China Science & Technology Forum

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EarthLab Makes Debut at Hong Kong InnoTech Expo 2017
Sep 25, 2017

CAS Vice President ZHANG Jie visits the booth of EarthLab. (Image by IAP)​

EarthLab, an earth system science simulator developed by Chinese research team led by CAS Institute of Atmospheric Physics (IAP), makes debut at Hong Kong InnoTech Expo 2017, a showcase of achievements in science and technology of the Chinese mainland and Hong Kong. Sponsored by Our Hong Kong Foundation, the Expo will run from 24 sept to 2 Oct. 2017.

EarthLab is a numerical simulation system of the main Earth systems, developed by the IAP, Sugon, Tsinghua University, and the National Satellite Meteorological Center.

The comprehensive technical level of EarthLab will rank among its counterparts in the United States, Japan and Europe, according to scientists.

The system can help explore the impact of each system and its interaction with the Earth system as a whole, as well as the regional environment in China; integrate simulations and observation data to improve the accuracy of forecasting; improve the prediction and projection skills for climate change and air pollution; provide a numerical simulation platform to take Earth system research in China to the top level internationally; and support China's disaster prevention and mitigation, climate change, and atmospheric environment governance, along with other major issues.

At the booth of EarthLab, Visitors can observe and even “touch” simulation of dust/pollutant transportation, solar activities, land surface change, ocean circulation and other earth systems at the booth of EarthLab by means like augmented reality (AR) and other interactive science.

Participants at the opening ceremony include TUNG Chee-hwa, President of Our Hong Kong Foundation, Carrie Lam Cheng Yuet-ngor, Chief Executive of Hong Kong Special Administrative Region and WAN Gang, Minister of Science and Technology. With the theme "Displaying China's Civilization of Technology and Its Latest Innovation," nearly 130 exhibits are showcased at the event, and the organizer is expecting 100,000 guests this year.

EarthLab will be accommodate in the Huairou Campus of the Chinese Academy of Sciences in Beijing. Construction of the site will begin in 2018 and is expected to be completed by 2021.

​

Visitors watch the video of EarthLab introduction on the screen on one of the walls of the model of prototype of EarthLab. (Image by IAP)



EarthLab Makes Debut at Hong Kong InnoTech Expo 2017---Chinese Academy of Sciences

 

[JSCh]

Long-Lasting Qubits Share Vibrations to Stay Cool
By Charles Q. Choi
Posted 25 Sep 2017 | 15:00 GMT

Illustration: Tsinghua University/Nature Photonics​

A quantum computer can theoretically vastly outperform a normal computer, but until now its basic component, known as a qubit, could only remain stable for less than a minute. Now scientists in China have developed single qubits that could remain coherent for about 10 minutes. These magnetically trapped qubits could someday become an essential component of quantum computers and quantum networks.

The quantum effect known as superposition permits a particle to essentially spin in two opposite directions at once, or exist in two or more places simultaneously. Using superposition, qubits can symbolize data as both a one and zero at the same time, whereas transistors in standard computers are each limited to representing data as single digits. When qubits are linked or entangled together, they can help perform exponentially more computations than a comparable number of transistors.

But qubits are only useful if their superpositions can stay coherent or stable. More than 20 years ago, scientists found they could achieve coherence times of roughly 10 minutes with ensembles of magnetically trapped ions. However, unexpectedly, when it came to single qubits, researchers were cursed with much shorter coherence times. Until now, the best coherence time they could accomplish was less than one minute with solitary magnetically trapped ions.

Now scientists at Tsinghua University in Beijing have achieved a coherence time of more than 10 minutes for a single qubit consisting of a magnetically trapped, positively charged ytterbium-171 ion.

"What we have demonstrated is basically how the memory zone for quantum memory, one essential part of a quantum computer, can be physically implemented," says study senior author Kihwan Kim, a quantum physicist at Tsinghua University.

Kim says the reason that prior experiments with ensembles of ions were able to achieve long coherence times was because they were performed using large magnetic traps, whereas previous research with single ions used much smaller magnetic traps. As such, the electrodes used to analyze the ensembles were relatively far away, while the electrodes used to analyze the single ions were much closer. This meant the amount of heat the ensembles experienced from the vibrational motion of atoms in the electrodes was a few million times less than what the single ions felt, Kim says. Such heat can disrupt coherence.

In order to keep their qubits relatively cool, the scientists placed a positively charged barium-138 ion in the same magnetic trap with each ytterbium-171 ion. Whenever the barium-138 ion collides with the ytterbium-171 in the trap, it absorbs some of its vibrational motion, cooling it down.

"Before us, no one performed such 'sympathetic cooling' for single ions to observe long coherence times in a trap for quantum information processing," Kim says.

The researchers also suppressed the level of disruptive noise that each single qubit experienced from fluctuations in the magnetic fields used to trap them. This also helped prolong their coherence time. The scientists detailed their findings today in the journal Nature Photonics.

The group is now exploring ways to further reduce noise in their system, such as by installing a shield to protect ions from those magnetic field fluctuations. Kim notes, "the coherence time after we eliminate the heating problem is still limited to 10 minutes. We are not yet fully sure the main reason for this limitation."


Long-Lasting Qubits Share Vibrations to Stay Cool - IEEE Spectrum

Ye Wang, Mark Um, Junhua Zhang, Shuoming An, Ming Lyu, Jing-Ning Zhang, L.-M. Duan, Dahyun Yum & Kihwan Kim. Single-qubit quantum memory exceeding ten-minute coherence time. Nature Photonics (2017). DOI: 10.1038/s41566-017-0007-1​

 

[JSCh]

A blueprint to a science city that will rival Silicon Valley
By Li Xinran | 00:01 UTC+8 September 12, 2017 |

Print Edition

View attachment 424719
Shanghai Synchrotron Radiation Facility​

THE recently released “Construction Plan of Zhangjiang Science City” revealed that the high-tech park will become an administrative subdistrict, as part of a national strategy to establish Zhangjiang Comprehensive National Scientific Center.

According to the blueprint, Zhangjiang will have a central region along Chuanyang River, an artificial branch of Huangpu River, to be home to a batch of national-level laboratories and scientific projects along with various public services for employees and residents.

The science city has ambitions to be on a par with California’s Silicon Valley, Singapore’s One North Science Park and Japanese Tsukuba scientific town. And it will establish a basic framework for a comprehensive national scientific center by 2020.

To achieve that goal the world’s top innovative professionals, national scientific facilities, leading universities, research institutes and research and development centers of multinational enterprises will be looked at.

To make Zhangjiang a top attraction for talented researchers, the local government provides vigorous support with a series of complementary policies. Scientists will be ensured to receive excellent services and enjoy a supportive environment for research.

As part of the policies, around 9.2 million square meters of residential buildings will be built. About 96 percent of them will only be available for rental, according to the Shanghai Planning, Land and Resources Administration.

The first phase construction of apartments for rent will be launched at Sunqiao. As part of the future international community, it occupies an area of 65,000 square meters. A total of 1,226 well-furnished condos will be available after the construction is completed.

Subway and bus lines will run through the science city to connect office buildings, renovated factory houses and innovation parks for startups. More expressways to link to Shanghai’s railway stations, airports, and downtown areas have also been planned.

Schools and other public facilities will be built to serve residents, most of whom are scientists, research fellows, senior executives and their families.

The science city will be surrounded by a greenbelt. Continuous paths for walking and cycling along the Chuanyang River, small parks and public plazas will be built within the area.

It aims to attract 500 renowned scientists and experts by the end of 2020. Over 20,000 professionals from abroad and overseas graduates will work in Zhangjiang by then, according to the Pudong New Area government.

The authority has announced the establishment of the Administration of Overseas Talent to offer a one-stop service for overseas professionals along with a batch of new policies to ease green card and work permit rules.

The foreign talent recommended by the Zhangjiang or Shanghai Free Trade Zone management committee, for instance, can enjoy a fast track system to apply for the Chinese green card, or foreigners’ permanent residence cards, according to one of the new policies.

The application process can be shortened to two months from six months to receive the card. Spouses and children under 18-years-old can apply for the card at the same time.

Zhangjiang Lab represents big step for science hub ambition
By Zhang Ningning | 00:01 UTC+8 September 27, 2017 |

Print Edition

SHANGHAI’S ambition to be a global innovation and science hub took a giant stride yesterday with the unveiling of Zhangjiang Lab.

The lab, co-built by the city government and the Chinese Academy of Sciences, was unveiled in Pudong’s Zhangjiang Science City.

The lab will serve as a comprehensive national science center to promote basic science, officials said.

“In the beginning of the lab’s development, we will focus on building up major scientific facilities to make breakthroughs in fundamental sciences,” said Wang Xi, director of the lab, who is also the head of Shanghai Advanced Research Institute, which is part of the academy.

“Particularly on photonics (the physical science of light), life science, information technology and brain-inspired intelligence technologies, an interdisciplinary between life science and information technology,” Wang added.

Several national-level major science facilities in Zhangjiang will be integrated into the institute to make the lab better serve the science community.

Shanghai Synchrotron Radiation Facility is part of the set-up. This facility can create super beams hundreds of millions of times brighter than a normal X-ray.

Construction of a hard x-ray facility — an X-ray with high photon energy — will begin this year. The facility is expected to be China’s most expansive science infrastructure project.

Wang added the lab aims to attract top researchers from across the world. Officials have set a target to become a world-class national laboratory by 2030.

Shanghai Party Secretary Han Zheng, Bai Chunli, director of the academy, and the city’s Mayor Ying Yong attended the opening ceremony.

Last year, President Xi Jinping said China will facilitate the setting up of innovation platforms and national laboratories will play a leading role in those platforms.

Wan Gang, Minister of Science and Technology, said at a Pujiang Innovation Forum on Saturday that the country will further develop fundamental science and invest more in scientific infrastructures.

Space ambition

Also yesterday, an innovation and research institute for microsatellites of the academy was inaugurated in Zhangjiang.

Bai said the institute aims to be an innovation engine for satellite science and contribute to the country’s space ambition.

Ying said the institute represents a new phase in the development of Shanghai Engineering Centre for Microsatellites, which was co-built by the academy and the city government in 2003.

The city will continue to support the development and construction of the new institute, Ying added.

Over the past few years, the engineering center successfully developed 19 satellites, including a BeiDou navigation satellite, the world’s first quantum communication satellite, and China’s first observation satellite to monitor carbon dioxide level.

 

[JSCh]

Chinese company XDM 3D Printing Technology claims new XDM750 is world's largest SLM 3D printer
Sep 27, 2017 | By Benedict

XDM 3D Printing Technology, a 3D printing company based in Suzhou, China, claims to have developed the world’s largest selective laser melting (SLM) 3D printer. The XDM750 has a build volume of 750 x 750 x 500 mm, larger than Concept Laser’s X LINE 2000R.

It’s difficult to make conclusive statements about the world’s largest 3D printers. For one, you never know what private companies are doing in secret—just because a gigantic machine hasn’t been put on the market, that doesn’t mean it doesn’t exist.

But it’s also pretty hard to get objective reports about “record-breaking” machines from third parties. At present, there’s no Guinness World Records-type organization dedicated to 3D printing, so there’s nobody going round with a measuring tape and stopwatch verifying every claim by every company.

This isn’t such a problem with commercially available machines. In these cases, you simply have to check with the company’s customers to see if the machines are as big, fast, or efficient as they claim to be. (Or you can buy one yourself.) Besides, companies would get in a lot of trouble if their spec sheets didn’t match up to their products.

But with one-off 3D printers, brand-new printers, or machines not being sold at scale, you sometimes have to take a company’s word for it.

You might therefore take XDM 3D Printing Technology’s claim that it has developed the “world’s largest SLM 3D printer” with a pinch of salt.

That’s not because we think the company would put out a factually incorrect statement about printer dimensions. In that regard, the XDM750 is quite probably the world’s largest SLM printer. It’s just that we know so little about XDM 3D Printing Technology, we have no way of knowing whether the printer works at a high level.

Nonetheless, the XDM750 certainly sounds like a formidable machine in terms of size. With a build area of 750 x 750 x 500 mm, the SLM 3D printer can purportedly fabricate larger objects than would be possible with the Concept Laser X LINE 2000R, generally believed to be the largest laser melting machine on the market with a whopping 800 x 400 x 500 mm build area.

But eclipsing the X LINE 2000R in terms of size might not even be XDM’s boldest claim. Making a very large printer is one thing, but ensuring it meets the required quality standards is quite another. The Chinese 3D printer company claims to have done this too.

The Suzhou-based manufacturer says the performance of the XDM750 matches that of the most advanced metal 3D printers in the world, and could therefore be used in serious industries like aerospace, automotive, military, and medical.

It’s these claims that will take a little longer to evaluate. It’s possible that this could be the start of a serious wave of 3D printing evolution in the Far East; on the other hand, we might never hear about XDM again.

XDM was founded in 2015, and employs a number of technicians with long-term experience in SLM research. It already has 12 patents and three core technologies.



3ders.org - Chinese company XDM 3D Printing Technology claims new XDM750 is world's largest SLM 3D printer | 3D Printer News & 3D Printing News

 

[JSCh]

Synopsis: How to Make Superhydrophobicity Last
September 27, 2017

Researchers find tricks to prolong the typically short-lived water repellency of a superhydrophobic surface.

iStockphoto.com/Art Wager​

Coating a ship’s hull with a strongly water repellent material could lower the vessel’s drag in the water. A popular form of such a superhydrophobic material works because it has a rough surface that traps a lubricating cushion of air. But this type of material has yet to be utilized on ships, as the air layer tends to degrade with time. Researchers have now pinpointed certain conditions in the fluid that, if met, would lead to a more enduring air layer—though the conditions might be difficult to meet for ships.

The short-lived air layer is a well-known hurdle when it comes to using superhydrophobic materials for applications. For example, when a lotus leaf—the icon of superhydrophobicity—is submerged under 5 m of water, the air layer diffuses away in less than 2 min.

Huiling Duan and colleagues from Peking University, China, considered a superhydrophobic surface with a thermodynamic model that accounts for the diffusion of gas between the trapped air layer and the surrounding water. They found that an equilibrium state exists in which the total amount of air in the layer doesn’t change, provided there’s a sufficient quantity of gas dissolved in the water. Directly controlling the amount of dissolved gas in a body of water is tricky in the lab—let alone at sea. But the team’s experiments on lotus leaves and artificial superhydrophobic surfaces show that this control can be achieved indirectly in sealed systems by adjusting the pressure of the water acting on the surface. The team tested their idea on a lotus leaf, showing they could extend the air-layer lifetime to at least four hours—the maximum length of their experiments.

This research is published in Physical Review Letters.

–Katherine Wright

Katherine Wright is a Contributing Editor for Physics.


Physics - Synopsis: How to Make Superhydrophobicity Last

Yaolei Xiang, Shenglin Huang, Pengyu Lv, Yahui Xue, Qiang Su, and Huiling Duan. Ultimate Stable Underwater Superhydrophobic State. Phys. Rev. Lett. (2017). DOI: https://doi.org/10.1103/PhysRevLett.119.134501​

 

[JSCh]

China's high magnetic field facility passes testing
Source: Xinhua| 2017-09-27 22:13:59|Editor: An



HEFEI, Sept. 27 (Xinhua) -- China's Steady High Magnetic Field Facility (SHMFF) Wednesday passed testing by an expert panel organized by the National Development Reform Commission (NDRC).

The facility ranks second worldwide in terms of quantity and intensity.

The project, approved by NDRC in 2008, was jointly built by Hefei Institute of Physical Sciences of the Chinese Academy of Sciences (CASHIPS) and the University of Science and Technology of China.

As one only two 40-Tesla hybrid magnet groups worldwide, the SHMFF has the potential to reach an even higher level of 45 Tesla, according to Hans Schneider Muntau, a world-renowned high field magnet expert.

By creating a magnetic field as high as 40 Tesla, the SHMFF would become an experimental environment for fields such as high temperature superconductivity, quantum materials and life science.

Since 1913, 19 accomplishments closely linked to high magnetic fields have won Nobel Prizes.

Wang Yingjian, Party chief of CASHIPS, said the SHMFF has been used as an experimental environment for more than 100 universities and research institutions, including Tsinghua and Peking universities, since its trial operation began in 2010.

More than 800 of their accomplishments have been published in journals including Nature and Science.

China is the fifth country to have a high magnetic field facility, following the United States, where the other 40-Tesla hybrid magnet is located, France, the Netherlands and Japan.

Chinese scientists check the Steady High Magnetic Field Facility in a factory of Heifei, Anhui Province on September 27, 2017. (Image by Xinhua)

 

[JSCh]

Researchers Are First to Edit Human Embryos With Tiniest of Genetic Snips

Researchers from Sun Yat-sen University in China have for the first time used base editing, a technique that can tweak a single letter in a strand of DNA, to edit disease out of a human embryo. The team used the approach to fix a single mutation known to cause an inherited form of anemia. People with the disease have abnormally shaped blood cells.

The work was led by Junjiu Huang, who in 2015 headed up research showing that abnormal embryos from an IVF clinic with the same mutation could be fixed using CRISPR-Cas9 editing. But as we reported at the time, the results showed that CRISPR editing was inaccurate, and embryos often ended up with a mix of cells—some with corrected genomes, and some that still had the genetic fault.

Earlier this year, researchers used CRISPR to create the first gene-edited embryos in the U.S., and the results initially seemed promising. But closer examination of the work again suggested that the gene-editing technique still wasn't reliable enough to be used on an embryo that would be allowed to grow into a baby.

Huang's team has now moved on to a different editing technique, called simply base editing. It's exactly what it sounds like: instead of cutting out chunks of DNA, as CRISPR does, base editing alters just a single letter of DNA—in the case of the mutation that causes anemia, a faulty "G" is chemically changed to an "A." Crucially, the team's results, published in the journal Protein and Cell (paywall), minimized the kind of side effects that have plagued experiments with CRISPR. And, the researchers told the BBC, base editing could be effective on a range of disorders that are known to be caused by a single genetic error.

Posted by Michael Reilly
September 28th, 2017 11:11AM



Researchers Are First to Edit Human Embryos With Tiniest of Genetic Snips | MIT Technology Review

Puping Liang, Chenhui Ding, Hongwei Sun, Xiaowei Xie, Yanwen Xu, Xiya Zhang, Ying Sun, Yuanyan Xiong, Wenbin Ma, Yongxiang Liu, Yali Wang, Jianpei Fang, Dan Liu, Zhou Songyang, Canquan Zhou, Junjiu Huang. Correction of β-thalassemia mutant by base editor in human embryos. Protein & Cell (2017). DOI: 10.1007/s13238-017-0475-6​

 

[JSCh]

High-Efficiency and Full-Space Manipulation of Electromagnetic Wave Fronts with Metasurfaces
Tong Cai, GuangMing Wang, ShiWei Tang, HeXiu Xu, JingWen Duan, HuiJie Guo, FuXin Guan, ShuLin Sun, Qiong He, and Lei Zhou
Phys. Rev. Applied 8, 034033 – Published 28 September 2017

Abstract

Metasurfaces offer great opportunities to control electromagnetic (EM) waves, but currently most metadevices work either in pure reflection or pure transmission mode, leaving half of the EM space completely unexplored. Here, we propose an alternative type of metasurface, composed of specifically designed meta-atoms with polarization-dependent transmission and reflection properties, to efficiently manipulate EM waves in the full space. As a proof of concept, three microwave metadevices are designed, fabricated, and experimentally characterized. The first two metadevices can bend or focus EM waves at different sides (i.e., transmission and reflection sides) of the metasurfaces, depending on the incident polarization, while the third one changes from a wave bender for the reflected wave to a focusing lens for the transmitted wave as the excitation polarization is rotated, with all of these functionalities exhibiting very high efficiencies (in the range of 85%–91%) and total thickness ∼λ/8. Our findings significantly expand the capabilities of metasurfaces in controlling EM waves, and can stimulate high-performance multifunctional metadevices facing more challenging and diversified application demands.
​

DOI:https://doi.org/10.1103/PhysRevApplied.8.034033

© 2017 American Physical Society


Phys. Rev. Applied 8, 034033 (2017) - High-Efficiency and Full-Space Manipulation of Electromagnetic Wave Fronts with Metasurfaces

 

[JSCh]

Chinese scientists reveal why Zika virus causes microcephaly
Source: Xinhua| 2017-09-29 03:19:03|Editor: yan



WASHINGTON, Sept. 28 (Xinhua) -- Chinese researchers said Thursday they might have solved the mystery of why the Zika virus causes microcephaly, a birth defect marked by small head size that can lead to severe developmental problems in babies.

In a study published in the U.S. journal Science, a team led by Cheng-Feng Qin of the Beijing Institute of Microbiology and Epidemiology reported that one single genetic change, likely acquired in 2013, gave the mosquito-borne virus the ability to cause severe fetal microcephaly.

"Our findings offer a reasonable explanation for the unexpected causal link of Zika to microcephaly, and will help understand how Zika evolved from an innocuous mosquito-borne virus into a congenital pathogen with global impact," Qin said.

Zika was first identified in 1947 in Uganda, and until its recent emergence in the Americas, was a little known one that sporadically causes mild infections.

Then, it rapidly swept through South and Central America in 2015, and due to its link to congenital brain abnormalities, especially microcephaly during pregnancy, the World Health Organization declared in early 2016 the current epidemics a public health emergency of international concern.

However, scientists remain unable to determine why the virus evolved into a pathogen triggering severe neurological syndromes.

By comparing contemporary Zika virus strains from the 2015 and 2016 South American epidemics with an ancestral Cambodian virus that was circulating in 2010, Qin and colleagues found one critical mutation that conferred the ability to cause microcephaly in mouse models of fetal infection.

That one change, S139N, which replaced a serine amino acid with an asparagine at the 139th position of a Zika protein called prM, also made the virus more lethal to human neuron precursor cells in culture compared with the ancestral form.

Zika accumulated numerous changes throughout its genome between 2010 and 2016, of which S139N caused substantially more severe microcephaly and embryonic lethality in mouse models.

Evolutionary analyses revealed that the S139N change likely arose sometime around 2013, which coincided with initial reports of microcephaly.

It was then stably maintained during subsequent spread to the America.

"The discovery should provide guidance for the study of pathogenetic mechanisms of the Zika virus and for the development of vaccines and treatments," Qin said.

Ling Yuan, Xing-Yao Huang, Zhong-Yu Liu, Feng Zhang, Xing-Liang Zhu, Jiu-Yang Yu, Xue Ji, Yan-Peng Xu, Guanghui Li, Cui Li, Hong-Jiang Wang, Yong-Qiang Deng, Menghua Wu, Meng-Li Cheng, Qing Ye, Dong-Yang Xie, Xiao-Feng Li, Xiangxi Wang, Weifeng Shi, Baoyang Hu, Pei-Yong Shi, Zhiheng Xu, Cheng-Feng Qin. A single mutation in the prM protein of Zika virus contributes to fetal microcephaly. Science (2017). DOI: 10.1126/science.aam7120​

 

[JSCh]

China starts construction of major national scientific infrastructure
By Gao Yun
2017-09-29 15:41 GMT+8

‍
China started building an integrated experimental device for extreme conditions in Beijing on Thursday, according to local media reports. Once completed, it can greatly improve the country’s scientific competitiveness in relevant industries.

It is the first major scientific and technological infrastructure project to be constructed at the Huairou Science City, a comprehensive national science center in Beijing's Huairou district.

Primarily operated by the Institute of Physics of the Chinese Academy of Sciences (CAS), it is a large scientific experimental device that incorporates a group of facilities which generate extreme conditions such as ultralow temperatures, ultrahigh pressure, high magnetic fields and ultrafast optical fields, as well as systems for sample representation, measurement and other supporting functions.

The rendering of the device in Huairou Science City, Beijing /CAS Photo

Extreme conditions

Substances are formed under certain physical conditions and, under the extreme conditions generated by these physical experiments, new substances and new states of matter that cannot exist under normal conditions will form, leading to new scientific phenomena and breakthroughs.

For example, the ultralow temperature is 300,000 times lower than room temperature, and the high magnetic field 600,000 times stronger than the Earth’s. The ultrahigh pressure may be equivalent to that of the Earth’s core.

Make a big significance

Making breakthroughs under extreme experimental conditions has become an important scientific model and many developed countries have invested heavily in this field, equipping their research institutions with advanced experimental facilities designed specifically for extreme conditions.

"The overall level of experimental methods under extreme conditions will directly improve China’s competitiveness in several core domains," said Fang Zhong, director of the Institute of Physics, CAS.

Fang Zhong, director of the Institute of Physics, CAS /CAS Photo

The device is of significant value in scientific research, Fang said. It can be used in the research of non-conventional superconductors, the topological state of matter and new quantum materials and devices, and also help accelerate the ultrafast science research in physics, chemistry, biomedicine.

Integration and penetration into different scientific disciplines will be promoted.

The project is expected to be completed in five years, and once completed, will be the world’s first consumer device that incorporates extreme conditions.

Both domestic and international users will have access to the device, according to Lyu Li, the project’s chief scientist.

 

[JSCh]

China Builds World's First Space-ground Integrated Quantum Communication Network
Sep 29, 2017

Using Micius for a quantum-safe intercontinental video conference between China and Austria.

The first quantum-safe video conference was held between President BAI Chunli of the Chinese Academy of Sciences in Beijing and President Anton Zeilinger of the Austria Academy of Sciences in Vienna, as the first real-world demonstration of intercontinental quantum communication on September 29th.

Message sending from Vienna to Beijing through space-ground integrated quantum network. (Image by PAN Jianwei's team)

Private and secure communications are fundamental human needs. In particular, with the exponential growth of Internet use and e-commerce, it is of paramount importance to establish a secure network with global protection of data. Traditional public key cryptography usually relies on the perceived computational intractability of certain mathematical functions. In contrast, quantum key distribution (QKD) uses individual light quanta (single photon) in quantum superposition states to guarantee unconditional security between distant parties. Previously, the quantum communication distance had been limited to a few hundred kilometers, due to the channel loss of fibers or terrestrial free space. A promising solution to this problem is exploiting satellite and space-based link, which can conveniently connect two remote points on the Earth with greatly reduced channel loss because most of the photons' propagation path is in empty space with negligible loss and decoherence.

Illustration of the experimental set-up. (Image by PAN Jianwei's team)

A cross-disciplinary multi-institutional team of scientists from the Chinese Academy of Sciences, led by Professor PAN Jianwei, has spent more than ten years in developing a sophisticated satellite, named Micius, dedicated for quantum science experiments (for the project timeline, see Appendix), which was successfully launched on 16th August 2016, from Jiuquan, China, orbiting at an altitude of ~500 km . The satellite is equipped with three payloads: a decoy-state QKD transmitter, an entangled-photon source, and a quantum teleportation receiver and analyzer. Five ground stations are built in China to cooperate with the Micius satellite, located in Xinglong (near Beijing, 40°23'45.12''N, 117°34'38.85''E, altitude 890m), Nanshan (near Urumqi, 43°28'31.66''N, 87°10'36.07''E, altitude 2028m), Delingha (37°22'44.43''N, 97°43'37.01"E, altitude 3153m), Lijiang (26°41'38.15''N, 100°1'45.55''E, altitude 3233m), and Ngari in Tibet (32°19'30.07''N, 80°1'34.18''E, altitude 5047m).

Within a year after the launch, three key milestones that will be central to a global-scale quantum internet have been achieved: satellite-to-ground decoy-state QKD with kHz rate over a distance of ~1200 km (Liao et al. 2017, Nature 549, 43); satellite-based entanglement distribution to two locations on the Earth separated by ~1200 km and Bell test (YIN et al. 2017, Science 356, 1140), and ground-to-satellite quantum teleportation (REN et al. 2017, Nature 549, 70). The effective link efficiencies in the satellite-based QKD were measured to be ~20 orders of magnitudes larger than direct transmission through optical fibers at the same length at 1200 km.

The satellite-based QKD has now been combined with metropolitan quantum networks, in which fibers are used to efficiently and conveniently to connect many users inside a city with a distance scale of ~100 km. For example, the Xinglong station has now been connected to the metropolitan multi-node quantum network in Beijing via optical fibers. Very recently, the largest fiber-based quantum communication backbone has been built in China by Professor PAN's team, linking Beijing to Shanghai (going through Jinan and Hefei, and 32 trustful relays) with a fiber length of 2000 km. The backbone uses decoy-state protocol QKD and achieves an all-pass secure key rate of 20 kbps. It is on trial for real-world applications by government, banks, securities and insurance companies.

Establishment of a reliable space-to-ground link for quantum state transfer. (Image by PAN Jianwei's team)

The Micius satellite can be further exploited as a trustful relay to conveniently connect any two points on the earth for high-security key exchange. Early this year, the Chinese team has implemented satellite-to-ground QKD in Xinglong. After that, the secure keys were stored in the satellite for 2 hours until it reached Nanshan station near Urumqi, by a distance of ~2500 km from Beijing. By performing another QKD between the satellite and Nanshan station, and using one-time-pad encoding, secure key between Xinglong and Nanshan were then established. To test the robustness and versatility of the Micius, QKD from the satellite to Graz ground station near Vienna has also been carried out successfully this June, as a collaboration between Professor PAN and Professor Anton Zeilinger's group. Upon request, future similar experiments are also planned between China and Singapore, Italy, Germany, and Russia.

Performance of satellite-to-ground QKD performance during one orbit. (Image by PAN Jianwei's team)



China Builds World's First Space-ground Integrated Quantum Communication Network---Chinese Academy of Sciences

 

[JSCh]

Researchers Are First to Edit Human Embryos With Tiniest of Genetic Snips

Researchers from Sun Yat-sen University in China have for the first time used base editing, a technique that can tweak a single letter in a strand of DNA, to edit disease out of a human embryo. The team used the approach to fix a single mutation known to cause an inherited form of anemia. People with the disease have abnormally shaped blood cells.

The work was led by Junjiu Huang, who in 2015 headed up research showing that abnormal embryos from an IVF clinic with the same mutation could be fixed using CRISPR-Cas9 editing. But as we reported at the time, the results showed that CRISPR editing was inaccurate, and embryos often ended up with a mix of cells—some with corrected genomes, and some that still had the genetic fault.

Earlier this year, researchers used CRISPR to create the first gene-edited embryos in the U.S., and the results initially seemed promising. But closer examination of the work again suggested that the gene-editing technique still wasn't reliable enough to be used on an embryo that would be allowed to grow into a baby.

Huang's team has now moved on to a different editing technique, called simply base editing. It's exactly what it sounds like: instead of cutting out chunks of DNA, as CRISPR does, base editing alters just a single letter of DNA—in the case of the mutation that causes anemia, a faulty "G" is chemically changed to an "A." Crucially, the team's results, published in the journal Protein and Cell (paywall), minimized the kind of side effects that have plagued experiments with CRISPR. And, the researchers told the BBC, base editing could be effective on a range of disorders that are known to be caused by a single genetic error.

Posted by Michael Reilly
September 28th, 2017 11:11AM



Researchers Are First to Edit Human Embryos With Tiniest of Genetic Snips | MIT Technology Review

Puping Liang, Chenhui Ding, Hongwei Sun, Xiaowei Xie, Yanwen Xu, Xiya Zhang, Ying Sun, Yuanyan Xiong, Wenbin Ma, Yongxiang Liu, Yali Wang, Jianpei Fang, Dan Liu, Zhou Songyang, Canquan Zhou, Junjiu Huang. Correction of β-thalassemia mutant by base editor in human embryos. Protein & Cell (2017). DOI: 10.1007/s13238-017-0475-6​

Chinese scientists fix genetic disorder in cloned human embryos
A method for precisely editing genes in human embryos hints at a cure for a blood disease.

• David Cyranoski
• 02 October 2017

Fixing the genetic mutation linked to β-thalassaemia would save affected individuals from having to get life-sustaining blood transfusions.

A team in China has taken a new approach to fixing disease genes in human embryos. The researchers created cloned embryos with a genetic mutation for a potentially fatal blood disorder, and then precisely corrected the DNA to show how the condition might be prevented at the earliest stages of development.

The report, published on 23 September in Protein & Cell, is the latest in a series of experiments to edit genes in human embryos. And it employs an impressive series of innovations, scientists say. Rather than replacing entire sections of genes, the team, led by Junjiu Huang at Sun Yat-sen University in Guangzhou, China, tweaked individual DNA letters, or bases, using a precision gene-editing technology developed in the United States.

Huang’s team is also the first to edit out the mutation responsible for a ‘recessive’ disease: one caused by having two faulty copies of a gene. Because it would be difficult for researchers to find dozens of embryos that all have this rare double mutation, the team worked around this roadblock by developing embryonic clones from their patient’s skin cells.

“I thought, ‘Why would they do cloning?’ Then I read the paper, and thought, ‘Wow, that’s fascinating,’” says Shoukhrat Mitalipov, a reproductive-biology specialist at the Oregon Health and Science University in Portland who pioneered human cloning and also works on gene editing in embryos. “I would not have thought to do this.”

Scientists around the world have now published eight studies reporting gene editing in human embryos, five in the past two months. None have permitted the embryos to grow beyond 14 days, and the research has had different purposes: some to test gene-editing technologies; others to edit various disease-related genes; and some to unravel the mechanisms behind early embryonic development. Huang’s team led the first report, published in April 2015, in which they used the CRISPR–Cas9 enzyme complex to snip chromosomes at specific locations, excise DNA and replace it with other genetic material.

Precision editing
In the latest study, Huang’s team used ‘base editing’, a modification of CRISPR–Cas9. It guides an enzyme to specific gene sequences, but does not cut the DNA. Instead, the Cas9 enzyme is disabled and tethered to another enzyme that can swap out individual DNA base pairs. So far, this technique can convert guanine (‘G’) to adenine (‘A’), and cytosine (‘C’) to thymine (‘T’). Hundreds of genetic diseases are caused by single-base changes, or ‘point mutations’, and so editing of this sort at the embryonic stage could potentially stave off such conditions.

Huang’s team chose one mutation common in the Chinese population: a switch from an A to a G at a certain spot in the HBB gene, which can lead to β-thalassaemia, a recessive blood disorder associated with severe or fatal anaemia. Researchers generally source embryos from in vitro fertilization (IVF) clinics, but it’s rare for these facilities to have embryos with two copies of the same rare mutation. So Huang’s team found a person with the blood disorder, extracted their skin cells and used cloning techniques to develop embryos with the same genetic makeup.

The researchers reported that in 8 of 20 cloned embryos, they were able to convert the errant G back into an A in one or both copies of the gene. (Repairing only one copy might be enough to cure a recessive disease.) That rate is too low for the technique to be considered for clinical use, but the efficiency was high relative to that achieved in other gene-editing studies. “The repair rate is pretty good, and certainly promising,” says Gaetan Burgio, a geneticist at the Australian National University in Canberra. “Our study opens new avenues for therapy of β-thalassaemia and other inherited diseases,” says Huang.

But scientists caution that not all cells in the eight embryos were fixed. Such embryos are ‘mosaic’, meaning that they have a patchwork of cells with different genetic make-ups, which is potentially dangerous. “It looks like solid work, but highlights that the problem of mosaicism remains a challenge for any form of gene editing in the human embryo,” says Dieter Egli, a stem-cell biologist at Columbia University in New York City.

Unintended consequences
Some scientists also question whether Huang’s team looked thoroughly enough for unintended genetic changes, called off-target effects, that might have been caused by the base-editing procedure, although the authors reported that none were found.

Huang says future experiments will be more comprehensive, but that this first study was a successful proof of principle that the base-editing technique can be used to correct a disease mutation in a human embryo. It may be that conventional CRISPR–Cas9 cannot fix embryos when both copies are faulty, although this isn’t yet clear. In August, for instance, Mitalipov’s team reported using CRISPR–Cas9 to repair a mutation in a gene that can cause a potentially deadly heart disorder, by using the other, healthy copy of the gene as a template.

In the future, Huang says, he plans to ask for oocytes and sperm from donors who have one mutated copy of the gene — and so are unaffected by the condition, but are carriers of the disease — and use these to produce embryos. Some of those embryos would have two mutated copies, and some one, but Huang wants to edit both types. That raises the contentious idea that gene editing might be used not only to prevent severe disease, but also to eliminate the chance of people becoming carriers of the disorder. “Base editing can repair the mutant site and block it from being passed on to the next generation,” he says.

Nature doi:10.1038/nature.2017.22694



Chinese scientists fix genetic disorder in cloned human embryos : Nature News & Comment

 

[JSCh]

Chinese scientists make breakthrough in replacing WiFi with LiFi
(Xinhua) 14:13, October 03, 2017

CHANGCHUN, Oct. 3 (Xinhua) -- Chinese scientists have made a breakthrough in creating full-color emissive carbon dots (F-CDs), which brings them one step closer to developing a faster wireless communication channel that could be available in just six years.

Light Fidelity, known as LiFi, uses visible light from LED bulbs to transfer data much faster than radio wave-based WiFi.

While most current research uses rare earth materials to provide the light for LiFi to transmit data, a team of Chinese scientists have created an alternative -- F-CDs, a fluorescent carbon nanomaterial that proves to be safer and faster.

"Many researchers around the world are still working on this. We were the first to successfully create it using cost-effective raw materials such as urea with simple processing," said Qu Songnan, an associate researcher at Changchun Institute of Optics, Fine Mechanics and Physics, the Chinese Academy of Sciences, which leads the research.

Qu said rare earth has a long lifespan which reduces the speed of LiFi transmission. However, F-CDs enjoy the advantage of faster data transmission speeds.

In previous studies, carbon dots were limited to the emission of lights such as blue and green. The new nanomaterial that Qu's team has developed can emit all light visible to the human eye, which is a breakthrough in the field of fluorescent carbon nanomaterial.

Qu said this is significant for the development of LiFi, which he expects to enter the market in just six years.

A 2015 test by a Chinese government ministry showed that LiFi can reach speeds of 50 gigabytes per second, at which a movie download can be completed in just 0.3 seconds.

 

[JSCh]

Public Release: 3-Oct-2017
Astronomers reveal evidence of dynamical dark energy
University of Portsmouth

The cosmological "constant" (illustrated by the straight yellow line) is introduced to explain the accelerated expansion of the Universe (shown as the expanding blue cone) due to the presence of dark energy. The study instead suggests that the contribution of dark energy to this expansion is time-dependent (grey curve). The uncertainty of this time dependency is also shown (blue shaded area).
Credit: Gong-Bo Zhao, NAOC and the University of Portsmouth.

An international research team, including astronomers from the University of Portsmouth, has revealed evidence of dynamical dark energy.

The discovery, recently published in the journal Nature Astronomy, found that the nature of dark energy may not be the cosmological constant introduced by Albert Einstein 100 years ago, which is crucial for the study of dark energy.

Lead author of the study Professor Gong-Bo Zhao, from the Institute of Cosmology and Gravitation (ICG) at the University of Portsmouth and the National Astronomical Observatories of China (NAOC), said: "We are excited to see that current observations are able to probe the dynamics of dark energy at this level, and we hope that future observations will confirm what we see today."

Co-author Professor Bob Nichol, Director of the ICG, said: "Since its discovery at the end of last century, dark energy has been a riddle wrapped in an enigma. We are all desperate to gain some greater insight into its characteristics and origin. Such work helps us make progress in solving this 21st Century mystery."

Revealing the nature of dark energy is one of key goals of modern sciences. The physical property of dark energy is represented by its Equation of State (EoS), which is the ratio of pressure and energy density of dark energy.

In the traditional Lambda-Cold Dark Matter (LCDM) model, dark energy is essentially the cosmological constant, i.e., the vacuum energy, with a constant EoS of -1. In this model, dark energy has no dynamical features.

In 2016, a team within the SDSS-III (BOSS) collaboration led by Professor Zhao performed a successful measurement of the Baryonic Acoustic Oscillations (BAO) at multiple cosmic epochs with a high precision.

Based on this measurement and a method developed by Professor Zhao for dark energy studies, the team found an evidence of dynamical dark energy at a significance level of 3.5 sigma. This suggests that the nature of dark energy may not be the vacuum energy, but some kind of dynamical field, especially for the quintom model of dark energy whose EoS varies with time and crosses the -1 boundary during evolution, according to NAOC.

The dynamics of dark energy needs to be confirmed by next-generation astronomical surveys. The team points to the upcoming Dark Energy Spectroscopic Instrument (DESI) survey, which aims to begin creating a 3D cosmic map in 2018.

In the next five to ten years, the world largest galaxy surveys will provide observables which may be key to unveil the mystery of dark energy.

The new study was supported by the National Natural Science Foundation of China (NSFC), Chinese Academy of Sciences and a Royal Society Newton Advanced Fellowship.

Professor Nichol added: "This work is the culmination of many years of work in collaboration between scientists in China and the UK. Gong-Bo is one of our brightest stars holding a joint position between NAOC and here at the ICG."


Astronomers reveal evidence of dynamical dark energy | EurekAlert! Science News

Gong-Bo Zhao, Marco Raveri, Levon Pogosian, Yuting Wang, Robert G. Crittenden, Will J. Handley, Will J. Percival, Florian Beutler, Jonathan Brinkmann, Chia-Hsun Chuang, Antonio J. Cuesta, Daniel J. Eisenstein, Francisco-Shu Kitaura, Kazuya Koyama, Benjamin L’Huillier, Robert C. Nichol, Matthew M. Pieri, Sergio Rodriguez-Torres, Ashley J. Ross, Graziano Rossi, Ariel G. Sánchez, Arman Shafieloo, Jeremy L. Tinker, Rita Tojeiro, Jose A. Vazquez & Hanyu Zhang. Dynamical dark energy in light of the latest observations. Nature Astronomy (2017). DOI:10.1038/s41550-017-0216-z​

 

[JSCh]

A new way to improve solar cells can also benefit self-driving cars
By figuring out how to help solar cells capture more photons, a team of engineers unexpectedly improved the collision-avoidance systems of autonomous cars.

October 02, 2017 By Shara Tonn

When a team of engineers went to work in 2015 looking for a new technique to boost the cost-effectiveness of solar cells, they didn’t realize they’d end with a bonus – a way to help improve the collision avoidance systems of self-driving cars.

But that’s precisely what happened, as the engineers, James Harris and graduate student Kai Zang, explain in a recent Nature Communications article.

The twin discoveries started, they say, when they began looking for a solution to a well-known problem in the world of solar cells. Solar cells capture photons from sunlight in order to convert them into electricity. The thicker the layer of silicon in the cell, the more light it can absorb, and the more electricity it can ultimately produce. But the sheer expense of silicon has become a barrier to solar cost-effectiveness.

So the Stanford engineers figured out how to create a very thin layer of silicon that could absorb as many photons as a much thicker layer of the costly material. Specifically, rather than laying the silicon flat, they nanotextured the surface of the silicon in a way that created more opportunities for light particles to be absorbed. Their technique increased photon absorption rates for the nanotextured solar cells compared to traditional thin silicon cells, making more cost-effective use of the material.

Then came the surprise. After the researchers shared these efficiency figures, engineers working on autonomous vehicles began asking whether this texturing technique could help them get more accurate results from a collision-avoidance technology called LIDAR, which is conceptually like sonar except that it uses light rather than sound waves to detect objects in the car’s travel path.

LIDAR works by sending out laser pulses and calculating the time it takes for the photons to bounce back. The autonomous car engineers understood that current photon detectors use thick layers of silicon to make sure they capture enough photons to accurately map the terrain ahead. They wondered if texturing a thin layer of silicon, much like on the solar cells, would lead to more accurate maps than the current thin silicon.

Indeed, in their new paper, the Stanford engineers report that their textured silicon can capture as many as three to six times more of the returning photons than today’s LIDAR receivers. They believe this will enable self-driving car engineers to design high-performance, next-generation LIDAR systems that would continuously send out a single laser pulse in all directions. The reflected photons would be captured by an array of textured silicon detectors, creating moment-to-moment maps of pedestrian-filled city crosswalks.

Harris said the texturing technology could also help to solve two other LIDAR snags unique to self-driving cars – potential distortions caused by heat and the machine equivalent of peripheral vision.

The heat problem occurs because the LIDAR laser apparatus can heat up during extended use, causing photon wavelengths to shift slightly. Such shifts could cause light particles to bounce off traditional silicon that is made to absorb specific wavelengths. But the Stanford nanotexturing technology can absorb photons across a broad spectrum, eliminating this heat-shift issue.

With respect to the machine equivalent of peripheral vision, Harris and Zang believe it may be possible to make a flexible version of their nanotextured silicon receptor. Flexibility would allow them to curve the receptor. Between that and the light-trapping advantage of their nanotextured surface, they think it may be possible for LIDAR systems to enlarge the angle of acceptance for photons, in order to more completely identify all potential obstacles.

Harris said he always thought Zang’s texturing technique was a good way to improve solar cells. “But the huge ramp up in autonomous vehicles and LIDAR suddenly made this 100 times more important,” he says.



A new way to improve solar cells can also benefit self-driving cars | School of Engineering | Stanford