This paper presents an interface scheme for the multiplexing transmission of multi-channel and two-wire sensor in the analog/digital signal circuit of the system. The scheme adopts the master-slave information transmission architecture, and the host unit can extend and connect up to 256 two-wire audio signal acquisition terminals. The intelligent audio signal acquisition terminal accepts the digital instruction of the main control unit online through signal multiplexing line technology while collecting the audio analog signal, and realizes the online programming, self-calibration and fault self-diagnosis functions of the audio signal acquisition terminal, which improves the information and intelligence level of the system to a great extent. This technology has been successfully applied to boiler pressure pipeline leak detection system.

Aiming at the shortcomings of the traditional communication mode of heating system in China, such as low data transmission efficiency, high maintenance cost and poor applicability, a district heating monitoring system based on Lora wireless communication technology was designed.The system carries out data transmission through the terminal and gateway equipped with Lora, and uploads the data of each heat exchange station to the master station for real-time monitoring, so as to realize the centralized intelligent management of heat exchange stations.

COVID - 19 since the outbreak, the national colleges and universities is facing in the special period complete teaching tasks, such as office, the traditional work of colleges and universities under the informatization service in colleges and universities can't meet the demand, in this context WeChat jilin institute of chemical industry information center based on the enterprise to carry on secondary development, realize the online teaching, online office, and real-time monitoring of the teachers and students health status, data sharing, and other functions.This paper analyzes the design process of informatization service platform of Jilin University of Chemical Technology under the Covid-19 epidemic situation, and plays a certain demonstration role.

At present, when the instant communication network covers the routing nodes, the poor connectivity of the routing nodes in the instant communication network results in the excessive energy consumption of the routing nodes in the network. Therefore, the optimization method of the routing node coverage control in the instant communication network is proposed. This paper analyzes the losses of routing nodes in the process of data transmission, determines the location of routing nodes; evenly divides the network into regions, evenly deploys anchor nodes, calculates the optimal distance between routing nodes, and covers routing nodes in the instant communication network; calculates the coverage and connectivity of routing nodes, determines the coverage area of routing nodes, and optimizes the coverage control of routing nodes. The experimental results show that, under the same parameters, when detecting the number of active nodes and the remaining energy in the network, the optimization method of routing node coverage control in this study, the number of active nodes in the network is large, and the running energy of the nodes in the network is enough to support the operation of the network, and also has the remaining energy.

Clustering algorithm is one of the hot research technologies in digital recognition. It is a kind of unsupervised learning method to look for clustering classes with similar features. Clustering method is used to design handwritten number recognition system in VC ++6.0 environment. Through image segmentation and feature extraction, pattern similarity measurement and clustering analysis, the recognition work is completed. The results show that the recognition rate of the handwritten number recognition system based on the clustering recognition algorithm can reach 100%, which meets the practical application requirements.

Aiming at the low accuracy of the current automatic rating system, which results in the error of the final physical fitness test rating result, an automatic rating system for the physical fitness test of male basketball players is designed. The physical fitness test hardware structure is designed, and the single-chip microcomputer as the processing core, the physical fitness data acquisition circuit structure is designed. After defining the physical fitness test data of male basketball players into different categories, a directivity parameter was set up to construct the physical fitness test rating algorithm. After setting the root node of programming, JAVA was used to realize the function of the rating software, and finally the design of the automatic rating system was completed. The results showed that the rating system designed in this paper had the smallest error in the rating results.

Aiming at the problem that the traditional running track monitoring system is easily affected by the environment, which leads to the poor accuracy of monitoring results, this paper proposes the design of running track monitoring system based on KNN algorithm. This study uses the RF sub module to capture the image captured by imx179 camera, control the sub module to process the image data, and transmit information through PCI bus, uses control sub module to process the image data and transmits information through PCI bus. In addition, the module of upper and lower computer is used to process track information, and the tracking results are displayed by indicator light, and KNN algorithm is used to recognize running posture and build running equation. The experimental results show that the maximum error of running trajectory monitoring in the front and back angles of the system is within the acceptable range, and the monitoring results have high accuracy.

The molecularly imprinted polymer coating fibers with 3, 4-dichlorophenylacetic acid as template molecule, methacrylic acid as functional monomer, ethylene glycol dimethacrylate as crosslink agent, 2, 2'-Azobis(2-methylpropionitrile) as initiator were obtained by in-situ polymerization method. And they were filled into a stainless steel needle to prepare the NTD for analysis of polychlorinated biphenyls in industrial wastewater. The synthesis conditions of molecularly imprinted polymer coating, such as functional monomer were optimized. Under the optimal conditions, the linear range of PCB28 and PCB52 was 0.02~500 μg/L, and that of PCB118, PCB153 and PCB180 was 0.05~500 μg/L. The correlation coefficient (r) was between 0.9912 and 0.9959, and the detection limit was between 0.0045~0.014 μg/L. The prepared NTD with molecularly imprinted polymer coating can selectively adsorb PCBs in complex samples with high extraction efficiency. The spiked recoveries were 90.89%~98.93% with relative standard deviations (RSDs) less than 9.3%.

As the stress relaxation is the primary cause for the flange connection failure, a type of new muti-cone coupling flange is designed to diminish stress relaxation for the flange connection. Researching on the structure and geometrical property of the new type flange is carried out in order to improve the connection property. Both the theory reasoning and the laboratory testing proved that the flange structure and machined tolerance have effect on the stress relaxation, which is significant for the flange designing, machining and checking.

The natural convetion of nanofluids in an inclined square cavity are numerically simulated by using Chebyshev collocation spectral methods. The left-hand and right-hand walls of the cavity were kept at a constant temperature, while the upper and lower walls were insulated. The magnetic field parallel to the lower wall of the inclined cavity is imposed. The cavity is filled with different nanoparticles, based on water. The effects of pertinent parameters such as the inclined angle of the square cavity, Grashof number and the solid nanoparticles on the fluid flow and heat transfer of nanofluids. The results show that the heat transfer of nanofluids is maximum when the inclined angle is p/4, while the heat transfer of nanofluids is restrained when the inclined angle is p/3. The fluid flow and heat transfer of nanofluids are a significant change with Grashof number. The influence of different nanoparticles on heat transfer is similar.

The labyrinth seal model of high speed gearbox transmission shaft was established. The standard k-ε turbulence model was used to simulate the flow field characteristics in the labyrinth seal, and the leakage, pressure and velocity distribution were analyzed. Simple algorithm in Fluent is used to calculate the energy equation and turbulence equation. By studying the influence of tooth pitch and tooth tip length on sealing performance, the optimal parameters were determined. At the same time, the influence of inlet pressure and speed on the leakage of labyrinth seal of gearbox was studied. The results show that the leakage increases with the increase of tooth pitch. With the increase of tooth tip length, the leakage quantity decreases at first and then remains basically unchanged. When the temperature rise condition is not considered, the speed has almost no effect on the leakage, but with the increase of the speed, the sealing performance improves.

Using the bionic coupling principle, the typical unit body is extracted, and the wear-resistant surface of nodular cast iron with better wear resistance can be obtained by laser melting technology. Through simulation, it is found that the stress concentration at the unit body and the stress reduction of the matrix appear on the bionic coupling surface. By compounding typical bionic structures and changing structural parameters, the stress magnitude and distribution of friction surface can be changed. The simulation research was carried out by using the software, and the following conclusions were drawn: The results show that for the straight line+involute composite bionic unit, when only the distance between straight lines is changed, the friction stress on the unit increases, while the friction stress on the substrate surface decreases, and the wear resistance of the material increases with the increase of the distance between straight lines. When the linear distance reaches 7mm, the friction stress on the substrate surface is the smallest and the wear resistance of the material is the best; When only the involute base circle radius is changed, the wear resistance of the material increases first and then decreases with the increase of involute base circle radius. When the radius of involute base circle reaches 0.5mm, the friction stress on the substrate surface is the smallest, and the wear resistance of the material is the best.

Aiming at the current situation of imperfect infrastructure and late start of alpine snowboarding, a new type of balance training device for skiers was designed to provide training equipment for the combination of snow and land. The device has the characteristics of simple operation, reliability, safety and accuracy. It can realize ± 15 ° swing around X axis, 360 ° swing around Y axis and ± 30 ° swing around Z axis. The strength of the athletes' muscle groups can be strengthened, the destructive force on the body balance caused by the change of the angle can be overcome, and the athletes' body balance ability and the control ability for the skis blade can be improved through the training on the balance train device. In addition, the finite element analysis of the transmission shaft, which is the key transmission part of the balance training device, showed that the maximum stress was 186MPa and the minimum safety factor was 3.36, which meet the use requirements.

In view of the lack of large-scale and high-efficiency seeder in the process of green manure hairy vetch sowing, we can only use manual sowing or general drill seeder. This paper designs a special seeder for green manure hairy vetch. The seeder can sow 7 rows at one time, the seed width is 3.3m, and the maximum sowing speed can reach 25km / h. The biggest feature of the planter is the combination of air compressor, rotary tiller and planter, which can complete the whole process of rotary tilling, sowing and covering soil compaction at one time, and solve the problems of uneven sowing, high labor intensity and low drilling efficiency in the process of green manure and hairy vetch sowing.

An elongated "rigid-flexible coupling" pneumatic flexible driver with compressed gas as the power source is designed. The driver adopts an inner and outer nested structure, with an elastic airbag inside and a restraining spring outside, which can effectively improve the rigidity of the driver. In order to study the influence of restraint springs of different stiffness on the statics performance of pneumatic flexible actuators, experimental methods were used to study the relationship between actuator axial elongation deformation, driving force and working air pressure with different spring wire diameters. The experimental results show that the extension of the actuator increases non-linearly with the increase of the working air pressure. Under the same working air pressure, the diameter of the constrained spring wire is negatively correlated with the extension of the actuator; when the elongation is zero, the actuator has an axial direction The driving capacity is the largest, and the maximum driving force of the actuators with different stiffness is the same, which is positively related to the working air pressure. This research provides a feasible solution for the further application of the elongated pneumatic flexible actuator in the soft robot.

Al-xMg₂Si alloy was modified with 0.5 wt.% Ca-Sb. With the decrease of Mg/Si content from 18 wt% to 14 wt%, the grain size of primary Mg₂Si in the unmodified alloy was refined from ~ 123 mm to ~ 15 mm, and the grain size of primary Mg₂Si in the unmodified alloy decreased from ~ 123 mm to ~ 12 mm When the content of Mg/Si in the alloy is reduced to 10 wt%, the microstructure of the alloy is composed of primaryα- Al + eutectic Mg₂Si. In Al-xMg₂Si alloy modified by 0.5 wt.% CA sb, dendrite like primary Mg₂Si disappears and transforms into fine polygon due to the effect of modifier. With the decrease of Mg/Si content from 18 to 12 wt.%, the grain size of primary Mg₂Si decreases from ~ 15 mm to ~ 5 mm, forming ultrafine primary Mg₂Si. The mechanical properties of the alloy were tested, and it was found that ultrafine primary Mg₂Si had a great effect on improving the mechanical properties of the alloy. The optimum alloy is Al-12Mg₂Si modified by 0.5 wt.% Ca-Sb.

In order to improve the level of resource sharing and scheduling in higher mathematics teaching, this paper proposes a design of advanced mathematics teaching assistant system based on particle swarm optimization algorithm. In this paper, the model of higher mathematics teaching resources fusion is constructed, and the adaptive scheduling of higher mathematics auxiliary teaching resources is realized by using the fusion particle swarm optimization algorithm. The autocorrelation feature quantity of higher mathematics auxiliary teaching resources is extracted. Through the fuzzy correlation feature matching and statistical analysis method, the adaptive optimization of higher mathematics auxiliary teaching resources fusion is realized, and the particle swarm optimization is carried out In the process, the combination of statistical features is analyzed and controlled to realize resource scheduling and information fusion, and improve the management ability of higher mathematics auxiliary teaching. The simulation results show that the teaching information resources integration degree of the designed system is high, the information scheduling ability is strong, and the management level of higher mathematics auxiliary teaching is improved.

The traditional method of solving nonlinear equations has many iterations and takes a long time. Therefore, a trust region algorithm for solving nonlinear equations is proposed. Firstly, the trust region algorithm model is established, the nonlinear equations are transformed into unconstrained problems, the iterative process parameters are determined, the Hessian matrix is established, and the approximate sequence is constructed. Then, the convergence analysis is carried out by using the counter argument method to verify the feasibility of the algorithm. In the simulation experiment, three cases are selected to verify the traditional algorithm and the algorithm proposed in this paper. The experimental results show that the results of the two algorithms are similar, but the iteration times, CPU time and function value are better than the traditional algorithm.

At present, the path optimization method ignores the penalty cost generated by the time window constraint of the customer, resulting in the high penalty cost and the inability to obtain the optimal distribution path. Based on this, an optimization method for the logistics distribution vehicle path based on the improved ant colony algorithm is proposed. Complete genetic algorithm combining with improvements on ant colony algorithm, the model of logistics distribution vehicle routing problem is the objective function of the path planning problem, and according to the actual situation of distribution process and the conditions of specific requirements to set the terms of the objective function, to calculate the cost of fixed and variable costs to provide judgment for path optimization, design the arithmetic flow path optimization problem. In the example analysis, the logistics distribution of a fresh enterprise is selected as the example. The experimental results show that the total cost of the optimal path obtained by the design method is much lower than that of the traditional method, indicating that the proposed method is more practical.

The demand dimension of rural leisure tourism tourists is affected by the service level of tourist attractions, and the analysis accuracy is poor. For the purpose of improving the accuracy of rural leisure tourism tourist demand dimension analysis, a rural leisure tourism tourist demand dimension analysis based on the theory of perceived value is proposed. According to the analysis of the demand dimension of rural leisure tourism tourists, the demand dimension analysis equation of rural leisure tourism tourists is fitted and processed, the demand dimension coefficient of rural leisure tourism tourists is corrected, and the demand dimension analysis equation of rural leisure tourism tourists is established. Through the analysis process of the demand dimension of rural leisure tourism tourists, the analysis of the demand dimension of rural leisure tourism tourists is realized. The experimental results show that the tourist demand dimension analysis method based on the theory of perceived value has high analysis accuracy of the rural leisure tourism tourist demand dimension regardless of high service conditions or low service conditions. In practical applications, this method can be used accurately. Analyze the demand dimension of rural leisure tourism tourists and improve the satisfaction of rural leisure tourism tourists.