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51.
We present a linear rational pseudospectral (collocation) method with preassigned poles for solving boundary value problems. It consists in attaching poles to the trial polynomial so as to make it a rational interpolant. Its convergence is proved by transforming the problem into an associated boundary value problem. Numerical examples demonstrate that the rational pseudospectral method is often more efficient than the polynomial method. 相似文献
52.
We study the stability and the properties of the ground state of neutral systems containing up to four positively charged
bosons and their antiparticles. Examples are the di-pionium molecule (π
+
π
−)2, which is almost identical to the positronium molecule (e
+
e
−)2, the tri-pionium (π
+
π
−)3, and the quadri-pionium (π
+
π
−)4 molecules. We briefly compare our results on the energy to those on the large-N limit of (π
+
π
−)
N
. We also show that the annihilation probability can be calculated accurately with simple wave functions when one uses the
generalized Schwinger rule.
Received September 5, 1994; accepted for publication October 15, 1994 相似文献
53.
54.
Richard Valenta 《Czechoslovak Journal of Physics》1998,48(9):1035-1048
The purpose of this paper is to solve the coupled non-homogeneous equations derived from the basic classical theory of the
acoustic propagation in visco-thermal fluid. The 1D radial distribution of pressure and temperature inside a spherical object
was found. It is supposed that both acoustic and thermal conditions on a surface of the object are known. The starting equations
are considered in the time domain and their solution was found without initial conditions for steady harmonic motion. 相似文献
55.
56.
57.
58.
A class of non-mesogenic molecules, which as mixtures exhibit monotropic nematic phases, is described. 相似文献
59.
60.
This paper examines joint storage considerations when both commodities and resources can be stored, e.g., grain and water for irrigation. Results suggest that when separate agencies control public resource and commodity storage, suboptimal storage rules occur unless (i) each agency is sensitive to the policies of the other, (ii) commodity inventories are adjusted in response to prices, and (iii) resource inventories are adjusted in response to both commodity demand and resource supply conditions. For example, the common case where water storage depends on weather and reservoir conditions alone is not sufficiently general. The results imply that water management agencies that tend to be dominated by engineers and hydrological considerations need to incorporate economic considerations into decision processes. 相似文献