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Vol. 21, No. 1 (1965)

1965-01-05
CONTENT
THE B2 GROUP AND THE STRONG INTERACTION OF ELEMENTARY PARTICLES
GUAN HONG
1965, 21 (1): 1-11. doi: 10.7498/aps.21.1
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The reduction coefficients appearing in the decomposition of direct products of irreducible representations 4×4, 4×5, 4×10, 5×5 of the group B2 are calculated. Some examples of their application to the strong interaction symmetry of elementary particles are given: the relations between various scattering cross sections and the mass relations for low-dimensional irreducible representations are derived, and the assignment and decay modes of resonant states and the R-inverse invariance are discussed.
ON A VARIATIONAL METHOD AND THE RP-HRP APPROXIMATION
WU SHI-SHU
1965, 21 (1): 12-18. doi: 10.7498/aps.21.12
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It is shown that the RP-HRP (random phase and higher random phase) approximation may be derived by a variational method. The reason why the secular equation of the RP-HRP approximation is nonhermitian is then made clear and a procedure which can lead it to be hermitian is suggested. It is further pointed out that the variation principle may also serve as a method to determine the average occupation numbers nr=0|fr-1∑μξrμ+ξrμ|Ψ0>.
ON THE RESONANCE LINE WIDTH OF FERRIMAGNETICS CAUSED BY IMPURITY SCATTERING
HSU DSEN-I
1965, 21 (1): 19-36. doi: 10.7498/aps.21.19
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In this work, it has been found for an ellipsoid of a ferrimagnetic with two equivalent sublattices of unlike ions that the frequency spectrum of spin waves consists of two branches and in each of them the dependence of frequency on the wave vector is similar to the spin wave spectrum of a ferromagnetic ellipsoid. Based on this spectrum and the scattering mechanism of spin waves due to the fluctuation of exchange interactions, calculations have been made for the line width of the uniform resonance and that of the exchange resonance. For the former the conclusions obtained by using the model of an equivalent ferromagnetic are still valid; i.e. nonmagnetic impurity ions and the impurity ions whose spins equal to that of the matrix ion on the same sublattice have no effect on the line width of uniform resonance. However, the impurity ions of both these kinds should give rise to the line width of exchange resonance. There exists a large difference in the line width of uniform resonance estimated for various ferrites by making use of our simplified model of ferrimagnetism. Quite probably the fluctuation of the exchange interactions is the main cause of the line width of uniform resonance in a number of ferrites. The exchange resonance line width caused by this mechanism are estimated for ferrites generally of the order of several tens in the oersted.
INTERACTION BETWEEN FREE ELECTRONS AND INTENSIVE LIGHT BEAM——MULTI-PHOTON PROCRSSES OF THE CARRIERS IN SEMICONDUCTORS
HO YU-PING
1965, 21 (1): 37-50. doi: 10.7498/aps.21.37
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In the present article the interaction between carriers in semi-conductors and a laser beam has been discussed. The influence of intensive light on the intraband motion of an electron was treated, with the conclusion reached that the states of the electron withinone band can still be characterized by a set of quantum numbers-the quasi-momentump and that the wave function contains a factor describing the forced motion in the extremely strong electromagnetic field. The interband transition and other intraband scattering processes were then treated as perturbations. During the transition process, the forced motion changes with the absorption or emission of a number of photons.Following the above discussions, the absorption constants for multi-photon processes of free carrier absorption (with the partipation of the electron-phonon coupling) and the direct transition from valent band to conduction band were calculated. It was estimated that in some materials the two-photon process of the type discussed can be observed easily, especially the direct absorption of two photons in Ge. It was pointed out that using the laser light (the frequency of which is nearly equal to the forbidden energy gap), the absorption lines of the exciton may be shifted to the infrared region, so that the resolving power may be improved. As an example, the case of CdSe was discussed.
THE DECOMPOSITION OF DIRECT PRODUCTS OF IRREDUCIBLE REPRESENTATIONS OF SU3
SUN HUNG-CHOU, HAN QI-ZHI
1965, 21 (1): 56-66. doi: 10.7498/aps.21.56
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Using the familiar concepts of rotation group, we obtain the irreducible unitary representations and the reduction coefficients of the group SU3. (These coefficients may be called the generalized Clebsch-Gordan coefficients.) This method is easier than those given by other authors.
THE LOW ENERGY KAON-PION SCATTERING
CHOU LON-SHANG, CHEN TING-GIN
1965, 21 (1): 67-74. doi: 10.7498/aps.21.67
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In this paper the method suggested by L. A. P. Balazs for solving the problem of the low energy pion-pion scattering is applied to the kaon-pion scattering process. It isfound that the position of the K* resonance is (SR)1/2=854MeV, the half-width 1/2Г11/2 = 126 MeV, and the phenomenological constant of the amplitude of the process π + π→ K + K ξ = 0.3 μ-2. The position of the K* resonance is in good agreement with experiment.
BOUND STATE IN SUPERCONDUCTORS WITH PARAMAGNETIC IMPURITIES
YU LUH
1965, 21 (1): 75-91. doi: 10.7498/aps.21.75
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A generalized canonical transformation and a SCF method have been used to investigate the influence of isolated impurity atoms on the properties of superconductors. It has been found that a bound state of excitation exists around a paramagnetic impurity with its energy level in the energy gap. An analytical expression has been obtained for the corresponding wave function. The effect of electromagnetic absorption due to the bound state should appear as a precursory peak. The possible experimental verifications of the bound state through tunnelling effect and infrared absorption are discussed.Futhermore, the excitations of continuous spectra around a nonmagnetic impurity and the spatial variation of the energy gap parameter have been considered.
ON THE DECAY BRANCH RATIO OF THE UNSTABLE PARTICLE η:R((η→ππγ)/(η→3π))
TZU PAO-RU
1965, 21 (1): 92-102. doi: 10.7498/aps.21.92
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In this paper, the branch ratio of η→ππγ and η→3π is studied through the analytic continuation of a dispersive relation with respect to the mass of η. It is pointed out that the anomalous threshold and complex singularities are both present. Under appropriateapproximation, we obtain the branch ratio R ((η→ππγ)/(η→3π))≈0.65, which is close to recentexperimental results.
Кl3 РАСПАД
1965, 21 (1): 103-113. doi: 10.7498/aps.21.103
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THE PRINCIPLE OF MAXIMUM ANALYTICITY AND SOME PROPERTIES OF THE REGGE TRAJECTORIES
YIN PONG-CHENG, YEH PENG-SHENG, CHANG CHUN-TING
1965, 21 (1): 114-120. doi: 10.7498/aps.21.114
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Some properties of the Regge trajectories are investigated on the basis of the principle of maximum analyticity. It has been shown that the Regge trajectories corresponding to the different particles are monotonic increasing functions of energy below the threshold and the asymptotic limits of every trajectory are the same for t→±∞. In particular, the vacuum Regge trajectory has nonlinear feature when -t0p(0) must satisfy the inequatily 1/t0p(0)0 is thevalue of t when αp(t=-t0)=0.
CRITICAL MAGNETIC FIELD OF A SUPERCONDUCTING ALLOY FILM
WU HANG-SHENG
1965, 21 (1): 132-139. doi: 10.7498/aps.21.132
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In this paper, the theory developed in previous paper is extended to a thin superconducting film containing impurities. The critical magnetic field for the second order phase transition of the superconducting alloy film has been obtained. The results obtained are reduced to those of the Ginzburg-Landau theory when 2d 》ξ0 with arbitrary l or 2d《ξ0 with l《2d, but are different when 2d0 with l>2d, l being the mean free path of the electrons. The theory agrees with Blumberg's experiment.
THE α REDUCED WIDTH OF lp SHELL NUCLEI
WANG FAN, CHEN CHIN-CHUAN, SZE SHIH-YUAN
1965, 21 (1): 140-153. doi: 10.7498/aps.21.140
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Using shell model wave functions the a reduced width of some \p shell nuclei is calculated. From the results of calculation it is noticed that for normal parity levels, the calculated values are in agreement with the experimental values, while for nonnormal parity levels, the calculated values are always much less than the experimental values. This means that at least for describing the nonnormal parity states shell model wave functions without suitable modification are not sufficient.
DISLOCATION DAMPING IN NICKEL-CARBON SOLID SOLUTION IN THE PROCESS OF PLASTIC DEFORMATION
T. S. KE, C. Y. CHANG
1965, 21 (1): 154-160. doi: 10.7498/aps.21.154
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Low frequency damping in the process of plastic deformation of nickel containing various amount of carbon was measured on a small tensile testing machine. A series of internal friction peaks was observed on the internal friction-strain curve when the specimen contained a suitable amount of carbon. A study was made on the effect of heat treatment, previous cold-working, and temperature of measurement on this internal friction. It is suggested that the series of internal friction peaks is associated with the alternate anchoring of dislocations by atmospheres of solute atoms and their subsequent escaping in the course of plastic deformation.
SEVEN NEW HEXAGONAL POLYTYPES OF SILICON CARBIDE
KUO CHANG-LIN
1965, 21 (1): 161-170. doi: 10.7498/aps.21.161
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A method for determining the hexagonal polytypes of silicon carbide using the Laue pattern is described. By the detailed studies on reciprocal lattice points of various hexagonal types xH of silicon carbide which are coalescent with 6H, 15R or 4H, the relations of the arrangement of their diffraction points has been derived. It is proved that there are twelve kinds of relation for the coalescence of xH with 6H, thirty for xH with 15R and eight for xH with 4H. The relations and the formulas which are given in this paper for the calculation of the numbers of hexagonal packed layers in unit cell of xH may be applied not only to the Laue technique but also to other x-ray techniques.A great number of single crystals of silicon carbide grown in laboratory by the sublimating procedure and of technical silicon carbide had been studied. Seven new hexagonal types 141H, 80H, 58H, 55H, 15H, 9H and 7H were found. The space group of all these new polytypes was determined to be C3m, and their lattice parameters c in the hexagonal cell are 355.26?, 201.57?, 146.14?, 138.58?, 37.794?, 22.676? and 17.637? respectively.
MATRIX ANALYSIS OF PULSE WAVE PROPAGATION ON MULTI-CONDUCTOR TRANSMISSION SYSTEM
S. T. BOW
1965, 21 (1): 171-190. doi: 10.7498/aps.21.171
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In this paper the propagation of pulse wave on and the mutual coupling between conductors of a multi-conductor transmission system are analysed from the basic voltage and current equations. It is found from the analysis that on a completely transposed double-circuit three-phase system there will exist four pulse waves of different velocities originated from a system disturbance, and accordingly there will be four different values of the characteristic impedance. With these relations obtained, some peculiar phenomena of pulse wave propagation on lines can be explained, and the distortion, reflection, and refraction, etc., of waves can be computed according to given boundary conditions, thus giving theoretical support to practical measurements on lines. Examples are given to illustrate the method of analysis.The pulse wave propagation analysis is further extended to the steady-state alternating current operating condition, and equivalent sequence networks are derived for power system studies.
THE (dp) STRIPPING REACTIONS WITH THE TARGET CORE EXCITATION
CHIU SIH-TJUEN
1965, 21 (1): 208-217. doi: 10.7498/aps.21.208
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The present paper studies the (dp) stripping reactions with the target core excitation. In this case, we assume that the target nucleus and the residual nucleus contain the conventional shell model configuration and other configurations mixed by the nucleon-nucleon residual interaction.We derive the differential cross section formula for the reaction process based on the above assumption. The formula shows that the contribution to the reaction cross section is mainly due to the configuration mixing of target nucleus. We may expect that the cross section values are rather small, because the admixture in general is weak. The formula also shows that the characteristic peak of the reaction angular distribution is determined by the orbital angular momentum quantum number of the hole state which is created during the core excitation. These two conclusions are consistent with experimental results for this type of reactions.We apply this formula to calculate the "spectroscopic factors" for six reaction events. The theoritical values of the "spectroscopic factors", within the experimental errors, agree with those extracted from the experimental data.
BRIEF REPORT
1965, 21 (1): 218-220. doi: 10.7498/aps.21.218
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1965, 21 (1): 221-222. doi: 10.7498/aps.21.221
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1965, 21 (1): 223-226. doi: 10.7498/aps.21.223
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1965, 21 (1): 227-230. doi: 10.7498/aps.21.227
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1965, 21 (1): 231-234. doi: 10.7498/aps.21.231
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