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91.
A. Veiga N. Martínez P. Mendoza Zélis G. A. Pasquevich F. H. Sánchez 《Hyperfine Interactions》2006,167(1-3):905-909
A prototype of a programmable constant-velocity scaler is presented. This instrument allows the acquisition of partial Mössbauer spectra in selected energy regions using standard drivers and transducers. It can be fully operated by a remote application, thus data acquisition can be automated. The instrument consists of a programmable counter and a constant-velocity reference. The reference waveform generator is amplitude modulated with 13-bit resolution, and is programmable in a wide range of frequencies and waveforms in order to optimize the performance of the transducer. The counter is compatible with most standard SCA, and is configured as a rate-meter that provides counts per selectable time slice at the programmed velocity. As a demonstration of the instrument applications, a partial Mössbauer spectrum of a natural iron foil was taken. Only positive energies were studied in 512 channels, accumulating 20 s per channel. A line width of 0.20 mm/s was achieved, performing with an efficiency of 80%. 相似文献
92.
F. Kulcsár D. Teherani H. Altmann 《Journal of Radioanalytical and Nuclear Chemistry》1982,68(1-2):161-168
It is pessible to study experimentally Cherenkov light spectra in a liquid scintillation spectrometer with colour filters.
Cherenkov light spectra of60Co,198Au,115Cd,143Ce,140La,32P,86Rb,76As,42K and an external standard were studied in a Packard 3375 type liquid scintillation spectrometer, using 11 various Kodak Wratten
filters. The absorption maxima of the filters ware in the 410–796 nm interval. 相似文献
93.
We study dynamic self-reconfiguration of modular metamorphic systems. We guarantee the feasibility of motion planning in a
rectangular model consisting of square modules that are allowed to slide along or rotate about one another. That is, we show
that any two connected configurations of the same number of modules can be transformed into each other by a sequence of moves
so that all intermediate configurations are connected. This settles a conjecture formulated in [6]. 相似文献
94.
A. Ádám 《Acta Mathematica Hungarica》1989,54(3-4):291-296
95.
96.
A. Z. Dubničková S. Dubnička R. Baldini-Ferroli 《Czechoslovak Journal of Physics》1991,41(11):1075-1081
It is shown that all global analyses of nucleon electromagnetic form factor data predict the electron-positron annihilation into neutron-antineutron cross section (for which there are no data till now) to be in a finite energy region substantially larger than the electron-positron annihilation into the proton-antiproton one.Dedicated to the memory of M. Gmitro. 相似文献
97.
Juan E. Nápoles Valdés 《Results in Mathematics》2002,41(3-4):337-345
Qualitative behavior of second order nonlinear differential equations of type y″+p(t)y+q(t)f(y)=0, is studied. It includes properties such as positivity, number of zeros, oscillating nature, boundedness and monotonicity of the solutions. 相似文献
98.
On a recursive method for the estimation of unknown parameters of partially observed chaotic systems
We investigate a recently proposed method for on-line parameter estimation and synchronization in chaotic systems. This novel technique has been shown effective to estimate a single unknown parameter of a primary chaotic system with known functional form that is only partially observed through a scalar time series. It works by periodically updating the parameter of interest in a secondary system, with the same functional form as the primary one but no explicit coupling between their dynamic variables, in order to minimize a suitably defined cost function. In this paper, we review the basics of the method, and investigate its robustness and new extensions. In particular, we study the performance of the novel technique in the presence of noise (either observational, i.e., an additive contamination of the observed time series, or dynamical, i.e., a random perturbation of the system dynamics) and when there is a mismatch between the primary and secondary systems. Numerical results, including comparisons with other techniques, are presented. Finally, we investigate the extension of the original method to perform the estimation of two unknown parameters and illustrate its effectiveness by means of computer simulations. 相似文献
99.
Push-pull dithiafulvenes with reduced bond length alternation (BLA) and high optical nonlinearities have been prepared. The interplay between the proaromaticity of the donor and the structural and optical properties of these merocyanines is discussed. The donor ability of dithiafulvenes can reach that of ferrocene or dialkylaminophenyl groups. 相似文献
100.
György Gát 《Analysis Mathematica》2006,32(1):25-48
Summary It is known that the Fejér means - with respect to the character system of the Walsh, and bounded Vilenkin groups - of an
integrable function converge to the function a.e. In this work we discuss analogous problems on the complete product of finite,
not necessarily Abelian groups with respect to the character system for functions that are constant on the conjugacy classes.
We find that the nonabelian case differs from the commutative case. We prove the a.e. convergence of the (C,1) means of the Fourier series of square integrable functions. We also prove the existence of a function f∊Lq for some q >1 such that sup |σn f | = + ∞ a.e. This is a sharp contrast between the Abelian and the nonabelian cases. 相似文献