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181.
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Simon M. Doughty J.Fraser Stoddart Howard M. Colquhoun Alexandra M.Z. Slawin David J. Williams 《Polyhedron》1985,4(4):567-575
The crystal structure of 2Li picrate.dibenzo-36-crown-12.2H2O was determined by X-ray diffraction methods. The 2:1 (metal:ligand) complex crystalli 相似文献
184.
185.
J.L. Osborne C.A. Barnes R.W. Kavanagh R.M. Kremer G.J. Mathews J.L. Zyskind P.D. Parker A.J. Howard 《Nuclear Physics A》1984,419(1):115-132
Cross sections for the 3He(α, γ)7Be reaction have been measured at several energies from Ec.m. = 165 to 1169 keV by counting prompt γ-rays from a windowless, differentially pumped, recirculating, 3He gas target. The cross-section factor S34(Ec.m.) and branching ratio γ1/γ0 were determined at each energy. Cross sections were also measured at Ec.m. = 947 and 1255 keV by counting the γ-rays from the 7Be produced in a 3He gas cell with a Ni entrance foil. Combining the results of these two independent experiments yields a zero-energy intercept for the cross-section factor of S34(0) = 0.53 ± 0.03 keV · b. The relationship between these measurements and several theoretical calculations, and the import of the extrapolated cross section for the solar-neutrino problem are discussed. 相似文献
186.
187.
Howard Sachar 《Geometriae Dedicata》1979,8(4):407-415
This paper investigates the F span of the rows of an incidence matrix of a finite projective plane. Results are obtained on the dimension and minimum weight (in the sense of algebraic coding theory) of both this span and its orthogonal. 相似文献
188.
The experimental charge density distribution of dimethyl-trans-2-oxohexahydro-pyrimidine-4,6-dicarboxylate 1 has been determined using single-crystal X-ray diffraction data measured at 100 K, in terms of the rigid-pseudoatom formalism. Multipole refinement converged at R(F) = 0.034 for 7283 reflections with I > 3 sigma (I) and sin theta/lambda < or = 1.13 A(-1). Covalent and hydrogen bonding interactions are analyzed using a topological analysis of the Laplacian of the charge density. The experimentally derived electrostatic potential mapped onto the reactive surface of the molecule reveals the potential binding sites of 1. 相似文献
189.
Mechanism for flow-rate controlled breakup in confined geometries: a route to monodisperse emulsions 总被引:1,自引:0,他引:1
This Letter describes a quasistationary breakup of an immiscible, inviscid fluid at low capillary numbers. The breakup proceeds in a coflowing, viscous liquid, in a confined geometry of a long and narrow orifice. In contrast to the capillary instability in an unbounded fluid, the collapse proceeds through a series of equilibria, each yielding the minimum interfacial energy of the fluid-fluid interface. The process is slow in comparison to typical relaxation speeds of the interface, and it is reversible. Its quasistatic character of collapse forms the basis for controlled, high-throughput generation of monodisperse fluid dispersions. 相似文献
190.
The free energy plays a fundamental role in statistical and condensed matter physics. A related notion of free energy plays
an important role in the study of hyperbolic dynamical systems. In this paper we introduce and study a natural notion of free
energy for surfaces with variable negative curvature. This geometric free energy encodes a new type of marked length spectrum
of closed geodesics, which lies between the well-known marked length spectrum (marked by the corresponding element of the
fundamental group) and the unmarked length spectrum. We prove that the free energy parametrizes the boundary of the domain
of convergence of a Poincaré series which also encodes this spectrum. We also show that this new length spectrum, or equivalently
the geometric free energy, is not an isometry invariant. In the final section we use tools from multifractal analysis to effect
a fine asymptotic comparison of word length and geodesic length of closed geodesics. We hope that our geometric understanding
of free energy will provide new insight into this fundamental physical and dynamical quantity.
The work of the second author was partially supported by a National Science Foundation grant DMS-0355180. This work was completed
during a visit by the first author to Penn State as a Shapiro Fellow. 相似文献