Search results for "blue"
showing 10 items of 487 documents
Global Frequency and Geographical Distribution of Nighttime Streamer Corona Discharges (BLUEs) in Thunderclouds
2021
This is an open access article under the terms of the Creative Commons Attribution-NonCommercial License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited and is not used for commercial purposes.
Exciton interactions in self-organised bacteriochlorophyll a - aggregates
2002
Exciton interactions of self-organised bacteriochlorophyll a - aggregates in non-polar solution linked via water and dioxane have been studied. Absorption and CD spectra of the aggregates show large red shifts typical of J-aggregates. Femtosecond excitation of the Qy band of the aggregates is followed by wavelength dependent non-exponential picosecond relaxation and anisotropy decay takes place in subpicosecond time scale. To explain these observations exciton theory and semi-empirical MO/CI calculations, that constitute the basis of the CIEM-approach developed by Linnanto et al. (J. Phys. Chem. B, 1999, 103B, 8739) was used. Structural models of aggregates were created by using the molecul…
With God and Guitars: Popular Music, Socialism, and the Church in East Germany
2017
AbstractIn the socialist German Democratic Republic (GDR), the Church entered into a long-term, complex and productive symbiosis with popular music. Beginning in the 1950s, reform-minded pastors opened their doors to jazz, and, later, almost the entire spectrum of popular music could be found in their churches: from pop hits, beat, rock, blues to singer/songwriters and punk. The interplay between the Church and popular music gave rise to a highly unique communicative space, a counterpart to the rigidly organized public realm. Here, political dissidents took refuge from a repressive system and were free to examine their society critically. This political force infused the alliance of the Chu…
Urban Development and Social Change in Qatar: The Qatar National Vision 2030 and the 2022 FIFA World Cup
2012
On 2 December 2010, Qatar, the exotic outsider, surprisingly won the bid for the 2022 FIFA World Cup, thereby becoming the first Middle Eastern country chosen to host the global festival of this ‘royal football league’. Qataris have high hopes for the tournament, and ambitious aims for their country's development in preparation for 2022 and beyond. Since the rise to power of the current Amir, Shaikh Hamad bin Khalifa Al Thani, in 1995, he has gradually introduced neoliberal policies in an attempt to build a knowledge-based economy. These developments are taking place in the context of Qatar's National Vision 2030, the blueprint for Qatar's economic, social, human, and environmental developm…
Oppressive Faces of Whiteness in Walter Mosley’s Devil in a Blue Dress
2018
Walter Mosley’s Devil in a Blue Dress contributes significantly to the literary debate on the definition of whiteness. The socio-historical construction of whiteness emerging from the novel is amplified by white imagery dovetailing with the claims made about white people directly. For the African American first person narrator, Easy Rawlins, living in post-World War II Los Angeles, whiteness mostly spells terror. The oppressive faces of whiteness consist in the following trajectories: property relations, economic exploitation, labour relations, the legal system, different miens of oppressive white masculinity denigrating blackness, spatial dynamics of post-World War II Los Angeles and the w…
Synchrotron Radiation-Based Micro-XANES and Micro-XRF Study of Unsuccessfully Produced Egyptian Blue from the Late Hellenistic Production Site of Kos…
2021
International audience; This paper examines the production technology of Egyptian blue, an ancient artificial pigment, through the investigation of an unsuccessfully produced pellet derived from the Hellenistic production site of Kos (Dodecanese, Greece). This heterogeneous material was investigated by a combination of laboratory and synchrotron radiation-based (SR) techniques: scanning electron microscopy coupled with energy-dispersive Xray spectrometry, micro-Raman spectroscopy, high-resolution SR micro-X-ray fluorescence spectroscopy, and SR micro-X-ray absorption near-edge structure spectroscopy (XANES), at the ID21 beamline of the European Synchrotron Radiation Facility. Principal comp…
On/Off Photoswitching in a Cyanide-Bridged {Fe2Co2} Magnetic Molecular Square
2013
International audience; A repeatable bidirectional paramagnetic ↔ diamagnetic photomagnetic effect has been observed in the cyanide-bridged Fe-Co square complex {[Fe{B(pz)(4)}(CN)(3)](2)[Co(bik)(2)](2)}(ClO(4))(2)*3H(2)O [B(pz)(4) = tetrapyrazolylborate, bik = bis(1-methylimidazol-2-yl)ketone]. Magnetic measurements and low-temperature single-crystal X-ray diffraction experiments have shown that a complete electron transfer from the diamagnetic Fe(II)-Co(III) state to the paramagnetic Fe(III)-Co(II) metastable state is induced by 808 nm laser light irradiation, whereas the diamagnetic state is recovered in an almost quantitative yield under irradiation at 532 nm.
Cutting efficiency of heat-treated nickel-titanium single-file systems at different incidence angles.
2020
Cutting efficiency of Reciproc R25 (REC) and Reciproc blue R25 (REB) at different inclinations was evaluated. Sixty new files were tested at 90°, 70° and 45° of inclination in relation to the sample (n = 10), using a customised machine. All files were activated in reciprocation against standardised gypsum blocks for 120 s. Cutting efficiency was determined by measuring the block weight loss with an analytical balance and measuring the length of the block surface cut using a digital calliper. Data were statistically analysed (two-way ANOVA, Bonferroni t-test) with the significance level set at P < 0.05. There was no difference for REC among the tested angles. REB had no statistical differenc…
Charged Bis-Cyclometalated Iridium(III) Complexes with Carbene-Based Ancillary Ligands
2013
Charged cydometalated (CN) iridium(III) complexes with carbene-based ancillary ligands are a promising family of deep-blue phosphorescent compounds. Their emission properties are controlled primarily by the main CN ligands, in contrast to the classical design of charged complexes where NN ancillary ligands with low-energy pi* orbitals, such as 2,2'-bipyridine, are generally used for this purpose. Herein we report two series of charged iridium complexes with various carbene-based ancillary ligands. In the first series the CAN ligand is 2-phenylpyridine, whereas in the second one it is 2-(2,4-difluorophenyl)-pyridine. One biscarbene (:CC:) and four different pyridine carbene (NC:) chelators a…
Upconversion nanoparticles with a strong acid-resistant capping
2016
Water-dispersible upconversion nanoparticles (β-NaYF:Yb,Er, UCNP) coated with a thin shell of a biocompatible copolymer comprising 2-hydroxyethylmethacrylate (HEMA) and 2-acrylamido-2-methyl-1-propanesulphonsulphonic acid (AMPS), which we will term COP, have been prepared by multidentate grafting. This capping is remarkably resistant to strong acidic conditions as low as pH 2. The additional functionality of the smart UCNP@COP nanosystem has been proved by its association to a well-known photosensitizer (namely, methylene blue, MB). The green-to-red emission ratio of the UC@COP@MB nanohybrid exhibits excellent linear dependence in the 7 to 2 pH range as a consequence of the release of the d…