News on China's scientific and technological development.

siegecrossbow

General
Staff member
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A group of scientists from China may have created a stealth material that could make future fighter jets very difficult to detect by some of today’s most cutting-edge anti-stealth radar.

The researchers developed a new material they say can defeat microwave radar at ultrahigh frequencies, or UHF. Such material is usually too thick to be applied to aircraft like fighter jets, but this new material is thin enough for military aircraft, ships, and other equipment.

Today’s synthetic aperture radar use arrays of antennas directing microwave energy to essentially see through clouds and fog and provide an approximate sense of the object’s size, the so-called radar cross section. With radar absorbent material not all of the signal bounces back to the receiver. A plane can look like a bird.

“Our proposed absorber is almost ten times thinner than conventional ones,” said Wenhua Xu, one of the team members from China’s Huazhong University of Science and Technology, in a statement.

In their paper, published today in the
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, the team describes a material composed of semi-conducting diodes (varactors) and capacitors that have been soldered onto a printed circuit board. That layer is sitting under a layer of copper resistors and capacitors just .04 mm thick, which they called an “active frequency selective surface material” orAFSS. The AFSS layer can effectively be stretched to provide a lot of absorption but is thin enough to go onto an aircraft. The next layer is a thin metal honeycomb and final is a metal slab.

The good news: the material isn’t locked away in a lab but published openly, so it’s not going to surprise anyone.

Stealth is considered by many to be one of the key technologies that enabled U.S. military dominance throughout the last century, effectively neutralizing, or offsetting, technological gains made by rival nations and the Soviet empire.

“In the 1970s, Secretary of Defense Harold Brown, working closely with Undersecretary – and future Defense Secretary – Bill Perry, shepherded their own offset strategy, establishing the Long-Range Research and Development Planning Program that helped develop and field revolutionary new systems, such as extended-range precision-guided munitions, stealth aircraft, and new intelligence, surveillance, and reconnaissance platforms,” former Defense Secretary Chuck Hagel
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at a November 2014 event outlining the Pentagon’s newest technological push.

The F-35’s stealth capabilities are often touted as the jet’s most valuable feature. But in 2009, China was
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able to steal design and electronics data related to the program. China’s J-31 fighter resembles the F-35 to
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, leaving many to wonder if the electronics on the inside are a match as well.

The publication today won’t answer that question but does speak to a growing Chinese capability in stealth technology, an area where the United States once had clear dominance.
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siegecrossbow

General
Staff member
Super Moderator
I found this originally from another article which taunted that how this discovery served the Chinese no more since they gave it away by publishing the paper. Now everyone knows how to do it according to them. A lot of this is happening lately since there's steadily increasing number of Chinese advancements where they have to knock it some way to comfort their insecurity.

They don't think that China has better stuff under wraps? :p
 

broadsword

Brigadier
I won't say much more except that when the American military labs and silicon valley are disproportionately staffed by Chinese scientists, they ought to rethink the western trope of "uncreative Asians".

I am sure everyone here is aware of the contribution of Chinese scientists in American labs, especially in the area of batteries and materials. Li may be the scientific name for lithium, but is also often the eponymous name of the inventor within the context.
 

Equation

Lieutenant General
Here's another article about China's latest development of stealth material.

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Researchers from China have reportedly turned out a
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that is far more advanced than anything out there today. Published in the Journal of Applied Physics, the technology behind it is called “active frequency selecting surface” (AFSS), and it is described as an ultra-thin multi-layered material that is only 7.8mm thick. The technical details of this material are impressive.

The first 7mm of the composite is a honeycomb substrate that supports the outer layers and separates them from the metal outer surface of the craft to which it is applied. Next comes a copper-and-semiconductor AFSS layer that runs 0.04mm thick, and this leads to an outer layer called FR4. FR4 is a material used in printed circuit boards which is able to variably tune itself to absorb a wide band of radio frequencies.

Due to its utility and physical properties, it is possible to use the material on many different types of craft, including drones, fighter jets, satellites, and more. It appears that this technology will make its way over to Chinese jets and ships, making them harder to detect.

This new material is designed to defeat microwave radar at the UHF band level. With its thin profile, this type of material is applicable to fighter jets, defeating a practical limitation found in previous materials.

Stealth technology, and radar evasion in aircraft technology, have been part of a longstanding cat-and-mouse game between the major military powers extending over many years. From the earliest days of high altitude craft, to the ultra-sophisticated materials that are placed on craft today, the goal is to be invisible to the tools of detection. Stealth aircraft materials are designed to break up and change the normal way in which radar waves bounce of a craft’s surfaces. In time, radar detection equipment has become increasingly fine-tuned in order to counteract these stealth techniques. Today, detection technology uses ultra-high frequencies (UHF), which have enabled higher resolution than ever before.
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Still on top for sixth year in a row

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Tuesday, November 17, 2015, 09:50
Tianhe-2 remains world's best supercomputer
WASHINGTON - China's Tianhe-2 supercomputer has retained its position as the world's most powerful system for the sixth year in a row, according to a biannual Top500 list of supercomputers released Monday.

Tianhe-2, or Milky Way2, with a performance of 33.86 petaflops per second (Pflop/s), was developed by China's National University of Defense Technology and deployed at the National Supercomputer Center in Guangzhou. It has held the title since June 2013.

The Chinese system is almost twice as fast as the next on the list, Titan of the US Department of Energy, which has a performance of 17.59 Pflop/s.

In fact, there has been no change among the ranking of the world's top5 supercomputers since June 2013 in the latest edition of the closely watched list.

"The top five computers are very powerful and expensive," Jack Dongarra, professor of the University of Tennessee and editor of the report, said in an email. "It will take perhaps another year before a new system enters the top five."

Among the significant changes to this list from July 2015's list is the sharp decline in the number of systems in the United States, now at 201.

"This is down from 231 in July and is the lowest number of systems installed in the US since the list was started in 1993," the statement said.

In contrast, China made "a great leap" to 109 systems.

"China received a big boost from Sugon, Lenovo and Inspur," said Dongarra. "The large number of submissions came from Sugon."

According to the Top500 statement, Sugon has overtaken IBM in the system category with 49 systems, while Lenovo, which acquired IBM's x86 server business last year, has 25 systems in the list, up from just three systems on the July 2015 list.

In addition, some systems that were previously listed as IBM are now labeled as both IBM/Lenovo and Lenovo/IBM.

Inspur, the third vendor from China, now has 15 systems on the list.

"China is ... carving out a bigger share as a manufacturer of high performance computers with multiple Chinese manufacturers becoming more active in this field," the statement concluded.

Overall, HP leads the list with 156 systems followed by Cray with 69 systems and China's Sugon with 49 systems. IBM ranks fourth with 45 systems. Lenovo ranked sixth while Inspur ranked eighth on the list.

The Top500 list is considered one of the most authoritative rankings of the world's supercomputers. It is compiled on the basis of the machines' performance on the Linpack benchmark by experts from the United States and Germany.
 

Equation

Lieutenant General
Overall, HP leads the list with 156 systems followed by Cray with 69 systems and China's Sugon with 49 systems. IBM ranks fourth with 45 systems. Lenovo ranked sixth while Inspur ranked eighth on the list.

HP is better than IBM in that ranking? Sorry I'm not a big fan of HP computers, but I do like their printers and plotters for large paper size prints.
 

vesicles

Colonel
I think computer stuff is only a minor part of HP's operations. Printers would be another one. What most people don't know is that HP is a major player in the scientific instruments field. Majority of the most advanced gas chromatography (GC) and high pressure liquid chromatography (HPLC) equipment come from HP.
 
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