Synthesis of Mesoporous Lithium Titanate Thin Films and Monoliths as an Anode Material for High‐Rate Lithium‐Ion Batteries

Mesoporous Li₄Ti₅O₁₂ (LTO) thin film is an important anode material for lithium‐ion batteries (LIBs). Mesoporous films could be prepared by self‐assembly processes. A molten‐salt‐assisted self‐assembly (MASA) process is used to prepare mesoporous thin films of LTOs. Clear solutions of CTAB, P123, LiNO₃, HNO₃, and Ti(OC₄H₉)₄ in ethanol form gel‐like meso‐ordered films upon either spin or spray coating. In the assembly process, the CTAB/P123 molar ratio of 14 is required to accommodate enough salt species in the mesophase, in which the Li^I/P123 ratio can be varied between molar ratios of 28 and 72. Calcination of the meso‐ordered films produces transparent mesoporous spinel LTO films that are abbreviated as Cxx‐yyy‐zzz or CAxx‐yyy‐zzz (C=calcined, CA=calcined–annealed, xx=Li^I/P123 molar ratio, and yyy=calcination and zzz=annealing temperatures in Celsius) herein. All samples were characterized by using XRD, TEM, N₂‐sorption, and Raman techniques and it was found that, at all compositions, the LTO spinel phase formed with or without an anatase phase as an impurity. Electrochemical characterization of the films shows excellent performance at different current rates. The CA40‐350‐450 sample performs best among all samples tested, yielding an average discharge capacity of (176±1) mA h g^?1 at C/2 and (139±4) mA h g^?1 at 50 C and keeping 92 % of its initial discharge capacity upon 50 cycles at C/2.     

Effects of ELF Magnetic Field in Combination with Iron(III) Chloride (FeCl3) on Cellular Growth and Surface Morphology of Escherichia coli (E. coli)

This study investigated the effects of extremely low frequency (ELF) magnetic field with/without iron(III) chloride (FeCl₃) on bacterial growth and morphology. The ELF exposures were carried out using a pair of Helmholtz coil-based ELF exposure system which was designed to generate 50 Hz sinusoidal magnetic field. The field was approximately uniform throughout the axis of the coil pair. The samples which were treated or non-treated with different concentrations FeCl₃ were exposed to 50 Hz, 2 millitesla (mT) magnetic field for 24 h. ELF effect on viability was assessed in terms of viable colony counts (in colony-forming unit per milliliter) with the standard plate count technique. Scanning electron microscopy was used to investigate the magnetic field effect on surface morphology of Escherichia coli. No significant results were seen in terms of cell viability between ELF and sham-exposed bacterial strains. Similarly, FeCl₃ treatment did not change cell viability of E. coli samples. However, we observed some morphological changes on E. coli cell surfaces. Pore formations and membrane destruction were seen on the surface of 24 h ELF field-exposed cells. We concluded that ELF magnetic field exposure at 2 mT does not affect cell viability; however, it may affect bacterial surface morphology.     

Approximation in statistical sense to <Emphasis Type="Italic">n</Emphasis>-variate B-continuous functions by positive linear operators

Our primary interest in the present paper is to prove a Korovkintype approximation theorem for sequences of positive linear operators defined on the space of all real valued n-variate B-continuous functions on a compact subset of the real n-dimensional space via statistical convergence. Also, we display an example such that our method of convergence is stronger than the usual convergence.     

Modelling and calculation of risk due to radon concentration in residential houses,Nicosia, Cyprus

Journal of Radioanalytical and Nuclear Chemistry - Lifetime lung cancer risks were computed using EPA/BEIR-VI models employing recent North Cyprus statistics (4-year averages from 2012 to 2016) to...     

A Korovkin-type theorem for double sequences of positive linear operators via power series method

In this paper, using power series method we obtain a Korovkin type theorem for double sequences of real valued functions defined on a compact subset of \(\mathbb {R}^{2}\)(the real two-dimensional space). We also present an example that satisfies our theorem. Finally, we calculate the rate of convergence.     

Influence of Guanidinium Salts and Other Ionic Liquids on the Three‐Component Aza‐Diels?Alder Reaction

The three‐component reaction of aniline, benzaldehyde, and dienophiles such as 2,3‐dihydrofuran, ethyl vinyl ether, 2,3‐dihydropyran, and cyclopentadiene can be promoted by ionic liquids like imidazolium salts and guanidinium salts under thermal as well as microwave conditions. The chemical yield as well as the diastereoselectivity of the Povarov reaction strongly depend on the ionic liquid employed. The guanidinium salts can be recycled and reused several times without loss of reactivity.     

Preparation and the proton conductivity of chitosan/poly(vinyl phosphonic acid) complex polymer electrolytes

This study describes the preparation and proton conductivity of novel polymer complex electrolytes consisting of chitosan and poly(vinylphosphonic acid), PVPA. The materials were prepared via in situ polymerization of vinyl phosphonic acid in the presence of chitosan at various monomer feed ratios with respect to d-glucosamine repeat unit. Homogeneous materials were produced and they were extensively characterized for their compositions by elemental analysis (EA), thermal properties by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) and the morphology by X-ray diffraction (XRD). The complexation of chitosan/PVPA via proton exchange reactions was confirmed by Fourier transform infrared (FT-IR). The methanol permeability of CHPVPA₅ was lower than Nafion^® 115. The water/methanol uptake was measured and the results showed that solvent absorption of the materials increased with increasing PVPA content in the matrix. The temperature dependence of the proton conductivity of the complex electrolytes follows VTF behavior at higher x. Proton conductivity of CHPVPA₅ was measured to be approximately 3 × 10⁻⁵ S/cm at 120 °C in the anhydrous state.     

Photochemical reactions of [(η 5-C5H5)Mn(CO)3] with Ph2P(S)(CH2) n P(S)Ph2 [n=1, dppm(S)2; 2, dppe(S)2; 3, dppp(S)2]

Six new complexes, Mn(CO)( ⁵-C₅H₅){Ph₂P(S)(CH₂) _n P(S)Ph₂}] (1a–3a) [(1a), n=1; (2a), n=2; (3a), n=3] and [Mn₂(CO)₄( ⁵-C₅H₅)₂(cis--Ph₂P(S)(CH₂) _n P(S)Ph₂)] (1b–3b) [(1b), n=1; (2b), n=2; (3b), n=3] have been synthesized by the photochemical reaction of [( ⁵-C₅H₅)Mn(CO)₃] with Ph₂P(S)(CH₂) _n P(S)Ph₂ [n=1, dppm(S)₂; 2, dppe(S)₂; 3, dppp(S)₂]. The complexes have been characterized by elemental analysis, mass spectroscopy, f.t.-i.r. and ³¹P–[¹H]-n.m.r. spectroscopy. The spectroscopic studies reveal that coordination of the ligand iscis-chelate bidentate in [Mn(CO)( ⁵-C₅H₅){Ph₂P(S)(CH₂) _n P(S)Ph₂}] (1a–3a) and cis-bridging bidentate between two metals in [Mn₂(CO)₄( ⁵-C₅H₅)₂(cis--Ph₂P(S)(CH₂) _n P(S)Ph₂)] (1b–3b).