bluuebunny/crossref_metadata_2025 huggingface dataset:
TRAPPED FLUX EFFECTS ON CRITICAL CURRENT OF POLYCRYSTALLINE YBa2Cu3Ox
Authors: WANG F.R. , WEN Q.Z. , Li C.Y. , DAI Y.D. , YIN D.L. , ZHOU M.L.
Published: November 2004

The transport critical current measurements were performed on polycrystalline YBa 2 Cu 3 O x in various thermal and magnetic field cyclings. The magnetic history and magnetic field dependence of Jc reveals that there are many strong links between grains in YBa 2 Cu 3 O x polycrystalline samples.
PHONON SPECTRUM AND THE ELASTIC CONSTANTS OF HIGH TcBa2YCu3O7
Authors: GUPTA H.C.
Published: November 2004

The phonon spectrum and the elastic constants of high superconducting transition temperature compound Ba2YCu3O7 have been investigated in both the tetragonal and the orthorhombic phases using an angular force model. The zone centre phonons agree well with the Raman and the infra-red measurements in the case of tetragonal phase as compared to the orthorhombic one. The acoustical phonons exhibit phonon anomalies in both the tetragonal and the orthorhombic structures. Number of optical phonons do not show dispersion in [ooq] direction indicating strong 2-dimensional features. The relevance of the phonons to the high temperature superconductivity is discussed. The elastic constants do not indicate anisotropy in either of the tetragonal or the orthorhombic phases.
ANOMALOUS BEHAVIOR IN HIGH-Tc SUPERCONDUCTORS BASED ON YBa2Cu3O7–y
Authors: RAJARAJAN A.K. , GUPTASARMA P. , PALKAR V.R. , AYYUB P. , GUPTA L.C. , VIJAYARAGHAVAN R. , MULTANI M.S.
Published: November 2004

We report our observation of some anomalous superconducting fluctuations in (RE) Ba 2 Cu 3 O 7−y and associated systems. The resistivity behavior of Y(Ba 1.6 K 0.4) Cu 3 O 7−y shows a transition from semiconducting to superconducting on thermal cycling. In a sample of Y(Ba 1.8 Pb 0.2) Cu 3 O 7−y, superconductivity was found to be extremely short-lived. A reproducible magnetic response was observed just above the onset of superconductivity in ( Y 0.9 Ca 0.1) Ba 2 Cu 3 O 7−y.
MICROWAVE ABSORPTION BY SINGLE CRYSTALS OF SUPERCONDUCTING Bi2(Ca,Sr)3Cu2O8+δ
Authors: MURTHY KUMARI , VARMA K.B.R. , BHAT S.V. , RAO C.N.R.
Published: November 2004

Microwave absorption (9.15 GHz) by single crystals of Bi 2 (Ca,Sr) 3 Cu 2 O 8+δ has been investigated. The absorption is anisotropic and the intensity goes to zero well above the superconducting transition.
VERY ANOMALOUS HYSTERESIS IN GRANULAR HIGH TEMPERATURE SUPERCONDUCTING CERAMICS
Authors: AUSLOOS M. , LAURENT Ch , PATAPIS S.K. , RULMONT A. , TARTE P.
Published: November 2004

The observation of a very anomalous hysteresis in the resistivity behavior of granular high temperature ceramic superconductors, under the influence of a low magnetic field, in the critical temperature region [TR, Tc] is discussed. After eliminating various a priori possible mechanisms, such as that of superconductive glass state, we present arguments strongly suggesting that the effect comes from flux pinning effects and the peculiar grain “boundary condition” effects.
MULTIPOLE EXPANSION APPROACH TO OSTWALD RIPENING
Authors: IMAEDA T. , KAWASAKI K.
Published: November 2004

A multipole expansion theory is used to derive a kinetic equation for a collection of droplets undergoing the Ostwald ripening or coarsening in two dimensions. The theory allows the morphological change of coarsening droplets as well as the migration behavior. Numerical computations are performed to give a good estimate to the solution of Laplace equation even in a few mode truncation.
THERMAL EXPANSION COEFFICIENTS OF YBa2Cu3O7−x WITH ORTHORHOMBIC AND TETRAGONAL PHASES
Authors: RUAN Y.Z. , LI L.P. , HU X.L. , PENG D.K. , HU J.B. , ZHANG Y.H.
Published: November 2004

Thermal expansion coefficients of YBa 2 Cu 3 O 7−x with the tetragonal and orthorhombic structural phases were measured by the method of differential parallel-plate capacitance. There exist anomalies near 205 K for orthorhombic phase and between 92–130K for tetragonal phase, respectively. We suggest that the former may be related to the lattice instability, indicating that there is a strong electron-phonon interaction; the latter may be result from the structural phase transition which damages the high T c superconductivity. In the meantime, a small jump of the thermal expansion coefficient at T c was observed in the orthorhombic phase and from this the pressure effect was estimated.
MAGNETIC PROPERTY AND CRITICAL CURRENT OF BiSrCaCuO SYSTEM UNDER LOW MAGNETIC FIELD
Authors: CAO L.Z. , YUE Y. , WANG J. , MAO S.D. , LIU H.B. , CAI W.L. , ZHANG Y.H.
Published: November 2004

The low critical field H c1 is determined by a.c.χ versus H and M versus H. For a sample of BiSrCaCuO with T c (0)=89 K , H c1 is equal to 17.5 Oe at 77 K. Measurement of the critical current Jc under low magnetic field shows that there is a peak on J c -H curve at about 1 Oe due to the existence of the earth’s magnetic field and the current density is very small in the BiSrCaCuO system and J c is nearly zero when the magnetic field reaches 150 Oe. It is suggested that the pinning force is very weak in this material.
DESCRIPTION OF THE Tl, Pb and Bi CUPRATE HIGH-Tc SUPERCONDUCTORS AS INTERCALATION COMPOUNDS
Authors: MARKIEWICZ R.S. , GIESSEN B.C.
Published: November 2004

Treating the new superconducting oxides as intercalation compounds, especially, as analogues to graphite intercalation compounds (GIC), clarifies the understanding of a number of their properties; in this description, the ratio of the number of cuprate layers per intercalant unit is equivalent to the stage number in GIC’s.

In particular, the role of charge transfer (presumably, electron transfer from oxygen in the [Formula: see text] sheets to an acceptor site located in the intercalant) in optimizing Tc can be well discussed in these terms, leading to the prediction that the curve of Tc versus n, the number of [Formula: see text] layers, must have a maximum at a specific value of n.
SUPPRESSION OF THE SUSCEPTIBILITY DIVERGENCE AT THE TRANSITION BETWEEN THE NÉEL AND THE RESONANTING VALENCE BOND PHASES OF THE HEISENBERG ANTIFERROMAGNET
Authors: SHAPIR YONATHAN
Published: November 2004

The antiferromagnetic susceptibility is at most weakly divergent at an assumed Néel to resonanting valence bond (RVB) phase transition. This result, derived from the mapping onto a classical O(4) model in the “quenched approximation”, is argued to hold under the most general circumstances due to the constraints on the RVB states. It may provide an experimental distinction between the transition to an RVB and to a paramagnetic phase.
HIGH TEMPERATURE SUPERCONDUCTIVITY IN COPPER AND BISMUTH BASED OXIDES
Authors: CAVA R.J.
Published: November 2004

In this letter, a brief comparison of copper and bismuth based high Tc superconductors is presented.
SEARCH FOR THE PROPOSED COLD FUSION OF D IN Pd
Authors: CHU C.W. , XUE Y.Y. , MENG R.L. , HOR P.H. , HUANG Z.J. , GAO L.
Published: November 2004

A direct, systematic, and well-controlled investigation of D2O-Pd electrolytic cells reveals neither neutrons at a rate exceeding 103 s −1 nor excess heat greater than 3% of the total input power generated during the electrolytic process in contrast to the cold fusion recently reported. No difference in the thermal energy outputs between two identical D2O-Pd and H2O-Pd cells greater than 1.5% (or 5%) of the input at 0.5 W (or 2.4 W) was detected. The negative results cannot be attributed to electrolysis-time (0–480 hours), Pd-electrode (cold drawn or cast) size (0.1–0.6 cm diameter × 3–5 cm), power input (0.1–8.5 W), electrolytes used (LiOH, LiCl, and DCl), or failure to deuterize Pd (PdDx with x≤0.6) within the limits cited in the parentheses. If the proposed cold fusion exists, it has to be induced only under some subtle and not-yet-determined conditions.
CALCULATED DIELECTRIC PARAMETERS OF BARIUM TITANATE-SODIUM NIOBATE COMPOSITES AS FUNCTION OF COMPOSITION AND FREQUENCY
Authors: SARKAR S.K.
Published: November 2004

Some dielectric parameters e.g. dielectric constant, resistivity, dielectric strength, loss tangent, coercive field and saturation polarization of barium titanate-sodium niobate composites have been calculated as a function of composition and frequency. assuming a very simplified model and a 3–0 connectivity pattern. Most of the parameters have been found to vary linearly with composition at a given frequency.
TRANSPORT CRITICAL CURRENT DENSITIES IN Y–Ag–Ba–Cu–O SUPERCONDUCTORS
Authors: MAJOROŠ M. , HANIC F. , POLÁK M. , KEDROVÁ M.
Published: November 2004

The influence of Ag substitution in amount of 2 mol% instead of Y, Ba and Cu in Y 1 Ba 2 Cu 3 O 7−x high temperature superconductor on magnetic field dependence of the critical current density at 77 K was studied. The samples were prepared by powder technology as well as by citrate method. An increase of transport critical current density as well as its smaller magnetic field dependence was found in case of substitution Ag → Y and Ag → Ba for samples prepared by both methods. In the magnetic field 9 T, the transport critical current density of the sample Y 0.98 Ag 0.02 Ba 2 Cu 3 O 7−x was 0.3 A/cm 2. On the other hand, substitution Ag → Cu lowers transport critical current densities in comparison with undoped samples. The effect of Ag substitution was more pronounced in samples prepared by powder technology.
ELECTRICAL CONDUCTIVITY OF POLY IRON ACRYLATE
Authors: KHWAJA FARID A. , IQBAL M. , RAZMI M. S. K. , CHOHAN M. H.
Published: November 2004

An investigation of the electrical conductivity of poly iron acrylate is carried out with particular reference to its temperature dependence. A number of interesting conclusions are drawn.
POTENTIAL OF A DEUTERIUM MOLECULE TRAPPED IN AN EXTERNAL FIELD OF SCREENED POINT CHARGES WITH fcc-SYMMETRY
Authors: LANGANKE KARLHEINZ
Published: November 2004

We have studied a simple model problem considering a deuterium molecule which is trapped within the field of screened point charges. The latter are assumed to be located on the surface of a cube having fcc symmetry. Within the Born-Oppenheimer approximation, we have calculated the potential between the two deuterons for this problem using a Path Integral Monte Carlo technique. We do not find significant deviations from the Born-Oppenheimer potential for a free deuterium molecule.
LOCAL MAGNETIC FIELDS IN THE Cu SITES OF YBa2Cu3−xFexOy DETECTED BY MÖSSBAUER SPECTROSCOPY
Authors: GOMEZ R. , ABURTO S. , MARQUINA V. , MARQUINA M. L. , QUINTANAR C. , JIMENEZ M. , BARRIO R. A. , ESCUDERO R. , RIOS-JARA D. , AKACHI T.
Published: November 2004

The temperature behavior of the observed asymmetries in the quadrupole doublets of the Mössbauer spectra of a superconducting YBa 2 Cu 3−x Fe x O y sample, for x = 0.125, suggests the existence of small local magnetic fields, superimposed to an electric field gradient in the positions of the iron atoms, which are assumed to be the Cu(1) sites of the structure. Some possible origins of those fields are discussed.
ENHANCEMENT OF NUCLEAR FUSION IN A STRONGLY COUPLED COLD PLASMA
Authors: LO S. Y.
Published: November 2004

It is pointed out that enhancement of nuclear fusion in a strongly coupled cold plasma can be realized in laboratory condition.
SELF-CONSISTENT X-RAY DIFFRACTION PATTERNS OF PERFECT CRYSTAL
Authors: CAMPOS H. S. , KELLER W. A.
Published: November 2004

We have developed a self-consistent X-ray scattering model for perfect crystal, which leads to obtain diffraction patterns similar to experimental findings. As an application of the model we carried out the calculations for the Si[333] reflection curve.
EVIDENCES FOR UNCONVENTIONAL SUPERCONDUCTIVITY IN RARE-EARTH INTERMETALLICS
Authors: SERENI J. G. , NIEVA G. L. , SCHMERBER G. , KAPPLER J. P.
Published: November 2004

The specific heat of CeRu 2 and La 5 Rh 4 of the superconducting state does not follow a BCS-exponential temperature dependence, but a T2 law. At very low temperature (T = 0.1 T c ), CeRu 2 shows a linear T dependence, which corresponds to a constant density of states. The experimental results are well described by the theoretical predictions for an axial state ( CeRu 2) and polar state ( La 5 Rh 4) superconductors. The small Sommerfeld coefficient of La 5 Rh 4(γ = 3.4 mJ/K 2 La at. ) excludes this compound from the heavy fermion superconductors.
ON THE INFLUENCE OF POSSIBLE MECHANISM OF INTERPLANE INTERACTION ON HIGH Tc
Authors: SOSNOWSKI J.
Published: November 2004

The possible influence of attractive interplane interaction on the critical temperature of high T c ceramics is considered. The influence of the number of interacting planes, what roughly may correspond to the yttrium based and bismuth ceramic samples is investigated. The results indicate that even for relatively weak interplane coupling constant high T c connected with this interaction may be reached for appropriate spectrum of excitations.
GROWTH AND MORPHOLOGY STUDIES OF BiSrCaCu2Oy CRYSTALS
Authors: SURESHKUMAR P. , SUBRAMANIAN C. , RAMASAMY P.
Published: November 2004

Thin single crystalline layers of BiSrCaCu 2 O y from molten solvent KCl and narrow blade-like crystals of the same compound from the solvent KI were grown using high temperature solution technique. They exhibited superconducting transition at 80 K. The grown crystals were scanned through optical and scanning electron microscopes and their growth mechanism was interpreted. X-ray diffractogram showed the structure as orthorhombic with a = 5.42 Å, b = 5.45 Å and c = 30.77 Å.
GAUGE THEORY OF ANTIFERROMAGNETISM IN TWO DIMENSIONS FOR LARGE RANK SYMMETRY GROUP
Authors: KHVESHCHENKO D. V. , WIEGMANN P. B.
Published: November 2004

We examine long wavelength fluctuations in two-dimensional magnetic systems with the symmetry group of a large rank N. The mean field solution is obtained and the existence of the parity-violating ground state is established. On the basis of the 1/N expansion, an effective gauge theory containing the Chern-Simons term is derived, which allows one to obtain a spectrum, spin and statistics of long wavelength excitations.
THEORY OF ELECTRON SOLVATION
Authors: SINGH YASHWANT
Published: November 2004

A theory for excess electrons in deformable media is reviewed. The nature of the electronic states and the phenomena of localization are discussed.
SQUEEZING AND OTHER NON-CLASSICAL FEATURES IN k-PHOTON ANHARMONIC OSCILLATOR IN BINOMIAL AND NEGATIVE BINOMIAL STATES OF THE FIELD
Authors: JOSHI AMITABH , LAWANDE SURESH V.
Published: November 2004

A systematic study of squeezing obtained from k-photon anharmonic oscillator (with interaction hamiltonian of the form (a†)kak, k ≥ 2) interacting with light whose statistics can be varied from sub-Poissonian to poissonian via binomial state of field and super-Poissonian to poissonian via negative binomial state of field is presented. We predict that for all values of k there is a tendency increase in squeezing with increased sub-Poissonian character of the field while the reverse is true with super-Poissonian field. We also present non-classical behavior of the first order coherence function explicitly for k = 2 case (i.e., for two-photon anharmonic oscillator model used for a Kerr-like medium) with variation in the statistics of the input light.
THE ANISOTROPIC RESISTIVITY OF Pb-DOPED Bi–Sr–Ca–Cu–O SINGLE CRYSTAL
Authors: ZHENG D. N. , YAN Y. F. , NI Y. M. , CHEN G. H. , YANG G. , YANG Q. S. , ZHAO Z. X.
Published: November 2004

The resistivity of superconducting Pb-doped Bi–Sr–Ca–Cu–O single crystal, with 2212 structure, has been measured using Montgomery technique. The resistivity, like in other high T c oxide superconductors, shows very strong anisotropic characteristic, with a typical metallic behavior but remains a residual resistivity at T = 0 K in the direction parallel to the a − b plane and a "semiconducting-like" temperature dependence in the c direction. The anisotropy (ρc/ρab) is about 104. But the value of resistivity in a − b plane is larger than that of Bi 2 Sr 2 CaCu 2 O y crystal. This may imply that the Bi–O plane plays an important role in superconductivity in this kind of structure.
THERMO-STIMULATED EXOEMISSION (TSEE) FROM GdBa2Cu3O7−x IN THE NORMAL STATE
Authors: GOŁEK F. , KLAMUT P. W. , SUJAK B. , ZALESKI A. J. , CISZEK M. , OLEJNICZAK J.
Published: November 2004

Measurements of electron beam excited TSEE from the high T c superconductor GdBa 2 Cu 3 O 7−x were performed in the temperature range from 80 to 350 K. To prove that the emission peaks originate from the sample, the sample was covered with a film of KC1. Exoemission peaks at 160 K and 240 K most probably ascribed to the sample. They might be connected with the first-order phase transition discovered recently in this temperature region by another method. If we assume the existence of localized electrons at oxygen vacancies and a simple mechanism for their delocalization, we can calculate an activation energy.
CALCULATED DIELECTRIC PARAMETERS OF BARIUM TITANATE-LEAD ZIRCONATE COMPOSITES AS A FUNCTION OF COMPOSITION AND FREQUENCY
Authors: SARKAR S. K.
Published: November 2004

Some dielectric parameters e.g. dielectric constant, resistivity, dielectric strength, saturation polarization, loss tangent and coercive field of barium titanate-lead zirconate composites have been calculated as a function of composition and frequency. Most of the dielectric parameters have been found to vary linearly with composition and frequency. A 3–0 connectivity pattern of the composites has been assumed in calculating the dielectric parameters.
THE SPIN-LATTICE INTERACTION AND THE LATTICE STATICS AND DYNAMICS IN THE COPPER OXIDES WITH NON-COLLINEAR Cu–O–Cu BONDS
Authors: LOOS J.
Published: November 2004

The relevance of the superexchange energy for the lattice statics and dynamics of the superconducting copper oxides is estimated. It is shown that the dependence of the exchange constant on the oxygen ion position in the non-collinear Cu–O–Cu bond can produce non-negligible effects, especially in lanthanum copper oxides.
CHANGE OF ELECTRON-PHONON COUPLING COMPANYING SUPERCONDUCTIVITY-TRANSITION IN Cu–O SYSTEM
Authors: XIA SHANGDA , HOU BIHUI
Published: November 2004

The strong zero-field microwave absorption in ESR spectra was observed at certain energy from 3 × 10−4 cm −1 to 0.3 cm −1 in various high-T c superconductors of Cu–O compounds when T < T c . Especially, S. V. Baht et al.1 found that this absorption is much stronger for sample in air than that contained in vacuum-tube, he suggested that the absorption was oxygen-induced. Furthermore, the observed absorption is stronger for pieces-sample smashed than for bulk-sample.
PROPERTIES OF ELECTRON-DOPED SUPERCONDUCTORS
Authors: UCHIDA S.
Published: November 2004

In previously known high-T c copper oxide superconductors the charge carriers have been electron vacancies or holes. By contrast, we have recently discovered a class of superconducting copper oxides with the formula Ln 2−x Ce x CuO 4 in which the doped carriers are electrons. We described here how we created the new superconductors and discuss their physical properties.
A NOTE ON THE MODE COUPLING THEORY OF POLYMER MELT DYNAMICS
Authors: KAWASAKI KYOZI
Published: November 2004

The mode coupling theory of polymer melt dynamics put forward recently by Schweizer is combined with the curvilinear displacement invariance of the potential energy. The resulting equation of motion of a tagged polymer chain is shown to be consistent with the reptation picture when the matrix surrounding the tagged chain is frozen.
TEMPERATURE AND HYDROSTATIC PRESSURE DEPENDENCE OF SUBBAND STRUCTURE IN GaAs/AlxGa1−xAs MULTIPLE QUANTUM WELL
Authors: FU Y.
Published: November 2004

The temperature and hydrostatic pressure dependence of GaAs/AlxGa1−xAs multiple quantum well subband structures has been examined theoretically. Such effects on the subband energy measured from the corresponding band optimum are negligible, and therefore, the temperature and the hydrostatic pressure coefficients of these multiple quantum wells are dominated by those coefficients of the bulk GaAs bandgap.
NON-LOCAL TERMS IN THE ELASTIC FREE ENERGY OF DISTORTED NEMATICS
Authors: BARBERO G.
Published: November 2004

The presence of second order derivatives of the tensorial order parameter characterizing the nematic phase in the elastic free energy density of distorted nematics is considered. By using a Landau- de Gennes expansion it is shown that if a linear term in second order derivative is considered, it is also necessary to take into account the quadratic term in the same derivative. In fact, this gives a contribution of the same order of the linear term, if the scalar order parameter is used as expansion parameter. The analysis presented here is valid not only for the second order derivatives, but in general. The temperature dependence of the elastic constants connected to linear terms is discussed by considering a simple molecular model.
THE MEISSNER EFFECT AND INFINITE CONDUCTIVITY IN ANYON SUPERCONDUCTOR AT FINITE TEMPERATURE
Authors: KAO Y.C. , YANG M.F.
Published: November 2004

We study the conductivity tensor for the pure anyon system at finite temperature by calculating the electromagnetic response function Kμν(ω, k) in the random-phase approximation. We find that the conductivity is indeed infinite through the vanishing of the renormalized Chern-Simons term for the statistical gauge fields in the limit k=0, ω→0. To study the Meissner effect at finite temperature, others have looked at Kµν(ω, k) in the limit ω=0, k→0. We compare the results and make some comments.
CATION ANTISITE DEFECTS AND ANTISITE-BASED-DEFECT COMPLEXES IN GaAs
Authors: ZHANG S.B.
Published: November 2004

Recent theory predicted that the Ga and B antisites in GaAs are bistable. As the Fermi level is lowered towards the valence-band maximum, a structural change from fourfold to threefold coordination will occur. The Ga antisite will undergo an atomic exchange in the presence of an As interstitial.
SURFACE ROUGHENING IN A CLASS OF GROWTH MODELS
Authors: FORREST BRUCE M. , TANG LEI-HAN
Published: November 2004

A brief review of some recent results on a particular class of growth models is presented. Numerical estimates for the roughness exponents of a d-dimensional surface are discussed, as is the question of the existence of a non-equilibrium roughening transition for the experimentally relevant and theoretically controversial case of d=2.
INFLUENCE OF DEFECTS ON THE CRITICAL FIELD OF THE SUPERCONDUCTING NUCLEATION
Authors: SIMONOV A. YU. , MELNIKOV A.S. , SHAROV S.V.
Published: November 2004

It is shown that the existence of planar defects near the surface of a superconductor or crystal edges lead to an increase of the surface superconductivity nucleation field as compared with its usual Hc3=1.695Hc2 value.
NEGATIVE DIFFERENTIAL CONDUCTANCE BY FIELD-INDUCED LOCALIZATION AND SCATTERING-CONTROLLED RESONANCES IN SUPERLATTICES
Authors: BELTRAM FABIO , CAPASSO FEDERICO , SIVCO DEBORAH L. , CHO ALFRED Y.
Published: November 2004

Recent results on the physics of transport in semiconductor superlattices (SLs) are reviewed. It is shown that two mechanisms of negative differential conductance in SLs (Bragg diffraction and field induced localization), previously viewed as different, are actually physically equivalent. Moreover the physics of newly observed scattering-controlled resonances is presented.
QUENCHED RANDOMNESS IN UNCONVENTIONAL SUPERCONDUCTORS
Authors: MILLEV Y.T.
Published: November 2004

The renormalisation-group analysis is used to study the influence of quenched disorder of the random-Tc type upon the critical properties of unconventional superconductors to first order in ε. Several new fixed points of the flow equations are located. The analysis of their stability shows that quenched randomness in models of unconventional superconductors does not change the first-order character of the transition which has been found to be the rule in pure unconventional superconductors.
CROSSOVER FROM SEMIDILUTE TO CONCENTRATED POLYMER SOLUTIONS: FINITE VOLUME FRACTION EFFECTS
Authors: SHIWA YASUHIRO , OONO YOSHITSUGU , BALDWIN PHILIP R.
Published: November 2004

Effects of a finite volume fraction of polymer on the osmotic pressure of moderately concentrated polymer solutions are investigated. The predicted deviation from the universal behavior as the monomer concentration increases closely accounts for the experimental result.
A PARALLEL NONLINEAR MAPPING ALGORITHM
Authors: SHEN C. W. , LEE R. C. T. , CHIN Y. H.
Published: November 2004

In this paper, we shall present a parallel algorithm to perform nonlinear mapping which is useful for clustering analysis and pattern recognition. This parallel nonlinear mapping algorithm is slightly different from the original nonlinear mapping algorithm. Experimental results show that our parallel nonlinear mapping algorithm works quite well.
EXPERT SYSTEMS FOR THERMAL AND STRUCTURAL ANALYSIS IN ELECTRONIC SYSTEM DESIGN
Authors: LIU HSI-HO , LAI YING-NAN , CORTOPASSI PEDRO
Published: November 2004

This paper presents an application of rule-based expert systems to thermal and structural analysis, part of mechanical engineering design, in electronic system design. The purpose of these expert systems is to serve as a consultant or design reviewer. These design expert systems are capable of performing both symbolic reasoning and numeric computation. The advantages of expert systems over conventional systems such as user friendliness, explanation and help facilities, and easy development and maintenance are also shown in this paper. Using system-subsystem tree structure several interrelated expert systems can be integrated into one system, and it is flexible for future expansion or modification. Object-oriented approach is also discussed, which with its unique representation of object could be a useful tool for engineering design.
PATTERN ANALYSIS FOR THE ULTRASONIC NONDESTRUCTIVE EVALUATION OF MATERIALS
Authors: CHEN C. H.
Published: November 2004

In this paper the use of digital pattern recognition in ultrasonic nondestructive evaluation (NDE) of materials is examined. Emphasis is placed on identifying effective features from time and frequency domains, correlation functions and impulse responses to classify aluminium plate specimen into three major defect geometries: flat and angular cuts, and circular holes. A multi-stage classification procedure is developed which can further determine the angles and sizes for defect characterization and classification. The research clearly demonstrates that modern pattern analysis can significantly improve the nondestructive material evaluation capability of the ultrasonic methods.
ANALYSIS OF SOUND PATTERNS THROUGH WAVELET TRANSFORMS
Authors: KRONLAND-MARTINET R. , MORLET J. , GROSSMANN A.
Published: November 2004

This paper starts with a brief discussion of so-called wavelet transforms, i.e., decompositions of arbitrary signals into localized contributions labelled by a scale parameter. The main features of the method are first illustrated through simple mathematical examples. Then we present the first applications of the method to the recognition and visualisation of characteristic features of speech and of musical sounds.
A PROLOG-BASED CHINESE EXPERT SYSTEM
Authors: SOO HSU LOKE
Published: November 2004

This paper presents the design and implementation of a Chinese Expert System Shell which is based on a Chinese Prolog interpreter.

The system is divided into three parts: the knowledge acquisition module, the knowledge application module and the inference engine.

The knowledge engineer defines the syntax of the language to be used by himself and by the users when they interact with the system. The natural language interface is table driven and can be modified easily.

The system also caters for the case when the domain expert finds it difficult to articulate the rules, but is able to give examples. An inductive engine is included to extract rules from examples.
A WORD-BASED CHINESE LANGUAGE UNDERSTANDING SYSTEM
Authors: YAO TIAN-SHUN
Published: November 2004

With the word-based theory of natural language processing, a word-based Chinese language understanding system has been developed. In the light of psychological language analysis and the features of the Chinese language, this theory of natural language processing is presented with the description of the computer programs based on it.

The heart of the system is to define a Total Information Dictionary and the World Knowledge Source used in the system. The purpose of this research is to develop a system which can understand not only Chinese sentences but also the whole text.
STROKE RELATION CODING—A NEW APPROACH TO THE RECOGNITION OF MULTI-FONT PRINTED CHINESE CHARACTERS
Authors: CHEN PO-NING , CHEN YUNG-SHENG , HSU WEN-HSING
Published: November 2004

This paper describes a new approach to the recognition of multi-font printed Chinese characters. The basic idea is to encode a character in terms of two pre-defined stroke relations, namely, relative position relation and relative direction relation. The code-mapping method chosen in our system possesses two main advantages: the first is that the tree-like data base can be easily extended, and the second is that the processing time is independent of the amount of data base. Since the stability of the extracted strokes greatly affects the coding results, a new stroke merging method, which has been experimentally proven to extract strokes more steadily, is also proposed.
ARRAY ARCHITECTURES FOR ICONIC AND SYMBOLIC IMAGE PROCESSING
Authors: FOUNTAIN T.J.
Published: November 2004

Three architectures of current interest—the pyramid, the linear array and the n-cube—are examined in relation to their ability to perform iconic and symbolic image processing. For each architecture an appropriate problem is identified and a matching implementation selected. An assessment of the characteristics of each implementation is given, together with an estimation of the performance on a number of fundamental operations. The relative merits of the designs are discussed but it is concluded that the success of a particular architecture depends crucially upon the type of application which is addressed, and that therefore no universally applicable ranking can be derived in the absence of a comprehensive benchmarking exercise.
GSS—A FAST, MODEL-BASED VISION SYSTEM FOR WORKPIECE RECOGNITION
Authors: RUMMEL PETER , KÖLLENSPERGER PAUL
Published: November 2004

This paper describes a new visual sensor system for the recognition of touching and overlapping workpieces, designed to meet the requirements of real applications in the factory. The system analyses the grey scale image and comprises two stages: a feature-extraction stage, which is designed mainly in special-purpose hardware, and a model-based analysis stage. The system works with edge-based geometrical primitives and surface features. The model comprises topographical and procedural information in order to control the image-analysis, which is based on the “heuristic-search” technique. The hardware and software design is modular. The system is working well in a wide range of environmental conditions and with different kinds of workpieces. A prototype version is completed and has proved its reliability and performance in several applications in the factory.
AN APPROACH FOR RECOGNIZING AND LOCATING OVERLAPPING INDUSTRIAL PARTS
Authors: BOUYAKHF E. H.
Published: November 2004

A new method recognizing and locating partially occluded two-dimensional parts is presented. The objects are described by a set of segments derived form the polygonal coding of their contours, and by the geometrical relationships between the segments. Rewriting rules are used to improve the stability of the polygonal coding. The identification process utilizes a robust hypothesis generator, from which the segment research assisted by the spatial relationship is propagated into the scene. The originality of this method relies mainly on the use of structural relationships between the segments to select the robust initialization hypotheses, and the use of structural research to achieve hypothesis propagation. These last two points with the use of a hash-coding technique to improve the location of predicted segments, greatly reduce the combinatories and make the algorithm particularly rapid and effective. This approach is integrated within a vision system of a Flexible Assembly Workcell to accomplish the automatic assembly of partially overlapping parts.
DIAGNOSTIC MECHANISM MODELING
Authors: FARLEY ARTHUR M.
Published: November 2004

Diagnostic models of complex mechanisms are designed specifically to support diagnostic reasoning. Diagnostic reasoning is that aspect of troubleshooting which determines a set of component faults that can account for observed abnormalities in system performance. A system’s performance is evaluated by comparing observations of the system’s behavior with its functional specifications. As such, diagnostic models must incorporate elements of both function as well as behavior. We define two necessary properties of diagnostic models reflecting this outlook: architectural fidelity and functional adequacy. We then discuss two general principles of diagnostic modeling, based upon observations from expert protocols: model variables assume values relative to normal levels (the normality principle) and these values are propagated through the model to account for the production of single outputs (the single output principle). These two principles allow significant simplification in the definition of diagnostic models of complex mechanisms. We illustrate our approach to diagnostic modeling and reasoning with examples from xerography.
SIROMONEY ARRAY GRAMMARS AND APPLICATIONS
Authors: SUBRAMANIAN K. G. , REVATHI L. , SIROMONEY R.
Published: November 2004

The Siromoney matrix model is a simple and elegant model for describing two-dimensional digital picture languages. The notion of attaching indices to nonterminals in a generative grammar, introduced and investigated by Aho. is considered in the vertical phase of a Siromoney matrix grammar (SMG). The advantage of this study is that the new model retains the simplicity and elegance of SMG but increases the generative power and enables us to describe pictures not generable by SMG. Besides certain closure properties and hierarchy results. applications of these two-dimensional grammars to describe tilings, polyominoes, distorted patterns and parquet deformations are studied.
USE OF MULTILAYER PERCEPTRON FOR RECOGNITION OF EVOKED POTENTIALS
Authors: BRUHA I. , MADHAVAN G.P. , CHONG M.S.-K.
Published: November 2004

A recognition system consisting of attributed grammars and a two-layer perceptron for classifying brain-stem auditory evoked potentials is described. An evoked potential waveform is filtered and converted to a string of terminal symbols. This string is then processed by a regular attributed grammar. Its semantic functions return a list of numeric features that are further processed by a two-layer perceptron. The paper discusses the results of a large number of experiments that have been conducted to obtain the performance characteristics of a multilayer perceptron on a specified pattern recognition problem.
On the edge set of graphs of lattice paths
Authors: Klee Steven , Pudwell Lara , Gillman Rick
Published: November 2004

This note explores a new family of graphs defined on the set of paths of the m × n lattice. We let each of the paths of the lattice be represented by a vertex, and connect two vertices by an edge if the corresponding paths share more than k
steps, where k
is a fixed parameter 0 = k = m + n. Each such graph is denoted by G(m, n, k). Two large complete subgraphs of G(m, n, k)
are described for all values of m, n, and k. The size of the edge set is determined for n = 2, and a complicated recursive formula is given for the size of the edge set when k = 1.
On local smooth solutions for the Vlasov equation with the potential ofinteractions ±r−2
Authors: Zhidkov Peter
Published: November 2004

For the initial value problem for the Vlasov equation with the potential of interactions ±r−2, we prove the existence and uniqueness of a local solution with values in the Schwartz space S of infinitely differentiable functions rapidly decaying at infinity.
On the critical periods of Liénard systems with cubic restoring forces
Authors: Du Zhengdong
Published: November 2004

We study local bifurcations of critical periods in the neighborhood of a nondegenerate center of a Liénard system of the form , , where F(x)
and
g(x)
are polynomials such that deg(g(x)) ≤ 3, g(0) = 0, and g′(0) = 1, F(0) = F′(0) = 0
and the system always has a center at (0, 0). The set of coefficients of F(x)
and g(x) is split into two strata denoted by SI and SII and (0, 0) is called weak center of type I and type II, respectively. By using a similar method implemented in
previous works which is based on the analysis of the coefficients of the Taylor series of the period function, we
show that for a weak center of type I, at most [(1/2)deg(F(x))] − 1 local critical periods can bifurcate and the maximum number can be reached. For a weak center of type II, the maximum number of local critical periods that can bifurcate is at least [(1/4)deg(F(x))].
On some classes of almost periodic functions in abstract spaces
Authors: Bugajewski Dariusz , N′Guérékata Gaston M.
Published: November 2004

We deal with C(n)‐almost periodic functions taking values in a Banach space. We give several properties of such functions, in particular, we investigate their behavior in view of differentiation as well as integration. The superposition operator acting in the space of such functions is also under consideration. Some applications to ordinary as well as partial differential equations are presented. Moreover, we introduce the class of the so‐called asymptotically C(n)‐almost periodic functions and give some of their properties.
SIMULATION OF SYSTOLIC TREE AUTOMATA ON TRELLIS AUTOMATA
Authors: FACHINI EMANUELA , GRUSKA JOZEF , SCHETTINI ANDREA MAGGIOLO , SANGIORGI DAVIDE
Published: November 2004

The relation between two basic types of systolic automata—tree automata and trellis automata—is investigated. First it is shown that for every natural t>1 there is a simple nonhomogeneous (actually regular and also modular) trellis [Formula: see text] such that any t-ary systolic tree automaton can be simulated in a universal and quite straighforward way on a trellis automaton over [Formula: see text]. This implies that the family of languages accepted by systolic tree automata, which is incomparable with the family of languages accepted by homogeneous systolic trellis automata, is actually contained in the family of languages accepted by trellis automata that are both regular and modular.
THE DEVELOPMENT OF FORMAL LANGUAGE THEORY SINCE 1956
Authors: McNAUGHTON ROBERT
Published: November 2004

This brief survey will discuss the early years of the theory of formal languages through about 1970, treating only the most fundamental of the concepts. The paper will conclude with a brief discussion of a small number of topics, the choice reflecting only the personal interest of the author.
DYNAMIC OPTIMAL BINARY SEARCH TREE
Authors: KORAH A. P. , KAIMAL M. R.
Published: November 2004

In this paper we present a strategy to maintain a dynamic optimal binary search tree. The algorithms for insertion and deletion use swapping as the basic operation. Since in average situations the tree reorganization is limited to local changes, it can be favourably compared with the local balancing algorithms. The present algorithms dynamically maintain the optimal tree with an amortized time of O(log2 n), where n is the total number of nodes in the tree. In the worst case situations, the algorithms take only O(n) time. This is significant when they are compared to the algorithms producing static optimal binary search trees.
A NEURAL NETWORK MODEL TO SIMULATE A CONDITIONING EXPERIMENT
Authors: Patarnello Stefano , Carnevali Paolo
Published: November 2004

The most prominent area where the potential of neural networks is under study is that of engineering applications, such as pattern recognition and speech processing. Another interesting direction which is proposed in the present paper is that of neural networks designed to simulate the interaction of an individual with the external (varying) environment. The simple example presented here consists of a kind of conditioning experiment: a synthetic "organism" (provided with some "sensor" and "motor" neurons which are connected via a neural network) is free to move in a world where it has to find the food for its survival, and is naturally rewarded on the basis of the amount of food it is able to find. The whole training scheme results therefore in a sort of population selection, which finally produces skilled individuals (or networks) able to elaborate relatively subtle search strategies. It is remarkable that the learning scheme produces a differentiation of the task which each neuron performs: some of them behave as "clocks" which resonate at given frequencies (regardless of the external world), while some others are responsible for the interaction with the environment and detect the presence of food.
ADDING LEARNED EXPECTATION INTO THE LEARNING PROCEDURE OF SELF-ORGANIZING MAPS
Authors: Xu Lei
Published: November 2004

The self-organizing topological map is generalized by adding a learned expectation to its learning procedure, in order to improve its stability in nonstationary environments with unexpected inputs and abnormal noise. Such a learned expectation is realized through a compatibility test which checks whether an input is compatible with the earlier learned patterns on a map unit before the unit starts to adapt to the input. The generalized map consists of multi-maps with a pipeline architecture, equipped with a parallel search strategy which allows for the implementation of the learned expectation to be fulfilled without extra computing costs. Computer experiments on several examples are given to show the characteristics of the generalized map in comparison with the original map.
BISTABILITY OF DENDRITES
Authors: Gutman Aron M.
Published: November 2004

The theory of the ohmic electric function of dendrites is doubtful. A hypothesis was put forward that non-, partly or slow-accommodating neurons possess a slow inward dendritic current. It was predicted that these dendrites might be bistable, i.e., they might have stable depolarization in addition to the rest potential. Later, the prediction was confirmed experimentally: a steady inward current was observed when the motoneuron was clamped at the rest potential after strong depolarization. This current passes from dendrites to the soma because the distal dendritic membrane is under stable depolarization. The modeling of a neuron with bistable dendrites shows a hysteresis of the steady input current–voltage function and a hysteresis and jumps in the firing frequency–stimulating current relation. The theory of bistable dendrites explains a number of electrophysiological phenomena, and ascribes functional complexity to dendrites. Some experimental problems and neurocybernetical applications are suggested.
PREDICTING GANGLION AND SIMPLE CELL RECEPTIVE FIELD ORGANIZATIONS
Authors: Atick Joseph J. , Redlich A. Norman
Published: November 2004

Barlow's redundancy reduction hypothesis is applied using techniques developed from signal processing theory to derive the one-dimensional ganglion and simple cell kernels. The resulting closed-form expression for the ganglion cell kernel reduces redundancy over the entire range of signal-to-noise ratios, and resembles the phenomenological kernel. Significantly, it exhibits observed nontrivial dependence of the cell's parameters on background luminosity. The one-dimensional simple cell kernel is deduced by requiring that it maintain the redundancy reduction achieved by the ganglion cells despite the presence of intrinsic noise introduced through transmission along the optic nerve Neural update algorithms which converge to these cell profiles, starting from any initial set of synaptic strengths, are also derived. These learning algorithms turn out to be anti-Hebbian.
ADVANCES IN OPTOELECTRONIC INTEGRATION
Authors: WADA OSAMU
Published: November 2004

Optoelectronic integration, in which optoelectronic devices such as lasers and photodiodes are integrated with different optoelectronic and/or electronic devices together, is expected to be a key technology in developing future lightwave systems. This is because of its potential advantages in realizing high-performance, high-manufacturability and high-functionality in optoelectronic components, which have not been developed fully due to the limit of using conventional discrete devices and assembly technique. Optoelectronic integrated transmitters and receivers are currently being developed for lightwave telecommunication and interconnection applications by a number of researchers and recent progresses in both the performance and the fabrication technology are encouraging. For example, LSI level integration has been demonstrated in GaAs-based receivers and 5- to 10-Gb/s rate operations have been shown for InP-based integrated lasers. Also a variety of optical processing functions can be implemented by optoelectronic integration. Optical logic elements based on integrated lasers and also waveguide-based circuits for wavelength-multiplexing and optical heterodyne detection are such examples. Technological challenges in optoelectronic integration will lead to a generation of future advanced optical systems for not only communication but also switching and computing. This paper describes the recent progress of this technology and discusses future directions.
PROPAGATION DELAY IN HIGH SPEED SILICON BIPOLAR AND GaAs HBT DIGITAL CIRCUITS
Authors: TIEN P.K.
Published: November 2004

The needs for multi-gigabits/second digital electronics in advanced lightwave systems have motivated R & D for the next generation of high speed bipolar technology. The speed of the digital circuit may be estimated from the propagation delay of the logic gate. We discuss physics of the delay and show that it is fundamentally limited by the time needed for turning on (off) a transistor and by the time for charging (discharging) of capacitances in the circuit. We present a large-signal theory based on a charge-control model for the calculation of these limits. The results obtained for emitter coupled logic and current mode logic are used to analyze current technologies of silicon bipolar and GaAs HBTs.
EFFECTS OF A FUNDAMENTAL LATTICE ON THE THERMODYNAMICAL PROPERTIES OF A FREE BOSON GAS
Authors: AMUNDSEN PER A. , SKAGERSTAM BO-STURE K.
Published: November 2004

We point out that, if space has a fundamental lattice structure, there will be a temperature range where the energy density of a free boson (photon, gluon) gas is notably enhanced compared to what is predicted from Stefan-Boltzmanns law.
MULTIPLICITY DISTRIBUTION FOR DIFFERENT PSEUDORAPIDITY INTERVALS—FLUCTUATIONS AT FINITE ENERGIES
Authors: LI T S. , YOUNG K
Published: November 2004

The number n of charged particles in a rapidity window is determined by its average value N for a given total number of particles N, and by the fluctuation of n about N. Even at collider energies, the latter is not negligible for small windows. A simple model of the fluctuations is formulated in which particles are emitted in clusters of k charged particles with a pseudorapidity spread Δη. The model agrees well with the data if k≃2 and 0.5≳Δη≳0.2.
SOLITON EQUATIONS AND FREE FERMIONS ON RIEMANN SURFACES
Authors: ISHIBASHI NOBUYUKI , MATSUO YUTAKA , OOGURI HIROSI
Published: November 2004

Operator formalism for free fermions on general Riemann surfaces is developed based on the Sato theory of the Kadomtsev-Petviashvilli hierarchy. Moduli spaces of various genuses are included in Sato’s universal Grassmannian manifold (UGM), and we have investigated explicitly behaviour of this inclusion mapping near boundaries of moduli spaces.
$s-\bar{s}$ SEPARATION DURING HADRONIZATION OF A QUARK-GLUON PLASMA
Authors: HEINZ U. , LEE K.S. , RHOADES-BROWN M.J.
Published: November 2004

We present the equilibrium phase diagram for hadronic and quark matter containing strange particles and show quantitatively that at finite baryon density hadronization of quark-gluon plasma proceeds through a mixed phase in which [Formula: see text]-quarks hadronize first (as K+ and K0 mesons) and s-quarks get enriched in the plasma subphase.