Micromachined high frequency PMN-PT/epoxy 1-3 composite ultrasonic annular array

This paper reports the design, fabrication, and performance of miniature micromachined high frequency PMN-PT/epoxy 1-3 composite ultrasonic annular arrays. The PMN-PT single crystal 1-3 composites were made with micromachining techniques. The area of a single crystal pillar was 9 × 9 μm. The width of the kerf among pillars was ∼5 μm and the kerfs were filled with a polymer. The composite thickness was 25 μm. A six-element annular transducer of equal element area of 0.2 mm² with 16 μm kerf widths between annuli was produced. The aperture size the array transducer is about 1.5 mm in diameter. A novel electrical interconnection strategy for high density array elements was implemented. After the transducer was attached to the electric connection board and packaged, the array transducer was tested in a pulse/echo arrangement, whereby the center frequency, bandwidth, two-way insertion loss (IL), and cross talk between adjacent elements were measured for each annulus. The center frequency was 50 MHz and −6 dB bandwidth was 90%. The average insertion loss was 19.5 dB at 50 MHz and the crosstalk between adjacent elements was about −35 dB. The micromachining techniques described in this paper are promising for the fabrication of other types of high frequency transducers, e.g. 1D and 2D arrays.     

超声检测用窄脉冲探头高阻抗背衬的研制

利用一种简单的压力装置，制作与PZT压电晶片匹配的背衬块，最高声阻抗可达25．1×106kg·m-2·s－1用于试制窄脉冲探头，可以实现1.5周期的脉冲．     

夹心式纵-扭复合模式压电超声换能器的共振频率

本文对夹心式纵－扭复合振动模式压电超声换能进行了研究，从换能器的等效电路出发，在无耦合时，得出换热能器纵向振动模式及扭转振动模式的各自共振频率方程，实验表明，换能器各自共振频率的测试值与理论计算值基本符合。     

The Transplant of Technology of Capacitive Displacement Transducer to Phase Modulation Grating-the Research of the Grating with nm Measuring Resolution

The method rising measuring resolution through reducing pitch of the transducer has brought forward from the basic structure, principle and the corresponding relationship among pitches of capacitive electrodes, period T and phase shift of o. But if the traditional technique of PCB made of the transducer is still used, it will meet with difficulties in lead wire. And so the technology transplant from the transducer to grating is presented, the basic principle of the phase modulation grating similar to the transducer is described and the experiments setup of transmitted and reflective grating are put out. Some practical schemes f the new grating with resolution to sub-micron, even nm is given.     

A simple device for checking the acoustic beam of ultrasonic therapy equipment

Ultrasound of time average acoustic intensities between 0.5 and 3 W cm⁻² is widely used in physiotherapy. A simple device for semiquantitative checking of output power and beam shape has been designed. The beam tester consists of an absorbing plate and a sheath liquid crystal thermometer for temperature distribution display.¹ The ultrasonic beam is fed to the absorber through a simple water tank.     

Measurements of Laser-Induced ShockPressures using PVDF Transducer

1.IntroductionThewideapplicationsoflaser-inducedshockwaveshadbeendeveloPed,forexam-ple,materialprocessing[1~'J,mediCaltreatment[4],measuring['J,etc.Alltheseinvesti-gationswerestronglyrelatedtotheprofi1eofpressurepulseinducedbythelaserradiationandthePeakpressureonthesurfaceoftargetmaterials.InthisP8Per,theshockpressuremeasurementshavebeenPerformedbyusingaNd-glasslaserwithapulsedurationof5onsasanexcitingbeamandaPVDFtransducerasadetector.2.ExPeriments2.lhoerAhighpowerNd-glass1aserisusedint…     

微重力燃烧实验落塔技术改进

上抛工作模式是一种有效的地基微重力实验技术．它能在基本上不增加落塔高度的情况下，成倍地增加微重力实验时间．本文将简要介绍在工程热物理所25米落塔设施上由实时过程控制技术和数控全速同步泛能换能技术组成的牵引式上抛技术的工作原理，基本组件，微重力状态下蜡烛火焰实验的初步结果，以及与NASA落塔和航天飞机实验结果的对比．     

医用梅花形超声探头声场的分析与计算

本文根据基尔霍夫积分．推导出了用于胎儿监护的梅花形超声多普勒探头声场的具体表达式．对中心大圆晶片发射、周围六个小圆片接收，以及七个相同晶片四发三收两种典型布局的换能器，其轴上声压分布，离辐射面不同距离断面上的声压分布及不同定向平面上的远场指向性进行了数值计算．结果表明，采用四发三收式结构较一发六收式结构具有较大的优越性．计算结果与实际测试结果很好地吻合．本项研究对此类探头的研制、使用及质量评价标准的制订，具有理论指导意义．     

光纤（光学）电流传感器的现状及发展

本文系统地评述光纤（光学）电流传感器研究的现状和存在的主要问题，给出不同调制方式的几种传感头的基本结构，分析比较它们的优缺点。针对影响传感器精度的因素，讨论目前采取的一些解决方法。文中指出光纤（光学）电流传感器的发展方向。     

Determination of phenytoin by modified extraction-gravimetry with a piezoelectric transducer

An extraction-frequencymetric method has been proposed for the determination of phenytoin sodium using a newly developed ring-coated piezoelectric crystal transducer. The sample solution is acidified with HCl and the liberated free phenytoin is extracted with 1,2-dichloroethane. The extract is applied to a ring-coated quartz crystal in nitrogen stream and after 2 min the crystal frequency is measured. The frequency change due to the deposited phenytoin is proportional to the phenytoin sodium content in the range 0.02–1.2 g. The method can be applied to the assay of phenytoin sodium tablets and injections.