Showing papers by "Tsinghua University published in 1980"
TL;DR: In this article, a ternary piezoelectric ceramics transformer with a voltage step-up ratio of about 150-200 was presented, and the experimental results made on the material properties and the characteristics of transformer elements are presented.
Abstract: This paper presents a piezoelectric ceramic transformer which has a no-load alternating current voltage step-up ratio of about 150–200. The composition of the material is: ternary piezoelectric ceramics. The experimental results made on the material properties and the characteristics of transformer elements are presented. Based on the analysis of scanning electronic microscope and X-ray diffraction, the relations between physical properties and microstructure of piezoelectric ceramics were studied. With laser holography, under high voltage, the vibration modes of the transformer elements were measured. Amplitude distributions of vibration modes were quantitatively computed. The results were related with the voltage step up ratio. Analysis and comparison were made between vibration modes. The bar samples were used as transverse-type piezoelectric transformer elements. The specimens were made in disks of 8 × 0.8 mm and bars of 120 × 26 × 3 mm.
28 citations
TL;DR: In this article, an exact solution for the bending of uniformly loaded rectangular cantilever plates by using the idea of generalized simply supported edge together with the method of superposition is given, and the results are compared with those obtained from approximate methods to confirm the validity of the method presented.
Abstract: An exact solution is given for the bending of uniformly loaded rectangular cantilever plates by using the idea of generalized simply supported edge together with the method of superposition. As illustrative examples, a square plate and a rectangular plate with the ratio of the clamped edge to the neighbouring free edge equal to two are solved numerically. The results are compared with those obtained from approximate methods to confirm the validity of the method presented.
27 citations
TL;DR: By means of modified iteration method, the authors gives approximate solution of the large deflection equations of circular corrugated plate with sine-shaped shallow waves having a central platform under uniform lateral load.
Abstract: By means of modified iteration method, this paper gives approximate solution of the large deflection equations of circular corrugated plate with sine-shaped shallow waves having a central platform under uniform lateral load A formula of initial modification coefficient β is given, and an integral is obtained for the simplification of modified iteration calculations The results of present paper show better agreement with experimental data and larger applicable range than all other existing solutions of corrugated plates
23 citations
01 Jan 1980
TL;DR: In this paper, the Krawczyk-Moore algorithm was generalized to the problem of computing a sequence of interval vectors from a given initial interval vector, and a computational test for existence, uniqueness, and convergence was proposed.
Abstract: Publisher Summary This chapter describes the generalization of the Krawczyk–Moore algorithm It presents the Krawczyk–Moore algorithm for producing a sequence of interval vectors from a given initial interval vector It also reviews a computational test for existence, uniqueness, and convergence The proof of the convergence of an interval algorithm is similar to the proof of a theorem It is found that instead of F in the algorithm, a narrower interval matrix function g has been given The quadratic convergence may be proved under reasonable conditions, and it is clear that the results obtained may be applied to the interval procedure It is found that as long as Krawczyk–Moore algorithm converges to a point z , the point z is the unique solution of the f ( x ) = 0 in X (0)
22 citations
TL;DR: In this paper, the general solutions of axial symmetrical ring shells for all values of slenderness ratio were given, and they can be used to solve various practical problems, including corrugated tubes, thermal expansion joints, Borden tubes, etc.
Abstract: This paper gives the general solutions of axial symmetrical ring shells for all values of slenderness ratio. This solution is newly brought out, and can be used to solve various practical problems, including corrugated tubes, thermal expansion joints, Borden tubes, etc.
17 citations
TL;DR: In this paper, the application of hot-pressed Si 3 N 4 as cutting tool was carried out and satisfactory results achieved in cutting hardened tool steels, chilled cast iron, pure molybdenum and pyrolytic graphite.
9 citations
TL;DR: In this paper, a wave method has been applied to analyze and derive the dispersion equation for hollow cylindrical ECM's, which features in simpler mathematics and clearer physical interpretation.
Abstract: A wave method has been applied to analyze and derive the dispersion equation for hollow cylindrical ECM's, which features in simpler mathematics and clearer physical interpretation. Besides, the effects of space charge Columb field have been taken into account. For the time being, the result is more likely suitable for fundamental mode interaction.
7 citations
TL;DR: In this article, the explicit forms of field functions in tetrehedron elements with 16 and 20 degrees of freedom are given in terms of volume coordinatesL 1,L 2,L 3,L 4 of tetrahedron.
Abstract: In this paper, the explicit forms of field functions in tetrehedron elements with 16 and 20 degrees of freedom are given in terms of volume coordinatesL1,L2,L3,L4 of tetrahedron.
3 citations
01 Jan 1980
TL;DR: In this article, a laser technique was developed for the purpose of investigating the movement of particles in a gas-fluidized bed and some noteworthy results were obtained; however, the results were limited to the case of a single particle.
Abstract: A laser technique was developed for the purpose of investigating the movement of particles in a gas-fluidized bed and some noteworthy results were obtained.
2 citations
TL;DR: In this article, sufficient conditions for oscillation of generalized Lienard equations were given, which generalize the results of [1, 7] and [8], respectively.
Abstract: Some sufficient conditions for oscillation of the generalized Lienard equations $${⩀t x}=h(y)-F(x),$$ $${⩀t y}=-g(x)$$ are given, which generalize the results of [1–7].
1 citations
TL;DR: In this article, the lifetime of the most reactive intermediate in the mechanism from mathematical derivations on simple reaction models was found as the maximum permitted stepsize, and a steady state approximation on this reactive intermediate may relieve this limitation and save computer's computation time.
Abstract: Constant-stepsized computer simulation of chemical reactions gives unreasonable results when the accepted stepsize exceeds a limit. The maximum permitted stepsize is found as the lifetime of the most reactive intermediate in the mechanism from mathematical derivations on simple reaction models. Steady state approximation on this reactive intermediate may relieve this limitation and save computer's computation time. This approximation method has been satisfactorily applied to the simulation of the thermal decomposition of methane.