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1985 Vol. 7, No. 2
Display Method:
1985, 7(2): 81-91.
Abstract:
Two topological expressions (A) and (B) and their proofs for general k-order cofaetor of the indefinite-admittance matrix of an aetive networks are presented. The expression (A) is the unification and extension of Chen s topological expressions (1965, 1976) for 1, 2, 3-order and special k-order cofactors. The expression (B) shows thatthere is another topological analysis method for active networkspositive root di-rected k-tree method.
Two topological expressions (A) and (B) and their proofs for general k-order cofaetor of the indefinite-admittance matrix of an aetive networks are presented. The expression (A) is the unification and extension of Chen s topological expressions (1965, 1976) for 1, 2, 3-order and special k-order cofactors. The expression (B) shows thatthere is another topological analysis method for active networkspositive root di-rected k-tree method.
1985, 7(2): 92-97.
Abstract:
In order to study the approach of realizing a high level system on circuits design, an experimental modei system named Bloek is proposed and described in this paper. The Block system is able to work out automatically the diagram of an analogous eireuit only according to the given specifications of the input and output signak of the eireuit. Ordinarily, this job must be under taken by the designer not by the machine.
In order to study the approach of realizing a high level system on circuits design, an experimental modei system named Bloek is proposed and described in this paper. The Block system is able to work out automatically the diagram of an analogous eireuit only according to the given specifications of the input and output signak of the eireuit. Ordinarily, this job must be under taken by the designer not by the machine.
1985, 7(2): 98-107.
Abstract:
Based on the cavity modei theory, a set of simple formulas and graphs for calculating both the radiation pattern bandwidth and the impedance bandwidth of a rectangular microstrip antenna are presented with experimental verification. Three kinds of approaches to broaden the bandwidth and their potentiality are reviewed and discussed. A simple broadband teehnique by means of combination of stub-matching and increasing the antenna thickness is developed. A test element with the thickness of 0.05 wavelength has been matched by using two stubs, while the input VSWR is measured to be less than 2:1 over a 13% bandwidth.
Based on the cavity modei theory, a set of simple formulas and graphs for calculating both the radiation pattern bandwidth and the impedance bandwidth of a rectangular microstrip antenna are presented with experimental verification. Three kinds of approaches to broaden the bandwidth and their potentiality are reviewed and discussed. A simple broadband teehnique by means of combination of stub-matching and increasing the antenna thickness is developed. A test element with the thickness of 0.05 wavelength has been matched by using two stubs, while the input VSWR is measured to be less than 2:1 over a 13% bandwidth.
1985, 7(2): 108-113.
Abstract:
Transient photoresponse spectra in -Si: H film with sandwich structure are measured. It is found that at the starting part of these curves anomalous pulse appears under either a small forward bias or a small reverse one. The pulse amplitude decreases when the light wavelength increases. Analysis of the transient response spectra without bias, showed that this anomalous non-transport component originates from the barrier region. Its rise or deeay characteristic is determined by space-charge-limited photocurents. With the relation between its amplitude and optical absorption, we developed a method to obtain optical band gap of the films studied.
Transient photoresponse spectra in -Si: H film with sandwich structure are measured. It is found that at the starting part of these curves anomalous pulse appears under either a small forward bias or a small reverse one. The pulse amplitude decreases when the light wavelength increases. Analysis of the transient response spectra without bias, showed that this anomalous non-transport component originates from the barrier region. Its rise or deeay characteristic is determined by space-charge-limited photocurents. With the relation between its amplitude and optical absorption, we developed a method to obtain optical band gap of the films studied.
1985, 7(2): 114-120.
Abstract:
A study of the magnetic domain structure of (Sm, Gd, Er)Co5 magnet by magneto-optical Kerr effect is presented. Two samples with different intrinsic eoercive forces are compared one another in their variations in the domain structure during different stages of magnetization and demagnetization.The results indicate that the coercivity of the magnet made of this kind of magnetic material is mainly controlled by nucleation mechanism. Hence, to improve its magnetic properties, the reversal magnetized nucleation must be restrained. In practise, it can be done by keeping the composition of magnetic materials accurate and homogeneous, increasing the density of the magnet, decreasing the content of impurity and hole, etc.
A study of the magnetic domain structure of (Sm, Gd, Er)Co5 magnet by magneto-optical Kerr effect is presented. Two samples with different intrinsic eoercive forces are compared one another in their variations in the domain structure during different stages of magnetization and demagnetization.The results indicate that the coercivity of the magnet made of this kind of magnetic material is mainly controlled by nucleation mechanism. Hence, to improve its magnetic properties, the reversal magnetized nucleation must be restrained. In practise, it can be done by keeping the composition of magnetic materials accurate and homogeneous, increasing the density of the magnet, decreasing the content of impurity and hole, etc.
1985, 7(2): 121-126.
Abstract:
In this paper the general expression of the filling factor of spherical storage bulb for the hydrogen maser is derived. The filling factors for the cases where sizes of cavity and spherical storage bulb chosen arbitrarily were calculated and the relationship between the filling factor and the normalized radius of spherical storage bulb is presented.
In this paper the general expression of the filling factor of spherical storage bulb for the hydrogen maser is derived. The filling factors for the cases where sizes of cavity and spherical storage bulb chosen arbitrarily were calculated and the relationship between the filling factor and the normalized radius of spherical storage bulb is presented.
1985, 7(2): 127-135.
Abstract:
This paper describes the computation methods of the deflection field of the deflection yoke with wedge profile and the electrostatic deflector with planar electrodes. The wedge yokes can be combined into various magnetic deflectors, which would offer a variety of choices for more effectively reducing the deflection aberrations by properly adjusting the deflection. field distribution. An advantage of the planar electrostatic deflector is its simplicity in structure. Thus it is probable that a deflector array for the multiple electron beam systems can be composed by the use of this kind of deflector. Based on the described methods in this paper, two practical computation programs have been worked out and, as examples, the field distributions of some typical deflectors have been computed.
This paper describes the computation methods of the deflection field of the deflection yoke with wedge profile and the electrostatic deflector with planar electrodes. The wedge yokes can be combined into various magnetic deflectors, which would offer a variety of choices for more effectively reducing the deflection aberrations by properly adjusting the deflection. field distribution. An advantage of the planar electrostatic deflector is its simplicity in structure. Thus it is probable that a deflector array for the multiple electron beam systems can be composed by the use of this kind of deflector. Based on the described methods in this paper, two practical computation programs have been worked out and, as examples, the field distributions of some typical deflectors have been computed.
1985, 7(2): 136-143.
Abstract:
Because of the nonconservation of energy in Rowe s modei for large signal interaction in TWT, Rowe s modei produces considerable error in TWT design, especially for a velocity-tapered one, A modified model which is based on energy conservation is suggested to improve the accuracy of the design of TWT. By the new model, when the loss and space charge in TWT are neglected, the energy received by the circuit is exactly equal to that given by the electron beam. And all the results obtained with the new model a re in better agreement with the actual cases then those obtained with Rowe's model.
Because of the nonconservation of energy in Rowe s modei for large signal interaction in TWT, Rowe s modei produces considerable error in TWT design, especially for a velocity-tapered one, A modified model which is based on energy conservation is suggested to improve the accuracy of the design of TWT. By the new model, when the loss and space charge in TWT are neglected, the energy received by the circuit is exactly equal to that given by the electron beam. And all the results obtained with the new model a re in better agreement with the actual cases then those obtained with Rowe's model.
1985, 7(2): 144-151.
Abstract:
This paper continues the study in autherls former paper (1982). According to the theorem for generating 1-factors by star product described in former paper, we consider a class of special graphs at first, for which the relations between star product and permutation are established and then the relations are extened to the general case. Finally, we give an algorithm to find the 1-factors of a Coates graph.
This paper continues the study in autherls former paper (1982). According to the theorem for generating 1-factors by star product described in former paper, we consider a class of special graphs at first, for which the relations between star product and permutation are established and then the relations are extened to the general case. Finally, we give an algorithm to find the 1-factors of a Coates graph.
1985, 7(2): 152-157.
Abstract:
The stlspended microstrip line is used widely in the microwave integrated circuits due to its low loss property and large size. The frequeney eharacteristics of suspended microstrip lines are analyzed by using the spectral domain immittance approach. The characteristie impedance and relative guided wavelength curves are given for different dielectric materials.
The stlspended microstrip line is used widely in the microwave integrated circuits due to its low loss property and large size. The frequeney eharacteristics of suspended microstrip lines are analyzed by using the spectral domain immittance approach. The characteristie impedance and relative guided wavelength curves are given for different dielectric materials.
1985, 7(2): 158-160.
Abstract:
This paper describes a simple design method of a vertical polarized antenna operated in the X-Band. This antenna consists of longitudinal shunt slotted array at the broad side of rectangular waveguide and metallic horned plates.A real size model was fabricated. The eomputed results are in agreement with measured ones approximately. Although this method is preliminary, it has practical value in antenna design.
This paper describes a simple design method of a vertical polarized antenna operated in the X-Band. This antenna consists of longitudinal shunt slotted array at the broad side of rectangular waveguide and metallic horned plates.A real size model was fabricated. The eomputed results are in agreement with measured ones approximately. Although this method is preliminary, it has practical value in antenna design.
