China Science & Technology Forum

[JSCh]

FAST telescope is going to be the world largest single aperture radio telescope.
SKA telescope is going to be the world largest VLBI radio telescope. i.e. an array of radio telescopes combined as one.

Very-long-baseline interferometry - Wikipedia, the free encyclopedia

Very-long-baseline interferometry (VLBI) is a type of astronomical interferometry used in radio astronomy. In VLBI a signal from an astronomical radio source, such as a quasar, is collected at multiple radio telescopes on Earth. The distance between the radio telescopes is then calculated using the time difference between the arrivals of the radio signal at different telescopes. This allows observations of an object that are made simultaneously by many radio telescopes to be combined, emulating a telescope with a size equal to the maximum separation between the telescopes.​

Astronomical interferometer - Wikipedia, the free encyclopedia

An astronomical interferometer is an array of telescopes or mirror segments acting together to probe structures with higher resolution by means of interferometry. The benefit of the interferometer is that the angular resolution of the instrument is nearly that of a telescope with the same aperture as a single large instrument encompassing all of the individual photon-collecting sub-components. The main drawback is that it does not collect as many photons as a large instrument of that size. Thus it is mainly useful for fine resolution of the more luminous astronomical objects, such as close binary stars. Another drawback is that the maximum angular size of a detectable emission source is limited by the minimum gap between detectors in the array.[1]
​

FAST is more sensitive, SKA has better resolution.

 

[Martian2]

He's asking a very different question.

There is obviously FAST that is being built by China.

And there is the Square Kilometer Array being built by International Colloboration, both of which were listed as the largest telescopes. So which is true?

Also, Arecibo is a really old telescope.

You are confusing two different telescopes.

The Chinese FAST radio telescope is a large single telescope. It has incredible range. It should be able to see 2.67 times further than Arecibo. Objects that emit electromagnetic energy in the radio spectrum can be detected by the Chinese FAST that Arecibo cannot detect. Alternatively, China's FAST can see the same object with 2.7 times more clarity than Arecibo.

The Square Kilometer Array is an interferometer. It will have incredible resolution, because of the size of the virtual radio telescope dish via interferometry. However, it has a huge drawback. The range of the Square Kilometer Array is limited by the size of each small individual dish. The collective Square Kilometer Array interferometer cannot see any further than a single dish in its network. A single dish cannot gather data beyond its design sensitivity.

In conclusion, China's FAST is the world's largest telescope when you are discussing range. It can see deeper into space than any other radio telescope in the world. On the other hand, the Square Kilometer Array will have the world's highest resolution for any radio emitting object that is within the range of a single unit of the Square Kilometer Array.

 

[Keel]

Thanks guys for the explanations.
The radio telescope deals appear great for us that we can have access to the best of both worlds - one in depth the other in precision

 

[cirr]

Sorry guys，for readers well versed in Chinese only。

台风彩虹最新消息：我国首次用火箭探测台风内部 放多枚探空仪

发表时间：2015-10-07 09:22:21

关键字: 首次用火箭探测台风内部台风彩虹最新消息

台风彩虹最新消息：今年第22号台风“彩虹”日前过境广东、广西，造成较大灾害，与此同时，中国科研人员也发射火箭探测到“彩虹”的中心，探测其内部结构和强度，这是我国首次利用火箭探测台风的“内部世界”。

据人民网10月5日报道，2015年10月3日23时，伴随着一声轰隆的巨响，我国首枚台风探测火箭在海南万宁点火发射。

资料图：此前中国航天科工集团公司展示的近海台风探测火箭。

近海台风探测火箭发射瞬间。

仅仅6分钟后，探测火箭将多枚下投式探空仪成功送入远在数百公里之外的强台风“彩虹”云团中心区域并实时传送高质量观测数据。初步分析表明此次试验所获取的台风数据资料，精度高，质量好，同步性强，具有显著的科研业务应用潜在价值。此次试验完美解决了火箭发射、探空仪高空高速抛撒、远程数据获取等一系列技术障碍，获得圆满成功。

基于火箭平台下投式探空技术是由中国气象局上海台风研究所和中国航天科工集团，历时三年的共同设计研发的原创性创新台风探测手段，并最终在海南省气象局大力协助下展开首次试验。

这项探测试验技术主要用于探测海上台风的结构和强度，是一项军民融合，航天事业与国民经济生活特别是气象减灾应用结合的典范，也是一项多单位协同创新提高气象能力的探索性尝试。此次试验成功，标志着利用火箭平台的探测近海台风技术的重大突破，填补了我国海上台风结构和强度直接探测的空白。

发射总结

据参试专家介绍，试验的成功证明火箭探空台风技术对于分析研究近海台风的强度和内在结构特征有很强的参考价值和应用潜力，对于进一步提高台风路径和强度预报能力以及防台预警能力方面有着重大科学意义。此外，此次试验还得到了万宁市委、市政府以及万宁市气象局的大力支持。

发射过程示意图，火箭在空中多次变轨，投放多个探测器。

资料图：此前中国航天科工集团公司展示的近海台风探测火箭。

台风彩虹最新消息：我国首次用火箭探测台风内部 放多枚探空仪

 

[Bussard Ramjet]

Sorry guys，for readers well versed in Chinese only。

台风彩虹最新消息：我国首次用火箭探测台风内部 放多枚探空仪

发表时间：2015-10-07 09:22:21

关键字: 首次用火箭探测台风内部台风彩虹最新消息

台风彩虹最新消息：今年第22号台风“彩虹”日前过境广东、广西，造成较大灾害，与此同时，中国科研人员也发射火箭探测到“彩虹”的中心，探测其内部结构和强度，这是我国首次利用火箭探测台风的“内部世界”。

据人民网10月5日报道，2015年10月3日23时，伴随着一声轰隆的巨响，我国首枚台风探测火箭在海南万宁点火发射。

资料图：此前中国航天科工集团公司展示的近海台风探测火箭。

近海台风探测火箭发射瞬间。

仅仅6分钟后，探测火箭将多枚下投式探空仪成功送入远在数百公里之外的强台风“彩虹”云团中心区域并实时传送高质量观测数据。初步分析表明此次试验所获取的台风数据资料，精度高，质量好，同步性强，具有显著的科研业务应用潜在价值。此次试验完美解决了火箭发射、探空仪高空高速抛撒、远程数据获取等一系列技术障碍，获得圆满成功。

基于火箭平台下投式探空技术是由中国气象局上海台风研究所和中国航天科工集团，历时三年的共同设计研发的原创性创新台风探测手段，并最终在海南省气象局大力协助下展开首次试验。

这项探测试验技术主要用于探测海上台风的结构和强度，是一项军民融合，航天事业与国民经济生活特别是气象减灾应用结合的典范，也是一项多单位协同创新提高气象能力的探索性尝试。此次试验成功，标志着利用火箭平台的探测近海台风技术的重大突破，填补了我国海上台风结构和强度直接探测的空白。

发射总结

据参试专家介绍，试验的成功证明火箭探空台风技术对于分析研究近海台风的强度和内在结构特征有很强的参考价值和应用潜力，对于进一步提高台风路径和强度预报能力以及防台预警能力方面有着重大科学意义。此外，此次试验还得到了万宁市委、市政府以及万宁市气象局的大力支持。

发射过程示意图，火箭在空中多次变轨，投放多个探测器。

资料图：此前中国航天科工集团公司展示的近海台风探测火箭。

台风彩虹最新消息：我国首次用火箭探测台风内部 放多枚探空仪

At least give a broad summary.

 

[JSCh]

China launches cube satellites for civil aircraft tracking
Source:Xinhua Published: 2015-10-7 14:17:52


China has successfully launched three cube satellites (CubeSats), which are expected to help track civil aircraft and ships and avoid tragedies like missing flight MH370.

The three CubeSats in a mission coded STU-2 were launched on Sept. 25 and have entered their designed orbit, according to the mission's chief designer, Wu Shufan.

The three spacecraft are equipped with polar region observation cameras as well as automatic identification system (AIS) receivers for information from ships and automatic dependent surveillance-broadcast (ADS-B) receivers for messages sent from civil flights.

The ADS-B system was developed to be installed on civil aircraft and transmit readings of the flight's position, height, speed, direction and other information automatically every second to receivers on the ground or in the air. Currently more than 70 percent of aircraft have such systems installed.

As of the evening of Sept. 28, the STU-2 CubeSats had collected hundreds of thousands of ADS-B messages from more than 12,400 aircraft flying within receiving range.

The paths and traffic flow of civil flights within the satellites' monitoring area may be collected in real time.

"If there are enough satellites in orbit to cover a region wide enough, a specific flight could be tracked and that may help with spotting, search and rescue in cases like Malaysia Airlines flight MH370," Wu said.

CubeSats may also be used to provide information support for ship operations such as the Chinese icebreaker Xuelong (Snow Dragon) in polar regions.

Wu said the STU-2 mission, the first of its kind by China, is a step in the country's satellite network development for civil aircraft and ship monitoring.

He also called for more international cooperation to expand the network's reach.

Like a Rubik's cube, a CubeSat is a satellite composed of smaller cubic units. Depending on its different uses, a CubeSat may contain two, three or more such units.

Compared with other integral satellites, cube spacecraft are generally smaller, lighter and much more economical in development and production costs.

Wu said the three STU-2 CubeSats weigh only 6.8 kilograms in total.

 

[Martian2]

Look Out GoPro, Drone Giant DJI Is Getting Into The Handheld Camera Business | Fast Company | Business + Innovation

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Beautiful DJI Osmo video of Peru.

 

[JSCh]

Control the flow of light: Nature-inspired nanostructure created
Posted 4 days ago

The catenary is the curve that a free-hanging chain assumes under its own weight. It is a “true mathematical and mechanical form” in architecture described by Robert Hooke in the 1670s. The catenary could be found in many circumstances. For example, the silk on a spider’s web form multiple elastic catenaries. The catenaries are also widely used in architectures to construct bridges and arches.

Figure: An illustration of optical catenaries for the OAM generation. When a light beam incident on the catenary structures, orbital angular momenta are transferred from the structure to photons. This process is independent of the wavelength. Credit: SKLOTNM, Chinese Academy of Science​

In an article published in Science Advances, a journal established by the American Association for the Advancement of Science, Prof. Xiangang Luo from the Chinese Academy of Sciences and the co-workers have now demonstrated that ultrathin and lightweight optical devices could be constructed using nanostructures catenaries.

The researchers use optical catenary-shaped structures to convert circularly polarized light to helically-phased beam that carrying geometric linear phase profile. Similar to the “catenary of equal strength”, the phase gradient of the optical catenary is equal everywhere, which is a direct result of its special geometric shape. “The catenary structure could find applications in optics, architectures, and many other disciplines. This means that we could construct novel optical devices with strong similarity to the structures occurring in the natural world.” Prof. Luo explains.

Many previous methods used discrete nanostructures to generate space-variant phase distribution. The discrete structures lead to strong resonance, which makes the operating bandwidth of these samples limited. Prof. Luo’s group therefore uses the continuous catenary structures to obtain much broader bandwidth. They demonstrated that broadband orbital angular momentum (OAM) could be achieved by using the catenary array. The operating bandwidth of the devices could covers the entire electromagnetic spectrum ranging from microwave, terahertz, and infrared to the visible regime.

The catenaries could be used as a unique building block for optical metasurfaces, which are thought to be the key of the next-generation integrated optical systems. According to the metasurface-assisted law of reflection and refraction, many novel optical elements, such as flat lenses, axicons, and prisms, could be obtained with performance far beyond their traditional counterparts. Prof. Luo says, “The method of using catenary nanostructures to modulate phase works in many different cases. On the one hand, these nanostructures are natural candidates for the light manipulation on the nanoscale. On the other hand, when these structures are fabricated on flexible substrate, very lightweight and large-aperture lens could be realized. Such lenses make very large space telescopes become possible.”

Paper information: M. Pu, X. Li, X. Ma, Y. Wang, Z. Zhao, C. Wang, C. Hu, P. Gao, C. Huang, H. Ren, X. Li, F. Qin, J. Yang, M. Gu, M. Hong, X. Luo, Catenary optics for achromatic generation of perfect optical angular momentum. Sci. Adv. 1, e1500396 (2015). DOI: 10.1126/sciadv.1500396

Control the flow of light: Nature-inspired nanostructure created - Technology Org

 

[TaiShang]

Chinese scientists 3D-print building blocks of liver
October 9, 2015

A Chinese team has used a specialized 3D printer to produce tiny sections of the liver that could eventually be used a form a full artificial version of the organ, it announced on Friday.

The hepatic lobules, of which there are around a million in a human liver, were printed on the Regenovo 3D bio-print Work Station designed by the team at Hangzhou Electronic Science and Technology University.

This had a far more specific medical design than most 3D printers, which have industrial purposes, said team leader Xu Mingen.

 

[TaiShang]

Chinese Researchers Used 3D Printer for Liver

A Chinese team has used a specialized 3D printer to produce tiny sections of the liver that could eventually be used a form a full artificial version of the organ, it announced on Friday.

The hepatic lobules, of which there are around a million in a human liver, were printed on the Regenovo 3D bio-print Work Station designed by the team at Hangzhou Electronic Science and Technology University.

This had a far more specific medical design than most 3D printers, which have industrial purposes, said team leader Xu Mingen.

 

[AndrewJin]

Awesome

 

[cirr]

Chinese scientists 3D-print building blocks of liver
October 9, 2015

A Chinese team has used a specialized 3D printer to produce tiny sections of the liver that could eventually be used a form a full artificial version of the organ, it announced on Friday.

The hepatic lobules, of which there are around a million in a human liver, were printed on the Regenovo 3D bio-print Work Station designed by the team at Hangzhou Electronic Science and Technology University.

This had a far more specific medical design than most 3D printers, which have industrial purposes, said team leader Xu Mingen.

Hangzhou Electronic Science and Technology University.

Is this the same university that bio-printed kidneys last year？

China unveils the world’s largest 3-D printed structure

ALEXANDRA SARABIA

October 8, 2015 at 4:00 PM EDT | Updated: Oct 9, 2015 at 4:49 PM

Photo by Beijing Design Week.

VULCAN, the world’s largest 3-D printed architectural structure, was recently unveiled during Beijing Design Week 2015.

The pavilion, which is displayed in Beijing’s Parkview Green was constructed from 1,023 individually printed 3-D units and measures 26.5 feet in length and 9.5 feet in height, according to Inhabitat. Twenty large-scale 3-D printers were used to complete the units that assemble the pavilion, as described on the site Designboom. The white undulating lattice structure resembles a volcano, hence the name Vulcan, the Latin term for volcano. Silkworm cocoons inspired the architects behind the design, Yu Lei and Xu Feng of the Laboratory for Creative Design.

3-D printing creates three-dimensional objects from computer-generated designs. A design can be made using digital or animation modeling software like computer-aided design, which can then be sent to a 3-D printer, as explained in Mashable. Rubber and plastic can be used to make these designs.

Previously, only small-scale objects from industries ranging from fashion tomedicine could be 3-D-printed. There has been much discussion about how 3D printing could transform the architecture and construction industries.

VULCAN was just awarded the Guinness World Record for the world’s largest 3-D printed structure.

China unveils the world's largest 3-D printed structure

 

[cirr]

China successfully launches Pujiang-1 satellite featuring 3D printed parts into space

Sep 28, 2015 | By Alec

Over the past year or so, we’ve seen that the Chinese government is very enthusiastically adopting high quality 3D printing in a variety of its branches. In January, we saw how their warships are taking 3D printers out on missions to manufacture replacement parts and just a few weeks ago the army branch has started doing the same. However China is also ambitious in regards to aerospace, so it is hardly surprising that they have relied on the same high quality metal 3D printing principles during the development of a recent satellite. Called the Pujiang-1, it is the Chinese first satellite to feature 3D printed parts and has just been successfully launched.

The Pujiang-1 was one of four satellites that were carried into space on 25 September by the solid-fuel Long March-11 rocket. Lift-off took place at the Jiuquan Satellite Launch Center in Gansu (Northwestern China), at 9:41 AM (local time).

While NASA has also been experimenting with 3D printed satellite parts in recent years, the Pujiang-1 is a particularly interesting creation. Developed by the Shanghai Academy of Spaceflight Technology, its designers chose to reduce costs and manufacturing time by creating the satellite’s titanium antenna holder with 3D printing. These parts were completed over a period of three days, while they usually take up to four months to create. And despite this short production time, the performance of the parts are said to be completely similar to those of traditionally manufactured parts.

But aside from an excellent money-saving innovation, the Pujiang-1 is also part of Beijing’s ambitious ‘internet plus’ strategy. With an eye on the country’s economy, this plan aims to transform Chinese businesses by making high-speed internet widely available. Through Wi-Fi technology principles, the satellite is intended to conveniently collect and send data on things like the weather, traffic and population growth to the people – perfect data for supporting marketing strategies and even for resource surveys, emergency response and rescue, and much more.

The problem with those kinds of satellite programs in China is that they usually take exceptionally long to develop – establishing a dedicated program, creating and testing the models and prototypes quickly takes years. However, 3D printing technology is perfect for not only drastically reducing the costs involved, but also for greatly speeding up the program itself. If successful, the same principles will likely be applied to further satellite programs in China.

3ders.org - Singapore: Ultra Clean Asia Pacific opens largest 3D printing factory in Southeast Asia | 3D Printer News & 3D Printing News

 

[TaiShang]

While NASA has also been experimenting with 3D printed satellite parts in recent years, the Pujiang-1 is a particularly interesting creation. Developed by the Shanghai Academy of Spaceflight Technology, its designers chose to reduce costs and manufacturing time by creating the satellite’s titanium antenna holder with 3D printing.

3D printing put in multiple use, from medical care to space.

Good job!

 

[AndrewJin]

3D printing put in multiple use, from medical care to space.

Good job!

One aspect of the industrial revolution.