The synthesis, X-ray crystal structures, and photochemical behavior of a series of methyl- and ethylene-bridge-substituted trans-4-(N-(4-cyanophenyl)amino)stilbenes (3-8) are reported and compared to those of the parent compound 1CN. Aminostilbene 1CN displays dual fluorescence in polar solvents due to planar and twisted intramolecular charge-transfer (PICT and TICT) states. Alkyl substitution on the stilbene group of 1CN significantly perturbs its photochemistry, including fluorescence, trans --> cis photoisomerization, and TICT state formation. The alkyl substituent effect can be dissected into electronic and steric influences, and both are position dependent, which is vinyl alpha-carbon > vinyl beta-carbon > phenyl o-carbon. The main outcome of the alkyl substituent effect is to lower the barrier for the singlet-state photoisomerization. As a result, the quantum yield for photoisomerization is increased, and that for fluorescence is reduced. The corresponding quantum yield for TICT state formation in polar solvents is reduced only when significant ground-state twisting (a steric influence) is present. The alkyl substitution exerts little or no effect on the rate of intersystem crossing.

Abstract-In this paper, we address the challenges of content transfer in opportunistic networks, and propose techniques to better facilitate data dissemination based on the characteristics of the content. To investigate this problem from its origins, we propose three message scheduling algorithms: Sequential Forwarding (SF), Full Interleaving (FI), and Block-based Interleaving (BI). Each algorithm is embedded in a specially tailored data dissemination technique to evaluate the benefits of applying it to different types of content and data dissemination methods. Three types of content (file, video and web) are considered and evaluated, and the dissemination methods considered are Layered Multiple Description Coding (LMDC) based and file-based. Using simulations as well as both synthetic and realistic network scenarios, we evaluate the proposed schemes in terms of latency and user perceived quality, and demonstrate how the schemes can achieve much better latency performance for file transfers. Furthermore, we show that using LMDC-based techniques leads to higher user perceived quality, since the end user is allowed to "preview" video file or web content, even before the data has been completely transferred. The effectiveness and robustness of our message scheduling algorithms and their corresponding content dissemination techniques make them ideal solutions that can go a long way toward effective data dissemination in opportunistic networks.

One-dimensional nanostructures of BaO-xTiO 2 binary oxides with a high oxygen deficiency and a good dielectric performance are of great interest but seldom studied. In the present study, single-crystalline BaTi 4 O 9 (stoichiometric BaO-4TiO 2 ) nanowires were synthesized using a simple, one-step molten-salt method by co-heating the powder mixtures of NaCl, TiO 2 and BaCl 2 nanoparticles at 750 uC. A series of spontaneous processes in the molten NaCl/BaCl 2 salt mixture with the dispersed TiO 2 nanoparticles, including ion diffusion, chemical reaction, particle agglomeration and ion exchange, yielded the BaTi 4 O 9 nanowires. Photoelectron spectroscopic and dielectric analyses indicated that a high fraction of oxygen deficiency for 10.4% provided the as-synthesized BaTi 4 O 9 nanowires with a high capacitance density of 13 F/m 2 . Thermal annealing lowered the oxygen deficiency to 6.6% and the capacitance density to 9 F/m 2 .The increase in wire length increased the oxygen deficiency and dielectric constant of the nanowires.

This study proposes using an inductively coupled plasma etching process to fabricate notched long-period fiber grating (NLPFG) for sensor applications. The effects of the designed parameters (i.e., different fiber cladding thicknesses, grating periods, and etching depths) are studied to explore the characterization of NLPFG. The characterization as indicated by tests of the NLPF showed that the wavelength of NLPFG produced a redshift with decreases in cladding thickness. The drift rate of the wavelength following changes in thickness was -2.801  nm/μm. In addition, a redshift also was exhibited in the increased period, with a wavelength drift rate corresponding to the size of the period of 1.466  nm/μm. Moreover, the results showed that the transmission loss in the spectra increased with etching depth. The variation rate of transmission loss based on etching depth was -0.458  dB/μm.