-
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.
標簽：
鋰硫電池
隔膜
上傳時間：
2017-11-23
上傳用戶：653357637
-
壓縮包中有5篇論文，分別為《Data-driven analysis of variables and dependencies in continuous optimization problems and EDAs》這是一篇博士論文，較為詳細的介紹了各種EDA算法；《Anisotropic adaptive variance scaling for Gaussian estimation of distribution algorithm》《Enhancing Gaussian Estimation of Distribution Algorithm by Exploiting Evolution Direction with Archive》《Niching an Archive-based Gaussian Estimation of Distribution Algorithm via Adaptive Clustering》《Supplementary material for Enhancing Gaussian Estimation of Distribution Algorithm by Exploiting Evolution Direction with Archive》《基于一般二階混合矩的高斯分布估計算法》介紹了一些基于EDA的創(chuàng)新算法。
標簽：
EDA
分布估計算法
論文
上傳時間：
2020-05-25
上傳用戶：duwenhao
-
This book provides technical information about all aspects of 3GPP LTE. The areas
covered range from basic concepts to research-grade material, including future
directions. The book captures the current state of 3GPP LTE technology and serves
as a source of comprehensive reference material on this subject. It has a total of
12 chapters authored by 50 experts from around the world. The targeted audi-
ence includes professionals who are designers or planners for 3GPP LTE systems,
researchers (faculty members and graduate students), and those who would like to
learn about this field.
標簽：
Technology
Cellular
Radio
3GPP
LTE
and
上傳時間：
2020-05-26
上傳用戶：shancjb
-
This book is an entry-level text on the technology of telecommunications. It has been
crafted with the newcomer in mind. The twenty-one chapters of text have been prepared
for high-school graduates who understand algebra, logarithms, and the basic principles of
electricity such as Ohm’s law. However, it is appreciated that many readers require support
in these areas. Appendices A and B review the essentials of electricity and mathematics
up through logarithms. This material was placed in the appendices so as not to distract
from the main theme, the technology of telecommunication systems. Another topic that
many in the industry find difficult is the use of decibels and derived units. Appendix C
provides the reader a basic understanding of decibels and their applications. The only
mathematics necessary is an understanding of the powers of ten
標簽：
Telecommunications
Fundamentals
2nd
of
ed
上傳時間：
2020-05-27
上傳用戶：shancjb
-
This book is intended for RF planners, to serve as a practical tool in their daily work
designing indoor radio distribution systems.
Based on feedback from readers of the first edition it was clear to me that I needed to add
more material and in depth description of the basics of indoor systems based on using
repeaters; this has grown into a new Section 4.7.
There was also a strong demand to add more detail and dedicate a full chapter to radio
planning in tunnels, for both rail and road tunnels; and redundancy principles in the design
focus for solving the challenge of handover zones. An entire Chapter 11 is now dedicated to
tunnel radio planning.
標簽：
Planning
Indoor
Radio
上傳時間：
2020-05-27
上傳用戶：shancjb
-
This books presents the research work of COST 273 Towards Mobile Broadband Multimedia
Networks, hence, it reports on the work performed and on the results achieved within the project
by its participants. The material presented here corresponds to the results obtained in four years
of collaborative work by more than 350 researchers from 137 institutions (universities, operators,
manufacturers, regulators, independent laboratories and others – a full list is provided in Appendix
B) belonging to 29 countries (mainly European, but also from Asia and North America) in the area of
mobileradio. Theobjectiveofpublishingtheseresultsasabookisessentiallytomakethemavailable
to an audience wider than the project. In fact, it just follows a ‘tradition’ of previous COST Actions
in this area of telecommunications, i.e. COST 207, 231 and 259.
標簽：
Multimedia
Techniques
Broadband
Networks
Mobile
上傳時間：
2020-05-30
上傳用戶：shancjb
-
Before delving into the details of orthogonal frequency division multiplexing (OFDM), relevant
background material must be presented first. The purpose of this chapter is to provide the necessary
building blocks for the development of OFDM principles. Included in this chapter are reviews of stochastic
and random process, discrete-time signals and systems, and the Discrete Fourier Transform (DFT). Tooled
with the necessary mathematical foundation, we proceed with an overview of digital communication
systems and OFDM communication systems. We conclude the chapter with summaries of the OFDM
wireless LAN standards currently in existence and a high-level comparison of single carrier systems versus
OFDM.
標簽：
Wireless
OFDM
LANS
上傳時間：
2020-05-31
上傳用戶：shancjb
-
The continuing vitality of spread-spectrum communication systems and the devel-
opment of new mathematical methods for their analysis provided the motivation to
undertake this new edition of the book. This edition is intended to enable readers
to understand the current state-of-the-art in this field. Almost twenty percent of the
materialinthiseditionisnew, includingseveralnewsections, anewchapteronadap-
tive arrays and filters, and a new chapter on code-division multiple-access networks.
The remainder of the material has been thoroughly revised, and I have removed a
considerable amount of material that has been superseded by more definitive results.
標簽：
Spread-Spectrum
Communication
Systems
3rd
上傳時間：
2020-06-01
上傳用戶：shancjb
-
The idea for this book was born during one of my project-related trips to the beautiful city
of Hangzhou in China, where in the role of Chief Architect I had to guide a team of very
young, very smart and extremely dedicated software developers and verification engineers.
Soon it became clear that as eager as the team was to jump into the coding, it did not have
any experience in system architecture and design and if I did not want to spend all my time in
constant travel between San Francisco and Hangzhou, the only option was to groom a number
of local junior architects. Logically, one of the first questions being asked by these carefully
selected future architects was whether I could recommend a book or other learning material
that could speed up the learning cycle. I could not. Of course, there were many books on
various related topics, but many of them were too old and most of the updated information
was either somewhere on the Internet dispersed between many sites and online magazines, or
buried in my brain along with many years of experience of system architecture.
標簽：
Telecommunication
Gateways
System
Design
for
上傳時間：
2020-06-01
上傳用戶：shancjb
-
Dear Reader, this book project brings to you a unique study tool for ESD
protection solutions used in analog-integrated circuit (IC) design. Quick-start
learning is combined with in-depth understanding for the whole spectrum of cross-
disciplinary knowledge required to excel in the ESD field. The chapters cover
technical material from elementary semiconductor structure and device levels up
to complex analog circuit design examples and case studies.
標簽：
Circuits
Design
Analog
ESD
for
上傳時間：
2020-06-05
上傳用戶：shancjb
