Ultrasound devices

Commercial ultrasound devices for high-throughput analysis... 

In relation to applioation duration, most ultrasonio instruments utilize either pulsed (tone-burst or broad-band pulses) or continuous-wave US (Fig. 9.4). Ultrasound pulses are by far the most widely used choice as pulses are easily applied, measurements are rapid and non-invasive, and the ultrasound device can be readily automated. Continuous-wave teohniques have been traditionally used for highly aoourate measurements in speoialized research laboratories. 

An ultrasound device is a diagnostic tool that allows doctors to see inside the human body without having to perform surgery. With an ultrasound device, doctors can detect ahnormal growths, follow the development of a fetus in the uterus, or study the action of heart valves. 

An ultrasound device emits high-frequency sound waves that can pass through a material, he absorbed, or reflect off the surface of a material. Waves are reflected at the border between tissues with different densities, such as an organ and a tumor. The larger the difference in density, the greater the reflection. 

L-selectin ligand-specific USCA could be a candidate for an indirect method of lymphography for the safe and less-invasive ultrasonic identification of lymph nodes, e.g., when performing a biopsy. Lymph node-targeted microbubbles can be detected easily with any ultrasound device that has color Doppler capabilities. 

Figure 2.28. Rearrangement of microwave oven with ultrasound device.

The determination of local intensities is quite difficult, and ultrasound devices are mostly characterized by calorimetric measurements. Sound-pressure measurements and methods for determining the local intensity with coated thermocouples or by chemical means are still under development. 

It might be expected that improved ultrasound technology and less expensive ultrasound devices will help to spread the use of this technology and to reduce expensive and unnecessary CT and MRI examinations. The use of contrast agents opens totally new prospects within the foreseeable future, on the one hand, and represents a challenge for every sonographer, on the other. 

Piezoelectrics Pb(Zr,Ti)03, (PZT), PbTiOs, PbBi2Nb209 Bi4Ti30]2 Transducers, ultrasound devices sensors... 

Emulsions are ubiquitous in consumer applications, including pharmaceuticals, food products, adhesives and personal care products. Product characteristics are influenced both by the chemical formulation and by the processing technology employed. Traditionally, emulsions are formed under high shear conditions using static mixers, ultrasound devices, homogenizers or rotor/stator mixers. Compositions and process conditions are often over-designed to ensure that product requirements are met [2]. 

The efficiency of the extraction methods in acid-aqueous media (0.1 M HCl, or 0.1 M HCl-methanol) or in chloroform solution (for pre-alkaline samples) was investigated. Various devices (ultrasound device, shaking machine, Soxhlet-apparatus) were used for the extraction. The best method was the extraction with 0.1 M HCl- methanol (1 1, v/v) in ultrasound device. 

The initial efforts in PVDF hydrophone development in the 1970s were motivated by the lack of a broadband sensor to measure the pulsed pressure fields produced by diagnostic ultrasound devices. The piezoelectric ceramic hydrophones available at the time were suitable for characterizing the continuous-wave and narrow band tone-burst pressures... 

The discovery of strong piezoelectricity in PVDF has led to the development of numerous polymer based acoustic sensors, in particular the spot poled membrane hydrophone design in its various embodiments. These hydrophones have become the primary devices for characterizing biomedical ultrasound fields. Their development has made possible the quantification of medical ultrasound exposure levels, and so enabled standards organizations to adopt a rational and systematic approach to address the problems of field measurements and device safety. Significant measurement challenges remain, particularly in the area of therapeutic ultrasound, but it is clear that PVDF will continue to play a pivotal role in the characterization of medical ultrasound devices. 

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