bluuebunny/crossref_metadata_2025 huggingface dataset:
'We are not invincible': a qualitative study of self-care practices by Australian general practice registrars
Authors: Khan Nadia , Usherwood Tim
Published: September 2019

Doctors are not well known to look after their own health. The barriers and enablers that doctors face in staying healthy and managing ill health are not fully understood. This study aimed to explore these issues among general practice registrars (trainee general practitioners (GPs)). Semistructured interviews conducted with 14 GP registrars were audio-recorded, transcribed and analysed thematically. Participants noted the benefits of healthy lifestyle and the major barrier of competing priorities. Barriers to having their own GP included uncertainty about colleagues’ clinical abilities and about their respect for professional boundaries. Nearly all the participants had self-prescribed and many reported informal consultations with colleagues, although they noted the limitations of these. The participants identified their professional responsibility to maintain a healthy lifestyle and need for a regular GP, the importance of support for these responsibilities by training practices and regional training organisations and the value of training organisations incorporating such support into curriculum and policies.
Reflections on a community health elective in Native Hawaiian Health: a community-centred vision for health and the medical profession in Indigenous contexts
Authors: Hosaka Kalei R. J.
Published: September 2019

The medical profession is fundamentally thought of as a vocation and calling, one that requires the translation of knowledge and skill into counselling, diagnosis and interventions that benefit the lives of patients. Physicians and healthcare professionals have the immense privilege to compassionately use their vocation to improve the health of communities. What does this commitment look like in an Indigenous health setting? Using the author’s own experience as a participant–observer in the University of Hawaii’s John A. Burns School of Medicine’s Native Hawaiian Health elective, an example is provided of an educational curriculum that seeks to integrate community health in Native Hawaiian settings. This paper shows the ways that the author’s understanding of health broadened to include environmental stewardship and healthcare professionals’ compassion and involvement in the life of the community throughout the elective. By providing this example, the author seeks to shed light on how a medical education initiative can change the way students approach Indigenous health.
Advancing vaccine development for gonorrhoea and the Global STI Vaccine Roadmap
Authors: Gottlieb Sami L. , Jerse Ann E. , Delany-Moretlwe Sinead , Deal Carolyn , Giersing Birgitte K.
Published: September 2019

Efforts to develop vaccines against Neisseria gonorrhoeae have become increasingly important, given the rising threat of gonococcal antimicrobial resistance (AMR). Recent data suggest vaccines for gonorrhoea are biologically feasible; in particular, epidemiological evidence shows that vaccines against a closely related pathogen, serogroup B Neisseria meningitidis outer membrane vesicle (OMV) vaccines, may reduce gonorrhoea incidence. Vaccine candidates using several approaches are currently in preclinical development, including meningococcal and gonococcal OMV vaccines, a lipooligosaccharide epitope and purified protein subunit vaccines. The Global STI Vaccine Roadmap provides action steps to build on this technical momentum and advance gonococcal vaccine development. Better quantifying the magnitude of gonorrhoea-associated disease burden, for outcomes like infertility, and modelling the predicted role of gonococcal vaccines in addressing AMR will be essential for building a full public health value proposition, which can justify investment and help with decision making about future vaccine policy and programs. Efforts are underway to gain consensus on gonorrhoea vaccine target populations, implementation strategies and other preferred product characteristics that would make these vaccines suitable for use in low- and middle-income, as well as high-income, contexts. Addressing these epidemiological, programmatic and policy considerations in parallel to advancing research and development, including direct assessment of the ability of meningococcal B OMV vaccines to prevent gonorrhoea, can help bring about the development of viable gonococcal vaccines.
Evaluating the factors responsible for post-fire water quality response in forests of the western USA
Authors: Rust Ashley J. , Saxe Samuel , McCray John , Rhoades Charles C. , Hogue Terri S.
Published: September 2019

Wildfires commonly increase nutrient, carbon, sediment and metal inputs to streams, yet the factors responsible for the type, magnitude and duration of water quality effects are poorly understood. Prior work by the current authors found increased nitrogen, phosphorus and cation exports were common the first 5 post-fire years from a synthesis of 159 wildfires across the western United States. In the current study, an analysis is undertaken to determine factors that best explain post-fire streamwater responses observed in those watersheds. Increased post-fire total nitrogen and phosphorus loading were proportional to the catchment extent of moderate and high burn severity. While post-fire dissolved metal concentrations were correlated with pre-fire soil organic matter. Total metal concentration increased where post-fire Normalised Difference Vegetation Index, a remote sensing indicator of live green vegetation, was low. When pre-fire soil field capacity exceeded 17%, there was a 750% median increase in total metals export to streams. Overall, the current analysis identified burn severity, post-fire vegetation cover and several soil properties as the key variables explaining extended post-fire water quality response across a broad range of conditions found in the western US.
Multipath interference from large trapped ion chains
Authors: Obšil P , Lešundák A , Pham T , Araneda G , Čížek M , Číp O , Filip R , Slodička L
Published: September 2019

The demonstration of optical multipath interference from a large number of quantum emitters is essential for the realization of many paradigmatic experiments in quantum optics. However, such interference remains still unexplored as it crucially depends on the sub-wavelength positioning accuracy and stability of all emitters. We present the observation of controlled interference of light scattered from strings of up to 53 trapped ions. The light scattered from ions localized in a harmonic trapping potential is collected along the ion crystal symmetry axis, which guarantees the spatial indistinguishability and allows for an efficient scaling of the contributing ion number. We achieve the preservation of the coherence of scattered light observable for all the measured string sizes and nearly-optimal enhancement of phase sensitivity. The presented results will enable realization and control of directional photon emission, direct detection of enhanced quadrature squeezing of atomic resonance fluorescence, or optical generation of genuine multi-partite entanglement of atoms.
Ab initio investigation of excited state dual hydrogen bonding interactions and proton transfer mechanism for novel oxazoline compound*
Authors: Wang Yu-Sheng , Jia Min , Zhang Qiao-Li , Song Xiao-Yan , Yang Da-Peng
Published: September 2019

Owing to the importance of excited state dynamical relaxation, the excited state intramolecular proton transfer (ESIPT) mechanism for a novel compound containing dual hydrogen bond (abbreviated as “1-enol”) is studied in this work. Using density functional theory (DFT) and time-dependent density functional theory (TDDFT) method, the experimental electronic spectra can be reproduced for 1-enol compound. We first verify the formation of dual intramolecular hydrogen bonds, and then confirm that the dual hydrogen bond should be strengthened in the first excited state. The photo-excitation process is analyzed by using frontier molecular orbital (HOMO and LUMO) for 1-enol compound. The obvious intramolecular charge transfer (ICT) provides the driving force to effectively facilitate the ESIPT process in the S1 state. Exploration of the constructed S0-state and S1-state potential energy surface (PES) reveals that only the excited state intramolecular single proton transfer occurs for 1-enol system, which makes up for the deficiencies in previous experiment.
Theoretical investigation of the pressure broadening D1 and D2 lines of cesium atoms colliding with ground-state helium atoms
Authors: Abdelaziz Moussaoui , Kamel Alioua , Abdul-rahman Allouche , Moncef Bouledroua
Published: September 2019

Full quantum mechanical calculations are performed to determine the broadening in the far wings of the cesium D1 and D2 line shapes arising from elastic collisions of Cs atom with inert helium atoms. The potential energy curves of the low-lying CsHe molecular states, as well as the related transition dipole moments, are carefully computed from ab initio methods based on state-averaged complete active space self-consistent field–multireference configuration interaction (SA-CASSCF–MRCI) calculations, involving the spin–orbit effect, and taking into account the Davidson and BSSE corrections. The absorption and emission reduced coefficients are determined in the temperature and wavelength ranges of 323–3000 K and 800–1000 nm, respectively. Both profiles of the absorption and the emission are dominated by the free–free transitions, and exhibit a satellite peak in the blue wing near the wavelength 825 nm, attributed to

B

2

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1

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2

+

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X

2

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+

transitions. The results are in good agreement with previous experimental and theoretical works.
Comparison of DSSP and tSSS algorithms for removing artifacts from vagus nerve stimulators in magnetoencephalography data
Authors: Cai Chang , Kang Huicong , Kirsch Heidi E , Mizuiri Danielle , Chen Jessie , Bhutada Abhishek , Sekihara Kensuke , Nagarajan Srikantan S
Published: September 2019

Objective. Large-amplitude artifacts from vagus nerve stimulator (VNS) implants for refractory epilepsy affect magnetoencephalography (MEG) recordings and are difficult to reject, resulting in unusable data from this important population of patients who are frequently evaluated for surgical treatment of epilepsy. Here we compare the performance of two artifact removal algorithms for MEG data: dual signal subspace projection (DSSP) and temporally extended signal space separation (tSSS). Approach. Each algorithm’s performance was first evaluated in simulations. We then tested the performance of each algorithm on resting-state MEG data from patients with VNS implants. We also examined how each algorithm improved source localization of somatosensory evoked fields in patients with VNS implants. Main results. DSSP and tSSS algorithms have a similar ability to reject interference in both simulated and real MEG data if the origin location for tSSS is appropriately set. If the origin set for tSSS is inappropriate, the signal after tSSS can be distorted due to a mismatch between the internal region and the actual source space. Both DSSP and tSSS are able to remove large-amplitude artifacts from outside the brain. DSSP might be a better choice than tSSS when the choice of origin location for tSSS is difficult. Significance. Both DSSP and tSSS algorithms can recover distorted MEG recordings from people with intractable epilepsy and VNS implants, improving epileptic spike identification and source localization of both functional activity and epileptiform activity.
Analysis of vibration characteristics of mounting plate for molded case circuit breaker
Authors: Pan Ying , Tang Zhixian , Cheng Zhi
Published: September 2019

This paper presents a framework to analyze the vibration characteristics of mounting plates for molded case circuit breakers (MCCB). Two different three-dimensional models for mounting plate I and II are established in ANSYS Workbench simulation platform through reasonable simplifications. The preceding six-order natural frequencies are obtained by means of modal analysis. Based on the experimental data of modal analysis, random vibration analysis of mounting panel I and II is conducted. It is concluded that mounting plate I is easy to deform permanently when its 3δ stress exceeds the yield limit of material, while mounting plate II meets the strength requirements and is better suited to test requirements.
A MATLAB post-process method of vehicle cold start data
Authors: Qian Feng , Li Peng , Zhu Neng , Xu Xiaowei
Published: September 2019

Gasoline vehicle cold start calibration is one of the important calibration work content. And the important evaluation criterion of cold start is start time, overshoot, undershoot. At present, the calibration engineers in most companies mainly use ETAS/INCA software to record test data, and then use MDA software to analyse start time, overshoot and undershoot. But the cold start test data is so huge, so the post-processing efficiency is very low. Facing this problem, the post-processing tool of cold start data based on MATLAB is established. With this tool, the huge amount of data can be processed efficiently, and key start mode or start-stop mode can be distinguished clearly. So it can greatly improve the post-processing efficiency of cold start data.
Monitoring the spontaneous combustion of coal stack based on ZigBee and LabView
Authors: Zheng Yu , Lv Fang , Li Deqin , Gao Bingqian
Published: September 2019

The spontaneous combustion of coal piles is a great threat to all coal storage sites. In order to avoid the occurrence of spontaneous combustion of coal piles and reduce economic losses and casualties, a set of system is designed to monitor the internal temperature of coal piles and predict the temperature value and combustible gas concentration. The system has the advantages of monitoring and warning, short-term prediction and low power consumption.
Optimization the first frequency modal shape of a tensural displacement amplifier employing flexure hinge by using Taguchi Method
Authors: Vu Ngoc Chien , Huynh Ngoc Thai , Huang Shyh Chour
Published: September 2019

The high amplification ratio, high frequency, and larger workspace always ask in compliant mechanisms. Thus, in this investigation optimized design dimension to select an optimal model for a tensural displacement amplifier employing flexure hinge by utilizing Taguchi method based on finite element analysis (FEA). The Solidworks software was applied to design the model, the first modal shape frequency was gained by FEA in ANSYS. The orthogonal L27 was applied to design 27 experiments. The data was collected from 27 cases which were analyzed by signal to noise, ANOVA and regression analysis (RA). The simulation results indicated that thickness of flexure hinge (TOFH) made significant increasing the 1st natural frequency when its rises from 0.3 mm to 0.7 mm and decreased as incline angle between two flexure hinges rises from 00 to 0.50. The phenomena also confirmed by S/N analysis, ANOVA and RA. The optimal value of the frequency obtained 214.06 Hz is good agreement with the forecasted value of 198.1758 Hz with deviation error of 7.15%.
Development of foreign matter removal robot for overhead transmission lines
Authors: Zhang Yaodong , Li Jinbin , Li Cheng , Tao Qian , Xiong Xiaomin
Published: September 2019

In recent years, the limitations of artificial live working have become increasingly prominent. Researching robot technology that replaces manual work has become an important branch of intelligent research on power maintenance. In this paper, the objects and tasks of foreign matter removal in overhead transmission lines are analyzed. The structure of the robot is introduced, and the control method and software design of the robot system are described. The test and field application show that the robot is reliable, stable and easy to control. It can remove floating foreign matters on the overhead line, meet the requirements of live working of the transmission line, and can replace the manual removal of foreign objects.
Research in Torque Distribution of Dual Motor Electric Vehicle Based on PSO
Authors: Xie Jinfa , Liu Han , Li Bochao , Xie Ning
Published: September 2019

This paper proposed real-time optimization algorithm in order to solve the problem which the dynamic nonlinear torque distribution of rear dual-hub-motor-driven vehicle. Based on the research of a company’s rear-wheel drive double-wheel hub motor, build the control model by MATLAB, the vehicle model set up by CarSim, and Co-simulation test the performance of algorithm. Then hardware-in-loop test based on the VCU. The result shown that the algorithm could distributed torque according to the actual working conditions, reduced the slip ratio, improved the driving performance of vehicle.
Numerical simulation of surface diffusion motion and its application in MEMS fabrication
Authors: Zhang Yujie , Zeng Fan , Wong Man , Xiang Junping , Ye Wenjing
Published: September 2019

Surface diffusion motion has been proposed as a new technique, called Silicon Migration Technology (SiMiT) for the fabrication of Micro-Electro-Mechanical System (MEMS) devices. Using this new technology, the integration of MEMS-CMOS can be achieved without the “sacrificial-structural” layers and “release-etch” procedure, which are necessary in traditional approaches. However, numerical simulation of surface diffusion process is still a challenging task due to the stiffness nature and the topological changes during the process. In this paper, we adopted a high-order explicit level-set method based on the total variation diminishing Runge-Kutta (TVD-RK) method, a high-order scheme for distance computation. An efficient smoothing scheme is proposed to increase the numerical stability and an adaptive time marching scheme is developed to accelerate the simulation. Experimental investigation of shape transformation of silicon trenches is carried out to verify the accuracy of the numerical scheme. Results show that numerical simulation results match quite well with experimental ones, which suggests the accuracy and reliability of the numerical simulation in the application of MEMS design.
Analysis of cracking causes of micro-spray desuperheater for 1025T/H boiler reheater
Authors: Pang Linya , Yang Qingxu , Feng Lizhong , Yang Xianbiao , Liu Xubi
Published: September 2019

A power plant 1025t/h boiler reheater micro-spray desuperheater fixed desuperheating water nozzle tube fillet weld cracking, after inspection and test, analyzed the cause of cracks. The analysis concluded that the welding quality of the end cap of the sprinkler is poor, and the plug weld has a leak point. During the desuperheater operation, the leaked desuperheating water is directly sprayed on the desuperheater cylinder, the fixed stem and the nearby mother. A large number of thermal fatigue cracks are generated under the action of alternating thermal stress, and gradually expand into penetrating cracks under the environment of long-term high temperature and high pressure. In order to avoid the recurrence of similar cracking leakage, it is recommended to replace the failed desuperheater and check the same parts of other desuperheaters and at the same time strengthen the supervision of the desuperheater installation quality.
Analysis of vibration characteristics of cylindrical linear induction motor
Authors: Liu Wei , Xu Jin , Huang Chuibing
Published: September 2019

Due to the non-periodic operation of the cylindrical linear induction motor, the vibration characteristics cannot be studied by the conventional steady-state method. In this paper, the finite element modal analysis method is used to describe the natural vibration characteristics of linear motor with different connection conditions, and the contribution factors of modal on the overall vibration are quantitatively analyzed. Besides, the modal change law of linear motor is analyzed, and the transient dynamics method is used to investigate the transient forced vibration characteristics of the linear motor during the movement of the mover. The research shows that the elastic connection can greatly reduce the natural vibration frequency of the linear motor; when the excitation force is applied, the mover bracket is the most easy to vibrate; the motion of the mover has little effect on the linear motor mode, and the difference is reflected in the different mode of stator because of the different relative position of mover and stator.
Solutions optimization of decreasing rail friction for bolts mechanical power consumption
Authors: Xu Jian , Yang Zhen , Li Qiang
Published: September 2019

In other to save energy, several countries recently made laws related to mechanical power consumption. Motion Acceleration is known to affect the mechanism power. In order to reduce the minimal driving power, the gun bolts velocity and the main roller relative to whole body and the right-and-left rail and obliquity of rail are researched. The result indicates that the best situation is minimum acceleration of bolt group cam and the main roller relative to whole body is zero, and it is good in non-altitude difference with bilateral angle. The optimization results show that in the case of high rate it is very good to low rate, and the force prompt drops as the high fire ratio to low ratio.
Study on simulation model and performance test of locomotive anti-skid valve
Authors: Lu Yi , Zhou Jinhao , Guo Bin
Published: September 2019

When studying the comprehensive performance of the anti-skid valve, the test of the curve characteristic lacks theoretical basis in the brake anti-skid process and the mathematical equations are difficult to derive. Take a domestic locomotive anti-skid valve as the research object. Combine with the physical structure parameters of the anti-skid valve and the working principle of inflating and exhausting. A simulation model of the anti-skid valve was established by using MATLAB/Simulink, which included the motion equation of valve core and diaphragm plate, electromagnetic suction equation of electromagnet and air chamber charging and exhausting equation. The characteristics of the air pressure curve of the anti-skid valve under different control signals were analyzed. In order to verify the correctness of the simulation model, a set of locomotive anti-skid valve comprehensive performance test bench based on STM32 was built for experimental verification. The results show that the simulation results are consistent with the experimental results, meet the test requirements, and verify the accuracy of the model. This model provides a theoretical basis for structural optimization of anti-skid valves and analysis of locomotive braking anti-skid performance.
A study on large parts precision docking method based on 6-axis industrial robot
Authors: Guo Rui , Du Jinsong , Zheng Dechao , Lu Bolin , Yin Jian
Published: September 2019

In view of the docking assembly difficulties of spacecraft large parts, resulting from the irregular contour and the inadequacy of process clamping points, this paper puts forward a method fitting the attitude relations of the docking parts based on the coordinates of the feature points, obtaining the target attitude of the docking parts based on the process constraints, and controlling 6-axis industrial robot achieves precise docking of large parts. Firstly, the composition of the large parts docking system is introduced, and the docking model is described by the selection of the measurement feature points and the establishment of the coordinate system. After that, a docking control algorithm based on the attitude constraints of large parts is established. Finally, In the RobotStudio and Matlab co-simulation environment, the attitude adjustment process of the large parts is simulated. The simulation results show that this study provides an effective method for precision docking of spacecraft engine large parts based on feature points, which is completed by 6-axis industrial robot.
Kinematic analysis and visual grasping algorithm of collaborative robot
Authors: Liu Li , Zhang Dongmei , Gao Yi
Published: September 2019

This paper mainly studies the kinematics analysis and visual capture algorithm of collaborative robots. First, the mechanical structure of the cooperative robot was analyzed. Then, the kinematics equation of the cooperative robot was solved by numerical iterative method. The correctness and rapidity of the algorithm were verified by simulation. Finally, a visual compensation method based on image edge contour features is proposed. The multi-target area processing was used to realize the positioning of the workpiece’s three-dimensional spatial information, and the collaborative robot was guided to capture the operation to ensure the positioning accuracy.
Research on seismic performance of composite concrete slab with no-protruding rebar shear wall joints
Authors: Xie Yonglan , Wang Dongyan , Qi Hu , Liu Kang
Published: September 2019

Precast concrete composite slab is one of the most widely used precast elements in civil engineering, which is suitable for all kinds of prefabricated concrete structure. The longitudinal bars at the bottom of precast slab extend beyond the ends of it, which brings a lot of inconveniences in fabrication, transportation and installation. In order to avoid those disadvantages of traditional precast concrete composite slab, a new no-protruding rebar concrete slab shear wall joint is developed in this paper. And five concrete slab-shear wall joint specimens were fabricated to research the joint structure of composite slab with no-protruding rebar but including additional rebar. In order to verify the seismic performance of the new concrete slab-shear wall joint, Pseudo-static testing of those specimens were carried out and the bearing capacity, stiffness, ductility and energy-dissipating capacity of different specimens were compared. The experiment results show that the additional rebar is necessary to the joints of composite slab with no-protruding rebar shear wall to ensure the seismic reliability of the joint connection; the bearing capacity and ultimate deformation of the new no-protruding rebar concrete slab-shear wall joint increase with the increasing of the lapped length of additional rebar.
Optimization design of structure parameters of dynamic recoil device
Authors: Li Peng , Chen Yongcai , Yang Yuliang
Published: September 2019

The muzzle dynamic recoil device for guns was designed. The optimization of dynamic recoil device was studied in detail. Using the MATLAB optimization toolbox, a series of optimized parameters of dynamic recoil device were got. By compared the results of dynamic recoil test with live-fire of the gun, the rationality and practicability of the dynamic recoil device has been proved. It is also proved that the muzzle dynamic recoil device can meet the dynamic recoil test requirements of guns.
Automobile newborn - new energy vehicle
Authors: Xu Fengfeng , Zhang Shaoguo
Published: September 2019

With the environmental pollution, energy shortage, the environment on the traditional fuel car carrying capacity is becoming smaller and smaller, and the new energy car in life is becoming more and more important. This paper mainly describes the classification of new energy vehicles as well as their advantages and disadvantages, and puts forward the corresponding improvement methods.
Application of a multi-input multi-output (MIMO) nonlinear non-minimum phase system control method to hydro turbine unit
Authors: Wang Wancheng , Qiu Song , Xu Jiao
Published: September 2019

In this paper, in view of the non minimum phase characteristics of hydraulic turbine unit, a method of designing the controller of multi-input multi-output (MIMO) nonlinear non-minimum phase system is proposed and applied to hydraulic turbine unit system described by double control input fifth order model. The turbine output electromagnetic power and generator power angle are stabilized by wicket gate opening and excitation combined control. Firstly, the method for designing the controller of multi-input multi-output (MIMO) nonlinear non-minimum phase system is introduced. The method is based on state feedback theory, pole assignment theory and Lyapunov stability theory. Secondly, the control law of hydro turbine unit is given according to the method. Results of simulation indicate that this nonlinear non-minimum phase controller has a good effect when applied to the hydro turbine unit.
Dynamic modeling and simulation of 4X4 wheeled vehicle
Authors: Chen Yijie , Zhang Yafeng , Du Fu , Wang Le , Wan Yiqiang
Published: September 2019

In view of the requirements of military vehicles for high-mobility off-road performance, the dynamic modeling of 4X4 wheeled armored vehicles was carried out. The dynamic model expression expressed in matrix form was derived, and the decoupling calculation was performed by Fourier transform. After that, the power spectral density function was used to characterize the random road input of the vehicle, and the coherence of each wheel excitation in the four-wheeled vehicle was analyzed to derive the coherence coefficient. Finally, the calculation method of vibration response of vehicles under typical roads was formed by programming analysis and reasonable algorithm, and it provided theoretical support for suspension vibration isolation performance design.
Optimization effects of design parameter on the first frequency modal of a Bridge-type compliant mechanism flexure hinge by using the Taguchi method
Authors: Wang Chia Nan , Truong Kim Phung , Huynh Ngoc Thai , Nhat Hoang Le Quang
Published: September 2019

The compliant mechanism always requests high displacement amplification ratio and high vibration frequency. Therefore, this paper optimized design parameters to obtain the maximum value of the first frequency modal shape using the Taguchi method. First, the model was designed by Solidworks. Second, effect design parameters on the first frequency modal shape were analyzed via ANSYS Workbench 18.0, and the final the maximum value of the first frequency modal was obtained by the Taguchi method. The simulation results revealed that the thickness and width of flexure hinge has a significant effect on the first frequency modal. The S/N analysis results demonstrated that the thickness of the flexure hinge has a significant affect next to the width of the flexure hinge, inline angle between two flexure hinges, input body length, and the fillet radius of the flexure hinge. The ANOVA analysis results identified that the contribution percentage of design parameters and fillet radius of the flexure hinge have a significant effect on the first frequency modal. The R-square was obtained at 99.84%, and the maximum value of the first frequency modal was obtained at 821.8267 Hz.
A research on blind area of random layout units for localization
Authors: Wang Zhizhuan , Li Ling , Li Guijuan , Wang Yang
Published: September 2019

Acquisition distance information of the underwater target is very important to evaluate the target noise level, so it is necessary to do some research on the passive localization method for the underwater target. In this paper, the multi-hydrophone units model is used to passively achieve target localization information in the underwater environment; the accurate DOA estimation and ranging calculation method are presented. The localization blind area problem with different units models is discussed. The blind area problem caused by traditional passive localization model (three units) is solved by the method with four random units, which can locate the underwater unpredictable target in arbitrary direction.
Rapid development of SAR backward projection imaging algorithm based on MATLAB
Authors: Zhang Jiaqi , Li Lianghai , Zhang Zhenhua
Published: September 2019

This paper introduces a kind of FPGA rapid development method to complete the backward projection algorithm of SAR. Firstly, the traditional FPGA development has strict requirements for developers’ software and hardware knowledge. Then we introduce a kind of FPGA rapid development method based on the 2018(a) version of MATLAB’s Simulink of MATLAB. And then, the algorithm is divided into two parts, one is the range pulse compression part, and the other is the backward projection part. In order to make full use of the parallelism of BP algorithm, this paper divides the dates into four parts in the distance direction and the imaging grid is also divided into four parts. The projection grid is still based on the whole grid, which can improve the real-time performance of the algorithm. After the algorithm is modeled in Simulink, the model can be converted to the corresponding FPGA code by using the fixed point tool. The comparison of Scope display results with MATLAB results demonstrates the effectiveness of this MATLAB-based Simulink tool for FPGA development.
Design of marine environmental noise signal generation system based on MATLAB, LabVIEW and FPGA
Authors: Gao Feng , Meng Chunxia
Published: September 2019

Marine environmental noise is a background interference field produced by various underwater sound sources. The characteristics of marine environment vary with time, place and frequency. In order to simulate the marine environmental noise signals with different time-frequency characteristics, a real-time generating system of marine environmental noise signals is designed based on MATLAB, LabVIEW and FPGA. According to the probability distribution of the measured frequency characteristics of marine environmental noise, the random signals with specific frequency response are calculated and generated in real time and continuously. The pool test results show that the signal generation system has the characteristics of stable real-time calculation and signal generation. Based on the marine environmental noise signal generation system designed in this paper, time-domain waveforms with specific spectrum characteristics are generated, which will provide technical support for the research of random signal processing algorithm under laboratory conditions and the performance analysis of underwater acoustic equipment under different marine background conditions.
Research on battery-supercapacitor hybrid energy storage control scheme for mine electric locomotive
Authors: Zhu Longji , Hu Kunmin
Published: September 2019

The starting and acceleration of the mine electric locomotive requires instantaneous high-power output of the power supply. The power density of lead-acid battery is low, which cannot meet the high-power demand of the mine electric locomotive. In order to make up for the shortage of the battery as a single power supply for the mine electric locomotive, A battery-supercapacitor hybrid storage system (HES) with lead-acid battery as main power supply and supercapacitor as auxiliary power supply is proposed. A multi-input DC/DC converter is adopted to control the output of the HES under different working conditions of the electric locomotive, and the bidirectional power control of the HES is realized. The simulation results show that the HES scheme plays a good role in driving and energy feedback of the mine electric locomotive.
Research on pose point cloud matching error compensation method for confocal image assembly
Authors: Zhao Yijin , Ye Xin , Wang Lei , Yu Xinhai , Zhang Heng
Published: September 2019

High-precision matching of spatial poses is the key to ensuring the assembly performance of complex three-dimensional devices. The human eye cannot directly judge the three-dimensional pose of mesoscale devices, and high-precision observation instruments are needed to assist accurate judgment, ensuring smooth assembly. In this paper, based on the three-dimensional assembly system of micro-devices of confocal microscope, it is difficult to realize the problem of assembly alignment of spatial poses in the existing methods, this focuses on solving the problem of how to perform high-precision pose matching by using point cloud data measured through the confocal microscope.A new method for directly performing alignment of three-dimensional poses is proposed. The principle of point cloud registration ICP algorithm is studied, and the theory of point cloud axis hole registration theory is carried out.A neural network about the mapping relationship between the angle calculated by the RT matrix obtained by ICP algorithm and the theoretical angle is constructed. The comprehensive assembly accuracy of the whole method is analyzed to be 2.41μm. Finally, the actual experiment was carried out through the standard hole axis of 3μm for the single-edge gap and assembled successfully.
MPPT control of solar energy collecting circuit based on state estimation of solar cells
Authors: Zheng Mingcai , Zheng Jinbing , Zhao Jinqin , Zhao Xiaochao
Published: September 2019

In order to maximize the power output efficiency of Solar cells and the solar energy collection efficiency of collecting circuit, it is needed to track the real-time status of Solar cells, and force solar cells to work at its MPPT working point by an appropriate control method. Aiming at the solar energy collecting circuit based on Boost structure DC/DC converter, a MPPT control method based on the state estimation of Solar cells (MPPT-SE) is presented. In the MPPT-SE control method, the MPPT current value of solar cells is estimated by detecting solar cells’ output status and estimating its internal equivalent state, and the actual output current of solar cells is controlled to track its MPPT current value by current closed-loop control, this can force solar cells to work near its MPPT working point and maximize the power output efficiency of Solar cells and the solar energy collection efficiency of collecting circuit. The theoretical analysis and experiment results validate that the solar energy collecting circuit based on MPPT-SE method has higher power output efficiency and solar energy collection efficiency.
Online detection method for holes co-axiality of aero-engine
Authors: Fu Qingyan , Hu Tingzhi , Xiao Muzheng , Jin Xin , Pu Yimin , Wang Shiming , Zhang Zhongqing , Zhang Zhijing
Published: September 2019

In recent years, the requirement for the assembly performance of aero-engine is getting higher in the aviation field. As the key indicator which can affect engine performance, the demand of detection accuracy of rotor bearing holes’ coaxial error is increasing. In the engine’s assembly process, the traditional manual mechanical detection cannot measure the assembled holes’ co-axiality directly, and must be carried out by the fixed tools after the trial assembly. This results in the long assembly time, low productivity, and low detection accuracy. An online detection method which can better ensure the products’ assembly quality must be proposed. Based on the analysis of the related research status of co-axiality detection at home and abroad, combined with the laser alignment technology and the axle hole centering measurement technology, an online measurement method based on the laser alignment is proposed, and a co-axiality detection system of the turbofan engine for specific models is introduced, whose centering error is less than 4μm. Besides, a universal co-axiality detection method of the engine rotor shaft hole is obtained, which could optimize the assembly process and improve the assembly efficiency.
The Vehicle collision warning system detects the vehicle ahead
Authors: Deng Ling , Zhou Yan
Published: September 2019

In the field of computer vision and deep learning, vehicle identification is an important subject, which can be applied to the traffic auxiliary system, which can greatly reduce the occurrence of traffic accidents. In this paper, a large number of positive and negative samples are collected, and the algorithm of AdaBoost cascade classifier is used to train the classifier based on Haar feature and LBP feature. Finally, the selected feature and classifier are used for testing. Experimental results show that both of the two eigenvalues have better characteristics and higher detection accuracy when detecting the target vehicle, but LBP features have a faster detection speed, while Haar features have a higher accuracy.
Design of inter-stations H∞ decoupling controller in VSC-HVDC system
Authors: Yu Yu , Li Hongliang , Chen Qijiang , Tian Ye , Xu Lichao
Published: September 2019

The purpose of this work is to reduce the mutual interference between converter stations when the AC power or DC voltage fluctuates in VSC-HVDC system. The global small signal mathematical model of VSC-HVDC system is established firstly. Then, according to the principle of mixed sensitivity H∞ robust control, the appropriate weight function is selected and the decoupling controller between stations is deduced. In addition, the high-order controller deduced is reduced to an appropriate order which is beneficial to engineering application by using the balanced truncation method of coprime factors. Finally, the electromagnetic transient simulation is carried out to verify that the H∞ decoupling controller between stations can be effectively weakened the interaction between two converter stations and improves the dynamic performance and robust stability of the system.
Fault diagnosis of power grids based on grey relational analysis
Authors: Lu Huayong , Guo Hongzuo , Liu Zhe , Yang Xiao , Leng Bing
Published: September 2019

A fault diagnosis method of power grids was presented based on grey relational analysis in this paper. For each suspected fault line in the power cut area, the grey relational of original characteristics sequence, amplitude and energy are calculated by using the current sampling value before and after the fault time. Then an active reference line was selected, followed by the calculation of the horizontal grey correlation between reference line and suspected fault line according to current sampling after the fault. Finally, the longitudinal grey relational degree and the horizontal grey relational degree of each line are weighted and fused to obtain their comprehensive grey relational degree, and the fault criterion is given to identify the faulty component accurately. The simulation results of the IEEE 14-node system show that the fault elements can be identified under different fault locations, various fault types and different transition resistances accurately.
Research on fault analysis of pumping station units based on stack auto-encoder
Authors: Zhao Linzhang , Gao Chenghao
Published: September 2019

The stack Auto-encoder is applied to the fault analysis of pumping station units, and a fault analysis model based on stack automatic encoder is constructed. The model consists of an input layer, 3 hidden layers and an output layer to realize feature extraction and dimension reduction of the monitoring data of the pumping station unit. The network uses unsupervised layer-by-layer greedy methods to train, then uses backpropagation algorithms to optimize network parameters and uses the softmax classifier for classification. The experiment proves that the average classification accuracy rate of unit failure and different working conditions reaches 79.8890%, which can provide a certain reference for unit failure analysis.
Controller design for a nozzle-flapper type servo valve with electric position sensor
Authors: Istanto Iwan , Lee Ill-Yeong , Huh Jun-Young , Lee Hyun-Cheol
Published: September 2019

The control performance of hydraulic systems is basically influenced by the performance of the electro-hydraulic servo valve incorporated in a hydraulic control system. In this study, the authors propose a control design to improve the control performance of a servo valve with a non-contact eddy current type position sensor. A mathematical model for the valve is obtained through an experimental identification process. A PI-D control together with a feedforward (FF) control is applied to the valve. To further improve the dynamic response of the servo valve, an input shaping filter (ISF) is incorporated into the valve control system. Finally, the effectiveness of the proposed control system is verified experimentally.
Multi-Objective collaborative planning for distribution networks considering electric vehicle charging stations and distributed generation
Authors: Zheng Yunfei , Sang Zixia , Wang Yingxiang , Li Xiang , Wang Rian , Kong Shunfei , Hu Zhijian
Published: September 2019

The large investment of electric vehicles and distributed generation has affected the stable operation of distribution network. At the same time, the construction of charging station of electric vehicles not only causes the burden of electric power network, but also the burden of transportation network. How to ensure the stability and economics of distribution network has become an urgent problem. Based on this background, this paper proposes a multi-objective collaborative planning method for distribution network, which considers the charging station of electric vehicle and the distributed generation. In order to find the optimal planning scheme, we use an improved NSGA-II algorithm. Finally, the simulation analysis of the case of IEEE 33-bus shows that the proposed planning method not only ensures the stability and economics of distribution network, but also fully saves the average waiting time of charging users of electric vehicles and improves the traffic satisfaction.
Design of rolling ball control system based on OpenMV
Authors: Zhou Linjie , Xu Enyi , Chen Donghong , Xu Chenghao , Chen Xiai , Xu Suan , Wang Ling
Published: September 2019

The ball-on-plate system, a non-linear control system with a 2-degree of freedom, is crucial for understanding the control system applications. As increase of the non-linearity with the degree of freedoms, the system can be used to test and identify different aspects of controls. This paper describes the design and implementation of a ball-on-plate system based on OpenMV that includes machine vision modules. Camera OV7725 with chip model of STM32F765 in OpenMV detects and calculates ball position on the plate in real time, and then the OpenMV sends the position data of the ball to the main Micro Controller Unit through a serial port. The MCU calculates the data with a cascade PID controller, and outputs the PWM wave to control the rotation angle of the steering engine. The steering engine drives two vertical parallelogram linkage mechanisms to manipulate the motion of the plate. Thus, the system can exactly control the motion state and position of the ball on the plate in real time.
The design and implementation of vehicle-mounted satellite communication on the move based on MEMS gyro
Authors: Xi Xiaopeng , Su Min
Published: September 2019

As an important satellite communication technology, mobile communication has broad application prospects in the field of military and civilian applications. Low cost and high reliability have become one of the goals and difficulties in engineering design. In order to overcome the shortage of course information provided by inertial navigation or electronic compass, a beacon space search algorithm without course information is designed. A low cost gyro stabilization platform based on ARM and MEMS gyroscope is designed for the high mobility and complex working conditions of vehicles. The servo motor and photoelectric encoder are used to construct the multi-closed-loop control system to improve its fast response ability, and the pitch compensation and beacon space search algorithm are used to improve the precision of the system for star and tracking. It has good engineering application and popularization value.
Variable step size tracking algorithm for the VICTS antenna
Authors: Zhang Zhiyong , Lei Xue , Xu Zhijian , Li Tianpeng , Gao Jun
Published: September 2019

A variable step size tracking algorithm for the Variably Inclined Continuous Transverse Stub (VICTS) Antenna for Ku-band fixed-satellite service is proposed. The traditional step tracking algorithm is improved by using and the simulation analysis of the VICTS antenna to get the apposite step size. And the feasibility and superiority of the algorithm are verified by the failure rate of locking the satellite. The proposed algorithm provides a feasible method for the VICTS antenna servo system to achieve satellite communication on the move (SOTM).