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排序方式: 共有667条查询结果,搜索用时 31 毫秒
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Dr. Maria A. Antunes Joana T. Coutinho Dr. Isabel C. Santos Dr. Joaquim Marçalo Prof. Manuel Almeida José J. Baldoví Dr. Laura C. J. Pereira Dr. Alejandro Gaita‐Ariño Prof. Eugenio Coronado 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(49):17817-17826
A tetravalent uranium compound with a radical azobenzene ligand, namely, [{(SiMe2NPh)3‐tacn}UIV(η2‐N2Ph2.)] ( 2 ), was obtained by one‐electron reduction of azobenzene by the trivalent uranium compound [UIII{(SiMe2NPh)3‐tacn}] ( 1 ). Compound 2 was characterized by single‐crystal X‐ray diffraction and 1H NMR, IR, and UV/Vis/NIR spectroscopy. The magnetic properties of 2 and precursor 1 were studied by static magnetization and ac susceptibility measurements, which for the former revealed single‐molecule magnet behaviour for the first time in a mononuclear UIV compound, whereas trivalent uranium compound 1 does not exhibit slow relaxation of the magnetization at low temperatures. A first approximation to the magnetic behaviour of these compounds was attempted by combining an effective electrostatic model with a phenomenological approach using the full single‐ion Hamiltonian. 相似文献
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Some small scientific satellites can be regarded as free, multi-body, supercritical and statorless rotors. Classical rotordynamics does not cover the dynamic behaviour and the stability analysis of such rotating systems, being focused on fixed rotors. Attitude dynamics usually deals with single rigid spacecrafts, sometimes equipped with flexible appendices like solar arrays or antennas. The case of the Galileo Galilei Ground (GGG) test facility is herewith analyzed through a numerical and experimental investigation on the dynamic behaviour of a fixed multi-body fast-spinning rotor in order to validate the design approach proposed for Galileo Galilei (GG) spacecraft. 相似文献
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Corrado Di Natale Roberto Paolesse Eugenio Martinelli Rosamaria Capuano 《Analytica chimica acta》2014
The analysis of volatile compounds is an efficient method to appraise information about the chemical composition of liquids and solids. This principle is applied to several practical applications, such as food analysis where many important features (e.g. freshness) can be directly inferred from the analysis of volatile compounds. 相似文献
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Jiménez-Millán E Giner-Casares JJ Muñoz E Martín-Romero MT Camacho L 《Langmuir : the ACS journal of surfaces and colloids》2011,27(24):14888-14899
The surface active derivative of the organic dye Acridine Orange (N-10-dodecyl-acridine orange (DAO)) has been included in mixed Langmuir monolayers with stearic acid (SA). The maximum relative content on DAO for a stable mixed monolayer is a molar ratio of X(DAO) = 0.5. Brewster angle microscopy (BAM) reveals a high homogeneity at the micrometer level for the mixed monolayer in equimolar proportion (X(DAO) = 0.5), whereas the appearance of domains occurs for lower content of DAO, i.e., X(DAO) = 0.2 and 0.1. The aggregation of the DAO headgroup leads to well-defined H-aggregates at the air/water interface for those mixed monolayers with a low content of DAO. However, for the mixed monolayers enriched in DAO, e.g., X(DAO) = 0.5, the molecular crowding prevents the formation of defined supramolecular structures. Molecular organization and tilting of the DAO headgroup is quantitatively analyzed by in situ UV-visible reflection spectroscopy. The formation of H-aggregates of the DAO headgroup can be reversibly tuned with the applied surface pressure. A molecular mechanism for the conformational rearrangement of the DAO molecule is proposed using RM1 quantum semiempirical calculations. 相似文献
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Rodrigues JA Oliveira RP Ratusznei SM Zaiat M Foresti E 《Applied biochemistry and biotechnology》2011,163(1):127-142
A study was performed regarding the effect of the relation between fill time, volume treated per cycle, and influent concentration
at different applied organic loadings on the stability and efficiency of an anaerobic sequencing batch reactor containing
immobilized biomass on polyurethane foam with recirculation of the liquid phase (AnSBBR) applied to the treatment of wastewater
from a personal care industry. Total cycle length of the reactor was 8 h (480 min). Fill times were 10 min in the batch operation,
4 h in the fed-batch operation, and a 10-min batch followed by a 4-h fed batch in the mixed operation. Settling time was not
necessary since the biomass was immobilized and decant time was 10 min. Volume of liquid medium in the reactor was 2.5 L,
whereas volume treated per cycle ranged from 0.88 to 2.5 L in accordance with fill time. Influent concentration varied from
300 to 1,425 mg COD/L, resulting in an applied volumetric organic load of 0.9 and 1.5 g COD/L.d. Recirculation flow rate was
20 L/h, and the reactor was maintained at 30 °C. Values of organic matter removal efficiency of filtered effluent samples
were below 71% in the batch operations and above 74% in the operations of fed batch followed by batch. Feeding wastewater
during part of the operational cycle was beneficial to the system, as it resulted in indirect control over the conversion
of substrate into intermediates that would negatively interfere with the biochemical reactions regarding the degradation of
organic matter. As a result, the average substrate consumption increased, leading to higher organic removal efficiencies in
the fed-batch operations. 相似文献