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21.
Vladimír Kompi? Zuzana Mur?inková Sergey Rjasanow Richards Grzibovskis Qinghua Qin 《Frontiers of Architecture and Civil Engineering in China》2010,4(3):396-401
Trefftz-finite element method (Trefftz-FEM), adaptive cross approximation BEM (ACA BEM) and continuous source function method
(CSFM) are used for the simulation of composites reinforced by short fibers (CRSF) with the aim of showing the possibilities
of reducing the problem of complicated and important interactions in such composite materials. 相似文献
22.
Zuzana Mácová Karel Bouzek Virender K. Sharma 《Journal of Applied Electrochemistry》2010,40(5):1019-1028
The influence of anolyte composition and temperature on the anode dissolution kinetics of pure iron and subsequent ferrate(VI) production was studied by means of potentiodynamic voltammetry and electrochemical impedance spectroscopy. The results obtained were verified by batch electrolyses. Pure NaOH, KOH, and mixtures thereof were used as an anolyte. The motivation for this study is to understand in more detail the electrolysis process at which ferrate(VI) is electrochemically produced in situ in the solid form which is more suitable for practical utilization. A significant impact of the anolyte composition on the system behavior was indicated. It is related to the solubility of the anode dissolution products in the anolyte. It was concluded that the fast reaction kinetics in the transpassive potential region is connected with a deterioration of the ferrate(VI) synthesis efficiency. This is explained by the kinetic enhancement corresponding to the intensification of oxygen evolution as a parasitic reaction. 相似文献
23.
Michal KORENKO ;Zuzana VASKOVA ;Frantisek SIMKO ;MICHAL SIMURDA ;Marta AMBROVA ;石忠宁 《中国有色金属学会会刊》2014,24(12):3944-3948
以热解碳化硼管作电导池,用固定电导池常数法研究由Na F-Al F3-Si O2构成的二元系和三元系熔盐的电导率;用扭摆法测定Na3Al F6-Si O2二元系的黏度。研究发现,所研究熔盐体系的电导率和黏度均与温度呈直线关系。Na3Al F6-Si O2二元系的电导率与Si O2含量关系曲线可分为0-10%和10%-40%(摩尔分数)两段,当SiO 2含量超过10%之后,电导率随着Si O2含量的增加而快速下降,而当Si O2含量小于10%时,电导率随着Si O2含量的增加而缓慢增加。在Si O2含量大于10%的冰晶石熔盐中添加少量的SiO 2,熔盐的黏度增加,但增加的趋势基本相同,这与熔盐中形成玻璃网状结构的离子团有关。当在冰晶石熔盐中继续增大Si O2含量到50%时,黏度发生急剧变化。 相似文献
24.
The anolyte composition and process temperature could improve the kinetics of iron anode dissolution and subsequent ferrate(VI)
production significantly. This also holds for the anode composition. Following pure iron and silicon-rich steel (SRS), white
cast iron (WCI) was the last representative of anode material tested that is typically used to produce ferrate(VI). Using
anolytes 14 M NaOH, 14 M KOH, and mixtures thereof, the systems were studied by potentiodynamic methods, electrochemical impedance
spectroscopy, and batch electrolysis experiments. Additionally, metallographic analysis of the material was performed. The
dissolution kinetics increases with increasing temperature and also, at 60 °C, with increasing K+ content in the anolyte, but less progressively than in the case of SRS. Similar to SRS, WCI also easily dissolves into ferrate(VI)
even at 20 °C in pure NaOH, thus indicating the inferior protective properties of oxo-hydroxide surface layers. In general,
a maximum current efficiency of approx. 60 % was obtained at 60 °C in pure KOH solution. The authors conclude that, at 60 °C,
the high efficiency of the synthesis is caused by the low protective properties of the oxo-hydroxide surface layer caused
by the preferential dissolution of cementite and at the same time by the precipitation of the potassium salt of the product
in the electrolyte immediately after its formation. This minimizes the effect of its decomposition. 相似文献
25.
The external egg morphology of two stored-product pests, Stegobium paniceum and Lasioderma serricorne, is presented herein based on optical and scanning electron microscope micrographs. The diagnostic characteristics of the eggs of the pests, including the presence or absence of a micropyle, are described and discussed. Overall, several notable differences were observed between the eggs of these species in regard to their shape, size and surface structures. 相似文献
26.
Zuzana Dimitrovová Hélder C. Rodrigues 《Structural and Multidisciplinary Optimization》2010,42(3):325-340
The contribution of optimization has been essential to the more recent developments in design of new mechanical structures
and materials. The objective of this work is to apply the models of material and structural optimization to the design of
passive vibration isolators. A computational tool to identify the optimal viscoelastic characteristics of a nonlinear one-dimensional
isolator was developed. The cost functional involves the minimization of a weighted average of the maximum transient and steady
state response amplitudes for a set of predefined dynamic loads. The optimal isolator behaviour is obtained by a simulated
annealing method. The solutions obtained are analyzed and discussed concerning their dependence on the applied forces and
objective function selection. The results obtained can facilitate the design of elastomeric materials with improved behaviour
in terms of dynamic stiffness for passive vibration control. 相似文献
27.
Anna Golunova Nadiia Velychkivska Zuzana Mikovsk Vclav Chochola Josef Jaro Ale Hampl Ognen Pop-Georgievski Vladimír Proks 《International journal of molecular sciences》2021,22(11)
In the fast-developing field of tissue engineering there is a constant demand for new materials as scaffolds for cell seeding, which can better mimic a natural extracellular matrix as well as control cell behavior. Among other materials, polysaccharides are widely used for this purpose. One of the main candidates for scaffold fabrication is alginate. However, it lacks sites for cell adhesion. That is why one of the steps toward the development of suitable scaffolds for cells is the introduction of the biofunctionality to the alginate structure. In this work we focused on bone-sialoprotein derived peptide (TYRAY) conjugation to the molecule of alginate. Here the comparison study on four different approaches of peptide conjugation was performed including traditional and novel modification methods, based on 1-Ethyl-3-(3-dimethylaminopropyl)carbodiimide/N-hydroxy succinimide (EDC/NHS), 4-(4,6-dimethoxy-1,3,5-triazine-2-yl)-4-methylmorpholinium chloride (DMTMM), thiol-Michael addition and Cu-catalyzed azide–alkyne cycloaddition reactions. It was shown that the combination of the alginate amidation with the use of and subsequent Cu-catalyzed azide–alkyne cycloaddition led to efficient peptide conjugation, which was proven with both NMR and XPS methods. Moreover, the cell culture experiment proved the positive effect of peptide presence on the adhesion of human embryonic stem cells. 相似文献
28.
Cesar D. Fermin Ellis Diaz Aura Maldonado Dale Martin Zuzana Hruska 《Microscopy research and technique》1990,16(1):85-86
Kodak black and while film emulsions 4489, 4162, 2415, TMAX-100, TMAX-400, MPD-4 and RPC-651 can be developed in less than 10 minutes on a film processor, quickly printed on resin coated paper and dried with auto-processor and dryer. Adjustments to the ASA (ISO) to compensate for increased contrast with auto-processing are described. 相似文献
29.
Zuzana Jehliková Jana Hajlová Jan Poustka Frantiek Pudil Jii Davidek 《Zeitschrift für Lebensmitteluntersuchung und -Forschung A》1990,190(5):436-440
Summary A reproducible and sensitive gas Chromatographic method has been developed for the trace analysis of fluazifop-butyl, haloxyfop-ethoxyethyl and quizalofop-ethyl as well as their main metabolites (corresponding acids analysed after conversion to methyl esters) in some fruits and vegetables treated with herbicidal sprays. Comparable detection limits (0.01 mg/kg) were achieved when mass fragmentography and/or the electron capture detector were employed. However, in the latter case, bromination of fluazifop esters had to be carried out prior to GC analysis. By means of the nitrogen-phosphorus detector, determination of residues at a level of 0.05 mg/kg was possible. The residue values found in strawberries, cabbages, cauliflowers and carrots were used to discuss the degree of metabolic hydrolysis of parent esters, i.e. active ingredients of herbicides.
Bestimmung von Aryloxyphenoxypropionsäure-Derivaten in mit Herbicidsprays behandelten Produkten
Zusammenfassung Es wurde eine gaschromatographische Methode zur quantitativen und selektiven Bestimmung von Fluazifop-butyl, Haloxyfop-ethoxyethyl und Quizalofop-ethyl sowie von ihren Hauptmetaboliten (den entsprechenden Säuren, die zu Methylestern umgesetzt werden müssen) in mit Herbiciden behandelten Obst- und Gemüseproben entwickelt. Eine Nachweisgrenze von 0,01 mg/kg wurde durch Elektroneneinfanggaschromatographie oder durch Massenfragmentographie erzielt. Um die gleiche Empfindlichkeit des EC-Detektors bei Fluazifop zu erreichen, wurden die beiden Ester mit Brom umgesetzt. Mit Hilfe des NP-Detektors konnte eine Nachweisgrenze von 0,05 mg/kg erreicht werden. Die festgestellten Rückstandsgehalte in Erdbeeren, Kohl, Blumenkohl und Möhren wurden gleichzeitig zur Beurteilung der metabolischen Hydrolyse der diskutierten Ester (der Wirkstoffe der Herbicide) herangezogen.相似文献
30.
Kronek J Kroneková Z Lustoň J Paulovičová E Paulovičová L Mendrek B 《Journal of materials science. Materials in medicine》2011,22(7):1725-1734
Poly(2-oxazolines) with varying alkyl chain lengths (e.g., methyl, ethyl, aryl) and molar masses have been tested for cell
cytotoxicity in vitro. A standard 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay was used for the
estimation of cell viability. Two monomers, 2-methyl-2-oxazoline and 2-ethyl-2-oxazoline, were found to provide polymers with
non-cytotoxic properties. The dependence of cell viability on molar mass confirmed the expected trend; the viability increased
with the higher molar mass of poly(2-ethyl-2-oxazoline) (PETOX), up to 15,000 g/mol. The results obtained for the polymers
with aliphatic side chains were compared with the analogues that possessed an aromatic moiety. All results confirmed low cytotoxicity
of the polymers prepared by cationic polymerization of 2-alkyl- and 2-aryl-2-oxazolines, which supports their utilization
in biomedical applications. Fluorescence microscopy and steady-state fluorescence were used to observe pyrene-labeled polymer
interactions with living cells. Polymer accumulated within the cells was found to be dependent on polymer concentration in
media. The immunoefficiency of aromatic and aliphatic oxazoline polymers and copolymers was also studied. Phagocytic and metabolic
activities of macrophages were used to assess the immunosuppressive effects of the selected copolymers for possible applications
in drug delivery and immunobiology. Overall, the tested polymers demonstrated no significant influences on the cellular immunological
parameters. 相似文献