Pinhole size

S.F. Lim, L. Ke, W. Wang, and S.J. Chua, Correlation between dark spot growth and pinhole size in organic light-emitting diodes, Appl. Phys. Lett., 78 2116-2118, 2001. 

Upon shutdown, several bumplike deformations and pinhole-size leaks were observed in the upper region of the upper liner. Foster Wheeler believes these deformations were caused by the oxidation instability previously noted. The varying oxidation conditions below the injector result in changing heat flux to the neighboring liner, which in turn leads to thermal stresses and deformations. 

The several bumplike deformations and pinhole-size leaks observed in the upper region of the upper liner were attributed to the previously mentioned oxygen instability problem. The committee sees this discovery of deformations and tiny leaks as an issue, but not one so serious as to preclude implementation of the Foster Wheeler SCWO in a full-scale plant. 

Use of a confocal microscope (46) greatly improves Raman microspectroscopy. As shown in Fig. 3-12, confocal microscope has a pinhole (25 to 100 urn in diameter) which rejects out-of-focus signals. The smaller the pinhole size, the better the rejection. As a result, the background (substrate) signals can be... 

Sample Equal numbers of moles of He(g), O2(g), and C02(g) are placed in a glass vessel at room temperature. The vessel has a pinhole-sized leak, and the gases are allowed to effuse for a brief period of time. Rank order the gases remaining in the container, from the gas with the highest partial pressure to the gas with the lowest partial pressure. 

The Knudsen effusion technique entails heating a small quantity of the material under study in a refractory container, in a high vacuum, see the front cover of this book. Vapour effuses, through a small pinhole in the lid, and sprays on to a cold surface, where it condenses. After several hours, the deposit is weighed. Vapour pressures, such as those in Table 8.1, may then be calculated from the pinhole size, the deposition time, the weight deposited, and other constant factors. If the pinhole is sufficiently small, then equilibrium conditions may be assumed to prevail inside the cell. 

Various sections of the opened tubes were examined by optical techniques. Figure 5.35a shows the pitting pattern where several pinhole-sized pits are surrounding a large pit and areas of different colors. Species of different colors consisting of copper salts such as CuO/Cu(OH)2, CuCl2, and CU/Q12O were also present. 

The h value (in units of xm) depends on the pinhole size and the objective lens of the Raman microscope. This value can be... 

The thickness of the water layer over the electrode surface can also affect the vertical spatial resolution of the confocal system. For example, with smaller pinhole size (300 pm), the spatial resolution is about 17 pm and 19 pm, without and with the solution layer, while when the size is about 600 pm, the spatial resolution amounts to 21 and 53 pm for the surface without... 

The spatial filter may also be used to expand the beam (in order to vary the input beam diameter into the microscope objective, see Section 3.6). In a system where the pinhole size (PI) is matched to the lens (LI) spot size, then the ratio of the focal lengths of the collimating and focusing lenses give the factor of expansion. In our case the pinhole is smaller than the spot size. So the collimated beam diameter can be calculated, to an approximation, from equation 3.1 and in this case the collimated spatially filtered beam diameter is of the order 3-4 mm in diameter, which is smaller than the back aperture diameter of the microscope objective (around 5-6 mm). 

The cladding tubes contain the fission products released from the pellets. Ehiring the life of the fueL less than 0.5% of the tubes may develop pinhole-sized leaks through which some fission products escape. 

One way to measure the axial response of a confocal microscope is to record light intensity from a thin layer with infinite lateral extension. In a conventional microscope, no difference—and therefore no depth discrimination—are obtained. However, in confocal microscopy, a strong falloff occurs if the object is out of focus. The free width at half maximum (FWHM) of such a function is propoitional to the optical section thickness [64], [67]. The optical section thickness also depends on the diameter of the pinhole. The optimum pinhole size D with a maximum deterioration of 10% in reflection is given by [63]... 

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