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41.
42.
Simplified expressions for one-centre electron interaction integrals in general and Slater-Condon parameters as well as repulsion
integrals of the type (aa|aa) in particular have been obtained over Slater-type atomic orbitals. Results calculated using these expressions are in agreement
with those due to other authors. 相似文献
43.
44.
We discuss the production of particles via interaction with the earth’s gravitational field. Explicit calculations are done
for high energy scalars passing through earth’s gravitational field. We show for example, that the width for the scalar processφ→3φ can become comparable with a typical weak decay width at an energy scale of a few TeV. (Similar conclusions can be drawn about
particles that ultimately couple to some scalar field.) We speculate that similar processes may be responsible for many of
the anomalies in the 10–104 TeV experimental data. 相似文献
45.
46.
The transmitted photon spectra of133Ba,22Na,137Cs,54Mn and60Co point sources are measured through different thicknesses of water, concrete and sand. The multiple-scatter peaks observed
in these materials at 60, 90 and 100 keV energies respectively are found to be independent of incident photon energy and thickness
of the medium. 相似文献
47.
Vijay Gupta 《分析论及其应用》2003,19(1):81-88
In the present paper, we introduce Szasz-Durrmeyer-Bezier operators M.,.(f,x) , which generalize the Szasz-Durrmeyer operators. Here we obtain an estimate on the rate of convergence of Mn,a(f,x) for functions of bounded variation. Our result extends and improves that of Sahai and Prasad and Gupta and Pant. 相似文献
48.
49.
Vijay M. Rao Donald G. Mitchell Robert M. Steiner Matthew D. Rifkin D.Lawrence Burk Jr. David Levy Samir K. Ballas 《Magnetic resonance imaging》1988,6(6):661-667
Since considerable expansion of hematopoietic marrow occurs in patients with sickle cell anemia (SCA), magnetic resonance images of 20 hips in 10 patients with known homozygous SCA were reviewed to determine a) if low signal hematopoietic marrow extended into the femoral capital epiphysis and b) if the MR characteristics of avascular necrosis (AVN) differed depending on the type of epiphyseal marrow. Our results revealed variable epiphyseal marrow type; mixed (fatty and hematopoietic) marrow (42%), fatty marrow (32%), hematopoietic marrow (16%) and hemosiderotic marrow (10%). AVN occurred irrespective of the underlying marrow. Segmental areas of low signal intensity in variable shapes (ring, band, crescent or large homogeneous area) was the most consistent MR manifestation of AVN in SCA. A low signal intensity peripheral rim surrounding a central zone, isointense with epiphyseal marrow on T1 and T2 weighted images, was most frequently observed similar to that described in patients without hemoglobinopathy. The notable difference, however, was of segmental areas within the same femoral head that demonstrated variable central zone signal on T2 weighted images. Further, while an increase in hip joint fluid is commonly seen with both early and advanced AVN in patients without hemoglobinopathy; it was increased in only one hip in patients with SCA. The observed differences in MR characteristics may be due to different pathophysiology of AVN in patients with SCA. 相似文献
50.
We have used Ramakrishnan–Yussouff (RY) density functional theory (DFT) to explore the topology of the phase diagram of two-component charge stabilised colloidal suspensions confined to a two-dimensional plane. The particles of the system interact via purely repulsive soft core Yukawa potential. Pair correlation functions (PCFs) used as input informations in DFT were calculated by solving both the hypernetted chain (HNC) and Percus–Yevick (PY) integral equation theories. To test the relative performance of the HNC and PY theories in the context of phase transitions, we have also studied the corresponding one-component systems. We found that RY DFT with HNC PCFs does not stabilise solid in both the one- and two-component cases, whereas the PY theory does. By considering the freezing into the substitutionally disordered triangular solid, we found that the temperature-composition phase diagrams of the binary mixture are narrow spindles whose thickness depends on the symmetry of the mixture components and the value of the screening constant of the Yukawa potential. Although the phase diagram obtained by RY DFT with structural inputs calculated by the PY theory is found to be shifted to higher temperature region in the temperature-composition plane, however, it captures qualitatively all the essential features of the phase diagram. Our results are in principle verifiable through computer simulations and experiments. 相似文献