排序方式: 共有16条查询结果,搜索用时 15 毫秒
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Kaplunov I. A. Kolesnikov A. I. Kropotov G. I. Rogalin V. E. 《Optics and Spectroscopy》2019,126(3):191-194
Optics and Spectroscopy - The transmission of intrinsic, antimony-doped, and gallium-doped Ge single crystals in the THz spectral range have been experimentally investigated. It is shown that the... 相似文献
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V. A. Kropotov 《Journal of Analytical Chemistry》2001,56(1):60-65
The approximation of titration curves by logarithmic functions was described for the titration of a mixture of two monobasic acids. It was demonstrated with the titration of a mixture of CHCl2COOH, CH2ClCOOH, C6H5COOH, and H3BO3 that this method can be used for the precise determination of equivalence points. The relative error in the determination of titration end-points depends on the values of the corresponding jumps and, to some extent, on the choice of a weight function and lies in the range from 0.1 to 1%. 相似文献
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D. P. Vetrov D. A. Kropotov N. O. Ptashko 《Computational Mathematics and Mathematical Physics》2009,49(11):1972-1985
A method for feature selection in linear regression based on an extension of Akaike’s information criterion is proposed. The
use of classical Akaike’s information criterion (AIC) for feature selection assumes the exhaustive search through all the
subsets of features, which has unreasonably high computational and time cost. A new information criterion is proposed that
is a continuous extension of AIC. As a result, the feature selection problem is reduced to a smooth optimization problem.
An efficient procedure for solving this problem is derived. Experiments show that the proposed method enables one to efficiently
select features in linear regression. In the experiments, the proposed procedure is compared with the relevance vector machine,
which is a feature selection method based on Bayesian approach. It is shown that both procedures yield similar results. The
main distinction of the proposed method is that certain regularization coefficients are identical zeros. This makes it possible
to avoid the underfitting effect, which is a characteristic feature of the relevance vector machine. A special case (the so-called
nondiagonal regularization) is considered in which both methods are identical. 相似文献
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Kaplunov I. A. Kropotov G. I. Rogalin V. E. Shakhmin A. A. 《Optics and Spectroscopy》2020,128(10):1583-1587
Optics and Spectroscopy - The transmission of THz (to 3000 μm) radiation by alkali halide single crystals of sodium chloride (NaCl), potassium chloride (KCl), potassium bromide (KBr), and... 相似文献
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V. A. Kropotov 《Journal of Analytical Chemistry》2000,55(5):449-453
Two possible types of the propagation of random errors in measurements of potential (pH) and the volume of the titrant to
titration parameters determined using logarithmic functions are considered. It is demonstrated that errors in calculated values
are variously related to the errors in initial data. Expressions that provide the estimation of errors in characteristics
of the titration curve from known errors in measurement are obtained. 相似文献
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O. M. Vasil’ev D. P. Vetrov D. A. Kropotov 《Computational Mathematics and Mathematical Physics》2007,47(8):1373-1397
A new approach to the design of fuzzy expert systems is proposed. The representation of knowledge and the formation of statements by fuzzy logic tools are discussed in detail. A model of fuzzy inference is described. Primary attention is given to automatic extraction of knowledge (fuzzy inference rules) from a set of precedents. Various performance criteria for rules are introduced, and an algorithm for their generation (the method of effective restrictions) is proposed. An extension of the type of admissible rules by introducing a fuzzy disjunction operation is described. The possibility of optimizing the rules found is explored. The benefits of the approaches proposed are illustrated by experiments. 相似文献
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A. N. Agafonov M. G. Vlasenko B. O. Volodkin V. V. Gerasimov A. K. Kaveev B. A. Knyazev G. I. Kropotov V. S. Pavelyev I. G. Palchikova V. A. Soyfer M. F. Stupak K. N. Tukmakov E. V. Tsygankova Yu. Yu. Choporova 《Bulletin of the Russian Academy of Sciences: Physics》2013,77(9):1164-1166
Techniques for manufacturing silicon binary (two-level) diffractive lenses and polypropylene kinoform diffractive lenses for the terahertz spectrum range are described. The elements are 1 and 0.8 mm thick, respectively. The silicon lens is manufactured in two versions: with no coating and with a parylene C (polyparaxylylene) antireflection coating. Characteristics of the diffractive optical elements are studied in the beam of a pulse-periodic free electron laser at a radiation wavelength of 141 μm and a repetition rate of 5.6MHz. The radiation resistance of the parylene coating, tested on the Novosibirsk free electron laser, was not impaired when the coating was exposed to an average power density of 4 kW cm?2, the peak power in a 100-picosecond pulse being almost 8 MW cm?2. 相似文献
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Photoconductivity spectra of Ge doped with Sb and P were investigated in a magnetic field (H) at the temperature T = 4.2K. Measurements were performed in the Voigt configuration (H ∥ [111]). Fine structure of lines connected with optical transitions from the ground to the excited states of shallow donors due to spin splitting of impurity energy states were observed. 相似文献