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101.
Ab initio investigation of multiplet spectrum of lanthanides in archetypal coordination geometries shows an unexpected regular structure consisting of (i) mirror symmetry of anisotropic magnetic properties of doublet states, (ii) high magnetic axiality of low-lying and high-lying doublets, comparable to complexes with ideal axial symmetry, and (iii) the strong rotation of the anisotropy axes of individual doublets. The obtained high axiality of the ground doublet states explains the SMM behaviour of low-symmetry lanthanide complexes. 相似文献
102.
103.
Ghenadie Novitchi Dr. Wolfgang Wernsdorfer Prof. Dr. Liviu F. Chibotaru Prof. Dr. Jean‐Pierre Costes Dr. Christopher E. Anson Dr. Annie K. Powell Prof. Dr. 《Angewandte Chemie (International ed. in English)》2009,48(9):1614-1619
Propelling magnetism : Supramolecular organization leads to a remarkable dodecanuclear {Cu3Dy3}2 cluster with a “double–propeller” shape (see picture). The linkages of the CuDy units, both intramolecular and supramolecular, appear to be responsible for a drastic change in the single molecule magnetic behavior.
104.
105.
Ion Mihai Liviu Nicolescu Radu Rosca 《Rendiconti del Circolo Matematico di Palermo》1999,48(2):223-236
Paracontact and para Sasakian manifoldsM carryingr(1<r≤dimM) Reed vector filds ξ
r
have been especially studied by A. Bucki [2], [3], [4].
In the present paper, we consider a (2m+2)-dimensional para Sasakian manifoldM(ϕ, ξ
r
, η
r
g), whose Reed convectors η
r
=ξ
r
b
are exact 1-forms and the covariant derivatives of ξ
r
are given by ∇ξ
r
=f
r
dp
⊺, wheredp
⊤ means the horizontal component of the soldering formdp andf
r∈C∞M satisfydf
r
=cη
r
,c=constant.
It is proved that such a manifold may be viewed as the local Riemannian productM=M
⊥×M⊤, where
It is pointed-out thatM can not be compact.
Some distinguished vector fields onM are constructed and infinitesimal transformations induced by them on the Lie algebra are discussed. 相似文献
i) | M ⊥ is a flat surface tangent to ξ r ; |
ii) | M ⊤ is a pseudo-umbilical 2m-dimensional submanifold, having ξ=f r ξ r as mean curvature vector field. |
106.
Kieran AL Pascu SI Jarrosson T Sanders JK 《Chemical communications (Cambridge, England)》2005,(10):1276-1278
A new, highly flexible porphyrin dimer was isolated in preparative scale from a dynamic disulfide library; this receptor adjusts to fit guests with a wide range of steric requirements and, whilst C60 proved to be an unsuitable template for this library, a new C60-porphyrin complex was isolated and characterised. 相似文献
107.
The temperature dependence and relaxation function breadth of segmental dynamics (α-relaxation) for 1,2-polybutadiene and 1,4-polybutadiene are used to predict their respective temperature-dependent terminal relaxation times by unified application of the Ngai coupling model. Literature results for the terminal flow of near-monodisperse linear polybutadienes having widely varying molecular weights are successfully represented using the coupling model by variation of only a single parameter, C, which is the proportionality constant between the longest Rouse relaxation time and the primitive relaxation time which underlies the cooperative segmental process. The value of C varies with molecular weight (M) according to C ∝ Mb where b is found to range from 1.8 to 2.1, in close agreement with the expected exponent of 2. Contrary to experimental data and coupling model predictions, reptation theory predicts identical influences of temperature on Rouse and terminal relaxation processes; we suggest that invoking a temperature dependence for contour length fluctuations, and hence number of effective entanglements per chain, may resolve this deficiency of the tube model. 相似文献
108.
Liviu Brndeu 《Chaos, solitons, and fractals》2000,11(15):2493-2503
In many other papers a new direct method is developed for the study of vibro-impact system stability, a case in which the stability conditions are directly and rapidly obtained. This new method is stated and applied for systems with one or several degrees of freedom whose motion is analysed by Lagrange's equations. Thus, the equations in variations determined from the differential equations are considered, which by applying the boundary conditions lead by integration to the linearized equation in perturbations necessary to write the stability conditions. As example, is analysed in detail a particular case with one degree of freedom realised by the rod-crank mechanism. Also, a general system with two degrees of freedom is completely studied. 相似文献
109.
Liviu I. Nicolaescu 《Functional Analysis and Other Mathematics》2006,1(1):85-91
We answer a question of Arnold concerning the growth rate of the number of Morse functions on the two-sphere.
This work was supported in part by the NSF (Grant No. DMS-0303601). 相似文献
110.
In this paper we study a nonlocal equation that takes into account convective and diffusive effects, ut=J∗u−u+G∗(f(u))−f(u) in Rd, with J radially symmetric and G not necessarily symmetric. First, we prove existence, uniqueness and continuous dependence with respect to the initial condition of solutions. This problem is the nonlocal analogous to the usual local convection-diffusion equation ut=Δu+b⋅∇(f(u)). In fact, we prove that solutions of the nonlocal equation converge to the solution of the usual convection-diffusion equation when we rescale the convolution kernels J and G appropriately. Finally we study the asymptotic behaviour of solutions as t→∞ when f(u)=|u|q−1u with q>1. We find the decay rate and the first-order term in the asymptotic regime. 相似文献