Red lanterns are hung high.

Text/Zhang Ran Xiao Yue

During the celebration of the 60th anniversary of the founding of New China, 60 high-tech red lanterns were raised on both sides of Tiananmen Square, which could resist the gale of category 4, shining under the starry sky.

The production of the red palace lantern in the celebration square was undertaken by 508, the Fifth Academy of China Aerospace Science and Technology Corporation. Different from traditional lanterns, the red palace lantern developed by 508 looks like a lantern, but it is actually a "big balloon" filled with helium. Under the condition that there are no appendages in the square space, these lanterns that don't need to be hung are balanced by the angle of the rope, and finally hang stably in the air.

The lantern is a double-layer structure, and the inner layer is an airbag filled with about 60 cubic meters of helium. The airbag is made of flexible textile material, which is similar to the parachute recovered by spacecraft in design principle, manufacturing technology and testing method.

Because hydrogen and helium are relatively light gases, and hydrogen is flammable and explosive, although the cost is low, so the celebration finally chose helium.

In the National Day celebration, the lanterns on both sides of Tiananmen Square should be prominent and solemn. In order to achieve this effect, 508 Institute required lanterns not to move in the air from the beginning of production. The staff used the "five-point tying method", that is, one end of the rope was connected to the lantern and the other end was connected to the ground ballast. The four ropes on the side are diagonal, and the rope in the middle is vertical.

The drawstring used to fix palace lanterns is made of special textiles, which is generally used as the rope for umbrella belts and parachutes. Its single strength is greater than 1 ton, cutting resistance and heat resistance, and light weight. The pull ropes for fixing the lanterns at five points are all (a) _ _ _ _ _ _ _ _, with a compressive load of 200 kg.

When releasing, put the vertical rope (B) in the middle of the lantern on the special tool and lift it by hand. All the other cables were stretched straight, and finally the red lantern floated quietly. The release of the whole site was assisted by 508 staff and more than 200 armed police. It takes about 1 hour for each lantern to inflate and lift off.

(Selected from Jinghua Times, September 20, 2009, with changes)

1. Why do you put quotation marks on the "hang" in the title?

_____________________________

2. What's so special about these 60 lanterns rising in Tiananmen Square?

_____________________________

Answer: Analysis:

1. Because there is no attachment in the square space, these lanterns don't need to be hung, but rely on the angle of the rope to achieve balance, and finally they are stably suspended in the air.

2.① Stable, resistant to level 4 wind; ② It is actually a "big balloon" filled with helium; ③ Balance is achieved by the angle of the rope. ...