Simple thermal treatment approach for the synthesis of α-Zn2SiO4 nanoparticles

Selected area electron diffraction (SAD) has been used successfully to determine crystal structures, identify traces of minerals in rocks, and characterize the phases formed during thermal treatment of micron-sized particles. There is an increased interest in the method because it has the potential capability of identifying micron-sized pollutants in air and water samples. This paper is a short review of the theory behind SAD and a discussion of the sample preparation employed for the analysis of multiple component environmental samples.

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Development of Crystallinity in Turbostratic Boron Nitride Derived from Polymeric Precursors

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100089081 ◽

1991 ◽

Vol 49 ◽

pp. 954-955

Author(s):

X. Qiu ◽

A. K. Datye ◽

T. T. Borek ◽

R. T. Paine

Keyword(s):

Thermal Treatment ◽

Boron Nitride ◽

Diffraction Pattern ◽

Polymeric Precursors ◽

Polymer Precursors ◽

Diffuse Ring

Boron nitride derived from polymer precursors is of great interest for applications such as fibers, coatings and novel forms such as aerogels. The BN is prepared by the polymerization of functionalized borazine and thermal treatment in nitrogen at 1200°C. The BN powders obtained by this route are invariably trubostratic wherein the sheets of hexagonal BN are randomly oriented to yield the so-called turbostratic modification. Fib 1a and 1b show images of BN powder with the corresponding diffraction pattern in fig. 1c. The (0002) reflection from BN is seen as a diffuse ring with occational spots that come from crystals of BN such as those shown in fig. 1b. The (0002) lattice fringes of BN seen in these powders are the most characteristic indication of the crystallinity of the BN.

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Productivity of Emerging Word Combinations in Toddlers With Specific Expressive Language Impairment

American Journal of Speech-Language Pathology ◽

10.1044/1058-0360.0604.34 ◽

1997 ◽

Vol 6 (4) ◽

pp. 34-47 ◽

Cited By ~ 6

Author(s):

Steven H. Long ◽

Lesley B. Olswang ◽

Julianne Brian ◽

Philip S. Dale

Keyword(s):

Data Collection ◽

Young Children ◽

Language Impairment ◽

Treatment Approach ◽

Expressive Language ◽

Semantic Consistency ◽

Session Analysis

This study investigated whether young children with specific expressive language impairment (SELI) learn to combine words according to general positional rules or specific, grammatic relation rules. The language of 20 children with SELI (4 females, 16 males, mean age of 33 months, mean MLU of 1.34) was sampled weekly for 9 weeks. Sixteen of these children also received treatment for two-word combinations (agent+action or possessor+possession). Two different metrics were used to determine the productivity of combinatorial utterances. One metric assessed productivity based on positional consistency alone; another assessed productivity based on positional and semantic consistency. Data were analyzed session-by-session as well as cumulatively. The results suggest that these children learned to combine words according to grammatic relation rules. Results of the session-by-session analysis were less informative than those of the cumulative analysis. For children with SELI ready to make the transition to multiword utterances, these findings support a cumulative method of data collection and a treatment approach that targets specific grammatic relation rules rather than general word combinations.

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