Advanced Materials Research Vols. 718-720

Abstract: This paper introduces one method to design a vibration diagnosis device from several sides such as components choosing, circuit designing and soft programming. This device consists of ATmega128 MCU, acceleration transducer, TLC2543 and other peripheral components and it can conveniently acquire and analysis signal. The resource used to test the device was supported by Function Generator and amplified by Power Amplifier. The data was exported to PC and graphed by MatLAB application, and then made a comparison with the theoretical graph to prove the method validity. This design has simple circuit and small codes, but it can capture mechanical working state accurately, so it has preferably practical value and economic benefit.

Abstract: Different topologies and tuning of ladder filter made up of film bulk acoustic resonator (FBAR) using Modified Butterworth-Van Dyke (MBVD) model is studied. The influence to the filter by singly adding series or shunt FBAR is separately simulated. The three-stage ladder filter with different topologies is especially investigated. The five-stage ladder filter is studied by changing the inherent components of L_m and C₀ in the FBAR.

Abstract: The display monitors have been developed rapidly. The traditional broadcasting systems employed interlaced scanning format to hide motion artifacts. The procedure of converting interlaced video into a progressive formatted video called frame rate conversion. However, due to the variety of progressive scanning formats, all interlaced scanned contents must be transformed progressive format. In this paper, we study optimal number of window size for frame format conversion method. The objective and subjective performance are shown in performance analysis section.

Abstract: The typical speaker for cellular phone is composed of magnet, coil, base-film and diaphragm with a structure that laminated a foam sheet and aluminum sheets. A heterogeneous foam sheet which has an uneven elastic modulus was used for a conventional diaphragm, and it reduced an acoustic performance of a conventional speaker. Recently a homogeneous and thin foam sheet was newly developed. The purpose of this study is to improve the acoustic characteristics of the micro speaker by changing thickness and foaming ratio of the newly developed foam sheet. Frequency characteristics and sound pressure level (SPL) were measured by changing foaming ratio of the foam sheet from 2.5 to 5.0 and thickness of the foam sheet from 0.15 mm to 0.30 mm. To clarify the relationship between the design parameter of foam sheet and the frequency characteristics of the micro speaker, natural frequency analysis using finite element method (FEM) was performed. The result of FEM analysis was also compared with the experimental result using a laser doppler velocimetry sensor. It was found that the widest reproducible frequency range was obtained when the foam sheet was used 0.30 mm of thickness and 5.0 of foaming ratio. The reproducible frequency range spread out 15% in comparison with that of a conventional micro speaker.

Abstract: Based on the basic theory of two-way satellite time and frequency transfer (TWSTFT), the mathematical model on real errors of observations is established in this paper. However, the model is rank-deficient. In order to solve this problem effectively, the paper introduces the algorithm of combining parameters, and applies Quasi-Accurate Detection of Gross Errors (QUAD) proposed in reference [ to data pre-processing. The method programs opportune algorithms and resolves the problem of detecting gross errors. In the end, the method has been verified to be successful by calculating and analysing simulated data and practical measured data.

Abstract: The reconstruction quality of in-line holography suffers from the superposition of twin images, which blurs the details and degrades the quality of the object wavefront reconstruction. We present an iterative reconstruction method to eliminate twin image and truthfully retrieve the object wavefront. This algorithm has a better elimination effect and more rapid rate of convergence than other phase retrieval methods. An experimental setup was built with dual cameras recording the holograms simultaneously, thus this technique can be employed for investigating fast dynamic phenomina. The effectiveness of the proposed method is validated using different samples.

Abstract: The problem of planning flight trajectories is studied for multiple unmanned combat aerial vehicles (UCAVs) performing a cooperated air-to-ground target attack (CA/GTA) mission. Several constraints including individual and cooperative constraints are modeled, and an objective function is constructed. Then, the cooperative trajectory planning problem is formulated as a cooperative trajectory optimal control problem (CTP-OCP). Moreover, in order to handle the temporal constraints, a notion of the virtual time based strategy is introduced. Afterwards, a planning algorithm based on the differential flatness theory and B-spline curves is developed to solve the CTP-OCP. Finally, the proposed approach is demonstrated using a typical CA/GTA mission scenario, and the simulation results show that the proposed approach is feasible and effective.

Abstract: Basing on the problems of residual coal in goaf in fully mechanized caving face in hard desorbing coal seam, high content of residual gas, large gas emission, serious gas overrun in return airflow corner and vitiated air, combing the actual situation in 3-219 fully mechanized caving face, the paper has adopted adjacent goaf drainage, drainage in gas drainage technology, formed a low investment cost and effective gas control technology and ensured the safe and efficient production in coal face and has a certain reference to control gas of fully mechanized caving face in hard desorbing coal seam.

Abstract: Coordinated Universal Time (UTC) is regarded as reference time scale for the worldwide time coordination. In order to steer master clock in timekeeping laboratory, it is necessary to make a prediction of UTC-UTC(Lab) time offset for 15~45 days. The prediction is based on two considerations, data size and prediction model. Compared with quadratic polynomial model and grey model, calculating results show a combination model based on 9 months data size is fitter to secular predicting in terms of both stability and accuracy.

Abstract: The network interface is the key position in an intelligent sensor system to realize plug and play. Based on UPnP (Universal Plug and Play) and IEEE 1451serie standards, an IEEE 1451/UPnP bridge is designed to solve the differences of message formats, self-identification description, and device discovery between these two standards. Using UPnP device selection method based on information axiom, the calculation of parameters information is distributed to each NCAP (Network Capable Application Processor) that meeting the service request. The test results indicate that this method simplifies the service discovery process, reduces network interface data traffic overhead, and increases UPnP device service efficiency.