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Introduction In polycrystalline materials, propagation of a cleavage crack from grain to grain is a complex process.[1] This is because cleavage occurs on well-defined planes and these planes in neighbouring grains do not usually meet in a line at their common grain boundary.
In addition there is a significant number of deformation twins formed on {10-12} planes ahead of the growing crack.
Hence the stepped cleavage has the effect of limiting the amount of grain boundary fracture that is required as cracks propagate from grain to grain.
This minimises the amount of grain boundary fracture needed to accommodate the mismatch between grains.
Accommodation at a grain boundary in low temperature fracture of Zn as the crack propagates from grain A to grain B is shown in (d).

The weld nugget zone is composed of uniform fine equiaxed grains, while thermo mechanically affected zone is composed of slender coarse grains.
The average grain size is 9.5μm.
Then dislocations begin to move and grain grows unceasingly.
The average grain size is 13μm.
(3) Fine equiaxed grains were evenly distributed in the NZ area, while elongated coarse grains were observed in TMAZ area.

There tends to be a higher density of dispersoids near the grain boundaries than in the centre of the grains, and this non-uniformity is found to be due to the presence of the cored dendritic structure after casting[4, 6], as there is not enough time to level out the microsegregations through diffusion before nucleation begins.
After grinding, the samples were polished with a fabric with diamond spray with grain sizes down to 1 µm.
These were taken in a straight line through the alloys, covering a distance of 1500 µm, crossing approximately 18-22 grains.
Results Number Density and % Area.
Fig.2 shows results for the number density and % area of both alloys.

Based on the results of cellular automaton, the transformation fraction of α phase is calculated with the number of lattice and isothermal phase transformation kinetic equation is also calculated with data of transformation fraction, and the effect of hot compression deformation parameters on phase transformation is also discussed.
For simplicity, the phase transformation process is divided into two stages, i.e., formation of initial microstructure and phase transformation process.The initial microstructure is created via a normal grain growth algorithm and dislocation density is uniform and identical for all primary grains.It is considered that the driving force for nucleation is provided by the variation of disloation density.The dislocation densityof a deforming matrix at every time step increases based on the dislocation density .If the dislocation density of a chosen cell exceeds the critical dislocation density,the cell becomes a nucleus for phase transformation.For a newly formed grain,the initial dislocation density is set to zero inside the grain,and increases as the grain grows with hot compressing deformation of the matrix.If impinge each other,the growing grains cease to grow in the impinging direction, but continue to grow in another direction with the increase of strain.When the dislocation density of
a phase transformation grain reaches the saturation value,the grain ceases to grow.And if all the phase transformation grains cease to grow,the phase transformation process terminates[7].
It is proposed in the present study that nucleation of phase transformation occurs only at grain boundaries.Nucleation of phase transformation is related to the accumulation of dislocation,and when dislocation densityexceeds the critical dislocation density,nucleation occurs at grain boundaries at a nucleation rate.For the hot compression deformation the critical dislocation densitycan be experssed as[9]: (4) Where M is the total number of CA cells,is the deformation temperature,and N is the number of phase transformation cells which varies as the function as well as m,where m is the strain rate sensitibity.
For a newly formed grain,the initial dislocation density is set to zero inside the grain and increases when the grain grows with continued deformation of the matrix.When the dislocation density of the phase transformation grain reaches the saturation value,the grain ceases to grow.The value ofcan be calculated by[9]: (5) Results and Discussion Microstrutural evolution of phase transformation.

The microstructure contained grains with an average size of 195 nm and 239 nm, respectively.
In the reported work HE was used to refine the grain size of 6082 aluminium alloy.
From the application and economic points of view it is important to minimize the number of extrusion passes required to achieve the required properties.
The grain sizes were determined using the stereological method and XRD analysis, which enabled the average grain size to be determined by measuring the full width at half maximum of the diffraction peak profile.
The nanometric-size of grains in the alloy's structure was confirmed by XRD analysis although The grain sizes were calculated as 195 nm in the multi-pass sample and 280 nm in the single-pass sample.

To achieve this goal, we proposed a fine-grained access control model for smart grid.
The System Model of Smart Grid The system of smart grid will use large numbers of networked sensors, power electronic devices, distributed electricity generators, and communication appliances act together in order to deliver the intelligent grid and maintain security and control, communications, energy efficiency, environmental integration and accessibility.
A Fine-grained Access Control Model In this work, we build the fine-grained access control model based on the traditional RBAC model, and using the same system components in our model.
Fig.3: A Fine-Grained Access Control Model based Access-trust-degree and Rights be Used Frequency In this model, when user want to access to the smart grid, he will sent the request to the data control platform at fist, then his access-trust-degree will be calculated by data control platform.
Summary In this paper, we proposed a fine-grained access control model based on the algorithm of access-trust-degree.

In order to obtain the high hot-strength in high-temperature service, the alloying degree of nickel-based superalloy is increasing which leads to the decreasing the stability of microstructure during the high-temperature and long-time service, and even a lot of TCP precipitation phase at the grain boundaries which leads to the appearance of the brittle failure in a large number of caused by catastrophic the phenomena of disastrous brittle failure[2].
A large number of dimples exist in tensile fracture without aging treatment.
The precipitation phases within the grain transform to grain boundaries during the long-term aging, which increase the size of precipitation phases at grain boundaries.
The needle-like precipitation phases along the grain boundaries or growing into grain can be observed.
With prolonging aging time, grain boundary precipitation phases continue to grow, the interface of precipitation phases and substrate replace a large number of grain boundaries.

We used the same inelasticity and friction coefficients for grain−grain and grain−wall collisions including the horizontal base.
The variation of the packing fraction ρ(t) with the number of shakes t for several tapping intensities ξ is presented in Fig. 1, where more dissipative grains (disks (A)) have been used.
In this study we work with the following definition of the grain mobility: ( ) ( ) ( ) ,1 1 1∑= −+ −= N i i i d tyty N tµ (3) where N is the number of particles, yi(t) is the y−coordinate of the ith particle at time t and the angular brackets denote an average over independent runs.
When compaction goes on, the grain mobility decreases.
An example is given in Fig. 3 where we have plotted both mobility µ(t) and density ρ(t) as functions of the number of taps t.

Spherical grains are excessive alumina after burning or dissolvable phase.
The results showed that rod-like Crystal is very likely the CaCO3 and MgCO3 [9].The reactions are as follows: As shown in Fig. 3g the rod-like crystals become thick but the number of them is reduced after hydration for 24h.
Instead there appear a large number of mesh or beard shape crystals.
The stick big grains are not appeared.
The stick big grains are not appeared.

Thereby it reduces the number of shutdown to ensure the safe operation of the boiler and create the favourable vield and social benefits.
It clearly shows there is a clear boundary line and discontinuous columnar crystal in sample 1.The organization is uneven and there is a large number of bright coarse-grain on the left side.
And the grain is very small.
And the grain tapered from the inside out.
Then it is coarse-grained zone and fine-grained zone.