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Showing papers by "Shanghai Jiao Tong University published in 1989"


Journal ArticleDOI
01 Mar 1989
TL;DR: The author proposes an approach to represent assembly by Petri nets and presents an algorithm of automatic robot assembly planning based on the Petri-net model, which is quite straightforward and can be easily and efficiently implemented with simple matrix manipulation.
Abstract: The author proposes an approach to represent assembly by Petri nets and presents an algorithm of automatic robot assembly planning based on the Petri-net model. The Petri-net model of assembly is configured by the goal structures and initial constraints, both in the Petri-net formalism. Due to the Petri-net representation of assembly, the plan generation is quite straightforward and the planning algorithm can be easily and efficiently implemented with simple matrix manipulation. An example of how to plan an assembly by the Petri net model is presented. >

67 citations


Journal ArticleDOI
TL;DR: The single unit power spectrum is investigated and the effects of firing rate mean and variance changes evaluated and results show that spectrum peaks will shift with firing rate and the median frequency is weakly dependent on firing rate.
Abstract: Changes in the power density spectrum of myoelectric signal with contraction level have been reported in the literature. These changes can be induced by a number of possible factors including recruitment of differing types of units, conduction velocity changes and firing rate changes. In the paper the single unit power spectrum is investigated and the effects of firing rate mean and variance changes evaluated. Motor unit signal simulation and experiments are carried out to verify predictions. The results show that spectrum peaks will shift with firing rate and the median frequency is weakly dependent on firing rate.

52 citations


Journal ArticleDOI
TL;DR: In this article, the formation of dislocation walls of persistent slip bands (PSBs) in cyclicly deformed copper crystals oriented for single slip has been investigated, and both macroscopic data, the stress-strain responses, the change of the shape of hysteresis loops and the nucleation stresses for PSB formation are presented.

50 citations


Journal ArticleDOI
TL;DR: In this paper, transmission electron microscopy studies were undertaken to characterize the formation, the imperfection, and the interfacial structure of grain boundary M23C6 carbide in a Ni-base superalloy.

41 citations


Journal ArticleDOI
TL;DR: This epoxy resin copolymer with zero shrinkage has been used as an adhesive to join the optical parts of a large optical telescope.
Abstract: Epoxy resin copolymer with zero shrinkage can be obtained by copolymerizing epoxy resin E51 with the expanding monomer of 3,9-di(5-norbornene-2,2)-1,5,7,11 -tetraoxaspiro[5,5]undecane (NSOC). The volume changes of an epoxy resin copolymerized with various amounts of NSOC during cure was measured with a dilatometer. The epoxy copolymer giving zero shrinkage was an epoxy resin with a E51:NSOC ratio equivalent to 5.88∶1. This epoxy resin copolymer with zero shrinkage has been used as an adhesive to join the optical parts of a large optical telescope.

29 citations


Journal ArticleDOI
TL;DR: In this article, the buckling load of a filamentary laminated circular cylindrical shell subjected to axial compression and/or external pressure was optimized using a two-step approach.

20 citations


Journal ArticleDOI
TL;DR: Internal fields in fused couplers have been investigated for the first time by measuring the near field and far field patterns at different cross sections of the coupler.
Abstract: Internal fields in fused couplers have been investigated for the first time by measuring the near field and far field patterns at different cross sections of the couplers. Detailed information concerning the internal fields in the couplers provides experimental evidence for the validity of the hybrid mode theory of fused couplers.

18 citations


Journal ArticleDOI
TL;DR: In this paper, the postbuckling behavior of perfect and imperfect rectangular plates under biaxial compression combined with lateral pressure is considered, based on the nonlinear large deflection equations of von Karman plates.
Abstract: Postbuckling behaviour of perfect and imperfect rectangular plates under biaxial compression combined with lateral pressure is considered. Based on the nonlinear large deflection equations of von Karman plates, the lateral pressure is first converted into an initial deflection by the Galerkin method. The postbuckling behaviour of simply-supported rectangular plates under biaxial compression combined with lateral pressure is then studied using a perturbation technique, taking deflection as its perturbation parameter. Through comparison, it is found that a discrepancy exists between the two cases; with and without lateral pressure. In the case of rectangular plates under uniaxial compression combined with lateral pressure, it is seen that the results obtained from the present paper are quite in accord with other experiments.

18 citations


Journal ArticleDOI
TL;DR: In this paper, it was shown that a planar homoclinic loop of a nongeneric cubic Hamiltonian has cyclicity two under arbitrary quadratic perturbations.
Abstract: New conditions for a planar homoclinic loop to have cyclicity two under multiple parameter perturbations have been obtained. As an application it is proved that a homoclinic loop of a nongeneric cubic Hamiltonian has cyclicity two under arbitrary quadratic perturbations.

17 citations


Journal Article
TL;DR: Several important intelligent control systems, including hierarchical intelligent control system and expert control system, have been overviewed and their structures have been discussed.
Abstract: The development of intelligent control and the structures and features of intelligent control systems have been introduced first in this paper.Several important intelligent control systems,including hierarchical intelligent control system and expert control system,have been overviewed.Their structures have been es- pecially discussed.

16 citations


Journal ArticleDOI
TL;DR: This paper attempts to propose a method for preference degree analysis in multiobjective decisionmaking problems (MDMPs), called the multiple factor analysis method based on a hierarchical analysis model.

Journal ArticleDOI
TL;DR: This paper deals with the development of a strategy of problem solving in a fuzzy reasoning network and the propositions involved are temporal knowledge representation with hierarchical structure with fuzzy sense, and forward and backward fuzzy reasoning.


Journal ArticleDOI
TL;DR: In this article, the authors used the Auger electron spectroscopy profiling technique to study the interdiffusion behavior and the effectiveness of the chromium and nickel layers as diffusion barriers.

Journal ArticleDOI
TL;DR: Experiments on using objective functions for synthetic and real images of translating and rotating objects generated velocity fields that are meaningful and consistent with visual perception.

Journal ArticleDOI
TL;DR: In this paper, the authors derived a general formula for ΔGβ→α, which is used to calculate the α (α + β′) and β′ (α+ β+) phase boundaries of the CuZn system.

Journal ArticleDOI
01 Nov 1989
TL;DR: In this article, a hysteresis model for simulating permanent magnets with knee points is presented, and the field solution for both a single magnet and a magnet assembly, each air-stabilised, are computed by the presented method.
Abstract: Since the demagnetisation curves of permanent magnets with knee points are not single-valued, hysteresis effects below the knee points need to be considered. A field problem with an unknown and nonuniform permanent-magnet source distribution occurs. A hysteresis model for simulating permanent magnets with such knee points is presented in the paper. By using the model and a permanent-magnet source-iteration method, the field problem can be easily solved by the finite-element method. The field solutions for both a single magnet and a magnet assembly, each air-stabilised, are computed by the presented method, and are found to be in good agreement with test results.

Journal ArticleDOI
TL;DR: In this paper, the copolymerization of styrene with acrylonitrile (AN) initiated with 2-methyl-2-undecanethiol (RSH) was investigated.
Abstract: The copolymerization of styrene (St) with acrylonitrile (AN) initiated with 2-methyl-2-undecanethiol (RSH) was investigated. Kinetic studies revealed that the initial rate of the copolymerization, which does not occur spontaneously in the absence of RSH, obeys the following expression: Rp ∝ [RSH]x, where x is 0,5 when [RSH] ranges from 3,4.10−4 to 3,4.10−3 mol/l and 0 when [RSH] is larger than 3,4.10−3 mol/l. The initial copolymerization rate, Rp, increases with increasing percentage of AN in the monomer feed. From the slope of ln Rp vs. 1/T, the apparent activation energy, Eapp, was calculated to be 17 kJ/mol in the temperature range of 30°C to 50°C. RSH is the only initiating species, and it also plays a role as chain-transfer agent. The value of Mw/Mn, which varies from 1,5 to 2,0, is typical of a free-radical poymerization. The reactivity ratios were calculated to be rSt = 0,42 ± 0,04 and rAN = 0,02 ± 0,03. It seems to be unnecessary to introduce a penultimate effect for explaining the experimental data.

Journal ArticleDOI
TL;DR: In this paper, internal friction and frequency during the course of bainitic transformations in 18Cr2Ni4WA steel and Cu-2583Zn-396Al(wt%) alloy are measured.

Journal ArticleDOI
TL;DR: In this article, the postbuckling behavior of simply supported rectangular orthotropic plates under inplane compression is investigated, and two types of in-plane boundary conditions are considered and the effects of initial imperfections are also studied.
Abstract: In this paper, applying perturbation method to von Karman-type nonlinear large deflection equations of orthotropic plates by taking deflection as perturbation parameter, the postbuckling behavior of simply supported rectangular orthotropic plates under inplane compression is investigated. Two types of in-plane boundary conditions are now considered and the effects of initial imperfections are also studied. Numerical results are presented for various cases of orthotropic composite plates having different elastic properties. It is found that the results obtained are in good agreement with those of experiments.

Journal ArticleDOI
TL;DR: In this article, a pulsed ultra-high magnetic field was used to induce the athermal martensitic transformation in an Fe-Ni-4Mn (wt%) alloy.
Abstract: Magnetic field-induced transformation from paramagnetic austenite to ferromagnetic martensite in an Fe-21Ni-4Mn (wt%) alloy with dual martensitic transformation kinetics has been studied by magnetization measurement and optical microscopy, applying a pulsed ultra-high magnetic field. As a result, the following were found. A magnetic field higher than a critical one is needed to induce the martensitic transformation above Ms. The critical magnetic field increases with increasing temperature, and when plotted against the temperature difference (ΔT) from Ms, it lies on a straight line not passing through the origin. This result and thermodynamical analysis suggest that pulsed magnetic field strongly promotes the athermal martensitic transformation and restrains the isothemal one. The influence of magnetic field on martensitic transformation in the present Fe-Ni-Mn alloy is mainly due to Zeeman effect. The entropy change for athermal transformation at Ms, ΔSΔMsat is obtained to be 4.13 J/mol·K. The amount of magnetic field-induced martensites increases linearly with the maximum strength of pulsed magnetic field. Lath, plate and butterfly martensites are formed under magnetic field.

Journal ArticleDOI
TL;DR: In this paper, the dislocation structures of directionally solidified Rene 80 superalloy in the γ′ phase during tensile deformation at 760 and 850°C, and during creep deformation under a stress of 618 MPa have been studied by transmission electron microscopy.
Abstract: The dislocation structures of directionally solidified Rene 80 superalloy in the γ′ phase during tensile deformation at 760 and 850°C, and during creep deformation at 760°C under a stress of 618 MPa have been studied by transmission electron microscopy. It has been shown by an extensive analysis of the dislocations bounding a superlattice stacking fault that γ′ shearing occurs by viscous slip of pairs of 1 3 〈112〉 superpartials separated by superlattice intrinsic stacking faults (SISFs) but the 1 2 〈110〉 screw components of these have moved away from the 1 6 〈112〉 edge components on the [111] plane, leaving a stress-stabilized antiphase boundary in its wake in tensile deformation. In contrast with the tensile glide mechanism, in creep deformation γ′ shearing occurs by viscous slip of pairs of SISF-separated 1 3 〈112〉 superpartials with net slip vector 〈110〉 while the cores of the 1 3 〈112〉 superpartials do not appear to be separated.

Journal ArticleDOI
TL;DR: In this article, the multiple transverse crack problem of [ 0° n /90° m ] s laminates is considered and the problem is formulated in terms of a singular integral equation.

Journal ArticleDOI
TL;DR: In this article, a generalized grand-canonical nonequilibrium density operator of maximal entropy was proposed to define intensive variables of discrete nonequilibria. But the definition of intensive variables is not restricted to discrete systems.
Abstract: Intensive variables of discrete nonequilibrium systems are defined by inequalities which are derivable quantumstatistically for contacts between discrete equilibrium and nonequilibrium systems. These contacts are described by a generalized grand-canonical nonequilibrium density operator of maximal entropy by which heat-, mass-, and power-exchange through the contact can be evaluated. A straightforward calculation yields inequalities whose interpretation enables definitions of intensive nonequilibrium quantities for discrete systems.

Journal ArticleDOI
TL;DR: A linear-phase digital filter system using a dual RRS structure for audio tone control is presented that has very low arithmetic complexity, and can thus be implemented in real time.
Abstract: A linear-phase digital filter system using a dual RRS structure for audio tone control is presented. It has very low arithmetic complexity, and can thus be implemented in real time.

Journal ArticleDOI
TL;DR: In this paper, the dislocation structures of directionally solidified (DS) Rene 80 superalloy in γ′ phase during tensile deformation at 760°C and 850°C under a stress of 618MPa have been studied by transmission electron microscopy.

Journal ArticleDOI
TL;DR: In this paper, a consistent theory for torsion of thin-walled bars with cross-sections of arbitrary shape (open, closed or mixed) is developed, and the basic relations, formulas and equations are derived and proved under the consistent assumptions.
Abstract: A consistent theory for torsion of thin-walled bars with cross-sections of arbitrary shape (open, closed or mixed) is developed in this paper; it is an improvement on the classical torsion theory of thin-walled bars. All the basic relations, formulas and equations are derived and proved under the consistent assumptions. A torsional stiffness matrix for thin-walled bar elements is also formulated on the basis of the consistent theory. A computer program has been written which is applicable to the practical use of torsional analysis of thin-walled bar structures with arbitrary cross-sections.

Journal ArticleDOI
TL;DR: In this article, an approach using plane strain solutions is presented to calculate stress intensity factors for one or more internal or external radial cracks in circular cylinders and other simply closed cylindrical bodies with symmetric geometry and loading conditions.

Journal ArticleDOI
TL;DR: In this paper, a laser scanning microdisplacement detection system was developed to measure the thermal expansion coefficient of materials over the range from room temperature to 1200 K. The measurement apparatus consists of a dynamic heating device, a microdisposition detection system, and a microcomputer-based high-speed data acquisition system.
Abstract: A laser scanning microdisplacement detection system has been developed to measure the thermal expansion coefficient of materials over the range from room temperature to 1200 K. The measurement apparatus consists of a dynamic heating device, a microdisplacement detection system, and a microcomputerbased high-speed data acquisition system. The specimen is dynamically heated from room temperature to 1200 K by passing a large electrical current through it. The thermal expansion of the specimen is detected by the laser detection system, which records the shift of Fraunhofer diffraction fringes with a photodetector. Measurements of the mean linear thermal expansion coefficient of 1Cr18Ni9Ti stainless steel in the range of 300–1200 K are described. The results are compared with other reported values of the thermal expansion coefficient. The maximum deviation between them is about 2.3% at the highest temperature, 1200 K.

Journal ArticleDOI
TL;DR: In this paper, the stability problem of a torque-free multibody system with spherical joints is discussed by use of Liapunov's direct method, and it is proven that the permanent rotation of such a system about the coincident axis of symmetry is always stable.
Abstract: The stability problem of the permanent rotation of a torque-free multibody system with spherical joints is discussed by use of Liapunov's direct method. The system is described by the Hooker-Margulies equations in vector-dyadic form, and there exist the integrals of angular momentum and of energy for the torque-free case. The first integrals obtained are used to establish the Liapunov function, then a stability criterion in analytical form is found for the system composed of two symmetrical bodies coupled by a frictionless joint. It is proven that the permanent rotation of such a system about the coincident axis of symmetry is always stable.