644 research outputs found

    Bundle adjustment for data processing of theodolite industrial surveying system

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    Author name used in this publication: 邹峥嵘, ZOU Zheng-rongAuthor name used in this publication: 丁晓利, DING Xiao-liAuthor name used in this publication: 曾卓乔, ZENG Zhuo-qiaoAuthor name used in this publication: 何凭宗, HE Ping-zongJournal title in Traditional Chinese: 中國有色金屬學報 (英文版)2000-2001 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishe

    On the Link between the Subseasonal Evolution of the North Atlantic Oscillation and East Asian Climate

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    We analyse the impact of the North Atlantic Oscillation (NAO) on the climate of East Asia at subseasonal time scales during both winter and summer. These teleconections have mainly been investigated at seasonal and longer time scales, while higher-frequency links are largely unexplored. The NAO is defined using extended empirical orthogonal functions on pentad-mean observations, which allows to elucidate the oscillation’s spatial and temporal evolution and clearly separate the development and decay phases. The downstream dynamical imprint and associated temperature and precipitation anomalies are quantified by means of a linear regression analysis. It is shown that the NAO generates a significant climate response over East Asia during both the dry and wet seasons, whose spatial pattern is highly dependent on the phase of the NAO’s life cycle. Temperature and precipitation anomalies develop concurrently with the NAO mature phase, and reach maximum amplitude 5–10 days later. These are shown to be systematically related to mid and high-latitude teleconnections across the Eurasian continent via eastward-propagating quasi-stationary Rossby waves instigated over the Atlantic and terminating in the northeastern Pacific. These findings underscore the importance of rapidly evolving dynamical processes in governing the NAO’s downstream impacts and teleconnections with East Asia.</p

    The importance of imprinting in the human placenta.

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    As a field of study, genomic imprinting has grown rapidly in the last 20 years, with a growing figure of around 100 imprinted genes known in the mouse and approximately 50 in the human. The imprinted expression of genes may be transient and highly tissue-specific, and there are potentially hundreds of other, as yet undiscovered, imprinted transcripts. The placenta is notable amongst mammalian organs for its high and prolific expression of imprinted genes. This review discusses the development of the human placenta and focuses on the function of imprinting in this organ. Imprinting is potentially a mechanism to balance parental resource allocation and it plays an important role in growth. The placenta, as the interface between mother and fetus, is central to prenatal growth control. The expression of genes subject to parental allelic expression bias has, over the years, been shown to be essential for the normal development and physiology of the placenta. In this review we also discuss the significance of genes that lack conservation of imprinting between mice and humans, genes whose imprinted expression is often placental-specific. Finally, we illustrate the importance of imprinting in the postnatal human in terms of several human imprinting disorders, with consideration of the brain as a key organ for imprinted gene expression after birth

    Measurement of the matrix element for the decay η′→ηπ +π -

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    The Dalitz plot of η⊃′→ηπ⊃+π⊃- decay is studied using (225.2±2.8)×106 J/ψ events collected with the BESIII detector at the BEPCII e⊃+e⊃- collider. With the largest sample of η⊃′ decays to date, the parameters of the Dalitz plot are determined in a generalized and a linear representation. Also, the branching fraction of J/ψ→γη⊃′ is determined to be (4.84±0.03±0.24)×10⊃-3, where the first error is statistical and the second systematic. © 2011 American Physical Society.published_or_final_versio

    First observation of the decays χcJ→π0π0π0π0

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    We present a study of the P-wave spin-triplet charmonium χ cJ decays (J=0, 1, 2) into π0π0π0π0. The analysis is based on 106×106 ψ⊃′ decays recorded with the BESIII detector at the BEPCII electron positron collider. The decay into the π0π0π0π0 hadronic final state is observed for the first time. We measure the branching fractions B(χ c0→π0π0π0π0)=(3.34±0. 06±0.44)×10⊃-3, B(χ c1→π0π0π0π0) =(0.57±0.03±0.08)×10⊃-3, and B(χ c2→π0π0π0π0)=(1.21±0.05±0.16) ×10⊃-3, where the uncertainties are statistical and systematical, respectively. © 2011 American Physical Society.published_or_final_versio

    Controllable Synthesis of Magnesium Oxysulfate Nanowires with Different Morphologies

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    One-dimensional magnesium oxysulfate 5Mg(OH)2 · MgSO4 · 3H2O (abbreviated as 513MOS) with high aspect ratio has attracted much attention because of its distinctive properties from those of the conventional bulk materials. 513MOS nanowires with different morphologies were formed by varying the mixing ways of MgSO4 · 7H2O and NH4OH solutions at room temperature followed by hydrothermal treatment of the slurries at 150 °C for 12 h with or without EDTA. 513MOS nanowires with a length of 20–60 μm and a diameter of 60–300 nm were prepared in the case of double injection (adding MgSO4 · 7H2O and NH4OH solutions simultaneously into water), compared with the 513MOS with a length of 20–30 μm and a diameter of 0.3–1.7 μm in the case of the single injection (adding MgSO4 · 7H2O solution into NH4OH solution). The presence of minor amount of EDTA in the single injection method led to the formation of 513MOS nanowires with a length of 100–200 μm, a diameter of 80–200 nm, and an aspect ratio of up to 1000. The analysis of the experimental results indicated that the hydrothermal solutions with a lower supersaturation were favorable for the preferential growth of 513MOS nanowires along b axis

    Study of a00(980)-f0(980) mixing

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    Using samples of 2.25×108 J/ψ events and 1.06×108 ψ ′ events collected with the BES III detector, we study the f 0(980)→a00(980) and a00(980)→f 0(980) transitions in the processes J/ψ→φf 0(980) →φa00(980) and χ c1→π0a00(980)→π0f 0(980), respectively. Evidence for f 0(980)→a00(980) is found with a significance of 3.4σ, while in the case of a00(980)→f 0(980) transition, the significance is 1.9σ. Measurements and upper limits of both branching ratios and mixing intensities are determined. © 2011 American Physical Society.published_or_final_versio

    Enhanced convective heat transfer using graphene dispersed nanofluids

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    Nanofluids are having wide area of application in electronic and cooling industry. In the present work, hydrogen exfoliated graphene (HEG) dispersed deionized (DI) water, and ethylene glycol (EG) based nanofluids were developed. Further, thermal conductivity and heat transfer properties of these nanofluids were systematically investigated. HEG was synthesized by exfoliating graphite oxide in H2 atmosphere at 200°C. The nanofluids were prepared by dispersing functionalized HEG (f-HEG) in DI water and EG without the use of any surfactant. HEG and f-HEG were characterized by powder X-ray diffractometry, electron microscopy, Raman and FTIR spectroscopy. Thermal and electrical conductivities of f-HEG dispersed DI water and EG based nanofluids were measured for different volume fractions and at different temperatures. A 0.05% volume fraction of f-HEG dispersed DI water based nanofluid shows an enhancement in thermal conductivity of about 16% at 25°C and 75% at 50°C. The enhancement in Nusselts number for these nanofluids is more than that of thermal conductivity

    Adult Raphe-Specific Deletion of Lmx1b Leads to Central Serotonin Deficiency

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    The transcription factor Lmx1b is essential for the differentiation and survival of central serotonergic (5-HTergic) neurons during embryonic development. However, the role of Lmx1b in adult 5-HTergic neurons is unknown. We used an inducible Cre-LoxP system to selectively inactivate Lmx1b expression in the raphe nuclei of adult mice. Pet1-CreERT2 mice were generated and crossed with Lmx1bflox/flox mice to obtain Pet1-CreERT2; Lmx1bflox/flox mice (which termed as Lmx1b iCKO). After administration of tamoxifen, the level of 5-HT in the brain of Lmx1b iCKO mice was reduced to 60% of that in control mice, and the expression of tryptophan hydroxylase 2 (Tph2), serotonin transporter (Sert) and vesicular monoamine transporter 2 (Vmat2) was greatly down-regulated. On the other hand, the expression of dopamine and norepinephrine as well as aromatic L-amino acid decarboxylase (Aadc) and Pet1 was unchanged. Our results reveal that Lmx1b is required for the biosynthesis of 5-HT in adult mouse brain, and it may be involved in maintaining normal functions of central 5-HTergic neurons by regulating the expression of Tph2, Sert and Vmat2
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