Because carotenoids coexist at room temperature as a mixture of isomers, the 2PA spectra reported here are due to samples containing
a distribution of isomers, presenting distinct conjugation length and conformation. We show that these compounds present a defined structure on the 2PA spectra, that peaks at 650 nm with an absorption cross-section of approximately 5000 GM, for both compounds. In addition, Caspase inhibition we observed a 2PA band at 990 nm for beta-apo-8′-carotenal, which was attributed to a overlapping of I(I)B(u) +-like and 2(I)Ag(-)-like states, which are strongly one- and two-photon allowed, respectively. Spectroscopic parameters of the electronic transitions to singlet-excited states, which are directly related to photophysical properties of these compounds, were obtained by fitting the 2PA spectra using Silmitasertib Metabolism inhibitor the sum-over-states approach. The analysis and interpretations of the 2PA spectra of the investigated carotenoids were supported by theoretical predictions of one- and two-photon transitions carried out using the response functions formalism within the density functional theory framework, using the long-range corrected CAM-B3LYP functional. (C) 2011 American Institute of Physics. [doi:10.1063/1.3590157]“
“The results of the investigation of the mechanical properties of polyethylene (PE)
blends with
small (<3 wt %) additions of thermotropic liquid-crystalline polymers (LCPs) are reported. PE/LCP compositions with various LCP weight contents were obtained by thermoplastic mixing in a two-stage process. Short-term and long-term mechanical behavior of various PE/LCP compositions https://www.sellecn.cn/products/birinapant-tl32711.html were analyzed. Data on the influence of LCP addition on the tensile elastic modulus [or Young's modulus (E)], stress at yield (sigma(Y)), stress at break (sigma(B)), strain at yield, strain at break, and deformation at long-term (1000-h) tensile creep were obtained. The experimental results of the investigation show that even small additions of LCP allowed considerable increases in E, sigma(Y), sigma(B), and creep resistance of PE. To support the experimental data, we mathematically analyzed the elastic properties of the materials by taking into account the effect of self-reinforcement due to the formation of extended LCP inclusions. The results of the theoretical analysis testify that LCP inclusions in the continuous PE matrix were elongated 5-10 times because of their orientation during the manufacturing of the test specimens. Analytical descriptions of the creep of the PE/LCP blends are also presented. It is demonstrated that the creep behavior of the PE/LCP blends could be sufficiently well described by power law. (C) 2011 Wiley Periodicals, Inc.