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Each of the mc-Si blocks is wire-sawed into a number of mc-Si wafers of certain thickness such as 200um.
Grain boundary.
Heterogeneous nucleation can be formed near the crucible wall result in generating fine grain and producing a large number of grain boundaries at the same time.
Heat stress direct result in the grain produced a large number of dislocations [10-11].
Grain distribution was not uniform in the wafer, the grain size on the side adjacent to the crucible was smaller, and the grain size on the other side is relatively larger.

As it is shown in Fig. 1 grain B is too big and grain A is too small.
Only some of abrasives are active, which means they roll like grain C or slide like grain D.
First of all strongest loaded grains disintegrate.
As a consequence, the structure of the lapping tool is changed, as follows: the number of bigger grains diminish, while the number of smaller grains is growing.
Due to the changing track and velocity of abrasives, some grains crash with each other or with grain fragments.

Nucleation at boundary Twinning Recrystallization at prior grain boundary Recrystallization associated with particles Nucleation associated with second phase particles 50 µm 30 µm 30 µm Journal Title and Volume Number (to be inserted by the publisher) Fig. 3 Dynamic recrystallization and twinning in Alloy A1 extruded at 573 K Experimental Alloy A1 Summary.
Many of those new grains were associated with grain boundary particles.
Fig. 7a Nucleation of new grains in WE43 extruded at 633 K New grains beginning to nucleate dynamically in shear band Evidence of dynamic recrystallization at preexisting grain boundary Build up of subgrain boundary around particle Shearing of grain during deformation Recrystallization associated with particles along pre-existing grain boundary Recrystallization associated with particles Nucleation at grain boundary Nucleation at particles Fine particles that precipitated out during extrusion 25 µm 8 µm 10 µm 12 µm Journal Title and Volume Number (to be inserted by the publisher) The microstructure of WE43 extruded at 663 K is shown in the EBSD map in Fig 7b and it is possible to identify new grains recrystallizing.
New grains also nucleated at grain boundaries and those new grains were often associated with grain boundary particles.
New grains were observed nucleating at particles within the matrix and at grain boundaries.

Afterwards, alloys with different amounts of Iron, namely 0.25 %, 0.5 % and 1.0 % (all numbers in this article given in wt.%) were produced.
Even if the absolute numbers coming from the simulations might be doubtful, trends can be simulated correctly.
The grain boundary particles acted as grain refiners and stabilized the grain size up to temperatures of 1100 °C [11].
The number of grain boundary particles was reduced and the distance between the particles was increased.
Consequently, the number of particles located inside the grains increased with increasing Iron contents as well.

In several previous studies on various metallic systems, this behavior has been attributed to a number of factors, including extrinsic processing artifacts such as porosity, insufficient bonding, and impurities [5], as well as to intrinsic microstructural factors related to deformation mechanisms, such as high density of lattice imperfections and small size grains resulting in a low strain hardening ability [6].
The micro grains that are present in bimodal materials are known to suppress crack growth and facilitate strain hardening as a result of increased spacing for significant numbers of dislocations to intersect with each other and consequently accumulate during deformation [20].
Addition to embrittlement via initiating crack growth, grain boundary segregation will suppress grain boundary sliding [25, 29], which is widely known to be a dominant deformation mechanism in nanocrystalline and ultrafine grained materials [30, 31].
First, the distribution of grains in the starting powder and second, grain growth during the degassing and QI forging steps.
As discussed in the introduction part, the large grains can increase strain hardening ability by providing enough space for significant numbers of dislocations to intersect with each other and consequently accumulate during deformation, and therefore enhancing the uniform elongation and ductility.

Behavior of Basal Plane Dislocations and Low Angle Grain Boundary Formation in Hexagonal Silicon Carbide Yi Chen1,a, Govindhan Dhanaraj 1,b , William Vetter 1,c , Ronghui Ma2,d and Michael Dudley 1,e 1 Department of Materials Science and Engineering, Stony Brook University, Stony Brook, NY, USA 11794 2 Department of Mechanical Engineering, University of Maryland Baltimore County, Baltimore, MD, USA 21250 a yichen1@ic.sunysb.edu, bgdhanaraj@ms.cc.sunysb.edu, cwvetter@ms.cc.sunysb.edu, d roma@umbc.edu, emdudley@notes.cc.sunysb.edu Keywords: Low angle grain boundary, Basal plane dislocation, Dislocation dipole Abstract.
The three-dimensional (3D) distribution of BPDs can lead to aggregation of opposite sign edge segments leading to the creation of low angle grain boundaries (LAGBs) characterized by pure basal plane tilt of magnitude determined by the net difference in densities of the opposite sign dislocations.
It is also believed that the influence of low angle grain boundaries (LAGBs) on device performance is related to the presence of BPDs which in part comprise them.
The three-dimensional distribution of BPDs in the crystal caused by the thermal gradient will lead to the formation of low angle grain boundaries in SiC.
Colin Wood) and by Dow Corning Corporation under contract numbers N0001405C0324 and DAAD1701C0081.

This was because when the alloy was sensitized during 700~725℃, diffusion speed of chromium increased, the number of grain boundary carbides increased compared with 650℃.
The number of coarse carbide increased obviously, and network structure was formed, as shown Fig.5(c,d).
When alloy 690 was sensitized at lower temperature, alloying elements diffused slowly, carbides nucleated at dislocation tangle place in grain boundary, they grew up in the direction along the grain boundary, and expanded slowly in grain.
The primary cause was that the grain boundary migration driving force was insufficient in the sensitization temperature range, the grain size was remained basically stable.
When the solid solution temperature increased from 1050℃ to 1150℃, the grain size grew from 12μm to 58μm, the carbide didn’t occur in grain boundary and transgranular area

But various research interests of access contral are still faced with quite a number of challenges.
As to achieve those requirements, we introduce a fine-grained access contral technology (FGAC) for the data-centric business process model.
This paper will briefly introduce the access rights and propose a fine-grained resolution mechanism in data-centric business process model.
Fine-grained access control model Windows and views give a rather coarse grained mechanism for specifying the access rights of participants to the contents of artifacts.
[2] Jie Shi, Hong Zhu: A fine-grained access control model for relational databases.

The initial sample is composed of austenite grains of an average size about 30 µm, and numerous thermal twins with straight and parallel sides are visible.
After HCPEB treatment, craters can be seen clearly at the surface, while the initial grains were subdivided by deformation twins.
The variation in colors indicates a broad spectrum of local orientation within given initial grains.
Besides, the fast cooling of surface melting layer can produce very fine grains.
As a result, the surface microstructure will become finer with increasing the number of HCPEB pulses.

It is evident that in Fig. 3(a) initial grains have been elongated and recrystallization took place at the preexisting grain boundaries.
DRX subgrains were formed along it and marked by number.
It is implied that twinning contributed to recrystallization by expanding DRX grains, that is to say, it helped DRX grains to grow.
While DRX took place along preexisting grain boundaries, DRV carried out in the interior of initial grains.
It helped DRX grains to grow