1,942 research outputs found

    Relationship of land use/cover on water quality in the Liao River basin, China

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    AbstractA total of 76 sampling sites were selected in the Liao River basin (21.9×104km2). During the period of 2009-2010, 58 water samples were collected in 2010 and 42 were collected in 2009, physical-chemical variables were analyzed to investigate their spatial-temporal variability in particular the relationship with land use /cover. The results indicated that physical and chemical properties showed obvious spatial heterogeneity in the Liao River basin. Taizi River and Hun River are located in the southeast of the basin, the water quality for two sub-basins: water quality in upstream is better than that in downstream, water quality level in downstream was classified into IV-V. There were no obvious features in the East Liao River basin, water quality in downstream was classified into III level. West Liao River run for many years, water quality was classified into IV. Big Liao River basin was located in middle and east of the Liao River basin. Water quality was classified into V. Correlation and regression analysis indicated that BOD5, COD, sediment, hardness and nitrate–nitrogen (NO3−–N), total dissolved particular (TDP) were significantly related to land use for forest and agriculture

    Assessment of β-D-Glucosidase Activity from Two Typical Strains of the Lactic Acid Bacteria, Oenococcus oeni, in China

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    β-D-glucosidase (βG) is one of the most interesting glycosidases for the hydrolysis of glycoconjugatedprecursors to release active aromatic compounds in musts and wines. Oenococcus oeni strains SD-2a and31MBR are widely used in Chinese wines to reduce the acidity. In the present study, the βG activity of thetwo strains was localised and partially characterised using synthetic substrate. The activity occurred inwhole cells, sonication supernatants and debris, but not in the culture supernatants for both strains. Wholecells of strain SD-2a possessed greater βG activity, while strain 31MBR showed higher enzyme activity inthe sonication supernatants. Strain 31MBR exhibited higher total enzyme activity than strain SD-2a. Theoptimum temperatures for βG from the two strains were 40ºС at pH 3.5 and 50ºС at pH 5.0, respectively.Ethanol at low concentrations had a positive effect on βG activity in both strains, while a wine-like pH (3.5)decreased the enzyme activity to a great extent. Whole cells of strain SD-2a showed the highest activityamong all samples tested under wine-like conditions. Thus, strain SD-2a proved to have potential foraroma improvement in winemaking

    Зарубіжний досвід стимулювання розвитку малого та середнього бізнесу

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    У статті визначено основні сучасні центри ефективних технологій підтримки підприємництва, проведено аналіз особливостей державної політики розвитку малого та середнього бізнесу в США, визначено ефективні методи стимулювання розвитку малого та середнього бізнесу в умовах кризи.В статье определены основные современные центры эффективных технологий поддержки предпринимательства, проведен анализ особенностей государственной политики развития малого и среднего бизнеса в США, определены эффективные методы стимулирования развития малого и среднего бизнеса в условиях кризиса.In the article the main modern centers of effective technologies of supporting of business development are identified, the features of the state policy of small and medium businesses development in the U.S. are analyzed; most effective methods of stimulating of small and medium businesses development in conditions of crisis are identified

    Analysis of the dynamic changes in the soft palate and uvula in obstructive sleep apnea-hypopnea using ultrafast magnetic resonance imaging

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    Apnea and the respiratory cycle are dynamic processes in obstructive sleep apnea-hypopnea (OSAH), which occur only during sleep. Our study aimed to observe the dynamic changes in the soft palate and the uvula during wakefulness and sleep using ultrafast magnetic resonance imaging (UMRI) to provide reference data for the pathogenesis and treatment of OSAH. The dynamic changes in the soft palate and uvular tip of 15 male patients (average age: 50.43 ± 9.82 years) with OSAH were evaluated using UMRI of the upper airway while asleep and awake after 1 night of sleep deprivation. A series of midline sagittal images of the upper airway were obtained. The distance from the center of the soft palate to the x-axis (an extended line from the anterior nasal spine to the posterior nasal spine), from the uvular tip to the x-axis, from the center of the soft palate to the y-axis (a perpendicular line from the center of the pituitary to the x-axis), and from the uvular tip to the y-axis (designated as PX, UX, PY, and UY, respectively) were measured during sleep and wakefulness. The minimum PX, PY, UX, and UY were shorter during sleep than during wakefulness, whereas the maxima were longer during sleep (P < 0.01), the differences between the maximum and minimum PX, PY, UX, and UY were larger during sleep (P < 0.01). The upward, downward, forward, and backward ranges of movement of the soft palate and the uvular tip were larger during sleep in OSAH patients. This increased compliance may trigger each airway obstructive event

    On Vanishing Theorems For Vector Bundle Valued p-Forms And Their Applications

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    Let F:[0,)[0,)F: [0, \infty) \to [0, \infty) be a strictly increasing C2C^2 function with F(0)=0F(0)=0. We unify the concepts of FF-harmonic maps, minimal hypersurfaces, maximal spacelike hypersurfaces, and Yang-Mills Fields, and introduce FF-Yang-Mills fields, FF-degree, FF-lower degree, and generalized Yang-Mills-Born-Infeld fields (with the plus sign or with the minus sign) on manifolds. When F(t)=t,1p(2t)p2,1+2t1,F(t)=t, \frac 1p(2t)^{\frac p2}, \sqrt{1+2t} -1, and 112t,1-\sqrt{1-2t}, the FF-Yang-Mills field becomes an ordinary Yang-Mills field, pp-Yang-Mills field, a generalized Yang-Mills-Born-Infeld field with the plus sign, and a generalized Yang-Mills-Born-Infeld field with the minus sign on a manifold respectively. We also introduce the EF,gE_{F,g}-energy functional (resp. FF-Yang-Mills functional) and derive the first variational formula of the EF,gE_{F,g}-energy functional (resp. FF-Yang-Mills functional) with applications. In a more general frame, we use a unified method to study the stress-energy tensors that arise from calculating the rate of change of various functionals when the metric of the domain or base manifold is changed. These stress-energy tensors, linked to FF-conservation laws yield monotonicity formulae. A "macroscopic" version of these monotonicity inequalities enables us to derive some Liouville type results and vanishing theorems for pp-forms with values in vector bundles, and to investigate constant Dirichlet boundary value problems for 1-forms. In particular, we obtain Liouville theorems for FF-harmonic maps (e.g. pp-harmonic maps), and FF-Yang-Mills fields (e.g. generalized Yang-Mills-Born-Infeld fields on manifolds). We also obtain generalized Chern type results for constant mean curvature type equations for pp-forms on Rm\Bbb{R}^m and on manifolds MM with the global doubling property by a different approach. The case p=0p=0 and M=RmM=\mathbb{R}^m is due to Chern.Comment: 1. This is a revised version with several new sections and an appendix that will appear in Communications in Mathematical Physics. 2. A "microscopic" approach to some of these monotonicity formulae leads to celebrated blow-up techniques and regularity theory in geometric measure theory. 3. Our unique solution of the Dirichlet problems generalizes the work of Karcher and Wood on harmonic map

    Experimental and Numerical Analysis of Normal and Lateral High-Velocity Impacts on Carbon Fiber-Reinforced Polymer Laminates

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    This paper examines the effects of normal and lateral high-speed impacts on carbon fiber-reinforced polymer laminates. Experimental tests were conducted at varying velocities (120–200 m/s), and the differing damage modes between normal and lateral impacts were analyzed. Dynamic finite element analysis was performed to simulate the damage process using the finite element software ABAQUS. The simulation shows a good correlation with the experimental results

    Elevated-temperature impact toughness of Mg–(Gd, Y)–Zr alloy

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    The Charpy impact results for Mg–10Gd–3Y–0.5Zr and Mg–11Y–5Gd–2Zn–0.5Zr alloys at various temperatures showed that Mg–10Gd–3Y–0.5Zr was more sensitive to temperature. The increase in impact toughness with temperature was related to the blunt crack-tip at high temperatures. The delamination and local melt of matrix were responsible for the brittle-to-ductile transition of GW103 alloy. The branch and bridging of cracks resulting from ordered phases played an import role in the change in fracture mode from cleavage fracture to quasi-cleavage and dimple-fracture for WGZ1152 alloy

    Magnetic phase diagram in Eu1x_{1-x}Lax_xFe2_2As2_2 single crystals

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    We have systematically measured resistivity, susceptibility and specific heat under different magnetic fields (H) in Eu1x_{1-x}Lax_xFe2_2As2_2 single crystals. It is found that a metamagnetic transition from A-type antiferromagnetism to ferromagnetism occurs at a critical field for magnetic sublattice of Eu2+Eu^{2+}. The jump of specific heat is suppressed and shifts to low temperature with increasing H up to the critical value, then shifts to high temperature with further increasing H. Such behavior supports the metamagnetic transition. Detailed H-T phase diagrams for x=0 and 0.15 crystals are given, and possible magnetic structure is proposed. Magnetoresistance measurements indicate that there exists a strong coupling between local moment of Eu2+Eu^{2+} and charge in Fe-As layer. These results are very significant to understand the underlying physics of FeAs superconductors.Comment: 5 pages, 4 figure
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