F,Cl, Br Doped Ge44 and Al22P22 Nanocages As Anode Electrode Materials of Li,Na, and K ion Batteries

Russian Journal of Physical Chemistry A - In this study, the potential of Ge44 and Al22P22 as anode electrodes of Li-ion, Na-ion, and K-ion batteries were investigated via density functional...     

Chemically functionalized silica nanoparticles‐based solid‐phase extraction for effective pre‐concentration of highly toxic metal ions from food and water samples

In this research study, an efficient solid‐phase extraction procedure based on a new organometallic, effective, eco‐friendly and bio‐degradable nanoadsorbent was firstly introduced for influential pre‐concentration of Cu(II), Zn(II), Pb(II), Cd(II) and Mn(II) ions from food and water samples followed by flame atomic absorption spectrophotometric determination. This safe adsorbent consisted of silica nanoparticles chemically functionalized with di‐ethylen tri‐amine (SiO₂@NH₂NPs); easily prepared via an effective and simple approach. Characterization of SiO₂@NH₂NPs was subsequently implemented via SEM, FT‐IR and XRD; certifying high quality of the modified nanoadsorbent in terms of size, shape and surface functional groups. The effects of the main factors on the extraction efficiency were then optimized. Efficient extraction of the analytes of interest at neutral media accompanied with the aid of a bio‐compatible organometallic nanoadsorbent can be considered as valuable advantages of the proposed approach. In the optimum conditions, calibration graphs were linear in the range of 4–700 μg l^?1, with higher correlation coefficients than 0.997 and limits of detection of 1.45–4.10 ng ml^?1. The enrichment factor values were found to be in the span of 120–400. The resultant extraction recovery values were satisfactory; possessing the proper relative standard deviation (%, n  =  5) values of 2.05–4.28%.     

On m-th root metrics with special curvature properties

In this Note, we prove that every m-th root Finsler metric with isotropic Landsberg curvature reduces to a Landsberg metric. Then, we show that every m-th root metric with almost vanishing H-curvature has vanishing H-curvature.     

Study of Oxidation of Carbon Monoxide on the Surface of Sn-doped Carbon Nanotube

In recent years, the discovery of suitable catalyst to the oxidation of carbon monoxide(CO) is a major concern in industry. In present study, in the first step the carbon nanotube(CNT) with Sn was doped and the surface of Sn-CNT via O_2 molecule was activated. In the second step the CO oxidation on the surface of Sn-CNT via Langmuir Hinshelwood(LH) and Eley Rideal(ER) mechanisms was investigated. Results show that O_2-Sn-CNT can oxidize the CO molecule via Sn-CNT-O-O* + CO → Sn-CNT-O-O*-CO → Sn-CNT-O* + CO_2 and Sn-CNT-O* + CO → Sn-CNT + CO_2 reactions. Results show that CO oxidation on activated Sn-CNT surface via the ER mechanism has lower energy barrier than LH mechanism. Finally, calculated parameters reveal that activated Sn-CNT is an acceptable catalyst with high potential to the oxidation of CO molecule.     

Damping Characterization and Viscoelastic Behavior of Laminated Polymer Matrix Composites Using a Modified Classical Lamination Theory

The damping property of materials can be defined as the ratio of dissipated energy over the total strain energy during the loading–unloading process, called the specific damping capacity (SDC). In this study, in order to characterize the damping properties of materials, a test plan in designed to extract the SDC of a single layer composite from hysteresis data. The theory of linear viscoelasticity incorporates a varying Young’s Modulus by using a complex stiffness modulus. Considering different lay-ups, the modified classical lamination plate theory is modified to represent both stiffness and SDC of laminates. The results are compared with experimental results for symmetric laminated specimen. This evaluation shows a very good agreement between theoretical and experimental results in the range of low frequency loading from 0.2 to 4 Hz. The complex compliance matrix changes the governing equation in to a complex form which contains both stiffness and damping properties.     

Surface tension of non-ideal binary and ternary liquid mixtures at various temperatures and p = 81.5 kPa

Experimental surface tensions for binary mixtures (1,2-ethandiol + water), (1,2-ethandiol + acetonitrile), and (acetonitrile + water) at temperatures of 283.15 K, 298.15 K, and 308.15 K and the ternary mixture (1,2-ethandiol/water/acetonitrile) at 298.15 K have been measured with the Du Noüy ring tensiometer. The surface tension of the above mentioned binary and ternary systems were correlated with empirical and thermodynamic based models. The methods of Pando et al. and Ku et al. were used to correlate the ternary surface tension data. The Fu et al., Kalies et al. and Wang et al. models were also applied to predict surface tension in the ternary system. The mean average absolute deviations obtained from the comparison of experimental and calculated surface tension values for ternary system with three models are less than 2.4%, which leads to concluding that these models show a good accuracy in different situations in comparison with other predictive equations.     

A Quantum Chemical Investigation on the Antioxidant Activity of Licoisoflavone Derivatives

In this paper,21 substituents with various electron donating and electron withdrawing characters were placed in the available positions of Licoisoflavone in order to study their effect on the three O–H bond dissociation enthalpies and ionisation potential via DFT/B3LYP method.Results show that the B-ring is more important than the A-ring from the BDE and IP point of view because the radical structure formed after hydrogen atom abstraction from the 4-OH group can be stabilized by the resonance between the three rings.The results show that intramolecular hydrogen bonding effects are able to considerably stabilize the parents and radicals.The NBO analysis results also confirmed the intramolecular hydrogen bond stabilization.The formation of strong intramolecular hydrogen bonds and suitable spin density distributions in several radicals result in low BDE and IP values.The calculated BDE and IP values have been correlated with Hammett constants.The found dependencies are suitably linear,which can be important for the synthesis of novel antioxidants based on Licoisoflavone.     

Synthesis and Characterization of Novel Poly-thiophene-nanoporous Silica and its Application for Mercury Removal from Waste Waters

In this work, MCM-41 (Mobil Composition of Matter number 41) nanoporous silica has been synthesized and characterized by X-ray powder diffraction and IR spectroscopy. In the next step, poly-thiophene was coated on the nanoporous silica in order to increase its surface area. This composite was characterized by X-Ray powder diffraction, High resolution transmission electronic microscopy micrograph (HRTEM), elemental analysis (CHNS) and Thermal analysis (TG/DTA). The application of this composite was investigated in mercury ions removal from waste water prior to determination by inductively coupled plasma atomic emission spectroscopy (ICP-OES). In order to investigate the effect of nanoporous structure on the efficiency of this composite, the same composite without porous structure has been synthesized and the results were compared.     

Reconfigurable T‐junction DNA Origami

DNA self‐assembly allows the construction of nanometre‐scale structures and devices. Structures with thousands of unique components are routinely assembled in good yield. Experimental progress has been rapid, based largely on empirical design rules. Herein, we demonstrate a DNA origami technique designed as a model system with which to explore the mechanism of assembly. The origami fold is controlled through single‐stranded loops embedded in a double‐stranded DNA template and is programmed by a set of double‐stranded linkers that specify pairwise interactions between loop sequences. Assembly is via T‐junctions formed by hybridization of single‐stranded overhangs on the linkers with the loops. The sequence of loops on the template and the set of interaction rules embodied in the linkers can be reconfigured with ease. We show that a set of just two interaction rules can be used to assemble simple T‐junction origami motifs and that assembly can be performed at room temperature.