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991.
992.
High aspect-ratio, single crystal BaWO4 nanowires with diameters as small as 3.5 nm and lengths up to more than 50 microns were synthesized in catanionic reverse micelles formed by an equimolar mixture of two surfactants: undecylic acid and decylamine. 相似文献
993.
In this paper, we describe a practical, useful electrophilic aromatic nitration process in fluorous phase by using perfluorodecalin (C10F18, cis- and trans-mixture) as a fluorous solvent and perfluorinated rare earth metal salt [Yb(OSO2C8F17)3] as a catalyst for the electrophilic aromatic nitration. 相似文献
994.
High chemical yields and good enantiomeric excesses are obtained by using soluble polymer-supported tartrate ester in the epoxidation of trans-hex-2-en-1-ol using Ti(OPri)4/tert-butyl hydroperoxide. 相似文献
995.
996.
Let G be a finite group and
e(G) the set of element orders of G. Denote by h(
e(G)) the number of isomorphism classes of finite groups H satisfying
e(H) =
e(G). We prove that if G has at least three prime graph components, then h(
e
(G)){1, }. 相似文献
997.
High-efficiency coupling structure for a single-line-defect photonic-crystal waveguide 总被引:1,自引:0,他引:1
Prather DW Murakowski J Shi S Venkataraman S Sharkawy A Chen C Pustai D 《Optics letters》2002,27(18):1601-1603
We present the design and fabrication of a planar structure for coupling light from a multimode feed waveguide into a single-line-defect photonic-crystal waveguide. Finite-difference time-domain calculations predict a coupling efficiency of greater than 90%, and preliminary experimental results indicate successful coupling through a single-line-defect photonic-crystal waveguide. Device design, fabrication, and characterization are presented. 相似文献
998.
Highly ordered Prussian blue nanowires with diameter of about 50 nm and length up to 4 m have been fabricated by an electrodepositing technology with two-step anodizing anodic aluminum oxide films. The Mössbauer spectra taken between 15 and 300 K indicate that the hyperfine parameters decrease as the temperature increases. The temperature dependence of the quadrupole splitting, the isomer shift and the spectra area are discussed. A decrease of Debye temperature for Prussian blue nanowires was found with respect to that of Prussian blue bulk. 相似文献
999.
Gd,-.Na.CuO#, an interesting compound with complex magnetic behavior, has beensynthesized by a PbO-based flux method (l) and a solid state reaction (2) at temperaturesabout 1000"C. Its X-ray diffraction pattern has been indexed with tetragonal latticeparameters (l,3). Here we report a low temperature synthetic route in which the newmonoclinic form of Gd,-.Na.CuO# is obtained directly by precipitation from a moltenKOH/NaOH/KNO, solution. The SEM, EDX, XRD, XPS and magnetic characte… 相似文献
1000.
A simple method for quantitative analysis of aesculin and aesculetin in Cortex fraxini was developed using capillary zone electrophoresis (CZE). Berberin was employed as an internal standard, The running buffer was 6 mM Na(2)B(4)O(7) and 10 mM NaH(2)PO(4) (pH 6.70). The linear calibration range was 32-256 mug ml(-1) (r=0.9996) for aesculin and 23-230 mug ml(-1) (r=0.9993) for aesculetin. The contents of aeculin and aesculetin in C. fraxini were easily determined within 12 min the pKa values of aesculin and asculetin determined by CZE were 6.56 and 5.62, respectively. A simple method for estimation of the temperature inside the capillary during running was also proposed. 相似文献