Results 181 to 190 of about 9,594 (205)

Silica xerogels as pharmaceutical drug carriers

Expert Opinion on Drug Delivery, 2009
This review focuses on silica xerogels obtained by the sol-gel method and their application as drug delivery systems. SiO(2) xerogels are potential biomaterials to be used as matrix materials for the extended and controlled release of different kinds of biologically active agents administered by various routes.
David, Quintanar-Guerrero, Adriana, Ganem-Quintanar, María Guadalupe, Nava-Arzaluz, Elizabeth, Piñón-Segundo   +3 more
openaire   +2 more sources

Carbon Xerogels for Effluent Treatment

Journal of Chemical & Engineering Data, 2020
The adsorption process of carbonized xerogels in the form of porous microspheres or monoliths was found to be reversible.
Athulya Pillai, Balasubramanian Kandasubramanian   +1 more
openaire   +1 more source

Similarity of cellulose xerogels of japanese pears in ultrastructure to chitin xerogels chemically prepared

International Journal of Biochemistry, 1978
Abstract 1. 1. Ultrastructure of cellulose (cell wall) xerogels of Japanese pears was compared with that of chitin xerogels chemically prepared, and molecular assemblies of chitin chains to gels was examined by scanning electron microscopy (SEM). 2. 2.
S, Hirano, R, Yamaguchi, N, Matsuda, H, Takeuchi   +3 more
openaire   +2 more sources

Low-Energy Vibration Excess in Silica Xerogels

Physical Review Letters, 1997
Specific heat (1.5-25 K) and Raman scattering (below 100cm −1 in silica xerogels permit one to assess the frequency dependence of the coupling coefficient C(ω)and the low-energy density of states g(ω) Different network connectivity does not change the shape of the quasielastic scattering, but alters the spectral shape of C(ω)The results permit one to ...
FONTANA A, ROSSI F, CARINI, Giuseppe, D'ANGELO, Giovanna, TRIPODO, Gaspare, BARTOLOTTA A.   +5 more
openaire   +4 more sources

CdS semiconductor doped silica xerogels

Materials Science and Engineering: A, 1993
Abstract CdS doped amorphous silica was prepared by the sol-gel method. The CdS concentration in weight varied from 5% to 20%. The samples were characterized by four different and complementary techniques: X-ray diffraction (XRD), high resolution transmission electron microscopy (HRTEM), low frequency inelastic Raman scattering (LOFIRS) and small ...
A. Othmani, C. Bovier, J.C. Plenet, J. Dumas, B. Champagnon, C. Mai   +5 more
openaire   +1 more source

Elastic Properties of Silica Xerogels

Journal of the American Ceramic Society, 1990
To calculate elastic constants, longitudinal and tranverse acoustic wave velocities were measured for silica xerogels as a function of relative humidity (rh). The silica xerogels studied are microporous with open porosity of 53 vol%. The longitudinal wave velocity exhibits a minimum at about 35% rh.
Lisa C. Klein, Bennet Abramoff
openaire   +2 more sources

Tunable dye-doped xerogel lasers

Conference on Lasers and Electro-Optics Europe, 1994
The easiest route to produce tunable optical pulses is to use a broadband fluorescent gain medium. For this purpose organic dye molecules are very suitable and have been widely used in solution during the past 30 years. Today, new crystals such as titanium sapphire, and nonlinear techniques such as optical parametric oscillation, may provide solid ...
M. Canva, P. Georges, A. Dubois, A. Brun, F. Chaput, J.-P. Boilot   +5 more
openaire   +1 more source

Structural characterization of silica xerogels

Journal of Non-Crystalline Solids, 1995
The structure of silica xerogels prepared following a fully inorganic route was investigated by means of the concurrent use of gas-adsorption, solid-state nuclear magnetic resonance and neutron diffraction techniques. Such an approach enables consistent estimates for the particle and pore sizes to be derived which show the existence of microporous ...
M.J. Muñoz-Aguado, M. Gregorkiewitz, F.J. Bermejo   +2 more
openaire   +1 more source

Thermal stability of xerogel films

Thin Solid Films, 2001
In this work, we have investigated the thermal stability of the organic component of porous SiO2 (xerogel) films using a combination of ion beam techniques and thermal desorption spectroscopy (TDS). Ion beam techniques reveal a large concentration of carbon and hydrogen atoms in this film.
A. Kumar, H. Bakhru, J.B. Fortin, G.-R. Yang, T.-M. Lu, C. Jin, W.W. Lee   +6 more
openaire   +1 more source

Mechanical Properties of Silica Xerogels

Journal of the American Ceramic Society, 1991
Strengths have been measured for silica xerogels using four‐point bending. The silica xerogels studied are microporous with open porosity of 53 vol%. Strengths were measured on fresh samples, samples which had been outgassed at 250°C, samples which were exposed to ambient conditions for 2 d, and samples stored in ethanol.
Bennett Abramoff, Lisa C. Klein
openaire   +1 more source