Differential contraction

Assuming, for example, that there is differential contraction in the film and substrate (Figure Ic). The film, now detached from the substrate, is still free of stress. 

Figure 8.21 shows a composite truncated spectrum of boron in a silicon sample in which a stress along < 111 > is produced by differential contraction between the sample and the copper jig. Because of the relatively low resolution used in this study, only lines 4 and 4A/6 were resolved and line 4B/5 was not considered (it was in 1967), but this figure gives none the less a very good global idea of the stress splitting of acceptors at low stress in silicon. A comparison can be made with the zero stress p3/2 spectrum of Fig. 7.1. 

Recent investigations of surface properties of materials have revealed that many covalent (e.g. Si), ionic (e.g. LiF) and metallic (e.g. Pt) materials undergo crystallographic changes at the surface. The electronic structure near the surface is correspondingly modified (66,67) relative to that of the bulk. Ionic compounds with NaCl-structure have long been known to undergo a so-called surface relaxation 68, 69). This is a differential contraction (relaxation) of the surface cation (anion) lattice constant. 

This constant-strain apparatus was constructed in a manner similar to that described by Telinde [ ]. To minimize differential contraction effects, the aluminum beam and the side supports were all cut from the same 2024-T3 aluminum plate with the same orientation. The fixture is shown disassembled in Fig. 6 and assembled in Fig. 7. 

To support the deployment of fiber networks in very cold environments (—55 to —60°C), modifications of standard cable designs are typically needed to improve their low temperature performance. The primary concern is protecting the fibers fi om stresses induced by the differential contraction of the various cable materials at low temperature extremes. This is usually best achieved by optimizing the basic stranded core concept to isolate the fibers, while allowing for the differential expansion and contraction forces. Since these cables are otherwise not distinctly different from standard stranded loose-tube designs representative cross-sectional pictures are not included. 

Thus bending can occur due to differential contraction and expansion of outer most remote fibers of a strip if an electric field is imposed across its thickness as shown below in Figures 1 and 2. Numerical solutions to the above set of dynamic equations are presently underway and will be reported later. However, it must be mentioned that the governing equations (IH ) Asplay a set of highly non-linear dynamic equations of motion for the IPMC artificial muscles. 

The cooling rate at the tail end of the process is as important as at the onset of heating. Extreme cooling rates may result in component cracking or electrical performance degradation induced by differential contraction of materials. 

The change in performance of both channels is likely due to the differential contractions and expansions of the screen wires after being exposed to multiple thermal cycles during LH2 testing. The reduction in performance could also be due to defects at the Ni/SS interface at the screen/plate interface. It is fairly certain that degradation in bubble point occurred after LH2 tests, and not before, since both channels performed relatively similar at similar LH2 test conditions as will be shown, and because experimental performance compared well with model predictions. 

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