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1.
V. A. Eremenko V. N. Karpov V. V. Timonin N. G. Barnov I. O. Shakhtorin 《Journal of Mining Science》2015,51(6):1113-1125
The authors have determined the causes of drop in performance of induced block caving using fans of blastholes 105 mm in diameter and single blastholes 250 mm in diameter, as well as the sources of increased drilling cost and expansion of start-up time of production blocks in Abakan underground mine. Alternatives of improvement in drilling efficiency under current conditions are discussed. 相似文献
2.
V. Yu. Karpov 《Materials Science》2007,43(5):746-749
We developed a new type of porous materials with anisotropic structure based on a large number of metals. It is shown that
these material, called gasars, have properties different from the properties of the other porous materials. Thus, the strength
of gasars is much higher than the strength of powder materials with the same porosity and their impact toughness is readily
regulated by the sizes of the pores. The internal structures of gasars and possible versions of the types of pores in these
materials are strongly diversified, which makes the spectrum of their possible applications very wide. We discuss some specific
directions of the potential applications of gasars. The results of measurements of the thermal conductivity of gasars and
monolithic specimens are presented. It is shown that, for a certain level of porosity, the specific thermal conductivity of
gasars is higher than for monolithic materials. We also make some basic conclusions concerning the characteristics of new
porous materials.
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Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 43, No. 5, pp. 125–127, September–October, 2007. 相似文献
3.
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5.
Translated from Khimicheskoe i Neftyanoe Mashinostroenie, No. 1, p. 32, January, 1992. 相似文献
6.
The possibility that progesterone or estradiol may regulate expression of G protein in the rat myometrium during the course of pregnancy has been investigated using 1) immunoblot analysis of Gi2 alpha, Gi3 alpha, and Gq alpha subunits and 2) hybridization blot analysis of subunit mRNA. Eighteen hours after administration, estradiol had significantly increased the levels of both Gi2 alpha subunit and Gi2 alpha mRNA (by 40% and 32%, respectively). In control pregnant rats, we observed similar changes at the end of pregnancy, when myometrial concentrations of estradiol had increased, i.e., a 41% increase in immunoreactive Gi2 alpha subunit that correlated with a parallel 45% increase in mRNA levels. In contrast, levels of immunoreactive Gi3 alpha subunit and mRNA, which decreased with advancing gestation, were not influenced by estradiol or progesterone administration. Progesterone administration resulted 30 h later in a significantly decreased level of Gq alpha immunoreactivity (32%) and Gq alpha mRNA (30%). In control rats, Gq alpha protein and mRNA were also significantly lower at midpregnancy under progesterone dominance vs. term. At this stage, a twofold increase in Gq alpha subunit correlated with a 40% increase in mRNA levels. These results demonstrate that myometrial Gi2 alpha and Gq alpha subunits are physiological targets for estradiol and progesterone, respectively, in vivo. Alterations of these G protein levels are discussed in relation to their mediating effects on adenylyl cyclase activity or the phospholipase C pathway during the course of pregnancy. 相似文献
7.
V. V. Ruzhyts’kyi H. D. Tolstoluts’ka S. O. Karpov I. E. Kopanets’ H. M. Malyk 《Materials Science》2007,43(5):735-741
By the methods of thermal-desorption spectrometry and nuclear reactions, we study the processes of trapping, thermal desorption,
and evolution of the profiles of distribution of deuterium ionically implanted with an energy of 12 keV into Kh18N10T steel
at room temperature. The evolution of the microstructure of steel under the conditions of irradiation of samples with D2+ ions up to doses of 1 · 1018 D/m2−2 · 1022 D/m2 is studied by the method of electron microscopy. The regularities of changes in the mechanical properties of steel after
irradiation are determined.
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Translated from Fizyko-Khimichna Mekhanika Materialiv, Vol. 43, No. 5, pp. 117–121, September–October, 2007. 相似文献
8.
A. O. Karpov 《Cybernetics and Systems Analysis》1992,28(3):451-468
The inverted structure is proposed as a relational model of the information kernel in diagnostic and expert systems. The inverted structure can be used for identification of stored data by collections of attributes. The properties of the join operation on partially defined relations and issues of semantic integrity of data are discussed.Translated from Kibernetika i Sistemnyi Analiz, No. 3, pp. 144–164, May–June 1992. 相似文献
9.
Evaluation of humoral immune responses in cattle grazing endophyte-infected or endophyte-free fescue
RL Rice DJ Blodgett GG Schurig WS Swecker JP Fontenot VG Allen RM Akers 《Canadian Metallurgical Quarterly》1997,59(3-4):285-291
Anecdotal reports suggest cattle with fescue toxicosis may not respond to vaccination and thus, experience increased incidence of Bovine Respiratory Disease Complex (BRDC) when shipped to feedlots. Fescue toxicosis causes hypoprolactemia in cattle. Hypoprolactemia decreases humoral immune responses in mice. Therefore, a study was conducted to compare the magnitude of primary and secondary humoral immune responses against specific antigens in cattle grazing endophyte-infected or endophyte-free fescue. Angus steers were blocked by weight and allocated into four groups. Two groups grazed endophyte-infected (EI) fescue and the other two groups grazed endophyte-free (EF) fescue. All steers were injected IM on d 0 and 21 with lysozyme without adjuvant and concanavalin. A (Con A) with sheep red blood cells (SRBC) in incomplete adjuvant of Freund. Steers were bled on days 0, 21 and 35 post-vaccination. Average daily gains (ADG), alkaline phosphatase (ALP) activity, cholesterol concentrations, rectal temperatures, and serum prolactin concentrations were measured to confirm fescue toxicosis in steers grazing EI fescue. Antibodies to Con A and SRBC were determined by ELISA and hemagglutination assay, respectively. The ADG were decreased for the EI group during the first month. Rectal temperature were elevated and serum prolactin concentrations were decreased in the EI group. Cholesterol and ALP concentrations also were decreased in the EI group. Primary and secondary immune responses against Con A tended to be increased and were increased against SRBC in the EI group. Antibodies against lysozyme were not induced in either group. In conclusion, cattle grazing EI fescue mounted similar humoral immune responses to vaccination, despite hypoprolactemia, as cattle grazing EF fescue. Increases in bovine respiratory disease in cattle maintained on EI fescue probably is not associated with lack of humoral immune response to vaccination protocols as a result of fescue toxicosis. 相似文献
10.
Three models of cancerogenesis were used to test the anti-cancerogenic effects of pentoxiphylline. In female rats, breast adenocarcinoma was induced by intramammary injections of N-methyl-N-nitrosourea (MNU) or colonic and rectal adenocarcinomas by intrarectal instillations of MNU. In female mice, squamous cell carcinomas of the cervix uteri and vagina were induced by intravaginal applications of 7,12-dimethyl-benz(a) anthracene (DMBA). Pentoxifylline was given with drinking water at a concentration of 500 mg/l long at the stage of carcinogenesis promotion/progression. Pentoxifylline exerted a strong inhibitory effect on the development of mammary tumors and a moderate inhibitory effect on the development of colonic and rectal tumors induced by MNU in rats. However, the drug did not affect the development of cervical and vaginal tumors caused by DMBA in mice. 相似文献