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[13] [14] [5] The chemical enhancement of reactions by ultrasound has been explored and has beneficial applications in mixed phase synthesis, materials chemistry, and biomedical uses. Because cavitation can only occur in liquids, chemical reactions are not seen in the ultrasonic irradiation of solids or solid–gas systems.
High intensity ultrasound produces chemical and physical effects that can be used for the production or modification of a wide range of nanostructured materials. The principle that causes the modification of nanostructures in the sonochemical process is acoustic cavitation .
The reaction mechanism is described as follows: . With amines, the reaction proceeds without problems to the corresponding amides because amines are more nucleophilic.If the esterification is slow, a side-reaction occurs, diminishing the final yield or complicating purification of the product.
The major concern regarding ultrasound-enhanced chemiluminescence is the local heat generated by the ultrasound. Although the local heat could enhance the intensity and resolution of chemiluminescence images, producing heat beyond the endurance of cells can lead to tissue damage.
In organic chemistry, the Baylis–Hillman, Morita–Baylis–Hillman, or MBH reaction is a carbon-carbon bond-forming reaction between an activated alkene and a carbon electrophile in the presence of a nucleophilic catalyst, such as a tertiary amine or phosphine.
Resonant ultrasound spectroscopy (RUS) is a laboratory technique used in geology and material science to measure fundamental material properties involving elasticity. This technique relies on the fact that solid objects have natural frequencies at which they vibrate when mechanically excited.
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Contrast-enhanced ultrasound (CEUS) is the application of ultrasound contrast medium to traditional medical sonography. Ultrasound contrast agents rely on the different ways in which sound waves are reflected from interfaces between substances. This may be the surface of a small air bubble or a more complex structure.