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91.
García-Meca C Hurtado J Martí J Martínez A Dickson W Zayats AV 《Physical review letters》2011,106(6):067402
We experimentally demonstrate a low-loss multilayered metamaterial exhibiting a double-negative refractive index in the visible spectral range. To this end, we exploit a second-order magnetic resonance of the so-called fishnet structure. The low-loss nature of the employed magnetic resonance, together with the effect of the interacting adjacent layers, results in a figure of merit as high as 3.34. A wide spectral range of negative index is achieved, covering the wavelength region between 620 and 806 nm with only two different designs. 相似文献
92.
Katsuhiko Nishimura Wayne D. HutchisonYuta Tajiri Yosikazu IsikawaKeisuke Sato Koichi Kindo 《Physica B: Condensed Matter》2011,406(11):2281-2283
Magnetization measurements were carried out on Pr1−xGdxNi single crystals for x=0.1, 0.2, 0.3 and 0.4 using pulsed magnetic fields up to 55 T and at 4.2 K. For the data observed along the c-axis there are clear indications of transitions, of the combined system of Pr and Gd moments, from a ferrimagnetic to a ferromagnetic state. The observed saturation magnetizations at 55 T and intermediate magnetizations at 1 T were well modeled assuming ferro- and ferri-magnetic structures, respectively. 相似文献
93.
Li Liu Zihao Zhou Qinlin Guo Zhen Yan Yunxi Yao D. Wayne Goodman 《Surface science》2011,605(17-18):L47-L50
The growth and morphology of two-dimensional (2-D) gold islands on a single-layer graphene supported on Ru(0001) have been studied by scanning tunneling microscopy (STM). Our findings show that gold exhibits 2-D structures up to a gold dosage of 0.75 equivalent monolayers, and that these 2-D gold islands are thermally stable at room temperature. Parallel polarization modulation infrared reflection absorption spectroscopic (PM-IRAS) and high resolution electron energy loss spectroscopic (HREELS) studies indicate that carbon monoxide (CO) adsorbs on these 2-D gold islands at 85 K, showing a characteristic CO stretching feature at 2095 cm? 1 for a saturation coverage of CO. The red shift of the CO stretching frequency compared to that on charge neutral gold is consistent with electron transfer from graphene to gold, i.e., an electron-rich gold overlayer. Preliminary data obtained by dosing molecular oxygen onto this CO pre-covered surface suggest that the 2-D gold islands catalyze the oxidation of CO. 相似文献
94.
Christopher Wayne Walker 《Annals of Combinatorics》2014,18(1):149-170
For ${N = 1, 2,\ldots,}$ let S N be a simple random sample of size n = n N from a population A N of size N, where ${0 \leq n \leq N}$ . Then with f N = n/N, the sampling fraction, and 1 A the inclusion indicator that ${A \in S_N}$ , for any ${H \subset A_N}$ of size ${k \geq 0}$ , the high order correlations $${\rm Corr}(k) = E \big(\mathop{\Pi}\limits_{A \in H} ({\bf 1}_A - f_N )\big)$$ depend only on k, and if the sampling fraction ${f_N \rightarrow f}$ as ${N \rightarrow \infty}$ , then $$N^{k/2}{\rm Corr}(k) \rightarrow [f (f - 1)]^{k/2}EZ^{k}, k \,{\rm even}$$ and $$N^{(k+1)/2}{\rm Corr}(k) \rightarrow [f (f - 1)]^{(k-1)/2}(2f - 1)\frac{1}{3}(k - 1)EZ^{k+1}, k \,{\rm odd}$$ where Z is a standard normal random variable. This proves a conjecture given in [2]. 相似文献
95.
Gajath Gunatillake Mirjana Jovovic Wayne Smith 《Journal of Mathematical Analysis and Applications》2014
The operator that takes the function f to ψf°φ is a weighted composition operator. We study numerical ranges of some classes of weighted composition operators on H2, the Hardy–Hilbert space of the unit disc. We consider the case where φ is a rotation of the unit disc and identify a class of convexoid operators. In the case of isometric weighted composition operators we give a complete classification of their numerical ranges. We also consider the inclusion of zero in the interior of the numerical range. 相似文献
96.
Wayne L. Gladfelter 《Surface science》2011,605(13-14):1146
This perspective offers a brief summary of a series of publications that reveal insight into the nucleation of titanium oxide on different surfaces. 相似文献
97.
Javier Gallego David Prez‐Foullerat Francisco Mendicuti Wayne L. Mattice 《Journal of Polymer Science.Polymer Physics》2001,39(12):1272-1281
The ratios of the intensity of excimer and monomer emissions, denoted IE/IM, in poly(N‐vinyl carbazole) and copolymers of N‐vinyl carbazole and methyl methacrylate were measured with steady‐state fluorescence. Measurements were performed in dilute solutions of several fluid solvents at 25 °C and in a solid matrix of poly(methyl methacrylate) at room temperature. The values of IE/IM depended on the nature of the solvent, the emission wavelength, and the copolymer composition. Molecular dynamics simulations were performed for diastereoisomers of 2,4‐di(N‐carbazolyl)pentane and for isotactic and syndiotactic trichromophoric copolymer fragments to assist in the identification of the thermally accessible conformations capable of forming intramolecular excimers and the configurational relationship of the carbazole units in these complexes. Nearest neighbor carbazole groups made the dominant contribution to the excimers. Excimers were more likely in isotactic sequences than in syndiotactic sequences, as was also the case for the low‐energy excimer arising from the complete overlap of two carbazole units. © 2001 John Wiley & Sons, Inc. J Polym Sci Part B: Polym Phys 39: 1272–1281, 2001 相似文献
98.
Tamás KálaiMark R. Fleissner József Jek?Wayne L. Hubbell Kálmán Hideg 《Tetrahedron letters》2011,52(21):2747-2749
New pyrroline nitroxides attached to a terminal acetylenic sulfone, a dibenzocyclooctyne or a cyclooctyne carboxylic acid were synthesized and tested in Cu-free click reactions to conjugate these new spin labels with 4-azido-TEMPO, azidophenylalanine and an azidophenylalanine-containing protein. 相似文献
99.
100.
Vincent Besse Loïc Le Pluart Wayne D. Cook Thi‐Nhàn Pham Pierre‐Jean Madec 《Journal of polymer science. Part A, Polymer chemistry》2013,51(23):5046-5055
Phosphonic acids are known to be useful monomers in dental restorative materials because of their good potential to provide enhanced adhesion to hydroxyapatite and their high hydrolytic stability. In this study, the photopolymerization of phosphonic acid‐based monomer via the camphorquinone (CQ)/ethyl‐4‐(dimethylaminobenzoate) (EDAB) photoredox system is compared with a ternary system composed of iodonium hexafluorophosphate and CQ/EDAB. Photocalorimetry shows that the ternary system does not provide a significant acceleration of the polymerization with either acrylamide or methacrylate phosphonic acids. The complexation of the iodonium by the phosphonic moiety of the acidic monomers leads to a lowered iodonium reactivity and reduced polarizability of the medium and as a consequence limits the rate enhancement effect normally observed by phosphonic acids on the polymerization rate. © 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013 , 51, 5046–5055 相似文献