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51.
52.
We study the long time dynamics of the Schrödinger equation on Zoll manifolds. We establish criteria under which the solutions of the Schrödinger equation can or cannot concentrate on a given closed geodesic. As an application, we derive some results on the set of semiclassical measures for eigenfunctions of Schrödinger operators: we prove that adding a potential \({V \in C^{\infty} (\mathbb{S}^{d})}\) to the Laplacian on the sphere results in the existence of geodesics \({\gamma}\) such that the uniform measure supported on \({\gamma}\) cannot be obtained as a weak-\({\star}\) accumulation point of the densities \({(|\psi_{n}|^{2} {vol}_{\mathbb{S}^d})}\) for any sequence of eigenfunctions \({(\psi_n)}\) of \({\Delta_{\mathbb{S}^{d}} - V}\). We also show that the same phenomenon occurs for the free Laplacian on certain Zoll surfaces. 相似文献
53.
We analyze the semiclassical evolution of Gaussian wave packets in chaotic systems. We show that after some short time a Gaussian wave packet becomes a primitive WKB state. From then on, the state can be propagated using the standard time-dependent WKB scheme. Complex trajectories are not necessary to account for the long-time propagation. The Wigner function of the evolving state develops the structure of a classical filament plus quantum oscillations, with phase and amplitude being determined by geometric properties of a classical manifold. 相似文献
54.
Photoinduced deformation of azobenzene polyester films 总被引:1,自引:0,他引:1
55.
Laser-Induced Fluorescence at 488 nm Excitation for Detecting Benign and Malignant Lesions in Stomach Mucosa 总被引:1,自引:0,他引:1
Silveira L Betiol Filho JA Silveira FL Zângaro RA Pacheco MT 《Journal of fluorescence》2008,18(1):35-40
This work aims the detection of the histopathologic alterations of in vitro human gastric mucosa using spectral informations
from laser-induced fluorescence spectroscopy (LIFS) technique with excitation at 488 nm (argon laser). A total of 108 biopsies
with endoscopic diagnosis of gastritis and gastric cancer were obtained at the antral gastric region, from 35 patients with
dyspeptic digestive complaints. The biopsies were collected during the endoscopic examination. On each biopsy fragment the
autofluorescence spectrum was collected in two random points, through a fiber-optic catheter coupled to the excitation laser.
The fluorescence emission spectra collected by the fibers were directed to the spectrograph and detected by the CCD camera.
The spectra were then separated in groups (N, normal; LI, light inflammation; MI, moderated inflammation; CA, adenocarcinoma),
based on the histopathology. The ratio between the emission wavelengths 550 and 600 nm was used as a diagnostic parameter.
Analysis of fluorescence spectra was able to identify the normal tissue from adenocarcinoma lesions with 100% of sensibility
and specificity. The ratio intensities between inflammation (light and moderated), although presented significantly statistical
differences when compared to the normal mucosa, do not furnish enough sensibility and specificity for use as an identification
method due to high variations. LIFS, with excitation of 488 nm, could be used in the differentiation of normal tissue and
neoplasic lesions, assisting a less invasive diagnosis. 相似文献
56.
Maddalena Donati Andrea Mondin Zheng Chen Fabricio Mendes Miranda Baraquizio Braga do Nascimento Jr Giulia Schirato 《Natural product research》2015,29(10):939-946
The essential oils (EOs) from the Brazilian species Croton zehntneri, Pterodon emarginatus and Schinopsis brasiliensis were examined for their chemical constituents, and antioxidant and antimicrobial activities. The composition of EOs was determined by using gas chromatography coupled with mass spectrometry analysis, while the antioxidant activity was evaluated through the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and oxygen radical absorbance capacity (ORAC) assays. Furthermore, the antimicrobial activity was investigated against Escherichia coli and Pseudomonas aeruginosa (both Gram-negative), Staphylococcus aureus (Gram-positive) and Candida parapsilosis (fungus). The main components of C. zehntneri, P. emarginatus and S. brasiliensis were identified as estragole, trans-anethole, β-caryophyllene and myrcene. Among the EOs, P. emarginatus showed the highest antioxidant activity, with an IC50 of 7.36 mg/mL and a Trolox equivalent antioxidant capacity of 3748 μmol/g determined by DPPH and ORAC assays, respectively. All EOs showed low activities against the bacterial strains tested, whereas the C. zehntneri oil and its main constituent estragole exhibited an appreciable antifungal activity against C. parapsilosis. 相似文献
57.
Wagner Batista dos Santos Kelly Aparecida Encarnao Amorim Anderson Dourado Galvo Fabricio Tarso Moraes Dario Batista Fortaleza Luiz Alfredo Pavanin 《Photochemistry and photobiology》2019,95(6):1306-1310
Photochemical reactions of ruthenium (II) complexes of type trans‐[Ru(NH3)4LL']2+, where L is a nitrogenous heterocyclic ligand, pyridine (py), isonicotinamide (isn), 4‐acetylpyridine (4‐acpy) or 4‐picoline (4‐pic), and L´ is a 1,2‐bis(4‐pyridyl)ethane (bpa) ligand, were studied with the purpose of evaluating the ligand exchange when, in solution, the complexes are irradiated at the wavelengths of 365, 436, 480 and 519 nm. The study revealed that at lower wavelengths, a labilization process is observed for py and 4‐pic ligands, even at low quantum yields, indicating the dependence of the photolabeling process on the wavelength. The study also reveals that for the filters of greater wavelength, the processes of photolabilization do not occur for any of the studied complexes. The study also shows that there are no photolization processes for the complexes obtained with the isn and 4‐acpy ligands, and it is therefore possible to classify them as nonreactive. 相似文献
58.
59.
Fabricio Augusto Barone Rangel Giancarlo Thales Camilo da Silva José Abdalla Helay?l-Neto 《Brazilian Journal of Physics》2012,42(1-2):120-124
We present an alternative approach to justify the electric charge quantization by means of non-global electromagnetic potentials. We adopt a non-global potential whose singularity does not goes over to infinity and can be entirely embedded into an arbitrarily small closed ball. 相似文献
60.
João Miguel de Faria Jr. Fabricio Machado Enrique Luis Lima José Carlos Pinto 《大分子反应工程》2010,4(1):11-24
It is demonstrated that during suspension polymerizations it is possible to monitor morphological characteristics of PVC resins such as bulk density, cold plasticizer absorption and average particle diameter in‐line and in real time using NIR spectroscopy. NIR spectra are obtained at different experimental conditions, showing that the spectra are sensitive to changes in the PVC properties. Standard mathematical procedures (partial least squares regression) are used to build empirical models and correlate the morphological properties with the obtained NIR spectra, allowing for monitoring of the PVC morphology in‐line and in real time.