bluuebunny/crossref_metadata_2025 huggingface dataset:
MWCNT/Nafion/Lead Ionophore Modified Electrode for The Detection of Trace Pb2+ in Coastal Seawater
Authors: Wang Cong , Qiu Chengjun , Qu Wei , Zhuang Yuan , Ya Fudong , Yan Yirou
Published: March 2021

Lead ions in coastal seawater will be enriched in marine organisms, further to endanger human health, so it is essential to conduct detection with high-sensitivity and high-selectivity for lead ions concentration in seawater. In this paper, multi-walled carbon nanotubes (MWCNT)/Nafion/lead ionophore electrode modification materials have been prepared therefore to obtain modified glassy carbon electrodes by a coating method. In order to define trace levels of Pb2+, differential pulse stripping voltammetry (DPSV) was used. Moreover, the experimental conditions i.e. accumulation potential, concentration, pH, accumulation time were in optimized condition. Thereby, results show that the peak current which was obtained in the range of 3~100 μg·L−1 for Pb2+ have a linear relationship with concentration corresponded, with the detection limits of 1.2 μg·L−1 for Pb2+. The modified electrode was used to determine the Pb2+ content in the coastal seawater of the Maowei Sea, and the recovery rate was between 90.4%~104.7%, which provided a novel approach of detection to define trace Pb2+ in seawater.
Application of Virtual Reality Technology in Oral English Teaching for College English Majors
Authors: Li Xi , Xie Ying
Published: March 2021

The purpose of this paper is to construct the application ideas of oral English Teaching for College English Majors based on virtual reality technology, so that the virtual reality technology can enable the education environment, improve the personalized learning experience, and make the oral teaching of College English major conform to the needs of information age, artificial intelligence era and 5G era.
Weather monitoring system based on STM32 and OneNet Internet of Things platform
Authors: Ji Zhenglin , Bin Ren
Published: March 2021

The weather monitoring system is based on the Internet of things platform, which is used to monitor the computer room and other places with strict requirements on environmental factors (such as temperature and humidity). It is of great significance to study how to obtain external meteorological information and internal environmental factors, to conduct visual design, and to deal with abnormal data alarm. The weather monitoring system designed in this paper USES STM32F103ZET6 as the main control chip, and the atk-esp8266 and SIM800C as the auxiliary module, and USES the tft-lcd LCD module as the display (to achieve the purpose of meteorological visualization), develop in the ‘keil u Vision4’ development environment using the C programming language.
Research on the Decision-making of Processing method of Scrap Iron and Steel on Case-Based Reasoning
Authors: Xiong Yingqing , Liu Yi , Chen Yan
Published: March 2021

Recycling of scrap iron and steel is the key steps to realize the sustainable development of iron and steel industry. Considering the existing processing methods of crap iron and steel are extensive, and the processing depends on the experience of the staff or manual measurement, which is easy to cause resource waste and secondary pollution. Aiming at the difficulty of the processing decision-making of scrap iron and steel, a method of scrap iron and steel processing technology decision-making based on case reasoning is proposed. After analysing the sources and classification of the scrap iron and steel, and combining with the main processing methods, the modular case base is founded. Extracting the key features of scrap iron and steel, and using the entropy weight method and analytic hierarchy process (AHP) to calculate the weight of each characteristic element, the comprehensive similarity of the index of case is calculated to obtain the processing method. The feasibility and effectiveness of the decision method are verified by taking the scrap iron and steel processing of a metal resource company as an example.
Precision Control Technology and Device for Miniature Bearing Assembly
Authors: Li Yingang , Li Fei , Pu Yang , Zhu Haitian , Ma Guocai , Jin Xin
Published: March 2021

The traditional assembly equipment of tension link components has a degree of automation and few types of equipment, which have a greater impact on the assembly quality, assembly accuracy, and assembly efficiency of the linkage mechanism. This article firstly combines the current assembly status of the tension connecting rod components in my country and proposes a high-precision press-fitting method for connecting rods with continuous clamping, alignment, press-fitting, and pre-tightening actions. Secondly, an assembly platform for high-precision automatic press-fitting of tension connecting rods was developed and designed, and the structure design of the high-precision tension connecting rod press-fitting platform and the working principle of each module were explained, including a non-destructive clamping mechanism, a two-degree-of-freedom macro-motion platform, and vision alignment module, and other designs. Then through the assembly force experiment, the distribution of the bearing press-fitting force is obtained. The platform can increase the assembly coaxially of the 10mm inner bearing to within 5μm.
The Features of English Discourse in Mechanical Manufacturing and the Exploration of Translation Strategies
Authors: Zhang Chaofeng
Published: March 2021

The analysis of the English discourse of mechanical manufacturing reveals that it is characterized with the professional vocabulary, concise expression and prominent key points. Exploration of the discourse translation strategy shows that it should retain its professional characteristics, achieve flexible translation connotation and rationalize the logic, further to ensure that the value of the discourse is accurately transmitted, and the English medium can be effectively applied in the field of mechanical manufacturing.
Application of Fuzzy Comprehensive Method and Analytic Hierarchy Process in the Evaluation of Network Security Level Protection Research
Authors: Zhi Wei-Wei , Zhou Xin-Xing , Yang Lei
Published: March 2021

The data center is the country’s key information infrastructure and an important cornerstone for the development of informatization. Only by ensuring the security of the data center can the security of important data or sensitive information of the information system be guaranteed. Data center network security level protection evaluation is an important technique and means to check whether the data center is safe. At present, the traditional methods of graded protection evaluation mainly have the problems of differences in understanding of safety indicators, ambiguity of judgments, uncertainty of judgment intervals, and unreasonable division of evaluation indicator weights. In view of the above problems, this paper proposes a method for evaluating the protection of data center network security levels based on fuzzy synthesis and AHP. This method classifies and divides the evaluation indicators in Isobao 2.0 into specific weights, determines the evaluation interval, and achieves quantitative and standardization., Objective grade protection evaluation method. Finally, the method is used to realize the evaluation of the network security level protection of a data center, and an objective and fair evaluation conclusion is given.
Face verification algorithm based on Angular Margin triplet
Authors: Wang Ning , Meng Tao , Chen Xiaoyong , Yuan Dunlei , Yue Qihong , Liu Xiangqian
Published: March 2021

In recent years, the face recognition algorithm based on CNN mainly focuses on the improvement of loss function. This paper improves the softmax loss function from two aspects: one is to normalize the weight and features of the loss function, the other is to introduce in class cosine similarity judgment on the basis of the original loss function. These improvements eventually make the distribution of features within the class closer and the distance between classes as far as possible. The recognition accuracy and generalization ability of the network are enhanced.
Study of hygroscopic expansion of anode readout boards of gaseous detectors based on FR4
Authors: Bortfeldt J. , Dubinin F. , Iengo P. , Samarati J. , Zhukov K.
Published: March 2021

The problem of hygroscopic expansion of FR4 based large-size PCBs is discussed using the example of Micromegas detector. The readout electrodes of the detector located on the anode printed circuit board assumed to have precise dimensions. During the production and delivery process, the readout PCB is exposed to different temperature and humidity conditions. As a result, the PCB size differs from the nominal one at the moment of assembly of the detector. The problem appears to be relevant for any other large-size gaseous detectors with the readout structure based on FR4.

The swelling of two test PCB samples during water absorption is studied. The size of the samples is 650× 500× 0.5 mm3. Both samples have copper strips on one side. The second side is naked on sample 1 and fully covered with a copper layer on sample 2.

The elongation of the samples from dry conditions to 50% RH is measured. The influence of the copper layers on the absorption rate and the value of equilibrium elongation is discussed. It is shown that elongation of sample 1 follows the Fick's law while the absorption process in sample 2 is more complicated. The coefficient of linear hygroscopic expansion of sample 1 is measured and discussed.
Pathways of climate resilience over the 21st century
Authors: Schleussner Carl-Friedrich , Pfleiderer Peter , Andrijevic Marina , Vogel Martha M , Otto Friederike E L , Seneviratne Sonia I
Published: March 2021

The impacts of climate change are affecting human societies today. In parallel, socio-economic development has increased the capacity of countries around the global to adapt to those impacts although substantial challenges remain. Ongoing climate change will continue to result in a pressure to adapt, while socio-economic development could make it easier to do so. Countries’ effectiveness in fostering climate resilience will depend on the pace of both developments under different socio-economic and emission pathways. Here we assess trajectories of adaptation readiness in comparison with the continued emergence of hot days as a proxy for climate change hazards for different emission and socio-economic pathways over the 21st century. Putting the future evolution of both indices in relation to the observed dynamics over the recent past allows us to provide an assessment of the prospects of future climate resilience building beyond what has been experienced to date. We show that only an inclusive and sustainable stringent mitigation pathway allows for effective climate resilient development over the 21st century. Less inclusive or fossil-fuel driven development will not allow for improvements in resilience building beyond the recent past. Substantial differences emerge already in the 2020s. Our findings underscore the paramount importance of achieving the Paris Agreement goals to enable climate-resilient, sustainable development.
Analytical solution of the SIR-model for the temporal evolution of epidemics: part B. Semi-time case
Authors: Schlickeiser R , Kröger M
Published: March 2021

The earlier analytical analysis (part A) of the susceptible–infectious–recovered (SIR) epidemics model for a constant ratio k of infection to recovery rates is extended here to the semi-time case which is particularly appropriate for modeling the temporal evolution of later (than the first) pandemic waves when a greater population fraction from the first wave has been infected. In the semi-time case the SIR model does not describe the quantities in the past; instead they only hold for times later than the initial time t = 0 of the newly occurring wave. Simple exact and approximative expressions are derived for the final and maximum values of the infected, susceptible and recovered/removed population fractions as well the daily rate and cumulative number of new infections. It is demonstrated that two types of temporal evolution of the daily rate of new infections j(τ) occur depending on the values of k and the initial value of the infected fraction I(0) = η: in the decay case for k ⩾ 1 − 2η the daily rate monotonically decreases at all positive times from its initial maximum value j(0) = η(1 − η). Alternatively, in the peak case for k < 1 − 2η the daily rate attains a maximum at a finite positive time. By comparing the approximated analytical solutions for j(τ) and J(τ) with the exact ones obtained by numerical integration, it is shown that the analytical approximations are accurate within at most only 2.5 percent. It is found that the initial fraction of infected persons sensitively influences the late time dependence of the epidemics, the maximum daily rate and its peak time. Such dependencies do not exist in the earlier investigated all-time case.
Research on the Influence on Briquette Characteristics by Blended Coal Preparation
Authors: Guan Duojiao , Liu Siyu , Tang Meiling , Dong Yingnan
Published: March 2021

The characteristics of briquette were not the simple superpose of the fractional coals, and its character was obviously different with the fractional coals. In this paper the research on the influence of the proportion upon volatile, ignition and heat value was done. The experiment results are of great significance to improve the mix proportion and make the mix proportion more clear and reasonable.
Coordinated allocation method of opportunity constraints for thermal power units considering source load uncertainty
Authors: Guan Duojiao , Liu Siyu , Qian Xiaoyi , Ye Peng
Published: March 2021

Cogeneration units usually adopt the “heat based electricity” as the main operation mode in heating season, which will lead to the shortage of peak load regulation capacity and a large number of wind abandonment in power grid.

Therefore, a stochastic optimal allocation method of thermal power units is proposed for the uncertainty of wind power output and load. The wind power prediction method based on interval discretization is adopted. On this basis, the chance constraint model of thermal power unit based on wind heat complementary and heat storage device configuration is proposed, and the coordinated scheduling solution strategy based on real coded quantum evolution is proposed. Finally, the proposed coordinated scheduling strategy is applied to typical thermal power units to verify its effectiveness.
Research on Emergency Method of Power Cyber-Physics Risk Area
Authors: Gao Feng , Zheng Zhuang , Chen Kun
Published: March 2021

With increasing emphasis on the economics of power system operation, economic costs have gradually become an important issue to be considered in the research of risk emergency methods. Although the above method of removing the load of key nodes can effectively suppress the spread of risks, this method is also accompanied by a large amount of load loss, which causes economic waste. In response to this problem, considering the state and topology of the system risk area, this paper proposes emergency measures for node injection power adjustment and load shedding. At the same time, it comprehensively considers the effects and costs of emergency measures, puts forward economic and safety evaluation indicators, and builds an emergency model for cyber-physical power system risk areas. Finally, the differential evolution algorithm is used to optimize the emergency model, and the emergency method for cyber-physical power system risk areas with the best control effect and the lowest control cost is obtained.
ESPRIT-based fast broadband measurement method
Authors: Wang Kai , Zuo Yue , Wang Xingcai , Li Dianyang , Cao Hanwen
Published: March 2021

As the penetration rate of power electronic devices in the power system is getting higher and higher, the broadband characteristics of electrical quantities are becoming more and more significant, and it has caused new network-related stability problems. The monitoring frequency band range and response speed of power system signals are proposed New requirements. This paper uses the super-resolution characteristics of spatial spectrum estimation to propose a short-time window wide frequency measurement method, and estimates the number of signal frequency components through the kurtosis of the signal singular value, and proposes a method based on ESPRIT. The fast broadband data measurement method has shorter response time and higher resolution for fast-changing broadband signals, and at the same time improves the performance of this method in the case of lower signal-to-noise ratio.
Research on distribution network investment allocation method considering actual demand and investment benefit
Authors: Wang Qian , Wang Ronghua , Wan Mingyong , Du Ying , He Puyu , Chen Jinyong , Du Le
Published: March 2021

under the new situation, improving the quality and efficiency has become an important means to enhance the core competitiveness of power grid enterprises and ensure the steady improvement of business efficiency. Distribution network is an important part of the power grid of power grid enterprises, and the current distribution network investment distribution lacks scientific quantitative basis. Therefore, how to scientifically plan the scale of power grid investment and improve the efficiency and efficiency of power grid investment is the foundation to ensure the safe and stable, efficient and economic operation of power grid, and it is also a practical problem to be solved.
Research and simulation of line overvoltage in HVDC transmission system
Authors: Liu Zifa , Wen Xingya
Published: March 2021

The distribution of heavy load area and resource area is seriously unbalanced in China. HVDC transmission system project with long-distance and large capacity transmission characteristics has practical significance in today’s social development. Firstly, this paper discusses the basic knowledge of over-voltage in DC transmission system and analyzes the formation mechanism of internal overvoltage, and enumerates and analyzes the common overvoltage faults at AC side and DC side. Secondly, the electromagnetic simulation software PSCAD/EMTDC is selected to build the model, and CIGRE HVDC standard control model strategy is adopted in each module. Finally, the simulation analysis is carried out, mainly aiming at the AC bus grounding fault of converter station, and the overvoltage waveform under fault condition is recorded. The over-voltage characteristics of rectifier side and inverter side under AC bus fault of converter station are compared and analyzed, which provides reliable suggestions for overvoltage and insulation coordination in future design projects.
Design of coupling monitoring model for operation state of new energy station based on Data Mining
Authors: Wang Nan , Li Qinghua , Sun Shumin , Cheng Yan , Guan Ti , Ma Qiang , Guan Yifei , Wang Shibo , Wang Yuejiao , Yu Peng
Published: March 2021

The development of modern technology has put forward new requirements for the monitoring methods and equipment modernization of new energy power stations in China. As an important part of the construction of new energy, the monitoring method of the new energy station should be designed according to its future development plan to meet the needs of safe use in the new energy station and ensure the healthy operation of the new energy station. In order to meet the above requirements, a data mining-based coupling monitoring model design for the operation status of new energy stations is proposed. Combining modern new energy station monitoring planning and design, this paper develops monitoring models in the construction of new energy stations, promotes the development and optimization of new energy station monitoring design, and applies dynamic monitoring models to the construction of new energy stations to ensure the safe operation of the station.
Smart grid planning suggestions and strategies under the new electric change plan
Authors: Chen Xingliang , Yan Hao , Piao Zheyong , Gao Xiaofeng , Li Haiyan , Jiang Dongxiao
Published: March 2021

New electric change plan is a major event in China’s power grid construction. Based on the basic content of China’s new electric change plan, this article analyzes the existing problems in combination with the current situation of smart grid construction, and proposes corresponding countermeasures for the problems. In general, in order to be able to adapt to the requirements of the new electric change plan, improvements need to be made in terms of management strategies and technical means, so as to fully promote the development of smart grid construction. At the same time, this paper establishes a multi-objective power grid planning mathematical model based on cosine sorting, and uses genetic algorithm to solve the model. Through the analysis of calculation examples and comparison with the results obtained by traditional methods, the validity and rationality of the model are verified, which has certain guiding significance for actual engineering.
Research on time delay compensation method of distributed generation system in active distribution network
Authors: Shi Weimei , Meng Yifeng , Liang Taohua , Dou Yao , Yang Shiqing
Published: March 2021

In order to solve the problems of low compensation accuracy and long compensation time in traditional time delay compensation methods for active distribution network distributed generation system, a new time delay compensation method for active distribution network distributed generation system is proposed. Firstly, the cause of time delay in active distribution network distributed generation system is determined, and then the global characteristics of time delay in active distribution network distributed generation system are extracted by frequency domain method. On this basis, the time delay characteristics of active distribution network distributed generation system are discretized, and the time delay characteristics set of active distribution network distributed generation system is obtained. The continuous function in Banach space is determined by the element method. On this basis, it is discretized, and the time delay compensation model of distributed generation system in active distribution network is constructed. The Lagrange coefficient is used to correct the model to complete the time delay compensation of distributed generation system in active distribution network. The experimental results show that the proposed method has the highest accuracy of 98% and the shortest compensation time of 0.1 s.
Thermal analysis of cooling module based on engine test of thermal balance
Authors: Chang He , Chen Yongjiu
Published: March 2021

Vehicle thermal analysis plays an important role of the overall vehicle development process. To determine energy distribution transformed from the heat released by combustion and build up the model to simulate heat transfer process of the cooling module, the engine bench was put forward to make thermal balance test and the drag test under vehicle target working conditions. It was found through the experiment data that the heat absorbed by the cooling system changed by the coolant temperature of the inlet. As a result, the correction map was established for the control system of cooling module that can be changed by the engine rotation speed, output torque and power value. A 1D -3D simulation model was built up by experiment data and coupling computing method. Based on the simulation model of cooling module that was verified by the thermal balance experiment data, the research and analysis were carried out on the performance of cooling module under the conditions of different environmental temperature and working state of air-conditioning system. The conclusion of interaction effects was made, which have important engineering value for the development of intelligent cooling module control system.
Design of geomagnetic simulation coil for naval eddy current magnetic field measurement
Authors: Liu Liu , Liu Sheng-Dao , He Bao-Wei
Published: March 2021

The research on ship eddy current magnetic field measurement is mostly based on magnetic simulation method. In view of the current used in degaussing station low magnetic compensation degaussing coil cannot meet the requirements of the homogeneous degree of the eddy current magnetic field measurement, this paper USES the particle swarm optimization algorithm, with magnetic modeling of coil system uniformity of evenness as objective function, by means of iteration, the parameters and the number of turns to the position of the coil system parameter optimization calculation, and find the optimal solution. According to the optimal solution, combined with the characteristics of the experimental site and the actual construction of the coil system, the uniformity of the magnetic field generated by the coil system was simulated, and a relatively uniform magnetic field space with the uniformity of more than 95% in the central region was established.
Comparative Evaluation of Stocking Products Based on Product Life Cycle Assessment
Authors: Shao Zhi-Yuan , Liu Lin
Published: March 2021

Objective In order to analyze the difference of environmental benefit between different processes of silk stockings products, the article puts forward the method of product life cycle analysis to provide reference for the subsequent selection and optimization of production process of silk stockings products. Methods The representative target products in silk stockings were selected, and the full life cycle model of production, use and waste of target products was established by product life cycle method. The two technologies were compared and evaluated quantitatively by analyzing relevant environmental impact indexes, and the reasons for the difference were analyzed by refining the product production process. Conclusion Dope dyed stocking fabric is more environmentally friendly than traditional dyed stocking fabric. The production process of a product is the link that has the greatest impact on the environment in the entire life cycle and the main link that causes the environmental differences between the two processes. The product life cycle model established in this paper can be used as a reference for the life cycle analysis of other similar fabric products, and it proposes a normalized index suitable for evaluating environmental benefits in other industries.
Impedance measurement circuit based on improved voltage vector ratio method
Authors: Wang Kai , Wang Shunjiang , Zuo Yue , Wang Xingcai , Gao Ming
Published: March 2021

China’s inductance value is traced back to the national inductance working base. In addition, in China’s electromagnetic metrology standard system, the inductance working standard can only be traced back to the source at 1kHz. The values at other frequencies are obtained after frequency conversion according to the distribution parameters of the inductance reference. The most accurate digital bridge is the 1689MRLC digital bridge, with impedance measurement accuracy of 0.02%, d and q measurement accuracy of 0.0001, and programmable test from 12Hz to 100kHz. Since the researchers need to work on the benchmark to ensure that the transmission capacity reaches 0.01% in the broadband (50 Hz-2.5 kHz), the measurement system needs to be redesigned.
Simulation Research on the Role of Energy Revolution in the Rise of China’s Five Central Provinces
Authors: Zhao Jinhui , Wang Yufeng , Xia Yongbo , Zhang Lijun
Published: March 2021

China’s energy revolution strategy serves as both a driving force and a hindrance to the rise of central China. Based on the six-dimensional data of GDP, industrial structure, urbanization, energy efficiency, per capita income and energy consumption of the five central provinces, this research sets three levels of growth rate, namely high, medium and low growth rates. With GDP growth as the key sub-scenario, a total of 13 rising models from SE11 to SE34 are established to simulate the high-quality rise of the five central provinces against the background of energy revolution. The results indicate that the path of high-quality rise of central China varies from SE11 to SE25, that is, from high-speed economic growth to benchmark growth model. For the model of rapid economic development, the industrial structure will be upgraded and the energy efficiency will be maximized. With the energy revolution, the emission of carbon dioxide will reach its peak in 2020. However, the adjustment of industrial structure promoting energy efficiency will be challenging, which will also cost a huge amount of energy. For the benchmark growth model, GDP growth rate is lower than that of the rapid development model, but the energy consumption is reduced, and the adjustment of industrial structure and the improvement of energy efficiency is less challenging. Improving energy efficiency has a higher effect on energy saving than upgrading industrial structure. Through energy revolution, the proportion of renewable energy will reach 23.06% in 2035, and consequently the emission of carbon dioxide will reach its peak two years ahead of schedule.
Research on Evaluation Method of Application Maturity of BIM Technology in Transmission and Distribution Engineering Based on Fuzzy Theory
Authors: Zhang Duo , Wang Zhengping , Yin Chenlei
Published: March 2021

With the continuous development of social economy and science and technology, the promotion and application of BIM technology in the whole process of power transmission and transformation projects is also increasing. Scientific and reasonable evaluation of the application maturity level of BIM technology in power transmission and transformation projects, and further improving the effective integration of BIM technology and power transmission and transformation project construction management, are of great significance for improving the quality of project construction and management efficiency. Therefore, on the basis of systematically sorting out the application scenarios of BIM technology in power transmission and transformation projects, this paper constructs a fuzzy theory-based method for evaluating the application maturity of BIM technology in power transmission and transformation projects, which can effectively guide the promotion and application of BIM technology and further improve transmission construction quality and management efficiency of substation projects.
Synchronous measurement technology of source-grid-load in renewable energy power system
Authors: Wang Kai , Zuo Yue , Li Dianyang , Wang Xingcai , Li Quanzheng
Published: March 2021

In this paper, the technology of synchronous phasor measurement and its application in power system transient stability prediction and control, state estimation and dynamic monitoring, fault location is introduced. The construction method of wide area measurement system based on synchronous phasor measurement technology is puts forwarded. The important role of synchronous phasor measurement technology in these fields and its significance to power system security are analysed.
Application of Electronic Diagnosis Technology in New Energy Vehicle Maintenance
Authors: Li Mengyin , Bai Chaofeng
Published: March 2021

With the continuous development of modern society and economy, the speed of new energy vehicles is also rapid, and the number is increasing rapidly. To determine the fault content in a short period of time during maintenance of this type of car, the application of electronic diagnostic technology is essential. This article summarizes the advantages of applying electronic diagnostic technology in the maintenance of new energy vehicles based on previous work experience. The author discusses the specific aspects of electronic diagnosis technology in the maintenance of new energy vehicles from four aspects: application in chassis output power detection, application in automobile circuit maintenance, application in automobile electric motor maintenance, and application in automobile power battery maintenance application content.
Design of automatic robot with electrolytic wiring for isolating circuit breaker
Authors: Zhu Shenglong , Li Binbin , Zhang Chenchen , Qin Shaorui , Liang Wei , Chen Haigen
Published: March 2021

Isolation circuit breakers are used in power stations to isolate voltages, and isolate the equipment to be repaired from live parts to form a safe operating space. In order to meet the needs of on-site maintenance and test of the new generation intelligent substation, avoid the need to stop other electrical equipment during the maintenance of the isolation circuit breaker, reduce the scope of equipment power failure and shorten the system debugging period, this paper proposes a design method of automatic live line disconnection robot for isolation circuit breaker, which can meet the requirements of bus clamp removal and installation, and improve the isolation of new generation intelligent substation Operation and inspection level of circuit breaker. The specific method is to design a mobile robot lifting platform, through the cooperation of manipulator, controller, arc strike rod, camera and other tools to realize the live line disconnection operation of three-phase bus. In this paper, 3D modeling and simulation show that the robot design scheme is feasible.
Evaluation and Analysis of Total Factor Input and Output of Power Grid Enterprises under the New Situation
Authors: Yu Jing , Lin Shiyuan , Huang Fenghui , Han Yaru , Tu Xiazhe , Liu Lin
Published: March 2021

The current economic and social development and changes in internal and external environments have brought severe challenges to the operation of power grid companies. By studying the input-output relationship of all factors in power grid companies, from the perspective of effectiveness, efficiency, and benefit, this paper constructs an input-output evaluation index system, introduces analytic hierarchy process and entropy method for weight calculation, uses weighted average method to construct input-output evaluation model, and conducts empirical research with relevant data and information in a certain area as an example. The research results can provide auxiliary decision-making support for the scientific and reasonable allocation of resources, and realize the clarity of input and output effects of power grid enterprises, scientific and rational investment arrangements, and lean business management.
Experience and Enlightenment of Japan’s Emergency Power Supply Guarantee Mechanism
Authors: Han Zhang , Song Xue , Li Ma , Xiaoxuan Zhang
Published: March 2021

Japan is a country prone to natural disasters such as earthquakes, tsunamis, and typhoons. Electricity is the key material basis for production, life and emergency management, so the reliability and stability of its supply is an important content of Japan’s disaster protection. In recent years, people have paid more and more attention to maintaining a normal and independent life even after the power and natural gas infrastructure has stopped. Therefore, the concept and practice of emergency power supply have been circulated and widely implemented in Japan for a long time. This paper summarizes the concepts, legal standards, development history, main methods, work of power grid companies, development trends, etc. of emergency power supply in Japan, and provides relevant experience and inspiration for the development of emergency power supply in China.
Prediction Technology of Payment Terminal State Based on Grey Model
Authors: Xu Mingfeng , Yuan Shaohua , Sun Xing , Wang Shaowei
Published: March 2021

This article analyzes the characteristics of power payment terminal operation. Grey model theory is used to predict the change trend and specific values of the multi-dimensional status information of the equipment. Firstly, the correlation analysis method is used to extract the core data with lower correlation degree from the massive state data. Secondly, the development trend of the data is predicted by the gray prediction model. Finally, the effectiveness of the gray model is verified by actual field data.
Numerical simulation analysis of leakage gas cloud explosion in LPG tank farm
Authors: Luo Zhenmin , Zhang Siqi , Gao Shuaishuai
Published: March 2021

a LPG tank farm model was established by FLACS software to simulate the leaking gas cloud explosion. The propagation process of explosion flame and the change process of explosion overpressure field and temperature field were studied under the influences of different leakage rate, wind speed and wind direction. The results show that, the larger the leakage rate is, the larger the impact area of gas cloud explosion is, the higher the explosion overpressure and temperature are. When the wind speed is larger than 4 m/s, the higher the wind speed, the faster the heavy gas will be diluted by the ambient gas, and the explosion will be suppressed. Under the influence of different wind directions, the impact area of explosion is also different.
A nanorod-like KTi8O16 catalyst for soot combustion
Authors: Li Qian , Lv Yanan , Li Yuebin , Zhang Nana , Zhang Jun , Zhang Zhaoliang
Published: March 2021

A nanorod-like KTi8O16 catalyst was successfully prepared by combustion method and applied for removing hazardous diesel soot. The cryptomelane structure of KTi8O16 is confirmed by X-ray powder diffraction (XRD). The straight and smooth crystalline nanorods with the diameter of 180 nm are identified by transmission electron microscopy (TEM) and (200) facet is observed to be preferentially exposed. K cations are not freely present in cryptomelane structure of KTi8O16 derived from X-ray absorption fine-structure (XAFS) results, possibly due to the confinement or interaction of K with Ti element. By temperature-programmed oxidation (TPO) experiments, its catalytic soot combustion performance was evaluated, with T
10 and T
m of 435°C and 511°C, which are decreased by 19°C and 45°C respectively compared with pure anatase TiO2. K+ species are deduced to serve as the active sites in the catalytic soot oxidation reaction, which are confined in the channels of the nanorod-like KTi8O16.
Process optimization and thermal risk analysis for 1,3,5-trihydroxy-2,4,6-trinitrobenzenen synthesis
Authors: Wang Yang , Wu Wenqian , Guo Zichao , Lin Qiuhan , Chen Liping , Chen Wanghua
Published: March 2021

1,3,5-Trihydroxy-2,4,6-trinitrobenzene (TNPG) is an important precursor material for high-performance explosive 1,3,5-triamino-2,4,6-trinitrobenzene (TATB). In this work, TNPG was synthesized by nitration of phloroglucinol (PG) using the nitrating agent of ammonium nitrate (AN) and sulfuric acid (H2SO4) mixture. The reaction rate and thermodynamics of the nitration reaction was studied. On the basis of a series of reaction calorimetry experiments and thermal stability tests, the feeding sequence and reaction temperature were optimized. The feed sequence of dosing PG/H2SO4 solution into the AN/H2SO4 solution is better than the opposite feed sequence. The best reaction temperature is at 5°C. The highest yield of ˜93% TNPG was obtained. In addition, the thermal risk analysis revealed that the thermal risk at the optimal operating condition was low.
Influence Factors on Viscosity Loss of Injection System in A Test Area
Authors: Yuan Dan Dan
Published: March 2021

As the first ASP flooding test in the transitional zone, it was put into pre polymer flooding in October 2018. However, the viscosity of single well cannot meet the design requirements at the initial stage of production. In view of the viscosity loss of polymer solution in the process of surface injection, by investigating the concentrated viscosity of each node of polymer injection process and single well injected outside the station, this paper analyzed the field test data and water quality report, found out the key links affecting the viscosity of polymer solution, and proposed various technical measures to reduce the viscosity loss. It is found that the viscosity loss is mainly formed after the mixing of polymer mother liquor and high-pressure sewage, and it is concluded that the main reason is the influence of injected water quality. Based on the analysis of salinity, bacterial content and iron ion in water quality, it is found in this paper that the viscosity of polymer injection increases by 40% when a fresh water pipeline is laid and the waste water is diluted on site.
Vapor-pressured induced synthesis of chemically bonded Fe1-xS/N-doped carbon composite nanoflakes as high-capacity, ultralong-cycle-life, and high-rate lithium-ion-battery anode
Authors: Han Meisheng , Li Jiayang , Li Zhenwei , Yu Jie
Published: March 2021

Ascribed to its high reversible capacity, Fe1-xS is taken as a promising lithium-ion-battery (LIB) anode material. Regrettably, unsatisfactory electrical conductivity, large volume change, and structural deterioration upon cycling of Fe1-xS severely delay its commercial application. Herein, a one-step vapor-pressured induced route is first proposed for synthesizing Fe1-xS/N-doped carbon composite nanoflakes (Fe1-xS/NC), in which Fe1-xS nanoflakes with an average thickness of 30 nm are tightly coated by N-doped carbon layers via chemical bonds of Fe-N-C, by pyrolysis of mixture of iron isooctanoate dissolved into dimethylformamide and thiourea in a sealed vessel. As LIB anode, the Fe1-xS/NC exhibits a high reversible capacity of 1106.8 mAh g−1 at 0.1 A g−1, an ultralong cycling life (722.7 mAh g−1 after 1400 cycles with 0.0098% capacity loss per cycle at 1 A g−1), and an excellent rate performance (219.8 mAh g−1 at 20 A g−1). This excellent performances may arise from its structural advantages that the smaller Fe1-xS nanoflakes are tightly wrapped into N-doped carbon layers via Fe-N-C bonds, which can increase lithium ion storage sites, electrical conductivity, and structural stability.
Judgement and calculation method research of onset of nucleate boiling under tube outside pool boiling condition
Authors: Liu Yanbin , Meng Xiangyu , Wang Xuesheng , Yuan Yuyang
Published: March 2021

Pool boiling is a common phenomenon and widely utilized to realize the heat transfer process in different fields. In advanced nuclear power plant such as the AP1000 passive safety system, pool boiling is also used to fulfil the residual heat removal function through the Passive Residual Heat Removal Heat Exchanger (PRHR HX). The onset of nucleate boiling (ONB) point is one of the key points during heat transfer mechanism changing process. The judgement and predicted method of the ONB under tube outside pool boiling condition is still a difficulty and needs further investigation. In this paper, the heat transfer characteristic of the ONB point is experimentally studied by combining with high speed camera technology. Base on the observing and calculating results, the ONB point is judged. The applicabilities of different ONB point predicting correlations are estimated and an empirical correlation predicting wall superheat degree more accurately is developed.
Study on Mechanical Properties of P92 Steel Welded Joint of the Main SteamPipe of Ultra Supercritical Unit After 50,000 Hours Service
Authors: Li Xinmei , Zhang Zhongwen , Du Baoshuai , Li Wen , Suo Shuai , Zou Yong , Yin Zhiyi
Published: March 2021

Combined with a scanning electron microscope, this paper carried out a tensile test and a bending test to study the mechanical properties of P92 steel welded joint of the main stream pipe after the joint was in service for 50,000 hours. The results show that the tensile strength and hardness of the P92 steel weld metalare higher than those of the base metal after it was treated at a high temperaturefor 50,000 hours, but the plasticity is lower than that of the base metal. This is related to the precipitation and growth of Laves and M23C6phases in the steel during treatment; after the metal was treated at a high temperature for 50,000 hours, the number of Laves phases is larger and the size is bigger than that in the base metal. The Laves phases are precipitated rapidly along the austenite grain boundary and martensite lath boundaryand then distributed in the grain boundary, lath boundary, and plate strip boundary, reducing the strength and toughness of the matrix.
Heat transfer phenomenon and characteristics study of C-shaped tube with nucleate boiling in water tank
Authors: Meng Xiangyu , Liu Yanbin , Wang Xuesheng , Cao Jiaming
Published: March 2021

The Passive Residual Heat Removal Heat Exchanger (PRHR HX) is an important equipment of the passive safety system in advanced nuclear power plants such as AP1000. Heat transfer phenomenon and characteristics study of the PRHR HX has received more and more attention. However, the research of transient heat transfer under C-shaped tube outside pool boiling condition is insufficient and needs further investigation. An experimental facility was built and a series of experiments were conducted. Distributing and changing tendencies of some important parameters including tank water temperature, tube wall temperature and heat transfer coefficient were obtained and analyzed. This study can provide a reference for the thermal hydraulic design for the PRHR HX in nuclear power plant.
Prediction of human thermal sensation based on improved PMV model
Authors: Xu Gang , An Qiqi
Published: March 2021

In the traditional PMV model, the calculation of human skin temperature is only related to the level of human activity. In fact, human skin temperature is related to many factors such as evaporative heat dissipation, radiation and convective heat transfer of human skin. Therefore, it is necessary to introduce human thermal physiological model to modify the skin temperature in PMV model. In addition, considering the impact of human activities on human metabolic rate, the formula of calculating human metabolic rate obtained from Pandolf was introduced to improve the original PMV model. Finally, the model is validated and analyzed with published experimental data. The results show that the improved model can accurately predict the thermal sensation of human body under the test condition, and the predicted thermal sensation is closer to the experimental value than the original PMV model.
Preparation of nitrogen doped CNTs porous carbon materials based on MOF in situ growth and its application in lithium sulfur cathode
Authors: Sun Kaixuan , Liu Shuangke , Wang Danqin , Hong Xiaobin , Li Yujie
Published: March 2021

Porous carbon structure is widely used as sulfur carrier to improve the cycle stability and rate performance of lithium sulfur batteries. However, due to the amorphous carbon structure of porous carbon nanostructures, it is still a big challenge for porous carbon nanostructures to obtain high sulfur content and high sulfur surface density. In order to improve the electronic conductivity of porous carbon, maintain its long cycle life and good rate performance, we prepared N-doped graphitized CNTs by high temperature sintering. CNTs encapsulated bulk porous carbon was prepared using ZIF-67 and melamine as precursors(Co-NC@CNTs/S). The CNTs are “slubby” structure and the tube wall is graphite. Due to the unique structure of Co-NC@CNTs, the positive cathode of Co-NC@CNTs/S has better electrochemical performance than Co-NC/S positive cathode. Under the condition of high sulfur (82wt%), the cathode can not only obtain high discharge capacity (1293mAhg−1 at 0.1C) and excellent rate performance (727.8 mAhg−1), but also achieve long cycle stability of more than 100 cycles (capacity decay rate of each cycle is 0.17%).
Compare of arsenicals form in warfare agents’ destroyed residue by controlled detonation and heating blasting technology
Authors: Ma Bin , You Lijuan , Xu Yong , Xu Jie , Wang Xuefeng
Published: March 2021

As typical arsenicals, lewisite, diphenyl chloroarsine, diphenyl cyanoarsine occupy a large proportion of Japanese abandoned chemical weapons in China. Both heating blasting technology and controlled detonation disposal are regarded as the effective disposal to destroy the molecular structure of chemical agents. In different forms of arsenic product, two destruction methods for chemical weapons have been discussed. Analytical morphology of arsenic showed that arsenicals can be oxidized better and less organic arsenic residue can be reduced by heating blasting technology.