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1.
Triplepass Brillouin spectroscopy was used to detect longitudinal bulk waves generated at a y, z-surface of x-cut quartz. A comparison with Brillouin scattering by thermal phonons shows that Brillouin scattering by induced phonons admit sound attenuation measurements in a dynamic range of almost 80 dB at room temperature. It is also shown that our experimental results agree very well with results obtained at lower frequencies by pulse-echo measurements. 相似文献
2.
R. F. Trunin G. V. Boriskov S. I. Belov A. I. Bykov R. I. Il’kaev G. V. Simakov V. D. Urlin A. N. Shuikin 《JETP Letters》2005,82(5):284-286
The results of experiments on determining the shock-wave compression of initially solid hydrogen (protium) in the pressure range from 17 to 66 GPa are reported. The data have been obtained by using spherical explosive charges. Pressure in samples is created by the impact of a steel striker accelerated to maximum velocities of 23 km/s. Gaseous protium is converted to the solid state using a special cryogenic cooling system. 相似文献
3.
R. F. Trunin G. V. Boriskov A. I. Bykov R. I. Il’kaev G. V. Simakov V. D. Urlin A. N. Shuĭkin 《Technical Physics》2006,51(7):907-918
Experiments on shock wave compression of solid hydrogen (protium) up to 66 GPa and deuterium (in the initially liquid or solid phase) up to 123 GPa using spherical devices where a steel ball (impactor) is explosion-accelerated to 23 km/s are described. The experimental data are compared with those obtained by American researchers for liquid deuterium and protium, who used conventional explosives and light-gas guns as energy sources in the experiments carried out on the Z machine at Sandia National Labs, where an impactor was accelerated by an ultrahigh magnetic field, or on the NOVA laser at the Livermore National laboratory. Our data agree well with those derived by Sandia Labs. 相似文献
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D. Arbeck E. Haussühl L. Bayarjagal B. Winkler N. Paulsen S. Haussühl V. Milman 《The European Physical Journal B - Condensed Matter and Complex Systems》2010,73(2):167-175
The elastic tensor of the tetragonal NiSO4 . 6H2O (retgersite) was measured with a resonant ultrasonic plane parallel plate technique at room temperature as a function of hydrostatic pressure in the range of 0.1-50 MPa and the piezoelastic coefficients have been derived. The monotonic increase in the cij shows that retgersite does not undergo a phase transition in this pressure range. Density functional theory (DFT) based calculations within the linear response method were used to predict the variation of the cij in the range of 1-1000 MPa in the static limit. A comparison of the two data sets shows that while structural parameters and elastic stiffness coefficients are well reproduced by the DFT model, theoretical piezoelastic coefficients of compressible compounds are only in moderate agreement with the corresponding experimental values. The limitations of DFT-based calculations for the calculation of piezoelastic coefficients are discussed. 相似文献
6.
石英拉曼峰进行压力标定的误差研究 总被引:2,自引:0,他引:2
在常温常压下进行了作为压标的石英颗粒的拉曼光谱测量和研究。研究结果发现,在25℃和常压条件下,不同的石英颗粒测得的Si—O振动模在463.59~464.65cm-1范围内变化,误差为(±0.1~±0.3)cm-1。其中不同石英颗粒拉曼峰的最大差异达1.06cm-1,远远大于其测量误差。我们认为这是由于石英破碎时使石英颗粒内产生的应力所致。因此,在进行金刚石压腔高温高压实验的压力确定时,必须以常压下实测的Si—O振动模测量值为零压参考点。另外,拉曼光谱仪的波数漂移以及环境温度的不稳定均会造成不可忽视的压力测量误差,应对此进行校正。 相似文献
7.
Partial breakdown of crystalline silicon dioxide in a pulsed nonuniform electric field is considered. Breakdown channels lie in planes of silicon ions that are parallel to the c axis of the crystal (up to six equivalent directions of the channels are observed). The formation of breakdown channels is satisfactorily described in terms of cascade Auger transitions with regard to the crystallochemical symmetry of the quartz lattice. 相似文献
8.
Secondary ion mass spectrometry is used to determine
- the range distributions of 10–100 keV cesium ions implanted into monocrystalline silicon and
- the cesium profiles in SiO2-Si double layers formed by implantation of cesium into silicon surfaces and subsequently converting the implanted layer into SiO2 through thermal oxidation at 800°C and 1000°C.
9.
Il Nuovo Cimento D - High-resolution a.c. magnetic-susceptibility measurements have been performed on sintered samples of Mg-doped YBCO superconductors YBa2(Cu1−x Mg x )3O7−δ... 相似文献
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M. Houalla F. Delannay B. Delmon 《Journal of Electron Spectroscopy and Related Phenomena》1982,25(1):59-65
The dispersion of NiO supported on boron-modified silicas has been studied by transmission electron microscopy (TEM) and XPS. The TEM experiments showed that all NiO is present in the form of crystallites; values for the dispersion were calculated on the basis of measurements of the size distributions of these crystallites. The XPS measurements were interpreted using a model which assumes large particle sizes and no re-partitioning of the supported species between internal pores and the surface when boron-modification is performed. The variations of dispersion with boron content obtained from this model agree well with the variations measured by TEM. 相似文献
12.
C.A. Duarte G.M. Gusev A.A. Quivy T.E. Lamas J.C. Portal 《Physica E: Low-dimensional Systems and Nanostructures》2006,34(1-2):329
The Shubnikov de Haas oscillations in parabolic well are studied in the tilted magnetic field. The electric field displaces the electron wave function along Z-axis and leads to the strong variation of the average bare g-factor in such system. From the measurements of the filling factor νc at which the spin gap collapse occurs, we deduce the total Zeeman energy, which consists of the bare Zeeman energy and exchange-correlation term. By investigating of the variation of νc in tilted field we reliably extract the bare g-factor as a function of the gate voltage. 相似文献
13.
O.V. Nielsen 《Journal of magnetism and magnetic materials》1981,24(1):81-87
A new method of measurement, which enables a determination of the in-plane anisotropy in magnetic metallic glass ribbons, has been developed. It can be used for materials with the easy axis of magnetization parallel as well as perpendicular to the ribbon axis. The method is based on measurements of the stress dependence of the inhomogeneous magnetization obtained by twisting the ribbon around the ribbon axis. The required experimental equipment is very simple, and the value of the anisotropy constant comes out directly as an equivalent internal stress field. 相似文献
14.
Raman spectra from n-InP samples covering a wide range of concentrations (˜1016 to 1019 cm-3) have been measured. Free-carrier concentrations deduced from the analysis of the upper LO phonon-plasmon coupled modes are compared with values obtained from conventional electrical determinations. It is found that a tight 1 to 1 correlation exists between the results of the two techniques, thus confirming Raman scattering as a powerful analytical tool for the characterization of InP substrates. 相似文献
15.
Oxygen ion diffusion in oxides of the perovskite-type structure was determined by two methods of measurement: i) stepwise
change of temperature or oxygen partial pressure of the gaseous environment of a ceramic sample, and measurement of the relaxation
of electrical conductivity or oxygen content, ii) oxygen permeation through a gas dense oxide ceramic pellet from air to argon.
The experimental problems and sources of errors, calculation methods of chemical diffusion coefficients and oxide ionic conductivities
from these two modes of investigation are discussed. The comparison of relaxation and permeation measurements on 10 oxides
of the type A1−aA′aM1−bM′bO3−σ (A=La, Pr, Ce; A′=Sr, Ca; M=Mn, Fe; M′=Co, Ni) show advantages of the relaxation method in relation to the experimental performance
and possible errors. 相似文献
16.
Optical and luminescence measurements were carried out on Ni2+ doped silver halide crystals. The configurational coordinates of the ground and the first excited states made it possible to explain the important optical properties, such as the Stokes shift between the ground and excited states, the broadening of the bands with temperature and the thermal quenching. Determining the configurational coordinate diagram of the ground and first excited states is the first step for the design and fabrication of solid state and fiber lasers which are based on Ni2+ doped silver halides and which operate in the middle infrared. 相似文献
17.
O. A. Plaksin 《Optics and Spectroscopy》2006,101(4):623-629
The intensity of radiation-induced luminescence and transient optical losses in KU-1 (Russia) and K-3 (Japan) quartz glass optical tibers irradiated in a fast pulsed fission reactor (a pulse duration of 80 μs and a neutron flux up to 7 × 1016 cm–2 s–2) has been measured in the visible range. The intensity of the fast luminescence component nonlinearly depends on the neutron flux. The luminescence intensity and the transient optical losses depend on the probe light intensity. Suppression of radiation-induced luminescence is observed at wavelengths that are longer or shorter than the probe light wavelength. Light probing leads to an increase in transient optical losses and a more rapid recovery of transparency. A model of two photon fluxes is proposed to analyze the relationship of the effects of suppression of radiation-induced luminescence and the increase in optical losses upon light probing. The effect of suppression of radiation-induced luminescence can be used to control the optical properties of fibers in radiation fields. 相似文献
18.
Low-MHz frequency effect on a sonochemical reaction determined by an electrical method 总被引:9,自引:0,他引:9
The frequency effect of low-MHz ultrasound was studied by using the electrical detection method. The experimental data and theoretical analysis results showed that an appropriate frequency value of ultrasound can be chosen to make a sonochemical reaction give its maximum yield according to the distribution of bubbles in liquid. A Gaussian shape distribution of gas bubble radii is to be expected in a water sample with a normal air atmosphere. In addition, the experimental data indicated that comparison of the effect of frequency on the sonochemical efficiency should be carried out under conditions of not only the same sonic power but also the same sonic intensity. 相似文献
19.
Phil Won Yu 《Solid State Communications》1978,27(12):1421-1424
Compensation ratios in high purity epitaxial GaAs layers are determined by Nam et al.'s photoluminescence method at a well-defined finite excitation intensity. This excitation intensity is obtained from the excitation-dependence of the peak energy of the neutral donor-acceptor transition. The values of compensation ratio determined in this way are in excellent agreement with those obtained by the conventional electrical method. 相似文献
20.
M.W. Shafer J.B. Torrance T. Penney 《Journal of Physics and Chemistry of Solids》1972,33(12):2251-2266
Single crystals of EuO have been grown from melts containing excess Eu-metal. i.r. absorption and conductivity measurements were made on these crystals and the results correlated with the crystal growth parameters. It is seen that as the concentration of europium in the initial melt is increased, the growth temperature is lowered and the crystals become richer in europium. The variations in the i.r. absorption and conductivity were studied and are shown to be strongly related to composition. According to the i.r. and conductivity behavior, the EuO crystals can be classified into five types, with compositions ranging from oxygen-rich, to stoichiometric, to europium-rich. The oxygen-rich EuO crystals are insulators and exhibit i.r. absorption which is attributed to Eu3O4 and to Eu3+. Only weak i.r. absorption is seen in the stoichiometric crystals. Those with a deficiency of oxygen show a new i.r. absorption and have either metallic conduction or show large insulator-metal transitions which are attributed to oxygen vacancies. 相似文献