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221.
Abstract Results on the temperature- and pressure dependence of the specific volume, thermal expansivity and compressibility of elastomeric compounds are reported. 相似文献
222.
223.
Jeffrey P. Emerson Daniel A. Wright Robert A. Fisher Norman E. Phillips 《Czechoslovak Journal of Physics》1996,46(3):1209-1210
The specific heat and magnetic susceptibility of a sample of YBa2Cu3O7?δ (YBCO) was measured for 0≤δ≤0.85, 0.8≤T≤120K, and H=0, 3, 5, 7, 9T. The data show the existence of both S=1/2 and S=2 paramagnetic centers, consistent with EPR results. The δ dependences of their concentrations and of other parameters are reported. 相似文献
224.
We investigate the quality of solutions obtained from sample-average approximations to two-stage stochastic linear programs
with recourse. We use a recently developed software tool executing on a computational grid to solve many large instances of
these problems, allowing us to obtain high-quality solutions and to verify optimality and near-optimality of the computed
solutions in various ways.
Research supported by the Mathematical, Information, and Computational Sciences Division subprogram of the Office of Advanced
Scientific Computing Research, U.S. Department of Energy, under Contract W-31-109-Eng-38, and by the National Science Foundation
under Grant 9726385.
Research supported by the Mathematical, Information, and Computational Sciences Division subprogram of the Office of Advanced
Scientific Computing Research, U.S. Department of Energy, under Contract W-31-109-Eng-38, and by the National Science Foundation
under Grant DMS-0073770.
Research supported by the Mathematical, Information, and Computational Sciences Division subprogram of the Office of Advanced
Scientific Computing Research, U.S. Department of Energy, under Contract W-31-109-Eng-38, and by the National Science Foundation
under Grants 9726385 and 0082065. 相似文献
225.
226.
J. D. Maitland Wright 《Communications in Mathematical Physics》1998,191(3):493-500
Gell–Mann and Hartle have proposed a significant generalisation of quantum theory in which decoherence functionals perform
a key role. Verifying a conjecture of Isham–Linden–Schreckenberg, the author analysed the structure of bounded, finitely additive,
decoherence functionals for a general von Neumann algebra A (where A has no Type I2 direct summand). Isham et al. had already given a penetrating analysis for the situation where A is finite dimensional. The assumption of countable additivity for a decoherence functional may seem more plausible, physically, than that of boundedness. The results of this note are
obtained much more generally but, when specialised to L(H), the algebra of all bounded linear operators on a separable Hilbert space H, give:
Let d be a countably additive decoherence functional defined on all pairs of projections in L(H). If H is infinite dimensional then d must be bounded. By contrast, when H is finite dimensional, unbounded (countably additive)
decoherence functionals always exist for L(A).
Received: 6 December 1996 / Accepted: 18 May 1997 相似文献
227.
D. Sieger H. Tietze-Jaensch R. Geick W. Zulehner A. F. Wright A. de Geyer 《Applied Physics A: Materials Science & Processing》1991,53(5):422-425
Czochralski grown silicon crystals contain interstitially dissolved oxygen which diffuses on heating to form precipitates of silica. We have examined these precipitates by small angle neutron scattering (SANS) in the Q-range 0.05 Å–1<Q<0.4 Å–1. The obtained SANS patterns reveal pronounced anisotropic intensity distributions which resemble the symmetry of the host crystal. The SANS spectra show an anisotropic central peak at Q<0.1 Å–1 due to the single particle shape and a number of weak intensities for larger Q-values. These weak side maxima are considered correlation peaks or quasi-elastic interference peaks. They show, however, an unexpected and distinct temperature dependence: with decreasing temperature below values of 220 K their intensity is lost slowly, but reversibly. At T = 50 K only the central peak from the single-particle scattering remains unchanged. Upon heating, the correlation peaks regain their former value of intensity and Q-position without any evidence of thermal hysteresis. 相似文献
228.
Mike Wright 《The Journal of the Operational Research Society》1992,43(3):195-201
Each team in the English County Cricket Championship plays against some other teams twice a year, and others only once. This paper describes a case study whose aim was to overcome this inherent unfairness by producing a four-year schedule of opponents which was as fair as possible, and could be easily seen to be fair, while still allowing for traditional rivalries. The schedule also needed to be satisfactory in regard to several other constraints and objectives. Various simple heuristics were used; these are described in some detail. Of particular interest is the effectiveness of a ‘local non-worsening’ approach when the objective is to find any feasible solution. This is equivalent to simulated annealing at a constant temperature of absolute zero. 相似文献
229.
Nick Wright 《Journal of Functional Analysis》2005,220(2):265-303
The C0 coarse structure on a metric space is a refinement of the bounded structure and is closely related to the topology of the space. In this paper we will prove the C0 version of the coarse Baum–Connes conjecture and show that K*(C*X0) is a topological invariant for a broad class of metric spaces. Using this result we construct a ‘geometric’ obstruction group to the coarse Baum–Connes conjecture for the bounded coarse structure. We then show under the assumption of finite asymptotic dimension that the obstructions vanish, and hence we obtain a new proof of the coarse Baum–Connes conjecture in this context. 相似文献
230.