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31.
The study of contamination effect during cryogenic grinding of pure cellulose was carried out. The optimisation of important parameters of the grinding process (pre-cooling time, grinding time, cooling time and number of cycles) was performed and the different sources of a possible contamination of samples (earlier processed sample, metal parts of grinding tool) were evaluated. The results of ICP-oa-TOF MS analysis after microwave digestion of cellulose samples were used in this study. Significant contamination of cellulose samples by Fe at the level 130 microg kg(-1) caused by wearing of steel stoppers and an impact bar was detected. Cross-contamination by Fe, Cr, Mn and Cu at the level 400, 200, 200 and 2100 microg kg(-1), respectively was caused by previous grinding of electro-waste sample. This cross-contamination was possible to be avoided by changing of a polycarbonate part of a grinding vessel. 相似文献
32.
Villablanca A Karhanek M Caramuta S Yu H Jejelowo O Webb CD Pourmand N 《Electrophoresis》2008,29(19):4109-4114
STR analysis is commonly used in forensic and genetic studies. STRs are currently discriminated based on size, primarily by gel- and column-based approaches. Hybridization-based approaches have the potential to allow high-throughput analysis of STRs; however, development of such approaches has been limited by the difficulty in discriminating between STRs of similar length. We have recently described several innovations to enable STR analysis using an array-based hybridization approach for high- throughput STR analysis. Here we extend that approach by incorporating the array into microspheres and adding a discriminatory branch migration displacement step. This microsphere-based platform uses Luminex xMAP technology and improves the sensitivity, selectivity, and speed of the assay. We demonstrate the feasibility, speed, and reliability of the assay for STR detection by correctly analyzing two STR loci in 20 forensic DNA samples of known STR type. The multiplex, bead-based approach provides a high-throughput and more portable STR analysis. 相似文献
33.
34.
Daniel Hork Miloslav Krytfek Jií Spv
ek 《Journal of polymer science. Part A, Polymer chemistry》2000,38(3):653-663
Nonporous hydrogel microspheres 0.1–1.3 μm in diameter were prepared by the dispersion copolymerization of 1‐vinyl‐2‐pyrrolidone and ethylene dimethacrylate as a crosslinking agent. The crosslinking was evidenced by solid state 13C NMR and elemental analysis. The effect of various parameters including selection of solvent (cyclohexane, butyl acetate), initiator (4,4′‐azobis(4‐cyanopentanoic acid), 2,2′‐azobisisobutyronitrile, dibenzoyl peroxide) and stabilizer on the properties of resulting microspheres has been studied. Dynamic light scattering and photographic examination were used for determination of the diameter and polydispersity of microspheres. Increasing concentration of steric stabilizer in the initial polymerization mixture decreased the particle size. The particle size depended on the molecular weight of polystyrene‐block‐hydrogenated polyisoprene stabilizer, but not on the number of PS and polybutadiene blocks in the styrene–butadiene block copolymer stabilizers. Dibenzoyl peroxide used as an initiator resulted in agglomeration of particles. © 2000 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 38: 653–663, 2000 相似文献
35.
Supersymmetric quantum mechanics is constructed in a new non-Hermitian representation. Firstly, the map between the partner
operators H
(±) is chosen antilinear. Secondly, both these components of a super-Hamiltonian $
\mathcal{H}
$
\mathcal{H}
are defined along certain topologically non-trivial complex curves r
(±)(x) which spread over several Riemann sheets of the wave function. The non-uniqueness of our choice of the map $
\mathcal{T}
$
\mathcal{T}
between ‘tobogganic’ partner curves r
(+)(x) and r
(−)(x) is emphasized. 相似文献
36.
Two membrane bioreactors (MBRs; volume = 300 L) equipped with different types of immersed membrane modules were operated simultaneously
under the same laboratory conditions as a low-loaded activated sludge process without any membrane regeneration and excess
sludge uptake (sludge retention time SRT up to 170 d; activated sludge concentration MLSS up to 11 g L−1). The aim was to verify the quality of treated water and to study the properties of "very old" activated sludge. Another
aim was to compare different selected membrane types and choose the best one for further pilot-scale testing.
Presented at the 35th International Conference of the Slovak Society of Chemical Engineering, Tatranské Matliare, 26–30 May
2008. 相似文献
37.
The creation of anoxic granulated biomass has been monitored in a laboratory USB (Upflow Sludge Blanket) reactor with the
volume of 3.6 L. The objective of this research was to verify the possibilities of post-denitrification of residual NO3-N concentrations in treated wastewater (denitrification of 10-20 mg L−1 NO3-N) and to determine the maximum hydraulic and mass loading of the granulated biomass reactor. G-phase from biodiesel production
and methanol were both tested as external organic denitrification substrates. The ratio of the organic substrate COD to NO3-N was 6. Only methanol was proven as a suitable organic substrate for this kind of reactor. However, the biomass adaptation
to the substrate took over a week. The cultivation of anoxic granulated biomass was reached at hydraulic loading of over 0.35
m h−1. The size of granules was smaller when compared with results found and described in literary reports (granules up to 1 mm);
however, settling properties were excellent and denitrification was deemed suitable for the USB reactor. Sludge volume indexes
of granules ranged from 35-50 mL g−1 and settling rates reached 11 m h−1. Maximum hydraulic and mass loadings in the USB reactor were 0.95 m3 m−2 h−1 and 6.6 kg m−3 d−1. At higher loading levels, a wash-out of the biomass occurred.
Presented at the 35th International Conference of the Slovak Society of Chemical Engineering, Tatranské Matliare, 26–30 May
2008. 相似文献
38.
Ladislav?KristoufekEmail author Miloslav?Vosvrda 《The European Physical Journal B - Condensed Matter and Complex Systems》2014,87(7):162
We utilize long-term memory, fractal dimension and approximate entropy as input variablesfor the Efficiency Index [L. Kristoufek, M. Vosvrda, Physica A 392, 184(2013)]. This way, we are able to comment on stock market efficiency after controlling fordifferent types of inefficiencies. Applying the methodology on 38 stock market indicesacross the world, we find that the most efficient markets are situated in the Eurozone(the Netherlands, France and Germany) and the least efficient ones in the Latin America(Venezuela and Chile). 相似文献
39.
Miloslav Znojil 《International Journal of Theoretical Physics》2014,53(8):2549-2557
The elementary quadratic plus inverse sextic interaction V (x) = x 2 + g 2/x 6 containing a strongly singular repulsive core in the origin is made regular by a complex shift of coordinate x = s ?iε. The shift ε > 0 is fixed while the value of s is kept real and potentially observable, s ∈ (?∞, ∞). The low-lying energies of bound states are found in closed form for the large couplings g ? 1. Within the asymptotically vanishing ??(g ?1/4) error bars these energies are real so that the time-evolution of the system may be expected unitary in an ad hoc physical Hilbert space. 相似文献
40.