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11.
Raouf Sh. Mikhail Suzy A. Selim Farouk I. Zeidan 《Journal of chemical technology and biotechnology (Oxford, Oxfordshire : 1986)》1976,26(4):191-198
The surface properties of a stannic oxide gel and its thermal dehydration products obtained both in vacuo and in the presence of air in the temperature range 100–600°C have been examined by N2 adsorption. Phase and structural changes have been followed by differential thermal analysis and X-ray diffractometry. Complete pore structure analysis showed that samples dehydrated at or below 250°C were microporous. Above 250°C the pores were found to widen with increase of temperature, the widening occurring concurrently with the crystallisation process. Doping with cations of lower valency (Li+ and Al3+) than the host cation (Sn4+) had little effect on the pore structure and specific surface area for the low temperature samples (≤250°), whereas at higher temperatures, e.g. 600°C, it increased the specific area remarkably. The dope ions produce oxygen vacancies and hinder or retard sintering in SnO2. 相似文献
12.
Development of microstructure in four hydrothermal reactions has been undertaken using scanning electron microscopy. These are clinker, clinker-sand, slag-lime and slag-lime-sand hydrothermal reactions. The microstructure of clinker hydration products displayed crumpled foils and tabular masses of calcium silicate hydrates; few cubic crystals of hydrogarnet appeared only during the initial stage of the reaction. In clinker-sand mixture the C-S-H phase was the only product identified. In slag-lime hydration the microstructure displayed both of the hydrogarnet crystals and the C-S-H phase. The hydration of slag-lime-sand mixture (an optimum composition) was associated with the formation of ill-crystallized tobermorite and crystalline 11A tobermorite as the main products. 相似文献
13.
In the course of their small angle x-ray scattering work, Winslow and Diamond also calculated the radius of gyration of the pores. Using its value for a paste, Diamond adopted two models for the average pore: a sphere and a cylinder of equal height and diameter. This model leads to absurd values for the surface area of the paste. Using a cylindrical model, and the radius of gyration plus the hydraulic radius, the present authors calculated for a similar paste the dimensions of the average pore and obtained the values: . The number of pores per gram of paste was 2.26 × 1017. The paper also discusses the surface area of hardened paste, and points out the extremely important contributions of Winslow and Diamond to the subject. 相似文献
14.
Thermal explosions of gaseous media containing inert dust particles are examined. The critical conditions for a thermal explosion are determined using integral manifolds. An asymptotic formula for calculating the critical conditions for thermal explosions with an autocatalytic combustion reaction is obtained.Samara. Translated from Fizika Goreniya i Vzryva, Vol. 29, No. 3, pp. 133–136, May–June, 1993. 相似文献
15.
Kabanov Alexander V.; Klyachko Natalya L.; Nametkin Sergei N.; Merker Steffen; Zaroza Anna V.; Bunik Vita I.; Ivanov Mikhail V.; Levashov Andrey V. 《Protein engineering, design & selection : PEDS》1991,4(8):1009-1017
The size of the inner water cavity of reversed micelles formedin a triple system water-surfactant-organic solventcan be widely varied by changing the degree of surfactant hydration.This gives grounds to use reversed micelles as matrix microreactorsfor the design of supramolecular complexes of proteins. Usingultracentrifugation analysis, it has been demonstrated thatthe oligomeric composition of various enzymes (ketoglutaratedehydrogenase, alkaline phosphatase, lactic dehydrogenase, glyceraldehyde-3-phosphatedehydrogenase) solubilized in reversed micelles of Aerosol OT[sodium bis(2-ethylehexyl)sulfosuccinate] in octane changesupon variation of the degree of hydration. An oligomeric complexforms under conditions when the radius of the micelle innercavity is big enough to incorporate this complex as a whole.At lower degrees of hydration the micelles uncouplesuch complexes to their components. The catalytic propertiesof various oligomeric complexes have been studied. Possibilitiesof using reversed micelles for the separation of subunits ofoligomeric enzymes under non-denaturating conditions have beendemonstrated. In particular, the isolated subunits of alkalinephosphatase, lactic dehydrogenase and glyceralde-hyde-3-phosphatedehydrogenase have been found to be active in Aerosol OT reversedmicelles. The dependences of the catalytic activity of oligomericenzymes represent saw-like curves. The maxima of the catalyticactivity observed at these curves relate to the functioningof various oligomeric forms of an enzyme. The radii of the micelleinner cavity under conditions when these maxima are observedcorrelate with the linear dimensions of the enzyme oligomericforms. Correlation of the position of a maximum with the shapeof an oligomeric complex is discussed. 相似文献
16.
17.
We introduce and solve a problem motivated by integrity verification in third-party data distribution: Given an undirected tree, find a minimum-cardinality set of simple paths that cover all the tree edges and, secondarily, have smallest total path lengths. We give a linear time algorithm for this problem. 相似文献
18.
Moscow Scientific and Industrial Association "Radon." Translated from Atomnaya énergiya, Vol. 77, No. 2, pp. 129–134, August,
1994. 相似文献
19.
20.
I. A. Sobolev S. A. Dmitriev A. S. Barinov O. G. Pol'skii E. A. Turlak M. I. Ozhovan 《Atomic Energy》1995,79(6):840-844
Conclusions The system of regional specialized industrial plants "Radon" was created more than 30 years ago and over this time it has
made it possible to utilize radioactive wastes from industrial and scientific centers in the country. The technology adopted
by the specialized industrial plants for preparing and burying radioactive wastes makes possible safe localization of the
wastes for a long period of time. Investigations designed to estimate the effect of the points of burial by the specialized
industrial plants on environmental objects showed that the technical solutions adopted are reliable.
At the present time the system of regional specialized industrial plants is experiencing difficulties on the legislative,
financial, and technical levels. The system must be reconstructed and modernized. The basis for future decisions will be determined
by the legislative base and the principles which are employed in the process. The optimal path toward modernization of the
regional industrial groups is to produce complexes based on them for collecting, processing, and temporary storage of radioactive
wastes formed within the service zone. The Moscow Scientific and Industrial Association "Radon" is now implementing this concept.
Moscow Scientific and Industrial Association "Radon." Translated from Atomnaya énergiya, Vol. 79, No. 6, pp. 437–443, December,
1995. 相似文献