015478   Khan S U D;Arora M;Puri C;Wahab M A;Saini P (NO, , Physics Dep, Jamia Millia Islamia, New Delhi-110 025) : Synthesis and characterization of acrylic resin/activated carbon composites. Indian J pure appl Phys 2014, 52(4), 251-4.

Activated Charcoal (AC) filled acrylic resin (AR) based composites have been prepared by solution processing technique. Different compositions were formulated by variation of AC content between 1 to 30 wt % and the formed composites have been characterized by various techniques to establish a correlation between the filler concentration and the structural, thermal, electrical and morphological attributes. The FTIR spectra show the presence of AC in AR matrix whereas XRD patterns confirm the incorporation of AC particles between lamellar structures of AR. The TGA investigation revealed that composites are thermally stable up to 200°C after which they display multistep weight loss due to removal of functional groups and decomposition/carbonization of AC as well as polymeric backbone of AR. The SEM images show that incorporation of AC particles leads to systematic change in the morphology of composites. The electrical measurements show that 30 wt % AC loading composite displays much lower resistivity (10^{4 Ω/Sq) as compared to pure AR (1011 Ω/Sq) and suggest its suitability as static dissipative material. Further, the porous structure and electrically conducting nature of the composites suggest their suitability for making electromagnetic interference shielding coatings.}

5 illus, 36 ref

015477   Kelkar N G;Nowakowski M;Bedoya Fierro D (de Fisica Dep, Cra 1E, 18A-10, Universidad de los Andes, Bogot , Colombia, Email: nkelkar@uniandes.edu.co) : Opportunities and problems in determining proton and light nuclear radii. Pramana J Phys 2014, 83(5), 761-71.

Briefly review the so-called `proton puzzle', i.e., the disagreement of the newly extracted value of the proton charge radius rp from muonic hydrogen spectroscopy with other extractions, its possible significance and related problems. After describing the conventional theory to extract the proton radius from atomic spectroscopy we focus on a novel consistent approach based on the Breit equation. With this new tool, we confirm that the radius has indeed become smaller compared to the value extracted from scattering experiments, but the existence of different theoretical approaches casts some doubt on the accuracy of the new value. Precision measurements in atomic physics do provide the opportunity to extract light nuclear radii but the accuracy is limited by the methods of incorporating the nuclear structure effects.

26 ref

015476   Kalakonda P;Kashuri H;Kashuri K;Innacchione G S (Physics Dep, Worcester Polytechnic Institute, Worcester, MA 01609, USA, Email: parvathalu.k@gmail.com) : Calorimetric and dielectric study of a negative dielectric anisotropy alkoxy-phenyl-benzoate liquid crystal. Indian J pure appl Phys 2014, 52(10), 689-98.

Modulated Differential Scanning Calorimetry (MDSC) and dielectric spectroscopy have been used to measure the complex specific heat and dielectric constant over a wide temperature range on heating and cooling for a negative dielectric anisotropy alkoxyphenylbenzoate liquid crystal, denoted 9OO4. The MDSC experimental parameters were varied in order to yield quasi-static specific heat results and the same base scan rate was used for the dielectric measurements. On cooling, 9OO4 exhibits a typical weakly first-order isotropic to nematic then a continuous nematic to smectic-A phase sequence followed by a monotropic smectic-C and smectic-B phases before crystallizing. The smectic-B conversion is very slow, even for our quasi-static scan parameters. On heating, the crystal phase super-heats and exhibits a strong first-order transition into an unknown smectic phase that itself converts to the smectic-A phase via a first-order, highly rate dependent, phase transition. The nematic-smectic-A transition has an unusual character given the molecular structure of 9OO4 that may be related to combination of molecular structure and a negative dielectric anisotropy.

9 illus, 20 ref

015475   Jianping Z;Guoliang C;Xiao C;Yi H;Tingjun Z; Yingji Q (College of Energy and Mechanical Engineering, Shanghai Univ of Electric Power, Shanghai 200090, China, Email: jpzhanglzu@163.com ) : Accelerated life test of white OLED based on lognormal distribution. Indian J pure appl Phys 2014, 52(10), 671-7.

In order to acquire the life information of white organic light-emitting diode (WOLED), an accelerated life test (ALT) model was established with increased working current. The lognormal distribution was applied to describe the life distribution, while the least square method (LSM) was employed to estimate the logarithm mean value and the logarithm standard deviation. Statistics and analysis on constant stress and step stress test data were performed by using the self-developed software. The numerical results show that the WOLED life is consistent with lognormal distribution and the accelerated model meets the inverse power law. The key acceleration parameter, which was calculated accurately, enables a rapid estimation of WOLED life.

5 illus, 4 tables, 15 ref

015474   Jiang T;Gong Q;Qiu R;Wang A (College of Mechanical Engineering, Tongji Univ, 4800<35> Cao' an Road, Shanghai 201804, China, Email: 2012gongqiwei@tongji.edu.cn) : Immiscible multicomponent lattice boltzmann model for fuilds with high relaxation time ratio. Pramana J Phys 2014, 83(4), 557-70.

An immiscible multicomponent lattice Boltzmann model is developed for fluids with high relaxation time ratios, which is based on the model proposed by Shan and Chen (SC). In the SC model, an interaction potential between particles is incorporated into the discrete lattice Boltzmann equation through the equilibrium velocity. Compared to the SC model, external forces in our model are discretized directly into the discrete lattice Boltzmann equation, as proposed by Guo et al. We develop it into a new multicomponent lattice Boltzmann (LB) model which has the ability to simulate immiscible multicomponent fluids with relaxation time ratio as large as 29.0 and to reduce 'spurious velocity'. In this work, the improved model is validated and studied using the central bubble case and the rising bubble case. It finds good applications in both static and dynamic cases for multicomponent simulations with different relaxation time ratios.

9 illus, 2 tables, 21 ref

015473   Jeevarekha A;Santhiah M;Philominathan P (Physics P.G. and Research Dep, A.V.V.M. Sri Pushpam College (Autonomous), Poondi, Thanjavur-613 503, Email: philominathan@gmail.com) : Enriched vibrational resonance iin certain discrete systems. Pramana J Phys 2014, 83(4), 493-504.

Report the occurrence of vibrational resonance in certain discrete systems like sine square map and sine circle map, in a unique fashion, comprising of multiple resonant peaks which pave the way for enrichment. As the systems of our choice are capable of exhibiting vibrational resonance behaviour unlike the earlier reports, they are taken for investigation and thenecessary numerical and analytical results are presented. Further, we study the effect of external forcing on various attractors of these systems with appropriate bifurcation and Lyapunov exponent diagrams.

11 illus, 22 ref

015472   Jasin B K;Upadhyay N J (UM-DAE Centre for Excellence in Basic Sciences, Mumbai University, Mumbai-400 098, Email: brajeshk@gmail.com) : Role of near threshold resonances in intermediate energy nuclear physics. Pramana J Phys 2014, 83(5), 749-59.

Presence of a resonance close to the threshold strongly effects the dynamics of the interacting particles at low energies. Production of ^{12C, the element for life, in 4He burning in Sun is a classic example of such a situation. In intermediate energy nuclear physics, this situation arises in the interactions of an χ-meson with a nucleon and that of a K--meson with a proton at low energies, where both these systems have a resonance or a bound state near their thresholds, resulting in a strong attractive interaction. If putting these mesons in nuclear environment produces a strong attraction, it is possible that, in nature there may exist χ- and K--nuclear bound states. Such a tantalizing possibility has led to experimental and theoretical programmes to search for them. These efforts have produced positive results. This paper gives a brief critical overview of these studies, emphasizing especially the efforts led by Bhabha Atomic Research Centre (BARC).}

6 illus, 3 tables, 32 ref

015471   Jafari A;Ghoranneviss M;Hantehzadeh M R; Alipour R (NO, Plasma Physics Research Center, Science and Research Campus, Islamic Azad Univ, Tehran, Iran, Email: jafari_82@yahoo.com) : Numerical study of the lattice vacancy effects on the quantum transport of four-terminal graphene nanodevice. Indian J pure appl Phys 2014, 52(10), 678-83.

The electronic transport properties of four-terminal graphene nanodevice have been investigated by means of the Landauer approach using tight-binding model. The effects of single vacancy and divacancy on transport properties of the electron injected into the system have been studied. The existence of single vacancy along with the magnetic field creates additional band between Landau levels, this effect is appeared by enhancing the transmission. It is also found that in the presence of divacancy with small distance, the coupling between two vacancies due "vacancy molecules", that the bonding between these vacancies can be tuned by the magnetic field. The effect of vacancies decreases when the size of conductor region increases. The theoretical results obtained, can be a base for development in designing graphene nanodevice.

6 illus, 33 ref

015470   Gurbinder Kaur;Pandey O P;Singh K (Material Science and Engineering Dep, Holden Hall, Virginia Tech, Blacksburg, Virginia-24060, USA, Email: gkaur82@vt.edu) : Electronic microscopic, thermal and electrical properties of Bi₂ V_1-xTi_xO_5.50-δ (0.05≤x≤0.20) oxide ion conductors. Indian J pure appl Phys 2014, 52(4), 262-70.

In the present study, the effect of titanium substitution for vanadium on oxide ion conductivity, phase stability and thermal expansion has been investigated. The exact solid solubility limit of the dopant and its effect on conductivity as well as thermal expansion, have been studied. The samples have been prepared by conventional solid-state technique. The sintered samples were characterized using differential thermal analysis (DTA), thermo-gravimetric analysis (TGA), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Sample x = 0.20 has shown maximum conductivity of 1.210^{-3 S/cm with minimum activation energy of 0.19 eV at 800°C. Along with this, maximum thermal expansion coefficient (TEC) is observed for x = 0.2 sample. The microstructures of the samples exhibited variation in grain size and porosity.}

6 illus, 5 tables, 37 ref

015469   Ganesamurthy K;Muruganantham S (Physics Dep, Urumu Dhanalakshmi College, Trichy-620 019, Email: smuruga_physics@yahoo.in) : Light flavor asymmetry of polarized quark distributions in thermodynamical bag model. Indian J pure appl Phys 2014, 52(4), 219-23.

4 illus, 19 ref

015468   Freer M (School of Physics and Astronomy, University of Birmingham, Birmingham, B15 2TT, United Kingdom, Email: M.Freer@bham.ac.uk) : Structure of <. Pramana J Phys 2014, 83(5), 643-50.

Nucleus ^{12C has a rather significant role in modern nuclear physics, but whose influence can be traced to the work of Hoyle in the 1950s, when it was concluded that there should be a state close to 7.68 MeV responsible for the synthesis of carbon in stellar nucleosynthesis. Although a state at 7.65 MeV was subsequently discovered, its properties have remained something of a mystery until rather recently. This paper explores our current understanding of the structure of 12C, in particular the nature of the Hoyle state.}

2 illus, 24 ref

015467   Dang N D (RIKEN Nishina Center for Accelerator-Based Science, , RIKEN 2-1 Hirosawa, Wako City, 351-0198 Saitama, Japan, Email: dang@riken.jp) : Viscosity: from air to hot nuclei. Pramana J Phys 2014, 83(5), 683-93.

After a brief review of the history of viscosity from classical to quantal fluids, a discussion of how the shear viscosity χ of a finite hot nucleus is calculated directly from the width and energy of the giant dipole resonance (GDR) of the nucleus is given in this paper. The ratio χ/s with s being the entropy volume density, is extracted from the experimental systematic of GDR in copper, tin and lead isotopes at finite temperature T . These empirical results are compared with the results predicted by several independent models, as well as with almost model-independent estimations. Based on these results, it is concluded that the ratio χ/s in medium and heavy nuclei decreases with increasing T to reach (1.3-4)xh /(4πkB) at T = 5 MeV, which is almost the same as that obtained for quark-gluon plasma atT <62>170 MeV.

2 illus, 26 ref

015466   Dai Z;Wang C;Liu J (School of Mathematics and Physics, Yunnan Univ, Kunming 650091, People's Republic of China, Email: wcj20082002@aliyun.com) : Inclined periodic homoclinic breather and rogue waves for the (1+1)-dimensional boussinesq equatiion. Pramana J Phys 2014, 83(4), 473-80.

A new method, homoclinic (heteroclinic) breather limit method (HBLM), for seeking rogue wave solution to nonlinear evolution equation (NEE) is proposed. (1+1)-dimensional Boussinesq equation is used as an example to illustrate the effectiveness of the suggested method. Rational homoclinic wave solution, a new family of two-wave solution, is obtained by inclined periodic homoclinic breather wave solution and is just a rogue wave solution. This result shows that rogue wave originates by the extreme behaviour of homoclinic breather wave in (1+1)-dimensional nonlinear wave fields.

2 illus, 30 ref

015465   Dai M;Liu J;Zhu F (Nonlinear Scientific Research Center, Faculty of Science, Jiangsu Univ, Zhenjiang, Jiangsu 212013, People's Republic of China, Email: daimf@ujs.edu.cn) : Biased trapping issue on weighted hierarchical networks. Pramana J Phys 2014, 83(4), 481-91.

In this paper, author present trapping issues of weight-dependent walks on weighted hierarchical networks which are based on the classic scale-free hierarchical networks. Assuming that edge's weight is used as local information by a random walker, we introduce a biased walk. The biased walk is that a walker, at each step, chooses one of its neighbours with a probability proportional to the weight of the edge. We focus on a particular case with the immobile trap positioned at the hub node which has the largest degree in the weighted hierarchical networks. Using a method based on generating functions, we determine explicitly the mean first-passage time (MFPT) for the trapping issue. Let parameter a (0 <60> a <60> 1) be the weight factor. We show that the efficiency of the trapping process depends on the parameter a; the smaller the value of a, the more efficient is the trapping process.

3 illus, 22 ref

015464   Chakrabarty D R (Nuclear Physics Div, Bhabha Atomic Research Centre, , Mumbai-400 085, Email: dr_chakrabarty@yahoo.com) : Electromagnetic transition between molecular resonances in <. Pramana J Phys 2014, 83(5), 635-42.

Nucleus ^{8Be has been conjectured to resemble a molecule of two interacting α-particles. A crucial test of this conjecture is the electromagnetic transition between the molecular resonances. This paper discusses the earlier indirect bremsstrahlung measurements and describes a recent experiment on the direct measurement of γ -transition between the 4+ and 2+ resonances. Experimental results are compared with various theories. The outlook on the measurement of 2+ → 0+ transition will be presented.}

4 illus, 1 table, 20 ref

015463   Bhattacharya S;Rana T K;Bhattacharya C;Kundu S;Banerjee K;Ghosh T K;Mukherjee G;Pandey R;Roy P (Variable Energy Cyclotron Centre, , 1/AF Bidhan Nagar, Kolkata-700 064, Email: saila@vecc.gov.in) : Decay of Hoyle state. Pramana J Phys 2014, 83(5), 673-82.

Prediction of Hoyle state was necessitated to explain the abundance of carbon, which is crucial for the existence of life on Earth and is the stepping stone for understanding the abundance of other heavier elements. After the experimental confirmation of its existence, soon it was realized that the Hoyle state was `different' from other excited states of carbon, which led to intense theoretical and experimental activities over the past few decades to understand its structure. In recent times, precision, high statistics experiments on the decay of Hoyle state have been performed at the Variable Energy Cyclotron Centre, to determine the quantitative contributions of various direct 3à decay mechanisms of the Hoyle state. The present results have been critically compared with those obtained in other recent experiments and their implications have been discussed.

6 illus, 26 ref

015462   Bhattacharya R (NO, Calcutta Univ, 92 A.P.C. Road, Kolkata-700 009, Email: rup_bhat@hotmail.com) : Emergence of new magic numbers, N = 16 and 32 by tensor interaction in skyrme-hartree-fock theory. Pramana J Phys 2014, 83(4), 519-32.

Melting of N = 20 shell and development of N = 16 and 32 shells for neutronrich nuclei have been studied extensively by including tensor interaction in Skyrme-Hartree-Fock theory optimized to reproduce the splitting Δ1f shells of ^{40,48Ca and 56Ni nuclei. Evolution of gap generated by the energy difference of single-particle levels ν2s1/2 and ν1d3/2 has been found to be responsible for shell closure at N = 16. The splitting pattern of spin-orbit partners 2p shell model state in Ca, Ti, Cr, Fe and Ni isotopes indicates the formation of a new shell at N = 32 region.}

4 illus, 6 tables, 36 ref

015461   Batra J;Jaiswar A;Srivastava R;Niranjan R; Rout R K;Kaushik T C (Applied Physics Div, Bhabha Atomic Research Centre, Trombay, Mumbai-400 085, Email: jigyasa@barc.gov.in) : Low and high energy deuterium ions emission in a 4.7 kJ plasma focus device and its variation with gas filling pressure. Indian J pure appl Phys 2014, 52(4), 246-50.

Plasma Focus (PF) being a good source of electromagnetic radiations, ions and electrons, their characterization could be helpful in understanding the dynamics and various processes undergoing in this device. The emission of deuterium ions from PF at different filling gas pressures in the range 1-5 mbar has been studied in the present paper. An anti conical Faraday Cup (FC) has been designed and developed to detect ion flux. From the recorded signals, two peaks have been observed corresponding to low energy (a few eV) and high energy (few keV to hundreds of keV) ions. This study on measurement of poly energy ions flux at different filling gas pressures shows that the ratio of higher energy ions flux to lower energy ions flux increases with lowering the pressure and could be attributed to anomalous resistance in PF device.

6 illus, 22 ref

015460   Barik S K;Chatterjee S;Choudhary R N P (Physics Dep, National Institute of Technology Silchar, Silchar-788 010, Email: subrat.nits@gmail.com) : Molecular and impedance spectroscopy of Na₂Mo₂O₇ ceramics. Pramana J Phys 2014, 83(4), 571-7.

The fine (i.e. 38 nm) powder of polycrystalline Na₂Mo₂O₇ was prepared by the hightemperature solid-state reaction technique. The formation of the compound in orthorhombic system is confirmed by preliminary structural analysis using X-ray diffraction (XRD) data. Spectroscopic studies of the compound have been carried out by vibration spectroscopy (Raman/FTIR) to understand its molecular structure at microscopic level. The complex impedance spectroscopy (CIS) technique has been used to study the electrical properties of the material as a function of frequency (10^{2-106 Hz) at different temperatures (23-450°C), and also to investigate the fundamental mechanism involved in the material. Impedance analysis also indicates that below 300°C, the electrical conduction in the material is due to grain interior only. At and above 325°C, the contribution of grain boundary is clearly evident. The electrical processes in the material are found to be temperature-dependent and are due to the relaxation phenomena in it. A frequency-dependent maximum of the imaginary electrical impedance is found to obey the Vogel-Fulcher law.}

5 illus, 1 table, 16 ref

015459   Balabanski D L (ELI-NP, IFIN-HH, , 30 Reactorului Str., 077125 Bucharest-Magurele, Romania) : Physics studies with brilliant narrow-width γ -beams at the new ELI-NP Facility. Pramana J Phys 2014, 83(5), 713-18.

Extreme Light Infrastructure Nuclear Physics (ELI-NP) Facility in Magurele is a European research centre for ultrahigh intensity lasers, laser-matter interaction, nuclear science and material science using laser-driven radiation beams. It is the first project within the European Strategic Forum for Research Infrastructure (ESFRI) agenda financed by the European Regional Development Fund. The nuclear physics research programme of the facility is focussed on studies with brilliant narrow-width γ -beams and experiments in extreme laser fields.

2 illus, 11 ref

015458   Bahceli S;Gokce H (Physics Dep, Suleyman Demirel Univ, Faculty of Arts and Sciences, East Cunur Campus, 32260, Isparta, Turkey, Email: semihabahceli@sdu.edu.tr) : Spectroscopic and quantum chemical calculations of levosimendan. Indian J pure appl Phys 2014, 52(4), 224-35.

In the present study, FT-IR, micro-Raman and UV-Vis. spectra of levosimendan molecule, (C₁₄H₁₂N₆O), have been experimentally recorded and the molecular geometry, vibrational frequencies, electronic absorption spectrum, HOMO-LUMO analysis, natural bond orbital (NBO) analysis, molecular electrostatic potential (MEP), thermodynamic properties and atomic charges of title molecule have been calculated by using density functional theory (DFT/B3LYP) method with 6-311++G(d,p) basis set in the ground state. The calculated vibrational results are found to be good agreement with experimental data.

5 illus, 5 tables, 38 ref

015457   Babita;Satish;Singh A;Saxena A K (LF HF Impedance and DC Standard, CSIR National Physical Laboratory, Dr K S Krishnan Marg, New Delhi-110 012, Email: singhb2@nplindia.org) : Determination and Validation of Average value of National Standard of DC Voltage using different methods at CSIR-NPLI. MAPAN 2013, 28(2), 99-104.

Aim of this paper is to evaluate and validate the average value of national or secondary standard of DC voltage, using four different methods; comparison, substitution, difference and ratio method. In the paper the custom made automation program developed to control the whole measurement process is discussed as well. The automation system has been developed in the view of achieving maximal quality of metrological performance i.e. minimum measurement uncertainty and maximum reliability. It is found that measurement automation provides reliable and efficient way for the calibration of Zener based standard of DC voltage.

7 illus, 2 tables, 15 ref

015456   Arif M;Siddhartha;Khan Z R;Gupta V;Singh A (Physics Dep, Mewar Univ, Chittorgarh-312 901, Email: arunsingh07@gmail.com) : Effect of subsrates temperature on structural and optical properties of thermally evaporated CdS nanocrystalline thin films. Indian J pure appl Phys 2014, 52(10), 699-203.

Nanocrystalline thin films of CdS were deposited by thermal evaporation technique under vacuum (p=2 x 10^{-5 torr) on cleaned glass substrates maintained at different temperatures (300, 473 and 573 K). The effect of substrates temperature on structural and optical properties of CdS nanocrystalline thin films has been studied. X-ray diffraction (XRD), ultraviolet-visible (UV-Vis) and Scanning Electron Microscopy (SEM) were used to characterize the CdS nanocrystalline thin films. The optical and structural studies show that film deposited at 300 K was amorphous in nature and films deposited at higher temperatures were crystalline in nature. Optical constants, such as optical band gap was evaluated from these spectra. The optical band gap was found to be in the range 2.38-<126>2.51 eV. The study of structural and some physical properties of CdS films indicates that they are strongly dependent on the substrate temperature. Crystallinity levels became better at high substrate temperatures (especially for the film obtained at 573 K). Using the optical investigations including the band gap calculations, it was determined that the band gap of CdS films decreases with substrate temperature, due to the changes in grain size and crystallinity. There is a random effect of substrate temperature on band tail values.}

4 illus, 2 tables, 29 ref

015455   Ahmad S;Pal B;Negi P S;Bandyopadhyay A K (NO, LF & HF Voltage, Current and Microwave Standards, CSIR National Physic, New Delhi, Email: saood1974@yahoo.co.in) : Assigning RF/DC transfer difference to high frequency voltage primary standard up to 1 GHz at NPLI. MAPAN 2013, 28(2), 113-17.

National Physical Laboratory (NPLI) India is the premier research and development center and the National Metrology Institute, which provides traceability in measurements by calibration throughout the country. High frequency (HF) voltage is one of the important parameter in electrical metrology. At NPLI the primary standard of HF voltage at frequencies from 1 to 1,000 MHz is a twin resistance coaxial power mount. The calibration technique and establishing the traceability by assigning the RF/DC transfer difference to HF voltage primary standard are described in this paper. The HF voltage primary standard has been characterized by assigning RF/DC transfer differences to it in terms of effective efficiency, RF impedance and DC resistance. The calibration results of the primary standard have been discussed in this paper. The assigned RF/DC transfer difference (δ) and the expanded uncertainty of HF voltage primary standard at 1.0 GHz is (-5.2 ± 5.4) mV/V.

s, 1 table, 10 ref

015454   Agrawal S L;Shukla P K;Tripathi D;Singh C P (SSI Laboratory, Physics Dep, APS University, Rewa-486 003) : Ion-transport studies on Ba-nano ferrite dispersed PVA : (NH4CH2COO)2 Polymer Electrolyte. Bhartiya Vaigyanik Evam Audyogik Anusandhan Patrika 2014, 22(1), 46-52.

An attempt has been made in the present work to develop a nano sized Ba-ferrite doped PVA based nano composite polymer gel electrolyte for electrochemical device applications. Nano sized Ba-ferrite particles prepared through chemical route were dispersed in matrix electrolyte of PVA: (NH₄CH₂COO)₂ to obtain NCPGE films. XRD result on a synthesised filler particle depicts formation of nano ferrite with hexaferrite as the major phase. Further XRD studies on NCPGE show improvement in amorphous character with increasing concentration of nano fillers in composite electrolytes. OM and SEM examination of NCPEs shows heterogeneous distribution of fillers. Cyclic voltammetric measurement reveals optimum electrochemical window of ±1.8V with good recyclability. Ionic conductivity of electrolyte evaluated from impedance spectroscopy technique shows enhancement in electrical conductivity upon dispersal of nano fillers which increases with filler concentration and temperature. Jonscher power law seems to be obeyed during ac conductivity measurement of the films.

7 illus, 20 ref

015453   Agrawal B K (NO, Saha Institute of Nuclear Physics, 1/AF Bidhan Nagar, Kolkata-700 064, Email: bijay.agrawal@saha.ac.in) : Density content of nuclear symmetry energy from nuclear Observables. Pramana J Phys 2014, 83(5), 695-704.

Nuclear symmetry energy at a given density measures the energy transferred in converting symmetric nuclear matter into the pure neutron matter. The density content of nuclear symmetry energy remains poorly constrained. Our recent results for the density content of the nuclear symmetry energy, around the saturation density, extracted using experimental data for accurately known nuclear masses, giant resonances and neutron-skin thickness in heavy nuclei are summarized.

5 illus, 23 ref

014571   Zhe Z;Li D (NO, School of Mathematics and System Sciences, Shenyang Normal Univ, Shenyang Liaoning-110 034, Email: lidesheng@synu.edu.cn) : The modified multiple (G'/G)-expansion method and its application to Sharma-Tasso-Olver equation. Pramana J Phys 2014, 83(1), 95-105.

The modified multiple (G'/G)-expansion method is proposed in this paper to construct exact solutions of nonlinear evolution equations. The validity and advantage of the proposed method are illustrated by its application to the Sharma-Tasso-Olver equation. As a result, various exact solutions including hyperbolic functions, trigonometric functions and their mixture with parameters are obtained. When some parameters are taken as special values, the known double solitary-like wave solutions are derived from the double hyperbolic function solution. It is shown that the method introduced in this paper has general significance in searching for exact solutions to the nonlinear evolution equations.

21 ref

014570   Yahya W A;Oyewumi K J;Sen K D (Theoretical Physics Section, Physics Dep, Ilorin Univ, Nigeria, Email: mjpysics@yahoo.com) : Information and complexity measures for the ring-shaped modified kratzer potential. Indian J Chem-Sect A 2014, 53(10), 1307-16.

In this study, the Fisher information measure, Shannon entropy, Renyi entropy, Tsallis entropy and Fisher-Shannon complexity of the ring-shaped modified Kratzer potential are investigated. The trends in the variation of the information and complexity measures considered for this model quantum system are discussed.

11 illus, 67 ref

014569   Unsal O;Tascan F;Naci Ozer M (Mathematics and Computer Sciences Dep, Eskisehir Osmangazi Univ, Art Science Faculty, Eskisehir-Turkiye, Email: ftascan@ogu.edu.tr) : Multiscale expansions in discrete world. Pramana J Phys 2014, 83(1), 21-8.

Showed the attainability of KdV equation from some types of nonlinear Schrodinger equation by using multiscale expansions discretely. The power of this manageable method is confirmed by applying it to two selected nonlinear Schrodinger evolution equations. This approach can also be applied to other nonlinear discrete evolution equations. All the computations have been made with Maple computer packet program.

14 ref

014568   Thirukkanesh S;Ragel F C (Mathematics Dep, Eastern Univ, Chenkalady, Sri Lanka, Email: thirukkanesh@yahoo.co.uk) : Anisotropic spheres with van der waals-type equation of state. Pramana J Phys 2014, 83(1), 83-93.

It studies static spherically symmetric space-time to describe relativistic compact objects with anisotropic matter distribution and derive two classes of exact models to the Einstein-Maxwell system with a modified Van der Waals equation of state. We motivate a Van der Waals-type equation of state to physically signify a high-density domain of quark matter, and the generated exact solutions are shown to contain several classes of exact models reported previously that correspond to various physical scenarios. Geometrical analysis shows that the physical quantities are well behaved so that these models may be used to describe anisotropic charged compact spheres.

10 illus, 22 ref

014567   Thakur R K;Leiderer P (Physics Dep, Konstanz Univ, Universitaet Strasse 10, D-78464 Konstanz, Germany, Email: thakur@lnl.infn.it) : New experimental approach on charging technique of helium surface over rectangular electrodes at cryogenic temperature. Curr Sci 2014, 107(7), 1146-50.

We report results on the charging technique of liquid helium surface over rectangular electrodes and maximum sustainable electron density at temperatures above 1 K. Also, thermally activated escape of two-dimensional electrons from the potential well has been studied as a function of various parameters like electrons density and temperature. Results provide insights into the charging process of the surface-state electrons and their stability parameters over these electrodes with AC capacitive coupling technique.

6 illus, 10 ref

014566   Singh V;Tiwari V B;Singh S;Mishra S R;Rawat H S (NO, Laser Physics Applications Section, Raja Ramanna Centre for Advanced T, Indore-452 013, Email: viveksingh@rrcat.gov.in) : The effect of laser beam size in a zig-zag collimator on transverse cooling of a krypton atomic beam. Pramana J Phys 2014, 83(1), 131-8.

The effect of size of a cooling laser beam in a zig-zag atomic beam collimator on transverse cooling of a krypton atomic beam is investigated. The simulation results show that discreteness in the interaction between the cooling laser beam and atomic beam, arising due to finite size and incidence angle of the cooling laser beam, significantly reduces the value of transverse velocity capture range of the collimator. The experimental observations show the trend similar to that obtained from simulations. Our study can be particularly useful where a small zig-zag collimator is required.

5 illus, 21 ref

014565   Singh C P (Applied Mathematics Dep, Delhi Technological Univ, Bawana Road, Delhi-110 042, Email: cpsphd@rediffmail.com) : Some exact solutions of magnetized viscous model in string cosmology. Pramana J Phys 2014, 83(1), 63-81.

In this paper, we study anisotropic Bianchi-V Universe with magnetic field and bulk viscous fluid in string cosmology. Exact solutions of the field equations are obtained by using the equation of state (EoS) for a cloud of strings, and a relationship between bulk viscous coefficient and scalar expansion. The bulk viscous coefficient is assumed to be inversely proportional to the expansion scalar. It is interesting to examine the effects of magnetized bulk viscous string model in early and late stages of evolution of the Universe. This paper presents different string models like geometrical (Nambu string), Takabayasi (p-string) and Reddy string models by taking certain physical conditions. We discuss the nature of classical potential for viscous fluid with and without magnetic field. The presence of bulk viscosity stops the Universe from becoming empty in its future evolution. It is observed that the Universe expands with decelerated rate in the presence of viscous fluid with magnetic field whereas, it expands with marginal inflation in the presence of viscous fluid without magnetic field. The other physical and geometrical aspects of each string model are discussed in detail.

4 illus, 77 ref

014564   Shiv Chaitanya K V S (NO, BITS Pilani, Hyderabad Campus, Jawahar Nagar, Shameerpet Mandal, Hyderabad-500 078, Email: chaitanya@hyderabad.bits-pilani.ac.in) : Stieltjes electrostatic model interpretation for bound state problems. Pramana J Phys 2014, 83(1), 139-45.

In this paper, it is shown that Stieltjes electrostatic model and quantum Hamilton Jacobi formalism are analogous to each other. This analogy allows the bound state problem to mimic as n unit moving imaginary charges ih, which are placed in between the two fixed imaginary charges arising due to the classical turning points of the potential. The interaction potential between n unit moving imaginary charges ih is given by the logarithm of the wave function. For an exactly solvable potential, this system attains stable equilibrium position at the zeros of the orthogonal polynomials depending upon the interval of the classical turning points.

15 ref

014563   Senthamil Selvi C;Ravichandran S;Thillaiyadi Valliammai C;Thenmozhi C;Kannappan V (Physics Dep, Sathyabama Univ, Chennai-600 119, Email: senthamilc@yahoo.co.in) : Acoustical studies of ternary mixtures at different temperatures. Rasayan J Chem 2014, 7(4), 325-32.

The ternary mixture of crotonaldehyde with iodine in n-hexane has been studied extensively from the view point of their acoustic and molecular interaction studies at 293.15, 298.15, 303.15 and 308.15K. Experimental values are used to compute derived parameters. By using the ultrasonic velocity (U), density (ρ) coefficient of viscosity (η), the other acoustical parameters adiabatic compressibility (κ), free length (L_f), interaction parameter (χ_i) and molar volume (V_m) are calculated. The ultrasonic velocity decreases with concentration at 0.006M. It reveals the weak interaction that takes place at 303.15K of the ternary mixtures. The study reveals that weak interaction takes place at higher temperatures of the ternary mixtures.

6 illus, 3 tables, 23 ref

014562   Sengodan R;Chandar Shekar B;Sathish S (Physics Dep, Kumaraguru College of Technology, Coimbatore, Tamil Nadu, Email: chandar.bellan@gmail.com) : Structure, surface morphology and optical properties of BaTiO₃ powders prepared by wet chemical method. Indian J pure appl Phys 2014, 52(12), 839-45.

Barium titanate powders were synthesized by the wet chemical method using the starting materials barium chloride (BaCl₂), titanium dioxide (TiO₂) and oxalic acid with different calcinations temperature. The XRD pattern of BaTiO₃ calcined at 500 °C showed cubic phase whereas BaTiO₃ samples calcined at 700 °C and above showed tetragonal phase. The crystallite size, strain and dislocation density were calculated from the XRD spectrum. It was found that crystallite size increases with increase of calcination temperature. EDS spectrum was used to identify the composition of the material. Absorption co-efficient (α), extinction co-efficient (K) and optical band gap were estimated from the optical reflectance spectrum. The band gap of the powder was found to be decreasing with the increase of calcination temperature. Nanoparticles of both spherical and rod like in shape were clearly observed in the SEM.

15 illus, 1 table, 15 ref

014561   Ravichandram S;Senthamil Selvi C (Physics Dep, Sathyabama Univ, Chennai-600 119, Email: rs_ravichandran@yahoo.com) : Theoretical evaluation of acoustical studies of non linearity parameter (B/A) of sodium dodecyle sulphate in polyvinyl alcohol solution at 303K. Rasayan J Chem 2014, 7(3), 246-51.

The acoustical parameters of sodium dodecyl sulphate (SDS) in poly (vinyl alcohol) (PVA) solution was studied by ultrasonic velocity measurements. Ultrasonic velocity, density, viscosity in mixtures of sodium dodecyl sulphate in polyvinyl alcohol was measured over the entire range of composition. From the data, other related parameters, viz., adiabatic compressibility, intermolecular free length, surface tension were calculated theatrically. Ultrasonic velocities theoretically evaluated using Nomoto's Relation, Impedance Relation, Free Length Theory and it is compared with experimental values to check applicability of these equations to the systems studied. The present investigation comprises of theoretical evaluation of acoustic non-linearity parameter, B/A using Hartmann relation, Ballous empirical relation.

6 tables, 29 ref

014560   Ravi B;Jegatheesan A;Neelakandaprasad B; Sadeeshkumar C;Rajarajan G (Physics Dep, King College of Technology, Namakkal, Tamil Nadu-637-020, Email: raviphysics08@gmail.com) : Optical and conductivity analysis of thiourea single crystals. Rasayan J Chem 2014, 7(3), 287-94.

The Thiourea single crystals have been grown from saturated solution by slow evaporation technique. The crystallinity and structure of pure thiourea single crystals were confirmed using powder XRD and frequency assignments of the various internal modes of vibrations for the functional groups were observed in the FTIR spectroscopy. Transparency and optical studies were carried out by UV-Vis spectroscopy. It shows a good transmittance in the entire visible region and the lower cut off wavelength at 241.67 nm attest the usefulness of this material for optoelectronics applications. Dielectric and conducting studies were done for analysis of its electrical properties. The low values of dielectric loss suggest that the grown crystals have lesser defects.

9 illus, 2 tables, 27 ref

014559   Ramesh Kumar;Fakir Chand (Applied Physices Dep, S D College, Ambala Cantt-133 001, Email: fchand@kuk.ac.in) : Solution of the N-dimensional radial Schrodinger equation for the potential ar₂ + br - c/r. Pramana J Phys 2014, 83(1), 39-48.

Approximate solutions to the N-dimensional radial Schrodinger equation for the potential ar^{2 + br - c/r are obtained by employing the formulation described in Ciftci et al, J. Phys. A 43, 415206 (2010). The problem, for some special cases, is solved numerically. Using this analysis, the energy spectra of a two-dimensional two-electron quantum dot (QD) in a magnetic field are also obtained. The results of this study are in good agreement with the other studies.}

2 illus, 1 tables, 35 ref

014558   Rajotia D;Jat R N (Mathematics Dep, Rajasthan Univ, Jaipur-302 004, Email: rajotia.dinesh@gmail.com) : Dual solutions of three dimensional MHD boundary layer flow and heat transfer due to an axisymmetric shrinking sheet with viscous dissipation and heat generation/absorption. Indian J pure appl Phys 2014, 52(12), 812-20.

An analysis is presented to study the effect of magnetic parameter on the certain range of suction parameter where the similarity solution exists of the three dimensional MHD boundary layer flow and heat transfer due to a porous axisymmetric shrinking sheet. The governing equations are transformed into self-similar non-linear ordinary differential equations by using suitable similarity transformations and then the transformed equations are solved numerically using a shooting method. The numerical results of velocity and temperature profiles as well as skin-friction coefficient and rate of heat transfer at the sheet are obtained and displayed graphically with different pertinent parameters to show interesting aspects of the solution. The investigation explores the conditions of the non-existence, the existence and duality of the similarity solutions which depend not only on the suction parameter S but magnetic parameter M also. The dual solutions exist in a certain domain of suction parameter S and an increment in the magnetic parameter M increases the domain of S where the solution exists. Also, the thickness of the momentum boundary layer and thermal boundary layer for the second solution are thicker than that of the first solution.

15 illus, 1 table, 35 ref

014557   Panahi H;Rahmati H (Physics Dep, Univ of Guilan, Rasht 51335-1914, Iran, Email: t-panahi@guilan.ac.ir) : g₂ algebra and two-dimensional quasiexactly solvable Hamiltonian related to Poschl-Teller potential. Pramana J Phys 2014, 83(1), 3-8.

In this article, authors write the general form of the quasiexactly solvable Hamiltonian of g2 algebra via one special representation in the x-y two-dimensional space. Then, by choosing an appropriate set of coefficients and making a gauge rotation, we show that this Hamiltonian leads to the solvable Poschl-Teller model on an open infinite strip. Finally, we assign g2 hidden algebra to the Poschl-Teller potential and obtain its spectrum by using the representation space of g₂ algebra.

23 ref

014556   Naz R;Mahomed F M (NO, Centre for Mathematics and Statistical Sciences, Lahore School of Econ, Lahore 53200, Pakistan, Email: rehananaz_qau@yahoo.com) : lie and noether symmetries of systems of complex ordinary different equations and their split systems. Pramana J Phys 2014, 83(1), 9-20.

The Lie and Noether point symmetry analyses of a kth-order system of m complex ordinary differential equations (ODEs) with m dependent variables are performed. The decomposition of complex symmetries of the given system of complex ODEs yields Lie- and Noether-like operators. The system of complex ODEs can be split into 2m coupled real partial differential equations (PDEs) and 2m Cauchy-Riemann (CR) equations. The classical approach is invoked to compute the symmetries of the 4m real PDEs and these are compared with the decomposed Lie- and Noether-like operators of the system of complex ODEs. It is shown that, in general, the Lie- and Noether-like operators of the system of complex ODEs and the symmetries of the decomposed system of real PDEs are not the same. A similar analysis is carried out for restricted systems of complex ODEs that split into 2m coupled real ODEs. We summarize our findings on restricted complex ODEs in two propositions.

14 ref

014555   Jiang Y;Tian B;Wang P;Sun K (NO, State Key Laboratory of Information Photonics and Optical Communicatio, Beijing-100 876, Email: tian_bupt@163.com) : Infinitely many conservation laws for two (2+1) dimensional nonlinear evolution equation in fluids. Pramana J Phys 2014, 83(1), 29-37.

In this paper, a method that can be used to construct the infinitely-many conservation laws with the Lax pair is generalized from the (l + l)-dimensional nonlinear evolution equations (NLEEs) to the (2+l)-dimensional ones. Besides, we apply that method to the Kadomtsev-Petviashvili (KP) and Davey-Stewartson equations in fluids, and respectively obtain their infinitely-many conservation laws with symbolic computation. Based on that method, we can also construct the infinitely-many conservation laws for other multidimensional NLEEs possessing the Lax pairs, including the cylindrical KP, modified KP and (2+1)-dimensional Gardner equations, in fluids, plasmas, optical fibres and Bose-Einstein condensates.

29 ref

014554   Jegatheesan A;Ravi B;Neelakanda Prasad B; Rajarajan G (Physics Dep, Paavai Group of Institution, Namakkal-637 018, Email: grajarajan@hotmail.com) : Growth and characterization of promising nonlinear optical GTFA single crystal. Rasayan J Chem 2014, 7(4), 353-8.

This work investigates the growth of promising nonlinear optical single crystal of semi organic optical material Glycine Trifluoro Acetate (GTFA) with the molecular formula CH₂NH₂COOH.CF₃COOH (C₃H₄F₃NO), which has synthesized by slow evaporation technique at constant room temperature. Spectral, thermal and optical techniques have been employed to characterize the new material. The lattice parameters and the crystal system of the crystal was observed by Powder X- ray diffraction method, and identified as Tetragonal. Functional groups present in the sample were identified by FTIR spectral analysis. The optical transmission study shows that the crystal is transparent in the entire visible region with a cutoff wavelength of 327 nm. The optical band gap was found to be 4.1 eV. The Thermo gravimetric analysis (TGA) and differential scanning calorimetry (DSC) analysis of GTFA was determined from the TGA/DSC response curve. The second harmonic generation (SHG) of the GTFA crystal was demonstrated by Kurtz Perry method using Nd: YAG laser and the result confirm that the grown crystal is 60% as that of KDP.

5 illus, 18 ref

014553   Jayalakshmi J;Reddy K K (Physics Dep, Yogi Vemana Univ, Kadapa-516 003, Email: krishna.kkreddy@gmail.com) : Raindrop size distributions of Southwest and Northeast monsoon heavy precipitation observed over Kadapa (14°4'N, 78°82'E), a semi-arid region of India. Curr Sci 2014, 107(8), 1312-20.

Raindrop size distributions (RSD) of southwest (SW -June to September) and northeast (NE - October to December) monsoon heavy precipitation are measured with PARticle SIze and VELocity (PARSIVEL) dis-drometer and Micro Rain Radar (MRR) deployed at Kadapa (14.47°N; 78.82°E), a semi-arid continental site in Andhra Pradesh, India. RSD characteristics stratified on the basis of rainrate showed that the mean values of raindrop concentration of small (medium) drops are less (more) in SW when compared with NE monsoon heavy precipitation. Gamma function applied to heavy precipitation events showed that the mean value of mass weighted mean diameter, D_m (normalized intercept parameter log₁₀N_w) is higher (lower) in SW monsoon than NE monsoon. Stratiform and convective precipitating cloud fraction observed during SW and NE monsoons revealed that contribution of stratiform precipitation is predominant for the seasonal variation in raindrop size distribution. The coefficient and exponent values of the Z-R relations are higher in SW than NE monsoon in both stratiform and convective precipitation.

8 illus, 4 tables, 23 ref

014552   Helen F;Kanchana G (PG and Research Dep of Physics, Government Arts College, Coimbatore-641 018, Email: kanchanagopinath@gmail.com) : Investigation on the properties of L-serine doped zinc tris (thiourea) sulphate crystal for NLO application. Indian J pure appl Phys 2014, 52(12), 821-8.

Single crystals of l-serine doped zinc tris (thiourea) sulphate (LSZTS) were grown by the slow evaporation solution growth technique (SEST) at room temperature. The LSZTS crystals were subjected to powder XRD to confirm the crystalline nature and purity of the crystal. The lattice parameters of LSZTS were obtained from single crystal X-ray diffraction analysis. Fourier transform infrared (FTIR) and Raman (FT-Raman) spectroscopic studies revealed the functional groups present in the doped crystal. Ultraviolet visible (UV-Vis) transmittance spectrum showed that the lower cutoff wavelength of LSZTS was 325 nm. Theoretical calculations were carried out to determine the linear optical constants. Photoluminescence (PL) spectrum of the LSZTS showed blue emission. The thermo gravimetry (TG) and differential scanning calorimetry (DSC) analyses revealed that LSZTS crystal was stable up to 231.9°C. Microhardness study was carried out to assess the mechanical stability of the doped crystal. The work hardening coefficient of LSZTS was estimated. Kurtz Perry powder test was carried out to study the effect of L-serine on the NLO properties of ZTS. The second harmonic generation (SHG) efficiency of LSZTS was found to be enhanced in the presence of a high concentration of dopant.

12 illus, 1 table, 23 ref

014551   Hamzavi M;Ikhdair S M (Science and Engineering Dep, Abhar Branch, Islamic Azad Univ, Abhar, Iran, Email: majid.hamzavi@gmail.com) : Approximate eigensolutions of dirac equation for the superposition hellmann potential under spin and pseudospin symmetries. Pramana J Phys 2014, 83(1), 49-61.

The Hellmann potential is simply a superposition of an attractive Coulomb potential -a/r plus a Yukawa potential be^{-δr /r. The generalized parametric Nikiforov-Uvarov (NU) method is used to examine the approximate analytical energy eigenvalues and two-component wave function of the Dirac equation with the Hellmann potential for arbitrary spin-orbit quantum number K in the presence of exact spin and pseudospin (p-spin) symmetries. As a particular case, we obtain the energy eigenvalues of the pure Coulomb potential in the non-relativistic limit.}

3 tables, 53 ref

014550   Ghosh B;Ghosh A K (NO, School of Energy Studies, J.U., Kolkata-700 032, Email: a.ghosh1@yahoo.co.in) : Effect of dust on solar PV modules efficiency. Sci Cult 2014, 80(9-10), 290-7.

Effect of dust and shadow of Solar Photo Voltaic panels is a natural process. The present study on dustassimilation on the surface of solar PV panels can reduce system out-put to 16-40% in a month investigation. This paper provides current status in studying such impact on PV system performance and identifies challenges to overcome the problem. An experimental framework as designed as changing seasonally to locate diagnostic solution in this regard. If the experiment be performed in long-term basis from local to regional atmospheric conditions then the study will envisage a new paradigm in science and technology.

19 illus, 12 ref

014549   Ghosh A;Vijaya R (Fibre Optics and Photonics Div, Central Glass and Ceramic Research Institute, Council of Scientific an, Kolkata-700 032, Email: rvijaya@iitk.ac.in) : Linear and nonlinear resonance features of an erbium-doped fibre ring laser under cavity-loss modulation. Pramana J Phys 2014, 83(1), 147-59.

The continuous-wave output of a single-mode erbium-doped fibre ring laser when subjected to cavity-loss modulation is found to exhibit linear as well as nonlinear resonances. At sufficiently low driving amplitude, the system resembles a linear damped oscillator. At higher amplitudes, the dynamical study of these resonances shows that the behaviour of the system exhibits features of a nonlinear damped oscillator under harmonic modulation. These nonlinear dynamical features, including harmonic and subharmonic resonances, have been studied experimentally and analysed with the help of a simple time-domain and frequency-domain information obtained from the output of the laser. All the studies are restricted to the modulation frequency lying in a regime near the relaxation oscillation frequency.

6 illus, 20 ref

014548   El Assad Zemallach Quari K;El Jouad Z; Benchouk K;Kouskoussa B;Cattin L;Makha M;Khelil A;Morsli M;Addou M; Bernede J C (NO, LPCMME, Faculte des Sciences, Universite d'Oran Es-Senia, 31100, Oran, Algerie, Email: jean-christian.bernede@univ-nantes.fr) : Effect of MoO₃ in the cathode buffer layer on the behaviour of layered organic solar cells. Indian J pure appl Phys 2014, 52(12), 829-38.

The behaviour of small-molecule organic solar cells based on copper-phthalocyanine/fullerene with different cathode buffer layer is investigated as a function of air exposure duration. The effect of MoO₃ on the properties of photovoltaic solar cells (OPVCs) when it is introduced in the cathode buffer layer (CBL), has been studied. Photovoltaic performances were measured as a function of time of air exposure. During the first days of air exposure, the efficiency of the OPVCs with MoO₃ in their CBL increases significantly, while it decreases immediately after air exposure in the case of reference OPVCs, i.e. without MoO₃ in the CBL. Nevertheless, the lifetime of the OPVCs with MoO₃ in their CBL is around 60 days, while it is only 10 days in the case of reference OPVCs. The initial increase of the OPVC with MoO₃ in their CBL is attributed to the slow decrease of the work function of MoO₃ due to progressive contamination. Then, the progressive degradation of the OPVCs efficiency is due to water vapour and oxygen contamination of the organic layers. The use of double CBL, Alq₃/MoO₃, allows to interrupt the growth of pinholes, defects and increases the path of permeating gas. Also it can prevent the contamination of the organic layer by Al. All this results in significant increase of the lifetime of the OPVCs.

9 illus, 3 tables, 32 ref