Spectral Properties of Rhodamine 3B Adsorbed on the Surface of Montmorillonites with Variable Layer Charge

Langmuir ◽  
2007 ◽  
Vol 23 (4) ◽  
pp. 1851-1859 ◽  
Author(s):  
Juraj Bujdák ◽  
Virginia Martínez Martínez ◽  
Fernando López Arbeloa ◽  
Nobuo Iyi
Keyword(s):  
Spectral Properties ◽  
Layer Charge ◽  
Variable Layer

Porosity of Synthetic Saponites with Variable Layer Charge Pillared by Al13 Polycations

Langmuir ◽  
1995 ◽  
Vol 11 (8) ◽  
pp. 2849-2852 ◽  
Author(s):  
L. Bergaoui ◽  
J. F. Lambert ◽  
M. A. Vicente-Rodriguez ◽  
L. J. Michot ◽  
F. Villieras
Keyword(s):  
Layer Charge ◽  
Variable Layer

Preparation and infrared spectroscopic characterization of reduced-charge montmorillonite with various Li contents

Clay Minerals ◽  
1996 ◽  
Vol 31 (2) ◽  
pp. 233-241 ◽  
Author(s):  
J. Madejová ◽  
J. Bujdák ◽  
W. P. Gates ◽  
P. Komadel
Keyword(s):  
Infrared Spectroscopy ◽  
Spectroscopic Characterization ◽  
Layer Charge ◽  
Preparation Temperature ◽  
Oh Groups ◽  
Tetrahedral Sheet ◽  
Increasing Temperature ◽  
Octahedral Cations ◽  
Variable Layer

AbstractA series of reduced-charge montmorillonites (RCMs) was prepared from Li-montmorillonite from Jelšový Potok (Slovakia) by heating at various temperatures (105–210°C for 24 h. The amount of fixed Li, 0.09–0.67 per O20(OH)4, increased with increasing temperature, confirming preparation of a set of samples of variable layer charge from the same parent Li-montmorillonite by varying only the preparation temperature. Infrared spectroscopy revealed that Li was trapped in the hexagonal cavities of the tetrahedral sheet at all temperatures. Partial deprotonation of the samples, reflected in the decrease of the intensities of the OH-bending bands, was observed after treatments above 120°C. Analysis of the OH-stretching region showed Li in the previously vacant octahedra in the samples heated above 150°C. Weak inflections near 660 and 720 cm−1 confirmed development of local trioctahedral character of octahedral cations coordinated with OH groups in the sample heated at 210°C. Gradual decrease of the layer charge due to Li fixation led to a shift of the Si-O stretching band to higher frequencies and to the appearance of new, pyrophyllite-like bands at 1120 and 419 cm−1.

Pillaring of Layered Double Hydroxides Possessing Variable Layer Charge with Vanadium Polyoxoanions

1994 ◽  
Vol 371 ◽  
Author(s):  
F. Kooli ◽  
V. Rives ◽  
M.A. Ulibarri ◽  
W. Jones
Keyword(s):  
Surface Area ◽  
Layered Double Hydroxides ◽  
Layer Charge ◽  
Second Phase ◽  
Textural Characteristics ◽  
Al Content ◽  
Complete Exchange ◽  
Double Hydroxides ◽  
Charge Balancing ◽  
Variable Layer

AbstractA range of layered double hydroxides (LDHs) with Ni/Al and Mg/Al as the M(II)/M(III) cations and containing carbonate as the charge balancing anion have been synthesised. A variation in the M(II)/M(III) ratio between 2 and 6 has been attempted with the influence of the M(II)/M(III) ratio upon the subsequent exchange of carbonate by [V10O28]6- (at pH 4.5) examined. Complete exchange is obtained for all ratios, although the crystallinity of the products varies. For M(II)/M(III) ratios > 4, the product crystallinity is poor. In addition, a second phase is detected for all ratios. In the case of Ni/Al, the amount of vanadium incorporated is found to depend upon the Al content whereas for Mg/Al the amount incorporated is constant. Overall, the replacement of carbonate by decavanadate does not appear to have any significant effect on the textural characteristics (e.g. surface area or porosity) of the pillared products.

Model of multicomponent narrow-band periodical non-stationary random signal

2020 ◽  
Vol 2020 (48) ◽  
pp. 17-24
Author(s):  
I.M. Javorskyj ◽  
◽  
R.M. Yuzefovych ◽  
P.R. Kurapov ◽  
◽  
...  
Keyword(s):  
Time Series ◽  
Real Time ◽  
Hilbert Transform ◽  
Spectral Properties ◽  
Narrow Band ◽  
Analytic Signal ◽  
Random Signal ◽  
Hilbert Transformation ◽  
The Hilbert Transform

The correlation and spectral properties of a multicomponent narrowband periodical non-stationary random signal (PNRS) and its Hilbert transformation are considered. It is shown that multicomponent narrowband PNRS differ from the monocomponent signal. This difference is caused by correlation of the quadratures for the different carrier harmonics. Such features of the analytic signal must be taken into account when we use the Hilbert transform for the analysis of real time series.

Structure and Spectral Properties of New Composites Based on Metal Alkanoates with Gold Nanoparticles

2015 ◽  
Vol 60 (04) ◽  
pp. 356-361 ◽  
Author(s):  
A. Tolochko ◽  
◽  
P. Teselko ◽  
A. Lyashchova ◽  
D. Fedorenko ◽  
...  
Keyword(s):  
Gold Nanoparticles ◽  
Spectral Properties
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