Electrical properties of lead telluride single crystals doped with Gd
Temperature dependences of electric conductivity, free carrier concentration and mobility in single-crystalline PbTe: Gd samples with a varied impurity content are investigated. The features of electron transport in PbTe: Gd may be caused by a variable gadolinium valence. The striking result from the Seebeck coefficient measurements is that the thermoelectric power factor increases dramatically. Measurements of the magnetic susceptibility at low temperatures permit us to suggest that Gd ions exist in different charge states.
Models for low-dimensional thermoelectricity
Enhanced thermoelectric performance, expressed in terms of the thermoelectric figure of merit (ZT), has been predicted theoretically for low-dimensional electronic systems under appropriate experimental conditions. Enhanced ZT has been observed experimentally within 2D quantum wells of PbTe, and good agreement between theory and experiment has been obtained. The advantages of low-dimensional systems for thermoelectric applications are described, and prospects for further enhancement of ZT are discussed.
Why Biblical Texts Cannot Be Dated Linguistically
Zechariah 1-8 is an important text from the point of view of the history of the Hebrew language. Everyone can agree that it is post-exilic, and yet there are only a few traces of Late Biblical Hebrew in these chapters. In this regard it equals many Early Biblical Hebrew texts. The article examines the language of Zechariah 1-8 and compares it to Early Biblical Hebrew. It finds that Zechariah 1-8 exhibits a number of traits characteristic of Early Biblical Hebrew and rare in Late Biblical Hebrew. Holding this fact together with the absence of any significant Late Biblical Hebrew features, the article concludes that the text is an Early Biblical Hebrew text. If correct, this means that knowledge of Early Biblical Hebrew did not end with the Exile and raises the question of how long this knowledge lasted.