[en] The Quasi-Biennial Oscillation (QBO) and the El Niño–Southern Oscillation (ENSO) are two dominant modes of climate variability at the Equator. There exist observational evidences of mutual interactions between these two phenomena, but this possibility has not been widely studied using climate model simulations. In this work we assess how current models represent the ENSO/QBO relationship, in terms of the response of the amplitude and descent rate of stratospheric wind regimes, by analyzing atmosphere-only and ocean–atmosphere coupled simulations from a large multi-model ensemble. The annual cycle of the QBO descent rate is well represented in both coupled and uncoupled models. Previous results regarding the phase alignment of the QBO after the 1997/98 strong warm ENSO event are confirmed in a larger ensemble of uncoupled experiments. However, in general we find that a relatively high horizontal resolution is necessary to reproduce the observed modulation of the QBO descent rate under strong ENSO events, while the amplitude response is generally weak at any horizontal resolution. We argue that biases in the mean state and over-dependence on parameterized wave forcing undermine the realism of the simulated coupling between the ocean and the stratosphere in the tropics in current climate models. The modulation of the QBO by the ENSO in a high emission scenario consistently differs from that in the historical period, suggesting that this relationship is sensitive to changes in the large-scale circulation.

[en] The problem of Li–O₂ batteries lies in the lack of high performance and low-cost catalyst that can promote the decomposition of discharge products. The trouble is even more serious when it cycles in CO₂. Herein, we synthesize a nitrogen (N) and sulfur (S) co-doped 3D graphene@NiO (N, S-3DG@NiO) composite as a bi-functional electrode catalyst, which can concurrently support the stable cycling of Li–O₂ and Li–CO₂ batteries. In this design, the N, S-3DG@NiO has three-dimensional porous structure, which can provide extra storage space for discharge products, and N and S co-doping provides more reaction active sites. The bi-functional electrode catalyst delivers a high discharge capacity of 17 300 mAh g⁻¹ and excellent cyclability (more than 50 cycles, limited capacity 500 mA g⁻¹) when it is applied for Li–O₂ batteries. In addition, the N, S-3DG@NiO catalyst also exhibits a large discharge capacity of 13 400 mAh g⁻¹ when it is used as cathode for Li–CO₂ batteries (more than 50 cycles, limited capacity 500 mA g⁻¹). This study not only provides a high efficiency bi-functional cathode catalyst for Li–O₂ and Li–CO₂ batteries, but also promotes the development of high specific energy batteries. (paper)

[en] Synthesis method is crucial to the improved electrochemical performances of LiMnPO${}_4$ materials with poor electronic and ionic conductivity for large-scale preparation. Here, carbon-coated LiMn${}_{0.8}$Fe${}_{0.2}$PO${}_4$ materials were synthesized through a rheological phase-assisted solid-state method combined with freeze-drying. Effect of different carbon sources on the structure, morphology, and electrochemical performance of as-prepared LiMn${}_{0.8}$Fe${}_{0.2}$PO${}_4$ materials was investigated. The results suggest that LiMn${}_{0.8}$Fe${}_{0.2}$PO${}_4$ materials with citric acid as carbon sources show a high discharge capacity with 164, 122, and 106 mA h g${}^{-<!--\; ???\; -->1}$ at 0.1, 1, and 5 C, and a capacity retention of around 99.6% after 100 cycles at 1 C. This can be attributed to higher surface area, intense peak of sp${}^2$ N–C=N bonds, and uniform particle distribution resulting from the rheological phase formed using citric acid as carbon sources combined with freeze-drying. The rheological phase-assisted solid-state method is a promising route for production of LiMn${}_{0.8}$Fe${}_{0.2}$PO${}_4$ materials with excellent performances.

[en] Li₄Ti₅O₁₂/C composite was successfully synthesized by a microwave-assisted method using polyacrylamide (PAM) as both the template and the carbon source. The structure and morphology of the products were characterized by means of x-ray diffraction and field emission scanning electron microscopy. The results indicate that the Li₄Ti₅O₁₂/C powder synthesized by a microwave-assisted method has good crystallinity and has sub-micrometer average particle size. Electrochemical tests showed that Li₄Ti₅O₁₂/C composite synthesized by the microwave-assisted method with PAM exhibits a specific capacity of 167.8 and 135.5 mAh g^-1 at the 0.2 and 5 C rates. Compared with Li₄Ti₅O₁₂ prepared by the microwave-assisted method using PAM as the template in air, Li₄Ti₅O₁₂ prepared in N₂ has a better electrochemical performance; this is due to pyrolytic carbon increasing the electronic conductivity of the material. During the process of synthesis, the particle morphology of the Li₄Ti₅O₁₂/C composite gets adjusted and controlled by the thermal impetus of PAM template decomposition.

[en] The potential link between decreasing Barents-Kara sea ice and cold winters in Europe is investigated using the enhanced resolution (horizontal atmospheric resolution of $\sim <!--\; ???\; -->80\text{km}$) global, coupled climate model EC-Earth. Nudging sea ice only in the Barents-Kara Seas, five configurations of sea ice covers are used to assess the importance of the amount of sea ice in this region. Nudging in the coupled model is achieved by modifying the non-solar surface heat flux into the ice/ocean interface. The mean winter temperature response suggests a weak but statistically significant non-linear response with cooling over eastern Europe for moderate sea ice reductions in the Barents-Kara Seas, a weaker but still cold anomaly for minor reductions and warming for major reductions. However, this non-linear response is not reflected in the circulation. Instead, a negative mean sea level pressure anomaly over Barents-Kara Seas intensifies with sea ice reduction. In contrast to this, is the response in the coldest winters over central Europe: the larger the sea ice reduction, the stronger the Scandinavian pattern and the associated easterlies need to be to obtain cold winters over central Europe. The use of a coupled climate model is a potential explanation for the link between the intensified Scandinavian pattern and the cooling over Europe seen in this study, that is not observed in some atmosphere-only model studies.

[en] To understand the sequence characteristics of the plasma membrane intrinsic protein (PIP) and its function in abiotic stress resistance, AgPIP2; 1 gene was cloned from celery variety 'Liuhe Huangxinqin' by RT-PCR. The characteristics of the nucleotides and amino acids of the gene were analyzed by bioinformatics software, and its expression in different tissues and response to abiotic stress were detected by real-time quantitative PCR. The results showed that the gene contained an open reading frame of 861 bp, encoding 286 amino acids. The encoded protein belonged to PIP2 class. Amino acid sequence analysis showed that AgPIP2; 1 had two highly conserved NPA motifs and conserved domains unique to PIP family in higher plants. AgPIP2; 1 had high homology with PIP2 proteins from other species, and showed 97.90%homology with DcPIP2; 1 in carrot. It is close to soybean GmPIP2; 1, carrot DcPIP2; 1, and Mung bean VrPIP2; 1. Real-time quantitative PCR analysis showed that AgPIP2; 1 gene was expressed in celery roots, petioles, and leaves, and exhibited the highest expression in the leaves and the lowest in the roots, showing obvious tissue specificity. In addition, the gene was induced by abiotic stresses such as high temperature, low temperature, drought, and salt, indicating that the gene may be involved in celery resistance against abiotic stresses. This study lay a foundation for further understand the function of AgPIP2; 1 gene and its role in abiotic stress. (authors)

[en] Three kinds of Cu-Sn alloy anodes with different current collectors for lithium ion batteries had been directly prepared by cost-effective and easy to scale-up electro-deposition method. Both the self-standing electrode and the electrode with polypyrrole (PPy) current collector had effects on enhancing the cycle stability and increasing the gravimetric energy density. However, due to the poor conductivity of PPy and the low crystallinity structure of Cu-Sn alloy layer, the high rate performance of Cu-Sn alloy electrode with PPy current collector was unsatisfactory, while the self-standing electrode not only greatly increased the cycle stability and energy density of the whole electrode to a large extent, but also exhibited superior high-current cycle performance. Even cycled at a current density of 6 A g⁻¹ after 700 cycles, the self-standing electrode could still maintain a specific capacity of 332 mA h g⁻¹, which illustrated the potential application prospect of self-standing electrode with higher energy density and power density.

[en] Highlights: • Olivine LiFePO₄ blending can improve the high-voltage cycling performance of LiCoO₂. • LiFePO₄ blending inhibits the broken degree of LiCoO₂ particles and the generation of Co₃O₄. • Olivine LiFePO₄ blending helps to stabilize the layered structure of LiCoO₂ upon cycling. -- Abstract: The structural stability of LiCoO₂ at high voltage is a crucial concern of LiCoO₂ electrode. The experiment in this work have proved that mixed LiCoO₂ and LiFePO₄ electrode can stabilize the layered structure of LiCoO₂ and improve their cycle stability significantly. The SEM images show that a protective thin film was gradually formed on the surface of LiCoO₂ particles during charging and discharging. With the amount of mixed LiFePO₄ increasing, the film increases, which inhibits the broken of the LiCoO₂ particles and the formation of Co₃O₄; The battery built using the mixed LiCoO₂ and LiFePO₄ electrodes shows the best cycle stability when the content of LiFePO₄ is 12 wt%, with the initial discharge specific capacity of 177.9 mA h g⁻¹ and the capacity retention of 77.2% after 200 cycles between 3.0 and 4.5 V at 0.2 C.

[en] A novel modified separator was synthesized with an ultraviolet irradiated polypropylene (PP) membrane and acrylonitrile monomers by a solution grafting reaction. It was demonstrated that polyacrylonitrile (PAN) was grafted on the PP separator surface by analyzing the results of FESEM, ATR–FTIR and XPS. The thermostability and wettability of the PAN-grafted PP (PP-g-PAN) separator were enhanced. Then, Li–S batteries were assembled using the modified separators. The cycling and rate capacity performance is improved clearly because of the higher liquid uptake, smaller porous size, better polysulfides absorption effect and interfacial affinity of the grafted separator. The modified separator can hinder the movement of Li₂S_x effectively to prevent the shuttle effect of a Li–S battery. Therefore, this efficient method has great potential to be applied to the modification of other kinds of polymer membranes.

[en] Highlights: • The thermal performance of aligned, staggered, and cross battery packs is experimentally studied. • The effect of the discharge rate and air inlet temperature on the thermal management system is analyzed. • The energy efficiency of the air cooling battery thermal management system is investigated under various conditions. • The upper limitation for the cooling capacity is demonstrated in this paper. -- Abstract: To comprehensively investigate the characteristics of an air cooling system, a battery pack with 32 high energy density cylindrical lithium-ion batteries is designed in this paper. Using a series of evaluation parameters, the air cooling performances of aligned, staggered, and cross battery packs are experimentally studied and compared at different air inlet velocities. Additionally, the cooling effect and capacity of the air cooling system are investigated by changing the discharge rate and air inlet temperature. Finally, the energy efficiency of the air cooling system under various operating conditions is studied. It is found that the aligned arrangement has the best cooling performance and temperature uniformity, followed by the staggered and finally the cross arrangement. The minimum temperature always occurs in the second column along the direction of the air inlet. The parasitic power consumption increases exponentially with the air inlet velocity, and the aligned arrangement has the lowest power consumption, up to 23% less than that of the cross arrangement. Additionally, the energy efficiency of the air cooling system decreases with the increasing air velocity, and the cooling capacity has an upper limit that is proportional to the discharge rate.