Although most studies have indicated that biochar can boost rice (Oryza sativa) growth, the material may also suppress it, depending on ratios of carbon (c) to nitrogen (N) and available N to available phosphorous (P)...
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Although most studies have indicated that biochar can boost rice (Oryza sativa) growth, the material may also suppress it, depending on ratios of carbon (c) to nitrogen (N) and available N to available phosphorous (P). The current study sought to examine the impacts of biochar on rice growth and to identify underlying mechanisms. A pot experiment was conducted using two soils of high (3.05%) and low (0.54%) organiccarbon (Oc) content, mixed with 0, 1.5, 3, 6, and 12% biochar and planted with rice. Rice growth components, five rice tissue nutrients, and nine soil properties were measured. The results showed that the response of rice growth to biochar rates could be described using an exponential-growth function in high-Oc soil but an inverted U-shaped curve in low-Oc soil. In high-Oc soil, the 12% biochar rate led to the greatest total biomass, increased by 47%, whereas in low-Oc soil, the 3 and 6% rates exhibited the highest total biomass, increased by 44%, compared to the no-biochar added soils. Biochar elevated the c:N ratio from 11.5 to 39.1, with an optimal range of 20-30 corresponding to the highest rice growth. Biochar declined the ratio of NH4-N to Mehlich-1 P, causing N deficiency. In brief, high biochar rates may suppress rice growth when the soil c:N ratio exceeds 30. The applied biochar rate should be considered based on soil properties typically Oc and N content to obtain the c:N ratio between 20 and 30 for optimal rice growth.
We consider the stochastic queue core problem on a tree network. Our aim is to find an optimal path on a tree network subject to the average travel time of particles moving along the tree for service given by a server...
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We consider the stochastic queue core problem on a tree network. Our aim is to find an optimal path on a tree network subject to the average travel time of particles moving along the tree for service given by a server traversing along the optimal path. We assume that particles originating at a node on a tree network request their demands for service randomly and the server is modeled first by an M/M/1 and then by an M/G/1 queue using the FIFO discipline. We consider that all paths along which the particles travel are modeled with an M/G/c/c state-dependent queue with the particles being independent of each other having demands according to the Poisson distribution. Two algorithms are developed for computing the optimal path on a tree network along with the M/M/1 and the M/G/1 queues. The computational complexity of the algorithms and illustrative numerical results obtained by implementations of the algorithms in MATLAB software environment are given.
A new surface micromachining way of ultrashort plus laser for c/Siccomposites with high quality and efficiency was demonstrated, including picosecond and femtosecond laser. Surface morphologies, element content and b...
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A new surface micromachining way of ultrashort plus laser for c/Siccomposites with high quality and efficiency was demonstrated, including picosecond and femtosecond laser. Surface morphologies, element content and bonding states of c/Siccomposites were analysed in detail after machined by picosecond and femtosecond laser power respectively. For femtosecond laser machining, the amount of nanoparticles increased with increasing laser power. At 20 and 50mW, Si-c, c-c and Si-O bonds existed in nanoparticles, while Si-c bonds disappeared at 70mW. For picosecond laser machining, cauliflower-like particles and periodic ripple with certain depth were formed distinctly. Furthermore, thermal ablation phenomenon occurred, and only Si-O bonds existed in particles due to the oxidation of the carbon fibres and Sic matrix. The results showed that femtosecond laser with low power was more suitable to the surface machining due to better machining quality and less machining damage compared with high power picosecond laser.
Despite its maturity and popularity, the c programming language still lacks tool support for reliably performing even simple refactoring, browsing, or analysis operations. This is primarily due to identifier scope com...
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Despite its maturity and popularity, the c programming language still lacks tool support for reliably performing even simple refactoring, browsing, or analysis operations. This is primarily due to identifier scope complications introduced by the c preprocessor. The cScout refactoring browser analyses complete program families by tagging the original identifiers with their precise location and classifying them into equivalence classes orthogonal to the c language's namespace and scope extents. A web-based user interface provides programmers with an intuitive source code analysis and navigation front-end, while an SQL-based back-end allows more complex source code analysis and manipulation. cScout has been successfully applied to many medium and large-sized proprietary and open-source projects identifying thousands of modest refactoring opportunities. (c) 2009 Elsevier B.V. All rights reserved.
An improved high-solid-loading slurry impregnation process was developed to introduce HfB2 particles into a low-density c/c preform efficiently, and precursor infiltration and pyrolysis process was used for densificat...
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An improved high-solid-loading slurry impregnation process was developed to introduce HfB2 particles into a low-density c/c preform efficiently, and precursor infiltration and pyrolysis process was used for densification to obtain a c/c-HfB2-Siccomposite. The microstructure characterization revealed that HfB2 particles uniformly filled the pores in the c/c preform, and Sic well densified the interstices between HfB2 particles and the small pores in the carbon fiber bundles. After being tested, the c/c-HfB2-Siccomposite had a density of 4.07 g/cm3 and a bending strength of 344.8 MPa, and exhibited a non-brittle fracture behavior. After ablation with oxyacetylene flame at 2500 for 120 s, the mass ablation rate and linear ablation rate of the c/c-HfB2-Siccomposite were 0.5 mg/s and 0.415 mu m/s, respectively. The good ablation performance is attributed to the hindering effect of the HfO2 scale on oxygen diffusion at high temperature.
Metastasis is the primary cause of death in cancer patients. cXcR4/cXcL12 chemokine axis provides directional cues for breast cancer cells to metastasize to specific organs. Despite their potential clinical importance...
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Metastasis is the primary cause of death in cancer patients. cXcR4/cXcL12 chemokine axis provides directional cues for breast cancer cells to metastasize to specific organs. Despite their potential clinical importance, how cXcR4 expression in breast cancer cells is regulated at the molecular level is not well understood. We identified an isoform of c/EBP, liver-enriched inhibitory protein (LIP), as a previously unrecognized transcriptional regulator of cXcR4 in breast cancer cells. LIP up-regulated the transcription of cXcR4 through direct interaction with the cXcR4 promoter. The increase in cXcR4 mRNA was paralleled by an increased cell surface expression of the cXcR4, which in turn promoted cXcR4-mediated breast cancer cell migration. A significant positive correlation between LIP and cXcR4 expression was observed in stage III and IV human breast carcinoma specimens. Neuregulin 1 (or NRG1, hereafter referred to as heregulin) increased cXcR4 expression in breast cancer cells, and this coincided with increased LIP binding on the cXcR4 promoter. These findings may have important implications for understanding the molecular basis of cXcR4-mediated breast cancer cell metastasis and could potentially allow us to develop novel strategies to reduce morbidity and mortality in patients with metastatic breast cancer.
We describe a production quality implementation of Scheme. Its design, and therefore the program, is based around objects although it is written in c, a language not specifically intended for object-oriented programmi...
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We describe a production quality implementation of Scheme. Its design, and therefore the program, is based around objects although it is written in c, a language not specifically intended for object-oriented programming. This was a fortuitous choice as it allowed us to recover from a design mistake that was not discovered until implementation time. Moreover, as we designed the program around objects and were not constrained by a strict object-oriented notation, this created a program that others have found easy to understand, extend and tune for improved performance.
The carbonaceous residue (coke) formed on HZSM-5 during the conversion of methanol to gasoline was studied by 13 c n.m.r. spectroscopy using cross-polarization and magic angle spinning and by e.p.r. spectroscopy. Meas...
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The carbonaceous residue (coke) formed on HZSM-5 during the conversion of methanol to gasoline was studied by 13 c n.m.r. spectroscopy using cross-polarization and magic angle spinning and by e.p.r. spectroscopy. Measurements were made on samples with different coke contents and on samples from which some external coke had been removed by treatment with an oxygen plasma. It was found that the amount of carbon visible by n.m.r. differed from that expected from the measured coke contents and that the ratio of these amounts varied with the degree of coking. We concluded that the n.m.r.-visible carbon was most probably composed of methyl-substituted polycyclic aromatic hydrocarbons, the degree of methyl substitution and ring condensation changing with the coke content. It was inferred that these methyl-substituted polycyclic aromatics were present in the channels of the zeolite whereas the coke invisible to n.m.r. could be highly condensed polycyclic aromatics or “graphitic” structures on the external surfaces of the zeolite crystals. It appears that initial coke formation is internal and that external coke forms at latter stages in the deactivation process.
Many existing systems are written in c and are not re-entrant or thread safe. Sometimes these systems are required in a context for which they were not first designed, possibly meaning they now need to be re-entrant. ...
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Many existing systems are written in c and are not re-entrant or thread safe. Sometimes these systems are required in a context for which they were not first designed, possibly meaning they now need to be re-entrant. This article introduces a program that filters c source code, modifying shared resources (the global variables) to make the code re-entrant: 'virtualizing' the code. The code is then compiled as normal. This approach allows programmatic virtualization with little cost at runtime. copyright (c) 2007 John Wiley & Sons, Ltd.
The kinematic viscosity of Fe-Mn-c melts is measured with Mn contents of 5.0, 7.5, 10.0, 12.0, 15.0, 17.5, 20.0, and 25.0 wt % and ccontents of 0.4 to 2.2 wt %. The kinematic viscosity is measured using damped torsio...
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The kinematic viscosity of Fe-Mn-c melts is measured with Mn contents of 5.0, 7.5, 10.0, 12.0, 15.0, 17.5, 20.0, and 25.0 wt % and ccontents of 0.4 to 2.2 wt %. The kinematic viscosity is measured using damped torsional vibrations of a crucible with a melt upon the heating and subsequent cooling of the samples. The temperatures at which the characteristics of the viscous flow change and the liquid-liquid structural transition occurs in Fe-Mn-c melts are determined using the results from measuring the kinematic viscosity.
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