Hybrid method and vibrational stability for nonlinear singularly perturbed systems under parametric excitations

The well-known classic feedback and feedforward techniques are the main tools for investigations of the control problems. Unlike these strategies, the vibrational control technique, introduced by S.M. Meerkov [1], has proven to be a viable alternative to conventional feedback and feedforward strategies in stabilization problems when the outputs, states and disturbances are difficult to access. Mathematical modelling of such systems is closely connected with nonlinear singularly perturbed systems under parametric excitations. In this paper a new asymptotical method based on the periodic solution theory, averaging method and boundary functions method, is presented. Due to it, a vibrational control problem can be investigated. The given example shows the "parasitic" parameters loss in such systems to be extremly dangerous

Spectral properties of coupled wave equations

Essential features of two-section DFB semiconductor lasers can be described by a boundary value problem for the so-called coupled wave equations, a linear hyperbolic system of first order partial differential equations with piecewise constant coefficients. In this paper we investigate spectral properties of an operator H defined by this boundary value problem. We prove that H generates a C0-group of bounded operators in a suitable Hilbert space 풰, that all but finitely many eigenvalues of H are simple and have negative real parts and that there exists a basis in 풰 consisting of root functions of H, where all but finitely many of these root functions are eigenfunctions

The impact of antibodies to human glycoprotein CD4 and gamma-interferon on the t-cell immunity and the cytokine levels in patients co-infected with HIV/HCV during the antiretroviral therapy

Objective: This work was to estimate the influence of antibodies to human glycoprotein CD4 and IFN-γ on the T-cell immunity and the cytokine levels in patients with HIV and HIV/HCV during the standard antiretroviral therapy. Materials and methods: Randomized clinical trial in parallel groups. 4 groups were included: patients with HIV receiving ART (20) or ART and antibodies (AB) (19) for 3 months; patients with HIV/HCV, receiving ART (17) or ART and AB (20) for 3 months. The obtained data included: CD3+, CD4+, CD8+ cell count; IFN-γ, IL-2 and IL-4 concentrations; HIV viral load. Results: The significant increase of CD4+ cell number and IFN-γ were found in patients receiving ART and antibodies. These changes were followed with more significant decline in the viral load. Conclusion: The antibodies to human glycoprotein CD4 and IFN-γ added to standard ART increased the CD4+ cell count and IFN-γ levels in patients with HIV/HCV, followed by the trend to increase the number of patients with viral load >50 ml-1. Thus, the administration of ART supplemented with antibodies to human glycoprotein CD4 and IFN-γ resulted in the increase of antiviral immunity. Further clinical trials in HIV or HIV patients with co-infections could be recommended

Development and validation of a quantitative HPLC/MS/MS method for the determination of piperacillin in blood plasma

Reduced mortality in patients with sepsis taking piperacillin is possible when they receive a long-term infusion, which improves the effect of antimicrobials. However, such piperacillin therapy requires therapeutic drug monitoring, the use of the latest analytical equipment and developed methods for the quantitative determination of piperacilli

ПРОГРАММИРОВАНИЕ ДВУХБИТНОГО PIN-ДИОДА В СРЕДЕ SYNOPSYS SENTAURUS TCAD

The article is devoted to the modeling of a two-bit pin-diode. The possibility of programming opening time of the device based on the pin-diode is shown. The design consisting of a pin diode and two floating gates on the surface of i-region is considered. The addition of electrodes to the surface of the i-region makes it possible to regulate the concentration of electrons and holes within the larger limits in compare with the single-gate structure creating enriched and depleted are-as in the structure. Programming is carried out by applying the appropriate voltage to the control electrodes of the floating gates. It is shown that the charge generated on the floating gate changes characteristics of the i-region of the pin diode.The key elements of complex simulation of the two-gate pin diode are simulation of charge accumulation mechanism on the floating gate, simulation of pin-diode opening time and calibration of numerical model. Simulation is performed in Synopsys Sentaurus TCAD. Physical models describing traps and their parameters, particle tunneling, transport phenomena in dielectrics and amorphous films are used in simulation. As a result of modeling, the opening time dependences on size, floating gate location and floating gate charge magnitude are obtained.It is shown that the pin-diode 2-gate structures allow to change the opening time in a wider range than the single-gate ones. To program a large range of pin-diode opening times, it is 2 gate structure that is advisable to use. The obtained results indicate that it is possible to implement a two-bit programming pin-diode and expand its functionality.Статья посвящена моделированию двухбитного pin-диода. Показана возможность программирования времени открытия устройства на основе pin-диода. Рассмотрена конструкция, состоящая из pin-диода и двух плавающих затворов на поверхности i-области. Добавление электродов на поверхность i-области дает возможность регулировать концентрацию электронов и дырок в больших пределах в сравнении с однозатворной структурой, создавая обогащенные и обедненные области в структуре. Программирование осуществляется подачей соответствующего напряжения на управляющие электроды плавающих затворов. Показано, что создаваемый на плавающем затворе заряд изменяет характеристики i-области pin-диода.Важными элементами комплексного моделирования двухзатворного pin-диода являются моделирование механизма накопления заряда на плавающих затворах, моделирование времени открытия pin-диода, калибровка численной модели. Моделирование выполнено в среде Synopsys Sentaurus TCAD. При моделировании были использованы физические модели, описывающие ловушки и их параметры, туннелирование частиц, явления переноса в диэлектриках и аморфных пленках. В результате моделирования получены зависимости времени открытия от размеров, расположения плавающих затворов и значения заряда на плавающих затворах.Показано, что двухзатворные структуры pin-диода позволяют изменять время открытия в более широких пределах, чем однозатворные. Для программирования большого диапазона времен открытия pin-диода целесообразно использовать именно двухзатворные структуры. Полученные результаты свидетельствуют о расширении функциональных возможностей двухзатворной структуры

International economic relations of world philatelic business: the history of foundation, development and modern status

The research work is about history of foundation and modern existence of the system of the world economics relations in the sphere of philatelic business which provides the development and spread of one of the popular hobby, collecting the postage stamps in the World

GEO-ECONOMICS: METHOD OF COGNITION TO THE METHOD STEPS

The article discusses the emergence of the concept of geo-economics and relationship with geopolitics and transformation of the world economy and international economic relations. Particular attention is paid to the role of geo-economics at the present stage of confrontation economies of East and West. The article deals with the causes and consequences of economic competition of the three centers of the world: Western Europe, North America and the Far East. Explained the real reasons for the imposition of economic sanctions against Russia

Humanitarian and economic aspects of digitalization in road safety systems

In the article we examine relevant problems regarding human rights on roads with arising digitalized processes. The problems cover three aspects. First, are the rights of drivers, passengers, and impaired individuals who use digitalized management systems while on the roads. Second, is the protection of the rights of those who are dismissed from driving the public transport with digitalized management systems. Third, is the potential danger to the society from economic outcomes of further digitalization. In the end, the article gives a comprehensive argument about the importance of securing human rights on the roads as it was brought up to our attention by the United Nations.Following the afore mentioned aspects of the problem, the article derives hypothetical solutions regarding human rights of road users with arising digitalized process. First of all, it remains essential to reinforce drivers’ rules on the roads. Next, safety of pedestrians, people who are travelling on foot, needs to be ensured since they are worse off in case of an emergency on the roads. Finally, it is a special focus on ensuring the rights of persons with disabilities. The latter applies not only to the drivers and pedestrians, but also to passengers with disabilities who use the means of urban ground transportation