Anomaly in mixing properties of lithium–magnesium liquid alloy

The concentration dependent asymmetry in mixing properties of LiMg liquid alloys at 1000?K has been investigated on the basis of regular associated solution model. The analysis suggests that heterocoordination leading to the formation of chemical complex Li₂Mg is likely to exist in the melt.     

The effect of Er3+-ion concentration on the Er3+ : 4I13/2 → 4I15/2 transition in tellurite glasses

The effect of Er³⁺ concentration on the Er³⁺?:?⁴I_13/2?→?⁴I_15/2 emission in tellurite glasses has been investigated. The full width at half-maximum increased with the increasing concentration of Er₂O₃ in tellurite glasses. The effect of local structure of Er³⁺ ions and related spectroscopic changes are taken into account to explain the line broadening. Inhomogeneous broadening due to the distribution of crystal field around the Er³⁺ ion has little effect on the absorption spectra. Highly efficient energy trapping between the ions was identified from the time-resolved analysis of the fluorescence decay and is found to be responsible for the extended lifetime at intermediate concentrations of Er³⁺ ions in tellurite glasses. The effect of temperature on spectral line shape has been determined for analysing the contribution of Boltzmann population on line broadening. The increased population of the overlying Stark sublevels at the ⁴I_13/2 energy level via direct pumping and/or interaction between Er³⁺ ions were also found to be significant for enhancement in spectral line shape at higher concentrations of Er³⁺ ions in tellurite glasses. It was observed that at higher concentrations of Er³⁺ ions in glass also enhance the local symmetry of ions, which is apparent from the absorption band of the Er³⁺?:?⁴I_15/2?→?²H_11/2 hypersensitive transition.     

Infinite flocks of a quadratic cone

In this article, we construct some infinite analogues of the Fisher flocks. We also consider maximal partial flocks which may be constructed in several ways. In particular, we show that any derivation of a flock inPG(3,K), forK a full field, produces either a flock or a maximal partial flock. We provide constructions which produce maximal partial flocks or maximal partial spreads.In memoriam, Giuseppe TalliniThis article was written while the authors were visiting the Ricco Institute during June of 1994 and was partially supported by Glasgow-Caledonian University. Also, the authors are indebted to Christian Boltanski,D — S, in the writing of this article.The authors also are indebted to the referee for helpful suggestions with regard to this article.     

Breit-Pauli energy levels and radiative lifetimes in neutral chlorine

Breit-Pauli Energy levels, oscillator strengths and transition probabilities for all the transitions in Cl I between the fine structure levels of 3s² 3p⁵, 3s² 3p⁴3d, 3s² 3p⁴4s and 3s²3p⁴4p states are calculated using extensive configuration interaction (CI) wave functions. We have also determined the lifetimes of 3s² 3p⁴3d, 3s² 3p⁴4s and 3s² 3p⁴4p levels. The relativistic effects are included through Breit-Pauli approximation via spin-orbit, Darwin and mass correction terms. Prior to the calculations of the oscillator strengths and transition probabilities, we fine-tune the CI coefficient using experimental energies. Our results are compared with experimental and other available theoretical data. The calculated energy levels are in close agreement with most of the NIST compiled data. We predict new lifetime data for several levels where no other theoretical and/or experimental results are available, which will form the basis for the future experimental work. Electronic supplementary material Online Material     

Highly active and reusable catalyst from Fe-Mg-hydrotalcite anionic clay for Friedel-Crafts type benzylation reactions

Fe-Mg-hydrotalcite (Mg/Fe = 3) anionic clay with or without calcination (at 200–800‡C) has been used for the benzylation of toluene and other aromatic compounds by benzyl chloride. Hydrotalcite before and after its calcination was characterized for surface area, crystalline phases and basicity. Both the hydrotalcite, particularly after its use in the benzylation reaction, and the catalyst derived from it by its calcination at 200–800‡C show high catalytic activity for the benzylation of toluene and other aromatic compounds. The catalytically active species present in the catalyst in its most active form are the chlorides and oxides of iron on the catalyst surface.     

Quantitative determination of saroglitazar,a predominantly PPAR alpha agonist,in human plasma by a LC–MS/MS method utilizing electrospray ionization in a positive mode

A sensitive LC–MS/MS method was developed and validated for quantitation of saroglitazar using turboion spray interface with positive ion mode. A liquid–liquid extraction, with a mixture of dichloromethane and diethyl ether, was employed for the extraction of saroglitazar and glimepiride (IS) from human plasma. The chromatographic separation was achieved using an ACE‐5, C₁₈ (4.6 × 100 mm) column with a gradient mobile phase comprising acetonitrile and ammonium acetate buffer with trifluoracetic acid in purified water. Both analytes were separated within 10 min with retention times of 4.52 and 2.57 min for saroglitazar and IS, respectively. Saroglitazar quantitation was achieved by the summation of two MRM transition pairs (m/z 440.2 to m/z 366.0 and m/z 440.2 to m/z 183.1), while that of IS was achieved using transition pair m/z 491.3 to m/z 352.0. The calibration standards of saroglitazar showed linearity from 0.2 to 500 ng/mL, with a lower limit of quantitation of 0.2 ng/mL. The biases for inter‐ and intra‐batch assays were ?7.51–1.15% and ?11.21 to ?3.25%, respectively, while the corresponding precisions were 5.04–8.06% and 1.53–7.68%, respectively. The developed method was used to monitor the plasma concentrations of saroglitazar in clinical samples.     

Assessment of the doses due to natural radionuclide in the green leafy vegetables of Domiasiat,Meghalaya India

A radiation dose assessment exercise was carried out for the Ipomea batata, Allium sativum, Dacaus carota, and Solanum tuberosum due to naturally available radionuclide ⁴⁰K, ²³⁸U and ²³²Th in the Domiasiat area of Meghalaya. The concentration of radionuclides in biota as well as corresponding soil was measured by precipitation method using NaI detector for continuous 12 months. Transfer factor was calculated and was, for ⁴⁰K(3.96E−05, 3.40E−05, 3.40E−05, 2.70E−05), for ²³²Th(3.94E−05, 3.20E−05, 3.20E−054.93E−05), for ²³⁸U(3.60E−05, 3.89E−05, 3.85E−054.57E−05), respectively in each biota due to each radionuclide. The point source dose distribution (source ↔ target) hypotheses was applied for the consideration of absorbed fraction. The generated data were modeled using the FASSET method and obtained dose was 8.42E−03, 8.36E−03, 7.78E−03, 7.74E−03 μGy h⁻¹, respectively and finally compared with the IAEA and UNSCEAR dataset for screening level dose for terrestrial biota.     

Microstrip patch array antenna on photonic crystal substrate at terahertz frequency

Recent advancement in the fabrication and packaging technology has led to the micrometer and nanometer-scale device modeling. This technological development and subsequent reduction in the dimension of devices like modulators, detectors and antennas has brought a thought of increasing the operating frequency of the system to the extent of sub-millimeter wavelength. In the view of the technical breakthrough in the area of fabrication and packaging, we have explored a printed antenna array on the photonic crystal in the terahertz spectrum in this paper. An equivalent circuit model of the antenna has been proposed and a methodology to investigate various electrical parameters is discussed. Tunable parameters of the structure have been explored to optimize the electrical performance of the proposed antenna. The analysis is also compared by using two simulators: (a) CST Microwave Studio based on finite integral technique and (b) Ansoft HFSS based on finite element method. The effect of the photonic crystal as substrate to enhance the gain of this kind of the antenna has also been demonstrated. The gain, directivity, front-to-back ratio (F/B ratio), and the radiation efficiency of the proposed antenna at 600 GHz is 16.88 dBi, 17.19 dBi, 14.77 dB and 89.72%, respectively. Finally, the performance of the antenna has been compared with the reported literature.