Spherulitic samples, which contained monoclinic lamellae, were prepared by slow cooling of the quiescent melt at rates lower than 10 K/s and by isothermal melt crystallization at temperatures between 373 and 413 K. Nonspherulitic specimens, which contained nonlamellar mesomorphic domains, in contrast, were obtained by rapid cooling of the melt with rates faster than 100 K/s. The crystallinity and the size of crystals were furthermore fine-tuned by subsequent annealing at elevated temperatures. Analysis of such films of different structure by ultraviolet visible spectroscopy revealed that the light transmission was independent of (1) the fraction, (2) the internal structure,

and (3) the size of the crystals. In contrast, the light transmission increased

with decreasing size of spherulites and finally exceeded 90% in films of 100 mu m thickness when spherulites Ferroptosis inhibitor were completely absent. The crystallinity and the structure and size of the crystals of the films of isotactic polypropylene could be adjusted within wide limits without affecting the light transmission. (C) 2010 Wiley Periodicals, Inc. J Appl Polym Sci 117: 1013-1020, 2010″
“Zinc oxide (ZnO) is semiconductor with a wide band gap of 3.4 eV. It continues to gain more attention not only for MEK162 solubility dmso its versatile use in industry but also its potential for further application in electronics, optics, spintronics, and transparent circuits. Many of these applications require p-type ZnO. Nitrogen substituting for oxygen is a possible acceptor for such applications. In this paper, we

report a study of nitrogen-hydrogen (N-H) complexes grown into single-crystal ZnO, using seeded chemical vapor transport in an ammonia ambient. An infrared (IR) absorption peak arising from N-H complexes was observed at 3150.6 cm(-1) at liquid-helium temperatures. The assignment of this peak was confirmed by nitrogen and hydrogen isotope substitution. LDN-193189 price Polarized IR spectroscopy shows that the N-H dipole is oriented at an angle similar to 114 degrees to the c axis, in agreement with previous first-principles calculations. To probe the stability of the N-H complexes, samples were annealed in air, oxygen, and argon. Samples annealed in oxygen at 725 degrees C showed a significant increase in resistivity, due to outdiffusion of hydrogen and compensation by nitrogen acceptors. (C) 2010 American Institute of Physics. [doi: 10.1063/1.3443457]“
“Aspects of network formation and the physical properties of stoichiometric amine-cured epoxy resins are investigated. The state of network formation is systematically controlled by using isothermal cure conditions and a linear temperature ramp condition. Affine deformation in compression at a constant true strain rate is used to measure the true stress-strain response from small strains to large strains.