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排序方式: 共有304条查询结果,搜索用时 15 毫秒
91.
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93.
Sou Watanabe Ashok K. Adya Leszek Rycerz Adrian C. Barnes Marcelle Gaune-Escard Yoshihiro Okamoto Hiroshi Akatsuka Haruaki Matsuura 《Progress in Nuclear Energy》2005,47(1-4):632-638
Local structural changes in europium dichloride around europium ion at high temperature are evaluated by using X-ray absorption fine structure technique. A distinct phase shift in EXAFS oscillation observed between 700 and 950K arises from Eu2+ to Eu3+ oxidation. Referring to the difference in EXAFS oscillation between oxide and oxychloride of lanthanum, the chemical state of europium on oxidation is identified mainly as Eu2O3. 相似文献
94.
We study deterministic gossiping in ad hoc radio networks with large node labels. The labels (identifiers)
of the nodes come from a domain of size N which may be much larger than the size n of the network (the number of nodes). Most
of the work on deterministic communication has been done for the model with small labels which assumes N = O(n). A notable
exception is Peleg's paper, where the problem of deterministic communication in ad hoc radio networks with large labels is
raised and a deterministic broadcasting algorithm is proposed, which runs in O(n2log n) time for N polynomially large in n. The O(nlog2n)-time deterministic broadcasting algorithm for networks with small labels given by Chrobak et al. implies deterministic
O(n log N log n)-time broadcasting and O(n2log2N log n)-time gossiping in networks with large labels. We propose two new deterministic gossiping algorithms for ad hoc radio
networks with large labels, which are the first such algorithms with subquadratic time for polynomially large N. More specifically,
we propose: a deterministic O(n3/2log2N log n)-time gossiping algorithm for directed networks; and a deterministic O(n log2N log2n)-time gossiping algorithm for undirected networks. 相似文献
96.
Nordström A Tarkowski P Tarkowska D Dolezal K Astot C Sandberg G Moritz T 《Analytical chemistry》2004,76(10):2869-2877
We have developed a method for analyzing polar compounds by reversed-phase LC-ESI-MS following esterification of the analytes' free hydroxyl groups with propionyl or benzoyl acid anhydride. The method was applied to members of the plant hormone group cytokinins, which includes adenine bases, ribosides/glycosides, and nucleotides substituted at N-6 with an isoprenoid side chain, spanning a wide range of polarity. It was also used to analyze other compounds of biological importance, e.g., the nucleotides AMP, ADP, and ATP. The formation of more hydrophobic derivatives had a significant impact on two aspects of the analysis. The retention on a reversed-phase material was greatly increased without the use of any acetate/formate buffer or ion pairing reagent, and the ESI response was enhanced, due to the higher surface activities of the derivatives. Detection limits of propionylated cytokinins were in the high-attomole to low-femtomole range, an improvement by factors of 10-100 compared to previously reported figures. Using an automated SPE-based purification method, 12 endogenous cytokinins were quantified in extracts from 20- to 100-mg samples of leaves (from the plant Arabidopsis thaliana) with high accuracy and precision. Furthermore, the chromatographic properties of the benzoylated AMP, ADP, and ATP in the reversed-phase LC-MS system were much better in terms of retention, separation, and sensitivity than those of their underivatized counterparts, even without the use of any ion pairing reagent. Our data show that derivatization followed by LC-ESI-MS is an effective strategy for analyzing low molecular weight compounds, enabling compounds with a wide range of polarity to be determined in a single-injection LC-MS analysis. 相似文献
97.
WaldemarA. Trzciski Stanisaw Cudzio Leszek Szymaczyk 《Propellants, Explosives, Pyrotechnics》2007,32(5):392-400
Research on the effect of aluminum contents and of its particle size on detonation characteristics of RDX‐based compositions containing 15–60% aluminum was carried out. Measurements of detonation velocity for different charge diameters and confinements were performed. To measure the shock curvature of the detonation wave, X‐ray photography was applied. Unconfined charges and charges confined with a water envelope were tested. The radius of the detonation front curvature was determined. The cylinder test results were the basis for determination of the acceleration ability and energetic characteristics of the detonation products of the mixtures. The Gurney energy describing the acceleration ability was found. The detonation energy of the mixtures tested was also estimated from the cylinder test data. 相似文献
98.
Lech Z. Hasse Sylwia Babicz Leszek Kaczmarek Janusz M. Smulko Vlasta Sedlakova 《Microelectronics Reliability》2014
Noise has been used as a diagnostic tool of surge arrester varistor structures comprising of ZnO grains of various type and size. The physical and electrical properties of the measured samples have been described. In the experimental study, the applied measurement system and the results of noise measurements for the selected structures of varistors designed for the continuous working voltage 280 V, 440 V and 660 V have been presented. Noise properties are related to electrical characteristics of the measured specimens giving more distinctive results than their voltage–current characteristics. It is suggested that the proposed procedure can be applied as an effective non-destructive testing method focused on defects and structural heterogeneity detection in the tested objects to assess their preparation processes. 相似文献
99.
100.
Kropiowska Dorota Mikulski Leszek Szeptyński Paweł 《Structural and Multidisciplinary Optimization》2019,59(5):1581-1598
Structural and Multidisciplinary Optimization - An approximate thickness optimization of a rectangular Kirchhoff-Love plate with variable stiffness under uniform load is performed in this paper.... 相似文献