Present Status of the a Vogadro Constant Determination from Silicon Crystals with Natural Isotopic Composition

2004 ◽  
Author(s):  
K. Fujii ◽  
A. Waseda ◽  
N. Kuramoto ◽  
S. Mizushima ◽  
P. Becker ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Present Status ◽  
Natural Isotopic Composition ◽  
Silicon Crystals ◽  
Constant Determination

The electrical resistivity of lithium-6

1961 ◽  
Vol 263 (1314) ◽  
pp. 407-419 ◽  
Keyword(s):  
Electrical Resistivity ◽  
Isotopic Composition ◽  
Specific Heat ◽  
Room Temperature ◽  
Natural Isotopic Composition ◽  
Square Roots ◽  
Conduction Electrons ◽  
Ionic Mass ◽  
Theoretical Predictions ◽  
Electrical Resistivities

The electrical resistivities of lithium -6 and lithium of natural isotopic composition have been studied between 4°K and room temperature. In addition, their absolute resistivities have been carefully compared at room temperature. These measurements show that the effect of ionic mass on electrical resistivity agrees with simple theoretical predictions, namely, that the properties of the conduction electrons in lithium do not depend on the mass of the ions, and that the characteristic lattice frequencies for the two pure isotopes are in the inverse ratio of the square roots of their ionic masses. A comparison with the specific heat results of Martin (1959, 1960), where the simple theory is found not to hold, indicates the possibility that anharmonic effects are present which affect the specific heat but not the electrical resistivity.

scholarly journals Magnetic properties of the natural and isotope-modified diamond and silicon carbide

2018 ◽  
Vol 185 ◽  
pp. 04007 ◽  
Author(s):  
A.N. Taldenkov ◽  
A.V. Inyushkin ◽  
E.A. Chistotina ◽  
V.G. Ralchenko ◽  
A.P. Bolshakov ◽  
...  
Keyword(s):  
Silicon Carbide ◽  
Magnetic Properties ◽  
Isotopic Composition ◽  
Single Crystals ◽  
High Purity ◽  
Diamagnetic Susceptibility ◽  
Synthetic Diamond ◽  
Paramagnetic Centers ◽  
Natural Isotopic Composition ◽  
Ferromagnetic Component

The magnetic properties of single crystals of synthetic diamond and crystals of silicon carbide were studied. High-purity samples of diamonds synthesized with HPHT and CVD technologies were used. The crystals of silicon carbide were grown by sublimation and industrial technology. Along with samples with a natural isotopic composition, monoisotopic crystals of diamond (99.96% 12C and 99.96% 13C) and silicon carbide (99.993% of 28Si) were studied. On the basis of the data obtained, the diamagnetic susceptibility was determined and the concentration of paramagnetic centers and the content of the ferromagnetic component were evaluated. The results are discussed.

Kinetic Carbon Isotope Effects in the Decarbonylation of Lactic Acid of Natural Isotopic Composition and of [1-14C] Lactic Acid

1994 ◽  
Vol 30 (4) ◽  
pp. 333-347 ◽  
Author(s):  
M. Zieliński ◽  
A. Zielińska ◽  
H. Papiernik-Zielińska ◽  
G. Czarnota ◽  
G. Kasprzyk ◽  
...  
Keyword(s):  
Lactic Acid ◽  
Isotopic Composition ◽  
Carbon Isotope ◽  
Isotope Effects ◽  
Natural Isotopic Composition

scholarly journals Paramagnetische Elektronenresonanz thermisch und durch Strahlung erzeugter Zentren in Bornitrid

1966 ◽  
Vol 21 (11) ◽  
pp. 1970-1975 ◽  
Author(s):  
G. Römelt
Keyword(s):  
Isotopic Composition ◽  
Line Width ◽  
Line Shape ◽  
X Rays ◽  
Natural Isotopic Composition ◽  
Epr Spectrum ◽  
Γ Radiation ◽  
Impurity Atoms ◽  
Gaussian Line Shape ◽  
Gaussian Line

By X-rays, ultraviolet, and γ-radiation or by heating to more than 1850 °C in powdered or sintered boronnitride centres are produced, which give an EPR-spectrum with 10 lines a=7.8 ± 0.1 Gauss apart with g=2.0027 ± 0.0003 for BN of natural isotopic composition (81.17% 11B; 18.83% 10B), and a single line for 10BN enriched to 91% 10B. The spectra are analysed as built up from 4 systems of spectra, caused by surroundings of 3 boron atoms, 3, 2, 1, or 0 of which are 11B, each occuring with the proper probability. The intensity of the different systems was calculated by assuming GAussian line shape and equal | ψ (0) |2 and line width for 11B and 10B. It is possible, that the EPR is caused by impurity atoms on the places of N or in the centre of B3N3-rings. Other spectra caused in BN by X-rays or by neutrons in a pile are discussed elsewhere 3, 8.

Carbon-13 and oxygen-18 isotope effects in the decarboxylation of nicotinic acid of natural isotopic composition

1998 ◽  
Vol 230 (1-2) ◽  
pp. 71-75
Author(s):  
M. Zieliński ◽  
A. Zielińska ◽  
H. Papiernik-Zielińska ◽  
J. A. McKenzie ◽  
S. Bernasconi ◽  
...  
Keyword(s):  
Isotopic Composition ◽  
Nicotinic Acid ◽  
Isotope Effects ◽  
Natural Isotopic Composition
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