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Chemical superstructure

Significant recent approaches to chemical reactor network synthesis can be classified into two categories, viz. superstructure optimization and network targeting. In the former, a superstructure is postulated and then an optimal sub-network within it is identified to maximize performance index (Kokossis and Floudas, 1990). [Pg.281]

Lacroix, L.M., Lachaize, S., Falqui, A., Respaud, M. and Chaudret, B. (2009) Iron nanoparticle growth in organic superstructures. Journal of the American Chemical Society, 131 (2), 549-557. [Pg.81]

Fig. 16 TEM pictures of helical superstructures from PS-PIC copolymers in water. The chemical structure and composition of the corresponding copolymers are indicated below the pictures. Reprinted with permission from [238], Copyright (2001) American Chemical Society... Fig. 16 TEM pictures of helical superstructures from PS-PIC copolymers in water. The chemical structure and composition of the corresponding copolymers are indicated below the pictures. Reprinted with permission from [238], Copyright (2001) American Chemical Society...
Assemblage of the dendritic molecules by chemical crosslinking into an array, which is more or less organized. The specific functions of dendrimers can be possibly amplified when they are assembled into superstructures [65]. [Pg.134]

In the mathematical optimization based approaches first a superstructure is created which has embedded a large number of alternative designs. Then mathematical techniques like MINLP are used to find the optimum process within the specified superstructure. For the products considered here there are two big hurdles preventing the large scale use of these techniques (Hill, 2004). Firstly a lot of the physico-chemical phenomena occurring are not completely understood. This makes rigorous modeling difficult. Secondly there is a lack of relevant property models for structured products. [Pg.170]

Achenie, L. K. E., and Biegler, L. T., A superstructure based approach to chemical reactor network synthesis, Comp, and Chem. Engr. 14(1), 23 (1990). [Pg.251]

Yeomans, H. and Grossmann, I.E. (1999) A systematic modeling framework of superstructure optimization in process synthesis. Computers el Chemical Engineering, 23, 709. [Pg.79]

Bond valences can be used in conjunction with other techniques, particularly powder diffraction where, for example, light atoms are difficult to refine in the presence of heavy atoms. Adding the chemical constraints of the bond valence model can stabilize the refinement, particularly in the case of superstructures that have high pseudo-symmetry (Thompson et al. 1999). [Pg.161]

Mesophases of supermolecular structure do not need a rigid mesogen in the constituent molecules. For many of these materials the cause of the liquid crystalline structure is an amphiphilic structure of the molecules. Different parts of the molecules are incompatible relative to each other and are kept in proximity only because of being linked by covalent chemical bonds. Some typical examples are certain block copolymers50 , soap micelles 51 and lipids52. The overall morphology of these substances is distinctly that of a mesophase, the constituent molecules may have, however, only little or no orientational order. The mesophase order is that of a molecular superstructure. [Pg.18]

The ternary iron oxides, as exemplified by the iron-niobium system, offer an opportunity to obtain single-phase, conducting n-type iron oxides in which the conductivity can be controlled by means of chemical substitution. At first glance, FeNbO and FeNb Og might appear to be very different materials. Yet as MM O and MM Og they merely represent superstructures of the basic a-PbO. structure obtained under the conditions of preparation (7 ). Consequently, they form a solid solution in which the two valence states of iron are uniformly distributed throughout a single homogeneous phase (j3). [Pg.207]

Electroswitching of structure takes place when a redox change induces a reversible structural or conformational process in a molecule, such as an electrochemically activated intramolecular rearrangement [8.259]. On the supramolecular level it consists of the electroinduced interconversion between two states of different superstructure. A case in point is the reversible interconversion of a double-helical dinuclear Cu(l) complex M2L22+ [8.260] and of a mononuclear Cu(ll) complex ML2+ in a sequential electrochemical-chemical process [8.261] ... [Pg.132]


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See also in sourсe #XX -- [ Pg.492 ]




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