The low-temperature variation of the elastic constants of lithium hydride and lithium deuteride

AbstractHigher order elastic constants have been calculated in hexagonally structured superionic conductor Li3N at room temperature using the interaction potential model. The temperature variation of the ultrasonic velocities was evaluated along different angles with z axis (unique axis) of the crystal, using the second order elastic constants. The ultrasonic velocity decreased with the temperature along a particular orientation of the unique axis. Temperature variation of the thermal relaxation time and Debye average velocities was also calculated along the same orientation. The temperature dependency of ultrasonic properties was discussed in correlation with elastic, thermal and electrical properties. It has been found that the thermal conductivity is the main contributor to the behavior of ultrasonic attenuation as a function of temperature and the cause responsible for attenuation is phonon-phonon interaction. The mechanical properties of Li3N at low temperature are better than at high temperature because at low temperature it has low ultrasonic attenuation. Superionic conductor lithium nitride has many industrial applications, such as those used in portable electronic devices.

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On the theory of the temperature variation of the elastic constants of solid solutions of alkali halides

Soviet Physics Journal ◽

10.1007/bf00895712 ◽

1973 ◽

Vol 16 (6) ◽

pp. 866-868

Author(s):

A. A. Botaki ◽

O. V. Danilin ◽

A. V. Sharko

Keyword(s):

Temperature Variation ◽

Solid Solutions ◽

Elastic Constants ◽

Alkali Halides

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Infestation of froghopper nymphs changes the amounts of total phenolics in sugarcane

Scientia Agricola ◽

10.1590/s0103-90162005000600005 ◽

2005 ◽

Vol 62 (6) ◽

pp. 543-546 ◽

Cited By ~ 6

Author(s):

Rafael José Navas da Silva ◽

Eduardo Rossini Guimarães ◽

José Francisco Garcia ◽

Paulo Sérgio Machado Botelho ◽

Maria Inês Tiraboschi Ferro ◽

...

Keyword(s):

Phenolic Compounds ◽

Low Temperature ◽

Temperature Variation ◽

Total Phenolics ◽

The Other ◽

Plant Phenolics ◽

High Moisture ◽

Randomized Design ◽

Leaf Tissues ◽

Completely Randomized Design

The increased rate of sugarcane harvest without previous burn has provided a very favorable environment to the froghopper Mahanarva fimbriolata (Stal, 1854), with high moisture and low temperature variation. Few works have studied the response of sugarcane to this pest, so little is known about resistant cultivars. Plant phenolics are widely studied compounds because of their known antiherbivore effect. This research aims to determine if the attack of M. fimbriolata nymphs stimulates the accumulation of total phenolics in sugarcane. The experiment was carried out in greenhouse and arranged in completely randomized design, in a 3 X 2 X 4 factorial with three replications. Second instar nymphs of M. fimbriolata were infested at the following rates: control, 2-4 and 4-8 nymphs per pot (first-second infestations, respectively). Pots were covered with nylon net and monitored daily to isolate the effect of leaf sucking adults. Leaf and root samples were collected and kept frozen in liquid nitrogen until analyses. Infested plants showed higher levels of phenolics in both root and leaf tissues. In roots, the cultivar SP80-1816 accumulated more phenolic compounds in response to the infestation of M. fimbriolata. On the other hand, higher levels were found in leaves and roots of control plants of SP86-42, which might be an indication of a non-preference mechanism. The increase of total phenolics in sugarcane infested with root-sucking froghopper nymphs does not seem to be useful to detect the resistance to this pest.

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Defects and Ion Transport Properties of Yttrium Doped Zirconia

MRS Proceedings ◽

10.1557/proc-453-549 ◽

1996 ◽

Vol 453 ◽

Author(s):

P. J. Chaba ◽

P. E. Ngoepe

Keyword(s):

Molecular Dynamics ◽

Oxygen Vacancy ◽

Ion Transport ◽

Transport Properties ◽

Temperature Variation ◽

Yttrium Oxide ◽

Elastic Constants ◽

Oxygen Transport ◽

Solid Oxide ◽

Set Up

AbstractA comparison of calculated and experimental temperature variation of elastic constants were used to predict types of oxygen—vacancy dopant clusters in yttria stabilised cubic zirconia, which serves as an electrolyte in solid oxide fuelcells. Such clusters were incorporated in supercells set up for molecular dynamics studies, where oxygen transport properties were investigated at concentrations of 9.4 and 24 mol % of yttrium oxide and up to 1600K.

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