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Allowable irreducible representations of the point groups with five-fold rotations – that represent the symmetry of the quasicrystals in two and three dimensions – are derived by employing the little group technique in conjunction with the solvability property. The point groups D $_{5h} ({\overline {10} {\text{{\emph m}}}2})$ and ${\text{{\emph I}}}_h (\frac{2}{\text{{\emph m}}}\overline 3 \,\overline 5)$ are taken to illustrate the method. 相似文献
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Let Z r,R be the class of all continuous functions f on the annulus Ann(r, R) in the real hyperbolic space \(\mathbb B^n\) with spherical means M s f(x)?=?0, whenever s?>?0 and \(x\in\mathbb B^n\) are such that the sphere S s (x)???Ann(r, R) and \(B_r(o)\subseteq B_s(x).\) In this article, we give a characterization for functions in Z r,R . In the case R?=?∞, this result gives a new proof of Helgason’s support theorem for spherical means in the real hyperbolic spaces. 相似文献
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Allowable irreducible representations of the point groups with five-fold rotations – that represent the symmetry of the quasicrystals in two and three dimensions – are derived by employing the little group technique in conjunction with the solvability property. The point groups D $_{5h} ({\overline {10}}{m}2)$ and ${I}_h \left(\frac{2}{m}\overline {3} \,\overline {5}\right)$ are taken to illustrate the method. 相似文献
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基于中空纤维液相微萃取技术,建立了绿豆芽中吲哚类植物生长素的荧光检测方法。通过L9(34)正交实验,对中空纤维液相微萃取条件进行优化,得到的优化条件为:样品溶液的p H值调为4.0,萃取溶剂为正辛醇,接受相为p H 12.0的Na OH,搅拌速度为1 000 r/min,萃取时间为60 min。在最优萃取条件下,吲哚类植物生长素的富集倍数可达92倍。供体相中吲哚类植物生长素的质量浓度在1.71~50.0 mg/L范围内呈良好的线性关系,相关系数为0.997 9,检出限(S/N=3)为0.57 mg/L,样品的加标回收率为88.6%~100.7%,相对标准偏差(RSD)不大于4.8%。该方法操作简单,环境友好,可用于绿豆芽中吲哚类植物生长素含量的准确快速测定。 相似文献
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S ANANTHAKUMAR J JAYABALAN ASHA SINGH SALAHUDDIN KHAN SUBHASH PRAJAPATI S MOORTHY BABU RAMA CHARI 《Pramana》2014,82(2):353-358
In this article, we report size-dependent measurement of the shift in peak of upconversion photoluminescence spectra compared to that of normal photoluminescence using a 800 nm femtosecond laser and its second harmonic. It has been shown that the upconversion photoluminescence is always red-shifted compared to that of normal PL in all the samples. By measuring the power-dependent upconversion photoluminescence (UCPL), it has been shown that the origin of UCPL from MPA-capped CdTe nanoparticles is mainly of two-photon absorption 相似文献
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In this article, we report a method to achieve a precisely tunable highly stable probe beam generation for performing pump–probe experiment around a given wavelength by tilting a sum frequency generation (SFG) crystal angle. The width of the generated third-harmonic beam is of the order of 2 nm throughout the tunable range. This method of probe beam generation has its application in isolating contributions from closely separated excitation states. 相似文献
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SALAHUDDIN KHAN J JAYABALAN ASHA SINGH RAMA CHARI SUPARNA PAL S PORWAL T K SHARMA S M OAK 《Pramana》2014,82(2):359-364
We show that in a GaAs0.86P0.14/Al0.7Ga0.3As near-surface quantum well, there is coherent oscillation of holes observed in time-resolved reflectivity signal when the top barrier of the quantum well is sufficiently thin. The quantum well states interact with the surface states under the influence of the surface electric field. The time period of the observed oscillation is 120±10 fs. 相似文献
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The average static third-order polarizabilities (γ) have been computed for the bowls and cages having the same number of carbon atoms. The bowls have higher (γ) than their corresponding cages. The dependence of (γ) on the average pyrimidalized angle (Θp) and maximal length L can be deduced. Near cages, having one open window (C72 isomers), are capped with C6 to generate five isolated pentagon rule (IPR) isomers of C78 fullerenes following a circumscribing algorithm. The (γ) values for the C78's and C72′s are correlated with (Θp) and L. The change in (γ) from C72′s to C78′s are correlated with a local parameter like the capped angle (α). 相似文献
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AHMAD H. Badaruddin ARFAN Muhamma RAMA N. Hasan MALANA M. Aslam MAHBOOB Shahid 《中国化学》2007,25(1):102-104
6,8-Dimethoxy-3-[2-(4-methoxyphenyl)ethyl]isocoumarin was synthesized by condensation of 5,7-dimethoxyhompophthalic acid with 3-(4-methoxyphenyl)propanoyl chloride. The structure of the synthesized compound was confirmed by its mass spectrometric studies. The synthesized compound serves as a model for synthesis of DL-agrimonolide. 相似文献
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