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81.
82.
The structure of linear codes of constant weight 总被引:1,自引:0,他引:1
Jay A. Wood 《Transactions of the American Mathematical Society》2002,354(3):1007-1026
In this paper we determine completely the structure of linear codes over of constant weight. Namely, we determine exactly which modules underlie linear codes of constant weight, and we describe the coordinate functionals involved. The weight functions considered are: Hamming weight, Lee weight, two forms of Euclidean weight, and pre-homogeneous weights. We prove a general uniqueness theorem for virtual linear codes of constant weight. Existence is settled on a case by case basis.
83.
X-ray crystallography identifies the aromatic donor group D = 2,5-dimethoxy-4-methylphenyl to be a suitable redox center for the construction of organic mixed-valence crystals owing to its large structural change attendant upon 1e oxidation to the cation-radical (D*(+)). The combination of cyclic voltammetry, dynamic ESR line broadening, and electronic (NIR) spectroscopy allows the intervalence electron transfer between the redox centers in the mixed-valence system D-br-D*(+) [where br can be an aliphatic trimethylene or an aromatic (poly)phenylene bridge] to be probed quantitatively. Independent measures of the electronic coupling matrix element (H) for D/D*(+) electron exchange via Mulliken-Hush theory accord with the X-ray crystallographic data-both sufficient to consistently identify the various D-br-D*(+) according to the Robin-Day classification. Thus, the directly coupled biaryl D-D*(+) is a completely delocalized cation in class III with the charge distributed equally over both redox centers. The trimethylene- and biphenylene-bridged cations D(CH(2))(3)D*(+) and D(ph)(2)D*(+) with highly localized charge distributions are prototypical class II systems involving moderately coupled redox centers with H approximately equal to 400 cm(-1). The borderline region between class II/III is occupied by the phenylene-bridged cation D(ph)D*(+); and the X-ray, CV, and NIR analyses yield ambivalent H values (which we believe to be) largely a result of an unusually asymmetric (20/80) charge distribution that is polarized between the D/D*(+) redox centers. 相似文献
84.
Soliton squeezing in microstructure fiber 总被引:4,自引:0,他引:4
We demonstrate, for the first time to our knowledge, the generation of squeezed light by means of soliton self-phase modulation in microstructure fiber. We observe and characterize the formation of solitons in the microstructure fiber at 1550 nm. A maximum squeezing of 2.7 dB is observed, corresponding to 4.0 dB after correcting for detection losses. The dependence of this quantum-noise reduction on various system parameters is studied in detail. Features of the microstructure fiber can be exploited for generation of low-energy continuous-variable entangled pulses for use in all-fiber teleportation experiments. 相似文献
85.
Let u(x) xR
q
be a symmetric nonnegative definite function which is bounded outside of all neighborhoods of zero but which may have u(0)=. Let p
x, (·) be the density of an R
q
valued canonical normal random variable with mean x and variance and let {G
x, ; (x, )R
q
×[0,1 ]} be the mean zero Gaussian process with covariance
A finite positive measure on R
q
is said to be in
with respect to u, if
When
, a multiple Wick product chaos
is defined to be the limit in L
2, as 0, of
where
,
denotes the Wick product of the m
j
normal random variables
.Consider also the associated decoupled chaos processes
,
defined as the limit in L
2, as 0, of
where
are independent copies of G
x,.Define
Note that a neighborhood of the diagonals of
in
is excluded, except those points on the diagonal which originate in the same Wick product in (i). Set
One of the main results of this paper is:
Theorem A. If
is continuous on (R
q
)
r
for all
then
is continuous on
.When u satisfies some regularity conditions simple sufficient conditions are obtained for the continuity of
on (R
q
)
r
. Also several variants of (i) are considered and related to different types of decoupled processes. These results have applications in the study of intersections of Lévy process and continuous additive functionals of several Lévy processes. 相似文献
86.
The new difunction ligand, 2-amino-1-cyclopentenedithio-carboxylate(L), was prepared and its coordination chemistry examined to gain further insight into the reactivity of “aromatic” dithio type ligands. Reaction with MoCl4py2 and VOSO4, led to the surprising eight coordinate products ML4. The sp2 hybridization of the ring carbon to which the CS2 moiety is bonded apparently yields a pseudo-aromatic effect on the reactivity of this ligand. The physical properties of these new compounds are discussed. 相似文献
87.
Ultraviolet photoelectron spectroscopy results are shown to distinguish between the surface and bulk electronic structure of a simple metal. The spectra from Sr at low photon energies (long escape depth) is described by the bulk electronic structure; the spectra at ≈10 eV (short escape depth) is described by the surface electronic structure. 相似文献
88.
89.
The photoemission spectra of PtCu alloys of a number of different compositions has been measured. A new method of sample preparation by an interdiffusion technique allowed rapid measurement as a function of composition. The results are in general agreement with the coherent potential approximation to the electronic structures of alloys. 相似文献
90.