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Online since: March 2007
Authors: Christian Moreau, Jorg Oberste Berghaus, Jean Gabriel Legoux, Rob Hui, Dave Ghosh
Multiple SOFC components, including the electrodes and the electrolyte, could be produced sequentially and directly on a metallic interconnect substrate with a single deposition technique, thereby minimizing the number of processing steps and equipment required [6].
Thin coatings (3-20 µm) with a more refined microstructure and grain size than in conventional thermal spraying are thereby created [7,8].
At the short spray distance and proximity to the plasma flame, a careful thermal management, which reduces the tensile stresses created by the solidifying droplets as well as the overall thermal stresses in the assembly, was found critical to prevent vertical crack Volume % NiO-SDC nGimat DRY Particle Diameter (µm) 0.3 0.5 2 3 5 20 30 1 10 Number % 0.01 0.1 1 10 Volume % NiO-SDC NextechDRY Particle Diameter (µm) 0.3 0.5 2 3 5 20 30 1 10 Number % 0.01 0.1 1 10 Fig. 1: Particle Size of NG and NT feedstocks (NiO-SDC) 5 µm Crofer 22 APU SDC layer (a) (b) formation [9].
The grain size in the coating was estimated to be below 40 nm.
Online since: November 2015
Authors: U.S. Mallikarjun, T. Lokesh
Literature survey reveals [2-4] that although a number of light metals such as Al, Mg, and Ti have been used as matrices, mostly Al and its alloys both cast and wrought alloys have been used more extensively as the matrices for MMC synthesis.
A good number of research works have been carried out on the Al/SiCp and Al/Graphite individually.
d c a b 100µm Fig. 1: Microstructure showing the distribution of particulates and grain boundaries a) Base Al6061alloy b) Al6061-4wt.
This is due to soft nature of the graphite particulates which made the material to become ductile rather than brittle, and also due to the lubricate property of the graphite which eases the movement of grains along the slip planes [17].
On the other hand, the graphite reinforced composites [Fig.5 (b)] showed the ductile nature of fracture with less number of dimples on the surfaces.
Online since: March 2012
Authors: Hua Zhu, Fei Hu, Hui Wen Liu, Peng Xing, Xiao Wei Feng
When titanium dioxide membrane is thin, the number of molecules of the dye absorbed is less, and it is not enough to completely absorb the incident light.
And when the membrane is very thick, although the number of molecules gets more, the opportunity that absorbs electronic and nanoparticles trap or for the surface to get composited will increase during transmission, thus it becomes difficult to deliver REDOX electricity in TiO_2 3d network structure.
Only a certain number of dye molecules can be restored by ion I can limit the light current and efficiency, thus leading to bigger current lose.
If the life span of the electronic light were 2*10-2 and it’s diffusion coefficient of electricity are become 5*10-5 cm2/s during TiO_2 grain, thus the diffusion journey of electricity can be calculated follow the following equation: ,and the result is 10 .
Thanks to the thin films they particle diameter, pore size and grain type influence is bigger, the heat treatment process need to control the time of heat and calcining temperature, etc, the right time of heat and calcining temperature is good to the perfect type of sharp titanium ore nanostructured jingjing.
Online since: May 2014
Authors: Laurent Dubar, Michel Watremez, Kevin Le Mercier, Laurence Fouilland, Jean Dominique Guérin
Zener-Hollomon number.
Each rheological parameter of both models is expressed by a power law of Zener-Hollomon number [2] expressed in Eq.1 coupling temperature T and strain rate ε.
σy= σWH+DR- σDRX σWH+DR= σ0+σp-σ01-exp-Cεpm εp< εpeak , σDRX=0 εp≥ εpeak , σDRX=σp-σsXDRXεp-Xεpeak1-Xεpeak XDRXεp=1-exp-εp-εcε*m' σ0,σs,σp,C,m,m',εc,ε*=fZ with fZ=KiZmi Figure 6: Kim et al.’s model. [6] The σDRX term involves the volume fraction of dynamically recrystallized grains XDRX which relies on an Avrami equation.
Fig.7 shows double logarithmic plots of the peak stress σp and the steady state stress σs as function of Zener-Hollomon number.
Furthermore, this model provides more details about the microstructural mechanisms involved through the volume fraction of dynamically recrystallized grains XDRX.
Online since: January 2015
Authors: Jin Tong, Hong Chang Wang
According to the UN food and agriculture organization (FAO) reported that the world’s food crops suffering from disease, insect, weeds and other harm, pre-harvest yield an average loss of 30 to 35 percent, and 10 percent of the loss caused by weeds, which about 290 million tons of grains [2].The losses caused by weeds accounted for about 10 percent in China, which about billions of kilograms of grain loss every year.
The number of the tines and revolving speed of the comb disc had significantly effect on the performance of the weeding unit.
The result showed that the best parameters scheme was: the number of weeding tines 6,and revolving speed 180 r/min,space between the tines 50 mm,work velocity 2.3 m/s, the injury seedling rate and weeding rate were 2.74 percent, 87.6 percent respectively.
On the one hand, increasing investment in technology research and development of intelligent, learning from foreign advanced technology and the design concept of intelligent weeding equipment, researching the intelligent weeing equipment which adapt to requirements of agronomic of China; on the other hand, the developed weeding machines should have multiple functions, which can reduce the number of mechanical into the field, save costs of research and manufacturing.
Online since: April 2010
Authors: Maria-Teresa Freire Vieira, Ana Sofia Ramos, Manuel F. Vieira, Filomena Viana, Sonia Simões
The heat treatments are also responsible for the grain growth, although at least up to 425ºC the size remains nanometric [9].
Several sets of experiments were designed in order to have a sufficient number of indentations in each region.
Several sets of experiments were designed in order to have a sufficient number of indentation tests in each region.
The values presented correspond to an average hardness, although the number of indentations in these layers does not justify the inclusion of standard deviation values.
The grain growth promoted at 800ºC compared with the lower heat treatment temperatures is responsible for this difference, as predicted by the Hall-Petch relationship.
Online since: August 2021
Authors: Yuri V. Dolgachev, Viktor N. Pustovoit
In austenite, there are regions with ferromagnetic order (ferromagnetically ordered nanoclusters), the number and size of which increase with decreasing temperature or upon application of an external magnetic field [13].
For a spherical embryo: (2) The formation work of a critical size nucleus is determined by substituting the value Rcr into Eq. 1: (3) The free formation energy of one ferromagnetic cluster (without considering the interface energy between the paramagnetic matrix and a atoms group with parallel spins) can be written as Df* = DF·V·I2·N0/VM, where VM is the molar volume, and N0 is the Avogadro number.
This is a consequence of the sufficient uncertainty and the dependence on a large number of the parameters Df, s, U, which are available in the literature and refer to such processes as decomposition of austenite in the pearlite temperature range and intermediate transformations, decomposition of retained austenite upon tempering.
During the nucleation of the initial phase at the grain boundaries, one should also take into account the contribution of the released excess the grain boundary energy, which reduces the formation work of the critical nucleus.
Online since: June 2022
Authors: Dianisa Khoirum Sandi, Fahru Nurosyid, Yofentina Iriani, Rindhi Afriani
Of these dopants, Mn is preferred due to its similar ionic radii with Ti4+ (rMn4+=0.67Å and rTi4+=0.68 Å) and the same coordination number of 6 [11, 13].
Besides, it can produce very small grain-sized particles in a relatively short time preparation.
The profiles confirm the STO phase based on ICDD number #860178.
According to ICCD number #221437, these peaks correspond to the phase of SrCO3.
Besides providing sufficient energy to react, high temperatures also increase atomic mobility, which would cause grain growth.
Online since: September 2008
Authors: Ren Ke Kang, Zhu Ji Jin, Ze Wei Yuan, B.X. Dong
However, the columnar growth of CVD diamond results in a polycrystalline nature and the grain sizes increases with film thickness.
The 1.4cm-1shift to a higher wave number indicates a compressive residual stress on the PCD specimen, because the Raman band of diamond moves to higher wave number shifts with increasing applied pressure [15].
As the polished area gets large, the pits of grain boundaries decrease therefore the better average surface roughness.
Raman Shift (cm -1 ) 1578 1377.8 679 after further polishing with diamond abresive after polishing with grindingwheel shift to a higher wave number indicates a compressive residual stress on the CVD diamond film.
Online since: February 2012
Authors: Chu Wang Su, Quan Ping Yuan, Yi Chen, Guang Xu Tao, Jia Yang
Table1 Dimension and numbers of samples Processing project Dimension:thick × wide ×long [mm] Numbers of samples [piece] Planning 19×102×910 30 Sanding 10×102×305 Testing and Evaluation Method.
The testing results showed that defects became more serious and the number of defects was increasing substantially with the feeding speed adding.
The machining quality of Magnoliaceae glanca Blume and Castanopsis hystri near the sub could be improved significantly through sanding, and planning defects(burr, chipped grain, raised grain, etc) were significantly removed at the same time, so sanding was a necessary processing for Magnoliaceae glanca Blume and Castanopsis hystri machining after planning.
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