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Vol. 32, No. 4 (1983)

1983-02-20
CONTENT
CALCULATION OF PROJECT ION-RANGE DISTRIBUTION MOMENTS IN COMPOUNDS AND ALLOYS (I)——RANGE DISTRIBUTION MOMENTS FOR HEAVY IONS (Z1>10)
Yang Hong, Xia Yue-yuan, Tan Chun-yu, Li Jin-hua
1983, 32 (4): 423-445. doi: 10.7498/aps.32.423
Abstract +
Project range and range distribution moments up to third order for twelve ion species implanted into five different substrates (such as amorphous A12O3, SiO2, UO2, LiNbO3 and 20/25/Nb stainless steel) are calculated using an improved nuclear scattering function developed recently. Some results are given for the ions considered with energy range from 5 keV to 1 MeV. The present theoretical results are compared with those published by Gibbons et al. and Winterbon, and our results are proved to agree with the recent experimental measurements more closely. The calculation method which deals with the range distribution moments in amorphous compounds and alloys is presented in some detail, and a brief discussion on the calculation accuracy is given.
A STUDY ON THE SUPERCONDUCTIVITY OF FAST QUENCHED Al-Si-Ge ALLOY
Chen Xi-chen, Guan Wei-yan, Yi Sun-sheng, Wang Zu-lun, Lin Ying
1983, 32 (4): 446-459. doi: 10.7498/aps.32.446
Abstract +
The effect of heat treatment on the microstructure and superconducting properties of the alloy Al-8.3 at% Si-8.5 at% Ge prepared by the splat quenching technique has been studied. The results of structure analyses indicate that the rapidly cooled alloy consists of two phases: a supersaturated α-Al (Si, Ge) solid solution (matrix) and amorphous Al-Si-Ge spheres, these spheres connect with each other and form a continuous canal. After annealing at 100℃ for 50 h., the spheres decrease in size and the continuous canal disappear and some dispersive Si (Ge) granules separate out from the amorphous phase. Two superconducting-normal transitions have been found in the resistance-temperature and resistance-magnetic feild curves of the sample after annealing at 100℃ for 50 h. These results can be interpreted by the existence of two superconducting phases in this sample.
THE APPLICATION OF MICRO-AREA X-RAY ENERGY DISPERSIVE ANALYSIS IN INVESTIGATING BARIUM-RARE EARTH FLUOROCARBONATE MINERALS
Wang Yi-hua, Zhang Pei-shan, Li Fang-hua, Fan Han-jie
1983, 32 (4): 460-465. doi: 10.7498/aps.32.460
Abstract +
A simple qnantitative method for X-ray energy dispersive analysis in investigating barium-rare earth fluorocarbonate minerals has been proposed. The reliability of this method has been tested. It is pointed out that the method might be useful in discovering new members belonging to this series of minerals.
EFFECT OF H+ ON THE β→α TRANSITION IN β-LiIO3 AFTER HIGH PRESSURE TREATMENT
He Shou-an, Zhao You-xiang, Liu Jia-rui, Li Yin-yuan
1983, 32 (4): 466-472. doi: 10.7498/aps.32.466
Abstract +
Using the X-ray diffraction method, we have investigated the effects of high pressure and H+ impregnation on β→α transition in β-LiIO3 crystals. The samples had been subjected to high pressure treatment (up to 80kb)at room temperature and then preserved in ordinary environmental condition for different periods of time. The experimental results show that in β→α transition in the samples treated as above the pressure can be understood to play a role of promoting the nucleation of a -phase in β-matrix, and the pressure dependence of the rate of nucleation N can be expressed in the form of N ∝ekp (k= 26.8/bar). The significant increase of quantity of α-phase in such samples may be attributed to the rapid growth of α-LiIO3 nucleus under the influenle of H+ formed through the dissociation of adsorped water molecules on the surface of a nucleus. This conclusion is supported by the similar effects in the experiment of H+ impregnation of pressurized β-LiIO3 samples.
GROWTH AND PROPERTIES OF LARGE LiNbO3 CRYSTALS
Liu Jin-long, Li Hui-zhang, Shi Zhong-jian, Yang Yin-lan, Weng Wen-sheng
1983, 32 (4): 473-480. doi: 10.7498/aps.32.473
Abstract +
With pulling direction along [0001] axis and normal of (1014) plane, respectively, growth of large LiNbO3 single crystals was achieved by using Czochraski technique. The dimension of the crystals was 100 mm in diameter and 50 mm long. Measurements of various properties were made. The quality of these crystals was found to be uniform. Thieir piezo-elastic-dielectric properties were the same as ordinary LiNbO3 single crystals.
STIMULATED BRILLOUIN SCATTERING DUE TO LASER-PLASMA INTERACTIONS
Xu Zhi-zhan, Yin Guang-yu, Zhang Yan-zhen, Lin Kang-chun
1983, 32 (4): 481-489. doi: 10.7498/aps.32.481
Abstract +
Our investigation indicates that if the incident laser contains distinct pre-pulse, the occurrence of stimulated Brillouin scattering under the interaction of high intensity sub-ns pulse laser with plasmas can be self-consistently confirmed. The evidences include an anomalous increase of the fraction of incident laser energy which is backscattered into the focusing lens, the red shift and broadening of spectrum of back-reflected laser, the dramatic reduction of total ion energy and fast ion emission, the enhancement of sidescattered laser light at large scattering angles and so on.
NORMAL-MODE SOUND FIELD OF DIRECTIONAL RADIATOR
Zhang Ren-he, Zhu Bai-xian
1983, 32 (4): 490-496. doi: 10.7498/aps.32.490
Abstract +
In this paper, the sound field of a more general directional radiator in a stratified medium is treated, and the concept of directivity is applied to calculation of the normal modes. The result shows that the normal-mode field of a directional radiator can be obtained by supplementing the normal-mode expression of a omnidirectional point source with the directivity-excitation-function, which is dependent on the position and directivity of the radiator. In addition, the normal-mode fields of the radiators with vertical-symmetrical, vertical-antisymmetrical, single-side and sharp directivity are calculated, respectively.For the vertical line array in a homogeneous water-layer, if the source distribution is proportional to the eigenfunction of some normal mode, the zeros of the directivity-excitation-function are just corresponding to the directions of eigen-rays of other normal modes.
THE RECOMBINATION BEHAVIOR OF PLATIUM IN SILICON
Zhou Jie, Li Shu-ying, Tan Fei
1983, 32 (4): 497-506. doi: 10.7498/aps.32.497
Abstract +
With dark capacitance transient method, electron emission and capture transient processes at deep level, which is located within an energy range of KT above EF in depteled region of zero-biased junction, have been observed in Pt diffused deep diffsion junction of n-Si and p-Si with different background doping density. These transient behaviors agree with the solution of electron variation rate equation of deep level for different initial conditions at that place.In this paper, a machanism is also proposed to explain the occurrence of emission transient. It is considered that the origin of emission transient is closely related to the structure in the deep diffusion junctions and the capture transient to the capture characteristic of different impurity.
BRIEF REPORT
TOKAMAK-LIKE EQUILIBRIA OF RELATIVISTIC ELECTRON BEAMS
Shi Bing-ren
1983, 32 (4): 507-514. doi: 10.7498/aps.32.507
Abstract +
The toroidal equilibrium properties of relativistic electron beams with double- δ function distribution are considered. The approximate solutions of the magnetic flux and the electric potential equations expanded in terms of the inverse aspect ratio of the torus are obtained analytically. The drift surfaces of electrons in the beam are also described.
LOCALISATION OF ENERGY IN GENERAL RELATIVITY
Liu Wen-sen
1983, 32 (4): 515-519. doi: 10.7498/aps.32.515
Abstract +
The main statements of paper [1] are critically reviewed and the blunders in the deduction are indicated. It is showend that the total energy-momentum complex proposed in paper [1] and the energy of gravitational field in a finite part of space are not unique under pure spatial transformation and, therefore, are not possessed of a definite physical meaning.
DETERMINATION OF THE DISPERSION AND THE MEASURE-MENT OF THE THICKNESS OF EPITAXIAL GARNET FILMS
Wang Li-xuan
1983, 32 (4): 520-524. doi: 10.7498/aps.32.520
Abstract +
A technique is proposed for determining the dispersion and measureing the thickness of epitaxial garnet films. Use is made fully of the transmission spectrum obtained by spe-ctrophotometer. When the wave length is greater than 2μm so that the absorption and dispersion become negligible, the refractive index at the corresponding wave length may be calculated from the extrema of the transmittance. According to the condition of in-terferrence, the order of interferrence is calculated and deduced for all interferrence extrema. The refractive indices of the film at the wave lengths corresponding to the interferrence extrema may be calculated. Finally the coefficience of Cauchy's dispersion formula are evaluated by the method of least squares, thus the dispersion relation is obtained for this film. Then, in making use of the dispersion relation, the thickness of the film may be calculated.
THE Li SITES IN THE RT AND LOW TEMPERATURE PHASES OF LiKSO4 CRYSTALS
Meng Qing-an, Cao Qi-juan
1983, 32 (4): 525-529. doi: 10.7498/aps.32.525
Abstract +
A structural phase transition in crystal LiKSO4 at Tc = 195 K was confirmed by NMR experiment previously. In this article, the temperature dependence of the electric field gradient tensor at lithium site in the range of 110-300 K is reported, and combined with a simplified ion crystal model the crystal structure is discussed. It is shown that even in the room temperature phase, the lithium position should be at (2/3, 1/3, 0.706) instead of the position at (2/3, 1/3, 0.849) suggested previously by Bradley. The phase transition is attributed to the displacement of lithium ions. The space group of the low temperature phase may be R3.
ANOMALOUS AMPLITUDE-DEPENDENCE EFFECT OBSERVED IN Al-0.5wt% Cu ALLOY WHEN THE INTERNAL FRICTION IS EXTREMELY LOW
Ge Ting-sui, Pan Zheng liang, Zhang Jin-xiu
1983, 32 (4): 530-533. doi: 10.7498/aps.32.530
Abstract +
Free decay curves of slightly cold-worked Al-0.5 wt% Cu specimen aged at room temperature (20℃) for 24 hrs were determined by an automatic inverted torsion pendulum with computer control. A series of amplitude internal friction peaks were observed as the excitation amplitude was increased succestively even when the internal friction was very low.
THE RESEARCH OF SUPERCONDUCTIVITY IN THE Ti-Pd SYSTEM
Luo Qi-guang, Jin Duo, Liu Zhi-yi, Ran Qi-ze, Jin Zuo-wen, Ma Ming-rong, Zhao Zhong-xian, Ni Yong-ming
1983, 32 (4): 534-538. doi: 10.7498/aps.32.534
Abstract +
This paper gives the relationship between the superconductive critical temperature and the composition of the alloys in Ti-Pd system, and discusses it in connection with the Ti-Pd phase diagram. It is pointed out that the superconductivity in the Ti-Pd system is due to the contribution of the titanium-palladium solid solution. It is also suggested that the limit of the palladium solubility in Ti-Pd system should be relatively large.
MECHANISM OF THE “SPILLOVER” OF RAMAN SPECTRAL LINES AND THE CHANGE OF THEIR INTENSITIES IN α-LiIO3 SINGLE CRYSTAL UNDER THE ACTION OF A DC FIELD
Yang Hua-guang, Li Chen-xi, Xu Zheng-yi
1983, 32 (4): 539-543. doi: 10.7498/aps.32.539
Abstract +
The "spillover" of the Raman spectral lines and the change of their intensities were observed in a- LiIO3 single crystal under the action of a DC field. They are due to the fluctuation of the polarizability tensor and the Raman tensor of α-LiIO3 single crystal during the transportation of ions. The former induces the o←→e scattering. Sequently, if this o←→e scattering light acts as an incident beam to produce Raman scattering, the phenomena mentioned above could occur. The latter brings about the phenomena directly. The former mechanism is predominant.
EXPERIMENTAL OBSERVATION ON 3/2ω0 HARMONIC EMISSION FROM LASER PLASMA
Chen Shi-sheng, Zhao Qin-chun, Bi Wu-ji, Wang Xiao-qin, He Xing-fa
1983, 32 (4): 544-547. doi: 10.7498/aps.32.544
Abstract +
The measurment on the 3/2ω0. harmonic emission from laser plasma has been carried out. The experimental results show that harmonic spectra has a blue-shift of about 70? and is broadened by about 26? when power density on the target surface is about 1014W/cm2. There is a slight broadening of spectra following the increase of power density on the target surface.
MEASUREMENT OF DISCHARGE CIRCUIT DISTRIBUTIVE INDUCTANCE FOR BLUMLEIN EXCIMER LASER
Chen Jian-wen, Xia Kang-min, Liu Miao-hong, Zhong Fan
1983, 32 (4): 548-552. doi: 10.7498/aps.32.548
Abstract +
Technique on measuring discharge current of Blumlein circuit using magnet-light method is described briefly in this paper. The more exact method estimating distributive inductance of discharge circuit is presented. The circuit equations are solved and the analytic expression of distributive inductance is derived. Finally, the calculated result is discussed.
THE MOLECULAR AND CRYSTAL STRUCTURE OF DEGRADATION PRODUCT ARTEMISININE-ENDOCYCLIC KETONE SESQUITERPENE LACTONE
Lin Xiu-yun, Zhang Shu-de, Wu Shen
1983, 32 (4): 553-558. doi: 10.7498/aps.32.553
Abstract +
This compound is a QINGHAOSU degradation product. The molecule consists of 14 carbon, 20 hydrogen, and 3 oxygen atoms. It crystallizes in the orthorhombic system with space group P21 21 21. There are four molecules in a unit cell, the lattice parameters are a = 16.997?, b = 10.298?, and c = 7.394?.The three-dimensional intensity data were collected by using PW-1100 four-circle diff-ractometer and the number of the independent diffractions amounts to 1377. The crystal structure was solved by direct methods. The positions of 14 atoms were given by E map and the additional carbon atom sites were obtained by cycle of Fourier synthses. The structure was refined by block-diagonal least square method. The final R-factor is 0.084.