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171.
Inga Zinicovscaia Liliana Cepoi Ludmila Rudi Tatiana Chiriac Dmitrii Grozdov Sergey Pavlov Svetlana Djur 《中国稀土学报(英文版)》2021,39(9):1133-1143
The growth of Arthrospira platensis and physiological changes in biomass under the effects of six rare earth elements Dy, Sm, Tb, La, Nd and Yb were evaluated. Elements were tested by three concentrations of 10, 20 and 30 mg/L. According to neutron activation analysis data A. platensis's accumulation capacity toward studied elements changes in the following order of La > Dy > Nd > Sm > Yb > Tb. The results show that Dy and La ions stimulate biomass growth and Yb ions inhibit it, while Sm, Tb and Nd ions do not affect biomass accumulation. The contents of proteins and chlorophyll a are not affected by the presence of rare earth elements in the cultivation medium. Studied elements affect to different extents carbohydrates, phycobilins, β-carotene, lipids and MDA contents in spirulina biomass. Changes in the antioxidant activity under applied metal loads reveal a moderate stress in exposed A. platensis. Cyanobacterium A. platensis can be successfully used for bioremediation of natural water contaminated with REEs as well as REEs recovery from low polluted industrial effluents. 相似文献
172.
Muhammad G Dastgir Frederico C Ferreira Ludmila G Peeva Andrew G Livingston 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》2004,79(4):381-390
This study describes the successful recovery of 2,4‐dichlorophenol (DCP) from wastewater using the Membrane Aromatic Recovery System (MARS). In the MARS process a non‐porous membrane separates a wastewater stream and a stripping solution. DCP is extracted from the wastewater and concentrated in its ionic form in the stripping solution, with pH ? pKa DCP. The MARS extraction stage was operated in batch mode with the stripping solution placed inside, and the wastewater stream outside, the membrane tubes. Advantages of this configuration are avoidance of membrane blockage, reduction of stripping solution volume and operational flexibility. The stability and mass‐transfer characteristics of two different membrane materials, poly(dimethylsiloxane) (PDMS) and ethylene–propylene diene terpolymer (EPDM), were tested in DCP solutions with different acidities in order to simulate real industrial waste streams. EPDM exhibits one order of magnitude lower mass‐transfer rates than PDMS (1.4 × 10?7 m s?1 vs 20 × 10?7 m s?1 at 30 °C and 2.4 × 10?7 m s?1 vs 39 × 10?7 m s?1 at 60 °C), however its higher resistance to acid attack provides higher membrane lifetimes. This can be crucial for MARS processes treating real acidic industrial wastewater. A 97% recovery of DCP with a water content of 15 wt% was obtained upon neutralisation of the stripping solution. Copyright © 2004 Society of Chemical Industry 相似文献
173.
Anastasiya P. Mosalkova Sergei V. Voitekhovich Alexander S. Lyakhov Ludmila S. Ivashkevich Mikhail M. Degtyarik Pavel N. Gaponik Oleg A. Ivashkevich 《Inorganic chemistry communications》2009,12(10):998-1000
For the first time, tetrazolate complexes have been prepared by direct synthesis. Two novel homo- and heterometallic mixed-ligand complexes, Cu(en)(tz)2 and Cu(en)2Zn(tz)4, have been synthesized using tetrazole (Htz), ethylenediamine (en), metallic copper and zinc oxide as starting materials. Both tetrazolates were characterized by single-crystal X-ray diffraction, IR spectroscopy and thermal analysis. The complexes present 1D coordination polymers, with tetrazolate anions acting as both monodentate and bridging ligands. 相似文献
174.
Ivan Kelnar Jakub Rotrekl Jiří Kotek Ludmila Kaprálková 《Polymer International》2008,57(11):1281-1286
BACKGROUND: In nanocomposites with multiphase matrices, the addition of layered silicate not only has a reinforcing effect, but also changes significantly the morphology, namely the size and the structure of the dispersed phase. In this paper, we focus on systems with polyamide 6 (PA6)/polystyrene (PS) matrices. The effect of clay was studied over the whole composition range together with the simultaneous variation of basic parameters influencing the structure and mechanical behaviour, i.e. the clay treatment type and mixing protocol. RESULTS: At all compositions, remarkable refinements of both particulate and co‐continuous structures by clay were found. This effect and a significant shift of the glass transition temperature of blend components were more pronounced for clay with less polar treatment as a result of distinct localization of clay in the interfacial area (due to its lower affinity for PA6 phase). An increase in modulus was found at all compositions, whereas strength and toughness were enhanced at low PS contents only, as a consequence of small particle size and enhanced interfacial bonding. CONCLUSIONS: The results presented indicate that nanosilicates can effectively influence the structure and properties of PA6/PS blends. Copyright © 2008 Society of Chemical Industry 相似文献
175.
Bogdan Belgorodsky Eyal Drug Ludmila Fadeev Netta Hendler Elad Mentovich Michael Gozin 《Small (Weinheim an der Bergstrasse, Germany)》2010,6(2):262-269
In recent years, the exposure of biological systems to various nanomaterials has become an issue of great public concern. Although living organisms have arrays of biological defense mechanisms against exposure to exogenous compounds, the biochemical mechanisms allowing various nanomaterials to enter the body are not well understood. A unique example of a typical mucosal glycoprotein capable of binding and solubilizing nanomaterials in physiological solution is provided, suggesting a possible route for entry into biological systems. 相似文献
176.
177.
We propose asynchronous parallel algorithms for numerically solving systems of hyperbolic partial differential equations. The algorithms are based on the solutions along the characteristic directions. We show that the characteristic directions can be computed in parallel without the need for sharing information or synchronizing on a common time step. This permits the development of efficient asynchronous parallel algorithms. Our solutions cover the cases when the characteristic lines are intersected to form shock waves. We discuss the time performance of our algorithms as well as their implementation on a parallel computer.Supported by the R&D administration of the Ministry of Defense and the Ministry of Immigration Absorption, Israel. 相似文献
178.
We investigate the property of self-stabilization in bounded Petri nets. We give characterizations for both self-stabilizing bounded ordinary Petri nets (i.e., Petri nets without multiple arcs) and self-stabilizing bounded general Petri nets (i.e., Petri nets with multiple arcs). These characterizations allow us to determine the complexity of deciding self-stabilization for each of these classes. In particular, we show the self-stabilization problem to be PTIME-complete for bounded ordinary Petri nets and PSPACE-complete for bounded general Petri nets.Louis Rosier passed away on May 6, 1991, while this paper was under review 相似文献
179.
180.