343 research outputs found

    Statistical properties of a free-electron laser revealed by the Hanbury Brown and Twiss interferometry

    Full text link
    We present a comprehensive experimental analysis of statistical properties of the self-amplified spontaneous emission (SASE) free-electron laser (FEL) FLASH at DESY in Hamburg by means of Hanbury Brown and Twiss (HBT) interferometry. The experiments were performed at the FEL wavelengths of 5.5 nm, 13.4 nm, and 20.8 nm. We determined the 2-nd order intensity correlation function for all wavelengths and different operation conditions of FLASH. In all experiments a high degree of spatial coherence (above 50%) was obtained. Our analysis performed in spatial and spectral domains provided us with the independent measurements of an average pulse duration of the FEL that were below 60 fs. To explain complicated behaviour of the 2-nd order intensity correlation function we developed advanced theoretical model that includes the presence of multiple beams and external positional jitter of the FEL pulses. By this analysis we determined that in most experiments several beams were present in radiating field and in one of the experiments external positional jitter was about 25% of the beam size. We envision that methods developed in our study will be used widely for analysis and diagnostics of the FEL radiation.Comment: 29 pages, 14 figures, 3 table

    Effects of Maternal Hyperhomocysteinemia on the Early Physical Development and Neurobehavioral Maturation of Rat Offspring

    Get PDF
    © 2016, Springer Science+Business Media New York.During pregnancy, several complications have been associated with hyperhomocysteinemia (HHcy) and elevated homocysteine (Hcy) levels have been shown to play a role in the etiology of preeclampsia, placental abruption, intrauterine growth retardation, and neural tube defects and associated with the neurological consequences. In the present work, we investigated the effects of chronic maternal HHcy on the development and neurobehavioral maturation of the offspring. We analyzed classical parameters of development such as body weight, eyelid opening, ear unfolding, incisor eruption, and the appearance of hair, and subjected the pups to various tests that reflected the neurobehavioral maturation extending from 4th to 20th postnatal days (righting reflex, negative geotaxis, cliff avoidance, head shake, acoustic startle reflex, free-fall righting, cliff avoidance caused by visual stimulus, olfactory discrimination). We have shown that newborn animals were characterized by lower body weight and higher mortality. Besides, the delay in neurobehavioral maturation of the pups from the Hcy group was observed. The obtained results indicate that early developmental impairments of brain maturation induced by prenatal HHcy may underlie long-term deficits in the learning and memory behaviors

    THE DETECTION OF THE NECESSARY CONDITIONS OF EFFECTIVE FUNCTIONING OF THE BALL CLEANING SYSTEM OF THE TUBES OF STEAM TURBINE CONDENSERS. Part 1

    Get PDF
    A problem of an increase of the power of turbine by improving heat transfer in condensers of steam turbines is considered in the article as a topical one. The analysis of contamination of the internal surfaces of cooling tubes and of the influence of pollution on the process of heat transfer in turbine condensers has been fulfilled. The existing method of cleaning of condenser tubes with the use of porous elastic balls of sponge rubber that is implemented on a number of large thermal power plants and state region power plants of the Republic of Belarus is examined. In the operation of the ball cleaning system a significant drawback has been revealed, viz. a low efficiency of this method due to the failure to comply with preparation the system of circulating water for operation. Also, a certain imperfection of ball cleaning system technology has been determined. One of the prerequisites for the effective functioning of the ball cleaning system is a certain degree of purity of the pipe system of the condenser, characterized by the coefficient of purity. To determine the effectiveness of ball cleaning system a series of experiments on the launching of porous rubber balls in the pipe system of the main and the embedded bunches of the T-250/300-240 UTMZ turbine has been produced. Immediately before the experiments hydraulic cleaning of the tubes of the condenser by a high-pressure installation were carried out. During the experiments, records of the number of downloaded porous rubber balls, of the number of rubber balls captured in a loading chamber, and of the number of rubber balls that remained in a calibration device were kept. A large proportion of default of the balls caused by the presence of residues of the carbonate sediments, that obstruct the movement of porous rubber balls in the tubes of the condenser, was determined. The presence of carbonate deposits in the tubes of the condenser indicates a lack of effectiveness of antiscale treatment of circulating water and of hydraulic method of cleaning tubes of the condenser

    Investigation of radiation effects in water solutions during exposure with laser or LEDs light

    Get PDF
    Abstract only.The installation for gamma-, X-ray and neutron registration in water solutions (600 ml LiOH, or NaOH, or Na2CO3) during exposure with red light (λ=645+/-20 nm) of laser or light-emission devises (LEDs) was created. The laser light power was 5 mW and the LEDs - from 600 mW up to 10 W. Neutrons were measured with help of tow 3He counters, placed in paraphine barrel. Small neutron emission (up to 100 neutrons) has been registered in the form of series of short (ms) bursts during some minutes. Tritium production has also been detected in water solution probes. The gamma-ray and X-ray radiation measured by NaI scintillation detector & Geiger counters was not detected. Received results are discussed

    Microwave-Assisted synthesis and evaluation of antibacterial activity of novel 6-fluoroaryl-[1,2,4]triazolo[1,5-A]pyrimidines

    Full text link
    A series of 6-fluoroaryl substituted [1,2,4]triazolo[1,5-A]pyrimidines have been synthesized by using the microwave-Assisted Suzuki cross-coupling reaction from readily available 6-bromo-[1,2,4]triazolo[1,5-A]pyrimidine. The antimicrobial activity of new compounds has been evaluated in vitro against Mycobacterium tuberculosis H37Rv and gram-negative (Neisseria gonorrhoeae ATCC 49226) bacteria. © ARKAT-USA, Inc

    Оценка влияния температуры на скорость ползучести высокотемпературных элементов паровых турбин и паропроводов

    Get PDF
    The paper considers a high temperature influence on strength characteristics of steam pipelines and steam turbine parts of high and medium pressure. The charts showing a decisive temperature importance in diffuse creep have been presented in the paper. The paper contains a calculation of steel self-diffusion coefficient. Dependence Dsd = f(t) for more accurate assessment of  resource characteristics of the applied steel has been proposed in the paper.Рассмотрено влияние высокой температуры на прочностные характеристики паропроводов и частей турбин высокого и среднего давления. Представлены диаграммы, подтверждающие, что температура имеет определяющее значение при диффузной ползучести. Рассчитан коэффициент самодиффузии стали. Предложено использовать зависимость Dsd = f(t) для более точной оценки ресурсных характеристик применяемых сталей

    Hierarchical morphogenetic analysis of Kursk chernozem

    Get PDF
    Each of four hierarchical levels in the morphogenetic research is characterized in terms of technical and information facilities. A detailed hierarchical study was performed for the first time for chernozems and may be qualified for a basic one. Its results comprise confirmation of occurrence and details in manifestations of pedogenetic processes well-known in chernozems, as well as additional information on the pedofauna contribution to chernozem formation, variability and dynamics of carbonate pedofeatures, stability of the mineral soil ingredients

    Efficiency of the using singulyar at treatment of the bronchial asthma beside children

    Get PDF
    Using singulyar for reinforcement base treatment beside children allows to reach checking on clinical symptoms of the bronchial asthma and vastly perfect the factors to functions of the external breathing at more short periods

    Cytokine Level Changes in Schizophrenia Patients with and without Metabolic Syndrome Treated with Atypical Antipsychotics

    Get PDF
    The present study aims at comparing the change in cytokine levels in schizophrenia patients treated with atypical antipsychotics, with or without metabolic syndrome (MetS). The study included 101 patients with schizophrenia, 38 with and 63 without MetS, who received risperidone, quetiapine, olanzapine or aripiprazole for six weeks. We analyzed the concentration of 21 cytokines in the serum patients. The treatment with atypical antipsychotics changed some proinflammatory cytokine levels. It led to increased IFN-alpha 2 (p = 0.010), IL-1 alpha (p = 0.024) and IL-7 (p = 0.017) levels in patients with MetS, whereas the same treatment led to decreased levels of IFN-gamma (p = 0.011), IL-1 beta (p = 0.035), IL-12p40 (p = 0.011), IL-17A (p = 0.031), IL-6 (p = 0.043) and TNF-alpha (p = 0.012) in individuals without MetS. Our results demonstrated the effects of atypical antipsychotics on the immune-inflammatory parameters, depending on the metabolic disturbances in schizophrenia patients

    Synthesis of novel [1,2,4]triazolo[1,5-b][1,2,4,5]tetrazines and investigation of their fungistatic activity

    Full text link
    A series of novel [1,2,4]triazolo[1,5-b][1,2,4,5]tetrazines has been synthesized through oxidation reaction of the corresponding 3,6-disubstituted 1,2,4,5-tetrazines bearing amidine fragments. It is shown that the heterocyclic systems obtained can be modified easily at C(3) position in the reactions with aliphatic alcohols and amines. Also, the reactivity of [1,2,4]triazolo[1,5-b][1,2,4,5]tetrazines towards CH-active compounds has been studied. The obtained triazolo[1,5-b]annulated 1,2,4,5-tetrazines proved to be active in micromolar concentrations in vitro against filamentous anthropophilic and zooanthropophilic dermatophyte fungi (Trichophyton, Microsporum and Epidermofiton), which cause skin and its appendages (hair, nails) diseases. © 2022 Korotina et al.; licensee Beilstein-Institut.Ministry of Education and Science of the Russian Federation, Minobrnauka: 075-15-2020-777; Ural Branch, Russian Academy of Sciences, UB RASThis work was supported by the Ministry of Education and Science of the Russian Federation (Agreement No. 075-15-2020-777).Analytical studies were carried out using equipment of the Center for Joint Use “Spectroscopy and Analysis of Organic Compounds”, located in Postovsky Institute of Organic Synthesis of the Ural Branch of the Russian Academy of Sciences. This work was supported by the Ministry of Education and Science of the Russian Federation (Agreement No. 075-15-2020-777)
    corecore