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131.
In this paper, we determine the isomorphism classes of contact simple Lie algebras constructed from locally-finite commuting derivations, introduced earlier by the second author. These algebras are in general not finitely graded.Supported by NSF grant 10171064 of China and two grants ``Excellent Young Teacher Program' and ``Trans-Century Training Programme Foundation for the Talents' from Ministry of Education of China
Mathematical Subject Classification (2000):Primary 17B65; Secondary 58F05 相似文献
132.
He Wen Huan Jiang Xiaoping Zheng Hanyi Zhang Yili Guo 《Photonics Technology Letters, IEEE》2007,19(18):1377-1379
In this letter, we propose two methods to enhance the performance of multichannel wavelength conversion of return-to-zero differential phase-shift-keying signal in a semiconductor optical amplifier (SOA) based on four-wave-mixing effect. The first one is optimizing the relative time delay of the multichannel signal to reduce the crosstalk-induced penalty in SOA. The second one is using the synchronous clock pumping to raise the power of converted signal. The experiment on wavelength conversion of two channels at 10-Gb/s signal showed the power penalty was improved more than 1 dB in the first method and about 1.5 dB in the second method. 相似文献
133.
Xiaoping Lai 《Multidimensional Systems and Signal Processing》2007,18(4):341-349
This paper presents an online procedure that produces the smallest feasible size of two-dimensional FIR filters with prescribed
magnitude error constraint. The procedure uses the mean square normalized error of constrained and unconstrained least-square
filters to produce the initial and the subsequent sizes that converge to the smallest feasible one in a few iterations, where
the constrained least-square filters are defined as the least-square filters satisfying the magnitude error constraint. The
procedure finally returns a smallest size filter that satisfies the magnitude error constraint and has least total squared
magnitude error. Design examples of diamond-shaped, rectangular, and elliptic filters are provided, and comparisons with an
exhaustive search are given. 相似文献
134.
135.
136.
Xiaoping Chen Neil Ayres 《Journal of polymer science. Part A, Polymer chemistry》2011,49(14):3030-3037
The synthesis of a molecular brush was accomplished by combining step‐growth polymerization and reversible addition fragmentation chain transfer (RAFT) polymerization in a “grafting from” methodology. A symmetrical N‐alkyl urea peptoid sixmer containing alkyne functional groups was prepared using a divergent strategy, and the structure of the product was confirmed using NMR spectroscopy and mass spectrometry. A step‐growth process was used to prepare a linear poly(N‐alkyl urea peptoid) by reacting the diamine‐functionalized N‐alkyl urea peptoid sixmer with a diisocyanate. RAFT chain transfer agents were coupled to the poly(N‐alkyl urea peptoid) backbone through a copper‐catalyzed azide/alkyne cycloaddition reaction. The afforded macro‐RAFT agent was used to sequentially polymerize styrene and tert‐butyl acrylate block copolymer arms from the poly(N‐alkyl urea peptoid) backbone. The tert‐butyl groups were removed using dilute trifluoroacetic acid affording hydrophilic polyacrylic acid segments. The molecular brushes were observed to generate micelles in aqueous solution. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
137.
Hua Zhu Xiaoping Xu Wei Cui Yuanqing Zhang Huaping Mo Yu‐Mei Shen 《Journal of polymer science. Part A, Polymer chemistry》2011,49(8):1745-1752
This article describes the synthesis and characterization of hydroxyl tailored, molecularly defined biodegradable cooligomers capable of chelating rhenium for potential radiopharmaceuticals. New insights were gained during the synthesis of lactide based on dimethylaminopyridine‐catalyzed transesterification. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011 相似文献
138.
In this paper, we construct infinite-band filterbanks for perfect reconstruction (PR) using Hermite polynomials and Hermite functions. The analysis filters are linear combinations of derivative operators based on these polynomials-the so-called chromatic derivative filters. Together with the synthesis filterbanks, they give PR for a large class of signals that may have infinite bandwidth. Several other related filterbanks are discussed as well. The error in reconstruction for finite-channel chromatic derivative filterbanks is calculated. Examples are given to demonstrate the use of these chromatic filterbanks. 相似文献
139.
Spline wavelet transform is used to resolve overlapping voltammetric peaks. A suitable resolving factor is chosen to multiply the filters of spline wavelet and make it a peak resoluter. Simulated overlapping voltammetric peaks are processed by the peak resoluter and satisfactory results are obtained. Base-line separation can be achieved, the relative errors of peak position are less than 3.0%, and the relative errors of peak area are less than 5.0%. The effect of different resolving factors and spline wavelet basis are discussed. To test the procedure, two systems, cadmium (Ⅱ)-indium (Ⅲ) and lead (Ⅱ)-thallium (Ⅰ), are used. 相似文献
140.
The microlens has been widely applied to improve the sensitivity and to decrease the spatial crosstalk of image sensors. In order to further decrease the pixel size while improve the image quality, the zero gap microlens has been proposed to make high performance image sensors. In this paper, both the traditional microlens and zero gap microlens are fabricated using TOWER and TOPPAN processes. And their performances are compared and evaluated. The results show that the least sensitivity of the zero gap microlens has been significantly improved by more than 45.8% compared to that of the traditional microlens. The use of the zero gap microlens results in an obvious decrease of the crosstalk among blue, green and red lights. For example, the crosstalk of blue light in red light under the green irradiation has been decreases about 1.33%, and the crosstalk of red light in blue light under the blue irradiation has showed about 2.429 times decrease. Overall, the output colour image of the zero gap microlens is brighter and clearer than that of the traditional microlens. Image quality has been significantly improved due to the use of the zero gap microlens. 相似文献