Rules for the preparation of detail specifications for hermetically-sealed metal enclosed piezoelectric crystal filters of assessed quality, full assessment

2015 ◽  
Author(s):  
J.A. Eades ◽  
A. van Dun

The measurement of magnification in the electron microscope is always troublesome especially when a goniometer stage is in use, since there can be wide variations from calibrated values. One elegant method (L.M.Brown, private communication) of avoiding the difficulties of standard methods would be to fit a device which displaces the specimen a small but known distance and recording the displacement by a double exposure. Such a device would obviate the need for changing the specimen and guarantee that the magnification was measured under precisely the conditions used.Such a small displacement could be produced by any suitable transducer mounted in one of the specimen translation mechanisms. In the present case a piezoelectric crystal was used. Modern synthetic piezo electric ceramics readily give reproducible displacements in the right range for quite modest voltages (for example: Joyce and Wilson, 1969).


Author(s):  
S.A.C. Gould ◽  
B. Drake ◽  
C.B. Prater ◽  
A.L. Weisenhorn ◽  
S.M. Lindsay ◽  
...  

The atomic force microscope (AFM) is an instrument that can be used to image many samples of interest in biology and medicine. Images of polymerized amino acids, polyalanine and polyphenylalanine demonstrate the potential of the AFM for revealing the structure of molecules. Images of the protein fibrinogen which agree with TEM images demonstrate that the AFM can provide topographical data on larger molecules. Finally, images of DNA suggest the AFM may soon provide an easier and faster technique for DNA sequencing.The AFM consists of a microfabricated SiO2 triangular shaped cantilever with a diamond tip affixed at the elbow to act as a probe. The sample is mounted on a electronically driven piezoelectric crystal. It is then placed in contact with the tip and scanned. The topography of the surface causes minute deflections in the 100 μm long cantilever which are detected using an optical lever.


2013 ◽  
Vol 2013 ◽  
pp. 1-4 ◽  
Author(s):  
Caifeng Chen ◽  
Daiwei Hong ◽  
Andong Wang ◽  
Chaoying Ni

Flexible piezoelectric PZT/fabric composite material is pliable and tough in nature which is in a lack of traditional PZT patches. It has great application prospect in improving the sensitivity of sensor/actuator made by piezoelectric materials especially when they are used for curved surfaces or complicated conditions. In this paper, glass fiber cloth was adopted as carrier to grow PZT piezoelectric crystal particles by hydrothermal method, and the optimum conditions were studied. The results showed that the soft glass fiber cloth was an ideal kind of carrier. A large number of cubic-shaped PZT nanocrystallines grew firmly in the carrier with a dense and uniform distribution. The best hydrothermal condition was found to be pH 13, reaction time 24 h, and reaction temperature 200°C.


1990 ◽  
Vol 188 ◽  
Author(s):  
V. Gupta ◽  
A. S. Argon

ABSTRACTThe strength of planar interfaces between a substrate and a thin coating (1–2 µm) can be measured quite effectively by a laser spallation technique. In this technique a laser pulse of a high energy and a predetermined length is converted into a pressure pulse of a critical amplitude and width that is sent through the substrate toward the free surface with the coating. The compressive pressure pulse is reflected into a tension pulse from the free surface of the coating and loads the coating/substrate interface in tension. The laser flux is tuned to a threshold level at which the interface comes apart. The critical stress amplitude that accomplishes the removal of the coating is determined from a computer simulation process. The simulation itself is verified by means of a piezoelectric crystal probe which is capable of mapping out the profile of the stress pulse generated by the laser pulse.


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