z**h
发帖数: 224 | 1 Flory-Huggins interaction parameter 的演变 和de Genns 的screening length
or correlation length 的衍生。
不知大家以为如何？ | c*****e
发帖数: 238 | 2 至少不应该不提path integral.
de Gennes的screening length是field theory和scaling的结果.
那个的根本来源是renormalization,自然少不了path integral.
Flory Huggins作为非常coarse的mean field limit
借助field theory, de Gennes才能计算出\nu, 虽然结果与flory的结果相近,
但内涵差的多.
【在 z**h 的大作中提到】
: Flory-Huggins interaction parameter 的演变 和de Genns 的screening length
: or correlation length 的衍生。
: 不知大家以为如何？
| z**h
发帖数: 224 | 3 The correlation length was obtained without the mean field approximation(?).
I need to check the book.
【在 c*****e 的大作中提到】
: 至少不应该不提path integral.
: de Gennes的screening length是field theory和scaling的结果.
: 那个的根本来源是renormalization,自然少不了path integral.
: Flory Huggins作为非常coarse的mean field limit
: 借助field theory, de Gennes才能计算出\nu, 虽然结果与flory的结果相近,
: 但内涵差的多.
| w********h
发帖数: 12367 | 4 我的感觉是你把screening length的重要性摆得太高了。
基本赞同cashine提到的path integral的重要性。
approximation(?).
【在 z**h 的大作中提到】
: The correlation length was obtained without the mean field approximation(?).
: I need to check the book.
| b*o
发帖数: 47 | 5 Personally, I think the picture on flexible, long homopolymers is quite clear
now. The frontier of polymer physics might be heteropolymer physics, such as
protein folding.
length
【在 w********h 的大作中提到】
: 我的感觉是你把screening length的重要性摆得太高了。
: 基本赞同cashine提到的path integral的重要性。
:
: approximation(?).
| z**h
发帖数: 224 | 6 Is path integral a mathmatical procedure?
length
【在 w********h 的大作中提到】
: 我的感觉是你把screening length的重要性摆得太高了。
: 基本赞同cashine提到的path integral的重要性。
:
: approximation(?).
| c*****e
发帖数: 238 | 7 算是吧,但意义不同,至少现在可以很好地将polymer的问题融入更大的范畴,而且可以找出
共同点,使用解决其他体系的问题时采用的方法.
而且这个东西,实在挺漂亮.
【在 z**h 的大作中提到】
: Is path integral a mathmatical procedure?
:
: length
| c*****e
发帖数: 238 | 8 That's right. But I don't quite understand the most striking result obtained
by de Gennes, i.e. the connection between self avoiding walk and O(N) model.
The work done for flexible chains is quite a lot,
but I didn't learn the most beautiful parts yet and I still want to.
Nowadays most work on protein folding involves little physics, in my view.
Most work is based on old models and largely relies on computation.
A very excellent argument on the problem of conformations of protein is given
by de
【在 b*o 的大作中提到】
: Personally, I think the picture on flexible, long homopolymers is quite clear
: now. The frontier of polymer physics might be heteropolymer physics, such as
: protein folding.
:
: length
| w********h
发帖数: 12367 | 9 Even for flexible, long homo-polymers, the picture is not fully clear.
Reptation model still faces some challenging problems. For very long
chain, de Gennes predicted Stokes-Einstein behavior recovers but nobody
verified yet.
After all, Zimm, Rouse, Reptation and some boundry conditions are the
most successful approach to explain linear monodisperse polymers.
clear
【在 b*o 的大作中提到】
: Personally, I think the picture on flexible, long homopolymers is quite clear
: now. The frontier of polymer physics might be heteropolymer physics, such as
: protein folding.
:
: length
| w********h
发帖数: 12367 | 10
what's this? reference?
that's true.
I remember one classical book in this area was written long time ago.
given
other
clear
as
【在 c*****e 的大作中提到】
: That's right. But I don't quite understand the most striking result obtained
: by de Gennes, i.e. the connection between self avoiding walk and O(N) model.
: The work done for flexible chains is quite a lot,
: but I didn't learn the most beautiful parts yet and I still want to.
: Nowadays most work on protein folding involves little physics, in my view.
: Most work is based on old models and largely relies on computation.
: A very excellent argument on the problem of conformations of protein is given
: by de
| | | t***m
发帖数: 114 | 11
为什么极长链无法确定？是因为没有合适的模型高分子？
【在 w********h 的大作中提到】
: Even for flexible, long homo-polymers, the picture is not fully clear.
: Reptation model still faces some challenging problems. For very long
: chain, de Gennes predicted Stokes-Einstein behavior recovers but nobody
: verified yet.
: After all, Zimm, Rouse, Reptation and some boundry conditions are the
: most successful approach to explain linear monodisperse polymers.
:
: clear
| c*****e
发帖数: 238 | 12 The infinite self avoiding walk is equilivant to the (\phi^2)^2 model
at the limit N goes to 0, where N is the dimension of \phi, the order parameter
I still don't quite understand why this is the case...
The most cited paper is de Gennes, Phys. Lett. 1972...
I think this letter is cited almost everywhere when this topic is discussed
and it should not be too difficult to find it if you search it by google.
I will give the full reference if you still need this tomorrow(now I don't have
it at hand
【在 w********h 的大作中提到】
:
: what's this? reference?
: that's true.
: I remember one classical book in this area was written long time ago.
: given
: other
: clear
: as
| c*****e
发帖数: 238 | 13 A very interesting question proposed in de Gennes book, soft matter and hard
science(maybe not accurate as I read the chinese translation) is as follows:
The polymer solution is usually viscous and the dissipation is more pronounced
than the pure solvent, but this is verified only for laminar flow when the
Reynolds number is not too large. Experiments show that adding very few polymer
chains to the turbulent flow can effectively reduce the energy loss in the flow
he gave the example that adding
【在 t***m 的大作中提到】
:
: 为什么极长链无法确定？是因为没有合适的模型高分子？
| b*o
发帖数: 47 | 14 For complex systems such as polymers, I doubt that all details can be
clarified. However, I do think the big picture is there. For example,
Even for people like de Gennes, the importance of what he has been doing
recently,
such as polymers at interface, is not comparable with what he/his co-workers
did
in 1970/1980s. Most of the time, they just appllied the physics concepts into
more specific systems.
For heteropolymer physics, again, personally I think the late Tanaka had a
very
good begining,
【在 w********h 的大作中提到】
: Even for flexible, long homo-polymers, the picture is not fully clear.
: Reptation model still faces some challenging problems. For very long
: chain, de Gennes predicted Stokes-Einstein behavior recovers but nobody
: verified yet.
: After all, Zimm, Rouse, Reptation and some boundry conditions are the
: most successful approach to explain linear monodisperse polymers.
:
: clear
| z**h
发帖数: 224 | 15 when talking about the polymer physics, people seems to talk their
specific research filed. However, what is important is the foundation of
polymer physics. some concepts are widely used to derive new things, to
expand a new field. I think that is the reason that some people like de Genns
can win Noble prize.
into
of
such
【在 b*o 的大作中提到】
: For complex systems such as polymers, I doubt that all details can be
: clarified. However, I do think the big picture is there. For example,
: Even for people like de Gennes, the importance of what he has been doing
: recently,
: such as polymers at interface, is not comparable with what he/his co-workers
: did
: in 1970/1980s. Most of the time, they just appllied the physics concepts into
: more specific systems.
: For heteropolymer physics, again, personally I think the late Tanaka had a
: very
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