Key Engineering Materials Vols. 645-646

Abstract: A micro attitude reference system is vulnerable to overload interference. To solve this problem, a type of Kalman filter was designed on the basis of a geomagnetic technique. Allan variance analysis was used to improve the Sage–Husa adaptive filter algorithm. Attitude error and gyro drifts were used as state variables for adaptive filtering updates, and a three-component magnetic vector was used for adaptive filtering measurement updates. Experimental results show that the pitch accuracy of the attitude reference system with magnetic filter technology working in 2 g vibrations improves by 4.7 times, the roll accuracy improves by 1.5 times, and the heading accuracy improves by 5.4 times. The proposed method can effectively reduce overload interference and ensure angular accuracy.

Abstract: A intelligent logistics monitoring microsystem has been designed based on STM32F103T8, which is high ability, low power consumption and low cost. The radio frequency (RF) chip CC1101, the acceleration sensor BMA280 and the temperature and humidity sensor HTU21D are selected to acquire the corresponding data for the intelligent logistics microsystem, which are ultra-low power consumption and ultra-small size. Moreover, in order to further reduce power consumption, the interrupt mode is adopted in the data acquisition module and the sleep mode is used in the MCU module in the software control. On the other hand, in order to further optimize the performance of miniaturization, the SWD (Serial Wire Debug) protocol is used. Meanwhile, the system will alarm the transportation officer once the acquired data met or exceed the threshold, which will help him to take corresponding measures timely, thus reducing the risk of occurrence effectively.

Abstract: The microstructure changes of acrylate spray-on waterproof material in alkaline groundwater environment were tentatively studied with X-ray microscopy (XRM), and the validity of deciding the failure of the material was explored in paper. Regarded NaOH solution with pH=12 as corrosive medium, after the immersion in the alkaline solution, spray-on waterproof material was scanned with XRM, and the structure was characterized with some indexes such as porosity and pore connectivity. The results show that when the waterproof material is immersed in alkaline solution for some time, the surface of the material becomes uneven, the overall porosity falls and the pore connectivity rises. It is feasible to study on the failure of waterproof material in underground engineering with XRM.

Abstract: This paper presents a precise angular algorithm for the imaging bionic polarization navigation sensor. The algorithm is targeted for a imaging sensor with bilayer nanowire polarizer which is multi-orientated of 0°, 60°, 120° and 90°, 150°, 210°. The algorithm is considered to extract intensity values of pixels in homogeneous regions, eliminate noise contained in image and compensate errors occured in the fabricaiton process of nanowire polarization filters. And the occlusion problem has to be compensated by neighboring pixels. The algorithm considered in this paper is able to solve overdetermined system of linear equations, and give a set of least square solutions of the Stokes parameters and the angle of polarization as output. The performance of the algorithm along with the experimental results of the angle measurement are also presented. Based on the comparison results, the algorithm achieves a best performance for the angle of polarization.

Abstract: A nanocantilever bending method is developed to investigate the interface cracking in multilayered nanoscale materials basing on the technology of the focused ion beam (FIB) and the transmission electron microscopy (TEM). With FIB, a nanocantilever specimen consisting of 20-nm-thick copper (Cu) layer and 500-nm-thick silicon nitride (SiN) layer on a silicon (Si) substrate is fabricated from a macroscale multi-layered material (Si/Cu/SiN) with the proposed method. By using a minute loading apparatus, the loading experiment is conducted in TEM, and the crack initiation at the edge of Cu/Si interface in different specimens is in situ observed. The critical stress fields at crack initiation are analyzed with the finite element method, and both normal and shear stresses concentrate at the region of 100 nm from the interface edge in all specimens. In addition, the normal stress is much larger than the shear one. A close observation on stress fields shows that the normal stress field at the area 20 nm–30 nm away from interface edge produces the local criterion for crack initiation at the edge of Cu/Si interface in nanoscale components.

Abstract: Understanding and measuring the displacement characteristics of piezoelectric ceramic with electric field exciting are particularly important. The piezoelectric coefficient d₃₃ as the indication of its displacement characteristics, is the key parameter of its energy transformation. In this paper, the characteristics of two kinds of piezoelectric ceramics, PZT4 and PZT5 were studied by the laser interferometer measurement. The influence factors of d₃₃ were studied, including the frequency and amplitude of the exciting signal, the ways of holding, and the loading sequence. Then the measurement results of piezoelectric ceramic with laser interferometer and the quasi-static method were compared, the results showed they had consistence and the analysis of the piezoelectric coefficient d₃₃ measurement by converse piezoelectric effect and by piezoelectric effect was discussed.

Abstract: MEMS nickel material is commonly used for structural material in micro devices. In order to study the effect of environmental temperature on its mechanical properties,this paper has built up a experimental system which can measure the temperature-related static mechanical parameters of the UV-LIGA nickel material. By using the system for uniaxial tensile experiments of the micro specimen under different temperature, the stress-strain curves of the micro specimen under different temperature were obtained; the mechanical parameters of the micro specimen such as elastic modulus, yield stress and failure stress under different temperature were also calculated out;Finally, the relationship between temperature and mechanical parameters including elastic modulus, yield stress and failure stress was analyzed.

Abstract: A novel vibration damping structure is designed based on the existing package structure of MEMS vector hydrophone. It is desirable that this novel structure can isolate the vibration noise caused by working platform so as to improve the anti-noise ability of hydrophone. This novel structure is made of “dow corning” damping silicone rubber which is manufactured with a certain proportion because of its small Young’s Modulus. The hydrophone is fabricated in the form of original packaging structure firstly and then in vibration-isolation packaging structure. Laboratory tests by means of the shaking table test and standing-wave tube test are performed to validate the theoretical results. The test results prove that the vibration damping structure can effectively isolate the interference signal produced by working platform without affecting the sensitivity of hydrophone obviously.

Abstract: Cloud forming by solid explosive dispersal plays a decisive factor for twice-detonating FAE. The study of the flow field of internal cloud field can be more intuitive to understand the whole process of the formation of cloud diffusion, and it also has an important role to the delay time setting of secondary detonating fuze. Internal parameters of spreading cloud are difficult to obtain even through by the experiment method, but numerical analysis and simulations method can get the parameter. In this paper, we use experimental and simulation methods to study fuel dispersal process, aims to establish an effective and reliable mathematical models of cloud dispersal, and get the model data coinciding with the real situation.

Abstract: This paper proposes a performance-enhanced SiOx/Al corrugated micro-cantilever structure, which transfers heat to mechanical deformation. Analytical simulations are carried out using the Finite Element Method (FEM), compared to the traditional straight bi-material structure (TSBMS) with same length L, the corrugated bi-material structures (CBMS) have higher temperature response sensitivity S_T and lower stiffness factor K. Furthermore, two types of cantilever was fabricated, and the test result verifies the change of the stiffness factor K. Finally, the thermal mechanical uncooled infrared focal plane array (FPA) with CBMS was fabricated, and the test results show that the bending response of the CBMS is about 2 times greater than TSBMS with same length. The CBMS proposed in this paper could be used widely in MEMS apparatus field based on bimaterial microcantilever.