Narrow slits

Figure 3.4 (a) Diffraction pattern produced by a narrow slit, (b) The Rayleigh criterion for... 

In Section 2.3.5.1 we have seen that pumping of atoms or molecules through a narrow slit, or small pinhole, whose width (or diameter) is about 20 pm at a pressure of a few torr on the high-pressure side of the aperture produces an efllisive beam. Removal of pressure... 

Derive a similar expression for correcting apparent shear rates at the walls of a die whose cross-section is in the form of a very long narrow slit. 

B. Gotzelmann, S. Dietrich. Density profiles and pair correlation functions of hard spheres in narrow slits. Phys Rev E 55 2993-3005, 1997. 

R. Kjellander, S. Sarman. A study of anisotropic pair distribution theories for Lennard-Jones fluids in narrow slits. II. Pair correlations and solvation forces. Mol Phys 74 665-688, 1991. 

S. Sarman. The influence of the fluid-wall interaction potential on the structure of a simple fluid in a narrow slit. J Chem Phys 92 4447—4455, 1990. 

Single chains confined between two parallel purely repulsive walls with = 0 show in the simulations the crossover from three- to two-dimensional behavior more clearly than in the case of adsorption (Sec. Ill), where we saw that the scaling exponents for the diffusion constant and the relaxation time slightly exceeded their theoretical values of 1 and 2.5, respectively. In sufficiently narrow slits, D density profile in the perpendicular direction (z) across the film that the monomers are localized in the mid-plane z = Djl so that a two-dimensional SAW, cf. Eq. (24), is easily established [15] i.e., the scaling of the longitudinal component of the mean gyration radius and also the relaxation times exhibit nicely the 2 /-exponent = 3/4 (Fig. 13). 

Travis, K. P., Gubbins, K. E., Poiseuille flow of Lennard-Jones fluids in narrow slit pores, J. Chem. Phys. 112, 4 (2000) 1984-1994. 

Generally in solution at room temperature only fluorescence emission is observed. To obtain phosphorescence spectra, low temperatures are used and a rotating can with a narrow slit in the side is placed around the sample. Since the lifetime of the fluorescent state is generally much shorter than that of the phosphorescent state, the time required for the slit in the can to rotate 90° ensures that only the longer lived phosphorescence will be observed. 

Figure 2.21. A, High-intensity point source lamp B, parabolic mirror C, light baffle D, narrow slit E, collimating lens F, Coming filters G, reaction cell or series of cells H, focusing lens I, photomultiplier.

The mass-transfer correlation obtained by Bohm et al. (B9), Eq. (33), in Table VII, is conspicuous for its remarkably high exponent (0.85) on the GrSc product. Since the current is almost independent of diffusivity, this must mean that the reacting ion is depleted at the downstream end of the narrow slit between the cathode and diaphragm. The total current then is determined largely by the convective transport of reactant into the slit, which, in turn, depends on the density difference but not on diffusivity. 

Figure 3.1 (a) Schematic diagram (not to scale) of Young s double-slit experiment. The narrow slits acts as wave sources. Slits S and S2 behave as coherent sources that produce an interference pattern on screen C. (b) The fringe pattern formed on screen C could look like this. (Reproduced with permission from R. A. Serway Physics for Scientists and Engineers with Modern Physics, 3rd ed, 1990, Saunders, Figure 37.1.)... 

The moving slit device is designed to directly measure the primary beam intensity without overloading the detector. It works like a slit shutter of a photographic camera a narrow slit is moved along the primary beam. If a sample is in the beam, the absorption of the primary beam by the sample can be directly measured. 

A narrow slit in the tread pattern of a pneumatic tyre, formed by fitting a thin blade in the mould often termed knife-cut . 

A 500 kW fire in a compartment causes the smoke layer to reach an average temperature of 400 °C. The ambient temperature is 20 °C. Air and hot gas flow through a doorway at which the neutral plane is observed to be 1 m above the floor. A narrow slit 1 cm high and 3 m wide is nominally 2 m above the floor. 

The method used by the group was first to determine the direction of substrate tilt by means of reciprocal space maps in each of the <110> directions contained in the plane of the wafer. These are shown in Figure 7.14. A narrow slit was used instead of an analyser ciystal, so some analyser streaks are seen near the substrate peaks (on the right of each map— the origin in this case is on the left-hand sides). It is seen that in (a) and (b) the beam is oriented perpendicular to the substrate tilt axis, as these maps show only strain. In (c) and (d) the effect of the grading can be seen, since both the tilt and the strain are changing, but these views are insufficient to make a complete analysis. For this we need an... 

General Description of Method.— The gas is ionized by impact electrons emitted by a hot tungsten filament, and, by means of an electric field the positive ions formed are drawn through a narrow slit into a magnetic field, where they are resolved into constituents of different ratios of charge to mass by a method very similar to that employed by Dempster in his positive ray analysis. The ionization potential necessary to produce each ion is determined by gradually reducing the potential applied to the impact electrons until no trace of the particular ion can be detected. 

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