Dual frequency

Moholkar VS, Rekveld S, Warmoeskerken MMCG (2000) Modeling of the acoustic pressure fields and the distribution of the cavitation phenomena in a dual frequency sonic processor. Ultrasonics 38 666-670... 

Tatake PA, Pandit AB (2002) Modeling and experimental investigation into cavity dynamics and cavitational yield Influences of dual frequency ultrasound sources. Chem Eng Sci 57 4987 1995... 

Servant G, Laborde JL, Hita A, Caltagirone JP, Gerard A (2003) On the interaction between ultrasound waves and bubble clouds in mono and dual-frequency sonoreactors. Ultrason Sonochem 10 347-355... 

Sivakumar and Pandit [13] reported the use of hydrodynamic cavitation for decolorization of dye effluent stream. It has been observed that for same flow area, plate with larger number of small diameter holes gives higher extent of color removal as compared to the plate with smaller number of larger diameter holes. The observed results have been explained on the basis of frequency of turbulence for the two cases. The hydrodynamic cavitation reactor using multiple hole orifice plates has been found to give cavitational yields, which are two times higher than the best acoustic cavitation device (Dual frequency flow cell with capacity of 1.5 L). 

J. M. Schuchardt, J. A. Stratigos, J. A. Gagliano, D. O. Gallentine, J. L. King. Dual Frequency Multi-Channel Millimeter Wave Radiometers for High Altitude Observation of Atmospheric Water Vapor , 1979 MTT-S International Microwave Symposium Digest, pp. 540-542. 

Multidimensional and dual frequency infrared analogues of NMR Applications to peptides and isotopomers of secondary structures... 

D-IR SPECTROSCOPY WITH SINGLE AND DUAL FREQUENCY PULSES... 

Fig. 1. Time sequence of the three-pulse single- or dual-frequency (shaded and unshaded) heterodyned 2D-IR experiments. (A) Rephasing (B) Nonrephasing sequences. The signal is observed in the k2 +k3 -ki direction.

Fig. 2. Illustrations of three dual frequency 2D-IR experiments using one or two sets of OPAs and DFGs. (A) 3- and 6-pm with Febry-Perot interferometer filter (B) 6- and 7-pm (C) 3- and 6-pm.

The correlation of the vibrational frequency distributions of two modes can be determined from 2D-IR experiments and such effects are particularly evident in dual frequency experiments. For example, positive correlations between the amide-A and amide-I frequencies apparent from the spectra of acylalaninemethoxide (AcAlaOMe) in Figure 5, imply that when... 

Fig. 5. Dual-frequency (3-, 6-p.m) 2D-IR pump/probe of AcAlaOMe in chloroform acquired with magic angle polarization...

Fig. 6. Real parts of dual-frequency 2D-IR spectra ofNMA. (A) rephasing (B) nonrephasing.

Fig. 6.14. Label-free chemical imaging of the penetration pathways for the topically applied drug diffusion enhancer dimethyl sulfoxide (DMSO) into mouse skin tissue Dual-frequency SRS imaging tuned into the characteristic vibration of DMSO at 670 cm-1 (bright gray regions) and the CH2 vibration of lipid-rich adipocytes at 2845 cm-1 (dark gray regions) at a depth of 65pm into the tissue. DMSO is hydrophilic and hence avoids lipid structures such as adipocytes (Image courtesy of Brian Saar, Chris Freudiger, and Wei Min [12])...

Polymer Surface Modification by Dual-Frequency Plasma Treatment... 

These surface modifications were performed in "pure" micro-wave (2.45 GHz, "single-mode") or in combined microwave/ radio frequency (2.45 GHz/13.56 MHz, "dual-frequency") plasma. Important systematic changes of the surface composition, wettability, and adhesion of thin metal films were observed for different substrate bias values, and for the different gases. The modified surface-chemical structure is correlated with contact angle hysteresis of water drops this helps to identify which surface characteristics are connected with the wettability heterogeneity and with adhesive bonding properties, and how they are influenced by plasma-surface interactions. 

Fig. 1 Schematic arrangement of the dual frequency plasma system for surface treatment of polymers.

Fig. 3 Effect of substrate bias on the surface characteristics of PVC and PC treated by Ar in MW/RF "dual-frequency-mode" plasma.

The described dual-frequency plasma approach is very versatile and can be applied for deposition, etching, or surface modification merely by changing the operating parameters. This technology can readily be scaled up to large-area industrial requirements. 

Katoh [1] prepared a liquid crystal composition for use as electronic paper consisting of one dual-frequency switchable smectic liquid crystal, (1), and at least one dichroic dye. 

Edvardsson, M., Rodahl, M., Kasemo, B., and H66k, F. (2005). A dual-frequency QCM-D setup operating at elevated oscillation amplitudes. Anal. Chem., 77, 4918-4926. 

Glover D. M., Frew N. M., McCue S. J., and BockE. J. (2002) A multi-year rime series of global gas transfer velocity from the TOPEX dual frequency, normalised radar backscatter algorithm. In Gas Transfer at Water Surfaces, Geophysical Monographs (eds. M. A. Donelan, W. M. Drennan, E. S. Saltzman, and R. Wanninkhof). AGU, Washington, DC, vol. 127, pp. 325-333. 

Fiorini, C., Charra, F., Nunzi, J.-M., and Raimond, P. (1997). Quasi-permament all-optical encoding of noncentrosymmetry in azo-dye polymers./. Opt. Soc. Am. B 14, 1984-2003. Fiorini, C., Charra, E, Etile, A.-C., Raimond, R, and Nunzi, J.-M. (2000). Photoinduced non-centrosymmetry in azo-polymers using dual frequency interferences. In Advanced functional molecules and polymers (H. S. Nalwa, ed.), pp. 167-216, Gordon and Breach Science Publishers, Amsterdam. 

Enlc, A.-C., Fiorini, C., Charra, E, and Nunzi, J.-M. (1997). Phase-coherent control of the molecular polar order in polymers using dual-frequency interferences between circularly polarized beams. Phys. Rev. A 56, 3888-3896. 

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