News on China's scientific and technological development.

Scientists at Shanghai Institute of Applied Physics (SINAP), Chinese Academy of Sciences demonstrated a novel principle of seeded free electron lasers, Echo-Enabled Harmonic Generation (EEHG) on Shanghai Deep UV Free Electron Laser (SDUV-FEL) facility. The result was published on Nature Photonics.

Free-electron lasers have been successfully operated with ultra-high brightness and excellent transverse coherence at the x-ray wavelengths. One of the next goals for further improvement is full coherence. An obvious approach is to seed the free-electron laser interaction using a conventional source that has good temporal coherence.

The recent work done by the SINAP FEL team shows the first lasing of a free electron laser with the echo-enabled harmonic generation scheme, which is very promising for producing coherent laser at short wavelength down to the x-ray regime. The experiment facility combines a 135.4 MeV electron accelerator and an amplifier consisting of a series of undulator magnets.

The lasing is achieved at the third harmonic of the seed with a gain of about 100,000 over the spontaneous radiation. The measurements show a typical exponential growth and excellent spectral characteristics as well as good intensity stability.

It is now well-known that free-electron lasers (FELs) can provide tunable, high-intensity, ultrashort, coherent radiation for wide applications in biology, chemistry, physics, material science, etc. In the x-ray wavelength range, most of the FELs operate in the self-amplified spontaneous emission (SASE) mode.

With the advent of x-ray FELs, a new era of x-ray science has arrived. While the radiation from a SASE FEL has excellent transverse coherence, it typically has rather limited temporal coherence and relatively large statistical fluctuations, because a SASE FEL starts from electron beam shot noise.

In order to meet the desire for excellent temporal coherence in many applications such as soft x-ray resonant inelastic scattering, spectroscopic studies of correlated electron materials, etc, various high-gain seeded FEL schemes, external seeding5, or self-seeding have been developed for producing stable and fully coherent laser pulse from deep UV down to the x-ray regime. Among these schemes, the latest proposed Echo-Enabled Harmonic Generation (EEHG) is a very promising candidate for fully coherent short wavelength FEL with a single stage of seeded FEL setup.

Experimental demonstrations of EEHG mechanism have been performed at the Shanghai Deep-Ultra Violet FEL (SDUV-FEL) facility and the Next Linear Collider Test Accelerator (NLCTA) at SLAC National Accelerator Laboratory. However, no amplification has been observed in these experiments. In this letter, for the first time, the EEHG signal has been successfully amplified by the long radiator at the SDUV-FEL.

The experimental results agree very well with theoretical predictions: The pre-micro-bunched electron beam with EEHG technique is amplified with a gain larger than 1000; The central wavelength of the HGHG radiation is shorter than the 3rd harmonic of the seed laser because of the negative energy chirp in the electron beam; The central wavelength of the EEHG radiation is different from HGHG due to a different wavelength dependence on the energy chirp; The bandwidths of HGHG and EEHG spectrum are different due to a different bandwidth dependence on the nonlinear energy chirp.

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China National Institute of Metrology has recently rolled out an automated loading and unloading device for large weighing device test under a temperature and humidity environment. According to WANG Jian, head of the Mass Density Lab under the Institute, the experts approved device is made up of a proprietary automated loading and unloading system, a temperature and humidity test chamber, and an electric mover.

With the help of the robot loading and unloading system, it takes only 12 minutes to complete a temperature or wet spot return test in a class 10 loading process. Without entering the test chamber, a tester is able to complete the whole weighing test under different temperature and humidity conditions, greatly shortened the time to test a large weighing device.

Meanwhile, both the driver and electrical components are installed outside of the temperature and humidity test chamber, avoiding the stability and reliability of the equipment being compromised by the hot and humid conditions.

Compared with the similar devices developed at home and abroad, the new device is designed to be a mechatronic integration, enjoying numerous merits, including a new hardware structure, sophisticated combination code design, rational configuration, and full functional programs.

The system has been running smoothly, accommodating weighing performance test, repetition test, and husk test for large (300-3,000 kg), special, and irregular shaped weighing devices in a temperature and humidity environment. The system has registered a relative uncertainty better than 5×10-6.

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Supercomputing environment and associated application, a project undertaken by Chinese Academy of Sciences, passed an acceptance check on April 22, 2011. CHI Xuebin, project leader, and a research fellow at Chinese Academy of Sciences Computer Network Information Center, told reporters that the supercomputing environment allows CAS to extend its supercomputing capacity and associated applications to the entire country.

In addition to the Headquarters in Beijing, CAS will build 8 branches in Kunming, Dalian, Qingdao and other cities, covering bioinformatics, materials science, climate modeling among others.

Meanwhile, the project has attracted the participation of 17 institutional centers, including CAS Purple Mountain Observatory, CAS Shanghai Astronomical Observatory, CAS Institute of Ecology and Geography in Xinjiang, and CAS Institute of Matter Structures in Fujian. A supercomputing environment with a three-tiered grid architecture has been created to link the Headquarters, branches, and institutional centers

The supercomputing environment is able to aggregate general-purpose CPU computing power for more than 300 trillion times, or aggregate GPU computing power for nearly 3,000 trillion times. Its overall aggregated computing power ranks first in the country.

According to a briefing, the project has developed 197 application programs, covering earth, life, information, aviation, physics, chemistry, materials, astronomy among others. CAS Computer Network Information Center, in collaboration with CAS Institute of Computing Technology, has developed a proprietary network program SCE, and applied for an international patent.

Up to date, CAS supercomputing environment has provided 68 applications to the users in the areas of computational physics, computational chemistry, materials science, fluid mechanics, engineering computation among others.

The grid assignments submitted to the Environment has reached more than 50,000 in number, with a combined walltime for more than 6 million CPU hours.

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An S-band 10MeV-20kW electron linear accelerator, jointly developed by Wuxi Aibang Radiation Technology and CAS Institute of High Energy Physics, has recently passed the experts’ verification check.

The accelerator, tested by China Institute of Metrology, is able to generate 10.2MeV of energy, at a nominal beam power of 22.1kW, reaching and exceeding the design specifications of 10MeV and 20kW, making itself the most powerful and advanced industrial 10MeV accelerator.

According to a briefing, the accelerator can be employed to process different stuff under room temperature, desirable for the sterilization of medical and health supplies, food, and agricultural by-products, freshness preservation, chemical and medical polymer property modification, and semiconductor performance enhancement.

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China's homegrown standard for fourth-generation wireless technology has started to make its way abroad.

By June, nine telecom operators across the world had introduced commercial services on Time Division-Long Term Evolution, or TD-LTE, networks, according to China Mobile Communications Corp.

TD-LTE has been promoted by China Mobile since 2008. In October 2010, the International Telecommunication Union selected the upgraded version of the technology, TD-LTE Advanced, to be one of the six international standards to be used for 4G networks.

The union placed the six different standards into two categories, "LTE-Advanced" and "WirelessMAN-Advanced".

Most of the world's telecom carriers said they prefer using "LTE-Advanced", which consists of TD-LTE and Frequency Division Duplex LTE, or FDD LTE.

Currently, TD-LTE's development still lags far behind FDD LTE's.

Analysts say TD-LTE technology has become the first China-initiated mobile standard to be truly used globally. Its homegrown 3G predecessor, known as TD-SCDMA, failed to achieve that goal because it was not as well developed as its rival 3G technologies and it wasn't used outside China.

Among the first telecom carriers to deploy TD-LTE commercial networks were Mobily in Saudi Arabia, Softbank Corp in Japan, and SKY Brazil in Brazil. Another 16 operators have announced commercial plans for TD-LTE networks, said Li Zhengmao, an executive vice-president with China Mobile.

Public figures show 36 TD-LTE trial networks existed in the world by June."2012 and 2013 could bring the greatest of historic opportunities for TD-LTE technology's globalization," Li told China Daily.

Li said the number of telecom operators in the world that have applied for mobile broadband spectrum has hit a peak, meaning such operators will soon have to choose which 4G technologies they want to use.

"Now is a very important time for TD-LTE to draw carriers' attention," Li said.

Some foreign carriers have praised the Chinese 4G technology in public. Sanjay Kapoor, chief executive officer of Bharti Airtel for India and South Asia, said the company is in favor of the standard.

"It is easy to deploy and it gives customers the best experience," he said at the GSMA Mobile Asia Expo, an event organized by an association of mobile operators, in Shanghai in June.

Ted Matsumoto, chief strategic adviser to the board of Softbank Corp, said Softbank has started moving faster to build and deploy a TD-LTE network since the beginning of the year and now has more than 100,000 users in Japan. The number of TD-LTE base stations operating in Japan is expected to reach about 10,000 by the end of the year, up from the current 7,000, he added. In addition, Softbank is negotiating with China Mobile "on TD-LTE roaming in China and Japan", Matsumoto said in June.

Sources in China Mobile said some US telecom operators have shown interest in building a TD-LTE network, suggesting that China's homegrown 4G technology has a chance of entering a developed telecom market in North America.

The Global TD-LTE Initiative, the international TD-LTE alliance launched by China Mobile in 2011, has attracted 48 telecom carriers so far. The initiative is meant to promote the convergence of TD-LTE and FDD LTE.

As announced in the initiative operator's action plan in February, 500,000 TD-LTE base stations are to be deployed globally by 2014. They are to have more than 100 terminal models, enough to provide service to more than 2 billion people.

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Ningbo Institute of Materials Technology and Engineering (NIMTE), dedicating to developing, manufacturing and marketing solid oxide fuel cell technology (SOFC) that generates clean electricity in compact form for both mobile and stationary applications, announced that an SOFC stack with new high output power was successfully assembled and tested.

The SOFC stack was assembled by 240 pieces anode-supported cells, which was divided into four stack series. Each stack series includes 60 pieces cells. The average open circuit voltage of single cell was more than 1. 1 V.

The stack obtained a maximum power of 5.2 kW and operating power of 4.54 kW with the fuel utilization of 71.4% and 47% respectively.

The high output power SOFC stack shows that the yield and consistency of single cells manufactured by SOFC group in NIMTE were greatly improved.

This program was supported by the Ministry of Science and Technology of China, the Chinese Academy of Sciences and the Ningbo Government.

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Black silicon is a kind of silicon material with low reflection. Comparing with conventional silicon material, black silicon exhibits strong light absorption capability and can be used in solar cells industry.

In mid-June, researcher XIA Yang and his team in the Key Laboratory of Microelectronics Devices & Integrated Technology in Institute of Microelectronics of the Chinese Academy of Sciences (IMECAS) firstly proposed to produce black silicon by using plasma immersion ion implantation (PIII) technology.

The microstructure, optical absorbance and lifetime of minority carriers of the black silicon were characterized by scanning electron microscopy (SEM), UV-VIS-NIR spectrophotometer and microwave photoconductive decay (µ-PCD), respectively.

The results show that the black silicon has a porous structure. The average absorbance of the black silicon is above 94% in the visible region. The average lifetime of minority carriers in the black silicon is 5.68 µs.

Researchers investigated the effect of immersion parameters on the black silicon and found that the gas flux ratio of SF_6 to O_2 plays an important role in the microstructure and properties, and its optimum value is 2.80. The average reflection of the black silicon is 0.5% in visible wavelength region, which can compare with the black silicon achieved by irradiating femtosecond laser pulses. Meanwhile, PIII, as a low cost and high efficiency process, is more proposed for mass production.

The relevant research papers are published on the journal of Solar Energy, Energy Procedia, Journal of Electron Spectroscopy and Related Phenomena, Acta Physica Sinica and so on. The project team also applied for more than 30 patents.

By optimizing the textured structure and following-up process, researchers obtained 17.46% average efficiency solar cells based on PIII textured 156mm×156mm multicrystal silicon, and the highest efficiency of solar cells is up to 17.65% in this patch.

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China Internet Network Information Center (CNNIC) officially released Secure Domain Name System (SDNS), which provides the massive netizens with secure, intelligent and high-speed Internet access resolution service.

As the ccTLD registry, CNNIC has got almost twenty years' experience in domain name research & application and domain name resolution & operation.

After release of Country Domain Name System (CDNS) in June 2011 offering the national domain name users with domain name resolution service (authoritative resolution) free of charge, CNNIC now presents the massive Internet end users with another service free of charge, namely, SDNS (recursive resolution).

Relying on the three major technical strengths, CNNIC accomplished from independent research and development of high-performance resolution software system, reliable Internet server cluster and professional operation monitoring platform, SDNS can further optimize netizens’ experience effectively through improving the Internet access resolution speed and minimizing unexpected DNS interruption or hijack.

Meanwhile, SDNS can implement omni-directional real-time monitoring of resolution service status from the numerous data monitoring spots distributed nationwide on the ccTLD security monitoring platform, and also expand service capacity rapidly based on changes in user access quantity, thereby guaranteeing a continuous, reliable and stable service.

Address for SDNS:
Preferred DNS server: 1.2.4.8
Standby DNS server: 210.2.4.8

Please, Log in or Register to view URLs content!

for more information

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Scientists in central China's Hubei province said they have assembled the country's first optical clock, which measures time more precisely than traditional atomic timekeepers.

The optical clock, based on a single calcium ion, can remain accurate within one second for more than 10 million years, said Gao Kelin, a researcher at the Hubei Academy of Sciences.

Gao said his group uses electric and magnetic fields to "trap" a calcium ion for more than 15 days, allowing researchers to pinpoint the passage of time by tracking the ion's atomic movement.

"Unlike microwave clocks, which track atomic movement in the microwave range, optical clocks observe the optical range, which can reduce uncertainty by 100 to 1,000 times," Gao said.

The breakthrough has made China the seventh country in the world to build such a clock following the U.S., Germany, the UK, Canada, Austria and Japan, Gao said.

Atomic clocks, including microwave and optical clocks, can be used to provide extremely precise measurements of time that are used in fields ranging from telecommunications to the manufacture of precision instruments.

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China installed a dome-shaped radar on the roof of a four-story building on the Zhubi reef in South China Sea in May, Philippine media reported, and Manila was fully aware of it. 'Government told of China buildup 2 months ago', the Daily Inquirer website claimed in a July 17th article with the same title.

The Inquirer report, quoting Palawan defense sources, says the Aquino administration was notified two month ago of Chinese military construction on islands in the Spratly (China’s Nansha Islands), Subi Reef and Mischief Reef (known as Zhubi Reef and Meiji Reef in Chinese respectively). Meiji Reef is reportedly fully occupied by China and its construction on Zhubi Reef is still under way.

Colonel Neil Estrella, spokesperson for the Philippine’s West Command, said the military was aware of the Chinese activities and revealed that China has also “completed the construction of a helipad and the placement of buoys in a narrow channel to guide marine vessels into the reef’s inner lagoon”.

Eugenio Bito-onon, mayor of a Kalayan town, confirmed observations of visible Chinese structures on Zhubi Reef, saying the Chinese had only recently removed the scaffolding on the tall building that has a radar on top.

What is noteworthy is that Kalayan Island, one of the Nansha islands in the South China Sea, was illegally occupied by the Philippines and is still under its control.

“(Philippine) fishermen have been able to approach that island and they see what is going on there,” Bito-onon said, citing local fishermen’s accounts.

Radar could be used for weather forecasting as well as monitoring ships sailing in the region.

On May 20, China’s State Oceanic Administration (SOA) announced to start offering weather and marine environmental forecasts of Huangyan Island and its nearby islets. Starting June 9, Hainan TV channel daily broadcasts weather and marine forecasts of the region at 7 pm.

Wang Feng, director of SOA’s marine forecast and disaster reduction division, said in an interview with China’s Youth Daily that providing forecasts is a public service for Chinese fishermen and has no bearing on the ongoing standoff with Manila.

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