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981.
It was shown for the first time that weighable amounts of uranium dioxide and its mixtures with Np, Pu, and Am in the form of solid solutions can be efficiently and quantitatively dissolved in the presence of tributyl phosphate saturated with HNO3. Individual PuO2 and NpO2 are not dissolved under these conditions. In treatment of a mechanical mixture of UO2 with PuO2 or NpO2, uranium is completely dissolved, while plutonium and neptunium remain in the precipitate. 相似文献
982.
结合工程实例详细介绍了混凝土爆扩桩的成孔、爆扩、混凝土浇筑等施工过程,从施工准备、施工工艺、施工检查及应注意的事项几个方面做了具体阐述,使工程桩达到了设计要求,取得了良好的施工效果。 相似文献
983.
984.
We have studied the effect of spontaneous polarization, which is inherent in noncubic silicon carbide (SiC) polytypes, on the characteristics of quantum wells (QWs) formed in the cubic region at the heterojunction. The analysis is performed for various QW models, including triangular, parabolic, and exponential. Conditions for the appearance of a two-dimensional electron gas at the interface are briefly discussed. 相似文献
985.
Electrooptics and dynamics of twisted nematic-cholesteric liquid crystal (LC) droplets occurring in an isotropic environment in a dc electric field have been studied. The twist of the LC director field significantly influences the character of rotation of the cholesteric droplets. The most probable mechanism accounting for the rotation of cholesteric droplets is related to the Carr-Helfrich electrohydrodynamic instability. 相似文献
986.
A generator of Xe radionuclides was developed. These isotopes are required to calibrate automatic installations used for determining
noble gases at international stations of radionuclide monitoring. The results of purging a generator containing 0.1 μg of
252Cf are reported.
Original Russian Text Yu.V. Dubasov, N.V. Skovorodkin, E.I. Biryukov, 2007, published in Radiokhimiya, 2007, Vol. 49, No.
3, pp. 262–263. 相似文献
987.
Carbon-based nanoparticles synthesized by heat treatment of nanodiamond in the temperature range of 1000–1900 °C were added to PTFE film to investigate the structural effect of the carbon particles on the tribological properties of PTFE composite film. Carbon-based nanoparticles were prepared by milling with micron sized beads in chemically treated water before their addition to PTFE film. The wear and frictional properties of PTFE nanocomposite film were measured by the ball on plate type wear test. The wear resistance of PTFE film was found to be enhanced by the addition of 2 wt% of carbon nanoparticles. The wear coefficient of PTFE film was decreased from 16.2 to 3.5 × 10−6 mm3/N m by the addition of carbon-based nanoparticles heat-treated at 1000 °C. Increasing the heating temperature of the nanodiamonds caused the extent of aggregation and particle size to increase. The wear resistance of PTFE nanocomposite film was enhanced by the addition of nanodiamonds heat-treated at 1000 °C, but decreased when the heat treatment temperature of carbon nanoparticles was further increased. Tribological behavior of PTFE nanocomposite films depending on the types of carbon nanoparticles were explained based on the structural, physical and chemical modification of carbon nanoparticles. 相似文献
988.
Experimental data obtained by atomic force microscopy showing that a carbon deposit formed during graphite spraying in an electric arc possesses a fractal structure. The deposit is composed of clusters with dimensions on the order of 1–5 nm. The surface and profile of the deposit exhibit a self-affine fractal structure. The fractal dimensions of the deposit surface and profile, as well as the Hurst index characterizing the self-affine fractal, are determined. 相似文献
989.
990.
E. Yu. Afanas’eva 《Technical Physics Letters》2007,33(3):258-260
Thermodesorption of samarium (Sm) atoms and samarium oxide (SmO) molecules from samarium films deposited in vacuum onto tungsten substrates covered with thin (<1 nm thick) layers of tungsten oxides has been studied. It is established that samarium reduces tungsten from its oxides. The parameters of Sm and SmO desorption from an oxidized tungsten surface are determined. 相似文献