S*****n
发帖数: 6055 | 1 【 以下文字转载自 Chemistry 讨论区 】
发信人: Synthon (合成子·生命中的一点缠结), 信区: Chemistry
标 题: Question on Scherrer Equation (with baozi)
发信站: BBS 未名空间站 (Tue Apr 10 12:22:09 2012, 美东)
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! |
|
g****r
发帖数: 2 | 2 Hi, I'd like to solve a very simple second order differnetial
equation. Anyone can help me to get the solution?
The equation is like follows:
d^2[x(t)] |
|
j******i
发帖数: 6 | 3 To anybody who knows black-scholes model and stochastic differential
equation or anybody who knows control theory.
dS=αSdt+βSdB, S denote the price of a stock depends on S(t), α is the
drift or rate of return, β is the volatility, B is brownian motion.
How do I incorporate the control parameter γ , and a number “ L “defined
as dN/dS, where N denotes the amount of asset traded and S denote the asset
price so that dS=(αS+γ/L)dt+βSdB
defines a differential equation.
Thank you in advance |
|
j******i
发帖数: 6 | 4 To anybody who knows black-scholes model and stochastic differential
equation or anybody who knows control theory.
dS=αSdt+βSdB, S denote the price of a stock depends on t,S(t), α is the
drift or rate of return, β is the volatility, B is brownian motion.
How do I incorporate the control parameter γ , and a number “ L “defined
as dN/dS, where N denotes the amount of asset traded and S denote the asset
price so that dS=(αS+γ/L)dt+βSdB
defines a differential equation.
Thank you in advance |
|
w**a
发帖数: 1024 | 5 substituting
f = exp(r*x)
into the homogeneous equation
f'' = a2 *f + a3*f'
and you get
r^2 = a2 + a3*r
and solve for 'r'; if you get two distinct roots, say, r1, and r2
the solution is
f0 = c1 * exp(r1*x) + c2*exp(r2*x)
if you get repeated root, say, r0
then the solution is
f0 = c1*exp(r0*x) + c2*x*exp(r0*x)
all the roots can be complex-valued.
Then you guess a special solution to the original equation
f'' = a1 + a2*f + a3*f'
say：
f1 = -a1/a2;
then the final solution is
f = f0 － a1/a2;
const |
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c**********e
发帖数: 2007 | 6 In word (or powerpoint), we can use "MicroSoft Equation 3.0" to add
equations.
In my home computer, I am using Vista. How to get the package installed? Do
I need to buy it? |
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c*****t
发帖数: 520 | 7 考虑reaction diffusion equation ：u_t=u_xx+f(u) ，x 定义域为实数集R ，t>0 。
假设f 是C^1 函数，以及在任意正时间T ，方程的解u(x,T)都属于H^1 空间。
若0 和1 为f 的零点（不排除f 还有其他零点），且令初值u(x,0)在0 和1 之间，则对
于任意x in R，t>0 ，解u(x,t)总在0 和1 之间。
我想知道解u(x,t)是否有如下性质：
若初值u(x,0)不是某个steady state（即u_xx+f(u)=0 的解），则对于任意0=
以及任意T>0 ，满足u(x,T)=A的x 值只有至多有限个。换言之，在任何正时间T ，方程
的解作为x-u 平面上的曲线，和直线u=A 只有至多有限个交点。
我的问题的动机，是我猜测reaction diffusion equation 如果不是初始即为steady
state ，那么在演化过程中，解不可能在某处严格“平坦”。即对于所有T>0 ，解在某
个区间(a,b) 上满足u(x,T)=A，或者对于某个收敛列{x_n} 满足u(x_n,T)=A，都是不可
... 阅读全帖 |
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n***p
发帖数: 7668 | 8 Is that a differential equation? Why does it have dx in both the numerator
and the denominator? Can they be cancelled? If yes, then there will not be
dx and how can it be a differential equation? |
|
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s*****e
发帖数: 20 | 10 pde 中的Wave equation，套公式就可以得解。小弟这有个damped wave equation，望
哪位大哥给个帮助啊
\partial_t^2 u(t,x) +\partial_t u = \Delta u +\sigma(u) \dot w
u (0,x) = f(x)
\partial u(0,x) = g(x)
where \dot w is white noise. |
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p*******5
发帖数: 6446 | 11 【 以下文字转载自 Physics 讨论区 】
发信人: pooh91125 (从肥膘中出窈窕，于肚腩处显细腰), 信区: Physics
标 题: 包子求教：collisionless Boltzmann equation
发信站: BBS 未名空间站 (Wed Jan 23 03:36:39 2013, 美东)
有个问题想请教一下：请问有什么好的教材或文献讲collisionless Boltzmann
equation? Specifically I'm interested in its steady-state solutions. |
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S*****n
发帖数: 6055 | 12 【 以下文字转载自 Chemistry 讨论区 】
发信人: Synthon (合成子·生命中的一点缠结), 信区: Chemistry
标 题: Question on Scherrer Equation (with baozi)
发信站: BBS 未名空间站 (Tue Apr 10 12:22:09 2012, 美东)
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! |
|
j******i
发帖数: 6 | 13 To anybody who knows black-scholes model and stochastic differential
equation or anybody who knows control theory.
dS=αSdt+βSdB, S denote the price of a stock depends on t,S(t), α is the
drift or rate of return, β is the volatility, B is brownian motion.
How do I incorporate the control parameter γ , and a number “ L “defined
as dN/dS, where N denotes the amount of asset traded and S denote the asset
price so that dS=(αS+γ/L)dt+βSdB
defines a differential equation.
Thank you in advance |
|
d********t
发帖数: 9628 | 14
一个theorem也有equation啊，至少Xinfeng Zhou里提到了FK equation了。 |
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B****n
发帖数: 11290 | 15 causal model裡面的箭頭只能是單向的 因為causality是有先後的關係
structural equation model則無此限制 所以應該不能說structural equation model
一定是causal model
VAR |
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D*********Y
发帖数: 3382 | 16 In my equation system, I also have endogenous variables on the right hand
side of the equation. I wonder whether I set up the systems too complicated.
I want to try linear specification now. What is the probelm is I go with
linear specification but not non-linear regressions which is supposed to be
the correct setup. |
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a******n
发帖数: 11246 | 17 我在build一个model的时候，用proc MI来impute missing values，然后得到一个
model equation。
现在我需要用这个equation来predict，那么input里的missing value怎么处理呢？用
同一个变量在build sample里的mean/median？还是有更好的办法？
Thanks! |
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l******9
发帖数: 579 | 18 I need to solve system equations of integrals in python 3.2.
from sympy import S, Eq, solve, integrals
import sympy as sym
import scipy.integrate as integ
x, b, c, m, v, L, u = S('x, b, c, m, v, L, u'.split())
equations = [Eq(m, integ.quad(xf(x, b, c), L, u))]
def xf(x, b,c):
return x*f(x,b,c)
def f(x, b, c):
return g(x, b,c) * (x/b)**(c-1) * sym.exp(-x/b)
def g(x, b, c):
c = 1+c // TypeError: unsupported operand type(s) for +: 'int' and '
tuple'
L = 1
u = 10
... 阅读全帖 |
|
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T*********r
发帖数: 11175 | 20 很多符号最后被直接转成了equation editor的格式
个别不识别，不过看你的latex2rtf的版本
我还不知道怎么加package
有latex能通过的文件，这个latex2rtf不认 |
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t**********r
发帖数: 182 | 21 I am running simultaneous equation. SAS code is like this:
proc tcalis data=reg6 pshort nostand;
lineqs
depvar1 = xxx + E1,
depvar2 = xxx + E2;
std
E1-E2 = eps1-eps2;
cov
E1-E2 = eps3; |
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j******u
发帖数: 1968 | 22 我刚刚搞清楚了，
你首先要现在ooolatex的extension，这个文件google就能找到，后缀是oxt的
现在到本地以后打开writer/impress，找到里面的一些extension的选项，安装新的
extension
系统会提示你找文件，就是刚才下的那个oxt文件
成功安装以后，你会发现在你的toolbar上出现equation expand config这三小键
第一次使用要config一下，主要是找到gs 和latex的安装目录，我用linux/debian，所
以应当是
/usr/bin
windows没用过，所以不知道，呵呵
用了用，效果还可以 |
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k*****r
发帖数: 21039 | 23 okay, the whole thing works beautifully now.
after installing this ooolatex oxt, it renders latex equation beautifully.
the only problem is that after installing emf package, it did not work due
to missing libstdc file in 9.10. have to fix that. |
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a*********n
发帖数: 1331 | 24 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2SLS 或Simultaneous equations model怎么做？
或者其他方法？ |
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a*********n
发帖数: 1331 | 25 谢谢。改了标题。
用simultaneous equations model怎么做？ |
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m*****k
发帖数: 731 | 26 Crystal Equation 要ssn,
说是客户要求的,不然没法递简历。
有人遇到类似情况么？还说他们管办H1B, 不知是否ICC. |
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h**********n
发帖数: 104 | 27 沃尔玛的Equate的复合维生素和其他牌子的功效一样吗 价钱差很多哦
Evening Primrose Oil 有用吗 好像说法分歧挺大的 |
|
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e*****r
发帖数: 3967 | 29 equator现在也不很娱乐了，还是两块肌同学最富余娱乐精神。 |
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i**i
发帖数: 27 | 30 hi, GG and MM, please help me on the equation: greatfully appreciated! |
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s*****n
发帖数: 536 | 31 The equation is
d( d(Fy)/d(lamda) )/d(lamda) + (2/x) * ( d(Fy)/d(lamda) )
=3.91*(Fy*Fy)
d(Fy)/d(Lamda)=0 when lamda=0
Fy(lamda=1)=1
ask for d(Fy)/d(Lamda)=? when lamda=1
My question: what is x? Is it lamda in your gif file? |
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m******g
发帖数: 2 | 32 THE EQUATION IS
A*\EXP(B*T)+C*\EXP(D*T)=E
WHERE A, B, C, D AND E ARE CONST. T IS A VARIABLE. |
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f*******h
发帖数: 1269 | 33 Let x = exp(BT).
Then you will get an equation:
x = C1 - C2*X**(d/b)
(constant omitted)
Then just select an intial value and iterate until it converges. |
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g********g
发帖数: 11 | 34 In general, no.
It is known that there's no closed form solution for equations with order
greater or equal than 5 (or 6?), so when d/b >5, no closed form. |
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k*****r
发帖数: 21039 | 35 can someone recommend a workable one ?
i am using OpenOffice + Latex equations on XP, want to keep it that way. |
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k*****r
发帖数: 21039 | 36 no, my students can't deal with latex. they use word.
to compromise, i ask them to switch to OpenOffice, but use LaTex equation
editor, as we are using it in the Google doc already.
so, just something like MathType, but free, for Ubuntu. |
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o**n
发帖数: 1249 | 37 non-math/physics students would seldom like to learn latex, so lz wants a
WYSIWYG equation editor for these students. |
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r****t
发帖数: 10904 | 38 check some online equation editor... |
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p*****s
发帖数: 7 | 39 然后word 里显示的是‘embed equation. 3', 不能直接看到公式，怎么样才能显示公
式呢？
还有我在word里加网址，也是类似的hyperlink, 我以前的word不这样啊，不知道怎么
改变这个功能。 |
|
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b*****o
发帖数: 284 | 41 你可以转换MathType到Equation, Object没有办法。自己搜个转换器吧，我以前做
dissertation的时候用过，具体叫什么不记得了。 |
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T*******n
发帖数: 493 | 42 Here is another hack, probably more useful to those who are
familiar with the American Physical Society Physical Reviews
revtex4.cls template.
Save the following as rvtxwdeq.sty (RevTeX4 wide equation):
\let\wideeqn@outdent\@empty
\newenvironment{wideeqn@galley}{%
\list{}{%
\topsep \z@skip
\listparindent \parindent
\itemindent \parindent
\leftmargin \z@
\parsep \z@\@plus\p@
\wideeqn@outdent
\relax
}%
\item\relax
}{
\endlist
}%
\def\title@co |
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T*******n
发帖数: 493 | 43 \displaystyle is not meant to be used this way, and neither is \large and
similar text font size commands though as a hack they will work.
I think if you arbitrarily increase the size of "e" then you will need to
increase the size of the "p(t)", but these would then look strangely large
compared with the text font size. To me without the \displaystyle things
look correct, but ultimately \exp is the better way to set the equation.
_0 |
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g********d
发帖数: 4174 | 44 Sorry for the entry-level question. I need equation numbers such as 2.1, 2.2
... not (1), (2). Thanks. |
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S**I
发帖数: 15689 | 45 \usepackage{amsmath}
\numberwithin{equation}{section}
.2 |
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S**I
发帖数: 15689 | 46 这个实现有两个问题：第一，公式是以inline mode，而不是display mode显示；
第二，inline mode的公式没有编号。得做些修改才能实现跟flalign环境类似的效
果：
\stepcounter{equation}
\begin{flushleft}
$\displaystyle ... $ \hfill $(\theequation)$
\end{flushleft} |
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z***i
发帖数: 8285 | 47 俺自己还真没试过，flushleft都是用在图片位置上和url什么的。。
这个实现有两个问题：第一，公式是以inline mode，而不是display mode显示；
第二，inline mode的公式没有编号。得做些修改才能实现跟flalign环境类似的效
果：
\stepcounter{equation}
\begin{flushleft}
$\displaystyle ... $ \hfill $(\theequation)$
\end{flushleft} |
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n***l
发帖数: 1468 | 48 latex写文章,
可否把equation, algorithm, table这3个environment里面的东西, 统统缩小一点? 要
不然太占地方了.
就像\includegraphics[scale=0.3]{aaa.eps}一样, |
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a****9
发帖数: 418 | 49 可以用\small试试 往下面还有\tiny \footnotesize
{\small
\begin{eqnarray*}
Your equation
\end{eqnarray*}
} |
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T*********r
发帖数: 11175 | 50 【 以下文字转载自 Faculty 讨论区 】
发信人: TechniColor (坚决服从rourou的领导), 信区: Faculty
标 题: Re: latex equation editor
发信站: BBS 未名空间站 (Wed Oct 21 03:29:21 2009, 美东)
linux下latex2html阿
或者是mac下的simpletex2ht
\documentclass[12pt]{article}
\usepackage{graphicx}
\usepackage{amssymb}
\usepackage{color}
\definecolor{darkblue}{rgb}{0.3,0.3,0.6}
\usepackage[
colorlinks=true,
linkcolor=darkblue, urlcolor=darkblue,
anchorcolor=darkblue, filecolor=darkblue,
linkcolor=darkblue, menucolor=darkblue |
|
