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51.
Mihaela Antonina Calin Ileana Carmen Boiangiu Sorin Viorel Parasca Sorin Miclos Dan Savastru Dragos Manea 《光谱学快报》2017,50(3):150-155
In this paper, we present a new method for the assessment of skin flap perfusion based on the non-invasive monitoring of skin blood oxygenation using hyperspectral imaging. This method consists of generation of oxyhemoglobin and deoxyhemoglobin maps in skin flap from hyperspectral image using an analytic model based on Beer–Lambert law. The results obtained on a fasciocutaneous sural flap have revealed that the oxyhemoglobin and deoxyhemoglobin maps facilitate the visualization of some differences between different areas of the flap, an aspect that clinical examination fails to do. In conclusion, the proposed method could provide a new option for a more accurate assessment of flap survival. 相似文献
52.
Mihaela M. ManeaIoan V. Moise Marian VirgoliciConstantin D. Negut Olimpia-Hinamatsuri BarbuMihalis Cutrubinis Viorel FugaruIoana R. Stanculescu Corneliu C. Ponta 《Radiation Physics and Chemistry》2012,81(2):160-167
The degradation of cultural heritage objects by insects and microorganisms is an important issue for conservators, art specialists and humankind in general. Gamma irradiation is an efficient method of polychrome wooden artifacts disinfestation. Color changes and other modifications in the physical chemical properties of materials induced by gamma irradiation are feared by cultural heritage responsible committees and they have to be evaluated objectively and precisely. In this paper FTIR and FT-Raman spectroscopy methods were used to investigate the structural changes in some experimental models of tempera paint layers on wood following 11 kGy gamma irradiation at two dose rates. Radiation chemistry depends on the particular pigment, matrix formed by protein, resin (in case of varnished samples) and water presence. For the majority of painted layer in experimental models very small spectral variations were observed. Small changes in the FTIR spectra were observed for the raw sienna experimental model: for the higher dose rate the egg yolk protein oxidation peaks and the CH stretching bands due to lipids degradation products increased. 相似文献
53.
The interaction between graphene and a SiO(2) surface has been analyzed with first-principles DFT calculations by constructing the different configurations based on α-quartz and cristobalite structures. The fact that single-layer graphene can stay stably on a SiO(2) surface is explained based on a general consideration of the configuration structures of the SiO(2) surface. It is found that the oxygen defect in a SiO(2) surface can shift the Fermi level of graphene down which opens up the mechanism of the hole-doping effect of graphene adsorbed on a SiO(2) surface observed in a lot of experiments. 相似文献
54.
Vera Balan Ivona Andreea Petrache Marcel Ionel Popa Maria Butnaru Eugen Barbu John Tsibouklis Liliana Verestiuc 《Journal of nanoparticle research》2012,14(2):730
Haemocompatible biotinylated superparamagnetic nanoparticles (size range 300–700 nm) have been obtained by coating magnetite
through ionic gelation with a mixture of chitosan and sodium tripolyphosphate, followed by subsequent functionalisation with
biotin. The evaluations of their magnetic properties together with haemocompatibility tests have shown that these nanoparticles
exhibit the prerequisite behaviour for use in magnetic field–assisted separations within biological systems. 相似文献
55.
Marcela Stoia Mircea Stefanescu Mirela Barbu Paul Barvinschi Lucian Barbu-Tudoran 《Journal of Thermal Analysis and Calorimetry》2012,108(3):1041-1049
The present study deals with preparation and characterization of spinel mixed oxide systems NiM 2 III O4, where MIII?=?FeIII, CrIII. In order to obtain 50% NiFe2O4/50% SiO2 and 50% NiCr2O4/50% SiO2 nanocomposite, we have used a versatile route based on the thermal decomposition inside the SiO2 matrix, of some particular precursors, coordination compounds of the involved MII and MIII cations with dicarboxylate ligands. The ligands form in the redox reaction between metal nitrates mixture and 1,3-propanediol at the heating around 140?°C of the gels (tetraethylorthosilicate?Cmetal nitrates?C1,3-propanediol?Cwater). The as-obtained precursors, embedded in silica gels, have been characterized by FT-IR spectrometry and thermal analysis. Both precursors thermally decompose up to 350?°C leading to the formation of the corresponding metal oxides inside the silica matrix. X-ray diffraction of the annealed powders have evidenced the formation of NiFe2O4 starting with 600?°C, and NiCr2O4 starting with 400?°C. This behavior can be explained by the fact that, by thermal decomposition of the Fe(III) carboxylate at 300?°C, the spinelic phase ??-Fe2O3 is formed, which interacts with the NiO, forming the ferrite nuclei. By thermal decomposition of chromium carboxylate, a nonstoichiometric chromium oxide (Cr2O3+x ) is formed. In the range 380?C400?°C, Cr2O3+x turns into Cr2O3 which immediately interacts with NiO leading to the formation of nickel chromites nuclei inside the pores of silica matrix. Both spinels have been obtained as nanocrystalites homogenously dispersed as resulted from XRD and TEM data. 相似文献
56.
57.
Summary
We give some existence results far Hamilton-Jacobi equations in Hilbert spaces using a variational and a semi-group approach. 相似文献
58.
We study the existence theory for parabolic variational inequalities in weighted L
2 spaces with respect to excessive measures associated with a transition semigroup. We characterize the value function of optimal
stopping problems for finite and infinite dimensional diffusions as a generalized solution of such a variational inequality.
The weighted L
2 setting allows us to cover some singular cases, such as optimal stopping for stochastic equations with degenerate diffusion
coefficient. As an application of the theory, we consider the pricing of American-style contingent claims. Among others, we
treat the cases of assets with stochastic volatility and with path-dependent payoffs. 相似文献
59.
Barbu C. Kestenband 《Geometriae Dedicata》1992,44(2):123-126
We show that the sets of absolute points of correlations of Desarguesian projective planes do not possess the so-called Pasch (O'Nan) configuration. Previously, this has been known of unitary polarities of planes of square order.This research was supported by New York Institute of Technology. 相似文献
60.