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Z. Malek V. Balek D. Garfinkel-Shweky S. Yariv 《Journal of Thermal Analysis and Calorimetry》1997,48(1):83-92
The dehydration and dehydroxylation of the smectites, beidellite and montmorillonite (dioctahedral) and saponite and laponite (trioctahedral), were investigated by ETA, DTA, TG and X-ray diffractions. There are differences between the behaviors of di- and trioctahedral clays which are due to the differences in the ability of the exchangeable cations to migrate into hexagonal holes of the SiO4 network and due to the fact that the dehydroxylation and recrystallization of dehydroxylated trioctahedral smectites occur simultaneously, whereas there is a temperature gap of about 300°C between the dehydroxylation and the recrystallization of dioctahedral smectites.Dedicated to Dr. Robert Mackenzie on the occasion of his 75th birthdayThe authors wish to thank Laporte Industries, Inc. UK for the laponite sample.This research was supported under Project No. C12-219, Grant No. HRN5544 G002069, U.S.-IsraelCooperative Development Research Program, Office of the Science Advisor, U.S. Agency for International Development. 相似文献
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Hirobumi Takahashi Takehiro Fukami Hisaki Kojima Takeru Yamakawa Hiroyuki Takahashi Toshihiro Sakamoto Teruyuki Nishimura Masayuki Nakamura Takashi Yosizumi Kenji Niiyama Norikazu Ohtake Takashi Hayama 《Tetrahedron》2005,61(14):3473-3481
A robust synthetic method for 2-alkylamino-6-carboxy-5,7-diarylcyclopenteno[1,2-b]pyridines via acylamination at the alpha position of the functionalized pyridine system has been developed. The key step in this method was achieved by treatment of the corresponding pyridine N-oxides with 2.5 equiv of imidoyl chlorides in the presence of triethylamine, thus producing the desired 2-acylaminopyridines in good yields (74-96%). 相似文献
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V. Balek T. Mitsuhashi J. Šubrt P. Bezdička J. Fusek 《Journal of Thermal Analysis and Calorimetry》2000,60(2):691-698
Emanation Thermal Analysis (ETA) was used to characterize microstructure changes of hydrous ruthenia and hydrous ruthenia-titania
as precursors for preparation of RuO2 and (RuO2)0.9-(TiO2)0.l by heating in the temperature range of 20–600°C in argon. A good agreement was found between ETA, TG and DTA results, X-ray
diffraction patterns and surface area measurements of intermediate products of the thermal treatment.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
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《Analytical letters》2012,45(5):1341-1354
Abstract Twelve procedures of sample pretreatment for manganese determination in blood serum were tested in comparable instrumental conditions. the best results were obtained by dilution of serum with diluted nitric acid, which leads to formation of an internal matrix modifier composed of calcium and phosphoric acid. Other procedures may also give satisfactory results, but then as standards aqueous albumin solutions should be used. 相似文献
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Extended topochemical atom (ETA) indices developed by our group have been extensively applied in our previous reports for toxicity and ecotoxicity modelling in the field of quantitative structure–activity relationships (QSARs). In the present study these indices have been further explored by defining additional novel parameters to model n-octanol–water partition coefficient (two data sets; n?=?168 and 139), water solubility (n?=?193), molar refractivity (n?=?166), and aromatic substituent constants π, MR, σ m, and σ p (n?=?99). All the models developed in the present study have undergone rigorous internal and external validation tests and the models have high statistical significance and prediction potential. In terms of Q 2 and r 2 values the models developed for the datasets of whole molecules are better than those previously reported, with topochemically arrived unique (TAU) indices on the same datasets of chemicals. An attempt has also been made to develop models using non-ETA topological and information indices. Interestingly, ETA and non-ETA models have been found to have similar predictive capacity. 相似文献
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Emanation
thermal analysis (ETA) was used to characterize microstructure changes during
heating of Mg–Al–CO3 layered double hydroxide
(LDH) in the temperature range of 293–1473 K. It was confirmed by ETA
that the formation of an intermediate phase with grafted CO32–
anions in the hydroxide layers took place in the temperature range of 508–523
K and the formation of Mg–Al mixed oxide (MO) occurred in the range
623–773 K. The small peak of the emanation rate at 603 K indicated the
degradation of the layered structure and the broad peak in the range of 1073–1273
K characterized the onset of the separation of the decomposition products
of MO into MgO and Mg2Al4O7.
The ETA results revealed that dehydration of the product with grafted CO32–
anions occurred at lower temperatures than that of the initial Mg–Al–CO3
LDH. 相似文献
10.
Balek V. Šubrt J. Rouquerol J. Llewellyn P. Zeleňák V. Bountsewa I. M. Beckman I. N. Györyová K. 《Journal of Thermal Analysis and Calorimetry》2003,71(3):773-782
Emanation thermal analysis (ETA) was used for thermal characterization of microstructure changes taking place during heating
of synthetic gibbsite sample in argon in the range of 25–1200°C. Microstructure development and the increase of the surface
area under in-situ conditions of the sample heating were characterized. The increase of the radon release rate from 130–330°C
monitored the increase of the surface area due to the dehydration of Al(OH)3. During heating of the sample in the range 450–1080°C the ETA results characterized the annealing of surface and near surface
structure irregularities of intermediate products of gibbsite heat treatment. The mathematical model for the evaluation of
the ETA experimental results was proposed. From the comparison of the experimental ETA results with the model curves it followed
that the model is suitable for the quantitative characterization of microstructure changes taking place on heating of gibbsite
sample.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献