Less Is More
It sounds all wrongdrilling holes in a piece of wood to make it more resistant to knocks. But it works because the energy from the blow gets distributed throughout the wood rather than focusing on one weak spot. The discovery should lead to more effective and ligher packaging materials.
Carpenters have known _____1_____ centuries that some woods are tougher than others. Hickory, for example, was turned into axe handles and cartwheel spokes because it can absorb shocks without breaking. White oak, for example, is much more easily damaged, ____2____ it is almost as dense.1 Julian Vincent at Bathe University and his team were convinced the woods internal structure could explain the differences.
Many trees have tubular vessels that run _____3____ the trunk and carry water to the leaves. In oak they are large, and arranged in narrow bands, but in hickory they are smaller, and more evenly distributed. The researchers ____4____ this layout might distribute a blows energy throughout the wood, soaking up a bigger hit. To test the idea, they drilled holes 0.65 millimetres across into a block of spruce, a wood with ____5____vessels, and found that____6___ withstood a harder knock. ___7___ when there more than about 30 holes per square centimeter did the woods performance drop off.
A uniform substance doesnt cope well with knocks because only a small proportion of the material is actually _____8____. All the energy from the blow goes towards breaking the material in one or two places, but often the pieces left ____9___ are pristine.
But instead of the energy being concentrated in one place, the holes provide many weak spots that all absorb energy as they break, says Vincent. You are controlling the places _____10____ the wood breaks, and it can then absorb more ____11____, more safely.
The researchers believe the principle could be applied to any material____12____ example, to manufacture lighter and more protective packaging. It could ____13____ be used in car bumpers, crash barriers and armour for military vehicles, says Ulrike Wegst, ____14_____ the Max Plank Institute for Mental Research in Stuttgart. But she emphasizes that youd _____15_____ to to design the substance with the direction of force in mind. The direction of loading is crucial, she says.
1. A) for B) since C) in D) at
2. A) but B) although C) and D) despite
3. A) down B) over C) up D) into
4. A) discovered B) concluded C) found D) thought
5. A) no B) per C) each D) every
6. A) the idea B) it C) they D) the spruce
7. A) If B) Just C) Only D) Rarely
8. A) effected B) beaten C) slapped D) affected
9. A) behind B) beyond C) for D) intact
10. A) which B) where C) that D) there
11. A) water B) air C) energy D) safety
12. A) among B) in C) as D) for
13. A) also B) besides C) else D) yet
14. A) over B) at C) around D) on
15. A) necessity B) must C) need D) had
体坛英语资讯:IOC Evaluation Commission arrives in Paris for a three-day inspection
国际英语资讯:Spotlight: Trump, Erdogan vow to repair U.S.-Turkish relationship amid existing differences
体坛英语资讯:Swedish player Rebecca Peterson wins WTA Tianjin Open
印度首都德里雾霾爆表,空气污染指数达到999
听流行音乐为什么让人愉悦?科学家找到原因了
荷兰决定将车辆限速降到欧洲最低
体坛英语资讯:IOC Evaluation Commission kicks off three-day inspection in Paris for Olympics bid
美文欣赏:善良,从来都不是白费的
新发现:你掌握的语言会改变你对时间的感知
国际英语资讯:Merkel, Macron agree to strengthen eurozone after first meeting
国内英语资讯:China eyes closer ties with UN to advance global agenda
国际英语资讯:S.Korea, U.S. to hold talks for upkeep cost-sharing for USFK
国内英语资讯:China, Britain vow closer cooperation, communication
国内英语资讯:Chinas vice president meets with ICRC, IFRC leaders
小米推出自己的Apple Watch,据说和苹果差不多
体坛英语资讯:Vasco youth players injured in bus crash
人造肉风潮持续大热,Beyond Meat赚翻了
国内英语资讯:Direct flights link China with 43 Belt and Road countries
国际英语资讯:Iran woos foreign firms to develop railway projects
国际英语资讯:Two giant pandas in Dutch zoo to meet public on May 30
国内英语资讯:Xi elaborates on inspiration behind Belt and Road Initiative
体坛英语资讯:Nadal beats Djokovic to reach 8th Madrid final
白宫否认川普向俄官员泄露高度机密情报
国内英语资讯:China Focus: Riding on fruitful forum, confident Xi takes Belt & Road to next level
川普即将会晤埃尔多安
时尚界核弹:德国公司推出可更换鞋跟的女鞋
体坛英语资讯:Bayern overpower Leipzig, Hoffenheim crush Bremen in German Bundesliga
哈利波特前传手稿被盗,罗琳呼吁大家不要买
H&M总裁担心环保思潮会影响整体经济
国际英语资讯:Frances new PM Philippe takes office
不限 |
英语教案 |
英语课件 |
英语试题 |
不限 |
不限 |
上册 |
下册 |
不限 |