OSCILLATIONS DRIVEN BY 3He IN THE NUCLEAR REACTIONSYSTEM DISTURBED BY CONVECTIVE MOTION

The nuclear reactions in the solar interior are always influenced by the effects from convection, diffusion,pressure,gravitation,etc.,among which the convection is primarily responsible for driving the instability.On the basis of the charact eristic with which the particle number density of chemical compositions changes, we investigate the dynamical behaviors driven by ³He in the proton prot on nuclear reaction chain disturbed by convective motion with the aid of nonequi librium dynamics.The new supercritical oscillations of ³He are found in producing and destroying ³He in the nuclear reaction zone of the sun.The energy generation is therefore oscillating,and then this might change the predicted ⁸B and ⁷Be neutrino fluxes.     

SIGNAL SEPARATION THEORY BY USING ADAPTIVE ARRAY

Signal separation technique by using adaptive arrays is a new area in array data processing.The model considered in this paper is that of an array consisting of N elements,and the numberof signal sources,which are separated in spatial location,is M and M≤N.In the case of narrowband signals,the pre-envelope form of incidental signal can be obtained from the original signaland its Hilbert transform.In terms of the conventional beamforming system,the directional bearingangle matrix G is formed.By using a special implementation the inverse matrix of G is derived.At last,a matrix transform is operated on the received signal so that the output signal is separable,i,e.each output channel has only one incidental signal.In the case of wide band signals,the DFTof input signal or heterodyne is required.The block diagram of signal separation technique aregiven.Some important results of this technique are derived.The results of system simulationexperiments in digital computers prove that this theory is effective fo     

UNIFORM GROOVE-DEPTH RAC BY USING TRANSDUCER WEIGHTING

A new weighting method,transducer weighting.for the uniform groove-deph RAC is proposed in thispaper.The weighted input and output transducersform a weighting transversal filter In addition,the groove-width weighting,which can be used as an auxiliary is also discussed. By using the new methods,two uniform groove depth RACs have been designed and fabricated,Thesidelobe suppressions achieved are 31 dB and 32 dB.respectively.The results are considered satisfactorybecause the phase compensation by metal strip was not applied.     

ELECTRON CAPTURE PROCESSES BY HIGHLY STRIPPED IONS

The electron capture process by highly stripped ions is currentlyof great importance not only in basic atomic collision physics but alsoin such diverse fields as controlled theromonuclear fusion research,astro-     

DIAGNOSTICS OF ARC PLASMA BY MOIRE DEFLECTOMETRY

This paper presents a new method to diagnose the welding arc temperaturefield on the basis of plasma physics,Talbot effect and Moire techniques.This method hasadvantages of immunity to mechanical shock and vibration,tunable sensitivity and conside-rable simple optical system.     

ACOUSTIC TRANSMISSION ATTENUATION CAUSED BY RANDOM SURFACE

Assuming that the rough surface is a stationary process with a normal distribution,the scat-tering of a plane acoustic wave by this surface is studied.The statistical mean of the reflection coef-ficient and its relation to the correlation radius of the random surface have been discussed.By in-troducing the concept of"the equivalent reflecting plane",a general formula for a field with apoint source in a stratified medium which has a random surface is derived.This demonstrates an easysolution to the additional attenuation coefficient under various sea conditions.The additional attenua-tion coefficients of the normal modes in the surface duct are given in detail.     

SCATTERING OF A GRAZING LONGITUDINAL WAVE PULSE BY A RIBBON-TYPE CRACK—EXPERIMENTAL VERIFICATION BY THE PHOTOELASTIC METHOD

By using the dynamic photoelastic method and our technique of fabricating an internal crack in solid,the scattered waves of incident grazing longitudinal ultrasonic wave pulse by a ribbon-type crack are ob-served and analyzed.In particular,the distribution of the intensity of the scattered head wave is measuredquantitatively.The experimental results fairly agree with the theoretical ones given in ref.[1].     

OSCILLATIONS DRIVEN BY 3He IN THE NUCLEAR REACTIONSYSTEM DISTURBED BY CONVECTIVE MOTION

The nuclear reactions in the solar interior are always influenced by the effects from convection, diffusion,pressure,gravitation,etc.,among which the convection is primarily responsible for driving the instability.On the basis of the charact eristic with which the particle number density of chemical compositions changes, we investigate the dynamical behaviors driven by ³He in the proton prot on nuclear reaction chain disturbed by convective motion with the aid of nonequi librium dynamics.The new supercritical oscillations of ³He are found in producing and destroying ³He in the nuclear reaction zone of the sun.The energy generation is therefore oscillating,and then this might change the predicted ⁸B and ⁷Be neutrino fluxes.     

IDENTIFICATION OF MACHINE TROUBLE BY SPECTRUM CORRELATION METHOD

A method for identifying the troubles in a machine by its vibration is developed.Firstly thevibration of the machine to be analysed is transformed from time domain into frequency domainto get the logarithmic power spectrum N_(xx)(f).The correlation between two of these logarithmicpower spectra is derived.Before the correlation operation,N_(xx)(f) and N_(yy)(f) are normalizedwith their average values and the“DC component”1 is subtracted from their normalized values. The analysis of machine noise indicates that the spectrum correlation coefficient between themachine vibration and its original record when it was in good reduced,should some trouble bedeveloped.Furthermore,the spectrum correlation coefficient between the vibrations of the samemachine with different kinds of trouble is smaller than that for the same trouble but larger thanthat between the noises when the machine works normally and abnormally. Consequently,by selecting a certain threshold of spectrum correlation,identification of differenttro     

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.     

REFLECTIVE CHARACTERISTICS OF SAW BY SLANTING METAL STRIP ARRAYS

The reflective characteristics of SAW by slanting metal strips on the surface of YZ-LiNbO_3 havebeen studied.By using both Simple Model and Multi-Reflection Model,the reflective characteristics ofSAW by a periodic metal strip array and the SAW distribution in the array have been calculated.Furthermore,By using an improved laser probe,the reflective SAW field by the array has also beenmeasured.By comparing the theoretical results with the experiments,it is shown that the results of Mul-ti-Reflection Model,being more exact than the Simple one,are in better agreement with the experiment     

MULTIPLE ELECTRON CAPTURE PROCESSES BY HIGHLY CHARGED IONS FROM ATOMS

Recent observations for multiple electron transfer processes inslow highly charged ion-atom collisions are presented,by usingthe ejected electron spectroscopy and the translational energygain spectroscopy.     

DIRECTIONAL CHARACTERISTICS OF THE SOUND RADIATED BY ELLIPTIC CONE BELL

Elliptic cone shells have been used as the model in the study of directional characteristics ofchime bell sound.Radiation patterns are obtained experimentally and compared with the calculatedradiation patterns for elliptical ring source.The number of lobes in the radiation patterns is equalto the number of meridian nodal lines on the vibrating shell.The radiation patterns is symmetricalfor one of the principal vibration modes and dissymmetrical for another principal mode.     

STUDIES ON LOW ENERGY ION-ATOM COLLISIONS BY MEANS OF ELECTRON-SPECTROSCOPY

We present typical results of studies on autoionizationprocesses produced by low energy ion-atom collisions bymeans of the ejected electron spectroscopy,which havebeen performed by Atomic Physics Group of SophiaUniversity.     

EXPERIMENTAL STUDY OF IONIZATION CROSSSECTIONS OF ATOMIC IONS BY ELECTRON-IONCOLLISIONS

Worldwide demands for quantitative information on the electron-ioncollisions from both the field of the controlled thermonuclear fusion andof the space science have caused significant promotion in efforts in experi-mental study to determine cross sections for electron collisions with ions.     

VIBRATION OF IMMERSED RECTANGULAR COMPOSITE PLATE EXERTED BY UNDERWATER SOUND

Based on the theory of elastisity,according to the principle of least elastic energy and variationalmethod,the position of neutral surface of the elastic composite plate system is determined.And then,the governing equation for the flexural vibration of composite plate system is derived.After intro-ducing the equivalent rigidity,Poisson's ratio and surface mass density,the governing equation andboundary conditions of this plate system may be deduced in the form similar to those of thin platewith same boundary conditions.The governing equation for bending motion of elastic-viscoelasticcomposite plate system is derived from the theory of viscoelasticity.Then,the effective damping con-stant of plate system may be calculated by dynamic constants of material of these plates.A generalsolution for the bending motion of plate system is given by the method of normal mode analysis andFourier analysis.As an example,a simply-supported rectangular composite plate system is concerned.The equivalent rigidity,Poisson's r     

CALCULATION OF SOUND INSERTIONLOSS OF A BARRIER BY FRESNEL ZONE METHOD

In this paper the formulas are presented to estimate the sound pressure amplitude at the observationpoint behind a half-infinite sound barrier,especially in the shadow region.The barrier may be a thin screen,or awedge,or a wide barrier These formulas are based on the Huygens-Fresnel principle of diffraction and on theconcept of Fresnel half-period zone.By using these formulas a new method,Fresnel Zone Method,to calcu-late sound insertion loss of a barrier is obtained.The calculations agree well with the experimental results.     

DAMAGE DISTRIBUTION OF LiNbO3 CRYSTAL INDUCED BY C^＋ IMPLANTATION

The Y-cut X propagating LiNbO_3 crystals were implanted with afluence of 5×10~(13)-5×10~(14) C ions/cm~2 at energies from 100 to200keV,respectively,The implanted LiNbO_3 crystals were anal-yzed using Rutherford backscattering/Channeling technique.Theresult shows that:(1)the damage ranges are systematically higherthan the projected ranges calculated from TRIM(Transport ofIons in Matter)simulation,and the damage widths are significa-ntly broader than TRIM values;(2)the total disorder inducedby carbon ion In LiNbO_3 is not linearly increased with the imp-lanted fluence.     

STUDY OF MESOPOROUS SILICA MATERIALS BY SMALL ANGLE X—RAY SCATTERING

Small angle X-ray scattering experiments have been performed to study the microstructure of messoporous silica meterials prepared by condensation of tetraethylorthosilicate using nonionic alkylpolyethyleneoxide(AEO9) and ionic cetyltrimethylammonium bromide (CTAB) surfactant as templates.It is the pores within the nanometre range that produce the main cattering.The scattering of the pure silica systems obey Porod’s law.This may be because the templates produce some additional scattering background and then make the scattering of pores distorted.The results show that the full removal of templates from the pores of the materials by Soxhlet extraction is very easy for AEO9,but it is difficult for CTAB.The positive deviation correction is also perfromed.