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11.
A computer construction of the Monster is used to prove thatPSL(2, 59) is a subgroup of the Monster. 相似文献
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Yu. V. Belovitskaya I. V. Pekov E. R. Gobechiya N. A. Yamnova Yu. K. Kabalov N. V. Chukanov J. Schneider 《Crystallography Reports》2002,47(2):223-228
The crystal structures of two ancylite specimens from Khibiny massif (the Kola Peninsula, Russia)—ancylite-(Ce) from alkali hydrothermalites (Sr1.01Ca0.02Ba0.01)Σ1.04(Ce0.52La0.28Nd0.11Pr0.04 Sm0.01)Σ0.96(CO3)2(OH0.83F0.13)Σ0.96 · 0.9H2O and ancylite-(Ce) from carbonatites—have (Sr0.80Ca0.05Ba0.01)Σ0.86(Ce0.62La0.40Nd0.09Pr0.03) Σ1.14(CO3)2(OH0.99F0.15)Σ1.14 · 1.0H2O been refined by the Rietveld method. A focusing STOE-STADIP diffractometer with a bent Ge(111) primary monochromator was used (λ MoK α 1 radiation, 2.16° < 2θ < 54.98°; reflection number 237–437). All the computations for ancylite from alkali hydrothermalites were performed within the sp. gr. Pmc21, a = 5.0634(1) Å, b = 8.5898(1) Å, c = 7.2781(1) Å, V = 316.55(1) Å3, R wp = 1.90; the computations for ancylite from carbonatites were performed within the sp. gr. Pmcn, a = 5.0577(1) Å, b = 8.5665(2) Å, c = 7.3151(2) Å, V = 316.94(1) Å3, R wp = 2.38 in the anisotropic approximation of thermal vibrations of cations and oxygen atoms. 相似文献
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B. MacMillan M. Halse M. Schneider L. Fardy Y. H. Chui B. J. Balcom 《Applied magnetic resonance》2002,22(2):247-256
Magnetic resonance imaging has rarely been applied to rigid polymeric materials, due primarily to the strong dipolar coupling and short signal lifetimes inherent in these materials. SPRITE (single point ramped imaging withT 1 enhancement) (B. J. Balcom, R. P. MacGregor, S. D. Beyea, D. P. Green, R. L. Armstrong, T. W. Bremner: J. Magn. Reson. A123, 131–134, 1996) is particularly well suited to imaging solid materials. With SPRITE, the only requirement is thatT 2* be long enough so that the signal can be phase-encoded. The minimum phase encoding time is limited by the maximum gradient strength available and by the instrument deadtime. At present this is usually tens of microseconds and will only improve with refinements in technology. We have used the SPRITE sequence in conjunction with raising the sample temperature to obtain images of rigid polymers that have largely frustrated conventional imaging methods. This approach provides a straightforward and reliable method for imaging a class of samples that, up until now, have been very difficult to image. 相似文献
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Botjan Japelj Simon Re
nik Petra ebaek Branko Stanovnik Jurij Svete 《Journal of heterocyclic chemistry》2005,42(6):1167-1173
A series of alkyl l‐heteroaryl‐1H‐1,2,3‐triazole‐4‐carboxylates 6a‐u were synthesised in four steps from methyl (Z)‐2‐benzyloxycarbonylarmino‐3‐(dimethylamino)prop‐2‐enoate ( 1 ) and heterocyclic amines 2a‐s. Triazoles 6a‐o were tested against antimycobacterial activity. For the most active compound, n‐pentyl 1‐(6‐phenylpyridazin‐3‐yl)‐1H‐1,2,3‐triazole‐4‐carboxylate ( 6n ), minimum inhibitory concentration 3.13 μg/ml was determined. 相似文献
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Unusual current‐voltage characteristics of single crystalline and bicrystalline La0.7Ca0.3MnO3 films
The current‐voltage characteristics of single crystalline and bicrystalline La0.7Ca0.3MnO3 films were measured and analyzed. Several epitaxial films, as well as 45° [001]‐tilt grain boundaries, display current‐voltage characteristics which are asymmetric with respect to polarity reversal of the bias current. One epitaxial film has a polarity dependent resistance of ~340kΩ and of ~670kΩ in forward and in reverse direction, respectively. 相似文献
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Time-resolved electron transport studies on InGaAs/GaAs-QWIPs 总被引:1,自引:0,他引:1
S. Steinkogler H. Schneider R. Rehm M. Walther P. Koidl P. Grant R. Dudek H. C. Liu 《Infrared Physics & Technology》2003,44(5-6):355-361
Due to the short internal response time, quantum-well infrared photodetectors (QWIPs) are interesting for high-speed applications such as heterodyne spectroscopy or laser pulse monitoring. We studied the photocurrent transients of InGaAs/GaAs-QWIPs after irradiation with infrared laser pulses of 250 fs duration. The excitation wavelength of about 9 μm matches the peak wavelength of the QWIP structure. The photocurrent transient consists of two different dynamical components, representing the fast photoionization in the quantum-wells and the slow injection current that compensates the remaining space charge. The investigations of the different components as a function of temperature and bias voltage were performed on a nanosecond time-scale. The experimental separation of the two photocurrent contributions allows us to determine the photoconductive gain. The Fourier transform of the photocurrent transient was compared with other experimental methods including heterodyne detection and microwave rectification. The quantitative agreement between these different measurement techniques is excellent. 相似文献
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Reaction diffusion systems on cylindrical domains with terms that vary rapidly and periodically in the unbounded direction can be analyzed by averaging techniques. Here, using iterated normal form transformations and Gevrey regularity of bounded solutions, we prove a result on exponential averaging for such systems, i.e., we show that traveling wave solutions can be described by a spatially homogenous equation and exponentially small remainders. (© 2007 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim) 相似文献