Applied Mechanics and Materials Vols. 105-107

Abstract: Abstract A tungsten electrode modified with polyaniline was prepared as working electrode, the platinum wire electrode for counter electrode, and the saturated Ag/AgCl redox system for reference electrode, with the base on solution H2SO4 (1.5mol/L) vs. aniline solution 0.1mol/L. The sensor showed a Nernst response in the pH range of 2~12 and a response time less than 1 min. Connected the tungsten filament electrode and silver wire electrode (mentioned above) to the anode and cathode of the pHS-25 type pH meter respectively, inserted the electrodes to the measured positions of the sample, and then recorded the potential reading when the potential value was stable, the results would be quantified by the curve (E-pH curve) finally.The sensor has been successfully employed to determine pH in the crucian from the live fish to the putrefied fish.

Abstract: Infrared sensor arrays is a new type of apperceiving system of robots, which are made up of large-area and flexible sensors with data processing capabilities. In order to meet the requirement of real-time obstacle avoidance, sensors which can be covered on the surface of robots were designed to apperceive the environment and provide the environmental information by the infrared sensors and the controlling circuit on them. To get rid of the environmental disturbance to the infrared sensors, and to meet the requirement of system precision, real time and stability, a kind of reconfigurable architecture based on DSP+FPGA was designed and a kind of spectrum analyzing method based on FFT (Fast Fourier Transform) was used. Tests of the system with different color papers as the measured subjects showed that the output of sensor arrays had low sensitivity.

Abstract: This paper covers the requirement and measurement of sound quality in the surround sound classroom. Based on the characteristics of the sound field, this paper specially deals with the design of acoustics requirement of the characteristics of reverberation frequency and sound propagation. In order to meet the requirements of recording in signal to noise ratio, comprehensive methods in noise decrease are adopted in design, which include the reduction of noise in room background. Through the checking of the testing data and the evaluation of the users, various acoustics norms meet the requirements of acoustics and the demands of the using.

Abstract: The traditional facilities that used to find range are mostly based on laser or ultrasonic. Now, based on binocular parallax of human eyes, we advance a method used to get the distance by measuring the offset on image panel. On this foundation, we also analyze the error in forward. The academic analysis indicate that the measurement would be impacted severely by transverse offset and angle-measuring offset, in contrast, much slightly by lengthways offset. When we put this facility into practice, this facility can suffice practical demand completely if we select the space between bi-camera and the focus of facility rationally.

Abstract: To investigate the micro-mechanics property of cucumber mesophyll cell wall, an experiment was conducted at nanolevel scale with the help of nanoindentation masurement system after the tissue of cucumber leaf has been treated of fixing,dehydrating,embedding,slicing for the mesophyll. Loading-unloading curve showed: the cell wall deformed elastically before the stress reach 1.0MPa, after that, the cell wall deformed plastically;It also can be seen in the range elastic deformation that the stress-strain is nonlinear relationship .

Abstract: To study the problem of high precision, the reason why error appears in the ultrasonic positioning process is analyzed. To decrease the effect of error, this paper raises the algorithm of curve-fitting extrapolation and redundant information fusion. The experiment and contrast on precision between this algorithm and other classical ones demonstrate that, the new algorithm could effectively control measurement errors and raise the precision of ultrasonic positioning.

Abstract: The traffic lights identification algorithms is an important part of the platform for automatic driving technology and it is also applied in the remote control system. As the absolute standard of behavior instruction, lights are the most firsthand object to judge. Image recognition technology has been applied in the Gray Spaces and HSI space, but Comparing with RGB color space, the latter is easier to understand and realize. This paper puts forward a kind of identification algorithm for single or multiple lights. According to the target image numerical characteristics in the RGB color space and judging from the target area needed and the related parameters extracted, The feasibility of this algorithm is proved in theory and application and the experimental results are satisfactory in the Matlab environment.

Abstract: Based on the analysis of automobile aerodynamic noise generation mechanisms and the components of interior wind noise, the spectra characteristics and spatial distribution rule of sound level of interior wind noise were investigated at first, then the frequency characteristics and noise level under different wind speeds, different yaw angles in SAWTC full-scale aeroacoustic wind tunnel were studied. The results show that: the interior noise level was nearly symmetric on vehicle left and right side, noise level of outboard ear was normally higher than that of inboard ear. The frequency characteristics under different wind speeds were almost the same, the linear OASPL of interior noise increased at about 4.4th power and A-weighted OASPL at about 5.5th power of wind speed. In addition, the acoustic power increased as yaw angle rose up, and noise level by leeward side was normally higher than that by windward under the same yaw angle.

Abstract: The error distribution of residual stress tested by X-ray diffraction on 7050 aluminum alloy was studied. In this paper, residual stress was measured, independently and repeatedly, many times on 7050 aluminum alloy with X-ray diffraction, then the errors about 50 stress values within the range of 30MPa were analyzed by the hypothesis testing. The results indicate that the errors of the residual stress measurement on 7050 aluminum alloy were followed the law of normal distribution about and the errors can be estimated by the least square calculator. The research lays the foundation to subsequent researches on the inherent law of the residual stress measurement with X-ray diffraction and the residual stress distribution and accuracy of stress of material surface.

Abstract: Underwater plasma acoustic source (UPAS) with high voltage pulse arc discharge produced pressure wave has the advantage of adjustable pulse length, high source level output, and no pollution to the environment. In recent years, this kind of source has been gradually used in domain as long range target detection, geo-acoustic profile measurement, and frogman threats deposal etc. While for a fairly long time, we’re lack of research on the company product of sound—light. In this paper, we measured the opto-spectrum of UPAS by experiment, and found its spectrum is of continuous spectrum and its dominant energy is around 500nm, if we raise the discharge voltage, reduce the gap distance of the tips, the spectrum amplitude and half peak amplitude width will increase, and if we change steel tips with copper tips, the light energy distribution and amplitude of the spectrum will change.