Tuesday, 10 April 2012

High-Resolution EM of Colloidal Nanocrystal Growth Using Graphene Liquid Cells Jong Min Yuk1,2,3,*, Jungwon Park2,4,*, Peter Ercius5, Kwanpyo Kim1,2,6, Daniel J. Hellebusch4,Michael F. Crommie1,2,6, Jeong Yong Lee3,†, A. Zettl1,2,6,†, A. Paul Alivisat

Science 6 April 2012: 
Vol. 336 no. 6077 pp. 61-64 
DOI: 10.1126/science.1217654
  • REPORT

High-Resolution EM of Colloidal Nanocrystal Growth Using Graphene Liquid Cells

  1. Jong Min Yuk1,2,3,*
  2. Jungwon Park2,4,*
  3. Peter Ercius5
  4. Kwanpyo Kim1,2,6
  5. Daniel J. Hellebusch4,
  6. Michael F. Crommie1,2,6
  7. Jeong Yong Lee3,
  8. A. Zettl1,2,6,
  9. A. Paul Alivisatos2,4,

+Author Affiliations

  1. 1Department of Physics, University of California at Berkeley, Berkeley, CA 94720, USA.
  2. 2Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
  3. 3Department of Materials Science and Engineering, KAIST, Daejeon, 305-701, South Korea.
  4. 4Department of Chemistry, University of California at Berkeley, Berkeley, CA 94720, USA.
  5. 5National Center for Electron Microscopy, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
  6. 6Center of Integrated Nanomechanical Systems, University of California at Berkeley, Berkeley, CA 94720, USA.
  1. To whom correspondence should be addressed. E-mail: j.y.lee@kaist.ac.kr (J.Y.L.); azettl@berkeley.edu (A.Z.);alivis@berkeley.edu (A.P.A.)
  1. * These authors contributed equally to this work.

ABSTRACT

We introduce a new type of liquid cell for in situ transmission electron microscopy (TEM) based on entrapment of a liquid film between layers of graphene. The graphene liquid cell facilitates atomic-level resolution imaging while sustaining the most realistic liquid conditions achievable under electron-beam radiation. We employ this cell to explore the mechanism of colloidal platinum nanocrystal growth. Direct atomic-resolution imaging allows us to visualize critical steps in the process, including site-selective coalescence, structural reshaping after coalescence, and surface faceting.

  • Received for publication 8 December 2011.
  • Accepted for publication 27 February 2012.

THIS ARTICLE HAS BEEN CITED BY OTHER ARTICLES:

BBC - Graphene windows' clearer focus Pockets formed in the graphene sheets allowed the team to study liquids at higher resolution Continue reading the main story Related Stories More uses for 'miracle material' Knighthoods for graphene pioneers Bendy ga

8 April 2012 Last updated at 08:44

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Graphene windows' clearer focus

The carbon-based material graphene can help scientists study liquids more clearly with high-power microscopes.

Details of the advance are reported in Science journal.

Graphene can form a clear "window" to see liquids at higher resolution than was previously possible using transmission electron microscopes.

Liquids had been difficult to view at the same resolution as solids because these microscopes require the liquids to be encapsulated by some material.

Traditionally, silicon nitride or silicon oxide capsules, or liquid cells, have been used. But these are generally too thick to see through clearly.

Now, Jong Min Yuk at the University of California, Berkeley, and colleagues have shown that pockets created by sheets of graphene can be used to study liquids at clear, atomic, resolution using transmission electron microscopes (TEMs).

The researchers used their new graphene-based liquid cell to study the formation of platinum nanocrystals in solution.

With this technique, the team of scientists was able to observe new and unexpected stages of nanocrystal growth as it happened.

They noted how the crystals selectively coalesced and modified their shape.

Graphene consists of a flat layer of carbon atoms tightly packed into a two-dimensional honeycomb arrangement.

Because it is so thin, it is also practically transparent. The unusual electronic, mechanical and chemical properties of graphene at the molecular scale promise numerous applications.

Its discoverers, Andre Geim and Konstantin Novoselov from Manchester University, were awarded the Nobel Prize for Physics in 2010.

Continue reading the main story

Graphene

  • Graphene is a form of carbon that exists as a sheet, one atom thick
  • Atoms are arranged into a two-dimensional honeycomb structure
  • Identification of graphene announced in October 2004
  • About 100 times stronger than steel and conducts electricity better than copper
  • About 1% of graphene mixed into plastics could turn them into electrical conductors
  • Analogous to millions of unrolled nanotubes stuck together

The technique described by Mr Yuk and colleagues might enable scientists to study other physical, chemical, and biological phenomena that take place in liquids on the nanometre scale.

"Their approach opens new domains of research in the physics and chemistry in the fluid phase in general," said Christian Colliex, from the Universite Paris Sud in France, who was not involved with the research.

In another paper published in this week's Science magazine, researchers from the US and Spain report that the stress of pressing the tip of an atomic force microscope into a thin film of material can switch the direction of the film's electric charge.

This phenomenon, called "flexoelectricity", could be harnessed to improve memory in electronic devices.

It could achieve this by allowing digital bits of information to be written mechanically but read electrically - which would use less power.

The process has been likened to a nanoscale typewriter - mechanically "writing" changes in the direction of electric charge.

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Monday, 9 April 2012

Bahrain unrest fuels calls for grand prix to be cancelled

Bahrain unrest fuels calls for grand prix to be cancelled

Grand prix should not go ahead amid violence on streets and a hunger strike by jailed activist, opponents say

Anti-grand-prix graffiti in Bahrain
A man walks past anti-Formula One graffiti in the village of Barbar, west of Manama. The words read: 'Boycott F1 in Bahrain, you will race on the blood of martyrs.' Photograph: Hamad Mohammed/Reuters

Pressure is growing for motorsport authorities to cancel this month'sFormula One race in Bahrain, amid continuing violence on the streets and a hunger strike by a jailed activist.

Protesters, human rights groups and MPs have called for the race, due on April 22, to be called off. They say it is unacceptable to go ahead with the grand prix while riot police are using teargas and live bullets against demonstrators, one of whom was shot dead last week.

The country's Sunni leadership is determined to hold the event. It argues that the revolt by the kingdom's Shia majority, – which began nearly 14 months ago and caused last year's grand prix to be abandoned, has mostly fizzled out.

In the run-up to the race, opposition supporters have plastered posters on walls and lambasted Formula One drivers via social media. "We don't want Formula One in our country," an activist, Ali Mohammed, told Associated Press during a recent rally in the capital, Manama. "They are killing us every day with teargas. They have no respect for human rights or democracy. Why would we keep silent? No one will enjoy the F1 in Bahrain with cries for freedom from the inside and outside of the race."

On Friday the British MP Richard Burden echoed a call by the former world champion Damon Hill for Formula One's governing body, the FIA, to think again. Burden acknowledged that some among the country's rulers were seeking genuine reform. "It is also true that not all the problems in Bahrain come from one side," he said.

But he pointed out that 45 people had been killed in Bahrain since February 2011, with police recently teargassing hundreds of protesters at a cemetery. "Bahrain is nothing like as bad as the terrible situation in Syria," he said. "And F1 teams do race in other countries with unenviable human rights records. But that does not mean it is right for F1 to collude in presenting to the outside world a cocooned picture of normality at the Bahrain international circuit, when what is likely to be going on just few miles outside the circuit could be very different indeed. "

Bahrain's Shia majority is demanding rights and opportunities equal to those of the Sunni minority that rules Bahrain. Crown Prince Salman bin Hamad Al Khalifa owns the rights to the grand prix and serves as commander of the armed forces. Although the F1 race is the island's premier international event, many Bahrainis see it as a regime vanity project.

Last year's race was cancelled after the authorities imposed martial law and launched a punishing crackdown on dissent. Hundreds have been tried on anti-state charges in a special security court, including more than 100 athletes, coaches and sports officials. Dozens have been sentenced to prison terms, including a prominent human rights activist who is serving a life sentence for his role in the uprising.

The activist Abdulhadi al-Khawaja has been on hunger strike for more than 50 days. Opposition supporters rally every day for his release, often carrying his picture along with posters calling for the cancellation of the F1 race. Human rights organisations have warned Bahraini authorities that al-Khawaja may die and appealed to those involved in the race to stay away.

"It is impossible to imagine that the Bahrain Grand Prix will go ahead if Abdulhadi al-Khawaja dies on hunger strike in prison," said Mary Lawlor, the executive director of an Ireland-based rights organisation, Front Line Defenders. "The Bahraini authorities clearly want to present an image of business as usual but their seeming indifference to the plight of Abdulhadi risks tragic consequences."

In February, an opposition group that has been the driving force of the year-long uprising warned the F1 boss, Bernie Ecclestone, against staging the Bahrain race "at a time when children are being killed in the streets". The grand prix's return to the Gulf kingdom would "imprint it with the image of death and human rights violations", the group said.

Race organisers, however, remain committed to staging the grand prix, which draws a worldwide TV audience of around 100 million in 187 countries. The annual race has been Bahrain's most profitable international event since 2004, when it became the first Arab country to stage a grand prix.

The F1 world champions Sebastian Vettel and Michael Schumacher have backed the decision to go ahead with the Bahrain GP. Ecclestone has also dismissed opposition to the race , describing it as "all nonsense" after lunching with Bahrain international circuit executives in London last week. "Of course the race is going to happen," he said. "No worries at all."

Peace and Freedom Before a Grand Prix in Bahrain

FRIDAY, APRIL 6, 2012

Peace and Freedom Before a Grand Prix in Bahrain

The 2012 Bahrain Grand Prix is scheduled for later this month. There are calls to cancel it, here's why. For a change, I drew a cartoon instead of writing a blog.
"It is impossible to imagine that the Bahrain Grand Prix will go ahead if Abdulhadi Alkhawaja dies on hunger strike in prison,” said Mary Lawlor, Executive Director of Front Line Defenders in Manama.

SUNDAY, APRIL 8, 2012 Schapelle Corby - A Formal Complaint To The NSW Police Integrity Commission, Re New Information on NSW Police Corruption, CC Justice David Levine

SUNDAY, APRIL 8, 2012

Schapelle Corby - A Formal Complaint To The NSW Police Integrity Commission, Re New Information on NSW Police Corruption, CC Justice David Levine


Click on the image to enlarge and read.

Dear Commissioner of the NSW Police Integrity Commission, Bruce James,

This is a new, formal complaint to your organisation re serious NSW Police Corruption. Please treat it as such.

I also note you personally sentenced the former Assistant Commissioner to the NSW Crime Commission, Mark Standen - so I guess you have some detailed knowledge of these issues?

My last, very detailed complaint on these matters was dismissed out of hand by your organisation - so I'm now asking you to look at them again, because minutes of a 17 October 2005 high level police meetingprove the NSW Crime Commission (including Mark Standen) andthe NSW Police, knew Schapelle was innocent, knew who the perpetrators were and knew baggage handlers were stashing illegal drugs in the bags of unwitting passengers. And who knows what further information will be released? You can find the flyer here, the poster here and full report here.

They did not make this information public, they did not give it to Schapelle's legal team - and they did not pursue the perpetrators. Quite apart from the horrific implications this has had for Schapelle, need I remind you of the 1988 Lockerbie aviation disaster, and thus your extremely grave responsibilities in this matter? I guess (in some ways), Schapelle and all the passengers she was travelling with were extremely lucky - because her illegally (and corruptly), unscreened bag only contained 4.2 kilos of marijuana, and not 4.2 kilos of semtex.

Could you also please investigate (and report on), the secret 30-page document that was presented during Christopher John Laycock's secret trial. Was it his "Insurance," naming other corrupt cops - and thus ensuring the relatively light sentence he received, considering the seriousness of his crimes? Are those named police officers still employed, and thus a gross danger to all members of the public they come in contact with?

I a similar vein, could you please investigate the information "Tom" provided to the court - as documented here. Was the nearly $1.6 million of public money he was paid the price of his silence, keeping the corrupt officers he named in high office? Was Mark Standen on that list (amongst others)?

I look forward to your public response to these issues Bruce - taking into account the recent observations I made to the Federal Member for Page about last Saturday's high profile piece in the Gold Coast Bulletin exposing these issues, and taking into account you don't know what cat will jump out of the bag next.

Regards, Kim
POSTED BY KIM AT 7:22 PM

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