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Comparing to the standard cards, the grain size and the average particle size after the reunion are calculated to 70x200 nm and 100x300 nm, respectively.
So we can find out that if we change the grain sizes, shapes of the semiconductor nano-crystals, or mix them, we could change their optical and electrical properties.
Compared to micron crystalline powder, the grain size of the semiconductor SiO2 nano-crystalline powder is closely related to its the optical absorption coefficient.
We can find out that the optical and electrical are depend greatly on the grain sizes, shapes, and doping of the semiconductor nano-crystals.
Acknowledgments This work was supported by NSFC(Under Grant Numbers: 60877068).

Analysis of Surface Hardness Studies have shown that selective laser melting properties were connected with the grain particle size, grain arrangement, the degree of organization and uniformity defects in the form of other factors.
The internal organization of selective laser molded parts melting uniformly, fine grain size and arrangement law, fewer defects, the higher the performance.
The number and size of No.10 sample pores was smaller, the shape of pores was more regular and most of the holes were circle.
The number and size of No. 4 sample pores were more irregular and arrangement.
There were fewer defects on the No.10 sample from Figure 4, and there was only a small number of pores with smaller pore size.

So grain refinement of the material, chemical stability enhancement and superior comprehensive performance could be achieved due to the role of the nano TiN[[2] Cai Wei, Research on the Structure and Properties of Nano Modified Ti(C, N)-based Cermet and Their Cutting Performance, 2009，30-31 ].
And based on the famous Hall-Petch formula, , the finer the grains, the higher the strength and hardness.
While according to the existing research[[4] Tang Huilan, Research on the Cutting Tool Materials of Ti(C,N)-based Cermets and the Cutting Performance, 2012,22-23 ], the fracture toughness of coarse-grained materials is better than that of fine-grained materials.
The mathematical model of abrasive wear of ceramic materials was obtained by contacting their mechanical properties and wear characteristics: (1) In the formula: V—Wear volume, KIC—Fracture toughness, H—Hardness n—Number of abrasive grains, F—Vertical force on the abrasive grains The material fracture and metastasis are the basic phenomenon of the wear of the cermet cutters.
Grain refinement, because of using nano TiC original powders, leads to the reduction of friction and cutting temperature, shortens the length of contact between the cutter and the chip and prevents the mutual diffusion of the chemical elements between the cutter and the workpiece material in the cutting process[[6] Quan Chaohai, CUTTING PROPERTIES OF Ti(C,N)-BASED CERMET INSERT, CEMENTED CARBIDE, 1997 ].

To decrease the number of experiments, most of the optimization experiments adopted the single factor analysis method [1].
So, the fabrication temperature plays an important role in grain growth and densification of the materials.
At the same time, because the materials OEM8 and OEM5 were fabricated at a longer duration time than OEM3 and OEM1, the grain size of OEM8 and OEM5 is slightly bigger than that of OEM3 or OEM1 as shown in the Figs (a), (c), (e) and (f).
So, the grain size of the materials increases with an increase in both fabrication temperature and duration time, but the effect of fabrication temperature on the grain size of the materials is stronger than that of duration time on the grain size of materials.
Fig.2(f) shows that the microstructure of the material OEM8 is not only more homogeneous than that of the others but also has some trangranular fracture and grain pullout.

Set the average distance between two grains is a, shown in Fig. 4, with the direction of millstone movement, the first particle cut into the spherical at the point A1, then the second particle cut into at point A2, So two same cut marks A1B1 and A2B2 were left on the spherical surface.
In the grinding process, the sand distance is far lower than in coarse, Part of the cutting path formed by adjacent two grains formation overlap, which cause the chip into a sheet (shown in Fig.4(b)), All excess material on the steel roller contact surface has been removed, so that spherical roughness greatly reduced.
So we can let the average grain cutting edge cutting stress to be P, then, for a single particle, the dimension of its suffered grinding force is related with the effect of the actual area of ​​abrasive.
When the wheel abrasive grinding steel ball cut into with, The grinding force Ball can be decomposed to the grinding direction contribute and normal contribute .As the grain cannot form independent cut pits, so its actual chip thickness is related with A1A2.
Let the number of effective cutting edge in each unit area to be j, then d Corresponded to a short arc grinding, which has effective cutting edge.so we can get that the grinding force of any short arc on wheel is （7） Above formula expressed the grinding force of a short arc on the grinding wheel grinding, but the total grinding force is Fn and Ft integral on grinding angle, which value depending on the actual wheel envelope angle .

The tested quantity of thermal activated charges, QTSC, may represent the numbers of migrated zinc interstitials.
Analyzing the structure of Schottky barrier, the charges that constituted QTSC can only exist in the interface of barrier or depletion region of ZnO grain.
The possible migrated ion species in ZnO grain are zinc interstitial ions Zni+ and Zni2+, oxygen vacancies VO+ and VO2+.
Based on the grain boundary deformation model of ZnO varistor (Fig.2), zinc interstitials Zni+ are frozen in the depletion region of ZnO grain after sintering.
They can migrate to the grain boundary under DC electrical field and react with negative zinc vacancies VZn- at interface.

In grain A, there are point defects such as vacancy and mix.
Grain B and C constitute typical low-angle boundary with obvious mix and dislocation.
This is because in the same cutting period, the bigger the cutting speed and cutting distance, the larger the number of deformed workpiece atoms, then the lattice deformation energy increases.
This is because, the increase of cutting depth leads to the increase of processing area near cutting edge and rake face, then the number of atoms sheared and extruded by the tool increase, and the number of atoms moving forward and upward increase relatively, so the volume of chips increases which contacts more closely with rake face.
Of course, the number of atoms sheared and extruded near rake face and cutting edge increases, then the deformation energy stored in workpiece atoms increases.

Firstly we assume Nsc(△V)(cm-3) (in which △V is unit volume of the component ) as the number of short fatigue cracks inside the component, which means the number of short cracks in each cube centimeter and the density field of the component d(x,y,z)g/cm3.
One example to simulate short cracks along crystals inside is presented, whose basic stages are briefly introduced as follows: 1) Starting from the viewpoint of physics metallurgy, 2-D dimensional projections are created to randomly simulate the growth of microscopical tissues of material. 2) Different resistances R are given to different plane such as crystal boundary, small plane and projected plane, where R is a random number denoting ununiformity of material performance. 3) In unit cycle F are assigned to drive force for crack opening in each crystal. 4) Fracture happens when some grain's resistance R decreases to zero, which causes to create and develop a short crack the same size as a grain.
Analysis of Result When single short crack is opening, it's grain size, that's why we cannot see any evidence of cracks, see Fig.4.
But with cracks continuous expansion and its number increasing, we can see its collective effect, see Fig.5 and 6.
So their speed can be measured in according to changes of crack-number-density of short- fatigue-cracks in unit time.

Different grains appear to be coalesced into each other at interface / grain boundary.
Formation of grain boundaries at the point of intersection of growing grains can be easily seen.
In figure 16 (b), there are lesser number of unmelted inoculants, but number of hexagons and rectangles has increased as well as a regularity is observed in their structural evolution.
There are a smaller number of broken hexagons as was the case when inoculant percentage was 0.5%.
Their shape is oval, and they are fewer in number with no coalescence of grain boundaries.

In contrast, the number of publications that reference ARB is just over 1000.
These analyses show a steady growth in the number of intellectual property disclosures protecting SPD methods, equipment, and materials.
Today (October 2010) there are 142 patent disclosures that pertain to ECAP, 59 that pertain to SPD, and 30 pertaining to ultrafine grain metals.
Thus the numbers for patent disclosures referenced above constitute a lower bound.
Varyukhin in: Ultrafine Grained Materials II edited by Y.T.