Showing papers by "Tsinghua University published in 1988"
TL;DR: An algorithm is developed and computer coded for failure-diagnosis-system design using a robust observation approach that can locate system failures to first-order components without a priori information on possible failure types.
Abstract: A new concept of faulty component detection via robust observation is proposed. An algorithm is developed and computer coded for failure-diagnosis-system design using a robust observation approach. Such diagnosis systems can locate system failures to first-order components without a priori information on possible failure types.
171 citations
TL;DR: In this paper, the authors measured the rate of CH3OH synthesis on a series of Cu ZnO and related catalysts prepared by different techniques under reaction conditions of 523 K, 50 atm, and H2/CO/CO2 = 70/24/6.
125 citations
01 Jul 1988-Graphical Models \/graphical Models and Image Processing \/computer Vision, Graphics, and Image Processing
TL;DR: In this new depth recovery method, an arbitrary depth must be first preset for a point somewhere in the image, then path-independent line integrals are computed to get the relative depths at every pont in theimage.
Abstract: This paper describes a new method for constructing a depth map from surface normals. In this new depth recovery method, an arbitrary depth must be first preset for a point somewhere in the image, then path-independent line integrals are computed to get the relative depths at every pont in the image. The validity of the proposed method is discussed and its efficiency was tested using surface normals obtained by shape from a shading algorithm. The comparison of the new method to the previous ones is given. Theoretical analysis and experimental results show that our method is both powerful and easy to implement.
89 citations
TL;DR: In this article, a systeme de couplage entre elements finis et infinis, for a vallee de forme semi-cylindrique, is proposed.
Abstract: Utilisation du systeme de couplage entre elements finis et infinis, pour une vallee de forme semi-cylindrique; les conditions geologiques (couches moins resistantes) amplifient les mouvements, suggerant que l'excavation d'une roche alteree ameliorera non seulement la stabilite mais la reponse dynamique d'un barrage voute
58 citations
TL;DR: An optimality condition theorem and an algorithm for nonlinear minimum-cost network flow are proposed and the results show that the proposed method is very fast compared to existing methods.
Abstract: An optimality condition theorem and an algorithm for nonlinear minimum-cost network flow are proposed. A computational network model for optimal daily scheduling of cascaded plants (ODSCP) is established, and an algorithm for searching the minimum-cost flow-augmenting path and the maximum-cost flow-reducing path in the computational network model of ODSCP is described. Digital computations are carried out and the results show that the proposed method is very fast compared to existing methods. >
57 citations
TL;DR: A parallel localized algorithm to calculate the Euler number of a given binary image on a square grid, is presented and is proven by employing graph theory.
52 citations
TL;DR: In this article, a numerical algorithm which combines the Newton-Raphson scheme and low relaxation iteration has been developed for solving the general transient line contact elastohydrodynamic lubrication (EHL) problem.
50 citations
TL;DR: In this article, it was shown that the amplitude of the gain curve is reduced as the mode split happens, and the frequency difference between the two modes varies periodically with the quartz plate's rotation over a range of one longitudinal mode separation.
45 citations
14 Nov 1988
TL;DR: In this paper, a method for constructing a depth map from surface normals is described, where an arbitrary depth must first be preset for a point somewhere in the image, and then path-independent line integrals are computed to get the relative depths at every point in an image.
Abstract: A method for constructing a depth map from surface normals is described. In this depth recovery method, an arbitrary depth must first be preset for a point somewhere in the image, and then path-independent line integrals are computed to get the relative depths at every point in the image. The validity of the proposed method is discussed and its efficiency is tested using surface normals obtained by shape from the shading algorithm. A comparison to previous methods is made. Theoretical analysis and experimental results show that the present method is both powerful and easy to implement. >
42 citations
TL;DR: In this paper, the friction and wear mechanisms of plasma-sprayed ceramic coatings (Cr2O35%SiO23%TiO2, Cr3C212%Ni3%Cr, TiO2), made in China, were studied at high temperature (450 °C).
42 citations
TL;DR: Etude theorique et experimentale de la lubrification elastohydrodynamique avec de la graisse as discussed by the authors, a.k.a. elasthydrodynamiques.
Abstract: Etude theorique et experimentale de la lubrification elastohydrodynamique avec de la graisse
TL;DR: In this article, a simplified governing equations and corresponding boundary conditions of flexural vibration of viscoelastically damped unsymmetrical sandwich plates are given, and the asymptotic solution of the equations is discussed.
TL;DR: In this paper, the authors measured the yields of methanol, higher alcohols, and hydrocarbons during CO hydrogenation on a Cu/Co/ZnO/Al{sub 2}O{sub 3}/K catalyst.
TL;DR: In this paper, the strength effect of the F mineral admixture (FMA) which is made of the finely divided powder of natural Zeolite Rock ground with a bit of other inorganic material was investigated.
TL;DR: In this paper, a fiber ring resonator constructed by a strand of singlemode fiber and a mechanically lapped directional coupler was used as a high-resolution optical spectrum analyser.
Abstract: A fibre ring resonator constructed by a strand of single-mode fibre and a mechanically lapped directional coupler is demonstrated. The finesse of the resonator was measured to be as high as 1260. Methods to improve the coupler characteristics are discussed. The device can be used as a highresolution optical spectrum analyser.
01 Jun 1988
TL;DR: In this paper, a mathematical model of the cardiovascular system was developed to predict the effects of acceleration stress on peripheral and central vision, which was used to study the relative effectiveness of several acceleration protection methods and devices, including an anti-G suit design.
Abstract: Engineering methodology was used to develop a mathematical model of the cardiovascular system which is capable of predicting the effects of acceleration stress on peripheral and central vision. The basic model, previously reported, has been extended to include a simulation of the venous system and a number of additional refinements. It includes simulations of the heart, arterial, and venous system, physiologic compensatory mechanisms, and the effects of protective devices and maneuvers. Information derived from the model is important to understanding of cardiovascular responses to acceleration stress, mechanisms which determine tolerance, and factors which limit a pilot's performance. The model has been used to study the relative effectiveness of several acceleration protection methods and devices, including an anti-G suit design. Results from simulations using the model correlate well with reports in the literature. >
TL;DR: Based on the generalized compatibility condition under constant and linear stress field, a quadrilateral generalized conforming isoparametric element, GC-Q6, was developed for plane stress analysis as mentioned in this paper.
Abstract: Based on the generalized compatibility condition under constant and linear stress field, a quadrilateral generalized conforming isoparametric element, GC-Q6, for plane stress analysis, is developed The element GC-Q6 can be regarded as an improved form of Wilson's non-conforming isoparametric element Q6 GC-Q6 can pass the patch test for arbitrary irregular mesh while Q6 can not GC-Q6 degenerates to Q6 when it is a parallelogram Numerical examples show that the GC-Q6 element gives more accurate stress solution than the existing non- conforming elements and is less sensitive to geometric distortion
TL;DR: In this article, the surface and interior compositions of large single and twinned ZSM-5 crystals were studied by electron microprobe analysis, and the aluminium distribution across an individual crystal plane surface was found to be uniform.
TL;DR: In this paper, a method is proposed to determine the parameters in the exponential expression of the mass diffusivity according to the mean mass diffusion, and experimental results from wet sand are compared with the predicted curves.
12 Sep 1988
TL;DR: In this article, the frequency spectra of acoustic emission (AE) of PD in six kinds of typical oil gaps were designed and tested to simulate partial discharges (PD) in the insulation of power transformers.
Abstract: Six kinds of typical oil gaps were designed and tested to simulate partial discharges (PD) in the insulation of power transformers. The frequency spectra of acoustic emission (AE) of PD in those gaps were presented and investigated with a computer-aided measuring system. The attenuation of AE and the variation of its frequency spectrum in oil and in oil-impregnated paper were studied. Peak frequencies in the frequency spectra of AE of PD in these gaps were distributed in the 70-150-kHz range. Based on test results, the frequency bandwidth of 70-180 kHz was recommended for the AE measuring system of PD detection in power transformers. >
TL;DR: In this article, root-mean-square and Laplacian mode field radius (MFR) definitions for planar single-mode optical waveguides (PSMOW) with arbitrary index profile are proposed based on the second moment of the near-field (NF) and far-field distributions.
Abstract: Root-mean-square and Laplacian mode field radius (MFR) definitions for planar single-mode optical waveguides (PSMOW) with arbitrary index profile are proposed based on the second moment of the near-field (NF) and far-field (FF) distributions. Expressions of these definitions in both NF and FF, as well as their simple relations to the propagation constant and splice loss between two identical waveguides, are derived.
01 Nov 1988-Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment
TL;DR: In this paper, a direct Monte Carlo (DMC) calculation of the complete response functions of Si(Li) detectors for low energy X-rays (keV) is proposed.
Abstract: A direct Monte Carlo (DMC) calculation of the complete response functions of Si(Li) detectors for low energy X-rays (keV) is proposed. Interaction mechanisms for X-rays in the sensitive volume of the detector and in the surrounding material are investigated in detail. Response functions at several energy values are calculated and compared with the corresponding experimental ones. The present approach uses a detailed simulation of individual interactions rather than the simple range formulation used by Gardner et al. [Nucl. Instr. and Meth. A242 (1986) 399] and gives better results in some cases. The physical model and calculation method presented here can be applied widely to low energy X-ray fluorescence analysis and other complicated photon spectrum analyses. In principle it is also suited for Ge detectors.
TL;DR: An icosahedral phase has been observed for the first time in the equilibrium immiscible Fe-Cu system as discussed by the authors, formed by directed xenon ion mixing of Fe/Cu multilayers at room temperature and without any amorphous-to-quasi-crystalline phase transition.
Abstract: An icosahedral phase has been observed for the first time in the equilibrium immiscible Fe-Cu system. The new metastable phase was formed by directed xenon ion mixing of Fe/Cu multilayers at room temperature and without any amorphous-to-quasi-crystalline phase transition. The atomic concentration of this phase was determined by in situ energy-dispersive spectroscopy (EDS) to be around Fe60Cu40.
TL;DR: In this paper, the chemical surface film of a plasma-sprayed ceramic coating (Cr 3 C 2, Al 2 O 3 13%TiO 2 ), formed by the reaction of the additives, calcium, sulphur and phosphorus, with a ceramic surface at high temperature, has been studied using scanning electron microscopy, Auger electron spectroscopy and microregion X-ray diffraction.
TL;DR: In this article, three dual conservation laws are generated with the aid of a version of Noether's theorem on invariant variational principle in conjunction with the principle of stationary complementary potential energy.
TL;DR: In this article, a simple and systematic procedure for decentralized stabilizer design for multimachine systems is presented, which first selects the most effective location of a stabilizer according to a machine stability index.
TL;DR: Magnetron cosputtering from different sources has been employed to study the metallic glass formation as discussed by the authors, and the thin films of these three alloys were cosputtered onto various substrates cooled either with or without liquid nitrogen.
TL;DR: In this paper, the stress intensity factors of Reissner plates are calculated by the sub-region mixed finite element method, and the relative errors are less than 1% for some finite and infinite plates.
TL;DR: In this paper, a method is proposed for evaluation of the mass diffusivity Dm(w, t), thermo-mass diffusivities D,m, t, w, t, non-linear thermal conductivity ξ(w and t), and mass-thermal conductance α(w, t) of moist porous media at different temperatures and moisture contents.