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151.
152.
Pedro G. Massey Mariano A. Ruiz Demetrio Stojanoff 《Linear algebra and its applications》2012,436(3):447-464
We consider reconstruction systems (RS’s), which are G-frames in a finite dimensional setting, and that includes the fusion frames as projective RS’s. We describe the spectral picture of the set of RS operators for the projective systems with fixed weights. We also introduce a functional defined on dual pairs of RS’s, called the joint potential, and study the structure of the minimizers of this functional. In the case of irreducible RS’s the minimizers are characterize as the tight systems. In the general case we give spectral and geometric characterizations of the minimizers of the joint potential. At the end of the paper we show several examples that illustrate our results. 相似文献
153.
154.
155.
J. L. Jiménez Pérez E. Rangel Vargas R. Gutiérrez Fuentes A. Cruz-Orea H. Bautista de León 《The European physical journal. Special topics》2008,153(1):511-513
In this paper we used thermal lens spectrometry to
determine the thermal diffusivity of cheese fats. We have used equal
concentrations of cheese fats from oaxaca, chihuahua, gouda, manchego and
mozzarella cheeses at 42°C temperature. The two lasers
mismatched mode experimental configuration was used with a He-Ne laser, as a
probe beam and an Ar+ laser as the excitation one. The characteristic
time constant of the transient thermal lens was obtained by fitting the
theoretical expression to the experimental data in order to obtain the
thermal diffusivity of the cheese fat samples. This measured thermal
property may contribute to a better understanding of the cheese fats
quality, which is very important in food industry. 相似文献
156.
157.
158.
Reyes-Chilpa R Jiménez-Estrada M Godínez MV Hernández-Ortega S Campos M Béjar E 《Natural product letters》2002,16(4):239-242
A new cacalolide sesquiterpenoid, named as Romo-A, was isolated from the roots of Psacalium decompositum, Asteraceae, a Mexican medicinal shrub with antidiabetic properties. Its structure was elucidated by NMR, MS, IR, UV, and confirmed by X-ray diffraction studies. 相似文献
159.
Avalos M Babiano R Cintas P Clemente FR Gordillo R Hursthouse MB Jiménez JL Light ME Palacios JC 《The Journal of organic chemistry》2002,67(7):2378-2381
The present contribution discloses a simple and unexpected acid-catalyzed cleavage of tetrahydrotetrazines leading to 1,2-bis(hydrazones). Incorporation of a chiral fragment derived from carbohydrates enables the rapid preparation of glycosazones, a family of compounds employed by Emil Fischer to elucidate the configuration of sugars. In addition, a mechanistic proposal accounts for experimental observations. 相似文献
160.
Delgado J Espinós A Jiménez MC Miranda MA 《Chemical communications (Cambridge, England)》2002,(22):2636-2637
Formation of an o-quinone methide via C-C fragmentation of a zwitterion formed by intramolecular excited state proton transfer from an o-allylphenol derivative is reported for the first time. 相似文献