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31.
Osvaldo Pessoa Jr. Olival Freire Jr. Alexis De Greiff 《Physics in Perspective (PIP)》2008,10(2):138-162
In 1966 the Brazilian physicist Klaus Tausk (b. 1927) circulated a preprint from the International Centre for Theoretical
Physics in Trieste, Italy, criticizing Adriana Daneri,Angelo Loinger,and Giovanni Maria Prosperi’s theory of 1962 on the measurement
problem in quantum mechanics. A heated controversy ensued between two opposing camps within the orthodox interpretation of
quantum theory, represented by Léon Rosenfeld and Eugene P.Wigner. The controversy went well beyond the strictly scientific
issues, however, reflecting philosophical and political commitments within the context of the Cold War, the relationship between
science in developed and Third World countries, the importance of social skills, and personal idiosyncrasies. 相似文献
32.
The theory of upper and lower bounds is used in conjunction with the “varied-portions approach” (VPA ) of the “many-electron theory of atoms and molecules” (MET ). Upper and lower bounds equations are derived. It is recognized that if a very natural portion of the full variational expression is made stationary, according to (VPA ), a for of Löwdin's lower bound wave equation results. By using the bracketing theorem it is also possible to give lower bounds to the quantities arising from the (VPA ) of (MET ). This will be useful to study in the future the (MET ) pair correlations and to supplement the computational methods currently available with lower bound estimates as well. 相似文献
33.
LetK be ak-set of class [0, 1,m,n]1 of anr-dimensional projective Galois space PG(r, q) of orderq. We prove that: Ifr = 2s (s 2),k = 2s–1 and if through each point ofK there are exactlyq
2(s–1) tangent lines and at most 2s–3
n-secant lines, thenK is a non singular quadric of PG(2s,q). Ifr = 2s–1 (s2),k=2(s–1) +q
s–1 and if at each point ofK there are exactlyq
2s–3 –q
s–2 tangents and at most 2(s–2)+q
s–2
n-secant lines, thenK is a hyperbolic quadric of PG(2s–1,q). 相似文献
34.
With “hat” denoting the Banach envelope (of a quasi-Banach space) we prove that
if 0<p<1, 0<q<1, ℝ, while
if 0<p<1, 1≤q<+∞, ∝, and
if 1≤p<+∞, 0<q<1, ℝ.
Applications to questions regarding the global interior regularity of solutions to Poisson type problems for the three-dimensional
Lamé system in Lipschitz domains are presented. 相似文献
35.
Most methods of measuring the interfacial tension between two immiscible polymers are based on the analysis of the shape
that a drop of one polymer immersed in the other one exhibits under the action of flow or gravity. In such a situation, the
small, yet nonzero mutual solubility between the two polymers acts toward mass transfer between the drop and the surrounding
fluid. In this work, diffusion effects on the interfacial tension of the pair polyisobutylene/polydimethylsiloxane have been
investigated by drop deformation under shear flow. When the drop was made of polyisobutylene, drop size decreased with time
due to diffusion. Drop shrinkage was associated with a significant increase in interfacial tension, until an apparent plateau
value was reached. The effect was attributed to a selective migration of molecular weights, which would act to enrich the
drop with higher molar mass material. To support such an interpretation, drop viscosity was evaluated by drop shape analysis
and it was actually found to increase with time. In some cases, the ratio between drop and continuous phase viscosity became
higher than the critical value for drop breakup in shear flow. Upon inverting the phases (i.e., when the drop was made of
polydimethylsiloxane), no significant transient effects were observed. In the light of these results, the problem of what
are the correct values of interfacial tension and viscosity ratio for a polymer blend of a certain composition will also be
discussed.
Received: 25 January 1999 Accepted: 24 May 1999 相似文献
36.
Raquel da Silva Cabral Andre L. L. Aquino Alejandro C. Frery Osvaldo A. Rosso Jaime A. Ramírez 《Central European Journal of Physics》2013,11(12):1645-1652
Wireless sensor networks are an important technology for making distributed autonomous measures in hostile or inaccessible environments. Among the challenges they pose, the way data travel among them is a relevant issue since their structure is quite dynamic. The operational topology of such devices can often be described by complex networks. In this work, we assess the variation of measures commonly employed in the complex networks literature applied to wireless sensor networks. Four data communication strategies were considered: geometric, random, small-world, and scale-free models, along with the shortest path length measure. The sensitivity of this measure was analyzed with respect to the following perturbations: insertion and removal of nodes in the geometric strategy; and insertion, removal and rewiring of links in the other models. The assessment was performed using the normalized Kullback-Leibler divergence and Hellinger distance quantifiers, both deriving from the Information Theory framework. The results reveal that the shortest path length is sensitive to perturbations. 相似文献
37.
Crystals of MnxC1-xGa2Se4 (0.00 x 0.20) have been grown the vapour phase by chemical transport modified by the t ime variation of the temperature profile procedure. Crystals with dimensions up to 15 × 2 × 2 mm were obtained and characterized by EPR spectroscopy. 相似文献
38.
Meta-learning, or “learning to learn”, refers to techniques that infer an inductive bias from data corresponding to multiple related tasks with the goal of improving the sample efficiency for new, previously unobserved, tasks. A key performance measure for meta-learning is the meta-generalization gap, that is, the difference between the average loss measured on the meta-training data and on a new, randomly selected task. This paper presents novel information-theoretic upper bounds on the meta-generalization gap. Two broad classes of meta-learning algorithms are considered that use either separate within-task training and test sets, like model agnostic meta-learning (MAML), or joint within-task training and test sets, like reptile. Extending the existing work for conventional learning, an upper bound on the meta-generalization gap is derived for the former class that depends on the mutual information (MI) between the output of the meta-learning algorithm and its input meta-training data. For the latter, the derived bound includes an additional MI between the output of the per-task learning procedure and corresponding data set to capture within-task uncertainty. Tighter bounds are then developed for the two classes via novel individual task MI (ITMI) bounds. Applications of the derived bounds are finally discussed, including a broad class of noisy iterative algorithms for meta-learning. 相似文献
39.
Rosa IL Filho PC Neri CR Serra OA de Figueiredo AT Varela JA Longo E 《Journal of fluorescence》2011,21(4):1575-1583
This work reports on the synthesis and characterization of a new complex of Eu3+ with the 3-hydroxypicolinamide ligand (Hhpa). Here we present an approach for obtaining bis[2-carbamoyl(κO)pyridin-3-olato(κO’)]
lanthanide complexes, which were characterized through elemental analysis, thermal analysis, infrared and photoluminescence
spectroscopies (emission, excitation, luminescence lifetimes, quantum efficiencies, Judd-Ofelt parameters and quantum yields).
Although hpa can act as a bidentate ligand in different conformations, the results attest for the occurrence of a unique coordination
site of low symmetry for the Eu3+ ions, in which two anionic hpa ligands coordinate the cations through an O/O chelating system. The phosphorescence of the
synthesized gadolinium complex provides the energy of the triplet state, which is determined to be at 20,830 cm-1 over the ground state. This makes the Hhpa ligand very adequate for sensitizing the Eu3+ luminescence, which leads to a very efficient antenna effect and opens a wide range of applications for the complex in light
emitting organic-inorganic devices. 相似文献
40.