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For example, the thermal conductivity k of wood across the grain is different than that parallel to the grain.
Biot number Bi= hd /k.

Alloy specimen TEM diagram From figure 1 can see, alloy specimen, there are a lot of black precipitated phase distribute dispersedly; The figure 2 can see, in the alloy sample grain internal distribute dispersedly with uniform size small precipitated phase, precipitated phase diameter is about 10 nm.
Heat treatment process Sample number Solution temperature[℃] Solution time[h] Aging temperature[℃] Aging time[h] note 0 — — — — as-cast 4 750 2 400 4 Heat treatment 5 750 2 500 4 Nano enhanced copper alloy specimen processing into standard GB6397-86 tensile test piece , as-cast sample label is 0-1 and 0-2,after 400℃ ageing process samples label are 4-1 and 4-2,after 500℃ ageing process sample bar were label for 5-1 and 5-2.Test on CMT4105 universal mechanics testing machine,test process according to GB/T228-2002 "metal material room temperature tensile test method", tensile speed is 2mm/min.Through the review of the literature that conventional tin bronze tensile mechanical properties[2],and nanometer enhance copper alloy main tensile properties such as shown in table 3.
Conclusion (1)This topic using centrifugal investment casting to prepare nanometer enhance copper alloy castings, there are a lot of black precipitated phase distribute dispersedly in the alloy , and there are a lot of nanometer level of precipitated phase distribute dispersedly in the grain, precipitated phase of the average diameter is about 10 nm; (2)Nano enhanced copper alloy specimen tensile strength, yield strength, elongation and other major tensile tensile properties have a greatly raised than conventional casting bronze , which after 750 ℃ solution 500 ℃ ageing process sample have mechanics optimal performance.

Attached cell number was determined by trypsinization and hemacytometer counting.
Results and Discussion There were significant differences among the four groups in grain size, surface microstructure, as assessed by XRD and SEM (Fig. 1, 2).
Figure 2(b) illustrated the uniform structure of the nHA and the range of grain size was approximately 70~90 nm.

When the nano-particle/polymer matrix composites are subjected to external shocks, the small size of nano-particles leads to more silver patterns that can absorb large amounts of impact energy (higher surface activity of nano-particles, with the force between the matrix resin), and more importantly, prevent the silver nano-particles with a grain cracking function (the mechanism is shown in Figure 4).
The silver grain is produced on the particle surface, and the absorbed impact energy is mainly use to pull off the silver pattern and fill the polymer-based micro-fiber.
With the addition of nano-SiO2, the impact fracture increased significantly at the torn edge, and a number of degumming particles can be ovserved.

Introduction Metal-nanoparticals ,their oxidation resistance is poor because of the surface effect.The object of studying nanomaterials＇passivation is to decrease the surface activity so that it can stay in the air longer, to obtain the ideal nanomaterials.It has been a number of ways on the reaserch of surface passivation of nano-materials,such as formed self-assembled protection layer or put organic film on the surface .However, pollution the surface of nanoparticles is the disadvantage , brought impurities in the application.
(a) no oxidized Zn nanoparticles (b) the oxidation of Zn nanoparticles Fig.1 Wide angle X-ray diffraction spectrogram of Zn nanop ticles X-ray profile analysis.In this paper,we measure the crystal grain size of Zn nanoparticles by small angle XRD and XRD,and calculate the particle radius by the Jinie ear.
Fig.5 The curve of the changs of O in the nanoparticles Fe with time Conclusions (1)Study of metal nano-particles effective grain size is about 100 nm, particles with a complete form

Introduction Lanthanum gallate with partial substitutions of strontium and magnesium (LSGM) is a promise solid electrolyte for application in solid oxide fuel cells operating at intermediate temperatures (IT-SOFC), because of the combination of its properties like high ionic conductivity and ion transport number, chemical stability in a wide range of oxygen partial pressures and good mechanical strength [1-3].
Subsequent calcinations resulted in continuous growing of the particles/grains.
The particle/grain growth process occurs very fast at this temperature, and then it was decided to intercalate a step of attrition milling between two successive calcinations.

Introduction FSP is a new material process technology，which developed by friction stir welding. [1] FSP has been used in researches of composite metal materials as the specific heat- mechanical characteristics.[2] The principle of FSP is making mixing needle of high-speed rotating squeezed into workpiece,and make the workpiece heating,softening,plastic deformation and recrystallization by friction between surface of workpiece and welding tool to form a dense fine grain structure and improve mechanical properties. [3-4] In this paper, coating of high-speed steel powder prepared by flame spraying were enhanced by FSP .The processing of FSP make the coating forming homogeneous recrystallization organization,reducing the porosity of the coating, and improving the density strength and bond strength.
Compare with unmixing zone in the coating，the grain of high-speed steel coating distributed more uniform.The hardness of coating surface have been improved.
In the SEM image of Single-time FSP, coating of high-speed steel and the substrate were not fully integrated with each other.A new strengthening phase which pervaded a large number of uniform distribution particle was produced after multi-times FSP.

Spindler et al. [2] represented that Al can form a dense aluminum films on the surface at high temperatures, and the dense aluminum films can prevent oxygen in the air into the matrix, however, steel-casting is easy to be broken, when the content of Al is very high due to the brittle Al2O3 and AlN phase on the grain boundary.
A number of researchers [4-5] used casting infiltration technology to form different alloy composite layer on casting surface, however, rare studies were selected 75 ferrosilicon (refered as 75 Si-Fe) aluminum powder as cast-penetrated agent, thus, in present paper, the microstructure characterization and micro hardness properties of the heat resistant steel grate surface were investigated.
In the infiltration experiments, the average grain sizes of 75 Si-Fe was 75um to 150um.The silver paint consisted of resin, pigments, solvents, aluminum powders and some aids.

In the absence of a magnetic field at kA>0 equilibrium position of the magnetic moment of a grain coincide with the position of the effective axis: ϑ=π2, φ=γ and ϑ=π2, φ=π+γ.
Maximum critical field of irreversible change of the magnetic moment of a grain can be determined minimizing the formulas (5) and (11) In the first case (ku ‖ H) it equals to: H0=IskN2+2kNK1cos2α-ψ0+K12 (12) regardless of kA, while in the second case (ku ⊥ H): H0=IskN2+2kNkA+kucos2α+kA+ku2
Reference number is Government Order-2013/287, code 2.8649.2013.

The grain size of GSAG:Ce Fig.1 XRD patterns of GSAG:Ce powder calcined at different temperatures phosphor is in the range of 20-30 nm, as can be estimated from Fig.2.
The powders prepared using only urea as fuel showed large particle size and severe agglomeration between adjacent grains in our experiment.
Acknowledgements This work is supported by Shanghai Leading Academic Discipline Project, Project Number: P1502; and Science and Technology Foundation of Shanghai Higher Education, No. 040B07.