Search results for "Zen"
showing 10 items of 3479 documents
Reversible Modulation of Elasticity in Fluoroazobenzene-Containing Hydrogels Using Green and Blue Light.
2017
Hydrogels are soft materials that have found multiple applications in biomedicine and represent a good platform for the introduction of molecular switches and synthetic machines into macromolecular networks. Tuning their mechanical properties reversibly with light is appealing for a variety of advanced applications and has been demonstrated in the past; however, their activation typically requires the use of UV light, which displays several drawbacks related to its damaging character and limited penetration in tissues and materials. This study circumvents this limitation by introducing all-visible ortho-fluoroazobenzene switches into a hydrophilic network, which, as a result, can be activat…
Localized Liquid Secretion from a Photopatterned Liquid-Crystal Polymer Skin
2020
Liquid-releasing artificial skins are made from films made of a smectic liquid-crystal polymer network (LCN) photopolymerized in the presence of a photoactive azobenzene chromophore and a liquid-crystal porogen. The nonreactive porogen phase separates during the polymerization process, and the polymer forms a spongy polymer network filled with liquid. The liquid is excreted from the film when exposed to UV light upon conversion of trans-azobenzene to its cis isomer. Here, localized liquid secretion at preset positions at the polymer film is described. The design principle is based on creating a hybrid molecular architecture with both smectic and nonordered isotropic alignments in a continuo…
Modular approach to obtaining organic glasses from low-molecular weight dyes using 1,1,1-triphenylpentane auxiliary groups: Nonlinear optical propert…
2013
Abstract A new modular synthetic approach to obtain organic glasses from low-molecular weight azobenzenes and stilbenes has been accomplished using 1,1,1-triphenylpentane crystallization preventing auxiliary groups. Six new structures show excellent solubility in non-polar solvents and thin films with good optical qualities have been obtained using a spin-coating technique. The glass transition temperatures of the new amorphous materials were in the range of 73–108 °C. The nonlinear optical activity in thin amorphous films was measured after a corona poling procedure.
First results of cavity ring down signals from exhaled air
2017
In this paper we report first results from the developed cavity ring-down spectrometer for application in human breath analysis for the diagnostics of diabetes and later for early detection of lung cancer. Our cavity ring-down spectrometer works in UV region with pulsed Nd:YAG laser at 266 nm wavelength. First experiments allow us to determine acetone and benzene at the level bellow ppm. In our experiment, first results from breath samples from volunteers after doing different activities were collected and examined. Influence of the smoking on the breath signals also was examined.
Hyperpolarization of cis ‐ 15 N 2 ‐Azobenzene by Parahydrogen at Ultralow Magnetic Fields**
2021
The development of nuclear spins hyperpolarization, and the search for molecules that can be efficiently hyperpolarized is an active area in nuclear magnetic resonance. In this work we present a detailed study of SABRE SHEATH (signal amplification by reversible exchange in shield enabled alignment transfer to heteronuclei) experiments on 15 N2 -azobenzene. In SABRE SHEATH experiments the nuclear spins of the target are hyperpolarized through transfer of spin polarization from parahydrogen at ultralow fields during a reversible chemical process. Azobenzene exists in two isomers, trans and cis. We show that all nuclear spins in cis-azobenzene can be efficiently hyperpolarized by SABRE at suit…
Effect of Soil Moisture on the Angular Variation of Thermal Infrared Emissivity of Inorganic Soils
2014
Emissivity is influenced by different factors. This study deals with the effect of the soil moisture (SM) content on the zenithal (θ) variation of ratio-to-nadir emissivity (εr), for a wide variety of inorganic bare soils. To retrieve εr, a goniometer assembly was used, together with two identical CIMEL Electronique CE312-2 radiometers working at six spectral bands within 7.7-14.3 μm, performing simultaneous radiance measurements at different combinations of zenith and azimuth angles. The results showed that the effect of SM upon εr(θ) is different depending on the spectral range and textural composition of the sample. Sandy soils showed a decrease of εr(θ) from nadir up to 0.132 for θ ≥ 40…
Relaxation of photogenerated carriers in P3HT:PCBM organic blends.
2009
Relaxing in the sunlight. Long time-transient decays of photogenerated carriers in P3HT:PCBM blends for organic solar cells are interpreted in terms of the relaxation of hole carriers in a broad density of states. The after-pulse time-resolved microwave conductivity (TRMC) decays observed in P3HT:PCBM blends display a dependence on time close to t−β, independent of excitation intensity, in the 10 ns–1 μs range. This is explained in terms of the relaxation of carriers in a Gaussian density of states (DOS). The model is based on a demarcation level that moves with time by thermal release and retrapping of initially trapped carriers. The model shows that when the disorder is large the after-pu…
Solution processable phosphorescent dendrimers based on cyclic phosphazenes for use in organic light emitting diodes (OLEDs)
2008
A novel solution processable phosphorescent dendrimer based on cyclic phosphazene (CP) cores has been prepared and used as emissive layers in simple OLED architectures, providing efficiencies of 24.0 cd A^-1 and 16.7 lm W^-1. Bolink, Henk, Henk.Bolink@uv.es ; Garcia Santamaria, Sonsoles Amor, Sonsoles.Garcia@uv.es
Synthesis and nonlinear optical properties of novel N,N-dihydroxyethyl-based molecular organic glasses using triaryl substitutes as amorphous phase f…
2011
In given study a new structural design of molecular NLO materials is presented where amorphous phase formation is achieved by introduction of bulky trityl and triphenylsilyl substituents. Obtained materials formed stable organic glasses with good optical quality and glass transition temperatures notably exceeding ambient. NLO activity was successfully measured in samples that underwent corona discharge poling. The comparison of both enhancer groups revealed, that trityl group increases thermal sustainability of material, while triphenylsilyl group better promotes formation and stability of amorphous phase.
Functionalized planar Bragg grating sensor for the detection of BTX in solvent vapor
2012
We report on an optical planar Bragg grating evanescent wave refractive index sensor functionalized by a simple method against aromatic hydrocarbons such as benzene, toluene and xylene (BTX) in solvent vapor. To functionalize the sensor against BTX, substituted cyclodextrins are applied to the sensor surface using dip coating. Cyclodextrins have a hydrophobic cavity, which favors the accommodation of an organic molecule of appropriate dimensions leading to a non-covalent inclusion complex. The temporal sensor response reveals a multi-exponential rise towards an equilibrium state, whose level is found to be linearly related to the exposed analyte concentration. Taking into account the spectr…