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991.
Biofiltration is one of the techniques used to reduce odorants in the air. It is based on the aerobic degradation of pollutants by microorganisms located in the filter bed. The research presents the possibility of using the electronic nose prototype for monitoring and efficiency assessment of air biofiltration. The study was conducted using model gas mixtures containing representatives of three groups of chemical compounds: n-hexane (alkanes), acetone (ketones) and toluene (aromatic hydrocarbons). Based on the proposed linear models it has been shown that the determination of concentrations of these substances in the ternary mixture is possible at relatively low concentrations. It was also shown that the used filter medium (pine bark) had the highest removal efficiency of acetone. 相似文献
992.
Paweł Świt Jorge Verdú-Andrés Joanna Kozak Paweł Kościelniak Pilar Campíns-Falcó 《Analytical letters》2018,51(8):1194-1207
A new calibration methodology based on the combination of integrated calibration method (ICM) and the H-point standard addition method (HPSAM) is presented. It allows the diagnosis and correction of errors caused in an analytical system by different kinds of interference effects. Six calibration solutions consisting of mixtures of sample, diluent, and one standard are prepared in accordance with the ICM principle to integrate the external calibration method with the standard addition method and thereby to detect and eliminate proportional interferences. Absorbance increments chosen according to the HPSAM principle are proposed to correct the errors caused by additive interferences. A set of as many as six apparent estimations of analyte concentration in a single calibration procedure is calculated for validating accuracy. As a consequence, doing calibration by the ICM-HPSAM method, it is possible to obtain the final analytical results with considerably improved accuracy. The determination of calcium in several different water samples (containing amounts between 4.9 and 127?mg?L?1) with Arsenazo III has been chosen as an example because it is biased if the errors are not diagnosed and corrected. The results are characterized by small (not higher than 8%) relative error (RE), and good precision (RSD values smaller than 6%). 相似文献
993.
UV spectra and absorption coefficients of biologically active copolymers of maleic anhydride with carbohydrates, terpenes and 1,3-dioxane derivatives were measured. The quantitative relationships of absorbance vs concentrations of polymers were determined as well. The possibility of determining the copolymer contamination due to monomers and oligomeric compounds was shown. 相似文献
994.
The MNDO andab initio (Hartree—Fock method, split 6-31G* basis set, full optimization of geometry) calculations for theo- andm-dichlorobenzene molecules have been performed. The populations of the valent p-orbitals of the carbon and chlorine atoms have been analyzed. Estimations of the35Cl NQR frequencies and the asymmetry parameters of the electric field gradient at the35CI nuclei have been made. It was confirmed that these values are not determined by the contribution of the whole valent p-shell, but only by its less diffuse component.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 2180–2183, September, 1996. 相似文献
995.
The reduction of CrO3 with an excess of L-ascorbic acid and its interaction with DNA fragments (adenine, adenosine) and the ATP nucleotide was studied by the analysis of the isolated solid products. The precipitates were characterised by elemental analyses, FAB-mass spectral data, spectroscopic methods (u.v.–vis., i.r) and magnetic measurements. The CrIII complexes obtained from ternary systems appeared to be [CrIII–L-ascorbic acid] and
[CrIII–L-ascorbic acid–adenine (adenosine, ATP)] species. The structure of ternary complexes has been proposed assuming hydrogen bond formation between the [CrIII–ascorbic acid] complex and the DNA components. The effect of main cellular reductants: cysteine, glutathione and L-ascorbic acid on the composition and structure of isolated products has been discussed. 相似文献
996.
The anomalous coherence functions (ACF) of collective resonance fluorescence are calculated analytically forN two-level atoms, coherently driven by a strong laser field and distributed in a region much smaller than the resonant wavelength. It is shown that the anomalous coherence functions are nonzero for transient as well as steady-state resonance fluorescence. The values of ACF are dependent on the number of atoms and the initial atomic populations. For one-atom resonance fluorescence, the one-time ACF vanishes whereas the two-time ACF differ from zero irrespective of the number of atoms. Moreover, it is found that information about the higher-order resonance at 2Θ, where Θ is the Rabi frequency, is conveyed by the ACF's only in the transient régime of resonance fluorescence. For steady-state resonance fluorescence, the ACF's carry information similar to that carried by the correlation function that yields the fluorescent spectrum. We also discuss the possibility of measuring the ACF's using photon-counting techniques. 相似文献
997.
P. Myśliński P. Kamasa A. Gilewicz J. Staśkiewicz 《Journal of Thermal Analysis and Calorimetry》2007,88(3):737-740
The work is aimed to develop the diagnostic method for testing the state of surface coated with the wear-resistant films.
Thin wear-resistant ceramic films based on titanium such as TiN, TiCN, TiAlN are deposited on working surface of cutting tools
or machine elements in order to improve their tribological properties. The operation life depends mainly on the residual stresses
occurring in films and the kinetics of their relaxation as a function of temperature and time. The value of the stresses is
influenced by the technological conditions of film deposition and the physical and chemical properties of the substrate and
film.
The paper has demonstrated the usability of the modulated-temperature dilatometry (MT DIL) for recording the changes in mechanical
effects of the adhesive film on the substrate as a function of temperature and time. The substrates where in the shape of
cylindrical rod, 30 mm length and 3 mm diameter and of the ribbon 30 mm in length, 2 mm in wide and 120 μm thick. The thickness
of the coatings was from 2 to 3 μm. The films deposition were performed using the physical vapour deposition (PVD) technique. 相似文献
998.
The osmotic coefficients for CoSO4, NiSO4, CuSO4, MnSO4, and ZnSO4 have been found to be approximately the same up to very highest concentrations, while they are significantly higher for MgSO4. Negligible changes in the visible spectra of CoSO4 and NiSO4 induced by increasing concentration indicate little, if any, coordination of the sulfate anion, while the UV spectral effects indicate outer-sphere association. More distinct spectral effects are observed for CuSO4. However, the free sulfate anion concentration is found to be the same in equimolal solutions of CoSO4, NiSO4, and ZnSO4, and probably also in CuSO4, while it is higher in the solutions of MgSO4. The conclusion is drawn that the four isopiestic transition metal sulfates at any given molality are in corresponding coordination states. The general problem of correlation between thermodynamic properties of solutions and the coordination states of the dissolved salts is discussed. 相似文献
999.
The aim of the present work is to find relation between the state of ceramic coating of iron and the physical properties of
coated samples as a function of temperature. The iron samples coated by plasma assisted physical vapor deposition (PA PVD)
with layers of TiN were investigated with new technique – temperature modulated thermomagnetometry (TM TMAG) and thermal dilatometry
(TM DIL). From the irregular behavior of the thermal dilatation and magnetic susceptibility, the process of the coating degradation
can be resolved.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
1000.
Piotr Konieczka Thomas P. J. Linsinger Jacek Namieśnik 《Accreditation and quality assurance》2006,11(11):584-589
Thirty Polish laboratories participated in proficiency tests (PT) for determination of persistent organic pollutants – POPs (PCBs – polychlorinated biphenyls, PAHs – polyaromatic hydrocarbons and pesticides) in solid environmental matrices (sediments, soil). Participants used their in-house method. The aim of the exercises was to obtain information about the “state of the art” of POPs analysis in environmental samples. The CV (coefficient of variation) of analytical results submitted varied from 45 to 65%, with an outlier rate 2 to 7%. The averages of results for all analytes were in good agreement with reference values. Statistical treatment of results was made. Comparison of the each result with the certified values characterizing the material has been done. Additionally, z-scores were calculated taking into account the uncertainty of a certified value and the acceptable deviation from the certified value in the range of −20% to +10% (in accordance with recommendations in the newest directives of European Union (EU) [1]); For rejecting outliers Hampel test has been applied. 相似文献