Applied Mechanics and Materials Vols. 494-495

Abstract: Using spectrum signal acquires the information of printing colors, it has the advantages of fast response speed, wide color gamut range, high resolution, etc. And it is the key techniques in the print ink control. In this paper, it introduces a broadband and large dynamic spectrum signal acquisition circuit. It uses micro photoelectric diode array spectrum sensors, processing analog spectra signal with broadband low noise amplifier. It realized the low noise large dynamic performance through analog-to-digital converter (A/D), signal preprocessing and the optimal design of power circuit. Its spectral wavelength resolution is 0.3 nm, range from 15 to 400 lumens (lm) illumination spectrum signal acquisition, within the scope of the design of the system signal-to-noise ratio to 45 dB.

Abstract: The components of the ultrasonic phased array transmitting system is analyzed and theoretical model of ultrasonic phased array transmitting system is developed. The simulation result shows that the model is reasonable.

Abstract: The optimal placement of actuators is studied with the combination of numerical calculation and modal test methods. The results indicate that the optimal excitation position is close to the maximum displacement of a cantilever beam, but the conclusion is not the same as a simply supported beam. The calculation results are consistent with the experimental results, which show that the approach in the present study is correct, and can be popularized.

Abstract: Giant Magneto-Impedance (GMI) sensor is a new type of magnetic sensors. Comparing with traditional sensors, GMI sensor has the advantages of high sensitivity, good reliability, wide measuring range and small size and is potential in resisting harsh environment. In the paper, circuit systems both in overseas and domestic researches are analyzed, shortcomings of the systems are pointed out and some improvement ideas are presented. At last, elaborate the development trends of GMI sensor's circuit system to find a practical solution for data processing technology.

Abstract: Data from sensor array are often arranged in three-dimension as sample × time × sensor. Traditional methods are mainly used for two-dimension data. When such methods are applied, some time-profile information will lost. To acquire the information of samples, sensors and times more exactly, parallel factor analysis (PARAFAC) is investigated to deal with three-way data array. Through the analysis and classification of three kinds of oil odor samples, the performance of PARAFAC in gas sensor array signal analysis is verified and validated.

Abstract: . With the advantages of high sensitivity, good reliability, small size and being good at resisting bad environment, GMI sensors are potential in applications of engineering. Generally speaking, incentive scheme of GMI sensors determines whether the GMI effect can be generated sufficiently, which may have an important effect on the sensors sensitivity and measurement range. The paper analyses current GMI sensors incentive scheme, then proposes two incentive optimization designs. The schemes can fully generate non-magnetic materials GMI effect. Meanwhile, performance of the sensor can be greatly improved.

Abstract: We studied rapid moisture determination in lignitic coal samples using near-infrared (NIR) spectrometry technique. This research applied support vector regression (SVR) and discrete wavelet transform (DWT) to analyze NIR spectra. Firstly, NIR spectra were pre-processed by DWT for fitting and compression. Then, DWT coefficients were used to build support vector regression model. Through parameters optimization, the results show that DWT-SVR can obtain satisfactory performance for moisture determination in lignitic coal samples.

Abstract: Along with the continuous development of image precision measurement technique, in the precision imaging system, automatic focusing technique is becoming more and more intelligent. Automatic focusing technique of image precision measurement based on edge detection has become a hot topic in the current research field. On the basis of edge structure features, this paper firstly analyses the commonly used edge detection technique in the image precise measurement. Based on this, it combines the SUSAN filtering algorithm for different edge image value types to introduce Gauss filter parameter σ to locate the edge, so as to improve automatic focusing function of imaging. The experimental results have shown that the method can obviously filter noise, and has a significant automatic focusing effect.

Abstract: In this paper, a set of industrial X-ray film digitizing and automatic identification system is established with machine vision equipment. With this system, the industrial film can be digitalized rapidly and in high space resolution reaching to 860 DPI. The machine vision equipment includes linear CCD, light source, lens, aperture and film-moving machine. The controller is a master-slave mode, which includes a PC as the upper computer and an embedded system as the lower computer. The embedded system is composed by ARM and FPGA modules, which can control four axis motors and transmit an external trigger signals to the CCD in real-time. At last, a series of image processing algorithm is also developed in this paper to identify an industrial film that is captured to test coupling alignment of the casing pipes. The testing accuracy is 0.06mm.

Abstract: In order to overcome the disconnection and high cost and maintenance difficulties of the conventional data collection systems for structure monitoring of long span bridge, we developed a low-cost and effective data acquisition system composed of several wireless communication modules connected to vibrating wire type sensors. This system has the function to change conventional wire-based data collector into wireless one instantly. The prototype of wireless data acquisition system for vibrating sensors is described in this paper. Laboratory tests demonstrate that the wireless data acquisition system is of high accuracy and good stability. In addition, the application of this system to the strain monitoring of a large steel box arch shows the wireless data acquisition system with good performance improve the efficiency of data acquisition and reduces the cost of monitoring.