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When the temperature is lower than 1200°C, the grain was restrained from growing for existence of Nb and Ti, which contributes to grain fining, precipitate strengthening and change of sulfide modality [3].
When the temperature is higher than 1200°C, coarse grain do harm to microstructure [4].
When the soaking time is 0.5s, the grain sizes are quite inhomogeneous because insufficient recrystallization during soaking does the grain refinement.
When hitting intervals are 0.5 and 2s, it is not necessary to consider the grain size due to obvious heterogeneity of austenite grain size (Fig. 3 (1) & (2)).
(1) (2) (3) Fig.6 microstructure of test steel (1→3 corresponding to the Number of tested steel in Table 2) Industial trial.

The multiple microalloy carbonitrides formed in recrystallization controlled rolling and controlled cooling are more conducive than a pure unit microalloy carbides or nitrides to prevent austenite grain growth and grain refinement [4].
The detailed grain sizes are shown in Table 3.
Adding small amounts of Ti element to steel, as long as the cooling rate is fast enough, Ti element will form number of small, stable, dispersed TiN particles, which can effectively prevent the coarsening of the austenite grain sizes.
Adding Ti and Nb to steel also can effectively prevent the growth of austenitic grain after rolling process, and the undissolved or strain induced precipitation of Nb (C,N) can prevent the recrystallization grain.
The grain size of normalizing 2 # test steel contain Ti and Nb is smaller than that of 1# test steel and with a different grain morphology.

Gradient structures have been developed with SMGT, which with gradient nano-grained structures layers, work hardened layer and coarse grain matrix.
For coarse grain iron, all the fatigue cracks were initiated at surface.
The fatigue crack initiation positions were different with different stress amplitudes and, of couse the number of cycles to failure.
Fig. 6 Crack-initiation positions of coarse grains and gradient structures.
So dislocations accumulation is take place nearby the grain boundaries.

In our previous studies [6], we showed that with miniaturization as the specimen size approaches the grain size in plane-strain microbending, the penetration of deformation occurs for coarse grained pins thus producing increased hardening in the middle of the sheet material.
For these experiments, the thickness was varied from 0.25 to 1.625 mm; the process geometries (both specimen and tooling) were adjusted based on the law of similarity so a consistent strain is expected; and the grain size was manipulated through heat treatment to vary the number of grains through the thickness.
The strain graidents through the thickness is less steep with increasingg grain size, producing lower strain values ar the outer surfaces of the sheet for coarse grained structures.
Similarly, Fig. 6b shows that as the grain size increase, the strain profile becomes less steep.
Strain distribution at the bend area through the thickness for a) coarse grained structures and b) 0.5 mm sheets with varying grain sizes.

Using Jiugang hot braised slag as raw material, to determine the chemical composition of the slag with the semi-quantitative analysis and a number of chemical analytical methods.
It’s loose and not binding, with less pore, has a solid dense character and irregular shape. 2 test results and analysis 2.1 grain composition analysis The grain composition of hot braised slag were analysed and determined by screening method.
Tab.1 The grain composition of Jisco hot stew slag Classification standard（mm） 12～15 10～12 8～10 6～8 5～6 3～5 1～3 <1 Content % 2.60 6.57 15.93 20.73 13.70 17.44 11.41 11.62 The tab.1 show that the particle size of hot braised slag is small, less than 15 mm, mainly concentrated in the boundary of 1-10 mm, and the size less than 10 mm accounted for more than 91% of the amount of slag.
(2) Chemical composition analysis In order to determine the chemical composition of hot braised slag, a number of methods were used, the results were shown as the tab.3.
Because ,on one hand ,with the grain size decreasing, the internal structure of steel slag is reduced correspondingly, toughness increased, so that the effect of grinding and crushing decreases rapidly, broking into pieces by the internal surface.

The SEM analysis confirms the formation of nanoparticles by revealing the value of grain size in nanometer range.
The dielectric studies exhibit the Maxwell Wagner polarization and impedance spectroscopy confirms the contribution in conductivity from both grains and grain boundaries at room temperature.
The perfect semicircle is obtained even at RT which shows the presence of conductivity due to both grains and grain boundaries which has been discussed in detail.
The peaks and planes are correctly indexed using JCPDS card number # 34-025 [5].
The Nyquist plots of the samples confirmed the contribution of electrical conductivity from both grains and grain boundaries.

Samples with RE2O3/Al2O3 showed β-Si3N4 as crystalline phase, with grains of high aspect ratio, and a relative density around 99% of the theoretical density.
Specially, the grain morphology of βSi3N4 grains is responsible for the high creep resistance of these materials [3,4].
The creep behaviour of silicon nitride ceramics depends on many factors, such as the amount and composition of the glassy phase, the grain size distribution of the Si3N4 grains, partial recrystallization of the grain boundary glassy phase and oxidation resistance.
Fig. 1b is a typical morphology of 100% αSiAlON materials (SNAN 20), being formed by more equiaxed grains of this phase [3-5].
Almeida's work is supported by the Programme Alβan, European Union Program of High Level Scholarships for Latin America, identification number E03D06378BR.

Mixed thin films exhibit smaller grain size compared to that of pure thin films.
The number of sprays was maintained at 90 for all samples.
Furthermore, average grain size was estimated using Scherrer’s formula [15].
Grain size estimated from XRD patterns shows that Zn/Sn=3:1, 1:1, and 1:3 thin films had smaller grains compared to that of ZnO and SnO2 thin films.
It was confirmed by calculation of average grain size by XRD.

Analyzed the pulse impact force of non-viscosity debris flow testing results by wavelet denoising method, the testing conditions are A-3(whose grain size is range from 0.3cm to 0.8cm), B-3(whose grain size is range from 0.8cm to 1.5cm) and C-3(whose grain size is range from 1.5cm to 3.0cm),all of whose solid phase ratio are 0.16.The analyzing results show that the denosing effect adopting Db5 wavelet function is superior to ones adopting Sym2 wavelet function, meanwhile, the denosing effect adopting hard threshold method is superior to ones adopting soft threshold method.
Aiming at this experiment, 5 solid phase ratios (the solid phase grain’s volume takes up the total non-viscosity debris flow) and three groups of solid phase grains are studied out, then, 15 conditions can be combined, and they can be seen in table 1.
Because there are a large numbers of testing date gained in the experiment, thesis takes three testing conditions (A-3, B-3 and C-3)as example to analyze the wavelet denoising problem of non-viscosity debris flow’s impacting pulsating load, and the testing results are shown in figure 2 to figure 4.
The result of laboratory impacting test shows that the grain size of solid phase affects the impacting pulsating load signal remarkably, and the bigger the grain is, the bigger the SNR is.
Thirdly, the sensitive experiment shows that the impacting pulsating load signal is affected evidently by the solid phase’s grain size, the bigger the grain is, the bigger the SNR is, and the better the denoising effect is.

The average grain size varies from 10 nm to 15 nm after annealing.
The most important advantage of the nonmagnetic matrix encapsulated is the increase of the effective distance of neighboring magnetic grains so that the inter-grain exchange coupling can be weakened or eliminated.
Since this clustering structure was caused by the exchange coupling among a number of grains, the weak and small isolated clusters are due to the significant reduction of the strong exchange coupling among these gains.
The average grain size varies from 10 nm to 15 nm after annealing.
This is because, at annealing 400 °C, more C atoms were segregated into the grain boundary, and the hcp-texture of magnetic grains is improved and intergrain interaction is decreased.