题型:阅读理解 题类:常考题 难易度:普通
广东省珠海市2018-2019学年高二上学期英语期末考试试卷
Dutch officials toasted on Tuesday the opening of what is being called the world's first 3D-printed concrete bridge, which is meant to be used by cyclists. There was applause as officials wearing hard hats and workmen's jackets rode over the bridge on their bikes at the opening ceremony in the southeastern town of Gemert.
“The bridge is not very big, but it was rolled out by a printer which makes it unique,” Theo Salet, from the Eindhoven University of Technology, told Dutch broadcaster NOS. Work on printing the bridge, which has some 800 layers, took about three months after starting in June and it is made of pre-stressed concrete, according to the university. “One of the advantages of printing a bridge is that much less concrete is needed than in the conventional technique in which a mould (泥浆) is filled,” it said on its website, adding “a printer deposits the concrete only where it is needed.”
The eight-metre (26-foot) bridge crosses a water-filled channel to connect two roads, and it was tested for safety to bear loads of up to two metric tons in cooperation with the BAM Infra Construction company. Although designed for bikes, it could take up to 40 trucks, the designers said “We are looking to the future,” said the head of BAM, Marinus Schimmel. “3D printing meant fewer rare resources were needed and there was significantly less waste,” he added.
The Netherlands is among countries, with the United States and China, taking a lead in the cutting-edge technology of 3D printing, using computers and robotics to construct objects and structures from scratch without using much traditional manpower. Last year a Dutch architect unveiled (提示) a unique 3D printer with which he hopes to construct an “endless loop” building. And a Dutch start-up called MX3D has begun printing a stainless-steel bridge, of which a third is already completed. The aim is to finish printing by March and lay the bridge over an Amsterdam canal in the future.
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This leaflet gives you the prices for Royal Mails UK and International services and Parcelforce Worldwide UK services — whether your item is to the UK or abroad, urgent or you simply want a standard service. To obey national and international regulations governing the carriage of mail, and ensure that mail in transport does not present a danger to the general public, we restrict or ban certain items from our network.
Letters |
Length Limit (cm) |
Width Limit (cm) |
Thickness Limit (cm) |
Weight Limit(g) |
Price(£/100g) |
Standard |
24 |
16.5 |
0.5 |
100 |
1.8 |
Large |
35.3 |
25 |
2.5 |
750 |
2.3 |
Parcels |
Length Limit (cm) |
Width Limit (cm) |
Depth Limit (cm) |
Weight Limit (kg) |
Price(£/kg) |
Small |
45 |
35 |
8 |
2 |
4.3 |
35 |
25 |
16 |
2 |
||
Medium |
61 |
46 |
46 |
20 |
6.8 |
Large |
150 |
300 |
60 |
30 |
9.0 |
Only available on Parcelforce Worldwide services. |
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