Journal articles: 'Zebulon area, N.C'

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Kar, Ashish Kumar, and Rajendra Srivastava. "Selective synthesis of Cu–Cu2O/C and CuO–Cu2O/C catalysts for Pd-free C–C, C–N coupling and oxidation reactions." Inorganic Chemistry Frontiers 6, no. 2 (2019): 576–89. http://dx.doi.org/10.1039/c8qi01198b.

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Cu-BTC MOF provides highly nanoporous Cu–Cu₂O/C and CuO–Cu₂O/C materials having active Cu phases with a high surface area and pore volume for efficient and sustainable catalysis.

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Bosdet, Michael J. D., and Warren E. Piers. "B-N as a C-C substitute in aromatic systems." Canadian Journal of Chemistry 87, no. 1 (January 1, 2009): 8–29. http://dx.doi.org/10.1139/v08-110.

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The substitution of isoelectronic B–N units for C–C units in aromatic hydrocarbons produces novel heterocycles with structural similarities to the all-carbon frameworks, but with fundamentally altered electronic properties and chemistry. Since the pioneering work of Dewar some 50 years ago, the relationship between B–N and C–C and the wealth of parent all-carbon aromatics has captured the imagination of organic, inorganic, materials, and computational chemists alike, particularly in recent years. New applications in biological chemistry, new materials, and novel ligands for transition-metal complexes have emerged from these studies. This review is aimed at surveying activity in the area in the past couple of decades. Its organization is based on ring size and type of the all-carbon or heterocyclic subunit that the B–N analog is derived from. Structural aspects pertaining to the retention of aromaticity are emphasized, along with delineation of significant differences in physical properties of the B–N compound as compared to the C–C parent.Key words: boron-nitrogen heterocycles, aromaticity, organic materials, main-group chemistry.

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Li, Bao Qin, and B. A. Taylor. "On the Bezout problem and area of interpolating varieties in C n." American Journal of Mathematics 118, no. 5 (1996): 989–1010. http://dx.doi.org/10.1353/ajm.1996.0041.

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Asfahani, Jamal. "Characterization of Ar-Rassafeh Badyieh area (Area-2), Syria by using the airborne gamma-ray spectrometric and fractal modelling techniques." Contributions to Geophysics and Geodesy 49, no. 4 (December 1, 2019): 459–78. http://dx.doi.org/10.2478/congeo-2019-0024.

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Abstract The available aerial gamma-ray spectrometric data of Ar-Rassafeh Badyieh area (Area-2) are used herein for geological interpretations and mapping purposes. Those data are interpreted by the concentration-number (C-N) fractal modelling technique, with the use of log-log graphs. According to C-N model, different radioactive ranges of TC, eU, eTh, and K have been isolated. Those ranges are thereafter used to characterize the lithological outcrops in the study area. The radioactive signatures of all the outcrops in Area-2 have been discussed and documented through establishing the C-N maps of TC, eU, eTh, and K, and benefiting of the available geological map. The C-N fractal modelling technique proves its efficacy, where radioactive and lithological boundaries of outcrops are in concordance. The case study presented in this paper shows the importance and the role of airborne gamma-ray spectrometric and fractal modelling techniques to support the geological mapping and the interpretations in geological context, particularly when the study region is rugged and difficult to be accessed.

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Yoo, Yoon Jae. "Area Integral Associated with Singular Measures on the Unit Sphere on $C^n$." Rocky Mountain Journal of Mathematics 25, no. 2 (June 1995): 815–25. http://dx.doi.org/10.1216/rmjm/1181072251.

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Cezar, Adrielle M., Leila M. Pessoa, and Cibele R. Bonvicino. "Morphological and genetic diversity in Callithrix hybrids in an anthropogenic area in southeastern Brazil (Primates: Cebidae: Callitrichinae)." Zoologia 34 (July 28, 2017): 1–9. http://dx.doi.org/10.3897/zoologia.34.e14881.

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Two species of Callithrix, C. jacchus (Linnaeus, 1758) and C. penicillata (É. Geoffroy, 1812), are considered invasive in Rio de Janeiro. This study determined the genetic and morphological diversity and verified the species involved in the hybridization of 10 individuals from the municipalities of Silva Jardim (N = 9) and Rio das Ostras (N = 1). We compared the external morphology and skull of C. jacchus (N = 15) and C. penicillata (N = 14) specimens deposited in the collection of the National Museum of Rio de Janeiro (MN- UFRJ). Phylogenetic (maximum likelihood and Bayesian inference) and phylogeographical analyses (network analysis) were performed based on cytochrome b sequences. These analyses included hybrids from the metropolitan region of Rio de Janeiro (N = 3), C. penicillata (N = 2), C. jacchus (N = 2), C. geoffroyi (N = 2), C. kuhlii (N = 2), C. aurita (N = 1), and as outgroups, Mico emiliae (N = 1) and Saguinus mystax (N = 1). The pelage and skull characters of most hybrids were more closely related to C. jacchus. Skull morphometric analysis revealed an intermediate state for the hybrids. Phylogenetic analyses revealed a high similarity between the hybrids and C. penicillata. Six haplotypes of hybrids were identified. Network analysis including them and C. penicillata recovered the topology generated by phylogenetic analysis. The results corroborate that C. jacchus and C. penicillata participate in the hybridization process. There was no geographic structure between hybrids from the coastal lowlands and from the metropolitan region of Rio de Janeiro.

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Wick, Bruce, and Ronald Gall. "Refining decisions on which primary care patients to screen for glaucoma." Canadian Journal of Optometry 71, no. 5 (October 1, 2009): 26. http://dx.doi.org/10.15353/cjo.71.645.

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Introduction: Glaucoma, which is often accompanied by elevated intraocular pressure (IOP), causes progressive optic nerve atrophy and blindness. Among ocular structure parameters abnormalities in central corneal thickness (CCT), cup-to-disc (C/D) ratio, inter-eye C/D ratio asymmetry, optic disc area, and neuro-retinal rim area (N-RRA) appear to be highly correlated with glaucoma. We compare these specific ocular structures in a group of young normal pre-presbyopic patients and in a group of patients being treated for glaucoma. Methods: After written informed consent, 1433 consecutive normal, and 56 consecutive patients being treated for glaucoma were assessed by including age, race, sex, IOP (NCT), C/D ratio, optic disc area, N-RRA (Optos), central center thickness (CCT), and anterior chamber depth. Results: Combinations of findings in CCT, C/D ratio, C/D ratio asymmetry, disc area, and N-RRA (assessed by Z-score) were present in 65.52% of patients being treated for glaucoma and 22.96% of young normal patients. For young normal patients, overall average CCT was 550.37+/-39.47µm. Overall average C/D ratio was 0.39+/-0.11. Inter-eye C/D asymmetry was 0.02+/-0.06. Overall average disc area was 2.46+/-0.49mm2 (7863.54+/1630.42 pixels). Overall average N-RRA was 1.44+/-0.35mm2 (4785.88+/1161.14 pixels). C/D ratio increased modestly with disc area increase, an increase not associated with thinning N-RRA. Thin N-RRA was associated with small optic discs that had large C/D (t=-8.21, p=0.000, DF=93). There was a significant difference between young normal patients and patients being treated for glaucoma in CCT, C/D ratio, C/D ratio asymmetry, disc area, and N-RRA. Conclusion: More than one in five (22.96%) young normal patients has ocular structure findings similar to those found in patients being treated for glaucoma. These results will help refine decisions on which primary eye care patient to screen for glaucoma.

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Labra, Marcelo H., Paul C. Struik, Daniel F. Calderini, and Jochem B. Evers. "Leaf Nitrogen Traits in Response to Plant Density and Nitrogen Supply in Oilseed Rape." Agronomy 10, no. 11 (November 13, 2020): 1780. http://dx.doi.org/10.3390/agronomy10111780.

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Understanding the response of plant nitrogen (N) and carbon (C) economies in oilseed rape, as well as their role in defining phenotypic plasticity, is necessary for designing new strategies to optimize plant and canopy C assimilation to improve potential yield. This paper aims to elucidate the extent to which the interaction between N supply and plant population density alters N distribution in oilseed rape plant (Brassica napus L.) and whether this interaction changes plant investment in leaf area or leaf mass per area. Spring oilseed rape was grown at two rates of N supply (50 and 150 kg N·ha−1) and two plant population densities (50 and 150 plants·m−2). Photosynthesis, leaf area, leaf biomass, and N content of selected leaves were measured at 20% of flowers on main raceme open. The interaction between N supply and plant population density altered leaf N content per area, which is the main determinant of photosynthesis. This interaction also affected leaf mass per area, while N supply determined N content per unit leaf mass. These results suggest that the interaction between N supply and population density affects both nitrogen distribution and leaf mass per area, which could have important implications for light distribution and, therefore, for C assimilation at the plant level.

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Ling, Lloyd, Zulkifli Yusop, Wun-She Yap, Wei Lun Tan, Ming Fai Chow, and Joan Lucille Ling. "A Calibrated, Watershed-Specific SCS-CN Method: Application to Wangjiaqiao Watershed in the Three Gorges Area, China." Water 12, no. 1 (December 22, 2019): 60. http://dx.doi.org/10.3390/w12010060.

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The Soil Conservation Service curve number ( S C S-C N) method is one of the most popular methods used to compute runoff amount due to its few input parameters. However, recent studies challenged the inconsistent runoff results obtained by the method which set the initial abstraction ratio λ as 0.20. This paper developed a watershed-specific S C S-C N calibration method using non-parametric inferential statistics with rainfall–runoff data pairs. The proposed method first analyzed the data and generated confidence intervals to determine the optimum values for S C S- C N model calibration. Subsequently, the runoff depth and curve number were calculated. The proposed method outperformed the runoff prediction accuracy of the asymptotic curve number fitting method, linear regression model and the conventional S C S-C N model with the highest Nash–Sutcliffe index value of 0.825, the lowest residual sum of squares value of 133.04 and the lowest prediction error. It reduced the residual sum of squares by 66% and the model prediction errors by 96% when compared to the conventional S C S-C N model. The estimated curve number was 72.28, with the confidence interval ranging from 62.06 to 78.00 at a 0.01 confidence interval level for the Wangjiaqiao watershed in China.

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Meuriot, Frédéric, Marie-Laure Decau, Annette Morvan-Bertrand, Marie-Pascal Prud'Homme, François Gastal, Jean-Claude Simon, Jeffrey J. Volenec, and Jean-Christophe Avice. "Contribution of initial C and N reserves in Medicago sativa recovering from defoliation: impact of cutting height and residual leaf area." Functional Plant Biology 32, no. 4 (2005): 321. http://dx.doi.org/10.1071/fp04151.

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We studied the effects of stubble carbon / nitrogen (C / N) reserves or residual leaf area (RLA) on the contribution of taproot C / N reserves to shoot regrowth of Medicago sativa L. after cutting. The study assessed the effects of two cutting heights (6 and 15 cm), two RLAs (0 or 100%), and two initial C / N reserve levels (high N or low N) on forage production, nitrogen (N) distribution, and C / N reserve dynamics within stubble and taproot. Alfalfa forage production was mainly affected by the initial taproot C / N reserve levels. However, stubble initial organic reserves (and to a lesser extent the RLA) were also of particular importance during early regrowth. The increase of cutting height led to increased stubble C / N supply to regrowing shoots, which partly offset the negative effect on forage production and on taproot C / N reserve depletion. Unlike taproot reserves, the positive contribution of stubble organic reserves to shoot C / N supply was effective for a single defoliation–regrowth cycle. Alfalfa management strategies that increase cutting height (and RLA) during the penultimate harvest in autumn should be considered in cold regions with significant winter stress in order to improve alfalfa winter survival and persistence, as well as spring herbage regrowth.

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Bermejo, Jesús. "Roman peasant habitats and settlement in central Spain (1st c. B.C.–4th c. A.D.)." Journal of Roman Archaeology 30 (2017): 351–71. http://dx.doi.org/10.1017/s1047759400074158.

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The area under study comprises the Autonomous Community of Madrid, a highly urbanized modern region which coincides grosso modo with the N part of what used to be Carpetania. During the Early and Later Empire, it fell within the province of Hispania Citerior Tarraconensis, embracing the N part of the conventus Carthaginensis and the SW part of the conventus Caesaraugustanus. From the early days of municipalisation of the Hispanic provinces rural sites in this region belonged to the ager of three Latin municipia: Complutum, Titulcia, and Mantua Carpetanorum (fig. 1). While it is difficult to identify the precise limits of their agri, it seems probable that Complutum, as the most important urban centre in the region, would have had the largest territorium.

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Rohrer, Franziska E., and Ann-Kristin Larsson. "Twinning and defects in N-Nb2O5." Acta Crystallographica Section B Structural Science 56, no. 5 (October 1, 2000): 780–84. http://dx.doi.org/10.1107/s0108768100003657.

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N-Nb2O5 [C2/m (No. 12), a = 28.51, b = 3.830 and c = 17.48 Å, and β = 124.8°] has been investigated by means of selected-area electron diffraction (SAED) and high-resolution transmission electron microscopy (HRTEM). N-Nb2O5 is domain twinned, with the twin plane perpendicular to the c* axis. The domains are rather small and the domain twinning can sometimes be best explained as stacking faults. A second type of coherent twinning at an angle of 90° to the other two domain directions was also found. These domains are linked together by areas containing blocks of different sizes, similar to the disordered block arrangement observed in M-Nb2O5.

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Zhao, Yan, Fuli Wu, Xiaomin Fang, and Yibo Yang. "Topsoil C/N ratios in the Qilian Mountains area: Implications for the use of subaqueous sediment C/N ratios in paleo-environmental reconstructions to indicate organic sources." Palaeogeography, Palaeoclimatology, Palaeoecology 426 (May 2015): 1–9. http://dx.doi.org/10.1016/j.palaeo.2015.02.038.

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Thomas, R. Q., and M. Williams. "A model using marginal efficiency of investment to analyse carbon and nitrogen interactions in terrestrial ecosystems (ACONITE Version 1)." Geoscientific Model Development Discussions 7, no. 2 (April 25, 2014): 2525–80. http://dx.doi.org/10.5194/gmdd-7-2525-2014.

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Abstract. Carbon (C) and nitrogen (N) cycles are coupled in terrestrial ecosystems through multiple processes including photosynthesis, tissue allocation, respiration, N fixation, N uptake, and decomposition of litter and soil organic matter. Capturing the constraint of N on terrestrial C uptake and storage has been a focus of the Earth System modelling community. However there is little understanding of the trade-offs and sensitivities of allocating C and N to different tissues in order to optimize the productivity of plants. Here we describe a new, simple model of ecosystem C–N cycling and interactions (ACONITE), that builds on theory related to plant economics in order to predict key ecosystem properties (leaf area index, leaf C : N, N fixation, and plant C use efficiency) using emergent constraints provided by marginal returns on investment for C and/or N allocation. We simulated and evaluated steady-state ecosystem stocks and fluxes in three different forest ecosystems types (tropical evergreen, temperate deciduous, and temperate evergreen). Leaf C : N differed among the three ecosystem types (temperate deciduous < tropical evergreen < temperature evergreen), a result that compared well to observations from a global database describing plant traits. Gross primary productivity (GPP) and net primary productivity (NPP) estimates compared well to observed fluxes at the simulation sites. Simulated N fixation at steady-state, calculated based on relative demand for N and the marginal return on C investment to acquire N, was an order of magnitude higher in the tropical forest than in the temperate forest, consistent with observations. A sensitivity analysis revealed that parameterization of the relationship between leaf N and leaf respiration had the largest influence on leaf area index and leaf C : N. Also, a widely used linear leaf N-respiration relationship did not yield a realistic leaf C : N, while a more recently reported non-linear relationship performed better. A parameter governing how photosynthesis scales with day length had the largest influence on total vegetation C, GPP, and NPP. Multiple parameters associated with photosynthesis, respiration, and N uptake influenced the rate of N fixation. Overall, our ability to constrain leaf area index and have spatially and temporally variable leaf C : N helps address challenges for ecosystem and Earth System models. Furthermore, the simple approach with emergent properties based on coupled C–N dynamics has potential for use in research that uses data-assimilation methods to integrate data on both the C and N cycles to improve C flux forecasts.

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Lin, Xue, Rui Zhao, Yang Xi, Xiangyu Li, Junyou Shi, and Ning Yan. "Metal-free C 60 /CNTs/g-C 3 N 4 ternary heterostructures: synthesis and enhanced visible-light-driven photocatalytic performance." Royal Society Open Science 5, no. 5 (May 2018): 172290. http://dx.doi.org/10.1098/rsos.172290.

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A metal-free C 60 /CNTs/g-C 3 N 4 nanoheterostructure with excellent visible-light photocatalysis for rhodamine B (Rh B) degradation has been reported. Via a convenient low-temperature solution-phase method, g-C 3 N 4 nanosheets can serve as substrate for dispersion of C 60 /CNTs. The loading of C 60 /CNTs onto g-C 3 N 4 nanosheets surfaces significantly enhanced visible-light-driven photocatalytic activity of g-C 3 N 4 catalyst, for oxidation of organic pollutant (Rh B, 100%). Excellent photocatalytic properties of C 60 /CNTs/g-C 3 N 4 can be predominantly attributed to the intimate interfacial contact among constructing compounds, increased specific surface area and enhanced light adsorption efficiency resulted from C 60 /CNTs carbon materials. Particularly, the synergistic heterostructure interaction remarkably hinders the electron–hole pairs recombination, giving rise to significantly enhanced photocatalytic performance of C 60 /CNTs/g-C 3 N 4 in comparison with other counterparts.

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Thomas, R. Q., and M. Williams. "A model using marginal efficiency of investment to analyze carbon and nitrogen interactions in terrestrial ecosystems (ACONITE Version 1)." Geoscientific Model Development 7, no. 5 (September 12, 2014): 2015–37. http://dx.doi.org/10.5194/gmd-7-2015-2014.

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Abstract. Carbon (C) and nitrogen (N) cycles are coupled in terrestrial ecosystems through multiple processes including photosynthesis, tissue allocation, respiration, N fixation, N uptake, and decomposition of litter and soil organic matter. Capturing the constraint of N on terrestrial C uptake and storage has been a focus of the Earth System Modeling community. However, there is little understanding of the trade-offs and sensitivities of allocating C and N to different tissues in order to optimize the productivity of plants. Here we describe a new, simple model of ecosystem C–N cycling and interactions (ACONITE), that builds on theory related to plant economics in order to predict key ecosystem properties (leaf area index, leaf C : N, N fixation, and plant C use efficiency) based on the outcome of assessments of the marginal change in net C or N uptake associated with a change in allocation of C or N to plant tissues. We simulated and evaluated steady-state ecosystem stocks and fluxes in three different forest ecosystems types (tropical evergreen, temperate deciduous, and temperate evergreen). Leaf C : N differed among the three ecosystem types (temperate deciduous < tropical evergreen < temperature evergreen), a result that compared well to observations from a global database describing plant traits. Gross primary productivity (GPP) and net primary productivity (NPP) estimates compared well to observed fluxes at the simulation sites. Simulated N fixation at steady-state, calculated based on relative demand for N and the marginal return on C investment to acquire N, was an order of magnitude higher in the tropical forest than in the temperate forest, consistent with observations. A sensitivity analysis revealed that parameterization of the relationship between leaf N and leaf respiration had the largest influence on leaf area index and leaf C : N. A parameter governing how photosynthesis scales with day length had the largest influence on total vegetation C, GPP, and NPP. Multiple parameters associated with photosynthesis, respiration, and N uptake influenced the rate of N fixation. Overall, our ability to constrain leaf area index and allow spatially and temporally variable leaf C : N can help address challenges simulating these properties in ecosystem and Earth System models. Furthermore, the simple approach with emergent properties based on coupled C–N dynamics has potential for use in research that uses data-assimilation methods to integrate data on both the C and N cycles to improve C flux forecasts.

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Balister, Paul, Béla Bollobás, Amites Sarkar, and Mark Walters. "A critical constant for the k nearest-neighbour model." Advances in Applied Probability 41, no. 01 (March 2009): 1–12. http://dx.doi.org/10.1017/s0001867800003116.

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Let 𝒫 be a Poisson process of intensity 1 in a square S n of area n. For a fixed integer k, join every point of 𝒫 to its k nearest neighbours, creating an undirected random geometric graph G n,k . We prove that there exists a critical constant c crit such that, for c < c crit, G n,⌊c log n⌋ is disconnected with probability tending to 1 as n → ∞ and, for c > c crit, G n,⌊c log n⌋ is connected with probability tending to 1 as n → ∞. This answers a question posed in Balister et al. (2005).

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Gazal, Vinícius, Omar Bailez, and Ana Maria Viana-Bailez. "Termite (Isoptera) survey in urban area in Northern of Rio de Janeiro State, Brazil." Revista Colombiana de Entomología 45, no. 1 (September 30, 2019): e7813. http://dx.doi.org/10.25100/socolen.v45i0.7813.

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Most pest termites in urban areas in Brazil are exotic species, but native species are becoming an increasing problem. This study aimed to identify termite species infesting trees and houses in urban areas of Campos dos Goytacazes, in the north of Rio de Janeiro State. Trees in the streets of sixteen neighborhoods were inspected for termites. Inspections and interviews were also conducted to verify the occurrence of termites in houses. Termites were recorded in 17 % of the 1,307 trees surveyed. Coptotermes gestroi was the most frequent species (51% of infested trees), Nasutitermes corniger and Microcerotermes strunckii were present in 38 % and 14 % of infested trees, respectively, and Microcerotermes arboreus was the least common (1 %). Different termite species coexisted in 14 % of the infested trees (n = 31). Termite infestations were recorded in 26% of the surveyed households (n = 1,020). Four species were identified as causing damage: Cryptotermes brevis, C. gestroi, N. corniger, and M. strunckii. The most common species was C. brevis, affecting 133 residences (51 %). C. gestroi and N. corniger were less frequent, but they were responsible for more structural damage than C. brevis, which mainly attacked furniture.

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Menendez, L., H. Bester, J. M. Besson, and J. F. Bernard. "Parabrachial area: electrophysiological evidence for an involvement in cold nociception." Journal of Neurophysiology 75, no. 5 (May 1, 1996): 2099–116. http://dx.doi.org/10.1152/jn.1996.75.5.2099.

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1. Thirty-five percent of 120 neurons recorded extracellularly in the parabrachial (PB) area of anesthetized rats responded to a peripheral cold stimulus (0 degrees C). The cold-sensitive neurons were located in the lateral PB area, and most of those exhibiting a strong response to cold stimuli were inside or in close vicinity to the area receiving a high density of projections from superficial neurons of the dorsal horn. 2. The receptive fields for cold stimulation often were restricted to one or two parts of the body with a contralateral predominance for the limbs. No side predominance was observed for the face. 3. From a low spontaneous activity (10th percentile < median < 90th percentile: 0.1 < 1.5 < 5 Hz), the PB neurons responded to cold noxious stimuli (0 degree C water bath or waterjet, 20 s), without observable delay, with a sustained discharge. The mean maximal response to the stimulus was 16.1 +/- 1.2 Hz (mean +/- SE; n = 42). 4. About one-half (45%) of these cold-sensitive neurons were activated specifically by cold stimulation and did not respond or were inhibited by noxious heat and/or pinch. The remaining (55%) cold-sensitive neurons were also driven by heat and/or pinch. 5. The cold-sensitive neurons exhibited a clear capacity to encode cold stimuli in the noxious range: the stimulus-response function was always positive and monotonic from 30 to 0 degrees C; the mean curve was linear between 20 and 0 degrees C before plateauing between 0 to -10 degrees C; the mean threshold to cold stimulation was 17.1 +/- 1 degrees C (n = 21) and the mean t50 was 10.7 +/- 1.1 degrees C (n = 13). 6. The cold-sensitive neurons responded to intense transcutaneous electrical stimulation with an early and/or a late peak of activation, the latencies of which were in the 15-50 ms and 80-170 ms ranges (n = 8), respectively, i.e., compatible with the activation of A delta and C fibers. Interestingly, the cold-specific neurons predominantly responded with a late peak, suggesting these neurons were primarily driven by peripheral C fibers. 7. The intravenous injection of morphine depressed the responses of PB neurons to cold noxious stimuli in a dose-related (1, 3, and 9 mg/kg) and naloxone reversible fashion. The ED50 value was estimated approximately 2 mg/kg. Furthermore, two populations of neurons could be separated according to their morphine sensitivity. 8. It is concluded that PB cold-nonspecific neurons could be involved in affective-emotional, autonomic and neuroendocrine reactions in response to noxious cold events. The PB cold-specific neurons could be, in addition, involved in some thermoregulatory processes.

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Ghosh, Ruby N., and Reza Loloee. "Characterization of Large Area 4H-SiC and 6H-SiC Capacitive Devices at 600 °C." Materials Science Forum 717-720 (May 2012): 1187–89. http://dx.doi.org/10.4028/www.scientific.net/msf.717-720.1187.

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SiC based capacitive devices have the potential to operate in high temperature, chemically corrosive environments provided that the electrical integrity of the gate oxide and metallization can be maintained in these environments. We report on the performance of large area, up to 8 x 10-3 cm2, field-effect capacitive sensors fabricated on both the 4H and 6H polytypes at 600°C. Large area capacitors improve the signal/noise (S/N) ratio which is proportional to the slope of the capacitance-voltage characteristic. At 600 °C we obtain a S/N ~ 20. The device response is independent of polytype, either 4H or 6H-SiC. These results demonstrate the reliability of our field-effect structure, operating as a simple potentiometer at high temperature.

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Dabrowski, Z. T. "Two new species of Cicadulina China (Hemiptera: Euscelidae) from West Africa." Bulletin of Entomological Research 77, no. 1 (March 1987): 53–56. http://dx.doi.org/10.1017/s0007485300011524.

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AbstractTwo new species of Cicadulina, C. ghaurii sp. n. and C. hartmansi sp. n., are described. Both occur over a wide area in Nigeria and Cameroon, and C. ghaurii has been shown to transmit maize streak virus.

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Zhao, Zi Qi, Li Guang Li, Hong Bo Wang, Xian Li Zhao, and Peng Jiang. "Characteristics of Land Surface Temperture (LST) within the Third Ring Road of Shenyang." Applied Mechanics and Materials 737 (March 2015): 913–16. http://dx.doi.org/10.4028/www.scientific.net/amm.737.913.

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Urban heat island (UHI) effect becomes hot spot in the field of urban climatology in the recent decades. Two sampling belts on the Landsat TM/ETM+ image across the center point of main urban area of shenyang were selected along the E-W and S-N directions in order to analyse the characteristics of UHI effect and discuss the relationships between LST and UHI source or sink. The results indicate that for the E-W direction sampling belt, the maximum and minimum LST values were 37.46 °Cand 33.44 °C in 2001 respectively, while those were 34.61 °C and 33.30 °C in 2010. For the S-N direction sampling belt, the corresponding values were 34.53 °C and 29.27 °C in 2001, 34.47 °C and 29.69 °C in 2010. LST fluctuated significantly in the E-W direction sampling belt in 2010 and the difference value was 4.01 °C, so was in the S-N direction sampling belt in 2010 and the difference value was 4.78 °C. LST of the grid was a positive correlation with LST of the UHI source area of grid in 2001 and 2010, so was with that of UHI sink area in 2001 and 2010. LST of grid was a positive correlation with UHI source area.

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Aryanti, Ervina, and Novita Hera. "SIFAT KIMIA TANAH AREA PASCA TAMBANG EMAS: (STUDI KASUS PERTAMBANGAN EMAS TANPA IZIN DI KENEGERIAN KARI KECAMATAN KUANTAN TENGAH, KABUPATEN KUANTAN SINGINGI)." Jurnal Agroteknologi 9, no. 2 (February 28, 2019): 21. http://dx.doi.org/10.24014/ja.v9i2.5681.

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Gold mining activities cause damage the soil. This study aims to know soil chemical properties in post gold mining area (natural forest site, Cyperus kinglia site, open sedoment site and tailing site) after seven years. This research has been conducted from July to December 2017 in Kenegerian Kari gold mining area and central plantation laboratory. The research method used was quantitative descriptive with parameter of observation: pH, kation exchange, N, P, K, C-Organic and C/N ratio. The result showed that N, P, Phosphorus K, KTK content in the low and very low category. KTK, N, P, Phosphorus and K are categorized as low and very low. As well, the organic C content is low except in natural forests. While the C / N ratio category is high for all areas.

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Wang, Ruidong, Xia Yang, Yong Gao, Xiaohong Dang, Yumei Liang, Shuai Qi, Chen Zhao, and Xiaoting Duan. "Decomposition characteristics of long-established Salix psammophila sand barriers in an arid area, Northwestern China." BioResources 16, no. 3 (July 13, 2021): 5947–63. http://dx.doi.org/10.15376/biores.16.3.5947-5963.

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Salix psammophila has been extensively used as a sand barrier material for various desertification control applications. Elucidating the long-term decomposition characteristics and nutrient cycling process of this sand barrier in desert environments is of great importance. In this study, which was conducted for 1 to 9 years, changes in the mass loss percentage and the residual percentage in the decomposition process were explored of S. psammophila sand barriers in arid Northwestern China. In addition, the S. psammophila analysis nutrient elements release rule and its influence on soil properties were evaluated. The results showed that the decomposition process of S. psammophila sand barriers exhibited a “slow-fast” trend. After decomposition time for 9 years, mass decreased remarkably, and the residual percentage was 33.6%. Further, the nutrient release characteristics differed. C, P, and K were in the release state, whereas N was in the enrichment state. The decomposition percentage of the sand barriers was significantly correlated with N, P, K, C/N, C/P, and N/P (p < 0.05). The soil nutrient contents of C, P, and K contents increased 3.43, 2.23, and 2.08 g/kg compared to the initial values, respectively. The soil nutrient contents of N contents decreased 0.19 g/kg.

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ZHAO Tong, 赵彤, 闫浩 YAN Hao, 蒋跃利 JIANG Yueli, 黄懿梅 HUANG Yimei, and 安韶山 AN Shaoshan. "Effects of vegetation types on soil microbial biomass C, N, P on the Loess Hilly Area." Acta Ecologica Sinica 33, no. 18 (2013): 5615–22. http://dx.doi.org/10.5846/stxb201304160723.

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Buikin, A. I., A. B. Verchovsky, and N. A. Migdisova. "N–C–Ar–He Isotopic Systematics of Quenched Tholeiitic Glasses from the Bouvet Triple Junction Area." Geochemistry International 56, no. 13 (December 2018): 1368–83. http://dx.doi.org/10.1134/s0016702918130037.

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Costa, C., E. M. Papatheodorou, N. Monokrousos, and G. P. Stamou. "Spatial Variability of Soil Organic C, Inorganic N and Extractable P in a Mediterranean Grazed Area." Land Degradation & Development 26, no. 2 (December 26, 2012): 103–9. http://dx.doi.org/10.1002/ldr.2188.

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Wan, Jie-Ping, Yi Li, and Yunyun Liu. "Annulation based on 8-aminoquinoline assisted C–H activation: an emerging tool in N-heterocycle construction." Organic Chemistry Frontiers 3, no. 6 (2016): 768–72. http://dx.doi.org/10.1039/c6qo00077k.

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As an important emerging area of 8-aminoquinoline assisted C–H activation, the construction of heterocycles via direct C–H activation and domino reactions involving domino C–H activation/annulation has been highlighted.

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Hasselquist, N. J., M. J. Germino, J. B. Sankey, L. J. Ingram, and N. F. Glenn. "Aeolian nutrient fluxes following wildfire in sagebrush steppe: implications for soil carbon storage." Biogeosciences Discussions 8, no. 4 (August 16, 2011): 8323–49. http://dx.doi.org/10.5194/bgd-8-8323-2011.

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Abstract. Pulses of aeolian transport following fire can profoundly affect the biogeochemical cycling of nutrients in semi-arid and arid ecosystems. Our objective was to determine horizontal nutrient fluxes during an episodic pulse of aeolian transport that occurred following a wildfire in a semi-arid sagebrush steppe ecosystem in southern Idaho, USA. We also examined how temporal trends in nutrient fluxes were affected by changes in particle sizes of eroded mass as well as nutrient concentrations associated with different particle size classes. In the burned area, total carbon (C) and nitrogen (N) fluxes were as high as 235 g C m−1 d−1 and 19 g N m−1 d−1 during the first few months following fire, whereas C and N fluxes were negligible in an adjacent unburned area throughout the study. Temporal variation in C and N fluxes following fire was largely attributable to the redistribution of saltation-sized particles. Total N and organic C concentrations in the soil surface were significantly lower in the burned relative to the unburned area one year after fire. Our results show how an episodic pulse of aeolian transport following fire can affect the spatial distribution of soil C and N, which, in turn, can have important implications for soil C storage. These findings demonstrate how an ecological disturbance can exacerbate a geomorphic process and highlight the need for further research to better understand the role aeolian transport plays in the biogeochemical cycling of C and N in recently burned landscapes.

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Hasselquist, N. J., M. J. Germino, J. B. Sankey, L. J. Ingram, and N. F. Glenn. "Aeolian nutrient fluxes following wildfire in sagebrush steppe: implications for soil carbon storage." Biogeosciences 8, no. 12 (December 14, 2011): 3649–59. http://dx.doi.org/10.5194/bg-8-3649-2011.

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Abstract. Pulses of aeolian transport following fire can profoundly affect the biogeochemical cycling of nutrients in semi-arid and arid ecosystems. Our objective was to determine horizontal nutrient fluxes occurring in the saltation zone during an episodic pulse of aeolian transport that occurred following a wildfire in a semi-arid sagebrush steppe ecosystem in southern Idaho, USA. We also examined how temporal trends in nutrient fluxes were affected by changes in particle sizes of eroded mass as well as nutrient concentrations associated with different particle size classes. In the burned area, total carbon (C) and nitrogen (N) fluxes were as high as 235 g C m−1 d−1 and 19 g N m−1 d−1 during the first few months following fire, whereas C and N fluxes were negligible in an adjacent unburned area throughout the study. Temporal variation in C and N fluxes following fire was largely attributable to the redistribution of saltation-sized particles. Total N and organic C concentrations in the soil surface were significantly lower in the burned relative to the unburned area one year after fire. Our results show how an episodic pulse of aeolian transport following fire can affect the spatial distribution of soil C and N, which, in turn, can have important implications for soil C storage. These findings demonstrate how an ecological disturbance can exacerbate a geomorphic process and highlight the need for further research to better understand the role aeolian transport plays in the biogeochemical cycling of C and N in recently burned landscapes.

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Wang, Xinyou, Quanlin Ma, Hujia Jin, Baoli Fan, Duobin Wang, and Huilong Lin. "Change in Characteristics of Soil Carbon and Nitrogen during the Succession of Nitraria Tangutorum in an Arid Desert Area." Sustainability 11, no. 4 (February 21, 2019): 1146. http://dx.doi.org/10.3390/su11041146.

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The shrub Nitraria tangutorum is distributed widely in arid desert areas, and plays a critical role in the desert–oasis ecosystem. This study quantified varying characteristics of carbon (C) and nitrogen (N) in the soil at four stages—the initial stage (IS), stable stage (SS), degradation stage (DS), and severe degradation stage (SDS)—in a steppe ecosystem in the desert of northwestern China. The results indicated that N. tangutorum experienced both expansion and deterioration as a decline of 50.7% occurred in the available soil water due to agricultural utilization, and the plant community transformed from being shrub-dominated to annual herb-dominated. At soil layer depths between 0–100 cm in the N. tangutorum nebkha dune ecosystem, organic C and total N storage was 1195.84 g/m2 and 115.01 g/m2 during the SDS, respectively, with an increase of 11.13% and 12.59% from the IS. In addition, the storage of C and N in the soil increased during the IS as well as the SS, when most of the C and N were accumulated, and the storage decreased during the DS and SDS, as the N. tangutorum communities declined. At soil layer depths between 0–100 cm in the desert steppe ecosystem, the highest storage levels of C and N were 8465.97 g/m2 and 749.29 g/m2 during the SS, and the lowest were 1076.12 g/m2 and 102.15 g/m2 during the IS, respectively. The changes and accumulation of C and N were greater in the deeper (40–100 cm) layer than in the surface layer of soil (0–40 cm). Lastly, changes in soil organic carbon (SOC) as well as in the total nitrogen (TN) were strongly related to the coverage degree, water content in soil, and the ratio of fine soil particles (silt and clay). To sum up, the intensive development of water resources has vastly reduced the ability of N. tangutorum vegetation to sequester C and N in the desert of Minqin. Efforts to perform ecological restoration and reverse desertification in the Minqin Desert should focus on preventing the unreasonable exploitation of water resources in order to maintain stable N. tangutorum communities.

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Costa, Adilson A., Bruno de O. Dias, Vânia da S. Fraga, Charles C. Santana, and Núbia da Silva. "Carbon and nitrogen stocks in soils under different forms of use in the Cerrado." Revista Brasileira de Engenharia Agrícola e Ambiental 24, no. 8 (August 2020): 528–33. http://dx.doi.org/10.1590/1807-1929/agriambi.v24n8p528-533.

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ABSTRACT The soil is an important component in the biogeochemical cycling of carbon (C) and nitrogen (N). The objective of this study was to evaluate the changes caused by different types of land use on the C and N stocks in areas of Cerrado at different depths: area under conventional tillage, no-tillage, grazing, eucalyptus and area under native vegetation of Cerrado in the municipality of Luis Eduardo Magalhães, BA, Brazil. The highest C content was found for no-tillage area in the surface layer up to 10 cm; however, there was a decrease in its content along the depths. Areas under no-tillage had lower values of C in the surface layer (0-5 cm) and below 20 cm. Among these, C stocks were significantly lower compared to the use of grass and eucalyptus at the depth of up to 40 cm. Considering the depth of 0-60 cm, the highest C stock was found in areas under native vegetation, 62.81 Mg ha-1, followed by the area under cultivation with eucalyptus, 60.70 Mg ha-1. The lowest C stocks were found in areas under conventional use, 44.87 Mg ha-1. Conventional planting reduced N stocks by up to 61 and 56% when compared to areas under native Cerrado vegetation and eucalyptus plantations, respectively, both at a depth of up to 10 cm. Therefore, land use practices such as eucalyptus cultivation and no-tillage contribute to C and N storage over time.

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Nursanti, Ida. "Karakteristik Tanah Area Pasca Penambangan Di Desa Tanjung Pauh." Jurnal Media Pertanian 3, no. 2 (October 22, 2018): 54. http://dx.doi.org/10.33087/jagro.v3i2.73.

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The post-mining soil has poor chemical and physical properties and has a very low fertility rate. The objective of this research is to know the land post-mining characteristics related to planting medium. Implementation of research in Tanjung Pauh Village and soil Laboratory. The research was conducted by survey method and soil laboratory test. Data analysis of the diversity of post-mining soil characteristics is presented in table form and discussed descriptively. Post-mine soil chemical and physical characteristic: soil acidity level in very acidic position pH 4, Al saturation of high criterion equal to 52,86%, iron content 1,51% high criterion, Cation Exchange Capacity of 15,21 cmol (+) kg-1 is low, Saturation saturation of 49.44% is moderate, C-organic is very low that is equal to 0.16%, C / N value of soil 1.46 is very low, N total 0, 11%, P available 9,20 mg kg-1 and K total of soil 0,15 mg kg-1 are each classified as low. The post-mining land has poor physical and chemical characteristics of soil as planting medium. Keywords: soil chemistry, physical soil, Post MineABSTRAKTanah pasca penambangan memiliki sifat kimia dan fisik yang kurang baik serta memiliki tingkat kesuburan yang sangat rendah. Penelitian bertujuan mengetahui karakteristik tanah pasca tambang terkait sebagai media tanam. Pelaksanaan penelitian di Desa Tanjung Pauh dan Laboratorium tanah. Penelitian dilaksanakan dengan metode survey dan uji laboratorium tanah. Analisis data keragaman karakteristik jenis tanah pasca penambangan disajikan dalam bentuk tabel dan dibahas secara deskriptif. Karakteristik kimia dan fisik tanah pasca tambang: tingkat kemasaman tanah berada pada posisi sangat masam pH 4, kejenuhan Al kriteria tinggi sebesar 52,86%, kadar besi 1,51% kriteria tinggi, KTK (Kapasitas Tukar Kation) tanah sebesar 15,21 cmol(+)kg -1 tergolong rendah, Kejenuhan Basa (KB) sebesar 49,44% tergolong sedang, C-organik sangat rendah yaitu sebesar 0,16%, Nilai C/N tanah 1,46 tergolong sangat rendah, N total 0,11%, P tersedia 9,20 mg kg-1 dan K total tanah 0,15 mg kg-1 masing-masing tergolong rendah.Tanah pasca penambangan memiliki karakteristik fisik dan kimia tanah yang kurang baik sebagai media tanam.Kata kunci : Kimia tanah, fisik tanah, Pasca Tambang

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Pietikäinen, Janna, and Hannu Fritze. "Microbial biomass and activity in the humus layer following burning: short-term effects of two different fires." Canadian Journal of Forest Research 23, no. 7 (July 1, 1993): 1275–85. http://dx.doi.org/10.1139/x93-163.

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During a 3-year study, soil microbial biomass C and N, length of the fungal hyphae, soil respiration, and the percent mass loss of needle litter were recorded in coniferous forest soil humus layers following a prescribed burning (PB) treatment or a forest fire simulation (FF) treatment (five plots per treatment). Unburned humus from adjacent plots served as controls (PC and FC, respectively). Prescribed burning was more intensive than the forest fire, and this was reflected in all the measurements taken. The amounts of microbial biomass C and N, length of fungal hyphae, and soil respiration in the PB area did not recover to their controls levels, whereas unchanged microbial biomass N and recovery of the length of the fungal hyphae to control levels were observed in the FF area. The mean microbial C/N ratio was approximately 7 in all the areas, which reflected the C/N ratio of the soil microbial community. Deviation from this mean value, as observed during the first three samplings from the PB area (3, 18, and 35 days after fire treatment), suggested a change in the composition of the microbial community. Of the two treated areas, the decrease in soil respiration (laboratory measurements) was much more pronounced in the PB area. However, when the humus samples from both areas were adjusted to 60% water holding capacity, no differences in respiration capacity were observed. The drier humus, due to higher soil temperatures, of the PB area is a likely explanation for the low soil respiration. Lower soil respiration was not reflected in lower litter decomposition rates of the PB area, since there was a significantly higher needle litter mass loss during the first year in the PB area followed by a decline to the control level during the second year. Consistently higher mass losses were recorded in the FC area than in the FF area.

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KANG, YOUNG SOO, MI HYANG JEONG, SOO JA SHIN, YOUNG HWAN KIM, and CHANG WOO KIM. "SYNTHESIS OF AMPHIPHILIE TEMPO DERIVATIVE AND CHARACTERIZATION OF LANGMUIR MONOLAYERS OF AMPHIPHILIC ALKYL-TEMPOs AT THE AIR/WATER INTERFACE." International Journal of Nanoscience 05, no. 06 (December 2006): 787–93. http://dx.doi.org/10.1142/s0219581x06005169.

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The amphiphilic TEMPO molecules consist of two dissimilar parts. One part is hydrophilic (head) and the rest part is hydrophobic (tail). The derivatives of 4-alkaneamino-2, 2, 6, 6-tetramethyl-1-piperidinyloxy radical ( C n-amino-TEMPO, n = 14, 16, 18, 20, 22) was synthesized with 4-amino-TEMPO and carboxylic acid. The C n-amino-TEMPOs equilibrated at the air/water interface form Langmuir monolayer by classical Langmuir monolayer techniques. The stable monolayers of C 14-22-amino-TEMPOs were characterized by pressure–area isotherms. The features of collapse pressure of C 14-22-amino-TEMPOs were confirmed on alkyl chain length. Limiting area points and take-off area points from surface pressure-MMA isotherms were subjected to the influence of subphase. The monolayer of C 22-amino-TEMPO which has longer alkyl chain was characterized by Brewster Angle Microscopy. So we can confirm phase transition by BAM images as monolayer is expanding at the room temperature.

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Delač, Domina, Paulo Pereira, Igor Bogunović, and Ivica Kisić. "Short-Term Effects of Pile Burn on N Dynamic and N Loss in Mediterranean Croatia." Agronomy 10, no. 9 (September 5, 2020): 1340. http://dx.doi.org/10.3390/agronomy10091340.

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There is a lack of information in the rural Mediterranean area about agricultural pile burning impacts on soil nitrogen (N) dynamic and the N loss. Therefore, this research aims to study the impacts of moderate (MS), and high (HS) severity burn on N transformation and N losses, compared to an unburned (C) during the first year. The experimental plots (10 m2) were established in Croatia (43°58′ N 15°31′ E), in a slope ~18°, with a southwest exposition. Five days after the burn, C treatment had a significantly higher total N (TN) than MS and HS. Generally, the runoff was significantly different between burned and C treatments. Sediment yield, concentrations, and TN loss were significantly higher in MS than in C treatment. The concentrations of ammonium (NH4-N) and nitrate (NO3-N) in the runoff, and their losses were higher in burn treatments than in C treatment. These values were high in the first three months after burn, although the peaks in later periods correspond to extreme rainfall events. Principal component analysis showed that sediment yield was associated with sediment concentration, runoff, and TN loss (Factor 1). In addition, rainfall amount and intensity were inversely related to NH4-N concentration and losses (Factor 2). The NO3-N concentration was positively related to NO3-N losses. Overall, MS treatment had severe effects on N loss and, sediment yield can be used as an indicator of soil degradation after pile burns.

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Asbur, Yenni, Rahmi Dwi Handayani Rambe, Yayuk Purwaningrum, and Dedi Kusbiantoro. "POTENSI BEBERAPA GULMA SEBAGAI TANAMAN PENUTUP TANAH DI AREA TANAMAN KELAPA SAWIT MENGHASILKAN." Jurnal Penelitian Kelapa Sawit 26, no. 3 (December 1, 2018): 113–28. http://dx.doi.org/10.22302/iopri.jur.jpks.v26i3.69.

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Pengelolaan tanaman penutup tanah merupakan salah satu merupakan salah satu teknik konservasi tanah dan air di perkebunan kelapa sawit. Penelitian ini bertujuan untuk mempelajari potensi beberapa gulma sebagai tanaman penutup tanah di perkebunan kelapa sawit menghasilkan. Penelitian dilaksanakan di perkebunan kelapa sawit rakyat umur 20 tahun di Desa Namorambe Kecamatan Namorambe, Kabupaten Deli Serdang, Sumatera Utara dari Maret sampai Juni 2017. Penelitian disusun menggunakan rancangan acak kelompok satu faktor. Empat spesies gulma (N. biserrata, A. gangetica, P. conjugatum, dan A. conyzoides) dijadikan sebagai perlakuan, setiap perlakuan diulang tiga kali. Hasil penelitian menunjukkan bahwa N. biserrata, A. gangetica, P. conjugatum, dan A. conyzoides berpotensi digunakan sebagai tanaman penutup tanah di area kelapa sawit menghasilkan. Keempat spesies tersebut mudah diperbanyak, cepat menutup lahan (8-12 minggu setelah tanam), memproduksi daun dan cabang cukup banyak, dan cukup mengandung unsur hara di dalam jaringan tanamannya. Kandungan N, P, K, dan C organik tertinggi berturut-turut terdapat pada N. biserrata (4,02% N), P. conjugatum (0,31% P), A. gangetica (2,41% K), dan A. conyzoides (37,23% C-organik).

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NOLASCO, JAIRO C., ALEJANDRA CASTRO-CARRANZA, BENJAMÍN IÑIGUEZ, JOSEP PALLARÈS, and MAGALI ESTRADA. "ELECTRICAL PROPERTIES OF P3HT (POLY [3-HEXYLTHIOPHENE])/n-TYPE CRYSTALLINE SILICON (n-c-Si) SOLAR CELLS." International Journal of High Speed Electronics and Systems 20, no. 04 (December 2011): 749–73. http://dx.doi.org/10.1142/s0129156411007033.

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Au / P 3 HT (poly [3-hexylthiophene])/n-type crystalline silicon ( n - c - Si ) solar cells have been fabricated. The Aluminum back contact is obtained by evaporation on silicon substrate. An 80 nm P 3 HT layer thick was spin-coated on silicon substrate followed by thermal annealing. Finally golden contacts are deposited by sputtering. The best characteristics of this flawed solar cell are: V oc =0.47 V , I sc =7.42 mA / cm 2 and an efficiency of 1.29%. The area of this device is 0.07 cm2. In order to get a deep understanding of the electrical properties of the heterojunction, capacitance-voltage and current-voltage-temperature measurements have been made. A compact electrical equivalent circuit has been used to describe the dark current-voltage characteristics. It is based on the combination of two exponential mechanisms, shunt and series resistances and space-charge limited current terms. From the temperature dependence of the extracted parameters we can obtain the limiting conduction mechanism. We found that the polymeric layer limits the current not only at low voltages, through Multi-Tunneling Capture Emission, but also at high voltages, through series resistance and Space-Charge Limited Current. On the other hand, the Silicon wafer limits the current at medium voltages, through the diffusion mechanism. In addition, the model is useful to estimate the open circuit voltage and built in voltage of the solar cell using only dark current voltage measurements.

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Mella, Claudio, Cecilia C. Torres, Gina Pecchi, and Cristian H. Campos. "Mesoporous Palladium N,N’-Bis(3-Allylsalicylidene)o-Phenylenediamine-Methyl Acrylate Resins as Heterogeneous Catalysts for the Heck Coupling Reaction." Materials 12, no. 16 (August 16, 2019): 2612. http://dx.doi.org/10.3390/ma12162612.

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Palladium N,N’-bis(3-allylsalicylidene)o-phenylenediamine complex (PdAS) immobilized onto mesoporous polymeric methyl acrylate (MA) based resins (PdAS(x)-MA, x = 1, 2, 5, or 10 wt.%) were successfully prepared as heterogeneous catalysts for the Heck reaction. The catalysts were synthesized via radical suspension polymerization using PdAS as a metal chelate monomer, divinylbenzene and MA as co-monomers. The effect of the PdAS(x) content on the physicochemical properties of the resins is also reported. The catalysts were characterized by using a range of analytical techniques. The large surface area (>580 m2·g−1) and thermal stability (up to 250 °C) of the PdAS(x)-MA materials allows their application as catalysts in the C–C coupling reaction between iodobenzene and MA in the presence of trimethylamine at 120 °C using DMF as the solvent. The PdAS(10)-MA catalyst exhibited the highest catalytic performance with no significant catalytic loss being observed after five reuses, thereby indicating excellent catalyst stability in the reaction medium.

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Huo, Lili, Baocang Liu, Geng Zhang, Rui Si, Jian Liu, and Jun Zhang. "2D Layered non-precious metal mesoporous electrocatalysts for enhanced oxygen reduction reaction." Journal of Materials Chemistry A 5, no. 10 (2017): 4868–78. http://dx.doi.org/10.1039/c6ta10261a.

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2D Layered meso-M/N-C/N-G nanocomposites with high specific surface area, homogeneous distribution of ultra-small M-N-C nanoparticles less than 5 nm, and mesopores with a size of ∼3.6 nm exhibit excellent electrocatalytic activity toward oxygen reduction reaction (ORR) in acidic and alkaline media.

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Balister, Paul, Béla Bollobás, Amites Sarkar, and Mark Walters. "A critical constant for the k nearest-neighbour model." Advances in Applied Probability 41, no. 1 (March 2009): 1–12. http://dx.doi.org/10.1239/aap/1240319574.

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Let 𝒫 be a Poisson process of intensity 1 in a square Sn of area n. For a fixed integer k, join every point of 𝒫 to its k nearest neighbours, creating an undirected random geometric graph Gn,k. We prove that there exists a critical constant ccrit such that, for c < ccrit, Gn,⌊c log n⌋ is disconnected with probability tending to 1 as n → ∞ and, for c > ccrit, Gn,⌊c log n⌋ is connected with probability tending to 1 as n → ∞. This answers a question posed in Balister et al. (2005).

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Li, Wanpeng, Jian Mao, and Jie Feng. "Aluminium grain refinement by Ti(C, N) nanoparticles additions: principles, advantages and drawbacks." Metallurgical Research & Technology 116, no. 2 (2019): 212. http://dx.doi.org/10.1051/metal/2018083.

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Ti(C, N) is a ceramic particle with high melting point, high hardness, high thermal and chemical stability. And incorporated Ti(C, N) particles is demonstrated to refine the grain and improve the mechanical properties of aluminium and its alloys. In this article, effects of the addition amount of Ti(C, N) particles on grain refinement and mechanical properties of aluminium alloy are reviewed, and the mechanisms of aluminium alloy refined by Ti(C, N) are described. In addition, due to the poor wettability of Ti(C, N) nanoparticles with aluminium alloy melt and the large specific surface area of Ti(C, N) nanoparticles, the Ti(C, N) nanoparticles are prone to aggregate in molten aluminium, which severely limits the application of Ti(C, N) in aluminium alloy. And effective approaches to improving the wettability of Ti(C, N) nanoparticles refine aluminium alloys are provided.

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Wu, Tianxing, Haimin Zhang, Xian Zhang, Yunxia Zhang, Huijun Zhao, and Guozhong Wang. "A low-cost cementite (Fe3C) nanocrystal@N-doped graphitic carbon electrocatalyst for efficient oxygen reduction." Physical Chemistry Chemical Physics 17, no. 41 (2015): 27527–33. http://dx.doi.org/10.1039/c5cp04252f.

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A core–shell structure Fe₃C nanocrystal@N-doped graphitic carbon (Fe₃C@NGC) nanocomposite was successfully fabricated, and used as an electrocatalyst with large surface area, exhibiting great potential for oxygen reduction reaction (ORR).

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Gurgel, Antonio Leandro Chaves, Gelson dos Santos Difante, Alexandre Romeiro de Araujo, Denise Baptaglin Montagner, Valeria Pacheco Batista Euclides, and Manoel Gustavo Paranhos da Silva. "Carbon and Nitrogen Stocks and Soil Quality in an Area Cultivated with Guinea Grass under the Residual Effect of Nitrogen Doses." Sustainability 12, no. 22 (November 11, 2020): 9381. http://dx.doi.org/10.3390/su12229381.

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This study examines the residual effect of nitrogen (N) doses on the carbon (C) and N stocks and on soil quality in an area cultivated with guinea grass. The pastures received three annual doses of N (100, 200 and 300 kg ha−1) from 2015 to 2017. In 2018, N fertilization was not applied so the residual effect of the nutrient could be characterized. Soil chemical attributes, C and N stocks, density and penetration resistance and root system characteristics were evaluated at different depths. No difference was observed between the N doses for soil density, which averaged 1.22 and 1.25 g cm−3 under and between the tussocks of guinea grass, respectively. Penetration resistance was affected by the N doses post-grazing, with the highest value (1.9 MPa) observed in pastures that received 300 kg ha−1 of N for three consecutive years. Root dry mass was not affected by the N doses. There was no effect of N doses on the average (19.7 mg ha−1) or total (134.3 mg ha−1) C stock in the soil. The total N stock did not change (11.3 mg ha−1) in response to the N doses; however, the average N stock was higher in the soil cultivated with guinea grass under the N dose of 300 kg ha−1 (1.7 mg ha−1). The N doses had little interference with the soil chemical and physical aspects. Regardless of the dose, high C and N stocks were observed in the soil cultivated with guinea grass. Therefore, when properly managed, intensive pasture-based animal production systems become important allies of the environment.

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Li, Haicheng, Linlin Zang, Fengtong Shen, Libin Wang, Liguo Sun, and Fulong Yuan. "Tubular g-C3N4/carbon framework for high-efficiency photocatalytic degradation of methylene blue." RSC Advances 11, no. 30 (2021): 18519–24. http://dx.doi.org/10.1039/d1ra02918e.

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Tubular g-C₃N₄ grown on a carbon framework increased the surface area of bulk g-C₃N₄, enhanced the absorption of visible light and promoted the photocatalytic performance.

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Muñoz-Molina, José María, Tomás R. Belderrain, and Pedro J. Pérez. "Recent Advances in Copper-Catalyzed Radical C–H Bond Activation Using N–F Reagents." Synthesis 53, no. 01 (August 25, 2020): 51–64. http://dx.doi.org/10.1055/s-0040-1707234.

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This Short Review is aimed at giving an update in the area of copper-catalyzed C–H functionalization involving nitrogen-centered radicals generated from substrates containing N–F bonds. These processes include intermolecular Csp3–H bond functionalization, remote Csp3–H bond functionalization via intramolecular hydrogen atom transfer (HAT), and Csp2–H bond functionalization, which might be of potential use in industrial applications in the future.1 Introduction2 Intermolecular Csp3–H Functionalization3 Remote Csp3–H Functionalization4 Csp2–H Functionalization5 Conclusion

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Dománková, Mária, Katarína Bártová, and Peter Pastier. "Aging Precipitation Behaviour of Cr-Mn-N Austenitic Stainless Steels." Materials Science Forum 891 (March 2017): 155–60. http://dx.doi.org/10.4028/www.scientific.net/msf.891.155.

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This work is focused on the austenite decomposition in Cr-Mn-N austenitic stainless steels. The experimental steels was solution heat treated (1100°C/30 min. followed by water quenching) and then annealed in the temperature range from 650 to 900°C for holding time 5 min. to 100 hours for the study of precipitation. The precipitation behaviour during isothermal aging was investigated using light optical microscopy, transmission electron microscopy, selected area diffraction and energy-dispersive X-ray spectroscopy. The results show that the phase composition of the precipitates depends on the chemical composition of the experimental steel. The critical temperature of precipitation is 825°C with the corresponding time 100 s.

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Koralay, Demet Banu. "Organic geochemical and isotopic (C and N) characterization of carbonaceous rocks of the Denizli Area, Western Turkey." Journal of Petroleum Science and Engineering 116 (April 2014): 90–102. http://dx.doi.org/10.1016/j.petrol.2014.02.020.

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Shubina, K. Yu, A. M. Mizerov, S. N. Timoshnev, D. V. Mokhov, E. V. Nikitina, I. Kim, and A. D. Bouravleuv. "Selective area epitaxy of n+-GaN layers on SiO2 patterned GaN/c-Al2O3 templates by PA MBE." Journal of Physics: Conference Series 1410 (December 2019): 012014. http://dx.doi.org/10.1088/1742-6596/1410/1/012014.

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Ghosh, Ruby N., Reza Loloee, Tamara Isaacs-Smith, and John R. Williams. "High Temperature Reliability of SiC n-MOS Devices up to 630 °C." Materials Science Forum 527-529 (October 2006): 1039–42. http://dx.doi.org/10.4028/www.scientific.net/msf.527-529.1039.

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SiC based field-effect devices are attractive for electronic and sensing applications above 250 °C. At these temperatures the reliability of the insulating dielectric in metal-oxidesemiconductor (MOS) structures becomes an important parameter in terms of long-term device performance. We report on the reliability of n-MOS SiC capacitors following thermal stress cycling in the 330 to 630 °C range. As the primary mode of oxide breakdown under these conditions is believed to be due to electron injection from the substrate, the gate leakage current was measured as a function of temperature. The gate dielectric was grown using dry oxidation with a post oxidation NO passivation anneal. For large area, 1 mm diameter, 6H-SiC capacitors we obtain current densities as low as 5nA/cm2 at 630 °C. In addition, gate leakage measurements from arrays of 300 to 1000 2m diameter devices fabricated on different 1cm2 6H-SiC substrates are presented. These are encouraging results for the long-term reliability of SiC field-effect sensors.

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Journal articles on the topic 'Zebulon area, N.C'

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