Efficient silicon light-emitting diode with temperature-stable spectral characteristics

The influence of temperature on the parameters of the band-to-band emission spectrum of a light-emitting diode based on single-crystal silicon was investigated; the unprecedentedly high stability against variations in temperature was observed for both the electroluminescence intensity at the peak of the spectral distribution (I _EL ^m ) and the wavelength corresponding to this peak (λ_m). The internal quantum efficiency of the light-emitting diode at room temperature is estimated as no lower than 0.1%. The value of I _EL ^m varies by no more than ～10% as the temperature is varied from 120 to 300 K. The value of λ_m remains virtually constant in the temperature range of 200–300 K. The unprecedentedly high stability of λ_m is related to interference effects in the oxide film through which the radiation of the light-emitting exits. It is shown that one of the important factors that govern the temperature stability of I _EL ^m is a decrease in the lifetime of the minority charge carriers with decreasing temperature.     

Solubility of UF4, ThF4, and CeF3 in the NaF-ZrF4 melt

The solubility of UF₄, ThF₄, and CeF₃ in a fluoride melt 52 mol % NaF-48 mol % ZrF₄ in the temperature range 550–750°C was studied. The solubility of the fluorides in the melt increases with temperature. At 600°C and higher temperatures, the solubility decreases in the order UF₄ > ThF₄ > CeF₃. The temperature dependences of the solubility of UF₄, ThF₄, and CeF₃ in the NaF-ZrF₄ system are satisfactorily described by a linear equation.     

Structural changes during annealing of deformed Pd-25 at % Ni Alloy

X-ray diffraction analysis and residual resistivity measurements are used to study the short-range order and fine crystal structure of the Pd-25 at % Ni solid solution deformed at room temperature and their changes during isochronous annealings. A short-range order was shown to exist in the deformed alloy; the structure of the order does not correspond to the L1₂ superstructure. During the annealing, the character of the order remains unchanged. Possible physical processes that cause the nonmonotonic changes in the short-range order, fine crystal structure parameters, and residual resistivity are considered.     

电磁干扰滤波器综述

选择这些器件需要确定干扰的类型和来源,及其适用的标准 现在生产的所有电子设备都包含电磁干扰滤波电路.同样,所有开关型电源都有内部的电磁干扰滤波器.但是,在有些环境中,这些电子器件的电磁干扰滤波器需要辅助滤波器,以便满足更加苛刻的电噪声管制或者保护器件免受过多的外部噪声源干扰.     

High-shrinkage-potential porous glass-ceramic supports for high-temperature oxide ceramic membranes

We have optimized the composition of porous glass-ceramic supports compatible with conducting ceramics and have developed a procedure for the fabrication of such supports. High-shrinkage-potential porous supports in the form of dead-end tubes have been shown to be best suited for designing multilayered selective ceramic membranes. We have assessed the effects of various modifiers on the shrinkage curve of such supports. The factors that play a central role in determining the properties of supports have been identified: the amount of burnout additives determines the macroporosity, the addition of low-melting clay influences the shrinkage potential, leaching influences the microporosity, impregnation with a lanthanum salt determines the shape of the shrinkage curve and reactivity, and modification with Al₂O₃ sol determines the heat resistance of the supports.     

Segments on bit-mapped graphics displays

The problems associated with using picture segments in interactive applications on workstations with bit-mapped displays are discussed. A method for displaying and updating segments is introduced.     

Processes and character of melt loading by electrodischarge generator of vibrations on resilient elements: Part II (Propagation of disturbances)

On the basis of numerical modeling of hydrodynamic processes occurring in melt under electrohydropulse treatment, the field of pressures in liquid metal at the postdischarge stage is calculated. It is shown that the application of waveguide attachments allows increasing the pressure levels at the initial stage of treatment, the share of energy being dissipated in the melt, and the cavitation duration. It is determined that the efficiency of treatment is stipulated by the geometrical size correlation of a working element and a ladle.     

Effect of <Emphasis Type="Italic">d</Emphasis>-metal hydroxides on water dissociation in bipolar membranes

Methods of electrochemical impedance, voltammetry, and ion transport numbers are used to study bipolar membranes that contain hydroxides of transition metals on the bipolar boundary. It is shown that the introduction of hydroxides significantly increases the rate of water dissociation in bipolar membranes, and the catalytic activity of transition metal compounds depends on the nature of the metal. It was found that the pseudounimolecular rate constants of the rate-limiting steps of dissociation calculated from the thermodynamic and kinetic data are two orders of magnitude higher than the effective constants derived from experiment. This suggests that only a small fraction of the surface of metal hydroxide particles is in the space-charge region (bipolar region), in which the dissociation of water molecules occurs in high-intensity electric fields.