Search results

In the nano-compounds further reduction of thermal conduction when compared to the coarse crystalline materials takes place, resulting from the increase of the number of grain boundaries [6].
The X-ray diffraction patterns for the coarse-grained and fine-grained CoSb3 compound obtained from the measurements and calculations are shown in Fig.1.
Data of the crystalline structure and crystallite sizes for the coarse-grained skutterudites.

The titanium suffers formation of hydrides, deformation of grain boundaries, change of metal porosity, occurrence of stresses and dynamic loads.
This is specifically relevant for hydrogen-implementing technologies for production of ultrafine grained nano and submicrocrystalline materials that have significant differences in comparison to coarse-crystalline materials.
Irradiation by beam with the energy density of 12 J/cm2 leads to formation of grained structure with the average dimensions of about 5 µm and folds that are oriented in different directions and embrace several grains.
VT1-0 titanium samples' surface profilogram after electron beam treatment with energy density of 12 J/cm2 [3] The dependence of titanium conductivity on integral hydrogen content in metal, according to [5] (X - relation of number of hydrogen atoms that correspond to one atom of titanium), can be expressed by the following regression equation (1).

Fig. 1 Structure of fluid dynamic pressure bearing Micro channel (Radial bearing) Micro channel (Thrust bearing) Sleeve Shaft (a)Conventional grooves (b)Proposal grooves Fig. 2 Three-dimension profiles of herring-bone grooves Fig. 3 Experimental setup of blasting Workpiece Nozzle Timing pulley Motor x-axis electric stage Compressor Regulator Abrasive grain Feeder Center z-axis stage y-axis stage Timing belt Tank z y x Table 1 Experimental conditions Abrasive grain GC #1000 Workpiece S45C (φ10×45) [mm] Blasting pressure P = 0.5 [MPa] Blasting stand-off distance y = 5 [mm] Inside diameter of nozzle d n = 2 [mm] Peripheral speed of workpiece V w = 18.8 [m/min] Mask Vinyl chloride (t 75 [µm]) The groove profile like this is employed for some thrust bearing [5].
Removal machining is performed with some set nozzle feed speed f in the direction of x-axis by blasting abrasive grains with compressed air.
Nozzle center Fig. 4 Image of division blasting area r(0) r(+2) r(+1) r(+3) r(+5) r(-1) r(-3) r(+4) r(+6) r(-2) r(-4) r(-5) r(-6) Abrasive grain Workpiece 0.25mm Machined surface profile Fig. 5 Relationship between stock removal and blasting time r(0) r(-1) r(-2) r(-3) r(-4) r(-5) r(-6) Stock removal S [µm] Blasting time t [s] r(+1) r(+2) r(+3) r(+4) r(+5) r(+6) r(0) Stock removal S [µm] Blasting time t [s] S45C GC #1000 P = 0.5MPa y = 5mm S45C GC #1000 P = 0.5MPa y = 5mm Table 2 Stock removals of each area r(0) r(0) r(-1) r(-2) r(-3) r(-4) r(-5) r(-6) r(+1) r(+2) r(+3) r(+4) r(+5) r(+6) Sr(0) Sr(-1) Sr(-2) Sr(-3) Sr(-4) Sr(-5) Sr(-6) Sr(0) Sr(+1) Sr(+2) Sr(+3) Sr(+4) Sr(+5) Sr(+6) When the nozzle feed speed
Four constant numbers an were calculated from Eq. 1.

It can clearly be seen that the grain size became finer as the cooling rate increased, this was because the under cooling degree increased and the phase transition temperature lowered as the cooling rate increased, the number of nucleation increased resulted to the grain was very fine.
The ferrite grain nucleated and grew in the grain boundary of cooling austenite at first, all of the remaining austenite transformed to pearlite as the temperature decreased to the eutectoid transformation temperature.

The diffraction lines could be indexed with respect to tetragonal structure and matched with JCPDS file number 06-0452.
Table1 % perovskite phase, c/a ratio, average particle size, and average grain size of PT Excess PbO level (wt.%) Calcined powder Sintered ceramic % perovskite phase c/a ratio Average particle size(µm) c/a ratio Average grain size (µm) 0 100.0 1.0623 0.7 1.0621 32.63 1 100.0 1.0619 2.4 1.0614 4.58 3 98.8 1.0614 2.7 1.0608 7.68 5 93.4 1.0610 4.0 1.0601 11.33 Fig.3 Shows SEM micrographs of calcined powders.
The SEM micrographs of sintered ceramics are shown in Fig.4 and the average grain size is shown in Table 1.
The average grain size decreases with increasing amounts of PbO until 1 wt.%, then slightly increases with further excess PbO.

In addition, the creep rate depends on the grain size and distribution [10].
It could be observed α grains (HCP) and dark regions that define the presence of β phase (BCC) along the grain boundaries of the alloy.
Bimodal structure has similar microstructure and grain size compared to equiaxed structure, however the heat treatment given higher mechanical resistance due to the presence of martensitc phase in the darker region of the picture.
Using standard regression techniques, the results can be described in terms of power-law creep equation (eq 1): = B sn (1) where n is the creep stress exponent and B is the structure-dependent constant and these parameters are usually determined from a number of constant load creep tests.

The XRD patterns of the sample sintered by SPS method exhibits intense diffraction from (00l) planes with little diffraction from other crystal planes, indicating that the grain is preferentially oriented.
As shown in the photograph, the shape of the crystal grain of 1~2µm is flaky, as the oxides have layered crystal structure of Ca2Co2O5 [9, 10].
As seen from the Figure 2(a), a large number of pores exist in the sample, which greatly reduces the bulk density and impairs the electrical transport properties of the samples.
The SPS sample shown in Figure 2(b) is composed of well-oriented sheet-like grains, which may be helpful to improve the thermoelectric properties.
These results indicate that SPS method can greatly improve the thermoelectric properties with grain orientation and high bulk density.

The grain composition of the investigated prepared crushed samples of the opaka-like rocks is presented in Table 1.
Grain composition of selected samples Content of fractions, mm, in% 2.5-1.25 1.25-0.63 0.63-0.315 0.315-0.16 less than 0.16 10.8-13.2 16.4-18.6 18.1-20.7 13.1-15.9 35.7-37.5 Dependences of the effect of pressing pressure on the density of compacts for dampening press powders based on a low-clay "normal" non-carbonate opoka, clay and carbonate opoka are shown in Figures 1-3.
This happens because primary grains of the original powder are destroyed.
They arise for many reasons, including due to the presence in the opokas of micaceous minerals, which are somehow released when the primary grains are destroyed. 4.
Dependence of the resistance limit in compression of burn samples on the pressing pressure for powders of different moisture based on carbonate opoka (Т burn. 1060 ° C) Conclusions and Further Prospects for the Topic Development Proceeding from the foregoing, it can be said that the pressing process of pressure powders based on opoka-like rocks has a number of features compared with clay raw materials.

Experimental The commercial ZrB2 powder with purity 99.5% and grain size 12.68µm was used as the starting powder.
Due to intenerate of ZrO2 whose melting point is lower than that of ZrB2, it fills in the interspaced between ZrB2 grains.
It shows that there were a large number of pores in the pure ZrB2 sample, and its densification was only 87.5% (Fig.5); under the same condition, the ZrB2 @ ZrO2 composite powder was sintered with more than 95% density, and there was nearly no pore in the sample.
It shows that the ZrB2 grain boundary was connected by the other phase.
The ZrB2 grain boundary was connected by T-ZrO2 phase.

The blacklands in northeast China is an important food producing area and marketable grain base, it plays an important part in the development of national food security.
Blacklands in northeast as an important commodity grain base in our country through the shorter development course, more for 100 years or so, some areas only 50 years [2].
The gullies in the influence of landscape features at the same time, has brought the serious loss of grain.
Soil and water loss carry a large number of silt downstream reservoir sedimentation, river bed up, some small river rivers bottom is higher than the original ground to form the ground.
Soil and water conservation monitoring from water and soil resources and maintain a good ecological environment, the use of ground monitoring, remote sensing, global positioning system (GPS), geographic information system, a variety of information acquisition and processing methods, for the cause of soil and water loss, number, strength, scope, harm and control effect of the dynamic monitoring and evaluation, is the foundation of soil erosion prevention supervision and management work.