一种具有自检功能的压电角速率陀螺

介绍了一种具有自我检测功能的压电角速率陀螺以及基本原理和实验结果。

新型压电陶瓷角扫描器(PZTA)

本文介绍了一种全新结构的压电角扫描器ＰＺＴＡ，在对ＰＺＴ材料压电变形研究的基础上，开展了用逆压电效应进行大角度可控光扫描的探索性工作，并成功实现了可用于低温扫描的压电角扫描器。

YT－1型压电陀螺钻孔测斜仪的研制和发展前景

ＹＴ－１型压电陀螺钻孔测斜仪是国内外首次采用压电角速率陀螺作测量钻孔方位的主件的。研制了一套与其定向特性相适应的地面定向、电子跟踪测量等新的定向方法系统。该仪器与传统机械陀螺钻孔测斜仪相比具有很多优点。实测应用效果好，经改进后仪器将有较广泛的发展和应用前景，具有很好的社会和经济效益。

Experimental investigation on mechanical behaviors of granites after high-temperature exposure

To investigate the influence of temperature on the physical,mechanical and acoustic emission characteristics of granites,uniaxial compression test,variable-angle shear test,acoustic emission signal monitoring and the measurement of physical parameters including mass,size and P-wave velocity were carried out on granite samples treated at temperatures T ranging from 25 to 900℃.The results show that the density and P-wave velocity decrease gradually with increasing T.As the temperature increases,the peak compressive stress decreases while the peak strain increases,due to the fact that a high temperature induces the escaping of waters within granites,the expanding of mineral grains and the generations of fractures.With the increment of T,both the peak shear stress and the cohesion decrease,whereas the frictional angle increases.During the compressing and shearing tests,the maximum acoustic emission counts show a decreasing trend when T increases from 25 to 900℃.When T exceeds 573℃,the crystal lattice structure of quartz changes fromα-phase toβ-phase,decreasing the mechanical behavior of granites to a great extent.In addition,the results also indicate that T=500−600℃ is the critical temperature ramge to characterize the influence of temperature on the physical,mechanical and acoustic emission characteristics of granites.

Theory and experimental verification of valveless piezoelectric pump with rotatable unsymmetrical slopes

A valveless piezoelectric pump with rotatable unsymmetrical slopes is developed in this research.It has the following features:The pump integrates driving and transporting,and it can mix different fluids while transporting them.In this paper,firstly,the design of the valveless piezoelectric pump with rotatable unsymmetrical slopes was proposed,and the single-direction flow principle was explained.Then,the fluid mechanics model of the valveless piezoelectric pump with rotatable unsymmetrical slopes was established.Meanwhile,the numerical simulation of the pump was performed.Finally,the experiments on relationship between the rotation angles of the slope and the flow rates were conducted.The experimental results showed that the maximum flow was 32.32 mL min 1.The maximum relative error between the theoretical results and the experimental ones was 14.59%.For the relationship between rotation angles and flow ratio of two inlets,the relative error between the experimental and theoretical maxima was 3.75%.Thus,the experiments proved the feasibility of the pump design and verified the theory.

Piezoelectric active control for tail buffeting at high angle of attack

Tail buffeting at high angle of attack causes distinct fatigue problem on tail structure of twin tail fighters.In this study,a piezoelectric active control experiment of tail buffeting was performed in a wind tunnel using arching PZT actuator(APA) and principal modal control(PMC) method.Test results showed the peak value of power spectral density(PSD) function of tail buffeting acceleration response could be suppressed by about 42% when the angle of attack reached 35°,indicating the validity and feasibility of PMC method and APA for tail buffeting alleviation at high angle of attack.

Angular tuning of defect modes spectra for one dimensional photonic crystal filters with a liquid crystal layer

A tunable photonic crystal filter with a twisted nematic liquid crystal layer is proposed. The defect modes spectra with varying incident angles are discussed in detail by 4×4 matrix method. The results show that the defect modes are mainly decided by the applied voltage when the incident angle is smaller than 8°. As the incident angle further increases, the band gap and the defect modes shift toward the shorter wavelength side, and the changes of the two modes are different, In the lower voltage range, the defect modes can be tuned not only by the applied voltage but also by the incident angle. In the higher voltage range, the defect modes can be further tuned by varying incident angle and the different modes can be separated from each other by a bip incident anple.