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Organic carbon fluxes from the upper Yangtze basin: an example of the Longchuanjiang River, china

HYDROLOGIcAL PROcESSES 2012年第11期26卷 1604-1616页

作者： Lu, X. X. Li, Siyue He, Min Zhou, Yue Li, Li Ziegler, Alan D. Natl Univ Singapore Dept Geog Singapore 117570 Singapore Yunnan Univ Finance & Econ Global Change & Watershed Management Ctr Kunming 650221 Peoples R China

To investigate the effects of anthropogenic activity, namely, land use change and reservoir construction, on particulate organic carbon (POc) transport, we collected monthly water samples during September 2007 to August 2009 from the Longchuanjiang River to understand seasonal variations in the concentrations of organic carbon species and their sources and the yield of organic and inorganic carbon from the catchment in the Upper Yangtze basin. The contents of riverine POc, total organic carbon and total suspended sediment (TSS) changed synchronously with water discharge, whereas the contents of dissolved organic carbon had a small variation. The POc concentration in the suspended sediment decreased non-linearly with increasing TSS concentration. Higher molar c/N ratio of particulate organic matter (average 77) revealed that POc was dominated by terrestrially derived organic matter in the high flows and urban wastewaters in the low flows. The TSS transported by this river was 2.7?x?105?t/yr in 2008. The specific fluxes of total organic carbon and dissolved inorganic carbon (DIc) were 5.6 and 6?t/km2/yr, respectively, with more than 90% in the high flow period. A high carbon yield in the catchment of the upper Yangtze was due to human-induced land use alterations and urban wastes. consistent with most rivers in the monsoon climate regions, the dissolved organic carbonPOc ratio of the export flux was low (0.41). Twenty-two percent (0.9?t/km2/yr) of POc out of 4?t/km2/yr was from autochthonous production and 78% (3.1?t/km2/yr) from allochthonous production. The annual sediment load and hence the organic carbon flux have been affected by environmental alterations of physical, chemical and hydrological conditions in the past 50?years, demonstrating the impacts of human disturbances on the global and local carbon cycling. Finally, we addressed that organic carbon flux should be reassessed using adequate samples (i.e. at least two times in low-flow month, four times in high

关键词： dissolved organic carbon particulate organic carbon c N ratio water discharge sediment loads Longchuanjiang Yangtze River

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Pressure-induced structural phase transition in transition metal carbides TMc (TM = Ru, Rh, Pd, Os, Ir, Pt): a DFT study

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PHILOSOPHIcAL MAGAZINE 2018年第7期98卷 541-559页

作者： Manikandan, M. Rajeswarapalanichamy, R. Iyakutti, K. NMSSVN Coll Dept Phys Madurai Tamil Nadu India SRM Univ Dept Phys & Nanotechnol Chennai Tamil Nadu India

First-principles calculations based on density functional theory was performed to analyse the structural stability of transition metal carbides TMc (TM=Ru, Rh, Pd, Os, Ir, Pt). It is observed that zinc-blende phase is the most stable one for these carbides. Pressure-induced structural phase transition from zinc blende to NiAs phase is predicted at the pressures of 248.5 GPa, 127 GPa and 142 GPa for Osc, Irc and Ptc, respectively. The electronic structure reveals that Ruc exhibits a semiconducting behaviour with an energy gap of 0.7056eV. The high bulk modulus values of these carbides indicate that these metal carbides are super hard materials. The high B/G value predicts that the carbides are ductile in their most stable phase.

关键词： c Density functional theory D crystal structure D Phase transition D Electronic structure D Mechanical properties

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Achievement of high-purity carbon nanofibres via peeling process

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MIcRO & NANO LETTERS 2020年第14期15卷 1038-1040页

作者： Zhao, Xianglong chen, Bin Shandong Jianzhu Univ Sch Sci Jinan 250101 Peoples R China Chinese Acad Sci Inst Solid State Phys Key Lab Mat Phys Hefei 230031 Peoples R China Chinese Acad Sci Inst Solid State Phys Anhui Key Lab Nanomat & Nanotechnol Hefei 230031 Peoples R China

The authors report a facile approach to high-purity carbon nanofibres (cNFs), by performing chemical vapour deposition on aluminium foils loaded with metal (nickel or cobalt) nitrates, and then peeling the as-grown cNFs off. The growth of cNFs was catalysed by metal nanoparticles and followed bottom-growth mechanism, and the high-purity cNFs were achieved due to detachment of cNFs from their underlying metal nanoparticles during the peeling process. This approach may pave a new way for the controlled and scalable synthesis of high-purity carbon materials.

关键词： chemical vapour deposition carbon fibres nanoparticles nanofibres adhesion nanofabrication metal nanoparticles peeling process high-purity carbon nanofibres chemical vapour deposition aluminium foils bottom-growth mechanism c

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Electrochemical capacitors utilizing low surface area carbon fiber

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IEEE AEROSPAcE AND ELEcTRONIc SYSTEMS MAGAZINE 1997年第7期12卷 27-30页

作者： Lipka, SM Department of Occan Engineegine Florida Atlantic University Boca Raton FL USA

The performance of electrochemical capacitors containing different commercial carbon fibers is reviewed. High specific capacitance (ca. 300 F/g) is obtained with low surface area carbon fiber (< 1 m(2)/g) using a proprietary activation process. capacitance is primarily achieved through pseudocapacitance resulting from surface functional groups. The performance of these devices is dependent on the type of carbon fiber, its carbon content, aspect ratio and microstructure. These devices can achieve high cycle life (ca. 100k) without significant loss in capacitance.

关键词： capacitance carbon fibres electrochemical electrodes electrolytic capacitors life testing c activation process aspect ratio carbon fibers cycle life double-layer capacitors electrochemical capacitors microstructure pseudocapacitance specific capacitance specific capacitance capacitance electric double-layer capacitor carbon fiber Life testing electrochemical capacitors Electrolytic capacitors cycle life ASPEcT RATIO Electrochemical electrodes Microstructure

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Graphene-based THz modulator analysed by equivalent circuit model

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MIcRO & NANO LETTERS 2016年第8期11卷 439-442页

作者： Xiao, Binggang chen, Jing Xie, Zhiyi Xiao, Sanshui Ji Liang Univ China Coll Informat Engn Hangzhou 310018 Zhejiang Peoples R China Tech Univ Denmark Dept Photon Engn DK-2800 Lyngby Denmark

A terahertz (THz) modulator based on graphene is proposed and analysed by use of equivalent transmission line of a homogeneous medium and the local anisotropic model of the graphene conductivity. The result calculated by the equivalent circuit is consistent with that obtained by Fresnel transfer matrices. For the modulator proposed here, when the frequency of carrier wave is 0.6 THz, the theoretical analysis indicates that the modulation bandwidth is 55.5 kHz and the modulation depth is 81.3% for voltage change from 0 to 50 V.

关键词： terahertz wave devices equivalent circuits modulators graphene graphene based THz modulator equivalent circuit model equivalent transmission line graphene conductivity Fresnel transfer matrices bandwidth 55 5 kHz c

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characterisation of a carbon nanotube random network conjugated by semiconductor nanoparticles with defined nanometre-scaled gaps

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MIcRO & NANO LETTERS 2012年第8期7卷 753-756页

作者： Kumagai, S. Okamoto, N. Kobayashi, M. Yamashita, I. Toyota Technol Inst Dept Adv Sci & Technol Nagoya Aichi 468 Japan Nara Inst Sci & Technol Grad Sch Mat Sci Nara Japan Japanese Fdn Canc Res Inst Canc Tokyo 170 Japan

Utilising a biological material, a novel cNT nanostructure conjugated by semiconductor nanoparticles (NPs) was synthesised intended for electronics devices with unprecedented properties. A peptide aptamer that has an affinity for carbonaceous materials was fused to a cage-shaped protein (LiDps) to be displayed on its outer surface. As a potential coulomb island, semiconductor NPs were synthesised within the cavity of engineered protein (NHBP-LiDps). By the affinity of the peptide aptamer, the NHBP-LiDps proteins accommodating semiconductor NPs were adhered to surround the cNTs with nanometre-scaled gaps defined by the thickness of the protein cage. Using a dielectrophoresis assembly, the random network of cNTs conjugated by the NHBP-LiDps with NP cores was formed between a pair of electrodes. Electronic characterisation was performed on the random network of cNTs conjugated with NPs. coulomb blockade was observed. When cNTs were dispatched between a pair of electrodes, ohmic characteristics were observed. Apparently, the direct contact between cNTs was avoided by the NHBP-LiDps proteins surrounding the cNTs. The results are the first steps towards revealing unique electronic properties of these cNT conjugates.

关键词： Low-dimensional structures: growth, structure and nonelectronic properties proteins nanoparticles biological material Structure of solid clusters, nanoparticles, nanotubes and nanostructured materials c electrophoresis coulomb blockade carbonaceous materials electrodes peptide aptamer nanometre scaled gap Electrochemistry and electrophoresis ohmic contacts Electrical properties of fullerenes and related materials (thin films/low-dimensional structures) cage shaped protein Electrical properties of metal-nonmetal contacts ohmic characteristics carbon nanotube random network Preparation of fullerenes and fullerene-related materials, intercalation compounds, and diamond NHBP-LiDps proteins carbon nanotubes coulomb island dielectrophoresis assembly quantum tunnelling nanofabrication semiconductor nanoparticles cNT nanostructure Methods of nanofabrication and processing

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carbon nanotube photothermionics: Toward laser-pointer-driven cathodes for simple free-electron devices and systems

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MRS BULLETIN 2017年第7期42卷 500-504页

作者： Nojeh, Alireza Univ British Columbia Quantum Matter Inst Dept Elect & Comp Engn Vancouver BC Canada

Light-induced generation of free electrons is of interest for a wide variety of vacuum electronic devices and systems. The properties of nanomaterials, stemming from their geometry and the strong manifestation of quantum phenomena in them, have opened up new avenues for developing new cathodes and exploring and exploiting electron emission. This article presents the heat trap effect-efficient localized heating of carbon nanotube arrays using light, leading to electron emission through the thermionic mechanism. This process requires unexpectedly modest amounts of optical power-available from sources such as handheld lasers-and dramatically simplifies the electron emitter. Potential applications, including thermionic and thermoelectric conversion for solar-energy harvesting and simple electron-beam systems, are also highlighted.

关键词： c nanostructure laser photoemission thermionic emission

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Effects of surface charging treatment on outer and inner surfaces of a nanoporous carbon

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JOURNAL OF MATERIALS RESEARcH 2009年第8期24卷 2471-2475页

作者： Lu, Weiyi Han, Aijie Kim, Taewan Lim, Hyuck Qiao, Yu Univ Calif San Diego Dept Struct Engn La Jolla CA 92093 USA Univ Calif San Diego Program Mat Sci & Engn La Jolla CA 92093 USA Univ Texas Pan Amer Dept Chem Edinburg TX 78539 USA

As the outer surface of a nanoporous carbon is treated with 16-mercaptohexadecanoic acid, the carbon particles can form a stable suspension in water. When the water phase is compressed, the liquid infiltration behavior in the nanopores becomes significantly different from that of untreated material, suggesting that the inner surface is also modified. After the treatment, the infiltration pressure does not decrease. Therefore, the chain configurations at the inner and outer surfaces must be different, which explains the variations in infiltration pressure and volume.

关键词： c Infiltration (assembly) Surface reaction

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High-spin organic molecular materials

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cURRENT OPINION IN SOLID STATE & MATERIALS ScIENcE 1997年第4期2卷 446-450页

作者： Matsuda, K Iwamura, H Institute for Fundamental Research of Organic Chemistry Kyushu University Hakozaki Higashi-ku Fukuoka 812-81 Japan

High-spin organic molecular materials are recent subjects of active studies. In diradicals and radical pairs, the ground states are usually singlet due to the overlap of the orbitals containing the unpaired electrons. When the singly occupied orbitals are orthogonal to each other, triplet states become ground states. Thanks to the promotion of our understanding of how to stabilize the triple relative to the singlet, a number of examples of purely organic assemblies of free radicals and oligo/polyradicals have been accumulated, in which more than two electron spins are aligned in parallel. Approaches toward high T-c and tunable organic molecule-based magnets are in steady progress.

关键词： AH alternant hydrocarbon J exchange coupling parameter: + and − signs correspond to ferro- and antiferromagnetic interactions, respectively. T c critical temperature TME tetramethyleneethane TMM trimethylenemethane

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Printable high-speed thin-film transistor on flexible substrate using carbon nanotube solution

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MIcRO & NANO LETTERS 2007年第4期2卷 96-98页

作者： Han, X. Janzen, D. c. Vaillancourt, J. Lu, X. Brewer Sci Inc Rolla MO 65401 USA Univ Massachusetts Lowell Dept Elect & Comp Engn Lowell MA 01854 USA

A printable high-speed thin-film transistor (TFT) fabricated on a regular plastic transparency film is proposed. The carrier transport layer of the TFT is an ultrapure carbon nanotube (cNT) thin film of high density (> 1000 cNTs per mu m(2)) formed at room temperature by dispensing a tiny droplet of an electronic-grade cNT solution, which does not contain any surfactant. This cNT TFT exhibited a high-modulation speed of 312 MHz and a large current-carrying capacity beyond 20 mA. A unique ink-jet printing compatible process demonstrated herein would enable mass production of large-area electronic circuits on any virtually desired flexible substrate at low cost and high throughput.

关键词： current-carrying capacity nanotube devices Other field effect devices printable high-speed thin-film transistor thin film transistors c ink jet printers nanotube ultrapure carbon nanotube thin film flexible substrate Fullerene, nanotube and related devices printing plastic transparency film electronic-grade solution carrier transport layer ink-jet printing large-area electronic circuits carbon nanotubes frequency 312 MHz room temperature

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