Superstructures interaction

Abstract Physical modeling has long been established as a powerful tool for studying seismic pile-soil-superstructure interaction. This chapter presents a series of 1-g shaking table tests aiming at clarifying fundamental aspects of kinematic and inertial interaction effects on pile-supported systems. Pile models in layered sand deposits were built in the laboratory and subjected to a wide set of earthquake motions. The piles were densely instrumented with accelerometers and strain... 

We have assumed so far, implicitly, that the interactions are strictly local between neighboring atoms and that long-ranged forces are unimportant. Of course the atom-atom interaction is based on quantum mechanics and is mediated by the electron as a Fermi particle. Therefore the assumption of short-range interaction is in principle a simplification. For many relevant questions on crystal growth it turns out to be a good and reasonable approximation but nevertheless it is not always permissible. For example, the surface of a crystal shows a superstructure which cannot be explained with our simple lattice models. 

The assembly of two or more subunits to form a superstructure where at least one cooperative intramolecular ring closure takes place permits the assembly of stable complexes using relatively weak interactions. 

As an example of blends with attractive interactions, Fig. 65 shows a superstructure in which interactions between methacrylic acid groups and pyridine side groups of a polystyrene-fc-polybutadiene-fo-poly(f-butyl methacry-late-staf-methacrylic acid) (PS-b-PB-b-P(MAA-sfaf-fBMA)) triblock quater-polymer and a PS- -P2VP diblock copolymer lead to a wavy lamellar structure with cylinders from mixed P2VP and P(MAA-sfaf-fBMA) blocks [194],... 

The study of the cholesteric mesophases obtained by doping thermotropic nematics with chiral, nonracemic compounds, has lead to relevant information about the stereochemistry of the dopants. Chiral interactions change the structure of the phase and therefore molecular chirality can be mapped onto an achiral (nematic) phase to yield a superstructural phase chirality. In 1984 Sol-ladie and Zimmermann published the first review summarizing the state of the art at that time.52 Later on, several review articles updated this subject.53-55... 

Inoue et al. (2003) found that silk proteins will form rodlike structures and that those structure will assemble into comblike or fabric-like superstructure. The scale differences between the rods (nanometers) and the superstructure (micrometers) would suggest that the rod formation is governed by amyloid fibril formation and that the supramolecular arrangement is governed by the properties of the rod (Oroudjev et al., 2002 Putthanarat et al., 2000), namely surface interaction and hydration. Three levels of association could be considered (i) within the proteins internal /1-strands will organize to form intra /1-sheet structures, (ii) /1-sheets from neighboring molecules will associate to form fibril subunits, and (iii) the fibril subunits will further associate to form larger fibrils or rods. 

When the structural configuration is complex or, significant dynamic interaction between interconnected members can not be avoided, a coupled analysis approach can be used. The coupled analysis approach can include as few as two degrees of freedom to represent a structural system or it can involve theuseofmany degrees of freedom in a single, comprehensive dynamic analysis of the entire superstructure. 

Fig. 12 An example of guanidinium-sulfonate superstructures. The fundamental interaction responsible for both robustness and flexibility is the charge-assisted (+)N-H---0( ) hydrogen bonding between the guanidinium cations and the sulfonate anions, which can be varied in shape and length [44]...

The similarity of the various histone fibers is probably correlated with the similarity in the distribution of the amino acids in the sequences of the four core histones and reflects their function as the skeleton or backbone of chromatin. However, from the presence of a specific pattern of interactions of the core histones and the existence of histone variants and histone postsynthetic modifications, one can anticipate modulations in the basic general pattern of histone structure. In Section V, a possible mechanism for histone microheterogeneity influencing chromatin structure is suggested. Analogous to other assembly systems, small subunit modifications may be amplified to produce major changes in the assembled superstructure. 

Choice of lattice linear dimensions Lx, Ly (usually Lx = Ly = L, apart from physically anisotropic situations, such as the ANWII model ). Only finite lattices can be simulated. Usually boundary effects are diminished by the choice of periodic boundary conditions, but occasionally studies with free boundaries are made. Note that Lx, Ly must be chosen such that there is no distortion of the expected orderings in the system e.g. for the model of where due to a third nearest neighbor interaction superstructures with unit cells as large as 4 x 4 did occur, L must be a multiple of 4. 

The classic example in Nature involving multivalent interactions for specific binding is the double helix formation in DNA. Interesting superstructures have been achieved by hybridizing block copolymer based DNA molecules (Jeong and... 

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