Further research on the good lattice point design

In many inclusion–host systems with similar oxygen packing schemes, the optimum crystallographic orientation relationship (COR) between the inclusion and the host is mostly determined by matching the similar oxygen sublattices of the two structures. In contrast, the prediction of the optimum COR or even just the rationalization of the observed COR(s) between an inclusion and host with incompatible oxygen sublattices, like rutile–garnet, is not straightforward. The related documentation for such cases is therefore limited. Given the abundant crystallographic data for the rutile–garnet system acquired by transmission electron microscopy and electron backscatter diffraction methods recently, this problem can now be examined in detail for the critical structural factors dictating the selection of optimum COR in such a structurally complicated system. On the basis of the unconstrained three-dimensional lattice point match and structural polyhedron match calculated for the observed CORs, it becomes clear that the prerequisite of optimum COR for rutile (rt) in garnet (grt) is to have most of their octahedra similarly oriented/inclined in space by aligning 〈103〉rtand 〈111〉grtfor needle extension growth. Further rotation along the 〈103〉rt//〈111〉grtdirection then leads to the energetically most favorable COR-2 variant with a good lattice point match defined by the coincidence site lattice (CSL) and a good topotaxial match of the constituent polyhedra at the CSL points, leaving unfavorable COR-1′ in the forbidden zones. This understanding sheds light not only on hierarchical energetics for the selection of inclusion variants in a complicated inclusion–host system, but also on yet-to-be-explored [UVW]-specific CORs and hetero-tilt boundaries for composite materials in general.

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Method for Estimating Failure Probability of Mechanical Structures Using Number Theoretical Net (NT-net) Simulation

Materials Science Forum ◽

10.4028/www.scientific.net/msf.628-629.239 ◽

2009 ◽

Vol 628-629 ◽

pp. 239-244

Author(s):

Z.J. Wen ◽

De Shun Liu ◽

Shu Yi Yang

Keyword(s):

Failure Probability ◽

Simulation Method ◽

Computational Effort ◽

Side Impact ◽

Computational Accuracy ◽

Simulation Techniques ◽

Net Method ◽

Good Lattice ◽

Good Lattice Point ◽

Point Set

According to poor computational accuracy at small to median sample sizes of Monte Carlo ( MC ) simulation techniques in estimating the probability failure of mechanical structures, the number theoretical net ( NT-net ) simulation method is proposed to reduce computing effort. Several key concepts, such as good point set, good-lattice point ( glp ), discrepancy and NT-net method, are defined. The sampling stategy is improved by introducing NT-net that can provide better convergent rate over MC. The new method is used to estimate failure probability of the side impact bar on the car door. Results indicate the computational effort needed by NT-net for the same accuracy is about 1/12 of that needed by the MC-based method, and the obtained results are more stable.

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Evaluation Method and Application of Assembly Yield in Two-Dimension Multi-Station Assembly Processes Based on Number-Theoretical Net

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.522.921 ◽

2012 ◽

Vol 522 ◽

pp. 921-926

Author(s):

Ze Jun Wen ◽

Zheng Qiang Zhu ◽

Yan Ming Zhao ◽

Fan Zhang

Keyword(s):

Evaluation Method ◽

State Space Model ◽

Total Sample ◽

Two Dimension ◽

Automotive Body ◽

Variation Propagation ◽

Net Method ◽

Good Lattice ◽

Good Lattice Point ◽

Component Assembly

Method for calculating assembly yield in two-dimension multi-station assembly processes is developed based on Number-Theoretical Net (NT-net). The discrepancy of NT-net is analyzed, and the principle of generating good lattice point (glp) based on NT-net method is introducted. Afterwards, taking fixture locating variations which are sampled using NT-net method for input vectors, the samples are substituted into state space model of dimension variation propagation in multi-station assembly processes to get output vectors. The statistics for qualified sample is accomplished, after comparing output vectors with the variations of measuring points on component. Assembly yield in two-dimension multi-station assembly processes is gained when qualified sample divided by total sample. Finally, a real case in automotive body floor assembly is given as an example to calculate the assembly yield in two-dimension three-station assembly processes. The result is validated by using Monte carlo simulation. It provides a new way to predict assembly yield in two-dimension multi-station assembly processes.

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Electron microscope characterization of MOCVD-grown gap layers on Si

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100144991 ◽

1986 ◽

Vol 44 ◽

pp. 724-725

Author(s):

K.M. Jones ◽

M.M. Al-Jassim ◽

J.M. Olson

Keyword(s):

Atmospheric Pressure ◽

Vapour Deposition ◽

Chemical Vapour ◽

Organic Chemical ◽

Lattice Match ◽

Si Substrates ◽

Metal Organic ◽

Good Lattice ◽

Antiphase Domains

The epitaxial growth of III-V semiconductors on Si for integrated optoelectronic applications is currently of great interest. GaP, with a lattice constant close to that of Si, is an attractive buffer between Si and, for example, GaAsP. In spite of the good lattice match, the growth of device quality GaP on Si is not without difficulty. The formation of antiphase domains, the difficulty in cleaning the Si substrates prior to growth, and the poor layer morphology are some of the problems encountered. In this work, the structural perfection of GaP layers was investigated as a function of several process variables including growth rate and temperature, and Si substrate orientation. The GaP layers were grown in an atmospheric pressure metal organic chemical vapour deposition (MOCVD) system using trimethylgallium and phosphine in H2. The Si substrates orientations used were (100), 2° off (100) towards (110), (111) and (211).

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A New Condition of Formation and Stablity of All Crystalline Systems in a Good Agreement with Experimental Data

JOURNAL OF ADVANCES IN PHYSICS ◽

10.24297/jap.v11i3.6942 ◽

2015 ◽

Vol 11 (3) ◽

pp. 3224-3228

Author(s):

Tarek El-Ashram

Keyword(s):

Experimental Data ◽

Brillouin Zone ◽

Electron Concentration ◽

Free Electron ◽

Lattice Point ◽

Valence Electron ◽

Fermi Gas ◽

Valence Electron Concentration ◽

Fermi Sphere ◽

Good Agreement

In this paper we derived a new condition of formation and stability of all crystalline systems and we checked its validity andit is found to be in a good agreement with experimental data. This condition is derived directly from the quantum conditionson the free electron Fermi gas inside the crystal. The new condition relates both the volume of Fermi sphere VF andvolume of Brillouin zone VB by the valence electron concentration VEC as ;ð‘½ð‘ð‘½ð‘©= ð’ð‘½ð‘¬ð‘ªðŸfor all crystalline systems (wheren is the number of atoms per lattice point).

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