Through a meso-model, the nonlinearity and strain softening of the stress-strain relationship of concrete under compressive stress are explained from the perspective of damage, and the elastoplastic damage constitutive model of uniaxial compression concrete is established according to the isometric hypothesis and the basic principle of damage mechanics, which can derive the existing uniaxial compression constitutive relationship and reflect the stiffness degradation of concrete and the residual deformation after unloading. A class of damage function and plastic deformation empirical expression are proposed, and the stress-strain curve feature conditions and optimization algorithm are used to determine the model parameters. Compared with the results of the existing compression test, the results are in good agreement.

Through the drawing test study of the bearing capacity of cement-based inorganic bonding materials, the failure form and failure mechanism of cement-based inorganic bonding materials are analyzed, and the calculation formula of ultimate anchorage bearing capacity and the table of recommended anchorage length are discussed and given. The engineering applicability of this cement-based inorganic bonding material was obtained by comparing with the embedded steel bar, post-binding welding of the planting bar and the bearing capacity of the planting bar of an organic binder under the same conditions, and it was verified in the actual engineering.

A reinforcement method for anchor steel plate is proposed, and the force characteristics and reinforcement effect of the reinforced steel plate reinforced beam are analyzed by the bending performance test of two reinforced concrete beams reinforced by anchor steel plate (one beam reinforced by pasted steel plate and one control beam), and compared with the pasted steel plate reinforcement beam and the control beam. The experimental results show that compared with pasted steel plate reinforcement, anchor steel plate reinforcement has the advantages of simple construction process, good reinforcement effect, and easy assurance of reinforcement quality, and is a new reinforcement technology with wide engineering application prospects.

Using the finite element analysis software, the advanced analysis of a herringbone transformer architecture is realized, and the process of advanced analysis is discussed. Through the analysis and comparison of the calculation results of advanced analysis and traditional first-order elastic analysis, the defects in traditional first-order elasticity calculation and the influence of several main factors in the advanced analysis of herringbone power architecture are preliminarily discussed. The calculation results show that the geometric nonlinearity has a great influence on the herringbone structure. When selecting member elements with advanced analysis, fully consider member elements with large axial forces; The influence of the second-order effect on the internal force gradually decreases from the bottom up.

The surface of old concrete after rough treatment has fractal characteristics. Through the self-made roughness tester, the surface roughness of old concrete was evaluated by simple fractal method, and compared with conventional test methods. The data show that the fractal dimension and average sand filling depth have good linearity, which can be used as the roughness evaluation index of concrete. The measuring instrument is simple to operate and easy to use, which is suitable for measuring the surface roughness of old concrete in actual reinforcement projects.

Under plane strain conditions, the expression forms of Matsuoka Moto-Nakai Teruo failure criterion, Lade-Duncan failure criterion and Yu Maohong double shear unified strength criterion were derived, and the soil shear strength index under plane strain condition and conventional triaxial compression condition was linked. On this basis, the active earth pressure calculation formula considering the influence of intermediate principal stress is obtained. The calculation shows that as long as the internal friction angle of the filled soil is greater than 0, the active earth pressure value considering the influence of the intermediate principal stress is smaller than the Rankine active earth pressure value, but the calculation results differ greatly depending on the failure criteria.

Aiming at the parallel design problem of building structure and control system under random excitation with structural parameters as variables and minimizing control input force as the optimization goal, a parallel optimization algorithm based on linear matrix inequality tool is designed. The algorithm breaks through the limitations of existing algorithms in the following two aspects: the quality matrix is included in the optimization variable, which broadens the optimization scope; The convex potential energy function processing is used to introduce control into the non-convex constraint caused by structural design, which greatly reduces the complexity of the algorithm. The analysis results show that the algorithm can effectively improve the efficiency of structural design.

In addition to elastic strain, the measured strain of concrete also includes non-stress strains such as free deformation, creep and temperature strain of concrete, and the methods and steps of indirect stress measurement in continuous rigid bridges of prestressed concrete are introduced. In the conversion of measured strain and stress in concrete, the non-stress gauge is used to remove the non-stress strain, the strain gauge embedded in the neutral axis of the main beam is used to identify the creep coefficient of concrete, and the creep strain is separated by the superposition method. The key to the internal stress measurement of concrete lies in the stress-strain conversion, and the key to stress-strain conversion lies in the identification of the creep coefficient. During the construction monitoring of Xijiang Bridge, the neutral axial stress was used to identify the creep coefficient, and then the creep-strain separation method was carried out, and the measured value of stress was close to the calculated value of elastic theory.

The on-site static load test was carried out on the manually dug hole and bottom-expanding long piles placed in the loess layer and supported in the silty clay layer, and the pile top settlement S and pile bottom settlement Sb under each stage of load were measured, and the vertical bearing characteristics of the extended bottom long piles were analyzed. It is pointed out that the stress mechanism of the extended long pile is obviously different from the short pile with the bottom expansion, and the bearing characteristics of the extended long pile placed in the loess layer are basically the same, and its ultimate bearing capacity is mainly based on side resistance, which has the characteristics of significant end-bearing friction pile. In addition, the experimental data show that water immersion will have a great influence on the pile side friction resistance of collapsible loess.

Carbon fiber cementitious materials with volume content (0.0%, 0.2%, 0.4%, 0.8% and 1.2%) were fabricated, and the test pieces were 100 mm× 100 mm × 100 mm cubes. The conductivity performance was compared, and the relationship between compressive stress and resistivity of concrete with different carbon fiber content under monotonic and cyclic loads was experimentally studied. The results show that with the increase of carbon fiber content, the impedance curve gradually shifts to the left, and the fibers randomly distributed in three-dimensional space gradually aggregate and connect with each other, which greatly increases the conductivity of the composite. When the volume content of carbon fiber is the same as 1.0%, the AC impedance spectrum of materials of different ages varies greatly, and with the increase of hydration age, a large number of C-S-H gels are formed, and the solution resistance in cement-based materials gradually increases.

Based on Bio seepage consolidation theory, isotropic linear elastic damage theory and fatigue damage theory, a mechanical analysis model of water damage of asphalt pavement is proposed, the axisymmetric finite element method is used to solve the mechanical model, and a finite element program is prepared for numerical simulation analysis. The influence of pore water pressure on the stress state of asphalt pavement and the fatigue damage process of asphalt pavement under the action of vehicle in the presence of pore water were analyzed. The calculation results show that the pore water pressure in the asphalt surface layer is closely related to the permeability coefficient, surface thickness and vehicle driving speed of the surface layer. When the pores of the road surface are saturated with water, under the load, the presence of pore water will lead to the intensification of the stress concentration of the pavement structure, and under the repeated action of the load, it will lead to fatigue cracking and failure, and accelerate the emergence of road surface diseases.

In order to analyze the base stress of the new pavement structure of asphalt pavement of poor concrete base layer, the load stress of poor concrete base layer is calculated by finite element analysis method, and the influence of asphalt surface thickness on it is analyzed by elastic layer theory, and the calculation formula of base load stress is derived. According to the temperature field and maximum temperature gradient of different natural divisions, the finite element solution of the temperature stress of the base layer in the asphalt pavement of the poor concrete base layer is obtained, and the calculation formula of the base temperature stress is proposed. The above two formulas are important bases for the design of base layer thickness in asphalt pavement structure of poor concrete base layer.

In the DS-CDMA system, the formation of the smart antenna pattern must rely on the estimation of the arrival direction of the mobile station. In order to accurately estimate the incoming wave direction, the traditional algorithms for DOA estimation of DS-CDMA systems: MUSIC algorithm and ESPRIT algorithm are analyzed and studied. These two algorithms are based on subspace decomposition, which is computationally intensive and not easy to implement in real time. Two improved algorithms based on MUSIC algorithm and ESPRIT algorithm are proposed for DOA estimation, which greatly reduces the amount of computation. Simulation experiments show that the two improved algorithms are easy to implement in real time in the multipath signal environment of CDMA system.

In view of the TCP/IP protocol used in most PC cluster systems, this paper focuses on the implementation of socket communication mechanism as a distributed interprocess communication means in Linux and the main factors affecting performance in traditional communication overhead, and improves the traditional communication protocol stack for communication bottlenecks, and proposes a method to improve the performance of cluster networks for the shortcomings of WAN protocols in PC cluster systems.

The circuit topology and control strategy of one of the most commonly used and advanced active power factor correction techniques are discussed, the average current control principle in the control strategy is analyzed in detail, and the research results of the power factor correction circuit for 50 V/20 A communication power supply are given. The power factor reaches less than 0.99, which is suitable for high-power applications.

In order to further improve the input-output dynamic decoupling control problem of MIMO system, this paper comprehensively uses state feedback, input transformation and coordinate transformation methods to obtain a concise and complete decoupling normative type, and gives the feedback control law of configuring the characteristic structure of each subsystem and the display expression of each feedback matrix.

In the design of parallel fuzzy PID composite controller, the ratio of fuzzy control part and PID control part must be adjusted in time according to the deviation, and this more complex control strategy is difficult to achieve by using ordinary Simulink module. The S-function is used to solve this problem, and the S-function is first written based on the MATLAB language to realize the adjustment of fuzzy control and PID control ratio, and then the S-function program is called in the Simulink simulation environment to establish the simulation model of fuzzy PID composite control system. The simulation model of this method is simple and easy to program, and it is convenient to adjust the proportion of each part in the parallel structure with the size of the deviation, so as to achieve better control effect.

Taking Ce(NO3)3*6H2O and (NH4)2 CO3*H2O as raw materials, and adding a small amount of PEG600 as a dispersant, Ce2 (CO3)3*8H2O precursor was synthesized by rapid chemical precipitation, and after heat treatment, nano-CeO2 was obtained, XRD, DTA, TEM, BET and spectral analysis and characterization were carried out on the sample, and the CeO2 grain size was calculated by Gaussian algorithm according to slow scanning. The results showed that the precursor completely turned into CeO300 after roasting at 2°C, the particle size was about 10~20 nm, the grain size was 5.7 nm, the specific surface area was 111.68 m2/g, and the purity was >99.97%.

The rotor system of large turbine compressor units is gear-coupled shafting, and torsional vibration analysis is commonly used in engineering to carry out torsional vibration analysis on such units. These two methods are compared and analyzed with the bending and torsion coupling calculation method through numerical calculation, and the results show that the folding or torsional coupling algorithms widely used in engineering cannot fully reflect the torsional dynamic characteristics of this type of unit, and there are defects. In order to avoid all harmful torsional vibration of the unit, the influence of the transverse vibration of the rotor of the unit on the torsional vibration must be considered when the torsional vibration analysis of the unit is carried out, and the bending and torsional coupling vibration theory is applied for system analysis.

The cargo holding mechanism is the key mechanism of the hoist, if the goods are required to be lifted at high speed and high position accuracy, the cargo holding mechanism must be flexible to achieve a soft combination with the goods and buffer the impact force when the goods are lifted into place. The elastic vertical cargo mechanism (disc spring type) was adopted to carry out design calculation and structural design of the mechanism, and the impact check was carried out for the special fault of the hoist. The results show that the agency has passed a full range of experiments and is being applied to military products.

The formula was gradually and regularly changed to synthesize polyacrylic acid copolymers of different compositions, and its emulsification stability ability for polymeric monomers butyl acrylate and styrene was investigated, and a suitable polymer emulsifier formula was obtained. The emulsion polymerization reaction of butyl acrylate-styrene and butyl acrylate-styrene-epoxy resin was carried out by using synthetic polyacrylic acid as a polymer emulsifier, and the influence of multiple factors on the conversion rate of monomers was investigated by using 11-factor 2-position orthogonal experimental design without interaction influence, and it was found that the molecular structure of the synthetic emulsifier, the amount of neutralizing amines and the amount of initiators had great effects on the conversion rate. Combined with the needs of practical application, the 3-factor 5-position quadratic regression orthogonal experimental design with interaction influence was used to investigate the effects of initiator dosage, emulsifier dosage and epoxy resin dosage on the final conversion rate of monomers

A series of NaA-type zeolite membranes were synthesized on the outer surface of tubular α-Al2O3 ceramic tubes by in-situ hydrothermal secondary synthesis and microwave closed synthesis methods, and the effects of four raw material ratios and four crystallization methods on the synthesis of zeolite membranes were investigated, and the synthesis conditions were optimized. The synthesized membranes were characterized by pervaporation experiments of XRD, SEM, and ethanol aqueous solutions (purging the permeable side with nitrogen as osmotic thrust). The results showed that when the ratio of raw materials was Na2O∶Al2O3∶SiO2∶H2O=1∶1:3.6∶100, the molecular sieve membrane synthesized by the clear liquid coating crystal seed and microwave sealing had good selectivity for water and ethanol, and the separation factor was much greater than that of the blank tube, and 95% (wt) of ethanol aqueous solution passed through the membrane

Bisphenolic acid was synthesized by condensation reaction using hydrochloric acid as catalyst, thioglycolic acid as cocatalyst, and levulinic acid and phenol as raw materials. The molar ratio of levulinic acid to phenol, the molar ratio of levulinic acid to hydrochloric acid, reaction temperature and time were selected as follows: reaction temperature 9 °C, reaction time 34 h, n(levulinic acid)∶n(phenol)=60∶45, n(levulinic acid)∶n(hydrochloric acid)=1∶4, n(levulinic acid)∶n(hydrochloric acid)=1∶4, and the yield of bisphenolic acid reached 97.1%.

Using ammonium sulfate, a by-product of electrosynthesis of p-aminophenol, as raw material, in a self-made box-type electrochemical reactor, titanium-based platinum-plated electrode is used as the anode, lead-antimony alloy electrode is used as the cathode, and Nafion 427 cation exchange membrane is used as the diaphragm to prepare ammonium persulfate. Taking current efficiency and yield as the optimization goals, the influence of various factors on the electrolysis reaction was investigated. The optimized conditions were as follows: the content of p-aminophenol in the by-product ammonium sulfate was less than 0.05%, the initial concentration was 36.5%, the anode additive was 0.06% ammonium polyphosphate, the electrolysis temperature was 15 °C, the current density was 10 000 A*m-2, and the electricity was 72.48 A*h. Under these optimal conditions, 5 batches of repeated electrolysis experiments were carried out, and the current efficiency was higher than 80% and the yield was higher than 55%

In order to study the microbial indicator characteristics during activated sludge culture and operation, according to the physiological characteristics of microorganisms, SBR process was adopted, fresh domestic sewage was used as nutrient solution for direct aeration, and activated sludge was gradually cultivated by controlling pH, temperature, dissolved oxygen and other conditions.

The environmental behavior and purification mechanism of river water containing nitrate nitrogen pollution in the infiltration system of Weihe River were simulated and studied by self-designed indoor soil column experimental device, and the environmental behavior was mainly denitrification. It is concluded that the river percolation system has a great purification effect on nitrate nitrogen sewage, and its purification degree is related to the percolation medium of the percolation system, if the percolation medium is a fine-grained clay layer, the purification degree of nitrate nitrogen sewage is very high, and the purification rate reaches 100%, but it is easy to cause negative effects such as increased groundwater hardness. If the medium is coarse sand substance, its purification degree is low, but it is not easy to cause the hardness of groundwater to increase.

The alkylation reaction between chlorinated polypropylene and toluene catalyzed by aluminum chloride (AlCl3) was studied. The infrared spectra showed that an aromatic ring group was attached to the original CPP molecular chain. A series of kinetic data were determined, the kinetic parameters were determined by data fitting, the reaction kinetic model was obtained, and the reliability of the kinetic equation was verified. The compatibility of the modified chlorinated polypropylene with 200# gasoline was improved.

The uniform experimental method was used to optimize the process conditions for extracting phenanthrene from rice bran by microwave-assisted method. The experimental results show that the microwave-assisted extraction method has significantly improved product quality and yield compared with the traditional extraction method, and the extraction time is shorter. The optimal process conditions were as follows: water addition 3 mL, microwave power 100 W, microwave radiation time 1 min, leaching time 5 min, decolorization microwave power 100 W, decolorization time 41 min, solvent v(HCl)∶v(H2O)=3∶197.Under the optimal process conditions, the phenanthine content reached 86.13% and the extraction rate reached 91.87%.