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61.
Murat Cetinkaya Niranjan Malvadkar Melik C. Demirel 《Journal of Polymer Science.Polymer Physics》2008,46(6):640-648
This study describes the evolution and growth of structured polymers by oblique angle deposition of poly(p‐xylylene) (PPX) derivatives. The deposition of structured PPX polymers have been demonstrated recently, but the mechanism of growth has not been studied. Here, we provide experimental evidence for the growth of structured PPX polymers by an atomic force microscope, electron microscope, and a profilometer. Individual columns expand with respect to their heights according to a power‐law, d = chp, where d is the column diameter, c and p are constants, and h is the height of a column. Values of p for structured poly(chloro‐p‐xylylene), poly(trifloroacetly‐p‐xylylene‐co‐p‐xylylene), and poly(bromo‐p‐xylylene) films are estimated as 0.11 ± 0.01, 0.15 ± 0.01, and 0.18 ± 0.01, respectively. This result is different from the traditional oblique angle deposition processes of nonpolymeric materials where the surface diffusion is low. Further analysis with two‐dimensional power spectral density (PSD) method showed that the ordering of columns is quasi‐periodic. Additionally, the X‐ray and transmission electron microscope characterization of the columns revealed that the columns are semicrystalline. © 2008 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 46: 640–648, 2008 相似文献
62.
We study the arithmetic aspects of the finite group of extensions of abelian varieties defined over a number field. In particular, we establish relations with congruences between modular forms and special values of L-functions. 相似文献
63.
64.
In this paper a necessary and sufficient condition has been obtained for Σan∈n to be summable |N, q| whenever Σan is bounded (N, p, q). 相似文献
65.
Rajat Dutta Nilendu Panda Sukdeb Banerjee Manuela Weber Niranjan P. Sahu 《Tetrahedron letters》2004,45(51):9361-9364
A one-pot synthesis of substituted oxazino-2-quinolones is described. The cornerstone of this methodology involves PTC catalyzed addition of an ethylene dihalide to a quinol to generate the corresponding O-alkylated intermediate in situ followed by ring closing and subsequent formation of a carbonyl group in the oxazinoquinolone in a one-pot sequence. 相似文献
66.
Srebro M Govind N de Jong WA Autschbach J 《The journal of physical chemistry. A》2011,115(40):10930-10949
Time-dependent density functional theory (TDDFT) computations are performed for 42 organic molecules and three transition metal complexes, with experimental molar optical rotations ranging from 2 to 2 × 10(4) deg cm(2) dmol(-1). The performances of the global hybrid functionals B3LYP, PBE0, and BHLYP, and of the range-separated functionals CAM-B3LYP and LC-PBE0 (the latter being fully long-range corrected), are investigated. The performance of different basis sets is studied. When compared to liquid-phase experimental data, the range-separated functionals do, on average, not perform better than B3LYP and PBE0. Median relative deviations between calculations and experiment range from 25 to 29%. A basis set recently proposed for optical rotation calculations (LPol-ds) on average does not give improved results compared to aug-cc-pVDZ in TDDFT calculations with B3LYP. Individual cases are discussed in some detail, among them norbornenone for which the LC-PBE0 functional produced an optical rotation that is close to available data from coupled-cluster calculations, but significantly smaller in magnitude than the liquid-phase experimental value. Range-separated functionals and BHLYP perform well for helicenes and helicene derivatives. Metal complexes pose a challenge to first-principles calculations of optical rotation. 相似文献
67.
Synthesis of core-shell polystyrene nanoparticles by surfactant free emulsion polymerization using macro-RAFT agent 总被引:1,自引:0,他引:1
Novel approach for the synthesis of core-shell polystyrene nanoparticles by living hydrophilic polymer consisting of thiocarbonyl thio end group is reported. The surfactant free emulsion polymerization of styrene in the presence of macro-RAFT (reversible addition fragmentation chain transfer) agent is carried out to synthesize stable latex particles with smaller particle size. A macro-RAFT agent is prepared by homopolymerization of sodium styrene sulfonate (NaSS) in aqueous phase by using dithioester as chain transfer agent. This synthesized polystyrene sulfonate-sodium (PSS-Na) based macro-RAFT agent, which is essentially water soluble macromolecular chain transfer agent used for the surfactant-free batch emulsion polymerization of styrene. Transmission electron microscopy (TEM) study of the synthesized colloids shows the narrow particle size distribution with core-shell morphology. 相似文献
68.
Niranjan Yeole Dilip Hundiwale 《Colloids and surfaces. A, Physicochemical and engineering aspects》2011,392(1):329-334
Here we report, synthesis of different molecular weight poly (styrene sulfonate) based macro-RAFT agents and their use as shell material in surfactant-free emulsion polymerization of styrene. Concentration and molecular weight of hydrophilic macro-RAFT agent has an influence on colloidal stability, particle size distribution and self-assembly. Microscopic and zeta-potential studies of colloids reveal that, the macro-RAFT agents used with low molecular weight (Mn = 1200) are comparable more efficient than high molecular weight (Mn = 46,800 and 116,000) for imparting narrow particle size distribution with good colloidal stability. 相似文献
69.
Pundarikakshudu Kilambi Sharma Anilkumar S. Bhatt Chaitanya J. Kanaki Niranjan S. 《平面色谱法杂志一现代薄层色谱法》2014,27(5):362-366
JPC – Journal of Planar Chromatography – Modern TLC - The fruit of Piper longum Linn. (family: Piperaceae), known as pippali in India, is a reputed drug of Ayurveda (the Indian system... 相似文献
70.
Corrigendum: Spontaneously Self‐Assembled Naphthalimide Nanosheets: Aggregation‐Induced Emission and Unveiling a‐PET for Sensitive Detection of Organic Volatile Contaminants in Water 下载免费PDF全文
Niranjan Meher Prof. Parameswar Krishnan Iyer 《Angewandte Chemie (International ed. in English)》2018,57(34):10791-10791