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Online since: October 2015
Authors: Jian Meng Huang, Ning Li, Bin Wang, Wei Zeng Chen
There were coupling relation between metallic cations Ni2+(Mo4+) and OH- negative ion in preparation conditions, because the lower h.e. overpotential of Mo, the hydrogen evolution in electrolysis progress was obviously effecting the growth ability of forming grain, and forcing the crystal lattice breakdown, which forms a number of nuclei of atoms.
The nanocrystal size was extremely small, which lead to the grain boundary increase.
The nanocrystal size was extremely small, which lead to the grain boundary increase.
Online since: January 2016
Authors: Olivier Barrau, Fabien Nazaret, Marion Le Fournier, Etienne Lebard, Yannick Lemaoult
The superplastic deformations are possible in a narrow gap of temperature (870°C to 950°C for TA6V for fine grain and can be reduced to 750°C for Ultra Fine Grain alloys).
If any solution cannot be found, the cover design will be revised: the change of the number and the position of the lamps, the maximal power delivered and the type of reflectors.
If any solution cannot be found, the cover design will be revised: the change of the number and the position of the lamps, the maximal power delivered and the type of reflectors.
Online since: October 2015
Authors: Sergey L. Sinebryukhov, Dmitry V. Mashtalyar, Sergey V. Gnedenkov, Andrey S. Gnedenkov
To date, a large number of studies have been carried out to address corrosion issues and to improve the corrosion performance of Mg alloys [1,2].
All samples were mechanically ground for surface standardization with silicon carbide (SiC) papers with the decreasing of the grain size of the abrasive material down to 15 μm and further polished with aluminum oxide paper with the grain size down to 3 μm.
All samples were mechanically ground for surface standardization with silicon carbide (SiC) papers with the decreasing of the grain size of the abrasive material down to 15 μm and further polished with aluminum oxide paper with the grain size down to 3 μm.
Online since: November 2012
Authors: R. Veiga, Giovanni Borsoi, Martha Tavares, António Santos Silva
Fig. 1 – Grain size distribution of the different aggregates used.
However, limewater usually contains not more than 2 g/L of calcium hydroxide, that only guarantees a low consolidation effect, with a poor cementing action [2], unless it is applied in a high number of cycles.
According to previous studies [11], the carbonation of nanolime particles originate oriented crystal grains, which promote the agglomeration of particles, improving the cementing action, the cohesion of the particles and thus the mechanical strength of the treated surface.
However, limewater usually contains not more than 2 g/L of calcium hydroxide, that only guarantees a low consolidation effect, with a poor cementing action [2], unless it is applied in a high number of cycles.
According to previous studies [11], the carbonation of nanolime particles originate oriented crystal grains, which promote the agglomeration of particles, improving the cementing action, the cohesion of the particles and thus the mechanical strength of the treated surface.
Online since: August 2011
Authors: Jie Li, Bao Wei Li, Lei Wang, Jun Wang
To obtained the iron ore concentration, the tailings is usually handled by the methods of “magnetic roasting—low intensity magnetic separation” or flotation because the tailings have the disadvantage of low iron grade, lots of impurity and fine grain size.
Production practices and a large number of studies have shown that the best magnetic roasting temperature is about 750~850˚{TTP}730 C under conventional heating [12~14], and at this temperature range, the result of magnetic roasting is best and the productivity is higher.
In addition, because the molecule and atom of the minerals vibrate at high speed in microwave filed and the dielectric property of iron ore and Nb minerals are different from each other, there would be internal stress in the mineral grain [15, 16].
Production practices and a large number of studies have shown that the best magnetic roasting temperature is about 750~850˚{TTP}730 C under conventional heating [12~14], and at this temperature range, the result of magnetic roasting is best and the productivity is higher.
In addition, because the molecule and atom of the minerals vibrate at high speed in microwave filed and the dielectric property of iron ore and Nb minerals are different from each other, there would be internal stress in the mineral grain [15, 16].
Online since: February 2011
Authors: Hong Mei Wang, Li Xia Yuan, Yuan Lian
where D is the mean grain size, λ is the X-ray wavelength (for Cu kα radiation, λ=1.5406Å), β is the FWHM of diffraction peak and θ is the diffraction angle.
Based on the full width at half maximum of there flection planes(111, 220 and 311) in zinc-blend structure, the mean grain sizes of the undoped ZnS and Mn2+-doped ZnS particles as calculated by using Eq. (1) from the most intense peak were around 3.8 and 4.5nm, respectively.
Thus, the existence of Mn2+ pairs is important for the occurrence of the concentration quenching process; the excitation energy is transferred from one Mn2+ ion to its nearest Mn2+ ion by nonradiative transition and via a number of transfer steps, finally to a quenching site (such as defect state).
Based on the full width at half maximum of there flection planes(111, 220 and 311) in zinc-blend structure, the mean grain sizes of the undoped ZnS and Mn2+-doped ZnS particles as calculated by using Eq. (1) from the most intense peak were around 3.8 and 4.5nm, respectively.
Thus, the existence of Mn2+ pairs is important for the occurrence of the concentration quenching process; the excitation energy is transferred from one Mn2+ ion to its nearest Mn2+ ion by nonradiative transition and via a number of transfer steps, finally to a quenching site (such as defect state).
Online since: June 2011
Authors: Haris Al Qodri Maarif, Teddy Surya Gunawan, Afzeri Afzeri
Lastly, the quality scalability or Signal to Noise Ratio (SNR) scalability is approached by two different methods, coarse grain scalability (CGS) and medium grain scalability (MGS).
The GOP 16 was used which also automatically define the number of I, and P frames.
The GOP 16 was used which also automatically define the number of I, and P frames.
Online since: November 2005
Authors: Subrata Chatterjee, Brajendra Mishra, A. Ghosh
The
microstructures at various FRTs show predominantly lath martensite within pancaked grains and
comparatively finer lath size has been obtained for the steel processed below 800o C FRT.
In the present steels the Ti/N ratio were quite higher (~8) than the optimum level and thus large number of coarse TiN particles have formed. 740 760 780 800 820 840 860 400 420 440 460 480 Alloy1 Alloy2 Alloy3 Hardness (VHN) FRToC 740 760 780 800 820 840 860 1200 1300 1400 1500 1600 1700 1800 Alloy1 Alloy2 Alloy3 UTS (MPa) FRToC 740 760 780 800 820 840 860 1100 1200 1300 1400 1500 Alloy1 Alloy2 Alloy3 YS (MPa) FRToC 740 760 780 800 820 840 860 10 12 14 16 18 20 Alloy1 Alloy2 Alloy3 %Elongation FRToC Fig. 6.
Carbon Fig. 7 : Variation in mechanical properties of the alloys with respect to carbon content (e) Impact toughness at RT (f) Impact toughness at −40o C Conclusions The following conclusions can be drawn from the present study: 1) The microstructure of the TMCP steels shows predominantly lath martensite in pancaked grains.
In the present steels the Ti/N ratio were quite higher (~8) than the optimum level and thus large number of coarse TiN particles have formed. 740 760 780 800 820 840 860 400 420 440 460 480 Alloy1 Alloy2 Alloy3 Hardness (VHN) FRToC 740 760 780 800 820 840 860 1200 1300 1400 1500 1600 1700 1800 Alloy1 Alloy2 Alloy3 UTS (MPa) FRToC 740 760 780 800 820 840 860 1100 1200 1300 1400 1500 Alloy1 Alloy2 Alloy3 YS (MPa) FRToC 740 760 780 800 820 840 860 10 12 14 16 18 20 Alloy1 Alloy2 Alloy3 %Elongation FRToC Fig. 6.
Carbon Fig. 7 : Variation in mechanical properties of the alloys with respect to carbon content (e) Impact toughness at RT (f) Impact toughness at −40o C Conclusions The following conclusions can be drawn from the present study: 1) The microstructure of the TMCP steels shows predominantly lath martensite in pancaked grains.
Online since: March 2006
Authors: J. Baruchel, Guillaume Reinhart, J. Gastaldi, J. Härtwig, Henri Nguyen-Thi, Nathalie Mangelinck-Noël, Bernard Billia, Thomas Schenk
In alloy systems,
the contrast mainly results from segregation, which is proportional to the atomic number of the
components and their concentration [4].
In fact, it should be emphasised that cells are attached by a thin solid neck to the native solid grain as visible in Fig2a.
Grain polygonisation will subsequently occur due to the nucleation in the cell boundaries of arrays of dislocations extending along the growth direction where adjacent columnar bodies with slightly different orientation join.
In fact, it should be emphasised that cells are attached by a thin solid neck to the native solid grain as visible in Fig2a.
Grain polygonisation will subsequently occur due to the nucleation in the cell boundaries of arrays of dislocations extending along the growth direction where adjacent columnar bodies with slightly different orientation join.
Online since: February 2018
Authors: Zeng Lin Zhou, Qiao Juan Deng, Yan Li, Zhi Lin Hui, Fu Wang, Xue Liang He
From Fig. 2(a), it can be observed that the raw tungsten powder has relatively uneven grain size and irregular particle shape, ultrafine particles and ultra-thick “aggregates” existed.
In Fig. 2(c), it can be found that the grain size of classified medium powder is more uniform, and the phenomenon of “folder fine” or “folder thick” is almost disappeared.
This is due to the fact that the sintering process of tungsten is mainly caused by atomic diffusion and creep behavior, and with the increase of temperature, the number of active atoms in the particles also increases, leading to the increase of adhesive surface between particles and the growth of sintering neck, which is conducive to the improvement of porous tungsten’s intensity.
In Fig. 2(c), it can be found that the grain size of classified medium powder is more uniform, and the phenomenon of “folder fine” or “folder thick” is almost disappeared.
This is due to the fact that the sintering process of tungsten is mainly caused by atomic diffusion and creep behavior, and with the increase of temperature, the number of active atoms in the particles also increases, leading to the increase of adhesive surface between particles and the growth of sintering neck, which is conducive to the improvement of porous tungsten’s intensity.