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排序方式: 共有112条查询结果,搜索用时 171 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
2.
Three new serratanes were isolated from the nonsaponifiable fraction of western white pine ( Dougl.) bark. The compounds were shown to be 3β-methoxyserrat-14-ene-21α,30-diol (), 3β-methoxyserrat-14-ene-21α, 29-diol (), and 3β-methoxyserrat-14-ene-21β,30-diol (), by a combination of chemical, and spectral methods. 相似文献
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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Kesler Michael S. McGuire Michael A. Conner Ben Rios Orlando Murphy Bart Carter William Henderson Hunter B. Ludtka Gerard M. Kisner Roger A. 《Journal of Thermal Analysis and Calorimetry》2022,147(13):7449-7457
Journal of Thermal Analysis and Calorimetry - A new thermal analysis technique is described that allows measurements to be performed on bulk samples at extreme heating and cooling rates and in high... 相似文献
7.
James P. Kutney Günter Eigendorf Brian R. Worth John W. Rowe Anthony H. Conner Bhimsen A. Nagasampagi 《Helvetica chimica acta》1981,64(4):1183-1207
Eleven new triterpenes with the lanostene-type skeleton were isolated from the benzene extract of western white pine bark. Their structures were determined mainly on the basis of physical and spectral data. 相似文献
8.
Effect of exposure dose on the replication fidelity and profile of very high aspect ratio microchannels in SU-8 总被引:1,自引:0,他引:1
We are interested in using SU-8 dense gratings with very high aspect ratio microchannels as the master mold for fabrication of child molds needed for replication. For such applications, the sidewall taper angle and mask replication fidelity of SU-8 are very important. Increasing the exposure time was experimentally observed to decrease the width of the microchannel and the sidewall angle of SU-8 bars. A new diffraction-refraction-reflection model was also developed. The calculated microchannel width and sidewall angle at high exposure dose agreed well with the experimentally observed values indicating that reflection at the silicon substrate was significant. The larger than calculated actual microchannel width for low exposure dose was shown to be due to leaching of unreacted SU-8 in the developer. Dense gratings of high aspect ratio SU-8 bars separated by high aspect ratio (19.1) microchannels were also demonstrated. 相似文献
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10.
Guided by classical concepts, we define the notion of ends of an iterated function system and prove that the number of ends is an upper bound for the number of nondegenerate components of its attractor. The remaining isolated points are then linked to idempotent maps. A commutative diagram illustrates the natural relationships between the infinite walks in a semigroup and components of an attractor in more detail. We show in particular that, if an iterated function system is one-ended, the associated attractor is connected, and ask whether every connected attractor (fractal) conversely admits a one-ended system. 相似文献