STATICAL SPHEROSYMMETRICAL SOURCELESS SOLUTION OF SU(2) GAUGE FIELD——THE SELFDUALITY,UNIQUENESS AND THE SELF INDUCED CHARGE CURRENT

It is shown that the statical spherosymmetrical sourceless solutions of SU(2) guagefield,which satisfy a physical boundary condition,must be selfdual.Then from theselfdual condition,we solve the equation explicitily,hence show the uniqueness analy-tically.By gauge transforming the Lagrangian by a local generator of synchrono-symmetry,we get a corresponding local charge current density,which is both gaugeinvariant and conserved.The total values of either electric or magnetic charge arequantized,but the charge distributions in space are continuous and not restrictedby quantization.Finally we discuss a mechanism of spontaneous symmetry break-down.Contrary to ordinary magnetic flux string,now the ordered phase is surround-ed by the normal phase,the ordered phase repels electric fields,and electric fieldsdestory the ordered phase.     

THE EFFECT OF ELECTRIC LOAD ON THE CHARACTERISTICS FOR PIEZOELECTRIC VIBRATIONAL SYSTEM

The effect of electric load on the piezoelectric vibrational system due to electroacoustic coupling isanalytically investigated.The analytical results show that:(1)when load impedance continuallychanges from ∞to+∞,the mechanical resonant frequency of the system would fill all frequencydomain from 0 to ∞;(2)the displacement and stress distributions also would change,even the dis-placement may be zero at both free ends(i.e.at points where stress is equal to zero). Finally,the experiments for longitudinal vibration of piezoelectric strip of lateral polarizationare given and compared with theoretical results.     

CALCULATION ON A CLUSTER MODEL FOR THE ELECTRONIC CHARGE DENSITY AT NUCLEAR SITE AND THE ELECTRONIC STRUCTURE PARAMETERS OF α IRON

In order to investigate the M6ssbauer isomer shifts and its related electronic charge densities for some substances, the electronic charge density at nuclear site of a iron have been computed for an octahedral cluster Fe₆ with SCF MS-X_α method. Some other electronic structure parameters of the cluster have also been obtained, such as the orbital energy distri- bution, the electron density of states, the Fermi level and various kinds of electron energies, etc. The cohesive energy of α iron have also been calculated and discussed.     

RIGHT TRANSLATION INVARIANT METRICS AND VARIATIONAL PRINCIPLES ON A PRINCIPAL BUNDLE——TREATED AS THE UNION OF SPACE-TIME AND AN INTERNAL SPACE

In this paper, we discuss how to assign a metric on a principal bundle and howto rewrite the variational principles for a particle and for matter fields in an inva-riant from on the bundle in the principal-bundle formulation of gauge theories. Weshow that the right-translation invariant metric on the bundle must contain quantitieswhich transform exactly as gauge potentials, thus providing a new formalism for gaugefields. And we formulate the variational principle for a particle moving in the gaugefield as follows: The particle moves along a horizontal geodesic on the principalbundle. Starting from this we derive the Wong's equations of motion. Moreover, we elucidate the physical view-point which treats the bundle space asthe union of space-time and the internal space. Advantages of this viewpoint for un-derstanding the essentialities of gauge transformations and gauge invariance and forestablishing unified theories of gravitation and gauge fields are also discussed.     

THEORETICAL CALCULATION OF LINEWIDTH PARAMETERS FOR THE MICROWAVE SPECTRUM AND DEPOLARIZED RAMAN SCATTERING OF O_2—He SYSTEM

The shape of the spectral line is determined by the ieteractions of theradiating molecule with its surroundings.Study of the microwave and Ramanline shapes arising from the O_2 deluted in He will yield information con-cerning the basic intermolecular forces and molecular collision dynamics forthis system~1,also spectral linewidth parameters can give informatioll for thestudy of ejected gas at the rear of the plane and missile. The exact calculation of line shape spectral function is extremely timeconsuming,and has not been attempted.At low pressure individual spectral tran-sitions are well resolved,we are interested in the linewidth parameters.Calcu-     

THE BETHE-SALPETER EQUATION FOR SPIN (0—3/2) ELECTROMAGNETIC BOUND SYSTEM AND ITS APPROXIMATE SOLUTION

In this paper. the Bethe-Salpeter equation for spin (0—3/2) electromagnetic bound system is derived. Under the ladder approximation the approximate B-S wave function with accuracy up to order 0(α) for this system is obtained. Utilizing this wave function, we estimated the cross section for producing (π⁺Ω^－) in Ω^－-p collision process.     

ON THE IRREDUCIBLE REPRESENTATIONS OF THE SIMPLE LIE GROUPS I——THE TENSOR BASIS FOR THE INFINITESIMAL GENERATORS OF THE CLASSICAL SIMPLE LIE GROUPS

In this paper, we analyse the commutation relations of the infinitesimal generatorsof all simple classical Lie groups and establish a new basis for these generators, calledthe tensor basis. In tensor basis, the infinitesimal, generators can be written as somescalar operators, some sets of angular momentum operators and some sets of irreducibletensor operators. The commutation relations, of these operators are very simple andhave many regularities. By means of the method that has been used in the earlier papers, "On the irre-ducible representations of the compact simple Lie groups of rank 2, I,II,III" and thetensor basis, all the irreducible representations of the classical simple Lie groups canbe calculated systematically.     

THE ENERGY SPECTRUM AND WAVEFUNCTION OF NUCLEUS 31Si——A TEST ON THE COMPOSITE PARTICLE REPRESENTATION THEORY

The nuclecus ³¹Si₁₇ is studied by the composite particle representation theory and compared with the shell model calculations. It is shown that the entire energy spectrum agrees with the shell model results very well, and the wave function is equivalent to the shell model wavefunction exactly. Therefore it strongly supports the composite particle representation theory.     

THE EFFFECTS OF THE QUANTITY OF SUSPENDNDED DIFFUSERS AND SPECIMEN AREA ON THE TEST RESULTS FOR SOUND ABSORPTION COEFFICIENT IN A SMALL REVERBERATION CHAMBER

The diffusivity of the sound field in a reverberation chamber,which can be improved by dif-fusing elements hanging from the ceiling of the room,usually has a significant effect on the test resultsof sound absorption measurement.We have found that the diffusivity is sufficent when the totalarea of suspended diffusers reaches 60—70% of the floor area in a small chamber,say about 100 m~3.But for some acoustical materials such as perforated fiber tile,we have found the sound absorptioncoefficients are considerably independent on diffusivity.It can be concluded that the acoustical propertyof such material varies little for different angles of incident wave,hence they are not be suitable in usefor the determination of the diffusion improvement of sound field. Test results of many commonly used acoustical materials show that when test specimenarea changesfrom 10m~2 to 6m~2,provided that the ratio of length to width is controlled between 0.7 and 1.0,thedeviation of the sound absorption coefficient obtained is r     

GENERALIZED SIEGMAN FORMULA AND COMMENTS ON THE INEQUALITY M2≥1 FOR LIGHT-BEAM QUALITY

An generalized version of the Siegman formula which comes directly from Helmholtz equation is reported in this paper. Based on this formula, a comparison between the two definitions of the light beam far-field divergence angle is made. It is discovered the Siegman's moment definition for divergence angle would not make sense if the light beam could not be approximated to the slowly varying one. The proof of inequality M²≥1 given by Chen and Qiu would fail if the evanescence wave effects are considered.     

EFFECT OF α-Fe SURFACE LAYER ON THE MAGNETIC REVERSION PROCESS FOR Nd2Fe14B CRYSTAL

The demagnetization process for a Nd₂Fe₁₄B grain covered by an α-Fe layer was studied by use of the finite element technique of micromagnetics. μ_0iH_c decreases with the increase of α-Fe layer thickness t. With the increase of t from 0 to 6nm, μ_0iH_c decreases from ～7 T to ～3.5 T when the angle between the applied field and the c-axis of the Nd₂Fe₁₄B grain is 0.5° and from ～4 T to ～1.5 T when the angle is 30° or 60°. The effect is only slightly affected by the angle between the α-Fe layer and the field direction.     

A FINITE ELEMENT/BOUNDARY ELEMENT——MODIFIED MODAL DECOMPOSITION METHOD FOR VIBRATION AND SOUND RADIATION FROM SUBMERGED SHELL OF REVOLUTION

A finite element/boundary element—modified modal decomposition method(FBMMD)ispresented for predicting the vibration and sound radiation from submerged shell of revolution.Im-provement has been made to accelerate the convergence to FBMD method by means of introducingthe residual modes which take into account the quasi-state contribution of all neglected modes.Asan example,the vibration and sound radiation of a submerged spherical shell excited by axisymmetricforce are studied in cases of ka=1,2,3 and 4.From the calculated results we see that the FBMMDmethod shows a significant improvement to the accuracy of surface sound pressure,normal displace-ment and directivity patterns of radiating sound,especially to the directivity patterns.     

INVESTIGATION ON THE VALEN CE STATE OF Ce ATOM IN BULK AND nANOCRYSTAL CeO2 BY X—RAY ABSORPTION AND PHOTOEMISSION

Valence band photoemission spectra(PES) for both bulk and nanocrystal CeO2 have been masured on and off resonance of Ce 4d-4f absorption edge.The PES show that the bulk and nanocrystal CeO2 of diameter ranging from 8nm to 50nm exhibit a peak near Fermi edge with binding energy of abiyt 1.8eV peak shows a strong dependence on excitation energy,although it looks like the contribution of Ce^3 ion following the data reported in literatures.However,According to the results of resonance photoemission and X-ray absorption spectra at O 1s edge,this electronic structure may be associated to the intermediate state charge transfer effcets.     

STATISTIC PROPERTIES OF NOISE FIELD OF MOVING SOURCE IN SHALLOW WATER AND ITS EFFECTS ON SIGNAL PROCESSING FOR THE NOISE RANGING SONAR

In this paper the properties of space-time correlation function of the noise field of moving source inlayered statistic inhomogeneous medium are studied and the effects of random fluctuating boundary are con-sidered as well.It has been shown,theoretically and experimentally,multi-path propergating effects cause thedispersion of the correlation function and fluctuations of the medium refraction index and the boundarycause the fluctuation of it.The effect of the movement of the noise source on the output of real-time correlator is equivalent to alow-pass filter added the drift of space-time correlation function.These properties of the correlation function cause grave degradation of the signal processing gain ofnoise ranging sonar system.The fluctuating and the distortion of conrrelation function made it difficult to realize the noiseranging.So in this paper,a method of space correlation ranging by a linear array of four points with shortseparation and long span and a technigue of dual-correlation signal p     

XAFS CHARACTERIZATION ON THE ACTIVE SITES OF Ni／γ—Al2O3 CATALYSTS FOR NO—SCR BY PROPENE

Ni/γ-Al2O3 catalysts show high catalytic activity for the selective catalytic reduction of NO by C3H6.The microstructures of nickel species were characterized by the spectroscopy of X-ray Absorption Near Edge Structures(XANES) and Extended X-ray Absorption Fine Structures(EXAFS).The resuts of XANES and EXAFS indicate that the nickel species in the sample calcined at 500℃mainly exist as highly dispersed NiO phase,Whereas in the samples calcined at750 and 950℃,the nickel species mainly exist as NiAl2O4-like spinel.The surace NiAl2O4-like spinel is the main active site for the selective reduction of No,and the highly dispersed NiO phase is the main active site for C3H6 oxidation. The formation of subsurface or buld NiAl2O4 spinel results in the reduction of surface spinel and cuases the decrease of activity for the selective catalytic reduction of NO by propene.     

THE BOUND STATE ENERGY LEVELS OF MONOPOLE PAIR AND OF CHARGED MONOPOLE-ELECTRON SYSTEM—SOME SINGULAR STATE PROBLEMS IN RELATIVISTIC QUANTUM MECHANICS

In this paper four kinds of singular state problems in relativistic quantum me-chanics and its solutions are summarized. In the references [2,3,5,6,11], it hasbeen pointed out that in some quantum mechanial problems involving singular statesthere exists phase angle uncertainty. The principle eliminating this kind of nncer-tainty——the orthogonality-variation principle has been obtained in [11] The re-sults of scattering and bound state problems of a neutral monopole and a chargedDirac particle are consistent with those obtained by C. N. Yang, Kazama, and Gold-haber. In [5], [11] and this paper the Case-type equations determining the boundstates of monopole pair and exotic atoms consisting of a charged monopole and anelectron are obtained. In this paper these energy levels are calculated numericallyBecause in these equations the number of singular points is infinite and the rune-tions oscillate rapidly, usual calculation methods are not suitable in these cases. Afteranalysing these equations and determining the positions of singular points and theranges of energy levels, these energy levels are calculated by computer. It is pointed out that the number of these energy levels is infinite and the posi-tions of positive and negative energy levels are asymmetric. The negative energylevels do not appear untilεis very near -1. The values of the positive energy levelsare spread in the range 0.9998ε<1 They are near those of the hydrogen-like atomand similar to those of impurity in solid. This is a perturbation problem of singularstates to which the usual perturbation theory can not be applied. The energy levels of monopole pair are not similar to those of the hydrogen-likeatom. In the range 0<|ε|≤0.99 there are many energy levels with positive andnegative energy. It is also pointed out that for the hydrogen-like atoms, 119<z<137, somenegative energy bound state solutions satisfying square integrability condition arepossible. The ordinary standard condition does not exclude these states, but the or-thogonality criterion does exclude them. The conclusion is in agreement with thatreached by Professor C. N. Yang. The results shown suggest that the orthogonality-variation principle is reasona-ble.