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Online since: January 2005
Authors: Wan Qi Jie
The results showed that the
L
S S
S
L
L segregation in the radial direction was proportional to the solute Peclet number PeC, and the relative
depth of the concaved interface hr, except for the great influence of the solute partition ratio k [22],
where
L
C
D
RV
=Pe (3)
R
h
hr
∆
= (4)
R is the inner radius of the crucible, h∆ is the depth of the concaved interface, V is the growth rate
and DL is the diffusion coefficient of the solute in liquid phase
The method was first described by Capper et al [9-11], where three kinds of convections were identified i.e., spiral shearing flow, Ekman flow and Couette flow, depending on the Renolds number Re [27].
The Renold's number is given by γ ∆Ω = 2 Re R (5) where, R is the radius of the crucible, ∆Ω is the angular rate variation of the crucible rotation and γ is the kinematics viscosity of the melt.
In the process, the thermal field, solute redistribution, and forced convection interact each other and determine the crystal quality, such as the concentration homogeneities, grain sizes and the densities of different crystal defects, including point defects, dislocations and Te precipitates etc.
The method was first described by Capper et al [9-11], where three kinds of convections were identified i.e., spiral shearing flow, Ekman flow and Couette flow, depending on the Renolds number Re [27].
The Renold's number is given by γ ∆Ω = 2 Re R (5) where, R is the radius of the crucible, ∆Ω is the angular rate variation of the crucible rotation and γ is the kinematics viscosity of the melt.
In the process, the thermal field, solute redistribution, and forced convection interact each other and determine the crystal quality, such as the concentration homogeneities, grain sizes and the densities of different crystal defects, including point defects, dislocations and Te precipitates etc.
Online since: September 2011
Authors: Yu Hong Yang
After much research, has selected a number of high-temperature (optimal temperature up to 65 ℃), not sensitive to the concentration of the product (in 30% of the sugar solution can still continue to break down cellobiose), many excellent PH adapt to a wide range strains.
Degradation of crop stalks is a more complex biological degradation process, involved a number of chemical and biochemical reaction process, so the chemical analysis of degradation process explanation course detection naturally became a topic which was concerned by people working on biotechnology and analysis.
Currently a small number of microbes that break down plant polymers at the same time, such as white rot fungi, this kind of bacteria can produce the amount of 20%-25% degradation.
[2] Osborne B.G: n IRS Analysis of Grain Past, Present and Future.
Degradation of crop stalks is a more complex biological degradation process, involved a number of chemical and biochemical reaction process, so the chemical analysis of degradation process explanation course detection naturally became a topic which was concerned by people working on biotechnology and analysis.
Currently a small number of microbes that break down plant polymers at the same time, such as white rot fungi, this kind of bacteria can produce the amount of 20%-25% degradation.
[2] Osborne B.G: n IRS Analysis of Grain Past, Present and Future.
A Brief Review of Previous Studies on Regularity of Stress Waves Propagation in Micro-Cracks of Rock
Online since: May 2012
Authors: Jin Yu, Yan Yan Cai, Bo Xue Song, Xu Chen
Two independent complex moduli are required for isotropic material, and the number of complex moduli increases with the degree of anisotropy (e.g., five complex moduli are required for transversely isotropic medium).
It is because that the attenuation coefficient caused by fluid viscosity is proportional to frequency, and the attenuation coefficient caused by scattering is proportional to crack density (crack density is defined as the product of the number density of cracks and the third power of the average crack radius) and to the fourth power of frequency.
His studies revealed that wave attenuation caused by scattering is not only related to frequency, but also proportional to crack density (crack density is defined as the product of the number density of cracks and the third power of the average crack radius) and to the third power of ratio of mean crack radius to incident wavelength.
Murphy [19-21] interpreted wave attenuation in his experiment in terms of frictional sliding at grain boundaries and crack faces.
It is because that the attenuation coefficient caused by fluid viscosity is proportional to frequency, and the attenuation coefficient caused by scattering is proportional to crack density (crack density is defined as the product of the number density of cracks and the third power of the average crack radius) and to the fourth power of frequency.
His studies revealed that wave attenuation caused by scattering is not only related to frequency, but also proportional to crack density (crack density is defined as the product of the number density of cracks and the third power of the average crack radius) and to the third power of ratio of mean crack radius to incident wavelength.
Murphy [19-21] interpreted wave attenuation in his experiment in terms of frictional sliding at grain boundaries and crack faces.
Online since: April 2009
Authors: Paul Heitjans, Martin Wilkening, W. Iwaniak, J. Fritzsche, M. Zukalová, R. Winter
The mechanically treated samples are characterized by a large number fraction
of interfacial regions which often provide fast diffusion pathways for the ions.
In fact, in the spinel structure of Li4Ti5O12 the Ti4+ cations are randomly distributed over the 16d positions leading, according to quantum chemical calculations of the EFGs [17], to a large number of electrically different Li sites.
However, high-energy ball milling of microcrystalline Li4Ti5O12 for 2 h in a SPEX shaker mill leads to a highly defective material with a large number of interfacial regions and grain boundaries.
In fact, in the spinel structure of Li4Ti5O12 the Ti4+ cations are randomly distributed over the 16d positions leading, according to quantum chemical calculations of the EFGs [17], to a large number of electrically different Li sites.
However, high-energy ball milling of microcrystalline Li4Ti5O12 for 2 h in a SPEX shaker mill leads to a highly defective material with a large number of interfacial regions and grain boundaries.
Online since: August 2004
Authors: Tae Won Kim
Over the past years
a number of MMCs have been developed, and among those titanium matrix composites are increasingly
attractive for a range of applications due to their high strength, stiffness, and creep resistance especially at high
temperatures [2,3].
After consolidation, the specimen allowed to furnace cool, and then usual post processing has been performed for the quantification of microstructural features such as the volume fraction of porosity and grain size.
During the thermal cycle, numbers of the AE event-counts, amplitude, and energy were measured.
As densification proceeds, the remaining porosities are expected to be removed, and thus the number of thermo-AE event-counts corresponds to the amount of porosity distributions reserved.
After consolidation, the specimen allowed to furnace cool, and then usual post processing has been performed for the quantification of microstructural features such as the volume fraction of porosity and grain size.
During the thermal cycle, numbers of the AE event-counts, amplitude, and energy were measured.
As densification proceeds, the remaining porosities are expected to be removed, and thus the number of thermo-AE event-counts corresponds to the amount of porosity distributions reserved.
Online since: January 2010
Authors: Yan He, Yang Lv, Lu Han
From the SEM photograph of the sample shown as fig 6, the mesoporous molecular sieve
samples were reunited products particles and the crystal grain are uniformly distributed.
Fig 5 TEM Photo of the samples Fig 6 SEM photo of the samples Fig 7 shows the IR pattern of the samples, the 1150 cm wave number was assigned to the unsymmetrical stretch mode of the Si-O-Si bond and the 620 cm wave number was assigned to the chain vibration of the Si-O-Si bond.
Besides, the 1225cm wave number was the dominant peak of the mesoporous molecular sieve MCM-41.
Fig 5 TEM Photo of the samples Fig 6 SEM photo of the samples Fig 7 shows the IR pattern of the samples, the 1150 cm wave number was assigned to the unsymmetrical stretch mode of the Si-O-Si bond and the 620 cm wave number was assigned to the chain vibration of the Si-O-Si bond.
Besides, the 1225cm wave number was the dominant peak of the mesoporous molecular sieve MCM-41.
Online since: March 2007
Authors: S.T. Davies
Whether or not the energy distribution at the substrate corresponds to that at the target depends on
the number of collisions between target and substrate and hence on the mean free path λ of the
sputtered species in argon.
This is evaluated from λ = 1/(√2πN(rAr+rS)2)) where N is the number of argon ions m -3 , rAr is the atomic radius of Ar and rS is the atomic radius of a sputtered atom. λ is around 120 cm for Ti and 140 cm for Ni at 0.05 mtorr.
As expected, the volume ablated increases with number of laser pulse shots and with fluence; however, other effects related to size of ablated features and crystallographic grain size can play significant roles[9].
This is evaluated from λ = 1/(√2πN(rAr+rS)2)) where N is the number of argon ions m -3 , rAr is the atomic radius of Ar and rS is the atomic radius of a sputtered atom. λ is around 120 cm for Ti and 140 cm for Ni at 0.05 mtorr.
As expected, the volume ablated increases with number of laser pulse shots and with fluence; however, other effects related to size of ablated features and crystallographic grain size can play significant roles[9].
Online since: June 2010
Authors: Bing Yang, Yong Xiang Zhao
Brittleness and grain interface fracture of high Cr and
Cr-Mo cast steels can be controlled by moderate contents of aluminum and nitrogen elements plus
sustaining temperature out of 900~1200℃ range[6].
Similar to the measurements for scattered S-� data [17], a probabilistic modeling for considering the scattered test Aeff-�s data under �s following lognormal distribution as effavavavs, lg lg ATQ� += ; effrms rms rmss, lg lg ATQ� += ; eff s, lg lg ATQ� CPCPCP −− − += (2) ( ) [ ] rmso1 av 1 QntZQQ CP CP −+−= −− ; ( ) [ ] rmso1 av 1 TntZTT CP CP −+−= −− (3) where ZP is the percentage of the standard normal distribution at a probability of P; t1-C(no-2) is the t-distribution function at a significance of 1-C with degree-of-freedom of no-2 and no is number of paired test Aeffi-�i data for material specimens, where i is group ordinal of the specimens equal to 1, 2, …, ns and ns is number of graded groups of the specimens; Qav、Tav、Qrms and Trms are material constants, which should be evaluated using the former two terms of Eq. (2) to fit into lgAeffi-lg�s,avi data and lgAeffi-lg�s,rmsi data, respectively.
Considering the difference of specimen numbers between different groups, equivalent data lg�s,avi and lg�s,rmsi at lgAeffi are estimated by equations ∑== in j ij i � � 1 av lg lg , ( ) ( ) ( ) 5.0 1 av o1 1 rms lglg 1 1 1 1 lg − −− − = ∑= − − in j i ij i C iC i �� nnt nt � (4) where ij represents specimen ordinal j at group i.
Similar to the measurements for scattered S-� data [17], a probabilistic modeling for considering the scattered test Aeff-�s data under �s following lognormal distribution as effavavavs, lg lg ATQ� += ; effrms rms rmss, lg lg ATQ� += ; eff s, lg lg ATQ� CPCPCP −− − += (2) ( ) [ ] rmso1 av 1 QntZQQ CP CP −+−= −− ; ( ) [ ] rmso1 av 1 TntZTT CP CP −+−= −− (3) where ZP is the percentage of the standard normal distribution at a probability of P; t1-C(no-2) is the t-distribution function at a significance of 1-C with degree-of-freedom of no-2 and no is number of paired test Aeffi-�i data for material specimens, where i is group ordinal of the specimens equal to 1, 2, …, ns and ns is number of graded groups of the specimens; Qav、Tav、Qrms and Trms are material constants, which should be evaluated using the former two terms of Eq. (2) to fit into lgAeffi-lg�s,avi data and lgAeffi-lg�s,rmsi data, respectively.
Considering the difference of specimen numbers between different groups, equivalent data lg�s,avi and lg�s,rmsi at lgAeffi are estimated by equations ∑== in j ij i � � 1 av lg lg , ( ) ( ) ( ) 5.0 1 av o1 1 rms lglg 1 1 1 1 lg − −− − = ∑= − − in j i ij i C iC i �� nnt nt � (4) where ij represents specimen ordinal j at group i.
Online since: March 2004
Authors: Jun Akedo
Experimental parameters
Pressure in deposition chamber 0.05 ~ 0.3 kPa
Pressure in aerosol chamber 10 ~ 80 kPa
Size of nozzle orifice 5 x 0.3 mm
2
; 10 x0.4 mm
2
Accelerating gas He, N2, air,
Consumption of accelerating gas 1 ~ 10 l/min
Maintained substrate temperature during deposition 300 K
Scanning area (area of deposition) up to 40 x 40 mm
2
Scanning speed of the nozzle motion along substrate 0.125 ~ 10 mm/sec
Distance between the nozzle and substrate 1 mm~ 40 mm
Journal Title and Volume Number (to be inserted by the publisher)
200-800 nm.
On the other hand, after the heat treatment procedure of the starting powder to growth particle grain size, density and transmittance of the layer significantly recovered as shown in Fig. 4[4, 5].
Impact particles velocity Discussion of deposition mechanism Journal Title and Volume Number (to be inserted by the publisher) From previous studies, deposition results strongly depend on particles diameter and velocity [1,5].
Si mirror PZT� thick layer for monmorpgh actuator Journal Title and Volume Number (to be inserted by the publisher) [2] J.
On the other hand, after the heat treatment procedure of the starting powder to growth particle grain size, density and transmittance of the layer significantly recovered as shown in Fig. 4[4, 5].
Impact particles velocity Discussion of deposition mechanism Journal Title and Volume Number (to be inserted by the publisher) From previous studies, deposition results strongly depend on particles diameter and velocity [1,5].
Si mirror PZT� thick layer for monmorpgh actuator Journal Title and Volume Number (to be inserted by the publisher) [2] J.
Online since: March 2014
Authors: Johannes Dallmeier, Holger Saage, Otto Huber
In [9] the determination of hysteresis energy density ∆W and the evolution of ∆W in dependence on the number of cycles is described and in [6], the plastic hysteresis energy density ∆Wpl as a function of the strain amplitude εa at strain controlled pure reversal tests (Rε=-1) is given.
The sheets show a homogeneous microstructure with an average grain size of 4.8µm (in rolling direction RD as well as in transverse direction TD) and a strong basal texture [11].
Fig. 2: a) Representative hysteresis loop at half number of cycles to failure Nf with corresponding hysteresis energy densities (plastic hysteresis energy density ∆Wpl, elastic hysteresis energy density ∆Wel, pseudoelastic hysteresis energy density ∆Wpsel); b) weighting factor F∆Wpl as a function of stress ratio R.
The authors acknowledge the financial support of the Federal Ministry of Education and Research (BMBF) within the funding program FHprofUnt in the project “MagFest” under the contract number 03FH015PX2.
The sheets show a homogeneous microstructure with an average grain size of 4.8µm (in rolling direction RD as well as in transverse direction TD) and a strong basal texture [11].
Fig. 2: a) Representative hysteresis loop at half number of cycles to failure Nf with corresponding hysteresis energy densities (plastic hysteresis energy density ∆Wpl, elastic hysteresis energy density ∆Wel, pseudoelastic hysteresis energy density ∆Wpsel); b) weighting factor F∆Wpl as a function of stress ratio R.
The authors acknowledge the financial support of the Federal Ministry of Education and Research (BMBF) within the funding program FHprofUnt in the project “MagFest” under the contract number 03FH015PX2.