122 research outputs found

    Progress in Chinese research on water masses and circulation in the Arctic and subarctic ocean

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    The Arctic Ocean and Arctic sea ice have undergone a series of rapid changes. Oceanographic surveying has become one of the key missions of the Chinese National Arctic Research Expeditions since 1999. Using the data obtained in these surveys and from other sources, Chinese researchers have carried out a series of studies in the field of Arctic physical oceanography. The Near Sea-surface Temperature Maximum, freshwater content and heat flux in different regions of the Arctic have drawn wide attention from Chinese researchers. Arctic circulation is changing with the decline of sea ice, which is also influencing the structure and distribution of water masses. Studies have also focused on these issues. In this paper, the main results of research on water masses, currents, the structure of the upper ocean and other major hydrological phenomena over the past two decades are summarized

    The “Groundwater Benefit Zone”, Proposals, Contributions and New Scientific Issues

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    The groundwater has great potential for water resource utilization, accounting for about a quarter of vegetation transpiration globally and contributing up to 84% in shallow groundwater areas. However, in irrigated agricultural regions or coastal areas with shallow groundwater levels, due to the high groundwater salinity, the contribution of groundwater to transpiration is small and even harmful. This paper proposes a new conception of groundwater benefit zone in the groundwater-soil–plant-atmosphere continuum (GSPAC) system. Firstly, it analyzes the mutual feedback processes of the underground hydrological process and aboveground farmland ecosystem. Secondly, it elaborates on the regional water and salt movement model proposed vital technologies based on the optimal regulation of the groundwater benefit zone and is committed to building a synergy that considers soil salt control and groundwater yield subsidies. Finally, based on the GSPAC system water-salt coupling transport mechanism, quantitative model of groundwater benefit zone, and technical parameters of regional water-salt regulation and control, the scientific problems and development opportunities related to the conception of groundwater benefit zone have been prospected

    Carbonization Resistance of Reinforced Concrete under Bending Load

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    Fly ash has been used more and more often to take the place of cement as the admixture of concrete in the construction of concrete buildings. However, with the increase of the carbon dioxide (CO2) concentration in the atmosphere, carbonization damage has become an essential factor affecting the durability of fly ash concrete. Here a long-term bending load device was developed to explore how the pouring surface and the bending load affect the carbonization resistance of reinforced concrete under rapid carbonization. In addition, the relationship between the bending-tension and bending-compression loads with respect to the carbonization damage of test blocks was also investigated. Due to the differences in the concrete compactness, the carbonization depth of the pouring surface was found to be greater than that of the bottom at the same position. To a certain extent, with the increasing bending-load stress, different carbonization resistances were observed in the bending-tension zone and the bending-compression zone of the concrete test blocks. Meanwhile, to study the relationship between the carbonization damages in the bending-tension zone and the bending-compression zone of concrete test blocks, a carbonization influence coefficient of bending tension-compression load was proposed, which provides a convenient and scientific guidance for the detection and evaluation of concrete carbonization damages in practical engineering. &nbsp

    The impact of the Pan-African-aged tectonothermal event on high-grade rocks at Mount Brown, East Antarctica

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    This study presents monazite and rutile U–Pb and hornblende and biotite 40Ar/39Ar geochronological data for high-grade rocks of the eastern Grenville-aged Rayner orogen at Mount Brown in order to analyse the extent and degree of Pan-African-aged reworking. Monazite from paragneiss yields U–Pb ages of 910 Ma for larger granular grains and 670–630 Ma for smaller globular beads around garnet porphyroblasts or hosted by symplectites. Rutile from leucogneiss yields U–Pb ages of 520–515 Ma. Hornblende and biotite from different rock types yield 40Ar/39Ar plateau ages of 744 and 520–505 Ma, respectively. Combining these results with published zircon U–Pb age data suggests that granulite facies metamorphism occurred at 910 Ma, with a local low-temperature fluid flow event at 670–630 Ma and thermal reworking at 520–505 Ma. The older age of 744 Ma may reflect cooling or partial resetting of the hornblende 40Ar/39Ar system, indicating that Pan-African-aged reworking did not exceed temperatures much higher than the hornblende Ar closure temperature. These data also suggest that the complete isotopic resetting of some minerals may occur without the growth of new mineral phases, providing an example of the style of reworking that is likely to occur in polymetamorphic terranes.This research was supported by the National Natural Science Foundation of China (No. 41530209), Central Public-Interest Scientific Institution Basal Research Fund (No. JYYWF201819) and Geological Investigation Project of the Chinese Geological Survey (No. DD20190579)

    Crafting NPB with tetraphenylethene: a win–win strategy to create stable and efficient solid-state emitters with aggregation-induced emission feature, high hole-transporting property and efficient electroluminescence

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    N,N′-Di-(1-naphthyl)-N,N′-diphenyl-(1,1′-biphenyl)-4,4′-diamine (NPB) possesses high thermal and morphological stability and is one of the well-known hole-transporting materials for the fabrication of organic light-emitting diodes (OLEDs). Modification of NPB by the covalent integration of tetraphenylethene (TPE) into its structure dramatically changes its emission behavior: the resulting adduct (TPE–NPB) is highly emissive in the aggregated state, showing a novel phenomenon of aggregation-induced emission (AIE). The adduct is thermally and morphologically stable. Non-doped multilayer electroluminescence (EL) devices using TPE–NPB as an emitting layer were fabricated, which emitted green light with a maximum luminance and current efficiency of 11[thin space (1/6-em)]981 cd m−2 and 11.9 cd A−1, respectively. Even better device performances are observed in the bilayer device without NPB. Our strategy takes the full advantage of the AIE property in the solid state and retains the inherent properties of conventional luminophores. It opens a new avenue in the development of stable and efficient solid-state fluorescent materials for OLED application

    A-6G and A-20C Polymorphisms in the Angiotensinogen Promoter and Hypertension Risk in Chinese: A Meta-Analysis

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    BACKGROUND: Numerous studies in Chinese populations have evaluated the association between the A-6G and A-20C polymorphisms in the promoter region of angiotensinogen gene and hypertension. However, the results remain conflicting. We carried out a meta-analysis for these associations. METHODS AND RESULTS: Case-control studies in Chinese and English publications were identified by searching the MEDLINE, EMBASE, CNKI, Wanfang, CBM, and VIP databases. The random-effects model was applied for dichotomous outcomes to combine the results of the individual studies. We finally selected 24 studies containing 5932 hypertensive patients and 5231 normotensive controls. Overall, we found significant association between the A-6G polymorphism and the decreased risk of hypertension in the dominant genetic model (AA+AG vs. GG: P=0.001, OR=0.71, 95%CI 0.57-0.87, P(heterogeneity)=0.96). The A-20C polymorphism was significantly associated with the increased risk for hypertension in the allele comparison (C vs. A: P=0.03, OR=1.14, 95%CI 1.02-1.27, P(heterogeneity)=0.92) and recessive genetic model (CC vs. CA+AA: P=0.005, OR=1.71, 95%CI 1.18-2.48, P(heterogeneity)=0.99). In the subgroup analysis by ethnicity, significant association was also found among Han Chinese for both A-6G and A-20C polymorphisms. A borderline significantly decreased risk of hypertension between A-6G and Chinese Mongolian was seen in the allele comparison (A vs. G: P=0.05, OR=0.79, 95%CI 0.62-1.00, P(heterogeneity)=0.84). CONCLUSION: Our meta-analysis indicated significant association between angiotensinogen promoter polymorphisms and hypertension in the Chinese populations, especially in Han Chinese
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