Results 251 to 260 of about 3,564,866 (292)

Level-density parameter in natural radioactive nuclei

Modern Physics Letters A, 2022
The intrinsic level-density parameters in natural radioactive nuclei, which emit alpha particles, have been extracted within a microscopic formalism based on the BCS model with inclusion of pairing interaction. Then, total level-density parameters considering the collective effects are obtained. In addition, the level-density parameter excess of total
A. Abyar, R. Razavi
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Density‐Dependent Natural Selection

Ecology, 1971
Density—dependent selective values illustrate the evolutionary effect of population—regulating processes that diminish an individual's probability of survival with increased crowding. The selective values, assumed to decrease as a linear function of density, lead in a mild environment to the evolution of phenotypes having a high carrying capacity, K ...
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Natural Grouping of Population Density

Journal of Geography, 1924
(1924). Natural Grouping of Population Density. Journal of Geography: Vol. 23, No. 1, pp. 32-36.
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Density and Viscosity Measurements of Natural Solutions

Chemistry and Ecology, 1986
Abstract Utilizing sophisticated equipment, densimetric and viscosimetric measurements were carried out on samples of ground-waters of Apulia. Experimental data, utilized to check if simple equations can evaluate the density and the viscosity of multicomponent solutions, confirm the validity of the hypothesis.
POLEMIO M., PROVENZANO M. R., BUFO S., SACCO, ANTONIO   +3 more
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Density-based clustering using approximate natural neighbours

Applied Soft Computing, 2019
Abstract We propose a computationally efficient natural neighbour based metric for discovering clusters of arbitrary shape based on fuzzy measures. The approximate natural neighbours are found with the help of the Choquet integral with respect to a specially designed two-additive fuzzy measure.
Maia Angelova, Gleb Beliakov, Ye Zhu
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Natural densities of Markov transition probabilities

Probability Theory and Related Fields, 1986
Let \((P_ t)\), \((P^*\!_ t)\) be two measurable submarkovian semigroups on a measurable space E which are absolutely continuous and in duality with respect to a \(\sigma\)-finite measure \(\mu\). Then it is shown that there exists a unique measurable function \(p: (0,\infty)\times E\times E\to {\bar {\mathbb{R}}}_+\) satisfying \[ (i)\quad P_ tf(x ...
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Density of Liquefied Natural Gas Components

1978
When measuring cargoes of liquefied natural gas (LNG), knowledge is required of its composition, volume, temperature, and density. It was decided in 1968 to look into the problem of determining LNG density characteristics. Rather than developing a direct-reading densimeter, work was directed toward determining density as a function of composition and ...
J. E. Orrit, J. M. Laupretre
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QTAIM electron density study of natural chalcones

Chemical Physics Letters, 2007
Abstract QTAIM atomic and bond properties, ionization potential, and O–H bond dissociation energies calculated at the B3LYP/6-311++G(2d,2p) level indicate the natural chalcones bear a significant radical scavenging activity. However, their ionization potentials indicate they decrease the electron-transfer rate between antioxidant and oxygen that ...
María J. González Moa, Marcos Mandado, M. Natália D.S. Cordeiro, Ricardo A. Mosquera   +3 more
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The relation between density regulation and natural selection

Proceedings of the Royal Society of London. Series B - Biological Sciences, 1956
Darwin (1859) introduced the notion of natural selection by showing that if the density of a species is to remain steady, most of the individuals in each generation must die prematurely. Nicholson (1954) has analyzed the factors determining the density of a species in great detail. Haldane (1953) did so more summarily. It is simplest to consider annual
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High-Precision Density Determination of Natural Diamonds

Journal of Applied Physics, 1964
Densities of 35 diamonds have been determined by an improved high-precision flotation method. The density varies from ρ25 = 3.51477−3.51554 g/cm3. The average density of 35 samples is ρ25 = 3.51532 g/cm3. The type I diamonds have higher density and narrower range than type II.
R. Mykolajewycz, J. Kalnajs, A. Smakula
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