Effects of chemistry and compact density on decomposition of PM lubricants

1994 ◽  
Vol 49 (11) ◽  
pp. 40
Keyword(s):  
Compact Density

Porous Al2O3/Al catalyst supports fabricated by an Al(OH)3/Al mixture and the effect of agglomerates

2005 ◽  
Vol 20 (3) ◽  
pp. 672-679 ◽  
Author(s):  
Zhen-Yan Deng ◽  
Yoshihisa Tanaka ◽  
Yoshio Sakka ◽  
Yutaka Kagawa
Keyword(s):  
Surface Area ◽  
Compaction Pressure ◽  
High Surface ◽  
High Surface Area ◽  
Catalyst Supports ◽  
Al Content ◽  
Starting Mixture ◽  
Mechanical And Electrical Properties ◽  
Uniform Microstructure ◽  
Compact Density

Porous Al2O3/Al catalyst supports were fabricated using a mixture of Al(OH)3 and Al powders, followed by pressureless sintering at a temperature of 600 °C in vacuum. Different pressures were used to prepare green compacts. High compaction pressure led to a high surface area and good mechanical and electrical properties for the sintered specimens. However, when the Al content in the sintered specimen exceeded a definite value, high compaction pressure decreased the surface area abruptly. Scanning electron microscopy observations revealed that agglomeration in the starting mixture has a significant effect on the microstructure of the sintered specimens. High compaction pressure greatly eliminated the agglomerates and led to a uniform microstructure for the sintered specimens. However, when the Al content in the starting mixture was too high, Al particles in the compacts prepared by the high pressure were largely sintered due to the high compact density so that most of the pores were closed. The present study indicates that a suitable compaction pressure is critical to obtaining superior Al2O3/Al supports.

Third-Harmonic Generation in Special Parabolic Quantum Wells

2013 ◽  
Vol 760-762 ◽  
pp. 392-396
Author(s):  
You Bin Yu
Keyword(s):  
Quantum Well ◽  
Density Matrix ◽  
Quantum Wells ◽  
Harmonic Generation ◽  
Third Harmonic Generation ◽  
Third Harmonic ◽  
The Third ◽  
Compact Density ◽  
Asymmetric Quantum ◽  
Parabolic Quantum Wells

Third-harmonic generation in a special asymmetric quantum well is investigated. The third-harmonic generation coefficient is carried out by applying compact-density-matrix method. The numerical results are presented for a GaAs/AlGaAs asymmetric quantum well. The very large third-harmonic generation coefficient is obtained in this quantum well. Moreover, the third-harmonic generation coefficient dependents on the quantum well parameters are investigated, respectively.

ELECTRO-OPTIC EFFECT IN A SEMI-PARABOLIC QUANTUM WELL WITH AN APPLIED ELECTRIC FIELD

2003 ◽  
Vol 17 (09) ◽  
pp. 347-354 ◽  
Author(s):  
LI ZHANG ◽  
HONG-JING XIE
Keyword(s):  
Electric Field ◽  
Quantum Well ◽  
Applied Electric Field ◽  
Field Effect ◽  
Harmonic Oscillation ◽  
Electric Field Effect ◽  
Confining Potential ◽  
Compact Density ◽  
Electro Optic ◽  
Potential Frequency

By using the compact density matrix approach, the electro-optic effect (EOE) in a semi-parabolic quantum well (QW) with an applied electric field has been theoretically investigated. Via a variant of displacement harmonic oscillation, the exact electronic states in the semi-parabolic QW with an applied electric field are obtained. Numerical results on typical GaAs material reveal that the electro-optic effect nearly linearly increases with the increasing of magnitude of the electric field, but it monotonously decreases with the increasing of confining potential frequency of the semi-parabolic QW. The EOE in the model investigated is 102 times larger than that in the symmetric parabolic QW under the same electric field and the same frequency of parabolic confining potential, which is due to the self-asymmetry of the system and the electric field effect.

Effect of compact density and preheating temperature of the Al–Ti–C preform on the fabrication of in situ Mg–TiC composites

2009 ◽  
Vol 45 (6) ◽  
pp. 1507-1513 ◽  
Author(s):  
A. K. Chaubey ◽  
B. K. Mishra ◽  
N. K. Mukhopadhyay ◽  
P. S. Mukherjee
Keyword(s):  
Compact Density ◽  
Preheating Temperature

ELECTRON–PHONON INTERACTION EFFECTS ON THIRD-HARMONIC GENERATION IN CYLINDRICAL QUANTUM WIRES

2004 ◽  
Vol 18 (01) ◽  
pp. 53-61 ◽  
Author(s):  
YOU-BIN YU ◽  
KANG-XIAN GUO
Keyword(s):  
Iterative Method ◽  
Harmonic Generation ◽  
Quantum Wires ◽  
Third Harmonic Generation ◽  
Matrix Approach ◽  
Phonon Interaction ◽  
Third Harmonic ◽  
Electron Phonon Interaction ◽  
The Third ◽  
Compact Density

The influence of electron–phonon interaction on third-harmonic generation in cylindrical quantum wires are investigated. The third-harmonic generation coefficient is obtained using compact-density-matrix approach and iterative method, and the numerical results are presented for GaAs cylindrical quantum wires. The results show that the third-harmonic generation coefficient is greatly enhanced after taking into consideration the influence of electron–phonon interaction. It is about thirty times larger than that obtained by just considering electron states when electron–phonon resonance is met.

High-resolution TEM and analytical study of second-phase particles in Al2O3

1983 ◽  
Vol 41 ◽  
pp. 46-47
Author(s):  
K. J. Morrissey ◽  
Y. Kouh ◽  
C. B. Carter
Keyword(s):  
Grain Size ◽  
High Resolution ◽  
Grain Boundaries ◽  
Hot Pressing ◽  
Analytical Study ◽  
Second Phase ◽  
Initial Powder ◽  
Compact Density ◽  
Second Phase Particles ◽  
High Resolution Tem

The influence of additives such as MgO, NiO, and ZrO2 and impurities such as Na, K, and Ca on the sintering of alumina compacts has been the focus of a considerable amount of research. Since these additives affect compact density and grain size it is of interest to determine the behavior of the elements during processing. That is, it is important to know whether Ca and Mg segregate to grain boundaries or are located in the second-phase particles. Current results suggest that Ca is found uniformly at the grain boundaries and that Mg is accommodated in the second-phase particles.The present investigation is concerned with identifying second-phase particles in different commercially-produced Al2O3 compacts and studying both their structure and composition. Preliminary results have been discussed previously. The investigation has dealt mainly with two different alumina compacts. One compact was prepared from an initial powder containing 0.25% MgO, a small amount of intentionally added Ni, and was prepared by hot pressing.

Sign in / Sign up

Export Citation Format

Share Document