Magnetism of fcc/fcc, hcp/hcp twin and fcc/hcp twin-like boundaries in cobalt

The magnetic moments of the fcc/fcc, hcp/hcp twin and fcc/hcp twin-like boundaries in cobalt were investigated by first-principles calculations based on density functional theory. The magnetic moments in fcc/fcc were larger than those of the bulk fcc, while the variations in the magnetic moment were complicated in hcp/hcp and fcc/hcp. The magnetovolume effect on the magnetic moment at the twin(-like) boundaries was investigated in terms of the local average atomic distance and the average deviation from equilibrium; however, the complicated variations in the magnetic moment could not be explained from the magnetovolume effect. Next, the narrowing (or broadening) of the partial density of states (PDOS) width of 3d orbitals, the number of occupied states for the spin-down channel, and the PDOS around the Fermi level were investigated. The entire variation in the magnetic moment at the twin(-like) boundaries could be understood in terms of these factors. Charge transfer occurred in hcp/hcp. In this case, the contributions of 4s and 4p electrons to the variation in the magnetic moment were relatively large.     

C M ? C N D -computable state

The notions of D-computable state and D-concurrence are generalized to the C ^M ⊗ C ^N system. A class of D-computable state on C ^M ⊗ C ^N is given and the calculating method of the lower bound of D-concurrence is provided. The obvious expression of the lower bound of D-concurrence for the state mixed by two D-pure states is derived. Supported by the National Natural Science Foundation of China (Grant No. 60433050) and the Key Project of the Science Foundation of Xuzhou Normal University (Grant No. 06XLA05)     

Selectron pair production at e - e - and e + e - colliders with polarized beams

We investigate selectron pair production and decay in e ^- e ^- scattering and e ⁺ e ^- annihilation with polarized beams taking into account neutralino mixing as well as initial state radiation and beamstrahlung corrections. One of the main advantages of having both modes at disposal is their complementarity concerning the threshold behavior of selectron pair production. In e ^- e ^- the cross sections at threshold for and increase proportional to the momentum of the selectron and in e ⁺ e ^- that for . Measurements at threshold with polarized beams can be used to determine the selectron masses precisely. Moreover we discuss how polarized electron and positron beams can be used to establish directly the weak quantum numbers of the selectrons. We also use selectron pair production to determine the gaugino mass parameter M₁. This is of particular interest for scenarios with non-universal gaugino masses at a high scale resulting in at the electroweak scale. Moreover, we consider also the case of non-vanishing selectron mixing and demonstrate that it leads to a significant change in the phenomenology of selectrons. Received: 30 January 2002 / Published online: 8 May 2002     

Study on B → φK * and B d → φK S decays in a flavor changing Z′ model

We study the polarization anomaly of the B _d → φK ^*0 decay and the time-dependent CP asymmetry S _φKS of the B _d → φK _S decay in a Z′ model associated with flavor changing neutral currents at the tree level. We obtain the results of 0.0113 < ξ < 0.0127 and 0.0226 < ξ < 0.0255 for the two decay processes when setting ξ _LL = ξ _RL = ξ _LR = ξ _RR = ξ, ξ _LL = ξ _RL = ξ, and ξ _LR = ξ _RR = 0, respectively. These results are consistent with the constraints and assumptions on the model parameters in some references. Supported by the National Natural Science Foundation of China (Grant No. 10575029), the Natural Science Foundation of Henan Province of China (Grant No. 0611050300), the Natural Science Foundation of Henan Provincial Educational Committee (Grant No. 2007140013), and the High-qualified Talents Scientific Research Startup Foundation of Nanyang Normal University (Grant No. nytc2006k92)     

Sea return atC andKu bands

Summary Differences in radar backscattering observed with fan beam Doppler airborne ccatterometers inC andKu band, flown over crude oil artificial spills, are presented as proof that inKu band the mechanism of sea, clutter is due to the second-order Bragg term.

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Riassunto La differenza di eco del mare, osservato con radar doppler con lunghezza d'onda di 5.3 cm e 2.3 cm montati su un aereo sorvolante una macchia di nafta greggia, è proposta come prova che il meccanismo responsabile dell'eco radar del mare a 2.3 cm è dovuto al secondo ordine di Bragg.

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Резюме Исследуются различия в обратном рассеянии радарного сигнала в С-и Кц-зонах от поверхности разлитой сырой нефти. Доказывается, что в Кц-зоне механизм морских помех обусловлен членом Брэгга второго поряцка.

     

Integrable string models with constant torsion in terms of chiral invariants of SU(n), SO(n), SP(n groups

We used the invariant local chiral currents of principal chiral models for SU(n), SO(n), SP(n) groups to construct new integrable string equations of hydrodynamic type on the Riemann space of the chiral primitive invariant currents and on the chiral nonprimitive Casimir operators as Hamiltonians.     

Kaluza-Klein Cosmological Model in f(R,T) Gravity

A five dimensional Kaluza-Klein space-time is considered in the presence of perfect fluid source in f(R,T) gravity proposed by Harko et al. ( [gr-qc], 2011). A cosmological model with a negative constant deceleration parameter with an appropriate choice of a function f(T) is presented. To find a determinate solution of the field equations it is assumed that scalar of expansion is proportional to the shear scalar of the space time. The physical behavior of the model is also studied.     

Slepton production at e + e - and e - e - linear colliders

High-precision analyses are presented for the production of scalar sleptons, selectrons and smuons in supersymmetric theories, at future e ⁺ e^- and e^-e^- linear colliders. Threshold production can be exploited for measurements of the selectron and smuon masses, an essential ingredient for the reconstruction of the fundamental supersymmetric theory at high scales. The production of selectrons in the continuum will allow us to determine the Yukawa couplings in the selectron sector, scrutinizing the identity of the Yukawa and gauge couplings, which is a basic consequence of supersymmetry. The theoretical predictions are elaborated at the one-loop level in the continuum, while at threshold non-zero width effects and Sommerfeld rescattering corrections are included. The phenomenological analyses are performed for e ⁺ e^- and e^-e^- linear colliders with energy up to about 1 TeV and with high integrated luminosity up to 1 ab^-1 to cover the individual slepton channels separately with high precision.Received: 21 October 2003, Revised: 12 January 2004, Published online: 23 April 2004     

Magnetic order in M2Mo3O8 single crystals (M = Mn, Fe, Co, Ni)

Magnetic measurements on hexagonal single crystals of M₂Mo₃O₈ (M = Mn, Fe, Co and Ni) are reported. The Mn compound orders ferrimagnetically at T_c = 41.5 K; the Fe and Co compounds antiferrimagnetically at T_N = 59.5 K and 40.8 K, respectively. No magnetic ordering was found in the Ni compound down to 2 K. All the compounds showed strong magnetic anisotropy when ordered, the results indicating that the magnetic spins' preferred orientation is along the hexagonal axis. Mn₂Mo₃O₈ shows a temperature dependence of the spontaneous magnetization in the ferrimagnetic regime which is rarely observed: as T → 0, M_s → 0.     

Extended q -euler numbers and polynomials associated with fermionic p -adic q -integral on Z p

The purpose of this paper is to construct extended q-Euler numbers and polynomials related to fermionic p-adic q-integral on ℤ _p . By evaluating a multivariate p-adic q-integral on ℤ _p , we give new explicit formulas related to these numbers and polynomials.     

K(m,n,P)方程多-Compacton相互作用的数值研究

采用有限差分法对非线性色散K(m,n,p)方程的多-Compacton之间的相互作用进行了数值研究.该差分方法为二阶精度且线性意义下绝对稳定的无耗散格式,通过添加人工耗散项有效防止了数值解的爆破现象.首先对单-Compacton的长时间演化行为进行了数值模拟,验证了数值方法的有效性.然后对双-CompaCton和三-Compacton的碰撞过程进行了数值研究,发现多-Compacton碰撞之后基本保持碰撞之前的波形和波速,但在波后产生小振幅的Compacton-Anticompacton对.     

Number of states with given spin I and isospin T for n fermions in a j orbit

In this study, we investigate formulas of the number of states with a given total spin I and isospin T for n nucleons in a single-j shell denoted by \begin{document}$ D_{IT} (j, n) $\end{document}. Talmi's recursion formulas for the number of states with a given z-axis projection of total spin are generalized by further considering the isospin couplings and are applied to derive explicit formulas of \begin{document}$ D_{IT} (j, n) $\end{document}.     

On the Q n ? Q p deformation energy surfaces of neutron-rich oxygen isotopes

We present an analysis based on the generator coordinate method that allows one to disentangle the neutron and proton contributions to the properties of low-lying collective states in oxygen isotopes. The text was submitted by the authors in English.     

电子与钠原子散射的S, T, U参数研究

电子原子散射中的S，T，U参数可用来描述散射前后自旋状态的变化，研究精细结构水平上的散射激发振幅之间的关系，进而揭示电子原子碰撞过程中电子自旋-轨道耦合以及电子-电子交换等自旋相关效应.采用扭曲波玻恩近似计算了钠原子受电子散射S→P跃迁中的S，T，U参数，分析了多种入射能(2.2—60 eV)的电子与钠原子激发S→P跃迁过程的S,T,U参数随散射角的分布，其中对10 eV入射能的S_p参数与已报道实验数据符合一致.结果表明，较低能电子入射下的S,T,U参数随散射角的分布幅度和起伏都比较明显，入射能大于40 eV的电子入射，S,T,U参数的散射角分布变化很小. 关键词： 散射激发 S')" href="#">S T')" href="#">T U参数')" href="#">U参数 散射振幅 自旋相关效应     

Electrical and photovoltaic properties of Cd1? x Zn x S/ p -GaAs heterojunctions

Cd_1−x Zn _x S/p-GaAs heterojunctions for solar cell applications have been prepared by growing single crystal Cd_1−x Zn _x S epitaxial layers on (111)GaAs substrates through a vapour phase chemical transport method using the close-spaced geometry and H₂ as a transport agent. Electrical and photovoltaic properties of the heterojunctions have been investigated and discussed in connection with the main features of the growth technique. AM1 power conversion efficiencies up to 6.2% have been measured and possible improvements have been examined.     

Unified (r,s)-Relative Entropy

In this paper, we introduce and study unified (r,s)-relative entropy and quantum unified (r,s)-relative entropy, in particular, our main results about quantum unified (r,s)-relative entropy are established on the infinite dimensional separable complex Hilbert spaces.