matlab有限元网格划分程序 DistMesh is a simple MATLAB code for GENERATION of unstructured triangular and tetrahedral meshes. It was developed by Per-Olof Persson (now at UC Berkeley) and Gilbert Strang in the Department of Mathematics at MIT. A detailed description of the program is provided in our SIAM Review paper, see documentation below. One reason that the code is short and simple is that the geometries are specified by Signed Distance Functions. These give the shortest distance from any point in space to the boundary of the domain. The sign is negative inside the region and positive outside. A simple example is the unit circle in 2-D, which has the distance function d=r-1, where r is the distance from the origin. For more complicated geometries the distance function can be computed by interpolation between values on a grid, a common representation for level set methods. For the actual mesh GENERATION, DistMesh uses the Delaunay triangulation routine in MATLAB and tries to optimize the node locations by a force-based smoothing procedure. The topology is regularly updated by Delaunay. The boundary points are only allowed to move tangentially to the boundary by projections using the distance function. This iterative procedure typically results in very well-shaped meshes. Our aim with this code is simplicity, so that everyone can understand the code and modify it according to their needs. The code is not entirely robust (that is, it might not terminate and return a well-shaped mesh), and it is relatively slow. However, our current research shows that these issues can be resolved in an optimized C++ code, and we believe our simple MATLAB code is important for demonstration of the underlying principles. To use the code, simply download it from below and run it from MATLAB. For a quick demonstration, type "meshdemo2d" or "meshdemond". For more details see the documentation.
标签： matlab有限元网格划分程序
上传时间： 2015-08-12
上传用户：凛风拂衣袖
Lithium–sulfur (Li–S) batteries with high energy density and long cycle life are considered to be one of the most promising next-GENERATION energy-storage systems beyond routine lithium-ion batteries. Various approaches have been proposed to break down technical barriers in Li–S battery systems. The use of nanostructured metal oxides and sulfides for high sulfur utilization and long life span of Li–S batteries is reviewed here. The relationships between the intrinsic properties of metal oxide/sulfide hosts and electrochemical performances of Li–S batteries are discussed. Nanostructured metal oxides/ sulfides hosts used in solid sulfur cathodes, separators/interlayers, lithium- metal-anode protection, and lithium polysulfides batteries are discussed respectively. Prospects for the future developments of Li–S batteries with nanostructured metal oxides/sulfides are also discussed.
上传时间： 2017-11-23
上传用户：653357637
3rd GENERATION Partnership Project; Technical Specification Group Radio Access Network; Further advancements for E-UTRA; LTE-Advanced feasibility studies in RAN WG4 (Release 9)
上传时间： 2018-04-28
上传用户：doforfuture
One traditional view of how wireless networks evolve is of a continuous, inevitable progres- sion to higher link speeds, combined with greater mobility over wider areas. This standpoint certainly captures the development from first and second GENERATION cellular systems focused on voice support, and the early short-range wireless data networks, through to today’s 3G cellular and mobile broadband systems; there is every confidence that the trend will continue some way into the future.
上传时间： 2020-05-26
上传用户：shancjb
Emerging technologies such as WiFi and WiMAX are profoundly changing the landscape of wireless broadband. As we evolve into future GENERATION wireless networks, a primary challenge is the support of high data rate, integrated multi- media type traffic over a unified platform. Due to its inherent advantages in high-speed communication, orthogonal frequency division multiplexing (OFDM) has become the modem of choice for a number of high profile wireless systems (e.g., DVB-T, WiFi, WiMAX, Ultra-wideband).
标签： Broadband Wireless Networks
上传时间： 2020-05-26
上传用户：shancjb
The idea of the book was born during the time when the second GENERATION cellular system was looming on the horizon.At that time ,the world was divided into three distinct camps as far as looking for a standard: Europe North America and Japan.
标签： Designing Cellular Systems Mobile Radio
上传时间： 2020-05-26
上传用户：shancjb
Today’s wireless services have come a long way since the roll out of the conventional voice-centric cellular systems. The demand for wireless access in voice and high rate data multi-media applications has been increasing. New GENERATION wireless communication systems are aimed at accommodating this demand through better resource management and improved transmission technologies.
标签： Radio Cognitive Software Defined
上传时间： 2020-05-26
上传用户：shancjb
Many times I have been asked to explain “ briefl y ” how SDH, SONET, and the OTN “ exactly ” work. The questions came mainly from new colleagues, stu- dents, and users of these technologies, personally or via the usenet newsgroup comp.dcom.sdh - sonet. I could have referred them to the standards documents, but to provide a more consistent and clear answer I decided to write this pocket guide. The objective of this book is that it can be used both as an introduction as well as a reference guide to these technologies and their spe- cifi c standards documents.
标签： GENERATION Transport Optical ComSoc Guide
上传时间： 2020-05-27
上传用户：shancjb
It is commonly accepted today that optical fiber communications have revolutionized telecommunications. Indeed, dramatic changes have been induced in the way we interact with our relatives, friends, and colleagues: we retrieve information, we entertain and educate ourselves, we buy and sell, we organize our activities, and so on, in a long list of activities. Optical fiber systems initially allowed for a significant curb in the cost of transmission and later on they sparked the process of a major rethinking regarding some, GENERATION-old, telecommunication concepts like the (OSI)-layer definition, the lack of cross-layer dependency, the oversegmentation and overfragmentation of telecommunica- tions networks, and so on.
上传时间： 2020-05-27
上传用户：shancjb
The next-GENERATION wireless broadband technology is changing the way we work, live, learn, and communicate through effective use of state- of-the-art mobile broadband technology. The packet-data-based revolu- tion started around 2000 with the introduction of 1x Evolved Data Only (1xEV-DO) and 1x Evolved Data Voice (1xEV-DV) in 3GPP2 and High Speed Downlink Packet Access (HSDPA) in 3GPP. The wireless broad- band fourth-GENERATION technology (4G) is an evolution of the packet- based 3G system and provides a comprehensive evolution of the Universal Mobile Telecommunications System specifications so as to remain competitive with other broadband systems such as 802.16e (WiMAX)
标签： Essentials LTE-A LTE and of
上传时间： 2020-05-27
上传用户：shancjb
