017135   Sundaraganesana N;Joshuab B D;Rajamoorthy M; Gangadhara C H (Physics Dep, Annamalai University, Annamalai Nagar-608 002) : FT-IR, FT-Raman spectra and ab-initio DFT vibrational analysis of 2-chloro-5-aminopyridine. Indian J pure appl Phys 2007, 45(12), 969-78.

The FT-IR and FT-Raman spectra of 2-chloro-5-aminopyridine (CAP) have been recorded in the region 4000-400 cm^-1 and 3500-100 cm-1, respectively. The optimized geometry, frequency and intensity of the vibrational bands of CAP were obtained by the ab- initio and DFT levels of theory with complete relaxation in the potential energy surface using 6-31G(d,p) and 6-311+G(2df,2p) basis sets. The harmonic vibrational frequencies were calculated and the scaled values have been compared with experimental FT-IR and FT-Raman spectra. A detailed interpretation of the vibrational spectra of this compound has been made on the basis of the calculated potential energy distribution (PED). The observed and the calculated frequencies are found to be in good agreement. The experimental spectra also coincide satisfactorily with those of theoretically constructed bar type spectrograms.

017134   Suman;Sharma N D (Physics Dep, Kurukshetra University, Kurukshetra-136 119) : Structural and magnetic properties of zinc ferrite aluminates synthesized by ceramic method. Indian J pure appl Phys 2007, 45(6), 549-54.

Mossbauer spectroscopy has been used to investigate the cation distribution in ZnAl_xFe_2-xO₄ spinel ferrites with the composition 0≤x≤1. All samples were prepared using the ceramic technique. A single phase formation of the compounds did not occur. It is confirmed by X-ray diffraction measurements. The variation in saturation magnetization of the samples at room temperature has been explained on the basis of site distributions and the strength of the exchange interactions between magnetic ions.

017133   Sudhakar Reddy B;Buddhudu S (Physics Dep, Sri Venkateswara University, Tirupati-517 502) : Emission spectra of Eu3<. Indian J pure appl Phys 2007, 45(6), 496-500.

The development and luminescence properties of (0.2 mol%) of Eu3⁺ and Tb3⁺ ions doped borophosphate oxyfluoride (BPOF) optical glasses have been reported in the following general compositions: 69.8 B₂O₃-10 P₂O₅-10 (ZnO/CdO/TeO₂)-10 (AlF₃/LiF) Measured emission spectra of Eu3⁺: BPOF optical glasses have revealed five emissions (⁵D₀→⁷F_0,1,2,3&4) at 580, 591, 613, 654 and 701 nm, respectively with λ_exci = 392 nm (⁷F₀→⁵L₆). In case of Tb3⁺:BPOF optical glasses, four emissions ⁵D₄→⁷F_6,5,4&3) that are located at 489, 545, 584 and 622 nm have been measured with λ_exci = 374 nm. For the red (Eu3⁺) and green (Tb3⁺) emission bands, decay curves have been recorded to compute their lifetimes. By using relevant energy level diagrams, emission processes in the glasses have been explained.

017132   Sudha G F;Senthil Kumaran G;Thirumoorthi J; Balamurugan K;Anand M (Electronics and Communication Engng Dep, Pondicherry Engng Coll, Pondicherry-605 014) : Optical monitoring of bilirubin-simulation and experimental results. J Optics 2007, 36(2), 87-97.

Optical methods are now gaining importance for noninvasive diagnosis of diseases. This paper is a report of a study carried out to investigate the potential of optics for monitoring cutaneous bilirubin in adults to detect hyperbilirubinemia. commonly called as jaundice. Studies have indicated that cutaneous bilirubin is an effective indicator of serum bilirubin. The spectral characteristics of bilirubin show that by subtracting the skin reflectance of the different skin components, the contribution of bilirubin can alone be found. A computational skin model based on Monte Carlo is simulated which predicts the reflectance behaviour of jaundiced skin. The simulation results are corroborated by experimental measurements taken on a test adult population.

10 illus, 2 tables, 20 ref

017131   Subhash Chander;Sharma M P;Krishnamurthy A; Srivastava B K (Physics Dep, University of Rajasthan, Jaipur-302 004) : Mossbauer study of nano-particles of spinel ferrites Li_xFe_3-xO₄. Indian J pure appl Phys 2007, 45(10), 816-20.

Mossbauer spectra have been recorded on three nano-particle samples in the series Li_xFe_3-xO₄ (for x = 0.1, 0.2 and 0.3) at 300K and 80K. Spectra could be resolved into two doublets attributed to two crystalline sites, viz., tetrahedral site and octahedral site. Li occupies the octahedral site with a complete preference as in the bulk particle size state. Analysis of Mossbauer spectra shows that electron hopping manifests at temperatures down to 80K implying the absence of a Verwey type transition. Magnetization measurements support this inference and are suggestive of no such transition occurring down to 20K.

017130   Srivastaa A;Singh V B (Physics Dep, Udai Pratap Autonomous College, Varanasi-221 002) : Theoretical and experimental studies of vibrational spectra of naphthalene and its cation. Indian J pure appl Phys 2007, 45(9), 714-20.

Raman and FTIR spectra of naphthalene and its cation have been systematically analyzed using ab-initio and density functional theory calculations. The optimized geometries, harmonic vibrational wave numbers and intensity of vibrational bands of naphthalene and its cation were calculated invoking different basis sets up to HF/6-311++G^** and B3LYP/6-311++G^** level. Vibrational assignments have been made and calculated DFT frequencies and intensities of the naphthalene and its cation at B3LYP/6-311++G^** levels and are found to be in better agreement with corresponding experimental values in comparison to previous results. The experimental and theoretical studies of neutral and ionized naphthalene have revealed an unexpected effect of the ionization on the vibrational spectra that lead to a dramatic reduction in intensities of CH stretching modes and concurrently large increase in the intensities of ring CC stretching and CH bending vibrations.

017129   Singhal S;Barthwal S K;Kailash Chandra (Chemistry Dep, Panjab University, Chandigarh, Email: chandfuc@iitr.ernet.in) : Cation distribution in the nano size aluminium substituted cobalt ferrites using XRD, magnetic and Mossbauer spectral studies. Indian J pure appl Phys 2007, 45(10), 821-5.

Aerosol route have been used to prepare the nano size ferrites CoFe₂O₄, CoAl_0.37Fe_1.63O₄, CoAl_0.95Fe_1.05O₄ and CoAl_1.36Fe_0.64O₄. A decrease in lattice parameter and saturation magnetization with the increase of aluminium concentration was attributed to the smaller ionic radius and weakening of exchange interactions respectively. Room temperature Mossbauer spectra of as obtained samples exhibited a broad doublet suggesting super paramagnetic nature. The samples annealed at 120°C showed broad sextets, which were fitted with different sextets, due to the tetrahedrally and octahedrally coordinated iron cation. The cation distribution calculated from the X-ray intensity and Mossbauer data indicated that Al₃₊ ions enter into A and B sites in <126>2 : 3 ratio and Fe³⁺(oct.)/Fe3+(tet.) ratio increases with Al³⁺ concentration.

017128   Singh M;Aghamkar P;Duhan S (Applied Physics Dep, Guru Jambheshwar University of Science & Technology, Hisar-125 001, Email: msgur_18@yahoo.com) : Nonlinear optical parameters of Raman scattered mode in weakly polar magnetized semiconductor-plasma. Indian J pure appl Phys 2007, 45(11), 893-9.

Presents an analytical investigation of nonlinear absorption coefficient and refractive index of the Raman scattered stokes mode resulting from the nonlinear interaction of an intense pumping light beam with molecular vibrations of semiconductor-plasma. The origin of this nonlinear interaction lies in the third-order (Raman) susceptibility arising from the induced current density and density fluctuations generated within the medium. The total refractive index and absorption coefficient are determined through the effective susceptibility derived with the help of coupled-mode theory of plasmas. The effect of Szigeti effective charge (q) and magnetic field (b0) has been introduced through equation of motion of lattice vibration and Lorentz force, respectively. The numerical estimates are made for n-type InSb crystal duly irradiated by a 10-nanosec pulsed 10.6 μm CO₂ laser. The Szigeti effective charge contributes the Raman susceptibility at moderate excitation intensity. At high excitation intensity, the contribution of Szigeti effective charge is wiped off and nonlinearity in the medium is only due to differential polarizability. In the absence of Szigeti effective charge, the magnitude of Raman susceptibility is found to agree with other theoretical quoted values. The analysis establishes that a small absorption coefficient and large refractive index can easily be obtained by proper selection of magnetic field and doping concentration under moderate excitation intensity in weakly polar semiconducting crystals which proves its potential as candidate material for the fabrication of cubic nonlinear devices.

017127   Shukla R K;Atul Kumar;Srivastava K;Yadav S (Chemistry Dep, V.S.S.D. College, Kanpur-208 002) : Comparative study of compressibilities of ternary liquid systems from two liquid state model at 298.15 K. Indian J pure appl Phys 2007, 45(9), 726-32.

Isothermal and adiabatic compressibility of three liquid ternary : toluene + cyclohexane + carbon tetrachloride, benzene + cyclohexane + toluene and carbon tetrachloride + cyclohexane + benzene and its nine contributory binaries were estimated using two liquid state models; Flory statistical theory (FST) and Bertrand-Acree-Bruchfield (BAB) over a wide range of composition. Excess compressibilities deduced from these models were also estimated in order to study the nature and extent of molecular interactions involved therein. The theoretical results so obtained from the two liquid state models have been compared.

017126   Sharma R K;Suwalka O P;Lakshmi N;Venugopalan K (Physics Dep, Mohanlal Sukhadia University, Udaipur-313 001) : Hyperfine fields in nano particles of Cr_0.25Co_0.25Zn_0.5Fe₂O₄. Indian J pure appl Phys 2007, 45(10), 830-3.

Nano particles of Cr substituted cobalt zinc ferrite (Cr_0.25Co_0.25Zn_0.5Fe₂O₄) were synthesized using chemical co-precipitation technique. Particles of average crystallite sizes varying from 5 to 23 nm were obtained by controlling the annealing temperature during preparation. Fe-57 M”ssbauer studies at room temperature showed that samples with particle sizes smaller than 10nm were superparamagnetic while those with bigger particle sizes showed the co-existence of a ferrimagnetic phase with a superparamagnetic one. M”ssbauer spectra recorded at 25 K for the smallest sized sample showed well defined sextets with hyperfine fields of 520 kOe and 484 kOe corresponding to the A and B sites.

017125   Sharma R K;Sharma Y K (Physics Dep, University of Rajasthan, Jaipur-302 004, Email: yksharma@uniraj.ernet.in) : <. Indian J pure appl Phys 2007, 45(10), 846-50.

⁵⁷Fe Mossbauer and X - ray powder diffraction (XRD) of the alloy system Fe_1-yCr_ySb₂ for 0≤y≤0.97 at 300K have been studied. XRD patterns of all specimens recorded using FeK_α radiation at 300K suggest the presence of single phase orthorhombic crystal structure for this alloy series. The lattice parameters and the unit cell volume increase with the increase in chromium concentration. The ⁵⁷Fe Mossbauer spectra for all the compositions analyzed as a single quadrupole split doublet reveal the paramagnetic character. The increase in the isomer shift and the decrease in the quadrupole splitting with the increase in chromium concentration γ for the alloy series have been correlated with the observed structural and bonding properties of the series compositions.

017124   Sharma N K;Indra C;Radjakumar T;Meenakshi G (Physics Dep, Kanchi Mamunivar Centre for Post Graduate Studies, Pondicherry 605 008) : Single injection in a spherical insulator in CDMM mode. Indian J pure appl Phys 2007, 45(8), 663-5.

The electrical behaviour of an insulator has been studied for a single injection (electrons) current flow containing significant density of thermally generated free carriers under density dependent mobility mode. The current injection in CDDM mode with spherical geometry has been further studied. In this problem, it is found that at low current injection, the pure Ohm's law for current-voltage characteristics has finally been converted into the half power law at high injection level under space charge regime.

017123   Sharma M P;Prashant B L;Krishnamurthy A; Srivastava B K (Physics Dep, University of Rajasthan, Jaipur-302 004) : Magnetization and Mossbauer studies of Ni_3-xCu_xFe alloys in nano-crystalline state. Indian J pure appl Phys 2007, 45(10), 842-5.

The iron-nickel alloys, commonly known as permalloys, known for atomic disorder, have been studied due to their interesting magnetic properties. Nano-particle samples have been prepared for three compositions in the series Ni_3-xCu_xFe.⁵⁷Fe Mossbauer studies are reported on the three nano-particle samples which are found to be ferromagnetic. The value of Tc goes down from 880K in Ni₃Fe to 800K in Ni₂CuFe. The introduction of Cu causes the saturation moment to decrease and lowering of temperature cause an increase in atomic disorder.

017122   Shankar A;Tanwar L S;Sirohi R S (Applied Phys Dep, Optical Engng, GJU&T, Hisar, Email: ajay_shankar@hotmail.com) : High resolution and low run-out errors in displacement measuring grating interferometer using natural interference zone. J Optics 2007, 36(3), 111-22.

In-plane displacement with high accuracy can be measured with a grating interferometer generating stable detector width compensated interference fringe pattern in natural overlap region. This is realized using a set of matched pitch gratings with array detector and Spatial Phase Measurement techniques has been used for retrieving in-plane displacement. This system shows good direct interpolation to realize comparable resolution and better tolerances in terms of run out error compared to most of the grating interferometers available in market or reported. It gives not only these advantages but also provide all opportunity to monitor and correct run out errors during the measurement process if on board image processing techniques are used besides data acquisition on a high speed personal computer.

10 illus, 1 table, 11 ref

017121   Semalty P D;Kapil Dev (Physics Dep, H N B Garhwal University Campus, Badshahithaul Tehri-Garhwal-249 199, Email: psemalty@sancharnet.in) : Calculation of lattice specific heat of bcc NbZr dilute alloy. Indian J pure appl Phys 2007, 45(8), 658-62.

The lattice specific heat at very low temperatures, using a perturbation model which includes the mass change and change in the nearest-neighbour force constants due to interaction between impurity and host atoms has been calculated. In addition to the local perturbation due to mass change and force-constant changes, the effect of volume change has also been taken into account. The calculated results have been compared with the experimental measurements and values of central and non-central force-constant changes have been obtained. The increase in lattice specific heat is explained on the basis of these force-constant changes. The possibility of occurrence of resonance and localized modes from the calculation of resonant denominator have been investigated.

017120   Sebastian V;Suwalka O P;Lakshmi N;Venugopalan K (Physics Dep, M L Sukhadia University, Udaipur-313 001, Email: nambakkat@yahoo.com) : Ferromagnetism at room temperature in ball-milled Al-1at.%Fe. Indian J pure appl Phys 2007, 45(10), 839-41.

Iron nano particles have been embedded in an aluminium matrix through high energy ball milling. The Mossbauer spectrum of the as-milled sample at room temperature shows the presence of a magnetic hyperfine sextet, a paramagnetic singlet and a quadrupole doublet with relative areas of nearly 78, 16 and 6%, respectively. The value of the hyperfine field for the sextet corresponds to that of α-Fe. The quadrupole component, which is indicative of formation of an Al-rich solid solution, is broad with a width of 0.73 mm/s indicating a distribution in the quadrupole fields. The value of the average splitting is 0.5mm/s and isomer shift (IS) equal to 0.49mm/s with respect to metallic iron. M-H measurements show that the unmilled system is non-magnetic while the milled system of 30 min is ferromagnetic and exhibits very soft magnetic properties. Unreacted Fe clusters embedded at the nano-crystalline Al grain boundaries seem to be responsible for the observed net magnetic moment

017119   Sathiaraj T S (Physics Dep, University of Botswana, P.B. 0022, Gaborone, Botawana, Email: sathiara@mopipi.ub.bw) : Solar selective properties of copper-aluminium composite films. Indian J pure appl Phys 2007, 45(7), 613-7.

Composite films of copper and aluminium were deposited by reactive direct current co-sputtering of copper and aluminium. The number of copper pieces was varied during deposition which made it possible to vary the composition of the films. In order to understand the optical behaviour of the coatings, the optical constants were determined by fitting model dielectric functions to the transmittance and the near normal reflectance spectra in the wavelength range 300-2500 nm. The thicknesses of the layers obtained by modeling were confirmed by surface profilometry. The XPS studies of the samples reveal that the number of copper pieces used during co-sputtering control the formation of copper oxide. Computer simulations on layers of Cu-Al composites on metallic substrate with anti-reflection coatings were carried out to optimize solar absorptance using the optical data from the model. Solar absorptance as high as 0.91 with anti-reflectance coating was obtained from the simulation.

017118   Sahoo S;Dutta K;Acharyya S;Sit S K (Physics Dep, Dr Meghnad Saha Institute of Technology, P.O. Debhog, Haldia, Dist Purba Medinipur-721 657, Email: swapansit@yahoo.co.in) : Dielectric relaxation of associated ternary liquid mixture from high frequency conductivity measurement of solution. Indian J pure appl Phys 2007, 45(6), 529-44.

Dielectric relaxations of two binary (jk) polar mixtures like N-methyl acetamide (NMA) and acetone (Ac) as well as dimethyl sulphoxide (DMSO) and acetone(Ac) dissolved in non-polar solvents (i) benzene and carbontetrachloride were studied at 25, 30, 35, 40 and 25°C temperatures, respectively for 0.0,0.3, 0.5, 0.7, and 1.0 mole fractions xj of acetone under 9.88 GHz and 9.174 GHz electric field from complex high frequency conductivity σ_ijk* =(σ_ijk' + jσ_ijk" ) measurement of the ternary solution. The relaxation times τ_jk's of the binary polar mixtures were estimated from the ratio of slopes of σ_ijk"- w_jk and σ_ijk' - w_jk curves at wjk→0 as well as the slopes of σ_ijk"-σ_ijk' linear equations of existing method [Murthy et al., Indian J Phys, 63B (1989) 491]. They are compared with the reported τ `s due to Gopalakrishna's method to indicate the validity of both the methods. The proposed method of ratio of slopes seems to be a better choice in which the polar - polar interactions are almost eliminated. The dipole moments μ<sub>jk</sub> 's for both the methods were calculated in terms of slopes β's of σ<sub>ijk</sub> - w<sub>jk</sub> curves at wjk→0 and dimensionless parameters b's and compared with the reported μ's. The variations of τ<sub>jk</sub>`s and μ_jk`s with x_j of acetone for (NMA+Ac) and (DMSO+Ac) mixture at an experimental temperature are explained on the basis of solute-solvent (monomer) and solute - solute (dimer) associations like μ_jk -T curve of (NMA+Ac) mixture. The theoretical dipole moments μ_theo's were measured from the available bond angles and bond moments of polar groups of the molecules. A little disagreement between measured μ_jk 's and reported μ 's may be due to inductive, mesomeric and electromeric effects of the polar groups of the molecules at different temperatures under high frequency electric field .The thermodynamic energy parameters like enthalpy of activation DHt, entropy of activation ΔSτ and free energy of activation ΔFτ of (NMA+Ac) mixture were estimated from slopes and intercepts of ln (τ_jkT) against 1/T curves for different x_j of acetone from Eyring's rate theory to know the molecular dynamics of the systems.

017117   Roy J N;Maiti A K;Mukhopadhyay S (Physics Dep, Coll of Engng & Management, Kolaghat, KTPP township, Midnapur-721 171) : Exploitation of nonlinear material based tree-net architecture in all optical demultiplexing scheme. J Optics 2007, 36(1), 1-7.

In the field of optical interconnecting network and in superfast photonic computing system, the tree architecture and optical nonlinear materials play significant roles. Nonlinear optical material may find important uses in optical switching. Optical switch using nonlinear material makes if possible for one optical signal to control and switch another optical signal through nonlinear interaction in a material. In this communication such materials have been exploited to design an optical tree-net architecture, which can be utilized for demultiplexing scheme in all-optical domain.

5 illus, 12 ref

017116   Ray D K;Himanshu A K;Sinha T P (Physics Dep, Bose Institute, 93/1, Acharya Prafulla Chandra Road, Kolkata-700 009) : Structural and low frequency dielectric studies of conducting polymer nanocomposites. Indian J pure appl Phys 2007, 45(8), 692-9.

The intrinsically conducting polymer (ICP), polyaniline (PANI) has been synthesized by chemical polymerization process with the help of water soluble support polymer poly (vinyl pyrrolidone) (PVP). The X-ray diffraction of synthesized PANI-PVP polymer reveals that the polymeric nanocomposites are partially crystalline with orthorhombic phase at room temperature. The morphology of these composite polymers has been studied by Transmission Electron Microscopy (TEM) and Scanning Electron Microscopy (SEM). The dielectric measurement of the sample is performed in the frequency range 100 Hz - 1MHz and temperature range 213-313 K. An analysis of real and imaginary parts of dielectric permittivity and the electric modulus indicate the polydispersive nature of relaxation time as confirmed by Cole-Cole plot of the complex permittivity. The frequency dependence of modulus spectra is found to obey an Arrhenius law with activation energy of 0.07 eV. The frequency dependent electrical data has been analyzed in the framework of the conductivity. These results elucidate that there is an increased coupling among the local dipolar motions (short range order localized motion).

017115   Ranjini K;Nabhiraj P Y;Das S K;Mallik C; Bhandari R K (NO, Variable Energy Cyclotron Centre, 1/AF, Bidhan Nagar, Kolkata-700 064, Email: ranjini@veccal.ernt.in) : Estimation of electron temperature in 14.45 GHz ECR ion source plasma by analysis of Bremsstrahlung spectra. Indian J pure appl Phys 2007, 45(12), 965-8.

Electron Cyclotron Resonance Ion Sources (ECRIS) are known to produce intense X-rays of the order of 100's of keV. Energy of electrons in the resonantly heated microwave plasma has been estimated by analyzing the Bremsstrahlung spectra obtained using a standard alkali halide (NaI [Ti]) crystal detector. Experiments were carried out on argon plasma discharge from high performance ECR ion source operating at 14.45 GHz. The dependency of X-ray emission with microwave power has been studied in the range 50-400 W. It is verified that maximum energy gained by electrons in ECR plasma follows a power law E_max α P^3/8. X-rays of more than 800 keV energy can be generated at very low microwave power as 400 W. The influence of magnetic field and gas pressure in the production of X-rays has also been analyzed.

017114   Randhawa B S;Gandotra K (Chemistry Dep, Guru Nanak Dev University, Amritsar-143 005) : Application of Mossbauer spectroscopy in thermal decomposition studies of some metal ferricarboxylates. Indian J pure appl Phys 2007, 45(10), 795-9.

The thermal decomposition of magnesium and calcium hexa(formato)ferrates(III), M₃[Fe(HCOO)₆]2xH₂O, has been carried out in flowing air atmosphere from ambient temperature to 700°C. Various physico-chemical techniques i.e. TG, DTG, DSC, XRD, IR, Mossbauer spectroscopy etc. have been employed to characterize the intermediates/end products. After dehydration, the anhydrous complexes undergo decomposition to yield an iron(II) oxalate intermediate in the temperature range 100-130°C. A subsequent oxidative decomposition of iron(II) species leads to the formation of α-Fe₂O₃ and respective alkaline earth metal carbonate/oxide in successive stages. Finally, nanosized ferrites of the stoichiometry, MgFe₂O₄ and Ca₂Fe₂O₅ have been obtained as a result of solid-state reaction between α-Fe₂O₃ and a fraction of MO. The obtention of ferrites at a temperature much lower than possible in conventional ceramic method, is a special feature of the method used.

017113   Ramprasad A V;Meenakshi M (Electronics and Communications Engng Dep, Coll of Engng - Anna Univ, Guindy, Chennai-25) : Performance measurement of various modulation formats in the presence of dispersion and non linear effects for WDM optical system. J Optics 2007, 36(2), 78-86.

Increase in the data rate of fiber optic communication system is limited due to dispersive and nonlinear effects of the fiber medium. In this paper for the first time to the author's knowledge we have estimated the optimal length of dispersive compensating fiber which is determined by varying the DCF length to obtain high Q factor for various input power levels. Also we have simulated 16 and 32 DWDM channels for the data rate of 40 Gb/s and determined the Q factor for various modulation formats for the non linear dispersive fiber.

7 illus, 6 tables, 17 ref

017112   Rajesh Kumar;Rajendra Prasad (Applied Physics Dep, Z H College of Engineering & Technology, Aligarh Muslim University, Aligarh-202 002) : Studies of the nano scale voids and free volume in <. Indian J pure appl Phys 2007, 45(9), 709-13.

The bombardment of the polymeric materials with Swift Heavy Ions (SHI) results in the change of their free volume properties which have strong correlation with macroscopic properties of the polymeric material. Positron Annihilation Lifetime Spectroscopy (PALS) provides direct information about the dimension, content and hole size distribution of free volume in polymers. Makrofol-N polycarbonate films (40 μm) were irradiated with ⁴⁰Ar ions of energy 14.9 MeV/n to the fluences of 10⁵ ions/cm² from UNILAC, GSI Darmstadt, Germany. The effect of ion irradiation on free volume and characterization by Positron Annihilation Lifetime Spectroscopy (PALS) has been studied. Observed lifetime spectra were resolved into three components and o-Ps lifetime component was associated with the pick off annihilation of positronium trapped by the free volume. The o-Ps lifetime and the average free volume are found to increase on irradiation.

017111   Rajesh Kumar;Mahur A K;Jojo P J;Rajendra Prasad (Applied Physics Dep, Z H College of Engineering & Technology, Aligarh Muslim University, Aligarh-202 002) : Study of radon and its progeny levels dwellings of Thankassery, Kerala. Indian J pure appl Phys 2007, 45(11), 877-9.

Radon monitoring has become a global phenomenon due to its health hazard effects on population. ²²²Rn and its radioactive daughters present in the environment results into the largest contribution to the average effective natural radiation dose received by human beings. Indoor ²²²Rn exposure to the population depends in a complex way on the characteristics of the soil, the building structure, meteorology, ventilation conditions and occupants behaviour. LR-115 type II Solid State Nuclear Track Detectors (SSNTDs) have been used for the measurements of indoor radon concentration in 24 rooms in some in dwellings situated in Thankassery town along the south west coast of Kerala to carry out the assessment of the variability of expected radiation exposure of the population due to radon and its progeny. The town is situated near the high background area of Kerala. Radon concentrations are found to vary from 44.3 to 373.3 Bqm^-3 with an average of (144.7±61.5) Bqm-3 whereas the annual effective dose equivalents vary from 1.7 to 14.2 mSv with an average of (5.5±2.3) mSv.

017110   Quamara J K;Sridharbabu Y;Goyal G;Sharma A (Applied Physics Dep, National Institute of Technology, Kurukshetra-136 119) : Electrical conduction behaviour of pristine and 100 MeV Ni ion irradiated PET/0.8PHB polymer liquid crystals. Indian J pure appl Phys 2007, 45(11), 910-9.

Electrical conduction behaviour of pristine and 100 MeV Ni ion irradiated terephthalate (PET)/0.8 poly(p-hydroxy-benzoic acid) (PHB) polymer liquid crystals has been investigated in transient and steady state conditions at different electric fields (13-104.3 kV/cm) and temperatures (40-250°C). The various mechanisms responsible for charge transport phenomena can be thoroughly investigated by studying temperature and field dependent conduction behaviour. The origin of transient currents in polymers has been ascribed to number of mechanisms. The dipolar relaxation seems to be the major contributor to these currents at lower temperatures. The temporal decay of current may be due to trapping of charge carriers and/or due to the reduction of electric field owing to the formation of Schottky layers in the vicinity of the electrodes. The high temperature relaxations do not contribute much to the transient behaviour. The transient currents in ion irradiated samples are mainly governed by cross-link structures and free radical formation in addition to the d-transition. Poole-Frenkel and Schottky conduction mechanisms appear to operate at high and low temperature regions, respectively, for both pristine and irradiated samples.

017109   Prabakar K;Mallikarjun Rao S P (Acoustic Emission Lab, Physics Dep, University College of Science, Osmania University, Hyderabad-500 007, Email: spmrao@yahoo.com) : Pattern recognition analysis of acoustic emission signals propagated through a waveguide - a simulation study. Indian J pure appl Phys 2007, 45(11), 900-5.

Pattern recognition (PR) analysis of acoustic emission (AE) signals for classifying the source mechanisms involved, is a widely accepted practice, if the signals are directly picked up from the test specimen. However, there is an apprehension for the same, when a waveguide (WG) is used to pickup the signals. In the present paper, the validity of PR analysis has been studied on burst AE signals even after their propagation through a WG, using a software routine for wave propagation in cylindrical rods, based on Pochhammer-Chree (PC) equations, developed by Seco F et al. "PCDISP: a tool for the simulation of wave propagation in cylindrical waveguides", In: The 9th international congress on sound and vibration, in Orlando, Florida (2002). It is found that irrespective of the dimensions of the cylindrical WG, PR analysis can classify different source mechanisms. An experiment to support the simulation is also included.

017108   Perumal Sankar S;Sundaravadivelu S (ECE Dep, Jayamatha Engng Coll, Aralvoimozhi, Kanyakumari District, Tamilnadu, Email: spsankar2004@yahoo.co.in) : High reflectance optical thin film grating light valve. J Optics 2007, 36(3), 145-52.

Micro-Electro-Mechanical-Systems (MEMS) is a technology that has made remarkable progress during the past ten years. Application of MEMS in optical systems, which is known as optical MEMS, has initiated the new category of MOEMS (Micro-Optoª-Electro-Mechanical-Systems) enabled us to combine the mechanical, electrical and optical components in very small scale. The significant impact of MOEMS in display technology has resulted in a well controlled diffractive optical display device called Crating Light Valve (CLV). This is a programmable diffraction phase grating, that operates on the electrostatic deflection of micro beams formed of moving parts on the surface of a silicon chip. Each CLV element consists of (typically) six dual-supported parallel ribbons fanned of silicon nitride (Si₃N₄) and coated with a reflective very thin top layer of aluminium. The optical efficiency of the CLV device is the product of diffraction efficiency, fill factor efficiency and the reflectivity of the top layer. The overall device efficiency is about 70, corresponding to an insertion loss of about I.5dB. Reflectivity of the top layer depends on the choice of material selected. This paper presents approaches to achieve high reflective Crating Light Valve. In visible spectral regions, a dielectric multilayer can be used to enhance the reflectivity based on the optical interference effect in Crating Light Valve. In our paper aluminium is used as a metal sub-layer. By coating a dielectric stack over this layer will further enhance the reflectivity of the device over a wide range of wavelengths. Here, the stack comprises of low and a high reflective layer of low and high refractive index materials SiO₂ and HfO₂ respectively. The effect is found to be much better than conventional method of sealing in a dry nitrogen environment.

6 illus, 13 ref

017107   Patil S D;Takale M V;Navare S T;Fulari V J; Dongare M B (Div of Theoretical Phys, Phys Dep, Shivaji Univ, Kolhapur-416 004) : Analytical study of HChG-laser beam propagation in collisional and collisionless plasmas. J Optics 2007, 36(3), 136-44.

Studies the propagation of m=0, 1 and 2 mode Hermite-cosh-Gaussian (HChG) laser beams in collisional and collisionless plasmas. The field distribution in the medium is expressed in terms of beam-width parameter f and decentred parameter b. The differential equations for f-parameter are established by parabolic wave equation approach under paraxial approximation. Analytical solutions are obtained under the condition R_n <60> R_d where, R_n is the self-focusing length and R_d is the diffraction length. The behaviour of f-parameter with the dimensionless distance of propagation η for various b-values is examined by numerical estimates. The results are presented graphically.

2 illus, 26 ref

017106   Patel K;Vaidya R;Patel S G (Physics Dep, Sardar Patel University, Vallabh Vidyanagar-388 120, Email: shantibhaip@yahoo.com) : Microstructural analysis of zirconium triselenide single crystals. Indian J pure appl Phys 2007, 45(6), 514-16.

The zirconium triselenide (ZrSe₃) single crystal has been grown by chemical vapour transport technique using iodine as a transporting agent. The optimum condition for the growth of this crystal is given. The stoichiometry of the grown crystals was confirmed on the basis of energy disperse analysis by X-ray (EDAX) and remaining structural characterization was accomplished by X- ray diffraction (XRD) studies. The lattice parameters obtained from the XRD analysis were a= 5.45 Å, b=3.74 Å and c=9.44 Å. This crystal is found to possess monoclinic, layered structure. The X-ray density was found to be 5.63 g/cc and volume was calculated about 193.50 Å3. The optical band gap of the as-grown crystal has been carried out with the help of optical absorption spectra in the range 700 - 1400 nm.

017105   Palanivel R;Velraj G (Physics Dep, Annamalai University, Annamalainagar-608 002) : FTIR and FT-Raman spectroscopic studies of fired clay artifacts recently excavated in Tamilnadu, India. Indian J pure appl Phys 2007, 45(6), 501-8.

The spectroscopic techniques represent one of the most powerful tools to investigate the structure of all the materials and chemical composition of the cultural objects like potteries, tiles and ceramics. The spectroscopic techniques that have been used in the present study are FTIR absorption and Raman scattering spectroscopy. The potteries maintain aesthetic characteristics so that this type of artifacts can be considered very specific trace of every civilization. Therefore, it is of great importance to acquire knowledge about the chemical composition and the manufacturing techniques of an artifact. From the behaviour of the absorption bands and their corresponding Raman shifts in specific regions and their intensity showing the presence of minerals, traces of elements in the clay, the knowledge of the artisans and the conditions of the temperature control to make qualitatively good materials of archaeological artifacts. The temperature of firing and the vitrification stage are also being established in the case of potteries from the recent excavations at Maligaimedu, Thiruverkadu and Palur in Tamilnadu, India.

017104   Pal B;Singh J;Pawan Singh;Chaturvedi D K (Physics Dep, DCR University of Science & Tech, Murthal-131 039) : Electronic structure and electric field gradient calculations for H<. Indian J pure appl Phys 2007, 45(12), 950-8.

The electronic structure and electric field gradient (EFG) for H⁺ and μ⁺ in simple metals have been investigated. H⁺ and μ⁺ occupy octahedral site in fcc metals. The EFG arises due to the valence and size differences between impurity and host atoms. The former contribution has been evaluated using the impurity induced charge density calculated self-consistently using the spherical solid model potential for discrete lattice and Blatt's correction for lattice dilation. The latter contribution has been evaluated in the elastic continuum model considering the dressed point ions interacting through screened Coulomb potential. The scattering phase shifts, impurity potential, induced charge density and EFG have been calculated. The phase shifts are found to be slowly converging and these are more prominent in Al than in Cu. Both the valence and size effect EFGs are found cylindrically symmetric yielding the asymmetry parameter (η) to be zero. The size effect EFG is found to be dominating at both the first and second nearest neighbours.

017103   Naik V M;Naik R;Haddad D B;Thakur J S;Auner G W;Lu H;Schaff W J (Natural Sciences Dep, Michigan-Dearborn Univ, Dearborn, MI 48128, Email: vmnaik@umich.edu) : Raman Scattering and Photoluminescence in InN semiconductor Films. Asian Chem Lett 2006, 10(1-2), 77-82.

The optical absorption, photoluminescence (PL) and Raman scattering of InN semiconductor films differing in carier concentration by three orders in magnitude have been investigated. The film grown by molecular beam epitaxy (MBE) has a low carrier concentration (n_e = 3.5 x 10¹⁷ cm^-3) and shows a bandgap energy (E_g) of <126>0.6 eV whereas the InN film grown by Plasma Source Molecular Beam Epitaxy (PSMBE) is highly degenerate (n_e = 9.6 x 10²⁰ cm^-3) and shows E_g <126>1.9 eV. Raman scattering and the x-ray diffraction results are consistent with the structural quality of these films. A very strong PL emission at <126>1.8 eV is detected in the highly degenerate film consistent with the optical absorption data. The higher values E_g determined by optical absorption techniques in this highly degenerate InN has been explained as being due to the conduction band filling effects caused by high free carrier concentration.

4 illus, 18 ref

017102   Mukherjee A;Rahman M;Bhattacharyya S S; Chaudhuri B K (Solid State Physics Dep, Indian Association for the Cultivation of Science, Kolkata-700 032) : Measurement of some physical parameters of deformed helix ferroelectric liquid crystal with an antiferroelectric phase. Indian J pure appl Phys 2007, 45(8), 674-8.

Temperature dependent static dielectric constant of a deformed helix ferroelectric liquid crystal (DHFLC) material MOPBIC with antiferroelectric (AF) phase having very high value of spontaneous polarization (Ps) and ultra short pitch have been measured for two different cell thickness. The static dielectric constant (F128><101>') of this material is found to be extremely large and increases with increasing cell thickness. The behaviour of electrical switching time, optical response time and rotational viscosity has also been measured as a function of temperature showing very fast response time over a broad temperature range. Besides tristable switching property in the AF phase, additional advantages like high response speed in electro optic effects and low threshold voltage corresponding to their large spontaneous polarization demand great technological implications of this type of liquid crystals.

017101   Mehra R;Pancholi M (Pure & Applied Chemistry Dep, M D S University, Ajmer-305 009) : Study of molecular interactions in binary mixtures of benzene-butanol and toluene-butanol systems from acoustic and thermodynamic parameters. Indian J pure appl Phys 2007, 45(7), 580-90.

Measurments of viscosity and density in conjunction with sound speed have been used for evaluating derived parameters for the binary system of benzene-butanol and toluene-butanol in the temperature range 298-318 K at an interval of 10 K. From these, excess parameters have been calculated. The variation of derived parameters as well as the sign and magnitude of corresponding excess functions has been used to investigate the type and extent of interactions between the component molecules of the binary liquid mixtures. The validity of various theoretical approaches of liquids has been tested for the system by comparing theoretical sound speeds with those experimentally determined over the entire composition range in the temperatures range 298-318K.

017100   Manoharan C;Venkatachalapathy R;Dhanapandian S;Deenadayalan K (Physics Dep, Annamalai University, Annamalainagar-608 002) : FTIR and Mossbauer spectroscopy applied to study of archaeological artefacts from Maligaimedu, Tamil Nadu, India. Indian J pure appl Phys 2007, 45(10), 860-5.

Archaeological potteries belonging to 300 BC collected from Maligaimedu (11°48'Lat.N; 79°35'Long.E) Tamil Nadu, India were subjected to FTIR, XRD and M”ssbauer spectroscopic studies in order to characterise the clay minerals associated, their origin and technology of firing adopted by artisans. To determine the firing temperature of the potteries and to find any phase change in magnetic minerals, the pottery samples were refired to different temperatures. From FTIR studies, it is observed that these pottery samples were made up of disordered kaolinite type clay with appreciable amount of iron with a firing temperature of about 800°C. The minerals like quartz, anorthite, orthoclase and hematite were identified using XRD. No change in the Mossbauer parameters are observed in the case of sample MGM-2 during laboratory firing up to 800°C, which indicates that original firing temperature is above 800°C. Changes in the Mossbauer spectra of sample MGM-5 during laboratory firing reveal that the laboratory firing atmosphere differs from original firing atmosphere. The presence of Fe2+ ion in as-received state spectra of black pottery (MGM-5) indicates that the sample was fired under reduced atmospheric condition during manufacturing. The colour of the potteries also reflects the above results.

017099   Manjeet Singh;Aghamkar P;Sen P K (Applied Physics Dep, Guru Jambheshwar University of Science & Technology, Hisar-125 001, Email: msgur_18@yahoo.com) : Effect of doping on stimulated Brillouin scattering in piezoelectric magnetized III-V semiconductors. Indian J pure appl Phys 2007, 45(6), 517-23.

Using the hydrodynamic model of a semiconductor-plasma and following the coupled mode approach, an analytical investigation has been made for stimulated Brillouin scattering (SBS) resulting from the nonlinear interaction of an intense pump beam with acoustic perturbations internally generated due to piezoelectric and electrostrictive property of the crystal. The analysis deals with the qualitative behaviour of threshold pump electric field for the onset of SBS and resulting gain coefficient with respect to doping concentration (through plasma frequency) in piezoelectric III-V semiconductors subjected to transverse magnetostatic field. The numerical estimates are made for n-type InSb crystal at 77 K duly shined by pulsed 10.6 μm CO₂ laser. The threshold value of pump field required for the onset of SBS is found to lower in the presence of magnetostatic field. At resonance, the Brillouin gain is two hundred and 10⁴ times in the presence of piezoelectricity and magnetostatic field, respectively, than in their absence. Moreover, the SBS gain coefficient increases with increasing in scattering angle and results in maximum value for the backscattered mode. The backward Brillouin gain is found to be 10⁴ times larger than the forward gain. The analysis also suggests the possibility of observing phase conjugation reflectivity as high as <126>10⁶ in weakly piezoelectric doped III-V semiconductors subjected to a magnetic field.

017098   Mangal R K;Tripathi B;Singh M;Vijay Y K;Rais A (Physics Dep, University of Rajasthan, Jaipur-302 004) : Growth and characterization of In-Sb thin film structure. Indian J pure appl Phys 2007, 45(12), 987-90.

Thin films of InSb have been obtained by resistive heating method at the pressure 10^-5 torr. Mixing of these bilayers has been done by rapid thermal annealing as well as vacuum annealing process. Characterizations of these films have carried out by optical band gap, Rutherford backscattering and X-ray diffraction studies. Obtained results indicate formation of InSb semiconductor.

017097   Mandal P;Mukhopadhyay S (Phys & Technophys Dep, Vidyasagar Univ, Midnapore-721 102) : New approach of long distance all-optical switching mechanism by interaction between two Gaussian pulses in transverse mode propagated through an optical waveguide. J Optics 2007, 36(1), 22-30.

Proposed an analytical model of phase sensitive transverse interaction between two orthogonally polarized Gaussian pusles. To realize it author considered a Gaussian pulse propagating through an electro optic modulator. Using polarizer It was first decompose into two linearly orthogonal polarized waves. Then the orthogonal components of the pulses move through the optical fiber. By controlling the applied voltage across the modulator and controlling the ratio of length to width of the modulator it can change the phase relation between the pulses. With the method a switching at a very long distance can be organized in the optical fiber.

1 illus, 1 table, 13 ref

017096   Kumar P;Pal S;Gautam S;Chaturvedi P;Verma P; Rawat J S B S;Harsh;Ghosal P;Bhatnagar P K (NO, Solid State Physics Lab, Lucknow Road, Delhi-110 054) : Plasma enhanced vapour deposition grown cold cathode emits high current density. Indian J pure appl Phys 2007, 45(11), 906-9.

The high aspect ratio of the carbon nanotube (CNT) (of the order of 10,000) coupled with novel electrical, mechanical and thermal properties of the CNT make them very attractive candidate for cold cathode application in high power vacuum devices. Such CNT based cold cathode (CCC) can provide large and stable emission current densities at reasonably low field and can be switched on and off instantaneously with no limitation on grid modulation. These CCC based vacuum devices can also be efficiently operated under harsh ambient conditions and therefore, ideally suited for air borne and space applications. In this paper, the development of CCC using vertically aligned matrix of carbon nanotubes with optimum tip density grown by chemical vapour deposition (CVD) and plasma enhanced vapour deposition (PECVD) technique on silicon substrate has been reported. The field emission characteristics of a typical CCC grown via CVD and PECVD were compared. The field emission current density obtained in case of CVD sample was 8 mA/cm² at a field of 3.6 V/F128><109>m while it was 35 mA/cm² at the same field in case of PECVD grown CCC. The emission current in most of the samples was found to be stable over long period of time. The measurements suggest great promise for achieving high current densities at practical electric fields.

017095   Khurana M S;Kamlesh Kumari; (Physics Dep, Indian Institute of Technology, Roorkee-247 667) : Quantum Monte-Carlo simulation study of attractive Hubbard chain. Indian J pure appl Phys 2007, 45(8), 679-86.

Quantum Monte-Carlo simulations of one-dimensional narrow band systems with attractive interactions (U <60>0) have been reported. Using Hubbard model, local squared magnetic moments, probability of double occupancy, spin magnetic susceptibility and various spin pairing correlation functions as a function of Coulomb interactions for different band fillings have been studied.

017094   Khattab K;Khamis I (NO, Atomic Energy commission, P.O. Box 6091, Damascus, Syria) : Sensitivity analysis of reflector types and impurities in 10 MW MTR type nuclear research reactor. Indian J pure appl Phys 2007, 45(6), 491-5.

The 2-D and 3-D neutronics models for 10 MW nuclear research reactor of MTR type have been developed and presented. Our results agree very well with the results of seven countries mentioned in the IAEA-TECDOC-233. To study the effect of reflector types on the reactor effective multiplication factor, five types of reflectors such as pure beryllium, beryllium, heavy water, carbon and water are selected for this study. The pure beryllium is found to be the most efficient reflector in this group. The effect of the most important impurities, which exist on the beryllium reflector such as iron, silicon and aluminium on the reactor multiplication factor, have been analyzed as well. It is found that the iron impurity affects the reactor multiplication factor the most compared to silicon and aluminium impurities.

017093   Khanna K M;Karap Kirui M S;Sakwa T W;Torongey P K;Ayodo K Y;Rotich S (Physics Dep, Moi University, P O Box 3900, Eldoret, Kenya) : Specific heat jump in anisotropic YBa₂Cu₃0_7-δ superconductor. Indian J pure appl Phys 2007, 45(12), 991-3.

Using the exotic pairing model, the jump in the specific heat DC/Tc in YBa₂Cu₃0_7-δ, for both breathing mode and buckling mode has been calculated. Its value was compared with the experimental values and it has been found that the specific heat jump in superconductor and the density of states were one fifth of the earlier reported values. This is indicative of the small fraction of carriers close to the Fermi level, which are paired and exotic pairing due to anharmonic perturbation of the apical oxygen ions leads to a lowering of DC/Tc.

017092   Kanwar A;Gupta Sureshchandra J (Phys Dep, VES Coll of Arts, Sci and Com, Sindhi Society, Chembur, Mumbai-71) : Study of PDCLC materials using fabry perot scattering technique. J Optics 2007, 36(1), 31-7.

Polymer dispersed cholesteric liquid crystals (PDCLCs) consist of liquid crystal (nematic and Cholesteric) droplets that are dispersed in a solid polymer matrix. PDCLCs are a relatively new class of materials that hold promise for many applications ranging from switchable windows to projection displays. These materials, which are simply a combined application of polymers and liquid crystals, are the focus of extensive research in the display industry. Cholesteric liquid crystasls are often considered to exhibit a modified nematic phase, the molecules they contain being parallel, but characterized by a continual rotation of the direction of molecular alignment (Director). This unusual twisting often causes the appearance of bright colors when cholesteric liquid crystals diffract light [1]. The mixtures of PDCLCs with room temperature nematic liquid crystal TL205 doped with Cholesteryl materials having different liquid crystal concentrations and polymer PN393 were investigated. The concentration of cholesteric liquid crystal played crucial role in the properties of PDCLCs. The phase transition temperatures (PITs) of the samples thus prepared were studied using Fabry Parot scattering studies (FPSS), Optical Polarising Microscope (OPM) and Differential Thermal Analysis (DTA).

4 illus, 2 tables, 17 ref

017091   Kannappan A N;Palani R (Physics Dep, Distance Education Wing, Annamalai University, annamalainagar-608 002) : Acoustical behaviour of glycerine, dextrose and sucrose in Na₂CO₃ and NaHCO₃ buffer solution. Indian J pure appl Phys 2007, 45(7), 573-9.

The ultrasonic velocity, density and viscosity of glycerine, dextrose and sucrose in sodium carbonate (0.5 M) + sodium bicarbonate (0.5 M) buffer solutions at temperatures 303, 308 and 313 K have been measured. The derived acoustical and thermodynamic parameters namely, adiabatic compressibility, free length, specific acoustic impedance, free volume, internal pressure, molar cohesive energy, viscous relaxation time, Gibb's free energy, relative association, available volume, molal hydration number and Lennard Jones potential have been calculated. The variations of these parameters with respect to the molarity and elevation of temperature have been explained on the basis of solute-solvent interaction and structure forming tendency of the solutes in the solvents.

017090   Kalra N;Chaturvedi D K;Suahil Kumar;Arora S (Physics Dep, Kurukshetra University, Kurukshetra-136 119, Email: dhiraj_chaturvedi@yahoo.co.in) : Electrical and optical studies of corona poled 4-hydroxy-4'-nitroazobenzene doped polymethylmethacrylate films. Indian J pure appl Phys 2007, 45(7), 618-23.

Guest-host polymeric systems with 4-hydroxy-4'-nitroazobenzene as guest and polymethylmethacrylate (PMMA) as host have been prepared by taking different concentrations of the guest and characterized by observing their electrical and optical behaviour. The prepared guest-host system has been found to have large band gap <126>2.86 eV and transmission over visible range. Pure polymer (PMMA) was not found to show any observable electrical non-linearity whereas mixing of dye (guest) has shown remarkable effect on its non-linear electrical behaviour. Moreover, the model guest-host blend (4-hydroxy-4'-nitroazobenzene/PMMA) has been found to exhibit desired order of non-linearity by optimizing the concentration of guest, poling current and poling temperature.

017089   Harish Kumar;Kaler R S;Kamal T S (Electronics & Communication Engng Dep, Sant Longowal Inst of Engng & Technol, Longowal-148 106, District Sangrur, Punjab, Email: harishk76@yahoo.com) : Performance analysis of four wave mixing using volterra series method with higher-order dispersion effects. J Optics 2007, 36(1), 38-50.

The intensity fluctuations due to FWM in the presence of higher-order dispersion effects using Volterra Series Transfer Function method have been investigated. The impact of FWM on the hannel Spacing, Transmission Distance and Frequency has been studied in the presense of higher-order dispersion terms. It has been found that at frequency 50 THz with first-order dispersion compensation, the intensity fluctuation have been reduced to 0.009 mW from 0.155 mW and this can be further improved with first- and second-order dispersion compensation together to. 00002 mW. Also it have been found for intensity fluctuations 0.25 mW, the transmission distance can be enhanced from 120 Km to 620 Km with first-order dispersion compensation and this can be further enhanced to 810 Km with first- and second-order dispersion compensation together. It has also been observed that the second- and third-order dispersion effects are very small, when the first-order dispersion is present.

5 illus, 11 ref

017088   Gunasekaran S;Thilak Kumar R;Ponnusamy S (PG & Research Department of Physics, Pachaiyappa's College, Chennai-600 030, Email: manojthilak @yahoo.com) : Vibrational spectra and normal coordinate analysis of adrenaline and dopamine. Indian J pure appl Phys 2007, 45(11), 884-92.

The FTIR and FTRaman spectra for adrenaline and dopamine have been recorded over the region 4000-400 cm^-1 and 3500-50 cm^-1. Both adrenaline and dopamine molecules belong to the Cs point group. A generalised set of symmetry coordinates has been constructed and hence, potential constants have been evaluated using Wilson's F-G matrix method. Potential energy distribution has also been calculated for the normal modes of vibration to check whether the chosen set of vibrational frequencies contribute maximum to the potential energy associated with the normal coordinates of the molecule.

017087   Goyal S;Nishchal N K;Beri V K;Gupta A K (Photonics Div, Instruments Research & Development Establishment, Raipur Road, Dehradun-248 008, Email: akgupta@irde.res.in) : Complex data mapping on a binary ferroelectric liquid crystal electrically addressed spatial light modulator for target recognition. Indian J pure appl Phys 2007, 45(8), 647-53.

For displaying a complex valued function onto a binary amplitude-only or phase-only spatial light modulator, an encoding technique is required. Implements an encoding scheme proposed by Davis et al. [Appl Opt, 42 (2003) 2003] for optical processing the complex product function in the hybrid digital-optical correlator. The output of this correlator consists of two autocorrelation peaks along with a strong dc. Out of these three terms, our interest is in capturing only one of the correlation peaks, while discarding the other correlation peak and strong dc. For capturing only one of the correlation peaks, multiplies a chirp function with the rotation-invariant maximum average correlation height filter. The product function, that is basically a multiplied product of the input scene's Fourier spectrum and the chirp-encoded filter, is inverse Fourier transformed to obtain the correlation peaks. Due to chirp encoding, the correlation signals are focused in three different planes. Thus, placing peak capturing CCD camera at a particular plane we can capture only one autocorrelation peak. Results with almost similar tank images having different energy values have also been shown.

017086   Ghosh D;Lahiri M B;Datta I S (Nuclear and Particle Physics Research Centre, Physics Dep, Jadavpur University, Kolkata-700 032) : Two-dimensional void probability scaling of grey tracks emitted in 24 Mg-AgBr interaction at 4.5 AGeV/c. Indian J pure appl Phys 2007, 45(8), 637-40.

Presents a very rigorous study of two-dimensional void probability scaling of medium energy target protons emitted in 24Mg-AgBr interaction at 4.5 AGeV/c in terms of their emission angle (q ) and azimuthal angle f.The study indicates that the two-dimensional void probability scaling holds good for the total region of phase space.