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However, at strength levels above 1100MPa, the practical application of these materials has been limited by their ductility, which is controlled by the grain size and the morphology of the precipitated alpha phase in grains.
Simultaneously, sphere α phase is well-distributed in the grain, and the number of it was not large.
It has transformed to aciculiform neither maintaining sphere meanwhile the number of α phase increase a lot and α phase become larger (Fig. 1(c)).
With the temperature increased, the shape of the α phase changed and the size became larger, but the number of it decreased.
The more the number of vacancy was preserved, the faster the atom aggregation fields formed.

Fig.2 Synthesis of axial ultrasonic vibration velocity for a single grain The loading condition of single grain can be obtained when the inner hole of the honing workpieces is expanded as shown in Fig. 3, where assumes that the oilstone abrasive whose apex angle is 2φ and is uniformly distributed along the oilstone surface.
In this paper we only consider the self-excited vibration of the single grain caused by the change of dynamic honing thickness in the x and z directions.
Figure 4 shows the single grain cutting model in the space coordinates oxyz, and dynamic honing thickness of the oilstone is calculated as:
It assumes that the contact form between oilstone abrasive grains and the workpiece is linear, and the effective number of the abrasive grains distributed uniformly on the contact axis.
It is assumed that the flutter frequency is , and k is the multiple of flutter ripple, which is the number of lobes in stability limit diagram.

Due to the existence of a large number of covalent bond Si-N and low diffusion coefficient, the Si3N4 sintering is very difficult.
The relatively small β-Si3N4 grains can be observed in the SN1 sample, and the microstructure with elongated β-Si3N4 grains well interconnecting were obtained in the other samples.
Yb2O3 has been found to be effective as a sintering aid in accelerate the elongated grain growth of β-Si3N4, which strengthen the effects of grain bridging and pullout to improve the mechanical properties [13,14].
What we all know that the higher aspect ratio β-Si3N4 grains, the higher strength of Si3N4 ceramics can be obtained.
In most specimens, the microstructure exhibited many large, interlocking elongated β-Si3N4 grains.

Horn: Also called ultrasonic Journal Title and Volume Number (to be inserted by the publisher) 641 amplifying pole.
Analysis of Grain Grinding Performance Through analysis of efficiency ultrasonic honing motion, grain cutting motion in axial vibration honing has become very clear.
In order to analyze grain performance of oilstone, axial ultrasonic vibration cutting is taken as an example.
It is thus evident that oilstone’s dynamic stress 
m added by ultrasonic vibration is close to its static collapsing stress 
b, which increases the autogenous grinding of grain.
Ultrasonic honing sharpens grain, which is favorable for raising cutting efficiency. 2.

The relative lower operation temperature of SOFC has a number of benefits, including cheaper materials, lower degradation problems, less thermal mismatch and closer temperature match for internal reformation possibilities, etc.
AC impedance technique is one powerful tool to separate the contributions of the lattice and grain boundaries from the overall resistances of solid ionic conductors.
On account of the different compositions of grain boundary phases, different Gd 3+ and/or Y 3+ doping level results in different grain interior conductivity.
The Rgb/(Rg+Rgb) ratio denotes the contribution of grain boundary resistance to the overall resistance.
Since the contribution of Rgb is neglectable, the total electrical conductivity equals to grain interior conductivity at temperature above 550 oC for all samples.

A large number of studies have shown that the work-hardening in the surface affects the micro-cracks and corrosion inside the material, which has a larger impact on the service life of the part.
Cutting tool is solid cemented carbide flat end milling cutter with TiAlN coating.The diameter is 16mm and the number of teeth is 2, the helix angle is 30º.
From the standpoint of dislocation theory, the new slip bands generated in the grain boundaries in the deformation region of the metal.
The upper is hardening metamorphic layer with broken and distorted grain as well as fuzzy grain boundary which is difficult to distinguish.
Based on the dislocation theory, the heterogeneity of the degree of such deformation is due to the different orientation of the crystal grains, so the slip order is not the same.

Because of the high number of cutting edges, the loss of single grains can be compensated in part.
Apart from that, the kinematic cutting edge spacing and thus the number of active cutting edges increase with higher feed values, leading to the higher process forces.
The values dispersion is much higher compared to the grain size D301.
The surface quality can considerably be enhanced using the smaller grain size.
It leads to an strong influence of the chosen feed rate, which should be limited to f = 0.06 mm/rev in case of the D126 grain size and f = 0.1 mm/rev for the grain size D301, respectively.

During 2012-2013 a number of field studies have been carried out designed to elucidate conditions under which mud and silt carried by the river are formed, their volume, grain-size composition, and nature of their accumulation over 50 years of the Khachen reservoir operation.
In the presented developments data on water and silt flows, actual coordinates of the Khachen reservoir bottom and the banks and grain fineness measurements have been used.
Fluid and suspended average monthly loads and the size of annual streamflow discharge Monthly stream-flow I II III IV V VI VII VIII IX X XI XII Annual Streamflow discharge, m3/s 1,32 1,53 3,12 6,59 7,63 7,66 4,62 2,48 2,71 2,81 2,24 1,58 3,69 Sediment load, kg/s 0.013 0.017 0.03 0.288 0.704 0.636 0.308 0.100 0.057 0.030 0.023 0.010 0.185 Bed load observations are not commonly undertaken owing to difficulties encountered the sufficient quality of such works; however, number of extensive observations and research studies were conducted by the Georgian scientists in late 1970s.
Volume of accumulated sediments in the Khachen reservoir Layer number 2-2 3-3 4-4 5-5 6-6 7-7 8-8 9-9 Distance from dam (m) 170 350 550 700 900 1200 1500 1800 Length of layer, (m) 180 200 150 200 300 300 300 Layer surface, (thousand m2) 2.76 2.48 1.20 0.83 0.97 0.41 0.17 0.08 Volume of accumulated sediments (mln m3) 0.472 0.368 0.135 0.18 0.207 0.087 0.037 Total volume (mln m3) Comparison of the three values of the accumulated sediments volume in the reservoir reveals that the actual degree of the accumulated sediments is much higher with reference to the estimates based on hydrologic calculations and hydrometric measurements.
Number of downpours at similar magnitudes may have been occurred over 50 years.

It was observed that not only microscopic pulverization but also nanoscopically fine-grained crystallization occurred in degraded particles.
Fig. 3 shows TEM images where the particles degraded under CO/H2 were fine-grained, amorphized and/or strained rather than those under H2.
Fine-grained and strained structure was observed nanoscopically only in the sample tested with CO/H2.
However, it could not be identified yet where CO occupies in the degraded sample grains.
Fig. 1 Degradation of cycle hydrogen capacities of V75.5Ti10Cr11Mn2Ni1.5 (left) and Ti1.01Cr1.49V0.30 (right) by using H2 and CO/H2. 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 0 200 400 600 800 1000 Cycle number, N /cycle Cycle hydrogen capacity, H/M H2 CO/H2 0.0 0.2 0.4 0.6 0.8 1.0 1.2 1.4 0 200 400 600 800 1000 Cycle number , N /cycle Cycle hydrogen capacity , H/M Initial activation （H2） Cycle test （H2） Initial activation （CO/H2） Cycle test （CO/H2） CO/H2 H20 100 200 300 400 500 600 700 Temperature, T /deg.

For BCC crystals, the number of the slip systems, N, is 48.
The nonlinear evolution rule for isotropic hardening in each grain can be coupled with an interaction matrix , i.e., (7) where t0 is the initial shear yielding stress of each slip system.
The local stresses and strains can be obtained through an explicit transition formulation, i.e., (12) (13) where denotes the local stress of the grain g, and denotes the global uniform stress.
In the simulation, an aggregation of 40 randomly oriented single crystal grains is employed to represent the polycrystalline steel, which is proved to be effective by [3].
For the two load cases, the applied peak stresses of the cyclic loading are both lower than the upper yielding stress of the steel (about 360MPa), but higher than the lower yielding stress, (about 315MPa), and then the ratchetting only occurs after a certain number of cycles.