China Science & Technology Forum

[TaiShang]

208-meter-high elevator holds three world records
November 19, 2015

An outdoor elevator installed on a mountain has received three world record certifications by the World Record Association (WRA) in one day, reported chinanews.com on Wednesday.

The elevator is 208 meters in height and entirely outdoors. [Photo/Chinanews.com]

The elevator has become a must-ride when visiting Taihang Mountain in Shanxi province since it opened in October.

It can take a maximum of 21 people for one trip that takes about 52 seconds. While riding the elevator, people can enjoy a thrilling panoramic view of Taihang Mountain, one of the ten most beautiful valleys in China.

On November 17, it became certified as the world's tallest outdoor sightseeing elevator, the world's fastest outdoor multi-level sightseeing elevator on a cliff, and the world's highest multi-level transparent sightseeing platform on a cliff.

 

[JSCh]

Smart supercapacitor fiber with shape memory
November 20, 2015

Wearing your mobile phone display on your jacket sleeve or an EKG probe in your sports kit are not off in some distant imagined future. Wearable "electronic textiles" are on the way. In the journal Angewandte Chemie, Chinese researchers have now introduced a new type of fiber-shaped supercapacitor for energy-storage textiles. Thanks to their shape memory, these textiles could potentially adapt to different body types: shapes formed by stretching and bending remain "frozen", but can be returned to their original form or reshaped as desired.

Any electronic components designed to be integrated into textiles must be stretchable and bendable. This is also true of the supercapacitors that are frequently used for data preservation in static storage systems (SRAM). SRAM is a type of storage that holds a small amount of data that is rapidly retrievable. It is often used for caches in processors or local storage on chips in devices whose data must be stored for long periods without a constant power supply. Some time ago, a team headed by Huisheng Peng at Fudan University developed stretchable, pliable fiber-shaped supercapacitors for integration into electronic textiles. Peng and his co-workers have now made further progress: supercapacitor fibers with shape memory.

The fibers are made using a core of polyurethane fiber with shape memory. This fiber is wrapped with a thin layer of parallel carbon nanotubes like a sheet of paper. This is followed by a coating of electrolyte gel, a second sheet of carbon nanotubes, and a final layer of electrolyte gel. The two layers of carbon nanotubes act as electrodes for the supercapacitor. Above a certain temperature, the fibers produced in this process can be bent as desired and stretched to twice their original length. The new shape can be "frozen" by cooling. Reheating allows the fibers to return to their original shape and size, after which they can be reshaped again. The electrochemical performance is fully maintained through all shape changes.

Weaving the fibers into tissues results in "smart" textiles that could be tailored to fit the bodies of different people. This could be used to make precisely fitted but reusable electronic monitoring systems for patients in hospitals, for example. The perfect fit should render them both more comfortable and more reliable.

More information: Jue Deng et al. A Shape-Memory Supercapacitor Fiber, Angewandte Chemie International Edition (2015). DOI: 10.1002/anie.201508293

Smart supercapacitor fiber with shape memory

 

[Martian2]

China’s Long March 3B rocket successfully launches first Laotian satellite - SpaceFlight Insider

 

[Martian2]

Coal-to-chemicals grows in China, technology exports considered | Plastics News

"The Chinese have successfully converted coal to olefins at a cost of $20 to $25 per ton at facilities in remote coal-rich regions."

 

[zeronet]

Coal-to-chemicals grows in China, technology exports considered | Plastics News

"The Chinese have successfully converted coal to olefins at a cost of $20 to $25 per ton at facilities in remote coal-rich regions."

if similar cost can be achieved to coal's liquid conversion, $20~25 per ton meaning $3~4 per barrel for conversion cost. , the total cost of converted liquid could be controlled under $10/barrel for produced crude oil, almost as cheap as Saudi's average $7/barrel, much cheaper than American's shale oil. That's a great news for all coal-rich countries in the world. The major problem is the environmental affect, if it is no worse than shale oil production, then that's very acceptable. Geez, the middle east oil rich countries will be on grill with so many new technologies such as shale oil, coal oil, and green energies suddenly coming out of nowhere.

 

[Beast]

$20~25 per ton meaning $3~4 per barrel for conversion cost, the total cost could be controlled under $10/barrel for produced crude oil, almost as cheap as Saudi's average $7/barrel, much cheaper than American's shale oil. That's a great news for all coal-rich countries in the world. The major problem is the environmental affect, if it is no worse than shale oil production, then that's very acceptable. Geez, the middle east oil rich countries will be on grill with so many new technologies such as shale oil, coal oil, and green energies suddenly coming out of nowhere.

The era of fossil fuel is almost certainly coming to an end.

 

[JSCh]

Solid electrolyte interphases on lithium metal anode
November 23, 2015

​

The prestigious Advanced Science journal has just published a review paper on solid electrolyte interphases of lithium metal anodes contributed by Prof. Qiang Zhang in Tsinghua University, China and Ji-Guang Zhang in Pacific Northwest National Laboratory.

"Lithium (Li) metal is regarded as the 'Holy Grail' of rechargeable battery technologies due to the high theoretical specific capacity, 3860 mA h g-1, 10 times that of commercial graphite anode, and the lowest redox potential, -3.040 V vs. the standard hydrogen electrode. Therefore, lithium metal batteries, such as lithium-sulfur and lithium-oxygen batteries with the theoretical energy density of 2600 and 3400 Wh kg-1, could be promising candidates in next-generation energy storage devices," said Dr. Qiang Zhang, an associate professor at Department of Chemical Engineering, Tsinghua University, Beijing, China.

"However, the safe use of lithium metal as an anode is still a great challenge, for the dendritic and mossy metal deposits are very easily obtained on working lithium metal anode. Lithium dendrites induce a low Coulombic efficiency and severe safety risk, hindering the practical demonstration of high-energy-density lithium metal batteries. The dendrite nucleation and growth are closely related to the surface layer between the electrolyte and anode, called the solid electrolyte interphase (SEI). The surface component and structure of the SEI layer play an extremely important effect on the morphology of lithium deposits and decide the cycling performance of lithium metal anode. Consequently, it is of great importance to have a deep understanding on the SEI layer."

"The recent achievements on the SEI layer of the lithium metal anode are highlighted in my manuscript," said Xin-Bing Cheng, a graduate student and the first author of the review, "We have briefly summarized the mechanisms of SEI formation and models of SEI structure. The analysis methods to probe the surface chemistry, surface morphology, electrochemical property, dynamic characteristics of the SEI layer are emphasized. The critical factors affecting the SEI formation, such as electrolyte component, temperature, current density, are comprehensively debated. The paper summarizes efficient methods to modify the SEI layer with the introduction of a new electrolyte system and additives, ex-situ formed protective layer, and electrode design."

Although these works afford new insights into SEI research, a robust and precise route for SEI modification with a well-designed structure, as well as the relationship between structure, properties, and electrochemical performance, is still inadequate. More studies on SEI layer building require collaborative works from physics, chemistry, nanomaterials, and engineering communities.

"Through further investigation on the science and engineering of SEI on lithium metal, the use of lithium metal as a superior anode in a rechargeable cell is quite promising. The ultra-stable and robust SEI will enable broad applications of rechargeable Li metal in advanced Li–S batteries, Li–air batteries, and other advanced Li batteries," Qiang told Phys.org.

More information: Xin-Bing Cheng et al. A Review of Solid Electrolyte Interphases on Lithium Metal Anode, Advanced Science (2015). DOI: 10.1002/advs.201500213

Provided by: Tsinghua University

Solid electrolyte interphases on lithium metal anode

 

[Martian2]

Taiwanese researchers use nanoparticles to produce algae biodiesel : Biofuels Digest

"The new method can extract 97.1 percent of the fats for conversion into biodiesel compared to less than 60 percent using existing technology."

 

[JSCh]

Spotlight on Optics
Highlighted Articles from OSA Journals

October 2015

Spotlight Summary by Taek Yong Hwang
High-energy large-aperture Ti:sapphire amplifier for 5 PW laser pulses

Ultrafast lasers have contributed to expanding continuously our understanding of light-matter interactions with an increase in their peak power. Historically, to generate ultrafast laser pulses with a higher peak power, laser scientists put great efforts on amplifying the energy of pulse without creating any nonlinear effects or damages in the amplifier, while keeping the final output pulse duration nearly the same as that before amplification. These efforts eventually led to the invention of chirped pulse amplification (CPA) technique in 1985, significantly elevating the achievable peak power of ultrafast laser pulses by stretching out the seed pulse prior to amplification and then compressing the amplified pulse into nearly original seed pulse duration. Currently, the CPA technique is used even in a state of the art petawatt level femtosecond laser system by employing a series of amplifiers.

To further boost the peak power of the output laser pulse without adding additional amplifiers, a larger aperture Ti:sapphire crystal can be used in the amplifiers. However, using a larger aperture crystal will significantly increase the chance of inducing transverse amplified spontaneous emission (TASE) and parasitic lasing (PL), and the suppression of these two are essential to avoid deteriorating the efficiency of amplification. In this Optics Letters article, Yuxi Chu et al. use two traditional techniques, a matched index cladding and transverse gain control techniques, in the multipass (4 passes) amplifiers pumped with two high-energy pulses (527 nm), and search for optimal conditions to suppress TASE and PL effectively. First, the authors apply absorber-doped index-matching oil as the cladding of the Ti:sapphire crystal. This index-matching oil highly increases the transmittance at the crystal-oil interface by reducing the difference in index of refraction at the interface, and the absorber in the oil absorbs the transmitted emission from the crystal. This eventually results in reducing TASE and PL by enhancing the loss of emission. Next, the control of transverse gain in the crystal is used for further optimization by adjusting the pump-seed time delay during 4 passes of amplification. At each seed-pulse energy, the authors also show that the delay needs to be re-optimized, since the injected seed pulse affects the transverse gain. With these two optimization processes, considering a loss of 28% at the pulse compressor, the authors for the first time demonstrate an output pulse energy of 138.5 J at the maximum peak power of 5.13 PW with the Ti:sapphire laser system.

In summary, the authors successfully describe how to implement a large-aperture Ti:sapphire crystal in a petawatt laser system, and how to generate hundred-joule level pulses by effectively suppressing the TASE and PL through the optimization of the matched index cladding and transverse gain control techniques. As the authors note, the peak power of ultrafast laser pulses can potentially be increased further with these optimization techniques, because a larger aperture of Ti:sapphire crystal can be easily employed.



Article Reference

High-energy large-aperture Ti:sapphire amplifier for 5 PW laser pulses
Yuxi Chu, Zebiao Gan, Xiaoyan Liang, Lianghong Yu, Xiaoming Lu, Cheng Wang, Xinliang Wang, Lu Xu, Haihe Lu, Dingjun Yin, Yuxin Leng, Ruxin Li, and Zhizhan Xu
Opt. Lett. 40(21) 5011-5014 (2015) View: Abstract | HTML | PDF

OSA | Spotlight on Optics

Abstract
We report on the generation of 192.3 J centered at 800 nm wavelength from a chirped-pulse amplification (CPA) Ti:sapphire laser system. The experimental results demonstrate that parasitic lasing can be suppressed successfully in the final amplifier based on a Ti:sapphire crystal of 150 mm in diameter. An over 50% pump-to-signal conversion efficiency was measured for the final amplifier by optimizing the time delay of two pump pulses and enhancing the injected seed energy. With 72% compressor throughput efficiency and 27 fs long compressed pulse duration obtained at a lower energy level, this laser could potentially support a compressed laser pulse of 5.13 PW peak power. The experimental results represent notable progress regarding the CPA laser.

© 2015 Optical Society of America​

 

[bobsm]

Chinese astronomers shed new light on black hole emissions

English.news.cn 2015-11-26 21:05:03

BEIJING, Nov. 26 (Xinhua) -- Chinese astronomers have discovered a new explanation for how black holes form and project jets of matter, marking one of the most significant findings in the field this year.

The formation of relativistic jets - streams of matter emitted nearing the speed of light - and accretion - the accumulation of cosmic dust particles near a black hole - remain one of the biggest mysteries of astrophysics.

Researchers from the Chinese Academy of Sciences (CAS) used the Great Canary Telescope in Spain and the Keck Observatory in the United States to monitor a black hole in the M81 galaxy hundreds of millions of light-years away from earth.

They unexpectedly discovered the black hole was emitting ultraluminous supersoft X-rays at velocities around 17 percent the speed of light.

"Most of astronomers didn't expect black holes to produce supersoft X-ray spectra by gobbling matter," said Liu Jifeng, a professor at CAS and a researcher at the National Astronomical Observatories under CAS, who led the research team.

"And they believed relativistic jets would only be produced by sources with soft, or low-energy, X-ray spectra or hard, high-energy, X-ray spectra."

"The new findings have provided a new perspective for astronomers to look into black hole accretion and the formation of jets," Liu said.

The teams research was recently published in top science journal Nature.

In recent years, Chinese astronomers have published several major findings in the world's top science journals, showcasing China's progress and great potential in the study and research of astronomy, said Yan Jun, the head of the National Astronomical Observatories.

Chinese astronomers shed new light on black hole emissions
- Xinhua | English.news.cn

 

[JSCh]

North Sea semi-submersible drilling rig delivered in Shandong(1/3)
2015-11-27 08:37 Xinhua

Photo taken on Nov. 26, 2015 shows the North Dragon, a North Sea semi-submersible drilling rig delivered by CIMC Raffles to North Sea Rigs AS in Yantai, east China's Shandong Province. North Dragon, which is the first semi-submersible drilling rig ever built by China having the capacity of operating in the Arctic area, is designed to operate in water depths of 500 meters, up to 1,200 meters and drill to depths of 8,000 meters. (Photo: Xinhua/Tang Ke)​

 

[JSCh]

Researchers discover how to manipulate nanomaterials
chinadaily.com.cn 2015-11-27 16:34

Xi'an Jiaotong University, one of China's top universities based in Xi'an, the capital of Shaanxi province, recently found a new method to significantly control the morphology and properties of micro/nano scale Zinc Oxide.

The method was found with advanced in situ transmission electron microscopy technology by the researchers of the school's micro/nano scale material behavior research center, and has significant implications for the application of ZnO nanowires in nano devices such as nano generators.

This research result has recently been published online in the top journal of the material field (NanoLetters,DOI: 10.1021/acs.nanolett.5b02852).

ZnO nanostructures have received wide attention in the world because of their excellent physical and chemical proerties, good biocompatibility and easy preparation, and they have broad potential applications in electronics, sensing, luminescence, power generation and biomedicine.

The testing of the ZnO nano structure and the overall performance is developing fast, but the material's performance has varied greatly in different research teams' results. The analysis showed that these differences were likely to be derived from the differences in material compositions, but the literature survey showed that there was little research on the relationship between the growth conditions and the properties of ZnO nanowires.

In view of the above problems, Wang Xiaoguang, doctoral student at the university's micro and nano center, found that the nanowires with circular and hexagonal cross sections can be obtained by slight adjustment of nanowire growth conditions after four years of research under the guidance of his advisoer Shan Zhiwei.

Other researchers involved in the research include the center's associate professor Chen Kai, doctoral student Zhang Yongqiang, master's degree student Wan Jingchun, professor Li Ju, professor Ma En and Dr. Oden Warren and Dr. Jason Oh at U.S. Hysitron company.

 

[JSCh]

New membrane improves energy harvesting by reverse electrodialysis
November 30, 2015 by Lisa Zyga


In the engineered asymmetric heterogeneous membrane, one type of asymmetry is the pore geometry of the PET membrane—as shown in b and c, the conical pores have a large opening on one side and a small opening on the other side of the membrane. The BCP membrane has pores of various sizes, as shown in d and e. Credit: Zhang, et al. ©2015 American Chemical Society

(Phys.org)—Researchers have constructed a new type of nanoporous membrane that does an exceptionally good job at selectively controlling ion transport—for instance, allowing negatively charged ions to pass through the pores, while prohibiting the passage of positively charged ions. To demonstrate one possible application, the researchers developed the membrane into an energy conversion device that harvests energy using its ability to separate charged particles. The technique is very similar to reverse electrodialysis, but the membrane's structure eliminates one of the limitations of traditional reverse electrodialysis, resulting in increased power generation.

The scientists, Zhen Zhang and Liping Wen from the Chinese Academy of Sciences and their coauthors, have published a paper on the new membrane in a recent issue of the Journal of the American Chemical Society.

The researchers describe the new membrane as an "engineered asymmetric heterogeneous membrane": "engineered" because it is a robust version of the fragile cell membranes used in living organisms, "asymmetric" because each side of the membrane filters the ions differently, and "heterogeneous" because each side is composed of a different material. Here, the researchers used two types of polymer materials: block copolymer (BCP) and polyethylene terephthalate (PET). Although not all asymmetric membranes are heterogeneous, heterogeneous ones have certain advantages such as being easier to fabricate and offering greater multifunctionality than asymmetric membranes made of a single material.

The greatest feature of the new membrane is that it promotes ion transport in one direction and inhibits it in the other direction. As a result, a much larger current is generated in one direction across the membrane than in the opposite direction, which is called "ionic current rectification." The new membrane has a rectification ratio of about 1075, which is more than twice the highest ratio reported to date. As the rectification ratio represents an asymmetric flow of charge, it arises from asymmetries in the new membrane (including chemical, geometrical, and charge asymmetries), and is highly desirable for various applications.

"This behavior is similar to the mechanism of semiconductor diodes for controlling the transport of electrons, and it represents the ability of directionally delivering specific types and controllable amounts of molecules or ions," Wen told Phys.org.

"It will open a new way to handle molecular or ion species in fluid and show broad application prospects in many fields. Similar to the semiconductor electronic circuits, the nanofluidic diode with a high rectification ratio represents the key building block for ionic circuits, which would allow for regulating, sensing, concentrating, and separating ions and molecules in electrolyte solutions. Also, in asymmetric-membrane-based photoelectric energy conversion systems, a high rectification ratio is favored, as the opposite transmembrane ionic transport will suppress the power density."

As an energy conversion device, the new membrane functions similar to reverse electrodialysis, in which energy can be harvested from the differences in the ion concentration (for example, negatively charged chlorine ions and positively charged potassium ions) on opposite sides of the membrane. Under a concentration gradient, the chlorine ions spontaneously diffuse across the membrane in order to lower the concentration gradient, and the energy generated by the current produced by the ion diffusion can be harvested.

The researchers predict that the new membrane can produce a power output of thousands of watts per square meter, which is equivalent to and potentially exceeding that generated by some commercially available reverse electrodialysis membranes. When investigating the reason for this high performance, the researchers found that the new membrane's asymmetries allow it to eliminate the "concentration polarization" problem that hinders traditional reverse electrodialysis membranes. The problem is that, on the side of the membrane with the low concentration of chlorine ions, the chlorine ions tend to clump together at the positively charged pore openings. This clumping creates a higher concentration of chlorine ions near the pore openings than in the bulk solution, which makes the concentration difference across the membrane seem lower than it actually is, causing fewer chlorine ions to diffuse across the membrane.

The new membrane not only eliminates this problem, but it actually make the chlorine ion concentration near the pore openings lower than in the bulk concentration, which promotes ion diffusion. The researchers attribute this advantage to the membrane's asymmetric structure and slightly negatively charged pores, in contrast to the symmetric structure and positively charged pore openings of traditional membranes.

"When the new developed membrane is applied in salinity gradient power generation, the output power density can be increased considerably due to the fact that the concentration polarization phenomenon that commonly exists in traditional reverse electrodialysis can be eliminated using the asymmetric bipolar structure, which provides guidance on the current ion-exchange-membrane-based energy conversion systems," Wen said.

In the future, the researchers hope to further improve the membranes so that they can be used for applications including power generation, water purification, and desalination.

"We would like to develop ionic diode membranes with more powerful functions by optimizing the composition of the selective membrane, increasing the porosity, and reducing the cost, which will finally meet the requirements for real-world applications," Wen said.

More information: Zhen Zhang, et al. "Engineered Asymmetric Heterogeneous Membrane: A Concentration-Gradient-Driven Energy Harvesting Device." J. Am. Chem. Soc., Article ASAP. DOI: 10.1021/jacs.5b09918

New membrane improves energy harvesting by reverse electrodialysis

 

[JSCh]

Oldest Peach Pits Found in China
Dec 1, 2015 02:03 PM ET // by Rossella Lorenzi

These are the fossilized peach pits.
Scientific Reports/Creative Commons​

The oldest peach pits have been found near a bus station in China, according to a new study that sheds new light on the little-known evolutionary history of the fruit.

The eight fossilized peach endocarps, or pits, date back more than two and a half million years. They were found by Tao Su, associate professor at Xishuangbanna Tropical Botanical Garden, when road construction near his house in Kunming, capital of Yunnan in southwest China, exposed a rock outcrop from the late Pliocene.

Preserved within the Pliocene layers, the fossils looked “strikingly modern,” according to Su. With colleague Peter Wilf, a professor of paleobotany at Pennsylvania State University, and others, Su detailed his findings last week in Scientific Reports.

“The fossils are identical to modern peach endocarps, including size comparable to smaller modern varieties, a single seed, a deep dorsal groove, and presence of deep pits and furrows,” the researchers wrote.

The discovery suggests that peaches, juicy and sweet, much like the ones we eat today, were a popular snack long before the humans arrived on the scene.

After analyzing the morphological characters of the pits, the researchers concluded they belonged to the genus Prunus and proposed a new species name, Prunus kunmingensis.

“We aim to provide an unambiguous epithet for the fossils in the absence of a whole-plant reconstruction,” the researchers said.

A popular tree fruit worldwide, with an annual production near 20 million tons, peach (Prunus persica) is widely believed to have originated in China. However, much of the evolutionary history of the fruit remains unknown.

The oldest evidence had been found within archaeological records dating back roughly 8,000 years, but no wild population has ever been found.

The discovery of Prunus kunmingensis supports the belief that the peach originated in China.

“The peach was a witness to the human colonization of China. It was there before humans, and through history we adapted to it and it to us,” Wilf said.

Several tests carried out at Penn State University confirmed that the pits, preserved in the Pliocene rocks along with many other plant fossils, are more than 2.5 million years old.

Electron microscope analysis showed that the seeds inside the flattened pits were mostly replaced by iron oxides, while radiocarbon dating of the fossils showed them to be older than the range of radiocarbon dating, which is about 50,000 years.

The researchers explained that peaches evolved their modern morphology under natural selection, with animals and primates snacking on the fleshy fruit and dispersing their seeds.

Much later, peach size and variety increased through domestication and breeding.

So what did Prunus kunmingensis look like? Su and colleagues compared the size correlation between pits and fruits in modern peaches, and concluded that the size of the fruit in the late Pliocene was about 5.2 cm (2.05 inches) in diameter.

“If you imagine the smallest commercial peach today, that’s what these would look like,” Wilf said.

“It’s something that would have had a fleshy, edible fruit around it,” he said. “It must have been delicious.”

Oldest Peach Pits Found in China : Discovery News

*************************
Maybe that is why peach feature frequently in Chinese traditional folklore and legend and in present day custom too.

 

[Martian2]

Taiwan's Plasmon-Coupled Organic Light Emitting Diode (PCOLED) lasts 27 times longer than OLED

Forget OLED: Taiwan-Based ITRI Unveils PCOLED With Display Lifetime Longer By 27 Times | Tech Times