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991.
Mingbo Zheng Hao Tang Qin Hu Shasha Zheng Lulu Li Jing Xu Huan Pang 《Advanced functional materials》2018,28(20)
Lithium‐ion batteries are widely used as reliable electrochemical energy storage devices due to their high energy density and excellent cycling performance. The search for anode materials with excellent electrochemical performances remains critical to the further development of lithium‐ion batteries. Tungsten‐based materials are receiving considerable attention as promising anode materials for lithium‐ion batteries owing to their high intrinsic density and rich framework diversity. This review describes the advances of exploratory research on tungsten‐based materials (tungsten oxide, tungsten sulfide, tungsten diselenide, and their composites) in lithium‐ion batteries, including synthesis methods, microstructures, and electrochemical performance. Some personal prospects for the further development of this field are also proposed. 相似文献
992.
Efficient Charge Injection in Organic Field‐Effect Transistors Enabled by Low‐Temperature Atomic Layer Deposition of Ultrathin VOx Interlayer 下载免费PDF全文
Yuanhong Gao Youdong Shao Lijia Yan Hao Li Yantao Su Hong Meng Xinwei Wang 《Advanced functional materials》2016,26(25):4456-4463
Charge injection at metal/organic interface is a critical issue for organic electronic devices in general as poor charge injection would cause high contact resistance and severely limit the performance of organic devices. In this work, a new approach is presented to enhance the charge injection by using atomic layer deposition (ALD) to prepare an ultrathin vanadium oxide (VOx) layer as an efficient hole injection interlayer for organic field‐effect transistors (OFETs). Since organic materials are generally delicate, a gentle low‐temperature ALD process is necessary for compatibility. Therefore, a new low‐temperature ALD process is developed for VOx at 50 °C using a highly volatile vanadium precursor of tetrakis(dimethylamino)vanadium and non‐oxidizing water as the oxygen source. The process is able to prepare highly smooth, uniform, and conformal VOx thin films with precise control of film thickness. With this ALD process, it is further demonstrated that the ALD VOx interlayer is able to remarkably reduce the interface contact resistance, and, therefore, significantly enhance the device performance of OFETs. Multiple combinations of the metal/VOx/organic interface (i.e., Cu/VOx/pentacene, Au/VOx/pentacene, and Au/VOx/BOPAnt) are examined, and the results uniformly show the effectiveness of reducing the contact resistance in all cases, which, therefore, highlights the broad promise of this ALD approach for organic devices applications in general. 相似文献
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994.
随着互联网门户网站的崛起,以及人们在选购商品时对于互联网的依赖,人们往往会在选购商品前在网络上查找商品的评价信息。但是面对海量的评论信息,感觉无从下手,需要一种能够自动识别评价语句情感倾向性的方法。针对这种情况,陈豪,刘功申等人选定酒店、笔记本电脑、书籍这3种商品,根据商品的特殊性,提出一种基于句法分析的商品情感倾向性分析算法,这种算法的创新之处在于利用句法分析的方法获得评价对象集,并且对评价对象进行权值的分配,再利用依赖关系找到并且处理从句,以及隐含的评价对象,最后得出整句评价语句的正负面评价结果。 相似文献
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997.
A broadband frequency doubler using left-handed nonlinear transmission lines(LH NLTLs) based on MMIC technology is reported for the first time.The second harmonic generation on LH NLTLs was analyzed theoretically. A four-section LH NLTL which has a layout of 5.4×0.8 mm~2 was fabricated on GaAs semi-insulating substrate. With 20-dBm input power,the doubler obtained 6.33 dBm peak output power at 26.8 GHz with 24-43 GHz—6 dBm bandwidth.The experimental results were quite consistent with the simulated results.The compactness and the broad band characteristics of the circuit make it well suit for GaAs RF/MMIC application. 相似文献
998.
本文主要介绍了差压变送器的工作原理、常用的三种测量应用方式、主要安装方法及注意事项,直观判断法、仪表检测法诊断差压变送器测量回路的应用故障,并重点对导压管堵塞、泄漏,平衡泄漏、气体流量测量导压管积液等问题引起的故障现象进行了重点分析. 相似文献
999.
Nitrogen‐Doped Graphene Ribbon Assembled Core–Sheath MnO@Graphene Scrolls as Hierarchically Ordered 3D Porous Electrodes for Fast and Durable Lithium Storage 下载免费PDF全文
Yun Zhang Penghui Chen Xu Gao Bo Wang Heng Liu Hao Wu Huakun Liu Shixue Dou 《Advanced functional materials》2016,26(43):7754-7765
Graphene scroll is an emerging 1D tubular form of graphitic carbon that has potential applications in electrochemical energy storage. However, it still remains a challenge to composite graphene scrolls with other nanomaterials for building advanced electrode configuration with fast and durable lithium storage properties. Here, a transition‐metal‐oxide‐based hierarchically ordered 3D porous electrode is designed based on assembling 1D core–sheath MnO@N‐doped graphene scrolls with 2D N‐doped graphene ribbons. In the resulting architecture, porous MnO nanowires confined in tubular graphene scrolls are mechanically isolated but electronically well‐connected, while the interwoven graphene ribbons offer continuous conductive paths for electron transfer in all directions. Moreover, the elastic graphene scrolls together with enough internal voids are able to accommodate the volume expansion of the enclosed MnO. Because of these merits, the as‐built electrode manifests ultrahigh rate capability (349 mAh g?1 at 8.0 A g?1; 205 mAh g?1 at 15.0 A g?1) and robust cycling stability (812 mAh g?1 remaining after 1000 cycles at 2.0 A g?1) and is the most efficient MnO‐based anode ever reported for lithium‐ion batteries. This unique multidimensional and hierarchically ordered structure design is believed to hold great potential in generalizable synthesis of graphene scrolls composited with oxide nanowires for mutifuctional energy storage. 相似文献
1000.