Controls distance

An equally important challenge for nanocrystal assembly is the fonnation of specific nanocrystal arrangements in solution. By using complementary DNA strands as tethers, Mirkin et al [102, 103] fonned aggregates of gold nanocrystals with specific sizes Alivisatos et al also used DNA to stmcture semiconductor nanocrystal molecules, though in this case the molecules contained only a few nanocrystals placed controlled distances from each other [104, 105 and 106]. The potential applications of biomolecular teclmiques to this area of nanoscience are immense, and the opportunities have been reviewed in several recent publications [107, 108, 109 and 110]. 

Experiments with shaped nanoholes (in contrast to circular holes) offer new possibilities of control over the spectroscopic response of adsorbed species. This is because anisotropic structures present polarization-dependent conditions for SP excitation [29,58-60]. Moreover, apexes in hole structure can further localize the light field, as illustrated in Fig. 10. The double-hole structure in Fig. 10 is formed by two nanoholes holes (150 nm diameter) separated by a controllable distance [29,61-65]. The SP resonance depends, then, not only on the same parameters as the circular holes (such as hole diameter and array periodicity), but also on the presence of the apex formed when the two holes touch each other, as shown in Fig. 10c. The apexes act as an optical antenna, focussing the electromagnetic field to a very small region, as shown in Fig. lOd, which is a FDTD calculation of the field distribution around a double-hole with overlapping holes. 

Controlling Distances Between Oxide Particles In Water... 

Such structures represent a case where the attempt to control distances appears to have succeeded. All opposing surfaces are at the same distance d, idilch can be varied to some extent by manipulating the electrostatic repulsions (12). However this control Is possible only In a narrow range of conditions ... 

The reported tip-sample distance control methods and the typical values of the resultant controlled distance in TERS experiments are summarized in Table 16.1. 

Once model glycopeptoid syntheses had been established, we decided to prepare sialic acid oligopeptoids having controlled distances both between the backbone... 

In this study, one mutant includes a pair of cysteines placed within a single helix to provide an internal distance control. Distance distributions were obtained by DEER measurements and Tikhonov regularization. Studying ASYN bound to detergent and lysophospholipid micelles, it has been shown that the inter-helical... 

Tunneling current controls distance between sample and very sharp tip... 

Prom a more fundamental point of view, microlatexes may provide a way of studying photo-induced reactions in which an energy transfer is made over some controlled distance ( 10 A) following reduction of diffusion effects in the polymerised particle. 

By use of a manual or motorized computer-controlled micromanipulator with 0.2-pm x-y-z- resolution, the porphyrinic sensor can be implanted into a single cell, placed on the surface of the cell membrane, or kept at a controlled distance (0.2-10 pm) from an NO generating cell [16,25,52-58]. 

Clearance. A controlled distance by which one part of an object is kept separated from another part. 

The design and synthesis of new tailor-made catalysts, optimized for specific reactions, requires an ability to control distances between catalytic sites and an understanding of the activity and interactions between the catalytic sites. This is also true for bifunctional catalysts (e.g., Pd/HZSM-5 catalysts for the hydrogenation of aromatics, where the presence of two different, nearby active sites is required for reaction. Here results for new NMR probe molecules are shown that can be used to estimate distances between catalytic sites. Using a combination of techniques including solid-state NMR the densitiy of Bronsted add sites in zeolite HY with diphosphine molecules was determined. ... 

As NHSK materials are functionalized and dispersed at controlled distances from one another, they are ideally suited to produce novel nanocomposites which can be tuned both through dispersion and steric hindrance [234]. 

The obtained results may be regarded as an important intermediate step forward to a synthesis of fully siloxane polymers with a controllable distance between the constitutive organosilsesquioxane fragments of their molecules. 

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