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961.
962.
This article describes a test piece that minimizes the spread of the results of testing of composite materials on a metal base by extension in the direction of a reinforcing fiber and, from the results, determines the mechanical properties of intermediate and finished products made of these materials.Translated from Izmeritel'naya Tekhnika, No. 10, pp. 39–40, October, 1993. 相似文献
963.
W Matthiessen N Sch?nfeld H Mauch U Wahn A Grassot 《Canadian Metallurgical Quarterly》1993,118(5):139-144
The chest radiograph of a 35-year-old man with fatigue, exertional dyspnoea and haemoptyses revealed a cavity in the left upper lobe and a shrunken left lung with radiolucency greater than that on the right. Acid-fast rods in sputum were identified as Mycobacterium kansasii on culture. Scintigraphy showed a 9% residual perfusion on the left and abnormal ventilation, compatible with Swyer-James syndrome. This had favoured the development of a mycobacterial infection. There was also a decrease in ciliary function (rate of 4-7 Hz, normal: 10-11). Treatment, begun when tuberculosis had been suspected, was after sensitivity tests changed to a combination of rifampicin (600 mg), ethambutol (1600 mg) and protionamide (500 mg) daily. There was marked regression of the findings within 4 weeks, but treatment was prematurely stopped after 11 months. Two years later there was a recurrence which again responded well to the same drug regimen with additional sulphamethoxazole (1600 mg/d). 相似文献
964.
S. N. Syromyatnikov 《Journal of Engineering Physics and Thermophysics》1993,65(2):745-751
Nonlinear spherical vapor bubble oscillations in the main resonance region in a viscous incompressible fluid under the action of a periodically varying external pressure are considered using the multiscale method. Saddle-node type bifurcations that appear when the amplitude or frequency of the external effect changes are investigated.Institute of Thermal Physics of the Ural Branch of the Russian Academy of Sciences, Ekaterinburg. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 65, No. 2, pp. 164–170, August, 1993. 相似文献
965.
Transgenic Tyr-SV40E mice previously produced on the C57BL/6 inbred-strain background, with SV40 oncogenic sequences specifically expressed in pigment cells, are predisposed to melanoma [Bradl, M., Klein-Szanto, A., Porter, S. & Mintz, B. (1991). Proc. Natl. Acad. Sci. USA, 88, 164-168]. Separate lines of these animals differ genetically only in the number of copies and chromosomal site of integration of the transgene. Skin melanocytes from young mice with no apparent skin lesions were established in continuous culture from hemizygous donors with low, medium and high numbers of transgene copies, and from a homozygous offspring of the low-copy mouse line. The standard culture conditions enable C57BL/6 wild-type melanocytes to become stably immortalized without transformation. The transgenic cell lines all changed over time in an orderly progression. However, with greater numbers of transgene copies, the cells more rapidly displayed shorter doubling times, increased anchorage independence, reduced serum and growth factor requirements, decreased tyrosinase expression and melanin content, increased oncogene expression, and capacity to form malignant melanomas when tested by grafting. Melanocytes with the lowest number of transgene copies were of special interest. They grew more rapidly than the wild-type cells from the outset, but did not become tumorigenic until an apparently small number of still-unknown genetic changes had spontaneously occurred, or until the number of transgene copies was increased slightly by homozygosity. In contrast to the hemizygous low-copy cells, the homozygous counterparts underwent striking and rapid transformational changes and early conversion to malignancy. Thus such low-copy transgenic melanocyte lines afford an exceptional opportunity for molecular analysis of somatic genetic evolution toward malignant melanoma. 相似文献
966.
N. A. Samoilov 《Chemical and Petroleum Engineering》2002,38(7-8):437-443
967.
Formulation of the problem of designing the optimal structure of an active system was considered within the framework of the game-theoretical model of interaction of its participants. Solution and the results of studying the control mechanisms in applications such as in-house management and multiagent systems were presented. 相似文献
968.
Egorov G. F. Afanas'ev O. P. Zilberman B. Ya. Makarychev-Mikhailov M. N. 《Radiochemistry》2002,44(2):151-156
Experiments were performed for comparative assessment of the effect of ionizing radiation on the service characteristics of 30% TBP solutions in various diluents: hexachlorobutadiene (HCBD), mixtures of n-paraffins (RED diluent), and fraction of naphthenic hydrocarbons (RZh diluent). The following main parameters were chosen for comparative assessment of the quality of irradiated extractant solutions: composition and behavior of diluent radiolysis products, effect of diluents on the TBP radiolysis, and aggregative stability of emulsions in the main operations of the extraction cycle. The service life of the extraction mixtures was estimated from variation of the above parameters with the irradiation dose. Principles for choosing solvents with increased service life under irradiation were substantiated. 相似文献
969.
Relation between abrasion resistance and flexural strength of high volume fly ash concrete 总被引:2,自引:0,他引:2
In this paper, abrasion of high volume fly ash (HVFA) concretes made with 50% and 70% of cement replacement with fly ash was
assessed in terms of its relation to flexural tensile strength. Comparisons were made between normal Portland cement (NPC)
concrete and fly ash concrete. Comparisons were also made between fly ash concretes. Investigation results have shown that
the abrasion resistance increased as flexural tensile strength increased. Analysis of the results showed that, for concrete
with tensile strength of greater than 4–5 MPa, the abrasion resistance of HVFA concrete with 70% replacement with cement was
found to be higher than that of counterpart control NPC concrete and concrete made with 50% fly ash. The comparison between
the relation of abrasion to compressive strength and abrasion to flexural tensile strength made in terms of R2 of the linear regression showed that a stronger relation existed between abrasion and flexural tensile strength than that
of abrasion to compressive strength of the concrete studied.
Résumé L'étude a pour but d'estimer la relation entre la résistance à l'usure avec la résistance à la traction en flexion des bétons contenant de 50% et 70% de cendres volantes. On a comparé le béton pur au béton contenant des cendres volantes. Des comparaisons ont été faites également entre les différents bétons contenant des cendres volantes. Les resultats de la recherche ont montré que la résistance à l'usure augmente à mesure que la résistance à la traction en flexion de 4∼5 MPa ont une résistance à l'usure plus grande s'ils contienneint 70% de cendres volantes que s'ils étaient purs ou contenaient 50% de cendres volantes. La comparaison entre les relation de la résistance à l'usure en compression et de la résistance à l'usure en traction a été établie en termes de R2 de la régression linéaire. On a prouvé qu'une relation plus forte a été obtenue entre la résistance à l'usure et la résistance à la traction en flexion par rapport à la résistance à l'usure en compression du béton étudié.相似文献
970.