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11.
Bohdan Schneider Jan Štokr Pavel Schmidt Marian Mihailov Stoil Dirlikov Nadezhda Peeva 《Polymer》1979,20(6):705-712
Infrared and Raman spectra of atactic PMMA and infrared spectra of stereoregular PMMA and of its four deuterated derivatives , were measured. They were used to assign the bands of stretching and deformation vibrations of CH2, CCH3 and OCH3 groups in the infrared and Raman spectra and to discuss the effect of stereoregularity on these bands in the infrared spectra. 相似文献
12.
Vera S. Chernonosova Alexander A. Gostev Yuriy A. Chesalov Andrey A. Karpenko Alexander M. Karaskov Pavel P. Laktionov 《国际聚合物材料杂志》2019,68(1-3):34-43
AbstractEnsuring long-term functioning and efficient endothelialization of small diameter vascular grafts (VG) is an urgent task of tissue engineering. A solution may be to use electrospun VGs prepared from blends polyurethane with gelatin and/or bivalirudin. Here, properties of 3D matrices were explored by SEM, contact angle measurements and IR spectroscopy, and their interaction with blood and endothelial cells was studied. Introduction of gelatin into matrices enhanced adhesion and proliferation of endotheliocytes and enabled adhesion of platelets, whereas bivalirudin inhibited platelet adhesion while having no negative effect on the adhesion and proliferation of endothelial cells. 相似文献
13.
Pavel P. Fedorov Alexander A. Alexandrov Valery V. Voronov Mariya N. Mayakova Alexander E. Baranchikov Vladimir K. Ivanov 《Journal of the American Ceramic Society》2021,104(6):2836-2848
Phase formation in the SrF2–LaF3 system was studied at temperatures ranging from 300°C to 450°C using nitrate flux. The solubility of LaF3 in SrF2 decreases with decreasing temperature. The equilibrium width of the solid solution region Sr1−xLaxF2+x at 400°C, it is 44.6 ± 0.4 mol% LaF3 (x = 0.446), at 350°C — 38.3 ± 0.7 mol% LaF3 (x = 0.383), and decreases almost to zero at 300°C. 相似文献
14.
Jimmy Lin G. Craig Murray Bonnie J. Dorr Jan Hajič Pavel Pecina 《Language Resources and Evaluation》2009,43(1):27-40
Thesauri and controlled vocabularies facilitate access to digital collections by explicitly representing the underlying principles
of organization. Translation of such resources into multiple languages is an important component for providing multilingual
access. However, the specificity of vocabulary terms in most thesauri precludes fully-automatic translation using general-domain
lexical resources. In this paper, we present an efficient process for leveraging human translations to construct domain-specific
lexical resources. This process is illustrated on a thesaurus of 56,000 concepts used to catalog a large archive of oral histories.
We elicited human translations on a small subset of concepts, induced a probabilistic phrase dictionary from these translations,
and used the resulting resource to automatically translate the rest of the thesaurus. Two separate evaluations demonstrate
the acceptability of the automatic translations and the cost-effectiveness of our approach.
相似文献
Jimmy LinEmail: |
15.
Gregory N. Gol''tsman Ivan G. Goghidze Pavel B. Kouminov Boris S. Karasik Alexei D. Semenov Evgeni M. Gershenzon 《Journal of Superconductivity》1994,7(4):751-755
The transient voltage response in both epitaxial and granular YBaCuO thin films to 80 ps pulses of YAGNd laser radiation of wavelength 0.63 and 1.54 m was studied. In the normal and resistive states both types of films demonstrate two components: a nonequilibrium picosecond component and a bolometric nanosecond one. The normalized amplitudes are almost the same for all films. In the superconducting state we observed a kinetic inductive response and two-component shape after integration. The normalized amplitude of the response in granular films is up to five orders of magnitude larger than in epitaxial films. We interpret the nonequilibrium response in terms of a suppression of the order parameter by the excess of quasiparticles followed by the change of resistance in the normal and resistive states or kinetic inductance in the superconducting state. The sharp rise of inductive response in granular films is explained both by a diminishing of the cross section for current percolation through the disordered network of Josephson weak links and by a decrease of condensate density in neighboring regions. 相似文献
16.
A general model for determining the computational efficiency of a particular class of electro-optical systems is described. The model is an abstraction of parallel systems that use digital electronic processors and optical pipelined buses for communication. Minimum requirements in terms of area (volume for three-dimensional structures) and time necessary in order to solve a problem are obtained. Different applications are investigated, and a matching area-time upper bound is given for the barrel-shift problem, simulated on an array with reconfigurable optical pipelined buses. The types of problems for which these lower bounds seem to be realistic are described. 相似文献
17.
Monoclonal antibodies (MoAbs) against potato virus A (PVA) were examined in their reactivity with PVA and its denatured capsid protein (PVA-CP) bound to the nitrocellulose membrane. Five MoAbs reacted with native PVA, three of them also with PVA-CP. One MoAb gave no reaction in dot-blot test. In polyacrylamide electrophoresis in the presence of sodium dodecyl sulphate (SDS-PAGE) PVA-CP migrated as two major bands. In immunoblot analysis, two MoAbs reacted only with the slower band, one only with the faster one. We presume that those bands do not correspond to the intact CP but they do to truncated N- and C-terminal CP molecules, respectively, and that the corresponding epitopes reacting with MoAbs are localized near to both termini of CP molecules. After mild trypsinolysis of PVA particles no MoAb reacted with resulting "core" CP. 相似文献
18.
Dmitry Lizorkin Pavel Velikhov Maxim Grinev Denis Turdakov 《The VLDB Journal The International Journal on Very Large Data Bases》2010,19(1):45-66
The measure of similarity between objects is a very useful tool in many areas of computer science, including information retrieval.
SimRank is a simple and intuitive measure of this kind, based on a graph-theoretic model. SimRank is typically computed iteratively,
in the spirit of PageRank. However, existing work on SimRank lacks accuracy estimation of iterative computation and has discouraging
time complexity. In this paper, we present a technique to estimate the accuracy of computing SimRank iteratively. This technique
provides a way to find out the number of iterations required to achieve a desired accuracy when computing SimRank. We also
present optimization techniques that improve the computational complexity of the iterative algorithm from O(n
4) in the worst case to min(O(nl), O(n
3/ log2
n)), with n denoting the number of objects, and l denoting the number object-to-object relationships. We also introduce a threshold sieving heuristic and its accuracy estimation
that further improves the efficiency of the method. As a practical illustration of our techniques, we computed SimRank scores
on a subset of English Wikipedia corpus, consisting of the complete set of articles and category links. 相似文献
19.
Online bin stretching is a semi-online variant of bin packing in which the algorithm has to use the same number of bins as an optimal packing, but is allowed to slightly overpack the bins. The goal is to minimize the amount of overpacking, i.e., the maximum size packed into any bin. We give an algorithm for online bin stretching with a stretching factor of \(11/8 = 1.375\) for three bins. Additionally, we present a lower bound of \(45/33 = 1.\overline{36}\) for online bin stretching on three bins and a lower bound of 19/14 for four and five bins that were discovered using a computer search. 相似文献
20.
The present paper deals with the problem of solving the (\(n^2 - 1\))-puzzle and cooperative path-finding (CPF) problems sub-optimally by rule-based algorithms. To solve the puzzle, we need to rearrange \(n^2 - 1\) pebbles in the \(n \times n\)-sized square grid using one vacant position to achieve the goal configuration. An improvement to the existing polynomial-time algorithm is proposed and experimentally analyzed. The improved algorithm represents an attempt to move pebbles in a more efficient way compared to the original algorithm by grouping them into so-called snakes and moving them together as part of a snake formation. An experimental evaluation has shown that the snakeenhanced algorithm produces solutions which are 8–9 % shorter than the solutions generated by the original algorithm. Snake-like movement has also been integrated into the rule-based algorithms used in solving CPF problems sub-optimally, which is a closely related task. The task in CPF consists in moving a group of abstract robots on an undirected graph to specific vertices. The robots can move to unoccupied neighboring vertices; no more than one robot can be placed in each vertex. The (\(n^2 - 1\))-puzzle is a special case of CPF where the underlying graph is a 4-connected grid and only one vertex is vacant. Two major rule-based algorithms for solving CPF problems were included in our study—BIBOX and PUSH-and-SWAP (PUSH-and-ROTATE). The use of snakes in the BIBOX algorithm led to consistent efficiency gains of around 30 % for the (\(n^2 - 1\))-puzzle and up to 50 % in for CPF problems on biconnected graphs with various ear decompositions and multiple vacant vertices. For the PUSH-and-SWAP algorithm, the efficiency gain achieved from the use of snakes was around 5–8 %. However, the efficiency gain was unstable and hardly predictable for PUSH-and-SWAP. 相似文献