Friday, February 11, 2011

World's First Programmable Nanoprocessor: Nanowire Tiles Can Perform Arithmetic and Logical Functions

ScienceDaily (Feb. 9, 2011) — Engineers and scientists collaborating at Harvard University and the MITRE Corporation have developed and demonstrated the world's first programmable nanoprocessor.


The groundbreaking prototype computer system, described in a paper appearing in the journal Nature, represents a significant step forward in the complexity of computer circuits that can be assembled from synthesized nanometer-scale components.

It also represents an advance because these ultra-tiny nanocircuits can be programmed electronically to perform a number of basic arithmetic and logical functions.

"This work represents a quantum jump forward in the complexity and function of circuits built from the bottom up, and thus demonstrates that this bottom-up paradigm, which is distinct from the way commercial circuits are built today, can yield nanoprocessors and other integrated systems of the future," says principal investigator Charles M. Lieber, who holds a joint appointment at Harvard's Department of Chemistry and Chemical Biology and School of Engineering and Applied Sciences.

The work was enabled by advances in the design and synthesis of nanowire building blocks. These nanowire components now demonstrate the reproducibility needed to build functional electronic circuits, and also do so at a size and material complexity difficult to achieve by traditional top-down approaches.

Moreover, the tiled architecture is fully scalable, allowing the assembly of much larger and ever more functional nanoprocessors.

"For the past 10 to 15 years, researchers working with nanowires, carbon nanotubes, and other nanostructures have struggled to build all but the most basic circuits, in large part due to variations in properties of individual nanostructures," says Lieber, the Mark Hyman Professor of Chemistry. "We have shown that this limitation can now be overcome and are excited about prospects of exploiting the bottom-up paradigm of biology in building future electronics."

An additional feature of the advance is that the circuits in the nanoprocessor operate using very little power, even allowing for their miniscule size, because their component nanowires contain transistor switches that are "nonvolatile."

This means that unlike transistors in conventional microcomputer circuits, once the nanowire transistors are programmed, they do not require any additional expenditure of electrical power for maintaining memory.

"Because of their very small size and very low power requirements, these new nanoprocessor circuits are building blocks that can control and enable an entirely new class of much smaller, lighter weight electronic sensors and consumer electronics," says co-author Shamik Das, the lead engineer in MITRE's Nanosystems Group.

"This new nanoprocessor represents a major milestone toward realizing the vision of a nanocomputer that was first articulated more than 50 years ago by physicist Richard Feynman," says James Ellenbogen, a chief scientist at MITRE.

Co-authors on the paper included four members of Lieber's lab at Harvard: Hao Yan (Ph.D. '10), SungWoo Nam (Ph.D. '10), Yongjie Hu (Ph.D. '10), and doctoral candidate Hwan Sung Choe, as well as collaborators at MITRE.

The research team at MITRE comprised Das, Ellenbogen, and nanotechnology laboratory director Jim Klemic. The MITRE Corporation is a not-for-profit company that provides systems engineering, research and development, and information technology support to the government. MITRE's principal locations are in Bedford, Mass., and McLean, Va.

The research was supported by a Department of Defense National Security Science and Engineering Faculty Fellowship, the National Nanotechnology Initiative, and the MITRE Innovation Program.


Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Harvard University, via EurekAlert!, a service of AAAS.

Journal Reference:

  1. Hao Yan, Hwan Sung Choe, SungWoo Nam, Yongjie Hu, Shamik Das, James F. Klemic, James C. Ellenbogen, Charles M. Lieber. Programmable nanowire circuits for nanoprocessors. Nature, 2011; 470 (7333): 240 DOI: 10.1038/nature09749
Source from: http://www.sciencedaily.com/releases/2011/02/110209131824.htm

Thursday, February 10, 2011

Police blame train crash on track workers - In Vietnam

Police blame train crash on track workers
Last updated: 2/8/2011 14:00
A taxi struck by the SE2 train in Dong Nai Province is moved from the accident scene on Sunday.

Police said on Tuesday that track workers were to blame for the train crash on Sunday night as they did not send signals to stop the approaching train, causing it to collide with six cars, killing two and injuring 24.

The accident happened when a northbound train crashed into six cars stuck on the Ghenh Bridge in the southern province of Dong Nai.

The narrow bridge, reportedly built more than 100 years ago, handles both car and train traffic.

Track workers in charge of the railway gate failed to stop cars from entering the bridge, leading to a serious traffic jam, police said.



They did not signal to stop the train from running into the cars either, they added.

Police said they are looking into pressing charges of irresponsibility in the accident.

Seven people have been detained so far, including the driver and the conductor of the train as well as the track workers.

The accident, a Lunar New Year tragedy, has raised concerns about similar accidents that could happen at junctions around the country where train paths run through roads used by cars and motorbikes.

Transportation officials said it has become necessary now to separate car and train traffic by building elevated train lines at such sites.

Reported by Tran Duy - From Thanhnien.com.vn

Learning English all the time

Nissan in New 600,000 Car Recall

Edited by Warren Johnson - Nguyen Nam Tran - Sunday, Nov 14, 2010

(Reuters) – Nissan Motor is recalling over 600,000 pickup trucks and cars because of concerns over their steering shafts. About 300,000 Nissan Frontier trucks like this 2001 model and over 280,000 X-terra sport utility vehicles are affected.

Around 85% of the recalled makes are in North America. Japan's number three automaker says it discovered that the lower steering column joint in these models can corrode and crack in extreme cases.

But Nissan adds there have been no accidents due to this problem. The automaker received three reports of the problem in Canada and six in Brazil. Nissan Motor is also recalling about 18,500 Sentra sedans due to a faulty battery connection. The carmaker says the fault could make starting the cars difficult, and cause stalling at low speeds.

In late October, Nissan recalled over 2 million cars, including its popular March subcompact. This brings the total number of vehicles recalled by Nissan in the past four weeks for over 2.6 million.

Nissan shares fell over 2% in Tokyo, outpacing broader weakness in the Japanese stock markets.


1. recall /rɪˈkɔːl/ (v) [transitive] recall something to ask for something to be returned, often because there is something wrong with it: thu hồi

  • to recall all the faulty cars: thu hồi toàn bộ xe bị lỗi
  • to recall cars with faulty brakes: thu hồi xe do lỗi ở hệ thống thắng

2. joint /dʒɔɪnt/ (n) a place where two or more parts of an object are joined together, especially to form a corner: khớp nối

3. corrode /kəˈroʊd/ (v) to destroy something slowly, especially by chemical action; to be destroyed in this way: ăn mòn

  • corroded parts of the engine: những chi tiết bị mòn trong động cơ

4. stall /stɔːl/ (v) [intransitive, transitive] (of a vehicle or an engine) to stop suddenly because of a lack of power or speed; to make a vehicle or engine do this: làm cho động cơ chết máy

  • The car stalled and refused to start again. Xe tắt máy và không khởi động lại được.
  • Learner drivers often stall their cars. Người học lái xe thường làm tắt máy xe.

Types of cars

  • pickup /ˈpɪkʌp/ a vehicle with low sides and no roof at the back used, for example, by farmers: xe tải nhỏ (mui trần) hay xe bán tải = pickup truck
  • SUV /ˌes juː ˈviː/ (sport-utility vehicles) is a vehicle that combines the load-hauling and passenger-carrying capacity of a large station wagon or minivan with features designed for off-road driving: xe thể thao đa dụng
  • sedan /sɪˈdæn/ a car with four doors and a boot/trunk (= space at the back for carrying things) which is separated from the part where the driver and passengers sit: xe hơi mui kín
  • subcompact / ˈsʌbkəmpækt/ a small car, smaller than a compact: xe ô tô nhỏ