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991.
A novel microwave imaging technique based on the generalised weighted backprojection operator is introduced and tested using experimental data. Images of the internal structure of penetrable objects using this technique are compared and contrasted with images found from the classical back-projection method. It is demonstrated that the new method provides high-quality images of both discrete and continuous internal structure without the distortions characteristic of traditional methods.  相似文献   
992.
A failure assessment diagram is derived from carbon-manganese steel compact tension specimens. The diagram has been determined from an elastic-plastic finite element analysis of a compact tension specimen geometry. The diagram has been validated by using experimental fracture toughness data obtained on the same steel and specimen geometry modelled in the finite element analysis. The plastic collapse load has been determined empirically for this geometry.It is shown that a non-work-hardening failure assessment diagram is not a good representation of the experimental data and that the computed failure assessment diagram is more appropriate for describing the behaviour of the carbon-manganese steel specimens.  相似文献   
993.
In this review we have summarized the iron bioavailability literature dealing with protein (or major dietary protein source) effects and proposed a mechanism for these effects compatible with existing empirical data. Data from studies employing a variety of approaches are fairly consistent in showing that meats enhance non-heme iron absorption while plant, milk and egg proteins depress it. The variable, and sometimes opposite, effects of different proteins on iron bioavailability may be explained by the following proposed mechanism: (1) protein enhances iron bioavailability by releasing peptides during digestion which form soluble, low molecular weight complexes that readily release iron to mucosal receptors; (2) protein depresses iron bioavailability by releasing peptides which form insoluble complexes with iron or which form soluble complexes that do not release iron to mucosal receptors. Data from the literature, including our own evidence, which support the above hypothesis are discussed.  相似文献   
994.
A study was made of energy expenditures and factual nutrition of the workers engaged in synthetic leather manufacture. Antropometric measurements were also taken. Based on the study of daily energy expenditures, the calculations were made of the optimal requirements of the main substances and energy. The actual nutrition of the workers was found to provide the necessary caloricity covering energy expenditures. However, definite shortcomings were revealed in the structure of the foods consumed, namely insufficient intake of vegetable fats, the prevalence of simple sugars in the structure of carbohydrate component, insufficient intake of vitamins A, B1 and folacin. According to the antropometric measurements 30,4% of the examined workers were obese.  相似文献   
995.
996.
997.
The method of proton magnetic resonance is used to determine the melting point of ice particles in the pores of monodisperse porous glasses ranging from 10 to 1000 Å in radius.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 48, No. 3, pp. 461–466, March, 1985.  相似文献   
998.
An approach to the reconstruction problem of undistorted images of objects observed through randomly inhomogeneous media is considered. The approach is based on the solution to the integral equation of the first kind (convolution equation) with an unknown kernel and inaccurately defined right-hand side. It is demonstrated that the procedure for the construction of an inverse operator needed for the solution is determined by the minimization of the nonlinear regularizing multiextremum functional, which takes into account the a priori data regarding the positive intensity distribution in the image of an object. The analysis of the structure of the multiextremum functional is presented. The estimates of the reconstructed images that correspond to the global and local extrema are studied. The results of a numerical experiment on the reconstruction of the optical image of an object observed through the turbulent atmosphere are presented.  相似文献   
999.
1000.
The threshold for hypoxia effects on perceptual-motor performance   总被引:3,自引:0,他引:3  
  相似文献   
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