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51.
R. B. Arellano-Valle H. Bolfarine 《Annals of the Institute of Statistical Mathematics》1996,48(1):111-125
In this paper we investigate some aspects like estimation and hypothesis testing in the simple structural regression model with measurement errors. Use is made of orthogonal parametrizations obtained in the literature. Emphasis is placed on some properties of the maximum likelihood estimators and also on the distribution of the likelihood ratio statistics. 相似文献
52.
Kh. D. Ikramov 《Mathematical Notes》1996,60(6):649-657
LetR be a (real or complex) triangular matrix of ordern, say, an upper triangular matrix. Is it true that there exists a normaln×n matrixA whose upper triangle coincides with the upper triangle ofR? The answer to this question is “yes” and is obvious in the following cases: (1)R is real; (2)R is a complex matrix with a real or a pure imaginary main diagonal, and moreover, all the diagonal entries ofR belong to a straight line. The answer is also in the affirmative (although it is not so obvious) for any matrixR of order 2. However, even forn=3 this problem remains unsolved. In this paper it is shown that the answer is in the affirmative also for 3×3 matrices. 相似文献
53.
Finite <Emphasis Type="Italic">p</Emphasis>-groups with a class of complemented normal subgroups 下载免费PDF全文
Assume G is a finite group and H a subgroup of G. If there exists a subgroup K of G such that G = HK and H ∩ K = 1, then K is said to be a complement to H in G. A finite p-group G is called an NC-group if all its proper normal subgroups not contained in Φ(G) have complements. In this paper, some properties of NC-groups are investigated and some classes of NC-groups are classified. 相似文献
54.
Yuri Kozitsky 《Letters in Mathematical Physics》2000,53(4):289-303
A lattice model of N-dimensional quantum anharmonic oscillators with a polynomial anharmonicity and a ferroelectric pair interaction is considered. For arbitrary N
, correlation inequalities, showing that the temperature Green functions of this model are dominated by the corresponding Green functions of the scalar (N=1) model, are proven. These inequalities are then used to prove that the fluctuations of displacements of particles remain normal at all temperatures provided the model parameters obey a certain condition. In particular this means that the smallest distance between the energy levels of the corresponding one-dimensional isolated oscillator should be large enough or its mass should be small enough. 相似文献
55.
O. Dubos W. Petry J. Neuhaus B. Hennion 《The European Physical Journal B - Condensed Matter and Complex Systems》1998,3(4):447-454
We present inelastic neutron scattering measurements of the low energy and strongly damped phonons in the high temperature
bcc phase of zirconium. These phonons were investigated at different scattering vectors but equivalent phonon wave vectors in different Brillouin zones or along different but equivalent paths in the same Brillouin zone. Neither the observed differences
in intensity nor in line shapes can be explained by the coherent one-phonon scattering law . This leads to an apparent violation of the fundamental symmetry of lattice dynamics. Taking into account the strong anharmonicity
of these phonons, interferences between one- and multi-phonon scattering are held responsible for these effects. Measurements
in different scattering planes reveal that due to the symmetry of the bcc lattice, these effects can only be observed in certain
directions.
Received: 24 December 1997 / Received in final form: 9 March 1998 / Accepted: 19 March 1998 相似文献
56.
H. Lambaré P. Roche S. Balibar H.J. Maris O.A. Andreeva C. Guthmann K.O. Keshishev E. Rolley 《The European Physical Journal B - Condensed Matter and Complex Systems》1998,2(3):381-391
We have studied the nucleation of bubbles in pure superfluid helium-4 at temperatures down to 65 mK. We have found that the
nucleation is a stochastic process, and that at temperatures below 600 mK the nucleation rate is independent of temperature.
These results are consistent with the assumption that the nucleation takes place via quantum tunneling.
Received: 15 November 1997 / Received in final form: 19 December 1997 / Accepted: 22 January 1998 相似文献
57.
V. Gasumyants N. Ageev E. Vladimirskaya V. Kaydanov 《Superlattices and Microstructures》1998,24(6):443-447
We report experimental data on the temperature and concentration dependences of the Nernst coefficient in the normal state for the YBa2Cu3 − xCoxOyceramic samples with increasing Co content up tox = 0.3. The Nernst coefficient is positive, and its value increases almost linearly withx. The temperature dependences ofQhave been analyzed on the basis of a narrow band model, together with data on other transport coefficients. Using a complex quantitative analysis of four transport coefficients, we were able to estimate the carrier mobility and to elucidate a character of the energy dependence of the relaxation time. 相似文献
58.
研究了在含有光学参量放大器的光力学腔中关于弱探测光的光力诱导透明与本征模劈裂的性质.研究发现,光学参量放大器的驱动场相位和非线性增益值的大小对光力诱导透明窗口宽度和本征模劈裂性质有非常重要的影响,特别是当控制光频率工作在光力学红边带下,通过适当调制相位和非线性增益可以实现比空腔时(没有光学参量放大器时)还狭窄的光力诱导透明窗口,此时伴随着陡峭的色散曲线.这些研究结果有利于在光力耦合系统中实现快慢光、光存储等量子信息处理过程. 相似文献
59.
By virtue of the normal ordering of vacuum projector we directly derive some new complicated operator identities, regarding to the generalized Stirling number. 相似文献
60.
在超短超强飞秒SILEX-Ⅰ激光装置上,开展了薄膜靶激光质子加速的实验研究。实验发现激光预脉冲、靶厚度对质子加速有很大的影响。在激光强度3×1018~3×1019W/cm2条件下,采用前表面厚度为3μm铜、后表面镀4μm厚CH靶,质子的最大能量达到3.15 MeV。而对190 nm厚CH膜靶,质子的最大能量为0.54 MeV。初步研究了激光偏振对质子加速的影响,相同激光功率条件下,圆偏振激光加速产生的质子最大能量略低于P偏振打靶。这些结果与靶后鞘层加速机制相一致。 相似文献