Diffusion nanostructured materials

Majer, G., Eberle, U., Kimmerle, F., Stanik E. and Orimo, S. (2003) Hydrogen diffusion in metallic and nanostructured materials, Physica B 328,... 

It should be note the important role of nitrogen diffusion for determining the nanostructured material. Nitrogen atoms being consolidated at the subboundaries could block the processes of recovery and stress relaxation, resulting in pronounces refinement of grain structure. 

In recent years, nanotechnology has opened a new window on the physical-chemical properties of semiconductor materials nanostructuration. The development of nanostructured materials (nanowires, nanotubes, nanoparticles etc.) enables improvements in the response and recovery times of the sensor signal, due to the reduction of gas diffusion effects in the bulk of the material. Additionally, the sensitivity and the sensor response are also improved by the changes in the conduction mechanisms at the nanoscale and, finally, the reduction of the dimensions of the device allows the reduction of the power consumption by the system. 

Nanoparticles can be identifled by their physical sizes in the range from 1 to 100 nm [2-5], Typically particles consist of primary particles - crystallites or clusters [6], Clusters form nanoparticles (Fig. 5.2) or grains in nanostructured materials by diffusion controlled ripening or accommodation. The control of the size, shape and structure of the nanoparticles in technological process is becoming important due to strong correlation between these parameters and magnetic, electric and elastic properties. 

Nanostructured materials are a subject of growing interest in catalysis since they are expected to exhibit enhanced catalytic reactivity when compared to conventional materials [6]. We have previously used a counterflow diffusion flame burner to produce and study the formation of nanostructured oxides and mixed oxides [7][8]. 

Anta JA, Mora-Sero I, Dittrich T, Bisquert J (2008) Interpretation of diffusion coefficients in nanostructured materials from random walk numerical simulation. Phys Chem Chem Phys 10 4478 485... 

Over the past few years, research efforts have focused on the use of nano-structured anode materials (nanoparticles, nanocrystals, nanowires, nanorods etc., including complex core-shell and composite structures) in order to mitigate the effects of volume change upon Li uptake. Nanostructured materials present the add-on advantage of shorter diffusion distances for Li species, thus offering the possibility to increase charging and discharging rates (i.e., battery power). This chapter will essentially concentrate on such recent developments. 

Apart from these few examples, most nanostructured materials are synthetic. Empirical methods for the manufacture of stained glasses have been known for centuries. It is now well established that these methods make use of the diffusion-controlled growth of metal nanoparticles. The geometrical constraints on the electron motion and the electromagnetic field distribution in noble-metal nanoparticles lead to the existence of a particular collective oscillation mode, called the plasmon oscillation, which is responsible for the coloration of the material. It has been noticed recently that the beautiful tone of Maya blue, a paint often used in Mesoamer-ica, involves simultaneously metal nanoparticles and a superlattice organization [3.1]. 

The kinetics of diffusion occurring in nanostructured materials is a subject of intensive study [178,179]. Materials at the nanoscale showed sharp acceleration of diffusion [180], indicating the lowered activation energy of diffusion. The activation enthalpies for the interfacial diffusion are comparable to those for surface diffusion, which are much lower than those for diffusion along grain boundaries [181, 182]. 

This increased tortuosity, will, no doubt, compel them to travel a longer path to diffuse through the nanostructured materials. 

Using a solvent carrier to diffuse a new molecular species into a microphase-ordered block copolymer provides a plethora of new possibilities in terms of nanostructured materials development. One such possibility that continues to... 

Krishna (2000), starting from the fundamental concepts of Maxwell J. C. and Stefan X, describes the conhguration diffusion, also called surface diffusion, within zeolite crystals by means of the following set of equations, namely the generalized MS approach (Kapteijn et al, 2000 Krishna, 2000). Nevertheless, this set of equations can also be used to describe diffusion in other nanostructured materials such as carbon nanotubes ... 

Chemical scientists will seek new methods of generating nanostructures with a range of materials and processes that rely on ideas common in chemistry—self-assembly, diffusion, phase-separation, catalysis, wetting—to make these structures accessible and inexpensive. 

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