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排序方式: 共有233条查询结果,搜索用时 62 毫秒
1.
CV Tomy D Pal SS Banerjee S Ramakrishnan AK Grover S Bhattacharya MJ Higgins G Balakrishnan McK Paul 《Pramana》2002,58(5-6):925-935
The weakly pinned single crystals of the hexagonal 2H-NbSe2 compound have emerged as prototypes for determining and characterizing the phase boundaries of the possible order-disorder
transformations in the vortex matter. We present here a status report based on the ac and dc magnetization measurements of
the peak effect phenomenon in three crystals of 2H-NbSe2, in which the critical current densities vary over two orders of magnitude. We sketch the generic vortex phase diagram of
a weakly pinned superconductor, which also utilizes theoretical proposals. We also establish the connection between the metastability
effects and pinning. 相似文献
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3.
Alberti G Brunet E Dionigi C Juanes O de La Mata MJ Rodríguez-Ubis JC Vivani R 《Angewandte Chemie (International ed. in English)》1999,38(22):3351-3353
The hydrophilic oxygen atoms of polyethylenoxide chains inserted as pillars in gamma-zirconium phosphate form hydrogen bonds with the acid groups of the host. As a result the pillars are almost perpendicular to the gamma layers. Upon changing the pH level of the supernatant solution the hydrogen bonds are broken and the pillars become almost perpendicular to the layers (shown schematically). Thus there is a reversible enlargement-shortening of the interlayer space. 相似文献
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J. A. Smith J. F. Winkel A. J. Stace B. J. Whitaker 《Journal of mass spectrometry : JMS》1993,28(5):523-526
A novel instrument which combines high-resolution double-focusing mass spectrometry with time-of-flight detection was applied to the study of cluster ion photofragmentation. Using this apparatus, kinetic energy measurements were made on neutral photofragments following the excitation of Ar at 532 nm. The results show that one and possibly two argon atoms with high centre of mass kinetic energies emerge from the cluster within a few picoseconds of the photon being absorbed. 相似文献
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The efficiency of collisional ionization of excited rubidium atoms is demonstrated for Rb★—Kr collisions. Since the power required to optically saturate the Rydberg levels is much lower than for photoionization, the technique promises to reduce the laser requirements in single-atom detection and other resonance ionizatlon experiments. 相似文献
9.
Bogert D Burnstein R Fisk R Fuess S Morfin J Ohska Stutte L Walker JK Bofill J Busza W Eldridge T Friedman JI Goodman MC Kendall HW Kostoulas IG Lyons T Magahiz R Mattison T Mukherjee A Osborne L Pitt R Rosenson L Sandacz A Tartaglia M Taylor FE Verdier R Whitaker S Yeh GP Abolins M Brock R Cohen A Ernwein J Owen D Slate J Weerts H 《Physical review letters》1985,55(6):574-577
10.
Testing shelled corn for aflatoxin, Part III: evaluating the performance of aflatoxin sampling plans
Johansson AS Whitaker TB Giesbrecht FG Hagler WM Young JH 《Journal of AOAC International》2000,83(5):1279-1284
The effects of changes in sample size and/or sample acceptance level on the performance of aflatoxin sampling plans for shelled corn were investigated. Six sampling plans were evaluated for a range of sample sizes and sample acceptance levels. For a given sample size, decreasing the sample acceptance level decreases the percentage of lots accepted while increasing the percentage of lots rejected at all aflatoxin concentrations, and decreases the average aflatoxin concentration in lots accepted and lots rejected. For a given sample size where the sample acceptance level decreases relative to a fixed regulatory guideline, the number of false positives increases and the number of false negatives decreases. For a given sample size where the sample acceptance level increases relative to a fixed regulatory guideline, the number of false positives decreases and the number of false negatives increases. For a given sample acceptance level, increasing the sample size increases the percentage of lots accepted at concentrations below the regulatory guideline while increasing the percentage of lots rejected at concentrations above the regulatory guideline, and decreases the average aflatoxin concentration in the lots accepted while increasing the average aflatoxin concentration in the rejected lots. For a given sample acceptance level that equals the regulatory guideline, increasing the sample size decreases misclassification of lots, both false positives and false negatives. 相似文献