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81.
Dung T. Tran Ian P. Jones Jon A. Preece Roy L. Johnston Coenraad R. van den Brom 《Journal of nanoparticle research》2011,13(9):4229-4237
Dodecanethiol-capped Cu–Au nanoparticles, synthesized via a successive two-phase (water/toluene) and galvanic-exchange procedure,
were characterized using transmission electron microscopy (TEM). The size range of the particles is around 1–7 nm. Electron-induced
morphological evolution was observed under high resolution (HR) TEM. Cuboctahedral morphology was found to be thermodynamically
stable. Electron-induced aggregation of two particles was also observed. Chemical ordering of cuboctahedral particles was
studied by atomic-resolution high angle annular dark field (HAADF) imaging in scanning TEM (STEM) mode and energy dispersive
X-ray (EDX) element mapping using a silicon drift detector (SDD). The particles were found to be Cu–Au mixed, and to be stable
in air. Surface plasmon resonance (SPR), which is dependent on local structure and morphology, was investigated by electron
energy loss spectroscopy (EELS). 相似文献
82.
We consider the Sel’kov model of glycolytic oscillator for a quantitative study of the limit cycle oscillations in the system.
We identify a region of parameter space where perturbation theory holds and use both Linstedt Poincaré technique and harmonic
balance to obtain the shape and frequency of the limit cycle. The agreement with the numerically obtained result is excellent.
We also find a different extreme, where the limit cycle is of the relaxation oscillator variety, has a large time period and
it is seen that, as a particular parameter in the model is varied, the time period increases indefinitely. We characterize
this divergence numerically. A calculational method is devised to capture the divergence approximately. 相似文献
83.
The ferromagnetic shape memory alloy with nominal composition Ni54Fe19Ga27 is investigated by Ac susceptibility and resistivity measurements. The alloy shows long-range ferromagnetic order below 290 K. The anomaly due to the martensitic transition is observed in the susceptibility and resistivity data in the temperature range around 220 K, which is associated with clear thermal hysteresis. Minor hysteresis loop technique was used to investigate the phase coexistence across the martensitic transition, and our analysis indicate that both martensite and austenite phases mutually coexist in the region of hysteresis. 相似文献
84.
Uniaxial systems often form labyrinthine domains that exhibit short-range order but are macroscopically isotropic and would not be expected to exhibit precise symmetries. However, their underlying frustration results in a multitude of metastable configurations of comparable energy, and driving such a system externally might lead to pattern formation. We find that soft x-ray speckle diffraction patterns of the labyrinthine domains in CoPd/IrMn heterostructures reveal a diverse array of hidden rotational symmetries about the magnetization axis, thereby suggesting an unusual form of emergent order in an otherwise disordered system. These symmetries depend on applied magnetic field, magnetization history, and scattering wave vector. Maps of rotational symmetry exhibit intriguing structures that can be controlled by manipulating the applied magnetic field in concert with the exchange bias condition. 相似文献
85.
The low energy J/gf photoproduction cross-section has been studied on the basis of the Pomeron model. To incorporate the discrepancy between experimental data and predictions by conventional models, i.e. the sum of the soft Pomeron with intercept 1.08 and the hard Pomeron with intercept 1.418, a Regge trajectory associated with a scalar meson (f,a) exchange which we call “supersoft” Pomeron, is introduced additionally. To distinguish between the conventional model and this new additional Pomeron, observations related to other polarization observables in upcoming polarized experiments are discussed. 相似文献
86.
Interaction of three waves in a beam-plasma system in a circular cylindrical waveguide is studied. The dispersion relation and the axial growth rate have been obtained. 相似文献
87.
B. Roy 《Acta Mathematica Hungarica》2010,127(3):291-300
Characterizations of some properties of generalized R
0 and R
1 topological spaces by using closure operator defined on a generalized topological space will be given. It is also shown that
many results done in this area in some previous papers can be considered as special cases of our results. 相似文献
88.
J. -E. Augustin G. Cosme F. Couchot B. Dudelzak F. Fulda B. Grelaud G. Grosdidier B. Jean-Marie S. Jullian D. Lalanne V. Lepeltier B. Louis F. Mané C. Paulot R. Riskalla Ph. Roy F. Rumpf G. Szklarz Z. Ajaltouni A. Falvard J. Jousset B. Michel J. C. Montret R. Baldini S. Calcaterra G. Capon D. Bisello G. Busetto S. Limentani M. Nigro L. Pescara M. Posocco P. Sartori L. Stanco DM Collaboration 《Zeitschrift fur Physik C Particles and Fields》1987,36(3):369-376
The radiative decayJ/ψ → γ π+ π? has been studied using the 8.6 millionJ/ψ produced in the DM2 experiment at the DCIe +e? storage rings at Orsay. The π+ π? mass spectrum shows a cleanf 2 (1270) signal, and the possible presence of two other states at thef 2 (1720) andf 4 (2030) masses. For thef 2 (1270), the branching ratio BR(J/ψ →γf)xBR(f→π+ π?) is measured to be (7.50±0.30±1.12)×10?4, and the spin analysis prefers theJ=2 assignment, with helicity parametersx=0.83±0.06 andy=0.01±0.06. The existence of higher mass states is discussed. 相似文献
89.
We consider the Lie-Backlund symmetries and conservation laws of a perturbed KdV equation and NLS equation. The arbitrary coefficients of the perturbing terms can be related to the condition of existence of nontrivial LB symmetry generator. When the perturbed KdV equation is subjected to Painlevé analysisa la Weiss, it is found that the resonance position changes compared to the unperturbed one. We prove the compatibility of the overdetermined set of equations obtained at the different stages of recursion relations, at least for one branch. All other branches are also indicated and difficulties associated them are discussed considering the perturbation parameter to be small. We determine the Lax pair for the aforesaid branch through the use of Schwarzian derivative. For the perturbed NLS equation we determine the conservation laws following the approach of Chen and Liu. From the recurrence of these conservation laws a Lax pair is constructed. But the Painlevé analysis does not produce a positive answer for the perturbed NLS equation. So here we have two contrasting examples of perturbed nonlinear equations: one passes the Painlevé test and its Lax pair can be found from the analysis itself, but the other equation does not meet the criterion of the Painlevé test, though its Lax pair is found in another way. 相似文献
90.
Maurice Roy 《Zeitschrift für Angewandte Mathematik und Physik (ZAMP)》1958,9(5-6):554-569
Zusammenfassung Der Verfasser behandelt die Wirbelstr?mung um Pfeilflügel. Diese Str?mung ist, bei etwas h?heren Anstellwinkeln, gekennzeichnet
durch die Ausbildung einer Singularit?t, die er ?Wickelfl?che? (nappe en cornet) nennt. Die Konfiguration am Rand dieser Wirbelfl?che
wird analysiert. Weiter wird das Bild einer konischen Str?mung für einen unendlichen Delta-Flügel untersucht; dabei wird genauer
auf den Sinn der Singularit?ten eingegangen, die zu den Wirbeln der ?Wickelfl?che? oder den von der Pseudo-Str?mung in einer
Querebene gebildeten Wülsten dieser Fl?che hinzugefügt werden, und die den Charakter von Quellen oder Senken haben.
Der Verfasser diskutiert die Bedeutung der Staupunkte, der Trenn- und Abl?sungs-Linien und legt dar, wie man die Ausbildung
der Wülste und weiter der ?Wickelfl?che? selbst als das Ergebnis des Zusammenfliessens der beiden Grenzschichten von Ober-
und Unterseite auffassen kann, wobei diese letztere zur Oberseite hinüberstr?mt.
Schliesslich wird die Bildung von Gegenwirbeln untersucht.
O. N. E. R. A. (Office national d'études et de recherches aéronautiques). 相似文献