bluuebunny/crossref_metadata_2025 huggingface dataset:
An LDO Circuit Design Based On On-chip Compensation
Authors: Yang Hualei , Wu Chenjian
Published: December 2022

This paper proposes a liner low-dropout regulator (LDO) circuit using on-chip steady-state compensation technology. Firstly, a bandgap reference is designed with low temperature drift and low power consumption. Secondly, the on-chip compensation is adopted in the LDO, which can avoid the use of large off-chip capacitors and reduce the layout area of the LDO circuit. The circuit performances are verified in the TSMC 180 nm CMOS process. Test results show that temperature coefficient of the bandgap reference circuit is as low as 4.3 × 10-6 °C in the temperature range of -40°C to 125°C. The static current under the 3V power supply voltage is 4 μA. The LDO output voltage Vout
is 1.8V . And the core area of the chip is 0.0848 mm2.
Optimization Design of Feed Tower for High-frequency Band Multi-beam Antenna on Satellite
Authors: Xue Zhaoxuan , Zhang Xingang , Hou Jian , Liu Xi
Published: December 2022

Aiming at the layout of a certain feed array for multi-beam antenna on satellite, a feed tower design method based on 3D printing technology is proposed. This design method uses aluminum alloy 3D printing to form the main support structure under the premise of avoiding the installation holes and layout positions, and adopts the combination of the main structure of the honeycomb lattice and the local solid structure to reduce the structural quality. The mechanical analysis and optimization of the design model are carried out by combining the actual test data of the mechanical test plate and ANSYS, in which the actual product is tested and verified. The light feed tower can fully meet the requirements of high-frequency multi-beam antenna feed array for high precision and lightweight, which has a certain reference value for the miniaturized design of the antenna.
Open-circuit Fault-tolerant Control for Three-phase Permanent Magnet Synchronous Motor
Authors: Lu Zhiqi , Fang Ziwen , Huang Jun , He Xiaobin , Yang Aiwei
Published: December 2022

In this paper, a single-phase open-circuit fault-tolerant control method for three-phase permanent magnet synchronous motor (PMSM) is proposed. Based on the 4-leg inverter and the redesigned vector transformation method, the switching of the motor control strategy after a single-phase open circuit can be realized, and the control characteristics of the motor are unchanged. This fault-tolerant control method can be easily combined with other control strategies and has a wide range of applications.
Modeling Analysis of Superbuck Converter in Dual-Loop Competition Control
Authors: Fu Beinan , Xu Mochen , Dou Yinghua , Dong Baolei , Liu Tao
Published: December 2022

A Battery Charge Regulator system based on the Superbuck converter is presented, the working principle of the Superbuck converter is analyzed and the small signal model is established. In order to meet the requirements of wide input range and high dynamic response of the Superbuck converter, a double closed-loop control system is designed with output voltage and output current dual loop control as outer loop and input current control as inner loop. The stability of the control loop is verified by the Bode plot, and the simulation result of the system in two working conditions are given to support the theoretical analysis.
Life Prediction Method of Electromagnetic Contactor Based on Fusion of Improved Particle Filter and Degradation Model
Authors: Zan Jianhua , Chen Chunjun
Published: December 2022

Electromagnetic contactors are the key components of high-speed trains. A reasonable evaluation of the remaining life of the contactors can optimize the replacement cycle of the contactors and ensure the safe operation of the train. Aiming at the problem of remaining life prediction of contactors, a contactor life prediction method based on the fusion of improved particle filter algorithm and performance degradation model is proposed. Firstly, on the basis of analyzing the failure mechanism of the contactor and establishing its electromagnetic and dynamic simulation model, a performance degradation model based on overtravel time is established. Then design the contactor life test to obtain its full life cycle degradation data. Next, the adaptive genetic algorithm is used to optimize the resampling process of the particle filter algorithm. Finally, the optimal parameter values of the performance degradation model are obtained by the improved particle filter algorithm, and then the prediction of the remaining life of the contactor is realized. The prediction results show that the method can effectively predict the remaining life of the contactor, and the prediction accuracy meets the actual engineering needs, which provides an important reference for the operation and maintenance of the electromagnetic contactor for high-speed trains.
ADS1299-Based Array Surface Electromyography Signal Acquisition System
Authors: Li Yuchang , Pan Hongqing , Song Quanjun
Published: December 2022

A multi-channel sEMG signal acquisition system based on the analog front-end chip ADS1299 is designed. The whole acquisition system consists of a 2×9 high-density electrode array, ADS1299 multi-channel high-precision A/D conversion chip; A MCU named STM32F103C8, an upper computer, and PC. We carried out electrode array design, The introduction of the function of the ADS1299 chip, and the circuit design of the analog signal acquisition part. The test results show that the acquisition system designed in this paper can ideally collect the sEMG signal of 8 channels on the back of the hand, which proves the effectiveness of this design in extracting weak EMG signals. Therefore, it has reference significance for designing larger-scale sEMG signal acquisition circuits.
A Method for Leakage Current and Power Reduction of Buffer in 65-nm CMOS Technology Based on the Pileup-Effect
Authors: Xu Hanyuan
Published: December 2022

In small-size Complementary Metal Oxide Semiconductor (CMOS) technology, the size of Very Large-Scale Integration (VLSI) below 90nm becomes higher and higher due to the enhancement of the short channel effect of transistors. CMOS Buffer is a very common circuit unit in VLSI. In this paper, a Pileup effect transistor (PET) is proposed to reduce the subthreshold leakage current of the CMOS buffer. The main principle of PET technology is to reduce the voltage difference between gate and source and the voltage difference between drain and source by lowering the voltage of source so as to reduce the subthreshold leakage current. Through simulation-based on Cadence and Taiwan Semiconductor Manufacturing Company (TSMC) N65 library, PET technology can reduce leakage current power consumption by about one-twelfth of the original while maintaining the function of the original CMOS buffer. PET technology has also been found to reduce current consumption in the transition state by about 40%.
Research on capacitive compensation based on underground pipeline detection system
Authors: Geng Shuqin , Zhu Ronghao , Li Pengkun , Lu Hang
Published: December 2022

This paper investigates the problem of wireless power transmission in underground pipeline detection systems. In response to the fact that during the study of the underground pipeline detection system, the coil inductance value changes due to environmental and anthropogenic factors, making the system detuned and unable to effectively acquire the underground microtag ID signal. Therefore, we raised a novel capacity compensation method to solve the problem mentioned above. Firstly, the hardware structure of the system is modelled, derived and analysed with the system in a resonant state. The topology applied to the system is then subjected to capacitive compensation operations to obtain the power transfer efficiency of the system in the resonant state with the best topology model. Finally, it is demonstrated through functional tests that the capacitive compensation of the optimal topology model achieves a good power transfer performance and acquires an effective ID signal.
Design of 1T2M integration of storage and calculation based on threshold memristor
Authors: Gao Sen , Li Lei , Huang Haoxuan , Li Shou , Pan Nan , Zhang BoLin , Jin Long
Published: December 2022

Memristor is a new type of electronic component with small size and non-volatile, and it is the most promising new electronic component to replace MOS tube. The computing and storage parts of the computing electronic machines we use today are separate. With the development of technology and new materials, the indicators of CPU and memory have undergone qualitative changes, but the data transmission of CPU and memory still needs to rely on the bus, which greatly reduces the performance of computing and storage. This paper studies the integration of storage and computing. The ultimate purpose of this experiment is to integrate computing and storage into one chip. This paper proposes a 1T2M memory-computing integrated circuit design based on threshold-type memristors. This circuit is a new circuit structure. This circuit consists of an NMOS transistor and two threshold-type memristors. This structure can realize “OR logic operation” and “storage”. The circuit structure is simple, the performance is better, the number of transistors is less, the integration level is higher, and the reading and writing speed is faster. The simulation verification is carried out by LTSpice.
A new multi-disk shaft balancing method for rotating machinery using strain gauges
Authors: Zhang Xiaobin , Zhang Ze , Xu Jidong , Si Paiyou , Liu Shuangbai
Published: December 2022

Unbalance is a major factor influencing rotating machinery vibration. In general, vibration problems caused by mass imbalance can be solved by dynamic balancing method. When dynamically balancing a flexible rotor, if the counterweight plane does not coincide with the unbalanced plane, it will cause the rotor to bend and deform, and the bending deformation will produce a new unbalance force. So, it is important to identify the unbalanced force on each plane. A method to solve this problem using strain gauges was presented. The equation to identify unbalance force at three or more planes of a shaft is set up. A series of tests were done on a rotor bearing rig. The tests show that unbalance weights and angles at different rotating speeds were identified with high accuracy. It is a new and effective method for multi-disk shaft balance.
Error analysis and compensation method of underground turbine motor voltage sensor
Authors: Xiao Wang
Published: December 2022

the control system of petroleum drilling engineering has been in a bad and high temperature environment for a long time. In the unknown downhole working environment, the signal detection accuracy of turbine motor determines the drilling quality and cost of rotary steering drilling engineering. In order to design a high-temperature voltage sensor that meets the needs of oil drilling engineering, this paper takes 206B voltage sensor as the experimental object, simulates the downhole environment, carries out high-temperature experiments on this type of sensor, and analyzes the influencing factors of its error. The experimental data show that the downhole turbine motor voltage sensor is most affected by temperature, and the 206B sensor can withstand a maximum temperature of 125 °C. In view of its temperature influence, the least square method is used to compensate the error. The compensated voltage sensor error is reduced to 1~3.048%, which effectively improves the accuracy of the turbine motor voltage detection device and can accurately receive the downward signal of rotary steering drilling, so as to greatly reduce the drilling cost.
A Fault Diagnosis Method of 25Hz Phase-Sensitive Track Circuit Based on BP Neural Network Optimized by Genetic Algorithm
Authors: Wang Xinkai
Published: December 2022

In this paper, considering the actual situation of the track circuit, aiming at the fault diagnosis of the 25Hz Phase-Sensitive track circuit, because the BP neural network (BPNN) model possess the characteristics of succinct construction and powerful nonlinear fitting ability as well as good fault tolerance performance, A fault diagnosis system of 25Hz Phase-Sensitive track circuit based on BPNN is designed. In addition, considering that the BPNN is greatly affected by the initial weight. Different results can be obtained when BPNN fault classifier is initialized with different weights, and it is easy to converge to the local minimum, so the genetic algorithm is selected to optimize the initial weight and threshold of the BPNN. The research results show that the BPNN optimized by genetic algorithm has fewer iteration steps, lower average error, higher classification accuracy, and is simple and easy to handle, which can better deal with nonlinear system problems such as track circuit fault diagnosis.
A Non-iterative Optimal Power Flow Calculation Method in Power System
Authors: Ren Yulun , Xu Shenkai , Liu Chengxi
Published: December 2022

The optimal power flow is very important in the study of power system, and it is of great significance for the economic operation of the power system to solve the active power output of the generator through the optimal power flow. In order to solve the problem that the traditional method is sensitive to the initial state and the large iteration times, this paper applies the holomorphic embedding method to solve the optimal power flow. By embedding holomorphic variables, the holomorphic embedding forms of constraints and KKT conditions are obtained. The power series coefficients of node voltage and generator active power output are calculated by non-iterative solution. Finally, the active power output of the generator is obtained by the method proposed in this paper, and then the lowest power generation cost of the system is calculated. Simulation results on IEEE study Case 3, Case 4, Case 30 and Case 39 verify the feasibility and accuracy of the proposed method.
Study on energy transition of dense particulate flow in a horizontal agitator
Authors: Hu Lei , Zhu Hongwu
Published: December 2022

Hammer mill cuttings cleaner is an efficient low-temperature drying cuttings equipment. In order to investigate the main components of energy dissipation and the flow characteristics of granular flow in grinding systems. The energy dissipation model of dense particle flow is established by numerical simulation and validated by macroscopic experiment. The results show that the particle flow mainly moves in a circle along the wall of cylindrical vessel. The main parts of energy dissipation are sliding friction consumption of particle, the inelastic collision between particles and sliding friction between particles and container; the input energy is a linear function of particle filling rate. The flat blade can provide higher efficiency at the same operational conditions. The study lays a theoretical foundation for the industrial application of Thermal-mechanical cuttings cleaner of drill cuttings and provides a reference for the optimization of blade configuration.
Influence of roll diameter configuration of 20 high mill on roll shifting control characteristics of wide titanium strip cold rolling
Authors: Zhou Guanyu , He Anrui , Liu Chao , Chen Luzhen , Qiang Yi , Liu Zhengqiao
Published: December 2022

In the production of wide titanium strips cold rolled by 20 high mill, when the diameter of the 1st intermediate roll is reduced, the work roll with a large roll diameter will be used to match it, which is called non-standard roll diameter configuration in this study. In order to master the control characteristics of the 1st intermediate roll shifting under non-standard roll diameter configuration, the coupled static model of roll system and strip is established by FEM, and the model is verified by using the corresponding relationship between the change of load roll gap and the change of titanium strip residual stress after cold rolling. The simulation results show that under the same rolling force, the contact stress peaks of non-standard roll diameter configuration in flat area and cone area of the 1st intermediate roll are about 1.44 times and 1.51 times of standard roll diameter configuration respectively. Compared with the standard roll diameter configuration, when the roll shifting amount increases, the longitudinal plastic strain of non-standard roll diameter increases most significantly in the range of 0-300mm from the titanium strip edge. Under the non-standard roll diameter configuration, increasing the roll shifting amount is more prone to occur the high-order buckle problem.
Principle, application and development trend of laser cleaning
Authors: Zhou Kan , Sang Shuguang , Wang Chengyu , Zhou Yihua
Published: December 2022

Many areas of industrial production are inseparable from cleaning technology, and traditional cleaning technology is increasingly unable to meet the requirements of modern industry. Laser cleaning technology is a new cleaning technology with high efficiency and no chemical pollution. It has the characteristics of non-contact, environmental protection, high efficiency, flexibility, energy saving and wide application range. Compared with mechanical friction cleaning, chemical corrosion cleaning, ultrasonic cleaning, dry ice cleaning and other technologies, it has obvious advantages. At present, laser cleaning technology has been widely used in the fields of aerospace body paint removal, cultural relics sample cleaning, mold and mechanical parts product cleaning, mainly used for paint treatment, rust removal, oil removal and particles. This paper discusses the development trend of laser cleaning technology compared with the traditional laser cleaning technology.
Aerodynamic simulation and analysis of large ring-sail parachute
Authors: Yang Dongyu , Feng Zhiwei , Huang Hao , Zhang Qingbin , Yang Tao
Published: December 2022

Parachutes have been closely linked to many space missions. Many vehicles launched into space have had parachutes on board for recovery or landing deceleration, and relative research mainly adopts computer simulation methods due to high test costs. In order to investigate the aerodynamic force and the surrounding flow field structure of the parachutes in the process of vehicle return, a physical model is established for the main parachute used in spacecraft return, using trimmed mesh for spatial division, and numerical simulations of the steady-state flow field of the large ring-sail parachute at different angles of attack are conducted. The results show that, the drag coefficient increases and then decreases, and the lift coefficient decreases and then increases with increasing angle of attack; the high-low-high-low-incoming flow velocity of the axial flow field generated by the ring-sail canopy is demonstrated and analyzed. The simulation results provide theoretical guidance for the structural design of the return parachute.
Calculation and influence analysis of tooth surface friction coefficient of planetary gear system in mixed lubrication condition
Authors: Yang Jin , Lin Tengjiao , Liu Wen
Published: December 2022

Based on the gearing theory, the calculation formulas of comprehensive curvature radius, relative sliding speed and tooth surface contact stress of internal and external meshing gear pair of the planetary gear system are deduced in this paper. Combined with load sharing theory and thermal elastohydrodynamic lubrication analysis method, the oil film thickness, film bearing ratio and friction coefficient are solved and the effects of roughness and input power on the friction coefficient are studied. The results show that with the increase of tooth surface roughness, the film bearing ratio decreases and friction coefficient increases; As the input power increases, the film temperature increases, the oil viscosity and film thickness decreases, which causes the tooth surface friction coefficient increases.
Torque Simulation and Analysis of Quadruped Robot under Trot Gait
Authors: Dong Xu , Meng Jian , Zhang Bin , Sun Zhizhou , Li Jian , Yang Shangwei
Published: December 2022

The quadruped robot can overcome the unevenness of the wheeled chassis on steps and gravel roads, and has good passability. The Trot gait is the basic gait of the quadruped robot, and the walking is realized by the gait of alternating footsteps. In this paper, the dynamic simulation of the static equilibrium state of the quadruped robot in different poses on the ground and stair is carried out, and the movement of the robot body under the trot gait is simulated to obtain the joint torques of the upper and lower leg of the quadruped robot, which is the driving torque of the joint motor. The model selection provides a theoretical basis, and at the same time, the motion analysis of the quadruped robot is carried out, and the moving distance of the chassis under the extreme posture is planned.
Outlier elimination method of GPS data points based on Hough transform
Authors: Dong Yu , Shuai Qi , Qin Feifei
Published: December 2022

The electronic map of railway track can realize the monitoring and evaluation of line status, so as to reduce the workload of manual operation. In order to improve the fitting accuracy of the existing railway track electronic map, the measured data of the railway line are obtained by Global Positioning System (GPS), and the Gaussian coordinates of the measured data points are obtained through coordinate transformation. Based on the analysis of GPS data, the Hough transform is improved to eliminate the outliers in the straight track and curved track scenarios respectively. With the help of the idea of taking the average value of multiple measurements to eliminate errors, the processed data are corrected and the track line is fitted. The results show that the track route electronic map generated by the outlier elimination method based on Hough transform has high accuracy and has important practical significance and practical application value.
Design of vision recognition system for picking robots
Authors: Yu Jianyong , Zhao Dejin
Published: December 2022

Based on yolov4-tiny deep learning neural network, an improved yolov4-tiny network model is proposed in order to achieve the reduction of the network model for overlapping fruits and branch-obscured fruits in natural environment and to realize the accurate and fast recognition of apple-pear fruits, the main improvement measures include: firstly, the CSPBlock residual network module of the backbone network is introduced in the module of the backbone network to replace the 3×3 convolution kernel in it, which improves the perceptual field of the feature layer in the network and enhances the extraction capability of the target feature information through the spatial consistency and channel specificity of the Involution operator. second, the output of the first layer of the CSPBlock module in the backbone network containing the rich surface information of the image is extracted in the feature pyramid with the first and second scale feature maps for multi-scale feature fusion to enhance the extraction capability of dense small target feature information, by conducting training experiments on the apple pear dataset collected by ourselves, the experimental results show that the accuracy of the improved network structure is 95.45%, an improvement of 2.84%, and the recall rate is 94.92%, an improvement of 2.83%, compared with yolov4-tiny, the improved method improves the accuracy of fruit recognition and provides the theoretical basis for the subsequent apple pear picking robot to quickly identify picked apple-pears.
A fast simulation method for magnetically driven deformation of a sheet micro soft robot
Authors: Gao Jian , Rong Weibin , Gao Peng , Li Dongjie , Wang Lefeng
Published: December 2022

The magnetically driven micro soft robot is a hot research topic in the field of micro robotics. The magnetic torque of each part of the robot rotates with its deformation, so the magnetic torque and magnetic force to which the robot is subjected are difficult to be calculated directly. The lack of physical interfaces for torque distribution in many finite element software reduces the speed and accuracy of calculating the deformation of a robot using finite element simulation methods. In this paper, a fast simulation method to convert the local magnetic torque into equivalent load density for the deformation mode of the sheet micro soft robot is proposed. A finite element model of the fabricated micro soft robot is established, and the deformation and total magnetic moment of the robot under different magnetic field strength and magnetic field gradient are simulated and calculated. Experiments are executed to verify the validity of the simulation results.
Experimental Study of an Engineering Prediction Approach for Shipboard Cabin Noise
Authors: Li Yaofei , Jiang Shiliang , Feng Shaodong , Cao Weiwu , Zhang Kai
Published: December 2022

At present, the prediction of shipboard cabin noise is mainly obtained by simulation calculation using FEM, BEM or SEA. These methods are not convenient for rapid engineering prediction. By making a test platform of shipboard cabin noise prediction, we make an experimental study of a simplified engineering prediction approach for shipboard cabin noise based on Source-Path-Receiver system approach. The experimental study shows that this approach is feasible and valid when applied to predict air borne noise level in a sound source shipboard cabin.
Defect identification method of macrostructure crack based on position information feature
Authors: Wang Yuhan , He Qing
Published: December 2022

A method for the recognition of macrostructure crack defects based on feature position information is proposed. Establish a deep learning module based on the UNet network, which includes spatial location information. According to the location information of different crack defects, add the spatial information extraction module behind the convolution layer. The defect location feature information and up sampling feature information are fusion, recognition of crack defects with different macrostructures by network training. This method realizes the automatic recognition of crack defects, reduces the labor intensity and improves the recognition efficiency.
Mobile robot quasi-stop method based on sliding mode control
Authors: Sun Xuan , Liu Xijun , Zhang Baixing
Published: December 2022

In this paper, the sliding mode control algorithm is designed for the deceleration curve tracking problem that affects the quasi-stop of mobile robot, and the tracking performance of the sliding mode control algorithm and PID control algorithm is simulated and analyzed in MATLAB. Through comparison, it is verified that the designed sliding mode control algorithm has better tracking performance. Finally, the parking error of the mobile robot is tested by experiments, which proves that the sliding mode control can effectively improve the quasi-stop accuracy of the mobile robot.
Research on noise suppression of imaging data by optimized least squares reverse time migration method
Authors: Li Rui , Zhang Xiaodan , Gou Haiyang , Liu Dongxiao , Xv Kemeng , Wu Zepeng , Bai Zitong
Published: December 2022

Least squares reverse time migration imaging is an imaging theory based on the accurate description of geological structures by seismic waves, which can greatly improve the detection accuracy. In the complex environment of deep region, the influence of noise on the imaging resolution of reverse time migration is particularly significant. In this paper, an optimized least squares reverse time migration imaging method with better amplitude fidelity and higher imaging accuracy is proposed. This method suppresses the noise interference by reducing the residual value between the inversion data and the actual data. The experimental results in the paper show that the optimized least squares reverse time migration can achieve high accuracy and high resolution imaging, especially in the deep region. This method is effective and feasible.
Analysis of dynamic fatigue characteristics of critical parts of highly strengthened single cylinder diesel engine
Authors: Wang Guixin , Cao Yilong , Zhu Jialing , Yu Qiang
Published: December 2022

In this paper, the strength analysis and fatigue life calculation of multi-component coupling of crankshaft, connecting rod and engine body of highly strengthened single cylinder diesel engine are carried out. The stress of crankshaft, connecting rod and engine body in two working cycles is calculated by multi-component coupling transient dynamics, and the strength is analyzed based on the third strength theory firstly; Then, the accuracy of the transient calculation results is verified by the strength experiment of the crankshaft and connecting rod reduced scale model and the calculation of the static stress of the body; Finally, according to the stress fatigue life calculation method, the fatigue life of crankshaft, connecting rod and engine body is calculated. The maximum stress of crankshaft, connecting rod and body is less than the yield limit of corresponding materials; The fatigue life calculation results show that the damage accumulation of the engine body is very little, which meets the design requirements of infinite life. The damage accumulation of the crankshaft at the fillet of the main journal and the connecting rod at the side of the rod is 32005.6 hours and 102841.7 hours respectively, which meeting the design requirements of 20000 hours.
Microstructural and Mechanical Characteristics of 7075-T6 Aluminum Alloy Joint by Double Wire Pulsed Cold Metal Transition Welding
Authors: Zhang Zehua , Li Xiaoqiang , Zhu Dezhi , Qu Shengguan
Published: December 2022

In order to solve the problems of low joint strength and poor welding efficiency in fusion welding of 7075-T6 aluminum alloy, the double wire pulsed cold metal transition (DW-CMTP) welding method was used to weld 7075-T6 aluminum alloy. The microstructural and mechanical characteristics of the joints were analyzed by energy dispersive spectroscopy (EDS), scanning electron microscopy (SEM), tensile test and Vickers hardness measurement. The results showed that the DW-CMTP welded joints had good mechanical properties. The highest tensile strength of the joint is 320 MPa without post-weld heat treatment, reaching up to 63% of the basic material. The presence and distribution of micropores in weld joint were manipulate by welding parameters and weakened the joint strength. The fracture location transferred from the heat-affected zone to the fusion zone with the increase of heat input, owing to the change of pore distribution.
Research on propagation delay correction method based on scaled model of enhanced Loran transmitting antenna
Authors: Hu Zhaopeng , Yang Fan
Published: December 2022

The enhanced Loran signal transmits the signal through the atmospheric channel. Considering the obstacles and other factors, the radio wave will be affected by path loss, shadow fading and multipath fading. Therefore, the signal power at different distances from the transmitting point is different. The scaled model antenna is used to transmit and receive the enhanced Loran signal, and the Loran receiver is used to receive. According to the different power of the received signal of the receiver, the signal propagation distance can be deduced by using the correlation model, so as to correct the path delay, that is, the timing accuracy can be improved.
Finite element analysis and structural optimization of V-shaped seal ring based on ANSYS Workbench
Authors: Guo Zhounan , Li Hui , Gu Chang
Published: December 2022

Based on the finite element analysis software of ANSYS Workbench, the sealing performance of a V-shaped seal ring is analyzed. It is found that the position of the maximum shear stress of the V-shaped seal ring is on both sides of the bottom of the opening. Then, the effects of root height h and opening arc diameter D on the maximum shear stress and maximum contact pressure of the seal ring are studied, and the parameters are optimized accordingly. Further, the ultimate working pressure of the optimized structure is analyzed. The results show that the maximum shear stress and maximum contact pressure of the seal ring increase with the root height, but there is a downward inflection point at h-0.2. The maximum shear stress of the seal ring increases with the opening arc diameter, but there is a rising inflection point at D-0.2. Further, the maximum contact pressure of the seal ring first increases rapidly and then increases slowly with the opening diameter. The working oil pressure that the V-shaped seal ring can bear is 1.3 MPa. The simulation results can guide the design of the V-shaped seal ring.
Study on high temperature mechanical properties of niobium microalloyed cold heading steel
Authors: Chen Jilin , Feng Guanghong , Ma Jian , Lin Peng , Yang Dong , Ma Honglei
Published: December 2022

In recent years, high-strength micro-alloyed cold heading steel has developed rapidly, mainly by adding Nb, V, Ti and other micro-alloying elements to the steel for grain refinement and precipitation strengthening, it is widely used in automobiles, bridges, construction machinery and other fields due to its excellent strength and toughness, fatigue resistance and corrosion resistance. However, the common quality defects in the process of continuous casting and hot rolling of such steels - transverse cracks on the surface and corners, are still one of the technical difficulties in the production of the world’s iron and steel enterprises. Therefore, it is of great scientific and engineering significance to deeply explore the evolution law of high temperature mechanical properties of niobium microalloyed cold heading steel, to analyze the common generation mechanism of surface transverse cracks and to propose general improvement measures. In this work, the high temperature thermoplastic properties of niobium microalloyed cold heading steel was studied by using Gleeble-3500 thermal simulator, combined with optical microscope (OM) and scanning electron microscope (SEM), the tensile fracture morphology and nearby microstructure were observed, and its high temperature plasticity mechanism was analyzed. The results show that the niobium microalloyed cold heading steel has two brittle temperature ranges: the first brittle zone is from the melting point to 1200°C, the temperature range of the third brittle zone is below 700°C, and the optimum plasticity zone is 700-1200°C. At 650°C, the fracture mode is ductile fracture and cleavage fracture; at 800°C, it is a typical cleavage-brittle fracture type; at 950°C, the fracture mode is dimple fracture, with good plasticity; at 1100°C, the particles become finer and the plastic deformation is more uniform. In order to avoid the occurrence of cracks in the continuous casting billet, the straightening temperature of the continuous casting billet should be higher than 700°C, it should be heated slowly in the early stage of heating, and the hot rolling temperature should be controlled at 700-1100°C.
Study on torsion of PVC part formed by incremental sheet forming
Authors: Zhang Xitang , Wang Jin , Zhang Xiaobo
Published: December 2022

The development of plastic product prototype by incremental sheet forming (ISF) has attracted extensive attention. Forming polyvinyl chloride (PVC) sheet into parts by ISF has a wide application prospect in many industrial fields. However, torsion is a problem that needs to be solved. In this paper, some truncated pyramids were formed by different feed speeds and tool paths with a certain spindle speed of the tool. Torsion angle of central line and accuracy of each formed part were measured. In addition, numerical simulation was also used to get the influence of tool path on the torsion of PVC parts. The results show that PVC part appears torsion around the central axis when it was formed by the unidirectional direction tool path, and torsion increases and accuracy reduces with increment of feed speed of the tool. Otherwise, the alternating bidirectional direction tool path can effectively eliminate the torsion of PVC part.
Investigation of microstructures and properties of graphene reinforced 20CrMnTi materials
Authors: Lu Xiaogang , Li Yongsheng , Meng Zhongwen , Chen Yunbo
Published: December 2022

As a member of low-carbon alloy steels, 20CrMnTi has been widely used to manufacture key-parts, such as gears and shafts, owing to its attractive fatigue resistance and easy of processing. To improve its the mechanical and frictional properties, the preparation of composite is required. In the present study, graphene was added in 20CrMnTi to form Gr/20CrMnTi composites by vacuum high-energy ball milling process and hot-pressing technique. The addition of graphene has a profound influence on the microstructure and properties of 20CrMnTi. A high hardness of 5.83 GPa and a good tensile strength of 1183 MPa were obtained in the 0.5 wt.%-Gr/20CrMnTi, increased by 18.5% and 27.8%, respectively. Meanwhile, the wear resistance reaches a maximum value of 2276.5 cm-3 in the 0.7 wt.%-Gr/20CrMnTi, showing a 491.1% increase than that of pure 20CrMnTi. The layered graphene played an important role in absorbing energy and preventing the propagation of micro-crack.
Meta-analysis of the influence of different element contents on selecting the prediction model of gray cast iron’s elastic modulus
Authors: Hu Chunyang , Liu Qi , Du Yutong , Zhang Junjia , Jiang Ou , Che Fei
Published: December 2022

In order to explore the influence of different element contents on selecting the prediction model of gray cast iron’s modulus, we apply Meta-analysis to retrieve Chinese journals related to gray cast iron and elastic modulus and adopt fixed effect models to evaluate and analyze the introducedδ value, hoping to provide theoretical basis for prediction model of elastic modulus. According to the analytical results: (1) When the silicon content is relatively low, the model E0=101.32+2.51Si/C is suggested for prediction. (2) When the carbon content is relatively low, the model E0=313.175-49.014C-14.082Si is suggested for prediction. (3) When the two elements are both relatively low, Si/C value-based judgment needs to be made that the model E0=101.32+2.51Si/C is suggested when the value is relatively low. (4) When either the silicon content or the CE (carbon equivalent) is relatively low, the model E0=194.55-27.85CE+58.2Si/C or the model with three variables-E0=20.527-0.021Si/C+59.2841Si+0.004CE is suggested for prediction. (5) When some of the above cases exist simultaneously, the preferable model selection should be considered in the following order of priority: C=Si>Si/C>CE>S.
Modification of graphene and its effect on anticorrosive properties of coatings
Authors: Chen Qiang , Yuan Guo , Zhao Yueju , Guo Miao , Peng Weimin , Zhen Yongli , Shi Jinbiao , Xie Xiwei , Zhao Chunfeng
Published: December 2022

In this paper, zinc particles were grafted on the surface of graphene by KH550. It was proved that zinc powder was successfully connected to the surface of graphene by KH550 through IR, SEM, energy spectrum and thermogravimetric analysis. The modified graphene is added to the anti-corrosion coating, which effectively improves the anti-corrosion performance of the coating.
Effect of TiO2addition on phase stability and sintering behavior of 1 mol%La2O3-2 mol%Gd2O3-2 mol%Yb2O3-6 mol%Y2O3co-doped ZrO2
Authors: Li Li , Lei Xingeng , Wang Quansheng , Zhao Hanqi , Ning Xianjin
Published: December 2022

In this study, 1 mol%La2O3-2 mol%Gd2O3-2 mol%Yb2O3-6 mol%Y2O3co-doped ZrO2(LGYYSZ) with 0 mol%, 5 mol% and 10 mol% TiO2additions were synthesised by solid-state reactions. The effect of TiO2addition on the phase stability of LGYYSZ and its sintering behaviour at 1500 °C were investigated using XRD, SEM and EDS. The results show that the eutectic temperature of LGYYSZ decreases with increasing TiO2content. SEM, EDS and XRD results show that the TiO2addition is reacted with the La2O3in LGYYSZ to form a orthorhombic La2Ti2O7phase. When held at 1500 °C, La2Ti2O7is precipitated on the surface of the samples by evaporation-condensation mechanism. This resulted in the anti-sintering properties of LGYYSZ at 1500 °C decreasing with increasing TiO2content.
Numerical simulation of thermal properties of cubic period metal foam embedded graphene-aerogel composite PCM
Authors: Pan Changyu , He Ping , Shi Enqi
Published: December 2022

In the context of green and clean energy, latent heat energy storage by phase change materials is considered as one of the important energy technologies. In this paper, a new metal foam embedded graphene aerogel composite phase change material is developed, and pore-scale numerical simulations are performed in order to investigate the thermal properties of this composite phase change material. Among them, this paper designs copper foam with cubic periodic unit structure, which not only has high thermal conductivity, high porous structure and low relative density, but also can be rapidly fabricated by new fabrication techniques, while paraffin and erythritol are selected as PCM embedded in the metal foam. By analyzing the temperature-time and liquid phase-time relationship graphs, it is known that the new composite phase change material has more uniform internal temperature distribution and shorter melt condensation time compared to graphene-aerogel composite PCM, which provides a method for thermal management of PCMs.
Double diaphragm forming simulation for net-shape component using multi-layered biaxial non-crimp fabrics
Authors: Yu Fei , Chen Xiangming , Chen Shuai
Published: December 2022

Compared to autoclave-cured prepreg, liquid composite moulding (LCM) is a cost-effective alternative to produce advanced composites, thanks to the less-expensive intermediate materials, lower capital investment and shorter cycle time. A separate preforming step is typically required within the process chain to convert 2D fabric blanks into complex 3D geometries before moulding. Numerical models are therefore important to ensure near net-shape preforms during the design phase, in order to minimise the material wastage related to preforming. In this study, a microscale finite element (FE) model was employed to assist in determining the ply shape of multi-ply biaxial non-crimp fabrics (NCF) to achieve net-shape preforms made by double diaphragm forming (DDF) using a spar-like geometry. The forming deformation of the NCF was predicted by simulations considering the in-plane stiffness of the NCF. The location of wrinkles was indicated by the simulation using membrane elements. By continuously removing the redundant fabric material making contact with the machine bed and tool surface, net-shape preforms were achieved for the target geometry using single and multiple NCF plies respectively. Compared with the original ply shape, the number of wrinkles was reduced for the net-shape case due to the reduction in the bridging force induced by the contact pairing between fabric-diaphragm assembly and the machine bed.
A novel superhydrophobic Ni-graphene coating and its corrosion resistance
Authors: Zhang Ruiyu , Liu Jianguo , Li Zili , Cui Gan
Published: December 2022

A novel superhydrophobic Ni-graphene coating is synthesized on mild steel by one-step electrodeposition. The microtopography and contact angle of coatings deposited at varied deposition conditions were investigated to obtain the optimized preparation parameters. The anti-corrosion performance of the coatings was investigated by electrochemical polarization in synthetic seawater. The results illustrate that the Ni-graphene coatings deposited at GO concentration of 0.2 g·L–1 and current density of 4 A·dm–2 possessed dual roughness structures. After stored for 14 days in a vacuum drying chamber, the coating exhibited a contact angle of 156.1° and a sliding angle of 6.2°. Furthermore, the corrosion current density of the superhydrophobic coating was only 2.3×10–8 A·cm–2. This facilely prepared fluorine-free Ni-graphene superhydrophobic coating can potentially provide a pathway for corrosion control in the oil and gas industry.
Optimization of Aluminum Alloy Rifled Barrel ECM Process Parameters Based on GA-BP Algorithm
Authors: Zheng Yaze , Tang Lin , Liu Shiying , Zhou Jiakai
Published: December 2022

Electrochemical machining process parameters will affect the surface integrity, surface roughness, service life and other properties of the workpiece. In order to realize high-efficiency and high-quality ECM of aluminum alloy rifled barrel, a method of process parameter optimization based on GA-BP neural network is proposed. The model of BP neural network is established by using MATLAB software. Machining clearance and surface roughness are objective functions. The MSE and linear regression value are analyzed. Genetic algorithm is used to optimize the connection weight and output threshold of BP neural network model. The change of fitness function and the error between predicted value and actual machining value are analyzed. The results show that the GA-BP neural network model can better predict the objective function. The optimal parameters of aluminum alloy rifled barrel ECM are: electrolyte temperature of 29.5±0.2 °C, electrolyte inlet pressure of 1.23±0.02 MPa, power supply voltage of 8.4±0.1 V, and working current of 3600±50 A.
Effect of oxygen pressure on the properties of n-type cuprous oxide films prepared by pulsed laser deposition
Authors: Fan Tianyao , Wang Xianghu , You Hongyu , Luo Jianren , Zhang Rulin , Li Rongbin , Jin Min , Jiang Chunxia , Wang Mengbo , Yang Ziwen , Liu Xiaotong , Zhang Xinlei
Published: December 2022

The quality of the n-type cuprous oxide film is the key to improving the conversion efficiency of the cuprous oxide homojunction solar thin film battery, and its preparation is very difficult. In this paper, pulsed laser deposition (PLD) was used to stably prepare n-type Cu2O films on (0001) sapphire (c-Al2O3) substrates, and the influence of the oxygen pressure in the chamber on the structure and electrical properties of the films was studied in detail. The measurments of X-ray diffractometer, scanning electron microscope, atomic force microscope, and Hall effect show that the Cu2O films exhibited n-type conductivity uder the oxygen pressure of 0.5, 1, 2, and 5 Pa, respectively. At the same time, the film under the oxygen pressure of 0.5 Pa produce the best crystal quality and electrical properties of an electron concentration of 2.753×1011cm-3and mobility of 19.76cm2/vs.
Solid-phase preparation of defective carbon supported PtNi alloy electrocatalyst and analysis of its oxygen reduction mechanism
Authors: Wang Zhaoxi , Chen Yanli , Yan Wei , Cheng Yuanzhuang
Published: December 2022

In the present work, PtNi-loaded defective carbon (Pt/ZnPPC) was prepared by solid-phase method. Carbon support with specific defect types, such as Zn metal nitrogen carbon (ZnPPC850), N-doped carbon (ZnPPC950) and defective carbon (ZnPPC1050), were selectively obtained by optimizing the pyrolysis temperature to explore the effect of defect types on oxygen reduction reactions (ORR). Electrochemical measurements showed that the half-wave potential of the PtNi metal nanoparticle-loaded ZnPPC1050 catalyst (PtNi-ZnPPC1050) outperformed the commercial JM-Pt/C by 35 mV, and by 45 mV compared to the PtNi-loaded ZnPPC950 catalyst (PtNi-ZnPPC950), suggesting that the defects in the ZnPPC1050 support resulting from the evaporation of N by pyrolysis can interact well with Pt metal electrically, allowing the PtNi nanoparticles to be uniformly distributed. Meanwhile, the defects lead to the carrier containing a large number of active sites making its catalytic performance even much better than the pyridine nitrogen sites in ZnPPC950. The carbon defect structure is loosened and porous with high specific surface area, which can effectively load PtNi nanoparticles and enhance the mass transfer. We obtained a new bimetallic oxygen reduction catalyst loaded with PtNi on defective carbon and elucidated the effect of five-membered ring carbon defect structure and N-doped structure on metal-carrier interaction.