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1983 Vol. 5, No. 1
Display Method:
1983, 5(1): 1-5.
Abstract:
In this paper the study of the algorithm which has been done by the author for generating all the Hamiltonian cycles in a graph by a method of Wang algebra is continued. For simplifing the algorithm, a theorem of the constraint of degrees in the Wang s product is presented and for avoiding unnecessary repetitions in the algorithm some modified procedures are given.Finally, the application of the algorithm in layout design is discussed.
In this paper the study of the algorithm which has been done by the author for generating all the Hamiltonian cycles in a graph by a method of Wang algebra is continued. For simplifing the algorithm, a theorem of the constraint of degrees in the Wang s product is presented and for avoiding unnecessary repetitions in the algorithm some modified procedures are given.Finally, the application of the algorithm in layout design is discussed.
1983, 5(1): 6-15.
Abstract:
The concrete procedure using finite-element method to solve the eigenvalue problem of waveguides filled with inhomogeneous dielectrics is discussed. The relative formula and programs are given. For an example, the field structure analysis and calculation of the dispersion feature for dominant mode of the dielectric slab loaded rectangular waveguide have been completed. The rather consistent results with analytical solution are obtained and the reliability of the programs is verified.
The concrete procedure using finite-element method to solve the eigenvalue problem of waveguides filled with inhomogeneous dielectrics is discussed. The relative formula and programs are given. For an example, the field structure analysis and calculation of the dispersion feature for dominant mode of the dielectric slab loaded rectangular waveguide have been completed. The rather consistent results with analytical solution are obtained and the reliability of the programs is verified.
1983, 5(1): 16-23.
Abstract:
The doping behavior of sulphur in GaAs vapor phase epitaxy has been studied with the Ga-AsCl3-H2 system. The doping machamsm of sulphur has been discussed and submieron epilayers have been grown. It has been shown that the epitaxial layer obtained has high qualities and the reprodueibility of epitaxial growth is good. The typical electrical properties of epitaxial layer obtained are that the breakdown voltage is about 7-10V and the carrier concentration is about 1-2 1017/cm3 when epilayer thickness is less than 0.4m. For the single layer and the multilayer structures, the concentration drop in interface between the active layer and the buffer layer or substrate are sharp and the width of interface region is about 0.1m. The epilayers obtained have been used to fabricate the microwave devices such as varactor and far infrared detectors.
The doping behavior of sulphur in GaAs vapor phase epitaxy has been studied with the Ga-AsCl3-H2 system. The doping machamsm of sulphur has been discussed and submieron epilayers have been grown. It has been shown that the epitaxial layer obtained has high qualities and the reprodueibility of epitaxial growth is good. The typical electrical properties of epitaxial layer obtained are that the breakdown voltage is about 7-10V and the carrier concentration is about 1-2 1017/cm3 when epilayer thickness is less than 0.4m. For the single layer and the multilayer structures, the concentration drop in interface between the active layer and the buffer layer or substrate are sharp and the width of interface region is about 0.1m. The epilayers obtained have been used to fabricate the microwave devices such as varactor and far infrared detectors.
1983, 5(1): 24-31.
Abstract:
The dielectric tensor of the longitudinally magnetized relativistically gyrating and drifting electron beam is derived by means of the MHD equations. The coupling coefficients between various eigenmodes are then calculated by regarding the Gyro-TWA as a waveguide partially filled with an anisotropic medium. Analysis shows that only those modes with the same azimuthal index couple with each other. The results in this paper are of use for gyrotron devices operating in non-basic mode in estimating mode pureness.
The dielectric tensor of the longitudinally magnetized relativistically gyrating and drifting electron beam is derived by means of the MHD equations. The coupling coefficients between various eigenmodes are then calculated by regarding the Gyro-TWA as a waveguide partially filled with an anisotropic medium. Analysis shows that only those modes with the same azimuthal index couple with each other. The results in this paper are of use for gyrotron devices operating in non-basic mode in estimating mode pureness.
1983, 5(1): 32-37.
Abstract:
This paper describes a method of the design of the transition region of the electron beams from partially shielded cathode. This method is applicable to magnetic focusing structures of the axisymmetric high-density electron beam. Through synthetical choice of the parameters of a magnetic system and an electron gun, a optimum matching between the magnetic and the electron gun is obtained. So good results are given: a shielding coefficient Kc is higher than 0.8, a ripple ratio of the electron beams is less than 0.01.
This paper describes a method of the design of the transition region of the electron beams from partially shielded cathode. This method is applicable to magnetic focusing structures of the axisymmetric high-density electron beam. Through synthetical choice of the parameters of a magnetic system and an electron gun, a optimum matching between the magnetic and the electron gun is obtained. So good results are given: a shielding coefficient Kc is higher than 0.8, a ripple ratio of the electron beams is less than 0.01.
1983, 5(1): 38-48.
Abstract:
When T. V. pick-up tube is used under pulsed exposure, one will find the sensitivity of the tube descreases slightly and the quality of the picture degrades. These disadvantages can bo overcome by the use of delay readout and pulsing the cathode with suitable bias potentials.Eegarding to the complexity of the target surface due to partial overlapping of the electron scanning lines, we divide the scanning raster on the target into two parts, then analyse the signal current of these parts after pulsed exposure respectively. The obtained formulas can be used for calculating the signal current characteristics, some special case have been calculated, which give the useful informations for selecting the cathode bias potentials. Finally the paper shows how to select a T.V.pick-np tube for pulsed exposure application.
When T. V. pick-up tube is used under pulsed exposure, one will find the sensitivity of the tube descreases slightly and the quality of the picture degrades. These disadvantages can bo overcome by the use of delay readout and pulsing the cathode with suitable bias potentials.Eegarding to the complexity of the target surface due to partial overlapping of the electron scanning lines, we divide the scanning raster on the target into two parts, then analyse the signal current of these parts after pulsed exposure respectively. The obtained formulas can be used for calculating the signal current characteristics, some special case have been calculated, which give the useful informations for selecting the cathode bias potentials. Finally the paper shows how to select a T.V.pick-np tube for pulsed exposure application.
1983, 5(1): 49-53.
Abstract:
In this paper, the structure and the experimental results of a mirrorless FIR laser is described. A tunable TEA CO2 laser is used as its pumping source. Its output energy is about 1J at both 9R(22) and 9P(20) lines. Output energy of 0.5 mJ at =496m is obtained with CH3F molecular pumped by CO2 laser 9P(20) line; 1mJ =385m is obtained with D2O pumped by 9R(22) line. A thermopile and a Fanry-Perot interferometer are used to measure output energy and wavelength of FIR laser radiation respectively.
In this paper, the structure and the experimental results of a mirrorless FIR laser is described. A tunable TEA CO2 laser is used as its pumping source. Its output energy is about 1J at both 9R(22) and 9P(20) lines. Output energy of 0.5 mJ at =496m is obtained with CH3F molecular pumped by CO2 laser 9P(20) line; 1mJ =385m is obtained with D2O pumped by 9R(22) line. A thermopile and a Fanry-Perot interferometer are used to measure output energy and wavelength of FIR laser radiation respectively.
1983, 5(1): 54-57.
Abstract:
A method for obtaining pure oxygen by heating silver tube and its device are described. The mass-spectrums of some gases have been measured, and its partial pressures have been calculated. Corresponding oxygen pressures have been obtained when silver tube was heated to different temperatures.
A method for obtaining pure oxygen by heating silver tube and its device are described. The mass-spectrums of some gases have been measured, and its partial pressures have been calculated. Corresponding oxygen pressures have been obtained when silver tube was heated to different temperatures.
INFLUENCE OF BAKE-OUT AND Cs VAPOUR ON SOME PROPERTIES OF CHANNEL ELECTRON MULTIPLIER(CEM) IN VACUUM
1983, 5(1): 58-63.
Abstract:
In this paper, the changes of the resistance and the electron gain of the CEM after bake-out at different temperatures and treatment with Cs are examined. It is found, that the transition temperature of the resistance from reversible change into irreversible is 250℃ or higher. A method of determining the optimum gain of the CEM during heating by means of measuring the resistance changes is proposed. The damaging action of Cs to CEM is investigated and proper protecting means is proposed. It is shown, that the method of convering two ends of the CEM with nickel caps is an effective one for preventing the CEM from being damaged by Cs during Cs treatment.
In this paper, the changes of the resistance and the electron gain of the CEM after bake-out at different temperatures and treatment with Cs are examined. It is found, that the transition temperature of the resistance from reversible change into irreversible is 250℃ or higher. A method of determining the optimum gain of the CEM during heating by means of measuring the resistance changes is proposed. The damaging action of Cs to CEM is investigated and proper protecting means is proposed. It is shown, that the method of convering two ends of the CEM with nickel caps is an effective one for preventing the CEM from being damaged by Cs during Cs treatment.
1983, 5(1): 64-65.
Abstract:
A new type of dispenser cathode which is fabricated by compressing and sintering a mixture of powdered tungsten carbide, lanthanum and platinum has been developed. It has good properties: high emission current density, good ability of resisting the poisoning of gas, exposed to atmosphere repeatedly without deterioration and long life.The cathode can particularly withstand the poisoning of oil vapour, so that they have been successfully used in sealed oil film light value tube.
A new type of dispenser cathode which is fabricated by compressing and sintering a mixture of powdered tungsten carbide, lanthanum and platinum has been developed. It has good properties: high emission current density, good ability of resisting the poisoning of gas, exposed to atmosphere repeatedly without deterioration and long life.The cathode can particularly withstand the poisoning of oil vapour, so that they have been successfully used in sealed oil film light value tube.
1983, 5(1): 66-66.
Abstract:
For special microwave devices and precision instruments, the flux density of the permanent magnets has to be a constant over a wide temperature range. It means that a kind of permanent magnetic material with low reversible temperature coefficient is needed. Thus, the permanent magnetic material containing Gd and Er is fabricated. The material is prepared by liquid phase-sintering technique. The effects of composition, ball milling time, sintering temperature and heat treatment on the magnetic properties of the materialarestudied.
For special microwave devices and precision instruments, the flux density of the permanent magnets has to be a constant over a wide temperature range. It means that a kind of permanent magnetic material with low reversible temperature coefficient is needed. Thus, the permanent magnetic material containing Gd and Er is fabricated. The material is prepared by liquid phase-sintering technique. The effects of composition, ball milling time, sintering temperature and heat treatment on the magnetic properties of the materialarestudied.
1983, 5(1): 67-68.
Abstract:
This paper presents a new technology of surface treatment of the grid made of molybdenum plate by electric spark machining. Procedures of the new technology are as follows: a. Boiling in 10% NaOH solution; b. Ultrasonic treating with emery + HCl solution; c. Ultrasonic treating with emery+Fe+++ Sal+H2O+small inhibitor; d. Electro-polishing with H3PO4-H2SO4-C3H5(OH)3-H2O solution.
This paper presents a new technology of surface treatment of the grid made of molybdenum plate by electric spark machining. Procedures of the new technology are as follows: a. Boiling in 10% NaOH solution; b. Ultrasonic treating with emery + HCl solution; c. Ultrasonic treating with emery+Fe+++ Sal+H2O+small inhibitor; d. Electro-polishing with H3PO4-H2SO4-C3H5(OH)3-H2O solution.
