MEMS压电超声换能器二维阵列的制备方法

针对超声换能器阵列中阵元密度难以提升和工艺重复性差等问题,提出了一种基于硅-硅键合技术的MEMS压电超声换能器二维阵列的制备方法,并采用该方法制备了阵元间距小至150μm的密排二维换能器阵列。阵列中每个声学单元均为由上电极、压电材料(PZT)层、下电极和支撑层组成的多层膜结构,并通过其弯曲振动模式实现超声波的发射和接收。制备样品的测试结果表明,采用该方法制作MEMS压电超声换能器阵列,具有阵元间距小、工艺流程可靠、成品率高、一致性好、工作频率(2.45MHz)与设计值(2.5MHz)的吻合度高等优点,适用于医学成像等高频超声成像系统。     

智能封堵器水上通信中单片机系统电路的设计

为了实现封堵器海洋工作环境中的无线遥控动作,封堵器在海底工作中采用了水声通信技术.文章首先介绍了水声通信系统的整体设计.在前期工作中,从影响水声通信的因素出发,对水声通讯频率的选择及水声换能器的选型进行了研究,确定了水声通讯的载波频率.在此基础上提出了基于单片机的水声Modem的制作方案,设计了单片机系统电路.并对单片...     

Differential Strain Gauge: A Sensor Device for Macro‐ and Microsystems

Abstract: The paper describes an operating principle for the electrical measurement of mechanical strain states. This principle gives up the idea of measuring the strain‐induced resistance change of single wire conductors and passes on to determining the strain‐induced deformation of the electrical field in area conductors. The basic operating principle, sensitivity considerations and the design of a functional prototype are described. Several experimental results in the application fields of transducer technology and strain analysis demonstrate the high capability of this method. The compact design allows simplification of the production process. An interesting additional advantage is the use of science‐based temperature compensation, i.e. the conventional, difficult process of foil treatment to attain temperature self‐compensation and suitability of each strain gauge for different component materials is superseded.     

Modelling of the Behaviour of Aramid Folded Cores Up to Global Crushing

Abstract: This study presents the basic ingredients needed to model the out‐of‐plane compression behaviour of a folded core up to the global peak load. This core is made of an aramid paper. The proposed approach is both experimental and numerical and handles the problem at different scales: fibre, paper and core scales. To have a good representation of the physics, two key points are essential. The first is the mechanical behaviour of the paper. The aramid paper can be modelled as a laminate composite. An experimental study of the paper behaviour in bending has been conducted to build a damage model for the paper. The second key point concerns the geometrical defects of the folded core. The defects, arising from the manufacturing process, are built by simulation of the folding process. The macroscopic behaviour of the core under out‐of‐plane compression loading is shown to be very sensitive to these defects. The results of a simulated crushing test are compared to experimental ones. A good agreement is shown.     

彩钢夹芯板房和帐篷的防火间距研究

对灾区过渡安置点搭设板房常用的彩钢聚苯乙烯(EPS)夹芯板和聚氨酯(PU)夹芯板结构、防火性能进行分析,同时对安置点内帐篷材质、燃烧性能进行介绍。在彩钢夹芯板房火灾实验基础上,用火灾案例和FDS模拟方法验证分析实验结论,研究确定彩钢夹芯板房和帐篷的防火间距。     

结构试验中二维位移检测技术探讨

结构试验中试件的位移主体大多发生在一个平面之内,而且位移量往往以一个方向的位移为主,与之垂直方向的位移为辅.传统位移检测方法中,需要用两只一维位移传感器组合的方式进行测试,但该方法在使用过程中有诸多弊端,如易发生测杆弯曲卡壳或基座松动,或对测点的位移敏感度低而达不到测试精度.本文提出一种结构试验中二维位移的测试方法,并...     

墙体保温技术的研究与发展(二)

(接上期) 3 新型墙体保温技术 3.1 UF-现浇泡沫墙体夹芯保温墙 UF-现浇泡沫夹芯保温墙体的保温材料是全水基发泡的环保型高效保温材料,由改性脲醛树脂和发泡液双组分液体经发泡、混合后喷出,固化形成的具有热绝缘性能的泡沫体[6].     

基于加速度检测的采煤机截割部异常冲击负荷检测装置

针对目前确定采煤机滚筒截割状态主要靠人工观察和手动动作调整的情况,基于MEMS双轴加速度传感器与单片机配合,研制了一种智能型异常冲击负荷检测装置。采用此检测装置能对采煤机摇臂滚筒的振动状态进行自动监测,采煤机主控系统及时采取保护动作,可避免异常截割引起破坏。该检测装置通过模拟振动试验,满足了设计要求。     

浅析现浇混凝土施工质量病害与控制措施

本文主要介绍了从混凝土的原材料、配合比、和易性以及施工过程中关键环节控制等方面分析影响混凝土施工质量的成因,并结合实际提出防治方法。     

聚氨酯硬泡夹芯轻质节能墙板抗风性能试验研究

通过聚氨酯硬泡夹芯轻质节能墙板抗风性能试验,揭示聚氨酯硬泡保温轻质墙板在水平风荷载作用下的受力性能、破坏特性,以供参考。