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241.
Sergei V. Voitekhovich Tatiyana V. Serebryanskaya Pavel N. Gaponik Ludmila S. Ivashkevich Alexander S. Lyakhov Oleg A. Ivashkevich 《Inorganic chemistry communications》2010,13(8):949-951
Tetrazol-2-ylacetic acid (2-TzaH) was found to react with CuCl2, PdCl2, and K2PtCl4 in water giving Cu(2-Tza)2, PdCl2(2-TzaH)2·2H2O and PtCl2(2-TzaH)2, correspondingly. Obtained complexes, being the first reported examples of coordination compounds derived from 2-TzaH, have been characterized by IR spectroscopy, thermal and X-ray diffraction methods. 2-TzaH was found to act as a monodentate ligand coordinated to the metal ion via N4 atom of heteroring in palladium complex and as tridentate bridging ligand coordinated via N4 atom and two oxygen atoms in copper complex. Cu(2-Tza)2 presents 2D coordination polymer, whereas PdCl2(2-TzaH)2·2H2O is molecular complex. 相似文献
242.
Emmanuel Richaud Xavier Colin Carole Monchy‐Leroy Ludmila Audouin Jacques Verdu 《Polymer International》2011,60(3):371-381
The radiochemical degradation of bisphenol A polysulfone was investigated under a γ‐ray dose rate of 24 kGy h?1 up to 30.7 MGy total absorbed dose at 60 °C using gel permeation chromatography, sol–gel analysis, glass transition and rheometry measurements, and oxidation profile measurements by microscopy coupled with Fourier transform infrared analysis in attenuated total reflectance mode. Thin (200 µm) and thick (2 mm) samples were compared. Thin samples undergo mainly chain scissions whereas thick ones undergo mainly crosslinking. The thickness of oxidized layers and, radiochemical yields for chain scissions, crosslinking, oxygen absorption and radical formation were tentatively determined from experimental data in order to determine the influence of oxidative processes on radiochemical ageing and to establish the nature of the crosslinking reactions. Copyright © 2010 Society of Chemical Industry 相似文献
243.
Marina I. Nikolaeva Tatiana B. Mikenas Mikhail A. Matsko Ludmila G. Echevskaya Vladimir A. Zakharov 《应用聚合物科学杂志》2010,115(4):2432-2439
Experimental data on the molecular weight distribution (MWD) of polyethylene (PE) produced over a broad number of Ziegler‐Natta catalysts differing in composition and preparation procedure are presented. These catalysts include nonsupported TiCl3 catalyst, four types of supported titanium‐magnesium catalysts (TMC) differing in the content of titanium and the presence of various modifiers in the composition of the support, and a supported catalyst containing VCl4 as an active component instead of TiCl4. The studied catalysts produce PE with different molecular weights within a broad range of polydispersity (Mw/Mn = 2.8–16) under the same polymerization conditions. The heterogeneity of active sites of these catalysts was studied by deconvolution of experimental MWD curves into Flory components assuming a correlation between the number of Flory components and the number of active site types. Five Flory components were found for PE produced over nonsupported TiCl3 catalysts (Mw/Mn = 6.8), and three–four Flory components were found for PE produced over TMC of different composition. A minimal number of Flory components (three) was found for PE samples (Mw/Mn values from 2.8 to 3.3) produced over TMC with a very low titanium content (0.07 wt %) and TMC modified with dibutylphtalate. It was shown that five Flory components are sufficient to fit the experimental MWD curve for bimodal PE (Mw/Mn = 16) produced over VMC. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010 相似文献
244.
Galina A Polotskaya Alexandra Yu Pulyalina Valeriia A Rostovtseva Alexander M Toikka Natalia N Saprykina Ludmila V Vinogradova 《Polymer International》2016,65(4):407-414
Star‐shaped macromolecules with six arms of polystyrene grafted onto a fullerene C60 core, or fullerene‐containing polystyrene (FPS), were used for the modification of poly(phenylene oxide) (PPO) and the preparation of a dense thin‐film membrane. The membrane structure was studied using scanning electron microscopy. The effect of FPS modifier on membrane density and mass transfer of methanol and ethylene glycol through the membrane was studied. Sorption and pervaporation tests were used to determine degree of sorption, diffusion coefficients, flux through the membrane and separation factor. In the pervaporation of a methanol–ethylene glycol mixture over the concentration range of 10–30 wt% methanol in the feed, all membranes showed high affinity to methanol. The separation factor reached a maximum at 5 wt% FPS in the membrane. The PPO/FPS membranes exhibit the best separation properties when the feed is enriched with ethylene glycol. © 2016 Society of Chemical Industry 相似文献
245.
Ketan Kuperkar Ludmila Abezgauz Kamlesh Prasad P. Bahadur 《Journal of surfactants and detergents》2010,13(3):293-303
Self-assembly of cetyltrimethylammonium bromide (CTAB) in aqueous solution, in the presence of two inorganic salts viz, NaNO3 and NaClO3 was investigated by steady-state fluorescence, electrical conductance, surface tension, viscosity, dynamic light scattering (DLS) and cryogenic transmission microscopy (cryo-TEM). The counterions located at short enough distances to CTA+ micellar surface experience a very strong electrostatic attraction and thus become condensed. This counterion condensation plays a significant role in deciding the effective charge on the micelle, their screening interaction and structural transition of the micelles. In the present work, the probable mechanism of the salts' action in aqueous solution of CTAB is explained. The critical micelle concentration (CMC), area per molecule (Å2), micelle hydrodynamic diameter (D h ), and aggregation number (N agg) of CTAB micelles in the absence and presence of the salts are reported. The addition of both salts followed the lyotropic series and showed a remarkable decrease in CMC. A detailed investigation of the structural transitions from spherical to rod or even to entangled wormlike structures is presented from cryoTEM. 相似文献
246.
Boris A. Katsnelson Larisa I. Privalova Vladimir B. Gurvich Oleg H. Makeyev Vladimir Ya. Shur Yakov B. Beikin Marina P. Sutunkova Ekaterina P. Kireyeva Ilzira A. Minigalieva Nadezhda V. Loginova Marina S. Vasilyeva Artem V. Korotkov Eugene A. Shuman Larisa A. Vlasova Ekaterina V. Shishkina Anastasia E. Tyurnina Roman V. Kozin Irene E. Valamina Svetlana V. Pichugova Ludmila G. Tulakina 《International journal of molecular sciences》2013,14(2):2449-2483
Stable suspensions of nanogold (NG) and nanosilver (NS) with mean particle diameter 50 and 49 nm, respectively, were prepared by laser ablation of metals in water. To assess rat’s pulmonary phagocytosis response to a single intratracheal instillation of these suspensions, we used optical, transmission electron, and semi-contact atomic force microscopy. NG and NS were also repeatedly injected intraperitoneally into rats at a dose of 10 mg/kg (0.5 mg per mL of deionized water) three times a week, up to 20 injections. A group of rats was thus injected with NS after oral administration of a “bioprotective complex” (BPC) comprised of pectin, multivitamins, some amino acids, calcium, selenium, and omega-3 PUFA. After the termination of the injections, many functional and biochemical indices and histopathological features of the spleen, kidneys and liver were evaluated for signs of toxicity, and accumulation of NG or NS in these organs was measured. From the same rats, we obtained cell suspensions of different tissues for performing the RAPD test. It was demonstrated that, although both nanometals were adversely bioactive in all respects considered in this study, NS was more noxious as compared with NG, and that the BPC tested by us attenuated both the toxicity and genotoxicity of NS. 相似文献
247.
It is generally assumed that short-chain organoclays are better sorbents for non-ionic organic compounds than are the long-chain organoclays. We believe that the above statement is correct only for relatively hydrophilic or slightly hydrophobic compounds and that the opposite should be true for highly hydrophobic compounds, namely, that long-chain organoclays are expected to be superior to the short-chain analogs for sorption of highly hydrophobic materials.To verify our hypothesis, the sorption of six compounds with a range of log Kow values from 2.5 to 6 was studied on tetramethyltriammonium-(TMA) and octadecyltrimethylammonium-(ODTMA) bentonite, representing short- and long-chain organoclays, respectively. Compounds with low or medium hydrophobicities (log Kow 2.5–3.8) were more strongly sorbed on the short-chain organoclay, whereas the more hydrophobic compounds (log Kow 5.2–6.1) were better sorbed on the long-chain organoclay, in agreement with our hypothesis.The efficacy of organoclays in removing organic pollutants from the effluent of a pesticide producing plant was evaluated. Pesticide sorption from the wastewater was studied on both types of organoclays. It was found that both organoclays were able to remove organic pollutants from industrial wastewater, but solute uptake by short-chain organoclays was strongly depressed by competition, while long-chain organoclays were only slightly affected, if at all, by the presence of competing solutes in the industrial wastewater. 相似文献
248.
Nataliya Taran Ludmila Batsmanova Yevheniya Konotop Alexander Okanenko 《Nanoscale research letters》2014,9(1):354
The content of metal elements in plant tissues of 10-day wheat seedlings after seed pre-treatment and foliar treatment with non-ionic colloidal solution of metal nanoparticles (Fe, Mn, Cu, Zn) was determined by an atomic absorption spectrometer. It was shown that metal nanoparticles due to their physical properties (nanoscale and uncharged state) were capable of penetrating rapidly into plant cells and optimizing plant metabolic processes at the early stages of growth and development. 相似文献
249.
Ludmila Mahnicka-Goremikina Ruta Svinka Visvaldis Svinka 《Ceramics International》2018,44(14):16873-16879
Porous mullite-corundum refractory ceramics were produced by a patented slurry slip casting method from compositions based on commercially available α-Al2O3 and γ-Al2O3, fused SiO2 and kaolin. Pores were formed as a result of a chemical reaction of aluminium with water. The influence of usage of raw materials and doping additives such as micro-size ZrO2 and WO3 on the sintering temperature, formation of crystalline phases, linear thermal expansion, thermal conductivity and thermal shock resistance of mullite-corundum ceramic was studied. The best thermal shock resistance and, simultaneously, lower thermal conductivity was achieved for the samples doped with WO3. This was due to the influence of micro-sized WO3 on the change in γ-Al2O3 modification to α-Al2O3 and on the structure of mullite ceramics. 相似文献
250.
Marie Bi
íkov Ludmila M
ov Dobroslava Jandov Zdenk Tískala Martin Hill 《International journal of molecular sciences》2021,22(12)
The aging of human populations, including those in Europe, is an indisputable fact. The challenge for the future is not simply prolonging human life at any cost or by any means but rather extending self-sufficiency and quality of life. Even in the most advanced societies, the eternal questions remain. Who will take care of the older generations? Will adult children’s own circumstances be sufficient to support family members as they age? For a range of complex reasons, including socioeconomic conditions, adult children are often unable or unwilling to assume responsibility for the care of older family members. For this reason, it is imperative that aging adults maintain their independence and self-care for as long as possible. Movement is an important part of self-sufficiency. Moreover, movement has been shown to improve patients’ clinical status. At a time when the coronavirus pandemic is disrupting the world, older people are among the most vulnerable. Our paper explores current knowledge and offers insights into the significant benefits of movement for the elderly, including improved immunity. We discuss the biochemical processes of aging and the counteractive effects of exercise and endogenous substances, such as vitamin D. 相似文献