On Optimal Signal–Filter Pairs

We extend the notion of an optimal signal–filter pair to the case where n-convolution is used instead of cyclic convolution. We construct n-optimal n-adic signals for all n = 2, 3, . . ..     

Acute appendicitis complicated by destruction of the large intestine and septic shock

Access and visualization in the implant-abutment area are often compromised. Tissue impingement and lack of abutment position verification may result in inaccurate fit.     

Analysis of instantaneous cardiac rhythm in a model of multifractal dynamics based on Holter monitoring

For the specific analysis of the variability of RR intervals of the cardiac rhythm, a method for measuring the instantaneous cardiac rhythm (ICR) represented by a multifractal dynamical model (MDM) has been developed. The advantages of this method, compared to the statistical methods of analysis of the RR intervals used, have been demonstrated. The method allows possible catastrophes of the cardiovascular system to be predicted. Using the data of Holter monitoring and the program system developed, we have plotted ICR curves, an ICR piecewise linear trend, and variability charts for three randomly chosen time intervals. The self-similarity (fractality) of the ICR up to an accuracy of 5% has been shown based on the explicit data. The MDM parameters have been calculated based on the ICR data. The analysis of the dynamics of these parameters has been conducted and their compliance with the status of the patient examined has been studied. The relevance of the ICR examination within MDM is closely related to the necessity of recognizing new markers of adverse cardiovascular episodes. The research performed shows that the results obtained could be taken as a basis for developing a new mathematical method of ICR examination based on Holter monitoring.     

Investigation of the iodine component composition in helium for the conditions of a HTGCR

Scientific-Research Physical Chemistry Institute. All-Union Scientific-Research Institute of Automatic Machinery. Institute of Nuclear Reactors, Russian Scientific Center "Kurchatovskii institut." Translated from Atomnaya énergiya, Vol. 76, No. 2, pp. 148–151, February, 1994.     

Photodecomposition of hexachlorobiphenyl by radiation of a KrCl (222 nm) barrier-discharge excilamp

The process of dechlorination of 2,2′,4,4′,5,5′-hexachlorobiphenyl (PCB 153) under the action of UV radiation of a KrCl* (222 nm) barrier-discharge excilamp has been studied. The photolysis was performed in PCB 153 solutions in hexane with concentrations of 10 μg/ml (sample 1) and 1 μg/ml (sample 2) and in a PCB 153 film on a silica plate (sample 3). The degree of PCB 153 decomposition was determined using the optical transmission spectra measured in a 185–350 nm wavelength range. An analysis of these spectra showed that chlorine atoms in ortho 2,2′-positions are detached first. At a UV radiation intensity of 3 mW/cm² on the sample surface, the residual PCB 153 content in samples 1–3 was below 2% (60-min exposure), below 3% (25-min exposure), and below 20% (60-min exposure), respectively.     

Formation of an iron-containing catalytic nanoparticle during the three-phase Fischer–Tropsch synthesis: Molecular modeling

The effect of a polyacrylonitrile additive on the catalytic behavior of an iron-containing suspension under the conditions of Fischer–Tropsch synthesis in a slurry reactor is studied. Modeling of the formation of a catalytic particle using the molecular dynamics method is performed.     

Multiparametric gyrotron power control during microwave processing of materials

Optimization of the control of gyrotron generation regime through consistent variation of the cathode voltage and solenoid magnetic field makes possible a significant (up to threefold) decrease in power consumption during microwave processing of materials. It is experimentally established that, for this purpose, it is possible to use fast (with a characteristic time on the order of a fraction of millisecond) modulation of microwave power through variation of the working magnetic field by the current of an auxiliary coil arranged near the cavity.     

Method for calculating the spectrum of scattered photons under conditions of aerialγ-mapping

An analytical method for calculating the spectrum of multiply scattered γ-radiation of radioactive isotopes distributed in soil is proposed. Expressions for intensities of fluxes of photons scattered n times are obtained in the form of sums of multiple integrals of a simple form. The integration is performed numerically. Results of calculations of test examples are presented. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 71, No. 3, pp. 551–558, May–June, 1998.