http://www.k-wave.org/forum/topic/simulation-in-different-absorption-temperature-transducer-cases Support for the k-Wave MATLAB toolbox en-US Tue, 12 May 2026 23:05:38 +0000 http://bbpress.org/?v=1.0.2 q http://www.k-wave.org/forum/search.php http://www.k-wave.org/forum/topic/simulation-in-different-absorption-temperature-transducer-cases#post-235 Mon, 19 Sep 2011 12:48:34 +0000 ChiaChin Li 235@http://www.k-wave.org/forum/ <p>Hi Ben,</p> <p>I repeat my simulation without speed change. And all the slopes were the same in different absorption and frequency response of US transducers used for detection. The sound speed as a temperature function is:</p> <p>speed = 1.40238742e3 +T_current*5.03821344 -T_current^2*5.80539349e-2 +T_current^3*3.32000870e-4 -T_current^4*1.445379e-6 +T_current^5*2.99408365e-9; %[m/s]</p> <p>(from: <a href="http://resource.npl.co.uk/acoustics/techguides/soundpurewater/content.html#BILANIUK" rel="nofollow">http://resource.npl.co.uk/acoustics/techguides/soundpurewater/content.html#BILANIUK</a> )</p> <p>And it seems like that the dispersion associated with the absorption will not effect the slopes. But from the equation of PA signal generation, the peak value of detected PA signal should not change with different sound velocities. What information of my simulation should I offer to you to solve my problem?</p> <p>Thanks for your help!</p> <p>Chia-Chin </p> http://www.k-wave.org/forum/topic/simulation-in-different-absorption-temperature-transducer-cases#post-228 Wed, 07 Sep 2011 17:41:26 +0000 bencox 228@http://www.k-wave.org/forum/ <p>Dear Chia-Chin,</p> <p>Apologies for the delay in replying, we've both been away.</p> <p>The graphs of the slope vs centre frequency don't seem to agree with the previous graphs showing the amplitude changes as a function of temperature. Are they from the same data set?</p> <p>There are a couple of things we can think of straight off:</p> <p>Do you still see the change in the slopes when you don't include the sound speed change with temperature? Is it just a function of the temperature dependence of the sound speed?</p> <p>There will be some dispersion associated with the absorption which may change the shape of the pulse a bit (although this may not be a large effect).</p> <p>Ben </p> http://www.k-wave.org/forum/topic/simulation-in-different-absorption-temperature-transducer-cases#post-224 Tue, 23 Aug 2011 10:19:29 +0000 ChiaChin Li 224@http://www.k-wave.org/forum/ <p>Hi,</p> <p>According to Photoacoustic signal generation,<br /> P_initial = (Pulse laser energy)*(absorption coef.)*(Grueneisen coef.)<br /> I assume that pulsed laser energy and absorption coefficient are independent with Temperature. And Grueneisen coefficient is direct proportion with temperature.<br /> So I expect that I can simulate the result of PA signal peak values raise with temperature in direct proportion.</p> <p>I wanted to simulate PA signal changes in different cases of temperature(25-55 degree C: raising value of initial pressure and sound speed with temperature), absorption(25,50,83.33,250,500 cm^(-1): size of initial pressure spot), and ultrasound transducer(fc=5,10,25,50MHz) used for signal detection.</p> <p>The signal flow of my 1D simulation:<br /> <a href="http://imgur.com/Yoe34" rel="nofollow">http://imgur.com/Yoe34</a></p> <p>And the 1D simulated result in different absorption at 25 degree C:<br /> <a href="http://imgur.com/IW0SF" rel="nofollow">http://imgur.com/IW0SF</a></p> <p>Then I record the peak value of PA signals from 25 to 55 degree C, and make the PA signal changes as a function of temperature:<br /> <a href="http://imgur.com/v9p1B" rel="nofollow">http://imgur.com/v9p1B</a></p> <p>But the slope of PA signal and temperature as a function of center frequency showed strange tendency:<br /> <a href="http://imgur.com/XdqsC" rel="nofollow">http://imgur.com/XdqsC</a></p> <p>I thought the result in final picture(http://imgur.com/XdqsC) should be constant of center frequency. But it shows surprising result. Did I do any wrong settings? Could you help me solve my problem?</p> <p>Thanks a lot.</p> <p>Chia-Chin </p>