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1.
Summary Micromolar analyses of the nitrogen species NH3, NO
2
–
, and NO
3
–
in soil and other samples are usually accomplished by extracting several samples and testing each for a different species. This procedure is not viable when the quantity of the initial sample is limited. An improved method of separating and analysing for ammonia NH3(aq), nitrite NO
2
–
(aq), and nitrate NO
3
–
(aq) from a single small sample with concentrations of 0–50 mol/l is reported. No interferences or carryovers among the three nitrogen containing species were found. Uncertainties were ±2–5 mol/l and accuracies with respect to standards were ±3 mol/l. 相似文献
2.
There are only a few methods of dosimetry which can estimate the contribution of different particles to onboard spacecraft
and/or aircraft exposure. This contribution describes an attempt to estimate the contribution of different components to the
exposure level using MDU-Liulin energy deposition spectrometer and thermoluminescent detectors (TLD’s), in combination with
a spectrometer of linear energy transfer (LET) based on track etch detectors. This equipment was exposed onboard: the International
Space Station for a long period and two shorter shuttle missions and a commercial subsonic aircraft for several long-term
monitoring periods from 2001 to 2006. The data obtained are analyzed from several points of view and the obtained results
are presented, analyzed, and discussed.
The text was submitted by the authors in English. 相似文献
3.
We prove that any -additive family of sets in an absolutely Souslin metric space has a -discrete refinement provided every partial selector set for is -discrete. As a corollary we obtain that every mapping of a metric space onto an absolutely Souslin metric space, which maps -sets to -sets and has complete fibers, admits a section of the first class. The invariance of Borel and Souslin sets under mappings with complete fibers, which preserves -sets, is shown as an application of the previous result.
4.
K. R. Spurny J. Schörmann R. Kaufmann 《Fresenius' Journal of Analytical Chemistry》1981,308(3):274-279
Summary Analysis of asbestos and glass fibers obtained by either environmental sampling or after longer periods of deposition in human and animal tissue revealed that the latter undergo changes of their chemical composition. Electron microscopy and LAMMA were used in these investigations. The extent of fiber dissolution could be assessed. Some fibers remained chemically unchanged. In certain fibers only some elements were partially leached out whereas in other fibers the majority of metallic elements were eluted.
Identifizierung und Mikroanalyse von mineralischen Fasern mit Hilfe von LAMMA相似文献
5.
J.?Luke?Email author J.?Maly I.?Netuka M.?Smr?ka J.?Spurny 《Israel Journal of Mathematics》2003,134(1):255-287
It is known (G. Choquet, G. Mokobodzki) that a Baire-one affine function on a compact convex set satisfies the barycentric
formula and can be expressed as a pointwise limit of a sequence of continuous affine functions. Moreover, the space of Baire-one
affine functions is uniformly closed. The aim of this paper is to discuss to what extent analogous properties are true in
the context of general function spaces.
In particular, we investigate the function spaceH(U), consisting of the functions continuous on the closure of a bounded open setU⊂ℝ
m
and harmonic onU, which has been extensively studied in potential theory. We demonstrate that the barycentric formula does not hold for the
spaceB
1
b
(H(U)) of bounded functions which are pointwise limits of functions from the spaceH(U) and thatB
1
b
(H(U)) is not uniformly closed. On the other hand, every Baire-oneH(U)-affine function (in particular a solution of the generalized Dirichlet problem for continuous boundary data) is a pointwise
limit of a bounded sequence of functions belonging toH(U).
It turns out that such a situation always occurs for simplicial spaces whereas it is not the case for general function spaces.
The paper provides several characterizations of those Baire-one functions which can be approximated pointwise by bounded sequences
of elements of a given function space.
Research supported in part by grants GA ČR No. 201/00/0767 from the Grant Agency of the Czech Republic, GA UK 165/99 from
the Grant Agency of Charles University, and in part by grant number MSM 113200007 from the Czech Ministry of Education. 相似文献
6.
Journal of Applied Mechanics and Technical Physics - 相似文献
7.
Summary The time course of the phase transition in the system Th4+/dodecylsulfate/HClO4 has been measured by kinetic photometry. In micellar solutions initially formed solid particles are slowly dissolved by solubilisation. 相似文献
8.
This contribution describes the results of fragmentation of Ne ions with primary energy 400 MeV/u behind different shielding measured with plastic nuclear track detectors in the frame of experiments at HIMAC. The detectors were placed behind 6 different materials (PMMA, Teflon, graphite, Al, Fe, Cu) of various thicknesses, from the entrance up to the depths before the Bragg peak. Spectra of linear energy transfer were obtained for all materials and various thicknesses of the shielding used. Attenuation of primary Ne ions in various materials and the contribution of secondary particles and fragments to the total measured dose are presented. 相似文献
9.
Kvetoslav R. Spurny Werner Stöber 《International journal of environmental analytical chemistry》2013,93(4):265-281
Abstract Nuclepore filters were used for sampling and evaluation of fibrous particles in ambient air, in liquids and in biological materials. The fiber counting and fiber size measurements were done by means of SEM-methods. The number of fibers and the distributions of fiber lengths and diameters were plotted. The specific identifications of asbestos, glass and other mineral fibrous particles were made by electron microprobe analysis. Certain elements proved to be approximative identification factors for different fibrous minerals in ambient air, in liquids, on material surfaces, or in biological materials. For ambient air, asbestos, glass, and many other inorganic fibrous particles were found in the urban atmosphere as well as in the atmosphere of remote regions. Fibrous gypsum, fibrous ammonium sulfates, fibrous silicates, fibrous mica, and quartz were identified among these particles. Even in remote ambient air, relatively high concentrations of inorganic fibrous particles could be measured. 相似文献
10.
Three types of detectors were used onboard the MIR station during the 28th base expeditions to characterise the radiation field: a linear energy transfer (LET) spectrometer was used to establish the LET spectrum between 7 and 700 keV/micrometers corresponding mostly to secondary charged particles; a set of thermoluminescent detectors was used to characterise the low LET component of the onboard radiation field; and Si-diodes were installed to determine the contribution to the exposure due to fast neutrons. It was found out that the LET spectrum from secondary particles between 7 and 700 KeV/micrometers does not depend on the external radiator; the average quality factors for the region mentioned are about 6.0 with ICRP 26 quality factors and about 6.8 with ICRP 60 quality factors. Both differential and integral LET spectra are presented for some typical cases, not only for particle number but also for the dose characteristics like dose and dose equivalent. The spectra obtained also permitted us to calculate the total doses and dose equivalents due to secondary particles with the LET values between 7 and 700 keV/micrometers. It was found out that these quantities are higher for the case of detectors placed in the less shielded area, both for the LET spectrometer (high LET part) as well as for TLDs measuring the low LET component. Total dosimetric characteristics obtained as a sum of both components mentioned are a little lower than previously reported. 相似文献