scholarly journals Growth Condition Dependence Of Rheed Pattern From GaAs (111)B Surface

1991 ◽  
Vol 228 ◽  
Author(s):  
K. Yang ◽  
W. Li ◽  
A. P. Taylor ◽  
Q.-F. Xiao ◽  
L. J. Schowalter ◽  
...  
Keyword(s):  
Experimental Data ◽  
Phase Diagram ◽  
Growth Conditions ◽  
Condition Dependence ◽  
Rheed Pattern ◽  
3 Dimensional ◽  
Ion Channeling ◽  
Surface Reconstructions ◽  
Substrate Temperatures ◽  
Rough Surface Morphology

ABSTRACTA 3-dimensional phase diagram is introduced to describe the dependence of the RHEED pattern from GaAs(111)B surface on growth conditions. The 2×2, transitional(1×1), and √19×,√19 surface reconstructions correspond to different zones in the phase diagram. A equation is given for the planes that separate these zones, which fit experimental data well. Homoepitaxial films on GaAs(111)B grown in the 2×2 region generally have bad crystal quality as determined by the ion channeling, and growth in the √19×√19 region generally yields rough surface morphology. At higher substrate temperatures (∼ 650 °C), featureless films with minimum ion channeling yields of less than 4% are achieved.

scholarly journals Thermodynamic reassessment of the Mn-Ni-Si system

2015 ◽  
Vol 51 (2) ◽  
pp. 125-132 ◽  
Author(s):  
B. Hu ◽  
Y. Du ◽  
J.J. Yuan ◽  
Z.F. Liu ◽  
Q.P. Wang
Keyword(s):  
Experimental Data ◽  
Phase Diagram ◽  
Phase Diagrams ◽  
Thermodynamic Parameters ◽  
Ternary Phase ◽  
Sublattice Model ◽  
Diagram Approach ◽  
Measured Phase

Iased on the new experimental data available in the literature, the Mn-Ni-Si system has been reassessed using the CALPHAD (CALculation of PHAse Diagram) approach. Compared with the previous modeling, the ?8 and ?12 ternary phases were treated as the same phase according to the new experimental data. The Mn3Si phase was described with two sublattice model (Mn, Ni)3(Si)1. The reported new ternary phase ? was not considered in the present work. Comprehensive comparisons between the calculated and measured phase diagrams showed that a set of thermodynamic parameters of the Mn-Ni-Si system obtained in this work was more accurate than the previous one.

Stiffness Degradation of Digital Polypropylene Under Fatigue Loading: Investigations via 3-Dimensional Polyjet Printed Coupons

2020 ◽  
Author(s):  
Ravi Pratap Singh Tomar ◽  
Furkan I. Ulu ◽  
Ajit Kelkar ◽  
Ram V. Mohan
Keyword(s):  
Experimental Data ◽  
Regression Analysis ◽  
Fatigue Life ◽  
Cyclic Loading ◽  
Fatigue Loading ◽  
Stiffness Degradation ◽  
Damage State ◽  
3 Dimensional ◽  
Accumulated Damage ◽  
Polyjet Printing

Abstract The utilization of additively manufactured parts is gaining popularity in functional applications. Polymer-based additive manufacturing (AM) parts are utilized in a variety of engineering applications for automotive, aerospace, and energy. AM printed parts are however newer class of materials, and structural performance of these materials is not fully understood completely, and very limited exists currently on precisely performance of Polyjet printed parts and associated digital materials under fatigue loading. This paper investigates the stiffness degradation under tension-tension fatigue loading of digital polypropylene using homogenous 3-Dimensional test coupons formed using PolyJet printing. Homogeneous 3-Dimensional test configuration employed in the present study eliminates the process-induced limitations of traditional ASTM D638 2D fatigue test coupons for AM processed materials. Fatigue data is analyzed to present an empirical model of effective elastic modulus and an analytical model of the accumulated damage state, as defined on the basis of stiffness degradation during cyclic loading. Further, the actual damage accumulation due to cyclic loading with the predicted model is compared. Modeling of the S-N diagram provides a better estimation of fatigue life and fatigue life modeling of AM printed test coupons and is obtained via linear regression analysis of experimental data with high correlation coefficient R2 (0.9971). The analytical model of the accumulated damage state is based on the stiffness degradation and is derived from the regression analysis of experimental data of stiffness degradation at different loading percentages assuming a polynomial of degree 4. Present study provides insight into the fatigue damage state and cyclic performance of digital polypropylene from Polyjet printing.

Surface-Sensitive Microwear Texture Analysis of Attrition and Erosion

2016 ◽  
Vol 96 (3) ◽  
pp. 300-307 ◽  
Author(s):  
S. Ranjitkar ◽  
A. Turan ◽  
C. Mann ◽  
G.A. Gully ◽  
M. Marsman ◽  
...  
Keyword(s):  
Clinical Practice ◽  
Evolutionary Biology ◽  
Optical Resolution ◽  
Tooth Wear ◽  
Tissue Type ◽  
Human Teeth ◽  
Posterior Teeth ◽  
3 Dimensional ◽  
Surface Reconstructions ◽  
Posterior Group

Scale-sensitive fractal analysis of high-resolution 3-dimensional surface reconstructions of wear patterns has advanced our knowledge in evolutionary biology, and has opened up opportunities for translatory applications in clinical practice. To elucidate the microwear characteristics of attrition and erosion in worn natural teeth, we scanned 50 extracted human teeth using a confocal profiler at a high optical resolution (X–Y, 0.17 µm; Z < 3 nm). Our hypothesis was that microwear complexity would be greater in erosion and that anisotropy would be greater in attrition. The teeth were divided into 4 groups, including 2 wear types (attrition and erosion) and 2 locations (anterior and posterior teeth; n = 12 for each anterior group, n = 13 for each posterior group) for 2 tissue types (enamel and dentine). The raw 3-dimensional data cloud was subjected to a newly developed rigorous standardization technique to reduce interscanner variability as well as to filter anomalous scanning data. Linear mixed effects (regression) analyses conducted separately for the dependent variables, complexity and anisotropy, showed the following effects of the independent variables: significant interactions between wear type and tissue type ( P = 0.0157 and P = 0.0003, respectively) and significant effects of location ( P < 0.0001 and P = 0.0035, respectively). There were significant associations between complexity and anisotropy when the dependent variable was either complexity ( P = 0.0003) or anisotropy ( P = 0.0014). Our findings of greater complexity in erosion and greater anisotropy in attrition confirm our hypothesis. The greatest geometric means were noted in dentine erosion for complexity and dentine attrition for anisotropy. Dentine also exhibited microwear characteristics that were more consistent with wear types than enamel. Overall, our findings could complement macrowear assessment in dental clinical practice and research and could assist in the early detection and management of pathologic tooth wear.

Epitaxial Iridium Growth on Strontium Titanate

2000 ◽  
Vol 648 ◽  
Author(s):  
Z. Dai ◽  
A.P. Li ◽  
C. Bednarski ◽  
L. I. McCann ◽  
B. Golding
Keyword(s):  
Surface Roughness ◽  
Substrate Surface ◽  
Surface Preparation ◽  
Electron Beam Evaporation ◽  
Layer By Layer ◽  
Epitaxial Relationship ◽  
Ion Channeling ◽  
Substrate Temperatures ◽  
Subsequent Layer

AbstractEpitaxial (100) iridium films have been grown on (100) SrTiO3 (STO) substrates by electron beam evaporation. The epitaxial relationship between the iridium film and STO substrate was determined to be Ir(001)[100]//STO(001)[100]. A systematic study of the role of STO substrate surface preparation, Ir thickness, and substrate temperature on Ir film crystallinity and morpholo- gy has been performed. The best Ir films typically have small Ir(200) XRD linewidths < 0.3 °, surface roughness of 0.2 nm, and low ion channeling yields, χmin≤ 4%, when deposited at 800 °C. Films generally become smoother with better crystallinity when the film thickness approaches 300 nm. A growth mode with initial island formation and subsequent layer-by-layer appears to take place at higher substrate temperatures, whereas at lower temperatures the film grows in a 3D mode.

Cold-Set Whey Protein Isolate Gels Prepared with Mg2+: Denaturing Conditions and Phase Diagram

2009 ◽  
Vol 283-286 ◽  
pp. 559-564 ◽  
Author(s):  
M. Vázquez da Silva ◽  
João M.P.Q. Delgado
Keyword(s):  
Experimental Data ◽  
Phase Diagram ◽  
Young’S Modulus ◽  
Whey Protein ◽  
Elastic Properties ◽  
Magnesium Chloride ◽  
Whey Protein Isolate ◽  
Protein Isolate ◽  
Viscoelastic Behaviour ◽  
Made In

Cold-set gels of whey protein isolate (WPI) were produced. The cold gelation was induced through the addition of magnesium chloride whose cation is an alternative to the most common cations used in this kind of gelation. A phase diagram for denatured WPI in magnesium was determined by varying protein and salt concentrations. In this diagram the protein and cation concentrations varied from 0.3 to 8.0 wt % and 1 to 75 mM, respectively. The viscoelastic behaviour of the WPI was analysed, whereas gels elastic properties were measured by means of texture tests. Mathematical manipulation of the experimental data relative to the puncture tests was made in order to obtain the Young’s modulus for each cold-set gel.

SELF-ASSEMBLED Ge-DOTS FOR Si SOLAR CELLS

2002 ◽  
Vol 16 (28n29) ◽  
pp. 4347-4351 ◽  
Author(s):  
H. PRESTING ◽  
J. KONLE ◽  
H. KIBBEL
Keyword(s):  
Solar Cells ◽  
Open Circuit Voltage ◽  
Elevated Temperatures ◽  
Growth Conditions ◽  
Open Circuit ◽  
3 Dimensional ◽  
Force Microscopy ◽  
Atomic Force ◽  
Transmission Electron ◽  
P Type

Silicon solar cells with embedded germanium (Ge) layers deposited as 3-dimensional islands in the Stranski-Krastanov growth mode have been grown by molecular beam epitaxy (MBE) to enhance the efficiency of Si thin film solar cells. The Ge-layers increase the infrared absorption in the base of the cell to achieve higher photocurrent which should overcome the loss in the open circuit voltage due to incorporation of a smaller bandgap material in the heterostructure. Up to 75 layers of Ge, each about 8 monolayers (ML) thick, separated by Si-spacer layers (9-18nm) have been deposited at rather elevated temperatures (700°C) on a standard 10Ωcm p-type Si-substrate. Island densities of 1011 cm -2 have been achieved by use of antimony (Sb) as surfactant. Atomic force microscopy (AFM) and transmission electron microscopy (TEM) were used to characterize the growth of Ge-islands under variuos growth conditions. Photocurrent measurements exhibit a higher photo-response in the infrared regime but a lower open circuit voltage of the fabricated solar cells compared to a Si-reference cell.

Phase Diagram and Research for the Ternary System of NaCl-CsCl-H2O at 50°C

2013 ◽  
Vol 706-708 ◽  
pp. 193-196 ◽  
Author(s):  
Yong Ming Zhang ◽  
Li Chun Ma ◽  
Cheng Lin Liu ◽  
Li Fang Chen ◽  
Dong Liang Shen ◽  
...  
Keyword(s):  
Experimental Data ◽  
Phase Diagram ◽  
Ternary System ◽  
Invariant Point ◽  
Equilibrium Phase ◽  
Ternary Systems ◽  
Practical Significance ◽  
Eutectic Type ◽  
Comprehensive Utilization ◽  
Isothermal Evaporation

The equilibria phase of the ternary systems NaCl-CsCl-H2O was studied at 50°C by the isothermal evaporation method. The equilibrium phase diagrams were plotted in line with the experimental data. It suggest that the phase diagram of NaCl-CsCl-H2O is the simple eutectic type where one invariant point is found to have the compositions of 12.3% NaCl, 54.1% CsCl and 33.6% H2O by mass, respectively. The study provide fundamental thermodynamic data of brine system that contains sodium and cesium, and has practical significance for the brine’s comprehensive utilization.

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