Critical atomic design parameters

Fig. 6. Critical atomic design parameters (CADPs) and critical molecular design parameters (CMDPs) involved in atomic, molecular, supermolecular and supramolecular aufbau leading to natural and un-natural products...

Fig. 16 Critical atomic design parameters (CADPs) structure-controlled (a) size, (b) shape, (c) surface chemistry, (d) flexibility/polarizability, (e) architecture, and (/) elemental composition [94]...

Conversion of styrene to polystyrene is an example of such molecular structure, which is repetitive and simple. Relatively little opportunity is offered to precisely control critical molecular design parameters. Although nanostructure dimensions can be attained, virtually no control over atom positions, covalent connectivity or shapes is possible. 

Fig. 14 Structural control of critical hierarchical design parameters (CHDPs), namely, size, shape, surface chemistry, flexibility/rigidity, composition, and architecture, required for bottom-up synthesis of higher nanostructural complexity manifesting atom mimicry...

Fig. 15 Front cover of Angew Chem Int Ed Engl (1990), 29 138-175 first describing structural control of critical hierarchical design parameters (CHOP) from atoms to macroscopic matter observed during the divergent syntheses of all dendrimers [9]. Copyright Wiley-VCH Verlag GmbH Co. KGaA. Reproduced with permission...

Essentially, all other proposed hard-soft nano-element categories (Fig. 18) evolve from aufbau strategies that allow the control and conservation of critical hierarchical design parameters (CHDPs) from the atomic to the nanoscale level (i.e., CADP —> CMDP —> CNDP). Nature has already evolved very exquisite aufbau strategies for synthesizing other important soft matter nano-element categories such as proteins [S-4], viral capsids [S-5], and DNA/RNA [S-6]. 

The biotic molecular evolution was defined by the respective CADPs of the combined (atoms) required to produce this new molecular level order. It is now known that within this hierarchical level, new sizes, shapes, surface chemistries (functional groups/nonbonding interactions), flexibilities (conformations), and topologies (architectures) arise. These parameters may be visualized by the various shapes, valencies, and polarizabilities associated with the element carbon in its well-known sp, sp, or sp hybridized states. We define fhese unique features as critical small molecule design parameters — CSMDPs. Molecular entities in this domain are generally < 1000 atomic mass units, thus they occupy space of up to approximately 10 A (1 nm) in diameter, when normalized as spheroids. They may be thought of as subnanoscale in dimension. 

For a given ICP-OES instrument, the intensity of an analyte line is a complex function of several factors. Some adjustable parameters that affect the ICP source are the radiofrequency power coupled into the plasma (usually about 1 kW), the gas flow rates, the observation height in the lateral-viewing mode and the solution uptake rate of the nebuliser. Many of these factors interact in a complex fashion and their combined effects are different for dissimilar spectral lines. The selection of an appropriate combination of these factors is of critical importance in ICP-OES. This issue will be addressed in Chapter 2, where experimental designs and optimisation procedures will be discussed. Many examples related to ICP and other atomic spectrometric techniques will be presented. 

In our attempts to develop more active and more stable complexes we probed the role that substituents (both on the N and C atoms of the parent macrocyclic ring) would exert on both the catalytic SOD activity and the overall chemical stability of the resultant complexes. Those structural factors that would affect these two key parameters are not immediately obvious since it was not known at the outset how derivatized ligand systems would affect catalytic activity. Thus, the number of substitutents, their placement, and their stereochemistry could all be critical design elements for maximizing catalytic activity and chemical stability. 

As mentioned earlier the trajectory of the liquid jet before and after the CBL is of importance for design purposes. As we will see, it is also a critical piece of information needed by some empirical-numerical models to simulate the atomization process. A considerable number of research studies have been merely focused on measurements and predictions of the jet trajectory and its variation with change in different parameters such as the pressure and the temperature. To develop a simple model for predicting the jet trajectory, we can think of the jet as a stack of thin cylindrical elements piled on top of each other to form a jet. One such element with infinitesimal thickness h is shown in Fig. 29.1b. Then, one can treat the motion of the element like that of a projectile moving up with initial y-direction velocity j and zero x-direction velocity. In the simplest approximation, the only force acting on the element is the aerodynamic drag force... 

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