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The 500MPa ultra fine grained steel grain size changing rule with heating temperature variation of the peak under air cooling was shown in Fig 3.
From Fig 6 it could be seen that in accordance with hardness, the yield strength and tensile strength of ultra fine grained steel declined with the increase of heating temperature compared with the original state, and the yield strength reached its lowest value at 800°C, this was caused by the decline of residual stress inside the material and pearlite spheroidization, which resulted in yield strength decreasing; however, the tensile strength at 800 actually rose slowly, this was because the yield strength of the material was very low, a large number of plastic deformation took place and resulted in hardening, so the fracture strength did not reach its minimum value; in the heating process above 900°C, ultra fine grained steel grain grew seriously, which decreased strength.
Figures 8 and 9 showed the hardness and grain size of 500MPa ultra fine grained steel HAZ with cooling rate t8/5 = 6s.
Conclusions (1) The crystals of 500MPa ultra fine grained steel at HAZ grew obviously, and the range of the grain coarsening temperature was 1000-1200
Chen, Computer Simulation of Austenite Grain Growth in HAZ of Ultra-Fine Grain Steel. 2002, Beijing university of technology: Beijing

Study on evolution of partial texture of different grains during grain growth in IF steels W.
The grain size and evolution of partial texture of small, medium and large grains were investigated during grain growth.
For such large mapping areas, the number of grains ranges between 10 thousand and 50 thousand according to the annealing conditions. 3.
At early stage of grain growth, the sample possesses initial grain size and low ODF level.
(a) (b) Small grains Medium grains Large grains Small grains Medium grains Large grains Fig.3.

Braginsky et al. [7] extended this model to simulate sintering in a complex powder compact consisting of a large number of particles.
Lattice sites having the identical Q number are considered as a grain, and a grain boundary segment is defined to lie between sites of different Q number.
NA and NB are the sites number of phase A and B.
NC is the smaller sites number of that of phase A or B. δQiQj is Kronecker delta function, Qi and Qj denote the grain orientation state of the neighboring sites i and j
It can also be seen when the initial size of matrix particles is increased, the number of nano- particles inside matrix grains decreases, even those nano-particles within the matrix grains are mostly located at the place near grain boundaries.

We determine the number of grains (n1), completely inside the circle (square, rectangle) and the number of grains (n = 2), cut by the circumference.
Fig. 3 Effect of T.T.C cycle number on the size of the austenite grain of 42 CD4 steel: a)- water cooling, b)- air cooling Fig. 3 illustrate the influence of the number of T.T.C cycles on the grain index G for a slow heating of the order of 4 °C.min-1 and for two different cooling.
As number of cycles increases, an increase in the index of the grain G was observed.
The possibility of subjecting a steel grain refinement by a T.T.C is subject to three factors: heating rate, cooling rate and number of cycles (n).
All the results obtained represent the variation of the grain size as a function of the number of cycles (TTC) for two types of cooling and different cooling rates.

In these parameters, former three affect abnormal grain growth behavior through the austenite grain size after reverse transformation.
Abnormal grain growth behavior was evaluated by the area fraction of coarse grain whose austenitic grain size number was less than 5.
The grain size of sample C was measured from fine grain area.
(1) Where rcrit is the critical particle size at which abnormal grain growth occurs, Rm is a grain size of matrix, Z is the ratio of the radii of coarse and matrix grains.
Therefore, abnormal grain growth depends on the matrix grain distribution and the amount of pinning particles.

This model is named as fine-grained access control model based on RBAC.
So when it is so strict with rank and information secrecy, it will be easy to realize and it reduces the numbers of roles.
If only roles can be used, the number of roles required is numerous.
This makes the number of roles reduce and the same role may be in the different departments.
So if we can control these atomic-level objects, fine-grained access control can realize.

They brought on very fine equiaxed grains.
The abscissa shows the grain area.
The number of the pixels shows how many grains were.
These represented that the grain size in this region was very fine, the number was less, and the strips were narrower.
XU Weiping: Associate Professor Master"s Supervisor, phone number:0086 3870876937,fax number:0086 7913953385 e-mail:xuweiping1203@126.com References [1] B.

Although this method can control the grain size and the location of grain boundaries, but has not attempted any control of GBCD and the grain boundary connectivity which may control the performance of polysilicon.
In the case of polysilicon for solar cell, from the design point of view of the cell we need to specify the geometrical configuration of grain boundaries defined by the grain size and grain shape, in addition to the grain boundary character distribution and the grain boundary connectivity already used to understand bulk properties of polycrystal.
(2) Grain Boundary Microstructure and Directional Grain Boundary Density. ) Grain Boundary Microstructure Analysis by OIM.
It is oly a measure of the density of grain boundaries in a polycrystal, under a assumption of the presence of ideally homogeneous grain structure without any difference of grain boundary character and structure between grain boundaries.
The numbers indicate the fraction of random boundaries for respective data points.

In the calculation process alternate using force-displacement method and the Newton's second law, the number of iterations is based on the number of particles and contact points.
Potyondy and Cundall (2004) [5] concluded that the macro-response of a 2D DEM model can be very sensitive to the number of particles.
It becomes less sensitive when the number of particles increases.
Fig. 4 Volume increment to axial strain curves Particle flow model sample shear zone simulation According to a large number of PFC2D simulation tests, get a series of coarse grained soil microstructure parameters, see Table 2.
Coarse grained soil triaxial test of mesoscopic simulation [J].

The shears in one grain are opposite to those in the other grain.
Each grain was discretised into a large number of elements (with 17496 integration points) to effectively capture the complex nature of the plastic fields in the vicinity of the grain boundaries.
Dark lines: grain boundaries.
Grain 2 seems to split into two halves starting from the triple junction with grain 3 and grain 4.
Grain 1 Grain 2 Grain 3 Fig 7 Hypothetical "simple" geometrically admissible strain pattern at a triple junction.