Lithium–sulfur batteries are a promising energy-storage technology due to their relatively low cost and high theoretical energy density. However, one of their major technical problems is the shuttling of soluble polysulfides between electrodes, resulting in rapid capacity fading. Here, we present a metal–organic framework (MOF)-based battery separator to mitigate the shuttling problem. We show that the MOF-based separator acts as an ionic sieve in lithium–sulfur batteries, which selectively sieves Li+ ions while e ciently suppressing undesired polysulfides migrating to the anode side. When a sulfur-containing mesoporous carbon material (approximately 70 wt% sulfur content) is used as a cathode composite without elaborate synthesis or surface modification, a lithium–sulfur battery with a MOF-based separator exhibits a low capacity decay rate (0.019% per cycle over 1,500 cycles). Moreover, there is almost no capacity fading after the initial 100 cycles. Our approach demonstrates the potential for MOF-based materials as separators for energy-storage applications.
上传时间： 2017-11-23
上传用户：653357637
The SP2526A device is a dual +3.0V to +5.5V USB Supervisory Power Control Switch ideal for self-powered and bus-powered Universal Serial Bus (USB) applications. Each switch has low on-resistance (110mΩ typical) and can supply 500mA minimum. The fault currents are limited to 1.0A typical and the flag output pin for each switch is available to indicate fault conditions to the USB controller. The thermal shutdown feature will prevent damage to the device when subjected to excessive current loads. The undervoltage lockout feature will ensure that the device will remain off unless there is a valid input voltage present.
标签： High-Side Switch Power Dual USB
上传时间： 2019-03-06
上传用户：bhitr
In this paper we present a classifier called bi-density twin support vector machines (BDTWSVMs) for data classification. In the training stage, BDTWSVMs first compute the relative density degrees for all training points using the intra-class graph whose weights are determined by a local scaling heuristic strategy, then optimize a pair of nonparallel hyperplanes through two smaller sized support vector machine (SVM)-typed problems. In the prediction stage, BDTWSVMs assign to the class label depending on the kernel density degree-based distances from each test point to the two hyperplanes. BDTWSVMs not only inherit good properties from twin support vector machines (TWSVMs) but also give good description for data points. The experimental results on toy as well as publicly available datasets indicate that BDTWSVMs compare favorably with classical SVMs and TWSVMs in terms of generalization
标签： recognition Bi-density machines support pattern vector twin for
上传时间： 2019-06-09
上传用户：lyaiqing
Communication between various devices makes it possible to pro- vide unique and innovative services. Although this interdevice com- munication is a very powerful mechanism, it is also a complex and clumsy mechanism, leading to a lot of complexity in present day systems. This not only makes networking difficult but also limits its flexibility.
标签： Wireless Networks Mobile Hoc Ad
上传时间： 2020-05-26
上传用户：shancjb
At present, there is a strong worldwide push toward bringing fiber closer to indi- vidual homes and businesses. Fiber-to-the-Home/Business (FTTH/B) or close to it networks are poised to become the next major success story for optical fiber com- munications. In fact, FTTH connections are currently experiencing double-digit or even higher growth rates, e.g., in the United States the annual growth rate was 112% between September 2006 and September 2007, and their presence can add value of U.S. $4,000–15,000 to the selling price of a home.
标签： Technologies Broadband Networks Access
上传时间： 2020-05-26
上传用户：shancjb
The aim of this book, the first of two volumes, is to present selected research that has been undertaken under COST Action IC0902 ‘‘Cognitive Radio and Net- working for Cooperative Coexistence of Heterogeneous Wireless Networks’’ (http://newyork.ing.uniroma1.it/IC0902/). COST (European Cooperation in Sci- ence and Technology) is one of the longest-running European frameworks sup- porting cooperation among scientists and researchers across Europe.
上传时间： 2020-05-26
上传用户：shancjb
This book is the outcome of the panel discussions held on the special event honor- ing first 50 PhD students of Prof. Ramjee Prasad. Several of his PhD students are today worldwide telecommunication leaders themselves. Over 60 post-docs, PhDs, colleagues and the scientific staff were present at the event to celebrate the research and development achievements in the field of mobile and wireless communication.
标签： Globalization Mobile of
上传时间： 2020-05-27
上传用户：shancjb
Thisbookfocusesontheemergingresearchtopic‘green(energy-efficient)wirelessnetworks’ that has drawn huge attention recently from both academia and industry. This topic is highly motivated due to important environmental, financial and quality-of-experience (QoE) consid- erations.Duetosuchconcerns,varioussolutionshavebeenproposedtoenableefficientenergy usage in wireless networks, and these approaches are referred to as green wireless communi- cations and networking. The term ‘green’ emphasizes the environmental dimension of the proposed solutions. Hence, it is not sufficient to present a cost-effective solution unless it is eco-friendly.
标签： Green_Heterogeneous_Wireless_Netw orks
上传时间： 2020-05-27
上传用户：shancjb
Wireless is one of the most rapidly developing technologies in our time, with dazzling new products and services emerging on an almost daily basis. These developments present enormous challenges for communications engineers, as the demand for increased wireless capacity grows explosively. Indeed, the discipline of wireless communications presents many challenges to designers that arise as a result of the demanding nature of the physical medium and the complexities in the dynamics of the underlying network.
标签： Communications Wireless MIMO
上传时间： 2020-05-28
上传用户：shancjb
With this book at your fingertips, you, the reader, and I have something in common. We share the same interest in mobile radio channels. This area attracted my interest first in autumn 1992 whenImovedfromindustrytoacademiatofindachallengeinmylifeandtopursueascientific career. Since then, I consider myself as a student of the mobile radio channel who lives for modelling, analyzing, and simulating them. While the first edition of this book resulted from my teaching and research activities at the Technical University of Hamburg-Harburg (TUHH), Germany, the present second edition is entirely an outcome of my work at the University of Agder, Norway.
上传时间： 2020-05-30
上传用户：shancjb
