Applied Mechanics and Materials Vols. 239-240

Abstract: An interdigitated array microelectrodes (IDAMs) based impedance biosensor in combination with immunomagnetic separation was developed for rapid detection of avian influenza virus (AIV) subtype H5. Streptavidin-coated magnetic nanobeads were immobilized onto the biotin-labeled anti-H5 monoclonal antibodies to capture AIV H5 (e.g., H5N1) from sample solutions by the specific immunoreaction and form antibodies coated nanobeads-AIV complexes. Then these complexes were separated and concentrated by a magnetic field and the impedance magnitude was measured by IDAMs in a frequency range from 20 Hz to 1 MHz. The sensitivity and specificity of this biosensor were investigated. The biosensor could detect as few as 2-1 HA unit/50 μl of inactivated AIV H5N1. A linear relationship between the change of impedance magnitude and the logarithmic value of AIV H5N1 concentration was found in the range of 2-1 to 24 HA unit/50 μl. Non-target viruses, such as AIV subtype H1 and Newcastle disease virus, could not induce detectable signals. Equivalent circuit analysis showed that the medium resistance was responsible for the impedance change caused by the presence of AIV H5N1. The whole detection process from sampling to impedance measurement was able to be completed within 1.5 h.

Abstract: Traditional transmission line tower grounding resistance measurements have many shortcomings, in order to make up the defects the model of transmission line tower with good conductor wires and multiple grounding leads was builded, and then the algorithm of tower grounding resistance on-line measurement was proposed. On this condition, a system based on this algorithm was designed and further analysis of the error during data processing was conducted. At last, the MATLAB simulation indicates that the algorithm has a accuracy that meets the practical requirements.

Abstract: Waveform optimization for multiple-input multiple-output (MIMO) radar systems for good autocorrelation and crosscorrelation properties based on the direct design of the set of orthogonal transmitted time series is considered. Exploiting the orthogonality of non identical walsh functions, which have been used successfully in spread spectrum communication, the Walsh-Hadamard matrix is used as the orthogonal binary signal set followed by the simulated annealing statistical optimization tool to provide an optimal orthogonal binary signal set with the desired correlation properties

Abstract: The prediction of chaotic time sequence based on AR model is studied. The forming mechanism of the first-order Bragg lines of sea clutter is analyzed. According to the signal characteristic of sea clutter, a sea clutter time sequence predictor and a skywave radar sea clutter suppression system based on AR model are presented. The cancelling of sea clutter is achieved by subtracting the predicted signal from the original signal. The simulation results show that the first-order Bragg lines in the signal were suppressed effectively after processed by this sea clutter suppression system, the detecting performance of skywave radar was increased dominatively.

Abstract: Current source with high output impedance is a key part in bioelectrical impedance measurement. In this paper, we presented a design of a current source based on the improved Howland current pump circuit. Then the performance of the proposed current source was simulated in Multisim software. The designed current source was implemented and its output impedance was tested. Both the simulated and tested results show that the proposed current source is a good choice for BI measurement.

Abstract: This paper designed a bioelectrical impedance spectroscopy (BIS) measurement system based on the integrated impedance converter AD5933. The working principle of the AD5933 was briefly introduced, and a bipolar BIS measurement device was designed. The AD5933 can be controlled by MCU STC89LE516AD through an I2C bus. The software of the BIS device was written in C51 language and provides a friendly human-machine interface. Preliminary experiment showed that the impedance measurement error at different frequencies is less than 3% and found that the measurement accuracy is relatively high for larger resistor.

Abstract: A novel watershed algorithm using mountain areas simulation method to segment the field emission images was proposed for the first time. In the algorithm, field emission sites in the images are compared to many mountaintops. The small fluctuations in the mountains are first erased by filling method. And then the traditional watershed transform is applied to get the mountain areas roughly. At last the parameters of the relative height needed for a mountaintop are used to segment the field emission sites by a series image process of dilation and comparation. This segmentation method is very easy to be accomplished in MATLAB and have high efficiency. Results show that the improved watershed algorithm is feasible in analyzing field emission properties and some other applications.

Abstract: With wide range applications of piezoelectric ceramics, its performance parameters test possesses an important role in electronic measuring industry. This paper describes the principles and methods of piezoelectric ceramic performance, parameters testing as well as various impedance analyses. An impedance analysis hardware system based on LabVIEW is designed application of USB-6251 board to realize the acquisition and process of the simulation signal. Experiment in this study shows that the impedance analysis hardware system based on LabVIEW has the characteristics of practicality, stability, reliability, easy to install and upgrade in measurement of piezoelectric ceramic.

Abstract: An improved project based on decision trees in noisy environments is proposed for robust endpoints detection. Firstly, the noise level of the environment is estimated by wavelet decomposition, and then whether the denoising process is done according to the noise level is determined. Next, the thresholds are obtained by decision trees for the signal. Finally, endpoints are detected by the double thresholds on different importance of the energy and zero-crossing rate (ZCR) in the corresponding situation. The simulation results indicate that the proposed method based on noise estimation can obtain the same accurate data by computing less than the one with decision trees.

Abstract: Quality of Experience is referred to as an important index for measuring how well the user's requirements are satisfied, and many methods have been presented to evaluate speech quality. But they cannot identify the kind of disturbances when the quality of speech is not good. This paper aims at proposing a method which can identify the kind of disturbances lowering the Quality of Experience. The approach proposed is based on PESQ and P563 algorithms. It adopted asymmetrical factor of PESQ and cosine distance in frequency domain to compare original signal with degraded signal. And a new time realignment method and temporal masking method were used to improve detection precision in wireless environments. This new algorithm is tested in real world including GSM and UMTS environments. The results indicate that this algorithm is helpful for detecting noise, single pass, cross pass and echoing automatically.