010991   Gomathi G;Gopalakrishnan R (Crystal Research Lab, Physics Dep, Anna Univ, Chennai-600 025, Email: krgkrishnan@yahoo.com) : Physicochemical, electrical and optical study of methyl-3(2-furylmethylidene) carbazate single crystal. Bull Mater Sci 2015, 38(5), 1411-17.

The current study provides an insight into the physicochemical properties of an organic single crystal methyl-3-(2-furylmethylidene) carbazate, which was grown by employing the slow evaporation solution growth technique and its results were correlated for application point of view. The grown crystal was confirmed by performing single-crystal X-ray diffraction studies and Fourier transform infrared analysis. The optical, thermal, dielectric and mechanical properties of the grown single crystal were primarily investigated. Etching study was performed to analyse the defects and growth mechanism. Kurtz-Perry powder technique was used to study the second harmonic generation efficiency of the crystal and the crystal was found to exhibit Type-I phase matching.

8 illus, 3 tables, 26 ref

010990   Dudhe C M;Arjunwadkar P R (Physics Dep, Government Institute of Science, Nagpur-400 001, Email: chandraguptadudhe@gmail.com) : Nucleation and evaporation of domains due to electric fields at room temperature in BaTiO₃B< single crystals. Bull Mater Sci 2015, 38(5), 1423-7.

A study of nucleation and evaporation of 90° and 180° domains by external direct current (dc) electric field at room temperature in barium titanate single crystals has been carried out using reflecting microscope. It was observed that both the 90° and 180° domains were nucleated at some sites, while evaporated at some other sites of the crystal surface. The 90° domain follows the mechanism of micro-domain wall nucleation as well as the evaporation based on impurity dipoles, like reported for KNbO₃. The mechanism of the 180° domain nucleation is not established yet. However, in both cases, nucleation and evaporation are operative simultaneously by the same electric field, which seems to be quite interesting and which can be attributed to the different critical lengths of the domains.

7 illus, 23 ref

010989   Dey B (Physics Dep, Savitribai Phule Pune Univ, Pune-411 007, Email: bdey@physics.unipune.ac.in) : Excitations and management of the nonlinear localized gap modes. Pramana J Phys 2015, 85(5), 961-74.

Authors discuss about the theory of nonlinear localized excitations, such as soliton and compactons in the gap of the linear spectrum of the nonlinear systems. We show how the gap originates in the linear spectrum using examples of a few systems, such as nonlinear lattices, Bose-Einstein condensates in optical lattice and systems represented by coupled nonlinear evolution equations. We then analytically show the excitation of solitons and compacton-like solutions in the gap of the linear spectrum of a system of coupled Korteweg-de Vries (KdV) equations with linear and nonlinear dispersions. Finally, we discuss about the theory of Feshbach resonance management and dispersion management of the soliton solutions.

6 illus, 41 ref

010988   Deepika;Dhar R;Singh S;Atul Kumar (Applied Physics Dep, Guru Jambheshwar Univ of Science and Technology, Hisar-125 001, Email: rakesh285@gmail.com) : Effect of capping agents on optical and antibacterial properties of cadmium selenide quantum dots. Bull Mater Sci 2015, 38(5), 1247-52.

Cadmium selenide quantum dots (CdSe QDs) were synthesized in aqueous phase by the freezing temperature injection technique using different capping agents (viz. thioglycolic acid, 1-thioglycerol, L-cysteine). Absorption spectra of CdSe QDs exhibited a blue shift as compared to its bulk counterpart, which is an indication of quantum confinement effect. The photoluminescence spectra of CdSe QDs confirmed that the particles are poly-dispersed and possess enhanced luminescent property, depending upon the chemical nature of capping agents. The QDs have been characterized by Fourier-transform infrared spectroscopy, atomic absorption spectroscopy and transmission electron microscopy. Further, antimicrobial activity of as-prepared QDs has also been investigated using the disk diffusion method.

5 illus, 2 table, 24 ref

010987   Buono P L;Chan B;Palacios A;In V (Faculty of Science, Univ of Ontario Institute of Technology, 2000 Simcoe Sst N, Oshawa, ON L1H 7K4, Canada, Email: palacios@euler.sdsu.edu) : Hamiltonian approach to model and analyse networks of nonlinear oscillators: applications to gyroscopes and energy harvesters. Pramana J Phys 2015, 85(5), 929-45.

Over the past twelve years, ideas and methods from nonlinear dynamics system theory, in particular, group theoretical methods in bifurcation theory, have been used to study, design, and fabricate novel engineering technologies. For instance, the existence and stability of heteroclinic cycles in coupled bistable systems has been exploited to develop and deploy highly sensitive, lowpower, magnetic and electric field sensors. Also, patterns of behaviour in networks of oscillators with certain symmetry groups have been extensively studied and the results have been applied to conceptualize a multifrequency up/down converter, a channelizer to lock into incoming signals, and a microwave signal generator at the nanoscale. In this manuscript, a review of the most recent work on modelling and analysis of two seemingly different systems, an array of gyroscopes and an array of energy harvesters, is presented. Empirical values of operational parameters suggest that damping and external forcing occur at a lower scale compared to other parameters, so that the individual units can be treated as Hamiltonian systems. Casting the governing equations in Hamiltonian form leads to a common approach to study both arrays. More importantly, the approach yields analytical expressions for the onset of bifurcations to synchronized oscillations. The expressions are valid for arrays of any size and the ensuing synchronized oscillations are critical to enhance performance.

5 illus, 29 ref

010986   Balakrishnan R;Satija I I (NO, The Institute of Mathematical Sciences, C.I.T. Campus, Chennai-600 113, Email: radha@imsc.res.in) : Solitons in a hard-core bosonic system: gross-pitaevskii type and beyond. Pramana J Phys 2015, 85(5), 1033-55.

Authors present a unified formulation to investigate solitons for all background densities in the Bose-Einstein condensate of a system of hard-core bosons with nearest-neighbour attractive interactions, using an extended Bose-Hubbard lattice model. We derive in detail the characteristics of the solitons supported in the continuum version, for the various cases possible. In general, two species of solitons appear: A nonpersistent (NP) type that fully delocalizes at its maximum speed and a persistent (P) type that survives even at its maximum speed. When the background condensate density is nonzero, both species coexist, the soliton is associated with a constant intrinsic frequency, and its maximum speed is the speed of sound. In contrast, when the background condensate density is zero, the system has neither a fixed frequency, nor a speed of sound. Here, the maximum soliton speed depends on the frequency, which can be tuned to lead to a cross-over between the NP-type and the P-type at a certain critical frequency, determined by the energy parameters of the system. We provide a single functional form for the soliton profile, from which diverse characteristics for various background densities can be obtained. Using mapping to spin systems enables us to characterize, in a unified fashion, the corresponding class of magnetic solitons in Heisenberg spin chains with different types of anisotropy.

4 illus, 28 ref

010985   Bakkyaraj T;Sahadevan R (Ramanujan Institute for Advanced Study in Mathematics, Madras Univ, Chepauk, Chennai-600 005, Email: ramajayamsaha@yahoo.co.in) : Group formalism of lie transformations to time-fractional partial differential equations. Pramana J Phys 2015, 85(5), 849-60.

Systematic method is given to derive Lie point symmetries of time-fractional partial differential equation with Riemann-Liouville fractional derivative and its applicability illustrated through (i) time-fractional diffusive equation and (ii) time-fractional cylindrical Korteweg-de Vries equation. Using the Lie point symmetries obtained, we show that each of them has been transformed into ordinary differential equation of fractional order with a new independent variable. We also explain how exact or invariant solutions can be derived from the obtained point symmetries.

24 ref

010984   Arun R;Sabareesan P;Daniel M (Centre for Nonlinear Dynamics, School of Physics, Bharathidasan Univ, Tiruchirapalli-620 024) : Impact of current on static and kinetic depinning fields of domain wall in ferromagnetic nanostrip. Pramana J Phys 2015, 85(5), 947-59.

Impact of current on static and kinetic depinning fields of a domain wall in a onedimensional ferromagnetic nanostrip is investigated analytically and numerically by solving the Landau-Lifshitz-Gilbert equation with adiabatic and non-adiabatic spin-transfer torques. The results show that in the absence of current, the static depinning field is greater than the kinetic depinning field. Both the depinning fields decrease by increasing the current applied in a direction opposite to the direction of the applied field. Both the depinning fields can also be tuned by the current to make them equal.

4 illus, 28 ref

010983   Akyol M;Ayas A O;Akca G;Cetin S K;Kicibil A (Physics Dep, Faculty of Science and Letters, Cukurova Univ, 01330, Adana, Turkey, Email: ahmetcan@cu.edu.tr) : Effect of Ca doping on thermally activated flux in the Y₃Ba₅Cu₈O₁₈ superconductor. Bull Mater Sci 2015, 38(5), 1231-7.

Y₃Ba₅Cu₈O₁₈ (Y-358) and Y₃Ba₅Ca₂Cu₈O₁₈ (YCa-358) compounds were prepared by the so-called sol-gel method. The effect of doping Ca atoms into the Y₃Ba₅Cu₈O₁₈ superconductor is studied by employing the electrical resistivity measurements at various magnetic fields. The possible degradation in microstructural and superconducting properties due to the addition of Ca was discussed. The resistivity as a function of temperature measurements shows that the depression in superconducting temperature is more pronounced for both samples. A systematic analysis of the magnetoresistivity of the Y-358 and YCa-358 compounds has been carried out by using the thermally activated flux flow (TAFF) model. The TAFF activation energy, U, is field dependent and obeys the power law U = cH^{α, where α increases while c decreases with the addition of Ca. Furthermore, U and the calculated upper critical field, H_c2, decrease with the addition of Ca.}

7 illis, 2 table, 25 ref

010982   Abhinav Kumar;Vyas V M;Panigrahi P K (NO, Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur-741 246, Email: pprasanta@iiserkol.ac.in) : Solitons and spin transport in graphene boundary. Pramana J Phys 2015, 85(5), 1023-32.

It is shown that in (2+1)-dimensional condensed matter systems, induced gravitational Chern-Simons (CS) action can play a crucial role for coherent spin transport in a finite geometry, provided zero-curvature condition is satisfied on the boundary. The role of the resultant KdV solitons is explicated. The fact that KdV solitons can pass through each other without interference, represent `resistanceless' spin transport.

51 ref

008958   Viswanatha R (International Centre for Materials Science and New Chemistry Unit, Jawaharlal Nehru Centre for Advanced Materials Research, Jakkur, Bangalore-560 064, Email: rv@jncasr.ac.in) : Effect of transition metal dopants on the optical and magnetic properties of semiconductor nanocrystals. Pramana J Phys 2015, 84(6), 1055-64.

This review discusses the recent developments in doped semiconductor nanocrystals with a special emphasis on the effect of dopant on the electronic structure of the host nanocrystals. The review focusses on 3d transition metal dopants with unique electronic structure making them receptive for dramatic changes in magnetism, absorption and photoluminescence properties by the successful introduction of a small percentage of dopants into the nanocrystals. Many of these properties are shown to be qualitatively different from that of the bulk properties, leading to challenges in understanding the nature and effects of the confinement of the host. The optical and magnetic changes induced by Mn doping is first reviewed, followed by the use of Cu as a probe to understand the bulk and surface electronic structure of the host. The review concludes with a short section on photomagnetism induced by Cu on the host nanocrystal and a summary of the work with other transition metal ions.

5 illus, 69 ref

008957   Topwal D (NO, Institute of Physics, Sachivalaya Marg, Sainik School P.O., Bhubaneswar-751 005, Email: dinesh.topwal@iopb.res.in) : Quantum cofinement effects in low-dimensional systems. Pramana J Phys 2015, 84(6), 1023-32.

The confinement effects of electrons in ultrathin films and nanowires grown on metallic and semiconducting substrates investigated using band mapping of their electronic structures using angle-resolved photoemission spectroscopy is discussed here. It has been shown that finite electron reflectivity at the interface is sufficient to sustain the formation of quantum well states and weak quantum well resonance states even in closely matched metals. The expected parabolic dispersion of sp-derived quantum well states for free-standing layers undergoes deviations from parabolic behaviour and modifications due to the underlying substrate bands, suggesting the effects of strong hybridization between the quantum well states and the substrate bands. Electron confinement effects in low dimensions as observed from the dispersionless features in the band structures are also discussed.

7 illus, 25 ref

008956   Tandon B;Aswathi A;Nag A (Chemistry Dep, Indian Institute of Science Education and Research (IISER), Pune-411 008, Email: angshuman@iiserpune.ac.in) : Colloidal transparent conducting oxide nanocrystals: a new infrared plasmonic material. Pramana J Phys 2015, 84(6), 1087-98.

Thin films of transparent conducting oxides (TCO) are technologically important for applications as a visible light transparent electrode in a wide variety of optoelectronic devices. In the last few years, researchers started to explore novel size- and shape-dependent properties of TCO, where the crystallite size is <126>10 nm. So far, the localized surface plasmon resonance (LSPR) properties of TCO nanocrystals (NCs) have been found to be the most interesting. TCOs like Sn-doped In2O3, Al-doped ZnO and In-doped CdO NCs, exhibit LSPR band in near- to mid-infrared region. LSPR from a TCO NC exhibits many intrinsic differences with that of a metal NC. Carrier density in a TCO NC can easily be tuned by controlling the dopant concentration, which allows the LSPR band to be tuned over a range of <126>2000 nm (<126>0.62 eV) in the near- to mid-infrared region. This review discusses recent advances in the understanding of plasmonic properties of various TCO NCs and highlights the potential applications of such unique plasmonic properties.

5 illus, 44 ref

008955   Swarnkar H;Arora G (Physics Dep, Paher Univ, Udaipur-313 003, Email: garora.gits@gmail.com) : Characterization of electronic properties of potassium chalcogenides using first principles method. Int J chem Sci 2015, 13(1), 107-14.

In this paper, we report the electronic properties of potassium chalcogenides K₂X (X = S and Se) using various DFT schemes within the frame work of linear combination of atomic orbitals approach. These compounds show indirect band gap with conduction band minima at G point and valence band maxima at X and L point for K₂S and K₂Se, respectively. The relative nature of bonding in these chalcogenides is explained in terms of Mulliken's population analysis, which shows that the amount of charge transfer from K to chalcogen atom increases as we move from S → Se, so the ionicity increases or covalency decreases from K₂S → K₂Se.

3 illus, 3 tables, 35 ref

008954   Sharma A K;Sharma A K;Sharma V;Kumar Rakesh; Chauhan S S;Singh O P (Physics Dep, Maharishi Markandeshwar Univ, Mulllana, Ambala-133 207, Email: anil67042@gmail.com) : Dft studies of vibrational + requencies of aspirin, paractamol and phenacetin. Int J chem Sci 2015, 13(1), 123-32.

Density functional theory DFT (B3LYP)/6-31G (d) has been applied to compute the geometry optimization, dipole moment and vibrational frequencies of aspirin, paracetamol and phenacetin. From the comparison of vibrational frequencies, it is observed that the value of O-H stretching in aspirin is lower as compared to paracetamol shows its greater tendency to form cation whereas paracetamol has least tendency to form cation as the O-H stretching in paracetamol is at greater frequency even than that of phenacetin, which explains that why there is displacement of -COOH by -OH group in aspirin i.e. (aspirin) acetyl-salicylic acid readily converts into salicylic acid, which is responsible for most of its actions. The greater values of O-H and C-H stretching of paracetamol than aspirin and phenacetin explains its selective behavior to inhibit cyclooxynase-2 (COX-2) and poor inhibitor of the synthesis of prostaglandins, which is responsible for pain headache and infection. On comparison of dipole moment of it is also observed that the order is Aspirin <62> Paracetamol <62> Phenacetin and from our earlier ADMP studies of total energy curve vs time in trajectory curve of aspirin, paracetamol and pehnacetin at DFT/6-31G(d) it is found that the energy required to release Hydrogen from these drugs are in the order Paracetamol <62> Phenacetin <62> Aspirin, therefore from infrared spectra, dipole moment and ADMP studies of aspirin, paracetamol and phenacetin it is concluded that aspirin is most reactive which explains that why it inhibit the synthesis of prostaglandins responsible for pain, headache and fever; restricts the blood supply to the tumor in effectnot allowing it to grow than a pea and paracetamol is a poor inhibitor of prostaglandins synthesis, does not have antiinflammatory action; phenacetin shows more reactive sites than paracetamol but less than aspirin, which give the evidence that why it is being replaced aspirin.

7 illus, 1 table, 30 ref

008953   Sarita;Rakesh Kumar;Sigh G;Singh B P (Physics Dep, CCS Univ, Meerut-250 002, Email: mrssaritasaroha@rediffmail.com) : Tailoring of band garp in vacuum evaporated Cd_1-xZn_xSe thin films. Ann Agri Bio Res 2015, 20(1), 95-8.

Ternary system of Cd, Zn and Se provided a possibility of tailoring their physical properties as per device fabrication requirements and proved themselves as an important semi-conducting system for future advancement in the field of device fabrication. Thin films of Cd_1-x Zn_x Se with variable composition (0≤x≤) were deposited on to highly clean glass substrates by vacuum evaporation technique. The optical characterization of as-deposited films had been done by using Hitachi Spectrophotometer model U-3400 at room temperature. The energy band gap of these films was determined with the help of absorption spectra by using well known Tauc relation. The absorption edge shifted towards lower wave length range as x (composition) increased from x = 0 (CdSe) to x =1 (ZnSe). The variations of energy band gap had been determined and discussed.

4 illus, 20 ref

008952   Sarita;Gulbir Singh (Physics Dep, CCS Univ, Meerut-250 002, Email: mrssaritasaroha@rediffmail.com) : Cd_1-xZn_xse semi-conducting thin films of groups II-VI. Ann Agri Bio Res 2015, 20(1), 88-94.

Thin film science and technology plays an important role in the high tech industries. In this regard, physics and technology of thin films play an important role to achieve this goal. Optical, structural and electrical properties are very important to understand the behaviour and performance of films in device fabrication. Ternary alloys of II-VI group semi-conductors provide a possibility of tailoring their properties as per requirements and hence project themselves as important semiconducting materials for future advancement in the field of device fabrication. The characters of thin films vary in comparison to the bulk of same material. An introduction to CdSe and ZnSe is given in this review. Also the importance, applications and preferation of thin films over tfieir bulky parts and work done by many scientists on thin films have been discussed.

^iia2 illus, 1 table, 29 ref

008951   Paul S;Raj S (Physical Sciences Dep, Indian Institute of Science Education and Research-Kolkata, Mohanpur Campus, Nadia-741 246, Email: raj@iiserkol.ac.in) : Understanding metal-insulator transition in sodium tungsten bronze. Pramana J Phys 2015, 84(6), 957-66.

Authors have carried out angle-resolved photoemission spectroscopy (ARPES) and spectro-microscopy studies to understand the metal-insulator transition (MIT) observed in sodium tungsten bronzes, Na_xWO₃. The experimentally determined band structure is compared with the theoretical calculation based on full-potential linear augmented plane-wave method. It has been found that there is a good gross agreement between experiment and theory. ARPES spectra on the insulating sample show that the states near E_F are localized due to the random distribution of Na in WO₃ lattice which causes strong disorder in the system. Our spectromicroscopy measurements on both insulating and metallic samples do not approve percolation model to explain MIT in Na_xWO₃. Photoemission spectroscopy on metallic samples does not show any Na-induced impurity band (level), which was one of the models to explain MIT. Electron-like Fermi surface(s) has been found from our experiment for metallic samples at the Γ(X) point which shows good agreement with band calculation.

7 illus, 21 ref

008950   Nirmala R;Morozkin A V;Malik S K (Physics Dep, Indian Institute of Technology Madras, Chennai-600 036, Email: nirmala@iitm.ac.in) : Magnetocaloric effect in rare-earth intermetallics: recent trends. Pramana J Phys 2015, 84(6), 977-85.

Magnetocaloric effect (MCE) is the change in isothermal magnetic entropy (ΔS_m) and adiabatic temperature (ΔT_ad) that accompany magnetic transitions in materials during the application or the removal of magnetic field under adiabatic conditions. The physics of MCE gets enriched by correlated spin-lattice degrees of freedom. This phenomenon has been actively investigated over the past few decades as it holds a promise for an alternate method of refrigeration/heat pumping. This has already resulted in several reviews on this topic. This paper focusses on some recent trends in this field and prospects of using rare-earth-based materials as active magnetic refrigerants over a broad temperature range that includes gas liquefaction and near-room temperature refrigeration/heating.

3 illus, 2 tables, 47 ref

008949   Nag A;Ray S (Materials Science Dep, Indian Association for the Cultivation of Science, Jadavpur, Kolkata-700 032, Email: mssr@iacs.res.in) : Magnetoresistance stories of double perovskites. Pramana J Phys 2015, 84(6), 967-75.

Tunnelling magnetoresistance (TMR) in polycrystalline double perovskites has been an important research topic for more than a decade now, where the nature of the insulating tunnel barrier is the core issue of debate. Other than the nonmagnetic grain boundaries as conventional tunnel barriers, intragrain magnetic antiphase boundaries (APB) as well as magnetically frustrated grain surfaces have also been proposed to act as tunnel barriers in Sr₂FeMoO₆. In this review, the present state of the debate has been discussed briefly and how the physical state of the material can affect the magnetoresistance signal of double perovskites in many different ways has been pointed out.

4 illus, 65 ref

008948   Mittal M;Sapra S (Chemistry Dep, Indian Institute of Technology Delhi, Hauz Khas, New Delhi-110 016, Email: sapra@chemistry.iitd.ac.in) : Narrowing the size distribution of CdTe nanocrystals using digestive ripening. Pramana J Phys 2015, 84(6), 1049-54.

Digestive ripening of polydispersed colloidal CdTe nanocrystals is performed which results in monodispersed nanocrystals (NCs) as studied by optical spectroscopy. Optimization of ligand and refluxing time is carried out. Monodispersed NCs are obtained using mercaptopropionic acid (MPA) as a digestive ripening agent at a refluxing time of 1-2 h. Digestive ripening of CdTe NCs, which are less polydispersed, is also executed and it leads to more monodispersed NCs. In all the cases, there is a shift of maximum emission wavelength of CdTe NCs after digestive ripening that may be due to Ostwald ripening along with digestive ripening.

4 illus, 3 tables, 23 ref

008947   Manju U (NO, CSIR-Institute of Minerals and Materials Technology, Sachivalaya Marg, Bhubaneswar-751 003, Email: manju@immt.res.in) : Correlation effects driven by reduced dimensionality in magnetic surface alloys. Pramana J Phys 2015, 84(6), 999-1009.

The evolution of electronic properties and correlation effects in manganese-based two-dimensional magnetic surface alloys are discussed. Enhanced correlations resulting from the reduced dimensionality of the surface alloys lead to the modification of the core level and valence band electronic structures resulting in the appearance of distinct satellite features. Apart from this, surface alloying-induced strong modifications in the substrate surface states arising from charge reorganization and electron transfer to the surface states as well as band-gap openings are also discussed.

6 illus, 36 ref

008946   Maiti K (Condensed Matter Physics and Materials Science Dep, Tata Institute of Fundamental Research, Homi Bhabha Road, Colaba, Mumbai-400 005, Email: kbmaiti@tifr.res.in) : Electronic structure of Fe-based superconductors. Pramana J Phys 2015, 84(6), 947-56.

Fe-based superconductors have drawn much attention during the last decade due to the presence of superconductivity in materials containing the magnetic element, Fe, and the coexistence of superconductivity and magnetism. Extensive study of the electronic structure of these systems suggested the dominant role of d states in their electronic properties, which is significantly different from the cuprate superconductors. In this article, some of our studies of the electronic structure of these fascinating systems employing high-resolution photoemission spectroscopy is reviewed. The combined effect of electron correlation and covalency reveals an interesting scenario in their electronic structure. The contribution of ligand p states at the Fermi level is found to be much more significant than indicated in earlier studies. Temperature evolution of the energy bands reveals the signature of transition akin to Lifshitz transition in these systems.

5 illus, 39 ref

008945   Mahatha S K;Menon K S R (Surface Physics and Material Science Div, Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata-700 064, Email: krishna.menon@saha.ac.in) : Growth and photoemission spectroscopic studies of ultrathin noble metal films on graphite. Pramana J Phys 2015, 84(6), 1011-22.

Growth of Cu, Ag and Au thin films on graphite(0 0 0 l)surface and possible formation of quantum well (QW) states originating due to the confinement of thin film sp electrons within the band gap of graphite along FM symmetry direction are investigated using low-energy electron diffraction (LEED) and angle-resolved photoemission spectroscopy (ARPES). Higher surface dif-fusivity and surface energy of Cu on graphite surface led to cluster growth and does not reveal any quantum size effect, while Ag and Au films grow epitaxially in spite of large lattice mismatch. However, better surface ordering has been achieved by growing Ag and Au at low temperature (LT), followed by room-temperature (RT) annealing which are evident from LEED and the presence of sharp Shockley-type surface state (SS) at Fermi level (E_F). ARPES study of Ag films on graphite does not show any QW states, whereas Au films demonstrate a very sharp SS, Au bulk bands and well-resolved QW states or resonances. The observed low in-plane dispersions of these Au QW states or resonances are compared with the dispersions obtained in the previous Au QW state studies as well as for free-standing Au films.

5 illus, 1 table, 44 ref

008944   Joshi A;Datar S (Applied Physics Dep, Defence Institute of Advanced Technology (DU), Girinagar, Pune-411 025, Email: suwarna.datar@gmail.com) : Carbon nanostructure composite for electromagnetic interference shielding. Pramana J Phys 2015, 84(6), 1099-16.

This communication reviews current developments in carbon nanostructure-based composite materials for electromagnetic interference (EMI) shielding. With more and more electronic gadgets being used at different frequencies, there is a need for shielding them from one another to avoid interference. Conventionally, metal-based shielding materials have been used. But due to the requirement of light weight, corrosion resistive materials, lot of work is being done on composite materials. In this research the forerunner is the nanocarbon-based composite material whose different forms add different characteristics to the composite. The article focusses on composites based on graphene, graphene oxide, carbon nanotubes, and several other novel forms of carbon.

3 illus, 135 ref

008943   Gerard C;Pizzagalli L (NO, Institut Pprime-CNSRS UPR3346, Universite de Poitiers-CNRS-ISAE-ENSMA, F86961 Chasseneuil Futuroscope Cedex, France, Email: celine.gerard@cnrs.pprime.fr ) : Mechanical behaviour of nanoparticles: elasticity and plastic deformation mechanisms. Pramana J Phys 2015, 84(6), 1041-8.

Nano-objects often exhibit drastically different properties compared to their bulk counterpart, opening avenues for new applications in many fields, such as in advanced composite materials, nanomanufacturing, nanoelectromechanical systems etc. As such, related research topics have become increasingly prominent in recent years. In this review on the mechanical behaviour of nanoparticles, the main investigation approaches are first briefly presented. The main results in terms of elasticity and plastic deformation mechanisms are then reported and discussed.

2 illus, 62 ref

008942   Das R;Mahadevan P (Condensed Matter Physics and Material Science Dep, S.N. Bose National Centre for Basic Sciences, Kolkata-700 098, Email: priya@bose.res.in) : Model for the direct-to-indirect band-gap transition in monolayer MoSe₂ under strain. Pramana J Phys 2015, 84(6), 1033-40.

A monolayer of MoSe2 is found to be a direct band-gap semiconductor. We show, within ab-initio electronic structure calculations, that a modest biaxial tensile strain of 3% can drive it into an indirect band-gap semiconductor with the valence band maximum (VBM) shifting from K point to Γ point. An analysis of the charge density reveals that while Mo-Mo interactions contribute to the VBM at 0% strain, Mo-Se interactions contribute to the highest occupied band at Γ point. A scaling of the hopping interaction strengths within an appropriate tight binding model can capture the transition.

7 illus, 2 tables, 17 ref

008941   Choudhury D (Physics Dep, Indian Institute of Technology, Kharagpur-721 302, Email: debraj@phy.iitkgp.ernet.in) : Site-specific doping, tunable dielectric properties and intrinsic paramagnetism in Mn-doped SrTiO₃. Pramana J Phys 2015, 84(6), 987-97.

Mn doping in SrTiO₃ leads to the emergence of qualitatively distinct and novel physical properties. We show that Mn ions can be controllably doped at either of the perovskite A (Sr) or B (Ti) site as well as at both sites simultaneously and the resultant physical properties depend intimately on the particular dopant site. We critically review the recent literature on various Mn-doped SrTiO3 systems, which includes reports of dielectric glass, spin-glass and ferromagnetism and by combining experiments with first-principles calculations, we demonstrate that depending on the particular dopant site for Mn ions, the dielectric properties can be widely tuned from a quantum paraelectric to a dielectric glass. However, the intrinsic magnetism in all these cases remains essentially paramagnetic for phase-pure systems.

7 illus, 1 table, 37 ref

008028   Wang F (Physics Dep, Purdue Univ, West Lafayette, Indiana 47907 USA, Email: fqwang@purdue.edu) : Jet-quenching and correlations. Pramana J Phys 2015, 84(5), 801-19.

This article reviews recent advances in our understanding of the experimental aspects of jet-quenching and correlations in relativistic heavy-ion collisions at RHIC and LHC. Emphasis is put on correlation measurements, namely jet-like correlations with anisotropic flow subtraction in heavy-ion collisions and long-range pseudorapidity correlations in small systems. Future path on correlation studies is envisioned which may elucidate jet-medium interactions and the properties of the hot dense medium in QCD.

4 illus, 152 ref

008027   Vardaci E;Nitto A D;Nadtochy P N;Brondi A; Rana G L;Moro R;Cinausero M;Prete G;Gelli N;Kozulin E M;Knyazheva G N;Itkis I M (Di Fisica Dep, Univ Di Napoli, "Federico II" and INFN, Complesso Univ, Monte Sant Angelo, Via Cintia, Edificio 6-801 26, Email: vaardaci@na.infn.it) : Fission dynamics with systems of intermediate fissility. Pramana J Phys 2015, 85(2), 345-55.

A 4π light charged particle spectrometer, called 8πLP, is in operation at the Laboratori Nazionali di Legnaro, Italy, for studying reaction mechanisms in low-energy heavy-ion reactions. Besides about 300 telescopes to detect light charged particles, the spectrometer is also equipped with an anular PPAC system to detect evaporation residues and a two-arm time-of-flight spectrometer to detect fission fragments. The spectrometer has been used in several fission dynamics studies using as a probe light charged particles in the fission and evaporation residues (ER) channels. This paper proposes a journey within some open questions about the fission dynamics and a review of the main results concerning nuclear dissipation and fission time-scale obtained from several of these studies. In particular, the advantages of using systems of intermediate fissility will be discussed.

3 illus, 2 table, 33 ref

008026   Tripathi R;Sodaye S;Sudarshan K (Radiochemistry Div, Bhabha Atomic Research Centre, Mumbai-400 085, Email: rahhult@barc.gov.in) : Non compound nucleus fission in actinide and pre-actinide regions. Pramana J Phys 2015, 85(2), 315-22.

In this article, some of our recent results on fission fragment/product angular distributions are discussed in the context of non-compound nucleus fission. Measurement of fission fragment angular distribution in ^{28Si+176 Yb reaction did not show a large contribution from the non-compound nucleus fission. Data on the evaporation residue cross-sections, in addition to those on mass and angular distributions, are necessary for better understanding of the contribution from non-compound nucleus fission in the pre-actinide region. Measurement of mass-resolved angular distribution of fission products in 20Ne+232Th reaction showed an increase in angular anisotropy with decreasing asymmetry of mass division. This observation can be explained based on the contribution from pre-equilibrium fission. Results of these studies showed that the mass dependence of anisotropy may possibly be used to distinguish pre-equilibrium fission and quasifission.}

3 illus, 29 ref

008025   Thomas R G (Nuclear Phy Div, Bhabha Atomic Research Centre, Trombay, Mumbai-303 13, Email: rgthomas@barc.gov.in) : Fission fragmet mass and angular distributions: probes to study non-equilibrium fission. Pramana J Phys 2015, 85(2), 303-13.

Synthesis of heavy and superheavy elements is severely hindered by fission and fission-like processes. The probability of these fission-like, non-equilibrium processes strongly depends on the entrance channel parameters. This article attempts to summarize the recent experimental findings and classify the signatures of these non-equilibrium processes based on macroscopic variables. The importance of the sticking time of the dinuclear complex with respect to the equilibration times of various degrees of freedom is emphasized.

9 illus, 34 ref

008024   Strickland M (Physics Dep, Kent State Univ, Kent, OH 44242, USA, Email: mstrick6@kent.edu) : Thermalization and isotropization in heavy-ion collisions. Pramana J Phys 2015, 84(5), 671-84.

The current understanding of the processes driving the thermalization and isotropiza-tion of the quark gluon plasma (QGP) created in ultrarelativistic heavy-ion collisions (URHICs) is reviewed. Initially, the phenomenological evidence in favour of the creation of a thermal but momentum-space anisotropic QGP in URHICs is discussed. Further, the degree of isotropiza-tion using viscous (dissipative) hydrodynamics, weak-coupling approaches to QGP dynamics, and strong-coupling approaches to QGP dynamics are discussed. Finally, recent progress in the area of real-time non-Abelian gauge field simulations and non-Abelian Boltzmann-Vlasov-based hard-loop simulations are reported.

4 illus, 140 ref

008023   Song H (Physics and State Key Laboratory of Nuclear Physics and Technology Dep, Peking Univ, Beijing-100 871, Email: huichaosong@pku.edu.cn) : Hydrodynamic modelling for relativistic heavy ion collisions at RHIC and LHC. Pramana J Phys 2015, 84(5), 703-15.

In this article, we briefly review recent progress on hydrodynamic modelling and its implementations to relativistic heavy-ion collisions at RHIC and LHC. The related topics include: (1) initial-state fluctuations, final-state correlations and event-by-event hydrodynamics, (2) extracting the QGP shear viscosity from flow data, (3) flow and hydrodynamics in p+Pb collisions at √SNN = 5.02 TeV.

1 illus, 110 ref

008022   Singh S;Rajesh Kumar;Singh J;Singh R (Environmental Science Dep, School of Basic Sciences and Research, Sharda Univ, Greater Noida-201 306, Email: rajesh.kumar@shara.ac.in) : Clean development mechanism to reduce green house gases. Invertis J renewable Energy 2015, 5(2), 95-104.

Keeping the issue of global warming in mind, renewable energy is vital as this has an attractive attribute that the fuel is free from emission. The market based mechanisms like Clean Development Mechanism (CDM) is a process which assist the development of renewable energy. The objective of this paper is to describe the pros and cons of this mechanism which support the renewable energy projects and make them attractive in terms of investment.

2 illus, 1 table, 35 ref

008021   Singh K P;Yogesh Kumar (NO, , Mechanical Engineering DCTM Dep, Palwal, Haryana, Email: kishan_amu@rediffmail.com) : Experimental study of a single slope solar still. Invertis J renewable Energy 2015, 5(2), 78-83.

Performance analysis of a single slope basin type solar still has been carried out based on the experimental data recorded at Aligarh for some typical days. The radiative, convective and evaporative heat transfer coefficients between the water surface and the glass cover through the humid air are evaluated using standard correlations and those used by other authors. The experimental data include the temperatures of basin liner (absorber plate), water mass, humid air, glass cover surface and the ambient air.

7 illus, 14 ref

008020   Sheena P A;Priyanka K P;Aloysiussabu N;Ganesh S;Varghese T (MES Asmabi College, P Vemballur, Kerala-680 671, Email: nanoncm@gmail.com) : Effect of electron beam irradiation on the structure and optical properties of nickel oxide nanocubes. Bull Mater Sci 2015, 38(4), 825-30.

This work reports the effect of electron beam (EB) irradiation on the structure and optical properties of nanocrystalline nickel oxide (NiO) cubes. NiO nanocubes were synthesized by the chemical precipitation method. The characterization was carried out by employing analytical techniques like X-ray diffraction, transmission electron microscopy, UV-visible and photoluminescence (PL) spectroscopy. The present investigation found that non-stoichiometry, defects and particle size variation caused by EB irradiation have a great influence on optical band gap, blue shift and band modification of absorption and PL spectra. Moreover, EB irradiation can result enhanced optical absorption performance and photo-activity in NiO nanocubes for optoelectronics and photo-catalytic applications. The study of International Commission on Illumination chromaticity diagram indicates that NiO can be developed as a suitable phosphor material for the application in near ultraviolet excited colour LEDs

7 illus, 2 table, 28 ref

008019   Schroder W U (Chemistry and Physics Dep, Rochester Univ, Rochester, NY 14627, USA, Email: schroeder@chem.rochester.edu) : New prompt heavy-ion induced fission mode. Pramana J Phys 2015, 85(2), 227-38.

Fission instabilities induced by mechanical and thermal stresses on intermediate nuclear systems in heavy-ion reactions are poorly understood but should reveal independent evidence for the nuclear equation of state (EoS), notably the tensile strength of finite nuclei. Experimental evidence is presented in support of a new mode of prompt fission of the composite nucleus formed in central ^{78Kr+40Ca collisions at only a few MeV per nucleon above the interaction barrier. The new process recalls the 'L-window for fusion' phenomenon, which was predicted by the early reaction theory and reappears in modern DFT model calculations.}

9 illus, 56 ref

008018   Sakaguchi T (Physics Dep, Brookhaven National Laboratory, Upton, NY 11973-5000, USA, Email: takao@bnl.gov) : Photon and dilepton production in high energy heavy ion collisions. Pramana J Phys 2015, 84(5), 845-59.

Recent results on direct photons and dileptons in high-energy heavy-ion collisions, obtained particularly at Relativistic Heavy Ion Collider (RHIC) and Large Hadron Collider (LHC) are reviewed. The results are new not only in terms of the probes, but also in terms of the precision. We shall discuss the physics learned from the results.

15 illus, 48 ref

008017   Roy S C (NO, Indian National Science Academy, INSA, Delhi, Email: suprakash.roy@gmail.com) : Early years of X-ray research in India. Sci Cult 2015, 81(3-4), 72-5.

X-ray was discovered in 1895 by Wilhelm C Roentgen using Crookes tube. While investigating X-ray research work in India immediately after the discovery of X-rays under the project "History of X-ray Research in India" under the sponsorship of the Indian National Science Academy (INSA), we have uncovered, some new information in connection with the X-ray apparatus built by Acharya Jagadish Chandra, Bose (1858-1937) and the research he had done, which, to the best knowledge of the author, has not been presented before. X-ray research in India has a history from the time of the discovery of X-rays. It is known that Jagadish Chandra Bose (JCB) had built an X-ray apparatus in 1897 while he 'was in Presidency Collge, Calcutta with the help of his assistant in Presidency College. We found out that his X-ray machine was used for clinical diagnostics in patients with broken bones by a physician no less than Sir Nilratan Sircar. However, because of unavailability of his apparatus in Bose Institute or in any museum or any authentic document, it raised some doubts in a section of people about the photographs he had taken using his machine. We have been able to find a press report published in the Calcutta based English daily The Amrita Bazar Patrika in its 5th May edition of 1898 which gives us some idea about his apparatus and the experiment he performed. Using the description available in this document we have tried to come up with a schematic diagram of the apparatus he had used. This report also contradicts the comments made by some authors that JCB had not taken X-ray photograph using Barium Platino cyanide before 1901.

2 illus, 10 ref

008016   Roland G (NO, Massachusetts Institute of Technology, Cambridge, MA 02139, USA, Email: rolandg@mit.edu) : Long range correlations in high multiplicity pp and pa collisions. Pramana J Phys 2015, 84(5), 731-46.

This review summarizes recent discoveries in high-energy proton+proton and proton+nucleus collisions, with particular attention on the observation of long-range azimuthal correlations in high multiplicity collisions. These correlations, which resemble those seen in ultra-relativistic nucleus-nucleus collisions, provide a unique window into the physics of the very early collision stage in high energy nuclear interactions. Here we present a compilation of the most important experimental results and briefly discuss successes and challenges for a selection of theoretical approaches.

1 illus, 80 ref

008015   Ramachandran K;et al (Nuclear Physics Div, Bhabha Atomic Research Centre, Mumbai-400 085, Email: kram@barc.gov.in) : Fission time-scale from the measurement of pre-scission light particles and y-ray multiplicities. Pramana J Phys 2015, 85(2), 335-43.

Overview of the experimental result on simultaneous measurement of pre-scission neutron, proton, α-particle and GDR γ-ray multiplicities for the reaction ^{28Si+175Lu at 159 MeV using the BARC-TIFR Pelletron-LINAC accelerator facility is given. The data were analysed using deformation-dependent particle transmission coefficients, binding energies and level densities which are incorporated in the code JOANNE2 to extract fission time-scales and mean deformation of the saddle-to-scission emitter. The neutron, light charged particle and GDR γ-ray multiplicity data could be explained consistently. The emission of neutrons seems to be favoured towards larger deformation as compared to charged particles. The pre-saddle time-scale is deduced as (0-2) x 10-21 s whereas the saddle-to-scission time-scale is (36-39) x 10-21 s. The total fission time-scale is deduced as (36-41) x 10-21 s.}

4 illus, 35 ref

008014   Prakash M (Physics and Astronomy Dep, Ohio Univ, AThens, OH 45701, USA, Email: prakash@phy.ohiou.edu) : Neutron stars as probes of extreme energy density matter. Pramana J Phys 2015, 84(5), 927-41.

Neutron stars have long been regarded as extraterrestrial laboratories from which we can learn about extreme energy density matter at low temperatures. In this article, some of the recent advances made in astrophysical observations and related theory are highlighted. Although the focus is on the much needed information on masses and radii of several individual neutron stars, the need for additional knowledge about the many facets of neutron stars is stressed. The extent to which quark matter can be present in neutron stars is summarized with emphasis on the requirement of non-perturbative treatments. Some longstanding and new questions, answers to which will advance our current status of knowledge, are posed.

3 illus, 3 tables, 49 ref

008013   Pal S (Nuclear and Atomic Physics Dep, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai-400 005, Email: spal@tifr.res.in) : Transport models for relativistic heavy ion collisions at relativistic heavy ion collinder and large hadron collinder. Pramana J Phys 2015, 84(5), 717-30.

Authors review the transport models that are widely used to study the properties of the quark-gluon plasma formed in relativistic heavy-ion collisions at RHIC and LHC. We show that transport model analysis of two important and complementary observables, the anisotropic flow of bulk hadrons and suppression of hadron yields at high transverse momentum, provide exciting new information on the properties of the plasma formed.

3 illus, 95 ref

008012   Pal S (NO, , Cs-61, Golf Green, Kolkata-700 095, Email: santanupal1950@gmail.com) : Dynamical features of nuclear fission. Pramana J Phys 2015, 85(2), 251-66.

It is now established that the transition-state theory of nuclear fission due to Bohr and Wheeler underestimates several observables in heavy-ion-induced fusion-fission reactions. Dissi-pative dynamical models employing either the Langevin equation or equivalently the Fokker-Planck equation have been developed for fission of heavy nuclei at high excitations (T <126>1 MeV or higher). Here, we first present the physical picture underlying the dissipative fission dynamics. We mainly concentrate upon the Kramers' prescription for including dissipation in fission dynamics. We discuss, in some detail, the results of a statistical model analysis of the pre-scission neutron multiplicity data from the reactions ^{19F+ 194,196,198Pt using Kramers' fission width. We also discuss the multidimensional Langevin equation in the context of kinetic energy and mass distribution of the fission fragments.}

14 illus, 1 table, 37 ref

008011   Navarkhele V V;Kapre A K;Shaikh A A (Physics Dep, Dr Babasaheb Ambedkar Marathwada Univ, Aurangabad-431 004, Email: vvn_bamu@yahoo.co.in) : Dielectric properties of black soil with chemical fertilizers at X-band. Indian J Radio Space Phys 2015, 44(2), 102-5.

Dielectric properties of black soil with the addition of chemicals were measured at microwave frequency. The dielectric measurements have been achieved by using X-band set up. The dielectric properties, that is dielectric constant (ε') and dielectric loss (ε") have been measured for two frequencies (8 and 10 GHz) at room temperature. From the experimental data, it is confirmed that the dielectric constant and dielectric loss increase with increasing percentage volume of chemical fertilizers and decrease with increase in frequency of oscillation. The results also show that the dielectric constant and dielectric loss are higher for the urea than that of potassium carbonate.

4 tables, 20 ref

008010   Nasirov A;Oeertzen W V;Tashkhodjaev R B (NO, Joint Institute for nuclear Research, 141980 Dubna, Moscow Region, Russia, Email: nasirov@jinr.ru) : Nuclear shell effect and collinear tripartition of nuclei. Pramana J Phys 2015, 85(2), 367-78.

A possibility for the formation of three reaction products having comparable masses at the spontaneous fission of ^{252Cf is theoretically explored. This work is aimed to study the mechanism leading to the observation of the reaction products with masses M₁ = 136-140 and M₂ = 68-72 in coincidence with the FOBOS group in JINR. The same type of ternary fission decay has been observed in the 235U(n_th, fff) reaction. The potential energy surface (PES) for the ternary system forming a collinear nuclear chain is calculated for a wide range of masses and charge numbers of the constituent nuclei. The results of the PES for the tripartition of 252Cf(sf, fff) allows us to establish dynamical conditions leading to the formation of fragments with mass combinations of clusters 68-70Ni with 130-132Sn and with the missing cluster 48-52Ca.}

10 illus, 1 table, 24 ref

008009   Naguib I A;Abdelaleem E A;Draz M E;Zaazaa H E (Pharmaceutical Analytical Chemistry Dep, Faculty of Pharmacy, Beni-Suef Univ, 62111, Beni-Suef, Egypt, Email: ibrahim.yaseen@pharm.bsu.edu.eg) : Development and validation of RP-HPLC method for determination of hydrochlorothiazide, amiloride hydrochloride and related impurities in bulk and pharmaceutical dosage forms. Analyt chem Lett 2015, 5(2), 85-93.

Hydrochlorothiazide (HCZ) and Amiloride hydrochloride (AMH) are generally co-formulated in antihypertensive formulations. Different analytical methods have been developed for their simultaneous determination in their binary mixtures but none of them analyzed both drugs in the presence of related impurities of HCZ; Salamide (DSA) and Chlorothiazide (CTZ). Accordingly; a simple, sensitive and highly selective RP-HPLC method was developed for their simultaneous determination in pure form and pharmaceutical formulations. Chromatographic separation was carried out within 10 min using an ODS- C₁₈ column (250 x 4.6 mm, 5 μm) using 0.05 M KH₂PO₄: acetonitrile: triethylamine (90:10:0.3 by volume, pH 3.6) as mobile phase, flow rate 1.5 mL min^{-1 with UV detection at 260 nm.Calibration curves were builtin the range of 1 -50, 1 -20,1-12 and 1 - 20 μg mL-1 for HCZ, AMH, DSA and CTZ, respectively. HCZ and AMH were successfully analyzed in their pure and pharmaceutical form. The results obtained were statistically compared to those obtained by the reported method with no significant difference, therefore the proposed method can be applied in routine quality control analysis of the drug products.}

2 illus, 4 tables, 31 ref

008008   Mazumdar I (NO, Tata institute of Fundamental Research, Mumbai-400 005, Email: indra@tifr.res.in) : Fission hindrance and nuclear viscosity. Pramana J Phys 2015, 85(2), 357-65.

Authors discuss the role of nuclear viscosity in hindering the fission of heavy nuclei as observed in the experimental measurements of GDR γ-ray spectra from the fissioning nuclei. We review a set of experiments carried out and reported by us previously [see Dioszegi et al, Phys. Rev. C 61, 024613 (2000); Shaw et al, Phys. Rev. C 61, 044612 (2000)] and argue that the nuclear viscosity parameter has no apparent dependence on temperature. However, it may depend upon the deformation of the nucleus.

4 illus, 26 ref

008007   Majumder A (Physics and Astronomy Dep, Wayne State Univ, Detroit, Michigan 48201, USA, Email: abhijit.majumder@wayne.edu) : Jet modification in the next decade: a pedestrian outlook. Pramana J Phys 2015, 84(5), 821-43.

In this review, we recount the current status of the theory of jet modification in dense matter. We commence with an outline of the 'traditional' observables which may be calculated without recourse to event generators. These include single- and double-hadron suppression, nuclear modification factor vs. reaction plane etc. All these measurements are used to justify both the required underlying physical picture of jet modification as well as the final obtained values of jet transport coefficients. This is followed by a review of the more modern observables which have arisen with the ability to reconstruct full jets, and the challenges faced therein. This is followed by a preview of upcoming theoretical developments in the field and an outlook on how the interface between these developments, phenomenological improvements, and upcoming data will allow us to quantitatively determine properties of the medium which effect the modification of hard jets.

10 illus, 110 ref