PHASE SEPARATION IN THE MELT OF POLYPROPYLENE–1-DECENE COPOLYMERS

A propylene homopolymer and three copolymers with 1-decene containing 1.82, 3.55, and 7.83 mol% of comonomer units, respectively, were prepared with metallocene catalyst and the phase behavior in the melt of these polymers was studied using simultaneous synchrotron small-angle x-ray scattering and differential scanning calorimetry. The results show that the phase behavior of the melt varies with comonomer content and the copolymers tend to be phase-separated with increasing comonomer content. The phase separation in the melt of the propylene–1-decene copolymers was further confirmed by the fitting of the experimental data with Teubner–Strey micro-emulsion model and a transition from the phase-separated melt to the disordered melt was observed. We tentatively attribute this phenomenon to the inhomogeneous intra-molecular composition distribution at high levels of comonomer and the incompatibility of propylene sequences with different lengths. Such a finding is consistent with the facts of multiple melting peaks and mixed γ and α crystal phases in the polymer solids. Since the phase behavior depends on temperature, the effect of annealing temperature, from which the copolymers were cooled, on the nonisothermal crystallization of the copolymers was also investigated. It is found that higher degree of phase separation accelerates the crystallization but reduces the crystallization enthalpy.     

FREQUENCY AND EFFICIENCY OF SOUND COLUMN AT RESONANCE

In this paper,the resonant frequency of the sound column is investigated both theoretically andexperimentally,and the efficiency of the sound column at resonant frequency is also calculated.It isshown that the resonant frequency varies linearly with the number N of the loudspeakers in the soundcolumn,and the efficiency of the sound column at resonant frequency is directly proportional to thenumber N of the loudspeakers if N≤3,and it tends to increase more slowly if N>4. We have also proved that the radiation of the loudspeakers treated in accordance with theradiation of a plane piston on the terminal of the long tube in the sound column is in fairly goodagreement with the results of the experiment.     

α PARTICLES EMITTED IN THE REACTION OF 12C ON 209Bi

The energy spectra and angular distributions of alpha particles emitted in the reaction of 12C on 209Bi in the energy range 61.1—73.0 MeV were observed.The △E— E detector system was used to separate alpha particles and other particles emitted in this reaction.The results can be interpreted in terms of the reaction mechanism,in which a 8Be cluster is transfered from the projectile to the target.Good agreement has been obtained between the cross section for the production of the direct alpha particles and that of the heavy residue 217*Fr which,left in the ground state after evaporation of 2 neutron's,decays into 211At by alpha emission.The experimental energy spectra and angular distributions have been fitted by a semi-classical formula for the differential cross section per unit solid angle and energy interval.     

THE FRAGMENTATION OF GLUON OF GLUON IN e+e－ ANNIHILATION

In this paper,we suggest that the gluon is hadronized by first splitting into a quark-anti-quark pair.The final hadrons are produced by the color interactions among the quarks and antiquarke.By this assumption,the calculated average charged particle multiplicities in e⁺e^－→3jet events,and the ratio of multiplicities between gluon and quark jet,and the rates of baryons in e⁺e^－ three gluons events all agree well with experiments.The angle distribution of final particles can be explained.     

THE RESONANCE OF THE CHAIN STRUCTURE STATES IN A(α,αx)B TYPE THREE-BODY REACTIONS

In this Paper a calculable three-body T matrix with compact kernel is obtained by using multiplier's methods. The formulations for calculating the A（a, ax）B type three-body reaction trans-tion amplitudes are presented when plane wave or distorted wave is used for the incident and outgoing states. This T matrix also includes the resonance terms of the three-body chain struc-ture states besides quasi-free scattering terms and final states interaction terms. A calculable formulation for the resonance energy of chain structure states is presented when it is expanded approximately into two two-body bound states. For ⁸Be and ⁶Li as target nuclei, the resonance energies are calculated. The results are in good agreement with the experimental values and the theoretical values of a mole-cule-like model. In order to check this kind of resonances, some experiments are proposed.     

ACOUSTICS IN INVESTIGATION OF CERAMIC MATERIALS

Ⅰ.INTRODUCTION This work presents the use of acoustic methods for investigation of ceramic materialthat is a typical example of inhomogeneous matter.Inhomogeneity is due to various crys-talline phases,the presence of glass in the structure,the appearance of grains separated byboundaries,containing large amount of inclusions and impurities,typical defects of the crystallattice and,first of all,the content of the gaseous phase.The BASIC feature of this groupof materials is the use of high-temperature firing and the tendency to prepare the techno-     

RESEARCH ACTIVITY OF ATOMIC PHYSICS IN RIKEN

RIKEN has a long trasition of atomic physics research in the field ofatomic and molecular spectroscopy.In recent years,the research activityhas also be maintained but be a little shifted to the field of spectroscopyof highly ionized ions in plasma and of high energy atomic collision ex-     

MEASUREMENT OF POWER FLOW IN VIBRATIONAL STRUCTURE

The evaluation of power flow in vibrational structure is treated theorettaly,experimentally and bycomputer simulaion.It is shown that the bending wave power can be messured with two transducers,as longas the error caused by near-field is known well.The method is very similar to the sound power measurement inair.The error caused by this way is calculated.Comparison between measured and theoretical results showsthat in thin rods the bending wave power can be calculated with the accuracy better than 2 dB.At lowfrequencies the limiting factor is the near-field influence,at high frequencies it is the transducer separation,the mass loading by the transducers and the phase difference,etc..     

ACOUSTICAL DESIGN OF HONGTA AUDITORIUM IN BEIJING

Hongta Auditorium in Beijing is a multi-purpose auditorium intended mainly for music per-formance.This auditorium with a seating capacity of 2010 persons and an effective volume of 7800 m~3was completal in 1978.It was remodlled later in order to meet the requirements for performingmusic in natural sound.The acoustics of the auditorium has been proved to be successful in theseyears. This paper mainly describes the design requirements and the concrete measures taken as wellas the formal acoustical design and evaluation.     

~(13)C CP/MAS OF MOTIONS IN SOLID POLYMERS

High-resolution 13C spectra of solid polymers are often acquired with cross polarization with magic angle spinning (CP/MAS) to take advantage of the abunda ntly available protons in the polymer chains. The sequence for transferring mag netization from 1H to13C using Hartmann-Hahn spin locking in the rotating frame is now a standard in commercial solidstate NMR spectrometers.     

COVARIANT AND QUANTIZATION OF SPINNING STRING IN Md×G SPACE-TIME

The BRS charge Q_B of BRSSS Spinning String model in M_d×G space-time is explicitly given.By means of the nilpotency of the BRS charge,the critical dimension and parameters α^R and α^NS could be fixed;and with the help of the BRS charge a BRS invariant free open BRSSS string field theory could be established.In this model,we find that supersymmetry and BRS invariance could be compatible only when the group G is abelian.And finally,the massless sector comprising gauge fields with indices of group G is demonstrated.     

CALCULATION OF THE ELASTIC-SCATTERING CROSS-SECTION OF ENERGETIC ELECTRON BY 40Ca NUCLEUS IN CONSIDERATION OF THE INFLUENCE OF“PION CONDENSATION”

Using Migdal's theoretical results of "pion Condensation", the influence of "π condensation" on the distribution of charge of N=Z nucleus is determined. The elastic-scattering differential cross-section of energetic electron by ⁴⁰Ca nucleus is also calculated. The results of our calculations agree better with the experimental data.     

THE COMBINATION RULE OF QUARKS IN e+e－ ANNIHILATION

We show that the near correlation in rapidity is consistent with the requirements of QCD, and completely determines the combination rule of quarks. We give the formulae for calculating yields of mesons, baryons and antibaryons, which are produced by a stochastic accumulation of quarks with similar rapidities. Using it to e⁺e^－ annihilation, the observation of recently unexpected copious production of baryons is explained naturally.     

INFLUENCE OF C+-IMPLANTATION DOSE ON BLUE EMISSION AND MICROSTRUCTURES OF Si-BASED POROUS β-SIC

Crystal Si were implanted with different doses of C⁺ from 10¹¹ to 10¹⁷ cm^-2 at an energy of 50 keV. β-SiC precipitates were formed by thermal annealing at 1050 ℃ for 1 h and porous structures were prepared by electrochemical anodization. Under the excitation of ultraviolet, the samples, with C⁺ dose ≥10¹⁵ cm^-2 have intense blue emission which is stronger than the photoluminescence (PL) intensity of reference porous silicon (PS), and increases as C⁺ dose increases; the samples with C⁺ dose ≤10¹⁴ cm^-2 show similar PL spectra to those of PS. The blue peak intensity in PL spectra is correlated with the TO phonon absorption strength of β-SiC in infrared absorption spectra. The transmission electron microscopy study shows that the blue peak is also correlated with the microstructures. Because porous β-SiC is nanometer in size, it is suggested that the quantum confinement effect be responsible for the blue light emission.     

STUDY OF ANGULAR DISTRIBUTION OF THE SCATTERING OF 31.2 MeV α PARTICLE BY THE NUCLEUS 10.11B

Angular distribution of the scattering of 31.2 MeV-α-particle by the nucleus ^10,11B is measured. Our results show that there is anomalous phenomenon in the case of ¹⁰B but there is not in ¹¹B. Calculations and analysis are made with the optical model adding the Regge-Pole model. The results show that for the nucleus of 1p-shell, such as α+¹⁶O, the result of the calculation agrees very well with the experimental measurements but it fails in α+¹⁰B. As to the analysis with the double v-power optieal model for α+¹⁶O, the agreement is somewhat a little worse than the former's and the result for α+¹⁰B agrees only qualitatively with the experimental measurement. It is well known that the analysis with these models for α+⁴⁰Ca agrees very well with the experimental data. Thus we may come to the conclusion that the mechanism of ALAS of the nucleus of 2s-1d shell is different from that of 1p-shell, and the mechanisms of ALAS of the nuclei of 1p-shell are also different.     

THE DETERMINATION OF ENDPOINT ENERGY FOR 235Th β-DECAY

Sources of ²³⁵Th were prepared by 14MeV neutron irradiation of Uranium and radiochemical separation.The β-spectra and γ-spectra were measured.The endpoint energy for ²³⁵Th β-decay was obtained to be 1.44±0.04MeV.Thus Q_B of ²³⁵Th was determined to be 1.47±0.07MeV.     

THE ESTIMATION OF THE PREVALENCE OF HEAR-ING-IMPAIRMENT FOR THE NOISE-EXPOSED POPULATION IN CHINA BASED ON ISO/DIS 1999.2

Based on the noise survey in China,the formula(H′=H N-HN/120 )of ISO/DIS 1999.2 ("Acous-tics-Determination of Occupational noise exposure and estimation of noise-induced hearingimpairment,1985 )was applied to the calculation of the hearing threshold level associated with age andnoise(HTLAN)of the noise-impaired people.According to the Gausscian distribution,when thenoise-exposure level L_(EX8h)was 85,90 ,95,100 dB and the hearing threshold frequency is from 0.5k to6kHz,the HTLAN of noise-exposed people withdifferent duration of exposure and its relation values tothe hearing threshold frequency associated with age(HTLA)were obtained.The ISO/DIS 1999.2 hasbeen proved to be applicable in China.     

EVOLUTIONARY SPECTRA OF BACKSCATTERING WAVE IN MOVING MEDIUM

In this paper,we discuss the backscattering wave of sonar,radar and sodar in moving medium,which is anon-stationary stochastic process even if its energy attenuation is compensated.The evolutionary spectra are agood approach to describe it,both the non-stationary factor A_t(ω) and the characteristic width B_L aresignificant.When the time interval corresponding to the volume element of the scatterers is smaller than B_L,we can suppose that the power spectrum displays a single hump characteristic,and when it is larger than B_L,we may use the power spectrum which displays a bi-hump characteristics.The transmitted signal which hasslow varing ambiguity function can reduce the effect of A_t,(ω).     

POWER EMISSION OF A MONOPOLE IN REVERBERATION CHAMBERS

An exact sound power emission formula of a simple source in a reverberation chamber is derived fromnormal mode theory as a function of its position in the room,and important properties of the emission arefound from simple analyses.For example,the average emission of the source in the room is not equal to thefree space emission but greater,on the contrary to the common notion.A smooth statistical formula is alsoderived for the variation of average sound power in an axial direction,which holds even at low frequency atwhich the wave length approaches the mean free path in the room.The sound power is found to havenumerous peaks in the room forming a three-dimensional lattice structure with high power barriers aroundthe boundary walls.The space factor in an axial direction is essentially exact,but the general formula of poweremission formed with the product of space factors in three axial directions might have some error.Numericalexamples are presented to check this.The variability of sound power emission in