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71.
72.
The IR and Raman spectra of the oxyapatite Ca8La2(VO4)6O2 has been measured and discussed in comparison with those of related species. Data for Ca8La2(PO4)6O2 and for a solid solution of composition Ca8La2(PO4)6O2 are also reported. 相似文献
73.
Benito Alcaide Gerardo Escobar JoséL. González-Simó Carmen López-Mardomingo Rafael Pérez-Ossorio Joaquin Plumet 《Tetrahedron letters》1982,23(19):2033-2036
Total stereoselectivity is observed in the sodium borohydride reduction of α-aminodeoxybenzoins and their hydrochlorides in various hydroxylic solvents. RS - SR isomer (erythro) was the only aminoalcohol obtained. 相似文献
74.
Crystallographic data for the oxoapatites of general formula Ca8
Ln
2(PO4)6O2 withLn=La, Pr-Ho) have been obtained from X-ray powder data. The vibrational spectra, which are also discussed, allow to make a proposal about the location of the lanthanide cations present in these lattices. 相似文献
75.
Fabiola Angulo Gerard Olivar Gustavo A. Osorio Carlos M. Escobar Jocirei D. Ferreira Johan M. Redondo 《Communications in Nonlinear Science & Numerical Simulation》2012,17(12):4683-4689
Non-smooth systems (namely piecewise-smooth systems) have received much attention in the last decade. Many contributions in this area show that theory and applications (to electronic circuits, mechanical systems, …) are relevant to problems in science and engineering. Specially, new bifurcations have been reported in the literature, and this was the topic of this minisymposium. Thus both bifurcation theory and its applications were included. Several contributions from different fields show that non-smooth bifurcations are a hot topic in research. Thus in this paper the reader can find contributions from electronics, energy markets and population dynamics. Also, a carefully-written specific algebraic software tool is presented. 相似文献
76.
de Escobar Cícero Coelho Lansarin Marla Azário Santos João Henrique Zimnoch dos Brandestini Milena Duarte 《Journal of Sol-Gel Science and Technology》2018,88(1):220-226
Journal of Sol-Gel Science and Technology - In this work, a ZnO-based molecularly imprinted photocatalyst (MIP) bearing acid Lewis sites (Al) was evaluated for photocatalytic oxidation of glycerol.... 相似文献
77.
Reducing inconsistency measured by the geometric consistency index in the analytic hierarchy process
Juan Aguarón María Teresa Escobar José María Moreno-Jiménez 《European Journal of Operational Research》2021,288(2):576-583
This paper presents a theoretical framework and a procedure for revising the judgements and improving the inconsistency of an Analytic Hierarchy Process (AHP) pairwise comparison matrix when the Row Geometric Mean (RGM) is used as the prioritisation procedure and the Geometric Consistency Index (GCI) is the inconsistency measure. Inconsistency is improved by slightly modifying the judgements that further reduce the GCI. Both the judgements and the derived priority vector will be close to the initial values. A simulation study is utilised to analyse the performance of the algorithm. The proposed framework allows the specification of the procedure to particular interests. A numerical example illustrates the proposed procedure. 相似文献
78.
Abouzaid E Arenton M Barker AR Bellantoni L Blucher E Bock GJ Cheu E Coleman R Corcoran MD Cox B Erwin AR Escobar CO Glazov A Golossanov A Gomes RA Gouffon P Hsiung YB Jensen DA Kessler R Kotera K Ledovskoy A McBride PL Monnier E Nguyen H Niclasen R Phillips DG Ping H Ramberg EJ Ray RE Ronquest M Santos E Slater W Smith D Solomey N Swallow EC Toale PA Tschirhart R Velissaris C Wah YW Wang J White HB Whitmore J Wilking MJ Winston R Worcester ET Worcester M Yamanaka T Zimmerman ED 《Physical review letters》2011,107(20):201803
The KTeV E799 experiment has conducted a search for the rare decays, K(L)→π(0)π(0)μ(+)μ(-) and K(L)→π(0)π(0)X(0)→π(0)π(0)μ(+)μ(-), where the X(0) is a possible new neutral boson that was reported by the HyperCP experiment with a mass of (214.3 ± 0.5) MeV/c(2). We find no evidence for either decay. We obtain upper limits of Br(K(L)→π(0)π(0)X(0)→π(0)π(0)μ(+)μ(-)) < 1.0 × 10(-10) and Br(K(L)→π(0)π(0)μ(+)μ(-)) < 9.2 × 10(-11) at the 90% confidence level. This result rules out the pseudoscalar X(0) as an explanation of the HyperCP result under the scenario that the dsX(0) coupling is completely real. 相似文献
79.
Cícero Coelho de Escobar Mauro Henrique Dartora Leandra Franciscato Campo Claudio Radtke Julia M. Bayne Ian S. Butler Rafael M. Lattuada João Henrique Zimnoch dos Santos 《Journal of Sol-Gel Science and Technology》2014,72(2):260-272
A series of silica xerogels having rhodamine B (RhB) as a template and Ti centers were synthesized by distinct sol–gel routes, namely, acid-catalyzed, base-catalyzed, acid-catalyzed with base-catalyzed (two steps) hydrolytic routes and a FeCl3-catalyzed non-hydrolytic route. The interaction of RhB with the prepared silica matrix was investigated by Fourier transform infrared spectroscopy, attenuated total reflectance, diffuse reflectance spectroscopy in the ultraviolet–visible region, Raman spectroscopy, mass spectrometry, X-ray photoelectron spectroscopy (XPS), photoluminescence (PL) and confocal microscopy. Raman spectroscopy suggested the presence of Ti–O and Si–O–Ti moieties within the silica matrix. Infrared band shifts provided insight into potential interaction sites. Taking into account the results from ART, XPS, PL and confocal microscopy, encapsulation of RhB preferentially occurs inside the silica network for acid 1, basic and two-steps routes, and the presence of Ti occurs on the surface of the silica occurs for acid 2, basic and two-steps routes. Also, we have shown that although the structural characteristics of the encapsulated and extracted systems are affected by the route, the molecular structure is conserved during and after the encapsulation process. 相似文献
80.
Structural and Vibrational Characterization of the Chromophore Binding Site of Bacterial Phytochrome Agp1
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Aref Takiden Francisco Velazquez‐Escobar Jovan Dragelj Anna Lena Woelke Ernst‐Walter Knapp Patrick Piwowarski Franz Bart Peter Hildebrandt Maria Andrea Mroginski 《Photochemistry and photobiology》2017,93(3):713-723
Agp1 is a prototypical bacterial phytochrome from Agrobacterium fabrum harboring a biliverdin cofactor which reversibly photoconverts between a red‐light‐absorbing (Pr) and a far‐red‐light‐absorbing (Pfr) states. The reaction mechanism involves the isomerization of the bilin‐chromophore followed by large structural changes of the protein matrix that are coupled to protonation dynamics at the chromophore binding site. Histidines His250 and His280 participate in this process. Although the three‐dimensional structure of Agp1 has been solved at high resolution, the precise position of hydrogen atoms and protonation pattern in the chromophore binding pocket has not been investigated yet. Here, we present protonated structure models of Agp1 in the Pr state involving appropriately placed hydrogen atoms that were generated by hybrid quantum mechanics/molecular mechanics‐ and electrostatic calculations and validated against experimental structural‐ and spectroscopic data. Although the effect of histidine protonation on the vibrational spectra is weak, our results favor charge neutral H250 and H280 both protonated at Nε. However, a neutral H250 with a proton at Nε and a cationic H280 may also be possible. Furthermore, the present QM/MM calculations of IR and Raman spectra of Agp1 containing isotope‐labeled BV provide a detailed vibrational assignment of the biliverdin modes in the fingerprint region. 相似文献