Multimode Graded Index Fiber with Random Array of Bragg Gratings and Its Raman Lasing Properties

Light propagation in multimode fibers is known to experience various nonlinear effects, which are being actively studied. One of the interesting effects is the brightness enhancement at the Raman conversion of the multimode beam in graded index (GRIN) fiber due to beam cleanup at Raman amplification and mode selective feedback in the Raman laser cavity based on fiber Bragg gratings (FBGs) with special transverse structure. It is also possible to explore random distributed feedback based on Rayleigh backscattering on natural refractive index fluctuations in GRIN fibers, but it is rather weak, requiring very high power multimode pumping for random lasing. Here, we report on the first realization of femtosecond pulse-inscribed arrays of weak randomly spaced FBGs in GRIN fibers and study Raman lasing at its direct pumping by highly multimode (M2~34) 940-nm laser diodes. The fabricated 1D–3D FBG arrays are used as a complex output mirror, together with the highly reflective input FBG in 1-km fiber. Above threshold pump power (~100 W), random lasing of the Stokes beam at 976 nm is obtained with output power exceeding 28 W at 174 W pumping. The beam quality parameter varies for different arrays, reaching M2~2 at the linewidth narrowing to 0.1–0.2 nm due to the interference effects, with the best characteristics for the 2D array

Random Lasing in Multicore and Multimode Fibers

Random lasers utilize multiple scattering in disordered amplifying medium which provides necessary feedback even in the absence of resonant cavity. 1D random lasing via Rayleigh backscattering in single-mode fibers (SMF) with pump-induced Raman gain enabled generation of stable high-quality narrow-line output beam, which can even outperform traditional Raman fiber lasers (RFLs) with cavity made of fiber Bragg grating (FBG) pairs. Use of multicore or multimode fibers complicates transverse mode structure of random fiber lasers making them closer to traditional bulk-media random lasers, but they offer new opportunities. Here we review our latest results on investigation of random lasing in multicore and multimode fibers. First, random lasing has been explored in a PM twin-core fiber (TCF) with half-open cavity formed by Rayleigh backscattering distributed along TCF and lumped reflector at one fiber end: either a broad-band fiber-loop mirror (FLM) or femtosecond-pulse inscribed in-core FBGs (in one core or in both cores). The inscription of two FBGs in different (but coupled) cores leads to the formation of a Michelson-type interferometer resulting in the multi-wavelength generation with single peak width of < 0.02\ \mathrm{nm}. Second, direct pumping of multimode graded-index (GRIN) fibers by high-power LDs at 915 nm provides Raman lasing at Stokes line near 950 nm selected by multimode fs-inscribed FBGs, whereas 2-order random lasing in half-open cavity with one fs FBG appears possible in a broad wavelength range (978 - 996 nm). At that, the cascaded Raman conversion is accompanied by sufficient improvement of the output beam quality in comparison with that for multimode LDs. As a result, high-efficiency generation of nearly diffraction limited beam in the all-fiber LD-pumped GRIN RFL has been demonstrated

Hematological parameters and micro biocenosis gastrointestinal tract of calves fed with the feed additive “Laktur”

Морозова Лариса Анатольевна. Доктор биологических наук, доцент, заведующая кафедрой технологии хранения и переработки продуктов животноводства, Курганская государственная сельскохозяйственная академия им. Т.С. Мальцева (г. Курган), [email protected] Миколайчик Иван Николаевич. Доктор сельскохозяйственных наук, профессор, декан факультета биотехнологии, Курганская государственная сельскохозяйственная академия им. Т.С. Мальцева (г. Курган), [email protected] Достовалов Евгений Владимирович. Аспирант, Курганская государственная сельскохозяйственная академия им. Т.С. Мальцева (г. Курган). Morozova Larisa Anatolievna. Sc.D., Associate Professor, Head of the Department of Technology of storage and processing of animal products, Kurgan State Agricultural Academy by T.S. Maltsev (Kurgan), [email protected] Mikolajczyk Ivan Nikolaevich. Doctor of Agricultural Sciences, Professor, Dean of the Faculty of Biotechnology, Kurgan State Agricultural Academy by T.S. Maltsev (Kurgan), [email protected] Dostovalov Evgeny Vladimirovich. Graduate student, Kurgan State Agricultural Academy by T.S. Maltsev (Kurgan).В последнее десятилетие концепция пробиотиков претерпела существенные изменения. Возросло внимание исследователей к структурным компонентам и продуктам метаболизма пробиотических микроорганизмов. Данные изменения связаны с расширением представлений о биологической эффективности пробиотиков и обнаружении того факта, что структурные элементы клеток и их метаболиты в ряде случаев оказываются не менее эффективными. Кормовые пробиотические препараты находят широкое применение в практике животноводства, позволяют усовершенствовать существующие системы современного рационального кормления животных. Молочнокислые бактерии, стрептококки и микроорганизмы Bacillus subtilis, входящие в состав ферментативно-пробиотической кормовой добавки «Лактур», мобилизируют синтез полезных биологически активных компонентов в организме, подавляют рост условно-патогенных микроорганизмов, восстанавливают нормальный микробиоценоз кишечника и способствуют профилактике желудочно- кишечных болезней животных. Гематологические исследования позволили выявить, что кормовая добавка «Лактур», благодаря многообразию функций, положительно влияет на эритропоэз телят. Так, количество эритроцитов в крови телят, получавших кормовую добавку «Лактур» в дозе 1,25 кг/т от массы концентрированных кормов, было больше показателя животных контрольной на 8,24 % (Р<0,05), гемоглобина – на 8,23 % (Р < 0,05), остаточного азота – на 17,28 %, содержание кальция и неорганического фосфора – на 17,35 и 8,23 % соответственно. Уровень альбуминовой фракции был больше в данной группе по сравнению с контрольной на 3,07 %. Микробиологические исследования фекалий телят в 120-дневном возрасте показали, что в содержимом кишечника животных, получавших пробиотическую кормовую добавку «Лактур», преобладали лактобактерии. Так, в фекалиях телят, получавших кормовую добавку «Лактур» в дозе 1,25 кг/т, численность лактобактерий составила 8,69 млн КОЕ/г, что на 3,23 млн КОЕ/г, или на 59,16 % (Р<0,05) больше в сравнении с контрольной группой. Также в фекалиях телят опытных групп увеличилось количество бифидобактерий и в среднем составило 4,35 млн КОЕ/г, что на 46,96 % больше по сравнению с контрольной группой. При этом численность эшерихий в содержимом кишечника телят опытных групп снизилась и в среднем составило 4,32 млн КОЕ/г, что на 65,28 % меньше в сравнении с контролем. In the last decade the concept of probiotics has undergone significant changes. It shows increasing attention of researchers in structural components and metabolic products of probiotic microorganisms. These changes are associated with the extension of the concepts of biological effectiveness of probiotics and detecting the fact that the structural elements of the cells and their metabolites in many cases are at least equally effective. Feed probiotic preparations are widely used in animal husbandry practices, allow improving the existing system of modern rational animal feed. Lactic acid bacteria, streptococcus bacteria and Bacillus subtilize, a part of the enzymatically-probiotic feed additive “Laktur” mobilize useful synthesis of biologically active components in the body, inhibit the growth of opportunistic pathogens, restore normal intestinal microbiocenosis and contribute to the prevention of gastrointestinal diseases of animals. Hematologic studies revealed that the feed additive “Laktur” through a variety of functions has a positive effect on erythropoiesis calves. Thus, the number of erythrocytes in the blood of calves treated with the feed additive “Laktur” in a dose of 1.25 kg/ton by weight of the concentrated feed was more than the control animals at 8.24 % (P < 0.05), hemoglobin – 8, 23 % (P < 0.05), residual nitrogen – 17.28 at%, the content of the inorganic calcium and phosphorus – and 17.35 to 8.23 %, respectively. The level of albumin fraction was larger in this group compared with the control to 3.07 %. Microbiological studies of feces in calves 120 days of age showed that the gut contents of animals fed probiotic feed additive “Laktur” lactobacillus dominated. Thus, in calves feces receiving feed supplement “Laktur” in a dose of 1.25 kg/t, the number of lactobacilli was 8,690,000 cfu/g, at 3.23 million CFU/g, or 59.16 % (P < 0.05) than the control group. Also, in experimental groups of calves feces increased amount of bifid bacteria and averaged 4,350,000 CFU/g, which is 46.96% more than the control group. Meanwhile, the number of E. coli in the intestine of calves content decreased and the experimental groups averaged 4.32 million CFU/g, which is 65.28 % lower compared with the control

Extracavity and external cavity second-harmonic generation in a periodically poled silica fiber

We have studied second-harmonic generation (SHG) of a cw single-frequency ytterbium-doped fibre laser, using a periodically poled silica fibre as a nonlinear medium for frequency conversion. All-fibre external cavity SHG has been investigated for the first time. A twofold increase in second-harmonic power in a fibre ring cavity has been demonstrated and possibilities of further optimising the fibre scheme have been analysed

Experimental Investigations of the Electron Cloud Key Parameters

Motivated by a potential electron cloud instability and the possible existence of electron mulitpacting in the LHC vacuum system, that may result in additional gas desorption and unmanageable heat loads on the cryogenic system, an extensive experimental research program is underway at CERN to quantify the key parameters driving these phenomena. Parameters, such as: photoelectron yield, photon reflectivity, secondary electron yield etc. from industrially prepared surfaces have been quantified. In addition to their dependence on photon dose the effect of temperature and presence of external fields has also been studied

Single-Frequency Ring Fiber Laser with Random Distributed Feedback Provided by Artificial Rayleigh Scattering

Femtosecond (fs) laser inscription technology allows for the production of in-fiber disordered structures with an enhanced level of Rayleigh backscattering with relatively few induced losses. These properties enable the application of these structures as reflectors in fiber lasers. In this study, a narrow-linewidth erbium fiber laser with random distributed feedback provided by a fs-induced random structure in a ring cavity configuration was developed. A single-frequency regime was observed over the entire lasing power range. At a maximum output power of 7.8 mW, the linewidth did not exceed 0.75 kHz

Personality Profiles and the "Russian Soul": Literary and Scholarly Views Evaluated

Many domestic and foreign observers have claimed that Russians have a unique constellation of personality traits that mirrors their distinctive historical and cultural experience. To examine the hypothesized uniqueness of Russian personality, members of the Russian Character and Personality Survey collected data from 39 samples in 33 administrative areas of the Russian Federation. Respondents (N = 7,065) identified an ethnically Russian adult or college-aged man or woman whom they knew well and rated the target using the Russian observer-rating version of the Revised NEO Personality Inventory. The mean personality profile of Russians was very similar to the international average based on 50 different countries, debunking the myth of a unique Russian soul. The small variations from world norms did not converge with depictions of Russian national character in fiction and the scholarly literature. New items intended to capture distinctive, emic aspects of Russian personality provided no new information beyond the familiar Big Five dimensions. Religion, ethnicity, and beliefs about the uniqueness of the Russian character and the malleability of personality traits had little effect on personality ratings. Perceptions of the Russian soul do not seem to be based on the personality traits of Russians