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71.
On a lattice with 2+1-flavor dynamical domain-wall fermions at the physical pion mass,we calculate the decay constants of D_s* , D* ,and φ .The lattice size is 48^3×96 ,which corresponds to a spatial extension of -5.5 fm,with a lattice spacing of a\approx a≈0.114 fm.For the valence light,strange,and charm quarks,we use overlap fermions at several mass points close to their physical values.Our results at the physical point are fD=213(5) MeV, fDs=249(7) MeV, fD*=234(6) MeV, fDs*=274(7) MeV,and fDs=241(9) MeV.The couplings of D* and D_s* to the tensor current( fVT )can be derived from ratios fD*^T/fD*=0.91(4) and fDs*^T/fDs*=0.92(4) ,respectively,which are the first lattice quantum chromodynamics(QCD)results.We also obtain ratios fD*/fD=1.10(3) and fDs*/fDs=1.10(4) ,which reflect the size of heavy quark symmetry breaking in charmed mesons.Ratios fDs/fD=1.16(3) and fDs*/fD*=1.17(3) can be taken as a measure of SU(3)flavor symmetry breaking. 相似文献
72.
The role of Al5Ti3 and h-Al2Ti long-period superstructures on the plastic properties of TiAl at room temperature is investigated on five single crystals with aluminium content comprised between 54.7 at.%, and 62.5 at.%. After annealing at 1200°C for 1?h, the Al5Ti3 superstructure develops in the L10 (γ) matrix upon increasing Al concentration except for Ti–62.5 at.%Al where h-Al2Ti substitutes for Al5Ti3. The CRSS for <110]{111} first increases abruptly with the development of the Al5Ti3-type ordering. Then, the CRSS reaches a plateau at which dislocations assemble in groups of four to prevent extra anti-phase boundary (APB) from being engendered during glide throughout the Al5Ti3 phase. In Ti–62.5 at.%Al, the CRSS for ordinary slip further increases upon the precipitation of h-Al2Ti in the L10 phase, whereas it decreases when the crystal is fully transformed into single-phased Al5Ti3. <101] superlattice dislocations are primarily activated under both the [210] and [1?1?8.6] load orientations irrespective of the Al concentration, but the dislocation microstructure strongly depends on orientation as well as on the degree of Al5Ti3 ordering. In the [210] orientation, the frequency of the decomposition of <101] dislocations into 1/2<110] and 1/2<112] dislocations decreases abruptly with the development of Al5Ti3. This is interpreted in terms of the increased difficulty to move ordinary dislocations. Under the [1?1?8.6] orientation, the density of faulted dipoles diminishes remarkably with the development of Al5Ti3. This is consistent with the transformation of the low energy extrinsic stacking fault of the L10 phase into a higher energy complex extrinsic stacking fault. 相似文献
73.
Reagen Ying‐Tai Su Li‐Ko Chiu Shan‐Wei Weng Ying‐Shiun Chou Raymond Chien‐Chao Tsiang 《Journal of Polymer Science.Polymer Physics》2012,50(4):280-288
White polymeric light‐emitting diode (WPLED) based on a single polymer, poly(3‐hexylthiophene‐alt‐9,9‐dioctylfluorene) (PTAF), has been successfully demonstrated. This conjugated alternating copolymer, PTAF, comprises 50 mol % of 3‐hexylthiophene which is an orange‐red color chromophore and 50 mol % 9,9‐dioctylfluorene which is a bluish‐green color chromophore. It was synthesized by Suzuki cross‐coupling reaction and has a molecular weight of 15,021 and polydispersity of 1.36. Nanocomposite consisting PTAF and graphene nanosheets enhances the optoelectronic properties and the device fabricated with a configuration of ITO/PEDOT:PSS/(PTAF + 1% graphene)/Ca/Al shows two‐color white electroluminescence with CIE 1931 coordinates of (0.28, 0.34). The white luminescence from a single polymer affords the WPLED device a simple structure and low fabrication cost. © 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2011 相似文献
74.
We present in this paper a finite difference solver for Maxwell's equations in non‐staggered grids. The scheme formulated in time domain theoretically preserves the properties of zero‐divergence, symplecticity, and dispersion relation. The mathematically inherent Hamiltonian can be also retained all the time. Moreover, both spatial and temporal terms are approximated to yield the equal fourth‐order spatial and temporal accuracies. Through the computational exercises, modified equation analysis and Fourier analysis, it can be clearly demonstrated that the proposed triple‐preserving solver is computationally accurate and efficient for use to predict the Maxwell's solutions. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
75.
This paper describes the structural properties and electrical characteristics of thin Dy2O3 dielectrics deposited on silicon substrates by means of reactive sputtering. The structural and morphological features of these films after postdeposition annealing were studied by X-ray diffraction and X-ray photoelectron spectroscopy. It is found that Dy2O3 dielectrics annealed at 700 °C exhibit a thinner capacitance equivalent thickness and better electrical properties, including the interface trap density and the hysteresis in the capacitance-voltage curves. Under constant current stress, the Weibull slope of the charge-to-breakdown of the 700 °C-annealed films is about 1.6. These results are attributed to the formation of well-crystallized Dy2O3 structure and the reduction of the interfacial SiO2 layer. 相似文献
76.
Kai HofenSiegfried Weber Chiu Ping Candace ChanPeter Majewski 《Applied Surface Science》2011,257(7):2576-2580
This paper describes three inexpensive and fast analytical methods to characterise grafted particle surfaces. The reaction of silica with (3-aminopropyl)triethoxysilane, (3-mercaptopropyl)trimethoxysilane and N-(phosphonomethyl)iminodiacetic acid hydrate, respectively, leads to NH2-, SO3H- or COOH-functionalised silica, which were characterised by X-ray photoelectron spectrometry and titration in nonaqueous media as well as with two titration methods in a water-based environment. In the work presented, factors influencing the titrations are pointed out and solutions are presented to overcome these limiting factors are shown. 相似文献
77.
78.
[reaction: see text] A dendrimer wherein the branching points are mechanical in nature has been synthesized. It contains two identical covalently linked bis-dendrons and a core unit fused to two rings that encircle the two bis-dendrons. A "threading-followed-by-stoppering" approach is used in the template-directed synthesis of a precursor bis[2]rotaxane, which undergoes stopper exchange four times to yield the dendrimer in which the two bis-dendrons act as stoppers within the two [2]rotaxane subunits. 相似文献
79.
Kwok W. Chiu David Lyons Geoffrey Wilkinson Mark Thornton-Pett Michael B. Hursthouse 《Polyhedron》1983,2(8):803-810
The reduction of WCl4(PMe3)3 by sodium amalgam in presence of phenylacetylene gives W(PMe3)(PhCCH)3 (A). Reduction in presence of methylisocyanide gives W(PMe3)2(MeNC)4 (B), while in presence of excess PMe3 in tetrahydrofuran under hydrogen, WH2Cl2(PMe3)4 (C) is formed. The reaction of WCl2(PMe3)4 with methanol in tetrahydrofuran gives mixtures of WH2Cl2(PMe3)4 and WOC12(PMe3)3 (D).The structures of A, B, and D have been determined by X-ray diffraction. 相似文献
80.
T.W. Chiu 《Nuclear Physics B》1981,181(3):450-460
I derive the correct relationship between the renormalization constants () defined by momentum subtraction. The implications of this relationship are discussed. 相似文献