Helically corrugated waveguide microwave pulse compression experiments

A high microwave pulse compressor based on a large diameter 5-fold helical waveguide structure was studied. The eigenwave dispersion was calculated using numerical and analytical techniques and compared with experimental measurements. The results of 5-fold helically corrugated waveguide microwave pulse compression experiments will be presented

Periodic GW level microwave pulses in X-band from a combination of a relativistic backward wave oscillator and a helical waveguide compressor

Backward Wave Oscillators (BWO's) utilizing moderately relativistic (550kV), high-current (10 kA) electron beams are capable of producing hundreds of MWs of pulsed radiation in the centimeter wavelength range. Such relativistic BWOs (RBWOs) allow for broadband, smooth, frequency-tuning via adjustment of the accelerating potential; making them an attractive source for use in frequency-swept pulse compression. This paper presents results of a 2.86m long 5-fold helically corrugated, dispersive pulse compressor where a maximum power compression ratio of 25 was achieved by compressing an input microwave pulse of 80 ns duration swept from 9.65 GHz to 9.05 GHz into a 1.6ns Gaussian-envelope pulse. For an average input power of 5.8 kW generated by a conventional traveling wave tube amplifier, a peak pulse output power of 145 kW was measured corresponding to an energy efficiency of 66%. An X-band relativistic BWO, designed to drive a 0.97m long 5-fold compressor, was built and tested using the accelerating potential generated by a SINUS-6 highcurrent accelerator. The experimental RBWO operated close to the predicted power of 700MW with its oscillation frequency varied from 10 to 9.6GHz via the falling edge of the voltage pulse. It was demonstrated that the 15ns duration frequency-swept part of the RBWO pulse was effectively compressed resulting in a 4.5-fold peak power increase with a maximum power of 3.2 GW generated. The potential for a 5-fold helical waveguide to compress longer duration pulses generated by a RBWO is discussed

Group names for herbal medicines: the need for introduction and rationale for establishing

The article considers the importance of International Nonproprietary Names (INNs) and group names in the development of common information standards for the industry in the light of creation of the EurAsEC market and shared information space. The necessity to define the rules for assigning group names to herbal drugs results from the requirement introduced to Federal Law No. 61-FZ «On circulation of medicines», making it obligatory to specify group names on drug labels in the absence of INNs in the State Register of pharmaceutical products. The article covers the development of the methodological approach to establishing group names for the mentioned group of medicinal products

Selective Dimerization of Ethene to 2-Butene on Zn²⁺-Modified ZSM-5 Zeolite

Selective dimerization of ethene to 2-butene on Zn2+-containing ZSM-5 zeolite (Zn2+/ZSM-5) at 296-523 K has been discovered. The intermediate but-3-en-1-ylzinc species is identified with 13C CP/MAS NMR and Fourier transform infrared spectroscopy. The density functional theory study of two alternative dimerization pathways reveals that the intermediate is formed with the involvement of the saturated bridged dimeric Zn-(CH2)4-O species. It is also shown that ethene conversion to 2-butene increases with the increase in the quantity of Brønsted acid sites in Zn2+/ZSM-5 zeolite; however, the selectivity of the reaction decreases. The results obtained are of potential interest for developing industrially relevant Zn-containing zeolite catalysts for the selective conversion of ethene to 2-butene. Green Open Access added to TU Delft Institutional Repository ‘You share, we take care!’ – Taverne project https://www.openaccess.nl/en/you-share-we-take-care Otherwise as indicated in the copyright section: the publisher is the copyright holder of this work and the author uses the Dutch legislation to make this work public.ChemE/Inorganic Systems Engineerin

Pulse compression using a five-fold helically corrugated waveguide

Microwave pulse compression results from a five-fold helically corrugated waveguide are presented. In these experiments an X-band microwave pulse of duration 80 ns and a 6% frequency sweep was compressed from 5.8 kW to 128kW into a 1.6 ns pulse with a compression factor of 22 in the peak power

Группировочные наименования лекарственных растительных средств: необходимость введения, рациональность формирования

The article considers the importance of International Nonproprietary Names (INNs) and group names in the development of common information standards for the industry in the light of creation of the EurAsEC market and shared information space. The necessity to define the rules for assigning group names to herbal drugs results from the requirement introduced to Federal Law No. 61-FZ «On circulation of medicines», making it obligatory to specify group names on drug labels in the absence of INNs in the State Register of pharmaceutical products. The article covers the development of the methodological approach to establishing group names for the mentioned group of medicinal products.Рассмотрен вопрос о значении международного непатентованного наименования и группировочного наименования в создании отраслевых информационных стандартов в связи с созданием рынка ЕврАзЭС и формированием единого информационного пространства. Введение в Федеральный закон № 61-ФЗ «Об обращении лекарственных средств» требования указания группировочного наименования при отсутствии международного непатентованного наименования в государственном реестре лекарственных средств, в маркировке лекарственных средств обусловило необходимость определения правил формирования группировочного наименования для лекарственных средств растительного происхождения. Статья посвящена вопросу разработки методического подхода к установлению группировочных наименований для данной группы лекарственных средств

5-fold helically corrugated waveguide dispersion measurements

The results of 3-fold helically corrugated waveguide microwave pulse compression experiments are presented. A pulse of 80 ns duration having a power of 5.6 kW is compressed into a 140 kW peak power pulse of 1.5 ns duration. To enhance the power capabilities of the microwave pulse compressor a larger diameter 5-fold helical waveguide structure was studied; the eigenwave dispersion is discussed using numerical, analytical, and experimental techniques

Generation of 3 GW microwave pulses in X-band from a combination of a relativistic backward-wave oscillator and a helical-waveguide compressor

The phenomenon of passive compression of frequency-modulated (FM) pulses in a dispersive media (DM) was used to increase the peak microwave power up to the multigigawatt level A helically corrugated waveguide was used as the DM, while a relativistic X-band backward-wave oscillator (RBWO) with a descending-during-the-pulse accelerating voltage served as a source of FM pulses Compression of pulses down to a halfwidth of 2 2 ns accompanied by a 4 5-fold power increase up to a value of about 3 2 GW has been demonstrated