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41.
J. Hietaniemi E. Ikonen T. Katila J. Lindén I. Tittonen 《Hyperfine Interactions》1990,58(1-4):2451-2455
The influence of high-frequency magnetic modulation on Mössbauer resonance is investigated using the67Zn resonance. A phase-modulation theory theory explaining the experimental results is presented. Implications to magnetic modulation experiments with the57Fe resonance are also discussed. 相似文献
42.
Splitting of Mössbauer lines has been observed in conventional energy domain spectra of Permalloy samples when an external radio frequency (rf) magnetic field was tuned to be in resonance with the separation of Zeeman sublevels of either the ground or the excited state of the57Fe nucleus. Time domain measurements were performed with the frequency of the rf field close to the natural linewidth of the 14.4 keV Mössbauer state. A nonmagnetostrictive magnetically soft Permalloy sample was used in the experiments. 相似文献
43.
Robert Vestberg Christina Nilsson Cesar Lopes Per Lind Bertil Eliasson Eva Malmstrm 《Journal of polymer science. Part A, Polymer chemistry》2005,43(6):1177-1187
The synthesis and characterization of dendron‐coated 2,5‐bis(phenylethynyl)thiophene chromophores are described. The dendrimers were grown divergently on the arylthiophene core with the versatile anhydride of 2,2‐bis(methylol)propionic acid. The arylthiophene core was synthesized with Sonogashira coupling reactions. Structurally well‐defined dendrimers up to the fourth generation were grown, as confirmed by size exclusion chromatography, NMR, and matrix‐assisted laser desorption/ionization time‐of‐flight analysis. The different dendritic substitution did not influence the absorption spectra of the compounds in or near the visible region. Solutions of arylthiophenes had good transparency at wavelengths greater than 400 nm. The dendritic thiophenes exhibited an optical‐power limit at the laser wavelength of 532 nm. However, the magnitude of the optical‐power limit of these compounds was slightly lower than that of a nondendritic arylthiophene with n‐pentyl substituents. © 2005 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 43: 1177–1187, 2005 相似文献
44.
45.
Summary Let (Ω,A) be a measurable space, let Θ be an open set inR
k
, and let {P
θ; θ∈Θ} be a family of probability measures defined onA. Let μ be a σ-finite measure onA, and assume thatP
θ≪μ for each θ∈Θ. Let us denote a specified version ofdP
θ
/d
μ
byf(ω; θ).
In many large sample problems in statistics, where a study of the log-likelihood is important, it has been convenient to impose
conditions onf(ω; θ) similar to those used by Cramér [2] to establish the consistency and asymptotic normality of maximum likelihood estimates.
These are of a purely analytical nature, involving two or three pointwise derivatives of lnf(ω; θ) with respect to θ. Assumptions of this nature do not have any clear probabilistic or statistical interpretation.
In [10], LeCam introduced the concept of differentially asymptotically normal (DAN) families of distributions. One of the
basic properties of such a family is the form of the asymptotic expansion, in the probability sense, of the log-likelihoods.
Roussas [14] and LeCam [11] give conditions under which certain Markov Processes, and sequences of independent identically
distributed random variables, respectively, form DAN families of distributions. In both of these papers one of the basic assumptions
is the differentiability in quadratic mean of a certain random function. This seems to be a more appealing type of assumption
because of its probabilistic nature.
In this paper, we shall prove a theorem involving differentiability in quadratic mean of random functions. This is done in
Section 2. Then, by confining attention to the special case when the random function is that considered by LeCam and Roussas,
we will be able to show that the standard conditions of Cramér type are actually stronger than the conditions of LeCam and
Roussas in that they imply the existence of the necessary quadratic mean derivative. The relevant discussion is found in Section
3.
This research was supported by the National Science Foundation, Grant GP-20036. 相似文献
46.
D. A. Lind 《Israel Journal of Mathematics》1978,30(4):335-338
We prove that an ergodic affine transformation of a compact abelian group is loosely Bernoulli, that is, it can be induced
from a Bernoulli shift. 相似文献
47.
Bethe's small-hole coupling theory is applied to coaxial transmission line to design mode selective directional couplers. By independently sampling the TEM and TE11 modes in coaxial line, harmonic measurements can be performed which would require five or more directional couplers if made in rectangular waveguide. Mode selectivity on the order of 30 dB has been achieved. 相似文献
48.
L. Hildingson W. Klamra Th. Lindblad C. G. Lindén G. Sletten G. Székely 《Zeitschrift für Physik A Hadrons and Nuclei》1991,338(2):125-133
High spin states have been studied in133La via the122Sn (15N, 4ny) fusion evaporation reaction. Bands build on low lying h11/2,g7/2 and d5/2 proton states have been identified. At higher spin a h11/2 neutron alignment is observed. The softness with respect to the triaxial deformation makes the nuclear shape sensitive to the quasiparticle configurations and coexistence between states withy ≈ + 30°,y ≈ ? 30° andy ≦ ? 60° was found. The results have been interpreted using total routhian surface (TRS) model calculations. 相似文献
49.
Summary We have studied the time dependence of M?ssbauer absorption in a magnetically soft sample of Fe18Ni82 permalloy under the influence of a radio-frequency (r.f.) magnetic field. Absorption was measured as a function of the r.f.
field phase at specific gamma-ray energies. We have shown that measuring the time dependence of absorption makes it possible
to differentiate between purely magnetic and magnetoacoustic modulation mechanisms even in cases where clear distinction is
not visible in conventional energy domain spectra.
Paper presented at ICAME-95, Rimini, 10–16 September 1995. 相似文献
50.
The letter introduces a new technique for the generation of a set of polynomial codewords. Each word is generated with a single modulo-2 addition, rather than by using the conventional polynomial multiplication technique. The method is simple to apply and can form the basis for set generation by a minicomputer or microprocessor. 相似文献