Advanced Materials Research Vols. 468-471

Abstract: Robust recursive updating model is insensitive to the outliers in observed flow data and is effective to obtaining stable flood updating accuracy. At the same time, it is risky to detect falsely good value as outliers. Using Monte-Carlo method, the relations between risk and effect of model are got. The study results indicate the risk of the model is impacted by frequency of outliers.

Abstract: The problem about the eddy current loss which is caused by leakage magnetic field in ultrahigh pressure large capacity power transformer is becoming more extrusive. It is very significant to research the power transformer leakage magnetic field and eddy current loss on the tank wall thoroughly and accurately. 3D finite element model of power transformer leakage magnetic field and eddy current loss is established in this paper, the eddy current loss on the tank wall is calculated and the distribution is analyzed. For the eddy current loss could be reduced by magnetic shielding, new calculation model are established respectively, then eddy current loss on tank wall could be got with shielding. The best size and location of the shielding could be analyzed after changing the height of the shielding, which provided the important evidence to reduce tank wall eddy current loss effectively. The calculating methods have been proved to be accuracy after experiment.

Abstract: In this thesis, based on the weft organization features parameters analysis results, according to warp yarn arrangement features , apply correlation coefficient and autocorrelation function in weft weave texture feature recognition, establish weft cell image, analysis the weft cell image correlation coefficient, find out the number of weft circle, set up same kind weft cell image of the same phase of weft unit, calculate the warp brightness values of the same kind weft cell image, distinguish the weft points area and warp points area through luminance signal analysis, analyze the tissue points area changes between the adjacent similar weft cell, and determine the location and density of warp yarn. Experiments prove that the Fourier-transform method is feasible and has considerable accuracy.

Abstract: To make the structure of aircraft meet the aerodynamic requirements, complex lightweight structures such as double curvature shape and high-strength lightweight materials such as titanium alloy are generally used in design and forming of aircraft skin parts. But the forming processes and problems aimed to this kind of parts remain to be investigated further now. In this paper, based on single point incremental forming process, the TC4 titanium alloy aircraft parts with a complex double curvature was studied. In order to reduce the springback during the forming process an appropriate addendum surface was added to the part surface, and then ABAQUS software was applied to carry out numerical simulation of the forming and springback process. The results show that springback of complex titanium part with double curvature is small at both ends of part while large in the middle and the distribution of springback orientation depends on the curvature. For that the part is difficult to form by single point incremental forming process without springback compensation, so the tool path needs to be improved firstly. The simulation results can play a role for guiding the parameters selection and the compensated surface design of single point incremental forming process which can achieve the cold forming of parts with complex structure for poor formability materials.

Abstract: A sealed air cooling local environment control apparatus that can provide constant working environment for precision instruments has been developed. Based on electrical analogy, the thermal network model has been derived, and the parameters of thermal conductance and capacitance in the model were measured in different test conditions. The obtained maximum relative errors between the measured values and the theoretical values are in the range of 0.6% to 6%, which indicates that the proposed theoretical model and the test method are feasible. The obtained parametes can help to understand the heat transfer properties of the apparatus, and the methods can be also as the reference for the test and rapid commissioning of other local environment control apparatus.

Abstract: Adopting raman spectrometer to conduct qualitative and quantitative analysis of m-cresol and p-cresol, selecting the respective character peak of bencycloquidium after deformation vibration (m-cresol at 732 cm-1 and p-cresol at 841 cm-1), via experiment and calculations, the relative raman cross section of m-cresol and p-cresol can be concluded:(∂σ/∂Ω)_732cm^-1/(∂σ/∂Ω)_1000cm^-1 is 0.74 (height-fitting of the peak), and 0.61 (area-fitting of the peak). This method samples simply and rapidly, and has a short testing time, whose quantitative analysis result of m-/p-cresol is consistent with that of GC analysis.

Abstract: An intelligent system, which is real-time, remote, and automatic for monitoring the settlement of surface subsidence or building, was developed based on the principle of communicating vessels. The Hydrostatic leveling, displacement sensors, data acquisition and transmission, 3G wireless communications module, computer terminals, and data processing software were integrated in the system, which has the following functions: monitoring data real-time acquisition and transmission, automatic calculation and analysis of the settlement, and early warning by remote wireless mode. The system has been successfully applied in the Minzhi station project of Shenzhen Metro Line 5 to ensure the normal operation of existing railway. Meanwhile, the high accuracy and reliability of the system are also verified by the engineering applications. It can be applied to monitor the settlement of similar projects.

Abstract: Sufficient sensor information is needed in the control of intelligent lower limb prosthesis. Sensor system includes MEMS Accelerometer and MEMS Gyroscope. The sensor system is installed in prosthetic socket. Walking information is obtained using this system. Hip joint and knee joint motion is measured by Vicon MX system. the angle, velocity and acceleration of Hip joint and knee joint is analyzed. The signal of sensor system is collected by Quarc system. Using the wavelet analysis method, characteristic values is extracted from the measurement signal after errors separation process. The results of experiment indicate that the sensor system has advantages of small size, sensitive response,quick examine,convinence to take with and use and so on. The system is very suitable for the information acquisition.

Abstract: To enhance decay resistance, the effect of heat treatment and the variation of chemical composition on Chinese Fir and Pine were investigated in this study — heat treatment temperature was 170°C, 190°C and 210°C, respectively, heat treatment time was 2, 3 and 4hours, respectively. Both of them were subsequently exposed to white-rot fungus and brown-rot fungus. The results showed that:(1) With the increasing of the heat treatment, decay resistance of Chinese Fir and Pine were improved, anti-corrosion of Pine after being heat treated at 190°C which were exposed to write-rot fungus can reach I, anti-corrosion of Chinese Fir after being heat treated at 170°C treated which were exposed to brown-rot fungus could reach I yet, After being heat treated at 210°C for 3 hours , the Chinese fir samples had no measurable weight loss when exposed to the write-rot fungus.(2) There was no remarkable influence on both Chinese Fir and Pine by heat treatment time.(3) The moisture content of Chinese Fir and Pine were lower than the moisture content that the rot fungus need, macromolecule chains such as cellulose and hemicellulose broke down, their contents decreased, and the hemicellulose decomposed into acetic acid, they prevented the growth of rot fungus.

Abstract: In order to improve the dynamic performance of five-axis heavy vehicle, a variable universe fuzzy control method is proposed to optimize suspension parameters. Five-axis multi-body dynamic model including electro-hydraulic proportional valve was firstly established in software ADAMS/Car. The variable universe fuzzy controller based on fuzzy neural network was also designed in MATLAB/Simulink, and then the co-simulation was conducted. The dynamic characteristics of five-axis heavy vehicle are studied to verify the effect of suspension parameters optimized by variable universe fuzzy control method in the A, B and C-level random pavement and different speed conditions. Simulation results show that compared with passive suspension, the real-time optimization of variable fuzzy control based on FNN can improve the ride comfort and the dynamic load of tire. Under different driving conditions, ride comfort can be increased by about 25%-30%, and the dynamic load of tire generally decreases by 25%-35%. Therefore this method has a certain practicability and effectiveness.