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Recently, much importance was attached to synthesis and characterization of nanocrystalline iron nitrides for their unique magnetic properties and improved performances determined by the smaller grain/particle size, surface structure and inter-particle interaction[10-15].
A careful calculation, based on the (200) diffraction peak of its XRD pattern, gives its lattice parameter = 2.870 Å, corresponding to the standard value a = 2.876 Å of Fe-Cr (Card number: 34-0396).
Besides, from the half-width of XRD peaks of the powder samples (shown in a of Fig. 1(b)), the grain size is estimated as 50–80 nm for nano-crystalline (Cr,Fe)N.

It can be due to that specific surface area of pore forming agent with the small particle size is large and the particle number is more than those with large particle size.
When it mixed with alumina powder, it can be used as fine grain skeleton to fill in pores and increase the grain bulk density due to relatively high homogeneous mixing degree.

In this sea region the sediment concentration in winter is higher than the one in summer, which may be due to the increase of the seaward sediment carried by strengthening of the southwest alongshore current from the Pearl River. 1.4 Sediment Grain Size According to the analysis of the measured data it is found that the suspended particles are quite even in this sea region.
The grain size of the bed material on the tidal creek in the bay is slightly larger and thus the material is of fine-medium granular sand (d50=0.272mm, 0.208mm).The sand on the tidal channels at the mouth is of medium coarse sand and the medium diameter is 0.540mm.
In project C, an annular harbor basin is planned on the shallow beach to the west of the mouth to substitute the function of training dike and increase the number of wharfs.

Properties of the Obtained Porous Si3N4-SiO2 composites Sample Numbers Porosity Thermal conductivity [W/m·K] Compression strength [MPa] S-D1(Sol-gel+Freeze-Drying,1200 oC) 64~80 0.08-0.1 15~17 S-D2(Sol-gel+conventional drying, 1200 oC) 58~63 0.11-0.13 16~17 S-D3(Sol-gel+Freeze-Drying,1300 oC) 60~73 0.1-0.12 20~25 Results and discussion Phases analysis.
It was found that two kinds of pores appeared in the specimens , one is the larger open pores with pore size of 1~5 μm in grain boundary and the porosity is about 20%~30%; The other, closed pores, is the nanometer level in the grain with pore size, and the volume is more than 50%.

Table 1: Compositions with substitution of quartz by POFA (wt %) Mix Number Clay Feldspar Quartz POFA AF1 50 25 25 0 AF2 50 25 20 5 AF3 50 25 15 10 AF4 50 25 10 15 AF5 50 25 5 20 AF6 50 25 0 25 Results & Discussion X-Ray Fluorescence (XRF) analysis is proficient in analyzing material contents inside POFA, hence the amount of SiO2 can be observed.
As seen from the figure, the grain sizes were big due to fine matrix of decomposed of clay, feldspar, and quartz minerals (Fig. 2a) and the microstructure were changed from a matrix with irregularly shaped interconnected pores to a more compact matrix (Fig. 2b).
Influence of the grain size of alumina in the glaze of fast-fired porcelain tiles.

Research in natural fibres, such as sisal, coconut, flax, jute, hemp, bamboo, wood, palm fibres, straw, and their possible application in and outside of civil engineering is being carried out by a number of experts worldwide, e.g.
As an aggregate, lightweight expanded glass with grains sized 0.25‒0.5, 0.5‒1 and 1‒2 was chozen and also expanded perlite, grain size 0.315‒2.5.

Momentum equation for the mixture can pass through the all phase momentum equation and obtain their demand, can be expressed as: (2) (3) Wherein, n is the number of phases,is the volume force, is viscosity of mixture, is drift velocity of phase k.
As can be seen from the Fig.6, the separation efficiency will increases with imported grain size.
At the same time, the two curves in figure, also can see: the average import grain size at the same time, the dispersed phase (oil) density for the separation efficiency is 0.82kg/m3 high than density 0.86kg/m3, visible separation of oil phase density smaller more conducive to cyclon.

However, Cotterell's approach suffers from the limitation that it requires large number of identical specimens with varying pairs of identical notch lengths at two edges inducing variation in ligament lengths.
Standard metallographic technique of grinding and polishing up to 0.25 µm diamond finish followed by etching using Marshall's reagent was employed to reveal the microstructure and to estimate the average grain size.
The microstructure exhibits ferrite grains with average size of 12.38 +0.27 µm.

This quasi-brittle behaviour is due to the existence of a number of different types of toughening mechanisms that shield the growth of the crack inside the fracture zone.
The refractory ceramic is composed of alumina (Al2O3, 56 wt%) and mullite (3Al2O3 · 2SiO2, 43.5 wt%) grains, with a crystalline phase present at the grain boundaries and some traces of iron oxide (Fe2O3, 0.1 wt%) [7].

When increasing the charge to 2C, the Sn grains increase and begin to show a tetragonal crystal shape while the pore size reduced a little (Fig. 2b).
The Sn grains also grow over 200 nm with a clear tetragonal structure.
With the increase of cycle number, the charge and discharge plateaus are becoming less obvious, which indicate the capacity loss with cycles.