<p>Shiv Nadar University is a comprehensive, multidisciplinary, research-focused, and student-centric University offering a full range of academic programs at the undergraduate, postgraduate and doctoral level. With state-of-the-art infrastructure, the University comprises of academic wings, sophisticated labs, international standard sports facilities, amphitheaters, auditorium, conference rooms and smart classrooms. The University&rsquo;s goal is to become internationally recognized for the quality of its research and creative endeavors and their applicability to improving quality of life, generating new insights and expanding the boundaries of human knowledge creativity. Committed to excellence in teaching, research and service, the University aims to serve the higher education needs of India and the world beyond.</p>

Shiv Nadar University

(SoNS) School of Natural Sciences

Chemistry

World University root node

Fulltext

Acta Crystallographica Section B: Structural Science

Erratum: Electron density study of 2H-chromene-2-thione (Acta Crystallographica Section B: Structural Science (2002) B58 (1011-1017))

A dendritic polyester based on pentaerythritol and 1,2,4 - benzenetricarboxylic acid anhydride followed by modification with glycidyl methacrylate was synthesised by using a divergent approach. The dendrimer (D-2) thus obtained had approximately eight double bonds. Several blends of D-2 with varying proportions of bismethacryloxy derivative of diglycidyl ether of bisphenol-A having styrene as a reactive diluent (VE resin) were prepared. The Brookfield viscosity of VE resin increased with an increase in D-2 content in the blends. Curing behaviour of these resins in the presence of AIBN was investigated by DSC. No significant change in curing exotherm was observed by addition of D-2 to the VE resin. Isothermal curing of resin samples in the presence of AIBN was done at 60 °C for 5 h and then at 150 °C for 90 mins. A significant improvement in char yield at 600 °C in nitrogen atmosphere was observed in samples containing D-2. Mechanical properties of glass fiber reinforced laminates with 31 ± 3% of resin content (w/w) were also determined. Smoke density of laminates increased with decrease in D-2 content in the resin, whereas only a marginal effect on limiting oxygen index was observed.

Materials Research Innovations

Thermal behaviour of dendritic methacrylated polyesters

We report a systematic search for electrical signature of defect clusters in ion-implanted silicon using Deep Level Transient Spectroscopy (DLTS) and related capacitance transient measurements. We show that slow carrier capture dynamics among energy broadened multiple states and occurrence of capture induced metastable states are some of the distinctive hall marks of cluster related trap levels. Isothermal transient spectroscopy is shown to be appropriate for recognition of these features.

Physics

Proceedings of SPIE - The International Society for Optical Engineering

Carrier dynamics at deep traps in ion implanted silicon: Possible signature of defect clusters

A technique is presented for the highthroughput screening of ion-exchange displacers. Potential displacers were employed to displace proteins in parallel batch ion-exchange experiments. The percentage of protein displaced from a particular stationary phase was then used as a parameter to rank the displacers. By employing this technique, a large number of molecules possessing a range of affinities and properties could be rapidly evaluated. This data was then used together with traditional and electron density-based transferable atom equivalent (TAE) molecular descriptors computed for the displacer molecules to produce quantitative structure-efficacy relationship (QSER) models using a genetic algorithm/partial least squares (GA/PLS) regression approach. The QSER models were generated using a portion of the protein-displacement data, with the remainder serving as a test set. Descriptor selection and model building was accomplished using a genetic algorithm/partial least squares approach. The resulting models were found to have high-correlation coefficients and could be used to accurately predict the behavior of molecules not included in the training set. In addition, the models were employed to examine a virtual library of displacers based on modifications of neomycin to provide further insight into displacer design. The results presented here indicate that it may be possible to design displacers that can dramatically improve the effective selectivity of ion-exchange chromatographic materials. © 2002 Wiley Periodicals, Inc.

Biotechnology and Bioengineering

High-throughput screening and quantitative structure-efficacy relationship models of potential displacer molecules for ion-exchange systems

In this paper, we present a systematic structural study on the (Al1-xGex)65Cu10+yMn25-y alloy system. The emphasis of the work is to understand the effect of Ge concentration on the occurrence, growth and morphology of the quasicrystalline phases in the system, as we move from Cu/Mn ratio of 20:15 to 10:25 in order to span the varied electronic behavior (as shown in the literature) of this quaternary system. Throughout the series, coexistence of icosahedral and decagonal phases has been observed. To the best of our knowledge, these are the first observations of their type in the alloy system (AlGe) CuMn. © 2002 Elsevier Science B.V. All rights reserved.

Materials Letters

Structural studies of (Al1-xGex)65Cu10+yMn25-y (0≤x≤0.4, 0≤y≤10)

In this paper, we report the formation of stable icosahedral Al-Cu-Fe quasicrystalline thin films by thermal vapor deposition techniques (indirect heating and e-beam heating) from a single source. Deposition of these films by a single-source indirect heating method, in the stable icosahedral phase, is reported for the first time. A direct comparison between the two different heating methods has been made. The final compositions of the prepared films with desired properties were found to be Al62.9Cu24.6Fe12.5 (indirect heating method) and Al63.1Cu24.5Fe12.4 (e-beam method), respectively. The resistivities of the films prepared by both methods were ∼2000 μΩ cm at room temperature and ∼ 4000 μΩ cm at 10 K. © 2002 Elsevier Science Ltd. All rigts reserved.

Materials Research Bulletin

Preparation of Al-Cu-Fe thin films by vapor deposition technique from a single source

The PT-symmetric square well problem is considered in a SUSY framework. When the coupling strength Z lies below the critical value Z 0 (c) where PT symmetry becomes spontaneously broken, we find a hierarchy of SUSY partner potentials, depicting an unbroken SUSY situation and reducing to the family of sec 2-like potentials in the Z → 0 limit. For Z above Z 0 (c), there is a rich diversity of SUSY hierarchies, including some with PT-symmetry breaking and some with partial PT-symmetry restoration.

Modern Physics Letters A

PT-symmetric square well and the associated SUSY hierarchies

This article focuses on the influence of chemical driving forces on the mixing and phase formation taking place at the interface of highly reactive metal/semiconductor systems under ion-beam irradiation. Ta/Si bilayers were irradiated with Ar, Kr, and Xe ions to fluences of (0.5-2.5) × 1016 ions/cm2 and at temperatures between liquid nitrogen and 400 °C. The interface mixing and silicide formation were monitored as function of the ion mass and fluence by means of Rutherford backscattering spectrometry and x-ray diffraction. The interface broadening variance was found to depend linearly on the ion fluence and was explained with the help of a compound formation model involving local or global thermal spikes. The results are compared with those found in other silicide and germanide systems. The transition from local to global spikes was found to occur at the critical deposited damage energy of about 2.5 keV/nm.

Physical Review B - Condensed Matter and Materials Physics

Atomic mixing and interface reactions in Ta/Si bilayers during noble-gas ion irradiation

Life Sciences

Current Science

Female sex-associated RAPD marker in pointed gourd (Trichosanthes dioica Roxb.)

Valence bonds are the basic entities in many chemical compounds. In a linear array of atoms translational invariance tells us the bonds have to be superposed. These superposed bond variables are shown to satisfy a closed algebra. We use a natural parameter in the algebra to truncate it. This allows us to transform the Hamiltonian of electrons into the Hamiltonian of bonds. Comparing the solutions, we establish the validity of the truncation procedure. The quantum bonds are obtained by superposing valence bonds with arbitrary phases. We demonstrate that these quantum valence bonds satisfy an extended algebra that admits truncation. The electron Hamiltonian is recast in terms of the quantum bonds and solved.