News on China's scientific and technological development.

bladerunner said:

Deep sea dives open to women

The first Chinese female astronaut, Liu Yang, captured the country's imagination when she took a trip to space in June and the nation is set to welcome a first female oceanaut in 2013.

China plans to recruit four to six oceanauts next year, and possibly the first female Chinese deep-sea explorer will be among them, as the male-only requirement is being lifted from the selection process, said Liu Feng, commander of the Jiaolong's 7,000-meter dive project.

The requirements for female and male oceanauts are the same and concern physical endurance and psychological strength, said Liu.

The National Deep Sea Center is working on new selection criteria, training program and assessment standards for future oceanauts, Xinhua News Agency quoted Liu Baohua, director of the center, as saying.

For female astronauts, the selection criteria are tough. They must, for instance, be married, for the influence space has on humans is still unknown. However, the marital status of potential female oceanauts will not matter, said Fu Wentao, one of the country's three oceanauts in the 7,000-meter dive project.

Liu Feng said women are often more cautious than men, which can be important in a deep-sea dive.

When a submersible, a vehicle similar to a submarine, reaches 200 meters below sea level, no sunlight can reach it and it becomes totally black outside. A cautious person is needed so they can be aware of any little changes in the dark, Liu Feng said.

However, women have to overcome many obstacles to become oceanauts, said Liu Xincheng, deputy director of the North China Sea Branch of State Oceanic Administration. Because the space in Jiaolong, China's manned submersible, is very small, only big enough for three people to sit together, going to the toilet can be difficult for women during a dive of more than 10 hours.

Fu, the 30-year-old oceanaut, took an empty bottle for long dives on the Jiaolong to urinate in. Bottles and paper nappies are used by oceanauts in a submersible instead of a toilet.

"It will be inconvenient for female oceanauts during long dives because there is no bathroom on board," Fu said.

Unlike the Shenzhou IX spacecraft, on which astronauts had separate sleeping areas and bathrooms, Jiaolong, which is 8.2 meters long and 3.4 meters high, only has enough space for three people to sit.

"From getting on board to coming out, you can stay in there for at least 12 hours, which poses great difficulties, physically and mentally," Fu said, adding that oceanauts do not drink water the night before a dive.

Cui Weicheng, deputy commander of the 7,000-meter dive project and Jiaolong co-designer, said a person's sex is not an obstacle for oceanaut selection, saying once on board, there are no men and women - just oceanauts and scientists. China now has three oceanauts - Ye Cong, Tang Jialing and Fu Wentao, all male.

In 2006, China began selecting oceanauts. The requirements are as tough as those for astronauts. An oceanaut must be familiar with the structure, equipment and control of a submersible. Until now oceanauts were required to be men, under 35 years of age and with a bachelor degree or above in shipbuilding, machinery or electronics. They also had to pass a rigorous physical exam.

As more oceanauts are expected to pursue a career in deep-sea diving, the country is also investing in new facilities for deep-sea exploration.

The construction of a new National Deep Sea Center is expected to begin in Qingdao, Shandong province, this year. With an estimated cost of 495 million yuan ($78 million), the center will provide technical support for the country's deep-sea exploration and development, said Liu Baohua, center director.

In June, China's manned submersible, Jiaolong, set a new national dive record after reaching 7,062 meters below sea level during its fifth dive into the Mariana Trench in the western Pacific Ocean.

In order to better use the submersible, Liu Feng said a 4,000-ton support ship will be built before 2015 and another manned submersible with a designed depth of 4,500 meters is also under construction.

Please, Log in or Register to view URLs content!

Click to expand...

EAST (Experimental Advanced Superconducting Tokamak) at Institute of Plasma Physics, CAS undertook an extensive upgrade during the last shutdown in 2011, from Plasma Facing Components (PFC), poloidal field (PF) power supply, and auxiliary heating to many key diagnostic systems.

With the advent of significantly augmented auxiliary heating, operation and diagnostic capabilities, EAST has carried out an extensive experimental campaign since Spring 2012, aiming at exploring the boundary of the EAST operation space with favorable stability and confinement and developing suitable means to expand this space toward steady-state operation.

To these ends, the campaign has focused on ICRH (ion cyclotron resonance heating) and LHCD (lower hybrid current drive) physics, MHD (magneto-Hydro-Dynamics) and ELM (edge local mode) control, L-H transition and pedestal physics, divertor physics and emerging PSI (plasma Surface Interactions) issues under long pulse operation conditions, and developing advanced scenarios that integrate high performance with long pulse operations. EAST 2012 campaign has been accomplished on July 10th.

Progress has been made on EAST during this new experimental campaign on physics and technology fronts, with the following key achivements:

* Achieved long pulse H-modes over 30 s with LHCD and ICRH, facilitated by active lithium (Li) and cryopumping.
* Achieved long pulse divertor plasma up to 411s, which was fully driven by LHCD with active-cooled PFC and internal cryopump.
* Achieved a long-pulse Enhanced (EDA) H-mode regime and further verified the role of zonal flows in the L-H transition by direct gas dynamic imaging.
* Demonstrated change in edge magnetic topology induced by LHCD, which have potentially significant impacts on divertor and edge physics, such as power deposition, edge rotation and L-H transition, etc.
* Observed a lower L-H transition power threshold for the ion drift direction away from the dominant divertor in the RF heated discharges in EAST, opposite to the previous observations in other tokamak.
* Upgraded RF and LH systems to a total power of 8 MW, implemented more than 10 new diagnostics, and developed a new CW pellet injection system and supersonic molecule beam injection (SMBI) system for ELM mitigation and precise density feedback control.
* Successfully demonstrated ELM control by LHW(lower hybrid WAVE) power modulation, SMBI, D2 pellet and innovative Li pellet injection.
In order to facilitate long pulse operations, half of carbon tiles on the wall and divertor surfaces were replaced with molybdenum tiles during the last EAST shutdown, allowing baking up to 250 °C. In addition, the Li evaporation system was upgraded to improve coating uniformity. This, along with enhanced wall baking capability and active divertor pumping, greatly facilitates recycling control. Reproducible, 32 s long pule H-modes have been achieved in EAST driven by LHCD, assisted by ICRH. Figure 1 shows a typical long pulse H-mode plasma discharge in EAST obtained under the double null (DN) divertor configuration. This particular discharge exhibits type-III like small ELMs with H98,y2 ~ 0.9, due to marginal auxiliary heating, with combined LHCD and ICRH input power about 2.5 MW. Stationary type-I like ELMy H-modes with higher confinement quality have also been obtained in EAST by further increasing RF heating.

* Over 400s long pulse steady-state divertor discharge has been realized with the line average density being maintained at ~1.5x1019 m-3 and temperature close to 2keV, and all the plasma parameters, including wall temperature, reaching a truly stead-state condition. This has been achieved using the following key approaches: (1) All PFCs have been actively cooled, with internal cryopump activating; (2) Real-time plasma control has been applied to maintain plasma shape, density and effective coupling for LHW; (3) Strike point sweeping and varying plasma configuration from USN to DN and LSN have been applied during the discharge for minimizing divertor heat load, impurity influxes and plasma wall interactions under the steady-state condition; (4) Further, one key issue is to keep all PF coil currents at a minimum level (<2kA), well below the critical current limit (14.5kA) to maintain a large safe operation margin for superconducting coils, which is crucial for future ITER long pulse (400s) operations.

* It is remarkable that the access to H-modes in EAST exhibits a lower power threshold for the ion drift away from the dominant X-point, in striking contrast to other tokamaks or STs. EAST has identical top and bottom divertor geometry with a flexible poloidal field control system to enable operations with both single null and double null divertor configurations. This greatly facilitates the assessment of the access to H-mode with respect to the ion ÑB drift direction by simply changing the divertor configuration between lower single null (LSN) and upper single null (USN) configurations during the same discharge. For normal BT, it requires lower LHCD or LHCD+ICRH power to access the H-mode with USN, i.e., with the ion ÑB drift away from the dominant divertor, while LSN is favorable for reversed BT, opposite to the observations in other tokamak or ST experiments with dominant NB heating. This may have significant implications for ITER, which only accommodates the LSN configuration with dominant electron heating.

* LHCD appears to induce a profound change in the edge magnetic topology by driving currents in the edge plasma, as evidenced by the non-rotating Helical Current Filaments (HCFs) flowing along the magnetic field lines in the SOL,. This leads to the splitting of divertor strike points (SP) with similar effects to the resonance magnetic perturbations (RMPs), as manifested in heat and particle flux profiles. The change in edge topology has been qualitatively modeled by including the HCFs. The 3D edge topology induced by LHCD can be actively controlled by adjusting the plasma edge safety factor and LHCD power.

Different techniques have been explored for ELM control during this campaign, including modulating LHW power, SMBI, injection of Li and D2 pellets. Effective ELM mitigation has been achieved by LHW power modulation and SMBI. In addition, ELM pacing has been successfully achieved with D2 pellet injection from both high field side (HFS) and low field side (LFS). Furthermore, ELM pacing has also been demonstrated, for the first time in EAST, using the innovative Li-pellet injection technique.

In summary, EAST has started to demonstrate its long pulse operation capability with improved PFCs, active Li and cryopuming, together with new control tools such as SMBI, low/high field side pellet injection, and Li-pellet injection. This has enabled study of new H-mode physics in RF dominated regimes and issues related to long pulse operations.

The EAST 2013 experimental campaign is foreseen for fall 2013 with more than 20MW CW H&CD and ITER-like W mono-block divertor, which will certainly produce more exciting results. International contributions from USA (GA, PPPL, MIT, UCSD, ORNL), France (CEA), Japan (NIFS, JAEA), Korea (NFRI), Germany (IPP, FZJ) and ITER IO are one of the key ingredients for these achievements, and are much appreciated.

Click to expand...

Waveform-controlled THz radiation is of great importance due to its potential application in THz imaging and coherent control of molecular dynamics. Recently, Bai Ya et. al. in Prof. LI Ruxin and Prof. XU Zhizhan’s group at Shanghai Institute of Optics and Fine Mechanics, Chinese Academy of Sciences(SIOM), have reported a novel scheme to generate waveform-controlled THz radiation from plasma filaments in air produced by carrier-envelope-phase (CEP) stabilized few-cycle laser puluses [Phys. Rev. Lett. 108, 255004 (2012).].

Researchers utilize a home-built few-cycle IR laser system, which composes of a Ti:sapphire pumped optical parametric amplifier (OPA) system and a hollow fiber compressor [Opt. Express 19, 6783 (2011).], to carry out the experiments. The CEP-stabilized 10fs-long (~1.7 optical cycles) laser pulses at 1.8mm was focused by concave mirror and collapsed into air filament. They found that the generated THz waveforms can be controlled by varying the filament length and the CEP of driving laser pulses.

In order to investigate the evolution of driving laser pulse and THz radiation in the filament, a sharp stainless steel blade was inserted into the plasma column to stop the filament, which can be moved by a motor stage along the laser propagation direction, so that the detection of THz radiation from the upstream unperturbed filament is lest influenced, and then the integrated THz signals from filaments of different lengths are measured.

In model calculation, the researchers consider the THz emission originated from the transient photocurrent driven by the propagating intense few-cycle laser fields in the plasma. Since the Rayleigh length is no longer valid in filament, they initialized the idea the modified Gouy phase shift that is characterized by effective length zeff. The modified Gouy phase shift due to the extension of filament confirms the previous theoretical prediction that the Gouy phase shift stems from transverse spatial confinement of a finite beam. In simulation, the THz amplitude as a function of filament length is found in consistence with the measured results.

Understanding the laser phase effect and propagation effects on the THz radiation from the few-cycle laser pulse produced filament is crucial for the THz generation based CEP metrology and the generation of intense and waveform-controlled THz radiation.

This work is supported by Chinese Academy of Sciences, Chinese Ministry of Science and Technology, NNSF of China, 973 Program of China, and Shanghai Commission of Science and Technology.

Click to expand...

Exploring new recycled heterogeneous catalytic materials used in the transformation of organic matter and the degradation of pollutants is one of the hotspot researches on material chemistry and catalytic chemistry. Metal–organic frameworks (MOFs) have been emerging as very promising functional materials for gas storage, heterogeneous catalysis, due to their high surface area, porosity and chemical tunability in the past few years.

The research group headed by Prof. CAO Rong at Fujian Institute of Research on the Structure of Matter (FJIRSM), Chinese Academy of Sciences (CAS) has developed a series of new heterogeneous catalysts based on MOFs. A series of highly dispersed palladium nanoparticles (Pd NPs) supported on the amine functionalized MOFs as excellent catalysts have been prepared.

The Pd NPs encapsulated in the mesoporous cages of amine-functionalized MOFs MIL-101(Cr)–NH2 exhibited high activities in the dehalogenation of aryl chlorides in water under mild conditions (J.Catal.2012,292,111). The Pd NPs supported on inexpensive amine-functionalized, mixed-linker MIXMOFs based on MIL-53(Al) showed high activities in Heck reactions (ChemPlusChem,2012,77,106). The Pd NPs supported on amine-functionalized MOF MIL-53(Al)-NH2 exhibited high activities in Suzuki reactions (Catal. Commun.,2011,14,27). 　

The Pd NPs encapsulated in the mesoporous cages of the MIL-101(Cr) prepared using the wetness impregnation method exhibited extremely high activities in the direct C2 arylation of substituted indoles with iodobenzenes (Chem.Eur.J.,2011,17,12706). All the nanocatalysts are easily recoverable and can be reused several times without leaching into solution and loss of activity.

The research group has also discovered homochiral nickel coordination polymers based on salen(Ni) metalloligands, which can be used for alkene epoxidation (Inorg. Chem.,2011,50,2191).

Click to expand...

The TD-LTE ecosystem is ramping up quickly, but it is unclear if this nascent technology will burst out of the gate with the robust performance that characterized early products supporting the FDD flavor of LTE, according to Nigel Wright.

FDD LTE devices quickly ramped up in terms of performance, in part, because U.S. operators such as Verizon Wireless and AT&T Mobility were driving that technology's deployment, and "North American operators have a huge track record of pushing back on their supply chain to get it right," said Wright, vice president of wireless product marketing at test and measurement products vendor Spirent Communications.

"I do believe a successful piece of the successful rollout of FDD LTE was that the leading North American carriers were involved," he said.

In the United States, TD-LTE is being backed by Clearwire which doesn't have the financial ballast to make it a heavyweight when it comes commanding vendors to up the quality of their products. Another TD-LTE backer is China Mobile, which certainly has influence as the world's largest mobile operator but isn't known for prodding its vendors on performance standards, at least not as assertively as North American operators, said Wright.

However, he said China appears dedicated to making TD-LTE a success since its homegrown TD-SCDMA technology had only limited regional success. Last month, Spirent announced that China Telecommunications Technology Labs, a national-level telecom research institution of China's Ministry of Industry and Information Technology, selected the Spirent VR5 HD Spatial Channel Emulator for use in TD-LTE testing. Since one of its core functions is testing and certification of telecom products, CTTL will likely play a key role in the commercial readiness of TD-LTE.

Further, there is growing competition among vendors that want to play in the TD-LTE space. Wright noted there are at least 15 chipset vendors chasing down TD-LTE. Many of them, such as Sequans Communications and Altair Semiconductor, previously dedicated their efforts to WiMAX.

Early TD-LTE deployments might be role models for future rollouts. Softbank's TD-LTE network in Japan "provides a lot of insight into how these networks might be structure going forward, with lots of microcells," Wright said. He envisions operators using FDD LTE in macrocell networks and supplementing those with TD-LTE in microcells

TD-LTE, because it requires synchronization between base stations, offers advantages in terms of interference mitigation that might make it attractive in a small cell environment, said Wright. This is particularly true in place such as Europe, where operators won FDD spectrum for WCDMA along with TDD spectrum that has largely sat unused.

Given the fact that there is considerable effort being applied to TD-LTE development worldwide, "it doesn't seem unreasonable to think that in the next three or four years it really could be 25 percent of the global market," said Wright. "So we're planning accordingly because that's a pretty significant opportunity."

He said TD-LTE could become popular in markets where device cost is critical. It is cheaper to build a single-mode TD-LTE device because it doesn't requires a lot of complex RF components that FDD needs, such as a duplexer to avoid interference in an FDD system. "In TDD, you just need to switch between the transmitter and the receiver," Wright said.

One market to watch is India, which mandated TD-LTE as the technology to use with Broadband Wireless Access licenses. Since 3G hasn't taken off in India, there really is no need to offer more expensive multimode devices that include 3G, Wright said.

"TD-LTE's future depends on adoption in large markets such as China and India," he added.

So far, Spirent's TD-LTE efforts have been largely focused on conformance testing. "As the device ecosystem starts to ramp up, we expect to see much more demand for performance testing," said Wright, adding "We will be adding TD-LTE to pretty much all of our device testing solutions."

TD-LTE testing efforts are ramping up quickly. Last week Huawei announced it had established open TD-LTE interoperability testing labs in Xi'an and Shenzhen. "The labs were established to cooperate with chipset, device and application partners for the purpose of creating an open and win-win LTE ecosystem while driving end-to-end TD-LTE maturation and commercialization," said Huawei.

In April of this year, Huawei and Intel established another joint interoperability testing lab in Beijing to promote the development of the TD-LTE ecosystem.

Click to expand...

Early detection of cancer increases the chances of successful treatment and patient survival rate. Achieving rapid, low-cost and sensitive cancer diagnosis remains a challenge due to the complexities of this disease. Engineered nanoparticles have been used to provide diagnostic, therapeutic, and prognostic information about the status of disease. However, this approach can lead to an excess of ligands on the nanoparticle surface and causes nonspecific binding and aggregation of nanoparticles, which decreases detection sensitivity.

In a recent study, Professor YAN Xiyun’s group at the Institute of Biophysics, Chinese Academy of Sciences reported a new magnetoferritin nanoparticle for cancer diagnosis and treatment. This is another major breakthrough after Professor YAN’s discovery on the intrinsic enzyme-like activity of inorganic nanomaterials (Nature Nanotechnology, 2007).

In this study, by utilizing the newly found biological property of inorganic nanomaterials, YAN’s group biomimetically synthesized a new magnetoferritin nanoparticle in collaboration with Professor PAN Yongxin at the Institute of Geology and Geophysics, Chinese Academy of Sciences.

The new nanoparticle has an iron oxide core encapsulated in a ferritin protein shell. The protein shell binds specifically to tumour cells, while the inorganic core exhibits peroxidase activity that visualizes the tumours in the presence of chromogen substrates. They examined 474 clinical specimens from patients with nine types of cancer and verified that these nanoparticles can distinguish cancerous cells from normal cells with a sensitivity of 98% and specificity of 95%.

Compared with traditional antibody-based immunohistochemistry, this new magnetoferritin nanoparticle-based method is more rapid (It only takes 1 hour, rather than 4 hours in immunohistochemistry) and simpler to implement since it achieves tumours targeting and visualization in one step, avoiding multi-step incubations with expensive and unstable antibodies, and repeated washing procedures of immunohistochemistry. This greatly shortens diagnostic time and reduces the cost, and thus has significant implications for cancer diagnosis.

The research was supported by grants from the National Science and Technology Major Project and the Chinese Academy of Sciences and published in the latest issue of Nature Nanotechnology.

Click to expand...

Spectroscopic probes have been used in various fields because of their high sensitivity and great temporal and spatial sampling capability. The development of new spectroscopic probes with superior properties is important for the detection of different analytes.

Prof. MA Huimin. Dr. SHI Wen and their co-workers from CAS Key Laboratory of Analytical Chemistry for Living Biosystems have developed a series of new spectroscopic probes for bio-molecules (Chem. Commun. 2008, 1856-1858; Chem. Commun. 2010, 46, 2560-2562; Chem. Commun. 2011, 47, 8638-8640; Chem. Eur. J. 2010, 16, 6638-6643; Chem. Eur. J. 2012, 18, 925-930) and published an invited Feature Article entitled “Spectroscopic probes with changeable π-conjugated system” in Chem. Commun. (2012, doi: 10.1039/ C2CC33366J).

Recently the researchers designed a tunable ratiometric pH probe based on carbon nanodots. Cell imaging studies showed that the probe can be distributed in the whole cells instead of the specific organelles such as endosomes or lysosomes, which demonstrates its good biocompatibility and intracellular dispersibility.

Quantitative determinations of intracellular pH of intact Hela cells and the pH fluctuations associated with oxidative stress have been successfully performed with the probe. Decrease of intracellular reduced glutathione (GSH) leads to the acidification of cells, but GSH above its normal level has no obvious effect. Moreover, elevated ClO- does not decrease the intracellular pH as H2O2 does.

These observations have revealed an interesting phenomenon that the disturbance of oxidative stress usually decreases rather than increases the intracellular pH (unidirectional change). In addition, the proposed pH probe may have a great potential for quantitatively monitoring the intracellular pH fluctuations under different stimuli.

This result has been published in Angew. Chem. Int. Ed. 2012, 51, 6432-6435. The research is supported by National Nature Science Foundation of China, Ministry of Science and Technology of China and the Chinese Academy of Sciences.

Click to expand...