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991.
激光二极管相对于铯饱和吸收D2线的无调制扰动三次谐波锁频 总被引:5,自引:1,他引:4
将频率调制加在声光调制器上 ,用三次谐波探测法获得了铯原子D2 线的三阶微分饱和光谱。采用这种激光器无调制扰动方案结合三次谐波锁频技术 ,实现了 85 2nm的分布布拉格反射器半导体激光器相对于 6S1/2 F =4- 6P3 /2 F′ =5超精细跃线的频率锁定。由锁定后的频率误差信号估算 ,10s内激光频率起伏小于± 35 0kHz ,相对频率稳定度约 1× 10 -9。这种无调制扰动方案可以消除一般的饱和吸收稳频方法中由于直接对激光器进行频率调制而带来的额外频率噪声 ;三次谐波锁频技术的应用 ,还可有效地降低铯原子饱和吸收谱中剩余多普勒背景的影响 相似文献
992.
993.
A scheme is developed for analysing the interaction between a foundation and a nonlinear rock and soil medium, in which the
foundation is considered as a linear elastic body and a typical boundary integral equation method (BIEM) is employed. On the
basis of taking the nonlinear properties of the medium into account, a perturbation BIEM is developed. The fundamental equations
for the nonlinear coupling analysis are formulated, and typical problems are solved and discussed by the present method. 相似文献
994.
Sincethedevelopmentofmethodslformassproductionoffullerenes,therehasbeengTeatinterestinit-Manyresearchgroups'havepaidgreatattentiontothefiJllerene-dopedpolymersinceWang'discoveredinl992thatfullerene-dopedPVKhasanapparentlyincreasingphotoconductivity.WehavereportedthechendcalattachmentofCcocagestothecarbazolegroupsonpoly(epoxypropylcarbazole)(PEPC)chainsbyFriedel-Craftstypereaction'.Here,theopticalpropertiesoffullerenatedPEPCwereinvestigated,whichwillshowitsgoodphotoconductivepropeFtiesbe… 相似文献
995.
Chow HS Constable EC Housecroft CE Kulicke KJ Tao Y 《Dalton transactions (Cambridge, England : 2003)》2005,(2):236-237
Electron exchange between [Co(terpy)2]3+ and [Co(terpy)2]2+ can be monitored by 1H NMR exchange spectroscopy and allows the cobalt(II) spectra to be fully assigned. 相似文献
996.
Gao W Yang T Wang Y Li G Liao F Lin J 《The journal of physical chemistry. B》2005,109(48):22775-22779
A series of Cr-incorporated PKU-1 molecular sieves (Cr-PKU-1) were synthesized by using boric acid as a flux, and the physicochemical properties were characterized by XRD, ICP, SEM, XPS, UV-vis, and NH3-TPD methods. The morphology of Cr-PKU-1 is a needlelike hexagonal prism with uniform size of about 2 microm in diameter and 20-50 microm in length. XRD and UV-vis provide direct evidence that Cr ions have been successfully incorporated into the framework of PKU-1. NH3-TPD shows a dramatic increase of acidic sites in the Cr-PKU-1 in comparison with PKU-1, indicating that the Cr incorporation can significantly modify the acidity of the compound. In addition, the incorporated Cr ions may act as redox centers, thus catalytic performance of Cr-PKU-1 molecular sieve was investigated by the selective oxidation of styrene under mild reaction conditions. 相似文献
997.
Min Zhang Lu Bai Tao Yuan Lewei Li Zhensen Wu 《International Journal of Infrared and Millimeter Waves》2005,26(2):315-327
An effective technique to characterize multilayered millimeter wave structure with vertical via-holes connected is presented. The advantage of this method is the closed-form Greens functions in spatial domain for general electric and magnetic sources in multilayered medium are obtained easily in terms of the two-level discrete complex image method (DCIM) with the high-order Sommerfeld identities, which only four elements of Greens functions in spectral domain are needed. In addition, the curl operators in mixed potential integral equations (MPIE) are avoided effectively from the Greens functions in this paper. A low temperature co-fired ceramic (LTCC) aperture coupled antenna with vertical via-holes connected is analyzed to prove the accuracy and efficiency of this technique on three-dimensional (3-D) multilayered structure with vertical components. 相似文献
998.
Dialkylamino acetonitrile derivatives were utilized as alternative to cyanohydrin synthons for preparation of the corresponding heteroaryl dialkyl amides via a strategy of sequential base-mediated coupling and oxidation. The most advantageous oxidant, NiO(2)-H(2)O, can readily oxidize 2-substituted aminoacetonitriles to the corresponding amides under both basic and neutral conditions by forming cyanohydrins in situ. 相似文献
999.
McArthur EA Ye T Cross JP Petoud S Borguet E 《Journal of the American Chemical Society》2004,126(8):2260-2261
Detection and quantification of submonolayer coverage surface species is not trivial. We have developed a novel method sensitive to surface-bound chemical functional groups as low as 10(11) molecules/cm(2) by specific covalent attachment of fluorescent chromophores. This enables the intermediates of the UV photochemistry of alkylsiloxane self-assembled monolayers to be identified. 相似文献
1000.
Lina Geng Tao Bo Huwei Liu Na Li Feng Liu Kean Li Junling Gu Ruonong Fu 《Chromatographia》2004,59(1-2):65-70
A new capillary coating of alternate -zirconium phosphate lysozyme fabricated for open-tubular electrochromatography enantioseparation. The chiral compounds D, L-tryptophan tested were enantiomerically resolved. The influences brought by experimental parameters, such as organic modifier, temperature, applied voltage and pH of running buffer on the performance of the column, were investigated. 相似文献