The Eect of Mechanical Loading on the Frequency of an Oscillator Circuit

We investigate the effect of mechanical strain on the frequency of an electronic oscillator embedded in an integrated circuit. This analysis is aimed at explaining a 1% inaccuracy in the oscillator frequency under test conditions prescribed by a leading supplier of semi-conductor devices. During the test the package containing the oscillator was clamped to a circuit board by mechanical pressure. By considering the nature of the oscillator we show that tensile strains of the order of 10^-4 could explain the observations via the piezoresistance effect. Both a simple one-dimensional analysis based on the beam equation and an elastic finite element simulation show that strains of this magnitude can be generated during the test

Identification of time-varying nonlinear systems using Chebyshev polynomials

AbstractThis paper is devoted to an identification of time-varying nonlinear systems using Chebyshev polynomials of the first kind. For systems being linear relatively unknown functional parameters, a method of approximate determination of these parameters has been worked out. As the identification problems are ill-posed to solve the obtained redefinite system of linear algebraic equations, a regularization method is used

Development of sers substrates based on nanoparticles obtained by pulsed laser ablation

SERS spectroscopy is an effective method for the determination of organic and biological compounds, which finds its place in many areas of human life: the analysis of works of art and food 24 YOUNG SCIENTISTS SESSION SESSION Y products, the identification of drugs and drugs, the study of biological structures, incl. at the cellular level. The creation of simple and effective SERS substrates is an urgent task in the development of this method. This paper presents the results of a study of SERS substrates based on gold nanoparticles (NPs). Gold NPs were obtained by pulsed laser ablation of an Au metal target in alcohol using a Nd:YAG laser (1064 nm, 7 ns, 150 mJ). The resulting colloidal solution was applied onto glass substrates by the drop method, varying the number of layers. The SERS characteristics were studied using a model dye rhodamine 6G using Renishaw inVia Basis Raman microscope. The samples were excited in the region of surface plasmon resonance of gold by laser radiation of 532 nm. The results of the study showed that with an increase in the number of deposited layers up to 5, the intensity of the Raman scattering of the dye increases linearly. With a further increase in the number of layers, the signal saturates. This data correlates with SEM data. At the beginning, an increase in the packing density of NPs in the plane of the substrate is observed. Accordingly, the number of "hot spots" increases, which contribute to the amplification of the signal. Further, the homogeneity of the NP layer deteriorates, and large bulk agglomerates appear. Thus, we have developed a simple method for obtaining SERS substrates, which made it possible to increase the signal intensity up to three orders of magnitude

Empire after Empire: Military Legacy and the Creation of Nation States

The article was submitted on 17.10.2023.Рассмотрен процесс перехода в новые руки военного имперского наследия, происходивший после 1917 г., особо востребованный из-за того, что этот переход совершался в обстановке обострения политических, этнических и религиозных конфликтов. Важнейшую роль в нем играли носители армейских практик – солдаты, офицеры и генералы различных национальностей. Длительная война сопровождается сепарацией командного состава: не доказавшие своей профессиональной состоятельности военачальники уступают руководящие посты тем, кто лучше проявил себя в руководстве войсками. Турбулентность революционной эпохи, ломая устоявшиеся иерархические схемы, позволила многим честолюбивым и талантливым военачальникам занять высокие посты, что было невозможно в обычной обстановке. Высокая административная нагрузка, лежавшая на генералах и офицерах российской императорской армии, опыт ведения военного хозяйства подготовили их к роли государственных деятелей в новых государствах, возникших на развалинах Российской империи. Военные запасы, сосредоточенные в прифронтовых районах, позволили решить вопросы материального обеспечения национальных вооруженных сил.This article considers the transfer of the military imperial heritage into new hands after 1917, which was especially in demand since this transition took place in an environment of aggravated political, ethnic, and religious conflicts. The most important role in this process was played by the bearers of army practices – soldiers, officers, and generals of various nationalities. A long war was accompanied by a separation of command personnel: military leaders who had not proved their professional worth gave up leadership positions to those who had proved themselves better in leading troops. Breaking the established hierarchical patterns, the turbulence of the revolutionary era allowed many ambitious and talented military leaders to occupy high positions, which was impossible in normal circumstances. The high administrative burden that lay on the generals and officers of the Russian imperial army and the experience of running a military economy prepared them for the role of statesmen in the new states that arose from the ruins of the Russian Empire. Military reserves concentrated in front-line areas made it possible to resolve issues of material support for the national armed forces.Исследование выполнено за счет гранта Российского научного фонда № 23-18-00520

The stabilization of unstable detonation waves for the mixture of nitromethane/methanol

Mass velocity profiles of detonation waves in mixtures of nitromethane with acetone and methanol with added diethylenetriamine sensitizer were measured using a VISAR laser interferometer. It was found that even small, about 1%, concentrations of acetone and methanol, inert diluents, led to instability of the one-dimensional detonation front in nitromethane. The results of the experiment show that the use of the sensitizer is an effective method of flow stabilization and if the concentration of the inert diluent does not exceed 10%, the detonation front becomes stable with the addition of 1% diethylenetriamine. At a higher diluent concentration, the sensitizer does not suppress the instability but decreases the oscillation amplitude by several times. The addition of diethylenetriamine to the mixture has been found to increase the detonation velocity