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911.
In this paper, we prove that two rational maps with the Cantor Julia sets are quasicon- formally conjugate if they are topologically conjugate.  相似文献   
912.
本文首次报导了生长温度为550℃,以三甲基镓(TMGa)和三甲基铟(TMIn)为Ⅲ族源,用低压金属有机物气相沉积(LFMOCVD〕技术,高质量1.62um和1.3umInGaAsP及In0.57Ga0.43As0.98P0.04/In0.73Ga0.27As0.6P0.4量子阶结构的生长,并给出了1.55umGaAsP/InP分别限制应变量子阱结构激光器的生长条件,激光器于室温下脉冲激射,其阈值电流密度为2.4kA/cm2。  相似文献   
913.
从河南产的辛夷中首次发现了一种新的黄酮醇甙,用多种核磁共振方法并结合其它结构信息,研究和确定其化学结构为4',5,7-三羟基黄酮醇-β-7-O-(6"-对-香豆酰基)-D-葡萄糖甙,命名为望春花黄酮醇甙Ⅰ(Biondnoid A).  相似文献   
914.

There are large to superlarge magnesite and talc deposits occurring in Mg-rich carbonate formations distributed in the early Proterozoic Dashiqiao Formation in eastern Liaoning Province, China. The discovery of the sedimentary gypsum, isotopic geochemistry of δ18Osmow, δ13CPDB, δ34SVCDT and Sr/Ba ratio of carbonate, talc, quartz and gypsums with field investigation and sample analysis in laboratory demonstrate that the formation of magnesite and talc deposits is closely related to marine evaporates, which then underwent reworking of regional metamorphism and hydrothermal metasomatism. Metasomatic fluids originating from the paleoseawater played a controlling role in the formation of talc deposits.

  相似文献   
915.
胡椒碱的极谱分析研究   总被引:4,自引:0,他引:4  
孟召辉  汪振辉 《分析化学》1994,22(12):1263-1266
在pH2.2的Britton-Robinson缓冲溶液中,胡椒碱在-1.10V(us.SCE)左右产生一灵敏的极谱波,导数峰电流与胡椒碱浓度在0.05-8μg/ml范围内呈良好的线性关系。本法操作简便,快速,灵敏,选择性较好。用于天然胡椒果实中胡椒碱的测定,得到了满意结果。本文对极谱波性质及电极反应机理进行了研究。  相似文献   
916.
Analysis of the causes of formation of negative loss factors   总被引:2,自引:0,他引:2  
I-IatroductionStatisticalEnergyAnalysis(SEA)isakindofeffective,simpleanddirectapproachforan-alyzingvibrationandsound,andithasbeenfoundwidelyapplicationsinanalysisofmechanicalnoiseandvibrationcolltrolsince198osl1-4].However,forgeneralindustrialmachineswhichalwayconsistofcomPlexandheaVystructures,thedeterminationmethodsofSEAparametersintheclassicalSEAtheoryareinapplicable[5]because:(1)SEAparametersofthesekindsofstructuresaredifficulttoobtainfromthetheory(2)theconditionofconservativeandweak…  相似文献   
917.
918.
双面金属包覆介质波导的直接耦合方法   总被引:4,自引:1,他引:3  
根据双面金属包覆介质波导的特殊性质,提出了一种新的波导耦合方法,这种技术在不用棱镜、光栅和其它元件的情况下,可使光能从金属表面直接耦合进波导。实验结果与理论预言符合得很好。  相似文献   
919.
We adopt the group velocity approach to the issue of tunneling time in two configurations of magnetic barrier structures, which are arranged with identical or unidentical building blocks. The effects of an external electric field are also taken into account. The tunneling time in magnetic barrier structures is found to be strongly dependent on the magnetic configuration, the applied bias, the incident energy as well as the longitudinal wave vector. The results indicate that for electrons with equal energy but different incident angles, the tunneling processes are significantly separated in time within the same magnetic barrier structure. In the configuration arranged with unidentical building blocks, there exists obvious asymmetry of tunneling time in two opposite tunneling directions. Such a discrepancy of the tunneling time varies distinctly with the longitudinal wave vector and the applied bias. Received 4 March 2002 / Received in final form 22 May 2002 Published online 17 September 2002  相似文献   
920.
Laser flash photolysis with excitation at 248 nm was used to study photochemically derived changes of carboxymethylcellulose (CMC) in aqueous solutions. Transient absorption spectra of solutions after photolysis revealed a broad band with a maximum of approximately 720 nm, which could be ascribed to the signal of the hydrated electron. The interaction of the hydrated electron with CMC was slow (<107 dm3 mol?1 s?1), but the OH radical, formed by the decomposition of H2O2, reacted with CMC at a high rate constant (9.5–11.0 × 108 dm3 mol?1 s?1). The rate constant of the reactions of CMC with hydroxyl radicals depended on the conformation of the macromolecules, which was determined by the pH of the solution. Transient absorption was recorded at a wavelength shorter than 370 nm for CMC solutions photolyzed in the presence of H2O2. As a result of OH attack, long‐lived radicals were formed on CMC. The recombination of macroradicals led to the formation of crosslinking bonds between side‐chain groups, and as a result of it an insoluble gel arose in low‐pH solutions. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 505–518, 2005  相似文献   
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