Behavior of Lithium Donors in Bulk Single-Crystal Isotopically Pure 28Si1 –x72Gex Alloys

Semiconductors - The behavior of lithium donors in bulk single-crystal isotopically pure Si1 – xGex alloys (x = 0.0039–0.05) enriched in spinless 28Si and 72Ge isotopes (99.998 and...     

Bistability of hydrogen donors in proton-implanted GeSi alloy

Shallow hydrogen donors (H-donors) were formed in a Ge_{1 − x} Si _x (x = 0.012) alloy by the implantation of low-energy protons followed by heat treatment at 275°C The electrical properties of these donors have been studied using the method of capacitance-voltage characteristics. It is established that a certain fraction of the H-donors exhibit bistability, whereby their concentration changes reversibly when the sample temperature is cycled within 100–200°C. The properties of reversible H-donors in germanium are analogous to those of the bistable H-donors in silicon.     

The influence of the composition of Si–Ge mixed crystals on thermal diffusivity—photoacoustic approach

The paper presents the results of the photoacoustic experiments performed on a series of Si_1−xGe_x samples for x in the range 0–8%. The influence of the alloy composition on the thermal diffusivity and the correlation between the thermal diffusivity and thermal conductivity are presented and discussed.     

Installation of beds and foundations for large-scale oil tanks in the extreme north

Design and structural solutions ensuring the stability of tanks used for the storage of petroleum products with a holding capacity of 50,000 m³ under complex geocryologic conditions are presented. Data on design implementation and results of thermal monitoring and strength tests are cited. __________ Translated from Osnovaniya, Fundamenty i Mekhanika Gruntov, No. 6, pp. 24–28, November–December, 2007.     

Change in composition and porous structure of coal on thermal conditioning

Attention focuses here on methods of coal processing that require minimal quantities of water and yield products that may be effectively used as commercial and secondary raw materials. In the heat treatment of coals associated with semicoking, the accompanying physicochemical transformation of the coal significantly affects its potential for further processing. In semicoking, the filtration system within the coal pieces changes. The initial coal sample contains phytopores of equivalent diameter d_e up to 0.22 μm. More than 54% of these are pores smaller than 10 μm, mainly (65%) of slot and disk form. A small proportion (10%) of supercapillary cavities (d_e > 0.1 μm) is also observed. After heat treatment, the content of small pores is sharply reduced to 10% (450°C semicoke) and 6.6% (550°C semicoke)–that is, almost sixfold–while the content of supercapillary cavities is increased approximately fourfold (in 550°C semicoke).     

Oxygen in Ge:Sn

The effect of doping with tin on the ν ₃ vibrational mode of oxygen in Ge has been studied. The appearance of three new series of absorption lines besides the ν ₃ oxygen vibration spectra was found. The spectrum structure in each series of lines found is similar to the ν ₃ oxygen spectrum structure in Ge. But unlike the ν ₃ mode, the fine structure due to rotational-vibrational interaction of the ν ₃ and ν ₂ modes is not observed and the spectrum structure remains up to temperatures of 130 K. The found three sets of absorption lines are ascribed to the ν ₃ vibration of interstitial oxygen disturbed by tin atoms located in the nearest environment. The assumption has been made that no rotation of oxygen around a Ge-Ge bond for a Ge-O-Ge quasimolecule disturbed by a neighbour Sn atom occurs.