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Vol. 35, No. 7 (1986)

1986-04-05
CONTENT
A STUDY ON SUBSTUTION OF Fe IN BaFe12O19 BY Mn
FU HUA, ZHAI HONG-RU, ZHANG YU-CHANG, GU BEN-XI, LI JlNG-YUAN
1986, 35 (7): 833-840. doi: 10.7498/aps.35.833
Abstract +
In this paper, we studied the substitution of Fe in BaFe12O19 by Mn. The main results are as follows: (1) For polycrystalline materials of composition BaFe12-xMnxO19, the amount of maximum substitution of Mn is x=4, and the valence of Mn ions are mostly 3+. (2) Mn ions enter only 12 k and 2 a sites, and noncolinear spin structure appears with higher content of Mn (3) The saturation magnetization σ, the anisotropy constant k1 and the Curie temperatur Tc decreas with the increase of Mn content. (4) The zero field splitting constant Dh of Mn in M-type hexagonal structure is lower then that in garnet structure.
MAGNETIC PROPERTIES, ELECTRICAL RESISTIVITY AND CRYSTALLIZATION BEHAVIOR OF AMORPHOUS Fe90-xBxZr10 ALLOYS
CHEN JIN-CHANG, SHEN BAO-GEN, ZHAN WEN-SHAN, ZHAO JIAN-GAO
1986, 35 (7): 841-849. doi: 10.7498/aps.35.841
Abstract +
The effects of B content on the magnetic and electrical properties and crystallization behavior of amorphous alloys based on FeZr are studied in this paper, and compared with amorphous FeB alloys. The reasons of the average magnetic moment per FeZr atoms. μFeZr and Curie temperatures Tc increase with increasing B content are explained. Finally, the scattering mechanisms of electrical resistivity at various temperatures and effects of B or Zr element on the crystallization temperature in these alloys are discussed.
STUDIES ON PRODUCING AMORPHOUS ALLOY LAYERS BY BORON ION IMPLANTATION INTO POLYCRYSTALLINE IRON FILMS
ZHANG YUE-LU, MEI LIANG-MO, GUO YI-CHENG, GUO XIAO-QIN, CONG PEI-JIE
1986, 35 (7): 850-854. doi: 10.7498/aps.35.850
Abstract +
Production of amorphous alloy layer in pure polycrystalline iron thin film by boron ion implantatiom has been studied and interesting phenomena have been observed such as the magnetic coercive field of the film decreases non-monotonously with increasing ion dose, etc. The possible mechanisms of the phenomena have been discussed.
THE PERTURBATION SOLUTION OF OPTICAL BLOCH EQUATION WITH RELAXATION TERMS IN SATURATED SPECTROSCOPY
WANG QING-JI, XIE CHUAN
1986, 35 (7): 855-863. doi: 10.7498/aps.35.855
Abstract +
Tn this paper, the optical Bloeh equation with relaxation terms in saturated spe-ctroseopy is solved directly by using the perturbation theory. The reenrren formulas are given, approximate results of any order can be obtained from them. The first and second order solutions are derived and explained.
PULSE CALIBRATION TECHNIQUE OF X-RAY DETECTOR
SUN JING-WEN
1986, 35 (7): 864-873. doi: 10.7498/aps.35.864
Abstract +
A pulsed CuK X-ray source with flux intensity 1018-1019 K X-rays per sr per s has been produced using high current electron beam technique, it has been employed to calibrate the response of the silicon PIN diode detector to pulsed X-ray photon. An absolute X-ray monitor——P10 gas pulse ionization chamber has been used as a standard of the pulsed X-ray flux density, the automatic pulsed charge measuring instrument is controlled and Corrected in real time by a microcomputer. The measured uncertainty of the flux density is ±5%. This chamber is suitable for the range of energy flux rate 4×10-9-2×102 W/cm2 and the range of photon energy 1.5-10 keV. The calibrated accuracy of the detector is ±7.0%. It is found that the pulsed sensitivity of the silicon PIN diode is about 30% higher than the sensitivity calibrated by a steady X-ray beams.
STABLE REGION OF TOKAMAK DEVICE FEEDBACK CONTROL (Ⅰ)——THEORETICAL
ZHENG SHAO-BAI, SHEN ZHONG-QING
1986, 35 (7): 874-881. doi: 10.7498/aps.35.874
Abstract +
In this paper, the evolution equations of feedback control of plasma current and horizontal displacement simultineously in a tokamak device are presented. Under the assumption of small disturbance and linear approximation, the stability criterion and the stable region of CT-6B tokamak feedback control is given.
STEADY-STATE ELECTRIC FIELD STRUCTURE AND DENSITY PROFILE IN A PLASMA IRRADIATED BY DOUBLE-FREQUENCY LASER
SHEN WEN-DA, ZHU SHI-TONG
1986, 35 (7): 882-888. doi: 10.7498/aps.35.882
Abstract +
The analytic expressions for steady-state electric field intensity and local scale length in a plasma irradiated by doublefrequency laser are derived. It is shown that the ponderomotive force due to double-frequency laser field would lead to the local density dip near critical surface and the anamolous increase and fluctuation of the critical scale length in some region of field intensity value.
THE THERMAL BEHAVIOR OF ELASTIC CONSTANTS OF BERLINITE (α-AlPO4)
WANG HONG, XU BIN, HAN JIAN-RU, LI TI-JIU, HUO LUO-YUN
1986, 35 (7): 889-895. doi: 10.7498/aps.35.889
Abstract +
Samples of berlinite (α-AlPO4) have been grown by slow heating method. The thermal behavior of elastic prepeties have been studied by transmission method from 30℃ to 150℃. The equations for the temperature behevior of elastic constants have been obtained by polynomial least square method and the 1st, 2nd and 3rd order temperature coefficients of the elastic constants have been calculated (T0=25℃).
THE INFRARED DIVERGENCE RESPONSE OF STRUCTURAL RELAXATION IN GLASSES
FAN XI-QING, WANG GUO-LIANG, LIU FU-SUI
1986, 35 (7): 896-904. doi: 10.7498/aps.35.896
Abstract +
The infrared divergence response theory is applied to the two-level System model of structural defects in glasses, and the twopeak structure of the ultrasonic absorption is explained by this theory. It is reasoned out that the small low-temperature peak depends more strongly on frequency than that of the high-temperature peak. On the basis of indroducing the effective potential, a good agreement with experimental data for ultrasonic aibsorption in SiO2 is attained over the whole temperature range.
MULTIPHONON ABSORPTION IN InP
ZHANG YU-AI, JIANG DE-SHENG, XU ZHEN-JIA
1986, 35 (7): 905-913. doi: 10.7498/aps.35.905
Abstract +
IR absorption measurements have been made using a high resolution Fourier-transform spectrometer on crystals of InP in the 400-4000 cm-1 region at temperature between 11-300 K. Very weak new absorption bands are observed, their absorption coefficients are ~10-1 cm-1, were observed at 996cm-1, 965cm-1, 932cm-1, 838cm-1, 776 cm-1, 742cm-1, 718cm-1,590cm-1, 558cm-1 and 538 cm-1. The frequencies and temperature dependence of these weak bands indicate that they arise from three-phonon processes and appropriate assignments are given. Using IR absorption technique, we observed for the first time the boron contamination in LEC(B2O3)-CZ InP crystals. The content of baron contamination has been proved to be ~10-16cm-1.
A NEW METHOD TO DETERMINE BACKSCATTERING FACTORS FOR QUANTITATIVE AUGER ANALYSIS
WANG QIAN, ZHANG QIANG-JI, HUA ZHONG-YI
1986, 35 (7): 914-921. doi: 10.7498/aps.35.914
Abstract +
A new method is proposed for determining the backscattering factor using information provided by the background off an direct Auger spectrum N(E). Complicated calculations such as the Monte Carlo method were avoided, and the quantitative Auger analysis accuracy could be further improved since the calculations of backscattering factor was based on the spectra. The examples of determining the compositions of Au-Cu and Ag-Cu alloys are given. These results are compared with that obtained by other mothods.
THEORETICAL INTERPRETATION OF RESONANCE RAMAN SCATTERING IN cis-POLYACETYLENE
YU LU, GUO YOU-JIANG
1986, 35 (7): 922-930. doi: 10.7498/aps.35.922
Abstract +
A bipolaron microscopic model is proposed in this paper to interpret theoretically the Raman scattering data in cis-polyacetylene on the basis of lattice relaxation theory. The coupling of electron to different phonon modes is taken into account, the coupling constants being determined from the infrared and the Raman data. The theoretical results thus obtained are compared with the experimental data and discussed. The method used in this paper can be generalized to other similar systems.
EXACT CONTINUUM MODEL FOR POLYACETYLENE
WU ZI-YU, WANG KE-LIN
1986, 35 (7): 931-938. doi: 10.7498/aps.35.931
Abstract +
On the basis of the continuum version of the SSH Hamiltonian, we obtain a set of equations for the electronic wave function, which reduces to the BdG equations in the TLM model with neglect of certain terms. The new set of equations has been solved rigorously and analytically with the solution reducing to SSH's simple kink function in the zeroth approximation.
BRIEF REPORT
THE LOCAL DENSITY OF STATES FOR THE NARROW CHANNELS OF THE SEMICONDUCTOR SURFACE
YE HONG-JUAN
1986, 35 (7): 939-943. doi: 10.7498/aps.35.939
Abstract +
In the sub-micron channels of semiconductor surface, it has been found that the conductivity has oscillation structure with gate voltage. We calculate the local density of states for the narrow channel by using Green function method and see that the density of states shows a series of sharp peaks, which can be used to explain qualitatively the conductivity oscillation.
A NEW SENSITIVE METHOD FOR DETECTING R. F. RESONANCE IN OPTICAL PUMPING EXPERIMENT
LIU SHU-QIN, DONG TAI-QIAN
1986, 35 (7): 944-946. doi: 10.7498/aps.35.944
Abstract +
By making use the influence of microwave-r.f. multi-quantum transition on the spectral line intensity of single quantum microwave transition, a new sensitive method for detecting r.f. resonance in optical pumping experiment is found.
COMPARISION OF TWO COLLISION MODELS IN PLASMA
ZHANG CHENG-FU
1986, 35 (7): 947-952. doi: 10.7498/aps.35.947
Abstract +
In this paper, the effects of collision on the dispersion equation of plasma are discussed under two kinds of collision models (BGK model and LB model). Analysis shows that the main effect of collision is to change the usual dispersion function Z(ξ) into a generalized one W(ξ,ν). The properties of W function have been analysed and compared for two models. The effects of collision on low frequeny drift wave (local mode) and ion-acoustic wave have been discussed. It is shown that LB model is not only more reasonable physically than BGK model, but also more simple in calculation and expression.
THE HARMONIC EFFECT ON EXAFS AMPLITUDE IN POLY-ELEMENT SYSTEMS
WAN JUN, LU KUN-QUAN, ZHAO YA-QIN, CHANG LONG-CUN, FANG ZHENG-ZHI
1986, 35 (7): 953-955. doi: 10.7498/aps.35.953
Abstract +
A method to calculate the harmonic effect on EXAFS amplitude for poly-element systems is given. Results calculated and measured are presented. They are consistent with each other.
MEASUREMENT OF THE (5p1/2nd)3 AUTO-IONIZING LEVELS OF STRONTIUM
WU BI-RU, ZHANG SEN, LU JIE, HU SU-FEN, QIU JI-ZHEN, SUN JIA-ZHEN
1986, 35 (7): 956-960. doi: 10.7498/aps.35.956
Abstract +
The (5p1/2nd)3 (n=ll—24) auto-ionizing levels of Sr have been measured by the laser melti-step excitation technique. Their effective quantum numbers have been determined. The interaction with the (5p3/2nd)3 series has been discussed.
THE INFLUENCE OF INTERFACIAL DIFFUSION ON THE ELECTRONIC STRUCTURES OF THE SUPERLATTICES
PANG GEN-DI, XIONG SHI-JIE, CAI JIAN-HUA
1986, 35 (7): 961-964. doi: 10.7498/aps.35.961
Abstract +
We have calculated the influence of the interfacial diffusion on the electronic structures of the metallic superlattices by using the CPA method. It is found that the local electronic densities of states, either corresponding to the regions of interdiffusion or to the regions without interdiff asion, are affected by this process of atomic diffusions.
A TEM STUDY OF Pd-Si THIN FILM SOLID-PHASE REACTION
ZHANG JING, LIU AN-SHENG, WU ZI-QIN, GUO KE-XIN
1986, 35 (7): 965-968. doi: 10.7498/aps.35.965
Abstract +
The initial silicide formation during the deposition of Pd to room-temperature Si (111) substrate and the dependence of Pd2Si-Si orientation relationship on Pd film thickness have been studied by TEM. The results show that the only silicide phase formed is Pd2Si under annealing temperature from 170℃ to 600℃. A thin layer of Pd2Si has grown without annealing, even when the substrate is kept in room-temperature. The Pd film thinner than 100 nm leads to epitaxial Pd2Si layer on Si (111), while the Pd film of about 400 nm gives the [0001] Pd2Si fiber texture. Various kinds of defect with high density exist in the silicide film and the interface.