China Science & Technology Forum

[JSCh]

https://twitter.com/x/status/1216330739765194752

Nature✔@nature

Graphene could be used in many applications but high-quality films are difficult to synthesise as wrinkles tend to form. A study in Nature shows that protons can reduce wrinkle formation, enabling ultra-flat graphene films to be grown. https://go.nature.com/2R7l5Jg

 

[JSCh]

China build world's 1st low-frequency electromagnetic wave transmitting station - cnTechPost
Jan 12, 2020

China has recently built the world's first civilian low-frequency high-power electromagnetic wave launching station, with a detection radius of thousands of kilometers and a detection depth of ten kilometers, which can be used for earthquake prediction, according to Xinhua News Agency.

The project was advanced without similar foreign projects for reference, forming a high-signal-to-noise ultra-low frequency electromagnetic wave signal source that can cover Chinese territory and territorial waters.

In addition to being the world's first civilian low-frequency high-power electromagnetic wave transmitting station, the project also built the first seismic monitoring network that can receive artificial and natural source low-frequency electromagnetic signals at the southern end of the capital circle and the north-south seismic belt.

The extremely low frequency data engineering center established by it has built a high-performance data computing and shared service platform for resource detection, earthquake prediction and other cutting-edge technology research.

In addition, it has also carried out exploratory scientific experimental research on earthquake prediction and underground minerals, oil and gas resources exploration, and continental shelf exploration, and has made many breakthroughs, providing advanced scientific research in related fields such as "deep ground, deep sea, and deep space" New technological means and platforms.

"The acceptance of the project marks the birth of another innovative scientific platform in China," said the relevant person in charge of the Seventh Research Institute of China Shipbuilding Corporation, which is in charge of the project.

He said that extremely low frequency electromagnetic waves can penetrate thicker strata and deeper seawater and can be used for research and application in the fields of stratum structure, detection of underground resources and seabed resources, and earthquake prediction. Therefore, the results obtained by the project have great strategic significance.

 

[JSCh]

NEWS AND VIEWS * 15 JANUARY 2020
Transparent crystals with ultrahigh piezoelectricity
It has been difficult to make transparent materials that have extremely high piezoelectricity — a useful property related to the coupling of electric fields and mechanical strain. This hurdle has now been overcome.

Jurij Koruza

Piezoelectric materials show high electromechanical coupling, which means that they can generate large strains if an electric field is applied to them, and can transform external mechanical stimuli into electric charge or voltage1. They are widely used in electronic applications, including sensors, small motors and actuators — devices that convert electrical energy into movement. In addition, their high energy efficiency and ease of miniaturization are driving the development of new technologies, such as energy harvesters for the growing network of Internet-connected devices known as the Internet of Things, actuators for touch screens and microrobots. Writing in Nature, Qiu et al.2 report the preparation of high-performance piezoelectrics that have the long-desired property of near-perfect transparency to light. This breakthrough could lead to devices that combine excellent piezo-electricity with tunable optical properties.


....

Transparent crystals with ultrahigh piezoelectricity | Nature

 

[Han Patriot]

China build world's 1st low-frequency electromagnetic wave transmitting station - cnTechPost
Jan 12, 2020

China has recently built the world's first civilian low-frequency high-power electromagnetic wave launching station, with a detection radius of thousands of kilometers and a detection depth of ten kilometers, which can be used for earthquake prediction, according to Xinhua News Agency.

The project was advanced without similar foreign projects for reference, forming a high-signal-to-noise ultra-low frequency electromagnetic wave signal source that can cover Chinese territory and territorial waters.

In addition to being the world's first civilian low-frequency high-power electromagnetic wave transmitting station, the project also built the first seismic monitoring network that can receive artificial and natural source low-frequency electromagnetic signals at the southern end of the capital circle and the north-south seismic belt.

The extremely low frequency data engineering center established by it has built a high-performance data computing and shared service platform for resource detection, earthquake prediction and other cutting-edge technology research.

In addition, it has also carried out exploratory scientific experimental research on earthquake prediction and underground minerals, oil and gas resources exploration, and continental shelf exploration, and has made many breakthroughs, providing advanced scientific research in related fields such as "deep ground, deep sea, and deep space" New technological means and platforms.

"The acceptance of the project marks the birth of another innovative scientific platform in China," said the relevant person in charge of the Seventh Research Institute of China Shipbuilding Corporation, which is in charge of the project.

He said that extremely low frequency electromagnetic waves can penetrate thicker strata and deeper seawater and can be used for research and application in the fields of stratum structure, detection of underground resources and seabed resources, and earthquake prediction. Therefore, the results obtained by the project have great strategic significance.

This can be used for submarine detection

 

[JSCh]

NEWS * 16 JANUARY 2020
Supercomputer scours fossil record for Earth’s hidden extinctions
Palaeontologists have charted 300 million years of Earth’s history in breathtaking detail.

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Trilobites disappeared from the fossil record during the mass extinction at the end of the Permian period, 252 million years ago.Credit: Shutterstock

Palaeontologists have a fuzzy view of Earth’s history. An incomplete fossil record and imprecise dating techniques make it hard to pinpoint events that happened within geological eras spanning millions of years. Now, a period that saw a boom in animal complexity and one of Earth’s greatest mass extinctions is coming into sharp focus.

Using the world’s fourth most powerful supercomputer, Tianhe II, a team of scientists based mostly in China mined a database of more than 11,000 fossil species that lived from around 540 million to 250 million years ago. The result is a history of life during this period, the early Palaeozoic era, that can pinpoint the rise and fall of species during diversifications and mass extinctions to within about 26,000 years. It is published on 16 January in Science1.

“It is kind of amazing,” says Peter Wagner, a palaeontologist and evolutionary biologist at the University of Nebraska–Lincoln, who was not involved in the work. Being able to look at species diversity on this scale is like going from a system where “people who lived in the same century are considered to be contemporaries, to one in which only people who lived during the same 6-month period are deemed to be contemporaries”, he writes in an essay accompanying the study2.

Such a view, Wagner adds, will help scientists to identify the causes of mass extinctions — such as the event at the end of the Permian period, some 252 million years ago, that wiped out more than 95% of marine species — as well as understand less dramatic species die-offs and rebounds that have been hard to uncover because of gaps in the fossil record. Understanding these processes could reveal parallels to the planet’s current loss of biodiversity.

Patchy record
Most organisms in Earth’s history didn’t leave fossils, and scientists have identified only a tiny fraction of those that did. As a result, it can be hard to tell whether changes in the fossil record mark real shifts, such as mass extinctions, or are simply caused by a lack of fossil finds.

In the 1960s, palaeontologists began analysing the fossil record systematically, revealing multiple mass extinctions and periods during which life flourished. But these and later efforts could usually pinpoint biodiversity changes only to within about ten million years, because fossils were lumped into relatively long geological periods and analysed en masse.

To improve on this, a team led by palaeontologist Jun-xuan Fan at Nanjing University in China created and analysed a database of fossil marine invertebrate species that were found in more than 3,000 layers of rock, mostly from China but representing geology across the planet during the early Palaeozoic. The group then used software to measure when individual species had emerged and gone extinct.

The program took advantage of the fact that species were usually found in multiple rock formations — each spanning hundreds of thousands to millions of years — and used this information to place upper and lower limits on the period in which the species actually existed. The effort revealed for how long, and in what order, all 11,000 species had existed. It took the supercomputer around seven million processor hours.

Extinctions elucidated
Using this approach, the team was able to learn extra details about well-documented events, such as the end-Permian extinction and the Cambrian explosion in animal diversity around 540 million years ago. The analysis showed, for instance, that species diversity declined in the 80,000 years leading up to the end-Permian mass extinction, which itself occurred over around 60,000 years.

The findings also cast doubt on the existence of a smaller-scale die-off known as the end-Guadalupian extinction, which is thought to have wiped out many marine species around 260 million years ago. That was the biggest surprise, says Mike Benton, a palaeontologist at the University of Bristol, UK, who has documented changes in vertebrate diversity during that period. The study, he adds, “represents a pretty amazing big-data endeavour”.

Benton hopes to see the effort extended to later periods — particularly the past 100 million years. Palaeontologists disagree over whether an apparent increase in animal diversity in this period is the result of sampling bias. “This last 100 million years has been at the heart of a long-running debate about ‘pull of the recent’ and discriminating between real signal and bias,” Benton says.

Norman MacLeod, a palaeontologist at the University of Nanjing and a co-author of the study, says the team’s work might help to reveal the underlying causes of changes in biodiversity, by charting its ups and downs on a timescale that can be matched with environmental and climatic shifts.

Wagner adds that the team’s approach will be most valuable in uncovering — and explaining — smaller-scale extinctions, not dissimilar to those occurring today. Such extinctions could turn out to be “a bad 100,000 years, or a bad week” for some groups of organisms but not others, he says. “When you get this resolution, it starts opening the doors to actually testing what the smaller-turnover events might be like.”


Supercomputer scours fossil record for Earth’s hidden extinctions | Nature

Jun-xuan Fan, Shu-zhong Shen, Douglas H. Erwin, Peter M. Sadler, Norman MacLeod, Qiu-ming Cheng, Xu-dong Hou, Jiao Yang, Xiang-dong Wang, Yue Wang, Hua Zhang, Xu Chen, Guo-xiang Li, Yi-chun Zhang, Yu-kun Shi, Dong-xun Yuan, Qing Chen, Lin-na Zhang, Chao Li, Ying-ying Zhao. A high-resolution summary of Cambrian to Early Triassic marine invertebrate biodiversity. Science (2020). DOI: 10.1126/science.aax4953​

 

[JSCh]

Shanghai scientists detail protein responsible for TB
By Wang Ying in Shanghai | China Daily | Updated: 2020-01-17 08:45

[Photo/IC]

Scientists in Shanghai have discovered a smart protein secreted by Mycobacterium tuberculosis (MTB), which is responsible for the development of tuberculosis, an infectious disease that has been back on the rise globally partly due to a stagnation in medical research for its cure.

The discovery, published on the website of the UK-based journal Nature on Thursday, was led by a research team headed by Ge Baoxue, a professor from the School of Medicine at Tongji University, and Rao Zihe, an academician from Shanghai Tech University.

After nearly a decade of research, the team found that the protein secreted by MTB can mislead the signal of the human body to attack its own immune system and eventually lead to the development of TB.

The discovery not only offers a new perspective for understanding the infection of the disease, but also paves the way for the accurate development of targeted drugs as it provides a more precise target for follow-up drug development, said Ai Kaixing, head of the Shanghai Pulmonary Hospital affiliated to Tongji University.

TB is an infectious disease usually caused by MTB bacteria.

Traditionally, its treatment requires the use of multiple antibiotics over a long period of time, but antibiotic resistance is a growing problem with increasing rates of drug-resistant TB.

According to Ge, contrary to the general notion that TB has been eliminated, the disease is alive and thriving due to a lack of new drugs to cure it.

"Our research discovered that TB infection has been on the rise worldwide over the past few years," Ge said. "The World Health Organization reported the number of newly diagnosed patients amounted to 10.4 million in 2018, and 1.4 million people died of the disease that year."

In China alone, 550 million people are infected, including 5 million active infections, according to Ge.

"The widely applied TB drugs are seeing a rise in multi-drug resistances, making the treatment of the disease increasingly difficult," Ge said.

There were 480,000 people globally-including 120,000 in China-who reported multi-drug resistance in 2018. Multi-drug resistance has significantly pushed up the cost for treatment worldwide from $1,000 per person to $20,000 per person, Ge added.

 

[JSCh]

https://twitter.com/x/status/1219152620339769345

Science Magazine✔@sciencemagazine

A new Science study details a system that concentrates hydrogen peroxide and methane in close proximity for efficient methanol synthesis, which represents a step toward the application of direct activation of methane to produce valuable products. ($) https://fcld.ly/dsnxcmw



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3:00 PM - Jan 20, 2020

 

[JSCh]

Academy supports more labs for frontier science
By Zhang Zhihao | China Daily | Updated: 2020-01-21 09:14

A file photo shows the Shanghai Synchrotron Radiation Facility (SSRF) project that was put into service on Jan 19, 2010. [Photo/shb.cas.cn]

The Chinese Academy of Sciences will support more labs and major projects in frontier sciences, expand international collaboration with other countries and share its data and solutions via more robust and open cloud-based platforms this year, senior scientists said on Friday.

CAS will spend more than 7.7 billion yuan ($1.1 billion) to build four new major scientific instruments, including the world's largest high-energy synchrotron radiation light source, in Beijing's Huairou district, CAS President Bai Chunli said during an annual working meeting on Friday.

Moreover, it will spend another 2.7 billion yuan to build 11 scientific and educational facilities in the districts. All of these projects had been launched by the end of last year, Bai said. The academy will also build new labs in Shanghai, Hefei in Anhui province, the Xiongan New Area in Hebei province and the Guangdong-Hong Kong-Macao Greater Bay Area.

"This year is a momentous year for China in eliminating poverty to build a moderately prosperous society," Bai said. "For CAS, this year marks the end of the first phase of the Pioneering Initiative, so it is a year to review the past and prepare for the future."

In 2013, President Xi Jinping asked the academy to be a pioneer in four major areas-making great scientific and technological progress, producing more innovative talent and becoming an influential scientific think tank for China as well as a world-class research institution. The Pioneering Initiative was launched a year later consisting of plans and reforms to meet Xi's four expectations by 2030.

"Our priorities this year will focus on further improving our research capabilities and producing original breakthroughs in basic research," Bai said, adding that more capable State laboratories, advanced research projects and open sharing platforms will be instrumental in fulfilling these goals.

By the end of last year, the academy had launched 58 pilot projects in fields such as space technology, green industry and regenerative medicine, said Xiang Libin, the academy's vice-president responsible for managing these projects. "These projects not only are crucial for producing globally influential breakthroughs, they are also closely related to our societal well-being," he said.

In terms of international collaboration, the academy has signed institutional-level cooperation agreements with 174 foreign institutions from 61 countries. Around 4,000 foreign scientists, as well as 1,600 graduate students, are currently visiting, working or studying at the academy, said Zhang Yaping, the academy's vice-president responsible for global cooperation.

The Alliance of International Science Organizations, a global scientific organization launched by the academy in 2018 to promote research collaboration and sustainable development, gained 15 new members last year, reaching a total of 52 research institutions and organizations, Zhang said.

Zhang said the Chinese academy has made considerable breakthroughs with scientifically developed countries last year. For example, the Academy of Sciences Leopoldina in Germany signed a declaration with CAS, its first supporting basic scientific research with a foreign academy since its founding in 1652.

China-US scientific cooperation on the government level has stagnated due to friction between the countries, but on the academic and civilian levels, such collaboration is alive and well, Zhang added.

"More and more American scientists are beginning to realize that sustained dialogue and cooperation with Chinese peers will benefit both countries in the long run," he said. "I believe the two scientific communities from both countries have the wisdom and capability to address current challenges and continue to contribute to the betterment of mankind."

Chinese scientists have also offered their expertise and equipment to provide safe drinking water to around 4,000 villagers and 1,300 students in Sri Lanka. Disaster mitigation, environmental protection, food safety and public health are some of the top fields for international cooperation, Zhang said.

Li Shushen, CAS's vice-president, said the academy has launched a new version of its scientific cloud database and it is open for researchers around the world to use its plethora of features, including cloud calculation, data search and storage, analytical software and community networking.

The network includes scientific data on energy, oceanography, biosciences, health and other frontier and interdisciplinary fields, according to Li.

"It is a cloud service by the scientists, so they can promote open and global cooperation," Li said.

 

[JSCh]

EWS RELEASE 5-FEB-2020
New droplet-based electricity generator: A drop of water generates 140V power, lighting up 100 LED bulbs
CITY UNIVERSITY OF HONG KONG

Generating electricity from raindrops efficiently has gone one step further. A research team led by scientists from the City University of Hong Kong (CityU) has recently developed a droplet-based electricity generator (DEG), featured with a field-effect transistor (FET)-like structure that allows for high energy-conversion efficiency and instantaneous power density increased by thousands times compared to its counterparts without FET-like structure. This would help to advance scientific research of water energy generation and tackle the energy crisis.

The research was led together by Professor Wang Zuankai from CityU's Department of Mechanical Engineering, Professor Zeng Xiao Cheng from University of Nebraska-Lincoln, and Professor Wang Zhong Lin, Founding Director and Chief Scientist from Beijing Institute of Nanoenergy and Nanosystems of Chinese Academy of Sciences. Their findings were published in the latest issue of the highly prestigious scientific journal Nature, titled "A droplet-based electricity generator with high instantaneous power density".


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New droplet-based electricity generator: A drop of water generates 140V power, lighting up 100 LED bulbs | EurekAlert! Science News

 

[JSCh]

Branching out for a new green revolution
7 February 2020

Researchers at the University of Oxford and the Chinese Academy of Sciences have discovered a new gene that improves the yield and fertilizer use efficiency of rice.

The worldwide late-20th century ‘Green Revolution’ saw dramatic year-by-year increases in global grain yields of rice and other cereals. The Green Revolution was fueled by new high-yielding dwarfed Green Revolution Varieties (GRVs) that are still in widespread use today, and by increased fertilizer use.

The numbers of grain-bearing branches (‘tillers’) per plant are increased in GRVs, and further enhanced by increased nitrogen fertilizer use, thus boosting grain yield. However, fertilizers are costly to farmers and cause extensive environmental damage. Developing new GRVs combining increased tiller number and grain yield with reduced nitrogen use is thus an urgent global sustainable agriculture goal.

Soil Nitrogen Promotes Rice Branching (Photo credit: Kun Wu/Xiangdong Fu, Chinese Academy of Sciences)

A major new study, published today as the cover story of journal Science, led by Professor Xiangdong Fu from the Chinese Academy of Sciences’ Institute of Genetics and Developmental Biology, and Professor Nicholas Harberd from the Department of Plant Sciences at the University of Oxford, part-funded by the BBSRC-Newton Rice Initiative, has for the first time discovered a gene that can help reach that goal.

The study identified a rice gene that responds to nitrogen, and hence increases the accumulation in plant cells of a protein called NGR5. Nitrogen-stimulated NGR5 accumulation then alters the structure of genes that inhibit tiller growth, switching them off and thus increasing the numbers of yield-enhancing tillers.

Professor Harberd said: ‘Discovering how nitrogen stimulates tiller growth was exciting in itself. But our discovery was particularly exciting because NGR5 controls the activity (via a mechanism known as chromatin modulation) of multiple genes in the rice genome, genes likely responsible for many different rice responses to soil nitrogen in addition to tiller growth.’​

The increased tiller number of GRVs is also caused by accumulation of another branching-promoting protein called DELLA, an accumulation that is reduced by the plant hormone gibberellin (GA). The study found that GA also reduces NGR5 accumulation, and that tiller growth is the product of complex interactions between the NGR5 and DELLA proteins.

Professor Harberd said: ‘We next reasoned that further increase in the accumulation of NGR5 might increase tiller number and yield with reduced fertilizer use. To our delight, we found that increasing NGR5 accumulation caused an increase in both tiller number and grain yield of a current elite rice GRV, especially at low fertilizer levels.’

The researchers say NGR5 should now become a major target for plant breeders in enhancing crop yield and fertilizer use efficiency, with the aim of achieving the global grain yield increases necessary to feed a growing world population at reduced environmental cost.

Professor Harberd added: ‘This study is a prime example of how pursuing fundamental plant science objectives can lead rapidly to potential solutions to global challenges. It discovers how plants coordinate their growth in response to soil nitrogen availability, then shows how that discovery can enable breeding strategies for sustainable food security and future new green revolutions.’


Branching out for a new green revolution | Department of Plant Sciences | University of Oxford

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[JSCh]

Brain cells called microglia eat away mice’s memories
A new study offers clues on how we forget

In a mouse’s hippocampus, brain cells known as microglia (red) can eliminate connections between nerve cells (blue) that are thought to store some types of memories.

CHAO WANG

By Laura Sanders
FEBRUARY 6, 2020 AT 2:00 PM

Immune cells in the brain chew up memories, a new study in mice shows.

The finding, published in the Feb. 7 Science, points to a completely new way that the brain forgets, says neuroscientist Paul Frankland of the Hospital for Sick Children Research Institute in Toronto, who wasn’t involved in the study.

That may sound like a bad thing, but forgetting is just as important as remembering. “The world constantly changes,” Frankland says, and getting rid of unimportant memories — such as a breakfast menu from two months ago — allows the brain to collect newer, more useful information.

Exactly how the brain stores memories is still debated, but many scientists suspect that connections between large groups of nerve cells are important (SN: 1/24/18). Forgetting likely involves destroying or changing these large webs of precise connections, called synapses, other lines of research have suggested. The new result shows that microglia, immune cells that can clear debris from the brain, “do exactly that,” Frankland says.

Microglia are master brain gardeners that trim extra synapses away early in life, says Yan Gu, a neuroscientist at Zhejiang University School of Medicine in Hangzhou, China. Because synapses have a big role in memory storage, “we started to wonder whether microglia may induce forgetting by eliminating synapses,” Gu says.

Gu’s team first gave mice an unpleasant memory: mild foot shocks, delivered in a particular cage. Five days after the shocks, the mice would still freeze in fear when they were placed in the cage. But 35 days later, they had begun to forget and froze less often in the room.

Next, the researchers used a drug to get rid of microglial cells in some mice’s brains. Mice with fewer microglia froze more in the cage than mice with normal numbers of microglia, indicating that those rodents held on to the scary memory. The same was true of mice with microglia that, thanks to a drug, were unable to gobble up synapses. Those mice also seemed to hold on to the memory, the researchers found.

The study also hints at which memories are particularly vulnerable. Scientists marked the nerve cells that stored the fearful memory with a glowing dye and gave the mice a drug that kept these memory-holding cells silent, unable to fire off signals. These unused, silent memories seemed to be more susceptible to microglia. That finding suggests that “less-revisited memories are easier to remove,” Gu says.

The results come from one particular type of memory: a fearful one, and one that’s stored in the hippocampus. That brain structure is thought to be an early, temporary stop before memories move to longer-term storage. Researchers don’t yet know whether microglia would have a similar effect on memory-related synapses elsewhere in the brain. Microglial synapse-culling has been tied to the early stages of Alzheimer’s disease (SN: 3/31/16).

Also unclear is why some old memories — ones not recalled for years — survive. The related synapses may be extra durable, or maybe those memories are stored where microglia are less active, Gu says. Or perhaps people do revisit these memories and keep them strong, even if they’re not aware of it.

Other overlapping explanations for forgetting exist, such as the behavior of certain proteins and the creation of new nerve cells, as Frankland’s work has suggested (SN: 5/8/14). These ideas involve synapses changing with time. “All of these could conceivably be natural forgetting mechanisms,” Frankland says.

Questions or comments on this article? E-mail us at feedback@sciencenews.org

CITATIONS
C. Wang et al. Microglia mediate forgetting via complement-dependent synaptic elimination. Science. Vol. 367, February 7, 2020, p. 688. doi:10.1126/science.aaz2288.​

Brain cells called microglia eat away mice’s memories | Science News

 

[Beast]

 

[JSCh]

Fast-charging, long-running, bendy energy storage breakthrough | University College London
17 February 2020

A new bendable supercapacitor made from graphene, which charges quickly and safely stores a record-high level of energy for use over a long period, has been developed and demonstrated by UCL and Chinese Academy of Sciences researchers.

While at the proof-of-concept stage, it shows enormous potential as a portable power supply in several practical applications including electric vehicles, phones and wearable technology.

The discovery, published today in Nature Energy, overcomes the issue faced by high-powered, fast-charging supercapacitors – that they usually cannot hold a large amount of energy in a small space.

First author of the study, Dr Zhuangnan Li (UCL Chemistry), said: “Our new supercapacitor is extremely promising for next-generation energy storage technology as either a replacement for current battery technology, or for use alongside it, to provide the user with more power.

“We designed materials which would give our supercapacitor a high power density – that is how fast it can charge or discharge – and a high energy density – which will determine how long it can run for. Normally, you can only have one of these characteristics but our supercapacitor provides both, which is a critical breakthrough.

“Moreover, the supercapacitor can bend to 180 degrees without affecting performance and doesn’t use a liquid electrolyte, which minimises any risk of explosion and makes it perfect for integrating into bendy phones or wearable electronics.”

A team of chemists, engineers and physicists worked on the new design, which uses an innovative graphene electrode material with pores that can be changed in size to store the charge more efficiently. This tuning maximises the energy density of the supercapacitor to a record 88.1 Wh/L (Watt-hour per litre), which is the highest ever reported energy density for carbon-based supercapacitors.

Similar fast-charging commercial technology has a relatively poor energy density of 5-8 Wh/L and traditional slow-charging but long-running lead-acid batteries used in electric vehicles typically have 50-90 Wh/L.

While the supercapacitor developed by the team has a comparable energy density to state-of-the-art value of lead-acid batteries, its power density is two orders of magnitude higher at over 10,000 Watt per litre.

Senior author and Dean of UCL Mathematical & Physical Sciences, Professor Ivan Parkin (UCL Chemistry), said: “Successfully storing a huge amount of energy safely in a compact system is a significant step towards improved energy storage technology. We have shown it charges quickly, we can control its output and it has excellent durability and flexibility, making it ideal for development for use in miniaturised electronics and electric vehicles. Imagine needing only ten minutes to fully-charge your electric car or a couple of minutes for your phone and it lasting all day.”

The researchers made electrodes from multiple layers of graphene, creating a dense, but porous material capable of trapping charged ions of different sizes. They characterised it using a range of techniques and found it performed best when the pore sizes matched the diameter of the ions in the electrolyte.

The optimised material, which forms a thin film, was used to build a proof-of-concept device with both a high power and high energy density.

The 6cm x 6cm supercapacitor was made from two identical electrodes layered either side of a gel-like substance which acted as a chemical medium for the transfer of electrical charge. This was used to power dozens of light-emitting diodes (LEDs) and was found to be highly robust, flexible and stable.

Even when bent at 180 degrees, it performed almost same as when it was flat, and after 5,000 cycles, it retained 97.8% of its capacity.

Senior author, Professor Feng Li (Chinese Academy of Sciences), said: “Over the next thirty years, the world of intelligent technology will accelerate, which will greatly change communication, transportation and our daily lives. By making energy storage smarter, devices will become invisible to us by working automatically and interactively with appliances. Our smart cells are a great example of how the user experience might be improved and they show enormous potential as portable power supply in future applications.”

The study was funded by the National Science Foundation of China, the Ministry of Science and Technology of China, the Chinese Academy of Science and the EPSRC.

 

[JSCh]

NEWS RELEASE 20-FEB-2020
Scientists use light to convert fatty acids into alkanes
CHINESE ACADEMY OF SCIENCES HEADQUARTERS

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Schematic representation of photocatalytic decarboxylation strategy for alkane production from biomass-derived fatty acids. CREDIT: HUANG Zhipeng

Researchers led by Prof. WANG Feng at the Dalian Institute of Chemical Physics (DICP) of the Chinese Academy of Sciences have reported that photocatalytic decarboxylation is an efficient alternate pathway for converting biomass-derived fatty acids into alkanes under mild conditions of ambient temperature and pressure. This finding was published in Nature Catalysis on Feb. 19.

Long-chain alkanes are the major component of diesel and jet fuel. Therefore, production of these alkanes from renewable biomass, such as biomass-derived fatty acids instead of fossil resources, is important for developing a sustainable energy supply. However, most established catalytic systems require harsh operating conditions (i.e., high temperature and pressure) and excessive H2 consumption.

The researchers found that under illumination, the decarboxylation of fatty acids could be easily induced by photo-generated holes on the semiconductor TiO2, subsequently generating alkyl radical intermediates.

However, due to the uncontrollable reactivity of alkyl radicals, the production of desired alkanes was characterized by low selectivity. "Rationally controlling the conversion of radical intermediates for preferential hydrogen termination is the key to high selectivity in obtaining alkane products," said Prof. WANG.

The scientists discovered that when exposing the catalyst Pt/TiO2 to H2 atmosphere with light, the interaction between the catalyst and H2 generated a hydrogen-rich surface, so photo-generated radicals could be rapidly terminated by surface hydrogen species, thus greatly inhibiting oligomerization.

These results show that Cn-1 alkanes can be obtained from biomass-derived C12-C18 fatty acids in high yields (greater than or equal to 90%) under mild conditions (30 °C, H2 pressure less than or equal to 0.2 MPa) with 365 nm LED irradiation. Moreover, the average production rates are comparable to those of thermocatalytic systems operating under harsh reaction conditions.

Tall oil and soybean fatty acids are the low-value byproducts of the pulp and soybean oil refining industries, respectively. The researchers conducted conversion of these two industrial fatty acid mixtures, obtaining alkane products in high yields (up to 95%).

"Such a green and environmentally friendly process is promising. It bridges photosynthetic chemistry and industrial catalysis, and extends the photoenergy utilization chain. It is particularly promising considering the abundant available low-quality fatty acids in China," said WANG.



Scientists use light to convert fatty acids into alkanes | EurekAlert! Science News

 

[Pepsi Cola]

What a time to stay at home or in the labs to do experiments!