bluuebunny/crossref_metadata_2025 huggingface dataset:
A multi-objective optimization method for aerospace product research and development process based on particle swarm optimization algorithm and critical path algorithm
Authors: Liu Yan , Yin Bo , Jia Dongning
Published: January 2021

In order to realize the multi-objective management objectives in the production cycle of aviation products, this paper combines particle swarm optimization algorithm and critical path optimization algorithm to carry out multi-objective optimization on the research and development process of aviation products. First, calculate the start time of each process by the critical path method and construct the initial population. Then construct the fitness function. Finally, particle swarm optimization is used for optimization, and through continuous iteration, the optimal combination that can achieve multi-objective optimization is obtained. Through the optimization experiment on the research and development process of aviation products, the global optimal research and development process calculated in this paper can shorten the production period by 32.4% and reduce the cost by 41.1%. Therefore, the multi-objective optimization scheme based on hybrid optimization algorithm proposed in this paper has theoretical and practical significance for the model management of the whole life cycle of aviation products.
Moving Object Detection Algorithm based on Improved Visual Background Extractor
Authors: Yang Xuewen , Liu Tangyou
Published: January 2021

Aiming at the problems that the ViBe algorithm causes error detection when the camera jitter, ghosts appear when processing moving targets, and the detected moving targets are incomplete, an improved ViBe algorithm based on motion compensation is proposed. In the background modeling stage, the motion compensation method based on KLT is used to obtain background model to enhance the robustness of the algorithm to the dynamic background. In the foreground detection stage, combined the background model of the current pixel with 8 neighbor pixel background model, by the double discriminant algorithm to eliminate ghost areas caused by detecting the real background points as foreground points, introduce OTSU algorithm to obtain the optimal threshold for foreground detection. In the post processing stage, filter the connected components for segmentation masks and update models to limit the wrong background points scattered in the foreground.Finally, the connected domain is repaired by morphological opening operation. The results show that the algorithm can effectively eliminate the interference caused by camera jitter, and suppress the ghost phenomenon to obtain more accurate foreground images.
Improved ECO Algorithm Based on Residual Neural Network
Authors: Qi Huifang , Wang Changmeng , Li Bo
Published: January 2021

Video target tracking is one of hot fields of computer vision, and its application is also very extensive. However, due to the complexity and variability of tracking environment, which brings some challenges to the research of target tracking. ECO(Efficient Convolution Operators) Algorithm is proposed based on convolutional neural network in three aspects. Firstly, residual neural network ResNet50 is adopted instead of convolutional neural network to extract the appearance features of target, and deeper residual neural network is applied to obtain more abundant target semantic information, so as to improve the tracking effect of tracking algorithm.Secondly, sample space classification strategy is improved. Different weights are assigned to shallow feature and deep feature, which make the deep feature play a more important role and improve the effect of target tracking. Finally, the method of scale estimation is improved so that better bounding boxes can be estimated with the scale changing. Experimental results show that the distance accuracy and success rate of the algorithm.
Photovoltaic output prediction of regional energy Internet based on LSTM algorithm
Authors: Weng Geping , Pei Chuanxun , Ren Jiaorong , Ye Chen , Cui Qinyue , Qing Hua , Liu Yuan , Guan Xinyu
Published: January 2021

By the huge development of large scale and modular photovoltaic power generation, accurate photovoltaic (PV) output prediction can help PV power station, scheduling department and power system operate safely and economically. In the process of PV output prediction, the data density is large, and the output data is relatively regular. Therefore, this paper considers the use of long-termed and short-termed memory neural network algorithm to optimize the problem of algorithm gradient vanishment in recurrent neural network, and complete the output prediction of PV power in the regional energy Internet on the basis of historical output data. In this paper, LSTM algorithm is used to analyze the historical output data of PV stations in an industrial zone of a certain city. It can be found that LSTM algorithm has good adaptability for short-term PV output prediction, which can meet the needs of application.
The Wolf pack assignment rule based on ant colony algorithm and the path planning of scout ants in complex raster diagra
Authors: Zhu Yu , Zhu Liucun , Long Yong , Luo Junqi
Published: January 2021

The traditional ant colony algorithm based on raster algorithm has slow searching speed and convergence speed in the problem of robot path planning, and it is easy to fall into the problem of local optimal. In order to solve this problem, an improved ant colony algorithm based on Wolf distribution rules and reconnaissance ant strategy is proposed, which can adjust the pheromone coefficient adaptively and obtain a more suitable proportion of pheromone allocation. Experiments show that this algorithm is superior to the traditional ant colony algorithm in terms of optimal path searching speed, quality and convergence speed in simple and complex environments.
Voltage sag severity analysis based on improved FP-Growth algorithm and AHP algorithm
Authors: Lin Yan , Lin Fang , Huang Daoshan , Fang Xiaolin
Published: January 2021

In order to accurately evaluate the impact of voltage sag on both utility and customer, a data mining analysis method based on improved FP-growth algorithm and AHP algorithm is proposed. The proposed method selects and classifies voltage sag characteristics and combines voltage sag severity level to construct a data mining analysis framework. The improved FP-growth algorithm is used for data mining on voltage sag events to improve the efficiency of mining. The association rule matching model is constructed by AHP algorithm for evaluating the voltage sag severity level, which improves the accuracy of the evaluation results. Finally, a practical example verifies the practicability of the proposed method.
Inter-annual and Inter-decadal Variation of Temperature during 1960-2013 in Dabie Mountain of West Anhui Province
Authors: Zhao Yongmei , Luo Yuan , Luan Xiaoxiao , Cheng Xinyu
Published: January 2021

The inter-annual and inter-decadal variation of temperature in Dabie Mountain of West Anhui Province is analyzed according to actually measured data of daily average temperature, maximum temperature and minimum temperature during 1960-2013 in five meteorological stations in Dabie Mountain. Results show: The quarterly and annual average temperature, average maximum temperature and average minimum temperature (except the average maximum temperature in summer) in Dabie Mountain of West Anhui Province are all in a rising tendency. The annual average temperature increases remarkably at an amplitude of 0.165°C/10 years. The increase amplitude of average minimum temperature is 1-2 times of the average maximum temperature, and the daily range shows obvious reduction. The annual extremely maximum temperature and extremely minimum temperature are both on the rise, and the amplitude of the latter is larger than that of the former. From 1960s, the average temperature, average maximum temperature and average minimum temperature turned rising in Dabie Mountain of West Anhui Province. The abnormally warm years are 1967, 1968, 206, 207, 1998 and 2013, while the abnormally cold years are 1967 and 1981.
Consistency Analysis of two Lightning Systems in Hubei Province
Authors: Li Guoliang , Li Jun , Li Xiang , Yuan Fang
Published: January 2021

In order to study the Hubei lightning locating system detection efficiency in 2015-2016, this paper adopts the method of mathematical statistics, compared and analyzed the distribution structure, detection efficiency, space-time distribution and lightning current characteristics between two lightning systems. The results show that the more sub-stations and the smaller the baseline distance are, the higher the detection efficiency is. The average number of cloud and ground lightning in 3D lightning locating system is 86.8% more than that in 2D system, and the proportion of positive ground lightning is slightly higher than that in 2D system. The positive and negative flashover of the 3D system are between 0-90kA, Positive current of 10-20kA and negative current of 20-30kA are the most. The positive and negative lightning in 2D system are between 10-100kA, the current has the highest percentage of 20-30kA and the lowest percentage of 10-20kA. The 3D system detection efficiency and lightning density distribution are better than 2D system. two sets are consistent in lightning time characteristics, geographical distribution and intensity distribution rules, which plays an important role in lightning disaster investigation, lightning monitoring and early warning and other business applications.
Rainfall Variety and its Effect to Runoff Reduction of Status Year in the Region from Hekouzhen to Longmen
Authors: Jin Shuangyan , Ma Zhijin , Zhao Wenrong , Gao Yajun , Guo Shaomeng
Published: January 2021

The natural runoff of the Yellow River has been reduced sharply since 2000. Based on rainfall network of 1966 and 1977 are built on GIS platform, the trend of rainfall variety in 1956∼2013 is analyzed. The turning point of runoff of natural period and human activities impact period in the eighteen tributaries was analyzed with the method of orderly clustering and MWP test and so on. The model was established with the data from 1956 to the turning point year, and the runoff during this period was regarded as benchmark value. The runoff variety and the impacts brought by rainfall in the status series from 2007 to 2013 were analyzed by equation of runoff division. It is showed that natural runoff reduced 5.411 billion cubic meters, among which brought by rainfall not negative value but increased 0.424 billion cubic meter.
Annual natural runoff forecast of Panjiakou Reservoir
Authors: Wang Zhe , Guo Huifang , Li Taotao , Zhu Jingsi
Published: January 2021

Haihe River Basin is an area with frequent droughts and floods in China. There is a serious shortage of water resources in the Haihe River Basin. The average annual water resources in the basin are 37.2 billion cubic meters, with a per capita share of 305 cubic meters, 1/7 of China. which is one of the serious water shortage areas in China. Panjiakou Reservoir is a large reservoir in the Haihe River Basin, with a water storage capacity of 2.93 billion cubic meters. It is responsible for the water supply of Tianjin, Tangshan and other large and medium-sized cities. The reasonable operation of Panjiakou Reservoir plays an important role in Haihe River Basin. In this paper, the support vector machine model is used to predict the runoff of Panjiakou Reservoir. The prediction results can provide reference for the reasonable operation of Panjiakou Reservoir.
The spatial distribution of soil nutrients matter and variation characteristics of Datong Abandoned Coal Mine area in Huainan City
Authors: Sun Xianbin , Sun Liangping , Zhang Xing , Li Guangyao , Yu Maohui
Published: January 2021

This paper describes the analysis of nutrients matter in soil sampled from Datong abandoned mining area in Huainan City. Spatial interpolation in GIS is applied to the revelation of spatial distribution of nutrients matter. Results show that: In abandoned land in Datong coal mining, the level of available phosphorus in soil was very short and the following grades, and the level of nitrogen was short grades, and the level of organic matter was medium and the following grades. Distribution of these heavy metals present a stronger spatial relevance because their spatial pattern are mainly influenced by natural factors such as complex micro-geomorphology, vegetation, topography, strongly human disturbance and other structural factors. All of spatial variability was middle and small scale. Characteristic of spatial variation was relation with the complex distribution object. Random factors, such as sampling interval, soil type and so on, play a relatively greater role in spatial variability of nutrients matter.
Empirical Study on Environmental Pollution effect of FDI
Authors: Yan Xiaoming
Published: January 2021

This paper combs the relevant theories and literature, and analyses the three impact mechanisms of FDI on environmental pollution which includes economic scale, technology and structural effects , This paper selects foreign direct investment panel data of 29 provinces in China in 2009-2017, explores the impact of foreign direct investment on China’s environmental pollution, verifies that the “pollution shelter” hypothesis does exist in China, and concludes that the inflow of foreign direct investment aggravates China’s environmental pollution, and based on this, the paper puts forward targeted policy recommendations.
Analysing PM2.5 concentrations using MODIS and monitoring measurements for Shanghai area
Authors: Miao Lizhi , Wen Yi , Ren Yanhui
Published: January 2021

Analyzing PM2.5 concentrations from remote sensing images and surface measurements using the model of aerosol optical depth (AOD) is a popular method to evaluate the exposure to PM2.5 in some geographic regions. For analyzing the ground-level PM2.5 density on a daily basis using satellite-derived AOD in Shanghai area, we use Aqua MODIS (Moderate Resolution Imaging Spectroradiometer) to obtain the AOD values at 3-km resolution by dark pixel. However, AOD values are missing in many regions caused by processing method and imaging process. Interpolating the AOD values to extend the coverage area of MODIS and integrating the surface measurements, we filter the AOD values and PM2.5 measurements. The analysis results indicate that the correlation coefficient is 0.54 in Shanghai area. Satellite derived mean PM2.5 for Shanghai was 42.69 ug/m3 during the study period (Jan 2016 to Dec. 2018), whereas mean PM2.5 is highest in winter period (61.68 ug/m3), and lowest in autumn period (31.4 ug/m3) over study period in study area.
Wavelet Analysis on Temperature and Precipitation Changes in Dabie Mountain of West Anhui
Authors: Zhao Yongmei , Luo Yuan
Published: January 2021

The wavelet analysis method is applied to analysis of multi-level time change characteristics of temperature and precipitation in Dabie Mountain based on the meteorological observation data of five stations in Dabie Mountain from 1960 to 2013. According to results, the temperature shows oscillation periods of 22 years and 10 years in Dabie Mountain, West Anhui. While the precipitation shows an oscillation period of26 years. The change relationships of temperature and precipitation are not the same based on different time scales. From the scale of 3 years, to 10 years and 20 years, the out-of phase becomes weaker. The tendency of consistence appears gradually.
Numerical analysis of concrete temperature stress at different loading ages
Authors: Liu Longlong , Zhang Zhaosheng , Huangfu Zehua , Huang Dahai
Published: January 2021

This paper investigates the thermal stresses of low-heat cement concrete under different loading ages, and thermal stresses were calculated with different compensation cycles by the Boltzmann superposition principle. An application of the Boltzmann superposition principle on the temperature stress test shows how the formulation may be used to evaluate the mechanical properties of low-heat cement concrete and how the accuracy of calculated stresses applies to measured stresses. The comparison between measured stresses and the simulated results shows good agreement under different compensation cycles, which indicates that the thermal stresses can be well estimated via the line superposition. Furthermore, these experiment results indicate that the maximum compression stresses increase rapidly with the increment of curing ages while the cracking stresses have subtle differences.
Research on slope investigation using high density resistivity method
Authors: Liu Fei , Yang Zhong
Published: January 2021

In this paper, high-density resistivity of the north bank of Huangming Reservoir in Yuyao City was detected by the Wenner device. Through the detection of multiple sections in the longitudinal and transverse sections, the distribution rules of the rock mass of the slope are summarized, and the weathering grade of the rock is judged. The research results will provide a strong basis for the disaster prevention and mitigation work in the later period.
Study on the adhesion between activated kaolin modified asphalt and mineral materials
Authors: Bao Huiming , Wu Chunyan , Zhang Yimin
Published: January 2021

The mass fraction of kaolin was 3%, 5%, 7%, 9%, 11%, 13% and 15%, respectively. The three indexes of kaolin were tested. The results showed that after kaolin was added, the penetration, softening point, ductility and deformation resistance of matrix asphalt were decreased. In addition, indoor adhesion test was conducted to analyze the adhesion of modified asphalt of granite and limestone with different kaolin contents, and the adhesion of modified asphalt in distilled water and 5%NaCl solution were compared. It is found that adding kaolin can improve the adhesion between asphalt and aggregate. Through a comparison of properties, it is suggested that the content of kaolin should be 5% rather than more than 7%.
A novel method for 3D reconstruction of blood vessels
Authors: Lu Shengyu
Published: January 2021

With the development of computer technology, computer-aided diagnosis has been greatly improved. Computer-aided diagnosis can help doctors diagnose with medical imaging and other technique. Cardiovascular disease(CVD) lead to death with high probability. The computer-aided toward blood vessel is necessary. In this paper, we propose a novel method for 3D reconstructing of blood vessels. We calculate the volume data of blood vessels using an implicit modeling method based on the scanned blood vessel images, and establish a 3D model for blood vessels. Compared with existing methods, our method can obtain the surface and internal information of blood vessels accurately based on the implicit function method. The experimental results reflect that our method can implement 3D reconstruction of blood vessels with high accuracy and smoothness.
Cellular response of biodegradable AZ31 magnesium alloy stent in artery
Authors: Wang Na , Li Kun , Zou Yongyan , Wang Jinguo
Published: January 2021

Because of the increasing incidence of coronary artery disease, the use of cardiovascular stents is gradually increasing. In percutaneous coronary intervention, advantage of bioresorbable stent is that the stent does not remain in the human body after completing the necessary mechanical support to ensure the blood vessel open, and finally degrades into harmless molecules. Compared with bare stents, which require long-term retention in the body, the incidence of restenosis in stent or late stent thrombosis was lower. Current biodegradable stent mainly include polymers, biodegradable stents and metal alloy stent. Magnesium-based stent degradation and its copolymers are used in the application of biological absorbable stents and attract the attention of researchers.
Application of Plasma Ignition in the Middle Storage-Type Lean Coal-fired Boiler
Authors: Lu Xiao , Wang Chaoyang , Du Jianqiao , Yan Xiaopei , Ma Hui , Jia Yonghui , Shi Yang
Published: January 2021

The paper introduces the realization process of a plasma burner in a middle storage-type lean coal-fired boiler from the aspects of cold leveling test, relevant logic optimization, cold pulverizing method, online monitoring of relevant parameters of the pulverized-coal feeding system and combustion adjustment and proposes corresponding measures for some problems in the plasma burner arising during adjustment. In the case of appropriate coal quality, the successful application of plasma in key links like steam blowing, air-cooled island hot flushing, and no-load test has saved a lot of fuel, presenting a good economic efficiency.
Detection of initial strain of main ribs of concrete beam (or slab) by bending moment increment method
Authors: Cheng Bo , Jiang Liping
Published: January 2021

In the inspection and identification of engineering structures, it is often necessary to understand the force state of the main ribs of the components. Based on the structural performance test, the relationship between the bending moment of the concrete beam (or slab) in the elastic phase and the plastic phase and the strain of the main rib is analyzed. The initial moment of the main beam of the concrete beam (or slab) is proposed by the bending moment increment method. By adding a small amount of bending moment and measuring the strain increment of the main rib, the initial strain of the main rib of the flexural member is estimated to better understand the structural performance of the member. During the bending moment increment detection process, the increase in bending moment is small and does not adversely affect the concrete structure.
Improving the Hot Corrosion Resistance of Nanostructured ZrO2-7wt.%Y2O3 Thermal Barrier Coatings Fabricated by Plasma Spraying
Authors: Wang Dongsheng
Published: January 2021

Conventional and nanostructured ZrO2-7wt.%Y2O3 thermal barrier coatings (TBCs) were prepared by plasma spraying technology. Microstructure and hot corrosion resistance of two TBCs in 75%Na2SO4+25%NaCl (mass fraction) mixed molten salt under 850 °C were compared. Meanwhile, hot corrosion failure mechanisms of TBCs were investigated. Results demonstrated that both conventional and nanostructured TBCs were typical lamellar stacking characteristic. However, compared with conventional TBC, the nanostructured TBC presented the base phase which is gained from recrystalization of fully melted nano-particles as well as the embedding phase of partially melted nano-particles. The nanostructured TBC has lower porosity and higher density. For both conventional and nanostructured TBCs, hot corrosion failure is caused by partial transformation of tetragonal phase (t-ZrO2) into monoclinic-phase (m-ZrO2) martensite as a response to the consumption of the stabilizer Y2O3. However, the nanostructured TBC generally has lower degree of hot corrosion and better protection to the metal bonding layer and matrix compared with conventional TBC.
Dried Biomacromolecule Nano-material Sampling and Characterization by AFM
Authors: Li Hongyu , Dong Chen , Wei Jiasi , Cai Xiaoyu
Published: January 2021

Nano-materials fabricated chemically or biologically are usually kept in liquid or solution. The characterization of these materials, especially about their dimensional scales, is important to the study of the materials as well as their further application. In this research, the dimensional features of a typical biomacromolecule nano-material are characterized by AFM in air mode and the uniformity is analyzed. Some dry samples are prepared for air mode measurement. The height of sample structure, h is (2.252±0.021) nm. The respective deviation of the overall structures’ heights and of the section heights in single structure is 0.023 nm, and 0.021 nm, which shows ideal homogeneity of the material and good uniformity of the structure.
Study on coal fly ash classified by bulk density
Authors: Feng Shuxia , Li Yanqi
Published: January 2021

As a major country with coal as its main energy source, China has great pressure on the production and reuse of coal fly ash. In this paper, three kinds of original low calcium fly ash from different regions were divided into five bulk density particle groups, < 1 g/cm3, 1-2 g/cm3, 2-2.5 g/cm3, 2.5-2.89 g/cm3 and > 2.98 g/cm3. The results showed that the bulk density of fly ash particles was mostly concentrated in 1-2.5 g/cm3. There were significant differences in the chemical composition and activity of the particle groups with different bulk density, but no consistent changes were observed. The correlation degree between acid oxide content and activity was significantly higher than that between bulk density and activity, indicating that acid oxide content had a significantly higher influence on activity than bulk density.
Characterization of Materials for Shape-memory and Biodegradable Ureteral Stent
Authors: Wang Na , Song Xuesong , Wang Jinguo , Hao Xiaomei
Published: January 2021

Ureteral stent is one of the commonly used instruments in urology, and its clinical efficacy is confirmed. However, there are also a series of complications or deficiencies, including infection after catheterization, formation of stent shell, and secondary endoscopy for tube extraction. The biodegradable ureteral stent can play the same role as the double-J tube, and it will be completely degraded after a certain time. The degradation fragments will be discharged with the urine, and the physiological functions of the ureter will not be affected. At the same time, there is no need to perform a second cystoscope for tube extraction. Therefore, patients do not have to undergo an invasive operation again, so as to alleviate the pain of patients and save time and cost.
Positioning Information System of Indoor Food Delivery Robot Based on UWB
Authors: Wu Peng , Wen Danli
Published: January 2021

In order to realize precise positioning with remote observation and control of the food delivery robot in the room. This paper designs a indoor robot positioning information system based on the DW1000 module and the network module of ESP8266. The improved TWR algorithm is used in the system to avoid the problem of clock out of sync among the base stations and improve the clock offset error of the base stations. The simplify Toa Algorithm makes the system locate quickly and accurately. At the same time, the wireless ethernet module ESP8266 is used to transmit the position data and the status information to the remote server which is easy to view the real-time position state and control the robot movement. The system is an embedded wireless interconnection system, which can satisfy the indoor robot positioning and information transmission, and realize the remote control of the robot.
Experimental study on the application of metamaterials in low frequency vibration reduction of thin plates
Authors: Li Hongwei , Wang Peng , Ren Weiwei
Published: January 2021

In order to validate the damping effect of metamaterials, the low frequency damping effect of the spring oscillator metamaterials was used to test the vibration of thin plates. And the damping effect was compared with the viscoelastic damping materials. The results show that, with lighter additional weight, the low frequency damping effect of the spring oscillator metamaterials for plate was better than that of the viscoelastic damping materials.
Calibration of WLI Lateral Indication Error with 2D Micro/Nano Pitch Standard
Authors: Wei Jiasi , Sun Kaixin , Cai Xiaoyu
Published: January 2021

White light interferometer (WLI) is one of the common machines that are used to characterizing surface structures. The indication errors of WLI are key metrologic characteristics, which may affect evaluation result of WLI. In this paper, a two-dimensional micro/nano pitch (2D pitch) standard is introduced to calibrate the lateral indication error of WLI. The calibrating experiments are carried out in four measurement positions. The results and the uncertainty is anlysized. And the expanded uncertainty of WLI in lateral measurement (x50) is evaluated as tens of nanometer.
The Study of Multivariate Fuzzy Neural Scheme in Controlling Temperature during Beer Fermentation
Authors: Zhang Zhao , Zhou Qi
Published: January 2021

The brewery fermentation process has inherence characteristics of multivariable, seriously nonlinear, uncertain, time-variant and large delay. The given process parameters aren’t traced very well. In this paper, segmented control strategy is used, which is dividing the ferment process into pre-fermentation and post-fermentation period. In each ferment period, strategy of fuzzy neural control based on Multivariate –decoupling is adopted and simulated in MATLAB, the results show the strategy’s validity and practicability in controlling beer ferment.
Study of shaking table substructure test loading by inertial mass
Authors: Ji Jinbao , Ding Zhen , Wang Chenguang
Published: January 2021

It is hardly to carry out large-scale shaking table test of entire structure for the high cost of model construction and the capability limited of shaking table in the field of civil seismic research. In this paper, a shaking table substructure test method loading by inertial mass was studied, and the inertial mass parameter was designed based on the principle of frequency equivalence. Numerical simulation was performed and the applicability of the test method was analysed. A shaking table test model of 5-stories steel frame model and the substructure test loading by inertial mass have been carried out. Result shows that the phase of the time history curves could in good agreement, but the peak responses of the substructure model were larger than the entire structure tests. So, the shaking table substructure test loading by inertial mass based on the principle of frequency equivalence is not suitable for the structure with uniform distribution of mass and stiffness. Finally, it has been verified that the substructure test based on the principle of frequency equivalence is suitable for the structures with large rigidity and concentrated mass by analysing of another example. The research of this paper could be referred for substructure test of large and complex structure.
A Case Study of Thoroughly Integrated STEM PBL Course of Mechanics
Authors: Guo Chong , Tang Yuehao
Published: January 2021

Along with the wide spread and deep penetration of STEM theory in China, the imperative task is to develop compatible courses with thorough interdisciplinary integration. The aim of this paper is to present a project-based learning (i.e., PBL) case study for college mechanics courses, in terms of the global structure, target analysis, activity design, comprehensive evaluation and implementation process. The features of this study can be summarized as follows. Firstly, in combination of students’ activity experience, the content of this study derived from a real-life problem truly realizes the interdisciplinary integration. Secondly, other than simply mixing the subject knowledge with hands-on skills, the objective of this study attaches specific importance to the stimulation of students’ interests and potentials in learning science and technology. Thirdly, the genuine research resources are adopted for implementing the project during the whole course. Fourthly, in order to urge students to form deep self-analysis, the course evaluation is composed of process and result assessments. In all, this study provides a reference for the development of an integrated STEM course. It may contribute to the acceleration of training professionals and construction of building innovation-oriented country.
Combustion synthesis of porous bismuth oxide
Authors: Wang Yajun , Li Shihui , Jiang Zisheng
Published: January 2021

Bismuth oxides with a micro porous structure were prepared by a simple combustion reaction between oxidizer (bismuth nitrate) and fuel (citric acid). These porous bismuth oxides were prepared at different values of the stoichiometric coefficient. The as-prepared products were characterized by X-ray diffraction (XRD), and scanning electron microscopy (SEM). The results show that many pores distributed in tetragonal bismuth oxides (β-Bi2O3) granules which have varied crystallinity and particle sizes at different oxidizer/fuel ratio. Increasing the fuel concentration improved the crystallinity and purity of β-Bi2O3. A further calcination could also increase the particle size, crystallinity and transform the phase structure from β-Bi2O3 to pure α-Bi2O3.
Analysis and Research on excavation deformation of deep foundation pit support engineering of metro station
Authors: Yuan Ye , Wang Yang
Published: January 2021

With the rapid economic and social development, the construction of urban underground rail transit is in full swing, and even many second and third tier cities are starting to build, In order to control the environmental impact of the excavation team and control the deformation, this paper takes a deep foundation pit project of a station in Wuhan Metro as the research object, combining with theoretical analysis, field monitoring and Midas GTS Nx numerical software simulation and other methods are used to discuss the ground settlement around the foundation pit, the impact on the adjacent bridge pile foundation, and the deformation control analysis.
Influencing factors analysis for algal blooms in cold region reservoir
Authors: Ashour Mohammed F. Y. , Guan Di , Zheng Guochen
Published: January 2021

This paper investigated the temporal variations of the phytoplankton biomass along 10 years in the Nierji reservoir located in the northeast of China. The factor analysis was applied to identify significant influencing factors of algal growth. The results demonstrated that total nitrogen (TN) was strongly correlated to phytoplankton in the middle of the reservoir and total phosphorus (TP) showed the same pattern in the outflow of the reservoir. In contrast, water transparency was weakly affected by the production of phytoplankton. Besides, there were annual variations observed for the ratios of TN to TP, while 54.02% of the collected data indicated that TP was limiting the phytoplankton.
Study on Degradation of Ureteral Stent Coated with Polycaprolactone Lactide
Authors: Wang Jinguo , Wang Na , Li Na , Han Wei
Published: January 2021

Ureteral stent has become a necessary consumptive device in the urinary system in the routine clinical practice. However, indwelled stent can cause complications such as hematuria, stone formation, and bladder irritation, et al. In recent years, the use of coating has become an important research direction to modify the surface of the stent and to reduce complications. In this paper, polycaprolactide lactide copolymer was used as coating material, uniformly coated the polymer on ureteral stent surface using solution impregnation method, so as to prepare ureteral stent with a certain coating thickness, and study the degradation behavior of coating in urine.
Analysis of Vibration Characteristics of Rotor Eccentricity for Generator in a Mobile Power Station
Authors: Li Xiaoquan , He Jiangjiang , Zhao Yuwei , Cheng Yuemeng
Published: January 2021

Due to machining accuracy, installation error and other factors, the rotor has various eccentricity, which will cause adverse effects on the operation of generator of certain mobile power station and even lead to all systems failure. In order to investigate the generator rotor’s vibration characteristics, taking a military mobile power station generator as the research object, a Jeffcott rotor model is established which considering rotor eccentricity with cubic term in this paper. It is consistent with the Duffing equation in any transverse motion equation. It is simplified to Duffing equation for solving. The analytical solution is solved by the Runge-Kutta method. By studying the effects of various types mechanical parameters on the transverse vibration, the rotor system’s main resonance is studied: the stiffness has extremely few effect on the amplitude change, however, the stability of the system changes greatly with them. While the amplitude only changes and the mass eccentricity reaches a certain value, the rotor system is prone to rub. Resonance amplitude, the response and phase of the system are all affected by the damping, therefore, damper is one of the most effective ways to suppress vibration of generator.
A Feedforward Decoupling Control Method for Multi-ports DC Transformer
Authors: Wu Hao
Published: January 2021

DC Transformer (DCT) is a new type of intelligent power electronic device using power semiconductors and high-frequency transformer to realize power conversion. Multi-ports DCT has broad applications in DC distribution networks. In this paper, the power transmission characteristics of the phase-shift controlled multi-ports DCT are analyzed. The non-linear coupling characteristics of the output power at different ports are also studied. The small-signal dynamic coupling model of the multi-ports DCT is established. On this basis, a feed-forward term is introduced and constructed in the closed-loop voltage control system. The theoretical analysis shows that the feedforward term can decouple the output voltage of different ports of the multi-ports DCT. The correctness of the feed-forward control method is verified by simulations.
Research on Non-intrusive Residential Electric Load Identification System Based on SOPC
Authors: Liang Yuzhe , Chen Hua , Xiang Qiang
Published: January 2021

The high-precision identification of the non-intrusive residential electrical load is an essential technology to realize the intelligentization of the power grid. Due to its low input cost and easy maintenance, this technology has received much attention at home and abroad. In order to improve the accuracy of load identification, this paper proposes a non-intrusive residential electric load monitoring equipment based on system on a programmable chip (SOPC), which is focused on hardware system design, characteristic parameters optimizing and BP neural network algorithm optimization. The feasibility of the system was verified by experimental simulation and tests. The results of experiment show that the method used for hardware design can not only improve the speed of system and most closely match the actual running state of electrical appliances in testing circumstances, but it can also realize the function of load identification rapidly and accurately under the condition of the given residential electricity.
Cause Analysis of Congested Pulverized Coal Dropping of Pulverized Coal Feeder in Storage Pulverizing System and Solutions
Authors: Wang Chaoyang , Lu Xiao , Du Jianqiao , Ma Hui , Jia Yonghui , Hao Qingzhe , Yan Xiaopei
Published: January 2021

The newly built unit in certain power generation company adopts storage pulverizing system and 16 sets impeller coal feeder. The pulverized coal feeders suffered unstable feeding frequently during infrastructure debugging, leading to large fluctuation of furnace negative pressure, steam temperature and load, and affecting safe and stable operation of the unit. This paper deeply analyzes the causes of congested feeding of pulverized coal feeder, formulates corresponding countermeasures from aspects of cleaning, installation and operation adjustment of pulverizing system, and guarantees stable operation of the unit through optimization logics and operation method. This paper provides references for actual operation and solution of similar problems in power plants.
Design of SOPC digital frequency meter based on MicroBlaze
Authors: Sun Haixin , Fan Yujie , Xiang Qiang
Published: January 2021

A method of SOPC implementation of digital frequency meter is presented in this paper. In the method, Encapsulated AXI IP core for frequency measurement and duty cycle measurement are configured with the embedded soft core MicroBlaze processor. The parameter measurement of the digital frequency meter is implemented by FPGA logic resources, and the measured data are transmitted to the soft core processor via AXI bus. The computation, control and display is completed by Microblaze soft core. The system is verified and tested on the Basys3 board card launched by digilent company. The results show that the system has the advantages of accurate measurement, good stability, simple scheme and low cost.
Gas-solid mixing characteristics of Geldart B particles in a fluidized bed with different height-to-diameter ratios
Authors: Xu Pengfei , Li Yixin , Wang Yujun , Liu Yan , Zhang Qingrui , Chang Guozhang
Published: January 2021

Under different height-to-diameter ratios (H/D), the gas-solid mixing characteristics in a fluidized bed filled with Geldart B were studied employing the Eulerian-Eulerian two-fluid model. Researches showed that with the H/D increased, the larger bubbles were generated and significantly affected the gas-solid mixing process. And at H/D=1.5, the radial particle velocity distribution had a relatively smaller fluctuation at different axial heights and a higher particle fluidization quality was obtained. Therefore, it can be concluded that under given conditions, a proper H/D is essential for obtaining a good gas-solid mixing in a fluidized bed.
Optimization analysis of air-conditioning duct structure of high-velocity train
Authors: Yang Fan , Liu Jianqiao , Han Pengfei , Li Ming
Published: January 2021

In order to improve the comfort of the air conditioning system in the driver’s cabin of a high-velocity train and advance the distribution of air supply, a 3D simulation software is used to establish the model of the air supply pipeline of the driver’s cabin. The air flow field and the rationality of the air distribution are analysed accordingly. The results indicate that the structure of the air supply pipe is optimized and the air flow rate in the left and right air chambers is solved and air flow rate in each outlet of the air supply pipe are achieved.
Research on Vehicle Control Strategy and Hardware in Loop for Pure Electric FSAE Vehicle
Authors: Zhang Ji , Lv Xiangjie , Lv Yu
Published: January 2021

As the environment protection and energy shortage drawing more and more attention, the development of new energy vehicle, especially electric vehicle has become an important tendency in vehicle industry. Affected by this trend, electric racing events has been held in Formula SAE (FSAE) in China since 2013. To achieve the testing of vehicle control strategy before debugging, enhance develop-efficiency, reduce the risk of vehicle debugging, this paper exploited a cost-effective, perfectly functional and easily operational HIL test platform for vehicle control unit. Firstly, this paper designed a reliable electrical system and safety circuit of vehicle according to racing rules, selected type of drive motor and high voltage battery pack. The software Cruise was used to simulate and check the correctness. After then, the vehicle control unit (VCU) including bottom drive module and control algorithm was built by means of rapid prototyping software development platform. Among this, the dynamic control algorithms as energy regeneration, yaw stability control in switching, and acceleration slip regulation were came up with and employed in the VCU aiming at the characteristics of racing car during contest. At last, the economical and applicable HIL system was studied and developed according to the need of vehicle control strategy testing. The joint simulation of Carsim and Simulink was used to check dynamic control algorithm. The HIL further verified vehicle control algorithm through loading program to VCU. The open-loop check to basically logic algorithm of VCU was conducted by setting component parameters and operating signal of driver in upper machine. The closed-loop test to control strategy of VCU was carried out through loading Simulink model of vehicle to TI 28335 development board.
Study on Design and Constructure of Offshore Substation
Authors: Huo Huanjie , Zhang Shi , Ren Shaoyi
Published: January 2021

In recently years, there are more than 70% of power generated by coal station. Based on this, it can be shown that fossil fuels are the main consumption for generating energy. Burning fossil fuels will produce a lot of carbon dioxide and other harmful gas. Moreover, fossil fuels are unsustainable energy, which means it will run out in the future. For avoiding this situation, sustainable energy need to be exploited so that can replace fossil fuels. Currently, there are wind power, solar power, nuclear power in China. Some wind farms already built in different place of China. Due to high advantages of sea, China is paying attention to develop offshore wind farm. This essay introduces details of offshore wind farm including rules of designing facilities and outlook of each level in China.
Analysis of the influence of virtual impedance on the stability of Parallel Voltage Inverters with Different Voltage Levels
Authors: Wang Jinmei , Ma Wentao , Miao Haidong
Published: January 2021

Using virtual impedance technology to optimize the double closed-loop control structure can improve the equivalent output impedance of the inverter to be inductive, improve the power distribution accuracy of traditional sensibility droop control strategy in low-voltage microgrid, and effectively restrain the circulation. But rarely consider the impact of virtual impedance on system stability. Therefore, Derive the transfer function of the three loop control structure including virtual impedance, line impedance and common point voltage, establish a parallel models of inverters with different voltage levels considering virtual complex impedance and simplify the model using Thevenin’s equivalent. According to the Nyquist stability criterion Analyze the effect of virtual impedance on system stability under various operating conditions. The analysis results show that the multi-inverter parallel system can maintain stable operation after adding the virtual impedance.
Research on Adaptability of Multi-model Kalman Filter in Integrated Navigation System
Authors: Mi Xiaolong , Zhao Wangyang , Zhang Guangtuo , Wang Xingling , Wang Yuanming
Published: January 2021

By applying multi-model adaptive control technology in data fusion of integrated navigation system, the multi-mode adaptive Kalman filter in the integrated navigation system is designed to overcome the problem of filtering accuracy reduction of inertial navigation system due to the changes in the external sensor status parameter with single mode Kalman filter model in the integrated navigation system. The simulation analysis is carried out on the system noise interference vector caused by the change of external environment and the change of the noise interference vector of measurement. The simulation results of a single model filter and the simulation results of multi-model adaptive filter are obtained. Based on the simulation results, it can be seen that compared with the single model Kalman filter, the multi-model adaptive filter is more accurate in the state error estimation of the system, and shows strong adaptability to the changes of the external environment.
Modeling and Forecasting of Wind Power Output of Urban Regional Energy Internet Based on Deep Learning
Authors: Weng Geping , Pei Chuanxun , Ren Jiaorong , Jiang Hao , Xu Jiayu , Zheng Weifeng , Liu Yuan , Gao Tian
Published: January 2021

Clean energy will account for a lot in the future energy structure with the emergence of Urban Regional Energy Internet. However, because of the intermittent and volatility of clean energy like wind energy, its main role in energy supply has restricted. Therefore, predicting wind power accurately is of great significance in the safe operation of the power system. In response to the above problems, this paper proposed a time series forecasting model of wind power based on BiLSTM, and analyzes the actual wind data in Urban Regional Energy Internet.