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961.
962.
The shape of the impactor with the maximum depth of penetration (DOP) for a given impact velocity is found using a numerical procedure for solving a corresponding non-classical variational problem. It is shown that the optimum shape in a general case is close to a blunt cone. The variation of the optimal shape of the impactor and the dependence of the DOP vs. the initial (impact) velocity and friction coefficient is studied. The analysis is performed also for optimal conical impactors. 相似文献
963.
The results of a comparative numerical investigation of three types of resonator systems of a cyclotron for acceleration of negative hydrogen and deuterium ions up to maximum energy 30 and 15 MeV, respectively, are presented. It is shown that a vertical system with two half-wave resonators excited in-phase has the smallest active losses and the smallest differential of the amplitude of the accelerating voltage along the edge of the dees and is effective for accelerating particles at dual working frequencies. 相似文献
964.
Andrei Nikolaevich Kolmogorov was the foremost contributor to the mathematical and philosophical foundations of probability in the twentieth century, and his thinking on the topic is still potent today. In this article we first review the three stages of Kolmogorov's work on the foundations of probability: (1) his formulation of measure-theoretic probability, 1933; (2) his frequentist theory of probability, 1963; and (3) his algorithmic theory of randomness, 1965–1987. We also discuss another approach to the foundations of probability, based on martingales, which Kolmogorov did not consider. 相似文献
965.
966.
967.
The results of studying the effect of nontraditional additives, namely, metallic aluminum and zinc powders on the process
of silicate and glass formation using polythermal and thermogravimetric analysis, are described. The specifics of the glass-melting
process for decorative glasses using the nontraditional additives are considered.
__________
Translated from Steklo i Keramika, No. 5, pp. 7 – 10, May, 2005. 相似文献
968.
Ohtsu M. Liou K.-Y. Burrows E.C. Burrus C.A. Eisenstein G. 《Electronics letters》1987,23(21):1111-1113
A problem in frequency-tuning of external-cavity lasers is mode-hopping between neighbouring external-cavity modes. We demonstrate a new interferometric method for monitoring mode-hoping and an automatic control circuit for a 1.3 ?m grating external-cavity laser that maintains single-mode operation when the lasing frequency is tuned. 相似文献
969.
The goal of the PMS project is to produce an environment in which the intelligent online assessment of the design for large-scale ADA programming projects is provided. The focus is on the representation of knowledge about the design process for an individual module. Changes in pseudocode complexity are measured in terms of partial metrics. These metrics can take the designers inferences about the pseudocode program structure into account when assessing module complexity. Next, a model of the stepwise refinement process is given which demonstrates how pseudocode elaboration decisions can be modelled in partial metric terms. Finally, the decisions associated with each refinement step for 17 example refinements taken from the computer science literature are described using partial metrics. 相似文献
970.
Steam volatile fractions obtained from three commercial mayhaw cultivars and two native selections were analyzed by GC and GC/MS. Twenty-four compounds were identified. The nine major components, which comprised 70–80% of the volatile fraction, were hexanal, butyl acetate, (E)-2-hexenal, butyl butyrate, linalool, butyl hexanoate, methyl octanoate, pentyl hexanoate, and hexyl hexanoate. Minor constituents included eight esters, four terpenes, two benzenoid compounds and (E)-2-hexenol. 相似文献