China Science & Technology Forum

[JSCh]

Battery scientists develop new strategy for carbon fixation
Source: Xinhua| 2017-08-10 02:07:24|Editor: Mu Xuequan



WASHINGTON, Aug. 9 (Xinhua) -- Scientists in Japan and China said Wednesday they have discovered an "unexpected" approach to capture and store carbon dioxide away from the atmosphere while working toward the elusive lithium-air battery.

In a study published in Joule, a new interdisciplinary energy journal from Cell Press, the researchers reported a new strategy to isolate solid carbon dust from gaseous carbon dioxide (CO2) by using a designing intended for a lithium-CO2 battery.

Converting carbon dioxide emissions into other carbon-containing compounds is desirable due to carbon dioxide's contribution to the greenhouse effect and global warming.

Examples range from natural processes, such as plants turning CO2 into oxygen and sugars, to man-made ones, such as injecting carbon dioxide into rock formations to be trapped as carbonate minerals.

"The problem with most physical and chemical pathways for CO2 fixation is that their products are gases and liquids that need to be further liquefied or compressed, and that inevitably leads to additional energy consumption and even more CO2 emissions," senior author Haoshen Zhou of Japan's National Institute of Advanced Industrial Science and Technology and China's Nanjing University, said in a statement.

"Instead, we are demonstrating an electrochemical strategy for CO2 fixation that yields solid carbon products, as well as a lithium-CO2 battery that can provide the energy necessary for that process."

The researchers worked out the carbon fixation strategy when they tried to recharge a lithium-CO2 battery prototype.

For a reversible Li-CO2 battery, the lithium carbonate and carbon produced during discharge will be fully oxidized to lithium ions and CO2 during recharge.

However, the new study found the so-called oxidation process is irreversible as the lithium carbonate is decomposed while the carbon obtained remains fixed.

In addition, the researchers found that incorporating a tiny amount of ruthenium metal into their design as a catalyst can help avoid extensive carbon deposition and induce better reversibility, converting their carbon-fixing apparatus into a functioning Li-CO2 battery.

The fixation technique might also be adapted to scrub other harmful or polluting gases such as carbon monoxide, sulfur dioxide, nitric oxide, and nitrogen dioxide from the atmosphere, Zhou said.

Looking ahead, the researchers are also excited by their system's potential to perhaps lead to a pathway for converting carbon dioxide into pure carbon and oxygen gas.

"Attaining the release of oxygen gas upon charging, coupled with the accumulation of solid carbon, would realize an electrochemical carbon dioxide fixation strategy analogous to photosynthesis," said Zhou.

This is a flowchart of energy storage and carbon fixation using Li-CO2 technology.
Credit: Qiao et al.

​

Yu Qiao, Shichao Wu, Yang Liu, Sixie Yang, Ping He, Haoshen Zhou. Li-CO2 Electrochemistry: A New Strategy for CO2 Fixation and Energy Storage. Joule, 2017 DOI: 10.1016/j.joule.2017.07.001

 

[JSCh]

China's satellite sends unbreakable cipher from space
Source: Xinhua| 2017-08-10 01:06:38|Editor: Mu Xuequan



BEIJING, Aug. 10 (Xinhua) -- Chinese scientists have become the first to realize quantum key distribution from a satellite to the ground, laying the foundation for building a hack-proof global quantum communication network.

The achievement based on experiments conducted with the world's first quantum satellite, Quantum Experiments at Space Scale (QUESS), was published in the authoritative academic journal Nature on Thursday.

The Nature reviewers commented that the experiment was an impressive achievement, and constituted a milestone in the field.

Nicknamed "Micius" after a 5th century B.C. Chinese philosopher and scientist who is credited as the first person ever to conduct optical experiments, the 600-kilogram-plus satellite was sent into a sun-synchronous orbit at an altitude of 500 km on Aug. 16, 2016.

Pan Jianwei, lead scientist of QUESS and an academician of the Chinese Academy of Sciences (CAS), said the satellite sent quantum keys to ground stations in Xinglong, in north China's Hebei Province, and Nanshan near Urumqi, capital of northwest China's Xinjiang Uygur Autonomous Region.

Communication distance between the satellite and the ground stations varied from 645 km to 1,200 km, and the quantum key transmission rate from satellite to ground is up to 20 orders of magnitude more efficient than that expected using an optical fiber of the same length, said Pan.

When the satellite flies over China, it provides an experiment window of about 10 minutes. During that time, 300 kbit secure keys can be generated and sent by the satellite, according to Pan.

"That, for instance, can meet the demand of making an absolute safe phone call or transmitting a large amount of bank data," Pan said.

"Satellite-based quantum key distribution can be linked to metropolitan quantum networks where fibers are sufficient and convenient to connect numerous users within a city over 100 km. We can thus envision a space-ground integrated quantum network, enabling quantum cryptography - most likely the first commercial application of quantum information - useful at a global scale," Pan said.

The establishment of a reliable and efficient space-to-ground link for faithful quantum state transmission paves the way to global-scale quantum networks, he added.

HACK-PROOF COMMUNICATION

Private and secure communications are highly sought after. Traditional public key cryptography usually relies on the perceived computational intractability of certain mathematical functions.

But a powerful quantum computer, which scientists around the world are still developing, is viewed as a threat in that it could make everything on a conventional computer hackable.

However, like a coin with two sides, quantum mechanics also serves as protector of information.

By harnessing quantum entanglement, the quantum key technology is used in quantum communications, ruling out the possibility of wiretapping and perfectly securing the communication.

Pan explained that a quantum key is formed by a string of random numbers generated between two communicating users to encode information. Once intercepted or measured, the quantum state of the key will change, and the information being intercepted will self-destruct.

An eavesdropper on the quantum channel attempting to gain information on the key will inevitably introduce disturbance to the system, and can be detected by the communicating users, said Pan.

BREAKING LIMITS IN SPACE

In practice, the achievable distance for quantum key distribution has been limited to a few hundred kilometers, due to the loss of photons in transmission through optical fibers, Pan said.

"If we transmit the quantum key through a 1,200-km fiber, even with a perfect single-photon source and ideal single-photon detectors, we would obtain only a 1-bit sifted key over six million years," Pan said.

A more direct and promising solution for global-scale quantum key distribution is through satellites. Transmitting photons between the satellite and ground stations greatly broadens the reach of quantum communication, Pan said.

Compared with terrestrial channels, the satellite-to-ground connection has significantly reduced losses. This is mainly because the effective thickness of the atmosphere is 10 km, and most of the photon's transmission path is in empty space with negligible absorption and turbulence.

Scientists expect quantum communications to fundamentally change human development in the next two or three decades, as there are enormous prospects for applying the new generation of communication in fields like defense, military and finance.

CHINA'S QUANTUM LEAP

In the same issue of Nature, another experiment, the ground-to-satellite quantum teleportation, conducted via Micius, was also published. In June, the same team's experiment in distribution of entangled photon pairs over 1,200 kilometers was published as a cover article in the academic journal Science.

Chinese scientists have completed all the experiments designed for Micius a year ahead of schedule.

Karl Ziemelis, chief physical sciences editor at Nature, said that with the publication of these new papers, Pan and his colleagues have completed their demonstration of a trio of quantum experiments that will be central to any global space-based quantum Internet.

"I mean you could say that the sky's the limit for quantum technologies, but that is a little bit conservative actually. They've gone beyond the sky with these latest experiments. And it's a testament to China's investments and significant efforts in the physical sciences that this group has been able to push research in practical quantum communication technologies to such an astronomical height," said Ziemelis.

CAS president Bai Chunli said the achievements show China has reached a leading position in the field of quantum communication research.

"Micius has ushered in the construction of global quantum communication, the study of space quantum physics and experimental verification of quantum gravity theories. It helps China's race to control the command point of quantum science and technology, and enables China to become a leader in the field," Bai said.

In addition to Micius, China has launched a series of space science satellites, including the Dark Matter Particle Explorer, the recoverable satellite SJ-10, and the Hard X-ray Modulation Telescope, over the past two years.

Bai said China plans to launch more space science satellites in the next five to 10 years, focusing on the frontiers of science, such as the study of the origin of the universe, black holes, gravitational waves, exoplanets, resources exploration of the solar system and solar storms.

The implementation of these projects is expected to bring more scientific breakthroughs, and help China to become a powerful nation in the field of science and technology, Bai said.

#####​

• Sheng-Kai Liao, Wen-Qi Cai, Wei-Yue Liu, Liang Zhang, Yang Li, Ji-Gang Ren, Juan Yin, Qi Shen, Yuan Cao, Zheng-Ping Li, Feng-Zhi Li, Xia-Wei Chen, Li-Hua Sun, Jian-Jun Jia, Jin-Cai Wu, Xiao-Jun Jiang, Jian-Feng Wang, Yong-Mei Huang, Qiang Wang, Yi-Lin Zhou, Lei Deng, Tao Xi, Lu Ma, Tai Hu, Qiang Zhang, Yu-Ao Chen, Nai-Le Liu, Xiang-Bin Wang, Zhen-Cai Zhu, Chao-Yang Lu, Rong Shu, Cheng-Zhi Peng, Jian-Yu Wang & Jian-Wei Pan. Satellite-to-ground quantum key distribution. Nature (2017). DOI: 10.1038/nature23655
• Ji-Gang Ren, Ping Xu, Hai-Lin Yong, Liang Zhang, Sheng-Kai Liao, Juan Yin, Wei-Yue Liu, Wen-Qi Cai, Meng Yang, Li Li, Kui-Xing Yang, Xuan Han, Yong-Qiang Yao, Ji Li, Hai-Yan Wu, Song Wan, Lei Liu, Ding-Quan Liu, Yao-Wu Kuang, Zhi-Ping He, Peng Shang, Cheng Guo, Ru-Hua Zheng, Kai Tian, Zhen-Cai Zhu, Nai-Le Liu, Chao-Yang Lu, Rong Shu, Yu-Ao Chen, Cheng-Zhi Peng, Jian-Yu Wang & Jian-Wei Pan. Ground-to-satellite quantum teleportation. Nature (2017). DOI: 10.1038/nature23675

实现星地高速量子密钥分发
Satellite to ground quantum key distribution.

完成地星量子隐形传态实验
Ground to satellite quantum teleportation.

 

[JSCh]

Jurassic's earliest gliding mammals undermine dinosaurs’ reign
Two exquisitely preserved fossils, dated to 160 million years ago, indicate dinosaurs did not dominate the Mesozoic Era as believed.

The Maiopatagium furculiferum fossil.
Zhe-Xi Luo / University of Chicago

The earliest examples of gliding mammals yet discovered, dated to the Jurassic period about 160 million years ago, suggest dinosaurs did not dominate the prehistoric Earth as much as has been believed.

As the first winged mammals, the identified fossils of two gliders demonstrate the wide ecological diversity attained by early mammals, says Zhe-Xi Luo, professor of organismal biology and anatomy at the University of Chicago, who is co-author of two new papers analysing the animals, published in Nature. This degree of early evolutionary diversity, he suggests, “means dinosaurs likely did not dominate the Mesozoic landscape as much as previously thought”.

Bearing some similarities in appearance to modern gliding mammals such as flying squirrels and possums, the “exquisitely fossilised” remains of the two animals unearthed from China’s renowned Tiaojishan Formation show wing-like skin membranes between long fore and hind limbs, and skeletal features in their shoulder joints and forelimbs that would make them capable gliders. Their long fingers (or toes) are suited to gripping branches, indicating trees were their natural habitat, while their teeth indicate they ate a mainly herbivorous diet.

Their capacity for aerial travel – what is known as ‘volant locomotion’ – evolved roughly 100 million before the earliest known gliding members of the family known as therians, to which squirrel and possum flyers and gliders belong. “These Jurassic mammals are truly ‘the first in glide’,” Luo says. “In a way, they got the first wings among all mammals.”

Luo and his colleagues from the University of Chicago, the Beijing Museum of Natural History and Hebei GEO University categorise the two gliders as belonging to the haramiyidan clade, an extinct branch of the mammalian evolutionary tree considered a forerunner of modern mammals. The clade extends back to the Late Triassic (201-252 million years ago).

An artist’s impression of Maiopatagium in a Jurassic forest.
April I. Neander / University of Chicago

For this reason the scientists consider the two newly discovered gliders as more antiquated than Volaticotherium antiquus, a squirrel-sized gliding mammal dug up in Inner Mongolia and presented to the world in 2006. It has been dated as being about the same age of the new fossils.

V. antiquus, however, belonged to the eutriconodont clade, which extends back only to about 170 million years ago and is technically part of the modern mammal family. “Eutriconodonts are rooted between modern monotremes and modern marsupials-placentals on the mammal evolutionary tree,” Luo explains. “Volaticotherium’s gliding evolved after the split of monotremes on one hand and marsupial-placental mammals on the other.”

So while in absolute geological terms all three fossils are about the same age, Luo says, the two new gliders evolved at an earlier point in mammalian evolution, prior to the diversification of modern mammals into monotremes, marsupials and placentals. “The evolutionary antiquity is much older for the newly found Maiopatagium and Vilevolodon than for Volaticotherium. That’s why we say they are the first winged mammals.”

One of the gliders, Maiopatagium furculiferum, was dug up from the Daxishan fossil site in Jianchang County, Liaoning Province. The other, Vilevolodon diplomylos, was unearthed at the Nanshimen fossil site in Qinglong County, Hebei Province.

Their evolution to glide between trees to forage for food demonstrates the the adaptability of early mammaliaformes to exploit new ecological niches otherwise inaccessible to competitors, Luo and his co-authors say. “Evolution of gliding behaviour is an important evolutionary transition between divergent land-based and aerial habitats,” they write in the paper analysing Maiopatagium furculiferum.

A map showing the sites where the glider fossils were found.
Zhe-Xi Luo / University of Chicago

Together with many other fossils described by Luo and colleagues over the past decade or so, the new fossils provide strong evidence that mammals adapted well and were more ubiquitous in an age once presumed to have been the domain of dinosaurs.

“The traditional and historical view was that when dinosaurs dominated the world, mammals were small, generalised and without much functional or ecological diversity,” Luo says. “In simple terms, mammals were not able to diversify when dinosaurs dominated the terrestrial ecosystem. The popular version of this view was that mammals always lived in the shadow of dinosaurs. But that was then.”

A stream of new discoveries in the past 15 years has shown that mammals which co-existed with dinosaurs during the Mesozoic evolved into semi-aquatic forms, such as Castorocauda, subterranean forms, such as Docofossor, and many arboreal forms, such as Agilodocodon and Arboroharamiya.

“Mesozoic mammals essentially evolved all the distinctive ecomorphotypes like those of modern mammals of small-to-mid-sized bodies,” Luo says.

Tim Wallace is a contributor to Cosmos Magazine


Jurassic's earliest gliding mammals undermine dinosaurs’ | Cosmos

• Qing-Jin Meng, David M. Grossnickle, Di Liu, Yu-Guang Zhang, April I. Neander, Qiang Ji & Zhe-Xi Luo. New gliding mammaliaforms from the Jurassic, Nature (2017). DOI: 10.1038/nature23476
• Zhe-Xi Luo, Qing-Jin Meng, David M. Grossnickle, Di Liu, April I. Neander, Yu-Guang Zhang & Qiang Ji. New evidence for mammaliaform ear evolution and feeding adaptation in a Jurassic ecosystem, Nature (2017). DOI: 10.1038/nature23483

 

[JSCh]

Transplant innovation a lifesaver
By ZHENG CAIXIONG | China Daily | Updated: 2017-08-11 07:04

A cirrhosis patient in Guangzhou has been discharged from the hospital after receiving a new liver using a groundbreaking technique that is expected to keep healthy organs from going to waste.

The man, identified only as Wang, 51, said on Thursday that he felt well, and expressed his gratitude to the medical staff at the First Affiliated Hospital of Sun Yat-sen University.

The operation on July 23 is the first time in China a transplanted organ was kept alive using new technology that provides uninterrupted blood flow, according to the hospital.

After collection from the donor, the liver was put into a machine developed by Chinese doctors and scientists that pumped body-temperature blood into the hepatic artery, replicating the effect of being in a body, keeping the organ fresh.

Organs usually are stored on ice, but after 30 minutes without the flow of blood, they begin to die. This new technique means an organ can be stored for much longer－in the case of livers, four hours.

"The technology is a breakthrough," said He Xiaoshun, vice-president of the hospital and the top expert in its organ transplant center. The success of Wang's surgery "shows the technology can also be used in other transplant operations, including hearts, kidneys and lungs, as liver transplants are the most difficult".

The method can also "help reduce complications and shorten the period of recovery compared with traditional transplants", he said, adding that Wang was transferred to an ordinary ward from the intensive care unit only 19 hours after surgery.

More than 4,080 transplantation surgeries were carried out in China last year. However, many healthy organs are wasted due to constraints in storage and transportation, experts said.

He's team began experimenting with ways to provide uninterrupted blood flow to organs seven years ago.

After observing Wang's recovery, the hospital carried out the same operation on a 50-year-old man on Aug 8. That patient is now recovering, He said, adding that the third such transplant will take place on Friday.

While the same type of technology is being used and tested in a few other countries, machines that can keep livers alive are on the cutting edge.

Wang Xuehao, an academician at the Chinese Academy of Engineering, said the blood flow machine is a disruptive innovation that showcases the nation's great contribution to organ transplantation.

 

[JSCh]

In breakthrough, scientists eliminate dangerous viruses in live pigs through gene editing
Source: Xinhua | 2017-08-11 05:23:46 | Editor: huaxia

First pigs free of porcine endogenous retroviruses (PERVS) (The image distributed by eGenesis Yang Luhan/Xinhua)

WASHINGTON, Aug. 10 (Xinhua) -- Scientists on Thursday announced a breakthrough in producing the first batch of live pigs free of dangerous viruses, setting the stage for transplanting life-saving organs from the animals into humans.

In a paper published in the U.S. journal Science, researchers from the U.S., China and Denmark described how they used the powerful gene-editing tool CRISPR to modify pig cells and produce embryos free of the so-called porcine endogenous retroviruses (PERVs) in order to create the desired piglets.

Luhan Yang, co-founder and chief scientific officer at a Massachusetts-based biotechnology company called eGenesis, who led the study, hailed the first PERV-free pigs as "an important milestone" for the use of animal organs for human transplant.

"Our work fundamentally addressed the risk of cross-species viral transmission in xenotransplantation," Yang told Xinhua.

Worldwide, human organs for transplant are in short supply. Researchers and clinicians have long hoped that the challenge could be alleviated through the availability of suitable animal organs for transplant, a concept known as xenotransplantation.

Pigs in particular have been especially promising candidates due to their similar size and physiology to humans. But one of the largest safety concerns has been the fact that most mammals including pigs contain repetitive, latent retrovirus fragments in their genomes -- present in all their living cells -- that are harmless to their native hosts but can cause disease in other species.

The presence of PERVs in pigs brought more than a billion dollars'worth of pharmaceutical industry investments in developing xenotransplant methods to a standstill by the early 2000s, according to the study.

Then, Yang and colleagues demonstrated in a 2015 Science paper a method to inactivate all 62 copies of PERVs in porcine cells and eliminated PERV transmission to human cells.

In the new study, the researchers developed a strategy to enable efficient and precise gene editing to deactivate all 25 genomic sites related to PERVs in pig fibroblast cells using the CRISPR technology.

In conjunction with a method to inhibit cell death during gene editing, they successfully produced viable PERV-free porcine embryos via somatic cell nuclear transfer, the same method that created Dolly, the world's first cloned sheep, in 1996.

The team then implanted the PERV-free embryos into surrogate sows and demonstrated the absence of PERV re-infection, initially in fetuses and finally in recently born piglets.

"At least for those who are four months old, we did not observe difference in physiology between the modified piglets and normal ones," Yang said.

"We will continue to use this platform to engineer the pig genome, on the basis of PERV-free pigs, to enhance pig-to-human immunological compatibility for the clinical xenotransplantation of porcine organs as early as possible," she said.

The paper was also authored by researchers from Harvard University and China's Zhejiang University, Yunnan Agricultural University, Third Military Medical University and Research Institute of Shenzhen Jinxinnong Technology Co Ltd as well as Denmark's Aarhus University.

Professor Darren Griffin of the University of Kent, who was not involved in the study, said the finding represents "a significant step forward towards the possibility of making xenotransplantation a reality."

"However, there are so many variables including ethical issues to resolve before xenotransplantation can take place," Griffin cautioned.

Another outside expert, Professor Ian McConnell of the University of Cambridge, sounded a similarly cautionary note, calling this work "a promising first step."

"It remains to be seen whether these results can be translated into a fully safe strategy in organ transplantation," McConnell said. "Even if organs from these gene-edited pigs could be safely used to overcome virus transmission, there remain formidable obstacles in overcoming immunological rejection and physiological incompatibility of pig organs in humans."

Dong Niu, Hong-Jiang Wei, Lin Lin, Haydy George, Tao Wang, I-Hsiu Lee, Hong-Ye Zhao, Yong Wang, Yinan Kan, Ellen Shrock, Emal Lesha, Gang Wang, Yonglun Luo, Yubo Qing, Deling Jiao, Heng Zhao, Xiaoyang Zhou, Shouqi Wang, Hong Wei, Marc Güell, George M. Church, Luhan Yang. Inactivation of porcine endogenous retrovirus in pigs using CRISPR-Cas9. Science (2017). DOI: 10.1126/science.aan4187​

 

[JSCh]

August 9, 2017
Super-light material possesses high strength, other attributes

WEST LAFAYETTE, Ind. — A new featherweight, flame-resistant and super-elastic “metamaterial” has been shown to combine high strength with electrical conductivity and thermal insulation, suggesting potential applications from buildings to aerospace.

The composite combines nanolayers of a ceramic called aluminum oxide with graphene, which is an extremely thin sheet of carbon. Although both the ceramic and graphene are brittle, the new metamaterial has a honeycomb microstructure that provides super-elasticity and structural robustness. Metamaterials are engineered with features, patterns or elements on the scale of nanometers, or billionths of a meter, providing new properties for various potential applications.

Graphene would ordinarily degrade when exposed to high temperature, but the ceramic imparts high heat tolerance and flame-resistance, properties that might be useful as a heat shield for aircraft. The light weight, high-strength and shock-absorbing properties could make the composite a good substrate material for flexible electronic devices and “large strain sensors.” Because it has high electrical conductivity and yet is an excellent thermal insulator, it might be used as a flame-retardant, thermally insulating coating, as well as sensors and devices that convert heat into electricity, said Gary Cheng, an associate professor in the School of Industrial Engineering at Purdue University.

“This material is lighter than a feather,” he said. “The density is really low. It has a very high strength-to-weight ratio.”

Findings were detailed in a research paper published on May 29 in the journal Advanced Materials. The paper was a collaboration between Purdue, Lanzhou University and the Harbin Institute of Technology, both in China, and the U.S. Air Force Research Laboratory. A research highlight about the work appeared in the journal Nature Research Materials and is available at https://www.nature.com/articles/natrevmats201744.pdf. A YouTube video about the work is available.

A new composite material combines ultra-lightweight with flame-resistance, super-elasticity and other attributes that could make it ideal for various applications. Here, the material is viewed with a scanning electron microscope, while its flame resistance is put to the test. (Purdue University photo)

“The outstanding properties of today’s ceramic-based components have been used to enable many multifunctional applications, including thermal protective skins, intelligent sensors, electromagnetic wave absorption and anticorrosion coatings,” Cheng said.

However, ceramic-based materials have several fundamental bottlenecks that prevent their ubiquitous use as functional or structural elements.

“Here, we report a multifunctional ceramic-graphene metamaterial with microstructure-derived super-elasticity and structural robustness,” Cheng said. “We achieved this by designing a hierarchical honeycomb microstructure assembled with multi-nanolayer cellular walls serving as basic elastic units. This metamaterial demonstrates a sequence of multifunctional properties simultaneously that have not been reported for ceramics and ceramics–matrix–composite structures.”

The composite material is made of interconnected cells of graphene sandwiched between ceramic layers. The graphene scaffold, referred to as an aerogel, is chemically bonded with ceramic layers using a process called atomic layer deposition.

“We carefully control the geometry of this graphene aerogel,” he said. “And then we deposit very thin layers of the ceramic. The mechanical property of this aerogel is multifunctional, which is very important. This work has the potential of making graphene a more functional material.”

The process might be scaled up for industrial manufacturing, he said.

Future work will include research to enhance the material’s properties, possibly by changing its crystalline structure, scaling up the process for manufacturing and controlling the microstructure to tune material properties.

The research was funded in part by the National Institute of Standards and Technology.

Writer: Emil Venere, 765-494-4709, venere@purdue.edu


Super-light material possesses high strength, other attributes - Purdue University

Qiangqiang Zhang, Dong Lin, Biwei Deng, Xiang Xu, Qiong Nian, Shengyu Jin, Kevin D. Leedy, Hui Li, Gary J. Cheng. Flyweight, Superelastic, Electrically Conductive, and Flame-Retardant 3D Multi-Nanolayer Graphene/Ceramic Metamaterial. Advanced Materials (2017). DOI: 10.1002/adma.201605506​

 

[JSCh]

Blind quantum computing for everyone
August 11, 2017 by Lisa Zyga

(Phys.org)—For the first time, physicists have demonstrated that clients who possess only classical computers—and no quantum devices—can outsource computing tasks to quantum servers that perform blind quantum computing. "Blind" means the quantum servers do not have full information about the tasks they are computing, which ensures that the clients' computing tasks are kept secure. Until now, all blind quantum computing demonstrations have required that clients have their own quantum devices in order to delegate tasks for blind quantum computing.

The team of physicists, led by Jian-Wei Pan and Chao-Yang Lu at the University of Science and Technology of China, have published a paper on the demonstration of blind quantum computing for classical clients in a recent issue of Physical Review Letters.

"We have demonstrated for the first time that a fully classical client can delegate a quantum computation to untrusted quantum servers while maintaining full privacy," Lu told Phys.org.

The idea behind blind quantum computing is that, while there are certain computing tasks that quantum computers can perform exponentially better than classical computers, quantum computing still involves expensive, complex hardware that will make it inaccessible for most clients. So instead of everyone owning their own quantum computing devices, blind quantum computing makes it possible for clients to outsource their computing tasks to quantum servers that do the job for them. Ensuring that the quantum computing is performed blindly is important, since many of the potential applications of quantum computing will likely require a high degree of security.

Although several blind quantum computing protocols have been performed in the past few years, they have all required that the clients have the ability to perform certain quantum tasks, such as prepare or measure qubit states. Eliminating this requirement will provide greater access to blind quantum computing, since most clients only have classical computing systems.

In the new study, the physicists experimentally demonstrated that a classical client can outsource a simple problem (factoring the number 15) to two quantum servers that do not fully know what problem they are solving. This is because each server completes part of the task, and it is physically impossible for the servers to communicate with each other. To ensure that the quantum servers are performing their tasks honestly, the client can give them "dummy tasks" that are indistinguishable from the real task to test their honesty and correctness.

The researchers expect that the new method can be scaled up for realizing secure, outsourced quantum computing, which could one day be implemented on quantum cloud servers and make the power of quantum computing widely available.

"Blind quantum computing protocol is an important privacy-preserving technique for future secure quantum cloud computing and secure quantum networks," Lu said. "Applying our implemented blind quantum computing protocol, classical clients could delegate computation tasks to servers 'in the cloud' blindly and correctly without directly owning quantum devices. It saves resources and makes scalable quantum computing possible."

In the future, the physicists want to make blind quantum computing even easier for clients by further reducing the requirements.

"We plan to study more robust blind quantum computing protocols with fewer required resources and fewer constraints theoretically and experimentally," Lu said. "We will also explore blind quantum computing for more application scenarios, such as multi-user blind quantum computing, publicly verifiable quantum computing, and secure multi-party quantum computing."


https://phys.org/news/2017-08-quantum.html

He-Liang Huang, Qi Zhao, Xiongfeng Ma, Chang Liu, Zu-En Su, Xi-Lin Wang, Li Li, Nai-Le Liu, Barry C. Sanders, Chao-Yang Lu, and Jian-Wei Pan. Experimental Blind Quantum Computing for a Classical Client. Physical Review Letters (2017). DOI: 10.1103/PhysRevLett.119.050503 , Also at arXiv:1707.00400​

 

[JSCh]

Converting greenhouse gas to value-added syngas takes a big step forward

Zhang Ningning
00:05 UTC+8, 2017-08-14

Ti Gong
The demonstration plant located in Shanxi Province.

The world's largest production plant to produce value-added synthesis gas — known as syngas — has passed an industrial demonstration with flying colors.

Syngas is made from methane and carbon dioxide, two main greenhouse gases.

The successful industrial demonstration expanded the “dry reforming” technology's to an almost commercial scale and paves the way for its future commercialization, said the developer, Shanghai Advanced Research Institute of Chinese Academy of Sciences, on Sunday.

Carbon dioxide and methane are key carbon resources, local researchers said. Converting the greenhouse gases to syngas of carbon monoxide and hydrogen, known as "drying reforming of methane," is receiving increasing attention, the researchers said.

This is not only because the value-added syngas is a key raw material for a wide range of chemical products and fuels, but also because of its "great incentives" in environment protection.

"Compared with traditional steam reforming, the dry reforming almost does not consume water, but uses the greenhouse gases," said Dr Zhang Jun, a leading researcher of the project. "It can converse resources and contribute to ease the increasing pressure on greenhouse emission."

However, two of the biggest challenges to apply the dry reforming at an industrial scale lie in the catalyst that can resist severe carbon deposition and its special reactor.

The bottlenecks restricted the novel technology in in the laboratory. The issues were resolved by the research team of the institute, particularly through the development of a "highly stable nanocomposite catalyst."

“With the development, the technology can be applied on offshore natural gas, shale gas that contains large amount of carbon dioxide, as well as in traditional coal chemical industry,” said Zhang.

The demonstration plant, which is sited in north China’s Shanxi Province, can produce more than 200,000 normal cubic meters of the syngas and convert 60 tons of carbon dioxide daily.

As of Sunday, it had been operating "stably" for more than 1,000 hours. Shanxi is China’s main coal producer.

The technology demonstration project was co-launched by the scientific institute, Shanxi Lu’an Coal Corporation Limited and Shell Global Solutions International. The three parties plan to promote technology’s commercialization worldwide.

 

[Galactic Penguin SST]

Jurassic's earliest gliding mammals undermine dinosaurs’ reign
Two exquisitely preserved fossils, dated to 160 million years ago, indicate dinosaurs did not dominate the Mesozoic Era as believed.

The Maiopatagium furculiferum fossil.
Zhe-Xi Luo / University of Chicago

The earliest examples of gliding mammals yet discovered, dated to the Jurassic period about 160 million years ago, suggest dinosaurs did not dominate the prehistoric Earth as much as has been believed.

As the first winged mammals, the identified fossils of two gliders demonstrate the wide ecological diversity attained by early mammals, says Zhe-Xi Luo, professor of organismal biology and anatomy at the University of Chicago, who is co-author of two new papers analysing the animals, published in Nature. This degree of early evolutionary diversity, he suggests, “means dinosaurs likely did not dominate the Mesozoic landscape as much as previously thought”.

Bearing some similarities in appearance to modern gliding mammals such as flying squirrels and possums, the “exquisitely fossilised” remains of the two animals unearthed from China’s renowned Tiaojishan Formation show wing-like skin membranes between long fore and hind limbs, and skeletal features in their shoulder joints and forelimbs that would make them capable gliders. Their long fingers (or toes) are suited to gripping branches, indicating trees were their natural habitat, while their teeth indicate they ate a mainly herbivorous diet.

Their capacity for aerial travel – what is known as ‘volant locomotion’ – evolved roughly 100 million before the earliest known gliding members of the family known as therians, to which squirrel and possum flyers and gliders belong. “These Jurassic mammals are truly ‘the first in glide’,” Luo says. “In a way, they got the first wings among all mammals.”

Luo and his colleagues from the University of Chicago, the Beijing Museum of Natural History and Hebei GEO University categorise the two gliders as belonging to the haramiyidan clade, an extinct branch of the mammalian evolutionary tree considered a forerunner of modern mammals. The clade extends back to the Late Triassic (201-252 million years ago).

An artist’s impression of Maiopatagium in a Jurassic forest.
April I. Neander / University of Chicago

For this reason the scientists consider the two newly discovered gliders as more antiquated than Volaticotherium antiquus, a squirrel-sized gliding mammal dug up in Inner Mongolia and presented to the world in 2006. It has been dated as being about the same age of the new fossils.

V. antiquus, however, belonged to the eutriconodont clade, which extends back only to about 170 million years ago and is technically part of the modern mammal family. “Eutriconodonts are rooted between modern monotremes and modern marsupials-placentals on the mammal evolutionary tree,” Luo explains. “Volaticotherium’s gliding evolved after the split of monotremes on one hand and marsupial-placental mammals on the other.”

So while in absolute geological terms all three fossils are about the same age, Luo says, the two new gliders evolved at an earlier point in mammalian evolution, prior to the diversification of modern mammals into monotremes, marsupials and placentals. “The evolutionary antiquity is much older for the newly found Maiopatagium and Vilevolodon than for Volaticotherium. That’s why we say they are the first winged mammals.”

One of the gliders, Maiopatagium furculiferum, was dug up from the Daxishan fossil site in Jianchang County, Liaoning Province. The other, Vilevolodon diplomylos, was unearthed at the Nanshimen fossil site in Qinglong County, Hebei Province.

Their evolution to glide between trees to forage for food demonstrates the the adaptability of early mammaliaformes to exploit new ecological niches otherwise inaccessible to competitors, Luo and his co-authors say. “Evolution of gliding behaviour is an important evolutionary transition between divergent land-based and aerial habitats,” they write in the paper analysing Maiopatagium furculiferum.

A map showing the sites where the glider fossils were found.
Zhe-Xi Luo / University of Chicago

Together with many other fossils described by Luo and colleagues over the past decade or so, the new fossils provide strong evidence that mammals adapted well and were more ubiquitous in an age once presumed to have been the domain of dinosaurs.

“The traditional and historical view was that when dinosaurs dominated the world, mammals were small, generalised and without much functional or ecological diversity,” Luo says. “In simple terms, mammals were not able to diversify when dinosaurs dominated the terrestrial ecosystem. The popular version of this view was that mammals always lived in the shadow of dinosaurs. But that was then.”

A stream of new discoveries in the past 15 years has shown that mammals which co-existed with dinosaurs during the Mesozoic evolved into semi-aquatic forms, such as Castorocauda, subterranean forms, such as Docofossor, and many arboreal forms, such as Agilodocodon and Arboroharamiya.

“Mesozoic mammals essentially evolved all the distinctive ecomorphotypes like those of modern mammals of small-to-mid-sized bodies,” Luo says.

Tim Wallace is a contributor to Cosmos Magazine


Jurassic's earliest gliding mammals undermine dinosaurs’ | Cosmos

• Qing-Jin Meng, David M. Grossnickle, Di Liu, Yu-Guang Zhang, April I. Neander, Qiang Ji & Zhe-Xi Luo. New gliding mammaliaforms from the Jurassic, Nature (2017). DOI: 10.1038/nature23476
• Zhe-Xi Luo, Qing-Jin Meng, David M. Grossnickle, Di Liu, April I. Neander, Yu-Guang Zhang & Qiang Ji. New evidence for mammaliaform ear evolution and feeding adaptation in a Jurassic ecosystem, Nature (2017). DOI: 10.1038/nature23483

No wonder the Liaoning Province is today the home of the momonga (「天松鼠」, モモンガ), or Haneul daramjui (하늘다람쥐) as known in North Korea!

Spoiler

http://livedoor.blogimg.jp/karapaia_zaeega/imgs/f/8/f8501811.jpg
http://karapaia.com/archives/52077027.html

▲ きゅんきゅんするモモンガたちを集めた厳選モモンがぞう（動画あり）
Parked

Spoiler

http://livedoor.blogimg.jp/karapaia_zaeega/imgs/f/6/f666f89b.jpghttp://
http://karapaia.com/archives/52077027.html

▲ きゅんきゅんするモモンガたちを集めた厳選モモンがぞう（動画あり）
Taxiing

Spoiler

https://ncache.ilbe.com/files/attac...28926461/f5ffa8f2cf368657638032c3fa3c6fb0.jpg
http://www.ilbe.com/7428926461
https://rr.img.naver.jp/mig?src=htt...dth=1000&theight=0&qlt=80&res_format=jpg&op=r
https://matome.naver.jp/odai/2142875184074585401/2142875211274976503

▲ エゾモモンガ (2015/09/01) の記事画像
Taxiing

Spoiler

http://cfile21.uf.tistory.com/image/2630973E571376E919573D
http://leehg0413.tistory.com/entry/하늘-다람쥐-1

▲
하늘 다람쥐 2016.04.17 20:44
Takeoff

Spoiler

http://cfile4.uf.tistory.com/image/2736BD3E571376EA1289A8
http://leehg0413.tistory.com/entry/하늘-다람쥐-1

▲
하늘 다람쥐 2016.04.17 20:44
Takeoff

Spoiler

https://www.tougewo-koete.jp/animal/momonga/2/yamisora.jpg
http://www.tougewo-koete.jp/animal/momonga/momonga02.html

▲ モモンガの特徴でもある移動手段が滑空です。通常は20～30mの飛行距離ですが時折、50m以上もあるところから滑空してくることもあります。音も無く飛んできますがモモンガの目は、真剣です
Front cam view

Spoiler

https://photo1.ganref.jp/photo/0/beda518d6fa4c7dd81be3ac8cc8f408c/original.jpg
http://ganref.jp/m/toyose/portfolios/photo_detail/beda518d6fa4c7dd81be3ac8cc8f408c

▲ エゾモモンガの飛行シーン
Front cam view

Spoiler

https://pds.exblog.jp/pds/1/201508/17/19/a0145819_2122293.jpg
http://yah55.exblog.jp/21557227/

▲ フライング・モモ
Side cam view

Spoiler

https://pds.exblog.jp/pds/1/201508/01/15/b0189415_20195788.jpg
http://troutinn.exblog.jp/24748009/

▲ モモンガ滑空 (2015/08/01) の記事画像
Ground cam view

Spoiler

https://pds.exblog.jp/pds/1/201509/01/15/b0189415_1991587.jpg
http://troutinn.exblog.jp/24846530/

▲ エゾモモンガ (2015/09/01) の記事画像
Rear cam view


Video published 2015.04.15

Sky squirrel gliding while carrying baby in the mouth ... First captured on camera

http://player.sbs.co.kr/SBSPlayer.swf?ver=1863
http://news.sbs.co.kr/news/endPage.do?news_id=N1002929847

 

[JSCh]

China launches brain-imaging factory
Hub aims to make industrial-scale high-resolution brain mapping a standard tool for neuroscience

• David Cyranoski
• 16 August 2017

Neuroscientists who painstakingly map the twists and turns of neural circuitry through the brain are about to see their field expand to an industrial scale. A huge facility set to open in Suzhou, China, next month should transform high-resolution brain mapping, its developers say.

Where typical laboratories might use one or two brain-imaging systems, the new facility boasts 50 automated machines that can rapidly slice up a mouse brain, snap high-definition pictures of each slice and reconstruct those into a 3D picture. This factory-like scale will “dramatically accelerate progress”, says Hongkui Zeng, a molecular biologist at the Allen Institute for Brain Science in Seattle, Washington, which is partnering with the centre. “Large-scale, standardized data generation in an industrial manner will change the way neuroscience is done,” she says.

The institute, which will also image human brains, aims to be an international hub that will help researchers to map neural connectivity for everything from studies of Alzheimer’s disease to brain-inspired artificial-intelligence projects, says Qingming Luo, a researcher in biomedical imaging at the Huazhong University of Science and Technology (HUST) in Wuhan, China. Luo leads the new facility, called the HUST-Suzhou Institute for Brainsmatics, which has a 5-year budget of 450 million yuan (US$67 million) and will employ some 120 scientists and technicians. Luo, who calls himself a “brainsmatician”, also built the institute’s high-speed brain-imaging systems.

“There will be large demand, for sure,” says Josh Huang, a neuroscientist at Cold Spring Harbor Laboratory in New York, which is also partnering with the Chinese institute. Access to high-throughput, rapid brain mapping could transform neuro-scientists’ understanding of how neurons are connected in the brain, he says — just as high-throughput sequencing helped geneticists to untangle the human genome in the 2000s. “This will have a major impact on building cell-resolution brain atlases in multiple species,” he says.

Mammalian brains have millions of cells, and human brains even have billions. And the cells come in some 10,000 different types, marked by differences in shape, size and the genes they express. Neuroscientists hope that mapping out the structures and how they interact will help to reveal their functions (see Nature 548, 150–152; 2017). By comparing particular neuron types across multiple brains, scientists might be able to pick out the effects of a disease or a learned behaviour on cell structure, says Jürgen Goldschmidt, a brain-imaging researcher at the Leibniz Institute for Neuro-biology in Magdeburg, Germany.

But such maps often require months or years of effort. The process involves shaving centimetre-long mouse brains into 15,000 ultrathin slices with a diamond blade, staining each layer with chemicals or fluorescent tags to pick out particular features, imaging each layer with a microscope and then reconstructing the images into a 3D map.

High-speed mapping
That’s where Luo’s institute can help. Its vast number of machines have impressive speed and resolution, collaborators say. According to Zeng, the devices can gather the same amount of detail on a mouse brain in two weeks as would require months using other technologies, such as super-resolution confocal imaging.

Participants at a February meeting of the US BRAIN initiative (Brain Research through Advancing Innovative Neurotechnologies) in Bethesda, Maryland, were treated to a display of the technology’s capabilities when they were shown an image of a neuron that wrapped all of the way around a mouse brain (see Nature 543, 14–15; 2017). Allen Institute neuroscientist Christof Koch, whose team did the work in collaboration with Luo’s group, suggests the extensive reach of the neuron shows that the cell has a role in coordinating inputs and outputs across the brain to create consciousness.

The Suzhou institute will generate a huge amount of data: each mouse brain map alone will be 8 terabytes, Luo says. But the volume of a human brain is nearly 1,500 times that of a mouse brain; it would take a single machine around 20 years to digitally reconstruct one at the institute’s current rate. Luo aims to increase the speed of his machines and to use multiple devices in parallel.

Luo is keen for worldwide collaboration; along with the Allen Institute and Cold Spring Harbor Laboratory, Stanford University in California is forming a partnership with the centre. But Luo says that interest is so high that he won’t be able to accommodate everyone. “We are already turning people down.”

Nature 548, 268–269 (17 August 2017)
doi:10.1038/548268a


China launches brain-imaging factory : Nature News & Comment

 

[Martian2]

China's Top 10 Fabless Chipmakers

Who Are China's Biggest Fabless Chipmakers? | Electronic Design

"HiSilicon Semiconductors - $3.87 billion (¥26 billion)

The largest Chinese chip supplier is this subsidiary of Huawei, the smartphone giant and the world’s largest maker of telecommunications gear. Based in the Chinese city of Shenzhen, it sells silicon for surveillance cameras, displays, set-top boxes, and wireless modems."

 

[JSCh]

Graphene and phosphorus make fire-stopping foam
By Katrina Krämer
14 August 2017

Flame retardant hybrid material is light enough to sit on the petals of a flower

Source: American Chemical Society​

A lightweight but strong plastic almost twice as fire retardant as similar materials has been made by researchers in China and South Korea. The key to the material’s ability to keep flames at bay are small amounts of graphene combined with an element best known for its role in making, rather than stopping, fire: phosphorus.

The most widely used flame retardants are brominated compounds. However, they have been suspected to be toxic, particularly for children. As many countries move towards banning them altogether, scientists have been searching for alternatives. But in addition to being fire-retardant, materials need to be light and strong, as well as cheap and easy to produce on a large scale.

Jianxing Geng from the Chinese Academy of Sciences and colleagues have developed a non-burning polyimide foam that is strong enough to support a beaker of liquid weighing 6kg, but light enough to balance on a rose. Its flame-retardant properties come from 2% of red phosphorus-hybridised graphene – a combination of graphite and red phosphorus produced by ball milling.

The tiny phosphorus particles oxidise quickly when heated and promote char formation. Combined with graphene platelets, which are chemically stable even at high temperatures, the material forms an oxygen-proof layer on the surface. This stops the underlying material from burning.

Because polyimide foams are already made on industrial scale, Geng’s team thinks that scaling up the phosphorus graphene foam synthesis should also be feasible.

References
L Xu et al, ACS Appl. Mater. Interfaces, 2017, DOI: 10.1021/acsami.7b06282


Graphene and phosphorus make fire-stopping foam | Research | Chemistry World

 

[JSCh]

Public Release: 17-Aug-2017
Scientists identify central neural circuit for itch sensation
Chinese Academy of Sciences Headquarters

Itch-mediating spinal neurons, which express the gastrin-releasing peptide receptor (GRPR), are disynaptically connected to the parabrachial nucleus (PBN) via glutamatergic spinal projection neurons (PN).
Credit: SUN Yangang's lab

Itching is an unpleasant sensation associated with the desire to scratch, and the itch sensation is an important protective mechanism for animals. However, chronic itch, often seen in patients with skin and liver diseases, remains a challenging clinical problem as uncontrollable scratching causes severe skin and tissue damage.

Therapeutic approaches for chronic itch treatment have developed slowly due to the lack of knowledge about itch mechanisms. Therefore, the mechanism underlying itch signal processing is a key research area for both clinical and basic neuroscientists. Recent progress has strengthened the understanding of the molecular and cellular mechanisms underlying itch signal processing at the spinal level. However, how itch information is transmitted to the brain was largely unknown.

A recent study carried out by Dr. SUN Yangang's lab at the Institute of Neuroscience of the Chinese Academy of Sciences discovered a central neural circuit that is critical for transmitting the itch signal. By using optogenetic, chemogenetic, patch clamp recording, and in vivo fiber photometry techniques, the researchers demonstrated that the spino-parabrachial pathway plays a key role in transmitting itch signals from the spinal cord to the brain, and identified the parabrachial nucleus (PBN) as a first central relay for the itch sensation. The study was published in Science.

The researchers first investigated how the spinal itch-specific neurons send itch signals to the brain. Spinal neurons expressing gastrin-releasing peptide receptor (GRPR) have been shown to be crucial for itch signal processing. They found that the spinal GRPR neurons did not send the itch signal directly to the brain. Since the PBN is activated during itch processing, they postulated that the spinal GRPR neurons might be connected to the PBN poly-synaptically, and thus send itch information to the PBN indirectly.

To test this hypothesis, researchers constructed a transgenic mouse line and selectively expressed light-sensitive channels in GRPR neurons. Light-induced activation of the spinal GRPR neurons evoked excitatory postsynaptic responses in the spinal neurons that project to the PBN. This result demonstrated that spinal GRPR neurons activate the PBN via connection to the projection neurons, supporting their idea.

The researchers also examined whether the spino-parabrachial pathway plays a functional role in itch processing. By manipulating the spino-parabrachial pathway with optogenetics, they showed that inhibition of the spino-parabrachial pathway suppressed itch-induced scratching behavior.

In addition, researchers confirmed the functional role of PBN in itch processing. They showed that the activity of PBN neurons was elevated during itch processing. At the behavioral level, suppression of the activity of PBN neurons also reduced scratching behavior, suggesting that PBN plays a key role in itch processing.

In this study, researchers revealed a long-range neural circuit that is critical for transmitting itch signals from the spinal cord to the brain. Their findings suggest that the PBN represents a first critical central relay for the itch sensation. They have further shown that the PBN plays an important role in regulating scratching behavior in both acute and chronic itching. This study paves the way for further dissection of central circuit mechanisms underlying itch signal processing, and provides a potential target for therapeutic treatment of chronic itching.

###​

This work was supported by the Strategic Priority Research Program of the Chinese Academy of Sciences, the National Natural Science Foundation of China, Chinese Academy of Sciences Hundreds of Talented Program, and Youth Thousand Plan.



Scientists identify central neural circuit for itch sensation | EurekAlert! Science News

Di Mu, Juan Deng, Ke-Fei Liu, Zhen-Yu Wu, Yu-Feng Shi, Wei-Min Guo, Qun-Quan Mao, Xing-Jun Liu, Hui Li, Yan-Gang Sun. A central neural circuit for itch sensation, Science (2017). DOI: 10.1126/science.aaf4918.​

 

[JSCh]

Fullerene Device Acts as Both Solar Cell and a Current Inverter
By Dexter Johnson
Posted 17 Aug 2017 | 18:00 GMT

Illustration: Science Magazine​

An international team of researchers has developed a photovoltaic cell based on a combination of magnetic electrodes and C60 fullerenes— sometimes referred to as Buckyballs—that increases the photovoltaic efficiency of their device by 14 percent over photovoltaics using ordinary materials and architecture.

In research described in the journal Science, scientists from China, Germany, and Spain have taken spin valves—devices based on giant magnetoresistance and used in magnetic memory and sensors—and combined them with photovoltaic materials. The result offers a new way for solar cells to convert light into electricity.

“The device is simply a photovoltaic cell,” says Luis Hueso, research professor and leader of the Nanodevices Group at CIC nanoGUNE in Spain, in an e-mail interview with IEEE Spectrum. “However, we are using magnetic electrodes (cobalt and nickel-iron) rather than standard indium tin oxide (ITO) and aluminum as commonly used in organic photovoltaics.” The magnetic electrodes provide electrons with a certain orientation of their spin, creating what’s called a spin polarized current. Using these electrodes increased the photovoltaic efficiency by 14 percent compared to using ordinary electrodes, he says.

In order to achieve these results, the researchers needed the device to have both a photovoltaic effect and a spin transport effect. That is, the electrons keep their spin orientation as they cross the device, according to Hueso. “These two effects have not been observed before in the same device, only separately,” Hueso adds.

One of the byproducts of these simultaneous photovoltaic and spin-polarized effects is that the device they have developed has the added functionality of serving as an inverter, which is used to convert the direct current (DC) produced by solar cells into alternating current (AC).

Hueso explains that the current inversion is created by an external magnetic field. As the magnetic field changes, the current changes direction. The reason this works is that the current inside the device has two sources: one is the current generated by the light and the other is the current coming from the magnetic electrodes.

The current generated by the light can be changed by the amount of light irradiation. The current coming from the electrodes can be changed by the magnetic field. Balancing both contributions means the flow direction of the overall current can be modified.

The key to the functioning of the device is the C60 fullerene. The C60 is both a photovoltaic material and one that can sustain the spin polarization of the electronic carriers. “Since both effects had been demonstrated in the past—the spin one by our group—we decided to use it for a proof-of-principle experiment,” says Hueso.

The actual current output in the device is fairly small, mainly due to the fact that the C60 is not an great material for photovoltaics. To address this the researchers are currently working on building a similar device using better performing materials.

While Hueso recognizes more engineering would need to be done with the device they have produced, he believes that an actual device that acts as both a photovoltaic and an inverter could indeed be possible.


Fullerene Device Acts as Both Solar Cell and a Current Inverter - IEEE Spectrum

Xiangnan Sun, Saül Vélez, Ainhoa Atxabal, Amilcar Bedoya-Pinto, Subir Parui, Xiangwei Zhu, Roger Llopis, Fèlix Casanova, Luis E. Hueso. A molecular spin-photovoltaic device. Science (2017). DOI: 10.1126/science.aan5348
http://science.sciencemag.org/content/357/6352/677
​

 

[Martian2]

Leo Liu creates the ultimate evolution of the Segway. None of the Segway's drawbacks and all of the benefits.
----------

Meet The Futuristic Personal Transportation Vehicle Coming To China And U.S. Soon | Forbes

"Blizwheel is being billed as the world's smallest electric vehicle."