bluuebunny/crossref_metadata_2025 huggingface dataset:
Effect of a fibrolytic enzyme preparation from Trichoderma longibrachiatum on the rumen microbial population of dairy cows
Authors: Nsereko V L , Beauchemin K A , Morgavi D P , Rode L M , Furtado A F , McAllister T A , Iwaasa A D , Yang W Z , Wang Y.
Published: July 2002

The effects of supplementing a dairy cow diet with incremental levels of a fibrolytic enzyme preparation (preparation B) from Trichoderma longibrachiatum on the rumen microbial population were investigated. Two cows fitted with rumen cannulae were each fed a diet containing barley-based concentrate (52%), maize silage (29%), and chopped alfalfa hay (19%), supplemented with 0, 1, 2, 5, or 10 L of preparation B per tonne of dry matter (DM). Preparation B stimulated numbers of total viable bacteria in a quadratic manner (P < 0.05), to approximately 230, 330, 390, and 250% at 1, 2, 5, and 10 L·t1 DM, respectively. Preparation B increased the numbers of cellobiose-utilizing (P < 0.01), xylanolytic (P < 0.05), and amylolytic bacteria (P < 0.05), but had no effect (P > 0.05) on numbers of cellulolytic bacteria. However, when bacterial numbers enumerated on each substrate were expressed as a proportion of total viable bacterial numbers, only cellobiose utilizers were stimulated, and this stimulation was limited to the 1 L·t1 DM level of preparation B (P < 0.05). The results of this study demonstrate that the inclusion of an exogenous fibrolytic enzyme preparation in dairy cow diets increased the numbers of rumen bacteria that utilize hemicelluloses and secondary products of cellulose digestion.Key words: rumen, fibrolytic enzymes, cellulase, xylanase, cellulolytic, xylanolytic.
Evaluation of probability proportional to predictions estimators of total stem volume
Authors: Magnussen Steen
Published: July 2002

A plethora of probability proportional to predictions (PPP) estimators makes it hard for a user to decide which one to use. This study demonstrates the need for an extensive screening procedure by example of four PPP estimators of total stem volume and five estimators of sampling error. Bias, absolute bias, root mean square error, sample-based estimators of sampling error, and achieved significance levels of confidence intervals with a nominal significance level were compared across 832 distinct settings. Population size, sample size, the variance and skewness of the volume predictors, and the strength of the correlation and the slope between predicted and actual stem volume varied between settings. Estimators converged in performance as sample sizes increased but were otherwise sensitive to actual settings. Of the tested estimators, Brewer's "cosmetically calibrated" estimator was consistently the best in terms of mean absolute relative bias and generally favored in an overall assessment of five performance criteria. Grosenbaugh's adjusted estimator was a close second and was often ranked first in overall performance when n > 0.15N.
Prediction of forest stem volume using kriging adapted to detected edges
Authors: Wallerman Jörgen , Joyce Steve , Vencatasawmy Coomaren P , Olsson Håkan
Published: July 2002

The modern techniques of the global positioning system and geographic information system enable many new approaches to forestry planning problems. Using these it is possible to efficiently geoposition, store, and analyze each field measurement in a spatial context. This work is directed towards the application of a dynamic forestry planning system based on a forest map with very high spatial resolution created from geopositioned field plot data, instead of the traditional forest stand map. The new dynamic system is dependent on accurate methods to create a high-resolution map from a set of field measurements. This problem may be solved using the kriging spatial prediction (interpolation) method. The aim of this paper is to present and empirically evaluate a new kriging method side-by-side with global and stratified kriging. The new method uses the output from an edge-detection algorithm, here applied to Landsat TM image data, to increase the prediction accuracy. Prediction evaluation was made in terms of mean forest stem volume per hectare measured on circular field plots of 10 m radius. The new method showed a prediction root mean square error of 41% of the mean volume, compared with corresponding results of global, 58%, and stratified kriging, 45%.
SIMULATION OF HIERARCHICAL RESOURCE MANAGEMENT FOR META-COMPUTING SYSTEMS
Authors: SANTOSO J. , VAN ALBADA G. D. , SLOOT P. M. A. , NAZIEF B. A. A.
Published: July 2002

Optimal scheduling in meta-computing environments still is an open research question. Various resource management (RM) architectures have been proposed in the literature (e.g. [2][13][12]). In the present paper we explore, through simulation, various multi-level scheduling strategies for compound computing environments comprising several clusters of workstations. We study global and local RM and their interaction. The local RM comprises both the cluster management and operating system schedulers. Each level refines the scheduling decisions of the layer above it, taking into account the latest resource information. Our experiments explore conventional strategies like First Come, First Served (FCFS) and Shortest Job First (SJF) at the global RM level. At all levels, the schedulers strive to maintain a good load balance. The unit of load balancing at the global level is the job consisting of one or more parallel tasks; at the local level it is the task. The results of our simulations indicate that, especially at high system loads, the use of a global RM can result in a significant performance gain.
STICKY SPHERES IN QUANTUM MECHANICS
Authors: PENROSE M. D. , PENROSE O. , STELL G.
Published: July 2002

For a 3-dimensional system of hard spheres of diameter D and mass m with an added attractive square-well two-body interaction of width a and depth ε, let BD, a denote the quantum second virial coefficient. Let BD denote the quantum second virial coefficient for hard spheres of diameter D without the added attractive interaction. We show that in the limit a → 0 at constant α: = ℰma2/(2ħ2) with α < π2/8, [Formula: see text] The result is true equally for Boltzmann, Bose and Fermi statistics. The method of proof uses the mathematics of Brownian motion.

For α > π2/8, we argue that the gaseous phase disappears in the limit a → 0, so that the second virial coefficient becomes irrelevant.
On the Structure of Monodromy Algebras and Drinfeld Doubles
Authors: Nill Florian
Published: July 2002

We give a review and some new relations on the structure of the monodromy algebra (also called loop algebra) associated with a quasitriangular Hopf algebra H. It is shown that as an algebra it coincides with the so-called braided group constructed by S. Majid on the dual of H. Gauge transformations act on monodromy algebras via the coadjoint action. Applying a result of Majid, the resulting crossed product is isomorphic to the Drinfeld double [Formula: see text]. Hence, under the so-called factorizability condition given by N. Reshetikhin and M. Semenov–Tian–Shansky, both algebras are isomorphic to the algebraic tensor product H ⊗ H. It is indicated that in this way the results of Alekseev et al. on lattice current algebras are consistent with the theory of more general Hopf spin chains given by K. Szlachányi and the author. In the Appendix the multi-loop algebras ℒm of Alekseev and Schomerus [3] are identified with braided tensor products of monodromy algebras in the sense of Majid, which leads to an explanation of the "bosonization formula" of [3] representing ℒm as H ⊗…⊗ H.
Introduction to Quantum Groups
Authors: Podleś P. , Müller E.
Published: July 2002

We give an elementary introduction to the theory of algebraic and topological quantum groups (in the spirit of S. L. Woronowicz). In particular, we recall the basic facts from Hopf (*-) algebra theory, theory of compact (matrix) quantum groups and the theory of their actions on compact quantum spaces. We also provide the most important examples, including the classification of quantum SL(2)-groups, their real forms and quantum spheres. We also consider quantum SLq(N)-groups and quantum Lorentz groups.
VARIABLE-COEFFICIENT BALANCING-ACT ALGORITHM EXTENDED TO A VARIABLE-COEFFICIENT MKP MODEL FOR THE ROTATING FLUIDS
Authors: GAO YI-TIAN , TIAN BO
Published: July 2002

The modified Kadomtsev–Petviashvili (MKP) models describe the large-scale motion of such rotating fluids as the atmosphere and oceans. Based on the computerized symbolic computation, we in this paper extend the power of the variable-coefficient balancing-act method, which is recently proposed, to a variable-coefficient MKP model. The model is re-written as a coupled set of partial differential equations, and the algorithm is re-written correspondingly. We obtain a new family of the soliton-like, exact analytic solutions, beyond the traveling waves.
ABRAHAMS–TSUNETO REACTION–DIFFUSION SYSTEM IN SUPERCONDUCTIVITY AND SYMBOLIC COMPUTATION
Authors: GAO YI-TIAN , TIAN BO , WEI GUANG-MEI
Published: July 2002

The reaction–diffusion systems represent various problems in the real world. For the Abrahams–Tsuneto reaction–diffusion system arising in superconductivity, we perform computerized symbolic computation and find its new exact analytic solutions, which are solitonic. We see the possibility that by way of the shock waves, the self–consistent superconducting interaction drives the Ginzburg–Landau order parameter, which might be observable.
ANTICIPATORY DRIVERS IN THE NAGEL–SCHRECKENBERG-MODEL
Authors: SCHNEIDER JOHANNES , EBERSBACH ANJA
Published: July 2002

The Nagel–Schreckenberg-model (NaSch-model) describes macroscopic features of real traffic very well. However, the characterization of a single car driver's behavior in some details is not realistic, e.g., the NaSch-driver calculates his/her distance to the car in front from the position this car has just in the very moment and ignores that it could move further in the next time step. This behavior is rarely found in real traffic. Normally, a driver estimates the speed of the car in front, takes as well a certain braking distance into consideration and keeps distance accordingly. As an answer to this demand, the second rule of the NaSch-model is modified in the following.
QUANTUM KEY-DISTRIBUTION PROTOCOL FOR N-BIT SECRET MESSAGE COMMUNICATION
Authors: PAN FENG , DAI LIAN-RONG , DRAAYER J. P.
Published: July 2002

Possible schemes for sending N-bit secret message with established N EPR pairs and a classical channel between two parties, are considered. The corresponding N-particle quantum key-distribution for N-bit secret message communication is outlined.
AUTOMATIC PARALLELIZATION TECHNIQUES BASED ON COMPACT DAG EXTRACTION AND SYMBOLIC SCHEDULING
Authors: COSNARD MICHEL , JEANNOT EMMANUEL
Published: July 2002

Symbolic allocation and dynamic scheduling of tasks on a distributed memory machine for coarse-grained applications represented by parameterized task graphs (PTG) are presented in this paper. A PTG is a new computation model for symbolically representing directed acyclic task graphs (DAGs). The size of a PTG is independent of the problem size and its parameters can be instantiated at run time. Parameter independent optimization is important for exploiting non-static parallelism in scientific computing programs with varying problem sizes. Previous DAG scheduling algorithms are not able to handle such cases. We present and study a symbolic scheduling algorithm called SLC (Symbolic Linear Clustering) which derives task clusters from a PTG using affine piecewise mapping functions and then evenly assigns clusters to processors. Thus a complete automatic parallelization method is presented.
ONE-LOOP ANALYSIS OF QCD STRINGS WORLD SHEETS IN ℝ4 THROUGH A WEIERSTRASS-TYPE REPRESENTATION
Authors: KONOPELCHENKO B. G. , LANDOLFI G.
Published: July 2002

Rigid string world sheets in ℝ4 are described by means of a representation of the Weierstrass type. Correlators for the full rigid string action in the one-loop approximation over minimal backgrounds are calculated.
HIGH-PRECISION ESTIMATES OF CRITICAL QUANTITIES BY MEANS OF IMPROVED HAMILTONIANS
Authors: CAMPOSTRINI MASSIMO , ROSSI PAOLO , VICARI ETTORE , HASENBUSCH MARTIN , PELISSETTO ANDREA
Published: July 2002

Three-dimensional spin models of the Ising and XY universality classes are studied by a combination of high-temperature expansions and Monte Carlo simulations applied to improved Hamiltonians. The critical exponents and the critical equation of state are determined to very high precision.
AN OBSERVATION OF AUTOCORRELATION OF WILSON LOOPS ON LATTICE
Authors: LIU DA QING , CHEN YING , WU JI MIN
Published: July 2002

An observation of the autocorrelation of Wilson loops on lattice is presented, especially for the small separation in Markov chain. We give a possible explanation for such behavior. We also present the dependence of autocorrelation behavior on the chosen operators in this paper.
ON THE SIZE OF HADRONS
Authors: PAULI HANS-CHRISTIAN , MUKHERJEE ASMITA
Published: July 2002

The form factor and the mean-square radius of the pion are calculated analytically from a parametrized form of a [Formula: see text] wave function. The numerical wave function was obtained previously by solving numerically an eigenvalue equation for the pion in a particular model. The analytical formulas are of more general interest than just being valid for the pion and can be generalized to the case with unequal quark masses. Two different parametrizations are investigated. Because of the highly relativistic problem, noticeable deviations from a nonrelativistic formula are obtained.
Electro-optical measurements of ultrashort 45 MeV electron beam bunch
Authors: Nikas D. , Castillo V. , Kowalski L. , Larsen R. , Lazarus D. M. , Ozben C. , Semertzidis Y. K. , Tsang T. , Srinivasan-Rao T.
Published: July 2002

We have made an observation of 45 MeV electron beam bunches using the nondestructive electro-optical (EO) technique. The amplitude of the EO modulation was found to increase linearly with electron beam charge and decrease inversely with the optical beam path distance from the electron beam. The risetime of the signal was bandwidth limited by our detection system to ~ 70 ps. An EO signal due to ionization caused by the electrons traversing the EO crystal was also observed. The EO technique may be ideal for the measurement of bunch structure with femtosecond resolution of relativistic charged particle beam bunches.
THE SPECTRUM OF DIQUARK COMPOSITES IN COLD DENSE QCD
Authors: SHOVKOVY IGOR
Published: July 2002

The Bethe-Salpeter equations for spin zero diquark composites in the color superconducting phase of Nf = 2 and Nf = 3 cold dense QCD are studied. The explicit form of the spectrum of the diquarks with the quantum numbers of the (pseudo-) Nambu-Goldstone bosons is derived.
DYNAMICAL EVOLUTION OF CLUSTERS OF GALAXIES: THE EFFECT OF HIGH-VELOCITY SUBSTRUCTURE CLUMPS
Authors: DEL POPOLO A. , GAMBERA M. , NIHAL ERCAN E.
Published: July 2002

In the Cold Dark Matter (hereafter CDM) scenario even isolated density peaks contain a high fraction of small scale clumps having velocities larger than the average escape velocity from the structure. These clumps populate protoclusters, especially in the peripheral regions, r≥R f (where R f is the filtering scale). During the cluster collapse and the subsequent secondary infall, collapsing or infalling clumps (having vv esc . We study the interaction between these two kinds of clumps by means of the impulse approximation1 and we find that the collapse of bound clumps is accelerated with respect to the homogeneous case (Gunn and Gott's model, Ref. 2). The acceleration of the collapse increases with decreasing height of the peak, ν. We finally compare the acceleration produced by this effect to the slowing down effect produced by the gravitational interaction of the quadrupole moment of the system with the tidal field of the matter of the neighboring proto-clusters studied by Del Popolo and Gambera.3 We find that the magnitude of the slowing down effect is larger than the acceleration produced by the effect studied in this paper, only in the outskirts of the cluster. We want to stress that the one which we study in this paper is also present in an isolated protocluster, being produced by the interaction of the collapsing clumps with the unbound substructure internal to the collapsing clumps itself while that studied in Ref. 3 is produced by substructure external to the density peak.
DIRECT RG-IMPROVEMENT OF THE HIGGS MASS
Authors: AL-NAGHMOUSH ALI , AL-THOYAIB SULEIMAN S. , TAHA M. O.
Published: July 2002

We write the renormalization group equation for the Higgs mass mH and use it to improve calculations of mH in the standard model. This improvement changes the results considerably and should be taken into account in a reliable calculation. Our numerical results give the upper bound mH≤173 GeV under the condition that the effective potential is real at its absolute minimum. This result is in agreement with recent experimental and theoretical estimates.
QUANTUM FLUCTUATION AND REVIVAL OF SUPERCURRENT IN MESOSCOPIC JOSEPHSON JUNCTION DRIVEN BY CLASSICAL PERIODIC FIELD
Authors: LI QIANSHU , SHAO BIN , ZOU JIAN , WANG RONGYAO
Published: July 2002

We examine an effective bosonic Hamiltonian describing a mesoscopic Josephson junction driven by a sinusoidal magnetic field. We study the effects caused by the Josephson nonlinearity and find that an initial vacuum state of the junction can evolve into a class of superposition state of coherent states. Further, we investigate the reduced quantum fluctuation of the junction variables and the dynamics of the supercurrent. Our results show that, due to the effect of Josephson nonlinearity, the time evolution of the supercurrent can exhibit the collapse and revival even when the junction is driven by a classical field.
CORE LEVEL CHEMICAL SHIFTS AND LINE SHAPES FOR SYSTEMS WITH DIFFERENT VALENCIES AND Cu-O NETWORKS
Authors: KARLSSON K. , GUNNARSSON O. , JEPSEN O.
Published: July 2002

We have studied the Cu -2p core level photoemission spectrum of a variety of cuprates, mainly focusing on the chemical shift and the shape of the leading peak. The spectra are calculated using the Anderson impurity model and we obtain a very good agreement with the experimental data. We find that the shape of the leading peak depends crucially on the structure of the Cu - O network. The main peak turns out to be quite narrow if the network consists of Cu - O - Cu bond angels of the order of 90°. On the other hand, if the Cu - O atoms are arranged with bond angles of approximately 180°, the main peak becomes substantially broader and contains a rather complicated structure. However, in some cases it is not sufficient only to consider the Cu - O network because interactions with other atoms are also important. In the model compounds Cu 2 O , CuO and NaCuO 2, where Cu is formally monovalent, divalent and trivalent, respectively, we find that the number of 3d electrons is rather similar. Nevertheless, the binding energy increases with the valence as expected from chemical intuition. The spectra exhibit a large variation in the strength of the d9-like satellite and in the width of the main line. We, furthermore, study the chemical shift of three inequivalent Cu atoms in YBa 2 Cu 3 O 6.5, and compare the results with the model compounds, which suggests that the different Cu atoms in YBa 2 Cu 3 O 6.5 have formal valences of approximately one, two and three. These findings are analyzed and related to the formal valence.
MAGNETIC MEASUREMENTS OF HIGH QUALITY SINGLE CRYSTAL YBa2Cu3O7-δ
Authors: TIRBIYINE A. , TAOUFIK A. , SENOUSSI S.
Published: July 2002

We have investigated the magnetic measurements on high quality single crystals of YBa 2 Cu 3 O 7-δ. Several magnetization hysteresis loops have been obtained for different temperature values, and as a function of the angle θ between the direction of the applied magnetic field and the c-axis of the sample. Measurements were performed at magnetic field up to 6 Tesla and various temperatures between 10 and 90 K. Magnetization hysteresis loops scale and shape are strongly dependent on the temperature values. Our results show that the magnetic properties are profoundly affected by flux lines pinning. The irreversible magnetization decreases as the applied magnetic field deviates from the c-axis (θ increases).
SMALL-TO-LARGE POLARON CROSSOVER IN ONE DIMENSION USING VARIATIONAL PHONON-AVERAGING TECHNIQUES
Authors: CHOUDHURY P. , DAS A. N.
Published: July 2002

The ground-state properties of polarons in a one-dimensional chain is studied analytically within the modified Lang–Firsov (MLF) transformation using various phonon-averaging techniques. The object of the work is to examine how the analytical approaches may be improved to give rise to the real picture of polaronic properties as predicted by extensive numerical studies. The results are compared with those obtained from numerical analyses using the density matrix renormalization group (DMRG) and other variational techniques. It is observed that our results agree well with the numerical results particularly in the low and intermediate range of phonon coupling.
A CONVERGENT PERTURBATION METHOD FOR THE HOLSTEIN MODEL AND ITS APPLICATION TO THE DOUBLE EXCHANGE SYSTEM
Authors: DAS A. N. , CHATTERJEE JAYITA , MITRA M.
Published: July 2002

We look for an analytical method which can describe the Holstein model over the entire region of electron–phonon (e–ph) coupling strength. Considering a toy model of two sites the perturbation expansions are developed for the Holstein Hamiltonian using different standard phonon bases. It is found that the modified Lang Firsov phonon basis shows satisfactory convergence for almost the entire range of e–ph coupling from the antiadiabatic limit to the intermediate range of hopping. This method is used to study the magnetic transition and the small to large polaron crossover in a double exchange model with e–ph interaction. Implications of the results in the context of manganites are discussed.
INFLUENCE OF TRANSLATIONAL SYMMETRY OF FERROMAGNETIC SUPERLATTICES IN THE STUDY OF ELEMENTARY EXCITATIONS
Authors: PAVKOV M. , ŠKRINJAR M. , KAPOR D. , PANTIĆ M. , STOJANOVIĆ S.
Published: July 2002

Elementary excitations in ferromagnetic superlattices are analyzed theoretically using the transfer matrix method. The method is extended to enable the study of the cases when the boundaries are not consisting of a single plane, but of a complete cell. In this way, semi-infinite superlattice, the interface between two superlattices and the film built of a superlattice are treated. However, it is shown that the choice of the transfer matrix strongly depends on the translational symmetry of the remaining part of the system. Energies of localized excitations are derived and compared both with bulk and the results of standard transfer matrix treatment proposed by Barnas. Also, a special Ansatz for spin amplitudes is proposed leading to identical results with the transfer matrix method and introducing large simplifications.
MODELS OF PARACRYSTALLINE SILICON WITH A DEFECT-FREE BANDGAP
Authors: NAKHMANSON S. M. , MOUSSEAU N. , BARKEMA G. T. , VOYLES P. M. , DRABOLD D. A.
Published: July 2002

Recently there have been attempts to create physically realistic models for para/poly-crystalline silicon (containing randomly oriented c-Si grains embedded in a disordered matrix) by means of empirical molecular dynamics. These models demonstrate acceptable geometrical and vibrational properties but fail to reproduce the correct electronic bandgap due to the presence of numerous "frozen-in" coordination defects. We propose a new procedure for the preparation of more realistic models of paracrystalline silicon based on a modification of the bond-switching method of Wooten, Winer and Weaire. Our new method allows us to create interfaces between the crystalline and disordered phases of Si with no coordination defects. Models with 400, 1000, and 4000 atoms were constructed. All the models have ~10 atomic % of the crystalline phase. The two smaller models contain a single crystalline grain and the largest model contains 4 randomly oriented grains. Our models show good geometrical and vibrational properties compared to good continuous random networks models of a-Si and also display excellent optical properties, correctly reproducing the electronic bandgap of amorphous silicon.
Nanostructured Organic Thin Films: Electronic Energetics and Devices
Authors: TALIANI C. , BISCARINI F. , LUNEDEI E. , Mei P. , Muccini M. , Murgia M. , Schneider M. , Lanzani G.
Published: July 2002

We report on the optoelectronic properties of vacuum sublimed organic thin films of the oligothienyls ( Tn ) model systems. The Davydov splitting (DS) of the lowest exciton is about 0.3 eV and decreases with the conjugation length when going from T 4 to T 6. The lowest DS component is partially forbidden due to the crystal packing and the spectral activity occurs via Herzberg-Teller (HT) vibronic coupling. We show the real time dynamics of the HT coupling by coherent vibrational spectroscopy and the role of aggregates in the energy transfer processes within the films.
SPECTROSCOPIC PROPERTIES OF SELECTIVELY DEUTERIUM-SUBSTITUTED RETINAL HOMOLOGUES
Authors: YAMAMOTO TAKAYUKI , ABE MOTOYA , YAMADA TAKASHI , HASHIMOTO HIDEKI , KOBAYASHI TAKAYOSHI
Published: July 2002

A set of retinal homologue molecules (C15 aldehyde, C17 aldehyde, C18 ketone, C20 aldehyde) in which 11H or 15H atom of their olefinic parts was selectively substituted by a deuterium (11D or 15D) was synthesized. Their spectroscopic properties were investigated by means of optical obsorption and FT-IR spectroscopies. Normal coordinate calculations were performed for all the set of molecules in order to establish the assignment of vibrational modes. Upon deuterium substitution of the 11H or 15H atom, apparent decrease of the oscillator-intensity of the absorption transition was observed in the case of shorter polyene molecules (C15 and C17aldehydes and C18ketone), while the decrease of the oscillator strength was negligible in the case of C20 aldehyde. Vibrational analysis suggested that the selective deuterium substitution induced the shift of electron distribution from double-bond site to single-bond site resulting in the decrease and increase in the bond orders of the former and the latter, respectively.
ION SELECTIVITY DURING FORMATION OF PASSIVE FILMS ON STAINLESS STEELS AND ALLOYS
Authors: QIU J. H.
Published: July 2002

The stability of stainless steels and allied materials is essentially determined by the integrity of naturally formed ultra thin oxide films – the passive films on their surfaces. The thickness of such an ultra thin film for a typical stainless steel (AISI 304) is about 2 nm. The compositions of passive films are totally different from those of the underlying substrates. During the film formation process, ion selectivity occurs both at the solid/liquid and metal/oxide interfaces. Using advanced surface and solution analytical techniques such as X-ray Photoelectron Spectroscopy (XPS) and Inductively-Coupled Plasma source Mass Spectroscopy (ICP-MS), it is possible analyse the ion selectivity at the solid/liquid and metal/oxide interfaces. It was observed that at the solid/liquid interface, elements such as iron and nickel were selectively leached into the liquid phase, leading to a surface enriched with other alloying elements such as chromium and molybdenum. There exists a good linear relationship between the selectivity factor and passivation time.
THE IMPURITY EFFECTS ON GROWTH, STRUCTURE AND PHYSICAL PROPERTIES OF STRONTIUM NITRATE CRYSTALS
Authors: LI CHAORONG , WU LIJUN , CHEN WANCHUN
Published: July 2002

The effects of Ba 2+ and Pb 2+ impurities on the crystal growth, structure and physical properties of Sr ( NO 3)2 crystal have been investigated. The in situ crystal growth observations show that in pure or Pb 2+ doped solutions the crystal growth rate on {100} surfaces is larger than that on {111} surfaces, that is R100 > R111, in the low supersaturation region, while R100 < R111 in the higher supersaturation region. However, in the case of Ba 2+ doped crystals, the scenario was reversed. Therefore, the doping of Ba 2+ will influence the crystal growth morphology of the strontium nirate crystals. Composition distribution show that the Ba 2+ ions were enriched in the {100} growth sectors, while Pb 2+ ions were enriched in {111} sectors. The impurities will deteriorate the crystalline quality from the high resolution x-ray diffraction results. Raman dominating peaks of the Ba 2+ or Pb 2+ doped Sr ( NO 3)2 crystals will be shifited to lower frequencies and the shifting value depends on impurity composition.
CALCULATION OF THE FLUX ASSOCIATED WITH THE ELECTRON'S SPIN ON THE BASIS OF THE MAGNETIC TOP MODEL
Authors: SAGLAM M. , BOYACIOGLU B.
Published: July 2002

The flux associated with the electron's spin is calculated on a the basis of the magnetic top (spherical top) model which can be made equivalent to a circular current loop with radius R in x–y plane in the presence of a uniform magnetic field in z-direction. It is found that the flux associated with the electron's spin is exactly equal to +Φ0/2 for a spin down electron and -Φ0/2 spin up one.
STUDY OF QUANTUM CURRENT ENHANCEMENT, EIGENENERGY SPECTRA AND MAGNETIC MOMENTS IN A MULTIPLY CONNECTED SYSTEM AT EQUILIBRIUM
Authors: BENJAMIN COLIN , JAYANNAVAR A. M.
Published: July 2002

A multiply connected system in both its open and closed form variations but in equilibrium is studied using quantum waveguide theory. The system exhibits remarkable features, in its open form variation we see current enhancement, hitherto seen only in non-equilibrium systems in absence of magnetic flux. In its closed form analog parity effects are broken. Further we analyse the global and local current densities of our system and also show that the orbital magnetic response of the system calculated from the current densities (and inherently linked to the topological configuration) is qualitatively not same as that calculated from the eigenenergy spectra.
MICROSTRUCTURE AND ELECTROCHEMICAL BEHAVIOR OF SPUTTERED DIAMOND-LIKE CARBON FILMS
Authors: ZENG A. , LIU E. , HING P. , ZHANG S. , TAN S. N. , ANNERGREN I. F. , GAO J.
Published: July 2002

Diamond-like carbon (DLC) films with different structure were deposited on highly electrically conductive silicon substrates (SiO2/Si), using dc magnetron sputtering deposition process. Their structure and electrochemical behavior in 0.5 M H 2 SO 4 solution were studied with micro-Raman spectroscopy, electrochemical impedance spectroscopic (EIS) analysis and film impedance. The double layer capacitance on the DLC films was about 0.571 - 3.91 μ F-cm -2. The capacitance increased with the increased Raman spectrum intensity ratio I D / I G and accelerated at around 2.25 of the ratio. The results suggest that the potential of DLC films as electrode materials for electrochemical analysis.
RIGOROUS RESULTS ON THE STRONGLY CORRELATED ELECTRON SYSTEMS BY THE SPIN-REFLECTION-POSITIVITY METHOD
Authors: TIAN GUANG-SHAN
Published: July 2002

In this talk, we shall briefly review some results on the strongly correlated electron systems, derived recently by applying Lieb's spin-reflection-positivity method. To explain the basic ideas of this method to a wide audience, we emphasize the important role played by Marshall's rule in studying the many-body systems.
FREE FIELD AND PARAFERMIONIC REALIZATIONS OF TWISTED $su(3)^{(2)}_k$ CURRENT ALGEBRA
Authors: DING XIANG-MAO , GOULD MARK D. , ZHANG YAO-ZHONG
Published: July 2002

Free field and twisted parafermionic representations of twisted [Formula: see text] current algebra are obtained. The corresponding twisted Sugawara energy-momentum tensor is given in terms of three (β,γ) pairs and two scalar fields and also in terms of twisted parafermionic currents and one scalar field. Two screening currents of the first kind are presented in terms of the free fields.
A NOTE ON (SPIN-) COHERENT-STATE PATH INTEGRAL
Authors: SHIBATA JUNYA , TAKAGI SHIN
Published: July 2002

It is pointed out that there are some fundamental difficulties with the frequently used continuous-time formalism of the spin-coherent-state path integral. They arise already in a single-spin system and at the level of the "classical action" not to speak of fluctuations around the "classical path". Similar difficulties turn out to be present in the case of the (boson-)coherent-state path integral as well; although partially circumventable by an ingenious trick (Klauder's ∊-prescription) at the "classical level", they manifest themselves at the level of fluctuations. Detailed analysis of the origin of these difficulties makes it clear that the only way of avoiding them is to work with the proper discrete-time formalism. The thesis is explicitly illustrated with a harmonic oscillator and a spin under a constant magnetic field.
EFFECTIVE FIELD THEORY APPROACH TO FERROMAGNETS AND ANTIFERROMAGNETS IN CRYSTALLINE SOLIDS
Authors: ROMÁN JOSÉ MARÍA , SOTO JOAN
Published: July 2002

We present a systematic construction of effective Lagrangians for the low energy and momentum region of ferromagnetic and antiferromagnetic spin waves in crystalline solids. We fully exploit the spontaneous symmetry breaking pattern SU(2)→U(1), the fact that spin waves are its associated Goldstone modes, the crystallographic space group and time reversal symmetries. We show how to include explicit SU(2) breaking terms due to spin-orbit and magnetic dipole interactions. The coupling to electromagnetic fields is also discussed in detail. For definiteness we work with the space group [Formula: see text] and present our results to next to leading order.
OPTIMIZATION OF LASER ABLATED ALUMINUM PLASMAS USING CHARGE COLLECTOR
Authors: MISRA A. , SRIVASTAVA T. , THAREJA R. K.
Published: July 2002

We report on the studies of the behavior of plasma species in an expanding plasma using charge collector. A Faraday cup was designed and used to measure the time of flight distribution of the positive ions in a laser produced aluminum plasma at low and moderate laser intensities. The effect of grid voltage and the dynamics of the charged particles in an ablated plume are discussed.
Electrorheology of Suspensions of Si Particles with an Oxide Film in Silicone Oil
Authors: Wu C. W. , Conrad H.
Published: July 2002

The electrorheological (ER) behavior of suspensions of oxidized Si partices in silicone oil was determined with dc electric field E 0. The yield stress decreased with the thickness of the surface oxide film and was proportional to E01.7 when the surface film thickness δ=0.2 μ m . The current density and the field dependent exponent decreased with the surface film thickness. When the surface film thickness δ=0.05μ m , the current density was proportional to E001.3. The results are in accord with our recent non-ohmic conduction model for the influence of an oxide film on conducting particles on ER response. The ER response of highly conducting particles with a low conductivity coating with ac field is also discussed.
ON THE INTERACTION ENERGY OF TWO-DIMENSIONAL ELECTRON FQHE SYSTEMS WITHIN THE CHERN–SIMONS APPROACH
Authors: SITKO PIOTR
Published: July 2002

The interaction energy of the two-dimensional electron system in the region of fractional quantum Hall effect is considered within the Chern–Simons composite fermion approach. In the limit when Coulomb interaction is very small comparing to the cyclotron energy the RPA results are obtained for the fillings ν=1/3, 1/5, 2/3, 2/5, 3/7 and compared with the exact diagonalization results for small systems (extrapolated for infinite systems). They show very poor agreement suggesting the need for looking for alternative approaches.
QUANTUM MEASUREMENTS, INFORMATION AND ENTROPY PRODUCTION
Authors: SRIVASTAVA Y. N. , VITIELLO G. , WIDOM A.
Published: July 2002

In order to understand the Landau–Lifshitz conjecture on the relationship between quantum measurements and the thermodynamic second law, we discuss the notion of "diabatic" and "adiabatic" forces exerted by the quantum object on the classical measurement apparatus. The notion of heat and work in measurements is made manifest in this approach and the relationship between information entropy and thermodynamic entropy is explored.
NON-LINEARITY AND ANISOTROPY OF ELECTRON-PHONON COUPLING IN HIGH-Tc OXIDES
Authors: Santi G. , Jarlborg T.
Published: July 2002

The calculated electronic structures of YBa 2 Cu 3 O 7, HgBa 2 CuO 4 and Bi 2 Sr 2 CaCu 2 O 8 are found to be sensitive to lattice distortions. For large distortion amplitudes of some modes, the calculations show that the electron-phonon coupling (λ) will be much enhanced, so that the coupling behaves non-linearly with the distortion. The c-axis transport properties vary with the distortion from being almost insulating and thereby weakly screened, to being more conducting with rather metallic screening. The calculated anisotropy λ(k,k′) over the Fermi surface (FS) of the Hg-compound, is found to be of "forward scattering" type, which is favorable for d-wave superconductivity.
MAGNETIC SUSCEPTIBILITY INVESTIGATION OF NiO–Bi2O3–GeO2 GLASSES
Authors: ARDELEAN I.
Published: July 2002

Magnetic susceptibility investigations of x NiO · (1 - x)[ Bi 2 O 3 · GeO 2] glasses with 0 < x ≤ 40 mol% are reported. The effective magnetic moment values suggest that the Ni 2+ ions are predominantly tetrahedral coordinated in low NiO content glasses, whereas in higher NiO content glasses the Ni 2+ ions are located in octahedral sites. Also, paramagnetic Curie temperatures indicate that the Ni 2+ ions participate at the superexchange interaction of the antiferromagnetic type for x > 10 mol% .
WIGNER LATTICE ORDER, COLLECTIVE MODE, AND SUPERCONDUCTIVITY IN THE La1.985Sr0.015CuO4+δ SYSTEM
Authors: KIM YOUNG HOON , HOR PEI HERNG
Published: July 2002

We have studied far-infrared charge dynamics of Sr- and O- co-doped La 1.985 Sr 0.015 CuO 4+δ with δ = 0.024 (p = 0.063 per Cu) and δ = 0.032(p = 0.07). We found that two-dimensional Wigner lattice order is the ground state of cuprates away from half-filling. We found that the presence of 2D Wigner lattice and the pinned Goldstone mode is essential for cuprate physics and superconductivity. We propose that all high T c physics are based on the existence of these peculiar 2D electron lattices.
INFLUENCE OF THE LATTICE MISMATCH ON THE PHOTOLUMINESCENCE BAND-TAIL PARAMETER IN InGaAsP/InP HETEROSTRUCTURES
Authors: IRIBARREN A.
Published: July 2002

The compositional inhomogeneities in semiconductor heterostructures leads to diminishing the quality of the grown layer which reflects in the shape of the rocking curves, where the full width at half maximum (FWHM) of the peaks is larger. Consequently, the quality of the layers characterized by an increase of the disorder also reflects in the band-tail parameter ( E 0) of the photoluminescence spectra. A linear dependence of the FWHM with the lattice mismatch (Δa) was found. The dependence of E 0 as a function of FWHM are presented. It was found that E 0 keep constant up to Δ a / a ≅ 0.15% and FWHM ≅ 50" from where it begins to increase.
INVESTIGATION OF SELF-ORGANIZATION PROCESSES IN SEMICONDUCTOR UNDER PHOTO-GUNN EFFECT
Authors: GONZÁLEZ-HERNÁNDEZ J. , VOROBIEV YU .V. , HORLEY P. P. , GORLEY P. M.
Published: July 2002

In the given paper, the results are presented of the investigation of non-equilibrium stationary carriers system in semiconductor under photo-Gunn effect. It was found that space-homogeneous state of the system is unstable in the case of negative differential conductivity and two waves of space-time perturbations with different phase velocities propagate through the crystal. Phase velocity degeneration conditions have been determined for these waves. Dependence of the complex attenuation decrement on external influences (electric field tension, incident light intensity, semiconductor compensation degree and spectral range) has been investigated in details. State dynamics of inhomogeneous carrier system has been studied using synergetics methods. Obtained results prove that one can controllably switch between the oscillation states of electron subsystem by changing the incident light intensity.
Thermal Characterization and Crystal Structure of an Electrorheological Material — Complex Strontium Titanate
Authors: Zhang Yuling , Ma Yong , Liang Jingkui , Rao Guanghui , Lu Kunquan
Published: July 2002

A new type of anhydrous complex strontium titanate (STO) electrorheological fluid (ERF) material is obtained, which demonstrates a good electrorheological (ER) character even at lower applied electric field. Its shear stress is about 8~kPa at electric field of 2.4 kV/mm. The current density is only 1.6 μA/cm2 leaking through the fluids. Some additive in our samples prevents sedimentation. The shear stresses vary only slightly in a wide temperature range. The thermal characteristics of the solid phase STO including the heat capacity and thermal stability were investigated. The value of the activation energy of crystallization was derived to be about 100 kJ/mole. The crystal structure of Y-doped STO was refined by the Rietveld method. Y 3+ substitutes for Sr 2+ in the 1(a) position of space group Pm3m.
STUDY ON THE INTERFACE STRUCTURE: DIAMOND THIN FILM EPITAXY ON (001) SILICON SUBSTRATE
Authors: MENG Q. B. , FEI Y. J. , KANG J. , XIONG Y. Y. , LIN Z. D. , FENG KE-AN , WU Z. J. , ZHANG S. Y.
Published: July 2002

An interesting interface structure between diamond film and silicon substrate has been observed. That is, according to the deformation of the diamond film crystal structure, a strictly 3:2 matching of the two lattices across the interface is obtained. This result clearly indicates that misfit dislocations at the interface and "epitaxial tilting" are not the only two ways to overcome the 1.5% residual misfit.
NUMBER-PHASE WIGNER FUNCTION FOR THE FIELD STATE OF A TWO-PHOTON JAYNES–CUMMINGS MODEL
Authors: JOSHI AMITABH , DUNG HO TRUNG
Published: July 2002

The number-phase Wigner function W NP (defined in Refs. 3 and 4) has been studied for the field state of a two-level atom undergoing two-photon transition in a single mode field sustained in an ideal cavity. The photon number and the phase observables are graphically represented by this function W NP and thus their complementarity can be directly studied at any time for any initial atomic as well as field state.
COHERENT EVOLUTION AND TUNNELING CHARGE STEP IN A DRIVEN MESOSCOPIC JOSEPHSON JUNCTION
Authors: SHAO BIN , ZOU JIAN , LI QIANSHU
Published: July 2002

We consider a circular superconductor with a weak link mesoscopic Josephson junction in the presence of a dc voltage bias. Using the time-dependent perturbated method, we obtain the unitary evolution operator of the mesoscopic junction system and show that an initial vacuum state of the junction can evolve into a class of superposition of coherent states. Further, we show that the charge tunneling through the junction can exhibit step properties in the mesoscopic system.
CRITICAL BEHAVIOR OF A FOUR-STATE IRREVERSIBLE MODEL WITH POTTS SYMMETRY
Authors: BRUNSTEIN A. , TOMÉ T.
Published: July 2002

We analyze the critical behavior of a two-dimensional irreversible cellular automaton whose dynamic rules are invariant under the same symmetry operations as those of the three-state Potts model. We study the dynamical phase transitions that take place in the model and obtain the static and dynamical critical exponents through Monte Carlo simulations. Our results indicate that the present model is in the same universality class as the three-state Potts model.
QUANTUM JOSEPHSON RELATIONS FOR MACROSCOPIC JOSEPHSON SYSTEMS
Authors: CHEN ZENG-BING
Published: July 2002

The quantum version of the Feynman two-state model in describing the Josephson systems is shown to be equivalent to a quantum two-mode coupled oscillator. Such equivalence permits us to treat the Josephson systems in a fully quantum mechanical manner in the two-state model and to reveal secondary macroscopic quantum effects therein. The noncommuting nature of macroscopic variables is crucial in doing so. An interesting application of the present investigation into granular superconductor and high-temperature superconductor is briefly addressed.
THREE-DIMENSIONAL OBJECT RECOGNITION USING AN ORTHOGONAL COMPLEX AR MODEL APPROACH
Authors: TO F. W. , TSANG K. M.
Published: July 2002

The analysis and recognition of 2D shapes using the orthogonal complex AR model has been extended for the recognition of arbitrary 3D objects. A 3D object is placed at one of its stable orientation and sectioned into a fixed number of "slices" of equal thickness in such a way that the "slices" are parallel to the object's stable plane. The surface of an object can be represented by a sequence of these parallel 2D closed contours. A complex AR model is then fitted to each of these contours. An orthogonal estimator is implemented to determine the correct model order and to estimate the associated model parameters. The estimated AR model parameters, magnitude ratios and the relative centroid associated with each 2D contour are used as essential features for 3D object recognition. An algorithm with hierarchical structure for the recognition of 3D objects is derived based on matching the sequence of 2D contours. Simulation studies are included to show the effectiveness of different criteria being applied at different stages of the recognition process. Test results have shown that the proposed approach can provide a feasible and effective means for recognizing arbitrary 3D objects which can be self-occluded and have a number of stable orientation.
SENTENCE LIPREADING USING HIDDEN MARKOV MODEL WITH INTEGRATED GRAMMAR
Authors: YU KEREN , JIANG XIAOYI , BUNKE HORST
Published: July 2002

In this paper, we describe a systematic approach to the lipreading of whole sentences. A vocabulary of elementary words is considered. Based on the vocabulary, we define a grammar that generates a set of legal sentences. Our lipreading approach is based on a combination of the grammar with hidden Markov models (HMMs). Two different experiments were conducted. In the first experiment a set of e-mail commands is considered, while the set of sentences in the second experiment is given by all English integer numbers up to one million. Both experiments showed promising results, regarding the difficulty of the considered task.
AN EXPERIMENTAL STUDY OF NONLINEAR DYNAMICS AND CHAOS IN A NONAUTONOMOUS ELECTRONIC CIRCUIT
Authors: SEN ASOK K.
Published: July 2002

In this work we investigate experimentally the dynamics of a piecewise-linear nonautonomous electronic circuit proposed by Lacy [1996]. In particular, we examine the effect of a dc offset in the input signal. The circuit is first driven by a sine wave with a dc offset. When the amplitude and frequency of the sine wave are suitably chosen and the dc offset is varied, the output of the circuit is found to undergo a rich variety of bifurcations including chaos. A nonzero dc offset can also suppress a chaotic response which persists when the dc offset is zero. Furthermore, for certain amplitude and frequency of the sine wave input with no dc offset, an intermittent response is observed. The intermittent response may be altered by introducing a small amount of dc offset, resulting in a regular periodic motion or fully developed chaos. In addition, by varying the dc offset we have observed mode locking phenomena and a devil's staircase pattern. Finally the response of the circuit to a burst wave input is explored. We find that depending on the parameter values of the burst wave, the circuit may exhibit complex dynamics consisting of intermittency, chaos and mixed-mode oscillations.