The resistivity (T) and magnetoresistance ͑MR͒ (⌬/) of an entangled single-wall carbon-nanotube network are investigated. The temperature dependence of the resistivity shows a negative d/dT from T ϭ4.3-300 K with no resistivity minimum, which is fitted well to the two-dimensional variable-range-hopping ͑VRH͒ "(T)ϭ 0 exp͓(T 0 /T) 1/3 ͔… formula with T 0 ϭ259.2 K. The MR shows a negative H 2 behavior at low magnetic field. At Tр3.8 K and high magnetic field, the negative MR becomes positive. The positive MR tends to be saturated for HϾ10 T. The negative MR with a positive upturn can be decomposed into a positive contribution from the two-dimensional spin-dependent VRH and a negative contribution from the twodimensional weak localization, with some contribution of the Ni impurities in the sample found with the transmission electron microscope and by energy dispersive spectrometer analysis. ͓S0163-1829͑98͒07848-5͔

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Thermoelectric power (TEP) of high-T C superconductors has been investigated in a wide range of temperature (T C < T < 700 K) for La 2−x Sr x CuO 4 . TEP of La 2−x Sr x CuO 4 shows different temperature dependences in three temperature regions. In the low-temperature region, a positive broad TEP peak is observed near T p , which shifts to lower temperature upon doping. As temperature increases, TEP decreases linearly at intermediate temperature.In the high-temperature region, TEP deviates from the linear temperature dependence at a certain temperature, T h showing a saturation behavior. As the doping concentration increases, the characteristic temperatures, T C , T p , and T h , show systematic changes. In comparison with pseudogap temperature estimated from other experiments, the large pseudogap behavior in TEP at high temperature has been discussed and distinguished from the small pseudogap observed at lower temperature. A possibility of bound pairs formation in the normal state opening the pseudogap at high temperature is discussed briefly. The coexistence of bound pairs and the normal independent carriers for T C < T < T h could be the origin of the intrinsic inhomogeneity.

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