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121.
本文在文[4]的基础上讨论了双重时序AR(1)-MA(q)模型的相关结构,在不假定白噪声序列为正态的情况下,证明了安鸿志[2]关于模型的相关结构的猜想是正确的,具体地构造了AR(1)-MA(3)模型的相关结构,并与ARMA模型进行了初步的比较,给出了一些抛砖引玉的讨论. 相似文献
122.
研究一维半导体在外电磁场中的光吸收、涉及电子带间的直接跃迁与间接跃迁,考虑了电子-空穴相互作用的激子光吸收,导出一维半导体的光吸收系数公式。 相似文献
123.
Time differential perturbed angular correlation measurements of the 133–482 keVγ-γ cascade of181Ta in Hf-doped YBa2Cu3O7−x
are presented. The181Hf precurser nuclei are incorporated into the sample by thermal neutron irradiation. Two quadrupole interaction frequencies
are observed in the as-irradiated sample:v
Q1=161±10 MHz with intensityf
1=75%, asymmetry parameterη
1=0.32 and damping parameter Λ1=0.42, andv
Q2=1108±40 MHz withf
2=25%,η
2=0.62, and Λ2=0.60. On annealing the sample in air at various temperaturesT
a and quenching to room temperature,f
1 remained nearly constant forT
a<600°C andv
Q1 for all annealing temperatures indicating that these are insensitive to oxygen stoichiometry. This frequency is interpreted
to be due to181Hf substitutingY sites. BeyondT
a=600°C,f
1 increased and reached a constant value of 90% forT
a=800°C. The value ofv
Q2 showed a slight variation between 1086 and 1160 MHz, whilef
2 remained nearly constant at 25% forT
a<600°C. This component is identified to be due to181Hf substituting Cu 1 sites in the Cu-O chains of YBCO. Above 600°Cv
Q2 decreased and reached a value of 808 MHz beyond 750°C. 相似文献
124.
125.
T.R. Saitoh N. Hashimoto G. Sletten R.A. Bark S. Törmänen M. Bergström K. Furuno K. Furutaka G.B. Hagemann T. Hayakawa T. Komatsubara A. Maj S. Mitarai M. Oshima J. Sampson T. Shizuma P.G. Varmette 《The European Physical Journal A - Hadrons and Nuclei》1998,3(3):197-199
High-spin states in 181Ta have been studied via the 176Yb(11B,α2n) reaction at 52 MeV using the PEX array and at 57 MeV using the NORDBALL array, with α-particle detection. The previously
known, Kπ=(7/2)+ ground state band and Kπ=(9/2)− band have been extended to spins (29/2)+ and (31/2)−, respectively. Two new one-quasiparticle bands, the Kπ=(5/2)+ band built on the known (5/2)+ isomer and a Kπ=((1/2)−) band have been observed. Two other rotational bands with three-quasiparticle structure, Kπ=(15/2)− and ((19/2)+ with π(7/2)[404]ν2(1/2)[510](9/2)[624] and π(9/2)[514]ν2(1/2)[510](9/2)[624] configurations, respectively, have been newly observed. The half-life of the Kπ=((19/2)+) bandhead which decays to the head of the (15/2)− band has been measured to be 140(36) ns. However, transitions from the ((19/2)+) state to the (15/2)− band have not been observed.
Received: 26 August 1998 相似文献
126.
S.F. Lienin R. Brüschweiler R.R. Ernst 《Journal of magnetic resonance (San Diego, Calif. : 1997)》1998,131(2):184-190
The viscosity-dependent retarding effect of a polymeric solvent on the rotation of small solute molecules is investigated by13C NMR relaxation measurements. It is found that the relaxation data of 1,3-dibromoadamantane in highly viscous polymeric chlorotrifluoroethene can be explained neither by isotropic nor by realistic anisotropic tumbling in a single environment. The experimental data are rationalized in terms of fast exchange between at least two environments with correlation times differing by up to two orders of magnitude. The study shows that a uniform retardation of molecular tumbling by a polymeric solvent, desirable for shifting the NMR observation window in studies of intramolecular mobility, is not always feasible. 相似文献
127.
The wavelet and harmonic filtering method suggested by Zalevsky and Ouzieli is introduced in this paper and adopted in our volume holographic image recognition system. This composite filter combines several scaled versions of the cascaded wavelet and harmonic filter, obtaining high discrimination ability and wide dynamic range of rotation and scale deformations. Optical experiments are conducted to demonstrate the validity and practicability of the algorithm. To the best of our knowledge, this is the first report of using this algorithm in a volume holographic system. Moreover, the separate correlation approach proposed in this paper greatly simplifies the manufacturing process and reduces the cost of the system. 相似文献
128.
C. Andreoiu D. Rudolph I. Ragnarsson C. Fahlander R.A.E. Austin M.P. Carpenter R.M. Clark J. Ekman R.V.F. Janssens T.L. Khoo F.G. Kondev T. Lauritsen T. Rodinger D.G. Sarantites D. Seweryniak T. Steinhardt C.E. Svensson O. Thelen J.C. Waddington 《The European Physical Journal A - Hadrons and Nuclei》2002,14(3):317-348
High-spin states in 59Cu were populated using the fusion-evaporation reaction 28Si + 40Ca at a beam energy of 122 MeV. The Gammasphere Ge-detector array in conjunction with the 4π charged-particle detector array
Microball allowed for the detection of γ-rays in coincidence with evaporated light particles. The resulting extensive high-spin
decay scheme of 59Cu is presented, which comprises more than 320 γ-ray transitions connecting about 150 excited states. Their spins and parities
have been assigned via directional correlations of γ-rays emitted from oriented states. Average quadrupole moments of rotational
bands have been determined from the analysis of residual Doppler shifts. Shell model calculations in the fp shell are invoked to study some of the low-spin states, while the experimental characteristics of the rotational bands are
analyzed in the configuration-dependent cranked Nilsson-Strutinsky (CNS) approach.
Received: 15 February 2002 / Accepted: 23 April 2002 相似文献
129.
Francesca Aicardi 《Functional Analysis and Other Mathematics》2006,1(2):93-109
We give a recursive method for building X
p
(a,b) for each prime p. Arnold’s triangle is composed of positive integers: for a>1 and 0<b<a, X
p
(a,b) is the degree of the highest power of p dividing the difference of the binomial coefficients C
pa
pb
−C
a
b
.
相似文献
130.
In the present work, ferrites with compositions of (Ni0.27Zn0.64Cux)Fe1.98O4 (x=0.1, 0.2) were prepared by conventional ceramic methods. The relationship between the microstructure and the temperature dependence of relative initial permeability was investigated. It was found that intergranular pores in the ferrites generate large demagnetizing fields, reducing the temperature dependence of the effective anisotropy field Heff, and decreasing the temperature dependence of the relative initial permeability accordingly. However, intragranular pores pin the movement of domain walls. Compared with the permeability induced by domain wall motion, the permeability that resulted from the spin rotation is more sensitive to temperature. As a result, the relative initial permeability of ferrites becomes more sensitive to temperature with increasing micropores within grains. 相似文献