In the clinical use of ultrasound, transducers are always coupled to the skin by a thin layer at gel or oil, replacing the air that would otherwise exist between the transducer and the skin. (a) Using the values of acoustic impedance given in Table 17.5 calculate the intensity refiection coef?cient between transducer material and air. (b) Calculate the intensity refiection coefficient between transducer material and gel (assuming for this problem that its acoustic impedance is identical to that of water). (c) Based on the results at your calculations, explain why the gel is used.
In the clinical use of ultrasound, transducers are always coupled to the skin by a thin layer at gel or oil, replacing the air that would otherwise exist between the transducer and the skin. (a) Using the values of acoustic impedance given in Table 17.5 calculate the intensity refiection coef?cient between transducer material and air. (b) Calculate the intensity refiection coefficient between transducer material and gel (assuming for this problem that its acoustic impedance is identical to that of water). (c) Based on the results at your calculations, explain why the gel is used.
In the clinical use of ultrasound, transducers are always coupled to the skin by a thin layer at gel or oil, replacing the air that would otherwise exist between the transducer and the skin. (a) Using the values of acoustic impedance given in Table 17.5 calculate the intensity refiection coef?cient between transducer material and air. (b) Calculate the intensity refiection coefficient between transducer material and gel (assuming for this problem that its acoustic
impedance is identical to that of water). (c) Based on the results at your calculations, explain why the gel is used.
How can you tell which vowel is being produced here ( “ee,” “ah,” or “oo”)? Also, how would you be able to tell for the other vowels?
You want to fabricate a soft microfluidic chip like the one below. How would you go about
fabricating this chip knowing that you are targeting a channel with a square cross-sectional
profile of 200 μm by 200 μm. What materials and steps would you use and why? Disregard the
process to form the inlet and outlet.
Square Cross Section
1. What are the key steps involved in the fabrication of a semiconductor device.
2. You are hired by a chip manufacturing company, and you are asked to prepare a silicon wafer
with the pattern below. Describe the process you would use.
High Aspect
Ratio
Trenches
Undoped Si Wafer
P-doped Si
3. You would like to deposit material within a high aspect ratio trench. What approach would you
use and why?
4. A person is setting up a small clean room space to carry out an outreach activity to educate high
school students about patterning using photolithography. They obtained a positive photoresist, a
used spin coater, a high energy light lamp for exposure and ordered a plastic transparency mask
with a pattern on it to reduce cost. Upon trying this set up multiple times they find that the full
resist gets developed, and they are unable to transfer the pattern onto the resist. Help them
troubleshoot and find out why pattern of transfer has not been successful.
5. You are given a composite…
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