Showing papers by "Xi'an Jiaotong University published in 1983"
TL;DR: In this article, the authors compared CO and N2 as a buffer in gas mixtures and extended the studies to a nearly uniform field gap and a highly non-uniform field gap.
Abstract: In a previous paper[8] breakdown strengths of c-C4F8/SF6/CO gas mixtures in various proportions were reported for a 30mm rod-sphere gap under ac and impulse voltages. A mixture of 1% c-C4F8 + 59% SF6 + 40% CO exhibited higher dielectric strength than pure SF6 in the pressure range between 350 and 400 kPa. The present paper compares CO and N2 as a buffer in gas mixtures and extends the studies to a nearly uniform field gap and a highly non-uniform field gap. Additional experiments comfirmed that the use of CO as a buffer in gas mixtures is superior to N2 and that some c-CZF8/SF6/CO gas mixtures have higher dielectric strength and are cheaper than pure SF6.
17 citations
TL;DR: In this paper, the authors established the partial differential equation and properly pose conditions for the stream function on an arbitrary stream surface in a turbomachine using tensor analysis and a semi-geodesic coordinate system.
13 citations
TL;DR: In this paper, a new system decomposition-aggregation technique is proposed to decompose the power system into subsystems and then to aggregate the subsystems by interconnection boundary conditions.
Abstract: An on-line transient stability evaluation method is presented in this paper. Under some classical assumptions, the change of generator rotor angles during the transient period is described by a set of second order differential equations. This set of equations is solved by single-step high order derivative explicit integration. A new system decomposition-aggregation technique is proposed to decompose the power system into subsystems and then to aggregate the subsystems by interconnection boundary conditions. Based on the aggregation model, the calculation of high-order derivatives is quite efficient to reduce the requirements of both computer memory and computational time for a large scale power system. The relation of memory and execution time requirements to the system decomposition is discussed. Two systems, the IEEE 118 bus test system with 34 generators and a 293 bus system with 63 generators, are tested by simulation on a CDC-6600 computer. The results demonstrate that the proposed method is effective for on-line application and may be faster than Liapunov's direct method.
11 citations
9 citations
23 May 1983
TL;DR: In this paper, an analysis of the electromagnetic coupling between two arbitrarily oriented dipoles through planar multilayered shields is made, based on the plane-wave spectral representation of radiation fields and the use of transformation matrices for multi-layered media.
Abstract: : An analysis of the electromagnetic coupling between two arbitrarily oriented dipoles through planar multilayered shields is made. This method of approach is based on the plane-wave spectral representation of radiation fields and the use of transformation matrices for multilayered media. Numerical results are found to be in good agreement with the experimental data obtained in the frequency range from 10 kHz to 1 MHz. (Author)
7 citations
2 citations
01 Jan 1983
TL;DR: In this article, the authors present a comprehensive theoretical analysis and experimental verification for the law of influence of the relative billet length specified by Lo/d on cropping quality, and also offer some new opinions about the practical applications and development of the introduced technology.
Abstract: This paper is a continuation and development of “The Study of Precision Bar Cropping Under Axial Load”* /1/. It presents a comprehensive theoretical analysis, and experimental verification for the law of influence of the relative billet length specified by Lo/d on cropping quality. It also offers some new opinions about the practical applications and development of the introduced technology. The paper includes the following four main parts: Influence of the relative billet length on geometric distortion; Velocity field for varied relative lengths; Mechanical analysis and experimental investigation of the cropping of ultra-short billets; The precision cropping of profiled bars under axial load; The development of precision cropping approach under axial load.
1 citations
1 citations
TL;DR: It is proved that the extended fuzzy operators are also t(s)-norms for a new ordering and the fuzzy truth-valued possibility degree for a fuzzy (σ-algebra) is introduced.
1 citations
TL;DR: A net-making method for fuzzy clustering analysis is obtained and a method for clinical data reduction is considered that uses the concept of fuzzy clustered.
TL;DR: In this article, the authors introduced the studies of population control in China, such as dynamic models, identification, some formulations of population indexes, forecasting, the inertia of population growth, stability, population control and economic surplus, the decision-making for target population size, synthesis, optimization, large scale systems structure and allocation-coodination.
TL;DR: In this paper, Wei-zang et al. obtained the first-order asymptotic solution to a system of equations for a nonlinear diffusion process, thus simplifying and improving the previous work considerably.
Abstract: In this paper, by using Chien Wei-zang — Latta's composite expansion method[5], we have obtained the first-order asymptotic solution to a system of equations for a nonlinear diffusion process, thus simplifying and improving the previous work[4] considerably. Moreover, a kind of complete analytical solution has been given for a special case, and the periodic solution at the bifurcation point has been discussed, the related results being in agreement with the experiments.
14 Apr 1983
TL;DR: The proposed method based on extraction of sound-stimulation emphasizes phoneme-phoneme transition properties within syllable, and has proved effective and feasible in experiment for Chinese speech recognition.
Abstract: In this paper, a syllable-based Chinese speech recognition system is described which consists of components for carrying out three main tasks: syllable segmentation, acoustic analysis and training. Connected speech is first divided into syllabic units, and an efficient short-time FFT algorithm with two different analysis frame sizes is then used to analyse the units in order to find the dynamic spectrum of syllables. Finally an important feature, sound-stimulation, is extracted from syllable dynamic spectrum and assembled in one feature matrix for each syllable. The proposed method based on extraction of sound-stimulation emphasizes phoneme-phoneme transition properties within syllable, and has proved effective and feasible in experiment for Chinese speech recognition.