News on China's scientific and technological development.

M

mzyw

Junior Member
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China's fourth scientific research station on Antarctica will be set up during an expedition to the southern continent by the Chinese icebreaker Xuelong that will begin on Nov 7.
"Taishan Station, named after Taishan Mountain in Shandong province, will be located at Princess Elisabeth Base ... and will be an important connection between Zhongshan Station, which was built in 1989, and the south pole," said Liu Shunlin, chief scientist at the Polar Research Institute of China and leader of this year's expedition.
Xuelong will sail for an estimated 58,000 km over 155 days, carrying a 280-member expedition team.
It will be the first time that Chinese scientists have sailed around Antarctica.
China will build another station on Antarctica in the next three years to carry out more scientific research, especially on climate change and environmental change.
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AssassinsMace

AssassinsMace

Lieutenant General
I would guess you can learn something from how light refracts in water. It isn't about how it only works in water. If it's useless for a sub, it pretty much useless for nearly everything else because visual contact isn't going to be the first contact.
 
N

no_name

Colonel
Strictly speaking light does not refract under water but through the air-water boundary, or at medium discontinuities.

Of course water density will vary with depth/temperature, and that's what will need to be taken into account when operating sonars. But given how fast light attenuates under water refraction from those sort of effects probably can be ignored.

I would guess it is not water in that cube but another transparent liquid.
 
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broadsword

broadsword

Brigadier
China invents low-cost welding robot

English.news.cn 2013-11-05

HEFEI, Nov. 5 (Xinhua) -- Chinese scientists announced on Tuesday that they had invented a low-cost welding robot, which can help improve welding efficiency for small factories.

The Hefei Institute of Physical Science under the Chinese Academy of Sciences took six months to develop the robot, which costs a quarter of existing models in the world.

It is expected to weld metal structural parts and works for non-standard welding projects, said Dr. Li Tao, director of the project.

According to Li, the robot adopts Selective Compliance Assembly Robot Arm (SCARA) technology, which allows it to move more easily, respond more quickly and improve the accuracy of positioning. It is also designed to remember working paths and repeat the same operation automatically.


An explanation on SCARA

In general, traditional SCARA’s are 4-axis robot arms, i.e., they can move to any X-Y-Z coordinate within their work envelope. There is a fourth axis of motion which is the wrist rotate (Theta-Z). The ‘X’, ‘Y’ and the ‘Theta-Z’ movements are obtained with three parallel-axis rotary joints. The vertical motion is usually an independent linear axis at the wrist or in the base.

By virtue of the SCARA’s parallel-axis joint layout, the arm is slightly compliant in the X-Y direction but rigid in the ‘Z’ direction, hence the term: Selective Compliant. This is advantageous for many types of assembly operations, e.g., inserting a round pin in a round hole without binding.

The second attribute of the SCARA is the jointed two-link arm layout similar to our human arms, hence the often-used term, Articulated. This feature allows the arm to extend into confined areas and then retract or “fold up” out of the way. This is advantageous for transferring parts from one cell to another or for loading/ unloading process stations that are enclosed.

SCARA’s are generally faster and cleaner than comparable Cartesian systems. Their single pedestal mount requires a small footprint and provides an easy, unhindered form of mounting. On the other hand, SCARA's can be more expensive than comparable Cartesian systems and the controlling software requires inverse kinematics for linear interpolated moves. This software typically comes with the SCARA though and is usually transparent to the end-user.
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P

Preux

Junior Member
antiterror13 said:
welll ......, you are comparing apple with orange

you are comparing demonstration (prototype?) cultivation in China vs national average in the US

unfortunately, it doesn't work that way :eek:

Agriculture productivity in the US is far higher than in China
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Depends on what metric you use. On a per-farmer basis the US IS far more productive, on a per unit area, China is more productive by a large margin, I don't have any solid figures on capital input per unit yield but I suspect it'll tell its own story. Then too you need to consider the specific sector - purely as an example, Chinese grain production is hugely more productive than the US in terms of per unit area yield, while I strongly suspect certain cash crops or livestock industry would see the US with a commanding lead, etc and so on.
 
B

B.I.B.

Captain
PanAsian said:
I wonder how much of the stopping power is due to the glass and how much is due to the rest of the phone. I think it has gorilla glass or whatever the latest tough glass is for smartphones.
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There is also the possibility the phone had nothing to do with the mans good fortune in not being injured or killed.

The thief could have used a low velocity .22 handgun. With such a gun you could fire several bullets into the person at close range with such a weapon and provided the bullet did not hit any vital organ, there's a excellent chance he would survive.
 
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