Establishment of the spectra of kinetic turbulence

An analysis of kinetic equations describing the establishment of Langmuir turbulence spectra is presented. Secondary turbulence occurs where stationary distribution consists of many peaks. The position of peaks is established and their amplitudes complete undamped oscillations. It is pointed out that establishing spectra can occur only during adiabatic inclusion of pumping. It is significant here that the adiabiatic condition is more rigid than the ordinary by several hundred times

Detection of Trace Amounts of Toxic Metals in Environmental Samples by Laser-excited Atomic Fluorescence Spectrometry

Results for the direct determination of trace amounts of Pb and Cd in Antarctic and Greenland ancient ice and recent snow by laser-excited atomic fluorescence spectrometry (LEAFS) are presented. The whole procedure starting from field sampling, mechanical decontamination of the samples in an ultra-clean laboratory and final analysis of the decontaminated samples is described. The measured concentrations varied in the ranges 0.1–3 pg ml^(–1) for Cd and 0.3–30 pg ml^(–1) for Pb. The results for direct analysis by LEAFS agree favourable with those obtained by isotope dilution mass spectrometry and electrothermal atomic absorption spectrometry, which require time-consuming pre-treatment and pre-concentration stages

Monte Carlo study of linear chain submonolayer structures.Application to Li/W(112)

The lattice gas model for adsorption of alkaline elements on W(112) surface is studied by Monte Carlo simulations. The model includes dipole--dipole interaction as well as long-range indirect interaction. The numerical results show that truncation of the indirect interaction even at 200$\AA$ may change a phase diagram, i.e., new phases containing domain walls might occur. It is demonstrated that a defected phase can exist at high temperatures even if it is not stable at T=0. The phase diagram for Li/W(112) is constructed and long periodic chain structures (9*1), (6*1), (4*1), (3*1), and (2*1) are found to be stable at low temperatures. Role of thermal fluctuation is discussed by comparison of Monte Carlo results with mean field approximation results.Comment: 7 pages, 7 figures, REVTe

Cost of human capital estimation and management in medical organization

© Medwell Journals, 2016.The purpose of this research is the analysis and improvement of technology of human capital cost management for maintaining efficient personnel policy in a modern organization. The study offers researchers method of assessment and management of investments in human capital. This method involves structure of cost behavior during formation and development of human capital, change history of investment risks on each stage of business career, modeling of volume of investments on various degrees of their riskiness, mathematical analysis and forecasting profitability of investments in human capital, development of recommendations on human capital cost management. Furthermore, it determines investment appeal of human capital development. The real method is assayed on the materials of a project on human capital development in "KORL" JSC. To maintain human capital cost management we offer systematic monitoring of its current value and change on the basis of the offered optimizing models, following the investment approach for personnel decision making, personalization in accounting the investments in human capital and its profitability

A model of linear chain submonolayer structures. Application to Li/W(112) and Li/Mo(112)

We propose a lattice gas model to account for linear chain structures adsorbed on (112) faces of W and Mo. The model includes a dipole-dipole interaction as well as a long-ranged indirect interaction. We have explicitly demonstrated that the periodic ground states depend on a competition between dipole-dipole and indirect interaction. The effect of temperature is studied within the molecular-field approximation. The numerical results show that for dipole-dipole interaction only, all long periodic linear chain phases are suppressed to low temperatures. However, when the long-range indirect interaction becomes important, the long-periodic linear chain phases start to fill up the phase diagram and develop a high thermal stability. Model parameters are chosen to reconstruct a sequence of long-periodic phases as observed experimentally for Li/Mo(112) and Li/W(112).Comment: RevTeX 9 pages + 5 Postscript figures (included), uses newdoc.sty (included), to be published in Surface Scienc

About the acceleration rate of relativistic beams by a surface wave in a dielectric laser accelerator

An analysis of the dependence of the acceleration rate of charged particles by a surface wave arising when a laser pulse/(plane wave) is incident on the interface between two dielectric media on the phase velocity of the excited wave is carried out. It is shown that at resonance acceleration this dependence has a maximum, for ultra-relativistic particles the acceleration rate tends to zero. The dependences of the acceleration rate on the phase velocity of the excited wave for various refractive indices (dielectric permittivities) of optically transparent medias are investigated analytically and numerically.Проведено аналіз залежності темпу прискорення заряджених частинок поверхневої хвилею, що виникає при падінні лазерного імпульсу/(плоскої хвилі) на межу розділу двох середовищ, від фазової швидкості хвилі, що збуджується. Показано, що при резонансному прискоренні ця залежність має максимум, для ультрарелятивістських частинок темп прискорення прагне до нуля. Аналітично та чисельно досліджено залежності темпу прискорення від фазової швидкості хвилі, що збуджується, для різних показників заломлення (діелектричної проникності) оптично прозорих матеріалів.Проведен анализ зависимости темпа ускорения заряженных частиц поверхностной волной, возникающей при падении лазерного импульса/(плоской волны) на границу раздела двух сред, от фазовой скорости возбуждаемой волны. Показано, что при резонансном ускорении эта зависимость имеет максимум, для ультрарелятивистских частиц темп ускорения стремится к нулю. Аналитически и численно исследованы зависимости темпа ускорения от фазовой скорости возбуждаемой волны для различных показателей преломления (диэлектрических проницаемостей) оптически прозрачных материалов

УСТРАНЕНИЕ МАТРИЧНЫХ НЕСПЕКТРАЛЬНЫХ ПОМЕХ ПРИ ЭЛЕМЕНТНОМ АНАЛИЗЕ БИОЛОГИЧЕСКИХ ЖИДКОСТЕЙ НА КВАДРУПОЛЬНОМ МАСС-СПЕКТРОМЕТРЕ С ИНДУКТИВНО СВЯЗАННОЙ ПЛАЗМОЙ

The comparison of two most frequently used sample preparation techniques of biological fluids before mass-spectrometric determination of Mn, Co, Cu, Zn, As, Se, Cd and Pb – simple (direct) dilution and acid mineralization – was carried out using quadrupole mass-spectrometer. The significant underestimation of the results in comparison with diluted samples for the elements with relatively high ionization potentials was found while analyzing digested biofluids. The key role of acid effect was proven to be the reason of such discrepancy. Moreover, the contributions of saline and organic matrix non-spectral interferences in both diluted and mineralized samples – to the underestimation of the obtained results were evaluated. It was shown that the selection of the appropriate internal standard based on matching of the standard’s and analyte’s ionization potentials not the masses can eliminate the described interferences without matrix-matched calibration. Furthermore, the working mass-spectrometer conditions that allow to use any single internal standard (irrespective of it’s mass and/or ionization potential) were found. Based on the experimental data the approach of element determination in biological fluids with the use of quadrupole ICP-MS was suggested. It provides the possibility of simultaneous determination of various elements without changing the work mass-spectrometer conditions. The satisfactory agreement between the found and certified concentration values for all the elements analyzed in the diluted and mineralized samples of whole blood and urine reference materials proved the applicability of the approach.Keywords: biological fluids, elemental analysis, inductively coupled mass-spectrometry, matrix non-spectral interferences, internal standards(Russian)DOI: http://dx.doi.org/10.15826/analitika.2014.18.2.003 K.B. Osipov1, I. F. Seregina1, M. A. Bol`shov1,2 1Lomonosov Moscow State University, Moscow, Russian Federation2Institute for Spectroscopy RAS, Troitsk, Moscow, Russian FederationНа примере определения Mn, Co, Cu, Zn, As, Se, Cd и Pb в цельной крови и моче с использованием квадрупольного масс-спектрометра с индуктивно связанной плазмой Agilent 7500c произведено сравнение двух наиболее часто применяемых способов пробоподготовки биологических жидкостей: прямого разбавления и кислотного разложения. Обнаружено значительное занижение результатов анализа в минерализованных пробах (по сравнению с результатами анализа в разбавленных образцах) для элементов с относительно высоким первым потенциалом ионизации. Показано, что основной причиной такого расхождения является различие проб и градуировочных растворов по матричному составу: высокая кислотность проб после разложения. Дополнительно оценены вклады солевого и органического состава матрицы в занижение получаемых результатов как в разложенных, так и разбавленных пробах. Установлено, что для устранения подобных помех при использовании масс-спектрометра данной комплектации без подбора матрицы градуировочных растворов ключевым является выбор элемента внутреннего стандарта, который осуществляется, исходя из близости его первого потенциала ионизации к соответствующему потенциалу ионизации определяемого элемента. Найден режим работы прибора, который позволяет использовать один любой внутренний стандарт независимо от его природы – атомной массы и/или потенциала ионизации. На основании проведенных исследований предложена схема анализа указанных образцов с использованием квадрупольного масс-спектрометра с индуктивно связанной плазмой, обеспечивающая одновременное определение различных элементов без оптимизации рабочих параметров для каждого аналита. Удовлетворительное совпадение между найденными и аттестованными значениями концентраций всех элементов, определяемых в разбавленных и разложенных образцах сравнения цельной крови и мочи, подтверждает применимость подхода.Ключевые слова: биологические жидкости, элементный анализ, масс-спектрометрия с индуктивно связанной плазмой, матричные неспектральные помехи, внутренний стандарт.DOI: http://dx.doi.org/10.15826/analitika.2014.18.2.003

Theory and numerical modeling of electrical self-potential signatures of unsaturated flow in melting snow

We have developed a new theory and numerical model of electrical self-potential (SP) signals associated with unsaturated flow in melting snow. The model is applicable to continuous natural-melt and transient-flow phenomena such as melt-water pulses, and is tested using laboratory column experiments. SP signals fundamentally depend on the temporal evolution of snow porosity and melt-water flux, electrical conductivity (EC) and pH. We infer a reversal of the sign of the zeta potential (a fundamental electrical property of grain surfaces in porous media), consistent with well-known elution sequences of ions that cause progressive increases and decreases in melt-water pH and EC respectively. Injection of fully-melted snow samples, containing the entire natural range of ions, into melting snow columns caused additional temporary reversals of the sign of the zeta potential. Widely-used empirical relationships between effective saturation, melt-water fraction, EC and pH, as well as snow porosity, grain size and permeability are found to be robust for modelling purposes. Thus, non-intrusive SP measurements can serve as proxies for snow melt-water fluxes and the temporal evolution of fundamental snow textural, hydraulic or water-quality parameters. Adaptation of automated multi-sensor SP acquisition technology from other environmental applications thus promises to bridge the widely acknowledged gap in spatial scale between satellite remote sensing and point measurements of snow properties. SP measurements and modelling may therefore contribute to solving a wide range of problems related to the assessment of water resource availability, avalanche or flood risk, or amplification of climatic forcing of ice-shelf, ice-sheet or glacier dynamics

Acceleration of electron bunches using periodic dielectric structures with and without coating

The numerical studies of high acceleration gradients obtaining for the dielectric laser accelerators (DLA) based on-chip structures with one-sided laser excitation at a wavelength of 800 nm are presented. The electron flight heights of 200 and 400 nm over a structure are presented. The influence of the geometric parameters of the structures on the acceleration gradients was also investigated. A study of changes in the acceleration gradients of structures, when applying a gold coating on these types of structures, has been carried out.Представлено дослідження темпів прискорення методом чисельного моделювання для діелектричних лазерних прискорювачів на ЧІП-структурах із одностороннім лазерним збудженням на довжині хвилі 800 нм. Відстань пучка електронів 200 та 400 нм. Також досліджено вплив геометричних параметрів структур на темпи прискорення. Проведено дослідження зміни градієнтів прискорення структур при нанесенні золотого покриття на дані типи структур.Представлено исследование темпов ускорения методом численного моделирования для диэлектрических лазерных ускорителей на ЧИП-структурах с односторонним лазерным возбуждением на длине волны 800 нм. Расстояние пучка электронов 200 и 400 нм. Также исследовано влияние геометрических параметров структур на темпы ускорения. Проведено исследование изменения градиентов ускорения структур, при нанесении золотого покрытия на данные типы структур