Sexting Research Articles

Positron lifetimes in liquid SeTe alloys

Measurements of positron lifetime in Se xTe 1−x alloys with x = 0, 0.2, 0.4 and 0.6 have been carried out in the solid and liquid states. The temperature dependence of lifetime is closely related to the change in the density. The lifetime reflects the structural modification and the associated change in the electronic structure with temperature. The dependence of lifetime on temperature and concentration is qualitatively explained provided the two kinds of trapping sites are taken into account in the liquid SeTe alloy.

Transport at the mobility edge in liquid semiconductors

Thermoelectric transport at the mobility edge is interpreted in terms of a variable conductivity at the mobility edge σ c, assuming that R in Mott's formula σ c = 610/R is the distance between negatively charged centers. This leads to information about the concentration c − of negative charges as well as the distance ε Fl of the Fermi energy from the mobility edge. Applying this model to new Se xTe 1−x data, we find that c − has an activation energy ∼ 0.25 eV when x>0.4, and increases more rapidly with T at x = 0.40. There is a change in dε Fl / dT at ε Fl ⋟ 0.08 eV . probably caused by holes becoming the dominant positively charged species.

Change of bonding system in liquid Se xTe 1−1 alloys as shown by density measurements

Density measurements have been performed on melts in the binary chalcogenide system Se x Te 1− x up to a temperature of 950°C. Anomalous behaviour of the density was observed. At higher temperatures the density increased on raising the temperature up to a maximum whose position shifts to lower temperatures with increasing concentration of tellurium. This anomalous density behaviour clearly shows an increase of the average coordination number of atoms in the melt. This increase of CN is caused by a change of the bonding system because of the tendency of Te to form pσ bondings. It was assumed that there exist two distinct structures in thermodynamical equilibrium at each temperature according to a law of mass action, for which cooperation effects have to be taken in account. At low temperatures Te atoms easily accept a loosely packed structure I with the aid of selenium. At high temperatures even Se atoms develop a more densely packed structure II with the aid of Te.

Solid immiscibility and liquid structure in the Ga 2(Se xTe 1− x) 3 alloy system

Differential thermal analysis and X-ray diffraction studies of the system Ga 2(Se x Te 1− x ) 3 are reported and correlated with measurements of the electrical conductivity in the liquid state. The experiments reveal that Ga 2Te 3 and Ga 2Se 3 do not form a continuous series of pseudo-binary solid solutions but exhibit solid state immiscibility in the range 0.50 ≲ x ≲ 0.90. The composition dependence of the conductivity of the liquid alloys exhibits structure in the range of the solid state phase separation. Such “memory” in the liquid of a solid phase separation has not been reported previously and suggests the importance of concentration fluctuations in determining the electronic properties of the liquid alloys.

Solid immiscibility and liquid structure in the Ga 2(Se xTe 1−x) 3 alloy system

Solid immiscibility and liquid structure in the Ga 2(Se xTe 1−x) 3 alloy system

Mechanoreceptors on the antenna of the tobacco hornworm moth (Manduca sexte)

Des etudes structurales fonctionelles suggerent une function mechanoreceptive pour le S. trichoidea sur l'antenne de la phaleneManduca sexta. Les soies de ses antennes sont innervees par un seul neurone bipolaire, dans lequel la dentrite est couronnee par une cellule scolopale. Les pointes positives dont l'amptitude varient ont ete enregistrees sur le nerf antennal avec deplacement transversal des soies antennales.