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排序方式: 共有221条查询结果,搜索用时 390 毫秒
211.
Osellame R Chiodo N della Valle G Taccheo S Ramponi R Cerullo G Killi A Morgner U Lederer M Kopf D 《Optics letters》2004,29(16):1900-1902
Optical waveguide writing is demonstrated by means of a diode-pumped cavity-dumped Yb:glass femtosecond laser oscillator with a pulse energy of 270 nJ at a 166-kHz repetition rate. Waveguides realized on an Er:Yb-doped phosphate glass are almost perfectly mode matched to standard single-mode fibers at 1.55 microm and show a 1.2-dB net gain in a standard telecommunications amplifier setup. Waveguide writing with a compact femtosecond laser oscillator is an important step toward introducing this technique into an industrial context. 相似文献
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213.
The church of San Pietro in Valle in Fano is with good reason considered one of the outstanding examples of baroque art in Central Italy. Currently the church is in a serious degradation status. For this reason, and in order to devise a correct conservative restoration project, a scientific study has been carried out, aimed at characterizing mortars used for the application of marble decorations and the different degradation products occurring in the church (i.e. pulverizations, encrustations, salt efflorescences, and condensation water). In the following, results obtained analyzing the different sample typologies by optical microscopy, X-ray diffraction, electron scanning microscopy with energy-dispersion micro-analytical system, ion chromatography, and head-space solid phase microextraction-gas chromatography-mass spectrometry will be reported. 相似文献
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215.
Letizia Modeo Giovanna Rosati Ilaria Andreoli Simone Gabrielli Franco Verni Giulio Petroni 《Proceedings of the Japan Academy. Series B, Physical and biological sciences》2006,82(9):359-374
In the present paper we redescribe the ciliate Chattonidium setense Villeneuve 1937 combining morphological observations (live, stained, scanning, and transmission electron microscope) with behavioral notes and molecular data. Ultrastructural analysis revealed remarkable similarities between Chattonidium and representative members of the class Heterotrichea in cortical structure and cytoplasmic organization. The most similar genus for these aspects appears to be Condylostoma. To verify this relatedness, 18S rRNA genes from Chattonidium and from one Condylostoma species were sequenced. Phylogenetic analysis indicates Chattonidium belongs to the class Heterotrichea defined according to the modern taxonomy, and confirms its relatedness with Condylostoma already hypothesized by Villeneuve-Brachon (1940). The presence of the aboral cavity complex, a unique feature never described in other ciliates, and its peculiar organization revealed by ultrastructural analysis fully justify, in our opinion, the maintenance of Chattonidium in the separate family Chattonidiidae, established by Villeneuve-Brachon in 1940. 相似文献
216.
Letizia Pontoriero Marco Schiavina Dr. Maria Grazia Murrali Prof. Roberta Pierattelli Prof. Isabella C. Felli 《Angewandte Chemie (Weinheim an der Bergstrasse, Germany)》2020,132(42):18696-18704
Many properties of intrinsically disordered proteins (IDPs), or protein regions (IDRs), are modulated by the nature of amino acid side chains as well as by local solvent exposure. We propose a set of exclusively heteronuclear NMR experiments to investigate these features in different experimental conditions that are relevant for physiological function. The proposed approach is generally applicable to many IDPs/IDRs whose assignment is available in the Biological Magnetic Resonance Bank (BMRB) to investigate how their properties are modulated by different, physiologically relevant conditions. The experiments, tested on α-synuclein, are then used to investigate how α-synuclein senses Ca2+ concentration jumps associated with the transmission of nerve signals. Novel modules in the primary sequence of α-synuclein optimized for calcium sensing in highly flexible, disordered protein segments are identified. 相似文献
217.
Alessandro Chiodo Hiroshi Iritani Yongbin Ruan 《Publications Mathématiques de L'IHéS》2014,119(1):127-216
We show that the Gromov-Witten theory of Calabi-Yau hypersurfaces matches, in genus zero and after an analytic continuation, the quantum singularity theory (FJRW theory) recently introduced by Fan, Jarvis and Ruan following a proposal of Witten. Moreover, on both sides, we highlight two remarkable integral local systems arising from the common formalism of $\widehat {\Gamma }$ -integral structures applied to the derived category of the hypersurface {W=0} and to the category of graded matrix factorizations of W. In this setup, we prove that the analytic continuation matches Orlov equivalence between the two above categories. 相似文献
218.
In the last years several authors have used Lubich convolution quadrature formulas to discretize space-time boundary integral
equations representing time dependent problems. These rules have the fundamental property of not using explicitly the expression
of the kernel of the integral equation they are applied to, which is instead replaced by that of its Laplace transform, usually
given by a simple analytic function. In this paper, a review of these rules, which includes their main properties, several
new remarks and some conjectures, will be presented when they are applied to the heat and wave space-time boundary integral
equation formulations. The construction and behavior of the corresponding coefficients are analyzed and tested numerically.
When the quadrature is defined by a BDF method, a new approach for the representation of its coefficients is presented. 相似文献
219.
Lepore L Gualtieri MJ Malafronte N Cotugno R Dal Piaz F Ambrosio L De Falco S De Tommasi N 《Natural product communications》2011,6(7):943-946
Angiogenesis is a crucial step in many pathological conditions like cancer, inflammation and metastasis formation; on these basis the search for antiangiogenic agents has widened. In order to identify new compounds able to interfere in the Vascular Endothelial Growth Factor Receptor-1 (VEGFR-1, also known as Flt-1) recognition by VEGFs family members, we screened Calycolpus moritzianus (O. Berg) Burret leaves extracts by a competitive ELISA-based assay. MeOH and CHCl3 extracts and several their fractions demonstrated to be able to prevent VEGF or PlGF interaction with Flt-1, with an inhibition about 50% at concentration of 100 microg/mL. Phytochemical and pharmacological investigation of the active fractions led to the isolation of flavonoids, and terpenes. 相似文献
220.