89 research outputs found

    海洋放射化学

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    Marine radiochemistry deals with the content and speciation of radionuclides in the oceans. By using their distributions in the oceans, the source and sink, migration and transport processes of the radionuclides are studied, and their inventories in some compartments are evaluated. In this paper, the development history for marine radiochemistry at home and abroad is briefly introduced. The main fields of oceanography applying radiochemistry are general circulation, seawater mixing, particle dynamics and marine radiochronology. The future major subjects of marine radiochemistry are the fluxes and time scales of biogeochemical cycles, post marine environment change and accumulation and ecological effect of radionuclides in the sea area adjacent nuclear power plants. The main issues of marine radiochemistry are addressed in this paper as well

    Proteomic analysis of the biomass hydrolytic potentials of Penicillium oxalicum lignocellulolytic enzyme system

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    Additional file 2: Table S1. The functional annotations of proteins identified in the proteome of SP. Mass spectrometry-based proteomics study was performed to comprehensively dissect the lignocellulolytic enzyme profile of SP. Accession, Protein name, PSM, Calc. MW, CBM, Calc. pI and CAZy family of identified proteins were shown

    Tuning the synthesis of polymetallic-doped ZIF derived materials for efficient hydrogenation of furfural to furfuryl alcohol

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    Cu, Co and Zn modified N-doped porous carbons (CuCo/Zn@NPC) are prepared using a polymetallic homogeneous doping and self-templating method as high performance non-noble metal catalysts for the hydrogenation of furfural (FF) to furfuryl alcohol (FAL). The CuCo/Zn@NPC-600 catalyst after treatment at 600 °C shows a superior catalytic activity with nearly 100% conversion of FF and an almost 100% selectivity of FAL using H2 at 140 °C. Meanwhile in the catalytic transfer hydrogenation (CTH) using 2-propanol as a H-donor, the conversion of FF reaches 95.8% and the selectivity of FAL is 99.1%. The results show that the Zn dopant leads to 37.3 times higher yield on the CuCo/Zn@NPC-600 catalyst than that on CuCo@NPC-600, and 2.3 times higher than that on Co/Zn@NPC-600 with Cu dopants. The efficient activity of the CuCo/Zn@NPC-600 catalyst is mainly due to the highly dispersed metal nanoparticles, the advanced porous structure resulting from Zn escape from the precursor template, and the synergistic effect between Cu and Co. Furthermore, the CuCo/Zn@NPC-600 catalyst exhibits good recyclability in FF hydrogenation in four cycle tests. The advanced synthesis method using a homogeneous doping and self-templating strategy sheds light on preparing effective catalysts for hydrogenation of biomass-based compounds

    Efficient single-atom Ni for catalytic transfer hydrogenation of furfural to furfuryl alcohol

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    The employment of single-atom catalysts in the catalytic transfer hydrogenation (CTH) of furfural (FF) to furfuryl alcohol (FAL) have never been effectively explored. Herein, Ni single-atoms supported on nitrogen doped carbon (Ni-SAs/NC) catalyst is synthesized and first ever utilized in CTH of FF to FAL. Atomically dispersed Ni-N4 sites change the electron density at the metal center and exhibit specific adsorption and desorption to FF and FAL, promoting an outstanding catalytic performance with turnover frequency (TOF) of 832 h-1 and selectivity as high as 97.1 at 130 oC for 2 h. Such performance is 9-fold higher than that of supported Ni nanocatalysts. The Ni-SAs/NC catalyst also exhibits superior stability for CTH of FF and excellent catalytic activity for other α,β-unsaturated aldehydes. This work provides a new strategy of producing green chemical compounds using catalytic biomass conversion and suggests the future application of long-lasting single-atom catalysts for emerging sustainable technologies

    Screen printing directed synthesis of covalent organic framework membranes with water sieving property

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    Screen printing is introduced to direct the synthesis of crack-free and thickness-tunable TpPa(OH)2 covalent organic framework membranes. A smooth precursor layer is firstly screen printed and then fully crystallised into TpPa(OH)2 membrane. Molecular-scale pores endow the membrane fast water-sieving property, which is promising in water desalination

    AMS measurement of 53Mn and its initial application at CIAE

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    The determination of cosmogenic 53Mn in terrestrial archives has important applications, such as burial ages, exposure age and erosion rates. Accelerator mass spectrometry (AMS) is the most sensitive technique to detect minute amounts of 53Mn. 53Mn measurements were developed at the China Institute of Atomic nergy (CIAE) using the DE-Q3D equipped AMS system. This approach was recently optimized with the goal to reach the sensitivity required for AMS measurements of 53Mn in deep-sea ferromanganese crust (DSFC) samples. Based on these improvements of sample preparation, current beam transmission and so on, 53Mn in two samples of DSFC was measured by AMS. The ratios of 53Mn/Mn corresponding to an age of 3.77 ± 0.42 and 13.73 ± 2.74 Ma by 129I dating method are (5.01 ± 2.15) 10 13 and (1.90 ± 0.96) 10 13. The ratios are close to the experimental reference values, deduced from the previous research. The experimental progress, performances and results are presented in this contribution.This work was mainly supported by the National Natural Science Foundations of China (NSFC), under Grant No. 11075221, and a partly supported by the National Natural Science Foundation of China under Grant Nos. 10705054, 41073044 and 11265005

    Moisture Source Tagging Confirming the Polar Amplification Effect in Amplifying the Temperature-delta O-18 Temporal Slope Since the LGM

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    Stable water isotopologues in paleoclimate archives (delta 18O) have been widely used as an indicator to derive past climate variations. The modern observed spatial delta 18O-temperature relation in the middle and high latitudes has been used to infer the paleotemperatures changes from ice core data. However, various studies have shown that the spatial slope is larger than the temporal slope at the drill site by a factor of 2. Physically, the different spatial and temporal slope has been suggested to result from the amplified local surface air temperature cooling in the polar region at Last Glacial Maximum (LGM), according to the slope ratio equation derived in our previous study. To explicitly confirm the "polar amplification" effect in understanding the differences between temporal and spatial isotope-temperature relations, here we use the same isotope-enabled atmospheric general circulation model with a moisture-tracing module embedded to quantitatively estimate the contributions of different sources to the precipitated heavy oxygen isotopes in the middle and high latitudes. Our results show that the major sources of delta 18Oin precipitation over middle and high latitudes are from oceans where the sea surface temperature cooling at Last Glacial Maximum (LGM) is less than -2 degrees C, while the local moisture sources with a higher cooling can be also relevant for polar regions, such as north Greenland. Additionally, the neglect of the strengthened local inversion layer strength at LGM could be the main cause for the overestimated source temperature cooling by the slope ratio equation, especially for the polar regions in the Northern Hemisphere
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