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Increasing the annealing temperature increases also the grain size of the ferrite, which is in concordance with the results of N.
XRD patterns of the four heat-treated doped garnets The morphology of crystal grains of the Al doped yttrium-iron garnets, with different amounts of aluminium was studied by SEM and the results are shown in Fig. 5.
When the aluminium content increases not only the pore diameter will be changed, but number of the larger pores will be decreased too.

From the point of view of electromagnetics, such a highly inhomogeneous material becomes difficult to predict due to the fact that currents can flow only through well connected paths, and the effect of the magnetic field depends strongly on the type and the distribution of defects or grain structure.
Down: corresponding magnetic map number proportional to the average of the field over the surface of the sample: [] ∫∫ −=− dxdyHyxB S HB z 0 0 ),( 1 µ µ (1) where S is the area of the surface of the sample.
From the current maps we can distinguish the critical current in the joint, Jc GB, and the current in each grain, Jc G , the ratio Jc GB/ Jc G is the figure of merit of the weld it is of 0.7 for sample A and 0.96 for sample B.

With the well depth increase and downhole condition more and more complex, the buttress premium thread connections with great joint strength and good sealing property had been developed out successfully and were used in a great number of oil fields [3-4].
The grain size is grade 9.5 and the inclusions of material are A0.5, B0.5, D0.5.
Crack is easy come out at the interface between wide ferrite batten in upper bainite and fat carbide that locate between ferrite battens, and it is impossible to prevent crack extending under the role of small grain boundary, so the ductility of material is cut down by this bad structure.

Each thermocouple is numbered from 1 to 7 as shown in Fig.1 (a).
Many pinholes appear for Ni film and the grain size expands for Cu film [8].
Since the electrical conductivity or resistivity depends on the mean free path of electron or relaxation time for electron, pinhole or large crystal grain seems to affect the electrical property.

This problem of crack closure becomes more serious in the case of back-wall cracks in thick-walled structures, especially in the welded regions, as the large scattering noise from the grain boundaries of the weld metals decreases the accuracy of the evaluation drastically.
Therefore, DCPD technique is realized to be capable of eliminating some of the major problems encountered in the ultrasonic testing of cracks, as it is practically free from the problem of crack closure as well as that of grain noises.
The accuracy as well as reliability of the developed measuring system has been verified through the evaluation of a number of 3-D back-wall cracks in 40mm-thick stainless steel plates.

Experimental procedures The ingots of Al7SiMg alloy (chemical composition: Si 6.69; Mg 0.37; Fe 0.29; Zn <0.01; Ti<0.01; balance Al; numbers as quoted by the producer in mass %) were melted in resistance furnace at 750 °C.
Mg3Sb2 will be crystallized at grain boundary prior to eutectic phases because of the high melting point.
As modifier for Al7SiMg alloy equal or over 0.20 wt. % Sb, some surplus Sb will precipitate at grain boundary in the form of compound Mg3Sb2.

In case of aggregates it depends on mineralogy and size of grain and can by specified by coefficient of thermal expansion or coefficient of thermal conductivity.
Even though the content of fine particles under 0.063 was 7.2%, the grains are very sharp and don’t contribute to improving the workability.
Volume 15/Number 1, March 1994

The size, the number and the distribution of these second phase particles have a great influence on the quality of aluminum foil.
A small amount of Mn can improve the corrosion resistance and weldability of the aluminum, Mg can improve its tensile strength, Ti and B are mainly added as grain refiner [6].
New combination of polishing and etching technique for revealing grain structure of an annealed aluminum (AA1235) alloy[J].

Microstructure of the WE43 (Mg-4Y-3RE) alloy in the as-cast state consists of solid solution grain Mg(α), yttrium (~0.7% at.) and neodymium (~0.3% at.) in magnesium, and eutectic Mg(α) + β (Mg12NdY) (Fig. 2b).
The number of repaired castings and welded structures is not satisfactory, which often makes production unprofitable.
The weld area has a significant grain fragmentation (Fig. 3c).

As we all known, diameter of particles can be calculated with Schrrer formula: Where D is the vertical direction of the grain size；λ is the wavelength of the x-diffraction ray；β is the diffraction peak width at half maximum；θ is the diffraction angle.
The introduction of Co, Ce can inhibit the TiO2 phase transition from anatase to rutile, and prevent the grains growth and agglomeration.
Oxygen adsorption is increased in the surface of composite particles, which can capture the photoinduced electrons to prevent the recombination with holes, and generate a large number of reactive radical species to promote the photo-oxidation degradation of organic matters.