Canonical assembly

AB diblock copolymers in the presence of a selective surface can form an adsorbed layer, which is a planar form of aggregation or self-assembly. This is very useful in the manipulation of the surface properties of solid surfaces, especially those that are employed in liquid media. Several situations have been studied both theoretically and experimentally, among them the case of a selective surface but a nonselective solvent [75] which results in swelling of both the anchor and the buoy layers. However, we concentrate on the situation most closely related to the micelle conditions just discussed, namely, adsorption from a selective solvent. Our theoretical discussion is adapted and abbreviated from that of Marques et al. [76], who considered many features not discussed here. They began their analysis from the grand canonical free energy of a block copolymer layer in equilibrium with a reservoir containing soluble block copolymer at chemical potential peK. They also considered the possible effects of micellization in solution on the adsorption process [61]. We assume in this presentation that the anchor layer is in a solvent-free, melt state above Tg. The anchor layer is assumed to be thin and smooth, with a sharp interface between it and the solvent swollen buoy layer. 

Abstract In contrast to canonical histones, which are assembled into nucleosomes during DNA... 

While some histone variants can become deposited during DNA replication, certain variants also are assembled into chromatin in a replication-independent manner (reviewed in Jin et al. 2005). This allows the incorporation of histone variant into chromosomal regions with high levels of histone turnover. Histone variants can distinguish the affected nucleosomes from their canonical counterparts and are likely to have important function in the specialization of chromatin domains and their epigenetic maintenance. 

One can do dynamics under this Hamiltonian by making the trajectory undergo an elastic reflection whenever it strikes one of the infinite barriers (14). Under H, the different parts of S would be visited with the same relative frequency as Tn an unconstrained equilibrium machine experiment, but with a much greater absolute frequency thereby allowing a representative sample of, say, 100 representative points on S to be assembled in a reasonable amount of computer time. If the equilibrium distribution is canonical the momentum distribution will be Maxwel1ian and independent of coordinates hence, representative points (p,q) can be generated by taking c[ from an equilibrium Monte... 

There are two basic approaches to the computer simulation of liquid crystals, the Monte Carlo method and the method known as molecular dynamics. We will first discuss the basis of the Monte Carlo method. As is the case with both these methods, a small number (of the order hundreds) of molecules is considered and the difficulties introduced by this restriction are, at least in part, removed by the use of artful boundary conditions which will be discussed below. This relatively small assembly of molecules is treated by a method based on the canonical partition function approach. That is to say, the energy which appears in the Boltzman factor is the total energy of the assembly and such factors are assumed summed over an ensemble of assemblies. The summation ranges over all the coordinates and momenta which describe the assemblies. As a classical approach is taken to the problem, the summation is replaced by an integration over all these coordinates though, in the final computation, a return to a summation has to be made. If one wishes to find the probable value of some particular physical quantity, A, which is a function of the coordinates just referred to, then statistical mechanics teaches that this quantity is given by... 

The assembly that results from these conditions is called the canonical assembly Let us formulate the conditions which it must satisfy. It... 

Not only can a canonical name be assigned to "simple" molecules such as dodecahedrene (with 20 atoms), it is also "relatively easy" to canonically name high symmetry moieties, such as the 5880 atom ion with empirical formula C29ooH23ooN6oPi2oS6o02ooFi8oPt6o that self-assemblies into a supermolecular dodecahedron [49] where each of the twenty carbon atoms... 

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