Okay, thank you.

So everybody can hear me.

This is my first time being to AUC conference, so I will give a short introduction of myself.

I studied in China and then I went to Helmuth Group as an exchange student to do my master's

thesis and afterwards I found it's really interesting to work with AUC.

Then I continued my PhD in Helmuth Working Group and after that I went back to China

and started my work as assistant professor and now I'm an associate professor in Shanghai,

East China Normal University.

So it's like I have been working with AUC for several years, but this is my first time.

I'm so happy to see all of you here because previous time I only, I know all your name

on the paper, on the publication, but now I meet you in person.

So this is my AUC equipment in my lab.

I got it as a present on the last day of 2017, so an XP-N80 machine.

It's a normal ultracentrifuge.

And then the next year, I think it was in May, Helmuth visited my lab and in that picture

he was just showing how to get the rotor away from the vacuum chamber.

And afterwards I sent the wire cane from the vacuum chamber and also the heat sink beneath

the stuff to Nanolytics, to Christian, and he helped me to drill the holes and he sent

it back to me.

But in the end I still need to cut the electronic board to get some space here to put my optical

arm to build in the optical arm.

So you can see here I have two wire canes here.

It's because I've broken a lot of parts in my UC, but finally I made it.

So you can see there's always a mess in my lab for three and four years and finally now

it's looking like this.

It's working now.

And I thank you so much for the engineering.

And this is the topic of my talk today.

So it's a question, can we make use of AUC characterizations to better control the fractionation

in preparative ultracentrifuge?

So I call it PUC.

You see actually there's some difference in the cell of AUC and what we use here, a swing

out rotor in the preparative machine.

And I can show you some possibilities and also I study a little bit of limitation of

this combination.

Our first example is about a binary colloidal particle system.

What we have done is we synthesized the polystyrene particles with two different sizes and put

them together and make a binary mixture and measure them with AUC and we can see clearly

here with a mixture you have two different groups.

And afterwards we also study the concentration dependence.

It's not linear because we went to very high concentration of the particles.

But anyway we can have a difference between the two groups of the particles and combine

it with some like particle concentration and also the column lengths in the preparative

centrifuge.

In the end we can obtain different packing or different fractionations in the preparative

centrifuge tube.

And here you can see we can achieve a very sharp separation of the smaller particle and

also between the smaller particle and the larger particle.

And we can also obtain a gradient in between and some random gradient and in the end we

can just have some structures in the centrifuge tube.