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111.
Peichun Li Amar Zerroukhi Jianding Chen Yvan Chalamet Thomas Jeanmaire Zhean Xia 《Journal of polymer science. Part A, Polymer chemistry》2008,46(23):7773-7784
Ti[O(CH2)4OCH?CH2]4, used for the ring‐opening polymerization (ROP) of ε‐caprolactone, was synthesized through the ester‐exchange reaction of titanium n‐propoxide and 1,4‐butanediol vinyl ether, and its chemical structure was confirmed by nuclear magnetic resonance (1H NMR) and thermogravimetric analysis (TGA). The mechanism and kinetics of Ti[O(CH2)4OCH?CH2]4‐initiated bulk polymerization of ε‐caprolactone were investigated. The results demonstrate that Ti[O (CH2)4OCH?CH2]4‐initiated polymerization of ε‐caprolactone proceeds through the coordination‐insertion mechanism, and all the four alkoxide arms in Ti[O (CH2)4OCH?CH2]4 share a similar activity in initiating ROP of ε‐caprolactone. The polymerization process can be well predicted by the obtained kinetic parameters, and the activation energy is 106 KJ/mol. Then, the rheological method was employed to investigate the feasibility of producing the crosslinked poly(ε‐caprolactone)‐poly (n‐butyl acrylate) network by using Ti[O(CH2)4OCH?CH2]4 as the ROP initiator. The tensile test demonstrates that the in situ generated crosslinked PCL‐PBA network in PMMA matrix provides the possibility of ameliorating the tensile properties of PMMA. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 7773–7784, 2008 相似文献
112.
Vladimir Chechersky Nikolai S. Kopelev Beom-hoan O Michael I. Larkin Jian-Liang Peng John T. Markert Richard L. Greene Amar Nath 《Hyperfine Interactions》1994,93(1):1721-1726
Mössbauer effect studies suggest the presence of extraneous oxygen in the whole family of title compounds. At certain concentrations of Ce, oxygen is rather tenaciously bound. Such oxygen causes superparamagnetism in the magnetically ordered material, and also brings about the formation of spin clusters in the metallic material. 相似文献
113.
The main result of this paper establishes that the irregularity strength of any tree with no vertices of degree two is its number of pendant vertices. 相似文献
114.
Amar Maheshwari 《Pramana》1986,27(3):383-391
The complete expression of the five-dimensional Einstein-Hilbert action as an expansion in fields in the Appelquist-Chodos
parametrization of the Kaluza-Klein metric has been given in this paper. It is explicitly shown that a unitary gauge can be
fixed in which in each of the charge sectors the vector and the scalar fields are absorbed as Goldstone modes leaving behind
the Pauli-Fierz Lagrangian for massive charged spin-2 field. 相似文献
115.
Two-dimensional flows with suction or mass loss are investigated within Darcy’s or Stokes’ framework. Examples include a Hele-Shaw
cell with a lifted plate or extraction of lipids from a lipid bilayer. An initially circular patch ret-racts due to the suction
and might undergo an instability whereby it becomes undulating. The selection of the wavelength of undulations is investigated
with the help of an extremum principle, the minimization of the generalized dissipation, from which derive the flow equations. 相似文献
116.
J. W. Hewage F. G. Amar M.-F. de Feraudy G. Torchet 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2003,24(1-3):249-252
Using realistic pair potentials, we investigate the
structures of mixed clusters of argon and nitrogen in order to
interpret the experimental electron diffraction patterns
reported by the Torchet group. Simulations of small clusters
indicate that argon tends to segregate at the center of the
clusters. For larger clusters, in the range of 50 to 200
molecules, MC methods have been used to simulate structures that
are likely to be generated in the molecular beam. By comparing
predicted electron diffraction patterns with those recorded in
the experiments, our models allow us to estimate the average
size and composition of the mixed clusters for a given set of
experimental conditions (nozzle stagnation pressure and Ar
partial pressure). 相似文献
117.
Iron(III)-doped titania nanoparticles were prepared by modified sol-gel method using titanium (IV) butoxide and inorganic precursor iron(III) nitrate nonahydrate. Spectroscopic measurements show the onset of the band-gap transition to be red-shifted (~λ = 475 nm) to the visible region with increasing iron(III) ion content. Characterizations were preformed by X-ray diffractometry, electron microscopy, energy dispersive X-ray spectroscopy and X-ray photoelectron spectroscopy. Photocatalysis experiments were performed with dye pollutant sulforhodamine-B in aqueous environment. Direct photocatalytic effect was observed in the dye degradation experiments when irradiated with visible light into the band gap of the iron(III)-doped titania. 相似文献
118.
Amar Nath Nigam 《Zeitschrift für Physik A Hadrons and Nuclei》1957,147(3):264-270
Possible correlations of the energy levels arising due to colour centers in a potassium halide crystal with the X-ray absorptions fine structure of potassium ion are discussed. Influence of the inner ionisation on the activation energy of the ions and on the potential surrounding them has been estimated using approximate equations. 相似文献
119.
Effect of absorber thickness on the X-ray K absorption edge of nickel has been recorded photographically. The extended structures show a variation in their relative intensities. In agreement with the earlier observations of Parratt and Sawada the structures in the immediate neighbourhood of the edge show a decrease in their absorption intensities and the fluctuations following them up to 140 eV. remain unaltered. In addition, it is found that the structures lying beyond 150 eV. from the edge become more pronounced on the increase of absorber thickness. 相似文献
120.
P. Ramesh Kumar M. Venkateswarlu Manjusri Misra Amar K. Mohanty N. Satyanarayana 《Ionics》2013,19(3):461-469
Lithium manganese phosphate (LiMnPO4) nanorods were synthesized using the modified polyol method. Polyvinylpyrrolidone was used as a stabilizer to control the shape and size of LiMnPO4 nanorods. Resin coating process was used to coat the carbon over the LiMnPO4 nanorods. X-ray diffraction and Fourier transform infrared spectroscopy results showed the formation of LiMnPO4 crystalline phase. The TEM image shows a uniform coating of the nano size (2.3 nm) carbon over the surface of LiMnPO4 nanorods and the EDS spectrum of the carbon-coated LiMnPO4 nanorods confirming the presence of carbon element along with the other Mn, P, and O elements. Impedance measurements were made on pure and carbon-coated LiMnPO4 nanorods, and their conductivities were evaluated by analyzing the measured impedance data using the WinFIT software. More than two orders of magnitude of conductivity enhancement was observed in the carbon-coated LiMnPO4 nanorods compared to pure ones, and the conductivity enhancement may be attributed to the presence of carbon over LiMnPO4 nanorods. Temperature dependence of conductivity and ac conductivity were calculated using impedance data of pure and carbon-coated LiMnPO4 nanorods. CR2032 type lithium ion coin cells were fabricated using pure and carbon-coated LiMnPO4 nanorods and characterized by measuring charge–discharge cycles between 2.9 and 4.5 V at room temperature. More than 25 % of improved capacity was achieved in the carbon-coated LiMnPO4 nanorods when compared to pure ones synthesized using modified polyol and resin coating processes. 相似文献