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1991 Vol. 13, No. 3
Display Method:
1991, 13(3): 225-231.
Abstract:
It is suggested to study the neural network in the view of neural functions. The memory function of network is studied and its mathematical model is given. The model is synthesized by a peicewise-linear resistive network. The network is of many properties of artificial network such as parallelism, real-time processing, distributivity and adaptability etc., in addition, the parameters of network are expressed analytically by the patterns and features which are memorized in the network.
It is suggested to study the neural network in the view of neural functions. The memory function of network is studied and its mathematical model is given. The model is synthesized by a peicewise-linear resistive network. The network is of many properties of artificial network such as parallelism, real-time processing, distributivity and adaptability etc., in addition, the parameters of network are expressed analytically by the patterns and features which are memorized in the network.
1991, 13(3): 232-241.
Abstract:
From practical point of view, the Siegenthaler s definition of correlation immunity is improved. Under the new definition there exists no trade-off between the generalized correlation immunity and linear complexity of the output key streams. The famous Bent functions are used for the study of entropy immunity in feedforward netforks. New results and new methods are also presented.
From practical point of view, the Siegenthaler s definition of correlation immunity is improved. Under the new definition there exists no trade-off between the generalized correlation immunity and linear complexity of the output key streams. The famous Bent functions are used for the study of entropy immunity in feedforward netforks. New results and new methods are also presented.
1991, 13(3): 242-249.
Abstract:
Two k-hyperconnection expressions of a general k-order cofactor Y(ij) are presented for the indefinite parameter matrix Y of a linear system, and based on it, a decomposition theorem of Y(ij) is dcrived. By this theorem, the multi-level tearing and analysis can be carried out easily for any large linear system. This is a new multi-level topological analysis method. Using the method the scale of systems which can be topologically analysed by a computer will be increased.
Two k-hyperconnection expressions of a general k-order cofactor Y(ij) are presented for the indefinite parameter matrix Y of a linear system, and based on it, a decomposition theorem of Y(ij) is dcrived. By this theorem, the multi-level tearing and analysis can be carried out easily for any large linear system. This is a new multi-level topological analysis method. Using the method the scale of systems which can be topologically analysed by a computer will be increased.
1991, 13(3): 250-254.
Abstract:
Based on image decomposition and adaptive hybrid vector quantization, a high-compression image coding scheme is presented. The coding method of low-pass com-ponent by adaptive hybrid vector quantization is described in detail. As far as low-pass com-ponent is concerned, the acceptable result can be obtained by this scheme with compression ratio higher than 80:1.
Based on image decomposition and adaptive hybrid vector quantization, a high-compression image coding scheme is presented. The coding method of low-pass com-ponent by adaptive hybrid vector quantization is described in detail. As far as low-pass com-ponent is concerned, the acceptable result can be obtained by this scheme with compression ratio higher than 80:1.
1991, 13(3): 255-262.
Abstract:
Binary code signal have been widely used in various radars due to their simple implementation, but the selection of the binary codes with high compression ratio and low sidelobes is not well solved, because of the difficult processing in mathematics and expensive calculation cost. In this paper, neural computing is introduced into the field of the selection of binary codes, and a new method based on simulated annealing is proposed. The experiments show that the proposed method is able to select the optimal binary codes with much less time than the known methods, furthermore the optimization of selection of the binary codes versus the calculation cost trade-off is easier.
Binary code signal have been widely used in various radars due to their simple implementation, but the selection of the binary codes with high compression ratio and low sidelobes is not well solved, because of the difficult processing in mathematics and expensive calculation cost. In this paper, neural computing is introduced into the field of the selection of binary codes, and a new method based on simulated annealing is proposed. The experiments show that the proposed method is able to select the optimal binary codes with much less time than the known methods, furthermore the optimization of selection of the binary codes versus the calculation cost trade-off is easier.
1991, 13(3): 263-270.
Abstract:
A new approach called perrurbation theory is presented to analyze the electri-cal impedance for medicine. The formula of constant voltage and constant current field per-turbation, modified G-L formula and the formula of electrical field perturbation evoked by sound field are derived. The applicafion resnlts of the theory in electroglottographic method are also introduced.
A new approach called perrurbation theory is presented to analyze the electri-cal impedance for medicine. The formula of constant voltage and constant current field per-turbation, modified G-L formula and the formula of electrical field perturbation evoked by sound field are derived. The applicafion resnlts of the theory in electroglottographic method are also introduced.
1991, 13(3): 271-277.
Abstract:
In general, in free electron lasers there two kinds of stimulated radiations. FEL radition and cyclotron ralition. It is shown theoretically, if the initial transverse velocity of electron is large and the selected parameters for FEL are not suitable, the cyclotron radiation will be dorninant, especially when the energy of electron beam is low. But the cyclotron radiation does not have double Doppler frequency up-shift effect, is frequency is limited by axial magnetic field, when the energy of electron beam is low. But the cyclotron radiation does not have double Doppler frequency up-shift effect, is frequency is limited by axial magnetic field, when the energy of electron beam is high, the cyclotron radiation frequency will be much lower than FEL radiation frequency. Therefore, in FEL experiments how to distinguish these two kinds of radiations and to suppress the cyclotron radiation are very important.
In general, in free electron lasers there two kinds of stimulated radiations. FEL radition and cyclotron ralition. It is shown theoretically, if the initial transverse velocity of electron is large and the selected parameters for FEL are not suitable, the cyclotron radiation will be dorninant, especially when the energy of electron beam is low. But the cyclotron radiation does not have double Doppler frequency up-shift effect, is frequency is limited by axial magnetic field, when the energy of electron beam is low. But the cyclotron radiation does not have double Doppler frequency up-shift effect, is frequency is limited by axial magnetic field, when the energy of electron beam is high, the cyclotron radiation frequency will be much lower than FEL radiation frequency. Therefore, in FEL experiments how to distinguish these two kinds of radiations and to suppress the cyclotron radiation are very important.
1991, 13(3): 278-285.
Abstract:
The scattering properties of the composite cylinders are discussed. Some integral equations are established, then the monent method is used to solve the surface currents under TM and TE polarization separately. After appropriate arrangement, the computer programs have been compiled general use. Finally, some calculation examples are given. The obtained resu-Its are compared with the published data. They are in good agreements.
The scattering properties of the composite cylinders are discussed. Some integral equations are established, then the monent method is used to solve the surface currents under TM and TE polarization separately. After appropriate arrangement, the computer programs have been compiled general use. Finally, some calculation examples are given. The obtained resu-Its are compared with the published data. They are in good agreements.
1991, 13(3): 286-292.
Abstract:
Based on improved charge conttrol model and combining GSW velocity-field equation, a series of analytical solutions for the static characteristics of HIGFETs such as TD-VD-VG,Gm and CG are derivel. The results of calculations are compared with experimental data reported in references, within the rang of VG2V, ID TDS, they agree very well. It is pionted out that two-lengrh model must be considered in the high field region due to greater leakage current between the gate and rhe drain. The effects of temperature on Vth, and the effects of gate length and width, temperature, GaAlAs thickness, source resistance, GaAs mobility on Gm are discussed. Possible approaches for improving performances of HIGFETs are pointed out according to the above analyses.
Based on improved charge conttrol model and combining GSW velocity-field equation, a series of analytical solutions for the static characteristics of HIGFETs such as TD-VD-VG,Gm and CG are derivel. The results of calculations are compared with experimental data reported in references, within the rang of VG2V, ID TDS, they agree very well. It is pionted out that two-lengrh model must be considered in the high field region due to greater leakage current between the gate and rhe drain. The effects of temperature on Vth, and the effects of gate length and width, temperature, GaAlAs thickness, source resistance, GaAs mobility on Gm are discussed. Possible approaches for improving performances of HIGFETs are pointed out according to the above analyses.
1991, 13(3): 293-298.
Abstract:
Motion of an electron across an alpha magnetic mirror system with arbitray incident conditions is studied. It is found that when the central trajectory is given, any other trajectories can be distinguished as normai and abnormal ones. Electrons moving along normal trajectories accept filtering of momentum filter slit, while the others along abnormal trajectories will not. The method of computing the projections onto the central trajectory co-ordinate system of a differential arc element along normal trajectory is given, which is numerically demonstrated with enough precision. This work is of significance for understanding the details of motion of charged particle beam across alpha magnetic mirror system.
Motion of an electron across an alpha magnetic mirror system with arbitray incident conditions is studied. It is found that when the central trajectory is given, any other trajectories can be distinguished as normai and abnormal ones. Electrons moving along normal trajectories accept filtering of momentum filter slit, while the others along abnormal trajectories will not. The method of computing the projections onto the central trajectory co-ordinate system of a differential arc element along normal trajectory is given, which is numerically demonstrated with enough precision. This work is of significance for understanding the details of motion of charged particle beam across alpha magnetic mirror system.
1991, 13(3): 299-303.
Abstract:
A graphic svstem of superconductor models developed by the aid of a basie IBM-PC microcomputer is presented. This system has been designed to store informarion on structures and properties of superconductors and related compounds discovered so far, to display and plot three dimensional crystallographic structure and coordination polyhedron structure, to search for oxide superconductive structural features to realize screen module design'. A suitc of interactive programs has been written to run on this system, and it fits especially for the study of high temperature oxide superconductive structure-property relationship. Meanwhile it is also expected to be useful in the guidance of discovering new high temperature superconluctors.
A graphic svstem of superconductor models developed by the aid of a basie IBM-PC microcomputer is presented. This system has been designed to store informarion on structures and properties of superconductors and related compounds discovered so far, to display and plot three dimensional crystallographic structure and coordination polyhedron structure, to search for oxide superconductive structural features to realize screen module design'. A suitc of interactive programs has been written to run on this system, and it fits especially for the study of high temperature oxide superconductive structure-property relationship. Meanwhile it is also expected to be useful in the guidance of discovering new high temperature superconluctors.
1991, 13(3): 304-307.
Abstract:
A concept of gencral-node fauh diagnosis of switched capacitor (SC) networks is introduced. A simple, exact and effective algorithm is presented with emphasis on the advantages of using general-node concept. The diagnosability of SC networks is studied and the necessary conditions which make SC networks diagnosable are given.
A concept of gencral-node fauh diagnosis of switched capacitor (SC) networks is introduced. A simple, exact and effective algorithm is presented with emphasis on the advantages of using general-node concept. The diagnosability of SC networks is studied and the necessary conditions which make SC networks diagnosable are given.
1991, 13(3): 308-312.
Abstract:
The problems for calculating EM energy absorption by lossy dielectric scatterer irradiated by plane wave are discussed. The factors effecting the accuracy of com-putation are discussed. The calculated resuhs of EM energy absorption and its distribution in homogeneous and layered homogeneous lossy dielectric spheres are presented, and the com-parison of these results with analytical soturion is given. The calculation is carried out for dielectric cylinder on conducting ground as well, and the result is compared with the image theory. All the computations show that the finite-difference time-domain method can give satisfactory results.
The problems for calculating EM energy absorption by lossy dielectric scatterer irradiated by plane wave are discussed. The factors effecting the accuracy of com-putation are discussed. The calculated resuhs of EM energy absorption and its distribution in homogeneous and layered homogeneous lossy dielectric spheres are presented, and the com-parison of these results with analytical soturion is given. The calculation is carried out for dielectric cylinder on conducting ground as well, and the result is compared with the image theory. All the computations show that the finite-difference time-domain method can give satisfactory results.
1991, 13(3): 313-316.
Abstract:
The natural freqencies of a perfectly conducting sphere, a prolate spheroid (1:1:2) and a ellipsoid (1:2:3) are numerically solved by moment method with the magnetic field integral equation. The results reveal a splitting of natural freqencies when a sphere is deformed into a prolate spheroid or a ellipsoid.
The natural freqencies of a perfectly conducting sphere, a prolate spheroid (1:1:2) and a ellipsoid (1:2:3) are numerically solved by moment method with the magnetic field integral equation. The results reveal a splitting of natural freqencies when a sphere is deformed into a prolate spheroid or a ellipsoid.
1991, 13(3): 317-323.
Abstract:
The singular integral equation technique is used to determine the normal modes of propagation in asymmetrical bilateral finlines. Comparing with the published results, the present method is an accurate method and needs less coniputer time.
The singular integral equation technique is used to determine the normal modes of propagation in asymmetrical bilateral finlines. Comparing with the published results, the present method is an accurate method and needs less coniputer time.
1991, 13(3): 324-326.
Abstract:
The three-phase saturations of oil, gas and water system in cores are importam data for analyses and calculations of oil-field. According to the principle that microwave energy through a core is strongly absorbed by water content, while oil, gas and sandstone are relatively transparent, the microwave instrument for determining multi-phase saturations in cores with oil, gas and water is introduced. The attenuated signals proportional to water content are promptly processed, calculated and displayed by a signal processing unit. Results of measurements are displayed in digits in terms of percentage. The instrument is featured by its small size, simple structure and low cost. It has been used for measuring mufti-phase saturations of cylindrical cores with oil, gas and water. The measuring error is within土3.0%.
The three-phase saturations of oil, gas and water system in cores are importam data for analyses and calculations of oil-field. According to the principle that microwave energy through a core is strongly absorbed by water content, while oil, gas and sandstone are relatively transparent, the microwave instrument for determining multi-phase saturations in cores with oil, gas and water is introduced. The attenuated signals proportional to water content are promptly processed, calculated and displayed by a signal processing unit. Results of measurements are displayed in digits in terms of percentage. The instrument is featured by its small size, simple structure and low cost. It has been used for measuring mufti-phase saturations of cylindrical cores with oil, gas and water. The measuring error is within土3.0%.
1991, 13(3): 327-331.
Abstract:
Experimental investigation was carried out for the dynamic I-V characteris-tics of the bidirectional negative resistance transistor (BNRT) in the relaxation oscillation circuit. Some properties of the BNRT relaxation oscillation circuit were also analysed by means of the dynamic I-V characteristics. Experimental results agree with the computations. The direction for improving the device design is also pointed out in order to enhance the oscillation frequency.
Experimental investigation was carried out for the dynamic I-V characteris-tics of the bidirectional negative resistance transistor (BNRT) in the relaxation oscillation circuit. Some properties of the BNRT relaxation oscillation circuit were also analysed by means of the dynamic I-V characteristics. Experimental results agree with the computations. The direction for improving the device design is also pointed out in order to enhance the oscillation frequency.
1991, 13(3): 332-336.
Abstract:
The annealing behaviour and property of irradiation donor (ID) in NTDCZSi have been studied by using the Hall effect measurements and TEM. In addidon, the effects of a variety of neutron doses and impurity (oxygen and carbon) concentrations on the formation of ID are discussed. The phenomenon of Donor plateau is discovered for the first time. The experimental results show that ID creates about a 20 meV donor level in the forbidden band, which originates from the interface states of precipitated Si/SiO2.
The annealing behaviour and property of irradiation donor (ID) in NTDCZSi have been studied by using the Hall effect measurements and TEM. In addidon, the effects of a variety of neutron doses and impurity (oxygen and carbon) concentrations on the formation of ID are discussed. The phenomenon of Donor plateau is discovered for the first time. The experimental results show that ID creates about a 20 meV donor level in the forbidden band, which originates from the interface states of precipitated Si/SiO2.
