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Abstract: A high-order non-singular terminal sliding mode control strategy is proposed to address the issue of achieving maximum wind energy capture in permanent magnet direct drive wind power generation systems. Based on the nonlinear model of the permanent magnet direct drive wind power generation system, a maximum power point tracking method based on optimal torque tracking is proposed, Applying high-order non-singular terminal sliding mode control to the design of torque controller and current controller for permanent magnet synchronous generator (PMSG), achieving fast tracking and stable control of the maximum power point of the permanent magnet direct drive wind power generation system without wind speed sensors. Simulation results verify the effectiveness of the proposed control scheme

Abstract: In response to the strong vibration conditions of a tunnel boring machine (TBM), two mechanisms causing fatigue failure of the pump shaft were analyzed: changes in load and material properties. A force simulation model of the pump shaft under strong vibration was established, and the steady-state force amplitude of the pump shaft increased linearly with frequency and vibration amplitude. Based on empirical data, S-N curve correction models were obtained under different working conditions. A finite element model of the pump shaft was established, Load different working conditions and material parameters to obtain the law of vibration parameters affecting the fatigue life of the pump shaft. The results show that when the amplitude is less than 3 mm and the frequency is less than 20 Hz, the pump shaft can always meet the life requirements; When the amplitude is greater than 4.8 mm, it cannot meet its service life requirements; When the frequency is 10 Hz, the maximum amplitude that can meet the fatigue life of the pump shaft is 4.3 mm

Abstract: A single-phase and three-phase combined transformer power supply system applied to electrified railways was studied. The structure and working principle of the single three-phase combined power supply system, as well as capacity utilization and negative sequence characteristics, were analyzed. The transformer of the single three-phase combined power supply system was first simulated using Matlab/Simulink, and the simulation results showed that the structure and principle of the single three-phase combined power supply system were in line with theoretical analysis. Secondly, Simulation verification was conducted on the same phase power supply system composed of combined transformers, and the simulation results showed that the compensation scheme was effective

Abstract: In response to the current construction status of specialized transmission projects, optimization methods are adopted to select the main electrical equipment of the transmission project, such as high-voltage circuit breakers, transmission lines, transformers, etc. An optimization model is established that considers one-time investment, annual operation and maintenance costs, and power outage losses. The optimization model is used to select the most cost-effective investment plan from a large number of electrical equipment that meet the technical parameter requirements. This plan takes into account both economy and reliability, To minimize the annual comprehensive operating cost, an ant colony algorithm was used to solve the problem. In response to the slow optimization speed of the algorithm, an improved neighborhood ant "benchmark" learning algorithm was used for optimization. Finally, the effectiveness of the model and algorithm was demonstrated through calculation and analysis of a residential dedicated transmission project example

Abstract: Experiments and actual operation experience show that the impact characteristics of grounding devices are an important factor affecting the lightning performance of transmission lines. Based on the dynamic and distributed soil parameters in the process of soil ionization, the author establishes a finite element model of impact characteristics for typical grounding devices; according to the simulation The calculation results and simulated test results analyzed the impact flow mechanism and flow law of typical grounding devices from the perspective of electromagnetic field; at the same time, the impact law of soil parameters and injection current parameters on the volume of soil ionization area under the action of impact current was quantitatively calculated. The impact of soil ionization on grounding parameters such as grounding resistance, step voltage, and contact voltage of typical grounding devices is analyzed above. The results show that the impact of soil ionization on the characteristics of shock dispersion and shock grounding The area is more obvious. The research results can provide theoretical support for the proposal of new measures to reduce the resistance of transmission line impact grounding.

Abstract: The synthesis of ε-caprolactone from cyclohexanone was catalyzed by Fe-Sn-O composite oxides prepared by coprecipitation in molecular oxygen-benzaldehyde system, the optimum synthesis conditions were obtained as follows: 5 mmol cyclohexanone at room temperature and atmospheric pressure, N (benzaldehyde)∶ N (cyclohexanone) = 3∶1, Ethylene Dichloride 20 mL, oxygen flow rate 20 mL/min, reaction time 4 h; Reaction temperature 55 °C. Under this condition, the yield and selectivity of ε-caprolactone were 98.8% and 99.0% , respectively, and the structure of the catalyst was characterized by SEM and XRD.

Abstract: Using Al2 (SO4) 3 as a solid acid catalyst, the process of catalyzing cellulose to produce ethyl levulinate in the ethanol/toluene system was investigated. The effects of the volume fraction of co solvent toluene, reaction temperature, catalyst dosage, and reaction time on the yield of ethyl levulinate were investigated. The catalytic effect of the catalyst on different carbohydrates and its reusability were also investigated. The results showed that at a toluene volume fraction of 10% and a reaction temperature of 180 ℃, When the catalyst dosage is 0.8g and the reaction time is 3 hours, the molar yield of cellulose alcoholysis to ethyl levulinate is as high as 51.6%; The molar yields of fructose, glucose, sucrose, and inulin to produce ethyl levulinate are 54.3l%, 47.3%, 51.4%, and 49.6%, respectively. Al2 (SO4) 3 has good universal applicability for the alcoholysis of carbohydrates to produce ethyl levulinate. The catalyst still exhibits good catalytic activity after being recycled and reused for 5 times

Abstract: Polyamide dendrimers of generation 0.5-4.0 were synthesized by Michael addition and amidation condensation reactions with ethylenediamine as the nucleus, and their structures were characterized by nuclear magnetic resonance (NMR) and infrared spectroscopy (FI-IR). As a sensitive material combined with a QCM (quartz crystal microbalance) transducer to construct a resonant formaldehyde sensor. Studies have shown that due to the rich amino functional groups on the surface of the dendrimer, it has a good specific response to formaldehyde, and its high viscosity, It also makes it possible to stably form a film on the surface of the QCM. After repeated measurements, the sensor has a high degree of repeat stability.

Abstract: Using dolomite, magnesite, silica and zircon as raw materials, a stable zircon magnesite dolomite composite with CaO content of 35%, C/S ratio (CaO/SiO2 molecular ratio) of 2.5, and ZrO2 content of 2%, 4%, 6%, and 8% was prepared by two-step calcination and digestion process, The microstructure of the material was analyzed using SEM. The results showed that at 1000 ℃, zircon decomposed into CaZrO3, and calcium silicate began to form at 100 ℃. After 1300 ℃, CaO completely reacted; As the firing temperature increases, the density of the material increases, and the bulk density of the material increases to 3.113.16g/cm3 after firing at 1600 ℃; After firing at 650 ℃, the hydration weight gain of the material was 0.03% 0.07%, and f-CaO transformed into stable calcium silicate and CaZrO3 phases, significantly improving the material’s hydration resistance

Abstract: The black organic ink powder obtained from the waste toner drum after being treated by the waste toner drum crushing magnetic separation device is used as the raw material. The surface organic matter is removed by environmentally friendly low boiling point organic solvent treatment, and a brown magnetic iron oxide material can be obtained by calcination at 500 ℃. XRD measurement shows that the iron oxide obtained by this method is γ- Fe2O3; Scanning electron microscopy (SEM) shows that its morphology is uniform and circular, with an average particle size of around 200 nm. The gas sensing performance test results show that compared with commercial Fe2O3, this γ- Fe2O3 material has good gas sensitivity and selectivity to VOCs (ethanol, acetone, etc.) gases, and is expected to be applied in the detection of volatile organic compounds

Abstract: The reduced graphite oxide/titanium oxide (rGO-TiO2) nanocomposite sensitive material was prepared by hydrothermal method using titanium tetraisopropoxide and graphite oxide (GO); Compared with a single rGO, composite sensitive materials exhibit higher response (rGO TiO2 vs. 10 × The response of 10-6NH3 is -0.027, with rGO of -0.007, and better repeatability. In addition, the gas sensitivity mechanism of the composite material to NH3 was analyzed

Abstract: The multiple reflection cavity is the core component of the laser absorption spectrum gas sensor, and its structure and performance directly affect the sensitivity and stability of the entire equipment. The design scheme and working principle of multiple reflection cavities mainly used domestically and internationally, such as White cavity, Herriott cavity, CEAS cavity, were analyzed. 96 reflection cavities were designed and manufactured, and applied to the vehicle laser methane inspection instrument. The practical application of the gas company showed that:, This equipment greatly improves the efficiency of gas inspection, shortens the cycle of gas inspection, and effectively reduces the occurrence of deflagration accidents

Abstract: In view of the problem that the risk that exists in land requisition and resettlement of the south tonorth water diversion middle route project is so much and changes with the implementation progress,This pa-per taking Tidal River section as an example,on the basis of analyzing work characteristics and risk origin,i-dentifies risks fully dynamically through building WBS-RBS matrix and calculates the weight and degree ofrisks based on AHP and risk degree theory. Finally,it makes comprehensive evaluation according to the level5 risk criteria.The result shows that the overall risk is level 3 medium with the greatest risk ranking level 4 inresettlement phase,which is basically consistent with the engineering investigation result and should be spe-cially focused on.

Abstract: In order to investigate the influence of dry wet cycling on the mechanical properties of cement modified expansive soil, direct shear tests were conducted on the expansive soil of the Taihu Road station foundation pit of Hefei Metro Line 1 with different cement mixing ratios and curing ages. The optimal cement mixing ratio and curing age were determined. Based on this, We conducted expansion and contraction deformation tests and direct shear tests on expansive soil and cement modified expansive soil under dry wet cycling conditions. The test results showed that the expansion and contraction deformation process of expansive soil is not completely reversible. With the increase of dry wet cycling times, the shear strength gradually decreases, the absolute expansion and contraction rate gradually increases, and ultimately tends to stabilize; After cement modification, the shear strength and water stability of expansive soil are significantly improved, while the expansion and contraction properties are significantly weakened; After cement modification, the influence of dry wet cycling on expansive soil is significantly reduced

Abstract: In order to study the performance of direct coal liquefaction residue (DCLR) modified asphalt mixtures, 10% DCLR (mass ratio to base asphalt) modified asphalt mixtures and composite DCLR (2% SBS+15% rubber powder+10% DCLR) asphalt mixtures were prepared, and their performance was compared with hot mix asphalt mixtures and SBS modified asphalt mixtures. The experimental results showed that the addition of DCLR can improve the high-temperature stability and water stability of asphalt mixtures, But there is damage to its low-temperature performance; The low-temperature performance of composite DCLR asphalt mixture has been greatly improved, and its high and low temperature performance and water stability are significantly higher than those of SBS modified asphalt mixture

Abstract: A finite element analysis model for the spatial vibration of a train, cable-stayed bridge, and T-shaped rigid frame collaborative system was established. The coupled motion equations of the vehicle bridge system were established based on the assumption of wheel rail close contact. The German low interference spectrum was used to generate track irregularity samples as excitation sources, and a (100+2) × The natural vibration characteristics of a 210+100) m cable-stayed bridge and a T-shaped rigid frame collaborative system, as well as the spatial vibration response of four train models passing through the bridge at different speeds, were calculated and analyzed. The results show that when calculating the natural vibration frequency of the bridge, the first and second natural frequencies are both the main beam transverse bending; The collaborative system of cable-stayed bridges and T-shaped rigid frames can improve the vertical stiffness of the entire bridge; When the German ICE3 model passes through a bridge, the vibration response of the vehicle bridge system is the highest, with a vertical deflection to span ratio of about 1/5 440. All indicators of the vehicles on the bridge are within the allowable values specified in Chinese regulations; The horizontal and vertical ride comfort indicators of the vehicle passengers both meet the "good" standard, indicating that the cable-stayed bridge and T-shaped rigid frame cooperation system can better meet the requirements of high-speed driving.

Abstract: In order to study the repair and reinforcement effect of high-performance grouting materials in the hinge joints of hollow slab bridges, a full-scale test of high-performance grouting materials for repairing the hinge joints of hollow slab bridges was carried out by taking three 30-meter-span hollow slab girders removed from the real bridge as objects. Research. Through the concentrated loading of the mid-span mid-span of the prefabricated hollow slab bridge composed of three hollow slabs after hinge joint repair, the load-deflection curves of each slab girder were measured and analyzed, and the failure mode of the test was given. Test results It shows that the deflection changes of each plate girder are basically the same at the initial stage of loading, and the overall performance of each plate girder is good; the failure form in the limit state is the longitudinal brittle cracking failure of the joint surface between the grouting material and the plate girder; The overload reserve for the design load is 1.74.

Abstract: In order to identify the damage location of aluminum beam structures, piezoelectric impedance technology was used to conduct damage localization experiments on aluminum beams. Precision impedance analyzers were used to measure the impedance real part signals of non-destructive and self-made damage holes at different frequency bands, and Pearson correlation coefficients were used to process the experimental data, Through multiple experiments, the impedance real part correlation coefficient values were found to be approximately linearly related to the distance between the piezoelectric ceramic sensor (PZT) and the damage in the applicable frequency range. Aluminum beam damage localization experiments were conducted within the applicable frequency range, and the detection values of damage holes and crack positions were basically consistent with the actual values. This confirms the effectiveness of this method in aluminum beam damage localization and can provide reference for non-destructive testing of damage localization

Abstract: The electroplating power supply has the characteristics of low voltage and high current operation, and the traditional voltage control mode is difficult to meet the control requirements due to defects such as slow dynamic response and inability to dynamically limit current. After comparative analysis, a dual loop controller control scheme using a voltage outer loop and a current inner loop is proposed. The electroplating power supply system is modeled and analyzed, Design a dual loop controller in the order of starting with the current inner loop and then the voltage outer loop. Use the Bode diagram to analyze the loop stability of the system model, design the loop parameters, and modify the current loop parameters based on the conditional stability phenomenon that occurs during the operation of the dual loop system. The experimental results show that the dual loop control system operates normally and has practical value

Abstract: The traditional edge preserving filtering based single image fast defogging algorithm, under the influence of atmospheric particle scattering caused by haze pollution, the image will be affected by the fog background, resulting in dense fog noise and poor image structure information restoration. A weighted filtering image fast defogging algorithm based on chaos is proposed, which obtains the chaotic characteristics of the image data by analyzing the image information under the fog background interference, And the minimum color component estimation is performed on the atomized image. Based on this, a self adaptive weighted filtering model is constructed by combining the dark primary color model of the fogged image, the time-domain and frequency-domain feature component models, and an improved design of a chaotic weighted filtering image fast defogging algorithm is completed. The experimental results show that using this algorithm can avoid color distortion in the middle area of the atomized image, reduce atomization background interference, and reduce dense fog noise, Reasonably preserving the chaotic features of the distant view has advantages in image quality and computational performance

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