Calculation of the volume dependence of the electron density at the nucleus for the elements Li through Am. Relationship of this volume dependence to the hyperfine field for the elements dissolved in a ferromagnetic host

1983 ◽  
Vol 27 (10) ◽  
pp. 6037-6051 ◽  
Author(s):  
Coin T. Page ◽  
John H. Dale ◽  
Lee Chow ◽  
Joseph N. Farrell ◽  
W. D. Josephson ◽  
...  
2008 ◽  
Vol 272 ◽  
pp. 107-116
Author(s):  
Quan Liu

The Chopelas-Boehler approximation for the volume dependence of the Anderson-Gruneisen parameter along isotherms and the new approximation for the volume dependence of the Anderson-Gruneisen parameter along isobars have been used to study the pressure-volume-temperature relationship for LiF, NaF and CsCl crystals up to a pressure of 90kbar and in the temperature range 298-1073K. The calculated values of compression data and experimental values are found to be in good agreement.


2016 ◽  
Vol 2016 ◽  
pp. 1-7 ◽  
Author(s):  
Tímea R. Kégl ◽  
László Kollár ◽  
Tamás Kégl

The σ-donor properties of various P-donor ligands have been studied at the PBEPBE level of theory, which has proved to be accurate in computing the symmetric carbonyl stretching frequencies in nickel(0)-tricarbonyl complexes containing P-donor ligands. The delocalization index from the QTAIM methodology and the energy component associated with the NOCV deformation density representing the donor interaction give the best correlation with Tolman’s electronic parameters, whereas the electron density at the bond critical point and the Wiberg bond index are connected with the donor strength of the ligands to a lesser extent.


1984 ◽  
Vol 62 (4) ◽  
pp. 396-399 ◽  
Author(s):  
R. A. Dunlap ◽  
S. Jha ◽  
G. M. Julian

Sn hyperfine fields were measured using Mössbauer spectroscopy in the Heusler alloys Rh2MnZ (Z = Ge, Sn). The measurements yielded values of −48 and +31 kOe at 77 K for Sn in Rh2MnGe and Rh2MnSn, respectively. These values showed that in these alloys the Sn hyperfine field decreases with increasing conduction electron density. These results are compared with those obtained for Sn hyperfine fields in X2MnZ and Co2YZ Heusler alloys and are discussed in terms of theoretical predictions.


2011 ◽  
Vol 25 (18) ◽  
pp. 1549-1556 ◽  
Author(s):  
S. K. SRIVASTAVA

In this study, we have examined the various formulations for volume dependence of the Grüneisen ratio, γ. The thermodynamic constraints for γ∞, q∞ and λ∞ have been used to discuss the validity of various relationships. The volume dependence of γ and its derivatives, reported by Stacey and Davis [F. D. Stacey and P. M. Davis, Phys. Earth Planet. Inter.142 (2004) 137–184], are analyzed. The Al'tshuler et al.'s relationship of γ(V), widely used in recent literature, has been found to be inadequate on the variation of λ with compression. The estimates of γ, q and λ are obtained with the combination of generalized free volume theory and reciprocal K-prime equations of state for the Earth's interior.


Paleobiology ◽  
1980 ◽  
Vol 6 (02) ◽  
pp. 146-160 ◽  
Author(s):  
William A. Oliver

The Mesozoic-Cenozoic coral Order Scleractinia has been suggested to have originated or evolved (1) by direct descent from the Paleozoic Order Rugosa or (2) by the development of a skeleton in members of one of the anemone groups that probably have existed throughout Phanerozoic time. In spite of much work on the subject, advocates of the direct descent hypothesis have failed to find convincing evidence of this relationship. Critical points are:(1) Rugosan septal insertion is serial; Scleractinian insertion is cyclic; no intermediate stages have been demonstrated. Apparent intermediates are Scleractinia having bilateral cyclic insertion or teratological Rugosa.(2) There is convincing evidence that the skeletons of many Rugosa were calcitic and none are known to be or to have been aragonitic. In contrast, the skeletons of all living Scleractinia are aragonitic and there is evidence that fossil Scleractinia were aragonitic also. The mineralogic difference is almost certainly due to intrinsic biologic factors.(3) No early Triassic corals of either group are known. This fact is not compelling (by itself) but is important in connection with points 1 and 2, because, given direct descent, both changes took place during this only stage in the history of the two groups in which there are no known corals.


1994 ◽  
Vol 144 ◽  
pp. 82
Author(s):  
E. Hildner

AbstractOver the last twenty years, orbiting coronagraphs have vastly increased the amount of observational material for the whitelight corona. Spanning almost two solar cycles, and augmented by ground-based K-coronameter, emission-line, and eclipse observations, these data allow us to assess,inter alia: the typical and atypical behavior of the corona; how the corona evolves on time scales from minutes to a decade; and (in some respects) the relation between photospheric, coronal, and interplanetary features. This talk will review recent results on these three topics. A remark or two will attempt to relate the whitelight corona between 1.5 and 6 R⊙to the corona seen at lower altitudes in soft X-rays (e.g., with Yohkoh). The whitelight emission depends only on integrated electron density independent of temperature, whereas the soft X-ray emission depends upon the integral of electron density squared times a temperature function. The properties of coronal mass ejections (CMEs) will be reviewed briefly and their relationships to other solar and interplanetary phenomena will be noted.


Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.


Author(s):  
Corazon D. Bucana

In the circulating blood of man and guinea pigs, glycogen occurs primarily in polymorphonuclear neutrophils and platelets. The amount of glycogen in neutrophils increases with time after the cells leave the bone marrow, and the distribution of glycogen in neutrophils changes from an apparently random distribution to large clumps when these cells move out of the circulation to the site of inflammation in the peritoneal cavity. The objective of this study was to further investigate changes in glycogen content and distribution in neutrophils. I chose an intradermal site because it allows study of neutrophils at various stages of extravasation.Initially, osmium ferrocyanide and osmium ferricyanide were used to fix glycogen in the neutrophils for ultrastructural studies. My findings confirmed previous reports that showed that glycogen is well preserved by both these fixatives and that osmium ferricyanide protects glycogen from solubilization by uranyl acetate.I found that osmium ferrocyanide similarly protected glycogen. My studies showed, however, that the electron density of mitochondria and other cytoplasmic organelles was lower in samples fixed with osmium ferrocyanide than in samples fixed with osmium ferricyanide.


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