805 research outputs found

    On the Benign One-Pot Preparation of Nanoporous Copper Thin Films with Bimodal Chan-nel Size Distributions by Chemical Dealloying in an Alkaline Solution

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    Nanoporous copper (NPC) thin films with bimodal channel size distributions can be benignly fabricated by one-pot chemical dealloying of dual-phase Al 27 at Cu alloy with hypereutectic structure in the NaOH solution. The microstructure of these NPC thin films was characterized using X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis. The results show that these NPC thin films are composed of interconnected large-sized channels (100s of nm) with highly porous channel walls (10s of nm), in which large-sized channels resulting from entire dissolution of solid solution while small-sized those de-riving from part corrosion of intermetallics. Both large- and small-sized channels are 3D, open, and bicon-tinuous. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3520

    Preparation of Nanostructured Li2MnO3 Cathode Materials by Single-Step Hydrothermal Method

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    Nanosized (10~50 nm) cathode material Li2MnO3 was prepared for with MnSO4·H2O,KMnO4 and Li- OH aqueous solution as the precursor via single-step hydrothermal reaction by controlling the reaction time, proportion of processor, and the reagent concentration. The prepared materials were well crystallized and exhibited a monoclinic Li2MnO3 structure with a space group of C2/m phase. The electrochemical performance of the material was tested at current density of 60 mAg-1 (1/4 C) between 4.3V and 2.0 V at room temperature, showing good electrochemical properties with the initial discharge capacity of 243 mAh·g-1, because it was more exposed to the electrolyte due to its nanostructure. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3519

    Structure and Electrochemical Performance of Li[Li0.2Co0.4Mn0.4]O2 Cathode Material for Lithium Ion Battery by Co-precipitation Method

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    The nano-structured Li[Li0.2Co0.4Mn0.4]O2 cathode material is synthesized by a co-precipitation method. X-ray diffraction shows that the synthesized material has a hexagonal α-NaFeO2 type structure with a space group R-3m. Scanning electron microscopy and transmission electron microscopy images show the homogeneous distribution with 100-200 nm. X-ray photoelectron spectroscopy results indicate that the oxi-dation states of Co and Mn in Li[Li0.2Co0.4Mn0.4]O2 are present in trivalence and tetravalence, respectively. The charge-discharge curves and cycling performance are analyzed in detail. The initial charge and dis-charge capacities are respectively 236.5 mAh g-1 and 140.3 mAh g-1 at the current density of 100 mA g-1 in the voltage range of 2.0-4.6 V. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3520

    Multi-neutron transfer coupling in sub-barrier 32S+90,96Zr fusion reactions

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    The role of neutron transfers is investigated in the fusion process below the Coulomb barrier by analyzing 32S+90Zr and 32S+96Zr as benchmark reactions. A full coupled-channel calculation of the fusion excitation functions has been performed for both systems by using multi-neutron transfer coupling for the more neutron-rich reaction. The enhancement of fusion cross sections for 32S+96Zr is well reproduced at sub-barrier energies by NTFus code calculations including the coupling of the neutron-transfer channels following the Zagrebaev semiclassical model. We found similar effects for 40Ca+90Zr and 40Ca+96Zr fusion excitation functions.Comment: Minor corrections, 11 pages, 4 figures, Fusion11 Conference, Saint Malo, France, 2-6 mai 201

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

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    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

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

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    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
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