Study of Self-Diffusion of n-Decane in NaX Zeolite by the Pulsed Magnetic-Field Gradient NMR Method

Translational mobility of n-decane molecules in a porous space of NaX zeolite was studied within the wide ranges of diffusion times and temperatures. The dependence of the effective self-diffusion coefficient on diffusion time was established. Confined mobility of diffusant molecules inside the crystallite was observed both for complete and partial filling of NaX pores with a liquid, when the adsorption barrier was absent at the interface between intra- and intercrystallite regions. It was suggested that obstacles are present at the surface of NaX crystallites complicating the transfer of liquid molecules from crystallite channels to intercrystallite space. True value of self-diffusion coefficient of n-decane in the itracrystallite space of NaX was determined and its dependence on the concentration of liquid molecules in zeolite channels was considered. A special attention was paid to the study of molecular exchange between intra- and intercrystallite-confined liquids

ЭФФЕКТИВНОСТЬ ДВУХКАНАЛЬНОГО ОПТИЧЕСКОГО ПРИЕМНИКА СИГНАЛОВ С ДИФФЕРЕНЦИАЛЬНОЙ ФАЗОВОЙ МОДУЛЯЦИЕЙ

A comparative analysis of optical receivers to handle differential phase-shift keying (DPSK) was presented in this paper. The two-channel optical receiver providing sensitivity gain was proposed. Numerical investigation of its performance was carried out.Проведен сравнительный анализ известных оптических приемных модулей для обработки сигналов с дифференциальной фазовой модуляцией (DPSK) при отсутствии оптических предусилителей. Предложен двухканальный оптический приемник, позволяющий получить выигрыш по чувствительности по сравнению с ранее известными. Проведен анализ его эффективности

Ionospheric Effects of a Solar Eclipse of March 20, 2015 on Oblique Sounding Paths in the Eurasian Longitudinal Sector

© 2016, Springer Science+Business Media New York.The results of measuring HF signals on oblique chirp sounding paths in the Eurasian region during a solar eclipse of March 20, 2015 and the neighboring days are presented. The solar eclipse took place against the background of a strong magnetic storm. It was established that during the solar eclipse on oblique sounding paths of different length and orientation the decrease in the maximum observable frequency for the F mode (MOF-F) and the lowest observable frequency for the F mode (LOF-F) was 8–14% and 22–33%, respectively. During the eclipse, the signal amplitude increased by 3–5 dB. On the Lovozero—Nizhny Novgorod path in the maximum phase of the solar eclipse, the electron density decrease in the ionospheric E and F2 layers at the midpoint of the path reached 37% and 22%, respectively. According to the MOF and LOF variation measurements for various modes, the group delay time of radio signals, and the results of spectral analysis, it was found that in the eclipse there were wave disturbances with a period of 25 to 50 min. However, quasi-periodic variations of MOF-F and LOF-F having a a period of 50 to 80 min but which started before the eclipse were detected on some paths. Probably, in these cases, the variations were a result of the superposition of disturbances from two sources, namely, the magnetic storm and the solar eclipse

Impact of a Strong Magnetic Storm and Two X-Ray Flares on the Ionospheric HF Channel in the Summer Solstice of 2015 According to Oblique Sounding in the Eurasian Region

© 2017, Springer Science+Business Media, LLC. We present the results of observations of the impact a strong magnetic storm and two X-ray flares in the summer solstice of 2015 on the HF signal characteristics during oblique sounding of the ionosphere in the Eurasian region. It was found that the negative phase of the magnetic storm led to a strong degradation of the ionospheric channel, up to a long blackout on the paths adjacent to the subauroral latitudes. On the midlatitude paths, a decrease in the maximum observable frequency of the F layer reached 50% with respect to the average values for an undisturbed ionosphere. The propagation velocity of the negative phase of a disturbance from the subauroral to the midlatitude ionosphere is determined (it is equal to about 100 m/s). It is shown that during a magnetic storm the least observable frequency and the average signal-to-noise ratio for the propagation mode via the sporadic E s layer correlate well with the auroral AE index. Anomalous signals were detected in the main phase of the magnetic storm on the Cyprus—Rostov-on-Don path when a chirp ionosonde–radio direction finder was operated in the over-the-horizon HF radar mode. On the basis of modeling and comparison with experimental data, it is shown that the anomalous signals are due to scattering of radio waves by small-scale irregularities located in the subauroral ionospheric F region

ВЛИЯНИЕ НЕЛИНЕЙНЫХ ИСКАЖЕНИЙ НА ВСТРЕЧНЫЙ КАНАЛ ПРИЕМА В ПАССИВНЫХ ОПТИЧЕСКИХ СИСТЕМАХ, ВЫЗВАННЫХ ВЫНУЖДЕННЫМ РАССЕЯНИЕМ МАНДЕЛЬШТАМА-БРИЛЛЮЭНА

An analysis of nonlinear distortion in passive optical networks (PON), due to stimulated Mandel'shtam - Brillouin scattering is performed. It is shown that starting with a pump power of the signal / noise ratio at the input of the receiver opposite direction decreases sharply, which leads to increased likelihood of errors.Произведен анализ нелинейных искажений в пассивных оптических сетях (PON), вызванных вынужденным рассеянием Мандельштама-Бриллюэна. Показано, что начиная с некоторой мощности накачки отношение сигнал/шум на входе приемника встречного направления резко уменьшается, что ведет к повышению вероятности ошибки

Impact of a Strong Magnetic Storm and Two X-Ray Flares on the Ionospheric HF Channel in the Summer Solstice of 2015 According to Oblique Sounding in the Eurasian Region

© 2017 Springer Science+Business Media, LLC We present the results of observations of the impact a strong magnetic storm and two X-ray flares in the summer solstice of 2015 on the HF signal characteristics during oblique sounding of the ionosphere in the Eurasian region. It was found that the negative phase of the magnetic storm led to a strong degradation of the ionospheric channel, up to a long blackout on the paths adjacent to the subauroral latitudes. On the midlatitude paths, a decrease in the maximum observable frequency of the F layer reached 50% with respect to the average values for an undisturbed ionosphere. The propagation velocity of the negative phase of a disturbance from the subauroral to the midlatitude ionosphere is determined (it is equal to about 100 m/s). It is shown that during a magnetic storm the least observable frequency and the average signal-to-noise ratio for the propagation mode via the sporadic E s layer correlate well with the auroral AE index. Anomalous signals were detected in the main phase of the magnetic storm on the Cyprus—Rostov-on-Don path when a chirp ionosonde–radio direction finder was operated in the over-the-horizon HF radar mode. On the basis of modeling and comparison with experimental data, it is shown that the anomalous signals are due to scattering of radio waves by small-scale irregularities located in the subauroral ionospheric F region

Impact of heliogeophysical disturbances on ionospheric HF channels

© 2017 COSPAR. The article presents the results of the observation of a strong magnetic storm and two X-ray flares during the summer solstice in 2015, and their impact on the HF signals characteristics in ionospheric oblique sounding. It was found that the negative phase of the magnetic storm led to a strong degradation of the ionospheric channel, ultimately causing a long blackout on paths adjacent to subauroral latitudes. On mid-latitude paths, the decrease in 1FMOF reached ∼50% relative to the average values for the quiet ionosphere. It is shown that the propagation conditions via the sporadic Es layer during the magnetic storm on a subauroral path are substantially better than those for F-mode propagation via the upper ionosphere. The delay of the sharp decrease in 1FMOF during the main phase of the magnetic storm allowed us to determine the propagation velocity of the negative phase disturbances (∼100. m/s) from subauroral to mid-latitude ionosphere along two paths: Lovozero - Yoshkar-Ola and Cyprus - Nizhny Novgorod. It is shown that both the LOF and the signal/noise ratio averaged over the frequency band corresponding to the propagation mode via the sporadic Es layer correlate well with the auroral AE index. Using an over-the-horizon chirp radar with a bistatic configuration on the Cyprus - Rostov-on-Don path, we located small-scale scattering irregularities responsible for abnormal signals in the region of the equatorial boundary of the auroral oval

РЕОЛОГИЧЕСКИЕ СВОЙСТВА КРОВИ У ПАЦИЕНТОВ С ТОЛСТОКИШЕЧНОЙ НЕПРОХОДИМОСТЬЮ ОПУХОЛЕВОГО ГЕНЕЗА В РАННЕМ ПОСЛЕОПЕРАЦИОННОМ ПЕРИОДЕ

Introduction. Microcirculation plays an important role in early postoperative period in colorectal cancer patients. At the same time the question connected with studying of rheological properties of blood as one of microcirculation indicators in literature it studied insufficiently.Materials and methods. We studied rheological properties of blood in 30 patients operated for bowel obstruction caused by right colon cancer. 17 (56,7 %) patients were male, 13 (43,3 %) – female. Average age was 57 ± 3 years. Time from the moment of manifestation of the first clinical signs before admission to a hospital and the beginnings of carrying out medical and diagnostic actions was 12 ± 0,5 h. The stage of a disease was T3N0–1M0. The group of comparison consisted of 20 healthy volunteers of the same age. Changes of a rheology of blood were measured by means of the accounting of viscosity of blood, change of an index of deformation and aggregation of erythrocytes. Studying of viscosity of blood was carried out by means of the rotational viscometer at shift speeds: 200; 100; 150; 50 and 20 MPas. Measures were conducted at the time of receipt, on the first, third, fifth, seventh and tenth postoperative day.Results. In patients with bowel impassability at the time of receipt the increase in indicators of viscosity of blood is noted at all speeds of the shift, analyzed indicators increase by the third postoperative day, decrease on the seventh and are partially restored for the tenth postoperative days. Complications developed in 16,6 % of cases, in all cases – pneumonia. By comparison of the obtained laboratory data to a clinical picture it is established that complications developed on 3–5th postoperative days.Введение. Немаловажное значение в течение ближайшего послеоперационного периода у больных раком толстой кишки отводится изменениям микроциркуляции. Вместе с тем вопрос, связанный с изучением реологических свойств крови как одного из показателей микроциркуляции, в литературе освещен недостаточно.Материалы и методы. Нами проведено изучение реологических свойств крови у 30 пациентов, оперированных по поводу толстокишечной непроходимости опухолевого генеза. У всех пациентов непроходимость была вызвана опухолью правой половины толстой кишки. Из общего числа больных мужчин было 17 (56,7 %), женщин – 13 (43,3 %). Средний возраст оперированных составил 57 ± 3 года. Время от момента проявления первых клинических признаков до поступления в стационар и начала проведения лечебно-диагностических мероприятий составило 12 ± 0,5 ч. Стадия заболевания – T3N0–1M0. Группу сравнения составили 20 относительно здоровых добровольцев того же возраста и пола. Изменения реологии крови выявлялись с помощью учета вязкости крови, изменения индекса деформации и агрегации эритроцитов. Изучение вязкости крови проводилось при помощи ротационного вискозиметра при скоростях сдвига: 200; 100; 150; 50 и 20 с-1. Исследования проводили в момент поступления, на 1, 3, 5, 7 и 10-е послеоперационные сутки.Результаты. У пациентов с толстокишечной непроходимостью в момент поступления отмечается увеличение показателей вязкости крови при всех скоростях сдвига, анализируемые показатели увеличиваются на 3-и послеоперационные сутки, снижаются на 7-е и частично восстанавливаются на 10-е послеоперационные сутки. Осложнения развились в 16,6 % наблюдений, во всех наблюдениях отмечено развитие пневмонии. При сопоставлении полученных лабораторных данных с клинической картиной установлено, что осложнения развились на 3–5-е послеоперационные сутки

Direct photodetection and coherent reception with different modulation techniques in open optical communication systems with stationary space objects

Рассмотрена эффективность прямого фотодетектирования и методы когерентного приема оптических сигналов инфракрасного диапазона длин волн с различными видами модуляции в открытых системах связи со стационарными космическими объектами. The efficiency of direct photodetection and methods of coherent reception of optical signals in infrared wavelength range with different modulation techniques in open communication systems with stationary space objects were considered

АТАКИ НА ПАССИВНЫЕ ОПТИЧЕСКИЕ СЕТИ СО СТОРОНЫ АБОНЕНТСКОГО ОКОНЧАНИЯ

The analysis of construction principles of passive optical networks was carried out. Options for attacks on PON-network and attacks from the subscriber were discussed. The possibility of such attacks was evaluated. Method of protection from attacks by use of scheme of WDM-PON was proposed.Проведен анализ принципов построения пассивных оптических сетей. Рассмотрены варианты атак на PON-сеть, а также атаки со стороны абонентского окончания. Проведена оценка возможности таких атак. Предлагается метод защиты от атак путем применения схемы WDM-PO