The compound undergoes a magnetic Co-Co sublattice ordering at similar to 150 K, and a second magnetic Dy-Dy sublattice ordering transition at 22 K. Magnetization and modified Arrott plots indicate that DyCo3B2 compound undergoes a second-order phase transition at
similar to 22 K. A large reversible magnetocaloric effect has been observed around Dy-Dy sublattice ordering temperature. The values of maximum magnetic entropy change (-Delta S-M(max)) reach 7.4 and 15.1 J kg(-1) K-1 for the field change of 2 and 7 T with no obvious hysteresis loss around 25 K; the corresponding values 5-Fluoracil mouse of maximum adiabatic temperature changes (Delta T-ad(max)) are evaluated to be 6.4 and 13.8 K, respectively. The large reversible Delta S-M(max) and Delta T-ad(ma), as well as considerable relative cooling power, make DyCo3B2 compound a suitable candidate for low temperature magnetic refrigeration. (C) 2011 American Institute of Physics. [doi: 10.1063/1.3572060]“
“Controlled thermoresponsive PET track-etched membranes were synthesized by grafting N-isopropylacrylamide (NIPAAm) onto the membrane www.selleckchem.com/products/ew-7197.html surface via atom transfer radical polymerization (ATRP). The initial measurements were made to determine the anchoring of ATRP initiator on PET membrane surface. Thereafter, polymerization was carried out to control the mass
of polymer by controlling reaction time grafted from the membrane surface and, ATR-FTIR, grafting degree measurements, water contact angle measurements, TGA, and SEM were used to characterize changes in the chemical functionality, surface and pore morphology of membranes as a result of modification. Water flux measurements were used to evaluate the thermoresponsive capacity of grafted membranes. The results show the grafted PET track-etched membranes exhibit rapid and reversible response of permeability to environmental
temperature, and its permeability could be controlled by controlling polymerization selleck inhibitor time using ATRP method. (C) 2011 Wiley Periodicals, Inc. J Appl Polym Sci 122: 2047-2053, 2011″
“Although the origins of the high effective permittivity observed in CaCu3Ti4O12 (CCTO) ceramics and single crystals at similar to 100-400 K have been resolved, the relaxorlike temperature- and frequency-dependence of permittivity obtained from fixed frequency capacitance measurements at higher temperatures reported in the literature remains unexplained, especially as CCTO adopts a centrosymmetric cubic crystal structure in the range of similar to 35-1273 K. Impedance spectroscopy studies reveal that this type of relaxorlike behavior is an artifact induced mainly by a nonohmic sample-electrode contact impedance. In addition, an instrument-related parasitic series inductance and resistance effect modifies the measured capacitance values as the sample resistance decreases with increasing temperature.