39,419 research outputs found

    Floral syndrome and breeding system of Senna (Cassia) corymbosa

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    Senna (Cassia) corymbosa is an ornamental plant with asymmetric flower in which petals and stamens are also involved in floral asymmetry. The pollen number of abaxial lateral stamen (AL), abaxial median stamen (AM) and middle stamen (MI) are descended in sequence. In field, the insects of visiting flowers are available and pollinators are essential to the pollination success of S. corymbosa. Bombidae was presumably the effective pollinators by buzzing pollination and wasp may be the potential pollinators. Pollen number and germination rate per type of stamen experiments supported the hypothesis of “division-of-labour” among stamens by Darwin. Both AL, AM and MI may afford food to visiting insects, while long stamens (including AL and AM) function as the “pollinating” stamens and the brownish yellow is presumably the effective color attractants to pollinators.Key words: Senna, pollen, pollination, breeding system

    Photoelectrocatalytic degradation of humic acid in aqueous solution using a Ti/TiO?mesh photoelectrode

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    Author name used in this publication: X. Z. LiAuthor name used in this publication: F. B. Li2001-2002 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

    Enhancement of photocatalytic oxidation of humic acid in Tio?suspensions by increasing cation strength

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    Author name used in this publication: X. Z. Li2001-2002 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

    Trace metal distribution in sediments of the Pearl River Estuary and the surrounding coastal area, South China

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    Author name used in this publication: Carman C. M. IpAuthor name used in this publication: Onyx W. H. Wai2006-2007 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

    A possible method for non-Hermitian and non-PTPT-symmetric Hamiltonian systems

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    A possible method to investigate non-Hermitian Hamiltonians is suggested through finding a Hermitian operator η+\eta_+ and defining the annihilation and creation operators to be η+\eta_+-pseudo-Hermitian adjoint to each other. The operator η+\eta_+ represents the η+\eta_+-pseudo-Hermiticity of Hamiltonians. As an example, a non-Hermitian and non-PTPT-symmetric Hamiltonian with imaginary linear coordinate and linear momentum terms is constructed and analyzed in detail. The operator η+\eta_+ is found, based on which, a real spectrum and a positive-definite inner product, together with the probability explanation of wave functions, the orthogonality of eigenstates, and the unitarity of time evolution, are obtained for the non-Hermitian and non-PTPT-symmetric Hamiltonian. Moreover, this Hamiltonian turns out to be coupled when it is extended to the canonical noncommutative space with noncommutative spatial coordinate operators and noncommutative momentum operators as well. Our method is applicable to the coupled Hamiltonian. Then the first and second order noncommutative corrections of energy levels are calculated, and in particular the reality of energy spectra, the positive-definiteness of inner products, and the related properties (the probability explanation of wave functions, the orthogonality of eigenstates, and the unitarity of time evolution) are found not to be altered by the noncommutativity.Comment: 15 pages, no figures; v2: clarifications added; v3: 16 pages, 1 figure, clarifications made clearer; v4: 19 pages, the main context is completely rewritten; v5: 25 pages, title slightly changed, clarifications added, the final version to appear in PLOS ON

    Estimation of paleo-firing temperatures using luminescence signals for the volcanic lava baked layer in Datong, China

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    Eight paleo-fired samples from the baked layer in different depths under the lava and one unfired sample were collected from Datong, China. Fine quartz grains (4–11 μm) from samples were used for probing into relationship between luminescence signals and paleo-firing temperatures. Findings from the re-firing experiments indicated that using thermoluminescence (TL) and optically stimulated luminescence (OSL) sensitivity changes could estimate the paleo-firing temperatures of samples: (1) 110 °C TL sensitivity change rate against the re-firing temperature can tell whether the sample has been fired to temperatures above 500 °C or not; (2) 150 °C TL sensitivity against the re-firing temperature can indicate whether the sample has been fired to temperatures above 900 °C or not; (3) the more specific paleo-firing temperatures can be estimated by comparing the ratio of OSL and 150 °C TL sensitivities against re-firing temperatures. Results showed that the paleo-firing temperatures of the eight lava-baked samples decreased exponentially with the distance from the lava. Based on the estimated temperature profile, the temperature of the lava was estimated to be about 1100 °C.postprin

    Neural Enquirer: Learning To Query Tables In Natural Language

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    We propose NEURAL ENQUIRER — a neural network architecture for answering natural language (NL) questions based on a knowledge base (KB) table. Unlike existing work on end-to-end training of semantic parsers [13, 12], NEURAL ENQUIRER is fully “neuralized”: it finds distributed representations of queries and KB tables, and executes queries through a series of neural network components called “executors”. Executors model query operations and compute intermediate execution results in the form of table annotations at different levels. NEURAL ENQUIRER can be trained with gradient descent, with which the representations of queries and the KB table are jointly optimized with the query execution logic. The training can be done in an end-to-end fashion, and it can also be carried out with stronger guidance, e.g., step-by-step supervision for complex queries. NEURAL ENQUIRER is one step towards building neural network systems that can understand natural language in real-world tasks. As a proofof-concept, we conduct experiments on a synthetic QA task, and demonstrate that the model can learn to execute reasonably complex NL queries on small-scale KB tables.postprin

    Over one hundred years of trace metal fluxes in the sediments of the Pearl River Estuary, South China

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    Author name used in this publication: C. C. M. IpAuthor name used in this publication: X. D. LiAuthor name used in this publication: G. ZhangAuthor name used in this publication: O. W. H. WaiAuthor name used in this publication: Y. S. Li2003-2004 > Academic research: refereed > Publication in refereed journalAccepted ManuscriptPublishe

    Two-photon excited photoluminescence in InGaN multi-quantum-wells structures

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    In this work, we report on the two-photon absorption induced luminescence of InGaN multiple quantum wells grown on sapphire. When the sample was excited by femtosecond near-infrared laser pulses at room temperature, an intense luminescence signal peaked at ∼415 nm from the sample was observed, which indicates strong nonlinear optical effect in InGaN quantum well structures. The interferometric autocorrelated luminescence traces were recorded to verify the second order nonlinearity of the luminescence. In addition, the strong second harmonic generation signal of the excitation laser was also observed. The mechanism of the two-photon excited photoluminescence in InGaN quantum wells was discussed.published_or_final_versionpublished_or_final_versio
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