bluuebunny/crossref_metadata_2025 huggingface dataset:
GaAs surface passivation for InAs/GaAs quantum dot based nanophotonic devices
Authors: Chellu Abhiroop , Koivusalo Eero , Raappana Marianna , Ranta Sanna , Polojärvi Ville , Tukiainen Antti , Lahtonen Kimmo , Saari Jesse , Valden Mika , Seppänen Heli , Lipsanen Harri , Guina Mircea , Hakkarainen Teemu
Published: December 2020

Several passivation techniques are developed and compared in terms of their ability to preserve the optical properties of close-to-surface InAs/GaAs quantum dots (QDs). In particular, the influence of N-passivation by hydrazine chemical treatment, N-passivation by hydrazine followed by atomic layer deposition (ALD) of AlO
x
and use of AlN
x
deposited by plasma-enhanced ALD are reported. The effectiveness of the passivation is benchmarked by measuring the emission linewidths and decay rates of photo-carriers for the near-surface QDs. All three passivation mechanisms resulted in reducing the oxidation of Ga and As atoms at the GaAs surface and consequently in enhancing the room-temperature photoluminescence (PL) intensity. However, long-term stability of the passivation effect is exhibited only by the hydrazine + AlO
x
process and more significantly by the AlN
x
method. Moreover, in contrast to the results obtained from hydrazine-based methods, the AlN
x
passivation strongly reduces the spectral diffusion of the QD exciton lines caused by charge fluctuations at the GaAs surface. The AlN
x
passivation is found to reduce the surface recombination velocity by three orders of magnitude (corresponding to an increase of room-temperature PL signal by ∼1030 times). The reduction of surface recombination velocity is demonstrated on surface-sensitive GaAs (100) and the passivating effect is stable for more than one year. This effective method of passivation, coupled with its stability in time, is extremely promising for practical device applications such as quantum light sources based on InAs/GaAs QDs positioned in small-volume photonic cavities and hence in the proximity of GaAs-air interface.
New concept of metal ion thruster based on pulsed thermionic vacuum arc discharge
Authors: Velicu I-L , Tiron V , Petrea M-A , Popa G
Published: December 2020

A new approach for the development of an innovative, low-cost, long lifespan, small size and versatile metal ion thruster (MIT), able to independently control thrust and specific impulse generation, is proposed. The concept of pulsed thermionic vacuum arc (PTVA) is used to generate and accelerate metal ions, without using acceleration grids. Operating under high or ultra-high vacuum conditions makes PTVA discharge suitable to be used in the vacuum of space. The proposed electric propulsion system can provide significant thrust and specific impulse levels due to an efficient metal ion acceleration process in the electric field of a double layer structure developed in PTVA plasma. For certain experimental conditions, the performance parameters values of this MIT–PTVA approach, and even exceed, those of the classical ion thrusters like xenon ion propulsion system and stationary plasma Hall thruster.
Optical estimation of unitary Gaussian processes without phase reference using Fock states
Authors: Oh Changhun , Park Kimin , Filip Radim , Jeong Hyunseok , Marek Petr
Published: December 2020

Since a general Gaussian process is phase-sensitive, a stable phase reference is required to take advantage of this feature. When the reference is missing, either due to the volatile nature of the measured sample or the measurement’s technical limitations, the resulting process appears as random in phase. Under this condition, we consider two single-mode Gaussian processes, displacement and squeezing. We show that these two can be efficiently estimated using photon number states and photon number resolving detectors. For separate estimation of displacement and squeezing, the practical estimation errors for hundreds of probes’ ensembles can saturate the Cramér–Rao bound even for arbitrary small values of the estimated parameters and under realistic losses. The estimation of displacement with Fock states always outperforms estimation using Gaussian states with equivalent energy and optimal measurement. For estimation of squeezing, Fock states outperform Gaussian methods, but only when their energy is large enough. Finally, we show that Fock states can also be used to estimate the displacement and the squeezing simultaneously.
Roadmap for the multiscale coupling of biochemical and mechanical signals during development
Authors: Lenne Pierre-François , Munro Edwin , Heemskerk Idse , Warmflash Aryeh , Bocanegra-Moreno Laura , Kishi Kasumi , Kicheva Anna , Long Yuchen , Fruleux Antoine , Boudaoud Arezki , Saunders Timothy E , Caldarelli Paolo , Michaut Arthur , Gros Jerome , Maroudas-Sacks Yonit , Keren Kinneret , Hannezo Edouard , Gartner Zev J , Stormo Benjamin , Gladfelter Amy , Rodrigues Alan , Shyer Amy , Minc Nicolas , Maître Jean-Léon , Di Talia Stefano , Khamaisi Bassma , Sprinzak David , Tlili Sham
Published: December 2020

The way in which interactions between mechanics and biochemistry lead to the emergence of complex cell and tissue organization is an old question that has recently attracted renewed interest from biologists, physicists, mathematicians and computer scientists. Rapid advances in optical physics, microscopy and computational image analysis have greatly enhanced our ability to observe and quantify spatiotemporal patterns of signalling, force generation, deformation, and flow in living cells and tissues. Powerful new tools for genetic, biophysical and optogenetic manipulation are allowing us to perturb the underlying machinery that generates these patterns in increasingly sophisticated ways. Rapid advances in theory and computing have made it possible to construct predictive models that describe how cell and tissue organization and dynamics emerge from the local coupling of biochemistry and mechanics. Together, these advances have opened up a wealth of new opportunities to explore how mechanochemical patterning shapes organismal development. In this roadmap, we present a series of forward-looking case studies on mechanochemical patterning in development, written by scientists working at the interface between the physical and biological sciences, and covering a wide range of spatial and temporal scales, organisms, and modes of development. Together, these contributions highlight the many ways in which the dynamic coupling of mechanics and biochemistry shapes biological dynamics: from mechanoenzymes that sense force to tune their activity and motor output, to collectives of cells in tissues that flow and redistribute biochemical signals during development.
Research on ultrasonic phased array inspection technology of small diameter tube based on Ultravision simulation technology
Authors: Gao Yunpeng , Wang Xu , Xie Liming , Gong Weiwei
Published: December 2020

According to the principle of ultrasonic phased array inspection, the ultrasonic phased array inspection simulation experiment is carried out on the butt weld of small diameter tube of power plant boiler by using the Ultravision software, which mainly includes the simulation of acoustic beam coverage and focused beam distribution. From the simulation test results, it can be concluded that: through the simulation of the acoustic beam coverage, the accessibility and coverage of the ultrasonic phased array acoustic beam can be simulated, and the applicability of the detection process can be verified and optimized; Through the simulation of focusing beam distribution, the distribution of the beam focus in the butt weld of the small diameter tube can be determined, which can guide the selection of focusing mode in the detection process and improve the signal-to-noise ratio of defect detection.
Research on Measuring Method of RVSM Regional Waviness
Authors: Ru Wang
Published: December 2020

The increased accuracy of RVSM (Reduced Vertical Separation Minimum) can increase the flight level and airspace capacity of the aircraft, optimize the route, improve the operational efficiency of the aircraft, and improve the operating efficiency of the airline. The skin waviness near the aircraft’s full static pressure probe has an important effect on RVSM. This article mainly studies several methods that can be used to measure the aircraft skin waviness, including advanced optical methods and spline curve method based on field work experience. In addition, the article also compares the advantages and disadvantages of these methods.
Different Techniques of Producing Superconducting Joints and Methods of Joints Characterization
Authors: Tan Weilun
Published: December 2020

In this paper, the method of producing superconducting joint will be briefly discussed. Cold press welding method, ultrasonic welding, spot welding and Thornton’s replacement method will be discussed. The characteristics of the superconducting joint are also discussed by using four probe method and IRT method.
Design and Implementation of FOD Detector for Airport Runway
Authors: Yuan Zhong-Da , Huang Guang-Hong , Liu Ming-He , Zhang Yong
Published: December 2020

Safety is the eternal theme of civil aviation. The flight safety of domestic civil aircraft affects the hearts of millions of people. Among the many factors that affect the flight safety of aircraft, foreign objects on the airport runway play an important role. Every year, there are many cases to remind us to guard against the significant impact of FOD on the flight safety of aircraft. In terms of FOD protection, China is still in the stage of artificial detection. On the one hand, it causes huge waste of human resources; on the other hand, it increases the probability of human error and seriously affects the flight safety of aircraft. Therefore, the current technological means can be used to detect FOD, so as to reduce the inspection omission caused by human error and protect the flight safety of the aircraft.
Structural Design and Simulation of Linear Motion Device
Authors: Sun Xuefeng , Zhao Zhe
Published: December 2020

Linear motion device is widely used in various industries. In this paper, a linear motion device design method is proposed for the test system with large load mass, large impact velocity and short acceleration time.

According to this paper, the design of linear motion device is explicated, the structure of linear motion device is described, and the working principle is stated. Also, the three-dimensional model design of the components in linear moving device is carried out based on UG, and the sub-structure is illuminated. The finite element simulation analysis of each part in the catapult device is carried out based on Nastran. Conclusively, the structural deformation and stress of each part of the linear motion device are obtained, verifying the feasibility of linear motion device structure design.
Effect of heat treatment on property and residual stress of cold drawn tube
Authors: Wen Jun , Fan Huiji , Jin Xin , Tang Cai
Published: December 2020

The change of strength, toughness and residual stress of Q690 cold-drawn tube were studied under (400˜;600)°C and heat preservation (1-3)h heat treatment. With the increase of temperature and the extension of the holding time, the strength and residual stress of the cold drawn tube gradually decreased, and the impact toughness increased first and then decreased. When holding at 550 °C for 2 hours, the impact toughness reached the highest 34.6J;the mechanical properties of cold drawn tubes were mainly affected by the reduction of internal stress and grain deformation caused by heat treatment.
Design of Vehicle Charger for Pure Electric Vehicle Based on MATLAB Simulation
Authors: Zhu Xiaqing , Kong Lingyu , Yang Xinjun , Xu Ya
Published: December 2020

In this paper, the basic principle of the on-board charger of electric vehicle is studied and analyzed, and the design scheme of vehicle charger with two-stage transformation structure is proposed. The former converter adopts boost active power factor correction circuit to improve power factor and reduce total harmonic distortion; the latter adopts phase shifted full bridge ZVS inverter circuit to realize electrical isolation and DC / DC conversion. According to this scheme, a 2kW vehicle charger is designed. The charging mode adopts three-stage charging method to charge lithium battery pack, and the three-stage charging is simulated. The results are consistent with the requirements of three-stage charging curve.
IGBT Heat Dissipation Design and Optimization
Authors: Fan Xinyu , Cui Hongjiang , Xu Yongsui
Published: December 2020

The reliable operation of IGBT (insulated gate bipolar transistor) is the key to the performance of motor control system, which directly affects the performance of the vehicle. By contacting with the surface of the radiator, the heat device rapidly transfers heat to the fin, which is then absorbed by the high-speed airflow between the fins and taken away to form a cooling channel to ensure that the heat device is always at an appropriate temperature during work. The power loss of IGBT under rated working conditions was estimated theoretically. The temperature field of the radiator under typical working conditions was simulated by ICEPAK, and the radiator was parameterized. The simulation results show that under the condition of forced cooling and heat dissipation, the optimized radiator meets the heat dissipation requirements of the motor controller.
Design and Analysis of FSC Formula Racing Car Body
Authors: Chen Ying , Zhou Jing , Su Gang , Wang Chunpeng
Published: December 2020

This article satisfies the design rules of the FSC College Student Formula Contest. Based on the existing frame and other relevant data, CATIA and Profili are used to select the airfoil, and draw the three-dimensional model of the body shape and aerodynamic kit A simplified model of a racing car. Using ANSYS Geometry, ICEM-CFD and fluent modules, after setting the boundary conditions, the front wing and tail wing are simulated and analyzed respectively, and the stress of the selected model and the air flow around the car are checked through fluent post-processing. Using the data shown as a reference, the simulation data of each group of car equipped with front and rear wings was analyzed to determine the design of the front and rear wings. The flow field analysis is performed on the vehicle after the selected empty set is installed, and the result is obtained, compared with the data before the installation, and a conclusion is drawn.
Study on the Determination Method of the Adsorption of Water Reducer on Cement Surface Based on Total Organic Carbon Analyzer
Authors: Wu Chuan-Deng , Shao You-Zhe , Li Ge-Li , Fang Yun-Hui
Published: December 2020

At present, most of the methods for testing the amount of Water-reducing admixture adsorbed on the surface of the cement particles use the total organic carbon method (TOC method), but various literatures describe the pre-treatment of the test method as ambiguous and poor operability. In view of the above problems, this paper carried out a study on the pre-treatment conditions of the test for the adsorption of Water-reducing admixture on the surface of cement particles by total organic carbon method, and explored the effects of stirring time, standing time, and standing temperature on the adsorption of Water-reducing admixture on the surface of cement particles. The study determined the pre-treatment and test conditions of the TOC method, and provided reference for the research on the adsorption behavior of the water reducer on the surface of cement particles. The correlation coefficients of the standard curve of Water-reducing admixture obtained by this method are all greater than 0.999, the relative error of the results of the 10 parallel experiments of the method is less than 0.005%, and the relative standard deviation (RSD) is 0.7706%.
Soft Measurement of Intelligent Vehicle side-slip Angle Based on Extended Kalman Filter*
Authors: Wang Yanxia , Wang Jianfeng , Yu Qiqi
Published: December 2020

A soft measurement method based on extended Kalman filter is proposed for the measurement of Intelligent Vehicle CG Side-slip Angle. Firstly, the nonlinear dynamic state model of intelligent vehicle is established, the state equation of Side-slip Angle is determined, and the extended Kalman soft measurement method is used for analysis. Secondly,through the establishment of a real vehicle test system, the soft measurement method of Side-slip Angle is verified under two working conditions and different vehicle speeds on the actual road. The test results show that the extended Kalman soft measurement method is reliable and accurate. The extended Kalman soft measurement method can meet the requirements of the full vehicle control system, and it has a certain value of full vehicle application research.
Effect of design parameters of custom abutment on its mechanical property based on orthogonal experiment method
Authors: Zhang Xiao , Zhang Jinyang , Chen Xianshuai , Feng Wei
Published: December 2020

In this paper, the custom abutment with various gingival morphology was designed by CAD software. The finite element analysis (FEA) and orthogonal experiments design L25 (56) were performed to investigate the influence of main design parameters of custom abutment on biomechanical property of implant system, including gingival height (GH), abutment angle (A), lingual height (LH), buccal height (BH), mesial height (MH) and distal height (DH). Results indicated that GH and A are the most important factors affecting the biomechanical performance of implant system, and LH, BH, MH and DH have less effect than others. The influence of custom abutment design parameters on biomechanical performance of implant system can be analyzed explicitly by the orthogonal experiment method, which offers a new method for estimating the mechanical characteristics of custom abutment.
Design and Analysis of 4LZ-8 Wheat Harvester Head
Authors: Xue Zhiyuan , Chen Xiusheng , Tang Huaizhuang , Li Mengwei
Published: December 2020

In this paper, the parameter design of the header of the 4LZ-8 wheat harvester is established, and the three-dimensional model of the header is established. The header frame is selected as the main analysis object. The force analysis and static analysis of the header frame are carried out to detect whether it meets the stiffness requirements. In order to reduce the loss caused by vibration during harvesting, the pre-stressed modal analysis is performed on the designed header on the basis of statics to obtain the natural frequency and main vibration mode of the header frame, and then the vibration frequency is analyzed. The results show that the probability of resonance of other parts of the header with the header frame is relatively low, which meets the requirements for use.
Design of Intelligent Farmland Environment Monitoring System Based on Wireless Sensor Network
Authors: Lou Xiaokang , Zhang Lixin , Zhang Xueyuan , Fan Jinjie , Hu xue , Li Chunzhi
Published: December 2020

In view of the problems of waste of water resources, high labor intensity and unscientific irrigation during farmland irrigation, and the shortcomings of ZigBee technology in the water-saving irrigation system network, such as short transmission distance, complicated network structure, and signals that are easily interfered during transmission. This paper designs a farmland environment information collection and monitoring system based on NB-IoT. The system consists of a terminal collection node, a wireless communication module and a host computer. Farmland environment monitoring system based on wireless sensor network includes wireless temperature and humidity sensor, wireless nitrogen, phosphorus and potassium sensor, Arduino MEGA development board NB-IoT communication module, gateway and Wasp mobile network, real-time collection, processing and wireless of farmland moisture data Transmission function, using NI LabVIEW software to compile the monitoring interface, real-time display of soil moisture in the form of waveform graph, and automatically control the opening and closing of the valve according to the soil moisture information. The system has flexible layout, long transmission distance, simple structure and integrated modules. It can achieve the purpose of precise irrigation and water saving, and is suitable for field planting, which has certain promotion significance.
Effect of welding sequence on residual stress and deformation of Mg alloy fillet welds
Authors: Fang Naiwen , Li Liansheng , Huang Ruisheng , Cao Hao , Xu Kaixin , Zou Jipeng
Published: December 2020

In order to investigate the effect of welding sequence on stress distribution and deformation of Mg alloy fillet welds, DE-GMAW modified Gaussian heat source model established by MSC. Marc software was applied to the numerical simulation analysis of welding temperature field and stress field and proved by measurement of residual stress by blind hole method. The results indicated that the deformation and residual stress were lowest according to the sequence of welding fillet welds from the head of cylinder to the end on one side first and then welding in the opposite on the other side. The trend of residual stress measurement results was consistent with numerical simulation analysis results with 10% error, which provided theoretical support for stress distribution and deformation control of Mg alloy fillet welds.
Design of 1SGL-240 type sugarcane deep-soiling soil preparation machine
Authors: Wei Lijiao , Li Ming , Ge Chang , Huang Weihua , Niu Zhaojun , Zhu Xianchong
Published: December 2020

Aiming at the problems of low efficiency and high energy consumption in the process of sugarcane planting, as well as the problems of soil compaction and hardening caused by tractor repeatedly entering the field and rolling sugarcane field, this paper designed a kind of combined soil preparation machine with reasonable structure and conforming to the continuous planting conditions of sugarcane field in China by optimizing the combination of key components. The tractor drives the machine into the field once, which can complete the processes of deep loosening, loosening the head of sugarcane, ridging and soil preparation. In this paper, the overall mechanism of the machine, subsoiling parts, pulling wheel, ridging mechanism and other key components are designed and analyzed, and the performance of the machine is evaluated through field test. The results showed that: the process of soil entry and subsoiling was stable, the rate of pulling out sugarcane head reached 91.2%, and all properties met the requirements of sugarcane field.
Characterization and Optimization of the Electrical Conductivity of a Semi-crystalline Conjugated Polymer PBTTT upon Doping
Authors: Wang Zifan
Published: December 2020

Semiconducting polymers have been investigated intensively in recent years due to its unique electronic properties and mechanical flexibility that could enable them to be used in a broad range of electronic applications. The electrical properties can be tuned and optimized via chemical doping which enable charge transfer between dopant molecules and organic materials. For each material, how processing conditions impact their electronic properties needs to be understood. Here, we use a representative semi-crystalline conjugated polymer poly(2,5-bis(3-teradecylthiophen-2-yl)thieno[3,2-b]thiophene)(PBTTT) to investigate how doping methods used, different dopant species and different thickness of polymers affect its electrical conductivity. We demonstrate that a combination of processing parameter could lead to the improved electrical conductivity of PBTTT thin film and point directions for future development of polymers with better electrical conductivity.
Research on Design Method of Safety Components in Grader Control System
Authors: Xue Yanjie , Hou Zhiqiang
Published: December 2020

Motor grader is one of the important equipment for modern road mechanization construction. The performance of its control system directly affects the quality after road construction. At the same time, the safety of the product is equally important as the basic attribute of the product. In order to get better product safety performance, most countries have formulated a series of standards to regulate the design process. This article introduces the design method and relevant requirements of the control system safety in the EU standards, and explains the method, model and basic process of the control system safety design using the safety components of grader control system as an example.
Dimensional Parameters Design for Flexible Cable Drive Parallel Mechanism
Authors: Liao Hongbo , Liu Kun , Zhang Xinyi , Chen Zhongkai , Yin Kun
Published: December 2020

In order to design the size parameters of flexible cable drive parallel mechanism quickly and accurately, a mathematical model of flexible cable drive parallel mechanism is established, and a design method of dimension parameters for flexible cable drive parallel mechanism is presented. By analyzing the kinematics and dynamics relation of the flexible cable drive parallel mechanism in the finite constraint space, the mathematical model of flexible cable drive parallel mechanism is derived, which includes the constraints of shape size, force and cable weight. The maximum effective working space of flexible cable drive parallel mechanism is calculated, and the dimension parameter value of flexible cable drive parallel mechanism is obtained. It provides the basis for fast and accurate design of key dimension parameters for flexible cable drive parallel mechanism.
On line monitoring method of forklift truck working condition based on multi sensor
Authors: Zhang Zhiqiang , Tian Jinjin , Zhan Peng
Published: December 2020

Aiming at the problems of poor timeliness and poor monitoring accuracy of domestic forklift working condition monitoring, a multi-sensor online monitoring method for forklift condition is proposed. Analyze the relevant factors that affect the status of the forklift truck, optimize the structure of the forklift truck condition monitoring platform, design the main control algorithm for forklift truck condition monitoring, and obtain the loading status and monitoring parameters of the forklift in the warehouse in real time. Status online monitoring. In order to verify the monitoring performance of this method, a comparative experiment is designed. The results show that the method in this paper can effectively shorten the monitoring delay and improve the detection accuracy, which is of great significance for the realization of network, intelligence and modularization of electric forklifts.
Failure and protection of metal equipment in Pumped Storage Power Station
Authors: Gao Yunpeng , Zhang Xuechao , Cheng Lu , Fang Wenxuan , Yun Feng
Published: December 2020

In order to ensure the safe and stable operation of pumped storage hydropower station equipment, it is very important to carry out regular maintenance of metal equipment. Because of the stress concentration, the stress state and the complex environment, the variable section of the turbine runner blade is easy to produce cracks, which endangers the safety of the equipment. By fully analyzing the characteristics, failure modes and causes of blade cracks, and putting forward effective detection, treatment and protection measures, cracks can be effectively prevented, which will play a key role in future equipment maintenance and repair.
Clinical mastitis detection by on-line measurements of milk yield, electrical conductivity and deep Learn
Authors: Tian Fuyang , Wang Zhonghua , Yu Sufang , Xiong Benhai , Wang Shunxi
Published: December 2020

Mastitis is the most common and costly disease in dairy cows since it can reduce milk yield, degrade milk quality, and increase healthcare costs. Detection of mastitis is an important part of udder-health management on dairy farms. Thus, the objective of this study is to develop a novel method for automatic on-line detection of clinical mastitis in an automatic milking system using the measurement of electrical parameters, data of milk production efficiency, and deep learning. The measurements were inputted into a neural network to calculate the mastitis detection index. The network was trained with 44 healthy and 6 clinical mastitic cows. 42 out of 44 healthy and 5 out of 6 mastitic cows were classified correctly after training. The trained neural network can predicted 164 out of 176 healthy quarters correctly in different evaluation data sets. These results were better than the results obtained with the model usually used on the farm.
Study of the Inherent Causes of Formation of Settlements Based on Satellite Map Observation
Authors: Zhou Yixin , Lv Tangjun , Wang Ruilan
Published: December 2020

According to legend, there are several settlements in the form of “Bagua” (also called the Eight Diagrams) in Guangdong Province of China. For a long time, the public propaganda and some scholars all consider that the construction of this type of settlement is an imitation of gossip, so-called Bagua of Tai Chi. Using satellite map observation technology, this study defined the preliminary concept of the settlements in the form of Bagua, collected the statistics of the quan-tity and location of these settlements, and gathered a description of the distribution and overall plane graph of them. Through graphic analysis and isomorphism method, it is found that iso-morphic relation exists in many ways between the distribution region of those settlements and their surrounding geographical environment.

From our viewpoint, the form of Bagua is only the external appearance of the settlements, and there are more important inherent causes of formation for them. First of all it is the defense of floods, followed by the defense of human disasters, and last but not least it is the adaption to the forms of social organization. The formation of the settlements in the form of Bagua had an ap-parent cause of defending the natural and human disasters, and it adapted the forms of social or-ganization. Then in the development of these settlements, the influences of the Bagua of Tai Chi as well as feng shui are integrated. In nature, the purpose of settlement form is to create optimal living environment.
The Road Spectrum of Combine Harvester Based on Virtual Iteration
Authors: Ming Dong Ming , Feng Lin Shu , Yao Wang Meng , Guang Hu Yao
Published: December 2020

The combine harvester has a complex work environment, and the reliability of the rack is critical to the functionality of the machine. In order to shorten the test time, reduce the cost of research and development, and make the road spectrum can be reproduced on the test-bed, this paper takes the combine harvester as the research object, the acceleration spectrum was measured on asphalt road, hard road in field and wheat field, and the multi-body dynamic equation was established according to the actual parameters of the vehicle. The transfer function between the tire displacement signal and the target signal is established, and the tire displacement spectrum is calculated. The road spectrum is taken as the input load of the four-column test-bed, and the actual load condition is reproduced on the test-bed, which provides the input condition for the fatigue analysis of the combine harvester rack in the later stage, and greatly enhances the efficiency of durability design.
Influence of the failure effect of MEMS capacitive high g acceleration sensor on the limit range and sensitivity
Authors: Liu Yong , Li Changsheng , He Guanhua
Published: December 2020

With the development of MEMS capacitive accelera-tion sensor to a higher measurement range (tens of thousands of g or even hundreds of thousands of g), the failure of the device microstructure under extreme mechanical impact has become a key factor restricting its performance improvement. Existing research mainly focuses on material stress failure and device structure optimization. Aiming at the failure of micro structure under impact, a simulation model of impact response of micro structure is established in this paper. Based on the existing over stress failure and device structure optimization, the stress failure effect and short-circuit failure effect of MEMS capacitive acceleration sensor under strong impact are proposed, and the influence rules of the two failure mechanisms on the sensor limit range and sensitivity are obtained. At the same time, the optimization design of the key structural parameters of the sensor is discussed.
Research on the Main Charge’ Stability of Certain Electric Firing Cluster Tear Bomb
Authors: Cui Xiaoping
Published: December 2020

In order to study the main charge’ stability of certain electric firing cluster tear bomb, the sampling research was carried out from the storage period, the storage period and the over storage period of the ammunition. The dispersion and stability of the samples main charge’ components were characterized and tested in different years by SEM, DSC and other methods. The SEM diagrams of the main charge show that the components are still distributed evenly after long-term storage, and there is no obvious change in quality. The DSC results show that the stability of main charge is excellent, this is due to that the displacements of the melting endothermic peak and decomposition exothermic peak between unstored and stored main charge are less than 2 °C.
SMA-based simulation data demand acquisition in the field of mechanical equipment
Authors: Jingwei Wang , Ping Gu , Siyu Li , Jian He
Published: December 2020

In view of the complexity of the simulation system in the field of mechanical equipment and the difficulty in obtaining the simulation data, the idea of requirement engineering is adopted. After comparing the current common demand analysis methods, the comprehensive micro analysis method is introduced to analyze the data demand. In this paper, the application process model of the comprehensive micro analysis method is also constructed to describe the application process of the method.
Research and Application of Locking Strip for Inter-Hexagon Screw in Main Pump for Nuclear Power Station
Authors: Wang Zheying , Zhong Shan , Cao Yu , Cheng Hanchi , Sun Qi , Fu Wei , Lin Bin , Tan Junzhe , Tao Shaojia , Liu Peng , Li Jing
Published: December 2020

The loosening of inter- hexagonal screws connecting internal parts in main pump for nuclear power station causes some nuclear safety problem due to medium erosion at present. Aim at the problem, a special locking strip for inter- hexagonal screws is put forward and the structure of the locking strip, the bending process and the forming die of the locking strip are designed and calculated in this paper. Furthermore, the fastening tool of the locking strip is designed, and the feasibility of the locking strip is verified in the experiment so as to improve the anti-loosening reliability. The locking strip for inter- hexagonal bolts can be widely applied to the locking and fastening industry application fields.
System Transfer Function of Incoherent Light Illumination System
Authors: Sun Yueling
Published: December 2020

Generally, most imaging cases are incoherent light field illumination, and incoherent light illumination system has the advantages of simple installation and no coherent noise, therefore it has received extensive attention. The optical transfer function of illumination system is an effective method to evaluate the imaging quality of such optical system. In order to evaluate the imaging quality of an optical system, the specific form of the system transfer function should be known. However, due to the in-coherent nature of the optical field, both the input function and the impulse response can only be non-negative real functions, it is difficult to deal with lots of bipolar inputs and impulse responses. In this paper, two methods for calculating the system transfer function of incoherent light illumination system under quasi-monochromatic light illumination are given. Method 1: the coherence of incoherent light is defined, and the coherent system transfer function based on the characteristics of the system transfer itself is deduced. Method 2: based on the theory of partially coherent light, started from Kirchoff’s diffraction integral, the quasi-wavefront aberration is introduced, and the spatial coherence of the light field is described by the mutual intensity instead of the mutual coherent function, finally the system transfer function of incoherent illumination is derived. The calculation formula is simple and the transfer function of incoherent light system can be calculated accurately and easily. The work in this paper is helpful to the study of the new phenomena related to incoherent optical imaging.
Irrigation remote control system based on LoRa intelligence
Authors: Xue Yuan Zhang , Kang Lou Xiao , Xin Zhang Li , Chao Shan Yong
Published: December 2020

In order to realize automatic remote monitoring and intelligent management of intelligent irrigation system, aiming at the existing problems of water-saving irrigation system, an intelligent irrigation system based on wireless remote control was designed by using LoRa wireless communication technology to realize low power consumption and low loss monitoring technology. This paper introduces the way and system architecture of ad hoc network in detail, and the establishment of irrigation mathematical model and irrigation algorithm in different periods of cotton field, which not only improves the utilization rate of water resources, but also realizes the intelligence of irrigation system, and promotes the transformation from traditional agriculture to intelligent agriculture.
Design Of An Automobile Exhaust Heat Energy Recovery Device Based On Linear Generator
Authors: Dai Haocheng
Published: December 2020

The device collects the heat energy in the exhaust gas of the car, and realizes the recovery and utilization of the heat energy according to the unique heat energy collection device and the highly efficient linear opposed generator. Through the experiment, it is obtained that the exhaust temperature of the fuel car after doing work can reach about 600-800°C, and if it is a turbocharged engine, the exhaust temperature can reach more than 900°C. Investigations and studies have shown that only 20% to 45% of the energy released by automobile fuel combustion is effectively used, and the rest is dissipated as heat. Among them, the energy carried by engine exhaust accounts for 50%-60% of the total dissipated energy. Therefore, we recover the exhaust gas of the car and convert the low-quality thermal energy into high-quality directly usable electrical energy and use it reasonably. In this work, a set of automobile exhaust heat energy recovery device is designed to modify the automobile exhaust pipe part. In the scheme, the exhaust pipe manifold is converted into a spiral structure, and the opposite linear generator is designed. We use the spiral structure to heat the high-temperature thermal energy in the exhaust gas, heat the internal water to high-temperature, high-pressure saturated steam, and then send it to the opposite linear generator cylinder. Our design makes use of the exhaust sequence of the engine, opposites each other, and works back and forth to achieve the purpose of energy recovery [1]. In this scheme, only the exhaust manifold needs to be modified, and no other consumables other than water are needed during operation. The recovered energy can be used for automobile driving and storage. At the same time, the absorption of high-temperature exhaust gas will also reduce the emission of nitrogen oxides. Through this scheme, energy recovery and the elimination of harmful gases can be achieved at the same time, and the purpose of energy saving and emission reduction can be achieved [2].
Failure analysis of a steam-water boiler
Authors: Ren Facai , Hou Shaoyi , Si Jun
Published: December 2020

The explosion failure reason of a steam-water boiler was analyzed through macro analysis and theoretical calculation. The results show that the overpressure operation of the boiler is the main cause of the explosion accident.
Study on the microstructure and heat affected zone of nickel-based alloy cladding layer
Authors: Luo Yunqiu , Liu Zongde
Published: December 2020

Six Ni-Cr-Mo cladding layers were prepared on the surface of Q235 steel by laser cladding technology. SEM and EDS were used to detect the crystal structure and element diffusion trend of the cladding layer, and the microhardness of the cladding layer and the substrate was tested with a micro hardness tester. The structure of the heat affected zone (HAZ) obtained by different preparation processes was analyzed. The experimental results indicated that the hardness of the cladding layer was about 1.5 times that of the substrate, which improved the wear resistance of the material. SEM / EDS results illustrated that the cladding layer and the substrate showed a good metallurgical bond, and the microstructure on the cross-section of the cladding layer from the junction to the surface gradually transitioned from cell crystals to dendrites. The element diffusion curves showed that the diffusion amount of Fe element is the largest and that of Mo element is the smallest. The morphology of the heat affected zone is very different from the substrate and the cladding layer, there are only pearlite and ferrite in the substrate, while martensite appears in the heat affected zone.
Quantitative Hg Content Migration Process I. YangDongfang Migration Model Calculation
Authors: Yang Dongfang , Wang Qi , Lin Dong , Zhang Longlei , Li Haixia
Published: December 2020

Based on the investigation data of Jiaozhou Bay in May, August and October, 1992, the migration process of Hg content that came from atmospheric subsidence in Jiaozhou Bay was studied. In August, the central point 2016 in the east of Jiaozhou Bay was taken as the source of atmospheric subsidence, with the Hg content of 0.050 μg/L. A series of concentric circles with different gradients have been formed with station 2016 as the center. The Hg content decreased from 0.050 μg/L in the center to 0.021 μg/L in the center of the Bay, 0.037 μg/L in the northwest, 0.031μg/L in the northeast and 0.033 μg/L in the southeast of the bay. According to the absolutely horizontal loss rate model of matter content, it was calculated that in August, in the eastern part of Jiaozhou Bay, from the eastern central water area to the central water area of the Bay, the absolutely horizontal loss rate of Hg content in the surface was 0.40 Yang Dongfang absolute number, 0.19 Yang Dongfang absolute number in the northwest water area of the bay, 0.45 Yang Dongfang absolute number in the northeast water area of the bay, 0.63 Yang Dongfang absolute number in the southeast water area of the Bay. According to the relatively horizontal loss rate model of matter content, it was calculated that in August, in the eastern part of Jiaozhou Bay, from the eastern central water area to the central water area of the Bay, the relatively horizontal loss rate of Hg content in the surface was 8.00 Yang Dongfang relative number, 3.80 Yang Dongfang relative number in the northwest water area of the Bay, 9.00 Yang Dongfang relative number in the northeast water area of the Bay, 12.60 Yang Dongfang relative number in the southeast water area of the bay.
A novel Laser Doppler Velocimeter based on a liquid lens
Authors: Chongbin Xi , Zhou Jian , Nie Xiaoming , Huang Rong
Published: December 2020

This paper proposed a novel Laser Doppler Velocimeter (LDV) based on an electrically tunable lens (ETL) to change the working distance and to extend the measuring range of LDV. On the basis of Gaussian optics, the positions along with the size of waist spot are simulated under different driving current of ETL. In addition, the working distance and measuring range of LDV under different offset lenses were measured. The results demonstrate that the LDV based on ETL is able to change the working distance and effectively enlarge the measuring range of LDV, whose volume is reduced simultaneously.
Compression constitutive relationship of RPC with different steel fiber content
Authors: Yu Xinmin , Fu Benzhao , Chen Shichuan
Published: December 2020

Uniaxial compression tests were carried out on RPC with different steel fiber contents. The mechanical properties of RPC and the compressive-stress-strain curves of RPC with different steel fiber contents were studied. The results show that under the same mixture proportions, compressive strength increase with the increase of steel fiber content. When the steel fiber content is 3.5%, the compressive strength of RPC cubes is the largest; under the same mixture proportions, the compressive strength of RPC cube is approximately linear with the compression strength of prism, and the peak compressive strain and elastic modulus ratio of RPC cubes increase with the increase of steel fiber content. In this paper, the equation of the rising and descending sections of the stress-strain curves of different steel fiber volume admixtures is derived. According to the results of this test, the relationship between rising section, descending section coefficient and steel fiber content is obtained.)
Summarize the Corrosion and Protection of Drum-Shaped Filter in Nuclear Power Plant
Authors: Zhang Huihui , Liu Zongde
Published: December 2020

The drum-shaped filter of the pressurized water reactor nuclear power plant is prone to corrosion due to the influence of sea water, moist air and other factors all year round, which puts a burden on the economic and safe operation of nuclear power plants. In this paper, the corrosion forms and causes of different parts of the drum-shaped filter are analyzed and expounded, and protective measures are put forward.
Research on the Cushioning Effect of Protective Materials under High Impact
Authors: Chen Runfeng , Sui Li , Liu Qiang , Qiu Qiangqiang
Published: December 2020

Aiming at the protection of the internal components of the projectile during penetration, the cushion performance of common protective materials such as polyurethane, felt, polytetrafluoroethylene (PTFE), and copper were tested. The test results show that the copper and felt have a certain cushioning effect, which can reduce the acceleration amplitude of 23,000 g by 18% and extend the pulse width of acceleration overload. The cushioning effect of PTFE material is not obvious, but it can play a role in mechanical filtering, making the acceleration curve smoother. Polyurethane material will increase the acceleration amplitude of the buffered part, it is not suitable as a buffer material.
Research on the Measurement of the Gravity Center for the Workpiece with Complex Curved Surface
Authors: Yuan Xu , Chao Zhang , Cheng Qian , Shijie Su
Published: December 2020

Taking the 300 kg-class single blade of the controllable pitch propeller as the research object, based on the principle of three-point gravity measurement, a secondary weighing method is developed, which obtained the relative coordinate value of the gravity center by making a difference between the two weighing data. According to the concept that each axis is independent, an error model of spatial attitude is established. The attitude deviation is obtained by using sensor scanning, and the actual coordinate value of the blade gravity center is obtained by combining with the space attitude transformation matrix. The experimental results indicated that the secondary weighing method with the space attitude transformation matrix in this paper was useful and highly accurate. The method has certain guiding significance for the gravity center measurement for workpieces with large and complex curved surface.
Research on composite material in RMS control of antenna
Authors: LI Yu-Hua , Jing Li-Li , Jian Jiang Wen , Wen Shi Jin
Published: December 2020

In this paper, the main factors of the deformation of composite satellite antenna reflector are analyzed, and the related basic research work is carried out from two aspects of tooling material selection, structural design and product main material selection. The conclusion can be used to guide the follow-up work, and also provide ideas and basis for high-precision antenna.