In this paper, we study the dynamical behavior for a 4-dimensional reversible system near its heteroclinic loop connecting a saddle-focus and a saddle. The existence of infinitely many reversible 1-homoclinic orbits to the saddle and 2-homoclinic orbits to the saddle-focus is shown. And it is also proved that, corresponding to each 1-homoclinic (resp. 2-homoclinic) orbit F, there is a spiral segment such that the associated orbits starting from the segment are all reversible 1-periodic (resp. 2-periodic) and accumulate onto F. Moreover, each 2-homoclinic orbit may be also accumulated by a sequence of reversible 4-homoclinic orbits. 相似文献
High power red light was generated from a periodically-poled stoichiometric LiTaO3 (PPSLT) by single-pass frequency doubling of a diode-side-pumped, Q-switched Nd:YAG laser at 1319 nm. An average power of
2.4 W of the 660 nm red light was obtained at the fundamental power of ∼5.4 W with the conversion efficiency up to 44.4% and
with low fluctuation down to 2%. The high efficiency and stability at the red output indicate that it is a practical method
to construct a reliable compact red laser.
PACS 42.70.Mp; 42.79.Nv; 42.55.Xi 相似文献
The surface morphology evolution of Ni/W alloys was studied, as a function of the alloy composition. Using the modified plating baths developed in our laboratory recently, electroplated Ni/W alloys with different W content, in the range of 7–67 atom percent (a/o), can be obtained. This was found to lead to different structures, ranging from polycrystalline fcc-Ni type structure to amorphous, followed by orthorhombic with increasing W content in the alloy. Powder XRD was studied to determine the crystal structures. Ex situ STM, AFM and SEM were used to study in detail the surface morphologies of the different alloys, and their evolution with increasing W content.
The important findings are that a mixture of two crystalline forms can give rise to an amorphous structure. Hillocks that are usually a characteristic of epitaxial growth can also exist in the amorphous alloys. Oriented scratches caused by stress can also be formed.
Up to 20 a/o of W is deposited in the alloys in crystalline form, with the fcc-Ni type structure. Between 20 and about 40 a/o an amorphous structure is observed, and above that an orthorhombic crystal structure is seen, which is characteristic of the NiW binary alloy. Careful choice of the composition of the plating bath allowed us to deposit an alloy containing 67 a/o W, which corresponds to the composition NiW2. 相似文献
The present paper deals with the long-time behavior of a class of nonautonomous retarded semilinear parabolic differential equations. When the time delays are small enough and the spectral gap conditions hold, the inertial manifolds of the nonautonomous retard parabolic equations are constructed by using the Lyapunov-Perron method. 相似文献
The degenerate parametric oscillator (DPO) is analyzed with the nonlinear material treated quantum mechanically. The source of squeezing in the DPO is the same as in the two-photon correlated-spontaneous-emission laser (CEL) — the level coherence. In this sense, they are similar. The amount of squeezing in DPO is the same as in the two-photon CEL at two-photon resonance, but the gain in DPO is usually much smaller than that in the two-photon CEL at two-photon resonance. 相似文献
This paper reports the measurement of magnetic properties of the soft magnetic composite material SOMALOYTM 500 in a square sample under different patterns of flux density with 2D magnetic excitations. The test system, principle of measurement, magnetic power loss calculation, and methods of correction for misalignment of H surface sensing coils are presented. The experimental results show that although nominally isotropic, the SOMALOYTM 500 sample exhibits some anisotropy. The results are useful in the design and performance analysis of rotating electrical machines. 相似文献