Packungsdichte und Wertigkeit von Lithium und Natrium unter Druck / Packing Density and Valence of Lithium and Sodium under Pressure

2005 ◽  
Vol 60 (2) ◽  
pp. 139-142 ◽  
Author(s):  
Martin Trömel ◽  
Karlheinz Taxer
Keyword(s):  
Packing Density ◽  
Linear Increase ◽  
Body Centered Cubic ◽  
Volume Changes

The volume changes of lithium and sodium under pressure are discussed with respect to the packing density of the atoms and their valence. In densely packed Li I (bcc), Li II (fcc), and Li III (α-Hg type), valence increases from 1 at ≈ 5 GPa to ≈ 2.5 at 40 GPa. The maximum valence 3 is attained in Li IV (body-centered cubic, 16 atoms per cell, packing density q = 0.965) at 47 GPa. In densely packed Na I (bcc) a linear increase of valence from 1 at ≈ 10 GPa to 2.9 at 65 GPa is found which continues in Na II (fcc) up to 4.1 at 103 GPa.

The Size Range of Volume Change of Melting

2005 ◽  
Vol 475-479 ◽  
pp. 603-606
Author(s):  
H.M. Lu ◽  
Qing Jiang
Keyword(s):  
Volume Change ◽  
Metallic Glasses ◽  
Packing Density ◽  
Design Principle ◽  
Size Range ◽  
Theoretical Data ◽  
Metallic Alloys ◽  
Volume Changes ◽  
Lattice Contraction ◽  
Model Predictions

Through considering the packing density and the lattice contraction, volume changes of elements with different structures DV on melting are modeled. An agreement between the model predictions and the experimental as well as theoretical data is found. Moreover, the alloy design principle for GFA of bulk metallic glasses (BMG) based on the size of DV is also suggested that amorphous metallic alloys will have the best GFA when its packing density approaches that of A2 crystal.

Atomvolumen, Packungsdichte und chemische Bindung in festem Iod unter Druck / Atomic Volume, Packing Density and Chemical Bonding in Solid Iodine under Pressure

2004 ◽  
Vol 59 (1) ◽  
pp. 44-48 ◽  
Author(s):  
Martin Trömel ◽  
Sven Hübner ◽  
Karlheinz Taxer
Keyword(s):  
Crystal Structure ◽  
Packing Density ◽  
Chemical Bonding ◽  
Ambient Pressure ◽  
Atomic Volume ◽  
Free Molecule ◽  
Volume Changes

Abstract The volume changes of solid iodine under pressure are discussed with respect to the packing density of the atoms and to valence. The packing density of solid iodine which is 0.805 under ambient pressure increases to 0.976 in monoatomic iodine-II, 0.993 in iodine-III, and 1 in fcc iodine-IV. Simultaneously, the valence increases from 1 in the free molecule to 1.78 in the crystal structure under ambient pressure, 2.72 - 2.81 in iodine-II, 2.86 - 2.96 in iodine-III, and 3 in fcc iodine-IV. The valence then remains constant up to about 180 GPa and rises moderately to 3.15 at the highest investigated pressure of 276 GPa. Parameters for calculating bond numbers, valences and atomic volumes of densely packed halogens, hydrogen, oxygen, and nitrogen are given.

Atomvolumen und Packungsdichte der Atome in metallischen Elementen Atomic Volume and Packing Density of Atoms in Metallic Elements

2000 ◽  
Vol 55 (12) ◽  
pp. 1137-1140 ◽  
Author(s):  
Sven Hübner ◽  
Martin Trömel
Keyword(s):  
Crystal Structure ◽  
Packing Density ◽  
Maximum Density ◽  
The Body ◽  
Atomic Volume ◽  
Body Centered Cubic ◽  
Sphere Packings ◽  
Metallic Elements ◽  
Bcc Structure ◽  
Cubic Structure

In the body-centered cubic structure and in closest sphere-packings the atoms are arranged to give structures with equal densities. A measure of the packing density of atoms is derived. Several crystal structures of elements, including the bcc structure and the closest sphere packings, represent a state of maximum density in which the atomic volume is characteristic of each element. From any crystal structure of an element its atomic volume in this state can be calculated to a good approximation.

Atomvolumen, Packungsdichte undWertigkeit von Caesium unter Druck Atomic Volume, Packing Density and Valence of Cesium under Pressure

2003 ◽  
Vol 58 (12) ◽  
pp. 1147-1151 ◽  
Author(s):  
Martin Trömel ◽  
Sven Hübner ◽  
Karlheinz Taxer
Keyword(s):  
Packing Density ◽  
Atomic Volume ◽  
Volume Changes ◽  
Valence Electrons

The volume changes of cesium under pressure are discussed with respect to the packing density of the atoms and valence. The element is univalent in densely packed Cs I and Cs II. Valence increases in Cs III (packing density q = 0.973), in Cs IV (q = 0.943), in Cs V (q ≈ 0.99), and in close packed Cs VI. The diminuition of volume beyond ≈15 GPa is caused by this increase only which implies that electrons of the fifth shell act as valence electrons.

Voids in Irradiated Tungsten and Molybdenum

1969 ◽  
Vol 27 ◽  
pp. 190-191
Author(s):  
Robert C. Rau ◽  
Robert L. Ladd
Keyword(s):  
Melting Point ◽  
Fast Neutron ◽  
Neutron Irradiation ◽  
Elevated Temperatures ◽  
Irradiation Temperature ◽  
The Body ◽  
Face Centered Cubic ◽  
Body Centered Cubic ◽  
Cubic Metals ◽  
Face Centered

Recent studies have shown the presence of voids in several face-centered cubic metals after neutron irradiation at elevated temperatures. These voids were found when the irradiation temperature was above 0.3 Tm where Tm is the absolute melting point, and were ascribed to the agglomeration of lattice vacancies resulting from fast neutron generated displacement cascades. The present paper reports the existence of similar voids in the body-centered cubic metals tungsten and molybdenum.

The Cortisol Response to Normal and Nocturnal Awakening

2000 ◽  
Vol 14 (1) ◽  
pp. 24-28 ◽  
Author(s):  
F. Hucklebridge ◽  
A. Clow ◽  
H. Rahman ◽  
P. Evans
Keyword(s):  
Area Under The Curve ◽  
Secretory Activity ◽  
Linear Increase ◽  
Cortisol Response ◽  
The Awakening ◽  
Basal Cortisol ◽  
Free Cortisol ◽  
Main Effect ◽  
Nocturnal Awakening ◽  
Night Awakening

Abstract Free cortisol as measured in saliva increases markedly following awakening. It is not clear, however, whether this is truly a stress-neuroendocrine response to awakening or a manifestation of the hypothalamic-pituitary-adrenal (HPA) circadian cycle. We investigated whether the awakening cortisol response can be generated in the middle of nocturnal sleep, when secretory activity in the HPA axis is low. In a within subject design, salivary cortisol response was measured under three different awakening conditions: (1) awakening at the normal morning awakening time; (2) awakening four hours prior to normal awakening time, and (3) awakening the following morning after interrupted sleep. The overall main effect was a linear increase in free cortisol following awakening with no significant interaction with awakening condition. Cortisol levels, as determined by area under the cortisol curve calculated with reference to zero, did differ by awakening condition. The two morning awakening conditions were comparable but values were lower for night awakening. Area under the curve change (calculated with reference to the first awakening cortisol base value), however, did not distinguish the three awakening conditions. We conclude from these data that there is a clear free cortisol response to awakening for both nocturnal and morning awakening although the absolute levels produced are lower for nocturnal awakening when basal cortisol is low. Nocturnal interruption of sleep did not affect the subsequent morning response.

Volume changes in HgTe upon melting and heating

1997 ◽  
Vol 94 ◽  
pp. 1816-1826 ◽  
Author(s):  
M Glazov ◽  
LM Pavlova ◽  
SV Stankus
Keyword(s):  
Volume Changes

Hippocampal and amygdala volume changes in patients with major depression and healthy controls during a three year follow-up

2005 ◽  
Vol 38 (05) ◽  
Author(s):  
TS Frodl ◽  
T Zetzsche ◽  
G Schmitt ◽  
T Schlossbauer ◽  
MW Jäger ◽  
...  
Keyword(s):  
Major Depression ◽  
Healthy Controls ◽  
Volume Changes ◽  
Amygdala Volume

Investigations of alternative kale management: Production, regrowth and quality from different sowing and defoliation dates

2007 ◽  
pp. 29-33 ◽  
Author(s):  
H.E. Brown ◽  
S. Maley ◽  
D.R. Wilson
Keyword(s):  
Sowing Date ◽  
Linear Increase ◽  
Thermal Time ◽  
Total Production

Gruner kale showed a linear increase (8.0 kg DM/ha per °Cd) in biomass with sowings on 1 October, 3 November and 1 December producing 23, 19 and 17 t DM/ha (respectively) by the 29 May. Regrowth following mid season defoliation was slow (5.3 kg DM/ha per °Cd) reducing total production (relative to undefoliated) by 7.5 and 5.5 t DM/ha for treatments defoliated on the 29 January and 14 March, respectively. Keyworks: defoliation, kale, quality, regrowth, sowing date, thermal time, yield

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