Papers by Keyword: Nitrogen

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Authors: Yo Tomota, K. Ikeda, Mayumi Ojima, Junichi Suzuki, Takashi Kamiyama
Authors: Chi Yang
Abstract: The reaction of N2 with lithium at electrode in lithium ion batteries was reported in this paper. At room temperature, N2 can react with lithium, mainly at anode, to form Li3N in an electrochemical system very easily during charge-discharge cycles. Li3N has been characterized by XPS. Experimental results also revealed that the higher of the current density and higher of the temperature resulted in quicker of the nitrogen-fixation reaction. The reaction can be brought about almost completely in the lithium ion batteries at room temperature. This could be a new method for preparation of Li3N at room temperature.
Authors: Wen Xia Xie, Kun Jie Zhu, Hui Na Du
Abstract: As a supplementary theory of ecological system research, ecological stoichiometry has been applied to many research fields of wetland ecosystems at home and abroad. This article reported carbon nitrogen phosphorus element stoichiometry of soil, vegetation, among different components and after artificial disturbance in wetland ecosystems. Research showed that wetland ecological stoichiometry characteristics have important influences on the change and their interaction of carbon nitrogen phosphorus in the whole system and the internal mechanism of the carbon nitrogen phosphorus balance of wetland ecosystems. At the same time, it has provided an important reference for the management and protection of wetland ecological system.
Authors: Peter Deák, B. Aradi, Adam Gali, Uwe Gerstmann, Wolfgang J. Choyke
Authors: Jae Kyoung Shin, Soo Woo Nam, Soo Chan Lee
Abstract: To understand the effects of nitrogen on high temperature, creep-rupture tests have been conducted at 973 and 1073K for 18Cr-9Ni austenitic stainless steels with 0.14 and 0.08wt% nitrogen contents. It is observed that creep-rupture life of 18Cr-9Ni-0.14N steel is longer than that of 18Cr-9Ni-0.08N steel. To verify the difference in creep-rupture life between two alloys, scanning electron microscope and transmission electron microscopy are used to observe the microstructure. From the observations, it is known that the Cr-rich carbides are precipitated mainly at the grain boundary. Comparing the ratio of the linear density of the precipitate particles, the higher nitrogen content is, the less carbide is precipitated. Nitrogen might retard the formation of carbides at the grain boundary and reduce the density of cavity sites which are one of the main grain boundary damages.
Authors: Darren M. Hansen, Gil Yong Chung, Mark J. Loboda
Abstract: A detailed understanding of the incorporation of N2 gas during PVT growth of SiC is required to achieve high performance, low resistivity n+ SiC substrates necessary for power device applications. In this report, nitrogen incorporation is investigated for growth of 4H SiC crystals from 2” to 3” diameter in conditions ranging from unintentionally doped to low resistivity (0.015 - cm). For a wafer in a particular boule a resistivity uniformity of ± 5% is typical although the uniformity decreases when the wafer orientation is cut off axis from the bulk growth direction. Within a boule growth, the nitrogen incorporation is found to be a function of growth time. As growth continues, the resistivity of wafers cut further from the seed increases. A typical 3” on axis sliced wafer has a within wafer resistivity uniformity of 5% compared with an average seed to tail variation of 10%. Due to the axial resistivity gradient the within wafer resistivity uniformity of off axis sliced wafers is 8%. These axial and radial gradients are thought to be a function of the changing C/Si ratio during growth. Nitrogen incorporation as a function of PVT geometry, N2 partial pressure, and growth temperature are investigated and discussed. In particular, nitrogen incorporation is found to depend on the crucible size and nitrogen partial pressure, but is not strongly dependent on the absolute growth temperature, for growth temperature ranging over 150°C. Modeling of PVT growth shows the axial resistivity gradient can be linked with a change in the C/Si ratio versus time. Trends and N2 gas incorporation behavior will be discussed using resistivity mapping, SIMS, and Hall effect data.
Authors: Yi Xin Xu, Hua Yong Zhang, Xiang Xu, Jing Zhao, Fei Li
Abstract: Eco-exergy which is a thermodynamic indicator is applied to assess the ecosystem health status of QiXing Lake. And effects of nitrogen and phosphorus on ecosystem health status have been investigated. The results indicate that the ecosystem which contains macrophytes has the better health status than that does not contain macrophytes when they have the same concentration of nitrogen or phosphorus. The ecosystem health status decreased as the concentration of total nitrogen increased when the ecosystem contains macrophytes. However, the ecosystem health status has not significant change as the concentration of total nitrogen increased when the ecosystem does not contains macrophytes. It has the same law for total phosphorus.
Authors: Su Chen, Lei Chao, Ning Chen, Lin Shan Wang, Xin Liu, Li Na Sun
Abstract: In this experiment, water hyacinth presents a good purification effect in five kinds of eutrophic waters with initial total nitrogen (TN) and total phosphorus (TP) concentrations in between 8.34~20.45 mg/L and 0.78~1.51 mg/L. After two weeks of purification, TN and TP concentrations of eutrophic waters are reduced to 1.78~5.68 mg/L and 0.25~0.312 mg/L, and TN and TP removal rates are 72.22~78.65% and 67.95~79.34%. Water hyacinth’s TN removal rate decreases as TN initial concentration increases; TP removal rate increases as TP initial concentration increases. Water hyacinth’s average total biomass in eutrophic water has increased by 0.944~1.084 kg/m2, and the average bio-dry-weight has increased by 0.0470~0.0547 kg/m2. The average total biomass and average bio-dry-weight of water hyacinth increase as the eutrophication deepens.
Authors: Jun Hu Liu, Bart Blanpain, Patrick Wollants
Abstract: TiB2 coatings were plasma sprayed in air and were studied by XPS. There are five elements in the top surface of the studied coatings, namely, B, C, N, O and Ti. Oxygen pick-up in the coatings results in formation of oxides of boron and titanium. Nitrogen was shown to exist in N-Ti and O-N-Ti in the coating. Depending on the spraying parameters, mono-boride as well as di-boride was also detected in the studied coatings. With careful peak fitting it was shown that oxygen may exist in the coating as dissolved atomic O in addition to as lattice oxygen in the oxide of boron and titanium.
Authors: Alexander Mattausch, M. Bockstedte, Oleg Pankratov
Abstract: We investigated the the interstitial configurations of the p-type dopants boron and aluminum and the n-type dopants nitrogen and phosphorus in 4H-SiC by an ab initio method. In particular, the energetics of these defects provides information on the dopant migration mechanisms. The transferability of the earlier results on the boron migration in 3C-SiC to the hexogonal polytype 4H-SiC is verified. Our calculations suggest that for the aluminum migration a kick-out mechanism prevails, whereas nitrogen and phosphorus diffuse via an interstitialcy mechanism.
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