Tag Archives: University of Oxford

University of Oxford (UK)’s wider aspects of nanotechnology online course

Despite its designation as a summer school programme, this University of Oxford’s online nanotechnology course is being offered from Oct. 13 – Nov. 30, 2014. Here’s more from the University of Oxford, Dept. of Continuing Studies, The Wider Contest of Nanotechnology webpage,

Overview

Nanotechnology is the identification, application and use of novel behaviour that occurs at the nanoscale to solve real-world problems. The discipline requires a breadth of understanding that is much wider than just the equations and scientific principles that underlie that behaviour. This introductory course gives an overview of the current state of nanotechnology as well as introducing the implications of these new technologies for safety, regulation, and innovation. The course provides an overview of the societal and environmental implications of nanotechnology.

The Wider Context of Nanotechnology online course can be taken alone, with or without academic credit, or as part of the Postgraduate Certificate in Nanotechnology.

The result has been a high degree of confusion at all levels of society as to the ethics, safety and business implications of this emerging series of technologies. The course addresses these issues and others in emphasising the interdisciplinary nature of nanotechnology. This is important because students who specialise in nanotechnology must be trained to appreciate a range of issues beyond the confines of pure science. Nanotechnology has applications in a broad range of fields and sectors of society. A student trained in electrical engineering, for example, who goes on to specialise in nanotechnology, may undertake a research project developing nanosensors that will be implanted in human subjects. He or she will therefore need to develop new skills to appreciate the broader ethical, societal and environmental implications of such research.

The development of interdisciplinary skills involves not only learning methods of reasoning and critical thinking, but also gaining experience with the dynamics and development of effective multi-disciplinary function. Technologists must become comfortable addressing various issues as an integral part of doing advanced research in a team that might draw upon the expertise of not only engineers, but also biologists, doctors, lawyers and business people. As the project evolves knowledge of the place of nanotechnology in business becomes increasingly important. This course teaches an understanding of the basic workings of how nanotechnology innovation is exploited, together with an understanding of the dynamics of entrepreneurship

Here are some details about the Programme Director and Tutor,

Dr Christiane Norenberg

Role: Director

Christiane is the Nanotechnology HEIF Manager at the University of Oxford’s Begbroke Science Park. She received her DPhil in Materials Science from the University of Oxford in 1998 and continued with postdoctoral research. In 2001, Christiane was awarded the Royal Society Dorothy Hodgkin Fellowship for her work on the growth and characterisation of nanostructures on semiconductor surfaces. After a period as a lecturer at the Multidisciplinary Nanotechnology Centre at Swansea University, Christiane returned to Oxford in 2007 to take up her present post.

Her interests and expertise are in the areas of surface science, growth and characterisation of nanostructures on surfaces, and nanotechnology in general. Christiane also teaches nanoscience and materials science at undergraduate and postgraduate level.

Dr Keith Simons

Role: Tutor

Dr Keith Simons, a chemist by training, is an independent innovation consultant who works as an interim manager in business development and fundraising for high-technology start-up organisations. He also works for regional, national and European governments in evaluation and monitoring of publicly-funded research. Keith is also the tutor for our first course to feature Adobe Connect Professional, the Postgraduate Certificate in Nanotechnology.

He has previously been the Business Development Manager for the Crystal Faraday Partnership, a not-for-profit organisation, backed by the British government and responsible for advancing innovation in Green Chemical Technologies for the chemical and allied industries. Prior to Crystal Faraday, he worked for Avantium Technologies in Amsterdam, a start-up company that developed high throughput technologies for the chemicals and pharmaceutical industries. This built upon his experience as development chemist at Johnson Matthey in the UK where he developed accelerated techniques for catalyst development and process optimisation for pharmaceutical manufacture.

Keith has degrees from the Universities of Hull and Liverpool. He has also performed postdoctoral research at the ETH, Zurich.

I notice Dr. Norenberg received a ‘Dorothy Hodgkin’ fellowship. Coincidentally, I mentioned a play about Dorothy Hodgkin and her friendship with Margaret Thatcher (Hodgkin’s former student and a UK Prime Minister) to be broadcast on BBC 4 later this week on Aug. 20, 2014. Scroll down about 50% of the way if you want to read my Aug. 15, 2014 posting about the play and other arts and sciences news.

Getting back to the wider implications of nanotechnology, the course fee is £2400.00 and it is possible to apply for scholarships and other financial assistance.

Wearable solar panels with perovskite

There was a bit of a flutter online in late July 2014 about solar cell research and perovskite, a material that could replace silicon therefore making solar cells more affordable, which hopefully would lead to greater adoption of the technology. Happily, the publishers of the study seem to have reissued their news release (h/t Aug. 11, 2014 news item on Nanwerk).

From the Wiley online press release Nr. 29/2014,

Textile solar cells are an ideal power source for small electronic devices incorporated into clothing. In the journal Angewandte Chemie, Chinese scientists have now introduced novel solar cells in the form of fibers that can be woven into a textile. The flexible, coaxial cells are based on a perovskite material and carbon nanotubes; they stand out due to their excellent energy conversion efficiency of 3.3 % and their low production cost.

The dilemma for solar cells: they are either inexpensive and inefficient, or they have a reasonable efficiency and are very expensive. One solution may come from solar cells made of perovskite materials, which are less expensive than silicon and do not require any expensive additives. Perovskites are materials with a special crystal structure that is like that of perovskite, a calcium titanate. These structures are often semiconductors and absorb light relatively efficiently. Most importantly, they can move electrons excited by light for long distances within the crystal lattice before they return to their energetic ground state and take up a solid position – a property that is very important in solar cells.

A team led by Hisheng Peng at Fudan University in Shanghai has now developed perovskite solar cells in the form of flexible fibers that can be woven into electronic textiles. Their production process is relatively simple and inexpensive because it uses a solution-based process to build up the layers.

The anode is a fine stainless steel wire coated with a compact n-semiconducting titanium dioxide layer. A layer of porous nanocrystalline titanium dioxide is deposited on top of this. This provides a large surface area for the subsequent deposition of the perovskite material CH3NH3PbI3. This is followed by a layer made of a special organic material. Finally a transparent layer of aligned carbon nanotubes is continuously wound over the whole thing to act as the cathode. The resulting fiber is so fine and flexible that it can be woven into textiles.

The perovskite layer absorbs light, that excites electrons and sets them free, causing a charge separation between the electrons and the formally positively charged “holes” The electrons enter the conducting band of the compact titanium dioxide layer and move to the anode. The “holes” are captured by the organic layer. The large surface area and the high electrical conductivity of the carbon nanotube cathode aid in the rapid conduction of the charges with high photoelectric currents. The fiber solar cell can attain an energy conversion efficiency of 3.3 %, exceeding that of all previous coaxial fiber solar cells made with either dyes or polymers.

Here’s an image used in the press release illustrating the new fiber,

[downloaded from http://www.wiley-vch.de/vch/journals/2002/press/201429press.pdf]

[downloaded from http://www.wiley-vch.de/vch/journals/2002/press/201429press.pdf]

Here’s a link to and a citation for the paper,

Integrating Perovskite Solar Cells into a Flexible Fiber by Longbin Qiu, Jue Deng, Xin Lu, Zhibin Yang, and Prof. Huisheng Peng. Angewandte Chemie International Edition DOI: 10.1002/anie.201404973 Article first published online: 22 JUL 2014

© 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

This paper is behind a paywall.

I found a second item about perovskite and solar cells in a May 16, 2014 article by Vicki Marshall for Chemistry World which discussed some research in the UK (Note: Links have been removed),

A lead-free and non-toxic alternative to current perovskite solar-cell technology has been reported by researchers in the UK: tin halide perovskite solar cells. They are also cheaper to manufacture than the silicon solar cells currently dominating the market.

Nakita Noel, part of Henry Snaith’s research team at the University of Oxford, describes how perovskite materials have caused a bit of a whirlwind since they came out in 2009: ‘Everybody that’s working in the solar community is looking to beat silicon.’ Despite the high efficiency of conventional crystalline silicon solar cells (around 20%), high production and installation costs decrease their economic feasibility and widespread use.

The challenge to find a cheaper alternative led to the development of perovskite-based solar cells, as organic–inorganic metal trihalide perovskites have both abundant and cheap starting materials. However, the presence of lead in some semiconductors could create toxicology issues in the future. As Noel puts it ‘every conference you present at somebody is bound to put up their hand and ask “What about the lead – isn’t this toxic?”’

Brian Hardin, co-founder of PLANT PV, US, and an expert in new materials for photovoltaic cells, says the study ‘should be considered a seminal work on alternative perovskites and is extremely valuable to the field as they look to better understand how changes in chemistry affect solar cell performance and stability.’

Here’s a link to and a citation for the UK researchers’ paper,

Lead-free organic–inorganic tin halide perovskites for photovoltaic applications by Nakita K. Noel, Samuel D. Stranks, Antonio Abate, Christian Wehrenfennig, Simone Guarnera, Amir-Abbas Haghighirad, Aditya Sadhana, Giles E. Eperon, Sandeep K. Pathak, Michael B. Johnston, Annamaria Petrozza, Laura M. Herza, and Henry J. Snaith. Energy Environ. Sci., 2014, Advance Article DOI: 10.1039/C4EE01076K First published online 01 May 2014

This article was open access until June 27, 2014 but now it is behind a paywall.

I notice there’s no mention of lead in the materials describing the research paper from the Chinese scientists. Perhaps they were working with lead-free materials.

The age of the ‘nano-pixel’

As mentioned here before, ‘The Diamond Age: Or, A Young Lady’s Illustrated Primer’, a 1985 novel by Neal Stephenson featured in its opening chapter a flexible, bendable, rollable, newspaper screen. It’s one of those devices promised by ‘nano evangelists’ that never quite seems to come into existence. However, ‘hope springs eternally’ as they say and a team from the University of Oxford claims to be bringing us one step closer.

From a July 10, 2014 University of Oxford press release (also on EurekAlert but dated July 9, 2014 and on Azoanano as a July 10, 2014 news item),

A new discovery will make it possible to create pixels just a few hundred nanometres across that could pave the way for extremely high-resolution and low-energy thin, flexible displays for applications such as ‘smart’ glasses, synthetic retinas, and foldable screens.

A team led by Oxford University scientists explored the link between the electrical and optical properties of phase change materials (materials that can change from an amorphous to a crystalline state). They found that by sandwiching a seven nanometre thick layer of a phase change material (GST) between two layers of a transparent electrode they could use a tiny current to ‘draw’ images within the sandwich ‘stack’.

Here’s a series of images the researchers have created using this technology,

Still images drawn with the technology: at around 70 micrometres across each image is smaller than the width of a human hair.  Courtesy University of Oxford

Still images drawn with the technology: at around 70 micrometres across each image is smaller than the width of a human hair. Courtesy University of Oxford

The press release offers a technical description,

Initially still images were created using an atomic force microscope but the team went on to demonstrate that such tiny ‘stacks’ can be turned into prototype pixel-like devices. These ‘nano-pixels’ – just 300 by 300 nanometres in size – can be electrically switched ‘on and off’ at will, creating the coloured dots that would form the building blocks of an extremely high-resolution display technology.

‘We didn’t set out to invent a new kind of display,’ said Professor Harish Bhaskaran of Oxford University’s Department of Materials, who led the research. ‘We were exploring the relationship between the electrical and optical properties of phase change materials and then had the idea of creating this GST ‘sandwich’ made up of layers just a few nanometres thick. We found that not only were we able to create images in the stack but, to our surprise, thinner layers of GST actually gave us better contrast. We also discovered that altering the size of the bottom electrode layer enabled us to change the colour of the image.’

The layers of the GST sandwich are created using a sputtering technique where a target is bombarded with high energy particles so that atoms from the target are deposited onto another material as a thin film.

‘Because the layers that make up our devices can be deposited as thin films they can be incorporated into very thin flexible materials – we have already demonstrated that the technique works on flexible Mylar sheets around 200 nanometres thick,’ said Professor Bhaskaran. ‘This makes them potentially useful for ‘smart’ glasses, foldable screens, windshield displays, and even synthetic retinas that mimic the abilities of photoreceptor cells in the human eye.’

Peiman Hosseini of Oxford University’s Department of Materials, first author of the paper, said: ‘Our models are so good at predicting the experiment that we can tune our prototype ‘pixels’ to create any colour we want – including the primary colours needed for a display. One of the advantages of our design is that, unlike most conventional LCD screens, there would be no need to constantly refresh all pixels, you would only have to refresh those pixels that actually change (static pixels remain as they were). This means that any display based on this technology would have extremely low energy consumption.’

The research suggests that flexible paper-thin displays based on the technology could have the capacity to switch between a power-saving ‘colour e-reader mode’, and a backlit display capable of showing video. Such displays could be created using cheap materials and, because they would be solid-state, promise to be reliable and easy to manufacture. The tiny ‘nano-pixels’ make it ideal for applications, such as smart glasses, where an image would be projected at a larger size as, even enlarged, they would offer very high-resolution.

Professor David Wright of the Department of Engineering at the University of Exeter, co-author of the paper, said: ‘Along with many other researchers around the world we have been looking into the use of these GST materials for memory applications for many years, but no one before thought of combining their electrical and optical functionality to provide entirely new kinds of non-volatile, high-resolution, electronic colour displays – so our work is a real breakthrough.’

The phase change material used was the alloy Ge2Sb2Te5 (Germanium-Antimony-Tellurium or GST) sandwiched between electrode layers made of indium tin oxide (ITO).

I gather the researchers are looking for investors (from the press release),

Whilst the work is still in its early stages, realising its potential, the Oxford team has filed a patent on the discovery with the help of Isis Innovation, Oxford University’s technology commercialisation company. Isis is now discussing the displays with companies who are interested in assessing the technology, and with investors.

Here’s a link to and a citation for the paper,

An optoelectronic framework enabled by low-dimensional phase-change films by Peiman Hosseini, C. David Wright, & Harish Bhaskaran. Nature 511, 206–211 (10 July 2014) doi:10.1038/nature13487 Published online 09 July 2014

This paper is behind a paywall.

Music on the web, a spider’s web, that is

I was expecting to see Markus Buehler and MIT (Massachusetts Institute of Technology) mentioned in this latest work on spiderwebs and music. Surprise! This latest research is from three universities in the UK as per a June 3, 2014 news item on ScienceDaily,

Spider silk transmits vibrations across a wide range of frequencies so that, when plucked like a guitar string, its sound carries information about prey, mates, and even the structural integrity of a web.

The discovery was made by researchers from the Universities of Oxford, Strathclyde, and Sheffield who fired bullets and lasers at spider silk to study how it vibrates. They found that, uniquely, when compared to other materials, spider silk can be tuned to a wide range of harmonics. The findings, to be reported in the journal Advanced Materials, not only reveal more about spiders but could also inspire a wide range of new technologies, such as tiny light-weight sensors.

A June 3, 2014 University of Oxford news release (also on EurekAlert), which originated the news item, explains the research and describes how it was conducted (firing bullets?),

‘Most spiders have poor eyesight and rely almost exclusively on the vibration of the silk in their web for sensory information,’ said Beth Mortimer of the Oxford Silk Group at Oxford University, who led the research. ‘The sound of silk can tell them what type of meal is entangled in their net and about the intentions and quality of a prospective mate. By plucking the silk like a guitar string and listening to the ‘echoes’ the spider can also assess the condition of its web.’

‘Most spiders have poor eyesight and rely almost exclusively on the vibration of the silk in their web for sensory information,’ said Beth Mortimer of the Oxford Silk Group at Oxford University, who led the research. ‘The sound of silk can tell them what type of meal is entangled in their net and about the intentions and quality of a prospective mate. By plucking the silk like a guitar string and listening to the ‘echoes’ the spider can also assess the condition of its web.’

This quality is used by the spider in its web by ‘tuning’ the silk: controlling and adjusting both the inherent properties of the silk, and the tensions and interconnectivities of the silk threads that make up the web. To study the sonic properties of the spider’s gossamer threads the researchers used ultra-high-speed cameras to film the threads as they responded to the impact of bullets. [emphasis mine] In addition, lasers were used to make detailed measurements of even the smallest vibration.

‘The fact that spiders can receive these nanometre vibrations with organs on each of their legs, called slit sensillae, really exemplifies the impact of our research about silk properties found in our study,’ said Dr Shira Gordon of the University of Strathclyde, an author involved in this research.

‘These findings further demonstrate the outstanding properties of many spider silks that are able to combine exceptional toughness with the ability to transfer delicate information,’ said Professor Fritz Vollrath of the Oxford Silk Group at Oxford University, an author of the paper. ‘These are traits that would be very useful in light-weight engineering and might lead to novel, built-in ‘intelligent’ sensors and actuators.’

Dr Chris Holland of the University of Sheffield, an author of the paper, said: ‘Spider silks are well known for their impressive mechanical properties, but the vibrational properties have been relatively overlooked and now we find that they are also an awesome communication tool. Yet again spiders continue to impress us in more ways than we can imagine.’

Beth Mortimer said: ‘It may even be that spiders set out to make a web that ‘sounds right’ as its sonic properties are intimately related to factors such as strength and flexibility.’

The research paper has not yet been published in Advanced Materials (I checked this morning, June 4, 2014).

However, there is this video from the researchers,

As for Markus Buehler’s work at MIT, you can find out more in my Nov. 28, 2012 posting, Producing stronger silk musically.

Isis Innovation (University of Oxford, UK) spins out buckyball company, Designer Carbon Materials

Buckyballs are also known as Buckminsterfullerenes. The name is derived from Buckminster Fuller who designed something he called geodesic domes, from the Wikipedia entry (Note: Links have been removed),

Buckminsterfullerene (or bucky-ball) is a spherical fullerene molecule with the formula C60 [C = carbon; 60 is the number of carbon atoms in the molecule]. It has a cage-like fused-ring structure (truncated icosahedron) which resembles a soccer ball, made of twenty hexagons and twelve pentagons, with a carbon atom at each vertex of each polygon and a bond along each polygon edge.

It was first generated in 1985 by Harold Kroto, James R. Heath, Sean O’Brien, Robert Curl, and Richard Smalley at Rice University.[2] Kroto, Curl and Smalley were awarded the 1996 Nobel Prize in Chemistry for their roles in the discovery of buckminsterfullerene and the related class of molecules, the fullerenes. The name is a reference to Buckminster Fuller, as C60 resembles his trademark geodesic domes. Buckminsterfullerene is the most commonly naturally occurring fullerene molecule, as it can be found in small quantities in soot.[3][4] Solid and gaseous forms of the molecule have been detected in deep space.[5]

Here’s a model of a buckyball,

Courtesy: Isis Innovation (Oxford University)

Courtesy: Isis Innovation (Oxford University)

An April 15, 2014 University of Oxford (Isis Innovation) news release (h/t phys.org) describes the news research and some technical details while avoiding any mention of how they’ve tackled the production problems (a major issue, which has seriously constrained their commercial use),

The firm, Designer Carbon Materials, has been established by Isis Innovation, the University of Oxford’s technology commercialisation company, and will cost-effectively manufacture commercially useful quantities of the spherical carbon cage structures. Designer Carbon Materials is based on research from Dr Kyriakos Porfyrakis of Oxford University’s Department of Materials.

‘It is possible to insert a variety of useful atoms or atomic clusters into the hollow interior of these ball-like molecules, giving them new and intriguing abilities. Designer Carbon Materials will focus on the production of these value-added materials for a range of applications,’ said Dr Porfyrakis.

‘For instance, fullerenes are currently used as electron acceptors in polymer-based solar cells achieving some of the highest power conversion efficiencies known for these kinds of solar cells. Our endohedral fullerenes are even better electron-acceptors and therefore have the potential to lead to efficiencies exceeding 10 per cent.

‘The materials could also be developed as superior MRI contrast agents for medical imaging and as diagnostics for Alzheimer’s and Parkinson’s, as they are able to detect the presence of superoxide free radical molecules which may cause these conditions. We are receiving fantastic interest from organisations developing these applications, who until now have been unable to access useful quantities of these materials.’

The manufacturing process, patented by Isis Innovation, will continue to be developed by Designer Carbon Materials as it also makes its first sales of these extremely high-value materials.

Tom Hockaday, managing director of Isis Innovation, said: ‘This is a great example of an Isis spin-out which is both looking at exciting future applications for its technology and also answering a real market need. There is already significant demand for these nanomaterials and we expect the first customer orders will be fulfilled over the next few months.’

Investment in the company has been led by Oxford Technology Management and the Oxford Invention Fund. Lucius Carey from Oxford Technology Management said: ‘We are delighted to be investing in Designer Carbon Materials. The purposes of the investment will be to move into commercial premises and to scale up.’

Isis Innovation is a University of Oxford initiative and you can find out more about Isis Innovation here. As for the new spin-out company, Designer Carbon Materials, they have no website that I’ve been able to find but there is this webpage on the Isis Innovation website.

Oxford’s 2014 Nanotechnology Summer School

Here’s some information about Oxford’s sixth annual nanotechnology summer programme from a March 25, 2014 news item on Nanowerk (Note: A link has been removed),

The theme of the sixth annual Oxford Nanotechnology Summer School in 2014 will be ‘An Introduction to Bionanotechnology’.

Each year Oxford’s Nanotechnology Summer School focuses on applications of nanotechnologies in a different field. Comprising presentations from leading researchers and practitioners from the University of Oxford and beyond, the Nanotechnology Summer School is essential for anyone with an interest in these topics.

There’s more about the summer school on the University of Oxford’s Nanotechnology Summer School 2014′s course page,

This five-day intensive course provides a thorough introduction to the exciting and emerging field of bionanotechnology. Each of the five days of the Nanotechnology Summer School has a dedicated theme and is led by key researchers in the field. The course will be valuable to those seeking an introduction to current research and applications in the subject.

The first day of the Summer School gives an introduction to cell biology and bionanotechnology. The following four days focus on bioanalytical techniques; applied genomics and proteomics; nanoparticles, nanostructures and biomimetics; and the interaction of nanomaterials with biological systems, respectively.

The full Summer School programme will be as follows:

For those who like to know about the costs and attendance options (from the course page),

Payment

Summer School fees include electronic course materials, tuition, refreshments and three-course lunches. The price does not include accommodation. All courses are VAT exempt. There may also be some social events on certain days of the Summer School.

Student discounts

We offer a discounted fee to students in higher education. The student fee rate for five days of the Nanotechnology Summer School is £680.00. It is not possible to enrol online if you wish to take the course at a discounted rate. To apply at the discounted rate, please contact us for details: email [email protected].

Alumni Card-holders discount

Alumni Card-holders benefit from a 10% discount* on the Nanotechnology Summer School. If you wish to enrol, please remember to quote the code given in e-Pidge to ensure you receive your discount.

* This offer is subject to availability, cannot be used retrospectively or in conjunction with any other offers or concessions available from either the University of Oxford or the Department for Continuing Education.

Fee options

Programme Fee
Five Days – Standard Fee: £1340.00
Five Days – Student Fee: £680.00
One Day – Standard Rate: £295.00
One Day – Student Rate: £150.00

Here’s how you can apply,

Please note that we cannot accept applications from those who are under 18 years of age.

You can apply for this course in the following ways:

Apply online
enrol onlineto secure your place on this course now
Apply by post, email or fax
PDF application form PDF document.

Terms and Conditions (important: please read before applying) .
Guidance Notes (important: please read before applying) PDF document.

Good luck1

Finding a successor to graphene

The folks at the Lawrence Berkeley National Laboratory (Berkeley Lab) have announced a ‘natural’ 3D counterpart of graphene in a Jan. 16, 2014 Berkeley Lab news release (also on EurekAlert and on Azonano dated Jan. 17, 2014),

The discovery of what is essentially a 3D version of graphene – the 2D sheets of carbon through which electrons race at many times the speed at which they move through silicon – promises exciting new things to come for the high-tech industry, including much faster transistors and far more compact hard drives. A collaboration of researchers at the U.S Department of Energy (DOE)’s Lawrence Berkeley National Laboratory (Berkeley Lab) has discovered that sodium bismuthate can exist as a form of quantum matter called a three-dimensional topological Dirac semi-metal (3DTDS). This is the first experimental confirmation of 3D Dirac fermions in the interior or bulk of a material, a novel state that was only recently proposed by theorists.

The news release provides a description of graphene and the search for alternatives (counterparts),

Two of the most exciting new materials in the world of high technology today are graphene and topological insulators, crystalline materials that are electrically insulating in the bulk but conducting on the surface. Both feature 2D Dirac fermions (fermions that aren’t their own antiparticle), which give rise to extraordinary and highly coveted physical properties. Topological insulators also possess a unique electronic structure, in which bulk electrons behave like those in an insulator while surface electrons behave like those in graphene.

“The swift development of graphene and topological insulators has raised questions as to whether there are 3D counterparts and other materials with unusual topology in their electronic structure,” says Chen [Yulin Chen, a physicist from the University of Oxford who led this study working with Berkeley Lab’s Advanced Light Source (ALS)]. “Our discovery answers both questions. In the sodium bismuthate we studied, the bulk conduction and valence bands touch only at discrete points and disperse linearly along all three momentum directions to form bulk 3D Dirac fermions. Furthermore, the topology of a 3DTSD electronic structure is also as unique as those of topological insulators.”

I’m a bit puzzled as to how this new material can be described as “essentially a 3D version of graphene” as my understanding is that graphene must be composed of carbon and have a 2-dimensiional honeycomb structure to merit the name. In any event, this new material, sodium bismuthate, has some disadvantages but the discovery is an encouraging development (from the news release),

Sodium bismuthate is too unstable to be used in devices without proper packaging, but it triggers the exploration for the development of other 3DTDS materials more suitable for everyday devices, a search that is already underway. Sodium bismuthate can also be used to demonstrate potential applications of 3DTDS systems, which offer some distinct advantages over graphene.

“A 3DTDS system could provide a significant improvement in efficiency in many applications over graphene because of its 3D volume,” Chen says. “Also, preparing large-size atomically thin single domain graphene films is still a challenge. It could be easier to fabricate graphene-type devices for a wider range of applications from 3DTDS systems.”

In addition, Chen says, a 3DTDS system also opens the door to other novel physical properties, such as giant diamagnetism that diverges when energy approaches the 3D Dirac point, quantum magnetoresistance in the bulk, unique Landau level structures under strong magnetic fields, and oscillating quantum spin Hall effects. All of these novel properties can be a boon for future electronic technologies. Future 3DTDS systems can also serve as an ideal platform for applications in spintronics.

While I don’t understand (again) the image the researchers have included as an illustration of their work, I do find the ‘blue jewels in a pile of junk’ very appealing,

Beamline 10.0.1 at Berkeley Lab’s Advanced Light Source is optimized for the study of for electron structures and correlated electron systems. (Photo by Roy Kaltschmidt) Courtesy: Berkeley Lab

Beamline 10.0.1 at Berkeley Lab’s Advanced Light Source is optimized for the study of for electron structures and correlated electron systems. (Photo by Roy Kaltschmidt) Courtesy: Berkeley Lab

Here’s a link to and a citation for the paper,

Discovery of a Three-dimensional Topological Dirac Semimetal, Na3Bi by Zhongkai Liu, Bo Zhou, Yi Zhang, Zhijun Wang, Hongming Weng, Dharmalingam Prabhakaran, Sung-Kwan Mo, Zhi-Xun Shen, Zhong Fang, Xi Dai, and Zahid Hussain. Published Online January 16 2014 Science DOI: 10.1126/science.1245085

This paper is behind a paywall.

Fly me to the moon using 17th century science

Apparently the first serious scientific thinking about space exploration (in Europe?) was written almost four hundred years ago by John Wilkins, a priest in the Church of England. This year, 2014, marks the four hundredth anniversary of Wilkins birth on January 1 and provides the occasion for a paper, Fly me to the moon? by Allan Chapman, historian and professor at Oxford University (UK).

From a Jan. 14, 2014 news item on ScienceDaily about this Jacobean space exploration programme,

The seventeenth century saw unprecedented changes in our understanding of the universe, spurred on by the invention of the telescope and the opportunity to study stars and planets in detail for the first time. Figures like Galileo are famous for their work not just in astronomy but in scientific experiments of many kinds that challenged established ideas and helped lead to the final demise of an Earth-centred view of the cosmos.

Now historian Prof. Allan Chapman of Wadham College, University of Oxford, has investigated a less well-known pioneer, John Wilkins, who was born 400 years ago this month. His achievements include a plan for ‘mechanical’ space travel, the popularisation of astronomy, managing to negotiate the politics and privations of the English Civil War and helping to found the Royal Society. Prof. Chapman will describe Wilkins’ life in a presentation at the Royal Astronomical Society on Friday 10 January [2014].

The January ?, 2014 Royal Astronomical Society press release, which originated the news item, adds some details about Wilkins,

John Wilkins was born in Canons Ashby, Northamptonshire, on 1 January 1614. A graduate of Magdalen Hall, Oxford, he was ordained as a priest in the Church of England, before travelling widely in the UK and to Germany to meet contemporary scholars. In 1638 he published ‘The Discovery of a New World’ and then in 1640 ‘A Discourse Concerning a New Planet’. The frontispiece of the later book shows his affinity for the Copernican model of the Solar system, with the Polish astronomer and Galileo both prominent. Just as significantly, the illustration shows the stars extending to infinity, rather than being in a then conventional ‘fixed sphere’ just beyond Saturn.

With the two works, Wilkins used clear, concise English to popularise a new understanding of the universe, arguing passionately against the theories of Aristotle that dated back 2000 years. He understood how these ancient ideas (for example that it was in the nature of heavy objects to fall, whereas light materials like smoke would rise) had been fundamentally undermined by scientific discoveries. The model of the cosmos had completely changed over the course of the century since Copernicus.

He [Chapman] sees John Wilkins as one of the first people to understand the power of mass communication for astronomy and as an intellectual ancestor of the late Sir Patrick Moore and Carl Sagan. “Wilkins was a pioneer of English language science communication. Anybody who could read the Bible or enjoy a Shakespeare play could relate to Wilkins’ vision of the new astronomy of Copernicus and Galileo.’

Remarkably, Wilkins also speculated on space travel in his 1640 work. He considered the problems of travel to the Moon, including overcoming the gravitational pull of the Earth, the coldness of space and what the ‘sky voyagers’ would eat during a journey that he thought would take about 180 days.

In 1648, after becoming Master of Wadham College in Oxford, Wilkins expanded these ideas in ‘Mathematical Magick’, a book which describes machines and how systems of gears, pulleys and springs make at first sight insurmountable tasks possible. There he discusses a ‘flying chariot’, a ship like vehicle with bird’s wings, powered by springs and gears that would carry the astronauts on their six month journey. Robert Hooke’s posthumous diary suggests that he and Wilkins may even have built a model of this aircraft. [emphasis mine]

Chapman comments, “John Wilkins was the first person to discuss space travel from a scientific and technological perspective rather than as an aspect of fantasy literature. In his writing he initiates a ‘Jacobean Space Programme’, a serious proposal for travelling to other worlds”.

Here’s an image Chapman has created to illustrate what he believes was Wilkins vision for space travel,

http://www.ras.org.uk/news-and-press/news-archive/254-news-2014/2380-the-jacobean-space-programme-the-life-of-john-wilkins [downloaded from http://www.ras.org.uk/news-and-press/news-archive/254-news-2014/2380-the-jacobean-space-programme-the-life-of-john-wilkins]

Wilkins and Robert Hooke fly to the Moon from Wadham College. Wilkins left no picture of his “Flying Chariot”, so Prof. Chapman assembled components from written descriptions into this drawing. Credit: A. Chapman.[downloaded from http://www.ras.org.uk/news-and-press/news-archive/254-news-2014/2380-the-jacobean-space-programme-the-life-of-john-wilkins]

As one might expect from an historian, Chapman contextualizes Wilkins’ accomplishments within the major political events of the day,

1642 saw the onset of the English Civil War, a conflict that led to the abolition of the Anglican Church, the beheading of King Charles I and the Archbishop of Canterbury and the ascendancy of Oliver Cromwell as Lord Protector. A consummate diplomat, Wilkins even managed to marry Cromwell’s sister, took on the post at Wadham after opponents of Cromwell were purged and yet made the College a centre of tolerance that hosted a club of scientists.

After the restoration of the monarchy in 1659, Wilkins was removed from his next post as Master of Trinity College, Cambridge but nonetheless went on to found and become Secretary of the Royal Society and was appointed Bishop of Chester in 1668. He died in 1671.

While it’s too late to attend Chapman’s Jan. 10, 2014 talk and there doesn’t seem to be an online video of the talk, there’s Chapman’s 6 pp. paper, Fly me to the moon? for anyone who want’s to know more.

New way to practice brain surgery skills before working on live patients

It’s a little disconcerting to learn that neurosurgeons don’t have many options to test drive their skills before they start practicing on patients as a Dec. 10, 2013 news release on EurekAlert about 3D printing (and a new way for neurosurgeons to practice) notes,,

Researchers from the University of Malaya in Malaysia, with collaboration from researchers from the University of Portsmouth and the University of Oxford in the United Kingdom, announce the creation of a cost-effective two-part model of the skull for use in practicing neurosurgical techniques. The model, produced using the latest generation of multimaterial 3D printers, is composed of a variety of materials that simulate the various consistencies and densities of human tissues encountered during neurosurgery. Details on the model are provided in “Utility of multimaterial 3D printers in creating models with pathological entities to enhance the training experience of neurosurgeons. Technical note.” By Vicknes Waran, F.R.C.S.(Neurosurgery), Vairavan Narayanan, F.R.C.S.(Neurosurgery), M.Surg., Ravindran Karuppiah, M.Surg., Sarah L. F. Owen, D.Phil., and Tipu Aziz, F.Med.Sci., published today [Dec. 10, 2013] online, ahead of print, in the Journal of Neurosurgery.

Here’s the disconcerting part (from the news release),

Neurosurgery is a difficult discipline to master. Trainees may spend as many as 10 years after graduation from medical school developing and honing their surgical skills before they can be designated as proficient in their specialty. The greater the number and variety of neurosurgical training sessions, the better the training experience. However, the authors point out that it is difficult to find suitable simulation models that offer accuracy and realism for neurosurgical training while keeping training costs down.

The news release provides a description of what makes the current generation of 3D printers particularly attractive for creating practice skulls, etc.,

Three-dimensional printers have been used to create models of normal and pathological human tissues and organs for physician training and patient instruction for some time. Until recently, however, only one material could be used in the creation of models. While useful for display purposes, one-material models have little value for hands-on training. With the advent of multimaterial 3D printers, the sophistication and versatility of the new models that could be created increased substantially, but so did their price.

Waran and colleagues tell us that this situation is now changing. They state that the newest generation of multimaterial 3D printers can aid neurosurgical training by creating models that simulate different diseases in a variety of body tissues, and they can do this in a cost-effective manner.

With the aid of an Objet500 Connex™ multimaterial 3D printer (Stratasys, Ltd.), researchers at the University of Malaya created a two-part model that can simulate pathological conditions in actual patients. The base piece of the model (the “head”) consists of one material. It has human features (a “face”) and the natural contours of a human skull. This piece is used to train the novice in neuronavigation techniques and can be reused again and again. The second part of the model defines the region in which simulated surgery is performed. This piece contains several different materials, which separately simulate skin, bone, dura mater, tumor, and normal brain tissue. The second piece fits into a slot in the base piece; this multi-textured piece can only be used once and is discarded after the practice session. Fortunately, it is easy to reproduce a steady stream of new pieces.

To make the training session valuable, the trainee must be able to see, feel, and even hear different “tissue” responses to surgical instruments and techniques during simulation surgery. The researchers tell us that the “skin” is designed to be pliable enough to be cut by a scalpel and repaired by sutures, yet sturdy enough to be held by a retractor; the “bone” has to be hard enough for the trainee to obtain experience using bone perforators and cutters; the “dura mater” must be thin and pliable—just like the real thing. The consistency and color of the “tumor” differ from those of the “brain” to simulate actual tissues. The researchers made the “tumor” softer than the “brain” and colored it orange, whereas they colored the brain light yellow.

To test the quality of the model produced by the printer and to make minor adjustments, the researchers from Malaysia were aided by other researchers from the UK. Three neurosurgeons and one expert in surgical simulations performed simulated surgery and assessed the model’s “tissue” components. All parts received ratings of “fair” or “good,” with most rated “good.”

The usefulness of the model in training neuronavigation techniques was also assessed. Since the two-part model was based on data from a real patient, it was no surprise that “neuroimaging” was rated “excellent” by the evaluating team. Two navigation systems were used, and in both cases “registration was accurate and planning possible.”

Waran and colleagues state that the reusable base piece of the model costs approximately US $2000 to fabricate and the disposable inset costs US $600. This makes these training models affordable. In addition, model designs are based on actual patient data, providing limitless variety.

Here’s a link to and a citation for the paper,

Waran V, Narayana V, Karuppiah R, Owen SLF, Aziz T: Utility of multimaterial 3D printers in creating models with pathological entities to enhance the training experience of neurosurgeons. Technical note. Journal of Neurosurgery, published online, ahead of print, December 10, 2013; DOI: 10.3171/2013.11.JNS131066.

This appears to be an open access paper.

Surviving 39 minutes at room temperature—recordbreaking for quantum materials

There are two news releases about this work which brings quantum computing a step closer to reality. I’ll start with the Nov. 15, 2013 Simon Fraser University (SFU; located in Vancouver, Canada) news release (Note: A link has been removed),,

An international team of physicists led by Simon Fraser University professor Mike Thewalt has overcome a key barrier to building practical quantum computers, taking a significant step to bringing them into the mainstream.

In their record-breaking experiment conducted on SFU’s Burnaby campus, [part of Metro Vancouver] the scientists were able to get fragile quantum states to survive in a solid material at room temperature for 39 minutes. For the average person, it may not seem like a long time, but it’s a veritable eternity to a quantum physicist.

“This opens up the possibility of truly long-term coherent information storage at room temperature,” explains Thewalt.

Quantum computers promise to significantly outperform today’s machines at certain tasks, by exploiting the strange properties of subatomic particles. Conventional computers process data stored as strings of ones or zeroes, but quantum objects are not constrained to the either/or nature of binary bits.

Instead, each quantum bit – or qubit – can be put into a superposition of both one and zero at the same time, enabling them to perform multiple calculations simultaneously. For instance, this ability to multi-task could allow quantum computers to crack seemingly secure encryption codes.

“A powerful universal quantum computer would change technology in ways that we already understand, and doubtless in ways we do not yet envisage,” says Thewalt, whose research was published in Science today.

“It would have a huge impact on security, code breaking and the transmission and storage of secure information. It would be able to solve problems which are impossible to solve on any conceivable normal computer. It would be able to model the behaviour of quantum systems, a task beyond the reach of normal computers, leading, for example, to the development of new drugs by a deeper understanding of molecular interactions.”

However, the problem with attempts to build these extraordinary number-crunchers is that superposition states are delicate structures that can collapse like a soufflé if nudged by a stray particle, such as an air molecule.

To minimize this unwanted process, physicists often cool their qubit systems to almost absolute zero (-273 C) and manipulate them in a vacuum. But such setups are finicky to maintain and, ultimately, it would be advantageous for quantum computers to operate robustly at everyday temperatures and pressures.

“Our research extends the demonstrated coherence time in a solid at room temperature by a factor of 100 – and at liquid helium temperature by a factor of 60 (from three minutes to three hours),” says Thewalt.

“These are large, significant improvements in what is possible.”

The November 15, 2013 University of Oxford news release (also on EurekAlert), features their own researcher and more information (e.g., the previous record for maintaining coherence of a solid state at room temperature),

An international team including Stephanie Simmons of Oxford University report in this week’s Science a test performed as part of a project led by Mike Thewalt of Simon Fraser University, Canada, and colleagues. …

In the experiment, the team raised the temperature of a system, in which information is encoded in the nuclei of phosphorus atoms in silicon, from -269°C to 25°C and demonstrated that the superposition states survived at this balmy temperature for 39 minutes – outside of silicon the previous record for such a state’s survival at room temperature was around two seconds. [emphasis mine] The team even found that they could manipulate the qubits as the temperature of the system rose, and that they were robust enough for this information to survive being ‘refrozen’ (the optical technique used to read the qubits only works at very low temperatures).

‘Thirty-nine minutes may not seem very long but as it only takes one-hundred-thousandth of a second to flip the nuclear spin of a phosphorus ion – the type of operation used to run quantum calculations – in theory over two million operations could be applied in the time it takes for the superposition to naturally decay by 1%. Having such robust, as well as long-lived, qubits could prove very helpful for anyone trying to build a quantum computer,’ said Stephanie Simmons of Oxford University’s Department of Materials, an author of the paper.

The team began with a sliver of silicon doped with small amounts of other elements, including phosphorus. Quantum information was encoded in the nuclei of the phosphorus atoms: each nucleus has an intrinsic quantum property called ‘spin’, which acts like a tiny bar magnet when placed in a magnetic field. Spins can be manipulated to point up (0), down (1), or any angle in between, representing a superposition of the two other states.

The team prepared their sample at just 4°C above absolute zero (-269°C) and placed it in a magnetic field. Additional magnetic field pulses were used to tilt the direction of the nuclear spin and create the superposition states. When the sample was held at this cryogenic temperature, the nuclear spins of about 37% of the ions – a typical benchmark to measure quantum coherence – remained in their superposition state for three hours. The same fraction survived for 39 minutes when the temperature of the system was raised to 25°C.

There is still some work ahead before the team can carry out large-scale quantum computations. The nuclear spins of the 10 billion or so phosphorus ions used in this experiment were all placed in the same quantum state. To run calculations, however, physicists will need to place different qubits in different states. ‘To have them controllably talking to one another – that would address the last big remaining challenge,’ said Simmons.

Even for the uninitiated, going from a record of two seconds to 39 minutes has to raise an eyebrow.

Here’s a link to and a citation for the paper,

Room-Temperature Quantum Bit Storage Exceeding 39 Minutes Using Ionized Donors in Silicon-28.by Kamyar Saeedi, Stephanie Simmons, Jeff Z. Salvail, Phillip Dluhy, Helge Riemann, Nikolai V. Abrosimov, Peter Becker, Hans-Joachim Pohl, John J. L. Morton, & Mike L. W. Thewalt.  Science 15 November 2013: Vol. 342 no. 6160 pp. 830-833 DOI: 10.1126/science.1239584

This paper is behind a paywall.

ETA Nov. 18 ,2013:  The University College of London has also issued a Nov. 15, 2013 news release on EurekAlert about this work. While some of this is repetitive, I think there’s enough new information to make this excerpt worthwhile,

The team even found that they could manipulate the qubits as the temperature of the system rose, and that they were robust enough for this information to survive being ‘refrozen’ (the optical technique used to read the qubits only works at very low temperatures). 39 minutes may not sound particularly long, but since it only takes a tiny fraction of a second to run quantum computations by flipping the spin of phosphorus ions (electrically charged phosphorus atoms), many millions of operations could be carried out before a system like this decays.

“This opens up the possibility of truly long-term coherent information storage at room temperature,” said Mike Thewalt (Simon Fraser University), the lead researcher in this study.

The team began with a sliver of silicon doped with small amounts of other elements, including phosphorus. They then encoded quantum information in the nuclei of the phosphorus atoms: each nucleus has an intrinsic quantum property called ‘spin’, which acts like a tiny bar magnet when placed in a magnetic field. Spins can be manipulated to point up (0), down (1), or any angle in between, representing a superposition of the two other states.

The team prepared their sample at -269 °C, just 4 degrees above absolute zero, and placed it in a magnetic field. They used additional magnetic field pulses to tilt the direction of the nuclear spin and create the superposition states. When the sample was held at this cryogenic temperature, the nuclear spins of about 37 per cent of the ions – a typical benchmark to measure quantum coherence – remained in their superposition state for three hours. The same fraction survived for 39 minutes when the temperature of the system was raised to 25 °C.