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Time-optimal control of a parabolic system with time lags given in the integral form 总被引:1,自引:0,他引:1
KOWALEWSKI ADAM; KRAKOWIAK ANNA 《IMA Journal of Mathematical Control and Information》2000,17(3):209-225
In this paper the time-optimal control problem for a distributedparabolic system in which time lags appear in the integral formboth in the state equation and in the boundary condition ispresented. The particular properties of the optimal controlare discussed. 相似文献
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A Note on Sampling from Combinations of Distributions 总被引:1,自引:0,他引:1
A rejection technique is described for sampling from a combinationof distributions with negative weights for some of the components. 相似文献
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The paper deals with the notions of weak stability and weak generalized convolution with respect to a generalized convolution, introduced by Kucharczak and Urbanik. We study properties of such objects and give examples of weakly stable measures with respect to the Kendall convolution. Moreover, we show that in the context of non-commutative probability, two operations: the q-convolution and the (q,1)-convolution satisfy the Urbanik??s conditions for a generalized convolution, interpreted on the set of moment sequences. The weak stability reveals the relation between two operations. 相似文献
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Electronic absorption spectra of crystals and solutions of praseodymium and thulium acetates and dipicolinates are reported. The influence of spectral properties of both ligands on intensities of the f—f transitions in the crystals studied is discussed. In the near-IR region, overtone vibrations of ligands are strongly coupled with the f—f transitions, particularly with the hypersensitive ones. In the UV spectral range, absorption bands of the π → π?, n → π? and possible charge transfer of metal ? ligand transitions affect f—f transitions and should also be taken into account. The phenomenological Judd—Ofelt parameters evaluated for praseodymium complexes in solution and crystals are meaningless, because no set of intensities unbiased by ligand transitions and/or neighbouring f-d configurations is available. For Tm3+ compounds the Judd-Ofelt analysis has given quite good results, however no significant influence of the metal ion environment changes on the Ωλ parameters can be observed. 相似文献
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ROSANNA GRASSI SILVANA STEFANI ANNA TORRIERO 《The Journal of mathematical sociology》2013,37(3):237-248
In this article we establish new results on the components of the principal eigenvector in an undirected graph. Those results are particularly significant in relation to the concept of centrality in social networks. In particular degree centrality and eigenvector centrality are compared. We find further conditions, based on the spectral radius, on which nodes with highest degree centrality are also the most eigencentral. 相似文献
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Analytical chemistry does play a key role in the chemical characterization of the environment and it appears that X-ray spectrometry,
in its many forms, is one of the most relevant analytical techniques in preventive conservation, as it is in cultural heritage
research in general. X-ray spectrometry has indeed been the method of choice for the characterization of the inorganic composition
of atmospheric aerosols, for a long time. 相似文献
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Abstract— Photophysical and photochemical properties of 1H-indenylfuran and thiophene derivatives were studied. UV spectra showed that all the compounds tested absorbed UV light in the region 350–380 nm. The fluorescence spectra of 4a-e showed bands in the region 410–470 nm and quantum yields (φF ) in the range 0.25–0.88. Attempts to calculate the triplet energy of 4a-e failed except for 4c and 4d , which showed ET = 43–44 kcal mol-1 . These compounds are a new class of singlet oxygen sensitizers. The sensitized reaction of 2,5-dimethylfuran with singlet oxygen was followed showing that 4a and 4e are more reactive than α-terthiophene (4.0 and 2.5 times respectively), while the other compounds show the same reactivity as 1 . This behavior can be explained considering the different intersystem crossing quantum yields of compounds 4a-e . Diazabicyclo[2. 2. 2]octane is a quencher of singlet oxygen in this reaction, while we can exclude superoxide ion formation using the photooxidation of α, α-dimethylstilbene. 相似文献
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ANNA M. RICHTER STEPHEN YIP ELIZABETH WATERFIELD PATRICIA M. LOGAN CHARLES E. SLONECKER JULIA G. LEVY 《Photochemistry and photobiology》1991,53(2):281-286
A comparative study, at both the macroscopic and microscopic level, of skin photosensitivity caused by four isomeric forms of benzoporphyrin derivative (BPD) has been carried out, and compared to effects of Photofrin. Animals injected intravenously with BPD analogues and exposed to light 3 h later showed extensive photosensitivity. Animals receiving the monoacid derivatives of BPD (BPD-MA and BPD-MB) showed markedly more photosensitivity than those receiving the diacid derivatives (BPD-DA and BPD-DB). Animals receiving BPD analogues which were exposed to light 24 h or more later showed only minimal reactivity. Histological examination of biopsies taken after photosensitizer injection and light exposure showed extensive changes in epidermis and dermis, including epidermal erosion, degranulation of the stratum granulosum, spongiosis, depletion in cellularity and mast cell degranulation. These changes were noted to be similar to changes caused by Photofrin. 相似文献
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