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A large number of the conducted studies have been carried out on artificially cracked specimens, and various methodologies of the controlled crack introduction were presented; however, no specific method was clearly preferred.
For this reason, in studies dealing with cracking-related topics, a large number of various methods of natural crack induction has been presented.
For the specimen preparation, the following materials were used: ordinary Portland cement CEM I 42.5 R (Závod Mokrá, Czech Republic) in a dosage 586 kg/m3, standard tap water with water to cement (w/c) ratio 0.5, fine aggregates with maximum grain size 1.0 mm (1319 kg/m3) and medium aggregates with maximum grain size 2.0 mm (440 kg/m3), both obtained from Provodínské písky a.s., Czech Republic.

During choosing the initial clustering number, the paper references the characteristics of users, first select an appropriate number of clustering and analysis through clustering results, then adjusting the cluster number, seeking to achieve optimal clustering effect.
Where represents the satisfaction degree of interaction, represents the number of interaction.
(2) The number of interaction.
We use the interval number of interaction as the attenuation factor.
A fine grain trust model based on domain and Bayesian network for P2P E-commerce system [J].

The laser beam power was fixed at 50W and the number of runs (superposition of tracks) varied on the sample.
Fig. 1: MEV of the starting material, thin graphite powder with 3 micrometers of average grain size.
As can seen in Table 1, the AISI M2 samples were irradiated with two different laser beam sweep speed values, whereas each one of them was irradiated a certain number of times or number of heating cycles, which are 3, 10 and 20 times.
Fig. 4 shows the dependence of the laser intensity and the number of irradiations of a sample covered by a graphite layer.
Normal loads: 5N, track size: 6 [mm], pin sliding velocity: 10 [cm/s], turn's number: 2000, time of test: 13'14".

Table 1 Mechanical parameters for the model Elastic modulus Compressive strength Poisson ratio Weibull parameters Mean value [MPa] Homogeneity index Mean value [MPa] Homogeneity index Mean value Homogeneity index glass 73000 7 800 7 0.22 100 Table 2 The numbers of failed elements in the model failure process λ =0.0 λ =-1.0 λ =1.0 Step Number of failed elements Cummulated number of failed elements Step Number of failed elements Cummulated number of failed elements Step Number of failed elements Cummulated number of failed elements 50 0 0 69 0 0 78 0 0 51 1 1 70 1 1 79 1 1 52 0 1 71 0 1 80 0 1 53 0 1 72 0 1 81 0 1 54 1 2 73 1 2 82 1 2 55 0 2 74 0 2 83 0 2 56 0 2 75 1 3 84 1 3 57 0 2 76 0 3 85 0 3 58 0 2 77 1 4 86 0 3 59 1 3 78 1 5 87 1 4 60 0 3 79 2 7 88 0 4 61 2 5 80 1 8 89 0 4 62 0 5 81 4 12 90 2 6 63 2 7 82 2 14 91 1 7 64 0 7 83 3 17 92 1 8 65 2 9 84 4 21
For the three models in this paper, the numbers of the failed elements are shown in Table 2.
Table 2 shows that, the crack growth rate will change from the state of subcritical crack growth to the state of unstable growth when the total number of failed elements reaches a certain value (see the bold numbers in Table 2).
Thus, the critical stress intensity can be determined by the change of the numbers of acoustic emission.
For instance, the plastic areas of the crack tip, the crack-bridge and pulling out of grains may improve resistance [22].

Using chitosan as raw material,the modified chitosan was obtained through alkylation reaction with alkyl halide, which as a carrier, Cu2O/ modified chitosan composite photocatalyst was prepared by hydrazine hydrate reduction.Using the method of X-ray diffraction and scanning electron microscope analysis, characterization of the composite photocatalyst show: Cu2O loads evenly on the modified chitosan, and the structure of Cu2O changes little, grain size of Cu2O is about 200nm~300nm.Using UV mercury lamp as the light source, alizarin red as target degradation product, photocatalytic performance of the Cu2O/modified chitosan photocatalyst was researched.The results show that: As the loaded modified chitosan produces a synergistic effect with Cu2O, its degradation rate of the dye improves in the UV mercury lamp,when the concentration of alizarin red is 50mg/L of the experimental conditions, the composite catalyst dyedegradation better than separate Cu2O catalysts and modified chitosan
Figure 1b shows, the molecular structure of chitosan, large number of hydroxyl and amino distribution in its molecule, hydrogen bonds formed between them, resulting in crystallinity chitosan molecules is very strong.

The grain size was about 10 nm and the specific surface area of the powders ranged from 160 to 166 m2/g.
Gai proposed employing passivated co-doping nonmetals and metals to enhance the visible light response based on first principle electronic structure calculation[5] and a number of original experimental works on co-doped TiO2 have been reported [6-8].

By electron energy spectrometer,X-ray diffractometer,transmission elec-tron microscopy andmicro-hardometer,the depositing speed of electrolessNi-Co-P plating baths,chemical composition,crystal structure and microhardness of the alloy coatings were inspected and analyzed with ultrasonic and rare earth metalcerium intervening in electroless Ni-Co-P plating·The results show that the depositing speed of electroless Ni-Co-P plating isobviously increased under the effect of ultrasonic.The chemical compositions of electroless Ni-Co-P plating are changed，The XRD of coating has a diffuse sexual diffraction peak closing to typical amorphous structure.the obtained Ni-Co-P coating has more fine crystal grain, even and dense surface morphology.
Thirdly, instant high temperature generated by cavitation effects increases molecular collisions, increases the number of molecules, making activated molecular ratio increases and also accelerates deposition rate of metal ions. [10-11] After joining ultrasonic, coating hardness also rises and quality loss also reduced correspondingly, thus the abrasion resistance of coating improves.

Research on the Wall Crack Grouting Technology of Brick-concrete Structure Bin Jia1, Ke Li1, Xiao Liu1 , Naiqing Meng2 1School of civil Engineering and Architecture, Southwest University of Science and Technology, Mianyang 621010, China 2The construction engineering earthquake office of Tibet autonomous region, Tibet Lhasa 850000,China Keywords: Masonry structure, Cracks, Grouting Abstract: Wenchuan earthquake caused a large number of masonry structure cracks, crack grouting become a very important link in the process of engineering structure reinforcement repair.
Sand grain size mortar is set according to the situation, generally used in the medium sand and medium sand in the following.

In fig. 2, The comparison of material’s grain size is optimized by the thulium metalation.
(a) before optimization (b) after optimization Fig. 2, The comparison of material’s grain size before and after optimization by thulium metalizing Research content of optimizing heat treatment is: 1) Adopting vacuum heat treatment to reduce oxidation when heating; 2) Adjusting quench temperature to change metallizing degree and enhance the hardenability; 3) Adjusting the temper parameter to enhance the effect of secondary hardening.
Main technical parameters of dual liquid centrifugal casting instrument Serial number Title Unit Value 1 Power of electromotor kW 6.4 2 Rotate speed of electromotor r·p·m 800~1800 3 Diameter of the bimetal cylinder liner produced mm ≤200 4 Maximal producing ratio hour-1 4 5 Maximal force of thrusting upward ton 20 6 Outside parameters of the machine(Long×Wide×Height ) mm 4800×1500×1700 7 Total weight of the machine ton About 1.8 Dual liquid centrifugal casting instrument’s main trait is: 1) There is a brake decelerate arrester, it can adjust rev more quickly; 2) Adopting AC bunch to realize stepless speed regulating in a certain range; 3) Adopting single controller which could program to realize program control; 4) Applicable to produce various cylinder liners whose diameter is below 200mm (need to change cylinder liner mould).

A large number of small spherical wear debris in fretting scar are observed at the locations A,B and C in Fig.2(e), which can be judged as mainly black aluminum oxide according to table 1.
Fig.3(b) also shows that this zone is fine-grained, smooth and beach-like.
This zone has high roughness with some impurities in the bottom of the pits which are related to the weakness of grain boundaries.