Key Engineering Materials Vols. 609-610

Abstract: As a new functional composite material, Orthotropic Piezoelectric Fiber Composite (OPFC) may be developed conveniently actuators and sensors. By constructing multi-element linear array, the phased array transducers can generate special directional strong actuator power and high sensitivity. The advantage of the transducers is that no mechanical movement is needed to scan an object. Focusing beam is obtained simply only by adjusting a parabolic time delay. The DPSM (distributed point source method) is used to model the ultrasonic field by OPFC linear array transducer. Using this approach, beam directivity and pressure distributions are studied to predict the behavior of focusing as compared to current formulation of traditional transducer. The interaction effect of two OPFC phased array transducers is also modeled in the same medium. Which shows the pressure beam produced by the OPFC array transducer is narrower or more collimated than that produced by the conventional transducer at different angles.

Abstract: A novel demultiplexer based on surface plasmon polaritons with the Bragg structure has been proposed and numerically investigated. The finite difference time domain method with perfectly matched layer absorbing boundary condition is adopted to simulate and study their properties. By introducing Bragg grating structure in the couple area, high extinguish ratio can be achieved. The extinction ratio in 1550nm was 27.5db. Meanwhile, the photonic device can be made in the way of high level of integration, because SPPs has the ability of strongly localizing the signal mode in the area beyond the limit of diffraction. The longitudinal dimension of this demultiplexer was 650nm. The demultiplexer may become a good choice for the design of devices in highly integrated optical circuits.

Abstract: In this paper, diffuser with taper microstructure has been put forward, and the transmission of the light in the taper microstructure has been analyzed. The software of Lighttools has been used to analyze the influence on light intensity distribution of the vertex angle θ, the space between the microstructure L, the diameter ratio of up to down of the microstructure A/B, the cutting output of the microstructure H and the refractive index of the diffuser n1.As a result, the light intensity of the optical axis will increase and visual angle will decrease when the vertex angle θ, the refractive index of the diffuser n1 and the cutting output of the microstructure H increase; the light intensity of the optical axis will increase and visual angle will decrease when the space between the microstructure decrease; with the increasing of the ratio A/B, the light intensity of the optical axis would first increase and then decrease, visual angle would first decrease and then increase. When A/B=0.4, the light intensity gets the maximum value, the visual angle gets the minimum value. The result of the simulation is significant to manufacture and research.

Abstract: With the development of measuring technology,the measuring accuracy of optical glass refractive index of the increasingly high demand,V prism refractometers is major general instrument for measuring the refractive index of optical glass,not only the simple device,convenient measurement,and this method has high precision performance,however,the accuracy is only attained ,which in the regulation of national metrology verification and the introduction of V prism refractometers in the literature,the classic formula calculation principle formula error caused by refractive index has more than .Based on the mechanical structure and optical transmission to improve the original V prism refractometers the refractive index of air,by considering the influence on measurement precision of V prism refractometer,to mathematical modeling of V prism refractometer the principle formula,V can be measured refractive prism refractometer rate accuracy increased to ,measurement repeatability less than ,has important practical significance for realizing high accuracy measurement of the refractive index of optical glass.

Abstract: Micro stereovision technology has been widely used in the small scale micro objects which are not convenient observed for human eyes, through micromanipulation and other ways to do image reconstruction for the object surface and show them out in the computer, but during the operation, the precision problem of the position control system and the microgripper system relation to the precision of micro stereovision system. This paper built the camera projection model based on the micro stereovision system and have done lots of displacement experiments of the mobile platform and the gripper reconstruction experiments of microgripper system, through statistical analyzed these experiment data to show the accuracy of the microgripper system.

Abstract: This paper demonstrates that the deformation of the piezoelectric deformable mirror (DM) is proportional to the transverse piezoelectric coefficient of the lead zirconate titanate (PZT) by the theoretical analysis. The optimal polarization conditions were obtained by experiments to optimize the performance of the DM. After the optimal polarization, the transverse piezoelectric coefficient of the PZT film increases from 350 pm/V to 431 pm/V, which will improve the deformation of the DM.

Abstract: A kind of novel acoustic noise energy scavenger with additional function of noise reduction is introduced in this article. The device consists of energy harvesting membranes and silicon micro perforated panel (MPP) resonant structure. Both of them are all fabricated with silicon wafer in use of MEMS technology. The maximum output power of the energy scavenger is about 14.1μW/m², the maximum open circuit voltage achieves 69.41mV, and the average noise absorption coefficient of the device is higher than 0.7 in the bandwidth of 1500Hz to 6000Hz. The energy collected by the device could be used for driving micro and nano electronic systems.

Abstract: In this paper, we focused the mixed results of the micromixer with the same quantity of electrodes but different placement. We imposed time dependent electric potential on different electrodes under the low Reynolds number condition, and then evaluated the impact of electrode position to the mixed results and summarized some rules which were conducive to achieving mixed. According to the simulation results and combined with the assembly process, we obtained the optimal number and placement of microelectrodes.

Abstract: The accelerometer is a sensitive inertial component of the inertial navigation system, and its output signal is proportional to the transporters acceleration. In system design and test, the dynamic characteristic of the closed-loop system is an important parameter. At present, the use of wire vibration or angular vibration to provide an input signal cannot meet the amplitude and phase of system testing requirements, and the test cost is high. Therefore, the study of how the dynamic characteristics of electrical simulation test system to give a precise mathematical accelerometer model is an important part of the analysis of the inertial navigation system,which is an effective method to acquire the dynamic characteristics and can be extended to mini inertia instruments. In this paper, we use the system identification method to identify the model of the system. Modeling of the system identification method is to determine the mathematical model of the system by observing the relationship between system inputs and outputs. The content of system identification generally includes four parts which are experimental design, model structure identification, parameter estimation and model test. Circuit simulation test of dynamic character of accelerometer system and model identification method have been applied in practical application. This paper has tested the accuracy of developed system designed by different system identifications.

Abstract: A new processing method, ultrasonic vibration assisted micro end grinding (UAMEG), is proposed to improve micro grinding technology, aiming at machining of brittle-rigid material micro components. Trajectories of adjacent two abrasive were modeled and simulated to perform kinematic investigation and mechanism analysis. The critical condition of regular high-frequency abrasive-workpiece separation (AWS) is obtained and proved to be: the frequency coefficient (K) is a positive integer. The effect of K is investigated. Cutting force and temperature reducing, smooth chip evacuation, tool life prolongation and machining accuracy improvement can be achieved in UAMEG from the kinematics point of view.