共查询到20条相似文献,搜索用时 109 毫秒
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从圆柱坐标系下的Borgnis位函数的齐次标量Helmholtz方程出发,引入慢波驻波概念及其场 表达式,利用Borgnis位函数的边界条件及相邻子区公共界面上的场匹配条件,导出了整腔 结尾的谐振腔链内角向均匀TM模的色散关系及场分布的解析表达式.运用该解析法对实际器 件——四腔渡越管振荡器进行了求解,求得的谐振频率与实验中测得的微波频率一致,求得 的场分布与数值法得到的场分布十分符合.
关键词:
谐振腔链
色散关系
场分布
解析法 相似文献
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用场方法来求解Whittaker方程.将一个场变量取作为其余场变量和时间的函数并对这个函数建立基本偏微方程.如能求得它的完全积分,那么Whittaker方程的解可由解代数方程来得到.
关键词:
场变量
基本偏微分方程
场方法
积分 相似文献
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E. V. Orlenko T. Yu. Latyshevskaya 《Journal of Experimental and Theoretical Physics》1998,86(6):1167-1176
We unify the method of exchange perturbation theory for multicenter systems. For the case of exchange degeneracy in the total
spin of the system we give a secular equation that is more compact and convenient for calculations than those obtained earlier.
On the basis of this formalism we develop an algorithm for calculating the Heisenberg parameter for magnetic materials. Finally,
we calculate the characteristics of antiferromagnetic transitions for the high-T
c
materials La2−x
MeCuO4 and YBa2Cu3O6.
Zh. éksp. Teor. Fiz. 113, 2129–2147 (June 1998) 相似文献
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D. J. J. Farnell J. Richter R. Zinke R. F. Bishop 《Journal of statistical physics》2009,135(1):175-198
In this article, we prove that exact representations of dimer and plaquette valence-bond ket ground states for quantum Heisenberg
antiferromagnets may be formed via the usual coupled cluster method (CCM) from independent-spin product (e.g. Néel) model
states. We show that we are able to provide good results for both the ground-state energy and the sublattice magnetization
for dimer and plaquette valence-bond phases within the CCM. As a first example, we investigate the spin-half J
1–J
2 model for the linear chain, and we show that we are able to reproduce exactly the dimerized ground (ket) state at J
2/J
1=0.5. The dimerized phase is stable over a range of values for J
2/J
1 around 0.5, and results for the ground-state energies are in good agreement with the results of exact diagonalizations of
finite-length chains in this regime. We present evidence of symmetry breaking by considering the ket- and bra-state correlation
coefficients as a function of J
2/J
1. A radical change is also observed in the behavior of the CCM sublattice magnetization as we enter the dimerized phase. We
then consider the Shastry-Sutherland model and demonstrate that the CCM can span the correct ground states in both the Néel
and the dimerized phases. Once again, very good results for the ground-state energies are obtained. We find CCM critical points
of the bra-state equations that are in agreement with the known phase transition point for this model. The results for the
sublattice magnetization remain near to the “true” value of zero over much of the dimerized regime, although they diverge
exactly at the critical point. Finally, we consider a spin-half system with nearest-neighbor bonds for an underlying lattice
corresponding to the magnetic material CaV4O9 (CAVO). We show that we are able to provide excellent results for the ground-state energy in each of the plaquette-ordered,
Néel-ordered, and dimerized regimes of this model. The exact plaquette and dimer ground states are reproduced by the CCM ket
state in their relevant limits. Furthermore, we estimate the range over which the Néel order is stable, and we find the CCM
result is in reasonable agreement with the results obtained by other methods. Our new approach has the dual advantages that
it is simple to implement and that existing CCM codes for independent-spin product model states may be used from the outset.
Furthermore, it also greatly extends the range of applicability to which the CCM may be applied. We believe that the CCM now
provides an excellent choice of method for the study of systems with valence-bond quantum ground states. 相似文献
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G. M. Luke L. P. Le B. J. Sternlieb Y. J. Uemura J. H. Brewer R. Kadono R. F. Kiefl S. R. Kreitzman T. M. Riseman C. L. Seaman Y. Dalichaouch M. B. Maple J. D. Garrett 《Hyperfine Interactions》1991,64(1-4):517-522
We have performed both zero field and high transverse field measurements at dilution refrigerator temperatures on a number of heavy electron systems, examining the superconducting and magnetic properties of these interesting materials. Among the materials studied to date are UBe13, URu2Si2 and U6Fe. The magnetic field penetration depth in the superconducting state of UBe13 is greater than 10000 Å, as no increase in the transverse field relaxation rate is observed belowT c . A sharp increase in the precession frequency is seen, starting atT c . This frequency shift shows little temperature dependence at low temperature; we found no clear evidence for unconventional superconductivity in this material. Zero field measurements in URu2Si2 show the weak antiferromagnetic transition at 17.5 K. Finally, we we found no clear evidence for unconventional superconductivity in this material. Zero field measurements in URu2Si2 show the weak antiferromagnetic transition at 17.5 K. Finally, we have observed relaxation in high transverse field due to the formation of a flux lattice in U6Fe, a material where the electron effective mass is rather lighter than in other heavy fermion systems. The relaxation exhibits a sharp onset atT c=3.9 K, and is flat at low temperatures as expected for a conventional superconductor. 相似文献
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Manganese ferrite nanoparticles with dysprosium (Dy) ions substituted for iron ions have been prepared by using a sol-gel method. Substitution of a small fraction Dy for Fe results in the larger magnetocrystallite anisotropy of MnFe2−xDyxO4 (x=0.2, 0.4) nanoparticles than that of MnFe2O4 nanoparticles. The magnetosrystallite anisotropy was enhanced with the increase in the substituted dysprosium content. Combining the result of Mössbauer spectra with ZFC and FC curves, we know clearly that the Dy substitution can modify the anisotropy of MnFe2O4 nanoparticles for its strong spin-orbital coupling. Through this simple substitution, we can control the magnetosrystallite anisotropy of the magnetic nanoparticles and make good use of the products according as we need. 相似文献
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Z.Lj. Petrovi? Z.M. Raspopovi? J.V. Jovanovi? G. Malovi? J. de Urquijo 《Applied Surface Science》2007,253(16):6619-6640
We review techniques to prepare, evaluate and apply sets of cross section and transport data for negative ions that are required for the modeling of collisional non-equilibrium plasmas used for processing of microelectronic circuits. We collect and discuss the transport coefficients and cross section sets.We have compiled data for negative ions in CF4 and CF4-related negative ions in rare gases. In addition, we consider data for F− and CF3− in rare gases. Furthermore, we analyze the cross sections of halogen negative ions in rare gases and other molecules. This is followed by the data for SF6 related ions in SF6 and in rare gases. The cross section for scattering of O− in O2 has been derived from the transport data and used to make calculations of the transport properties. Finally we give a brief discussion of the availability of the data for H− ions in H2. We have derived cross sections in several cases but the basic aim is to show the basic features of transport coefficients. In particular we discuss the need to represent properly some details such as the non-conservative nature of transport coefficients and the anisotropy of diffusion. Application of approximate theories and representations of cross sections are also discussed. 相似文献
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M.T. Batchelor K.A. Seaton 《The European Physical Journal B - Condensed Matter and Complex Systems》1998,5(3):719-725
On the basis of features observed in the exact perturbation approach solution for the eigenspectrum of the dilute A3 model, we propose expressions for excitations in the dilute A4 and A6 models. Principally, we require that these expressions satisfy the appropriate inversion relations. We demonstrate that they
give the expected E7 and E6 mass spectra, and universal amplitudes, and agree with numerical expressions for the eigenvalues.
Received: 17 February 1998 / Accepted: 30 April 1998 相似文献
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The highly excited vibrational states of asymmetric linear tetratomic molecules are studied in the framework of Lie algebra.
By using symmetric groupU
1(4)U
2(4)⊗U
3(4), we construct the Hamiltonian that includes not only Casimir operators but also Majorana operators M12, M13 and M23, which are useful for getting potential energy surface and force constants in Lie algebra method. By Lie algebra treatment,
we obtain the eigenvalues of the Hamiltonian, and make the concrete calculation for molecule C2HF. 相似文献
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We propose a review of quantitative spectroscopy of polyynes in the infrared and ultraviolet domain focusing on essential spectroscopic parameters for the interpretation of observed spectra in the infrared and ultraviolet domain and for photochemical modeling. We point at the lacking data in both wavelength domains for C2H2, C4H2, C6H2, C8H2 and propose downloadable files of the ultraviolet absorption coefficient ready to use for photolysis rate calculations. For longer polyynes, we calculate extrapolated ultraviolet spectra and calculate their photolysis rate. Using a simplified photochemical model of the polyynes in Titan and CRL618, we predict their relative abundance and compare them with the observed ones. This also leads us to predict the abundances of the longer polyynes. 相似文献
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ABSTRACT Here we discuss the spin–orbit splitting difference in the 2F7/2 and 2F5/2 ground state of Ce3+-activated XMg2Al16O27(X?Ba, Sr) phosphors. Recently we reported the optical properties in these host materials for the SSL purpose; there was no more literature available to date on these phosphor compositions. By using Gaussian curve fit analysis, we have estimated the energy level difference in the ground state of Ce3+ and the corresponding Stokes shift, and we compare these with those observed in previously reported works in different families of Ce3+-activated oxide-based phosphors. 相似文献
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Bernoulli-p thinning has been well-studied for point processes. Here we consider three other cases: (1) sequences (X 1,X 2,??); (2) gaps of such sequences (X n+1?X 1) n???; (3) partition structures. For the first case we characterize the distributions which are simultaneously invariant under Bernoulli-p thinning for all p??(0,1]. Based on this, we make conjectures for the latter two cases, and provide a potential approach for proof. We explain the relation to spin glasses, which is complementary to important previous work of Aizenman and Ruzmaikina, Arguin, and Shkolnikov. 相似文献