel in Hot Forming Based on Inverse Heat Transfer Method
Authors: Xiao Gang , Zan Zhiwei
Published: March 2021

The heat transfer coefficient at the blank-die interface is difficult to determine the values from experiments due to the influence of various factors, such as forming load, coating material, coating thickness, roughness of surfaces and gap formation caused by the deformation of blank and die, etc. In the present paper, the interfacial heat transfer coefficient (IHTC) between the blank and die is identified by using the method of inverse analysis based on measured temperatures. The results show that the method of inverse analysis is a feasible and effective tool for determination of the blank-die IHTC. In addition, it is found that the identified IHTC varies with temperature and load during hot stamping. The characteristics of the IHTC variation have also been discussed.
F-POWER Prosthetic Research on Flexible Receptacle
Authors: Lv Shaowei , Zhang Zhiyong , Xu Yanhua
Published: March 2021

In recent years, with the development of robot technology, the application of robot structure with high speed, high precision and high load-to-weight ratio has attracted the attention of industry and aerospace. Due to the increase of the flexibility effect of joints and connecting rods during the movement, the structure is deformed, which reduces the accuracy of task execution. Compared with rigid mechanical arm, flexible mechanical arm has the characteristics of light structure, high ratio of load to dead weight, so it has lower energy consumption, larger operating space and high efficiency, and its response is fast and accurate, and it has many potential advantages, so it occupies a very important position in various application fields. F-POWER flexible prosthesis is a man-machine integrated mechanical device that can be worn by people. It can complete the combination of man and machine, control the mechanical arm by human behavior, and help the disabled to complete daily grasping tasks. It can combine the high load and high precision of the machine with the flexibility and intelligence of the human body. At the same time, using adaptive flexible materials can improve the comfort and stability of the prosthesis. The combination of flexible gripper and mechanical gripper can effectively meet the needs of people with disabilities and reduce the difficulty of operation.
Solar panel cleaning vehicle based on Konda effect
Authors: Zhang Wenbo , Wang Zehao , Zhu Lingfeng
Published: March 2021

In order to solve the problem of parking difficulties in urban residential areas, a small auxiliary parking device is proposed. Starting from solving the social pain points such as unreasonable parking space planning, residents’ random parking, and reducing parking difficulty, it achieves the effect of assisting parking space planning and reducing parking difficulty. The device mainly provides power through the motor, and drives the drum to realize binary control by controlling the steering wheel of the vehicle owner, that is, controlling the switching of the whole movement, and the switching of the front back and left right of the control device. By pressing the spring switch on the wheel, the front control motor drives the gear clutch device to complete the bidirectional switching from left and right movement to back and forth movement. Through the shear fork supporting mechanism and separate self-locking slide rail, the car is lifted and the parking device is driven away.
Research on Automatic Temperature Monitoring System of Belt Roller in Western Suburb
Authors: Qing Chen
Published: March 2021

Most coal mine conveying systems in China are transported by belts. Belt conveying system is very important for coal mine production. Bearing is one of the important components of belt conveyor. During the running of bearings, if the temperature rises, it will affect the normal transmission of belt conveyor. In this paper, the continuous on-line temperature monitoring and temperature display of roller bearings of belt conveyor in the western suburbs of Zhaozhuang Coal Industry are realized based on the existing headquarter system of the western rubber belt and the underground industrial ring network. When the monitoring data exceeds the limit or is abnormal, sound and light alarm will be sent out in time.
Experimental Study on Presplitting Blasting of Roof Cutting Along Goaf with Thick and Hard Roof Plate
Authors: Tang Jianquan , Liu Hongliang , Chen Anfa
Published: March 2021

In order to explore the reasonable blasting parameters of the gob-side entry retaining technology under the specific conditions of thick and hard roof, and realize successful roof cutting and safe roadway retaining, the thick and hard roof of the XV1306 working face in the first panel of Yixin Coal Mine is used as the research background. The drilling parameters of blasting are analyzed, which contains the depth of slitting, angle of slitting and spacing of blasting holes. And the influence of charge structure and charge amount on the effect of presplitting blasting was studied through underground blasting tests. The results show that when the blast hole depth is 10m, the drilling angle is 15°, and the blast hole spacing is 500 mm, with adopting the “2+3+4+4+3+2” method to the deep-hole charge structure, the top-cut crack rate is more than 90%. the penetration effect of top-cut crack is good, which can meet the needs of roof cutting for pressure relief and control of surrounding rock in roadway retaining.
Application of Key Technologies for Multi-Terminal Change of Frame-Double Core Tube Super High-Rise Building
Authors: Chen Xu , Li Shimin , Yu Ziqiang , Xu Jialin , Wang Lijian , Pei Yusheng , Zhang Wei , Jing Zhanxu , Min Liuliang , Wang Yaru , Zheng Hui
Published: March 2021

Frame-double-core tube structure is a structural form suitable for super high-rise buildings with long or irregular standard floor plan. In this paper, the structural arrangement and structural member size of the double core tube are determined through the analysis of structural indexes such as stiffness calculation and torsion effect under rare earthquake. At the same time, through the research of all-steel climbing frame and aluminum formwork under the condition of super high-rise height and structural change, the application of all-steel climbing frame and multi-end aluminum formwork with super high-rise height change are solved, which speeds up the construction progress, greatly reduces the safety and quality risks in the construction process of super high-rise buildings, and at the same time, reduces the material and labor costs to meet the development requirements of green construction.
Research on Evaluation Index System of Autonomous and Controllable Capability of Aerospace Test and Launch System
Authors: Hu Yunlong , Xie Weiqi , An Jingwei , Yao Jingbo , Ma Wei
Published: March 2021

In order to solve the potential risks of code opening, backdoors, logic bombs, etc. in the key components, operating systems, and software of various hardware and software equipment in the aerospace test and launch system, an evaluation and research on its autonomous controllability is conducted. This paper analyzes the current status of the evaluation of the autonomous controllability of the space test launch system, put forwards the construction method of the evaluation index system of autonomous and controllable capability and the principle of index extraction, and constructs the evaluation index system. Finally, a case study is carried out based on the improved AHP method. The analysis results show that the research is of great significance to the development of autonomous controllability of aerospace launches and enhancement of the autonomy and advancement of aerospace test launch technology.
Research on the Integration of Launch Vehicle Test and Fault Diagnosis
Authors: An Jingwei , Cheng Long , Xie Weiqi , Hu Yunlong
Published: March 2021

According to the current situation of launch vehicle testing and fault diagnosis being carried out independently and with a high degree of manual participation, a plan of organically combining rocket testing and fault diagnosis for an integrated overall design is proposed, which is conducive to improving system integration and shortening the test cycle. Based on the analysis of the existing technology, the author respectively proposed a process-driven automatic test technology and a fault diagnosis method with an extended expert system as the core and a combination of multiple fault diagnosis technologies, aiming at the two core technologies in the integrated solution –automatic testing and fault diagnosis.
Research on the contribution rate of vocational education to social and economic development
Authors: Song Mengjun , Zhang Liping , Feng Yongxin
Published: March 2021

This paper makes a quantitative research on the promotion of vocational education to social and economic development. Taking the population of a village in Tianjin as the research sample. This paper makes a quantitative design on the role of education in the social and economic development for the village in the next 10 years, and obtains that vocational education has a relatively obvious role in promoting the economic development of the village, which provides scientific data support for the future education mode of the village population. So as to provide effective theoretical suggestions for the economic development for the village, the whole Tianjin, even the whole nation.
Research on Multi-objective Optimization of Capacity Allocation for Marine Hybrid Energy Storage System
Authors: Wang Zecheng , Li Xin
Published: March 2021

The hybrid energy storage system’s allocation problem is a multi-target and multi-direction optimization problem. Single-objective allocation for the Marine Hybrid Energy Storage System (MHESS) cannot help the hybrid energy storage system unit give play to its optimal effect. A diesel-electric hybrid ship is used as the object. In this paper, a mathematical model of a hybrid energy storage device is established, and multi-objective optimization allocation is performed on the model based on the NSGA-II. Finally, the optimized model is applied to a ship, and eleven kinds of batteries and six supercapacitors are selected for simulation. The simulation results show the relationship between the objective functions.
A compound control strategy for LCL-based three phase four leg shunt active power filter
Authors: Tao Mao
Published: March 2021

Conventional single inductor filter which is applied to three-phase four-leg shunt active power filter hardly meet the requirements for high frequency harmonic suppression. LCL filter has advantage both in high dynamic response and high frequency harmonic suppression. Repetitive control can realize accurate tracking of multi-harmonics signal. However, the design of corrector for repetitive control is mostly complicated. This paper proposes a topology of three-phase four-leg shunt active power filter based on LCL filter and improve its stability through capacitive current feedback. Compound control strategy which includes PI control and repetitive control is adopted to improve the compensation effect of harmonic current. Corrector for repetitive control has simple structure and is easy to design. The conventional PI control and compound control are compared and analyzed in detail. Moreover, the difference of property between LCL filter and single inductor filter is compared and analyzed. Simulation results show the correctness and effectiveness of the designed LCL filter and the proposed compound control strategy. The proposed method provides a reference for making three-phase four-leg shunt active power filter more practical.
Analysis and Modification of Vibration Issue of Condensate Regulating Valve in a Nuclear Power Plant
Authors: Zhang Yutao , Yan Dong , Dong Wenhui
Published: March 2021

Regulating valves are widely used in nuclear power plants. The critical application of regulating valves determines whether the unit and system can operate safely, stably and economically. Taking the analysis and modification of the vibration issue of the conventional island condensate regulating valve in a pressurized water nuclear power plant as an example, this paper expounds the essence of the vibration issue of the regulating valve and provides reference for other power plants to deal with the same issue..
Evaluation, Risk and Prospect for Electricity Investment in Five South American Countries
Authors: Liu Yuxi , Feng Yiming , Jiang Hongli , Li Yuxi , Zhou Baozhong
Published: March 2021

South America is the natural extension of the “One Belt, One Road” initiative and has now become one of the important destinations for Chinese companies’ overseas investment. South America is rich in renewable energy resources, but has a large power gap and has good investment potential. This paper selects 20 factors of five major factors: politics, economy, law, society, and resources, and uses the entropy method to evaluate and compare the electricity investment environment of the five countries in South America. Combined with the regional power development and planning, the priority investment countries and industries are obtained. In addition, we put forward investment suggestions such as seizing opportunities, building brands, strengthening cooperation, and initiating change.
The non-excavation corrosion prediction model of grounding grid based on particle swarm optimization extreme learning machine
Authors: Li Wenbin , Wang Yong , Feng Yanting , Wang Qing , Xu Xuexia , Li Guowei , Dong Guozhen , Jing Shangqian , Chen Ersong , Fan Xiaoliang , Liu Jianmin
Published: March 2021

The grounding grid is an indispensible part in the eletrical system. Nevertheless, the grounding grid materials are susceptible. Considering the small sample size and strong nonlinear feature of the grounding grid corrosion, we introduced a non-excavation corrosion prediction model based on particle swarm optimization extreme learning machine. This model utilized the extreme learning machine to fast deal with the nonlinear relationship, and utilized the particle swarm optimization to search global optimal solution. Compared with generalized regression neural network and BP neural network, the prediction results of this model are more accurate. Thus, this model might have bright future in improving the accuracy of corrosion prediction of grounding grids.
Research of Available Transfer Capacity of Power Grid Considering Optimal Location-allocation of STATCOM
Authors: Zhang Bin , Wu Hanbin
Published: March 2021

The rational planning of STATCOM can effectively improve the power transmission capacity of the system. In the research of grid transmission capacity considering N-1 safety check, the nonlinear problem is difficult to solve. This paper proposes a calculation method of transmission capacity based on Benders decomposition method. Firstly, the sub-question is added to the core accident screening process to fit the actual grid operation scenario. Secondly, the parallel problem calculation method is used in the sub-problem solving to improve the calculation efficiency. The example shows that the proposed method solves the transmission capacity of the asynchronous grid, and the convergence speed is faster, which verifies the improvement effect of STATCOM on the transmission capacity of the asynchronous grid. The method in this paper can provide calculation aids for grid optimization planning and operation.
Power load forecasting research based on neural network and Holt-winters method
Authors: Fan Jianjun , Liu Xinzhong , Li Zhimin , Wang Xinku , Cao Shengnan , Lei Jiakun
Published: March 2021

Since the electric load shows a very obvious periodicity in time series, increasing the periodic factor in the power load forecasting is a research direction of power load forecasting. It is by adding trend and seasonality (that is, periodicity) to smoothing values that the Holt-winters algorithm improves the accuracy of predictions. In this paper, Holt-winters algorithm and neural network algorithm are used to build power load prediction models respectively, and data of city A in Shandong province is used for testing. Experimental results show that the prediction results of the two algorithms are similar, but the Holt-winters algorithm is slightly more accurate.
Zero Energy Consumption Motor Cooling Device Based on Vortex Tube Effect
Authors: Qi Lei , Yang Yuanhang , Wu Honglin
Published: March 2021

In the daily operation of the industry, due to the long-term operation of machinery, the motor load is too large, resulting in motor overheating. In this paper, a kind of large-scale machine tool is designed, which uses the energy wasted in the non-working state of the large-scale machine tool to convert kinetic energy into air energy to produce compressed air with larger compressibility. Then, the compressed gas is sent to the special vortex tube. By using the structural characteristics of the vortex tube device, the cooling gas with lower temperature can be generated, which can rapidly cool the motor and improve the motor operation. The efficiency and the service life of the motor reduce the probability of motor failure in the actual production process.
Physical properties and basic theory of dielectric
Authors: Fan Shengting
Published: March 2021

At the beginning of human understanding and application of electricity, dielectric materials have been in the world. At that time, however, the dielectric was used only as an insulating material to separate the current. Until the 1930s, the main object of research was insulating materials, mainly focusing on the dielectric constant, loss, conductance and breakdown of insulating materials. After the 1930s, with the emergence and development of new technology, dielectric has been far from being only used as insulation materials to the application, especially the appearance of polar dielectric and widely used, making people’s understanding of dielectric and its category and the past is very different. The research capacity has gradually evolved from the four main parameters of insulators to the study of the internal polarization process. This article from the dielectric polarization, dielectric loss, dielectric conductance and breakdown, dielectric thermal side note relaxation theory and its application of four chapters of the system to learn related content. The properties of dielectric are analyzed from the microscopic point of view, and the related theoretical hypotheses are established to reveal the corresponding macroscopic phenomena. The polarization, loss, conductance and breakdown properties of dielectric are analyzed. The dielectric constant ε, loss Angle tangent tanδ, conductivity γ and breakdown field intensity E are used to describe the properties of dielectric quantitatively.
The effect of planting mode on the growth of pepper in a sunlight greenhouse
Authors: Liu Na , Wei Zhengying , Wei Haoran
Published: March 2021

To adapt to the development of mechanization, a new mechanized planting mode is needed. Taking capsicum as the research object, a comparative test of mechanical east-west ridge planting mode and artificial north-south ridge planting mode was carried out in Hotan sunlight greenhouse with 2ZYZ-2 transplanter. The results showed that transplanting depth of 6 cm, row spacing of 30 cm and row spacing of 40 cm were the best working parameters of the transplanter. The plant height of artificial model pepper was 4.1% and 3.95% higher at 35 and 70 d, while the stem diameter of mechanized model pepper was 5.72% and 3.63% higher at 35 and 70 d. The difference was significant between them. However, the difference between the underground part of the two modes is small, while the accumulation of the mechanized part of the above ground is high and the characters are reasonable. The effective yield of mechanized mode is 2.38 t, which is 11.21% higher than that of manual mode. The two modes of pepper have the same nutritional composition. Therefore, the mechanized planting mode has certain advantages over the artificial planting mode and it can be used in Hotan sunlight greenhouse for pepper production.
Investigation and analysis of ecological environment in the north of Bohai Sea
Authors: Zhou Ruijia , Sha Jingjing , Pan Yulong , Liu Xinyu , Du Xiaoyuan , Bao Mengmeng , Zhao Sheng
Published: March 2021

In order to investigate the ecological environment of Tangshan offshore breeding area (in the north of Bohai Sea), water quality and phytoplankton were investigated and monitored in two consecutive years (2019 and 2020). To evaluate and analyze the water condition of the breeding area, we used the nutrition index (E), Nutritional status quality index (NQI), organic pollution assessment index (A), Biodiversity Index (H’) and Integrated environmental quality index (EQI). The result showed that the range of E was 0.01∼0.97 in May (2019), 0.14∼0.59 in August(2019), 0.25∼0.63 in December(2019), 0.04∼1.21 in August(2020); the range of A was 0.39∼1.33 in May(2019), 0.73∼1.16 in August(2019), 0.87∼1.19 in December(2019), -0.15∼2.33 in August(2020); the range of H was 0.84∼2.11 in May(2019), 1.07∼1.21 in August(2019), 1.92∼2.86 in December (2019), 0.71∼1.47 in August(2020). By calculation, EQI was 94.34 in 2019 and 100 in 2020. The results showed that the nutrient level of the culture area was generally low, and it was in poor nutrition state. The phytoplankton diversity in summer was better than that in spring and winter. The organic pollution degree of the water area was low, but the water quality was good. In conclusion, the environmental quality of aquaculture area was good, which could meet the requirements of functional area.
Preparation and Properties of Straw/PLA Wood Plastic Composites for 3D Printing
Authors: Jiang Jie , Gu Hai , Li Bin , Zhang Jie
Published: March 2021

Based on the single screw extruder, straw/PLA composites with different straw mass fraction, drawing temperature and screw speed were prepared with corn straw powder and PLA particles as raw materials, and FDM printing test was carried out to further study the influence of straw mass fraction, drawing temperature and screw speed on the mechanical properties of straw/PLA composites The results show that the tensile strength of the composite is the best when the straw content is 15%, the drawing temperature is 215°C, the screw speed is 60r/min; the flexural strength of the composite is the best when the straw content is 15%, the drawing temperature is 215°C, the screw speed is 70r/min; the hardness of the composite is the best when the straw content is 10%, the drawing temperature is 195°C, the screw speed is 70r/min.
Research on the Control Path of Event Tourism Pollution in Scenic Spots
Authors: Ding Nan , Zhu Hongbing , Zhao Lei
Published: March 2021

This paper analysed the main environment pullotions of event tourism in the Beer Festival of Liyang scenic spot and its characteristics, lastly put forward the measures for reducing negative effect of event tourism pullotions. The results showed that the main pullotion sources included solid waste, air pollution and soil pullotion. The solid waste of event tourism differs from daily garbage with more reusable materials such as paper, wood, metal and glass. While there are air pollution and soil pullotion in event tourism senic spot differ from sightseeing area. As concentrated pullotions distribution, more water in garbage and high reusability are the characteristics of Beer Festival environmental pollutions, so measures as new recycling technology, small processing stations and standardized management given to cut down the event tourism pollutions.
Response of Lolium perenne Growth to Cadmium Stress
Authors: Yin Peng , Fan Jing , Peng YanJie , Hu Xia
Published: March 2021

The chlorophyll, malondialdehyde and relative conductivity of Lolium perenne had different degrees of physiological response to Cd stress. Lolium perenne had certain physiological adaptability to Cd stress, which could reduce the damage of Cd to Lolium perenne cells. Low concentration of Cd stress could also promote the synthesis of chlorophyll and increase the photosynthetic products. Once the concentration of Cd was too high, the growth of Lolium perenne would be affected. The accumulation of Cd in plants exceeds a certain limit, which damages the physiological function of plants and affects the normal growth of plants. It is suggested that Lolium perenne has a certain remediation ability to cadmium contaminated soil. The experiment can provide a certain reference for the screening of cadmium tolerant plants and the remediation of cadmium contaminated soil.