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.     

DISCUSSION ON THE RELATIONSHIP BETWEEN THE FREQUENCIES OF INJECTOR LINAC AND e+e－ STORAGE RING

The question of the relationship between the frequencies of injector linac and storage ring is analysed, especially when sub-harmonic buncher is used. In that case, it seems to be necessary to keep the ratio of two frequencies of the linac and storage ring to be an integer. This question is discussed in detail in this paper from several points of view. As a result of the discussion, two suggestions to avoid the restriction on the frequency relationship are presented.     

ON THE COULOMB DISINTEGRATIONS OF ATOMS （e+e-） AND （μ+μ-）

The cross sections and energy spectra of the Coulomb disintegration of （e⁺e^-） and（μ⁺μ^-）at high energies are calculated by using the perturbation expansion of com-posite field theory [1] and the approximate covariant solution to Bethe-salpeter equa-tion with Coulomb potential and spin 1/2, -1/2^[2] . The cross sections of disintegrationof （e⁺t^-） are about 20% less than the cross sections calculated by others [3]. Be-sides; the results obtained in this paper indicate that the cross sections of coulomb di-sintegration of （e⁺e^-） or （μ⁺μ^-） at high energies in singlet state and triplet stateare equal exactly, while in [3] this oicurs only when n=2, and when n=1 the dif-ferenles betwees the rross sections in the two states are about 25%. It is very likelythat there were some mistakes in these calculutions.     

Kei2 ECR离子源C4+、C5+束流的最佳结果

With the prototype ECR ion source for the next carbon therapy facility in Japan a new series of measurements has been performed in order(a)to find the highest beam currents of C~(4 ) ions,and(b)to study the effect of"special"gas-mixing by using a chemical compound as a feed gas.An isotopic effect has been found in a previous experiment:with deuterated methane(CD_4 gas) the C~(5 ) beam currents are about 10% higher than with regular methane(CH_4 gas).For butane gases(C_4D_(10) and C_4H_(10) respectively)the isotopic effect for C~(5 ) production is even stronger(>15%).For production of C~(4 ) ions the isotopic effect appears to be absent.It turns out that the relative amount of carbon is much more important:acetylene gives 15% higher C~(4 ) current than butane,which in turn gives about 10% higher C~(4 ) ion currents than methane.     

DEPENDENCE OF THE MECHANISM AND CROSS SECTION OF THE α PARTICLES EMITTED FROM 12C+64Ni REACTION ON INCIDENT ENERGY

Energy spectra and angular distributions of the particles emitted from ¹²C+⁶⁴Ni reaction at eight energies in the region of 36.5MeV—69.4MeV are measured. The angular distributions of α particles change from forward peaked one to that peaked near by the grazing angle with decreasing incident energy. This result show that the emission mechanism of non-evaporation α particle is different in different energy regions.     

C+2离子轰击聚乙烯合成C26晶体

C     

INFLUENCE OF γ-RADIATION ON THE DIELECTRIC CHARACTERISTICS IN Rb2ZnCl4 SINGLE CRYSTALS AT INCOMMENSURATE-COMMENSURATE PHASE TRANSITION

In this paper the influence of γ-radiation on the dielectric constants of Rb₂ZnCl₄ crystal at incommensurate-commensurate phase transition (hereafter abbreviated as INC-C transition) are studied. The thermal hysteresis occurs upon both cooling and heating runs, irrespective of whether the samples have been treated with γ-radiation or not. For the γ-irradiated sample, its transition point, T_c, between the INC and C phases is not changed, but the peak value of the dielectric constant at T_c increases abruptly, compared with that before γ-irradiation, When this sample is annealed at 40℃, the peak value restores to the incipient value for the sample free from γ-irradiation. The origin of the phenomenon of the thermal hysteresis of the dielectric constant may be due to the pinning effect of dejects or impurities in the samples.     

THE DOUBLE SPECTRAL FUNCTIONS OF PHOTON-NUCLEON SCATTERING AND INELASTIC CROSS-SECTIONS OF γ+p→p+π++π-

Using elastic unitary condition of t channel, the double spectral function of photon-nucleon scattering and absorbtive parts of scattering amplitude (s channel) are given. Using date of low energy πN(3,3) resonance ρ resonance, the photo-production cross-sections of γ+q+q+π⁺+π- are calculated. The results are compared with the recent experimental data.     

FISSION MEASUREMENT ON 5.5 TO 21.7MeV/A 28Si+197Au SYSTEM (Ⅱ) ANGULAR DISTRIBUTION OF ICF AND SF

According to the distribution of linear momentum transfer (lmt) obtained from the correlation measurement of fission partner,the events of Incomplete Fusion Fission (ICF) and Sequential Fission (SF) were distinguished.The fission angular distributions of both ICF and SF were obtained,respectively.
With calculating the moment of inertia by Cassinian Ovaloid as the fission shape, the angular distributions were fitted by current procedure.The spins of fission nuclei corresponding to ICF and SF are extracted.The relation between spins and bombarding energy is discussed.Besides,the angular distribution in coincidence with complex particles is discussed.     

EFFECTIVE POTENTIAL OF λφ41+3 AT ZERO AND FINITE TEMPERATURES

The effective potential of λφ⁴₁₊₃ model with both signs of parameter m² is evaluated at T=0 by means of a simple but effective method for regularization and renormalization. Then at T≠0, the effective potential is evaluated in imaginary time Green function approach, using the Plana formula. A critical temperature for restoration of symmetry breaking in the standard model of particle physics is estimated to be T_c≌510 GeV.     

COINCIDENCE MEASUREMENT BETWEEN α-PARTICLES AND PROJECTILE-LIKE FRAGMENTS IN REACTION OF 82.7MeV 16O ON 27Al

In the coincidence measurement between α-particles and projectile-like fragments in the reaction of 82.7MeV ¹⁶O on ²⁷Al,the contour plot of the C-α coincidence in the velocity plane and the coincident angular correlation are obtained. Different mechanisms of α-particle emission are analysed. A possible reaction mechanism of incomplete DIC is descussed.     

ON THE “DIRECT CHANNEL DIAGRAM” OF THE PRODUCTION OF THE （π+ π-）s S-STATE ATOMS

In this paper we work out the relativistic covariant B-S wave function for the（π⁺ π^-）_s atoms.Some properties of the“direct channel diagram”of the produc-tion the （π⁺ π^-）_s atoms are discussed by calculating the cross-section of the process π⁺ +n→p+（π⁺ π^-）_s with the help of the relativistic covariant wave function and assuming the lowest termin the perturbation expansion series of the quantized composite field theory——the“direct channel diagram”is dominant.Besides this calcuation perhaps presentsa rough estimate for the interesting process μ⁺ +n→（μ⁺ π^-）+p.     

MEASUREMENT AND ANALYSIS OF EMITTED α PARTICLES IN REACTIONS OF 12C BOMBARDING 12C,27Al AND natCa

The energy spectra and angular distributions of the emitted α particles in the reactions of the 69.5MeV ¹²C bombarding ¹²C,²⁷Al and ^natCa have been measured and analysed using the fast particle exciton model. The contribution from the equilibrium and preequilibrium α-emissions is calculated to be 89%, 81% and 83% of the total α yields for the three reactions respectively, where the preequilibrium α emissions are 11%, 14% and 16% respectively. A small contribution comes from the other reaction mechanism.     

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.     

HT-6M托卡马克C6+离子的径向分布

利用光学多道分析仪测量了HT-6M托卡马克CⅥ（207.1nm）谱线线形分布．结果表明CⅥ谱线来源于电荷交换复合辐射．根据对CⅥ谱线时间行为的测量，进一步证明了这一结果，并推算出完全剥离C⁶⁺离子的径向分布． 关键词：     

ELECTRONIC STRUCTURE OF Hg0.8Pb0.2Ba2Ca2Cu3O8+δ: THE ROLE OF Pb DOPING, OXYGEN DOPING AND HIGH PRESSURE

The effects of Pb doping, oxygen doping (δ= 0.1,0.2,0.4 and 0.5) and high pressate (4, 8, 15 and 20GPa) on the electronic structure of Hg_0.8Pb_0.2Ba₂Ca₂Cu₃O_8+δ have been examined by the recursion method. Our calculations show that Pb doping only decreases the hole concentration slightly and oxygen doping increases the hole concentration monotonically and significantly as δ varies from 0 to 0.5, with each excess oxygen atom contributing about 1.7 holes to the CuO₂ layers. The optimal δ is estimated to be around 0.4, The hole conceatration increases initially with pres-sure but decreases as P > 8GPa (i.e., dn/dP does change sign at ～ 8GPa). The suppressed T_c(P) by Pb substitution has to be described in the modified Neumeier's model.     

SEMI-INCL USIVE DISTRIBUTIONS AND RAPIDITY DEPENDENCE OF MULTIPLICITY DISTRIBUTIONS IN e+e－ ANNIHILATION INTO TWO JETS

In this paper,the rapidity distribution of quarks is further assumed to be a uniform distribution with the constraint of four momentum conservation.We apply Monte Carlo approaches to light quark jets.The semi-inclusive distributions and the multiplicity distributions in rapidity intervals are calculated.The characteristics of these distributions are discussed and the results are compared with the experimental data of average jets.     

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.     

THE STUDY OF α-EMISSION INDUCED BY 16O ON 27Al

The α-particles induced by 84.5MeV and 62 MeV ¹⁶O on ²⁷Al are measured using ΔE-E semiconductor telescope. The energy spectra, the angular distributions, the contour plot of d²σ/dE﹒dΩ in the E-θ plane of the emitted α particles and the variation of the nuclear temperature with the emission angles are obtained. The mechanism of the direct α particles is discussed.     

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.