Search results

Consequently, during etching of SiC single crystals at optimum conditions only the strained areas due to defects such as dislocations, micropipes, low and large angle grain boundaries, twin boundaries etc. are preferentially etched to produce etch pits or profiles with definite configurations.
Acknowledgements Financial support was provided by the German Science Foundation (DFG, contract number WE2107) and the Bavarian Research Association (BFS).

The improvement in hydrogen permeability after annealing is attributable to the number of the percolation paths which could be highly sensitive to the intergranular separation between the neighbouring Nb grains.

On the other hand, polypropylene woven fabrics also has disadvantages, such as low water permeability in horizontal direction, low porosity and pore shape changing easily, thus is difficult for obstructing fine soil grains passing.
Thus numbers of expanded molecular chains in PP filament are lower than those of in the PP ribbon-like filament, which makes molecular chain shrink more severely in the former and led to its bigger shrinkage.

The analysis of this research consists of three parts: firstly, it analyzes the integrity of ceramic materials in the process of RUM and the correlations between RUM and machining conditions through the results of axial sub-sectional measure in means and standard deviations of statistics; secondly, it discusses the machining parameters such as drill diameter, rotation speed of main shaft, power and feed rate which are the keys in the research in the condition that grain size is fixed; finally, it discusses the influences of Taguchi quality experimental design method on machining quality with the expectation achieving better and bigger MRR of holes wall to ensure the effectiveness after drilling and improve the machining efficiency.
Conclusions The following conclusions may be drawn based on experimental results above: 1.Relational equation of drilling holes wall on MRR and drilling parameters and tool geometry may be used to forecast holes wall quality. 2.When diameter is fixed, we can find greater MRR with larger rotation speed, power and feed rate. 3.Experimental planning based on OA of Taguchi Method has both advantages and disadvantages as follows: (1) to arrange the least number of experiment to attain the best experiment efficiency; (2) simple an d quick analysis; (3) it is a drawback which can not be used to analyze multiple objective.

In common machining, the fracture toughness usually depends on bulk properties, such as the domain strength and the grain boundaries.
A number of researchers have focused on metal surface deformation, and fracture mechanisms have been discussed at length.

The number-average (Mn) and weight-average (Mw) molecular weights of P3HT was 17,028 and 31,528, respectively.
The microwave-annealed film also showed increased grain size with an rms value of 0.63 nm.

When repeatedly braking, each time the heat generated by braking cannot shed, it can make the temperature of the brake increase gradually, But the influence factors of thermal condition is too many, and the braking time is too short , the heat is difficult to shed, we can think that the temperature rise by braking is absorbed by brake , a short time due to the braking process, the heat difficult to shed, For non-metallic friction linings, the heat absorbed is too little for its insulation heat properties, so the most of the heat is absorbed by the brake disc, while braking each time , the temperature rise of the brake disk is: Where: - the ratio of the distributive heat of the single brake disc accounted for the total number of heat; -mechanical equivalent of heat 4.18 (J/card); -brake disc mass (kg);-the specific heat of the brake disc (J/kg•k).Which can be determined as follows: Where: - Brake disc diameter (mm); - brake disc thickness (mm); -the density of the brake disc (kgm-3
It can form transfer membrane, "brake thermal depression" and "hydrogen embrittlement" can occur, promoting the formation of grain, and the wear increasing.

The tool life at cutting speed of 60m/min is almost twice than that of 120m/min, and the tool life is decreased with the rise of cutting speed, which may attributes to the cutting temperature is increased with the rise of cutting speed at the same time, the high temperature softens the Co adhesive of PCD, which causes the diamond grain spalling from the PCD tools, and the tool wear increases immediately.
At the same time, the number of reinforcement contacting with PCD tools is increased per unit time, which aggravates the tool wear naturally.

The main points are followed as: The mending and exploring for the method of preparing, many new special arts are used in the growing of ZnO; The special phenomena for only small scale grains, the quanta limiting region domino effect; Excellent character of photoelectric of ZnO material; The system of compound material modulated and amended on the basis of ZnO; The nanometer framework of ZnO growing by self organizing that have special configuration and character; The foreground and appliance exploitation of ZnO material To achieve the requirements of different applications, many techniques, such as hydrothermal method [6,7], vapor phase method have been used to grow bulk ZnO crystals[8]; Magnetron sputtering (MS), chemical vapor deposition (CVD), molecular beam epitaxy (MBE), pulsed laser deposition (PLD), sol-gel process have been used to deposit ZnO films[9].
Tab 1 shows the particular conditions of the method ： Tab 1 The techniques for sheet nanometer ZnO prepared by zinc sulfate and nickel sulfate Sample number Conditions of precipitation reaction Conditions of form crystal Conditions of decompound c[ZnSO4] / [mol·L-1] n[NiSO4] /n[ZnSO4] T/℃ t/h v[ROH] /v[H2O] T/℃ t/h T/℃ t/h S-1 0.1 1:99 72 1.5 3:7 70 48 S-2 0.1 1:99 72 1.5 0 70 48 S-3 0.2 1:99 72 1.5 1:1 70 48 400 3 S-4 0.2 0.4:99.6 72 1.5 1:1 70 48 400 3 S-5 0.1 1:99 72 1.5 1:1 70 48 400 3 S-6 0.2 0 72 1.5 1:1 70 48 400 3 S-7 0.2 5:95 70 2 1:1 68 48 S-8 0.2 2:98 70 2 1:1 68 48 Optimize the precursor samples by XTJ30-micro image manipulation system, Fig1 shows the optimum sheet precursor sample: sample S-5 have larger transparent hexagonal sheet structure, very thin, have about 190-430μm widths.

(1)Coarse aggregate: continuous graded broken stones with the grain size of 5 to 26.5mm； (2)Fine aggregate: medium sand, fineness modulus of 2.67； (3)Water: clean tap water.
Financially supported by self-determined and innovative research funds of WUT Project number:135206006,2012-Ⅳ-070 References [1] Joseph Davidovits, Geopolymers and Geopolymeric Materials [J].Journal of Thermal Analysis, Vol.35, No2, 1989. 429-441