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This study presents an investigation on polyimides derived from a unfunctionalized symmetric cyclopentyl-containing alicyclic cardo-type dianhydride with ester linkage 1,1-bis(4-(3,4-dicarboxylbenzoyloxy)phenyl)cyclopentylene dianhydride (BDPCP) that was readily accessed starting from cyclopentanone through two steps in high yield. Two series of polyimides, Cardo-type series (CPI-x) and analogous aromatic series (ArPI-x) were prepared from condensation of BDPCP and aromatic 3,3′,4,4′-Oxydiphthalic dianhydride with four aromatic diamines, respectively. Comparative studies revealed that CPI polymers show more favorable properties including better solubility in organic solvents, higher transparency with lower cut-off wavelength (λ0) ranging in 395–375 nm than 425–405 nm, lower water absorption ranging in 0.66–1.14% and surface energy 23.71–32.77 mN/m than 1.01–1.28% and 29.52–41.99 mN/m of ArPI analogs. Meanwhile, CPI series exhibit considerable mechanical properties with tensile strengths ranging in 87.6–102.9 MPa, elongations at break 6.6–8.9%. Owing to the moderate strain in cyclopentyl ring, CPI series retain good thermal properties with the glass transition temperature (Tg) in the range of 217–271°C. Dynamic dielectric measurement revealed that Cardo-type dianhydride BDPCP endows CPI-4 film with lower dielectric constant (e′) 3.34 at 1 MHz and 25°C and dielectric loss (e′′) 0.0064 at 1 kHz and 25°C than 3.49 and 0.013 for ArPI-4 film. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42670.

Coordination bonds are effective for constructing functional self-healing materials due to their tunable bond strength and metal-ion-induced functionalities. In this work, we incorporate a cobalt(II) triazole complex into a polydimethylsiloxane (PDMS) matrix. The resulting polymers show solvatochromic behaviour as well as self-healing properties.

High Efficiency Video Coding (HEVC) is a new generation video coding standard by Joint Collaborative Team on Video Coding (JCTVC). The development of HEVC aims at the compression for ultra high definition videos. In HEVC, the encoder adopts a quad-tree based video coding structure, in which each incoming frame is split into a set of coding tree blocks (CTB) for compression. Each CTB can be recursively split into coding unit (CU), predict unit (PU) and transform unit (TU). This paper proposes an early termination algorithm of recursive partition based on the Sobel edge density of CTB in HEVC intra coding mode. The proposed method can reduce the depth of recursive partition for each CTB and thus save a lot of encoding time. Experimental results by HM10.1 show that the average time savings is about 14.2% and the resultant increase of encoded BD-Rate is only 0.02%. The proposed method can achieve significant time savings with negligible BD-Rate increase.