Search results

As can be seen, casting strip is mainly composed of columnar grain and only a small amount of fine grain is found in the middle of casing strip.
The number of enabled slip systems increases under the conditions of warm rolling.
There is large stored energy in the grains.
Numerous small grains first appear at the grain boundary during annealing.
Table 2 The annealing process and the corresponding magnetic properties of 6.5 wt. % silicon steel sheets with a thickness of 0.30 mm Number Annealing process P1.0/400 [W/kg] B50 [T] Max.

Table 3 Equations used in the model to calculate austenite grain size and final ferrite grain size.
Equation and equation number Ref
Table 4 Predicted grain austenite grain sizes during roughing.
Ferrite grain sizes at room temperature: Measured and predicted values for ferrite grain size were as follows: measured grain at web, 10 ± 2 μm and 15 ± 2 μm at flange whereas predicted values were 10.2 μm and 15.3 μm, respectively for web and flange.
Table 5 Predicted austenite grain sizes during finishing.

Reduced grain size, increased microhardness, rougher and more fractal grain surfaces are observed for the alloy solidified by two-liquid casting in comparison of the microstructure obtained by conventional solidification techniques.
Furthermore, grain size is related with undercooling as 31 ~ Id and )/exp(~ 2 2 TkI ∆− where I is nucleation rate and 2k is nucleation constant[3].
Measured average grain number by ASTM method was 3.91.
Measured average grain number by ASTM method was 6.03.
Comparing Fig. 2(A) and 2(B) it is obviously that the microstructure in the Fig. 2(B) is much more fractal than that of shown in Fig. 2(A), extremely increased grain number proves the supercooling that achieved during two-liquid composite casting.

Through the analysis and research of cultivated land area change rate and grain yield rate and rate of urbanization.
Discusses the relations between and among population, cultivated land and grain production, Put forward some countermeasures and Suggestions.
Cultivated land, population and grain output correlation analysis Population, cultivated land and grain problem is the most specific population, ecology, economic relations is one of the most practical aspect, is the most basic in the relations between man and nature of a link, as the middle part of the relationship between the cultivated land grain production reality ability has a very important role.
Cultivated land is the material foundation to solve the problem of food and the food is the material base of existing of population, the number of people to a great extent, determines the relationship between the development and utilization of cultivated land condition, and influence the development of economy and society.
Based on the food security of China's grain demand forecasting and cultivated land resources allocation research [J].

A multicomponent single-phase model of a working face in Yanzhou mining administration is modeled[1,2],and the temperature field is simulated by SIMPLE algorithm.The bi-directional coupling between droplets and air is simulated by the stochastic model.After simulating the two cooling schemes using air conditioner and spray cooler[3,4],the distribution of temperature is analyzed. 1 The stochastic model 1.1 The action of grains in flow field Grains are forced by friction,because of the difference in velocity.The mathematical description is the Stokes resistance law[5,6]: 3 (Re ) D k k k F d u u f  (1) Where DF represents the viscosity resistance; kd is the diameter of grains;  is the coefficient of viscosity of air; u is the absolute velocity of air; ku is the absolute velocity of grains; (Re ) Re / 24 k D k fC , where DC is the drag coefficient, if Re 1000k , 0.687 24(1 0.15Re )
Magnus force is caused by velocity gradient which pushes grains migrated laterally,Bubinow and Keller calculated the Magnus force of a whirl ball: 31 [1 (Re )] 8 M k k k k k F d u O      (2) Where MF is the Magnus force; k is the density of grains; k is the angular velocity of rotation of grains; (Re )kO is the error related to the Reynolds number.
While flying in a flow field with velocity gradient,a lift effect forcing the grains(Saffman force): 0.5 3.0844 kS k k k F m u u u D      (3) Where SF is Saffman force; km is the mass of grains.
When grains falling freely,the gravity should be considered: 31 6 g k k F d g  (4) Where gF is the gravity of grains. 1.2 The stochastic model The grains are supposed to be spherical.And each group of grains is supposed to move in its own orbit from the initial position.The impact of grains is ignored[7,8]Then the equation of motion of grains could be expressed as follows: , , , , ' ' ' (1 ) ki i ki k k i k D i M i S i g i rk k du u u m m g m F F F F dt           (5) Where rk is the relaxation time, 4 / 3 ' ' rk k p D i ki d C u u     .
According to the interaction model between grains and eddies,the interaction time intt should be less than the lifetime e of the eddy ,and the distance intL should be shorter than the space scale eL of it. 0.75 int 1.225 / et C k   , 0.75 1.5 int /eL L C k   (6) During the lifetime of an eddy,the fluctuation velocity keeps fixed: 2 '' ii uu (7) Where  is a random number from -1 to 1,which follows the standard normal distribution. 2 The turbulent model of the main phase The airflow in working face is steady and non-equilibrium,which satisfies the continuity equation,the momentum equation,the energy equation and the composition equation.The state parameters of airflow could be expressed as a general variable: '   ,where  represents the time-average value,and ' represents the pulsation value.In order to close the

First part of description defines the machining method for surface (Bcbn-grinding, grain boron nitride, Bsg – grinding, grain SG, Ssk – turning, sintered carbide), specification next to dash behind pause defines the machining of notch (S-turning, B – grinding) The surface grounded by SG grain with grounded notch by CBN (cubic boron nitride) approves the longest durability in occurrence of ground surface with ground notch.
The surfaces formed with high quality show the longest durability from large number of measurements (Fig.11).
In case of manufacturing of design notch the ground notch made by CBN grains has the longest durability.
The influence of cuting speed does not become surprisingly evident with the CBN grains utilisation.
We can confirm here correctness of CBN grain application with grinding of design notches in production.

The same equation can be used for both the average grain studies and the individual grains study.
Peak locations θ were determined for all the five austenite grains' spots in the individual grain study and at a number of azimuths (fij values) in the average grain experiments.
Table 1: The Young's modulus in tensile direction for the 5 studied austenite grains Grain ID #1 #2 #3 #4 #5 Young's modulus 104 GPa 151 GPa 170 GPa 236 GPa 132 GPa 0 0.5 1 1.5 2 2.5 3 3.5 4 4.5 5 −0.5 0 0.5 1 1.5 2 2.5 3 x 10 −3 Applied strain [%] Elastic strain in tensile direction Grain 1 Grain 2 Grain 3 Grain 4 Grain 5 1 2 3 4 5 100 110 111 b) Figure 5: a) The residual strain evolution of five individual austenite grains. b) Inverse pole figure of these five austenite grains.
The Young's modulus for the most compliant grain (grain 1) was 104 GPa, and the stiffest grain (grain 4) had a Young's modulus of 236 GPa.
Plastic anisotropy is also a factor to consider and it involves the number of operational slip systems.

Fig. 2 Schematic explanation of the experimental and measurements set up for mirror-like finishing process Grain on the lapping head X Z Y Lens Lens Lapping head Vibration sensor Work piece Spindle rotation Slurry supply Lapping pressure FFT Vibration analyser Lapping tool Table. 1 Conditions of lapping for mirror-like surface finishing process Lapping slurry Water : PEO = 98:2 wt. % Diamond grain size #400~500 48.8[µm] #1200 15.8[µm] #2500 11.0[µm] Number of active grain on lapping head 30 230 850 Lapping speed 3000, 4000 [mm/min] (optimum) Lapping pressure 30 [MPa] , 40 [MPa], 45 [MPa] (optimum) Lapping time (Total) 15 [min] (optimum) Lapping head material Polypropylene (HV 11) Work piece material Brass (HV 91) , S45C (HV 170) , V10 (HV 2200) Type of lathe Linear motor lathe Influencing factors such as grain characteristics, lapping head hardness, lapping pressure, lapping speed, residual stress
Effect of active grain characteristics on lapping process.
The possibility of grain drop out is higher than other grain size of #400~500 and #1200 in this process.
However, there is limitation of lapping speed to maintain the number of active grain on the head to perform two body abrasive machining that has higher material removal rate than three body abrasive machining.
The number of active grains on the head influences on uniform improvement of surface roughness and geometrical form simultaneously.

In part B near depositing layer (is termed as the new β zone), the original β grains grow up as the columnar grains along build height direction.
But actually, growth height of the columnar grains want to be small comparing to that of as-deposited stainless steel,13 and the columnar grains are already unobvious when depositing to definite layer number, so its temperature gradient is less than that of as-deposited stainless steel.
This is because of more overlapping tracks, the number of the heat cycle that each depositing layer experience is much more too, thus causing the β columnar grains refine.
But for depositing the triangle entity, according to the characteristics of its depositing path, in one side of longer depositing path β columnar grains are bulky columnar grains, at anther side of shorter depositing path the β columnar grains is thin columnar grains.
The number of overlap track is more, the columnar grain is smaller. 4.

It is observed that hardness and densification increased significantly with increase in number of ECAP passes.
Although a number of studies have been carried out with ECAP of many wrought metals and alloys, only limited research on ECAP powder consolidation is reported [5, 6] and no studies have been reported so far on ECAP consolidation of nanocrystalline powders.
The microstructure of base alloy having large grains consisting of sub grain network in them, which is shown in Fig. 5(a).
It resulted in a microstructure with small fraction of coarse grains along with large amount of ultra fine grains (300-600 nm).
It is shown that MWNTs were uniformly distributed in the aluminum matrix along less grain growth.