High frequency techniques

In many cases, a comprehensive characterization of the rheological properties of systems, such as concentrated colloidal dispersions, can require measurements of dynamic mechanical behaviour at frequencies outside the range of conventional, commercially available, rheometers (typically 10 Hz to 10 Hz). In particular, consideration of the relative time scales of particle-fluid displacement and interfacial polarization mechanisms in such systems reveals the need for enhanced high frequency ranges (above ca. 10 Hz). 

High frequency rheometry, which usually involves wave propagation, offers some advantages over conventional techniques due to its inherent rapidity, and the (generally) small strains which are invoked. These are particularly useful features in the context of attempts to characterize the rheology of systems undergoing gelation whose non-equilibrium properties may involve pronoimced mechanical weakness and strain sensitivity. 

Inevitably, the conjunction of frequency-dependent visco-elastic properties and wave propagation leads to consideration of visco-elastic wave dispersion and its influence on conventional wave-based measurements, such as those involving resonance phenomena and pulse propagation techniques. 

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Ultrasonic Doppler velocimetry is a nonintrusive technique that has been developed into a very useful technique for opaque liquid flows [3]. This technique provides good measurement of velocity new high-frequency techniques give a space resolution on the millimeter level, and even the large turbulent scales can be resolved. 

Welding is easy using thermal processes, possible with ultrasound methods but impossible with the high-frequency technique. 

Polymethylpentenes have very weak loss factors, about 2 X 10 , and do not heat up under high-frequency current. They can be used for microwave ovenware but cannot be welded by the high-frequency technique. 

Welding is possible using thermal processes and by ultrasound but impossible by the high-frequency technique. 

Welding is easy by the thermal processes and possible with ultrasound but the high-frequency technique is unsuitable. 

The high-frequency technique used here for the first time was far superior to all other delousing methods known at that time. Not only did it kill the lice and their nits, it also destroyed the bacteria that caused spotted fever - as small-scale tests performed by the manufacturer showed. The facilities were developed by the firm Siemens-Schuckertwerke in Berlin preliminary tests were conducted in 1939. 

It appears that the subject grew out of an effort to produce broadband antennas for countermeasure purposes during World War II. The best, if not the first, treatment appears to be given in Very High-Frequency Techniques. If you find a copy, grab it [119]. 

Radio Research Laboratory, Very High-Frequency Techniques, Harvard University, Boston Technical Publishers, Boston, 1965. 

Sputtering is another technique sometimes used. Thin TaP films, for example, can be sputtered on to silicon nsing high-frequency techniques. Some metal phosphide films can be obtained by electrodeposition techniques (Section 12.7). 

Very High Frequency Techniques. Radio Research Laboratory, Harvard Univ. Press, Boston, MA. 

Sensorics High-frequency techniques Microelectronics Ultra-ftet optoelectronics... 

NEWTON - It is clear that you have accumulated a large body of data regarding the dependence of dielectric constant on ionic strength, a topic of great interest and past confusion. I take it that your high-frequency technique allows you to separate any extraneous dynamical effects (conductivity) from the desired screening part of the dielectric constant for electrolyte solutions. 

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