Demercaptanization of Light Hydrocarbon Fractions with Strong Aqueous Ammonia without Producing Sulfur Caustic Wastewater

Theoretical Foundations of Chemical Engineering - A technology for the demercaptanization of light hydrocarbon fractions and liquefied petroleum gas with 25% aqueous ammonia is proposed. One...     

Asymptotic analysis of queues in multiple-access computer networks

The paper considers local-area computer networks with a protocol that supports carrier-sense multiple access with instantaneous conflict detection and is a generalization of slotted ALOHA. An approach based on recurrent processes is applied to analyze the asymptotic behavior of the number of waiting calls under conditions of low retrial rate.Translated from Kibernetika i Sistemnyi Analiz, No. 4, pp. 54–61, July–August, 1991.     

The carcinogenic effect of 5-bromodeoxyuridine and its amplification by x-rays in rats

5-bromodeoxyuridine (BUdR) injected to rats in the neonatal period is shown to produce a pronounced carcinogenic effect which brings about the appearance of various benign and malignant tumours. Exposure of females to X-ray total-body irradiation (1.5 Gy) was followed by intensification of the carcinogenic effect of BUdR. Assuming that this pyrimidine analog reacts solely with DNA substituting thymidine during DNA synthesis and induces point mutations due to tautomerization, the data obtained demonstrate the possibility of tumour induction by a selective DNA perturbation.     

Transport properties of critical dilute solutions

On the basis of the isomorphism of critical phenomena, the behavior of transport properties of binary mixtures in the vicinity of the vapor-liquid critical line is considered. In particular, the renormalization of the singularity of the thermal conductivity in dilute critical solutions has been analyzed in detail. It is shown that the behavior of the thermal conductivity is determined by the critical background, i.e., the fluctuation-induced regular part, which diverges at the critical point of a solvent.     

Two-base numeration systems

Two-base numeration systems are introduced in the paper. They are generalizations of standard numeration systems, which are based on powers of a given radix. The results are reviewed and applications for encoding numbers and trees are given. Further research fields are outlined. A new parallel algorithm for modular exponentiation and new classes of prefix codes are presented.     

Encoding Trees by Linear Recurrence Sequences

A unified encoding of ordered binary trees with integer-valued labels at their vertices is proposed using linear forms of neighboring members of linear recursive sequences of the form P_{n + 2} = a_{n + 2} P_{n + 1} + P, where P₁ = P₂ = 1; a₃ and a₄ … are natural numbers. Encoding and decoding procedures are simply implemented and use the recursive technique of direct pre-order depth-first tree traversal. A brief review of possible applications of the proposed encoding in problems of tree processing and cryptographic symmetric encryption is presented.     

调制电子束在空间等离子体中激发的电磁波辐射

当调制电子束入射进空间等离子体时,由于电子束本征电磁场在非均匀等离子体中的散射(渡越辐射transition radiation)或者电子束的纵向约束性可以产生电磁波辐射.基于这两种辐射机制,研究了半无界调制电子束从航天器入射进平面分层各向同性非均匀空间等离子体产生的电磁波辐射.结果表明,由背景等离子体非均匀性产生的电磁波辐射强度高于由束的纵向约束性引起的辐射强度通过对电子束的适当调制,可以满足辐射电磁波在局部等离子体谐振区域的共振条件,从而增大辐射强度.研究结果可用于对主动空间等离子体试验数据的分析.     

Heuristic Algorithms for Determination of Canonical Forms and Grammatical Characteristics of Words

Algorithms are developed that determine canonic forms and grammar categories from individual words and the vocabulary of a text. Algorithms are proved to be highly efficient. The accuracy of determination directly depends on the length of the text.