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Vol. 30, No. 2 (1981)

1981-01-20
CONTENT
GENERAL THEORY OF OPEN RESONATOR WITH ROTATIONAL SYMMETRIC WAVEGUIDES
ZHOU LE-ZHU, XU CHENG-HE, GONG ZHONG-LIN
1981, 30 (2): 153-163. doi: 10.7498/aps.30.153
Abstract +
A general theory is developed on the open resonator with rotational symmetric wave-guides which have been used extensively in the electron cyclotron maser (gyrotron). The theoretical analysis is carried unt under the most general conditions, that is the cross-sec-tion radius r(z) is a slowly varying arbitrary function and the resonaor is open. Prperties of the field solutions in the resonator have been discussed, general expressions for the resonant frequencies and Q values have been derived. Calculation results for a concrete resonator are presented.
TIME REVERSAL SYMMETRY AND NON-EQUILIBRIUM STATISTICAL STATIONARY STATES (I)
ZHOU GUANG-ZHAO, SU ZHAO-BIN
1981, 30 (2): 164-171. doi: 10.7498/aps.30.164
Abstract +
This is the first part of our work on time reversal symmetry applied to non-equi-librium statistical stationary states from a unified microscopic quantum statistical point of view. In this paper, a formalism for time reversal symmetry is constructed in the framework of the Closed Time Path Green's Functions (CTPGF), which can be applied both to equilibrium and non-equilibrium stationary states. By using the generating functional technique of the CTPGF, symmetry relations for the statistical Green's functions and vertex runctions are derived for systems invariant under time reversal.
THE CHARGE TRANSFER AND SPLITTING OF 4d ORBITALS OF Mo ATOM IN CHEVREL PHASE MxMo6S8 COMPOUNDS
WU GUO-ZHEN
1981, 30 (2): 172-177. doi: 10.7498/aps.30.172
Abstract +
In this paper, the ligand field method is applied to derive an analytic expression relating the charge transfer between M and Mo6S8 cluster and the splitting of the 4d orbitals of Mo atom for Chevrel phase MzMo6S8 compounds. From the reflection spectrum of PbMo6S8 the charge transfer from Mo6S8 cluster to Pb atom is calculated to be 1.18 instead of 2 electrons being transferred from Pb atom to Mo6S8 cluster as generally recognized in previous literatures. The number of 4d electrons on Mo6 is therefore 18.8.
IMPROVEMENTS ON THE FLUCTUATION MODEL OF PASSIVELY MODE-LOCKED LASERS
ZHU ZHEN-HE, HUO CHONG-RU
1981, 30 (2): 178-188. doi: 10.7498/aps.30.178
Abstract +
The fluctuation model of passively mode-locked lasers has been improved. A com-puter simulation of the evolution of light pulses was performed. The simulation started at the point when the gain coefficient had just increased to the threshold value. The starting average intensity was calculated in accordance with the spontaneous emission The rate of pumping, the life-time of the upper laser level and the ratio of the area of beam section at the gain medium to that at the saturable absorber were taken into ac-count. The calculation has been done for Nd-glass and Nd: YAG lasers.The simulation calculation led to the following conclusions: (1) It is impossible to obtain complete mode locking with a confidence over 93% when the pumping rate exceeds the threshold value by 15 to 20%. (2) The optimum ratio of the area of the beam sections is from 1/2 to 1 for Nd-glass lasers, and larger than 2 for Nd: YAG lasers. (3) To obtain complete mode locking the transmission of the saturable dye must be within a certain range (depending on the loss coefficient and the ratio of the beam sections). The transmission of the dye for Nd-glass lasers should be higher than that for Nd: YAG lasers, if the same dye is employed.Finally, the shortcomings of Glenn's calculation are pointed out.
INVESTIGATION OF DEGENERATE FOUR-WAVE MIXING AND PHASE CONJUGATION IN ORGANIC DYE SOLUTIONS
WU CUN-KAI, FAN JUN-YIN, WANG ZHI-YING
1981, 30 (2): 189-198. doi: 10.7498/aps.30.189
Abstract +
Phase conjugation of backward-and forward-wave produced by degenerate four-wave mixing using a nearly resonantly enhanced nonlinearity in four-level organic dye solutions was investigated. The conversion efficiency of 22% had been obtained in a 2.5 X 10-5 - molar solution of Chlorophyll A in methylalcohol with a 5 mm interaction length and a pumping energy of ~ 8 mJ from SH of a Q-switched Nd: YAG. Degene-rate four-wave mixing by two-photon resonant-enhancement in the solution of rhodamine 6G in alcohol was studied. Measurements were performed which described the dependence of nonlinear reflectivities on the molar concentrations of the media and the intensities of the pumping and object waves. Phase conjugation characteristics of forward-wave in four-wave mixing process were theoretically analysed. Experiments have cofirmed the theoretical prediction. The method of quartet degenerate four-wave mixing had been ex-tended to the doublet degenerate case. Using this method image conversion from 1.06 μm to 5320 ? had been realized with a conversion efficiency of 25% in a 5 mm long satu-rable absorber made of organic dye 9740 solution in dichloroethane. Theoretical analy-sis showed that using a medium, which is a near resonant absorber for the infrared object wave but is transparent for the visible reconstruction wave, the conversion efficiency may be well in excess of unity.
RAMAN MIXING IN AN OPTICAL FIBER
YANG TIAN-LONG, SU HAI-ZHENG, GAO PEI-JUAN
1981, 30 (2): 199-207. doi: 10.7498/aps.30.199
Abstract +
The tuning Raman mixing effects in an optical fiber have been investigated in the frequency shift range from 656cm-1 to 1343cm-1. Many phenomena have been obser-ved experimentally, e.g., the intensity of coherent anti-Stokes Eaman scattering (CAES) is inversely proportional to that of the inverse Raman absorption (VRA), the energy distribution of SRS is influenced strongly by Raman mixing (RM). In addition to the-coherent Stokes Raman scattering (CSRS) and CARS radiations, the second order coherent Stokes Raman scattering (SOCSRS) and the second order anti-Stokes Raman scattering (SOCARS) radiations have also been observed. Finally, the experimental results are discussed.
NO-STANDARDS QUANTITATIVE EDS ANALYSIS OF THE CONSTITUENTS OF BINARY ALLOYS CONTAINING LIGHT ELEMENTS
ZHANG REN-JI, GE SEN-LIN, WU ZI-QIN
1981, 30 (2): 208-217. doi: 10.7498/aps.30.208
Abstract +
In this article, the no-standards quantitative analysis method using the ratios of the X-ray intensities of the elements in the samples has been improved. The "full diffusion" model of the electron scattering has been properly modified and simplified and a stepped depth distribution curve of the X ray has been obtained. From this distribution curve, the quantitative relationship between the constituents of samples and the intensities of the characteristic X-rays has been determined. The analysed values of the Cu-Si, FeS2 NaCl and GaAs are coincident with the actual values. Our results are better in some extent than the results of Russ's method which used the calculated X-ray intensity factors of pure elements and the routine ZAF correction. The calculation procedure of our method is also simpler than the procedure of the latter method.
THE NEEDLE-LIKE STRESS ZONES AND DISLOCATIONS DUE TO CONSTITUTIONAL SUPERCOOLING IN CZOCHRALSKI METHOD-GROWN YAG SINGLE CRYSTALS
GE CHUAN-ZHEN, XU XIU-YING, FENG DUAN
1981, 30 (2): 218-223. doi: 10.7498/aps.30.218
Abstract +
In this paper, we studied the relationship between the morphological development of the solid-liquid interface and the needle-like stress zones in Czochralskimethod-grown YAG single crystals doped with Nd. The experimental results established that the needle-like stress zones were originated from the solute (Nd) -rich zones due to constitutional supercooling. By studying the needle-like stress zones with photo-elasticity method, the stress in these zones was found to be axially symmetrical comperssive. We have also studied dislocation arrays along the boundaries of solute (Nd)-rich zones by means of etching method and birefringence observation, and measured the dis location density. The measured density agrees roughly with the value estimated according to the theory of misfit dislocations.
COMPUTER ANALYSIS OF PATTERSON MAP
HAN FU-SEN, FAN HAI-FU
1981, 30 (2): 224-233. doi: 10.7498/aps.30.224
Abstract +
In this paper, a procedure for automatically analysing of Patterson map is given. Details of the computer program designning and examples in practical use are also discribed.
INVESTIGATION OF THE PSEUDO-BINARY SYSTEM LilO3-Zn(IO3)2
TANG DI-SHENG, FU ZHENG-MING, LI WEN-XIU
1981, 30 (2): 234-241. doi: 10.7498/aps.30.234
Abstract +
The pseudo-binary system LiIO3-Zn(IO3)2 has been investigated and its phase diag-ram determined by means of X-ray diffraction and DTA, using specimens prepared by solid state powder sintering method. A new phase, the formula of which can be written as LiZn(IO3)3, has been found to exist in single phase within a wide range of composi-tions. It is an ionic conductor and has remarkable SHG effect as determined by the powder method. The lattice paremeters of the compound LiZn(IO3)3 have been determined by a computer programme, using the powder diffraction data. It is found that the compound belongs to orthorhombic system with a = 8.081?, b = 8.729?, c = 11.595?, z = 4.
DETERMINATION OF ISOSARMENTOSIN CRYSTAL STRUCTURE (I)
ZHENG QI-TAI, ZHENG CHAO-DE, QIAN JIN-ZI, GU YUAN-XIN
1981, 30 (2): 242-248. doi: 10.7498/aps.30.242
Abstract +
The Isosarmentosim crystal C11H17O7N belongs to monoclinic system. The space group is C22 -P21. The crystal parametera are a = 12.185 (±0.005)?, b = 10.318 (±0.005)?,c = 4.853 (±0.004)?, β = 98.80 (±0.08) °. Two molecules are contained in a unit cell, c = 2. The diffraction data has been collected bylusing PW-1100 four-circle diffra-ctomter, the total number of independent diffractions amounts to 1139. The crystal structure has been determined by direct method (MULTAN-78), and structure parameter has been refined by means of block matrix least-squares method, R= 0.058. The difference Fourier syntheses gives out all the hydrogen position. Between the molecules there exist hydrogen-bonds, the avarage length of which are 2.869?.
MICROSCOPIC OBSERVATION OF DIFFUSION DISTRIBUTION OF IONIZED IMPURITIES IN SILICON
ZENG QING-CHENG
1981, 30 (2): 249-253. doi: 10.7498/aps.30.249
Abstract +
We present in this paper a microscopic method for revealing the diffusion distribu-tion of ionized impurities in silicon during the oxidizing electrolysis process of water. This method is effective and comparatively simple. The colored micrographs obtained are also included here.
STUDY OF THE MAGNETIC PROPERTIES AND M?SSBAUER EFFECT OF A Fe-Cr-Co-Si PERMANENT MAGNETIC ALLOY
LI DONG-SHENG, SHAO HAN-RU, LI SHI, WU WEI-FANG, LI GUO-DONG, FENG MIN-YING
1981, 30 (2): 254-259. doi: 10.7498/aps.30.254
Abstract +
A workable permanent magnetic alloy was studied. Its composition was 65Fe-22Cr-12Co-l Si (in wt%). The temperature dependence of the magnetic saturation moment and the M?ssbauer spectra under room temperature and at about 80K were investigated for the quenched samples as well as those which was the heattreated in magnetic field and aged, the parameters of a spectrum were calculated. It was showed from experiments that the magnetic properties of these two kind of samples were changed in the heating and cooling cycles in measurements. For the aged sample, a paramagnetic phase appeared under room temperature in addition to the ferromagnetic phases, this paramagnetic phase transformed into ferromagnetic phase at low temperatures. An incomplete orientation effect of the magnetic moment was discovered. Finally, the reverse magnetization mechanism and the tentative way of improving coercive force were discussed.
PHASE IN Fe-C, Fe-C-Sb ALLOY SYSTEMS OBTAINED BY SPLAT QUENCHING
WU DE-HAI, LIN ZHI-WEI, LI CHUN-LI, LIANG GUANG-QI, LU JIN-WEN, CHEN XI-CHEN, YI SUN-SHENG, WANG ZU-LUN
1981, 30 (2): 260-265. doi: 10.7498/aps.30.260
Abstract +
An ε metastable phase of h.c.p. structure has been obtained in the alloy systems Fe-C, Fe-C-Sb by means of splat quenching. The ε phase is a solid solution the lattices constant of which increases with increase of Sb and C, but the value c/a is approximately constant. The ε phase of the Fe-C-Sb alloy is fairly stable thermally. DTA shows that the ε phase is non-dissociative below 125℃ and the addition of Si and Sb increases the stability. The grain size of the e phase is of the order of 10-1 micron. Our work verifies that of R.C. Ruhl and M. Cohen et al. concerning the e phase of the Fe-C-Si alloy. The topography of this ε phase has been studied by means of scanning and transmission electron microscopy.
BRIEF REPORT
ON ELECTROMAGNETIC INSTABILITIES OF PLASMA (II)
LU QUAN-KANG
1981, 30 (2): 266-270. doi: 10.7498/aps.30.266
Abstract +
In paper [1], a strict and general instability criterion is obtained by analysing the geometric properties of the dispersion relation of electromagnetic waves in plasma with anisotropic velocity distribution, but the wave propagates only along one specific direction. In this paper, the propagation of electromagnetic waves along an arbitrary direction is discussed. The rigorous instability criterion is obtained.
HIGH TEMPERATURE SUPERCONDUCTIVITY IN METALLIC HYDROGEN
ZHU ZAI-WAN, JIANG WEN-ZHI
1981, 30 (2): 271-276. doi: 10.7498/aps.30.271
Abstract +
The present paper gives an expression of the effective phonon spectrum a2F(ω),spectrum area λ/2 and electron-phonon coupling constant A of the metal with valence Z in terms of a few parameters, such as average electronic radius rs, Ion mass M and sound velocity vj. Using the formula of Dynes, we have calculated the superconducting transition temperature Tc for matalic hydrogen, lead and niobium. It is shown that matalic hydrogen has λ = 2.55 and Tc = 162 K at zero pressure.
THE Tc-λ CURVE
ZHOU ZI-FANG, GU YI-MING, MAO DE-QIANG, WU HANG-SHENG
1981, 30 (2): 277-280. doi: 10.7498/aps.30.277
Abstract +
The present letter shows that the Tc-λ curve is composed of three parts with entirely different properties, namely, "McMillan region", "λ1.55 region" and "series solution region".
ON THE STABILITY OF A WANNIER EXCITON IN A POLAR CRYSTAL
GU SHI-WEI, LIANG XI-XIA
1981, 30 (2): 281-285. doi: 10.7498/aps.30.281
Abstract +
In this paper, the ground state energy of a wannier exciton is calculated by means of the effective Hamiltonian obtained by one of the authors. It is shown that there is a range of values of the electron-tohole mass ratio a, for which the exciton. is stable with respect to dissociation into a free electron and a free hole.
THE PREPARATION OF TRANSMISSION ELECTRON MICROSCOPE SPECIMEN BY ELECTROLYTIC POLISHING METHOD
CHENG PENG-ZHU, MA XIAO-HUA, LUO QI-GUANG, YANG DA-YU
1981, 30 (2): 286-290. doi: 10.7498/aps.30.286
Abstract +
The transmitting and reflecting optical microscopy has been used in the electrolytic polishing process for monitoring the polished specimen to obtain the optimum polishing condition. The intermittent current device has been employed in the electric circuit so that the control of the polishing condition becomes more feasible. The efficiency and reproducibility of specieen preparation have been improved. The transmission electron microscopy specimen of some superconducting and amorphous materials have been pre-pared by this technique and the electron microscopy and selected area electron diffrac-tion observations have been made.
INJECTION LOCKING OF DYE LASERS
PAN SHAO-HUA, TANG XIAO, FENG BAO-HUA
1981, 30 (2): 291-296. doi: 10.7498/aps.30.291
Abstract +
The phenomena of injection locking of dye lasers have been observed experimentally. Expressions for the competition between injected and non-injected modes are deduced according to the semiclassical theory of lasers. The results are in relatively good agreement with experiments.