Butterfly vibration

In concluding this section it is important to point out that here we have only been able to discuss selected examples of what is known about the interactions of optically excited molecules in helium droplets. Finally, we would like to mention additional important results where exceptionally narrow widths of only 15 MHz (in the tunnelling transition of NHs), or very broad lines ( 10cm ) as in butterfly vibrations of pentacene in the Si excited state,or no relaxation as for the vibrationally excited HF molecule,have been observed. The wealth of new data on electronic spectroscopy in helium droplets is now beginning to yield insight into the mechanisms of the solvation of molecules in superfluid helium droplets. The quantitative understanding, however, still awaits ongoing and future research. 

We have to make a distinction here between electric controllers (e.g. PID controllers) with a proportional valve as actuator and mechanical diaphragm controllers. In a regulation system w/ith electric controllers the coordination between controller and actuator (piezoelectric gas inlet valve, inlet valve A/ith motor drive, butterfly control valve, throttle valve) is difficult because of the very different boundary conditions (volume of the vessel, effective pumping speed at the vessel, pressure control range). Such control circuits tend to vibrate easily when process malfunctions occur. It is virtually impossible to specify generally valid standard values. 

The most Raman-active intramolecular modes are the two modes (ag) encountered in the absorption spectra of Fig. 2.8 397 and 1404 cm-With a resolution of 1 cm- it is difficult to observe any splitting in these modes in addition, their frequencies show very little sensitivity to temperature. All these observations are in good agreement with the fact that the intramolecular modes are little affected by the crystal field. In contrast, the weakest vibrations (torsions, flexions, and internal distortions, such as butterfly and twisting motions) contribute significantly to the determination of the intermolecular modes, securing the thermalization of all the molecular degrees of freedom 45... 

Low-temperature Raman spectra of SCI2, SCI4, and S2CI2 have been reported [1775]. The 8214 ion assumes a butterfly structure of C2 (AsF6 salt) or C21 (SbF salt) symmetry, and the v(S-S) and v(I-I) vibrations are at 734 and 227 cm respectively. The IR/Raman spectra of the ion (X a halogen) containing the S7 ring are... 

Three v(M-N) bands are present in the spectra of butterfly ruthenium and osmium clusters. The highest frequency band, at about 860 cm , was assigned to the vibration along the wing-tip-nitride vector. The assignment of the other two bands is less straightforward, and the spectra have been re-interpreted. ... 

According to the theoretical study discussed above, the intense low frequency vibration around 250 cm is attributed to a long axis stretch of the whole molecule. The authors of [38] also studied the influence of various possible static distortions of the terrylene molecule on its vibrational structure. A boat or butterfly distortion about the short axis such that the planes of the terminal naphthalenes make a... 

Contact chemoreception of the dry plant surface is basically different from the well-studied perception of aqueous solutions. Since the stimulating compounds are in a dry state it may be that their distribution is not continuous and/or at a very low concentration. Thus not every contact between a sensillum tip and the plant would result in a stimulation. Although speculative, this may explain the specific behavior of various insect species after contacting plant leaves two female flies (P. rosae, D. brassicae) perform so called oviposition runs, on host leaves of about 20-30 s duration (Stadler, 1977,1978). Locusts make rapid vibrations (10-15 times per second) with the palps contacting the potential food plant surface. Blaney and Duckett (1975) showed that this palpation increases the amount of sensory input to the CNS by allowing disadap-tation of chemoreceptors between contacts. This must also be true for the tarsal hairs of two flies mentioned above. Some butterflies use the fore tarsi to drum or tap the plant surface prior to oviposition (Ma and Schoonhoven, 1973 ... 

There were no significant vibrations of the primary and secondary pipework. During the start-up period before the core was in place, butterfly valves in the primary circuits served as throttle valves. This induced some vibration in the adjacent down-stream line, but it was judged not to be relevant for operating conditions with the core installed. 

Moussou, R, Cambier, S., Lachene, D., Longarini, S., Paulhiac, L. Villouvier, V. 2001. Vibration investigation of a French PWR power plant piping system caused by cavitating butterfly valves. ASME-PUBLI-CATIONS-PVP 420,99 106. 

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