Microprocessor electronics in space instrument making

Volumes of information processed on board the spacecraft (SC) is constantly growing, the algorithms of the onboard systems - complicated. Therefore, a need for new solutions in the field of system architecture SC. Operating conditions are very complex spacecraft: overload when starting, temperature, radiation, and other negative factors of outer space , as well as the inability to repair a running companion , require onboard equipment reliability and survivability. Architecture used today onboard control systems and data do not satisfy in full all these requirements. Need a new concept of architecture - board information and control systems of spacecraft, which provides high functionality and reliability of such systems.Volumes of information processed on board the spacecraft (SC) is constantly growing, the algorithms of the onboard systems - complicated. Therefore, a need for new solutions in the field of system architecture SC. Operating conditions are very complex spacecraft: overload when starting, temperature, radiation, and other negative factors of outer space , as well as the inability to repair a running companion , require onboard equipment reliability and survivability. Architecture used today onboard control systems and data do not satisfy in full all these requirements. Need a new concept of architecture - board information and control systems of spacecraft, which provides high functionality and reliability of such systems

Fluorescent properties of the kindling fluorescent protein (KFP) at acidic pH values

Kindling fluorescent protein (KFP) is the photoswitchable protein which can be used in high-resolution microscopy and as a quencher in FRET-sensors. Fluorescent properties of KFP depend on pH value. In this paper we investigate the influence of pH on the spectral properties and kindling/quenching ability of KFP in the acidic pH region.Shift to the acidic region leads to the increase of fluorescence intensity of KFP over time. The excitation spectrum has a new peak near 455nm, giving two peaks - 530 and 590nm – in emission spectrum. We can assume that this maximum corresponds to the appearance of protonated form of the KFP chromophore.Analysis of fluorescence decay curves of KFP in H2O and D2O showed the presence of the kinetic isotope effect, which can be caused by the proton transfer from solvent molecules to the KFP chromophore, confirming the hypothesis that in the acidic pH region protonated form of KFP chromophore appears.At acidic pH irradiation of KFP with green light doesn’t lead to fluorescence increase, while blue light doesn’t quench the fluorescence. It means that KFP is also in the bright form, and there is no conformational states of protein which can be quenched by blue light

Single crystal growth and properties of MgB2 and Mg(B1-xCx)2

Single crystals of MgB2 and Mg(B1-xCx)2 have been grown using cubic anvil technique. Tc values vary in a wide range (39-9 K) with carbon content varying from 0 up to 16%. Using SiC as the precursor leads to C and not to Si substituted crystals. Micro-hardness measurements performed on MgB2 single crystals give average value of 1100 kg/mm2.Comment: 6 pages, 3 figures. submitted to Physica C (M2S-Rio proceedings

Microprocessor electronics in space instrument making

Volumes of information processed on board the spacecraft (SC) is constantly growing, the algorithms of the onboard systems - complicated. Therefore, a need for new solutions in the field of system architecture SC. Operating conditions are very complex spacecraft: overload when starting, temperature, radiation, and other negative factors of outer space , as well as the inability to repair a running companion , require onboard equipment reliability and survivability. Architecture used today onboard control systems and data do not satisfy in full all these requirements. Need a new concept of architecture - board information and control systems of spacecraft, which provides high functionality and reliability of such systems.Volumes of information processed on board the spacecraft (SC) is constantly growing, the algorithms of the onboard systems - complicated. Therefore, a need for new solutions in the field of system architecture SC. Operating conditions are very complex spacecraft: overload when starting, temperature, radiation, and other negative factors of outer space , as well as the inability to repair a running companion , require onboard equipment reliability and survivability. Architecture used today onboard control systems and data do not satisfy in full all these requirements. Need a new concept of architecture - board information and control systems of spacecraft, which provides high functionality and reliability of such systems

U-3M plasma startup scenario sustained by gas puffing as a different plasma confinement scenario: first results

In order to reduce flux of neutrals into the plasma confinement volume, discharge start-up scenario maintained by impulse gas puffing (GP) has been proposed. Absence of constant working gas feeding in this scenario opens a possibility to reduce working gas pressure in the U-3M vacuum vessel. It was shown that the time of entire vessel filling after sharp gas puffing pulse is about 10…20 ms. In discharges with 5…6 kV on the RF generators and proposed start-up scenario, a delay between GP pulse and plasma creation was shorter than the chamber filling time. The same level of the electron density has been achieved in the discharge under consideration and conventional 5…6 kV discharge maintained by the constant gas feeding only. The Hα emission waveform in the considered discharges is similar to its waveforms in the conventional devices where the sizes of vacuum chamber and plasma are close each other.Для того, чтобы уменьшить поток нейтралов в объем удержания плазмы, был предложен сценарий разряда У-3М, поддерживаемого импульсным напуском газа. Отсутствие постоянной подачи газа в этом сценарии позволяет уменьшить давление рабочего газа в вакуумной камере У-3М. Было показано, что время заполнения вакуумной камеры У-3М после резкого импульса напуска газа составляет около 10...20 мс. В разрядах с 5...6 кВ на ВЧ-генераторах в режиме предложенного сценария напуска газа задержка между импульсом напуска и созданием плазмы была короче времени заполнения камеры. Тот же уровень плотности электронов был достигнут в рассматриваемом разряде и обычном 5...6 кВ разряде, поддерживаемом только постоянной подачей газа. Форма временной зависимости эмиссии линии Hα в рассматриваемых разрядах похожа на форму этой зависимости в обычных установках, в которых размеры плазмы и камеры близки друг к другу.Для того, щоб зменшити потік нейтралів в об’єм утримання плазми, був запропонований сценарій розряду У-3М, що підтримується імпульсним напуском газу. Відсутність постійної подачі газу в цьому сценарії дозволяє зменшити тиск робочого газу у вакуумній камері У-3М. Було показано, що час заповнення вакуумної камери У-3М після різкого імпульсу напуску газу становить близько 10...20 мс. У розрядах з 5...6 кВ на ВЧ-генераторах у режимі запропонованого сценарію напуску газу затримка між імпульсом напуску і створенням плазми була коротшою ніж час заповнення камери. Той же рівень густини електронів був досягнутий в розглянутому розряді і звичайному 5...6 кВ розряді, що підтримується тільки постійною подачею газу. Форма часової залежності емісії лінії Hα в розглянутих розрядах схожа на форму цієї залежності в звичайних установках, в яких розміри плазми і камери близькі один до одного

Scroll waves in isotropic excitable media : linear instabilities, bifurcations and restabilized states

Scroll waves are three-dimensional analogs of spiral waves. The linear stability spectrum of untwisted and twisted scroll waves is computed for a two-variable reaction-diffusion model of an excitable medium. Different bands of modes are seen to be unstable in different regions of parameter space. The corresponding bifurcations and bifurcated states are characterized by performing direct numerical simulations. In addition, computations of the adjoint linear stability operator eigenmodes are also performed and serve to obtain a number of matrix elements characterizing the long-wavelength deformations of scroll waves.Comment: 30 pages 16 figures, submitted to Phys. Rev.

Creation of low density starting plasma with small frame antenna at Uragan-3M device

Deficient shot-to-shot stability of Uragan-3M discharges makes difficult to reproduce experimental results over the period of experimental session. An efficient way of reducing difference between shots is creation of initial low density plasma before the main discharge to start up. A RF pre-ionization in the same frequency range as that of the main discharge is used in the Uragan-3M torsatron. The pre-ionization provides stable discharges during the whole experimental campaign. The main parameters of the pre-ionization plasma are measured and discussed.Нестабильность разрядов Урагана-3М затрудняет воспроизведение экспериментальных результатов в течение одной экспериментальной кампании. Эффективным способом устранения различия между параметрами плазмы в разных импульсах является предионизация ВЧ-разрядной низкоплотной плазмой, которая создается малой рамочной антенной. Предионизация обеспечивает стабильность разрядов в течение всей экспериментальной кампании. Были измерены и оценены основные параметры предионизационной плазмы.Нестабільність розрядів Урагана-3М утрудняє відтворення експериментальних результатів на протязі однієї експериментальної кампанії. Ефективним способом усунення різниці між параметрами плазми в різних імпульсах є передіонізація ВЧ-розрядною низькощільною плазмою, яка створюється малою рамковою антеною. Передіонизація забезпечує стабільність розрядів на протязі всієї експериментальної кампанії. Були виміряні й оцінені основні параметри передіонізаційної плазми