function [alpha,N,U]=youxianchafen2(r1,r2,up,under,num,deta) %[alpha,N,U]=youxianchafen2(a,r1,r2,up,under,num,deta) %该函数用有限差分法求解有两种介质的正方形区域的二维拉普拉斯方程的数值解 %函数返回迭代因子、迭代次数以及迭代完成后所求区域内网格节点处的值 %a为正方形求解区域的边长 %r1,r2分别表示两种介质的电导率 %up,under分别为上下边界值 %num表示将区域每边的网格剖分个数 %deta为迭代过程中所允许的相对误差限 n=num+1; %每边节点数 U(n,n)=0; %节点处数值矩阵 N=0; %迭代次数初值 alpha=2/(1+sin(pi/num));%超松弛迭代因子 k=r1/r2; %两介质电导率之比 U(1,1:n)=up; %求解区域上边界第一类边界条件 U(n,1:n)=under; %求解区域下边界第一类边界条件 U(2:num,1)=0;U(2:num,n)=0; for i=2:num U(i,2:num)=up-(up-under)/num*(i-1);%采用线性赋值对上下边界之间的节点赋迭代初值 end G=1; while G>0 %迭代条件：不满足相对误差限要求的节点数目G不为零 Un=U; %完成第n次迭代后所有节点处的值 G=0; %每完成一次迭代将不满足相对误差限要求的节点数目归零 for j=1:n for i=2:num U1=U(i,j); %第n次迭代时网格节点处的值 if j==1 %第n+1次迭代左边界第二类边界条件 U(i,j)=1/4*(2*U(i,j+1)+U(i-1,j)+U(i+1,j)); end if (j>1)&&(j U2=1/4*(U(i,j+1)+ U(i-1,j)+ U(i,j-1)+ U(i+1,j)); U(i,j)=U1+alpha*(U2-U1); %引入超松弛迭代因子后的网格节点处的值 end if i==n+1-j %第n+1次迭代两介质分界面（与网格对角线重合）第二类边界条件 U(i,j)=1/4*(2/(1+k)*(U(i,j+1)+U(i+1,j))+2*k/(1+k)*(U(i-1,j)+U(i,j-1))); end if j==n %第n+1次迭代右边界第二类边界条件 U(i,n)=1/4*(2*U(i,j-1)+U(i-1,j)+U(i+1,j)); end end end N=N+1 %显示迭代次数 Un1=U; %完成第n+1次迭代后所有节点处的值 err=abs((Un1-Un)./Un1);%第n+1次迭代与第n次迭代所有节点值的相对误差 err(1,1:n)=0; %上边界节点相对误差置零 err(n,1:n)=0; %下边界节点相对误差置零 G=sum(sum(err>deta))%显示每次迭代后不满足相对误差限要求的节点数目G end
标签： 有限差分
上传时间： 2018-07-13
上传用户：Kemin
Microsoft Visual Studio Solution File, Format Version 9.00 # Visual Studio 2005
标签： 游戏
上传时间： 2019-07-19
上传用户：cmpcmp
AO4420, AO4420L ( Green Product ) N-Channel Enhancement Mode Field Effect Transistor
上传时间： 2020-04-19
上传用户：su1254
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.
标签： Technology Cellular Radio 3GPP LTE and
上传时间： 2020-05-26
上传用户：shancjb
This book describes the applications of the fundamental interactions of electromagnetic waves and materials as described in the preceding volume, “Basic Electromagnetism and Materials”. It is addressed to students studying masters or doctorate courses in electronics, electromagnetism, applied physics, materials physics, or chemical physics. In particular, this volume analyzes the behavior of materials in the presence of an electromagnetic field and related applications in the fields of electronics, optics, and materials physics.
标签： Electromagnetism Materials Applied and
上传时间： 2020-05-26
上传用户：shancjb
A series of features makes the mobile telecommunications industry an interesting field of investigation for economists: the industry is experi- encing veryfastmarketgrowthcombinedwithrapidtechnological change; regulatory design in setting market structure is playing a very important role; and oligopolistic competition is unfolding under various forms. The number of subscribers to mobile networks is growing at a rapid rate on a worldwide basis, as shown in figure 1.1.
标签： Telecommunications Economics Mobile of
上传时间： 2020-05-27
上传用户：shancjb
The field of digital communication has evolved rapidly in the past few decades, with commercial applications proliferating in wireline communi- cation networks (e.g., digital subscriber loop, cable, fiber optics), wireless communication (e.g., cell phones and wireless local area networks), and stor- age media (e.g., compact discs, hard drives). The typical undergraduate and graduate student is drawn to the field because of these applications, but is often intimidated by the mathematical background necessary to understand communication theory.
标签： Communication Fundamentals Digital of
上传时间： 2020-05-27
上传用户：shancjb
The writing of this book was prompted by two main developments in wireless communications in the past decade. First is the huge surge of research activities in physical-layer wireless communication theory. While this has been a subject of study since the 60’s, recent developments in the field, such as opportunistic and multi-input multi-output (MIMO) communication techniques, have brought completely new per- spectives on how to communicate over wireless channels.
标签： Communication Fundamentals Wireless of
上传时间： 2020-05-27
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
Since the principle of multi-carrier code division multiple access (MC-CDMA) was simultaneously proposed by Khaled Fazel et al. and Nathan Yee et al. at the IEEE International Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC) in the year 1993, multi-carrier spread spectrum (MC-SS) has rapidly become one of the most wide spread independent research topics on the field of mobile radio communications. Therefore, the International Workshop on Multi-Carrier Spread Spectrum (MC-SS) was initiated in the year 1997. Multi-carrier and spread spectrum systems with their generic air interface and adaptive technologies are considered as potential candidates to fulfill the requirements of next generation mobile communications systems.
标签： Multi-Carrier Spectrum Spread 2007
上传时间： 2020-05-31
上传用户：shancjb
