Theoretical Prediction of the Stability and Intramolecular Rearrangement Reactions of Heteroanalogues of Cyclopropylcarbene:  2-Oxiranyl-, 2-Aziridinyl-, and 1-Aziridinylcarbene

2000 ◽  
Vol 65 (5) ◽  
pp. 1366-1375 ◽  
Author(s):  
Christian Mück-Lichtenfeld
Keyword(s):  
Theoretical Prediction ◽  
Intramolecular Rearrangement ◽  
Rearrangement Reactions ◽  
The Stability

Umlagerungsreaktionen von lithiierten Silylhydroxylaminen mit Fluorsilanen / Rearrangement Reactions of Lithiated Silylhydroxylamines with Fluorosilanes

1981 ◽  
Vol 36 (11) ◽  
pp. 1356-1360 ◽  
Author(s):  
Dieter Bentmann ◽  
Uwe Klingebiel
Keyword(s):  
Intramolecular Rearrangement ◽  
Analogous Reaction ◽  
Rearrangement Reactions

Abstract Halogenosilanes, with the exception of CH3SiF3 and SiF4, react with lithiated bis-(trimethylsilyl)hydroxylamine in ether to yield substituted hydroxylamines, and LiF. In the analogous reaction with trifluoromethylsilane and tetrafluorosilane the products undergo an intramolecular rearrangement to form silylaminosiloxanes.

THE STAEILITY OF COUETTE FLOW IN AN AXIAL MAGNETIC FIELD

1958 ◽  
Vol 36 (11) ◽  
pp. 1509-1525 ◽  
Author(s):  
E. R. Niblett
Keyword(s):  
Magnetic Field ◽  
Boundary Conditions ◽  
Theoretical Prediction ◽  
Viscous Flow ◽  
Rotation Speed ◽  
Axial Magnetic Field ◽  
Radioactive Isotopes ◽  
Electrically Conducting ◽  
Electrically Conducting Fluid ◽  
The Stability

Chandrasekhar's theory of the stability of viscous flow of an electrically conducting fluid between coaxial rotating cylinders with perfectly conducting walls is extended to include the case of non-conducting walls, and it is found that their effect is to reduce the critical Taylor numbers and increase the wavelength of the instability patterns by considerable amounts. An experiment designed to measure the values of magnetic field and rotation speed at the onset of instability in mercury between perspex cylinders is described. The radioactive isotopes Hg197 and Hg203 were used to trace the flow. The results support the theoretical prediction that the boundary conditions can have a large effect on the motion.

Spontaneous Formation and Stability of GaP Cage Structures: A Theoretical Prediction of a New Fullerene

2001 ◽  
Vol 675 ◽  
Author(s):  
Francesco Buda ◽  
Valentina Tozzini ◽  
Annalisa Fasolino
Keyword(s):  
Molecular Dynamics ◽  
Theoretical Prediction ◽  
Ab Initio Molecular Dynamics ◽  
Fullerene Cage ◽  
Spontaneous Formation ◽  
Energy Gaps ◽  
Bulk Structure ◽  
The Stability ◽  
Dynamics Simulations ◽  
Geometric And Electronic Properties

ABSTRACTWe report the spontaneous formation of a GaP fullerene cage in ab-initio Molecular Dynamics simulations starting from a bulk fragment. A systematic study of the geometric and electronic properties of neutral and ionized III-V (GaP, GaAs, AlAs, AIP) clusters suggests the stability of hetero-fullerenes formed by compounds with zincblend bulk structure. Our prediction is supported by several indicators: these clusters show closed electronic shells and relatively large energy gaps; the ratio between the cohesive energy per atom in the cluster and in the bulk is very close to the value found for carbon fullerenes of the same size; the clusters are thermally stable up to a temperature range of 1500–2000 K and they do not dissociate when ionized.

scholarly journals Snapping of a Planar Elastica With Fixed End Slopes

2008 ◽  
Vol 75 (4) ◽  
Author(s):  
Jen-San Chen ◽  
Yong-Zhi Lin
Keyword(s):  
Theoretical Prediction ◽  
Static Load ◽  
Natural Frequencies ◽  
Equilibrium Configuration ◽  
The Other ◽  
Deflection Curve ◽  
Slope Difference ◽  
The Stability ◽  
Fixed End ◽  
Load Deflection Curve

In this paper, we study the deformation and stability of a planar elastica. One end of the elastica is clamped and fixed in space. The other end of the elastica is also clamped, but the clamp itself is allowed to slide along a linear track with a slope different from that of the fixed clamp. The elastica deforms after it is subjected to an external pushing force on the moving clamp. It is observed that when the pushing force reaches a critical value, snapping may occur as the elastica jumps from one configuration to another remotely away from the original one. In the theoretical investigation, we calculate the static load-deflection curve for a specified slope difference between the fixed clamp and the moving clamp. To study the stability of the equilibrium configuration, we superpose the equilibrium configuration with a small perturbation and calculate the natural frequencies of the deformed elastica. An experimental setup is designed to measure the load-deflection curve and the natural frequencies of the elastica. The measured load-deflection relation agrees with the theoretical prediction very well. On the other hand, the measured natural frequencies do not agree very well with the theoretical prediction, unless the mass of the moving clamp is taken into account.

THEORETICAL PREDICTION OF EXTREMELY NEUTRON RICH Zr AND Pb

2010 ◽  
Vol 19 (03) ◽  
pp. 449-457 ◽  
Author(s):  
K. A. GRIDNEV ◽  
V. N. TARASOV ◽  
D. V. TARASOV ◽  
D. K. GRIDNEV ◽  
V. V. PILIPENKO ◽  
...  
Keyword(s):  
Theoretical Prediction ◽  
Ground State ◽  
Neutron Emission ◽  
Pb Isotopes ◽  
Neutron Density ◽  
Unstable Nucleus ◽  
Hartree Fock ◽  
Density Distributions ◽  
Deformation Parameters ◽  
The Stability

The properties of even–even Zr and Pb isotopes in the ground state are studied up to the neutron drip-lines on the basis of the Hartree–Fock method with Skyrme forces allowing for deformation (DHF). The DHF calculations with Ska forces predict the existence of stability peninsula (or island) around 152 Zr . On the example of Zr isotopes it is shown that adding neutrons to an already unstable nucleus with neutron excess can restore the stability. It is demonstrated that extremely neutron-rich Pb isotopes for 222≤A≤230 have abnormally large deformation parameters of proton and neutron density distributions. The existence of 266–288 Pb stable against one-neutron emission is also predicted.

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