We synthesized two polyimides (PIs), poly(4,4′-(9,9-fluorenyl) diphenylene cyclobutanyltetracarboximide) and poly(4,4′-(9,9-fluorenyl) diphenylene pyromellitimide), and investigated in detail the surface morphology,...
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ISBN:
(纸本)1420061828
We synthesized two polyimides (PIs), poly(4,4′-(9,9-fluorenyl) diphenylene cyclobutanyltetracarboximide) and poly(4,4′-(9,9-fluorenyl) diphenylene pyromellitimide), and investigated in detail the surface morphology, molecular orientation, and nematic liquid crystal alignments of rubbed PI films. This study found that both the PIs are promising alignment layer materials for the fabrication of advanced LC display devices.
Shapes and structures of star-polystyrenes bearing 6 to 57-arms were in detail investigated in good and theta solvents by small-angle X-ray scattering with synchrotron radiation sources.
ISBN:
(纸本)1420063766
Shapes and structures of star-polystyrenes bearing 6 to 57-arms were in detail investigated in good and theta solvents by small-angle X-ray scattering with synchrotron radiation sources.
Solution small angle X-ray scattering (SAXS) is an effective technique for measuring structure and structural difference of protein under various environments, quantitatively. Structural characteristics of various con...
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ISBN:
(纸本)1420061828
Solution small angle X-ray scattering (SAXS) is an effective technique for measuring structure and structural difference of protein under various environments, quantitatively. Structural characteristics of various conformational states of porcine pepsin were studied in terms of size and shape under several pH conditions by solution SAXS. Under nearly physiologically enzymatic active conditions, the reconstructed models exhibit a more extended C-terminal domain, when compare to the crystal structure. The structural differences between solution and crystal structure of pepsin can be accounted for the inherent conformations of the flexible subdomain in the C-terminal domain in solution under carefully controlled specific pH conditions. Furthermore, this flexibility may provide a clue that lead to the solution of enzymatic inactivity of pepsin under mild acidic conditions. The structural evidences presented may have important implication in establishing relationship between the structure of porcine pepsin and its enzymatic function.
We chose two synthetic polymers (poly(vinylidene fluoride-co- hexafluoropropylene) and Nafion-117®) and studied their biocompatibility to several bacteria that are most notorious for opportunistic and iatrogeni...
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ISBN:
(纸本)1420061836
We chose two synthetic polymers (poly(vinylidene fluoride-co- hexafluoropropylene) and Nafion-117®) and studied their biocompatibility to several bacteria that are most notorious for opportunistic and iatrogenic infections.
In attempts to develop novel functional additives for thermoplastic and thermoset polymer coatings, various sizes of microcapsules containing a silicone fluid which could facilitate the release of the coating from a m...
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In attempts to develop novel functional additives for thermoplastic and thermoset polymer coatings, various sizes of microcapsules containing a silicone fluid which could facilitate the release of the coating from a metallic substrate were prepared by in-situ polymerization. Fill content, size of capsules, wall-thickness, and surface morphology were observed by TGA, TEM, SEM, EDX, optical and NMR microscopy. The capsules were dispersed in polymeric coatings and the release of their content through mechanical means was followed microscopically.
The controlled self-assembly of thiol stabilized gold nanocrystals in a mediating solvent and confined within mesoporous alumina was probed in situ with small angle x-ray scattering. The evolution of the self-assembly...
The controlled self-assembly of thiol stabilized gold nanocrystals in a mediating solvent and confined within mesoporous alumina was probed in situ with small angle x-ray scattering. The evolution of the self-assembly process was controlled reversibly via regulated changes in the amount of solvent condensed from an undersaturated vapor. Analysis indicated that the nanoparticles self-assembled into cylindrical monolayers within the porous template. Nanoparticle nearest-neighbor separation within the monolayer increased and the ordering decreased with the controlled addition of solvent. The process was reversible with the removal of solvent. Isotropic clusters of nanoparticles were also observed to form temporarily during desorption of the liquid solvent and disappeared upon complete removal of liquid. Measurements of the absorption and desorption of the solvent showed strong hysteresis upon thermal cycling. In addition, the capillary filling transition for the solvent in the nanoparticle-doped pores was shifted to larger chemical potential, relative to the liquid/vapor coexistence, by a factor of 4 as compared to the expected value for the same system without nanoparticles.
Nondestructive damage sensing and load transfer mechanisms of thermal treated carbon nanotube (CNT) and nanofiber (CNF)/epoxy composites were investigated using electromicromechanical technique. Carbon black (CB) was ...
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Nondestructive damage sensing and load transfer mechanisms of thermal treated carbon nanotube (CNT) and nanofiber (CNF)/epoxy composites were investigated using electro-micromechanical technique. Carbon black (CB) was...
Nondestructive damage sensing and load transfer mechanisms of thermal treated carbon nanotube (CNT) and nanofiber (CNF)/epoxy composites were investigated using electro-micromechanical technique. Carbon black (CB) was used only for the comparison. Electro-micromechanical techniques were applied to obtain the fiber damage and stress transferring effect of carbon nanocomposites with their contents. Thermal treatment and temperature affected on apparent modulus and electrical properties on nanocomposites due to enhanced inherent properties of each CNMs. Coefficient of variation (COV) of volumetric electrical resistance can be used to obtain the dispersion degree indirectly for various CNMs. Dispersion and surface modification are very important parameters to obtain improved mechanical and electrical properties of CNMs for multifunctional applications. Further optimized functionalization and dispersion conditions will be investigated for the following work continuously.
We proposed an approach to precisely control the density of tethered chains on solid substrates using PEO-b-PS and PLLA-b-PS. As the crystallization temperature Tx increased, the PEO or PLLA lamellar crystal thickness...
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We proposed an approach to precisely control the density of tethered chains on solid substrates using PEO-b-PS and PLLA-b-PS. As the crystallization temperature Tx increased, the PEO or PLLA lamellar crystal thickness dL increased as well as the reduced tethering density σ˜ of the PS chains. The onset of tethered PS chains overcrowding in solution occurs at σ˜*∼3.7–3.8 as evidenced by an abrupt change in the slope between (dL)−1 and Tx. This results from the extra surface free energy created by the tethered chain that starts to affect the growth barrier of the crystalline blocks.
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