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However, it was difficult to observe these submicron grains and submicron grain boundaries under optical microscope.
These elongated grains after the first ECAE treatment were replaced by essentially equiaxed array of submicron grains with an average grain size of ~500 nm after the fourth ECAE treatment, and further were refined to an equiaxed array of fine submicron grains with an average grain size of ~300 nm after the eighth passes ECAE.
And with the increase in the number of ECAE processes, it can be seen that the contact angle decreasing along with surface energy increasing.
Along with the increasing number of pressings, both accumulative strain and misorientation angle consistently increases while grains size and aspect ratio decrease.
In this research, the submicron grains with an average grain size of ~500 nm after the fourth ECAE were refined to an average grain size of ~300 nm after the eighth ECAE treatment.

The burnishing parameters were as follows: burnishing force was 500 N; specimen rotation speeds were 200, 600, and 1200 rpm; feed speed was 0.01 mm/rev; and the number of tool passes was 1.
Grain Size.
Grain size was determined by an intercept method.
The mean grain sizes, d, are also indicated.
(a) Grain size in long axis direction (b) Grain size in short axis direction Fig. 5 Variation of grain size with depth below the surface.

The size of pores after the irradiation was between 0.2~1.2 μm, and mostly distributed at 0.3μm ~0.6 μm; The pores at grain boundary of two adjacent grains was less, the pores at grain boundary were distributed by the way of triangle or quadrilateral.
Fission gases and fission fragments were produced during fuel assemblies being irradiated, and the modality and number of pores would change due to fission outcome.
a) D2 b) D4 Fig. 2 SEM micrographs of specimens Specimens after etched grain boundaries were visible, grain size was about 5μm~30μm, grain size greater than 20μm and less than 10μm were few, mostly grain size distributed at 10μm ~15μm, The pores at grain boundary of two adjacent grains was less, the pores shape distribute at grain boundary presented either triangular or square (Fig 3 arrow or circle diagramming), this viewpoint correspondence match with José R.A.
Table 1 Measurement results of pore size Number of fuel rod Number of specimens Biggest diameter（μm） Average diameter（μm） Pore density（106/cm2） 1# D1 3.293 0.662 0.248 D2 2.297 0.628 0.168 D3 1.732 0.569 0.120 2# D4 1.218 0.427 0.379 D5 1.714 0.482 0.360 D6 1.870 0.442 0.337 Pre-irradiated fuel rod - 1.299 0.329 2.425 Conclusion a) There were cracks in fuel pellets, most micro-cracks were trans-granular crack.
The size of pores at grain boundary of two adjacent grains was less, the pores at grain boundary were distributed by the way of triangle or quadrilateral.

The results showed that compared to the flooding and aerobic treatment, the intermittent irrigation increased grain yield by 7.55-29.58%, which contributed to the increase of seed setting rate and panicle number.
Uptake of metals from the soil by plants can be influenced by a number of plant characteristics and also by edaphic factors including the bioavailability of metals.
Grain yield and yield components (number of panicles per pot, seed setting rate, panicle length and grain weight) were determined.
The Cd concentrations in the grain was above the maximum Chinese level of 0.2 mg/kg.
Comparing the three water management regimes, intermittent irrigation ensured high grain yield combined with relatively low Cd in grain.

M = magnification n = number of particles nd = total number of dislocations intersecting a surface area (NA), (NA) = number of and grains per unit area NA = number of grains per unit area Ni = number of grains intercepted by the field of view of the image (NL) = number of intercepts per unit test line length (Np) = total number of intercepts Nt = total number of grains NV = total number of particles in volume (Nv)1, (Nv)2,...
,(Nv)max = number of spheres in each class interval Nw = number of grains enclosed within the field of view of the image PP = point fraction Pβ = number of test grid points associated with particles Pβ' = total number of test grid points lying completely onto particles Pβ'' = total number of tangential test grid points to particles (Pp) = point fraction of the particles PL = number of point intersections per unit test line length Pt = total number of point intersections or test grid points R = distance between any two spots on a diffraction pattern SEM = scanning electron microscope SV = surface area per unit volume TEM = transmission electron microscope t = specimen thickness VV = volume fraction Introduction Most material properties depend on the microstructure and this has been proved for various materials such as superalloys, composites, steels and aluminium alloys [1-4].
Nt=Nw+½Ni (7) where Nt = total number of grains, Nw = number of grains enclosed within the field of view of the image (e.g. grain A) and Ni = number of grains intercepted by the field of view of the image (e.g. grain B).
For these non-spherical microconstituents, stereological equations relating the number of faces, edges and corners of polyhedron-shaped grains to equivalent grain diameter have been proposed from studies such as those by Matsuura et al. [24].
,dmax, respectively and NV = total number of particles in volume.

In this paper, a deformation test method to reproduce, on a laboratory scale, the microstructure evolution of aluminium alloys occurring during industrial forming processes with a limited number of tests is presented.
Another requirement for the testing method was to cover the parametric ranges of industrial forming processes such as rolling, forging and extrusion and, at the same time, to allow the analysis of varied conditions within a limited number of specimens.
No nucleation of new grains was observed.
Summary and Conclusions An innovative test method was developed to reproduce different deformation conditions with a limited number of tests.
strain, strain rate and temperature) with a small number of specimens (8 for each alloy).

The number of the striations observed in the colloidal crystal under crossed polarized light decreased at some parts in a growth container after the additional centrifugation, while the number also increased at the other parts.
In this study, we tried to reduce the number of stacking disorders in colloidal crystals by centrifugation.
The number of striations in a grain decreased after the above gravitational annealing process (Fig. 4).
The number of striations in another grain increased after the same gravitational annealing process (Fig. 5).
We should collect much more data, and clarify the correlation between the directions and the number of striations in future.

Introduction Since fatigue life is usually controlled by crack growth life, there are a number of reports on the crack growth behavior of conventional grain-sized metals, whereas little has been reported on crack growth of ultrafine grained (UFG) metals.
Fig. 1 Microstructure of the material. 105 106 107 100 150 200 250 Number of cycles to failure Nf Stress amplitude σa MPa □:Coarse grain ●:Ultrafine grain Fig. 2 S-N diagram.
At this stage, a number of microcracks formed from PSB-like SBs are distributed ahead of the major crack tip.
Zhang [8] conducted fatigue tests of UFG aluminum alloy (grain size: 0.4 µm).
At this stage, a high number of shear cracks from PSB-like SBs form around the crack.

The work analyzes application perspectives of Ti-based alloy VT6 (Ti-6Al-4V) with an ultrafine-grained structure with different grain sizes as structural material to produce high-load machine parts.
Two states were taken for comparison 1) ultrafine-grained (UFG) one with an average grain (fragment) size of 0.5 µm; 2) microcrystalline (MC) one with an average size of α-phase grains of 5 µm.
Multiaxial loading at 750oС enabled producing a bimodal state with a UFG-MC structure consisting of a matrix with an average grain (or their fragments) size of 0.8-1.5 µm with inclusion of α-phase grains of about 5 µm.
The average grain size in this state is 1.5 µm.
However, practical application of such materials is hindered by a number of disadvantages, which are first of all reduced thermal stability, impact strength, cyclic crack resistance, increased sensitivity to stress concentrators, pore formation under cyclic loads in the zone of highest stresses (near-the-surface zone).

But the fine sand has some characteristics as grain uniformity, badness gradation, single structure, and the fine grain, and the fine sand filling subgrade is built on the soft soil foundation with high water table, so it is hidden troubles for the fine sand filling subgrade extending and application whether it can liquefy under the tempestuous earthquake load.
But the fine sand has some characteristics as grain uniformity, badness gradation, single structure, and the fine grain, and the fine sand filling subgrade is built on the soft soil foundation with high water table, so it is hidden troubles for the fine sand filling subgrade extending and application whether it can liquefy under the tempestuous earthquake load.
The grain characteristics of fine sand filling The sand engineering characteristics such as penetration, compressibility and strength are mostly depending on the sand grain gradation.
（6） Fig. 2 Liquefaction strength curve of sample 1 Fig. 3 Liquefaction strength curve of sample 2 Table 3 The liquefaction test analysis results Test number Effective confining pressure /kPa Measured data 7。
Conclusions The test results analysis shows that, the fine sand has uniform particles and bad gradation, and the structure is single grain structure with fine grain.ine grain.