It has recently been demonstrated that the use of anion exchange membranes (AEMs) in vanadium redox flow batteries (VRFBs) can reduce the migration of vanadium ions through the membrane due to the ...Donnan exclusion effect among the positively charged functional groups and vanadium ions. However, AEMs are plagued by low chemical stability in harsh chemical environments. Here we propose and fabricate a pyridinium-functionalized cross-linked AEM for VRFBs. The pyridinium-functionalized bromomethylated poly (2,6-dimethyl-1,4-phenylene oxide) exhibits a superior chemical stability as a result of the strengthened internal cross-linking networks and the chemical inertness of the polymer backbone. Therefore, the membrane exhibits littler decay in a harsh environment for 20 days during the course of an ex situ immersion test. A cycling test also demonstrates that the VRFB assembled with the membrane enable to retain 80% of the initial discharge capacity over 537 cycles with a capacity decay rate of 0.037% cycle−1. Meanwhile, the membrane also shows a low vanadium permeability and a reasonably high conductivity in supporting electrolytes. Hence, all the measurements and performance tests reported in this work suggest that the membrane is a promising AEM for redox flow batteries to achieve excellent cycling stability and superior cell performance.
Pyridinium-functionalized cross-linked anion exchange membranes are fabricated to address the issue of low chemical stability for vanadium redox flow batteries. The pyridinium-functionalized bromomethylated poly (2,6-dimethyl-1,4-phenylene oxide) (BrPPO/Py) exhibits a superior chemical stability as a result of the strengthened internal cross-linking networks and the chemical inertness of the polymer backbone. A cycling test shows that the VRFBs assembled with BrPPO/Py enable to maintain 80% of the specific discharge capacity over 537 cycles with a capacity decay rate of 0.037% cycle−1 at a current density of 200 mA cm−2. Display omitted
•Pyridinium-functionalized cross-linked BrPPO were fabricated for VRFBs.•The AEMs exhibited a low vanadium permeability and an acceptable conductivity.•The AEMs exhibited a superior chemical stability in an ex situ immersion test.•The VRFBs cycled over 537 cycles with a capacity decay rate of 0.037% cycle−1.
Circular RNAs (circRNAs) represent a class of non-coding RNAs that are widely expressed in mammals. However, it is largely unknown about the function of human circRNAs and the roles of circRNAs in ...human oral squamous cell carcinomas (OSCC). Here we performed a comprehensive study of circRNAs in human OSCC using circRNA and mRNA microarrays, and identified many circRNAs that are differentially expressed between OSCC tissue and paired non-cancerous matched tissue. We further found a circRNA termed circRNA_100290 that served as a critical regulator in OSCC development. We discovered that circRNA_100290 was upregulated and co-expressed with CDK6 in OSCC tissue. Knockdown of circRNA_100290 decreased expression of CDK6 and inhibited proliferation of OSCC cell lines in vitro and in vivo. Via luciferase reporter assays, circRNA_100290 was observed to directly bind to miR-29 family members. Further EGFP/RFP reporter assays showed that CDK6 was the direct target of miR-29b. Taken together, we conclude that circRNA_100290 may function as a competing endogenous RNA to regulate CDK6 expression through sponging up miR-29b family members. Taken together, it indicates that circRNAs may exert regulatory functions in OSCC and may be a potential target for OSCC therapy.
•Copper nanoparticle is proposed as electrocatalyst for VRFBs for the first time.•Propose a binder-free copper nanoparticle decorated electrode.•The energy efficiency is up to 80.1% at 300mAcm−2, ...enhancing more than 17%.•High stability and capacity retention are achieved by battery with copper catalyst.
A copper nanoparticle deposited graphite felt electrode for all vanadium redox flow batteries (VRFBs) is developed and tested. It is found that the copper catalyst enables a significant improvement in the electrochemical kinetics of the V3+/V2+ redox reaction. The battery’s utilization of the electrolyte and energy efficiency are found to be as high as 83.7% and 80.1%, at a current density of 300mAcm−2, which are 53.1% and 17.8% higher than those of the battery without the catalyst. Moreover, the present battery shows a good stability during the cycle test. The results suggest that the inexpensive copper nanoparticle catalyst without tedious preparation process offers a great promise for VRFB application.
In this work, we prepare a highly catalytic and stabilized titanium nitride (TiN) nanowire array-decorated graphite felt electrode for all vanadium redox flow batteries (VRFBs). Free-standing TiN ...nanowires are synthesized by a two-step process, in which TiO2 nanowires are first grown onto the surface of graphite felt via a seed-assisted hydrothermal method and then converted to TiN through nitridation reaction. When applied to VRFBs, the prepared electrode enables the electrolyte utilization and energy efficiency to be 73.9% and 77.4% at a high current density of 300 mA cm−2, which are correspondingly 43.3% and 15.4% higher than that of battery assembled with a pristine electrode. More impressively, the present battery exhibits good stability and high capacity retention during the cycle test. The superior performance is ascribed to the significant improvement in the electrochemical kinetics and enlarged active sites toward V3+/V2+ redox reaction.
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•Propose a binder-free TiN nanowire array-decorated electrode for VRFBs.•Energy efficiency is up to 77.4% at 300 mA cm−2, enhancing more than 15%.•Electrolyte utilization is up to 73.9% at 300 mA cm−2, enhancing more than 43%.•High stability and capacity retention are achieved by present battery.
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•The EEFN embodies the small-world nature and scale-free property at global level.•4 communities are detected to understand the regionalization of EEFN.•Different role played by ...economies in EEFN are identified with centrality measures.•A diversity index is developed to quantify the security of embodied energy supply.
Significant energy flows embodied in international trade have evolved into a complex interconnected flow network. Therefore, this study applies a variety of complex network analysis tools to uncover the structure of embodied energy flow network (EEFN) at global, regional and national level, based on environmentally extended input–output analysis (EEIOA). At global level, small-world nature has been found, implying the economies are highly connected through embodied energy transfer. EEFN is proved to be a heterogeneous network due to the scale-free power-law distribution of degree/strength. At regional level, 4 communities are detected and members in the same regional cooperative organizations, such as EU, ASEAN, NAFTA and AU, tend to be classified into the same community, indicating that EEFN embodies the characteristics of regionalization and multi-polarization. At national level, some key economies, such as USA, China and Germany, are always at the forefront of network-based centrality measures and EEIOA-based accountings. Furthermore, the security of embodied energy supply is evaluated for each economy. Consequently, policy implications of the results are discussed, which could provide additional insights for policy formulation to enhance energy security.
A highly conductive and durable anion exchange membrane (AEM) is an essential component for alkaline electrochemical conversion and storage systems. Contrary to the conventional wisdom that the ionic ...conductivity can be improved by increasing the ion exchange capacity (IEC) through a cross-linking process, in this work, a new approach to improve the ionic conductivity by enhancing the ionic mobility is adopted. The microstructure of quaternary ammonia poly (2, 6-dimethyl-1, 4-phenylene oxide) (QAPPO) is manipulated through grafting with hydrophobic side chains, which will drive the well-established hydrophilic/hydrophobic domains and nano-phase separated, well-connected ionic channels. As a result, the local hydroxide concentration is enhanced by the novel microstructure, thereby improving the ionic conductivity of the as-prepared ionomers. The as-prepared ionomers, denoted as self-aggregated QAPPO-CF, with an intermediate IEC value achieved an ionic conductivity of 65 mS cm−1 at 80 °C, outperforming the QAPPO with an even higher IEC value. This result suggests that the microphase separation is an effective approach to enhance the ionic conductivity.
The well-established hydrophilic/hydrophobic domains and nano-phase separated, well-connected ionic channels were manipulated through grafting the hydrophobic side chains on the backbones of quaternary ammonia poly (2, 6-dimethyl-1, 4-phenylene oxide). The ionic conductivity of self-aggregated ionomers with an intermediate IEC value outperformed the traditional ionomers with an even high IEC value. Display omitted
•An effective strategy to increase hydroxide-ion conductivity was introduced.•The microstructure of ionomers was manipulated by grafting hydrophobic side chain.•Well nano-phase separated domains with connected ionic channels were established.•An ionic conductivity of 65 mS cm−1 was achieved in the self-aggregated ionomers.
There is increasing public concern about poultry welfare; the quality of animal welfare is closely related to the quality of livestock products and the health of consumers. Good animal welfare ...promotes the healthy growth of poultry, which can reduce the disease rate and improve the production quality and capacity. As behaviour responses are an important expression of welfare, the study of behaviour is a simple and non-invasive method to assess animal welfare. The use of modern technology offers the possibility to monitor the behaviour of broilers and laying hens in a continuous and automated way. This paper reviews the latest technologies used for monitoring the behaviour of broilers and laying hens under both experimental conditions and commercial applications and discusses the potential of developing a precision livestock farming (PLF) system. The techniques that are presented and discussed include sound analysis, which can be an online tool to automatically monitor poultry behaviour non-invasively at the group level; wireless, wearable sensors with radio-frequency identification devices, which can automatically identify individual chickens, track the location and movement of individuals in real time and quantify some behavioural traits accordingly and image processing technology, which can be considered a direct tool for measuring behaviours, especially activity behaviours and disease early warning. All of these technologies can monitor and analyse poultry behaviour, at the group level or individual level, on commercial farms. However, the popularity and adoption of these technologies has been hampered by the logistics of applying them to thousands and tens of thousands of birds on commercial farms. This review discusses the advantages and disadvantages of these techniques in commercial applications and presents evidence that they provide potential tools to automatically monitor the behaviours of broilers and laying hens on commercial farms. However, there still has a long way to go to develop a PLF system to detect and predict abnormal situations.
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