Tag Archives: Russia

Deriving graphene-like films from salt

This research comes from Russia (mostly). A July 29, 2016 news item on ScienceDaily describes a graphene-like structure derived from salt,

Researchers from Moscow Institute of Physics and Technology (MIPT), Skolkovo Institute of Science and Technology (Skoltech), the Technological Institute for Superhard and Novel Carbon Materials (TISNCM), the National University of Science and Technology MISiS (Russia), and Rice University (USA) used computer simulations to find how thin a slab of salt has to be in order for it to break up into graphene-like layers. Based on the computer simulation, they derived the equation for the number of layers in a crystal that will produce ultrathin films with applications in nanoelectronics. …

Caption: Transition from a cubic arrangement into several hexagonal layers. Credit: authors of the study

Caption: Transition from a cubic arrangement into several hexagonal layers. Credit: authors of the study

A July 29, 2016 Moscow Institute of Physics and Technology press release on EurekAlert, which originated the news item,  provides more technical detail,

From 3D to 2D

Unique monoatomic thickness of graphene makes it an attractive and useful material. Its crystal lattice resembles a honeycombs, as the bonds between the constituent atoms form regular hexagons. Graphene is a single layer of a three-dimensional graphite crystal and its properties (as well as properties of any 2D crystal) are radically different from its 3D counterpart. Since the discovery of graphene, a large amount of research has been directed at new two-dimensional materials with intriguing properties. Ultrathin films have unusual properties that might be useful for applications such as nano- and microelectronics.

Previous theoretical studies suggested that films with a cubic structure and ionic bonding could spontaneously convert to a layered hexagonal graphitic structure in what is known as graphitisation. For some substances, this conversion has been experimentally observed. It was predicted that rock salt NaCl can be one of the compounds with graphitisation tendencies. Graphitisation of cubic compounds could produce new and promising structures for applications in nanoelectronics. However, no theory has been developed that would account for this process in the case of an arbitrary cubic compound and make predictions about its conversion into graphene-like salt layers.

For graphitisation to occur, the crystal layers need to be reduced along the main diagonal of the cubic structure. This will result in one crystal surface being made of sodium ions Na? and the other of chloride ions Cl?. It is important to note that positive and negative ions (i.e. Na? and Cl?)–and not neutral atoms–occupy the lattice points of the structure. This generates charges of opposite signs on the two surfaces. As long as the surfaces are remote from each other, all charges cancel out, and the salt slab shows a preference for a cubic structure. However, if the film is made sufficiently thin, this gives rise to a large dipole moment due to the opposite charges of the two crystal surfaces. The structure seeks to get rid of the dipole moment, which increases the energy of the system. To make the surfaces charge-neutral, the crystal undergoes a rearrangement of atoms.

Experiment vs model

To study how graphitisation tendencies vary depending on the compound, the researchers examined 16 binary compounds with the general formula AB, where A stands for one of the four alkali metals lithium Li, sodium Na, potassium K, and rubidium Rb. These are highly reactive elements found in Group 1 of the periodic table. The B in the formula stands for any of the four halogens fluorine F, chlorine Cl, bromine Br, and iodine I. These elements are in Group 17 of the periodic table and readily react with alkali metals.

All compounds in this study come in a number of different structures, also known as crystal lattices or phases. If atmospheric pressure is increased to 300,000 times its normal value, an another phase (B2) of NaCl (represented by the yellow portion of the diagram) becomes more stable, effecting a change in the crystal lattice. To test their choice of methods and parameters, the researchers simulated two crystal lattices and calculated the pressure that corresponds to the phase transition between them. Their predictions agree with experimental data.

Just how thin should it be?

The compounds within the scope of this study can all have a hexagonal, “graphitic”, G phase (the red in the diagram) that is unstable in 3D bulk but becomes the most stable structure for ultrathin (2D or quasi-2D) films. The researchers identified the relationship between the surface energy of a film and the number of layers in it for both cubic and hexagonal structures. They graphed this relationship by plotting two lines with different slopes for each of the compounds studied. Each pair of lines associated with one compound has a common point that corresponds to the critical slab thickness that makes conversion from a cubic to a hexagonal structure energetically favourable. For example, the critical number of layers was found to be close to 11 for all sodium salts and between 19 and 27 for lithium salts.

Based on this data, the researchers established a relationship between the critical number of layers and two parameters that determine the strength of the ionic bonds in various compounds. The first parameter indicates the size of an ion of a given metal–its ionic radius. The second parameter is called electronegativity and is a measure of the ? atom’s ability to attract the electrons of element B. Higher electronegativity means more powerful attraction of electrons by the atom, a more pronounced ionic nature of the bond, a larger surface dipole, and a lower critical slab thickness.

And there’s more

Pavel Sorokin, Dr. habil., [sic] is head of the Laboratory of New Materials Simulation at TISNCM. He explains the importance of the study, ‘This work has already attracted our colleagues from Israel and Japan. If they confirm our findings experimentally, this phenomenon [of graphitisation] will provide a viable route to the synthesis of ultrathin films with potential applications in nanoelectronics.’

The scientists intend to broaden the scope of their studies by examining other compounds. They believe that ultrathin films of different composition might also undergo spontaneous graphitisation, yielding new layered structures with properties that are even more intriguing.

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

Ionic Graphitization of Ultrathin Films of Ionic Compounds by A. G. Kvashnin, E. Y. Pashkin, B. I. Yakobson, and P. B. Sorokin. J. Phys. Chem. Lett., 2016, 7 (14), pp 2659–2663 DOI: 10.1021/acs.jpclett.6b01214 Publication Date (Web): June 23, 2016

Copyright © 2016 American Chemical Society

This paper is behind a paywall.

Ageing population could drive progress in nanotechnology and robotics

A couple of theoreticians are proposing a generational gap as being a key source of conflict and technological process in the near future. From a July 27, 2016 news item on Nanotechnology Now,

The UN estimates that the number of people aged 65 and older will have reached almost a billion by 2030. The proportion of those aged over 80 will grow at particularly high rates, and their numbers are expected to reach 200 million by 2030 and triple that forty years later.

Due to a combination of an ageing population and declining birthrates, the demographic structure of most countries will change towards lower proportions of children and young people. As a result, the global division will no longer be between first- and third-world nations [also called developed and developing nations], but between old and young ones.

A July 25, 2016 National Research University Higher School of Economics [Russia] press release (also on EurekAlert), which originated the news item, expands on the theme,

According to the report of Senior Research Fellow of the HSE [Higher School of Economics] Laboratory for Monitoring the Risks of Socio-Political Destabilization Leonid Grinin and Senior Research Fellow of the International Centre for Education, Social and Humanitarian Studies Anton Grinin “Global Population Ageing and the Threat of Political Risks in the Light of Radical Technological Innovation in the Coming Decades.”, an increase in the number of older people will:

  • encourage societies facing workforce shortages to seek solutions to improve older people’s employability by helping them stay healthy, fit and full of energy for much longer than today;
  • encourage societies to focus more on rehabilitation of people with disabilities and provide them with new technology to support their employment;
  • encourage the development of labour-saving technologies, such as robotics, to assist caregivers;
  • lead to breakthroughs in medicine. Indeed, medical services will be the first to enter a new phase of technological revolution, radically changing the structure of production and people’s lives. Such a breakthrough will be associated what the authors call MANBRIC, i.e. a technological paradigm based on medicine, additive, nano- and bio- technologies, robotic, IT, and cognitive technologies;
  • boost government spending on healthcare, which today accounts for at least 10% of global GDP and can vary vastly across countries, e.g. reaching 17% in the U.S.;
  • promote the development of peripheral countries through higher spending on health care, leading to the emergence of a middle class, poverty reduction, literacy, and a better quality of life;
  • increase the demand for innovation and its financing from accumulated funds such as pensions and public allocations to medical and social needs;
  • lead to higher investment in supporting the health of ageing populations and the growing middle class.

Longevity Comes at a Cost

A confrontation between generations in the labor market and the weakening of democracy are the key risks associated with longer life expectancy.

Longer life spans and a lower proportion of young people in society may lead to the predominance of ‘third age’ voters. Politicians will need to tailor their messages to older and perhaps more conservative electorates. According to the researchers, “democracy can transform into a form of gerontocracy which may be hard to overcome; under such circumstances, competition for voters may lead to a crisis of democratic governance.”

A conflict between generations is another potential risk. As the retirement age increases, older employees will stay in the workforce longer – a situation which may hinder younger people’s careers and slow down technological progress.

A tendency towards gerontocracy has been particularly noticeable in Western Europe and the U.S., where democratic traditions are the strongest, but ethnic and cultural imbalances are increasingly visible. As a result, the U.S. may face confrontation between its younger Latinos and older white populations, and Europe may experience tensions between older white Christians and younger Muslims. Hence, globalization will inevitably cause such conflicts to transcend national borders and become global challenges.

I was not able to find the report mentioned in this release but I certainly would have liked to have looked at it. This redraws the conflict map in some interesting ways.

Researchers from Canada and Russia find metal-organic-frameworks in nature

To date, these ‘natural’ metal-organic-frameworks have been found only in Siberian coal mines. From an Aug, 5, 2016 news item on ScienceDaily,

One of the hottest new materials is a class of porous solids known as metal-organic frameworks, or MOFs. These human-made materials were introduced in the 1990s, and researchers around the world are working on ways to use them as molecular sponges for applications such as hydrogen storage, carbon sequestration, or photovoltaics.

Now, a surprising discovery by scientists in Canada and Russia reveals that MOFs also exist in nature — albeit in the form of rare minerals found so far only in Siberian coal mines.

The finding, published in the journal Science Advances, “completely changes the normal view of these highly popular materials as solely artificial, ‘designer’ solids,” says senior author Tomislav Friščić, an associate professor of chemistry at McGill University in Montreal. “This raises the possibility that there might be other, more abundant, MOF minerals out there.”

Caption: Individual crystals of synthetic zhemchuzhnikovite, prepared by Igor Huskić, McGill University. Credit: Igor Huskić, Friščić Research Group, McGill University

Caption: Individual crystals of synthetic zhemchuzhnikovite, prepared by Igor Huskić, McGill University. Credit: Igor Huskić, Friščić Research Group, McGill University

An Aug, 8, 2016 McGill University news release (also on EurekAlert but dated Aug. 5, 2016), which originated the news item, expands on the theme,

The twisting path to the discovery began six years ago, when Friščić came across a mention of the minerals stepanovite and zhemchuzhnikovite in a Canadian mineralogy journal. The crystal structure of the minerals, found in Russia between the 1940s and 1960s, hadn’t been fully determined. But the Russian mineralogists who discovered them had analyzed their chemical composition and the basic parameters of their structures, using a technique known as X-ray powder diffraction. To Friščić, those parameters hinted that the minerals could be structurally similar to a type of man-made MOF.

His curiosity piqued, Friščić began looking for samples of the rare minerals, reaching out to experts, museums and vendors in Russia and elsewhere. After a promising lead with a mining museum in Saint Petersburg failed to pan out, Igor Huskić, a graduate student in the Friščić research group at McGill turned his attention to synthesizing analogues of the minerals in the lab – and succeeded. But a major journal last year declined to publish the team’s work, in part because the original description of the minerals had been reported in a somewhat obscure Russian mineralogical journal.

Then, the McGill chemists caught a break: with the help of a crystallographer colleague in Venezuela, they connected with two prominent Russian mineralogists: Sergey Krivovichev, a professor at Saint Petersburg State University, and Prof. Igor Pekov of Lomonosov Moscow State University.

Krivovichev and Pekov were able to obtain the original samples of the two rare minerals, which had been found decades earlier in a coal mine deep beneath the Siberian permafrost. The Russian experts were also able to determine the crystal structures of the minerals. These findings confirmed the McGill researchers’ initial results from their lab synthesis.

Stepanovite and zhemchuzhnikovite have the elaborate, honeycomb-like structure of MOFs, characterized at the molecular level by large voids. The two minerals aren’t, however, representative of the hottest varieties of MOFs — those that are being developed for use in hydrogen-fueled cars or to capture waste carbon dioxide.

As a result, Friščić and his collaborators are now broadening their research to determine if other, more abundant minerals have porous structures that could make them suitable for uses such as hydrogen storage or even drug delivery.

In any event, the discovery of MOF structures in the two rare minerals already is “paradigm-changing” Friščić says. If scientists had been able to determine those structures in the 1960s, he notes, the development of MOF materials “might have been accelerated by 30 years.”

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

Minerals with metal-organic framework structures by Igor Huskić, Igor V. Pekov, Sergey V. Krivovichev, and Tomislav Friščić. Science Advances  05 Aug 2016: Vol. 2, no. 8, e1600621 DOI: 10.1126/sciadv.1600621

This paper appears to be open access.

The birth of carbon nanotubes (CNTs): a history

There is a comprehensive history of the carbon nanotube stretching back to prehistory and forward to recent times in a June 3, 2016 Nanowerk Spotlight article by C.K. Nisha and Yashwant Mahajan of the Center of Knowledge Management of Nanoscience & Technology (CKMNT) in India. The authors provide an introduction explaining the importance of CNTs,

Carbon nanotubes (CNTs) have been acknowledged as the material of the 21st century. They possess unique combination of extraordinary mechanical, electronic, transport, electrical and optical, properties and nanoscale sizes making them suitable for a variety of applications ranging from engineering, electronics, optoelectronics, photonics, space, defence industry, medicine, molecular and biological systems and so on and so forth. Worldwide demand for CNTs is increasing at a rapid pace as applications for the material are being matured.

According to MarketsandMarkets (M&M), the global market for carbon nanotubes in 2015 was worth about $2.26 billion1; an increase of 45% from 2009 (i.e. ~ $ 1.24 billion). This was due to the growing potential of CNTs in electronics, plastics and energy storage applications and the projected market of CNTs is expected to be around $ 5.64 billion in 2020.

In view of the scientific and technological potential of CNTs, it is of immense importance to know who should be credited for their discovery. In the present article, we have made an attempt to give a glimpse into the discovery and early history of this fascinating material for our readers. Thousands of papers are being published every year on CNTs or related areas and most of these papers give credit for the discovery of CNTs to Sumio Iijima of NEC Corporation, Japan, who, in 1991, published a ground-breaking paper in Nature reporting the discovery of multi-walled carbon nanotubes (MWCNTs)2. This paper has been cited over 27,105 times in the literature (as on January 12, 2016, based on Scopus database). This discovery by Iijima has triggered an avalanche of scientific publications and catapulted CNTs onto the global scientific stage.

Nisha and Mahajan then prepare to take us back in time,

In a guest editorial for the journal Carbon, Marc Monthioux and Vladimir L. Kuznetsov3 have tried to clear the air by describing the chronological events that led to the discovery of carbon nanotubes. As one delves deeper into the history of carbon nanotubes, it becomes more apparent that the origin of CNTs could be even pre-historic in nature.

Recently, Ponomarchuk et al from Russia have reported the presence micro and nano carbon tubes in igneous rocks formed about 250 million years ago4-7. They suggested the possibility of formation of carbon nanotubes during the magmatic processes. It is presumed that the migration of hydrocarbon fluids through the residual melt of the rock groundmass created gas-saturated areas (mostly CH4, CO2, CO) in which condensation and decomposition of hydrocarbon in presence of metal elements resulted in the formation of micro and sub-micron carbon tubes.

Another most compelling evidence of pre-historic naturally occurring carbon nanotubes (MWCNTs) is based on the TEM studies carried out by Esquivel and Murr8 that analyzed 10,000-year-old Greenland ice core samples and it was suggested that probably they could have been formed during combustion of natural gas/methane during natural processes.

However, the validity of this evidence is questionable owing to the lack of clear high-resolution TEM images, high-quality diffraction patterns or Raman spectroscopy data. In addition, [an]other interesting possibility is that the carbon nanotubes could have been directly formed by the transformation of naturally occurring C60 fullerenes in nature without the assistance of man, given the right conditions prevail. Suchanek et al.,9 have actually demonstrated this thesis, under the laboratory environment, by transforming C60 fullerenes into CNTs under hydrothermal conditions.

There is a large body of evidence in literature about the existence of naturally occurring fullerenes in nature, e.g., coal, carboneous rocks, interstellar media, etc. Since the above experiments were conducted under the simulated geological environment, their results imply that CNTs may form in natural hydrothermal environment.

This hypothesis was further corroborated by Velasco-Santos and co-workers10, when they reported the presence of CNTs in a coal–petroleum mix obtained from an actual oil well, identified by the PEMEX (the Mexican Petroleum Company) as P1, which is located in Mexico’s southeast shore. TEM studies revealed that the coal-petroleum mix contained predominantly end-capped CNTs that are nearly 2 µm long with outer diameter varying between few to several tenths of nanometers.

There’s another study supporting the notion that carbon nanotubes may be formed naturally,

In yet another study, researchers from Germany11 have synthesized carbon nanotubes using igneous rock from Mount Etna lava as both support and catalyst. The naturally occurring iron oxide particles present in Etna lava rock make it an ideal material for growing and immobilizing nanocarbons.

When a mixture of ethylene and hydrogen were passed over the pulverized rocks reduced in a hydrogen atmosphere at 700°C, the iron particles catalyzed the decomposition of ethylene to elemental carbon, which gets deposited on the lava rock in the form of tiny tubes and fibers.
This study showed that if a carbon source is available, CNTs/CNFs can grow on a mineral at moderate temperatures, which directs towards the possibilities of carbon nanotube formation in active suboceanic volcanos or even in interstellar space where methane, atomic hydrogen, carbon oxides, and metallic iron are present.

This fascinating and informative piece was originally published in the January 2016 edition of Nanotech Insights (CKMNT newsletter; scroll down) and can be found there although it may be more easily accessible as the June 3, 2016 Nanowerk Spotlight article where it extends over five (Nanowerk) pages and has a number of embedded images along with an extensive list of references at the end.

Enjoy!

Combining chitosan, agarose, and protein gelatine with clay nanotubes to create scaffolds for tissue engineering

Russian scientists have published work on clay nanotube-bipolymer composite scaffolds according to an April 29, 2016 news item on ScienceDaily,

Scientists combined three biopolymers, chitosan and agarose (polysaccharides), and a protein gelatine, as the materials to produce tissue engineering scaffolds and demonstrated the enhancement of mechanical strength (doubled pick load), higher water uptake and thermal properties in chitosan-gelatine-agarose hydrogels doped with halloysite [a clay mineral and a naturally occurring nanotube].

An April 29, 2016 Kazan Federal University (Russia) press release on EurekAlert, which originated the news item, provides more detail and context,

The fabrication of a prototype tissue having functional properties close to the natural ones is crucial for effective transplantation. Tissue engineering scaffolds are typically used as supports which allow cells to form tissue-like structures essentially required for the correct functioning of the cells under the conditions close to the three-dimensional tissue.

Chitosan, a natural biodegradable and chemically versatile biopolymer, has been effectively used in antibacterial, antifungal, anti-tumour and immunostimulating formulations. To overcome the disadvantages of pure chitosan scaffolds such as mechanical fragility and low biological resistance, chitosan scaffolds are typically doped with other supporting compounds which allow for mechanical strengthening, thus yielding ?omposite biologically resistant scaffolds.

Agarose is a galactose-based backbone polysaccharide isolated from red algae, having remarkable mechanical properties which are useful in the design of tissue engineering scaffolds.

Gelatine is formed from collagen by hydrolysis (breaking the triple-helix structure into single-strand molecules) and has a number of advantages over its precursor. It is less immunogenic compared with collagen and it retains informational signal sequences promoting cell adhesion, migration, differentiation and proliferation.

The surface irregularities of the scaffold pores due to the insoluble nanosized components promote the best adhesion of the cells on scaffold materials, while the nanoparticle fillers increase the composites’ strength. Thus, researchers doped halloysite nanotubes into a chitosan-agarose-gelatine matrix to design the implantable 3D cell scaffolds.

The resulting scaffolds demonstrate the shape memory upon deformation and have the porous structure suitable for cell adhesion and proliferation which is essential for artificial tissue fabrication. Macroscopic observations have confirmed that all the samples of scaffolds exhibited the sponge-like behaviour with the shape memory and shape reconstitution after deformation both in wet and dry states.

The swelling experiments indicated that the addition of halloysite can greatly improve the hydrophilicity and wetting of composite scaffolds. The incorporation of halloysite nanotubes into the scaffolds increases the water uptake and subsequently improves the biocompatibility. The intrinsic properties of halloysite nanotubes can be used for further improving the biocompatibility of scaffolds by the loading and sustained release of different bioactive compounds. This opens the prospect for fabrication of scaffolds with defined properties for directed differentiation of cells on matrixes due to gradual release of differentiation factors.

Experiments on two types of human cancer cells (A549 and Hep3B) show that in vitro cell adhesion and proliferation on the nanocomposites occur without changes in viability and cytoskeleton formation.

Further in vivo biocompatibility and biodegradability evaluation in rats has confirmed that the scaffolds promote the formation of novel blood vessels around the implantation sites. The scaffolds show excellent resorption within six weeks after implantation in rats. Neo-vascularization observed in newly formed connective tissue placed near the scaffold allows for the complete restoration of blood flow.

The results obtained indicate that the halloysite doped scaffolds are biocompatible as demonstrated both in vitro and in vivo. In addition, they confirm the great potential of chitosan-agarose-gelatine nanocomposite porous scaffolds doped with halloysite in tissue engineering with potential for sustained nanotube drug delivery.

For anyone interested about drug delivery and nanoparticles, there’s some interesting research profiled in my April 27, 2016 posting which describes how very few nanoparticles are actually delivered to specific sites.

Getting back to the regular program, here’s a link to and a citation for the paper on scaffolds and clay nanotubes,

Clay nanotube–biopolymer composite scaffolds for tissue engineering by Ekaterina A. Naumenko, Ivan D. Guryanov, Raghuvara Yendluri, Yuri M. Lvova, and Rawil F. Fakhrullin. Nanoscale, 2016,8, 7257-7271 DOI: 10.1039/C6NR00641H First published online 01 Mar 2016

This paper is behind a paywall.

Greece and Russia agree to cooperate on quantum and nanotechnology research

I don’t often get a chance to feature Greece here but an April 4, 2016 news item on tornos news (and also on ANAmpa: Athens News Agency [and] Macedonian Press Agency) provides an opportunity,

Greece’s Alternate Minister for Research and Innovation Costas Fotakis and Russian Federation Deputy Minister for Education and Science Ludmila Ogorodova on Friday [April 1, 2016] signed an agreement for cooperation between the two countries in specialist new technologies, such as quantum technology, nanotechnology and related areas.

According to an announcement, the agreement covers four innovative applications in quantum nano-electronics, nanophotonics, quantum information-communication and metamaterials. It extends an invitation to research and technology centres, universities and even public and private research companies to submit proposals in the area of quantum technologies by the end of next June. It envisages financing of up to one million euros in each of the four proposed areas, for programmes to be implemented over 24-36 months.

In spite of the difficult conditions created by the economic crisis, Greece has research centres that have achieved international acclaim and excellence in the emerging field of quantum technology,

So it seems Greece is supplying the quantum expertise and Russia the nanotechnology expertise. It’s a bit surprising that Anatoly Chubais isn’t mentioned since every reference that I’ve ever seen to Russian nanotechnology includes his name as the head of Russia’s state-funded RUSNANO (Russian Nanotechnology Corporation).

Plastic memristors for neural networks

There is a very nice explanation of memristors and computing systems from the Moscow Institute of Physics and Technology (MIPT). First their announcement, from a Jan. 27, 2016 news item on ScienceDaily,

A group of scientists has created a neural network based on polymeric memristors — devices that can potentially be used to build fundamentally new computers. These developments will primarily help in creating technologies for machine vision, hearing, and other machine sensory systems, and also for intelligent control systems in various fields of applications, including autonomous robots.

The authors of the new study focused on a promising area in the field of memristive neural networks – polymer-based memristors – and discovered that creating even the simplest perceptron is not that easy. In fact, it is so difficult that up until the publication of their paper in the journal Organic Electronics, there were no reports of any successful experiments (using organic materials). The experiments conducted at the Nano-, Bio-, Information and Cognitive Sciences and Technologies (NBIC) centre at the Kurchatov Institute by a joint team of Russian and Italian scientists demonstrated that it is possible to create very simple polyaniline-based neural networks. Furthermore, these networks are able to learn and perform specified logical operations.

A Jan. 27, 2016 MIPT press release on EurekAlert, which originated the news item, offers an explanation of memristors and a description of the research,

A memristor is an electric element similar to a conventional resistor. The difference between a memristor and a traditional element is that the electric resistance in a memristor is dependent on the charge passing through it, therefore it constantly changes its properties under the influence of an external signal: a memristor has a memory and at the same time is also able to change data encoded by its resistance state! In this sense, a memristor is similar to a synapse – a connection between two neurons in the brain that is able, with a high level of plasticity, to modify the efficiency of signal transmission between neurons under the influence of the transmission itself. A memristor enables scientists to build a “true” neural network, and the physical properties of memristors mean that at the very minimum they can be made as small as conventional chips.

Some estimates indicate that the size of a memristor can be reduced up to ten nanometers, and the technologies used in the manufacture of the experimental prototypes could, in theory, be scaled up to the level of mass production. However, as this is “in theory”, it does not mean that chips of a fundamentally new structure with neural networks will be available on the market any time soon, even in the next five years.

The plastic polyaniline was not chosen by chance. Previous studies demonstrated that it can be used to create individual memristors, so the scientists did not have to go through many different materials. Using a polyaniline solution, a glass substrate, and chromium electrodes, they created a prototype with dimensions that, at present, are much larger than those typically used in conventional microelectronics: the strip of the structure was approximately one millimeter wide (they decided to avoid miniaturization for the moment). All of the memristors were tested for their electrical characteristics: it was found that the current-voltage characteristic of the devices is in fact non-linear, which is in line with expectations. The memristors were then connected to a single neuromorphic network.

A current-voltage characteristic (or IV curve) is a graph where the horizontal axis represents voltage and the vertical axis the current. In conventional resistance, the IV curve is a straight line; in strict accordance with Ohm’s Law, current is proportional to voltage. For a memristor, however, it is not just the voltage that is important, but the change in voltage: if you begin to gradually increase the voltage supplied to the memristor, it will increase the current passing through it not in a linear fashion, but with a sharp bend in the graph and at a certain point its resistance will fall sharply.

Then if you begin to reduce the voltage, the memristor will remain in its conducting state for some time, after which it will change its properties rather sharply again to decrease its conductivity. Experimental samples with a voltage increase of 0.5V hardly allowed any current to pass through (around a few tenths of a microamp), but when the voltage was reduced by the same amount, the ammeter registered a figure of 5 microamps. Microamps are of course very small units, but in this case it is the contrast that is most significant: 0.1 μA to 5 μA is a difference of fifty times! This is more than enough to make a clear distinction between the two signals.

After checking the basic properties of individual memristors, the physicists conducted experiments to train the neural network. The training (it is a generally accepted term and is therefore written without inverted commas) involves applying electric pulses at random to the inputs of a perceptron. If a certain combination of electric pulses is applied to the inputs of a perceptron (e.g. a logic one and a logic zero at two inputs) and the perceptron gives the wrong answer, a special correcting pulse is applied to it, and after a certain number of repetitions all the internal parameters of the device (namely memristive resistance) reconfigure themselves, i.e. they are “trained” to give the correct answer.

The scientists demonstrated that after about a dozen attempts their new memristive network is capable of performing NAND logical operations, and then it is also able to learn to perform NOR operations. Since it is an operator or a conventional computer that is used to check for the correct answer, this method is called the supervised learning method.

Needless to say, an elementary perceptron of macroscopic dimensions with a characteristic reaction time of tenths or hundredths of a second is not an element that is ready for commercial production. However, as the researchers themselves note, their creation was made using inexpensive materials, and the reaction time will decrease as the size decreases: the first prototype was intentionally enlarged to make the work easier; it is physically possible to manufacture more compact chips. In addition, polyaniline can be used in attempts to make a three-dimensional structure by placing the memristors on top of one another in a multi-tiered structure (e.g. in the form of random intersections of thin polymer fibers), whereas modern silicon microelectronic systems, due to a number of technological limitations, are two-dimensional. The transition to the third dimension would potentially offer many new opportunities.

The press release goes to explain what the researchers mean when they mention a fundamentally different computer,

The common classification of computers is based either on their casing (desktop/laptop/tablet), or on the type of operating system used (Windows/MacOS/Linux). However, this is only a very simple classification from a user perspective, whereas specialists normally use an entirely different approach – an approach that is based on the principle of organizing computer operations. The computers that we are used to, whether they be tablets, desktop computers, or even on-board computers on spacecraft, are all devices with von Neumann architecture; without going into too much detail, they are devices based on independent processors, random access memory (RAM), and read only memory (ROM).

The memory stores the code of a program that is to be executed. A program is a set of instructions that command certain operations to be performed with data. Data are also stored in the memory* and are retrieved from it (and also written to it) in accordance with the program; the program’s instructions are performed by the processor. There may be several processors, they can work in parallel, data can be stored in a variety of ways – but there is always a fundamental division between the processor and the memory. Even if the computer is integrated into one single chip, it will still have separate elements for processing information and separate units for storing data. At present, all modern microelectronic systems are based on this particular principle and this is partly the reason why most people are not even aware that there may be other types of computer systems – without processors and memory.

*) if physically different elements are used to store data and store a program, the computer is said to be built using Harvard architecture. This method is used in certain microcontrollers, and in small specialized computing devices. The chip that controls the function of a refrigerator, lift, or car engine (in all these cases a “conventional” computer would be redundant) is a microcontroller. However, neither Harvard, nor von Neumann architectures allow the processing and storage of information to be combined into a single element of a computer system.

However, such systems do exist. Furthermore, if you look at the brain itself as a computer system (this is purely hypothetical at the moment: it is not yet known whether the function of the brain is reducible to computations), then you will see that it is not at all built like a computer with von Neumann architecture. Neural networks do not have a specialized computer or separate memory cells. Information is stored and processed in each and every neuron, one element of the computer system, and the human brain has approximately 100 billion of these elements. In addition, almost all of them are able to work in parallel (simultaneously), which is why the brain is able to process information with great efficiency and at such high speed. Artificial neural networks that are currently implemented on von Neumann computers only emulate these processes: emulation, i.e. step by step imitation of functions inevitably leads to a decrease in speed and an increase in energy consumption. In many cases this is not so critical, but in certain cases it can be.

Devices that do not simply imitate the function of neural networks, but are fundamentally the same could be used for a variety of tasks. Most importantly, neural networks are capable of pattern recognition; they are used as a basis for recognising handwritten text for example, or signature verification. When a certain pattern needs to be recognised and classified, such as a sound, an image, or characteristic changes on a graph, neural networks are actively used and it is in these fields where gaining an advantage in terms of speed and energy consumption is critical. In a control system for an autonomous flying robot every milliwatt-hour and every millisecond counts, just in the same way that a real-time system to process data from a collider detector cannot take too long to “think” about highlighting particle tracks that may be of interest to scientists from among a large number of other recorded events.

Bravo to the writer!

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

Hardware elementary perceptron based on polyaniline memristive devices by V.A. Demin. V. V. Erokhin, A.V. Emelyanov, S. Battistoni, G. Baldi, S. Iannotta, P.K. Kashkarov, M.V. Kovalchuk. Organic Electronics Volume 25, October 2015, Pages 16–20 doi:10.1016/j.orgel.2015.06.015

This paper is behind a paywall.

A Russia-China high technology investment fund announced

My Sept. 12, 2014 posting mentioned a proposed joint China-Russia nanotechnology investment fund which has now been realized (and changed somewhat). From a Jan. 19, 2016 news item on sputniknews.com,

Russia’s Rusnano nanotechnology company has established a $500-million joint investment fund with the Chinese Zhongrong International Trust, Rusnano CEO Anatoly Chubais said Tuesday.

The agreement between the companies was signed by Chubais and Zhongrong International Trust Chairman Fang Tao, the statement by Rusnano confirmed.

“Zhongrong is one of the largest financial institutes in the Asia-Pacific region that specializes in private equity and financing of large-scale innovative projects… Our partnership is aimed at the creation of new competitive products with the prospect of their launch both in Russia and China, as well as worldwide,” Chubais said, as quoted by Rusnano’s press center.

A Jan. 19, 2016 RUSNANO press release, which originated the news item, provides more details abut the deal and about RUSNANO (Note: A link has been removed),

At the first stage, the RUSNANO Zhongrong United Investment Fund will have $500 mln of capital under management. The Partners of the Fund, RUSNANO Group and Zhongrong Trust International Co., LTD. (Zhongrong), will provide their equity investments in equal portions and establish a joint management company.

The Fund’s investment focus will be concentrated on projects in the growth stage aimed at application, development, and transfer of high technologies (related to electric power industry (including RES), oil and gas industry, as well as microelectronics and biotechnologies) to Russia. It is envisaged that investments into the projects and project companies will be effected on the territory of Russia (not less than 70 %), China, and other countries.

RUSNANO was founded as an open joint stock company in March 2011, through reorganization of state corporation Russian Corporation of Nanotechnologies. RUSNANO is instrumental in realizing government policies for nanoindustry growth, investing in financially effective high-technology projects that guarantee the development of new manufacturing within the Russian Federation. The company invests in nanotechnology companies directly and through investment funds. Its primary investment focus is in electronics, optoelectronics and telecommunications, healthcare and biotechnology, metallurgy and metalwork, energy, mechanical engineering and instrument making, construction and industrial materials, and chemicals and petrochemicals. The Government of the Russian Federation owns 100 percent of the shares in RUSNANO.

Work to establish nanotechnology infrastructure and carry out educational programs is fulfilled by RUSNANO’s Fund for Infrastructure and Educational Programs, which was also established during the reorganization of the Russian Corporation of Nanotechnologies.

Management of the investment assets of RUSNANO are carried out by a limited liability company established in December 2013, RUSNANO Asset Management. Anatoly Chubais is chairman of its Executive Board.

Presumably, the amount is in US dollars (USD). In 2014 when I first stumbled across an English language media announcement about this fund, China was considering ways to make its own currency (Renmibis) an international standard (mentioned in the Sept. 12, 2014 posting). Of course, China’s recent stock market collapse (a Jan. 18, 2016 CNN news article by Andrew Stevens with
Jessie Jiang and Shen Lu provides more details and insight into the collapse) must have been a setback for those currency plans but it’s interesting to see China has pushed ahead with this investment fund.

Ceramic firefighting foam: better at extinguishing fires and nontoxic

A Dec. 14, 2015 news item on Nanowerk announces a new ceramic firefighting foam developed in Russia,

A team of chemists from ITMO University, in collaboration with research company SOPOT, has developed a novel type of firefighting foam based on inorganic silica nanoparticles. The new foam beats existing analogues in fire extinguishing capacity, thermal and mechanical stability and biocompatibility.

A Dec. 14, 2015 ITMO University press release on EurekAlert, which originated the news item, provides more details,

Fighting large-scale fires usually involves firefighting foams based on synthetic substances, such as prefluorinated surfactants, that, despite their effectiveness, are extremely toxic for living organisms. Complete biodegradation of such foams can last for more than 200 years [emphasis mine], with residues quickly penetrating deep into soil and surface water. This leads to the the accumulation of toxic elements in living organisms, such as plants, animals and men. Many countries have declined the use of such fire extinguishing agents or opted for reducing the production of such substances despite the absence of any decent alternatives.

A group of scientists from the International Laboratory of Advanced Materials and Technologies (SCAMT) at ITMO University in Saint Petersburg and research company SOPOT devised a foam, which was awarded full biodegradability and whose fire extinguishing capacity is higher than that of any existing analogue currently in use by fire fighters. After the fire is extinguished, the substance actively absorbs water, softens and falls apart into bioinert silica particles. And even when the foam accidentally enters living organisms, it does not not pose any danger to them.

“Our foam is based on silica nanoparticles, which create a polymer network when exposed to air,” says Alexander Vinogradov, deputy head of the SCAMT laboratory. “Such a network embraces and adheres to the burning object and momentarily cools it down. At the same time, the foam itself hardens. The inorganic origin of this polymer network allows it to resist temperatures above 1000 degrees Celsius, which ensures gigantic stability from the aggressive environment in the midst of a raging fire.”

“Most existing foams are made of organic materials and quickly deteriorate when temperature approaches 300 degrees Celsius. In our case, the foam creates a hard frame that not only puts out the fire, but also protects the object from re-ignition. With ordinary foams, re-ignition occurs within seconds after flame is applied to the object again.”

The scientists conducted a series of large-scale experiments of the hardening foam, including the imitation of an actual forest fire. The foam was used to create a flame retardant belt that was supposed stop the spread of the fire. The tests demonstrated that the foam easily localizes the forest fire seat and can stay active during the whole fire season.

“The flame retardant belt made of our foam will prevent the spread of any forest fire, regardless of its strength and level of complexity,” says Gennady Kuprin, head of SOPOT. “We can localize the fire and be sure that the adjacent territories will be safe. This is crucial to organize evacuation works during forest fires, where 9 of 10 people die in our and other countries.”

The standard firefighting foam can take up to 200 years before completely degrading? I hope this new foam is all they say it is and that they can get it to market. In the meantime, here’s a link to and a citation for the researchers’ paper,

Silica foams for fire prevention and firefighting by Alexander V. Vinogradov, Denis Kuprin, Iosif Abduragimov, Gennadii Kuprin, Evgeniy Serebriyakov, and Vladimir V. Vinogradov. ACS Appl. Mater. Interfaces, DOI: 10.1021/acsami.5b08653
Publication Date (Web): October 22, 2015

Copyright © 2015 American Chemical Society

This is paper is behind a paywall. But, the researchers have made an image of the foam available,

Caption: This is an electronic microscope image of hybrid silica foam. Credit: ITMO University

Caption: This is an electronic microscope image of hybrid silica foam. Credit: ITMO University

For anyone curious about SOPOT, here’s more from the company’s About page,

  “NPO Sopot” was founded in 1994 in St. Petersburg. Its creation was preceded by many years of scientific research and experimental design work done in person at the head of the firm basis of the Ministry of Defence and the Ministry of Internal Affairs of Russia, as well as, with the participation and cooperation with representatives of several institutions of the defense industry (the Sukhoi Design Bureau, Institute TRANSMASH, Academy. Zhukovsky etc.), the Ministry of Civil aviation, Fire Prevention Russian Interior Ministry, the Russian Interior Ministry VIPTSH

General Director of JSC “NPO” Sopot “Gennady Kuprin. Winner of the National Industry Award” Bison-2006 “, the grand prize Emergencies Ministry in 2005 and 2006., Awarded the” Golden Shield of the Russian economy, “international diploma” European quality “member of the International Academy of Patronage, the World Academy of Integrated Security.