SIZE DISTRIBUTIONS OF OCCUPATIONAL AIRBORNE ASBESTOS TEXTILE FIBRES AS DETERMINED BY TRANSMISSION ELECTRON MICROSCOPY

The nanocrystals Ce0.5Zr0.5O2 solid solutions with various morphologies and crystal structures have been synthesized via a modified sol-gel method assisted with a template. Aerosol OT and/or ionic liquids ([MMIM]Cl] and [BMIM]Cl]) was used as a template. The characterization results of the X-ray diffraction, transmission electron microscopy and N2 adsorption at 77 K indicate that the physical properties of the solid solutions were significantly affected by the templates used and the calcination temperatures. The Ce0.5Zr0.5O2 calcined at 773 K possessed bimodal mesopores, narrow pore size distributions, and tetragonal phase.

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Characteristics of fine pores in some halloysites

Clay Minerals ◽

10.1180/claymin.1995.030.2.01 ◽

1995 ◽

Vol 30 (2) ◽

pp. 89-98 ◽

Cited By ~ 71

Author(s):

G. J. Churchman ◽

T. J. Davy ◽

L. A. G. Aylmore ◽

R. J. Gilkes ◽

P. G. Self

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

New Zealand ◽

Nitrogen Adsorption ◽

Size Distributions ◽

Small Particles ◽

Transmission Electron ◽

Cylindrical Pores ◽

Large Particles ◽

Nm Range

AbstractIsotherms were obtained for nitrogen adsorption and desorption on seven halloysite-rich samples from New Zealand and Western Australia. Calculations from these isotherms indicate that halloysites with mainly small particles (<c. 0.08 μm in width) had abundant cylindrical pores with narrow size distributions in the 5-15 nm range. They also indicate that halloysites with mainly large particles (>c. 0.1 μm in width) had few if any pores in the mesopore range (2–50 nm). Transmission electron microscopy (TEM) shows that cylindrical pores originate from the central holes in tubular particles. The TEM also suggests that slit-shaped pores can originate from the shrinkage of blocks of layers upon dehydration of halloysite.

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Size-broadening anisotropy in whole powder pattern fitting. Application to zinc oxide and interpretation of the apparent crystallites in terms of physical models

Journal of Applied Crystallography ◽

10.1107/s0021889808012223 ◽

2008 ◽

Vol 41 (3) ◽

pp. 615-627 ◽

Cited By ~ 50

Author(s):

N. C. Popa ◽

D. Balzar

Keyword(s):

Electron Microscopy ◽

Transmission Electron Microscopy ◽

A Priori ◽

Physical Models ◽

Powder Pattern ◽

Size Distributions ◽

Complementary Information ◽

Transmission Electron ◽

Zno Powder

A new anisotropic size-broadening model based on a spherical-harmonics representation allowing determination of both volume- and area-averaged apparent crystallites and convenient for implementation into Rietveld programs is described. The model effectiveness is demonstrated on a ZnO powder pattern exhibiting strongly anisotropic size broadening and pronounced super-Lorentzian peak shapes. Moreover, it is shown how the apparent crystallites can be interpreted in terms of physical models by using ellipsoidal and cylindrical crystallites with lognormal size distributions. This interpretation is critically assessed and it is argued that both simplified physical models anda prioricomplementary information (obtained by transmission electron microscopy, for instance) are often needed to avoid unstable and non-unique solutions.

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