Modeling and design of working elements of micromechanical gyroscopes (angular rate sensors)

Запропоновано математичну модель мікромеханічного вібраційного гіроскопа камертонного типу. Для підвищення ефективності проектування МЕМС гіроскопа створено алгоритм визначення параметрів робочого органа мікромеханічного гіроскопа. Сформульовано задачі системного рівня проектування і запропоновано шляхи їх розв’язання. Досліджено взаємозв’язок конструктивних параметрів і встановлено, що їх оптимальні значення залежать від необхідних технічних характеристик гіроскопа.The mathematical model of micromechanical vibratory tuning-fork gyroscope is proposed. For increasing the efficiency of the MEMS gyroscope design, the algorithm for calculation of working elements of the micromechanical gyroscope has been created. The system-level problems of designing are defined and their solutions are proposed. The interdependence of the constructional elements have been researched, and it was established that their optimal values depend on the required technical characteristics of the gyroscope

An Evaluation of the Excitation Class Parameter for the Central Stars of Planetary Nebulae

The three main methods currently in use for estimating the excitation class of planetary nebulae (PNe) central stars are compared and evaluated using 586 newly discovered and previously known PNe in the Large Magellanic Cloud (LMC). In order to achieve this we ran a series of evaluation tests using line ratios derived from de-reddened, flux calibrated spectra. Pronounced differences between the methods are exposed. Diagrams were created by comparing excitation classes with H-beta line fluxes. The best methods are then compared to published temperatures using the Zanstra method and assessed for their ability to reflect central star effective temperatures and evolution. As a result we call for a clarification of the term `excitation class' according to the different input parameters used. The first method, which we refer to as Exneb relies purely on the ratios of certain key emission lines. The second method, which we refer to as Ex* includes modeling to create a continuous variable and, for optically thick PNe in the Magellanic Clouds, is designed to relate more closely to intrinsic stellar parameters. The third method, we refer to as Ex [OIII]/H-beta since the [OIII]/H-beta ratio is used in isolation to other temperature diagnostics. Each of these methods is shown to have serious drawbacks when used as an indicator for central star temperature. Finally, we suggest a new method (Exrho) for estimating excitation class incorporating both the [OIII]/H-beta and the HeII4686 /H-beta ratios. Although any attempt to provide accurate central star temperatures using the excitation class derived from nebula lines will always be limited, we show that this new method provides a substantial improvement over previous methods with better agreement to temperatures derived through the Zanstra method.Comment: 14 pages, 18 figure. This peer reviewed paper has been accepted for publication in PAS

A study of the interplay between ionized gas and star clusters in the central region of NGC 5253 with 2D spectroscopy

ABRIDGED: A detailed 2D study of the central region of NGC5253 has been performed to characterize the stellar and ionized gas structure as well as the extinction distribution, physical properties and kinematics of the ionized gas in the central ~210pc x 130pc. We utilized optical integral field spectroscopy (IFS) data obtained with FLAMES. A detailed extinction map for the ionized gas in NGC5253 shows that the largest extinction is associated with the prominent Giant HII region. There is an offset of ~0.5" between the peak of the optical continuum and the extinction peak in agreement with findings in the infrared. We found that stars suffer less extinction than gas by a factor of 0.33. The [SII]l6717/[SII]l6731 map shows an electron density (N_e) gradient declining from the peak of emission in Ha (790cm^-3) outwards, while the argon line ratio traces areas with $N_e~4200 - 6200cm^(-3). The area polluted with extra nitrogen, as deduced from the excess [NII]/Ha, extends up to distances of 3.3" (~60pc) from the maximum pollution, which is offset by ~1.5" from the peak of continuum emission. Wolf-Rayet features are distributed in an irregular pattern over a larger area (~100pc x 100pc) and associated with young stellar clusters. We measured He^+ abundances over most of the field of view and values of He^++/H^+<~0.0005 in localized areas which do not coincide, in general, with the areas presenting W-R emission or extra nitrogen. The line profiles are complex. Up to three emission components were needed to reproduce them. One of them, associated with the giant HII region, presents supersonic widths and [NII] and [SII] emission lines shifted up to 40km/s with respect to Ha. Similarly, one of the narrow components presents offsets in the [NII] line of <~20km/s. This is the first time that maps with such velocity offsets for a starburst galaxy have been presented.Comment: accepted in Astronomy & Astrophysics. 21 pages, 22 figure

Calculation and design of spring suspensions of microelectromechanical (MEMS) gyroscopes

У даній роботі розроблено методику проектування підвісу робочого органа МЕМС гіроскопа, а саме конструктивних розмірів пружин у залежності від необхідних параметрів гіроскопа, таких як товщина, ширина пружин та їх довжина, тобто від габаритних розмірів гіроскопа. Розроблена методика дозволяє створити підсистему автоматизованого проектування системи пружного підвісу МЕМС гіроскопа.In this work, design technique of the working organ suspension of MEMS gyroscope, that is springs dimensions depending on the required gyroscope performance, such as the thickness and the width of the springs and their length, hence the overall dimensions of the gyroscope, is developed. The developed technique allows to create computer-aided design subsystem of the spring elements of the MEMS gyroscope

Mathematical model for research of technical characteristics of integrated angular velocity microsensor

Запропоновано математичну модель для дослідження технічних характеристик інтегрального мікросенсора кутової швидкості, проведено моделювання впливу параметрів його конструкції та матеріалів її виготовлення на технічні характеристики мікросенсора, такі, як частоти робочих і вимірювальних коливань чутливого елемента мікросенсора і його чутливість. На основі змодельованих залежностей резонансних частот від конструктивних параметрів мікросенсора побудовано скінченноелементну модель його конструкції в САПР ANSYS і проведено моделювання її поведінки.In the paper, the mathematical model for research of technical characteristics of the integrated angular velocity microsensor has been proposed. The model of the microsensor is shown as the simplified model “sensing element - damper”. By using the proposed mathematical model, the research of influence of construction parameters and fabrication materials of the integrated angular velocity microsensor on its technical characteristics, such as drive and sense oscillations of the sensing element of the microsensor and its sensitivity, is performed. The relationship between the normalized sensitivity of the microsensor Sdn and the ratio of (ωx/ωy) for different quality Qy values is simulated and graphically presented. Simulation of the dependency of drive and sense frequencies of the oscillating movement of the sensitive element on the constructive parameters of the spring element, such as its length, width and thickness, for such materials as SiC, Si, SiO2, Si3N4, Ge, SiGe is performed and graphically depicted. It has been researched that the resonant frequency decreases as the length of the spring element increases; resonant frequency increases as the width of the spring element increases; resonant frequency increases as the thickness of the spring element increases; driving mode frequency is more sensitive to the length and width of the spring element and less sensitive to its thickness; the sensing mode frequency is more sensitive to the length and thickness of the spring element and less sensitive to its width. On the base of the performed simulation of the dependency of the resonance frequencies on the constructive parameters of the integrated angular velocity microsensor, the finite element model of its construction in ANSYS is created and the simulation of its behavior is performed. In modal analysis of ANSYS model of the integrated angular velocity sensor, its mode shapes and frequencies are obtained. The obtained results can be further used for creation of VHDL-AMS, SUGAR models for MEMS computer-aided design subsystem

THE MASSES OF THE IONIZED GAS OF PLANETARY NEBULAE ENVELOPES IN LARGE MAGELLANIC CLOUD

The masses of ionized gas in the shells of planetary nebulae which belong in the Large Magellanic Cloud are calculated by three different ways. The value of mass is calculated for the cases: 1) spherical, 2) elliptical forms of envelopes and 3) commonly known method based on the line ratio F(Hβ) of the shell to its emissivity of  ε(Hβ). It is shown that the values of masses Mi  of nebulae envelopes differ up to 50%. The values of  Mi  calculated by the other methods which differ more from previous ones. We consider the dependence of Mi  on the radius and the electron density in the envelopes of nebulae. The masses of ionized gas in the shells of planetary nebulae which belong in the Large Magellanic Cloud are calculated by three different ways. The value of mass is calculated for the cases: 1) spherical, 2) elliptical forms of envelopes and 3) commonly known method based on the line ratio F(Hβ) of the shell to its emissivity of  ε(Hβ). It is shown that the values of masses Mi  of nebulae envelopes differ up to 50%. The values of  Mi  calculated by the other methods which differ more from previous ones. We consider the dependence of Mi  on the radius and the electron density in the envelopes of nebulae.

Verilog – ams model of comb-drive sensing element of integrated capacitive microaccelerometer for behavioral level of computer aid design

The article presents Verilog – AMS model of the comb-drive sensing element of the integrated capacitive microaccelerometer. The suggested model allows to simulate the reaction of the sensing element effected by the applied force of acceleration, changes of its comb-drive capacities, output voltages and currents for determining its constructive parameters and for analysis of the mechanical module of the integrated device at the behavioral level of computer-aided design

Development of the basic acoustic elements models on the base of the VHDL – AMS language for computer-aided design at the schemotechnical level

In this paper the basic acoustic elements models are developed on the base of the VHDL-AMS language. Constructed models are based on the thin plates theory and are intended to be used in computer-aided design at the schematic level of basic acoustic MEMS elements. The results of the models for basic acoustic elements of piezoelectric and electrostatic types investigation are also presented

Математическая модель пьезорезистивного микросенсора давления для компонентного уровня проектирования

Розроблено математичну модель п'єзорезистивного МЕМС давача тиску. Змодельовано реакцію мікродавача, спричинену дією прикладеного тиску, а саме механічні напруження в його діафрагмі, її максимальний прогин, зміну опорів вимірювальних п'єзорезисторів, вихідну напругу мостової схеми Вітстона. Досліджено вплив геометричної форми і конструктивних розмірів діафрагми на її максимальний прогин і чутливість мікродавача від прикладеного тиску. Побудована модель мікродавача тиску може бути використана для аналізу його вихідних параметрів на компонентному рівні проектування.A mathematical model of the piezoresistive microelectromechanical systems (MEMS) pressure sensor has been proposed. The proposed model makes possible to simulate the reaction of the microsensor depending on the applied external pressure, induced mechanical stresses in the microsensor diaphragm, changes of the resistances of the sensing piezoresistors, output voltage of the Wheatstone bridge for its construction parameters. The influence of the geometric shapes and constructive parameters of the diaphragm on its maximum deflection and the microsensor sensitivity depending on the applied pressure is investigated. The proposed model can be used to conduct the analysis of the pressure microsensor at the component design level.Разработана математическая модель пьезорезистивного МЕМС сенсора давления. Смоделирована реакция микросенсора, вызванная действием приложенного давления, а именно механические напряжения в его диафрагме, ее максимальный прогиб, изменения сопротивлений пьезорезисторов, исходное напряжение мостовой схемы Витстона. Исследовано влияние геометрической формы и конструктивных размеров диафрагмы на ее максимальный прогиб и чувствительность микросенсора от приложенного давления. Разработанная модель микросенсора давления может быть использована для анализа его исходных параметров на компонентном уровне проектирования

Using the achievements of J.M. Keynes to strengthen modern Ukraine

Тези аналізують роль і значення окремих положень макроекономічної теорії Дж.М. Кейнса для розвитку України в умовах військової агресії російської федерації Theses analyze the role and significance of separate provisions of the macroeconomic theory J.M. Keynes for the development of Ukraine in the context of the military aggression of the Russian Federatio