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The Fig.4(a) indicates that the matrix and Si3N4 are combining well and the wisher distribution even，the wisher is wrapped tightly by Si3N4 and aluminum phosphate grains, the wisher and grains form integral network structure through the process of sintering.
A number of Si3N4 are get to amorphous silica, of witch fill the gap.
Though the wisher is still extracted and unstuck, the transferred load capacity of the interface is reduce，the grain grow at the same time，so the dielectric properties of composites are lower at this sintering temperature.

The grains are of almost similar sizes owing to the similarity in processing cycle.
The grains have spherical morphological features.
Grains sizes varies from 3μm to 5μm.
There are number of piezoelectric parameters which can be measured.

Theory and methods of study A number of hypotheses have been proposed to explain the formation of a loading layer and a loss of diamond wheel cutting capability in grinding [12, 13].
Results The results of optical analysis of the specimens have revealed that the diamond wheel efficiency reduces during the first minutes of machining high-strength materials, and after 30 minutes diamond grains on the surface of the wheel are almost completely covered with a loading layer (Fig. 1), which leads to a need for its replacement or additional periodic dressing.
The analysis of the spectrum (Fig. 2) of a point near the diamond grain has revealed that the loading layer consists of about 40% of tungsten W and 3% of cobalt Co by mass which are part of the treated material.
This layer completely covers the grains and prevents them from renewal during machining.

It is magnetically classified in a weak ferromagnetic group at room temperature; however, it is very significant if the magnetic property of the hematite can be improved up to the degree that corresponds to the magnetic property of ferrite materials without doping any elements having low Clarke numbers.
Templated grain growth and hot/sinter forging are well-known techniques to fabricate textured polycrystals but these methods require large, single-crystalline seed particles for abnormal grain growth during sintering.
It was observed that the orientation of hematite was improved by heating, and a completely c-axis-textured microstructure with the Lotgering factor, which is an index of the degree of c-axis grain alignment [8], F=1.0, was accomplished at 1200 °C.

There are number of routes which can be used to produce rapid solidification, including spray methods, weld methods, and chill methods.
There are number of routes which can be used to produce rapid solidification, including spray methods, weld methods, and chill methods.
As solidification rate increases, grain size decreases because there are more dispersed particles formed and they are finer.
Hence, the strength increases due to finer dispersoids strengthening mechanism (particle size is less than 1μm) which will impede grain boundary movement.

Because the number of construction generation soils has increased.
Introduction Recently, an increase of the earth and sand generated from the construction site is a problem, and the number of low quality soils such as the soft soils and cohesive soils keeps especially increasing.
Therefore, it is thought that it is possible of the fill of high fills and the rapid ascent if reinforcement material is inserted in the rough grain soil layer of the sandwich method.
Moreover, it is thought that it is also possible to thin the thickness of the rough grain soil layer if reinforcement is appropriately arranged.

It is concluded that nucleation and growth of great number of radial and axial cracks and lateral cracks play dominant role in fractured ceramic target under impact loading.
(a) t=0µs (b) t=3µs (c) t=7µs Fig.5 Failure characteristic of the first alumina sample Fig.4 Hugoniot curves for AD90 alumina Micro-cracks nucleate either at in homogeneities such as inclusions, grain interfaces, glass phase and reinforcements or at defects such as micro-cracks, and pores within the sintered ceramics under dynamic loading.
It is stochastic for the development of cracks due to the random orientation of the grains and the formation of a second phase at some interfaces.
It is concluded that nucleation and growth of great number of radial and axial cracks and lateral cracks play dominant role in fractured ceramic target under impact loading.

Generally, in ZnO, electrons are promoted from the valence band and transferred to the conductance band under illumination that provides no less than the band gap energy of ZnO, leaving the corresponding number of holes in the valence band to form electron-hole pairs.[5] Photocatalysts oxidize organic polymers by adsorption holes.
Figure 2(b) shows the average grain size of the ZnO samples made from precursor solutions of different pH values, computed by the Scherrer formula.
The grain size is calculated to be about 20~30nm, comparable to the SEM results shown in Fig. 1.
It is well known that he pH value is the main influence on grain growth during the sol-gel process.
In connection with micro-structural characterization and natural photocatalytic degradation, the effect of the precursor solution’s pH value on the catalyst mainly depends on the changes of carrier mobility associated with grain boundaries, and the grain boundaries affect the particles’ size and activity.

Whereas nanocrystallization seems to improve the oxidation resistance of many Zr-based metallic glasses, a coarse crystalline structure exhibits fast oxidation along grain boundaries, at least in Zr2Pd.
Oxidation of Zr-based metallic glasses has been studied recently in some detail in a number of papers [13-16].
Cross-sectional microscopy, however, reveals as shown in fig. 4 that large crystalline grains are very stable against oxidition, but fast oxidation proceeds preferrentially along the grain boundaries.
These results clearly indicate that grain boundaries in nanocrystalline material behave quite differently than in the coarse alloys.
It is not known why the grain boundaries in a nanocrystalline structure do not behave in a similar way.

Search for other FSMAs led to appearance of a number of different compositions and manufacturing techniques.
The relatively high deviation is associated with a rather significant difference in grain size of the alloy both in the sections parallel to BD and perpendicular to BD.
Inside the molten pools, close to their surfaces, more equilibrial cooling conditions take place resulting in larger grains formation.
In the junction zone of the molten pools, there is a third type of grains - practically equiaxial fine grains with the size of about 5-10 mm.
The second group includes coarse grains close to an equiaxial state with the size of 40-80 mm and the aspect ratio of 1.8-2.5.