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排序方式: 共有59条查询结果,搜索用时 578 毫秒
1.
系统设计工程师越来越重视功耗问题。原因是系统整体功耗现在受制于各种更严格的功率限制、规范和标准。功率预算的多少将关系到产品的使用寿命、可靠性,以及产品是否满足各种标准的问题。 相似文献
2.
Transgressive dune fields, which are active sand areas surrounded by vegetation, exist on many coasts. In some regions like in Fraser Island in Australia, small dunes shrink while large ones grow, although both experience the same climatic conditions. We propose a general mathematical model for the spatiotemporal dynamics of vegetation cover on sand dunes and focus on the dynamics of transgressive dunes. Among other possibilities, the model predicts growth parallel to the wind with shrinkage perpendicular to the wind, where, depending on geometry and size, a transgressive dune can initially grow although eventually shrink. The larger is the initial area the slower its stabilization process. The model’s predictions are supported by field observations from Fraser Island in Australia. 相似文献
3.
Leal Allan M. M. Kyas Svetlana Kulik Dmitrii A. Saar Martin O. 《Transport in Porous Media》2020,133(2):205-206
Transport in Porous Media - In the original publication of the article, Table 2 was published incorrectly. 相似文献
4.
Aarne Kasikov Alar Gerst Arvo Kikas Leonard Matisen Agu Saar Aivar Tarre Arnold Rosental 《Central European Journal of Physics》2009,7(2):356-362
The resistive response of atomic layer deposited thin epitaxial α-Cr2O3(0 0 1) films, to H2 and CO in air, was studied. The films were covered with Pt nanoislands formed by electron-beam evaporation of a sub-monolayer
amount of the material. The gas measurements were performed at 250°C and 450°C. These temperatures led to different proportion
of chemical states, Pt2+ and Pt4+, to which the Pt oxidized. The modification was ascertained by the X-ray photoelectron spectroscopy method. As a result of
the modification, the response was fast at 250°C, but slowed at 450°C. A disadvantageous abundance of Pt4+ arising at 450°C in air could be diminished by high-vacuum annealing thus restoring the response properties of the system
at 250°C.
相似文献
5.
R. Saar 《Fresenius' Journal of Analytical Chemistry》1930,79(1-2):70-72
Ohne Zusammenfassung 相似文献
6.
R. Saar 《Fresenius' Journal of Analytical Chemistry》1928,73(5-6):242
Ohne Zusammenfassung 相似文献
7.
8.
The nature of surface silanols is reviewed and their influence on retention of basic solutes in reversed phase chromatography is demonstrated and evaluated. The influence of the type of organic modifier and/or pH of buffer on retention of basic analytes with silica based RP columns is evaluated, and means for characterization of RP columns are discussed. Attempts are described to determine the surface silanol concentration of RP columns by chromatographic methods. Surprisingly the experimentally measured silanol concentrations with bare silica and with RP are by one order of magnitude lower than discussed in literature. At pH 7.6 values of 0.12 µmol m?2 have been measured for benzylamine with RP columns, corresponding to about 43% of the measurable silanols of plain silica. The break-through curves of amines let suggest that even at low pH values unprotonated species are present within the pores of the RP stationary phases and their interaction with the bonded alkyl groups contribute to retention. 相似文献
9.
10.
The orthogonal decomposition of the Webster curvature provides us a way to characterize some canonical metrics on a pseudo-Hermitian manifold. We derive some subelliptic differential inequalities from the Weitzenböck formulas for the traceless pseudo-Hermitian Ricci tensor of Sasakian manifolds with constant pseudo-Hermitian scalar curvature and the Chern–Moser tensor of the Sasakian pseudo-Einstein manifolds, respectively. By means of either subelliptic estimates or maximum principle, some rigidity theorems are established to characterize Sasakian pseudo-Einstein manifolds among Sasakian manifolds with constant pseudo-Hermitian scalar curvature and Sasakian space forms among Sasakian pseudo-Einstein manifolds, respectively. 相似文献