Search

Article

x

Vol. 33, No. 1 (1984)

1984-01-05
CONTENT
INVESTIGATION ON NEUTRON EMISSION FROM LASER-PLASMAS
PAN CHENG-MING, ZHANG SHU-GAN, ZHU DA-QING
1984, 33 (1): 1-8. doi: 10.7498/aps.33.1
Abstract +
The characteristics of neutron emissions from leser-plasmas have been studied. Targets in the form of plane and spherical pellet were made of thermonuclear material containing deuterium, and irradiated by single beam laser system with pulse duration of the order of ns and six-beam laser systems with pulse duration of the order of ns and sns respectively.
IN-DEPTH OXYGEN CONTAMINATION PRODUCED IN CW CO2 LASER ANNEALED Si
XU ZHEN-JIA, CHEN WEI-DE
1984, 33 (1): 9-15. doi: 10.7498/aps.33.9
Abstract +
Siwafers annealed by CW-CO2 laser have been studied using Nomarski technique, electron absorption image, IR spectrum, AES and ESCA, with particular emphasis on the study of in-depth oxygen contamination. Electron absorption image shows that the effect of CW-CO2 laser annealing is not very uniform in our case. And it has also shown that CW-CO2 laser annealing in air would decrease the carbon contamination on the Si surface, but produce oxygen contamination. This oxygen contamination consists of two parts: SiOx on the surface and free oxygen atom underneath, its thickness is less than~250?.
STUDY OF TWO-PHOTON OPTICAL BISTABILITY
ZHU SHI-YAO
1984, 33 (1): 16-24. doi: 10.7498/aps.33.16
Abstract +
By using quantum method and decorrelation approximation, the twophoton bistability equation in three level atom medium is obtained. The conclusions are consistent with experiment results. The shortcomings in treating this problem by using two-photon vecter model are pointed out.
RENORMALIZED QUASI-LINEAR THEORY OF TURBULENCE IN NON-UNIFORM PLASMA——GENERALIZATION OF MISGUICH-BALESCU THEORY
QIN YUN-WEN
1984, 33 (1): 25-36. doi: 10.7498/aps.33.25
Abstract +
The re-normalized quasi-linear theory of turbulence in uniform plasma, given by Mis-guich and Balescu, is generalized to the case of non-uniform plasma. In the weak-coupling and the weak non-uniformity approximation, the explicit expressions for the propagator and the average turbulent collision operator are obtained. Non-uniformity not only modifies the diffusion contribution, resonance broadening or frequency shift, Dupree damping and velocity-space slope effect of the average distribution function in these operators, but also producesnew differentio-exponential operators——the velocity differential operator in the propagatordue to non-uniformity of the time-space correlation function, and the space differential operator in the average turbulent collision operator due to non-uniformity of the average distribution function. Non-uniformity of the average distribution function prevents two free-stream propagators that are inverse to each other in the expression for the average turbulent collision operator in terms of the propagators from compensating for each other, and as a result the non-Markovian contribution in the propagator acted immediately on the average distribution function appears.
ABSOLUTE PARAMETRIC INSTABILITIES WITH TWO LINEAR TURNING POINTS
CHEN LIU, ZHOU YU-MEI, ZHANG CHUN-YUAN, SHEN JIE-WU, CAI SHI-DONG
1984, 33 (1): 37-46. doi: 10.7498/aps.33.37
Abstract +
We show that, in weakly inhomogeneous plasmas, there exist absolute parametric instabilities if each of the two decay waves has a linear turning point and the two turning points are of the same sign. Corresponding expressions for the threshold condition and growth rate are also obstained in analytical form, they agree very well with numerical results.
MEASURING ELECTRON CYCLOTRON RADIATION FROM PLASMAS BY MEANS OF CONFOCAL RESONANTOR
WANG ZHAO-SHEN, WANG YA-MIN
1984, 33 (1): 47-52. doi: 10.7498/aps.33.47
Abstract +
A method of measuring the electron cyclotron radiation from plasmas by using confocal resonant cavity and sweep frequency receiver is proposed. A radiation spectrum expression for a uniform plasma slab in the confocal resonant cavity has been derived. The analysis shows this method can independently measure TOKAMAK's electron temperature and its radial distribution. Furthermore, as a quasi-optical receiving system, it possesses high spatial resolution power.
15N NUCLEAR RESONANCE REACTION AND HYDROGEN PROFILE IN PALLADIUM
WANG GUANG-HOU
1984, 33 (1): 53-57. doi: 10.7498/aps.33.53
Abstract +
The 15N+ 1H→12C+4He+4.43MeV(γ-ray) nuclear resonance reaction has been used to study the H concentration versus depth in Pd. It is a precise method because. (1) it has a high depth resolution (~50?); (2) γ-ray can be detected easily after penetrating low temperature and vacuum systems; (3)the isolated resonance has an energy of 6.385 -MeV with very narrow width (6-keV); (4) it has reaction cross section of 0.46 barn and high sensitivity. In this paper, the principle of the method, the experimental set-ups as well as hydrogen distribution in the superconducting Pd (H) prepared at different conditions are discussed. In comparison with the observations on the presure charged sample, some new ideas about the hydrogen behavior in this kind of superconductor are given.
THE STEP STRUCTURE EFFECT OF DC JOSEPHSON CURRENT WITHIN ONE FLUX QUANTUM PERIOD (Ⅰ)——SQUID CONSISTING OF TWO JUNCTIONS
ZHENG JIE-FEI, ZHANG YU-HENG, LI YU-ZHI
1984, 33 (1): 58-68. doi: 10.7498/aps.33.58
Abstract +
If a SQUID consisting of two junctions is placed in a cavity with sufficiently high Q-value, when the Josephson frequency of the junction ω=2eV0/h equals to one of the ei-gen frequencies ωr of the cavity, then the oscillating electromagnetic field in the form of standing wave excited by the junction current would react on the junctions and produce a series of steps of dc Josephson current within one flux quantum period Φ0. The theory also predicts that a series of new superconducting quantum interference phe-nomenons would be produced by Josephson currents of two junctions in the feed back field. The step height of the Josephson current will be inreased when both junctions are placed separately at the peak of the standing wave. The phase of the interference trace of SQUID will change by π/2 when one of the junctions is placed at the peak and the other is placed at the trough. The I-H trace of SQUID will degenerate to that of signle junction when one of the junctions is placed at the pack and the other is placed at the node. The step will not occur except that with n=0 yhen both junctions are placed separately at nodes.
FURTHER STUDIES ON THE PHASE TRANSITION OF LITHIUM IODATE (LiIO3) POLYMORPHISM
LIANG JING-KUI, ZHANG YU-MING
1984, 33 (1): 69-75. doi: 10.7498/aps.33.69
Abstract +
Further studies on the phase transition mechanism of LiIO3 at normal pressure have been made by means of DTA, heat-treatment, and powder X-ray diffraction. There are three phases of LiIO3, β,η,δ, existing relatively stably at high temperatures and they can directly melt respectively. Their melting points are as follows: phase β, 432℃; phase η, 421℃; phase δ, 416℃. The melting points, thermal processes and the exiting temperature ranges ail show that the order of their thermodynamical stability is: β>η>δ. In dry air and at room temperature, the phase ζ of LiIO3, which changes to phase β when it is heated to 335℃ at 10℃/min, stands long periods of time without any change as well as phase α and β . In the existing temperature range of α -LiIO3, phase ζ does not transform into phase α although it is heat-treated for a long time. The temperature of phase transition of ζ to β is higher than that of α to β. The existence of phase β in the phase ζ has a promotive effect on the phase transition of ζ to β just as the case of α to β. The existence of phase ζ in the phase α has also a promotive effect on α to β . The phase θ, like the phase γ. is also an intermediate metastable phase in the phase transition processes of LiIO3.
PHASE EQUILIBRIUM RELATION OF BaB2O4-Li2B2O4 AND BaB2O4-Li2O SECTIONS IN THE TERNARY SYSTEM BaO-Li2O-B2O3
HUANG QING-ZHEN, WANG GUO-FU, LIANG JING-KUI
1984, 33 (1): 76-85. doi: 10.7498/aps.33.76
Abstract +
The pseudo-binary systems BaB2O4-Li2B2O4 and BaB2O4-Li2O in ternay system BaO-Li2O-B2O3 have been studied by means of X-ray diffraction and thermal -analysis. A new compound 4BaB2O4 ·Li2B2O4 which is formed by peritectic reaction at 930 ± 3℃ has been discovered in the BaB2O4-Li2B2O4 system. There is a eutectic horizontal from 4BaB2O4 ·Li2B2O4 to Li2B2O4 at 797±3℃ with a eutectic point component of 79 mol% Li2B2O4. In BaB2O4-Li2O system, there also exists a compound of 4BaB2O4 ·Li2B2O4, formed by peritectic reaction. But its peritectic reaction temperature dropped to 908±3℃ with increasing amount of Li2O. Another new compound 2BaB2O4 ·3Li2O is formed by peritectic reaction at 630±3℃ and eutectic reaction occur from 2BaB2O4 ·3Li2O to Li2O at 400±3℃ and from 2BaB2O4 ·3Li2O to Li2CO3 at 612±3℃. No solid solution is observed in BaB2O4-Li2B2O4 and BaB2O4-Li2O systems.The X-ray powder diffraction pattens of 4BaB2O4 ·Li2B2O4 and 2BaB2O4 ·3Li2O have been indexed by computed programme. It is shown that the space group of 4BaB2O4·Li2B2O4 is Pmma with lattice parameters α = 13.033?, b=14.630?, c = 4.247?. There are two formula units per unit cell. The space group of 2BaB2O4 ·3Li2O is Pmmm. Lattice parameters are α = 4.814?, b = 9.897?, c=11.523?. There are two formula units per unit cell.
BRIEF REPORT
YOUNG TABLEAUX FORMS OF FN CONFIGURATION WAVE FUNCTION
ZHANG SI-YUAN
1984, 33 (1): 86-92. doi: 10.7498/aps.33.86
Abstract +
By using the Young tableaux, a systematic method of expressing the wave function of fN configuration spectral term, in particular, the wave function of degenerate spectral term, are given. The wave functions obtained are in accordance with the Racah group chain.
STATISTICAL THEORY OF DEFECTS AND INPURITIES IN AMORPHOUS SEMICONDUCTORS
CHEN GUANG-HUA, LIU HUI-CHUN
1984, 33 (1): 93-98. doi: 10.7498/aps.33.93
Abstract +
This article discusses doping effects in amorphous semiconductors, especially the properties at low temperatures, using the method of statistical physics. With approximation of single dangling bond, the positions of Fermi level and the electron densities have been calculated for two groups of amorphous semiconductors.
CALCULATION OF THE ELECTRON-PHONON COUPLING S FACTOR INDUCED BY RARE-EARTH IMPURITIES IN CRYSTALS
GU ZONG-QUAN, WANG YONG-LIAN
1984, 33 (1): 99-104. doi: 10.7498/aps.33.99
Abstract +
A formula is given for calculating minimum electron-phonon coupling S factor in mul-tiphonon transitions, this formula has the advantage of being independent of lattice vibration modes. The S factors have been evaluated for the multiphonon transitions among the multiplets 5F1,5F4,5F5,5G4,5G5 of Ho3+ ion in the LaF3 crystal. The values obtained for the S factor are around 0.05, which is in agreement with experimental results.
THE INFLUENCE OF PHOTO-INDUCED REFRACTIVE INDEX CHANGE ON RAMAN SPECTRA OF LiNbO3: Fe CRYSTALS
LIU SI-MIN, ZHANG GUANG-YIN, WU ZHONG-KANG, LI GUAN-GAO, FENG SHANG-TING, ZHANG JIA-MIN, ZHAO JIA-NAI, XU LIANG-YING
1984, 33 (1): 105-109. doi: 10.7498/aps.33.105
Abstract +
Obvious anomalous phenomenon in Raman spectrum of LiNbO3:Fe crystals for some scattering geometry has been observed. The phenomenon is associated with the anomalous light scattering process occured after photo-induced refractive index change in crystals.
CALCULATION OF ZERO FIELD SPLITTING PARAMETERS OF 3d5 IONS IN LOW SYMMETRY CRYSTAL FIELD
YANG GUI-LIN, XU YOU, ZHAI HONG-RU, DUAN MING-QIAN
1984, 33 (1): 110-115. doi: 10.7498/aps.33.110
Abstract +
As a natural extension of work [4], in this paper the calculation of zero field splitting parameter D of 3d5 ions in low symmetry ( C4v or D4h,C3v or D3h ) crystal field is discussed. The expressions of parameter D in terms of Racah parameters, crystal field parameters and spin-orbit coupling constant ξ are obtained. Applying to Fe3+ in α -Al2O3 crystal, the calculated result agrees fairly well with the experimental value.
OPTICAL PUMPING OF 87Rb ATOMS USING 85Rb LAMP
YANG FENG, LIU SHU-QIN, DONG TAI-QIAN
1984, 33 (1): 116-120. doi: 10.7498/aps.33.116
Abstract +
An optical pumping device, consisting of only 85Rb lamp and 87Rb absorption bulb, is used. The 0-0 transition resonance signal of 87Rb ground state is found to be greater than that in the conventional optical pumping device, in which the 87Rb lamp, 85Rb filter and 87Rb absorption bulb are used. In a definite temperature range, a negative resonance signal is observed. Up to now, it has not been explained yet. The line-width and optical frequency shift are measured. The possibility of applying this device in 87Rb atomic frequency standard is discussed.
A COMMENT ON THE REASONS FOR THE FAILURE OF MULTAN
YAO JIA-XING
1984, 33 (1): 121-125. doi: 10.7498/aps.33.121
Abstract +
MULTAN-multisolution tangent formula procedure is based on the probability distribution of three phase invariants. Based on this distribution, we analyzed how a small starting set, the main weakness of MULTAN, effects the process of phase development and refinement by the tangent formula. The reason of MULTAN failure and the approach to overcome the disadvantage of small starting set are discussed here. The principle and advantage of RANTAN-random MULTAN is elucidated briefly and compared with MULTAN in fourexamples.
CALCULATION OF RELATIVISTIC ENERGY LEVELS OF HYDROGEN ATOM BY SPINOR METHOD
XU DIAN-YAN
1984, 33 (1): 126-131. doi: 10.7498/aps.33.126
Abstract +
In this paper, the relativistic wave equation of hydrogen atom is studied in spinor formalism. The energy formula derived is the same as that derived by Γ -matrix method, but the commutation relation is not explicitly used in the calculation.
A MOSSBAUER INVESTIGATION OF THE IRON-SODIUM-SILICATE GLASS SYSTEMS
XIA YUAN-FU, LIU RONG-CHUAN, WANG SHU-XIN, XU CHAO, PAN SHU-YING, CHENG YI-BING
1984, 33 (1): 132-136. doi: 10.7498/aps.33.132
Abstract +
Mossbauer absorption measurements have been made at room temperature on 57Fe in Na2O-Fe2O3-SiO2 and Na2O-Fe2O3-SiO2-B2O3 systems. The states of the ferrous and ferric ions have been studied on the basis of Mossbauer parameters. A basic model of the iron in these glass systems is then proposed.
LETTERS
REPORT ON A NONSYMMETRICAL DOUBLE-CORE EVENT
WANG CHENG-RUI, CAO PEI-YUAN, LI JIN-YU, REN JING-RU, LU SUI-LING, KUANG HAO-HUAI, SU SHI, WANG YUN-XIN, WANG DIAN-CHEN, XUE YONG-GUI, LI GUANG-JU, LIU JIAN-GUO, GENG QING-XI
1984, 33 (1): 137-139. doi: 10.7498/aps.33.137
Abstract +
A double core event with ∑Er≈1000 TeV, observed in MEC, is reported. The distributions of particles in the two cores are quite dissimilar from each other. The event is briefly discussed.
REPORT ON A SUPERHIGH ENERGY HADRONIC EVENT WITH SEVERAL HIGH PT COMPONENTS
WANG CHENG-RUI, CAO PEI-YUAN, LI JIN-YU, REN JING-RU, KUANG HAO-HUAI, HUO AN-XIAN, LU SUI-JING, SU SHI, WANG DIAN-CHN, HU WEN-JUN, FAN HAI-KUEN, LI GUANG-JU
1984, 33 (1): 140-142. doi: 10.7498/aps.33.140
Abstract +
An analysis of the gamma-ray family(∑Er≈1300 TeV) obtained with emulsion chambers at Mt. Kambala was made. The event is produced by one nuclear interaction occurred at an altitude less than ~150 m above the chamber. The central region of the event is composed of 5 clusters. The characteristics of the event is discussed.