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941.
ANALYSIS OF DISPERSION CHARACTERISTICS FOR A CIRCULAR DIELECTRIC WAVEGUIDE WITH PERIODIC METALLIC STRIPS 总被引:1,自引:0,他引:1
The dispersion characteristics of a circular dielectric waveguide with periodic metal-lic strips are analyzed by the Galerkin's method.After obtaining the rigorous dispersion equation,the dispersion curves for both TE_(01)and TM_(01)modes are calculated by the improved Newton'smethod.The variations of the normalized center frequency,width and maximum attenuation con-stant of the stopband with the normalized width of the metallic strips are given.The convergenceproperties of numerical solutions are also discussed.On the basis of the analysis,some usefulguidelines for filter design are thereby suggested. 相似文献
942.
943.
Alberto Berretti 《Journal of statistical physics》1985,38(3-4):483-496
We consider an Ising model with random magnetic fieldh
i
and random nearest-neighbor couplingsJ
ij
. The random variablesh
i
andJ
ij
are independent and identically distributed with a nice enough distribution, e.g., Gaussian. We will prove that (i) at high temperature, infinite volume correlation functions are independent on the boundary conditions and decay exponentially fast with probability 1 and (ii) for any temperature with sufficiently strong magnetic field the correlation functions are again independent on the boundary conditions and decay exponentially fast with probability 1. We also prove that the averaged magnetization of the ground state configuration of the one-dimensional Ising model with random magnetic field is zero, no matter how small is the variance of theh
i
. 相似文献
944.
The infinite-range-interaction m-vector spin glass, in the presence of a uniaxial anistropy, as well as of an external magnetic field (both along the same axis), is studied through the replica method. It is shown that the Gabay-Toulouse line, which signals the ordering of the transverse degrees of freedom in the magnetic-field versus temperature plane, exhibits a reentrant behavior. Possible connections with experimental observations are discussed. 相似文献
945.
R. Huang Z. Suo J.H. Prevost W.D. Nix 《Journal of the mechanics and physics of solids》2002,50(5):1011-1027
The present study provides a theoretical framework for the inhomogeneous deformation in metallic glasses. The free volume concentration is adopted as the order parameter, which is a function of position and time. The three processes that can change the local free volume concentration are diffusion, annihilation, and stress-driven creation. The rate functions for free volume generation and plastic flow depend on the underlying microscopic model, but the framework is generally valid for different models. A simple shear problem is solved as an example. A linear stability analysis is performed on the basis of the homogeneous solution. An inhomogeneous solution is obtained with a finite amplitude disturbance to the initial free volume distribution. Numerical simulation shows the development of the inhomogeneous deformation and strain localization. 相似文献
946.
947.
948.
Molybdenum oxide (Mo1-x
O
x
) and ruthenium oxide (RuO2) films were prepared by rf reactive sputtering of Mo or Ru targets in an O2/Ar plasma. Both films exhibit metallic conductivities. The influence of the deposition parameters on the phase that forms
and on the microstructure of Mo1-x
O
x
and RuO2 films is reported. A phase transformation is observed in Mo1-x
O
x
films subjected to heat treatment. The diffusion barrier performance of Mo1-x
O
x
and RuO2 layers interposed between Al and Si is compared. 相似文献
949.
L. Bih L. Abbas M. Azrour Y. El Amraoui A. Nadiri 《Journal of Thermal Analysis and Calorimetry》2005,81(1):57-60
Summary Glasses belonging to the series yA2O-(1-y)[0.25(WO3)2-0.75P2O5] (y=0.10-0.60) are elaborated. DTA experiments reveal that the glass-network of the glasses are broken with increasing of modifier content. EPR spectra show the presence of two signals due to W5+ and Mo5+, as impuritie. The intensity of these EPR centres decreases when the concentration of A2O increases. The variation of Tg upon the modifier content is ascribed to structural changes occurring in the matrix of these glasses. 相似文献
950.
The thermal decomposition process of mixtures of CoC2O4⋅2H2O (COD) or Co(HCOO)2⋅2H2O (CFD) or [Co(NH3)6]2(C2O4)3⋅4H2O (HACOT) with activated carbon was studied with simultaneous TG–DTG–DTA measurements under non-isothermal conditions in argon
and argon/oxygen admixtures. The results show that the thermal decomposition of the studied mixtures in Ar proceeds in the
same manner. It begins with the salt decomposition to Comet+CoO mixture followed by (T>680 K) the simultaneous reduction of CoO to Cometand carbon degasification. The final product of the thermal decomposition of COD-C and CFD-C mixtures, identified by XRD,
is β-Co. Cobalt contents determined in the final products fall in the range 71–78 mass%. The rest is amorphous residual carbon.
In Ar/O2 admixtures the end product is Co3O4 with ash admixture.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献