Ga Doping of Thin PbTe Films on Si Substrates during Growth

In depositing thin PbTe films onto Si substrates by a modified hot-wall method, Pb_{1 – x} Ga _x melts were used as Ga vapor sources in combination with separate Pb and Te sources. Data on the vaporization behavior of Pb_{1 – x} Ga _x melts were used to devise a new technique for reproducible growth of PbTe/Si and PbTe/SiO₂/Si structures. The lattice parameter of the PbTe films was found to vary nonmonotonically with Ga content, which was interpreted as evidence that the dopant can be incorporated by different mechanisms. Conductivity and Hall effect measurements between 77 and 300 K reveal a nonmonotonic variation of carrier concentration with doping level and suggest that Ga is an amphoteric impurity in narrow-gap IV–VI semiconductors.     

Self-intersection elimination in metamorphosis of two-dimensional curves

H :[0, 1]× ³→ ³, where H(t, r) for t=0 and t=1 are two given planar curves C ₁(r) and C ₂(r). The first t parameter defines the time of fixing the intermediate metamorphosis curve. The locus of H(t, r) coincides with the ruled surface between C ₁(r) and C ₂(r), but each isoparametric curve of H(t, r) is self-intersection free. The second algorithm suits morphing operations of planar curves. First, it constructs the best correspondence of the relative parameterizations of the initial and final curves. Then it eliminates the remaining self-intersections and flips back the domains that self-intersect.     

Interaction of a Leak Molecular Flow with a Microfiber Sensor Considering Size Effect

The dynamic effect of a free molecular effusion-type flow from a leak on a microfiber sensor in the form of a spherical conglomerate of equiprobably spatially oriented fibers with their low volume concentration has been studied. An estimate of how the size effect (the ratio of the microfiber sensor radius to a characteristic linear dimension of the problem) influences the sensor dynamics is provided.     

Effect of Grain Size on the Thermal Expansion of Isotropic Synthetic Graphites

The relationship is analyzed between the thermal expansion coefficient of synthetic graphites and the grain size of their filler. It is shown by examining a large number of commercial graphites of different classes that their thermal expansion coefficient increases from 2 × 10⁻⁶ to (7–8) × 10⁻⁶ K⁻¹ as the grain size decreases from 3000 to 1 μm. The strength of synthetic graphites also increases with increasing grain size and correlates with thermal expansion. The likely reason for the increase in thermal expansion coefficient is the better contact between neighboring microvolumes of the material. A model is proposed for the thermal expansion of synthetic graphites which considers microvolumes 0.1 to 0.5 μm in size, with a thermal expansion coefficient on the order of 8.3 × 10⁻⁶ K⁻¹, only a fraction of the microvolumes being involved in thermal-expansion transfer. The fraction of such microvolumes decreases with increasing grain size. __________ Translated from Neorganicheskie Materialy, Vol. 41, No. 12, 2005, pp. 1456–1462. Original Russian Text Copyright ? 2005 by Samoilov, Shilo.     

VVÉR-1000 TVSA fuel assembly: Direction of development and operating results

The structural and main characteristics of an alternative fuel assembly TVSA VVéR-1000 are examined. The results of experimental validation, reactor tests, and operation are presented. The main directions of structural improvements of the assembly and VVéR-1000 fuel cycles based on the improved TVSA are discussed. __________ Translated from Atomnaya énergiya, Vol. 102, No. 1, pp. 43–48, January, 2007.     

The Al-containing wastes technology of recycling for alumina, coagulants and building materials production

The Al-containing wastes are generated by a row of industrial plants as hydroalumocarbonate residuum, underwastes water, foundry slag, mud, catalysts, mineral part of coals and others. These wastes is cycling in technological processes that cause to extra energy costs, processes stages difficulties and negatively affecting to environment.     

Thermal crosstalk in a group of pyroelectric sensitive elements for thermal imaging

Temperature distributions under periodical thermal excitation and the response of the thermal imaging device, composed of the group of pyroelectric sensitive elements mounted on a single silicon substrate, are presented. The sensitive element consists of a covering metal layer, infrared polymer absorber, front metal contact, sensitive pyroelectric element, the interconnecting column, and the bulk silicon readout. The results of numerical modeling show that the thermal crosstalk between sensitive elements to be critical especially at low frequency (f<10 Hz) of periodically modulated light.