Authors:L. Mosulishvili, M. Kolomi'tsev, V. Dundua, N. Shonia, and O. Danilova
Standards for instrumental neutron activation analysis (INAA) of biological materials are proposed. The standards are multielement
solid solutions in phenol-formaldehyde resole resin (PFR) moulded as pellets weighing 30 to 50 mg. The concentrations of trace
elements in the standards are selected so that, firstly, they are commensurable with their concentrations in the biological
materials and, secondly, that the analytical lines of each of the elements incorporated in PFR are resolved with the aid of
modern equipment. The principal standard contains 21 trace elements from among those of greatest interest for INAA of biological
materials. This standard is recommended for work on high-resolution equipment. At the same time, standards of simpler trace
element composition have been prepared and studied which can be used in work on simpler equipment or in solving particular
problems in determination of certain groups of chemical elements.
The standard (p0=0.1 MPa) molar enthalpy of formation of 1-cyanoacetylpiperidine, in the crystalline state, at T=298.15 K, has been derived from measurements of its standard massic energy of combustion, by static bomb combustion calorimetry,
as ΔfHm0=−217.1±1.4 kJ mol−1. The standard molar enthalpy of sublimation was measured, at T=298.15 K, by the microcalorimetric sublimation technique as ΔcrgHm0=103.5±1.9 kJ mol−1.
The standard (p0=0.1
MPa) molar enthalpy of formation, ΔfH0m, for crystalline N-phenylphthalimide
was derived from its standard molar enthalpy of combustion, in oxygen, at
the temperature 298.15 K, measured by static bomb-combustion calorimetry,
as –206.03.4 kJ mol–1. The
standard molar enthalpy of sublimation, ΔgcrH0m
, at T=298.15 K, was derived, from high
temperature Calvet microcalorimetry, as 121.31.0 kJ mol–1.
The derived standard molar enthalpy of formation, in the gaseous state,
is analysed in terms of enthalpic increments and interpreted in terms of molecular
Dy content has been determined by INAA in the Bulgarian standard rocks BV, GV, DM, MrA, OgG, OZnO and in the IAEA standard reference materials SL-1, SOIL-5, and SOIL-7. Results are compared with Dy values obtained by interpolation of the chondrite-normalized contents of other REE in these samples.
Four different approaches to PIXE data obtained in repeated measurements on thick standards have been evaluated in terms of precision and accuracy. Both were found to be the best when determinations relative to an external standard were normalized to a composition assumed to be 100% oxides.
Until the mid-19th century, Slovenia had two distinct territorial fields of language use that coexisted in the central and eastern Slovene linguistic, administrative-political, and geographical areas: (1) central Slovene (the so-called kranjščina) and (2) eastern Slovene (the language of Prekmurje and eastern Štajerska). Their half-century long convergence, permeation and entwinement resulted in a formation of the unified norm of standard Slovene in the middle of the 19th century (the so-called new Slovene or unified standard Slovene). In the past, this double development of the Slovene standard language was incorrectly explained – instead of applying a double notion based on historical development (central Slovene standard language and eastern Slovene standard language), an inaccurate opposite emerged: standard language vs. standard language delusions. The attempt of a black and white portrayal of the linguistic circumstances in the development of Slovenian was to enact the linguistic equation central vs. peripheral = norm vs. particularism. Through this attempt, standard Slovene was equal to the central, correct and distinguished language with its opposite, the incorrect regional language of the Slovenian language periphery.
In radiochemical neutron activation analysis, standards may be measured directly or subjected to the same radiochemical processing as the sample. Some considerations in regard to processing are examined, and the advantages and disadvantages of this approach discussed. It is concluded that processing of standards is often inadvisable and can lead to errors, particularly if used as a substitute for radiochemical yield determinations.
A suitable standard smaple was developed and tested on the basis of phosphorus for the quantitative autoradiography of elements
of interest in semiconductor technology. By the aid of silicon disks with a phosphorus concentration of 6·1017 atoms·cm−2 the error of the quantitative autoradiographic method is determined. The relative mean error of the density measurement is
at best ±4%; the relative mean error of the determination of phosphorus concentration by use of an error-free standard sample
is about ±15%. This method will be extended to other elements by use of this standard sample of phosphorus.
The present work reports the experimental determination of the standard (po = 0.1 MPa) molar enthalpies of formation in the condensed and gaseous phases, at T = 298.15 K, of 5- and 6-nitroindazole. These results were derived from the measurements of the standard molar energies of
combustion, using a static bomb calorimeter and from the standard molar enthalpies of sublimation derived by the application
of Clausius–Clapeyron to the temperature dependence of the vapour pressures measured by the Knudsen effusion technique. The
results are interpreted in terms of the energetic contributions of the nitro groups in the different positions of the aromatic