Граничний вплив неідентичності резистивних елементів високовольтного плеча на частотні характеристики широкосмугового подільника напруги (аналітичне дослідження)

Purpose. Determination in the analytical form of the maximum limiting influence of the non-identity of the resistive elements of the high-voltage arm on the amplitude-frequency characteristic and phase-frequency characteristic of the voltage divider with parallel-series connection of R-, C-elements of the high-voltage arm. Methodology. Based on the previously developed theory of broadband voltage dividers with parallel-series connection of R‑, C-elements, analytical expressions for amplitude-frequency and phase-frequency characteristics of the voltage divider are obtained and investigated taking into account the limit case of non-identical resistive elements of high-voltage arm. Results. The nature of the dependencies of the frequency characteristics of the broadband voltage divider on the value of the tolerance of the resistive elements of the high-voltage arm, the division factor of the voltage divider in a wide range of frequency changes are determined. Simplified approximating expressions for the maximum values of frequency characteristics of the voltage divider are proposed and their error is determined. Originality. For the first time in the analytical form the limiting influence of non-identity of resistive elements of a high-voltage arm of a voltage divider on its frequency characteristics is considered. A mathematical model of this influence is constructed and the limit values of frequency characteristics of the voltage divider are determined. Practical value. It is recommended to introduce into the normative documentation of broadband voltage dividers the corrected value of the division factor, which allows to significantly reduce the deviation of the actual value of the division factor of the voltage divider from the normalized value in a wide range of frequency changes.На основі раніше розвинутої теорії широкосмугових подільників напруги з паралельно-послідовним з’єднанням R-, C-елементів вперше одержані аналітичні вирази для амплітудно-частотної та фазо-частотної характеристик подільника напруги з урахуванням граничного випадку неідентичності резистивних елементів високовольтного плеча. Визначений загальний характер залежностей частотних характеристик від значення допуску резистивних елементів, коефіцієнта ділення подільника напруги в широкому діапазоні зміни частоти. Запропоновані спрощені апроксимуючі вирази для максимальних значень частотних характеристик та визначено їх похибки. Рекомендовано уведення в нормативно-технічну документацію широкосмугових подільників напруги відкоригованого значення коефіцієнта ділення

Граничний вплив неідентичності ємнісних елементів високовольтного плеча на частотні характеристики подільника напруги (аналітичне дослідження)

Purpose. Determination in the analytical form of the maximum limiting influence of the non-identity of the capacitive elements of the high-voltage arm on the amplitude-frequency characteristic and phase-frequency characteristic of the voltage divider with parallel-series connection of R-, C-elements of the high-voltage arm. Methodology. Based on the previously developed theory of broadband voltage dividers with parallel-series connection of R-, C-elements, analytical expressions for amplitude-frequency and phase-frequency characteristics of the voltage divider are obtained and investigated taking into account the limit case of non-identical capacitive elements of high-voltage arm. Results. The nature of the dependencies of the frequency characteristics of the broadband voltage divider on the value of the tolerance of the capacitive elements of the high-voltage arm, the division factor of the voltage divider in a wide range of frequency changes is determined. Simplified approximating expressions for the maximum values of frequency characteristics of the voltage divider are proposed and their error is determined. Originality. For the first time in the analytical form the limiting influence of non-identity of capacitive elements of a high-voltage arm of a voltage divider on its frequency characteristics is considered. A mathematical model of this influence is constructed and the limit values of frequency characteristics of the voltage divider are determined. Practical value. It is recommended to introduce into the normative documentation of broadband voltage dividers the corrected value of the division factor, which allows to significantly reduce the deviation of the actual value of the division factor of the voltage divider from the normalized value in a wide range of frequency changes.На основі раніше розвинутої теорії широкосмугових подільників напруги з паралельно-послідовним з’єднанням R-, C-елементів вперше одержані аналітичні вирази для амплітудно-частотної та фазо-частотної характеристик подільника напруги з урахуванням граничного випадку неідентичності ємнісних елементів високовольтного плеча. Визначений загальний характер залежностей частотних характеристик від значення допуску ємнісних елементів, коефіцієнта ділення подільника напруги в широкому діапазоні зміни частоти. Запропоновані спрощені апроксимуючі вирази для максимальних значень частотних характеристик та визначена їх похибка. Рекомендовано уведення в нормативну документацію широкосмугових подільників напруги відкоригованого значення коефіцієнта ділення

Draft genome sequences of gammaproteobacterial methanotrophs isolated from marine ecosystems

The genome sequences of Methylobacter marinus A45, Methylobacter sp. strain BBA5.1, and Methylomarinum vadi IT-4 were obtained. These aerobic methanotrophs are typical members of coastal and hydrothermal vent marine ecosystems

RANGING THE KHABAROVSK KRAY TERRITORIES BY THE LEVELS OF DYSENTERY EPIDEMIC MANIFESTATIONS

Aim: to reveal the Khabarovsk region territories that are under high risk of spread of dysentery in the period of large-scale flood fallout liquidation. Materials and methods. There was the analysis conducted of dysentery incidence during the period of 2003-2012 including distribution of annual and long-term annual average indicators per 100 000 inhabitants throughout administrative entities of Khabarovsk territory. We used methods that reveal tendencies and evaluated dynamic rates of dysentery epidemic process in time. Results and discussion. Khabarovsk region shows uneven levels of manifestations of epidemic process of dysentery not only during evaluation of annual incidence but also among certain administrative territories. During ten years preceding the flood in the Amur River region, long-term annual average level of incidence equaled to 42.7 ± 1.740/0000 The epidemic process was most intense in the Nanayi region, in other six administrative regions long-term annual average levels of incidence were exceeding similar averaged levels in Khabarovsk region. An intense epidemiologic situation on dysentery in several territories of the region was associated with registration of foci of clustered incidence caused by dysentery Sonne of alimentary and water-borne origin including atypical variants of Shigella Sonne. Conclusion. A year before the flood the elevation of dysentery incidence was registered in most of the territories of Khabarovsk Kray, and there was the evidence of outlined tendency of activation of epidemic process. This served as a basis for required adequate emergency measures for prophylaxis of dysentery

Soil methane sink capacity response to a long-term wildfire chronosequence in Northern Sweden

Boreal forests occupy nearly one fifth of the terrestrial land surface and are recognised as globally important regulators of carbon (C) cycling and greenhouse gas emissions. Carbon sequestration processes in these forests include assimilation of CO2 into biomass and subsequently into soil organic matter, and soil microbial oxidation of methane (CH4). In this study we explored how ecosystem retrogression, which drives vegetation change, regulates the important process of soil CH4 oxidation in boreal forests. We measured soil CH4 oxidation processes on a group of 30 forested islands in northern Sweden differing greatly in fire history, and collectively representing a retrogressive chronosequence, spanning 5000 years. Across these islands the build-up of soil organic matter was observed to increase with time since fire disturbance, with a significant correlation between greater humus depth and increased net soil CH4 oxidation rates. We suggest that this increase in net CH4 oxidation rates, in the absence of disturbance, results as deeper humus stores accumulate and provide niches for methanotrophs to thrive. By using this gradient we have discovered important regulatory controls on the stability of soil CH4 oxidation processes that could not have not been explored through shorter-term experiments. Our findings indicate that in the absence of human interventions such as fire suppression, and with increased wildfire frequency, the globally important boreal CH4 sink could be diminished

Differential energy measurement between He- and Li-like uranium intra-shell transitions

We present the first clear identification and highly accurate measurement of the intra-shell transition 1s2p\, ^3P_2 \to 1s2s\, ^3S_1 of He-like uranium performed via X-ray spectroscopy. The present experiment has been conducted at the gas-jet target of the ESR storage ring in GSI (Darmstadt, Germany) where a Bragg spectrometer, with a bent germanium crystal, and a Ge(i) detector were mounted. Using the ESR deceleration capabilities, we performed a differential measurement between the 1s2p\, ^3P_2 \to 1s2s\, ^3S_1 He-like U transition energy, at 4510 eV, and the 1s^22p\ ^2P_{3/2} \to 1s^22s\, ^2S_{1/2} Li-like U transition energy, at 4460 eV. By a proper choice of the ion velocities, the X-ray energies from the He- and Li-like ions could be measured, in the laboratory frame, at the same photon energy. This allowed for a drastic reduction of the experimental systematic uncertainties, principally due to the Doppler effect, and for a comparison with the theory without the uncertainties arising from one-photon QED predictions and nuclear size corrections

Observation of the 2p3/2 -> 2s1/2 intra-shell transition in He-like uranium

We present the first observation of the 1s2p 3P2 ? 1s2s 3S1 transition in He-like uranium. The experiment was performed at the internal gas-jet target of the ESR storage ring at GSI exploiting a Bragg crystal spectrometer and a germanium solid state detector. Using the 1s2 2p 2P3/2 ? 1s2 2s 2S1/2 transition in Li-like uranium as reference and the deceleration capabilities of the ESR storage rings, we obtained the first evaluation of the He-like heavy ion intra-shell transition energy

Approaching the Gamow Window with Stored Ions : Direct Measurement of Xe 124 (p,γ) in the ESR Storage Ring

© 2019 American Physical Society. All rights reserved.We report the first measurement of low-energy proton-capture cross sections of Xe124 in a heavy-ion storage ring. Xe12454+ ions of five different beam energies between 5.5 and 8 AMeV were stored to collide with a windowless hydrogen target. The Cs125 reaction products were directly detected. The interaction energies are located on the high energy tail of the Gamow window for hot, explosive scenarios such as supernovae and x-ray binaries. The results serve as an important test of predicted astrophysical reaction rates in this mass range. Good agreement in the prediction of the astrophysically important proton width at low energy is found, with only a 30% difference between measurement and theory. Larger deviations are found above the neutron emission threshold, where also neutron and γ widths significantly impact the cross sections. The newly established experimental method is a very powerful tool to investigate nuclear reactions on rare ion beams at low center-of-mass energies.Peer reviewedFinal Published versio