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Such a determination of the diffusion mechanism is by all means quite primitive, because in a number of publications (see, for instance, [11]) it was shown that grain-boundary diffusion can be realized by very complicated mechanisms of jumps of the diffusing atoms.
Numbers denote spectrum components The high-temperature section of the plots shown in fig. 2 corresponds to the beginning of the Mössbauer atoms pumping from grain-boundaries into the volume.
Emission 57Co( 57Fe) spectra of HPT W annealed at various temperatures Numbers denote spectrum components Table 1.
At heating up to 6000 С small grain sizes are retained but recovery proceeds, and grain boundaries get straighter and thinner while grains proper depurate of dislocations.
A decreased electron density on the Mössbauer isotope nuclei in near-boundary areas was also observed in a number of polycrystalline metals in [3,4], and this effect was attributed to the presence of interstitials segregation in these areas.

Introduction Grain growth is commonly treated as a process of grain boundary migration not affected by triple junctions (TJ).
Grain growth kinetics is described by temporal alterations in the distribution and the mean grain size.
Grain growth kinetics in polycrystals with 0D = 68 lu and different m (see numbers).
If, however, second phase particles, pores or a low grain boundary mobility retard normal grain growth and lead eventually to the commencement of abnormal grain growth, the ratio increases with time steadily.
Time dependence of Dmax/DM in polycrystals with 0D = 68 lu and different m (see numbers).

Introduction Grain supply chain is refers to the best cooperation relationship established by the grain processing enterprise and its suppliers, distributors.
Selection model of sales channel on grain supply chain Model hypothesis.
Grain processing enterprise’ marginal cost is , equilibrium price is .
relations transformation---- number of downstream sales enterprise, as name as would be got.
In sum, research shows that with the number of the downstream sellers continue increasing, division is the development trend, and condition of part of the integration (double channel) is the most easy to meet.

Results and Discussion Figure 1 shows the hardness variations with respect to the number of ECAP passes for 4N-Al and 5N-Al.
The hardness of 3N6-Cu increased continuously with increasing number of ECAP passes as shown in Fig.2.
Fig.2 Hardness variation with respect to number of ECAP passes for 3N6Cu and 7N-Cu.
Fig.3 Hardness variation with respect to number of ECAP passes for 4N-Al and 5N-Al.
The fine-grained structure in 5N-Au suggests that the coarse grains in 5N-Al are not due to grain growth at the ECAP temperature.

However, not only triple junction drag affects grain growth and grain microstructure evolution.
As shown [10, 12,14,15] grain boundary triple junctions do not only drag grain boundary motion and grain growth, but also change essentially the evolution of grain microstructure during grain growth.
For large (large or grain size) grain growth kinetics is determined by the grain boundary mobility and follows a parabolic law: i.e. the mean grain size .
The generalized von Neumann–Mullins relation [17] in terms of the temporal change of the grain area S can be expressed in terms of Λ: for (9) for (10) where . n is the number of the triple junctions (neighboring grains), is the grain boundary surface tension and .
However, the beauty and mathematical clarity of the von Neumann-Mullins relation encouraged a number of attempts to search for a 3D analogy of this relation [19-22].

It is clear that a tracer atom need not sample a large number of grains and grain boundaries in order for its effective diffusivity to be given by the Hart Equation (Eq. 1).
In a diffusion experiment, it can be expected that tracer atoms will traverse a number of grains in the diffusion time.
The direction of the random walks of the particles and the evaluation of the spatially dependent jump frequencies (which represent the diffusivities) is made using random numbers.
To simulate a thin-film tracer source 10 6 particles are created and released from the surface and allowed to diffuse for a time t (proportional to the number of jump attempts per particle).
These concentration profiles are built up simply by determining the number of particles that have reached a given distance from the tracer source plane after time t.

Area intensities of grain and subgrain boundaries, length intensities of triple grain and subgrain junctions, structural homogeneity and its thermal stability are strictly dependent on the number of passes.
It is generally believed that the grain structure improves with the number of passes but detailed structural studies are rather rare.
Let NA be the number of profiles per unit area of the test plane and NL the number of intercepts per unit length of the test line.
The effect of number of passes and subsequent annealing on the total intensities S, L [S] [µm-1] [L][µm-2] Number of passes 2 4 8 12 2 4 8 12 As pressed 1.1 1.6 2.1 1.6 1.1 1.9 3.4 1.8 After annealing and creep 0.28 0.28 0.29 0.35 0.09 0.11 0.10 0.13 Fig. 2 The effect of the number of passes on the fractions of boundary areas (left) and triple grain junction lengths (right) with misorientations in three intervals: subgrains 2 o ≤ ∆ < 10 o, intermediate boundaries 10 o ≤ ∆ < 15 o and grain boundaries ∆ ≥ 15 o.
Summary With increasing number of passes, the increase of boundary misorientations gradually proceeds; subgrains become grains but the total boundary area of grain and subgrain boundaries remains nearly constant.

Then, the authors have been studied about the strength of thin wires of ferrous and aluminum alloys, and found that the scatter comes from the number of crystal grains in the cross-section because strength is affected by the orientation of the crystal grains [1, 2].
where n is the number of pass, F (rad) is the channel-intersection angle, and Y (rad) is the angle of curvature at the outer point of intersection of the two channels.
The S-N curves for thin plates are shown in Fig. 8, where arrows indicate that fatigue tests were terminated at this number of cycles.
ECAP method is superior because UFG can be made by less number of pass
Nakai, Kobe University), and Grant-in-Aid for Scientific Research (A) by the Japan Society for the Promotion of Science under proposal number of 24246024 (Head investigator: Professor T.

And the pulling velocity should be controlled less than 0.5 mm/s in our experiment so as to effectively decrease the grain number and mean grain deviation.
Fig. 4 (b) shows the influence of pulling velocity on the grain number and mean grain deviations at the cross section of z=0.45 m.
The grain numbers fluctuate at 35 and mean grain deviations fluctuate at 15° with the range of pulling velocity from 0.1 mm/s to 0.4 mm/s.
Since fewer grain number and mean grain deviation are pursued, the pulling velocity should be controlled less than 0.5 mm/s in our experiment.
And the grain number decreases and the grain transverse size increases with increasing distance from the bottom surface of the casting.

Introduction Now, grain bagging machine has been widely used in grain storage of grain depot [1].
Grain conveyer device.
Grain bagging device.
The fixture is composed of a number of bars, with elastic rubber belt fasten, to prevent the bag off.
Acknowledgements The work has partly been Supported by Leading Academic Discipline Project of Shanghai Municipal Education Commission, Project Number: J51902.