bluuebunny/crossref_metadata_2025 huggingface dataset:
Performance evaluation of a buried steel pipe in a moving slope: a case study
Authors: Chan P DS , Wong R CK
Published: October 2004

Shallow and deep-seated soil movements were observed in a slope in which a steel pipe was laid for transport of oil emulsion. In the past, solutions have been developed mainly for analysis of buried pipes subjected to longitudinal or transverse soil movement at a shallow depth. Based on simplified soilpipe interaction relationships and ground movement patterns, this paper presents methods for analysis of pipes subjected to the measured soil movements at varying depths in slopes. These methods decompose the resultant soil movement into its components parallel and perpendicular to the pipeline, i.e., the pipeline is subjected to a combined longitudinal and transverse soil movement. In the transverse movement analysis, the effect of pipe stretching due to large deformation is included. These methods were used in the case study to assess the potential of yielding in the pipe with the given soil movements that occurred in the slope.Key words: pipeline, soil subgrade, soil movement, bending, axial stretching.
Instability of dykes at Seven Sisters Generating Station
Authors: Garinger Blair , Alfaro Marolo , Graham James , Dubois Denis , Man Alex
Published: October 2004

Water-retention dykes at Seven Sisters Generating Station in Manitoba have experienced irregular instabilities since they were heightened in the late 1940s. An investigation was undertaken to compare three locations at the site, one section of dyke that had experienced previous instability, a second section that had remained stable, and a third, background location that had not experienced dyke loading. The investigation included laboratory tests, field tests, and computer modelling. The laboratory tests indicated anisotropic stiffness and brittle strain-softening behaviour in the highly plastic clay beneath the dykes. Results from the stable and unstable sections showed greater brittleness and anisotropy at the unstable section. Pore fluid chemistry tests for cation and anion concentrations showed considerable reductions in concentrations of calcium and sulphate beneath the dykes compared with those of the background section. This suggested leaching of gypsum in the foundation soil. Computer modelling was done using seepage, stressdeformation, and slope stability software. Results indicated that the stable and unstable sections both had safety factors greater than unity if "post-peak" strengths were used. Both were close to unity if residual strengths were used. The results suggest that time- and location-dependent depletion of gypsum cementation bonds caused by seepage beneath the dykes has increased the brittleness and anisotropy and reduced stability with time.Key words: clay, cementation, gypsum, leaching, anisotropy, brittleness.
Measurement of wave velocities and attenuation using an ultrasonic test system
Authors: Leong Eng-Choon , Yeo Sir-Hoon , Rahardjo Harianto
Published: October 2004

The use of ultrasonic testing to determine pulse velocities and small-strain elastic constants for rocks has been standardized in American Society for Testing and Materials (ASTM) standard D2845-95. However, the use of ultrasonic testing to determine pulse velocities and small-strain elastic constants of soils is less common, as soils have higher damping characteristics which result in measurement difficulty. The signal transmitted through soil is weak and very noisy. As a result, the signal must be properly processed to provide a reliable estimate of the wave travel time. In this paper, an ultrasonic test system consisting of compression and shear wave transducers, a pulser, and a data-acquisition system is evaluated for measurement of both compression and shear wave velocities. Among the specimens tested were fully saturated and unsaturated soil specimens. The effects of acoustic coupling and signal processing on the transmitted pulse were investigated. The strain levels associated with the determination of the wave velocities were also measured. Furthermore, a method for determining attenuation characteristics for soil specimens from the frequency spectra is suggested.Key words: laboratory, compression wave, shear wave, velocity, attenuation, ultrasonic.
Factors affecting drying and wetting soil-water characteristic curves of sandy soils
Authors: Yang Hong , Rahardjo Harianto , Leong Eng-Choon , Fredlund D G
Published: October 2004

Drying and wetting soil-water characteristic curves (SWCCs) for five sandy soils are investigated using a Tempe pressure cell and capillary rise open tube. The test data are fitted to two SWCC equations using a least-squares algorithm. The obtained fitting parameters and some hysteretic behaviour are discussed and correlated with grain-size distribution parameters. A concept of total hysteresis is proposed to quantify the hysteresis of SWCC. The measured SWCC for one soil is also compared with the SWCC estimated from its grain-size distribution. The SWCC was also obtained at a high dry density for one of the soils. The results show that the shapes of the SWCCs are similar to the grain-size distributions of the soils and are affected by the dry density of the soil. A coarse-grained soil has a lower air-entry value, residual matric suction, and water-entry value and less total hysteresis than a fine-grained soil. The residual matric suction and water-entry value tend to approach the same value when the effective grain size D10of the soil is small, in the range of 3-6 mm. SWCCs of uniform soils have steeper slopes and less total hysteresis than those of less uniform soils. Soils with a low dry density have a lower air-entry value and residual matric suction than soils with a high dry density. The SWCC predicted from grain-size distribution is found to be sufficiently accurate.Key words: soil-water characteristic curve, water content, suction, hysteresis, grain size.
Melbourne's Southbank Interchange: a permanent excavation in compressible clay
Authors: Ervin Maxwell C , Benson Neil D , Morgan Jack R , Pavlovic Nick
Published: October 2004

The Southbank Interchange of the Melbourne City Link Project links major freeways and access roads. The permanent excavation covers an area of 3 ha and extends to a maximum depth of 9 m, which is 6 m below the ground water table. Design and construction approaches were developed to (i) control seepage into the excavation to limit groundwater lowering beyond the site, and (ii) limit the effects of potentially damaging base heave during construction. Lateral flow of groundwater into the excavation was controlled by a cut-off wall extending through the compressible clay with a surrounding line of closely spaced recharge wells. Analyses showed the recharge wells in combination with the wall would be effective in limiting drawdown outside the site. Monitoring showed that pore water pressures were maintained within the design criteria, with the assistance of deep recharge of an underlying aquifer to control vertical seepage. Survey showed settlements outside the site were minimal. Shallow pressure relief drains were installed to limit uplift pressures and control base instability in the deepest parts of the excavation. Monitoring of the groundwater levels in the underlying aquifer and comparisons with results from flow models were used to successfully control uplift pressures during construction.Key words: clay, settlement, groundwater, excavation, recharge, construction.
ATTEMPT AT IN-AIR PIXE ANALYSIS OF SPOT SAMPLES ON A FILTER-TAPE MOUNTED IN AN AUTOMATED BETA-RAY ABSORPTION MASS MONITOR
Authors: SAITOH KATSUMI , IMASEKI HITOSHI , YUKAWA MASAE
Published: October 2004

We attempted in-air-PIXE analysis of SPM using spot samples on a filter-tape mounted in an automated beta-ray absorption mass monitor. Al , Si , S , Fe and Zn , etc., which are of interest for identifying the behavior and characteristics of SPM, were detected on the SPM spot samples on a glass-fiber filter-tape, but the peaks of these elements were nearly identical to those of blank glass-fiber filter-tape. As such, it was difficult to detect elements present in SPM from the X-ray spectra of the spot samples. On the other hand, in the case of a PTFE membrane filter-tape, the S peak was distinct and the Fe peak was also clear, and peaks for elements Al , Mn and Zn , etc., were also confirmed. Consequently, if a method for determining quantity is established, direct multi-elemental analysis by in-air-PIXE of high time-resolution SPM spot samples collected on a PTFE membrane filter-tape mounted in a SPM monitor will be possible.
SULFUR IN A FOSSIL WOOD FROM THE PLEISTOCENE MARINE CLAY
Authors: KAGEMORI K. , AIKAWA N. , ISHIMARU K. , KAWAI S. , YUKAWA M. , IMASEKI H. , SERA K. , FUTATSUGAWA S.
Published: October 2004

In anoxic marine sediments sulfur is considered to be essential to the formation of humic substances. It is also estimated that sulfur may play a crucial role in the degradation of wood buried in marine sediments. In order to confirm this prediction, we observed the tissue of fossil wood from the marine clay aged 1.1 million years by polarizing microscopy and SEM before the determination of its sulfur content by PIXE and EDXA, and its distribution by μ-PIXE. Results show that the sample contained about 6000 μg/g of total sulfur and tracheid cells with birefringence, which have probably preserved the original wood components contain less sulfur compared to those without birefringence, which are heavily degraded. This might suggest the participation of sulfur in the degradation or the formation of humic substances occurred in wood tissue during diagenesis.
SOLUTIONS WITHOUT SINGULARITIES IN GAUGE THEORY OF GRAVITATION
Authors: ZET G. , OPRISAN C. D. , BABETI S.
Published: October 2004

A de-Sitter gauge theory of the gravitational field is developed using a spherical symmetric Minkowski space–time as base manifold. The gravitational field is described by gauge potentials and the mathematical structure of the underlying space–time is not affected by physical events. The field equations are written and their solutions without singularities are obtained by imposing some constraints on the invariants of the model. An example of such a solution is given and its dependence on the cosmological constant is studied. A comparison with results obtained in General Relativity theory is also presented.
Aqueous Extract of Ma huang Suppresses Neuropeptide Y Expression in Food-Deprived Rat Hypothalamus
Authors: Kim Ee-Hwa , Shin Mal-Soon , Chang Hyun-Kyung , Lee Taeck-Hyun , Jang Mi-Hyeon , Shin Min-Chul , Lee Sam-Jun , Kim Chang Ju
Published: October 2004

Ma huang, the dried plant stem of Ephedra Intermedia Schrenk et C.A., contains an ephedrine-type alkaloid and has been used for weight loss. Neuropeptide Y (NPY), a 36-amino acid peptide, is concentrated in the hypothalamus and stimulates feeding desire. In this study, the effect of Ma huang on the expressions of NPY in the hypothalamus of rats was investigated using immunohistochemistry. Food-deprivation enhanced the NPY expression in the hypothalamus. Ma huang suppressed the food-deprivation-induced enhancement of NPY expression. Present results suggest that Ma huang curbs the food desire by suppressing the NPY expression under food-deprivation conditions.
Electroacupuncture Reduces Stress-Induced Expression of c-Fos in the Brain of the Rat
Authors: Lee Hye-Jung , Lee Bombi , Choi Sun-Hye , Hahm Dae-Hyun , Kim Mi-Rye , Roh Pyung-Ui , Pyun Kwang-Ho , Golden Gregory , Yang Chae-Ha , Shim Insop
Published: October 2004

We have previously shown that electroacupuncture (EA) at Shaohai and Neiguan ( HT 3- PC 6) points significantly attenuated stress-induced peripheral responses, including increases in blood pressure, heart rate and plasma catecholamines. In this study, we examined the central effect of EA on the expression of c-fos, one of the immediate-early genes in the brain of rats subjected to immobilization stress. Immobilization stress (180 minutes) preferentially produced a significant increase in Fos-like immunoreactivity (FLI) in stress-relevant regions including the paraventricular hypothalamic nucleus (PVN), arcuate nucleus (ARN), supraoptic nucleus (SON), suprachiasmatic nucleus (SCN), medial amygdaloid nucleus (AMe), bed nucleus of the stria terminalis (BST), hippocampus, lateral septum (LS), nucleus accumbens, and the locus coeruleus (LC). EA (3 Hz, 0.2 ms rectangular pulses, 20 mA) at HT 3- PC 6 on the heart and pericardium channels for 30 minutes during stress, significantly attenuated stress-induced FLI in the parvocellular PVN, SON, SCN, AMe, LS and the LC. However, EA stimulations at HT 3- PC 6 had no effect on FLI in the magnocelluar PVN, ARN, BST or the hippocampus. EA stimulation at HT 3- PC 6 had a greater inhibitory effect on stress-induced FLI than that at TE 5- LI 11, the triple energizer and large intestine meridian, or non-acupoints. These results demonstrated that EA attenuated stress-induced c-fos expression in brain areas. These results suggest that decreased c-fos expression in hypothalamic and LC neurons, among stress-related areas, may reflect the integrative action of acupuncture in stress response.
PREDICTIONS AND RECENT RESULTS IN SUSY ON THE LATTICE
Authors: FEO ALESSANDRA
Published: October 2004

In this brief review, we summarize the current theoretical knowledge in supersymmetry on the lattice, with special emphasis on recent results in the framework of N=1 supersymmetric Yang–Mills theory, Wess–Zumino model and Yang–Mills theory with extended supersymmetries.
SCALAR COSMOLOGICAL PERTURBATION IN AN INFLATIONARY BRANE WORLD DRIVEN BY THE BULK INFLATON
Authors: DU DA-PING , WANG BIN , ABDALLA ELCIO , SU RU-KENG
Published: October 2004

We investigate scalar perturbations from inflation in a bulk inflaton brane world model. Using the generalized longitudinal gauge, we derive and solve the full set of scalar perturbation equations. Our exact results support the recent argument that for the de Sitter brane the square of the radion mass is not positive, showing that unlike the flat brane case, the de Sitter brane is not stable.
PSEUDO-RANDOM NUMBER GENERATOR BASED ON COUPLED MAP LATTICES
Authors: LÜ HUAPING , WANG SHIHONG , HU GANG
Published: October 2004

A one-way coupled chaotic map lattice is used for generating pseudo-random numbers. It is shown that with suitable cooperative applications of both chaotic and conventional approaches, the output of the spatiotemporally chaotic system can easily meet the practical requirements of random numbers, i.e., excellent random statistical properties, long periodicity of computer realizations, and fast speed of random number generations. This pseudo-random number generator system can be used as ideal synchronous and self-synchronizing stream cipher systems for secure communications.
SELF-CONSISTENT-FIELD THEORY FOR SPHERICAL POLYMERIC ASSEMBLIES AND ITS APPLICATION
Authors: ROAN JIUNN-REN
Published: October 2004

Combining Edwards' self-consistent-field (SCF) theory and numerical techniques borrowed from fluid dynamics, I have developed a SCF theory for spherical polymeric assemblies. The theory is being used to determine the equilibrium structure of a polymer layer formed by immiscible polymers end-grafted onto a spherical nanoparticle. Here I report some of the preliminary results.
COLLECTIVE DIRECTIONAL TRANSPORT AND COUPLED BROWNIAN RATCHETS
Authors: ZHENG ZHIGANG
Published: October 2004

Recent progresses on collective directional transport in coupled systems are overviewed. By considering the mutual interactions among elements, the directed ratchet motion exhibits complicated and novel cooperative dynamics. The directional transport can be induced not only by breaking the spatial symmetry of the substrate potential, but also by breaking the coupling symmetry and the spatiotemporal symmetries.
STATISTICS AND DEVELOPING MODEL OF CHINESE SKYWAY NETWORK
Authors: HE YUE , ZHU XIANGYANG , HE DA-REN
Published: October 2004

Chinese skyway network is investigated. Nodes are defined as the Airports. Edges are defined as skyways. The statistical properties of the network in 2002, 1998 and 1978 are obtained. A simple dynamical model, which may reproduce the developing process of the network, is suggested. The simulation results show a good agreement with the statistical results.
COOPERATION IN THE EVOLUTIONARY MULTIPLE-CHOICE MINORITY GAME
Authors: QUAN H. J. , WANG BING-HONG , YANG W. S. , HUI P. M. , LUO X. S.
Published: October 2004

An evolutionary multiple-choice minority game is investigated. In the model, each agent chooses one option out of Nc options. Each agent is assigned a single parameter p (0≤p≤1) that he chooses his best performing strategy of his s strategies for decision. With probability 1-p he chooses his worst performing strategy. If the agent's wealth falls below a value d(d<0), his p value is allowed to modify by picking a new value with a range of R of the old p value. Numerical results reveal that the evolution can considerably enhance the system's coordination.
CELLULAR AUTOMATON MODEL SIMULATING TRAFFIC FLOW AT AN UNCONTROLLED T-SHAPED INTERSECTION
Authors: LI XIAO-BAI , JIANG RUI , WU QING-SONG
Published: October 2004

Traffic flow at an uncontrolled T-shaped intersection is modelled by a cellular automaton model. A priority probability of the through car is introduced. The phase diagram of the system and the effect of the turning car on the whole traffic situation are investigated. Our simulation results suggest that priority should be given to either through cars or to turning cars according to the ratio of the turning cars in order to obtain the optimization of the system.
SOLITONS IN A MONOATOMIC CHAIN WITH KAC–BAKER-LIKE LONG-RANGE INTERACTION POTENTIAL
Authors: WANG D. L. , YAN X. H. , TANG Y. , XIAO Y. F. , YANG R. S.
Published: October 2004

By using the method of multiple-scale and the continuum approximation, we study the nonlinear properties of a monoatomic chain with Kac–Baker-like long-range harmonic interaction. It is shown that the dispersion relation, the group velocity and the amplitude of solitons exhibit some new characters different from that of the nonlinear chain without Kac–Baker-like long-range harmonic interaction.
POWER-LAW DISTRIBUTIONS IN CIRCULATING MONEY: EFFECT OF PREFERENTIAL BEHAVIOR
Authors: DING NING , WANG YOUGUI , XU JUN , XI NING
Published: October 2004

We introduce preferential behavior into the study on statistical mechanics of money circulation. The computer simulation results show that the preferential behavior can lead to power laws on distributions over both holding time and amount of money held by agents. However, some constraints are needed in generation mechanism to ensure the robustness of power-law distributions.
QUANTUM CHAOS IN NON-SYMMETRIC POTENTIAL WELL IN A TILTED MAGNETIC FIELD
Authors: YUAN GUOYONG , YANG SHIPING , FAN HONGLING , CHANG HONG
Published: October 2004

In this paper, the dynamical behavior of a non-symmetric double potential well in a tilted magnetic field is studied. The classical Poincare section is given to exhibit the chaotic behavior of the system, and non-linear resonant lead to chaos. The paper has also given the energy spectral statistics which satisfies Brody's distribution, tunnelling effect develops quantum chaos and also holds back the development of chaos.
SPECIFIC FORCES BETWEEN DNA BASES
Authors: PINCET FRÉDÉRIC , PEREZ ERIC , BRYANT GARY , LEBEAU LUC , MIOSKOWSKI CHARLES
Published: October 2004

Molecular recognition occurs at all levels of living matter but the mechanisms are not understood in physical terms. One striking example is that of DNA whose properties are intimately related to the specific molecular interactions of four nucleosides, based on hydrogen-bonds and size complementarities. We have directly measured the interaction between two of them, adenosine and thymidine, using a surface force apparatus. In these experiments, lipids functionalised with nucleosides were synthesised, and used to coat the surfaces between which forces were measured. The interactions of complementary molecules were compared to those, markedly different, for which the complementarity was hindered by a small modification of one of the molecules. The distance range of the specific forces, deduced from this comparison, was surprisingly long. The adhesion energy of the surfaces covered by these nucleosides were highly specific. Binding energies obtained from these measurements were in good agreement with values from the literature. The results also show that without the size effect existing in DNA, H-bonds alone can generate the specificity. An unusual behaviour, attributed to the sticky and fluid character of the layers, was pointed out. A long-range non specific interaction, also unexpected, was found. These features observed on surfaces coated with chemical functional groups may partly result from a collective behaviour. They illustrate the variety of physical effects one can obtain by playing on the chemistry of a surface.
COULOMB DRAG IN DOUBLE QUANTUM WELLS WITH A PERPENDICULAR MAGNETIC FIELD
Authors: WU M.W. , CUI H.L. , HORING N.J.M.
Published: October 2004

Momentum transfer due to electron–electron interaction (Coulomb drag) between two quantum wells, separated by a distance d, in the presence of a perpendicular magnetic field, is studied at low temperatures. We find besides the well known Shubnikov-de Haas oscillations, which also appear in the drag effect, the momentum transfer is markedly enhanced by the magnetic field.
ELECTRON–HOLE BRANCH IMBALANCE IN SUPERCONDUCTORS INITIATED BY ABSORPTION OF HIGH-ENERGY QUANTA
Authors: GULIAN A.M. , VECHTEN D. VAN
Published: October 2004

The creation of quasiparticle branch imbalance in superconductors, when pumped by high-energy quanta, is considered. The physical basis for imbalance creation lies in the geometrical difference between the electron- and hole-like excitation densities of states in momentum space. Simple analytical solutions for distribution functions of electron- and hole-like excitations are derived using appropriately modified kinetic equations. The relevance of results to the problem of high-energy particle detection is discussed.
CAVITY QUANTUM ELECTRODYNAMICS OF COMPETING ONE AND TWO PHOTON PROCESSES
Authors: JOSHI AMITABH
Published: October 2004

We consider a new model of cavity quantum electrodynamics consisting of the interaction of a single mode of electromagnetic field with two non-identical two-level atoms undergoing one and two photon transition respectively in an ideal cavity. The exact analytic results for the vacuum Rabi splitting and the dynamical evolution of the model are given.
EFFECTS OF V- OR Cr-DOPING ON PHASE FORMATION, ELECTRIC PROPERTIES AND SUPERCONDUCTIVITY OF THE 3212-TYPE PHASE Pb2Sr2(Ca0.5Y0.5)Cu3Oz
Authors: CHEN Z.Y. , Qian Y.T. , LUO H.M. , QU B. , SHENG Z.Z. , WANG L.M.
Published: October 2004

The effects of vanadium or chromium on the formation, electric properties and superconductivity of Pb-3212 phase ( Pb 2 Cu ) Sr 2( Ca 0.5 Y 0.5) Cu 2 O z are studied. The sites of V or Cr in PbO–CuO δ– PbO structure unit for Pb -3212 phase is also investigated. Compared with the effects of Cr-doping, V can totally substitute Ca to form a new compound Pb 2 Sr 2( V 0.5 Y 0.5) Cu 3 O z, and V has relatively greater substitution amount in ( Pb 2–x M x) Sr 2( Ca 0.5 Y 0.5) Cu 3 O z( M = Cr or V ). Moreover, the resistivity and superconductivity of the above samples decrease with increasing V or Cr amount. Among them, the effects of V is greater, and its location (in Pb or Ca site) also affects greatly the superconductivity.
A STUDY ON Yb1−xDyxBa2Cu3O7−y SUPERCONDUCTOR
Authors: SRINIVAS S. , BHATNAGAR A.K. , PALKAR V.R. , MULTANI M.S.
Published: October 2004

Bulk samples of Yb 1−x Dy x Ba 2 Cu 3 O 7−y composition, where (x=0, 0.25, 0.5, 0.75 and 1.0) are prepared and studied with respect to formation of superconducting 123 orthorhombic phase. It is found that the orthorhombicity as well as superconducting transition temperature (T co ) increase almost linearly with the Dy concentration. Samples with x=0 and x=1 have T co =87.6 K and 90.2 K, respectively.
SPIN AND CHARGE FLUCTUATION IN CUPRATE OXIDE SUPERCONDUCTORS
Authors: ZHANG MING-LIANG , ZHAO ZHONG-XIAN
Published: October 2004

Spin and charge fluctuation are obtained from a two-band model making use of saddle point approximation in path-integral form.
STRUCTURAL AND MAGNETIC BEHAVIOR OF HIGH TcY1−xGaxBa2Cu3O7−δ SUPERCONDUCTORS
Authors: POP IULIU , REDAC RADU , BURDA IOAN , IONCU VIRGIL
Published: October 2004

Four samples of high T c superconductors Y 1−x Ga x Ba 2 Cu 3 O 7−δ, with x=0.2; 0.3 and x=1 were synthesized. The resulted samples were analysed from a structural and magnetic view point. The X ray spectrum relieved the existence of the orthorhomhic structure and some of unreacted BaCO 3 and CuO lines.

The temperature dependence of the magnetic susceptibility pointed out the diamagnetic transmission with the critical temperature at 79 K for x=0.2 and 0.3. For the samples x=1 sintered at 1,223 and at 1,273 K the critical temperatures were 77, 5 and 78 K.
TIGHT-BINDING MOLECULAR DYNAMICS STUDY OF C60, C116 AND C120
Authors: CAO ZHILIANG , YU XUEPING , XIANG JIBING , DING PEIZHU , HAN RUSHAN
Published: October 2004

The geometric structures of C 60, C 116 and C 120 in their ground states are obtained by tight-binding dynamic molecular simulation (TBMD). We find that the ground state of C 60 has high symmetry, Ih, but C 116 and C 120 have low symmetry, D2h. The energy bands and vibrational modes of C 116 and C 120 are complex compared with C 60. Some of them can be easily recognized as C 60 derived and are no longer degenerate but very close, and others are produced by the interaction and relative movement between two C 58 or two C 60.
N2 LASER INDUCED PHOTOLUMINESCENCE EMISSION IN (ZnS: ZnO):Cu PHOSPHORS
Authors: MURALEEDHARAN R. , KHOKHAR M.S.K. , NAMBOODIRI V.P. , GIRIJAVALLABHAN C.P.
Published: October 2004

Nitrogen laser induced photoluminescence (PL) emissions from (ZnS: ZnO):Cu powder phosphors have been carried out under varying conditions of sample preparation. The conditions for optimum efficiency of PL emission in (ZnS: ZnO):Cu phosphors and their spectral characteristics have been investigated. The emission peak in the PL spectra was found to shift towards longer wavelengths side as the concentrations of ZnO in (ZnS: ZnO) mixture was varied from 0% to 100%. The mechanism of PL emission in the above phosphor is explained on the basis of classical “Schon-Klassen” model.
SPONTANEOUS EMISSION BY MOVING ATOMS UNDERGOING TWO PHOTON-TRANSITION IN THE STRONG COUPLING REGIME
Authors: JOSHI AMITABH
Published: October 2004

The dependence of spontaneous emission on atomic motion for an atom undergoing two-photon transition and moving along the axis of a Fabry-Perot cavity is analyzed here. For this purpose we consider the strong coupling limit of atom and cavity field mode and demonstrate the effects of atomic velocity and spatial mode structure of cavity mode on the excitation probability of atom.
EFFECT OF STRONG MAGNETIC FIELDS ON THE EQUILIBRIUM OF A DEGENERATE GAS OF NUCLEONS AND ELECTRONS
Authors: HO CHOON-LIN , KHALILOV V.R. , YANG CHI
Published: October 2004

We obtain the equations that define the equilibrium of a homogeneous relativistic gas of neutrons, protons and electrons in a constant magnetic field as applied to the conditions that probably occur near the center of neutron stars. We compute the relative densities of the particles at equilibrium and the Fermi momentum of electrons in the strong magnetic field as function of the density of neutrons and the magnetic field induction. Novel features are revealed as to the ratio of the number of protons to the number of neutrons at equilibrium in the presence of large magnetic fields.
DIELECTRIC AND PIEZOELECTRIC PROPERTIES OF POLYMER PIEZOELECTRIC 3–0 COMPOSITES
Authors: PRASAD G. , BHIMASANKARAM T. , SURYANARAYANA S.V. , KUMAR G.S.
Published: October 2004

The mixture rules of dielectric constants of biphasic polymer-piezoelectric composites with 3–0 connectivity have been modified by taking into account the local field interactions. The solution of Laplace equation for the scalar potential inside and outside the piezoelectric sphere dispersed in polymer matrix is obtained by using the proper boundary conditions. Using the local electric field obtained from the potential, an expression for the dielectric constant of the composite is obtained. An approach is developed by which, using modified mixture rules, the piezoelectric constants of composites can be estimated. The developed expressions are functions of dielectric, elastic, piezoelectric constants and volume fractions of constituent phases and compare very favourably with the available experimental data.
ELECTRIC, MAGNETIC AND STRUCTURAL PROPERTIES OF HIGH-Tc OXYDIC SUPERCONDUCTORS Y2Ba4CanCun+6O2n+14
Authors: HOMORODEAN L. , POP I. , BURDA I. , ANDRECUT M. , BORODI G.
Published: October 2004

A new series of oxydic superconductors, Y 2 Ba 4 Ca n Cu n+6 O 2n+14, was synthesized. By X-ray diffraction method was pointed out that the samples are 123 phase superconductors. The temperature dependence of the electrical resistivity pointed out the zero-baseline, a linear increase and a jump. The thermal variation of the magnetic susceptibility exhibits the diamagnetic transition i.e. Tc(χ=0).
HIGH DIELECTRIC CONSTANT AND NONLINEAR ELECTRIC RESPONSE IN Bi2Sr2SmCu2Oy
Authors: SEKHAR M. CHANDRA , KRISHNA B. GOPALA , KUMAR M. MAHESH , SURYANARAYANA S.V.
Published: October 2004

Samples with the nominal composition Bi 2 Sr 2 SmCu 2 O y were prepared by solid state reaction method. From the room temperature X-ray diffraction data, it was found that the sample is similar to the Bi-2212 structure. DC electrical resistivity was done from 80 K to 573 K and the impedance measurements were performed from 80 K to 573 K at different frequencies in the range of 10 kHz to 800 kHz. The sample Bi 2 Sr 2 SmCu 2O y has exhibited semiconducting behavior in the low temperature region (80 K to 343 K), metallic behavior in the temperature range of 343 K to 443 K and again semiconducting behavior above 443 K. The sample has exhibited the phenomenon of variable rangehopping mechanism (VRH). The physical parameters related to VRH such as localization length (a), hopping distance (R) and hopping energy (W) have been evaluated and discussed. The activation energy in the high temperature region (above 300 K) decreases with increasing frequency. Tan δ increases with increase in temperature (303 K-573 K), which is attributed to increased conductivity. The dielectric constant increases with increase in temperature. For a given temperature the value of ε is found to decrease with increase in frequency.
SPECTRAL CORRELATIONS IN DISORDERED MESOSCOPIC METALS AND THEIR RELEVANCE FOR PERSISTENT CURRENTS
Authors: VÖLKER AXEL , KOPIETZ PETER
Published: October 2004

We use the Lanczos method to calculate the variance σ2(E, ϕ) of the number of energy levels in an energy window of width E below the Fermi energy for noninteracting disordered electrons on a thin three-dimensional ring threaded by an Aharonov–Bohm flux ϕ. We confirm numerically that for small E the flux-dependent part of σ2(E, ϕ) is well described by the Altshuler–Shklovskii-diagram involving two Cooperons. However, in the absence of electron–electron interactions this result cannot be extrapolated to energies E where the energy-dependence of the average density of states becomes significant. We discuss consequences for persistent currents and argue that for the calculation of the difference between the canonical- and grand canonical current it is crucial to take the electron–electron interaction into account.
QUASIHYDROSTATIC PRESSURE DEPENDENCE OF TcinHgBa2Ca3Cu4O10+δandHgBa2Ca4Cu5O12+δ
Authors: QIU X.D. , GAO L. , LIN Q.M. , XUE Y.Y. , CHU C.W.
Published: October 2004

The superconducting transition temperature T c has been studied under quasihydrostatic pressure (QHP) up to 16 GPa for the HgBa 2 Ca n-1 Cu n O 2n+δ [ Hg -12{n−1}n] samples with n=4 and 5. The applied pressure shifts T c toward higher temperature in both cases. But the T c -enhancement under pressure for these two compounds is significantly smaller than the previously reported universal T c -enhancement in Hg-1201, Hg-1212 and Hg-1223.
THE INFLUENCE OF SPIN-REORIENTATION ON THE DIELECTRIC BEHAVIOUR OF COBALT SUBSTITUTED W-TYPE BARIUM–ZINC HEXAGONAL FERRITES
Authors: REDDY V. DEVENDER , PURUSHOTHAM Y. , REDDY M. BHAGAVANTHA , REDDY P. VENUGOPAL
Published: October 2004

Dielectric measurements of cobalt substituted W-type barium–zinc hexagonal ferrites are undertaken both as a function of frequency and temperature. The dielectric constant is found to decrease continuously with increasing frequency while it increases continuously with increasing temperature. The variation of dielectric constant with dopants concentration is explained on the basis of magnetic cation orientation. From the temperature variation of dielectric constant two transitions, one due to the spin reorientation in the temperature range 450–500 K and the other one due to a ferri to paramagnetic transition have been observed. Suitable explanations for the observed behavior are given.
SYNTHESIS OF ULTRAFINE/NANOSIZE POWDERS OF IRON OXIDES BY PULSED LASER ABLATION AND COLD CONDENSATION
Authors: SHINDE S. R. , BANPURKAR A. G. , ADHI K. P. , LIMAYE A. V. , OGALE S. B. , DATE S. K. , MAREST G.
Published: October 2004

Ultrafine/nanosize powders of iron oxide have been synthesized from a sintered α- Fe 2 O 3 target by pulsed excimer laser ablation and cold condensation. The influence of target porosity and temperature of condensation on the formation of nanosize particles has been studied. The nanosize powders have been characterized by X-ray diffraction, Mössbauer spectroscopy, vibrating sample magnetometry and scanning electron microscopy. It is shown that the formation of ultrafine/nanosize particles is strongly governed by the target porosity, whereas, the temperature of condensation, over a range from 27°C to −130°C, does not affect the magnetic properties of the nanoparticles.
LINKS BETWEEN THE QUANTUM HALL EFFECT, CHIRAL BOSON THEORIES AND STRING THEORY
Authors: BRACKEN PAUL
Published: October 2004

Chiral boson theory is introduced and its relevance to the quantum Hall effect is explained. It is shown that the chiral boson theory admits mode expansions which are essentially those which appear and are made use of in bosonic string theories. This immediately leads to a way of quantizing the theory. Restrictions on various parameters appearing in the model can be imposed in a natural way. Finally, it is suggested that some of these ideas have important applications to other geometries which could give rise to new types of physical behavior.
RELATION BETWEEN STRONG AND WEAK ISOSPIN
Authors: ROBSON B. A.
Published: October 2004

The relation between strong isospin I and weak isospin i is discussed. In particular an equation between the third components I3 and i3 is given. This relation indicates that the strong isospin and weak isospin symmetries are both SU (2) subgroups of a new SU (3) symmetry underlying the structure of leptons and quarks.
FUZZY MATRICES WITH COMPLETE TRANSITIVITY
Authors: LIU WEN-BIN , SUN HUA-CHUN , DONG JUNYU
Published: October 2004

We extend previous work regarding the transitivity of fuzzy matrices and propose the concept of completely transitive matrices. We further investigate their properties, indices, periods and relations with canonical fuzzy matrices. Our research shows that the completely transitive matrix type is a novel type, which contains previously defined transitive matrix types. Based on the proposed theories, we illustrate that completely transitive matrices can be applied in fuzzy orderings.
REPLICATION AND EVOLUTION OF QUANTUM SPECIES
Authors: PATI ARUN K.
Published: October 2004

We dwell upon the physicist's conception of 'life' since Schrödinger and Wigner through to the modern-day language of living systems in the light of quantum information. We discuss some basic features of a living system such as ordinary replication and evolution in terms of quantum bio-information. We also discuss the principle of no-culling of living replicas. We show that in a collection of identical species there can be no entanglement between one of the mutated copies and the rest of the species in a closed universe. Even though these discussions revolve around 'artificial life' they may still be applicable in real biological systems under suitable conditions.
SPIRAL WAVE MAINTAINED BY NOISE
Authors: LEI AI ZHONG , LI QIAN SHU , XU WEIGUO , HU DAIPING
Published: October 2004

The effect of Gaussian white noise on a chemical wavefront is studied in a modified FitzHugn–Nagumo model by applying numerical simulations. A rotating spiral waves can be formed if the medium is excitable enough and the fronts has a free end, when the reaction diffusion system is disturbed by a certain non-zero level noise. It is counterintuitive that noise plays a constructive role in the product and propagation of single spiral waves in this letter. Weak or strong noise will make against the product and propagation of spiral waves. In a certain noise level, spiral wave can be maintained in a medium, where such spiral waves cannot be observed in the absence of the noise.
INTER-PATTERN TRANSITIONS IN A NOISY BURSTING CELL
Authors: SOSNOVTSEVA O. V. , POSTNOVA S. D. , MOSEKILDE E. , BRAUN H. A.
Published: October 2004

This paper studies the deterministic and stochastic dynamics of a thermo-receptor model. Special emphasis is paid to the transition zones between the main spiking patterns. In these zones, noise can induce or suppress spike generation, allowing for a nonmonotoneous dependence of the mean firing rate on the noise intensity. We show how this peculiar dependence can be explained in terms of bifurcation phenomena in the underlying deterministic model.
Stearoyl-CoA desaturase 1 deficiency increases insulin signaling and glycogen accumulation in brown adipose tissue
Authors: Rahman Shaikh Mizanoor , Dobrzyn Agnieszka , Lee Seong-Ho , Dobrzyn Pawel , Miyazaki Makoto , Ntambi James M.
Published: October 2004

Stearoyl-CoA desaturase (SCD) catalyzes the synthesis of oleate (C18:1) and palmitoleate (C16:1), which are the main monounsaturated fatty acids of membrane phospholipids, triglycerides, wax esters, and cholesterol esters. Previously, we showed that SCD1 deficiency elevates insulin-signaling components and downregulates protein-tyrosine phosphatase-1B (PTP-1B) in muscle, a major insulin-sensitive tissue. Here we found that, in brown adipose tissue (BAT), another insulin-sensitive tissue, the basal tyrosine phosphorylations of insulin receptor (IR) and IR substrates (IRS-1 and IRS-2) were upregulated in SCD1−/−mice compared with wild-type mice. The association of IRS-1 and IRS-2 with the α-p85 subunit of phosphatidylinositol 3-kinase as well as Akt-Ser473and Akt-Thr308phosphorylation is also elevated in the SCD1−/−mice. The mRNA expression, protein levels, and activity of PTP-1B implicated in the attenuation of the insulin signal are reduced in the SCD1−/−mice. The content of GLUT4 in the plasma membrane increased 2.5-fold, and this was accompanied by a 6-fold increase in glucose uptake in BAT of SCD1−/−mice. The increased glucose uptake was associated with higher glycogen synthase activity and glycogen accumulation. In the presence of insulin, [U-14C]glucose incorporation into glycogen was increased in BAT of SCD1−/−mice. Taken together, these studies illustrate increased insulin signaling and increased glycogen metabolism in BAT of SCD1−/−mice.
Effects of diabetes and recurrent hypoglycemia on the regulation of the sympathoadrenal system and hypothalamo-pituitary-adrenal axis
Authors: Inouye Karen E. , Chan Owen , Yue Jessica T. Y. , Matthews Stephen G. , Vranic Mladen
Published: October 2004

Epinephrine, norepinephrine, and corticosterone responses to hypoglycemia are impaired in diabetic rats. Recurrent hypoglycemia further diminishes epinephrine responses. This study examined the sympathoadrenal system and hypothalamo-pituitary-adrenal axis for molecular adaptations underlying these defects. Groups were normal (N) and diabetic (D) rats and diabetic rats exposed to 4 days of 2 episodes/day of hyperinsulinemic hypoglycemia (D-hypo) or hyperinsulinemic hyperglycemia (D-hyper). D-hypo and D-hyper rats differentiated effects of hypoglycemia and hyperinsulinemia. Adrenal tyrosine hydroxylase (TH) mRNA was reduced ( P < 0.05 vs. N) 25% in all diabetic groups. Remarkably, mRNA for phenylethanolamine N-methyltransferase (PNMT), which converts norepinephrine to epinephrine, was reduced ( P < 0.05 vs. all) 40% only in D-hypo rats. Paradoxically, dopamine β-hydroxylase mRNA was elevated ( P < 0.05 vs. D, D-hyper) in D-hypo rats. Hippocampal mineralocorticoid receptor (MR) mRNA was increased ( P < 0.05 vs. N) in all diabetic groups. Hippocampal glucocorticoid receptor (GR), hypothalamic paraventricular nucleus (PVN) GR and corticotropin-releasing hormone (CRH), and pituitary GR and proopiomelanocortin (POMC) mRNA levels did not differ. We conclude that blunted corticosterone responses to hypoglycemia in diabetic rats are not due to altered basal expression of GR, CRH, and POMC in the hippocampus, PVN, and pituitary. The corticosterone defect also does not appear to be due to increased hippocampal MR, since we have reported normalized corticosterone responses in D-hypo and D-hyper rats. Furthermore, impaired epinephrine counterregulation in diabetes is associated with reduced adrenal TH mRNA, whereas the additional epinephrine defect after recurrent hypoglycemia is associated with decreases in both TH and PNMT mRNA.
Insulin potentiates AVP-induced AQP2 expression in cultured renal collecting duct principal cells
Authors: Bustamante Mauro , Hasler Udo , Kotova Olga , Chibalin Alexander V. , Mordasini David , Rousselot Martine , Vandewalle Alain , Martin Pierre-Yves , Féraille Eric
Published: October 2004

In the renal collecting duct (CD), water reabsorption depends on the presence of aquaporin-2 (AQP2) in the apical membrane of principal cells. AQP2 expression and subcellular repartition are under the control of AVP. Some pieces of experimental evidence indicate that additional hormonal factors, including insulin, may also control AQP2 expression and thereby CD water permeability. We have previously shown that AVP induces endogenous AQP2 expression in cultured mouse mpkCCDcl4CD principal cells ( 23 ). In the present study, we investigated the effect of insulin on AQP2 expression in mpkCCDcl4cells. Addition of insulin to the basal medium of cells grown on filters slightly increased AQP2 mRNA and protein expression, whereas insulin potentiated the effect of AVP. The potentiation of AVP-induced AQP2 expression by insulin was abolished by actinomycin D, a transcriptional inhibitor. Analysis of AQP2 protein expression under conditions of AVP washout and/or in the presence of chloroquine, a lysosomal degradation inhibitor, revealed that insulin did not significantly alter AQP2 protein degradation. Inhibition of ERK, p38 kinase, and phosphatidylinositol 3′-kinase (PI 3-kinase) activities prevented the insulin-induced stimulation of AQP2 expression, whereas inhibition of PKC has no effect. Taken together, our results indicate that insulin increased AQP2 protein expression mostly through increased AQP2 mRNA levels in cultured mpkCCDcl4cells. This effect most likely relies on increased AQP2 gene transcription in response to MAPK and PI 3-kinase activation.
Auditory-Feedback Control of Temporal Call Patterns in Echolocating Horseshoe Bats
Authors: Smotherman Michael , Metzner Walter
Published: October 2004

During flight, auditory feedback causes horseshoe bats to adjust the duration and repetition rate of their vocalizations in a context-dependent manner. As these bats approach a target, they make finely graded adjustments in call duration and interpulse interval (IPI), but their echolocation behavior is also characterized by abrupt transitions in overall temporal calling patterns. We investigated the relative contributions of two prominent acoustic cues, echo frequency and delay, toward the control of both graded and transitional changes in call duration and IPI. Echoes returning at frequencies above the emitted call frequency caused bats to switch from long single calls to pairs of short calls (doublets). Alternatively, increasing echo delay caused progressive increases in IPI but caused no accompanying changes in call duration. When frequency shifts were combined with changing echo delays, echo delay altered the IPIs occurring between doublets but not the IPI within a doublet. When the echo mimic was replaced by presentation of either an artificial constant-frequency (CF) stimulus or a frequency-modulated (FM) stimulus, each designed to mimic major components of the echo acoustic structure, we found that CF stimuli could trigger the switch to doublets, but changing CF delay had no influence on IPI, whereas the timing of an FM-sweep presentation had a strong effect on IPI. Because CF and FM sounds are known to be processed separately in the bat auditory system, the results indicate that at least two distinct neural feedback pathways may be used to control the temporal patterns of vocalization in echolocating horseshoe bats.
Temporal Evolution of Oscillations and Synchrony in GPi/Muscle Pairs in Parkinson's Disease
Authors: Hurtado José M. , Rubchinsky Leonid L. , Sigvardt Karen A. , Wheelock Vicki L. , Pappas Conrad T. E.
Published: October 2004

Both standard spectral analysis and time-dependent phase correlation techniques were applied to 27 pairs of tremor-related single units in the globus pallidus internus (GPi) and EMG of patients with Parkinson's disease (PD) undergoing stereotactic neurosurgery. Over long time-scales (∼60 s), GPi tremor-related units were statistically coherent with restricted regions of the peripheral musculature displaying tremor. The distribution of pooled coherence across all pairs supports a classification of GPi cell/EMG oscillatory pairs into coherent or noncoherent. Analysis using ∼2-s sliding windows shows that oscillatory activity in both GPi tremor units and muscles occurs intermittently over time. For brain/muscle pairs that are coherent, there is partial overlap in the times of oscillatory activity but, in most cases, no significant correlation between the times of oscillatory subepisodes in the two signals. Phase locking between coherent pairs occurs transiently; however, the phase delay is similar for different phase-locking subepisodes. Noncoherent pairs also show episodes of transient phase locking, but they occurred less frequently, and no preferred phase delay was seen across subepisodes. Tremor oscillations in pallidum and EMGs are punctuated by phase slips, which were classified as synchronizing or desynchronizing depending on their effect on phase locking. In coherent pairs, the incidence of synchronizing slips is higher than desynchronizing slips, whereas no significant difference was seen for noncoherent pairs. The results of this quantitative characterization of parkinsonian tremor provide a foundation for hypotheses about the structure and dynamical functioning of basal ganglia motor control networks involved in tremor generation.