T*********r
发帖数: 11175 | 1 最坏情况就直接caption的text里面$Y=a+b X+e_t$呗
你在figure caption里放equation
格式会比较奇怪
in |
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T*******n
发帖数: 493 | 2 Show your code for the equation(s), and where you want
to add space. |
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h*****g
发帖数: 944 | 3 用了
\begin{align}
\end{align}
结果equation全部都向右对齐，如何向左对齐？ |
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S*****n
发帖数: 6055 | 4 when using the Scherrer Equation, how to choose the shape factor K?
I've seen papers using 0.8, 0.9, 1.0. How to appropriately choose it? Or
people just randomly use something?
Thanks! |
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c*********n
发帖数: 5 | 5 有没有什么介绍elaticity equation及其数值解的英文资料？
thanks |
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p******n
发帖数: 66 | 6 Does any expert here know where I can find a C package for
solving one-variable polynomial equation?
Thanks a lot!bow! |
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t****n
发帖数: 39 | 7 Any one has experience of solving a linear equation system with
block tridiagonal matrix? I really need a fast solver. Currently
I'm using Gauss elimination method. |
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g*******u
发帖数: 5 | 8 If the governing equation is like Poisson or linear
elasticity, you can use Fast-Multipole Expansion method,
which gives you a N*log(N) complexity, else you probably
have to live with N^2. |
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o****l
发帖数: 21 | 9 I think you'd better post your integral equation and boundary
conditions so that people can think about your question more
efficiently and specifically. |
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b*****g
发帖数: 38 | 10 I have an equation:
dz/dt = (1-z)-S(t)z
How to solve it using MATLAB?
Seems pretty easy, but I can't get the correct wave shape. So frastrated.
Anyone can help me. Thank you. |
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l******g
发帖数: 3 | 11 在用NDSolve解DE的时候, 那本厚厚的手册里给出一些参数选项, 比如: AccuracyGoal,
PrecisionGoal, MaxSteps, StartingStepSize, MaxStepSize.
我在用NDSolve求解一个Time Dependent Defferential Equation, 需要对MaxSteps和
StartingStepSize选择合适的值才能给出正确的结果. 但是我不理解MaxSteps,
StartingStepSize的含义和他们之间的关系. 因此总是做不对. 恳请各位高手帮我,
不胜感激 |
|
o*l
发帖数: 3022 | 12 what is St. Venant's differential equations?
thanks |
|
x******r
发帖数: 367 | 13 Are there any softwares that can solve Poisson equation numerically
directly,matlab, mathematica or others?
I mean that it will give you the result without writing code by yourself? |
|
m***u
发帖数: 88 | 14 各位前辈，
对于任何一个二阶微分方程如Schrodinger equation,如何用MATHEMATICA数值求解它们
的本征值(一维或三维的)？多谢了：if you have, please send it to
d*****[email protected] |
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w***h
发帖数: 415 | 15 手头有一本电子书(1.5M), 需要者留下收件的电邮.
手续费两个包子(20买卖提伪币), 以表示对鄙人的感谢, 呵呵.
电子书信息:
Texts in Applied Mathematics 45
Stig Larsson · Vidar Thomée
"Partial Differential Equations with Numerical Methods"
First softcover printing 2009
ISBN 978-3-540-88705-8 e-ISBN 978-3-540-88706-5
DOI 10.1007/978-3-540-88706-5
Texts in Applied Mathematics ISSN 0939-2475
Library of Congress Control Number: 2008940064
Mathematics Subject Classification (2000): 35-01, 65-01
2009, 2003 Springer-Verlag Berlin Heidelberg |
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m********5
发帖数: 619 | 16 各位大牛
有没有可能做一个3-stage equation
the first stage's dep var is dummy variable
the second and third stage's dep vars are continuous variables
谢谢!
送双黄包 |
|
p******e
发帖数: 136 | 17 找本书把stochastic control theory仔细看下，把state and control variable 的意
义弄明白，然后要根据自己研究的东西，写differential equation,,别人整部明白你
想表达的是什么 |
|
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a*********n
发帖数: 1331 | 19 想要知道到底哪些factors使得被暂时释放的罪犯回来。但是这里面有很大的selection
bias，就是被释放的都是罪轻的，重罪的都不可能释放，所以这里有selection bias
的问题。factors有50多个比如犯的什么罪、工作情况等。
如果不用Heckman two-step做，用Simultaneous equations model怎么做？
或者其他方法？ |
|
a*********n
发帖数: 1331 | 20 因为Heckman two-step有assumption的问题，所以转而想用其它能避开sample
selection bias问题的方法做。
2SLS不妥？
那simultaneous equations model呢？ |
|
a*********n
发帖数: 1331 | 21 知道了，2SLS不能做。改了标题。
用simultaneous equations model怎么做？ |
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f***5
发帖数: 1569 | 22 heckman should work, I haven't seen any body use simultaneous equations to
solve selection issue. |
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d********g
发帖数: 2 | 23 假设我有impulse response, 想做curve fitting，求出difference equation, 有办法
吗?
多谢。 |
|
r****r
发帖数: 306 | 24 Close-form will be better.
Besides, how to use Matlab to solve the equations set? |
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z*****n
发帖数: 7639 | 25
we
system,
human
This is exactly the point I was doubting in previous post.
Human socity is a very complex system and many
behaviours cannot be modeled. Engineering
(including auto-control) needs strict math model.
So I call this using differential equation/laplas transform
thing in economics is a kind of 忽悠。
anyone |
|
w***h
发帖数: 415 | 26 手头有一本电子书(1.5M), 需要者留下收件的电邮.
手续费两个包子(20买卖提伪币), 以表示对鄙人的感谢, 呵呵.
电子书信息:
Texts in Applied Mathematics 45
Stig Larsson · Vidar Thomée
"Partial Differential Equations with Numerical Methods"
First softcover printing 2009
ISBN 978-3-540-88705-8 e-ISBN 978-3-540-88706-5
DOI 10.1007/978-3-540-88706-5
Texts in Applied Mathematics ISSN 0939-2475
Library of Congress Control Number: 2008940064
Mathematics Subject Classification (2000): 35-01, 65-01
2009, 2003 Springer-Verlag Berlin Heidelberg |
|
w********h
发帖数: 12367 | 27 【 以下文字转载自 Chemistry 讨论区,原文如下 】
发信人: wonderlich (左岸，遁去), 信区: Chemistry
标 题: Re: Help, who knows the equation to calculate Rg of PPO?
发信站: The unknown SPACE (Thu Jun 20 01:06:40 2002) WWW-POST
what's PPO?
you can check Fetters' review paper on Macromolecules in 1994.
Fetters, L. J.; Lohse, D. J.; Richter, D.; et al.
Macromolecules 1994, 27, 4639.
I think you can find the values for /Mw,
and then you can calculate Rg from the product of /Mw and Mw.
You can search on web to see the valu |
|
x*****m
发帖数: 12 | 28 I just heard it for the first time this morning
Weinan E and some other mathematicans held a workshop
on multiscale modelling of complex fluids at PKU today
The mathematicans are so terrible because they made
so many equations
how to derive it? |
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w********h
发帖数: 12367 | 29 that estimate is too rough...Fox equation: 1/Tg = M1/Tg1 + M2/Tg2.
You have to consider those two polymers have molecular weight dependence of
Tg. |
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c******h
发帖数: 4573 | 30 fox equation是经验公式
不是对每个copolymer都适用
根据你的polymer结构，选用带双检测器的SEC估计能检测第二个block的分子量。 |
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c******h
发帖数: 4573 | 31 NMR先看看两段的mole fraction
Fox Equation的话是weight fraction
假定一个相当的重量的polymer，已知三个Tg，两个mol% 其中一段的分子量，应该可以
计算吧？不过都是大大的近似值了。 |
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c********r
发帖数: 2227 | 32 我觉得不行啊....
在给第一个大牛的回帖里说了一下
NMR先看看两段的mole fraction
Fox Equation的话是weight fraction
假定一个相当的重量的polymer，已知三个Tg，两个mol% 其中一段的分子量，应该可以
计算吧？不过都是大大的近似值了。 |
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s******8
发帖数: 292 | 33 我觉得老板的意思应该是要你用Fox equation去计算hard segment 和soft segment在
Block copolymer中的weight percent，然后跟投料比做比较吧，看是不是跟投料比
match。 |
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A****n
发帖数: 241 | 34 大家好！小女子弱问一个公式应用的问题。
用Korsmeyer-Peppas equation 来研究diffusion mechanism的时候，为什么n<=0.5就
可以说是Fickian diffusion了呢？看到无数用这个标准的文章没讲出处，也查到了书
上讲这个的章节，但是查不到为什么会有这样的标准，没找到原始的资料，这个0.5从
哪里来的呢? 不知道该往哪里找这个答案，请版上大牛赐教。
感激不尽！ |
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D********g
发帖数: 533 | 35 解Fickian diffusion equation得出的理论值 |
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a***n
发帖数: 202 | 36 how to solve the difference equation:
X(t+1)=aX(t)-bX(t)^2, where a and b are positive.
How to get the steady state and the time path?
3x! |
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n***s
发帖数: 1257 | 37 one dimentional wave equation:
d2(u)/dt2=c2*d2(u)/dx2 (1)
Initial conditions:
u(x,0)=0, du/dt(x,0)=0 (2)
Boundary condition:
u(x,t)=g(t), x=t*c/2 (c>0) (3)
我想,满足 (1) and (2) 的解只有 u(x,t)=0,
但还有一个边界条件.
到底该如何解才对呢
Thank you! |
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m****n
发帖数: 45 | 38
this equation can be converted to dx=dy/sqrt(c/y-1)
integrate both sides |
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L*M
发帖数: 8 | 39 Anyone who has Mathematica or maple, lease help me solve following equations:
(Yc-Y0)**2 + (Xc-X0)**2 = r**2
(Y1-Y0)**2 + (X1-X0)**2 = (r-r1)**2
(Y2-Y0)**2 + (X2-X0)**2 = (r-r2)**2
r, X0, Y0 are variables. r1, r2, X1, Y1, X2, Y2, Xc, Yc are paremeters.
TIA |
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b*******n
发帖数: 5065 | 40
equations:
find the co-center?
it is too messy to post.
if given parameters, then simple form.
|
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L*M
发帖数: 8 | 41 are you kidding me????
What's the "_Z" in the solution? I do not have _Z in my equation.
Did you make a mistake, or a typo???
^2
^2
r2^
2*
Xc^
4+
2* |
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b*******n
发帖数: 5065 | 42
arcs
your equations are not the solution to your problem then.
think it again.
don't just beg for solution. |
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L*M
发帖数: 8 | 43 Anyone who has Mathematica, maple, or other tools, lease help me solve
following equations:
(Yc-Y0)**2 + (Xc-X0)**2 = r**2
(Y1-Y0)**2 + (X1-X0)**2 = (r-r1)**2
(Y2-Y0)**2 + (X2-X0)**2 = (r-r2)**2
r, X0, Y0 are variables. r1, r2, X1, Y1, X2, Y2, Xc, Yc are paremeters. |
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l******n
发帖数: 9344 | 44 一个distribution function defined as:
phi: [0,T]*Omega*S^2 ----> Omega
Omega is a domain in R^n.(you can take n=3)
phi satisfies the following equation
dphi/dt + (v*\nabla)phi=\Delta phi + \nabla \cdot (g*phi)
v is H^1 in Omega, the first \nabla is direvatives to variables in Omega
, the second \nabla is direvatves to variables in S^2, g is a smooth fun
ction on S^2.
initially phi is smooth, has anybody any idea how to prove that phi is H
^1(Omega) or L^2(Omega)?
Or if you know any papers related, |
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j**p
发帖数: 53 | 45 hi friends, I was just wondering whether there is a name for the following
system of algebraic equations (must have been extensively studied I assume)
\sum_{i=1}^K n_i = N_1
\sum_{i=1}^K {n_i}^2 = N_2
essentially we are looking for integer solutions on the intersection of a
hyper-sphere and a hyperplane in K-dimensions.
Many thanks! |
|
t*****k
发帖数: 390 | 46 对于advection equation, u_t + au_x = 0, if a is very large, whether this sys
tem is stiff or not? 是否一定要用implicit method 来做. Thanks! |
|
m***l
发帖数: 267 | 47 【 以下文字转载自 Computation 讨论区 】
发信人: moral (moral), 信区: Computation
标 题: Any quick solution for this equation in Matlab?
发信站: BBS 未名空间站 (Mon Mar 8 18:46:15 2010, 美东)
X and Y are function of x and t. Thanks |
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d********n
发帖数: 34 | 48 请问谁有Ikeda的Stochastic Differential Equations and Diffusion Processes吗？
这本书out of print了，图书馆的又很抢手。谢啦~ |
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l********e
发帖数: 3632 | 49 重新安装-》修改安装 里面有选项，可以选择equation. |
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r**q
发帖数: 251 | 50 The monge-ampere equation,Cristian E. Gutiérrez
哪位大虾有啊？ |
|
