A Chinese supercomputer has been ranked the world's second-fastest machine in a list issued by US and European researchers, highlighting China's ambition to become a global technology center.

The Nebulae system at the National Supercomputing Centre in Shenzhen, South China, came in behind the US Department of Energy's Jaguar in Oak Ridge, Tennessee, according to the list released on Monday.

Supercomputers are used for complex work such as modeling weather systems, simulating nuclear explosions and designing jetliners.

The biannual Top-500 list highlighted Beijing's efforts to join the United States, Europe and Japan in the global technology elite and its sharp increases in research spending, driven by booming economic growth.

It also reflected China's continued reliance on Western know-how: Nebulae was built by China's Dawning Information Industry Ltd, but uses processors from Intel and Nvidia, both American companies.

The Nebulae is capable of sustained computing of 1.271 petaflops - or 1,271 trillion calculations - per second, according to the Top 500. It said the Jaguar was capable of sustained computing of 1.75 petaflops.

The Chinese computer ranked first in theoretical computing speed at 2.98 petaflops, the group said.

The list was compiled by Hans Meuer of the University of Mannheim, Germany, Erich Strohmaier and Horst Simon of the NERSC/Lawrence Berkeley National Laboratory and Jack Dongarra of the University of Tennessee, Knoxville.

Beijing wants China to evolve from a low-cost factory into an prosperous "innovation society". A 15-year government plan issued in 2006 promises support for areas ranging from computers to lasers and genetics.

Boosted by Nebulae's performance, China rose to No 2 overall on the Top 500 list, with 24 of the 500 systems on the list and 9.2 percent of global supercomputing capacity, up from 21 systems six months ago.

The US held on to its overall lead with 282 of the 500 systems and 55.4 percent of installed performance.

Europe had 144 systems on the list, including 38 in Britain, 29 in France and 24 in Germany.

Elsewhere in Asia, Japan had 18 supercomputers on the list, up from 16 six months ago, and India had five.

A second Chinese computer also made the Top 10. The Tianhe-1 at the National Super Computer Center in the eastern city of Tianjin, which was ranked No 7, uses processors made by Intel and Advanced Micro Devices Inc, another US company.

The list also reflected breakneck advances in supercomputing speeds.

No 1 on the June 2008 list was the Roadrunner system at the Los Alamos National Laboratory in New Mexico, capable of 1.04 petaflops, or about two-thirds of Jaguar's speed. In the latest list, the Roadrunner dropped to No 3.