排序方式: 共有265条查询结果,搜索用时 453 毫秒
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Andrzej Malysa Joanna Wezgowiec Sylwia Orzeszek Wojciech Florjanski Marek Zietek Mieszko Wieckiewicz 《Molecules (Basel, Switzerland)》2021,26(5)
For long-term successful use of ceramic materials in dental procedures, it is necessary to ensure reliable bonding of restorations to dental substrates. This can be achieved by the application of a proper luting cement and through additional surface conditioning. The present systematic review summarizes the most up-to-date evidence on the use of different surface modification methods to enhance the bond strength of dental ceramics to the hard tissues of the teeth. The authors of the review searched the Web of Science, Scopus, and MEDLINE databases to identify relevant articles published between 1 January 2010 and 1 January 2020. A total of 4892 records were identified, and after screening, the full text of 159 articles was evaluated, which finally resulted in the inclusion of 19 studies. The available reports were found to be heterogeneous in terms of materials and methodology, and therefore, only within-studies comparison was performed instead of comparison between studies. A statistically significant difference in the bond strength between the samples treated with different methods of surface conditioning, or between conditioned and nonconditioned samples, was revealed by most of the studies. Predominantly, the studies showed that a combination of mechanical and chemical methods was the most effective way of enhancing bond strength. Artificial aging and luting cement were also identified as the factors significantly influencing bond strength. 相似文献
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Paweł Borowiecki Sylwia Balter Iwona Justyniak Zbigniew Ochal 《Tetrahedron: Asymmetry》2013,24(18):1120-1126
A simple chemoenzymatic synthesis of 1-(9H-fluoren-9-yl)ethanol stereoisomers is described. The enantiomers were resolved by a kinetically controlled transesterification with vinyl acetate in the presence of commercially available lipases. High-throughput screening and subsequent exhaustive investigation of the utility of the lipases in a stereoselective process of introducing chirality have been carried out. Lipase A from Candida antarctica as a cross-linked aggregate (CAL-A-CLEA) was the most efficient enzyme for the resolution of the title compound providing (S)-1-(9H-fluoren-9-yl)ethanol and its (R)-acetate in enantiopure form (>99% ee). Under mild reaction conditions, excellent enantioselectivity (E = 407), and good isolated yields of the products were obtained. 相似文献
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Andrzej G. Chmielewski Yongxia Sun Janusz Licki Andrzej Pawelec Sylwia Witman Zbigniew Zimek 《Radiation Physics and Chemistry》2012,81(8):1036-1039
High concentration of NOx removal from simulated off-gases was investigated using electron beam (EB) technology. Simulated off-gases were prepared by combusting Polish light oil or nature gas with addition of NO from a NO gas cylinder. Irradiation was carried out under a ILU-6 accelerator. It was found that removal efficiency of NOx was influenced by inlet concentration of NO, temperature, SO2 concentration, absorbed dose and irradiation dose rate. Methods of enhancing NOx removal efficiency with additives using EB were also discussed. 相似文献
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Xu Han William A. Cantrell Erika E. Escobar Sylwia Ptasinska 《The European Physical Journal D - Atomic, Molecular, Optical and Plasma Physics》2014,68(3):1-7
Recently demonstrated ghost interference using correlated photons of different frequencies, has been theoretically analyzed. The calculation predicts an interesting nonlocal effect: the fringe width of the ghost interference depends not only on the wave-length of the photon involved, but also on the wavelength of the other photon with which it is entangled. This feature, arising because of different frequencies of the entangled photons, was hidden in the original ghost interference experiment. This prediction can be experimentally tested in a slightly modified version of the experiment. 相似文献
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Decomposition of complete graphs into (0, 2)-prisms 总被引:1,自引:0,他引:1
R. Frucht and J.Gallian (1988) proved that bipartite prisms of order 2n have an α-labeling, thus they decompose the complete graph K 6nx+1 for any positive integer x. We use a technique called the ? +-labeling introduced by S. I. El-Zanati, C. Vanden Eynden, and N. Punnim (2001) to show that also some other families of 3-regular bipartite graphs of order 2n called generalized prisms decompose the complete graph K 6nx+1 for any positive integer x. 相似文献
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We consider a graph Ln, with n even, which is a complete graph with an additional loop at each vertex and minus a 1-factor and we prove that it is edge-disjointly decomposable into closed trails of even lengths greater than four, whenever these lengths sum up to the size of the graph Ln. We also show that this statement remains true if we remove from Ln two loops attached to nonadjacent vertices. Consequently, we improve P. Wittmann’s result on the upper bound of the irregular coloring number c(G) of a 2-regular graph G of size n, by determining that this number is, with a discrepancy of at most one, equal to if all components of G have even orders. 相似文献