Vol. 30, No. 1 (1981)
1981, 30 (1): 1-11. doi: 10.7498/aps.30.1
Device of pulse optical pumping and pulse sampling optical detection is presentedto reduce the light shift in Rb87 atomic frequency standard. The 0-0 transitionlineshape and light shift is calculated. It is qualitatively, inagreement with the experimen-tal results. With this device, one may expect to improve the long term frequency sta-bility of the passive Rb87 atomic frequeney standard.
ON THE CHARACTERISTIC IMPEDANCE OF A COAXIAL LINE WITH ELLIPTIC OUTER CONDUCTOR AND RECTANGULAR INNER CONDUCTOR
1981, 30 (1): 12-21. doi: 10.7498/aps.30.12
In this paper, the methods using the graphical approximation and taking the geo-metrical average of the upper and lower bounds to the size of the line are put forward, to calculate the characteristic impedance of a coaxial line with elliptic outer conductor and rectangular inner conductor. The boundary of rectangular inner conductor is con-formally mapped into a closed curve which is nearly a rectangle, and its inscribed con-focal ellipse and outer connected confocal ellipse are conformally mapped into two con-centric circles, the geometrical average of the both is taken as its equivalent value. At the same time, the boundary of elliptic outer conductor is conformally mapped into a concentric circle. So they constitute a standard coaxial line, and the formula for calculating its characteristic impedance is obtained.The calculating formulae of the characteristic impedance of some eoaxial lines (i. e. elliptic outer and microstrip inner conductors, circular outer and square inner conduc-tors, circular outer and rectangular inner conductors) in elementary functional forms are derived, so that the lengthy and complicated integral calculation involving elliptical functions are avoided. The characteristic impedances of some coaxical lines as mention-ed above are given in accurate values for references.
THE CONFORMASTAT FLAT SOLUTION AND THE NORMALITY OF THE ENERGY-MONENTUM PSEUDO-TENSOR OF GRAVITATIONAL FIELD IN THE THEORY OF GRAVITATION
1981, 30 (1): 22-27. doi: 10.7498/aps.30.22
In this paper, we have found the conformastat flat solution in the theory of gravita-tion by eondering the vector graviton field and the metric field. We introduce Hu-Ning's expression into this theory, then it appears also as the conservative expression of energy-monentum. For the gravitational field of singular centralized mass, it can be shown, as in GR, that the gravitational mass and the inertial mass are equal. But Einstein's principle of equivalence doesn't hold in this theory. When n
1981, 30 (1): 28-34. doi: 10.7498/aps.30.28
In super space (x, θ), as the metric tensor field GAB(x, θ) is given, we calculated the Riemann curvature tensor RDABC of fourth rank and its generalized cyclicity.The equation that must be satisfied by isometry in the super space, i.e. super Killing equation: ξA:B+ηabξB:A=0, is deduced.In flat super space with zero curvature tensor, we have obtained the general solu-tions of the super Killing equation and the commutation relations of the corresponding generators. In the case of constant curvature, we have obtained a special solution of the super Killing equation.
In this work, analysis of the space-time manifold, their kinematic groups and Lie algebras are made intuitive as far as possible. First of all, from the analysis of the iner-tial frames it is shown that according to the Beltrami theorem in Riemann Geometry, the space-time manifold, in which there exists global inertial frame, should be a pseudo-sphere. So that the kinematic group must be a rotation group, thus the explicity analy-tical expressions of such kinematical transformations and the commutative relations among the corresponding generators can be formulated easily. Consequently, the con-tractions of such manifolds, kinematic groups and Lie algebras can be deduced concretely and intuitively.
1981, 30 (1): 46-56. doi: 10.7498/aps.30.46
In this paper, we discuss the problem of the local energy content in gravitational fields. A new total energy-momentum density pseudo-tensor of gravitational field is given In this paper. The energy content in any part of a gravitational field given by the new pseudo-tensor is an invariant under arbitrary purely spatial transformation, hence the local energy content in the gravitational field has a well-defined physical meaning. For the energy and momentum of a Schwarzschild gravitational field, the results given by the new pseudo-tensor are more reasonable than those given by other pseudo-tensors pro-posed in the literatures of the general theory of relativity.The relation between mass and energy in the theory of gravitation is also discussed.
1981, 30 (1): 57-65. doi: 10.7498/aps.30.57
A technique of spatial encoding color photographic image in a black and white tran-sparency for coherent polychromatic processing is presented. The applications of this technique to color image signal detection, restoration of color blurred images, and color image addition and subtraction are provided. We note that this polychromatic processing technique is capable of processing color images similar to monochromatic coherent pro-cessing technique. Although there is a disadvantage of this technique, it requires an en-coding step for image processing, however this technique may open a new dimension in color image processing. We also note that the application of this technique is not res-tricted only to color images, it may apply to some problems in gray level transparencies.
General methods of calculating indefinite integrals of the type ∫xnA(p)B(q)dx are pre-sented, where A and B are solutions of the Airy equition y" = (λ + x)y with the para-meterλ, p, q are the order of differential, n is a non-negative integer. General formulae of this type of integrals is given for corresponding p, q ≤1 and functions A, B with dif-ferent parameters. For A=B a method of integration is also obtained, which is quite dif-ferent from that of Albright. As an application, these formulae of integrals are applied to the problem of the orthonormalization of the wave functions of an electron in a triangular potential well, and the transition probabilities between the energy-levels are obtained.
1981, 30 (1): 84-90. doi: 10.7498/aps.30.84
Various important factors determining the snap-off time of the step-recovery-diode (SRD) are investigated. In addition, a new structure of SED is proposed, that is n+pp+ diode with abrupt n+p junction and narrow p base region. The analysis shows that because the carriers injected into the base region have larger diffusion coefficient, the snap-off time of such diode is greatly reduced. The process used to produce this diode is also described, and many diodes produced by this method have been employed in many practical circuits. The best result of the snap-off time is smaller than 50 ps (10-90%).
A SCHEME TO CONTROL THE FIRST-SECOND CYCLE AMPLITUDE RATIO OF TRANSDUCERS FOR ULTRASONIC MEASUREMENTS
1981, 30 (1): 91-96. doi: 10.7498/aps.30.91
In the ultrasonic applications of measuring non-acoustic characteristics, it is impor-tant that the time of flight of the ultrasound be measured with accuracy. One significant step to achieve this is to ensure that the first few cycles of the received ultrasonic signal should not be missed. This in turns asks for the amplitude of the first cycle being as large as, or greater than, that of the second. By studying the transient responses of the transmitting and receiving transducers, either separated or two united in one, it is shown that the first second cycle amplitude ratio can be increased from less than one to one or more of the specific acoustic resistance of the transducer backing is enhanced to a suf-ficiently high value, but not necessarily as high as the specific acoustic resistance of the piezoelectric plate. This holds for the case of light loading. For the case of heavy load-ing, the amplitude ratio is found to be inherently large.
1981, 30 (1): 97-104. doi: 10.7498/aps.30.97
The method of cumulants expansion for both averaged singleparticle and two-par-ticle Green's functions for a disordered binary alloy is extended to treat a disordered n-component alloy. Within the single-site approximation, if the multipleoccupancy cor-rections are treated self-consistently, it is shown that both averaged single-particle and two-particle Green's function agree with the results of coherent potential approximation.
1981, 30 (1): 105-110. doi: 10.7498/aps.30.105
We present here a preliminary theoretical study on the lineshift of the Kα radiation from atomic ions. The systematic variation of the Kα radiation shift on the degree of ionization as well as the atomic number is examined up to the intermediate-Z element Mo. We also argued that measurements on such Kα spectra are relevant to impurity diagnostics in plasmas.
1981, 30 (1): 111-116. doi: 10.7498/aps.30.111
A modified tangent formular taking account of the presence of heavy atoms is given in this paper. It is of the form:The modified tangent formular has the advantage of being able to eliminate the squaring effect. Practical examination shows that it is superior to the conventional tangent formular and can resolve the ambiguity due to the coexistence of both enan-tiomorphs.
1981, 30 (1): 117-119. doi: 10.7498/aps.30.117
The internal friction peaks in Al-0.5wt%Cu alloys were observed near 0℃ and 90℃ respectively under forced bending vibration within the audio frequency range and the amplitude internal friction peaks were observed at 6℃ and 90℃. It may be considered as an anomalous internal friction phenomenon showing both temperature peaks and am-plitude peaks. It is suggested that the peaks may be associated with the motion of disloca-tions dragged by point defects.
1981, 30 (1): 120-123. doi: 10.7498/aps.30.120
The γ-Fe2O3 powder with CoxFe3-xO4-doped coating was obtained by reaction of the γ-Fe2O3 powder in the solutions containing Co++ and Fe++ ions. It was found that this epitaxial CoxFe3-xO4 coating raised the coercivity of the γ-Fe2O3 from 420 (Oe) to 715 (Oe).The epitaxial CoxFe3-xO4 coating was isvestigated by means of M?ssbauer Effect of 57Fe. The M?ssbauer Spectrum indicates that the surface of γ-Fe2O3 was doped with CoxFe3-xO4 solid solution, and a static magnetic interaction takes place between the γ-Fe2O3 matrix and CoxFe3-xO4 solid solution.
A METHOD OF SOLVING SIMULTANEOUS EPUATIONS FOR OBTAINING LATTICE CONSTANTS OF LOW-SYMMETRY CRYSTAL SYSTEMS
1981, 30 (1): 124-131. doi: 10.7498/aps.30.124
We present here a method of solving the simultaneous equations for obtaining lattice constants of low-symmetry crystal systems (triclinic, monoclinic and orthorhombic systems) by using all available diffraction data. Due to the measuring error, about 10 per cent of the data would show larger diviation. But most of the data are rather accurate and still distribute close to the true value statistically. Therefore, using a certain pro-grammed method for reasonable selection of data the best result of average values of lat-tice constant can be obtained.
1981, 30 (1): 130-132. doi: 10.7498/aps.30.130
For certain types of crystal structure containing heavy atoms, it is some times dif-ficult to obtain the unique solution by the conventional method such as Patterson method, heavy atom method or direct method. Incorporating the anomalous scattering information into the direct method would facilitate the solution of the difficulty. This has been proved with a typical known structure.
We analysed double degenerate four-wave mixing (a real time image conversion pro-cess) in uniform plasma. A calculation of necessary pumping energy for the conversion efficiency R=1 shows that process is realizable.
EXCITATION AND INTERACTION OF MULTI-MODE LATTICE VIBRATIONS IN α- LiIO3 CRYSTAL UNDER IRRADIATION OF AN INTENSE LASER
1981, 30 (1): 138-142. doi: 10.7498/aps.30.138
We have observed various spectra of stimulated Raman scattering (STRS) in a-LiIO3 crystal in different scattering geometries under irradiation of an electro-optically Q-switched second harmonic YAG laser. It is shown experimentally that more multi-mode lattice vibrations .can be excited by extra-ordinary incident photons than by ordi-nary ones. We have also observed the first and second order Stokes and anti-Stokes scat-tering lines of E1 mode, which are strong in intensity. The first, second and third order polariton Stokes and anti-Stokes lines are observed, as well as a new spectral line with a frequency shift of 496 cm-1 in anti-Stokes frequency region, which may be attributed to interactions among polaritons with various modes.Fatigue phenomena of Raman activation for the crystal have also been indicated experimentally.
1981, 30 (1): 143-146. doi: 10.7498/aps.30.143
A method of increasing the diffraction efficiency of hologram by using dilute deve-lopment is presented. Characteristic curve of dilute development, relation between the de-veloping time, the exposure and the diffraction efficiency are given. The high diffraction efficiency of three kinds of holographic plates have been obtained.
We have suggested that the extension of SU (m|n) is to SU (l|m|n). We develop a local gauge theory of the graded algebra SU (l|m|n). We find the restrictions on the gauge potentials and matter fields in order that a physically suitable gauge invariant lag-rangian exists. It is natural to extend the graded algebra SU (2|1) electro weak model to include quarks in a superunified model.