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Online since: January 2005
Authors: Zhi Shou Zhu, Chun Xiao Cao, Ming Gao Yan
The cyclic number at which the applied load drops to 30% of its starting value was considered as fatigue life, Nf.
If the number of cycles to initiate a crack of length ao is N1 and the number of cycles to propagate the crack to a critical crack size af is N2, the number of cycles to failure Nf can be represented by Nf=N1+N2 (1) The curve of maximum tensile stress versus cyclic number N is shown in Fig. 2.
When the total strain amplitude is as high as ±1.5%, a definite saturation stress is observed after slow cyclic hardening during the first several cycles Fig. 2 Cyclic stress behavior as a function of the number of cycles N Effects of Test Temperature.
Unlike the results observed in superalloys where the reduction of fatigue life is caused by oxygen embrittlement of the grain boundaries [11, 12], the environmental effect on the fatigue life is little in Ti60 alloy because of its transgranular crack initiation and propagation mode.
Online since: September 2013
Authors: Da Peng Yao, Ben Hai Zhou
A sensor node might vary in size from that of a shoebox down to the size of a grain of dust, although functioning "motes" of genuine microscopic dimensions have yet to be created.
Although some multi-core processors, such as Intel’s Core Duo, allow measuring the number of cache lines allocated to each co-runner, they provide no mechanism to enforce fair cache sharing.
The expression for is: (2) L2MissPI denotes the number of cache misses per instruction; L2CopyBackPI represents the number of transactions (per instruction) writing dirty cache lines back to memory; MemoryLatency equals memory access time required to fetch a cache line and memory-bus delay per memory transaction.
StoreBuffLatencyPI presents the number of cycles per instruction a processor latency on a store buffer Now, we can calculate the, where and can get from performance hardware counters.
The relationship between the co-runners’ miss rates for a processor with n+1 cores is presented by equation (5) (5) Where is a thread for which we compute the fair miss rate, is the ith co-runner, is the number of co-runners, and a and b are the linear equation coefficients.
Online since: February 2014
Authors: Xun Wang, Zhi Li Pei, Jian Hong Qi, Li Sha Liu, Qing Hu Wang, Ming Yang Jiang
Reuters-21578 corpus distribution table Category number Category name Text number C1 Eam 3762 C2 ACQ 2334 C3 MoneyFx 694 C4 Grain 561 C5 Crude 591 C6 Trade 511 C7 Interest 495 C8 Wheat 294 C9 Ship 297 C10 Corn 247 Corpus preprocessing This paper adopted the Chinese morphology system ICTCLA developed by Chinese Academy of Sciences to the text segment processing in corpus database.
The accuracy comparing figure based on KNN classifier It is observed by figure above that the classification effect of DF method is better than that of MI, IG, when feature number is below 7000.
The classification accuracy of CHI method is better than that of MI, IG and DF when feature number is below 5000.
But that of DF method is better than that of MI, IGand CHI when feature number is above 5000.
Online since: December 2012
Authors: John Mo, Song Lin Ding, Wen Cheng Pan
The grain size of CTB010 is 2 - 30 μm, the elastic modulus is 890-900 MPa, the hardness is 50 Gpa (8000 HV), the density is 4.12 g/cm3, and the thermal conductivity is 540 w/mk.
Fig.1 PCD tool for experiment Table 1 Geometrical parameters of cutting tools Tool number Front angle Cutting edge angle Clearance angle 1 1 6 8 2 1 8 12 3 1 10 14 4 2 6 12 5 2 8 14 6 2 10 8 7 4 6 14 8 4 8 8 9 4 10 12 Helix angle 10o To analyze the effects of front angle, clearance angle and cutting edge angle of the tool, the theory of orthogonal cutting was used.
Fig.2 Experimental system setup Table 2 Cutting forces (Unit: 600.6N/V) Tool number Fx Fy Fz Resultant 1 0.0645 0.0466 0.0251 0.0834 2 0.0814 0.0538 0.0263 0.101 3 0.0869 0.0524 0.0242 0.1043 4 0.0753 0.0521 0.0248 0.0948 5 0.0693 0.0512 0.0228 0.0891 6 0.0805 0.0475 0.0214 0.0959 7 0.0875 0.0503 0.0187 0.1026 8 0.0837 0.0527 0.0202 0.1009 9 0.0418 0.0276 0.0326 0.05 Assume Ⅰi, Ⅱj, Ⅲk are the sums of the three levels of a factor: · Front angles: Ⅰ1 represents resultant force when front angle is 1o; and Ⅱ1, Ⅲ1 represented the force when cutting speeds are 2o and 4o, respectively
Assume S1, S2 and S3 are the changes of three factors: (1) where: yi is the force of each test, n is the number of level replications (for this case, n = 3); m is the number of levels (here m = 3).
(2) where: t is the number of tests.
Online since: July 2011
Authors: Wei Qiang Wang, Jie Tang, Xiao Hui Ma, Meng Li Li
There are still a number of small cracks at the same axis, as shown in Fig.4.
As shown in Fig.11, there are a number of cracks in the surface of sample A, which are not continuous, no fork, basically parallel to the axial heat exchanger, extending to both sides.
A number of small cracks can be connected into a large crack.
In addition to a main crack, there are a number of small transgranular cracks.
Spiral plate microstructure is single-phase austenite grain, which is a normal 022Cr19Ni10 microstructure after solution treatment, transgranular cracks without bifurcation.
Online since: July 2011
Authors: Jing Kun Yu, Zhi Qiang Li
Theoretical Analysis Titanium has been widely used for thinning grains.
The formation of TiO2 micro-inclusions decreases the number of [Ti] which should be used to combine [C] or [N], and increases the number and size of complex oxide by providing basis for heterogeneous nucleation.
Either deep deoxidation or strictly controlling the mass of Ti-Fe alloy added into steel through measuring dissolved oxygen content online would be effective methods to decrease the number and size of Al2O3-TiO2 complex oxide and TiO2 simple oxide.
It would be available for decreasing the number and size of micro-inclusions to control the number of wTi·wO2 less than 3.96×10-08 before steel begins solidification through certain methods.
Online since: July 2008
Authors: Boris Aberšek, Jože Flašker
We performed a few test for each loading ratio, which facilitated studying of a great number of cracks.
During fatigue we measured by means of strain gauges the change of strain as function of number of cycles in the area of micro cracks.
The number of cycle's waried from 0 to 280.000 where the test was stopped.
The data on this lining are: deformation optical constant F = 4,10x10 -6 m/rad, module of elasticity E=2900 MPa, Poisson's number n=0,36 and thickness of lining h=2 mm.
From fractography we can establish that the crack length-number of cycle's ratio is not a continuous smooth. 2.
Online since: July 2008
Authors: Norio Kawagoishi, Y. Sofuku, M. Adachi, K. Okutani, Y. Maeda
Results and discussion Fig. 3 shows the S-Nf curves (Nf: number of cycles to failure).
As seen from the figure, in the process of propagation in tensile mode, the relation between the logarithm of crack length and the number of cycle was approximated by a straight line, meaning that the crack growth rate is proportional to the crack length.
S-Nf curves 10 4 10 5 10 6 0 50 100 150 200 250 糫 糫 S-Nf curves RH25% RH85% Strees amplitude, 〉a MPa Number of cycles to failure, Nf cycles Fig. 5 shows the crack growth rate against for the term σanℓ.
The reason may be explained from that a crack of the present alloy initiated at the early stage of fatigue life even in low humidity as mentioned above, consequently the effect of humidity on the crack initiation was very small. 0 1x10 5 2x10 5 3x10 5 4x10 5 5x10 5 6x10 5 7x10 5 0.01 0.1 1 10 Coalescence of cracks Crack length, l mm Number of cycles, N cycles RH 25% 220MPa 200MPa 180MPa 160MPa 140MPa 0 1x10 5 2x10 5 3x10 5 4x10 5 5x10 5 6x10 5 7x10 5 0.01 0.1 1 10 Number of cycles, N cycles Coalescence of cracks Crack length, l mm RH85% 220MPa 200MPa 180MPa 160MPa 140MPa Fig.4 Crack propagation curves 10 7 108 10 9 10 10 10 -9 10 -8 10 -7 10 -6 RH25% RH85% 1 1 Crack growth rate, dl/dN m/cycle 絓ー膄絙縕l , (MPa) 5 m Fig.5 Crack growth rate against for the term σanℓ Fig.6 Morphology
zigzag manner being affected by microstructures like a eutectic Si, segregated Si particles, grain!
Online since: November 2011
Authors: Li Li, Hong Yin Xu
This is because active site relatively small in system when the concentration of small, the relatively large number of monomer around, easy to generate a large number molecular polyaniline, and acid doping is not sufficient, so when the concentration increase, it generate more and more acid doped polyaniline; When concentration of the acid or oxidant is too high, the sulfosalicylic acid may hinder the polymerization of aniline, and active site relatively much in system, the relatively small amount of monomer around, is not conducive to generating macromolecular polyaniline.
(a)after 64 hours morphology (b)after 124 hours morphology Fig.3 Corrosion morphology of same formulations and in the different time Figure3 are the corrosion morphology of coating by the 64 hours and 124 hours at the same time, the surface of two pictures are coarse, but B1b have small grains, it could be caused by intergranular or pitting corrosion, it can be seen that the corrosion of B1b is more severe than B1a, it because the longer of corrosion time, the greater of corrosion degree.
Fig. 4 After 64 hours morphology in different formulations The figure shows, the number of Black spot and air gap on the surface of E1a and B1a is more than D2a and C3a, and black spot much big and deep, it can be seen that E1a and B1a are more severe corrosion than D2a and C3a.
Because of the oxidant and dopant acid concentration of C3b formulations is moderate, the number of synthetic molecules is moderate, doped fully and corrosion-resistant of synthetic polyaniline is strong.
Fig.6 The polarization about different samples in 3.5%NaCl solution at room temperature Table3 Corrosion potential and corrosion current parameters of different samples (room temperature) number Ecorr (V) Icorr (A/cm2) logI (A/cm2) B4 ﹣0.8426 1.4197×10﹣5 ﹣4.8478 C3 ﹣0.5548 6.1038×10﹣6 ﹣5.2144 D2 ﹣0.7451 9.6516×10﹣6 ﹣5.0154 From the Figure 6, △Ecorr(C3)>△Ecorr(D2)>△Ecorr(B4)that is the highest the corrosion potential of the sample C3.
Online since: December 2011
Authors: Wei Juan Li, Jue Hou, Li Wen Zhang, Lan Jin, Xin Dong
The microstructure of tested steel is ferrite and second-phase particles, the level of the grains is 7.
Add to the number of movable dislocations did not change more, so BH value no change basically.
Due to the increase of dislocations, the number of "Cottrell atmosphere" is also increased.
This is due to the small strain can make the steel plate produce a small number of new dislocation and formed the "Cottrell atmosphere" with solute atom, so as to improve the bake-hardening value.
It will reduce the number of free dislocation instead and the number of formatting "Cottrell atmosphere" will decrease, so as to reduce the BH value.
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