Taking the main bridge of Shuinan Bridge as the research object, the large-scale general finite element program MIDAS/Civil was used to establish the spatial finite element calculation model of Block 0 of the pier, and the stress of Block 0 under the construction stage and the operation stage of the bridge was analyzed. The calculation results show that except for the slight weakness of the diaphragm manhole part, the rest of the pier No. 0 block meets the specification requirements, and the calculation results have provided a basis for the design of the bridge, and also have certain reference value for the design of block 0 of similar bridges.

Through the bending test of PHC500AB(100) prestressed pipe pile, the occurrence, development and deformation characteristics of pile cracks under bending of pipe pile were studied, and its bearing capacity and failure characteristics were analyzed. The test results show that the prestressed pipe pile PHC500AB(100) meets the standard requirements and has a high safety reserve, but when the pile body cracks, the section stiffness loss is large, and the bending performance is unfavorable.

In order to simplify the calculation process of the reliability of the structural system in seismic design, based on the interlayer displacement, the interlayer displacement is taken as a random variable, and the interlayer deformation failure mode is the main failure mode, and the failure mode correlation of high-rise frame structures under the action of large earthquakes is studied by Monte Carlo method, and the statistical law of partial failure mode correlation of high-rise frame structures under large earthquakes is obtained.

The modification mechanism of polymer cement concrete (PCC) was analyzed by differential thermal analysis, SEM electron microscopy and pore structure tests, and verified by combining indoor macro road performance test and test road drilling test. The results show that with the increase of polymer content, the amount of Ca(OH)2 in cement hydrate decreases, the pore structure is improved, the polymer film tends to be continuous and complete and intertwined with cement hydrate to form a network structure, the internal defects of concrete are reduced, and gradually transformed into a continuous dense structure, accompanied by a large increase in flexibility. The indoor macroscopic test and on-site test also confirmed the following modification mechanism: due to the incorporation of polymer to improve the microstructure of cement concrete, the pavement performance of concrete was significantly improved, and the composite pavement performance was excellent.

The non-Darcy seepage equation considering the initial hydraulic gradient is used to modify the one-dimensional consolidation theory of Terzaghi saturated clay and solved by finite volume method. The calculation results show that as long as the starting hydraulic gradient is greater than 0, the consolidation speed of the foundation is slower than the theoretical value of Terzaghi consolidation, and in addition to the consolidation coefficient, the initial hydraulic gradient, soil thickness and overlying pressure also have significant effects on the consolidation of the foundation. In addition, it is also confirmed that when the main consolidation is completed, there is a certain residual pore water pressure in the foundation that cannot be completely dissipated.

For the welded hollow ball joints, the ANSYS 9.0 program was used to simulate and calculate the bearing capacity, and the elastic-plastic stress and deformation distribution law of the shell surface when the ball nodes were tensile and compressed, and the exact position of the failure zone area in the spherical shell was determined. According to the tensile failure mechanism of welded hollow ball joints, a three-dimensional stress state analysis model of plastic failure failure of ball joints is proposed. Furthermore, the ultimate force analysis under the complex stress state of sphere-weld-steel pipe was studied. The limit state calculation theory is applied to obtain the calculation formula of the tensile bearing capacity of welded hollow ball joints. Based on the discussion of the compression failure mechanism of hollow ball nodes and the statistical analysis of experimental data, the calculation formula of the compressive bearing capacity of ball nodes is obtained by linear regression method with several variable parameters. The data results show that the calculated value of the obtained hollow ball node bearing capacity formula and the experimental value are well fitted.

Through the self-made shear test fixture, under the set shear temperature conditions, the shear strength test was carried out at a certain shear rate, and the shear strength of four different asphalt bonding layers of modified asphalt, modified emulsified asphalt, emulsified asphalt and viscous oil emulsified asphalt were compared, and the influence of three commonly used substrate materials on the shear strength of the bonding layer was compared with the three commonly used substrate materials of cement concrete, cement stabilized crushed stone and lime fly ash stabilized crushed stone, and the results showed that the higher the strength of the substrate material, the better the bonding effect between the layers. Combined with the factors of cost saving and convenient construction, it is recommended to give priority to the use of emulsified asphalt lower sealing layer in expressways.

In order to grasp the local force situation of the Pearl River Bridge, the strain distribution of the box girder concrete near the anchor pad was tested during the longitudinal prestressing construction of block 17# of pier 1#, and the comparative analysis of theoretical calculation and measured value showed that the maximum longitudinal compressive strain obtained by the test was -58.96με, the maximum transverse compressive strain on the side of the anchor pad was -139.37με, and the corresponding compressive stresses were 2.06MPa and 4.88 MPa, respectively, which were much smaller than the compressive design strength of concrete. The anchoring area of the box girder is always in a flexible working state, the longitudinal strain of the box girder roof concrete is compressed, the lateral tension, the measured value is consistent with the law worth the theoretical calculation, except for the closest near the tension jack, the test strain value is in good agreement with the theoretical calculation value, within the range of 52 cm of the anchor pad, the box girder concrete is tensile longitudinally and transversely, and the force is the most unfavorable.

The main influencing factors of surface settlement in urban shallow buried tunnel excavation were analyzed, and a neural network surface settlement prediction model for shallow buried tunnel excavation based on genetic algorithm was established. The finite element numerical simulation forward algorithm is used to obtain the neural network model learning samples and train the model. The prediction model is used in the prediction of surface settlement of light rail tunnel in a city, and the results show that the prediction of surface settlement of tunnel excavation by neural network based on genetic algorithm is feasible, and the prediction results are relatively accurate, which can better guide tunnel construction and ensure the safety of surface buildings.

Aiming at the insufficient compaction performance of the current single-frequency vibration compaction machinery, a dual-frequency vibration compaction machine based on dual-frequency synthesis technology is proposed, and the dynamic model of the machine is established. After experimental research, it is concluded that dual-frequency vibration compaction is better than single-frequency vibration compaction, and that the phase angle selection at (-300,300) has a better effect on deep compaction, and the two-excitation frequency ratio is selected as 3:2, that is, the high frequency is 33.98 Hz and the low frequency is 22.44Hz, the compaction effect is better. And when designing a dual-frequency vibrating roller, the frequency, amplitude, phase angle and other important parameters affecting compaction are given a reasonable choice.

The multi-body dynamic simulation model of C-type vehicle with multiple degrees of freedom was established by ADAMS software, the front suspension system, rear leaf spring system and tire model were analyzed in detail, and a new method for establishing leaf spring multi-body model - neutral plane method was proposed, and the dynamic simulation of the steering stability under different steering wheel angles and changing the position of the center of mass of the whole vehicle was carried out. After comparing with the performance of actual models, the model and analysis results are accurate and reliable, and can be applied to the study of vehicle harshness.

The volumetric efficiency, mechanical efficiency, thermal insulation efficiency and full adiabatic efficiency ηad of high-flow three-lobe roots fan are introduced, and the temperature changes of non-counterflow cooling and counter-flow cooling of the fan are comparatively analyzed. Combined with production examples, the volume efficiency of roots fan changes with the diameter ratio, the thermal adiabatic efficiency of roots fan, the full adiabatic efficiency ηad with the increase of pressure-to-ε ratio of the fan, and the upward trend of exhaust temperature with the increase of pressure ratio ε. The large-flow three-blade roots fan adopts counter-flow cooling to greatly reduce the exhaust temperature and reduce the return impact noise.

The design of hydraulic cylinder receiving and feeding mechanism in automatic production line is introduced, including dynamic modeling, analysis and design calculation of hydraulic system. The flowchart of the FORTRAN software calculation program is given, and the equivalent mass, inertial drag coefficient, efficiency and speed ratio of the transmission mechanism, and the working thrust of the cylinder are calculated. The displacement and velocity changes of the receiving and feeding components are given. The overall design of the mechanical system and hydraulic system of the hydraulic cylinder receiving and feeding mechanism is proposed, and the program analysis results are basically consistent with the test results. The designed hydraulic cylinder type feeding mechanism performs accurate action and smooth movement.

In order to meet the requirements of ultra-fine crushing of new technology, a new type CGM60-B conical pendulum stirring mill was designed, and the working principle and main structural characteristics of the mill were systematically analyzed, and the main technical parameters were given. The product has the periodic deflection movement of the stirring cone, which increases the extrusion, shearing and wear of the medium, and greatly improves the grinding efficiency; Compared with the same volume of stirring mill, it has a large output power; The machine adopts a unique central cooling method, which greatly improves the cooling efficiency.

Under normal physiological pulsation flow, the computational fluid dynamics method and the basic principles of hemodynamics were used to numerically simulate and visualize the blood pulsation flow in the three-dimensional tapering tapered curved artery. The pressure distribution and velocity distribution of blood flow in curved arteries with taper angle at different times in the cardiac cycle were calculated. By studying the blood flow rate and pressure distribution in the lumen of curved arteries and their formation of local stenosis, this paper provides a more reliable theoretical basis for the study of the causes and exclusion methods of atherosclerosis. The results show that the changes of taper angle and curvature of arterial wall have a great influence on the pressure, velocity distribution and local energy loss of blood flow in the pulsating flow under abnormal conditions, which is consistent with the actual situation.

The classification and prediction technology is applied to the mechanical product design database data mining, the product cost prediction model based on the decision tree is established for the key factors affecting the cost of various components, and the rule base of the expert system is adjusted through data mining in combination with the expert system, so that the rules of the expert system can not only come from the summary of expert experience, but also from the mining of previous product data, which broadens the way of knowledge acquisition and improves the efficiency of knowledge acquisition. Finally, a framework of product cost evaluation system based on classification and forecasting technology is given.

The use and application examples of Windows XP SP2 firewall are given. The Windows XP SP2 firewall (ICF) technology was analyzed, and the access, installation, setting and application experiments of personal firewall and ICF were carried out in different networking environments. The results show that the firewall technology of Windows XP SP2 has almost the advantages of other personal firewall technologies, and occupies less system resources, has high prevention functions for network attacks, and enhances the network security of personal computers.

The design method of ARM and CAN interface circuit on a new IED is introduced. When developing a new IED based on ARM microprocessor and uClinux operating system, CAN fieldbus was selected considering the field-level communication requirements of substation automation systems with high reliability and real-time performance. Since the CAN transceiver SJA1000 is an address and data time-sharing multiplexing chip, and the address line and data line of ARM are separated, the software simulation timing method is adopted, and the read and write signal of SJA1000 is generated by using the I/O pin of ARM, the hardware interface circuit of ARM and CAN is designed, the driver of CAN under uClinux is written, and the debugging pass. The design of this interface lays a good software and hardware foundation for the communication of new intelligent IEDs, which can better adapt to the needs of substation automation systems.

Due to the distribution and anonymity of the P2P environment, the traditional access control mechanism cannot provide efficient and secure access control services for the P2P shared file system. Therefore, a new access control framework is proposed based on the trust recommendation mechanism and fair participation mechanism. This framework can realize efficient file access control services without changing the characteristics of the P2P environment itself.

Time synchronization is one of the key technologies of 0FDM system, based on the training sequence structure of IEEE 802.11a standard, a simple correlation time synchronization algorithm is proposed by improving the correlation function and decision conditions. After the improvement of the autocorrelation function, the fluctuation range of the autocorrelation function value is significantly reduced, which provides a possibility for the selection of the best decision threshold. At the same time, by increasing the judgment width, the relevant algorithm can also achieve good results when the frequency offset is large. The simulation results show that when the frame detection probability is 90% and the frequency offset is 200 kHz, the SNR of the proposed algorithm is improved by 8 dB compared with the traditional correlation algorithm.

Blind signatures have great application value in digital cash, electronic voting and other fields, especially the current digital cash, most of which are realized by the principle of blind signature. By improving the DSA digital signature mechanism, a new DSA variant signature algorithm is proposed, and the signature process in the improved algorithm no longer has inverse operation. Then, based on the DSA variant signing mechanism, a safe and efficient blind signature scheme based on DSA variant is proposed.

Combined with the field test of a pumped storage power station, the measured data under power disturbance were used to identify the hydraulic system model of large units with complex water transmission system. The input signal of the identification method is obtained by adjusting the given power of the governor, which does not affect the normal test and operation of the unit. The augmented least squares method was used to calculate the identification, and the identification results were verified by three methods: prior knowledge test, step response test and residual white noise test. The results show that the obtained identification model is credible, and the method of identifying the hydropower system model by using power disturbance is feasible.

A large number of nonlinear loads in the power distribution system are the main cause of harmonics. Combined with the actual situation of power distribution system, the harm of harmonics is analyzed, and some commonly used harmonic control measures are given for different types of harmonic sources. These include reducing the amount of harmonics generated by nonlinear loads and setting AC filters, etc., and briefly explain the problems that should be paid attention to in the use of various measures.

The apparent kinetics of the reaction of the new process of synthesizing stannous methanesulfonate with methanesulfonic acid and metal tin grains were studied. The change rate of methanesulfonic acid concentration with time was investigated, and the experimental data were processed by least squares method combined with Arrhenius’ formula, and the reaction kinetic velocity constant and apparent activation energy of the reaction were obtained at different temperatures. The results show that the chemical reaction between methanesulfonic acid and metallic tin to form stannous methanesulfonate is a liquid-solid surface reaction, which belongs to the zero-order reaction. In the range of 393.15~423.15 K, the apparent activation energy of the reaction was 27.02 kJ·mol-1.

The properties of the error ellipsoids and the representation of spatial point errors were studied. Using probability theory and multivariate analysis as tools, it is proved that the probability of the spatial point error falling into the ellipsoid can be represented by the distribution function and density function of the standard normal distribution. It is proved that the spatial point error can be decomposed into three independent components along the direction of the error ellipsoid main axis, and the decomposition method and example are given. The probability of proving that the point error falls within one side of the error ellipsoid is a constant, which is independent of the tangent point coordinates and can be represented by the standard normal distribution function; The visual expression of point error is discussed, ellipsoid and cuboid confidence domains are established for spatial points, and the calculation formula of confidence level is given.

Ethyl orthosilicate (TEOS) is used as the main raw material, ethanol as solvent, hydrochloric acid or ammonia as catalyst to prepare silicate gel. The mechanism of sol-gel reaction and the effects of catalyst, water, solvent and reaction temperature on gelling time, viscosity and structure of gel were discussed. The two-step Sol-Gel method of first acidic and then alkaline can greatly shorten the gelling time.

GSM/GPRS is a kind of data carrying and transmission mode based on packet switching technology, which has the characteristics of real-time online, fast login, high-speed transmission, and free switching, which is very suitable for remote fire alarm. The system composition and working principle of a remote fire alarm based on GSM/GPRS network are designed, and the software and hardware design and functional implementation of the system are given. The practical application shows that this remote fire alarm based on modern communication and network transmission technology can shorten the fire alarm time, effectively play the role of fire fighting facilities, quickly extinguish the fire, and provide a practical networking technology scheme for fire remote alarm.

Using self-designed high-frequency transmitter (10~20MHz), the ring antenna and line antenna were excitation experiments. The results show that when the direct coupling loop antenna is greater than 10 W, the gas in the antenna can be excited to form plasma, and the plasma can still be maintained when the RF power drops to 5 W. For line antennas, plasma can be excited when the RF power reaches 20W when directly coupled; When the RF power reaches 30 W during capacitive coupling, plasma can be excited to be generated, and when the RF power drops to 10 W, both coupling methods can maintain plasma. Using the ring metal antenna as the receiving antenna, the emission performance of ring and linear plasma antennas in direct coupling mode and capacitive coupling mode was measured, and the results showed that the plasma antenna had the same radiation performance as ordinary metal antenna, and the received signal level increased with the increase of the transmitted signal level, showing an approximate linear relationship. Therefore, plasma antennas can be used for high-frequency radio communications.