Search results for "Roth"
showing 10 items of 806 documents
Novel metal–organic frameworks based on 5-bromonicotinic acid: Multifunctional materials with H2 purification capabilities
2012
Two new metal–organic frameworks based on 5-bromonicotinic acid complexes [Cd(5-BrNic)2]n (1) and [Co(5-BrNic)2(H2O)]n (2) have been synthesized by hydrothermal reactions of this ligand with cadmium and cobalt metallic(II) salts in the presence of water. Compound 1 displays intense photoluminescence properties in the solid state at room temperature, while 2 exhibits an antiferromagnetic interaction between Co(II) ions with a J value of −4.1 cm−1. Experimental studies, backed up by Monte Carlo simulations about adsorption, pore size distribution and accessible surface area reveal the capability of 2 for H2 purification applications.
Enhanced UV emission from ZnO nanoflowers synthesized by the hydrothermal process
2012
ZnO nanoflowers were synthesized by the hydrothermal process at an optimized growth temperature of 200 °C and a growth/reaction time of 3 h. As-prepared ZnO nanoflowers were characterized by x-ray diffraction, scanning electron microscopy, UV–visible and Raman spectroscopy. X-ray diffraction and Raman studies reveal that the as-synthesized flower-like ZnO nanostructures are highly crystalline with a hexagonal wurtzite phase preferentially oriented along the plane. The average length (234–347 nm) and diameter (77–106 nm) of the nanorods constituting the flower-like structure are estimated using scanning electron microscopy studies. The band gap of ZnO nanoflowers is estimated as 3.23 eV, the…
Efficacy of Selected Electrical Therapies on Chronic Low Back Pain: A Comparative Clinical Pilot Study
2017
Background: In the currently available research publications on electrical therapy of low back pain, generally no control groups or detailed randomization were used, and such studies were often conducted with relatively small groups of patients, based solely on subjective questionnaires and pain assessment scales (lacking measurement methods to objectify the therapeutic progress). The available literature also lacks a comprehensive and large-scale clinical study. The purpose of this study was to assess the effects of treating low back pain using selected electrotherapy methods. The study assesses the influence of individual electrotherapeutic treatments on reduction of pain, improvement of …
On the renormalization of ultraviolet divergences in the inflationary angular power spectrum
2015
We revise the role of ultraviolet divergences of cosmological observables and the corresponding renormalization from a space-time perspective. We employ the two-point function of primordial perturbations generated during inflation to derive an analytic expression for the multipole coefficients Cl in the Sachs-Wolfe regime. We analyzethe ultraviolet behaviorand stress the fact that the standard result in the literature is equivalent to a renormalization of the two-point function at zeroth adiabatic order. We also argue that renormalization at second adiabatic order seems to be more appropriate from a physical point of view. This may change significantly the predictions for Cl, while maintain…
Interdisciplinarité et interculturalité à partir de deux romans : Les Nuits de Strasbourg d’Assia Djebar et Le Village de l’Allemand ou le journal de…
2021
My presentation focuses on interdisciplinarity and interculturality on the basis of two novels, "Les Nuits de Strasbourg" by Assia Djebar and "Le Village de l'Allemand ou le journal des frères Schiller" by Boualem Sansal. Firstly, I reflect in a general way on interdisciplinarity and its affinity with interculturality before addressing these issues in my corpus and in my work. Secondly, I look at some theories, interdisciplinary and sometimes intercultural, that help me to study my corpus in a harmonious way, which I illustrate with concrete analyses referring to the thought of Édouard Glissant. Finally, I propose interdisciplinary developments of an intercultural approach, that of Michael …
Un contrato inédito de Juan de Juanes. El retablo de la Cofradía de la Sangre de Cristo de Valencia (1539)
2012
This article is based on an unpublished contract signed in 1539 by Vicente and Juan Macip for an altarpiece for the Valencian Brotherhood of the Blood of Christ. The agreement stipulates that Juan, later known as Juan de Juanes, had to paint the scenes. Thus the document reinforces the hypothesis that Juan Macip was the most important painter in the Macip workshop during the 1530’s. It also fills a documental void in between the completion of the Silversmith’s Guild altarpiece (1534-1539) and the contract for the Fuente la Higuera altarpiece (1548). This study also verifies the popularity of the iconography of the seven sheddings of the Blood of Christ and processions of disciplinants.<b…
Violence and the Peasant Elite in Lower Satakunta (1550–1680)
2016
“The lengthy quarrels over inheritance hint that these people had fiery tempers”, wrote Mauno Jokipii in his pioneering article on the history of the Lavila family—one of the prominent families of freeholders in Lower Satakunta.1 In our study on the women from that same family, Virpi Nissila and I have encountered about 100 court cases from the 1620 to the 1650s, in which six women from two generations have been present. The most prominent of them is Anna Martensdotter who appeared in court 28 times in the four years for which we have the court minutes still intact. These records tell of her offensive behaviour: neighbours complaining about her physical violence, insults, appropriations, an…
Selective propane oxidation over MoVSbO catalysts. On the preparation, characterization and catalytic behavior of M1 phase
2009
Nb-free (SbO)(2)M(20)O(56) catalysts (M = Mo, V) presenting pure M1 phase have been prepared by a post-synthesis treatment with hydrogen peroxide of a heat-treated MoVSbO mixed metal oxide catalyst previously prepared by hydrothermal method. The characterization of catalysts and their results for propane oxidation suggest that the optimization in the preparation of the M1 phase depends strongly on the washing procedure. The optimal removing of Sb species formed during post-synthesis treatment can explain the improvement in the catalytic activity; while the better selectivity to acrylic acid of the catalysts obtained by post-synthesis treatment can be explained by the elimination of M2 phase…
Hydrothermal Synthesis of ZnO Crystals from Zn(OH)2 Metastable Phases at Room to Supercritical Conditions
2014
The originality of this work is to highlight the effect of temperature and pressure on the size and morphology of hydrothermal ZnO particles from ambient to supercritical conditions (T > 374 °C and P > 221 bar) using a unique continuous one-step process. Experiments were carried out from zinc nitrate (Zn(NO3)2) and potassium hydroxide (KOH) solutions in the ranges of 1–300 bar and 30–400 °C. The as-prepared particles of ZnO (flower, ellipsoid, and sphere) and e-Zn(OH)2 (polyhedral) sized from nano to micrometers were characterized by X-ray diffraction and electronic microscopy. The wulfingite phase (e-Zn(OH)2) was detected inside some powders especially at room temperature for higher pressu…
Effect of hydrothermal time on the forming specific morphology of YPO4:Eu3+ nanoparticles for dedicated luminescent applications as optical markers
2023
A way to control the desired shape and microstructure of YPO4:Eu3+ nanoparticles through the precipitation method followed by a hydrothermal treatment is reported. This method is useful for achieving very high control over the YPO4:Eu3+ formation process with the selection of appropriate synthesis parameters. In detail, the autoclave processing time allows control of the shape and size of nano-needle-shaped particles independently in both directions, as confirmed by X-ray powder diffraction, FT-IR Spectroscopy and Electron Transmission Microscopy. In order to analyse the effect of the nanoparticles’ surroundings on the excitation and relaxation processes of luminescent ions, Eu3+ ion was us…