题干

如图所示为一种获得高能粒子的装置.环形区域内存在垂直纸面向外、大小可调节的匀强磁场.质量为m、电量为+q的粒子在环中做半径为R的圆周运动.A、B为两块中心开有小孔的极板,板间距为d.A、B板原来电势都为零,每当粒子飞经A板向B板运动时,A板电势升高为+U,B板电势仍保持为零,粒子在两板间电场中得到加速.每当粒子离开B板时,A板电势又降为零.粒子在电场一次次加速下动能不断增大,而绕行半径不变.粒子的重力忽略不计.

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    If you could be anybody in the world, who would it be? Your neighbour or a super star? A few people have experienced what it might be like to step into the skin of another person, thanks to an unusual virtual reality(虚拟现实)device. Rikke Wahl, an actress, model and artist, was one of the participants in a body swapping experiment at the Be Another lab, a project developed by a group of artists based in Barcelona. She swapped with her partner, an actor, using a machine called The Machine to Be Another and temporarily became a man. "As I looked down, I saw my whole body as a man, dressed in my partner's pants," she said. "That's the picture I remember best."

    The set-up is relatively simple. Both users wear a virtual reality headset with a camera on the top. The video from each camera is sent to the other person, so what you see is the exact view of your partner. If she moves her arm, you see it. If you move your arm, she sees it.

    To get used to seeing another person's body without actually having control of it, participants start by raising their arms and legs very slowly, so that the other can follow along. Eventually, this kind of slow synchronised(同步的)movement becomes comfortable, and participants really start to feel as though they are living in another person's body.

    Using such technology promises to alter people's behaviour afterwards-potentially for the better. Studies have shown that virtual reality can be effective in fighting racism-the bias(偏见)that humans have against those who don't look or sound like them. Researchers at the University of Barcelona gave people a questionnaire called the Implicit Association Test, which measures the strength of people's associations between, for instance, black people and adjectives such as good, bad, athletic or awkward. Then they asked them to control the body of a dark skinned digital character using virtual reality glasses, before taking the test again. This time, the participants' bias scores were lower. The idea is that once you've "put yourself in another's shoes" you're less likely to think ill of them, because your brain has internalised the feeling of being that person.

    The creators of The Machine to Be Another hope to achieve a similar result. "At the end of body swapping, people feel like holding each other in their arms," says Arthur Pointeau, a programmer with the project. "It's a really nice way to have this kind of experience. I would really, really recommend it to everyone."

同类题5

阅读《驿路梨花》选段,完成下列各题。

    我们正在劳动,突然梨树丛中闪出了一群哈尼小姑娘。走在前边的约莫十四五岁,红润的脸上有两道弯弯的修长的眉毛和一对晶莹的大眼睛。我想:“她一定是梨花。” 

    瑶族老人立即走到她们面前,深深弯下腰去,行了个大礼,吓得小姑娘们像小雀似的蹦开了,接着就哈哈大笑起来:“老爷爷,你给我们行这样大的礼,不怕折损我们吗?”

    老人严肃地说:“我感谢你们盖了这间小草房。”

    为头的那个小姑娘赶紧摇手:“不要谢我们!不要谢我们!房子是解放军叔叔盖的。”

    接着,小姑娘向我们讲述了房子的来历。十多年前,有一队解放军路过这里,在树林里过夜,半夜淋了大雨。他们想,这里要有一间给过路人避风雨的小屋就好了,第二天早上就砍树割草盖起了房子。她姐姐恰好过这边山上来抬菌子,好奇地问解放军叔叔:“你们要在这里长住?”解放军说:“不,我们是为了方便过路人。是雷锋同志教我们这样做的。”她姐姐很受感动。从那以后,常常趁砍柴、拾菌子、找草药的机会来照料这小茅屋。

原来她还不是梨花。我问:“梨花呢?”

     “前几年出嫁到山那边了。”

    不用说,姐姐出嫁后,是小姑娘接过任务,常来照管这小茅屋。

    我望着这群充满朝气的哈尼小姑娘和那洁白的梨花,不由得想起了一句诗:“驿路梨花处处开”。