NON-ITERATIVE METHODS FOR RESOLUTION OF RADIOACTIVE DECAY CURVES (Ⅰ) RESOLUTION OF THREE-COMPONENT DECAY CURVE WITH A DECAY CONSTANT BEING KNOWN

A method without iterative procedure is presented for resolution of a three-component decay curve with a decay constant being known.Artificial decay data have been used to test the present method and good results have been obtained.     

NOVEL SYSTEMATICS OF AUTOIONIZATION AND RADIATIVE DECAY RATES OF DOUBLY EXCITED STATES OF ATOMS

We discuss the novel systematics and the calculation of autoionization and radiative decay rates of doubly excited states of atoms and ions where both electrons have high principal quantum numbers.     

THEORETICAL ANALYSIS OF SCATTERING OF ULTRASONIC PULSES BY RIBBON-TYPE CRACKS IN SOLID——GENERAL SOLUTION

Scattering of elastic waves by obstacles of various shapes,especially those having sharp edges,is an important problem in NDE.The problem of scattering of a plane longitudinal or SV ultrasonicpulse in a solid,by a crack of finite width with free faces,is investigated in this paper by applyingdouble Laplace transforms and the generalized Wiener-Hopf technque.A solution in the Laplacedomain is obtained.An approximate form of this solution is then formulated neglecting the higher-order multiple scatterings,which can be inverted by the Cagniard-de Hoop method.The approximatesolution in the time-space domain gives the major features of scattering in the early time and henceof the near field.The result is readily shown in pictorial form. We have experimentally studied the corresponding scattered field in glass by the use of the photo-elastic visualizing technique,but the results are not included here,except for one photoelastic picturefor illustration.     

MULTIDIMENSIONAL ANALYSIS OF PERCEPTIONAL CONFUSION OF CHINESE CONSONANTS

The perceptional features of Chinese consonants has been analysed in multidimensional scalingby means of optimizing the fitting to the confusion probabilities of consonants as observed in articula-tion tests.The dependence of minimum Stress as criterion for fitting on dimensions has beenobtained. In this paper,a method of multidimensional scaling is described briefly.A program for perform-ing calculations on a programmable calculator and the questions of handling the blank data as wellas setting the starting configurations are discussed.Some typical results of calculation are given.     

ANALYSIS OF SURFACE EXCITATION OF ELASTIC WAVE FIELD IN A HALF SPACE OF PIEZOELECTRIC CRYSTAL——GENERAL FORMULAE OF SURFACE EXCITATION OF ELASTIC WAVE FIELD

This paper developes the general theory of the surface excitation of elastic wave field in a halfspace of piezoelectric crystal for both free and metallized surfaces.It is shown that the general elas-tic wave field U is equal to the convolution of the generalized Green's functions G and the general-ized forces T, U = G Twhere symbol,expresses dot-product-convolution. The generalized Green's functions are independent of excitation conditions and only dependenton material parameters and orientation. For the piezoelectric crystal,not only a mechanical source distribution at the surface,but anelectrical source distribution can also excite the elastic wave fields.Complete expressions of thegeneralized forces representing mechanical and electrical source distribution respectively are given.Especially for the free surface,the surface electrical sources can be composed of the discontinuityof normal electric displacement at the surface,and of the discontinuity of the tangential electric fieldas well.     

DECAY PROCESSES OF HIGH-FREQUENCY NONEQUILIBRIUM PHONONS IN PRASEODYMIUM-DOPED LASER CRYSTALS

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ANALYSIS OF INDIVIDUAL MODES IN SHALLOW WATER

The propagaion experiment of explosive sound in the isothermal layer below the thermocline wasmade,and the records of individual modes for the frequencies of 0.32 to 1.0 kHz were obtained.Byanalyzing the travel time of filtered signal,it was determined that the recorded waveforms are the firstmodes.On the basis of the propagation properties of the first modes,the bottom-reflection coeffi-cients at small grazing angles for the frequencies of 0.32 to 1.0 kHz were obtained.     

FINITE ELEMENT ANALYSIS OF THE YONGLE BELL

The Great Bell of Yongle cast in the reign of Yongle of the Ming Dynasty is a bell for prayer.By use ofthe finite element method for the calculation of truncated conical shell,natural frequencies and vibrationalmodes of the Yongle Bell have been calculated.Theoretical results are consistent with those obtained frommeasurements of sound.Within the range of calculation,the law of distribution of nodal circles for eachvibrational mode is presented.Through comparison between the Yongle Bell and assumed bells,theinfluences of waist and lip thickness changes on the bell timbre are discussed.The tuning for A_3 and E_3partial tones is achieved by changing the thickness at waist and lip.These partials play a harmonious part inthe bell sound.     

USING STATISTICAL ENERGY ANALYSIS IN STUDY OF SOUND INSULATION OF PARTITIONS

The models of Statistical Energy Analysis(SEA)of sound insulation of partitions,single wall,double wall and double panels connected by studs,are made.The evaluation of the parametersof SEA is discussed.Gypsum board walls are used as objects of study.Radiation resistance,lossfactor and sound transmission loss are measured.The sound insulations of seventeen types ofgypsum board walls are calculated by computer.Agreement between calculated results and experi-ments is found to be good.Finally,the influence of some factors,such as parameters of room,damping loss of wall,absorption material in cavity and form of stud,upon the sound insulationof walls is discussed.     

A FURTHER STUDY OF QUASI RESONATING GROUP METHOD—— ANALYSIS OF p+6Li ELASTIC SCATTERING

In this paper,the elastic scattering of p+⁶Li is studied by 3QRGM,a three-cluster RGM omitting the antisymmetrization with the nucleon in the double magic cluster.The main conclusion from studying the systems of p+⁶Li and n+⁶Li is the following:The clustering and exchange effects lower the phase shifts conspicuously.hence they are very important in the lower energy region.     

ANALYSIS OF F′0+u ION-PAIR STATE OF IODINE

The optical-optical double resonant multiphoton ionization (OODR-MPI) technique and the fluorescent excitation spectroscopy technique have been applied to the study of the F′0⁺_u ion-pair state of iodine. This paper presents OODR-MPI spectrum and fluorescent excitation spectrum of I₂ in the region of 54000-55300cm^-1 by the three-photon resonant, two-photon ionization (1+2+2) and (1+(1+1)+2) processes.     

SPECTRUM ANALYSIS OF SPEECH SIGNAL BY COHERENT OPTICS

The technique for realizing spectrum analysis of speech signal using coherent optical system ispresented.By sacrificing the multichannel capability of such an optical system,speeh signal withlarge time bandwidth product can be analyzed.The principle of the system is briefly indicated andsome experimental results are also provided.     

THEORETICAL ANALYSIS OF REAL-TIME AIR-GAP COUPLED SAW CONVOLVERS

In this paper,a new theory is developed for the analysis of real-time air-gap coupled SAWconvolvers.There are two important features about the theory proposed here.Firstly,we rigorouslyconsider the role of the surface states of semiconductors in acoustoelectric nonlinear interactions.Secondly,by means of a new equivalent circuit for such a convolver,we derive various new analyticalexpressions which describe the linear coupling coefficient for air-gap,nonlinear coupling coefficientfor acoustoelectric nonlinear interactions,and convolution output(or figure of merit);these expres-sions exhibit obvious dependence on bias.The frequency response of the surface states is also ana-lyzed. The theory presented here is a general formula applicable to dealing with the situation when thesemiconductor surface is accumulated,at flat-band,depleted,or inverted. The presented theory can essentially explain experimental results of SAW acoustoelectric non-linear interactions which were carried out by the author and others.     

ANALYSIS OF LOADED ULTRASONIC AMPLITUDE TRANSFORMER BY MEANS OF MBIUS TRANSFORMATION

Mobius transformation is used to analyze the loaded amplitude transformer in a high powerultrasonic system.Several features of the vibrating horn can be predicted from the mapping:thedependence of the input impedance,the points of equal impedances,the condition of resonanceand the working stability.Limited experimental verification has been effected.     

ANALYSIS AND PRACTICE OF FACTORS AFFECTINGPHYSICAL EXPERIMENT TEACHING RESULTS

本文讨论了影响物理实验教学效果的五个方面的因素,并探讨了如何加强实验内容和方法的改革,加强设备和环境的管理,充分调动人的能动性,提高教学质量,以适应时代发展需要。     

DYNAMIC SPECTRAL ANALYSIS OF INFRASONIC SIGNAL WITH HILBERT TRANSFORM

In the past we analyzde the dynamic spectrum of infrasonic waves with FFT,but that isnot suitable to this analysis in any case.In this paper another method is proposed to analyzeinfrasonic waves.This method is that,after digital filtering of the signal and Hilbert transform,this paper the computation of the envelope with Hilbert transform and 1/12-octave filter are dis-cussed.Then a synthetic infrasonic signal generated by a large nuclear explosion is analyzed withthe two methods,and their results are compared.It is shown that,in the dynamic spectrum,usingHilbert transform,not only higher resolution is obtained,the main frequency range of separatedmodes can be achieved,but also their waveform can be obtained preliminarily for some modes.Thus it seems that in some cases this method is more efficient for discovering the characteristicsof an infrasonic signal.     

UNIFIED ANALYSIS OF EXCITED NUCLEONIC AND Δ'S SPECTRUM

In this paper it is assumed that the quark-quark two-particle interaction is the coulomb-like plus exponential type confinement potential. The excited nucleonic and Δ's spectrum below 2 GeV has been stutied unifiedly by the potential. The calculated position of the resonances and the predicted mixing angles are in good agreement with the experiments. It is shown that the potential can describe successfully the properties of the low-lying non-strange baryon states.     

NONLINEAR STABILITY ANALYSIS OF THE EMDEN–FOWLER EQUATION

In this paper, we qualitatively study radial solutions of the semilinear elliptic equation Δu+uⁿ = 0 with u(0) = 1 and u′(0) = 0 on the positive real line, called the Emden–Fowler or Lane–Emden equation. This equation is of great importance in Newtonian astrophysics and the constant n is called the polytropic index.

By introducing a set of new variables, the Emden–Fowler equation can be written as an autonomous system of two ordinary differential equations which can be analyzed using linear and nonlinear stability analysis. We perform the study of stability by using linear stability analysis, the Jacobi stability analysis (Kosambi–Cartan–Chern-theory) and the Lyapunov function method. Depending on the values of n these different methods yield different results. We identify a parameter range for n where all three methods imply stability.     

EXCITATION CURVES FOR SOME REACTIONS OF Al、Ti、V AND I

Excitation curves for the reaction ²⁷Al（n,α）²⁴Na,⁴6Ti（n,p）⁴⁶Sc,⁴⁸Ti（n,p）⁴⁸Sc,⁵¹V（n,α）⁴⁸Sc and ¹²⁷I（n,2n）¹²⁶I have been measured by the activation method in the4.5—18.3 MeV energy region.The cross section for the reactio ²⁷Al（n,α）²4Na was determined at 14.61±0.20 MeV.The measurement of neutron flux was performed using the associated particle method.The cross sections for other reactions were de-termined relative to the measured ²⁷Al（n,α）²⁴Na cross section.The resulting activities were measured employing a calibrated NaI（TI）scintillation counter.The values obtained were 117.5±3.0 mb,291.4±14.0mb,63.7±3.2 mb,16.8±0.9mb and 1656±68 mb respectively.A brief comparison with existing data was made.