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131.
Dr. Carmen C. Piras Prof. David K. Smith 《Chemistry (Weinheim an der Bergstrasse, Germany)》2021,27(58):14527-14534
Hybrid gel beads based on combining a low-molecular-weight gelator (LMWG) with a polymer gelator (PG) demonstrate an enhanced ability to self-propel in water, with the LMWG playing an active role. Hybrid gel beads were loaded with ethanol and shown to move in water owing to the Marangoni effect changes in surface tension caused by the expulsion of ethanol – smaller beads move farther and faster than larger beads. Flat shapes of the hybrid gel were cut using a “stamp” – circles moved the furthest, whereas stars showed more rotation on their own axes. Comparing hybrid LMWG/PG gel beads with PG-only beads demonstrated that the LMWG speeds up the beads, enhancing the rate of self-propulsion. Self-assembly of the LMWG into a “solid-like” network prevents its leaching from the gel. The LMWG also retains its own unique function – specifically, remediating methylene blue pollutant dye from basic water as a result of noncovalent interactions. The mobile hybrid beads accumulate this dye more effectively than PG-only beads. Self-propelling gel beads have potential applications in removal/delivery of active agents in environmental or biological settings. The ability of self-assembling LMWGs to enhance mobility and control removal/delivery suggests that adding them to self-propelling systems can add significant value. 相似文献
132.
Esperanza Menéndez Luis Vega Carmen Andrade 《Journal of Thermal Analysis and Calorimetry》2012,110(1):203-209
In field structures affected by fire, the temperature progress through the material. The progression of temperature in the concrete material can be determined by simultaneous differential thermal analysis and thermogravimetry. Also, the analysis of the behaviour of concrete in real concrete, by different techniques, permits the corroboration of the hypothesis of cover calculation. In this study, the analysis of concrete exposed to a very severe fire is studied in order to corroborate the calculus hypothesis and to determine the progression of the temperature inside the affected structure. In this study, the potentiality of the thermal instrumental techniques is studied to determine the situation of the concrete exposed to fire. These results can be used to calculate the residual strength of the concrete structural elements. Also, other auxiliary techniques are used to have some supplementary information about the situation of the concrete exposed to fire. The results are based in concrete samples from a real fire in the Windsor Building in Madrid. The Windsor Building in Madrid was project in 1974 and built between 1975 and 1979. This building was severely damaged by a serious fire on the 12th of February 2005, which lasted approximately 12?h. 相似文献
133.
134.
In the context of symmetric-definite generalized eigenvalue problems, it is often required to compute all eigenvalues contained
in a prescribed interval. For large-scale problems, the method of choice is the so-called spectrum slicing technique: a shift-and-invert
Lanczos method combined with a dynamic shift selection that sweeps the interval in a smart way. This kind of strategies were
proposed initially in the context of unrestarted Lanczos methods, back in the 1990’s. We propose variations that try to incorporate
recent developments in the field of Krylov methods, including thick restarting in the Lanczos solver and a rational Krylov
update when moving from one shift to the next. We discuss a parallel implementation in the SLEPc library and provide performance
results. 相似文献
135.
Karina Muñoz-Becerra Nery Villegas-Escobar César Zúñiga-Loyola Diego Cortés-Arriagada 《Molecular physics》2019,117(9-12):1451-1458
ABSTRACTAurones are potential candidates to be employed as fluorescent probes or as pharmacophores for biological applications. This work describes a density functional theory (DFT) and time-dependent -DFT study at the PBE0/6-31?+?G(d) level of theory to analyse the structural, electronic and photophysical properties of a series of new proposed 4′-amine-aurone derivatives in its E and Z isomeric conformations. The maximum absorption wavelength of the proposed aurones appears in the range 390???514?nm, while the most allowed emission pathways were computed in the range 493–530?nm. The bathochromic shift of these compounds with respect to the non-substituted aurone is modulated by the acceptor strength of the added 4-substituents, in addition to the ability of the substituents to localise the frontier molecular orbitals over the acceptor benzofuranone moiety without losing the tricyclic planarity, which favours the push–pull nature of these molecules. The influence of the 4-substituent is also evidenced in the Stokes shifts for the whole series; as the electron-withdrawing character of the 4-substituents enhances, higher is the polarisation of the structure resulting in higher Stokes shifts. As a result, -CF3 and -NO2 substituents were responsible of larger Stokes shifts, then compounds containing these substituents are proposed as potential fluorescence probes for useful applications in biological systems. 相似文献
136.
137.
Carro María J. Ortiz-Caraballo Carmen 《Journal of Fourier Analysis and Applications》2019,25(1):145-166
Journal of Fourier Analysis and Applications - We prove a weighted estimate for the disc multiplier, acting on radial functions, at the extreme points $$p_{-}=\frac{2n}{n+1}$$ , extending the... 相似文献
138.
The multicomponent Amine-Aldehyde-Dienophile reaction is optimized employing benzyl or 4-methoxybenzylamine. The interest of the transformation consist in the synthesis of polysubstituted cyclohex-2-enylamines. The study of the scope of this AAD process is carried out, as well as the diastereoselective version, employing commercially available chiral benzylic amines and a maleimide with the chiral information at the N-substituent. VCD spectroscopy is a very useful tool for the determination of the absolute configuration of the isolated enantiomerically enriched compounds. 相似文献
139.
Maria Jo?o Carrilho Plancha Carmen Mireya Rangel César Augusto Correia de Sequeira 《Journal of Solid State Electrochemistry》2012,16(2):665-671
The (PEO)4ZnCl2 electrolyte (PEO, polyethylene oxide) was studied in view of its potential application in a solid-state rechargeable zinc
cell. The electrochemical stability window was established, and decomposition voltage values between 3.19 (20 °C) and 1.44 V
(150 °C) were estimated. Cyclic voltammetry studies using a Pt/(PEO)4ZnCl2/Pt cell indicated reversibility of the Zn2+/Zn couple at the electrode/electrolyte interface. Laboratory cells Zn(−)/(PEO)4ZnCl2/Nb2O5(+) were assembled and studied at 55 °C, under various discharge current densities. Results of cell discharge profiles, capacity
values, charge–discharge cycles and cell stabilities are reported. 相似文献
140.
Conjugated addition of alcohols to 9-hydroxy-and 9-methoxy-1, 4-anthraquinone, in the presence of a strong acid and an oxidant, affords the 2-alkoxy- and 3-alkoxy-substituted regioisomer, respectively. 相似文献