the conformational behavior of monosubstituted tri-methylsilyle ethynyl derivative of cal ix[4]arene as a newgeneration of caliarene was compared with tetra alkylated calyx[4]arene. the most important conformationalphenomena in these compounds which are pinched cone interconversion process were done by semi-empiricalmethod and ab initio calculations with gaussian 98w programming.

In this paper we prove that the coordinate ring of the pinched Veronese (i.e k[X, XY, XY , Y , XZ, Y Z, XZ, Y Z, Z] ⊂ k[X, Y, Z]) is Koszul. The strategy of the proof is the following: we can consider a presentation S/I where S = k[X1, . . . , X9]. Using a distinguished weight ω, it’s enough to show that S/inωI is Koszul. We write inωI as J + H where J is generated by a Gröbner basis of quadric...

In this paper, we study closed four-dimensional manifolds. particular, show that under various new pinching curvature conditions (for example, the sectional is no more than 5/6 of smallest Ricci eigenvalue) then manifold definite. If restricting to a metric with harmonic Weyl tensor, it must be self-dual or anti-self-dual same conditions. Similarly, if an Einstein metric, either complex project...

part. On admission the patient was pale, thin, weak, and exhausted. Her face wore a pinched and anxious expression, indicative of prolonged suffering. For several months before admission, she had been unable to walk on the limb. The foot presented a thickened, clubbed appearance. On the dorsal surface towards the outer margin, there were several sinuses which discharged a dark, sanious pus, mix...

Using an approach that allows us to probe the electronic structure of strongly pinched-off quantum point contacts (QPCs), we provide evidence for the formation of self-consistently realized bound states (BSs) in these structures. Our approach exploits the resonant interaction between closely coupled QPCs, and demonstrates that the BSs may give rise to a robust confinement of single spins, which...

We show that if a simply connected manifold is almost quarter pinched then it is di¤eomorphic to a CROSS or sphere.