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A number of experiments and calculations have been carried out to clarify the specific electronic and magnetic properties of CNTs [7, 8].
The grain size of α-Fe2O3 (110) crystal plane is 62.5nm, the γ-Fe2O3 (311) crystal plane is 37.6nm for Na2CO3 and is 35.1nm for CO(NH2)2.
The grain size of α-Fe2O3 (110) crystal plane is 62.5nm
The grain size of γ-Fe2O3 (311) crystal plane is 37.6nm, and its Ms is around 10.5 emug-1
The grain size of γ-Fe2O3 (311) crystal plane is 35.1nm, and its Ms is about 9.7 emug-1 .

During the sintering of fine WC-Co alloy, control of WC grain growth is one of the most critical concerns.
Measures to inhibit the WC grain growth include powder mixing, carbon control, sintering temperature and addition of grain growth inhibitors.
Up to now, VC would be the most effective dopant to retard the WC grain growth compared to the other refractory carbides, Cr3C2, TaC and NbC [1,2].
Knowledge of the phase relations and thermodynamic properties of the Co-V-C system is crucial to understand the effect of VC in inhibiting the grain growth of WC-Co alloy and the mapping of the W-Co-V-C phase diagram.
The number of sublattice sites, a and c, on each sublattice depends on the crystal structure.

The microstructure of the steel with solution treatment consists of equiaxial grains (Fig.1 (a)).
With increasing cold working level from 0% to 20%, the grains are lengthened gradually, and some grain boundaries disappear (Fig.1 (b)).
When the level up to 40%, grain boundaries are cut by slip line, intergranular defects increases, and the deformed zone obviously appears (Fig.1 (c)).
When the cold-rolling level increases up to 60%, the grain boundaries disappear completely, the fibrous tissue of cold-rolling can be observed obviously (Fig.1 (d)).
Due to the increment of the defect from 0 to 60% cold rolling deformation, the number of nucleation site of pitting corrosion increases, so the pitting corrosion resistance of the steel is degraded by cold working.

Introduction Reversible martensitic phase transformations provide a number of alloys, called shape memory alloys (SMAs), with the capabilities of shape memory, superelasticity, biocompatibility and damping behavior [1-3].
The microstructure appears to be homogeneous with a grain size of about 90 μm.
Microstructures after dynamic compression deformation The microstructures of Ni-Ti shape memory alloys at high strain rates were presented Fig.4.It can be seen from Fig.4 that deformation of the grains were uniform and the grains were elongated and thready.
There were lots of parallel striped microstructures in every grain, which are in the direction of 45o within the grain because of the preferred orientation of martensite.

It is viewable that Mg20Ni10 and Mg20Ni6Cu4 alloys exhibit an entire crystalline structure with a grain size of about 20 nm, and Fig. 1 HRTEM micrographs and ED patterns of the as-spun (20 m/s) alloys (a) Mg20Ni10, (b) Mg20Ni6Co4, (c) Mg20Ni6Cu4 their electron diffraction (ED) patterns appear sharp multi-haloes, corresponding to a crystalline structure.
The substitution of M (M=Cu, Co) for Ni brings on the obvious refinement of the grains of the as-cast alloys.
The superior hydrogen absorption kinetics is undoubtedly associated with the refinement of the grains generated by the melt spinning.
Consequently, high densities of crystal defects such as dislocations, stacking faults and grain boundaries are introduced.
The large number of interfaces and grain boundaries available in the nanocrystalline materials provide easy pathways for hydrogen diffusion and accelerates the hydrogen absorbing/desorbing process [7].

Such a method can fulfill the demand for energy saving because when a thin bar is directly cast from molten metal, the molten metal is rapidly solidified, which confers a number of advantages.
The grains in these cross sections are fine.
The grains in the cross section of the bar cast with these speeds are finer than those in the bar cast at slower speeds.
As shown in the photograph, the grains are fine.
The cast bar had fine grains and no surface defects.

According to the equilibrium equation of the dislocation distribution, the following wxpressions can be got: (1) where is the Burgers vector of each dislocation, is the Poisson's ratio of material, represents the number of dislocation between and .
The solution of equation (1) is (3) This distribution is regarded as a micro crack with the length-, the displacement discontinuity produced by shear where has the distance of far from crack tip is: (4) Based on reference [5], the crack propagation criterion is (5) where is surface energy density of a crack extending at grain boundaries (interlayer), is shear stress intensity factor at the end.
Experiments have proved that，with the high aluminum content, grain boundary precipitates brittle phase easily and will decrease.
Research has shown that, no matter parallel grain boundary twin, vertical grain boundary twin, or tilt grain boundary twin will have a common phenomenon-intergranular fracture[7].

In automotive, the number of circuits required in wiring bundles is increasing due to the diversification of electronics within vehicles.
Grains are strongly oriented along the drawing direction.
The longitudinal grains lengthening is less pronounced and a thin strip nucleate at the interface.
The heat-treatment performed after drawing operations of CCA gives rise to a granular growth with an aluminum grain growth more pronounced than for copper grains.
Fox, Formation of ultrafine copper grains in copper-clad aluminum wire, Scripta Mater. 63 (5) (2010) 488 – 491

In addition, according to the well-known Scherrer formula [3], the crystalline grain size of AlN is calculated about 28 nm.
The surface morphology consists of a large number of hexagonal crystalline grains with no visible pores and defects over the film.
The rounded and homogeneous grain shape can be observed from the picture.
Besides, the grain boundaries among columns in film and the good cohesion between the AlN film and Bragg reflectors are observed from the images, obviously [4].
The AlN film with (002) texture has a rounded and homogeneous surface morphologies with low roughness and the crystalline grain size is calculated about 27 nm.

Introduction Since the superior mechanical properties of Si3N4 based ceramics have been attributed to hexagonal rod-like grain shape due to the anisotropic grain growth of β-Si3N4 [1], understanding of grain growth kinetics is a key issue in order design high-toughness and high-strength materials.
Therefore, it is also a fundamental issue for the clarification how the grain growth behavior is affected by the physical properties (viscosity, surface tension and wettablity, etc.)
Continuous decreasing in their ionic radii with atomic number causes remarkable variations in the various properties of the rare earth containing glasses [8-12] that are the grain boundary phase of Si3N4 ceramics sintered with rare earth oxide additives.