Advanced Materials Research Vols. 201-203

Abstract: In this paper, the thickness of the different layer of the multiple-layer homogeneous structure. is optimized designed on the condition that the absorption effort is the best Using the transfer matrix of sound pressure and particle velocity of each layer and the continuity condition at the interface between two lagers, the absorption coefficient of the multiple-layer homogeneous structure is deduced. According to the absorption coefficient, the thickness of different layer is optimized designed on the condition that the absorption effort is the best when the sound wave incident to the multiple-layer homogeneous structure with different frequency. In the last, an experiment is carried out, and the experiment results test the theoretical analysis is correct which can be applied to solve the same kind problem.

Abstract: This research is to extend Ziegler-Nichols based PID controller design method to the intelligent fuzzy PID controller design of a Scanning Probe Microscope (SPM) system, thus the relative stability can be reserved. In addition, one can see the hysteresis and parameters variation effects of the force actuator can be reduced. This improvement had been verified by practical implementation. Comparing the results with the design with the Ziegler-Nichols based PID controller, one can see that the proposed system is more robust.

Abstract: Mixed traffic flow is the basic characteristic of urban traffic. In pedestrian crosswalk without signals, there are a lot of traffic conflicts between pedestrians and vehicles crossing the intersection, which badly affects the traffic capacity and increases security risks. Through an analysis on the behavior pattern of pedestrians and vehicles crossing through the crosswalk, the paper first proposes a model based on dirty-face game to study the behavior characteristics of intersection traffic, which perfects analysis approaches to the traffic capacity of road crossing and the mixed traffic flow theory.

Abstract: With the development of modem broadband radar, amount of reaserchers focus on broadband radar echo signal acquisitions and feature extraction of the target. Due to the large bandwidth as high as several MHz, the time interleaved ADC system is playing an important in radar echo systems, but this structure will bring in channel dismatch errors. The paper gave an explicit analysis of such three channel mismatch errors, and established the formulas of spectrum when all three mismatch errors exist together. Then presented the measure errors algorithm combined three errors according to the formulas of spectrum and the effective calibration algorithm．The algorithm was implemented in FPGA at last.

Abstract: In this paper, a novel approach is proposed to extract features from the bispectra of mechanical fault signals using non-negative tensor factorization (NTF) for the purpose of establishing an intrinsic relationship between mechanical faults and extracted characteristics. First, the bispectra of mechanical signals are obtained and stacked to form a three-dimensional (3D) tensor. Then, an NTF method is applied to extract features, which are represented by a series of “basis images,” from this tensor. Finally, coefficients indicating these basis images’ weights in constituting original bispectral images are calculated for fault classification. Experiments on fault datasets of gearboxes showed that the results of the proposed method not only reveal some nonlinear features of the system, but also have low data dimensions and intuitive meanings with regard to fault characteristic frequencies, which bring great convenience to an explanation of the relationship between mechanical faults and the corresponding bispectra.

Abstract: In view of the insufficiency of central air-conditioning system that FCU, water pumps and air blower’s movement connot match with the actual operating load when varying duty, an energy saving control system for central air-conditioning based on terminal temperature measuring and frequency conversion control technology is proposed. This system can real-time measure different floors’ and nods’ temperatures in the building, and export orders to control the frequency of FCU, chilled water pump, cooling water pump and cooling tower air blower. To overcome big delay, large inertia and variable condition of control object, the dnamic fzzy nural network algorithm(DFNN), is applied into the control system. According to the practical running situations, the energy saving control system has advantages as high energy saving rate, high stability, good maintainability, which may be promoted the application vigorously.

Abstract: Robot touch sensation is an important feeling pattern for robots to gain environment information in non-vision sensor domain, in this thesis, the writer uses silicon piezoresistive sensor to form Array haptic system, and form gray level image from collected pressure and temperature information, and judge the slippage condition of objects through image preprocessing, region segmentation, centroid identification, and show the result picturesquely by using image. The experimental result shows that this method can fastly and effectively judge the slippage condition of objects, and it can intuitionally shows the condition of distribution of object temperature.

Abstract: Three-layer micro perforated plate of the automotive body is researched. Acoustic impedance of the three-layer microperforated plate of the automotive body is attained according to the equivalent circuit, thus absorption coefficient is attained. Different microperforated plate with different porosity, different diameter, different thickness, different depth of cavity of the automotive body is analyzed and some conclusion is drawn to applied some theory to design these types of the micro perforated plates of the automotive body.

Abstract: For the insufficient setting load of powered props of powered supports, an automatic booster valve, which can work continuously, is development by further analyzing the principle of automatic booster setting load system of powered supports. A simulation model is established based on AMESim ,and it is discussed that the internal relations between the efficiency ,pressure ratio and stroke of the automatic booster valve, the theoretical data and support are offered on solving the problem of insufficient and inhomogeneous setting force of powered support, it is shown that the automatic booster valve have the functions that lifting the leg by low pressure and mass flow and boosting automatically by high pressure and small flow,which can ensure the requirement on the setting load of powered supports, provide advantageous conditions for safety and efficiency in coal mine production.

Abstract: Tubing plugging often occurs and brings some difficulties to industrial production. This paper proposes a simple pneumatic impactor which can instantaneously generate great acceleration by a reservoir to shock and smash calcium monohydrate bonding in the tubing inwall. The working principle and the mathematical model of the impactor are introduced in detail. In order to obtain its dynamic characteristic, the simulation is performed. The results show that during the movement of the piston back pressure occurs due to the outlet chamber squeezed by the piston with a high speed, and with inlet pressure increasing positions of the piston with different peak velocities are almost the same. This impactor can be used to unplug tubings in oil or gas well.