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- Yu, Jun-Chao, et al.
(författare)
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Levels and distribution of short chain chlorinated paraffins in seafood from Dalian, China
- 2014
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Ingår i: Huan jing ke xue= Huanjing kexue / [bian ji, Zhongguo ke xue yuan huan jing ke xue wei yuan hui "Huan jing ke xue" bian ji wei yuan hui.]. - Beijing : Ke xue zhu ban she. - 0250-3301. ; 35:5, s. 1955-1961
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Tidskriftsartikel (refereegranskat)abstract
- Seafood samples were collected from Dalian, China to study the accumulation and distribution characteristics of short chain chlorinated paraffins (SCCPs) by GC/ECNI-LRMS. Sum of SCCPs (dry weight) were in the range of 77-8 250 ng.g-1, with the lowest value in Scapharca subcrenata and highest concentration in Neptunea cumingi. The concentrations of sum of SCCPs (dry weight) in fish, shrimp/crab and shellfish were in the ranges of 100-3 510, 394-5 440, and 77-8 250 ng.g-1 , respectively. Overall, the C10 and C11 homologues were the most predominant carbon groups of SCCPs in seafood from this area,and a relatively higher proportion of C12-13 was observed in seafood with higher concentrations of sum of SCCPs . With regard to chlorine content, Cl1,, CI8 and CI6 were the major groups. Significant correlations were found among concentrations of different SCCP homologues (except C1, vs. Cl10 ) , which indicated that they might share the same sources and/or have similar accumulation, migration and transformation processes.
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| 2. |
- Di, Jing, et al.
(författare)
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A novel composite electrolyte based on CeO2 for low temperature solid oxide fuel cells
- 2008
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Ingår i: Journal of Inorganic Materials. - 1000-324X. ; 23:3, s. 573-577
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Tidskriftsartikel (refereegranskat)abstract
- A novel composite material based on mixture of samarium-doped ceria (SDC)-carbonate was studied as electrolyte in low temperature solid oxide fuel cells. The phase and microstructures of composite electrolyte were examined by XRD and SEM. The electrical conductivity was investigated by AC impedance spectroscopy at 400-700 degrees C in different atmospheres. An abrupt change in the conductivity at about 500 degrees C indicates that different mechanisms affect transfer in different temperature ranges. The conductivity increases with the carbonate fraction above 500 degrees C. The conductivity in reduce atmosphere is higher than that in oxide atmosphere. An anode-supported fuel cell using SDC-carbonate as electrolyte was fabricated and tested. The result shows that all the composite electrolytes exhibit better performance than pure SDC electrolyte. The electrolyte with 20wt% carbonate can achieve the highest power density of 415mW center dot cm(-2) and an open circuit voltage of 1.00V at 500 degrees C.
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| 5. |
- Wang, Xi, et al.
(författare)
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氨曲南竞争性抑制NDM-1对β-内酰胺类抗生素的水解
- 2019
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Ingår i: Journal of Shanxi University (Natural Science Edition). ; :2021-01
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Tidskriftsartikel (refereegranskat)abstract
- We investigated the effect of Aztreonam on hydrolysis of β-lactam antibiotics by MBL using New Delhi Metallo-β-lactamase-1(NDM-1) as a model. The results showed that Aztreonam significantly inhibited hydrolysis of Nitrocefin and Meropenem by soluble NDM-1, but also inhibited hydrolysis of Penicillin G by CPG beads immobilized NDM-1(NDM-1 beads). Moreover, in spite of extensive washing for multiple times, the activity to hydrolyze Penicillin G by the Aztreoman pre-treated NDM-1 beads was just partially recovered. These data suggest that Aztreonam can covalently and stably bind on NDM-1, thus efficiently inhibiting hydrolysis of other kinds of β-lactam antibiotics by NDM-1 in a competitive way.
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| 6. |
- Xin, Yan-Bo, et al.
(författare)
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Research progress of hydrogen tunneling in two-dimensional materials
- 2017
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Ingår i: Wuli xuebao. - : CHINESE PHYSICAL SOC. - 1000-3290. ; 66:5
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Forskningsöversikt (refereegranskat)abstract
- One-atom-thick material such as graphene, graphene derivatives and graphene-like materials, usually has a dense network lattice structure and therefore dense distribution of electronic clouds in the atomic plane. This unique structure makes it have great significance in both basic research and practical applications. Studies have shown that molecules, atoms and ions are very difficult to permeate through these above-mentioned two-dimensional materials. Theoretical investigations demonstrate that even hydrogen, the smallest in atoms, is expected to take billions of years to penetrate through the dense electronic cloud of graphene. Therefore, it is generally considered that one-atom-thin materialis impermeable for hydrogen. However, recent experimental results have shown that the hydrogen atoms can tunnel through graphene and monolayer hexagonal boron nitride at room temperature. The existence of defects in one-atomthin material can also effectively reduce the barrier height of the hydrogen tunneling through graphene. Controversy exists about whether hydrogen particles such as atoms, ions or hydrogen molecules can tunnel through two-dimensional materials, and it has been one of the popular topics in the fields of two-dimensional materials. In this paper, the recent research progressof hydrogen tunneling through two-dimensional materials is reviewed. The characteristics of hydrogen isotopes tunneling through different two-dimensional materials are introduced. Barrier heights of hydrogen tunneling through different graphene and graphene-like materials are discussed and the difficulties in its transition are compared. Hydrogen cannot tunnel through the monolayer molybdenum disulfide, only a little small number of hydrogen atoms can tunnel hrough graphene and hexagonal boron nitride, while hydrogen is relatively easy to tunnel through silicene and phosphorene. The introduction of atomic defects or some oxygen-containing functional groups into the two-dimensional material is discussed, which can effectively reduce the barrier height of the hydrogen tunneling barrier. By adding the catalyst and adjusting the temperature and humidity of the tunneling environment, the hydrogen tunneling ability can be enhanced and the hydrogen particles tunneling through the two-dimensional material can be realized. Finally, the applications of hydrogen tunneling through two-dimensional materials in ion-separation membranes, fuel cells and hydrogen storage materials are summarized. The potential applications of hydrogen permeable functional thin film materials, lithium ion battery electrode materials and nano-channel ions in low energy transmission are prospected. The exact mechanism of hydrogen tunneling through two-dimensional material is yet to be unravelled. In order to promote these applications and to realize large-scale production and precision machining of these two-dimensional materials, an in-depth understanding of the fundamental questions of the hydrogen tunneling mechanism is needed. Further studies are needed to predict the tunneling process quantitatively and to understand the effects of catalyst and the influences of chemical environments.
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