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1.
Jozef Rychlý Lyda Matisov-Rychl Milan Lazr Ivica Janigov Matija Strli
Drago Ko
ar Jozef Hanus Jarmila Minrikov Svetozr Katu
k 《Comptes Rendus Chimie》2006,9(11-12):1425
Whatman cellulose impregnated with calcium and magnesium carbonates was oxidized and chemiluminescence accompanying this oxidation has been measured. It was shown that magnesium ions in deacidified cellulose pulp promote the light emission significantly. On the other hand, acid papers give the more pronounced light signals at temperatures close to ambient. The relation between chemiluminescence runs and paper degradation has been implicated, with an attempt to extrapolate half-lives of paper samples to conditions close to ambient. To cite this article: J. Rychlý et al., C. R. Chimie 9 (2006). 相似文献
2.
Search on ruggedness of fast gas chromatography-mass spectrometry in pesticide residues analysis 总被引:1,自引:0,他引:1
Kirchner M Matisová E Otrekal R Hercegová A de Zeeuwb J 《Journal of chromatography. A》2005,1084(1-2):63-70
In this study, suitability of fast gas chromatography-mass spectrometry (GC-MS) on a narrow-bore column with a programmed temperature vaporizer for the analysis of pesticide residues in non-fatty food was evaluated. The main objectives were ruggedness and stability of chromatographic system with regards to co-extractives injected. The chromatographic matrix induced response enhancement was found to be strongly dependent on the concentration of residues and is reaching up to 700% compared to the pesticides solutions in a neat solvent. However, the responses of pesticides in matrix-matched standards at different concentration levels do not significantly change during 130 injections. Response enhancement/or decrease is influenced by the sample preparation technique. External calibration with matrix-matched calibration standards should, therefore, provide results with good precision also at the concentration level of 0.005 mg kg(-1). Special attention is given to the performance of the chromatographic column and retention gap with regards to peak widths, peak tailing and different sample preparation methods. During approximately 460 matrix sample injections, the performance of the analytical column was acceptable. GC-MS set-up with 0.15 mm i.d. column can be successfully utilized for the pesticide residues analysis. 相似文献
3.
Summary Reproducibility of the Kovats retention indices of alkylbenzenes was studied on conventional “PONA” fused-silica capillary
columns coated with crosslinked dimethyl silicone phase, with a film thickness of 0.5 μm. The data were compared with those
obtained on conventional OV-101 columns. The tested PONA columns showed reproducible chromatographic properties, capacity
ratios and high efficiencies. Having a standard deviation of s=0.03 i.u. of the retention indices on a single column, the
column-to-columns differences were found to be up to 0.3 i.u. Higher indices were determined for crosslinked columns, the
difference being in most cases about one i.u. 相似文献
4.
Possibilities and practical aspects of implementation of splitless injection of larger volumes for fast GC purposes utilizing narrow-bore column, hydrogen as carrier gas, fast temperature programming under programmed flow conditions and commercial instrumentation were searched. As a model sample semivolatile compounds of a broad range of volatility and polarity (7 n-alkanes and 19 pesticides) were chosen. Peak shapes, peak broadening and peak areas and its repeatability were evaluated under various experimental set-ups (liner/injection technique combinations). Various factors, such as liner design, injection technique, retention gap length, compound volatility and polarity, the solvent used, initial oven temperature influenced compound focusation and/or maximal injection volume. Combination of analytical column (CP-Sil 13 CB 25 m long, 0.15 mm i.d., film thickness 0.4 microm) with normal-bore retention gap (1 m long, 0.32 mm i.d.) allowed maximal injection volume 8 microl for 4 mm i.d. liner used without any peak distortion when solvent recondensation in the retention gap was employed. 相似文献
5.
L. Matisová-Rychlá J. Rychlý P. Ambrovič M. Vavreková I. Paška 《European Polymer Journal》1980,16(7):631-635
From measurements of weight losses of samples of isotactic polypropylene (IPP) with triphenylphosphonium cyclopentadienylide (TPCP) under various conditions and from the measurements of time courses of chemiluminescence, kinetic parameters of the process were determined. At concentrations of TPCP >1 wt%, the rate of loss of weight changes with the additive concentration. Compensation of the values of activation energy and pre-exponential term, determined from thermo-oxidation of IPP alone and IPP with TPCP, indicates that interaction of TPCP with oxidized polymer is complex. 相似文献
6.
Lennard?P?NilesEmail author Kristen?J?Armstrong Lyda?M?Rincón Castro Chung?V?Dao Rohita?Sharma Catherine?R?McMillan Laurie?C?Doering David?L?Kirkham 《BMC neuroscience》2004,5(1):41
Background
In order to optimize the potential benefits of neural stem cell (NSC) transplantation for the treatment of neurodegenerative disorders, it is necessary to understand their biological characteristics. Although neurotrophin transduction strategies are promising, alternative approaches such as the modulation of intrinsic neurotrophin expression by NSCs, could also be beneficial. Therefore, utilizing the C17.2 neural stem cell line, we have examined the expression of selected neurotrophic factors under different in vitro conditions. In view of recent evidence suggesting a role for the pineal hormone melatonin in vertebrate development, it was also of interest to determine whether its G protein-coupled MT1 and MT2 receptors are expressed in NSCs. 相似文献7.
A solution is obtained for the system of Maxwell-Schrödinger equations describing the propagation of a laser pulse through a three-level Λ medium in which the initial atomic populations are in a specially prepared coherent superposition of low-energy states. This solution describes a new type of transparency which is characterized by the presence of conversion of the frequency of the incident pulse and can be used, specifically, to produce “optical keys” and frequency converters for laser radiation. 相似文献
8.
B. G. Matisov I. A. Grigorenko I. E. Mazets 《Journal of Experimental and Theoretical Physics》1997,85(3):469-473
We derive equations that describe the dynamics of three-level atoms with a cascade system of levels interacting with two resonant
coherent fields in conditions where cooperative relaxation dominates over incoherent spontaneous emission. We calculate the
temporal dynamics of the values of the atomic populations. The possibility of coherent population trapping in the presence
of the cooperative decay is established. Finally, we calculate the averaged population of the intermediate level as a function
of detuning for different values of the coupling constant.
Zh. éksp. Teor. Fiz. 112, 869–876 (September 1997) 相似文献
9.
10.
Optically confined (j=1, j=2)-Bose gas is studied. The spin Hamiltonian and the ground state of a set of particles with spins j=1 and j=2 are obtained. Nonlinear magnetic phenomena in the set of particles with j=1 are considered. 相似文献