New donor and oxygen precipitate in CZ-silicon are studied by means of Hall measurement, IR measurement and TEM observation. Two types of defect are observed in specimens annealed at 650-750℃, that is, rod-like defects and plate-like defects. New donor generation is mainly related to the plate-like defects, which are indentified as β-cristobalite according to the H-REM results. It is suggested that the new donor originates from the ionization of dangling bonds of silicon atoms on precipitates/matrix interfaces and is controlled by the neucleation and growth of β-cristobalite precipitates.
This paper reports a method of logarithmic straight lines of electron spin resonance (ESR) spectra which has been used to detect the phase transition temperature of Zns:Mn. This experimental analysis gave satisfactory results in the study on influence of trace dope on the phase transition temperature of ZnS crystallite. The difficulty that experiments of X-ray diffraction can not distinguish the phase transition temperatures of ZnS with Mn2+ concentration in the range of 10-3-10-6 gram/gram, had been surmounted.
In this paper, our study on the hydrogen-bond ferroelectrics with Green's function method is reviewed. First we show how to apply the bose-type Green's function method properly to the pseudo-spin model. Then we introduce the four-body interaction in the pseudo-spin model in order to treat the first order phase transition. Analysing the equation describing the phase transition process, we propose a new condition to determine the nature of the system. Also we obtain the critical value of the model parameters and the phase diagram. Our conclusion is that the first order phase transition is induced by the fourbody interaction.
In the paper, we use the theory of orderdisorder transition to calculate the curves of long-range order parameter M vs composition y of B-site ions, and introduce a condition of charge balance between the area within ordering domain and one outside the domain to discuss its growth model with change of the composition y. The theoretical results are in agreement with experiment.
Theoretical analyses of the dependence of apparent fluorescence yield YF on molecular fluorescence quantum efficiency QE and molecular coverage have been made by using ‘Fourlevel' model. The experimental studies of apparent yield YF of SF and Rh6G molecules adsorbed on-chemically deposited silver island film are reported. The experimental results are in agreement with the theoretical expectation.
In this paper, hyper-Raman scattering intensities are calculated based on the quantum theory of radiation. From the intensity formulae, we can conclude directly that all Raman material that has vibration infra-red activity must have vibration hyper-Raman activity simultaneously. Because probability of dipole transition only contributes to anti-Stokes hyper-Raman scattering intensity, the intensity formulae of the anti-Stokes and Stokes are asymmetric, and the former consists of richer spectra than the latter. For the frequency shift of low wave number, the two intensities are almost identical even at room temperature. Finally, the resonance hyper-Raman scattering is also discussed.
The depth profile of interface of Ta2O5/Ta sample has been investigated and a new model to explain the profile data based on the altered layer induced by bombardment of energetic ions during the sputtering has been proposed successfully. The experimental data can be fitted very well and the parameters characteristic of the ion mixing and pile up effect can also be obtained by this model. The samples were prepared by the method of anodic oxidation with a thickness of 500?. All the surface analyses were performed by scanning Auger microprobe model PHI-590 at room temperature. The following results have been obtained: In contradiction with the generally accepted point of view, the depth profile curve dose not exhibit the form of error function. The dominant factor for Auger signal during the interface analysis is the altered layer with a thickness of 30-50? rather than the electron mean free path λ. And the depth profile resolution of interface analysis is determined by compromise between the ion mixing and pile up effect.
In this paper, the spinless Fermi systems with arbitrary band filling have been studied by using the real-space renormalization group methods. For one dimensional case, we obtained the ground state energies, the correlation functions and the relative critical exponents of the systems. The results were compared with those of isotropic s = 1/2 X-Y model. We also discussed qualitatively the correlation fuactions and the related critical exponents for the cases of D>1.
The angular distribution of isotopic sputtering was studied theoretically and experimentally in this paper. A careful experiment was carried out, and a theoretical model was established. The result was that the light isotopes are preferential ejected "normally" and the heavy ones "obliquely". The reason was considered to oe the energy and momentum asymmetry between light and heavy isotopes in the collision cascades. A simple formula of the angular distribution of isotopic sputtering which fits the experimental result is given in this paper.
This paper presents the experimental result of K-shell ionization probability over 2.52 MeV p-wave narrow resonance in the reaction of 56Fe(P, P0)56Fe. The 50% modification of KX-ray emission probability on resonance relative to off resonance has been clearly observed. It indicates that with the ratio UK/Γ as large as 5.3, the interference between the incoming and outgoing target K-shell ionization amplitudes in an atomic collision still exists. From the comparison of calculation based on theoretical formula of Blair and Anholt with the experimental result. The imaginary part of the atomic monopole amplitude Imb0 was deduced and the R0=Imb0/Reb0 was obtained as +1.8.
We apply atomic relativistic self-consisent-field theory to calculate the quantum defects for s, p, d, f and g partial waves for atomic ions with atomic number 2≤Z≤95. The dependence of the quantum defects on the atomic number, ionicity and orbital energy is analyzed. Electronic structure of atomic ions is investigated. Based on this work, the corresponding data base of quantum defects for atomic ions can then be constructed.
The two-dimensional phase retrieval problem involving a non-unitary transform system with liffraction loss has been discussed. By means of our iterative algorithm, the phase distributions of five aberration functions have been recovered with the random distributions as initial input. The phase solutions agree with the true phases perfectly even though a heavy diffraction loss exists.
Nonlinear effects of the gradient inhomogeneity of the magnetic field on the stochastic motion of charged particles due to an electrostatic wave propagated arbitarily relative to the magnetic field are considered in this paper. A sequence of canonical transformations is preformed to obtain a Hamiltonian explicitly exhibiting the possibility of the resonance between the periodic motion of particles and oscillation in the wave. The theoretical analysis shows that, due to the inhomogeneity of the magnetic field, the threshold for the onse of the stochasticity is changed and, in the case of weak inhomogeneity of the magnetic field, it is lowered, which means that the stochasticity appears more easily than in the case of uniform magnetic field.
In this paper, by mean of a quantum-mechanical treatment, we study the interaction of plasma with a coherent electromgnetic field inside a cavity. The eigenstates and eigenvalues of the Hamiltonian of this system is obtained. This eigenstates is the generalized squeezed coherent states. The formulas of the squeezing, anti-bunching, sub-Poisson statistics effects and measured phase operator of the generalized squeezed coherent states is obtained. All of these effects are lime conservative.
Based on MHD concepts, we explain and prove that a self-confined plasma ball imbeded in a constant pressure p0 can be in equilibrium as well as stable states. Besides, it is found that the equilibrium states can not be force-free configurations. The conclusion that the average pressure inside the plasmaball is less than p0 is drawn from the calculation. Furthermore, we point out that the condition for the stability against local perturbations is satisfied, even magnetic shear is weaker in the plasmaball, which implies that the self-confined plasma ball can be expected to have some favourable MHD stability characteristics.
The 1.06 μm laser with irradiance 3.5×1013W/cm2 was injected into Mg microtube target with lateral jet nozzle. The temporal evolution of X-ray spectra emitted from Mg10+ and Mg11+ ion along the side-blow direction was recorded by using X-ray streak camera. The results demonstrate that three-body recombination is the main mechanism to realize the strong population inversion between the excited state energy levels Is4p and Is3p of Mg10+ ion. The electron density in lateral jet nozzle measured by a 2660? UV laser probe coincides with density results deduced from the spectrum information.
The defect configuration relates directly to the mechanical behaviour of structural materials. Especially, dislocation substructure, DSS, is one of the most important configurations. In this paper, a realistic x-ray diffraction profile analysis of DSS, developed by Wang, is reviewed and illustrated. Its application to predicting quantitatively mechanical properties is made.
Target atom excitations in collisions of He+ and He2+ with Li have been studied by optical measurement in the energy range q×(20-150) keV. We have measured Lil 670.8 nm (2p→2s), Lil 610.4 nm (3d→2p), Lil 460.3 nm (4d→2p) and Lil 812.6 nm (3s→2p) emission lines by using an OMA system. The emission cross sections of the observed lines and corresponding Li(2p) excitation cross sections have been calculated. For He+ +Li collision system, Lil 670.8 nm emission cross sections linked well with the results of Aumayr et al. at the low energy points. Our Lil 670.8 nm emission cross sections of He2++Li collision system agrees well with both the theory of Ermolaev er al. and the experimental results of Kadota et al. within the experimental errors.
We have studied the target atom excitations in the collisions of He+ and He2+ with Na in the energy range ot q×(20-140) keV by optical measurements. The Nal 589.0 + 589.6 nm (3p→3s), Nal 818.3nm (3d→3p) and Nal 568.8 nm(4d→3p) lines for He+ + Na collision system have been observed by an OMA system. In He2+ + Na collision system, only Nal 589.0 + 589.6 nm line was observed. The emission cross sections of the Nal lines observed and Na (3p) excitation cross sections are calculated. An obvious effect of coulomb potential of projectile ions on the target excitation has been observed.
The absorption edge of p-Hg1-xCdxTe with x = 0.7 has been measured at different pressures in the range of 0-36kbar and room temperature. The experimental energy gap is basically in agreement with the result calculated by empirical formula The first order pressure coefficient of Hg1-xCdx Te obtained by a least square fitting to experimental data under different pressures is a = 8.7×10-11eV/Pa, which can be explained by chemical bond dielectric function theory. The second order pressure coefficient of energy gap has also been obtained experimentally as β= -6.3×l0-13eV/ kbar which is hard to understand theoretically. In addition, a structural phase transition has been found under 34-36kbar.
The indirect interaction between adatoms are studied by using tight-binding model and one-electron theory. We found that the introduction of impurity atom Cu makes the peak value of the interaction energies to increase, and the introduction of Co makes that value tp decrease. Using the relation between the indirect interaction energies and the relative positions of the adatoms, we explain the structure of H or O monolayer chemisorbed on Ni(l00). In addition, it is found that the interaction energies have a damped oscillation behaviour with the decrease of the coupling strength between the adatoms and the host atoms.
We report the experimental set-up and measurement system combining with a fast-scan Fourier transform spectrometer for photothermal ionization spectroscopy. They have been successfully applied for the investigation and detection of residual shallow impurity centers in ultra-pure germanium and silicon single crystals with high resolution as well as high sensitivity. Boron acceptor at a concentration of the order of magnitude of 108 cm-3 has been detected in ultra-pure germanium, and the detection limit of at least 107 cm-3 has been demonstrated. Lithiumoxygen donor complex D(Li, O) has been revealed in n-type highpurity silicon. Transition line series of both boron acceptor and phosphorus donor in p-type high-purity silicon have been observed simultaneously with the excitation of intrinsic light. In addition, the transitions associated with higher excited states of shallow impurities in both germanium and silicon have also been observed.
In this paper, the threshold of chaos in a forced vibration system with a square nonlinear term is given by using the Melnikov method. The effects of parameters on the threshold are analyzed. The known results obtained respectively by approximate 2-D iterated map and by numerically integrating the differential equation are compared with the results here.
In this paper the effect of gravitational radiation damping on the variation of the orbital elements of binary system is studied using the method of perturbation. This effect results in both the secular and periodic variation of the semimajor axis and the eccentricity, however, the longitude of periastron exhibits no secular variation, but only periodic variation In addition, the deduced expression is applied to calculate the variation of secular and periodic terms of the orbital elements of binary system, Y cyg, PSR 1913 + 16 and PSR 2303 + 24, and the obtained results are discussed and compared with the relativistic effects.
On the basis of general relativity and metric theories of gravity, the expectation to the test in Beijing for anisotropy of the velocity of light was evaluated. The conclusion is that, according to this test, no judgement can be made bewtecn the viewpoint of conventional general relativity and that proposed in ref. .
Presented in this paper are two methods used for determining the critical field strengths in electronegative gas mixtures. One of the two methods is to use the predischarge parameters of the gases for the determination of the mixtures with any concentrations. And the other is to use the recordings of the electron current waveforms in the gas mixtures studied in a discharge chamber. The critical strengths in mixtures of SF6 and N2 were determined by the two methods and good agreement has been achieved.
Quantitative information about tie growth-induced magnetic anisotropy in Y1G was obtained from M?ssbauer spectrum in a previous note. In order to study the origin of this anisotropy, M?ssbauer measurements were extended to low temperatures. We discover that below 170 k, Ku is negative, i-e., there is a spin reorientation. Calculations show that single-ion anisotropy of 0.01/Fe2+ may account for the observed Ku(T), if Fe2+ ions are assumed to occupy preferentially octahedral sites except (1/4 1/4 1/4) and (3/4 3/4 3/4).
Eu3+ ions at different crystal-field sites in SBN crystal are selectively pumped. From the time-resolved fluorescence spectra of 5D0→7F1, the energy transfer rates between ions in non-equivalent sites are evaluated. The dependence of fluorescence peak-frequency on the excitation wavenumber indicates the continuous distortion of local crystal field.