bluuebunny/crossref_metadata_2025_split huggingface dataset:
Research on the three-dimensional detection system of the rail full profile
Authors: Zhou Zhendong , Yang Haima , Liu Jin 
Published: September 2020

Abstract
To solve the problem of slow speed, low precision and low efficiency of manual measurement in the current inspection of rail. Based on the non-contact laser profilers, a three-dimensional detection system of the full profile of rail is proposed by using the integrated combination of four laser profilers. The top straightness of the rail is detected by two-point connection method and the bottom distortion of the rail is detected by the common-plane method. After field testing, the machine measurement accuracy of the rail height, rail head width, rail bottom width and rail waist width in both rail head and tail are 0.039, 0.037, 0.029, 0.036mm and 0.047, 0.037, 0.039, 0.042mm respectively; The distortion are 0.035 and 0.039mm respectively. Experiments show that the system can complete the measurement of rail efficiently and steadily, and improve the speed, accuracy and efficiency of measurement.
Ultra-low emission transformation of 600 MW supercritical circulating fluidized bed boilers unit
Authors: Xin Shengwei , Han Ping , Li Yingping , Zhang Peng , Duan Shoubao , Gan Zheng , Wang Hu , Du Jiajun , Hao Qianjun 
Published: September 2020

Abstract
With the introduction of ultra-low emission environmental protection policies in national and local coal-fired power plants, ultra-low emission transformation of coal-fired power plants is required to be carried out in an all-round way. Under this background, the first 600 MW supercritical circulating fluidized bed (SCCFB) boiler unit in the world have carried out the demonstration of the technical route of ultra-low emission transformation and the research of key technologies. By adopting limestone desulphurization and low nitrogen combustion in furnace, selective non-catalytic reduction (SNCR) technology outside furnace and the integrated desulfurization and dust removal process of flue gas circulating fluidized bed (CFB-FGD), the unit realizes the technical route of ultra-low emission, and has good investment and operation economy, which can adapt to the development trend of environmental protection in the future. The CFB-FGD and dust removal system can further improve the operation economy of the boiler by setting pre-electrostatic precipitator (pre-ESP), designing double-tower and optimizing the single-tower switching mode, optimizing the pressure margin of the induced draft fan, and adopting the coordinated desulphurization operation mode inside and outside the furnace. The research results can provide a reference for the selection of ultra-low emission transformation for 660MW ultra-supercritical CFB boiler unit.
Research on steel barrel flattened seam recognition based on machine vision
Authors: Niu Hao , Wu Bowen , Wang Qingyan , Zhu Zhisong 
Published: September 2020

Abstract
Aiming at the problems of low efficiency and poor accuracy in manually identifying the flattened weld seam. The method of combining machine vision technology with multi-thread and multi-process is proposed, and the detection and recognition system of flattened weld seam is designed. OTSU adaptive threshold algorithm combined with Canny operator edge detection method is used for image segmentation. The probabilistic Hough transform algorithm is used to extract straight lines to identify flattened weld seam. OpenCV function library and Python are used to implement image processing algorithm, and PyQt5 is used to design human-computer interface to monitor the status of weld seam detection in real time. Meanwhile, a processing pool for parallel processing of recognition algorithm is established, and Modbus communication and image acquisition are realized by multi-thread programming. The performance of multi-core CPU is fully utilized. The experimental results show that the system meets the design requirements, has the characteristics of small amount of calculation and accurate identification, improves the processing efficiency, and solves the practical production problems.
Strength check for production riser during dry tree unit coil tubing operations under different environmental conditions
Authors: Fu Fei , Yu Jianxing , Meng Zhanbin , Han Xiangxi 
Published: September 2020

Abstract
In this paper, we introduce the modelling, loads, result evaluation method and boundary for production riser strength analysis. We investigated the different result evaluation method and different boundary condition based on a real project. The strength checks for the riser coil tubing stack up system in different environmental conditions was performed by SACS Software, calculate the most critical members UC and the maximum loads at critical flange locations of the riser during the whole dry tree unit coil tubing operations. According to the corresponding specification, the analysis results show that all the values of UC less than 1 and the project meet design requirements.
Effect of coupling weight of marine diesel engine on crankshaft vibration and lubrication
Authors: Wu Limin , Li Mei , Yang Ximin , Li Liting , Liang Gang , Qiao Xinqi 
Published: September 2020

Abstract
Journal misalignment caused by coupling weight result in rotary unbalance. To study the unbalanced effect, based on AVL EXCITE PU software, coupled multi-body dynamics and lubrication model of a marine diesel engine had been built, and validated by engine experimental data. Based on the simulation model, vibration and bearing lubrication of crankshaft with different rear-end configuration had been discussed. The results show that the unbalance caused by rear end coupling weight of crankshaft have effect on the 1st and 2nd main bearing near flywheel, and have little effect on other main bearings. It also changes the pressure distribution of upper and lower shell, and brings edge thermal load increase. Meanwhile, it has more effect on the heat transfer to shell than to journal.
Guidance for quadriceps rehabilitation based on AnyBody
Authors: Yu Shuting , Yao Ligang , Lu Zongxing , Cai Can 
Published: September 2020

Abstract
This paper aims to perform an objective quantitative analysis on quadriceps rehabilitation, and investigate the muscle status in cross-over design under rehabilitation actions. Rehabilitation actions are modeled using the human body modeling software AnyBody, which can analyze the variations in the muscle activity and muscle force of the quadriceps femoris during thigh flexion. In addition, it can experimentally validate the effectiveness of the model in combination with electromyographic (EMG) signals of three quadriceps femoris muscles during different activities. According to the study results, the rehabilitation actions of the quadriceps femoris can be quantified by means of collecting EMG signals.
Experimental study on the failure of tangential anti-loose dowel of ship hydraulic fluid tubing in alternating torque and vibration environment
Authors: Wu Ruliang , Huang Shouqing , Song Chao , He Wei 
Published: September 2020

Abstract
The internal hydraulic fluid tubing in central shaft is a critical part of pitch adjusting paddle in the ship propulsion system. The failure of screw pairs of internal hydraulic fluid tubing will result in a loss of propulsion. This real accident has happened on a ship. In order to determine the reason for the tangential anti-loose dowel falling out from the screw pairs, 380.5h and 147h alternating torque and vibration environment tests are completed on two samples with difference of manufacturing processing. The result shows that alternating torque and vibration combined stress is the synthesis stress for the dowel falling out from dowel hole. The basic reason is the larger fit clearance between dowel and dowel hole. This clearance is suggested to be manufactured below 0.2∽0.3mm, and the value of diameter for piercing outside the dowel hole should be greater than 1.95mm.
A method to calculate the life of sliding bearings based on fatigue and wear failure considering fluid lubrication
Authors: Guo Jiacheng , Huang Shouqing , Wu Ruliang , Ye Tianyuan , Chen Zhuo 
Published: September 2020

Abstract
In this paper, a sliding bearing is taken as the research object to study the life simulation and calculation under conditions of a certain eccentricity, a radius clearance, inlet and outlet pressures, a radial load, and taking into account fatigue and wear failure modes. For a calculation case when the eccentricity is 0.6, the average radius gap is 0.05 mm, the inlet pressure is 2 MPa, the outlet pressure is 0.1 MPa, and the radial load is 5000 N. The calculated fatigue life is infinite and the wear life is 7.1×104 revolutions. This paper focuses on providing a method for quantitatively estimating the life of sliding bearings.
Calculation and analysis on braided carbon/carbon composite pull-through fastener threads load distribution
Authors: Bian Tianya , Guo Wantao , Li Xiang 
Published: September 2020

Abstract
Braided carbon/carbon composites are widely used in the aerospace field due to their superior performance. However, because braided carbon/carbon composite materials have anisotropy characteristics, the distribution of screw loads in the fastener connection structure will differ from that of metal. In view of the particularity of the braided carbon/carbon composite fasteners’ connection, this paper obtains the theoretical results of the load distribution of screw teeth through the homogenization of stiffness and establishes a finite element model for comparative verification. The trend of finite element results is the same as that of theoretical calculation results which can provide guidance for the engineering design of carbon/carbon composite fastener.
Tool path active design for tooth modification of face-hobbed spiral bevel gears
Authors: Guo Wenchao , Mao Shimin , Yang Yu 
Published: September 2020

Abstract
An advanced design and manufacturing method called tool path active design for face-hobbed spiral bevel gears is mainly discussed in this paper. The method bases on the forming mechanism of extended epicycloids and utilizes an integrated cutter head without tilting, meanwhile, all its controlled parameters can be directly calculated according to the given meshing performances and modified conditions. Starting with the cutting principle of face-hobbing method, a tooth flank mending plan of altering tool path is developed, which detailed expressions are also given in functions. Then, the meshing performances which are used to determine the modification parameters are introduced and their formulas are also derived. Finally, the proposed method is validated by a numerical example of tooth contact analysis for a face-bobbed hypoid gear pair. As a further explanation, a numerical example of tooth contact analysis is done to validate the feasibility of the proposed method.
Analysis of 500kV composite insulator fracture fault
Authors: Liu Hui , Yang Tianshu , Zhou Chao , Jia Ran , Zhang Yang , Qi Zhao 
Published: September 2020

Abstract
This paper describes the fracture of composite insulator string of B phase on Tower 72 of 500kV line. A series of tests have been taken on the core rod and sheath to analyze the causation of the accident, including hydrophobicity test, dissection analysis, dye penetration, SEM and FTIR. It is found that the surface of the fault insulator is chalked, and its hydrophobicity is reduced. The interface between the epoxy resin matrix and silicone rubber sheath has completely failed. Epoxy resin matrix has been degraded, and partial discharge on the surface of core rod accelerates this process. The main chain of Si-O and side chain of Si-C in silicone rubber molecule are severely broken, and the surface of the umbrella is aging. It is concluded that the interface failure between sheath and core rod is the main cause of crisp fracture. Partial discharge at high voltage end and weak interface between glass fiber and epoxy resin matrix result in the development of degradation channels. Pollution and chalking on the surface of umbrella also explain part of the reason.
Research on 3D reconstruction technology of microscopic pore defects in cast steel
Authors: Yan Huadong , Zhou Xuewen 
Published: September 2020

Abstract
Affected by the production process, microscopic pore defects are inevitably distributed in steel castings. The existence of microscopic defects affects the macroscopic mechanical properties of steel castings. The numerical analysis of finite element model with microscopic pore defects is one of the effective ways to reveal the influence of microscopic defects on failure and fracture of steel castings. However, the spatial morphology of microscopic pore defects in cast steel is extremely complex, so the traditional CAE modeling method cannot meet the accuracy requirements. This article was inspired by the idea of reverse modeling in the medical field. Based on the 3D X-ray tomography data of G20Mn5N cast steel specimens, 3D models of microscopic pore defects with complex spatial morphology were reconstructed. Finite element analysis was performed in representative volume elements (RVE) model to study the effect of microscopic pore defects characteristics on the mechanical properties of cast steel.
Dynamic behavior analysis of radial hydraulically damped bushing based on FSI FEA method
Authors: Li Lin , Zeng Xiangkun , Feng Xiaolin 
Published: September 2020

Abstract
Nonlinear dynamic performances of hydraulically damped bushings (HDBs) can be characterized with two terms, dynamic stiffness and loss angle. In this paper, dynamic characteristics of a RHDB are estimated based on FSI FEA methods. Dynamic performances of the RHDB by FSI FEA method are precise. Obviously, FSI FEA method proposed in this paper can be effectively used to investigate and optimize dynamic characteristics of a RHDB, and also further to solve FSI problems of other component with hydraulic damping properties in the design stage.
Research on CIGRE benchmark model and improved DC control strategy
Authors: Yan Han , Liu Ke , Wang Xuan , Che Keshan , Ding Yujie , Yang Wenli 
Published: September 2020

Abstract
The safe and stable operation of the HVDC transmission system greatly depends on the control system. The DC control system realizes a series of control strategies such as constant-current, constant-voltage, and constant-extinction angle control by controlling the trigger phase. The CIGRE Benchmark model is often used as a standard test model for research, but it is usually necessary to improve in actual project. First of all, taking the CIGRE Benchmark model as the research object, the DC control mode and basic control functions are introduced systematically. On this basis, the improved control strategy is studied. At the same time, PSCAD / EMTDC simulation software is used to build an improved control system model. The transient response of CIGRE Benchmark and improved control system is simulated and analyzed. Furthermore, the control mode conversion and control system response under different control strategies are studied.
ISAR imaging and cross-range scaling of maneuvering targets using the scaled transform
Authors: Chen Jie , Pan Xiaogang , Xie Zhiming , Zhang Kunlun , Li Yaoyu 
Published: September 2020

Abstract
In this paper, a novel method based on the scaled transform is proposed for the ISAR imaging and cross-range scaling of a maneuvering target with uniform rotating acceleration. Firstly, the cross-range signals in each range cell can be modeled as multiple chirp signals. The scaled transform is utilized to eliminate the coupling with the slow time and lag time in the time-dependent autocorrelation function of multiple chirp signals. Then the 2-D accumulation plane can be obtained by the 2-D FFT and the cross-range profile can be obtained by a projection from the 2-D accumulation plane to the azimuth dimension. Meanwhile, the initial frequency and chirp rate of each scatterer can be estimated by the corresponding perk in the 2-D accumulation plane. Finally, the rotating motion parameters are estimated by the least square method and the cross-range scaling is performed. Simulation results prove the effectiveness of the proposed method.
Mixed Weibull distribution model of DC protection system based on entropy weight method
Authors: Wang Ting , Chen Kun , Zhang Kanjun , Du Zheng’an , Li Jun , Dai Di 
Published: September 2020

Abstract
By analyzing the blocking event of DC converter station of the State Grid Corporation in recently ten years, it can be concluded that the sampling system failure, secondary circuit fault, board fault, host fault, etc. of the protection system caused more than 10% of the DC system blockings, which have seriously threatened the normal operation of DC system. Towards this end, this paper makes a statistical analysis of the operation defects of high-voltage direct current (HVDC) transmission protection in Hubei Company in the past five years. A mixed Weibull distribution model method based on entropy weight method is proposed. By using this method, the reliability curve and average defect interval time (MTBF) of the DC protection system are obtained. Combined with the actual situation of the converter station, the DC protection system of the converter station is evaluated, which provides an important guiding basis for the subsequent maintenance, system transformation, and replacement of the converter station.
Single-pixel three-dimensional imaging for space-continuous targets based on compressive sensing
Authors: Wang Jing , An Yulong , Zhang Yanmei 
Published: September 2020

Abstract
In this paper, three-dimensional imaging method for space-continuous targets based on compressive sensing is investigated to get high precision imaging especially under low signal-to-noise ratio environments. Spatial correlation characteristic is adopted to enhance the anti-noise performance of imaging and the pulse echo attenuation characteristic is evaluated to settle the overlapping echo problem of space-continuous targets. Numerical simulations are performed to indicate the availability of our method and the experiment results demonstrate the applicability in 3D imaging, which is therefore fundamental to the complicated targets detecting and imaging with higher precision in the prospective practical applications.
Research on harmonic cooperative suppression strategy of hybrid parallel DC transmission system
Authors: Yan Han , Liu Ke , Wang Xuan , Che Keshan , Ding Yujie , Yang Wenli 
Published: September 2020

Abstract
Hybrid parallel DC transmission system has both flexible control characteristics of MMC-HVDC and large capacity transmission capacity of LCC-HVDC, which has good economy and practicability. However, the connection of hybrid parallel DC transmission system will bring a series of harmonic problems, so harmonic suppression measures must be taken. This paper firstly introduces the generation mechanism and basic characteristics of LCC-HVDC characteristic and non-characteristic harmonics. Then the causes of MMC-HVDC circulation are analysed. Finally, based on the parallel connection of LCC-HVDC and MMC-HVDC in the same AC bus, a harmonic co-suppression strategy of hybrid parallel DC transmission system is proposed and the simulation verification is carried out. The results show that the strategy can use MMC-HVDC to assist in absorbing the harmonics generated by LCC-HVDC.
Research on microwave heating structure optimization of auxiliary material box of road maintenance vehicle
Authors: Gao Kangping , Wei Xiaoyu , Jiao Shengjie , Li Jiabo , Wei Meng 
Published: September 2020

Abstract
The arrangement and spacing of microwave comprehensive maintenance vehicle antenna array directly affect the heating efficiency and heating uniformity of asphalt mixture. In order to improve the heating uniformity of asphalt mixture, this paper proposes a microwave heating structure based on auxiliary materials box, and optimizes the microwave heating structure of auxiliary materials box of road maintenance vehicle through CST simulation platform. Firstly, in the way of side-by-side arrangement of the antenna array, the spacing of the antenna array is optimized, and the heating uniformity of the asphalt mixture in the auxiliary material box is the best when the spacing is 132mm×155mm under side-by-side arrangement. Then, under the optimal arrangement spacing, the orthogonal arrangement of antenna array was put forward, and it was concluded that under this arrangement, the heating uniformity of asphalt mixture increased by 12.1%, and the proportion of asphalt mixture increased by 8.7% at 80°C -160°C. This conclusion has certain reference value to the improvement of the heating effect of the auxiliary material box heating system.
An obstacle avoidance design of UAV based on genetic algorithm
Authors: Hu Xusheng , Liu Juan 
Published: September 2020

Abstract
In order to improve the effect of obstacle avoidance, a PID control algorithm combined with genetic algorithm is proposed. By establishing the mathematical model of UAV, the auxiliary control system of UAV is analyzed, and then the control system is optimized by genetic algorithm. Taking STM32 as the control platform, the obstacle avoidance experiment was carried out by building the experimental platform. The experimental results show that the algorithm can avoid obstacles effectively.
High-precision spot positioning algorithm based on four-quadrant detector
Authors: Xiao Meifang , Zhang Yanmei , Li Huan 
Published: September 2020

Abstract
Inherent errors and random errors are consisting in four-quadrant detector when used for azimuth measurement. Many spot fitting algorithms are proposed to solve the inherent errors caused by the structure of the four-quadrant detector itself, which can reduce the errors in a way. In order to further improve the spot positioning accuracy and eliminate the influence caused by random errors such as background light and thermal noise, we first perform Kalman filtering on the output of the four quadrants when we perform experiments to calibrate parameters. Build an experimental platform, and experimentally verify that the Kalman filtering of the output of the four quadrants before bringing in the spot positioning algorithm can improve the accuracy of the composite fitting algorithm, thereby improving the positioning accuracy.
Wireless indoor localization using convolutional neural network
Authors: Qu Tianqi , Li Meng , Liang Dong 
Published: September 2020

Abstract
This paper provides a wireless localization method using convolutional neural networks (CNN) and based on WIFI fingerprinting data. We pre-processed WIFI fingerprinting data from Jaume I University public database and used it to train our CNN model. A WIFI fingerprint is composed of a series of received signals’ strength (RSS) released by many access points (APs). We changed the RSSs’ value at the edge of the signal disappearance. This operation can help the CNN model extract the features of fingerprints and have a better performance. After this operation, a CNN model can have about 21.2% lower loss and 23.5% higher accuracy than usual. Changing edge RSS is shown to be a good way to improve the performance of indoor localization.