共查询到20条相似文献,搜索用时 31 毫秒
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Valeri V. Dvoeglazov 《International Journal of Theoretical Physics》1998,37(7):1909-1914
On the basis of first principles we derive theBarut-Wilson-Fushchich secondorder equation in the (1/2,0) (0, 1/2) representation. Then we discuss thepossibility of describing various mass and spin states in such a framework. 相似文献
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采用基于密度泛函理论的第一性原理方法比较研究了Na1/2Bi1/2TiO3和K1/2Bi1/2TiO3的电子结构、离子位移势能面和Γ声子等性质.结果表明,Na1/2Bi1/2TiO3和K1/2Bi1/2TiO3的电子结构很相似,价带由O 2p电子态主导并包含部分Ti 3d和Bi 6p电子态,导带低能部分由Ti 3d空轨道构成;K取代Na后其Ti—O和Bi—O键的键强略有增加.两者的离子位移势能面也很接近,O离子的偏心位移对结构不稳定性起主导作用,且K取代Na后其作用增强.Γ声子都存在3个软模,分析表明软模主要来自O6基团的振动,K取代Na后A2u软模发生硬化. 相似文献
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A. I. Reznikov S. Ya. Umanskii Yu. F. Chaikina 《Russian Journal of Physical Chemistry B, Focus on Physics》2009,3(2):173-178
The rate constant for the quenching of excited F(2 P 1/2) and Cl(2 P 1/2) atoms in collisions with N2 molecules were calculated. The electron interaction matrix between N2(X 1Σ g + ) and F and Cl atoms in the 2 P j state calculated asymptotically taking into account quadrupole-quadrupole, dispersion, and exchange interactions was used. The dynamic problem of electronic transitions was solved using the modified wave number approximation, the exactly solvable semiclassical exponential nonadiabatic bond model, and the method of phase functions. 相似文献
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本文对2s_(1/2)-1d_(3/2)壳层原子核(A=30—40)能谱作了系统分析,计算仅限于由2s_(1/2)和1d_(3/2)支壳层产生的情态,但考虑了它们之间的全部组态混合效应。计算是采用多粒子壳模型的Talmi方法,将二体矩阵元当作参数,其值由实验确定。文中详细分析了Si~(30),Si~(31),P~(30),P~(31),P~(32),S~(32),Ar~(37),Ar~(38),K~(38)等原子核能谱,理论与实验符合颇好。 相似文献
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C. G. Koutroulos 《International Journal of Theoretical Physics》1986,25(10):1095-1104
A method is given of obtaining the subsidiary conditions of the second kind of the general Gel'fand-Yaglom wave equation based on the representation (1/2, 3/2)(–1/2, 3/2)(1/2, 5/2)(–1/2, 5/2)(1/2, 3/2)(–1/2, 3/2) and in the presence of an external electromagnetic field by reformulating the wave equation in spinor form. The wave equations accepting these subsidiary conditions form a class defined by a set of simultaneous equations that is not empty. 相似文献
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Jiagang Wu Sha Qiao Jianguo Zhu Dingquan Xiao 《Applied Physics A: Materials Science & Processing》2012,109(2):273-277
0.852[Bi1/2(Na1?x Li x )1/2]TiO3?C0.110(Bi1/2K1/2)TiO3?C0.038Ba0.85Ca0.15Ti0.90Zr0.10O3 (BNLT?CBKT?CBCTZ-x) new ternary piezoelectric ceramics were fabricated by the conventional solid-state method, and their piezoelectric properties as a function of the Li content were mainly investigated. A?stable solid solution with a single perovskite structure has been formed, and the depolarization temperature (T d) of these ceramics was identified by using the temperature dependence of the dielectric loss. The T d value of these ceramics gradually decreases, while the T m value increases with increasing the Li content. The dielectric constant increases and the dielectric loss decreases with increasing the Li content, and an enhanced piezoelectric behavior of d 33??223 pC/N and k p??35.2?% has been demonstrated in these ceramics with x=0.06. 相似文献
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Valeri V. Dvoeglazov 《International Journal of Theoretical Physics》1998,37(7):1915-1944
We find a mapping between antisymmetric tensormatter fields and the Weinberg 2(2j + 1)-componentbispinor fields. Equations which describethe j = 1 antisymmetric tensor field coincide with the Hammer-Tucker equations entirely and withthe Weinberg ones within a subsidiary condition, theKlein-Gordon equation. A new Lagrangian for the Weinbergtheory is proposed which is scalar and Hermitian. It is built on the basis of the concept ofWeinberg doubles. The origin of acontradiction between the classical theory, the Weinbergtheorem B – A = for quantum relativisticfields, and the claimed longitudity of the antisymmetrictensor field [transformed on the (1, 0) (0, 1)Lorentz group representation] after quantization isclarified. Analogs of the j = 1/2 Feynman–Dysonpropagator are presented in the framework of the j = 1 Weinberg theory.It is then shown that under a definite choice of fieldfunctions and initial and boundary conditions themassless j = 1 Weinberg–Tucker–Hammerequations contain all the information that the Maxwell equationsfor the electromagnetic field have. Thus, the formerappear to be of use in describing some physicalprocesses. 相似文献
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N. M. Olekhnovich I. I. Moroz A. V. Pushkarev Yu. V. Radyush A. N. Salak N. P. Vyshatko V. M. Ferreira 《Physics of the Solid State》2008,50(3):490-495
The dielectric properties of (1 ? x)Na1/2Bi1/2TiO3-xLaMg1/2Ti1/2O3 solid solutions (0 ≤ x ≤ 0.4) were studied over the temperature range 650–1030 K by measuring the impedance spectra over the frequency range 25–106 Hz. The Curie temperature T C was determined as a function of the composition of the solid solutions. It is shown that T C decreases linearly with increasing x. The temperature dependences of the dc component (σdc) and the polarization component (σ′ac) of the real part of the conductivity are found. The activation energy for the conductivity σdc is shown to increase abruptly as the temperature increases above approximately 770 K for all solid solution compositions. Over the temperature range corresponding approximately to the region of existence of the tetragonal phase of Na1/2Bi1/2TiO3, the polarization component σ′ac of the solid solutions, as well as that of the pure compound, is anomalously high at low frequencies, which can be due to structural inhomogeneities. 相似文献
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Chuanliang Li Lunhua Deng Junli Zhang Xiaohua Yang Yangqin Chen Longsheng Ma 《Journal of Molecular Spectroscopy》2010,260(2):85-87
The near-infrared absorption spectrum of He2 has been recorded in the range of 12 090–13 300 cm−1 using the optical heterodyne concentration modulation spectroscopy. Fifty-nine He2 spectral lines were assigned to the (1, 0), (2, 0), (3, 1) and (4, 2) bands in the c3Σg+–a3Σu+ system and a non-linear least-squares fitting was performed to get the improved molecular constants for the levels (υ = 1, 3 and 4) in the upper electronic state. 相似文献
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XU De-Zhi 《中国物理C(英文版)》1983,7(1):13-19
In this paper we propose an SU(4)×SU(2)×U(1) unified model, in which the stratons and leptons of every generation belong to the same Multiplet, and the leptons will couple to the stratons. But this kind of coupling cannot cause the proton decay, and has only some effects in high energy scatterings. This model predicts the existense of two neutral intermediate bosons, instead of one, and the value of Weinberg angle to be sin2θw=0.25. The neutrinos have reasonable masses in the model. 相似文献
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本文提出了具有非磁性缺陷(n_ml~(1/2)(?)1)的二维 RKKY 自旋玻璃模型,分别推导出高温区和低温区磁化率的表达式,应用渗流理论说明了转变温区磁化率存在尖拐状峰值的实验事实,并讨论了本模型应用的物理条件. 相似文献
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《Current Applied Physics》2009,9(1):249-252
Effects of compressive stress on the ferroelectric properties of ceramics in PZT–PZN system were investigated. The ceramics with a formula (1−x)Pb(Zr1/2Ti1/2)O3–xPb(Zn1/3Nb2/3)O3 or (1−x)PZT–(x)PZN (x = 0.1–0.5) were prepared by a conventional mixed-oxide method. The ferroelectric properties under the compressive stress of the PZT–PZN ceramics were observed at the stress levels up to 170 MPa using a compressometer in conjunction with a modified Sawyer–Tower circuit. It was found that with increasing compressive stress the area of the ferroelectric hysteresis (P–E) loops, the saturation polarization (Psat), the remnant polarization (Pr), and the coercive field (Ec) decreased. These results were interpreted through the non-180° ferroelastic domain switching processes. 相似文献