DEStech Transactions on Materials Science and Engineering
Cavitation Erosion Behaviour of Martensitic Stainless Steels SUS 420J2 and SUS440C by High Pressure Liquid Jet
The high-pressure cavitation erosion (CE) behavior of SUS420J2 and SUS440C were studied by a high pressure cavitating liquid jet experiment apparatus, according to ASTM Standard G134-95. The microstructures were investigated by X-ray diffraction and scanning electron microscopy to determine the phases and precipitates. The mass loss vs. exposure time relations indicated that SUS440C had longer incubation time and a decreasing erosion rate. The eroded topographical evolution was investigated, indicating that the initiation of cavitation erosion was accumulated from grain boundaries for SUS420J2, and from M3C precipitates or ferric oxide inclusions for SUS440C. The dominant factors that influenced CE behaviors changed in different cavitation stages. Micro-pitting and initial damage induced by grain boundaries or precipitates were the dominant erosion forms during the incubation stage; however, the matrix hardness started to prevail as the dominant factor after the precipitates had been torn off, or grain boundaries damage disappeared.
Improvement of Virtual Simulation by Means of Sewing Patterns
The aim of this study is to improve the virtual garment simulation in terms of fit prediction and new body measurements application. In our study, fit criteria of the back pattern blocks was established. The important body measurements of neck, shoulder and armhole area were measured on cross-section to evaluate the pattern block. New method of sewing patterns evaluation can be used to check the correctness of blouse pattern block effectively and improve the virtual technology.
Design, Simulation and Experimental Verification of Chip-Level Cracking Structure
To quickly destroy chip and ensure information security, the author designed a cracking structure of transient-failure integrated circuit in this paper. By placing the Ni-Cr film resistance and the energetic material between the chip and the package and heating the resistance by an electric current, the energetic material expanded and the chip cracked. The information on the chip was destroyed, destroying the information on the chip. The author simulated the temperature distribution and stress of the power-on structure in different sizes by ANSYS software. The simulation results indicate that, the chip cracks within 50ms under the trigger current of 0.5A when a circular groove with an area of 1mm2 and depth of 0.1mm is filled with an expansion material with an expansion coefficient of 10- 5·℃-1. Then the author prepared a sample for experimental verification. Experimental results show that the sample chip quickly cracks and fails within 10ms under the trigger current of 1A. The simulation and experimental results confirm the feasibility of the structure in quick destruction, which lays the foundation for developing instantaneous-failure integrated circuit products to meet information security applications.
Computer Technologies for Designing Close- Fitting Apparel with Specific Properties
In this study, based on the 3D scanning technology and virtual simulation, the digital twins of female bodies were adjusted and developed, and a virtual simulation of wetsuit was carried out. The virtual wetsuit was evaluated through the digital twin morphology, and the wetsuit sewing pattern block was optimized through composite material strain and compression value. The experimental tests show that the digital twins of system "body - wetsuit" based on real data transformation are feasible and practical, and the optimized pattern block guarantees good fit performance.
Automatic Evaluation of Sleeve Pattern for Classical Women Jacket
Good fitting sleeve is an important criteria of clothing quality, on the one side, the process of sleeve assembling is very complex and time consuming on the other side, the purpose of this study is established the database of pattern block parameters and the algorithm of fit evaluation by means of special criteria through virtual try-on and subjective assessment, which allow to predict wearing effect before sewing. In order to make results obtained convenient, automatically evaluation of torso and sleeve pattern blocks is implemented by Python. Therefore, this study can help to develop CAD of classical women jackets in terms of designing and production.
Evaluation of Fit Criterias by Means of Eye-Tracking Technology
In order to analyze the degree of people's attention to different clothing parts under the condition of clothing fit evaluation, this paper takes different fit criteria of women blouse as the research object. In this research, subjective questionnaire evaluation experiment and eye tracking experiment were conducted respectively. By analyzing the subjective evaluation results, participants have the ability to correctly evaluate the comfort of clothing and further conduct eye-tracking experimental research. Moreover, eye -tracking indexes data such as fixation duration and fixation counts of 20 areas of interest of 15 blouses with different fit degree were obtained through eye-tracking experiment. Then the mean values of eye-tracking data of different fit degree and areas of interest were compared and multivariate analysis of variance was conducted. And the heat map which can present the duration of fixation in the areas of interest was analyzed. The results showed that the total duration of fixation and the fixation counts of participants in different areas of interest were significantly different. and the degree of attention paid to the clothing parts of the women blouse was the bust, shoulder, waist and sleeve when evaluating clothing comfort with different fit criteria. This paper has scientific reference significance for improving the method of pattern making and women blouse comfort.
A High Speed and Wide Frequency Division Range Mixed-Signal Pulse Swallow Frequency Divider for Phase-Locked-Loop
A frequency divider for a high speed and wide band Phase- Locked-Loop (PLL) which output frequency range is from 6 GHz to 12.5 GHz, is described. The designed mixed-signal swallow pulse divider mainly includes a divide-by-8/9 dual-modulus prescaler which is based on source coupled logic (SCL) structure for achieving high speed frequency division, and a 3-bit swallow counter and an 8-bit programmable counter to achieve wide range division ratio. This divider is fabricated in 65nm CMOS process and the power supply voltage is 1.25 V. The simulation results show that the power consumption of this divider is 5.34 mW. And the divider can achieve a continuous integer division ratio from 72 to 2047 in the PLL tuning range.
Dynamic Simulation and Analysis of the Synchronous Mechanism of High-Speed Machine Tool Protective Cover with Joint Clearance
The synchronous mechanism is the driving part of the machine tool guide rail protection device, which makes the relative speed of each cover sheet the same, which can well reduce the vibration and noise generated by the machine tool protection device. In high-speed operation, because the gap in the hinge pair of the synchronous mechanism has a great influence on its movement accuracy, this paper establishes a multibody dynamics model of the synchronous mechanism of the high-speed machine tool guide rail guard based on the Hertz theory, and uses ADAMS to The dynamic simulation analysis of the synchronous mechanism of the clearance shows that the pin near the joint between the worktable and the cover has the greatest influence on the motion accuracy of the synchronous mechanism. At the same time, the speed of the pin is analysed under different clearances. The transformation law of acceleration, contact and collision force of the kinematic pair with clearance and its influence on the performance of high-speed machine tool guards.
The Secondary Lubrication Effect under Fluid Lubrication
Surface texturing under fluid lubrication has been effectively used to improve the tribological performance. However research on the ‘secondary lubrication effect’ in the later stage of fluid lubrication is scarce. This study aimed to examine the friction reduction mechanism of the ‘secondary lubrication effect’ under fluid lubrication and to investigate factors that affect the effect. Lubrication models were developed under fluid lubrication. Friction force and hydrodynamic pressure of the lubricant were analyzed. Furthermore, the texture's oil-storage and -release capacities which may affect the ‘secondary lubrication effect’ were studied respectively. The results showed that the ‘secondary lubrication effect’ reduced friction by generating hydrodynamic pressure. The friction force in the later stage was higher than that in the early stage of fluid lubrication. The decrease in friction caused by the ‘secondary lubrication effect’ decreases in proportion with the loss of the lubricant. The lubricant infiltration capacity will affect the ‘secondary lubrication effect’ by influencing the texture's oil-storage capacity. Additionally, the release mechanism of the lubricant inside the texture was also obtained. Texture depth had a significant effect on the‘secondary lubrication effect’ by affecting the texture's oil-release capacity.
Effect of Texture Shape on Texture’s Frictional Response
A reasonably designed surface texture can effectively control the frictional properties of the textured substrate. The texture shape has an important influence on the frictional properties of the textured substrate. The ABAQUS software based on the CEL algorithm was used to compare the friction reduction mechanism of the square groove-like texture and the V-shaped groove-like texture, and the uniformity of the texture shape on the frictional properties of the texture was obtained. The simulation results show that the shape of the texture affects the frictional properties of the textured substrate under lubricating conditions by affecting the stress concentration phenomenon generated on the surface of the textured substrate and the hydrodynamic lubrication effect of the texture. This has certain reference significance for the design and selection of texture shapes and the improvement of the accuracy of lubrication models.
Analysis and Optimal Design of Antenna System's Forced Performance
The application of antenna system is becoming more and more widely. With the increasing demand for active phased array radar antenna, a kind of antenna array and antenna structure system for active phased array radar antenna is designed. According to the engineering requirements, the structural scheme is specifically designed, and the static analysis under static load and dynamic under random load are carried out by using finite element analysis software The mechanical analysis verifies the excellent mechanical properties of the structure scheme, the accuracy of engineering accuracy and the excellent ability to bear random load. This paper puts forward a kind of platform optimization scheme which applies prestress to antenna platform, and proves the rationality of the scheme through calculation.
Comparative Study on the Influence of U-Shaped Self-Organizing Production Line Configuration on Capacity
There are three typical representatives of U-shaped selforganizing production line, namely U-shaped Travelling, Chasing- Overtaking, Cellular Bucket Brigade. The equipment, placed according to the process sequence, and the distance between the equipment form a Ushaped production line configuration. The former forms the process imbalance variable, and the latter forms the aisle width variable. For this, a simulation experiment with process imbalance and aisle width as independent variables and production line capacity as dependent variable was designed. The Plant-Simulation® simulation platform was used to obtain experimental data and verify it. The results show that Chasing- Overtaking capacity is the highest under the same conditions. The production capacity of Cellular Bucket Brigade line and U-shaped traveling line is lower than that of CO line by more than 20%; and under the discrete system, the three self-organized production lines are not affected by configuration factors.
Study on the Simulation and Variation Law of Particle Erosion Velocity of Flow Field in Recoil Mechanism
During the recoil and recoil motion of the gun, the solid particles in the recoil mechanism will repeatedly impact the control ring, resulting in erosion and wear phenomenon, which has become the main cause of the failure of the control ring. By means of fluent software, a two-phase flow model based on liquid-solid coupling is established, and the motion trajectory and erosion velocity of solid particles are calculated by numerical simulation, and the influence of different parameters on particle erosion velocity is studied, which provides reference data for the simulation of controlled ring erosion and the study of wear law.
Research on Integrated Management of Multi-Source Heterogeneous Disaster Data
An earthquake is a natural disaster with great destructive power and serious harm to humans. The collection of earthquake disaster information is a very complicated task, and it is even more difficult to mine valuable information from the massive, scattered and real-time changing disaster data. In response to the problems of slow and fragmented postearthquake disaster acquisition, large errors in disaster assessment, and inadequate decision support, this paper describes the design of open data interfaces to collect disaster data information from different sources and different structures in the shortest time, then implement integrated encoding to achieve dynamic management of disaster data throughout the life cycle. The experiment shows that the effect is good. This result provides a decision-making basis for rapid and effective emergency rescue of relevant departments.
Indirect Measurement of the Cutting Power Based on Spindle Motor Current
Enhancing energy efficiency of machine tools can significantly improve the environmental performance of machining systems, and acquisition of cutting power is the key to solve this problem. However, the approach that the cutting power is directly measured by the dynamometer can’t be utilized in real life application. In this paper, a cutting power estimation model, based on the inexpensive and non-invasive spindle motor total current and spindle idle current measurement, is proposed for the intermittent cylindrical turning operation. Novel signal processing strategies have been proposed for extracting useful features from the measured signals. Some experiments are performed on a CNC lathe HCK60 for the identification of the load meter constant and the analysis of the estimate error. As a result, it shows the effectiveness of the proposed method for estimation of cutting power, which can enhance the overall productivity of the machining process by optimally selected cutting parameters from the predicted model.
Cracks Forming and Propagation Mechanism for the Q345 Steel during Cooling
Cracks always occur for the Q345 steel during cooling, which usually lead to Welding failure. Through investigation of the cracks forming position and propagation path, its forming and propagation mechanism for the melted Q345 steel during cooling was studied in detail by using of SEM, EBSD and Nano Indenter equipment in this paper. SEM observation results imply that cracks mainly initiated at martensite phase region close to basal material. Moreover, it also can be observed that the cracks always propagated along the martensite lath or packets boundaries, but not the original prior austenite grain boundaries. The hardness differences between cracks adjacent positions and matrix is about 2.48 GPa, which is larger than that of melted region and matensite (0.70GPa). In addition, EBSD results show that the average prior austenite grains boundaries angles (30-50º) are always smaller than that of martensite lath and packet boundaries (>50º). Combining investigation of the cracks forming position, propagation path and microstructure misorientation, it proves that the occurrence of the cracks at junction of martensite phase region close to basal material is related with larger hardness difference or larger residual stress between martensite and ferrite, while cracks propagation path is controlled by the boundaries angles or local misorientation. The cracks incline to propagate along or deflect to large martensite lath and packets boundaries.
Parameterization Historical Women’s Sleeves
Nowadays, the garments with historical elements often are appearing in fashion shows and real life, and the historical-oriented style becomes very popular. The point of contemporary interest is historical sleeve shape. Between the 15th and 18th centuries, there were three different stages of costume design: Renaissance, Baroque and Rococo during which the sleeves of women's wear were varied. Historical sleeves are influencing the subsequent fashion design and indispensable excellent resource of inspiration. In this research the contours of women's sleeves were explored. This paper selects the famous brands Valentino and Chalayan, and analysis of an application of historical women's sleeve elements in the design. It provides a theoretical basis for the application of historical sleeve elements in contemporary women's wear, and a practical application in virtual reconstruction.
Radar Emitter Identification Based on Stacked Long and Short Term Memory
With the increasing complexity of electromagnetic environment and the rising of operating patterns of new radars, emitter identification is becoming more and more difficult. This paper presents a radar emitter identification method based on stacked long and short term memory (SLSTM). Radar pulse train can be directly used as input without extracting other features, which greatly simplifies the data preprocessing and realizes the "end-to-end" recognition of radar emitter signal. The timing characteristics of the pulses are automatically extracted by SLSTM, and the optimal network parameters are trained to complete radar signal identification. Compared experiments with conventional methods are conducted, and the results show that the proposed model outperforms other existing techniques. Moreover, simulation experiments in different noise and loss pulse environment show that the method is effective and robust in solving problems of radar emitter recognition.
Algorithm of Contour Contour Contour of Complex Surface in NC Machining
A residual height trajectory algorithm of complex surface plane envelope is proposed for NC grinding of complex surface. Firstly, based on the differential geometric relationship between the grinding wheel end plane and the workpiece surface, the properties of the plane enveloping surface are analyzed; secondly, the residual height based on the space vector is calculated; Secondly, the algorithm is proposed by using the tangent characteristics of the contour line of the equal residual height; Finally, the tool path of the ellipsoid convex surface is calculated, and the characteristics of the two different tool paths are compared and analyzed, and it is proved that the proposed method is effective The tool path has higher machining efficiency at the residual height.
An Ontology Based Methodology for Capability Requirements Analysis and Verification of the Military Information System
To solve the problem of capability requirements analysis and verification of the military information system, a new method based on ontology is proposed in this paper. Firstly, meta ontology of capability requirements is designed based on its analysis process. And then meta ontology is instantiated to construct the capability requirements model according to the scenario of specific applications. Secondly, the data completeness and data consistency rules of the model are extracted from the ontology directly according to the relations among the data entities of the ontology, and the data entities are used to develop the verification matrixes, which are utilized to judge the data completeness and data consistency of requirements model. Finally, a typical example is given to illustrate the implementation process of our method, and the results demonstrate its feasibility and validity.
Research on Integrated Quality Control in Product Manufacturing Stage
In view of the weak quality control in manufacturing process, the lack of data support in decision planning layer and management control layer, this paper analyzes the operation flow and quality data link of datadriven product manufacturing quality integrated control business operation process and quality data link, studies the multi-process manufacturing process quality integrated control method, realizes the machining error and quality dynamic control between multi-process in complex parts manufacturing process, improves the machining precision and efficiency of parts, puts forward the dynamic control method of machining process quality for component assembly, establishes the relationship between complex process capability index and matching degree, and realizes the prediction analysis and optimal matching of assembly results, effectively improve the assembly quality and assembly efficiency of precision components.
Study of DLC Formation with Ion-Beam Assisted Magnetron Sputtering Deposition
TiC-containing DLC films are deposited by magnetron sputtering by means of ion beam deposition using acetylene as carbon source. The deposition rate of the films is three times as fast as that by ion beam deposition alone. The minimum roughness is 2.2 nm and the highest hardness is 11.97 GPa for the synthesized DLC films. The effects of ion beam voltage and deposition temperature on the composition, microstructures, and surface states are studied using infrared spectroscopy, XRD, Raman spectroscopy, and AFM. Mechanical properties of the DLC films from nanoindentation tests are analyzed with the variation of H and TiC, as well as content of sp3 bonds.
Study on Weldability of Aluminium Alloy TL091 in Resistance Spot Welding with Intermediate Frequency and Direct Current
The resistance spot welding with intermediate frequency and direct current (RSWIFDC) was conducted to solve the weldability of the Al alloy TL091, The high-quality joint bearing dynamic load is realized for the first time by using the technique with the power of 2 kHz and the double-transformer based on the rapid response speed and stable welding current. By optimizing the welding process parameters, the strength, hardness distribution, microstructures and fracture morphologies of the joints were analyzed in details. The experimental results showed that the joints welded by the technique had better comprehensive mechanical properties, higher tensile strength and plasticity than that of the joints obtained by other spot welding. Shear fracture of the joints was seen at the nugget instead of the HAZ, thus indicating that the strength at the HAZ is higher than that at the nugget. The plastic ring of the joint was narrower as we desired. It was concluded that, by developing this advanced welding method and optimized welding parameters, high-quality joints were acquired to meet with higher design requirements of body-in-white of Al alloy under dynamic load. This is of great significance to the wide application of Al alloy body.
The Design and Optimization of Swing Automatic Paper Folding Mechanism
In order to solve the multi-directional bending problem of paper cards with different specifications, a swing type automatic paper folding mechanism was designed. Through gear rack mechanism and rocker slider mechanism, the paper card can be folded vertically and horizontally for many times. The MATLAB optimization function library is used to optimize the rocker, connecting rod, swing angle and other size parameters of the mechanism, and the swing angle of the bending block is determined to be 15 degrees. The motion equation of paper folding process is solved by vector equation and coordinate transformation, and kinematics simulation of swing paper folding mechanism is carried out by motion plug-in of SolidWorks. The simulation results show that the mechanism can meet the motion requirements of the waist seal, and the simulation parameters are consistent with the calculation parameters.
Research and Simulation on Principle of Walking Driving Mechanism for In-Pipe Worming Robot
Aiming at the problem of large drag force of robot in narrow pipe space, a new type walking driving mechanism of in-pipe worming robot was proposed in this paper. The main force-exerting driving is an incomplete gear-rack mechanism, it has the characteristics of high transmission efficiency and good manufacturability. The walking principle and walking step-speed and drag force had been analyzed. When virtual prototype established the simulation experiments analysis were completed, the numerical results are in good agreement with the theoretical analysis, to a certain extent, the rationality and feasibility of the new type walking driving mechanism proposed of in-pipe worming robot had been verified, these provide the basis foundation for the manufacture of physical prototype.
Design of Polyphase Channelization Algorithm Based on CUDA Stream Architecture
In order to improve the reconfigurability and computing efficiency of the polyphase channelization system, a new algorithm based on CUDA stream architecture was designed and optimized. Firstly, the principle of parallel channelization algorithm without blind zones is introduced. Then, various resource constraints under CUDA architecture and the relationship between the operating efficiency and parameters of the CUDA kernel under these constraints are analysed. The implementation structure of polyphase channelization algorithm is designed. Finally, NVIDIA GPU is used to implement and test the polyphase channelization algorithm based on CUDA stream. The result proves that the computational efficiency of the structure designed in this paper meets the real-time requirements, and can get about 10% efficiency improvement compared with the traditional algorithm.
Implementation of VLBI Digital Baseband Converter with CUDA
In order to upgrade the VLBI digital baseband converter of China's Deep Space Network (CDSN), a CUDA-based design method for polyphase channelized VLBI digital baseband equipment is proposed. Firstly, the parallelism of each module of the baseband conversion algorithm is analysed. Then the overall implementation structure of the polyphase channelization algorithm and the kernel of each module are implemented based on CUDA Stream. Finally, the indexes of the system are tested by simulation experiments. The results show that the system designed in this paper is flexible, simple and efficient, and can meet the requirements of CDSN VLBI system.
Analysis of the Effect of Sio2 Film on the Characteristics of Rayleigh Wave in Zno/Sic Structure
The influence of SiO2 film on the phase velocity and the electromechanical coupling coefficient of ZnO/SiC structure was analyzed by finite element method. The results show that the middle SiO2 film layer reduces the phase velocity of Rayleigh wave and significantly increases the electromechanical coupling coefficient. When the top SiO2 film layer thickness is larger than the ZnO film thickness, the Rayleigh wave phase velocity increases. Otherwise, the Rayleigh wave phase velocity decreases. The electromechanical coupling coefficient increases first and then decreases. These conclusions can guide the development of surface acoustic wave devices with high phase velocity and high electromechanical coupling coefficient.
Simulation and Analysis of the Posture of Walking Board of "One-Pull-Four" Tension Stringing in Small Span Length
With respect of the gap in current "one-pull-four" tension stringing simulation calculation, a "one-pull-four" tension stringing numerical simulation model is established relying on the Ya'an II~Ziyang 500kV line project, based on ADAMS software, and the posture of walking board is discussed to obtain the influence relationship between the central deflection coefficient of the conductor and the posture of the two in this paper. In the range of small span length, the method of selecting the value of central deflection coefficient suitable for conductor steering is determined through simulation analysis of steering, which provides a basis for the actual construction of power transmission and transformation lines.
Performance Analysis of Passive Radar System Based On GPS Signal
Passive radar systems based on navigation satellite reflected signal achieve the target detection and location by receiving and processing Globe Navigation Satellite System (GNSS) reflected signal efficiently. This paper puts emphasis on study of characteristics of the navigation reflected signal. The GPS signal coverage, C/A code ambiguity function, the amplitude and phase of the reflected signal GPS, polarization characteristics of the reflected GPS signal have been studied. Simulation of the system detection performance based on airborne receiving system has been performed. The simulation results show that the signal processing gain for the passive radar system based on GPS reflected signal is quite high. The currently conventional GPS receiver could not detect the low level signal, new signal processing techniques or high-gain antenna and other ways should be used to make up for the high demand of signal processing gain.
Mechanical Properties and Failure Analysis of Lattice Grid Sandwich Structure
In this study, quare, kagome and triangular grid sandwich structures about carbon fibre reinforced epoxy (CF/EP) composite, were designed and manufactured. Mechanical properties of these designed sandwich structures were performed by three-point bending and finite element analysis (FEA). The bending stiffness and core shear stress were calculated and then compared. Results obtained indicate that stress concentration was found at loading regions that cracks occurred on the interface. The face yielding and core shear failure also play a key role in the sandwich grid structure. The results show that the carbon fibre fabricated triangular grid core has a much stiffer and stronger character than other structures.
Numerical Simulation and Experimental Investigation of Friction Stir Rivet Welding Process for AA6061-T6
This article proposed a novel friction stir rivet welding process to join aluminum alloy 6061-T6 sheets in lap configuration with threaded rivet employed. The material flow behavior and temperature distribution of FSRW process are analysed using Simufact Forming 15.0 software, and joints have been obtained on the modified CNC machine with 1200rpm rotational speed and 10s dwell time. Rotational speed and dwell time are important factors which affecting mechanical properties of FSRWed joints. The welding heat input is determined by the rotation speed, while the heat time of plasticized materials is controlled by dwell time during FSRW process. In order to obtain FSRWed joints with excellent mechanical properties, welding heat input is taken as measurement standard, and the reasonable range of rotational speed and dwell time have been investigated by numerical simulation and statistics. The macroscopic morphology of 3 mm and 4 mm thick aluminum alloy 6061-T6 FSRWed joint we obtained shares uniform characteristic with the numerical simulation forming appearance whose upper surface tests smooth but exists “flashâ€, and stir zone, heat affected zone, thermo-mechanically affected zone and base metal four distinct zones can be observed in transverse section. The results of numerical simulation and experimental study show that the potential process we proposed takes advantages of solid-state welding and riveting technology. Not only metallurgical bonding can be obtained between upper and lower sheets, but also mechanical properties will be strengthened by riveting.
Design of a High-Gain Planar Lens Antenna Based on Metamaterial with Fan Beam
This paper presents the design and results of a planar lens fed by a fan beam H-plane horn antenna. Compared with traditional dielectric lens antenna, planar lens based on metamaterials is composed of several unit cells designed for changing the phase of incident wave. The presented lens is center-fed by a horn antenna located at 100mm from the lens, and the thickness of it is 5mm. The simulation results exhibits a high gain of 30dB at 76.5GHz and a fan-shaped main beam with half-power beamwidths of 1.7° and 4.1° on E-plane and H-plane respectively.
An Overview on the Main Technical Processes of Restriction-Site Associated DNA Sequencing (RAD-Seq)
Restriction site-associated DNA sequencing (RAD-seq) is a critical enabling genotyping method based on whole-genome restriction sites developed on the basis of second-generation sequencing and nowadays is widely applicable to a variety of biological problems in many species where traditional cytogenetic methods have failed. As sequencing costs have dropped, RAD-Seq has moved from being primarily a SNP discovery tool to being a method for high-throughput genotyping of populations. In this paper, the main technical processes of RAD-seq has been briefly summarized and great potential will been hold to clarify more development and application in researches.
Application of Bertalanffy and Logistic Growth Curve Fitting Model in Chicken
China is one of the most abundant chicken resources in the world. The local chicken breeds in the "Chinese livestock and poultry genetic resources Chronicles" have reached 107. In this paper, the nonlinear growth models have been briefly summarized and recent advances studies using Bertalanffy and Logistic Growth Curve Fitting Model in Chicken have also been reviewed. The significance and problems existing in the study of Bertalanffy and Logistic Growth Curve Fitting Model in Chicken in terms of future chicken research and breeding work were also discussed.
The Influence of Different Blade Outlet Angle and Wedge Groove on the Performance of the Double Suction Pump
This study aims to significantly improve the performance of the centrifugal pump by designing a wedge grooves on the outside of the impeller cover, and investigating the method for determining the blade outlet angle that plays important roles in the energy conversion. The solidliquid two-phase flow fields with the designed pump and an original pump were numerically simulated in the ANSYS-FLUENT. Compared with the original pump, reducing the blade outlet angle can effectively improve the sand-water wear on the blade surface and opening wedge grooves can slow down impeller ring wear. The head of the improved model pump decreases by about 1.5% and the efficiency increases by about 1.5%.
Utilizing Electrospinning to Construct Dual-Layer Dual-Anisotropic Conductive Janus-Structural Film with Magnetism and Green Luminescence
A dual-layer dual-anisotropic conductive Janus-structural film (DDCJF) with magnetism and green luminescence is fabricated by electrospinning. Two layers are tightly bonded together into DDCJF. The top layer is Janus-structural film with left and right structure using Janus nanobelt as building unit, and bottom layer is non-array film using nanofiber as building unit. In top layer, the nanobelts in the left and right regions are arranged vertically, which leads to mutually perpendicular of conducting directions, thus forming the dual-anisotropic conduction. DDCJF has adjustable magnetism, luminescence and dual-anisotropic conductivity. On the micro level, using Janus nanobelts as building units renders DDCJF excellent fluorescence properties and high degree of anisotropy. Macroscopically, the design of dual-layer structure can avoid the performance influence between top and bottom layers. The property of each layer of DDCJF is relatively independent due to the peculiar duallayer Janus structure, successfully realizing integration as well as isolation in the DDCJF.
Construction of Semi-Bianisotropic Conductive Janus-Structure Membrane Offering Magnetism and Fluorescence by Utilizing Different Functional Blocks
A new concept of semi-bianisotropic conductivity is put forward based on modularization design. Half of the material has dual anisotropic conductivity while the other half has single anisotropic conductivity by adjusting areas of the two surfaces endowed with anisotropic conductivity and vertically arranged up to down. Semibianisotropic conductive Janus-structure membrane affording magnetism and fluorescence (SCMF) is prepared by constructing three blocks via electro-spinning. Three blocks, including C-R block (top), M-G block and C-R block (down), are assembled into SCMF. Janus-structure nanobelts are selected as building units to gain micro zoning. Modular structure further prevents negative interactions among various functional substances. SCMF has bicolor luminescence and variable magnetism. SCMF gains tuned semi-bianisotropic conductivity, where the area of C-R block (top) with single conductive aeolotropism is half of C-R block (down) with single conductive aeolotropism, so half of SCMF has double conductive aeolotropism and other half of SCMF has single conductive aeolotropism.
Synthesis and Luminescence Properties of Mn4+ Doped K2sif6 Red Phosphor
A red phosphor, K2SiF6:Mn4+, was prepared by the hydrothermal method. The as-obtained K2SiF6 was confirmed as cubic phase. In K2SiF6:Mn4+ red phosphor, the strongest excitation peak lies in 350 nm and the strongest emission peak lies in 632 nm which is due to the 2Egâ†’4A2g transition. The optimum luminescence conditions were obtained by changing the Mn4+ doping concentration. Employing K2SiF6:Mn4+ with blue chip and commercial yellow phosphor fabricates a white-light LED. The asobtained white-light LED has low color temperature (3740 K), high color rendering index (86.4) and lumen efficiency of 166.02 lm/W, indicating that K2SiF6:Mn4+ can be used in warm white-light LED.
Advances in Simulation Research for Thermal Runaway of Lithium-Ion Batteries
Safety issue is main obstacle for commercialization of high energy density lithium-ion battery. Thermal runaway is the most crucial problem in battery safety research. In order to solve safety problem, a lot of efforts have been made in the research of battery thermal runaway mechanism, thermal stability test, simulation and modeling. Herein, this article provides a review on chemical reaction of thermal runaway and the development of thermal simulation research on lithium battery. Thermal runaway are mainly divided into four types according to reaction mechanism, having different heat-generating behaviors. Researchers can reduce the cost and time of experiments through modelling of lithium-ion batteries, analyze the key factors of the thermal runaway during charge/discharge process, and improve the structural design and safety of the batteries. Finally, the review
Molecular Dynamics Simulation and Analysis the Primary Radiation Damage of 4H-Sic Crystal Material Induced by 10kev Si PKA Under Different Temperature
Based on the molecular dynamics method and the simulation toolkit LAMMPS, the distribution characteristics of PKA tracks and the different kinds of point defects in 4H-SiC crystal material induced by 10keV Si PKA with specific incident direction under different temperature conditions were simulated analyzed in this paper. The mechanism of the counts of the various point defects changed with time under a certain temperature (300K) condition is compared and analyzed. Simulation and analysis of the spatial distribution of point defects in the stable stage with PKA track and temperature changes. The results of this paper provide an important basis for further exploring the formation mechanism of 4H-SiC radiation displacement damage defects, predicting the thermodynamic properties of 4H-SiC matrix materials by displacement damage, and the electrical characteristics of 4H-SiC devices/detectors.
Computation of Kirchhoff Index in Generalized Ladders
A connected graph G is viewed as an electrical network N by replacing each edge of G with a unit resistor. The Kirchhoff index of G is a structure-descriptor based on effective resistance of N. The generalized ladder is a subdivision graph of ladder graph. By using the properties of the Chebyshev polynomials, Laplace Theorem and so on, we obtained closed form expressions of Kirchhoff indexes for the generalized straight and generalized cyclic ladders, which generalize the results of linear quadrangular chain and linear hexagonal chain.
Game Analysis of Privacy Protection Based on Nash Equilibrium in Big Data Environment
Big data analysis has brought convenience to all fields of human life. At the same time, the problem of privacy leakage follows. Protecting user's private data and preventing sensitive information disclosure become urgent problems. However, big data has the characteristics of large amount of data, diversification of types and sources and rapid growth, so the traditional privacy protection technology is more and more unsuitable. The traditional privacy protection mechanism protects the privacy of users, at the same time, it will inevitably reduce the data utility[1]. On the basis of differential privacy knowledge, based on the Nash equilibrium privacy protection mechanism, this paper constructs an interrelated differential privacy model, analyzes and evaluates the game model among multiple data publishers, and proves the correctness of the game analysis.
Two Support Vector Machine Methods for Image Noise Filter
To solve the fatal limitation of SVMs based on the pre-known, two new image noise filter methods - Support Vector Machine based on self-learning machine (SLM-SVM) were presented, which is working better than many other non-linear filters, such as median filters and adaptive filters. A series of comparison and working parameters would be explained, performance of test showed these methods can dealing with the noise in a totally unknown image. And filter out more than 99% noise pixels from an image. In the same time, this kind of filter is still immature due to its long runtime (more than 2 second) and some error cases during testing, some recommendation and prediction were proposed.
Calculation of Soil Natural Temperature Field in Cold Region and Analysis of Influencing Factors
Soil properties directly affect the temperature change of crude oil in buried pipelines in cold regions, and clarifying soil temperature field and its influencing factors is the key to production management in gathering and transportation field. In this paper, a mathematical model for calculating soil natural temperature field was established to analyze the influence of frozen and unfrozen soil physical properties on soil natural temperature field, and to clarify the influence of soil physical properties parameters on soil temperature, delay time, freezing time and starting time of freezing, so as to provide theoretical support for thermal calculation of buried pipelines.
Research on the Construction of Campus Security Information Platform
As an education base, colleges and universities provide a large number of excellent talents for the country and the society. Campus security is bound to be highly valued by all sectors of society. However, current campus security incidents occur frequently and often appear in the media at the first time, which is easy to arouse wide attention of the society and the government. Because of its particularity, universities will face greater challenges when security incidents occur. Taking Tsinghua University as an example, this paper discusses the construction of an information platform for comprehensive security on campus, so as to make up for the deficiencies of traditional civil air defense and physical defense, better guarantee the safety of all kinds of school personnel, and provide reference for other colleges and universities to build a comprehensive security information platform.
Design and Research on Big Data’s Smart Ideological and Political Classroom in Colleges and Universities in the New Era
This paper introduces the significance of big data intelligent ideological and political education research in Colleges and universities in the new era, summarizes the research status of key technologies of Ideological and political education in Colleges and universities, and puts forward the concept of big data's intelligent ideological and political education classroom in Colleges and universities and key technologies of its model. Combined with the background of "a board of chess" epidemic prevention and control, taking Yunnan Normal University's education informatization and students' Ideological and political education work management as an example, this paper exemplifies "class suspension and keeping teaching" the working mechanism of big data's intelligent ideological and political classroom model in Colleges and universities and part of the front-end interface display are given, which provides reference for the research of big data's ideological and political education work and education information data center "a board of chess in the whole school".
A Running Pattern Recognition Algorithm for Publish/Subscribe Distributed Systems
Publish/subscribe distributed systems are often used in critical applications. It is necessary to monitor their running patterns in real time to detect abnormal status. Therefore, identifying the normal running pattern is the precondition of monitoring publish/subscribe distributed systems. Based on Apriori algorithm, this paper presents a weighted frequent itemset mining algorithm for running pattern recognition of publish/subscribe distributed systems. By introducing the transaction matrix, the algorithm only needs to scan the transaction database once. By weighting the items from two aspects of influence and frequency, the support of the items with few occurrences but much importance can be improved, so that the running pattern containing small frequency events can be mined out. Experimental results show that the algorithm can effectively mine the running patterns, and has better performance than Apriori algorithm and FP-growth algorithm.
Solving the Nominal-the-Best Decision-Making Problem by Grey-Fuzzy Linguistic Method
This article combines two well-developed notions: the grey relations method (GRM) and fuzzy linguistic scoring technique, for solving the problem of qualitative and quantitative criterions coexistence due to the original GRM being unable to effectively handle the simple qualitativeorientated solution. Further, an empirical process adopting GRM with the fuzzy technique has successfully proved the ratings of every alternative with two types of objectives can be an optimal approach. This conclusion can be utilized to help solve other related computing issues.
A Path Loss Statistical Model for On-Body WBAN
Wireless Body Area Network (WBAN) is a new and promising wireless communication technology which consists several sensors around, on or even implant into human bodies to sense importance human physical signals. In order to erect and develop a robust WBAN, accurate modeling of the body-area network radio-propagation channel and understand the statistical characteristics in close proximity to the human body are required. In this paper, we focus on study the on-body to on-body WBAN path loss model, the environments factors are considered. The statistical parameters are extracted form measurements data, the proposed path loss model is validated through comparison with a measurement-based approach.
Cause Analysis of Weld Crack of Pressure Vessel Attached to Gas Injection Compressor
Through the technical analysis of many cracks and leaks occurred in the pressure vessel attached to the gas injection compressor during its long service period at high pressure, the chemical analysis, metallographic analysis, hardness measurement, finite element analysis and vibration monitoring of the three-stage outlet spherical tank were carried out. Finally, it is determined that the causes of the defects are the high hardness and stress values of the weld seam and heat affected zone of the nozzle, and the mechanical fatigue caused by the alternating load caused by the vibration of the unit.
Research on Industry Index Fluctuation of Stock Market Based on SV-T Model
In a complex market environment, it is important to describe and predict the volatility of returns in various industries. In this paper, after ADF stability test is conducted on the return rate sequence of building materials, real estate, medicine biological, non-bank finance, and communication industry, SV-T modeling is carried out, and the parameter estimation range of SV-T model is obtained by using MCMC method and Winbugs software. After ten thousand iterations, under the condition that the Markov chain of parameters obtained by Gibbs sampling method converges, the parameter estimation results of SV-T model are obtained. According to the parameter estimation results of SV-T model in each industry, the difference of investment risk and volatility predictability among five target industries is compared and analyzed.
Minimal Feedback Vertex Sets in Honeycomb Networks
A vertex subset of a graph G is called a feedback vertex set if its removal results in an acyclic subgraph. The feedback vertex numberï´ (G) is the cardinality of the minimum feedback vertex set of G , which is an important parameter of interconnection network topology. In this paper, we determine the feedback numbers of Honeycomb mesh n HM and Honeycomb torus n HT , i.e. 2 ( ) 9 / 2 15n/2 4 n ï´ HM ï€½ n ï€­ ï€« and 2 ( ) 9 / 2 9 / 2 2 n ï´ HT ï€½ n ï€­ n ï€« . Comparing these results with those of Zhou, we find thatï´ (H) is related to the boundary of Honeycomb network H .
Exact Solution of Yu-Toda-Sasa-Fukugama Potential Equation In (3+1) Dimension
This article solves the Yu-Toda-Sasa-Fukugama potential equation in (3+1) dimension [1-4]. First of all, we carry out the traveling wave transformation on the equation. Then, the equation can be transformed into integral form. At last, we use the complete discrimination system for polynomial [5-12] to obtain all exact solutions of the equation.
Research on IFML Modeling Considering Session Data
The IFML standard does not include the concept of session data, which makes it sometimes difficult for the IFML model to accurately describe the source, destination, formation, and sharing of data for various elements of the web application front end. By extending the IFML metamodel, this paper introduces three new concepts and elements: Session Data, Using Session Data Flow and Providing Session Data Flow. The Using Session Data Flow points from the session data element to the interaction flow element, indicating that the interaction flow element uses the session data. The Providing Session Data Flow points from the interaction flow element to the session data element, indicating that the interaction flow element initializes or updates the Session data. Case studies show that the introduction of these three new elements in IFML model will make the representation of other interaction flow elements more intuitive, accurate and logical.
Three Band Wearable Antenna Based on Artificial Magnetic Conductor
In this paper, a three-band wearable antenna with coplanar waveguide (CWP) feed based on an artificial magnetic conductor (AMC) is presented. The antenna consists of a monopole antenna with an array of 4×5 AMC cells, using polyimide as the substrate, with overall dimensions of 124 mm × 155 mm × 8.9 mm. Three open inverted triangles form an independent monopole antenna, with each open inverted triangle corresponding to one band. The AMC unit is composed of three regular octagons produces zero phase reflection at the center frequency of the corresponding three bands. The design operates at 1.8 GHz, 2.4 GHz, 3.5 GHz, can be used in all three LTE 1800/WLAN/WiMAX bands and be applied to widely integrated into a variety of wearable devices. The gain of the three frequency points increased by 10.1dB, 2.86 dB and 5.06 dB respectively. In this paper, the antenna has been simulated with different degrees of bending performance, as well as the analysis of the effect of human tissues on the performance of the antenna. The results show that the antenna has good bending characteristics.
Research on Engineering Exemplification Teaching Method in Linear Algebra Teaching
Linear Algebra is a very useful subject, which is widely used in many fields, such as cryptography, Computer graphics. Traditional teaching generally adopts deductive teaching method, which is not suitable for the cultivation of innovative talents. By comparing deductive and inductive teaching methods, this paper used a new teaching method— Engineering Exemplification Teaching Method. Starting from actual cases to help students construct new knowledge by themselves, and then applied it to real life, thus completing the transfer and sublimation of knowledge. Finally, through a specific content, we discussed the specific implementation of engineering exemplification teaching method.
Exact Solutions for the (2 + 1)-Dimensional Nizhnik-Novikov-Veselov System
Finding the exact solutions of nonlinear partial differential equations plays an important part in nonlinear problems. We use the complete discrimination system for polynomials [1-6] to get exact solutions for the (2 + 1)-dimensional Nizhnik-Novikov-Veselov system in this paper. We divide different situations to discuss the solutions and get three kinds of solutions.
A Study on Total Energy Production, GDP, Total Investment in Fixed Capital and Population in Shandong Province
This paper is to aim at analysing the responses of total energy production from the impulses of GDP, total investment in fixed assets and population in Shandong. The impulse response function analysis indicates that Shandong energy production will be greatly influenced by the GDP impulses in the short run and the influences from total investment in fixed capital assets is the smallest in the short run. The influence of total energy production by the population is rather medium compared with the GDP and investment in fixed capital assets. So we can see that GDP growth will greatly influence total energy production. It is necessary for administration to pay attention to the GDP growth as concerning the planning of total energy production.
A Study on the Shandong Utilized Industrial Solid Waste Based on VAR Model
This study is aiming at analysing the relationship among the utilized fixed industrial solid waste, GDP growth and the R&D expenditure in Shandong. The results show that Shandong GDP growth will have a positive influence upon utilized fixed industrial solid waste and Shandong enterprises’ R&D expenditure growth will have positive influences too. Granger Causality tests indicate that Shandong's utilized industrial solid waste helped push the GDP development and Shandong enterprises R&D expenditure also helped push the Shandong GDP development. We can also see that government policies concerning encouraging the enterprises investment in R&D are also good for the sustainable development.
Review of Research on Big Data Technology in the Field of Petroleum Exploration
In the era of big data, the rich data resources of the petroleum industry not only provide auxiliary decision-making support for the production and scientific research of petroleum enterprises, but also play a vital role in the digital transformation of enterprises. From the perspective of petroleum exploration data management technology, this paper divides its past development process into database technology stage, data warehouse technology stage, data lake technology stage, data integration platform stage, and special application of big data technology by combing the relevant literature. At present, it is in the initial stage of the construction of the data middle office. The core problem that needs to be solved is to match the calculation type with the most suitable computing framework, optimize the allocation of computing resources, and give full play to the processing capabilities of the data middle office.
Investigation and Analysis of Residents’ Willingness to Sort Garbage in Harbin
In order to study the influencing factors of residents' willingness to classify garbage in Harbin, countermeasures and suggestions are made according to the analysis results of the influencing factors. In this paper, questionnaire data were obtained by combining field questionnaire distribution and online questionnaire distribution in Harbin. SEM was used for correlation analysis of questionnaire data. The analysis results showed that age and income had a significant positive impact on residents' willingness to classify garbage, and older female groups were more familiar with garbage classification and more willing to conduct garbage classification. Based on the analysis results, this paper puts forward feasible suggestions for Harbin to implement the garbage classification policies.
A Design Scheme of Smart Energy Internet
Breaking through the limitations of traditional power grid, photovoltaic panels, air source heat pump, ground source heat pump, lithium battery energy storage system, intelligent charging pile and other equipment are installed on the roof of ChengBi campus, and the energy consumption of dynamic distribution units is monitored through the energy management system. To realize the protection of new energy and ecological environment.
Study on Parallel Current Sharing Technology of Power Module in DC Charging Pile for Electric Vehicle
In order to meet the changing requirements of multiple types of electric vehicles, the layout and development of quick charging and DC charging piles are rapid. The modularized DC charging pile becomes the popular research field. Due to the differences in the parameters of each module in the charging pile, the current assumed by each module in parallel may not be the same, leading to the premature aging and damage of some modules and affecting the service life of the charging pile. In this paper, the isolated full-bridge DC/DC converter is taken as the power module topology, and the parallel current-sharing technology is studied. Two control methods are designed, one is the double-closed-loop cascade control of the voltage outer loop and the current inner loop, and the other is the adaptive double-loop based on charging mode. The current-sharing loop is added in the two controllers and the averaging-current method is adopted and the simulation verification of two-module and four-module in parallel is carried out. Through the comparison of load switching, the advantages of the he adaptive double-loop control method in the multimodule parallel connection, such as large stability margin and fast response speed, are validated.
Flexible Power Distribution Technology Based on Modular DC Charging Pile
With the rapid development of electric vehicle industry in China, the contradiction between the increasing users' demand for real-time charging and the unbalanced planning and design of charging piles is increasingly apparent. DC charging pile on the market is developed rapidly, but its structure is with multi-gun to one-pile. It is difficult to meet the demand of different kinds of electric vehicle battery charging, different battery capacity and the user expected charging time. To solve the problems, a flexible power distribution method of DC charging pile is proposed in this paper. When multiple EV in different types and states are charged at the same time, and the actual charging demands of each user and the charging battery are considered, the power module can be dynamically switched to realize the flexible power distribution, the idea of flexible power distribution is described. Then the algorithm steps of power distribution were presented. Finally, the Matlab/Simulink was used for example analysis to simulate the power distribution process when different initial SOC batteries were charged simultaneously.
A Correction Model of Troposphere Delay for GNSS Signal in the Dust and Haze Weather
Tropospheric delay is a factor that affects GNSS positioning accuracy, and the instability of the tropospheric refractive index is the cause of the deviation of tropospheric delay compensation. In the case of taking into account the atmospheric water vapor content and the atmospheric temperature of the station, this paper simplifies the establishment of a parametric refractive index correction model to replace the refractive index model that depends on meteorological factors. The parameters of the correction model are determined by the tropospheric layering method. The results show that under the same weather conditions, the accuracy in northern Shaanxi is higher than that in Guanzhong, and the correction value of refractive index is not ideal when it is far from the ground. Based on the model to estimate the ZTD, the results are compared with the results obtained by three IGS stations (LHAZ, BJFS, SHAO), which confirms that the accuracy of the ZTD estimation is generally improved by the model.
Sustainable Improvement of Water Quality in Urban River Network by Rotating Overflow Weir—Case Study of Changzhou City in China
Water diversion is a practical and commonly used approach to improve the water quality of rivers in urban plains in China. This paper researches using rotating overflow weirs as the primary engineering solution to facilitate water diversion and improve the water quality of the river network in urban plain area of Changzhou, including hydrodynamic modeling, field tests, and application. The water diversion scheme, including clean water source, water transfer paths, quantity, and rate, was designed based on its current terrain and river systems. The Yangtze River was selected as a high-quality water source, and its two tributaries were utilized as clean water paths. Four rotating overflow weirs were proposed to create three stages of hydraulic gradient. Clean water can flow naturally and orderly in the researched urban river network without pumps. The required clean headwater level and clean water distributions were modeled hydrodynamically. Four temporary weirs were constructed at design locations to conduct field tests. And the water diversion scheme and its water quality improvement had been verified by field tests. Afterward, four permanent rotating overflow weirs were built. Currently, the monitoring results show the design water transfer scheme reaches expectations. The flow velocity in most rivers has been increased to 7cm/s from standstill in Changzhou's main urban plain area. The composite water quality of 93% river cross-sections monitored has been improved from Class V to Class â…¢ and all have been improved to Class IV and above.
Promote the Development of Integrated Energy Service Industry with Platform Mode
In recent years, integrated energy service industry has entered a stage of rapid development in China. Quantities of domestic energy companies and technology companies have deployed and expanded integrated energy service businesses. Moreover, integrated energy services based on the platform model is currently a development direction that has attracted much attention. This article analyses the development status and trends of the domestic platform market of integrated energy service. We also study on the functional positioning and development mode of building an integrated energy service platform. Then we propose the main services functions and business scenarios of the platform. Finally, this paper puts forward relevant suggestions to promote the development of integrated energy service industry platform.
Master-Slave Design and Control of Five-Finger Dexterous Hand Based on Tendon-Sheath Transmission
In order to make the dexterous hand more lightweight and anthropomorphic, a 19-joint anthropomorphic dexterous hand driven by the servo through the Tendon-Sheath transmission was designed. First, the configuration of the dexterous hand is determined with reference to the joints of the human hand, and the decoupling and driving of the joint motion are realized through the Tendon-Sheath transmission, and the joint mechanism and the driving integration are designed respectively. Then, based on the bending sensor and master-slave mapping algorithm, the grasping master-slave tracking control is realized. Finally, a dexterous hand prototype is built, joint motion experiments and grab control experiments are carried out. It can be seen from the experimental results that the designed dexterous hand has high movement flexibility, and the cooperation of each finger can realize the effective grasping of objects such as water bottles and apples. The experimental results show that it is feasible to apply the Tendon-Sheath transmission to the dexterous hand. Based on the master-slave control, the dexterous hand can grasp various objects.
Analysis and Verification of Dynamic Characteristics of Flexible Spatial Parallel Robot
To study the dynamic characteristics of the flexible 3-RRRU spatial parallel robot, the coupling dynamic model of the 3-RRRU spatial parallel robot with both rigid and spatial flexible links in the kinematic chain was established by Adams software. In order to verify the correctness of the established coupling model, the positive kinematic results of the fully rigid 3-RRRU spatial parallel robot and the flexible 3-RRRU spatial parallel robot are compared and analyzed. Based on the coupling model, the driving torque, elastic modulus, and stress are discussed. And the effect of stress distribution on the flexible 3-RRRU spatial parallel robot. The results show that under the same conditions, the trajectory of the geometric center of the end-effector in the two types of models is basically the same, but due to the elastic deformation generated by the spatial flexible link, the trajectory of the end-effector in the coupled model in the x, y, and z directions will fluctuate. The maximum floating values are 3.57 mm, 2.96 mm and 2.05 mm; respectively, therefore, a reasonable modeling of rigid-flexible coupling spatial parallel robots is essential. It can be seen from the coupling model that the maximum stress of the system is mainly concentrated on the geometric center of the spatial flexible link and the joint connected to the rigid link, and the driving torque is asymmetry, which provides a data reference for structural optimization; the greater the elastic modulus, the more obvious the coupling effects, which leads to the enhanced system oscillation.
A Study on the Kinematics of the Model Support System of the Dual-Machine Wind Tunnel Test
In the dual-machine wind tunnel test, the rear machine model support system is an open chain mechanism composed of rigid links in series with rotation and translation functions, and belongs to a multi-rigid body link system. The kinematic analysis of the system is to use the centroid of the posterior model as the end position of the mechanism, and analyze the relationship between the position and posture of the centroid of the model and the space of each joint variable. [1] Therefore, in order to study the motion control system of the model support system and the dual-camera pose simulation, the kinematics analysis of the back-machine model support system is first required. Based on this analysis, a cloud image of the working space of the model support mechanism is established to ensure that it does not collide with the side wall of the wind tunnel.
The Extraction of Product Assembly Feature Information for Intelligent Assembly Sequence Planning
The assembly feature information contained in the CAD model of the product is an important basis for the generation of intelligent assembly sequence. Taking the assembly model of the product as the research object, the research on the acquisition of assembly feature information of the product by intelligent assembly sequence planning is proposed in this paper. Microsoft Visual Studio 2005 and SolidWorks API are used as implementation means to access the internal data of the product CAD model and realize the extraction of the hierarchical information, mating relation and mating line and surface assembly features of the assembly model. An application example of product assembly feature information extraction for the locking device of an elevator landing door shows that the established method of acquiring product assembly feature information is effective and provides a theoretical and technical basis for the establishment of product design and assembly sequence planning knowledge base.
Research on the Development of Chongqing’s Intelligent Industry Based on the Background of China’s High-Quality Economic Development
As an important direction of industrial development, intelligent industry will be the key to upgrade industry and create a new engine for economic growth. Discussing the development of Chongqing’s intelligent industry based on the background of China’s high-quality economic development not only meets the requirements of local development strategies, but also verifies the guiding role of high-quality development theory of industrial development. Through the analysis of the development status and existing problems of Chongqing’s intelligent industry, and then propose suggestions for accelerating the development of Chongqing’s intelligent industry combined with high-quality development connotations.
Communication Equipment Maintenance Decision Method Based on Equivalent Service Coefficient
In order to solve the problems of time-consuming, laborconsuming and low accuracy of manual statistical calculation of maintenance interval in current communication equipment operation and maintenance management, a communication equipment condition based maintenance decision-making system based on real-time condition monitoring is proposed. Based on the actual operation status information data of communication equipment in the real-time database, the system uses the life prediction calculation method of communication equipment related components to calculate the service life (operation hours and startup times) under the current state, convert it into the equivalent service life under the benchmark operation conditions, and then compare it with the maximum maintenance life to predict the remaining life Based on the product of maintenance coefficient and service coefficient of line hours and startup times, the concept of equivalent service coefficient is proposed. According to whether the equivalent service coefficient of operation period and forecast period is equal, four maintenance decision-making models are established, and then the specific maintenance opportunity of communication equipment related components is determined.
Research on Facial Expression Recognition Algorithm Based on CNN
In order to realize the recognition of facial expression quickly and accurately, the traditional convolutional neural network is improved in this paper, and the research of facial expression recognition based on LeNet-5 convolutional neural network algorithm is proposed. Firstly, the image is preprocessed, including normalization and geometric transformation. Secondly, the convolution neural network model based on LeNet-5 model is designed, in which the Flatten layer is added, the Dropout strategy is introduced, and the LeakReLU is used as the activation function. At last, the experimental results show that the recognition rate of the improved algorithm is better than that of LBP, sift and hog, but it takes the longest time and the largest amount of computation.
Identification and Suppression in Flying Synchronous Emergence of UAV Clusters
Vicsek model is used to simulate the moving behavior of a UAV (Unmanned Aerial Vehicle) cluster, and the flying synchronization process of a UAV cluster is observed by different emerging measurements and the cooperative process of a UAV cluster is interfered at the right time.
Sound Source Acquisition and Location System Based on DSP and FPGA
According to the requirements of audio signal acquisition and conversion, sound source location in complex environment, a sound source collention and positioning system which based on DSP and FPGA is designed. The system adopts low noise MEMS microphone sensor to form microphone array, DSP chip as the core controller, beam forming algorithm as the core algorithm of the system. Through the application of high precision ADC chip to carry out synchronous sampling and conversion of 64 channels of audio signals, simultaneously, the use of low-cost, high-speed FPGA chip to achieve batch data acquisition and caching. The real-time data upload is realized by fast Ethernet controller to ensure the non-blocking transmission of large traffic data. Through the laboratory test, the analysis and verification of the experimental data, the system works stably and meets the design requirements.
Weighted Sum Synchronization of Stochastic Delayed Memristive Neural Networks via a Novel Hybrid Control
This paper investigates the weighted sum synchronization issue of stochastic delayed memristive neural networks (SDMNNs) via a novel hybrid control (HC). The switching strategy is applied to the controller to cope with the challenges induced concurrently by impulses, stochastic turbulence and time-varying delays. Furthermore, the control costs can be reduced by using this designed controller. Finally, novel Lyapunov functions and new analytical methods are contructed, whic can be used to realize the weighted sum synchronization of SDMNNs via HC.
An Efficient and Stable Grasp Planning Method for Stacked Parts
In the industrial scenes, it often requires to pick up the part quickly in part stacked scenes and then place it in the specific position. This paper proposes a method of grasp evaluation function for grasp planning. It considers collision and interference between gripper and other objects, relative height, grasp angle of the object and stability of grasping the object. In addition, we use the method of voxelization to describe the scene. The research team builds a robotic arm grasping system based on ROS, UR3 and Ensenso N35. We carry out grasp experiments on the stacked scene of a single kind of object. The accuracy is 79.55%. It takes 3.6 seconds to get a grasp pose, which basically meets the requirements of industrial use.
Fault Diagnosis Method for Joint Motor Inverter Power Tube of Live Working Robot
The joint motor of live working robot adopts brushless DC motor system. Because of the interference of unstable factors in working environment and the vulnerability of power electronic devices, inverter power tube is the most vulnerable link in the system. Based on the model of brushless dc motor system and simulation analysis of the open circuit fault mode of inverter power tube, this paper summarizes the distortion characteristics of the three-phase current waveform of inverter power tube output. An open circuit fault diagnosis method for inverter power tube based on the variation of three-phase current waveform is presented, and the correctness and feasibility of the method are verified.
A Time-Domain Finite Difference Decomposition Method for Boulders in the Cultivated Layers Based on Ground-Penetrating Radar
Afinite difference time domain (FDTD) model of the electromagnetic wave of the two-dimensional Maxwell's discrete equation is established, based on the optimization of the Ground-penetrating radar (GPR) antenna frequency (recommended 100MHz), time window length, and sampling interval parameters. In our study, three test schemes are designed: The electromagnetic wave enters the boulder medium from the soil to have the first reflection (top reflection) when a boulder point appears in the homogeneous soil, and then passes through the boulder in the water and re-enters the soil. The secondary reflection (bottom reflection) is generated, and radar image interpretation shows that the size of the boulder is the same as the designed size (0.5m).Then, the interference phenomenon of the reflection waves of the two boulders can be simulated when two boulders appear in a homogeneous soil, and the spatial position and size of the two boulders can be distinguished. For the cultivated soil layer with obvious horizontal stratification, the upper soil layer does not affect the reflection of the boulder when the boulder is located in the lower layer, and the location and size of the boulder can still be accurately interpreted. Numerical test results show that the FDTD method is a very effective method to forward simulate the boulder phenomenon in the cultivated soil layer, which has the advantages of simple principle, high simulation accuracy and fast calculation speed.
Optical Lens Edge Detection Method Based Coaxial Alignment Micro Assembly
Optical lens assemblies are key to affecting lens accuracy. The coaxial alignment could improve the accuracy of lens assembly effectively in automatic assembly system. But it was difficult to capture the full edge of the lens in one image because of the limit of the CCD camera field of view and the image edge of the lens is not sharp. The purpose of this paper is to propose an edge detection method of optical lens based on Holistically-Nested Edge Detection (HED) for a micro-assembly system with coaxial alignment function. First, the edge of the optical lens is got by HED method, and then the thick edge of the detected optical lens is refined image and the pixel points in the middle position of the thick edge of the recognized image is extracted. Finally, the least square method is used to fit the edge image of the lens. The results of comparative experimental shows that this method which can extract edge of the optical lens image automatically is more robust and more accurate than the previous edge recognition methods.
Research on the Algorithm of Air Combat Game Strategy Based on MCTS
Aiming at the complex problem of make a decision on the game strategy of air combat, this paper analyzed the air combat situation advantage value such as the angle and distance of combat aircraft by the battlefield situation, built the ail combat game model. Monte Carlo tree search algorithm is used to select the best game strategy. The experiment result shows that the model and the method are correct and effective and can search out the optimal game strategy in the huge game strategy space quickly.
Knowledge Graph Construction for Electric Power Science and Technology Achievements
The management of power technology requires great effort and cost due to its wide coverage and complex data types. However, under the current technical background of deepening informatization degree, negative effects such as large information redundancy and ambiguous information makes it facing greater challenges. Based on this, this paper proposes to realize the effective management of electric power science and technology information by means of knowledge graph. We use the data of electric power science and technology achievements from 2005 to 2018 to build the knowledge graph through the knowledge graph building platform, so as to provide effective management methods for the management of electric power sci-tech achievements
Knowledge Reasoning Model for Social Security
A large amount of social event data in the public safety filed has been accumulated. These data contains a lot of hidden information that has not been excavated. In order to make these data mined and fully utilized, this paper uses knowledge reasoning technology to solve this problem. This paper adopts a model SSKR-T based on the transfomer network structure, and conducts experiments on public data sets. The results show that the model has excellent reasoning effects in the field of social safety.
Yingliang Knowledge Reasoning Model for Huang
Public Safety Knowledge Graph using Bilstm- Attention-CRF and Multi-Source Data
Public safety has always been a hot topic in the world, yet related data are stored in various forms of structures and have a huge amount. The poor characteristics of these huge amounts of heterogeneous data bring great difficulties to its application. For the purpose of applying these data conveniently and efficiently, knowledge graph was adopted. Public safety knowledge graph can help organize public safety data by an organized and properly utilized form, so that it can be used more optimally in public safety related retrieval, question and answer systems, etc. In this paper, unstructured, as well as structured public safety data were used for constructing, with the support of BiLSTM-Attention-CRF model. To be able to reveal this public safety knowledge graph in an understandable way, Neo4j database was used to store public safety knowledge graph.
Underwater Target Ranging and Sound Speed Profile Inversion via Eigenray Propagation Time-Delay Matching
An underwater target ranging and sound speed profile (SSP) inversion algorithm for synchronous beacon is proposed. In the condition of actual SSP unavailable, based on the multipath propagation time-delay estimation, a genetic algorithm is employed to estimate the target range and SSP by eigenray propagation time-delay matching. Lake trial results show the algorithm could achieve target ranging and SSP inversion simultaneously.
An Electrical Power Text Entity Extraction Method Based on BERT Model
Most important electrical power information on the Internet is hidden in natural language text and is difficult to be directly processed by the computer. In this paper, an electrical power text entity extraction method is proposed to extract the key electrical power information that people need from a large number of natural language texts. The extraction of power entities provides a large amount of data for the establishment of the power knowledge graph, which facilitates the daily life and industry production. In this paper, the method is tested and evaluated on the text data of power science and technology achievements, which proves that electrical power text entity extraction method has high accuracy.
An Underwater Acoustic Positioning Algorithm for Single Beacon with Slow Varying Ranging Deviation
Underwater acoustic ranging error results from varied causations which make it diverge from Gaussian distribution and bring about low-precision EKF results in range-only positioning and navigation algorithm. A slow varying ranging deviation model is proposed here, the ranging deviation comprises gaussian noise and non-gaussian slow varying deviation. Then an improved EKF (IEKF) algorithm and the initial state value determining method are brought forward. Simulated experiments and lake trial are conducted, results show that IEKF could tracing and compensate the ranging deviation, thus achieves better precision than conventional EKF.