In deriving the diffusion equation, diffusion tensor and dispersion relation in respect of the inhomogeneity in plasma, the Misquich-Balescu's theory on turbulence in uniform plasma can be generalized to the case of non-uniform plasma. It is indicated that the method given by Pelletier et al. in considering the plasma turbulence as a Markov process is now inadequate to describe the turbulence in non-uniform Plasma.
In deriving the diffusion equation, diffusion tensor and dispersion relation in respect of the inhomogeneity in plasma, the Misquich-Balescu's theory on turbulence in uniform plasma can be generalized to the case of non-uniform plasma. It is indicated that the method given by Pelletier et al. in considering the plasma turbulence as a Markov process is now inadequate to describe the turbulence in non-uniform Plasma.
Upon the basis of the theory in article I, we have derived an explicit expression of resonant diffusion tensor in terms of the steady-state turbulent spectrum Sk0(0) and compared our result with that given by Birmingham et al. We also compare the dispersion relation derived in I with the corresponding result derived by Birmingham et al.
Upon the basis of the theory in article I, we have derived an explicit expression of resonant diffusion tensor in terms of the steady-state turbulent spectrum Sk0(0) and compared our result with that given by Birmingham et al. We also compare the dispersion relation derived in I with the corresponding result derived by Birmingham et al.
In this paper a method is presented for solving the equilibrium problem with axisymmetry for arbitraryly given plasma configurations. First, the boundary value problem of equilibrium equation is solved by finite element method for a given plasma boundary and current distribution. Then, based on virtual-casing principle, the virtual-casing current which produces the maintaining magnetic field requisite for the equilibrium is obtained by using solution of the equilibrium equation. The field of virtual-casing current, i.e. the maintaining field inside plasma is calculated. The current distribution of maintaining field on a certain contour outside the plasma is found by means of solving the integral equation. The main difficulty confronted in solving the integral equation problem is that one has to deal with an incorrectly posed problem. We have solved the incorrectly posed Fredholm integral equation of first kind, using a method of singular value decomposition. This method is simple and effective in solving such an equilibrium problem.We have considered seven types of plasma configuration including circular, elliptic, doublet, race-track, D-, back D- and banana shapes and three kinds of plasma current distribution including quasi-uniform, diffusion-type and skin-type distribution. Three type of current distribution for maintaining field are obtained in a given circular-, elliptic- and -shapes. For the models as mentioned above, the current distribution of maintaining field and the field itself are given. The total currents of maintaining field and total plasma currents are compared with each other. Some influences of the maintaining fields on stability is discussed.
In this paper a method is presented for solving the equilibrium problem with axisymmetry for arbitraryly given plasma configurations. First, the boundary value problem of equilibrium equation is solved by finite element method for a given plasma boundary and current distribution. Then, based on virtual-casing principle, the virtual-casing current which produces the maintaining magnetic field requisite for the equilibrium is obtained by using solution of the equilibrium equation. The field of virtual-casing current, i.e. the maintaining field inside plasma is calculated. The current distribution of maintaining field on a certain contour outside the plasma is found by means of solving the integral equation. The main difficulty confronted in solving the integral equation problem is that one has to deal with an incorrectly posed problem. We have solved the incorrectly posed Fredholm integral equation of first kind, using a method of singular value decomposition. This method is simple and effective in solving such an equilibrium problem.We have considered seven types of plasma configuration including circular, elliptic, doublet, race-track, D-, back D- and banana shapes and three kinds of plasma current distribution including quasi-uniform, diffusion-type and skin-type distribution. Three type of current distribution for maintaining field are obtained in a given circular-, elliptic- and -shapes. For the models as mentioned above, the current distribution of maintaining field and the field itself are given. The total currents of maintaining field and total plasma currents are compared with each other. Some influences of the maintaining fields on stability is discussed.
After a comprehensive consideration on the factors of coil, circuit, and power, this article gives, for the first time, a general theory of designing a standard capacitor discharge pulse magnet (winding coil, Bitter coil, or single turn coil).According to the theory, the optimum contruction parameters of the magnet and the parameters of the power (i0, F(α, β), a2, b, L, C, N, l, S, (or d), B, and Imax) can be caculated if only the figures of B0, 2a, 1/2 T, λ,σ, and v are given.This article also makes a physical study on the optimum construction of magnet.
After a comprehensive consideration on the factors of coil, circuit, and power, this article gives, for the first time, a general theory of designing a standard capacitor discharge pulse magnet (winding coil, Bitter coil, or single turn coil).According to the theory, the optimum contruction parameters of the magnet and the parameters of the power (i0, F(α, β), a2, b, L, C, N, l, S, (or d), B, and Imax) can be caculated if only the figures of B0, 2a, 1/2 T, λ,σ, and v are given.This article also makes a physical study on the optimum construction of magnet.
A grating coupler with a period of 0.56 μm has been built on the glass substrate by duplicating technique from a master grating. It has been experimentally observed that laser beam can be coupled into the waveguide film from above cair, as well as from below (substrate). The mode excited in the waveguide can be varied by varying the angle of incidence of laser beam, and light wave of different diffraction order can also be coupled into guide wave mode. An input coupling efficiency of 66.0±0.5% has been achieved experimentally.
A grating coupler with a period of 0.56 μm has been built on the glass substrate by duplicating technique from a master grating. It has been experimentally observed that laser beam can be coupled into the waveguide film from above cair, as well as from below (substrate). The mode excited in the waveguide can be varied by varying the angle of incidence of laser beam, and light wave of different diffraction order can also be coupled into guide wave mode. An input coupling efficiency of 66.0±0.5% has been achieved experimentally.
The diffusing reflective surface illuminated by coherent light generates random speckle in space. The movement of the surface relative to the source causes corresponding movement of the speckle. When a moving speckle is tracked, it implies that the intensity of speckle is constant yet the phase of the speckle is allowed to vary. From the Fresnel-Kirchhoff Integration, three fundamental rules of speckle movement are derived, i.e. Equations (3), (4) and (5) in this paper. The first and second equations are similar to those of grating. The third equation is similar to the lens law. From these rules, a speckle movement formula, relating to the surface movement, is derived as equation (18), in which the coordinate system adopted is fixed in space. It is an equation in matrix form, which denotes six types of surface movements, i. e. three rotations and three translations. The experimental results are in good agreement with this formula. These fundamental rules can be used to analyse general space diffractive patterns.
The diffusing reflective surface illuminated by coherent light generates random speckle in space. The movement of the surface relative to the source causes corresponding movement of the speckle. When a moving speckle is tracked, it implies that the intensity of speckle is constant yet the phase of the speckle is allowed to vary. From the Fresnel-Kirchhoff Integration, three fundamental rules of speckle movement are derived, i.e. Equations (3), (4) and (5) in this paper. The first and second equations are similar to those of grating. The third equation is similar to the lens law. From these rules, a speckle movement formula, relating to the surface movement, is derived as equation (18), in which the coordinate system adopted is fixed in space. It is an equation in matrix form, which denotes six types of surface movements, i. e. three rotations and three translations. The experimental results are in good agreement with this formula. These fundamental rules can be used to analyse general space diffractive patterns.
Starting from the basic formulism of nuclear reaction kinematics, the general expressions of the total yield and the energy spectra of the secondary particles of thermonuclear reactions in plasma with the Maxwellian velocity distribution of ions have been derived. The possibility of using the neutron and charged particles as a tool of plasma diagnostic is also discussed.
Starting from the basic formulism of nuclear reaction kinematics, the general expressions of the total yield and the energy spectra of the secondary particles of thermonuclear reactions in plasma with the Maxwellian velocity distribution of ions have been derived. The possibility of using the neutron and charged particles as a tool of plasma diagnostic is also discussed.
In this paper, we have proposed a simple method to determine what charges the carriers in ionic conductor possess by analysing the relation of voltages between middle point of the sample and its two terminal surface electrodes. By using this method and considering that α-LiIO3 single crystal can be regarded as a quasi 1-dimension conductor, it has been found that there are two kinds of carriers in α-LiIO3 single crystal. One of them is the interstitial Li ion which hops among the intersites in a zigzag channel along c-axis. The other is the Li vacancy which exchanges positions with Li ions at lattice sites also along c-axis. We have measured the electrica conduction properties from -100℃ up to room temperature. The results are analogous to those obtained above room temperature.
In this paper, we have proposed a simple method to determine what charges the carriers in ionic conductor possess by analysing the relation of voltages between middle point of the sample and its two terminal surface electrodes. By using this method and considering that α-LiIO3 single crystal can be regarded as a quasi 1-dimension conductor, it has been found that there are two kinds of carriers in α-LiIO3 single crystal. One of them is the interstitial Li ion which hops among the intersites in a zigzag channel along c-axis. The other is the Li vacancy which exchanges positions with Li ions at lattice sites also along c-axis. We have measured the electrica conduction properties from -100℃ up to room temperature. The results are analogous to those obtained above room temperature.
The impurity-striations and the dislocation loop series produced from the volume indentation by these impurity-striations in the float-zone grown silicon single crystals have been studied by means of chemical etching method. The experimental results have shown that the impurity-striations are oriented in the direction (110) of planes {111} in silicon, the length of the impurity-strialions is about 5-230μm, the dimensions on cross-section are about 2-3 pun. The geometrical structure of the dislocation loop series produced by volume indentation of the impurity-striation has been studied. The form and size of a single dislocation loop depend on the form and size of the impurity-striation. The dislocation networks resulting from the cross-superposition of the dislocation loop series and reactions between these dislocation loops have been observed and analyzed.
The impurity-striations and the dislocation loop series produced from the volume indentation by these impurity-striations in the float-zone grown silicon single crystals have been studied by means of chemical etching method. The experimental results have shown that the impurity-striations are oriented in the direction (110) of planes {111} in silicon, the length of the impurity-strialions is about 5-230μm, the dimensions on cross-section are about 2-3 pun. The geometrical structure of the dislocation loop series produced by volume indentation of the impurity-striation has been studied. The form and size of a single dislocation loop depend on the form and size of the impurity-striation. The dislocation networks resulting from the cross-superposition of the dislocation loop series and reactions between these dislocation loops have been observed and analyzed.
Two low frequency internal friction peaks have been observed at 243 K and 333 K respectively in Al-0.03 at% Mg alloy during the process of temperature going up after the specimen was stretched in situ with a tensile strain of 0.5% at 208 K. Such two peaks appeared also at the same temperatures when the measurement was made in the subsequent cooling from 353 K. The dependence of internal friction on the amplitude was determined and the amplitude internal friction peaks were observed in the temperature range of the peaks. The relationship between these two kinds of peaks was analysed and the effective activation energies of the temperature internal friction peaks were found to be about 0.32 eV for the 243 K peak and 0.22 eV for the 333 K peak. It was suggested that the two peaks at 333 K and 243 K may be respectively associated with the dragging of the solute atoms and the 'Mg atom-vacancy' pairs, which may be produced through the sidewise motion of the kinks on the dislocations formed during the low temperature cold working.
Two low frequency internal friction peaks have been observed at 243 K and 333 K respectively in Al-0.03 at% Mg alloy during the process of temperature going up after the specimen was stretched in situ with a tensile strain of 0.5% at 208 K. Such two peaks appeared also at the same temperatures when the measurement was made in the subsequent cooling from 353 K. The dependence of internal friction on the amplitude was determined and the amplitude internal friction peaks were observed in the temperature range of the peaks. The relationship between these two kinds of peaks was analysed and the effective activation energies of the temperature internal friction peaks were found to be about 0.32 eV for the 243 K peak and 0.22 eV for the 333 K peak. It was suggested that the two peaks at 333 K and 243 K may be respectively associated with the dragging of the solute atoms and the 'Mg atom-vacancy' pairs, which may be produced through the sidewise motion of the kinks on the dislocations formed during the low temperature cold working.
Based on the Eliashberg equation, a formula for calculating the convergence radius Λ-1 of the Tc series solution is proved. Practically, it is identical with that which was conjectured in a previous paper by one of the authors and his co-workers. Therefore, the method for calculating Λ suggested by them is justified.
Based on the Eliashberg equation, a formula for calculating the convergence radius Λ-1 of the Tc series solution is proved. Practically, it is identical with that which was conjectured in a previous paper by one of the authors and his co-workers. Therefore, the method for calculating Λ suggested by them is justified.
The methods of configurational average of ensemble on a homogeneously random binary system is extended to treat a conditionally random binary system, where the concentration of one species c(r) is not a constant but modulated in a certain way. A restricted ensemble is chosen to describe such a system, the corresponding generalized CPA equation is derived. If we separate c(r) into c and δc(r), a decomposition scheme is introduced to average the uniform part c and deviation part dc successively. For a sinusoidal modulation, the averaged single-particle Green's function and its self-energy are calculated formally to the second order in δc/c. In the virtual crystal limit, the band splitting character of a superlattice is recovered.
The methods of configurational average of ensemble on a homogeneously random binary system is extended to treat a conditionally random binary system, where the concentration of one species c(r) is not a constant but modulated in a certain way. A restricted ensemble is chosen to describe such a system, the corresponding generalized CPA equation is derived. If we separate c(r) into c and δc(r), a decomposition scheme is introduced to average the uniform part c and deviation part dc successively. For a sinusoidal modulation, the averaged single-particle Green's function and its self-energy are calculated formally to the second order in δc/c. In the virtual crystal limit, the band splitting character of a superlattice is recovered.
In this article, we have studied the response and the cross section o:E a torsional pendulum to gravitational waves, and discussed some related problems. This article shows that the pendulum can be taken as a mechanical resonance antenna for detecting low frequency gravitational waves.
In this article, we have studied the response and the cross section o:E a torsional pendulum to gravitational waves, and discussed some related problems. This article shows that the pendulum can be taken as a mechanical resonance antenna for detecting low frequency gravitational waves.
The phase transition and super-paramagnetism in sintering process of Sr ferrite powders prepared by chemical co-precipitation were examined by Mbssbauer spectroscopy. The influence of particle size on phase transition was analyzed. The parameters of 5 hyperfine sub-spectra of Sr ferrite were determined.
The phase transition and super-paramagnetism in sintering process of Sr ferrite powders prepared by chemical co-precipitation were examined by Mbssbauer spectroscopy. The influence of particle size on phase transition was analyzed. The parameters of 5 hyperfine sub-spectra of Sr ferrite were determined.
The ellipsometric method has been developed to investigate the radiation damage and annealing effect in As ion implanted silicon. For 1×1016 cm-2, 150 keV As ion implantation, the refractive index-depth profile exhibits a plateau form, indicating the existence of an amorphous layer. The annealing temperature used to remove amorphous layer must be about 700℃ or higher. The experimental results show that the ellipso-meter is one of the useful tools for radiation damage determinations.
The ellipsometric method has been developed to investigate the radiation damage and annealing effect in As ion implanted silicon. For 1×1016 cm-2, 150 keV As ion implantation, the refractive index-depth profile exhibits a plateau form, indicating the existence of an amorphous layer. The annealing temperature used to remove amorphous layer must be about 700℃ or higher. The experimental results show that the ellipso-meter is one of the useful tools for radiation damage determinations.
The diffraction geometries of asymmetric Johann crystal monochromator and asymmetric logarithmic-spiral crystal monochromator are analysed in detail. The formulas for calculating the distance L1 between focus of X-ray source and monochromator, the dispersion width b1, b2 of cross section of source and focusing line are given. According to the result of theoretical analysis, the adjustable elastically bent quartz crystal monochromator which is the approximate asymmetric Johann type is used in the construction of X-ray focusing camera.
The diffraction geometries of asymmetric Johann crystal monochromator and asymmetric logarithmic-spiral crystal monochromator are analysed in detail. The formulas for calculating the distance L1 between focus of X-ray source and monochromator, the dispersion width b1, b2 of cross section of source and focusing line are given. According to the result of theoretical analysis, the adjustable elastically bent quartz crystal monochromator which is the approximate asymmetric Johann type is used in the construction of X-ray focusing camera.
A new phenomenon about {111} planar particles blocking dip in Si has been found. Between the {111} planes in single crystal Si there are two interplanar spacings, d(111)(a) and d(111)(b), but there is only one interplanar spacing d(110) between Si{110} planes, so that their blocking dips would be different. We have observed this difference from the experiments of a particle and proton blocking effect in single crystal Si. We have also estimated the 2ψ1/2 angles from planar particles blocking dips with d(111)(a), d(111)(b) and d(110) in Si respectively. According to the author's knowledge, up to the present, this phenomenon has not yet been discovered at home and abroad. This new phenomenon will promote the study of complex crystals using the blocking and channeling effects.
A new phenomenon about {111} planar particles blocking dip in Si has been found. Between the {111} planes in single crystal Si there are two interplanar spacings, d(111)(a) and d(111)(b), but there is only one interplanar spacing d(110) between Si{110} planes, so that their blocking dips would be different. We have observed this difference from the experiments of a particle and proton blocking effect in single crystal Si. We have also estimated the 2ψ1/2 angles from planar particles blocking dips with d(111)(a), d(111)(b) and d(110) in Si respectively. According to the author's knowledge, up to the present, this phenomenon has not yet been discovered at home and abroad. This new phenomenon will promote the study of complex crystals using the blocking and channeling effects.
The microstructure of the single core and multifilamentary Nb/Nb3Sn composite materials has been observed using a 1000 kV HVEM. Two types of moire patterns, formed by overlapping Nb3Sn/Nb3Sn and Nb/Nb3Sn crystals respectively, have been found.
The microstructure of the single core and multifilamentary Nb/Nb3Sn composite materials has been observed using a 1000 kV HVEM. Two types of moire patterns, formed by overlapping Nb3Sn/Nb3Sn and Nb/Nb3Sn crystals respectively, have been found.
The Kirchhoff-Fresnel integral equation is transformed into Fourier space and the analytical eigenfunctions, eigenvalus, resonance conditions and far field distributions are obtained. The form of eigenfunctions obtained in the Fourier space are very simple, this result might be used as a convenient start point for further investigation of the unstable optical resonator.
The Kirchhoff-Fresnel integral equation is transformed into Fourier space and the analytical eigenfunctions, eigenvalus, resonance conditions and far field distributions are obtained. The form of eigenfunctions obtained in the Fourier space are very simple, this result might be used as a convenient start point for further investigation of the unstable optical resonator.