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The theory of surface parts engineering is developing in a number of directions; according to the works [5–7], there are about 30 of them (27 items).
As a result of laser action, structural-phase transformations occur in the surface layer, a fine-grained hardening structure is formed.
At that, the number of drilled holes was evaluated before critical wear or breakage of the drill bit occurred.
Figure 2 shows the real details of the switching equipment, in particular, the shear surfaces along the hole of the relay armature RES-48 formed by a drill bit in the initial state and by the modified one, drilled with the same number of holes.
This mode of laser exposure should be considered the most acceptable for practical use, and the decrease of the Rsm index characterizes the mutual influence of the roughness parameters on the grain size or dispersion level.

Because on the one hand,under 1350˚C, andalusite dynamically is relatively so stable that its mole number basically remains unchanged, on the other hand, both the secondary mullitization reaction (2) and the dissolution of surplus quartz are the reduced process of molecular number, thereby the systematical total mole number decrease and mol percentages of andalusite relatively increase.
When the specimen was sintered under 1450˚C, the shapes of the most of mullite grains are short fibers which crisscross each other and only a few presents other irregular shapes.
(a) SEM under 1350˚C (b) SEM under 1450˚C (c) SEM under 1550˚C Fig. 3 SEM of the specimens at different sintering temperature While kept warm at 1550˚C, mullite grains present lath shape and are bound together.
Because under 1550˚C the mullite formed at 1450˚C recrystallizes and atoms of silicon and oxygen supersaturates, while naturally cooling, and then the grains of mullite change into lath and supersaturated atoms of silicon and oxygen deposit in the form of quartz, and quartz serve as binder.
Conclusion According to the studies, it can well be drawn that in the range of experimental temperature, mol percentage of mullite synthesized by andalusite mineral materials of Mei County China first increases and then decreases with the rise of temperature, and while sintered at 1450˚C and then kept warm for 3 hours and cooled to room temperature naturally, andalusite mineral materials fully transform into mullite and the majority of grains of mullite transformed at 1450˚C present in the form of short fibers, and the crystallinity of short mullite fibers is the best, and their structure defect the least and their performance the most stable and their length-diameter ratio the largest.

The technology of ablation casting is mainly predestined for manufacturing castings, with varying wall thickness and complicated geometry, in sand moulds, in which castings solidify relatively slowly, which results in an unfavourable grain growth.
In order to improve mechanical properties by obtaining a fine-grain structure, ablation cooling of the casting mould is applied directly after pouring in liquid metal.
The patent for the equipment for the destruction of the sand mould and controlled, directional cooling of the casting was filed to the Patent Office of the Republic of Poland and was assigned the number P.404518.
The results of SDAS measurements conducted on samples cut out from sand castings Measurement number SDAS in μm for varying wall thickness 3 mm 6 mm 9 mm 12 mm 15 mm 1 25 27 23 34 37 2 20 24 30 34 38 3 18 20 28 39 45 SDAS mean 21.0 23.7 27.0 35.7 40.0 Table 2.
The part of the casting that solidifies the fastest (the lowest thickness of the wall) shows a fine microstructure that increased in the coarseness of grains with an increase in the wall thickness (lower cooling rate).

Selection of abrasive type, grain and concentration need consider many factors such as ground material, ground roughness, grinding speed, feed speed, grinding depth, and manufacturing cost.
Ltd. was finally selected, and 120/140 grain size and 160 concentration were determined.
The vitrified bond material was selected by taking abrasive type, grain size, grinding requirement and production process into account.
Generally, the abrasive, grain size, bond, structure number and grinding speed should be determined according to the ground workpiece material and the grinding precision demands.
Table 1 Grinding experimental parameters Table 2 Statistical productive grinding results Parameters Wheels cycle (sec) Dressing interval （ i Wheel life [piece number] Roundness [µm] Cylindricity [µm] Roughness [µm] Wheel imported ≤32 130 25,000 3 3 Rz4 Wheel developed ≤30 150 32,000 ＜3 ＜3 Rz4 Table 3 Changing rules of ground workpiece quality after dressing Number of Workpiece Rz[µm] Roundness [m] Cylindricity [µm] 1 1.7 1.5 2.0 50 2.0 1.8 1.8 100 3.0 1.9 2.0 150 3.2 2.2 1.9 Grinding Experiments Experimental Conditions.

Xuwei port Fig. 1 Location of sediment sampling point Table 1 Sediment particle size Sampling location classification Particle concentration（%） Grain size parameter sand silt clay D50（mm） Qdφ Skφ -3m clayer silt YT 8.9 51.7 39.4 0.0078 1.78 -0.30 -5m clayer silt YT 10.2 55.4 34.4 0.0106 1.83 -0.05 Test equipment and method Test carried out in the wave-current flume, which length 68.0m, wide 0.7m and height 1.0m, the front layout the irregular wave machine and its control system, the middle has a silt storage length 3.0m and height 0.1m, the back set a box for absorbing wave energy.
Test result and analysis Incipient condition can described as the incipient velocity, friction velocity, critical shear stress, critical shields parameter and sand Reynolds number, while the critical shear stress, critical shields parameter and sand Reynolds number can be calculated by Eq.1~Eq.3
（1） （2） （3） Where is the density of water; is the density of silt; is the friction coefficient of wave-current; is the bottom flow velocity under wave-current action; is acceleration of gravity; is the median grain size of silt; is the bottom friction velocity under wave-current action; is kinematic viscosity coefficient.
(2) when the wet density for 1.4t/m3, the critical shear stress is between 0.24 N/m2~0.29N/m2 of the sediment from -3m water depth, and about 0.21N/m2 of the sediment from -5m water depth; when the wet density for 1.5t/m3, the critical shear stress is between 0.35 N/m2~0.46N/m2 of the sediment from -3m water depth, and between 0.37 N/m2~0.44N/m2 of the sediment from -5m water depth; the incipient condition will slightly decrease with the median grain size of sediment increasing.
Conclusion This paper combination the experimental methods and theoretical analysis method, studied the incipient condition of two sampling sediment from -3m and -5m water depth in main channel of Xuwei port, Lianyungang under wave-current action, the results show that the sediment incipient condition will increase with the wet density increasing, and decrease with the median grain size increasing.

The presence of grain boundaries in ceramic gives rise to additional effects which are not present in single crystals and which have important practical implication.
In present paper, we solve the problem of scattering of electromagnetic waves by grain boundaries and domain structure in PLZT ceramics using T-matrix method.
It is well known that, light scattering has found increasing use in studying the crystal structure heterogeneities, including the domain structure and phase transitions and grain boundaries in imperfect ferroelectrics.
In our case the cylinder is grain boundaries (or domain), so the imaginary part of its refractive index equal to 0.05, 0.15, 1.20, 1.30, 0.40.
Sum expressions containing the expansion coefficients over a finite number of terms to obtain quantities of interest like the electric field, intensity or cross section.

When cooling rate is 1 ~ 2°C/s, the microstructure is mainly based on granular bainite (Fig. 3d, Fig. 4b); as cooling rate rises further, the number of granular bainite declines gradually yet lath bainite (LB) appears.
It suggests that when welding with little heat input, the coarse grain region of X90 pipeline HAZ has a moderate hardening trend.
When cooling rate is higher (t8/5≤15s), the coarse grain region of X90 pipeline HAZ has a moderate hardening trend. 2.
When t8/5 is between 15s and 150s, the microstructure of X90 pipeline steel weld HAZ is finely grain and moderate hardness.
To avoid forming a large number of martensite due to rapid cooling, and to reduce welding joint cold cracking sensitivity, the weld preheating temperature is controlled about 100°C.

The CFU number was calculated to determine the number of colonies per coupon each incubation time.
After the homogenization, the microstructure of all as homogenized alloy samples showed polycrystalline grain structure and segregation was less significant compared to the as cast samples.
The as-cast microstructure is dendritic and the as-homogenized is polycrystalline grain.
The number of CFU or viable bacteria colonies as shown in Fig. 5 is the number of bacteria colonies that are reduced from its initial condition.
Homogenization treatment changes the microstructure of the alloys from dendritic to polycrystalline grain structure.

SEM photographs revealed that as Te-content increases the compactness of the surface and the connectivity of the grains decreases, while pores and voids increase as a result of decreasing the amount of Bi and presence of multiple-phases in the sample. 1.
At low Te-concentration, we can see that the compactness of the surface and connectivity of the grains is the higher; this observation can be attributed to the lattice diffusion promoted by the higher content of Bi.
Of course at higher values of x, the Bi content decreases; so surface compactness and connectivity of the grains.
The number of pores and voids considerably increases due to Bi evaporation and the multiple-phases present in the sample.
Presence of multiple-phases leads to decrease the grain size, sharpen the edges of the grain and increase the width of the grain size distribution.

The substitution of Cu for Ni, instead of changing the major phase Mg2Ni, leads to a visible refinement of the grains of the as-cast alloys.
The substitution of Cu for Ni, instead of changing the morphology of the alloys, causes a significant refinement of the grains.
The enhanced hydrogenation property by melt spinning is undoubtedly associated with the refinement of the grains produced by the melt spinning [9].
Consequently, high densities of crystal defects such as dislocations, stacking faults and grain boundaries are introduced.
The large number of interfaces and grain boundaries available in the nanocrystalline materials provide easy pathways for hydrogen diffusion and accelerates the hydrogen absorbing/desorbing process.