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141.
Complexes [Pd(3)(mu(3)-S)(mu(3)-X)(L)(3)] (L = orthometalated imine), obtained by an unusual reaction of mu(2)-OH dimeric complexes and CS(2), are an unprecedented type of asymmetrical bridges between metallatriangles, which force an all-cis arrangement of the three orthometalated ligands relative to the metallatriangle. 相似文献
142.
Raúl Ferreira Pablo Groisman Julio D. Rossi 《Numerical Methods for Partial Differential Equations》2004,20(4):552-575
We study numerical approximations of positive solutions of the porous medium equation with a nonlinear source, where m > 1, p > 0 and L > 0 are parameters. We describe in terms of p, m, and L when solutions of a semidiscretization in space exist globally in time and when they blow up in a finite time. We also find the blow‐up rates and the blow‐up sets, proving that there is no regional blow‐up for the numerical scheme. © 2004 Wiley Periodicals, Inc. Numer Methods Partial Differential Eq, 2004 相似文献
143.
Fabiano?B.?BritoEmail author Pablo?M.?Chacón A. M.?Naveira 《Commentarii Mathematici Helvetici》2004,79(2):300-316
A unit vector field X on
a Riemannian manifold determines a submanifold in the unit
tangent bundle. The volume of X is
the volume of this submanifold for the induced
Sasaki metric. It is known that the parallel fields are the trivial minima.
In this paper, we obtain a lower bound for the volume in terms
of the integrals of the 2i-symmetric
functions of the second fundamental form of the
orthogonal distribution to the field X.
In the spheres ${\textbf {S}}^{2k+1}$, this lower bound is independent of
X.
Consequently, the volume of a unit vector
field on an odd-sphere is always greater than the volume of the radial field.
The main theorem on volumes is applied also to hyperbolic
compact spaces, giving a non-trivial lower bound of the volume of unit fields. 相似文献
144.
In this work we have combined a Wang-Landau sampling scheme [F. Wang and D. Landau, Phys. Rev. Lett. 86, 2050 (2001)] with an expanded ensemble formalism to yield a simple and powerful method for computing potentials of mean force. The new method is implemented to investigate the mechanical deformation of proteins. Comparisons are made with analytical results for simple model systems such as harmonic springs and Rouse chains. The method is then illustrated on a model 15-residue alanine molecule in an implicit solvent. Results for mechanical unfolding of this oligopeptide are compared to those of steered molecular dynamics calculations. 相似文献
145.
We have developed an aberro-polariscope that simultaneously measures spatially resolved polarization properties and wave-front aberration in a living human eye. The setup consists of an infrared Hartmann-Shack sensor that incorporates a polariscope. A series of four Hartmann-Shack images corresponding to independent polarization states were recorded. The corresponding wave-front aberration was computed from each image. Moreover, from each set of four images spatially resolved (over the pupil plane) parameters of polarization were also determined. This instrument allows useful information on both the optical and the biomechanical properties of the eye to be obtained. 相似文献
146.
We have observed lasing in a complicated eigenmode of a quasi-stadium laser diode with an unstable resonator consisting of two curved end mirrors obeying an unstable resonator condition and two straight sidewall mirrors. The laser was fabricated by application of a reactive-ion-etching technique to a molecular beam epitaxy-grown graded-index separate-confinement heterostructure single-quantum-well GaAs/AlGaAs structure. The far-field pattern shows that the lasing mode corresponds to the complicated lowest-loss mode obtained numerically by an extended Fox-Li method. 相似文献
147.
Fantuzzi G Pengo P Gomila R Ballester P Hunter CA Pasquato L Scrimin P 《Chemical communications (Cambridge, England)》2003,(8):1004-1005
N-Methylimidazole-functionalized gold nanoparticles behave as multivalent ligands for porphyrin arrays with an increase in binding strength of up to three order of magnitude with respect to a monovalent system. 相似文献
148.
A novel organic-inorganic hybrid based on a dinuclear copper complex supported on a keggin polyoxometalate 总被引:1,自引:0,他引:1
Reinoso S Vitoria P Lezama L Luque A Gutiérrez-Zorrilla JM 《Inorganic chemistry》2003,42(12):3709-3711
The autoassembly process of copper-oxalate dimers and Keggin type polyoxometalates leads to the first example of a new family of organic-inorganic hybrids, K(14)[(Cu(2)(bpy)(2)(mu-ox))(SiW(11)O(39)Cu(H(2)O))](2)[SiW(11)O(39)Cu(H(2)O)]. approximately 55H(2)O. This compound crystallizes in the monoclinic space group C2/m, a = 37.932(6) A, b = 21.303(3) A, c = 12.546(2) A, beta = 106.16(1) degrees, Z = 2. The crystal structure reveals the presence of a polymeric hybrid built up of alternating dimer and polyoxometalate entities. 相似文献
149.
Alonso MA Casares JA Espinet P Soulantica K Orpen AG Phetmung H 《Inorganic chemistry》2003,42(12):3856-3864
The stereochemistry of the chelate rings of a number of rhodium aminophosphine complexes is studied by NMR spectroscopy. The similarity in the variable-temperature behavior for the different compounds is consistent with them having in common highly preferred chelate ring conformations. The six-membered metallacycle of coordinated (R)-PN (PN = o-diphenylphosphino-alpha-methyl-N,N-dimethylbenzylamine) adopts a delta conformation in the solid state. NMR experiments indicate that this conformation is strongly favored in solution as well. The preferred sense of helicity is imposed by the absolute configuration of the stereogenic carbon atom on the ligand, which exerts an important steric control. The complex [Rh(TFB)((C(6)H(4)CHMeNMe(2))(2)P(C(6)H(4)CHMeNHMe(2)))](BF(4))(2).H(2)O.Me(2)CO crystallizes in the monoclinic space group P2(1) with a = 12.0548(11) A, b = 16.139(2) A, c = 12.1804(10) A, beta = 100.742(9) degrees, Z = 4. 相似文献
150.
Alencar Raymundo; Aron Richard; Galindo Pablo; Zagorodnyuk Andriy 《Bulletin London Mathematical Society》2003,35(1):55-64
The authors study the algebra of uniformly continuous holomorphicsymmetric functions on the ball of lp, investigating in particularthe spectrum of such algebras. To do so, they examine the algebraof symmetric polynomials on lp-spaces, as well as finitely generatedsymmetric algebras of holomorphic functions. Such symmetricpolynomials determine the points in lp up to a permutation. 相似文献