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971.
The Herrlich's problem from [8] whether there are nontrivial classes of topological spaces that are both almost reflective or injective and almost coreflective or projective, is investigated in a more general setting using cone and cocone modifications of the classes used in the problem. We look also at the problem for uniform spaces. Typical results: There is no nontrivial multiprojective and orthogonal class of topological spaces; There is a reflective class of uniform spaces that is almost coreflective in Unif.Work on this paper was initiated while the first author was a C.N.R. visitor of the University of L'Aquila. Partial financial assistence by Charles University Grant 349/1994 is also acknowledged. 相似文献
972.
Anna B. Druzhko † David J. Vanderah Baldwin Robertson Howard H. Weetall 《Photochemistry and photobiology》1996,64(5):867-869
Abstract— The photoinduced changes of absorbance as well as proton release and uptake have been observed for an azulenic analog of wild-type bacteriorhodopsin. The release and uptake of protons have been measured using a highly sensitive electrochemical technique. Bacteriorhodopsin membrane patches on a tin-oxide electrode produce a transient photocurrent that is negative for proton release and positive for proton uptake. For azulenic bacteriorhodopsin the photocurrent is approximately 20% of the transient observed with native bacteriorhodopsin. The existence of the photoinduced absorbance changes and the transient photocurrent are important results for gaining further insight into the photoinduced function of bacteriorhodopsin. 相似文献
973.
This paper shows that market equilibrium problems of production may generally be modelled as equilibrium flow problems in networks and that their equilibrium conditions can be visualized as a variational inequality. This connection would allow us to transplant directly elements of the well-developed theory of equilibrium flow in networks to the theory of market equilibrium. 相似文献
974.
975.
Let G be a free group with r generators, 1 < r < ∞. All the eigenfunctions of an operator on G which plays the same role of the Laplace Beltrami operator on semisimple Lie groups are characterized. Furthermore, an analytic family of representations πz of G on functions on the boundary Ω is considered, defined by , where p(x, ω) is the Poisson kernel relative to the action of G on Ω. It is proved that, for 0 < s = Re z < 1, πz is uniformly bounded on an appropriate Hilbert space . Finally the uniform boundedness of other special representations of G, obtained by considering the free group either as a subgroup of the group of all isometries of a tree or as a subgroup of GL(2, Qp) is proved. 相似文献
976.
Giampaolo Giacomelli Luciano Lardicci Carlo Bertucci Anna Maria Caporusso 《Tetrahedron》1978,34(13):2015-2020
The synthesis and the physical properties of some optically active 1,4-dialkylbuta-1,3-dienes are reported. The synthetic processes employed were essentially stereospecific. NMR, UV and CD spectra of these compounds provide information on the main conformation of the conjugated diene system, which was shown to be s-trans planar. 相似文献
977.
Giorgio Peyronel Anna Pignedoli Wanda Malavasi 《Journal of chemical crystallography》1982,12(6):481-488
The crystal and molecular structure of 3,5-diamino-1,2,4-dithiazolium bromide has been refined from three-dimensional counter data (856 reflections) by least-squares methods, anisotropically for the nonhydrogen and isotropically for the hydrogen atoms, to a finalR=0.036:a=9.948(1),b=12.731(1),c=5.098(1) Å, B=98.70(1)° at 18°C,Z=4,P21/n. The S-S (2.075 Å) distance is intermediate between those of the thiouret hydrochloride and hydroiodide. The C-N(terminal) and C-N(bridging) distances are close to their average value (1.322 Å) within their standard deviations. Thev(NH2) and (NH2) frequencies of the thiouret hydrohalides are close to those of dithiobiuret while thev(NH) and (NH) bands are, as expected, absent. Thev(CN) andv(CS) bands are shifted to higher and lower frequencies, respectively, while a newv(SS) broad band is observed in the 430–410 cm–1 region. 相似文献
978.
979.
Anna Maria Venezia Ronald G. Cavell 《Journal of Electron Spectroscopy and Related Phenomena》1985,36(3):281-296
Photoelectron and Auger (MNN) spectra of tetramethyltin and hexamethylditin have been measured and the results compared to those of metallic tin. Energies and intensities of the Auger lines are in agreement with theory based on an Intermediate Coupling scheme since LS coupling theory was inadequate. Relaxation contributions have been evaluated. 相似文献
980.
Using light-front dynamics, and the notion of the running effective quark mass, we propose a model of the three-quark nucleon wave function, which accounts simultaneously both for the low and the high energy experimental data. Our wave function is a product of a spinor part, inferred from the QCD sum rules, and a gaussian scalar factor, taken for simplicity. Including all three Ioffe currents we get from one wave function both the negative neutron charge radius 〈r2〉neutron=-0.108 fm2 and the decreasing d/u ratio in the proton for xBj increasing from 0.5 to 1. 相似文献