Double spread

When the boards are placed together in closed assemblies ready for clamping, the differences between single and double spread methods play a part in the nature of the adhesive bond. 

Glass drum Double spread method Phenol [469]... 

Spread (adhesive spread)—The quantity of adhesive per unit joint area applied to an adherend, usually expressed in points of adhesive per thousand square feet of joint area.(l) Single spread refers to the application of adhesive to only one adherend of a joint. (2) Double spread refers to application of adhesive to both adherends of a joint. 

Equation (2.28), being statistical in nature, requires a large number of particles to be measured, especially if the spread of particle size is wide. The possibility of error from this source is stressed by Arnell and Henneberry who found that in a particular sample of finely ground quartz, two particles in a total of 335 had a diameter about twenty times the most probable diameter, and that if these were overlooked the calculated value of A would be nearly doubled. 

The double-focusing combination of electrostatic- and magnetic-sector analyzers allows the inherent energy spread of the beam to be compensated for by design and ensures that there is no spread in the beam at the collector. 

Because there are two changes ia material composition near the active region, this represents a double heterojunction. Also shown ia Figure 12 is a stripe geometry that confines the current ia the direction parallel to the length of the junction. This further reduces the power threshold and makes the diffraction-limited spreading of the beam more symmetric. The stripe is often defined by implantation of protons, which reduces the electrical conductivity ia the implanted regions. Many different stmctures for semiconductor diode lasers have been developed. 

LB Films of Polymerizable Amphiphiles. Stxidies of LB films of polymerizable amphiphiles include simple olefinic amphiphiles, conjugated double bonds, dienes, and diacetylenes (4). In general, a monomeric ampbipbile can be spread and polymerization can be induced either at tbe air—water interface or after transfer to a soHd substrate. Tbe former polymerization results in a rigid layer tbat is difficult to transfer. 

So, nearly half a century after the emergence of the concept, we its practitioners have in materials science and engineering a clearly distinct discipline which in practice doubles up as a multidiscipline, with a substantial number of independent academic departments and research institutes spread around the world, with its own multifarious journals and textbooks, and a large number of professionals, also spread around the world, who call themselves materials scientists and engineers and communicate with each other on that basis. We have a profession to be proud of. 

The values in Table 2.4 show how resonance affects the strengths of bonds. For example, the strength of a carbon-carbon bond in benzene is intermediate between that of a single and that of a double bond. Resonance spreads multiple bond character over the bonds between atoms as a result, what were single bonds are strengthened and what were double bonds are weakened. The net effect overall is a stabilization of the molecule. 

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