Diffuse export of nutrients under different land uses in the irrigation area of lower Beiyunhe River (China)

AbstractNon-point source pollution is serious in the agriculture watershed of China. Understanding the characteristics of rainfall-runoff from agriculture watershed can provide theoretical support for controlling non-point source pollution. In this study, we investigated runoff characteristics of eight indices (dissolved total N, NO3--N, NH4+-N, total phosphorus, dissolved total phosphorus, particulate phosphorus, total organic carbon, COD) from three types of land uses, including farmland, forest and village in the downstream irrigation area of the Beiyunhe River basin. The results showed that the event mean concentrations (EMCs) of total dissolved N in village, farmland and forestland were 17.81mg/L, 12.68mg/L and 3.14mg/L, respectively. EMC of total phosphorus in the order: farmland (0.44mg/L) > village (0.22mg/L) > forestland (0.17mg/L). EMC of COD in the order: farmland (45.07mg/L) > forestland (27.06mg/L) > village (18.03mg/L). The changes in the nutrients concentrations of the runoff water over a rainfall event indicated that the transports of the nutrients are similar among various land use types. The instantaneous concentrations of TN, NH4+-N, and NO3--N were high in the initial period of runoff, tend to decreasing with rainfall continuing, and increase in later period. Phosphorus concentration with time variation was not obvious among three land use types. The phosphorus species with high proportion in the total phosphorus was particle P (accounting for 75%) in forestland, dissolve P (79%) in farmland, and particle P (48%) and dissolve P (52%) in village. The curves of COD and TOC had been shown as high in the initial period of runoff, tending to increasing with rainfall continuing, and decrease in the later period. First-flush of all the indices were obvious in all three land use types with the rank of village > forestland > farmland. In village, all of the pollutions have taken place the phenomenon of first flush, while in farmland, pollutions tended to uniformly distribute or dilution throughout the storm event

Attribution of climate change, vegetation restoration, and engineering measures to the reduction of suspended sediment in the Kejie catchment, southwest China

10.5194/hess-18-1979-2014Hydrology and Earth System Sciences1851979-199

Characteristics and Sensing Properties of the La1-xNdxCo0.3Fe0.7O3 System for CO Gas Sensors

A series of nanostructured La1-xNdxCo0.3Fe0.7O3 perovskite-type (x ranging from 0 to 1) were prepared using the co-precipitation method. CO gas sensing properties of La1-xNdxCo0.3Fe0.7O3 sensors were performed. La0.7Nd0.3Co0.3Fe0.7O3 sensor showed the highest response at 250 °C (S=52.8)

A Study on the Sudden Death of Entanglement

The dynamics of entanglement and the phenomenon of entanglement sudden death (ESD) \cite{yu} are discussed in bipartite systems, measured by Wootters Concurrence. Our calculation shows that ESD appears whenever the system is open or closed and is dependent on the initial condition. The relation of the evolution of entanglement and energy transfer between the system and its surroundings is also studied.Comment: Comments and criticism are welcome. Accepted by Phys. Lett.

Residual Strains of Filter Materials Reinforced with Grid Inclusions under Cyclic Loading

Reinforcement technology is widely used for filter dams in high-seismicity zones. The effect of reinforcement on deformation and safety is evaluated, and it is one of the primary objectives to be investigated in filter engineering. Residual strains of reinforced filter materials were experimentally studied using a triaxial apparatus. The effect of reinforcement mesh sizes, confining pressures, and cyclic loading modes on residual strains was analyzed. The results show that the reinforcement reduces residual strains of filter materials. Both residual shear and volume strains are determined. Based on the test results, one of the possible mechanisms of the reinforcement effect on residual strains is proposed..Технология армирования широко используется для упрочнения фильтрующих плотин в зонах высокой сейсмичности. Оценено влияние армирования на их деформирование и надежность, что является одной из основных проблем, рассматриваемых при разработке фильтровальных материалов. Выполнены экспериментальные исследования по оценке остаточных деформаций упрочненных фильтровальных материалов с использованием трехосного устройства. Проанализировано влияние размера ячеек армирующей сетки, ограничивающих давлений и режимов циклического нагружения на остаточные деформации. Результаты показывают, что армирование уменьшает остаточную деформацию фильтровальных материалов. Определены остаточные сдвиговые и объемные деформации. На основании результатов испытаний предложен один из возможных механизмов влияния упрочнения на остаточные деформации

Charge ordering in charge-compensated Na0.41CoO2Na_{0.41}CoO_2 by oxonium ions

Charge ordering behavior is observed in the crystal prepared through the immersion of the $Na_{0.41}CoO_2$ crystal in distilled water. Discovery of the charge ordering in the crystal with Na content less than 0.5 indicates that the immersion in water brings about the reduction of the $Na_{0.41}CoO_2$. The formal valence of Co changes from +3.59 estimated from the Na content to +3.5, the same as that in $Na_{0.5}CoO_2$. The charge compensation is confirmed to arise from the intercalation of the oxonium ions as occurred in the superconducting sodium cobalt oxide bilayer-hydrate.\cite{takada1} The charge ordering is the same as that observed in $Na_{0.5}CoO_2$. It suggests that the Co valence of +3.5 is necessary for the charge ordering.Comment: 5 pages, 4 figure

Effect of reducing 3.2% dietary protein level on the growth performance and immunity of Nile tilapia (Oreochromis niloticus) with supplementation of multi amino acids

Reducing dietary protein content in fish feeds will reduce cost of production if growth performance can be maintained. In this study, we assessed the effects of reduced dietary protein content from 33.5% to 27.4% with ideal amino acids profile on the growth, immune parameters, intestinal microvilli length and total ammonia nitrogen discharge of tilapia. After 8 weeks of feeding, growth performance and feed efficiency were not affected by reducing dietary protein content from 33.5% to 30.3%, while fish fed 27.4% CP had the lowest weight gain. Total ammonia nitrogen discharged into the water 9 hours after the feeding was decreased by about 35%. Serum lysozyme activity, blood respiratory burst activity and serum ACH50 were not significantly affected by dietary protein content. Fold height, enterocyte height and microvillus height of proximal and middle intestine were significantly increased with reducing of dietary protein. Results indicated that 3.2% dietary protein content can be reduced, which had no effects on growth performance and immunity of Nile tilapia in practical diet

Surface structure and solidification morphology of aluminum nanoclusters

Classical molecular dynamics simulation with embedded atom method potential had been performed to investigate the surface structure and solidification morphology of aluminum nanoclusters Aln (n = 256, 604, 1220 and 2048). It is found that Al cluster surfaces are comprised of (111) and (001) crystal planes. (110) crystal plane is not found on Al cluster surfaces in our simulation. On the surfaces of smaller Al clusters (n = 256 and 604), (111) crystal planes are dominant. On larger Al clusters (n = 1220 and 2048), (111) planes are still dominant but (001) planes can not be neglected. Atomic density on cluster (111)/(001) surface is smaller/larger than the corresponding value on bulk surface. Computational analysis on total surface area and surface energies indicates that the total surface energy of an ideal Al nanocluster has the minimum value when (001) planes occupy 25% of the total surface area. We predict that a melted Al cluster will be a truncated octahedron after equilibrium solidification.Comment: 22 pages, 6 figures, 34 reference

Geometric Phase and Quantum Phase Transition in the Lipkin-Meshkov-Glick model

The relation between the geometric phase and quantum phase transition has been discussed in the Lipkin-Meshkov-Glick model. Our calculation shows the ability of geometric phase of the ground state to mark quantum phase transition in this model. The possibility of the geometric phase or its derivatives as the universal order parameter of characterizing quantum phase transitions has been also discussed.Comment: 6 pages and to be published in Phys.Lett.