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. *** (2004) pp.573-576 online at http://scientific.net Ó 2004 Trans Tech Publications, Switzerland Fine-grained Access Control of PDM and CAPP S.H.
The function of fine-grained access control system was presented.
Based on RBAC, it is feasible to realize the fine-grained access control for the integrated PDM and CAPP system on the Web application layer.
To keep data resources from being damaged, attacked and stolen, a fine-grained access control model for PDM and CAPP was set up.
R&D Program for CIMS of China under Grant number 2001AA412120.

Meanwhile, some small grains maybe deform by grain rotations.
This indicates there is a great number of grains with high angle boundaries.
The rings as marked by number one to six correspond to (102) and (110) planes of Cu4Y, (111), (200), (220), (220) and (311) planes of α-Cu.
Therefore, a considerable number of extinction fringes exist in most small grains.
Otherwise, the small grains maybe deform by grain rotations.

The main effect that is expected is their influence on the increase in the number of nucleation sites [2-4].
An increased number of inoculants means a larger number of grains, that is, a finer microstructure in the weld metal.
Therefore, the coarse grain ferrite types such as Widmanstaetten, intragranular idiomorphic and grain boundary allotriomorphic ferrite can be partially replaced with finer grained acicular ferrite [7].
As the number of non-metallic inclusions is higher, a finer grained ferrite microstructure can be obtained, resulting in improved mechanical properties of weld metals.
· The increase in mechanical properties of welds is the result of an increased number of non-metallic inclusions

Because the number of strengthening phase particle Al3Zr increases greatly near fusion line after PWHT, the ratio of heterogeneous nucleation further increases, consequently, it promotes the formation of fine equiaxed grain.
The microstructure of weld metal has been changed from equiaxed dendrites to equiaxed grains after PWHT, the number of eutectic structure greatly decreases.
Because the weldment consists mainly of eutectic structure in AW condition, and the number of strengthening phase precipitating within grain is small, moreover, the precipitate free zone (PFZ) with relatively low strength does not generate at grain boundary, consequently, under the action of tensile stress, plastic deformation proceeds dominantly within grain.
It proves that the weldment mainly consists of equilibrium phase δ in AW condition, and the number of strengthening phase is lower.
Through analysis, the rod-like phase should be T(Al2MgLi) phase, and the number of δ′ phase is very small around the T phase.

In CNM process, the main principle is to maximize grain density in the melt and promote grain growth in a non- or less-dendritic motion.
On the other hand, in pouring method II (pouring outside the gauze), a huge number of wall crystals will be created by crystal fracture and crystal remelting.
Therefore, the grain size within the gauze is decreased dramatically.
Below 300°C, a fine equiaxed grain structure is obtained and the grain size increases slowly with the mould preheat temperature.
Pouring outside the gauze leads to a large number of "wall crystals" being brougt into bulk melt, forming very fine equiaxed microstructure.

Metals that undergo DDRX exhibit a number of characteristics that are well established by experiment [1,2].
The driving force for both nucleation of new grains and grain growth is the stored energy.
(1) dei is the strain increment experienced by grain i, σi is the flow stress of grain i.
The number of subgrains able to nucleate from each grain (Nnuc,i) is given by the product of the fraction of subgrains able to nucleate (Fsub,i) and the number of subgrains lying on the grain boundary (Nsub,i) (Eq. 4): (4) For model implementation, each new grain nucleates from a randomly selected grain and has an initial size equal to that of its instantaneous critical radius rc,i.
The initial grain size distribution consists of grains that are normally distributed with a standard deviation of Do/3.

With the improvement of laboratory equipment and development of computer technology, a large number of experiments and numerical simulations have been made since 1970s..
Zhang Gang of Tongji University for the first time established the numerical model based on the grain size curve to simulate the pipe process [3].
We can obtain the porosity in two-dimensional after the three-dimensional model is built according to the grain size curve and porosity in the software CAD. 2.1 porosity change and particle number calculate The porosity transitional equation between two-dimensional and three-dimensional space is got by Hoomans(1996), and Dr.
Fig.2 Grain sizes diagram of different gravel Tab.1 Number of particle under different diameters Cu 10~7number of particles 7~5 number of particles 5~2 number of particles 2~1 number of particles 1~0.1 number of particles 2.5 66 133 2650 849 12627 14.5 0 0 2241 2228 50509 30.5 264 159 565 1910 38671 * This is the ideal value, in order to reduce the computing time, according to the recommendations of literature [5] value and the present calculation conditions, the model was further simplified. 2.2 Mechanical model and Micro Calibration The soft-sphere model, which was proposed by Cundal and Strack in 1979 was adopted in Granule in the Numerical model.
When convergence had happened, both force chain map and flow chart show that grain structure of the sample was stable.

Introduction It is known that magnesium alloys are of great interest for medical applications since they possess a number of advantages in comparison with other materials [1-3].
The mean grain size is 42±7 µm, and the coarse grains with a size of about 200 µm are observed.
Study by TEM showed that HPT processing leads to strong grain refinement, the mean grain size is 210±15 nm (fig. 3a).
According to SEM images, the mean grain size is 1.4 µm.
The low ductility can be explained by the accumulation of a large density of lattice dislocations in the conditions of a limited number of slip planes.

On Equilibrium and Stationary Coefficients of Grain Boundary Segregation B.S.
Grain boundary (GB) segregation is usually characterized by two different coefficients: either b, which is used in the isotherm of equilibrium adsorption (Langmuir, McLean etc.) or s, which can be determined as a ratio of grain boundary and bulk concentration in the immediate vicinity of grain boundary.
Grain Boundary Diffusion and Grain Boundary Segregation (Scitec Publ., Switzerland 1998)
McLean: Grain Boundaries in Metals (Clarendon press, England 1957)
Gust: Fundamentals of Grain and Interface Boundary Diffusion (Wiley, Chichester, N.

Desired film thickness was achieved via control of the number of deposition sequences.
Since the physical properties of these states are often sensitive to even a small change in intrinsic and external conditions, there appears to be a number of colossal effects.
AFM result suggests that all the films have fine grains and the grain size gradually increases with increasing the thickness.
The distinct grain structure can be observed for the films of various thicknesses which shows small cluster like growth of grains. the number of grains has been reduced and larger grain sizes could be observed as well grain boundary depart with lift of thickness.
This reduction in resistivity is caused by decreasing the number of grain boundaries as the thickness increases.