Apparatus and method for improved acoustical transformation
A transducer and acoustic technology, applied in measurement devices, fluid analysis using sonic/ultrasonic/infrasonic waves, material analysis using sonic/ultrasonic/infrasonic waves, etc. Converter distance and other issues
Inactive Publication Date: 2015-07-15
VEECO INSTR
View PDF11 Cites 1 Cited by
- Summary
- Abstract
- Description
- Claims
- Application Information
AI Technical Summary
Problems solved by technology
[0006] However, while polyimide has reasonably high chemical resistance, it has been found that polyimide building blocks of acoustic transducers over time in metal-organic chemical vapor deposition (MOCVD) systems using InGaN becomes covered by gallium oxide and indium oxide; this accumulation is thought to cause drift in the sensor by reducing the distance between the transducers and affecting the transfer function of the acoustic transducer
It is also known that polyimides expand due to absorption of chemicals, which also reduces the distance between the individual transducers and affects the transfer function
Method used
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View moreImage
Smart Image Click on the blue labels to locate them in the text.
Smart ImageViewing Examples
Examples
Experimental program
Comparison scheme
Effect test
Embodiment Construction
[0051] refer to figure 1 , shows a timing diagram 20 of an acoustic chamber in one embodiment of the present invention. A pulse of acoustic energy 22 having a leading edge 24 and a trailing edge 26 in time is emitted by the transducer 28 and is coupled into the containing test medium 34 by the first acoustic transducer 36 having the low impedance layer 38 coupled to the protective shield 42 the test chamber 32. The first acoustic transducer 36 can be tailored to provide high efficiency energy transfer between the transducer 28 and the test medium 34 . The acoustic energy pulses 22 generated in this way constitute the transmitted signal S(t). The acoustic energy pulse 22 traverses the test chamber 32 through the test medium 34 and is incident on the opposite surface 46 of the test chamber 32 . figure 1 The time trace shown in shows the signal r' received by the opposite surface 46 and separated by the time interval Δt' 1 (t) and r' 2 (t).
[0052] In one embodiment, the...
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More PUM
| Property | Measurement | Unit |
|---|---|---|
| thickness | aaaaa | aaaaa |
| acoustic impedance | aaaaa | aaaaa |
Login to View More
Abstract
An acoustical transformer having a last matching section that includes a protective barrier of low permeability. The protective barrier is in contact with a test medium. In one embodiment, the protective barrier comprises one or more low permeability layers, such as a metallic foil or metallic coating(s) disposed on a low impedance layer such as polyimide, so that the low impedance layer and the protective barrier constitute the last matching section of the acoustical transformer. In other embodiments, the protective barrier comprises a fluoropolymer. A method for determining the thicknesses of the various layers of the acoustical transformer for enhanced performance is also disclosed.
Description
technical field [0001] The present disclosure relates generally to acoustic measurements performed in gases, liquids or solids, and more particularly to acoustic transducers used in acoustic measurements. Background technique [0002] Processes are employed in many industries that require accurate delivery of gas mixtures comprising specific gases dispersed in a carrier gas. Accurate delivery of such gas mixtures requires precise measurement of the concentration of specific gases in the flowing gas mixture, which are typically of high purity and can be highly corrosive. Examples of these processes include chemical vapor deposition (CVD), dopant diffusion (eg, as practiced in the semiconductor industry), and operation of high-efficiency hydrogen-cooled generators. [0003] One way to control the flux of a particular gas or reactant is to use a carrier gas, typically hydrogen and nitrogen, that flows through a gasifier or "bubble". The flow of carrier gas is controlled by a ...
Claims
the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More Application Information
Patent Timeline
Login to View More Patent Type & Authority Applications(China)
IPC IPC(8): G01N29/02G01N29/22
CPCG01N29/00G01N29/222G01N29/2437G10K11/02G01N29/036G01N2291/022G01N29/28
Inventor 雷蒙德·C·洛格唐·N·西戈塔威廉·E·奎因玛丽亚·D·费雷拉欧文·C·沃特金斯张伟
Owner VEECO INSTR