Compositional modulation

A second application of current interest in which widely separated length scales come into play is fabrication of modulated foils or wires with layer thickness of a few nanometers or less [156]. In this application, the aspect ratio of layer thickness, which may be of nearly atomic dimensions, to workpiece size, is enormous, and the current distribution must be uniform on the entire range of scales between the two. Optimal conditions for these structures require control by local mechanisms to suppress instability and produce layer by layer growth. Epitaxially deposited single crystals with modulated composition on these scales can be described as superlattices. Moffat, in a report on Cu-Ni superlattices, briefly reviews the constraints operating on their fabrication by electrodeposition [157]. 

The two PIPs constitute an offset modulated composite pulse for use with a 900 MHz NMR instrument. As a result, the centre of 13C is subjected to two consecutive 2ir rotations of opposite offsets, one positive and the other negative, but of the same (x) phases in the two different Eigenframes as shown in Fig. 23. In the vicinity of the centre of the 13C , the sum of the two rotation angles can be expressed as... 

Fet us now consider an initial composition C2. We are within the two spinodal points on the Gibbs free energy coherent curve G decomposition takes place spontaneously throughout the entire phase, with modulated compositional fluctuations whose amphtudes increase as the process advances. We always obtain pigeonite plus diopside, although theoretically the orthopyroxene plus diopside paragenesis, also in this case, corresponds to the minimum energy of the system. 

Mechanical engineers have used polarized light to detect stress patterns for many years and more recently a number of workers [3-6] have explored the possibilities of photoelasticity for the fabrication of polarization modulators. The systems have been given several names, photoacoustic modulators, photoelastic modulators and stress modulators, the term photoelastic modulator will be used in this chapter. There are basically two types of photoelastic modulator, composite resonators and matched element resonators. Diagrams of the composite resonator and matched element resonator are shown in figures 6 and 7 respectively. The original piezo-optical devices [7] were composite resonators composed of a central block of optical... 

In another conception of nanowire heterostructures with axially modulated composition, Lieber and coworkers generated nanowires with lithographically defined segments of alternating metallic NiSi and semiconducting Ni was thermally evaporated on... 

Lincot, Froment, and Cachet review the chemical and mechanistic aspects of chemical bath deposition of chalcogenide compounds with special emphasis on structural properties associated with epitaxial growth. Present applications of chemically deposited films are reviewed and several characteristic advantages are identified that may be exploited in the future for applications such as small band gap semiconductors, large area electrochromic devices, electroluminescence, quantum sized films, and films with spatially modulated composition and structure. 

In cases where the two c-parameters come into perfect register after small distances, the stmcture is described as a commensurate modulated composite structure. In such circumstances, the value of y is a rational fraction, p q where p and q are (small) integers and the c lattice parameter of the phase is given by... 

In cases where Cj and fail to come into register at all, that is, when piq is irrational, or at least when q is large, the stmctures are called incommensurate modulated composite structures. In order to analyse these incoimnensurate structures, a more complex superspace description needs to be adopted, which involves the introduction of a modulation vector q =yc, where c is a vector corresponding to the basic repeat along the c-axis, corresponding to Cj. 

The AUTOSAR architecture abstracts from the low-level details of electronic control units (ECUs) using a component model and a virtual function bus (VFB), which provides abstract cormnunication concepts between components. The component model allows developers to specify software modules, compositions of modules, ports, and port interfaces. 

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