Search results

Average grain size of as-milled diamond powders estimated using Scherrer’s equation, were 29 nm and 25 nm after 30 h and 40 h, respectively.
Increasing milling time from 30 h to 40 h seems not to decrease grain size of diamond powder, however, leads to the uniform in both rounded shape.
Lattice strain and grain size of milled diamond powder as a function of milling time.
ND particles with relatively uniform in shape and average grain size of 15 nm were obtained when micron diamond powder was milled for 40 h.
Acknowledgement This work was financially supported by the main research projects of the National Science Council of the Republic of China under grant numbers NSC 100-2221-E-027-047.

The results showed that the characteristic diffraction peaks of MgO structure were all presented in the XRD spectrum of MgO (where the 2θ were 36.7°, 42.8°, 62.2°and so on), which was consistent with the MgO standard card（Card Number:04-0829).
The average grain sizes, calculated by Scherrer D=0.89λ/(βcosθ) with different grinding time were 9.54 nm, 9.72 nm and 9.47 nm, respectively.
The extension of grinding time benefited the fabrication of nanometer-MgO powder with small grain size and little agglomeration.
It was indicated from the experimental results above that the antibacterial performance of magnesium oxide nanometer powder was related to the grain size and the particle's surface defects.
The smaller the grain size of nanometer-MgO was, the stronger adhesion was, as discussed in 2.4.

The outer layer is mostly composed of beta-NiAl phase, whereas the inner contains a large number of precipitates.
SEM surface observation reveals the presence of ridges localized at the vicinity of bond coat grain boundaries.
Bond coat grain boundaries are still visible by the ridges appearing clearly in Fig.2.
However, for the initial compression steps, only oxide located at ridges spalls off, whereas oxide located above bond coat grains remains adherent.
Spalled area observations reveals oxide grain imprints in the bond coat, while no interfacial voids are visible.

At high frequencies the series resistance increases due to a skin effect around cathode grains that can be represented by A1ω 1/2 + A2ω 2, where A1 e A2 are experimental constants.
Although some MnO2 patterns, namely those from γ-MnO2, have a rather poor quality, exhibiting only a small number of sharp and broad lines on a diffuse background [Error!
The MnO2 counter-electrode was in general well crystallized, with grain sizes typically between 100 and 200 nm.
A columnar grain morphology could be observed within 200 nm from the dielectric.
Patterns of highly faulted grains induced streaks in reciprocal space along the rows parallel to 020, indicating the Figure 6 Electron microdiffraction pattern of a strongly diffracting MnO2 grain.

In order to overcome the disadvantageous property, a number of researchers have studied improvement of machinability of AlN ceramics by adding hexagonal BN (h-BN) as a second phase [7].
Recently, nanocomposites in which nano-sized particles were dispersed within the matrix grain/or at the grain boundaries were studied [8-12].
The starting powders for the composites were a commercially available AlN powder having an average grain size of 1.3 µm (F grade, Tokuyama Corp., Yamaguchi, Japan).
Nano-sized BN particles were homogeneously dispersed within AlN grains as well as at grain boundaries.
TEM observations of the nanocomposite revealed that the nano-sized h-BN particles were homogeneously dispersed within AlN grains and also at grain boundaries.

With the rapid development of China water conservancy and hydropower construction, the annual number of earth and rockfill dam is increasing, and the height is also rising, reaching more than 300 meters (m)[1].
Triaxial tests of geotechnical grille reinforced sand-gravel Test sand-gravel, Geotechnical grille and Equipment The sand-gravel used in the study was from a clay core rockfill dam in the west of China, the maximum grain size is 40 mm, the average grain size is 14 mm.
In the "band", grains interact with each other relatively strong, so the specimen is relative stable and not prone to slip and dislocation.
When the specimen is under shear stress, the grains near the geotechnical grille which also means in the "band" is hard to occur failure.
In this study, dislocation began from the grains which were between two pieces of the geotechnical grille, so it forms "candied fruit string" type of failure mode as shown in the picture.

In all cases weld microstructures typical of Ti-6Al-4V alloys were observed with significant grain growth in the fusion and heat affected zones.
With respect to arc based process, the arc stability of the GTAW process may also be used as a measure of weldability, with poor arc stability known to cause a number of common weld defects [8].
Post weld analysis of weld zone microstructures revealed typical solidification type structures with large equiaxed grains in excess of 1mm in the fusion zone (FZ) and ranging from 100μm to 500μm in the heat affected zone (HAZ).
The large grains are understood to originate from the prior β grain structure developed upon solidification and are shown to be composed of the so-called ‘basket weave’ morphology with colonies of α-Ti laths surrounded by retained β-Ti.
While the post-weld microstructures of RHP samples closely matched those of wrought samples, it is clear that press-and-sinter samples differ significantly in grain growth of the HAZ and remain less distinct due to the high porosity levels in the base material.

The large-size η phase near the interface between YG30 and weld bead was due to the coarsening of tiny η grains in the liquid weld bead.
In comparison with the diffusion welding, TIG arc welding offers a number of advantages, such as welding at any location, easily realizing the automation, etc [3].
Grain boundaries in the η phases and the remaining WC particles (white) were clearly observable (Fig.3a).
Meanwhile, WC grains can maintain the original morphology, because it dissolved slightly, as shown in Fig.3(c).
Along with the nucleation and growth of the η phase the amalgamation of the η phase grains happens in the liquid weld bead.

The grain sizes in the coatings are around 4 nm.
Comparing with TDM, SGM is much easier to control the grain size and the composition.
It seems that the nano-grains have not grown up to their normal dimension.
The voltametric charge measurement can determine the number of active sites, which is proportional to the area of the curves.
The diameters of grains in the coating annealed at 450� are about 4 nm.

For circular diamond saw blade: h=H/Z. (4) Where H-the depth cut by per revolution of the circular diamond saw blade; Z-numbers of segment in a circular diamond saw blade.
To take the circular diamond saw blade of � 1600 and its segment dimensions 24 mm×12 mm× 9.4 mm as example, when sawing granites, its feed depth is 10̚12mm in general, the thickness of pure alloy layer is calculated from the Eqs.3 and 4 d=2h·tgž=2(H/Z) tgž=2×(12/108) tg(60°-70°)=0.38-0.605(mm) h is also determined by the permitted depth cut by diamond grain.
If diameter of diamond grain is d0, h is less than 3d0/8.
Key Engineering Materials Vols. 101 Table 1 Productive test data from sawing granites by layered segment A B C D E F G H I J 25 7 0.8 40 388.80 0.68 1.50 264.38 K 22 7 0.7 40 404.35 0.75 1.60 303.26 L 19 7 0.6 40 419.90 0.80 1.70 335.92 M 16 7 0.5 40 435.50 0.81 1.80 352.76 N 13 7 0.4 40 451.00 0.80 1.70 360.80 O 603# 0 1 0 40 518.40 0.66 1.50 342.00 P 0 1 0 40 518.40 0.37 1.00 192.00 Q 13 7 0.4 40 451.00 0.44 1.20 198.44 R 16 7 0.5 40 435.50 0.47 1.20 204.69 S 19 7 0.6 40 435.50 0.47 1.20 197.35 T 22 7 0.7 40 404.35 0.45 1.10 182.00 U 635# 25 7 0.8 40 388.80 0.40 1.05 155.50 V Notes: A-Rock symbol; B-The ratio of pure alloy layer; C-Layer number of segment; D-Thickness of pure alloy layer; E-Diamond concentration; F-Diamond consumption; G-Sawing efficiency; H-Service life of saw blade; I-The ratio of diamond consumption; J-Sawing feature; K-the circular diamond saw blade vibrates, rock ridges form; L-the circular diamond
If the thickness of segment is T, the number of layer is N and the number of pure alloy layer is n, then T×16%/0.5=n N=2nˇ1 (n is taken as positive integer ).