A method of organizing iteration loops in calculating dynamic modes of large electronic circuits based on a decomposition of the modeled circuit into subcircuit components is considered. This method ...considerably reduces the time required for the interaction of system’s users with the network, so the efficiency of the used software is improved significantly, which is especially important for the construction of service-oriented computer-aided design systems.
A fast numerical algorithm for calculating the given instability of the zero level of DC amplifiers is considered. Traditional methods for calculating the instability of nonlinear electronic circuits ...require repeated calculations of the stationary mode of the simulated nonlinear circuit, followed by the calculation of the sensitivity of the values of the coordinates of the operating points to variations in the parameters of the components. In contrast to them, the method proposed in this article is based on performing a single linearization of the nonlinear characteristics of the components only at the initial stage of solving the problem. At the subsequent stages of solving the problem, the linearized representation of the components is used to calculate the given instability under the influence of external influences and the technological spread of parameters during the serial production of the developed circuit.
—The definitions of the critical contact and critical energy coordination number (CECN) of a molecular crystal are introduced. Some characteristics of the critical contact in the diagram of ...intermolecular interaction energies are discussed. The molecular coordination number (MCN) and critical coordination number (CCN) in a series of crystalline structures of homomolecular monosystem aliphatic α,ω-diols are calculated.
Background and Objective
Epidemiological data obtained during the ongoing SARS-CoV-2 pandemic suggests that COVID-19 mortality has specific age and gender associations. However, limited ...epidemiological studies explored specific populational risk factors, including comorbidities, and patient clinical characteristics. The main aim of our retrospective cohort study was to analyze associations between age, gender, and comorbidities in deceased COVID-19 patients.
Materials and Methods
A retrospective cohort analysis was performed to assess significant risk factors in adult patients deceased from COVID-19 infection by evaluating Electronic Medical Records and post-mortem analysis in COVID-19 patients deceased between April 2020 to October 2020. All patients underwent post-mortem evaluation along with medical history analysis, including data on disease duration, hospitalization, and clinical peculiarities.
Results
Medical records of 1487 COVID-19 patients revealed that the prevalence of males was higher (by 23%) than females; the median age for males was 71 years of age whereas for females it was 78. The most prevalent comorbid pathologies were: hypertension, obesity, diabetes, and cancer. Males are at significantly increased risk of lethal outcome, even in younger age groups, with comorbid conditions.
Conclusion
The study concluded that comorbidities, such as hypertension, obesity, diabetes, cancer are the most important risk factors for comorbid mortality in COVID-19 patients. In addition to lung damage, multiple organ dysfunctions may be a crucial reason for COVID-19 induced death. Special precautions, such as early hospitalization, increased monitoring, and preventative tactics should be taken for at-risk patients.
The results of the first observations of solar sporadic radio emission within 10 – 70 MHz by the
Giant Ukrainian Radio Telescope
(GURT) are presented and discussed. Observations in such a wide range ...of frequencies considerably facilitate the registration of harmonic pairs. The solar U-burst harmonic pair observed on 8 August 2012 is analyzed. The burst key features were determined. Among them, the time delay between the fundamental and harmonic emissions was of special interest. The fundamental emission was delayed for 7 s with respect to the harmonic emission. A model for explaining the occurrence of such a delay is proposed, in which the emission source is located inside a magnetic loop containing plasma of increased density. In this case, the delay appears due to the difference in group velocities of electromagnetic waves at the fundamental and the harmonic frequencies.
We present a comprehensive comparison of the catalytic evaluation of a FeNC catalyst using two different approaches, i.e., employing the rotating ring disk electrode (RRDE) technique and a gas ...diffusion electrode (GDE) setup. With both techniques, the FeNC catalyst is evaluated in acidic as well as in alkaline environment. The oxygen reduction reaction (ORR) is studied and parameters such as ORR kinetic activity, Tafel slope, and the apparent activation energy are determined at different applied temperatures/overpotentials. The obtained results offer clear evidence that in alkaline medium, the GDE offers reaction conditions with improved reactant mass transport enabling an evaluation of the FeNC catalyst closer to membrane electrode assembly (MEA) testing. As compared to the RRDE evaluation, the ORR rate is higher in the GDE setup and the potential range for extracting kinetics and activation energies is substantially improved. However, in acidic environment only minor differences between the two reaction environments (RRDE and GDE) are observed. The difference between alkaline and acidic conditions is rationalized based on the different reaction pathway in the two environments.
FeNC catalysts are promising substitutes of platinum‐type catalysts for the oxygen reduction reaction (ORR). While previous research disclosed that high pyrolysis temperatures are required to achieve ...good stability, it was identified that a trade‐off needs to be made regarding the active site density. The central question is, if a good stability can also be reached at milder pyrolysis conditions but longer duration retaining more active sites, while enabling the defect‐rich carbon to heal during a long residence time? To address this, a variation of pyrolysis temperatures and durations is used in FeNC fabrication. Carbon morphology and iron species are characterized by Raman spectroscopy and Mössbauer spectroscopy, respectively. Fuel cell (FC) activity and stability data are acquired. The results are compared to ORR activity and selectivity data from rotating ring disc electrode experiments and resulting durability in accelerated stress tests mimicking the load cycle and start‐up and shut‐down cycle conditions. It is discussed how pyrolysis temperature and duration affect FC activity and stability. But, more important, the results connect the pyrolysis conditions to the required accelerated stress test protocol combination to enable a prediction of the catalyst stability in fuel cells.
The best protocol of accelerated stress tests to mimic the degradation of FeNC in fuel cells depends on the preparation conditions. At mild preparation conditions both, carbon oxidation and active site disintegration overlay, but active site destruction contribute to a major extent. At high pyrolysis conditions carbon oxidation dominates, and an overall much better stability is obtained.
In this paper we would like to present a fully probabilistic symmetric block ciphering algorithm that can work on a distributed computer system. This fact allows to multiply the amount of processed ...information, so the algorithm becomes applicable in BigData.
An important stage in the design of electronic circuits of various classes and purposes is the calculation of the zero-level instability of a developed device under the influence exerted on the ...parameters of its components by external disturbances (variations in temperature, humidity, pressure, radiation, etc.), as well as by technological variations in these parameters in the course of serial manufacturing. A mathematical description of the problem of calculating the zero-level instability of an electronic circuit is constructed for the common case when the coordinates of operating points of all circuit components are known and the task is to find their deviations under variations in the parameters of circuit components caused by external disturbances, as well as under technological variations in these parameters in the course of manufacturing. An advantage of the proposed technique is that it avoids multiple calculations of a nonlinear circuit and its sensitivity to parameter variations, instead dealing with a mathematical description of the linearized circuit, which is used to determine the deviations of variables from their initial stationary values. As a result, the amount of computational operations is dramatically reduced and the computation time is reduced as well, which is especially important for solving optimization problems in electronic circuit design.
There is a dearth of published information on the posterior perforated substance as compared to the anterior perforated substance. We managed to glean facts about the posterior perforated substance ...that can serve as a landmark for surgical operations in the adjacent regions of the midbrain and the vessels passing through it. Moreover, the posterior perforated substance contains the interpeduncular nucleus responsible for the mental state of the individual.
1) To describe the topography of the blood vessels supplying the posterior perforated substance area from the surgical point of view; 2) to investigate the functions of the interpeduncular nucleus.
We assembled and analyzed results from source databases by Elsevier, NCBI MedLine, Scopus, Scholar. Google and Embase. Each article was studied in detail for practically useful information about the posterior perforated substance.
The P1-segment perforating branches of the posterior cerebral artery supply the posterior perforated substance. This area is especially vulnerable in the case of vascular pathologies. The posterior communicating artery can block the surgeon's view and impede maneuverability of the tool in the area of the posterior perforated substance, which may be addressed using the separation technique, which can lead to positive results. In addition, the medial habenula-interpeduncular nucleus in the posterior perforated substance is associated with various addictions and psychiatric conditions.
The posterior perforated substance area is of great interest for surgical interventions. Future studies of the interpeduncular nucleus anticipate the development of drugs to affect different types of dependencies and some mental diseases.
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