L‐Proline‐Catalyzed Asymmetric Direct Aldol Reaction of Heteroaromatic Aldehydes and Acetone: Improvement of Catalytic Efficiency in Ionic Liquid bmim [BF4]

l‐proline in bmim [BF₄] ionic liquid has been successfully used as an efficient and reusable catalyst for the direct asymmetric aldol reaction of acetone with different heteroaromatic aldehydes to afford higher selectivity of the aldol products with good enantioselectivity.     

Thermoelectric power of cerium up to 6 GPa

The thermoelectric power (TEP) of cerium has been measured up to 6 GPa. The results have been interpreted using the theories developed by Blandin et. al. and Hirst.     

A new family of discrete Painlevé equations and associated linearisable systems

We derive discrete systems which result from a second, not studied up to now, form of the q-P_VI equation. The derivation is based on two different procedures: “limits” and “degeneracies”. We obtain several new discrete Painlevé equations along with some linearisable systems. The parallel between the results for the standard form of q-P_VI and those of the new one is also established.     

Magnetic studies of Bi x Y3-x Fe5O12 fabricated using conventional method

A series of Bi substituted yttrium iron garnet (Bi-YIG) nanoparticles with nominal formula of Bi _x Y_3???x Fe₅O₁₂ in which x varied in steps of 0.0, 0.25 and 0.5 are prepared by conventional method. Vibration sample magnetometer (VSM) at Room temperature (RT) shows saturation magnetization decreases from 27.4 to 25.2 (emu/g) as x value increases from 0.0 to 0.5. Room temperature ⁵⁷Fe Mössbauer spectra are recorded for these series. The hyperfine field value for octahedral and tetrahedral of samples increases from 484 and 390 kOe to 491 and 397 kOe respectability, as Bi replaces Y in (Bi _x Y_3???x Fe₅O₁₂) atom with increasing x value. The effect of Bi^3?+? substitution for Y^3?+? on lattice constants, morphology and magnetic properties of pure YIG has been investigated.     

UV assisted low temperature nitridation and post deposition oxidation technique for hafnium oxide gate dielectric

An evaluation of a low temperature method (∼400 °C) for synthesis of nitrogen incorporated hafnia gate dielectric has been reported. This method is based on metal film growth in ammonia ambient and subsequent oxidation under ultraviolet (UV) irradiation. X-ray photoelectronic spectroscopy confirmed the presence of nitrided interface layer with a thickness of ∼12 ?. Equivalent oxide thickness values of around 11.5 ? and leakage current densities lower than 1 × 10⁻⁴ A/cm² at an operation voltage (−1 V) were achieved. The post deposition ultraviolet oxidation process was performed to check the interface oxidation resistance. The interface growth rate showed that as the interface bonding characteristics changed from Si-N to Si-O predominant bonding system of nitrogen incorporated films, the activation energy for oxygen diffusion changed from 18.0 kJ/mol to 9.8 kJ/mol and the activation energy of undoped hafnia films was 2.3 kJ/mol in every growth region.     

A convenient synthesis of methyl 2-hydroxy-4-oxo-4-(substituted phenyl) butanoates from malic acid

A synthesis of methyl 2-hydroxy-4-oxo-4-(substituted phenyl)butanoates has been accomplished using Friedel-Crafts acylation of substituted benzenes with 2-acetoxybutanoyl chloride.The key feature of this strategy is that various 4-arylbutanoates can be obtained conveniently,which are important intermediates for the synthesis of biologically active compounds including ACE inhibitors.     

PEG-SO_3H as catalyst for the Beckmann rearrangement and dehydration of oximes

Under mild conditions, conversion of a variety of ketoximes and aldoximes to their corresponding amides and nitriles proceeded in the presence of PEG-SO3H with high yields.     

Multiwalled Carbon Nanotubes: Adsorbent for Ruthenium from Aqueous Solution

Journal of Radioanalytical and Nuclear Chemistry - This paper describes the adsorption behavior of ruthenium on multi walled carbon nanotubes (MWCNTs) from aqueous solution. The adsorption behavior...     

Thallation of fluorenes: A kinetic and mechanistic study

The kinetics of thallation of fluorene with thallium triacetate (TTA) in HOAc-H₂SO₄ solutions led to the rate expression The rate of thallation is found to increase with increasing acid concentration, and a sixth-order dependence on [H₂SO₄] is observed. Decrease in solvent polarity increases the rate of thallation. The effect of substituents is in accord with the electrophilic substitution at an aromatic system. Thallation occurs at 4-position. A mechanism similar to aromatic bromination is proposed for the thallation of fluorene.