Papers by Keyword: P

Abstract: In this study, the input and output parameters of Phosphorus (P) for wheat production system were collected from the year 2000 to 2011 to evaluate the nutrient cycling and balances in North Central China, the Middle and Lower Reaches of the Yangtze River and Northwest China. The results showed that the P fertilizer application rates for each region were 44.5, 39.7 and 42.3 kg P/ha, the P brought from previous crop were 14.8, 1.6 and 2.6 kg/ha, and brought from seeding were 1.5, 1.0 and 0.9 kg/ha, respectively. The P input from atmospheric deposition and irrigation were considered zero. The P uptake by harvest in above-ground plant in North Central China, the Middle and Lower Reaches of the Yangtze River and Northwest China were 41.2, 53.2 and 17.0 kg/ha. As a result, the P balance in North Central China and Northwest China were both showing surplus by 19.6 and 28.8 kg/ha, and in the Middle and Lower Reaches of the Yangtze River showed deficiency. It is suggested that we need to adjust the P fertilizer input in China, in order to maintain the sustainable soil fertility and avoid the negative impact on the environment.

Abstract: In this paper, the effects of contents of Fe and P on the microstructures and properties of Cu-Cr-Zr resistance spot welding electrode alloys have been studied by means of electrical conductivity and hardness measurements and optical microscopy. By the addition of 2.5%Fe and 0.03P%, after being aged for 6h, the Cu-Cr-Zr-Fe-P alloy has the highest hardness of 125HV. At this time, the electrical conductivity of alloy is 60%IACS. The addition of 0.1%Zn contributes very little to hardness and electrical changes.

Abstract: A series of microcalorimetric experiments were performed to evaluate the As(III), Fe(II), P and their joint effects by analyzing the thermodynamic parameters, microbial growth rate constant k, total heat evolution QT, inhibitory ratio I and highest heat flow Pmax. They were obtained from power-time curves of the growth of P. fluorescens. The effect of mixed As(III), Fe(II) and P were moderate, compared with control, single As(III) or Fe(II). In addition, FT-IR spectra of dry P. fluorescens after the adsoption of As(III) and Fe(II) and their mixture showed that Fe influenced the C-H bonds of the functional groups on the cellwall, the As(III) caused litter effect.

Abstract: The effects of phosphorous on the anti-oxidation of SnPb solder and the mechanism were investigated. The surface oxidation behavior of Sn63Pb37 solder in the liquid state was observed by comparing the color of the molten solder and the effects of the temperature on the oxidation resistance of solder Sn63Pb37-P is conduced by skimming and weighting the oxidation dross. OM, SEM and EDS were used to analyze the anti-oxidation performance and mechanism. The results show that Sn63Pb37 solder with 0.019wt.% P can maintain smooth and brightly longer under 260°C, and produce less oxide slag. It is found that phosphorous is needle-like and concentrate on the surface of the solder and oxide film. At 260 °C, the additional element P suppresses impurity element Fe forming oxide. The additional element P will engage in the forming of oxide film, and improve the structure and mechanical property of oxide film to achieve the antioxidant effect. If heated to 380°C, the oxidation resistance of molten Sn63Pb37-P alloy was greatly worsen, instead.

Abstract: The discharge of urban sewage and agricultural non-point source pollutants is the main reason causing eutrophication in gullies in most cities of northern China. Based on a careful analysis on the ecological structure and ecological characteristics of a gully, this article preliminarily studies the interception and degradation mechanisms of nitrogen pollutants by the gully. Meanwhile, to take gullies in Changchun as the object of the study, this article carries out an experiment on the interception effect of nitrogen pollutants by gullies. This experiment respectively establishes a control section in the upper and lower reaches of a gully, and takes water samples four times in each section from May to August to determine total nitrogen, total phosphorus, nitrate nitrogen, ammonia nitrogen and salinity. The result shows: the gully plays some role in the interception of pollutants; total phosphorus accounts for the largest interception in pollutants in the experimented gully section, with the relative interception rate of 27.46%, followed by ammonia nitrogen, with the interception rate of 21.80%, which is the result of the combined effects of aquatic plants, microorganisms and sediment in the gully.

Abstract: The quality and properties of steels may be affected due to the segregation of the alloying elements, even though the properties of steels can be improved by adding appropriate amount of alloying elements. Rapid solidification was regarded to be an effective method to reduce or eliminate the segregation of alloying elements. While the segregation of C, P and Mn was also observed in rapid solidified (in silicone oil) droplet carbon steels in this paper. The microstructures of rapid solidified droplets were rather fine. When the P content was less than about 0.09% (in mass) in low carbon steels, P did not show obvious segregation in rapid solidified droplet samples; when the P content raised up to about 0.5% in the samples, both P and Mn showed center segregation even though the content of Mn kept unchanged. So the alloying elements can segregate and even effect the distribution of other elements in rapid solidified steel samples. When the C content increased, the segregation of C was observed in high-C samples, while the segregation tendency is opposite to that of P in high-P samples. For all the droplet samples, the micro-hardness of high-P samples was also much higher than those samples with less P content.

Abstract: High-strength IF steel sheet has increasingly attracted more attention of steelmakers in recent years as it has the potential to lighten the weight of automobiles and save energy and lower the production cost. In this paper, the effect of processing parameters on microstructures and mechanical properties especially deep drawability of ferritic-rolled P-added high strength Ti-stabilized IF steels were investigated and the precipitates in the steels were also analyzed. The results show that lubricant condition has great influence on the r-value and deep drawability of high-strength IF steels. And with the decrease of rolling temperature in ferrite region, the deep drawability of steels is improved.

Abstract: Multiple P or S hot ion implantation to diamond substrates was performed at 800°C. Optical absorption spectra indicated that instantaneous annealing during hot ion implantation occurs. Temperature dependence of resistance demonstrated that a P as-implanted sample using a homoepitaxial diamond film substrate emerges a weak doping effect. Also on S implantation, a presence of a weak doping effect was observed in an as-implanted sample, but it was suggested that the dopant is not S itself but S and defect complex. However, post-implantation annealing resulted in high resistance of the samples and missing of such weak doping effects.