Advanced Materials Research Vols. 655-657

Abstract: Fault diagnosis can be achieved by the cluster analysis process. We give a complete similarity measurement method and a cluster criterion function defined by modularity increment in complex network community detection. An agglomerative cluster method is proposed and the diagnosis rules are extracted to fault diagnosis for the marine engine system. Using the samples collected from self-manufactured marine engine room simulator, fault diagnosis simulation experiment is carried out to verify the algorithm performance. The results show that the method is accurate and less time-consuming, and is able to recognize the fault pattern which does not exist in the fault history data.

Abstract: At present, the flight velocity and flight performance of an aircraft are higher, so that aerodynamic noise caused by an engine jet in the take-off and flight processes can reach 160 dB. The high strength of the jet aerodynamic noise is very harmful to vehicle drivers, vehicle structures and airborne equipments. Two numerical calculation methods to aerodynamic noise, the FW-H acoustic analogy method and the FW-H acoustic analogy and boundary element combining method, were introduced. These two methods were used to predict the aerodynamic noise, and the numerical calculation results were compared with the physical experimental results. Results show that the FW-H acoustic analogy method can predict aerodynamic noise. However, it cannot predict the sound field distribution. The FW-H acoustic analogy and boundary element combining method is able to predict the sound field distribution with sound reflection.

Abstract: This article has studied the correlation relationship between the spectral features of polluted leaf surface of Ficus microcarpa and air dustfall in Guangzhou City. The results show that the spectral reflectance of leaves in the industrial area and large traffic area is 3-5.5% higher than that of leaves in cleaning area in the visible band, but is 10-15% lower in the near infrared band. Compared to the spectral reflectance of the cleaned leaf, the spectral reflectance of leaf on nature dirty is 6.6％ higher in the visible band and 25.6% lower in the infrared band. The spectral reflectance difference between dirty leaf and cleaned leaf in the infrared band has a strong correlation with air dustfall in Guangzhou city. The correlation coefficient is 0.821. It is simple and convenient, fast, economic method to monitor the air dustfall using the spectral characteristic of Ficus microcarpa’s leaf.

Abstract: The bimorph piezoelectric cantilever model for vibration energy harvesting was established to analyse its natural frequency and generating performance according to Euler-Bernoulli theory. The influence of the length and thickness of piezoelectric cantilever on natural frequency and generating voltage was discussed by computing the cantilever equivalent stiffness. Experimental investigation was performed to measure its natural frequency and output generating voltage of bimorph piezoelectric cantilever, and the effect of cantilever with different proof mass and structural parameters on generating performance was also analysed. Theoretical results of bimorph piezoelectric cantilever are compared with experimental results qualitatively, good correlations are observed.

Abstract: In order to solve the inconsistent problem of multi-layer connection and vibration in each layer, a butterfly piezoelectric generator with multilayer cantilever beams is designed. The generator is mainly constituted by butterfly multilayer cantilever beams and mass subassembly two parts. Physical devices of butterfly generator and typical piezoelectric cantilever are fabricated respectively. The experimental setup is also put up for the testing of resonant frequency and output voltage. It can be found that each layer of multilayer generator has a similar output voltage and resonant frequency to the typical one with same geometric and material parameters. So each layer in butterfly piezoelectric generator can be simplified as a typical cantilever beam for researching and analyzing.

Abstract: The accurate measurement of nonequilibrium charge carrier lifetime is of vital significance in research and manufacture of crystalline silicon solar cells. A testing equipment based on a contactless microwave phase method was implemented by being embedded with GPIB, FPGA and a lock-in analyzer. A friendly operation interface was developed, based on the graphic programming language LabVIEW. The virtue of the equipment is achieved by automatic data acquisition and processing, which improves the automatization, efficiency and accuracy of the measurement.

Abstract: The liquid crystal (LCD) biosensor is a new research area of sensor technology, which integrates the modern biotechnology and advanced electronic sensing technology. The feasibility and the principle of the LCD biosensor were mainly introduced in this paper. The chitosan films exhibited cholesteric phase LCD texture which can be seen by using the polarizing microscope (POM), and there is a main endothermic peak and exothermic peak of chitosan LCD solution in the DSC heating curve and cooling curve respectively. Chitosan maybe will be used as a sensing material by using its LCD characteristics. The development prospects are predicted.

Abstract: The paper proposes wireless sensor clustering routing protocol based on ant colony algorithm(ACO). The method firstly uses the network self-topology to get a stable cluster structure based on modularity clustering algorithm; secondly make a new cluster-head selection function according to each cluster node residual energy and the distribution of cluster node; then we propose inter-cluster multi-hop routing algorithm based on ant colony optimization, which in order to balance the energy between consumption on the transmission path and residual one of cluster-head node, developing new ant transmission probability and pheromone updating strategy, we verify the validity of algorithm through simulation.

Abstract: The accuracy and traceability of measurement at nano-scale are directly related to nano-fabrication. Nanostep is typical structure, so the measurement and characterization of nanosteps are important to improve the accuracy of nano-fabrication. This paper studies on the relationship between the morphologic features of nanosteps and the processing parameters of a dual beam Focused Ion Beam (FIB). Nanosteps are fabricated with different depth of 50nm and 30nm. The experimental results show the depths of the nanosteps are affected by the sequence of the process and the processing energy. Although the relationship between the depth and process duration is linear, the depths of the nanosteps are not consistent with the design. The dimensions of the nanosteps at different positions are not constant because of the varying slope of the bottom and sidewall. It is necessary to optimize the processing parameters to achieve the designed dimensions.

Abstract: Based on the geometric characteristics of maximum inscribed circle (MIC) and Minimum circumscribed circle (MCC), a novel method for roundness error evaluation using Geometric Approximation Searching Algorithm (GASA) has been presented in this paper. First, a square is allocated by taking the predetermined reference point as initial reference point, and the radius value of all the measured points are calculated by regarding each vertex of the square and the initial reference point as the ideal centres respectively. Second, the minimum and maximum radius are obtained when each vertex of the square and the initial reference point as the ideal centre point. Final, compare these radius and arrange the square repeatedly. Repeat the steps, the roundness error of the maximum inscribed circle can be obtained complies with ANSI and ISO standards. The experimental results show that this algorithm is effective and accurate.