Impingement frequency

Hence the number of molecules hitting the surface per unit time per unit area is a flux. Also, it is proportional to the pressure of the gas and the mean speed of the gas molecules and to T 2. At room temperature and pressure the impingement frequency of nitrogen is ... 

In this chapter, method for preparing high-quality boron films by pyrolysis of decaborane in the molecular flow region at temperatures between 350 and 1200°C is described. The deposition mechanism is discussed in terms of the dependence of the deposition rate on the substrate temperature and the impingement frequency of decaborane molecules onto the substrate surface. 

It is thought that the deposition rate of boron films obtained by pyrolysis of decaborane depends on the impingement frequency of decaborane on the substrate. From gaseous molecular dynamics, the impingement frequency S of decaborane on the substrate surface is given by... 

The rate of chemisorption depends on the impingement frequency S of the decaborane molecules on the surface, the condensation coefficient y, and the fraction of collisions that take place at available sites/(0), where 0 is the fractional surface coverage. The rate of chemisorption, U is given by... 

As shown in Fig. 5, the deposition rate is independent of temperature, and the chemisorption is nonactivated hence, the activation energy E = 0. Under the experimental conditions, we suppose that/(0) = 1 and y % 1 hence, the rate of chemisorption is equal to the impingement frequency S. The theoretical deposition rate 0 in this high temperature range is... 

Amorphous boron films have been deposited by pyrolysis of decaborane in the molecular flow region. On the assumption that the deposition rate of boron Aims is determined by the impingement frequency of the decaborane molecules onto the substrate surface, we have derived an equation for the deposition rate D at temperatures lower than 416°C. The equation, D = 7.16 X lO P exp(-39,000 / fs)(cm/s), explains the experimental results successfully. 

Reduce Resonant Vibration. Metal stmctures are induced to vibrate at their natural frequencies when driven mechanically by attachment to some other vibrating stmcture, by impact of solid objects, or by turbulent impingement of a fluid (including air). Examples are stainless steel sinks driven... 

Nuclear magnetic resonance (nmr) requires an atomic nuclei that can absorb a radio-frequency signal impinging it in a strong magnetic field to give a spectmm. The field strength at which the nucleus absorbs is a function of both the nucleus and its immediate electronic environment. The atoms normally used for nmr analysis are as follows (34) H, F, P, Si, and Of these, the most commonly used in polymer analyses are... 

The vibrational motions of the chemically bound constituents of matter have fre-quencies in the infrared regime. The oscillations induced by certain vibrational modes provide a means for matter to couple with an impinging beam of infrared electromagnetic radiation and to exchange energy with it when the frequencies are in resonance. In the infrared experiment, the intensity of a beam of infrared radiation is measured before (Iq) and after (7) it interacts with the sample as a function of light frequency, w[. A plot of I/Iq versus frequency is the infrared spectrum. The identities, surrounding environments, and concentrations of the chemical bonds that are present can be determined. 

A high-frequency pressure wave is transmitted at an acute angle to the walls of the pipe and impinges on a receiver on the other side of the pipe. The elapsed time between... 

How useful is the rate expression derived from collision theory for describing adsorption For cases in which adsorption is not activated, i.e. E = 0, the collision frequency describes, in essence, the rate of impingement of a gas on a surface. This is an upper limit for the rate of adsorption. In general, the rate of adsorption is lower, because the molecules must, for example, interact inelastically with the sur-... 

A light pulse of a center frequency Q impinges on an interface. Raman-active modes of nuclear motion are coherently excited via impulsive stimulated Raman scattering, when the time width of the pulse is shorter than the period of the vibration. The ultrashort light pulse has a finite frequency width related to the Fourier transformation of the time width, according to the energy-time uncertainty relation. 

A possible explanation for the difference in tendencies of the deposition rate between experiment and model is that in the model the surface reaction and sticking coefficients of the radicals are taken to be independent of the discharge characteristics. In fact, these surface reaction coefficients may be influenced by the ions impinging on the surface [251]. An impinging ion may create an active site (or dangling bond) at the surface, which enhances the sticking coefficient. Recent experiments by Hamers et al. [163] corroborate this the ion flux increases with the RF frequency. However, Sansonnens et al. [252] show that the increase of deposition rate cannot be explained by the influence of ions only. 

Hair cells are the sensory cells of the auditory and vestibular systems. Hair cells are the sensory cells of the internal ear, essential for the senses of sound and balance. The hair cell s transduction apparatus, the molecular machinery that converts forces and displacements into electrical responses, can respond to mechanical stimuli of less than 1 nm in amplitude, and of tens or even hundreds of kilohertz in frequency. Indeed, our hearing is ultimately limited by Brownian motion of water molecules impinging on the transduction apparatus. 

Locally invasive prostate cancer is associated with ureteral dysfunction or impingement, such as alterations in micturition (e.g., urinary frequency, hesitancy, dribbling). 

Light impinging on the surface of the Mediterranean Sea is scattered. Of this light, a small proportion is scattered in such a way that the frequency changes, causing it to look more blue than was the incident light. This shift in frequency causes the blue colour of the Mediterranean Sea. 

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