ReTiO 3+␦/2 ͑Re= La and Nd͒ thin films have been deposited on ͑100͒LaAlO 3 substrates using the pulsed laser deposition technique. The oxygen content in the formula can be tuned to some extent by carefully adjusting the oxygen pressure during film deposition. When grown at higher oxygen pressures, the films tend to be in their fully oxidized insulating form Re 2 Ti 2 O 7 ͑␦ =1,Ti 4+ ͒ with a twinned monoclinic structure of ͓012͔ m orientations. When grown in a background vacuum around 5 ϫ 10 −4 Pa, the films are lightly hole doped ͑␦ ϳ 0, ϳ Ti 3+ ͒ and retain the near-cubic perovskite structure with the ͓001͔ c axis perpendicular to the film surface, though high-density defects may exist. These two phases coexist in the films grown at intermediate oxygen pressures. For the vacuum-grown near-cubic films, the antiferromagnetic ordering dies in the lanthanum titanate due to oxygen doping but still survives in the neodymium titanate owing to the higher electron correlation strength in the latter. The transport behavior in the ϳTi 3+ Mott insulating films can be described well by the small-polaron hopping or variable range hopping model. In the hole-doped metallic films, a temperature-dependent carrier density and Hall mobility were observed, especially at low temperatures. The temperature dependence of the resistance can be almost perfectly fitted by a small-polaron coherent conduction model ͓R s ͑T͒ = R s ͑0͒ + C ␣ / sinh 2 ͑T / T͔͒.
Three-dimensional velocity distributions in the entry region of a rectangular slit contraction were investigated using a dual-beam laser Doppler velocimeter. The flow of a silicone oil (a Newtonian fluid) and a solution of silicone rubber in the same silicone oil (a viscoelastic fluid) was studied at low Reynolds numbers (Re < 0.5). In contrast to the usual velocity distribution of a Newtonian fluid, the viscoelastic fluid showed the following characteristic features: (1) a pronounced axial velocity overshoot immediately after the slit entrance and a maximum before the slit exit; (2) appearance of an axial flow deceleration region just before the sharp acceleration near the slit entrance. Even rnore remarkably, a saddle form of velocity profile was found in the entrance region. This flow pattern is completely different from that found for Newtonian fluids and has not yet been explained using existing rheological analysis.
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