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,}, where t is the number of the found candidate topic features of each sentiment feature.
,Un}, where n is the number of all the Sentigrams. 3) Mine the frequent item set in Upair using association rule mining algorithm, find the most likely k features according to experience support degree minsup.
Ra = num[opi-ontology in Oj-ontology]/ op-num[Oj-ontology] (4) Where op-num[Oj-ontology] is the number of opinions in reviewj.
We use it to rank the opinions in reviews and choose the same number of opinions with generated summary opinions.
Modeling online reviews with multi-grain topic models.

The microstructure is composed of relatively dense structure with grain size d < 1µm and nanosized pores confirming gas adsorption results.
Fig. 1 SEM microphotographies of BCP ceramic granules In vivo evaluation of control group animal bone samples showed decreased number of long, thin bone trabeculae intermixed by bone marrow.
Also the number of osteocytes was notably decreased.
IHC evaluation of experimental group bone samples presented stably increased number of OC positive cells more than twice in all cases as to compare to the control (Fig. 2).
However, increase in number of OP containing osteocytes was less obvious.

Higher speed reduces grain boundaries, facilitating electron transmission and increasing film crystallinity [9], inducing π-π stacking for improved molecular structure.
The FTIR software calculated the absorption peak areas, representing the number of chemical bonds.
Figure 8 shows the increased number of Quinoid molecules in the high-resistance state facilitates an easier transformation to the low-resistance state after irradiation.
Devices adjusted in the process exhibit prolonged data retention time due to an increased number of conduction paths formed by Quinoid molecules, surpassing other control groups over time.
The physical property results from FTIR confirm an increase in the number of Quinoid functional groups in the PI film.

Surface roughness Ra /µm Grinding wheel 0 5 10 15 20 0.08 0.10 0.12 0.14 0.16 0.18 0.20 0.22 0.24 0.26 0.28 Grinding condition: vs=26.95m/s, vw=15m/min; Grinding wheel: w10; Ultrasonic parameters: Px=65W, fx=19.86KHz, Py=72W, fy=20.46KHz; Workpiece material: Nano-ZrO2; Common grinding Ultrasonic grinding Surface roughness Ra /µm Pass number of zero depth-of-cut grinding Fig. 4 The influence of wheel type on Ra Fig. 5 The influence of pass number on Ra Experimental Analyzing.
And in Fig.5, the surface roughness has a descending trend along with the inrease of pass number of zero depth-of-cut grinding.
And when the pass number is less than five, it will have great impact on surface roughness; while the value of the surface roughness improves more and more slowly when pass number exceeds five.
The grinding depth, the work piece speed, the grain size of diamond wheel and the pass times of zero depth-of-cut grinding, etc., have different effects on the machined surface roughness of the nano-ZrO2 ceramics.

This means that different deformation mechanisms may operate, included dynamic recrystallisation and grain boundary sliding, generating different flow curve shapes.
Obviously, the difficulty to calculate the coefficients of the polynomial equation may increase with increasing the number of variables, that are the factors governing the process.
Equivalent stresses (s) and deformations (e) were derived from t and γ using the von Mises criterion: (1) (2) where M is the torque, N the number of revolutions, n () the work hardening rate and m () the revolution rate sensitivity of torque.
The second strategy allowed the reduction in the number of the significant independent variables down to those reported as follows: x1=e, x2=, x3= T2, x4=e2, x5=.
Therefore, the proposed methodology allows the obtaining of regression models to supply as an input for finite element simulation of extrusion processes reducing, also in the model preparation phase, the number of time consuming and expensive microstructure tests.

There is significant experimental evidence to show that S-N curves are strongly dependent on the microstructure of the material, such as grain size, porosity and other defects, and as a result, S-N curves often exhibit significant scatter [3-5].
To understand the statistical variability of fatigue results, a number of studies have been carried out to establish an optimum experimental procedure for measuring S-N behaviour.
The replication levels are dependent on the number of stress amplitude levels (L) tested and the number of specimens (ns) used in the testing program, and are characterized by the percent replication (PR) that can be calculated by [2,6]: (1) ASTM E739 recommends replication levels of 17-33% for developing preliminary data and 75-88% for developing reliability data.
Fig 2b shows clearly that while the linear relationships based on percent replications of 45% and 50% are the same, the improvements from replication are minimal although the number of specimens used was doubled.
With such a small number of specimens available and to keep the replication requirements for particular purpose, e.g. 33 – 50% for research and development and 50 – 75% for design allowable data tests, the tested stress levels will be constrained and as a result, may not be enough to detect the whole picture of the S-N curves.

Introduction The number of civil transport aircrafts that comes to the end of the initial design life is continuously increasing Worldwide.
The wing panels under study were fabricated in laminated plates, in such a manner that the longitudinal orientation of the grains is collinear with the longitudinal direction of the wing.
Fig. 3 : Normalised S-N curves expressed as the ratio of the maximum stress divided by ultimate tensile stress as a function of the number of cycles to failure.
However, the large number of facets and their presence sometimes far from the initiation site suggest that they cannot systematically correspond with a sub-layer initiation process.
In addition, no clear trend can be found in the number of facets, their density or their surface, as a function of the studied material.

Choosing Experimental Samples and Numbering In order to study on impact resistance performance and test method of PDC, five common typical macro-interfaces (planar structure, v-groove, u-groove, ring groove, ring claw-tooth) are used as objects of this study.
Table 1 Samples’ serial number and their picture Number 1# 2# 3# 4# 5# Interface Planar structure v-groove u-groove Ring groove Ring claw-tooth Picture The Research for Test Methods of PDC Impact Resistance The impact resistance performance of PDC indicates its comprehensive performance, and is of crucial importance to PDC application effect.
Table 2 Test result of PDC impact resistance at normal temperature Samples number Interface structure Impact frequency Total impact energy 1# planar structure 20 78.4 2# v-groove 45 176.4 3# T-groove 70 274.4 4# Ring groove 90 352.8 5# Ring claw-tooth 130 509.6 During the drilling process of PDC tooth, there are two critical temperatures for the tooth’s thermal wear, 350°C and 750°C.
Table 3 Test result of the impact resistance performance of PDC after heating Samples number Heating temperature(℃) Heating time (min) Impact frequency Total impact energy Change of impact Energy (%) 1# 750 1 15 58.8 -25 2# 750 1 37 145.0 -17.8 3# 750 1 60 235.2 -14.3 4# 750 1 77 301.8 -14.4 5# 750 1 118 462.6 -9.2 SEM Test and EDAX Test Result for Interface Structure Through SEM photos and analyzing elements on PCD axis by EDAX, we can observe the combination state of interface structures.
Most of grain boundaries in diamond have formed D-D combination, which makes the psychical combination between WC-Co and diamond becomes a chemical combination WC-Co-D.

Describing the rock crushing process from fractal point as follows: rock mass broken into subset blocks with finite number and similar shape .Some of these subset blocks has been broken into more subset blocks with similar shape .And each time for repeating this process has produced smaller blocks .According to the probability and similar ratio of rock broken and the volume for different grain size, it can be drawn: Fund: This article is funded by the National Natural Science Foundation of China(rock damage evolution under Hydraulic fracturing and forming mechanism of micro-cracks No. 50974028) 3 0 bD k k R y R −   =     (1) Where: yk--accumulation volume ratio which fragmentation less than or equal to Rk; Db--fractal dimension of broken blocks [1].
The fractal dimension calculation of rock mass damage and fragmentation So far the sieving method is used to calculate the fractal dimension of rock mass damage fragmentation, but a great number of labor power and material resources will be spent.
The calculation of rock damage variables After rock broken, there are a large number of internal cracks, pores and other microscopic structures.
Where λstands for the mathematical expectation of the damage volume element number per unit volume.
According to Poisson's law, which is satisfied by the probability of damage volume elements, it can be drawn the probability with no damage in the volume V, and probability density of rock damage volume element can be gained: ( ) V V e λψ λ −= (4) If using Di to represent the rock damage variable, if we make λ=1/Va , the following formula can be established: ( ) ( ) ( ) 0 0 1 1 1 1 d a d m m V Vd V a i V V m V e V V dV V D V e V V dV λ ψ λ ψ − −   − +    = = − + ∫ ∫ (5) Where:Vm--The bulk volume of the rock, m3; Vd--The damage volume of the rock，m3;Va--The average volume of broken rock，m3;λ--The number of rock joints and cracks[3].

These were carried out in 0.01 M NaCl and 0.1 M Na2SO4 aqueous solutions, after mounting the samples as electrodes, in order to permit comparisons with results in the literature for 318 Journal Title and Volume Number (to be inserted by the publisher) other magnesium alloys, e.g. [3].
The only feature to notice is the increase in peak intensities of the Mg2Si phase and a decrease of its full width at half height (grain size increasing).
Units] Journal Title and Volume Number (to be inserted by the publisher) 319 (a) (b) Fig. 2.
These pits were even detected (in small number) in the samples tested with the less aggressive sodium sulphate solution.
Journal Title and Volume Number (to be inserted by the publisher) 321 Conclusions The experimental results shows that the corrosion resistance of the Mg60Ti10Si30 alloy is higher than that of Mg88Ti5Si7, which is explained in terms of chemical composition and changes in the alloy microstructure occurred during milling and subsequent heat treatment.