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During the process of grain growth, there are both grain boundary diffusion and grain boundary migration.
Only those grains with the size of YSZ nuclei d≥dc will grow in the later grain growth steps.
Therefore it is necessary to hold a period of time (e.g. 2h) at about 1000°C, which helps to form a large number of nuclei with size larger than dc [18,19].
The grain growth is associated with grain boundary motion, which is mainly controlled by grain boundary migration in higher energy state.
As we know, the grain growth behavior contains two processes: grain boundary diffusion and grain boundary migration.

The observed enhancements in magnetic properties can be attributed to the exchange spring mechanism between the soft and hard magnetic phases, as well as the larger grain size in the samples, which promotes a greater number of magnetic domains and reduction of the grain boundaries.
The average grain sizes are 1.69 mm for NdFeB and 3.90 mm for NZF.
The average grain size for all the composites is shown in Table 2.
Larger grain size contributes to a higher number of magnetic domains in the samples with a lesser fraction of grain boundaries, thus the magnetic domain wall displacement will be easily moved with the magnetic field direction, contributing to better magnetic properties.
Additionally, the larger grain size in M1 samples typically correlates with a greater number of domain walls within the grains.

Al3Zr particles which are coherent with the matrix would inhibit the movement of dislocation induced by stress and also the migration of sub-grain boundary and grain boundary induced by thermal activation.
In these conditions, unshearable Al3Zr particles contribute to the piled-up dislocations at the grain boundary of the occurrence of the strain induced grain boundary migration during recrystallization.
The results show that a large number of Al3Zr particles had been precipitated in the alloy (Fig. 1 a and c).
After the D treatment, a large number of small size and dispersed Al3Zr particles were precipitated.
A greater number of subgrains cause the alloy grain size to decrease.

This experiment was conducted to evaluate the effect of ensiling on fermentation quality and aerobic stability of a total mixed ration (TMR) containing wet brewers’ grains and corn straw.
The number of lactic acid bacteria (LAB) for the TMR decreased from the initial 3.2×103 cfu g-1 to below detectable levels and yeast counts increased by 1000 times.
The numbers of LAB, yeast and mold in fresh TMR and TMR silage were counted by the method of Cai et al. [8].
Microbial measurement Fig. 2 shows changes in numbers of LAB, yeast and mould during ensiling.
The number of LAB increased quickly from the initial 3.2×103 cfu g-1 at day 0 to 1.6×107 cfu g-1 at day 3, then it reached slowly up to day 7.

The grain structure exhibits in this case bands and also large pancake like grains in the center as well as at ¼ of the thickness.
According to the complexity of the microstructure across the thickness the grain structure have been characterized by the parameter T = L / N for the bands, L is the length of a band and N gives the number of grain boundaries intercepted.
For more or less equiaxed grains a mean grain size d was determined by linear intercept method.
We see finally bands, pancake like grains, and in the surface region small grains.
One obtains grain growth in the surface region.

It was found that the anti-oxidation effect is increased by Ce4+ modifying and with increasing layer number.
As shown in Fig. 2, the weight gain increases with the increase of temperature and decreases with the Ce 4+ addition and the increase of film number.
It can be concluded that the steel matrix is directly oxidized along the grain boundaries; and the oxidation gradually develops around the grains.
With the increase of film number, the protective effect increases.
The thicker film can effecttively retard the formation of holes and depress the oxidation around the grain boundaries.

Although the Linux system has a number of security mechanisms, such as identity and authentication mechanism, file access control mechanism and capacity mechanism, there are still security flaws.
The ACL can control any single user, ACL’s file access control is more detailed, fine-grained.
The structure also contains a number of auxiliary fields, for the quick search of subjects or objects. 5 CONCLUSION In this paper, we researched the access method of Linux files, and studied the Linux Security Module (LSM).
LSM can not deal with the issue of fine-grained access.
So the paper designs a mechanism for fine-grained access called ACL.

This is because the α grains of the equiaxed are smaller, and the grain refinement improves the very high cycle fatigue performance [10].
The Widmanstatten is rough as a whole, with a large number of fracture steps, and the bimodal and equiaxed are relatively smooth.
The grain refinement effect makes the fatigue performance better.
Acknowledgement This research was funded by the National Basic Research Program of China (973), grant number 2015CB057400.
Diversity of damage evolution during cyclic loading at very high numbers of cycles.

Introduction Grinding usually can produce excellent surface finish due to a large number of abrasive grains which simultaneously engage in cutting.
In optimization of wheel surface topography to improve grinding efficiency, Aurich et al.[7] conducted simulation of grain distribution on an electroplated wheel.
Although a certain amount of research works has been reported on the development of new grinding wheels by using new types of abrasive grain and performing grain distribution optimization, very few papers have been found on developing a new wheel or tool which can combine the advantages of conventional wheels and cutters.
However, due to the smaller number of cutting edges, the surface roughness obtained by cutting tools is relatively worse than that by grinding wheel.
Acknowledgements The authors sincerely thank the research supports from the Chinese National Natural Science Foundation (Grant Number: 50875225 ) and from the Science and Technology Department of Hunan Province(Grant Number: 2009GK3166).

It is based on extruding material through specially designed entry and exit channel dies to produce an ultrafine grained microstructure.
Introduction To date severe plastic deformation (SPD) processing is regarded as a new promising method of manufacturing bulk specimens having ultrafine grained (typically defined as an average grain size less than 1 µm) microstructure of superior mechanical properties in achieving strength, ductility and superplasticity [1-5] at the same time.
The SPD processed materials show not only the unique physical and mechanical properties inherent in various ultrafine grained and nanostructured materials but also a number of advantages over nanostructured materials manufactured by other methods through powder and thin film processing.
In order to optimise the control variables and obtain the ultrafine grained materials with a good quality from coarse grained materials using ECAP, it is essential to combine experimental research with a theoretical analysis of inhomogeneous deformation behaviour of the workpiece during the process.
Geometry channel angle, corner angle, workpiece (shape, length, width, thickness, radius), dies Material elasticity, yield stress, strain hardening, strain rate sensitivity, anisotropy, ductility, history, microstructure Control Variables Processing speed, friction, back pressure, temperature, pass route, number of passes, ejection Internal Parameters stress σ, strain ε, strain rate ε& , dislocation density ρ, cell size d , cell wall volume fraction f , misorientation angle θ Success geometry, microstructure, mechanical properties, homogeneity Results Failure fracture, size inaccuracy, residual stress, grain growth, low strength, low ductility, high pressing load, dies problems (wear, fracture, deformation) Fig. 2 Examples of failures in workpiece and tool.