Research on the electrochemistry of oxygen ion conductors in the former Soviet Union. I. ZrO2-based ceramic materials

Developments of solid electrolytes and mixed conductors based on stabilized zirconia in the former Soviet Union are reviewed. Primary attention is given to experimental data on high-conducting electrolytes, mixed conductors obtained by doping zirconia with transition metal oxides, oxygen exchange and oxygen permeation processes, as well as properties of metal electrodes in contact with the stabilized zirconia. Received: 26 March 1998 / Accepted: 4 June 1998     

Ultrashort self-similar periodic waves and similaritons in an inhomogeneous optical medium with an external source and modulated coefficients

Nonlinear Dynamics - In this paper, we use the similarity transformation to reduce the generalized higher-order nonlinear Schrödinger equation with space- and time-modulated coefficients...     

Graphene‐mesoporous anatase TiO2 nanocomposite: A highly efficient and recyclable heterogeneous catalyst for one‐pot multicomponent synthesis of benzodiazepine derivatives

The potential to bias chemical reaction pathways is a significant goal for physicists and material researchers to design revolutionary materials. Recently, two‐dimensional materials have appeared as a promising candidate for exploring novel catalyst activity in organic reaction. In this context, herein we report an easy and efficient synthesis of substituted benzodiazepines in high yields through the graphene‐based mesoporous TiO₂ nanocomposite (Gr@TiO₂ NCs) catalyst. To validate the merits of the Gr@TiO₂ NCs as a catalyst, we have also designed TiO₂ nanoparticle (NPs) under similar conditions. Successful comprehension realization of Gr@TiO₂ NCs and TiO₂ NPs were concluded from the XRD, SEM, HR‐TEM, EDS elemental mapping, FT‐IR, Raman, UV–Vis and TGA analysis. Gr@TiO₂ NCs has the propitious catalyst performance (~98%) over the TiO₂ NPs (~77%), which could be scrutinized in terms of graphene support toward the TiO₂ NPs and enable the large contact area between graphene and TiO₂ NPs. Incorporated graphene maintaining TiO₂ as a catalytically active and attracting electron to site isolation, as well as protecting TiO₂ from oxidative degradation during the reaction. Moreover, the role of graphene is suggested to prolonged reaction duration, yield and unaltered throughout the reaction because of the π‐π interaction between graphene and TiO₂ NPs. Additionally, the catalyst is recycled by filtration and reprocessed six times without having a significant loss in its catalytic activity.     

Improved molecular weight control in ring‐opening metathesis polymerization reactions in organic and aqueous media using N‐heterocyclic carbene–ruthenium arene/alkyne catalyst systems

A binary catalytic system, RuCl₂(N‐heterocyclic carbene)(p‐cymene)/alkyne, was developed for improved molecular weight control in ring‐opening metathesis polymerization (ROMP) reactions of norbornene derivatives in organic and aqueous media. Monometallic ruthenium arene compounds were activated using aryl and aliphatic terminal alkynes to form highly active metathesis species. The effects of alkyne structure and concentration on the overall catalytic activity were systematically investigated. The catalytic activity of the metathesis active species can be tuned by varying alkyne substituents. Also, the initiation rate of the ROMP reaction can be tuned by increasing the alkyne‐to‐Ru ratio. ROMP polymers with a wide range of molecular weights (91–832 kDa) were isolated in organic media, whereas polymers with a molecular weight range of 110–280 kDa with average particle sizes of 150–250 nm were isolated in aqueous media. Copyright © 2016 John Wiley & Sons, Ltd.     

Metal-DNA Interaction in vivo and in vitro Investigation

The content of various metals Ni, Cr,Cd, Pb, Fe, Cu, Mg, Ca, Zn were determined in the DNA samples from cells C3HA mice liver and ascitic hepatoma 22A by the method ICP-AES. The results are presented in Table 1.     

Eco‐friendly synthesis of benzoxazepine and malonamide derivatives in aqueous media

A special, efficient and reusable heterogeneous catalytic system is reported for the one‐pot three‐component synthesis of a series of malonamide and 2,3,4,5‐tetrahydrobenzo[b][1,4]oxazepine derivatives in the presence of a heterogeneous material composed of MCM‐48/H₅PW₁₀V₂O₄₀ in aqueous media and at room temperature. The products were identified using physical data (melting points) by comparison with those reported in the literature. Also, the structures of the new compounds were characterized by means of infrared, ¹H NMR, ¹³C NMR and CHN analyses. Copyright © 2016 John Wiley & Sons, Ltd.     

New approaches to characterize polymeric oil additives in solution based on pyrene excimer fluorescence

Maleated polyolefins (MaPOs) such as maleated ethylene propylene copolymers or polyisobutylene terminated at one end with a succininic anhydride can be used as polymeric dispersants in engine oils after reaction with polyamines while unmodified EP copolymers improve the viscosity index of oils. MaPOs can also be labeled with pyrene derivatives to generate pyrene‐labeled polyolefins (PyLPOs) as fluorescent mimics of oil additives and pyrene excimer fluorescence (PEF) can be applied to probe their behavior in solution. This review describes new methodology that was recently implemented to characterize the complex fluorescence signal emitted by PyLPOs by using steady‐state and time‐resolved fluorescence. This methodology enables one to gain quantitative information about the level of clustering of the succinic pendants along a maleated polyolefins and intra‐ and intermolecular aggregation of polyolefins in solution. Such information is relevant to scientists aiming to characterize polymeric oil additives used in engine oil. © 2016 Wiley Periodicals, Inc. J. Polym. Sci., Part B: Polym. Phys. 2017 , 55, 7–18