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It is assumed that the grain boundaries act as sources and sinks for dislocations, while in the grain interior no, or only few dislocations will be stored.
However, there is a strong dependency of the character of the grain boundaries, which is mainly determined by the number of ECAP passes, on the mechanical behaviour of the UFG materials.
As shown by Cabibbo et al. [22] the degree of misorientation changes from mainly low angle boundaries to high angle boundaries with increasing number of ECAP-passes.
The results obtained clearly reveal a strong influence of the number of ECAP-passes on the SRS.
As known from [22], with increasing number of ECAP-passes the misorientation between adjacent grains increase and consequently annihilation processes of lattice dislocations deposited at the grain boundaries will take place much more easily.

Although this method can control the grain size and the location of grain boundaries, but has not attempted any control of GBCD and the grain boundary connectivity which may control the performance of polysilicon.
In the case of polysilicon for solar cell, from the design point of view of the cell we need to specify the geometrical configuration of grain boundaries defined by the grain size and grain shape, in addition to the grain boundary character distribution and the grain boundary connectivity already used to understand bulk properties of polycrystal.
(2) Grain Boundary Microstructure and Directional Grain Boundary Density. ) Grain Boundary Microstructure Analysis by OIM.
It is oly a measure of the density of grain boundaries in a polycrystal, under a assumption of the presence of ideally homogeneous grain structure without any difference of grain boundary character and structure between grain boundaries.
The numbers indicate the fraction of random boundaries for respective data points.

These grain boundaries are often termed non-equilibrium grain boundaries [12].
(a) (b) Fig. 2: Variation of (a) grain size and (b) fraction of HAGB in the gage section of Al – 7 % Si samples as function of number of HPT turns.
As shown in Fig. 3, irrespective of the number of HPT turns, the hardness of the alloy increased with HPT processing.
Fig. 3: Variation of micro-hardness as function of radial distance from the center of the disk with number of HPT turns.
It should also be noted that instances of such transition increased with the number of HPT turns.

There is a large number of theoretical and experimental facts proving that the kinetics of recrystallization, deformation, diffusion, grain sliding, phase transformations, etc is determined by grain boundaries.
Clearly, this method can be convenient for description of atomic structure of grain boundaries in a number of special cases of crystallite misorientations and orientations of boundary planes.
The number of chemical bonds of an atom in this case is equal to 7.
It is possible to classify all grain boundaries by the number of restrictions imposed on the fiveparametrical set of orientational parameters.
The average number of bonds per one atom equals to 4 in a bcc structure.

When silicocalcium was introduced as a deoxidizer at the amount of 1.5 kg/ton (sample # 4), the number of oxisulphides decreased while the number of sulphides in the steel grew by 2.5 times.
In case if aluminum and silicocalcium are introduced simultaneously and at the same quantity of 0.7 kg/ton (sample # 5), a noticeable decrease in the number of sulphides is observed (their amount is the smallest compared with other deoxidation methods) and a small number of oxides precipitate.
Fine globular oxisulphides inside the grain, 500 ×.
A decrease in the amount of oxides and an increase in the number of oxisulphides with a heavier concentration of such a reactive deoxidizing agent as aluminum is accompanied with an equable decrease in the number of sulphide inclusions (samples 1-3).
The dependence of sample contamination with sulphide inclusions inside grains and along grain boundaries on deoxidation method is presented in Fig. 5 It can be seen in the plot that an increase of such deoxidizing agent as aluminum (0.7 and 1.5 kg) results in a higher sulphide concentration inside the grain and, consequently, decreases the amount of sulphides at grain boundaries.

Gallium spots in the unstressed (left) and stressed (right) fine-grained aluminium foil.
Coarse-grained (grain size of 2 to 3 mm) disks of a radius R of 9 mm and a thickness b of 2 mm were prepared by hot pressing of chemical grade NaCl single crystals in a cylindrical mould at 650ºC and annealing at 450ºC during 6 hrs.
The number of wet GB's in each specimen was counted using an optical microscope.
Results and Discussion In the first set of experiments, the number of wet GB's in each specimen was found to increase with increasing load.
The 0,0 0,3 0,6 0,9 0 25 50 75 100 Number of wet GB's (%) Shear stress ττττ , MPa a -0,2 0,0 0,2 0,4 0,6 0,8 0 20 40 60 Number of wet GB's (%) Normal stress σσσσ, MPa b effect of normal stresses manifests itself only at two extreme parts of the histogram (Fig. 3b) where shear stresses are small.

Their maximum grain diagonal size, minimum grain diagonal size, and average grain diagonal size are 90 μm, 11 μm, and 38 μm, respectively.
Although the grain of the third group samples are refined, the grain size varies, and the uniformity of the grains is 2.079.
Although the grain size is relatively high, it does not affect the uniformity of the grains.
When the magnetic field intensity is constant, the value of the saturation magnetic induction increases with the angle of rotation, and the number for the magnetic domain increases.
The grain was refined, and thus, several grain boundaries exist in the microstructure.

Generalization of Fisher Model for periodically non-uniform Grain Boundary V.L.
Kovalevskaya st., 18. 1) vlgap@mail.ru, 2) valerie_kol@mail.ru Keywords: Fisher's model, non-uniform grain boundary and diffusion regime Abstract: The problem of grain boundary diffusion for a case of boundary grain with periodic heterogeneity diffusion properties is considered.
The dimensionless parameters, forming the system of grain boundary diffusion regimes are determined.
Introduction As a rule, the reactionary interaction in boundaries of grains is accompanied with the change of structure of grain boundary (GB).
(6) The "wave number" is determined by expression: 2 V i bi bi bi D pp k D sDδ =+

It is clear form Equ.3 that the impedance of a sample not only depends on its material properties, but also depends on many other items, such as the number of interfaces in the sample, the thickness of different layer, and the exact material properties of every layer in the sample.
For example, controlling the volume rate of doping conductor grain and magnetic grains can adjust the effective electro-magnetic parameters of the composite material.
In this paper the attention is focus on the effect of adding conductor grain into magnetic material, the reason for this is conductor grain can change the permittivity of composite in wide range even the grain volume is very small.
is the grain volume rate, and is a geometric constant which is 1/3 for ball grains..
In calculation the sample thickness is set 0.5 cm and the conductor of grain is 100S/cm.

Keywords: pressure; grain moisture; on line measurement Abstract: This paper presents a grain moisture measurement method based on storage pressure.
The software system using visual programming language, combined with MATLAB, established a grain moisture model, to achieve the measurement on grain moisture.
The typical method for grain moisture measurement is Weight Loss on Drying.
The interface is mainly consists of control window, switches, collected data and real-time graph, in order to control the operation of the instrument, and also includes port, sampling channel number, sampling baud rate, output data path, data bits, reading bytes and other operational controls.
Effect of Grain Moisture Changes on the Granary Pressures [J]