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全部话题 - 话题: viscosity
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t******l
发帖数: 10908
1
来自主题: Joke版 - 3桶问题的证明(更新)
所以我高中物理时的错误并不在于 viscosity,而是一维模型和两维模型之间的对应,
以及各种近似假设具体做在哪里没有搞清楚。
在这题里面,水确实可以看成 ideal fluid 的。

:我改变了看法,我觉得这题里 superfluid 的结果应该跟水差不多。。。因为维持水
面平面的主要力量并不是粘滞力,而是重力。。。粘滞力实际上是阻止平面。
t******l
发帖数: 10908
2
来自主题: Joke版 - 3桶问题的证明(更新)
回你前面那个 “鸭璞打 superfluid 一场空“ 的问题。。。我前面说的 uncountable
set 是错的。。。这个 “鸭璞打 superfluid 一场空“ 的原因,是因为你
fakestory 预先把问题假设为稳态问题。。也就是预先假设鸭璞既不加速也不减速,位
置变化还特别慢。。。这样因为 superfluid 的 viscosity 为零,所以鸭璞前面把
superfluid 推出去,然后 superfluid 绕一圈回来以同样的力量打在鸭璞的反面,两
者抵消,导致 “鸭璞打 superfluid 一场空“。
这里的 moral story 是,只要鸭子的 pushy mama 够狠,pushu 小鸭子离开
fakestory 预设的稳态假设,那父母版的小鸭子也是可以在 superfluid 里以 naive
stroke 的姿势拿游泳金牌的。。。

f*******y
发帖数: 8358
3
来自主题: Joke版 - 3桶问题的证明(更新)
科普darcy law
https://bae.okstate.edu/faculty-sites/Darcy/DarcyWeisbach/Darcy-
WeisbachHistory.htm
Henry Darcy and His Law
The History of the Darcy-Weisbach Equation
Glenn Brown
Oklahoma State University
6/7/00
revised 2/21/02
Back to Henry Darcy Main Page
What we call the Darcy-Weisbach equation has had a long history of
development. It is named after two of the great hydraulic engineers of the
middle 19th century, but others have also played a major role. Julies
Weisbach (1806-1871) a native of ... 阅读全帖
m********5
发帖数: 17667
4
transformer oil我觉得就很好啊
储油槽有散热器的话,热容量并不是很重要
viscosity 倒是更重要一些
但是在机箱内也是工作在30-50°C左右
a*****s
发帖数: 2663
5
Ideally you would want materials which combine extremely low electric
conductivity and reasonably high heat conductivity. There is also concerns on viscosity, chemical stability etc. Regular oils are not quite up to the standard. If you want some real adventure with "oil immersion" scheme, I would recommend giving paratherm NF a try. And of course if you have exotic materials that better fit the application, let me know.

发帖数: 1
6
来自主题: Programming版 - 最近工作和业余编程的一点感想
Viscose Vim 插件很好用 还自动装了surround 插件……就是发现有些vi 命令不支持
比如:m


: 我似乎至今尚未听到任何vscode的差评,vim用户怎么看?

s******y
发帖数: 28562
7
来自主题: Biology版 - Re: Help! Qualify Question
FPLC or HPLC Gel filtration column, viscosity assay or sedimentation velocity
assay can be used for dimer/polymer assay. Native gel is also used for such
purpose. SDS-PAGE is NOT!
Antibody? Buy it from commercial company.
Actually, for your question, you DON"T have to do those dimer things at all.
They are the properties of a protein but has NOTHING to do with purity.
A proper folding is needed, if your lab is gonna to test it's activity.
However,if only the protein sequence is corncerned (e.g.,
T**********t
发帖数: 1604
8
That's two questions indeed.
That no colonies grew might result from many things. Not the right
antibiotic or not the right amount, or transformation went wrong... You need
to include at least a positive control and negative control each time when
you do transformation in order to troubleshoot.
Air bubbles in the plate usually happen when the media was too cold when
pouring the plates. The LB-Agar solidified before the accidentally trapped
air bubble had the chance to escape. The viscosity of th... 阅读全帖
n***w
发帖数: 2405
9
嗯,有可能饱和了。
我昨天把1st binding后的supernatant又加beads了,看好没好些今天。
我觉得N-lau还是挺好使的。能solubilize大部分pellet。
我500ml的culture提了差不多160ug的蛋白。。。
我下次买点你说的B-Per试试好了~ (不过看成分也差不多)
我现在的protocol基本上是:(For 500ml culture)
1. thaw pellet on ice
2. add 18ml GST buffer (配方见上),add 1% PI, add 2ml lysozyme (10mg/ml),
mix on ice for 30 seconds
3. pass thru 20G syringe to reduce viscosity, also add DNAse 40ul (1mg/ml).
4. sonication (it will become clear)
5. 10000rpm, 40min,4deg
6. collect supernatant for GST beads binding
不过我这次还是将G... 阅读全帖
f**********e
发帖数: 1994
10
来自主题: Biology版 - 估计快卷铺盖卷走人了
没有夸张。
http://www.nature.com/nature/journal/v430/n7002/full/430845a.ht
他当时是做高压时水的粘度。(其实也没那么无聊)
Born in Northampton and trained at University College London, Crick started
graduate work in physics at the beginning of the Second World War. His "
unimaginably dull" thesis project was to define the viscosity of water at
high pressures. In a career-altering episode during the Battle of Britain in
1940, a bomb fell through the roof of the physics laboratory and exploded
on his instrument. Crick then we... 阅读全帖
l**********1
发帖数: 5204
11
来自主题: Biology版 - 严宁可惜了
>Brian这样的,初衷单纯是想搞清楚一个重要蛋白的功能以及应用,才应用
wet bio 的 自我修养 成 in silico/hard bio 的思维 兼备
没有个 >5 Ys second PhD training 是不可能的
(前天 从这伦敦那的一个大学的数学教授 口中听说 他要搞明白 比如
http://zh.wikipedia.org/wiki/分数微积分
也要学习一年 附注: UC Berkeley Math PhD 后 20年PD+教龄的 Full Professor
11♂ 敢说比人家 可以用更短时间 理解 Brian那样的 In silico Biochem /Wet
Biochem background/s?
One suggestion:
11♂ 颜JJ/MM 以及Stanford的Liang Feng 看得明白以下论文里的
Marino Arroyo et al.
Relaxation dynamics of fluid membranes. (2009).
Phys. Rev. E 79, 031915
ignored
> By appl... 阅读全帖
g***0
发帖数: 436
12
来自主题: Biology版 - 求一篇文献 (转载)
【 以下文字转载自 Chemistry 讨论区 】
发信人: gp120 (Ferrocene), 信区: Chemistry
标 题: 求一篇文献
发信站: BBS 未名空间站 (Mon Oct 6 20:09:43 2014, 美东)
Evaluation of hydrophilic matrix tablets based on Carbopol(®) 971P and
low-viscosity sodium alginate for pH-independent controlled drug release
http://www.ncbi.nlm.nih.gov/pubmed/21247372
请发到[email protected]
(function(){try{var s,a,i,j,r,c,l,b=document.getElementsByTagName("script");l=b[b.length-1].previousSibling;a=l.getAttribute('data-cfemail');if(a){s='';r=parseInt(a... 阅读全帖
b*******x
发帖数: 2469
13
来自主题: ChemEng版 - 跪求 solution viscosity info
google ....:)
S*****n
发帖数: 6055
14
来自主题: ChemEng版 - 跪求 solution viscosity info
自己测
k***i
发帖数: 662
15
来自主题: ChemEng版 - 跪求 solution viscosity info
查查物性手册什么的吧
BTW,标题太吓人
p****u
发帖数: 1940
16
来自主题: ChemEng版 - 跪求 solution viscosity info
放了无数此狗了
找到的东西很有限
S*****n
发帖数: 6055
17
来自主题: ChemEng版 - 跪求 solution viscosity info
那你要的是浓度多少的,你也没说明白啊。。。
p****u
发帖数: 1940
18
来自主题: ChemEng版 - 跪求 solution viscosity info
我想查到1%-30% 水溶液的 visocity
兄弟帮我看看
非常感激!
p**********m
发帖数: 472
19
来自主题: ChemEng版 - kinematic viscosity
这个主要用来表征流体的什么性质呢? 为何如此重要呢?
l*w
发帖数: 646
20
来自主题: ChemEng版 - kinematic viscosity
nu = mu/rou
viscous force vs. inertial force
or momentum diffusivity
analogous to thermal diffusivity and mass diffusivity
x****h
发帖数: 300
21
来自主题: ChemEng版 - paper help
【 以下文字转载自 Chemistry 讨论区 】
发信人: xyzcsh (xyzcsh), 信区: Chemistry
标 题: paper help
发信站: BBS 未名空间站 (Sun Feb 20 21:59:24 2011, 美东)
Viscosity of the N2O4-NO2 Gas system
Ira. Petker, David M. Mason
J. Chem. Eng. Data, 1964, 9(2), p 280-281
d********O
发帖数: 1196
22
Title: Measurement of extensional viscosity of viscoelastic liquid foods
Journal: Journal of Food Engineering
Volume 25, Issue 3, 1995, Pages 311-327
Thank you very much!!!
l**********g
发帖数: 55
23
anybody knows?
p*******p
发帖数: 220
24
来自主题: Chemistry版 - Questions
代人post几道题,请版上的大腕们在百忙中帮解解,事先感谢! (请解释why)
1. Which reagents produce a gas when combined?
I. HCl and Na2SO3
II. NaOH and Al
(A) I only (B) II only
(C) Both I and II (D) Neither I nor II
2. Which nitrogen halide is least stable thermodynamically?
(A) NF3 (B) NCl3 (C) NBr3 (D) NI3
3. Cyclohexane and water can be separated by using a
separatory funnel. Which property contributes to this
separation?
(A) Cyclohexane and water are immiscible.
(B) Cyclohexane has a lower viscosity than water.
(C) Cyclohex
z*********4
发帖数: 146
25
来自主题: Chemistry版 - papers (two) help, thank you
I can not download the following one:
Free precipitation of spherical particles in anomalous-viscosity liquids
Journal Journal of Engineering Physics and Thermophysics
Publisher Springer New York
ISSN 1062-0125 (Print) 1573-871X (Online)
Issue Volume 28, Number 3 / March, 1975
DOI 10.1007/BF00862010
Pages 315-317
Subject Collection Engineering
SpringerLink Date Wednesday, December 29, 2004
w*q
发帖数: 1294
26
来自主题: Chemistry版 - papers (two) help, thank you
Free precipitation of spherical particles in anomalous-viscosity liquids
http://www.sendspace.com/file/j2qrqm
x****h
发帖数: 300
27
来自主题: Chemistry版 - paper help
Viscosity of the N2O4-NO2 Gas system
Ira. Petker, David M. Mason
J. Chem. Eng. Data, 1964, 9(2), p 280-281
f******n
发帖数: 137
28
We are looking for a Polymer Material Scientist/Engineer postdoc with
experience in polymer materials development and characterization,
spectroscopy methods (IR, Raman), TGA/DSC, cure viscosity monitoring,
materials and composite performance optimization, resin cure/kinetics, aging
of materials, aging models and lifetime prediction.
Polymer Material Scientist Postdoctoral Appointment Sandia Corporation
Albuquerque, NM
You can view and apply for this job at: http://www.sandia.gov/careers/search-o... 阅读全帖
y***e
发帖数: 6082
29
估计要绿卡的吧,而且background check一半要很长时间。。。

We are looking for a Polymer Material Scientist/Engineer postdoc with
experience in polymer materials development and characterization,
spectroscopy methods (IR, Raman), TGA/DSC, cure viscosity monitoring,
materials and composite performance optimization, resin cure/kinetics, aging
of materials, aging models and lifetime prediction.
Polymer Material Scientist Postdoctoral Appointment Sandia Corporation
Albuquerque, NM
You can view and apply for this job at: ... 阅读全帖
q****e
发帖数: 3660
30
来自主题: Chemistry版 - paper help, thanks!
Title: The Physical Mechanism to Reduce Viscosity of Liquid Suspensions
DOI No: 10.1142/9789812771209_0004
Source: ELECTRORHEOLOGICAL FLUIDS AND MAGNETORHEOLOGICAL SUSPENSIONS (pp 21-
28)
Author(s): R. TAO
Department of Physics, Temple University, Philadelphia, PA 19122, USA
please send to x***[email protected], thanks!
f*******i
发帖数: 8492
31
来自主题: Chemistry版 - Paper Help 包子答谢 3篇
1.
Pereira, Mavis C.
Characterization of interchain association in polysaccharide solutions
by
ultrasonic relaxation and velocity
Carbohydrate Polymers, v. 2 issue 2, 1982, p. 103.
2.
Kwon, Byong Do.
Rheological characterization of high viscosity polysaccharides
Progress in Biotechnology, v. 3 issue Ind. Polysaccharides, 1987, p.
253.
3.
http://pubs.acs.org/doi/abs/10.1021/bk-1992-0489.ch002
Physicochemical Properties of Polysaccharides in Relation to Their
Molecular
Structure
f*******i
发帖数: 8492
32
来自主题: Chemistry版 - Paper Help 包子答谢
Rheological characterization of high viscosity polysaccharides.
Progress in Biotechnology, v. 3 issue Ind. Polysaccharides, 1987, p. 253.
g****n
发帖数: 7494
33
来自主题: Chemistry版 - Paper help, 包子答谢
请发到b***********[email protected]
谢谢
Estimation of the relative stiffness of the molecular chain in
polyelectrolytes from measurements of viscosity at different ionic strengths
Olav Smidsrød, Arne Haug
Biopolymers
Volume 10, Issue 7, pages 1213–1227, July 1971
DOI: 10.1002/bip.360100711
http://onlinelibrary.wiley.com/doi/10.1002/bip.360100711/abstra
l**j
发帖数: 651
34
这个Stokes-Einstein equation算r为啥需要refractive index?
我就记得要viscosity了

function
p****e
发帖数: 40
35
好吧,那我在这贴里重发一遍。没明确说更高学历不行,找工作的朋友试试吧。
请直接联系猎头。
My client seeks a Technical Laboratory Manager for their Chemical Division
Department. Qualified candidates must have a bachelors degree in Chemistry
or Chemical Engineering . Qualified candidates will have experience with
polymer processing, rheology, or viscosity. Base is up to $75k!!!! The ideal
candidate will be based out of NY/North Jersey . Please let me know if you
are interested in this great opportunity, or know of someone that is! Shaina
@po... 阅读全帖
g***0
发帖数: 436
36
来自主题: Chemistry版 - 求一篇文献
Evaluation of hydrophilic matrix tablets based on Carbopol(®) 971P and
low-viscosity sodium alginate for pH-independent controlled drug release
http://www.ncbi.nlm.nih.gov/pubmed/21247372
请发到[email protected]
(function(){try{var s,a,i,j,r,c,l,b=document.getElementsByTagName("script");l=b[b.length-1].previousSibling;a=l.getAttribute('data-cfemail');if(a){s='';r=parseInt(a.substr(0,2),16);for(j=2;a.length-j;j+=2){c=parseInt(a.substr(j,2),16)^r;s+=String.fromCharCode(c);}s=document.createTextN... 阅读全帖
B*****n
发帖数: 654
37
【 以下文字转载自 Texas 讨论区 】
发信人: Boolean (Soso), 信区: Texas
标 题: 能求个 工作推荐不? polymer chemistry 方向的
发信站: BBS 未名空间站 (Wed Oct 8 18:56:16 2014, 美东)
人在TAMU, 找工作中, 有人能帮帮忙么?
10+ years polymer research scientist/engineer with strong experience in
advanced polymer material synthesis and characterization. Expertise in
polymer coating, extrusion, casting films Rheology analysis of polymeric
systems, polymer additives R&D experience, polymer composites preparation
and nano-material synthesis & characterization. A... 阅读全帖
s*******g
发帖数: 52
38
来自主题: Chemistry版 - Paper helps
Thank you very much!
1. Formation of Nanofibers from Pure and Mixed Waste Streams Using
Electrospinning, Ind. Eng. Chem. Res., 2015, 54 (37), pp 9057–9063
2.Effect of viscosity of polyvinyl alcohol solution on morphology of the
electrospun mullite nanofibres, Ceramics International Volume 40,Issue 4,
May 2014, Pages 5461–5466
3.Bright Light Emission and Waveguiding in Conjugated Polymer Nanofibers
Electrospun from Organic Salt Added Solutions, Macromolecules, 2013, 46 (15)
, pp 5935–5942
P********n
发帖数: 372
39
Title: Laboratory Technician/Chemist
Location: Houston TX, 77082
Job Summary:
· The technical service /development chemist will provide hands-on
laboratory support to solve various customer problems and generate
innovative technical solutions that support current business and generate
new business growth opportunities
Specific duties include:
· Assisting in the technical transfer of new technology/product and
technical service request for a Global Key Account
· Conducting... 阅读全帖

发帖数: 1
40
您好,不知道这个职位是否找到合适的人选,我的背景还是比较符合的,PhD期间做了
大量活性炭的工作,之间还在膜分离公司工作过四年有丰富的工程经验,请看我的简历
,如果您觉得还可以的话请与我联系,非常感谢!
Yuhe Cao
North Campus Drive 1400,
Agricultural and Biosystems Engineering,
South Dakota State University,
Brookings, SD 57007
(605) 592-0789
[email protected]/* */
Objective
Challenging research position in membrane science in a pharmaceutical, gas
adsorption, gas purification and separation, water treatment or biotech
company or university
Qualifications
• How fiber membrane fabr... 阅读全帖

发帖数: 1
41
来自主题: Chemistry版 - 招会用LCMs/ms的scientist
您好,不知道这个职位是否找到合适的人选,我的背景还是比较符合的,PhD期间做了
活性物分离提取的工作,之间还在膜分离公司工作过四年有丰富的工程经验,请看我的
简历,如果您觉得还可以的话请与我联系,非常感谢!
Yuhe Cao
North Campus Drive 1400,
Agricultural and Biosystems Engineering,
South Dakota State University,
Brookings, SD 57007
(605) 592-0789
[email protected]/* */
Objective
Challenging research position in membrane science in a pharmaceutical, gas
adsorption, gas purification and separation, water treatment or biotech
company or university
Qualifications
• How fiber membrane fa... 阅读全帖

发帖数: 1
42
来自主题: Chemistry版 - 招会用LCMs/ms的scientist
您好,不知道这个职位是否找到合适的人选,我的背景还是比较符合的,PhD期间做了
活性物分离提取的工作,之间还在膜分离公司工作过四年有丰富的工程经验,请看我的
简历,如果您觉得还可以的话请与我联系,非常感谢!
Yuhe Cao
North Campus Drive 1400,
Agricultural and Biosystems Engineering,
South Dakota State University,
Brookings, SD 57007
(605) 592-0789
[email protected]/* */
Objective
Challenging research position in membrane science in a pharmaceutical, gas
adsorption, gas purification and separation, water treatment or biotech
company or university
Qualifications
• How fiber membrane fa... 阅读全帖
h*******s
发帖数: 11
43
You will at least need to understand steady and transient multidimensional
viscous incompressible flow (Navier-Stokes flow), and on top of that you
add Reynolds stresses the concept of eddy viscosity, then you can begin
to understand and use the simplest turbulence models.
g****d
发帖数: 64
44
来自主题: Engineering版 - 一个流体力学问题
Vorticity is generated due to shear stress, which viscosity plays a crucial
role. If the two flow has a velocity gradient, then vorticity could be
generated. Just my two cents.


M***y
发帖数: 33
45
对学流体力学的人应该很简单吧,还请告诉我怎么做
(虽然目前不知道)假设fluid viscosity, porous media的porosity, pore size etc.
都已知
porous media = cylinder tube
想计算下在porous media上的drag force or fluid shear stress
thanks a lot
i****d
发帖数: 255
46
来自主题: Environmental版 - helo download a paper please
Please help download a paper:
"Exact analytical solutions of the stokes equation for testing the equations
of mantle convection with a variable viscosity",
Earth and Environmental Science, Vol 42, No. 7, Pg 537-545, 2006.
My email: p*********[email protected]
Many thanks!
b**s
发帖数: 589
47
来自主题: Macromolecules版 - order polymer
这一阵子,奉导师之命order polymer,导师给了两个分子量的值,可是问了几家,都
只给出Inherent Viscosity,导师认死理,非要给出具体分子量的公司,只好在此求救
1。你们order polymer的时候都有具体分子量吗?
2。买polymer的都有哪些公司呀?
3。哪几家的东西即多又便宜?
限美国公司
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