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Table 1 ingredient of Al2O3 ceramic s [wt.％] Number Al2O3 Nb2O5 CAS 1 99.8 0.2 2 99.6 0.4 3 99.4 0.6 4 99.2 0.8 5 99.8 0.2 6 99.6 0.4 7 99.4 0.6 8 99.2 0.8 9 99.2 0.6 0.2 10 99.0 0.6 0.4 11 98.8 0.6 0.6 12 98.6 0.6 0.8 Detecting methods.
With the increase of CAS, plate grains appear, and columnar grain is obviously reduced (Fig.4c).
During the grain growing, Fig.8 is the growth model of columnar grain in manner of squeezed liquid phase.
Smaller grains attach to bigger ones via liquid diffusion, and liquid phase is pushed to the grain side, bonding bigger grains into columnar ones. 4.
Zhu: Transactions of Nonferrous Metals Society Vol, 18(2008), p. 388 a) Bamboo shape columnar grain; b) Squeezed liquid phase; c)Bonding and diffusion of grains; d) Columnar grain Fig.8 The grain growth model of a columnar grain b) c) d) 160nm a)

Thus, the grain growth under the specimen sputtering process may also be another reason that cause the elongation of grains.
Based on the calculation of stereology, the calculated average number of 14 is in a fine accordance with the average number of grains within one island, which is computed to be (26/10.6)3=14.8.
(c) Plot of the number of grains inside islands versus the ESD of individual islands.
The average number of grains within individual islands is 14.
The radius of the smallest segmented grain is 1.7 nm

(1) In this numerical model, nucleation site i for one kind of precipitate was assumed in the matrix (i=1), dislocations (i=2), grain face (i=3), grain edge (i=4) or grain corner (i=5) as illustrated in Fig.3.
Dislocations and grain boundaries (grain face, grain edge and grain corner) serve hetero- geneous nucleation sites, whereas homogeneous nucleation is assumed in the matrix [1].
Here, ni, Ci and Vi are the number, solute concentration and volume fraction of vacant i sites, whereas those with overline refer to the equivalents of occupied i sites by precipitates.
Results of numerical modeling Fig.4 shows the changes of number density N(__)i and volume fraction V(__)i of precipitates nucleated at site i as a function of aging time t at 443K.
(a) (b) (c) 1 3 4 5 1 3 2 1 3 1 3 2 4 5 2 3 4 5 3 4 5 2 1 Fig.4 Aging time dependence of number density and volume fraction of precipitates nucleated at different sites at 443K.

In the present study, controlling conditions in hot rolling such as temperature, total number of passes, reduction in a pass, etc. have been investigated in a Zn-Al eutectoid alloy to obtain fine-grained microstructures.
Therefore, in the present study, control conditions in hot rolling such as temperature, total number of passes, reduction in a pass, etc. have been investigated in a Zn-Al eutectoid alloy to obtain fine-grained microstructures.
Degree of grain refinement was assessed with average grain size.
The average grain size tends to increase as the process proceeds (with increasing number of pass) within the range from 1.4 to 1.9mm.
Number of passes, N 1.2 1.4 1.6 1.8 2 5 6 7 8 9 10 Average grain size, L/mm Fig. 3 Effect of number of passes on average grain size References [1] Y.

If grain size is 1µm and dislocation density is -2 12 -2 1 m (10 m ) µ , the number of dislocation lines contained in a grain is approximately one.
When the number of dislocation lines contained in a grain is sufficiently small in the initial state, slip deformation of a crystal hardly occurs and critical resolved shear stress increases.
While, the number of dislocation lines contained in a fine-grain changes depending on grain size, even if the dislocation densities are the same value.
Assuming the number of dislocation lines, which is necessary to start slip deformation as a usual metal, to be constant regardless of grain size, the value of ( ) k α ρ increases with decrease of grain size.
Yield behavior of fine-grained metals depends on the initial grain size and the initial dislocation density.

If the sample contains large gains, either large average grain size compared to the beam size or some extreme large grains mixed with fine grains, the measured diffraction profile will not produce an accurate 2q peak position.
With some extreme large grains, even the average grain size is fine, the high diffraction intensity from a few large grain may shift the peak position significantly.
In the weighted linear least squares method, the weight of a data point on the diffraction ring is proportional to the diffraction intensity, which is directly related to the number of participating grains.
First, this will increase the number of available data points for stress calculation so as to improve the sampling statistics.
By using multiple diffraction rings, it is also possible to reduce the number of sample tilt angles without reducing the angular coverage.

(1) (2) Where, D — the equivalent diameter of primary silicon grains; FS — the shape factor of primary silicon grains; A — the area of a primary silicon grain; N — the total number of primary silicon grains; P — the perimeter of a primary silicon grain.
As a result, a large number of primary silicon nuclei can be formed and a part of them may grow up along the inner wall surface.
Therefore, a large number of small primary silicon crystal nuclei or grains can survive in the slurry.
If a large number of primary silicon grains appear in the Al-25%Si aluminum silicon alloy slurry, the distance among the grains may be very much small and the mutual interference in the solute field and the temperature field can inhibit the excessive growth of the primary silicon grains, which makes the primary silicon grains significantly fine.
Apart from the pouring temperature, the curve number of the used serpentine channels also affects the equivalent diameter of the primary silicon grains in Al-25%Si aluminum silicon alloy slurry.

Fatigue crack initiated from specimen surface, when number of cycles to failure was shorter than 106 cycles.
(b) indicate typical coarse grains.
The MDFed Ti is composed of homogeneous ultrafine grained microstructure with the average grain size of 200 nm.
Figure 2 indicates the relationship between stress amplitude, σa, and number of cycles to failure, Nf, in the fatigue tests, called S-N diagram.
Surface crack initiation was also recognized in the MDFed Ti, when number of cycles to failure was shorter than 106 cycles.

Fig. 1 Gravels in conglomerate layer Statistical Analysis of Grain-size Characteristics of Gravel Statistical Method of Gravel Grain Size.
This paper divides different particle sizes of gravel into grain groups, and statistics and analysis of the quantity, volume and their percentage of each grain group are carried out.
Table 1 Statistical Summary of Gravel Grain Size group quantity percentage（%） volume percentage（%） cumulative quantity percentage（%） cumulative volume percentage（%） <30mm 32.99 3.97 32.99 3.97 30-40mm 21.01 10.00 54.00 13.97 40-50mm 20.08 15.78 74.07 29.76 50-60mm 10.13 13.05 84.21 42.80 60-70mm 4.37 7.63 88.57 50.43 70-80mm 3.86 9.71 92.43 60.15 80-90mm 3.46 11.98 95.89 72.13 90-100mm 2.78 13.81 98.66 85.94 >100mm 1.34 14.06 100.00 100.00 total 100.00 100.00 Fig. 3 Quantity and volume percentage Fig. 4 Cumulative quantity and volume percentage From the Fig.3 we can see that the number of 30 mm below is the largest and the number of more than 100mm is the least.
The number of 30-40mm and 40-50mm size is about one fifth of the total quantity respectively.
This paper divides different particle sizes of gravel into grain groups, and statistics and analysis of the quantity, volume and their percentage of each grain group are carried out.

However, the number of the precipitates at the grain boundary in the Cu-added and Ge-added alloys is smaller than that in the binary alloy.
These dislocations increase in number as the number of repeated loading cycles increases.
The number of the precipitates on the grain boundary in the Cu-added alloy or Ge-added alloy is smaller than that of the binary alloy.
Therefore, the increase of the fatigue strength in Cu-added alloy or Ge-added alloy is mainly attributed to the number of the precipitates on the grain boundary in Cu-added or Ge-added alloy decreased than that of the binary alloy.
The number of the precipitates at the grain boundary in the Cu-added or Ge-added alloys is smaller than that in the binary alloy.