bluuebunny/crossref_metadata_2025 huggingface dataset:
Human Vehicle Dynamics Coupling of Miniature Electric Vehicle Roll Stability: Effects of Driver Weight, Wheel Base and Track Width
Authors: Luo Shuang
Published: August 2021

As a continuation of the previous research, influences of human vehicle dynamics coupling (HVDC) on miniature electric vehicle (MEV) roll stability are studied by varying driver weight, wheel base and track width. A multi-body dynamics model is developed for the human-vehicle system by ADAMS/Car software considering driver’s dynamics and is validated theoretically. Simulation results show that the MEV roll stability is decreased by the HVDC; the influences become greater with an increase in the proportion of the driver weight to curb weight of the MEV in both time and frequency domain; with the decrease of wheel base, the differences caused by the HVDC exhibit an increasing trend in the maximum value and overshoot; and the differences in the steady stable roll angle and phase lag at 0.6 Hz indicate an increasing tendency with the decrease of track width.
Study on Lubrication Performance of Composites Water-Lubricated Stern Bearing
Authors: Liu Changjiang , Gao Gengyuan , Gu Xiaomei , Zhang Fei
Published: August 2021

Stern bearings are the main supporting part of ship stern shafts. Water-lubricated stern bearings have the advantages of compact structure, easy maintenance, no waste and no pollution, and. Water-lubricated stern bearing materials are generally non-metallic materials, which are easy to produce elastic deformation when working. Based on this, fiber resin matrix composite materials are selected as water-lubricated stern bearing materials, and the Fluid-Structure interaction numerical method is used to research the lubrication performance of water-lubricated stern bearings, which is verified by the test with water-lubricated stern bearing rig. The effect of rotating speed on the performance of water-lubricated stern bearing under different loads is studied in this paper. The results provide technical and theoretical basis for the study of water-lubricated stern bearings.
Mechanical System Design and Motion Space Analysis For Transmission Line Insulators Laser Deicing Robot
Authors: Niu Jie , Jiang Wei , Zou Dehua , Kuang Jianghua , Liu Lanlan , Qiao Xiaoguang
Published: August 2021

In the cold winter, it is a routine task to deicing on transmission lines in severe cold climate so as to ensure the safety and stable operation of transmission lines. Compared with the traditional contact deicing method for transmission line insulators, the using of laser for transmission line deicing has the advantages of sound deicing effect, no damage to the lines, clean and efficient energy utilization, et al. As the laser energy gradually decays with the increase of distance, this paper proposes a new method to realize laser deicing of short-range transmission line insulator by using UAV equipped with laser. In responds to the dispersion problem of traditional control, this paper fully integrates U AV control and laser control platform, the double have been integrated into one, in the new control platform, the U AV control and laser control can be realized simultaneously, the kinematics model of the laser has been established and its forward and inverse solutions have been solved and analyzed. Finally, simulation experiments verify the validity of the model. Compared with the traditional mode, this deicing mode not only realizes the control integration, but also it is easy to operate. It is especially suitable for the operation in the transmission line field environment, which greatly enhances the robot operation efficiency. At the same time, the simulation of laser head sweeping space and deicing operation motion planning based on the kinematic model show that the system designed in this paper can realize the suspension insulators deicing without blind area. The implementation and promotion of this study has important theoretical significance and practical application value for the practicability of intelligent operation and transmission lines maintenance management.
A Contact Model of Heterogeneous Material by Method of Images
Authors: Li Jianglin , Chen Nan , Li Pu , Jin Xiaoqing
Published: August 2021

Contact analyses of heterogeneous materials may find crucial applications in many tribological studies. However, the simulations of such analyses may be difficult to be implemented since the nonlinear behaviors caused by the material heterogeneity and contact may be more complicated. Based on Eshelby’s equivalent inclusion method (EIM), an arbitrarily shaped inhomogeneity interacting with a contact load may be evaluated by an equivalent inclusion model with a contact load, where the influences of the boundary surface are taken into account through the method of images. In order to improve the computational efficiency, a two-dimensional fast Fourier transform based algorithms (2D-FFT) with zero padding and wrap-around order are employed to solve the contact problem. To benchmark the present solutions, an elastic half-space containing inhomogeneities under Hertzian-type contact load is considered, and parametric studies are further performed to demonstrate the effects of elastic modulus and depth on the stress field.
A Numerical Study of Oil Cavitation in a Refueling Pipe
Authors: Liu Nan , Shao Weiguang , Yang Ye , Yin Haojie , He Qiyang
Published: August 2021

The issue of cavitation of oil in a pipe is a concerning problem in the design of a high-speed refueling device. This paper established a CFD model for the fluid flow of oil in a refueling pipe based on FLUENT and applied a combined VOF multiphase model and Schnerr-Sauer cavitation model to simulate the cavitation behavior as the oil flows around obstacles in a pipe. The effects of refueling speed, obstacle structure, and pipe diameter on the cavitation were numerically studied using the combined model, and the volume and mass rates of cavitation and their distribution characteristics were obtained. The numerical results show that: the cavitation is strong behind the obstacle, which presents a length of 217 mm, maximum volume rate 53%, and maximum mass rate 0.18% as the refueling speed is 10 m/s; reducing the inlet velocity and increasing the pipe diameter can dramatically weaken the cavitation behavior; adding more obstacles leads the cavitation area reduces first and then keep stable gradually, in which the cavitation phenomenon starts from the first obstacle; placing the obstacles alternatively in the pipe can significantly intensify the cavitation, while the cavitation always starts from the last obstacle.
Process Analysis of Fragment Penetrating Natural Rubber Material
Authors: Hong Dou , Li Wenbin , Zheng Yu , Jiang Ning , Pu Bo
Published: August 2021

The anti penetration characteristics of natural rubber and the influence of fragment velocity on penetration energy were studied. Through the experimental study, the ultimate penetration velocity of different diameter fragments penetrating different thickness rubber target is obtained, and the penetration process is analyzed. The damage characteristics of target are explained through different stages of penetration. At the same time, the influence law of different residual velocity on the expansion velocity of rubber fragment cloud behind target is obtained, the energy required for the fragments to penetrate the target and the expansion velocity of the fragments after the target will increase with the increase of the fragments’ entry velocity.
Harmonic Component Analysis of Mode Shapes for Packeted Bladed Disk
Authors: Wang Rui , Xu Zili , Luo Jian , Lv Hongshui
Published: August 2021

Vibration characteristics of packeted bladed disk is complicated. To study the vibration characteristics of the governing stage bladed disk of 660mw steam turbine, cyclic symmetry method is used to calculate the mode shapes. Fourier transformation of vibration distribution in the tangential and axial direction along the circumferential of the bladed disk is applied to obtain the harmonic components. It is found that the Fourier decomposition of each blade displacement contains not only unique component, but also other components. For integrally shrouded blades, the resonance of the m nodal diameter mode can be obtained only when the corresponding natural frequency satisfies the condition ωn
= kn = mn, where n is the rotational speed and m is the harmonic number. For packeted bladed disk, there are additional harmonics that resonance occurs. The harmonic components are related to the nodal diameter number when the number of blades groups and the total number of blades are given. The diagrammatic method is applied to predict the wavenumbers present in modulated eigenfunctions.
Deformation and Fracture Behaviors in Microscale Laser Dynamic Flexible Forming: The Case of Fabricating Micro-Channel on Copper Foil
Authors: Chen Songling , Shen Zongbao
Published: August 2021

The case of fabricating micro-channel on copper foil using micro-scale laser dynamic flexible forming (μLDFF) is investigated in this work. To study the deformation and fracture behaviors, the copper foils are subjected to increasing laser power density until the occurrence of fracture. When laser power density ranges from 0.110 GW/cm2 to 0.441 GW/cm2, smooth micro-channel features are formed on copper foils, and the depth of the micro-channel gradually increases. Melting marks are observed at the micro-die entrance of the sample with 0.441 GW/cm2 laser power density. When laser power density is 0.544 GW/cm2, partial fractures are observed. The surface of fracture region is rougher than that of micro-cracks and no micro-cracks regions, which is caused by the higher strain in fracture region. And the fracture edge is irregular, which is caused by the soft effect of material. Complete fracture occurs when laser power density is 0.691 GW/cm2.
A Novel A-CNN Method for TBM Utilization Factor Estimation
Authors: Yu Honggan , Tao Jianfeng , Qin Chengjin , Sun Hao , Liu Chengliang
Published: August 2021

Utilization factor is one of the most important performance indicators of TBM, which affects the construction period and cost of the tunnel. However, there are few models to evaluate the utilization factor based on geological conditions and operational parameters. In this paper, a novel A-CNN neural network architecture for TBM utilization factor estimation is proposed. Firstly, the input dimension is expanded by a full-connected neural network. Secondly, a convolutional neural network is designed and added behind the expanded input to extract relevant features. Finally, a regressor is designed to build the mapping relationship between the extracted features and the utilization factor. The data collected from a Singapore tunnel project was utilized to verify the proposed method. The results show that the R2 of the proposed method on the test set is 0.521, which is 52.33%, 15.60%, 34.10%, and 9.40% higher than the KNN-based, SVR-based, RF-based, and DNN-based methods, respectively. Therefore, the proposed method can estimate the TBM utilization factor more accurately.
Investigating into Deep Neural Networks for Applicable Hard-hat Wearing Detection in Substations
Authors: Li Tong , Chen Qipeng , Gan Jinrui , Wu Peng
Published: August 2021

All staffs are strictly requested to wear hard-hats when working in substations. Various object detection algorithms, especially those based on deep learning, thus have been proposed for the corresponding purpose. A deep learning based-object detection algorithm commonly involves a fundamental neural network which dominates detection performances, so this paper investigates different types of networks’ applicability when utilizing them with a typical object detection algorithm for the monitoring of hard-hat wearing in substations. This is conducted from various perspectives concerned by real-world implementation that includes time consumption, computation speed, precision and more. As a consequence, this study provides a guideline to the selection of the most appropriate deep neural network architectures for the specific monitoring scenario.
Simulation Study on Bearing Capacity of Timber Beams with a Large Longitudinal Crack
Authors: Hu Xiaoyi
Published: August 2021

In order to investigate the influence of longitudinal cracks on the bearing capacity of wood beams, the simulation models of cantilever beam and simply supported beam with cracks were established based on the FEM and XFEM. Through the simulation, influence of the cracks on stress distribution and bearing capacity of the beams are discussed. Simulation results show that longitudinal crack has an effect of homogenizing the stress field in the wood beam, which is helpful to improve the overall displacement bearing capacity of the beam. Considering that survival with injuries is the normal state of wooden structures, the damage tolerance theory of wood structure can be developed. Therefore, this paper is a preliminary attempt in this field. However, the more complex microstructure of wood will make the damage process more complex. In the future, it is necessary to carry out targeted research, which can not only establish the damage tolerance theory for wood components, but also inspire more in-depth thinking and research in bionics.
Analysis and Application on Inverted Arch Support of Cross-cut Floor Heave
Authors: Wang Chao , Wu Yongping , Chen Shijiang , Zheng Wenxiang , Chen Xiaoyi , Nan Tongxin , Zhao Zihao , Duan Xiaobo , Li Qing , Zhang Bo
Published: August 2021

The cross-cut is an important gateway to connect the main roadway and the coal seam. The transportation, the pedestrian and the ventilation of mine could be seriously influenced by floor heave of cross-cut. Aiming at the severe floor heave of +1100 m track cross-cut in Liu Yuan Zi Coal Mine, the cross-cut surrounded with hard roof and soft floor was found. To solve this problem, the bolt-net-shotcrete and 36U-shape steel combined supporting (the original supporting scheme) and the bolt-net-shotcrete and 36U-shape steel round shed combined supporting (the new supporting scheme) respectively were applied to the cross-cut by numerical analysis. The simulation results indicate that the floor heaves is reduced by 57%, and the surrounding rock stress was changed from tension to compression at the bottom and the plastic range decreased and trended to homogenization. Field application results indicat that the cross-cut floor heave can be controlled effectively by bolt-net-shotcrete and 36U-shape steel round shed combined supporting. The conclusions provide a reliable technical scheme for hard roof and soft floor roadway.
Determination of Parameters of Johnson-Holmquist-II (JH-2) Constitutive Model for Red Sandstone
Authors: Huang Hongxin , Li Wenbin , Lu Zhenyu
Published: August 2021

In this paper, the parameters of Johnson-Holmquist II (JH-2) model of red sandstone are determined. Firstly, some mechanical properties of red sandstone specimens are tested, including quasi-static compression, SHPB dynamic compression test and Brazilian disk splitting test, and the basic mechanical parameters are obtained. Then, according to the theoretical model of JH-2 and other supplementary literature, some material parameters are preliminarily determined. Finally, by comparing the numerical simulation results with the experimental results, satisfactory parameters are obtained, which can effectively and accurately describe the mechanical response of red sandstone at various stages.
Research on Carbon Sequestration of Building
Authors: Shi Yu , Fu Yi , Chen Zongsheng , Shi Tiemao , Chu Yaqi
Published: August 2021

This paper briefly introduces the background, theory and recent achievements of building carbon sequestration, and introduces in details of the calculation method and the research characteristics, operability and shortcomings of this method. It points out that the model has conceptual visualization, rich connotation and its role in the design of low-carbon urban space, and its influence factors on the layout of low-carbon space are obtained from the determination of coupling building carbon sequestration according to the area of building units and patches. Finally, the current research trends and methods are reviewed and prospected, and it points out that its the whole life cycle and multi-scale and multi-objective influence mechanism can play a guiding role in the spatial layout of low-carbon cities.
CEPC’s Features and Expectation for the Future
Authors: Shao Yilang
Published: August 2021

This report will briefly introduce the CEPC and its booster and collider, which are the main components of CEPC. To get a more accurate physical model of the universe, CEPC has been enhanced in many design aspects and will outperform the original LHC in many aspects. CEPC will also help scientists discover many unanswered questions, such as dark matter, and it will focus on electroweak physics. CEPC has a strong potential in high-energy physics and the scientific community as a whole.
Research about a fast identification method for intermittent single Sub-synchronous Resonance phenomenon in large scale doubly-fed wind farm
Authors: Yuan Ye , Zhu Daming , Shi Qiaofan , Wang Kai , Feng Shitao
Published: August 2021

In this paper, a synchronous resonance (SSR) phenomenon caused by a large scale doubly-fed wind farm group after putting in series compensation device is analysed. By analysing the changing trends of the indicators during period of SSR phenomenon, 11 power quality indicators are chosen for calculated, then divided all the 11 indicators into 3 source data and 8 preliminary stage operational data by the observability of value. After divided the two kinds of data, a Pearson correlation coefficient between this two kind data was calculated to judge the relationship of them, and the characteristic indexes with stronger correlation during the resonance period were analysed. The maximum value of the above 8 characteristic indexes in the normal power generation process is used as the basic data for comparison, so as to realize the rapid and accurate judgement of the SSR moment. In the process of SSR judgement, the method has the characteristics of faster speed and simple determination, and it does not need to reform the existing power quality online monitoring device, and can realize real-time analysis and judgement of SSR phenomenon only by increasing extraction of the existing data function from the monitoring system. Finally, by testing data of two actual SSR events, the characteristic index determination method proposed in this paper is analysed and verified, and the feasibility of this method is proved.
Research on Nuclear Post-accident Liquid Level Detection Signal Deviation in Nuclear Power Plant Reactor Building
Authors: Fu Jiang , Jiang Jianjun , Yi Meng , Guo Chuan , Tang Lei , Han Yang
Published: August 2021

The level meter in the containment of nuclear power plant adopts the principle of static pressure measurement, and the pressure guiding medium is silicon oil, which is used to continuously measure the level of circulating coolant in the containment under the nuclear accident status and post-accident, aimed at the problem of serious deviations in measurement results caused by large changes in the density and volume of silicone oil affected by temperature changes, a detailed analysis of the root cause of the problem occurred, and the serious consequences that may arise will be described, proposed three solutions, analysed and demonstrated the feasibility of the three options and whether they meet the requirements of operating personnel to monitor the circulating cooling liquid level under the nuclear accident status and post-accident, after comprehensive analysis and comparison, the solution was finally determined. The results show that, according to the requirements of the measurement environment temperature range, selecting 85 degrees as the environment temperature for instrument calibration can minimize the measurement error, which is beneficial for the operators to monitor the circulating coolant level in the containment under the nuclear accident status and post-accident, meet the application requirements.
Prediction of photovoltaic power generation based on Bayesian neural network with grey correlation
Authors: Zhu Jiaxiong , Xiao Zhigang , Feng CHANG
Published: August 2021

Photovoltaic power generation depends on weather conditions, which has the characteristics of randomness, volatility and intermittence. In order to ensure the security and stability of the grid connected process and make full use of the advantages of photovoltaic power generation, this paper proposes Bayesian optimization algorithm based on grey correlation to predict the power of photovoltaic power generation. The gray correlation selects the similar correlation data from the original data set, and normalizes the data sample set to eliminate the influence of data size caused by different data dimensions. Bayesian optimization algorithm can effectively prevent over fitting by adding regularization term and super parameter α, β. Experiments show that the photovoltaic power prediction method based on Bayesian optimization algorithm under grey correlation has higher accuracy and robustness, and can provide more comprehensive information for power grid dispatching and control.
Research on Three Phase Signal Separation Method and Device for Live Detection of Circuit Breaker Contact Ablation Degree
Authors: Wang Chao , Wang Jianlong , Sun Dong , Dong Sichen , Yang Jie , Gao Jinyu , Wang Hongxing
Published: August 2021

A three-phase identification method and device for live detection of arc extinguishing performance of circuit breaker are proposed. In this paper, a sensor with three antennas is used to detect the electromagnetic wave radiated by the circuit breaker, and the three-phase identification is realized by controlling the receiving angle of the antenna and comparing the amplitude of the received electromagnetic wave. The method proposed in this paper has the technical advantages of simple implementation and low cost of detection device, and can realize the three-phase identification of live detection of circuit breaker arc extinguishing performance.
Comprehensive Evaluation of Weapon Equipment Systems Operational Effectiveness Based on State Space Concept
Authors: He Zhixing , Zhao Lijun , Ge Lin , Tang Qiaoqi
Published: August 2021

In recent years, there are many researches on combat test of weapon equipment systems. However, in the process of comprehensive effectiveness evaluation, there are some shortcomings in the construction of index system, such as index redundancy, experts subjective weighting, which lead to the lack of objectivity and scientificity. Focusing on the objective state of the evaluated object, this paper puts forward an idea of comprehensive evaluation in the efficiency state space (ESS), and uses intelligent data processing method based on principal component analysis to examine the correlation of the underlying indicators of the evaluation index system (EIS), and attempts to conduct a comprehensive evaluation on this basis. Finally, we give the comparison the corresponding new results with the original evaluation results in the references. The data show that comprehensive evaluation under ESS can reduce efficiency calculation dimension from10 to 3. The final efficiency ranking is slightly different from that in the reference, but is much more rational and convincing.
Design of Mine Temperature Measurement System
Authors: Chenyu Dai
Published: August 2021

This paper introduced a method of mine temperature measurement. The system used PT100 temperature sensor as sensing unit, constant current source composed of operational amplifier as excitation source, amplification circuit and A / D conversion circuit to process the output signal of Pt100 sensor, and STM32F103 microprocessor was used for data calculation and display, and the temperature data was converted into a 485 signal for long-distance transmission and temperature measurement system. The experimental results show that the system has high temperature measurement accuracy, wide measurement range, and low cost. Reliable measurement of temperature parameters in coal mines can be carried out, which is of great significance to ensure coal mine safety production.
Design and Implementation of a Wireless Iidentification Device
Authors: Lv Meimei , Ou GuoFeng , Ma Yan
Published: August 2021

This system takes AT89 series single-chip microcomputer as the core, which constitutes the two ends of the wireless identification device: transponder and reader. The whole system is mainly composed of the smallest single-chip microcomputer system, binary code preset circuit, carrier generation circuit, analog switch control circuit, high-frequency amplifying filter circuit, display circuit and other modules. The transponder part uses the AT89S51 single-chip microcomputer to control the serial output of the preset binary code, uses the active crystal oscillator to generate the carrier wave, and outputs the modulated signal through the analog switch. The reader part amplifies the modulated signal with high frequency, filters the signal, and controls the light-emitting diode to turn on and off to display the identification signal and the four-bit binary code after the acquisition and processing by the single-chip microcomputer. This design realizes the functions of identification, binary code preset and display, single power supply, transmission distance greater than 5cm, time less than 5s, accuracy rate greater than 80%, power less than 2W, transponder storage and other functions.
Research on Risk Assessment of Power Grid Based on Realtime Simulation System
Authors: Li Tong , Liu Jin
Published: August 2021

In order to ensure the safe and stable operation of the power system, the importance of power grid calculation in simulation analysis has become more and more prominent. It is particularly important to carry out power system hidden danger investigation and risk assessment for large power grids. This paper builds a "power system full-digital real-time simulation platform" based on ADPSS. Through the modeling of the actual power grid and full fault scanning, the existence and probability of risk, the scope and degree of loss are evaluated and measured, and the operation of the power grid is analyzed. The safety and stability of the power grid, while identifying weak links in the power grid. This assessment method can provide technical support for the investigation and management of hidden dangers in the power grid, and has certain practical significance and positive guidance for the stable operation of the power grid.
Risk Assessment of Power Systems Dispatching Decision Considering Photovoltaic Systems Penetration
Authors: Yin Rui , Shi Min , Wang Tieqiang , Yan Peng , Wang Yifeng
Published: August 2021

Grid-connected photovoltaic power generation is an important form of new energy utilization, which can effectively reduce the dependence of power system on traditional energy sources. However, the randomness and uncertainty of the output of photovoltaic power generation system will also pose some risks to power grid dispatching decision-making. The source of dispatching decision risk is analyzed, and a risk index system including line overload risk, reserve shortage risk, load shedding risk and light abandonment risk is established. Then a risk assessment model for optimal dispatch of grid-connected photovoltaic power generation is established. The time of power flow calculation is greatly simplified by using power flow distribution factor. Finally, through the risk assessment of IEEE RTS-79 system scheduling decision-making, the risk of scheduling decision-making under different photovoltaic acceptance is analyzed, and the feasibility of the model is verified.
Research on the Ventilation System Valve Control and Power Distribution of a Nuclear Power Plant Conventional Island
Authors: Shao Jiaye , Li Li , Song Ze
Published: August 2021

The conventional island ventilation system of a nuclear power plant has complicated types, numerous valves, and various control methods. These valves include electric valves and manual valves, and are connected to different control systems. Therefore, the control method and power distribution method of these valves are also different in each project. This article summarizes 8 control methods through classification and comparative analysis of these valves, and proposes 8 interface diagrams accordingly, standardizes the control and power distribution methods, and provides a basis for future engineering design and procurement.
Load Forecasting Mechanism of Electric Vehicle Based on FWA-BP
Authors: Wang Mingcai , Yang Ye , Peng Xiaofeng , Li Peijun , Li Shuaihua , Han Yingzhu , Liu Dunnan , Guo Weijia
Published: August 2021

The rapid development of electric vehicles and the popularization of related engineering applications require us to accurately predict the load of large-scale electric vehicles. In view of the current development status of electric vehicles, this paper first analyses the data basis and method selection of electric vehicle load forecasting. Then, a load forecasting method for large-scale electric vehicles based on FWA-BP is proposed, which fully considers the fluctuation characteristics of electric vehicles. Finally, the method proposed in this paper is verified by a simulation case, and the prediction results prove the effectiveness of the proposed method.
Design of Dynamic Simulation Software of Water Flooding Based on Unified Modeling Language
Authors: Pan Shaowei , Li Hui , Zhou Wei
Published: August 2021

The dynamic simulation software of water flooding is of great significance for observing the exploitation of crude oil and understanding the distribution of microscopic remaining oil in the underground reservoirs. Based on Unified Modeling Language (UML), the design of the dynamic simulation software of water flooding is completed. First, based on the results of demand analysis, the function module diagram of the software is established; then the use case diagram is designed to clarify the goals that the software needs to achieve; finally, the class diagram and the sequence diagram of the software are designed, which provides the basis for the specific coding implementation. The design of the dynamic simulation software of water flooding based on UML enriches and develops the theory, technology and method of exploitation geology, and promotes the further application of advanced computer technology in the petroleum industry.
Automatic Sensing and Measuring Technique for Power Metering
Authors: Feili Yang , Ke Zheng , Yingying Cheng , Xun Guo , Yuting Zhang
Published: August 2021

The growing demand for electricity has set higher requirements for the sensing and measurement system of smart distribution network. Therefore, a new state monitoring technology for power metering is proposed based on automatic sensing and measuring technique to improve power metering. Firstly, the influence of various physical conditions and natural environment is analyzed on power metering equipment. Then, internal detection is used to detect the operation state of the equipment. Secondly, DC (direct current) magnetic bias is detected by self-excited fluxgate. Furthermore, the working condition of the secondary circuit is tested by the secondary circuit current measurement method. Finally, the narrowband Internet of Things technology is adopted to conduct data communication with the terminal platform. The research results show that compared with the traditional online operation state detection and management system of smart distribution network, the innovative state monitoring technology can additionally monitor the temperature, DC magnetic bias and secondary circuit of the distribution network. This shows that improved monitoring technology based on automatic sensing and measuring technique can monitor the important state of the distribution network to reduce the risks caused by the inability to detect potential problems and improve the performance of the distribution network. The optimized state metering technology makes an example for the improvement of automatic sensing and measuring technique of the metering equipment of smart distribution network nationwide.
Intelligent Bird’s Nest Hazard Detection of Transmission Line based on RetinaNet Model
Authors: Hui Zhang , Jian Zhao , Yuran Chen , Su Jiang , Di Wang , Hao Du
Published: August 2021

Electric energy is a kind of secondary energy with clean and efficient, convenient and safe use and the most wide range of applications. The transmission line equipment and the bird's nest on the tower will adversely affect the transmission line equipment, and even endanger the reliable operation of the transmission line. At present, the traditional manual line patrol has the problems of heavy workload, high cost, low efficiency and many blind areas, and the classical machine learning algorithm for bird nest recognition and classification is relatively low in efficiency and accuracy. In order to solve this problem, the RetinaNet model based on deep convolution neural network is selected for automatic detection of bird's nest targets. By adjusting the appropriate network structure and parameters to optimize the model, a RetinaNet model suitable for bird nest detection is established. The experimental results show that the accuracy of RetinaNet is 94.1%, and the recognition speed of each image is 68ms. Compared with Faster R-CNN, YOLO and SSD methods, the validity and reliability of RetinaNet model for bird's nest detection on transmission line equipment and towers are verified.
AQI multi-point spatiotemporal prediction based on K-mean clustering and RNN-LSTM model
Authors: Zhu Jia , Li Baofeng , Chen Hong
Published: August 2021

The short term air quality index can usually be predicted by statistical and numerical methods, but for the multi-point prediction of AQI, the traditional methods are often inaccurate. In this paper, a new hybrid multi-point prediction method was proposed by combining K-means clustering with the circulating neural network long and short time memory (RNN-LSTM) model. Based on this prediction method, the air quality index in Dezhou was predicted 1-5 days in advance by using 28 multi-point pollution monitoring sensor data from January 1, 2018 solstice to August 31. The prediction results show that the model not only improves the accuracy and effectiveness of the prediction, but also reveals the relationship between land use patterns and air quality index (AQI), which provides important information for land use planning, air pollution mitigation and urban intelligent governance.
Optimal design of container heat dissipation safety based on five-block method and radial basis function
Authors: Liu Mengqi , He Xinpeng
Published: August 2021

The ability of the ocean to provide a good thermal environment and not take up land space resources has led to subsea data centres due to their energy efficiency, low failure rates and green sustainability. As a result, there is a growing need for subsea data centres to be structurally sound. This paper investigates the optimal design of data centre capacity and cooling structures to improve their thermal safety performance to a certain extent.

Firstly, the temperature quantification of the heat dissipation and heat generation processes is carried out using Newton’s cooling theorem and Fourier’s law of thermal conductivity to provide maximum and minimum constraints for optimization. Then, the " five-block method" is used to optimize the arrangement of internal servers with temperature constraints, considering the problem of packing same-sized items in closed spaces. Based on the quantification of the solid-liquid and solid-solid heat transfer processes and the local temperature analysis as well as the optimization of the boxing, the model yields a maximum of 384 servers for the data center.

Secondly, the fin structure is then further optimized for heat dissipation. An approximate model of the fin structure and thermal performance is developed and solved by a radial basis function (RBF) neural network algorithm. Then, based on 100 sets of parameters for the serrated fin structure, the RBF approximation model is used to optimize the range of values for height, pitch and thickness. Based on the three ranges of parameters, Monte Carlo simulations are used to generate different combinations of parameters for different shapes, and to obtain the exact parameter that will increase the surface area by 13.8%. In the case of the first task, a solution is obtained to store 396 servers.
Research on key technologies of 3D visualization of marine environmental field
Authors: Ma Huadong , Wang Ping , Wen Yubo , Yang Chenxi
Published: August 2021

In view of the slow rendering speed and poor effect of 3D visualization of marine environment field, this paper studies the 3D visualization of vector field and scalar field of marine environment based on particle system, second-order Euler integral algorithm, linear interpolation method and 3D GIS visualization technology. Firstly, the particle motion model is constructed based on the second-order Euler integration algorithm, and the multi-scale transformation model is constructed based on the perspective perception, and the multi-scale visualization model of the vector field of marine environment is established. Secondly, the mesh is generated by bilinear interpolation, and the color mapping model and the hierarchical color setting scalar field visualization model are established. Finally, based on the technology of 3D GIS, the 3D visualization of marine environment field is realized, and the rendering speed and rendering effect are improved, which provides the basis for the efficient utilization of marine environment information.
Method of extracting control points from GF-7 remote sensing image based on five-layer-fifteen-level tiles
Authors: Xiong Qiang , Fang Shenghui , Liu Xiaojuan
Published: August 2021

In view of the traditional manual and semi-automatic methods can not quickly and effectively extract control points, this paper uses five-layer fifteen-level tiles (FLFLT) as reference images, and proposes an efficient and automatic method for automatic extraction control points of GF-7 image. Firstly, the remote sensing image and reference image are sampled down, and the remote sensing image is partitioned to improve the image processing efficiency. The Harris algorithm is used to extract the feature points of the remote sensing image and reference image, the normalized cross-correlation (NCC) algorithm is used for feature matching, and the Random Sampling Consistent (RANSAC) algorithm is used for gross error elimination. Finally, the least-square algorithm was used to fit the geometric transformation parameters, and the geometric transformation model was used to carry out geometric correction of GF-7 image, and the better correction results were achieved. Experimental results show that the proposed algorithm can extract control points quickly and effectively, and can be used for automatic extraction and geometric correction of high resolution satellite data.
Analysis of the Train in Tunnel Paradox Based on Special Theory of Relativity
Authors: Wan Xiang
Published: August 2021

The train in tunnel paradox has always been a topic of debate in the scientific community, in order to allow readers to better understand its basic principles, and it needed to combine the basic knowledge of the theory of relativity to outline the train tunnel paradox. Taking Einstein’s special theory of relativity as the starting point of the argument, this paper elaborates on Einstein’s theory of relativity, focuses on the simultaneous relativity and the theory of physical motion shape change in the special theory of relativity, and clarifies the famous train in tunnel paradox. Based on the results of different reference systems, the author analyzes the paradox principle of trains and tunnels. Through the analysis, it can be seen that the special theory of relativity is meaningful in real life, and the learners should pay attention to the cultivation of their own logical reasoning ability when learning, and emphasize the understanding of the spirit of scientific criticism, so as to improve the learning effect of the special theory of relativity.
Effects of triphenyl phosphate (TPP) and nanosilica on the mechanical properties, thermal degradation of polymer nanocomposite materials and coating based on epoxy resin
Authors: Huynh Le Huy Cuong , Thanh An Truong , Bao Long Huynh
Published: August 2021

Epoxy resin DER 671X75 cured with hardener T31. Epoxy polymer composite materials DER 671X75/T31 were improved the mechanical properties, thermal stability by triphenyl phosphate (TPP) and nanosilica (fumed silica S5505). Triphenyl phosphate and nanosilica were dispersed in epoxy resin DER 671X75 by mechanical stirring and ultrasonic vibration. The structural morphology of materials was characterized by Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM). The thermal stability and thermal properties of materials were characterized by Thermo Gravimetric Analysis (TGA) and Differential Scanning Calorimetry (DSC). The results showed that triphenyl phosphate with a content of 5 wt % in epoxy resin DER 671X75 improved the mechanical properties of epoxy polymer coating film DER 671X75/T31 with an impact strength increased 25%. The contents of 5 wt % triphenyl phosphate and 1 wt % nanosilica in epoxy resin DER 671X75 improved the impact strength of epoxy polymer coating film DER 671X75/T31 by 125%. The thermal stability of epoxy nanocomposite materials DER 671X75/5% triphenyl phosphate/1% nanosilica/T31 increased 45.35%. Epoxy coatings based on epoxy resin DER 671X75/5% triphenyl phosphate/1% nanosilica/pigments/fillers/additives/hardener T31 achieved mechanical properties, physical chemistry properties for coating and, had thermal degradation over 500 °C.
Lifestyle Factors and Genetic Variants on 2 Biological Age Measures: Evidence From 94 443 Taiwan Biobank Participants
Authors: Lin Wan-Yu
Published: August 2021

Background

Biological age (BA) can be estimated by phenotypes and is useful for predicting life span and health span. Levine et al. proposed a PhenoAge and a BioAge to measure BA. Although there have been studies investigating the genetic predisposition to BA acceleration in Europeans, little has been known regarding this topic in Asians.

Methods

I have estimated PhenoAgeAccel (age-adjusted PhenoAge) and BioAgeAccel (age-adjusted BioAge) of 94 443 Taiwan Biobank (TWB) participants, wherein 25 460 TWB1 participants formed a discovery cohort and 68 983 TWB2 individuals constructed a replication cohort. Lifestyle factors and genetic variants associated with PhenoAgeAccel and BioAgeAccel were investigated through regression analysis and a genome-wide association study.

Results

A unit (kg/m2) increase of body mass index was associated with a 0.177-year PhenoAgeAccel (95% confidence interval [CI] = 0.163–0.191, p = 6.0 × 10–129) and 0.171-year BioAgeAccel (95% CI = 0.165–0.177, p = 0). Smokers on average had a 1.134-year PhenoAgeAccel (95% CI = 0.966–1.303, p = 1.3 × 10–39) compared with nonsmokers. Drinkers on average had a 0.640-year PhenoAgeAccel (95% CI = 0.433–0.847, p = 1.3 × 10–9) and 0.193-year BioAgeAccel (95% CI = 0.107–0.279, p = 1.1 × 10–5) relative to nondrinkers. A total of 11 and 4 single-nucleotide polymorphisms (SNPs) were associated with PhenoAgeAccel and BioAgeAccel (p < 5 × 10–8 in both TWB1 and TWB2), respectively.

Conclusions

A PhenoAgeAccel-associated SNP (rs1260326 in GCKR) and 2 BioAgeAccel-associated SNPs (rs7412 in APOE; rs16998073 near FGF5) were consistent with the finding from the UK Biobank. The lifestyle analysis shows that prevention from obesity, cigarette smoking, and alcohol consumption is associated with a slower rate of biological aging.
Excessive Pharmaceutical Pricing as an Abuse of Dominant Position – The Case of CD Pharma (Denmark)
Authors: Kianzad Behrang
Published: August 2021

On 31 January 2018, the Danish Competition and Consumer Authority adopted a decision1 finding the Swedish company generic distributor CD Pharma in breach of Art. 102(a) Treaty on the Functioning of the European Union (TFEU) by abusing its dominant position and having imposed excessive and unfair prices for the drug Syntocinon. The company increased the price of the drug by 2000% in the period April-October 2014 in the Danish pharmaceutical market. CD Pharma appealed to the Danish Competition Appeals Board,2 which on 29 November 2018 upheld the decision by the Authority. On subsequent appeal to the Danish Maritime and Commercial Court,3 the judgment by the previous court was upheld in a 3-2 decision on 2 March 2020, thus finding CD Pharma liable for infringement of Danish competition law as well as Art. 102(a) TFEU. The decision is final and not subject to further appeal. The case raises outstanding legal-economic issues regarding excessive pricing such as relevant market definition in pharmaceutical cases, the length of abuse, competitive price benchmarks, definition of economic value and the matter of dominance in public procurement and tenders. The case is rather unusual in that the alleged abusive period amounted to a six-month period, CD Pharma was the ‘losing’ party in the bidding process for the supply of the medicine in question, and CD Pharma subsequently had reduced prices through negotiations with the Danish central medicine procurer, Amgros. Similar to the Aspen Pharma decision4 by the Italian Competition Authority, where the Italian Medicine Agency (AIFA) reported the case to the Competition Authority, it was the Danish medicine procurer Amgros who had notified the Danish Competition and Consumer Authority about allegedly abusive practices. This subsequently led to an investigation and the adoption of the Decision. Following an introduction describing the Danish pharmaceutical market and specifics of the case, section two of this contribution details the proceedings at Danish Competition Authority. Section three depicts the proceedings at Competition Appeals Tribunal, and section four deals with the proceedings at the Maritime and Commercial Court. Section five concludes.
When More Is Still Not Enough: A Case of Ceftazidime-Avibactam Resistance in a Burn Patient
Authors: Herbin Shelbye R , Barber Katie E , Isaacson Andrew R , Dolman Heather S , McGee Jessica D , Baylor Alfred E , Tyburski James G , White Michael T , Faris Janie
Published: August 2021

Burn patients have numerous risk factors for multidrug-resistant organisms (MDROs) and altered pharmacokinetics, which both independently increase the risk of treatment failure. Data on appropriate antimicrobial dosing are limited in this population and therapeutic drug monitoring (TDM) for beta-lactams is impractical at most facilities. Technology is available that can detect genetic markers of resistance, but they are not all encompassing, and often require specialized facilities that can detect less common genetic markers. Newer antimicrobials can help combat MDROs, but additional resistance patterns may evolve during treatment. Considering drug shortages and antimicrobial formularies, clinicians must remain vigilant when treating infections. This case report describes the development of resistance to ceftazidime-avibactam in a burn patient. The patient was a 54-year-old burn victim with a 58% total body surface area (TBSA) thermal burn who underwent multiple courses of antibiotics for various Pseudomonal infections. The initial Pseudomonal wound infection was sensitive to cefepime, aminoglycosides, and meropenem. A subsequent resistant pseudomonal pneumonia was treated with ceftazidime-avibactam 2.5 g every 6 hours due to the elevated MIC to cefepime (16 mcg/mL) and meropenem (>8 mcg/mL). Although the patient improved over 7 days, the patient again spiked fevers and had increased white blood counts (WBC). Repeat blood cultures demonstrated a multidrug-resistant (MDR) Pseudomonas with a minimum inhibitory concentration (MIC) to ceftazidime-avibactam of 16 mcg/mL, which is above the Clinical and Laboratory Standards Institute (CLSI) breakpoint of 8 mcg/mL. At first, resistance was thought to have occurred due to inadequate dosing, but genetic work demonstrated multiple genes encoding beta-lactamases.