Single crystal EPR and optical studies of paramagnetic ions doped zinc potassium phosphate hexahydrate—Part I: Cu(II)—a case of orthorhombic symmetry

Single crystal electron paramagnetic resonance (EPR) studies on Cu(II) doped zinc potassium phosphate hexahydrate (ZPPH) were carried out at room temperature. The angular variation spectra in the three orthogonal planes indicate that the paramagnetic impurity has entered the lattice substitutionally in place of Zn(II) and the spin Hamiltonian parameters calculated from these spectra are g(xx) = 2.188, g(yy) = 2.032, g(zz) = 2.373, Axx = 50 G, Ayy = 65.0 G and Azz = 80 G. The g and A tensors were coincident and these values matched fairly well with the values obtained from powder spectrum. The bonding parameters have also been calculated.     

A mild and novel synthesis of functionalized fused imidazole analogues under environmentally benign reaction media

A mild and novel approach is described for the synthesis of functionalized fused imidazole analogues in solvent-free and catalyst-free condition in ionic liquid. The short reaction time, good isolated yields, generality and environmentally benign reaction media are the significant features of this protocol.     

Impulse free interconnection of dynamical systems

In this paper we address the problem that impulses might occur when a to-be-controlled plant is connected to a suitable controller. In the behavioral literature this issue is dealt when studying the so-called ‘regular feedback interconnection’ (RFI) of the plant and the controller behaviors. We address the question of when a given controlled behavior satisfying desired specifications can be obtained by RFI of the plant and some suitable controller. The paper presents an algorithm to construct a controller that yields the controlled behavior by RFI, if such a controller exists, and then parametrizes all such controllers. We extend the results to the more general case when all the to-be-controlled variables might not be available for interconnection. We show that any disturbances in the plant continue to remain free in the controlled behavior if and only if the interconnection is an RFI. This is also equivalent to the well-posedness of an interconnection. This paper also makes concrete the intuitive relation between absence of inadmissibility of initial conditions and RFI. A door closing mechanism is analysed in relation to the results in this paper.     

The Influence of the Radiofrequency Excitation and Conversion Pulses on the Lineshapes and Intensities of the Triple-Quantum MAS NMR Spectra of I = 3/2 Nuclei

A rigorous examination of the various multiple-quantum magic angle spinning sequences is carried out with reference to sensitivity enhancement in the isotropic dimension and the lineshapes of the corresponding MAS peaks in the anisotropic dimension. An echo efficiency parameter is defined here, which is shown to be an indicator of the performance aspects of the various sequences. This can be used in the design of further new experiments in this field. A consequence of such a systematic analysis has been the combination of a spin-lock pulse for excitation of multiple-quantum coherences and an amplitude-modulated pulse for their conversion to observable single-quantum coherences. This approach has resulted in an improved performance over other sequences with respect to both the anisotropic lineshapes and the isotropic intensities.     

Colour Adaptation in Three Fringe Photoelasticity

Three fringe photoelasticity (TFP) can give the total fringe order from a single colour isochromatic fringe field by suitably comparing the colour with a calibration specimen. The fringe order evaluation can be erroneous when the materials for the calibration specimen and the application specimen are different. This is because of the colour variation between the two materials. This is conventionally handled by preparing individual calibration tables for each application. A new methodology to tune the calibration table obtained for a single material to accommodate the tint variation in TFP is proposed for the use of different specimen materials. Discontinuities in fringe order variation are smoothed using the refined TFP (RTFP) procedure. The elegance of the new methodology for solving a multi-material system is bought out by solving the problem of a bi-material Brazilian disc. The results obtained are compared with the phase shifting technique.     

A class of constacyclic codes over a finite field-II

Let \(\mathbb{F}_q\) be a finite field with q = p ^m elements, where p is any prime and m ≥ 1. In this paper, we explicitly determine all the μ-constacyclic codes of length ? ⁿ over \(\mathbb{F}_q\), where ? is an odd prime coprime to p and the order of μ is a power of ?. All the repeated-root λ- constacyclic codes of length ? ⁿ p ^s over \(\mathbb{F}_q\) are also determined for any nonzero λ in \(\mathbb{F}_q\). As examples all the λ-constacyclic codes of length 3 ⁿ p ^s over \(\mathbb{F}_q\) for p = 5, 7, 11, 19 for n ≥ 1, s ≥ 1 are derived. We also obtain all the self-orthogonal negacyclic codes of length ? ⁿ over \(\mathbb{F}_q\) when q is odd prime power and give some illustrative examples.     

Synthesis and characterization of oxide cathode materials of the system (1-x-y)LiNiO<Subscript>2</Subscript>·xLi<Subscript>2</Subscript>MnO<Subscript>3</Subscript>·yLiCoO<Subscript>2</Subscript>

Composite cathode materials produced by integrating isostructural (2D-layered) compounds LiNiO₂, LiCoO₂, and Li₂MnO₃ (Li(Li_1/3Mn_2/3)O₂) have been investigated utilizing a compositional phase diagram. The samples were characterized by multiple techniques to establish structure–property relationships. Specifically, for structural characterization, powder X-ray diffraction, scanning electron microscopy, thermo-gravimetric analysis, and X-ray photoelectron spectroscopy were carried out. For properties, electrochemical characterization was carried out. The best composition showed a discharge capacity of 244 mAh/g (C/15 rate) in the testing range of 4.6–2 V, with good coulombic efficiency and cyclability.