Advanced Materials Research Vols. 945-949

Abstract: Faced to low detection rate and low credibility of single sensor because of noise , this paper proposes Bayesian fusion based on multisensory system, whose detec tion rate and credibility are discussed. After simulation , it is concluded that the Bayesian fusion is a feasible detection method with high precision that improves detection rate and credibility.

Abstract: If the nodes in a multi-media data transmission system can not meet low power in traditional wireless sensor networks (WSNs), it will greatly reduce the network life cycle. On the basis of quantized compressive sensing (QCS), this paper presents a communication model which can analyze the impact of uniform quantization coding and Hoffman coding on image’s transmission and reconstruction. According to the prior probability of image measurement, this paper proposes a novel scheme for non-uniform quantizer.The simulation results show that the multi-media data transmission system can obtain images effectively and reduce the distortion by using the proposed scheme.

Abstract: The actual use conditions of force transducer is differences between the factory verification conditions, so based on the structure and working principles, this article is aimed at accurate calibration and proper use of force transducer. Through the CAE simulations and calibration experiments in actual working conditions which are the installation pre-tightening force, structure of fittings and pedestal’s hardness, analyses the output signals of force transducer. Force standard machine was carried out on the calibration experiment to verify the correctness of the numerical simulation. And then the outcomes obtained by numerical simulations and the calibration experiments, it studies the differences of every output performance index of force transducers in different working conditions above-mentioned.

Abstract: In this paper, we propose a special Multi-class SVMs (MSVM) data fusion strategy which is applied to classify vehicle based on multiple pavement structural strain time histories. The centralized and distributed fusion strategies are applied to combine information from several data sources. In the centralized strategy, all information from several data sources is centralized and combined to construct an input space. Then a MSVM classifier is trained. In distributed schemes, the individual data sources are processed separately and modeled by using the MSVM. Then new data fusion strategies are used to combine the information from the individual MSVM to acquire the final classification outputs. Two popular Multi-class SVMs algorithms (One-against-all OAA, One-against-one OAO) are used to construct classifier based on aforementioned two fusion strategies, respectively. The results are compared between SVM-based fusion approach and single data source SVM using two MSVM algorithms, respectively. The result shows this SVM-based fusion approach significantly improves the results of classification accuracy and robustness. The proposed Multisensor data fusion methods can also be applied in other fields.

Abstract: In the chemical industry, it is necessary to detect the chemical reaction temperature in the tank online and real-time to ensure the chemical reactions normally and prevent accidents. A chemical reaction tank temperature acquisition system based on ZigBee technology is proposed. The hardware and software architecture of the new designed system is described in details in this paper. The new designed system overcomes the disadvantages of manual detection or wired method. The field experiments show that the system has the advantages of high precision, flexibility, anti-interference, real-time, and Multi-point, etc.

Abstract: The structure of conventional bobbin probe was modified to improve the detection sensitivity of defects in metal tube. Based on the results of finite element simulation, several types of modified probes are fabricated and used to detect artificial defects in tube and the defect signals are acquired and analyzed. The simulation and experimental results verified that the modified eddy current probes are more sensitive to non-axial defects than conventional bobbin probe and can improve the reliability of tube inspection.

Abstract: Organic photosensor made of poly [N-9′′-heptadecanyl-2,7-carbazole-alt-5,5-(4′, 7′-di-2-thienyl-2′,1′,3′-benzothiadiazole)] (PCDTBT) are promising candidates for bio-sensing applications. This paper investigates the optoelectronic characteristics of 4 different structures through simulation, utilizing PCDTBT as the active absorption layer. The scheme 1 is formed by placing the PCDTBT layer on top of a SiO₂ layer, and then interdigitated electrodes made of aluminium are placed onto PCDTBT. As to the scheme 2, the semiconductor layer is placed between an aluminium layer (bottom) and glass (top) layer coated with thick transparent interdigitated electrodes made of indium tin oxide (ITO). Regarding to scheme 3, layers from bottom to top are SiO₂, cathode, PCDTBT and anode. Cathode has the same area as SiO₂ and PCDTBT layers, but anode covers only partial of the semiconductor. Finally, in the scheme 4, the semiconductor layer is also placed over SiO₂ layer but here the anode and cathode are limiting the PCDTBT layer sides, having the same area for both sides. All schemes have same volume of semiconductor. The simulations have been realized in dark conditions and under light intensities 100 mW/cm² in the wavelength range of 400-550 nm. The best results were obtained for scheme 2, organic photoconductor with Metal-Semiconductor-Metal structure. For in this scheme which is under the conditions of 2 V bias, 500 nm wavelength and 100 mW/cm² illumination, the photocurrent, the internal and external quantum efficiency obtained were 8.53 μA, 88% and 45% respectively. As a conclusion, the scheme 2 Glass/PCDTBT/Aluminium with transparent electrodes has reached high performance desirable for bio-sensing.

Abstract: In this paper, the equivalent model of high frequency current transformers (HFCT) for partial discharge online monitoring and its major parameters’ influence on amplitude-and phase frequency characteristics are derived. An optimized design for HFCT for partial discharge online monitoring is summarized.

Abstract: There are many factors that can effect on accuracy of reflective intensity-modulated fiber optic sensor (RIM-FOS). Operational object is a major element among them to fiber optic sensor, which is used in measurement of dynamic and static clearance of steam turbine, studied in this topic. For this reason, this letter researches on scattering characteristic of light on surface of medium and distributed function of outline of medium’s surface, and computes and analyzes on their effect on measuring. All of above are benefit to improve accuracy of this kind of sensors.

Abstract: In the present study, we describe an electrochemical sensor for Hg2+ detection by using the DNA probe. Two specific sequence for the probes, one has to ensure that the probe A hybridized with probe B modified on CdS nanoparticle to form stable DNA duplexes only in the presence of Hg2+ at a given operating temperature. After dissolving the CdS particles from the electrode, a mercury-film electrode was used for electrochemical detection of these Cd2+ ions which offered sensitive electrochemical signal transduction.The limit of detection of this assay in buffer is 12 nM. The detection was also specific for Hg2+ without being affected by the other metal ions, such as Cd2+,Li+,Ba2+,K+,Ca2+.